5,232 research outputs found
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Identification of suitable biomarkers for stress and emotion detection for future personal affective wearable sensors
Skin conductivity (i.e., sweat) forms the basis of many physiology-based emotion and stress detection systems. However, such systems typically do not detect the biomarkers present in sweat, and thus do not take advantage of the biological information in the sweat. Likewise, such systems do not detect the volatile organic components (VOC’s) created under stressful conditions. This work presents a review into the current status of human emotional stress biomarkers and proposes the major potential biomarkers for future wearable sensors in affective systems. Emotional stress has been classified as a major contributor in several social problems, related to crime, health, the economy, and indeed quality of life. While blood cortisol tests, electroencephalography and physiological parameter methods are the gold standards for measuring stress; however, they are typically invasive or inconvenient and not suitable for wearable real-time stress monitoring. Alternatively, cortisol in biofluids and VOCs emitted from the skin appear to be practical and useful markers for sensors to detect emotional stress events. This work has identified antistress hormones and cortisol metabolites as the primary stress biomarkers that can be used in future sensors for wearable affective systems
Climatic and eustatic controls on the development of a Late Triassic source rock in the Jameson Land Basin, East Greenland
This work was undertaken as part of the continuing work of CASP in East Greenland. The sponsoring companies are thanked for their continued support of this work. Help in the field by T. Kinnaird and useful discussions with A. Whitham are gratefully acknowledged. The reviews of L. Clemmensen and an anonymous reviewer, and the input from S. Jones led to improvements to the original paper.Peer reviewedPostprin
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Staphylococcus aureus FadB is a dehydrogenase that mediates cholate resistance and survival under human colonic conditions
Staphylococcus aureus is a common colonizer of the human gut and in doing so it must be able to resist the actions of the host’s innate defences. Bile salts are a class of molecules that possess potent antibacterial activity that control growth. Bacteria that colonize and survive in that niche must be able to resist the action of bile salts, but the mechanisms by which S. aureus does so are poorly understood. Here we show that FadB is a bile-induced oxidoreductase which mediates bile salt resistance and when heterologously expressed in Escherichia coli renders them resistant. Deletion of fadB attenuated survival of S. aureus in a model of the human distal colon
Asymptotic iteration method for eigenvalue problems
An asymptotic interation method for solving second-order homogeneous linear
differential equations of the form y'' = lambda(x) y' + s(x) y is introduced,
where lambda(x) \neq 0 and s(x) are C-infinity functions. Applications to
Schroedinger type problems, including some with highly singular potentials, are
presented.Comment: 14 page
A Spatially Resolved Inner Hole in the Disk around GM Aurigae
We present 0.3 arcsec resolution observations of the disk around GM Aurigae
with the Submillimeter Array (SMA) at a wavelength of 860 um and with the
Plateau de Bure Interferometer at a wavelength of 1.3 mm. These observations
probe the distribution of disk material on spatial scales commensurate with the
size of the inner hole predicted by models of the spectral energy distribution.
The data clearly indicate a sharp decrease in millimeter optical depth at the
disk center, consistent with a deficit of material at distances less than ~20
AU from the star. We refine the accretion disk model of Calvet et al. (2005)
based on the unresolved spectral energy distribution (SED) and demonstrate that
it reproduces well the spatially resolved millimeter continuum data at both
available wavelengths. We also present complementary SMA observations of CO
J=3-2 and J=2-1 emission from the disk at 2" resolution. The observed CO
morphology is consistent with the continuum model prediction, with two
significant deviations: (1) the emission displays a larger CO J=3-2/J=2-1 line
ratio than predicted, which may indicate additional heating of gas in the upper
disk layers; and (2) the position angle of the kinematic rotation pattern
differs by 11 +/- 2 degrees from that measured at smaller scales from the dust
continuum, which may indicate the presence of a warp. We note that
photoevaporation, grain growth, and binarity are unlikely mechanisms for
inducing the observed sharp decrease in opacity or surface density at the disk
center. The inner hole plausibly results from the dynamical influence of a
planet on the disk material. Warping induced by a planet could also potentially
explain the difference in position angle between the continuum and CO data
sets.Comment: 12 pages, 6 figures, accepted for publication in Ap
Dust Properties of Protoplanetary Disks in the Taurus-Auriga Star Forming Region from Millimeter Wavelengths
We present the most sensitive 3 mm-survey to date of protoplanetary disks
carried in the Taurus-Auriga star forming region (average rms of about 0.3
mJy), using the IRAM PdBI. With our high detection rate of 17/19, we provide
the first detections at wavelengths longer than about 1 mm for 12 sources. This
enables us to study statistically the mm SED slopes and dust properties of
faint disks and compare them to brighter disks using a uniform analysis method.
