2,381 research outputs found
Thermodynamic processes generated by a class of completely positive quantum operations
An attempt toward the operational formulation of quantum thermodynamics is
made by employing the recently proposed operations forming positive
operator-valued measures for generating thermodynamic processes. The quantity
of heat as well as the von Neumann entropy monotonically increases under the
operations. The fixed point analysis shows that repeated applications of these
operations to a given system transform from its pure ground state at zero
temperature to the completely random state in the high temperature limit with
intermediate states being generically out of equilibrium. It is shown that the
Clausius inequality can be violated along the processes, in general. A
bipartite spin-1/2 system is analyzed as an explicit example.Comment: 22 pages and 1 figure. Modern Physics Letters B, in pres
Topological defect formation in quenched ferromagnetic Bose-Einstein condensates
We study the dynamics of the quantum phase transition of a ferromagnetic
spin-1 Bose-Einstein condensate from the polar phase to the broken-axisymmetry
phase by changing magnetic field, and find the spontaneous formation of spinor
domain walls followed by the creation of polar-core spin vortices. We also find
that the spin textures depend very sensitively on the initial noise
distribution, and that an anisotropic and colored initial noise is needed to
reproduce the Berkeley experiment [Sadler et al., Nature 443, 312 (2006)]. The
dynamics of vortex nucleation and the number of created vortices depend also on
the manner in which the magnetic field is changed. We point out an analogy
between the formation of spin vortices from domain walls in a spinor BEC and
that of vortex-antivortex pairs from dark solitons in a scalar BEC.Comment: 10 pages, 11 figure
Saccharomyces arboricola and Its Hybrids’ Propensity for Sake Production: Interspecific Hybrids Reveal Increased Fermentation Abilities and a Mosaic Metabolic Profile
The use of interspecific hybrids during the industrial fermentation process has been well established, positioning the frontier of advancement in brewing to capitalize on the potential of Saccharomyces hybridization. Interspecific yeast hybrids used in modern monoculture inoculations benefit from a wide range of volatile metabolites that broaden the organoleptic complexity. This is the first report of sake brewing by Saccharomyces arboricola and its hybrids. S. arboricola x S. cerevisiae direct-mating generated cryotolerant interspecific hybrids which increased yields of ethanol and ethyl hexanoate compared to parental strains, important flavor attributes of fine Japanese ginjo sake rice wine. Hierarchical clustering heatmapping with principal component analysis for metabolic profiling was used in finding low levels of endogenous amino/organic acids clustered S. arboricola apart from the S. cerevisiae industrial strains. In sake fermentations, hybrid strains showed a mosaic profile of parental strains, while metabolic analysis suggested S. arboricola had a lower amino acid net uptake than S. cerevisiae. Additionally, this research found an increase in ethanolic fermentation from pyruvate and increased sulfur metabolism. Together, these results suggest S. arboricola is poised for in-depth metabolomic exploration in sake fermentation
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Mechanisms of hepatic triglyceride accumulation in non-alcoholic fatty liver disease
Non-alcoholic fatty liver disease (NAFLD) is characterized by hepatic lipid accumulation in the absence of excess alcohol intake. NAFLD is the most common chronic liver disease, and ongoing research efforts are focused on understanding the underlying pathobiology of hepatic steatosis with the anticipation that these efforts will identify novel therapeutic targets. Under physiological conditions, the low steady-state triglyceride concentrations in the liver are attributable to a precise balance between acquisition by uptake of non-esterified fatty acids from the plasma and by de novo lipogenesis, versus triglyceride disposal by fatty acid oxidation and by the secretion of triglyceride-rich lipoproteins. In NAFLD patients, insulin resistance leads to hepatic steatosis by multiple mechanisms. Greater uptake rates of plasma non-esterified fatty acids are attributable to increased release from an expanded mass of adipose tissue as a consequence of diminished insulin responsiveness. Hyperinsulinemia promotes the transcriptional upregulation of genes that promote de novo lipogenesis in the liver. Increased hepatic lipid accumulation is not offset by fatty acid oxidation or by increased secretion rates of triglyceride-rich lipoproteins. This review discusses the molecular mechanisms by which hepatic triglyceride homeostasis is achieved under normal conditions, as well as the metabolic alterations that occur in the setting of insulin resistance and contribute to the pathogenesis of NAFLD
Kaluza-Klein bubble like structure and celestial sphere in inflationary universe
We consider five dimensional deSitter spacetimes with a deficit angle due to
the presence of a closed 2-brane and identify one dimension as an extra
dimension. From the four dimensional viewpoint we can see that the spacetime
has a structure similar to a Kaluza-Klein bubble of nothing, that is, four
