492 research outputs found

    Harnessing ICTs : a Canadian First Nations experience; introduction to K-Net

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    Spanish version available in IDRC Digital Library: Cómo aprovechar las TICs : una experiencia de las Primeras Naciones Canadienses; introducción a K-NetThis document is an introduction to the work of K-Net, a program of Keewaytinook Okimakanak (KO) tribal council. K-Net is providing information and communication technologies (ICTs) to First Nations communities in remote regions of northwestern. Ontario, Canada. In less than a decade, KO communities have experienced a major technological transformation, and this case study series outlines some of the key lessons learned from their experience

    Bayesian evidence as a tool for comparing datasets

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    We introduce a new conservative test for quantifying the consistency of two or more datasets. The test is based on the Bayesian answer to the question, ``How much more probable is it that all my data were generated from the same model system than if each dataset were generated from an independent set of model parameters?''. We make explicit the connection between evidence ratios and the differences in peak chi-squared values, the latter of which are more widely used and more cheaply calculated. Calculating evidence ratios for three cosmological datasets (recent CMB data (WMAP, ACBAR, CBI, VSA), SDSS and the most recent SNe Type 1A data) we find that concordance is favoured and the tightening of constraints on cosmological parameters is indeed justified.Comment: 4 pages, accepted by Phys. Rev.

    Co‐foundress confinement elicits kinship effects in a naturally sub‐social parasitoid

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    Kinship among interacting individuals is often associated with sociality and also with sex ratio effects. Parasitoids in the bethylid genus Goniozus are sub-social, with single foundress females exhibiting post-ovipositional maternal care via short-term aggressive host and brood defence against conspecific females. Due to local mate competition (LMC) and broods normally being produced by a single foundress, sex ratios are female biased. Contests between adult females are, however, not normally fatal and aggression is reduced when competing females are kin, raising the possibility of multi-foundress reproduction on some hosts. Here we screen for further life-history effects of kinship by varying the numbers and relatedness of foundresses confined together with a host resource and also by varying the size of host. We confined groups of 1 to 8 Goniozus nephantidis females together with a host for 5+ days. Multi-foundress groups were either all siblings or all non-siblings. Our chief expectations included that that competition for resources would be more intense among larger foundress groups but diminished by both larger host size and closer foundress relatedness, affecting both foundress mortality and reproductive output. From classical LMC theory, we expected that offspring group sex ratios would be less female biased when there were more foundresses and from extended LMC theory we expected that sex ratios would be more female biased when foundresses were close kin. We found that confinement led to the death of some females (11% overall) but only when host resources were most limiting. Mortality of foundresses was less common when foundresses were siblings. Developmental mortality among offspring was considerably higher in multi-foundress clutches but was unaffected by foundress relatedness. Groups of sibling foundresses collectively produced similar numbers of offspring to non-sibling groups. There was little advantage for individual females to reproduce in multi-foundress groups: single foundresses suppressed even the largest hosts presented and had the highest per capita production of adult offspring. Despite single-foundress reproduction being the norm, G. nephantidis females in multi-foundress groups appear to attune sex allocation according to both foundress number and foundress relatedness: broods produced by sibling foundresses had sex ratios similar to broods produced by single foundresses (ca. 11% males) whereas the sex ratios of broods produced by non-sibling females were approximately 20% higher and broadly increased with foundress number. We conclude that relatedness and host size may combine to reduce selection against communal reproduction on hosts and that, unlike other studied parasitoids, G. nephantidis sex ratios conform to predictions of both classical and extended LMC theor

    A semiparametric Bayesian proportional hazards model for interval censored data with frailty effects

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    <p>Abstract</p> <p>Background</p> <p>Multivariate analysis of interval censored event data based on classical likelihood methods is notoriously cumbersome. Likelihood inference for models which additionally include random effects are not available at all. Developed algorithms bear problems for practical users like: matrix inversion, slow convergence, no assessment of statistical uncertainty.</p> <p>Methods</p> <p>MCMC procedures combined with imputation are used to implement hierarchical models for interval censored data within a Bayesian framework.</p> <p>Results</p> <p>Two examples from clinical practice demonstrate the handling of clustered interval censored event times as well as multilayer random effects for inter-institutional quality assessment. The software developed is called survBayes and is freely available at CRAN.</p> <p>Conclusion</p> <p>The proposed software supports the solution of complex analyses in many fields of clinical epidemiology as well as health services research.</p

    Sailing into the wind : new disciplines in Australian higher education

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    Much is made of the potential of lifelong learning for individuals and organisations. In this article we tend to make much less of it, certainly with respect to its use in universities to discipline academics. Nevertheless, we argue that academics now need to re-learn the positions they occupy and the stances they take in response to the marketisation of Australian universities. In particular, we suggest that the position of (pure) critique no longer commands attention in Australian contexts of higher education, although the paper does not suggest a disregard for a critical stance purely for the sake of participation. It is in understanding the interconnections between position and stance , and how they might be strategically performed during the everyday practices of academics, that a more promising way of engaging with the venalities of the market is envisaged; a strategy that could be described as \u27sailing into the wind\u27. In discussing these matters, the paper draws on semi-structured interviews with academics located in university faculties/departments/schools of education along Australia\u27s eastern seaboard

    Computational Models of Timing Mechanisms in the Cerebellar Granular Layer

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    A long-standing question in neuroscience is how the brain controls movement that requires precisely timed muscle activations. Studies using Pavlovian delay eyeblink conditioning provide good insight into this question. In delay eyeblink conditioning, which is believed to involve the cerebellum, a subject learns an interstimulus interval (ISI) between the onsets of a conditioned stimulus (CS) such as a tone and an unconditioned stimulus such as an airpuff to the eye. After a conditioning phase, the subject’s eyes automatically close or blink when the ISI time has passed after CS onset. This timing information is thought to be represented in some way in the cerebellum. Several computational models of the cerebellum have been proposed to explain the mechanisms of time representation, and they commonly point to the granular layer network. This article will review these computational models and discuss the possible computational power of the cerebellum

    The roles of the formal and informal sectors in the provision of effective science education

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    For many years, formal school science education has been criticised by students, teachers, parents and employers throughout the world. This article presents an argument that a greater collaboration between the formal and the informal sector could address some of these criticisms. The causes for concern about formal science education are summarised and the major approaches being taken to address them are outlined. The contributions that the informal sector currently makes to science education are identified. It is suggested that the provision of an effective science education entails an enhanced complementarity between the two sectors. Finally, there is a brief discussion of the collaboration and communication still needed if this is to be effective
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