4,839 research outputs found

    Effects of similarity and tourist status on prosocial behavior: a field study in Spain

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    Male and female participants in four cities across Southern and Northern Spain were approached by a male tourist-confederate and were given an opportunity to act in a helpful or unhelpful manner. The factor of interest was similarity to the helper, which was manipulated via spoken language (English vs. Spanish) and soccer team affiliation (in-group vs. out-group jersey). To investigate anti-American sentiment, confederate nationality (American or Canadian) was also manipulated. Prosocial behavior was operationally defined as granting use of a cell phone to a lost tourist. Consistent with the similarity hypothesis, it was found that conditions in which the confederate was most similar to the participant (Spanish speakers wearing in-group jerseys) elicited the highest rate of helping, whereas conditions in which he was least similar (English speakers wearing out-group jerseys) elicited the lowest rate of helping. As hypothesized, there were no observed treatment differences between Canadians and Americans

    Properties of Resonating-Valence-Bond Spin Liquids and Critical Dimer Models

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    We use Monte Carlo simulations to study properties of Anderson's resonating-valence-bond (RVB) spin-liquid state on the square lattice (i.e., the equal superposition of all pairing of spins into nearest-neighbor singlet pairs) and compare with the classical dimer model (CDM). The latter system also corresponds to the ground state of the Rokhsar-Kivelson quantum dimer model at its critical point. We find that although spin-spin correlations decay exponentially in the RVB, four-spin valence-bond-solid (VBS) correlations are critical, qualitatively like the well-known dimer-dimer correlations of the CDM, but decaying more slowly (as 1/ra1/r^a with a1.20a \approx 1.20, compared with a=2a=2 for the CDM). We also compute the distribution of monomer (defect) pair separations, which decay by a larger exponent in the RVB than in the CDM. We further study both models in their different winding number sectors and evaluate the relative weights of different sectors. Like the CDM, all the observed RVB behaviors can be understood in the framework of a mapping to a "height" model characterized by a gradient-squared stiffness constant KK. Four independent measurements consistently show a value KRVB1.6KCDMK_{RVB} \approx 1.6 K_{CDM}, with the same kinds of numerical evaluations of KCDMK_{CDM} give results in agreement with the rigorously known value KCDM=π/16K_{CDM}=\pi/16. The background of a nonzero winding number gradient W/LW/L introduces spatial anisotropies and an increase in the effective K, both of which can be understood as a consequence of anharmonic terms in the height-model free energy, which are of relevance to the recently proposed scenario of "Cantor deconfinement" in extended quantum dimer models. We also study ensembles in which fourth-neighbor (bipartite) bonds are allowed, at a density controlled by a tunable fugacity, resulting (as expected) in a smooth reduction of K.Comment: 26 pages, 21 figures. v3: final versio

    Фармакогностический анализ сабельника болотного

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    АВТОРЕФЕРАТЫ ДИССЕРТАЦИЙБИОЛОГИЧЕСКИ АКТИВНЫЕ ВЕЩЕСТВАЛЕКАРСТВЕННЫЕ СРЕДСТВАРАСТЕНИЯ ЛЕКАРСТВЕННЫЕРАСТИТЕЛЬНОЕ ЛЕКАРСТВЕННОЕ СЫРЬЕСАБЕЛЬНИК БОЛОТНЫЙФАРМАКОГНОЗИЯФАРМАКОЛОГИЯФИТОПРЕПАРАТЫХИМИЯ ФАРМАЦЕВТИЧЕСКА

    Seismic base isolation : a five-story building example

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    Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1999.Includes bibliographical references (leaves 58-59).by Erik Anders Nelson.M.Eng

    The Effect of Columnar Disorder on the Superconducting Transition of a Type-II Superconductor in Zero Applied Magnetic Field

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    We investigate the effect of random columnar disorder on the superconducting phase transition of a type-II superconductor in zero applied magnetic field using numerical simulations of three dimensional XY and vortex loop models. We consider both an unscreened model, in which the bare magnetic penetration length is approximated as infinite, and a strongly screened model, in which the magnetic penetration length is of order the vortex core radius. We consider both equilibrium and dynamic critical exponents. We show that, as in the disorder free case, the equilibrium transitions of the unscreened and strongly screened models lie in the same universality class, however scaling is now anisotropic. We find for the correlation length exponent ν=1.2±0.1\nu=1.2\pm 0.1, and for the anisotropy exponent ζ=1.3±0.1\zeta=1.3\pm 0.1. We find different dynamic critical exponents for the unscreened and strongly screened models.Comment: 30 pages 12 ps figure

    Contactless Transport and Mixing of Liquids on Self-Sustained Sublimating Coatings