With these new data and literature measurements at sub-millimeter and
millimeter wavelengths, we analyze the dust properties of a sample of 21
isolated disks around T Tauri stars in the Taurus-Auriga star forming region.
Together with the information about the disks spatial extension from sub/mm-mm
interferometric studies, we derive from the observed sub-mm/mm spectral energy
distribution constraints on the dust opacity law at these wavelengths, using
two-layer flared disk models and a self-consistent dust model that takes
properly into account the variation of the dust opacity with grain growth. We
find evidence for the presence in the disk midplane of dust particles that have
grown to sizes as large as at least 1 millimeter in all the disks of our
sample, confirming what was previously observed on smaller brighter objects.
This indicates that the dust coagulation from ISM dust to mm-sized grains is a
very fast process in protoplanetary disks, that appears to occur before a young
stellar object enters the Class II evolutionary stage. Also, the amount of
these large grains in the disk outer regions is stationary throughout all the
Class II evolutionary stage, indicating that mechanisms slowing down the dust
inward migration are playing an important role in the Taurus-Auriga
protoplanetary disks.Comment: 17 pages, 10 figures, accepted for publication in A&
Photoevaporation of protoplanetary discs I: hydrodynamic models
In this paper we consider the effect of the direct ionizing stellar radiation
field on the evolution of protoplanetary discs subject to photoevaporative
winds. We suggest that models which combine viscous evolution with
photoevaporation of the disc (e.g. Clarke, Gendrin & Sotomayor 2001)
incorrectly neglect the direct field after the inner disc has drained, at late
times in the evolution. We construct models of the photoevaporative wind
produced by the direct field, first using simple analytic arguments and later
using detailed numerical hydrodynamics. We find that the wind produced by the
direct field at late times is much larger than has previously been assumed, and
we show that the mass-loss rate scales as (where is the
radius of the instantaneous inner disc edge). We suggest that this result has
important consequences for theories of disc evolution, and go on to consider
the effects of this result on disc evolution in detail in a companion paper
(Alexander, Clarke & Pringle 2006b).Comment: 13 pages, 9 figures. Accepted for publication in MNRA
Multi-Particle Pseudopotentials for Multi-Component Quantum Hall Systems
The Haldane pseudopotential construction has been an extremely powerful
concept in quantum Hall physics --- it not only gives a minimal description of
the space of Hamiltonians but also suggests special model Hamiltonians (those
where certain pseudopotential are set to zero) that may have exactly solvable
ground states with interesting properties. The purpose of this paper is to
generalize the pseudopotential construction to situations where interactions
are N-body and where the particles may have internal degrees of freedom such as
spin or valley index. Assuming a rotationally invariant Hamiltonian, the
essence of the problem is to obtain a full basis of wavefunctions for N
particles with fixed relative angular momentum L. This basis decomposes into
representations of SU(n) with n the number of internal degrees of freedom. We
give special attention to the case where the internal degree of freedom has n=2
states, which encompasses the important cases of spin-1/2 particles and quantum
Hall bilayers. We also discuss in some detail the cases of spin-1 particles
(n=3) and graphene (n=4, including two spin and two valley degrees of freedom).Comment: 46 pages ; 9 tables ; no figures. (The revision fixes a number of
typos and updates the formatting
Situationally edited empathy: an effect of socio-economic structure on individual choice
Criminological theory still operates with deficient models of the offender as agent, and of social influences on the agent’s decision-making process. This paper takes one ‘emotion’, empathy, which is theoretically of considerable importance in influencing the choices made by agents; particularly those involving criminal or otherwise harmful action. Using a framework not of rational action, but of ‘rationalised action’, the paper considers some of the effects on individual psychology of social, economic, political and cultural structure. It is suggested that the climate-setting effects of these structures promote normative definitions of social situations which allow unempathic, harmful action to be rationalised through the situational editing of empathy. The ‘crime is normal’ argument can therefore be extended to include the recognition that the uncompassionate state of mind of the criminal actor is a reflection of the self-interested values which govern non-criminal action in wider society
Ruling Out Multi-Order Interference in Quantum Mechanics
Quantum mechanics and gravitation are two pillars of modern physics. Despite
their success in describing the physical world around us, they seem to be
incompatible theories. There are suggestions that one of these theories must be
generalized to achieve unification. For example, Born's rule, one of the axioms
of quantum mechanics could be violated. Born's rule predicts that quantum
interference, as shown by a double slit diffraction experiment, occurs from
pairs of paths. A generalized version of quantum mechanics might allow
multi-path, i.e. higher order interferences thus leading to a deviation from
the theory. We performed a three slit experiment with photons and bounded the
magnitude of three path interference to less than 10-2 of the expected two-path
interference, thus ruling out third and higher order interference and providing
a bound on the accuracy of Born's rule. Our experiment is consistent with the
postulate both in semi-classical and quantum regimes
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