bluuebunny/crossref_metadata_2025 huggingface dataset:
Transition metal‐catalyzed oxidation of atmospheric sulfur: Global implications for the sulfur budget
Authors: Alexander Becky , Park Rokjin J. , Jacob Daniel J. , Gong Sunling
Published: January 2009

We use observations of the oxygen‐17 excess (Δ17O) of sulfate in the Arctic to quantify the sulfate source from aqueous SO2 (S(IV)) oxidation by O2 catalyzed by transition metals. Due to the lack of photochemically produced OH and H2O2 in high latitudes during winter, combined with high anthropogenic SO2 emissions in the Northern Hemisphere, oxidation by O3 is predicted to dominate sulfate formation during winter in this region. However, Δ17O measurements of sulfate aerosol collected in Alert, Canada, are not consistent with O3 as the dominant oxidant and indicate that a S(IV) oxidant with near‐zero Δ17O values (O2) is important during winter. We use a global chemical transport model to interpret quantitatively the Alert observations and assess the global importance of sulfate production by Fe(III)‐ and Mn(II)‐catalyzed oxidation of S(IV) by O2. We scale anthropogenic and natural atmospheric metal concentrations to primary anthropogenic sulfate and dust concentrations, respectively. The solubility and oxidation state of these metals is determined by cloud liquid water content, source, and sunlight. By including metal‐catalyzed S(IV) oxidation, the model is consistent with the Δ17O magnitudes in the Alert data during winter. Globally, we find that this mechanism contributes 9–17% to sulfate production. The inclusion of metal‐catalyzed oxidation does not resolve model discrepancies with surface SO2 and sulfate observations in Europe. Oxygen isotope measurements of sulfate aerosols collected near anthropogenic and dust sources of metals would help to verify the importance of this sulfur oxidation pathway.
Helium 3 Isotope
Authors: Lane C. T.
Published: January 2009

In 1939 Alvarez and Cornog, at the University of California, discovered that helium gas present in the earth's atmosphere contained a stable isotope of mass 3.
A newsman looks at physicists
Authors: White Stephen
Published: January 2009

I have seen physicists in their natural habitats, which are the universities; at their roundups, which are the regular meetings of the American Physical Society; on the prowl at Almagordo, Las Cruces, Bikini, Washington, Brazil; at a good many way stations; and (once) in jail. I have seen them talking—on the whole very sensibly—on physics; a little less sensibly on more remote matters; and very foolishly about newspapers.
Italy
Authors: Bernadini G. , Longo C. , Pancini E.
Published: January 2009

The Centro per lo studio della Fisica Nucleare e delle particelle elementari, of the Consiglio Nazionale delle Ricerche, has recently built a small laboratory in the Alps for the investigation of cosmic radiation. This laboratory, now named “Laboratorio della Testa Grigia,” is situated at an altitude of almost 11,500 feet, near the upper station of the cable railway which climbs from the village of Breuil-Cervinia to Plateau Rosà.
Lens Surfaces
Authors: Schulz L. G.
Published: January 2009

In this paper a method is described by which evaporated lithium fluoride can be selectively deposited on lens surfaces to make the lenses free from spherical aberration.
American Physical Society
Authors: D. K. K.
Published: January 2009

Nothing short of a committee of at least five members—and in fact, certainly several more would be needed—could prepare a complete report of the Spring Meeting which the American Physical Society held in Washington as April passed into May of 1948.
American Institute of Physics 1947 Annual Report
Authors: Barton Henry A.
Published: January 2009

It is appropriate to borrow the title of the new “magazine for all physicists” to sum up certain aspects of the situation of physics today. Presumably the new magazine will continually do just that, and the title is well chosen.
The challenge of industrial physics
Authors: Robinson Howard A.
Published: January 2009

In physics, as in every other branch of human endeavor, there comes a time when each individual must consider for himself the future of his personal relationship with the science he is attempting to master. At the present moment, with the war years over, large numbers of students propose to join the ranks of the 10,000 or 12,000 of us in this country who have been educated in physics. While it is true that the colleges of the country, because of their increased enrollments, will be in a position to absorb an increased number of these younger people, many more of them will go into the industrial and government laboratories of the country.
Pocono conference
Authors: Feynman Richard P.
Published: January 2009

In spite of the fact that the Pocono Conference on theoretical physics lasted four days, there did not seem to be time enough to discuss everything that people wanted to. As one conferee remarked, we had to take time out to learn some new things about physics as we went along.
The Christmas lectures at the Royal Institution
Authors: Martin Thomas
Published: January 2009

