116,377 research outputs found
Spin facilitated Ising model with long range interaction
We study the dynamics of a spin facilitated Ising model with long range
kinetic constraints. To formulate those restrictions within an analytical
approach we introduce the size of a kinetic active environment of a given spin.
Based on a Master equation in second quantized form, the spin-autocorrelation
function is calculated. It exhibits a pronounced slow dynamics, manifested by a
logarithmic decay law of the spin-autocorrelation function. In case of an
infinite kinetic interaction the mean field solution yields an asymptotic exact
expression for the autocorrelation function which is in excellent agreement
with Monte Carlo Simulations for finite interaction lengths. With increasing
size of the active zone the cooperative processes, characterizing the
facilitated model with short range kinetic interaction, become irrelevant. We
demonstrate that the long range kinetic interaction dominates the actual spin
configurations of the whole system and the mean field solution is the exact
one.Comment: 18 pages, 5 figure
Collective Diffusion and a Random Energy Landscape
Starting from a master equation in a quantum Hamiltonian form and a coupling
to a heat bath we derive an evolution equation for a collective hopping process
under the influence of a stochastic energy landscape. There results different
equations in case of an arbitrary occupation number per lattice site or in a
system under exclusion. Based on scaling arguments it will be demonstrated that
both systems belong below the critical dimension to the same universality
class leading to anomalous diffusion in the long time limit. The dynamical
exponent can be calculated by an expansion. Above the
critical dimension we discuss the differences in the diffusion constant for
sufficient high temperatures. For a random potential we find a higher mobility
for systems with exclusion.Comment: 15 pages, no figure
Ants and Fairies: The Debate with Darwinism in A. S. Byatt’s Morpho Eugenia
Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 dofinansowane zostało ze środków MNiSW w ramach działalności upowszechniającej nauk
Review of Nelson's analysis of Bell's theorem
This article contains a review of Nelson's analysis of Bell's theorem. It
shows that Bell's inequalities can be violated with a theory of local random
variables if one accepts that the outcomes of these variables are not
predetermined prior to measurement. The article describes the relation between
Bell's theorem and the Strong Free Will theorem of Conway and Kochen. Then, the
original articles of Bell are analyzed in detail. Following an article of
Faris, it is explained that Bell's work on the hidden variable question in fact
describes two separate theorems. Bell's first theorem says that there can be no
model for the singlet state where an outcome does not depend locally on the
settings of the detector where the outcome was measured. Bell's second theorem
shows that Bell's inequalities can be violated by a theory that is either not
deterministic, or violates causality in the sense of relativity or the free
will assumption of the experimenters. It is shown in detail where Bell
implicitly makes the various locality assumptions that Nelson has shown to be
necessary for deriving Bell's inequality. The article closes by relating the
various assumptions needed to derive Bell's theorem with the reality criterion
of EPRComment: 19 pages, section added where Bell's original articles are analyzed
and compared in detail with Nelson's wor
The SPIRE Photometer Interactive Analysis Package SPIA
The Herschel Common Science System (HCSS) (Ott et al. 2006) (Ott & Science
Ground Segment Consortium 2010) is a substantial Java software package,
accompanying the development of the Herschel Mission (Pilbratt et al. 2010),
supporting all of its phases. In particular the reduction of data from the
scientific instruments for instrument checkout, calibration, and astronomical
analysis is one of its major applications. The data reduction software is split
up in modules, called "tasks". Agreed-upon sequences of tasks form pipelines
that deliver well defined standard products for storage in a web-accessible
Herschel Science Archive (HSA) (Leon et al. 2009). However, as astronomers and
instrument scientists continue to characterize instrumental effects,
astronomers already need to publish scientific results and may not have the
time to acquire a sufficiently deep understanding of the system to apply
necessary fixes. There is a need for intermediate level analysis tools that
offer more flexibility than rigid pipelines. The task framework within the HCSS
and the highly versatile Herschel Interactive Processing Environment (HIPE),
together with the rich set of libraries provide the necessary tools to develop
GUI-based interactive analysis packages for the Herschel instruments. The SPIRE
Photometer Interactive Analysis (SPIA) package, that was demonstrated in this
session, proves the validity of the concept for the SPIRE instrument (Griffin
et al. 2010), breaking up the pipeline reduction into logical components,
making all relevant processing parameters available in GUIs, and providing a
more controlled and user-friendly access to the complexities of the system.Comment: Proceedings accompanying a focus demo given at the ADASS 2010 in
Bosto
Qualified Promise: DNA Methylation Assays for the Detection and Classification of Human Cancers
The Psychological Impact of Long-Term Solitary Confinement on Inmates in the United States
Psychological distress among inmates is prevalent in correctional facilities throughout the United States. Although, according to Haney (2003), severe isolation of incarcerates has been commonplace in prisons since their inception, the use of secure housing units (SHU) and the development of ‘supermax’ prisons are becoming increasingly utilized within the last several decades. Legislators have expressed the need to increase punitive measures against delinquents in response to the rising prison population (Arrigo and Bullock 2008). Thus harsher crime control policies, such as administrative and disciplinary segregation, have been established in order to limit the personal freedoms of prisoners (Arrigo and Bullock 2008). Within these institutions, inmates are increasingly subjected to solitary confinement, a method of incarceration characterized by “the confinement of a prisoner in isolation with limited chance for social interaction or environmental stimulus” (The Psychology of Cruelty 2015). Theories surrounding the use of solitary confinement emphasize its potential to deter future misconduct among inmates (Morris 2015); however, little attention has been given to the potential psychological effects of long-term segregation. In response, this paper seeks to examine the exacerbating and detrimental psychological effects experienced by inmates subjected to solitary confinement in the United States
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