1,399 research outputs found
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 agentâs decision-making process. This paper takes one âemotionâ, 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 ârationalised actionâ, 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 âcrime is normalâ 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
Viscosity in the escape-rate formalism
We apply the escape-rate formalism to compute the shear viscosity in terms of
the chaotic properties of the underlying microscopic dynamics. A first passage
problem is set up for the escape of the Helfand moment associated with
viscosity out of an interval delimited by absorbing boundaries. At the
microscopic level of description, the absorbing boundaries generate a fractal
repeller. The fractal dimensions of this repeller are directly related to the
shear viscosity and the Lyapunov exponent, which allows us to compute its
values. We apply this method to the Bunimovich-Spohn minimal model of viscosity
which is composed of two hard disks in elastic collision on a torus. These
values are in excellent agreement with the values obtained by other methods
such as the Green-Kubo and Einstein-Helfand formulas.Comment: 16 pages, 16 figures (accepted in Phys. Rev. E; October 2003
Influence of large local and non-local bispectra on primordial black hole abundance
Primordial black holes represent a unique probe to constrain the early
universe on small scales - providing the only constraints on the primordial
power spectrum on the majority of scales. However, these constraints are
strongly dependent on even small amounts of non-Gaussianity, which is
unconstrained on scales significantly smaller than those visible in the CMB.
This paper goes beyond previous considerations to consider the effects of a
bispectrum of the equilateral, orthogonal and local shapes with arbitrary
magnitude upon the abundance of primordial black holes. Non-Gaussian density
maps of the early universe are generated from a given bispectrum and used to
place constraints on the small scale power spectrum. When small, we show that
the skewness provides an accurate estimate for how the constraint depends on
non-Gaussianity, independently of the shape of the bispectrum. We show that the
orthogonal template of non-Gaussianity has an order of magnitude weaker effect
on the constraints than the local and equilateral templates.Comment: 11 pages, 4 figures, updated to match published version in
JCAP02(2016)029, Journal of Cosmology and Astroparticle Physics, Volume 2016,
February 201
Liquid antiferromagnets in two dimensions
It is shown that, for proper symmetry of the parent lattice,
antiferromagnetic order can survive in two-dimensional liquid crystals and even
isotropic liquids of point-like particles, in contradiction to what common
sense might suggest. We discuss the requirements for antiferromagnetic order in
the absence of translational and/or orientational lattice order. One example is
the honeycomb lattice, which upon melting can form a liquid crystal with
quasi-long-range orientational and antiferromagnetic order but short-range
translational order. The critical properties of such systems are discussed.
Finally, we draw conjectures for the three-dimensional case.Comment: 4 pages RevTeX, 4 figures include
Evaluation of Irradiated Mandibles Using Emission Tomography, Bone Scans, and Radiography
This study compared radiographs, bone scans, and computed emission tomograms with histologic findings in irradiated mandibles of adult Rhesus monkeys. Although osteocytes were lost in the path of the beam, many vessels were partially or totally occluded, the periosteum degenerated, the marrow became fibrotic, and cancellous bone proliferated abundantly, no changes were noted with radiography, conventional bone scanning, or computed emission tomograms. These clinical methods of examination may misrepresent the true condition of irradiated bone because of inadequate sensitivity or balance among factors that control radioactive tracer uptake in bone.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68112/2/10.1177_00220345800590120201.pd
Nature of Sonoluminescence: Noble Gas Radiation Excited by Hot Electrons in "Cold" Water
We show that strong electric fields occurring in water near the surface of
collapsing gas bubbles because of the flexoelectric effect can provoke dynamic
electric breakdown in a micron-size region near the bubble and consider the
scenario of the SBSL. The scenario is: (i) at the last stage of incomplete
collapse of the bubble the gradient of pressure in water near the bubble
surface has such a value and sign that the electric field arising from the
flexoelectric effect exceeds the threshold field of the dynamic electrical
breakdown of water and is directed to the bubble center; (ii) mobile electrons
are generated because of thermal ionization of water molecules near the bubble
surface; (iii) these electrons are accelerated in ''cold'' water by the strong
electric fields; (iv) these hot electrons transfer noble gas atoms dissolved in
water to high-energy excited states and optical transitions between these
states produce SBSL UV flashes in the trasparency window of water; (v) the
breakdown can be repeated several times and the power and duration of the UV
flash are determined by the multiplicity of the breakdowns. The SBSL spectrum
is found to resemble a black-body spectrum where temperature is given by the
