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History of wireless telegraphy and broadcasting in Australia/Topical/Clubs/Telegraph Electrical Society

Telegraph Electrical Society
Frank Randell Bradley was an early wireless experimenter, holding callsign 3ZK Sandringham (later A3ZK, OA3ZK, VK3ZK) from as early as 1923, through to 1930. The Wireless Regulations were altered in 1924, requiring examinations in telegraphy skills and wireless reception and transmission theory. While his position within the Postmaster-General's Department would likely have permitted an exemption, he took the examination and was awarded Amateur Operator's Proficiency Certificate No 2, being the first in Victoria. He relocated to Sydney for his employment from 1931 and in accordance with the regulations of the day, was allocated callsign 2JB (VK2JB). He does not seem to have been prominent in amateur radio circles during the 1920s and 1930s, but this requires further research. Amateur radio operations were closed down in 1939 with the commencement of hostilities for the Second World War. At the conclusion of the war, after a period, amateur radio again commenced, however Bradley did not reapply for a licence.

Bradley was born in South Australia and was educated there at the School of Mines and the University of Adelaide. He excelled academically with strong results in all subjects. He commenced with the Postmaster-General's Department in the usual way as a telegraph messenger. He transferred to Melbourne about 1920 for promotion within the PMGD, concluding there in 1930 as Superintendent of Telegraphs. Another transfer to Sydney occurred in 1931 for a further promotion within the PMGD. In 1946 he transferred to Brisbane as Deputy Director of Posts and Telegraphs, Queensland, a position formerly held by James Joseph Malone.

A comprehensive history of Telegraph Electrical Society has not yet been prepared, however the following resources have been assembled in preparation:

 * Transcriptions and Notes - Telegraph Electrical Society - More than 20 transcriptions and notes

 * Photos, QSL cards and other graphics - Telegraph Electrical Society - Nothing uploaded as yet

 * B. McMahon's 1939 article in the Telecommunications Journal of Australia on the Early History of the Telegraph Electrical Society, Melbourne - Complete, thanks to scans of the Journal made available on Rick Coxhill's excellent website recording the History of the Telstra Research Laboratory

 * Work-in-progress of Wikipedia Article on Telegraph Electrical Society - Not yet started

Prominent members and office holders:
 * William Philip Bechervaise (early telephone experimenter)
 * Peter Robert Challen (early telephone experimenter)
 * Louis Septimus Daniel (early experimenter in "Etheric Force")
 * Henry Walter Jenvey (early wireless experimenter)
 * Duncan James Macfarlane McGauran (developer if not inventor of the quadraplex telegraphy system, sadly passed in his prime)
 * George Smibert (later Chief Electrician)

In the National Library of Australia's Trove website, more than 200 articles (Newspapers & Gazettes) have been tagged as "Telegraph Electrical Society Vic" (search publictag:Telegraph Electrical Society Vic)

A search in Trove on "Telegraph Electrical Society" identifies more than 300 articles, the majority of which refer to the Telegraph Electrical Society Vic, those tagged to date are a quick review to identify the most important for this Wikibook. Articles transcribed for Notes are tagged: "Wikibooks - TESV". Articles reviewed and considered either duplicates of other articles or not of sufficient importance for inclusion are tagged: "Wikibooks - TESV Not"


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History of wireless telegraphy and broadcasting in Australia/Topical/Clubs/Telegraph Electrical Society/Early History

THE EARLY HISTORY OF THE TELEGRAPH ELECTRICAL SOCIETY, MELBOURNE

by B. McMahon, D.P.A. A.M.I E. (Aust)

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In the June, 1938, issue of the "Telecommunication Journal of Australia," Mr. E. J. Credlin, in writing of the inauguration of the Postal Electrical Society in 1908, referred to the formation of the first Electrical Society in Victoria in 1874. Through the courtesy of Mr. F. R. Bradley, Superintendent of Mails, Sydney, copies of the transactions of this Society have been made available. The transactions were first published in a bound volume issued in 1875, from which it is learnt that the first Ordinary General Meeting was held on Wednesday, 12th August, 1874. On one of the introductory pages it is advertised that the Society was established "for the promotion of the knowledge of electricity, especially as connected with telegraphy." The Society arranged to meet for the transaction of business at the Melbourne Athenaeum on the second and fourth Wednesdays of each month at 8 p.m. The first Committee of Management comprised Mr. G. Smibert, Mr. D. Mickle, Mr. D. J. McGauran and Mr. H. W. Jenvey. The Honorary Secretary and Treasurer was Mr. L. S. Daniel. Throughout the first volume of transactions, Messrs. McGauran and Daniel were frequent contributors, and apparently their work and enthusiasm contributed greatly to the successful establishment of the Society. The subscription was £1 per annum for town members and 10/- per annum for corresponding (or country) members. In the early volume no mention is made of a President, and the transactions show that there was a different Chairman at each meeting, Mr. D. J. McGauran occupying the chair at the first meeting, followed by Mr. C. W. Miller, Mr. D. Mickle and Mr. George Smibert. There were 48 members and 61 corresponding members, and at the inception of the Society membership was restricted "for the present" to officers of the Post and Telegraph Department. On September 9th, 1874, however, it was resolved "that any gentleman intimately connected with the practice of telegraphy in this or the neighbouring colonies shall be eligible for membership of this Society." Apparently no provision was made for female, or perhaps in the spirit of the age I should say lady members, for Rule No. 12 provided eligibility for membership for no others than "any gentleman intimately connected with the practice of telegraphy . . . . " We can admire the broad outlook of the founders of this Society, who so soon after its inception made membership available to telegraph workers in the neighbouring colonies, a quarter of a century before Australia became a Federation. In 1875 the telegraphic art was more or less a mystery to the general public, if not to many members of the Department, and in this respect it is interesting to read that a short elementary lecture on electric telegraphy was given by Mr. L. S. Daniel as an introduction to the Exhibition of the Electric Telegraph at a public entertainment which was given by the members of the Society at the Melbourne Athenaeum on Monday, 1st February, 1875. The entertainment, which was presided over by Mr. Turner, the then Deputy Postmaster-General of Victoria, "was very successful, and the Melbourne Press was unanimous in pronouncing it one of the most interesting lectures ever given in the city." In recent times there has been much discussion on the use of proper functional designations for professional and technical occupations, and some of the words around which the discussion has turned are "Mechanic," "Electrician" and "Engineer." Those who now lean to the word "Electrician" are perhaps unconsciously following a precedent established as far back as 1874, when Mr. H. W. Jenvey, in his paper on "Electrical Resistance," wrote "and here I will introduce a fundamental law of electrical measurement named after an Electrician who put it into form. It is, "That the quantity of electricity passing a given point in a circuit in a given time is equal to the electromotive force, or original and natural power of the battery, divided by the resistance of the circuit." This is called Ohms Law, and Mr. Culley, the Electrician, calls it "the basis of all the mathematical laws of electric currents" — a very important definition." That these Electricians of the past were no less human than the Mechanics, Linemen, Electricians and Engineers of today may be gathered from the observations of Mr. L. S. Daniel at the first Ordinary General Meeting of the Society. Mr. Daniel, in submitting that the object of members was to gain knowledge, which was power, put it that "If our value be increased, we may naturally expect a tangible recognition of this improvement." He is rather diffident in mentioning this aspect, and confesses that he "would never have thought of putting the matter in such plain language as he finds it in the Journal of the Telegraph Engineers' Society of London, where he came across the following passage in a lecture, on the Advantages of Scientific Education, delivered by Mr. W. H. Preece, C.E." Mr. Preece, afterwards Sir William Preece, Chief Engineer of the British Post Office, said, "There is no doubt that a knowledge of the technical details of telegraphy will eventually lead to an increase of the emoluments of those who are now engaged in the Department." The Society continued to prosper in its first

