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Sample records for accelerated expanding universe

  1. Thermodynamics of an accelerated expanding universe

    SciTech Connect

    Wang Bin; Gong Yungui; Abdalla, Elcio

    2006-10-15

    We investigate the laws of thermodynamics in an accelerating universe driven by dark energy with a time-dependent equation of state. In the case we consider that the physically relevant part of the Universe is that enveloped by the dynamical apparent horizon, we have shown that both the first law and second law of thermodynamics are satisfied. On the other hand, if the boundary of the Universe is considered to be the cosmological event horizon the thermodynamical description based on the definitions of boundary entropy and temperature breaks down. No parameter redefinition can rescue the thermodynamics laws from such a fate, rendering the cosmological event horizon unphysical from the point of view of the laws of thermodynamics.

  2. Focusing of geodesic congruences in an accelerated expanding Universe

    SciTech Connect

    Albareti, F.D.; Cembranos, J.A.R.; Cruz-Dombriz, A. de la E-mail: cembra@fis.ucm.es

    2012-12-01

    We study the accelerated expansion of the Universe through its consequences on a congruence of geodesics. We make use of the Raychaudhuri equation which describes the evolution of the expansion rate for a congruence of timelike or null geodesics. In particular, we focus on the space-time geometry contribution to this equation. By straightforward calculation from the metric of a Robertson-Walker cosmological model, it follows that in an accelerated expanding Universe the space-time contribution to the Raychaudhuri equation is positive for the fundamental congruence, favoring a non-focusing of the congruence of geodesics. However, the accelerated expansion of the present Universe does not imply a tendency of the fundamental congruence to diverge. It is shown that this is in fact the case for certain congruences of timelike geodesics without vorticity. Therefore, the focusing of geodesics remains feasible in an accelerated expanding Universe. Furthermore, a negative contribution to the Raychaudhuri equation from space-time geometry which is usually interpreted as the manifestation of the attractive character of gravity is restored in an accelerated expanding Robertson-Walker space-time at high speeds.

  3. Expanding Universe

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    A universe that expands with time. Although the possibility had been raised earlier through theoretical work carried out by Willem de Sitter (1872-1934), Aleksandr Friedmann (1888-1925), and the Abbé Georges Lemaître (1894-1966), that our universe is expanding was first demonstrated observationally in 1929 by Edwin P Hubble (1889-1953), through his measurements of the redshifts in the spectra of ...

  4. Expanding Universe

    NASA Astrophysics Data System (ADS)

    Schrödinger, E.

    2011-02-01

    Preface; Part I. The de Sitter Universe: 1. Synthetic construction; 2. The reduced model: geodesics; 3. The elliptic interpretation; 4. The static frame; 5. The determination of parallaxes; 6. The Lemaître-Robertson frame; Part II. The Theory of Geodesics: 7. On null geodesics; i. Determination of the parameter for null lines in special cases; ii. Frequency shift; 8. Free particles and light rays in general expanding spaces, flat or hyperspherical; i. Flat spaces; ii. Spherical spaces; iii. The red shift for spherical spaces; Part III. Waves in General Riemannian Space-Time: 9. The nature of our approximation; 10. The Hamilton-Jacobi theory in a gravitational field; 11. Procuring approximate solutions of the Hamilton-Jacobi equation from wave theory; Part IV. Waves in an Expanding Universe: 12. General considerations; 13. Proper vibrations and wave parcels; Bibliography.

  5. What Expands in an Expanding Universe?

    PubMed

    Pacheco, José A De Freitas

    2015-01-01

    In the present investigation, the possible effects of the expansion of the Universe on systems bonded either by gravitational or electromagnetic forces, are reconsidered. It will be shown that the acceleration (positive or negative) of the expanding background, is the determinant factor affecting planetary orbits and atomic sizes. In the presently accepted cosmology (ΛCDM) all bonded systems are expanding at a decreasing rate that tends to be zero as the universe enters in a de Sitter phase. It is worth mentioning that the estimated expansion rates are rather small and they can be neglected for all practical purposes. PMID:26628035

  6. What Expands in an Expanding Universe?

    PubMed

    Pacheco, José A De Freitas

    2015-01-01

    In the present investigation, the possible effects of the expansion of the Universe on systems bonded either by gravitational or electromagnetic forces, are reconsidered. It will be shown that the acceleration (positive or negative) of the expanding background, is the determinant factor affecting planetary orbits and atomic sizes. In the presently accepted cosmology (ΛCDM) all bonded systems are expanding at a decreasing rate that tends to be zero as the universe enters in a de Sitter phase. It is worth mentioning that the estimated expansion rates are rather small and they can be neglected for all practical purposes.

  7. Discovering the Expanding Universe

    NASA Astrophysics Data System (ADS)

    Nussbaumer, Harry; Bieri, Lydia; Sandage, Foreword by Allan

    2009-03-01

    Acknowledgments; Foreword; 1. Introduction; 2. Cosmological concepts at the end of the Middle Ages; 3. Nebulae as a new astronomical phenomenon; 4. On the construction of the Heavens; 5. Island universes turn into astronomical facts: a universe of galaxies; 6. The early cosmology of Einstein and de Sitter; 7. The dynamical universe of Friedmann; 8. Redshifts: how to reconcile Slipher and de Sitter?; 9. Lemaître discovers the expanding universe; 10. Hubble's contribution of 1929; 11. The breakthrough for the expanding universe; 12. Hubble's anger about de Sitter; 13. Robertson and Tolman join the game; 14. The Einstein-de Sitter universe; 15. Are Sun and Earth older than the universe?; 16. In search of alternative tracks; 17. The seed for the Big Bang; 18. Summary and Postscript; Appendix; References; Index.

  8. The Artful Universe Expanded

    NASA Astrophysics Data System (ADS)

    Barrow, John D.

    2005-07-01

    Our love of art, writes John Barrow, is the end product of millions of years of evolution. How we react to a beautiful painting or symphony draws upon instincts laid down long before humans existed. Now, in this enhanced edition of the highly popular The Artful Universe , Barrow further explores the close ties between our aesthetic appreciation and the basic nature of the Universe. Barrow argues that the laws of the Universe have imprinted themselves upon our thoughts and actions in subtle and unexpected ways. Why do we like certain types of art or music? What games and puzzles do we find challenging? Why do so many myths and legends have common elements? In this eclectic and entertaining survey, Barrow answers these questions and more as he explains how the landscape of the Universe has influenced the development of philosophy and mythology, and how millions of years of evolutionary history have fashioned our attraction to certain patterns of sound and color. Barrow casts the story of human creativity and thought in a fascinating light, considering such diverse topics as our instinct for language, the origins and uses of color in nature, why we divide time into intervals as we do, the sources of our appreciation of landscape painting, and whether computer-generated fractal art is really art. Drawing on a wide variety of examples, from the theological questions raised by St. Augustine and C.S. Lewis to the relationship between the pure math of Pythagoras and the music of the Beatles, The Artful Universe Expanded covers new ground and enters a wide-ranging debate about the meaning and significance of the links between art and science.

  9. The Expanding Universe

    NASA Astrophysics Data System (ADS)

    Heacox, William D.

    2015-11-01

    Introducing the Universe; Part I. Conceptual Foundations: 1. Newtonian cosmology; 2. General relativity; 3. Relativistic cosmology; Part II. General Relativity: 4. General covariance; 5. Equivalence principle; 6. Space-time curvature; 7. Einstein field equations of gravitation; Part III. Universal Expansion: 8. Cosmological field equations; 9. Cosmography; 10. Expansion dynamics; Part IV. Expansion Models: 11. Radiation; 12. Matter; 13. Dark energy; 14. Observational constraints; 15. Concordance cosmological model; Part V. Expansion History: 16. Particle era; 17. Plasma era; 18. Galaxy era; 19. Afterword: the new modern cosmology; Part VI: Appendices; Bibliography; Index.

  10. Entropy in an expanding universe.

    PubMed

    Frautschi, S

    1982-08-13

    The question of how the observed evolution of organized structures from initial chaos in the expanding universe can be reconciled with the laws of statistical mechanics is studied, with emphasis on effects of the expansion and gravity. Some major sources of entropy increase are listed. An expanding "causal" region is defined in which the entropy, though increasing, tends to fall further and further behind its maximum possible value, thus allowing for the development of order. The related questions of whether entropy will continue increasing without limit in the future, and whether such increase in the form of Hawking radiation or radiation from positronium might enable life to maintain itself permanently, are considered. Attempts to find a scheme for preserving life based on solid structures fail because events such as quantum tunneling recurrently disorganize matter on a very long but fixed time scale, whereas all energy sources slow down progressively in an expanding universe. However, there remains hope that other modes of life capable of maintaining themselves permanently can be found.

  11. Supernovae and the Accelerating Universe

    NASA Technical Reports Server (NTRS)

    Wood, H. John

    2003-01-01

    Orbiting high above the turbulence of the earth's atmosphere, the Hubble Space Telescope (HST) has provided breathtaking views of astronomical objects never before seen in such detail. The steady diffraction-limited images allow this medium-size telescope to reach faint galaxies of 30th stellar magnitude. Some of these galaxies are seen as early as 2 billion years after the Big Bang in a 15 billion year old universe. Up until recently, astronomers assumed that all of the laws of physics and astronomy applied back then as they do today. Now, using the discovery that certain supernovae are standard candles, astronomers have found that the universe is expanding faster today than it was back then: the universe is accelerating in its expansion.

  12. Expanding the Universe of Education.

    ERIC Educational Resources Information Center

    Parsons, Elizabeth

    1996-01-01

    Definitions of "education" and "rural" are debunked and expanded. The three major tasks of rural education are educating people to understand their own needs, the unavoidable changes that will transform rural Australia within their lifetimes, and the range of technologies that can enhance their well-being. Presents a strategy for educating…

  13. An Expanding Universe in the Classroom.

    ERIC Educational Resources Information Center

    Chandler, David

    1991-01-01

    Two computer-generated star charts that can be used as overlay transparencies to show an expanding universe are presented. Directions on how to use the star charts to determine the Hubble constant and the age of the universe are provided. (KR)

  14. Distant Supernovae Indicate Ever-Expanding Universe

    NASA Astrophysics Data System (ADS)

    1998-12-01

    ESO Astronomers Contribute towards Resolution of Cosmic Puzzle Since the discovery of the expansion of the Universe by American astronomer Edwin Hubble in the 1920's, by measurement of galaxy velocities, astronomers have tried to learn how this expansion changes with time. Until now, most scientists have been considering two possibilities: the expansion rate is slowing down and will ultimately either come to a halt - whereafter the Universe would start to contract, or it will continue to expand forever. However, new studies by two independent research teams, based on observations of exploding stars ( supernovae ) by ESO astronomers [1] with astronomical telescopes at the La Silla Observatory as well as those of their colleagues at other institutions, appear to show that the expansion of the Universe is accelerating . The results take the discovery of the cosmological expansion one step further and challenge recent models of the Universe. If the new measurements are indeed correct, they show that the elusive "cosmological constant" , as proposed by Albert Einstein , contributes significantly to the evolution of the Universe. The existence of a non-zero cosmological constant implies that a repulsive force, counter-acting gravity, currently dominates the universal expansion , and consequently leads to an ever-expanding Universe. This new research is being named as the "Breakthrough of the Year" by the renowned US science journal Science in the December 18, 1998, issue. A Press Release is published by the journal on this occasion. "Fundamental Parameters" of the Universe Three fundamental parameters govern all cosmological models based on the theory of General Relativity. They are 1. the current expansion rate as described by Hubble's constant , i.e. the proportionality factor between expansion velocity and distance 2. the average matter density in the Universe, and 3. the amount of "other energy" present in space. From the measured values of these fundamental

  15. The Accelerating Universe

    SciTech Connect

    Blandford, Roger

    2013-05-15

    From keV electrons in terrestrial aurorae to Ultra High Energy Cosmic Rays from unidentified "Zevatrons", the cosmos shows a plutocratic proclivity to concentrate energy in a tiny minority of suprathermal particles. The mechanisms involved can be traced back to the ideas of Faraday, Fermi and Alfvén though we are learning that the details are idiosyncratic to the many environments that we have observed and that much can be learned from comparing and contrasting particle acceleration in laboratory and diverse astronomical locations. It will be argued that new mechanisms are required to account for recent observations of galactic nuclei, pulsar wind nebulae and interplanetary, interstellar and intergalactic media and some candidates will be discussed.

  16. The accelerating universe and dark energy

    NASA Astrophysics Data System (ADS)

    Baltay, Charles

    2014-05-01

    The recent discovery by Riess et al.1 and Perlmutter et al.2 that the expansion of the universe is accelerating is one of the most significant discoveries in cosmology in the last few decades. To explain this acceleration a mysterious new component of the universe, dark energy, was hypothesized. Using general relativity (GR), the measured rate of acceleration translates to the present understanding that the baryonic matter, of which the familiar world is made of, is a mere 4% of the total mass-energy of the universe, with nonbaryonic dark matter making up 24% and dark energy making up the majority 72%. Dark matter, by definition, has attractive gravity, and even though we presently do not know what it is, it could be made of the next heavy particles discovered by particle physicists. Dark energy, however, is much more mysterious, in that even though we do not know what it is, it must have some kind of repulsive gravity and negative pressure, very unusual properties that are not part of the present understanding of physics. Investigating the nature of dark energy is therefore one of the most important areas of cosmology. In this review, the cosmology of an expanding universe, based on GR, is discussed. The methods of studying the acceleration of the universe, and the nature of dark energy, are presented. A large amount of experimentation on this topic has taken place in the decade since the discovery of the acceleration. These are discussed and the present state of knowledge of the cosmological parameters is summarized in Table 7 below. A vigorous program to further these studies is under way. These are presented and the expected results are summarized in Table 10 below. The hope is that at the end of this program, it would be possible to tell whether dark energy is due to Einstein's cosmological constant or is some other new constituent of the universe, or alternately the apparent acceleration is due to some modification of GR.

  17. Black holes in an expanding universe.

    PubMed

    Gibbons, Gary W; Maeda, Kei-ichi

    2010-04-01

    An exact solution representing black holes in an expanding universe is found. The black holes are maximally charged and the universe is expanding with arbitrary equation of state (P = w rho with -1 < or = for all w < or = 1). It is an exact solution of the Einstein-scalar-Maxwell system, in which we have two Maxwell-type U(1) fields coupled to the scalar field. The potential of the scalar field is an exponential. We find a regular horizon, which depends on one parameter [the ratio of the energy density of U(1) fields to that of the scalar field]. The horizon is static because of the balance on the horizon between gravitational attractive force and U(1) repulsive force acting on the scalar field. We also calculate the black hole temperature.

  18. Entangling power of an expanding universe

    SciTech Connect

    Steeg, Greg Ver; Menicucci, Nicolas C.

    2009-02-15

    We show that entanglement can be used to detect spacetime curvature. Quantum fields in the Minkowski vacuum are entangled with respect to local field modes. This entanglement can be swapped to spatially separated quantum systems using standard local couplings. A single, inertial field detector in the exponentially expanding (de Sitter) vacuum responds as if it were bathed in thermal radiation in a Minkowski universe. We show that using two inertial detectors, interactions with the field in the thermal case will entangle certain detector pairs that would not become entangled in the corresponding de Sitter case. The two universes can thus be distinguished by their entangling power.

  19. Is the Universe's Acceleration Eternal?

    NASA Astrophysics Data System (ADS)

    Bean, Rachel; Magueijo, Joao; Barrow, John

    2002-12-01

    We present a new interpretation of recent observations suggesting that the expansion of the Universe has recently started to accelerate. First we introduce a cosmological model with a minimally coupled quintessence field driven by a potential motivated by M-theory. We find that late-time acceleration does not have to lead to the usual predictions of perpetual acceleration. The model allows another broad class of scenarios in which today's acceleration is a transient phenomenon which is succeeded by a return to matter domination and decelerating expansion. Quintessence scenarios provide a simple explanation for the observed acceleration of the Universe. Yet, explaining why acceleration did not start a long time ago remains a challenge. The idea that the transition from radiation to matter domination played a dynamical role in triggering acceleration has been put forward in various guises. We, secondly, propose a simple dilaton-derived quintessence model in which temporary vacuum domination is naturally triggered by the radiation to matter transition. In this model Einstein's gravity is preserved but quintessence couples non-minimally to the cold dark matter, but not to "visible" matter. Such couplings have been attributed to the dilaton in the low-energy limit of string theory beyond tree level.

  20. Acceleration of black hole universe

    NASA Astrophysics Data System (ADS)

    Zhang, T. X.; Frederick, C.

    2014-01-01

    Recently, Zhang slightly modified the standard big bang theory and developed a new cosmological model called black hole universe, which is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain all observations of the universe. Previous studies accounted for the origin, structure, evolution, expansion, and cosmic microwave background radiation of the black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This paper investigates acceleration of the black hole universe and provides an alternative explanation for the redshift and luminosity distance measurements of type Ia supernovae. The results indicate that the black hole universe accelerates its expansion when it accretes the ambient matter in an increasing rate. In other words, i.e., when the second-order derivative of the mass of the black hole universe with respect to the time is positive . For a constant deceleration parameter , we can perfectly explain the type Ia supernova measurements with the reduced chi-square to be very close to unity, χ red˜1.0012. The expansion and acceleration of black hole universe are driven by external energy.

  1. Quasi-gravitational Effect in the Accelerating Universe

    NASA Astrophysics Data System (ADS)

    Harutyunian, H. A.

    2016-09-01

    The possibility of measuring of the accelerated expansion rate at any point of our Universe is considered. It is argued that as the only reference frame in the Universe expanding with acceleration can serve the cosmological horizon - the most distant sphere belonging the observable Universe. All the points of this sphere represent the initial point coincided with the observer's local point at the beginning of time. And at the present the observer moves away from all that points. Simple calculations show that the acceleration of the observer with respect to the cosmological horizon is very small and numerically equal to the Pioneers' anomalous acceleration.

  2. Painful Na-channelopathies: an expanding universe.

    PubMed

    Waxman, Stephen G

    2013-07-01

    The universe of painful Na-channelopathies--human disorders caused by mutations in voltage-gated sodium channels--has recently expanded in three dimensions. We now know that mutations of sodium channels cause not only rare genetic 'model disorders' such as inherited erythromelalgia and channelopathy-associated insensitivity to pain but also common painful neuropathies. We have learned that mutations of NaV1.8, as well as mutations of NaV1.7, can cause painful Na-channelopathies. Moreover, recent studies combining atomic level structural models and pharmacogenomics suggest that the goal of genomically guided pain therapy may not be unrealistic.

  3. The Hubble Constant and the Expanding Universe

    NASA Astrophysics Data System (ADS)

    Freedman, Wendy

    2003-01-01

    In 1929 Edwin Hubble proved that our universe is expanding by showing that the farther a galaxy is from us, the faster it is speeding away into space. This velocity-distance relation came to be called Hubble's law, and the value that describes the rate of expansion is known as the Hubble constant, or H0 . Like the speed of light, H0 is a fundamental constant, and it is a key parameter needed to estimate both the age and size of the universe. Since the late 1950s astronomers have been arguing for an H0 value between 50 to 100 kilometers per second per megaparsec, a lack of precision that produced an unacceptably wide range of ages for the universe—anywhere from 10 to 20 billion years. Using the Hubble Space Telescope, Freedman and her colleagues measured H0 to an unprecedented level of accuracy, deriving a value of 72, with an uncertainty of 10 percent—a milestone achievement in cosmology. The new result suggests that our universe is about 13 billion years old, give or take a billion years, and it's a value that sits comfortably alongside the 12 billion years estimated for the age of the oldest stars.

  4. The expanding universe of p53 targets.

    PubMed

    Menendez, Daniel; Inga, Alberto; Resnick, Michael A

    2009-10-01

    The p53 tumour suppressor is modified through mutation or changes in expression in most cancers, leading to the altered regulation of hundreds of genes that are directly influenced by this sequence-specific transcription factor. Central to the p53 master regulatory network are the target response element (RE) sequences. The extent of p53 transactivation and transcriptional repression is influenced by many factors, including p53 levels, cofactors and the specific RE sequences, all of which contribute to the role that p53 has in the aetiology of cancer. This Review describes the identification and functionality of REs and highlights the inclusion of non-canonical REs that expand the universe of genes and regulation mechanisms in the p53 tumour suppressor network.

  5. Gravitational wave memory in an expanding universe

    NASA Astrophysics Data System (ADS)

    Tolish, Alexander; Wald, Robert

    2016-03-01

    We investigate the gravitational wave memory effect in an expanding FLRW spacetime. We find that if the gravitational field is decomposed into gauge-invariant scalar, vector, and tensor modes after the fashion of Bardeen, only the tensor mode gives rise to memory, and this memory can be calculated using the retarded Green's function associated with the tensor wave equation. If locally similar radiation source events occur on flat and FLRW backgrounds, we find that the resulting memories will differ only by a redshift factor, and we explore whether or not this factor depends on the expansion history of the FLRW universe. We compare our results to related work by Bieri, Garfinkle, and Yau.

  6. Henry Norris Russell and the Expanding Universe

    NASA Astrophysics Data System (ADS)

    DeVorkin, D.

    2013-04-01

    Henry Norris Russell, one of the most influential American astronomers of the first half of the 20th Century, had a special place in his heart for the Lowell Observatory. Although privately critical of the founder for his pronouncements about life on Mars and the superiority of the Mars Hill observing site, he always supported the Observatory in public and professional circles. He staunchly supported Tombaugh's detection of a planet as leading from Lowell's prediction, and always promoted V. M. Slipher's spectroscopic investigations of planetary and stellar phenomena. But how did he react to Slipher's puzzling detection of the extreme radial velocities of spiral nebulae starting in 1912, and how did he regard the extension and interpretation of those observations by Hubble and others in following decades? Here we describe the arc of Russell's reactions, dating from Slipher's first detection, as an indicator of how mainstream stellar astronomers reacted to the concept of an expanding universe.

  7. Historical Notes on the Expanding Universe

    NASA Technical Reports Server (NTRS)

    Way, Michael J.; Belenkyi, Ari; Nussbaumer, Harry; Peacock, John

    2014-01-01

    The article Measuring the Hubble constant by Mario Livio and Adam Riess (Physics Today, October 2013, page 41) reviewed studies of the expanding universe from the 1920s to the present. Although the history of the subject underwent considerable compression to fit the length of a magazine article, we think it may leave a misleading impression of some of the key steps to our current understanding. We therefore offer the following clarifications. Most significantly, papers by Arthur Eddington and by Willem de Sitter in 1930, who successfully promoted Georges Lematres 1927 article for the Scientific Society of Brussels, effected a paradigm shift in interpretation of extragalactic redshifts in 1930. Before then, the astronomical community was generally unaware of the existence of nonstatic cosmological solutions and did not broadly appreciate that redshifts could be thought of locally as Doppler shifts in an expanding matter distribution. Certainly, in 1929 Edwin Hubble referred only to the de Sitter solution of 1917. At the time, the relation between distance and redshift predicted in that model was generally seen purely as a manifestation of static spacetime curvature.

  8. BOOK REVIEW: The Artful Universe Expanded

    NASA Astrophysics Data System (ADS)

    Bassett, B. A.

    2005-07-01

    The cosmos is an awfully big place and there is no better guide to its vast expanse and fascinating nooks and crannies than John Barrow. A professor of mathematical sciences at Cambridge University, Barrow embodies that rare combination of highly polished writer and expert scientist. His deft touch brings together the disparate threads of human knowledge and weaves them into a tapestry as rich and interesting for the expert as it is for the layperson. The Artful Universe Expanded is an updated edition of this popular book first published in 1995. It explores the deeply profound manner in which natural law and the nature of the cosmos have moulded and shaped us, our cultures and the very form of our arts and music—a new type of `cosmic' anthropology. The main themes Barrow chooses for revealing this new anthropology are the subjects of evolution, the size of things, the heavens and the nature of music. The book is a large, eclectic repository of knowledge often unavailable to the layperson,\\endcolumn hidden in esoteric libraries around the world. It rivals The Da Vinci Code for entertainment value and insights, but this time it is Nature’s code that is revealed. It is rare indeed to find common threads drawn through topics as diverse as The Beetles, Bach and Beethoven or between Jackson Pollock, the Aztecs, Kant, Picasso, Byzantine mosaics, uranium-235 and the helix nebula. Barrow unerringly binds them together, presenting them in a stimulating, conversational style that belies the amount of time that must have gone into researching this book. Dip into it at random, or read it from cover to cover, but do read it. The Artful Universe Expanded is an entertaining antidote to the oft-lamented pressures to know more and more about less and less and the apparently inexorable march of specialization. On reading this book one can, for a short time at least, hold in one’s mind a vision that unifies science, art and culture and glimpse a universal tapestry of great

  9. Optical cavity resonator in an expanding universe

    NASA Astrophysics Data System (ADS)

    Kopeikin, Sergei M.

    2015-02-01

    We study the cosmological evolution of frequency of a standing electromagnetic wave in a resonant optical cavity placed to the expanding manifold described by the Robertson-Walker metric. Because of the Einstein principle of equivalence (EEP), one can find a local coordinate system (a local freely falling frame), in which spacetime is locally Minkowskian. However, due to the conformal nature of the Robertson-Walker metric the conventional transformation to the local inertial coordinates introduces ambiguity in the physical interpretation of the local time coordinate, . Therefore, contrary to a common-sense expectation, a straightforward implementation of EEP alone does not allow us to unambiguously decide whether atomic clocks based on quantum transitions of atoms, ticks at the same rate as the clocks based on electromagnetic modes of a cavity. To resolve this ambiguity we have to analyse the cavity rigidity and the oscillation of its electromagnetic modes in an expanding universe by employing the full machinery of the Maxwell equations irrespectively of the underlying theory of gravity. We proceed in this way and found out that the size of the cavity and the electromagnetic frequency experience an adiabatic drift in conformal (unphysical) coordinates as the universe expands in accordance with the Hubble law. We set up the oscillation equation for the resonant electromagnetic modes, solve it by the WKB approximation, and reduce the coordinate-dependent quantities to their counterparts measured by a local observer who counts time with atomic clock. The solution shows that there is a perfect mutual cancellation of the adiabatic drift of cavity's frequency by space transformation to local coordinates and the time counted by the clocks based on electromagnetic modes of cavity has the same rate as that of atomic clocks. We conclude that if general relativity is correct and the local expansion of space is isotropic there should be no cosmological drift of frequency of a

  10. The expanding universe of noncoding RNAs.

    PubMed

    Hannon, G J; Rivas, F V; Murchison, E P; Steitz, J A

    2006-01-01

    The 71st Cold Spring Harbor Symposium on Quantitative Biology celebrated the numerous and expanding roles of regulatory RNAs in systems ranging from bacteria to mammals. It was clearly evident that noncoding RNAs are undergoing a renaissance, with reports of their involvement in nearly every cellular process. Previously known classes of longer noncoding RNAs were shown to function by every possible means-acting catalytically, sensing physiological states through adoption of complex secondary and tertiary structures, or using their primary sequences for recognition of target sites. The many recently discovered classes of small noncoding RNAs, generally less than 35 nucleotides in length, most often exert their effects by guiding regulatory complexes to targets via base-pairing. With the ability to analyze the RNA products of the genome in ever greater depth, it has become clear that the universe of noncoding RNAs may extend far beyond the boundaries we had previously imagined. Thus, as much as the Symposium highlighted exciting progress in the field, it also revealed how much farther we must go to understand fully the biological impact of noncoding RNAs.

  11. The expanding universe of prion diseases.

    PubMed

    Watts, Joel C; Balachandran, Aru; Westaway, David

    2006-03-01

    Prions cause fatal and transmissible neurodegenerative disease. These etiological infectious agents are formed in greater part from a misfolded cell-surface protein called PrP(C). Several mammalian species are affected by the diseases, and in the case of "mad cow disease" (BSE) the agent has a tropism for humans, with negative consequences for agribusiness and public health. Unfortunately, the known universe of prion diseases is expanding. At least four novel prion diseases--including human diseases variant Creutzfeldt-Jakob disease (vCJD) and sporadic fatal insomnia (sFI), bovine amyloidotic spongiform encephalopathy (BASE), and Nor98 of sheep--have been identified in the last ten years, and chronic wasting disease (CWD) of North American deer (Odocoileus Specis) and Rocky Mountain elk (Cervus elaphus nelsoni) is undergoing a dramatic spread across North America. While amplification (BSE) and dissemination (CWD, commercial sourcing of cervids from the wild and movement of farmed elk) can be attributed to human activity, the origins of emergent prion diseases cannot always be laid at the door of humankind. Instead, the continued appearance of new outbreaks in the form of "sporadic" disease may be an inevitable outcome in a situation where the replicating pathogen is host-encoded.

  12. Tachyonic resonance preheating in an expanding universe

    SciTech Connect

    Abolhasani, Ali Akbar; Firouzjahi, Hassan; Sheikh-Jabbari, M. M.

    2010-02-15

    In this paper the tachyonic resonance preheating generated from the bosonic trilinear {phi}{chi}{sup 2} interactions in an expanding universe is studied. In {lambda}{phi}{sup 4}/4 inflationary model the trilinear interaction, in contrast to the four-legs {phi}{sup 2{chi}2}, breaks the conformal symmetry explicitly and the resonant source term becomes nonperiodic, making the Floquet theorem inapplicable. We find that the occupation number of the produced {chi} particles has a nonlinear exponential growth with exponent {approx}x{sup 3/2}, where x is the conformal time. This should be contrasted with preheating from a periodic resonant source arising, for example, from the four-legs {phi}{sup 2{chi}2} interaction, where the occupation number has a linear exponential growth. We present an analytic method to compute the interference term coming from phases accumulated in nontachyonic scattering regions and show that the effects of the interference term cause ripples on x{sup 3/2} curve, a result which is confirmed by numerical analysis. Studying the effects of backreaction of the {chi} particles, we show that tachyonic resonance preheating in our model can last long enough to transfer most of the energy from the background inflation field {phi}, providing an efficient model for preheating in the chaotic inflation models.

  13. The expanding universe of prion diseases.

    PubMed

    Watts, Joel C; Balachandran, Aru; Westaway, David

    2006-03-01

    Prions cause fatal and transmissible neurodegenerative disease. These etiological infectious agents are formed in greater part from a misfolded cell-surface protein called PrP(C). Several mammalian species are affected by the diseases, and in the case of "mad cow disease" (BSE) the agent has a tropism for humans, with negative consequences for agribusiness and public health. Unfortunately, the known universe of prion diseases is expanding. At least four novel prion diseases--including human diseases variant Creutzfeldt-Jakob disease (vCJD) and sporadic fatal insomnia (sFI), bovine amyloidotic spongiform encephalopathy (BASE), and Nor98 of sheep--have been identified in the last ten years, and chronic wasting disease (CWD) of North American deer (Odocoileus Specis) and Rocky Mountain elk (Cervus elaphus nelsoni) is undergoing a dramatic spread across North America. While amplification (BSE) and dissemination (CWD, commercial sourcing of cervids from the wild and movement of farmed elk) can be attributed to human activity, the origins of emergent prion diseases cannot always be laid at the door of humankind. Instead, the continued appearance of new outbreaks in the form of "sporadic" disease may be an inevitable outcome in a situation where the replicating pathogen is host-encoded. PMID:16609731

  14. Evolution of gravitational orbits in the expanding universe

    SciTech Connect

    Sereno, Mauro; Jetzer, Philippe

    2007-03-15

    The gravitational action of the smooth energy-matter components filling in the universe can affect the orbit of a planetary system. Changes are related to the acceleration of the cosmological scale size R. In a universe with significant dark matter, a gravitational system expands or contracts according to the amount and equation of state of the dark energy. At present time, the Solar System, according to the {lambda}CDM scenario emerging from observational cosmology, should be expanding if we consider only the effect of the cosmological background. Its fate is determined by the equation of state of the dark energy alone. The mean motion and periastron precession of a planet are directly sensitive to Re/R, whereas variations with time in the semimajor axis and eccentricity are related to its time variation. Actual bounds on the cosmological deceleration parameters q{sub 0} from accurate astrometric data of perihelion precession and changes in the third Kepler's law in the Solar System fall short of 10 orders of magnitude with respect to estimates from observational cosmology. Future radio-ranging measurements of outer planets could improve actual bounds by 5 orders of magnitude.

  15. Evolution of gravitational orbits in the expanding universe

    NASA Astrophysics Data System (ADS)

    Sereno, Mauro; Jetzer, Philippe

    2007-03-01

    The gravitational action of the smooth energy-matter components filling in the universe can affect the orbit of a planetary system. Changes are related to the acceleration of the cosmological scale size R. In a universe with significant dark matter, a gravitational system expands or contracts according to the amount and equation of state of the dark energy. At present time, the Solar System, according to the ΛCDM scenario emerging from observational cosmology, should be expanding if we consider only the effect of the cosmological background. Its fate is determined by the equation of state of the dark energy alone. The mean motion and periastron precession of a planet are directly sensitive to R¨/R, whereas variations with time in the semimajor axis and eccentricity are related to its time variation. Actual bounds on the cosmological deceleration parameters q0 from accurate astrometric data of perihelion precession and changes in the third Kepler’s law in the Solar System fall short of 10 orders of magnitude with respect to estimates from observational cosmology. Future radio-ranging measurements of outer planets could improve actual bounds by 5 orders of magnitude.

  16. The effect of a massive object on an expanding universe

    NASA Astrophysics Data System (ADS)

    Nandra, Roshina; Lasenby, Anthony N.; Hobson, Michael P.

    2012-06-01

    A tetrad-based procedure is presented for solving Einstein's field equations for spherically symmetric systems; this approach was first discussed by Lasenby, Doran & Gull in the language of geometric algebra. The method is used to derive metrics describing a point mass in a spatially flat, open and closed expanding universe, respectively. In the spatially flat case, a simple coordinate transformation relates the metric to the corresponding one derived by McVittie. Nonetheless, our use of non-comoving ('physical') coordinates greatly facilitates physical interpretation. For the open and closed universes, our metrics describe different space-times to the corresponding McVittie metrics and we believe the latter to be incorrect. In the closed case, our metric possesses an image mass at the antipodal point of the universe. We calculate the geodesic equations for the spatially flat metric and interpret them. For radial motion in the Newtonian limit, the force acting on a test particle consists of the usual 1/r2 inwards component due to the central mass and a cosmological component proportional to r that is directed outwards (inwards) when the expansion of the universe is accelerating (decelerating). For the standard Λ cold dark matter concordance cosmology, the cosmological force reverses direction at about z≈ 0.67. We also derive an invariant fully general relativistic expression, valid for arbitrary spherically symmetric systems, for the force required to hold a test particle at rest relative to the central point mass.

  17. Geometric Explanation for AN Accelerating Universe

    NASA Astrophysics Data System (ADS)

    Bacinich, Edward J.

    2004-01-01

    The appearance and interpretation of an accelerating universe may be an observed distortion resulting from a universe defined by spherical geometry. The annihilation of Planck and anti-Planck mass is paramount in explaining the Big-Bang [1]. In a model similar to the standard model of a Riemannian-Friedmann-Lemaitre hypersphere, the primordial energy of the Big-Bang is released in the form of electromagnetic-like radiation that expands radiantly in every 4D direction from time zero in the structure of hyper-waves carried by Planck and anti-Planck bosons. The resulting geometry shows that time is synonymous with the lightspeed expansion of our universe. In this model we find that time is not parallel but radiant. This implies that time is a vector - where every place we observe has a unique time direction (angle) with a magnitude (age) and a light cone. The result of this condition is the illusion that the further back we look from our position in spacetime, space appears to be contracted and time appears to run slower both exponentially and logarithmically. Simply stated, we can not rely on observations unless we understand the geometric distortions inherent in curved photon paths.

  18. Expanding Advanced Civilizations in the Universe

    NASA Astrophysics Data System (ADS)

    Gros, C.

    The 1950 lunch-table remark by Enrico Fermi `Where is everybody' has started intensive scientific and philosophical discussions about what we call nowadays the `Fermi paradox': If there had been ever a single advanced civilization in the cosmological history of our galaxy, dedicated to expansion, it would have had plenty of time to colonize the entire galaxy via exponential growth. No evidence of present or past alien visits to earth are known to us, leading to the standard conclusion that no advanced expanding civilization has ever existed in the milky-way. This conclusion rest fundamentally on the ad-hoc assumption, that any alien civilizations dedicated to expansion at one time would remain dedicated to expansions forever. Considering our limited knowledge about alien civilizations we need however to relax this basic assumption. Here we show that a substantial and stable population of expanding advanced civilization might consequently exist in our galaxy.

  19. General conditions for scale-invariant perturbations in an expanding universe

    SciTech Connect

    Geshnizjani, Ghazal; Kinney, William H.; Dizgah, Azadeh Moradinezhad E-mail: whkinney@buffalo.edu

    2011-11-01

    We investigate the general properties of expanding cosmological models which generate scale-invariant curvature perturbations in the presence of a variable speed of sound. We show that in an expanding universe, generation of a super-Hubble, nearly scale-invariant spectrum of perturbations over a range of wavelengths consistent with observation requires at least one of three conditions: (1) accelerating expansion, (2) a speed of sound faster than the speed of light, or (3) super-Planckian energy density.

  20. Finite temperature quantum fields in expanding universes

    NASA Astrophysics Data System (ADS)

    Hu, B. L.

    1982-01-01

    The thermodynamics of an ideal relativistic quantum gas in expansion is studied. It is found that only for conformally invariant fields in conformally static spacetime can thermal equilibrium be strictly maintained. A finite temperature theory can be defined under the condition of quasi equilibrium when the background expansion is nearly adiabatic. The high temperature expansion of the energy density for massive nonconformal fields in Robertson-Walker universes and for conformal fields in Bianchi Type-I universes are calculated. The importance of these results on phase transition and quantum processes in the early universe is discussed.

  1. growl: Growth factor and growth rate of expanding universes

    NASA Astrophysics Data System (ADS)

    Hamilton, Andrew J. S.

    2015-12-01

    Growl calculates the linear growth factor Da and its logarithmic derivative dln D/dln a in expanding Friedmann-Robertson-Walker universes with arbitrary matter and vacuum densities. It permits rapid and stable numerical evaluation.

  2. Spherical Accretion in a Uniformly Expanding Universe

    NASA Astrophysics Data System (ADS)

    Colpi, Monica; Shapiro, Stuart L.; Wasserman, Ira

    1996-10-01

    We consider spherically symmetric accretion of material from an initially homogeneous, uniformly expanding medium onto a Newtonian point mass M. The gas is assumed to evolve adiabatically with a constant adiabatic index F, which we vary over the range Γ ɛ [1, 5/3]. We use a one-dimensional Lagrangian code to follow the spherical infall of material as a function of time. Outflowing shells gravitationally bound to the point mass fall back, giving rise to a inflow rate that, after a rapid rise, declines as a power law in time. If there were no outflow initially, Bondi accretion would result, with a characteristic accretion time-scale ta,0. For gas initially expanding at a uniform rate, with a radial velocity U = R/t0 at radius R, the behavior of the flow at all subsequent times is determined by ta,0/t0. If ta,0/t0 ≫ 1, the gas has no time to respond to pressure forces, so the fluid motion is nearly collisionless. In this case, only loosely bound shells are influenced by pressure gradients and are pushed outward. The late-time evolution of the mass accretion rate Mdot is close to the result for pure dust, and we develop a semianalytic model that accurately accounts for the small effect of pressure gradients in this limit. In the opposite regime, ta,0/t0 ≪ 1, pressure forces significantly affect the motion of the gas. At sufficiently early times, t ≤ ttr, the flow evolved along a sequence of quasi-stationary, Bondi-like states, with a time-dependent Mdot determined by the slowly varying gas density at large distances. However, at later times, t ≥ ttr, the fluid flow enters a dustllke regime; ttr is the time when the instantaneous Bondi accretion radius reaches the marginally bound radius. The transition time ttr depends sensitively on ta,0/t0 for a given Γ and can greatly exceed t0. We show that there exists a critical value Γ = 11/9, below which the transition from fluid to ballistic motion disappears. As one application of our calculations, we consider the

  3. Equations of motion in an Expanding Universe

    NASA Astrophysics Data System (ADS)

    Kopeikin, Sergei M.; Petrov, Alexander N.

    2015-06-01

    We make use of an effective field-theoretical approach to derive post-Newtonian equations of motion of hydrodynamical inhomogeneities in cosmology. The matter Lagrangian for the perturbed cosmological model includes dark matter, dark energy, and ordinary baryonic matter. The Lagrangian is expanded in an asymptotic Taylor series around a Friedmann-Lemaître-Robertson-Walker background. The small parameter of the decomposition is the magnitude of the metric tensor perturbation. Each term of the expansion series is gauge-invariant and all of them together form a basis for the successive post-Newtonian approximations around the background metric. The approximation scheme is covariant and the asymptotic nature of the Lagrangian decomposition does not require the post-Newtonian perturbations to be small though computationally it works the most effectively when the perturbed metric is close enough to the background metric. Temporal evolution of the background metric is governed by dark matter and dark energy and we associate the large-scale inhomogeneities of matter as those generated by the primordial cosmological perturbations in these two components with δρ/ρ ≤ 1. The small scale inhomogeneities are generated by the baryonic matter which is considered as a bare perturbation of the background gravitational field, dark matter and energy. Mathematically, the large scale structure inhomogeneities are given by the homogeneous solution of the post-Newtonian equations while the small scale inhomogeneities are described by a particular solution of these equations with the stress-energy tensor of the baryonic matter that admits δρ/ρ ≫ 1. We explicitly work out the field equations of the first post-Newtonian approximation in cosmology and derive the post-Newtonian equations of motion of the large and small scale inhomogeneities which generalize the covariant law of conservation of stress-energy-momentum tensor of matter in asymptotically-flat spacetime.

  4. Universe acceleration in brane world models

    NASA Astrophysics Data System (ADS)

    Chiou-Lahanas, C.; Diamandis, G. A.; Georgalas, B. C.

    2014-05-01

    We examine the cosmology induced on a brane moving in the background of a five-dimensional black hole, solution of the string effective action. The evolution, determined by the Israel junction conditions is found to be compatible with an accelerating universe with the present day acceleration coming after a decelerating phase. The possible species of the energy-momentum tensor, localized on the brane, for these solutions to be valid are discussed.

  5. Cosmic Accelerators: Engines of the Extreme Universe

    SciTech Connect

    Funk, Stefan

    2009-06-23

    The universe is home to numerous exotic and beautiful phenomena, some of which can generate almost inconceivable amounts of energy. While the night sky appears calm, it is populated by colossal explosions, jets from supermassive black holes, rapidly rotating neutron stars, and shock waves of gas moving at supersonic speeds. These accelerators in the sky boost particles to energies far beyond those we can produce on earth. New types of telescopes, including the Fermi Gamma-ray Space Telescope orbiting in space, are now discovering a host of new and more powerful accelerators. Please come and see how these observations are revising our picture of the most energetic phenomena in the universe.

  6. The Accelerator Markup Language and the Universal Accelerator Parser

    SciTech Connect

    Sagan, D.; Forster, M.; Bates, D.A.; Wolski, A.; Schmidt, F.; Walker, N.J.; Larrieu, T.; Roblin, Y.; Pelaia, T.; Tenenbaum, P.; Woodley, M.; Reiche, S.; /UCLA

    2006-10-06

    A major obstacle to collaboration on accelerator projects has been the sharing of lattice description files between modeling codes. To address this problem, a lattice description format called Accelerator Markup Language (AML) has been created. AML is based upon the standard eXtensible Markup Language (XML) format; this provides the flexibility for AML to be easily extended to satisfy changing requirements. In conjunction with AML, a software library, called the Universal Accelerator Parser (UAP), is being developed to speed the integration of AML into any program. The UAP is structured to make it relatively straightforward (by giving appropriate specifications) to read and write lattice files in any format. This will allow programs that use the UAP code to read a variety of different file formats. Additionally, this will greatly simplify conversion of files from one format to another. Currently, besides AML, the UAP supports the MAD lattice format.

  7. Browsing Your Virtual Library: The Case of Expanding Universe.

    ERIC Educational Resources Information Center

    Daniels, Wayne; Enright, Jeanne; Mackenzie, Scott

    1997-01-01

    Describes "Expanding Universe: a classified search tool for amateur astronomy," a Web site maintained by the Metropolitan Toronto Reference Library which uses a modified form of the Dewey Decimal Classification to organize a large file of astronomy hotlinks. Highlights include structure, HTML coding, design requirements, and future possibilities.…

  8. Einstein's conversion from his static to an expanding universe

    NASA Astrophysics Data System (ADS)

    Nussbaumer, Harry

    2014-02-01

    In 1917 Einstein initiated modern cosmology by postulating, based on general relativity, a homogenous, static, spatially curved universe. To counteract gravitational contraction he introduced the cosmological constant. In 1922 Alexander Friedman showed that Albert Einstein's fundamental equations also allow dynamical worlds, and in 1927 Georges Lemaître, backed by observational evidence, concluded that our universe was expanding. Einstein impetuously rejected Friedman's as well as Lemaître's findings. However, in 1931 he retracted his former static model in favour of a dynamic solution. This investigation follows Einstein on his hesitating path from a static to the expanding universe. Contrary to an often advocated belief the primary motive for his switch was not observational evidence, but the realisation that his static model was unstable.

  9. Accelerated expansion of the Universe in Gauss-Bonnet gravity

    SciTech Connect

    Dehghani, M.H.

    2004-09-15

    We show that in Gauss-Bonnet gravity with negative Gauss-Bonnet coefficient and without a cosmological constant, one can explain the acceleration of the expanding Universe. We first introduce a solution of the Gauss-Bonnet gravity with negative Gauss-Bonnet coefficient and no cosmological constant term in an empty (n+1)-dimensional bulk. This solution can generate a de Sitter spacetime with curvature n(n+1)/{l_brace}(n-2)(n-3) vertical bar {alpha} vertical bar {r_brace}. We show that an (n-1)-dimensional brane embedded in this bulk can have an expanding feature with acceleration. We also considered a four-dimensional brane world in a five-dimensional empty space with zero cosmological constant and obtain the modified Friedmann equations. The solution of these modified equations in matter-dominated era presents an expanding Universe with negative deceleration and positive jerk which is consistent with the recent cosmological data. We also find that for this solution, the 'n' th derivative of the scale factor with respect to time can be expressed only in terms of Hubble and deceleration parameters.

  10. The Naples University 3 MV tandem accelerator

    SciTech Connect

    Campajola, L.; Brondi, A.

    2013-07-18

    The 3 MV tandem accelerator of the Naples University is used for research activities and applications in many fields. At the beginning of operation (1977) the main utilization was in the field of nuclear physics. Later, the realization of new beam lines allowed the development of applied activities as radiocarbon dating, ion beam analysis, biophysics, ion implantation etc. At present, the availability of different ion sources and many improvements on the accelerator allow to run experiments in a wide range of subjects. An overview of the characteristics and major activities of the laboratory is presented.

  11. REDSHIFTS AND THE EXPANDING UNIVERSE - PARADIGM SHIFT OR SLOW DAWNING?

    NASA Astrophysics Data System (ADS)

    Raifeartaigh, Cormac O.

    2014-01-01

    The observation by Edwin Hubble of a linear relation between the redshift of the spiral nebulae and their radial distance marked one of the great discoveries of 20th century astronomy. This paper examines how the finding was interpreted as possible evidence for a universe of expanding radius by a number of theoreticians, but not astronomers. A brief review of the cosmic models of theoreticians such as Lemaître, Eddington, Einstein, de Sitter and Tolman is given, contrasting their different views of issues such as spatial curvature, the cosmological constant, the singularity and the formation of structure. It is argued that the concept of an expanding universe was not fully accepted for many years, and is best seen as the slow dawning of an idea rather than an abrupt Kuhnian paradigm shift.

  12. The Hubble party balloon and the expanding universe

    NASA Astrophysics Data System (ADS)

    Zendri, G.; Rosi, T.; Oss, S.

    2016-09-01

    We show that the metaphor of the inflated balloon used to describe expanding space-time according to the Hubble law can be transformed into a simple laboratory experiment. We obtain, in terms of measured recession speeds and distances of ink dots drawn on a party balloon, easy renditions of various cosmological models, such as the static one and the Einstein-De Sitter universe.

  13. An Intuitive Approach to Visualizing the Expanding Universe

    NASA Astrophysics Data System (ADS)

    Sherard, Paul K.

    2015-08-01

    Visualizing the expansion of the universe for a general audience can be a daunting task. Here we present an intuitive representation of the expansion of the universe. To first-order approximation, the expansion of the universe the can be fit to a constant expansion rate. This simple model extrapolates this approximation for the entire history of the universe to create an intuitive expansion diagram that displays the essential characteristics of space-time and the casually and non-casually connected universe. Here, Minkowski space (zero curvature) is transformed to a 3-sphere model which is represented in 2D as a 1-sphere (a circle). The representation is similar to Penrose diagrams where, in this case, space and time have finite representations. Although the model is simplistic, it offers a visual representation of many of the characteristics of the observable universe. Namely, Hubble flow, a horizon, and a clear representation the space-time light paths of that converge on the observer at the present moment (the observable universe). Such diagrams could be valuable for educators to elucidate to an interested audience, including undergraduate and graduate astronomy students, the nature of our expanding universe.

  14. Kuss Middle School: Expanding Time to Accelerate School Improvement

    ERIC Educational Resources Information Center

    Massachusetts 2020, 2012

    2012-01-01

    In 2004, Kuss Middle School became the first school declared "Chronically Underperforming" by the state of Massachusetts. But by 2010, Kuss had transformed itself into a model for schools around the country seeking a comprehensive turnaround strategy. Kuss is using increased learning time as the primary catalyst to accelerate learning, deepen…

  15. Theory Challenges of the Accelerating Universe

    SciTech Connect

    Linder, Eric V.

    2007-03-05

    The accelerating expansion of the universe presents an exciting, fundamental challenge to the standard models of particle physics and cosmology. I highlight some of the outstanding challenges in both developing theoretical models and interpreting without bias the observational results from precision cosmology experiments in the next decade that will return data to help reveal the nature of the new physics. Examples given focus on distinguishing a new component of energy from a new law of gravity, and the effect of early dark energy on baryon acoustic oscillations.

  16. Medical humanities and philosophy: is the universe expanding or contracting?

    PubMed

    Stempsey, William E

    2007-12-01

    The question of whether the universe is expanding or contracting serves as a model for current questions facing the medical humanities. The medical humanities might aptly be described as a metamedical multiverse encompassing many separate universes of discourse, the most prominent of which is probably bioethics. Bioethics, however, is increasingly developing into a new interdisciplinary discipline, and threatens to engulf the other medical humanities, robbing them of their own distinctive contributions to metamedicine. The philosophy of medicine considered as a distinct field of study has suffered as a result. Indeed, consensus on whether the philosophy of medicine even constitutes a legitimate field of study is lacking. This paper presents an argument for the importance of a broad conception of the philosophy of medicine and the central role it should play in organizing and interpreting the various fields of study that make up the metamedical multiverse.

  17. Medical humanities and philosophy: is the universe expanding or contracting?

    PubMed

    Stempsey, William E

    2007-12-01

    The question of whether the universe is expanding or contracting serves as a model for current questions facing the medical humanities. The medical humanities might aptly be described as a metamedical multiverse encompassing many separate universes of discourse, the most prominent of which is probably bioethics. Bioethics, however, is increasingly developing into a new interdisciplinary discipline, and threatens to engulf the other medical humanities, robbing them of their own distinctive contributions to metamedicine. The philosophy of medicine considered as a distinct field of study has suffered as a result. Indeed, consensus on whether the philosophy of medicine even constitutes a legitimate field of study is lacking. This paper presents an argument for the importance of a broad conception of the philosophy of medicine and the central role it should play in organizing and interpreting the various fields of study that make up the metamedical multiverse. PMID:17549604

  18. Torsion cosmology and the accelerating universe

    SciTech Connect

    Shie, K.-F.; Nester, James M.; Yo, H.-J.

    2008-07-15

    Investigations of the dynamic modes of the Poincare gauge theory of gravity found only two good propagating torsion modes; they are effectively a scalar and a pseudoscalar. Cosmology affords a natural situation where one might see observational effects of these modes. Here, we consider only the 'scalar torsion' mode. This mode has certain distinctive and interesting qualities. In particular, this type of torsion does not interact directly with any known matter, and it allows a critical nonzero value for the affine scalar curvature. Via numerical evolution of the coupled nonlinear equations we show that this mode can contribute an oscillating aspect to the expansion rate of the Universe. From the examination of specific cases of the parameters and initial conditions we show that for suitable ranges of the parameters the dynamic 'scalar torsion' model can display features similar to those of the presently observed accelerating universe.

  19. Ion trap simulations of quantum fields in an expanding universe.

    PubMed

    Alsing, Paul M; Dowling, Jonathan P; Milburn, G J

    2005-06-10

    We propose an experiment in which the phonon excitation of ion(s) in a trap, with a trap frequency exponentially modulated at rate kappa, exhibits a thermal spectrum with an "Unruh" temperature given by k(B)T=Planck kappa. We discuss the similarities of this experiment to the response of detectors in a de Sitter universe and the usual Unruh effect for uniformly accelerated detectors. We demonstrate a new Unruh effect for detectors that respond to antinormally ordered moments using the ion's first blue sideband transition.

  20. Expanding research capacity and accelerating AIDS vaccine development in Asia.

    PubMed

    Excler, Jean-Louis; Pitisuttithum, Punnee; Rerks-Ngarm, Supachai; Shao, Yiming; Zhang, Linqi; Tamashiro, Hiko; Osmanov, Saladin

    2008-07-01

    According to the Joint UN Program on AIDS (UNAIDS), an estimated 4.9 million adults and children are living with HIV in Asia and the Pacific. Refinement and development of existing and new prevention and treatment technologies--including safe, effective, and accessible AIDS vaccines--are urgent public health priorities. The Asian region faces several challenges for AIDS vaccine development. There are multiple genetic variants of HIV-1 driving the epidemic in the region and too few vaccine candidates in the pipeline targeting those subtypes. Low HIV incidence throughout the region means that trial sites must recruit larger numbers of volunteers and shift their focus to higher-risk populations where incidence is higher. Also, the cultural, economic, and political diversity of the region may render collaboration very complex, but also beneficial at a regional level. Recognizing that collaborating as a region could foster and accelerate AIDS vaccine development, participants at the Sapporo International Consultation recommended that an AIDS Vaccine Asian Network (AVAN) be created to facilitate interactions between donors and funding opportunities, increase regional clinical trial and production capacity, support region-specific advocacy and communication strategies, contribute to the Global HIV Vaccine Enterprise Scientific Plan, prepare a regional approach for future vaccine deployment, and develop a regional platform for clinical trials including harmonized legal, regulatory, and ethical frameworks. PMID:19058617

  1. Kinematic Repulsions Between Inertial Systems in AN Expanding Inflationary Universe

    NASA Astrophysics Data System (ADS)

    Savickas, D.

    2013-09-01

    The cosmological background radiation is observed to be isotropic only within a coordinate system that is at rest relative to its local Hubble drift. This indicates that the Hubble motion describes the recessional motion of an inertial system that is at rest relative to its local Hubble drift. It is shown that when the Hubble parameter is kinematically defined directly in terms of the positions and velocities of mass particles in the universe, it then also defines inertial systems themselves in terms of the distribution and motion of mass particles. It is independent of the velocity of photons because photons always have a speed c relative to the inertial system in which they are located. Therefore the definition of their velocity depends on the definition of the Hubble parameter itself and cannot be used to define H. The derivative of the kinematically defined Hubble parameter with respect to time is shown to always be positive and highly repulsive at the time of the origin of the universe. A model is used which describes a universe that is balanced at the time of its origin so that H approaches zero as the universe expands to infinity.