Every year at Christmas a course of science lectures for young people is given at the Royal Institution in Albemarle Street, London. These Christmas Juvenile Lectures are a long-established and well-known feature of the Christmas holidays, competing for popularity with the pantomimes, circuses, and other entertainments of the season. They are intended for boys and girls at school, the sons and daughters of members of the Institution and of those of the public who are fortunate enough to obtain tickets. The historic lecture theatre of the Institution is always crowded, and it is seldom that there is enough accommodation for all those who wish to come. The large and appreciative audience at the course recently given (Christmas 1947) by Professor E. K. Rideal, on “Chemical Reactions: How They Work,” the one hundred and eighteenth in the series, is evidence of the fact that the lectures have lost none of their popularity.
The reality of neutrinos
Authors: Gamow George
Published: January 2009

In the year 1914 a young (at that time) British physicist, James Chadwick, who was sent to Germany to study the phenomena of radioactive decay, came across a rather interesting but, as it looked then, not very important discovery. He found that electrons emitted by radioactive substances in the process called beta transformation do not all possess the same velocity. In fact their velocities vary over a rather wide range.
The formation of stars
Authors: Spitzer Lyman
Published: January 2009

If research in astronomy had stopped in 1913, our knowledge of stellar evolution today would be in a satisfactory state. At that time astronomers had a plausible theory of a star's life cycle. Einstein's theory of relativity, advanced only a few years before, showed that mass and energy were interchangeable. It was therefore natural for astronomers to assume that stars were formed as large massive bodies which through successive century after century continued to radiate away matter. Ultimately most of the matter in a star, according to this picture, would be radiated away as light and heat. In this way all the stars, despite their large differences in mass, formed part of the same evolutionary sequence.
Accelerating atomic particles
Authors: Brobeck W. M.
Published: January 2009

In the last fifteen years, in most of the important universities and scientific institutions of the world, there have been built in physics laboratories a great many large and complicated machines which project beams of fast-moving atomic particles. These machines—the cyclotron, the betatron, the synchrotron, the synchrocyclotron, the linear accelerator, and the Van de Graaff generator—in their seeming superfluity hint that the physicist does not have what he wants, but that he is looking for it very hard.
Microscopy Symposium
Authors: T. C. F.
Published: January 2009

On June 10, 11, and 12, Armour Research Foundation of Illinois Institute of Technology and the physics department of the Institute sponsored the first joint symposium on electron and light microscopy. International in scope, the Chicago meeting was attended by more than three hundred microscopists, who heard papers on such subjects as metallography, pigments, electron diffraction, fibers, goniometry, fats, particle size determination, bacteriophage action, ultraviolet and infrared microscopy, and metal films evaporated in high vacuum. A portion of the formal program was devoted to phase microscopy, a recent modification which employs the light microscope in such a way as to enhance image contrast, thus enabling the microscopist to observe sections that cannot be examined adequately by conventional methods. The informal panel presentations discussed instrumentation for electron microscopy, preparation of metal surfaces for microscopic examination, and problems in high speed microtomy. In addition, the Symposium featured an instrument display and photographic exhibit. Tentative plans have been made to perpetuate the Symposium.
The Netherlands
Authors: Gorter C. J.
Published: January 2009

As described in a previous letter, scientific research, as well as most other research activity in Holland, is concentrated at the public universities. Student fees defray part of the expenses of these universities but at least three quarters of their expenses are met from public funds. These funds are allocated by Parliament on the proposal of the Minister of Education and, in the case of the Municipal University of Amsterdam, by the City Council on the proposal of the alderman concerned. Of course the Minister of Education and the alderman depend on the advice of the university authorities on details, and this advice is usually followed.
Infrared Detector
Authors: Fuson Nelson
Published: January 2009

Since infrared or heat radiation of wavelength longer than about one micron cannot be detected by visual or photographic means, physicists, besides pushing development of standard radiation detectors such as thermopiles and bolometers, have roamed far afield in their attempts to find new and more sensitive infrared detectors.
Motion in a Magnetic Field
Authors: Johnson M. H.
Published: January 2009

Classically a charged particle in a constant magnetic field moves in a circle whose plane is perpendicular to the magnetic field.
Science education in the United States
Authors: Philbrick F. A.
Published: January 2009

Many writers have noted that pragmatism is the chief trait of the American character, whether this is to be attributed to the cast of mind common in emigrants to the New World, or to the conditions of life that they found and developed there. And just as pragmatism has been the dominating philosophy taught in the universities, so in pedagogy has everything been subordinated to immediate and practical ends. In America, the battle for the inclusion of science in the curriculum was easily won. Money for laboratories has been generously provided—it has always been more readily available for buildings than for the men who teach in them—and the visible successes of modern science have given it enormous prestige as an academic subject. So greatly envied is the position of the scientist in the universities that his colleagues in other departments are tempted to describe their own subjects as sciences and themselves as scientists. Thus a historian who emigrates to America may find that he has become a social scientist, and in a recent book a psychologist goes so far as to say, “Scientists study and write about people and the world in which they live”—a definition which seems to include all possible topics.
Physics of chimneys
Authors: Achenbach Paul R.
Published: January 2009

