1,550 research outputs found
Two interacting diffusing particles on low-dimensional discrete structures
In this paper we study the motion of two particles diffusing on
low-dimensional discrete structures in presence of a hard-core repulsive
interaction. We show that the problem can be mapped in two decoupled problems
of single particles diffusing on different graphs by a transformation we call
'diffusion graph transform'. This technique is applied to study two specific
cases: the narrow comb and the ladder lattice. We focus on the determination of
the long time probabilities for the contact between particles and their
reciprocal crossing. We also obtain the mean square dispersion of the particles
in the case of the narrow comb lattice. The case of a sticking potential and of
'vicious' particles are discussed.Comment: 9 pages, 6 postscript figures, to appear in 'Journal of Physics
A',-January 200
Danube loess stratigraphy - Towards a pan-European loess stratigraphic model
The Danube River drainage basin is the second largest river catchment in Europe and contains a significant and extensive region of thick loess deposits that preserve a record of a wide variety of recent and past environments. Indeed, the Danube River and tributaries may themselves be responsible for the transportation of large volumes of silt that ultimately drive loess formation in the middle and lower reaches of this large catchment. However, this vast loess province lacks a unified stratigraphic scheme. European loess research started in the late 17th century in the Danube Basin with the work of Count Luigi Ferdinand Marsigli. Since that time numerous investigations provided the basis for the pioneering stratigraphic framework proposed initially by Kukla (1970, 1977) in his correlations of loess with deep-sea sediments. Loess-palaeosol sequences in the middle and lower reaches of the Danube River basin were a key part of this framework and contain some of the longest and most complete continental climate records in Europe, covering more than the last million years. However, the very size of the Danube loess belt and the large number of countries it covers presents a major limiting factor in developing a unified approach that enables continental scale analysis of the deposits. Local loess-palaeosol stratigraphic schemes have been defined separately in different countries and the difficulties in correlating such schemes, which often change significantly with advances in age-dating, have limited the number of basin-wide studies. A unified basin-wide stratigraphic model would greatly alleviate these difficulties and facilitate research into the wider significance of these loess records. Therefore we review the existing stratigraphic schemes and define a new Danube Basin wide loess stratigraphy based around a synthetic type section of the Mošorin and Stari Slankamen sites in Serbia. We present a detailed comparison with the sedimentological and palaeoclimatic records preserved in sediments of the Chinese Loess Plateau, with the oxygen isotope records from deep-sea sediments, and with classic European Pleistocene stratigraphic subdivisions. The hierarchy of Danubian stratigraphic units is determined by climatically controlled environmental shifts, in a similar way to the Chinese loess stratigraphic scheme. A new unified Danube loess stratigraphic model has a number of advantages, including preventing confusion resulting from the use of multiple national schemes, a more transparent basis, and the potential to set Pleistocene palaeoenvironmental changes recorded in the Danube catchment area into a global context. The use of a very simple labelling system based on the well-established Chinese loess scheme facilitates interpretation of palaeoenvironmental information reported from the Danube Basin loess sites in a wider more accessible context that can be readily correlated world-wide. This stratigraphic approach also provides, for the first time, an appropriate framework for the development of an integrated, pan-European and potentially pan-Eurasian loess stratigraphic scheme. © 2015 Elsevier B.V
Comparing the Costs and Acceptability of Three Fidelity Assessment Methods for Assertive Community Treatment
Successful implementation of evidence-based practices requires valid, yet practical fidelity monitoring. This study compared the costs and acceptability of three fidelity assessment methods: on-site, phone, and expert-scored self-report. Thirty-two randomly selected VA mental health intensive case management teams completed all fidelity assessments using a standardized scale and provided feedback on each. Personnel and travel costs across the three methods were compared for statistical differences. Both phone and expert-scored self-report methods demonstrated significantly lower costs than on-site assessments, even when excluding travel costs. However, participants preferred on-site assessments. Remote fidelity assessments hold promise in monitoring large scale program fidelity with limited resources
The Comparative Effectiveness of a Model of Job Development versus Treatment as Usual
Job development is critical to assisting people with serious disabilities to obtain jobs, but little is known about the actual methods that make job development effective. Using a post-only quasi-experimental design, this study examined the effects of the Conceptual Selling® method on the number of job development contacts and number of job placements. By controlling for employment specialists' characteristics (age, length of time in current position, years of human service experience, and years of business experience), the authors determined that the employment specialists trained in the Conceptual Selling® method had more job development contacts per employer, leading to more effective job placements for employers contacted, than the control group
Catecholaminergic ventricular tachycardia initially diagnosed as right ventricular outflow tract arrhythmia : differential diagnosis of CPVT, LQTS and RVOT arrhythmia.
