DOCSLIB.ORG

Cockcroft: a Novel This One, the Comprehensive Compilation Lutely Fundamental Discovery

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Cockcroft: a Novel This One, the Comprehensive Compilation Lutely Fundamental Discovery ~7~~-------------------------------------SPRINGBCXJKS------------------------N_A_ru_~__ v_o_L._Jo_s_~_AP __ Rr_L_r9M_ same, when it's compiled as successfully as what was in the sheer physics of it an abso­ Cockcroft: a novel this one, the comprehensive compilation lutely fundamental discovery. The authors perspective undeniably earns its place in the library. of this book take in their stride Cockcroft I was an admirer of Cockcroft, a fine, and Walton's being made to wait so long­ William Cooper stocky, sensible, cautious Yorkshireman, theirs not to reason why, they say. But what who indulged in a minimum of speech and about ours? Did it take the Nobel Cockcroft and the Atom. in practically no change of facial committee nineteen years to recognize the By Guy Hartcup and T.E. Allibone. expression. (That expression was neverthe­ experiment as breaking open an entirely Adam Hilger, Bristol!Heyden, Phila- less amiable, thoughtful, smiling.) If one new line of powerful experiments to be delphia: 1984. Pp.320. £18.95, $34. addressed a remark to him, it was only made with particle-accelerators? Or did it when, after the ensuing silence, he either take those members who opposed the took the famous black notebook out of his award all that time to disappear from the SrNCE the title of Hartcup and Allibone's pocket or actually said something, that one scene? Or what? Someone must know. book may sound a bit vague, perhaps I knew for certain that he'd heard. It gave me There's a fascinating detail I should really should begin by saying what Cockcroft and lasting pleasure to think that at a dinner­ like to be told. the A tom is about. It does not set up- as it party in his house I'd made him burst into Chadwick, speaking clearly for the seems to me - to be a full-dress biography laughter - till I saw in this book a photo­ "physics-is-physics" school, said of of John Cockcroft (1897-1967), or a graph of him laughing with George Cockcroft: history of atomic science during the For example, his knowledge is wide but it is first half of the twentieth century; not at all profound; his views are of rather a rather to be planned as a sort of docu- dull everyday hue. On the other hand his mentary about the context of events in temper is so equable and his patience and which Cock croft's life, as scientist and persistence so inexhaustible that we can put man of affairs, was central, of events in lively and relatively irresponsible men who in the world of atomic physics that he have the real feeling for research without influenced or that influenced him. fear of upsetting the balance. Does the plan succeed? For most I sense a pleasing Jane Austen-ish readers I imagine the answer will be a snobbery about the physics-is-physics straight "yes": for myself, some mild school to which Cockcroft was neither reservations. The book has been born nor bred. He was an applied extensively "researched", as it is now physicist. Between leaving school and called - records have been consulted, turning up at Cambridge in 1922 to read letters read, people interviewed; the for the Mathematical Tripos, he had facts laid end-to-end in chronological taken a mathematics degree at order. "A comprehensive compil­ Manchester University, served as a ation" is the phrase that springs to signaller in the trenches at Passchen­ mind. (The mother-and-father of the daele, returned to Manchester Tech to comprehensive compilation is of take a degree in electrical engineering course the computer.) Every event is while doing a Metro-Vick apprentice­ noted, every participant named. ship. Yet how right Chadwick's intim­ Speaking as a novelist- and why not, ations turned out to be, of what Cock­ if there is a fresh view to be added croft could be entrusted with, both thereby? - I find something Zola­ inside and outside the world of physics esque about the authors' naturalistic - spending the early years of the piling on of detail, maintaining The Cockcroft-Walton accelerator, April 1932, with Second World War on the vital practic­ throughout exactly the same degree of Ernest Walton seated to observe the scintillations. alities of radar; then taking over the detail: what I miss is Zola-esque art; that is Gamow. Well, Gamow was a funny man. wartime atomic scientists' team in to say, in down-to-earth terms, an author's It was a theoretical memorandum Montreal and Chalk River; then coming personal voice sounding through, an of Gamow's which sowed the seed of the back to run them in Harwell, each team author's personal intelligence commenting Cockcroft-Walton "atom-splitting" ex­ having its contingent of "lively men with a and interpreting, an author's personal periment, the first of its kind, in 1932. real feeling for research". (As I was party literary talent - the things that make one Cockcroft cottoned on to what Gamow to appointing many of the Harwell contin­ want to read a book for itself, as well as for was saying about bombarding elements gent, I should be the last person to say any the information it contains. with protons, and he addressed to Ruther- of them were "relatively irresponsible".) ! don't doubt that many readers will feel ford a calculation (reproduced in this "Without upsetting balance." That I'm asking too much: out of 100 ears on book) that led to the famous experiment exactly describes Cockcroft's reign at which my mild strictures fall, 98 will being set up. Then something odd hap­ Harwell from 1946 to 1958, during which probably be deaf to them. Just as well, pened. Using a lithium target bombarded he directed some of its most important perhaps, since the comprehensive compil- with a beam of protons, Cockcroft and research: he may have been neither a super ation is with us, and will be so to an Walton began by looking for gamma-rays; administrator nor a born manager - but increasing extent. (Yesterday a youthful and it was when Rutherford, fed up with the place balanced. American pupil of mine said to me en thus~ their getting no results for a couple of years The authors observe that Cockcroft had iastically: "The word-processor makes from their electroscopes, told them to his failures and disappointments, made his writing so easy!" Just so.) However- to install fluorescent screens, that they mistakes. He made a mistake - astonish­ be fair- one can't help but feel that all the promptly picked up the alpha-particles into ingly against caution - with his over­ facts are there. Yet on some pages there are which the lithium atoms had been split; a optimism about the experiments aimed at as many as a dozen names, normally far too prime experiment, for which the two of generating power from fusion. And his many for comfortable reading. Comfort- them were awarded a Nobel prize for private hopes of going back to his old able enough for me in this case, because physics - nineteen years later. James college, St John's, Cambridge, were often half of them were of men I'd come Chadwick, for discovering the neutron at dashed when, in a magisterial election across myself in my time; but for the com- about the same time got his Nobel in three which reminded him and his wife of C.P. fort of other readers I'm not so sure. All the years - very properly, for he had made Snow's The Masters, the Fellows elected © 1984 Nature Publishing Group _N_AT_u~~~vo~L~.n~~~~~RI_L_I~~----------------------SPRINGBQQKS:------------------------------------~'85 the Senior Tutor, and not Cockcroft, to be logical statements, it is nevertheless their Master. The upshot was a turn in his A feeling for the saturated with anomalies that Comfort career, a definitive turn to Whitehall and thinks support this Eastern insight. national affairs. It is interesting to unfathomable Consider the notorious EPR (Einstein­ speculate whether, if he had gone back to Martin Gardner Podolsky-Rosen) paradox, invented by Cambridge then, he would have played a Einstein and two associates as a thought comparable part in first national and later Reality and Empathy: Physics, Mind and experiment, but which recently has international affairs (though in a less Science in the 21st Century. received strong support from laboratory definitive way he was already embarked on By Alex Comfort. experiments. Two photons (in one version) both.) He was persuaded to join the State University of New York Press: are emitted in opposite directions by an Defence Research Policy Committee. As a 1984. Pp.272. Hbk $39.50; pbk $12.95. interaction that gives them opposing spins. committee-member in the conventional In QM, neither particle has a definite spin sense, he was practically a non-starter, for until measured, yet the two are so corre­ the simple reason that he rarely said DR ALEx Comfort, trained in classics at lated that if you measure A, thereby anything; but that didn't mean he was not Cambridge University, is the British geron­ creating, say, a plus spin, B will acquire a cogitating, participating and resolving on tologist who made a fortune with his best­ minus spin even though it may be light action. His action took place outside the sellers TheJoyofSexandMoreJoyofSex. years away. It is worse than that. If A is committee-room, in private meetings with Discussions with bright students at the measured a second time, it again will the members and other people one at a Neuropsychiatric Institute, University of acquire plus or minus spin with equal time.
