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Identity / Music
We're All Right? Phil Harvey Spector, "Sign of the Times", and the Horror of Pop
by Mockingbird on Jul 6, 2017 • 1:50 pm 5 Comments
The following was written by our friend, Rachel Gaffin. A version of this article was originally published in The Ruckus last September.
The year my brother Richard discovered rock and roll, his Christmas gifts shared a common theme: one uncle bought him a giant red Visual Dictionary of Rock and Roll; another bought him a set of AC/DC boxers. At the time a wide-eyed ten-year-old, I watched my brother the way he watched videos of Hendrix wailing out "The Star-Spangled Banner" in '69: with reverence and a burning desire to imitate. Since the boxers weren't exactly accessible, I turned instead to the dictionary, seeking a chance to learn what Richard loved. The book read like a guide to the constellations; each star named occupied his or her proper place in the firmament of rock music.
On the back of the book, in glossy white type, read a quote from U2's frontman and music theorist, Bono: "Pop music tells you everything is OK. Rock music tells you everything is not OK, but you can change it." Bono's words were an exclamation point at the end of the book's thesis, that rock and roll was objectively the smartest, most human genre out there. Ten-year-old me swallowed the dictionary like gospel truth.
I hadn't thought of Bono's words or the dictionary for years when, a few days ago, upon the realization that the only food I had in my pantry was a box of pasta and a butternut squash, I drove to the grocery store, pop radio puttering in the background. As I daydreamed of Trader Joes' dark chocolate peanut butter cups, Twenty One Pilots' song "Heathens" came on, calling me to attention. I'd heard the song before, but I hadn't noticed its lyrics: "You're loving on the psychopath sitting next to you/You're loving on the murderer sitting next to you/You'll think, how'd I get here sitting next to you?" Far from claiming that everything is OK, Tyler Joseph, the duo's lead singer, doesn't even offer a chance for things to change. Instead, "Heathens," which spent eighteen consecutive weeks in the top ten of the Billboard Hot 100, peaking at number two, declares the not-OK-ness of things as fact.
If what audiences of pop music want, as Bono's words imply, is an invitation to escape into a better, brighter, bubblegum-pink reality, how did a song called "Heathens" make it to the top of the charts at all? Certainly, the song's position on the soundtrack for last summer's box office record-breaker, Suicide Squad, did not hurt the duo in breaking a few records themselves. In September 2016, Tyler Joseph and Josh Dun joined Elvis and the Beatles in the rare pantheon of artists who have had two songs at the same time in the Billboard's Top Five. But "Heathens"' success has more to it than blockbuster affiliation.
We love "Heathens" for the same reason we love Stephen King's The Shining and Netflix's wunderkind, Stranger Things: because there is nothing more thrilling than the skin-crawling realization that a monster may be lurking close at hand, "sitting next to you." Even more thrilling, more compelling, is what Twenty One Pilots invites their audience to consider when they sing, "it looks like you might be one of us." The thrill of it all, the horror that the song asks us to face, is the monster inside.
One has to look no further than the godfather of pop music production for "Heathens" to ring true. Philip Harvey Spector, born in the Bronx in 1939 to a first-generation immigrant Jewish family, innovated record production with his self-styled "Wagnerian" approach, leading to his invention of the "Wall of Sound". Instead of relying on a standard four- or five-piece band to carry the weight of his songs, Spector layered guitar over guitar, drum over drum, to create a rich sonic experience that melded the variegated instrumentation into one grandiose sonic explosion. If the bricks of his Wall were standard rock instruments stacked on top of each other, his mortar of choice were the orchestral instruments he employed, the woodwinds and the brass.
Starting in the late 50s, Spector's operatic approach swept the pop world. With "To Know Him is to Love Him," his band The Teddy Bears claimed the seventh-ever number one hit on the Billboard Hot 100, in December of '58. Girl groups became his specialty; under his direction, acts like The Crystals and The Ronettes enjoyed great success, with singles like "And Then He Kissed Me" and "Baby, I Love You," respectively. Spector's list of collaborators — Ike & Tina Turner, Leonard Cohen, Eric Clapton, the Rolling Stones, even the Beatles — reads like a mini Hall of Fame. His influence is still palpable; as recently as 2004, 46 years after his first hit single, Rolling Stone placed Spector on their list of the "Greatest Artists of All Time," and in 2008, the Washington Times named him the second greatest record producer of all time. Amy Winehouse was often known to sample "To Know Him is to Love Him," and countless bands, pop and otherwise, produced today are much indebted to Spector's pioneering soundscape style — MS MR, The Japanese House, even Bon Iver, to name a few.
Yet, in the midst of all his creative fervor, despite (or perhaps because of) his wild success, a monster lurked inside of Spector. On February 3, 2003, Lana Clarkson, an actress and model, was found dead in Spector's mansion, shot in the mouth, her teeth scattered across the floor. In 2009, after two years of legal proceedings, Spector was sentenced to 19 years to life in prison, and is currently 12 years away from eligibility for parole, his name now followed by one more definition: murderer.
In retrospect, the monster in Spector didn't appear entirely out of nowhere; like any horror story, there were clues all along, lurking. Multiple rumors purport Spector's propensity for pulling guns on people, specifically the artists he worked with in the 70s and 80s. Again, the list reads like a Hall of Fame: John Lennon, Leonard Cohen, Debbie Harry (of Blondie), The Ramones, and his wife at the time, Ronnie Spector. Though some of these instances are in dispute — Marky Ramone claims that all Spector did was carry the gun with him into recording sessions — Spector by all accounts lived close to the edge of destruction for years before he took Clarkson's life, and with it, his own. And yet Spector's story still takes us aback, still thrills us — how can someone so creative, so innovative, be capable of such destruction?
Pop music today has embraced the thin line that Spector, one of its first pioneers, tread for so long, the line between creation and destruction. Check the Billboard Hot 100 for evidence: this past fall, Mike Posner's lonely "I Took a Pill in Ibiza", The Weeknd's addiction anthem "Prisoner" (a collaboration with the queen of self-destruction, Lana Del Rey), and another Suicide Squad track, "Sucker for Pain," by Lil Wayne, et al., stood with "Heathens" in proclaiming that everything's not just OK. Today, Harry Styles' vaguely apocalyptic "Sign of the Times" paints a hazy picture of the end of civilization; meanwhile, Ed Sheeran's otherwise soaring "Castle on the Hill" confronts the ugly realities of divorce and overdose. Even the Chainsmokers' resilient hit, "Closer," where Halsey literally sings that she's "okay," colors her claim with a drinking problem. And the charts aren't the only place to witness pop music's embrace of humanity's dark side; tabloids and Twitter feuds reveal as much about the celebrities they feature as they do about their audiences' desire to eat it all up.
Perhaps at the time that Bono claimed pop music's basic thesis is the OK-ness of everything, he was right. The music Spector himself produced often portrayed the world as sun-dappled and rarefied. But pop music today refuses to be so simple, so easy. Chalk it up to post-modern angst or a culture long-jaded to the psychedelic optimism of the sixties, but pop no longer shies away from the darkness inside. Instead, pop has embraced the uniquely human, age-old tension between light and dark, our hope for good and the horror of what we might do if we, like Spector, snap.
Tags: Bono, Harry Styles, Heathens, Lana del Rey, Low Anthropology, Mike Posner, Phil Spector, pop music, Rachel Gaffin, Suicide Squad, twenty one pilots
Read more on and from Mockingbird.
CJ Green says:
This is fascinating, Rachel! My wife & I did an experiment after reading this—listened to pop radio for a 20-minute drive & we got back to back sad songs: "Pill in Ibiza," "I don't wanna live forever," B.O.B.'s "Airplanes" & "Let it go" by James Bay. All great songs — but so, so sad…
I don't think it hurts the overall argument, but to try and save you some grief, the lyrics actual say, "You'll never know the …" and not, "You're loving on the…"
In "Not Today" by Twenty One Pilots, he overtly says:
Listen, I know this one's a contradiction because of how happy it sounds,
But the lyrics are so down,
It's OK though, because it represents, wait better yet, it is,
Who I feel I am right now
David Zahl says:
As a Spector obsessive, I loved this post more than I say. Thank you Rachel. Proud we got to host/publish it.
Can't not mention this:
https://mbird.com/2010/08/weds-morning-rock-n-roll-dion-and-phil/
Alone Together In Our Third Places | Mockingbird says:
[…] The following was written by Rachel Gaffin. […]


On 4 April 2019, the RMCD announced that the new module for application of exemption items C3 and C4 have been 'live' on MySST system on 1 January 2019. Hence, the certificates generated prior to this date can no longer be used after 1 June 2019.
The Taxation Practice Committee of the Institute will review the comments or feedback for submission to the RMCD. Kindly provide your comments or feedback (if any) on or before 17 April 2019.
29 Mar 2019 Customs (Anti-Dumping Duties) (Extension) Order 2019 P.U.(A) 95/2019 comes into operation on 30/03/2019 The effective period of P.U.(A) 81/2014 and P.U.(A) 239/2016 is extended and shall remain in force from 30.03.2019 to 26.09.2019.


