2,676 research outputs found

    Examining Social Desirability Orientation and Alcohol Use Expectations as Factors in Fraternity Drinking

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    Alcohol misuse by members of collegiate fraternal organizations has been cited as a This study examined two constructs, (a) an orientation toward social desirability, and (b) expectations of alcohol use, as factors in fraternity member alcohol consumption. 324 participants from 13 different fraternity chapters at 12 different institutions completed measures of social desirability orientation (Social Desirability Scale; Marlowe & Crowne, 1964) and expectations of alcohol use (Alcohol Expectancy Questionnaire; Brown, Goldman, Inn & Anderson, 1987) and additional demographic information. We found high social desirability orientations, strong expectations for the outcomes of alcohol use, and relationships between these two constructs. Implications for institutional programming and practice, limitations, and future research directions are discussed

    Direct calorimetric measurements of isothermal entropy change on single crystal W-type hexaferrites at the spin reorientation transition

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    We report on the magnetic field induced isothermal entropy change, \Delta s(Ha, T), of W-type ferrite with CoZn substitution. Entropy measurements are performed by direct calorimetry. Single crystals of the composition BaCo0.62_0.62Zn1.38_1.38Fe16_16O27_27, prepared by the flux method, are measured at different fixed temperatures under an applied field perpendicular and parallel to the c axis. At 296 K one deduces a value of K1_1 = 8.7 \times 10^{4} J m−3^-3 for the first anisotropy constant, which is in good agreement with the literature. The spin reorientation transition temperature is estimated to take place between 200 and 220 K

    A Step-by-step Guide to the Realisation of Advanced Optical Tweezers

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    Since the pioneering work of Arthur Ashkin, optical tweezers have become an indispensable tool for contactless manipulation of micro- and nanoparticles. Nowadays optical tweezers are employed in a myriad of applications demonstrating the importance of these tools. While the basic principle of optical tweezers is the use of a strongly focused laser beam to trap and manipulate particles, ever more complex experimental set-ups are required in order to perform novel and challenging experiments. With this article, we provide a detailed step- by-step guide for the construction of advanced optical manipulation systems. First, we explain how to build a single-beam optical tweezers on a home-made microscope and how to calibrate it. Improving on this design, we realize a holographic optical tweezers, which can manipulate independently multiple particles and generate more sophisticated wavefronts such as Laguerre-Gaussian beams. Finally, we explain how to implement a speckle optical tweezers, which permit one to employ random speckle light fields for deterministic optical manipulation.Comment: 29 pages, 7 figure

    Toward a More Functional Analysis of Aggression

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    Given the substantial and oftentimes irreversible human loss resulting from aggressive acts, the need for systematic, treatment-linked assessment of aggression in school-aged children and youth cannot be overstated. Based upon recent research, the authors provide a broadly framed model for the functional analysis of aggression in school-age children and youth. Our model incorporates multi-modal data collection and data triangulation to generate credible hypotheses regarding the function(s) of aggression. Three primary data sources—record review and interviews, naturalistic observation, and analogue assessment—form the cornerstone of the model. Key features of our approach to the assessment of aggression include operational definition(s) of target behavior(s), examination of the environmental context(s) of aggression, and discovery of the function(s) of aggressive behaviors for the individual. Samples of several specific, ready-to-use data collection instruments and a basic description of the assessment procedure are presented. The assessment process assumes that a team of individuals participates in data collection, data analysis, and hypothesis generation

    The Shift in Leadership Styles: Joyful to Toxic

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    Identification of the plastic zone using digital image correlation

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    In this paper Digital Image Correlation (DIC) is used to study the evolution of the plastic zone close to a crack tip. A modified CT-specimen was used in order to fulfill the plane stress condition. The strain field around the crack tip was measured using two cameras and stereo DIC, so that out-of-plane movements are taken into account. Then, the Virtual Fields Method was used to identify the plastic zone, looking at the parts of the specimen which deviates from the linear elastic behavior. With such approach, it was possible to individuate the onset of plasticity close to the crack tip and follow its evolution. A comparison with FEM results is also provided

    Visual stimulation activates ERK in synaptic and somatic compartments of rat cortical neurons with parallel kinetics.