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    The controlled handling of liquids and colloidal suspensions as they interact with surfaces, targeting a broad palette of related functionalities, is of great importance in science, technology, and nature. When small liquid volumes need to be processed in microfluidic devices, contamination on the solid-liquid interface and loss of liquid due to adhesion on the transport channels are two very common problems that can significantly alter the process outcome, e.g. the chemical reaction efficiency, or the purity and the final concentrations of a suspension. It is therefore no surprise that both levitation and minimal contact transport methods including non wetting surfaces have been developed to minimize the interactions between liquids and surfaces. Here we demonstrate contactless surface levitation and transport of liquid drops, realized by harnessing and sustaining the natural sublimation of a solid carbon dioxide-coated substrate to generate a continuous supporting vapor layer. The capability and limitations of this technique in handling liquids of extreme surface tension and kinematic viscosity values are investigated both experimentally and theoretically. The sublimating coating is capable of repelling many viscous and low surface tension liquids, colloidal suspensions, and non-Newtonian fluids as well, displaying outstanding omniphobic properties. Finally, we demonstrate how sublimation can be used for liquid transport, mixing and drop coalescence, with a sublimating layer coated on an underlying substrate with prefabricated channels, conferring omniphobicity with a simple physical approach, rather than a chemical one

    Topographical and Cell Type-Specific Connectivity of Rostral and Caudal Forelimb Corticospinal Neuron Populations

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    Corticospinal neurons (CSNs) synapse directly on spinal neurons, a diverse assortment of cells with unique structural and functional properties necessary for body movements. CSNs modulating forelimb behavior fractionate into caudal forelimb area (CFA) and rostral forelimb area (RFA) motor cortical populations. Despite their prominence, the full diversity of spinal neurons targeted by CFA and RFA CSNs is uncharted. Here, we use anatomical and RNA sequencing methods to show that CSNs synapse onto a remarkably selective group of spinal cell types, favoring inhibitory populations that regulate motoneuron activity and gate sensory feedback. CFA and RFA CSNs target similar spinal neuron types, with notable exceptions that suggest that these populations differ in how they influence behavior. Finally, axon collaterals of CFA and RFA CSNs target similar brain regions yet receive highly divergent inputs. These results detail the rules of CSN connectivity throughout the brain and spinal cord for two regions critical for forelimb behavior

    Evaluation of Complex Whole-School Interventions: Methodological and Practical Considerations

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    Evaluating the impact of complex whole-school interventions (CWSIs) is challenging. However, what evidence there is suggests that school leadership and other elements of whole-school contexts are important for pupils’ attainment (Leithwood et al., 2006), suggesting that interventions aimed at changing these have significant potential to improve pupil outcomes. Furthermore, strong leadership is likely important for the effective implementation of many interventions funded by the EEF since even class-level or targeted programmes are more likely to work best within supportive and effective settings. We therefore welcome the EEF’s commitment to exploring the issues inherent in evaluating CWSIs. Developing design and practice for evaluations of this type of intervention, focusing on the issues of complexity and managing change across a whole school, increases the scope of projects of which the EEF may confidently fund evaluations. In this document, we provide key messages for EEF evaluators on how to get the most out of evaluations of CWSIs, including considerations for both design and implementation. As far as possible, our suggestions aim to be practical steps that evaluators can implement immediately. A number of issues, and points 13 and 14 below in particular, require either further investigation or decisions from the EEF

    The common cuckoo is an effective indicator of high bird species richness in Asia and Europe

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    AbstractCommon cuckoo Cuculus canorus is a charismatic bird species with a dominant presence in human culture: from folklore legends to nowadays there is evidence of cuckoos being a prime candidate as a surrogate of bird diversity. Recent studies demonstrated that the cuckoo can predict hotspots of taxonomic diversity and functional diversity of bird communities in European countries. In this study, we demonstrated that the cuckoo is an excellent bioindicator at multi-spatial scale, extending cuckoo surrogacy from Europe to Asia. Even using three different survey methods (transect, square, point counts), comparing the new findings with results of our research in Europe, sites where the cuckoo is present were characterized by greater species richness, while the cuckoo was absent from sites with low species richness. The goodness of fit of models based on point counts ranged between 71 and 92%. Furthermore, the cuckoo population trend mirrors the average population trend and climate suitability of overall bird communities in Europe. The common cuckoo is therefore a suitable intercontinental bioindicator of hotspots of bird richness, even under climate change scenarios or in areas where the species co-occurs with other cuckoo species, opening a new avenue for standardized citizen science on bird biodiversity surveys worldwide.</jats:p
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