dimensional spacetime ends at the 2-brane. Since a spatial section of the full
deSitter spacetime has the topology of a sphere, the boundary surface surrounds
the remaining four dimensional spacetime, and can be considered as the
celestial sphere. After the spacetime is created from nothing via an instanton
which we describe, some four dimensional observers in it see the celestial
sphere falling down, and will be in contact with a 2-brane attached on it.Comment: 5pages, 4figures, to be published in GR
Knots in a Spinor Bose-Einstein Condensate
We show that knots of spin textures can be created in the polar phase of a
spin-1 Bose-Einstein condensate, and discuss experimental schemes for their
generation and probe, together with their lifetime.Comment: 4 pages, 3 figure
Topological classification of vortex-core structures of spin-1 Bose-Einstein condensates
We classify vortex-core structures according to the topology of the order
parameter space. By developing a method to characterize how the order parameter
changes inside the vortex core. We apply this method to the spin-1
Bose-Einstein condensates and show that the vortex-core structures are
classified by winding numbers that are locally defined in the core region. We
also show that a vortex-core structure with a nontrivial winding number can be
stabilized under a negative quadratic Zeeman effect.Comment: 16 pages, 6 figure
A superfluid 4He interferometer operating near 2 K
Matter-wave interferometers reveal some of the most fascinating phenomena of
the quantum world. Phase shifts due to rotation (the Sagnac effect) for
neutrons, free atoms and superfluid 3He reveal the connection of matter waves
to a non-rotating inertial frame. In addition, phase shifts in electron waves
due to magnetic vector potentials (the Aharonov-Bohm effect) show that physical
states can be modified in the absence of classical forces. We report here the
observation of interference induced by the Earth's rotation in superfluid 4He
at 2 K, a temperature 2000 times higher than previously achieved with 3He. This
interferometer, an analog of a dc-SQUID, employs a recently reported phenomenon
wherein superfluid 4He exhibits quantum oscillations in an array of sub-micron
apertures. We find that the interference pattern persists not only when the
aperture array current-phase relation is a sinusoidal function characteristic
of the Josephson effect, but also at lower temperatures where it is linear and
oscillations occur by phase slips. The modest requirements for the
interferometer (2 K cryogenics and fabrication of apertures at the level of
100nm) and its potential resolution suggest that, when engineering challenges
such as vibration isolation are met, superfluid 4He interferometers could
become important scientific probes.Comment: 8 pages, 2 figure
Positions of Point-Nodes in Borocarbide Superconductor YNi2B2C
To determine the superconducting gap function of YNi2B2C, we calculate the
local density of states (LDOS) around a single vortex core with the use of
Eilenberger theory and the band structure calculated by local density
approximation assuming various gap structures with point-nodes at different
positions. We also calculate the angular-dependent heat capacity in the vortex
state on the basis of the Doppler-Shift method. Comparing our results with the
STM/STS experiment, the angular-dependent heat capacity and thermal
conductivity, we propose the gap-structure of YNi2B2C, which has the
point-nodes and gap minima along . Our gap-structure is consistent with
all results of angular-resolved experiments.Comment: 7 pages, 5 figure
Hubungan Kondisi Sanitasi Dasar dengan Keluhan Kesehatan Diare Serta Kualitas Air pada Pengguna Air Sungai Deli di Kelurahan Sukaraja Kecamatan Medan Maimun Tahun 2012
Correlation between basic sanitary condition and Diarrhea with the water quality in Sukaraja Subdistrict Medan Maimun District 2012. Diarrhea on Deli river users was fairly high. The cause was suspected by unhealthy basic sanitation and people\u27s habits in using river water as water source. The study aimed to analyze the correlation between condition of basic sanitation and diarrheaon Deli river users and to know Deli water riverquality. The study was conducted by descriptive method with cross sectional study design. This research conducted along the riverside area of Deli on Sukaraja village Medan Maimun Sub District with 59 housewives sample.The result showed there was correlation between sanitation of water resources (p=0,024), family latrines (p=0,016), garbage disposal (p=0,045) and diarrhea, and there was no correlation between sanitation of waste water treatment (p=0,050) and diarrhea. From the results oflaboratory tests,river water quality in upstream area did not exceed the the specified threshold value, such as temperature, nitrate, selenium, and E. coli. According to PP no. 82 tahun 2001, while in middle and downstream area number of E. Coli was foundhad exceeded the specified threshold value. Based on the result of study, Deli river in middle and downstream area had contaminated by feces and there was a significant correlation betweenbasic sanitation and diarrhea. Suggested forLocal Government Medan District to be more intensive on water supply and environmental health program and people to care about their basic sanitation
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