974 resultados para Schatten-p class
Resumo:
This article explores the idea of 'cultural mobility' both as a way of thinking about the polarizing logic of class relations and practices in contemporary society and as a means by which the debate over the cultural omnivore might be advanced. The concept of cultural mobility refers to the differential capacity to engage with or consume cultural goods and services across the entire spectrum of cultural life, an ability which is itself premised upon an unequal, class-related distribution in cultural competence. Cultural mobility, then, is the ability to move at will between cultural realms, a freedom to choose where one is positioned in the cultural landscape. I argue that the concept provides fertile ground for exploring possible interconnections between a number of divergent strands in current social theory which have largely developed independently of each other. At the same time much of this theoretical effort remains divorced from concrete research agendas. Using data collected as part of a major study of Australian cultural consumption, the article provides a case study of cultural mobility and its class moorings which serves to clarify some of the existing confusions concerning the cultural omnivore.
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The initiation of graft vs. host disease (GVHD) after stem cell transplantation is dependent on direct antigen presentation by host antigen presenting cells (APC) while the effect of indirect antigen presentation by donor APC is unknown. We have studied the role of indirect antigen presentation in allogenic responses by adding populations of cytokine-expanded donor APC to haematopoietic grafts that would otherwise induce lethal GVHD. Progenipoietin-1 (a synthetic G-CSF/Flt-3 L molecule) and G-CSF expanded myeloid DC, plasmacytoid DC and a novel granulocyte-monocyte precursor population (GM) that differentiate into class IIpos, CD80/CD86pos, CD40neg APC during GVHD. Whereas addition of plasmacytoid and myeloid donor DC augmented GVHD, GM cells induced transplant tolerance via MHC class II restricted generation of IL-10-secreting regulatory T cells. Thus a population of cytokine expanded granulocyte-monocyte precursors function as regulatory antigen presenting cells, suggesting that G-CSF derivatives may have application in disorders characterised by a loss of self-tolerance.
Resumo:
Spermatozoa of most crustacean species are nonmotile and are packed into spermatophores. In Decapoda, spermatophores are highly variable in morphology and can be useful in the solving of taxonomic and systematic questions, especially among the Anomura. In this study, the morphology and morphometry of the spermatophores of the western Atlantic hermit crabs Pagurus brevidactylus and P criniticornis are described. The abdomen of fresh male specimens was dissected to expose the reproductive system and to extract the spermatophores, which were analyzed by stereoscopic, light, and scanning electron microscopy. The vas deferens can be divided macroscopically in three regions, all of them containing spermatophores. Tripartite spermatophores are composed of an elongated cylindrical main ampulla, a triangular accessory ampulla, a narrow cylindrical peduncle, and a round pedestal. Dimensions of the spermatophore components are positively correlated to the size of the crab. Morphological patterns observed in this study resemble those of other pagurid hermit crabs investigated to date. The morphological character distribution confirms classifications based on adult morphology and molecular analysis. J. Morphol. 272:1271-1280, 2011. (C) 2011 Wiley-Liss, Inc.
Resumo:
This paper is devoted to the study of the class of continuous and bounded functions f : [0, infinity] -> X for which exists omega > 0 such that lim(t ->infinity) (f (t + omega) - f (t)) = 0 (in the sequel called S-asymptotically omega-periodic functions). We discuss qualitative properties and establish some relationships between this type of functions and the class of asymptotically omega-periodic functions. We also study the existence of S-asymptotically omega-periodic mild solutions of the first-order abstract Cauchy problem in Banach spaces. (C) 2008 Elsevier Inc. All rights reserved.
Resumo:
We study the existence of asymptotically almost periodic classical solutions for a class of abstract neutral integro-differential equation with unbounded delay. A concrete application to partial neutral integro-differential equations which arise in the study of heat conduction in fading memory material is considered. (C) 2011 Elsevier Inc. All rights reserved.
Resumo:
Antigen recognition by cytotoxic CD8 T cells is dependent upon a number of critical steps in MHC class I antigen processing including proteosomal cleavage, TAP transport into the endoplasmic reticulum, and MHC class 1 binding. Based on extensive experimental data relating to each of these steps there is now the capacity to model individual antigen processing steps with a high degree of accuracy. This paper demonstrates the potential to bring together models of individual antigen processing steps, for example proteosome cleavage, TAP transport, and MHC binding, to build highly informative models of functional pathways. In particular, we demonstrate how an artificial neural network model of TAP transport was used to mine a HLA-binding database so as to identify H LA-binding peptides transported by TAP. This integrated model of antigen processing provided the unique insight that HLA class I alleles apparently constitute two separate classes: those that are TAP-efficient for peptide loading (HLA-B27, -A3, and -A24) and those that are TAP-inefficient (HLA-A2, -B7, and -B8). Hence, using this integrated model we were able to generate novel hypotheses regarding antigen processing, and these hypotheses are now capable of being tested experimentally. This model confirms the feasibility of constructing a virtual immune system, whereby each additional step in antigen processing is incorporated into a single modular model. Accurate models of antigen processing have implications for the study of basic immunology as well as for the design of peptide-based vaccines and other immunotherapies. (C) 2004 Elsevier Inc. All rights reserved.
