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Thermalization and the chromo-Weibel instability
Despite the apparent success of ideal hydrodynamics in describing the
elliptic flow data which have been produced at Brookhaven National Lab's
Relativistic Heavy Ion Collider, one lingering question remains: is the use of
ideal hydrodynamics at times t < 1 fm/c justified? In order to justify its use
a method for rapidly producing isotropic thermal matter at RHIC energies is
required. One of the chief obstacles to early isotropization/thermalization is
the rapid longitudinal expansion of the matter during the earliest times after
the initial nuclear impact. As a result of this expansion the parton
distribution functions become locally anisotropic in momentum space. In
contrast to locally isotropic plasmas anisotropic plasmas have a spectrum of
soft unstable modes which are characterized by exponential growth of transverse
chromo-magnetic/-electric fields at short times. This instability is the QCD
analogue of the Weibel instability of QED. Parametrically the chromo-Weibel
instability provides the fastest method for generation of soft background
fields and dominates the short-time dynamics of the system.Comment: 8 pages, 4 figures, Invited plenary talk given at the 19th
International Conference on Ultrarelativistic Nucleus-Nucleus Collisions:
Quark Matter 2006 (QM 2006), Shanghai, China, 14-20 Nov 200
Branching ratio change in K- absorption at rest and the nature of the Lambda(1405)
We investigate in-medium corrections to the branching ratio in K- absorption
at rest and their effect on the (positively and negatively) charged pion
spectrum. The in-medium corrections are due to Pauli blocking, which arises if
the Lambda(1405) is assumed to be a -nucleon bound state and leads to
a density and momentum dependent mass shift of the Lambda(1405). Requiring that
the optical potential as well as the branching ratio are derived from the same
elementary T-matrix, we find that the in-medium corrected, density dependent
T-matrix gives a better description of the K- absorption reaction than the
free, density-independent one. This result suggests that the dominant component
of the Lambda(1405) wave function is the bound state.Comment: 8 Pages, Revtex with epsf, and embedded 8 ps figure
Electron transport in Coulomb- and tunnel-coupled one-dimensional systems
We develop a linear theory of electron transport for a system of two
identical quantum wires in a wide range of the wire length L, unifying both the
ballistic and diffusive transport regimes. The microscopic model, involving the
interaction of electrons with each other and with bulk acoustical phonons
allows a reduction of the quantum kinetic equation to a set of coupled
equations for the local chemical potentials for forward- and backward-moving
electrons in the wires. As an application of the general solution of these
equations, we consider different kinds of electrical contacts to the
double-wire system and calculate the direct resistance, the transresistance, in
the presence of tunneling and Coulomb drag, and the tunneling resistance. If L
is smaller than the backscattering length l_P, both the tunneling and the drag
lead to a negative transresistance, while in the diffusive regime (L >>l_P) the
tunneling opposes the drag and leads to a positive transresistance. If L is
smaller than the phase-breaking length, the tunneling leads to interference
oscillations of the resistances that are damped exponentially with L.Comment: Text 14 pages in Latex/Revtex format, 4 Postscript figure
"Hiato"/ "Gap"
“Hiato” foi o conto representado por mim e pela artista Sansorai Oliveira, e nossa proposta de intervenção artística consistiu em proporcionar ao público uma experiência de convívio, leitura, sensibilização, reconhecimento do universo do conto “Hiato” e exploração do espaço da Biblioteca Mario de Andrade , através do convite a realizarmos juntos uma travessia imaginária pelo sertão, tal qual os dois vaqueiros personagens do conto
PENGARUH KONFLIK ANTAR INDIVIDU DAN KONFLIK ANTAR DEPARTEMEN TERHADAP KINERJA KARYAWAN PT. OSSI WOODLAND PRIMA DI GRESIK
Proses pencapruan tujuan organisasi sangat mungkin terjadi ketidakperpaduan atau tarik menarik kepentingan, sehingga timbul perselisihan atau konflik (Widagdo dan Yulianto, 1992:95). Konflik yang muncul dalam perusahaan dapat berpengaruh terhadap gairah kerja karyawan baik itu secara negatif maupun positif Berpengaruh negatif bila konflik menjadi indikator menurunnya gairah kerja yang berakibat terganggunya kegiatan perusahaan sehingga tujuan perusahaan tidak tercapai secara optimal. Sedangkan berpengaruh positif apabila konflik pada tingkat tertentu yang sesuai dengan kondisi perusahaan dapat lebih memacu gairah karyawan dimana pada diri karyawan tersebut akan timbul keinginan yang kuat untuk melakukan sesuatu sehingga tercipta kinerja yang memuaskan. Ini merupakan salah satu modal untuk kelangsungan atau kontinuitas perusahaan. Penelitian ini diharapkan dapat memberi gambaran tentang sejauh mana pengaruh konflik antar karyawan terhadap kinerja karyawan pada PT. Ossi Woodland Prima di Gresik
