534 research outputs found
Contact, Political Solidarity and Collective Action: An Indian Case Study of Relations between Historically Disadvantaged Communities
Research on the contact hypothesis has highlighted the role of contact in improving intergroup relations. Most of this research has addressed the problem of transforming the prejudices of historically advantaged communities, thereby eroding wider patterns of discrimination and inequality. In the present research, drawing on evidence from a cross-sectional survey conducted in New Delhi, we explored an alternative process through which contact may promote social change, namely by fostering political solidarity and empowerment amongst the disadvantaged. The results indicated that Muslim studentsˈ experiences of contact with other disadvantaged communities were associated with their willingness to participate in joint collective action to reduce shared inequalities. This relationship was mediated by perceptions of collective efficacy and shared historical grievances and moderated by positive experiences of contact with the Hindu majority. Implications for recent debates about the relationship between contact and social change are discussed
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Semi-direct allorecognition
Adaptive CD8 T-cell immunity is the principal arm of the cellular alloimmune response, but its development requires help. This can be provided by CD4 T cells that recognize alloantigen "indirectly," as self-restricted allopeptide, but this process remains unexplained, because the target epitopes for CD4 and CD8 T-cell recognition are "unlinked" on different cells (recipient and donor antigen presenting cells (APCs), respectively). Here, we test the hypothesis that the presentation of intact and processed MHC class I alloantigen by recipient dendritic cells (DCs) (the "semidirect" pathway) allows linked help to be delivered by indirect-pathway CD4 T cells for generating destructive cytotoxic CD8 T-cell alloresponses. We show that CD8 T-cell-mediated rejection of murine heart allografts that lack hematopoietic APCs requires host secondary lymphoid tissue (SLT). SLT is necessary because within it, recipient dendritic cells can acquire MHC from graft parenchymal cells and simultaneously present it as intact protein to alloreactive CD8 T cells and as processed peptide alloantigen for recognition by indirect-pathway CD4 T cells. This enables delivery of essential help for generating cytotoxic CD8 T-cell responses that cause rapid allograft rejection. In demonstrating the functional relevance of the semidirect pathway to transplant rejection, our findings provide a solution to a long-standing conundrum as to why SLT is required for CD8 T-cell allorecognition of graft parenchymal cells and suggest a mechanism by which indirect-pathway CD4 T cells provide help for generating effector cytotoxic CD8 T-cell alloresponses at late time points after transplantation.This work was supported by a British Heart Foundation project grant, the National Institute of Health Research Cambridge Biomedical Research Centre and the National Institute of Health Research Blood and Transplant Research Unit. SH was supported by an Academy of Medical Sciences / Wellcome Trust starter grant and the European Society for Organ Transplantation Junior Basic Science Research Grant. JA and IH were supported by Wellcome Trust Clinical Research Training Fellowships and Raymond and Beverly Sackler Scholarships.This is the author accepted manuscript. The final version is available from PNAS via http://dx.doi.org/10.1073/pnas.151353311
Surgical trial in traumatic intracerebral haemorrhage (STITCH) : A randomised controlled trial of early surgery compared with Initial conservative treatment
Funding This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme.Peer reviewedPublisher PD
POE-Δ: Towards an engineering framework for solving change problems
Many organizational problems are addressed through change to existing Information Systems (IT) rather than radical new design. In the face of high incidence of IT project failure, devising effective ways to tackle this type of change remains an open challenge.The paper discusses the motivation, theoretical foundation, characteristics and evaluation of a novel framework, referred to as POE-Δ, which is rooted in design and engineering and is aimed at providing systematic support for representing, structuring and exploring change problems. We generalize an existing theory of greenfield design as problem solving for application to change problems: from a theoretical perspective POE-Δ is a subset of its parent framework, allowing the seamless integration of greenfield and brownfield design to tackle change problems. Its initial case study evaluation shows that POE-Δ allows the systematic analysis of change problems, leading to clearer understanding and better informed decision making
Immigration Opposition Among U.S. Whites: General Ethnocentrism or Media Priming of Attitudes About Latinos?
