3,758 research outputs found

    Broad-tailed force distributions and velocity ordering in a heterogeneous membrane model for collective cell migration

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    Correlated velocity patterns and associated large length-scale transmission of traction forces have been observed in collective live cell migration as a response to a "wound". We argue that a simple physical model of a force-driven heterogeneous elastic membrane sliding over a viscous substrate can qualitatively explain a few experimentally observed facts: (i) the growth of velocity ordering which spreads from the wound boundary to the interior, (ii) the exponential tails of the traction force distributions, and (iii) the swirling pattern of velocities in the interior of the tissue.Comment: 7 pages and 5 figure

    Finding Computer Science Syllabi on the World Wide Web

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    Syllabi contain information useful to students, faculty, and many other people, and given the ubiquity of the WWW many schools are now putting their syllabi online for these people and the general public to access. Even though these syllabi may be available, they might be hard to find. This means that faculty, students, and anyone else who might have an interest in viewing those syllabi might find it useful to be able to browse a collection of reliable syllabi. To build a collection of reliable syllabi it is necessary to find those syllabi on the WWW but this is made easy with a tool like the Google Web API. Once the syllabi are found on the Web it is necessary to examine those syllabi and look for desired characteristics to be sure they are desired syllabi. The syllabi that contain the desired characteristics are kept and the rest are discarded. This elimination process can be accomplished using a tool like a classification tree, more specifically, tools like the Orange Data Mining Library and C4.5. This paper describes the process of finding syllabi on the WWW using the Google Web API, retrieving those syllabi using Python, and filtering them using the Orange Data Mining Library and C4.5 so that a reliable set of syllabi can be constructed

    Cryptosporidium rubeyi n. sp. (Apicomplexa: Cryptosporidiidae) in multiple Spermophilus ground squirrel species.

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    Previously we reported the unique Cryptosporidium sp. "c" genotype (e.g., Sbey03c, Sbey05c, Sbld05c, Sltl05c) from three species of Spermophilus ground squirrel (Spermophilus beecheyi, Spermophilus beldingi, Spermophilus lateralis) located throughout California, USA. This follow-up work characterizes the morphology and animal infectivity of this novel genotype as the final step in proposing it as a new species of Cryptosporidium. Analysis of sequences of 18S rRNA, actin, and HSP70 genes of additional Cryptosporidium isolates from recently sampled California ground squirrels (S. beecheyi) confirms the presence of the unique Sbey-c genotype in S. beecheyi. Phylogenetic and BLAST analysis indicates that the c-genotype in Spermophilus ground squirrels is distinct from Cryptosporidium species/genotypes from other host species currently available in GenBank. We propose to name this c-genotype found in Spermophilus ground squirrels as Cryptosporidium rubeyi n. sp. The mean size of C. rubeyi n. sp. oocysts is 4.67 (4.4-5.0) μm × 4.34 (4.0-5.0) μm, with a length/width index of 1.08 (n = 220). Oocysts of C. rubeyi n. sp. are not infectious to neonatal BALB/c mice and Holstein calves. GenBank accession numbers for C. rubeyi n. sp. are DQ295012, AY462233, and KM010224 for the 18S rRNA gene, KM010227 for the actin gene, and KM010229 for the HSP70 gene

    Interface charged impurity scattering in semiconductor MOSFETs and MODFETs: temperature dependent resistivity and 2D "metallic" behavior

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    We present the results on the anomalous 2D transport behavior by employing Drude-Boltzmann transport theory and taking into account the realistic charge impurity scattering effects. Our results show quantitative agreement with the existing experimental data in several different systems and address the origin of the strong and non-monotonic temperature dependent resistivity.Comment: Presented at SIMD, Dec. 1999 in Hawaii. To be published in Superlattices and Microstructures, May 2000 issu