Load more

Recommended publications
  • Appendix E Nobel Prizes in Nuclear Science
    Nuclear Science—A Guide to the Nuclear Science Wall Chart ©2018 Contemporary Physics Education Project (CPEP) Appendix E Nobel Prizes in Nuclear Science Many Nobel Prizes have been awarded for nuclear research and instrumentation. The field has spun off: particle physics, nuclear astrophysics, nuclear power reactors, nuclear medicine, and nuclear weapons. Understanding how the nucleus works and applying that knowledge to technology has been one of the most significant accomplishments of twentieth century scientific research. Each prize was awarded for physics unless otherwise noted. Name(s) Discovery Year Henri Becquerel, Pierre Discovered spontaneous radioactivity 1903 Curie, and Marie Curie Ernest Rutherford Work on the disintegration of the elements and 1908 chemistry of radioactive elements (chem) Marie Curie Discovery of radium and polonium 1911 (chem) Frederick Soddy Work on chemistry of radioactive substances 1921 including the origin and nature of radioactive (chem) isotopes Francis Aston Discovery of isotopes in many non-radioactive 1922 elements, also enunciated the whole-number rule of (chem) atomic masses Charles Wilson Development of the cloud chamber for detecting 1927 charged particles Harold Urey Discovery of heavy hydrogen (deuterium) 1934 (chem) Frederic Joliot and Synthesis of several new radioactive elements 1935 Irene Joliot-Curie (chem) James Chadwick Discovery of the neutron 1935 Carl David Anderson Discovery of the positron 1936 Enrico Fermi New radioactive elements produced by neutron 1938 irradiation Ernest Lawrence
    [Show full text]
  • Bibliography
    Bibliography F.H. Attix, Introduction to Radiological Physics and Radiation Dosimetry (John Wiley & Sons, New York, New York, USA, 1986) V. Balashov, Interaction of Particles and Radiation with Matter (Springer, Berlin, Heidelberg, New York, 1997) British Journal of Radiology, Suppl. 25: Central Axis Depth Dose Data for Use in Radiotherapy (British Institute of Radiology, London, UK, 1996) J.R. Cameron, J.G. Skofronick, R.M. Grant, The Physics of the Body, 2nd edn. (Medical Physics Publishing, Madison, WI, 1999) S.R. Cherry, J.A. Sorenson, M.E. Phelps, Physics in Nuclear Medicine, 3rd edn. (Saunders, Philadelphia, PA, USA, 2003) W.H. Cropper, Great Physicists: The Life and Times of Leading Physicists from Galileo to Hawking (Oxford University Press, Oxford, UK, 2001) R. Eisberg, R. Resnick, Quantum Physics of Atoms, Molecules, Solids, Nuclei and Particles (John Wiley & Sons, New York, NY, USA, 1985) R.D. Evans, TheAtomicNucleus(Krieger, Malabar, FL USA, 1955) H. Goldstein, C.P. Poole, J.L. Safco, Classical Mechanics, 3rd edn. (Addison Wesley, Boston, MA, USA, 2001) D. Greene, P.C. Williams, Linear Accelerators for Radiation Therapy, 2nd Edition (Institute of Physics Publishing, Bristol, UK, 1997) J. Hale, The Fundamentals of Radiological Science (Thomas Springfield, IL, USA, 1974) W. Heitler, The Quantum Theory of Radiation, 3rd edn. (Dover Publications, New York, 1984) W. Hendee, G.S. Ibbott, Radiation Therapy Physics (Mosby, St. Louis, MO, USA, 1996) W.R. Hendee, E.R. Ritenour, Medical Imaging Physics, 4 edn. (John Wiley & Sons, New York, NY, USA, 2002) International Commission on Radiation Units and Measurements (ICRU), Electron Beams with Energies Between 1 and 50 MeV,ICRUReport35(ICRU,Bethesda, MD, USA, 1984) International Commission on Radiation Units and Measurements (ICRU), Stopping Powers for Electrons and Positrons, ICRU Report 37 (ICRU, Bethesda, MD, USA, 1984) 646 Bibliography J.D.