We described a case of 33 year-old woman with catecholaminergic polymorphic ventricular tachycardia (VT) with first
presentation as syncope in age of 14. In subsequent ECGs premature ventricular contractions (PVC) with morphology of left
bundle branch block-like pattern with positive R wave in leads: II, III and aVF what suggested PVC arising from right ventricular outflow tract were observed. Nonsustained VT was observed. No ventricular arrhythmias were induced during EPS. The
2 unsuccessful sessions of ablation were performed in the right ventricular outflow area. The exercise test provoked bidirectional VT. The adrenaline infusion provoked bidirectional nonsustained VT and the U wave amplitude augmentation. Betablocker was initiated (bisoprolol). The patient is free of symptoms, only single PVC is observed
Group report: What are the observed and anticipated meteorological and climatic responses to aerosol forcing?
Exact time-dependent correlation functions for the symmetric exclusion process with open boundary
As a simple model for single-file diffusion of hard core particles we
investigate the one-dimensional symmetric exclusion process. We consider an
open semi-infinite system where one end is coupled to an external reservoir of
constant density and which initially is in an non-equilibrium state
with bulk density . We calculate the exact time-dependent two-point
density correlation function and the mean and variance of the integrated average net flux
of particles that have entered (or left) the system up to time .
We find that the boundary region of the semi-infinite relaxing system is in a
state similar to the bulk state of a finite stationary system driven by a
boundary gradient. The symmetric exclusion model provides a rare example where
such behavior can be proved rigorously on the level of equal-time two-point
correlation functions. Some implications for the relaxational dynamics of
entangled polymers and for single-file diffusion in colloidal systems are
discussed.Comment: 11 pages, uses REVTEX, 2 figures. Minor typos corrected and reference
17 adde
Illocutionary harm
A number of philosophers have become interested in the ways that individuals are subject to harm as the performers of illocutionary acts. This paper offers an account of the underlying structure of such harms: I argue that speakers are the subjects of illocutionary harm when there is interference in the entitlement structure of their linguistic activities. This interference comes in two forms: denial and incapacitation. In cases of denial, a speaker is prevented from achieving the outcomes to which they are entitled by their speech. In cases of incapacitation, a speaker’s standing to expect certain outcomes is itself undermined. I also discuss how individual speakers are subject to interference along two dimensions: as exercisers of certain non-linguistic capacities, and as producers of meaningful speech
The influence of riparian invasion by the terrestrial shrub Lonicera maackii on aquatic macroinvertebrates in temperate forest headwater streams
The ecology of headwater streams is tightly linked to the riparian zone through organic matter subsidies which are highly susceptible to alteration due to biological invasion. Lonicera maackii is a non-native shrub that is a highly successful invader of headwater stream riparian zones in the American Midwest. We assessed effects on benthic macroinvertebrates across a gradient of invasion intensity from references sites with minimal invasion to a site that had a very heavy invasion. Benthic macroinvertebrates were sampled throughout the year and compositional differences were assessed using Non-metric Multidimensional Scaling ordination, and by comparing the prevalence of sensitive (Ephemeroptera, Plectoptera, and Trichoptera: EPT) and tolerant (Chironomidae) macroinvertebrate taxa. We found strong evidence of variation among macroinvertebrate communities across the invasion gradient (ANOSIM R = 0.215, P = 0.004) and particularly strong separation between one of our reference sites with minimal invasion and the site with the heaviest invasion. Analysis of EPT taxa indicated a significant overall effect and pairwise comparisons indicated that the site with the heaviest invasion had the lowest percentage of sensitive taxa (P \u3c 0.05). Our analysis of chironomids did not yield a statistically discernable effect, although the pattern of the data suggest higher dominance in the site with the heaviest invasion. These stream-scale results bolster prior laboratory and field experiments and provide evidence that terrestrial invasion of L. maackiiimpacts the benthic community present in headwater streams. These results provide impetus to re-focus stream management recommendations to include practices that control invasive plants in riparian forests
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