Last week I had the opportunity to float the Boise River with two dear friends – Cathy Kearns of Reiki Renewal and Pip Oxlade of Lady of the Rainbow Heart visiting from New Zealand – and my daughter. We are healers: all four of us being Reiki practitioners and three of us also being certified ThetaHealing® Meditation Technique Practitioners. If you haven't heard of ThetaHealing® you might be curious. For more information on the ThetaHealing® Meditation Technique please visit ThetaHealing.com or the link on the top of my home page.
We started by renting a 4 person raft at Barber Park in SE Boise near my house. Some young men brought the raft out from a storage garage on to the lawn near the sales booth. The four of us – Cathy, my daughter, Pip and me – carried the raft from the lawn to the edge of the river where we launched the raft from a set of concrete stairs set into the sandy bank of the river. The Boise River is magical because it is clear and you can see the river rocks clear to the bottom in most places. It's cool water formed partially from the snow melt in the mountains. Our instructions from the woman who rented us the raft were to stay in the middle of the river, go down the diversion dams facing forward and to get out at the designated spot near Anne Morrison Park in downtown Boise.
As we floated the river, Pip marveled at the clarity of the water. In New Zealand, the run-off from cattle and pesticides prevents people from being able to safely recreate in the water. I realized I have been taking a lot for granted in Boise with the pristine river. We floated in the current mostly, but had to be strategic about where to go over the 3 diversion dams. It, honestly, was a little frightening but we handled it well and made it over all three without issue.
The new learning is really the point of this post. I've kayaked and paddle boarded before many times, and even in some precarious situations. There was a time kayaking in Lake Michigan that they pulled everyone off the lake because the wind created dangerous waves right after we pulled our kayaks up onto the beach. I've paddle boarded in heavy winds that made me spin in circles until I had to sit down to lower the wind drag to be able to steer. This is all to say that while I am a long way from being a paddling expert, I basically know what I'm doing.
Cut to the experience floating a raft down the Boise River with Mya, Pip and Cathy. There is a *big* difference between steering a raft and steering a paddle board or kayak. For starters, there is no fin on the bottom of a raft to be able to help with steering. The other thing that separates a raft from the kayak or paddle board is that it doesn't sit in the water as much as on the water. Both of these make paddling very different. I learned a lot even though it wasn't my first time down the river.
The last 9 months have been difficult, that's the reason you haven't heard much from me. But things are on the right course and all is well. Still… I've been very open to learning things from all of my experiences. This experience with a raft did not disappoint! I learned so much about rafting and paddling, but the really cool thing is that everything I learned can be applied not only to rafting, but applied to life. It crystalized in my mind in such a way that I really wanted to share it with you.
Go with the flow. When we first started, we were working pretty hard. We corrected angles trying to avoid the trees along the sides and the rocks over the diversion dams. Often we didn't correct angles as much as overcorrect angles by our paddling. We even spun circles a few times! We quickly learned that most often the current would take us where we needed to be without any intervention (ahem… paddling) from us. This is also true in life. No job change on the horizon after sending out lots of resumes? Maybe it's time to double down on the job you have. Struggling with a decision to sell your house or not? Maybe just give yourself room to not decide for a while. Sometimes when we go in the directions we are being moved without fighting, it makes everything easier. The more we lean into trusting the Universe, the more we begin to believe the universal current really is taking care of us. This takes trust.
The evidence of your right actions does not immediately appear, this doesn't mean nothing is happening. Occasionally, we really did have to paddle to change our angle to avoid sharp rocks in the center of a diversion dam or large branches on the edge. We learned that there in the faster current there is a 30 second-1 minute delay in the rafts response to the paddling. We needed to paddle and then watch, paddle and watch. We worked really hard when we tried paddling non-stop and we made a lot more work for ourselves by overcorrecting. Life is like this as well. We can't see evidence of our actions right away in most cases. This doesn't mean nothing is happening. You won't see weight loss after one day of health eating, you won't be able to retire after you save $100 one time, and you won't grow your hair long the day you decide it needs to be different. These things take time. We need to take the right actions and then give the results time to appear.
Change can be hard. When we approached the raft take out at Anne Morrison Park, we all talked about how fun the trip down the river had been. We experienced lots of natural beauty, the fresh water, tons of ducks swimming along beside us, the sun shining and the light breeze blowing. We were a little stiff from sitting for 2 hours and even though we were ready to stand up, getting out of the raft was a transition. None of us were really ready to leave the water. In fact, once we pulled the raft out of the river, we all waded back in to stand in the cool water for a few more moments feeling the water against our ankles and calves. We knew we weren't going to stay on the river past that point, our bodies were ready to be out of the sun and standing on land and yet we definitely felt the transition. Change can be hard, even good change. If you are experiencing change (if you are human, this is you) be gentle on yourself. Give yourself time to stand in the metaphorical cool water and then be willing to take those first difficult steps up the sandy shore to stand on dry land. As soon as you get to the dry land, your mind and body are more ready for the transition and you will begin to move more easily. The same can be said of our lives. When we are faced with change, good or bad, be gentle with ourselves. Allow ourselves time to process the change without judging ourselves. Walk slowly taking time to stretch and then walk on knowing each step gets easier.
I'm looking forward to being back with you more regularly now that I have faced some changes in my own life I wasn't ready for. This is the first blog post I've posted without my dear chihuahua, Stella sitting either on my lap or at my feet. Here is to you, Stella Bella!
All my love to you my dear readers. If this has been helpful or meaningful to you, please consider liking or sharing.


Lauren Connors & Christina Carter -- Mirrors 1 -- Meditations of the ascension of Blind Joe Death.
Mike Cooper -- Death Letter -- Oh Really!
Elizabeth Cotten -- Live at Euphoria Tavern -- Elizabeth Cotten/ Marisa Anderson 7"


The IRS and U.S. Treasury last week issued long-awaited guidance on a new tax break introduced by the Tax Cuts and Jobs Act (TCJA) that may provide real estate and other investors with significant tax savings. While the proposed regulations provide some clarity about the Opportunity Zone program and how it will be administered, many questions remain unanswered and will require further guidance from the IRS and the Treasury. As a result, it is critical that taxpayers tread very carefully with the counsel of experienced advisors and accountants.
Congress created the Opportunity Zones program as an incentive to help revitalize distressed neighborhoods with private investment rather than federal spending dollars. Under the hurriedly drafted tax reform bill passed into law at the end of 2017, taxpayers may defer and potentially eliminate capital gains tax liabilities from the sale of certain assets when they reinvest those gains into predominantly low-income areas certified by the U.S. Treasury as Opportunity Zones (OZs).
The law makes it clear that taxpayers may not invest directly into businesses or development projects in OZs. Rather, they must direct their capital into Qualified Opportunity Funds (QOFs) organized as corporations and partnerships, which in turn must invest at least 90 percent of their assets, directly or indirectly, into qualified businesses and real estate assets located in designated OZs. The QOFs, which are already being created by developers, private equity firms and even nonprofits, are made up of a portfolio of buildings and businesses located in more than 8,700 census tracts across the country that the Treasury has certified as Opportunity Zones.
How can I Reap Tax Savings?
Avoid capital gains tax on the appreciation of QOF investments held for a minimum of 10 years by making an election to increase the basis of the QOF investment to the fair market value of the investment on the date they sell their interest in the QOF.
For example, consider an investor who sells a property and incurs a $1 million capital gain. If the investor rolls that gain into a QOF, he or she can defer paying taxes on that gain until 2026. If the investor holds the interest in QOF for seven years, he or she will be taxed on only 85 percent of the original gain, or $850,000, instead of $1 million. If the investor sells his or her interest in the QOF after 10 years, his or her basis increases, and he or she pays no tax on the appreciation of the QOF investment.
From an investor's standpoint, qualified opportunity funds can be good alternatives to 1031 like-kind exchanges, especially if taxpayers have challenges satisfying the 1031 requirements to identify suitable replacement property within 45 days and close within 180 days. Also, because the new tax law limits the use of 1031 exchanges solely to real estate beginning in 2018, investing in QOFs may be the only way for some investors to defer paying tax on their capital gains until 2026.
Nevertheless, investors should recognize that QOFs are illiquid investments that yield the most rewards the longer investors hold onto them. Moreover, there is no guarantee that investments in distressed Opportunity Zones will appreciate in value. Therefore, investors seeking to capitalize on the tax-deferred treatment of gains invested into QOFs should be prepared to hold onto their QOF investments for a long-term and have other sources of liquidity available to them (e.g., to cover tax payments on the capital gains they will recognize in 2026).
The guidance issued by the Treasury and IRS on Oct. 19, 2018, is not a comprehensive list of rules that answer all of taxpayers' questions concerning the Opportunity Zones program. In fact, the Treasury and the IRS are still working on additional guidance that is expected to address a number of other issues and questions posed by tax practitioners. Nonetheless, these proposed regulations provide some much-needed clarity regarding the requirements that taxpayers must meet in order to properly defer the recognition of gains by investing in QOFs, as well as certain requirements that corporations or partnerships must meet in order to qualify as a QOF. Taxpayers may now rely on these proposed regulations to help them implement tax-efficient planning strategies for the remainder of 2018 and into 2019. Following are some of the issues that the most recent government guidance addresses.
What Gains are Eligible for Tax Deferral?
Capital gains incurred from an actual or deemed sale or exchange of assets, or any other gains that are required to be included in a taxpayer's computation of capital gain are eligible for deferral. Excluded are gains that arise from a sale or exchange of property with a related party (based on the 20 percent ownership rule).
Who Can Qualify for Tax Deferral?
Taxpayers that can elect tax-deferral benefits of the Opportunity Zone program include individual taxpayers, C corporations (including regulated investment companies (RICs) and real estate investment trusts (REITs)), partnerships and certain other pass-through entities (including S corporation, decedents' estates, and trusts). Partnerships may elect to defer all or part of their capital gain to the extent they make an eligible investment in a QOF. If a partnership does not elect to defer capital gain, its partners may elect their own deferral with respect to their distributive share of capital gain to the extent they make an eligible investment in a QOF. Similar rules apply to other pass-through entities (including S corporations, estates and trusts) and their shareholders and beneficiaries.
When does the 180-day Period Begin?
Taxpayers generally must roll over capital gains into a QOF within 180 days from the date of sale or exchange giving rise to the capital gain. The proposed regulations provide that, in certain circumstances, the 180-day clock does not start running until the date the ultimate taxpayer would be deemed to have recognized the gain. For example, the 180-day period for partners in partnerships and shareholders of S corporations generally begins on the last day of the entity's taxable year. The proposed regulations, however, provide an alternative for situations in which the partner knows (or receives information) regarding both the date of the partnership's capital gain and the partnership's decision not to elect deferral of the gain, in which case the partner may choose to begin its own 180-day period on the same date as the start of the partnership's 180-day period. Similar rules apply to other pass-through entities (including S corporations, estates and trusts) and their shareholders and beneficiaries.
What Qualifies as an Eligible Interest Investment in a QOF?
In order to defer capital gains tax under the Opportunity Zones program, taxpayers must own an eligible interest in a QOF, which is an equity interest issued by the QOF, including preferred stock or a partnership interest with special allocations. Specifically excluded from the definition of eligible interest investment are debt instruments, such as bonds, loans or other evidence of indebtedness, as well as deemed contributions of money due to increase in partner's allocable share of partnership's liabilities.
What is included in the Definition of Qualified Opportunity Zone Business Property?
A QOF must be an investment vehicle legally structured as a corporation or partnership in any of the 50 states, D.C. or five U.S. territories. It must invest at least 90 percent of its assets in qualified opportunity zone property (QOZ Property), which includes qualified opportunity zone business property (QOZ Business Property) and certain equity interests in operating subsidiaries (either corporations or partnerships) that satisfy certain additional QOZ business requirements.
QOZ Business Property is generally tangible property that the QOF purchased from an unrelated party after Dec. 31, 2017, and used in the QOFs trade or business (substantially all of the use of such property must be in a qualified opportunity zone). The original use of such property must begin with the QOF (e.g., new construction), or the QOF must make substantial improvements to the property within 30 months of the date of its acquisition.
By and large, for the "substantial improvement" requirement to be satisfied, additions to the basis of the purchased tangible property in the hands of the QOF must exceed an amount equal to the QOF's adjusted basis of such property at the beginning of the 30-month period. Based upon IRS guidance, if a QOF purchases a building located on land wholly within a QOZ, substantial improvement to the purchased tangible property is measured by the QOF's additions to the adjusted basis of the building (thus, the "original use" requirement is not applicable to the land and the QOF is not required to separately substantially improve the land on which the building is located).
The proposed regulations also establish a helpful "working capital" safe harbor for QOF investments in QOZ businesses that acquire, construct, or rehabilitate tangible business property used in a business operating in an opportunity zone. Under this safe harbor, a qualified opportunity zone business may hold cash or cash equivalents for a period of up to 31 months, if there is a written plan that identifies these working capital assets as held for the acquisition, construction, or substantial improvement of tangible property in the opportunity zone, there is a written schedule showing that the working capital assets will be used within 31-months, and the business substantially complies with the schedule.
There's no question that Opportunity Zones have the potential to yield immense tax benefits. However, since the regulations are complex and still evolving, investors and QOF sponsors will need to work closely with their tax and legal advisors to plan ahead and implement strategies that maintain compliance and maximize tax savings under application of the new law.