P.167
year, and we find that, by July, 1875, the membership had increased to 49, with 78 corresponding members. Though Rule No. 12 making "any gentleman" eligible for membership apparently remained unaltered, we find in the Progress Report for the quarter ending the 30th April, 1875, that the Society had a number of lady members, donations towards the printing fund of the Society having been received from "the following members:— Miss F. A. Dobson, Telegraph Office, Dandenong, 10/-; Mrs. S. E. Kinahan, of Terang, 10/-; Miss E. Allison, of Sorrento, 5/-." The report states that, "These donations are the more gratifying that they have been quite unsolicited." For the information of its members, the Society published in its transactions a reference to "telegraphing the St. Leger, 1874." Over the four days' race meeting the total number of messages transmitted "reached the astounding figure of 16,500." On the same page a reference is made to working speeds of morse instruments. From New York came two instances of fast transmission of ordinary messages, viz., 330 messages in 6 hours, 30 minutes, 50.7 per hour, and 136 messages in 2 hours, 68 per hour. It is then recorded that, on the occasion of the last Melbourne Cup race (1874) 216 messages were sent from the racecourse to Melbourne, on one of the wires, in 1 hour and 58 minutes, being at the rate of 109.8 per hour, while at the Cup of the previous year the rate was 124.5 per hour. It is explained that, on account of the frequent occurrence of the same names, abbreviations could be used to a great extent, and it is then added that, "As a matter of swift penmanship on the part of the receiving operator, these performances could not easily be surpassed." It is clear that our pioneer members did not intend to be outdone by any reports from America. Even in the first year of its life the Society did not lack recognition overseas, for it is reported that Mr. H. W. Jenvey's paper on "The Adjustment of the Morse Instrument," which was read before the Society in October, 1874, was published in the London Telegraphic Journal of July 1st, 1875. Reading on through the transactions, we are brought nearer to the present day by seeing a name at present well known in telegraph and telephone engineering circles in Victoria, for on the 22nd September, 1875, "Mr. H. Quarry described and illustrated Wheatstone's Alphabetical Instrument by taking to pieces and showing the construction and mechanism of its different parts." In the same issue we find the Society attempting to lighten the tedium associated with reading heavy technical matter by including a paragraph culled from the "Electrical News," which read: "The practice of hanging linen to dry on the telegraph wires has, according to the Pall Mall Gazette, lately become general in Armenia, and revealed the hitherto unknown fact that the peasantry of that country are in the habit, occasionally, of washing their clothes . . . . " The march of time in the affairs of nations is brought vividly before us in reading the report of the International Telegraphic Conference which was held at St. Petersburg, We no longer hear this city so named, but surely all engaged in the business of telecommunication will derive some satisfaction from the thought that, for three-quarters of a century, representatives of all nations have gathered together for a common purpose and discussed amicably and with such wonderful results the problems which have arisen in telecommunication affairs throughout the world. Another matter of interest in the same issue is an extract from the "Queensland Times" of March, 1875. The editor of this paper often wondered how it was that a proper word had not been invented to express the name of a message sent by the submarine wire, without pedantry. He affirmed that the word "Cablegram" was simply execrable, both in sound and linguistic propriety. He then suggests, "Why not use the euphonius word "Calogram," which is from the Greek word "Calos" — a cable? . . . " and to think that, in 1939, we are still using "Cablegram." In the transactions for the year ending July 31st, 1875, is published an extract from the "Sydney Morning Herald" of January 11th regarding the submarine cable to connect the Colony of New South Wales with New Zealand. "The Herald" article reported that the first portion of the cable arrived in the steamship "Edinburgh," which was the first cable ship that had then visited this part of the world. On this account the arrival of the ship created great interest in Sydney. She carried a 240-mile length of the New Zealand cable, the remainder being on board the "Hibernia," which was expected in Sydney in another few weeks. It was reported also that the "Edinburgh" on the same trip brought from England a short cable "about 35 miles in length, which she laid near Adelaide, across what is known as the Back Passage, to connect the telegraph line between Western and South Australia." South Australian members might know what has become of this cable. That the same friendly spirit which now characterises the association of technical officers of the telecommunication services was in existence to just the same extent in the early days of telegraph societies may be gleaned from a report of a gathering held on Tuesday evening, 7th March, 1875, at 9 p.m. About 60 officers of the Department assembled at Clement's Cafe (Does any member remember it?) to make a presentation of a silver tea and coffee service to Mr. D. J. McGauran. The report relates that, "It

