text:
\section{Introduction}\label{sect:introdctn}
It is well known that the MACHO experiment towards the Large Magellanic Cloud
(LMC) yielded invaluable contributions to variable star research. The discovery
of five distinct period-luminosity (PL) relations of lower mass RGB and AGB
giants
\citep[e.g.][]{wood99} is probably the best known example. Another legacy of
the experiment, was the discovery of 33 Pop II Cepheids and RV Tauri stars in
the LMC \citep{alcock98} and the definition of a single PL relation of both
groups with the appearance of the RV\,Tauri characteristic lightcurves
(alternating deep and shallow minima) at the high luminosity end: the RV\,Tauri
stars are a direct extension of Pop II Cepheids to longer periods. Absolute
luminosities were derived and the RV\,Tauri stars were confirmed to be likely
post-AGB stars, making these objects members of the small group  of post-AGB
stars with known luminosities. For Galactic RV\,Tauri stars there is no direct
probe to the luminosity but they were identified as post-AGB stars by
\citet{jura86}, mainly on the basis of the presence of an IR excess due to
circumstellar dust around many of them.

The post-AGB phase is a short phase, so not many of these sources are known
\citep[see][for a catalogue of candidate post-AGB objects]{stasinska06}.
Their temperature-gravity domain makes it possible to study a very wide range
in chemical species by their atomic transitions (if optically bright enough).
They are therefore ideal objects to constrain the AGB nucleosynthetic and
evolutionary models. Interestingly, post-AGB stars are chemically much more
diverse than theoretically anticipated: only a very small group of objects
shows direct chemical evidence for AGB nucleosynthesis, being enhanced in
carbon and enhanced in neutron capture s-process elements
\citep[e.g. review by][and references therein]{vanwinckel03}. Since the
post-AGB evolutionary tracks pass the Cepheid instability strip, the pulsating
RV\,Tauri stars could be, in principle, good candidates to test further AGB
chemical evolutionary models.

In recent years it became, however, clear that also for RV Tauri stars the
chemical picture is complex and {\em chemical} evidence for a post-AGB nature
(possible C-enrichement and s-process overabundances) is {\em not} found in
Galactic RV\,Tauri stars \citep[except for maybe V453\,Oph, for which a mild
s-process overabundance was found, see][]{deroo05}. In RV\,Tauri stars,
depletion abundance patterns prevail \citep{giridhar05,maas05}. The basic
scenario of the badly understood depletion process involves a chemical
fractionation due to dust formation in the circumstellar environment followed
by a decoupling of the gas and the dust with a reaccretion of the cleaned gas
on the stellar photosphere, which leaves it depleted of the refractory
elements. \citet{waters92} showed that the most favourable circumstance for
this process to occur is, if the circumstellar dust is trapped in a disc. The
presence of a disc in evolved objects is likely to be related to binarity
\citep[e.g.][]{vanwinckel03} which means that binarity must be widespread in
RV\,Tauri stars \citep[see also][]{deruyter06}.

The LMC sample of RV\,Tauri stars with their known luminosity is a unique
sample to study the nature of these stars and of the post-AGB evolution in
general. Moreover, abundance analyses of post-3rd dredge-up stars in the LMC
should make it possible to study the yields of the AGB nucleosynthesis in a
more metal deficient environment than the Galaxy. With the advent of
high-resolution spectrographs on 8\,m class telescopes, it is now feasible to
study in detail the abundance patterns of these individual RV Tauri candidates
in the LMC. The brightest object of the
\citet{alcock98} sample, MACHO$^{*}$04:55:43.2-67:51:10, also named as
MACHO\,47.2496.8, was studied at low resolution by \citet{pollard00}
and by \citet{lloydevans04}.
The basic parameters of MACHO\,47.2496.8 are summarised in
Table~\ref{tab:smbdgegevens}. Contrary to what is found in Galactic RV\,Tauri
stars, this object shows clear indications of a strong C-enhancement and of
s-process overabundances. The low-resolution spectra at different photometric
phases of MACHO\,47.2496.8 show that it is  strongly carbon enriched
(C/O\,$>$\,1) with strong C$_2$ bands at deep minima. Spectra taken at a
resolution of 0.12\,nm with the 1.9m SAAO telescope around deep minimum (phase
0.88) and with the Anglo-Australian Telescope near maximum light (phase 0.61)
show that the C$_2$ bands disappear almost completely at maximum light, with
only the actual bandhead of the origin band at 5165\,\AA\ still readily
detectable. The spectrum at minimum showed strong bandheads of $^{12}$C$^{12}$C
at 4737 and 4715\,\AA\ but the 4744\,\AA\ bandhead of $^{12}$C$^{13}$C was very
weak or absent, indicative of a high $^{12}$C/$^{13}$C ratio. Enhancements of
the Ba\,{\sc ii} spectral features at 4554\,\AA\ and 4934\,\AA\ were detected
on these spectra, making this object a very interesting star to study the AGB
nucleosynthesis in the LMC in detail.

In this paper, we will present a detailed
abundance analysis based on high-resolution, high signal-to-noise VLT-UVES
spectra. The paper is organised as follows: in Sect.~\ref{sect:photomtr} we
summarise the available photometry of the object, and discuss its variability
and extinction. In Sect.~\ref{sect:uvesbsrvtns}, the high-resolution
observations are briefly discussed, while Sect.~\ref{sect:abundancenlss} is
devoted to the actual analysis and the abundance results. In
Sect.~\ref{sect:discussionntrxtr} we discuss the abundance pattern, and
address the question whether the star is intrinsically or extrinsically
enriched in s-process elements. We end with the main conclusions
(Sect.~\ref{sect:maincnclsns}).

\begin{table}\caption{Basic parameters of MACHO\,47.2496.8.}\label{tab:smbdgegevens}
\begin{center}
\begin{tabular}{rrr}
\hline\hline
\multicolumn{3}{c}{\rule[-0mm]{0mm}{4mm}\bf\large MACHO\,47.2496.8}\\[.4mm]
\hline
Coordinates   & $\alpha_{2000}$ &     4 55 43.23 \\
              & $\delta_{2000}$ & $-$67 51 10.4 \\
\hline
Mean magnitude   &   V &14.97 \\
\hline
Spectral type &  & Supergiant\\
              &  & pulsating between\\
              &  & early K and late F\\
\hline
\end{tabular}
\end{center}
{\small Source coordinates: MACHO; magnitude: \citet{alcock98}; spectral type:
\citet{pollard00}.}
\end{table}

\section{Variability, extinction and luminosity}\label{sect:photomtr}
\subsection{MACHO photometry}
The database of the MACHO project \citep{alcock92, alcock95}, accessible via
{\tt http://wwwmacho.anu.edu.au/}, contains 260 simultaneous measurements of
MACHO\,47.2496.8 in the blue MACHO filter V$_{\rm M}$ and red MACHO filter
R$_{\rm M}$, and 465 additional measurements in V$_{\rm M}$ only. We performed
a frequency analysis on the 725 V$_{\rm M}$ magnitudes, using the
Jurkevich-Stellingwerf phase dispersion minimization ({\sc pdm})
method \citep{stellingwerf78}, and deduced a ``formal'' period (the period
between two successive deep minima) of P\,$=$\,112.97\,d ($\theta$-statistic
of $\theta$\,$=$\,0.23), which is slightly longer than the period in
\citet{alcock98}, being P\,$=$\,112.45\,d. Two outliers were removed from
the frequency analysis. A part of the V$_{\rm M}$ light curve for
MACHO\,47.2496.8 is also shown in Fig.~1 of \citet{pollard00}. Our period of
112.97 days and the epoch of minimum light, JD2448673.384, are used as the
basis for the phases of observations reported here.

A realistic error estimate on a period determination is always difficult to
obtain. Here, we use a rather straightforward method to give a rough error
estimate on the period: the width of the {\sc pdm} minimum is a measure for the
spread on the ``acceptable'' periods, i.e. the periods for which the
corresponding phase diagrams are still acceptable. This width is
$\sim$\,3\,10$^{-5}$\,c/d in frequency space, resulting in an uncertainty
of $\pm$0.2\,d on the period. As an extra check, we performed an additional
frequency analysis on the 260 V$_{\rm M}$\,$-$\,R$_{\rm M}$ colour data points.
This analysis yielded a slightly shorter period (P\,=\,112.86\,d), but still
within the quoted error of $\pm$0.2\,d.

The conversion of the raw MACHO magnitudes to a standard photometric system
is not straightforward, since the two filters are very broad, and they are only
partly overlapping with the classical Johnson or Kron-Cousins filters
\citep[see Fig.~1 of][for the filter pass bands]{alcock99}. The conversion to
the standard Johnson-Kron-Cousins system is performed using the formulae (1),
(2), (5) and (6) of \citet{alcock99}. In a first step, only the observations
that are taken simultaneously in both bands, were calibrated to the
Johnson-Kron-Cousins system, since V$_{\rm M}$\,$-$\,R$_{\rm M}$ is needed to
perform the conversion. Then, the calibration was extended to {\em all} 725
V$_{\rm M}$ points, using a calibration relation that was inferred from the
calibration of the 260 simultaneous points. A phase diagram of the converted V
magnitude, and the converted V-R colour, is shown in
Fig.~\ref{fig:calibratedVphsdgrm}.

\begin{figure}
\resizebox*{\hsize}{!}{\includegraphics{./5893fig1.ps}}
\caption{The MACHO V and V-R phase diagram, converted to the standard
Johnson V and Kron-Cousins R, constructed with a period of 112.97 days, and a
zero phase at deep minimum at JD2448673.384. For the V-R colour diagram, only
the simultaneous measurements in both bands are shown. At the bottom, the
phases of the photometric and spectroscopic data are given. The symbols of the
spectroscopic data are as follows: the full triangles are low resolution
spectra presented in \citet{pollard00}; the open ones are discussed in
\citet{lloydevans04}; the phase of the UVES spectrum (0.93) is shown with a
hexagon.}\label{fig:calibratedVphsdgrm}
\end{figure}

From Fig.~\ref{fig:calibratedVphsdgrm} it is clear that the phase diagram
displays a large dispersion around the mean curve, especially around the
two minima. This dispersion is caused by cycle-to-cycle variations. Note that
the colour variations are much more stable over the covered cycles. Such
cycle-to-cycle behaviour in light and colour curves is often observed in
RV Tauri variables \citep[e.g.][]{pollard96}.