text:
\section{Introduction}

Short-duration gamma ray bursts (SGRBs) are commonly believed to be powered by rapid accretion onto a rapidly-spinning black hole, following the coalescence of a compact binary system (e.g.~\citealt{Narayan+92}).  The latter may be comprised either of two neutron stars (NS-NS) or a neutron star and a stellar-mass black hole (NS-BH).  The recent discovery of an SGRB \citep{LIGO+17Fermi} coincident with the gravitational wave event GW170817 \citep{LIGO+17DISCOVERY}, as well as non-thermal emission from the off-axis afterglow of a relativistic jet (e.g.~\citealt{Hallinan+17,Alexander+17,Margutti+17,Troja+17,Haggard+17}), provided compelling evidence that at least some SGRBs arise from NS-NS mergers \citep{Blinnikov+84,Paczynski86,Goodman86,Eichler+89}.  Although no NS-BH binaries are currently known, they are theoretically predicted to exist and may also give rise to SGRB emission in cases where the merger results in the creation of an accretion disk (e.g.~\citealt{Rosswog05,Kyutoku+11,Foucart+13,Foucart+14,Foucart+16,Paschalidis+15,Bhattacharya+18}).  This latter condition requires that the BH be of sufficiently low mass and/or rapidly spinning in the prograde direction with respect to the binary orbit, such that the NS will be tidally disrupted before falling into the BH horizon (e.g.~\citealt{Foucart12}).

At least $\sim$ 20\% of SGRBs are followed by temporally-extended X-ray emission, which lasts $\sim 10-1000$ s or longer after the initial prompt gamma-ray burst (\citealt{Norris&Bonnell06,Gehrels+06,Perley+09,Norris+10,Minaev+10,Kaneko+15,Kisaka+17,Burns+18}); Fig.~\ref{fig:lc_grbee} shows the light curves in two clear cases.  This ``extended emission'' is too luminous and time variable to be synchrotron afterglow emission generated as the GRB jet interacts with the interstellar medium.  Instead, it likely results from ongoing activity (e.g.~prompt energy release in the form of a relativistic jet) from the central compact object remnant left by the merger (however, see \citealt{Eichler+09,Eichler17} for an alternative interpretation).

Several models have been proposed for the engine behind the extended emission.  These include the electromagnetic spin-down of a long-lived millisecond magnetar generated from a NS-NS merger (e.g.~\citealt{Metzger+08,Bucciantini+12,Rowlinson+13,Gao+13,Gompertz+14,Gibson+17}).  While this model remains in contention, the lack of late-time radio detections of short GRBs is beginning to place constraints on the amount of rotational energy released from such magnetar remnants \citep{Metzger&Bower14,Horesh+16,Fong+16}.  A stable magnetar is also disfavored in GW170817 by the relatively weak afterglow \citep{Margutti+18,Pooley+18} and the red colors of the late kilonova emission indicative of black hole formation \citep{Metzger&Fernandez14}; however, no extended prompt emission was observed in this event \citep{LIGO+17Fermi}.

Another possibility is that the extended emission is powered by late-time accretion ("fall-back") onto the black hole of tidal matter which is marginally bound to the system after the merger event \citep{Rosswog07}.  However, a glaring issue with this model are the observed evolution of the extended emission light curves.  The rate of mass fall-back after the merger, which is generally taken as a proxy for engine activity, is usually predicted to follow an uninterrupted power law, $\dot{M} \propto t^{-5/3}$, starting from very early times $\lesssim 0.1$ s after the merger.  This result follows from a distribution of ejecta mass with energy, $dM/dE \propto E^{\alpha}$ that is relatively flat ($\alpha \approx 0$) around $E = 0$ (\citealt{Rees88}).  Fig.~\ref{fig:lc_grbee} shows that a single power-law decay is incompatible with observed extended emission light curves, which generally show a lull and delay until peak of a few to tens of seconds after the initial gamma-ray burst.  Explanations proposed for this behavior include a transition in the jet launching mechanism from neutrino-driven to MHD-powered \citep{Barkov&Pozanenko11}, or differences in the rate of accretion of mass versus magnetic flux \citep{Tchekhovskoy&Giannios15,Kisaka&Ioka15}, as the latter controls the jet power in the Blanford-Znajek process (however, \citealt{Parfrey+15} argue that a jet may be produced even in the absence of net magnetic flux).

Studies of fall-back accretion in neutron star mergers also generally neglect a robust physical process:
the dynamical influence of radioactive heating by heavy nuclei synthesized by rapid neutron captures ($r$-process) in the decompressing material \citep{Metzger+10a}.  This same heating within the unbound debris is responsible for powering the "kilonova" emission \citep{Li&Paczynski98,Metzger+10} days to weeks after the merger, as was observed following GW170817 (e.g.~\citealt{Coulter+17,Soares-Santos+17,Cowperthwaite+17,Drout+17}).  However, at earlier times, less than a few seconds following mass ejection from the merger, the $r$-process heating rate is orders of magnitude higher.  Energy released by the $r$-process does not qualitatively alter the dynamics of the bulk of the {\it unbound} ejecta \citep{Rosswog+14}. However, it can increase the quantity of ejecta and critically shape the dynamics of the {\it marginally bound} ejecta responsible for fall-back accretion, particularly on the second to minute timescales of relevance to the observed extended emission \citep{Metzger+10a}.

Depending on the electron fraction of the ejecta, $Y_{e} \sim 0.02-0.3$, the $r$-process releases a total energy of $Q_{\rm tot} \sim  1-3$ MeV per nucleon, mostly through beta-decays, at an approximately constant rate over a characteristic heating timescale $t_{\rm heat} \sim 1$ s following ejection (see~Fig.~\ref{fig:heating_rate}).  Then, at times $t \gg t_{\rm heat}$ (e.g. relevant to the kilonova), the heating rate approaches an asymptotic power-law decay $\dot{q} \propto t^{-1.3}$ \citep{Metzger+10}.  A nucleon (mass $m_n$) which is marginally gravitationally bound to the black hole of mass $M$, on an orbit of energy per nucleon $|E_{\rm tot}| = GMm_n/2a$ and semi-major axis $a$ (under the approximation of Newtonian gravity), returns to the hole and circularizes into the accretion disk on a timescale given by its orbital period,
\begin{eqnarray}
t_{\rm orb} = 2\pi\left(\frac{a^{3}}{GM}\right)^{1/2}
 \approx 1.6\,{\rm s}\left(\frac{|E_{\rm tot}|}{1\,{\rm MeV}}\right)^{-3/2}\left(\frac{M}{5M_{\odot}}\right)
\label{eq:torb}
\end{eqnarray}
This expression reveals several important facts.  First, the total energy available from the $r$-process, $Q_{\rm tot}$, exceeds the binding energy of orbits with fall-back times comparable to observed extended emission after SGRBs ($\gtrsim 10$ s; Fig.~\ref{fig:lc_grbee}); including the effects of $r$-process heating is thus crucial to determining the late-time fall-back rate \citep{Metzger+10a}.  Also of interest is the apparent coincidence that the fall-back time of matter with energy $|E_{\rm tot}| \sim Q_{\rm tot}$ is comparable to the timescale $t_{\rm heat} \sim 1$ s over which the bulk of the heating occurs.  This means that different parts of the debris could receive different amounts of the total available heating, depending on their fall-back time.  \citet{Metzger+10a} show that this can imprint a more complex mass fall-back evolution than the standard $\propto t^{-5/3}$ decay, instead generating either temporal gaps of several seconds or sharp cut-offs in the fall-back rate after a certain time, depending on the ratio of $t_{\rm orb}(|E_{\rm tot}| = Q_{\rm tot})$ and $t_{\rm heat}$.

In this paper we apply the model of \citet{Metzger+10a} in order to estimate the effects of $r$-process heating on the energy distribution of the merger ejecta and its resulting mass fall-back rate, using for the first time initial conditions for the debris properties taken directly from a numerical relativity simulation of a NS-BH merger \citep{Foucart+16}.  We also explore what effects the $Y_e$-dependent nuclear heating rate has, given a realistic spread in the debris properties, on the predicted range of fall-back behavior.  In \S~\ref{sec:model} we describe the problem setup, our treatment of the nuclear heating, and the numerical technique. In \S~\ref{sec:results}, we present our results for the mass fall-back rate.  Finally, in \S~\ref{sec:discussion} we map our findings onto mergers leaving BHs of different mass scales to demonstrate how NS-NS and NS-BH mergers might in principle be distinguished based on the properties of their late-time X-ray light curves.

\begin{figure}
  \begin{center}
  \includegraphics*[width=.5\textwidth]{lc_plot}
  \caption{{\it Swift} BAT X-ray light curves of two SGRBs, GRB080503 \citep{Perley+09} and GRB 060614 \citep{Gehrels+06}, which show their temporally-extended prompt emission.  Both cases show remarkably similar light curves, which peak on a timescale $\sim 30$ s after the prompt SGRB spike of duration $\lesssim 2$ s (gray region; not shown at the chosen time binning).  The lull in emission from $t \sim 2-30$ s contrasts with the naive expectation that the X-ray luminosity track the $\propto t^{-5/3}$ mass fall-back accretion (shown for comparison with a pink line).}
  \label{fig:lc_grbee}
  \end{center}
\end{figure}

\begin{figure}
  \begin{center}
  \includegraphics*[width=.5\textwidth]{HeatingRate}
  \includegraphics[width=0.48\textwidth]{initial_ye_qtot}
  \caption{{\bf Top:} Nuclear heating rate of the unbound debris as a function of time since ejection (blue lines), calculated for $\sim$250 separate fluid elements from the NS-BH merger simulation M7\_S8 \citep{Foucart+14} using the SkyNet nuclear reaction network \citep{Lippuner+17}. We have reduced the heating rate from the rate of nuclear energy by a fraction $(1-f_{\nu}) = 0.55$ to account for fraction of the $\beta-$decay energy carried away by neutrinos (eq.~\ref{eq:Qtot}). A black line shows the step-function approximation employed in our fall-back model (eq.~\ref{eq:qdot}), where in this example $Q_{\rm tot}= 3$ MeV and $t_{\rm heat}= 1$ s.  {\bf Bottom:} Total heating rate $Q_{\rm tot}$ for the same fluid elements as a function of their electron fraction $Y_{e}$.  Shown for comparison is the analytic estimate from equation (\ref{eq:Qtot}), for fixed values of the parameters $\bar{A}/\bar{Z} = 2.4$, $f_{\nu} = 0.45$, $\left( \frac{B}{A} \right)_s=8.7$ MeV nuc$^{-1}$ and $\left( \frac{B}{A} \right)_r= 8$ MeV nuc$^{-1}$.  }
  \label{fig:heating_rate}
  \end{center}
\end{figure}

\section{Model}
\label{sec:model}
\subsection{Numerical Simulation Data}
We use 3D position/velocity data taken from the grid points of the NS-BH merger simulation ``M5-S7-I60'' performed by \citet{Foucart+16} using the numerical code SpEC\footnote{The Spectral Einstein Code: \url{http://www.black-holes.org/SpEC.html}} \citep{Kidder+00}.  This simulation implemented the DD2 Equation of State \citep{Hempel+12} for a $1.4~M_{\odot}$ NS, and included a neutrino leakage scheme, as implemented in \citet{Deaton+13}. The initial mass of the BH is $M_{i} \simeq 5~M_{\odot}$. This is a precessing system, with a dimensionless spin of $\chi = 0.7$ on the BH, prograde but misaligned by $60^\circ$ with respect to the orbital angular momentum.  The final mass of the BH after the merger is $M = 6.11 M_{\odot}$.