  2. Noncommutative accelerated multidimensional universe dominated by quintessence

    NASA Astrophysics Data System (ADS)

    El-Nabulsi, Ahmad Rami

    2010-04-01

    Noncommutative Geometry recently attracted growing interest of cosmologists, mainly after the greatest success of unifying the forces of nature into a single gravitational spectral action in a purely algebraic way, rather than as being an entirely new formalism. In the present work, we discuss a multidimensional Friedmann-Robertson-Walker flat universe in which the perfect fluid has a Gaussian profile in time and depends on a fundamental minimal length sqrt{θ} like ρ= ρ(0)exp (- t 2/4 θ) for some positive constant ρ(0). This special form is motivated by a more recent noncommutative inflationary cosmological model, which was found to be able to drive the universe through a bounce without the need of any scalar field. Furthermore, we conjecture that the generalized equation of state has the special form p= ω a m ρ- ρ,( ω, m)∈ℝ where a( t) is the scale factor. It was found that the expansion of the multidimensional universe accelerates in time and is dominated for very large time by quintessence. Many additional consequences are revealed and discussed in some detail.

  3. Flat-top oscillons in an expanding universe

    SciTech Connect

    Amin, Mustafa A.; Shirokoff, David

    2010-04-15

    Oscillons are extremely long lived, oscillatory, spatially localized field configurations that arise from generic initial conditions in a large number of nonlinear field theories. With an eye towards their cosmological implications, we investigate their properties in an expanding universe. We (1) provide an analytic solution for one-dimensional oscillons (for the models under consideration) and discuss their generalization to three dimensions, (2) discuss their stability against long wavelength perturbations, and (3) estimate the effects of expansion on their shapes and lifetimes. In particular, we discuss a new, extended class of oscillons with surprisingly flat tops. We show that these flat-topped oscillons are more robust against collapse instabilities in (3+1) dimensions than their usual counterparts. Unlike the solutions found in the small amplitude analysis, the width of these configurations is a nonmonotonic function of their amplitudes.

  4. Expanded Markers of Success in Introductory University Physics

    NASA Astrophysics Data System (ADS)

    Goertzen, Renee Michelle; Brewe, Eric; Kramer, Laird

    2013-01-01

    As part of our Physics Education Research Group efforts to transform the physics instruction at Florida International University (FIU), we have focused attention on how to assess the reforms we implement. In this paper, we argue that the physics education community should expand the ways that it measures students' success beyond grades and conceptual inventory scores to include assessments of students' participation in a learning community and changes in their attitudes. We present case studies of three introductory undergraduate physics students' increasing participation in the physics learning community at FIU, which is a large, urban, Hispanic-serving institution. In previous work, we have reported gains in conceptual learning and attitudes about learning science in those students enrolled in the introductory courses at FIU taught with Modeling Instruction, which operates in a collaborative learning environment [Brewe, E., Kramer, L., & O'Brien, G. (2009). Modeling instruction: Positive attitudinal shifts in introductory physics measured with CLASS. Physical Review Special Topics-Physics Education Research, 5(1). doi: 10.1103/PhysRevSTPER.5.013102]. This paper expands upon those results in considering the variety of opportunities for participating in the physics learning community and by closely examining three aspect of student participation: students' attitudes about learning physics, their ties within the physics classroom, and their relationships within the physics learning community. This provides a more comprehensive understanding of how students in underrepresented groups may become successful physics learners.

  5. Hubble's Cosmology: From a Finite Expanding Universe to a Static Endless Universe

    NASA Astrophysics Data System (ADS)

    Assis, A. K. T.; Neves, M. C. D.; Soares, D. S. L.

    2009-12-01

    We analyze the views of Edwin Hubble (1889-1953) as regards the large scale structure of the universe. In 1929 he initially accepted a finite expanding universe in order to explain the redshifts of distant galaxies. Later on he turned to an infinite stationary universe and a new principle of nature in order to explain the same phenomena. Initially, he was impressed by the agreement of his redshift-distance relation with one of the predictions of de Sitter's cosmological model, namely, the so-called "de Sitter effect'', the phenomenon of the scattering of material particles, leading to an expanding universe. A number of observational evidences, though, made him highly skeptical with such a scenario. They were better accounted for by an infinite static universe. The evidences he found were: (i) the huge values he was getting for the "recession'' velocities of the nebulae (1,800 km s-1 in 1929 up to 42,000 km s-1 in 1942, leading to v/c = 1/7), with the redshifts interpreted as velocity-shifts. All other known real velocities of large astronomical bodies are much smaller than these. (ii) The "number effect'' test, which is the running of nebulae luminosity with redshift. Hubble found that a static universe is, within the observational uncertainties, slightly favored. The test is equivalent to the modern "Tolman effect,'' for galaxy surface brightnesses, whose results are still a matter of dispute. (iii) The smallness of the size and the age of the curved expanding universe, implied by the expansion rate that he had determined, and, (iv) the fact that a uniform distribution of galaxies on large scales is more easily obtained from galaxy counts, when a static and flat model is considered. In an expanding and closed universe, Hubble found that homogeneity was only obtained at the cost of a large curvature. We show, by quoting his works, that Hubble remained cautiously against the big bang until the end of his life, contrary to the statements of many modern authors. In

  6. Rotating black holes in an expanding Universe from fake supergravity

    NASA Astrophysics Data System (ADS)

    Chimento, Samuele; Klemm, Dietmar

    2015-02-01

    Using the recipe of Meessen and Palomo-Lozano (2009 J. High Energy Phys. JHEP05(2009)042), where all fake supersymmetric backgrounds of matter-coupled fake N = 2, d = 4 gauged supergravity were classified, we construct dynamical rotating black holes in an expanding FLRW Universe. This is done for two different prepotentials that are both truncations of the stu model and correspond to just one vector multiplet. In this scenario, the cosmic expansion is driven by two U(1) gauge fields and by a complex scalar that rolls down its potential. Generically, the solutions of Meessen and Palomo-Lozano are fibrations over a Gauduchon-Tod base space, and we make three different choices for this base, namely flat space, the three-sphere and the Berger sphere. In the first two cases, the black holes are determined by harmonic functions on the base, while in the last case they obey a deformed Laplace equation that contains the squashing parameter of the Berger sphere. This is the generalization to a cosmological context of the usual recipe in ungauged supergravity, where black holes are given in terms of harmonic functions on three-dimensional Euclidean space. The constructed solutions may be instrumental in addressing analytically certain aspects of black hole physics in a dynamical context.

  7. A growing family: the expanding universe of the bacterial cytoskeleton.

    PubMed

    Ingerson-Mahar, Michael; Gitai, Zemer

    2012-01-01

    Cytoskeletal proteins are important mediators of cellular organization in both eukaryotes and bacteria. In the past, cytoskeletal studies have largely focused on three major cytoskeletal families, namely the eukaryotic actin, tubulin, and intermediate filament (IF) proteins and their bacterial homologs MreB, FtsZ, and crescentin. However, mounting evidence suggests that these proteins represent only the tip of the iceberg, as the cellular cytoskeletal network is far more complex. In bacteria, each of MreB, FtsZ, and crescentin represents only one member of large families of diverse homologs. There are also newly identified bacterial cytoskeletal proteins with no eukaryotic homologs, such as WACA proteins and bactofilins. Furthermore, there are universally conserved proteins, such as the metabolic enzyme CtpS, that assemble into filamentous structures that can be repurposed for structural cytoskeletal functions. Recent studies have also identified an increasing number of eukaryotic cytoskeletal proteins that are unrelated to actin, tubulin, and IFs, such that expanding our understanding of cytoskeletal proteins is advancing the understanding of the cell biology of all organisms. Here, we summarize the recent explosion in the identification of new members of the bacterial cytoskeleton and describe a hypothesis for the evolution of the cytoskeleton from self-assembling enzymes.

  8. Expanding wave solutions of the Einstein equations that induce an anomalous acceleration into the Standard Model of Cosmology.

    PubMed

    Temple, Blake; Smoller, Joel

    2009-08-25

    We derive a system of three coupled equations that implicitly defines a continuous one-parameter family of expanding wave solutions of the Einstein equations, such that the Friedmann universe associated with the pure radiation phase of the Standard Model of Cosmology is embedded as a single point in this family. By approximating solutions near the center to leading order in the Hubble length, the family reduces to an explicit one-parameter family of expanding spacetimes, given in closed form, that represents a perturbation of the Standard Model. By introducing a comoving coordinate system, we calculate the correction to the Hubble constant as well as the exact leading order quadratic correction to the redshift vs. luminosity relation for an observer at the center. The correction to redshift vs. luminosity entails an adjustable free parameter that introduces an anomalous acceleration. We conclude (by continuity) that corrections to the redshift vs. luminosity relation observed after the radiation phase of the Big Bang can be accounted for, at the leading order quadratic level, by adjustment of this free parameter. The next order correction is then a prediction. Since nonlinearities alone could actuate dissipation and decay in the conservation laws associated with the highly nonlinear radiation phase and since noninteracting expanding waves represent possible time-asymptotic wave patterns that could result, we propose to further investigate the possibility that these corrections to the Standard Model might be the source of the anomalous acceleration of the galaxies, an explanation not requiring the cosmological constant or dark energy.

  9. Expanding wave solutions of the Einstein equations that induce an anomalous acceleration into the Standard Model of Cosmology

    PubMed Central

    Temple, Blake; Smoller, Joel

    2009-01-01

    We derive a system of three coupled equations that implicitly defines a continuous one-parameter family of expanding wave solutions of the Einstein equations, such that the Friedmann universe associated with the pure radiation phase of the Standard Model of Cosmology is embedded as a single point in this family. By approximating solutions near the center to leading order in the Hubble length, the family reduces to an explicit one-parameter family of expanding spacetimes, given in closed form, that represents a perturbation of the Standard Model. By introducing a comoving coordinate system, we calculate the correction to the Hubble constant as well as the exact leading order quadratic correction to the redshift vs. luminosity relation for an observer at the center. The correction to redshift vs. luminosity entails an adjustable free parameter that introduces an anomalous acceleration. We conclude (by continuity) that corrections to the redshift vs. luminosity relation observed after the radiation phase of the Big Bang can be accounted for, at the leading order quadratic level, by adjustment of this free parameter. The next order correction is then a prediction. Since nonlinearities alone could actuate dissipation and decay in the conservation laws associated with the highly nonlinear radiation phase and since noninteracting expanding waves represent possible time-asymptotic wave patterns that could result, we propose to further investigate the possibility that these corrections to the Standard Model might be the source of the anomalous acceleration of the galaxies, an explanation not requiring the cosmological constant or dark energy. PMID:19706502

  10. Expanding wave solutions of the Einstein equations that induce an anomalous acceleration into the Standard Model of Cosmology.

    PubMed

    Temple, Blake; Smoller, Joel

    2009-08-25

    We derive a system of three coupled equations that implicitly defines a continuous one-parameter family of expanding wave solutions of the Einstein equations, such that the Friedmann universe associated with the pure radiation phase of the Standard Model of Cosmology is embedded as a single point in this family. By approximating solutions near the center to leading order in the Hubble length, the family reduces to an explicit one-parameter family of expanding spacetimes, given in closed form, that represents a perturbation of the Standard Model. By introducing a comoving coordinate system, we calculate the correction to the Hubble constant as well as the exact leading order quadratic correction to the redshift vs. luminosity relation for an observer at the center. The correction to redshift vs. luminosity entails an adjustable free parameter that introduces an anomalous acceleration. We conclude (by continuity) that corrections to the redshift vs. luminosity relation observed after the radiation phase of the Big Bang can be accounted for, at the leading order quadratic level, by adjustment of this free parameter. The next order correction is then a prediction. Since nonlinearities alone could actuate dissipation and decay in the conservation laws associated with the highly nonlinear radiation phase and since noninteracting expanding waves represent possible time-asymptotic wave patterns that could result, we propose to further investigate the possibility that these corrections to the Standard Model might be the source of the anomalous acceleration of the galaxies, an explanation not requiring the cosmological constant or dark energy. PMID:19706502

  11. Life, the Universe, and Nothing: Life and Death in an Ever-expanding Universe

    SciTech Connect

    Krauss, Lawrence M.; Starkman, Glenn D.

    2000-03-01

    Current evidence suggests that the cosmological constant is not zero, or that we live in an open universe. We examine the implications for the future under these assumptions, and find that they are striking. If the universe is cosmological constant-dominated, our ability to probe the evolution of large-scale structure will decrease with time; presently observable distant sources will disappear on a timescale comparable to the period of stellar burning. Moreover, while the universe might expand forever, the integrated conscious lifetime of any civilization will be finite, although it can be astronomically long. We argue that this latter result is far more general. In the absence of possible exotic and uncertain strong gravitational effects, the total information recoverable by any civilization over the entire history of our universe is finite. Assuming that consciousness has a physical computational basis, and therefore is ultimately governed by quantum mechanics, life cannot be eternal. (c) 2000 The American Astronomical Society.

  12. A Possible Interpretation of Dark Energy and Matter of the Expanding Universe

    SciTech Connect

    Lehnert, B.

    2009-11-10

    At present the expanding universe is observed to be dominated by the not fully understood concepts of dark energy and matter, in a conceived almost flat Euclidian geometry. As one of the possible efforts to understand its global behaviour, the present paper attempts to explain these concepts in terms of the pressure force and gravity of a spherical photon gas cloud of zero point energy, in flat geometry. A difficult point concerns the frequency distribution of the zero point energy oscillations which leads to the unacceptable result of an infinite total energy. A modification of this distribution is therefore proposed which results in finite energy density. A corresponding equilibrium is investigated, as well as small dynamic deviations from it, to form a basis for a model of the expanding universe. Provided that the crucial points of the present approach hold true, the model satisfies the requirements of cosmic linear dimensions, results in an estimated acceleration of the expansion being of the order of the observed one, presents a possible solution of the coincidence problem of dark energy and matter, and provides one of the possible explanations of the observed excess of high-energy electrons and positrons in recent balloon and satellite experiments.

  13. Expanding the Education Universe: A Fifty-State Strategy for Course Choice

    ERIC Educational Resources Information Center

    Brickman, Michael

    2014-01-01

    After twenty years of expanding school-choice options, state leaders, educators, and families have a new tool: course choice, a strategy for students to learn from unconventional providers that might range from top-tier universities or innovative community colleges to local employers, labs, or hospitals. In "Expanding the Education Universe:…

  14. Supernovae, an accelerating universe and the cosmological constant

    PubMed Central

    Kirshner, Robert P.

    1999-01-01

    Observations of supernova explosions halfway back to the Big Bang give plausible evidence that the expansion of the universe has been accelerating since that epoch, approximately 8 billion years ago and suggest that energy associated with the vacuum itself may be responsible for the acceleration. PMID:10200242

  15. Accelerated universes from type IIA compactifications

    NASA Astrophysics Data System (ADS)

    Blåbäck, Johan; Danielsson, Ulf; Dibitetto, Giuseppe

    2014-03-01

    We study slow-roll accelerating cosmologies arising from geometric compactifications of type IIA string theory on T6/(Bbb Z2 × Bbb Z2). With the aid of a genetic algorithm, we are able to find quasi-de Sitter backgrounds with both slow-roll parameters of order 0.1. Furthermore, we study their evolution by numerically solving the corresponding time-dependent equations of motion, and we show that they actually display a few e-folds of accelerated expansion. Finally, we comment on their perturbative reliability.

  16. Accelerated universes from type IIA compactifications

    SciTech Connect

    Blåbäck, Johan; Danielsson, Ulf; Dibitetto, Giuseppe E-mail: ulf.danielsson@physics.uu.se

    2014-03-01

    We study slow-roll accelerating cosmologies arising from geometric compactifications of type IIA string theory on T{sup 6}/(Z{sub 2}  ×  Z{sub 2}). With the aid of a genetic algorithm, we are able to find quasi-de Sitter backgrounds with both slow-roll parameters of order 0.1. Furthermore, we study their evolution by numerically solving the corresponding time-dependent equations of motion, and we show that they actually display a few e-folds of accelerated expansion. Finally, we comment on their perturbative reliability.

  17. Advanced Accelerator Applications University Participation Program

    SciTech Connect

    Y. Chen; A. Hechanova

    2007-07-25

    Our research tasks span the range of technology areas for transmutation, gas-cooled reactor technology, and high temperature heat exchangers, including separation of actinides from spent nuclear fuel, methods of fuel fabrication, reactor-accelerator coupled experiments, corrosion of materials exposed to lead-bismuth eutectic, and special nuclear materials protection and accountability.

  18. The extravagant universe : exploding stars, dark energy and the accelerating cosmos

    NASA Astrophysics Data System (ADS)

    Kirshner, Robert P.

    One of the world's leading astronomers tells the story of unlocking an astonishing cosmic secret. Supernova expert Robert Kirshner brings readers inside a lively research team on the quest that led them to an extraordinary cosmological discovery: the expansion of the universe is accelerating under the influence of a dark energy that makes space itself expand. Measurements of light from exploding stars--some of them halfway across the universe--let these astronomers trace the history of cosmic expansion. The results have been amazing. Instead of a universe slowing down due to gravity as theory predicted, observations reveal a universe whose expansion is speeding up. This measurement of dark energy--a quality of space itself that causes cosmic acceleration--points to a gaping hole in our understanding of fundamental physics. In 1917, Einstein proposed the "cosmological constant" to explain a static universe. When observations proved that the universe was expanding, he cast this early form of dark energy aside. But recent observations described first-hand in this book show that the cosmological constant--or something just like it--dominates the universe's mass and energy budget and determines its fate and shape. Warned by Einstein's blunder, and contradicted by the initial results of a competing research team, Kirshner and his colleagues were reluctant to accept their own result. But, convinced by evidence built on their hard-earned understanding of exploding stars, they announced their conclusion that the universe is accelerating in February 1998. Other lines of inquiry and parallel supernova research now support a new synthesis of a cosmos dominated by dark energy but also containing several forms of dark matter. We live in an extravagant universe with a surprising number of essential ingredients: the real universe we measure is not the simplest one we could imagine. This book invites any reader to share in the excitement of a remarkable adventure of discovery.

  19. Heating and acceleration of solar wind ions by turbulent wave spectrum in inhomogeneous expanding plasma

    NASA Astrophysics Data System (ADS)

    Ofman, Leon; Ozak, Nataly; Viñas, Adolfo F.

    2016-03-01

    Near the Sun (< 10Rs) the acceleration, heating, and propagation of the solar wind are likely affected by the background inhomogeneities of the magnetized plasma. The heating and the acceleration of the solar wind ions by turbulent wave spectrum in inhomogeneous plasma is studied using a 2.5D hybrid model. The hybrid model describes the kinetics of the ions, while the electrons are modeled as massless neutralizing fluid in an expanding box approach. Turbulent magnetic fluctuations dominated by power-law frequency spectra, which are evident from in-situ as well as remote sensing measurements, are used in our models. The effects of background density inhomogeneity across the magnetic field on the resonant ion heating are studied. The effect of super-Alfvénic ion drift on the ion heating is investigated. It is found that the turbulent wave spectrum of initially parallel propagating waves cascades to oblique modes, and leads to enhanced resonant ion heating due to the inhomogeneity. The acceleration of the solar wind ions is achieved by the parametric instability of large amplitude waves in the spectrum, and is also affected by the inhomogeneity. The results of the study provide the ion temperature anisotropy and drift velocity temporal evolution due to relaxation of the instability. The non-Maxwellian velocity distribution functions (VDFs) of the ions are modeled in the inhomogeneous solar wind plasma in the acceleration region close to the Sun.

  20. Time and Irreversibility in AN Accelerating Universe

    NASA Astrophysics Data System (ADS)

    Romero, Gustavo E.; Pérez, Daniela

    It is a remarkable fact that all processes occurring in the observable universe are irreversible, whereas the equations through which the fundamental laws of physics are formulated are invariant under time reversal. The emergence of irreversibility from the fundamental laws has been a topic of consideration by physicists, astronomers and philosophers since Boltzmann's formulation of his famous "H" theorem. In this paper, we shall discuss some aspects of this problem and its connection with the dynamics of spacetime, within the framework of modern cosmology. We conclude that the existence of cosmological horizons allows a coupling of the global state of the universe with the local events determined through electromagnetic processes.

  1. The expanding regulatory universe of p53 in gastrointestinal cancer.

    PubMed

    Fesler, Andrew; Zhang, Ning; Ju, Jingfang

    2016-01-01

    Tumor suppresser gene TP53 is one of the most frequently deleted or mutated genes in gastrointestinal cancers. As a transcription factor, p53 regulates a number of important protein coding genes to control cell cycle, cell death, DNA damage/repair, stemness, differentiation and other key cellular functions. In addition, p53 is also able to activate the expression of a number of small non-coding microRNAs (miRNAs) through direct binding to the promoter region of these miRNAs.  Many miRNAs have been identified to be potential tumor suppressors by regulating key effecter target mRNAs. Our understanding of the regulatory network of p53 has recently expanded to include long non-coding RNAs (lncRNAs). Like miRNA, lncRNAs have been found to play important roles in cancer biology.  With our increased understanding of the important functions of these non-coding RNAs and their relationship with p53, we are gaining exciting new insights into the biology and function of cells in response to various growth environment changes. In this review we summarize the current understanding of the ever expanding involvement of non-coding RNAs in the p53 regulatory network and its implications for our understanding of gastrointestinal cancer.

  2. The expanding regulatory universe of p53 in gastrointestinal cancer.

    PubMed

    Fesler, Andrew; Zhang, Ning; Ju, Jingfang

    2016-01-01

    Tumor suppresser gene TP53 is one of the most frequently deleted or mutated genes in gastrointestinal cancers. As a transcription factor, p53 regulates a number of important protein coding genes to control cell cycle, cell death, DNA damage/repair, stemness, differentiation and other key cellular functions. In addition, p53 is also able to activate the expression of a number of small non-coding microRNAs (miRNAs) through direct binding to the promoter region of these miRNAs.  Many miRNAs have been identified to be potential tumor suppressors by regulating key effecter target mRNAs. Our understanding of the regulatory network of p53 has recently expanded to include long non-coding RNAs (lncRNAs). Like miRNA, lncRNAs have been found to play important roles in cancer biology.  With our increased understanding of the important functions of these non-coding RNAs and their relationship with p53, we are gaining exciting new insights into the biology and function of cells in response to various growth environment changes. In this review we summarize the current understanding of the ever expanding involvement of non-coding RNAs in the p53 regulatory network and its implications for our understanding of gastrointestinal cancer. PMID:27508057

  3. The expanding regulatory universe of p53 in gastrointestinal cancer

    PubMed Central

    Fesler, Andrew; Zhang, Ning; Ju, Jingfang

    2016-01-01

    Tumor suppresser gene TP53 is one of the most frequently deleted or mutated genes in gastrointestinal cancers. As a transcription factor, p53 regulates a number of important protein coding genes to control cell cycle, cell death, DNA damage/repair, stemness, differentiation and other key cellular functions. In addition, p53 is also able to activate the expression of a number of small non-coding microRNAs (miRNAs) through direct binding to the promoter region of these miRNAs.  Many miRNAs have been identified to be potential tumor suppressors by regulating key effecter target mRNAs. Our understanding of the regulatory network of p53 has recently expanded to include long non-coding RNAs (lncRNAs). Like miRNA, lncRNAs have been found to play important roles in cancer biology.  With our increased understanding of the important functions of these non-coding RNAs and their relationship with p53, we are gaining exciting new insights into the biology and function of cells in response to various growth environment changes. In this review we summarize the current understanding of the ever expanding involvement of non-coding RNAs in the p53 regulatory network and its implications for our understanding of gastrointestinal cancer. PMID:27508057

  4. Expanding School-District/University Partnerships to Advance Health Promoting Schools Implementation and Efficacy in Taiwan

    ERIC Educational Resources Information Center

    Liu, Chieh-Hsing; Chang, Fong-Ching; Liao, Li-Ling; Niu, Yu-Zhen; Cheng, Chi-Chia; Shih, Shu-Fang; Chang, Tzu-Chau; Chou, Hsin-Pei

    2015-01-01

    In 2011, the Taiwan government expanded its support of school-district/university partnership programs that promote the implementation of the evidenced-based Health Promoting Schools (HPS) program. This study examined whether expanding the support for this initiative was effective in advancing HPS implementation, perceived HPS impact and perceived…

  5. Promising Practices: New York State Universal Prekindergarten. Expanded Edition.

    ERIC Educational Resources Information Center

    Hicks, Susan A.; Lekies, Kristi S.; Cochran, Mon

    In response to recent state legislation, school districts in New York developed plans for universal prekindergarten (UPK) programs for the 1998-1999 academic year. Based on an analysis of the first year prekindergarten program plans for 63 upstate New York districts (with follow-up information on 29 districts) and 32 New York City districts, this…

  6. The Power of Montessori's Positive Psychology in an Expanding Universe.

    ERIC Educational Resources Information Center

    Haines, Annette

    1999-01-01

    Relates Montessori theory of development with the concept of connection to the universe and natural world, noting Montessori education's role in nurturing reestablished connection with the natural world. Describes events leading to a fulfilled life as part of psychological normalization, noting the importance of identifying positive tendencies of…

  7. University Students and Parents Together: Expanding Undergraduates' Experiential Base.

    ERIC Educational Resources Information Center

    Warner, Laverne

    2000-01-01

    A collaborataive program allowed early childhood certification students to gain experience working with parents of young children. Preservice teachers from Sam Houston State University worked with the Conroe Independent School District (Texas) Even Start Family Literacy Program as part of their parent education program. Students developed and…

  8. Expanding the Universe of "Astronomy on Tap" Public Outreach Events

    NASA Astrophysics Data System (ADS)

    Rice, Emily L.; Levine, Brian; Livermore, Rachael C.; Silverman, Jeffrey M.; LaMassa, Stephanie M.; Tyndall, Amy; Muna, Demitri; Garofali, Kristen; Morris, Brett; Byler, Nell; Fyhrie, Adalyn; Rehnberg, Morgan; Hart, Quyen N.; Connelly, Jennifer L.; Silvia, Devin W.; Morrison, Sarah J.; Agarwal, Bhaskar; Tremblay, Grant; Schwamb, Megan E.

    2016-01-01

    Astronomy on Tap (AoT, astronomyontap.org) is free public outreach event featuring engaging science presentations in bars, often combined with music, games, and prizes, to encourage a fun, interactive atmosphere. AoT events feature several short astronomy-related presentations primarily by local professional scientists, but also by visiting scientists, students, educators, amatuer astronomers, writers, and artists. Events are held in social venues (bars, coffee shops, art galleries, etc.) in order to bring science directly to the public in a relaxed, informal atmosphere. With this we hope to engage a more diverse audience than typical lectures at academic and cultural institutions and to develop enthusiasm for science among voting, tax-paying adults. The flexible format and content of an AoT event is easy to adapt and expand based on the priorities, resources, and interests of local organizers. The social nature of AoT events provides important professional development and networking opportunities in science communication. Since the first New York City event in April 2013, Astronomy on Tap has expanded to more than ten cities globally, including monthly events in NYC, Austin, Seattle, and Tucson; semi-regular events in Columbus, New Haven, Santiago, Toronto, and Denver; occasional (so far) events in Rochester (NY), Baltimore, Lansing, and Washington, DC; and one-off events in Chicago and Taipei. Several venues regularly attract audiences of over 200 people. We have received media coverage online, in print, and occasionally even on radio and television. In this poster we describe the overarching goals and characteristics of AoT events, distinct adaptations of various locations, resources we have developed, and the methods we use to coordinate among the worldwide local organizers.

  9. The Turning and Evolution of the Recent Acceleration Universe

    NASA Astrophysics Data System (ADS)

    Zhang, Tianxi; Tan, A.

    2007-05-01

    The turning point and evolution characteristics of the universe are investigated through solving the Friedmann equation with a non-zero cosmological constant. Choosing the present-time Hubble constant, the radius of the present universe , and the density parameter in matter as three key parameters, we obtain the density parameter in dark energy, the cosmological constant, the mass of the universe, the turning point redshif, the age of the present universe, and the time-dependent expansion rate, velocity, radius, and acceleration parameter of the universe. It is shown that the turing point redshift is soly dependent of the density parameters in matter and dark energy. For the flat universe, it turned from past deceleration to recent acceleration when its size was 1/2 to 2/3 of the present size if the density parameter in matter is between 0.2 and 0.4. The expansion rate is very large at initial and decreases with time to approach the Hubble constant. The expansion velocity can be over the light speed in the early period, which decreases to the minimum at the turning point and then increases with time to approach the ratio of the present radius to the Hubble radius times the square root of the density parameter in dark energy. The solution of the time-dependent radius increases with time. The present time depends on the three key parameters. The universe with a larger present radius, smaller Hubble constant, or smaller density parameter in dark energy is elder. The universe with greater density parameter in dark energy accelerates faster recently. The open and closed universes can also be accelerated recently. The turning points and evolution characteristics among different types of the universe and different sets of key parameters are compared. This presentation will show the details, supported by NASA grant (NNG04GD59G).

  10. The expanding universe of thiolated gold nanoclusters and beyond.

    PubMed

    Jiang, De-en

    2013-08-21

    Thiolated gold nanoclusters form a universe of their own. Researchers in this field are constantly pushing the boundary of this universe by identifying new compositions and in a few "lucky" cases, solving their structures. Such solved structures, even if there are only few, provide important hints for predicting the many identified compositions that are yet to be crystallized or structure determined. Structure prediction is the most pressing issue for a computational chemist in this field. The success of the density functional theory method in gauging the energetic ordering of isomers for thiolated gold clusters has been truly remarkable, but to predict the most stable structure for a given composition remains a great challenge. In this feature article from a computational chemist's point of view, the author shows how one understands and predicts structures for thiolated gold nanoclusters based on his old and new results. To further entertain the reader, the author also offers several "imaginative" structures, claims, and challenges for this field.

  11. The expanding universe of thiolated gold nanoclusters and beyond

    NASA Astrophysics Data System (ADS)

    Jiang, De-En

    2013-07-01

    Thiolated gold nanoclusters form a universe of their own. Researchers in this field are constantly pushing the boundary of this universe by identifying new compositions and in a few ``lucky'' cases, solving their structures. Such solved structures, even if there are only few, provide important hints for predicting the many identified compositions that are yet to be crystallized or structure determined. Structure prediction is the most pressing issue for a computational chemist in this field. The success of the density functional theory method in gauging the energetic ordering of isomers for thiolated gold clusters has been truly remarkable, but to predict the most stable structure for a given composition remains a great challenge. In this feature article from a computational chemist's point of view, the author shows how one understands and predicts structures for thiolated gold nanoclusters based on his old and new results. To further entertain the reader, the author also offers several ``imaginative'' structures, claims, and challenges for this field.

  12. Functional diversification of Argonautes in nematodes: an expanding universe.

    PubMed

    Buck, Amy H; Blaxter, Mark

    2013-08-01

    In the last decade, many diverse RNAi (RNA interference) pathways have been discovered that mediate gene silencing at epigenetic, transcriptional and post-transcriptional levels. The diversity of RNAi pathways is inherently linked to the evolution of Ago (Argonaute) proteins, the central protein component of RISCs (RNA-induced silencing complexes). An increasing number of diverse Agos have been identified in different species. The functions of most of these proteins are not yet known, but they are generally assumed to play roles in development, genome stability and/or protection against viruses. Recent research in the nematode Caenorhabditis elegans has expanded the breadth of RNAi functions to include transgenerational epigenetic memory and, possibly, environmental sensing. These functions are inherently linked to the production of secondary siRNAs (small interfering RNAs) that bind to members of a clade of WAGOs (worm-specific Agos). In the present article, we review briefly what is known about the evolution and function of Ago proteins in eukaryotes, including the expansion of WAGOs in nematodes. We postulate that the rapid evolution of WAGOs enables the exceptional functional plasticity of nematodes, including their capacity for parasitism.

  13. Teaching and Research with Accelerators at Tarleton State University

    SciTech Connect

    Marble, Daniel K.

    2009-03-10

    Tarleton State University students began performing both research and laboratory experiments using accelerators in 1998 through visitation programs at the University of North Texas, US Army Research Laboratory, and the Naval Surface Warfare Center at Carderock. In 2003, Tarleton outfitted its new science building with a 1 MV pelletron that was donated by the California Institution of Technology. The accelerator has been upgraded and supports a wide range of classes for both the Physics program and the ABET accredited Engineering Physics program as well as supplying undergraduate research opportunities on campus. A discussion of various laboratory activities and research projects performed by Tarleton students will be presented.

  14. Gravity and count probabilities in an expanding universe

    NASA Technical Reports Server (NTRS)

    Bouchet, Francois R.; Hernquist, Lars

    1992-01-01

    The time evolution of nonlinear clustering on large scales in cold dark matter, hot dark matter, and white noise models of the universe is investigated using N-body simulations performed with a tree code. Count probabilities in cubic cells are determined as functions of the cell size and the clustering state (redshift), and comparisons are made with various theoretical models. We isolate the features that appear to be the result of gravitational instability, those that depend on the initial conditions, and those that are likely a consequence of numerical limitations. More specifically, we study the development of skewness, kurtosis, and the fifth moment in relation to variance, the dependence of the void probability on time as well as on sparseness of sampling, and the overall shape of the count probability distribution. Implications of our results for theoretical and observational studies are discussed.

  15. Positive Deviance during Organization Change: Researchers' Social Construction of Expanded University Goals

    ERIC Educational Resources Information Center

    Sutherland, Claire Euline

    2013-01-01

    Many universities have expanded from teaching only to include research goals, requiring shifts in organization behavior. An exploratory case study method was used to examine these dynamics among positive deviant researchers at the University of Technology, Jamaica (UTech), the single case examined, from a social construction perspective. As a…

  16. Fractal geometry in an expanding, one-dimensional, Newtonian universe.

    PubMed

    Miller, Bruce N; Rouet, Jean-Louis; Le Guirriec, Emmanuel

    2007-09-01

    Observations of galaxies over large distances reveal the possibility of a fractal distribution of their positions. The source of fractal behavior is the lack of a length scale in the two body gravitational interaction. However, even with new, larger, sample sizes from recent surveys, it is difficult to extract information concerning fractal properties with confidence. Similarly, three-dimensional N-body simulations with a billion particles only provide a thousand particles per dimension, far too small for accurate conclusions. With one-dimensional models these limitations can be overcome by carrying out simulations with on the order of a quarter of a million particles without compromising the computation of the gravitational force. Here the multifractal properties of two of these models that incorporate different features of the dynamical equations governing the evolution of a matter dominated universe are compared. For each model at least two scaling regions are identified. By employing criteria from dynamical systems theory it is shown that only one of them can be geometrically significant. The results share important similarities with galaxy observations, such as hierarchical clustering and apparent bifractal geometry. They also provide insights concerning possible constraints on length and time scales for fractal structure. They clearly demonstrate that fractal geometry evolves in the mu (position, velocity) space. The observed patterns are simply a shadow (projection) of higher-dimensional structure.

  17. Induced dark energy in a warped braneworld and accelerating universe

    NASA Astrophysics Data System (ADS)

    Lee, Tae Hoon

    2016-10-01

    In the six-dimensional (6D) Einstein gravity with a negative cosmological constant, we determine the structure of warped spacetimes bounded by 4-branes. We find an accelerating Universe solution with the induced dark energy, from the 4-brane obtained by orbifolding an external space, and suggest a possibility of addressing problems related to the cosmological constant.

  18. Explaining the accelerated expansion of the Universe by particle creation

    NASA Astrophysics Data System (ADS)

    Singh, Ibotombi N.; Devi, Bembem Y.

    2016-04-01

    A spatially flat FRW Universe in the context of particle creation has been discussed by assuming a variable deceleration parameter which is a function of scale factor. A dust model in which creation of particles giving a negative creation pressure has been studied. Treating the Universe as an open adiabatic system, it is supposed that matter creation takes place out of gravitational energy. In this model, the Universe shows an accelerating phase of its expansion. Total number of particles increases while number of particle density decreases. Some physical implications of this model are investigated.

  19. Accelerated expansion of the universe à la the Stueckelberg mechanism

    SciTech Connect

    Akarsu, Özgür; Arık, Metin; Katırcı, Nihan; Kavuk, Mehmet E-mail: metin.arik@boun.edu.tr E-mail: mehmet.kavuk@boun.edu.tr

    2014-07-01

    We investigate a cosmological model in which the Stueckelberg fields are non-minimally coupled to the scalar curvature in a gauge invariant manner. We present not only a solution that can be considered in the context of the late time acceleration of the universe but also a solution compatible with the inflationary cosmology. Distinct behaviors of the scalar and vector fields together with the real valued mass gained by the Stueckelberg mechanism lead the universe to go through the two different accelerated expansion phases with a decelerated expansion phase between them. On the other hand, in the solutions we present, if the mass is null then the universe is either static or exhibits a simple power law expansion due to the vector field potential.

  20. Possible geometrical origin of the accelerated expansion of the Universe

    NASA Astrophysics Data System (ADS)

    Montiel, Ariadna; Bretón, Nora; Cordero, Rubén; Rojas, Efraín

    2015-07-01

    The modified geodetic brane cosmology (MGBC) is tested with observational data. The MGBC is derived from the geodetic brane gravity action corrected by the extrinsic curvature of the braneworld. The density parameter coming from this additional term produces an accelerated expansion of geometrical origin. Subject to the supernovae Ia, observable Hubble parameter, baryon acoustic oscillations and cosmic microwave background probes, the obtained fit provides enough evidence in the sense that the extrinsic curvature effect is able to reproduce the accelerated expansion of the universe without the need for invoking dark energy, exotic matter or a cosmological constant. Moreover, the MGBC is free of the problems present in other braneworld models.

  1. On Escaping a Galaxy Cluster in an Accelerating Universe

    NASA Astrophysics Data System (ADS)

    Stark, Alejo; Miller, Christopher J.; Gifford, Daniel

    2016-10-01

    We derive the escape velocity profile for an Einasto density field in an accelerating universe and demonstrate its physical viability by comparing theoretical expectations to both light-cone data generated from N-body simulations and archival data on 20 galaxy clusters. We demonstrate that the projection function (g(β )) is deemed physically viable only for the theoretical expectation that includes a cosmology-dependent term. Using simulations, we show that the inferred velocity anisotropy is more than 6σ away from the expected value for the theoretical profile that ignores the acceleration of the universe. In the archival data, we constrain the average velocity anisotropy parameter of a sample of 20 clusters to be β ={0.248}-0.360+0.164 at the 68% confidence level. Lastly, we briefly discuss how our analytic model may be used as a novel cosmological probe based on galaxy clusters.

  2. National health expenditure projections: modest annual growth until coverage expands and economic growth accelerates.

    PubMed

    Keehan, Sean P; Cuckler, Gigi A; Sisko, Andrea M; Madison, Andrew J; Smith, Sheila D; Lizonitz, Joseph M; Poisal, John A; Wolfe, Christian J

    2012-07-01

    For 2011-13, US health spending is projected to grow at 4.0 percent, on average--slightly above the historically low growth rate of 3.8 percent in 2009. Preliminary data suggest that growth in consumers' use of health services remained slow in 2011, and this pattern is expected to continue this year and next. In 2014, health spending growth is expected to accelerate to 7.4 percent as the major coverage expansions from the Affordable Care Act begin. For 2011 through 2021, national health spending is projected to grow at an average rate of 5.7 percent annually, which would be 0.9 percentage point faster than the expected annual increase in the gross domestic product during this period. By 2021, federal, state, and local government health care spending is projected to be nearly 50 percent of national health expenditures, up from 46 percent in 2011, with federal spending accounting for about two-thirds of the total government share. Rising government spending on health care is expected to be driven by faster growth in Medicare enrollment, expanded Medicaid coverage, and the introduction of premium and cost-sharing subsidies for health insurance exchange plans. PMID:22692089

  3. National health expenditure projections: modest annual growth until coverage expands and economic growth accelerates.

    PubMed

    Keehan, Sean P; Cuckler, Gigi A; Sisko, Andrea M; Madison, Andrew J; Smith, Sheila D; Lizonitz, Joseph M; Poisal, John A; Wolfe, Christian J

    2012-07-01

    For 2011-13, US health spending is projected to grow at 4.0 percent, on average--slightly above the historically low growth rate of 3.8 percent in 2009. Preliminary data suggest that growth in consumers' use of health services remained slow in 2011, and this pattern is expected to continue this year and next. In 2014, health spending growth is expected to accelerate to 7.4 percent as the major coverage expansions from the Affordable Care Act begin. For 2011 through 2021, national health spending is projected to grow at an average rate of 5.7 percent annually, which would be 0.9 percentage point faster than the expected annual increase in the gross domestic product during this period. By 2021, federal, state, and local government health care spending is projected to be nearly 50 percent of national health expenditures, up from 46 percent in 2011, with federal spending accounting for about two-thirds of the total government share. Rising government spending on health care is expected to be driven by faster growth in Medicare enrollment, expanded Medicaid coverage, and the introduction of premium and cost-sharing subsidies for health insurance exchange plans.

  4. Ghosts in the self-accelerating brane universe

    NASA Astrophysics Data System (ADS)

    Koyama, Kazuya

    2005-12-01

    We study the spectrum of gravitational perturbations about a vacuum de Sitter brane with the induced 4D Einstein-Hilbert term, in a 5D Minkowski spacetime (DGP model). We consider solutions that include a self-accelerating universe, where the accelerating expansion of the universe is realized without introducing a cosmological constant on the brane. The mass of the discrete mode for the spin-2 graviton is calculated for various Hrc, where H is the Hubble parameter and rc is the crossover scale determined by the ratio between the 5D Newton constant and the 4D Newton constant. We show that, if we introduce a positive cosmological constant on the brane (Hrc>1), the spin-2 graviton has mass in the range 01/2. In a self-accelerating universe Hrc=1, the spin-2 graviton has mass m2=2H2, which coincides with the mass of the brane fluctuation mode. Then there arises a mixing between the brane fluctuation mode and the spin-2 graviton. We argue that this mixing presumably gives a ghost in the self-accelerating universe by continuity across Hrc=1, although a careful calculation of the effective action is required to verify this rigorously.

  5. When can an "Expanding Universe" look "Static" and vice versa: A comprehensive study

    NASA Astrophysics Data System (ADS)

    Mitra, Abhas

    2015-02-01

    The Friedmann-Robertson-Walker (FRW) metric expressed, in terms of comoving coordinates (r, t), always looks nonstatic. But by employing the recently derived curvature/Schwarzschild form, (R, T), of FRW metric (A. Mitra, Gravit. Cosmol. 19 (2013) 134), we show here that FRW metric can assume static forms when the net energy density (ρe) is solely due to the vacuum contribution. Earlier this question was explored by Florides (Gen. Relativ. Gravit. 12 (1980) 563) whose approach was complex and of purely mathematical nature. Also, unlike Florides, we do not assume any a priori separability of T(r, t) = F(r)G(t) and thus our treatment is truly general and yet simpler. More interestingly, even if the net energy density involved in a certain FRW model may appear to be nonzero from its algebric appearance, it may still be possible that tacitly ρe = 0 and the model actually corresponds to a vacuum Minkowski metric. For instance, it has been found that FRW universes which appear to be expanding with a fixed speed in comoving coordinates are intrinsically static universes. While such a linearly expanding universe having k = -1 is well-known as the Milne universe, the corresponding k = 0 case has recently been shown to be vacuum in disguise (A. Mitra, Mon. Not. Roy. Astron. Soc. 442 (2014) 382). In addition, here we show that even the k = +1 linearly "expanding" universe (in comoving coordinates) tacitly corresponds to Einstein's static universe.

  6. Cylindrical gravitational waves in expanding universes: Models for waves from compact sources

    SciTech Connect

    Gowdy, Robert H.; Edmonds, B. Douglas

    2007-04-15

    New boundary conditions are imposed on the familiar cylindrical gravitational wave vacuum spacetimes. The new spacetime family represents cylindrical waves in a flat expanding (Kasner) universe. Space sections are flat and nonconical where the waves have not reached and wave amplitudes fall off more rapidly than they do in Einstein-Rosen solutions, permitting a more regular null inifinity.

  7. The Great Attractor: At the Limits of Hubble's Law of the Expanding Universe.

    ERIC Educational Resources Information Center

    Murdin, Paul

    1991-01-01

    Presents the origin and mathematics of Hubble's Law of the expanding universe. Discusses limitations to this law and the related concepts of standard candles, elliptical galaxies, and streaming motions, which are conspicuous deviations from the law. The third of three models proposed as explanations for streaming motions is designated: The Great…

  8. Space and Dollars--An Urban University Expands. Case Studies of Educational Facilities, Number 2.

    ERIC Educational Resources Information Center

    Weinstock, Ruth

    Using Drexel Institute of Philadelphia as a case study, Educational Facilities Laboratories investigated six areas of inquiry facing an urban university contemplating expansion--(1) economics of high-rise building, (2) economics of constructing low building units which can be vertically expanded at a later date, (3) conversion of industrial…

  9. SPACE AND DOLLARS--AN URBAN UNIVERSITY EXPANDS. CASE STUDIES OF EDUCATIONAL FACILITIES, NUMBER 2.

    ERIC Educational Resources Information Center

    WEINSTOCK, RUTH

    USING DREXEL INSTITUTE OF PHILADELPHIA AS A CASE STUDY, EDUCATIONAL FACILITIES LABORATORIES INVESTIGATED SIX AREAS OF INQUIRY FACING AN URBAN UNIVERSITY CONTEMPLATING EXPANSION--(1) THE ECONOMICS OF THE HIGH-RISE BUILDING, (2) THE ECONOMICS OF CONSTRUCTING LOW BUILDING UNITS WHICH CAN BE VERTICALLY EXPANDED AT A LATER DATE, (3) THE CONVERSION OF…

  10. The Expanded Developmental Periphery: Framing the Institutional Role of University Continuing Education Units

    ERIC Educational Resources Information Center

    Fleming, Josephine

    2013-01-01

    This article argues that Burton Clark's notion of the expanded developmental periphery provides a useful conceptual framework for examining the differing relationships between continuing and professional education units and the institutional core of traditional research universities. The intent is to examine how Clark's notion offers a…

  11. Expanding Peatlands in Alaska Caused by Accelerated Glacier Melting Under a Warming Climate

    NASA Astrophysics Data System (ADS)

    Loisel, J.; Yu, Z.; Jones, M. C.

    2009-05-01

    Most mountain glaciers worldwide have been retreating over the last century due to global warming. This is particularly true around the Gulf of Alaska, where glacier recession has further accelerated since 1988. It is well known that glacier meltwater plays a critical role in the global sea level rise, but its effects on structure and functioning of peatland ecosystems remain poorly understood. We have observed in the field that many peatlands in the Susitna Basin, south-central Alaska, are expanding. As high moisture conditions are needed to promote peatland development and expansion, a regional change toward wetter conditions is likely responsible for the ongoing paludification of these peatlands. However, instrumental climatic data from this region show no increase in precipitation but an increase in temperature (and presumably evaporation) over the last decades. We hypothesize that climatically-induced glacier melting is modifying the local/regional climate, especially air humidity during the growing season, promoting the expansion of peatlands. To document recent peatland vertical growth and lateral expansion, we collected two long peat cores and twelve 30-cm-long monoliths in 2008 along a 110-m transect from an expanding peatland margin toward the peatland center. Ecohydrologic changes were reconstructed from testate amoebae and plant macrofossils assemblages. Preliminary results from both long cores revealed a change in the vegetation assemblages from a mesotrophic fen dominated by sedges and brown mosses to a Sphagnum-dominated peat bog at 11 cm, suggesting a very recent modification of the local hydrologic regime. A simultaneous increase in moisture was reconstructed from testate amoebae records. These unusual shifts in peatland development and hydrology (e.g., wet conditions triggering the fen-bog transition) imply a recent increase of atmospheric water to these peatlands. Our ongoing lead-210 dating and additional proxy analysis will help us resolve the

  12. The Mysterious Universe - Exploring Our World with Particle Accelerators

    SciTech Connect

    Brau, James E

    2010-11-23

    The universe is dark and mysterious, more so than even Einstein imagined. While modern science has established deep understanding of ordinary matter, unidentified elements ("Dark Matter" and "Dark Energy") dominate the structure of the universe, its behavior and its destiny. What are these curious elements? We are now working on answers to these and other challenging questions posed by the universe with experiments at particle accelerators on Earth. Results of this research may revolutionize our view of nature as dramatically as the advances of Einstein and other quantum pioneers one hundred years ago. Professor Brau will explain for the general audience the mysteries, introduce facilities which explore them experimentally and discuss our current understanding of the underlying science. The presentation is at an introductory level, appropriate for anyone interested in physics and astronomy.

  13. The Mysterious Universe - Exploring Our World with Particle Accelerators

    ScienceCinema

    Brau, James E [University of Oregon

    2016-07-12

    The universe is dark and mysterious, more so than even Einstein imagined. While modern science has established deep understanding of ordinary matter, unidentified elements ("Dark Matter" and "Dark Energy") dominate the structure of the universe, its behavior and its destiny. What are these curious elements? We are now working on answers to these and other challenging questions posed by the universe with experiments at particle accelerators on Earth. Results of this research may revolutionize our view of nature as dramatically as the advances of Einstein and other quantum pioneers one hundred years ago. Professor Brau will explain for the general audience the mysteries, introduce facilities which explore them experimentally and discuss our current understanding of the underlying science. The presentation is at an introductory level, appropriate for anyone interested in physics and astronomy.

  14. Nonlinear electromagnetic fields as a source of universe acceleration

    NASA Astrophysics Data System (ADS)

    Kruglov, S. I.

    2016-04-01

    A model of nonlinear electromagnetic fields with a dimensional parameter β is proposed. From PVLAS experiment the bound on the parameter β was obtained. Electromagnetic fields are coupled with the gravitation field and we show that the universe accelerates due to nonlinear electromagnetic fields. The magnetic universe is considered and the stochastic magnetic field is a background. After inflation the universe decelerates and approaches to the radiation era. The range of the scale factor, when the causality of the model and a classical stability take place, was obtained. The spectral index, the tensor-to-scalar ratio, and the running of the spectral index were estimated which are in approximate agreement with the Planck, WMAP, and BICEP2 data.

  15. Universality of the acceleration due to gravity on the surface of a rapidly rotating neutron star

    SciTech Connect

    AlGendy, Mohammad; Morsink, Sharon M.

    2014-08-20

    On the surface of a rapidly rotating neutron star, the effective centrifugal force decreases the effective acceleration due to gravity (as measured in the rotating frame) at the equator while increasing the acceleration at the poles due to the centrifugal flattening of the star into an oblate spheroid. We compute the effective gravitational acceleration for relativistic rapidly rotating neutron stars and show that for a star with mass M, equatorial radius R{sub e} , and angular velocity Ω, the deviations of the effective acceleration due to gravity from the nonrotating case take on a universal form that depends only on the compactness ratio M/R{sub e} , the dimensionless square of the angular velocity Ω{sup 2}R{sub e}{sup 3}/GM, and the latitude on the star's surface. This dependence is universal, in that it has very little dependence on the neutron star's equation of state. The effective gravity is expanded in the slow-rotation limit to show the dependence on the effective centrifugal force, oblate shape of the star, and the quadrupole moment of the gravitational field. In addition, an empirical fit and simple formula for the effective gravity is found. We find that the increase in the acceleration due to gravity at the poles is of the same order of magnitude as the decrease in the effective acceleration due to gravity at the equator for all realistic value of mass, radius, and spin. For neutron stars that spin with frequencies near 600 Hz, the difference between the effective gravity at the poles and the equator is about 20%.

  16. Bulk viscous matter and recent acceleration of the universe

    NASA Astrophysics Data System (ADS)

    Sasidharan, Athira; Mathew, Titus K.

    2015-07-01

    We consider a cosmological model dominated by bulk viscous matter with a total bulk viscosity coefficient proportional to the velocity and acceleration of the expansion of the universe in such a way that We show that there exist two limiting conditions in the bulk viscous coefficients (, , ) which correspond to a universe having a Big Bang at the origin, followed by an early decelerated epoch and then making a smooth transition into an accelerating epoch. We have constrained the model using the type Ia Supernovae data, evaluated the best estimated values of all the bulk viscous parameters and the Hubble parameter corresponding to the two limiting conditions. We found that even though the evolution of the cosmological parameters are in general different for the two limiting cases, they show identical behavior for the best estimated values of the parameters from both limiting conditions. A recent acceleration would occur if for the first limiting conditions and if for the second limiting conditions. The age of the universe predicted by this model is found to be less than that predicted from the oldest galactic globular clusters. The total bulk viscosity seems to be negative in the past and becomes positive when . So the model violates the local second law of thermodynamics. However, the model satisfies the generalized second law of thermodynamics at the apparent horizon throughout the evolution of the universe. We also made a statefinder analysis of the model and found that it is distinguishably different from the standard CDM model at present, but it shows a de Sitter type behavior in the far future of the evolution.

  17. Cosmic Acceleration in the Early and Present Universe

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Masahide

    Cosmic accelerations in the early and present Universe play essentially important roles to determine the evolution, structure, and destiny of the Universe. Therefore, to identify the origins of cosmic accelerations is one of the most ultimate goals of cosmology. In this award talk for the C. N. Yang Award, I introduced my achievements on this mystery. First of all, we gave a natural mechanism to cause chaotic inflation, which is the most natural inflation model but had never been realized in the context of realistic particle physics for almost twenty years. We introduced a Nambu-Goldstone-like shift symmetry, which is now recognized as a key feature to control the Planck-scale physics, and solved the long standing difficulties to realize chaotic inflation. Second, we found a generic relation (now called Suyama-Yamaguchi inequality) between higher order correlations of the curvature perturbations, which is quite useful to identify what fields are actually responsible for the origin of primordial fluctuation. Finally, we mention our proposal (now called k-essence) for the present cosmic acceleration.

  18. Technical assessment of the Loma Linda University proton therapy accelerator

    SciTech Connect

    Not Available

    1989-10-01

    In April 1986, officials of Loma Linda University requested that Fermilab design and construct a 250 MeV proton synchrotron for radiotherapy, to be located at the Loma Linda University Medical Center. In June 1986 the project, having received all necessary approvals, commenced. In order to meet a desirable schedule providing for operation in early 1990, it was decided to erect such parts of the accelerator as were complete at Fermilab and conduct a precommissioning activity prior to the completion of the building at Loma Linda which will house the final radiotherapy facility. It was hoped that approximately one year would be saved by the precommissioning, and that important information would be obtained about the system so that improvements could be made during installation at Loma Linda. This report contains an analysis by Fermilab staff members of the information gained in the precommissioning activity and makes recommendations about steps to be taken to enhance the performance of the proton synchrotron at Loma Linda. In the design of the accelerator, effort was made to employ commercially available components, or to industrialize the products developed so that later versions of the accelerator could be produced industrially. The magnets could only be fabricated at Fermilab if the schedule was to be met, but efforts were made to transfer that technology to industry. Originally, it was planned to use a 1.7 MeV RFQ fabricated at the Lawrence Berkeley Laboratory as injector, but LBL would have found it difficult to meet the project schedule. After consideration of other options, for example a 3.4 MeV tandem accelerator, a supplier (AccSys Inc.) qualified itself to provide a 2 MeV RFQ on a schedule well matched to the project schedule. This choice was made, but a separate supplier was selected to develop and provide the 425 MHz power amplifier for the RFQ.