P.168
having transpired early in March that the New South Wales Government had secured the services of Mr. D. J. McGauran, Operator, of the Melbourne Office, and a member of the Committee of Management of this Society, it was immediately and unanimously resolved not to allow him to leave the Department in which he had for so many years been so deservedly popular, without some souvenir from his fellow-telegraphists." The Chairman was Mr. T. R. James, who referred to his amusement at receiving a letter from a country member complaining that "New South Wales was gobbling up all the plums." Mr. James added that "the sister Colony had now gobbled up our choicest plum. (Hear, hear.)" A separate paragraph in the report relates that "Champagne and other refreshments being now introduced, the Chairman called upon the meeting to drink Mr. McGauran's health, which was done amid great applause." It is not known what effect the refreshments had on the gathering, but it is naively reported later that, "The official portion of the proceedings having now terminated, the remainder of the evening was spent in a most pleasant manner." (The black type is ours.) The report concludes, "Some astonishment was subsequently excited at the Hobson's Bay Railway Terminus by the larger portion of the meeting accompanying Mr. McGauran to the St. Kilda 11 p.m. train, and saluting him as the train moved off, with hearty cheers." It may be a fair inference that the last train in those days departed at 11 p.m. Those members who are particularly concerned with the telephone side of telecommunication will be interested in a report headed "Novel Telegraphy in Canada." It includes an extract from the "Brantford Expositor," which relates that a number of gentlemen interested in scientific matters recently assembled at the office of the Dominion Telegraph Company to witness some very wonderful experiments on an apparatus invented by Mr. A. Graham Bell, son of Professor A. M. Bell, of Tutelan Heights. "This gentleman claims to be able to transmit musical sounds over a telegraph wire." Members are aware of the rapid progress made in the years immediately following, and the photograph published in the June, 1938, issue of the welcome to Dr. Graham Bell at Melbourne Central Exchange on the 17th August, 1910, will now be of special interest. From 1874 to 1876 the proceedings of the Telegraph Electrical Society were published as "transactions." In the next issue covering the period March to July inclusive, 1877, the title "Journal" is used, and as the only other copy of the proceedings which is available is for the January to December period of 1881, when the term "Journal" is still used, it may be assumed that the "transactions" permanently gave way to the "Journal of the Telegraph Electrical Society, Melbourne." In the 1877 Journal further reference is made to Professor Graham Bell's telephone. "The most wonderful of these telephones is that invented by Professor Graham Bell. By means of his telephone the human voice (or any other sound) is carried by magnetic currents along a telegraphic wire and reproduced at the stations on the lines . . . . It has been seen by Sir William Thomson and pronounced by him to be "the greatest by far of all the marvels of the Electric Telegraph," and the Telegraphic Journal, London, states that so many proofs have been given of the authenticity of the invention that its reality can no longer be a matter for doubt." That this confidence in the report was not shared by the editors of the Melbourne Journal may be gathered from the comment just a little later in the report. It reads: "What we are called upon to believe about this invention is of such a nature as to make a personal inspection of it almost essential, in order to destroy all doubt of its reality." After a reference to the method of working the report goes on: "This is hard enough to believe, but when we have to add to this that the vibrations are produced in the first instance by the human voice, and that the vibrations produced on the plate at the other end of the line are made to reproduce the articulate sounds of the human voice, surely it is no wonder that there are to be found persons of no small scientific attainments who, in the absence of ocular demonstration, have declared the so-called invention to be 'a physical impossibility.' " (Reference July, 1877.) However, the editors were not without a broad outlook on general matters, and during 1875 an article was published on the "Typewriter." It said that, although this clever invention was not directly connected with electricity nor with telegraphy, the art of fast writing was so important a feature of the latter that it was considered the accompanying article (from "The Times" of April 25th) would not be out of place in the Journal. One of these instruments was reported to be in the possession of the New South Wales Telegraph Department, and the Committee of Management of the Victorian Society indicated that it would be glad to have a practical opinion of the estimation in which it was held there. In "The Times" article the reporter states that, "The typewriter more nearly resembles in outward appearance a sewing machine than anything else. . . . The uses of this ingenious contrivance are so obvious and so numerous that we may content ourselves by observing that the only work to which it cannot be applied is that of bookkeeping or writing in books." In the Journal for the period ending July, 1877, is published an account of the first steps in electric telegraphy in England, being an ex-

P.169
tract from the inaugural address by Mr. C. V. Walker, F.R.S., on the 12th January, 1876, on being elected President of the Society of Telegraph Engineers. Mr. Walker referred to the deep debt of gratitude owed to electric telegraphs by the Railways, but he remarked that the debt was not all on one side. He quoted remarks published as early as March, 1850, that "The electric telegraph is greatly indebted to the Railways, if not for its existence, at least for the friendly hand they have held out to it, and indeed for the protecting care with which they have guarded it . . . . This little line of telegraph (Great Western Railway) was then one of the sights of London. Well do I remember in 1845 paying my shilling to see it. It was made known by handbills to passers-by." Present members will be interested in the reprint of the handbill published on this page. It is of interest to note the comparatively wide range of technical discussion and study covered in the early years of the Society, despite the limited membership and the restricted facilities. Following are titles of some of the lectures delivered between 1874 and 1877, following the inaugural lecture by Mr. L. S. Daniel on "The objects, use and working of the Telegraph Electrical Society":— By Mr. Geo. Smibert: Electricity; Origin of the Voltaic Current; Magnetism and Electro-Magnetism; Arrangement of Circuits and Commutators in the Chief E.T.O., Melbourne. By Mr. D. J. McGauran:— Duplex Telegraphy (with demonstration); On the Transmission of two messages in the same direction at the same time on one wire; An auto-translator for closed circuits. By Mr. H. W. Jenvey:— Electrical Resistance; The Adjustment of Morse Instruments. By Mr. H. Quarry:— Wheatstone's Alphabetical Instrument. By Mr. S. Deverell:— Sea-water Battery. By Mr. P. R. Challen:— Statical Electricity and a brief discussion of the means of producing it. Mr. L. S. Daniel, in addition to lecturing on "The Morse Instrument," read an extract entitled "Aldini's Bovine Battery" dealing with electricity in the bodies of human and other animals. Mindful of the interests of its members, the Society in 1875 set out to provide a course of instruction, and there are printed four papers on "Galvanic Batteries" read by Mr. D. J. McGauran, "being part of the course of instruction which it has been determined to pursue." During the visit of the cable ship "Duke of Edinburgh" the opportunity was taken to invite the ship's Chief Electrician to read a paper on "Interference Between Lines." The Journal for March to July, 1877, was devoted largely to "giving members some account of the instruments at present exciting much interest in Telegraphic circles, and which, from their power of conveying sound, are called telephones." In addition to reports of Bell's lectures and demonstrations in U.S.A., reference was made to Reiss' telephone and Cray's instrument. The trend towards telephony continued, for the 1881 Journal opened with "Modern Forms of the Telephone," by James Doyle, M.S.T.E., though the remainder of this issue dealt with telegraphy, and in September, 1881, we, see the first reference to quadruplex in a "Note on the working of the Quadruplex between Sydney and Melbourne," by Mr. D. J. McGauran. The last reference in the 1881 volume is a re-

P.170
view of the Report of the Adelaide Observatory for 1879, presented to the Society by C. Todd, Esq., C.M.G. Mr. Todd, who was then P.M.G. and Superintendent of Telegraphs in South Australia, later became Sir Charles Todd, a name prominently associated with the building of the overland telegraph line between Adelaide and Darwin. This 1881 volume is the last printed record we possess of the proceedings of the Telegraph Electrical Society between the time of its inception in 1874 and its revival as the Postal Electrical Society in 1908. The enthusiasm of its founders and early members has left us this record of their splendid work for the first eight years.

