4,714 research outputs found
Generalized Pauli principle for particles with distinguishable traits
The s=3/2 Ising spin chain with uniform nearest-neighbor coupling, quadratic
single-site potential, and magnetic field is shown to be equivalent to a system
of 17 species of particles with internal structure. The same set of particles
(with different energies) is shown to generate the spectrum of the s=1/2 Ising
chain with dimerized nearest-neighbor coupling. The particles are free of
interaction energies even at high densities. The mutual exclusion statistics of
particles from all species is determined by their internal structure and
encoded in a generalized Pauli principle. The exact statistical mechanical
analysis can be performed for thermodynamically open or closed systems and with
arbitrary energies assigned to all particle species. Special circumstances make
it possible to merge two or more species into a single species. All traits that
distinguish the original species become ignorable. The particles from the
merged species are effectively indistinguishable and obey modified exclusion
statistics. Different mergers may yield the same endproduct, implying that the
inverse process (splitting any species into subspecies) is not unique. In a
macroscopic system of two merged species at thermal equilibrium, the
concentrations of the original species satisfy a functional relation governed
by their mutual statistical interaction. That relation is derivable from an
extremum principle. In the Ising context the system is open and the particle
energies depend on the Hamiltonian parameters. Simple models of polymerization
and solitonic paramagnetism each represent a closed system of two species that
can transform into each other. Here they represent distinguishable traits with
different energies of the same physical particle.Comment: 12 pages, 7 figures, 6 table
Text mining meets community curation: a newly designed curation platform to improve author experience and participation at WormBase
Biological knowledgebases rely on expert biocuration of the research literature to maintain up-to-date collections of data organized in machine-readable form. To enter information into knowledgebases, curators need to follow three steps: (i) identify papers containing relevant data, a process called triaging; (ii) recognize named entities; and (iii) extract and curate data in accordance with the underlying data models. WormBase (WB), the authoritative repository for research data on Caenorhabditis elegans and other nematodes, uses text mining (TM) to semi-automate its curation pipeline. In addition, WB engages its community, via an Author First Pass (AFP) system, to help recognize entities and classify data types in their recently published papers. In this paper, we present a new WB AFP system that combines TM and AFP into a single application to enhance community curation. The system employs string-searching algorithms and statistical methods (e.g. support vector machines (SVMs)) to extract biological entities and classify data types, and it presents the results to authors in a web form where they validate the extracted information, rather than enter it de novo as the previous form required. With this new system, we lessen the burden for authors, while at the same time receive valuable feedback on the performance of our TM tools. The new user interface also links out to specific structured data submission forms, e.g. for phenotype or expression pattern data, giving the authors the opportunity to contribute a more detailed curation that can be incorporated into WB with minimal curator review. Our approach is generalizable and could be applied to additional knowledgebases that would like to engage their user community in assisting with the curation. In the five months succeeding the launch of the new system, the response rate has been comparable with that of the previous AFP version, but the quality and quantity of the data received has greatly improved
Bipolar spectrum disorders in a clinical sample of patients with Internet addiction: Hidden comorbidity or differential diagnosis?
Background and aims
Behavioral addictions and bipolar disorders have a certain probability of co-occurrence. While the presence of a manic episode has been defined as an exclusion criterion for gambling disorder, no such exclusion has been formulated for Internet addiction.
Methods
A clinical sample of 368 treatment seekers presenting with excessive to addictive Internet use was screened for bipolar spectrum disorders using the Mood Disorder Questionnaire. Psychopathology was assessed by the Symptom Checklist 90R and a clinical interview was administered to screen for comorbid disorders.
Results
Comorbid bipolar disorders were more frequent in patients meeting criteria for Internet addiction (30.9%) than among the excessive users (5.6%). This subgroup showed heightened psychopathological symptoms, including substance use disorders, affective disorders and personality disorders. Further differences were found regarding frequency of Internet use regarding social networking sites and online-pornography.
Discussion
Patients with Internet addiction have a heightened probability for meeting criteria of bipolar disorders. It is not possible to draw conclusions regarding the direction of this association but it is recommended to implement screening for bipolar disorders in patients presenting with Internet addiction.
Conclusion
Similar to gambling disorder, it might prove necessary to subsume bipolar disorders as an exclusion criterion for the future criteria of Internet addiction
Comprehensive systematic review summary: Treatment of tics in people with Tourette syndrome and chronic tic disorders
Objective
To systematically evaluate the efficacy of treatments for tics and the risks associated with their use.
Methods
This project followed the methodologies outlined in the 2011 edition of the American Academy of Neurology\u27s guideline development process manual. We included systematic reviews and randomized controlled trials on the treatment of tics that included at least 20 participants (10 participants if a crossover trial), except for neurostimulation trials, for which no minimum sample size was required. To obtain additional information on drug safety, we included cohort studies or case series that specifically evaluated adverse drug effects in individuals with tics.
Results
There was high confidence that the Comprehensive Behavioral Intervention for Tics was more likely than psychoeducation and supportive therapy to reduce tics. There was moderate confidence that haloperidol, risperidone, aripiprazole, tiapride, clonidine, onabotulinumtoxinA injections, 5-ling granule, Ningdong granule, and deep brain stimulation of the globus pallidus were probably more likely than placebo to reduce tics. There was low confidence that pimozide, ziprasidone, metoclopramide, guanfacine, topiramate, and tetrahydrocannabinol were possibly more likely than placebo to reduce tics. Evidence of harm associated with various treatments was also demonstrated, including weight gain, drug-induced movement disorders, elevated prolactin levels, sedation, and effects on heart rate, blood pressure, and ECGs.