We extract data on the ejecta tidal tail at a time $t =$15 ms after merger.  These are then used as initial conditions in post-processing analysis, in which we evolve the fluid elements further as non-interacting Lagrangian particles.  Because initial energies, positions and velocities used in our analysis were derived from a general relativistic simulation, they are inconsistent with the Newtonian expression for total energy. We therefore rescale the initial velocities from the simulations ($\vec{v}_{\rm GR}$) to their Newtonian equivalent according to $\vec{v}_{\rm N}=\frac{\vec{v}_{\rm GR}}{|\vec{v}_{\rm GR}|}|\vec{v}_{\rm N}|$, where
\begin{eqnarray}
\frac12 m_n{|\vec{v}_{\rm N}|}^2 - \frac{GMm_n}{r} ={} E_{\rm tot},
\label{eq:rescale}
\end{eqnarray}
and $E_{\rm tot} = -m_n(u_t+1)$ is an estimate of the specific binding energy (per nucleon) of the test particle, assuming geodesic motion in a time-independent spacetime, and $r$ is the distance from the BH.

\begin{figure}
\begin{center}
\includegraphics*[width=.5\textwidth]{initial_ye}
\caption
{Mass-weighted distribution of the tidal tail ejecta, extracted from the NS-BH merger simulation data at $t = 15$ ms post-merger, in the space of initial energy, $E_{\rm tot}$, and electron fraction, $Y_{e}$.  A dashed line at $E_{\rm tot} = 0$ separates the debris which is initially bound versus unbound to the black hole.  Fluid elements above the solid blue line could be unbound due to $r$-process heating along if the ejecta receives the total available heating, $Q_{\rm tot} \sim 3$ MeV (Fig.~\ref{fig:heating_rate}, bottom panel).}
\label{fig:ye_u}
\end{center}
\end{figure}

Fig.~\ref{fig:ye_u} shows the distribution of initial ejecta properties as a function of $E_{\rm tot}$ and electron fraction $Y_e$, weighted by mass.  Most of the debris is neutron-rich, with an electron fraction $Y_{e} \lesssim 0.05$.  A dashed line separates ejecta which is initially gravitationally bound ($E_{\rm tot} \ge 0$) from unbound material ($E_{\rm tot} \le 0$).  Of the total mass $0.116 M_{\odot}$ of the tidal ejecta, approximately $1.23 \times 10^{-2} M_{\odot}$ is unbound.  Even if they are initially bound to the black hole, fluid elements above the solid blue line could in principle gain sufficient heating from the $r$-process (Fig.~\ref{fig:heating_rate}, bottom panel) during their orbit to become unbound.  As we discuss later, depending on the timescale over which the $r$-process heating is released, matter near this line can also remain bound but fall back to the black hole at a later time than had it experienced zero heating.

\subsection{R-Process Heating}
\label{sec:heating}

We include the effects of $r$-process heating on the trajectories of the fall-back debris in a post-processing step, similar to the model employed by \citet{Metzger+10a}.  The total nuclear energy released as neutrons are captured onto seed nuclei during the $r$-process is approximately given by the difference between the initial and final nuclear binding energies,
\begin{eqnarray}
Q_{\rm tot} \simeq (1-f_{\nu})\left[ \left( \frac{B}{A} \right)_r - X_s \left(\frac{B}{A} \right)_s - X_n \Delta_n \right] \label{eq:Qtot},
\end{eqnarray}
minus the fraction $f_{\nu}$ of energy lost to neutrino emission ($f_{\nu} \approx 1/2$ at early times of interest).  Here $X_s = \bar{A} Y_e/\bar{Z}$ is the mass fraction of seed nuclei of average atomic mass number
$\bar{A}$ and charge $\bar{Z}$; $\left( \frac{B}{A} \right)_s=8.7$ MeV nuc$^{-1}$ and $\left( \frac{B}{A} \right)_r= 8$ MeV nuc$^{-1}$ are the average binding energies of seed and final r-process nuclei, respectively; $X_n=1-X_s$ is the neutron mass fraction; and $\Delta_n = (m_n-m_p)c^2= 1.293$ MeV is the neutron-proton mass difference.  For typical values $Y_{e} \approx 0.05$ (Fig.~\ref{fig:ye_u}), $\bar{A} \approx 90$, $\bar{Z} = 38$, $f_{\nu} = 0.45$, we find $Q_{\rm tot} \approx 3$ MeV, consistent with the results of SkyNet nuclear reaction calculations (bottom panel of Fig.~\ref{fig:heating_rate}).

As shown in the top panel Fig.~\ref{fig:heating_rate}, the $r$-process heating in freely-expanding unbound debris is approximately constant for a timescale of $t_{\rm heat} \sim 1$ s, when most of the total energy is released, before rapidly entering a power-law decline.  We approximate this behavior by a function of the simple form,
\begin{equation} \label{eq:qdot}
\dot{q} =
\begin{cases}
Q_{\rm tot}/t_{\rm heat}, \hspace{2cm} \text{if\,\,\,}t \le t_{\rm heat} \,{\rm and}\, v_{r} > 0
\\
0,  \hspace{2cm} \text{if\,\,\,}t > t_{\rm heat}  \,{\rm or}\, v_{r} < 0,
\end{cases}
\end{equation}
where $v_{r}$ is the radial velocity of the fluid element and the values of $Q_{\rm tot} \sim 3$ MeV and $t_{\rm heat} \sim 1$ s are parameters which we allow to vary modestly about these fiducial values.

The $r$-process heating, as described by equation (\ref{eq:qdot}), is assumed to terminate if and once matter starts to return to the black hole ($v_{r} < 0$), for reasons we now discuss.  Although the heating rate evolution shown in Fig.~\ref{fig:heating_rate} was calculated for unbound debris, this behavior is a good approximation also for bound debris during its initial outwards motion.  However, the heating is abruptly suppressed once matter reaches apocenter and begins to return to the black hole \citep{Metzger+10a}.  As matter undergoes re-compression, its temperature rises adiabatically and the $r$-process path (which is determined at fixed $Z$ by the equilibrium between neutron capture $(n,\gamma)$ and photodissociation $(\gamma,n)$ processes) is driven closer to the stable valley, where the $\beta-$decay timescales, and thus neutron consumption and energy release timescale, becomes much longer.  \citet{Metzger+10a} show that to good approximation the heating rate effectively shuts off once $v_{r} < 0$, motivating us to neglect heating entirely during re-compression.

\begin{figure}
  \begin{center}

  \includegraphics*[width=.48\textwidth]{trajectories}

  \caption
  {Schematic illustration of the tidal ejecta from NS-BH or NS-NS mergers, comparing the fluid element trajectories with (dashed lines) and without (solid lines) the effects of $r$-process heating.  The orbital streams are highly elliptical, such that pressure gradients $\nabla P$ point almost radially outwards and energy released from the $r$-process is transferred quickly (on the expansion timescale) into ejecta kinetic energy.  The trajectories of tightly bound ($E_{\rm tot}\ll 0$) or strongly unbound ($E_{\rm tot}\gg 0$) matter are not greatly altered.  However, marginally bound material with $E_{\rm orb} \gtrsim -Q_{\rm tot}$ and orbital periods comparable to the timescale of the $r$-process experiences preferential heating relative to more tightly bound debris.  This opens a gap in the orbital energy distribution and a temporal gap or late-time cut-off in the mass fall-back rate.}
\label{fig:schematic}
  \end{center}
\end{figure}

\begin{figure}
  \includegraphics[width=0.5\textwidth]{all_fallbacks}
  \includegraphics[width=0.5\textwidth]{dMdE}

  \caption{{\bf Top Panel:} Mass fall-back rate, $\dot{M}$, as a function of time, $t_{\rm fb}$, after the NS-BH merger, calculated for different assumptions regarding the total $r$-process heating experienced $Q_{\rm tot}$ and its characteristic duration $t_{\rm heat}$.  Each case is labeled according to the general behavior of the light curve, i.e.~whether heating introduces a temporal gap, or a complete cut-off, in the late-time fall-back rate.  {\bf Bottom Panel:} Distribution of the debris mass with energy, $dM/dE$, comparing the initial distribution after the dynamical phase of the merger to that imprinted by $r$-process heating, shown for the same models and color schemes used in the top panel.  $r$-process heating opens a gap in the energy distribution, which in turn results in either a temporal gap or a complete cut-off in the fall-back rate, depending on whether the energy gap overlaps with $E_{\rm tot} = 0$.}
  \label{fig:fallback}
\end{figure}

\begin{figure*}
  \begin{center}
  \includegraphics[width=1.0\textwidth]{param}

  \caption
  {Regimes of the impact of $r$-process heating on fall-back accretion in the space of the total nuclear released energy, $Q_{\rm tot}$, and the timescale of the heating, $t_{\rm heat}$.  The value of $Q_{\rm tot}$ (left vertical axis) is mapped onto the initial electron fraction $Y_e$ (right vertical axis) using eq.~(\ref{eq:Qtot}) as shown in the bottom panel of Fig.~\ref{fig:heating_rate}.  A 2D colored histogram shows the mass distribution of the ejecta in ($Q_{\rm tot}, t_{\rm heat}$), calculated by mapping the ejecta properties of our simulation for a NS-BH merger ($M \simeq 6M_{\odot}$) into the $r$-process heating trajectories from SkyNet calculations (Fig.~\ref{fig:heating_rate}).  Symbols show the results of our parameter study in which we assume a BH mass $M \approx 6M_{\odot}$ and that all fluid elements experienced heating characterized by fixed values of $Q_{\rm tot}$ and $t_{\rm heat}$ according to eq.~\ref{eq:qdot} (see Fig.~\ref{fig:fallback} for a few examples).  Crosses denote cases which result in a complete cutoff in the fall-back rate after a given time, while circles show cases in which a temporal gap is opened in the fall-back curve (the duration of the gap is denoted both by the radius and color of the circle using the legend given on the right).  Lines represent the critical condition ($\eta = \eta_{\rm c} \approx 0.95$; eq.~\ref{eq:eta}) giving rise to a long ($\sim 30$ s) gap for different values of the mass of the central black hole as marked, ranging from $M \approx 2.5M_{\odot}$ relevant to NS-NS mergers to $M \sim 6-20M_{\odot}$ relevant to NS-BH mergers.  While the tidal ejecta from NS-NS mergers lies in the cut-off regime ($\eta \gg 1$) for neutron-rich ejecta $Y_e \lesssim 0.2$, the NS-BH merger case resides close to the gap regime ($\eta \sim \eta_{\rm c} \approx 0.95$).}
  \label{fig:param}
  \end{center}
\end{figure*}