\subsection{Near-infared photometry}
Near-infrared photometry was obtained with the Mk III Infrared Photometer and
chopping secondary at the Cassegrain focus of the 1.9\,m reflector of the
South African Astronomical Observatory by one of us (KRP). This photometry
was complemented by near-IR survey photometry of 2MASS and DENIS. All near-IR
data, together with their JD and phase, are gathered in
Table~\ref{tab:allnearirdt}.

\begin{table}
\caption{Optical Geneva and near-IR photometry of MACHO\,47.2496.8, together
with their JD and phase. The Geneva R and I are from the Gunn resp. Cousins
photometric systems.}\label{tab:allnearirdt}
\begin{center}
\begin{tabular}{rrrrrrrr}
\hline\hline
   JD     & Phase &   U   &  B    &   V    &   R  & I\\
\hline
\multicolumn{7}{c}{Geneva}\\
2453759.6 & 0.02 & 19.15 & 16.81 & 15.94 & 15.18 & 14.66 \\
\hline\hline
   JD     & Phase &   I   &  J    &   H    &   K  &\\
\hline
\multicolumn{7}{c}{SAAO}\\
2450437.4 &  0.62 &       & 13.18 &  12.67 &  12.54 &\\
2450438.3 &  0.62 &       & 13.20 &  12.56 &  12.29 &\\
Mean      &  0.62 &       & 13.19 &  12.61 &  12.41 &\\
$\sigma$  &       &       &   .04 &    .04 &    .05 &\\
\hline
\multicolumn{7}{c}{2MASS}\\
2451111.8 &  0.58 &       & 13.12 &  12.71 &  12.51 &\\
$\sigma$  &       &       &   .03 &    .04 &    .04 &\\
\hline
\multicolumn{7}{c}{DENIS}\\
2450377.8 &  0.09 & 14.02 & 13.22 &        &  12.53 &\\
$\sigma$  &       &   .03 &   .08 &        &    .13 &\\
\hline
\end{tabular}
\end{center}
{The Geneva R can be converted to R$_C$, the Cousins R magnitude, by the
conversion forumula from \citet{schombert90}, yielding R$_C$\,=\,14.89.}
\end{table}

\subsection{Optical CCD photometry with Euler}\label{sect:eulerpht}
Optical CCD photometry in five different bands was collected with the C2 camera
at the 1.2m Euler telescope on La Silla on 23/24 January, 2006. The filters that
were used are the Geneva U, B and V, completed with a Gunn-R and a Cousins-I
filter. Absolute photometry was derived by using exposures of the standard
stars HD\,47645 and SAO\,131547 that were taken immediately before and after
the MACHO\,47.2496.8 frames. This absolute calibration was cross-checked by the
extraction of two stars on the LMC-frame with published photometry which are
situated less than 4\,$\arcmin$ from MACHO\,47.2496.8: CSI-67-04552\,3
\citep[filters U, B and V,][]{schmidtkaler99} and MACHO\,47.2496.19
\citep[filters V and R,][]{keller02}. Taking into account that there are several
transformation formulae involved in the conversion of the Geneva and Gunn
filters to the Johnson-Cousins system \citep{schombert90, harmanec01}, the
magnitudes of the two check-stars are very close to the published ones.

Since there is a nearby star at approx. 2$\arcsec$, the extraction of
MACHO\,47.2496.8 was by no means easy. We corrected the pixels of
our target that are affected by this nearby star by their point symmetric
counterparts on the unaffected side of the photocenter. This induces an extra
uncertainty in the derived magnitudes, but, since the corrected pixels are
situated at the boundary of the psf, this uncertainty turned out to be not
larger than 0.05\,magn. The photometry is given in Table~\ref{tab:allnearirdt}.
The phase of the Euler observations, 0.02, has an estimated error of
$\sim$0.07, due to the quite large time gap between the MACHO photometry (on
which the period is based) and the C2-Euler observations. Note that the
MACHO photometry is not affected by this nearby star, since the latter star
has its own MACHO identification: MACHO\,47.2496.21.

\subsection{Spectral Energy Distribution}\label{subsect:sed}
The photometry from Table~\ref{tab:allnearirdt} was used to construct a Spectral
Energy Distribution of MACHO\,47.2496.8. The total reddening E(B-V) was
determined by minimising the difference between the magnitudes and a reddened
model atmosphere. For this model atmosphere, we used the parameters that were
determined in our abundance analysis (Sect.~\ref{subsect:atmosphprmtrs}). Note
that the optical Geneva photometry and the UVES spectrum from which the model
parameters are derived, differ less than 0.1 in phase. Such a small phase
difference is expected to result in only a small shift in atmospheric
parameters. The result can be found in Fig.~\ref{fig:sedphtmtr}; an
E(B-V)\,$=$\,0.44 was found. Due to the presence of the innumerable spectral
lines in the model atmosphere, the specific passbands of the filters used were
taken into account (Geneva system: {\tt http://obswww.unige.ch/}, DENIS:
\citealt{fouque00}, SAAO: \citealt{glass73}). The integration of the scaled
model combined with an LMC distance of 50\,kpc, yields a luminosity of
$\sim$5000\,L$_{\odot}$ (M$_{\rm bol}$\,$\simeq$\,$-$4.5).

A specific problem arose for the I magnitude. The Cousins I taken with Euler
turned out to be suspiciously low. The Cousins I was the only magnitude
that could not be checked with a star on the CCD frame itself (see
Sect.~\ref{sect:eulerpht}). The DENIS-I magnitude --in gray on
Fig.~\ref{fig:sedphtmtr}-- could not be reconciled with the other optical
photometry as well, possibly attributable to a phase shift. We did not take
either I magnitude into account in the minimisation.

\begin{figure}
\resizebox*{\hsize}{!}{\includegraphics{./5893fig2.ps}}
\caption{The spectral energy distribution (SED) of MACHO\,47.2496.8. Diamonds
are the measured magnitudes (converted to fluxes): Geneva U, B, V and Cousins
R taken with C2+Euler, I from DENIS (in gray), and SAAO J, H, K (see also
Table~\ref{tab:allnearirdt}). The MARCS model is shown in gray, while a smoothed
version is shown in a full black line. The minimisation is made using the
unsmoothed model in combination with the specific passbands of the photometric
filters involved. The I magnitude could not be fitted, and is excluded in the
minimisation. Possibly a phase difference is causing this discrepancy.}\label{fig:sedphtmtr}
\end{figure}

We made an additional SED with the MACHO photometry, confined to those
measurements with a a phase close to the UVES phase (difference $<$\,0.05),
since the model atmosphere parameters are based on the UVES spectrum. The
SED made with the MACHO V and R, completed with the DENIS I and the near-IR
JHK measurements, yielded a reddening of E(B-V)\,=\,0.33 and integration
of the scaled model yielded a total luminosity of $\sim$4600\,L$_{\odot}$
(M$_{\rm bol}$\,$\simeq$\,$-$4.4). The fit is, however, of a lower quality
than the fit in Fig.~\ref{fig:sedphtmtr}, hence we take the value of
5000\,L$_{\odot}$ as the final value for the luminosity of MACHO\,47.2496.8.

\subsection{Interstellar extinction}
The reddening derived in Sect.~\ref{subsect:sed}, is the {\em total} reddening,
and can have, besides the interstellar component, a circumstellar component as
well. The interstellar extinction towards the LMC is well studied in
literature. UBV photometry and spectral types of 450 OB stars in the western
half of the LMC
\citep{isserstedt75,isserstedt79,isserstedt82,ardeberg72, rousseau78,
crampton79, conti86,fitzpatrick88} give a mean E(B-V) of 0.13\,mag, using the
method and calibrations of \citet{fitzpatrick90}. There are larger values in OB
associations and a region of lower values in the North of the LMC. The region
surrounding MACHO\,47.2496.8 appears fairly uniform on the Digitised Sky Survey,
and the mean reddening of 16 stars within 30 arcmin is 0.11\,mag. However
\citet{zaritsky04} find that the distribution of reddening values for cool
stars differs from that of hot stars and is bimodal, such that stars have E(B-V)
near zero or near 0.15\,mag, depending on whether they lie in front of or behind
a widespread thin dust layer. We cannot place MACHO\,47.2496.8 or other carbon
stars relative to this dust layer and, therefore, have to assume that the
reddening is not significantly different from the average for carbon stars.

\section{High resolution observations}\label{sect:uvesbsrvtns}
High resolution, high signal-to-noise optical spectra of our programme star
were taken with the UVES spectrograph mounted on the VLT-UT2 (Kueyen)
telescope, in the program to obtain high-quality data of a
larger sample of post-AGB objects. The data were acquired in visitor
mode during ESO period \#74 by one of us (HVW). These observations fit in the
framework of our ongoing program to study the photospheric chemical composition
of stars in their last stages of evolution \citep[e.g.][]{reyniers04, deroo05}.
The resolving power of the UVES spectra varies between $\sim$60,000 and
$\sim$65,000. Spectra were taken with the chip unbinned. The spectral interval
covered and some other details about the observations are given in
Table~\ref{tab:observations}. Since there is another star at approx. 2\arcsec\
in the southwest of MACHO\,47.2496.8, the slit was placed perpendicular to this
direction. With this instrument setup, the contribution of the close
neighbour is negligible.

The reduction of our spectra was performed in the dedicated ``UVES context''
of the MIDAS environment and included bias correction, cosmic hit correction,
flat-fielding, background correction and sky correction. We used optimal
extraction to convert frames from pixel-pixel to pixel-order space. The spectra
were normalised by dividing the individual orders by a smoothed spline function
defined through interactively identified continuum points. For a detailed
description of the reduction procedure, we refer to \citet{reyniers02a}. In
Table~\ref{tab:observations}, we also list some indicative signal-to-noise
values of the final data product. Sample spectra can be found in
Figs.~\ref{fig:c2synth}, \ref{fig:zonderenmet} and \ref{fig:pbsnthss}. We note that the
most delicate step in the reduction procedure is the normalisation, especially
in the blue part of the spectrum, since the spectrum is so crowded that the
continuum is seldom reached. The continuum placement is the most important
source of uncertainty on the abundances derived from lines in this region.

\begin{table}\caption{Log of the high-resolution VLT-UVES observations. Small
spectral gaps occur between 5757\,\AA\ and 5833\,\AA\ and between 8521\,\AA\ and
8660\,\AA\ due to the spatial gap between the two UVES CCDs. Since continuum
spectral intervals are hardly found in the spectrum, the signal-to-noise ratios
S/N given in the rightmost column, are only indicative, and should be
interpreted more as lower limits than as fixed values.}\label{tab:observations}
\begin{center}
\begin{tabular}{ccccc}
\hline\hline
 date & UT    & exp.time & wavelength & S/N \\
      & start &  (sec)   & interval (\AA) &     \\
\hline
\multicolumn{5}{c}{VLT-UT2\,+\,UVES}\\
\hline
 2005-02-08 & 02:49 & 7200 & 4780$-$6808 & 70 \\
 2005-02-09 & 00:30 & 7200 & 3758$-$4983 & 40 \\
 2005-02-09 & 00:30 & 7200 & 6705$-$10084 & 80 \\
\hline
\end{tabular}
\end{center}
\end{table}

\section{Abundance analysis}\label{sect:abundancenlss}
\subsection{Carbon rich model atmospheres}
Before the actual determination of the atmospheric parameters, a new grid of
models for cool carbon-rich stars was calculated with the MARCS code, using
opacity sampling in 11\,000 frequency points. Atomic, diatomic and polyatomic
(C$_2$H$_2$, HCN, and C$_3$) opacities were included in addition to the
continuous ones in the model atmosphere computations. The models are
hydrostatic, spherically symmetric and computed under the assumption of LTE;
convective energy transport is included using a Mixing Length Theory (MLT)
formulation. Further details on the carbon-star model atmospheres will be given
in \citet{jorgensen06}; the current grid of models is described by
\citet{gustafsson03}. The sub-grid used here was computed for a rather wide
range in T$_{\rm eff}$, log g, overall metallicity and C/O ratios; the stellar
mass was set to 1 M$_\odot$.