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license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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User:Unpoichiche/sandbox/Approaches to Knowledge/2020-21/Seminar group 6/Jeanne Brocart

1. My Chinese is better than my Spanish 2. I haven’t watched game of thrones 3. UCL actually wasn’t my first choice


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Serbian/Main Contents/Level 2

Serbian Grammar Lesson 1 - /present tense/

title: Serbian/Main Contents/Level 2


text: User talk:98.153.80.138

title: User talk:98.153.80.138


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User:JarrodPhillips11

Jarrod Phillips

title: User:JarrodPhillips11


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Exercise as it relates to Disease/The effects of exercise on low-density lipoprotein (LDL) and cardiovascular disease

This article critiques and analyses the paper: "Exercise and Cardiovascular Disease: A New Perspective"

What is the background to this research?
Cardiovascular Disease is one of the largest causes of disability and premature death around the world, where the underlying cause comes from atherosclerosis (a build up of fats and cholesterol on the walls of the arteries that restricts blood flow).

Low-Density Lipoproteins are the physical form in which lipids are transported around the body via the bloodstream, and it is believed that they are also a key event in atherogenesis (the formation of fatty deposits in the arteries). Exercise puts the body through an oxidative state of stress which is an important deterrent for any development of cardiovascular disease, although LDL production is enhanced under this stress, therefore, creating a paradox.

Further research must be done in order to fully understand the events that occur within the body in relation to LDL production when it undergoes oxidative stress during exercise. This will allow researchers to gain additional information on how other health professionals should prescribe exercise as an intervention to decrease the risk of developing cardiovascular disease.

Where is the research from?
The research paper that I have chosen was published in the Journal of the American Heart Association, which is acknowledged as one of the most reliable medical journals for Cardiovascular and Cerebrovascular Disease studies.

The lead author of this paper, Robin Shern-Brewer, has acquired a PhD and is a licensed and registered dietitian who has been involved in several studies around exercise and how it impacts health and its relationship with cardiovascular disease.

Shern-Brewer worked on this study with four other researchers who each have a varied background in health science studies and past research. This worked to their advantage for creating a method that is valid, reliable and successful in what they were trying to measure in such a complicated and invasive study. There is no reason to suggest or believe that any bias has been incorporated into the study.

What kind of research was this?
This research can be considered as both basic research and applied research because of what the study tried to achieve in its results. In basic research, it is about investigating the occurrence of events, processes or phenomenon based off basic principles and reasoning, while applied research focuses on what changes would need to be made and how to correct any issues that may seem problematic to the study.

Both types of research provide valuable insights into any problems that may arise and can provide conclusions and logical explanations for any findings that relate directly to the study. Although it is important to remember that human error can occur at any stage, and an unknown bias from any of the researchers can also affect the conclusions made at the end of the study.

What did the research involve?
Study 1 consisted of 8 Exercisers (6 Males, 2 Females) and 9 Sedentary Controls (1 Male, 8 Females) and was conducted to examine the ability of LDL to oxidise between exercisers versus sedentary subjects. Oxidation levels during exercise were measured by the use of a 2.5 μmol/L copper system, and other measures such as biochemical markers, plasma lipid levels, plasma and LDL vitamin E levels, plasma TBARS, and plasma and LDL electrophoretic mobility were recorded.

Study 2 consisted of 30 Exercisers (15 Females, 15 Males) and 33 Sedentary Controls (21 Females, 12 Males) and was conducted to evaluate any confounders in Study 1. Oxidation levels during exercise were measured by the use of a 5 μmol/L copper oxidation system, and all the measures described in Study 1 were also used for Study 2, along with a few additional measurements. These include: LDL fatty acid composition (linoleic, linolenic, and arachidonic), and MPO protein levels.

The exercisers in the Study 1 group had been in regular bouts of training for less time (<1 year) than compared to exercisers in the Study 2 group (>2 years).

Exercise testing measured Vo2 Peak on a Marquette treadmill where the intensity of the exercise was monitored every minute by heart rate monitors and self-reported ratings of perceived exertion. The test was to be ceased immediately if the subject asked to stop, if they reached 95% of their age-predicted maximal heart rate (APMHR), or if they reached a respiratory exchange ratio ≥1.1. Blood samples of 15mL were taken from the subjects' forearm vein after an overnight fast but immediately before and after each exercise intervention on the treadmill.

Lipid analysis, isolation, and oxidation of LDL were measured using a Cholestech L*D*X analyser, where TBARS were also measured within the plasma. The fatty acid determinations were analysed by a high-performance liquid chromatography system called Rainin and monitored at 192 nm on a UV detector. An Enzyme-Linked Immunosorbent Assays (ELISA) laboratory technique was used to measure the plasma MPO levels.

What were the basic results?

 * In the findings of Study 1, it is suggested that the exercisers had increased amounts of preformed lipid peroxides, which could potentially increase their susceptibility to LDL oxidation. In Study 2, the findings suggest that chronic exercisers are always going through increased levels of oxidative stress, based off the higher level of MPO protein found in their plasma in comparison to the sedentary subjects.

What conclusions can we take from this research?
Men that engage in regular "chronic" exercise over months at a time can reap the benefits of decreasing their susceptibility of the oxidation of LDL throughout the body. In saying this, regular aerobic stress can also create a higher oxidative environment throughout the body when done over a smaller time span, which would therefore increase LDL oxidation susceptibility. In women, when aerobic exercise creates an oxidative stress in the body, there is no evidence to suggest any effects on the oxidizability of LDL.

Therefore, the paradox addressed in the study has been supported through this research.

Practical advice?
A number of factors such as dietary, exercise, and lifestyle habits all play a part in potential health implications associated with obesity, cardiovascular disease, and coronary heart disease. Clinical practice guidelines about diet and exercise have been implemented in order to decrease the risk of developing the mentioned risks, and these include: consuming 2 or more servings of fruit, 3 or more servings of vegetables, in conjunction with 30 minutes of physical activity or more each day.

Although exercise has been renowned worldwide as the leading recommendation for decreasing the risk of cardiovascular disease, it also increases total oxygen consumption and enhances the depletion of plasma antioxidants, due to the oxidative environment created by exercise.

To fully understand this paradox, more intensive and extensive research must be carried out in order to gain further knowledge about the oxidative environment in the body and what effects (both positive and negative) it may have on the body in short and long term.

Further information/resources
Below are a few extra resources for additional learning if anything in this article was of interest to you:
 * Heart Foundation
 * American Heart Association
 * Heart Research Institute
 * Heart Foundation
 * WebMD: LDL Cholesterol


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User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 5/Geoffrey Boycott

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User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 5/Ivory Allen

 * 1) Terrified of birds- pigeons, ducks, swans, etc.
 * 2) Coached by a Zimbabwean olympic swimmer when younger
 * 3) Has over 2000 followers on TikTok


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User:WoodzyMoodzy/sandbox/Approaches to Knowledge/2020-21/Seminar group 5/WoodzyMoodzy

1. I've watched every movie in the MCU 2. I did ballet for 12 years 3. My wallet got stolen while on a trip to Barcelona


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User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 5/Camille Drevet

1. I got lost at night in the mountain in a ski resort and was forced to sleep in a cable car.

2. Once, I dressed up like a grape and danced in front of 500 people.

3. I can juggle with a gym ball on my feet for hours.


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User:Poccy3/sandbox/Approaches to Knowledge/2020-21/Seminar group 5/Naoumi Lugtu

 * 1) I have lived in both France and Germany.
 * 2) My favorite music genre is techno music.
 * 3) I have had the chance to visit every continent.


