23,933 research outputs found
Strangeness enhancement at LHC
We study production of strangeness in the hot QGP fireball in conditions
achieved at LHC, and use these results to obtain soft (strange) hadron
multiplicities. We compare the chemical equilibrium and non-equilibrium
conditions and identify characteristic experimental observables.Comment: Presented at SQM07, to appear in JPG special issue. One table with
prediction
Patients' and relatives' assessment of clozapine treatment
Published version: http://journals.cambridge.org/action/displayJournal?jid=PS
``Plug and play'' systems for quantum cryptography
We present a time-multiplexed interferometer based on Faraday mirrors, and
apply it to quantum key distribution. The interfering pulses follow exactly the
same spatial path, ensuring very high stability and self balancing. Use of
Faraday mirrors compensates automatically any birefringence effects and
polarization dependent losses in the transmitting fiber. First experimental
results show a fringe visibility of 0.9984 for a 23km-long interferometer,
based on installed telecom fibers.Comment: LaTex, 6 pages, with 2 Postscript figures, Submitted to Applied
Physics Letter
Phase conversion in a weakly first-order quark-hadron transition
We investigate the process of phase conversion in a thermally-driven {\it
weakly} first-order quark-hadron transition. This scenario is physically
appealing even if the nature of this transition in equilibrium proves to be a
smooth crossover for vanishing baryonic chemical potential. We construct an
effective potential by combining the equation of state obtained within Lattice
QCD for the partonic sector with that of a gas of resonances in the hadronic
phase, and present numerical results on bubble profiles, nucleation rates and
time evolution, including the effects from reheating on the dynamics for
different expansion scenarios. Our findings confirm the standard picture of a
cosmological first-order transition, in which the process of phase conversion
is entirely dominated by nucleation, also in the case of a weakly first-order
transition. On the other hand, we show that, even for expansion rates much
lower than those expected in high-energy heavy ion collisions, nucleation is
very unlikely, indicating that the main mechanism of phase conversion is
spinodal decomposition. Our results are compared to those obtained for a
strongly first-order transition, as the one provided by the MIT bag model.Comment: 12 pages, 10 figures; v2: 1 reference added, minor modifications,
matches published versio
High Ratio of 44Ti/56Ni in Cas A and Axisymmetric Collapse-Driven Supernova Explosion
The large abundance ratio of in Cas A is puzzling. In fact,
the ratio seems to be larger than the theoretical constraint derived by Woosley
& Hoffman (1991). However, this constraint is obtained on the assumption that
the explosion is spherically symmetric, whereas Cas A is famous for the
asymmetric form of the remnant. Recently, Nagataki et al. (1997) calculated the
explosive nucleosynthesis of axisymmetrically deformed collapse-driven
supernova. They reported that the ratio of was enhanced by
the stronger alpha-rich freezeout in the polar region. In this paper, we apply
these results to Cas A and examine whether this effect can explain the large
amount of and the large ratio of . We demonstrate
that the conventional spherically symmetric explosion model can not explain the
Ti mass produced in Cas A if its lifetime is shorter than 80
years and the intervening space is transparent to the gamma-ray line from the
decay of Ti. On the other hand, we show the axisymmetric explosion
models can solve the problem. We expect the same effect from a three
dimensionally asymmetric explosion, since the stronger alpha-rich freezeout
will also occur in that case in the region where the larger energy is
deposited.Comment: 10 pages, LaTeX text and 3 postscript figure
Larval development of the carrion-breeding flesh fly, Sarcophaga (Liosarcophaga) tibialis Macquart (Diptera: Sarcophagidae), at constant temperatures
Larvae of Sarcophaga (Liosarcophaga) tibialis Macquart were raised on chicken liver under six different constant temperatures. Maximum survival indicated an optimal developmental temperature of near 20°C, while trends in mortality, larval length and larval mass implied that the thermal window for successful development lay between 15°C and 30°C. Using a recently described method to estimate a simple thermal summation model, it was found that the timing of the end of the feeding phase could be estimated by a developmental zero (D0) of 5.2°C (S.E. = 1.21) and a thermal summation constant (K) of 106.4 d°C (S.E. = 8.31) and of the end of the wandering phase by D0 = 4.1°C (S.E. = 0.39) and K = 126.7 d°C (S.E. = 3.28). Published development times at constant temperatures were compiled for 19 other species of flesh flies, and the developmental constants were calculated for six species for which sufficient data were accumulated
Levels of genetic polymorphism: marker loci versus quantitative traits
Species are the units used to measure ecological diversity and alleles are the units of genetic diversity. Genetic variation within and among species has been documented most extensively using allozyme electrophoresis. This reveals wide differences in genetic variability within, and genetic distances among, species, demonstrating that species are not equivalent units of diversity. The extent to which the pattern observed for allozymes can be used to infer patterns of genetic variation in quantitative traits depends on the forces generating and maintaining variability. Allozyme variation is probably not strictly neutral but, nevertheless, heterozygosity is expected to be influenced by population size and genetic distance will be affected by time since divergence. The same is true for quantitative traits influenced by many genes and under weak stabilizing selection. However, the limited data available suggest that allozyme variability is a poor predictor of genetic variation in quantitative traits within populations. It is a better predictor of general phenotypic divergence and of postzygotic isolation between populations or species, but is only weakly correlated with prezygotic isolation. Studies of grasshopper and planthopper mating signal variation and assortative mating illustrate how these characters evolve independently of general genetic and morphological variation. The role of such traits in prezygotic isolation, and hence speciation, means that they will contribute significantly to the diversity of levels of genetic variation within and among species
Comparison of data on Mutation Frequencies of Mice Caused by Radiation - Low Dose Model -
We propose LD(Low Dose) model, the extension of LDM model which was proposed
in the previous paper [Y. Manabe et al.: J. Phys. Soc. Jpn. 81 (2012) 104004]
to estimate biological damage caused by irradiation. LD model takes account of
all the considerable effects including cell death effect as well as
proliferation, apoptosis, repair. As a typical example of estimation, we apply
LD model to the experiment of mutation frequency on the responses induced by
the exposure to low levels of ionizing radiation. The most famous and extensive
experiments are those summarized by Russell and Kelly [Russell, W. L. & Kelly,
E. M: Proc. Natl Acad. Sci. USA 79 (1982) 539-541], which are known as
'Mega-mouse project'. This provides us with important information of the
frequencies of transmitted specific-locus mutations induced in mouse
spermatogonia stem-cells. It is found that the numerical results of the
mutation frequency of mice are in reasonable agreement with the experimental
data: the LD model reproduces the total dose and dose rate dependence of data
reasonably. In order to see such dose-rate dependence more explicitly, we
introduce the dose-rate effectiveness factor (DREF). This represents a sort of
preventable effects such as repair, apoptosis and death of broken cells, which
are to be competitive with proliferation effect of broken cells induced by
irradiation.Comment: subimitting to J. Phys. Soc. Jpn, 32 pages, 8 figure
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