\subsection{Atmospheric parameters}\label{subsect:atmosphprmtrs}
The precise determination of the atmospheric parameters was by no means
straightforward. The main difficulty was the lack of existing comparison
spectra. Due to the high C/O ratio as inferred from the strong C$_2$ bands,
the spectrum of MACHO\,47.2496.8 mimics the spectrum of a cooler carbon star
in those spectral regions where molecular lines dominate. The atomic
transitions, however, indicate a significantly higher temperature than the
typical carbon AGB star temperatures (2500-3500\,K). The presence of the
molecular lines itself points to a temperature lower than the galactic F-type
s-process enriched post-AGB stars.

The final atmospheric parameters were derived by an iterative process of
fitting specific spectral regions and fine-tuning the parameters consecutively.
These specific regions are carefully chosen in the sense that they contain
spectral features strongly depending on the parameters, like lines of different
ionisation stages of the same element. Also the wings of the Balmer lines
H$\alpha$ and H$\beta$ were fitted. The final parameters that were adopted
further in the analysis are: T$_{\rm eff}$\,=\,4900\,K, $\log g$\,=\,0.0,
$\xi_t$\,=\,3.5\,km\,s$^{-1}$ and model metallicity [M/H]\,=\,$-$1.5. An
additional and independent check was made by an equivalent width study of
selected iron lines. The search for clean, unblended lines is not easy in
the crowded spectrum of MACHO\,47.2496.8, but a detailed study of 8
Fe\,{\sc i} lines and 5 Fe\,{\sc ii} nicely confirms the atmospheric
parameters as derived by the spectrum synthesis iteration.

The procedure of finding the atmospheric parameters of MACHO\,47.2496.8 was
also followed in previous analyses of very similar stars
\citep{abia02, delaverny06}. We refer to the detailed error analyses in those
papers for error estimates on the parameters. Here we only remind that
the typical errors are as follows: $\pm$250\,K on T$_{\rm eff}$, $\pm$\,0.5
on $\log g$, 1\,km\,s$^{-1}$ on the microturbulent velocity $\xi_t$ and
5\,km\,s$^{-1}$ on the macroturbulent velocity. The latter parameter does
not influence the line strengths, but only the line profiles, and is only
used to better match synthetic and observed spectra in the spectral syntheses.

\subsection{Spectral regions}\label{sect:spectralrgns}
We have analysed in full detail several spectral ranges from 4000\,\AA\ to
8000\,\AA. Since the molecular lines of the carbon bearing molecules are
comparable in strength to those in carbon stars, we particularly focussed our
spectral syntheses on those spectral regions that are also used in the analysis
of the cooler galactic carbon stars \citep[see e.g.][]{abia02,delaverny06}. For
these regions, line lists are carefully composed and these are discussed in
Section 3 of \citet{delaverny06} and will not be repeated here. In general,
however, the atomic data of many s-process transitions occuring in the whole
spectral region covered by our spectra, are not known to a good precision, which
prevents accurate quantitative abundance studies. The most important regions
are (i) between 4750\,\AA\ and 4950\,\AA\ for the s-process elements and the
mean metallicity, (ii) 6700-6730\,\AA\ for the Li line, (iii) 4050-4060\,\AA\
for Pb, (iv) 4260-4270\,\AA\ for Tc, (v) the C$_2$ band head around 4737\,\AA\
for the carbon abundance and isotopic ratio $^{12}$C/$^{13}$C (vi) the
CN complex between 8000 and 8100\,\AA\ for the N abundance and as an
additional tool for the carbon isotopic ratio. Theoretical spectra were
computed with the TurboSpectrum code
\citep{alvarez98, plez92a, plez92b, plez93} in spherical geometry. The
macroturbulence used ranges between 10 and 20\,km\,s$^{-1}$.

The results of our abundance analysis are summarised in
Table~\ref{tab:absrslts}, and are also graphically presented in
Fig.~\ref{fig:elfevlsn_jan06}. The first column in Table~\ref{tab:absrslts}
gives the solar abundances $\log\epsilon_{\odot}$ of the elements that were
studied; the second one contains the actual ions; in the third one the method
of abundance determination is given (ss for spectrum synthesis and ew for the
equivalent width method); the fourth column gives the absolute abundances
derived $\log\epsilon$\,$=$\,$\log$(N(el)/N(H))+12; $\sigma_{\rm ltl}$, the
fifth column is the line-to-line scatter of the $n$ lines used (sixth column);
the last column gives the abundance relative to iron [el/Fe]. The solar
abundances needed to calculate the [el/Fe] values are taken from
\citet{grevesse98}, except: N \citep{hibbert91}, Mg \citep{holweger01}, La
\citep{lawler01}. Despite the fact that there are more recent values for some
of the solar abundances (especially for the solar CNO), we take these references
to ensure as much as possible consistency with our previous analyses, to be
able to compare abundance results adequately.

Errors on the reported abundances are difficult to assess, since very different
sources can contribute to the total error, and it is often very difficult
to perform an adequate error analysis. Main sources of error certainly include
continuum placement, undetected molecular and/or atomic features, an uncertain
effective temperature and inaccurate $\log(gf)$ values. For error estimates on
the reported abundances, we refer again to the error analyses in
\citet{abia02} and \citet{delaverny06}. In Fig.~\ref{fig:elfevlsn_jan06},
typical error bars are drawn, based on the number of lines used: if only one
line is used, an error of 0.3\,dex is applied, if more than one line is used,
an error of 0.2\,dex is assumed. The latter error estimate is justified if one
assumes that the error on an abundance based on $n$ lines, goes as
$\sqrt{\sum_i\sigma_i^2}/n$. In the following subsections, we will briefly
discuss our main findings for the different elemental groups.

\begin{table}
\caption{The abundance results for MACHO\,47.2496.8. The explanation of the
different columns is given in the text (Sect.~\ref{sect:spectralrgns}). At the
bottom, the usual s-process indices, together with metallicity, are given. More
information on the calculation of these indices is found in the
Sect.~\ref{sect:sprocesssbsctn}. The elements C and O are not separately
included in the table due to the specific difficulties for these elements
that are discussed in Sect.~\ref{subsect:cno}.}\label{tab:absrslts}
\begin{center}
\begin{tabular}{rlcrrrr}
\hline\hline
\multicolumn{7}{c}{\rule[-0mm]{0mm}{5mm}{\Large\bf MACHO\,47.2496.8}}\\
\multicolumn{7}{c}{\bf MARCS model}\\
\multicolumn{7}{c}{\bf with main parameters}\\
\multicolumn{6}{c}{
$
\begin{array}{r@{\,=\,}l}
{\rm T}_{\rm eff} & 4900\,{\rm K}  \\
\log g  & 0.0\ {\rm(cgs)} \\
\xi_{\rm t} & 3.5\ {\rm km\,s}^{-1} \\
{\rm [M/H]} & -1.5 \\
\log(\epsilon({\rm C}) - \epsilon ({\rm O})) & 7.98
\end{array}
$
}&\\
\hline
$\log\epsilon_{\odot}$&ion&meth.&$\log\epsilon$&$\sigma_{\rm ltl}$&n&[el/Fe]\\
\hline
1.10 &Li\,{\sc i}   & ss &$<$1.5 &       & 1  &       \\
\hline
7.99 &N\,{\sc i}    & ss &$<$7.45&       &    &$<$0.88\\
\hline
6.33 &Na\,{\sc i}            & ss &  5.2  &       & 1  &  0.3  \\
7.54 &Mg\,{\sc i}            & ss &  6.4  &       & 1  &  0.3  \\
6.36 &Ca\,{\sc i}            & ss &  4.4  &       & 1  & $-$0.5  \\
5.02 &Ti\,{\sc ii}  & ss &  3.55 & 0.05  & 2  & $-$0.05 \\
7.51 &Fe\,{\sc i}   & ew &  5.98 & 0.10  & 8  & $-$0.11\\
7.51 &Fe\,{\sc ii}  & ew &  6.09 & 0.09  & 5  &       \\
6.25 &Ni\,{\sc i}            & ss &  4.8  & 0.00  & 2  &  0.0  \\
4.60 &Zn\,{\sc i}            & ss &  3.4  &       & 1  &  0.2  \\
\hline
2.24 &Y\,{\sc ii}   & ss &  1.95 & 0.1   & 4  &  1.13 \\
2.60 &Zr\,{\sc ii}  & ss &  2.5  &       & 1  &  1.3  \\
\hline
1.13 &La\,{\sc ii}  & ss &  1.85 & 0.09  & 9  &  2.14 \\
1.58 &Ce\,{\sc ii}  & ss &  2.24 & 0.10  &23  &  2.08 \\
0.71 &Pr\,{\sc ii}  & ss &  1.46 & 0.15  &12  &  2.17 \\
1.50 &Nd\,{\sc ii}  & ss &  2.20 & 0.09  &20  &  2.12 \\
1.01 &Sm\,{\sc ii}  & ss &  1.50 & 0.15  &12  &  1.91 \\
\hline
0.88 &Hf\,{\sc ii}  & ss &  1.5  &       & 1  &  2.0  \\
1.11 &W\,{\sc i}             & ss &$<$1.3 &       & 1  &$<$1.6 \\
1.95 &Pb\,{\sc i}            & ss &$<$2.6 &       & 1  &$<$2.1 \\
\hline
2.60 & Rb\,{\sc i}           & ss &\multicolumn{4}{l}{not detected} \\
\hline
 & & \multicolumn{2}{c}{\bf summary}& &\\
 &\multicolumn{2}{l}{[Fe/H]\,$=$\,$-$1.42}&\multicolumn{2}{l}{[hs/ls]\,$=$\,$+$0.90}&\\
 &\multicolumn{2}{l}{[ls/Fe]\,$=$\,$+$1.22}&\multicolumn{2}{l}{}&\\
 &\multicolumn{2}{l}{[hs/Fe]\,$=$\,$+$2.11}&\multicolumn{2}{l}{[Pb/hs]\,$\le$\,0.0}&\\
\hline
\end{tabular}
\end{center}
\end{table}

\begin{figure}
\resizebox*{\hsize}{!}{\includegraphics{./5893fig3.ps}}
\caption{The abundances of MACHO\,47.2496.8 relative to iron [el/Fe].}\label{fig:elfevlsn_jan06}
\end{figure}

\subsection{CNO}\label{subsect:cno}
Apart from the ``classical'' atmospheric parameters T$_{\rm eff}$ and $\log g$,
the C/O ratio or, more specifically, the difference between the C and O absolute abundances,
 is by far the most important ``extra'' parameter determining the
spectrum of a cool carbon-rich star. Unfortunately, it is impossible to
determine this difference accurately, since the O abundance cannot be determined
independently; spectral syntheses are very similar for different C and O
abundances, as long as the difference $\epsilon$(C)-$\epsilon$(O) is kept more
or less constant (even within 1 dex of variation of both abundances figures). The reason is that extra C and O atoms which  are added to the
photosphere in similar amount, immediately combine in the strong
CO-bond. Therefore, only a lower limit could be derived for the C/O ratio:
C/O\,$>$\,2. The carbon isotopic ratio is easier to determine and from the
synthesis of the band head region around 4737\,\AA\ (Fig.\ref{fig:c2synth}),
this ratio was found to be $^{12}$C/$^{13}$C\,$=$\,200\,$\pm$\,25. The error of
$\pm$\,25 indicates the formal error due to model parameters (T$_{\rm eff}$,
$\log g$, [M/H]), adding the problem of the continuum location and the
uncertainties in the absolute C and O abundances.