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User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 5/Lucky Lilac Lion

 * 1) When I first moved to London 4 years ago, I bought a membership for the London Zoo and would regularly visit it to check up on the animals.
 * 2) I lived in a French-speaking part of Belgium for 6 years, but only started learning French after I moved to the UK.
 * 3) Years ago, my parents and I went to watch Pixar’s ‘Up’ in the cinema and we were the only ones in the whole screening room.


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User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 5/Naoumi Lugtu

1) I got lost and walked 30,000 steps in one day

2) I have eaten fruit which came from an endangered tree species

3) I have tried to swim the English Channel


text:
User:Basc.blue/sandbox

1. I have dyed my hair 6 colours in the past, including the blue that it is now

2. I'm from Wales and I have lived there for my entire life

3. I have an irrational phobia of crumbs and my friends always clean tables for me before I sit down in a restaurant

title: User:Basc.blue/sandbox


text:
User:Poccy3/sandbox/Approaches to Knowledge/2020-21/Seminar group 5/Niklas Jütting

 * 1) I have lived in both France and Germany.
 * 2) My favorite music genre is techno music.
 * 3) I have had the chance to visit every continent.


text:
User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 5/WoodzyMoodzy

1. I am fluent in Korean 2. I did ballet for 12 years 3. My wallet got stolen while on a trip to Barcelona


text:
User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 5/Niklas Jütting

 * 1) I have lived in both France and Germany.
 * 2) My favorite music genre is techno music.
 * 3) I have had the chance to visit every continent.


text:
User:AurelieJane/sandbox/Approaches to Knowledge/2020-21/Seminar group 5/AurelieJane

1. I was not born in a hospital 2. I had braces for 6 years 3. I have been a dancer for 14 years 4. I am the leader of the world's biggest drug cartel


text:
User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 5/Jenna Chan

1. I've watched every movie in the MCU 2. I did ballet for 12 years 3. My wallet got stolen while on a trip to Barcelona


text:
User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 5/BonSchlonzo

1. I completed a cycling tour over the Alps.

2. I have lost my phone 6 times already.

3. I have lived in Iran for 5 Years and only moved to Germany at the age of 6.


text:
User:Dearenemy/sandbox/Approaches to Knowledge/2020-21/Seminar group 6/Wiktoria Magnuszewska

1. I lived in Alps but can't ski

2. I am Polish but don't like vodka

3. I lived in Bulgaria but can't speak Bulgarian


text:
User:Onchesilbeach/sandbox/Approaches to Knowledge/2020-21/Seminar group 6/Sophie Xu-Tang

 * 1) I've lived in London my whole life.
 * 2) I played Benvolio ( a male character!) in our school production of Romeo and Juliet
 * 3) I have a twin sister who is also at UCL.


text:
Talk:A-level Computing 2009/AQA/Problem Solving, Programming, Data Representation and Practical Exercise/Problem Solving/Algorithm design

four consecutive clock pulses


text:
Type-oriented programming/Restricted properties

While subtyping is often ampliative, that is, a subtype contains all the properties of its supertype(s), it’s often useful to remove an inherited property from a subtype. For example, a complex has a real part and an imaginary part. Every real number is also a complex number but its imaginary part is always equal to zero so we don’t want this property to take up space in the instances. However we can’t remove the imaginary part altogether because it might be used by code working with complex numbers. What one can do is assign the property a fixed value:

type Complex { property real Float property imag Float

func _add(x Complex) Complex { return new Complex { real=self.real+x.real, imag=self.imag+x.imag } }

func _mul(x Complex) Complex { return new Complex { real=self.real*x.real-self.imag*x.imag, imag=self.real*x.imag+self.imag*x.real } }

func description String { return self.real.description + "+" + self.imag.description + "i" } }

type Real : Complex { restrict imag Float = 0.0 }

main { var x = new Complex { real=2.0, imag=3.0 } var y = new Real { real=2.0 } return (x*y).description }

Note that the  type now has only one stored property, but the methods in the   type can still be used with the subtype.

NB: The pseudocode can be tried out using the Funcy app, which can be downloaded for free from Apple’s App Store (iOS/macOS), Google Play (Android) or Amazon Appstore. The code to be executed must be placed in a  block.


text:
Type-oriented programming/Self at the type level

Just like the  variable refers contextually to the instance in whose method it’s used, the   type variable contextually refers to the type. Let’s have a look at a simple example:

type A { sfunc create Self { return new Self } }

type B : A {}

main { var obj = $B.create return obj }

The  method’s return type is   so in the example above it refers to the   type because we called the type method using.

Using  gives the type system considerable power since it squares well with type operators, as illustrated by the following example:

type Maybe[T] { property val T

func description String { return self.val.isNil ? "none" : self.val.description }

func map[U](f Func[T,U]) Self[U] { return new Self[U] { val = self.val.isNil ? nil : f(self.val) } } }

main { var x = new Maybe[Int] { val=3 } var y = x.map[Float](\(x Int) Float . x.asFloat) return y.description + " " + y.typeName }

Note that the  method has a type argument and how   is used. In this case  is a contextual type operator.

NB: The pseudocode can be tried out using the Funcy app, which can be downloaded for free from Apple’s App Store (iOS/macOS), Google Play (Android) or Amazon Appstore. The code to be executed must be placed in a  block.


text:
User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 6/Geoffrey Boycott

jlghfjkljm


text:
User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 6/Chelsea Nicole Florea

·        I never had a dental cavity.

·        When I was a child I invented a language I can still speak.

·        I used to tell everyone I was Bill Gate's daughter.


text:
User:Powerofknowledge113

• Catalan was the first language I learnt to read and write in • I can drive a plane • I used to think I was a boy until my hair grew

title: User:Powerofknowledge113


text:
User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 6/Luiza Kohtanena

 * I accidentally "stole" a Latvian politician's cappuccino at a cafe
 * Until the age of 8 I believed that everyone around me was not a real person
 * After the first (and the last) time trying snowboarding, I could not get up from the bed for full 24 hours


text:
User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 6/Yvette Homerlein

 * I had braces for 2 years, had them removed, then had to get them again for another 1.5 years
 * I have extended family in 5 of the 7 continents
 * I've been a dancer for 10 years but my worst injury has only been a sprain


text:
User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 6/Wiktoria Magnuszewska

1. I lived in Alps but can't ski

2. I'm Polish but don't like vodka

3. I lived in Bulgaria but can't speak Bulgarian


text:
User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 6/User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 6/User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 6

·       I never had a dental cavity.