Conclusions
There is evidence to support the efficacy of various medical, behavioral, and neurostimulation interventions for the treatment of tics. Both the efficacy and harms associated with interventions must be considered in making treatment recommendations
Conical defects in growing sheets
A growing or shrinking disc will adopt a conical shape, its intrinsic
geometry characterized by a surplus angle at the apex. If growth is slow,
the cone will find its equilibrium. Whereas this is trivial if , the
disc can fold into one of a discrete infinite number of states if is
positive. We construct these states in the regime where bending dominates,
determine their energies and how stress is distributed in them. For each state
a critical value of is identified beyond which the cone touches itself.
Before this occurs, all states are stable; the ground state has two-fold
symmetry.Comment: 4 pages, 4 figures, LaTeX, RevTeX style. New version corresponds to
the one published in PR
Особенности формирования структуры зоны термического влияния в малоуглеродистой конструкционной стали при многопроходной вневакуумной электронно-лучевой наплавке
В работе представлены результаты исследования влияния многопроходной вневакуумной электронно-лучевой наплавки порошком стали 10Р6М5+30%WC на структуру и свойства зоны термического влияния стали 20. In work results of studies of the effect multipass non-vakuum electron beam of surfacing steel powder 10Р6М5+30%WC on a structure and properties of heat affected zone steel 20
Interface-mediated interactions: Entropic forces of curved membranes
Particles embedded in a fluctuating interface experience forces and torques
mediated by the deformations and by the thermal fluctuations of the medium.
Considering a system of two cylinders bound to a fluid membrane we show that
the entropic contribution enhances the curvature-mediated repulsion between the
two cylinders. This is contrary to the usual attractive Casimir force in the
absence of curvature-mediated interactions. For a large distance between the
cylinders, we retrieve the renormalization of the surface tension of a flat
membrane due to thermal fluctuations.Comment: 11 pages, 5 figures; final version, as appeared in Phys. Rev.
Stability of chemical reaction fronts in solids:Analytical and numerical approaches
Localized chemical reactions in deformable solids are considered. A chemical transformation is accompanied by the transformation strain and emerging mechanical stresses, which affect the kinetics of the chemical reaction front to the reaction arrest. A chemo-mechanical coupling via the chemical affinity tensor is used, in which the stresses affect the reaction rate. The emphasis is made on the stability of the propagating reaction front in the vicinity of the blocked state. There are two major novel contributions. First, it is shown that for a planar reaction front, the diffusion of the gaseous-type reactant does not influence the stability of the reaction front – the stability is governed only by the mechanical properties of solid reactants and stresses induced by the transformation strain and the external loading, which corresponds to the mathematically analogous phase transition problem. Second, the comparison of two computational approaches to model the reaction front propagation is performed – the standard finite-element method with a remeshing technique to resolve the moving interface is compared to the cut-finite-element-based approach, which allows the interface to cut through the elements and to move independently of the finite-element mesh. For stability problems considered in the present paper, the previously-developed implementation of the cut-element approach has been extended with the additional post-processing procedure that obtains more accurate stresses and strains, relying on the fact that the structured grid is used in the implementation. The approaches are compared using a range of chemo-mechanical problems with stable and unstable reaction fronts.</p
Interaction and thermodynamics of spinons in the XX chain
The mapping between the fermion and spinon compositions of eigenstates in the
one-dimensional spin-1/2 XX model on a lattice with N sites is used to describe
the spinon interaction from two different perspectives: (i) For finite N the
energy of all eigenstates is expressed as a function of spinon momenta and
spinon spins, which, in turn, are solutions of a set of Bethe ansatz equations.
The latter are the basis of an exact thermodynamic analysis in the spinon
representation of the XX model. (ii) For N -> infinity the energy per site of
spinon configurations involving any number of spinon orbitals is expressed as a
function of reduced variables representing momentum, filling, and magnetization
of each orbital. The spins of spinons in a single orbital are found to be
coupled in a manner well described by an Ising-like equivalent-neighbor
interaction, switching from ferromagnetic to antiferromagnetic as the filling
exceeds a critical level. Comparisons are made with results for the
Haldane-Shastry model.Comment: 16 pages, 3 figure
Contact lines for fluid surface adhesion
When a fluid surface adheres to a substrate, the location of the contact line
adjusts in order to minimize the overall energy. This adhesion balance implies
boundary conditions which depend on the characteristic surface deformation
energies. We develop a general geometrical framework within which these
conditions can be systematically derived. We treat both adhesion to a rigid
substrate as well as adhesion between two fluid surfaces, and illustrate our
general results for several important Hamiltonians involving both curvature and
curvature gradients. Some of these have previously been studied using very
different techniques, others are to our knowledge new. What becomes clear in
our approach is that, except for capillary phenomena, these boundary conditions
are not the manifestation of a local force balance, even if the concept of
surface stress is properly generalized. Hamiltonians containing higher order
surface derivatives are not just sensitive to boundary translations but also
notice changes in slope or even curvature. Both the necessity and the
functional form of the corresponding additional contributions follow readily
from our treatment.Comment: 8 pages, 2 figures, LaTeX, RevTeX styl
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