Greek and Roman architects used chimneys in kitchens and baths, though they took great care to conceal them from view. Yet it was not until the twelfth century that the practice of allowing the smoke from a fire to pass out through a hole in the roof was changed in northern Europe to the use of a hollow flue leading upward from the fireplace by the wall.
Physics in Canada
Authors: Herzberg G. , Howlett L. E.
Published: January 2009

Canada has large natural resources but these have been only partially developed. The population is small and the area very large. Research is sponsored by a number of different administrative authorities. Consequently, organization assumes an even greater importance than usual if maximum success is to result. It is the intent of this article to give a brief survey of the nature of the work in Canadian physics and the method of its organization.
Any physics tomorrow?
Authors: Gamow George
Published: January 2009

Will the development of physics in the years to come always present us with ever broadening horizons offering limitless possibilities for further explorations, or is our science converging towards a complete and self-consistent system of fundamental physical knowledge with all the ground thoroughly explored and with no new striking discoveries to be expected?.
Televising science
Authors: Marshall Roy K.
Published: January 2009

There is a genuine thirst for scientific knowledge in most homes. Satisfying that thirst will, I believe, create a friendly attitude toward science and scientists which will favor the cause of science in the future. Science needs an informed and friendly public to back it up.
The physics of metals
Authors: Slater John C.
Published: January 2009

The International Union of Pure and Applied Physics held an International Conference on the Physics of Metals in Amsterdam on July 12–17, 1948, in connection with a meeting of its General Assembly. It was a popular meeting for Americans: thirty out of the 311 physicists in the official list of participants came from the United States, a delegation exceeded only by those from the Netherlands, which naturally had the greatest number, and Great Britain.
Astronomers Meet
Authors: Page Thornton
Published: January 2009

In a torrential downpou-such as drenched New Haven during the meetings of the American Astronomical Society, December 28–31, 1948, at Yale University, everyone looks more or less the same—but this alone could not account for the difficulty I had in distinguishing astronomers from physicists.
A.S.X.R.E.D.
Authors: Parrish William
Published: January 2009

The winter meeting of the American Society for X-ray and Electron Diffraction was held at Battelle Memorial Institute, Columbus, Ohio, December 16–18, 1948.
Josiah Willard Gibbs
Authors: Rukeyser Muriel
Published: January 2009

Willard Gibbs is the type of the imagination at work in the world. His story is that of an opening-up which has had its effect on our lives and our thinking; and, it seems to me, it is the emblem of the naked imagination—which is called abstract and impractical, but whose discoveries can be used by anyone who is interested, in whatever “field”—an imagination which for me, more than that of any other figure in American thought, any poet, or political, or religious figure, stands for imagination at its essential points.
Magnetic Servo
Authors: Bettis E. S.
Published: January 2009

Making a flexible servo system to satisfy the specialized control requirements of most laboratories is usually difficult and expensive.
Creative research
Authors: Smoluchowski Roman
Published: January 2009

It is a truism to state that progress in science depends upon the entire range of research, from the hypothetical extreme of observing and collecting facts to the equally hypothetical extreme of boldly running far ahead into the realm of pure speculation and intuition, thus giving spur to search for new facts. Nevertheless, it is often the case that a disproportionate weighting is accorded to research near the first extreme because of its easily tangible results.
APS at Berkeley
Authors: Segrè Emilio
Published: January 2009

The 290th meeting of the American Physical Society was held in Berkeley, California, from February 3 to 5, 1949. It was attended by over two hundred fellows and members of the Society, the largest attendance on record for a West Coast meeting. This remark occurs regularly in describing successive meetings, and is good evidence of the growing membership of the Society.
Magnetic Ion Source
Authors: Drukey D. L.
Published: January 2009

A high intensity ion source is desirable for accelerator work because one may then study reactions with smaller yields than if lower beam currents are used.
Institute Doings
Authors: Barton Henry A.
Published: January 2009

If the idea works out well there will be a joint meeting of the Member Societies of the Institute in the year 1951.
The Netherlands
Authors: Gorter C. J.
Published: January 2009

In a previous letter I described the slow birth of the Netherlands Foundation for Pure Research. I mentioned that, in spite of the fact that the bill about the foundation has not yet passed Parliament, the provisional council of the foundation has not delayed its activities. The Sub-Foundation for Research on Matter has been at work for three years.
Heavy Element Spectra
Authors: Fred Mark
Published: January 2009

Because spectrochemical analysis has proved useful in establishing the purity of very small samples of the new heavy elements as they were produced in turn by the Plutonium Project, photographs of the spectra of these elements have accumulated.
Geophysical Activity Increasing
Authors: Lyons Paul L.
Published: January 2009