An upper limit for the nitrogen abundance is derived from the CN complex at
8000\,\AA, and is found to be N/H\,$<$\,2.8\,10$^{-5}$
($\log\epsilon(N)$\,$<$\,7.45). The spectrum synthesis of this region
provides also an additional test for the $^{12}$C/$^{13}$C ratio. The value
of 200 is compatible with the $^{12}$CN/$^{13}$CN features in the 8000\,\AA\
range. The derivation of the carbon isotopic ratio is, however, much more
difficult in this 8000\,\AA\ region, since the $^{13}$CN features are much
weaker than in the 4730\,\AA\ range, and the uncertainty of the fit is
therefore very large.

\begin{figure}
\resizebox*{\hsize}{!}{\includegraphics{./5893fig4.ps}}
\caption{The VLT-UVES spectrum of MACHO\,47.2496.8 (points) around the C$_2$
4737\,\AA\ band head, overplotted with two spectrum syntheses with a different
$^{12}$C/$^{13}$C isotopic ratio.}\label{fig:c2synth}
\end{figure}

\subsection{Metallicity and $\alpha$-elements}
The metallicity was already roughly estimated in the iterative process of
the model atmosphere parameter determination. A careful synthesis of four clean
Fe\,{\sc i} lines yields $\log\epsilon$(Fe)\,=\,6.0, or [Fe/H]\,=\,$-$1.5.
We also calculated the abundance from 8 unblended Fe\,{\sc i} lines and 5
unblended Fe\,{\sc ii} lines through their equivalent width, and the results
agree nicely: $\log\epsilon$(Fe\,{\sc i})\,=\,5.98 and
$\log\epsilon$(Fe\,{\sc ii})\,=\,6.09. We will refer to the latter value as
``the'' metallicity of MACHO\,47.2496.8: [Fe/H]\,$=$\,$-$1.42. The iron
abundance derived from the Fe\,{\sc ii}-lines is chosen, since also at the
relatively low effective temperature of MACHO\,47.2496.8, the bulk of the iron
atoms in the photosphere is singly ionised. Note that the Fe proxies nickel
and zinc nicely follow the iron deficiency.

The $\alpha$-elements show surprisingly different abundances: Mg seems to be
enhanced by 0.3\,dex, while Ca is deficient by approximately 0.5\,dex. The
reason is not clear, but the difference is likely the initial composition of
the object without excluding an observational error due to blending: note that
we derive Mg and Ca abundances using only one line. The lighter
$\alpha$-elements, like Mg, are thought to be mainly produced during the
hydrostatic burning of massive stars, while the heavier $\alpha$-elements come
from explosive synthesis during SNe\,II. The abundances of the
$\alpha$-elements in MACHO\,47.2496.8 are in agreement with the observational
trends for the LMC that were recently derived by \citet{pompeia06}, so there is
no evidence for an intrinsic $\alpha$-enrichment or depletion. The same holds
for Na. Only Ca is somewhat lower than expected: \citet{pompeia06} predict
[Ca/Fe]$\sim$0 for a metallicity of [Fe/H]\,$=$\,$-$1.4, while we derived
[Ca/Fe]\,$=$\,$-$0.5 for MACHO\,47.2496.8.

\subsection{Lithium}
Although the region around the lithium doublet at 6708\,\AA\ is not very well
fitted, there is no evidence for an enhanced Li abundance. The upper limit
derived for Li is $\log\epsilon$(Li)\,$<$\,1.5. Note that the Li abundance
for a strongly s-process enriched object is difficult to determine, since the
Li doublet is strongly blended with a Ce\,{\sc ii} transition at 6708.10\,\AA\
\citep{reyniers02b}.

\subsection{S-process elements}\label{sect:sprocesssbsctn}
Although trace elements by nature, the absolute dominance of
transitions of s-process elements in the spectra is overwhelming.
This is illustrated in Fig.\ref{fig:zonderenmet}, in which
the synthesis is performed with and without s-process enhancement. S-process
elements are classically divided into the light ones noted ls (Sr, Y and Zr)
and the heavy ones, noted hs (Ba, La, Ce, Pr, Nd and Sm). Some elements show
a wealth of atomic transitions in the optical, like Ce and Nd, and the
abundances of these elements can be derived with great accuracy. Others, like
Sr and Ba, only produce a few strong resonance lines that are not suitable for
abundance determination purposes. This fact should be taken into account when
comparing individual s-process abundances. We could also derive an abundance
for the trans-Ba element hafnium (Hf), but it is based on only one line, so
it should be treated with caution.

We have also studied two resonance lines of Ba\,{\sc ii} to estimate the Ba
abundance. On top of being strongly saturated, the profiles are broader than
other atomic lines and  both lines show a blue-shifted component (14.6 and
15.5\,km\,s$^{-1}$, respectively). This is probably due to the dynamical
structure of the outer atmosphere of this pulsating star. Using only the
component at the same photospheric velocity as the other atomic lines, we
derive an upper limit of $\log\epsilon$(Ba)\,$<$\,2.8. We conclude, however,
that the special line profile makes the Ba abundance very uncertain.

\begin{figure*}
\resizebox*{\hsize}{!}{\rotatebox{-90}{\includegraphics{./5893fig5.ps}}}
\caption{The VLT-UVES spectrum of MACHO\,47.2496.8 (points) overplotted with two
spectrum syntheses. Both syntheses are made with the same model atmosphere,
only the abundances of the s-process elements differ. The synthesis in the
dotted line is made with solar abundances for the s-process elements (obviously
scaled down to the metallicity of MACHO\,47.2496.8), while the synthesis in the
full line is made with the enhanced s-process abundances as tabulated in
Table~\ref{tab:absrslts}. The observed spectrum is very well reproduced by the
spectrum synthesis, although there are clearly still some lines missing in the
line lists.}\label{fig:zonderenmet}
\end{figure*}

All s-process abundances are based on lines of singly ionised species.
Additionally, we have also searched for lines of doubly ionised Pr and Nd, which
are known to produce some strong lines in the spectra of enriched post-AGB stars
\citep[e.g.][]{reyniers04}. We found one Nd\,{\sc iii} line at 5294.099\,\AA\
and two lines of Pr\,{\sc iii} (at 5284.693\,\AA\ and 5998.930\,\AA) suitable
for abundance determination. The Nd\,{\sc iii} line yields the same
abundance as the one from the Nd\,{\sc ii} lines reported in
Table~\ref{tab:absrslts}; the two Pr\,{\sc iii} lines yield an abundance of
$\log\epsilon$(Pr)\,$=$\,1.85 and 2.26 respectively, and are much less
consistent with their singly ionised counterparts. It is not clear why
the discrepancy ($\sim$0.6\,dex) is so large.

In order to characterize the s-process pattern, and to be able to adequately
compare the observed pattern with other s-process enriched stars, three
s-process indices are usually defined: [ls/Fe], [hs/Fe] and [hs/ls].
Which specific elements are taken into account to determine these indices,
are, unfortunately, author-dependent, and are mainly just determined by the
elemental abundances that are obtained in the analysis. Here, we define the
ls-index as the mean of Y and Zr; the hs-index as the mean of La, Ce and Nd;
and obviously [hs/ls]$=$[hs/Fe]$-$[ls/Fe]. The elements Pr and Sm are excluded
from the hs-index to be able to compare with other s-process enriched stars.
Indeed, in many of the s-process studies, abundances for these elements are
lacking, and hence they are not incorporated in the indices. The resulting
indices are given at the bottom of Table~\ref{tab:absrslts}.

\subsection{Technetium}\label{sect:technetiumsbsctn}
The presence of technetium (Tc, Z\,=\,43) is a well known indicator that a star
is currently undergoing dredge-ups on the AGB phase, or that it has just left
this phase, since the half-life of $^{99}$Tc is $\sim$\,2$\times$\,10$^5$\,yr.
The detection of Tc is, however, complicated since all available lines are
quite weak, and they are often blended by much stronger atomic and/or molecular
lines. One of the lines that is often used in abundance studies of AGB stars,
is the resonance line at 4262.27\,\AA. The continuum placement is the main
source of uncertainty in this crowded spectral region. Moreover, at the
effective temperature of MACHO\,47.2496.8, the Tc line is intrinsically too weak
to see a clear difference in the synthesized line for different abundances.
We have to conclude that Tc cannot be used for MACHO\,47.2496.8 as a criterion
for the intrinsic enrichment.

\subsection{Niobium}\label{sect:niobiumsbsctn}
Besides Tc, there is another element whose abundance can be used as a criterion
to determine whether the star is intrinsically or extrinsically enriched:
niobium. Nb, which has only one stable isotope, is exclusively produced by the
decay of $^{93}$Zr (half-life $\tau_{1/2}\sim 1.5\times 10^6$ yr) and therefore
Nb populates the stellar surface only million years after the s-process elements
have been dredged-up. As a consequence, intrinsically (post-)AGB stars have
a Nb abundance much lower than extrinsically enriched stars for which
[Nb/Zr]\,$\simeq$\,0. For intrinsically enriched stars, the [Nb/Zr] abundance
depends only very slightly on the metallicity, and is predicted to be
[Nb/Zr]\,$\simeq$\,$-$1.0 \citep{bisterzo06}. For MACHO\,47.2496.8, we checked
all available Nb\,{\sc i} and Nb\,{\sc ii} lines in the spectrum, but
unfortunately none of them is suitable to derive a reliable abundance or upper
limit, since they are all situated in the blue part of the spectrum for which
the molecular veiling is most severe. There is one Nb\,{\sc ii} line at
4789.89\,\AA\ that could give an estimate for the upper limit. Again, the
continuum position is the main source of uncertainty in this spectral
region. Also, the blend in the immediate vicinity of the Nb
line at $\sim$4790.5\,\AA\ is clearly lacking in our line list. The derived
upper limit of [Nb/Zr]\,$\le$\,$-$0.3 is therefore very uncertain, but points
rather to an intrinsic than an extrinsic nature. Spectra taken in a hotter
phase might be more suitable to study this Nb line in more detail.

