350 research outputs found

    Positive maps, positive polynomials and entanglement witnesses

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    We link the study of positive quantum maps, block positive operators, and entanglement witnesses with problems related to multivariate polynomials. For instance, we show how indecomposable block positive operators relate to biquadratic forms that are not sums of squares. Although the general problem of describing the set of positive maps remains open, in some particular cases we solve the corresponding polynomial inequalities and obtain explicit conditions for positivity.Comment: 17 pages, 1 figur

    From Porciones to Colonias: Curriculum Development in K-12 Education--Methodology and Program Development

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    The 2012 National Endowment for the Humanities- sponsored “From Porciones to Colonias: Inserting the “Hispanic” in a Hispanic Serving Institution through Curriculum Innovation” brought together faculty at the largest Hispanic Serving Institution in Texas, the University of Texas-Pan American (UTPA), and public school teachers to create place-based curriculum. Using the natural landscape and cultural history of one of the most dynamic borderlands in the world as the main classroom laboratory, faculty housed in the CHAPS program (Community Historical Archaeology Project with Schools) challenged elementary, middle, and high school teachers in the sciences, social sciences and humanities to create in their students historically literate citizens who are aware of their local cultural and natural history. The following briefly encapsulates the conducted activities

    Understanding the power of the prime minister : structure and agency in models of prime ministerial power

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    Understanding the power of the prime minister is important because of the centrality of the prime minister within the core executive of British government, but existing models of prime ministerial power are unsatisfactory for various reasons. This article makes an original contribution by providing an overview and critique of the dominant models of prime ministerial power, highlighting their largely positivist bent and the related problem of the prevalence of overly parsimonious conceptions of the structural contexts prime ministers face. The central argument the paper makes is that much of the existing literature on prime ministerial power is premised on flawed understandings of the relationship between structure and agency, that this leads to misunderstandings of the real scope of prime ministerial agency, as well as its determinants, and that this can be rectified by adopting a strategic-relational view of structure and agency

    From Porciones to Colonias: The Power of Place and Community-Based Learning in K-12 Education - A Case Study From the Lower Rio Grande Valley of Texas

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    From Porciones to Colonias: The Power of Place- and Community-Based Learning in K-12 Education redefines culturally relevant learning in today’s diverse classroom. By integrating an interdisciplinary approach including: anthropology, archeology, biology, geology, and history the CHAPS Program presents an effective method in supporting teachers of the Rio Grande Valley in creating culturally relevant curriculum, while meeting the demands of state and federal mandates. Sponsored by The National Endowment for the Humanities.https://scholarworks.utrgv.edu/chapspublications/1010/thumbnail.jp

    Power, norms and institutional change in the European Union: the protection of the free movement of goods

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    How do institutions of the European Union change? Using an institutionalist approach, this article highlights the interplay between power, cognitive limits, and the normative order that underpins institutional settings and assesses their impact upon the process of institutional change. Empirical evidence from recent attempts to reinforce the protection of the free movement of goods in the EU suggests that, under conditions of uncertainty, actors with ambiguous preferences assess attempts at institutional change on the basis of the historically defined normative order which holds a given institutional structure together. Hence, path dependent and incremental change occurs even when more ambitious and functionally superior proposals are on offer

    The evolutionary roots of creativity: mechanisms and motivations

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    Funding: MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.We consider the evolution of cognition and the emergence of creative behaviour, in relation to vocal communication. We address two key questions: (i) what cognitive and/or social mechanisms have evolved that afford aspects of creativity?; (ii) has natural and/or sexual selection favoured human behaviours considered ‘creative’? This entails analysis of ‘creativity’, an imprecise construct: comparable properties in non-humans differ in magnitude and teleology from generally agreed human creativity. We then address two apparent problems: (i) the difference between merely novel productions and ‘creative’ ones; (ii) the emergence of creative behaviour in spite of high cost: does it fit the idea that females choose a male who succeeds in spite of a handicap (costly ornament); or that creative males capable of producing a large and complex song repertoire grew up under favourable conditions; or a demonstration of generally beneficial heightened reasoning capacity; or an opportunity to continually reinforce social bonding through changing communication tropes; or something else? We illustrate and support our argument by reference to whale and bird song; these independently evolved biological signal mechanisms objectively share surface properties with human behaviours generally called ‘creative’. Studying them may elucidate mechanisms underlying human creativity; we outline a research programme to do so.PostprintPeer reviewe