The Society of Exploration Geophysicists met in St. Louis March 14–17. The group, organized in 1930, now numbers two thousand members, and as the word exploration in its title implies, is composed of men active in geophysical exploration—primarily for oil, and to a lesser extent for ores. The annual meeting in St. Louis was, as is usual, held jointly with the American Association of Petroleum Geologists and the Society of Economic Paleontologists and Mineralogists.
Pacific Science Congress
Authors: Gutenberg Beno
Published: January 2009

The Seventh Pacific Science Congress which was held in New Zealand during February 1949 was the first after the war. The Congresses are mainly intended to unite scientists in fields with special interest in the Pacific Ocean. Thus, pure physics is not represented, but there are divisions of geophysics, geology, meteorology, and oceanography, in addition to other sections such as botany, zoology, public health, anthropology, and social science.
Unesco: A work in progress
Authors: Bok Bart J.
Published: January 2009

The United Nations Educational, Scientific, and Cultural Organization is concerned with something very intangible—the minds of men. Unesco's purpose is to create through education, science, and culture a climate favorable to world peace. It is not a little mental Security Council that comes running with a first aid kit to patch up each threat to the peace. It is the organization that looks into the basic causes for war and suggests remedies for their removal. It is Unesco's function to encourage and support (the latter of course within the narrow limitations of its budget) activities that contribute effectively toward the creation of good relations between peoples.
Acoustics and Man
Authors: Steinberg J. C.
Published: January 2009

Twenty years ago on May 10–11, 1929 the formal organization and the first meeting of the Acoustical Society took place at Bell Telephone Laboratories in New York City. This event stemmed from the enthusiasm of a group of some forty interested people that had met on the preceding December 27, 1928.
n Equals One
Authors: Darrow K. K.
Published: January 2009

To witness the (50n«)th anniversary of a Society—n being zero or any positive integer—is an experience which, by and large, comes only once in a lifetime; indeed there are many lives that never include such an occasion, and few indeed are the careers which comprise two values of n. Such an opportunity was vouchsafed to the members and guests of the American Physical Society at Cambridge, Massachusetts, on June 16, 17, and 18, 1949; the value of n was one. The Society was founded on May 20, 1899, by some forty physicists who gathered in a very small lecture-room (Room 304) of Fayerweather Hall of Columbia University in New York City; the names of thirty-eight are on record, it is certain that a few have been lost to history. Of the thirty-eight, six are still living at the moment of this writing, but not one of them was able to attend the meeting. One, Frederick Bedell, was an Editor of the Physical Review from 1895 until 1922; this includes seventeen years of the period before that journal became the property of the Society, and counting these it is the longest period of service yet given us by anyone, except that of G. B. Pegram as Treasurer. The others are W. D. Bancroft, Bergen Davis, Marcia A. Keith, Isabelle Stone and F. A. Waterman. The first regular meeting of the Society was held on October 28, 1899. Two at least of those who attended it were at our Semi-Centennial Meeting: these are G. B. Pegram (Treasurer of the Society) and L. P. Wheeler. They were joined by 591 others who registered at the desk, and an unknowable number of still others who failed to register. This was the biggest summer meeting of our history, with one exception. Considering the season of the year, we may deem this a satisfactory attendance at the unique occasion, though a larger one would have been appropriate and welcome.
Meson Creation
Authors: Schiff L. I.
Published: January 2009

There is good experimental evidence that a substantial part of the soft electronic component of cosmic radiation originates in events high in the atmosphere that involve the collision of primary cosmic rays with air nuclei.
Science and Music
Authors: Bartholomew Wilmer T.
Published: January 2009

The twentieth anniversary meeting of the Acoustical Society of America gave opportunity for papers indulging in prospect and retrospect.
Molecular Symmetry Coordinates
Authors: Nielsen J. Rud , Berryman L. H.
Published: January 2009

In 1923 C. J. Brester showed, by elementary but cumbersome mathematical methods, that the normal vibrations of molecules or crystals can be classified in terms of their symmetry.
Tritium Target
Authors: Graves E. R.
Published: January 2009

When a triton reacts with a deuteron there are produced an alpha particle, a neutron, and an energy release of approximately seventeen million electron volts.
Terrestrial magnetism
Authors: Bullard E. C.
Published: January 2009

It has been known for many hundreds of years that a suitably suspended bar magnet will turn itself so that its axis lies roughly in a north-south direction. This unexpected and useful property early attracted the attention of navigators and was among the first subjects to be studied after the rebirth of science in Europe in the fifteenth and sixteenth centuries. These studies culminated in the work of William Gilbert, Queen Elizabeth's physician, who wrote in 1600, “Magnus magnes ipse est globus terrestris,” the earth itself is a great magnet.
Acoustically Coupled Rooms
Authors: Harris Cyril M.
Published: January 2009