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97221/1/pops928.pd
Alzheimer’s disease genetic risk and cognitive reserve in relationship to long-term cognitive trajectories among cognitively normal individuals
Background:
Both Alzheimer’s disease (AD) genetic risk factors and indices of cognitive reserve (CR) influence risk of cognitive decline, but it remains unclear whether they interact. This study examined whether a CR index score modifies the relationship between AD genetic risk factors and long-term cognitive trajectories in a large sample of individuals with normal cognition.
Methods:
Analyses used data from the Preclinical AD Consortium, including harmonized data from 5 longitudinal cohort studies. Participants were cognitively normal at baseline (M baseline age = 64 years, 59% female) and underwent 10 years of follow-up, on average. AD genetic risk was measured by (i) apolipoprotein-E (APOE) genetic status (APOE-ε2 and APOE-ε4 vs. APOE-ε3; N = 1819) and (ii) AD polygenic risk scores (AD-PRS; N = 1175). A CR index was calculated by combining years of education and literacy scores. Longitudinal cognitive performance was measured by harmonized factor scores for global cognition, episodic memory, and executive function.
Results:
In mixed-effects models, higher CR index scores were associated with better baseline cognitive performance for all cognitive outcomes. APOE-ε4 genotype and AD-PRS that included the APOE region (AD-PRSAPOE) were associated with declines in all cognitive domains, whereas AD-PRS that excluded the APOE region (AD-PRSw/oAPOE) was associated with declines in executive function and global cognition, but not memory. There were significant 3-way CR index score × APOE-ε4 × time interactions for the global (p = 0.04, effect size = 0.16) and memory scores (p = 0.01, effect size = 0.22), indicating the negative effect of APOE-ε4 genotype on global and episodic memory score change was attenuated among individuals with higher CR index scores. In contrast, levels of CR did not attenuate APOE-ε4-related declines in executive function or declines associated with higher AD-PRS. APOE-ε2 genotype was unrelated to cognition.
Conclusions:
These results suggest that APOE-ε4 and non-APOE-ε4 AD polygenic risk are independently associated with global cognitive and executive function declines among individuals with normal cognition at baseline, but only APOE-ε4 is associated with declines in episodic memory. Importantly, higher levels of CR may mitigate APOE-ε4-related declines in some cognitive domains. Future research is needed to address study limitations, including generalizability due to cohort demographic characteristics
Using rival effects to identify synergies and improve merger typologies
"The strategic management literature has found it difficult to differentiate between collusive and efficiency-based synergies in horizontal merger activity. We propose a schematic to classify mergers that yields more information on merger types and merger effects, and that can, moreover, distinguish between mergers characterized largely by collusion-based synergies and mergers characterized largely by efficiency-based synergies. Crucial to the proposed measurement procedure is that it encompasses the impact of merger events not only on merging firms - as is custom - but also on non-merging competitor firms (the rivals). Employing the event-study methodology with stock-market data on samples of large horizontal mergers drawn from the US and UK (an Anglo-Saxon sub-sample) and from the European continent, we demonstrate how the proposed schematic can better clarify the nature of merger activity." (author's abstract)"Die Literatur über strategisches Management hatte bisher Schwierigkeiten, zwischen wettbewerbsschädlichen und Effizienz steigenden Synergien bei horizontalen Zusammenschlüssen zu differenzieren. Wir schlagen einen konzeptionellen Rahmen vor, um Fusionen zu klassifizieren, welcher mehr Informationen sowohl über die Fusionstypologie als auch über die Wirkung von Zusammenschlüssen entschlüsselt und welcher eine klare Abgrenzung zwischen wettbewerbsschädlichen und wettbewerbsfreundlichen Fusionen erlaubt. Fundamental für diesen konzeptionellen Rahmen ist, dass er nicht nur die Wirkung der Fusion auf die fusionierenden Unternehmen (was typisch in der Literatur ist) umfasst, sondern auch ihre Wirkung auf die Rentabilität der Wettbewerber. Wir wenden eine Ereignisstudienmethode mit Aktiendaten an, um unsere Kategorisierung empirisch umzusetzen. Im Vergleich einer Stichprobe von Fusionen in der angelsächsischen Welt (US und Großbritannien) mit Fusionen zwischen kontinentaleuropäischen Firmen zeigen wir, wie unsere Methodologie hilfreich sein kann, die Art der Fusionsaktivitäten zu identifizieren." (Autorenreferat