\subsection{Lead}\label{sect:leadsbsctn}
The end point of the s-process path is situated at lead and bismuth. Since the
discovery of the so-called ``lead stars'' by \citet{vaneck01}, lead has become
a very important issue in the study of the s-process. Unfortunately, lead
has only a few lines in the optical region, and they are all situated in
crowded regions in the blue spectral domain. In MACHO\,47.2496.8, only the line
at 4057.81\,\AA\ is accessible, and even there the blending by molecular lines
and s-process elements is severe. As a consequence, the main source of
uncertainty of the Pb synthesis in this region is the continuum placement.
Therefore, we can only derive an upper limit for the Pb abundance:
$\log\epsilon$(Pb)\,$<$\,2.8, as illustrated in Fig.~\ref{fig:pbsnthss}.

\begin{figure}
\resizebox*{\hsize}{!}{\includegraphics{./5893fig6.ps}}
\caption{Synthesis of the Pb\,{\sc i} line at 4057.81\,\AA. The exact position
of the continuum is far from clear in the vicinity of the line, which makes it
only possible to derive an upper limit for the Pb abundance.}\label{fig:pbsnthss}
\end{figure}

\section{Discussion: intrinsic or extrinsic?}\label{sect:discussionntrxtr}
Our abundance analysis (Table~\ref{tab:absrslts} and Fig.~\ref{fig:elfevlsn_jan06})
clearly shows that MACHO\,47.2496.8 is a metal poor, but strongly
s-process and carbon enriched object in the LMC. Contrary to Galactic
RV\,Tauri stars (see Sect.~\ref{sect:introdctn}),
there is no evidence for depletion of refractory
elements. In a carbon-rich (C/O$>1$) environment, ZrC is likely to condense
first \citep{lodders99} followed by TiC and SiC. For MACHO\,47.2496.8,
the abundances of these elements follow the trend which is expected from
a star that underwent an efficient dredge-up while evolving on the AGB,
so no depletion has taken place. To determine whether this enrichment is
intrinsic or extrinsic is not straightforward but in the following we argue
in favour for the intrinsic interpretation.

\subsection{Abundances}

From Sect.~\ref{sect:technetiumsbsctn} it is clear that the spectral feature,
Tc, that is classically used to determine whether a star is
intrinsically or extrinsically enriched, cannot be used for MACHO\,47.2496.8,
mainly due to its relatively high T$_{\rm eff}$. An alternative indicator, the
[Nb/Zr] abundance discussed in \ref{sect:niobiumsbsctn}, is also difficult to
quantify, but might have some potential for spectra that are taken in a hotter
phase.

\subsection{Carbon star luminosity function}
Since carbon star counts in the Magellanic Clouds are considered to be nearly
complete, the luminosity functions for the carbon stars (CSLF) in the Clouds
can be constructed. In the LMC, 7750 carbon stars are detected, and a histogram
of the observational CSLF can be found in e.g. Fig.~6 of \citet{groenewegen06}.
This histogram does not indicate a clear faint limit to the luminosity function
of the N-type carbon stars.
The reproduction of the CSLF of the LMC by detailed nucleosynthetic models
is a long standing problem, since these models do not succeed in producing
the carbon stars at the low luminosity end of the CSLF. Recently, it has been
argued that the low-luminosity end of the CSLF is populated by first
giant-branch stars that are enriched by mass transfer from a former AGB
companion. This idea was quantitatively worked out in \citet{izzard04}. In
this paper, the transition between an extrinsically enriched carbon star and
a genuine AGB carbon star is situated around M$_{\rm bol}$\,$\sim$\,$-$4.
Consequently, the bolometric magnitude M$_{\rm bol}$\,$\simeq$\,$-$4.5 of
MACHO\,47.2496.8, inferred in Sect.~\ref{sect:photomtr}, does not provide
a strong constraint whether the object is either intrinsically or extrinsically
enriched.

We compared the flux of our program star to the flux of the N stars by
integrating over the wavebands B to K. The mean figure for MACHO\,47.2496.8
has been calculated assuming that the ratio between maximum and intensity-mean
light, calculated for V and R using the intensity-scaled light curves from the
MACHO website, applies to all wavelengths. This is a conservative assumption,
as the amplitude is probably less in the near infrared. The relative flux in
BVRI for the N stars has been assumed to be the same as for galactic N stars,
using the data of \citet{walker79}. Fluxes have been calculated in magnitudes
on an arbitrary scale, and show that MACHO\,47.2496.8 is 0.09 mag (at minimum
light) and 0.30 mag (at maximum light) brighter than the faint limit for N
stars in the LMC.

It is clear that MACHO\,47.2496.8 is located at the low luminosity end
of the carbon star luminosity function of the LMC. Its metallicity is,
however, quite low compared to the bulk of the LMC stars. A better
luminosity function may therefore come from the SMC where it is well
known that the CSLF is shifted to lower luminosities
\citep{groenewegen99}. The low intrinsic metallicity therefore
favours even more the intrinsic nature of the s-process enrichment.
In fact, at the metallicity of MACHO\,47.2496.8 ($\sim$ Z$_\odot/30$),
the minimum luminosity for the formation of an AGB carbon star may be
slightly lower than M$_{\rm bol}\sim -4.0$, the exact value depending on
the mass-loss parametrization \citep[e.g.][]{straniero03}.

\subsection{Comparison with galactic CH stars}\label{sect:CH}
CH-stars are metal poor, carbon rich giants with spectral types from G to K,
with enhanced CH, C$_2$ and s-process elements relative to normal giants.
CH-stars have typically also large radial velocities of
$\sim$100\,km\,s$^{-1}$. It is likely that all CH-stars are binaries in which
the present primary has gained processed material from a formerly-AGB companion,
now a white dwarf \citep{mcclure90}. The first accurate quantitative abundance
analyses were done by \citet{vanture92a, vanture92b, vanture92c}. He found that
the s-process abundance pattern of the CH-stars is characterised by large
s-process enhancements and large [hs/ls] ratios of $>$+0.9. Their metal
deficiency, carbon enrichment and s-process pattern are similar to
MACHO\,47.2496.8, and they are therefore ideal galactic comparison stars. The
majority of CH-giants, however, show very low carbon isotopic ratios, typically
$^{12}$C$/^{13}$C\,$<$\,10 \citep{vanture92a}, which is not seen in
MACHO\,47.2496.8.

More recent abundance analyses of CH-stars \citep{vaneck01, vaneck03, aoki01,
aoki02} confirmed the older results of \citet{vanture92c}, and focussed on the
detection of an enhanced lead content, which was predicted in different
nucleosynthetic AGB models \citep[e.g.][]{gallino98, goriely00}. As first
discovered by \citet{vaneck01}, a subgroup of the CH-stars does show this
predicted Pb enhancement (typically [Pb/hs]\,$\simeq$\,$+$1), but there are
also CH-stars that are not compatible with the predictions, showing [Pb/hs]
ratios that are more than one magnitude lower than predicted
\citep[see e.g. Fig.~4 in][]{vaneck03}.

The Pb abundance of MACHO\,47.2496.8 is very uncertain, and in
Sect.~\ref{sect:leadsbsctn}, we were only able to derive an upper limit of
[Pb/hs]$\sim$0. Therefore MACHO\,47.2496.8 is considered as a ``lead-low''
star. Nevertheless, the low [Pb/hs] ratio as well as the other s-process
indices are still compatible with recent nucleosynthesis calculations in
low-mass AGB stars \citep{gallino06}.

\section{Conclusion}\label{sect:maincnclsns}
In this paper, we have presented our study of the brightest RV Tauri star
that was found in the MACHO experiment: MACHO\,47.2496.8 \citep{alcock98}. The
star is strongly pulsating with a peak-to-peak amplitude in V of
$\sim$1.4\,magn.
A SED constructed using recent CCD photometry taken with the
Euler telescope at La Silla, indicates a reddening of E(B-V)\,=\,0.44, while the
interstellar reddening towards this region in the LMC is E(B-V)\,=\,0.11.
The intrinsic bolometric magnitude M$_{\rm bol}$ calculated from the spectral
energy distribution is $-$4.5, placing the star in the low luminosity end of
the carbon star luminosity function of the LMC.

Our high-resolution, high signal-to-noise optical UVES spectra are unfortunately
taken in a cool phase. The main results of our detailed abundance analysis
performed by a careful synthesis of some regions that are already well studied
in galactic carbon stars, are
\begin{itemize}
\item a surprisingly low metallicity: [Fe/H]\,$=$\,$-$1.4, with no evidence of
depletion
\item a high C/O ratio, certainly larger than 2, and a carbon isotopic ratio
$^{12}$C/$^{13}$C of around 200
\item a large s-process enrichment with [ls/Fe]\,$=$\,$+$1.2, and [hs/Fe]\,$=$\,$+$2.1
\item a low Pb abundance [Pb/Fe]\,$\simeq$\,[hs/Fe]
\end{itemize}
We used a new grid of state-of-the-art MARCS models for cool carbon rich stars,
which was especially constructed for this analysis.

Although we cannot totally exclude that the star is extrinsically enriched by a
former AGB companion which should be seen now as a white dwarf, the enrichment
is likely of an intrinsic origin. The luminosity, although quite low, is still
compatible with an advanced phase of a very low-mass star, and the pulsations
are prototypical of an RV Tauri like object. Unfortunately, the star is too hot
to use technetium as a criterion of an in situ enrichment. Also the alternative
element suitable as an intrinsic/extrinsic test, niobium, cannot be used for
this star. New spectra, taken in a hotter phase when the molecular veiling is
absent, could enable a conclusive test concerning the intrinsic/extrinsic
dilemma.