  19. COBRA accelerator for Sandia ICF diode research at Cornell University

    SciTech Connect

    Smith, D.L.; Ingwersen, P.; Bennett, L.F.; Boyes, J.D.; Anderson, D.E.; Greenly, J.B.; Sudan, R.N.

    1995-05-01

    The new COBRA accelerator is being built in stages at the Laboratory of Plasma Studies in Cornell University where its applications will include extraction diode and ion beam research in support of the light ion inertial confinement fusion (ICF) program at Sandia National Laboratories. The 4- to 5-MV, 125- to 250-kA accelerator is based on a four-cavity inductive voltage adder (IVA) design. It is a combination of new ferromagnetically-isolated cavities and self magnetically insulated transmission line (MITL) hardware and components from existing Sandia and Cornell facilities: Marx generator capacitors, hardware, and power supply from the DEMON facility; water pulse forming lines (PFL) and gas switch from the Subsystem Test Facility (STF); a HERMES-III intermediate store capacitor (ISC); and a modified ion diode from Cornell`s LION. The present accelerator consists of a single modified cavity similar to those of the Sandia SABRE accelerator and will be used to establish an operating system for the first stage initial lower voltage testing. Four new cavities will be fabricated and delivered in the first half of FY96 to complete the COBRA accelerator. COBRA is unique in the sense that each cavity is driven by a single pulse forming line, and the IVA output polarity may be reversed by rotating the cavities 180{degrees} about their vertical axis. The site preparations, tank construction, and diode design and development are taking place at Cornell with growing enthusiasm as this machine becomes a reality. Preliminary results with the single cavity and short positive inner cylinder MITL configuration will soon be available.

  20. A Fine-Tooth Comb to Measure the Accelerating Universe

    NASA Astrophysics Data System (ADS)

    2008-09-01

    Astronomical instruments needed to answer crucial questions, such as the search for Earth-like planets or the way the Universe expands, have come a step closer with the first demonstration at the telescope of a new calibration system for precise spectrographs. The method uses a Nobel Prize-winning technology called a 'laser frequency comb', and is published in this week's issue of Science. Uncovering the disc ESO PR Photo 26a/08 A Laser Comb for Astronomy "It looks as if we are on the way to fulfil one of astronomers' dreams," says team member Theodor Hänsch, director at the Max Planck Institute for Quantum Optics (MPQ) in Germany. Hänsch, together with John Hall, was awarded the 2005 Nobel Prize in Physics for work including the frequency comb technique. Astronomers use instruments called spectrographs to spread the light from celestial objects into its component colours, or frequencies, in the same way water droplets create a rainbow from sunlight. They can then measure the velocities of stars, galaxies and quasars, search for planets around other stars, or study the expansion of the Universe. A spectrograph must be accurately calibrated so that the frequencies of light can be correctly measured. This is similar to how we need accurate rulers to measure lengths correctly. In the present case, a laser provides a sort of ruler, for measuring colours rather than distances, with an extremely accurate and fine grid. New, extremely precise spectrographs will be needed in experiments planned for the future European Extremely Large Telescope (E-ELT), which is being designed by ESO, the European Southern Observatory. These new spectrographs will need to be calibrated with even more accurate 'rulers'. In fact, they must be accurate to about one part in 30 billions - a feat equivalent to measuring the circumference of the Earth to about a millimetre! "We'll need something beyond what current technology can offer, and that's where the laser frequency comb comes in. It is

  1. University programs of the U.S. Department of Energy advanced accelerator applications program

    SciTech Connect

    Beller, D. E.; Ward, T. E.; Bresee, J. C.

    2001-01-01

    The Advanced Accelerator Applications (AAA) Program was initiated in fiscal year 2001 (FY-01) by the U.S. Congress, the U.S. Department of Energy (DOE), and the Los Alamos National Laboratory (LANL) in partnership with other national laboratories. The primary goal of this program is to investigate the feasibility of transmutation of nuclear waste. An Accelerator-Driven Test Facility (ADTF), which may be built during the first decade of the 21st Century, is a major component of this effort. The ADTF would include a large, state-of-the-art charged-particle accelerator, proton-neutron target systems, and accelerator-driven R&D systems. This new facility and its underlying science and technology will require a large cadre of educated scientists and trained technicians. In addition, other applications of nuclear science and engineering (e.g., proliferation monitoring and defense, nuclear medicine, safety regulation, industrial processes, and many others) require increased academic and national infrastructure and student populations. Thus, the AAA Program Office has begun a multi-year program to involve university faculty and students in various phases of the Project to support the infrastructure requirements of nuclear energy, science and technology fields as well as the special needs of the DOE transmutation program. In this paper we describe university programs that have supported, are supporting, and will support the R&D necessary for the AAA Project. Previous work included research for the Accelerator Transmutation of Waste (ATW) project, current (FY-01) programs include graduate fellowships and research for the AAA Project, and it is expected that future programs will expand and add to the existing programs.

  2. Einstein’s Legacy to Astronomy: From Black Holes to the Expanding Universe

    NASA Astrophysics Data System (ADS)

    Bartusiak, Marcia

    2006-12-01

    Albert Einstein placed a formidable imprint on astronomy. Not since the time of Isaac Newton, three centuries ago, has a single individual so influenced the field. Many of the great astronomical findings of the 20th century--the expanding universe, compact stars, origin of the Sun’s power, black holes, gravitational lensing, dark energy, gravity waves--are rooted in the physics that Einstein so brilliantly deduced. This illustrated presentation, the Gemant Award Lecture sponsored by the American Institute of Physics, will provide a guided tour through the cosmos and explain how our understanding of the universe was transformed by Einstein’s theories of special and general relativity.

  3. The magnetized universe: its origin and dissipation through acceleration

    SciTech Connect

    Colgate, Stirling; Li, Hui; Kronberg, Philip

    2010-09-02

    Problems of a magnetic universe and some, possible solutions: The greater the total energy of an astrophysical phenomena, the more restricted are the possible explanations. Magnetic energy is the most challenging because its origin is still considered problematic. We suggest that it is evident that the universe is magnetized because of radio lobes, extra galactic cosmic rays, an observed Faraday rotation measure, and the polarized emission of extra galactic radio structures. The implied energies are so large that only the formation of supermassive black holes, (SMBHs) at the center of every galaxy are remotely energetic enough to supply this immense energy, {approx} (1/10)10{sup 8} M{sub {circle_dot}}c{sup 2}. (Only a galaxy cluster of 1000 galaxies has comparable energy, but is inversely rare.) Yet this energy appears to be largely transformed into accelerated relativistic particles, both electrons and ions. Only a large-scale coherent dynamo within the accretion disk forming the massive black hole makes a reasonable starting point. The subsequent winding of this dynamo derived flux by conducting, angular-momentum-dominated accreting matter produces the immense, coherent magnetic fluxes. We imbed this explanation in a list of similar phenomena at smaller scale and look for physical consistency among the various phenomena, especially the conversion of force-free magnetic energy into acceleration.

  4. Unemployment, Entrepreneurial Education and Mega Universities: Challenges to Expanding Access in Education in Nigeria University

    ERIC Educational Resources Information Center

    Undie, John Atewhoble; Okafor, Victor

    2014-01-01

    In fundamental economics, individuals acquired education for two broad reasons, as an investment and as consumption. The investment function of education has continued to create tension for job search leading to cases of unemployment. Entrepreneurship education and establishment of mega universities have been identified as panaceas. This paper…

  5. The Day We Found the Universe: The Little-Known History of How We Came to Understand the Expanding Universe

    NASA Astrophysics Data System (ADS)

    Bartusiak, M.

    2011-09-01

    This will be an overview of the birth of modern cosmology in the 1920s, when the true nature and startling size of the universe was at last revealed. While today Edwin Hubble gets most of the credit, the story is far more complex, involving battles of wills, clever insights, and wrong turns made by a number of investigators before Hubble. The Hubble Space Telescope could easily have had another name if certain events had turned out differently: if Lick Observatory director James Keeler had not prematurely died in 1900 and solved the mystery of the spiral nebulae years earlier; if Lick astronomer Heber Curtis had not taken a promotion in 1920, taking him out of the game; or if astronomer Harlow Shapley, Hubble's nemesis, was not mulishly wedded to a flawed vision of the cosmos. Half the work to prove the universe was expanding was actually performed by Lowell Observatory astronomer Vesto Slipher; Hubble used Slipher's data in 1929 to establish what came to be known as the Hubble Law without citation or acknowledgment, a serious breach of scientific protocol. Even then, Hubble was never a vocal champion of the idea that the universe was expanding. Hubble always coveted an unblemished record: the perfect wife, the perfect scientific findings, the perfect friends. Throughout his life, Hubble claimed that the galaxies fleeing outward were apparent velocities. He wanted to protect his legacy in case a new law of physics was revealed that changed that explanation.

  6. Expanding Gravity

    NASA Astrophysics Data System (ADS)

    Aisenberg, Sol

    2005-04-01

    Newton's gravitational constant Gn and Laws of Gravity are based upon observations in our solar system. Mysteries appear when they are used far outside our solar system Apparently, Newton's gravitational constant can not be applied at large distances. Dark matter was needed to explain the observed flat rotational velocity curves of spiral galaxies (Rubin), and of groups of remote galaxies (Zwicky). Our expansion of Newton's gravitational constant Gn as a power series in distance r, is sufficient to explain these observations without using dark matter. This is different from the MOND theory of Milgrom involving acceleration. Also, our Expanded Gravitational Constant (EGC) can show the correct use of the red shift. In addition to the Doppler contribution, there are three other contributions and these depend only upon gravity. Thus, velocity observations only based on the red shift can not be used to support the concept of the expanding universe, the accelerating expansion, or dark energy. Our expanded gravity constant can predict and explain Olbers' paradox (dark sky), and the temperature of the CMB (cosmic microwave background). Thus, CMB may not support the big bang and inflation.

  7. Activities of the Tandem Accelerator Center, University of Tsukuba

    NASA Astrophysics Data System (ADS)

    1993-10-01

    This annual report includes the research activities and the technical developments carried out at the Tandem Accelerator Center in University of Tsukuba for the period from April 1992 to March 1993. New experimental investigations were made on (1) nuclear spectroscopy was initiated by a new (gamma) ray spectrometer; (2) polarization phenomena in nuclear reactions; (3) the application of energetic heavy ions to solid state physics; (4) the behavior of self interstitial atoms and its migration mechanism in Mo metal; (5) the studies on electronic conduction of metal oxides and bronzes by NMR; (6) Moessbauer studies on Fe-Cr alloy and the RBS analysis of YBCO superconductor films; and (7) a new field was challenged on the micro cluster physics. Nuclear collective motion and the relativistic mean-field theory is also included in this report.

  8. Lilienfeld Prize Lecture: Life, The Universe, and Nothing: Life and Death in an Ever-Expanding Universe

    NASA Astrophysics Data System (ADS)

    Krauss, Lawrence M.

    2001-04-01

    In this talk, I will ruminate on the future of the Universe, and also on the future of life within it, using as my starting point recent observations in cosmology that have changed the way we think about the Universe on large scales. I will briefly review these observations and then discuss why the Universe we appear to inhabit may be the worst of all possible universes, as far as the long-term quality and quantity of life is concerned. Then, I will describe how fundamental aspects of the way in which we teach cosmology, in particular the relation between geometry and destiny, have been altered by the recognition that the cosmological constant may be zero. Finally, I will introduce the fascinating, if somewhat academic question of whether life can be eternal in an eternally expanding universe. Surprisingly, perhaps, the answer to this question appears to hinge on issues of basic physics, in particular on issues of quantum mechanics and computation, which may determine whether life is ultimately analogue or digital.

  9. Expanding the universe of universal coverage: the population health argument for increasing coverage for immigrants.

    PubMed

    Nandi, Arijit; Loue, Sana; Galea, Sandro

    2009-12-01

    As the US recession deepens, furthering the debate about healthcare reform is now even more important than ever. Few plans aimed at facilitating universal coverage make any mention of increasing access for uninsured non-citizens living in the US, many of whom are legally restricted from certain types of coverage. We conducted a critical review of the public health literature concerning the health status and access to health services among immigrant populations in the US. Using examples from infectious and chronic disease epidemiology, we argue that access to health services is at the intersection of the health of uninsured immigrants and the general population and that extending access to healthcare to all residents of the US, including undocumented immigrants, is beneficial from a population health perspective. Furthermore, from a health economics perspective, increasing access to care for immigrant populations may actually reduce net costs by increasing primary prevention and reducing the emphasis on emergency care for preventable conditions. It is unlikely that proposals for universal coverage will accomplish their objectives of improving population health and reducing social disparities in health if they do not address the substantial proportion of uninsured non-citizens living in the US.

  10. Can-AMS: The New Accelerator Mass Spectrometry Facility At The University Of Ottawa

    SciTech Connect

    Kieser, W. E.; Zhao, X.-L.; Clark, I. D.; Kotzer, T.; Litherland, A. E.

    2011-06-01

    The Canadian Centre for Accelerator Mass Spectrometry (AMS) at the University of Ottawa will be equipped with a new, 3 MV tandem accelerator with peripheral equipment for the analysis of elements ranging from tritium to the actinides. This facility, along with a wide array of support instrumentation recently funded by the Canada Foundation for Innovation, will be located in a new science building on the downtown campus of the University of Ottawa. In addition to providing the standard AMS measurements on {sup 14}C, {sup 10}Be, {sup 26}Al, {sup 36}Cl and {sup 129}I for earth, environmental, cultural and biomedical sciences, this facility will incorporate the new technologies of anion isobar separation at low energies using RFQ chemical reaction cells for {sup 36}Cl and new heavy element applications, integrated sample combustion and gas ion source for biomedical and environmental {sup 14}C analysis and the use of novel target matrices for expanding the range of applicable elements and simplifying sample preparation, all currently being developed at IsoTrace. This paper will outline the design goals for the new facility, present some details of the new AMS technologies, in particular the Isobar Separator for Anions and discuss the design of the AMS system resulting from these requirements.

  11. Expanding Research Capacity at United States Universities: A Study of Academic Research and Development Investment from 1990-2005

    ERIC Educational Resources Information Center

    Cantwell, Brendan; Mathies, Charles F.

    2012-01-01

    Growing emphasis has been placed on universities to contribute to the innovation process and as a result academic research and development expenditures have increased in recent years. Nevertheless, little is known about the specific ways in which universities have expanded their research capacity. This paper examines how universities in the United…

  12. Professional Development in the International Year of Astronomy: Expanding the Universe in the Classroom

    NASA Astrophysics Data System (ADS)

    Reinfeld, Erika L.; Harman, P.; Lee, M. H.; Bailey, J. M.

    2008-05-01

    The International Year of Astronomy offers unparalleled opportunity to expand our audiences’ understanding about the universe. However, many learners, students and adults alike, are unfamiliar with the universe beyond the solar system. This collaborative workshop explores strategies for teacher professional development around the origin and evolution of the universe, using the resources of the Beyond the Solar System Professional Development Project as a guide. The Beyond the Solar System (BtSS) Professional Development Project is a NASA-supported initiative from the Harvard-Smithsonian Center for Astrophysics (CfA) designed to foster public understanding of NASA's exciting astronomy and space science research. The BtSS portfolio includes video resources, assessment tools, data about common student ideas, content presentations, online telescope investigations, and other classroom activities designed to deepen content knowledge and improve the quality of teaching and learning about current scientific models and evidence for the origin and evolution of our universe of galaxies. During this session, members of the BtSS Leadership Team from around the country will share their experience using these resources in educator workshops and teacher-training courses, and facilitate discussions among workshop participants about how these materials and pedagogical strategies can be used in their own professional development efforts during the International Year of Astronomy. EPO specialists and scientists will engage in focused exploration of the project's DVD--"Expanding the Universe in the Classroom"--in order make explicit connections between the themes of the International Year of Astronomy and their own work. The goals of this workshop are to equip professional development providers to support IYA education efforts in classrooms, afterschool programs, and informal education venues and to raise awareness about the opportunities for continuing Galileo's legacy of discovery

  13. Creation of quantized particles, gravitons, and scalar perturbations by the expanding universe

    NASA Astrophysics Data System (ADS)

    Parker, Leonard

    2015-04-01

    Quantum creation processes during the very rapid early expansion of the universe are believed to give rise to temperature anisotropies and polarization patterns in the CMB radiation. These have been observed by satellites such as COBE, WMAP, and PLANCK, and by bolometric instruments placed near the South Pole by the BICEP collaborations. The expected temperature anisotropies are well-confirmed. The B-mode polarization patterns in the CMB are currently under measurement jointly by the PLANCK and BICEP groups to determine the extent to which the B-modes can be attributed to gravitational waves from the creation of gravitons in the earliest universe. As the original discoverer of the quantum phenomenon of particle creation from vacuum by the expansion of the universe, I will explain how the discovery came about and how it relates to the current observations. The first system that I considered when I started my Ph.D. thesis in 1962 was the quantized minimally-coupled scalar field in an expanding FLRW (Friedmann, Lemaitré, Robertson, Walker) universe having a general continuous scale factor a(t) with continuous time derivatives. I also considered quantized fermion fields of spin-1/2 and the spin-1 massless photon field, as well as the quantized conformally-invariant field equations of arbitrary integer and half-integer spins that had been written down in the classical context for general gravitational metrics by Penrose. It was during 1962 that I proved that quanta of the minimally-coupled scalar field were created by the general expanding FLRW universe. This was relevant also to the creation of quantized perturbations of the gravitational field, since these perturbations satisfied linear field equations that could be quantized in the same way as the minimally-coupled scalar field equation. In fact, in 1946, E.M. Lifshitz had considered the classical Einstein gravitational field in FLRW expanding universes and had shown that the classical linearized Einstein field

  14. Entanglement of a coarse grained quantum field in the expanding universe

    SciTech Connect

    Nambu, Yasusada; Ohsumi, Yuji

    2009-12-15

    We investigate the entanglement of a quantum field in the expanding universe. By introducing a bipartite system using a coarse-grained scalar field, we apply the separability criterion based on the partial transpose operation and numerically calculate the bipartite entanglement between separate spatial regions. We find that the initial entangled state becomes separable or disentangled after the spatial separation of two points exceed the Hubble horizon. This provides the necessary conditions for the appearance of classicality of the quantum fluctuation. We also investigate the condition of classicality that the quantum field can be treated as the classical stochastic variables.

  15. On propagation of electromagnetic and gravitational waves in the expanding Universe

    NASA Astrophysics Data System (ADS)

    Gladyshev, V. O.

    2016-07-01

    The purpose of this study was to obtain an equation for the propagation time of electromagnetic and gravitational waves in the expanding Universe. The velocity of electromagnetic waves propagation depends on the velocity of the interstellar medium in the observer's frame of reference. Gravitational radiation interacts weakly with the substance, so electromagnetic and gravitational waves propagate from a remote astrophysical object to the terrestrial observer at different time. Gravitational waves registration enables the inverse problem solution - by the difference in arrival time of electromagnetic and gravitational-wave signal, we can determine the characteristics of the emitting area of the astrophysical object.

  16. PARTICLE ACCELERATION IN THE EXPANDING BLAST WAVE OF {eta} CARINA'S GREAT ERUPTION OF 1843

    SciTech Connect

    Ohm, S.; Domainko, W.; Hinton, J. A. E-mail: wilfried.domainko@mpi-hd.mpg.d

    2010-08-01

    Non-thermal hard X-ray and high-energy (HE; 1 MeV {<=} E {<=} 100 GeV) {gamma}-ray emission in the direction of {eta} Carina has been recently detected using the INTEGRAL, AGILE, and Fermi satellites. So far this emission has been interpreted in the framework of particle acceleration in the colliding wind region between the two massive stars. However, the existence of a very fast moving blast wave which originates in the historical 1843 'Great Eruption' provides an alternative particle acceleration site in this system. Here, we explore an alternate scenario and find that inverse Compton emission from electrons accelerated in the blast wave can naturally explain both the flux and spectral shape of the measured hard X-ray and HE {gamma}-ray emission. This scenario is further supported by the lack of significant variability in the INTEGRAL and Fermi measured fluxes.

  17. The Universal Protein Resource (UniProt): an expanding universe of protein information.

    PubMed

    Wu, Cathy H; Apweiler, Rolf; Bairoch, Amos; Natale, Darren A; Barker, Winona C; Boeckmann, Brigitte; Ferro, Serenella; Gasteiger, Elisabeth; Huang, Hongzhan; Lopez, Rodrigo; Magrane, Michele; Martin, Maria J; Mazumder, Raja; O'Donovan, Claire; Redaschi, Nicole; Suzek, Baris

    2006-01-01

    The Universal Protein Resource (UniProt) provides a central resource on protein sequences and functional annotation with three database components, each addressing a key need in protein bioinformatics. The UniProt Knowledgebase (UniProtKB), comprising the manually annotated UniProtKB/Swiss-Prot section and the automatically annotated UniProtKB/TrEMBL section, is the preeminent storehouse of protein annotation. The extensive cross-references, functional and feature annotations and literature-based evidence attribution enable scientists to analyse proteins and query across databases. The UniProt Reference Clusters (UniRef) speed similarity searches via sequence space compression by merging sequences that are 100% (UniRef100), 90% (UniRef90) or 50% (UniRef50) identical. Finally, the UniProt Archive (UniParc) stores all publicly available protein sequences, containing the history of sequence data with links to the source databases. UniProt databases continue to grow in size and in availability of information. Recent and upcoming changes to database contents, formats, controlled vocabularies and services are described. New download availability includes all major releases of UniProtKB, sequence collections by taxonomic division and complete proteomes. A bibliography mapping service has been added, and an ID mapping service will be available soon. UniProt databases can be accessed online at http://www.uniprot.org or downloaded at ftp://ftp.uniprot.org/pub/databases/.

  18. Expanding a flutter envelope using data from accelerating flight: Application to the F-16 fighter aircraft

    NASA Astrophysics Data System (ADS)

    Harris, Charles A.

    Due to the destructive nature of flutter, flutter testing is a mandatory requirement for certification of both civilian and military aircraft. However, along with the complexity of newer aircraft, the time and cost associated with flutter testing has increased dramatically. Considering that many of the test techniques and analysis methods used to perform flutter testing date back to the 1950s and 1960's it may be time to take a fresh look at how flutter testing can best be accomplished. This thesis revisits flutter testing techniques and proposes an alternative to traditional flutter testing. The alternative uses flight test data from an aircraft that is performing an acceleration to clear the flutter envelope of the aircraft. Four academic issues arise from this new test approach. (1) Are frequencies and dampings affected by the acceleration of the aircraft? (2) Can parameter identification algorithms extract frequency and damping values from the time varying data? (3) Can the vibration response at airspeeds (or Mach numbers) beyond which the aircraft has accelerated be anticipated? (4) What formal criteria can be used to determine when the aircraft needs to end the acceleration and terminate the test point? The academic contribution of this thesis is to address these issues. It is shown that although the frequencies and damping values do change the change is so small that it is irrelevant. It is also shown that by taking small windows of data, within which the change in parameters is small, it is possible to accurately identify parameters from the time varying data. Finally it is shown that at least in principal parameters can be predicted using data from sub-critical airspeeds, and that testing can be discontinued before an unstable flight condition is reached.

  19. A study of ion acceleration, asymmetric optical pumping and low frequency waves in two expanding helicon plasmas

    NASA Astrophysics Data System (ADS)

    Sun, Xuan

    This work concerns measurements of parallel ion flow, optical pumping, and low frequency waves in expanding plasmas generated by two different helicon plasma sources. The measurements confirm numerical predictions of the formation of a current-free double layer in a region of diverging magnetic field. With laser-induced fluorescence (LIF), the double layer structure in both helicon plasma sources was investigated through measurements of the bulk parallel ion flow speed. Both double layers have a total potential drop of 3-4 kTe and length scales smaller than ion-neutral mean-free-path. A stronger double layer, with a potential drop of ˜ 6kTe , was created in a uniform magnetic field region with a plasma limiting aperture plate. During the investigations of ion acceleration in expanding plasmas, a new phenomenon, asymmetrical optical pumping (AOP) due to the acceleration of ions in magnetic field gradient, was observed. The signature of AOP is a difference in the LIF emission amplitude from a pair of Zeeman-split ion states. A model that reproduces the dependence of the AOP on magnetic-field and ion-velocity gradients is described. With magnetic fluctuation probes, low frequency, transverse, electromagnetic waves were also identified in the expanding helicon plasma. The wave is localized to the vicinity of the maximum plasma density gradient and appears only at low neutral pressure. Based on the scaling of the wave frequency and amplitude with magnetic field strength, the wave was identified as the resistive drift Alfven wave.

  20. Disparate British Breast Reconstruction Utilization: Is Universal Coverage Sufficient to Ensure Expanded Care?

    PubMed Central

    Offodile, Anaeze C.

    2016-01-01

    Summary: Our intent is to improve the understanding of the ability of healthcare providers to deliver high-quality care as we approach an era of universal coverage. We adopted 2 unique vantage points in this article: (1) the mandated coverage for immediate breast reconstruction (IBR) surgery as a microcosmic surrogate for universal coverage overall and (2) we then scrutinized the respective IBR utilization rates in a contemporaneous system of 2 healthcare delivery models in the United Kingdom, that is, the public National Health Service trust versus private-sector hospitals. A literature review was performed for IBR rates across public trust and private-sector hospitals in the United Kingdom. The IBR rate among public trust hospitals was 17% compared with 43% in the private sector. In the trust hospital setting, the enactment of 2 government mandates, intended to increase the access to cancer care, seemed to fall short in maximizing the ability of surgical practitioners to deliver quality care to patients. Among women who did not receive IBR, 65% felt that they had received the sufficient amount of information to appropriately inform their decision. In addition, only 46% of this same cohort reported a consultation with a reconstructive surgeon preoperatively. Private-sector hospitals delivered better IBR care because of the likely presence of infrastructure and financial incentives for physicians. These results serve as a call for a better alignment between policy initiatives designed to expand care access and the perogatives of physicians to ensure an optimized delivery of the expanded care such policy mandates. PMID:27482486

  1. Disparate British Breast Reconstruction Utilization: Is Universal Coverage Sufficient to Ensure Expanded Care?

    PubMed

    Offodile, Anaeze C; Guo, Lifei

    2016-06-01

    Our intent is to improve the understanding of the ability of healthcare providers to deliver high-quality care as we approach an era of universal coverage. We adopted 2 unique vantage points in this article: (1) the mandated coverage for immediate breast reconstruction (IBR) surgery as a microcosmic surrogate for universal coverage overall and (2) we then scrutinized the respective IBR utilization rates in a contemporaneous system of 2 healthcare delivery models in the United Kingdom, that is, the public National Health Service trust versus private-sector hospitals. A literature review was performed for IBR rates across public trust and private-sector hospitals in the United Kingdom. The IBR rate among public trust hospitals was 17% compared with 43% in the private sector. In the trust hospital setting, the enactment of 2 government mandates, intended to increase the access to cancer care, seemed to fall short in maximizing the ability of surgical practitioners to deliver quality care to patients. Among women who did not receive IBR, 65% felt that they had received the sufficient amount of information to appropriately inform their decision. In addition, only 46% of this same cohort reported a consultation with a reconstructive surgeon preoperatively. Private-sector hospitals delivered better IBR care because of the likely presence of infrastructure and financial incentives for physicians. These results serve as a call for a better alignment between policy initiatives designed to expand care access and the perogatives of physicians to ensure an optimized delivery of the expanded care such policy mandates. PMID:27482486

  2. Exploring a matter-dominated model with bulk viscosity to drive the accelerated expansion of the Universe

    SciTech Connect

    Avelino, Arturo; Nucamendi, Ulises E-mail: ulises@ifm.umich.mx

    2010-08-01

    We explore the viability of a bulk viscous matter-dominated Universe to explain the present accelerated expansion of the Universe. The model is composed by a pressureless fluid with bulk viscosity of the form ζ = ζ{sub 0}+ζ{sub 1}H where ζ{sub 0} and ζ{sub 1} are constants and H is the Hubble parameter. The pressureless fluid characterizes both the baryon and dark matter components. We study the behavior of the Universe according to this model analyzing the scale factor as well as some curvature scalars and the matter density. On the other hand, we compute the best estimated values of ζ{sub 0} and ζ{sub 1} using the type Ia Supernovae (SNe Ia) probe. We find that from all the possible scenarios for the Universe, the preferred one by the best estimated values of (ζ{sub 0},ζ{sub 1}) is that of an expanding Universe beginning with a Big-Bang, followed by a decelerated expansion at early times, and with a smooth transition in recent times to an accelerated expansion epoch that is going to continue forever. The predicted age of the Universe is a little smaller than the mean value of the observational constraint coming from the oldest globular clusters but it is still inside of the confidence interval of this constraint. A drawback of the model is the violation of the local second law of thermodynamics in redshifts z∼>1. However, when we assume ζ{sub 1} = 0, the simple model ζ = ζ{sub 0} evaluated at the best estimated value for ζ{sub 0} satisfies the local second law of thermodynamics, the age of the Universe is in perfect agreement with the constraint of globular clusters, and it also has a Big-Bang, followed by a decelerated expansion with the smooth transition to an accelerated expansion epoch in late times, that is going to continue forever.

  3. Exploring a matter-dominated model with bulk viscosity to drive the accelerated expansion of the Universe

    NASA Astrophysics Data System (ADS)

    Avelino, Arturo; Nucamendi, Ulises

    2010-08-01

    We explore the viability of a bulk viscous matter-dominated Universe to explain the present accelerated expansion of the Universe. The model is composed by a pressureless fluid with bulk viscosity of the form ζ = ζ0+ζ1H where ζ0 and ζ1 are constants and H is the Hubble parameter. The pressureless fluid characterizes both the baryon and dark matter components. We study the behavior of the Universe according to this model analyzing the scale factor as well as some curvature scalars and the matter density. On the other hand, we compute the best estimated values of ζ0 and ζ1 using the type Ia Supernovae (SNe Ia) probe. We find that from all the possible scenarios for the Universe, the preferred one by the best estimated values of (ζ0,ζ1) is that of an expanding Universe beginning with a Big-Bang, followed by a decelerated expansion at early times, and with a smooth transition in recent times to an accelerated expansion epoch that is going to continue forever. The predicted age of the Universe is a little smaller than the mean value of the observational constraint coming from the oldest globular clusters but it is still inside of the confidence interval of this constraint. A drawback of the model is the violation of the local second law of thermodynamics in redshifts zgtrsim1. However, when we assume ζ1 = 0, the simple model ζ = ζ0 evaluated at the best estimated value for ζ0 satisfies the local second law of thermodynamics, the age of the Universe is in perfect agreement with the constraint of globular clusters, and it also has a Big-Bang, followed by a decelerated expansion with the smooth transition to an accelerated expansion epoch in late times, that is going to continue forever.

  4. Some clues to understand MOND and the accelerated expansion of the universe

    NASA Astrophysics Data System (ADS)

    Tank, Hasmukh K.

    2011-12-01

    This letter points out that the values of `critical-acceleration' of MOND, and the `accelerated-expansion' of the universe are just two of the fourteen strikingly equal values of accelerations recurring in different physical situations. Some of them could be explained by a new law of equality of potential-energy and energy-of-mass of reasonably-independent systems (Tank in Astrophys. Space Sci. 330:203-205, 2010; Tank in Adv. Stud. Theor. Phys. 5:45-55, 2011). This new conservation-law, of equality of potential-energy, energy-of-mass and `kinetic-energy' may be a clue to understand MOND, and the `accelerated-expansion' of the universe. Alternative expressions for the cosmological red-shift, the `critical-acceleration' of MOND and Newton's law of universal gravitation are also presented for comparison of three different accelerations.

  5. SELF-SIMILAR DYNAMICAL RELAXATION OF DARK MATTER HALOS IN AN EXPANDING UNIVERSE

    SciTech Connect

    Lapi, A.; Cavaliere, A.

    2011-12-20

    We investigate the structure of cold dark matter halos using advanced models of spherical collapse and accretion in an expanding universe. These are based on solving time-dependent equations for the moments of the phase-space distribution function in the fluid approximation; our approach includes non-radial random motions and, most importantly, an advanced treatment of both dynamical relaxation effects that take place in the infalling matter: phase-mixing associated with shell crossing and collective collisions related to physical clumpiness. We find self-similar solutions for the spherically averaged profiles of mass density {rho}(r), pseudo phase-space density Q(r), and anisotropy parameter {beta}(r). These profiles agree with the outcomes of state-of-the-art N-body simulations in the radial range currently probed by the latter; at smaller radii, we provide specific predictions. In the perspective provided by our self-similar solutions, we link the halo structure to its two-stage growth history and propose the following picture. During the early fast collapse of the inner region dominated by a few merging clumps, efficient dynamical relaxation plays a key role in producing closely universal mass density and pseudo phase-space density profiles; in particular, these are found to depend only weakly on the detailed shape of the initial perturbation and the related collapse times. The subsequent inside-out growth of the outer regions feeds on the slow accretion of many small clumps and diffuse matter; thus the outskirts are only mildly affected by dynamical relaxation but are more sensitive to asymmetries and cosmological variance.

  6. A New Viewpoint (The expanding universe, Dark energy and Dark matter)

    NASA Astrophysics Data System (ADS)

    Cwele, Daniel

    2011-10-01

    Just as the relativity paradox once threatened the validity of physics in Albert Einstein's days, the cosmos paradox, the galaxy rotation paradox and the experimental invalidity of the theory of dark matter and dark energy threaten the stability and validity of physics today. These theories and ideas and many others, including the Big Bang theory, all depend almost entirely on the notion of the expanding universe, Edwin Hubble's observations and reports and the observational inconsistencies of modern day theoretical Physics and Astrophysics on related subjects. However, much of the evidence collected in experimental Physics and Astronomy aimed at proving many of these ideas and theories is ambiguous, and can be used to prove other theories, given a different interpretation of its implications. The argument offered here is aimed at providing one such interpretation, attacking the present day theories of dark energy, dark matter and the Big Bang, and proposing a new Cosmological theory based on a modification of Isaac Newton's laws and an expansion on Albert Einstein's theories, without assuming any invalidity or questionability on present day cosmological data and astronomical observations.

  7. Collision of strong gravitational and electromagnetic waves in the expanding universe

    NASA Astrophysics Data System (ADS)

    Alekseev, G. A.

    2016-03-01

    An exact analytical model of the process of collision and nonlinear interaction of gravitational and/or electromagnetic soliton waves and strong nonsoliton electromagnetic traveling waves of arbitrary profile propagating in the expanding universe (the symmetric Kasner spacetime) is presented. In contrast to intuitive expectations that rather strong traveling waves can destroy the soliton, it occurs that the soliton survives during its interaction with electromagnetic waves of arbitrary amplitude and profile, but its parameters begin to evolve under the influence of this interaction. If a traveling electromagnetic wave possesses a finite duration, the soliton parameters after interaction take constant values again, but these values in general are different from those before the interaction. Based on exact solutions of the Einstein-Maxwell equations, our model demonstrates a series of nonlinear phenomena, such as (a) creation of gravitational waves in the collision of two electromagnetic waves, (b) creation of electromagnetic soliton waves in the collision of a gravitational soliton with traveling electromagnetic waves, (c) scattering of a part of a soliton wave in the direction of propagation of a traveling electromagnetic wave, and (d) quasiperiodic oscillating character of fields in the wave interaction region and multiple mutual transformations of gravitational and electromagnetic waves in this region. The figures illustrate these features of nonlinear wave interactions in general relativity.

  8. Expanding the Enzyme Universe: Accessing Non-Natural Reactions by Mechanism-Guided Directed Evolution

    PubMed Central

    Renata, Hans; Wang, Z. Jane

    2015-01-01

    High selectivities and exquisite control over reaction outcomes entice chemists to use biocatalysts in organic synthesis. However, many useful reactions are not accessible because they are not in nature’s known repertoire. We will use this review to outline an evolutionary approach to engineering enzymes to catalyze reactions not found in nature. We begin with examples of how nature has discovered new catalytic functions and how such evolutionary progressions have been recapitulated in the laboratory starting from extant enzymes. We then examine non-native enzyme activities that have been discovered and exploited for chemical synthesis, emphasizing reactions that do not have natural counterparts. The new functions have mechanistic parallels to the native reaction mechanisms that often manifest as catalytic promiscuity and the ability to convert from one function to the other with minimal mutation. We present examples of how non-natural activities have been improved by directed evolution, mimicking the process used by nature to create new catalysts. Examples of new enzyme functions include epoxide opening reactions with non-natural nucleophiles catalyzed by a laboratory-evolved halohydrin dehalogenase, cyclopropanation and other carbene transfer reactions catalyzed by cytochrome P450 variants, and non-natural modes of cyclization by a modified terpene synthase. Lastly, we describe discoveries of non-native catalytic functions that may provide future opportunities for expanding the enzyme universe. PMID:25649694

  9. Experimental Demonstration of Collisionless Particle Acceleration Mechanisms and Entrainment of Ambient Plasma Ions by a Rapidly Expanding Diamagnetic Cavity.

    NASA Astrophysics Data System (ADS)

    Bonde, J.; Vincena, S. T.; Gekelman, W. N.

    2015-12-01

    The collisionless coupling of an expanding diamagnetic cavity to a magnetized, ambient plasma is studied in a laboratory environment using a laser-produced plasma (LPP). The seed LPP rapidly expands with velocities up to the background Alfvén speed, vexp ≤ vA. The boundary layer of the expansion is characterized with in situ diagnostics as a cylindrical version of the Ferraro-Rosenbluth current sheath. Maintenance of quasi-neutrality in this sheath forms an electric field opposing the cross-field expansion which simultaneously drives the electron current that forms the diamagnetic cavity, decelerates the LPP ions to stagnation, and accelerates ambient ions inward. The field topology across the background magnetic field is identical to that described by Bernhardt, et al. [1] for the AMPTE magnetotail barium releases. The boundary along the magnetic field, however, is shown to contain an electric field with E·B ≠ 0, which is absent in simple fluid models of diamagnetic cavities. The electric fields at this boundary help explain previous observations in the experiment of the ejection of suprathermal electrons and return currents that generated whistler- and Alfvén-wave radiation in the ambient plasma. Magnetic loops and an emissive probe measure the magnetic field and electrostatic potential along 3 dimensions while a laser-induced fluorescence scheme measures the cross-field flow of the ambient argon ions as they penetrate the diamagnetic cavity. Particle orbit solvers employing the measured fields corroborate the flow diagnostic and predict strong outflows of ambient ions with higher charge to mass ratios after diamagnetic cavity collapse. This experiment was conducted in the Large Plasma Device at the Basic Plasma Science Facility and funded by grants from the US Department of Energy and the National Science Foundation. [1] P.A. Bernhardt, R.A. Roussel-Dupre, M.B. Pongratz, J. Geophys. Res. 92, 57777 (1987).

  10. Growth of perturbations in an expanding universe with Bose-Einstein condensate dark matter

    NASA Astrophysics Data System (ADS)

    Chavanis, P. H.

    2012-01-01

    We study the growth of perturbations in an expanding Newtonian universe with Bose-Einstein condensate (BEC) dark matter. We first ignore special relativistic effects and derive a differential equation that governs the evolution of the density contrast in the linear regime. This equation, which takes quantum pressure and self-interaction into account, can be solved analytically in several cases. We argue that an attractive self-interaction can enhance the Jeans instability and fasten the formation of structures. Then, we take pressure effects (coming from special relativity) into account in the evolution of the cosmic fluid and add the contribution of radiation, baryons, and dark energy (cosmological constant). For BEC dark matter with repulsive self-interaction (positive pressure) the scale factor increases more rapidly than in the standard ΛCDM model where dark matter is pressureless, while it increases less rapidly for BEC dark matter with attractive self-interaction (negative pressure). We study the linear development of the perturbations in these two cases and show that the perturbations grow faster in BEC dark matter than in pressureless dark matter. Finally, we consider a "dark fluid" with a generalized equation of state p = (αρ + kρ2)c2 having a component p = kρ2c2 similar to BEC dark matter and a component p = αρc2 mimicking the effect of the cosmological constant (dark energy). We find optimal parameters that give good agreement with the standard ΛCDM model that assumes a finite cosmological constant.

  11. Development of the Accelerator Mass Spectrometry technology at the Comenius University in Bratislava

    NASA Astrophysics Data System (ADS)

    Povinec, Pavel P.; Masarik, Jozef; Ješkovský, Miroslav; Kaizer, Jakub; Šivo, Alexander; Breier, Robert; Pánik, Ján; Staníček, Jaroslav; Richtáriková, Marta; Zahoran, Miroslav; Zeman, Jakub

    2015-10-01

    An Accelerator Mass Spectrometry (AMS) laboratory has been established at the Centre for Nuclear and Accelerator Technologies (CENTA) at the Comenius University in Bratislava comprising of a MC-SNICS ion source, 3 MV Pelletron tandem accelerator, and an analyzer of accelerated ions. The preparation of targets for 14C and 129I AMS measurements is described in detail. The development of AMS techniques for potassium, uranium and thorium analysis in radiopure materials required for ultra-low background underground experiments is briefly mentioned.

  12. Einstein's other gravity and the acceleration of the Universe

    SciTech Connect

    Linder, Eric V.

    2010-06-15

    Spacetime curvature plays the primary role in general relativity but Einstein later considered a theory where torsion was the central quantity. Just as the Einstein-Hilbert action in the Ricci curvature scalar R can be generalized to f(R) gravity, we consider extensions of teleparallel, or torsion scalar T, gravity to f(T) theories. The field equations are naturally second order, avoiding pathologies, and can give rise to cosmic acceleration with unique features.

  13. A universal postprocessing toolkit for accelerator simulation and data analysis.

    SciTech Connect

    Borland, M.

    1998-12-16

    The Self-Describing Data Sets (SDDS) toolkit comprises about 70 generally-applicable programs sharing a common data protocol. At the Advanced Photon Source (APS), SDDS performs the vast majority of operational data collection and processing, most data display functions, and many control functions. In addition, a number of accelerator simulation codes use SDDS for all post-processing and data display. This has three principle advantages: first, simulation codes need not provide customized post-processing tools, thus simplifying development and maintenance. Second, users can enhance code capabilities without changing the code itself, by adding SDDS-based pre- and post-processing. Third, multiple codes can be used together more easily, by employing SDDS for data transfer and adaptation. Given its broad applicability, the SDDS file protocol is surprisingly simple, making it quite easy for simulations to generate SDDS-compliant data. This paper discusses the philosophy behind SDDS, contrasting it with some recent trends, and outlines the capabilities of the toolkit. The paper also gives examples of using SDDS for accelerator simulation.

  14. Laser wakefield acceleration experiments at the University of Michigan

    SciTech Connect

    Matsuoka, T.; McGuffey, C.; Horovitz, Y.; Dollar, F.; Bulanov, S. S.; Chvykov, V.; Kalintchenko, G.; Reed, S.; Rousseau, P.; Yanovsky, V.; Maksimchuk, A.; Krushelnick, K.; Huntington, C. M.; Drake, R. P.; Levin, M.; Zigler, A.

    2009-01-22

    Laser wakefield acceleration (LWFA) in a supersonic gas-jet using a self-guided laser pulse was studied by changing the laser power and electron density. The recently upgraded HERCULES laser facility equipped with wavefront correction enables a peak intensity of 8x10{sup 19} W/cm{sup 2} at laser power of 100 TW to be delivered to the gas-jet using f/10 focusing optics. We found that electron beam charge was increased significantly with an increase of the laser power from 30 TW to 80 TW and showed density threshold behavior at a fixed laser power. Betatron motion of electrons was also observed depending on laser power and electron density.

  15. Accelerating Universe from Gravitational Leakage into Extra Dimensions: Testing with Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Zhu, Zong-Hong; Alcaniz, Jailson S.

    2005-02-01

    There is mounting observational evidence that the expansion of our universe is undergoing an acceleration. A dark energy component has usually been invoked as the most feasible mechanism for the acceleration. However, it is desirable to explore alternative possibilities motivated by particle physics before adopting such an untested entity. In this work, we focus our attention on an acceleration mechanism arising from gravitational leakage into extra dimensions. We test this scenario with high-z Type Ia supernovae compiled by Tonry and coworkers and recent measurements of the X-ray gas mass fractions in clusters of galaxies published by Allen and coworkers. A combination of the two databases gives, at a 99% confidence level, Ωm=0.29+0.04-0.02, Ωrc=0.21+/-0.08, and Ωk=-0.36+0.31-0.35, indicating a closed universe. We then constrain the model using the test of the turnaround redshift, zq=0, at which the universe switches from deceleration to acceleration. We show that, in order to explain that acceleration happened earlier than zq=0=0.6 within the framework of gravitational leakage into extra dimensions, a low matter density, Ωm<0.27, or a closed universe is necessary.

  16. Cosmic microwave background anisotropy from nonlinear structures in accelerating universes

    SciTech Connect

    Sakai, Nobuyuki; Inoue, Kaiki Taro

    2008-09-15

    We study the cosmic microwave background (CMB) anisotropy due to spherically symmetric nonlinear structures in flat universes with dust and a cosmological constant. By modeling a time-evolving spherical compensated void/lump by Lemaitre-Tolman-Bondi spacetimes, we numerically solve the null geodesic equations with the Einstein equations. We find that a nonlinear void redshifts the CMB photons that pass through it regardless of the distance to it. In contrast, a nonlinear lump blueshifts (or redshifts) the CMB photons if it is located near (or sufficiently far from) us. The present analysis comprehensively covers previous works based on a thin-shell approximation and a linear/second-order perturbation method and the effects of shell thickness and full nonlinearity. Our results indicate that, if quasilinear and large (> or approx.100 Mpc) voids/lumps would exist, they could be observed as cold or hot spots with temperature variance > or approx. 10{sup -5} K in the CMB sky.

  17. Median Statistics, H0, and the Accelerating Universe

    NASA Astrophysics Data System (ADS)

    Gott, J. Richard, III; Vogeley, Michael S.; Podariu, Silviu; Ratra, Bharat

    2001-03-01

    We develop median statistics that provide powerful alternatives to χ2 likelihood methods and require fewer assumptions about the data. Application to astronomical data demonstrates that median statistics lead to results that are quite similar and almost as constraining as χ2 likelihood methods but with somewhat more confidence since they do not assume Gaussianity of the errors or that their magnitudes are known. Applying median statistics to Huchra's compilation of nearly all estimates of the Hubble constant, we find a median value H0=67 km s-1 Mpc-1. Median statistics assume only that the measurements are independent and free of systematic errors. This estimate is arguably the best summary of current knowledge because it uses all available data and, unlike other estimates, makes no assumption about the distribution of measurement errors. The 95% range of purely statistical errors is +/-2 km s-1 Mpc-1. The high degree of statistical accuracy of this result demonstrates the power of using only these two assumptions and leads us to analyze the range of possible systematic errors in the median, which we estimate to be roughly +/-5 km s-1 Mpc-1 (95% limits), dominating over the statistical errors. Using a Bayesian median statistics treatment of high-redshift Type Ia supernovae (SNe Ia) apparent magnitude versus redshift data from Riess et al., we find the posterior probability that the cosmological constant Λ>0 is 70% or 89%, depending on the prior information we include. We find the posterior probability of an open universe is about 47%, and the probability of a spatially flat universe is 51% or 38%. Our results generally support the observers' conclusions but indicate weaker evidence for Λ>0 (less than 2 σ). Median statistics analysis of the Perlmutter et al. high-redshift SNe Ia data shows that the best-fit flat-Λ model is favored over the best-fit Λ=0 open model by odds of 366:1 the corresponding Riess et al. odds are 3:1 (assuming in each case prior odds of

  18. A New Landscape: Opportunities and Pitfalls for Universities Expanding in the Persian Gulf

    ERIC Educational Resources Information Center

    DiConsiglio, John

    2009-01-01

    Dozens of universities--primarily from the United States, United Kingdom, and Australia--are eyeing the Gulf region as a largely untapped reservoir of academic potential and economic opportunity. During the last few years, UAE states like Dubai, Abu Dhabi, Qatar, and Ras al Khaymah have spent billions to entice top universities. And many colleges…

  19. Some Cosmological Models for Poincare Gauge Gravity and Accelerated Expansion of the Universe

    SciTech Connect

    Mebarki, N.

    2010-10-31

    Two cosmological Models for the Poincare Gauge Gravity theory with a non vanishing torsion are proposed. It is shown that the torsion plays an important role in explaining the accelerated expansion of the universe. Some of the cosmological parameters are also expressed in terms of the redshift and the dark energy scenarios are discussed.

  20. Revised fits to Δα/α in consistency with the accelerating universe

    NASA Astrophysics Data System (ADS)

    Fujii, Yasunori

    2009-01-01

    An attempt is made for a new type of analysis of the time-variability of the fine-structure constant trying to fit the most recent result from the laboratory measurements, the Oklo constraint and the data from the QSO absorption lines all in consistency with the accelerating universe.

  1. Late time acceleration of the 3-space in a higher dimensional steady state universe in dilaton gravity

    SciTech Connect

    Akarsu, Özgür; Dereli, Tekin E-mail: tdereli@ku.edu.tr

    2013-02-01

    We present cosmological solutions for (1+3+n)-dimensional steady state universe in dilaton gravity with an arbitrary dilaton coupling constant w and exponential dilaton self-interaction potentials in the string frame. We focus particularly on the class in which the 3-space expands with a time varying deceleration parameter. We discuss the number of the internal dimensions and the value of the dilaton coupling constant to determine the cases that are consistent with the observed universe and the primordial nucleosynthesis. The 3-space starts with a decelerated expansion rate and evolves into accelerated expansion phase subject to the values of w and n, but ends with a Big Rip in all cases. We discuss the cosmological evolution in further detail for the cases w = 1 and w = ½ that permit exact solutions. We also comment on how the universe would be conceived by an observer in four dimensions who is unaware of the internal dimensions and thinks that the conventional general relativity is valid at cosmological scales.

  2. Roles of Different Forms of Scale Factor in Non-linear Electrodynamics for Accelerating Universe

    NASA Astrophysics Data System (ADS)

    Maity, Sayani; Debnath, Ujjal

    2013-07-01

    In this work, we have assumed the modified Lagrangian of non-linear electrodynamics for accelerated universe. The energy density and pressure for non-linear electromagnetic theory have been considered in terms of both electric and magnetic fields. The Einstein's filed equations have been considered in FRW universe for Hořava-Lifshitz gravity. Since we are considering the non-linear form of Lagrangian for accelerating universe, so four forms of scale factors like logamediate, intermediate, emergent and power law forms are chosen in our investigation. For every expansion, the natures of electric field and magnetic field have been shown through graphical representation. The electric and magnetic fields increase for logamediate, intermediate and emergent expansion and decrease in power law expansion.

  3. Supernovae, Dark Energy and the Accelerating Universe: How DOE Helped to Win (yet another) Nobel Prize

    ScienceCinema

    Perlmutter, Saul

    2016-07-12

    The Department of Energy (DOE) hosted an event Friday, January 13, with 2011 Physics Nobel Laureate Saul Perlmutter. Dr. Perlmutter, a physicist at the Department’s Lawrence Berkeley National Laboratory and a professor of physics at the University of California at Berkeley, won the 2011 Nobel Prize in Physics “for the discovery of the accelerating expansion of the Universe through observations of distant supernovae.” DOE’s Office of Science has supported Dr. Perlmutter’s research at Berkeley Lab since 1983. After the introduction from Secretary of Energy Steven Chu, Dr. Perlmutter delivered a presentation entitled "Supernovae, Dark Energy and the Accelerating Universe: How DOE Helped to Win (yet another) Nobel Prize." [Copied with editing from DOE Media Advisory issued January 10th, found at http://energy.gov/articles/energy-department-host-event-2011-physics-nobel-laureate-saul-perlmutter

  4. Supernovae, Dark Energy and the Accelerating Universe: How DOE Helped to Win (yet another) Nobel Prize

    SciTech Connect

    Perlmutter, Saul

    2012-01-13

    The Department of Energy (DOE) hosted an event Friday, January 13, with 2011 Physics Nobel Laureate Saul Perlmutter. Dr. Perlmutter, a physicist at the Department’s Lawrence Berkeley National Laboratory and a professor of physics at the University of California at Berkeley, won the 2011 Nobel Prize in Physics “for the discovery of the accelerating expansion of the Universe through observations of distant supernovae.” DOE’s Office of Science has supported Dr. Perlmutter’s research at Berkeley Lab since 1983. After the introduction from Secretary of Energy Steven Chu, Dr. Perlmutter delivered a presentation entitled "Supernovae, Dark Energy and the Accelerating Universe: How DOE Helped to Win (yet another) Nobel Prize." [Copied with editing from DOE Media Advisory issued January 10th, found at http://energy.gov/articles/energy-department-host-event-2011-physics-nobel-laureate-saul-perlmutter

  5. Expanding the universe of categorical syllogisms: a challenge for reasoning researchers.

    PubMed

    Roberts, Maxwell J

    2005-11-01

    Syllogistic reasoning, in which people identify conclusions from quantified premise pairs, remains a benchmark task whose patterns of data must be accounted for by general theories of deductive reasoning. However, psychologists have confined themselves to administering only the 64 premise pairs historically identified by Aristotle. By utilizing all combinations of negations, the present article identifies an expanded set of 576 premise pairs and gives the valid conclusions that they support. Many of these have interesting properties, and the identification of predictions and their verification will be an important next step for all proponents of such theories.

  6. Searching for Baryon Acoustic Oscillations in Intergalactic Absorption: The Expanding Universe

    SciTech Connect

    2010-01-01

    Credits: Science: Michael L. Norman, Robert Harkness, Pascal Paschos, Rick Wagner, San Diego Supercomputer Center/University of California, San Diego Visualization: Mark Hereld, Joseph A. Insley, Michael E. Papka, Argonne National Laboratory; Eric C. Olson, University of Chicago This research used resources of the Argonne Leadership Computing Facility at Argonne National Laboratory, which is supported by the Office of Science of the U.S. Dept. of Energy under contract DE-AC02-06CH11357. The computation was performed at the National Institute for Computational Sciences (NICS).

  7. Expanding Downward: Innovation, Diffusion, and State Policy Adoptions of Universal Preschool

    ERIC Educational Resources Information Center

    Curran, F. Chris

    2015-01-01

    Framed within the theoretical framework of policy innovation and diffusion, this study explores both interstate (diffusion) and intrastate predictors of adoption of state universal preschool policies. Event history analysis methodology is applied to a state level dataset drawn from the Census, the NCES Common Core, the Book of the States, and…

  8. The Internal Audit Function: Playing an Expanded Role in College and University Management.

    ERIC Educational Resources Information Center

    Johnson, Sandra

    1992-01-01

    A survey of 90 colleges and universities found that 40 percent have internal audit departments. Information on auditor time allocation, salary ranges, departmental independence, and auditor roles and responsibilities was collected. A summary analysis by type of institution (large, small, research, nonresearch, public, independent, four-year,…

  9. Expanding Horizons for Students with Dyslexia in the 21st Century: Universal Design and Mobile Technology

    ERIC Educational Resources Information Center

    Reid, Gavin; Strnadova, Iva; Cumming, Therese

    2013-01-01

    This paper discusses the role of mobile technology in supporting people with dyslexia within the theoretical framework of Universal Design for Learning. The authors discuss how students with dyslexia can use mobile technology to address a diverse range of academic needs (such as reading, composing text, notetaking, metacognition and studying…

  10. The Expanding Universe: Time, Space and Spirit--Keys to Scientific Literacy Series.

    ERIC Educational Resources Information Center

    Stonebarger, Bill

    Nearly every culture has made important discoveries about the universe. Most cultures have searched for a better understanding of the cosmos and how the earth and human life relate. The discussion in this booklet considers time, space, and spirit. Time refers to a sense of history; space refers to geography; and spirit refers to life and thought.…

  11. The Unfolding Trends and Consequences of Expanding Higher Education in Ethiopia: Massive Universities, Massive Challenges

    ERIC Educational Resources Information Center

    Tessema, Kedir Assefa

    2009-01-01

    There have been significant increases in the number of universities and student enrollments in the last fifteen years in Ethiopia. The numerical gains have brought about improved access to higher education for students. The expansion has also diversified fields of study and opened opportunities to pursue higher degrees to a significant number of…

  12. Expanding clinical medical training opportunities at the University of Nairobi: adapting a regional medical education model from the WWAMI program at the University of Washington.