Many useful engineering formulas in room acoustics can be obtained from the methods of “geometrical” acoustics which assume that sound travels as rays in a manner somewhat similar to that of light.
Light in the Eye
Authors: Mote F. A.
Published: January 2009

The most important determiner of the state of human visual sensitivity is the level of illumination to which the eye has been exposed.
Scattering Theory
Authors: Parzen G.
Published: January 2009

Because high energy electrons have become available fairly recently, the scattering theory of the Dirac equation has been only slightly developed.
Scientific Manpower
Authors: Barton Henry A.
Published: January 2009

It is characteristic of Government, as well as other enterprises of the human race, that adequate measures to meet an emergency are seldom fully taken before the emergency arises.
Spin Echoes
Authors: Hahn Erwin L.
Published: January 2009

An ensemble of nuclear magnetic moments which freely precesses in phase in a large magnetic field at a given Larmor frequency will provide a nuclear induction signal.
Thyratron Thermostat
Authors: Eubank W. R.
Published: January 2009

Systematic phase-equilibrium studies have been of great value in exploring new systems involving the components of glass, refractories, metallic alloys, portland cement, and other industrial products.
Physics in Brazil—Ways and means
Authors: Gross B.
Published: January 2009

Like its prominent representative C. M. G. Lattes, physics in Brazil is young. In the tens and twenties a considerable effort to orient the main directions of Brazilian research was made by Henrique Morize, a physicist of French origin, who became professor at the Technical College in Rio de Janeiro and director of the Astronomical Observatory; his orientation is still kept at these institutions by his successors. On a wider scale, organized research in physics started after the first faculties of science and technical research institutes came into existence. Since then it has developed at an astonishing pace in spite of many handicaps which are caused by Brazil's great distance from the principle centers of scientific and industrial production.
Sensitive
Authors: Biltz Martin
Published: January 2009

The latent image formed on exposing a photographic emulsion to light is generally believed to consist of an agglomeration of silver atoms (a minute silver crystal) formed at the site of a “sensitivity speck” or “trap.”
Physics Today⋯1950
Authors: Barton Henry A.
Published: January 2009

The American Institute of Physics has discontinued the free circulation of Physics Today to all members. Despite that fact, this issue, the very first limited to paid subscribers, will have a circulation of over 10,000. So far as we know, Physics Today has the largest circulation among physicists of any single periodical. With such support, Physics Today enters its third calendar year of life inspired to continued improvement and confident of a growing readership.
Alpha-Emission
Authors: Seaborg G. T.
Published: January 2009

The first successful application of quantum mechanics in relation to the atomic nucleus was the satisfactory explanation about 20 years ago of the dependence of the half-life for alpha-particle emission on the alpha-energy and the atomic number (and radius) of the nucleus.
Nuclear Magnetism
Authors: Weisskopf V. F.
Published: January 2009

The measurements of magnetic properties of nuclei have progressed so far that it is already possible to draw some conclusions as to the distribution of magnetism within an atomic nucleus.
Integrating Counters
Authors: Gross E. P.
Published: January 2009

A good crystal counter material must possess a low density of traps and must form large single crystals.
Mathematical Biophysics
Authors: Rapoport A.
Published: January 2009

A modification of the two-factor theory of nerve excitation is introduced in the September, 1949 issue of the Bulletin of Mathematical Biophysics.
Astrophysicists watch the Sun
Authors: Menzel Donald H. , Wyatt Catherine B.
Published: January 2009

High in the Colorado Rockies at an altitude where some fliers put on oxygen masks, observers keep daily watch on the sun with a special type of instrument. The High Altitude Observatory of Harvard University and University of Colorado, the highest permanent astronomical laboratory in the world, houses a very new type of solar telescope, the coronagraph. The coronagraph, as its name implies, records the corona, the faint outer envelope of the solar atmosphere which makes an eclipse of the sun a spectacle of awesome beauty.
Advertiser Killer
Authors: Cornog I. Clyde
Published: January 2009

This article describes a simple electronic device for protecting the radio listener from the interminable razzle-dazzle of radio advertising.
Ultrasonic Wind
Authors: Herzfeld K. F.
Published: January 2009

In strong sound fields, and particularly in ultrasonics, where one can easily produce high intensities, a flow of the medium away from the source has often been noticed—probably first by Lord Rayleigh—and is now called the ultrasonic wind or quartz wind.
Order in metallic crystals
Authors: Smoluchowski R.
Published: January 2009

To most people the beauty and harmony of crystalline form are synonymous with perfection and stability, and their metaphorical usage is indeed widespread. The curious and often skeptical scientists, however, long suspected that a more detailed study of crystals would reveal imperfections of various kinds; and the advent of modern research tools and, in particular, of x-ray diffraction methods has in fact opened a vast field of study in which changes, reactions, and imperfections in crystals are being investigated. At the same time, to be sure, the very same methods told physicists many of the why's and how's of the startling harmony and symmetry of the internal and external structure of crystals.
Thin Metal Films
Authors: Scott G. D.
Published: January 2009