\subsection{Numerical Model}

At early times after the merger, the ejecta is dense and highly opaque to photons, such that all of the $r$-process heating (other than that which escapes as neutrinos) goes into internal thermal energy.  The fluid element orbits of interest possess high eccentricities $e$, where
\begin{equation} 1-e = \frac{r_{\rm p}}{a} \approx 0.03\left(\frac{r_{\rm p}}{5r_{\rm g}}\right)\left(\frac{|E_{\rm tot}|}{3{\rm MeV}}\right). \end{equation}
Here we have normalized the pericenter radius of the debris, $r_p$, to the gravitational radius of the BH, $r_{\rm g} = GM/c^{2}$.  Temperature and density gradients in the ejecta are thus directed nearly radially outwards, such that the $r$-process energy will be transferred through PdV work into ejecta kinetic energy on the local expansion timescale.  Fig.~\ref{fig:schematic} shows a schematic illustration of the influence of $r$-process heating on the trajectories of different fluid elements.

Following explicitly the effects of $r$-process heating on the debris dynamics would require a three-dimensional hydrodynamical simulation across a large dynamical range in radius.  However, given the highly supersonic expansion velocities of the ejecta, such a treatment is not necessary, as the main effect of the heating is a local slow acceleration of the ejecta along the local pressure gradient radial direction and thus the adiabatic conversion of the injected thermal energy to kinetic energy.  Starting with fluid element velocities rescaled from the simulation data (eq.~\ref{eq:rescale}), we directly increase the kinetic energy of the $i$th element according to
\begin{equation}
\frac{d}{dt}\left(\frac{1}{2}m_n v_{r,i}^{2}\right) = \dot{q}_i,
\end{equation}
where $\dot{q}_i$ follows equation (\ref{eq:qdot}). For each fluid element, we follow its 3D trajectory until either it reaches periapse, which we define as the fall-back time $t_{\rm fb}$, or once the simulation terminates. We then record $t_{\rm fb}$ for all bound material and use the total mass in different bins of $t_{\rm fb}$ to calculate the fall-back accretion rate.

\section{Results for Mass Fall-Back}
\label{sec:results}

The top panel of Figure \ref{fig:fallback} shows examples of the fall-back accretion rate as a function of time after the merger.  In this initial analysis, for each model we assume that all fluid elements experience $r$-process heating rate (according to eq.~\ref{eq:qdot}) characterized by the same total amount $Q_{\rm tot}$ and characteristic duration, $t_{\rm heat}$.  The bottom panel of the figure shows the final energy distribution of the ejecta mass for the same models as compared to the initial energy distribution.

When $r$-process heating is neglected ($Q_{\rm tot} = 0$), the roughly flat energy distribution $dM/dE \approx constant$ around $E_{\rm tot} = 0$, as imparted by the dynamical phase of the merger, is unaltered and the fall-back rate follows the canonical prediction of an uninterrupted $\dot{M} \propto t^{-5/3}$ decay.  By contrast, including the effects of $r$-process heating for values of $Q_{\rm tot} \sim 1-3$ MeV and $t_{\rm heat} \sim $ 1 s drastically changes the energy distribution around $E_{\rm tot} \approx 0$ and results in a more complex fall-back history.  In particular, there are two possible outcomes in shape of the fall-back curve: either an absolute cut-off after some time (e.g. as in the $Q_{\rm tot} = 2$ MeV, $t_{\rm heat}$ = 2 s case), or a cut-off followed by re-emergence of fall-back, i.e.  a "gap" (e.g. as in the $Q_{\rm tot} = 1.5$ MeV and $t_{\rm heat}$ = 1.5 s case).
As we now discuss, these qualitatively different behaviors can be understood by comparing the timescale over which the ejecta is heated to its orbital timescale (eq.~\ref{eq:torb}; see also \citealt{Metzger+10a}).

First consider the existence of a {\it critical} orbital period $t_{\rm orb,c}$, which corresponds to matter bound to the BH by an energy equal to the energy $\approx (Q_{\rm tot}/t_{\rm heat})t_{\rm orb}$ it receives from the $r$-process over the orbital period $t_{\rm orb}$ (when $t_{\rm orb} \lesssim t_{\rm heat}$).  Using equation (\ref{eq:torb}) for $t_{\rm orb}$, this gives
\begin{equation}
t_{\rm orb,c} \approx  0.62\,{\rm s}\left(\frac{Q_{\rm tot}}{3\,{\rm MeV}}\right)^{-3/5}\left(\frac{M}{5M_{\odot}}\right)^{2/5}\left(\frac{t_{\rm heat}}{\rm 1s}\right)^{3/5},
\label{eq:torbc}
\end{equation}
Ejecta which starts on an orbit of period $t_{\rm orb} \gg t_{\rm orb,c}$ always receives the full $r$-process heating before reaching apocenter (at which point the matter starts to re-compress and heating shuts off for reasons discussed earlier), while matter which starts very tightly bound ($t_{\rm orb} \ll t_{\rm orb,c}$) may receive only a fraction $t_{\rm orb}/t_{\rm heat}$ of the total heating (if $t_{\rm heat} \gtrsim t_{\rm orb,c}$).

Crucially, however, if $t_{\rm heat} \gtrsim t_{\rm orb,c}$ even matter with an initial $t_{\rm orb}$ which is slightly less than $t_{\rm orb,c}$ can {\it also receive the full heating} because, as the energy of a fluid element increases, its orbital period also grows, giving it more time to receive the full allotment of nuclear energy (in other words, the final value of $t_{\rm orb}$ diverges in a runaway process due to the $r$-process heating).  This preferential heating opens a gap in the energy distribution of the debris, which can result in an absolute cut-off in the accretion rate, or a temporal gap, depending on the location of the gap.

Whether such behavior is possible depends on whether the $r$-process heating indeed acts uniformly over the orbit, i.e. on a critical ratio:
\begin{equation}
\eta \equiv \frac{t_{\rm heat}}{t_{\rm orb,c}} \approx 1.6\left(\frac{M}{5M_{\odot}}\right)^{-2/5}\left(\frac{Q_{\rm tot}}{3\,{\rm MeV}}\right)^{3/5}\left(\frac{t_{\rm heat}}{1\rm s}\right)^{2/5}
\label{eq:eta}
\end{equation}
If $t_{\rm heat} \ll t_{\rm orb,c}$ ($\eta \gg 1$), then the heating is applied in a short burst uniformly to all fluid elements and there is no runaway (preferential heating) of fluid elements as discussed above.  In this case no significant energy gap is opened; $\dot{M}_{\rm fb}$ shows a slight dip around the time at which $t_{\rm orb} \sim t_{\rm heat} \sim 1$ s, but otherwise experiences no significant interruption of fall-back activity and $\dot{M}$ still approaches a power-law $\propto t^{-5/3}$ decay at later times.

If $t_{\rm heat} \gtrsim t_{\rm orb,c}$ ($\eta \gtrsim 1$) then an energy gap is opened in the debris.
If $t_{\rm heat} \gg t_{\rm orb,c}$ ($\eta \gg 1$), then only the most marginally-bound matter will receive enough heat to unbind before arriving at apocenter and the energy gap extends to $E > 0$.  This case produces an absolute cut-off in $dM/d|E|$ (and hence $\dot{M}_{\rm fb}$) for $|E_{\rm tot}| \lesssim E_{\rm c}$, where $E_{\rm c}$ is the energy of orbits of period $t_{\rm orb} = t_{\rm orb,c}$.

In intermediate cases for which $t_{\rm heat} \sim t_{\rm orb,c}$ ($\eta \sim 1$), a large gap is opened in the energy distribution of the debris, but now material with initial orbital periods $t_{\rm orb} \lesssim t_{\rm orb,c}$ remains marginally bound despite the extra energy it receives, thus opening up a large temporal gap in $\dot{M}_{\rm fb}$ (see Fig.~\ref{fig:schematic} for an illustration).  Specifically, we find that a critical value of $\eta = \eta_{\rm c} \approx 0.95$ is needed to generate a long cutoff of $\sim 30$ s, similar to the observed lulls in the SGRB extended emission light curves (Fig.~\ref{fig:lc_grbee}).  As we discuss later, the black hole mass-dependence of $\eta_{\rm c}$ may have implications for distinct fall-back behavior in NS-BH versus NS-NS mergers.

Fig.~\ref{fig:param} shows the results of a broader study of the outcomes of fall-back across the parameter space of $r$-process heating parameters $1 \le Q_{\rm tot} \le 4$ MeV and $0 \le t_{\rm heat} \le 3$ s.    Crosses denote runs resulting in cut-off behavior, while circles denote cases with gaps (with the duration of gap indicated by the size of the circle and its color, based on the key given on the right of the diagram).  To highlight the relevant region of parameter space we overlay with a colored histogram the mass-weighted distribution of ($Q_{\rm tot},t_{\rm heat}$), obtained by mapping the ejecta properties from our NS-BH simulation data into the parameters extracted from the SkyNet heating trajectories based on their $Y_e$ values (Fig.~\ref{fig:heating_rate}), where we define $t_{\rm heat}$ as the time at which the heating rate curve first decreases below half of its maximum value.  We also overlay with lines the condition $\eta = \eta_{\rm c}$ (eq.~\ref{eq:eta}) for different assumptions about the BH masses, ranging from low values $M \approx 2.5M_{\odot}$ relevant to the remnants of NS-NS mergers to higher values $M \sim 6-20M_{\odot}$ appropriate to NS-BH mergers.  This location of the crosses and circles relative to the $\eta = \eta_{\rm c}$ line for the BH mass $M \simeq 6 M_{\odot}$ corresponding to our simulation verifies the validity of this criterion as that responsible for separating cut-off from gaps in fall-back behavior.