effective temperature of the hot electrons. The pulse energy and some other
characteristics of the SBSL are found to be in agreement with the experimental
data when realistic estimations are made.Comment: 11 pages (RevTex), 1 figure (.ps
Recommended from our members
An ultrafast x-ray detector system at an elliptically polarizingundulator beamline
An ultrafast x-ray detector system is under development atLawrence Berkeley National Laboratory (LBNL) for application primarily tostudyies of ultrafast magnetization dynamics. The system consists of a fslaser, an x-ray streak camera and an ellipitically polarization undulator(EPU) beamline. Polarized x-rays from an EPU can be used to measure x-raymagnetic circular dichroism (XMCD) of a sample. XMCD has the uniqueability to independently measure orbit and spin magnetization withsub-monolayer sensitivity and element specificity. The streak camera hassimultaneously a sub-picosecond temporal resolution and a high spatialresolution. The combination of the streak camera and EPU allows us tostudy the transfer of angular momentum from spin to orbit to the latticein the sample on an ultrafast time scale. We describe here theperformance of the ultrafast detector, the laser and the x-raysynchronization system. The observation of the demagnetization process ofdifferent samples demonstrates the ability of the apparatus
The National Dutch Breast Implant Registry: user-reported experiences and importance
Background: Robust (inter-)national breast implant registries are important. For some, registries are an administrative burden, for others they represent a solution for the discussions involving breast implants. The DBIR is one of the first national, opt-out, clinical registries of breast implants, providing information for clinical auditing and product recall. Four years after its introduction, it is time to address usersâ comments in order to keep improving quality of registration, and patient safety. This study assesses usersâ feedback focusing on importance of registration, logistics and user experience, and areas of improvement. Methods: In May 2018, a standardized online studyâspecific questionnaire was sent out to all members of the Netherlands Society of Plastic Surgery. Descriptive statistics were reported in absolute frequencies and/or percentages. Results: A total of 102 members responded to the questionnaire (response rate, 24.2%). Of all respondents, 97.1% were actively registering in DBIR. Respondents rated the importance of registration in DBIR as 8.1 out of 10 points. Ninety-one respondents suggested improvements for the DBIR. All comments were related to registration convenience and provision of automatically generated data. Conclusions: Respondents believe that registration is highly important and worth the administrative burden. However, we should collectively keep improving accuracy, usability and sustainability of breast
Inflationary Perturbations: the Cosmological Schwinger Effect
This pedagogical review aims at presenting the fundamental aspects of the
theory of inflationary cosmological perturbations of quantum-mechanical origin.
The analogy with the well-known Schwinger effect is discussed in detail and a
systematic comparison of the two physical phenomena is carried out. In
particular, it is demonstrated that the two underlying formalisms differ only
up to an irrelevant canonical transformation. Hence, the basic physical
mechanisms at play are similar in both cases and can be reduced to the
quantization of a parametric oscillator leading to particle creation due to the
interaction with a classical source: pair production in vacuum is therefore
equivalent to the appearance of a growing mode for the cosmological
fluctuations. The only difference lies in the nature of the source: an electric
field in the case of the Schwinger effect and the gravitational field in the
case of inflationary perturbations. Although, in the laboratory, it is
notoriously difficult to produce an electric field such that pairs extracted
from the vacuum can be detected, the gravitational field in the early universe
can be strong enough to lead to observable effects that ultimately reveal
themselves as temperature fluctuations in the Cosmic Microwave Background.
Finally, the question of how quantum cosmological perturbations can be
considered as classical is discussed at the end of the article.Comment: 49 pages, 6 figures, to appear in a LNP volume "Inflationary
Cosmology
WKB approximation for inflationary cosmological perturbations
A new method for predicting inflationary cosmological perturbations, based on
the Wentzel-Kramers-Brillouin (WKB) approximation, is presented. A general
expression for the WKB scalar and tensor power spectra is derived. The main
advantage of the new scheme of approximation is that it is valid even if the
slow-roll conditions are violated. The method is applied to power-law
inflation, which allows a comparison with an exact result. It is demonstrated
that the WKB approximation predicts the spectral indices exactly and the
amplitude with an error lower than 10%, even in regimes far from
scale-invariance. The new method of approximation is also applied to a
situation where the slow-roll conditions hold. It is shown that the result
obtained bears close resemblance with the standard slow-roll calculation.
Finally, some possible improvements are briefly mentioned.Comment: 11 pages, 1 figure, RevTeX; minor changes, reference added (v2);
typos corrected (v3
- âŠ