The physical properties of evaporated metal films cannot in general be explained in terms of the bulk metal: it is usually necessary to assume an aggregated structure, particularly in the case of films less than 150 Angstroms in thickness.
Talent Prediction
Authors: Kruglak Haym
Published: January 2009

For the past few years there has been a growing interest in the early identification and encouragement of promising science students.
Neutrons as waves and particles
Authors: Wollan E. O. , Shull C. G.
Published: January 2009

The arrival at our present stage of understanding of atomic and nuclear structure has been greatly complicated by the fact that one's thought pattern has had to be modified with respect to everyday experience in order to gain a truer understanding of atomic phenomena. An example of this, useful for the present purpose, is the dual characterization which is associated with atomic or nuclear particles in their behavior as particles or as waves. Neutrons are of this nature, and although they are invariably referred to as particles, we know them to have the characteristics of both waves and particles. This fact makes it difficult for one to form a sensible mental picture of a neutron and somewhat in desperation we have been led to visualize it as illustrated in the accompanying caricature. This picture may be quite different from the one that you have in mind or that which might be drawn by someone else, but its chief merit is that it possesses features which describe most of the properties which we know to be associated with neutrons.
Guidance devices for the blind
Authors: Cooper Franklin S.
Published: January 2009

Freedom means many things. For the blind, one of its essential elements is independence of movement. Yet, despite the remarkable skills of some gifted individuals, the number of those who travel by themselves is only a small fraction of all the able-bodied blind. Too often, blindness means staying at home.
Stratified
Authors: Salzberg Bernard
Published: January 2009

During the past decade multilayer arrangements of films have been found increasingly useful as a means of reducing reflection from glass, and of filtering polychromatic radiation.
The insides of metals
Authors: Zapffe Carl A.
Published: January 2009

Lost in antiquity are the origins of many methods used for examining metals, but the epochal discovery of the optical microscope a few hundred years ago originated the study of metals at high magnification. In its early stages, investigation with the microscope was limited to an exploration of surfaces. This was uninstructive because the principal service of metals lies in their strength, hence, in their internal constitution. The French scientist de Réaumur in 1722 and Sweden's Swedenborg in 1734 advanced the application of the microscope somewhat by studying the surfaces of fractures of metals, which disclosed some information regarding the manner in which metals are constituted. However, the difficulty of bringing the microscope lens close to the jagged surface of a fracture discouraged, for more than two centuries, these and all later scientists from developing such an application.
Soap on Rye
Authors: Stosick A. J.
Published: January 2009

Soaps are metal salts of long chain fatty acids.
Acoustics
Authors: Fletcher Harvey
Published: January 2009

It has been my good fortune to be associated with the Board of Governors of the Institute of Physics most of the time from its organization and therefore I know the progress that has been made since the founding of the Institute. Many important things have happened during those twenty years, both in science and in our national and international affairs. Although we seem to make little or no progress in learning how to live together peaceably, these twenty years have been brilliant ones for scientific achievement.
Standards for electrical measurement
Authors: Silsbee Francis B.
Published: January 2009

Precise electrical measurements are of fundamental importance to modern science and industry. This is true not only in the communication and power fields but in many other areas where the flexibility and convenience of electrical methods have made them almost indispensable for the measurement of nonelectrical quantities. Thus, while in textbooks energy is defined simply in terms of force and length or of mass and velocity, in actual practice the heat energy of fuels and the energy output of prime movers are universally measured to high precision by electrical methods. Likewise, the basic electrical units enter into the determination of nearly all the fundamental atomic constants, as well as into daily measurements of heat, light, color, strain, acceleration, displacement, and chemical properties.
Sigma Pi Sigma
Authors: White Marsh W.
Published: January 2009

Fifth National Convention
Gaseous Electronics
Authors: Cobine J. D.
Published: January 2009

Third Annual Conference
Growing waves
Authors: Pierce J. R.
Published: January 2009

The talented or lucky physicist who discovers broad new laws escapes a good deal of the grief that comes to him who tries to work out their consequences. Certainly, Maxwell's equations and the equations of motion, relativistic or nonrelativistic, are simpler and more memorable than the organized interaction of clouds of charged particles with electromagnetic fields.
Testimony on manpower
Authors: Harrison George R.
Published: January 2009

“Senator Johnson and Member of the Committee:

“I favor the concept that all young men should be obligated to render for a certain period some form of ‘time tax’ toward national security. The problem is how to levy this tax in the way most useful to the nation. In general I support the view that, as nearly universally as possible, the time should be taken between graduation from high school and subsequent activities, since in most cases this is the least disruptive time in the career of the individual. However, in some cases the nation might better ask young men to serve at a later and less convenient time, after they have developed aptitudes which will enable them to render specialized and greater service which the nation now needs badly and will find increasingly difficult to obtain.
The Fulbright Program
Authors: Gray Dwight E.
Published: January 2009

