11,815 research outputs found

    Seymour's second neighborhood conjecture for tournaments missing a generalized star

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    Seymour's Second Neighborhood Conjecture asserts that every digraph (without digons) has a vertex whose first out-neighborhood is at most as large as its second out-neighborhood. We prove its weighted version for tournaments missing a generalized star. As a consequence the weighted version holds for tournaments missing a sun, star, or a complete graph.Comment: Accepted for publication in Journal of Graph Theory in 24 June 201

    Mouse cytoplasmic dynein intermediate chains: identification of new isoforms, alternative splicing and tissue distribution of transcripts

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    BACKGROUND: Intracellular transport of cargoes including organelles, vesicles, signalling molecules, protein complexes, and RNAs, is essential for normal function of eukaryotic cells. The cytoplasmic dynein complex is an important motor that moves cargos along microtubule tracks within the cell. In mammals this multiprotein complex includes dynein intermediate chains 1 and 2 which are encoded by two genes, Dync1i1 and Dync1i2. These proteins are involved in dynein cargo binding and dynein complexes with different intermediate chains bind to specific cargoes, although the mechanisms to achieve this are not known. The DYNC1I1 and DYNC1I2 proteins are translated from different splice isoforms, and specific forms of each protein are essential for the function of different dynein complexes in neurons. METHODOLOGY/PRINCIPAL FINDINGS: Here we have undertaken a systematic survey of the dynein intermediate chain splice isoforms in mouse, basing our study on mRNA expression patterns in a range of tissues, and on bioinformatics analysis of mouse, rat and human genomic and cDNA sequences. We found a complex pattern of alternative splicing of both dynein intermediate chain genes, with maximum complexity in the embryonic and adult nervous system. We have found novel transcripts, including some with orthologues in human and rat, and a new promoter and alternative non-coding exon 1 for Dync1i2. CONCLUSIONS/SIGNIFICANCE: These data, including the cloned isoforms will be essential for understanding the role of intermediate chains in the cytoplasmic dynein complex, particularly their role in cargo binding within individual tissues including different brain regions

    A Statistical View of Learning in the Centipede Game

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    In this article we evaluate the statistical evidence that a population of students learn about the sub-game perfect Nash equilibrium of the centipede game via repeated play of the game. This is done by formulating a model in which a player's error in assessing the utility of decisions changes as they gain experience with the game. We first estimate parameters in a statistical model where the probabilities of choices of the players are given by a Quantal Response Equilibrium (QRE) (McKelvey and Palfrey, 1995, 1996, 1998), but are allowed to change with repeated play. This model gives a better fit to the data than similar models previously considered. However, substantial correlation of outcomes of games having a common player suggests that a statistical model that captures within-subject correlation is more appropriate. Thus we then estimate parameters in a model which allows for within-player correlation of decisions and rates of learning. Through out the paper we also consider and compare the use of randomization tests and posterior predictive tests in the context of exploratory and confirmatory data analyses

    How do factors of sociodemographic, health literacy and dementia experience influence carers' knowledge of dementia?

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    BACKGROUND: Dementia is a life limiting disease following a progressive trajectory. As carers often become key decision makers, their knowledge of dementia will have health implications for the person living with dementia as well as carer’s psychological wellbeing. AIM: To explore how sociodemographic factors, health literacy and dementia experience influence family carers knowledge about dementia. METHOD: In this cross-sectional, mixed methods study, we interviewed 150 family carers and assessed their dementia knowledge using the Dementia Knowledge Assessment Scale (DKAS). Linear regression analyses were used to examine whether health literacy, previous experiences of dementia, support group attendance and sociodemographic characteristics predicted knowledge. Sixteen carers also completed qualitative interviews which explored unmet information needs. Transcripts and field notes were thematically analysed. RESULTS: Most participants were partners (47%) or adult children (48%) and cared for someone with severe (32%) or moderate (43%) dementia. Mean DKAS scores were 34.8/50 (SD = 7.0, range = 17–48) reflecting 8/25 incorrect answers. Backwards elimination regression found greater dementia knowledge was associated with greater health literacy for appraising information (coef 3.48, 95% CI (1.38, 5.58); p = 0.001) and more years of education (coef 0.39, 95% CI (0.12, 0.65); p = 0.004). Although not significant, knowledge was slightly lower in those who attended a support group, and a trend was found between ability to understand health information and knowledge. Only 39% accurately identified dementia as life shortening, indicating notable gaps in knowledge. Four qualitative themes were identified; arm yourself with information, ability to steer through information, other experience of dementia can be helpful and the importance of relationships with health care professionals. CONCLUSIONS: In an information age, vast amounts of information are available, but this can bring difficulties. Carers with more years of education and higher health literacy knew more about dementia. Professionals should consider how carers with lower health literacy can be supported through provision of timely, relevant information

    Exploring how family carers of a person with dementia manage pre-death grief: A mixed methods study