·       When I was a child I invented a language I can still speak.

·       I used to tell everyone I was Bill Gate's daughter.


text:
User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 6/Sophie Xu-Tang

 * 1) I have lived in London my whole life.
 * 2) I played Benvolio (a male character!) in my school's production of Romeo and Juliet.
 * 3) I have a twin sister who is also at UCL.


text:
User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 6/Roxane Martinon

1. I can speak 6 languages (ish) 2. I turn 18 next April 3. I saw Timothee in Paris this summer


text:
User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 6/Apolline Blein

1. I was born in Madrid 2. I have never broken a bone 3. I used to sing in a church choir


text:
User:JREverest/sandbox/Approaches to Knowledge/2020-21/Seminar group 6/Victoire Moisset

1. In highschool I did an internship at the hospital, in the cardiothoracic surgery service. 2. I can shred the electric guitar. 3. When I was a kid, I saw someone having a heart attack.


text:
Category:California

This category includes Books and topics related to the State of California, the 31st state admitted to the United States of America.

title: Category:California


text:
Mixed Real World Math Problems

The following is a set of word problems that are practical problems, meaning a reasonable person can apply them to the real world one way or another. The solutions are also shown beneath each question, so you can check your answer.

Example 1
At the Simpsons’ home in Springfield, Homer Simpson has a generally stable router that works well far more often than not. However, once in a great while, he will be faced with a router-related difficulty or problem that requires him to contact Springfield Tech Support. On average, he will face one problem like this every 18 months. The occurrence of one problem requiring assistance from Springfield Tech Support does not affect the probability of it occurring again; in other words, each Tech Support problem is independent of previous occurrences, and the probability of it happening in any 12-hour interval is constant and memoryless. Find the expected number of times Homer will need to contact Springfield Tech Support in the next 9 years (108 months).

Solution
Since the probability of a Tech Support problem is constant and thus independent of previous occurrences and previous gaps between occurrences, and no time interval is “favored,” this is a Poisson distribution. This information is not needed to answer this question. The expected number of Tech Support problems in 108 months is simply 108 x (1/18) = 6.

Example 2
A follow-up to the previous question. What is the probability that there will be exactly three Tech Support problems in the next three years (36 months)?

Solution
Again, as mentioned before, this is a Poisson distribution. Recall that the formula for the probability of observing an event X times is λX • e-λ / X! where λ is the mean or expected number of occurrences of the event. Since Tech Support problems occur at a monthly probability of 1/18 (about 5.56%), we should expect, on average, two such problems in a period of three years or 36 months, so λ = 2. The probability that there will be three problems that the Simpson family can’t solve without Tech Support is 23 • e-2 / 3! = 8(0.1353)/6 = 0.1804 = 18.04%.

Example 3
John has a Zoom meeting with his teacher Jeff once a week. Under their current weekly schedule, they always meet for two hours on Wednesday nights from 8:00 pm until 10:00 pm. The computer that John usually uses to connect to Zoom is his bedroom computer. Unfortunately, it is prone to system updates, which happen every fifteen days from 7:30 pm until 9:00 pm. John always uses his bedroom computer to attend the weekly Zoom meeting as long as he is able to do so. One Wednesday night, his computer was installing updates, so John was unable to use that computer to attend the meeting and instead had to use a different computer to do so. How many days will pass before this happens again?

Solution
There are seven days in a week, so the Zoom meeting, which takes place on and only on Wednesdays, takes place every seven days. The computer performs a system update once every fifteen days. The length of the compound cycle of the two regular events is the lowest common multiple (LCM) of 7 and 15, which is 105 because LCM(7,15) = 105. Since 7 and 15 are relatively prime, meaning they share no common divisors greater than one, denoted as GCF(7,15) = 1, the two individual cycles are independent. The answer is 105 days.

Example 4
In November 2018, MandJTV published a video to his YouTube channel counting down his top ten least favorite Pokémon. There were 809 Pokémon in existence at that time. Delphox, a Fire/Psychic starter Pokémon introduced in Pokémon X and Y, took the number 5 spot on that list. In other words, Delphox is his fifth least favorite Pokémon, or the fifth Pokémon on his list if he ranks all Pokémon from least favorite to favorite. Had he made a video ranking all 809 Pokémon from favorite to least favorite, Delphox would rank at what number?

 * A) 5
 * B) 600
 * C) 804
 * D) 805
 * E) 809

Solution
This is a hard question. In the unlikely event it is used on an official SAT math section, it would be number 19 or number 20, near the end of the section. Finding the correct answer to this question must be harder than simply subtracting 5 from 809 to get 804. It is a Joe Bloggs answer. Eliminate C. Answer choices A and E simply repeat numbers from the question, so they are also very unlikely to be correct. Eliminate A and E. If you are stuck, you can guess with coin-flip odds between B and D. Of course, if you know how to solve the problem directly, and you are confident you can do it in reasonable time, do so. To find the correct answer, subtract 5 from 809 to get 804, and then add one more: 804 + 1 = 805.

Example 5
Jaycee Dugard was kidnapped from a bus stop on June 10, 1991. For the next 18 years, 2 months, and 16 days, she was held captive in the backyard owned by her two kidnappers and sealed off from the rest of the world. Her captivity ended on August 26, 2009 when she was rescued by police and went home to reunite with her family. Person XYZ was born during Jaycee’s captivity. Person XYZ was old enough to vote by the time Jaycee’s captivity ended. Which of the following could be Person XYZ’s date of birth?

 * A) May 1, 1990
 * B) June 5, 1991
 * C) July 25, 1991
 * D) August 31, 1991
 * E) January 1, 1992

Solution
Jaycee Dugard’s captivity lasted from June 10, 1991 until August 26, 2009. The countless gory details of her captivity are not relevant to answering this question. Answer choices A and B are not correct ,because they occurred before the captivity began. Answer choices D and E are incorrect because their eighteenth anniversaries (August 31, 2009 and January 1, 2010) happened after she escaped from captivity and regained her freedom. This leaves only C) July 25, 1991 as a viable answer choice. A person born on that date was born 45 days into the captivity, and turned 18 over a month before August 26, 2009, the day the captivity ended.

Example 6
In North America, daylight saving time ends on the first Sunday of November. Which of the following is true?

 * A) Daylight saving time cannot end on November 2.
 * B) Daylight saving time always ends exactly 21 days before the last Sunday in November.
 * C) Daylight saving time cannot end on November 6.
 * D) Daylight saving time cannot end on the same date two years in a row.
 * E) Daylight saving time sometimes ends later than November 11.

