1,705 research outputs found

    On spectral hypergraph theory of the adjacency tensor

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    We study both HH and E/ZE/Z-eigenvalues of the adjacency tensor of a uniform multi-hypergraph and give conditions for which the largest positive HH or ZZ-eigenvalue corresponds to a strictly positive eigenvector. We also investigate when the EE-spectrum of the adjacency tensor is symmetric

    Eigenvalues of the Adjacency Tensor on Products of Hypergraphs

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    Abstract We consider the generalized notions of Cartesian and tensor products on m-uniform hypergraphs. The adjacency tensor is analogous to the adjacency matrix and two different notions of eigenvalues of the adjacency tensor on the products of hypergraphs are studied. The eigenvalues and E-eigenvalues of the adjacency tensor of the Cartesian and tensor products of two hypergraphs in relation to the E-eigenvalues and eigenvalues of the adjacency tensor of the factors are considered. Mathematics Subject Classification: 15A18, 15A69, 05C50, 05C65 Keywords: hypergraph, adjacency tensor, spectral theory of hypergraphs Basic Definitions We begin this paper with some basic definitions from higher order multidimensional tensors. These are standard definitions used in Let R be the real field; we consider an m-order n dimensional tensor A consisting of n m entries in R: A = (a i 1 ···im ), a i 1 ···im ∈ R, 1 ≤ i 1 , . . . , i m ≤ n

    Identification of a Phosphorylation Site for Calcium/Calmodulindependent Protein Kinase II in the NR2B Subunit of the N-Methyl-D-aspartate Receptor

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    The N-methyl-D-aspartate (NMDA) subtype of excitatory glutamate receptors plays critical roles in embryonic and adult synaptic plasticity in the central nervous system. The receptor is a heteromultimer of core subunits, NR1, and one or more regulatory subunits, NR2A-D. Protein phosphorylation can regulate NMDA receptor function (Lieberman, D. N., and Mody, I. (1994) Nature 369, 235-239; Wang, Y. T., and Salter, M. W. (1994) Nature 369, 233-235; Wang, L.-Y., Orser, B. A., Brautigan, D. L., and MacDonald, J. F. (1994) Nature 369, 230-232). Here we identify a major phosphorylation site on subunit NR2B that is phosphorylated by Ca2+/calmodulin-dependent protein kinase II (CaM kinase II), an abundant protein kinase located at postsynaptic sites in glutamatergic synapses. For the initial identification of the site, we constructed a recombinant fusion protein containing 334 amino acids of the C terminus of the NR2B subunit and phosphorylated it with CaM kinase II in vitro. By peptide mapping, automated sequencing, and mass spectrometry, we identified the major site of phosphorylation on the fusion protein as Ser-383, corresponding to Ser-1303 of full-length NR2B. The Km for phosphorylation of this site in the fusion protein was ~50 nM, much lower than that of other known substrates for CaM kinase II, suggesting that the receptor is a high affinity substrate. We show that serine 1303 in the full-length NR2B and/or the cognate site in NR2A is a major site of phosphorylation of the receptor both in the postsynaptic density fraction and in living hippocampal neurons

    How accurate is patients' anatomical knowledge: a cross-sectional, questionnaire study of six patient groups and a general public sample