During the academic year 1950–51, over 200 United States citizens in the general category of “lecturers and research scholars” have been pursuing educational activities of various kinds in foreign countries as a result of having received Fulbright awards. At the same time approximately an equal number of foreign nationals have been assisted by Fulbright travel grants in carrying on lecturing and research in the United States. The purpose of this article is to describe the organization and operation of the Fulbright Award Program with special emphasis on those phases which may have particular interest for physicists.
Science in the State Department
Authors: Gray Dwight E.
Published: January 2009

With the formal establishment February 6, 1951, of the Office of Science Adviser under the direction of the Under Secretary of State, official implementation may be said to have begun of the recommendations contained in “Science and Foreign Relations,” the report of the Survey Group headed by Dr. Lloyd V. Berkner. The appointment of Dr. Joseph B. Koepfli to the post of Science Adviser and chief of this office has already been announced in this journal. The intent of this article is, first, to summarize the activities which led to the establishment of a Science Office in the State Department and, second, to describe briefly the progress made thus far—both since the official date mentioned above and during the preparatory period which preceded it.
Communication theory
Authors: Pierce J. R.
Published: January 2009

The whole history of electrical communication shows an advance from an almost intuitive art of using a few specialized devices to a well-ordered understanding of satisfactorily functioning systems—an advance, in fact, from practice to theory. Practice, in the sense of cleverness with devices, of a feel for things electrical, of accumulated experience unconsciously absorbed through the pores, is not a very practical foundation for a well-developed field of technology. Rather, the most practical and valuable tool an engineer can have in any field of work is a broad and quantitative understanding of the problem with which he is dealing: in other words, a general mathematical theory of the subject. In many cases, tremendous progress has been made without any such broad understanding. However, such understanding makes work easier, cheaper and more thorough. It helps the engineer in several ways.
Crystals
Authors: Olshevsky Dimitry E.
Published: January 2009

The recent paper of John Strong on “Experimental Infrared Spectroscopy” (Physics Today, April, 1951) is an interesting contribution to the subject of useful infrared techniques. It contains some historic remarks upon which I should like to elaborate. As a summer session graduate assistant to Dr. H. M. Randall, it was my privilege to initiate, at his request, crystal growing research for infrared spectroscopy at the East Physics Laboratory of the University of Michigan in the summer of 1927. After growing some alkali halide crystals from aqueous solutions on a mercury surface, I concentrated on KC1 crystallization from the melts. A crucible was slowly lowered out of an electric furnace by a reduction gear mechanism to minimize supercooling of the melt and assure the formation of only a few crystal seeds. In spite of the crude technique, I produced a fairly clear 7 mm single crystal cube of sylvine. This proved the feasibility of the approach. However, I had to return to the University of Pittsburgh to continue my PhD work. My laboratory room in the third basement of East Physics Building was later occupied by Mr. Strong who continued this research and grew larger and clearer crystals.
High Altitude Laboratories
Authors: Korff Serge A.
Published: January 2009

In connection with a recent article on high altitude observatories (Physics Today, November, 1950), the existence of one more new station has just been brought to my attention. Last year the Bolivian government inaugurated a small observing station in Chacaltaya in Bolivia. This station is located at a geographic latitude 16 degrees, 19 minutes south and longitude 68 degrees, 10 minutes west, and at an altitude of 5490 meters above sea level.
Alphabet soup
Authors: Zemansky Mark W.
Published: January 2009

Physics is a difficult subject. It is difficult to learn and difficult to teach. There are almost four thousand members of the American Association of Physics Teachers, and possibly an equal number of teachers who are not members of the Association, whose energy and talent are devoted during part of the day to helping students learn physics for themselves. A teacher can only shorten the time and lighten the burden. In the end a textbook is used, and the student is required to study it to the extent that he can reproduce from memory a fair percentage of the laws and principles of physics, many of which are expressed in mathematical language. It is not necessary at this stage in the development of physics to apologize to a student for using mathematical symbols, but there are times when a teacher feels apologetic for some of the symbols that the student is expected to remember and reproduce.
Stalin Prize
Authors: Lane C. T.
Published: January 2009

On March 16 last the New York Times, in a dispatch from their Moscow correspondent, reported on the award of a group of “Stalin Prizes” to a number of Soviet scientists and engineers. According to the article, “an important award” went to Boris G. Lazarev for “a new method of enrichment of helium with light isotopes”.
Recent developments in physics abstracting
Authors: Gray Dwight E.
Published: January 2009

