622 research outputs found

    Regional astrocyte IFN signaling restricts pathogenesis during neurotropic viral infection

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    Type I IFNs promote cellular responses to viruses, and IFN receptor (IFNAR) signaling regulates the responses of endothelial cells of the blood-brain barrier (BBB) during neurotropic viral infection. However, the role of astrocytes in innate immune responses of the BBB during viral infection of the CNS remains to be fully elucidated. Here, we have demonstrated that type I IFNAR signaling in astrocytes regulates BBB permeability and protects the cerebellum from infection and immunopathology. Mice with astrocyte-specific loss of IFNAR signaling showed decreased survival after West Nile virus infection. Accelerated mortality was not due to expanded viral tropism or increased replication. Rather, viral entry increased specifically in the hindbrain of IFNAR-deficient mice, suggesting that IFNAR signaling critically regulates BBB permeability in this brain region. Pattern recognition receptors and IFN-stimulated genes had higher basal and IFN-induced expression in human and mouse cerebellar astrocytes than did cerebral cortical astrocytes, suggesting that IFNAR signaling has brain region–specific roles in CNS immune responses. Taken together, our data identify cerebellar astrocytes as key responders to viral infection and highlight the existence of distinct innate immune programs in astrocytes from evolutionarily disparate regions of the CNS

    Longitudinal patterns in an Arkansas River Valley stream: an Application of the River Continuum Concept

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    The River Continuum Concept (RCC) provides the framework for studying how lotic ecosystems vary from headwater streams to large rivers. The RCC was developed in streams in eastern deciduous forests of North America, but watershed characteristics and land uses differ across ecoregions, presenting unique opportunities to study how predictions of the RCC may differ across regions. Additionally, RCC predictions may vary due to the influence of fishes, but few studies have used fish taxa as a metric for evaluating predictions of the RCC. Our goal was to determine if RCC predictions for stream orders 1 through 5 were supported by primary producer, macroinvertebrate, and fish communities in Cadron Creek of the Arkansas River Valley. We sampled chlorophyll a, macroinvertebrates, and fishes at five stream reaches across a gradient of watershed size. Contrary to RCC predictions, chlorophyll a did not increase in concentration with catchment size. As the RCC predicts, fish and macroinvertebrate diversity increased with catchment size. Shredding and collecting macroinvertebrate taxa supported RCC predictions, respectively decreasing and increasing in composition as catchment area increased. Herbivorous and predaceous fish did not follow RCC predictions; however, surface-water column feeding fish were abundant at all sites as predicted. We hypothesize some predictions of the RCC were not supported in headwater reaches of this system due to regional differences in watershed characteristics and altered resource availability due to land use surrounding sampling sites

    Racial and gender science achievement gaps in secondary education

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    ABSTRACT A substantial disparity exists for academic achievement in science between Black and White primary-school children. A similar gap exists between boys and girls. The extent to which secondary education influences these achievement gaps has not been established. The authors report analyses showing how these science achievement gaps change as a function of secondary education. Analyses of data from a large, nationally representative longitudinal study of academic achievement showed that racial disparities and disparities associated with gender continue to increase throughout high school

    Ant colonies: building complex organizations with minuscule brains and no leaders

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    Thus far the articles in the series JOD calls the “Organization Zoo” have employed the notion of a “zoo” metaphorically to describe an array of human institutions. Here we take the term literally to consider the design of the most complex organizations in the living world beside those of humans, a favorite of insect zoos around the world: ant colonies. We consider individuality and group identity in the functioning of ant organizations; advantages of a flat organization without hierarchies or leaders; self-organization; direct and indirect communication; job specialization; labor coordination; and the role of errors in innovation. The likely value and limitations of comparing ant and human organizations are briefly examined

    Measuring Cognitive Reflection without Maths: Development and Validation fo the Verbal Cognitive Reflection Test

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    The Cognitive Reflection Test (CRT) became popular for its impressive power to predict how well people reason and make decisions. Despite the popularity of the CRT, a major issue complicates its interpretation: the numerical nature of the CRT confounds reflection ability with mathematical ability. We have addressed this issue by developing the Verbal CRT (CRT-V), a novel 10-item measure of cognitive reflection (https://osf.io/xehbv/), using non-mathematical problems with good statistical and psychometric properties and with low familiarity. First, we selected suitable items with relatively low familiarity and optimal difficulty as identified in two different populations (Studies 1 and 2) and with high content validity as judged by an expert panel (Study 3). Second, we demonstrated good criterion and construct validity for the test in different populations with a wide range of variables (Studies 4-6, 8) and a good internal consistency and test-retest reliability (Study 7). The Verbal CRT was less associated with math anxiety, objective and subjective numeracy than the original CRT and it was test equivalent across gender, age groups and administration setting. In contrast with the original CRT (Hedge’s g = 0.29, 95% CI[0.17, 0.40]), the Verbal CRT showed no gender differences (Hedge’s g = -0.06, 95% CI[-0.18, 0.06]). The Verbal CRT can complement existing, numerical, tests of cognitive reflection