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    <p>Abstract</p> <p>Background</p> <p>Older studies have shown that patients often do not understand the terms used by doctors and many do not even have a rudimentary understanding of anatomy. The present study was designed to investigate the levels of anatomical knowledge of different patient groups and the general public in order to see whether this has improved over time and whether patients with a specific organ pathology (e.g. liver disease) have a relatively better understanding of the location of that organ.</p> <p>Methods</p> <p>Level of anatomical knowledge was assessed on a multiple-choice questionnaire, in a sample of 722 participants, comprising approximately 100 patients in each of 6 different diagnostic groups and 133 in the general population, using a between-groups, cross-sectional design. Comparisons of relative accuracy of anatomical knowledge between the present and earlier results, and across the clinical and general public groups were evaluated using Chi square tests. Associations with age and education were assessed with the Pearson correlation test and one-way analysis of variance, respectively.</p> <p>Results</p> <p>Across groups knowledge of the location of body organs was poor and has not significantly improved since an earlier equivalent study over 30 years ago (χ<sup>2 </sup>= 0.04, df = 1, ns). Diagnostic groups did not differ in their overall scores but those with liver disease and diabetes were more accurate regarding the location of their respective affected organs (χ<sup>2 </sup>= 18.10, p < 0.001, df = 1; χ<sup>2 </sup>= 10.75, p < 0.01, df = 1). Age was significantly negatively correlated (r = -0.084, p = 0.025) and education was positively correlated with anatomical knowledge (F = 12.94, p = 0.000). Although there was no overall gender difference, women were significantly better at identifying organs on female body outlines.</p> <p>Conclusion</p> <p>Many patients and general public do not know the location of key body organs, even those in which their medical problem is located, which could have important consequences for doctor-patient communication. These results indicate that healthcare professionals still need to take care in providing organ specific information to patients and should not assume that patients have this information, even for those organs in which their medical problem is located.</p

    Collaboration With Deaf Communities to Conduct Accessible Health Surveillance

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    Introduction Populations of deaf sign language users experience health disparities unmeasured by current public health surveillance. Population-specific health data are necessary to collaboratively identify health priorities and evaluate interventions. Standardized, reproducible, and language-concordant data collection in sign language is impossible via written or telephone surveys. Methods Deaf and hearing researchers, community members, and other stakeholders developed a broad computer-based health survey based on the telephone-administered Behavioral Risk Factor Surveillance System. They translated survey items from English to sign language, evaluated the translations, and filmed the survey items for inclusion in their custom software. They initiated the second Rochester Deaf Health Survey in 2013 (n=211). Analyses (conducted in 2015) compared Rochester Deaf Health Survey 2013 findings with those of the Behavioral Risk Factor Surveillance System with the general adult population in the same community (2012, n=1,816). Results The Rochester Deaf Health Survey 2013 participants’ mean age was 44.7 (range, 18—87) years. Most were deaf since birth or early childhood (87.1%) and highly educated (53.6% with ≥4 years of college). The median household income was \u3c $35,000. The prevalence of current smokers was low (8.1%). Nearly all (93.8%) reported having health insurance, yet barriers to appropriate health care were evident, with high emergency department use (16.2% with two or more past-year visits) and 22.7% forgoing needed health care in the past year because of cost. Conclusions Community-engaged research with deaf populations identifies strengths and priorities, providing essential information otherwise missing from existing public health surveillance, and forming a foundation for collaborative dissemination to facilitate broader inclusion of deaf communities

    Human CLEC9A antibodies deliver Wilms' tumor 1 (WT1) antigen to CD141+ dendritic cells to activate naïve and memory WT1‐specific CD8+ T cells

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    Objectives Vaccines that prime Wilms' tumor 1 (WT1)‐specific CD8+ T cells are attractive cancer immunotherapies. However, immunogenicity and clinical response rates may be enhanced by delivering WT1 to CD141+ dendritic cells (DCs). The C‐type lectin‐like receptor CLEC9A is expressed exclusively by CD141+ DCs and regulates CD8+ T‐cell responses. We developed a new vaccine comprising a human anti‐CLEC9A antibody fused to WT1 and investigated its capacity to target human CD141+ DCs and activate naïve and memory WT1‐specific CD8+ T cells. Methods WT1 was genetically fused to antibodies specific for human CLEC9A, DEC‐205 or β‐galactosidase (untargeted control). Activation of WT1‐specific CD8+ T‐cell lines following cross‐presentation by CD141+ DCs was quantified by IFNγ ELISPOT. Humanised mice reconstituted with human immune cell subsets, including a repertoire of naïve WT1‐specific CD8+ T cells, were used to investigate naïve WT1‐specific CD8+ T‐cell priming. Results The CLEC9A‐WT1 vaccine promoted cross‐presentation of WT1 epitopes to CD8+ T cells and mediated priming of naïve CD8+ T cells more effectively than the DEC‐205‐WT1 and untargeted control‐WT1 vaccines. Conclusions Delivery of WT1 to CD141+ DCs via CLEC9A stimulates CD8+ T cells more potently than either untargeted delivery or widespread delivery to all Ag‐presenting cells via DEC‐205, suggesting that cross‐presentation by CD141+ DCs is sufficient for effective CD8+ T‐cell priming in humans. The CLEC9A‐WT1 vaccine is a promising candidate immunotherapy for malignancies that express WT1

