470 research outputs found
Las etapas del amor en el sufismo persa primitivo de RÄbeâ˛a a RuzbahÄn
Abstract not availabl
Euclidean random matrix theory: low-frequency non-analyticities and Rayleigh scattering
By calculating all terms of the high-density expansion of the euclidean
random matrix theory (up to second-order in the inverse density) for the
vibrational spectrum of a topologically disordered system we show that the
low-frequency behavior of the self energy is given by and not , as claimed previously.
This implies the presence of Rayleigh scattering and long-time tails of the
velocity autocorrelation function of the analogous diffusion problem of the
form .Comment: 27 page
Systematic Approach to Using Isentropic Stress Reverberation Techniques in Approximating Equation of State
Isentropic stress reverberations are used to obtain multiple Hugoniot states from a single plate impact experiment using a layered plate geometry, where a low impedance inner layer is embedded within a high impedance bulk structure. The mathematical framework used in this technique uses the classical Rankine-Hugoniot equations in the method of impedance matching, where the bulk material is required to have a known Hugoniot. Factors including the wave velocities in the materials, input pulse duration, inner layer thickness, and diameter of the test samples affect the number of states that can be generated from a single experiment. Experiments using 6061 aluminum and polycarbonate, respectively, as the bulk material and inner layer, accurately generated six Hugoniot states for the polycarbonate. Experiments using A572 grade 50 structural steel as the bulk material accurately generated ten Hugoniot states for the polycarbonate. For each experiment, the method can be used to generate a Hugoniot equation defining the material response of the inner layer within the domain encompassed by the specific test. The method is also confined to the low to moderate stress regions, within which Hugoniot and isentropic representations of the material are almost identical
The pd <--> pi+ t reaction around the Delta resonance
The pd pi+ t process has been calculated in the energy region around the
Delta-resonance with elementary production/absorption mechanisms involving one
and two nucleons. The isobar degrees of freedom have been explicitly included
in the two-nucleon mechanism via pi-- and rho-exchange diagrams. No free
parameters have been employed in the analysis since all the parameters have
been fixed in previous studies on the simpler pp pi+ d process. The
treatment of the few-nucleon dynamics entailed a Faddeev-based calculation of
the reaction, with continuum calculations for the initial p-d state and
accurate solutions of the three-nucleon bound-state equation. The integral
cross-section was found to be quite sensitive to the NN interaction employed
while the angular dependence showed less sensitivity. Approximately a 4% effect
was found for the one-body mechanism, for the three-nucleon dynamics in the p-d
channel, and for the inclusion of a large, possibly converged, number of
three-body partial states, indicating that these different aspects are of
comparable importance in the calculation of the spin-averaged observables.Comment: 40 Pages, RevTex, plus 5 PostScript figure
Landscape science: a Russian geographical tradition
The Russian geographical tradition of landscape science (landshaftovedenie) is analyzed with particular reference to its initiator, Lev Semenovich Berg (1876-1950). The differences between prevailing Russian and Western concepts of landscape in geography are discussed, and their common origins in German geographical thought in the late nineteenth and early twentieth centuries are delineated. It is argued that the principal differences are accounted for by a number of factors, of which Russia's own distinctive tradition in environmental science deriving from the work of V. V. Dokuchaev (1846-1903), the activities of certain key individuals (such as Berg and C. O. Sauer), and the very different social and political circumstances in different parts of the world appear to be the most significant. At the same time it is noted that neither in Russia nor in the West have geographers succeeded in specifying an agreed and unproblematic understanding of landscape, or more broadly in promoting a common geographical conception of human-environment relationships. In light of such uncertainties, the latter part of the article argues for closer international links between the variant landscape traditions in geography as an important contribution to the quest for sustainability
How Preussag became TUI : kissing too many toads can make you a toad
In the period 1997-2004, Preussag, a diversified German conglomerate of old economy businesses, changed itself into TUI, a company focused almost entirely on tourism and logistics. This paper analyzes how this strategy was executed and how it contributed to Preussagâs underperformance of the stock market. We collect 417 announcements of acquisitions, financial disclosures and other news and disentangle the impact of different parts of the companyâs strategy. We find that only the divestitures created value, that the strategy to invest in tourism destroyed value, and that the acquisition premiums Preussag paid were mostly unjustified. Bad luck like the events of September 11, 2001 cannot account for the poor performance of the stock. Poor management resulted from poor governance, combining a state-owned bank as the largest shareholder, board interlocks, and insufficient managerial incentives. The case shows how divestiture programs increase the liquid resources available to management beyond free operating cash flows and casts doubt on the positive governance role of institutional blockholders
The RHIC SPIN Program: Achievements and Future Opportunities
Time and again, spin has been a key element in the exploration of fundamental
physics. Spin-dependent observables have often revealed deficits in the assumed
theoretical framework and have led to novel developments and concepts. Spin is
exploited in many parity-violating experiments searching for physics beyond the
Standard Model or studying the nature of nucleon-nucleon forces. The RHIC spin
program plays a special role in this grand scheme: it uses spin to study how a
complex many-body system such as the proton arises from the dynamics of QCD.