    PubMed

    Child, Mara J; Kiarie, James N; Allen, Suzanne M; Nduati, Ruth; Wasserheit, Judith N; Kibore, Minnie W; John-Stewart, Grace; Njiri, Francis J; O'Malley, Gabrielle; Kinuthia, Raphael; Norris, Tom E; Farquhar, Carey

    2014-08-01

    A major medical education need in Sub-Saharan Africa includes expanding clinical training opportunities to develop health professionals. Medical education expansion is a complicated process that requires significant investment of financial and human resources, but it can also provide opportunities for innovative approaches and partnerships. In 2010, the U.S. President's Emergency Plan for AIDS Relief launched the Medical Education Partnership Initiative to invest in medical education and health system strengthening in Africa. Building on a 30-year collaborative clinical and research training partnership, the University of Nairobi in Kenya developed a pilot regional medical education program modeled on the WWAMI (Washington, Wyoming, Alaska, Montana, and Idaho) medical education program at the University of Washington in the United States. The University of Nairobi adapted key elements of the WWAMI model to expand clinical training opportunities without requiring major capital construction of new buildings or campuses. The pilot program provides short-term clinical training opportunities for undergraduate students and recruits and trains clinical faculty at 14 decentralized training sites. The adaptation of a model from the Northwestern United States to address medical education needs in Kenya is a successful transfer of knowledge and practices that can be scaled up and replicated across Sub-Saharan Africa.

  13. Expanding clinical medical training opportunities at the University of Nairobi: adapting a regional medical education model from the WWAMI program at the University of Washington.

    PubMed

    Child, Mara J; Kiarie, James N; Allen, Suzanne M; Nduati, Ruth; Wasserheit, Judith N; Kibore, Minnie W; John-Stewart, Grace; Njiri, Francis J; O'Malley, Gabrielle; Kinuthia, Raphael; Norris, Tom E; Farquhar, Carey

    2014-08-01

    A major medical education need in Sub-Saharan Africa includes expanding clinical training opportunities to develop health professionals. Medical education expansion is a complicated process that requires significant investment of financial and human resources, but it can also provide opportunities for innovative approaches and partnerships. In 2010, the U.S. President's Emergency Plan for AIDS Relief launched the Medical Education Partnership Initiative to invest in medical education and health system strengthening in Africa. Building on a 30-year collaborative clinical and research training partnership, the University of Nairobi in Kenya developed a pilot regional medical education program modeled on the WWAMI (Washington, Wyoming, Alaska, Montana, and Idaho) medical education program at the University of Washington in the United States. The University of Nairobi adapted key elements of the WWAMI model to expand clinical training opportunities without requiring major capital construction of new buildings or campuses. The pilot program provides short-term clinical training opportunities for undergraduate students and recruits and trains clinical faculty at 14 decentralized training sites. The adaptation of a model from the Northwestern United States to address medical education needs in Kenya is a successful transfer of knowledge and practices that can be scaled up and replicated across Sub-Saharan Africa. PMID:25072575

  14. The Gent University 15 MeV high-current linear electron accelerator facility

    NASA Astrophysics Data System (ADS)

    Mondelaers, W.; Van Laere, K.; Goedefroot, A.; Van den Bossche, K.

    1996-01-01

    The Gent University 15 MeV 20kW linear electron accelerator facility was initially designed for fundamental nuclear physics research. During the last years a large effort has been devoted to the expansion of the range of machine applications in view of a new extensive experimental programme in the fields of atomic and solid-state physics, biomaterials research, polymer chemistry, space research, food technology, high-dose dosimetry and radiation therapy. The accelerator facility in its present configuration, the peripheral equipment and the experimental programme are described with emphasis on the original features.

  15. Contact in an expanding universe: an instructive exercise in dynamic geometry

    NASA Astrophysics Data System (ADS)

    Zimmerman, Seth

    2010-11-01

    The particular problem solved in this paper is that of calculating the time required to overtake a distant object receding under cosmic expansion, and the speed at which that object is passed. This is a rarely investigated problem leading to some interesting apparent paradoxes. We employ the problem to promote a deeper understanding of the dynamic geometry behind the expansion of space in three eras, especially for physics undergraduates. We do not utilize the standard cosmological formulae, but deliberately take a simpler approach, comprehensible to any student comfortable with differentials. This should offer an intuitive preparation for later courses in general relativity. The paper can be read straight through, or offered to a class in segments as problems to investigate. The overall intention is to leave students with a more tangible grasp of expanding space.

  16. Recent results from the University of Washington's 38 mm ram accelerator

    NASA Technical Reports Server (NTRS)

    De Turenne, J. A.; Chew, G.; Bruckner, A. P.

    1992-01-01

    The ram accelerator is a propulsive device that accelerates projectiles using gasdynamic cycles similar to those which generate thrust in airbreathing ramjets. The projectile, analogous to the centerbody of a ramjet, travels supersonically through a stationary tube containing a gaseous fuel and oxidizer mixture. The projectile itself carries no onboard propellant. A combustion zone follows the projectile and stabilizes the shock structure. The resulting pressure distribution continuously accelerates the projectile. Several modes of ram accelerator operation have been investigated experimentally and theoretically. At velocities below the Chapman-Jouguet (C-J) detonation speed of the propellant mixture, the thermally choked propulsion mode accelerates the projectiles. At projectile velocities between approximately 90 and 110 percent of the C-J speed, a transdetonative propulsion mode occurs. At velocities beyond 110 percent of the C-J speed, projectiles experience superdetonative propulsion. This paper presents recent experimental results from these propulsion modes obtained with the University of Washington's 38-mm bore ram accelerator. Data from investigations with hydrogen diluted-gas mixtures are also introduced.

  17. From HIS to IAIMS: expanding the scope of information processing applications in a German university hospital.

    PubMed Central

    Prokosch, H. U.; Puhle, B.; Müller, M.; Wagner, R.; Junghans, G.; Marquardt, K.; Dudeck, J.

    1994-01-01

    Since the mid eighties the department of medical informatics at the University Hospital of Giessen (Germany) has been engaged in the development of a comprehensive hospital information system. The installation of a campus wide network has set the basis to provide not only clinical patient-oriented information, but also general information resources for research, medical education and administrative purposes, thus creating an environment which in the U.S. became known as an integrated academic information management system (IAIMS). The underlying concept of the whole approach is to provide one-stop information shopping capabilities at the clinicians and administrators desktop in order to meet the increasing information needs of health professionals with the emerging reality of the potential benefits of computer and communication technologies. This paper describes the various steps performed to realize this concept at Giessen University Hospital and the evaluation results derived from analysis of the acceptance of these new technologies among our hospital staff. PMID:7949903

  18. Primordial inhomogeneities in the expanding universe. II - General features of spherical models at late times

    NASA Technical Reports Server (NTRS)

    Olson, D. W.; Silk, J.

    1979-01-01

    This paper studies the density profile that forms around a spherically symmetric bound central core immersed in a homogeneous-background k = 0 or k = -1 Friedmann-Robertson-Walker cosmological model, with zero pressure. Although the density profile in the linearized regime is almost arbitrary, in the nonlinear regime certain universal features of the density profile are obtained that are independent of the details of the initial conditions. The formation of 'halos' ('holes') with densities greater than (less than) the average cosmological density is discussed. It is shown that in most regions 'halos' form, and universal values are obtained for the slope of the ln (density)-ln (radius) profile in those 'halos' at late times, independently of the shape of the initial density profile. Restrictions are derived on where it is possible for 'holes' to exist at late times and on how such 'holes' must have evolved.

  19. Expanding protein universe and its origin from the biological Big Bang.

    PubMed

    Dokholyan, Nikolay V; Shakhnovich, Boris; Shakhnovich, Eugene I

    2002-10-29

    The bottom-up approach to understanding the evolution of organisms is by studying molecular evolution. With the large number of protein structures identified in the past decades, we have discovered peculiar patterns that nature imprints on protein structural space in the course of evolution. In particular, we have discovered that the universe of protein structures is organized hierarchically into a scale-free network. By understanding the cause of these patterns, we attempt to glance at the very origin of life.

  20. Dilaton-derived quintessence scenario leading naturally to the late-time acceleration of the Universe

    NASA Astrophysics Data System (ADS)

    Bean, R.; Magueijo, J.

    2001-09-01

    Quintessence scenarios provide a simple explanation for the observed acceleration of the Universe. Yet, explaining why acceleration did not start a long time ago remains a challenge. The idea that the transition from radiation to matter domination played a dynamical role in triggering acceleration has been put forward in various guises. We propose a simple dilaton-derived quintessence model in which temporary vacuum domination is naturally triggered by the radiation to matter transition. In this model Einstein's gravity is preserved but quintessence couples non-minimally to the cold dark matter, but not to ``visible'' matter. Such couplings have been attributed to the dilaton in the low-energy limit of string theory beyond tree level. We also show how a cosmological constant in the string frame translates into a quintessence-type of potential in the atomic frame.

  1. The expanding universe of ribonucleoproteins: of novel RNA-binding proteins and unconventional interactions.

    PubMed

    Beckmann, Benedikt M; Castello, Alfredo; Medenbach, Jan

    2016-06-01

    Post-transcriptional regulation of gene expression plays a critical role in almost all cellular processes. Regulation occurs mostly by RNA-binding proteins (RBPs) that recognise RNA elements and form ribonucleoproteins (RNPs) to control RNA metabolism from synthesis to decay. Recently, the repertoire of RBPs was significantly expanded owing to methodological advances such as RNA interactome capture. The newly identified RNA binders are involved in diverse biological processes and belong to a broad spectrum of protein families, many of them exhibiting enzymatic activities. This suggests the existence of an extensive crosstalk between RNA biology and other, in principle unrelated, cell functions such as intermediary metabolism. Unexpectedly, hundreds of new RBPs do not contain identifiable RNA-binding domains (RBDs), raising the question of how they interact with RNA. Despite the many functions that have been attributed to RNA, our understanding of RNPs is still mostly governed by a rather protein-centric view, leading to the idea that proteins have evolved to bind to and regulate RNA and not vice versa. However, RNPs formed by an RNA-driven interaction mechanism (RNA-determined RNPs) are abundant and offer an alternative explanation for the surprising lack of classical RBDs in many RNA-interacting proteins. Moreover, RNAs can act as scaffolds to orchestrate and organise protein networks and directly control their activity, suggesting that nucleic acids might play an important regulatory role in many cellular processes, including metabolism.

  2. The expanding universe of ribonucleoproteins: of novel RNA-binding proteins and unconventional interactions.

    PubMed

    Beckmann, Benedikt M; Castello, Alfredo; Medenbach, Jan

    2016-06-01

    Post-transcriptional regulation of gene expression plays a critical role in almost all cellular processes. Regulation occurs mostly by RNA-binding proteins (RBPs) that recognise RNA elements and form ribonucleoproteins (RNPs) to control RNA metabolism from synthesis to decay. Recently, the repertoire of RBPs was significantly expanded owing to methodological advances such as RNA interactome capture. The newly identified RNA binders are involved in diverse biological processes and belong to a broad spectrum of protein families, many of them exhibiting enzymatic activities. This suggests the existence of an extensive crosstalk between RNA biology and other, in principle unrelated, cell functions such as intermediary metabolism. Unexpectedly, hundreds of new RBPs do not contain identifiable RNA-binding domains (RBDs), raising the question of how they interact with RNA. Despite the many functions that have been attributed to RNA, our understanding of RNPs is still mostly governed by a rather protein-centric view, leading to the idea that proteins have evolved to bind to and regulate RNA and not vice versa. However, RNPs formed by an RNA-driven interaction mechanism (RNA-determined RNPs) are abundant and offer an alternative explanation for the surprising lack of classical RBDs in many RNA-interacting proteins. Moreover, RNAs can act as scaffolds to orchestrate and organise protein networks and directly control their activity, suggesting that nucleic acids might play an important regulatory role in many cellular processes, including metabolism. PMID:27165283

  3. Fermion production in dipolar electric field on de Sitter expanding universe

    SciTech Connect

    Băloi, Mihaela-Andreea Crucean, Cosmin

    2015-12-07

    The production of fermions in dipolar electric fields on de Sitter universe is studied. The amplitude and probability of pair production are computed using the exact solution of the Dirac equation in de Sitter spacetime. The form of the dipolar fields is established using the conformal invariance of the Maxwell equations. We obtain that the momentum conservation law is broken in the process of pair production in dipolar electric fields. Also we establish that there are nonvanishing probabilities for processes in which the helicity is conserved/nonconserved. The Minkowski limit is recovered when the expansion factor becomes zero.

  4. Five-dimensional metric f(R) gravity and the accelerated universe

    SciTech Connect

    Huang Biao; Li Song; Ma Yongge

    2010-03-15

    The metric f(R) theories of gravity are generalized to five-dimensional spacetimes. By assuming a hypersurface-orthogonal Killing vector field representing the compact fifth dimension, the five-dimensional theories are reduced to their four-dimensional formalism. Then we study the cosmology of a special class of f(R)={alpha}R{sup m} models in a spatially flat Friedmann-Robertson-Walker spacetime. It is shown that the parameter m can be constrained to a certain range by the current observed deceleration parameter, and its lower bound corresponds to the Kaluza-Klein theory. It turns out that both expansion and contraction of the extra dimension may prescribe the smooth transition from the deceleration era to the acceleration era in the recent past as well as an accelerated scenario for the present Universe. Hence, five-dimensional f(R) gravity can naturally account for the present accelerated expansion of the Universe. Moreover, the models predict a transition from acceleration to deceleration in the future, followed by a cosmic recollapse within finite time. This differs from the prediction of the five-dimensional Brans-Dicke theory but is inconsistent with a recent prediction based on loop quantum cosmology.

  5. To theory of asymptotically stable accelerating Universe in Riemann-Cartan spacetime

    SciTech Connect

    Garkun, A.S.; Kudin, V.I.; Minkevich, A.V. E-mail: kudzin_w@tut.by

    2014-12-01

    Homogeneous isotropic cosmological models built in the framework of the Poincar'e gauge theory of gravity based on general expression of gravitational Lagrangian with indefinite parameters are analyzed. Special points of cosmological solutions for flat cosmological models at asymptotics and conditions of their stability in dependence of indefinite parameters are found. Procedure of numerical integration of the system of gravitational equations at asymptotics is considered. Numerical solution for accelerating Universe without dark energy is obtained.

  6. Black hole in the expanding universe with arbitrary power-law expansion

    SciTech Connect

    Maeda, Kei-ichi; Nozawa, Masato

    2010-06-15

    We present a time-dependent and spatially inhomogeneous solution that interpolates the extremal Reissner-Nordstroem (RN) black hole and the Friedmann-Lemaitre-Robertson-Walker (FLRW) universe with arbitrary power-law expansion. It is an exact solution of the D-dimensional Einstein-Maxwell-dilaton system, where two Abelian gauge fields couple to the dilaton with different coupling constants, and the dilaton field has a Liouville-type exponential potential. It is shown that the system satisfies the weak energy condition. The solution involves two harmonic functions on a (D-1)-dimensional Ricci-flat base space. In the case where the harmonics have a single-point source on the Euclidean space, we find that the spacetime describes a spherically symmetric charged black hole in the FLRW universe, which is characterized by three parameters: the steepness parameter of the dilaton potential n{sub T}, the U(1) charge Q, and the nonextremality {tau}. In contrast with the extremal RN solution, the spacetime admits a nondegenerate Killing horizon unless these parameters are finely tuned. The global spacetime structures are discussed in detail.

  7. The correlation function for density perturbations in an expanding universe. I - Linear theory

    NASA Technical Reports Server (NTRS)

    Mcclelland, J.; Silk, J.

    1977-01-01

    The evolution of the two-point correlation function for adiabatic density perturbations in the early universe is studied. Analytical solutions are obtained for the evolution of linearized spherically symmetric adiabatic density perturbations and the two-point correlation function for these perturbations in the radiation-dominated portion of the early universe. The results are then extended to the regime after decoupling. It is found that: (1) adiabatic spherically symmetric perturbations comparable in scale with the maximum Jeans length would survive the radiation-dominated regime; (2) irregular fluctuations are smoothed out up to the scale of the maximum Jeans length in the radiation era, but regular fluctuations might survive on smaller scales; (3) in general, the only surviving structures for irregularly shaped adiabatic density perturbations of arbitrary but finite scale in the radiation regime are the size of or larger than the maximum Jeans length in that regime; (4) infinite plane waves with a wavelength smaller than the maximum Jeans length but larger than the critical dissipative damping scale could survive the radiation regime; and (5) black holes would also survive the radiation regime and might accrete sufficient mass after decoupling to nucleate the formation of galaxies.

  8. Accelerating universe and the time-dependent fine-structure constant

    NASA Astrophysics Data System (ADS)

    Fujii, Yasunori

    2010-11-01

    I start with assuming a gravitational scalar field as the dark-energy supposed to be responsible for the accelerating universe. Also from the point of view of unification, a scalar field implies a time-variability of certain “constants” in Nature. In this context I once derived a relation for the time-variability of the fine-structure constant α: Δα/α =ζ Ƶ(α/π) Δσ, where ζ and Ƶ are the constants of the order one, while σ on the right-hand side is the scalar field in action in the accelerating universe. I use the reduced Planckian units with c=ℏ =MP(=(8π G)-1/2)=1. I then compared the dynamics of the accelerating universe, on one hand, and Δα/α derived from the analyses of QSO absorption lines, Oklo phenomenon, also different atomic clocks in the laboratories, on the other hand. I am here going to discuss the theoretical background of the relation, based on the scalar-tensor theory invented first by Jordan in 1955.

  9. Structural genomics: keeping up with expanding knowledge of the protein universe.

    PubMed

    Grabowski, Marek; Joachimiak, Andrzej; Otwinowski, Zbyszek; Minor, Wladek

    2007-06-01

    Structural characterization of the protein universe is the main mission of Structural Genomics (SG) programs. However, progress in gene sequencing technology, set in motion in the 1990s, has resulted in rapid expansion of protein sequence space--a twelvefold increase in the past seven years. For the SG field, this creates new challenges and necessitates a re-assessment of its strategies. Nevertheless, despite the growth of sequence space, at present nearly half of the content of the Swiss-Prot database and over 40% of Pfam protein families can be structurally modeled based on structures determined so far, with SG projects making an increasingly significant contribution. The SG contribution of new Pfam structures nearly doubled from 27.2% in 2003 to 51.6% in 2006.

  10. Expanding the enzyme universe: accessing non-natural reactions by mechanism-guided directed evolution.

    PubMed

    Renata, Hans; Wang, Z Jane; Arnold, Frances H

    2015-03-01

    High selectivity and exquisite control over the outcome of reactions entice chemists to use biocatalysts in organic synthesis. However, many useful reactions are not accessible because they are not in nature's known repertoire. In this Review, we outline an evolutionary approach to engineering enzymes to catalyze reactions not found in nature. We begin with examples of how nature has discovered new catalytic functions and how such evolutionary progression has been recapitulated in the laboratory starting from extant enzymes. We then examine non-native enzyme activities that have been exploited for chemical synthesis, with an emphasis on reactions that do not have natural counterparts. Non-natural activities can be improved by directed evolution, thus mimicking the process used by nature to create new catalysts. Finally, we describe the discovery of non-native catalytic functions that may provide future opportunities for the expansion of the enzyme universe.

  11. Tidal interactions in the expanding universe - The formation of prolate systems

    NASA Technical Reports Server (NTRS)

    Binney, J.; Silk, J.

    1979-01-01

    The study estimates the magnitude of the anisotropy that can be tidally induced in neighboring initially spherical protostructures, be they protogalaxies, protoclusters, or even uncollapsed density enhancements in the large-scale structure of the universe. It is shown that the linear analysis of tidal interactions developed by Peebles (1969) predicts that the anisotropy energy of a perturbation grows to first order in a small dimensionless parameter, whereas the net angular momentum acquired is of second order. A simple model is presented for the growth of anisotropy by tidal interactions during the nonlinear stage of the development of perturbations. A possible observational test is described of the alignment predicted by the model between the orientations of large-scale perturbations and the positions of neighboring density enhancements.

  12. Organization of the 16th Advanced Accelerator Concepts (AAC) Workshop by Stanford University

    SciTech Connect

    Huang, Zhirong; Hogan, Mark

    2015-09-30

    Essentially all we know today and will learn in the future about the fundamental nature of matter is derived from probing it with directed beams of particles such as electrons, protons, neutrons, heavy ions, and photons. The resulting ability to “see” the building blocks of matter has had an immense impact on society and our standard of living. Over the last century, particle accelerators have changed the way we look at nature and the universe we live in and have become an integral part of the Nation’s technical infrastructure. Today, particle accelerators are essential tools of modern science and technology. The cost and capabilities of accelerators would be greatly enhanced by breakthroughs in acceleration methods and technology. For the last 32 years, the Advanced Accelerator Concepts (AAC) Workshop has acted as the focal point for discussion and development of the most promising acceleration physics and technology. It is a particularly effective forum where the discussion is leveraged and promoted by the unique and demanding feature of the AAC Workshop: the working group structure, in which participants are asked to consider their contributions in terms of even larger problems to be solved. The 16th Advanced Accelerator Concepts (AAC2014) Workshop was organized by Stanford University from July 13 - 18, 2014 at the Dolce Hays Mansion in San Jose, California. The conference had a record 282 attendees including 62 students. Attendees came from 11 countries representing 66 different institutions. The workshop format consisted of plenary sessions in the morning with topical leaders from around the world presenting the latest breakthroughs to the entire workshop. In the late morning and afternoons attendees broke out into eight different working groups for more detailed presentations and discussions that were summarized on the final day of the workshop. In addition, there were student tutorial presentations on two afternoons to provide in depth education and

  13. Dynamical vacuum energy in the expanding Universe confronted with observations: a dedicated study

    SciTech Connect

    Gómez-Valent, Adrià; Solà, Joan; Basilakos, Spyros E-mail: sola@ecm.ub.edu

    2015-01-01

    Despite the many efforts, our theoretical understanding of the ultimate nature of the dark energy component of the universe still lags well behind the astounding experimental evidence achieved from the increasingly sophisticated observational tools at our disposal. While the canonical possibility is a strict cosmological constant, or rigid vacuum energy density ρ{sub Λ} = const., the exceeding simplicity of this possibility lies also at the root of its unconvincing theoretical status, as there is no explanation for the existence of such constant for the entire cosmic history. Herein we explore general models of the vacuum energy density slowly evolving with the Hubble function H and/or its time derivative, ρ{sub Λ} = ρ{sub Λ}(H, H-dot ). Some of these models are actually well-motivated from the theoretical point of view and may provide a rich phenomenology that could be explored in future observations, whereas some others have more limitations. In this work, we put them to the test and elucidate which ones are still compatible with the present observations and which ones are already ruled out. We consider their implications on structure formation, in combination with data on type Ia supernovae, the Cosmic Microwave Background, the Baryonic Acoustic Oscillations, and the predicted redshift distribution of cluster-size collapsed structures. The relation of these vacuum models on possible evidence of dynamical dark energy recently pointed out in the literature is also briefly addressed.

  14. Dynamical vacuum energy in the expanding Universe confronted with observations: a dedicated study

    NASA Astrophysics Data System (ADS)

    Gómez-Valent, Adrià; Solà, Joan; Basilakos, Spyros

    2015-01-01

    Despite the many efforts, our theoretical understanding of the ultimate nature of the dark energy component of the universe still lags well behind the astounding experimental evidence achieved from the increasingly sophisticated observational tools at our disposal. While the canonical possibility is a strict cosmological constant, or rigid vacuum energy density ρΛ = const., the exceeding simplicity of this possibility lies also at the root of its unconvincing theoretical status, as there is no explanation for the existence of such constant for the entire cosmic history. Herein we explore general models of the vacuum energy density slowly evolving with the Hubble function H and/or its time derivative, ρΛ = ρΛ(H,dot H). Some of these models are actually well-motivated from the theoretical point of view and may provide a rich phenomenology that could be explored in future observations, whereas some others have more limitations. In this work, we put them to the test and elucidate which ones are still compatible with the present observations and which ones are already ruled out. We consider their implications on structure formation, in combination with data on type Ia supernovae, the Cosmic Microwave Background, the Baryonic Acoustic Oscillations, and the predicted redshift distribution of cluster-size collapsed structures. The relation of these vacuum models on possible evidence of dynamical dark energy recently pointed out in the literature is also briefly addressed.

  15. Basic science for the clinician 49: expanding the description of the RNA universe.

    PubMed

    Sigal, Leonard H

    2009-03-01

    We have come a long way in paying RNA its due respect. Originally thought to be nothing more than a shuttle of information from DNA to protein, a bearer of amino acids to the ribosome, and a splicer of messenger RNA, we now know that other RNA species are pivotal in controlling cellular functions that assure normal development and differentiation of immune cells, modulation of inflammatory mechanisms, control of proliferation of a number of hematologic lineages, and spermatogenesis (clearly, vital for the maintenance of the species!). In the future, ribozymes, antisense RNA and oligonucleotides, decoy RNA, peptide-nucleic acid chimeras, and other RNAs will probably be part of the routine armamentarium in a variety of medical practices. Targeting these to the appropriate cell may allow for highly directed therapies, maximizing efficacy and minimizing toxicity. It is a new world, an RNA world, and we will all benefit from the insights broadly outlined in this article. When I was in college and medical school, RNA was known to come in only a few varieties. There was messenger RNA, ribosomal RNA, transfer RNA, and double-stranded RNA in some viruses. And that was that! My, how times have changed!! The truth, as always, is much more complicated than we had thought. We now know that RNA is involved in splicing of mRNA and in cleaving RNA. And, recent studies have revealed even more: DNA transcription, mRNA stability, and levels of protein synthesis are all, to some degree, controlled by an entirely different set of RNAs, such as small RNAs, which come in at least 3 different broad varieties. Thus, there are now at least 10 varieties of RNAs of which I am aware at the time I write these words, and who is to say that there are not more out there? Just as the entire repertoire of the known classes of small RNAs has not yet been described, there may be different RNAs out there yet to be identified. If, in fact, the bio-universe was initially determined by RNA, not DNA, there

  16. An accelerator facility for WDM, HEDP, and HIF investigations in Nazarbayev University

    NASA Astrophysics Data System (ADS)

    Kaikanov, M.; Baigarin, K.; Tikhonov, A.; Urazbayev, A.; Kwan, J. W.; Henestroza, E.; Remnev, G.; Shubin, B.; Stepanov, A.; Shamanin, V.; Waldron, W. L.

    2016-05-01

    Nazarbayev University (NU) in Astana, Kazakhstan, is planning to build a new multi-MV, ∼10 to several hundred GW/cm2 ion accelerator facility which will be used in studies of material properties at extreme conditions relevant to ion-beam-driven inertial fusion energy, and other applications. Two design options have been considered. The first option is a 1.2 MV induction linac similar to the NDCX-II at LBNL, but with modifications, capable of heating a 1 mm spot size thin targets to a few eV temperature. The second option is a 2 - 3 MV, ∼200 kA, single-gap-diode proton accelerator powered by an inductive voltage adder. The high current proton beam can be focused to ∼1 cm spot size to obtain power densities of several hundred GW/cm2, capable of heating thick targets to temperatures of tens of eV. In both cases, a common requirement to achieving high beam intensity on target and pulse length compression is to utilize beam neutralization at the final stage of beam focusing. Initial experiments on pulsed ion beam neutralization have been carried out on a 0.3 MV, 1.5 GW single-gap ion accelerator at Tomsk Polytechnic University with the goal of creating a plasma region in front of a target at densities exceeding ∼1012 cm-3.

  17. Implications of an absolute simultaneity theory for cosmology and universe acceleration.

    PubMed

    Kipreos, Edward T

    2014-01-01

    An alternate Lorentz transformation, Absolute Lorentz Transformation (ALT), has similar kinematics to special relativity yet maintains absolute simultaneity in the context of a preferred reference frame. In this study, it is shown that ALT is compatible with current experiments to test Lorentz invariance only if the proposed preferred reference frame is locally equivalent to the Earth-centered non-rotating inertial reference frame, with the inference that in an ALT framework, preferred reference frames are associated with centers of gravitational mass. Applying this theoretical framework to cosmological data produces a scenario of universal time contraction in the past. In this scenario, past time contraction would be associated with increased levels of blueshifted light emissions from cosmological objects when viewed from our current perspective. The observation that distant Type Ia supernovae are dimmer than predicted by linear Hubble expansion currently provides the most direct evidence for an accelerating universe. Adjusting for the effects of time contraction on a redshift-distance modulus diagram produces a linear distribution of supernovae over the full redshift spectrum that is consistent with a non-accelerating universe. PMID:25536116

  18. The Accelerating Universe: Infinite Expansion, the Cosmological Constant, and the Beauty of the Cosmos

    NASA Astrophysics Data System (ADS)

    Livio, Mario

    2000-12-01

    Advance Praise for The Accelerating Universe "The Accelerating Universe is not only an informative book about modern cosmology. It is rich storytelling and, above all, a celebration of the human mind in its quest for beauty in all things." -Alan Lightman, author of Einstein's Dreams "This is a wonderfully lucid account of the extraordinary discoveries that have made the last years a golden period for observational cosmology. But Mario Livio has not only given the reader one clear explanation after another of what astronomers are up to, he has used them to construct a provocative argument for the importance of aesthetics in the development of science and for the inseparability of science, art, and culture." -Lee Smolin, author of The Life of the Cosmos "What a pleasure to read! An exciting, simple account of the universe revealed by modern astronomy. Beautifully written, clearly presented, informed by scientific and philosophical insights." -John Bahcall, Institute for Advanced Study "A book with charm, beauty, elegance, and importance. As authoritative a journey as can be taken through modern cosmology." -Allan Sandage, Observatories of the Carnegie Institution of Washington

  19. Implications of an Absolute Simultaneity Theory for Cosmology and Universe Acceleration

    PubMed Central

    Kipreos, Edward T.

    2014-01-01

    An alternate Lorentz transformation, Absolute Lorentz Transformation (ALT), has similar kinematics to special relativity yet maintains absolute simultaneity in the context of a preferred reference frame. In this study, it is shown that ALT is compatible with current experiments to test Lorentz invariance only if the proposed preferred reference frame is locally equivalent to the Earth-centered non-rotating inertial reference frame, with the inference that in an ALT framework, preferred reference frames are associated with centers of gravitational mass. Applying this theoretical framework to cosmological data produces a scenario of universal time contraction in the past. In this scenario, past time contraction would be associated with increased levels of blueshifted light emissions from cosmological objects when viewed from our current perspective. The observation that distant Type Ia supernovae are dimmer than predicted by linear Hubble expansion currently provides the most direct evidence for an accelerating universe. Adjusting for the effects of time contraction on a redshift–distance modulus diagram produces a linear distribution of supernovae over the full redshift spectrum that is consistent with a non-accelerating universe. PMID:25536116

  20. Implications of an absolute simultaneity theory for cosmology and universe acceleration.

    PubMed

    Kipreos, Edward T

    2014-01-01

    An alternate Lorentz transformation, Absolute Lorentz Transformation (ALT), has similar kinematics to special relativity yet maintains absolute simultaneity in the context of a preferred reference frame. In this study, it is shown that ALT is compatible with current experiments to test Lorentz invariance only if the proposed preferred reference frame is locally equivalent to the Earth-centered non-rotating inertial reference frame, with the inference that in an ALT framework, preferred reference frames are associated with centers of gravitational mass. Applying this theoretical framework to cosmological data produces a scenario of universal time contraction in the past. In this scenario, past time contraction would be associated with increased levels of blueshifted light emissions from cosmological objects when viewed from our current perspective. The observation that distant Type Ia supernovae are dimmer than predicted by linear Hubble expansion currently provides the most direct evidence for an accelerating universe. Adjusting for the effects of time contraction on a redshift-distance modulus diagram produces a linear distribution of supernovae over the full redshift spectrum that is consistent with a non-accelerating universe.

  1. Scalar-tensor gravity with a non-minimally coupled Higgs field and accelerating universe

    NASA Astrophysics Data System (ADS)

    Sim, Jonghyun; Lee, Tae Hoon

    2016-03-01

    We consider general couplings, including non-minimal derivative coupling, of a Higgs boson field to scalar-tensor gravity and calculate their contributions to the energy density and pressure in Friedmann-Robertson-Walker spacetime. In a special case where the kinetic term of the Higgs field is non-minimally coupled to the Einstein tensor, we seek de Sitter solutions for the cosmic scale factor and discuss the possibility that the late-time acceleration and the inflationary era of our universe can be described by means of scalar fields with self-interactions and the Yukawa potential.

  2. Metric-Field Approach to Gravitation and the Problem of the Universe Acceleration

    NASA Astrophysics Data System (ADS)

    Verozub, Leonid V.

    2002-07-01

    A metric-field approach to gravitation is presented. It is based on an idea of dependency of space-time properties on measuring instruments. Some bimetric equations that realize this idea are considered. They were tested by the binary pulsar PSR1913+16. The spherically - symmetric solution of the equations has no event horizon and no physical singularity in the center. The proper energy of a point particle is finite. There can exist supermassive compact configurations of the degenerated Fermi-gas which can be identified with observed objects in galactic centers. The problem of the Universe acceleration has a natural explanation.

  3. Cosmological implications of interacting group field theory models: Cyclic universe and accelerated expansion

    NASA Astrophysics Data System (ADS)

    de Cesare, Marco; Pithis, Andreas G. A.; Sakellariadou, Mairi

    2016-09-01

    We study the cosmological implications of interactions between spacetime quanta in the group field theory (GFT) approach to quantum gravity from a phenomenological perspective. Our work represents a first step towards understanding early Universe cosmology by studying the dynamics of the emergent continuum spacetime, as obtained from a fundamentally discrete microscopic theory. In particular, we show how GFT interactions lead to a recollapse of the Universe while preserving the bounce replacing the initial singularity, which has already been shown to occur in the free case. It is remarkable that cyclic cosmologies are thus obtained in this framework without any a priori assumption on the geometry of spatial sections of the emergent spacetime. Furthermore, we show how interactions make it possible to have an early epoch of accelerated expansion, which can be made to last for an arbitrarily large number of e -folds, without the need to introduce an ad hoc potential for the scalar field.

  4. Local transplantation of ex vivo expanded bone marrow-derived CD34-positive cells accelerates fracture healing.

    PubMed

    Kawakami, Yohei; Ii, Masaaki; Alev, Cantas; Kawamoto, Atsuhiko; Matsumoto, Tomoyuki; Kuroda, Ryosuke; Shoji, Taro; Fukui, Tomoaki; Masuda, Haruchika; Akimaru, Hiroshi; Mifune, Yutaka; Kuroda, Tomoya; Horii, Miki; Yokoyama, Ayumi; Kurosaka, Masahiro; Asahara, Takayuki

    2012-01-01

    Transplantation of bone marrow (BM) CD34(+) cells, an endothelial/hematopoietic progenitor-enriched cell population, has shown therapeutic efficiency in the treatment of ischemic diseases enhancing neovascularization. However, the number of CD34(+) cells obtained from bone marrow is not sufficient for routine clinical application. To overcome this issue, we developed a more efficient and clinically applicable CD34(+) cell expansion method. Seven-day ex vivo expansion culture of BM CD34(+) cells with a cocktail of five growth factors containing VEGF, SCF, IL-6, Flt-3 ligand, and TPO resulted in reproducible more than 20-fold increase in cell number. The favorable effect of the local transplantation of culture expanded (cEx)-BM CD34(+) cells on rat unhealing fractures was equivalent or higher than that of nonexpanded (fresh) BM CD34(+) cells exhibiting sufficient therapeutic outcome with frequent vasculogenic/osteogenic differentiation of transplanted cEx-BM CD34(+) cells and fresh BM CD34(+) cells as well as intrinsic enhancement of angiogenesis/osteogenesis at the treated fracture sites. Specifically, cEx-BM CD34(+) cell treatment demonstrated the best blood flow recovery at fracture sites compared with the nonexpanded BM CD34(+) cells. In vitro, cEx-BM CD34(+) cells showed higher colony/tube-forming capacity than nonexpanded BM CD34(+) cells. Both cells demonstrated differentiation potential into osteoblasts. Since fresh BM CD34(+) cells can be easily collected from fracture sites at the time of primary operation and stored for future use, autologous cEx-BM CD34(+) cell transplantation would be not only a simple but also a promising therapeutic strategy for unhealing fractures in the field of orthopedic trauma surgery.

  5. Expanding the ribosomal universe.

    PubMed

    Dinman, Jonathan D; Kinzy, Terri Goss

    2009-12-01

    In this issue of Structure, Taylor et al. (2009) present the most complete model of an eukaryotic ribosome to date. This achievement represents a critical milestone along the path to structurally defining the unique aspects of the eukaryotic protein synthetic machinery.

  6. The expanding polymerase universe.

    PubMed

    Goodman, M F; Tippin, B

    2000-11-01

    Over the past year, the number of known prokaryotic and eukaryotic DNA polymerases has exploded. Many of these newly discovered enzymes copy aberrant bases in the DNA template over which 'respectable' polymerases fear to tread. The next step is to unravel their functions, which are thought to range from error-prone copying of DNA lesions, somatic hypermutation and avoidance of skin cancer, to restarting stalled replication forks and repairing double-stranded DNA breaks.

  7. THE GEOMETRY EFFECTS OF AN EXPANDING UNIVERSE ON THE DETECTION OF COOL NEUTRAL GAS AT HIGH REDSHIFT

    SciTech Connect

    Curran, S. J.

    2012-03-20

    Recent high-redshift surveys for 21 cm absorption in damped Ly{alpha} absorption systems (DLAs) take the number of published searches at z{sub abs} > 2 to 25, the same number as at z{sub abs} < 2, although the detection rate at high redshift remains significantly lower (20% compared to 60%). Using the known properties of the DLAs to estimate the unknown profile widths of the 21 cm non-detections and including the limits via a survival analysis, we show that the mean spin temperature/covering factor degeneracy at high redshift is, on average, double that of the low-redshift sample. This value is significantly lower than the previous factor of eight for the spin temperatures and is about the same factor as in the angular diameter distance ratios between the low- and high-redshift samples. That is, without the need for the several pivotal assumptions, which lead to an evolution in the spin temperature, we show that the observed distribution of 21 cm detections in DLAs can be accounted for by the geometry effects of an expanding universe. That is, as yet there is no evidence of the spin temperature of gas-rich galaxies evolving with redshift.

  8. Coupled scalar fields in the late Universe: the mechanical approach and the late cosmic acceleration

    NASA Astrophysics Data System (ADS)

    Burgazli, Alvina; Zhuk, Alexander; Morais, João; Bouhmadi-López, Mariam; Sravan Kumar, K.

    2016-09-01

    In this paper, we consider the Universe at the late stage of its evolution and deep inside the cell of uniformity. At these scales, we consider the Universe to be filled with dust-like matter in the form of discretely distributed galaxies, a minimally coupled scalar field and radiation as matter sources. We investigate such a Universe in the mechanical approach. This means that the peculiar velocities of the inhomogeneities (in the form of galaxies) as well as fluctuations of other perfect fluids are non-relativistic. Such fluids are designated as coupled because they are concentrated around inhomogeneities. In the present paper we investigate the conditions under which a scalar field can become coupled, and show that, at the background level, such coupled scalar field behaves as a two component perfect fluid: a network of frustrated cosmic strings with EoS parameter w=-1/3 and a cosmological constant. The potential of this scalar field is very flat at the present time. Hence, the coupled scalar field can provide the late cosmic acceleration. The fluctuations of the energy density and pressure of this field are concentrated around the galaxies screening their gravitational potentials. Therefore, such scalar fields can be regarded as coupled to the inhomogeneities.

  9. Redshift-Drift as a Test for Discriminating Between Decelerating Inhomogeneous and Accelerating Universe Models

    NASA Astrophysics Data System (ADS)

    Mishra, Priti; Célérier, Marie-Noëlle Singh, Tejinder P.

    2015-01-01

    Exact inhomogeneous solutions of Einstein's equations have been used in the literature to build models reproducing the cosmological data without dark energy. However, owing to the degrees of freedom pertaining to these models, it is necessary to get rid of the degeneracy often exhibited by the problem of distinguishing between them and accelerating universe models. We give an overview of redshift drift in inhomogeneous cosmologies, and explain how it serves to this purpose. One class of models which fits the data is the Szekeres Swiss-cheese class where non-spherically symmetric voids exhibit a typical size of about 400 Mpc. We present our calculation of the redshift drift in this model, and compare it with the results obtained by other authors for alternate scenarios.

  10. The Accelerated Medical Program and the Liberal Arts at Boston University.

    PubMed

    Blaustein, E H; Kayne, H L

    1976-06-14

    Since September 1961, fifteen classes have matriculated in Boston University's Six- Year College of Liberal Arts--Medical Education Combined Degree Program. The applicant pool is approximately three to four times larger now than in the earlier years, with classes averaging 50 students. Academic qualifications (high-school class rank and Scholastic Aptitude Test and College Board Achievement Test results) of the entering classes have been at a consistently high level. Fifty percent or more of the graduates receive the BA degree with honors; 10% or more receive the MD degree with honors. The degree of flexibility in the liberal arts component of the program has increased and currently exceeds that of the traditional four-year premedical curriculum. These data, together with additional information concerning postgraduate professional activities, indicate that the combined accelerated program has been successful.

  11. Cosmological perturbations of self-accelerating universe in nonlinear massive gravity

    SciTech Connect

    Gümrükçüoğlu, A. Emir; Lin, Chunshan; Mukohyama, Shinji E-mail: chunshan.lin@ipmu.jp

    2012-03-01

    We study cosmological perturbations of self-accelerating universe solutions in the recently proposed nonlinear theory of massive gravity, with general matter content. While the broken diffeomorphism invariance implies that there generically are 2 tensor, 2 vector and 2 scalar degrees of freedom in the gravity sector, we find that the scalar and vector degrees have vanishing kinetic terms and nonzero mass terms. Depending on their nonlinear behavior, this indicates either nondynamical nature of these degrees or strong couplings. Assuming the former, we integrate out the 2 vector and 2 scalar degrees of freedom. We then find that in the scalar and vector sectors, gauge-invariant variables constructed from metric and matter perturbations have exactly the same quadratic action as in general relativity. The difference from general relativity arises only in the tensor sector, where the graviton mass modifies the dispersion relation of gravitational waves, with a time-dependent effective mass. This may lead to modification of stochastic gravitational wave spectrum.

  12. Performance report for the low energy compact radiocarbon accelerator mass spectrometer at Uppsala University

    NASA Astrophysics Data System (ADS)

    Salehpour, M.; Håkansson, K.; Possnert, G.; Wacker, L.; Synal, H.-A.

    2016-03-01

    A range of ion beam analysis activities are ongoing at Uppsala University, including Accelerator Mass Spectrometry (AMS). Various isotopes are used for AMS but the isotope with the widest variety of applications is radiocarbon. Up until recently, only the 5 MV Pelletron tandem accelerator had been used at our site for radiocarbon AMS, ordinarily using 12 MeV 14,13,12C3+ ions. Recently a new radiocarbon AMS system, the Green-MICADAS, developed at the ion physics group at ETH Zurich, was installed. The system has a number of outstanding features which will be described. The system operates at a terminal voltage of 175 kV and uses helium stripper gas, extracting singly charged carbon ions. The low- and high energy mass spectrometers in the system are stigmatic dipole permanent magnets (0.42 and 0.97 T) requiring no electrical power nor cooling water. The system measures both the 14C/12C and the 13C/12C ratios on-line. Performance of the system is presented for both standard mg samples as well as μg-sized samples.

  13. FRW Like Cosmological Model and Accelerated Expansion of the Universe from Non Commutative Seiberg-Witten Geometry

    SciTech Connect

    Aissaoui, H.; Bouhalouf, H.; Mebarki, N.

    2010-10-31

    An FRW like cosmological model in the non commutative Seiberg-Witten space-time is proposed. The pure NCG dynamical apparent horizon and Hawking temperature are obtained and explicit expressions of the scale factor, Hubble and deceleration parameters are derived. The accelerated expansion of the universe scenario is also discussed.

  14. Can the Virtual University Expand Access to Higher Education in Africa? The Dialectic of the Local and the Global

    ERIC Educational Resources Information Center

    Adala, A. Atieno

    2010-01-01

    A recent phenomenon in higher education is the emergence of the virtual university. Some observers have attributed its emergence to globalization and technological innovation. This dissertation study is about one particular instance of the virtual university phenomenon, the African Virtual University (AVU). The AVU initiative was launched with…

  15. J-PAS: The Javalambre-Physics of the Accelerating Universe Astrophysical Survey

    NASA Astrophysics Data System (ADS)

    Dupke, Renato a.; Benitez, Narciso; Moles, Mariano; Sodre, Laerte; J-PAS Collaboration

    2015-08-01

    The Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) is a narrow band, very wide field Cosmological Survey to be carried out from the Javalambre Astrophysical Observatory in Spain with a dedicated 2.5m telescope and a 4.7deg^2 camera with 1.2Gpix. Starting in 2016, J-PAS will observe 8600 deg^2 of the Northern Sky and measure 0.003(1+z) precision photometric redshifts for nearly 1E08 LRG and ELG galaxies plus several million QSOs, sampling an effective volume of ~14 Gpc^3 up to z = 1.3. J-PAS will also detect and measure the mass of more than a hundred thousand galaxy clusters, setting constrains on Dark Energy which rival those obtained from BAO measurements.The key to the J-PAS potential is its innovative approach the combination of 54 145°A filters, placed 100°A apart, and a multi-degree field of view (FOV) which makes it a powerful “redshift machine”, with the survey speed of a 4000 multiplexing low resolution spectrograph, but many times cheaper and much faster to build. Moreover, since the J-PAS camera is equivalent to a very large, 4.7deg^2 “IFU”, it will produce a time-resolved, 3D image of the Northern Sky with a very wide range of Astrophysical applications in Galaxy Evolution, the nearby Universe and the study of resolved stellar populations. J-PAS will have a lasting legacy value in many areas of Astrophysics, serving as a fundamental dataset for future Cosmological projects.Here, we present the overall description, status and scientific potential of the survey.

  16. J-PAS: The Javalambre-Physics of the Accelerating Universe Astrophysical Survey

    NASA Astrophysics Data System (ADS)

    Dupke, Renato A.; Benitez, Narciso; Moles, Mariano; Sodre, Laerte; Irwin, Jimmy; J-PAS Collaboration

    2016-01-01

    The Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) is a narrow band, very wide field Cosmological Survey to be carried out from the Javalambre Astrophysical Observatory in Spain with a dedicated 2.5m telescope and a 4.7deg^2 camera with 1.2Gpix. Starting in 2016, J-PAS will observe 8600 deg^2 of the Northern Sky and measure 0.003(1+z) precision photometric redshifts for nearly 1E08 LRG and ELG galaxies plus several million QSOs, sampling an effective volume of ~14 Gpc^3 up to z = 1.3. J-PAS will also detect and measure the mass of more than a hundred thousand galaxy clusters, setting constrains on Dark Energy which rival those obtained from BAO measurements.The key to the J-PAS potential is its innovative approach the combination of 54 145°A filters, placed 100°A apart, and a multi-degree field of view (FOV) which makes it a powerful "redshift machine", with the survey speed of a 4000 multiplexing low resolution spectrograph, but many times cheaper and much faster to build. Moreover, since the J-PAS camera is equivalent to a very large, 4.7deg^2 "IFU", it will produce a time-resolved, 3D image of the Northern Sky with a very wide range of Astrophysical applications in Galaxy Evolution, the nearby Universe and the study of resolved stellar populations. J-PAS will have a lasting legacy value in many areas of Astrophysics, serving as a fundamental dataset for future Cosmological projects.Here, we present the overall description, status and scientific potential of the survey.

  17. The accelerating universe and other cosmological aspects of modified gravity models

    NASA Astrophysics Data System (ADS)

    de Felice, Antonio

    I give a short introduction to standard cosmology and a review of what it is meant by "the dark energy enigma" in chapter l. In chapter 2, I mention and describe some attempts found in the literature of the past few years to attack this problem. Dark energy candidates for which the equation-of-state parameter w is less than -1 violate the dominant energy condition. In scalar-tensor theories of gravity, however, the expansion of the universe can mimic the behavior of general relativity with w < -1 dark energy, without violating any energy conditions. I examine, in chapter 3, whether this possibility is phenomenologically viable by studying Brans-Dicke models and characterizing both the naturalness of the models themselves, and additional observational constraints from limits on the time-dependence of Newton's constant. I find that only highly contrived models would lead observers to measure w < -1. In chapter 4, I consider general curvature-invariant modifications of the Einstein-Hilbert action that become important only in regions of extremely low space-time curvature. I investigate the far future evolution of the universe in such models, examining the possibilities for cosmic acceleration and other ultimate destinies. The models generically possess de Sitter space as an unstable solution and exhibit an interesting set of attractor solutions which, in some cases, provide alternatives to dark energy models. In chapter 5, I study a baryogenesis mechanism operating in the context of hyperextended inflation and making use of a coupling between the scalar field and a standard model global current, such as B or B - L . The method is efficient at temperatures at which these currents are not conserved due to some higher dimensional operator. The particle physics and cosmological phenomenology are discussed. I consider constraints stemming from nucleosynthesis and solar system experiments.

  18. Upgrading of the 4.5 MV Dynamitron accelerator at Tohoku University for microbeam and nanobeam applications

    NASA Astrophysics Data System (ADS)

    Matsuyama, S.; Ishii, K.; Fujisawa, M.; Kawamura, Y.; Tsuboi, S.; Yamanaka, K.; Watanabe, M.; Hashimoto, Y.; Ohkura, S.; Fujikawa, M.; Nagaya, T.; Komatsu, K.; Yamazaki, H.; Kikuchi, Y.

    2009-06-01

    To improve the beam brightness and the stability of the accelerator for nanobeam and microbeam applications, the Dynamitron accelerator was upgraded. Although the microbeam system at Tohoku University can focus the beam to several hundred square micrometers, its beam currents were insufficient for analyses of sub-micrometer resolution because of the lack of the accelerator brightness. For this upgrade, an ion source, with lenses in the terminal, and an acceleration tube were replaced with new ones. A control system for the ion source and lens system was also newly developed. Beam brightness of 2.6 and 0.44 pA μm -2 mrad -2 MeV -1 is currently obtained for H2+ and H1+ beams at half divergence of 0.07 mrad. The voltage stability of the accelerator was improved by adjusting the voltage stabilizing system, thereby improving the beam current stability. The Dynamitron accelerator has been operated routinely for various experiments without a serious problem.

  19. J-PAS: The Javalambre Physics of the Accelerated Universe Astrophysical Survey

    NASA Astrophysics Data System (ADS)

    Cepa, J.; Benítez, N.; Dupke, R.; Moles, M.; Sodré, L.; Cenarro, A. J.; Marín-Franch, A.; Taylor, K.; Cristóbal, D.; Fernández-Soto, A.; Mendes de Oliveira, C.; Abramo, L. R.; Alcaniz, J. S.; Overzier, R.; Hernández-Monteagudo, A.; Alfaro, E. J.; Kanaan, A.; Carvano, M.; Reis, R. R. R.; J-PAS Team

    2016-10-01

    The Javalambre Physics of the Accelerated Universe Astrophysical Survey (J-PAS) is a narrow band, very wide field Cosmological Survey to be carried out from the Javalambre Observatory in Spain with a purpose-built, dedicated 2.5 m telescope and a 4.7 sq.deg. camera with 1.2 Gpix. Starting in late 2016, J-PAS will observe 8500 sq.deg. of Northern Sky and measure Δz˜0.003(1+z) photo-z for 9× 107 LRG and ELG galaxies plus several million QSOs, sampling an effective volume of ˜ 14 Gpc3 up to z=1.3 and becoming the first radial BAO experiment to reach Stage IV. J-PAS will detect 7× 105 galaxy clusters and groups, setting constraints on Dark Energy which rival those obtained from its BAO measurements. Thanks to the superb characteristics of the site (seeing ˜ 0.7 arcsec), J-PAS is expected to obtain a deep, sub-arcsec image of the Northern sky, which combined with its unique photo-z precision will produce one of the most powerful cosmological lensing surveys before the arrival of Euclid. J-PAS's unprecedented spectral time domain information will enable a self-contained SN survey that, without the need for external spectroscopic follow-up, will detect, classify and measure σz˜ 0.5 redshifts for ˜ 4000 SNeIa and ˜ 900 core-collapse SNe. The key to the J-PAS potential is its innovative approach: a contiguous system of 54 filters with 145 Å width, placed 100 Å apart over a multi-degree FoV is a powerful redshift machine, with the survey speed of a 4000 multiplexing low resolution spectrograph, but many times cheaper and much faster to build. The J-PAS camera is equivalent to a 4.7 sq.deg. IFU and it will produce a time-resolved, 3D image of the Northern Sky with a very wide range of Astrophysical applications in Galaxy Evolution, the nearby Universe and the study of resolved stellar populations.

  20. Expanding Cooperation between the Department of Energy (DOE) and the National Association of State Universities and Land-Grant Colleges (NASULGC)

    SciTech Connect

    Maw, Ian L.

    2006-08-01

    The DOE and the NASULGC have agreed to have closer cooperation with the purpose of expanding the access of the DOE to the research and Extension capacities of the state universities and land-grant colleges. The objective of this expanded cooperation will be to provide access to Extension and Outreach Systems for delivering products and services of the DOE research and development programs and to develop partnerships in research that will increase the productivity of DOE and NASULGC-affiliated institution research programs. NASULGC is uniquely qualified to partner with the DOE because they represent each of the institutions involved in the national extension system. Five projects have been developed to initiate the expanded cooperation between DOE/EERE and BAA/NASULGC. In some cases, these are pilot projects designed to develop information that can support broadened cooperation. They are offered for action by the BAA to the EERE Board. Agreement on the initiation of these projects will result in their implementation during the 2004 calendar year. At midyear and at the end of 2004, those responsible for each of the projects will provide an accounting of activities and assessment of results for expanding energy education, research and technical assistance. The five suggested projects are; Expanding the Opportunities for Cooperation and Communication o Advisory Boards o Meetings o EERE new hires; Use of Extension and Outreach Systems for the Dissemination and Delivery of DOE/EERE Products and Services; Youth Education in Science and Technology; Engaging the Research Capacity of NASULGC Institutions; and Workshops at the DOE Labs for Scientists from the NASULGC-Affiliated Institutions.

