1,424 research outputs found

    Theories of practice and geography

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    Recent developments in theories of practice have seen place and space taken explicitly into account. In particular, THEODORE SCHATZKI’s ‘site ontology’ offers distinctive but as yet under-explored means of engaging with human geographies. By giving ontological priority to practices as constitutive of the social, this kind of practice theory provides an integrative conceptual framework that enables the analysis of diverse phenomena in relation to each other, over space and time, as they are constituted through practices. This article develops an outline agenda for bringing theories of practice, and particularly SCHATZKI’s ‘site ontology’, together with geographical inquiry. We elucidate this agenda through consideration of three contemporary preoccupations in human geography, comprising emotion, materiality and knowledge

    Topological phase transitions driven by next-nearest-neighbor hopping in two-dimensional lattices

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    For two-dimensional lattices in a tight-binding description, the intrinsic spin-orbit coupling, acting as a complex next-nearest-neighbor hopping, opens gaps that exhibit the quantum spin Hall effect. In this paper, we study the effect of a real next-nearest-neighbor hopping term on the band structure of several Dirac systems. In our model, the spin is conserved, which allows us to analyze the spin Chern numbers. We show that in the Lieb, kagome, and T_3 lattices, variation of the amplitude of the real next-nearest-neighbor hopping term drives interesting topological phase transitions. These transitions may be experimentally realized in optical lattices under shaking, when the ratio between the nearest- and next-nearest-neighbor hopping parameters can be tuned to any possible value. Finally, we show that in the honeycomb lattice, next-nearest-neighbor hopping only drives topological phase transitions in the presence of a magnetic field, leading to the conjecture that these transitions can only occur in multigap systems.Comment: 10 pages, 9 figures [erratum: corrected colors in Fig. 7(a)

    Metabolic control of dendritic cell activation and function: Recent advances and clinical implications

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    Dendritic cells (DCs) are key regulators of both immunity and tolerance by controlling activation and polarization of effector T helper cell and regulatory T cell responses. Therefore, there is a major focus on developing approaches to manipulate DC function for immunotherapy. It is well known that changes in cellular activation are coupled to profound changes in cellular metabolism. Over the past decade there is a growing appreciation that these metabolic changes also underlie the capacity of immune cells to perform particular functions. This has led to the concept that the manipulation of cellular metabolism can be used to shape innate and adaptive immune responses. While most of our understanding in this area has been gained from studies with T cells and macrophages, evidence is emerging that the activation and function of DCs are also dictated by the type of metabolism these cells commit to. We here discuss these new insights and explore whether targeting of metabolic pathways in DCs could hold promise as a novel approach to manipulate the functional properties of DCs for clinical purposes

    Atomic quantum gases in Kagom\'e lattices

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    We demonstrate the possibility of creating and controlling an ideal and \textit{trimerized} optical Kagom\'e lattice, and study the low temperature physics of various atomic gases in such lattices. In the trimerized Kagom\'e lattice, a Bose gas exhibits a Mott transition with fractional filling factors, whereas a spinless interacting Fermi gas at 2/3 filling behaves as a quantum magnet on a triangular lattice. Finally, a Fermi-Fermi mixture at half filling for both components represents a frustrated quantum antiferromagnet with a resonating-valence-bond ground state and quantum spin liquid behavior dominated by continuous spectrum of singlet and triplet excitations. We discuss the method of preparing and observing such quantum spin liquid employing molecular Bose condensates.Comment: 4 pages, 1 figure. Missing affiliations adde

    Use children\u27s books to link the cultures of the world

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    Global education is a timely and important emphasis in schools today. In this article, we consider the goals of global education, present a rationale for providing global education experiences at the age children are most responsive to instruction, explore the ways that children\u27s trade books can provide links among cultures, and consider goals of geography and ways trade books can be used to meet these goals

    Quelles technologies le CIRAD peut-il proposer pour redynamiser la filière cocotier ?

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    Le CIRAD-CP a été amené récemment à préconiser une réorientation des objectifs de la filière cocotier de plusieurs pays producteurs. Cette stratégie repose essentiellement sur une diversification accrue et une plus grande prise en compte des marché locaux, ce qui implique le développement de petites et moyennes unités de transformation sur les lieux de production. La mise en place de telles unités nécessite de pouvoir disposer de technologies pouvant être exploitées efficacement dans de tels contextes et permettant l'obtention de produits de qualité. Dans cette optique, une équipe pluri-disciplinaire du CIRAD a entrepris l'étude de deux procédés relevant des voies humides ou semi-humides : l'extraction après séchage friture, et l'extraction assistée par les enzymes. Les technologies développées sont décrites en détail, et leur adéquation avec les objectifs assignés fait l'objet d'une discussio

    Using storybooks to acquaint children with the continent of Africa

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    I learned so much about Africa. I learned countries, cities, villages, mountains, deserts, rivers, languages. Have you ever been to Africa? I wish I could go. This comment, by a third-grade student, was typical of the responses from students who participated in a project designed to help children learn about Africa by offering them books with African settings. In this article, we share the methods we used to acquaint students with the continent of Africa. We have also included students\u27 responses to a questionnaire, information gathered by an observer, and quotes from students\u27 letters

    Exogenous application of platelet-leukocyte gel during open subacromial decompression contributes to improved patient outcome

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    Background: Platelet-leukocyte gel (PLG) is being used during various surgical procedures in an attempt to enhance the healing process. We studied the effects of PLG on postoperative recovery of patients undergoing open subacromial decompression (OSD). Methods: PLG was produced from platelet-leukocyte-rich plasma (P-LRP), prepared from a unit of whole blood. Forty patients were included in the study. Self-assessed evaluations, using the American Shoulder and Elbow Surgeons scoring system of activities of daily living (ADL), joint instability, pain levels, pain medications, and clinical evaluations for range of motion were conducted. Results: Platelet and leukocyte counts were significantly increased in the P-LRP compared to baseline counts. Treated patients demonstrated decreased visual analog scales for pain and used significantly less pain medication, had an improved range of motion during passive forward elevation, external rotation, external rotation with arm at 90 degrees abduction, internal rotation, and cross body adduction compared to control patients (p < 0.001). No differences in the instability score were observed between the groups. Furthermore, treated patients performed more ADL (p < 0.05). Conclusion: In the PLG-treated group, recovery was faster and patients returned earlier to daily activities and also took less pain medication than control subjects
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