Oxygen Tension Modulates Neurite Outgrowth in PC12 Cells Through A Mechanism Involving HIF and VEGF
Cell-based approaches are a promising therapeutic strategy for treating injuries to the nervous system, but the optimal means to promote neurite extension and direct cellular behavior are unclear. Previous studies have examined the behavior of neural-like cells in ambient air (21% oxygen tension), yet these conditions are not representative of the physiological oxygen microenvironment of neural tissues. We hypothesized that neuronal differentiation of a model neural cell line (PC12) could be controlled by modulating local oxygen tension. Compared to ambient conditions, PC12 cells cultured in reduced oxygen exhibited significant increases in neurite extension and total neurite length, with 4% oxygen yielding the highest levels of both indicators. We confirmed neurite extension was mediated through oxygen-responsive mechanisms using small molecules that promote or inhibit HIF-1α stabilization. The hypoxic target gene Vegf was implicated as a neurotrophic factor, as neurite formation at 21% oxygen was mimicked with exogenous VEGF, and a VEGF-neutralizing antibody attenuated neurite formation under reduced oxygen conditions. These findings demonstrate that behavior of neural-like cells is driven by the oxygen microenvironment via VEGF function, and suggest promising approaches for future applications in neural repair
Absorption of phi mesons in near-threshold proton-nucleus reactions
In the framework of the nuclear spectral function approach for incoherent
primary proton--nucleon and secondary pion--nucleon production processes we
study the inclusive meson production in the interaction of 2.83 GeV
protons with nuclei. In particular, the A-dependences of the absolute and
relative meson yields are investigated within the different scenarios
for its in-medium width as well as for the cross section ratio . Our model calculations take into account
the acceptance window of the ANKE facility used in a recent experiment
performed at COSY. They show that the pion--nucleon production channel
contributes distinctly to the creation in heavy nuclei in the chosen
kinematics and, hence, has to be taken into consideration on close examination
of the dependences of the phi meson yields on the target mass number with the
aim to get information on its width in the medium. They also demonstrate that
the experimentally unknown ratio has a weak effect on the A-dependence of the relative meson
production cross section at incident energy of present interest, whereas it is
found to be appreciably sensitive to the phi in-medium width, which means that
this relative observable can indeed be useful to help determine the above width
from the direct comparison the results of our calculations with the future data
from the respective ANKE-at-COSY experiment.Comment: 16 pages, 9 figure
Climate Change Affects Reproductive Phenology in Lianas of Australia’s Wet Tropics
Lianas are increasing in abundance in many tropical forests. This increase can alter forest structure and decrease both carbon storage and tree diversity via antagonistic relationships between lianas and their host trees. Climate change is postulated as an underlying driver of increasing liana abundances, via increases in dry-season length, forest-disturbance events, and atmospheric CO2 concentrations; all factors thought to favour lianas. However, the impact of climate change on liana reproductive phenology, an underlying determinant of liana abundance, has been little studied, particularly outside of Neotropical forests. Over a 15-year period (2000–2014), we examined the phenological patterns of a liana community in intact rainforests of the Wet Tropics bioregion of Australia; a World Heritage Area and hotspot of floral diversity. Specifically, we assessed (1) flowering and fruiting patterns of liana species; (2) potential climate drivers of flowering and fruiting activity; and (3) the influence of El Niño-related climatic disturbances on liana phenology. We found that flowering and fruiting of the studied liana species increased over time. Liana reproduction, moreover, rose in apparent response to higher temperatures and reduced rainfall. Finally, we found flowering and fruiting of the liana species increased following El Niño events. These results suggest that liana reproduction and abundance are likely to increase under predicted future climate regimes, with potentially important impacts on the survival, growth, and reproduction of resident trees and thus the overall health of Australian tropical rainforests
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