Many exciting results from RHIC spin have emerged to date, most of them from
RHIC running after the 2007 Long Range Plan. In this document we present
highlights from the RHIC program to date and lay out the roadmap for the
significant advances that are possible with future RHIC running
Fifteen new risk loci for coronary artery disease highlight arterial-wall-specific mechanisms
Coronary artery disease (CAD) is a leading cause of morbidity and mortality worldwide. Although 58 genomic regions have been associated with CAD thus far, most of the heritability is unexplained, indicating that additional susceptibility loci await identification. An efficient discovery strategy may be larger-scale evaluation of promising associations suggested by genome-wide association studies (GWAS). Hence, we genotyped 56,309 participants using a targeted gene array derived from earlier GWAS results and performed meta-analysis of results with 194,427 participants previously genotyped, totaling 88,192 CAD cases and 162,544 controls. We identified 25 new SNP-CAD associations (P < 5 Ă 10(-8), in fixed-effects meta-analysis) from 15 genomic regions, including SNPs in or near genes involved in cellular adhesion, leukocyte migration and atherosclerosis (PECAM1, rs1867624), coagulation and inflammation (PROCR, rs867186 (p.Ser219Gly)) and vascular smooth muscle cell differentiation (LMOD1, rs2820315). Correlation of these regions with cell-type-specific gene expression and plasma protein levels sheds light on potential disease mechanisms
White paper on nuclear astrophysics and low energy nuclear physics Part 1: Nuclear astrophysics
This white paper informs the nuclear astrophysics community and funding agencies about the scientific directions and priorities of the field and provides input from this community for the 2015 Nuclear Science Long Range Plan. It summarizes the outcome of the nuclear astrophysics town meeting that was held on August 21â23, 2014 in College Station at the campus of Texas A&M University in preparation of the NSAC Nuclear Science Long Range Plan. It also reflects the outcome of an earlier town meeting of the nuclear astrophysics community organized by the Joint Institute for Nuclear Astrophysics (JINA) on October 9â10, 2012 Detroit, Michigan, with the purpose of developing a vision for nuclear astrophysics in light of the recent NRC decadal surveys in nuclear physics (NP2010) and astronomy (ASTRO2010). The white paper is furthermore informed by the town meeting of the Association of Research at University Nuclear Accelerators (ARUNA) that took place at the University of Notre Dame on June 12â13, 2014. In summary we find that nuclear astrophysics is a modern and vibrant field addressing fundamental science questions at the intersection of nuclear physics and astrophysics. These questions relate to the origin of the elements, the nuclear engines that drive life and death of stars, and the properties of dense matter. A broad range of nuclear accelerator facilities, astronomical observatories, theory efforts, and computational capabilities are needed. With the developments outlined in this white paper, answers to long standing key questions are well within reach in the coming decade
Catching Element Formation In The Act
Gamma-ray astronomy explores the most energetic photons in nature to address
some of the most pressing puzzles in contemporary astrophysics. It encompasses
a wide range of objects and phenomena: stars, supernovae, novae, neutron stars,
stellar-mass black holes, nucleosynthesis, the interstellar medium, cosmic rays
and relativistic-particle acceleration, and the evolution of galaxies. MeV
gamma-rays provide a unique probe of nuclear processes in astronomy, directly
measuring radioactive decay, nuclear de-excitation, and positron annihilation.
The substantial information carried by gamma-ray photons allows us to see
deeper into these objects, the bulk of the power is often emitted at gamma-ray
energies, and radioactivity provides a natural physical clock that adds unique
information. New science will be driven by time-domain population studies at
gamma-ray energies. This science is enabled by next-generation gamma-ray
instruments with one to two orders of magnitude better sensitivity, larger sky
coverage, and faster cadence than all previous gamma-ray instruments. This
transformative capability permits: (a) the accurate identification of the
gamma-ray emitting objects and correlations with observations taken at other
wavelengths and with other messengers; (b) construction of new gamma-ray maps
of the Milky Way and other nearby galaxies where extended regions are
distinguished from point sources; and (c) considerable serendipitous science of
scarce events -- nearby neutron star mergers, for example. Advances in
technology push the performance of new gamma-ray instruments to address a wide
set of astrophysical questions.Comment: 14 pages including 3 figure
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