\subsection{$Y_e$-dependent spread in fluid element heating}

\begin{figure}
  \begin{center}
  \includegraphics[width=0.48\textwidth]{ye_fallbacks}

  \includegraphics[width=0.48\textwidth]{skynet_fallback}

  \caption{{\bf Top:} Two models from Figure \ref{fig:fallback} showing temporal gaps in the fall-back rate, but now calculated using a realistic spread in the $r$-process heating experienced by different fluid elements due to variations in their $Y_e$ values (eq.~\ref{eq:Qtot}) (see also Fig.~\ref{fig:heating_rate}, bottom panel). The mean values for $Q_{\rm tot}$, around which the spread is centered, are shown in the figure. The previous model with a large temporal gap in the fall-back rate ($t_{\rm heat} = 1.75$ s; {\it blue}) now shows a complete cut-off, while the case with a shorter gap ($t_{\rm heat} = 1.5$ s; {\it red}) has been smoothed out to a lull in accretion.  {\bf Bottom:} Mass fall-back evolution calculated using $r$-process heating curves taken directly from the output of SkyNet simulations (Fig.~\ref{fig:heating_rate}) mapped into our NS-BH simulation data based on their $Y_e$ values.  We see a gap behavior because the ejecta properties lie close to the critical line $\eta = \eta_{\rm c}$ line for the $M = 6M_{\odot}$ black hole (red solid line in Fig.~\ref{fig:param}), but again the gap is partially filled-in due to the spread in heating properties.}
  \label{fig:Yespread}
  \end{center}
\end{figure}

Our calculations shown in Fig.~\ref{fig:fallback} were performed under the assumption that all fluid elements experienced heating characterized by single values of $Q_{\rm tot}$ and $t_{\rm heat}$.  While reasonable as a first-order approximation (Fig.~\ref{fig:heating_rate}), in detail these parameters will vary between fluid elements as a result of a finite spread in their initial electron fraction $Y_{e}$ and precise thermodynamic conditions (e.g. entropy and expansion rate, which affect the properties of the seed nuclei).  It is thus important to address whether the different fall-back outcomes discussed above, particularly the presence of long temporal gaps in accretion, are preserved in the face of such realistic heating variations.

In order to explore the impact of a physical heating spread on our results, we vary the value of $Q_{\rm tot}$ between fluid elements based on their $Y_e$ value (as taken from the simulation data) using equation (\ref{eq:Qtot}; see also Fig.~\ref{fig:heating_rate}, bottom panel).  The other free parameters in the equation (e.g.~$\bar{A}/\bar{Z}$) are chosen to match the {\it mean} values of $Q_{\rm tot}$ and $t_{\rm heat}$ to the comparison cases in which these values are fixed for all fluid elements (e.g., as in the cases shown in Fig.~\ref{fig:fallback})

Figure~\ref{fig:Yespread} shows the effect of $Y_e$-dependent heating on $\dot{M}(t_{\rm fb})$ compared to the two previous models from Figure \ref{fig:fallback} which showed gaps in the fall-back rate.  The case with an initially long gap of $\gtrsim 30$ s was transformed into a complete cut-off by the heating spread.  However, in the case with a shorter gap of $\sim 20$ s the effect of the finite heating spread is to smooth out, but not eliminate, the gap in mass fall-back, in other words turning the "gap" into a "lull".  Our initial conclusion that $r$-process heating can lead to at least partial gaps in the fall-back when the critical condition $\eta \approx \eta_{\rm c}$ is satisfied (where now $\eta$ is defined using the mass averaged values of $Q_{\rm tot}$ and $t_{\rm heat}$) thus appears to be robust.

Our calculations thus far have employed a step-function heating profile as given by eq.~\ref{eq:qdot}.  To explore the sensitivity of our conclusions to this assumption, we perform an identical calculation where we directly using the direct heating curves from SkyNet (Fig.~\ref{fig:heating_rate}, top panel), which have been mapped onto the ejecta from our simulation data according to their closest $Y_e$ value (e.g.~\ref{fig:ye_u}).  We still assume that heating for a given fluid element goes to zero when re-compressing ($v_r < 0$).  The results of this simulation, as shown in the bottom panel of Fig~\ref{fig:Yespread}, is fall-back with a gap of about 10 seconds.  This is because the heating parameters for our fiducial simulation of a NS merging with a $\approx 6M_{\odot}$ BH overlaps with the gap condition $\eta \approx \eta_{\rm c}$ (red solid line in Fig.~\ref{fig:param}).

\hfill \break
\section{Implications for Extended Emission in SGRBs}
\label{sec:discussion}

\begin{figure}
  \begin{center}
  \includegraphics[width=0.48\textwidth]{YeM}
  \caption{The critical condition $\eta = \eta_{\rm c}$ (eq.~\ref{eq:eta}) in the space of BH mass $M$ and ejecta electron fraction $Y_e$, which separates a temporal gap, versus a cut-off, in the rate of fall-back accretion. The value of $\eta$ is calculated by mapping $Q_{\rm tot}$ to $Y_e$ using equation \ref{eq:Qtot} for different values of $t_{\rm heat}$ as extracted from the results of our SkyNet calculations for the nuclear heating rate. As long as the ejecta is sufficiently neutron-rich ($Y_{e} \lesssim 0.2$), the low-mass black hole remnants of NS-NS mergers are predicted to experience a cut-off in the fall-back rate, while the more massive BHs from NS-BH mergers should experience a gap or lull in fall-back, consistent with the extended emission observed after a fraction of SGRBs (Fig.~\ref{fig:lc_grbee}).}
  \label{fig:YeM}
  \end{center}
\end{figure}

As described in $\S$\ref{sec:results}, the condition $\eta = \eta_{\rm c} \approx 0.95$ separates two distinct regions in the space of $Q_{\rm tot}-t_{\rm heat}$ shown in Fig.~\ref{fig:param}: the lower left corner  ($\eta \ll \eta_{\rm c}$), where fall-back has a gap or is uninterrupted, and the upper right ($\eta \gg \eta_{\rm c}$), where fall-back exhibits a complete cutoff.

The heating properties of the ejecta from our NS-BH simulation, which left a black hole of mass $M \simeq 6M_{\odot}$, lies in the gap region close to the solid red line.  We have confirmed this behavior by calculating the fall-back rate directly using SkyNet heating trajectories (Fig.~\ref{fig:Yespread}, bottom panel).  However, because $\eta \propto M^{-2/5}$ (eq.~\ref{eq:eta}), otherwise similar ejecta from a merger that resulted in central black hole of lower or greater mass would instead result in $\eta \gg \eta_{\rm c}$ or $\eta \ll \eta_{\rm c}$, respectively, and thus would exhibit qualitatively different fall-back behavior.   Figure \ref{fig:YeM} shows the condition $\eta = \eta_{\rm c}$, now in the space of black hole mass $M$ and electron fraction $Y_e$, where we have used the relationship $Q_{\rm tot}(Y_e)$ from eq.~(\ref{eq:Qtot}) (see bottom panel of  Fig.~\ref{fig:heating_rate}).

If the X-ray luminosity of the extended prompt emission following a short GRB is proportional to the mass fall-back rate, $L_X \propto \dot{M}$, then this reasoning would suggest that NS-NS mergers ($M \approx 2.5M_{\odot}$) with similar ejecta properties would lie in the regime $\eta \gg \eta_{\rm c}$ and thus should generate little or no late-time fall-back and hence would not be accompanied by luminous extended X-ray emission. By contrast, NS-BH mergers, given their more massive BHs $\gtrsim 5M_{\odot}$, lie in the regime $\eta \sim \eta_{\rm c}$ or $\eta \lesssim \eta_{\rm c}$ and thus could produce fall-back with temporal gaps extending up to tens of seconds, in agreement with those short GRBs showing extended emission (Fig.~\ref{fig:lc_grbee}).

One caveat is that, while these conclusions hold for highly neutron-rich ejecta ($Y_e \lesssim 0.2$), as characterizes the equatorial tidal tails in NS-NS and NS-BH mergers, it would not necessarily apply to the most polar-concentrated shock-heated dynamical ejecta, which experiences stronger weak interactions.  At least in the case of NS-NS mergers, this has been shown to give rise to a wider range of $Y_e$ \citep{Wanajo+14,Goriely+15,Sekiguchi+16}, potentially extending to values $Y_e \gtrsim 0.2$ that would place even NS-NS mergers into the $\eta \sim \eta_{\rm c}$ regime and result in some fall-back.  However, because in many cases the quantity of high $Y_e$ matter is likely to be much less than the total, the amount of fall-back from this component would be significantly smaller and the presence of a cut-off in the fall-back rate might be preserved.

Our results suggest the possibility that the two apparent classes of SGRBs$-$those with and those without extended emission$-$may be associated with NS-BH and NS-NS mergers, respectively.  Such a dichotomy of origin was previously suggested on the completely different basis of the observed distribution of spatial offsets of short GRBs from their host galaxies \citep{Troja+08}; however, the statistical significance of this difference was subsequently challenged \citep{Fong&Berger13}.

Is such a model consistent with current event rate constraints? A fraction $f_{\rm EE} \gtrsim 0.2-0.4$ of SGRBs are accompanied by extended emission (\citealt{Norris&Bonnell06}). For our progenitor dichotomy scenario to hold, the ratio of the volumetric rate of NS-BH mergers to that NS-NS mergers must be at least as high as $f_{\rm EE}/f_{\rm SGRB}$, where we have assumed that all NS-NS mergers are accompanied by a SGRB but only a fraction $f_{\rm SGRB} < 1$ of NS-BH mergers do the same (as the latter requires rapid BH spin in the prograde direction relative to the orbit for the NS to be tidally disrupted outside the BH horizon).

From the first and second observing runs of Advanced LIGO, the observed rate of NS-NS mergers is $\mathcal{R}_{\rm NSNS} = 110-3840$ Gpc$^{-3}$ yr$^{-1}$ at 90\% confidence, while the upper limit on the rate of mergers of $\gtrsim 5M_{\odot}$ with NSs is $\mathcal{R}_{\rm NSBH} \lesssim$ 610\,Gpc$^{-3}$ yr$^{-1}$ \citep{LIGO+18CATALOG}. The ratio of these rates is thus only weakly constrained at present, such that as long as a moderate fraction of NS-BH mergers produce GRBs,
\begin{equation}
f_{\rm SGRB} \gtrsim f_{\rm EE}\left(\frac{\mathcal{R}_{\rm NSNS}}{\mathcal{R}_{\rm NSBH}}\right) \gtrsim 0.05\left(\frac{f_{\rm EE}}{0.3}\right),
\end{equation}
one cannot yet rule out the possibility that NS-BH mergers are sufficiently common to account for the population of SGRBs with extended emission ($f_{\rm EE} \gtrsim 0.2-0.4$).  While thus far one NS-NS merger has been discovered compared to zero NS-BH mergers, the statistics of the current sample are obviously very small.  If all extended emission is attributed to fall-back accretion in NS-BH mergers, then our model implies that the steady-state discovery rate of of NS-BH mergers will be significantly higher than that of NS-NS mergers (and that a sizable fraction of the BHs in these systems are spinning in the prograde orbital direction).