  1. Expanding Access for Training of Science Teachers through ODL: A Case Study of University of Lagos, Nigeria

    ERIC Educational Resources Information Center

    Okunuga, A. O.; Olaoluniyi, O.; Opara, A. I.

    2013-01-01

    Rising up to the challenge of shortage of middle manpower in Nigeria, the University of Lagos established the Correspondence and Open Studies Unit (COSU), now Distance Learning Institute DLI). Accounting, Business Administration and Science-Education were the pilot courses at the B.Sc. level. The Special Entry Preparatory Programme (SEPP) was…

  2. Expanding the Role of Institutional Research at Small Private Universities: A Case Study in Enrollment Management Using Data Mining

    ERIC Educational Resources Information Center

    Antons, Christopher M.; Maltz, Elliot N.

    2006-01-01

    This case study documents a successful application of data-mining techniques in enrollment management through a partnership between the admissions office, a business administration master's-degree program, and the institutional research office at Willamette University (Salem, Oregon). (Contains 1 table and 3 figures.)

  3. Expanding the Scope of Technical Communication: Examples from the Department of Technical Communication at the University of Washington.

    ERIC Educational Resources Information Center

    Haselkorn, Mark P.; Sauer, Geoffrey; Turns, Jennifer; Illman, Deborah L.; Tsutsui, Michio; Plumb, Carolyn; Williams, Tom; Kolko, Beth; Spyridakis, Jan

    2003-01-01

    Presents eight current projects involving faculty in the University of Washington's Department of Technical Communication that illustrate the broadening of the field. Notes these projects address: the cognitive processing of visual material; Web-based education; strategic management of information; communicating science and technology in the…

  4. Expanding the Social Frame of Knowledge: Interdisciplinary, Degree-Granting Fields in American Colleges and Universities, 1975-2000

    ERIC Educational Resources Information Center

    Brint, Steven G.; Turk-Bicakci, Lori; Proctor, Kristopher; Murphy, Scott Patrick

    2009-01-01

    The number of interdisciplinary, degree-granting fields in American colleges and universities has grown rapidly, with socially incorporative programs (women's studies, ethnic studies, and non-Western area studies) accounting for a large share. These fields have diffused widely over time, while other interdisciplinary fields have not. Variables…

  5. Expanding (3+1)-dimensional universe from a lorentzian matrix model for superstring theory in (9+1) dimensions.

    PubMed

    Kim, Sang-Woo; Nishimura, Jun; Tsuchiya, Asato

    2012-01-01

    We reconsider the matrix model formulation of type IIB superstring theory in (9+1)-dimensional space-time. Unlike the previous works in which the Wick rotation was used to make the model well defined, we regularize the Lorentzian model by introducing infrared cutoffs in both the spatial and temporal directions. Monte Carlo studies reveal that the two cutoffs can be removed in the large-N limit and that the theory thus obtained has no parameters other than one scale parameter. Moreover, we find that three out of nine spatial directions start to expand at some "critical time," after which the space has SO(3) symmetry instead of SO(9).

  6. Accelerating the commercialization of university technologies for military healthcare applications: the role of the proof of concept process

    NASA Astrophysics Data System (ADS)

    Ochoa, Rosibel; DeLong, Hal; Kenyon, Jessica; Wilson, Eli

    2011-06-01

    The von Liebig Center for Entrepreneurism and Technology Advancement at UC San Diego (vonliebig.ucsd.edu) is focused on accelerating technology transfer and commercialization through programs and education on entrepreneurism. Technology Acceleration Projects (TAPs) that offer pre-venture grants and extensive mentoring on technology commercialization are a key component of its model which has been developed over the past ten years with the support of a grant from the von Liebig Foundation. In 2010, the von Liebig Entrepreneurism Center partnered with the U.S. Army Telemedicine and Advanced Technology Research Center (TATRC), to develop a regional model of Technology Acceleration Program initially focused on military research to be deployed across the nation to increase awareness of military medical needs and to accelerate the commercialization of novel technologies to treat the patient. Participants to these challenges are multi-disciplinary teams of graduate students and faculty in engineering, medicine and business representing universities and research institutes in a region, selected via a competitive process, who receive commercialization assistance and funding grants to support translation of their research discoveries into products or services. To validate this model, a pilot program focused on commercialization of wireless healthcare technologies targeting campuses in Southern California has been conducted with the additional support of Qualcomm, Inc. Three projects representing three different universities in Southern California were selected out of forty five applications from ten different universities and research institutes. Over the next twelve months, these teams will conduct proof of concept studies, technology development and preliminary market research to determine the commercial feasibility of their technologies. This first regional program will help build the needed tools and processes to adapt and replicate this model across other regions in the

  7. The Acceleration of the Universe in the Light of Supernovae: The Key Role of CTIO

    NASA Astrophysics Data System (ADS)

    Hamuy, M.; Suntzeff, N. B.

    2015-05-01

    The discovery of acceleration and dark energy arguably constitutes the most revolutionary discovery in astrophysics in recent years. The Cerro Tololo Inter-American Observatory (CTIO) played a key role in this amazing discovery through three systematic surveys organized by staff astronomers: the “Tololo Supernova Program“ (1986-2000), the Calán/Tololo Project (1989-1993), and the “High-Z Supernova Search Team” (1994-1998). CTIO's state of the art instruments also were fundamental in the independent discovery of acceleration by the “Supernova Cosmology Project” (1992-1999). Here I summarize the work on supernovae carried out from CTIO that led to the discovery of acceleration and dark energy and provide a brief historical summary on the use of Type Ia supernovae in cosmology in order to provide context for the CTIO contribution.

  8. An Experiment in ''Less Time, More Options": A Study of Accelerated University Students.

    ERIC Educational Resources Information Center

    Litwin, James L.; And Others

    This study investigated the characteristics and experiences of 59 college students accelerated from their freshman to their junior year. The students showed high academic performance and few social problems, but questions of personal identity remained problematic; the best single predictor of academic success was found to be freshman grade-point…

  9. Restoration of accelerator facilities damaged by Great East Japan Earthquake at Cyclotron and Radioisotope Center, Tohoku University.

    PubMed

    Wakui, Takashi; Itoh, Masatoshi; Shimada, Kenzi; Yoshida, Hidetomo P; Shinozuka, Tsutomu; Sakemi, Yasuhiro

    2014-01-01

    The Cyclotron and Radioisotope Center (CYRIC) of Tohoku University is a joint-use institution for education and research in a wide variety of fields ranging from physics to medicine. Accelerator facilities at the CYRIC provide opportunities for implementing a broad research program, including medical research using positron emission tomography (PET), with accelerated ions and radioisotopes. At the Great East Japan Earthquake on March 11, 2011, no human injuries occurred and a smooth evacuation was made in the CYRIC, thanks to the anti-earthquake measures such as the renovation of the cyclotron building in 2009 mainly to provide seismic strengthening, fixation of shelves to prevent the falling of objects, and securement of the width of the evacuation route. The preparation of an emergency response manual was also helpful. However, the accelerator facilities were damaged because of strong shaking that continued for a few minutes. For example, two columns on which a 930 cyclotron was placed were damaged, and thereby the 930 cyclotron was inclined. All the elements of beam transport lines were deviated from the beam axis. Some peripheral devices in a HM12 cyclotron were broken. Two shielding doors fell from the carriage onto the floor and blocked the entrances to the rooms. The repair work on the accelerator facilities was started at the end of July 2011. During the repair work, the joint use of the accelerator facilities was suspended. After the repair work was completed, the joint use was re-started at October 2012, one and a half years after the earthquake.

  10. Universal Scalings for Direct Laser Acceleration of Relativistic Electrons in Ion Channels

    NASA Astrophysics Data System (ADS)

    Khudik, Vladimir; Arefiev, Alexey; Zhang, Xi; Shvets, Gennady

    2015-11-01

    Direct Laser Acceleration (DLA) of electrons in ion channels is investigated in the general case when the laser phase velocity is greater or equal to the speed of light, and the electrons execute a fully three-dimensional trajectory inside the focusing channel. In the paraxial limit of electron motion (mostly forward), we develop an analytic theory that provides an accurate estimate of the maximum possible energy gain of the electrons as a function of their initial conditions and laser parameters. Some of the counter-intuitive predictions validated via particle simulations include the emergence of the phase space barriers that prevent electrons from getting accelerated, and the threshold-like dependence of the energy on the initial conditions. The predictive power of the theory is demonstrated by identifying the laser-plasma parameters for the electron acceleration through the resonant interaction between the third harmonic of betatron oscillations and the laser wave. Possible experimental signatures of the high-order resonances will be discussed. This work was supported by DOE grants DESC0007889 and DE-SC0010622, and by an AFOSR grant FA9550-14-1-0045.

  11. A simple model of universe describing the early inflation and the late accelerated expansion in a symmetric manner

    SciTech Connect

    Chavanis, Pierre-Henri

    2013-07-23

    We construct a simple model of universe which 'unifies' vacuum energy and radiation on the one hand, and matter and dark energy on the other hand in the spirit of a generalized Chaplygin gas model. Specifically, the phases of early inflation and late accelerated expansion are described by a generalized equation of state p/c{sup 2} = αρ+kρ{sup 1+1/n} having a linear component p = αρc{sup 2} and a polytropic component p = kρ{sup 1+1/n}c{sup 2}. For α= 1/3, n= 1 and k=−4/(3ρ{sub P}), where ρ{sub P}= 5.1610{sup 99} g/m{sup 3} is the Planck density, this equation of state describes the transition between the vacuum energy era and the radiation era. For t≥ 0, the universe undergoes an inflationary expansion that brings it from the Planck size l{sub P}= 1.6210{sup −35} m to a size a{sub 1}= 2.6110{sup −6} m on a timescale of about 23.3 Planck times t{sub P}= 5.3910{sup −44} s (early inflation). When t > t{sub 1}= 23.3t{sub P}, the universe decelerates and enters in the radiation era. We interpret the transition from the vacuum energy era to the radiation era as a second order phase transition where the Planck constant ℏ plays the role of finite size effects (the standard Big Bang theory is recovered for ℏ= 0). For α= 0, n=−1 and k=−ρ{sub Λ}, where ρ{sub Λ}= 7.0210{sup −24} g/m{sup 3} is the cosmological density, the equation of state p/c{sup 2} = αρ+kρ{sup 1+1/n} describes the transition from a decelerating universe dominated by pressureless matter (baryonic and dark matter) to an accelerating universe dominated by dark energy (late inflation). This transition takes place at a size a{sub 2}= 0.204l{sub Λ}. corresponding to a time t{sub 2}= 0.203t{sub Λ} where l{sub Λ}= 4.38 10{sup 26} m is the cosmological length and t{sub Λ}= 1.46 10{sup 18} s the cosmological time. The present universe turns out to be just at the transition between these two periods (t{sub 0}∼t{sub 2}). Our model gives the same results as the standard

  12. A simple model of universe describing the early inflation and the late accelerated expansion in a symmetric manner

    NASA Astrophysics Data System (ADS)

    Chavanis, Pierre-Henri

    2013-07-01

    We construct a simple model of universe which "unifies" vacuum energy and radiation on the one hand, and matter and dark energy on the other hand in the spirit of a generalized Chaplygin gas model. Specifically, the phases of early inflation and late accelerated expansion are described by a generalized equation of state p/c2 = αρ+kρ1+1/n having a linear component p = αρc2 and a polytropic component p = kρ1+1/nc2. For α = 1/3, n = 1 and k = -4/(3ρP), where ρP = 5.161099 g/m3 is the Planck density, this equation of state describes the transition between the vacuum energy era and the radiation era. For t >= 0, the universe undergoes an inflationary expansion that brings it from the Planck size lP = 1.6210-35 m to a size a1 = 2.6110-6 m on a timescale of about 23.3 Planck times tP = 5.3910-44 s (early inflation). When t > t1 = 23.3tP, the universe decelerates and enters in the radiation era. We interpret the transition from the vacuum energy era to the radiation era as a second order phase transition where the Planck constant ℏ plays the role of finite size effects (the standard Big Bang theory is recovered for ℏ = 0). For α = 0, n = -1 and k = -ρΛ, where ρΛ = 7.0210-24 g/m3 is the cosmological density, the equation of state p/c2 = αρ+kρ1+1/n describes the transition from a decelerating universe dominated by pressureless matter (baryonic and dark matter) to an accelerating universe dominated by dark energy (late inflation). This transition takes place at a size a2 = 0.204lΛ. corresponding to a time t2 = 0.203tΛ where lΛ = 4.38 1026 m is the cosmological length and tΛ = 1.46 1018 s the cosmological time. The present universe turns out to be just at the transition between these two periods (t0 ~ t2). Our model gives the same results as the standard ΛCDM model for t >> tP and completes it by incorporating a phase of early inflation for t < 23.3tP in a very natural manner. Furthermore, it reveals a nice "symmetry" between the early and the late

  13. LLNL/UC (Lawrence Livermore National Laboratory)/(University of California) AMS (accelerator mass spectrometry) facility and research program

    SciTech Connect

    Davis, J.C.; Proctor, I.D.; Southon, J.R.; Caffee, M.W.; Heikkinen, D.W.; Roberts, M.L.; Moore, T.L.; Turteltaub, K.W.; Nelson, D.E.; Loyd, D.H.; Vogel, J.S.

    1990-04-18

    The Lawrence Livermore National Laboratory (LLNL) and the University of California (UC) now have in operation a large AMS spectrometer built as part of a new multiuser laboratory centered on an FN tandem. AMS measurements are expected to use half of the beam time of the accelerator. LLNL use of AMS is in research on consequences of energy usage. Examples include global warming, geophysical site characterization, radiation biology and dosimetry, and study of mutagenic and carcinogenic processes. UC research activities are in clinical applications, archaeology and anthropology, oceanography, and geophysical and geochemical research. Access is also possible for researchers outside the UC system. The technological focus of the laboratory is on achieving high rates of sample through-put, unattended operation, and advances in sample preparation methods. Because of the expected growth in the research programs and the other obligations of the present accelerator, we are designing a follow-on dedicated facility for only AMS and microprobe analysis that will contain at least two accelerators with multiple spectrometers. 10 refs., 1 fig.

  14. Java Based Tool To Explore The Discovery Of Dark Energy And The Accelerated Expansion Of The Universe

    NASA Astrophysics Data System (ADS)

    Mijic, Milan; Lim, R.; Hu, Z.; Park, D.; Wells, D.; Wong, F.; Perrault, S.; Shvarts, E.; Levitin, S.; Rios, M.; Kang, E. Y. E.; Longson, T.

    2008-05-01

    The discovery of the accelerated expansion of the universe through observations of High-Redshift supernovae and its implication for the existence of Dark Energy as the dominant component of our universe, surely counts as one of the most important moments in the entire history of physics and astronomy. This discovery has great appeal to the general public, both because of the heroic lore to observe distant supernovae and because of the strange relativistic properties of the Dark Energy. To bring this development to the non-professionals, the Cal State L.A. Science Visualization project developed an easy to use Java based tool, which may be used in college, pre-college or public science education. The tool utilizes multimedia presentations, such as graphs or images, to simulate the search for and observations of high-redshift supernovae, and interactively leads to the discovery of the created universe fluid content. Model universes are selected in a semi-random manner, which displays range of interesting possibilities for the effective equation of state, the shape of the Hubble diagram, or the nature of the expansion. The Java-based tool is deployed through Java webstart for both high-end and low-end terminal users across platforms.

  15. Open FRW universes and self-acceleration from nonlinear massive gravity

    SciTech Connect

    Gümrükçüoğlu, A. Emir; Lin, Chunshan; Mukohyama, Shinji E-mail: chunshan.lin@ipmu.jp

    2011-11-01

    In the context of a recently proposed nonlinear massive gravity with Lorentz-invariant mass terms, we investigate open Friedmann-Robertson-Walker (FRW) universes driven by arbitrary matter source. While the flat FRW solutions were recently shown to be absent, the proof does not extend to the open universes. We find three independent branches of solutions to the equations of motion for the Stückelberg scalars. One of the branches does not allow any nontrivial FRW cosmologies, as in the previous no-go result. On the other hand, both of the other two branches allow general open FRW universes governed by the Friedmann equation with the matter source, the standard curvature term and an effective cosmological constant Λ{sub ±} = c{sub ±}m{sub g}{sup 2}. Here, m{sub g} is the graviton mass, + and - represent the two branches, and c{sub ±} are constants determined by the two dimensionless parameters of the theory. Since an open FRW universe with a sufficiently small curvature constant can approximate a flat FRW universe but there is no exactly flat FRW solution, the theory exhibits a discontinuity at the flat FRW limit.

  16. Accelerators/decelerators of achieving universal access to sexual and reproductive health services: a case study of Iranian health system

    PubMed Central

    2013-01-01

    Background At the 1994 International Conference on Population and Development (ICPD), held in Cairo, the global community agreed to the goal of achieving universal access to sexual and reproductive health (SRH) and rights by 2015. This research explores the accelerators and decelerators of achieving universal access to the sexual and reproductive health targets and accordingly makes some suggestions. Method We have critically reviewed the latest national reports and extracted the background data on each SRH indicator. The key stakeholders, both national and international, were visited and interviewed at two sites. A total of 55 in-depth interviews were conducted with religious leaders, policy-makers, senior managers, senior academics, and health care managers. Six focus-group discussions were also held among health care providers. The study was qualitative in nature. Results Obstacles on the road to achieving universal access to SRH can be viewed from two perspectives. One gap exists between current achievements and the targets. The other gap arises due to age, marital status, and residency status. The most recently observed trends in the indicators of the universal access to SRH shows that the achievements in the “unmet need for family planning” have been poor. Unmet need for family planning could directly be translated to unwanted pregnancies and unwanted childbirths; the former calls for sexual education to underserved people, including adolescents; and the latter calls for access to safe abortion. Local religious leaders have not actively attended international goal-setting programs. Therefore, they usually do not presume a positive attitude towards these goals. Such negative attitudes seem to be the most important factors hindering the progress towards universal access to SRH. Lack of international donors to fund for SRH programs is also another barrier. In national levels both state and the society are interactively playing their roles. We have used a

  17. Can a matter-dominated model with constant bulk viscosity drive the accelerated expansion of the universe?

    SciTech Connect

    Avelino, Arturo; Nucamendi, Ulises E-mail: ulises@ifm.umich.mx

    2009-04-15

    We test a cosmological model which the only component is a pressureless fluid with a constant bulk viscosity as an explanation for the present accelerated expansion of the universe. We classify all the possible scenarios for the universe predicted by the model according to their past, present and future evolution and we test its viability performing a Bayesian statistical analysis using the SCP ''Union'' data set (307 SNe Ia), imposing the second law of thermodynamics on the dimensionless constant bulk viscous coefficient {zeta}-tilde and comparing the predicted age of the universe by the model with the constraints coming from the oldest globular clusters. The best estimated values found for {zeta}-tilde and the Hubble constant H{sub 0} are: {zeta}-tilde = 1.922{+-}0.089 and H{sub 0} = 69.62{+-}0.59 (km/s)Mpc{sup -1} with a {chi}{sup 2}{sub min} = 314 ({chi}{sup 2}{sub d.o.f} = 1.031). The age of the universe is found to be 14.95{+-}0.42 Gyr. We see that the estimated value of H{sub 0} as well as of {chi}{sup 2}{sub d.o.f} are very similar to those obtained from {Lambda}CDM model using the same SNe Ia data set. The estimated age of the universe is in agreement with the constraints coming from the oldest globular clusters. Moreover, the estimated value of {zeta}-tilde is positive in agreement with the second law of thermodynamics (SLT). On the other hand, we perform different forms of marginalization over the parameter H{sub 0} in order to study the sensibility of the results to the way how H{sub 0} is marginalized. We found that it is almost negligible the dependence between the best estimated values of the free parameters of this model and the way how H{sub 0} is marginalized in the present work. Therefore, this simple model might be a viable candidate to explain the present acceleration in the expansion of the universe.

  18. A Co-Investigator Project for the Cornell University Cleft Accelerated Plasma Experimental Rocket-CAPER

    NASA Technical Reports Server (NTRS)

    Deehr, Charles S.

    1999-01-01

    The CAPER rocket campaign was to follow the SCIFER experiment as a detailed study of the ion acceleration processes in the Cleft Ion Fountain (CIF) above 1000 km altitude. The SCIFER rocket demonstrated that the experiment was feasible and that the CIF acceleration processes on the dayside are different from those observed in the discrete aurora on the nightside. The responsibility of the GI/UAF co-investigator project was to provide the real-time acquisition and display of large-and small-scale ground observations, and satellite solar wind data at the launch control center at Longyearbyen, Svalbard for the determination of the launch conditions and the later interpretation of the rocket observations. The rocket campaign was proposed for January of 1998, but was slipped to January of 1999. The rocket was launched on January 21, 1999 at 06 h 13 m 30 s UT. All of the GI/UAF co-investigator systems functioned well, except the narrow-field TV camera which was to follow the 140 km conjugate of the payload on command from GPS tracking data sent from Andoya. The data were not available during the flight, and the camera tracked the nominal conjugate. Unfortunately, the trajectory was well west of nominal, so no useful narrow-field conjugate data were acquired . In addition, the payload missed the region of more intense precipitation, brighter aurora, stronger currents, and likely large fluxes of transverse ion acceleration. On the other hand, good data were acquired across a region of the ionosphere that appears to have had a double convection boundary because of the IMF switching its z component shortly before launch. These data are important for understanding the reaction of the magnetosphere and ionosphere to changes in the IMF.

  19. Uniformly expanding vacuum: A possible interpretation of the dark energy

    NASA Astrophysics Data System (ADS)

    Huang, Peng; Yuan, Fang-Fang

    2016-06-01

    Following the spirit of the equivalence principle, we take a step further to recognize the free fall of the observer as a method to eliminate causes that would lead the perceived vacuum to change its original state. Thus, it is expected that the vacuum should be in a rigid Minkowski state or be uniformly expanding. By carefully investigating the impact on measurement caused by the expansion, we clarify the exact meaning of the uniformly expanding vacuum and find that this proposal may be able to explain the current observations of an accelerating universe.

  20. Can Accelerators Accelerate Learning?

    NASA Astrophysics Data System (ADS)

    Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.

    2009-03-01

    The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ) [1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.

  1. Can Accelerators Accelerate Learning?

    SciTech Connect

    Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.

    2009-03-10

    The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ)[1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.

  2. The Expanding Universe: Dark Energy

    ERIC Educational Resources Information Center

    Lincoln, Don; Nord, Brian

    2014-01-01

    As is true of a far more famous story, it all began a long time ago, in a galaxy far, far away. It even involved a binary star system. A small star, called a white dwarf, had become a burned out husk of its former self and it turned to gorging on hydrogen and helium from its bloated red giant neighbor. The transferred gas reignited the fires of…

  3. Comments on an Expanding Universe

    SciTech Connect

    Samuel, Stuart; Samuel, Stuart

    2005-12-12

    Various results are obtained for a Friedmann-Robertson-Walker cosmology. We derive an exact equation that determines Hubble's law, clarify issues concerning the speeds of faraway objects and uncover a 'tail-light angle effect' for distant luminous sources. The latter leads to a small, previously unnoticed correction to the parallax distance formula.

  4. The "expanding universe" of piroplasms.

    PubMed

    Criado-Fornelio, A; Gónzalez-del-Río, M A; Buling-Saraña, A; Barba-Carretero, J C

    2004-02-01

    The present paper is the continuation of our previous studies dealing with the genetic characterization of piroplasmid species found in southern Europe. We report in this work new data concerning sequences of the 18s rRNA gene in Spanish piroplasms not studied (or not totally sequenced) in our former surveys. Molecular data analysis indicated that Spanish Cytauxzoon felis (cat isolate) has 98% identity with Cytauxzoon sp. from Mongolia and 95% identity compared to African C. felis. There are at least two main genetic variants of Babesia caballi in Spain: The first variety (isolate Spain 1) shows a relatively low homology with the African genotype (97% identity). The second variety (represented by two isolates, Spain 2 and Spain 3, differing by a single base) shows high genetic similarity with the African genotype (99.7-100% identity). There are also two genetic variants of Babesia equi (isolates Spain 1 and Spain 2, differing by four bases) in Spain, sharing 99% identity with the African genotype. At least one of them (Spain 1) can infect dogs. All of the phylogenetic analysis procedures employed indicated that Spanish isolates of C. felis, B. caballi (Spain 1) and B. equi (Spain 1 and Spain 2) are genetically different from their African relatives, all those dichotomies showing very high bootstrap support. Nonetheless, the lack of information on their morphology and the fact that the sequences were obtained in a single isolate preclude any conclusion about their definitive taxonomic status.

  5. The expanding universe of hypoxia.

    PubMed

    Zhang, Huafeng; Semenza, Gregg L

    2008-07-01

    Reduced oxygen availability (hypoxia) is sensed and transduced into changes in the activity or expression of cellular macromolecules. These responses impact on virtually all areas of biology and medicine. In this meeting report, we summarize major developments in the field that were presented at the 2008 Keystone Symposium on Cellular, Physiological, and Pathogenic Responses to Hypoxia.

  6. Misconceptions about an Expanding Universe

    SciTech Connect

    Samuel, Stuart; /SLAC /LBL, Berkeley

    2005-12-14

    Various results are obtained for a Friedmann-Robertson-Walker cosmology. We derive an exact equation that determines Hubble's law, clarify issues concerning the speeds of faraway objects and uncover a ''tail-light angle effect'' for distant luminous sources. The latter leads to a small, previously unnoticed correction to the parallax distance formula.

  7. Advances in boron neutron capture therapy (BNCT) at kyoto university - From reactor-based BNCT to accelerator-based BNCT

    NASA Astrophysics Data System (ADS)

    Sakurai, Yoshinori; Tanaka, Hiroki; Takata, Takushi; Fujimoto, Nozomi; Suzuki, Minoru; Masunaga, Shinichiro; Kinashi, Yuko; Kondo, Natsuko; Narabayashi, Masaru; Nakagawa, Yosuke; Watanabe, Tsubasa; Ono, Koji; Maruhashi, Akira

    2015-07-01

    At the Kyoto University Research Reactor Institute (KURRI), a clinical study of boron neutron capture therapy (BNCT) using a neutron irradiation facility installed at the research nuclear reactor has been regularly performed since February 1990. As of November 2014, 510 clinical irradiations were carried out using the reactor-based system. The world's first accelerator-based neutron irradiation system for BNCT clinical irradiation was completed at this institute in early 2009, and the clinical trial using this system was started in 2012. A shift of BCNT from special particle therapy to a general one is now in progress. To promote and support this shift, improvements to the irradiation system, as well as its preparation, and improvements in the physical engineering and the medical physics processes, such as dosimetry systems and quality assurance programs, must be considered. The recent advances in BNCT at KURRI are reported here with a focus on physical engineering and medical physics topics.

  8. Accelerated Schools Centers: How To Address Challenges to Institutionalization and Growth.

    ERIC Educational Resources Information Center

    Meza, James, Jr.

    The Accelerated Schools Project (ASP) at the University of New Orleans (UNO) was established in spring 1990, funded by a 3-year grant from Chevron. Beginning with 1 pilot school in 1991, the UNO Accelerated Schools Center has expanded to 36 schools representing 19 school districts in Louisiana and 3 schools from the Memphis City Schools district.…

  9. Probing the accelerating Universe with redshift-space distortions in VIPERS

    NASA Astrophysics Data System (ADS)

    de la Torre, Sylvain

    2016-10-01

    We present the first measurement of the growth rate of structure at z=0.8. It has been obtained from the redshift-space distortions observed in the galaxy clustering pattern in the VIMOS Public Redshift survey (VIPERS) first data release. VIPERS is a large galaxy redshift survey probing the large-scale structure at 0.5 < z < 1.2 with an unprecedented accuracy. This measurement represents a new reference in the distant Universe, which has been poorly explored until now. We obtain σ8 = 0.47 +/- 0.08 at z = 0.8 that is consistent with the predictions of standard cosmological models based on Einstein gravity. This measurement alone is however not accurate enough to allow the detection of possible deviations from standard gravity.

  10. The André E. Lalonde AMS Laboratory - The new accelerator mass spectrometry facility at the University of Ottawa

    NASA Astrophysics Data System (ADS)

    Kieser, W. E.; Zhao, X.-L.; Clark, I. D.; Cornett, R. J.; Litherland, A. E.; Klein, M.; Mous, D. J. W.; Alary, J.-F.

    2015-10-01

    The University of Ottawa, Canada, has installed a multi-element, 3 MV tandem AMS system as the cornerstone of their new Advanced Research Complex and the principal analytical instrument of the André E. Lalonde Accelerator Mass Spectrometry Laboratory. Manufactured by High Voltage Engineering Europa B.V., the Netherlands, it is equipped with a 200 sample ion source, a high resolution, 120° injection magnet, a 90° high energy analysis magnet (mass-energy product 350 MeV-AMU), a 65°, 1.7 m radius electric analyzer and a 2 channel gas ionization detector. It is designed to analyze isotopes ranging from tritium to the actinides and to accommodate the use of fluoride target materials. This system is being extended with a second injection line, consisting of selected components from the IsoTrace Laboratory, University of Toronto. This line will contain a pre-commercial version of the Isobar Separator for Anions, manufactured by Isobarex Corp., Bolton, Ontario, Canada. This instrument uses selective ion-gas reactions in a radio-frequency quadrupole cell to attenuate both atomic and molecular isobars. This paper discusses the specifications of the new AMS equipment, reports on the acceptance test results for 10Be, 14C, 26Al and 127I and presents typical spectra for 10Be and actinide analyses.

  11. Using Dark Matter Haloes to Learn about Cosmic Acceleration: A New Proposal for a Universal Mass Function

    NASA Technical Reports Server (NTRS)

    Prescod-Weinstein, Chanda; Afshordi, Niayesh

    2011-01-01

    Structure formation provides a strong test of any cosmic acceleration model because a successful dark energy model must not inhibit or overpredict the development of observed large-scale structures. Traditional approaches to studies of structure formation in the presence of dark energy or a modified gravity implement a modified Press-Schechter formalism, which relates the linear overdensities to the abundance of dark matter haloes at the same time. We critically examine the universality of the Press-Schechter formalism for different cosmologies, and show that the halo abundance is best correlated with spherical linear overdensity at 94% of collapse (or observation) time. We then extend this argument to ellipsoidal collapse (which decreases the fractional time of best correlation for small haloes), and show that our results agree with deviations from modified Press-Schechter formalism seen in simulated mass functions. This provides a novel universal prescription to measure linear density evolution, based on current and future observations of cluster (or dark matter) halo mass function. In particular, even observations of cluster abundance in a single epoch will constrain the entire history of linear growth of cosmological of perturbations.

  12. Expanding the spectrum of phenotypes associated with germline PIGA mutations: a child with developmental delay, accelerated linear growth, facial dysmorphisms, elevated alkaline phosphatase, and progressive CNS abnormalities.

    PubMed

    van der Crabben, Saskia N; Harakalova, Magdalena; Brilstra, Eva H; van Berkestijn, Frédérique M C; Hofstede, Floris C; van Vught, Adrianus J; Cuppen, Edwin; Kloosterman, Wigard; Ploos van Amstel, Hans Kristian; van Haaften, Gijs; van Haelst, Mieke M

    2014-01-01

    Phosphatidyl inositol glycan (PIG) enzyme subclasses are involved in distinct steps of glycosyl phosphatidyl inositol anchor protein biosynthesis. Glycolsyl phosphatidyl inositol-anchored proteins have heterogeneous functions; they can function as enzymes, adhesion molecules, complement regulators and co-receptors in signal transduction pathways. Germline mutations in genes encoding different members of the PIG family result in diverse conditions with (severe) developmental delay, (neonatal) seizures, hypotonia, CNS abnormalities, growth abnormalities, and congenital abnormalities as hallmark features. The variability of clinical features resembles the typical diversity of other glycosylation pathway deficiencies such as the congenital disorders of glycosylation. Here, we report the first germline missense mutation in the PIGA gene associated with accelerated linear growth, obesity, central hypotonia, severe refractory epilepsy, cardiac anomalies, mild facial dysmorphic features, mildly elevated alkaline phosphatase levels, and CNS anomalies consisting of progressive cerebral atrophy, insufficient myelinization, and cortical MRI signal abnormalities. X-exome sequencing in the proband identified a c.278C>T (p.Pro93Leu) mutation in the PIGA gene. The mother and maternal grandmother were unaffected carriers and the mother showed 100% skewing of the X-chromosome harboring the mutation. These results together with the clinical similarity of the patient reported here and the previously reported patients with a germline nonsense mutation in PIGA support the determination that this mutation caused the phenotype in this family.

  13. Expanding the spectrum of phenotypes associated with germline PIGA mutations: a child with developmental delay, accelerated linear growth, facial dysmorphisms, elevated alkaline phosphatase, and progressive CNS abnormalities.

    PubMed

    van der Crabben, Saskia N; Harakalova, Magdalena; Brilstra, Eva H; van Berkestijn, Frédérique M C; Hofstede, Floris C; van Vught, Adrianus J; Cuppen, Edwin; Kloosterman, Wigard; Ploos van Amstel, Hans Kristian; van Haaften, Gijs; van Haelst, Mieke M

    2014-01-01

    Phosphatidyl inositol glycan (PIG) enzyme subclasses are involved in distinct steps of glycosyl phosphatidyl inositol anchor protein biosynthesis. Glycolsyl phosphatidyl inositol-anchored proteins have heterogeneous functions; they can function as enzymes, adhesion molecules, complement regulators and co-receptors in signal transduction pathways. Germline mutations in genes encoding different members of the PIG family result in diverse conditions with (severe) developmental delay, (neonatal) seizures, hypotonia, CNS abnormalities, growth abnormalities, and congenital abnormalities as hallmark features. The variability of clinical features resembles the typical diversity of other glycosylation pathway deficiencies such as the congenital disorders of glycosylation. Here, we report the first germline missense mutation in the PIGA gene associated with accelerated linear growth, obesity, central hypotonia, severe refractory epilepsy, cardiac anomalies, mild facial dysmorphic features, mildly elevated alkaline phosphatase levels, and CNS anomalies consisting of progressive cerebral atrophy, insufficient myelinization, and cortical MRI signal abnormalities. X-exome sequencing in the proband identified a c.278C>T (p.Pro93Leu) mutation in the PIGA gene. The mother and maternal grandmother were unaffected carriers and the mother showed 100% skewing of the X-chromosome harboring the mutation. These results together with the clinical similarity of the patient reported here and the previously reported patients with a germline nonsense mutation in PIGA support the determination that this mutation caused the phenotype in this family. PMID:24259184

  14. Accelerating health equity: the key role of universal health coverage in the Sustainable Development Goals.

    PubMed

    Tangcharoensathien, Viroj; Mills, Anne; Palu, Toomas

    2015-01-01

    The Sustainable Development Goals (SDGs), to be committed to by Heads of State at the upcoming 2015 United Nations General Assembly, have set much higher and more ambitious health-related goals and targets than did the Millennium Development Goals (MDGs). The main challenge among MDG off-track countries is the failure to provide and sustain financial access to quality services by communities, especially the poor. Universal health coverage (UHC), one of the SDG health targets indispensable to achieving an improved level and distribution of health, requires a significant increase in government investment in strengthening primary healthcare - the close-to-client service which can result in equitable access. Given the trend of increased fiscal capacity in most developing countries, aiming at long-term progress toward UHC is feasible, if there is political commitment and if focused, effective policies are in place. Trends in high income countries, including an aging population which increases demand for health workers, continue to trigger international migration of health personnel from low and middle income countries. The inspirational SDGs must be matched with redoubled government efforts to strengthen health delivery systems, produce and retain more and relevant health workers, and progressively realize UHC. PMID:25925656

  15. Accelerating health equity: the key role of universal health coverage in the Sustainable Development Goals.

    PubMed

    Tangcharoensathien, Viroj; Mills, Anne; Palu, Toomas

    2015-04-29

    The Sustainable Development Goals (SDGs), to be committed to by Heads of State at the upcoming 2015 United Nations General Assembly, have set much higher and more ambitious health-related goals and targets than did the Millennium Development Goals (MDGs). The main challenge among MDG off-track countries is the failure to provide and sustain financial access to quality services by communities, especially the poor. Universal health coverage (UHC), one of the SDG health targets indispensable to achieving an improved level and distribution of health, requires a significant increase in government investment in strengthening primary healthcare - the close-to-client service which can result in equitable access. Given the trend of increased fiscal capacity in most developing countries, aiming at long-term progress toward UHC is feasible, if there is political commitment and if focused, effective policies are in place. Trends in high income countries, including an aging population which increases demand for health workers, continue to trigger international migration of health personnel from low and middle income countries. The inspirational SDGs must be matched with redoubled government efforts to strengthen health delivery systems, produce and retain more and relevant health workers, and progressively realize UHC.

  16. The High Time Resolution Universe Pulsar Survey - XII. Galactic plane acceleration search and the discovery of 60 pulsars

    NASA Astrophysics Data System (ADS)

    Ng, C.; Champion, D. J.; Bailes, M.; Barr, E. D.; Bates, S. D.; Bhat, N. D. R.; Burgay, M.; Burke-Spolaor, S.; Flynn, C. M. L.; Jameson, A.; Johnston, S.; Keith, M. J.; Kramer, M.; Levin, L.; Petroff, E.; Possenti, A.; Stappers, B. W.; van Straten, W.; Tiburzi, C.; Eatough, R. P.; Lyne, A. G.

    2015-07-01

    We present initial results from the low-latitude Galactic plane region of the High Time Resolution Universe pulsar survey conducted at the Parkes 64-m radio telescope. We discuss the computational challenges arising from the processing of the terabyte-sized survey data. Two new radio interference mitigation techniques are introduced, as well as a partially coherent segmented acceleration search algorithm which aims to increase our chances of discovering highly relativistic short-orbit binary systems, covering a parameter space including potential pulsar-black hole binaries. We show that under a constant acceleration approximation, a ratio of data length over orbital period of ≈0.1 results in the highest effectiveness for this search algorithm. From the 50 per cent of data processed thus far, we have redetected 435 previously known pulsars and discovered a further 60 pulsars, two of which are fast-spinning pulsars with periods less than 30 ms. PSR J1101-6424 is a millisecond pulsar whose heavy white dwarf (WD) companion and short spin period of 5.1 ms indicate a rare example of full-recycling via Case A Roche lobe overflow. PSR J1757-27 appears to be an isolated recycled pulsar with a relatively long spin period of 17 ms. In addition, PSR J1244-6359 is a mildly recycled binary system with a heavy WD companion, PSR J1755-25 has a significant orbital eccentricity of 0.09 and PSR J1759-24 is likely to be a long-orbit eclipsing binary with orbital period of the order of tens of years. Comparison of our newly discovered pulsar sample to the known population suggests that they belong to an older population. Furthermore, we demonstrate that our current pulsar detection yield is as expected from population synthesis.

  17. Assessing the Impact of the Cambridge International Acceleration Program on U.S. University Determinants of Success: A Multi-Level Modeling Approach

    ERIC Educational Resources Information Center

    Shaw, Stuart; Warren, Jayne; Gill, Tim

    2014-01-01

    This article focuses on the research being conducted by Cambridge International Examinations (Cambridge) to ensure that its international assessments prepare students as well as other acceleration programs for continued study in U.S. colleges and universities. The study, which builds on previous freshman GPA data modeling work using data supplied…

  18. Hydrodynamic vacuum sources of dark matter self-generation in an accelerating universe without a Big Bang

    SciTech Connect

    Chefranov, S. G.; Novikov, E. A.

    2010-11-15

    these dark matter particles. Good quantitative agreement of this exact solution with the cosmological observations of SnIa, SDSS-BAO, and the decrease in the acceleration of the expansion of the Universe has been obtained.

  19. Environmental Assessment for US Department of Energy support of an Iowa State University Linear Accelerator Facility at Ames, Iowa

    SciTech Connect

    Not Available

    1990-05-01

    The proposed Department of Energy (DOE) action is financial and technical support of construction and initial operation of an agricultural commodity irradiator (principally for meat), employing a dual mode electron beam generator capable of producing x-rays, at the Iowa State University Linear Accelerator located at Ames, Iowa. The planned pilot commercial-scale facility would be used for the following activities: conducting irradiation research on agricultural commodities, principally meats; in the future, after the pilot phase, as schedules permit, possibly conducting research on other, non-edible materials; evaluating effects of irradiation on nutritional and sensory quality of agricultural products; demonstrating the efficiency of the process to control or eliminate pathogens, and/or to prolong the commodities' post-harvest shelf-life via control or elimination of bacteria, fungi, and/or insects; providing information to the public on the benefits, safety and risks of irradiated agricultural commodities; determining consumer acceptability of the irradiated products; providing data for use by regulatory agencies in developing protocols for various treatments of Iowa agricultural commodities; and training operators, maintenance and quality control technicians, scientists, engineers, and staff of regulatory agencies in agricultural commodity irradiation technology. 14 refs., 5 figs.

  20. [Projects to accelerate the practical use of innovative medical devices to collaborate with TWIns, Center for Advanced Biomedical Sciences, Waseda University and School of Engineering, The University of Tokyo].

    PubMed

    Niimi, Shingo; Umezu, Mitsuo; Iseki, Hiroshi; Harada, Hiroshi Kasanuki Noboru; Mitsuishi, Mamoru; Kitamori, Takehiko; Tei, Yuichi; Nakaoka, Ryusuke; Haishima, Yuji

    2014-01-01

    Division of Medical Devices has been conducting the projects to accelerate the practical use of innovative medical devices to collaborate with TWIns, Center for Advanced Biomedical Sciences, Waseda University and School of Engineering, The University of Tokyo. The TWIns has been studying to aim at establishment of preclinical evaluation methods by "Engineering Based Medicine", and established Regulatory Science Institute for Medical Devices. School of Engineering, The University of Tokyo has been studying to aim at establishment of assessment methodology for innovative minimally invasive therapeutic devices, materials, and nanobio diagnostic devices. This report reviews the exchanges of personnel, the implement systems and the research progress of these projects.

  1. Constraints on cosmological models and reconstructing the acceleration history of the Universe with gamma-ray burst distance indicators

    SciTech Connect

    Liang Nan; Wu Puxun; Zhang Shuangnan

    2010-04-15

    Gamma-ray bursts (GRBs) have been regarded as standard candles at very high redshift for cosmology research. We have proposed a new method to calibrate GRB distance indicators with Type Ia supernova (SNe Ia) data in a completely cosmology-independent way to avoid the circularity problem that had limited the direct use of GRBs to probe cosmology [N. Liang, W. K. Xiao, Y. Liu, and S. N. Zhang, Astrophys. J. 685, 354 (2008).]. In this paper, a simple method is provided to combine GRB data into the joint observational data analysis to constrain cosmological models; in this method those SNe Ia data points used for calibrating the GRB data are not used to avoid any correlation between them. We find that the {Lambda}CDM model is consistent with the joint data in the 1-{sigma} confidence region, using the GRB data at high redshift calibrated with the interpolating method, the Constitution set of SNe Ia, the cosmic microwave background radiation from Wilkinson Microwave Anisotropy Probe five year observation, the baryonic acoustic oscillation from the spectroscopic Sloan Digital Sky Survey Data Release 7 galaxy sample, the x-ray baryon mass fraction in clusters of galaxies, and the observational Hubble parameter versus redshift data. Comparing to the joint constraints with GRBs and without GRBs, we find that the contribution of GRBs to the joint cosmological constraints is a slight shift in the confidence regions of cosmological parameters to better enclose the {Lambda}CDM model. Finally, we reconstruct the acceleration history of the Universe up to z>6 with the distance moduli of SNe Ia and GRBs and find some features that deviate from the {Lambda}CDM model and seem to favor oscillatory cosmology models; however, further investigations are needed to better understand the situation.

  2. Expanded Yegua

    SciTech Connect

    Hart, R.E.; Grayson, S.; Benes, J.

    1988-01-01

    The upper Eocene Yegua Formation expands dramatically across a regional flexure generally 12-15 km wide. During each of several postulated Yegua sea level drops, this flexure became a focal point for deltaic deposition of good to excellent reservoir-quality sands. From the western edge of the Houston salt dome basin to the San Marcos arch, this trend has yielded, since 1982, at least seven noteworthy discoveries: Toro Grande and Lost Bridge fields in Jackson County, and Black Owl, Shanghai, Shanghai East, El Campo, and Phase Four fields in Wharton County, Texas. El Campo field in Wharton County, Texas, was discovered in December 1985 by Ladd Petroleum Corporation with the drilling of the Ladd Petroleum 1 Popp well. Mud logs acquired while drilling indicated that a very sandy reservoir, with encouraging quantities of natural gas and condensate had been encountered. Subsequent open-hold logging generated more questions than answers about the prospective sand section. Additional open hole logs (EPT/ML,SHDT) were run to identify what turned out to be an extremely laminated sand-shale sequence over 400 ft thick. Subsequent development drilling and the acquisition of a 120 ft whole core provided valuable data in analyzing this prolific, geopressured natural gas and condensate Yegua reservoir. Whole-core data, open-hole logs, and computer logs were integrated to develop petro-physical evaluation procedures and to determine the environment of deposition. El Campo field is believed to represent an extremely thick, delta front slope to distal delta front facies.

  3. The Expanding Frontier of Pluralism.

    ERIC Educational Resources Information Center

    King, Edmund

    1983-01-01

    Looks at the expanding frontier of pluralism in terms of reappraising the relationship of formal education to the advent of the constant change (occupational and social) accelerated by the microprocessor revolution and readjusting provisions in educational systems to meet the different needs of different populations. (AH)

  4. Cosmic evolution in a cyclic universe

    NASA Astrophysics Data System (ADS)

    Steinhardt, Paul J.; Turok, Neil

    2002-06-01

    Based on concepts drawn from the ekpyrotic scenario and M theory, we elaborate our recent proposal of a cyclic model of the universe. In this model, the universe undergoes an endless sequence of cosmic epochs which begin with the universe expanding from a ``big bang'' and end with the universe contracting to a ``big crunch.'' Matching from ``big crunch'' to ``big bang'' is performed according to the prescription recently proposed with Khoury, Ovrut and Seiberg. The expansion part of the cycle includes a period of radiation and matter domination followed by an extended period of cosmic acceleration at low energies. The cosmic acceleration is crucial in establishing the flat and vacuous initial conditions required for ekpyrosis and for removing the entropy, black holes, and other debris produced in the preceding cycle. By restoring the universe to the same vacuum state before each big crunch, the acceleration ensures that the cycle can repeat and that the cyclic solution is an attractor.

  5. Integrating knowledge-based systems into operations at the McMaster University FN tandem accelerator laboratory

    SciTech Connect

    Poehlman, W.F.S. ); Stark, J.W. . Tandem Accelerator Lab.)

    1989-10-01

    The introduction of computer-based expertise in accelerator operations has resulted in the development of an Accelerator Operators' Companion which incorporates a knowledge-based front-end that is tuned to user operational expertise. The front-end also provides connections to traditional software packages such as database and spreadsheet programs. During work on the back-end, that is, real-time expert system control development, the knowledge engineering phase has revealed the importance of modifying expert procedures when a multitasking environment is involved.

  6. U.S. College and University Initiatives To Expand Educational Opportunities for Black South Africans: A Models Workshop. Information Exchange: Working Paper #3.

    ERIC Educational Resources Information Center

    Micou, Ann McKinstry, Ed.

    In 1979 the Institute of International Education (IIE), a nonprofit organization that works on education programs in 145 countries and with U.S. colleges and universities, began a scholarship program for black South Africans wanting to study in the United States. The models workshop, held at the offices of the IIE in 1987, was made possible by the…

  7. Expanding the Scope of Anatomical Sciences: The Case of "Human Evolution--The Fossil Evidence" Course at the Sackler School of Medicine, Tel-Aviv University

    ERIC Educational Resources Information Center

    Notzer, Netta; Abramovitz, Ruth

    2012-01-01

    The Anatomy Department at Tel-Aviv University Medical School offers its students an elective course of 26 didactic hours on human evolution. The course is open to students from all faculties, who must fulfill all academic requirements, without a prerequisite of a background in anatomy. Approximately 120 students attend annually, a third of them…

  8. Low energy highly charged ion beam facility at Inter University Accelerator Centre: Measurement of the plasma potential and ion energy distributions

    SciTech Connect

    Sairam, T. Bhatt, Pragya; Safvan, C. P.; Kumar, Ajit; Kumar, Herendra

    2015-11-15

    A deceleration lens coupled to one of the beam lines of the electron cyclotron resonance based low energy beam facility at Inter University Accelerator Centre is reported. This system is capable of delivering low energy (2.5 eV/q–1 keV/q) highly charged ion beams. The presence of plasma potential hinders the measurements of low energies (<50 eV), therefore, plasma potential measurements have been undertaken using a retarding plate analyzer in unison with the deceleration assembly. The distributions of the ion energies have been obtained and the effect of different source parameters on these distributions is studied.

  9. Lemaître, the expanding universe, and the cosmological constant (German Title: Lemaître, das expandierende Universum und die kosmologische Konstante )

    NASA Astrophysics Data System (ADS)

    Roessler, Kurt

    The scientific and human relations of Albert Einstein and Georges Lemaître are discussed. In 1927 the later had interpreted the general theory of relativity for a model of an expanding cosmos using a positive value of the cosmological constant. In the three open questions between them: expansion of cosmos, primordial state of a quantum vacuum (``primeval atom''), importance of the cosmological constant for vacuum energy, Lemaître finally won over the heavily opposing Einstein. The philosophical and ontological tendency of Einstein's thinking was contrasted with the strict epistemological line of the catholic priest Lemaître. The dramatic changes between friendship and controversy finally led to a diminution of Lemaître's reputation as ``Darwin of Cosmology''. In that case, the late Einstein proved to be a hindrance rather than a promoter of evolution in cosmology.

  10. Expanding the Concept of Literacy.

    ERIC Educational Resources Information Center

    Daley, Elizabeth

    2003-01-01

    Explores four arguments for an expanded definition of literacy to include the multimedia language of the screen. Describes efforts to develop this literacy in students at the Institute for Multimedia Literacy at the Annenberg Center of the University of Southern California. (EV)

  11. Unsolved Mysteries of Science: A Mind-Expanding Journey through a Universe of Big Bangs, Particle Waves, and Other Perplexing Concepts

    NASA Astrophysics Data System (ADS)

    Malone, John

    2001-08-01

    A LIVELY EXPLORATION OF THE BIGGEST QUESTIONS IN SCIENCE How Did the Universe Begin? The Big Bang has been the accepted theory for decades, but does it explain everything? How Did Life on Earth Get Started? What triggered the cell division that started the evolutionary chain? Did life come from outer space, buried in a chunk of rock? What is Gravity? Newton's apple just got the arguments started, Einstein made things more complicated. Just how does gravity fit in with quantum theory? What Is the Inside of the Earth Like? What exactly is happening beneath our feet, and can we learn enough to help predict earthquakes and volcanic eruptions? How Do We Learn Language? Is language acquisition an inborn biological ability, or does every child have to start from scratch? Is There a Missing Link? The story of human evolution is not complete. In addition to hoaxes such as "Piltdown Man" and extraordinary finds such as "Lucy," many puzzles remain. What, in the end, do we mean by a "missing link"?

  12. Thermal neutron fluence in a treatment room with a Varian linear accelerator at a medical university hospital

    NASA Astrophysics Data System (ADS)

    Liu, Wen-Shan; Changlai, Sheng-Pin; Pan, Lung-Kwang; Tseng, Hsien-Chun; Chen, Chien-Yi

    2011-09-01

    The indium foil activation technique has been employed to measure thermal neutron fluences ( Φth) among various locations in the treatment room with a 20×20 cm 2 field size and a 15 and 10 MV X-ray beam. Spatial Φth are visualized using colored three-dimensional graphical representations; intensities are up to (1.97±0.13)×10 5 and (1.46±0.13)×10 4 n cm -2/Gy-X at isocenter, respectively. The Φth is found to increase with the X-ray energy of the LINAC and decreases as it moves away from the beam center. However, thermal neutron exposure is not assessed in routine dosimetry planning and radiation assessment of patients since neutron dose contributes <1% of the given therapy dose. However, unlike the accelerated beam limited within the gantry window, photoneutrons are widely spread in the treatment room. Distributions of Φth were measured in water phantom irradiated with 15 MV X-ray beams. The shielding effect of the maze was also evaluated. The experimentally estimated Φth along the maze distance was fitted explicate and the tenth-value layer (TVL) was calculated and discussed. Use of a 10 cm-thick polyethylene door placed at the maze was suitable for radiation shielding.

  13. Evidence for Accelerated Radioactive Decay (ARD) Models of Type I Supernova Lightcurves in the Low Redshift Universe

    NASA Astrophysics Data System (ADS)

    Rust, Bert W.; Leventhal, Marvin

    2014-06-01

    Forty years ago Van Hise [ApJ 192 (1974) 657-659] observed that the post peak light curve for the Type I supernova SN1937C is well represented by a sum of two exponentials with half lives which are ~ 0.75 of the terrestrial half lives of 56Ni and 56Co in the beta decay chain 56Ni → 56Co → 56Fe. Thirty nine years ago Leventhal and McCall [Nature 255 (1975) 690-692] proposed a fully convective, radioactive white dwarf model to account for the observed accelerated decay. Thirty eight years ago ARD models were tested by Rust, et al. [Nature 262 (1976) 118-120] on the data from the 15 fragmentary light curves available at that time. The results offered significant but not overwhelming support for ARD models. In this paper we present a new mathematical model for Type I lightcurves and fit that model, using only 6 free parameters, to an extensive collection of higher quality lightcurves that have been measured over the last 38 years. The fits all capture more than 99% of the total variance in the measured data, thus establishing the reality of an ARD lightcurve model. These new results provide a much improved Phillips relation for calibrating the extragalactic distance scale and testing other cosmological relations.

  14. Linear Accelerators

    SciTech Connect

    Sidorin, Anatoly

    2010-01-05

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  15. Small silencing RNAs: an expanding universe.

    PubMed

    Ghildiyal, Megha; Zamore, Phillip D

    2009-02-01

    Since the discovery in 1993 of the first small silencing RNA, a dizzying number of small RNA classes have been identified, including microRNAs (miRNAs), small interfering RNAs (siRNAs) and Piwi-interacting RNAs (piRNAs). These classes differ in their biogenesis, their modes of target regulation and in the biological pathways they regulate. There is a growing realization that, despite their differences, these distinct small RNA pathways are interconnected, and that small RNA pathways compete and collaborate as they regulate genes and protect the genome from external and internal threats.

  16. Research resources for Drosophila: the expanding universe.

    PubMed

    Matthews, Kathleen A; Kaufman, Thomas C; Gelbart, William M

    2005-03-01

    Drosophila melanogaster has been the subject of research into central questions about biological mechanisms for almost a century. The experimental tools and resources that are available or under development for D. melanogaster and its related species, particularly those for genomic analysis, are truly outstanding. Here we review three types of resource that have been developed for D. melanogaster research: databases and other sources of information, biological materials and experimental services. These resources are there to be exploited and we hope that this guide will encourage new uses for D. melanogaster information, materials and services, both by those new to flies and by experienced D. melanogaster researchers.

