7,810 research outputs found

    Sharing data from clinical trials: the rationale for a controlled access approach.

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    The move towards increased transparency around clinical trials is welcome. Much focus has been on under-reporting of trials and access to individual patient data to allow independent verification of findings. There are many other good reasons for data sharing from clinical trials. We describe some key issues in data sharing, including the challenges of open access to data. These include issues in consent and disclosure; risks in identification, including self-identification; risks in distorting data to prevent self-identification; and risks in analysis. These risks have led us to develop a controlled access policy, which safeguards the rights of patients entered in our trials, guards the intellectual property rights of the original researchers who designed the trial and collected the data, provides a barrier against unnecessary duplication, and ensures that researchers have the necessary resources and skills to analyse the data

    Self-esteem and self-efficacy in the status attainment process and the multigenerational transmission of advantage

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    Despite considerable evidence of the importance of self-esteem and self-efficacy for agentic, goal-oriented behavior, little attention has been directed to these psychological dimensions in the status attainment literature. The present research uses data from the longitudinal, three-generation Youth Development Study (Nā€Æ=ā€Æ422 three-generation triads) to examine the extent to which adolescent self-esteem and economic self-efficacy affect adult educational and income attainment, and whether these psychological resources are transmitted from one generation to the next, accumulating advantage across generations. We present evidence indicating that both self-esteem and economic self-efficacy are implicated in the attainment process. Adolescent economic self-efficacy had a direct positive effect on adult educational attainment and an indirect effect through educational plans. The influence of self-esteem on adult educational attainment was entirely indirect, through school achievement. We also find evidence that economic self-efficacy was transmitted from parents to children. We conclude that future research should more broadly consider psychological resources in attainment processes from a longitudinal multigenerational perspective

    FREE-SURFACE ADJUSTMENT AND TOPOGRAPHIC WAVES IN COASTAL CURRENTS

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    The adjustment of rotating free-surface flow over a step-like escarpment abutting a vertical wall is discussed in the context of the shallow-water equations. The problem is simplified by considering an escarpment of small fractional depth, so that on the slow topographic timescale the initial, fast PoincarƩ and Kelvin wave adjustment of the free surface is effectively instantaneous, and further simplified by considering the surface displacement to be small compared with the escarpment height so that particle velocities are negligible during the topographic adjustment. Direct solution of the resulting linear system is not straightforward as arbitrarily small-scale motions are generated at sufficiently large times. The problem is reduced by a Green's function technique to one spatial dimension and the wall boundary layers resolved by introducing a scaling based on previously obtained limit solutions. Solutions verify the information-propagation arguments of Johnson (1985) and Gill et al. (1986) and also show interchange of fluid across the escarpment as eddies formed as the current crosses the step travel along the step with shallow water to their right. The pattern of evolution of the system is independent of the direction of the flow, depending solely on the sign of the topographic step. If the escarpment is such that topographic waves travel away from the wall, then a tongue of fluid moves outward along the step: the initial jet along the wall is diverted to flow parallel to, rather than across, the step. If waves travel towards the wall then the current is pinched into the wall and fluid crosses the escarpment in a thinning jet

    Paying the Guard: An Entry-Guard-Based Payment System for Tor

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    When choosing the three relays that compose a circuit, Tor selects the first hop among a restricted number of relays called entry guards, pre-selected by the user himself. The reduced number of entry guards, that until recently was fixed to three, helps in mitigating the effects of several traffic analysis attacks. However, recent literature indicates that the number should be further reduced, and the time during which the user keeps the relays as guards increased. Therefore, developers of Tor recently proposed selecting only one entry guard, which is to be used by the user for all circuits and for a prolonged period of time (nine months). While this design choice was made to increase the security of the protocol, it also opens an unprecedented opportunity for a market mechanism where relays get paid for traffic by the users. In this paper, we propose to use the entry guard as the point-of-sale: users subscribe to their entry guard of choice, and deposit an amount that will be used for paying for the circuits. From the entry guard, income is then distributed to the other relays included in circuits through an inter-relay accounting system. While the user may pay the entry guard using BitCoins, or any other anonymous payment system, the relays exchange I Owe You (IOU) certificates during communication, and settle their balances only at synchronized, later points in time. This novel deferred payment approach overcomes the weaknesses of the previously proposed Tor payment mechanisms: we separate the userā€™s payment from the inter-relay payments, and we effectively unlink both from the chosen path, thus preserving the secrecy of the circuit

    Association between Plasma Antibody Response and Protection in Rainbow Trout Oncorhynchus mykiss Immersion Vaccinated against Yersinia ruckeri

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    A key hallmark of the vertebrate adaptive immune system is the generation of antigen-specific antibodies from B cells. Fish are the most primitive gnathostomes (jawed vertebrates) possessing an adaptive immune system. Vaccination of rainbow trout against enteric redmouth disease (ERM) by immersion in Yersinia ruckeri bacterin confers a high degree of protection to the fish. The immune mechanisms responsible for protection may comprise both cellular and humoral elements but the role of specific immunoglobulins in this system has been questioned and not previously described. The present study demonstrates significant increase in plasma antibody titers following immersion vaccination and significantly reduced mortality during Y. ruckeri challenge

    Why alternative teenagers self-harm: exploring the link between non-suicidal self-injury, attempted suicide and adolescent identity

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    Background: The term ā€˜self-harmā€™ encompasses both attempted suicide and non-suicidal self-injury (NSSI). Specific adolescent subpopulations such as ethnic or sexual minorities, and more controversially, those who identify as ā€˜Alternativeā€™ (Goth, Emo) have been proposed as being more likely to self-harm, while other groups such as ā€˜Jocksā€™ are linked with protective coping behaviours (for example exercise). NSSI has autonomic (it reduces negative emotions) and social (it communicates distress or facilitates group ā€˜bondingā€™) functions. This study explores the links between such aspects of self-harm, primarily NSSI, and youth subculture.<p></p> Methods: An anonymous survey was carried out of 452 15 year old German school students. Measures included: identification with different youth cultures, i.e. Alternative (Goth, Emo, Punk), Nerd (academic) or Jock (athletic); social background, e.g. socioeconomic status; and experience of victimisation. Self-harm (suicide and NSSI) was assessed using Self-harm Behavior Questionnaire and the Functional Assessment of Self-Mutilation (FASM).<p></p> Results: An ā€œAlternativeā€ identity was directly (rā€‰ā‰ˆā€‰0.3) and a ā€œJockā€ identity inversely (rā€‰ā‰ˆā€‰-0.1) correlated with self-harm. ā€œAlternativeā€ teenagers self-injured more frequently (NSSI 45.5% vs. 18.8%), repeatedly self-injured, and were 4ā€“8 times more likely to attempt suicide (even after adjusting for social background) than their non-Alternative peers. They were also more likely to self-injure for autonomic, communicative and social reasons than other adolescents.<p></p> Conclusions: About half of ā€˜Alternativeā€™ adolescentsā€™ self-injure, primarily to regulate emotions and communicate distress. However, a minority self-injure to reinforce their group identity, i.e. ā€˜To feel more a part of a groupā€™
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