Resumo:
Reactions of the model acylium ion (CH3)(2)N-C+=O with acyclic, exocyclic, and Spiro acetals of the general formula (RO)-O-1-(CRR4)-R-3-OR2-upole mass spectrometry. Characteristic intrinsic reactivities were observed for each of these classes of acetals. The two most Characteristic intrinsic reactivities were observed for each of these classes of acetals. The two most common reactions observed were hydride and alkoxy anion [(RO-)-O-1 and (RO-)-O-2] abstraction. Other specific reactions were also observed: (a) a secondary polar [4(+) + 2] cycloaddition for acetals bearing alpha,beta-unsaturated R-3 or R-4 substituents and (b) OH- abstraction for exocyclic and spiro acetals. These structurally diagnostic reactions, in conjunction with others observed previously for cyclic acetals, are shown to reveal the class of the acetal molecule and its ring type and substituents and to permit their recognition and distinction from other classes of isomeric molecules.
Resumo:
Layered Double Hydroxides are a class of materials that can be described as positively charged layers of divalent and trivalent cations in the centre of edge-sharing octahedra. Cholesterol derivatives such as cholic acid are substances that play an important role in the digestion of fat components by the organism. This work presents a study on the intercalation of cholate anions in calcined MgAl-CO(3)-HDL. Isotherm experiments were performed at three different temperatures to evaluate the capacity of anion removal by sorption in the calcined LDH. The plateau was reached in all conditions. Increasing temperature results in decreasing cholate sorption. Characteristic peaks of LDH regenerated with OH(-) anions were observed at lower cholate concentrations. A peak in 2 theta equals to 7.5 degrees and peaks between 15 degrees and 20 degrees are observed. Those peaks are the same as the ones observed in the pure sodium cholate PXRD. At higher cholate concentrations the sorbed solids present PXRD related to an additional layered phase, which is related to intercalation of cholate anions with basal spacing equal to 34.3 angstrom. Thus, the cholate anions are also intercalated with a bilayer molecular arrangement at equilibrium concentrations at the isotherms plateau. (C) 2009 Elsevier Ltd. All rights reserved.
Resumo:
Teen Triple P is a multilevel system of intervention that is designed to provide parents with specific strategies to promote the positive development of their teenage children as they make the transition into high school and through puberty. The program is based on a combination of education about the developmental needs of adolescents, skills training to improve communication and problem-solving, plus specific modules to deal with common problems encountered by parents and adolescents that can escalate into major conflict and violence. It is designed to increase the engagement of parents of adolescent and pre-adolescent children by providing them with easy access to evidencebased parenting advice and support. This paper presents data collected as part of a survey of over 1400 students in first year high school at 9 Brisbane schools. The survey instrument was constructed to obtain students' reports about behaviour which is known to be associated with their health and wellbeing, and also on the extent to which their parents promoted or discouraged such behaviour at home, at school, and in their social and recreational activities in the wider community. Selected data from the survey were extracted and presented to parents at a series of parenting seminars held at the schools to promote appropriate parenting of teenagers. The objectives were to provide parents with accurate data about teenagers' behaviour, and about teenagers' reports of how they perceived their parents' behaviour. Normative data on parent and teenager behaviour will be presented from the survey as well as psychometric data relating to the reliability and validity of this new measure. Implications of this strategy for increasing parent engagement in parenting programs that aim to reduce behavioural and emotional problems in adolescents will be discussed.
Resumo:
This note is motivated from some recent papers treating the problem of the existence of a solution for abstract differential equations with fractional derivatives. We show that the existence results in [Agarwal et al. (2009) [1], Belmekki and Benchohra (2010) [2], Darwish et al. (2009) [3], Hu et al. (2009) [4], Mophou and N`Guerekata (2009) [6,7], Mophou (2010) [8,9], Muslim (2009) [10], Pandey et al. (2009) [11], Rashid and El-Qaderi (2009) [12] and Tai and Wang (2009) [13]] are incorrect since the considered variation of constant formulas is not appropriate. In this note, we also consider a different approach to treat a general class of abstract fractional differential equations. (C) 2010 Elsevier Ltd. All rights reserved.
Resumo:
In this paper we discuss the existence of solutions for a class of abstract degenerate neutral functional differential equations. Some applications to partial differential equations are considered.