28,882 research outputs found

    Improving the quality of consent to randomised controlled trials by using continuous consent and clinician training in the consent process

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    Objectives: To assess whether continuous consent, a process whereby information is given to research participants at different stages in a trial, plus clinician training in that process was effective when used by clinicians gaining consent to the TOBY trial. The TOBY trial is a randomised controlled trial investigating the use of whole body cooling for neonates with evidence of perinatal asphyxia. Obtaining valid informed consent for TOBY is difficult; as such, it is a good test of the effectiveness of continuous consent. Methods: Semi-structured interviews were conducted with 30 sets of parents who gave consent to TOBY and with 10 clinicians who sought it using the continuous consent process. Analysis focused on the validity of parental consent based upon the consent components of competence, information, understanding and voluntariness. Results: 19/27 (70%) couples had no significant problems with consent validity at the point of signature. Problems lay mainly with the parents’ competence and understanding. Mothers particularly had competence problems in the early stages of consent. The understanding problems were primarily to do with side effects. Problems in both areas (competence and understanding) reduced markedly, particularly for mothers, in the post signature phase when further discussion took place. Randomisation was generally understood but unpopular. Clinicians did not always give information in stages during the short period of time available before parents gave consent. However, most clinicians were able to give follow up information. Discussion: The consent validity compares favourably with similar trials examined in a comparable study (the Euricon study). Conclusion: Researchers should consider adopting elements of the continuous consent process and clinician training in RCTs, particularly where they have concerns about the quality of consent they are likely to obtain using a conventional process.</p

    Should desperate volunteers be included in randomised controlled trials?

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    Randomised controlled trials (RCTs) sometimes recruit participants who are desperate to receive the experimental treatment. Some claim this practice is unethical for at least three reasons. The first is that the notion of equipoise, which is often used as a justification for running a RCT, is subjective and value-based. Desperate volunteers are clearly not in equipoise and it is their values that should take precedence. The second is that clinicians who enter patients onto trials are disavowing their therapeutic obligation to deliver the best treatment to patients; they are following trial protocols rather than delivering individualised care. Research is not treatment; its ethical justification is different. Consent is crucial. This leads to the third reason: desperate volunteers do not give a proper consent; they are, in effect, coerced. We begin our reply by advocating a notion of equipoise based on, first, expert knowledge and, second, widely shared values. Where such collective, expert equipoise exists there is a prima facie case for a RCT. Next we argue that trial entry does not involve clinicians’ disavowing their therapeutic obligation; individualised care based on whims and fancies is not in patients’ best interest. Finally, we argue that where equipoise exists it is acceptable to limit access to experimental agents. In the cases desperate volunteers are not coerced because their desperation does not translate into a right to receive what they desire. </p

    Evaluating complementary medicine: methodological challenges of randomised controlled trials

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    Complementary medicine has a different philosophy from conventional medicine, presenting challenges to research methodology. Rigorous evaluation of complementary medicine could provide much needed evidence of its effectiveness. Good design of randomised controlled trials will avoid invalid results and misrepresentation of the holistic essence of complementary medicine. Practitioners need to be recognised as a component in or contributor to complementary treatment. Both specific and non-specific outcome measures with long follow up are needed to adequately encompass the essence of complementary medicine

    Uniqueness of Petrov type D spatially inhomogeneous irrotational silent models

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    The consistency of the constraint with the evolution equations for spatially inhomogeneous and irrotational silent (SIIS) models of Petrov type I, demands that the former are preserved along the timelike congruence represented by the velocity of the dust fluid, leading to \emph{new} non-trivial constraints. This fact has been used to conjecture that the resulting models correspond to the spatially homogeneous (SH) models of Bianchi type I, at least for the case where the cosmological constant vanish. By exploiting the full set of the constraint equations as expressed in the 1+3 covariant formalism and using elements from the theory of the spacelike congruences, we provide a direct and simple proof of this conjecture for vacuum and dust fluid models, which shows that the Szekeres family of solutions represents the most general class of SIIS models. The suggested procedure also shows that, the uniqueness of the SIIS of the Petrov type D is not, in general, affected by the presence of a non-zero pressure fluid. Therefore, in order to allow a broader class of Petrov type I solutions apart from the SH models of Bianchi type I, one should consider more general ``silent'' configurations by relaxing the vanishing of the vorticity and the magnetic part of the Weyl tensor but maintaining their ``silence'' properties i.e. the vanishing of the curls of Eab,HabE_{ab},H_{ab} and the pressure pp.Comment: Latex, 19 pages, no figures;(v2) some clarification remarks and an appendix are added; (v3) minor changes to match published versio

    Collapsible reflector Patent

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    Self erecting parabolic reflector design for use in spac

    The measurement errors in the Swift-UVOT and XMM-OM

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    The probability of photon measurement in some photon counting instrumentation, such as the Optical Monitor on the XMM-Newton satellite, and the UVOT on the Swift satellite, does not follow a Poisson distribution due to the detector characteristics, but a Binomial distribution. For a single-pixel approximation, an expression was derived for the incident countrate as a function of the measured count rate by Fordham, Moorhead and Galbraith (2000). We show that the measured countrate error is binomial, and extend their formalism to derive the error in the incident count rate. The error on the incident count rate at large count rates is larger than the Poisson-error of the incident count rate.Comment: 4 pages, 2 postscript figures, submitted to MNRA
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