    [Show full text]
  • The History and Impact of the CNO Cycles in Nuclear Astrophysics
    Phys. Perspect. 20 (2018) 124–158 Ó 2018 Springer International Publishing AG, part of Springer Nature 1422-6944/18/010124-35 https://doi.org/10.1007/s00016-018-0216-0 Physics in Perspective The History and Impact of the CNO Cycles in Nuclear Astrophysics Michael Wiescher* The carbon cycle, or Bethe-Weizsa¨cker cycle, plays an important role in astrophysics as one of the most important energy sources for quiescent and explosive hydrogen burning in stars. This paper presents the intellectual and historical background of the idea of the correlation between stellar energy production and the synthesis of the chemical elements in stars on the example of this cycle. In particular, it addresses the contributions of Carl Friedrich von Weizsa¨cker and Hans Bethe, who provided the first predictions of the carbon cycle. Further, the experimental verification of the predicted process as it developed over the following decades is discussed, as well as the extension of the initial carbon cycle to the carbon- nitrogen-oxygen (CNO) multi-cycles and the hot CNO cycles. This development emerged from the detailed experimental studies of the associated nuclear reactions over more than seven decades. Finally, the impact of the experimental and theoretical results on our present understanding of hydrogen burning in different stellar environments is presented, as well as the impact on our understanding of the chemical evolution of our universe. Key words: Carl Friedrich von Weizsa¨cker; Hans Bethe; Carbon cycle; CNO cycle. Introduction The energy source of the sun and all other stars became a topic of great interests in the physics community in the second half of the nineteenth century.
    [Show full text]
  • Talk CAS 2019 Accelerators & Discoveries.Pdf
    Particle accelerators, instruments of discovery in physics Philippe Lebrun Director, Joint Universities Accelerator School CAS Vysoke (High Tatra), 9 September 2019 Foreword • The aim of this lecture is to illustrate the joint evolution of elementary particle physics and their essential tools, the particle accelerators, cross-fertilized by the «pull» of the former and the «push» of the latter, throughout the 20th and beginning of the 21st century • The presentation approximately follows chronological order, though with some necessary deviations imposed by the non-linear developments in the history of science and technology • Not all the major discoveries in particle physics, and not all the major high- energy accelerators are discussed; rather, the lecture addresses a selection of salient cases deemed of interest to the purpose of the discussion • The lecture is targeted to students of accelerator physics and technology, not of particle physics Ph. Lebrun CAS 2019 Vysoke (High Tatra) 2 Isaac Newton Opticks (1704) There are agents in Nature able to make the particles of bodies stick together by very strong attractions. And it is the business of Experimental Philosophy to find them out. The smallest particles of matter may cohere by the strongest attractions. Ph. Lebrun CAS 2019 Vysoke (High Tatra) 3 John Dalton A New System of Chemical Philosophy (1808) John Dalton introduces atoms to explain why elements always react in ratios of small whole numbers Chemical analysis and synthesis go no farther than to the separation of particles one from another, and to their reunion. No new creation or destruction of matter is within the reach of chemical agency… All the changes we can produce consist in separating particles that are in a state of cohesion or combination, and joining those that were previously at a distance Ph.