    New insights into Eastern Beringian mortuary behavior: A terminal Pleistocene double infant burial at Upward Sun River

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    Here we report on the discovery of two infant burials dating to 11,500 calibrated years (cal) B.P. at the Upward Sun River site in central Alaska. The infants were interred in a pit feature with associated organic and lithic grave goods, including the earliest known North American hafted bifaces with decorated antler foreshafts. Skeletal and dental analyses indicate that Individual 1 died shortly after birth and Individual 2 was a late-term fetus, making these the youngest-aged late Pleistocene individuals known for the Americas and the only known prenate, offering, to our knowledge, the first opportunity to explore mortuary treatment of the youngest members of a terminal Pleistocene North American population. This burial was situated 40 cm directly below a cremated 3-y-old child previously discovered in association with a central hearth of a residential feature. The burial and cremation are contemporaneous, and differences in body orientation, treatment, and associated grave goods within a single feature and evidence for residential occupation between burial episodes indicate novel mortuary behaviors. The human remains, grave goods, and associated fauna provide rare direct data on organic technology, economy, seasonality of residential occupations, and infant/child mortality of terminal Pleistocene Beringians

    Towards a methodology for cluster searching to provide conceptual and contextual "richness" for systematic reviews of complex interventions: case study (CLUSTER)

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    Background Systematic review methodologies can be harnessed to help researchers to understand and explain how complex interventions may work. Typically, when reviewing complex interventions, a review team will seek to understand the theories that underpin an intervention and the specific context for that intervention. A single published report from a research project does not typically contain this required level of detail. A review team may find it more useful to examine a “study cluster”; a group of related papers that explore and explain various features of a single project and thus supply necessary detail relating to theory and/or context. We sought to conduct a preliminary investigation, from a single case study review, of techniques required to identify a cluster of related research reports, to document the yield from such methods, and to outline a systematic methodology for cluster searching. Methods In a systematic review of community engagement we identified a relevant project – the Gay Men’s Task Force. From a single “key pearl citation” we conducted a series of related searches to find contextually or theoretically proximate documents. We followed up Citations, traced Lead authors, identified Unpublished materials, searched Google Scholar, tracked Theories, undertook ancestry searching for Early examples and followed up Related projects (embodied in the CLUSTER mnemonic). Results Our structured, formalised procedure for cluster searching identified useful reports that are not typically identified from topic-based searches on bibliographic databases. Items previously rejected by an initial sift were subsequently found to inform our understanding of underpinning theory (for example Diffusion of Innovations Theory), context or both. Relevant material included book chapters, a Web-based process evaluation, and peer reviewed reports of projects sharing a common ancestry. We used these reports to understand the context for the intervention and to explore explanations for its relative lack of success. Additional data helped us to challenge simplistic assumptions on the homogeneity of the target population. Conclusions A single case study suggests the potential utility of cluster searching, particularly for reviews that depend on an understanding of context, e.g. realist synthesis. The methodology is transparent, explicit and reproducible. There is no reason to believe that cluster searching is not generalizable to other review topics. Further research should examine the contribution of the methodology beyond improved yield, to the final synthesis and interpretation, possibly by utilizing qualitative sensitivity analysis
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