Organizational structure as a determinant of performance: Evidence from mutual funds
This article develops and tests a model of how organizational structure influences organizational performance. Organizational structure, conceptualized as the decision‐making structure among a group of individuals, is shown to affect the number of initiatives pursued by organizations and the omission and commission errors (Type I and II errors, respectively) made by organizations. The empirical setting is more than 150,000 stock‐picking decisions made by 609 mutual funds. Mutual funds offer an ideal and rare setting to test the theory, since there are detailed records on the projects they face, the decisions they make, and the outcomes of these decisions. The study's independent variable, organizational structure, is coded based on fund management descriptions made by Morningstar, and estimates of the omission and commission errors are computed by a novel technique that uses bootstrapping to create measures that are comparable across funds. The findings suggest that organizational structure has relevant and predictable effects on a wide range of organizations. In particular, the article shows empirically that increasing the consensus threshold required by a committee in charge of selecting projects leads to more omission errors, fewer commission errors, and fewer approved projects. Applications include designing organizations that achieve a given mix of exploration and exploitation, as well as predicting the consequences of centralization and decentralization. This work constitutes the first large‐sample empirical test of the model by Sah and Stiglitz ( 1986 ). Copyright © 2012 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91096/1/1969_ftp.pd
Augmentation of Recipient Adaptive Alloimmunity by Donor Passenger Lymphocytes within the Transplant.
Chronic rejection of solid organ allografts remains the major cause of transplant failure. Donor-derived tissue-resident lymphocytes are transferred to the recipient during transplantation, but their impact on alloimmunity is unknown. Using mouse cardiac transplant models, we show that graft-versus-host recognition by passenger donor CD4 T cells markedly augments recipient cellular and humoral alloimmunity, resulting in more severe allograft vasculopathy and early graft failure. This augmentation is enhanced when donors were pre-sensitized to the recipient, is dependent upon avoidance of host NK cell recognition, and is partly due to provision of cognate help for allo-specific B cells from donor CD4 T cells recognizing B cell MHC class II in a peptide-degenerate manner. Passenger donor lymphocytes may therefore influence recipient alloimmune responses and represent a therapeutic target in solid organ transplantation.This work was supported by a British Heart Foundation project grant, the National Institute of Health Research Cambridge Biomedical Research Centre and the National Institute of Health Research Blood and Transplant Research Unit. IGH and JMA were supported by a Wellcome Trust Clinical Research Training Fellowship and Raymond and Beverly Sackler Scholarship. KSP was supported by an Academy of Medical Sciences / Wellcome Trust starter grant.This is the final version of the article. It first appeared from Elsevier via https://doi.org/10.1016/j.celrep.2016.04.00
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Strategy tools-in-use: A framework for understanding “technologies of rationality” in practice
In response to critiques of strategy tools as unhelpful or potentially dangerous for organizations, we suggest casting a sociological eye on how tools are actually mobilized by strategy makers. In conceptualizing strategy tools as tools-in-use, we offer a framework for examining the ways that the affordances of strategy tools and the agency of strategy makers interact to shape how and when tools are selected and applied. Further, rather than evaluating the ‘correct’ or ‘incorrect’ use of tools, we highlight the variety of outcomes that result, not just for organizations but also for the tools and the individuals who use them. We illustrate this framework with a vignette and propose an agenda and methodological approaches for further scholarship on the use of strategy tools
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