    [Show full text]
  • Contributions of Civilizations to International Prizes
    CONTRIBUTIONS OF CIVILIZATIONS TO INTERNATIONAL PRIZES Split of Nobel prizes and Fields medals by civilization : PHYSICS .......................................................................................................................................................................... 1 CHEMISTRY .................................................................................................................................................................... 2 PHYSIOLOGY / MEDECINE .............................................................................................................................................. 3 LITERATURE ................................................................................................................................................................... 4 ECONOMY ...................................................................................................................................................................... 5 MATHEMATICS (Fields) .................................................................................................................................................. 5 PHYSICS Occidental / Judeo-christian (198) Alekseï Abrikossov / Zhores Alferov / Hannes Alfvén / Eric Allin Cornell / Luis Walter Alvarez / Carl David Anderson / Philip Warren Anderson / EdWard Victor Appleton / ArthUr Ashkin / John Bardeen / Barry C. Barish / Nikolay Basov / Henri BecqUerel / Johannes Georg Bednorz / Hans Bethe / Gerd Binnig / Patrick Blackett / Felix Bloch / Nicolaas Bloembergen
    [Show full text]
  • Structure and Properties of Nuclei (1932 -1935)
    Structure and Properties of Nuclei (1932 -1935) An Annotation by C. F. von Weizsacker, Starnberg Heisenberg's work on nuclear physics was only an episode for him, but an im­ portant one. The work consists mainly of the three publications of 1932 and 1933, stimulated by the discovery of the neutron, with some echoes later in the 1930s. In order to understand the kind of interest Heisenberg took in nuclear physics it may be useful to recall how the concept of nuclear physics came about historically. The concept of the atom sprang from the branch of Greek philosophy con­ nected with the names of Leucippus and Democritus. Atoms were supposed to be the ultimate constituents of everything real; they should have no parts, hence be indivisble. This doctrine was not adopted in the philosophy of the next two mil­ lenia, from Plato to Hegel. The philosophers recognized the inner contradictions of the concept of extended atoms. Kant realized that the regions of space filled by an extended atom are obviously filled also by the parts of the atom; then it might be just an empirical question, whether we can divide these parts. Happily naive towards this problem, the chemists around 1800 introduced ex­ tended atoms of different types as the fundamental constituents of different chemical elements. By 1900 the empirical success of this model had become in­ disputable. It served in physics to establish the statistical foundation of thermo­ dynamics. Ludwig Boltzmann argued against the continuum theory of matter, as advocated again by Ernst Mach and Wilhelm Ostwald, that a thermodynamical equilibrium among the infinitely many degrees of freedom of a dynamical continuum system was impossible.
    [Show full text]
  • ERNEST WALTON – IRELAND’S NOBEL SCIENCE LAUREATE by William Reville, University College, Cork
    ERNEST WALTON – IRELAND’S NOBEL SCIENCE LAUREATE By William Reville, University College, Cork. Most people would reckon they had been given an easy question if asked - ‘Name Ireland’s Nobel Prize Winners’. The names spring readily to mind – William Butler Yeats (1923), George Bernard Shaw (1925), Sam Beckett (1969), Betty Williams and Mairead Corrigan (1976), Seamus Heaney (1995), John Hume and David Trimble (1998). But this answer would be incomplete. Ireland has produced another winner of the Nobel Prize, the only Irish person to win the prize for science, Ernest Thomas Sinton Walton (1903-1995). Walton was awarded the Nobel Prize in Physics in 1951, jointly with J.D. Cockroft, for ‘splitting the atom’. Ernest Walton was born in Dungarvan, Co. Waterford, in 1903, son of Methodist Minister John Walton and Anne E. Sinton. Ernest received early education in Banbridge and Cookstown and secondary education at Methodist College, Belfast. He entered Trinity College Dublin (TCD) in 1922 on scholarship and took a first class honours degree in Physics and Mathematics (1926), followed by an M.Sc. degree in 1927. He won a research scholarship to work with Ernest Rutherford (1871-1937) at the Cavendish Laboratory, Cambridge. At the time physics was going through a golden era. Albert Einstein had revolutionised the way physics looked at the world with his theory of relativity (1905, 1915). Rutherford had discovered that atoms have a tiny dense central core, the atomic nucleus, in 1910. The atomic nucleus is surrounded by a cloud of electrons and Niels Bohr had described how the electrons orbit the nucleus in 1913.