With its low luminosity and certainly very low inital metallicity,
MACHO\,47.2496.8 represents the final evolution of a star which must have had
an initial mass very close to solar. To our knowledge, this is the first
detailed chemical analysis of a post-AGB star with a known distance and
accurate luminosity estimate. The large carbon enhancement and the very rich
s-process nucleosynthesis show that also very low-mass objects will undergo
strong chemical changes during AGB evolution.

\begin{acknowledgements}
It is a pleasure to thank Maria Lugaro and Axel Bona{\v c}i\'c Marinovi\'c,
who were immediately willing to test their latest models on our results,
which initiated a most promising collaboration. The authors would also like to
thank Oscar Straniero for the Nb prediction, Pieter Deroo for the help with the
construction of the SED, Sophie Saesen for the Euler observations and the
anonymous referee for the many useful comments that improved the paper
considerably. The Geneva staff is thanked for observation time on the Euler
telescope. This paper utilizes public domain data obtained by the MACHO Project,
and data from the Vienna Atomic Line Database. MR and LD acknowledge financial
support from the Fund for Scientific Research - Flanders (Belgium); CA has been
partially supported by the Spanish grant AYA2005-08013-C03-03; KE thankfully
acknowledges support by the Swedish Research Council.
\end{acknowledgements}

\bibliographystyle{aa}

redpajama_set_name: RedPajamaArXiv


text:
F-35 pilot: Forget drones, the skies still belong to fighter pilots
Hasard Lee | June 14, 2021
As a fighter pilot, I have a lot of respect for what Elon Musk has accomplished. His ability to not adhere to dogma has allowed him to revolutionize two industries through SpaceX and Tesla. Much like a physicist, he relies on first-principle science to solve problems, which allows him to see things from a fresh perspective. However, he is wrong about the fighter jet era being over.
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Elon Musk, chief engineer of SpaceX, speaks with U.S. Air Force Lt. Gen. John Thompson, Space and Missile Systems Center commander and program executive officer for space. (U.S. Air Force photo by Senior Airman Christian Conrad)
RELATED: WHY 5TH GENERATION 'MINUS' FIGHTERS ARE THE FUTURE
As a fighter pilot, my job is to not fall in love with the aircraft I fly, but to use it as a tool to accomplish a mission. We are constantly looking for ways to optimize our lethality while minimizing risk. If there is a better way to accomplish a mission, then it is our duty to use it. While I agree with Elon Musk that the future is drone warfare, I think we're a lifetime away from seeing a fully autonomous Air Force.
Unmanned Aerial Vehicles (UAVs) have fundamentally altered the way we train and fight. I've integrated with them extensively over my career and seen first-hand how valuable they are. Their persistence is unmatched—an MQ-9B recently flew for nearly 2 days without having to refuel. The sensors they carry are equally impressive, due to the weight savings from not having to keep a pilot alive. Perhaps most important, though, is that they don't put human lives at risk.
U.S. Air Force MQ-9 pilot and enlisted sensor operator conducting training. (U.S. Air Force photo by Airman 1st Class William Rio Rosado)
RELATED: DRONES WILL COMPETE WITH CREWED AIRCRAFT FOR AFSOC ARMED OVERWATCH PROGRAM
It's important to understand that these UAVs are not autonomous—there is someone, usually half a world away, controlling every move by the aircraft. They are a lot more, in effect, like scaled-up radio-control aircraft than they are like robots. As we move away from limited conflicts like Afghanistan and Iraq to near-peer adversaries with high-end capabilities, it's becoming increasingly difficult to maintain the integrity of that signal. This means that to replace manned fighters, these drones will need to be autonomous, or make decisions on their own, in order to be effective.
As Elon Musk is finding out, making an autonomous vehicle is incredibly difficult. While Tesla's autopilot can navigate reasonably well on highways, they have a much harder time in the city. There are so many edge cases (problems that only occur under extreme circumstances) involved in city driving that are nearly impossible to predict. When several of these one-in-a-thousand events happen simultaneously, the car's autonomous software becomes overwhelmed. Remember, these cars are operating in a highly regulated environment where the rules are clearly defined.
Combat is the most dynamic environment imaginable. The fog and friction of war prevent a full understanding of the battlefield. In addition, the enemy is specifically targeting your weaknesses. Teslas don't have to fight state actors that are specifically trying to make them crash.
Imagine a city that is more like "Mad Max," where there are adversaries painting street lines into telephone poles and shining lasers into the car's cameras—they wouldn't go a block without being disabled.
(U.S. Air Force photo/Staff Sgt. Marleah Robertson)
Related: VALKYRIE UCAV FLIES WITH F-22, F-35 FOR THE FIRST TIME IN DATA LINK TEST
The same is true for an autonomous drone—it not only has to be able to make decisions on its own, but it must overcome an adversary that is specifically targeting its weaknesses. And that is where the human brain thrives—coming up with dynamic and creative solutions to undefined problems.
The current Venn Diagram of manned and unmanned aircraft capabilities is so far apart that neither is close to being replaced. The future is finding ways for both to operate as seamlessly as possible.
Feature image: U.S. Air Force photo by Capt. Kip Sumner
Hasard Lee
Hasard Lee is a fighter pilot currently flying the F-35 Panther, the United States' newest 5th Generation stealth fighter. Prior to flying the F-35, he flew the F-16 Viper, including 82 combat missions. In his latest role, he was the Chief of F-35 Training Systems, developing innovative techniques to train future fighter pilots.
Hasard is a writer and speaker for Sandboxx. He also runs a YouTube channel that receives over 10 million views per month.
Follow Hasard Lee: Linkedin Youtube
Gerard says
The skies may still belong to pilots today, (that's as in manned aircraft). Tomorrow? They won't. Well, maybe not tomorrow, but soon. AI is being developed and deployed at a fast pace. Soon? Well soon it will just be too dangerous for men to fly against drones. We've been reading about this eventuality for generations now, for as long as people can remember Popular Science, and Popular Mechanics.
markedup2 says
There is, as Lee (why is his rank not given?) starts to admit, a performance cost to having pilots in planes. By and large, drones are not affected by the g-forces of flight. Many of the issues they do have are technologically addressable, which is one reason why mil-spec stuff is so expensive. Your laptop will not survive 10-g turns. Drones can have much larger performance envelope than pilots.
Other than that, I agree with the article. Humans are coming up short in the "brawn" department – just ask John Henry – but for now we're still ahead in the "brains" department.
Michael Long says
I do like my Tesla. It is a great car I like Elon Musk, he is making the world a better place. I also like having human operators in those aircraft and on the ground (at Creech AFB, not Nellis). However, the hype in performance and autonomy that Elon is famous for does not match reality. The car is very quick off the line, but not nearly as quick in reality as claimed. The car has great range, but not nearly as far as what is claimed. The car will drive itself to stay in its lane and hold speed and distance to cars ahead of the car. However, any small wrinkle and the car can be confused. Only in the most tightly controlled circumstances and with a certain set of underlying assumptions will the car perform at the stated limits.
In normal operating conditions, or combat conditions there are no controlled circumstances. In the future, as in the past, Stonewall Jackson and his II Corps WILL just show up out of nowhere as the XI Corps is making their supper. An IJN battle fleet WILL just show up out of nowhere when Halsey is off chasing enemy carriers. Elon has made this a better world, but I really do not want him peddling the next Hyperloop to replace our fighter squadrons.
C. Earl Jantzi says
And mistakes in a multibillion dollar aircraft are much more costly than a drone.
Lol. Yeah right.
Cobra1086 says
I absolutely agree. There will be counter systems to drones. Signals from half way around the world can be jammed. Cameras cant "feel" and respond as fast as the human brain can. There is limitations to remote piloted UAVs. The author is right. We are not quite there with remite control drones. Until real drones with true AI are in the sky, human piloted fighters are not out dated.
I agree, Its not over yet – but change is coming.
I think manned fighters will stay around but they will be more like the quarterbacks of the fight.
Some good evidence to support this is what Turkey has recently done with ground attack drones. How long before someone does the same thing in the air to air realm? Not long I suspect.
V says
There will always be a man in the loop, no one is going to allow AI war fighting drones to fire weapons with out ok from a human. Drones can do the mundane tasks, from ISR, tankers, to loyal wingman.
Fran says
I know nothing about flying,but I do so love watching my American pilots fly off carriers etc.. from posts on utube etc.. What I resent is people like the Musks of this world trying to take us to AI in planes, trains& automobiles. They trying to get me, a tax payer, to pay for tech that isn't ready for prime time. Nowhere in our realm is a hint we are ready. If they want to impress me figure out how do successful recycling, use the rest of our waste as fuel.
Big damage dave says
No one cares if we think its ready or not.
Technology simply moves on with us or without us.
john A irvine says
Shouldn't have Pilots wasted on driving current drones.. Knuckleheads even got crew rest! Soldiers needing CAS and pilot would be at Nellis AFB in the bathroom. Became to difficult for them to fly and manage drone ISR systems so they gave them a WSO or NCO…, Same tasks for both could be handled by an E-4 with 2 hours (training) playing and a bag of chips.., who never saw the drone. Fewer accidents, crashes and cost..,
Clement Khoo says
You're an idiot. Be serious. This is a life and death matter. Kudos to Capt Hasard.
RepublicansaredestoryingAmerica says
Of course this moron would say that. USAF pilots are the biggest idiots and liars in the service. Lowest recruiting standards too.
USAF said they didn't need a gun, than Vietnam happened. Brass said they didn't need IRST, than everyone but airforce had them until the Turkey-35 and it's already old tech compared to most pods.
The F15EX will be doing the jobs the Turkey should have been, and it'll be paired with drones to get it done.
David Kelly says
USAF pilots are the best and brightest in all of the United States Armed Forces, bar none!!! No one has higher standards!!!
Jonathan G Isernhagen says
Standards are one thing. Carrier qualification is something else.
BTW…the EVIL DEMOKKKRATS are destroying this country AND the World!!
IYAAYAS! says
You're an idiot!
Your a complete idiot. You moron.,you couldnt get past ground school much less basic flight training. Being a pilot isnt playing Xbox fool. Your comment illustrates your infantile IQ.
Agree, wholeheartedly.
Until AI becomes self aware, then teaching it threats, will mean it will always have an exploit that can be leveraged. Only when it becomes truly self aware, and sees threats the same way we do, it will never be able to fully generate a response to someone trying to erase it.
Not even sure GANs (Generational Adversarial Networks) can adapt fast enough to react to the kind of cunning a brain in a fighter will employ vs. AI that currently simply doesn't see "threats" the way we do.
Just my opinion, could be wildly wrong.
Raymond D Babcock says
AI will make mistakes. Most likely they will be worse than the mistakes people make.
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redpajama_set_name: RedPajamaCommonCrawl