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    BACKGROUND: Extracellular signal-regulated kinase (ERK) signalling pathway plays a crucial role in regulating diverse neuronal processes, such as cell proliferation and differentiation, and long-term synaptic plasticity. However, a detailed understanding of the action of ERK in neurons is made difficult by the lack of knowledge about its subcellular localization in response to physiological stimuli. To address this issue, we have studied the effect of visual stimulation in vivo of dark-reared rats on the spatial-temporal dynamics of ERK activation in pyramidal neurons of the visual cortex. METHODOLOGY/PRINCIPAL FINDINGS: Using immunogold electron microscopy, we show that phosphorylated ERK (pERK) is present in dendritic spines, both at synaptic and non-synaptic plasma membrane domains. Moreover, pERK is also detected in presynaptic axonal boutons forming connections with dendritic spines. Visual stimulation after dark rearing during the critical period causes a rapid increase in the number of pERK-labelled synapses in cortical layers I-II/III. This visually-induced activation of ERK at synaptic sites occurs in pre- and post-synaptic compartments and its temporal profile is identical to that of ERK activation in neuronal cell bodies. CONCLUSIONS/SIGNIFICANCE: Visual stimulation in vivo increases pERK expression at pre- and post-synaptic sites of axo-spinous junctions, suggesting that ERK plays an important role in the local modulation of synaptic function. The data presented here support a model in which pERK can have early and late actions both centrally in the cell nucleus and peripherally at synaptic contacts

    EYE/I AND EYES/WE: REFLEXSIVITY AND INTERSUBECTIVITY IN AFRICAN GLOCAL VISUAL AND AUTO ETHNOGRAPHY

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    This dissertation aims to explore West African transnational experiences in order to further understand how identity markers and politics manifest anxieties for transnational migrants and their movements between America and Africa. It engages and expands contemporary understandings of transnationalism with a focus on generational migrants. Generational migrants are defined as 1.5 through second-generation offspring of African immigrants. For the purposes of this research, "1.5-generation" is defined as an individual who was born in Africa and spent most of their lives in America, while "second-generation" is used to connote an individual who was born in America to African parents. Reflexivity, intersubjectivity, as well as identity negotiation and/or “code switching” are explored to explicate the experiences of generational migrants. Influenced by the theories and arguments of Stuart Hall, John Arthur, Joanna D’Alisera, W. E. B. Dubois, Pnina Motzafi-Haller, Audre Lorde, and Chandra Mohanty, this dissertation argues for a multiplicity and fluidity of identity (i.e.: holding multiple and sometimes contrary communities while constantly moving between continents), but also I am advocating for the possibility of fluidity in the reflexivity as one moves between these identity markers to create epistemological questions, constitute authorship, and expand representation. This argument is explored in each chapter via problematizing familial structures, African Fashion, ethnographic filmmaking, and auto-ethnographic writing. These contributions will transform the conceptualizations of African diasporic identities from one that is historically limited by bicultural formation into one that asserts the complexity of diasporic consciousness, which will construct new texts

    Notes on the complexity of 3-valent graphs in 3-manifolds

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    A theory of complexity for pairs (M,G) with M an arbitrary closed 3-manifold and G a 3-valent graph in M was introduced by the first two named authors, extending the original notion due to Matveev. The complexity c is known to be always additive under connected sum away from the graphs, but not always under connected sum along (unknotted) arcs of the graphs. In this article we prove the slightly surprising fact that if in M there is a sphere intersecting G transversely at one point, and this point belongs to an edge e of G, then e can be canceled from G without affecting the complexity. Using this fact we completely characterize the circumstances under which complexity is additive under connected sum along graphs. For the set of pairs (M,K) with K a knot in M, we also prove that any function that is fully additive under connected sum along knots is actually a function of the ambient manifold only.Comment: 15 pages, 6 figure

    Additively manufactured CuCrZr alloy: improvement of mechanical properties by heat treatment

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    CuCrZr alloy plays a fundamental role for the production of critical components because it is characterized by good thermal and electrical conductivity and by high mechanical strength after precipitation hardening treatment. In the framework of a wider research on the mechanical behaviour of additively manufactured CuCrZr alloy, this study focuses on the effects of heat treatment parameters on the alloy strength. The additive manufacturing process, characterized by very high cooling rates, determines the formation, in the as-built condition, of a supersaturated solid solution. The results obtained reveal that aging temperature and time are critical parameters for improving the mechanical behaviour of CuCrZr alloy which behaves differently than the alloy produced through the use of traditional techniques
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