  17. The expanding universe of alkaloid biosynthesis.

    PubMed

    De Luca, V; Laflamme, P

    2001-06-01

    Characterization of many of the major gene families responsible for the generation of central intermediates and for their decoration, together with the development of large genomics and proteomics databases, has revolutionized our capability to identify exotic and interesting natural-product pathways. Over the next few years, these tools will facilitate dramatic advances in our knowledge of the biosynthesis of alkaloids, which will far surpass that which we have learned in the past 50 years. These tools will also be exploited for the rapid characterization of regulatory genes, which control the development of specialized cell factories for alkaloid biosynthesis.

  18. An expanding universe of noncoding RNAs.

    PubMed

    Storz, Gisela

    2002-05-17

    Noncoding RNAs (ncRNAs) have been found to have roles in a great variety of processes, including transcriptional regulation, chromosome replication, RNA processing and modification, messenger RNA stability and translation, and even protein degradation and translocation. Recent studies indicate that ncRNAs are far more abundant and important than initially imagined. These findings raise several fundamental questions: How many ncRNAs are encoded by a genome? Given the absence of a diagnostic open reading frame, how can these genes be identified? How can all the functions of ncRNAs be elucidated?

  19. An expanding universe of small proteins.

    PubMed

    Hobbs, Errett C; Fontaine, Fanette; Yin, Xuefeng; Storz, Gisela

    2011-04-01

    Historically, small proteins (sproteins) of less than 50 amino acids, in their final processed forms or genetically encoded as such, have been understudied. However, both serendipity and more recent focused efforts have led to the identification of a number of new sproteins in both Gram-negative and Gram-positive bacteria. Increasing evidence demonstrates that sproteins participate in a wide array of cellular processes and exhibit great diversity in their mechanisms of action, yet general principles of sprotein function are emerging. This review highlights examples of sproteins that participate in cell signaling, act as antibiotics and toxins, and serve as structural proteins. We also describe roles for sproteins in detecting and altering membrane features, acting as chaperones, and regulating the functions of larger proteins.

  20. Endothelial-regenerating cells: an expanding universe.

    PubMed

    Steinmetz, Martin; Nickenig, Georg; Werner, Nikos

    2010-03-01

    Atherosclerosis is the most common cause for cardiovascular diseases and is based on endothelial dysfunction. A growing body of evidence suggests the contribution of bone marrow-derived endothelial progenitor cells, monocytic cells, and mature endothelial cells to vessel formation and endothelial rejuvenation. To this day, various subsets of these endothelial-regenerating cells have been identified according to cellular origin, phenotype, and properties in vivo and in vitro. However, the definition and biology, especially of endothelial progenitor cells, is complex and under heavy debate. In this review, we focus on current definitions of endothelial progenitor cells, highlight the clinical relevance of endothelial-regenerating cells, and provide new insights into cell-cell interactions involved in endothelial cell rejuvenation.

  1. An expanding universe of small proteins

    PubMed Central

    Hobbs, Errett C.; Fontaine, Fanette; Yin, Xuefeng; Storz, Gisela

    2011-01-01

    Historically, small proteins of less than 50 amino acids, in their final processed forms or genetically encoded as such, have been understudied. However, both serendipity and more recent focused efforts have led to the identification of a number of new small proteins in both Gram-negative and Gram-positive bacteria. Increasing evidence demonstrates that small proteins participate in a wide array of cellular processes and exhibit great diversity in their mechanisms of action, yet general principles of small protein function are emerging. This review highlights examples of small proteins that participate in cell signaling, act as antibiotics and toxins, and serve as structural proteins. We also describe additional roles for small proteins in altering membrane fluidity, acting as metal chaperones, and regulating the functions of larger proteins. PMID:21342783

  2. Design and simulation of 3½-cell superconducting gun cavity and beam dynamics studies of the SASE-FEL System at the Institute of Accelerator Technologies at Ankara University

    NASA Astrophysics Data System (ADS)

    Yildiz, H. Duran; Cakir, R.; Porsuk, D.

    2015-06-01

    Design and simulation of a superconducting gun cavity with 3½ cells have been studied in order to give the first push to the electron beam for the linear accelerating system at The Institute of Accelerator Technologies at Ankara University. Electrons are accelerated through the gun cavity with the help of the Radiofrequency power suppliers from cryogenic systems. Accelerating gradient should be as high as possible to accelerate electron beam inside the cavity. In this study, electron beam reaches to 9.17 MeV energy at the end of the gun cavity with the accelerating gradient; Ec=19.21 MV/m. 1.3 GHz gun cavity consists of three TESLA-like shaped cells while the special designed gun-cell includes a cathode plug. Optimized important beam parameters inside the gun cavity, average beam current 3 mA, transverse emittance 2.5 mm mrad, repetition rate 30 MHz and other parameters are obtained for the SASE-FEL System. The Superfish/Poisson program is used to design each cell of the superconducting cavity. Superconducting gun cavity and Radiofrequency properties are studied by utilizing 2D Superfish/Poisson, 3D Computer Simulation Technology Microwave Studio, and 3D Computer Simulation Technology Particle Studio. Superfish/Poisson is also used to optimize the geometry of the cavity cells to get the highest accelerating gradient. The behavior of the particles along the beamline is included in this study. ASTRA Code is used to track the particles.

  3. Universal Usability

    NASA Astrophysics Data System (ADS)

    Horton, Sarah; Leventhal, Laura

    Universal usability of World Wide Web (Web) environments—that is, having 90% of households as successful users—requires universal access, usability, and universal design. Factors such as Web technology and user-centered design contribute to universal access and usability, but key to universal usability is a universal design methodology. Universal design principles for the Web follow from universal design principles for the built environment, and emphasize perceptibility, self-explanation, and tailorability for the user. Universally usable Web environments offer the benefit of expanded participation, as well as the unanticipated benefits that generally follow from innovative design initiatives. However, to achieve Web universal usability, Web designers need tools that facilitate the design of intuitive interfaces without sacrificing universal access.

  4. Preliminary energy-filtering neutron imaging with time-of-flight method on PKUNIFTY: A compact accelerator based neutron imaging facility at Peking University

    NASA Astrophysics Data System (ADS)

    Wang, Hu; Zou, Yubin; Wen, Weiwei; Lu, Yuanrong; Guo, Zhiyu

    2016-07-01

    Peking University Neutron Imaging Facility (PKUNIFTY) works on an accelerator-based neutron source with a repetition period of 10 ms and pulse duration of 0.4 ms, which has a rather low Cd ratio. To improve the effective Cd ratio and thus improve the detection capability of the facility, energy-filtering neutron imaging was realized with the intensified CCD camera and time-of-flight (TOF) method. Time structure of the pulsed neutron source was firstly simulated with Geant4, and the simulation result was evaluated with experiment. Both simulation and experiment results indicated that fast neutrons and epithermal neutrons were concentrated in the first 0.8 ms of each pulse period; meanwhile in the period of 0.8-2.0 ms only thermal neutrons existed. Based on this result, neutron images with and without energy filtering were acquired respectively, and it showed that detection capability of PKUNIFTY was improved with setting the exposure interval as 0.8-2.0 ms, especially for materials with strong moderating capability.

  5. The Black Hole Universe Model

    NASA Astrophysics Data System (ADS)

    Zhang, Tianxi

    2014-06-01

    The black hole universe model is a multiverse model of cosmology recently developed by the speaker. According to this new model, our universe is a fully grown extremely supermassive black hole, which originated from a hot star-like black hole with several solar masses, and gradually grew up from a supermassive black hole with million to billion solar masses to the present state with trillion-trillion solar masses by accreting ambient matter or merging with other black holes. The entire space is structured with infinite layers or universes hierarchically. The innermost three layers include the universe that we live, the inside star-like and supermassive black holes called child universes, and the outside space called mother universe. The outermost layer is infinite in mass, radius, and entropy without an edge and limits to zero for both the matter density and absolute temperature. All layers are governed by the same physics and tend to expand physically in one direction (outward or the direction of increasing entropy). The expansion of a black hole universe decreases its density and temperature but does not alter the laws of physics. The black hole universe evolves iteratively and endlessly without a beginning. When one universe expands out, a new similar one is formed from inside star-like and supermassive black holes. In each of iterations, elements are resynthesized, matter is reconfigurated, and the universe is renewed rather than a simple repeat. The black hole universe is consistent with the Mach principle, observations, and Einsteinian general relativity. It has only one postulate but is able to explain all phenomena occurred in the universe with well-developed physics. The black hole universe does not need dark energy for acceleration and an inflation epoch for flatness, and thus has a devastating impact on the big bang model. In this talk, I will present how this new cosmological model explains the various aspects of the universe, including the origin

  6. Functionalized expanded porphyrins

    DOEpatents

    Sessler, Jonathan L; Pantos, Patricia J

    2013-11-12

    Disclosed are functionalized expanded porphyrins that can be used as spectrometric sensors for high-valent actinide cations. The disclosed functionalized expanded porphyrins have the advantage over unfunctionalized systems in that they can be immobilized via covalent attachment to a solid support comprising an inorganic or organic polymer or other common substrates. Substrates comprising the disclosed functionalized expanded porphyrins are also disclosed. Further, disclosed are methods of making the disclosed compounds (immobilized and free), methods of using them as sensors to detect high valent actinides, devices that comprise the disclosed compounds, and kits.

  7. Acceleration in astrophysics

    SciTech Connect

    Colgate, S.A.

    1993-12-31

    The origin of cosmic rays and applicable laboratory experiments are discussed. Some of the problems of shock acceleration for the production of cosmic rays are discussed in the context of astrophysical conditions. These are: The presumed unique explanation of the power law spectrum is shown instead to be a universal property of all lossy accelerators; the extraordinary isotropy of cosmic rays and the limited diffusion distances implied by supernova induced shock acceleration requires a more frequent and space-filling source than supernovae; the near perfect adiabaticity of strong hydromagnetic turbulence necessary for reflecting the accelerated particles each doubling in energy roughly 10{sup 5} to {sup 6} scatterings with negligible energy loss seems most unlikely; the evidence for acceleration due to quasi-parallel heliosphere shocks is weak. There is small evidence for the expected strong hydromagnetic turbulence, and instead, only a small number of particles accelerate after only a few shock traversals; the acceleration of electrons in the same collisionless shock that accelerates ions is difficult to reconcile with the theoretical picture of strong hydromagnetic turbulence that reflects the ions. The hydromagnetic turbulence will appear adiabatic to the electrons at their much higher Larmor frequency and so the electrons should not be scattered incoherently as they must be for acceleration. Therefore the electrons must be accelerated by a different mechanism. This is unsatisfactory, because wherever electrons are accelerated these sites, observed in radio emission, may accelerate ions more favorably. The acceleration is coherent provided the reconnection is coherent, in which case the total flux, as for example of collimated radio sources, predicts single charge accelerated energies much greater than observed.

  8. Cholesterol accelerates the binding of Alzheimer's β-amyloid peptide to ganglioside GM1 through a universal hydrogen-bond-dependent sterol tuning of glycolipid conformation

    PubMed Central

    Fantini, Jacques; Yahi, Nouara; Garmy, Nicolas

    2013-01-01

    Age-related alterations of membrane lipids in brain cell membranes together with high blood cholesterol are considered as major risk factors for Alzheimer's disease. Yet the molecular mechanisms by which these factors increase Alzheimer's risk are mostly unknown. In lipid raft domains of the plasma membrane, neurotoxic Alzheimer's beta-amyloid (Abeta) peptides interact with both cholesterol and ganglioside GM1. Recent data also suggested that cholesterol could stimulate the binding of Abeta to GM1 through conformational modulation of the ganglioside headgroup. Here we used a combination of physicochemical and molecular modeling approaches to decipher the mechanisms of cholesterol-assisted binding of Abeta to GM1. With the aim of decoupling the effect of cholesterol on GM1 from direct Abeta-cholesterol interactions, we designed a minimal peptide (Abeta5-16) containing the GM1-binding domain but lacking the amino acid residues involved in cholesterol recognition. Using the Langmuir technique, we showed that cholesterol (but not phosphatidylcholine or sphingomyelin) significantly accelerates the interaction of Abeta5-16 with GM1. Molecular dynamics simulations suggested that Abeta5-16 interacts with a cholesterol-stabilized dimer of GM1. The main structural effect of cholesterol is to establish a hydrogen-bond between its own OH group and the glycosidic-bond linking ceramide to the glycone part of GM1, thereby inducing a tilt in the glycolipid headgroup. This fine conformational tuning stabilizes the active conformation of the GM1 dimer whose headgroups, oriented in two opposite directions, form a chalice-shaped receptacle for Abeta. These data give new mechanistic insights into the stimulatory effect of cholesterol on Abeta/GM1 interactions. They also support the emerging concept that cholesterol is a universal modulator of protein-glycolipid interactions in the broader context of membrane recognition processes. PMID:23772214

  9. The Beginning and End of the Universe

    NASA Technical Reports Server (NTRS)

    Gardner, Jonathan P.

    2007-01-01

    Cosmology is the scientific study of how the Universe began more than 13 billion years ago, how its properties have changed, and what its future might be. The balance of forces and energy cause the Universe to expand, first accelerating, then decelerating and then accelerating again. Within this overall structure, the interplay of atoms and light with the mysterious dark matter and dark energy causes stars and galaxies to form and evolve, leading to galaxies like our own home, the Milky Way. Observational cosmology uses telescopes on Earth and in space to reach back in time to find the faint remaining echoes of the Big Bang and to trace the formation and evolution of the galaxies and structures that fill the Universe. In this lecture, Dr. Gardner will give an overview of cosmology, outlining the 13-billion year history of the Universe, and highlighting the very rapid progress this field has made in the last decade. He will discuss the role that NASA space telescopes have played in this progress and will continue to play in the years to come. He will give a time-based history of the Universe, discussing the successive processes that formed matter, particles, atoms, stars and galaxies. In particular, he will focus on cosmological inflation, the rapid accelerated expansion that marks the beginning of the Universe, and dark energy, a tenuous substance that overcomes gravity and whose properties will determine its final fate.

  10. The Beginning and End of the Universe

    NASA Technical Reports Server (NTRS)

    Gardner, Jonathan

    2008-01-01

    Cosmology is the scientific study of how the Universe began more than 13 billion years ago, how its properties have changed, and what its future might be. The balance of forces and energy cause the Universe to expand, first accelerating, then decelerating and then accelerating again. Within this overall structure, the interplay of atoms and light with the mysterious dark matter and dark energy causes stars and galaxies to form and evolve, leading to galaxies like our own home, the Milky Way. Observational cosmology uses telescopes on Earth and in space to reach back in time to find the faint remaining echoes of the Big Bang and to trace the formation and evolution of the galaxies and structures that fill the Universe. In this lecture, Dr. Gradner will give an overview of cosmology, outlining the 13-billion year history of the Universe, and highlighting the very rapid progress this field has made i the last decade. He will discuss the role that NASA space telescopes have played in this progress and wil continue to play in the years to come. He will give a time-based history of the Universe, discussing the successive processes that formed matter, particles, atoms, stars and galaxies. In particular, he will focus on cosmological inflation, the rapid accelerated expansion that marks the beginning of the Universe, and dark energy, a tenuous substance that overcomes gravity and whose properties will determine its final fate.

  11. Wake field acceleration experiments

    SciTech Connect

    Simpson, J.D.

    1988-01-01

    Where and how will wake field acceleration devices find use for other than, possibly, accelerators for high energy physics. I don't know that this can be responsibly answered at this time. What I can do is describe some recent results from an ongoing experimental program at Argonne which support the idea that wake field techniques and devices are potentially important for future accelerators. Perhaps this will spawn expanded interest and even new ideas for the use of this new technology. The Argonne program, and in particular the Advanced Accelerator Test Facility (AATF), has been reported in several fairly recent papers and reports. But because this is a substantially new audience for the subject, I will include a brief review of the program and the facility before describing experiments. 10 refs., 7 figs.

  12. Theme: The Expanded Mission.

    ERIC Educational Resources Information Center

    Finley, Eddy; And Others

    1991-01-01

    This theme issue covers the following topics: modernization of agricultural education, an expanded mission for the field, community development, a national presence for agricultural education, revising curriculum, and interesting students in new careers in agriculture. (SK)

  13. Optimization of expander plants

    SciTech Connect

    Wang, W.B.

    1985-01-01

    A computer program that uses the Tomich technique to solve multistage, multi-feed distillation problems was modified. The MSEQ method was utilized to generate initial temperature and vapor rate profiles. The modified fractionator program coupled with the MSEQ method was used to generate required rigorous data for expander-plant demethanizer splits. Furthermore, a shortcut method was developed to facilitate expander process simulation. Calculated demethanizer results from a simulation were compared with a commercial program with good agreement. The results from the shortcut method were in good agreement with rigorous calculations. Computer simulations were made for four different natural gases ranging from lean to rich in liquefiable hydrocarbons for various turboexpander plant processes. These processes included self-refrigerated expander process with/without external refrigeration, and with/without demethanizer heat recovery. Only lean gases can be utilized in the self-refrigerated expander process with high ethane recovery. While the use of external refrigeration in conjunction with the expander process can reduce overall horsepower requirements, it may not be economical to do so. In general, the processing should be carried out at the highest practical processing pressure. The use of demethanizer heat recovery is an efficient method to reduce both refrigeration horsepower and recompression energy requirements. This work emphasizes high ethane recovery. Further study of expander processes emphasizing ethane rejection is advisable.

  14. Expanding the Canon

    ERIC Educational Resources Information Center

    Villano, Matt

    2009-01-01

    Original research and content creation in the university environment have historically been the domain of faculty and their graduate students. Nowadays, however, undergraduate programs at universities across the country are putting undergrads in the center of the action. This article describes some of these programs--at Duke University (North…

  15. Topics in Cosmic Acceleration and Braneworlds

    NASA Astrophysics Data System (ADS)

    West, Eric J.

    Cosmic acceleration has come to be a standard, and perhaps required, ingredient in our current understanding of the universe. In the early universe, under the name of inflation, a phase of accelerated expansion is used to solve many problems with the standard Hot Big Bang cosmology. In the late universe, cosmic acceleration seems to best explain a wide variety of observations. In both cases, we lack a complete theory of what drives cosmic acceleration. In this thesis I discuss some open issues in our understanding of cosmic acceleration, both in the early and late universe.

  16. Expanding Assessment Methods and Moments in History

    ERIC Educational Resources Information Center

    Frost, Jennifer; de Pont, Genevieve; Brailsford, Ian

    2012-01-01

    History courses at The University of Auckland are typically assessed at two or three moments during a semester. The methods used normally employ two essays and a written examination answering questions set by the lecturer. This study describes an assessment innovation in 2008 that expanded both the frequency and variety of activities completed by…

  17. Expanded Subject Access to Reference Collection Materials.

    ERIC Educational Resources Information Center

    Mischo, William H.

    1979-01-01

    Reports a computer assisted index emphasizing expanded subject access to the reference collection of the Iowa State University Library. The index displays abbreviated length records and complements existing catalogs. Limitations of subject access and a system for assigning subject descriptors are discussed. (Author/RAA)

  18. Silicon microfabricated beam expander

    SciTech Connect

    Othman, A. Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-03-30

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  19. Expander plant design

    SciTech Connect

    Not Available

    1986-01-01

    Expander plant design is iterative. In order to calculate an answer it is necessary to have an answer to start with. Consequently, the starting point for a final design is a function of the experience level of the designer and his personal preference. This paper assumes that the designer has no experience in expander plant design and concentrates on providing methods for assuming an answer that will be close enough to the final answer that the design can be done with a minimum number of iterations. For illustration, several typical process designs are presented.

  20. Expanding Student Assessment Opportunities.

    ERIC Educational Resources Information Center

    Bartscher, Beth; Carter, Andrea; Lawlor, Anna; McKelvey, Barbara

    This paper describes an approach for expanding assessment opportunities for students to demonstrate their understanding of content. The targeted population consisted of elementary and junior high school students in two schools in a growing middle-class community in north central Illinois. The elementary school enrolled 467 students and the junior…

  1. Expanded Roles for HRD.

    ERIC Educational Resources Information Center

    1998

    This document contains three papers from a symposium on expanded roles for human resource development (HRD). "The Roles of Consultants in Gainsharing Firms: Empirical Results" (Eunsang Cho, Gary N. McLean) reports findings that consultants are moderately involved at the separation, preparation, evaluation, and design stages and have low…

  2. Future accelerators (?)

    SciTech Connect

    John Womersley

    2003-08-21

    I describe the future accelerator facilities that are currently foreseen for electroweak scale physics, neutrino physics, and nuclear structure. I will explore the physics justification for these machines, and suggest how the case for future accelerators can be made.

  3. ExpandED Options: Learning beyond High School Walls

    ERIC Educational Resources Information Center

    ExpandED Schools, 2014

    2014-01-01

    Through ExpandED Options by TASC, New York City high school students get academic credit for learning career-related skills that lead to paid summer jobs. Too many high school students--including those most likely to drop out--are bored or see classroom learning as irrelevant. ExpandED Options students live the connection between mastering new…

  4. A direct probe of the evolutionary history of the primordial universe

    NASA Astrophysics Data System (ADS)

    Chen, Xingang; Namjoo, Mohammad Hossein; Wang, Yi

    2016-10-01

    Since Hubble and Lamaitre's discovery of the expanding universe using galaxies till the recent discovery of the accelerating universe using standard candles, direct measurements of the evolution of the scale factor of the universe a(t) have played central roles in establishing the standard model of cosmology. In this letter, we show that such a measurement may be extended to the primordial universe using massive fields as standard clocks, providing a direct evidence for the scenario responsible for the Big Bang. This is a short and non-technical introduction to the idea of classical and quantum primordial standard clocks.

  5. Expanding your horizons in science and mathematics

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Through the presentation of its Expanding Your Horizons in Science and Mathematics career education conferences for secondary school young women, the Math/Science Network continues its efforts to remove the educational, psychological, and cultural barriers which prevent women from entering math-and science-based careers. The Expanding Your Horizons conferences were presented on 77 college, university and high school campuses across the United States. This year, these unique one day conferences reached 15,500 students, 3,000 parents and educators, and involved 3,000 career women who volunteered their services as conference planners, workshop leaders, speakers, and role models.

  6. Expandable LED array interconnect

    DOEpatents

    Yuan, Thomas Cheng-Hsin; Keller, Bernd

    2011-03-01

    A light emitting device that can function as an array element in an expandable array of such devices. The light emitting device comprises a substrate that has a top surface and a plurality of edges. Input and output terminals are mounted to the top surface of the substrate. Both terminals comprise a plurality of contact pads disposed proximate to the edges of the substrate, allowing for easy access to both terminals from multiple edges of the substrate. A lighting element is mounted to the top surface of the substrate. The lighting element is connected between the input and output terminals. The contact pads provide multiple access points to the terminals which allow for greater flexibility in design when the devices are used as array elements in an expandable array.

  7. Grazing incidence beam expander

    SciTech Connect

    Akkapeddi, P.R.; Glenn, P.; Fuschetto, A.; Appert, Q.; Viswanathan, V.K.

    1985-01-01

    A Grazing Incidence Beam Expander (GIBE) telescope is being designed and fabricated to be used as an equivalent end mirror in a long laser resonator cavity. The design requirements for this GIBE flow down from a generic Free Electron Laser (FEL) resonator. The nature of the FEL gain volume (a thin, pencil-like, on-axis region) dictates that the output beam be very small. Such a thin beam with the high power levels characteristic of FELs would have to travel perhaps hundreds of meters or more before expanding enough to allow reflection from cooled mirrors. A GIBE, on the other hand, would allow placing these optics closer to the gain region and thus reduces the cavity lengths substantially. Results are presented relating to optical and mechanical design, alignment sensitivity analysis, radius of curvature analysis, laser cavity stability analysis of a linear stable concentric laser cavity with a GIBE. Fabrication details of the GIBE are also given.

  8. Radiation from violently accelerated bodies

    NASA Astrophysics Data System (ADS)

    Gerlach, Ulrich H.

    2001-11-01

    A determination is made of the radiation emitted by a linearly uniformly accelerated uncharged dipole transmitter. It is found that, first of all, the radiation rate is given by the familiar Larmor formula, but it is augmented by an amount which becomes dominant for sufficiently high acceleration. For an accelerated dipole oscillator, the criterion is that the center of mass motion become relativistic within one oscillation period. The augmented formula and the measurements which it summarizes presuppose an expanding inertial observation frame. A static inertial reference frame will not do. Secondly, it is found that the radiation measured in the expanding inertial frame is received with 100% fidelity. There is no blueshift or redshift due to the accelerative motion of the transmitter. Finally, it is found that a pair of coherently radiating oscillators accelerating (into opposite directions) in their respective causally disjoint Rindler-coordinatized sectors produces an interference pattern in the expanding inertial frame. Like the pattern of a Young double slit interferometer, this Rindler interferometer pattern has a fringe spacing which is inversely proportional to the proper separation and the proper frequency of the accelerated sources. The interferometer, as well as the augmented Larmor formula, provide a unifying perspective. It joins adjacent Rindler-coordinatized neighborhoods into a single spacetime arena for scattering and radiation from accelerated bodies.

  9. A transition from a decelerated to an accelerated phase of the universe expansion from the simplest non-trivial polynomial function of T in the f(R,T) formalism

    NASA Astrophysics Data System (ADS)

    Moraes, P. H. R. S.; Ribeiro, G.; Correa, R. A. C.

    2016-07-01

    In this work we present cosmological solutions from the simplest non-trivial polynomial function of T in f(R,T) theory of gravity, with R and T standing for the Ricci scalar and trace of the energy-momentum tensor, respectively. Although such an approach yields a highly non-linear differential equation for the scale factor, we show that it is possible to obtain analytical solutions for the cosmological parameters. For some values of the free parameters, the model is able to predict a transition from a decelerated to an accelerated expansion of the universe and the values of the deceleration parameter agree with observation.

  10. UPDATE HANFORD SITE D & D PROGRAMS ACCELERATE EXPAND

    SciTech Connect

    GERBER, M.S.

    2004-04-22

    A large, new decontamination and decommissioning organization targeted toward rapid, focused work on aging and highly contaminated structures was formed at the DOE's Hanford Site in southeast Washington state in autumn 2003. Managed by prime contractor Fluor Hanford, the new organization has made significant progress during its first six months. Under the direction of Mike Lackey, who recently joined Fluor from the Portland General Electric Trojan Plant, the Fluor Hanford D&D organization is tackling the Plutonium Finishing Plant (PFP) complex and the Fast Flux Test Facility (FFTF), and is nearly finished demolishing the 233-S Plutonium Concentration Facility. In addition, the D&D organization is progressing through the development and public comment phases of its required environmental permitting, planning work and procurement services to D&D three other Hanford facilities: 224-T and 224-B Plutonium Concentration Facilities, and the U Plant radiochemical processing facility. It is also planning and beginning to D&D the spent fuel handling areas of the Site's 100-K Reactor Area. The 586-square mile Hanford Site, the oldest plutonium production center in the world, served as the ''workhorse'' of the American nuclear defense arsenal from 1944 through 1989. Hanford produced the special nuclear material for the plutonium cores of the Trinity (test) and Nagasaki explosions, and then went on to produce more than half of the weapons plutonium ever manufactured by the United States, and about one-fourth of that manufactured worldwide. As a result, Hanford, the top-secret ''Paul Bunyan'' in the desert, is one of the most contaminated areas in the world. Its cleanup agreement with state and federal regulators, known as the ''Tri-Party Agreement,'' celebrates its 15th anniversary this spring, at a time when operations dealing with unstable plutonium leftovers, corroded spent fuel, and liquids wastes in single-shelled tanks conclude. As these crucial jobs are coming to an end, D&D has gained traction as a central Site mission.

  11. Expanded criteria donors.

    PubMed

    Feng, Sandy; Lai, Jennifer C

    2014-08-01

    The greatest challenge facing liver transplantation today is the shortage of donor livers. Demand far exceeds supply, and this deficit has driven expansion of what is considered an acceptable organ. The evolving standard has not come without costs, however, as each new frontier of expanded donor quality (i.e., advancing donor age, donation after cardiac death, and split liver) may have traded wait-list for post-transplant morbidity and mortality. This article delineates the nature and severity of risk associated with specific deceased donor liver characteristics and recommends strategies to maximally mitigate these risks. PMID:25017080

  12. Undulant Universe

    SciTech Connect

    Barenboim, Gabriela; Mena, Olga; Quigg, Chris; /Fermilab

    2004-12-01

    If the equation of state for ''dark energy'' varies periodically, the expansion of the Universe may have undergone alternating eras of acceleration and deceleration. We examine a specific form that survives existing observational tests, does not single out the present state of the Universe as exceptional, and suggests a future much like the matter-dominated past: a smooth expansion without a final inflationary epoch.

  13. Expanding the Trilinos developer community.

    SciTech Connect

    Heroux, Michael Allen

    2010-10-01

    The Trilinos Project started approximately nine years ago as a small effort to enable research, development and ongoing support of small, related solver software efforts. The 'Tri' in Trilinos was intended to indicate the eventual three packages we planned to develop. In 2007 the project expanded its scope to include any package that was an enabling technology for technical computing. Presently the Trilinos repository contains over 55 packages covering a broad spectrum of reusable tools for constructing full-featured scalable scientific and engineering applications. Trilinos usage is now worldwide, and many applications have an explicit dependence on Trilinos for essential capabilities. Users come from other US laboratories, universities, industry and international research groups. Awareness and use of Trilinos is growing rapidly outside of Sandia. Members of the external research community are becoming more familiar with Trilinos, its design and collaborative nature. As a result, the Trilinos project is receiving an increasing number of requests from external community members who want to contribute to Trilinos as developers. To-date we have worked with external developers in an ad hoc fashion. Going forward, we want to develop a set of policies, procedures, tools and infrastructure to simplify interactions with external developers. As we go forward with multi-laboratory efforts such as CASL and X-Stack, and international projects such as IESP, we will need a more streamlined and explicit process for making external developers 'first-class citizens' in the Trilinos development community. This document is intended to frame the discussion for expanding the Trilinos community to all strategically important external members, while at the same time preserving Sandia's primary leadership role in the project.

  14. Emergence of oscillons in an expanding background

    SciTech Connect

    Farhi, E.; Guth, A. H.; Iqbal, N.; Graham, N.; Rosales, R. R.; Stamatopoulos, N.

    2008-04-15

    We consider a (1+1) dimensional scalar field theory that supports oscillons, which are localized, oscillatory, stable solutions to nonlinear equations of motion. We study this theory in an expanding background and show that oscillons now lose energy, but at a rate that is exponentially small when the expansion rate is slow. We also show numerically that a universe that starts with (almost) thermal initial conditions will cool to a final state where a significant fraction of the energy of the universe--on the order of 50%--is stored in oscillons. If this phenomenon persists in realistic models, oscillons may have cosmological consequences.

  15. Large classical universes emerging from quantum cosmology

    SciTech Connect

    Pinto-Neto, Nelson

    2009-04-15

    It is generally believed that one cannot obtain a large universe from quantum cosmological models without an inflationary phase in the classical expanding era because the typical size of the universe after leaving the quantum regime should be around the Planck length, and the standard decelerated classical expansion after that is not sufficient to enlarge the universe in the time available. For instance, in many quantum minisuperspace bouncing models studied in the literature, solutions where the universe leaves the quantum regime in the expanding phase with appropriate size have negligible probability amplitude with respect to solutions leaving this regime around the Planck length. In this paper, I present a general class of moving Gaussian solutions of the Wheeler-DeWitt equation where the velocity of the wave in minisuperspace along the scale factor axis, which is the new large parameter introduced in order to circumvent the above-mentioned problem, induces a large acceleration around the quantum bounce, forcing the universe to leave the quantum regime sufficiently big to increase afterwards to the present size, without needing any classical inflationary phase in between, and with reasonable relative probability amplitudes with respect to models leaving the quantum regime around the Planck scale. Furthermore, linear perturbations around this background model are free of any trans-Planckian problem.

  16. Expanding Sports Facilities.

    ERIC Educational Resources Information Center

    Koger, Dale

    2001-01-01

    Explains how colleges and universities can increase revenue and enhance status by upgrading their stadiums and arenas. Related issues considered are: determining how much a school should add to its existing stadium and arena, selecting the design and management team, and raising capital. Outlines key areas that design and construction teams should…

  17. Expanding the Conversation

    ERIC Educational Resources Information Center

    Branch-Brioso, Karen

    2009-01-01

    They are not the topics found in a conventional law review: An Austin-based journal delved into the reproductive rights of Hispanic women entering into commercial surrogacy contracts. The next issue of a University of California, Berkeley-based journal will probe the Voting Rights Act--and how it affects Puerto Ricans. A Harvard-based review once…

  18. Expandable pattern casting research

    NASA Astrophysics Data System (ADS)

    1993-09-01

    The Expandable Pattern Casting (EPC) Process is a developing foundry technology that allows designers the opportunity to consolidate parts, reduce machining, and minimize assembly operations. An air gauging system was developed for measuring foam patterns; exact shrinkage depended on type and density of the foam. Compaction studies showed that maximum sand densities in cavities and under overhangs are achieved with vibrational amplitudes 0.001-0.004 in., and that sand moved most freely within a few inches of the top free surface. Key to complete mold filling while minimizing casting defects lies in removing the foam decomposition products. The most precise iron castings were made by EPC in four commercial EPC foundries, with attention paid to molding and compaction. EP cast 60-45-12 ductile iron had yield strengths, ultimate strengths, and elastic modulus similar to conventionally cast ductile iron cast from the same ladle.

  19. Expanding hollow metal rings

    DOEpatents

    Peacock, Harold B.; Imrich, Kenneth J.

    2009-03-17

    A sealing device that may expand more planar dimensions due to internal thermal expansion of a filler material. The sealing material is of a composition such that when desired environment temperatures and internal actuating pressures are reached, the sealing materials undergoes a permanent deformation. For metallic compounds, this permanent deformation occurs when the material enters the plastic deformation phase. Polymers, and other materials, may be using a sealing mechanism depending on the temperatures and corrosivity of the use. Internal pressures are generated by either rapid thermal expansion or material phase change and may include either liquid or solid to gas phase change, or in the gaseous state with significant pressure generation in accordance with the gas laws. Sealing material thickness and material composition may be used to selectively control geometric expansion of the seal such that expansion is limited to a specific facing and or geometric plane.

  20. Mechanically expandable annular seal

    DOEpatents

    Gilmore, Richard F.

    1983-01-01

    A mechanically expandable annular reusable seal assembly to form an annular hermetic barrier between two stationary, parallel, and planar containment surfaces. A rotatable ring, attached to the first surface, has ring wedges resembling the saw-tooth array of a hole saw. Matching seal wedges are slidably attached to the ring wedges and have their motion restricted to be perpendicular to the second surface. Each seal wedge has a face parallel to the second surface. An annular elastomer seal has a central annular region attached to the seal wedges' parallel faces and has its inner and outer circumferences attached to the first surface. A rotation of the ring extends the elastomer seal's central region perpendicularly towards the second surface to create the fluidtight barrier. A counterrotation removes the barrier.

  1. Mechanically expandable annular seal

    DOEpatents

    Gilmore, R.F.

    1983-07-19

    A mechanically expandable annular reusable seal assembly to form an annular hermetic barrier between two stationary, parallel, and planar containment surfaces is described. A rotatable ring, attached to the first surface, has ring wedges resembling the saw-tooth array of a hole saw. Matching seal wedges are slidably attached to the ring wedges and have their motion restricted to be perpendicular to the second surface. Each seal wedge has a face parallel to the second surface. An annular elastomer seal has a central annular region attached to the seal wedges' parallel faces and has its inner and outer circumferences attached to the first surface. A rotation of the ring extends the elastomer seal's central region perpendicularly towards the second surface to create the fluid tight barrier. A counter rotation removes the barrier. 6 figs.

  2. Biomedical accelerator mass spectrometry

    NASA Astrophysics Data System (ADS)

    Freeman, Stewart P. H. T.; Vogel, John S.

    1995-05-01

    Ultrasensitive SIMS with accelerator based spectrometers has recently begun to be applied to biomedical problems. Certain very long-lived radioisotopes of very low natural abundances can be used to trace metabolism at environmental dose levels ( [greater-or-equal, slanted] z mol in mg samples). 14C in particular can be employed to label a myriad of compounds. Competing technologies typically require super environmental doses that can perturb the system under investigation, followed by uncertain extrapolation to the low dose regime. 41Ca and 26Al are also used as elemental tracers. Given the sensitivity of the accelerator method, care must be taken to avoid contamination of the mass spectrometer and the apparatus employed in prior sample handling including chemical separation. This infant field comprises the efforts of a dozen accelerator laboratories. The Center for Accelerator Mass Spectrometry has been particularly active. In addition to collaborating with groups further afield, we are researching the kinematics and binding of genotoxins in-house, and we support innovative uses of our capability in the disciplines of chemistry, pharmacology, nutrition and physiology within the University of California. The field can be expected to grow further given the numerous potential applications and the efforts of several groups and companies to integrate more the accelerator technology into biomedical research programs; the development of miniaturized accelerator systems and ion sources capable of interfacing to conventional HPLC and GMC, etc. apparatus for complementary chemical analysis is anticipated for biomedical laboratories.

  3. Development of PUNDA (Parametric Universal Nonlinear Dynamics Approximator) Models for Self-Validating Knowledge-Guided Modelling of Nonlinear Processes in Particle Accelerators \\& Industry

    SciTech Connect

    Sayyar-Rodsari, Bijan; Schweiger, Carl; Hartman, Eric

    2007-10-07

    The difficult problems being tackled in the accelerator community are those that are nonlinear, substantially unmodeled, and vary over time. Such problems are ideal candidates for model-based optimization and control if representative models of the problem can be developed that capture the necessary mathematical relations and remain valid throughout the operation region of the system, and through variations in system dynamics. The goal of this proposal is to develop the methodology and the algorithms for building high-fidelity mathematical representations of complex nonlinear systems via constrained training of combined first-principles and neural network models.

  4. Introduction to Korean Accelerator Science and Activities in Industrial Accelerators

    NASA Astrophysics Data System (ADS)

    Namkung, Won

    2012-03-01

    After 20 years of the first large-scale accelerator in Korea, the Pohang Light Source (PLS) of 2.0 GeV at POSTECH, its upgrade (PLS-II) is now under commissioning with energy of 3.0 GeV. The users' service for synchrotron radiation is scheduled in April 2012. There are five big accelerator projects in various stages of construction, namely a high-intensity proton linac of 100 MeV, the PAL-XFEL of 10-GeV, a carbon therapy cyclotron of 400 MeV/u, and rare isotope accelerators for isotope separator on-line (ISOL) and In-flight Fragmentation (IFF). There are also strong demands for industrial uses of accelerators, especially in sterilization applications. In this paper, we report the current status of accelerator projects and its science in Korea, along with a brief review of accelerator R&D going back to the early 1960s at universities.

  5. Wakefield accelerators

    SciTech Connect

    Simpson, J.D.

    1990-01-01

    The search for new methods to accelerate particle beams to high energy using high gradients has resulted in a number of candidate schemes. One of these, wakefield acceleration, has been the subject of considerable R D in recent years. This effort has resulted in successful proof of principle experiments and in increased understanding of many of the practical aspects of the technique. Some wakefield basics plus the status of existing and proposed experimental work is discussed, along with speculations on the future of wake field acceleration. 10 refs., 6 figs.

  6. LINEAR ACCELERATOR

    DOEpatents

    Colgate, S.A.

    1958-05-27

    An improvement is presented in linear accelerators for charged particles with respect to the stable focusing of the particle beam. The improvement consists of providing a radial electric field transverse to the accelerating electric fields and angularly introducing the beam of particles in the field. The results of the foregoing is to achieve a beam which spirals about the axis of the acceleration path. The combination of the electric fields and angular motion of the particles cooperate to provide a stable and focused particle beam.

  7. Perturbations for transient acceleration

    SciTech Connect

    Vargas, Cristofher Zuñiga; Zimdahl, Winfried; Hipólito-Ricaldi, Wiliam S. E-mail: hipolito@ceunes.ufes.br

    2012-04-01

    According to the standard ΛCDM model, the accelerated expansion of the Universe will go on forever. Motivated by recent observational results, we explore the possibility of a finite phase of acceleration which asymptotically approaches another period of decelerated expansion. Extending an earlier study on a corresponding homogeneous and isotropic dynamics, in which interactions between dark matter and dark energy are crucial, the present paper also investigates the dynamics of the matter perturbations both on the Newtonian and General Relativistic (GR) levels and quantifies the potential relevance of perturbations of the dark-energy component. In the background, the model is tested against the Supernova type Ia (SNIa) data of the Constitution set and on the perturbative level against growth rate data, among them those of the WiggleZ survey, and the data of the 2dFGRS project. Our results indicate that a transient phase of accelerated expansion is not excluded by current observations.

  8. What Are the Appropriate Models for St. Petersburg College and the University Partnership Center To Expand Access to Bachelor's and Master's Degrees? Project Eagle Evaluation Question #5. Benchmarking St. Petersburg College: A Report to Leadership.

    ERIC Educational Resources Information Center

    Burkhart, Joyce

    St. Petersburg College (SPC) (Florida), formerly a two-year community college, now offers four-year degrees. This paper discusses the findings of SPC's evaluation question focusing on what the appropriate models are for St. Petersburg College and the University Partnership Center (UPC) to increase access to bachelor's and master's programs.…

  9. ION ACCELERATOR

    DOEpatents

    Bell, J.S.

    1959-09-15

    An arrangement for the drift tubes in a linear accelerator is described whereby each drift tube acts to shield the particles from the influence of the accelerating field and focuses the particles passing through the tube. In one embodiment the drift tube is splii longitudinally into quadrants supported along the axis of the accelerator by webs from a yoke, the quadrants. webs, and yoke being of magnetic material. A magnetic focusing action is produced by energizing a winding on each web to set up a magnetic field between adjacent quadrants. In the other embodiment the quadrants are electrically insulated from each other and have opposite polarity voltages on adjacent quadrants to provide an electric focusing fleld for the particles, with the quadrants spaced sufficienily close enough to shield the particles within the tube from the accelerating electric field.

  10. Acceleration switch

    DOEpatents

    Abbin, J.P. Jr.; Devaney, H.F.; Hake, L.W.

    1979-08-29

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  11. Acceleration switch

    DOEpatents

    Abbin, Jr., Joseph P.; Devaney, Howard F.; Hake, Lewis W.

    1982-08-17

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  12. Emittance measurements from the LLUMC proton accelerator

    NASA Astrophysics Data System (ADS)

    Coutrakon, G.; Gillespie, G. H.; Hubbard, J.; Sanders, E.

    2005-12-01

    A new method of calculating beam emittances at the extraction point of a particle accelerator is presented. The technique uses the optimization programs NPSOL and MINOS developed at Stanford University in order to determine the initial values of beam size, divergence and correlation parameters (i.e. beam sigma matrix, σij) that best fit measured beam parameters. These σij elements are then used to compute the Twiss parameters α, β, and the phase space area, ε, of the beam at the extraction point. Beam size measurements in X and Y throughout the transport line were input to the optimizer along with the magnetic elements of bends, quads, and drifts. The σij parameters were optimized at the accelerator's extraction point by finding the best agreement between these measured beam sizes and those predicted by TRANSPORT. This expands upon a previous study in which a "trial and error" technique was used instead of the optimizer software, and which yielded similar results. The Particle Beam Optics Laboratory (PBO Lab™) program used for this paper integrates particle beam optics and other codes into a single intuitive graphically-based computing environment. This new software provides a seamless interface between the NPSOL and MINOS optimizer and TRANSPORT calculations. The results of these emittance searches are presented here for the eight clinical energies between 70 and 250 MeV currently being used at LLUMC.

  13. LINEAR ACCELERATOR

    DOEpatents

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  14. Laser-driven ion acceleration from relativistically transparent nanotargets

    NASA Astrophysics Data System (ADS)

    Hegelich, B. M.; Pomerantz, I.; Yin, L.; Wu, H. C.; Jung, D.; Albright, B. J.; Gautier, D. C.; Letzring, S.; Palaniyappan, S.; Shah, R.; Allinger, K.; Hörlein, R.; Schreiber, J.; Habs, D.; Blakeney, J.; Dyer, G.; Fuller, L.; Gaul, E.; Mccary, E.; Meadows, A. R.; Wang, C.; Ditmire, T.; Fernandez, J. C.

    2013-08-01

    Here we present experimental results on laser-driven ion acceleration from relativistically transparent, overdense plasmas in the break-out afterburner (BOA) regime. Experiments were preformed at the Trident ultra-high contrast laser facility at Los Alamos National Laboratory, and at the Texas Petawatt laser facility, located in the University of Texas at Austin. It is shown that when the target becomes relativistically transparent to the laser, an epoch of dramatic acceleration of ions occurs that lasts until the electron density in the expanding target reduces to the critical density in the non-relativistic limit. For given laser parameters, the optimal target thickness yielding the highest maximum ion energy is one in which this time window for ion acceleration overlaps with the intensity peak of the laser pulse. A simple analytic model of relativistically induced transparency is presented for plasma expansion at the time-evolving sound speed, from which these times may be estimated. The maximum ion energy attainable is controlled by the finite acceleration volume and time over which the BOA acts.

  15. Cosmic acceleration and Brans-Dicke theory

    SciTech Connect

    Sharif, M. Waheed, S.

    2012-10-15

    We study the accelerated expansion of the universe by exploring the Brans-Dicke parameter in different eras. For this, we take the FRW universe model with a viscous fluid (without potential) and the Bianchi type-I universe model with a barotropic fluid (with and without a potential). We evaluate the deceleration parameter and the Brans-Dicke parameter to explore cosmic acceleration. It is concluded that accelerated expansion of the universe can also be achieved for higher values of the Brans-Dicke parameter in some cases.

  16. Measurements of an expanding surface flashover plasma

    SciTech Connect

    Harris, J. R.

    2014-05-21

    A better understanding of vacuum surface flashover and the plasma produced by it is of importance for electron and ion sources, as well as advanced accelerators and other vacuum electronic devices. This article describes time-of-flight and biased-probe measurements made on the expanding plasma generated from a vacuum surface flashover discharge. The plasma expanded at velocities of 1.2–6.5 cm/μs, and had typical densities of 10{sup 10}–10{sup 12} cm{sup −3}. The expansion velocity of the plasma leading edge often exhibited a sharp increase at distances of about 50 mm from the discharge site. Comparison with biased-probe data suggests that, under most conditions, the plasma leading edge was dominated by negative ions, with the apparent increase in velocity being due to fast H{sup −} overtaking slower, heavier ions. In some cases, biased-probe data also showed abrupt discontinuities in the plasma energy distribution co-located with large changes in the intercepted plasma current, suggesting the presence of a shock in the leading edge of the expanding plasma.

  17. Advanced expander test bed program

    NASA Technical Reports Server (NTRS)

    Masters, A. I.; Mitchell, J. C.

    1991-01-01

    The Advanced Expander Test Bed (AETB) is a key element in NASA's Chemical Transfer Propulsion Program for development and demonstration of expander cycle oxygen/hydrogen engine technology component technology for the next space engine. The AETB will be used to validate the high-pressure expander cycle concept, investigate system interactions, and conduct investigations of advanced missions focused components and new health monitoring techniques. The split-expander cycle AETB will operate at combustion chamber pressures up to 1200 psia with propellant flow rates equivalent to 20,000 lbf vacuum thrust.

  18. Advanced expander test bed engine

    NASA Technical Reports Server (NTRS)

    Mitchell, J. P.

    1992-01-01

    The Advanced Expander Test Bed (AETB) is a key element in NASA's Space Chemical Engine Technology Program for development and demonstration of expander cycle oxygen/hydrogen engine and advanced component technologies applicable to space engines as well as launch vehicle upper stage engines. The AETB will be used to validate the high pressure expander cycle concept, study system interactions, and conduct studies of advanced mission focused components and new health monitoring techniques in an engine system environment. The split expander cycle AETB will operate at combustion chamber pressures up to 1200 psia with propellant flow rates equivalent to 20,000 lbf vacuum thrust.

  19. RecFOR proteins load RecA protein onto gapped DNA to accelerate DNA strand exchange: a universal step of recombinational repair.

    PubMed

    Morimatsu, Katsumi; Kowalczykowski, Stephen C

    2003-05-01

    Genetic evidence suggests that the RecF, RecO, and RecR (RecFOR) proteins participate in a common step of DNA recombination and repair, yet the biochemical event requiring collaboration of all three proteins is unknown. Here, we show that the concerted action of the RecFOR complex directs the loading of RecA protein specifically onto gapped DNA that is coated with single-stranded DNA binding (SSB) protein, thereby accelerating DNA strand exchange. The RecFOR complex recognizes the junction between the ssDNA and dsDNA regions and requires a base-paired 5' terminus at the junction. Thus, the RecFOR complex is a structure-specific mediator that targets recombinational repair to ssDNA-dsDNA junctions. This reaction reconstitutes the initial steps of recombinational gapped DNA repair and uncovers an event also common to the repair of ssDNA-tailed intermediates of dsDNA-break repair. We propose that the behavior of the RecFOR proteins is mimicked by functional counterparts that exist in all organisms. PMID:12769856

  20. Ten scenarios from early radiation to late time acceleration with a minimally coupled dark energy

    SciTech Connect

    Fay, Stéphane

    2013-09-01

    We consider General Relativity with matter, radiation and a minimally coupled dark energy defined by an equation of state w. Using dynamical system method, we find the equilibrium points of such a theory assuming an expanding Universe and a positive dark energy density. Two of these points correspond to classical radiation and matter dominated epochs for the Universe. For the other points, dark energy mimics matter, radiation or accelerates Universe expansion. We then look for possible sequences of epochs describing a Universe starting with some radiation dominated epoch(s) (mimicked or not by dark energy), then matter dominated epoch(s) (mimicked or not by dark energy) and ending with an accelerated expansion. We find ten sequences able to follow this Universe history without singular behaviour of w at some saddle points. Most of them are new in dark energy literature. To get more than these ten sequences, w has to be singular at some specific saddle equilibrium points. This is an unusual mathematical property of the equation of state in dark energy literature, whose physical consequences tend to be discarded by observations. This thus distinguishes the ten above sequences from an infinity of ways to describe Universe expansion.

  1. Particle acceleration

    NASA Technical Reports Server (NTRS)

    Vlahos, L.; Machado, M. E.; Ramaty, R.; Murphy, R. J.; Alissandrakis, C.; Bai, T.; Batchelor, D.; Benz, A. O.; Chupp, E.; Ellison, D.

    1986-01-01

    Data is compiled from Solar Maximum Mission and Hinothori satellites, particle detectors in several satellites, ground based instruments, and balloon flights in order to answer fundamental questions relating to: (1) the requirements for the coronal magnetic field structure in the vicinity of the energization source; (2) the height (above the photosphere) of the energization source; (3) the time of energization; (4) transistion between coronal heating and flares; (5) evidence for purely thermal, purely nonthermal and hybrid type flares; (6) the time characteristics of the energization source; (7) whether every flare accelerates protons; (8) the location of the interaction site of the ions and relativistic electrons; (9) the energy spectra for ions and relativistic electrons; (10) the relationship between particles at the Sun and interplanetary space; (11) evidence for more than one acceleration mechanism; (12) whether there is single mechanism that will accelerate particles to all energies and also heat the plasma; and (13) how fast the existing mechanisms accelerate electrons up to several MeV and ions to 1 GeV.

  2. Accelerated Achievement

    ERIC Educational Resources Information Center

    Ford, William J.

    2010-01-01

    This article focuses on the accelerated associate degree program at Ivy Tech Community College (Indiana) in which low-income students will receive an associate degree in one year. The three-year pilot program is funded by a $2.3 million grant from the Lumina Foundation for Education in Indianapolis and a $270,000 grant from the Indiana Commission…

  3. ACCELERATION INTEGRATOR

    DOEpatents

    Pope, K.E.

    1958-01-01

    This patent relates to an improved acceleration integrator and more particularly to apparatus of this nature which is gyrostabilized. The device may be used to sense the attainment by an airborne vehicle of a predetermined velocitv or distance along a given vector path. In its broad aspects, the acceleration integrator utilizes a magnetized element rotatable driven by a synchronous motor and having a cylin drical flux gap and a restrained eddy- current drag cap deposed to move into the gap. The angular velocity imparted to the rotatable cap shaft is transmitted in a positive manner to the magnetized element through a servo feedback loop. The resultant angular velocity of tae cap is proportional to the acceleration of the housing in this manner and means may be used to measure the velocity and operate switches at a pre-set magnitude. To make the above-described dcvice sensitive to acceleration in only one direction the magnetized element forms the spinning inertia element of a free gyroscope, and the outer housing functions as a gimbal of a gyroscope.

  4. Plasma accelerator

    DOEpatents

    Wang, Zhehui; Barnes, Cris W.

    2002-01-01

    There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.

  5. Beyond Academic Outcomes: Expanding into Comprehensive Assessment while Preserving Faculty Ownership. AIR 1994 Annual Forum Paper.

    ERIC Educational Resources Information Center

    Peacock, Dennis E.

    At Northeast Missouri State University, where faculty have directed student outcomes assessment for 20 years, assessment is expanding to include a broader university mission of developing the whole person. As assessment becomes more comprehensive, expanding into out-of-class experiences, there is a risk of losing faculty support. Three fundamental…

  6. Diffusive Shock Acceleration

    NASA Astrophysics Data System (ADS)

    Baring, Matthew

    2003-04-01

    The process of diffusive acceleration of charged particles in shocked plasmas is widely invoked in astrophysics to account for the ubiquitous presence of signatures of non-thermal relativistic electrons and ions in the universe. This statistical energization mechanism, manifested in turbulent media, was first posited by Enrico Fermi in 1949 to explain the observed cosmic ray population, which exhibits an almost power-law distribution in rigidity. The absence of a momentum scale is a key characteristic of diffusive shock acceleration, and astrophysical systems generally only impose scales at the injection (low energy) and loss (high energy) ends of the particle spectrum. The existence of structure in the cosmic ray spectrum (the "knee") at around 3000 TeV has promoted contentions that there are at least two origins for cosmic rays, a galactic one supplying those up to the knee, and perhaps an extragalactic one that can explain even the ultra-high energy cosmic rays (UHECRs) seen at 1-300 EeV. Accounting for the UHECRs with familiar astrophysical sites of acceleration has historically proven difficult due to the need to assume high magnetic fields in order to reduce the shortest diffusive acceleration timescale, the ion gyroperiod, to meaningful values. Yet active galaxies and gamma-ray bursts remain strong and interesting candidate sources for UHECRs, turning the theoretical focus to relativistic shocks. This review summarizes properties of diffusive shock acceleration that are salient to the issue of UHECR generation. These include spectral indices, anisotropies, acceleration efficencies and timescales, as functions of the shock speed and mean field orientation, and also the degree of field turbulence. Astrophysical sites for UHECR production are also critiqued.

  7. Universe Awareness

    NASA Astrophysics Data System (ADS)

    Sankatsing Nava, Tibisay; Russo, Pedro

    2015-08-01

    Universe Awareness (UNAWE) is an educational programme coordinated by Leiden University that uses the beauty and grandeur of the Universe to encourage young children, particularly those from an underprivileged background, to have an interest in science and technology and foster their sense of global citizenship from the earliest age.UNAWE's twofold vision uses our Universe to inspire and motivate very young children: the excitement of the Universe provides an exciting introduction to science and technology, while the vastness and beauty of the Universe helps broaden the mind and stimulate a sense of global citizenship and tolerance. UNAWE's goals are accomplished through four main activities: the coordination of a global network of more than 1000 astronomers, teachers and educators from more than 60 countries, development of educational resources, teacher training activities and evaluation of educational activities.Between 2011 and 2013, EU-UNAWE, the European branch of UNAWE, was funded by the European Commission to implement a project in 5 EU countries and South Africa. This project has been concluded successfully. Since then, the global project Universe Awareness has continued to grow with an expanding international network, new educational resources and teacher trainings and a planned International Workshop in collaboration with ESA in October 2015, among other activities.