text:
Lebanon tensions ease, official warns of "civil war"
by Dmitri Marine in All News, Middle Eastern News
This week, things turned for the worse in Lebanon, with violence erupting in Beirut. But both the government and the opposition seem to be showing maturity by calling for unity in Lebanon to prevent an outbreak of civil war.
This situation is very indicative of what is going on in Lebanon: the protests of recent months are not opportunistic, but realistic. There is a significant segment of the Lebanese population that dislikes the way the current government is handling the country. And instead doing things un-democratically, through terror, the disenchanted are taking peaceful means to voice their concerns and demands. No one can doubt that Hezbollah, a key player in the protests, is capable of acts of terror (and ones of magnitude). After all, it was Hezbollah that seriously challenged the reputation of the IDF this summer. However, Hezbollah has not been violent. There is no indication that the assassination of Pierre Gemayel, which occurred before the protests began, has been linked to the politically active group.
Nevertheless, some pro-government officials in Lebanon are saying the violence is the responsibility of protesters. Samir Geagea has accused the opposition of trying to take force by "force" and has said that the continuation of protests would lead to "civil war."
Gaegea has a point, in that if the government continues to dispute protesters' demands, violence will eventually break out. But it won't be the fault of the protesters, but Lebanon's government. Now is not the time to be stubborn. The opposition — and a large number of the Lebanese population — have shown this movement to be more than the Orange revolution, so widely publicized as a triumph for democracy, so it's time for Prime Minister Siniora to listen and stop demanding.
The PM has refused to negotiate with the opposition until protests cease.
Dmitri Marine blogs on Blogue North
2 users commented in " Lebanon tensions ease, official warns of "civil war" "
Global Voices Online » Blog Archive » Lebanon: Violence, Paris 3 and Cluster Bombs said,
in February 1st, 2007 at 5:32 am
[…] Dmitri Marine writes on the Blogger News Network about the same topic and does not see an imminent violent escalation of the situation: There is a significant segment of the Lebanese population that dislikes the way the current government is handling the country. And instead of doing things un-democratically, through terror, the disenchanted are taking peaceful means to voice their concerns and demands. No one can doubt that Hezbollah, a key player in the protests, is capable of acts of terror (and ones of magnitude). After all, it was Hezbollah that seriously challenged the reputation of the IDF this summer. However, Hezbollah has not been violent. […]
vibArbita said,
in November 16th, 2007 at 2:03 am
Two new studies show why some people are more attractive for members of the opposite sex than others.
The University of Florida, Florida State University found that physically attractive people almost instantly attract the attention of the interlocutor, sobesednitsy with them, literally, it is difficult to make eye. This conclusion was reached by a series of psychological experiments, which were determined by the people who believe in sending the first seconds after the acquaintance. Here, a curious feature: single, unmarried experimental preferred to look at the guys, beauty opposite sex, and family, people most often by representatives of their sex.
The authors believe that this feature developed a behavior as a result of the evolution: a man trying to find a decent pair to acquire offspring. If this is resolved, he wondered potential rivals. Detailed information about this magazine will be published Journal of Personality and Social Psychology.
In turn, a joint study of the Rockefeller University, Rockefeller University and Duke University, Duke University in North Carolina revealed that women are perceived differently by men smell. During experiments studied the perception of women one of the ingredients of male pheromone-androstenona smell, which is contained in urine or sweat.
The results were startling: women are part of this repugnant odor, and the other part is very attractive, resembling the smell of vanilla, and the third group have not felt any smell. The authors argue that the reason is that the differences in the receptor responsible for the olfactory system, from different people are different.
It has long been proven that mammals (including human) odor is one way of attracting the attention of representatives of the opposite sex. A detailed article about the journal Nature will publish.


The suggested benefits of prunes in the preservation of bone and joint health have been highlighted in a Channel 4 TV programme on superfoods.
Last month's Superfoods show showed a US astronaut who was 'sent to the moon on a prune'.
The programme revealed that NASA was committed to its astronauts eating a prune-rich diet as a possible intervention to counteract loss of bone density due to exposure to space radiation and weightlessness.
It followed on from research published last year in Scientific Reports, which indicated that eating prunes may be beneficial to counter the effects on bone of exposure to space radiation.
The programme also included an interview with Dr Bahram Arjmandi, professor and chair of the Department of Nutrition, Food and Exercise Sciences at Florida State University.
Based on research he has undertaken among post-menopausal women, Arjmandi claimed that eating a simple daily helping of around eight to 12 California prunes (100g) could support the maintenance of healthy bones and may even contribute to maximising bone potential.
"It appears that the inclusion of prunes in the diet can help to suppress – and in some cases, revert – the breakdown of bones, which tends to speed as people age," he said.
In addition, prunes have an EU health claim for contributing to normal bowel function.
The California Prune Board is currently engaged in its largest-ever clinical trial to deliver further research that links prunes and bone health.
"We will continue to educate the trade on the extensive health and nutritional advantages associated with the consumption of prunes," said European marketing director Esther Ritson-Elliott.


text:
Thriller tales (1940 -1962): Excellent Mystery Drama with an all-star cast including:
Charles Ruggles
Dane Clark
Suspense is one of the classics of old time radio. Some fans have special favorites in the thriller/chiller/macabre genre, but all will agree that Suspense did it best. The guiding light of this show was William Spier, who developed the formula into a human drama that attracted the finest of Hollywood's elite as well as the cream of radio's great actors.
Orson Welles was in many episodes, and Cary Grant was quoted in 1943, "If I ever do any more radio work, I want to it on Suspense, where I get a good chance to act." Spier's method with his show's stars was to keep them under-rehearsed, somewhat uneasy. In Suspense, as it were. He got great performances, and the show gained greater and greater popularity.
Text on OTRCAT.com ©2001-2011 OTRCAT INC All Rights Reserved-Reproduction is prohibited.
The Roma Wine sponsorship in 1943 allowed the show to create works that are a lasting part of the old time radio entertainment experience. All the production values were first class. The great Bernard Hermann did the musical scores. He previously had worked with Orson Welles in his Mercury Theater series, and went on to do of Alfred Hitchcock film fame. Lucian Moraweck did many of the greatest episode scores.
The "Man in Black" is your host, reminding one of the many thriller show presenters, but Suspensewas the best of the bunch, and never did the show lapse into over-the-top melodrama. William Spier was so deft in his weaving of the spell of Suspense, he was dubbed "the Hitchcock of the airwaves."
Through the years, various directors were enlisted to create the show. Anton Leader directed in the late 40s, and Norman Macdonnell, producer/developer of The Adventures of Phillip Marlowe and Gunsmoke did stints in the 50s. William M. Robson, another radio great known for his writer/director credentials, finished the series in Hollywood in the late 50s, but the show continued from New York with radio's best actors under the production/direction of Bruno Zirato, Jr.
"Radio's outstanding theater of thrills" was just that. It was not a show about crime or detection like many others, nor was it a melodramatic horror show. In quality and tone, it's closest rival was Escape. Throughout its long run, Suspensewas dedicated to the excellent script in which a normal person becomes involved in a situation that becomes beyond control. As the intro said, "We invite you to enjoy stories that keep you in …. SUSPENSE!
SUSPENSE also stars:
Loretta Young and many, many more!
For other similar series see also Dark Fantasy, Escape, Inner Sanctum, Adventures by Morse, Lights Out, Mysterious Traveler, Mystery in the Air, The Whistler, and Weird Circle. See also the compiled collection, Best of Suspense, which includes some of OTRCAT's favorite episodes from this epic series.
(Source = OTRCAT Suspense)


Khara E. House: Where is the Dream ... And Where are the Dreamers?
Where is the Dream ... And Where are the Dreamers?
In anticipation of Martin Luther King, Jr. Day 2018, I have been reading Dr. King's words as put down in history books and anthologies, the records of the great speeches of one of the greatest orators our nation has ever known. And I admit I have found myself longing for the opposite of Dr. King's wish shared in his Mountain Top speech delivered on the eve of his own assassination, in which he envisioned the Almighty asking him in which age he would like to live and found himself longing, beyond his own hope and history's reality, to live to see his own tomorrow.
Instead I find myself longing to be that proverbial fly on the walls of history. If I could I would pray myself to those days of walking among giants whose soft-spoken words of change and justice still echo through the caverns of the status quo and crack the mighty mountain of injustice which my forbearers climbed for me. I long to see the faces of those who dared to dream that a tomorrow they may never see would be a day worth dying for. I long to see the fire that blazed in the spirits of men and women who those standing against the unquenchable change they represented attempted to douse with water that only served to baptize their resolve. I long to be in the time of those who could not be stopped because, as the spiritual declared, up above their heads they heard music in the air, and the song it sang was of freedom.
Where is the dream? Dr. King spoke of a dream "deeply rooted in the American dream … that one day this nation will rise up, live out the true meaning of its creed: 'We hold these truths to be self-evident, that all men are created equal.'" His was a dream that swelled beyond the voices of those who would have seen in those days some small step forward and called for him and his people to be satisfied. And as King and those who marched and prayed, stood up and sat in, bled and hung, lived and died, knew … we know today that we are not satisfied, and our struggle is not over. The justice King called for was a justice that rolled like water. Today we see the rising tide, but it is not justice rolling over us but indifference, prejudice, and the hard-hearted call to "move on" where change has festered, and time rolled back upon itself. Today we shudder at the unknown, recoil from the marvel of a diverse humanity, and turn blind eyes to the same creative suffering that plagued our nation in the days our Constitution's promise of life, liberty, and the pursuit of happiness cracked and bled under the weight of systems pungent with prejudice, persecution, and brutal injustice.
And where are the dreamers? We are still here, but who would know it when we quiver at the thought of causing ripples where those who came before us made waves? Even I have let the dream of that brighter day become a shadow, a secret I keep to myself for fear that to share it will be unpopular and with it I, too, cast from the acceptability of public gaze. Today's dreamers have become the dream deferred of Langston Hughes, a dream that instead of exploding into action dries up like a raisin in the sun. I admit I am ashamed to call myself a child of the dream who has not heeded the words of my forefathers, one who has lost the way… one who has let the dream wither in the shadow of silence.
I come back to today and I bring with me the voices of those who have gone before me. The dream is not dead, and today I will not let it die. Today I say that though we face a tomorrow ripe with worry and fear and difficulty and pain, I, too, still have a dream. For too long our country has rationalized or averted our gazes from racism, racial, cultural, and social inequality, and institutional systems of oppression … but I still dream. For too long political disenfranchisement, economic inequities, and social injustices have gone unanswered … but I still dream. For too long our collective silence has given foothold to those who would divide us with hate and fear, who would steep our national dialog in the murky waters of divisive rhetoric and the blindness of bigotry, and who thrive on our willingness to pursue what is easy instead of what is right … but I still dream.
I dream that on this day we will return to the strength of Kings, to freedom's ring, and to lifting our voices and singing the harmonies of liberty, justice, and an ever brighter tomorrow. I dream that the faith of our past, and the hope of our tomorrow, will steady our hands and strengthen our feet as we march on toward that great victory our ancestors prayed into our reach. I dream that though the road ahead is long and paved in the blood marked progress of those who fought for a dream they would not live to see fulfilled, we will march on with courage and the strength of knowing that we, too, may pass from this world without seeing our dreams realized but tomorrow's children will march beyond our bones to that promised land. I dream that we will rise up with integrity, with faith, and with the great assurance that what we march toward is worthy and right, and we will not give it up without a fight.
And more than dream, I vow. I vow to carry on. I vow to reignite the flame. And I vow to fan that fire so that not even the mightiest wave can snuff it out, until the whole world burns with the bright light of freedom, of liberty, and of justice for all.
I just shared on FB. As I said there: Wow. My heart is both full for the words you share, and broken for the same.
Keep speaking your truth, your impressive way. Please.
Thank you, Marie. Together we can surely keep the dream alive and thriving!
Marie said what was on my heart as well. Beautifully and powerfully written. Won't it be wonderful when we are able to look back on history and wonder that there ever was such ugliness in the world?
Thank you, Debi. That truly will be a bright and beautiful day!
Khara, this is beautiful, and brave and so so necessary. THANK YOU.
Thank you, De! I certainly hope I'm able, in any small way, to continue to honor the legacy Dr. King left for us all.