Among the more venerable medical jokes is that one with the punch line, “The operation was a success but the patient died”. In the case of ills of organizations, an approximate analogue to this situation occurs when a survey made by a sub-committee or study group with a view to remedying some society malady produces a list of praiseworthy recommendations none of which is ever put into effect. The patient may not die under these circumstances but neither does he get any better. It will be recalled that a year or two ago the American Physical Society and the American Institute of Physics jointly sponsored a study of physics abstracting which was supported under a contract with the Office of Naval Research. This study developed certain information as a result of which the Joint Committee on Science Abstracts of the Physical Society and the Institute made a series of recommendations. Both the results of the study and the recommendations have been reported previously in the American Journal of Physics (18, 417–424, October, 1950). The purpose of this article is to discuss the implementation of these recommendations that has been accomplished to date or is under way, with the hope of demonstrating that in this case the patient has shown at least some degree of improvement following, as it were, consultation and an exploratory operation.
Activated Reservist
Authors: Kinmonth Raymond A.
Published: January 2009

From various articles which I have read, I have been led to believe that this country faces a shortage of trained personnel in the scientific professions. I believed this to include college graduates along with the doctorates and post doctorates, the general scientist along with the highly specialized. Apparently this is not true for many of us who at present hold only the BS or the BA degrees.
Identities and Belonging: A Study of Somali Refugee and Asylum Seekers Living in the UK and Denmark
Authors: Valentine Gill , Sporton Deborah , Nielsen Katrine Bang
Published: January 2009

Drawing on empirical research with young refugees and asylum seekers (aged 11–18) now living in Sheffield, UK, and Aarhus, Denmark, respectively, this paper explores some of the relationships between identity, belonging, and place. We begin by reflecting on the young people's sense of identity as Somali in the context of periods of forced and voluntary mobility. We then consider what it means to be Muslim in the context of the different communities of practice in Aarhus and Sheffield. Finally, we consider the extent to which the interviewees self-identify as Danish or British. In reflecting on these different dimensions of identification and belonging, we conclude by highlighting the importance of being ‘in place’ for attachment and security, and identify implications of the findings for integration and cohesion policies.
Biodiversity of diatom assemblages in a Mediterranean semiarid stream: implications for conservation
Authors: Ros M. Dolores , Marín-Murcia José Pedro , Aboal Marina
Published: January 2009

Many semiarid streams are threatened both by human demands and climatic effects (global warming), but little is known about their algal biodiversity and their conservation value, especially in Mediterranean areas. The aim of the present study was to evaluate annual changes in the structure and species richness of diatom communities in runs and pools of an oligohaline, semiarid stream in south-eastern Spain, and their relationship with nutrients and hydrology. The pool substrate was covered most of the time by a yellow-brown coat, mainly composed of diatoms and a few cyanophytes (Leptolyngbya). In the runs, cyanophytes were dominant (Rivularia) and diatoms occurred as epiphytes. The diversity of these diatom assemblages was high, particularly in the pools. Some species were present throughout the year, whereas others showed a bimodal growth pattern. Maximum biomasses were reached in summer in the pools and in autumn in the runs, when levels of phosphorus increased as a result of flooding. Species richness and diversity were correlated with hydrology and sulfate concentrations, whereas biomass (as chlorophyll a and ash-free dry weight) was associated with variations in temperature, conductivity and ammonium. These semiarid streams are refuges of biodiversity, representing habitats reliant on cycles of drought and floods, which should be considered in proposals for their conservation.
Infection risk and intrauterine devices
Authors: MARTÍNEZ FRANCISCA , LÓPEZ‐ARREGUI EDUARDO
Published: January 2009

For most women, intrauterine contraceptive devices (IUCD) are a safe option. Upper genital tract infections (pelvic inflammatory disease, PID) occur when pathogenic microorganisms ascend from the cervix and invade the endometrium and the fallopian tubes, causing an inflammatory reaction. Evidence‐based recommendations regarding intrauterine contraception and risk of infection were presented at the Congress of the European Society of Contraception, in Prague, 2008: A clinical history (including sexual history) should be taken as part of the routine assessment for intrauterine contraception to identify women at high risk of sexually transmitted infections (STI); if appropriate a test should be offered; if symptoms or signs are present, appropriate diagnostic tests should be done, results awaited, necessary treatment completed, and IUCD insertion postponed until resolution. Prophylactic antibiotics are not recommended (evidence level II‐3). STI screening is not routinely recommended. PID among IUCD users is most strongly related to the insertion process and to the background risk of STI (evidence level II‐2). Conditions which represent an unacceptable health risk if an IUCD is inserted (WHO Medical Eligibility Criteria, MEC, Categories 3–4) are current PID, current purulent cervicitis, chlamydial or gonorrheal infection. For continuation as well as initiation, WHO MEC categories 3–4 are allotted to women with known pelvic tuberculosis, puerperal sepsis and septic abortion.