    Extended electronic states in disordered 1-d lattices: an example

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    We discuss a very simple model of a 1-d disordered lattice, in which {\em all} the electronic eigenstates are extended. The nature of these states is examined from several viewpoints, and it is found that the eigenfunctions are not Bloch functions although they extend throughout the chain. Some typical wavefunctions are plotted. This problem originated in our earlier study of extended states in the quasiperiodic copper-mean lattice [ Sil, Karmakar, Moitra and Chakrabarti, Phys. Rev. B (1993) ]. In the present investigation extended states are found to arise from a different kind of correlation than that of the well-known dimer-type.Comment: 9 pages, 1 figure available on request, LaTex version 2.09, SINP-SSMP93-0

    Exploring the Association between Individual-Level Attributes and Fidelity to a Vocational Rehabilitation Intervention within a Randomised Controlled Trial

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    Understanding what attributes or characteristics of those delivering interventions affect intervention fidelity and patient outcomes is important for contextualising intervention effectiveness. It may also inform implementation of interventions in future research and clinical practice. This study aimed to explore the relationships between attributes of Occupational Therapists (OTs), their faithful delivery of an early stroke specialist vocational rehabilitation intervention (ESSVR), and stroke survivor return-to-work (RTW) outcomes. Thirty-nine OTs were surveyed about their experience and knowledge of stroke and vocational rehabilitation and were trained to deliver ESSVR. ESSVR was delivered across 16 sites in England and Wales between February 2018 and November 2021. OTs received monthly mentoring to support ESSVR delivery. The amount of mentoring each OT received was recorded in OT mentoring records. Fidelity was assessed using an intervention component checklist completed using retrospective case review of one randomly selected participant per OT. Linear and logistic regression analyses explored relationships between OT attributes, fidelity, and stroke survivor RTW outcome. Fidelity scores ranged from 30.8 to 100% (Mean: 78.8%, SD: 19.2%). Only OT engagement in mentoring was significantly associated with fidelity (b = 0.29, 95% CI = 0.05–0.53, p < 0.05). Increased fidelity (OR = 1.06, 95% CI = 1.01–1.1, p = 0.01) and increasing years of stroke rehabilitation experience (OR = 1.17, 95% CI = 1.02–1.35) was significantly associated with positive stroke survivor RTW outcomes. Findings of this study suggest that mentoring OTs may increase fidelity of delivery of ESSVR, which may also be associated with positive stroke survivor return-to-work outcomes. The results also suggest that OTs with more experience of stroke rehabilitation may be able to support stroke survivors to RTW more effectively. Upskilling OTs to deliver complex interventions, such as ESSVR, in clinical trials may require mentoring support in addition to training to ensure fidelity.publishedVersio

    Viral Load Monitoring of Antiretroviral Therapy, cohort viral load and HIV transmission in Southern Africa: A Mathematical Modelling Analysis

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    In low-income settings, treatment failure is often identified using CD4 cell count monitoring. Consequently, patients remain on a failing regimen, resulting in a higher risk of transmission. We investigated the benefit of routine viral load monitoring for reducing HIV transmission

    A few electrons per ion scenario for the B=0 metal-insulator transition in two dimensions

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    We argue on the basis of experimental numbers that the B=0 metal-insulator transition in two dimensions, observed in Si-MOSFETs and in other two-dimensional systems, is likely to be due to a few strongly interacting electrons, which also interact strongly with the random positively ionized impurities. At the insulating side the electrons are all bound in pairs to the ions. On the metallic side free electrons exist which are scattered by ions dressed with electron-pairs and therefore alter the bare scattering potential of the ions. The physics at the metallic side of the transition is argued to be controlled by the classical to quantum transport cross-over leading to the observed non-monotonous dependence of the resistivity on temperature. This few electrons per ion scenario appears to be an experimentally realistic and testable scenario, which can also serve as a starting point for further theoretical analysis of the two-dimensional metal-insulator transition.Comment: 8 pages, revised version, minor change
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