2,026 research outputs found
A nonlinear mechanism of charge qubit decoherence in a lossy cavity: the quasi normal mode approach
In the viewpoint of quasi normal modes, we describe a novel decoherence
mechanism of charge qubit of Josephson Junctions (JJ) in a lossy micro-cavity,
which can appear in the realistic experiment for quantum computation based on
JJ qubit. We show that the nonlinear coupling of a charge qubit to quantum
cavity field can result in an additional dissipation of resonant mode due to
its effective interaction between those non-resonant modes and a resonant mode,
which is induced by the charge qubit itself. We calculate the characterized
time of the novel decoherence by making use of the system plus bath method.Comment: 6 pages, 2 figur
Understanding light quanta: First quantization of the free electromagnetic field
The quantization of the electromagnetic field in vacuum is presented without
reference to lagrangean quantum field theory. The equal time commutators of the
fields are calculated from basic principles. A physical discussion of the
commutators suggest that the electromagnetic fields are macroscopic emergent
properties of more fundamental physical system: the photons
Utilizing field collected insects for next generation sequencing: effects of sampling, storage and DNA extraction methods
DNA sequencing technologies continue to advance the biological sciences, expanding
opportunities for genomic studies of nonâmodel organisms for basic and applied
questions. Despite these opportunities, many next generation sequencing protocols
have been developed assuming a substantial quantity of high molecular weight DNA
(>100 ng), which can be difficult to obtain for many study systems. In particular, the
ability to sequence fieldâcollected specimens that exhibit varying levels of DNA degradation
remains largely unexplored. In this study we investigate the influence of
five traditional insect capture and curation methods on DoubleâDigest Restriction
Enzyme Associated DNA (ddRAD) sequencing success for three wild bee species.
We sequenced a total of 105 specimens (between 7â13 specimens per species and
treatment). We additionally investigated how different DNA quality metrics (including
preâsequence concentration and contamination) predicted downstream sequencing
success, and also compared two DNA extraction methods. We report successful
library preparation for all specimens, with all treatments and extraction methods producing
enough highly reliable loci for population genetic analyses. Although results
varied between species, we found that specimens collected by net sampling directly
into 100% EtOH, or by passive trapping followed by 100% EtOH storage before pinning
tended to produce higher quality ddRAD assemblies, likely as a result of rapid
specimen desiccation. Surprisingly, we found that specimens preserved in propylene
glycol during field sampling exhibited lowerâquality assemblies. We provide recommendations
for each treatment, extraction method, and DNA quality assessment,
and further encourage researchers to consider utilizing a wider variety of specimens
for genomic analysesinfo:eu-repo/semantics/publishedVersio
A new dynamic module for in-situ nanomechanical testing at high strain rate
In-situ nanomechanical testing is commonly used to probe surface mechanical properties of bulk materials or thin films, like hardness, Youngâs modulus, Yield stressâŠActually most of the instruments can measure these properties only statically, i.e. a low frequency, leading to property measurement only at low strain rate (usually 10-1s-1 by nanoindentation). This is mainly caused by the low resonance frequency of the system, preventing making tests at higher speed. Performing high dynamic measurements could bring new information on materials properties like deformation mechanism at high strain rate, or high dynamic fatigue properties.
A new high dynamic module usable for in-situ mechanical testing has been developed. It is composed of a small piezotube attached directly behind the tip. Because of the small dimensions of the module, his resonance frequency is very high (higher than 50kHz) in comparison to classical nanomechanical testers, permitting to perform and measure precisely the signals at very high frequency. Moreover, it can be used as a sensor and as an actuator, in x, y and z directions which gives to this module a very large range of measurements.