  8. Monolithical aspherical beam expanding systems

    NASA Astrophysics Data System (ADS)

    Fuchs, U.; Matthias, Sabrina

    2014-10-01

    Beam expanding is a common task, where Galileo telescopes are preferred. However researches and customers have found limitations when using these systems. A new monolithical solution which is based on the usage of only one aspherical component will be presented. It will be shown how to combine up to five monolithical beam expanding systems and to keep the beam quality at diffraction limitation. Insights will be given how aspherical beam expanding systems will help using larger incoming beams and reducing the overall length of such a system. Additionally an add-on element for divergence and wavelength adaption will be presented.

  9. Compact accelerator

    DOEpatents

    Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.

    2007-02-06

    A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).

  10. Accelerator research studies

    SciTech Connect

    Not Available

    1992-01-01

    The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under grant number DE-FG05-91ER40642, is currently in the first year of a three-year funding cycle. The program consists of the following three tasks: TASK A, Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams, TASK B, Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams; TASK C, Study of a Gyroklystron High-power Microwave Source for Linear Colliders. In this report we document the progress that has been made during the past year for each of the three tasks.

  11. Hardware Accelerated Simulated Radiography

    SciTech Connect

    Laney, D; Callahan, S; Max, N; Silva, C; Langer, S; Frank, R

    2005-04-12

    We present the application of hardware accelerated volume rendering algorithms to the simulation of radiographs as an aid to scientists designing experiments, validating simulation codes, and understanding experimental data. The techniques presented take advantage of 32 bit floating point texture capabilities to obtain validated solutions to the radiative transport equation for X-rays. An unsorted hexahedron projection algorithm is presented for curvilinear hexahedra that produces simulated radiographs in the absorption-only regime. A sorted tetrahedral projection algorithm is presented that simulates radiographs of emissive materials. We apply the tetrahedral projection algorithm to the simulation of experimental diagnostics for inertial confinement fusion experiments on a laser at the University of Rochester. We show that the hardware accelerated solution is faster than the current technique used by scientists.

  12. Accelerated expansion through interaction

    SciTech Connect

    Zimdahl, Winfried

    2009-05-01

    Interactions between dark matter and dark energy with a given equation of state are known to modify the cosmic dynamics. On the other hand, the strength of these interactions is subject to strong observational constraints. Here we discuss a model in which the transition from decelerated to accelerated expansion of the Universe arises as a pure interaction phenomenon. Various cosmological scenarios that describe a present stage of accelerated expansion, like the {lambda}CDM model or a (generalized) Chaplygin gas, follow as special cases for different interaction rates. This unifying view on the homogeneous and isotropic background level is accompanied by a non-adiabatic perturbation dynamics which can be seen as a consequence of a fluctuating interaction rate.

  13. BICEP's acceleration

    SciTech Connect

    Contaldi, Carlo R.

    2014-10-01

    The recent Bicep2 [1] detection of, what is claimed to be primordial B-modes, opens up the possibility of constraining not only the energy scale of inflation but also the detailed acceleration history that occurred during inflation. In turn this can be used to determine the shape of the inflaton potential V(φ) for the first time — if a single, scalar inflaton is assumed to be driving the acceleration. We carry out a Monte Carlo exploration of inflationary trajectories given the current data. Using this method we obtain a posterior distribution of possible acceleration profiles ε(N) as a function of e-fold N and derived posterior distributions of the primordial power spectrum P(k) and potential V(φ). We find that the Bicep2 result, in combination with Planck measurements of total intensity Cosmic Microwave Background (CMB) anisotropies, induces a significant feature in the scalar primordial spectrum at scales k∼ 10{sup -3} Mpc {sup -1}. This is in agreement with a previous detection of a suppression in the scalar power [2].

  14. The United States Particle Accelerator School: Educating the Next Generation of Accelerator Scientists and Engineers

    SciTech Connect

    Barletta, William A.

    2009-03-10

    Only a handful of universities in the US offer any formal training in accelerator science. The United States Particle Accelerator School (USPAS) is National Graduate Educational Program that has developed a highly successful educational paradigm that, over the past twenty-years, has granted more university credit in accelerator/beam science and technology than any university in the world. Sessions are held twice annually, hosted by major US research universities that approve course credit, certify the USPAS faculty, and grant course credit. The USPAS paradigm is readily extensible to other rapidly developing, cross-disciplinary research areas such as high energy density physics.

  15. The United States Particle Accelerator School: Educating the next generation of accelerator scientists and engineers

    SciTech Connect

    Barletta, William A.; /MIT

    2008-09-01

    Only a handful of universities in the US offer any formal training in accelerator science. The United States Particle Accelerator School (USPAS) is National Graduate Educational Program that has developed a highly successful educational paradigm that, over the past twenty-years, has granted more university credit in accelerator / beam science and technology than any university in the world. Sessions are held twice annually, hosted by major US research universities that approve course credit, certify the USPAS faculty, and grant course credit. The USPAS paradigm is readily extensible to other rapidly developing, crossdisciplinary research areas such as high energy density physics.

  16. Advanced expander test bed program

    NASA Technical Reports Server (NTRS)

    Riccardi, D. P.; Mitchell, J. C.

    1993-01-01

    The Advanced Expander Test Bed (AETB) is a key element in NASA's Space Chemical Engine Technology Program for development and demonstration of expander cycle oxygen/hydrogen engine and advanced component technologies applicable to space engines as well as launch vehicle upper stage engines. The AETB will be used to validate the high-pressure expander cycle concept, investigate system interactions, and conduct investigations of advanced mission focused components and new health monitoring techniques in an engine system environment. The split expander cycle AETB will operate at combustion chamber pressures up to 1200 psia with propellant flow rates equivalent to 20,000 lbf vacuum thrust. Contract work began 27 Apr. 1990. During 1992, a major milestone was achieved with the review of the final design of the oxidizer turbopump in Sep. 1992.

  17. Symposium on accelerator mass spectrometry

    SciTech Connect

    1981-01-01

    The area of accelerator mass spectrometry has expanded considerably over the past few years and established itself as an independent and interdisciplinary research field. Three years have passed since the first meeting was held at Rochester. A Symposium on Accelerator Mass Spectrometry was held at Argonne on May 11-13, 1981. In attendance were 96 scientists of whom 26 were from outside the United States. The present proceedings document the program and excitement of the field. Papers are arranged according to the original program. A few papers not presented at the meeting have been added to complete the information on the status of accelerator mass spectrometry. Individual papers were prepared separately for the data base.

  18. Homogeneous cosmology with aggressively expanding civilizations

    NASA Astrophysics Data System (ADS)

    Olson, S. Jay

    2015-11-01

    In the context of a homogeneous Universe, we note that the appearance of aggressively expanding advanced life is geometrically similar to the process of nucleation and bubble growth in a first-order cosmological phase transition. We exploit this similarity to describe the dynamics of life saturating the Universe on a cosmic scale, adapting the phase transition model to incorporate probability distributions of expansion and resource consumption strategies. Through a series of numerical solutions spanning several orders of magnitude in the input assumption parameters, the resulting cosmological model is used to address basic questions related to the intergalactic spreading of life, dealing with issues such as timescales, observability, competition between strategies, and first-mover advantage. Finally, we examine physical effects on the Universe itself, such as reheating and the backreaction on the evolution of the scale factor, if such life is able to control and convert a significant fraction of the available pressureless matter into radiation. We conclude that the existence of life, if certain advanced technologies are practical, could have a significant influence on the future large-scale evolution of the Universe.

  19. Is Space Really Expanding? A Counterexample

    NASA Astrophysics Data System (ADS)

    Chodorowski, Michał J.

    2007-03-01

    In all Friedman models, the cosmological redshift is widely interpreted as a consequence of the general-relativistic phenomenon of expansion of space. Other commonly believed consequences of this phenomenon are superluminal recession velocities of distant galaxies, and the distance to the particle horizon greater than ct (where t is the age of the Universe), in apparent conflict with special relativity. Here, we study a particular Friedman model: empty universe. This model exhibits both cosmological redshift, superluminal velocities and infinite distance to the horizon. However, we show that the cosmological redshift is there simply a relativistic Doppler shift. Moreover, apparently superluminal velocities and ‘acausal’ distance to the horizon are in fact a direct consequence of special-relativistic phenomenon of time dilation, as well as of the adopted definition of distance in cosmology. There is no conflict with special relativity, whatsoever. In particular, inertial recession velocities are subluminal. Since in the real Universe, sufficiently distant galaxies recede with relativistic velocities, these special-relativistic effects must be at least partly responsible for the cosmological redshift and the aforementioned ‘superluminalities’, commonly attributed to the expansion of space. Let us finish with a question resembling a Buddhism-Zen ‘koan’: in an empty universe, what is expanding?

  20. Understanding University Technology Transfer

    ERIC Educational Resources Information Center

    Association of American Universities, 2011

    2011-01-01

    Federal government agencies provide about $33 billion a year to universities to conduct scientific research. That continuing investment expands human knowledge and helps educate the next generation of science and technology leaders. New discoveries from university research also form the basis for many new products and processes that benefit the…

  1. Advanced concepts for acceleration

    SciTech Connect

    Keefe, D.

    1986-07-01

    Selected examples of advanced accelerator concepts are reviewed. Such plasma accelerators as plasma beat wave accelerator, plasma wake field accelerator, and plasma grating accelerator are discussed particularly as examples of concepts for accelerating relativistic electrons or positrons. Also covered are the pulsed electron-beam, pulsed laser accelerator, inverse Cherenkov accelerator, inverse free-electron laser, switched radial-line accelerators, and two-beam accelerator. Advanced concepts for ion acceleration discussed include the electron ring accelerator, excitation of waves on intense electron beams, and two-wave combinations. (LEW)

  2. Accelerators and the Accelerator Community

    SciTech Connect

    Malamud, Ernest; Sessler, Andrew

    2008-06-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  3. Transparency parameters from relativistically expanding outflows

    SciTech Connect

    Bégué, D.; Iyyani, S.

    2014-09-01

    In many gamma-ray bursts a distinct blackbody spectral component is present, which is attributed to the emission from the photosphere of a relativistically expanding plasma. The properties of this component (temperature and flux) can be linked to the properties of the outflow and have been presented in the case where there is no sub-photospheric dissipation and the photosphere is in coasting phase. First, we present the derivation of the properties of the outflow for finite winds, including when the photosphere is in the accelerating phase. Second, we study the effect of localized sub-photospheric dissipation on the estimation of the parameters. Finally, we apply our results to GRB 090902B. We find that during the first epoch of this burst the photosphere is most likely to be in the accelerating phase, leading to smaller values of the Lorentz factor than the ones previously estimated. For the second epoch, we find that the photosphere is likely to be in the coasting phase.

  4. The Expanding Marketplace for Applied Geophysics

    NASA Astrophysics Data System (ADS)

    Carlson, N.; Sirles, P.

    2012-12-01

    While the image of geophysics for the proverbial "layman" often seems limited to volcanoes and earthquakes, and to the geoscientist this image enlarges to include oil or minerals exploration and whole earth studies, there has been a steady increase in the application of geophysics into the realm of "daily life", such as real estate deals, highway infrastructure, and flood protection. This expansion of applications can be attributed to the improved economics from advances in equipment and interpretation. Traditional geophysical methods that at one time often only fit within the budgets of oil, gas, and minerals exploration programs can now be economically applied to much smaller scale needs like contaminant mapping, landfill delineation, and levee investigations. A real-world, economic example of this expanding marketplace is our company, which began very small and was aimed almost exclusively at the minerals exploration market. Most of our growth has been in the last 10 years, when we have expanded to five offices and a staff with almost 40 geoscientist degrees (21 in geophysics); much of this growth has been in the non-oil, non-minerals arenas. While much of our work still includes minerals exploration, other projects this year include wind-farm foundation studies, cavity detection above underground nuclear tests, landfill studies, acid mine drainage problems, and leaks in evaporation ponds. A methodology example of this expanding market is the induced polarization (IP) survey, once primarily used for minerals exploration, particularly large porphyry copper deposits, but now efficient enough to also use in environmental studies. The IP method has been particularly useful in delineating and characterizing old, poorly documented landfills, and recent research suggests it may also be useful in monitoring the accelerated biodegradation processes used in some cases to rehabilitate the sites. Compared to temperature monitoring systems, IP may be more useful in providing

  5. Dynamics in a Maximally Symmetric Universe

    NASA Astrophysics Data System (ADS)

    Bewketu, Asnakew

    2016-03-01

    Our present understanding of the evolution of the universe relies upon the Friedmann- Robertson- Walker cosmological models. This model is so successful that it is now being considered as the Standard Model of Cosmology. So in this work we derive the Fried- mann equations using the Friedmann-Robertson-Walker metric together with Einstein field equation and then we give a simple method to reduce Friedmann equations to a second order linear differential equation when it is supplemented with a time dependent equation of state. Furthermore, as illustrative examples, we solve this equation for some specific time dependent equation of states. And also by using the Friedmann equations with some time dependent equation of state we try to determine the cosmic scale factor(the rate at which the universe expands) and age of the Friedmann universe, for the matter dominated era, radiation dominated era and for both matter and radiation dominated era by considering different cases. We have finally discussed the observable quantities that can be evidences for the accelerated expansion of the Friedmann universe. I would like to acknowledge Addis Ababa University for its financial and material support to my work on the title mentioned above.

  6. Expanding Gerontology Enrollments: Successful Results of an Innovative Outreach Program

    ERIC Educational Resources Information Center

    Reynolds, Sandra L.; Haley, William E.; Hyer, Kathryn

    2007-01-01

    As state budget allocations for higher education decrease, "specialty" programs such as gerontology must continually demonstrate their productivity. State and private universities increasingly rely on student credit hours (SCH) or tuition generated, which is making it difficult for many gerontology programs to expand. The School of Aging Studies…

  7. Expanding Library Support of Faculty Research: Exploring Readiness

    ERIC Educational Resources Information Center

    Brown, Jeanne M.; Tucker, Cory

    2013-01-01

    The changing research and information environment requires a reexamination of library support for research. This study considers research-related attitudes and practices to identify elements indicating readiness or resistance to expanding the library's role in research support. A survey of faculty conducted at the University of Nevada Las…

  8. Application of particle accelerators in research.

    PubMed

    Mazzitelli, Giovanni

    2011-07-01

    Since the beginning of the past century, accelerators have started to play a fundamental role as powerful tools to discover the world around us, how the universe has evolved since the big bang and to develop fundamental instruments for everyday life. Although more than 15 000 accelerators are operating around the world only a very few of them are dedicated to fundamental research. An overview of the present high energy physics (HEP) accelerator status and prospectives is presented.

  9. The CSU Accelerator and FEL Facility

    NASA Astrophysics Data System (ADS)

    Biedron, Sandra; Milton, Stephen; D'Audney, Alex; Edelen, Jonathan; Einstein, Josh; Harris, John; Hall, Chris; Horovitz, Kahren; Martinez, Jorge; Morin, Auralee; Sipahi, Nihan; Sipahi, Taylan; Williams, Joel

    2014-03-01

    The Colorado State University (CSU) Accelerator Facility will include a 6-MeV L-Band electron linear accelerator (linac) with a free-electron laser (FEL) system capable of producing Terahertz (THz) radiation, a laser laboratory, a microwave test stand, and a magnetic test stand. The photocathode drive linac will be used in conjunction with a hybrid undulator capable of producing THz radiation. Details of the systems used in CSU Accelerator Facility are discussed.

  10. Particle acceleration in solar flares

    NASA Astrophysics Data System (ADS)

    Klecker, Berndt; Cliver, Ed; Kahler, Steve; Cane, Hilary

    Particle acceleration in solar flares was the topic of a workshop held at the University of Tasmania in Hobart, Australia, January 24-26, 1990. The workshop was held in conjunction with the 21st International Cosmic Ray Conference in Adelaide, South Australia, January 6-19, 1990. Forty-six scientists participated in the workshop, which was organized by Hilary Cane and John Humble of the University of Tasmania; Marc Duldig, Australian Antarctic Division, University of Tasmania; Ed Cliver, Geophysics Laboratory, U.S. Air Force Systems Command; and Steve Kahler, Boston College, Mass.

  11. Acceleration during magnetic reconnection

    SciTech Connect

    Beresnyak, Andrey; Li, Hui

    2015-07-16

    The presentation begins with colorful depictions of solar x-ray flares and references to pulsar phenomena. Plasma reconnection is complex, could be x-point dominated or turbulent, field lines could break due to either resistivity or non-ideal effects, such as electron pressure anisotropy. Electron acceleration is sometimes observed, and sometimes not. One way to study this complex problem is to have many examples of the process (reconnection) and compare them; the other way is to simplify and come to something robust. Ideal MHD (E=0) turbulence driven by magnetic energy is assumed, and the first-order acceleration is sought. It is found that dissipation in big (length >100 ion skin depths) current sheets is universal and independent on microscopic resistivity and the mean imposed field; particles are regularly accelerated while experiencing curvature drift in flows driven by magnetic tension. One example of such flow is spontaneous reconnection. This explains hot electrons with a power-law tail in solar flares, as well as ultrashort time variability in some astrophysical sources.

  12. Federal government expands compliance initiatives.

    PubMed

    Dugan, J K

    1997-09-01

    In 1995, the Federal government initiated Operation Restore Trust to increase enforcement of fraud and abuse regulations in Medicare and Medicaid programs. With the success of the original initiative, the government is expanding the project to additional states and program areas. The initial scrutiny of home health agencies, nursing homes, hospice care, and durable medical equipment is being expanded to managed care plans and acute care hospitals with an eye toward DRG creep. To manage this increased enforcement activity, healthcare organizations should institute comprehensive corporate compliance programs. Such programs should provide a framework that delineates responsibilities and provides a systematic means to resolve issues in a timely manner. PMID:10170318

  13. Federal government expands compliance initiatives.

    PubMed

    Dugan, J K

    1997-09-01

    In 1995, the Federal government initiated Operation Restore Trust to increase enforcement of fraud and abuse regulations in Medicare and Medicaid programs. With the success of the original initiative, the government is expanding the project to additional states and program areas. The initial scrutiny of home health agencies, nursing homes, hospice care, and durable medical equipment is being expanded to managed care plans and acute care hospitals with an eye toward DRG creep. To manage this increased enforcement activity, healthcare organizations should institute comprehensive corporate compliance programs. Such programs should provide a framework that delineates responsibilities and provides a systematic means to resolve issues in a timely manner.

  14. Accelerator system and method of accelerating particles

    NASA Technical Reports Server (NTRS)

    Wirz, Richard E. (Inventor)

    2010-01-01

    An accelerator system and method that utilize dust as the primary mass flux for generating thrust are provided. The accelerator system can include an accelerator capable of operating in a self-neutralizing mode and having a discharge chamber and at least one ionizer capable of charging dust particles. The system can also include a dust particle feeder that is capable of introducing the dust particles into the accelerator. By applying a pulsed positive and negative charge voltage to the accelerator, the charged dust particles can be accelerated thereby generating thrust and neutralizing the accelerator system.

  15. Introduction to Particle Acceleration in the Cosmos

    NASA Technical Reports Server (NTRS)

    Gallagher, D. L.; Horwitz, J. L.; Perez, J.; Quenby, J.

    2005-01-01

    Accelerated charged particles have been used on Earth since 1930 to explore the very essence of matter, for industrial applications, and for medical treatments. Throughout the universe nature employs a dizzying array of acceleration processes to produce particles spanning twenty orders of magnitude in energy range, while shaping our cosmic environment. Here, we introduce and review the basic physical processes causing particle acceleration, in astrophysical plasmas from geospace to the outer reaches of the cosmos. These processes are chiefly divided into four categories: adiabatic and other forms of non-stochastic acceleration, magnetic energy storage and stochastic acceleration, shock acceleration, and plasma wave and turbulent acceleration. The purpose of this introduction is to set the stage and context for the individual papers comprising this monograph.

  16. Argonne Tandem-Linac Accelerator System

    SciTech Connect

    Bollinger, L.M.

    1983-01-01

    Design considerations and operational experience for the existing heavy-ion accelerator consisting of a tandem injecting into a superconducting linac are summarized, with emphasis on the general features of the system. This introduction provides the basis for a discussion of the objectives and design of ATLAS, a larger tandem-linac system being formed by expanding the existing superconducting linac.

  17. A new look at the accelerating universe.

    PubMed

    Parker, L; Raval, A

    2001-01-29

    We show that the cosmological model having zero cosmological constant, but containing the vacuum energy of a simple quantized free scalar field of low mass (VCDM model), agrees with the cosmic microwave background radiation (CMBR) and supernova (SNe-Ia) data at least as well as the classical cosmological model with a small nonzero cosmological constant. We also show that in the VCDM model the ratio of vacuum pressure to vacuum energy density is less than -1. We display the VCDM results for a set of parameters that give a very good fit to the CMBR power spectrum, and show that the same parameters also give a good fit to the SNe-Ia data.

  18. Apparent and average accelerations of the Universe

    SciTech Connect

    Bolejko, Krzysztof; Andersson, Lars E-mail: larsa@math.miami.edu

    2008-10-15

    In this paper we consider the relation between the volume deceleration parameter obtained within the Buchert averaging scheme and the deceleration parameter derived from supernova observation. This work was motivated by recent findings that showed that there are models which despite having {Lambda} = 0 have volume deceleration parameter q{sup vol}<0. This opens the possibility that back-reaction and averaging effects may be used as an interesting alternative explanation to the dark energy phenomenon. We have calculated q{sup vol} in some Lemaitre-Tolman models. For those models which are chosen to be realistic and which fit the supernova data, we find that q{sup vol}>0, while those models which we have been able to find which exhibit q{sup vol}<0 turn out to be unrealistic. This indicates that care must be exercised in relating the deceleration parameter to observations.

  19. Accelerative propagation and explosion triggering by expanding turbulent premixed flames.

    PubMed

    Akkerman, V'yacheslav; Chaudhuri, Swetaprovo; Law, Chung K

    2013-02-01

    The dynamics and morphology of outwardly propagating, accelerating turbulent premixed flames and the effect of flame acceleration on explosion triggering are analyzed. Guided by recent theoretical results and substantiated by experiments, we find that an expanding flame front in an externally forced, near-isotropic turbulent environment exhibits accelerative propagation given by a well-defined power law based on the average global flame radius. In this context the limits of the power-law exponent and the effective turbulence intensity experienced by the flame are derived. The power-law exponent is found to be substantially larger than that for the hydrodynamically unstable cellular laminar flames, hence facilitating the possibility of detonation triggering in turbulent environments. For large length scales, hydrodynamic instability is expected to provide additional acceleration, thus further favoring the attainment of detonation triggering.

  20. Expanding the eukaryotic genetic code

    DOEpatents

    Chin, Jason W.; Cropp, T. Ashton; Anderson, J. Christopher; Schultz, Peter G.

    2010-09-14

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  1. Expanding the eukaryotic genetic code

    DOEpatents

    Chin, Jason W.; Cropp, T. Ashton; Anderson, J. Christopher; Schultz, Peter G.

    2009-10-27

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  2. Expanding the eukaryotic genetic code

    SciTech Connect

    Chin, Jason W.; Cropp, T. Ashton; Anderson, J. Christopher; Schultz, Peter G.

    2009-11-17

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  3. Expanding the eukaryotic genetic code

    SciTech Connect

    Chin, Jason W; Cropp, T. Ashton; Anderson, J. Christopher; Schultz, Peter G

    2015-02-03

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  4. Expanding the eukaryotic genetic code

    DOEpatents

    Chin, Jason W.; Cropp, T. Ashton; Anderson, J. Christopher; Schultz, Peter G.

    2012-02-14

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  5. Expanding the eukaryotic genetic code

    SciTech Connect

    Chin, Jason W.; Cropp, T. Ashton; Anderson, J. Christopher; Schultz, Peter G.

    2009-12-01

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  6. Expanding the eukaryotic genetic code

    SciTech Connect

    Chin, Jason W.; Cropp, T. Ashton; Anderson, J. Christopher; Schultz, Peter G.

    2013-01-22

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  7. Expanding the eukaryotic genetic code

    DOEpatents

    Chin, Jason W.; Cropp, T. Ashton; Anderson, J. Christopher; Schultz, Peter G.

    2012-05-08

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  8. Common Ground: Expanding Our Horizons.

    ERIC Educational Resources Information Center

    McDevitt, Michele J.

    In "Common Ground: Dialogue, Understanding, and the Teaching of Composition," Kurt Spellmeyer seeks to familiarize students and teachers with the linguistic and cultural no-man's-land separating them. Reinstating the value of two writing conventions often used by traditional students--expressive and commonplaces--can help expand on the horizons of…

  9. Teleteach Expanded Delivery System: Evaluation.

    ERIC Educational Resources Information Center

    Christopher, G. Ronald; Milam, Alvin L.

    In order to meet the demand for Air Force Institute of Technology (AFIT) professional continuing education (PCE) courses within the School of Systems and Logistics and the School of Engineering, the Teleteach Expanded Delivery System (TEDS) for instruction of Air Force personnel at remote locations was developed and evaluated. TEDS uses a device…

  10. Interleukin-8: an expanding universe beyond neutrophil chemotaxis and activation.

    PubMed

    Mukaida, N

    2000-12-01

    Since the discovery 13 years ago of interleukin (IL)-8 as a potent neutrophil chemotactic factor, accumulating evidence has established it as a crucial mediator in neutrophil-dependent acute inflammation. Numerous observations have demonstrated that various types of cells can produce a large amount of IL-8, either in response to various stimuli or constitutively, after malignant transformation. Recent studies of IL-8-mediated signaling have revealed that IL-8 activates a wide range of signaling molecules in a coordinate manner. IL-8 has been proven to have diverse actions on various types of leukocytic and nonleukocytic cells besides neutrophils. The author reviews recent progress in IL-8 signal transduction and biological actions on nonneutrophilic leukocytes, including T lymphocytes, monocytes, and hematopoietic progenitor cells. Potential involvement of IL-8 in viral infections and tumor progression is also discussed.

  11. International or Global--The Expanding Universe of Librarianship

    ERIC Educational Resources Information Center

    Rudasill, Lynne M.

    2009-01-01

    This year, the United States Department of Education Title VI programs will celebrate their 50th anniversary. During the Cold War, the United States government passed the National Defense Education Act to marshal all possible resources to improve education in multiple subject areas, initiating the development of National Research Centers (NRCs) in…

  12. An expanding universe of circadian networks in higher plants.

    PubMed

    Pruneda-Paz, Jose L; Kay, Steve A

    2010-05-01

    Extensive circadian clock networks regulate almost every biological process in plants. Clock-controlled physiological responses are coupled with daily oscillations in environmental conditions resulting in enhanced fitness and growth vigor. Identification of core clock components and their associated molecular interactions has established the basic network architecture of plant clocks, which consists of multiple interlocked feedback loops. A hierarchical structure of transcriptional feedback overlaid with regulated protein turnover sets the pace of the clock and ultimately drives all clock-controlled processes. Although originally described as linear entities, increasing evidence suggests that many signaling pathways can act as both inputs and outputs within the overall network. Future studies will determine the molecular mechanisms involved in these complex regulatory loops.

  13. The expanding universe of regulatory T cell subsets in cancer.

    PubMed

    Gajewski, Thomas F

    2007-08-01

    Evidence has indicated that failed antitumor immunity is dominated by immunosuppressive mechanisms within the tumor microenvironment. In this issue of Immunity, Peng et al. (2007) add to this list by describing tumor-infiltrating gammadelta T cells that have regulatory function.

  14. The expanding universe of mass analyzer configurations for biological analysis.

    PubMed

    Calvete, Juan J

    2014-01-01

    Mass spectrometry (MS) is an analytical technique that measures the mass-to-charge ratio of electrically charged gas-phase particles. All mass spectrometers combine ion formation, mass analysis, and ion detection. Although mass analyzers can be regarded as sophisticated devices that manipulate ions in space and time, the rich diversity of possible ways to combine ion separation, focusing, and detection in dynamic mass spectrometers accounts for the large number of instrument designs. A historical perspective of the progress in mass spectrometry that since 1965 until today have contributed to position this technique as an indispensable tool for biological research has been recently addressed by a privileged witness of this golden age of MS (Gelpí J. Mass Spectrom 43:419-435, 2008; Gelpí J. Mass Spectrom 44:1137-1161, 2008). The aim of this chapter is to highlight the view that the operational principles of mass spectrometry can be understood by a simple mathematical language, and that an understanding of the basic concepts of mass spectrometry is necessary to take the most out of this versatile technique.

  15. Beyond NK cells: the expanding universe of innate lymphoid cells.

    PubMed

    Cella, Marina; Miller, Hannah; Song, Christina

    2014-01-01

    For a long time, natural killer (NK) cells were thought to be the only innate immune lymphoid population capable of responding to invading pathogens under the influence of changing environmental cues. In the last few years, an increasing amount of evidence has shown that a number of different innate lymphoid cell (ILC) populations found at mucosal sites rapidly respond to locally produced cytokines in order to establish or maintain homeostasis. These ILC populations closely mirror the phenotype of adaptive T helper subsets in their repertoire of secreted soluble factors. Early in the immune response, ILCs are responsible for setting the stage to mount an adaptive T cell response that is appropriate for the incoming insult. Here, we review the diversity of ILC subsets and discuss similarities and differences between ILCs and NK cells in function and key transcriptional factors required for their development.

  16. Dynamics of moduli and gaugino condensates in an expanding universe

    SciTech Connect

    Papineau, Chloé; Ramos-Sánchez, Saúl; Postma, Marieke E-mail: mpostma@nikhef.nl

    2010-02-01

    We study dynamical moduli stabilization driven by gaugino condensation in supergravity. In the presence of background radiation, there exists a region of initial conditions leading to successful stabilization. We point out that most of the allowed region corresponds to initial Hubble rate H close to the scale of condensation Λ, which is the natural cutoff of the effective theory. We first show that including the condensate dynamics sets a strong bound on the initial conditions. We then find that (complete) decoupling of the condensate happens at H about two orders of magnitude below Λ. This bound implies that in the usual scenario with the condensate integrated out, only the vicinity of the minimum leads to stabilization. Finally, we discuss the effects of thermal corrections.

  17. The expanding universe of disorders of the basal ganglia.

    PubMed

    Obeso, Jose A; Rodriguez-Oroz, Maria C; Stamelou, Maria; Bhatia, Kailash P; Burn, David J

    2014-08-01

    The basal ganglia were originally thought to be associated purely with motor control. However, dysfunction and pathology of different regions and circuits are now known to give rise to many clinical manifestations beyond the association of basal ganglia dysfunction with movement disorders. Moreover, disorders that were thought to be caused by dysfunction of the basal ganglia only, such as Parkinson's disease and Huntington's disease, have diverse abnormalities distributed not only in the brain but also in the peripheral and autonomic nervous systems; this knowledge poses new questions and challenges. We discuss advances and the unanswered questions, and ways in which progress might be made.

  18. Expanding the Entamoeba Universe: New Hosts Yield Novel Ribosomal Lineages.

    PubMed

    Jacob, Alison S; Busby, Eloise J; Levy, Abigail D; Komm, Natasha; Clark, C Graham

    2016-01-01

    Removing the requirement for cell culture has led to a substantial increase in the number of lineages of Entamoeba recognized as distinct. Surveying the range of potential host species for this parasite genus has barely been started and it is clear that additional sampling of the same host in different locations often identifies additional diversity. In this study, using small subunit ribosomal RNA gene sequencing, we identify four new lineages of Entamoeba, including the first report of Entamoeba from an elephant, and extend the host range of some previously described lineages. In addition, examination of microbiome data from a number of host animals suggests that substantial Entamoeba diversity remains to be uncovered.

  19. ENVIRONMENTAL ANDROGENS AND ANTIANDROGENS: AN EXPANDING CHEMICAL UNIVERSE

    EPA Science Inventory

    Within the last ten years, awareness has grown about environmental chemicals that display antiandrogenic or androgenic activity. While studies in the early 1990s focused on pesticides that acted as androgen receptor (AR) antagonists, it soon became evident that this was not the ...

  20. The expanding universe of mass analyzer configurations for biological analysis.

    PubMed

    Calvete, Juan J

    2014-01-01

    Mass spectrometry (MS) is an analytical technique that measures the mass-to-charge ratio of electrically charged gas-phase particles. All mass spectrometers combine ion formation, mass analysis, and ion detection. Although mass analyzers can be regarded as sophisticated devices that manipulate ions in space and time, the rich diversity of possible ways to combine ion separation, focusing, and detection in dynamic mass spectrometers accounts for the large number of instrument designs. A historical perspective of the progress in mass spectrometry that since 1965 until today have contributed to position this technique as an indispensable tool for biological research has been recently addressed by a privileged witness of this golden age of MS (Gelpí J. Mass Spectrom 43:419-435, 2008; Gelpí J. Mass Spectrom 44:1137-1161, 2008). The aim of this chapter is to highlight the view that the operational principles of mass spectrometry can be understood by a simple mathematical language, and that an understanding of the basic concepts of mass spectrometry is necessary to take the most out of this versatile technique. PMID:24136515

  1. NASA Viz iPad App Expands Coverage Across Universe

    NASA Video Gallery

    The NASA Visualization Explorer app has broadened its scope to includemore awe-inspiring discoveries beamed back to Earth from the agency'sentire fleet of satellites, spacecraft and space tele...

  2. An expanding universe of mRNA modifications

    PubMed Central

    Jaffrey, Samie R.

    2015-01-01

    The fate of mRNA can be regulated by internal base modifications, with the currently known modified bases being N6-methyladenosine, 5-methylcytosine, and inosine. Three new studies show that yeast and human mRNA also contain pseudouridine residues and that pseudouridylation is induced in various stress states, hinting at a new pathway for post-transcriptional control of mRNA. PMID:25372308

  3. The expanding universe of disorders of the basal ganglia.

    PubMed

    Obeso, Jose A; Rodriguez-Oroz, Maria C; Stamelou, Maria; Bhatia, Kailash P; Burn, David J

    2014-08-01

    The basal ganglia were originally thought to be associated purely with motor control. However, dysfunction and pathology of different regions and circuits are now known to give rise to many clinical manifestations beyond the association of basal ganglia dysfunction with movement disorders. Moreover, disorders that were thought to be caused by dysfunction of the basal ganglia only, such as Parkinson's disease and Huntington's disease, have diverse abnormalities distributed not only in the brain but also in the peripheral and autonomic nervous systems; this knowledge poses new questions and challenges. We discuss advances and the unanswered questions, and ways in which progress might be made. PMID:24954674

  4. SLOW MAGNETOACOUSTIC WAVE OSCILLATION OF AN EXPANDING CORONAL LOOP

    SciTech Connect

    Schmidt, J. M.; Ofman, L.

    2011-10-01

    We simulated an expanding loop or slow coronal mass ejection (CME) in the solar corona dimensioned with size parameters taken from real coronal expanding loops observed with the STEREO spacecraft. We find that the loop expands to Sun's size within about one hour, consistent with slow CME observations. At the top of the loop, plasma is being blown off the loop, enabled with the reconnection between the loop's flux rope magnetic field and the radial magnetic field of the Sun, thus yielding feeding material for the formation of the slow solar wind. This mechanism is in accordance with the observed blob formation of the slow solar wind. We find wave packets traveling with local sound speed downward toward the footpoints of the loop, already seen in coronal seismology observations and simulations of stationary coronal loops. Here, we generalize these results for an expanding medium. We also find a reflection of the wave packets, identified as slow magnetoacoustic waves, at the footpoints of the loop. This confirms the formation of standing waves within the coronal loop. In particular, the reflected waves can partly escape the loop top and contribute to the heating of the solar wind. The present study improves our understanding on how loop material can emerge to form blobs, major ingredients of slow CMEs, and how the release of the wave energy stored in slow magnetoacoustic waves, and transported away from the Sun within expanding loops, contributes to the acceleration and formation of the slow solar wind.

  5. Helical screw expander evaluation project

    NASA Technical Reports Server (NTRS)

    Mckay, R.

    1982-01-01

    A one MW helical rotary screw expander power system for electric power generation from geothermal brine was evaluated. The technology explored in the testing is simple, potentially very efficient, and ideally suited to wellhead installations in moderate to high enthalpy, liquid dominated field. A functional one MW geothermal electric power plant that featured a helical screw expander was produced and then tested with a demonstrated average performance of approximately 45% machine efficiency over a wide range of test conditions in noncondensing, operation on two-phase geothermal fluids. The Project also produced a computer equipped data system, an instrumentation and control van, and a 1000 kW variable load bank, all integrated into a test array designed for operation at a variety of remote test sites. Data are presented for the Utah testing and for the noncondensing phases of the testing in Mexico. Test time logged was 437 hours during the Utah tests and 1101 hours during the Mexico tests.

  6. Seal-less cryogenic expander

    SciTech Connect

    Faria, L.E.; Christopher, E.H.

    1987-12-08

    In an expander for use in a split Stirling cycle refrigeration system of the type wherein a displacer moves with reciprocating motion inside an expander housing, and wherein a plunger force and a regenerator force are formed on the displacer, the plunger force cyclically varying and having a time of minimum and maximum plunger force amplitude, and the regenerator force cyclically varying and having a time of minimum and maximum regenerator force amplitude, the improvement is described comprising: (a) means for maintaining displacer forces, such that the maximum plunger force amplitude is substantially equal to the maximum regenerator force amplitude; and (b) means for adjusting a time difference, the time difference being the time between the time of maximum plunger force and the time of maximum regenerator force such that a measure of the cooling power of the refrigeration system is maximized.

  7. Magical NiTi expander

    PubMed Central

    Katti, Chandrika Girish; Katti, Girish; Kallur, Ravi; Ghali, Srinivas Rao

    2013-01-01

    A 24-year-old male patient was referred to our department for expansion of the constricted maxillary arch as a presurgical procedure for the correction of congenital facial disfigurement. On examination, the patient had a convex profile, increased interlabial gap, tongue thrust, limited mouth opening, posterior crossbite, asymmetric ‘V’-shaped maxillary arch with severe constriction, crowding of anterior teeth in the maxillary arch and a massive open bite. Radiographic investigations included orthopantomograph and occlusal radiographs. The patient photographs and models were analysed. On careful evaluation, the treatment for maxillary arch expansion was planned with a nickel titanium (NiTi) slow maxillary expander along with fixed mechanotherapy for alignment of teeth. An unexpectedly successful outcome was appreciated from the treatment. An emphasis should be laid on selecting and treating the case of constricted arches with a surgical or non-surgical approach, as expansion can be achieved orthodontically by using NiTi expanders. PMID:23867876

  8. Multiple pulse resonantly enhanced laser plasma wakefield acceleration

    SciTech Connect

    Corner, L.; Walczak, R.; Nevay, L. J.; Dann, S.; Hooker, S. M.; Bourgeois, N.; Cowley, J.

    2012-12-21

    We present an outline of experiments being conducted at Oxford University on multiple-pulse, resonantly-enhanced laser plasma wakefield acceleration. This method of laser plasma acceleration uses trains of optimally spaced low energy short pulses to drive plasma oscillations and may enable laser plasma accelerators to be driven by compact and efficient fibre laser sources operating at high repetition rates.

  9. Transforming a School of Education via the Accelerated Schools Model.

    ERIC Educational Resources Information Center

    Mims, J. Sabrina; Slovacek, Simeon; Wong, Gay Yuen

    This paper describes how the Accelerated Schools Model has served as a catalyst for transforming the Charter School of Education at California State University, Los Angeles. The Accelerated Schools Project has been one of the largest and most comprehensive school restructuring movements of the last decade. The focus of Accelerated Schools is…

  10. The universe dominated by oscillating scalar with non-minimal derivative coupling to gravity

    SciTech Connect

    Jinno, Ryusuke; Mukaida, Kyohei; Nakayama, Kazunori E-mail: mukaida@hep-th.phys.s.u-tokyo.ac.jp

    2014-01-01

    We study the expansion law of the universe dominated by the oscillating scalar field with non-minimal derivative coupling to gravity as G{sup μν}∂{sub μ}φ∂{sub ν}φ. In this system the Hubble parameter oscillates with a frequency of the effective mass of the scalar field, which formerly caused a difficulty in analyzing how the universe expands. We find an analytical solution for power law potentials and interpret the solution in an intuitive way by using a new invariant of the system. As a result, we find marginally accelerated expansion for the quadratic potential and no accelerated expansion for the potential with higher power.

  11. Thomas Jefferson National Accelerator Facility

    SciTech Connect

    Joseph Grames, Douglas Higinbotham, Hugh Montgomery

    2010-09-01

    The Thomas Jefferson National Accelerator Facility (Jefferson Lab) in Newport News, Virginia, USA, is one of ten national laboratories under the aegis of the Office of Science of the U.S. Department of Energy (DOE). It is managed and operated by Jefferson Science Associates, LLC. The primary facility at Jefferson Lab is the Continuous Electron Beam Accelerator Facility (CEBAF) as shown in an aerial photograph in Figure 1. Jefferson Lab was created in 1984 as CEBAF and started operations for physics in 1995. The accelerator uses superconducting radio-frequency (srf) techniques to generate high-quality beams of electrons with high-intensity, well-controlled polarization. The technology has enabled ancillary facilities to be created. The CEBAF facility is used by an international user community of more than 1200 physicists for a program of exploration and study of nuclear, hadronic matter, the strong interaction and quantum chromodynamics. Additionally, the exceptional quality of the beams facilitates studies of the fundamental symmetries of nature, which complement those of atomic physics on the one hand and of high-energy particle physics on the other. The facility is in the midst of a project to double the energy of the facility and to enhance and expand its experimental facilities. Studies are also pursued with a Free-Electron Laser produced by an energy-recovering linear accelerator.

  12. Wright State Expands Continuing Education

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1974

    1974-01-01

    By leasing the Eugene W. Kettering Engineering and Science Center in downtown Dayton, Ohio, Wright State University plans to enlarge significantly its activities in continuing education for engineers, scientists, and others. (JR)

  13. Late time cosmic acceleration from natural infrared cutoff

    NASA Astrophysics Data System (ADS)

    Gorji, Mohammad Ali

    2016-09-01

    In this paper, inspired by the ultraviolet deformation of the Friedmann-Lemaître-Robertson-Walker geometry in loop quantum cosmology, we formulate an infrared-modified cosmological model. We obtain the associated deformed Friedmann and Raychaudhuri equations and we show that the late time cosmic acceleration can be addressed by the infrared corrections. As a particular example, we applied the setup to the case of matter dominated universe. This model has the same number of parameters as ΛCDM, but a dynamical dark energy generates in the matter dominated era at the late time. According to our model, as the universe expands, the energy density of the cold dark matter dilutes and when the Hubble parameter approaches to its minimum, the infrared effects dominate such that the effective equation of state parameter smoothly changes from weff = 0 to weff = - 2. Interestingly and nontrivially, the unstable de Sitter phase with weff = - 1 is corresponding to Ωm =Ωd = 0.5 and the universe crosses the phantom divide from the quintessence phase with weff > - 1 and Ωm >Ωd to the phantom phase with weff < - 1 and Ωm <Ωd which shows that the model is observationally viable. The results show that the universe finally ends up in a big rip singularity for a finite time proportional to the inverse of the minimum of the Hubble parameter. Moreover, we consider the dynamical stability of the model and we show that the universe starts from the matter dominated era at the past attractor with weff = 0 and ends up in a future attractor at the big rip with weff = - 2.

  14. Top ten accelerating cosmological models

    NASA Astrophysics Data System (ADS)

    Szydłowski, Marek; Kurek, Aleksandra; Krawiec, Adam

    2006-11-01

    Recent astronomical observations indicate that the Universe is presently almost flat and undergoing a period of accelerated expansion. Basing on Einstein's general relativity all these observations can be explained by the hypothesis of a dark energy component in addition to cold dark matter (CDM). Because the nature of this dark energy is unknown, it was proposed some alternative scenario to explain the current accelerating Universe. The key point of this scenario is to modify the standard FRW equation instead of mysterious dark energy component. The standard approach to constrain model parameters, based on the likelihood method, gives a best-fit model and confidence ranges for those parameters. We always arbitrary choose the set of parameters which define a model which we compare with observational data. Because in the generic case, the introducing of new parameters improves a fit to the data set, there appears the problem of elimination of model parameters which can play an insufficient role. The Bayesian information criteria of model selection (BIC) is dedicated to promotion a set of parameters which should be incorporated to the model. We divide class of all accelerating cosmological models into two groups according to the two types of explanation acceleration of the Universe. Then the Bayesian framework of model selection is used to determine the set of parameters which gives preferred fit to the SNIa data. We find a few of flat cosmological models which can be recommend by the Bayes factor. We show that models with dark energy as a new fluid are favoured over models featuring a modified FRW equation. The work was supported by Marie Curie Host Fellowship MTKD-CT-2004-517186 (COCOS) during the staying in University of Paris 13.

  15. Shell may expand detergent alcohols

    SciTech Connect

    1996-10-23

    Shell Chemical is studying plans to expand detergent alcohols capacity in the US, CW has learned. The company is considering adding capacity for about 80 million lbs/year. If the project is approved, it would be implemented at the company`s Geismar, LA site. Shell will make a final decision on whether to proceed with the project within six months. It has been rumored to be considering a capacity addition as a result of tightening supply of natural and synthetic detergent alcohols.

  16. Unconventional microfluidics: expanding the discipline

    PubMed Central

    Nawaz, Ahmad Ahsan; Mao, Xiaole; Stratton, Zackary S.; Huang, Tony Jun

    2014-01-01

    Since its inception, the discipline of microfluidics has been harnessed for innovations in the biomedicine/chemistry fields—and to great effect. This success has had the natural side-effect of stereotyping microfluidics as a platform for medical diagnostics and miniaturized lab processes. But microfluidics has more to offer. And very recently, some researchers have successfully applied microfluidics to fields outside its traditional domains. In this Focus article, we highlight notable examples of such “unconventional” microfluidics applications (e.g., robotics, electronics). It is our hope that these early successes in unconventional microfluidics prompt further creativity, and inspire readers to expand the microfluidics discipline. PMID:23478651

  17. Unconventional microfluidics: expanding the discipline.

    PubMed

    Nawaz, Ahmad Ahsan; Mao, Xiaole; Stratton, Zackary S; Huang, Tony Jun

    2013-04-21

    Since its inception, the discipline of microfluidics has been harnessed for innovations in the biomedicine/chemistry fields-and to great effect. This success has had the natural side-effect of stereotyping microfluidics as a platform for medical diagnostics and miniaturized lab processes. But microfluidics has more to offer. And very recently, some researchers have successfully applied microfluidics to fields outside its traditional domains. In this Focus article, we highlight notable examples of such "unconventional" microfluidics applications (e.g., robotics, electronics). It is our hope that these early successes in unconventional microfluidics prompt further creativity, and inspire readers to expand the microfluidics discipline.

  18. Frost heave test being expanded

    SciTech Connect

    Not Available

    1981-03-01

    Northwest Alaskan Pipeline Co. is expanding its frost-heave testing program by adding seven test sites along the planned Alaskan gas transmission pipeline route. The test results will demonstrate the behavior of chilled pipe buried in unfrozen soils. To protect the permafrost in which the pipe will be buried, the pipeline operators will chill the gas in the line to below 32/sup 0/F. In thawed soils, however, frost heave may occur when moisture freezes on the chilled pipe, creates a frost bulb, expands the soil, and causes the chilled pipe to heave upward. Two methods being tested for preventing or minimizing frost heave are (1) insulation, and (2) replacement of frost-susceptible unfrozen soil with a selected bedding material. Each test site will consist of two 80-ft sections of 48 in-diam pipe - one bare, the other with insulation (urethane foam) or insulation plus a bedding-material replacement. The sites will have their own power-generation and refrigeration equipment, as well as data-acquisition systems that will automatically collect information from 800 sensors twice a week.

  19. Spreading of ultrarelativistically expanding shell: An application to GRBs

    NASA Astrophysics Data System (ADS)

    Ruffini, R.; Siutsou, I. A.; Vereshchagin, G. V.

    2014-02-01

    Optically thick energy dominated plasma created in the source of Gamma-Ray Bursts (GRBs) expands radially with acceleration and forms a shell with constant width measured in the laboratory frame. When strong Lorentz factor gradients are present within the shell it is supposed to spread at sufficiently large radii. There are two possible mechanisms of spreading: hydrodynamical and thermal ones. We consider both mechanisms evaluating the amount of spreading that occurs during expansion up to the moment when the expanding shell becomes transparent for photons. We compute the hydrodynamical spreading of an ultrarelativistically expanding shell. In the case of thermal spreading we compute the velocity spread as a function of two parameters: comoving temperature and bulk Lorentz factor of relativistic Maxwellian distribution. Based on this result we determine the value of thermal spreading of relativistically expanding shell. We found that thermal spreading is negligible for typical GRB parameters. Instead hydrodynamical spreading appears to be significant, with the shell width reaching ˜1010 cm for total energy E=1054 erg and baryonic loading B=10-2. Within the fireshell model such spreading will result in the duration of Proper Gamma-Ray Bursts up to several seconds.

  20. Laser driven ion accelerator

    DOEpatents

    Tajima, Toshiki

    2006-04-18

    A system and method of accelerating ions in an accelerator to optimize the energy produced by a light source. Several parameters may be controlled in constructing a target used in the accelerator system to adjust performance of the accelerator system. These parameters include the material, thickness, geometry and surface of the target.

  1. Heat expanded starch-based compositions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A heat expansion process similar to that used for expanded bead polystyrene was used to expand starch-based compositions. Foam beads made by solvent extraction had the appearance of polystyrene beads but their open-cell structure precluded them from expanding further when heated. Non-porous beads, p...

  2. Drizo protects turbo expander plant

    SciTech Connect

    Frazier, C.W.; Force, J.E.

    1982-01-01

    A triethylene glycol (TEG) unit using Dow's Drizo technology in front of processes was installed in a turbo expander plant owned by Valero Hydrocarbons, San Antonio, Texas. The TEG unit was placed in the process because methanol consumption had run higher than design conditions had predicted; gas flow rates and water content varied widely; and the gas was found to be contaminated considerably with iron sulfide. The TEG unit optimized gas processing by reducing the water content of gas to the system, accepting variable gas flow and water content to smooth out feed gas quality, removing iron sulfide and other contaminants before processing, and being amenable to conversion from other equipment already in existence at other Valero plant locations. The TEG Drizo process provides an azeotropic agent injected into the hot glycol, and the glycol solution is used to reduce residual water content of gas. Details of the equipment and process conversion are given.

  3. Deep Brain Stimulation: Expanding Applications

    PubMed Central

    TEKRIWAL, Anand; BALTUCH, Gordon

    2015-01-01

    For over two decades, deep brain stimulation (DBS) has shown significant efficacy in treatment for refractory cases of dyskinesia, specifically in cases of Parkinson's disease and dystonia. DBS offers potential alleviation from symptoms through a well-tolerated procedure that allows personalized modulation of targeted neuroanatomical regions and related circuitries. For clinicians contending with how to provide patients with meaningful alleviation from often debilitating intractable disorders, DBSs titratability and reversibility make it an attractive treatment option for indications ranging from traumatic brain injury to progressive epileptic supra-synchrony. The expansion of our collective knowledge of pathologic brain circuitries, as well as advances in imaging capabilities, electrophysiology techniques, and material sciences have contributed to the expanding application of DBS. This review will examine the potential efficacy of DBS for neurologic and psychiatric disorders currently under clinical investigation and will summarize findings from recent animal models. PMID:26466888

  4. Leak detection with expandable coatings

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Developed and evaluated is a system for leak detection that can be easily applied over separable connectors and that expands into a bubble or balloon if a leak is present. This objective is accomplished by using thin films of Parafilm tape wrapped over connectors, which are then overcoated with a special formulation. The low yield strength and the high elongation of the envelope permit bubble formation if leakage occurs. This system is appropriate for welds and other hardware besides separable connectors. The practical limit of this system appears to be for leaks exceeding 0.000001 cc/sec. If this envelope is used to trap gases for mass spectrometer inspection, leaks in the range of ten to the minus 8th power cc/sec. may be detectable.

  5. Preventive Ethics Through Expanding Education.

    PubMed

    Ho, Anita; MacDonald, Lisa Mei-Hwa; Unger, David

    2016-03-01

    Healthcare institutions have been making increasing efforts to standardize consultation methodology and to accredit both bioethics training programs and the consultants accordingly. The focus has traditionally been on the ethics consultation as the relevant unit of ethics intervention. Outcome measures are studied in relation to consultations, and the hidden assumption is that consultations are the preferred or best way to address day-to-day ethical dilemmas. Reflecting on the data from an internal quality improvement survey and the literature, we argue that having general ethics education as a key function of ethics services may be more important in meeting the contemporaneous needs of acute care settings. An expanded and varied ethics education, with attention to the time constraints of healthcare workers' schedules, was a key recommendation brought forward by survey respondents. Promoting ethical reflection and creating a culture of ethics may serve to prevent ethical dilemmas or mitigate their effects.

  6. Engelhard expands oxidation catalysts portfolio

    SciTech Connect

    Rotman, D.

    1997-02-26

    Engelhard says its agreement earlier this month to market Amoco Chemical`s proprietary maleic anhydride catalyst reflects an effort to expand its speciality catalysts business (CW, Feb. 19, p.5). In particular, the company says it is looking for additional alliances to bolster its oxidation catalysts portfolio. {open_quotes}There are some areas of oxidation catalysis that are reasonably attractive,{close_quotes} says Paul Lamb, marketing director/chemical catalysts. He says that while Engelhard is not interested in commodity oxidation catalysts, such as those used to make sulfuric acid, it does want to boost offerings for higher-value oxidation catalysts. Engelhard is collaborating with Geon to offer oxychlorination catalysts for making ethylene dichloride. It also markets oxidation catalysts for vinyl acetate production.

  7. Expanding Human Cognition and Communication

    SciTech Connect

    Spohrer, Jim; Pierce, Brian M.; Murray, Cherry A.; Golledge, Reginald G.; Horn, Robert E.; Turkle, Sherry; Yonas, Gerold; Glicken Turnley, Jessica; Pollack, Jordan; Burger, Rudy; Robinett, Warren; Wilson, Larry Todd; Bainbridge, W. S.; Canton, J.; Kuekes, P.; Loomis, J.; Penz, P.

    2013-01-01

    To be able to chart the most profitable future directions for societal transformation and corresponding scientific research, five multidisciplinary themes focused on major goals have been identified to fulfill the overall motivating vision of convergence described in the previous pages. The first, “Expanding Human Cognition and Communication,” is devoted to technological breakthroughs that have the potential to enhance individuals’ mental and interaction abilities. Throughout the twentieth century, a number of purely psychological techniques were offered for strengthening human character and personality, but evaluation research has generally failed to confirm the alleged benefits of these methods (Druckman and Bjork 1992; 1994). Today, there is good reason to believe that a combination of methods, drawing upon varied branches of converging science and technology, would be more effective than attempts that rely upon mental training alone.

  8. (Advanced accelerator physics featuring the problems of small rings)

    SciTech Connect

    Olsen, D.K.