    Processive Movement by a Kinesin Heterodimer with an Inactivating Mutation in One Head†

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    ABSTRACT: A single molecule of the motor enzyme kinesin-1 keeps a tight grip on its microtubule track, making tens or hundreds of discrete, unidirectional 8 nm steps before dissociating. This high duty ratio processive movement is thought to require a mechanism in which alternating stepping of the two head domains of the kinesin dimer is driven by alternating, overlapped cycles of ATP hydrolysis by the two heads. The R210K point mutation in Drosophila kinesin heavy chain was reported to disrupt the ability of the enzyme active site to catalyze ATP P-O bond cleavage. We expressed R210K homodimers as well as isolated R210K heads and confirmed that both are essentially inactive. We then coexpressed tagged R210K subunits with untagged wild-type subunits and affinity purified R210K/wild-type heterodimers together with the inactive R210K homodimers. In contrast to the R210K head or homodimer, the heterodimer was a highly active (>50 % of wild-type) microtubule-stimulated ATPase, and the heterodimer displayed high duty ratio processive movement in single-molecule motility experiments. Thus, dimerization of a subunit containing the inactivating mutation with a functional subunit can complement the mutation; this must occur either by lowering or by bypassing kinetic barriers in the ATPase or mechanical cycles of the mutant head. The observations provide support for kinesin-1 gating mechanisms in which one head stimulates the rate of essential processes in the other

    De las porciones a las colonias: La fuerza del aprendizaje con enfoque local y comunitario dentro de la educación desde el preescolar hasta la preparatoria - Un estudio de caso desde El Valle del Río Grande de Texas

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    El proyecto titulado De las porciones a las colonias: la fuerza del aprendizaje con enfoque local y comunitario dentro de la educación desde el preescolar hasta la preparatoria es una iniciativa que redefine la importancia del aprendizaje con relevancia cultural en las aulas escolares de la actualidad, cada vez más diversas en la composición de su alumnado. Mediante la integración de un enfoque interdisciplinar que incluye la Antropología, la Arqueología, la Biología, la Geología y la Historia, el programa CHAPS presenta un método eficiente para brindar apoyo a los profesores de El Valle del Río Grande a la hora de elaborar currículos escolares con relevancia cultural, a la par que se satisfacen los requisitos educativos establecidos a nivel estatal y federal. Patrocinador: The National Endowment for the Humanitieshttps://scholarworks.utrgv.edu/chapspublications/1011/thumbnail.jp

    The Trump foreign policy record and the concept of transformational change

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    While there has been debate about the extent to which US foreign policy has been transformed since President Trumpfirst took office in 2017, the concept of transformational policy change has not been defined with any degree of precision. The purpose of this article is, primarily, to establish such a definition. It does this by drawing upon a number of the literatures that address domestic policy processes, in particular the work of Karl Polanyi, to suggest that transformational change rests upon paradigmatic shifts, the reconfiguration of interests, large scale institutional re-ordering and changed logics. Application of the definition to the Trump foreign policy leads us to conclude that while the Trump foreign policy owes much to the militant internationalism of the Bush years its understanding of nations and“globalism”and abandonment of a defining moral purpose represent, although incipient, partial and variegated, the beginnings of transformational change

    Myosin VI in PC12 cells plays important roles in cell migration and proliferation but not in catecholamine secretion

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    Myosin VI (MVI) is the only known myosin walking towards minus end of actin filaments and is believed to play distinct role(s) than other myosins. We addressed a role of this unique motor in secretory PC12 cells, derived from rat adrenal medulla pheochromocytoma using cell lines with reduced MVI synthesis (produced by means of siRNA). Decrease of MVI expression caused severe changes in cell size and morphology, and profound defects in actin cytoskeleton organization and Golgi structure. Also, significant inhibition of cell migration as well as cell proliferation was observed. Flow cytometric analysis revealed that MVI-deficient cells were arrested in G0/G1 phase of the cell cycle but did not undergo increased senescence as compared with control cells. Also, neither polyploidy nor aneuploidy were detected. Surprisingly, no significant effect on noradrenaline secretion was observed. These data indicate that in PC12 cells MVI is involved in cell migration and proliferation but is not crucial for stimulation-dependent catecholamine release
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