text:
Meltdown: Ice Cracks at North Pole
By Sara Goudarzi 20 September 2006
This 29 August 2006 Envisat MERIS image highlights the area North of Svalbard, Norway, where a very low sea ice concentration can be seen. The image width is about 800 km.
(Image: © European Space Agency)
Satellite images of the Arctic show large openings in the perennial ice cover, yet another consequence of greenhouse warming, scientists announced this week.
The Arctic's thick perennial sea ice typically survives the warmth of the summer and lasts through the year. But satellite images taken in late August show that up to 10 percent of the perennial sea ice has been fractured by summer storms. The surprising change involves an area larger than the size of the British Isles.
The striking openings in the pack ice were found north of Svalbard, Norway and extend to the Russian Arctic all the way to the North Pole. This condition is likely due to the thinning and extra mobility in the European section of the central Arctic ice pack seen in recent years.
"This situation is unlike anything observed in previous record low ice seasons," said Mark Drinkwater of the European Space Agency's Oceans/Ice Unit. "It is highly imaginable that a ship could have passed from Spitzbergen or Northern Siberia through what is normally pack ice to reach the North Pole without difficulty."
The minimum ice extent—the lowest amount of ice recorded in the area annually—has shrunk from 3 million square miles in the early 1980's to less than 2 million square miles in 2005. A recent study showed that between 2004 and 2005, the ice shrunk by 14 percent, a decrease in area the size of Texas.
"If this anomaly trend continues, the North-East Passage or 'Northern Sea Route'between Europe and Asia will be open over longer intervals of time, and it is conceivable we might see attempts at sailing around the world directly across the summer Arctic Ocean within the next 10-20 years," Drinkwater said.
Images: Earth through the Seasons
Snow Melting Earlier In Eastern North America
Global Warming or Just Hot Air? A Dozen Different Views
Greenland Dumps Ice into Sea at Faster Pace
Glaciers Disappear in Before & After Photos
What makes Earth habitable? This LiveScience original video explores the science of global warming and explains how, for now, conditions here are just right.


text:
Game Changer: The 69m lifestyle launch pad from Damen
1 December 2017By Chris Jefferies
"This is really a floating heliport, that's what it is." Speaking to Rose Damen, commercial director of Damen, it's clear that one feature stands out above all others on board 69.15 metre Game Changer, the latest member of the Dutch yard's Yacht Support collection.
She is not just the largest of the fleet to date; she is the only one with an explosion-proof hangar under her fully certified, SOLAS approved, five tonne helipad. This cavernous space can swallow up a Bell 429, Leonardo AW109 Grand New or an Airbus H155. Whichever model is carried, there is enough fuel on board (10,000 litres) to keep the chopper topped up all season. "You can't really compare it to a yacht from a helicopter operations perspective," Damen adds. "It's a different story."
But Game Changer is not a one-trick pony. Described by her builders as a crew paradise, this superyacht support vessel was designed to lure the best staff, with enviable accommodation and service facilities: she sleeps 21 crew members in 11 cabins, and boasts a restaurant-grade galley, SOLAS-approved hospital and even an on-board gym. The wealth of space allows the crew to work on rotation and properly relax when they are off duty and not worry about disturbing guests — because the guests are on another boat.
Kenan Seginer, former captain of Garçon, a 67 metre version of Damen's Yacht Support vessel, is in no doubt as to the benefits of running such a boat alongside a yacht. It's not just about carrying a larger helicopter or more crew, he argues, but thinking outside the box in terms of what the superyacht experience can be.
"You can play around with it — you can have your support yacht sitting off Pampelonne beach and your mother yacht sitting in Monaco. All you have to do is transfer guests by helicopter — it takes 15 minutes and job done. The spontaneity is worth it."
But with a range of 4,500 nautical miles at 16 knots and some seriously rugged naval architecture, Game Changer is by no means tied to the Med. The design is unashamedly utilitarian, with purposeful lines that draw on the yard's commercial heritage. "It's all about the axe bow," explains Wouter Kleijpoel, Yacht Support design manager at Damen. "It literally slices through the waves, like an axe."
The yard reasons that a 75 metre mothership served by a 69 metre support vessel will have the combined capabilities of a 97 metre superyacht, but at only 70 per cent of the cost. This is evident in her toy and tender storage. Game Changer's 250 square metre amidships deck can carry 350 tonnes of cargo, loaded via a seriously chunky davit crane that can lift 11.45 tonnes, slew around 360 degrees and reach up to 16 metres. And there is a secondary crane too, dedicated to launching the crew tender.
For her debut voyage across the North Sea, Damen loaded up a Wajer 38 dayboat, a 10.5 metre military-style RIB and a U-Boat Worx personal submarine. Inside, her fully stocked dive centre has plenty of room for a decompression chamber, should an owner want to add one, while the 48 square metre workshop allows Jet Skis and smaller tenders to be serviced in a weatherproof, air-conditioned environment.
Even with all this kit on board, Game Changer's quadruple MTU 16V 4000 M63L diesel engine set-up generates a grand total of 12,000hp and delivers a top speed of 20 knots.
Game Changer is the ninth Yacht Support vessel to launch, closely followed by the 55.3 metre New Frontiers, which was splashed in July. With an 11th vessel already under construction, this range of floating launch pads seems to be taking off as fast as its choppers.
First published in the November 2017 edition of Boat International.
SUPERYACHT DIRECTORY
Damen 72 m | 2017
Shadow Boats: Standout Superyacht Support Vessels
Damen yacht support vessel Game Changer sold
Video: First look inside 55m Damen yacht support vessel New Frontiers
Magellano 25 Metri: On board the new Azimut superyacht
Standout New Superyacht Deliveries
DreAMBoat: On board Oceanco's daring 90 metre speculative build
Presidential yachts: Inside the superyachts owned by world leaders
Inside INEOS Team UK's radically redesigned America's Cup race boat Britannia II
Spirit: On board the refitted 55 metre Amels superyacht


"I don't think anybody can make any sense out of it," he said.
I saw this 30 minutes ago on another forum.
Yeah that girl is obviously out of her mind. The boyfriend is either crazy as well or he's just incredibly irresponsible.
welll, unfortunately there are people like that girl ... but what's wrong with her boyfriend? I also think he's insane.
... she was stuck to a toilet..
That's pretty... uuugh... Crazy. Two years... ?


text:
Home English Everything you should know about duvet covers
Everything you should know about duvet covers
It's easy to get used to, but there's nothing like crawling into a freshly made bed. The smell of clean sheets is lovely—and so is the feeling! But while we love the feel of a clean bed, what we don't always love is all the work that goes into making it. That's why we're sharing our best tips for how to make your bed quickly and efficiently. But we all know how important it is to get into a clean one every morning!
https://www.readbakery.com
Bed sheets make for a better night's sleep, but changing them can be annoying. Here are some hacks to simplify the process!
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New Jersey Administrative Code for special education (N.J.A.C. 6A:14) and the federal Individuals with Disabilities Education Act of 2004 (IDEA 2004) are laws that ensure children with disabilities a free, appropriate public education in the least restrictive environment. An important part of these laws provides parents with the right to participate in their children's education. You and representatives of your school district are team members who are responsible for developing an appropriate educational program for your child. This document will describe the state and federal laws affecting the provision of special education to help you understand your rights in the special education process. With this knowledge, you will be prepared to take an active role in your child's education. This document has been developed for you by the Department of Education, Office of Special Education Programs, in an effort to provide the most comprehensive and up-to-date information. The document is periodically revised to reflect changes in the law, provide additional information that would be of use to you, and to provide the information in a more clear and concise manner. If you need additional help in understanding your rights, contact information for the Statewide Parent Advocacy Network (SPAN), Disability Rights New Jersey (DRNJ), the County Offices of the New Jersey Department of Education and your local school district is listed on page 42.
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text:
Of Course Jill Biden Has Her Own 'Hail to the Chief' Fanfare
The following story is brought to you courtesy of Red State. Click the link to visit their page and see more stories.
I know: try to control your shock and amazement.
I mean, who'd a thunk "Dr." Jill Biden would have her very own "walk-up" fanfare — her own "Hail to the Chiefette" — to be played when a woman who was elected to nothing and has zero executive power about anything "walks up" to super-important stuff. Come on, admit it. Gives you goosebumps, huh? [ROFL emoji]
The United States Marine Corps Band was instructed last fall to come up with an entrance theme for the pretend doctor, a source told the Washington Examiner. And just like that, the band now has in its repertoire an original composition titled "Fanfare for the First Lady."
The fanfare, noted the Examiner, "is to be performed and repeated at official White House functions, from her first appearance until she is ready to speak."
Imagine, for a nanosecond, the histrionic mass meltdown within the Democrat Party, the sock-puppet Democrat-propaganda media, and among all liberal loons across America if we were talking about Melania Trump, here, versus Jill Biden.
Did I mention that no other First Lady has ever had a "walk-up" song?
But here's the thing. Jill Biden isn't just one of your run-of-the-mill First Ladies, mind you — like Melania.
Oh hell, no. For example, here's Jill aboard Air Force One on the way to Europe in June, "prepping" for the G7 Summit. Very impressive, given that she had zero to do with the summit. And note the presidential-looking jacket, purposely draped over the back of her chair, solely for "impressive" photo-op purposes.
The band was reportedly "rushed" to complete the fanfare, which technically wasn't created for Mrs. Biden; it's a finalized version of a piece of music that was already nearly completed when the topic was first discussed with the White House.
Though it's not unusual for the group's arrangers to be asked to compose music at a moment's notice, a source told the Washington Examiner, it is unusual for the first lady to have her own entrance theme.
The cherry on top giving the first lady the "Hail to the Chief" treatment, the source said, is this: "The music is just awful."
"The song is terrible," the source said, adding it's ironic a "completely bogus premise" should result in such an "awful" final product.
"Fanfare for the First Lady" has reportedly created both "amusement and confusion" within the band, with some band members saying that in the many years they've played in the group, this is the first time the band has had to provide the First Lady an exclusive entrance theme.
Someone in the White House apparently "had the bright idea, 'Oh, tell the band that we want music for Jill,'" a source said. "The band had to provide music."
So, here's the thing. Given Jill Biden's love of (choose one or more of the following) attention, power, respect, titles, her husband being president, having her very own entrance fanfare should surprise no one.
After all, this is a woman who should have strongly opposed the nomination and election of an addled man, clearly in mental decline, whom I assume she loves, simply and singularly because she selfishly and desperately wanted to become First Lady.
Jil Biden wanted the attention; the accolades; the (faux) sense of power and everything that comes with it. For that, she deserves zero respect — and hardly her own fanfare.
Nonetheless, America, I now present "Fanfare for the First Lady" — and you-know-who.