    1989-10-16

    The traveler attended the CERN Accelerator School and Uppsala University short course on Advanced Accelerator Physics held on the University campus, Uppsala, Sweden, from September 18-29, 1989. The course, attended by 81 people, was well conceived, well presented, and informative. The course was organized and specialized on the problems of small rings. The traveler also visited the CELSIUS ring facility of Uppsala University and the CRYRING ring facility of the Manne Siegbahn Institute in Stockholm, Sweden.

  9. R&D PROPOSAL FOR THE NATIONAL MUON ACCELERATOR PROGRAM

    SciTech Connect

    Muon Accelerator Program; Zisman, Michael S.; Geer, Stephen

    2010-02-24

    This document contains a description of a multi-year national R&D program aimed at completing a Design Feasibility Study (DFS) for a Muon Collider and, with international participation, a Reference Design Report (RDR) for a muon-based Neutrino Factory. It also includes the supporting component development and experimental efforts that will inform the design studies and permit an initial down-selection of candidate technologies for the ionization cooling and acceleration systems. We intend to carry out this plan with participants from the host national laboratory (Fermilab), those from collaborating U.S. national laboratories (ANL, BNL, Jlab, LBNL, and SNAL), and those from a number of other U.S. laboratories, universities, and SBIR companies. The R&D program that we propose will provide the HEP community with detailed information on future facilities based on intense beams of muons--the Muon Collider and the Neutrino Factory. We believe that these facilities offer the promise of extraordinary physics capabilities. The Muon Collider presents a powerful option to explore the energy frontier and the Neutrino Factory gives the opportunity to perform the most sensitive neutrino oscillation experiments possible, while also opening expanded avenues for the study of new physics in the neutrino sector. The synergy between the two facilities presents the opportunity for an extremely broad physics program and a unique pathway in accelerator facilities. Our work will give clear answers to the questions of expected capabilities and performance of these muon-based facilities, and will provide defensible ranges for their cost. This information, together with the physics insights gained from the next-generation neutrino and LHC experiments, will allow the HEP community to make well-informed decisions regarding the optimal choice of new facilities. We believe that this work is a critical part of any broad strategic program in accelerator R&D and, as the P5 panel has recently

  10. Laser Induced Fluorescence Studies of Electrostatic Double Layers in an Expanding Helicon Plasma

    NASA Astrophysics Data System (ADS)

    Carr, Jerry, Jr.

    We report the first evidence of a laboratory double layer (DL) collapsing in the presence of an instability studied by Chakraborty Thakur et al. 1 with the use of time resolved laser induced fluorescence (LIF) studies. Higher time resolution studies then provided the first statistically validated proof of the correlation between the ion acoustic instability and a DL. Time-frequency analysis in the form of time resolved cross power spectra and continuous wavelet transforms were used to provide insight into beam formation. The implications of this work is that in the creation of strong DLs in expanding plasmas for plasma propulsion or other applications may be self-limited through instability growth. Over the past decade, experimental and theoretical studies have demonstrated the formation of stable, electrostatic, current-free double layers (CFDLs) in plasmas with a strong density gradient; typically a result of a divergent magnetic field. In this work, we present evidence for the formation of multiple double layers within a single divergent magnetic field structure. Downstream of the divergent magnetic field, multiple accelerated ion populations are observed through laser induced fluorescence measurements of the ion velocity distribution function. The formation of the multiple double layer structure is a strong function of the neutral gas pressure in the experiment. The similarity of the accelerated ion populations observed in these laboratory experiments to ion populations observed in reconnection outflow regions in the magnetosphere and in numerical simulations is also described. If ion energization during magnetic reconnection also results solely from acceleration in electric fields, these observations imply a prediction that the ion heating, i.e., the broadening of ion velocity distribution functions, reported in magnetic reconnection experiments is more accurately described by a superposition of differently accelerated ion populations. Therefore, the ion

  11. Brane f(R) gravity and the dark side of the universe

    SciTech Connect

    Borzou, A.; Sepangi, H. R.; Shahidi, S.; Yousefi, R.

    2009-10-27

    We consider a brane world scenario in which the bulk action is assumed to have the form of a generic function of the Ricci scalar f(R) and derive the resulting Einstein field equation on the brane. In a constant curvature bulk a conserved geometric quantity appears in the field equations which can be associated with matter. We present spherically symmetric solutions which account for galaxy rotation curves in a specific form. Then cosmological solutions by assuming a specific form for f(R) are derived which can explain an accelerated expanding universe.

  12. Princeton Expands Family-Friendly Benefits for Graduate Students with Children

    ERIC Educational Resources Information Center

    Millman, Sierra

    2007-01-01

    Princeton University has expanded a package of family-friendly benefits for graduate students that is designed to encourage more women to pursue careers in higher education. Joan S. Girgus, special assistant on diversity to the dean of the faculty, states that the university tried to think more comprehensively about what was needed. In an effort…

  13. Production of biodiesel using expanded gas solvents

    SciTech Connect

    Ginosar, Daniel M; Fox, Robert V; Petkovic, Lucia M

    2009-04-07

    A method of producing an alkyl ester. The method comprises providing an alcohol and a triglyceride or fatty acid. An expanding gas is dissolved into the alcohol to form a gas expanded solvent. The alcohol is reacted with the triglyceride or fatty acid in a single phase to produce the alkyl ester. The expanding gas may be a nonpolar expanding gas, such as carbon dioxide, methane, ethane, propane, butane, pentane, ethylene, propylene, butylene, pentene, isomers thereof, and mixtures thereof, which is dissolved into the alcohol. The gas expanded solvent may be maintained at a temperature below, at, or above a critical temperature of the expanding gas and at a pressure below, at, or above a critical pressure of the expanding gas.

  14. Polarized proton acceleration program at the AGS

    SciTech Connect

    Lee, Y.Y.

    1981-01-01

    The unexpected importance of high energy spin effects and the success of the ZGS in correcting many intrinsic and imperfection depolarizing resonances led us to attempt to accelerate polarized protons in the AGS. A multi-university/laboratory collaborative effort involving Argonne, Brookhaven, Michigan, Rice and Yale is underway to improve and modify to accelerate polarized protons. From the experience at the ZGS and careful studies made us confident of the feasibility of achieving a polarization of over 60 percent up to 26 GeV/c with an intensity of 10/sup 11/ approx. 10/sup 12/ per pulse. The first polarized proton acceleration at the AGS is expected in 1983.

  15. Muon Collider Progress: Accelerators

    SciTech Connect

    Zisman, Michael S.

    2011-09-10

    A muon collider would be a powerful tool for exploring the energy-frontier with leptons, and would complement the studies now under way at the LHC. Such a device would offer several important benefits. Muons, like electrons, are point particles so the full center-of-mass energy is available for particle production. Moreover, on account of their higher mass, muons give rise to very little synchrotron radiation and produce very little beamstrahlung. The first feature permits the use of a circular collider that can make efficient use of the expensive rf system and whose footprint is compatible with an existing laboratory site. The second feature leads to a relatively narrow energy spread at the collision point. Designing an accelerator complex for a muon collider is a challenging task. Firstly, the muons are produced as a tertiary beam, so a high-power proton beam and a target that can withstand it are needed to provide the required luminosity of ~1 × 10{sup 34} cm{sup –2}s{sup –1}. Secondly, the beam is initially produced with a large 6D phase space, which necessitates a scheme for reducing the muon beam emittance (“cooling”). Finally, the muon has a short lifetime so all beam manipulations must be done very rapidly. The Muon Accelerator Program, led by Fermilab and including a number of U.S. national laboratories and universities, has undertaken design and R&D activities aimed toward the eventual construction of a muon collider. Design features of such a facility and the supporting R&D program are described.

  16. Model of An Expanding Heliosphere

    NASA Astrophysics Data System (ADS)

    Song, P.; Vasyliunas, V. M.

    2015-12-01

    Conventional models of the heliosphere assume that the heliopause is formed, similarly to the magnetopause of a planet, at the location where the total pressure of the exterior (interstellar) medium is balanced by the total pressure of the interior (heliospheric) medium. The heliosphere, however, differs greatly from a planetary magnetosphere in being dominated by a continuous interior source of mass (present in some planetary magnetospheres, notably Jupiter and Saturn, but not to anything like the same extent), and it differs as well from systems with large interior mass sources such as comets (to which it has also been compared) in being threaded by magnetic flux from its central object (the Sun). The heliosphere must thus expand continually as more and more mass is put into it by the solar wind, with the heliopause marching into the interstellar medium at some non-zero speed while maintaining the plasma total (thermal plus magnetic) pressure equal to that of the interstellar medium. A steady state heliosphere is, strictly speaking, impossible unless and until the distinction between the heliospheric and the interstellar medium has disappeared. The geometry of the expansion can be visualized in different ways. Conventionally it is taken for granted that the expansion is deflected by interstellar flow sideways and channeled into an extended wake/tail region, the rest of the heliosphere being in apparently steady state. Even if this may occur, it would be at a distance much larger than commonly assumed. We explore the alternative possibility of a heliosphere expanding predominantly in the radial direction and describe some of its properties. The input from solar wind and interplanetary magnetic field during each solar cycle forms a shell, with subsequent cycles adding shells of alternating magnetic polarities. The ultimate extent of the heliosphere (in all directions) and the number of shells can be limited by the time until either the solar output or the

  17. First Universities Allied for Essential Medicines (UAEM) Neglected Diseases and Innovation Symposium

    PubMed Central

    Musselwhite, Laura W.; Maciag, Karolina; Lankowski, Alex; Gretes, Michael C.; Wellems, Thomas E.; Tavera, Gloria; Goulding, Rebecca E.; Guillen, Ethan

    2012-01-01

    Universities Allied for Essential Medicines organized its first Neglected Diseases and Innovation Symposium to address expanding roles of public sector research institutions in innovation in research and development of biomedical technologies for treatment of diseases, particularly neglected tropical diseases. Universities and other public research institutions are increasingly integrated into the pharmaceutical innovation system. Academic entities now routinely undertake robust high-throughput screening and medicinal chemistry research programs to identify lead compounds for small molecule drugs and novel drug targets. Furthermore, product development partnerships are emerging between academic institutions, non-profit entities, and biotechnology and pharmaceutical companies to create diagnostics, therapies, and vaccines for diseases of the poor. With not for profit mission statements, open access publishing standards, open source platforms for data sharing and collaboration, and a shift in focus to more translational research, universities and other public research institutions are well-placed to accelerate development of medical technologies, particularly for neglected tropical diseases. PMID:22232453

  18. [Proton therapy and particle accelerators].

    PubMed

    Fukumoto, Sadayoshi

    2012-01-01

    Since the high energy accelerator plan was changed from a 40 GeV direct machine to a 12GeV cascade one, a 500 MeV rapid cycling booster synchrotron was installed between the injector linac and the 12 GeV main ring at KEK, National Lab. for High Energy Physics. The booster beams were used not only for injection to the main ring but also for medical use. Their energy was reduced to 250 MeV by a graphite block for clinical trial of cancer therapy. In 1970's, pi(-) or heavy ions were supposed to be promising. Although advantage of protons with Bragg Peak was pointed out earlier, they seemed effective only for eye melanoma at that time. In early 1980's, it was shown that they were effective for deep-seated tumor by Tsukuba University with KEK beams. The first dedicated facility was built at Loma Linda University Medical Center. Its synchrotron was made by Fermi National Accelerator Lab. Since a non-resonant accelerating rf cavity was installed, operation of the synchrotron became much easier. Later, innovation of the cyclotron was achieved. Its weight was reduced from 1,000 ton to 200 ton. Some of the cyclotrons are equipped with superconducting coils.

  19. Lasers and new methods of particle acceleration

    SciTech Connect

    Parsa, Z.

    1998-02-01

    There has been a great progress in development of high power laser technology. Harnessing their potential for particle accelerators is a challenge and of great interest for development of future high energy colliders. The author discusses some of the advances and new methods of acceleration including plasma-based accelerators. The exponential increase in sophistication and power of all aspects of accelerator development and operation that has been demonstrated has been remarkable. This success has been driven by the inherent interest to gain new and deeper understanding of the universe around us. With the limitations of the conventional technology it may not be possible to meet the requirements of the future accelerators with demands for higher and higher energies and luminosities. It is believed that using the existing technology one can build a linear collider with about 1 TeV center of mass energy. However, it would be very difficult (or impossible) to build linear colliders with energies much above one or two TeV without a new method of acceleration. Laser driven high gradient accelerators are becoming more realistic and is expected to provide an alternative, (more compact, and more economical), to conventional accelerators in the future. The author discusses some of the new methods of particle acceleration, including laser and particle beam driven plasma based accelerators, near and far field accelerators. He also discusses the enhanced IFEL (Inverse Free Electron Laser) and NAIBEA (Nonlinear Amplification of Inverse-Beamstrahlung Electron Acceleration) schemes, laser driven photo-injector and the high energy physics requirements.

  20. TURBULENT SHEAR ACCELERATION

    SciTech Connect

    Ohira, Yutaka

    2013-04-10

    We consider particle acceleration by large-scale incompressible turbulence with a length scale larger than the particle mean free path. We derive an ensemble-averaged transport equation of energetic charged particles from an extended transport equation that contains the shear acceleration. The ensemble-averaged transport equation describes particle acceleration by incompressible turbulence (turbulent shear acceleration). We find that for Kolmogorov turbulence, the turbulent shear acceleration becomes important on small scales. Moreover, using Monte Carlo simulations, we confirm that the ensemble-averaged transport equation describes the turbulent shear acceleration.

  1. The direction of acceleration

    NASA Astrophysics Data System (ADS)

    Wilhelm, Thomas; Burde, Jan-Philipp; Lück, Stephan

    2015-11-01

    Acceleration is a physical quantity that is difficult to understand and hence its complexity is often erroneously simplified. Many students think of acceleration as equivalent to velocity, a ˜ v. For others, acceleration is a scalar quantity, which describes the change in speed Δ|v| or Δ|v|/Δt (as opposed to the change in velocity). The main difficulty with the concept of acceleration therefore lies in developing a correct understanding of its direction. The free iOS app AccelVisu supports students in acquiring a correct conception of acceleration by showing acceleration arrows directly at moving objects.

  2. Expanding discourse repertoires with hybridity

    NASA Astrophysics Data System (ADS)

    Kelly, Gregory J.

    2012-09-01

    In "Hybrid discourse practice and science learning" Kamberelis and Wehunt present a theoretically rich argument about the potential of hybrid discourses for science learning. These discourses draw from different forms of "talk, social practice, and material practices" to create interactions that are "intertextually complex" and "interactionally dynamic." The hybrid discourse practices are described as involving the dynamic interplay of at least three key elements: "the lamination of multiple cultural frames, the shifting relations between people and their discourse, and the shifting power relations between and among people." Each of these elements requires a respective unit of analysis and are often mutually reinforcing. The authors present a theoretically cogent argument for the study of hybrid discourse practices and identify the potential such discourses may have for science education. This theoretical development leads to an analysis of spoken and written discourse around a set of educational events concerning the investigation of owl pellets by two fifth grade students, their classmates, and teacher. Two discourse segments are presented and analyzed by the authors in detail. The first is a discourse analysis of the dissection of the owl pellet by two students, Kyle and Max. The second analysis examines the science report of these same two students. In this article, I pose a number of questions about the study with the hope that by doing so I expand the conversation around the insightful analysis presented.

  3. Compact Radiometers Expand Climate Knowledge

    NASA Technical Reports Server (NTRS)

    2010-01-01

    To gain a better understanding of Earth's water, energy, and carbon cycles, NASA plans to embark on the Soil Moisture Active and Passive mission in 2015. To prepare, Goddard Space Flight Center provided Small Business Innovation Research (SBIR) funding to ProSensing Inc., of Amherst, Massachusetts, to develop a compact ultrastable radiometer for sea surface salinity and soil moisture mapping. ProSensing incorporated small, low-cost, high-performance elements into just a few circuit boards and now offers two lightweight radiometers commercially. Government research agencies, university research groups, and large corporations around the world are using the devices for mapping soil moisture, ocean salinity, and wind speed.

  4. Mapa-an object oriented code with a graphical user interface for accelerator design and analysis

    SciTech Connect

    Shasharina, Svetlana G.; Cary, John R.

    1997-02-01

    We developed a code for accelerator modeling which will allow users to create and analyze accelerators through a graphical user interface (GUI). The GUI can read an accelerator from files or create it by adding, removing and changing elements. It also creates 4D orbits and lifetime plots. The code includes a set of accelerator elements classes, C++ utility and GUI libraries. Due to the GUI, the code is easy to use and expand.

  5. Mapa-an object oriented code with a graphical user interface for accelerator design and analysis

    SciTech Connect

    Shasharina, S.G.; Cary, J.R.

    1997-02-01

    We developed a code for accelerator modeling which will allow users to create and analyze accelerators through a graphical user interface (GUI). The GUI can read an accelerator from files or create it by adding, removing and changing elements. It also creates 4D orbits and lifetime plots. The code includes a set of accelerator elements classes, C++ utility and GUI libraries. Due to the GUI, the code is easy to use and expand. {copyright} {ital 1997 American Institute of Physics.}

  6. The Radiological Research Accelerator Facility

    SciTech Connect

    Hall, E.J.

    1992-05-01

    The Radiological Research Accelerator Facility (RARAF) is based on a 4-MV Van de Graaff accelerator, which is used to generate a variety of well-characterized radiation beams for research in radiobiology, radiological physics, and radiation chemistry. It is part of the Center for Radiological Research (CRR) -- formerly the Radiological Research Laboratory (RRL) -- of Columbia University, and its operation is supported as a National Facility by the US Department of Energy (DOE). As such, RARAF is available to all potential users on an equal basis, and scientists outside the CRR are encouraged to submit proposals for experiments at RARAF. The operation of the Van de Graaff is supported by the DOE, but the research projects themselves must be supported separately. Experiments performed from May 1991--April 1992 are described.

  7. The Radiological Research Accelerator Facility

    SciTech Connect

    Hall, E.J.; Marino, S.A.

    1993-05-01

    The Radiological Research Accelerator Facility (RARAF) is based on a 4-MV Van de Graaff accelerator, which is used to generate a variety of well-characterized radiation beams for research in radiobiology, radiological physics, and radiation chemistry. It is part of the Center for Radiological Research (CRR) - formerly the Radiological Research Laboratory of Columbia University, and its operation is supported as a National Facility by the US Department of Energy (DOE). As such, RARAF is available to all potential users on an equal basis and scientists outside the CRR are encouraged to submit proposals for experiments at RARAF. The operation of the Van de Graaff is supported by the DOE, but the research projects themselves must be supported separately. This report provides a listing and brief description of experiments performed at RARAF during the May 1, 1992 through April 30, 1993.

  8. Hardware-Accelerated Simulated Radiography

    SciTech Connect

    Laney, D; Callahan, S; Max, N; Silva, C; Langer, S; Frank, R

    2005-08-04

    We present the application of hardware accelerated volume rendering algorithms to the simulation of radiographs as an aid to scientists designing experiments, validating simulation codes, and understanding experimental data. The techniques presented take advantage of 32-bit floating point texture capabilities to obtain solutions to the radiative transport equation for X-rays. The hardware accelerated solutions are accurate enough to enable scientists to explore the experimental design space with greater efficiency than the methods currently in use. An unsorted hexahedron projection algorithm is presented for curvilinear hexahedral meshes that produces simulated radiographs in the absorption-only regime. A sorted tetrahedral projection algorithm is presented that simulates radiographs of emissive materials. We apply the tetrahedral projection algorithm to the simulation of experimental diagnostics for inertial confinement fusion experiments on a laser at the University of Rochester.

  9. Accelerating Particles with Plasma

    SciTech Connect

    Litos, Michael; Hogan, Mark

    2014-11-05

    Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to very high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

  10. Accelerator Technology Division

    NASA Astrophysics Data System (ADS)

    1992-04-01

    In fiscal year (FY) 1991, the Accelerator Technology (AT) division continued fulfilling its mission to pursue accelerator science and technology and to develop new accelerator concepts for application to research, defense, energy, industry, and other areas of national interest. This report discusses the following programs: The Ground Test Accelerator Program; APLE Free-Electron Laser Program; Accelerator Transmutation of Waste; JAERI, OMEGA Project, and Intense Neutron Source for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Super Collider; The High-Power Microwave Program; (Phi) Factory Collaboration; Neutral Particle Beam Power System Highlights; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations.

  11. Linear accelerator: A concept

    NASA Technical Reports Server (NTRS)

    Mutzberg, J.

    1972-01-01

    Design is proposed for inexpensive accelerometer which would work by applying pressure to fluid during acceleration. Pressure is used to move shuttle, and shuttle movement is sensed and calibrated to give acceleration readings.

  12. Improved plasma accelerator

    NASA Technical Reports Server (NTRS)

    Cheng, D. Y.

    1971-01-01

    Converging, coaxial accelerator electrode configuration operates in vacuum as plasma gun. Plasma forms by periodic injections of high pressure gas that is ionized by electrical discharges. Deflagration mode of discharge provides acceleration, and converging contours of plasma gun provide focusing.

  13. Evolution of the universe

    NASA Astrophysics Data System (ADS)

    Novikov, I. D.

    The underlying principles and discoveries of cosmology are presented in a qualitative form. The General Theory of Relativity is the basis for the science of the structure of the Universe, and Friedmann in 1922-4 demonstrated that the Universe is either expanding or contracting; Hubble in 1929 provided evidence for expansion. The physical processes of the evolution of the Universe to date have been projected to include origins in a superdense, superhot state with violent reactions between elementary particles. The resulting matter fragmented into the stellar systems and agglomerations presently observed. Observational data of the most distant galaxies now covers a range of 10 Gpc. Current studies focus on the missing matter in the Universe and the mean density of matter, the gravitation of vacuum, relict radiation from the Big Bang, the curvature of space-time, and theories for the earliest moments of the Universe, including pancake theories, the synthesis of light elements, and black and white holes.

  14. FPIA helps expand contraceptive services.

    PubMed

    Groot, H

    1984-01-01

    Since the beginning in 1971 of the Planned Parenthood Federation of America's international program, Family Planning International Assistance (FPIA), US$54 million has been contributed in direct financial support for the operation of over 300 family planning programs in 51 countries; over 3000 institutions in 115 countries have been supplied with family planning commodities, including over 600 million condoms, 120 cycles of oral contraceptives, and 4 million IUD; and about 1 million contraceptive clients were served by FPIA funded projects in 1982 aone. Since 1971, however, the world's population has increased from 3.7 billion to around 4.7 billion people. About 85 million people are added to the world each year. There is consensus that without organized family planning programs, today's world population would be even higher. FPIA measures its progress in terms of expanding the availability of contraceptive services in devloping countries. FPIA supported projects have helped make services available in areas previously lacking them, and has helped involve a wide variety of organizations, such as women's groups, youth organizations, and Red Cross Societies, in family planning services. A prime concern of FPIA, which has limited resources, is what happens to projects once FPIA support is terminated. FPIA has been paying attention to local income generation to help projects become more self-supporting and to increas staff members' management skills. The more successful income-generating schemes appear to be directly related to family planning, selling contraceptives and locally produced educational materials, and charging fees for family planning and related medical services and tuition for training courses. FPIA funded to projects use management by objectives (MBO) to help improve management skills. MBO helps grantees improve their ability to set objectives, plan, monitor, report, and do day-to-day project management.

  15. Improving and expanding NGO programmes.

    PubMed

    Mukhopadhyay, A

    1993-06-01

    India has massive problems and is in need of improving and expanding non governmental organization (NGO) programs by broadening the scope of NGO activities, identifying successful NGO activities, and by moving closer to the community to participate in their activities. The problems and experience in the last few decades indicate that with expansion bureaucratization takes place. The institution begins to depend on donors and follows donor-driven agendas. As more money is given by the government, many more so called GONGO or Government-NGO projects materialize. Another problem is that the government almost always approaches the NGOs for the implementation of a project, and there is complete lack of cooperation at the planning stage. The government is considering a loan from the World Bank and UNICEF to launch a mother and child health program, but there has not been any discussion with the dozens of people who have worked on issues concerning mother and child health issues for many years. There is a need to be more demanding of the government about the various programs that are implemented for the government. Very few NGO health and family welfare projects are run by ordinary nurses or ordinary Ayurvedic doctors under ordinary conditions. Since successful NGO work has to be extended to other parts of the country, they will have to be run by ordinary people with very ordinary resources. Over the years, the NGO community has become preoccupied with its own agenda. Today, despite very sophisticated equipment and infrastructure, they are not able to reach the 60,000-70,000 workers and employees. Some of the ideas with respect to the strengthens and weaknesses of community participation have to be shared. NGOs should include all the existing non governmental organizations throughout the country, and have a dialogue with other nongovernmental bodies such as trade unions. The challenge is to adjust the current agenda, prevailing style, and present way of operating and move

  16. MEQALAC rf accelerating structure

    SciTech Connect

    Keane, J.; Brodowski, J.

    1981-01-01

    A prototype MEQALAC capable of replacing the Cockcroft Walton pre-injector at BNL is being fabricated. Ten milliamperes of H/sup -/ beam supplied from a source sitting at a potential of -40 kilovolt is to be accelerated to 750 keV. This energy gain is provided by a 200 Megahertz accelerating system rather than the normal dc acceleration. Substantial size and cost reduction would be realized by such a system over conventional pre-accelerator systems.

  17. The deuteron accelerator preliminary design for BISOL

    NASA Astrophysics Data System (ADS)

    Peng, S. X.; Zhu, F.; Wang, Z.; Gao, Y.; Guo, Z. Y.

    2016-06-01

    BISOL, which was named as Beijing_ISOL before (Cui et al., 2013), is the abbreviation of Beijing Isotope-Separation-On-Line neutron beam facility. It is proposed jointly by Peking University (PKU) and China Institute of Atomic Energy (CIAE) for basic science study and application. It is a double driven facility that can be driven by a reactor or a deuteron accelerator. The deuteron driver accelerator should accelerate the deuteron beam up to 40 MeV with maximum beam current of 10 mA. Proton beams up to 33 MeV and He2+ beams up to 81.2 MeV can also be accelerated in this accelerator. The accelerator can be operated on either CW (continuous waveform) or pulsed mode, and the ion energy can be adjusted in a wide range. The accelerator will also allow independent operation of the RIB (Radioactive Ion Beams) system. It will be mainly charged by PKU group. Details of the deuteron accelerator preliminary design for BISOL will be given in this paper.

  18. Acceleration gradient of a plasma wakefield accelerator

    SciTech Connect

    Uhm, Han S.

    2008-02-25

    The phase velocity of the wakefield waves is identical to the electron beam velocity. A theoretical analysis indicates that the acceleration gradient of the wakefield accelerator normalized by the wave breaking amplitude is K{sub 0}({xi})/K{sub 1}({xi}), where K{sub 0}({xi}) and K{sub 1}({xi}) are the modified Bessel functions of the second kind of order zero and one, respectively and {xi} is the beam parameter representing the beam intensity. It is also shown that the beam density must be considerably higher than the diffuse plasma density for the large radial velocity of plasma electrons that are required for a high acceleration gradient.

  19. Acceleration: It's Elementary

    ERIC Educational Resources Information Center

    Willis, Mariam

    2012-01-01

    Acceleration is one tool for providing high-ability students the opportunity to learn something new every day. Some people talk about acceleration as taking a student out of step. In actuality, what one is doing is putting a student in step with the right curriculum. Whole-grade acceleration, also called grade-skipping, usually happens between…

  20. Far field acceleration

    SciTech Connect

    Fernow, R.C.

    1995-07-01

    Far fields are propagating electromagnetic waves far from their source, boundary surfaces, and free charges. The general principles governing the acceleration of charged particles by far fields are reviewed. A survey of proposed field configurations is given. The two most important schemes, Inverse Cerenkov acceleration and Inverse free electron laser acceleration, are discussed in detail.

  1. Angular Acceleration without Torque?

    ERIC Educational Resources Information Center

    Kaufman, Richard D.

    2012-01-01

    Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

  2. Advantages and Challenges of Superconducting Accelerators

    NASA Astrophysics Data System (ADS)

    Krischel, Detlef

    After a short review of the history toward high-energy superconducting (SC) accelerators for ion beam therapy (IBT), an overview is given on material properties and technical developments enabling to use SC components in a medical accelerator for full body cancer treatment. The design concept and the assembly of a commercially available SC cyclotron for proton therapy (PT) are described and the potential advantages for applying superconductivity are assessed. The discussion includes the first years of operation experience with regard to cryogenic and magnetic performance, automated beam control, and maintenance aspects. An outlook is given on alternative machine concepts for protons-only or for heavier ions. Finally, it is discussed whether the application of superconductivity might be expanded in the future to a broader range of subsystems of clinical IBT accelerators such as SC magnets for transfer beam lines or gantries.

  3. Extinction events can accelerate evolution.

    PubMed

    Lehman, Joel; Miikkulainen, Risto

    2015-01-01

    Extinction events impact the trajectory of biological evolution significantly. They are often viewed as upheavals to the evolutionary process. In contrast, this paper supports the hypothesis that although they are unpredictably destructive, extinction events may in the long term accelerate evolution by increasing evolvability. In particular, if extinction events extinguish indiscriminately many ways of life, indirectly they may select for the ability to expand rapidly through vacated niches. Lineages with such an ability are more likely to persist through multiple extinctions. Lending computational support for this hypothesis, this paper shows how increased evolvability will result from simulated extinction events in two computational models of evolved behavior. The conclusion is that although they are destructive in the short term, extinction events may make evolution more prolific in the long term.

  4. Extinction Events Can Accelerate Evolution

    PubMed Central

    Lehman, Joel; Miikkulainen, Risto

    2015-01-01

    Extinction events impact the trajectory of biological evolution significantly. They are often viewed as upheavals to the evolutionary process. In contrast, this paper supports the hypothesis that although they are unpredictably destructive, extinction events may in the long term accelerate evolution by increasing evolvability. In particular, if extinction events extinguish indiscriminately many ways of life, indirectly they may select for the ability to expand rapidly through vacated niches. Lineages with such an ability are more likely to persist through multiple extinctions. Lending computational support for this hypothesis, this paper shows how increased evolvability will result from simulated extinction events in two computational models of evolved behavior. The conclusion is that although they are destructive in the short term, extinction events may make evolution more prolific in the long term. PMID:26266804

  5. Accelerators for heavy ion fusion

    SciTech Connect

    Bangerter, R.O.

    1985-10-01

    Large fusion devices will almost certainly produce net energy. However, a successful commercial fusion energy system must also satisfy important engineering and economic constraints. Inertial confinement fusion power plants driven by multi-stage, heavy-ion accelerators appear capable of meeting these constraints. The reasons behind this promising outlook for heavy-ion fusion are given in this report. This report is based on the transcript of a talk presented at the Symposium on Lasers and Particle Beams for Fusion and Strategic Defense at the University of Rochester on April 17-19, 1985.

  6. WIPO Re:Search: Accelerating anthelmintic development through cross-sector partnerships

    PubMed Central

    Ramamoorthi, Roopa; Graef, Katy M.; Dent, Jennifer

    2014-01-01

    Neglected tropical diseases (NTDs), malaria, and tuberculosis have a devastating effect on an estimated 1.6 billion people worldwide. The World Intellectual Property Organization (WIPO) Re:Search consortium accelerates the development of new drugs, vaccines, and diagnostics for these diseases by connecting the assets and resources of pharmaceutical companies, such as compound libraries and expertise, to academic or nonprofit researchers with novel product discovery or development ideas. As the WIPO Re:Search Partnership Hub Administrator, BIO Ventures for Global Health (BVGH) fields requests from researchers, identifies Member organizations able to fulfill these requests, and helps forge mutually beneficial collaborations. Since its inception in October 2011, WIPO Re:Search membership has expanded to more than 90 institutions, including leading pharmaceutical companies, universities, nonprofit research institutions, and product development partnerships from around the world. To date, WIPO Re:Search has facilitated over 70 research agreements between Consortium Members, including 11 collaborations focused on anthelmintic drug discovery. PMID:25516832

  7. University Literacy: A Multi-Literacies Model

    ERIC Educational Resources Information Center

    Miller, Andrew; Schulz, Samantha

    2014-01-01

    Literacy teachers in schools and universities share a common goal: to prepare students with the "literacies" they need to succeed in and beyond educational settings. In a "widening-participation" era universities must increase and expand their literacy offerings to help students make the most of their university experiences. At…

  8. Compact Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Foster, John E.

    2004-01-01

    A plasma accelerator has been conceived for both material-processing and spacecraft-propulsion applications. This accelerator generates and accelerates ions within a very small volume. Because of its compactness, this accelerator could be nearly ideal for primary or station-keeping propulsion for spacecraft having masses between 1 and 20 kg. Because this accelerator is designed to generate beams of ions having energies between 50 and 200 eV, it could also be used for surface modification or activation of thin films.

  9. AstroCom NYC: Expanding the Partnership

    NASA Astrophysics Data System (ADS)

    Paglione, Timothy; Ford, Saavik; Agueros, Marcel A.; Mac Low, Mordecai-Mark; Robbins, Dennis

    2015-01-01

    AstroCom NYC is an undergraduate mentoring program designed to improve urban minority student access to opportunities in astrophysical research by greatly enhancing partnerships between research astronomers in New York City (City University of New York - an MSI, American Museum of Natural History, and Columbia). AstroCom NYC provides centralized, personalized mentoring as well as financial and academic support, to CUNY undergraduates throughout their studies, plus the resources and opportunities to further CUNY faculty research with students. The goal is that students' residency at AMNH helps them build a sense of belonging in the field, and readies and inspires them for graduate study. AstroCom NYC provides a rigorous Methods of Scientific Research course developed specifically to this purpose, a laptop, research and career mentors, outreach activities, scholarships and stipends, Metrocards, and regular assessment for maximum effectiveness. Stipends in part alleviate the burdens at home typical for CUNY students so they may concentrate on their academic success. AMNH serves as the central hub for our faculty and students, who are otherwise dispersed among all five boroughs of the City. For our second cohort, we dramatically improved the application and screening process, implemented a number of tools to evaluate their potential for grad school, and began growing a network of potential hosts for summer internships around NY State and the US. We review these implementations and outcomes, as well as plans for Year 3, when we expect many of our current students to compete for external summer REUs, and after greatly expanding the program reach through a NASA community college initiative.

  10. High brightness electron accelerator

    DOEpatents

    Sheffield, Richard L.; Carlsten, Bruce E.; Young, Lloyd M.

    1994-01-01

    A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of acclerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electons as the electrons enter the first cavity.

  11. Fiber Accelerating Structures

    SciTech Connect

    Hammond, Andrew P.; /Reed Coll. /SLAC

    2010-08-25

    One of the options for future particle accelerators are photonic band gap (PBG) fiber accelerators. PBG fibers are specially designed optical fibers that use lasers to excite an electric field that is used to accelerate electrons. To improve PBG accelerators, the basic parameters of the fiber were tested to maximize defect size and acceleration. Using the program CUDOS, several accelerating modes were found that maximized these parameters for several wavelengths. The design of multiple defects, similar to having closely bound fibers, was studied to find possible coupling or the change of modes. The amount of coupling was found to be dependent on distance separated. For certain distances accelerating coupled modes were found and examined. In addition, several non-periodic fiber structures were examined using CUDOS. The non-periodic fibers produced several interesting results and promised more modes given time to study them in more detail.

  12. Seventy Five Years of Particle Accelerators

    SciTech Connect

    Andy Sessler

    2008-04-04

    Andy Sessler, Berkeley Lab director from 1973 to 1980, sheds light on the Lab's nearly eight-decade history of inventing and refining particle accelerators, which continue to illuminate the nature of the universe. His talk was presented July 26, 2006.

  13. Seventy Five Years of Particle Accelerators

    ScienceCinema

    Andy Sessler

    2016-07-12

    Andy Sessler, Berkeley Lab director from 1973 to 1980, sheds light on the Lab's nearly eight-decade history of inventing and refining particle accelerators, which continue to illuminate the nature of the universe. His talk was presented July 26, 2006.

  14. Probing gravitation, dark energy, and acceleration

    SciTech Connect

    Linder, Eric V.

    2004-02-20

    The acceleration of the expansion of the universe arises from unknown physical processes involving either new fields in high energy physics or modifications of gravitation theory. It is crucial for our understanding to characterize the properties of the dark energy or gravity through cosmological observations and compare and distinguish between them. In fact, close consistencies exist between a dark energy equation of state function w(z) and changes to the framework of the Friedmann cosmological equations as well as direct spacetime geometry quantities involving the acceleration, such as ''geometric dark energy'' from the Ricci scalar. We investigate these interrelationships, including for the case of super acceleration or phantom energy where the fate of the universe may be more gentle than the Big Rip.

  15. [Traditions of university studies at Kaunas University of Medicine].

    PubMed

    Bruneviciūte, Raimonda; Brazdzionyte, Julija

    2006-01-01

    The aim of this article is to highlight the dimensions of the traditions of the idea of the university that are relevant in our today's world--the autonomy of the university, education of a free and creative personality, and belonging to the unified space of studies--and to review the experience of Kaunas University of Medicine in the development of the traditions of university studies. The research object was university studies, and the methods applied in this research were analysis of literature and analysis of documents. The article consists of the introduction, two parts, and generalization. The first part discusses the autonomy of the university, the importance of liberal studies, and the influence of the European higher education and provides a generalized survey of the historical tradition of university studies in Lithuania. The second part of the article reviews the predominant factors that condition the development of university studies at Kaunas University of Medicine: organization of studies and implementation of liberal studies realized through general university education subjects into the modern content of university studies. The generalization of the results of the performed analysis allows for stating that the contents and the organization of curricula and the ongoing reforms at Kaunas University of Medicine expand the continuity of the traditions of the European university education, highlight the idea of the university, and realize university studies that reflect modern global tendencies. PMID:17090986

  16. Expanding your horizons in science and mathematics

    NASA Technical Reports Server (NTRS)

    Palmer, Cynthia E. A.

    1995-01-01

    The purpose of the 'Expanding Your Horizons in Science and Mathematics' program is to interest young women in grades six through twelve in a variety of careers where mathematics and science are important. Progress in encouraging young women to take courses in mathematics, science, and technological subjects is discussed. Also included are adult, student, and organizational information packets used for 'Expanding Your Horizons' conferences.

  17. Seventy Five Years of Particle Accelerators (LBNL Summer Lecture Series)

    ScienceCinema

    Sessler, Andy

    2016-07-12

    Summer Lecture Series 2006: Andy Sessler, Berkeley Lab director from 1973 to 1980, sheds light on the Lab's nearly eight-decade history of inventing and refining particle accelerators, which continue to illuminate the nature of the universe.

  18. Screw expander for light duty diesel engines

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Preliminary selection and sizing of a positive displacement screw compressor-expander subsystem for a light-duty adiabatic diesel engine; development of a mathematical model to describe overall efficiencies for the screw compressor and expander; simulation of operation to establish overall efficiency for a range of design parameters and at given engine operating points; simulation to establish potential net power output at light-duty diesel operating points; analytical determination of mass moments of inertia for the rotors and inertia of the compressor-expander subsystem; and preparation of engineering layout drawings of the compressor and expander are discussed. As a result of this work, it was concluded that the screw compressor and expander designed for light-duty diesel engine applications are viable alternatives to turbo-compound systems, with acceptable efficiencies for both units, and only a moderate effect on the transient response.

  19. Physics and Accelerator Applications of RF Superconductivity

    SciTech Connect

    H. Padamsee; K. W. Shepard; Ron Sundelin

    1993-12-01

    A key component of any particle accelerator is the device that imparts energy gain to the charged particle. This is usually an electromagnetic cavity resonating at a microwave frequency, chosen between 100 and 3000 MHz. Serious attempts to utilize superconductors for accelerating cavities were initiated more than 25 years ago with the acceleration of electrons in a lead-plated resonator at Stanford University (1). The first full-scale accelerator, the Stanford SCA, was completed in 1978 at the High Energy Physics Laboratory (HEPL) (2). Over the intervening one and a half decades, superconducting cavities have become increasingly important to particle accelerators for nuclear physics and high energy physics. For continuous operation, as is required for many applications, the power dissipation in the walls of a copper structure is quite substantial, for example, 0.1 megawatts per meter of structure operating at an accelerating field of 1 million volts/meter (MV/m). since losses increase as the square of the accelerating field, copper cavities become severely uneconomical as demand for higher fields grows with the higher energies called for by experimenters to probe ever deeper into the structure of matter. Rf superconductivity has become an important technology for particle accelerators. Practical structures with attractive performance levels have been developed for a variety of applications, installed in the targeted accelerators, and operated over significant lengths of time. Substantial progress has been made in understanding field and Q limitations and in inventing cures to advance performance. The technical and economical potential of rf superconductivity makes it an important candidate for future advanced accelerators for free electron lasers, for nuclear physics, and for high energy physics, at the luminosity as well as at the energy frontiers.

  20. Educating and Training Accelerator Scientists and Technologists for Tomorrow

    NASA Astrophysics Data System (ADS)

    Barletta, William; Chattopadhyay, Swapan; Seryi, Andrei

    2012-01-01

    Accelerator science and technology is inherently an integrative discipline that combines aspects of physics, computational science, electrical and mechanical engineering. As few universities offer full academic programs, the education of accelerator physicists and engineers for the future has primarily relied on a combination of on-the-job training supplemented with intensive courses at regional accelerator schools. This article describes the approaches being used to satisfy the educational curiosity of a growing number of interested physicists and engineers.

  1. Educating and Training Accelerator Scientists and Technologists for Tomorrow

    SciTech Connect

    Barletta, William A.; Chattopadhyay, Swapan; Seryi, Andrei

    2012-07-01

    Accelerator science and technology is inherently an integrative discipline that combines aspects of physics, computational science, electrical and mechanical engineering. As few universities offer full academic programs, the education of accelerator physicists and engineers for the future has primarily relied on a combination of on-the-job training supplemented with intense courses at regional accelerator schools. This paper describes the approaches being used to satisfy the educational interests of a growing number of interested physicists and engineers.

  2. Beam Position Monitoring in the CSU Accelerator Facility

    NASA Astrophysics Data System (ADS)

    Einstein, Joshua; Vankeuren, Max; Watras, Stephen

    2014-03-01

    A Beam Position Monitoring (BPM) system is an integral part of an accelerator beamline, and modern accelerators can take advantage of newer technologies and designs when creating a BPM system. The Colorado State University (CSU) Accelerator Facility will include four stripline detectors mounted around the beamline, a low-noise analog front-end, and digitization and interface circuitry. The design will support a sampling rate greater than 10 Hz and sub-100 μm accuracy.

  3. Vibrational Energy Transfer of Diatomic Gases in Hypersonic Expanding Flows.

    NASA Astrophysics Data System (ADS)

    Ruffin, Stephen Merrick

    In high temperature flows related to vehicles at hypersonic speeds significant excitation of the vibrational energy modes of the gas can occur. Accurate predictions of the vibrational state of the gas and the rates of vibrational energy transfer are essential to achieve optimum engine performance, for design of heat shields, and for studies of ground based hypersonic test facilities. The Landau -Teller relaxation model is widely used because it has been shown to give accurate predictions in vibrationally heating flows such as behind forebody shocks. However, a number of experiments in nozzles have indicated that it fails to accurately predict the rate of energy transfer in expanding, or cooling, flow regions and fails to predict the distribution of energy in the vibrational quantum levels. The present study examines the range of applicability of the Landau -Teller model in expanding flows and develops techniques which provide accurate predictions in expanding flows. In the present study, detailed calculations of the vibrational relaxation process of N_2 and CO in cooling flows are conducted. A coupled set of vibrational transition rate equations and quasi one-dimensional fluid dynamic equations is solved. Rapid anharmonic Vibration-Translation transition rates and Vibration -Vibration exchange collisions are found to be responsible for vibrational relaxation acceleration in situations of high vibrational temperature and low translational temperature. The predictions of the detailed master equation solver are in excellent agreement with experimental results. The exact degree of acceleration is cataloged in this study for N_2 and is found to be a function of both the translational temperature (T) and the ratio of vibrational to translational temperatures (T_{vib}/T). Non-Boltzmann population distributions are observed for values of T _{vib}/T as low as 2.0. The local energy transfer rate is shown to be an order of magnitude or more faster than the Landau-Teller model

  4. Analyzing Collision Processes with the Smartphone Acceleration Sensor

    ERIC Educational Resources Information Center

    Vogt, Patrik; Kuhn, Jochen

    2014-01-01

    It has been illustrated several times how the built-in acceleration sensors of smartphones can be used gainfully for quantitative experiments in school and university settings (see the overview in Ref. 1 ). The physical issues in that case are manifold and apply, for example, to free fall, radial acceleration, several pendula, or the exploitation…

  5. Self-accelerating Warped Braneworlds

    SciTech Connect

    Carena, Marcela; Lykken, Joseph; Park, Minjoon; Santiago, Jose; /Fermilab

    2006-11-01

    Braneworld models with induced gravity have the potential to replace dark energy as the explanation for the current accelerating expansion of the Universe. The original model of Dvali, Gabadadze and Porrati (DGP) demonstrated the existence of a ''self-accelerating'' branch of background solutions, but suffered from the presence of ghosts. We present a new large class of braneworld models which generalize the DGP model. Our models have negative curvature in the bulk, allow a second brane, and have general brane tensions and localized curvature terms. We exhibit three different kinds of ghosts, associated to the graviton zero mode, the radion, and the longitudinal components of massive graviton modes. The latter two species occur in the DGP model, for negative and positive brane tension respectively. In our models, we find that the two kinds of DGP ghosts are tightly correlated with each other, but are not always linked to the feature of self-acceleration. Our models are a promising laboratory for understanding the origins and physical meaning of braneworld ghosts, and perhaps for eliminating them altogether.

  6. Self-accelerating warped braneworlds

    SciTech Connect

    Carena, Marcela; Lykken, Joseph; Santiago, Jose; Park, Minjoon

    2007-01-15

    Braneworld models with induced gravity have the potential to replace dark energy as the explanation for the current accelerating expansion of the Universe. The original model of Dvali, Gabadadze, and Porrati (DGP) demonstrated the existence of a 'self-accelerating' branch of background solutions, but suffered from the presence of ghosts. We present a new large class of braneworld models which generalize the DGP model. Our models have negative curvature in the bulk, allow a second brane, and have general brane tensions and localized curvature terms. We exhibit three different kinds of ghosts, associated to the graviton zero mode, the radion, and the longitudinal components of massive graviton modes. The latter two species occur in the DGP model, for negative and positive brane tension, respectively. In our models, we find that the two kinds of DGP ghosts are tightly correlated with each other, but are not always linked to the feature of self-acceleration. Our models are a promising laboratory for understanding the origins and physical meaning of braneworld ghosts, and perhaps for eliminating them altogether.

  7. Time to Grow: Year Two Report on ExpandED Schools. A TASC Report

    ERIC Educational Resources Information Center

    Traill, Saskia; Brohawn, Katie

    2014-01-01

    An analysis of data from the second year of The After-School Corporation's (TASC's) national demonstration of an expanded school day for elementary and middle school students shows that ExpandED Schools improved school culture, decreased rates of students' chronic absenteeism and helped students develop positive learning habits and attitudes.…

  8. The Dielectric Wall Accelerator

    SciTech Connect

    Caporaso, George J.; Chen, Yu-Jiuan; Sampayan, Stephen E.

    2009-01-01

    The Dielectric Wall Accelerator (DWA), a class of induction accelerators, employs a novel insulating beam tube to impress a longitudinal electric field on a bunch of charged particles. The surface flashover characteristics of this tube may permit the attainment of accelerating gradients on the order of 100 MV/m for accelerating pulses on the order of a nanosecond in duration. A virtual traveling wave of excitation along the tube is produced at any desired speed by controlling the timing of pulse generating modules that supply a tangential electric field to the tube wall. Because of the ability to control the speed of this virtual wave, the accelerator is capable of handling any charge to mass ratio particle; hence it can be used for electrons, protons and any ion. The accelerator architectures, key technologies and development challenges will be described.

  9. Switched matrix accelerator

    SciTech Connect

    Whittum, David H.; Tantawi, Sami G.

    2001-01-01

    We describe a new concept for a microwave circuit functioning as a charged-particle accelerator at mm wavelengths, permitting an accelerating gradient higher than conventional passive circuits can withstand consistent with cyclic fatigue. The device provides acceleration for multiple bunches in parallel channels, and permits a short exposure time for the conducting surface of the accelerating cavities. Our analysis includes scalings based on a smooth transmission line model and a complementary treatment with a coupled-cavity simulation. We also provide an electromagnetic design for the accelerating structure, arriving at rough dimensions for a seven-cell accelerator matched to standard waveguide and suitable for bench tests at low power in air at 91.392 GHz. A critical element in the concept is a fast mm-wave switch suitable for operation at high power, and we present the considerations for implementation in an H-plane tee. We discuss the use of diamond as the photoconductor switch medium.

  10. Switched Matrix Accelerator

    SciTech Connect

    Whittum, David H

    2000-10-04

    We describe a new concept for a microwave circuit functioning as a charged-particle accelerator at mm-wavelengths, permitting an accelerating gradient higher than conventional passive circuits can withstand consistent with cyclic fatigue. The device provides acceleration for multiple bunches in parallel channels, and permits a short exposure time for the conducting surface of the accelerating cavities. Our analysis includes scalings based on a smooth transmission line model and a complementary treatment with a coupled-cavity simulation. We provide also an electromagnetic design for the accelerating structure, arriving at rough dimensions for a seven-cell accelerator matched to standard waveguide and suitable for bench tests at low power in air at 91.392. GHz. A critical element in the concept is a fast mm-wave switch suitable for operation at high-power, and we present the considerations for implementation in an H-plane tee. We discuss the use of diamond as the photoconductor switch medium.

  11. Iowa Acceleration Scale Manual: A Guide for Whole-Grade Acceleration K-8. (3rd Edition, Manual)

    ERIC Educational Resources Information Center

    Assouline, Susan G.; Colangelo, Nicholas; Lupkowski-Shoplik, Ann; Forstadt, Leslie; Lipscomb, Jonathon

    2009-01-01

    Feedback from years of nationwide use has resulted in a 3rd Edition of this unique, systematic, and objective guide to considering and implementing academic acceleration. Developed and tested by the Belin-Blank Center at the University of Iowa, the IAS ensures that acceleration decisions are systematic, thoughtful, well reasoned, and defensible.…

  12. Wake field accelerators

    SciTech Connect

    Wilson, P.B.

    1986-02-01

    In a wake field accelerator a high current driving bunch injected into a structure or plasma produces intense induced fields, which are in turn used to accelerate a trailing charge or bunch. The basic concepts of wake field acceleration are described. Wake potentials for closed cavities and periodic structures are derived, as are wake potentials on a collinear path with a charge distribution. Cylindrically symmetric structures excited by a beam in the form of a ring are considered. (LEW)

  13. ACCELERATION RESPONSIVE SWITCH

    DOEpatents

    Chabrek, A.F.; Maxwell, R.L.

    1963-07-01

    An acceleration-responsive device with dual channel capabilities whereby a first circuit is actuated upon attainment of a predetermined maximum acceleration level and when the acceleration drops to a predetermined minimum acceleriltion level another circuit is actuated is described. A fluid-damped sensing mass slidably mounted in a relatively frictionless manner on a shaft through the intermediation of a ball bushing and biased by an adjustable compression spring provides inertially operated means for actuating the circuits. (AEC)

  14. Optically pulsed electron accelerator

    DOEpatents

    Fraser, John S.; Sheffield, Richard L.

    1987-01-01

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radio frequency powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  15. Optically pulsed electron accelerator

    DOEpatents

    Fraser, J.S.; Sheffield, R.L.

    1985-05-20

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radiofrequency-powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  16. Acceleration of polarized protons in circular accelerators

    SciTech Connect

    Courant, E.D.; Ruth, R.D.

    1980-09-12

    The theory of depolarization in circular accelerators is presented. The spin equation is first expressed in terms of the particle orbit and then converted to the equivalent spinor equation. The spinor equation is then solved for three different situations: (1) a beam on a flat top near a resonance, (2) uniform acceleration through an isolated resonance, and (3) a model of a fast resonance jump. Finally, the depolarization coefficient, epsilon, is calculated in terms of properties of the particle orbit and the results are applied to a calculation of depolarization in the AGS.

  17. Charged particle accelerator grating

    DOEpatents

    Palmer, Robert B.

    1986-01-01

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams into the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  18. Particle acceleration in flares

    NASA Technical Reports Server (NTRS)

    Benz, Arnold O.; Kosugi, Takeo; Aschwanden, Markus J.; Benka, Steve G.; Chupp, Edward L.; Enome, Shinzo; Garcia, Howard; Holman, Gordon D.; Kurt, Victoria G.; Sakao, Taro

    1994-01-01

    Particle acceleration is intrinsic to the primary energy release in the impulsive phase of solar flares, and we cannot understand flares without understanding acceleration. New observations in soft and hard X-rays, gamma-rays and coherent radio emissions are presented, suggesting flare fragmentation in time and space. X-ray and radio measurements exhibit at least five different time scales in flares. In addition, some new observations of delayed acceleration signatures are also presented. The theory of acceleration by parallel electric fields is used to model the spectral shape and evolution of hard X-rays. The possibility of the appearance of double layers is further investigated.

  19. Accelerator-based BNCT.

    PubMed

    Kreiner, A J; Baldo, M; Bergueiro, J R; Cartelli, D; Castell, W; Thatar Vento, V; Gomez Asoia, J; Mercuri, D; Padulo, J; Suarez Sandin, J C; Erhardt, J; Kesque, J M; Valda, A A; Debray, M E; Somacal, H R; Igarzabal, M; Minsky, D M; Herrera, M S; Capoulat, M E; Gonzalez, S J; del Grosso, M F; Gagetti, L; Suarez Anzorena, M; Gun, M; Carranza, O

    2014-06-01

    The activity in accelerator development for accelerator-based BNCT (AB-BNCT) both worldwide and in Argentina is described. Projects in Russia, UK, Italy, Japan, Israel, and Argentina to develop AB-BNCT around different types of accelerators are briefly presented. In particular, the present status and recent progress of the Argentine project will be reviewed. The topics will cover: intense ion sources, accelerator tubes, transport of intense beams, beam diagnostics, the (9)Be(d,n) reaction as a possible neutron source, Beam Shaping Assemblies (BSA), a treatment room, and treatment planning in realistic cases.

  20. Accelerator-based BNCT.

    PubMed

    Kreiner, A J; Baldo, M; Bergueiro, J R; Cartelli, D; Castell, W; Thatar Vento, V; Gomez Asoia, J; Mercuri, D; Padulo, J; Suarez Sandin, J C; Erhardt, J; Kesque, J M; Valda, A A; Debray, M E; Somacal, H R; Igarzabal, M; Minsky, D M; Herrera, M S; Capoulat, M E; Gonzalez, S J; del Grosso, M F; Gagetti, L; Suarez Anzorena, M; Gun, M; Carranza, O

    2014-06-01

    The activity in accelerator development for accelerator-based BNCT (AB-BNCT) both worldwide and in Argentina is described. Projects in Russia, UK, Italy, Japan, Israel, and Argentina to develop AB-BNCT around different types of accelerators are briefly presented. In particular, the present status and recent progress of the Argentine project will be reviewed. The topics will cover: intense ion sources, accelerator tubes, transport of intense beams, beam diagnostics, the (9)Be(d,n) reaction as a possible neutron source, Beam Shaping Assemblies (BSA), a treatment room, and treatment planning in realistic cases. PMID:24365468