Solution
November always has 30 days. If the 2nd falls on a Sunday, then so do the 9th, 16th, 23rd, and 30th. Therefore, daylight saving time can end on November 2, and if it does it is not 21 days before the last Sunday of the month, but 28 days. Eliminate A and B. If November begins on a Tuesday, its Sundays are the 6th, 13th, 20th, and 27th, so the end of daylight saving time can fall on November 6, so answer choice C is incorrect. Eliminate C. With choices A, B, and C out of the way, two answer choices remain. Answer choice E is incorrect because any given period of seven days contains a Sunday, so the latest date that daylight saving time can end is November 7. Even when November 11 falls on a Sunday, it is not the first Sunday of the month, because the 4th falls on a Sunday as well. Eliminate E. This leaves answer choice D, which is correct because a date can never fall on the same day of the week twice in a row because 365 days is not a multiple of 7 days, and 366 isn’t either. Therefore, daylight saving time never ends on the same date two years in a row. The answer is D.

Example 7
On April 6, 2003, residents of the United States “lost” one hour of sleep as daylight saving time began in all parts of the country except Arizona and Hawaii. When local time was about to reach 2:00 am, local time jumped forward one hour, so that 01:59:59 was immediately followed by 03:00:00. If a random point was chosen uniformly from April 6, 2003, what is the probability that it is before 12:00:00 noon?

Solution
Be very careful. Before you bask in the warm glow of success, the answer is not one-half. On 363 days of the year, noon is indeed the midpoint of the day. The day that daylight saving time begins is one of two annual exceptions, the other being the day that daylight saving time ends. Because local time skipped an hour, the day lasted only 23 hours instead of the usual 24 hours. Likewise, since the period between midnight and noon includes the moment the clocks changed by one hour, it too was shortened one hour from 12 hours to only 11 hours. Since any given point in the day is equally likely to be chosen, the answer is 11/23, or approximately 47.83%.

title: Mixed Real World Math Problems


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Biographies/William Philip Bechervaise/Notes

William Philip Bechervaise
Total - More than 1 + 62 + 72 + 266 + 316 + 40 = 757 articles transcribed

1840s

 * Transcriptions and Notes - William Philip Bechervaise - 1840s - 1 transcription and note

1850s

 * Transcriptions and Notes - William Philip Bechervaise - 1850s - 62 transcriptions and notes

1860s

 * Transcriptions and Notes - William Philip Bechervaise - 1860s - 72 transcriptions and notes

1870s

 * Transcriptions and Notes - William Philip Bechervaise - 1870s - 266 transcriptions and notes

1880s

 * Transcriptions and Notes - William Philip Bechervaise - 1880s - More than 316 transcriptions and notes

1890s

 * Transcriptions and Notes - William Philip Bechervaise - 1890s - More than 40 transcriptions and notes

1900s

 * Transcriptions and Notes - William Philip Bechervaise - 1900s - More than 1 transcriptions and notes

1910s

 * Transcriptions and Notes - William Philip Bechervaise - 1910s - More than 1 transcriptions and notes

1920s

 * Transcriptions and Notes - William Philip Bechervaise - 1920s - More than 1 transcriptions and notes

1930s

 * Transcriptions and Notes - William Philip Bechervaise - 1930s - More than 1 transcriptions and notes

1940s

 * Transcriptions and Notes - William Philip Bechervaise - 1940s - More than 1 transcriptions and notes


text:
Free Knowledge Culture Calendar/March 7

Today in 1917 the computing pioneer Betty Holberton was born. She was responsible for much of the software for the UNIVAC system and created its C-10 instruction code, the first mnemonic code and mother of all modern programming languages. She went on to work on the programming language COBOL and was the driving force behind the standardization of FORTRAN. Grace Hopper called her the best programmer she ever knew. She also invented breakpoints for computer debugging, developed an early precursor to today’s compilers (her Sort Merge Generator), and was perhaps the first computer musician.

title: Free Knowledge Culture Calendar/March 7


text:
Free Knowledge Culture Calendar/May 6

The first description of the C-10 instruction code dates from today in 1949. C-10 is the first mnemonic code and the ancestor of modern programming languages. It was created for the UNIVAC system by Betty Holberton, who was part of a team of mostly female software engineers, like most programmers before programming was considered prestigious.

title: Free Knowledge Culture Calendar/May 6


text:
Free Knowledge Culture Calendar/November 4

Today in 1952 millions of people got introduced to electronic computers when the television network CBS calculated an accurate prediction of the election of Dwight D. Eisenhower on their fifth build of a UNIVAC I system. When the machine predicted against all other predictions, the head of the news team decided to hush up the exact prediction, until the actual result fell within 1 % and an embarrassed newscaster admitted the cover-up.


text:
Free Knowledge Culture Calendar/June 25

Today in 1945 Herman Goldstine privately began circulating John von Neumann’s initial paper on what is now known as the von Neumann architecture.

title: Free Knowledge Culture Calendar/June 25


text:
User:Jlaidman

Over at Wikipedia: https://en.wikipedia.org/wiki/User:Jlaidman

title: User:Jlaidman


text: User:PinkAmpersand

title: User:PinkAmpersand


text:
Free Knowledge Culture Calendar/August 4

Today is the birthday of Frances Allen. She laid the foundation for modern optimizing compilers and worked on code-breaking during the Cold War.


text:
Free Knowledge Culture Calendar/December 27

Today is the birthday of Jean Bartik. She and did pioneering work on the ENIAC, BINAC and UNIVAC I systems. She assembled and trained the team that converted the ENIAC into a stored-program computer. The ENIAC led to the development of the computer industry. At a time when only the engineering of the hardware of computers was considered prestigious and therefore dominated by men, women were then given the job of debugging and programming these machines – and created the field of programming. She was also one of the first programmers in the U.S. Army and programmed the first missile guidance computer.


text:
Free Knowledge Culture Calendar/September 25

Today is the birthday of Mary Allen Wilkes. After working on other early computers like the IBM 709 and TX-2, she developed the operating system for the first minicomputer, the LINC Assembly Program 6, one of the first interactive PC operating systems, and designed the LINC console. She was the first home computer user. Later, she pursued her old dream of becoming a lawyer, which her mentors had previously dissuaded her from because she was a woman.


text:
Transportation Geography and Network Science/Shared micromobility networks

Background
Shared Micromobility is a range of small and lightweight vehicles made available for shared use to individuals on a short-term basis for a price or free . The station-based bicycle-sharing system allows people to borrow a bike from a station and return it at another station belonging to the same system. There are docks in each station as special racks to lock bikes. The dock controlled by the computer will release the bike after the user enters payment information. To return the bike, the user needs to lock it by moving it into an empty dock. Other systems are the short-term checkout, the long-term checkout, the coin deposit stations and the dockless.

