52,717 research outputs found
Mate Preferences in the US and Singapore: A Cross-cultural Test of the Mate Preference Priority Model
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A Multilayer Monte Carlo Model for the Investigation of Optical Path and Penetration Depth at Different Perfusion States of the Colon
There is a great interest in monitoring the oxygen supply delivered to the colon. Insufficient oxygen delivery may lead to hypoxia, sepsis, multiorgan dysfunction and death. For assessing colonic perfusion, more information and understanding is required relating to the light-interaction within the colonic tissue. A multilayer Monte Carlo model of a healthy human colon has been developed to investigate the light-tissue behavior during different perfusion states within the mucosal layer of the colon. Results from a static multilayer model of optical path and reflectance at two wavelengths, 660 nm and 880 nm, through colon tissue, containing different volume fractions of blood with a fixed oxygen saturation are presented. The effect on the optical path and penetration depth with varying blood volumes within the mucosa for each wavelength has been demonstrated. The simulation indicated both wavelengths of photons penetrated similar depths, entering the muscularis layer
Magnetotransport in a model of a disordered strange metal
Despite much theoretical effort, there is no complete theory of the 'strange'
metal state of the high temperature superconductors, and its
linear-in-temperature, , resistivity. Recent experiments showing an
unexpected linear-in-field, , magnetoresistivity have deepened the puzzle.
We propose a simple model of itinerant electrons, interacting via random
couplings with electrons localized on a lattice of quantum 'dots' or 'islands'.
This model is solvable in a large- limit, and can reproduce observed
behavior. The key feature of our model is that the electrons in each quantum
dot are described by a Sachdev-Ye-Kitaev model describing electrons without
quasiparticle excitations. For a particular choice of the interaction between
the itinerant and localized electrons, this model realizes a controlled
description of a diffusive marginal-Fermi liquid (MFL) without momentum
conservation, which has a linear-in- resistivity and a specific
heat as . By tuning the strength of this interaction relative
to the bandwidth of the itinerant electrons, we can additionally obtain a
finite- crossover to a fully incoherent regime that also has a linear-in-
resistivity. We show that the MFL regime has conductivities which scale as a
function of ; however, its magnetoresistance saturates at large . We
then consider a macroscopically disordered sample with domains of MFLs with
varying densities of electrons. Using an effective-medium approximation, we
obtain a macroscopic electrical resistance that scales linearly in the magnetic
field applied perpendicular to the plane of the sample, at large . The
resistance also scales linearly in at small , and as at
intermediate . We consider implications for recent experiments reporting
linear transverse magnetoresistance in the strange metal phases of the
pnictides and cuprates.Comment: 21 pages + Appendices + References, 4 figure
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The circulatory impact of dust from dust profile assimilation
We present results from a reanalysis of temperatures, dust columns and dust vertical profiles focussing on the assimilation, distribution and transport of dust in the martian atmosphere. The assimilation of dust vertical information in particular is a valuable technique which has been shown to be of vital importance to a successful assimilation of the martian atmosphere, with the vertical representation of the dust distribution having a critical effect on assimilation results generally.
Atmospheric dust is a key driver of the martian circulation. Dust-induced heating and cooling is a potential feedback mechanism for dust lifting, for example, and can modify the circulation to either enhance or suppress dust storm activity. Accurately representing its complex spatial and temporal distribution is therefore crucial for understanding Mars’ atmospheric dynamics and transport
Flux Tube Model Signals for Baryon Correlations in Heavy Ion Collisions
The flux tube model offers a pictorial description of what happens during the
deconfinement phase transition in QCD. The 3-point vertices of a flux tube
network lead to formation of baryons upon hadronisation. Therefore,
correlations in the baryon number distribution at the last scattering surface
are related to the preceding pattern of the flux tube vertices, and provide a
signature of the nearby deconfinement phase transition. I discuss the nature of
the expected signal, which should be observable in heavy ion collisions at RHIC
and LHC.Comment: LaTeX, 9 pages, 5 figures, (v2) Several arguments expanded for
clarity, (v3) Minor typesetting changes, published versio
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