\section{Conclusions}

Despite the recent discovery of a short burst of gamma-rays in association with the gravitational waves from a NS-NS merger, the origin of the temporally-extended X-ray emission which is observed following a significant fraction of short GRBs remains a mystery.  Late-time activity from the black hole accretion disk powered by fall-back of marginally bound debris, as would naively be expected in both NS-NS and NS-BH mergers, has been proposed as a source of this behavior (e.g.~\citealt{Rosswog07}).  Following \citet{Metzger+10a}, we have employed a simple model to explore the impact of $\beta-$decay heating due to $r$-process nucleosynthesis on the time-dependence of the mass fall-back rate, using initial data on the ejecta fluid elements (Fig.~\ref{fig:ye_u}), and the properties of the $r$-process heating received (Fig.~\ref{fig:heating_rate}), extracted directly from NS-BH merger simulations.

We confirm that this $r$-process heating significantly alters the fall-back rate from the canonical $\dot{M} \propto t^{-5/3}$ behavior, generating instead either an abrupt cut-off, or temporal gap, in the fall-back rate on a timescale of $\sim 10-100$ s (Fig.~\ref{fig:fallback}, \ref{fig:param}).  This behavior is robust to the presence of a realistic spread in the heating properties of the fluid elements imparted by a realistic range in the electron fraction and thermodynamic history (Fig.~\ref{fig:Yespread}). Whether a cut-off or gap behavior is obtained depends on the value of a critical dimensionless parameter $\eta$ (eq.~\ref{eq:eta}). The dependence of $\eta$ on black hole mass suggests a possible distinction between cut-off behavior in NS-NS mergers (low black hole mass) and delayed fall-back in NS-BH mergers (high black hole mass), as illustrated in Fig.~\ref{fig:YeM}. The presence or absence, respectively, of extended emission thus provides a possible way to distinguish NS-BH from NS-NS mergers.

Our model could be improved or extended along several fronts in future work. In addition to the BH mass, the critical parameter $\eta$ depends on the total energy $Q_{\rm tot}$ and heating timescale $t_{\rm heat}$ of the $r$-process.  These properties are related to the $Q$ values and $\beta-$decay rates of neutron-rich isotopes whose masses and other properties have yet to be measured by laboratory experiments (e.g.~\citealt{Horowitz+18} and references therein).  A more thorough parameter study of the range of $t_{\rm heat}$ and $Q_{\rm tot}$, e.g. assuming different theoretical models for the nuclear masses, would provide an additional check on the robustness of our conclusions.

More ambitiously, multidimensional hydrodynamical simulations of the fall-back process, accounting for the effects of $r$-process heating, are needed for a more robust assessment of the gap or cut-off formation process.  Our treatment of directly placing the $r$-process thermal energy into debris kinetic energy neglects the transfer of thermal energy between adjacent fluid elements, though the highly-supersonic and nearly radial motion of the debris should mitigate these effects (Fig.~\ref{fig:schematic}).  Models that do not self-consistently include the back-reaction of the thermodynamics of the fluid elements on the $r$-process path (\citealt{Rosswog+14}) may be inadequate, because once matter starts to recompress and adiabatically heat, the rate of $\beta-$decay heating will be substantially suppressed as the $r$-process path moves back towards the stable valley due to the higher temperatures \citep{Metzger+10a}.  This complex "feed-back"  process may ultimately necessitate coupling at least a simplified $r$-process network (e.g., a one-zone model such as that of \citealt{Lattimer+77}) directly into the hydrodynamical simulations.

\section*{Acknowledgements}

We thank Daniel Kasen for early help on this project.  D.~D.~acknowledges support from the UC Berkeley Summer Undergraduate Research Fellowship. B.~D.~M.~is supported by NASA (grant NNX16AB30G).  We thank Jonas Lippuner and Luke Roberts for providing the SkyNet heating data used in our analysis.  F.~F.~gratefully acknowledges support from NASA through grant 80NSSC18K0565, and from the NSF through grant PHY-1806278.

redpajama_set_name: RedPajamaArXiv


text:
La maison Maraite est une maison classée située dans le village de Bellevaux faisant partie de la ville de Malmedy en Belgique (province de Liège).

Localisation
Cette maison est située au 11 du village ardennais de Bellevaux, à environ  à l'ouest de l'église de la localité.

Historique
La maison est construite en 1592 comme l'indique l'inscription gravée sur le linteau de l'entrée : ANO. DNI 1592.

Description
La maison Maraite est constituée, à gauche, d'un corps de logis de deux niveaux et demi et, à droite, d'étables et grange sur un niveau et demi. La construction est réalisée en colombages et torchis chaulé (pour le corps de logis) ou briques peintes (pour les étables) avec ossature en pans-de-bois. Le corps de logis se compose de quatre pièces disposées en carré par niveau. La porte d'entrée se trouve sur la travée de droite du corps de logis. La façade du corps de logis présente entre le rez-de-chaussée et le premier étage un léger encorbellement soutenu par seize poutres dont six reposent sur des consoles obliques en bois.

Notes et références

Voir aussi

Articles connexes
 Liste du patrimoine immobilier classé de Malmedy
 Maison Briska
 Maison Villers
 Maison Cavens

Patrimoine du XVIe siècle
Patrimoine classé à Malmedy
Maraite
Maison à colombages

redpajama_set_name: RedPajamaWikipedia


text:
Wings Field Preservation Associates, L.P. v. Commonwealth of Pennsylvania, Department of Transportation
Summary judgment granted in favor of plaintiff airport owner in matter concerning constitutionality of County Code section that delegated to municipality authority over airport funding; section declared "special legislation" and found to be unconstitutional because it vested in one county a power that could not be exercised by the other counties in the same class and because DOT failed to articulate any rational basis for the classification.
Argued: March 8, 2000
Wings Field Preservation Associates, L.P., (Wings Field) has filed a motion for partial summary judgment (Wings Field Motion) in connection with the petition for review in the nature of a complaint for declaratory judgment (Petition) previously filed by Wings Field in this Court's original jurisdiction. The Commonwealth of Pennsylvania, Department of Transportation (DOT), also has filed a motion for summary judgment (DOT's Motion) with respect to the Wings Field Petition. Both motions are presently before this Court for disposition. *fn2 We grant summary judgment in favor of Wings Field.
The following material facts are undisputed. Wings Field is the owner of Wings Field Airport (Airport), a seventy-year-old privately owned, public use airport located in Whitpain Township (Township), Montgomery County. In June 1999, Wings Field submitted a pre-application to DOT seeking a grant to pay for a runway project at the Airport. DOT would not consider the request because Wings Field lacked the township and county approvals required by Section 2210 of the County Code. *fn3 On July 29, 1999, the Township voted not to approve the project, and, because of the Township's action, Montgomery County decided not to consider the project. *fn4
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270 DEGREE VIEWS FROM THIS MOUNTAIN TOP HOME IN ATENAS, COSTA RICA.
This beautiful, well built pool home is located in Vista Atenas, the first expat community developed in Atenas, Costa Rica. Perfectly situated at 1000 meters (3300 feet) above sea level, this home has incredible and quite unique views of more than 270 degrees of the Central Valley and the surrounding sierras, including volcanos Irazu, Turialba, Barva and Poas to the east and north-east, the sierra of Busta Mante to the south, the Pacific Ocean and the peninsula of Nicoya to the west and north-west. The Pacific beaches are less than one hour drive away via Highway 27 or Highway 3. This private residence is at the end of a 1.7 Km (more than one mile) street, in a very quiet residential area of high end homes with no thru traffic.
Carefully built in 2006 on an anti-seismic foundation, this home offers 250 m2 (2,700 s.f.) of construction under roof. Some of the many features of the home include: spacious open living areas, a large master suite with ample walk-in closet, en-suite bath, complete with walk-in shower and bidet, two guest bedrooms, with a shared bathroom, fully equipped custom kitchen with all the amenities, laundry room and carport. There is a wrap around porch that is ideal for taking in all the views from this beautiful home. The hot water is provided by a solar system with electric backup (rarely used). The independently solar heated swimming pool has a direct access from the master bedroom as well as the common wrap around terrace.
The house sits on 6375 m2 (about 1.575 acre) land with a smaller building site, ideal for a guest house. There are many tropical plantings on the property and a wide variety of fruit trees. This wonderful property is being offered for sale at only$425,000.00.


Proposed build from Affinity Homes LLC showcases modern Farmhouse design with every amenity for comfortable luxury living in Southwest Washington's premiere gated, golf course development, The Parklands at Camas Meadows. Photos presented are of a home built in collaboration with Generation Homes NW LLC.
The brilliant single-level design maximizes space while emphasizing distinct living areas. Created with entertaining in mind, the home offers three bedrooms, 3.5 bathrooms, a guest house, and multiple living spaces designed around a central courtyard entrance.
The open-concept layout has been specifically designed to bring tranquil bright undertones into the home and create a welcoming space year-round.
The gourmet kitchen features a large walk-in pantry, high-end stainless steel appliances, and a huge island workspace that overlooks the open-plan dining and lounge room with beautiful gas fireplace.
Just off the open space, marvel at two sets of retracting glass wall systems that create a seamless connection with the outdoor living space. Completely private, the large covered patio offers the ideal space to dine alfresco, relax with friends or spend quality time as a family.
For added privacy and functionality, the sleeping quarters are in a separate wing of the home. Two bedrooms have walk-in closets and easy access to the shared bath with twin vanities.
The master suite was created to bring to mind a luxury retreat. Get away from it all right at home in this beautiful suite designed to offer complete relaxation and tranquility. Enjoy a grand dressing room, a beautifully-appointed ensuite with twin vanities, and a luxurious over-sized shower.
When hosting overnight guests, thrill them with the "casita" or guest house. It has a private entrance off the courtyard, as well as a hidden entrance to the main house. Flexible live-work space, full bath, and wet bar make this space highly functional and effortlessly comfortable for a single overnight or a longer-term guest. A great hideaway for guests, mothers-in-law, or teenagers seeking a bit more privacy while staying connected.
A powder room, three-car garage with mud room and separate laundry room complete the floorplan of this exceptional single-level family home.
Care and attention to detail has also gone into the placement of this home to make the most of the large greenbelt lot. The owners of this property can enjoy maximum privacy, plus a lovely backdrop that emphasizes the beauty and serenity of this part of the world.
I found this listing at 3428 NW Mcmaster Dr in Camas and would like more information. Thank you.


Read this brief historical account of the Aurora Fire Department.
Learn about Aurora's first hand pumped fire engine, and also the history of the 1850s era Button Fire Engine on exhibit in the Aurora Regional Fire Museum.
Read about the tragic Woolworth Fire of 1934, where three Aurora firefighters died in the line of duty when a building collapsed.
Informtion on the more than 600 paid firefighters who have protected the citizens of Aurora.
150th Anniversary with firefighting demonstrations, a fire apparatus parade, memorial services, firefighters reunion, and numerous other activities throughout the year.
Learn about the Aurora Fire Department Today, and find links to the AFD's official website.