    [Show full text]
  • Main Attributes of Nuclides Presented in This Book
    Appendix A Main Attributes of Nuclides Presented in This Book Data given in TableA.1 can be used to determine the various decay energies for the specific radioactive decay examples as well as for the nuclear activation examples presented in this book. M stands for the nuclear rest mass; M stands for the atomic rest mass. The data were obtained from the NIST and are based on CODATA 2010 as follows: 1. Data for atomic masses M are given in atomic mass constants u and were obtained from the NIST at: (http://www.physics.nist.gov/pml/data/comp.cfm). 2. Rest mass of proton mp, neutron mn, electron me, and of the atomic mass constant u are from the NIST (http://www.physics.nist.gov/cuu/constants/index. html) as follows: −27 2 mp = 1.672 621 777×10 kg = 1.007 276 467 u = 938.272 046 MeV/c (A.1) −27 2 mn = 1.674 927 351×10 kg = 1.008 664 916 u = 939.565 379 MeV/c (A.2) −31 −4 2 me = 9.109 382 91×10 kg = 5.485 799 095×10 u = 0.510 998 928 MeV/c (A.3) − 1u= 1.660 538 922×10 27 kg = 931.494 060 MeV/c2 (A.4) 3. For a given nuclide, its nuclear rest energy was determined by subtracting the 2 rest energy of all atomic orbital electrons (Zmec ) from the atomic rest energy M(u)c2 as follows 2 2 2 Mc = M(u)c − Zmec = M(u) × 931.494 060 MeV/u − Z × 0.510 999 MeV.
    [Show full text]
  • Cockcroft 120 Challenge
    Cockcroft 120 Challenge Background:- The Cockcroft Institute, based in Daresbury, Warrington, is a UK centre of excellence for particle accelerator physics research. The University of Liverpool Accelerator Science Cluster, a key academic research group within the institute, presents the Cockcroft 120 Challenge... 2017 marks the 120th anniversary of the birth of Sir John Cockcroft, the Nobel prize winner after whom the Cockcroft Institute is named. Cockcroft, alongside Ernest Walton, was awarded the 1951 Nobel prize for the splitting of atoms, a feat made possible by the development of the Cockcroft-Walton voltage multiplier. The voltage multiplier allowed Cockcroft and Walton to generate the 100’s of thousands of volts needed to accelerate the charged particles used in their experiments. To celebrate Cockcroft’s birth, we are asking you to conduct your own high voltage experiment and then to communicate your results. Electrostatic generators, such as Van de Graaff machines, can generate 100 kV+ at very low current, meaning that high voltage experiments can safely be carried out in the classroom. Remember, it requires around 30 kV for every cm of a spark’s length! To discover more about our research, please visit our websites: www.liverpool.ac.uk/physics/research/accelerator-physics/ www.cockcroft.ac.uk A Cockcroft Walton voltage multiplier. Located at the Cockcroft Institute, Daresbury Laboratory. The Competition:- We invite you to create a video of up to 30 seconds in length that demonstrates a high voltage experiment and offers some explanation of the physics involved. The creation of a spark is offered as a suggestion, but feel free to follow your own path! You may also want to consider hair raising experiments using a Van de Graaff generator, or the exploration of a fine beam tube.
    [Show full text]
  • Interrogating the Legend of Einstein's “Biggest Blunder”
    Interrogating the legend of Einstein’s “biggest blunder” Cormac O’Raifeartaigh§ and Simon Mitton§§ Full addresses of authors §School of Science and Computing, Waterford Institute of Technology, Cork Road, Waterford, Ireland. §§St Edmund’s College, University of Cambridge, Cambridge CB3 0BN, United Kingdom. Author for correspondence: [email protected] Short biographies of authors § Cormac O’Raifeartaigh lectures in physics at Waterford Institute of Technology, Ireland and is Visiting Associate Professor of Physics at University College Dublin. §§ Simon Mitton is a historian of science and Life Fellow of St Edmund’s College, University of Cambridge 1 Abstract It is well known that, following the emergence of the first evidence for an expanding universe, Albert Einstein banished the cosmological constant term from his cosmology. Indeed, he is reputed to have labelled the term, originally introduced to the field equations of general relativity in 1917 in order to predict a static universe, his “biggest blunder”. However serious doubts about this reported statement have been raised in recent years. In this paper, we interrogate the legend of Einstein’s “biggest blunder” statement in the context of our recent studies of Einstein’s cosmology in his later years. We find that the remark is highly compatible with Einstein’s cosmic models of the 1930s, with his later writings on cosmology, and with independent reports by at least three physicists. We conclude that there is little doubt that Einstein came to view the introduction of the cosmological constant term a serious error and that it is very likely that he labelled the term his “biggest blunder” on at least one occasion.