Firstly, the characteristics, the performances and the limits of the new high dynamic module will be presented. Secondly some indentations experiments performed at high strain rate on nanocrystalline nickel with the in-situ nanomechanical tester (Alemnis Gmbh) equipped with the high dynamic will be presented and discussed (Fig. 1). Finally, some micropillar compression at high strain rate on the same material will be described and discussed
Sire Breed Effect on Beef Longissimus Mineral Concentrations and Their Relationships with Carcass and Palatability Traits
The objective of this study was to evaluate sire breed effect on mineral concentration in beef longissimus thoracis (LT) and investigate the correlations between beef mineral concentrations and carcass and palatability traits. Steer progeny (N = 246) from the Germplasm Evaluation projectâCycle VIII were used in this study. In addition to carcass traits, LT was evaluated for mineral concentrations, WarnerâBratzler shear force, and palatability traits. A mixed linear model estimated breed effects on mineral concentrations. No significant sire breed (P â„ 0.43) or dam breed (P â„ 0.20) effects were identified for mineral concentrations. Pearson correlation coefficients were calculated among mineral concentrations, carcass, and sensory traits. Zinc concentration was positively correlated (P †0.05) with total iron (r = 0.14), heme iron (r = 0.13), and magnesium (r = 0.19). Significant (P \u3c 0.05) correlations were identified between non-heme or heme iron and most traits in this study. Magnesium concentration was correlated with all carcass and palatability traits
Astrophysical and Astrobiological Implications of Gamma-Ray Burst Properties
Combining results for the local cosmic rate and mean peak luminosity of GRBs
with the cosmic history of the star formation rate, we provide estimates for
the local GRB rate per unit blue luminosity in galaxies. We find a typical GRB
rate per unit B luminosity of 2.4x10^-17 h_{70}^2/Lsun/yr. The corresponding
mean rate in the Milky Way is 5.5x10^-7 h_{70}^2/yr. We conclude: 1) the ratio
of supernova rate to isotropic equivalent GRB rate is large: more than 6000
SNIbc per GRB or 30,000 SNII per GRB. GRBs could arise in a large fraction of
black hole-forming events only with collimation in the range 0.01 - 0.001 and a
steep enough slope of the IMF; 2) GRBs cannot account for the majority of large
HI holes observed in galaxies; 3) the probability that the solar system was
exposed to a fluence large enough to melt the chondrules during the first 10^7
yr of solar system history is negligibly small; 4) Even for very opaque
atmospheres, a significant fraction of the GRB energy is transmitted as UV
lines due to excitation by secondary electrons. For eukaryotic-like organisms
in thin atmospheres (e.g. contemporary Mars), or for UV line exposure in thick
atmospheres (e.g. Earth), biologically significant events occur at a rate of
about 100--500 /Gyr. The direct contribution of these "jolts" to mutational
evolution may, however, be negligible because of the short duration of the
GRBs. Evolutionary effects due to partial sterilizations and to longer-lived
disruptions of atmospheric chemistry should be more important. (Abridged)Comment: 36 pages, no figures Accepted by Astrophysical Journal Oct. 2001.
First submitted December,1999. Substantially rewritten discussion of burst
source count distributions and of biological implication
A quantum-mechanical Maxwell's demon
A Maxwell's demon is a device that gets information and trades it in for
thermodynamic advantage, in apparent (but not actual) contradiction to the
second law of thermodynamics. Quantum-mechanical versions of Maxwell's demon
exhibit features that classical versions do not: in particular, a device that
gets information about a quantum system disturbs it in the process. In
addition, the information produced by quantum measurement acts as an additional
source of thermodynamic inefficiency. This paper investigates the properties of
quantum-mechanical Maxwell's demons, and proposes experimentally realizable
models of such devices.Comment: 13 pages, Te
Quantum corrections and black hole spectroscopy
In the work \cite{BRM,RBE}, black hole spectroscopy has been successfully
reproduced in the tunneling picture. As a result, the derived entropy spectrum
of black hole in different gravity (including Einstein's gravity,
Einstein-Gauss-Bonnet gravity and Ho\v{r}ava-Lifshitz gravity) are all evenly
spaced, sharing the same forms as , where physical process is only
confined in the semiclassical framework. However, the real physical picture
should go beyond the semiclassical approximation. In this case, the physical
quantities would undergo higher-order quantum corrections, whose effect on
different gravity shares in different forms. Motivated by these facts, in this
paper we aim to observe how quantum corrections affect black hole spectroscopy
in different gravity. The result shows that, in the presence of higher-order
quantum corrections, black hole spectroscopy in different gravity still shares
the same form as , further confirming the entropy quantum is universal
in the sense that it is not only independent of black hole parameters, but also
independent of higher-order quantum corrections. This is a desiring result for
the forthcoming quantum gravity theory.Comment: 14 pages, no figure, use JHEP3.cls. to be published in JHE
Crossover Scaling in Dendritic Evolution at Low Undercooling
We examine scaling in two-dimensional simulations of dendritic growth at low
undercooling, as well as in three-dimensional pivalic acid dendrites grown on
NASA's USMP-4 Isothermal Dendritic Growth Experiment. We report new results on
self-similar evolution in both the experiments and simulations. We find that
the time dependent scaling of our low undercooling simulations displays a
cross-over scaling from a regime different than that characterizing Laplacian
growth to steady-state growth
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