A raisin is a dried grape. Raisins are produced in many regions of the world and may be eaten raw or used in cooking, baking and brewing.
Raisins, like all dried fruits, are very good tools for gaining weight in a healthy way, since they are full of fructose and glucose and contain a lot of potential energy. Raisins contain small amounts of several B vitamins. B vitamins convert food into fuel to give you energy. They also keep your nervous system in working order and help you maintain a healthy liver, skin, hair and eyes.
Raisins that are fresh and have been stored properly will require no special attention prior to eating or using in a recipe. Raisins are a great addition to homemade granola or can be sprinkled over any breakfast cereal, hot or cold. Raisins' sweetness and texture make them a great addition to every dish. These are convenient, high energy low fat snack; they are easy to pack, easy to eat and almost never go bad.
-The natural sugars of raisins are a great source of energy and come packaged together with fiber and other nutrients.
-Since raisins are high in potassium and low in sodium this makes them an ideal part of a heart healthy diet.
-The fiber in raisins, combined with other food from plants high in fiber, helps to regulate intestinal function and proper elimination.
-Raisins like grapes are one of the few fruits that contain a reasonable level of tartaric acid that works together with fiber to help proper elimination and help keep the colon healthy.


Showcasing a beautiful golf course or resort property via video can be exciting and sometimes more appealing than words in an article. The following are some of our videos we hope you'll enjoy watching on YouTube. Please feel free to share with family and friends. Thank you.
To watch a video from a particular area of the USA or the World, click on the location below.
...a pride of Alabama's Gulf Shores and Gulf Coast!
One of Ray Floyd's Best In Southwest Florida…waste bunkers and lots of water!
..Exciting Growth and New Renovations as MetLife Takes Ownership.
Sarasota, Florida Rich in Golfing and Vacation Choices Enjoy Beach, Cultural, Family Activities & Great Cuisine.
Enjoying History, Golf and Fun Together at Wintergreen Resort, Monticello, Colonial Williamsburg, Kingsmill Resort, Jamestown Settlement & Busch Gardens.
...As Good As the Lobster!
Playing one of the best in the area with outstanding views.


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LG's upcoming flagship Android Phone, the G6 has not been a secret for long, some leaks have surfaced in past that cover several interesting things about the phone, but we have not seen complete photos of the G6.
9to5Google found some leaked pictures of LG G6, and from the images, it looks like the phone will feature a dual rear camera setup, a metal design and an always on display.
The specs of the phone have been revealed too. The G6 will sport a 5.7-inch display, 32 GB of internal storage and a 3,200 mAh battery to power its Qualcomm Snapdragon 821 System-on-chip paired with 4 GB of RAM. The display will have QHD resolution, and unlike most other smartphones in the market, the phone will have a 2:1 screen aspect ratio.
Apart from the above specs, LG has already said that the phone will come with a 32-bt Qual-Dac just like the LG V20 did last year, and the phone will run a newer version of its LG UX software with a version number 6.0.
The phone should be launched in an event at MWC 2017 on February 26, there is no information about its pricing, but it should be known soon too. What do you think about the phone? Share with us in the comments below.


text:
Business School News
How Washington University Built An Entrepreneurial Powerhouse
by: Nathan Allen on October 29, 2019 | 0 Comments Comments 7,651 Views
The T-Rex coworking space in St. Louis. Courtesy photo
Silicon Valley has Stanford University. Cambridge boasts MIT and Stanford. Austin has UT-Texas. In the center of every thriving entrepreneurial ecosystem sits a university. And that's exactly the model that has found itself in what many might consider an unlikely place for a new business Renaissance: St. Louis and Washington University.
For proof, look no further than a former furniture factory not far from the banks of the Mississippi River, where colorful desks and chairs are scattered across a spacious — and renovated — industrial coworking space. Exposed bricks and pipes that used to resemble blue-collar work now serve as a hipster enclave for 20- and 30-somethings jumping from one Apple screen to another.
"The entrepreneurs have really been the anchor for the revitalization of downtown," Cliff Holekamp says as he walks through T-Rex, the coworking space on Washington Avenue in downtown St. Louis. "That's the big role at T-Rex," adds Holekamp, a serial entrepreneur and angel investor who created a robust entrepreneurship curriculum at Washington University's Olin School of Business. "It's to incubate these companies. And as they grow out of the space, they find spots nearby in the local community."
St. Louis — like many Midwestern American cities — rests on generations of innovation. By 1764, French fur traders began populating the area. Once the Osage Nation was pushed out to reservations in Oklahoma or elsewhere, the land underneath St. Louis officially became part of the U.S. in 1803 with the Louisiana Purchase. It was officially incorporated as an American city when Missouri became a state in 1821.
Even before then, it quickly became one of the country's largest cities and most important inland hubs sitting on the confluence of the Missouri and Mississippi Rivers as riverboats began arriving in 1818. Like many Midwestern towns, St. Louis's population and industry peaked in the 1950s. Since then, people have fled to the suburbs, leaving empty buildings and lots in their wake. Until now.
THE REGROWTH OF A CITY
Over the past decade, gastropubs full of 20-somethings have popped up across the street from abandoned lots. Apartment and condo complexes are being renovated and constructed. Instead of knocking over buildings and starting over, many new startup hubs like T-Rex — and the nearby Cortex district — have flipped buildings, taking over old rotary phone and furniture factories and placing coworking and office space that rivals anything you'd see in the San Francisco Bay Area or New York City.
Statistically, Holekamp says, the residential occupancy downtown is at 97% but the commercial occupancy is under 70%. "It's become a hugely popular place to live but they're struggling to fill up their commercial occupancy," Holekamp says. "So what we're trying to do is create the next generation of occupants — both residential and commercial."
Since 2010, St. Louis's downtown population has surged by 43.5%. Going back to 2005, the rate climbs to 153.5%. Between its graduates and current tenants, T-Rex claims it has created more than 4,300 jobs with a combined economic output of more than $607 million. "That's the goal of T-Rex, to incubate these companies and as they grow out of this space, they go into the nearby community," Holekamp says. "And a large percentage do stay downtown because they got their roots here. And then they hire young people because young people want to be down here. They don't want to work out in Chesterfield."
THE BIRTH OF AN ENTREPRENEURSHIP PROGRAM
Holekamp would certainly know. He's been deeply embedded in the entrepreneurial landscape in St. Louis for more than a decade. And he's nearly single-handedly architected the entrepreneurship program at Washington University's Olin Business School, which ranked first in our debut ranking of MBA programs in entrepreneurship.
After graduating with his own MBA from Olin, Holekamp created a chain of podiatry centers around the St. Louis region called Foot Healers. "I found myself with a little free-time and thinking about what I was going to do next," Holekamp says about selling the chain in 2007. So he reached out to the Olin School, which happened to have an opening for an adjunct professor to teach their only two entrepreneurship courses — Introduction to Entrepreneurship and The Hatchery — starting in the spring of 2008.
Olin's entrepreneurial roots began in 1999 when the school launched programming for what would become the Skandalaris Center for Interdisciplinary Innovation and Entrepreneurship. In 2001, the Center's namesake, Bob and Julie Skandalaris donated a large fund. And by 2003, thanks to another large grant from the Kauffman Foundation, the Skandalaris Center had the funding necessary to start making a real impact at Washington University. Holekamp calls it the "first real decision" by the school to "truly invest in entrepreneurship." And the Center's current managing director, II (pronounced "two") Luscri, calls in the "foundation that everything has been built on to today."
A 'FREE-TRADE' BETWEEN GRADUATE PROGRAMS
Despite the clunky name, the center has set the tone for entrepreneurship education at Washington University. A few years after the launch its launch, the Center was officially moved outside of the business school and into what Luscri, who also holds the title of assistant vice provost for innovation and entrepreneurship at WashU, calls an "academically neutral" space.
"They didn't want to send a message that this was just for business students," Holekamp explains. "They wanted it to be interdisciplinary, cross-campus because collaboration is a fundamental part of entrepreneurship."
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Tagged: Cliff Holekamp, Cortex, entrepreneurship, Hank Webber, Mark Taylor, Olin Business School, Skandalaris Center of Interdisciplinary Innovation and Entrepreneurship, T-Rex, Washington University in St. Louis, WashU
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Needless to say, I felt disappointed. Not only because I had hoped for some magic formula to make money but also because I felt that coming from the greatest investor the world has ever seen, this was too obvious a thing to say. Now I realise how wrong I was. The true meaning behind those simple looking words wasn't as obvious as I had thought.
The conventional wisdom in investing is that you just need to stay invested for a really long time in order to earn above average returns. While generally true, there are exceptions to this rule; exceptions which can be very costly.
The chart compares the holding period return of equity vs. bank fixed deposits. Notice the years marked with a red arrow – 1992 and 2008. Had you invested a lump sum amount in those 2 years and held on till 2015, you would have earned a measly 8.50% and 8.65% respectively. Yes, that's right. You would have done better had you invested in a fixed deposit.
(That is not to say that you should be invested in fixed deposits instead of equity. Check this for a better perspective on why you should think beyond fixed deposits).
Let's concentrate on 1992 for a moment. Even after 23 years, an investor would have underperformed FDs. That's a bit of a jolt to say the least. And here is an interesting fact. Had the investment been delayed for just a year and made in 1993, the investor would have ended up with a 12% CAGR, easily outpacing FDs and inflation.
So what is happening here? The huge difference in return is due to what happened in the year 1992. Markets fell almost 47% and the investment ended up trying to play catch up for the remaining 22-year period.
Same was the case with the year 2008 when markets fell 38%.
Now, as I mentioned earlier, these are exceptions, and that generally, equities would outperform fixed income. There is no denying that. But you cannot predict when you may fall victim to that exception.
It is pertinent to note that when investing in the equity markets, wrong entry points can prove costly. One should try and avoid big negatives, because you may end up working your entire life trying to recoup those losses.
What can an investor do to avoid such scenarios?
As you can see, regular investments earned FD-beating returns in both those years – 12.30% and 13.60% respectively. They also easily beat lump sum investments in those years. Although regular investing lagged in a few of the other years, it always earned more than an FD.
Given this analysis, the lessons become obvious.
Rather, invest regularly (monthly, quarterly, etc.). Systematic investments may not give you the high returns of a lump sum investments made at the right time, but they also ensure that your entire capital is not invested at the very top of a market. In the past at least, systematic investments have given FD-beating returns.
If you keep the above tenets in mind, navigating the complex world of equity investing should become easier. Remember that despite their fluctuations, equity markets remain a great avenue for building long term wealth.
Dividends have been ignored in the above calculations for the sake of simplicity.
Historical fixed deposit rates: Reserve Bank of India – Handbook of Statistics on Indian Economy 2013-14. Note that fixed deposit rates for the years 2011-12 to 2014-15 have been assumed.
Historical Sensex levels/ returns: Bombay Stock Exchange website.