    [Show full text]
  • Downloaded the Top 100 the Seed to This End
    PROC. OF THE 11th PYTHON IN SCIENCE CONF. (SCIPY 2012) 11 A Tale of Four Libraries Alejandro Weinstein‡∗, Michael Wakin‡ F Abstract—This work describes the use some scientific Python tools to solve One of the contributions of our research is the idea of rep- information gathering problems using Reinforcement Learning. In particular, resenting the items in the datasets as vectors belonging to a we focus on the problem of designing an agent able to learn how to gather linear space. To this end, we build a Latent Semantic Analysis information in linked datasets. We use four different libraries—RL-Glue, Gensim, (LSA) [Dee90] model to project documents onto a vector space. NetworkX, and scikit-learn—during different stages of our research. We show This allows us, in addition to being able to compute similarities that, by using NumPy arrays as the default vector/matrix format, it is possible to between documents, to leverage a variety of RL techniques that integrate these libraries with minimal effort. require a vector representation. We use the Gensim library to build Index Terms—reinforcement learning, latent semantic analysis, machine learn- the LSA model. This library provides all the machinery to build, ing among other options, the LSA model. One place where Gensim shines is in its capability to handle big data sets, like the entirety of Wikipedia, that do not fit in memory. We also combine the vector Introduction representation of the items as a property of the NetworkX nodes. In addition to bringing efficient array computing and standard Finally, we also use the manifold learning capabilities of mathematical tools to Python, the NumPy/SciPy libraries provide sckit-learn, like the ISOMAP algorithm [Ten00], to perform some an ecosystem where multiple libraries can coexist and interact.
    [Show full text]
  • 50 Character Selection
    £50 character selection Between the launch and closure of the character selection process for the £50 note announced by the Governor on 2 November, we have received a total of 227,299 nominations from members of the public. This is the list of 989 eligible names that were suggested within the nomination period. This is only the preliminary stage of identifying eligible names for consideration: At this stage, a nomination has been deemed eligible simply if the character is real, deceased and has contributed to the field of science in the UK in any way. These names have not yet been considered by our Banknote Character Advisory Committee. We plan to announce the character for the new £50 banknote in Summer 2019. Aaron Klug Alister Hardy Augustus De Morgan Abraham Bennet Allen Coombs Austin Bradford Hill Abraham Darby Allen McClay Barbara Ansell Abraham Manie Adelstein Alliott Verdon Roe Barbara Clayton Ada Lovelace Alma Howard Barnes Neville Wallis Adam Sedgwick Andrew Crosse Baron Charles Percy Snow Aderlard of Bath Andrew Fielding Huxley Bawa Kartar Singh Adrian Hardy Haworth Angela Hartley Brodie Beatrice "Tilly" Shilling Agnes Arber Angela Helen Clayton Beatrice Tinsley Alan Archibald Campbell‐Swinton Anita Harding Benjamin Gompertz Alan Arnold Griffiths Ann Bishop Benjamin Huntsman Alan Baker Anna Atkins Benjamin Thompson Alan Blumlein Anna Bidder Bernard Katz Alan Carrington Anna Freud Bernard Spilsbury Alan Cottrell Anna MacGillivray Macleod Bertha Swirles Alan Lloyd Hodgkin Anne McLaren Bertram Hopkinson Alan MacMasters Anne Warner
    [Show full text]