    Coinductive subtyping for abstract compilation of object-oriented languages into Horn formulas

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    In recent work we have shown how it is possible to define very precise type systems for object-oriented languages by abstractly compiling a program into a Horn formula f. Then type inference amounts to resolving a certain goal w.r.t. the coinductive (that is, the greatest) Herbrand model of f. Type systems defined in this way are idealized, since in the most interesting instantiations both the terms of the coinductive Herbrand universe and goal derivations cannot be finitely represented. However, sound and quite expressive approximations can be implemented by considering only regular terms and derivations. In doing so, it is essential to introduce a proper subtyping relation formalizing the notion of approximation between types. In this paper we study a subtyping relation on coinductive terms built on union and object type constructors. We define an interpretation of types as set of values induced by a quite intuitive relation of membership of values to types, and prove that the definition of subtyping is sound w.r.t. subset inclusion between type interpretations. The proof of soundness has allowed us to simplify the notion of contractive derivation and to discover that the previously given definition of subtyping did not cover all possible representations of the empty type

    Gender-based food intake stereotype scale (GBFISS) for adolescents: development and psychometric evaluation

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    Objective. The study aimed to develop and test the validity and reliability of a gender-based food intake stereotype scale (GBFISS) to further the understanding of gender stereotype influences on food intake. Design. Two cross-sectional studies were conducted among adolescents. In the first one (n = 611), exploratory and confirmatory factor analyses were performed on subsamples to identify and cross-validate the scale’s structure. Evidence of concurrent validity (correlation with sexism) was also examined. In the second study (n = 813), confirmatory factor analysis was conducted to confirm the scale’s dimensionality on a different sample. Further evidence of construct validity (correlations with food intake and social desirability) was examined. Invariance was tested for different features as well. Main outcome. The Gender-Based Food Intake Stereotype Scale. Results. Factor analyses on the first and second studies helped identify and confirm the GBFISS as a three-dimensional scale. The studies also provided evidence of construct validity. Support for invariance by gender and age was found, and reliability was acceptable. Conclusion. The evidence suggests that the GBFISS is valid and reliable. Further research is recommended. The contribution of gender stereotypes, as measured by the GBFISS, to well-established health behavior models should be examined.Ministerio de Salud/[DM-FG-4854-14 and DM-FG.1748-2018]//Costa RicaFundación INCIENSA/[]/FUNIN/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Instituto de Investigaciones Psicológicas (IIP

    Re-evaluating the Self-Report Habit Index: the cases of Physical Activity and Snacking habits

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    Objective. The Self-Report Habit Index (SRHI) was originally reported as one-dimensional (Verplanken and Orbell, 2003). Nevertheless, habit has been described as characterized by several features, and one-dimensional models for the SRHI have shown poor fit. Therefore, we aimed to compare multi-dimensional models with a one-dimension model in both snacking and physical activity habits, besides examining further instrument characteristics. Design. A cross-sectional study was conducted with high school and university students (n = 555). Main outcome measure. The SRHI adapted for physical activity and for snaking habits was applied at one single time. Results. Nested models with one factor, two factors, and three factors were compared. Then, a hierarchical second-order model was tested, and further validity issues, as well as invariance between habits, were examined. Three-dimensional models represented a better fit for both habits. However, fit was still non-adequate in the snacking version. Also, discriminant validity concerns raised for the physical activity SRHI. Also, invariance between the snacking and the physical activity versions was not confirmed. Conclusions. Considering the SRHI as composed by the dimensions of “lack of awareness”, “lack of control”, and “history of behavioural repetition” seems to be more accurate. Nevertheless, our findings suggest that further research is needed.Universidad de Costa Rica/[723-B7-306]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Instituto de Investigaciones Psicológicas (IIP

    Assessing young people's political engagement: a critical and systematic literature review of the instruments used to measure political engagement

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    Over the past few decades, there has been an increasing interest in understanding youth political engagement. However, it has been argued that the instruments used to assess the concept often lack adequate validation, and this is important as this practice may result in biased statistical conclusions. Consequently, the main aim of the present study was to systematically review, summarize, and critique the extant research evidence on the development of psychometric instruments that assess young people’s political engagement. Following a systematic review of the literature, seven instruments were identified that were both valid and reliable, but none explicitly assessed young people’s political engagement. Instead, they considered broad concepts and/or dimensions related to political engagement. Emphasising the lack of statistically robust standardised measurement tools that empirically assess young people’s political engagement, the available evidence confirms the pressing need to adopt a robust psychometric approach to assess political engagement in youth
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