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    Objectives Many family carers of a person with dementia experience pre-death grief. We aimed to identify strategies that help carers manage pre-death grief. We hypothesised that emotion and problem focussed styles would be associated with lower, and dysfunctional coping with higher grief intensity. Methods Mixed methods observational study using structured and semi-structured interviews with 150 family carers of people with dementia living at home or in a care home. Most participants were female (77%), caring for a parent (48%) or partner/spouse (47%) with mild (25%), moderate (43%) or severe (32%) dementia. They completed the Marwit-Meuser Caregiver Grief Inventory Short Form and the Brief Coping Orientation to Problems Experienced (Brief-COPE) questionnaire. We asked carers to identify strategies used for managing grief. We recorded field notes for 150 interviews and audio-recorded additional interviews with a sub-sample of 16 participants. Results Correlations indicated that emotion-oriented coping was associated with lower grief (R = −0.341), and dysfunctional coping with higher grief (R = 0.435), with a small association with problem-focused strategies (R = −0.109), partly supporting our hypothesis. Our qualitative themes broadly match the three Brief-COPE styles. Unhelpful strategies of denial and avoidance align with dysfunctional coping strategies. Psychological strategies (including acceptance and humour) and seeking support were consistent with emotion-focused strategies, but we did not identify a theme relating to problem-focused strategies. Conclusion Most carers identified multiple strategies for processing grief. Carers could readily identify supports and services that they found helpful for managing pre-death grief, yet current services appear under-resourced to meet growing demand. (ClinicalTrials.gov ID: NCT03332979)

    Phototesting and photoprotection in LE

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    Photosensitivity and induction of skin lesions following UV radiation is a common problem of patients with cutaneous and systemic forms of lupus erythematosus. The detrimental effect of UV radiation to patients with lupus erythematosus was already recognized in the last century. Skin lesions can now be provoked under standardized conditions allowing the diagnosis and classification of patients with photosensitive disorders. The aim of this review is to give an overview on the history, test procedure and test results in patients with lupus erythematosus

    Evaluating Future Water Availability in Texas through the Lens of a Data-Driven Approach Leveraged with CMIP6 General Circulation Models

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    Climate change is escalating the frequency and intensity of extreme precipitation events, significantly influencing the spatial and temporal distributions of water resources. This is particularly evident in Texas, a rapidly growing state with a pronounced west-east gradient in water supply. This study utilizes Coupled Model Intercomparison Project Phase 6 (CMIP6) data and data-driven methodology to improve projections of Texas\u27s future water resources, focusing on actual evapotranspiration (AET) and water availability through enhanced Multi-Model Ensembles. The results reveal that the data-driven model significantly outperforms the CMIP5 and CMIP6 models across all skill metrics, underscoring the potential of data-driven methodologies in advancing climate science. Furthermore, the study provides an in-depth analysis of the projected changes in net water availability (NWA) and estimated water demand for different regions in Texas over the next six decades from 2015 to 2074, which reveal fluctuating patterns of water stress, with the regions (nine out of sixteen water planning regions in Texas, especially for the most populated regions) poised for heightened challenges in reconciling water demand and availability. While increasing trends are found in precipitation, AET, and NWA for the northern region of Texas based on SSP2–4.5, decreasing trends are found over the southern region for all three parameters based on SSP5–8.5. These findings underscore the importance of factoring both spatial and temporal variations in water availability and demand for effective water management strategies and the need for adaptive water management strategies for the changing water availability scenarios

    Electron-impact broadening of the 3s-3p lines in low-Z Li-like ions

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    The collisional electron-impact line widths of the 3s-3p transitions in Li-like ions from B III to Ne VIII are calculated with the convergent close-coupling (CCC) method from the atomic collision theory. The elastic and inelastic contributions to the line broadening and their Z-scaling are discussed in detail, and comparisons with recent experimental and theoretical results are also presented. It is found that similar to our previous study of line broadening in Be-like ions, the difference between experimental and CCC results monotonically increases with the spectroscopic charge of an ion.Comment: 23 pages, 8 figures, 1 table. To be published in JQSR

    Finite-Size Effects and Scaling for the Thermal QCD Deconfinement Phase Transition within the Exact Color-Singlet Partition Function

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    We study the finite-size effects for the thermal QCD Deconfinement Phase Transition (DPT), and use a numerical finite size scaling analysis to extract the scaling exponents characterizing its scaling behavior when approaching the thermodynamic limit. For this, we use a simple model of coexistence of hadronic gas and color-singlet Quark Gluon Plasma (QGP) phases in a finite volume. The Color-Singlet Partition Function (CSPF) of the QGP cannot be exactly calculated and is usually derived within the saddle point approximation. When we try to do calculations with such an approximate CSPF, a problem arises in the limit of small temperatures and/or volumes (VT3<<1), requiring then additional approximations if we want to carry out calculations. We propose in this work a new method for an accurate calculation of any quantity of the finite system, without explicitly calculating the CSPF itself and without any approximation. By probing the behavior of some useful thermodynamic response functions on the hole range of temperature, it turns out that in a finite size system, all singularities in the thermodynamic limit are smeared out and the transition point is shifted away. A numerical finite size scaling analysis of the obtained data allows us to determine the scaling exponents of the QCD DPT. Our results expressing the equality between their values and the space dimensionality is a consequence of the singularity characterizing a first order phase transition and agree very well with the predictions of other FSS theoretical approaches and with the results of both lattice QCD and Monte Carlo models calculations.Comment: 09 pages, 11 Postscript figure
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