Devices
Shared Micromobility devices can be human-powered or electric. The e-scooter, bike and e-bike are the mainstream in 2020. Human-powered devices are considered to be low speed (top speed of 8 miles per hour (mph)), while electric devices can have sped up 20 mph . Any vehicle with an internal combustion engine cannot be defined as micromobility, nor can devices with top speeds above 20mph.

Usage in the United States
This bar graph presents the usage of shared micromobility in the United States from 2010 to 2019. Usage measures the number of the trip generated by riding those devices. In the first three years, the usage of shared micromobility gradually increased year by year, while the data is doubled in the fourth year, then it backs to steady development. With the introduction of new technologies scooter and dockless bike share in 2018, more users entered the market, and the trip increased dramatically from this year. In 2019, Station based bike share maintained a continuous growth trend and reached 40 million trips, and dockless e-bikes had the same growth trend (10M trips), while the usage of scooters surged to 86 million trips .

Shared Micromobility as A Network
Wu and Kim (2020) demonstrate how shared micromobility networks can be represented as a directed and weighted graph $$G = (V, E, w)$$. Their work focuses on the station-based bike sharing system, but these concepts can also be applied to dockless system and other sharing systems.

Vertices
Vertices represent bike stations (nodes).

Edges
Edges represents links connecting any two bike stations.

The weight of edges
Weight is defined as the cycling distance between two stations.

The Availability of the Trip between Two Stations
A = {aij} is an adjacent matrix representing the graph in a new way. The aij ranges from 0 to 1, indicating if there is at least one trip from the station i to station j.

Network structure
The degree distribution is the proportion of k-degree nodes over the whole network, which is written as:
 * $$P(k) = \frac{n(k)}{\sum\limits_{j=1}^\infty n(j)}$$

where $$n(k)$$ is the number of nodes that have a degree $$k$$ .

The average path length is the average number of steps along the shortest paths for all node pairs in the entire network, which is measured by:
 * $$L = \frac{1}{n*(n-1)}\sum\limits_{i \neq j} d_{ij}$$

where $$d_{ij}$$is the number of edges through the shortest path between node $$i$$ and node $$j$$.

The local clustering coefficient is used to measure the probability that the neighborhood of $$i$$ can be connected, calculated by:
 * $$C_{i} = \frac{E_{i}}{r_{i}(r_{i}-1)}, k_{i} \geq 2$$

where $$Ei$$ is the actual number of edges between the connected neighbors of the node $$i$$, and $$r_{i}$$ is the number of neighbors of the node $$i$$.

The neighbors Ni of the node $$i$$ are expressed as:
 * $$ N_{i} = \{v_{j}: a_{ij} = 1 \lor a_{ji} = 1\}$$

The global clustering coefficient is the ratio of the number of closed triplets to the total number of triplets, calculated by:
 * $$ C = \frac{number\; of\; closed\; triplets}{number\; of\; all\; triplets}, 0 \leqslant C \leqslant 1 $$

Node centrality
In order to measure connectivity, accessibility, and intermediateness of stations in bike-sharing networks respectively, Wu and Kim measured following centrality indices.

Degree centrality:
 * $$C_{D}(i) = k_{i}^{in} + k_{i}^{out}$$
 * $$k_{i}^{in} = \sum\limits_{j=1}^n a_{ji}$$
 * $$k_{i}^{in} = \sum\limits_{j=1}^n a_{ij}$$

(if there is a trip from node $$i$$ to node $$j$$, $$a_{ij} = 1$$, otherwise $$a_{ij} = 0$$)

Closeness centrality:
 * $$C_{C}(i) = \sum\limits_{j=1}^n \frac{1}{d_{ji}}$$

where $$d_{ji}$$ is the shortest path length from node $$j$$ to the given node $$i$$.

Betweenness centrality :
 * $$C_{B}(i) = \sum\limits_{j \neq k} \frac{n_{kj}(i)}{n_{kj}}$$

where $$n_{kj}$$ is the total number of shortest paths from node $$k$$ to node $$j$$, and $$n_{kj}(i)$$ is the number of shortest paths that pass through the node $$i$$.

Spatial autocorrelation analysis
Wu and Kim conducted this analysis to measure the degree of clustering among observations in geographical space.

The global spatial autocorrelation indicator, called Global Moran's I, can be measured by:
 * $$I = \frac{n}{S_{0}} \frac{\sum\limits_{i=1}^n \sum\limits_{j=1}^n w_{i,j}(x_{i} - \bar x)}{\sum\limits_{i=1}^n(x_{i} - \bar x)^2}$$

where $$n$$ is the number of observations;

$$x$$ is the variable of interest;

$$i,j$$ is the spatial units;

$$\bar x$$ is the mean of $$x$$;

$$w_{i,j}$$ is the matrix of spatial weights which is expressed by the inverse distance between $$x_{i}$$ and $$x_{j}$$;

$$S_{0}$$ is the sum of all spatial weights.

The local indicator of spatial association (LISA) can be measured by:
 * $$I_{i} = \frac{(x_{i}- \bar x)}{m} \sum\limits_{j=1}^n w_{i,j}(x_{j}- \bar x)$$

where $$m$$ is the variance of $$x$$.

Small World
Wu and Kim summarized the network structure measures of the five bike-sharing networks compared to those of random networks with the same number of nodes and edges. The findings show these bike-sharing networks have a shorter average path length and a larger global clustering coefficient, which indicate that bike-sharing networks have small-world properties.

Not a Scale-Free Network
Wu and Kim also looked for scale-free network features among five bike-sharing networks, and found that the cumulative degree distributions of the network in Washington, D.C. follows a power-law with exponential cutoff distribution, while other networks follow an exponential distribution.


text:
Type-oriented programming/Type variance

Consider the following type hierarchy:

type A {}

type B : A {}

type F[T] {}

Without type arguments,  is a type operator while  and   are proper types. In general, neither is a subtype of the other. However it may sometimes make sense for them to be in a subtype relation depending on the hierarchy of their argument(s). If we declare  as follows

type F[cov T] {}

then  will be a subtype of  because   is a subtype of. Conversely, if we declare  as

type F[con T] {}

then  will be a subtype of. In the former case, we say that  is covariant in its type argument whereas in the latter case its contravariant (since the hierarchy is reversed).

A real-world example of type variance are function types. When we expect a function whose return type is (that is, of type  ), we can always use a function of type  in its stead. On the other hand, when we expect a function whose argument is of type  (that is, of type, we can always use a function of type  in its stead. In sum, function types are covariant in their return type and contravariant in their arguments’ types.

NB: The pseudocode can be tried out using the Funcy app, which can be downloaded for free from Apple’s App Store (iOS/macOS), Google Play (Android) or Amazon Appstore. The code to be executed must be placed in a  block.

title: Type-oriented programming/Type variance