127 research outputs found

    Evolution of Electronic Circuits using Carbon Nanotube Composites

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    Evolution-in-materio concerns the computer controlled manipulation of material systems using external stimuli to train or evolve the material to perform a useful function. In this paper we demonstrate the evolution of a disordered composite material, using voltages as the external stimuli, into a form where a simple computational problem can be solved. The material consists of single-walled carbon nanotubes suspended in liquid crystal; the nanotubes act as a conductive network, with the liquid crystal providing a host medium to allow the conductive network to reorganise when voltages are applied. We show that the application of electric fields under computer control results in a significant change in the material morphology, favouring the solution to a classification task

    Accessing elite nurses for research: reflections on the theoretical and practical issues of telephone interviewing

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    Elite groups are interesting as they frequently are powerful (in terms of position, knowledge and influence) and enjoy considerable authority. It is important, therefore, to involve them in research concerned with understanding social contexts and processes. This is particularly pertinent in healthcare, where considerable strategic development and change are features of everyday practice that may be guided or perceived as being guided, by elites. This paper evolved from a study investigating the availability and role of nurses whose remit involved leading nursing research and development within acute NHS Trusts in two health regions in Southern England. The study design included telephone interviews with Directors of Nursing Services during which time the researchers engaged in a reflective analysis of their experiences of conducting research with an `elite' group. Important issues identified were the role of gatekeepers, engagement with elites and the use of the telephone interview method in this context. The paper examines these issues and makes a case for involving executive nurses in further research. The paper also offers strategies to help researchers design and implement telephone interview studies successfully to maximise access to the views and experiences of `hard to reach groups', such as elites, while minimising the associated disruption

    Social environmental impacts on survey cooperation

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    Social environmental influences on survey cooperation are explored using data from six national household surveys in the United States matched to 1990 decennial census data. Consistent with the past literature on prosocial behavior, cooperation rates in these six surveys are found to be lower in urban, densely populated, high crime rate areas. Measures of social cohesion show no evidence of influencing cooperation. The influence of the environmental variables is then observed after introducing statistical controls for household structure, race, age of household members, presence of children, and socioeconomic attributes of households. Over half of the measured influence of the environmental variables is explained by these household-level attributes. These findings have practical import for survey administrators and are informative for the construction of a theory of survey participation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43559/1/11135_2004_Article_BF00153986.pd

    Randomized controlled trial of an intervention to maintain suppression of HIV viremia after prison release: The impact trial

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    Background: HIV-infected individuals transitioning from incarceration to the community are at risk for loss of viral suppression. We compared the effects of imPACT, a multidimensional intervention to promote care engagement after release, to standard care on sustaining viral suppression after community re-entry. Methods: This trial randomized 405 HIV-infected inmates being released from prisons in Texas and North Carolina with HIV-1 RNA levels 0.99). Conclusions: Higher rates of HIV suppression and medical care engagement than expected based on previous literature were observed among HIV-infected patients with suppressed viremia released from prison. Randomization to a comprehensive intervention to motivate and facilitate HIV care access after prison release did not prevent loss of viral suppression. A better understanding of the factors influencing prison releasees' linkage to community care, medication adherence, and maintenance of viral suppression is needed to inform policy and other strategic approaches to HIV prevention and treatment

    Fitting the integrated Spectral Energy Distributions of Galaxies

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    Fitting the spectral energy distributions (SEDs) of galaxies is an almost universally used technique that has matured significantly in the last decade. Model predictions and fitting procedures have improved significantly over this time, attempting to keep up with the vastly increased volume and quality of available data. We review here the field of SED fitting, describing the modelling of ultraviolet to infrared galaxy SEDs, the creation of multiwavelength data sets, and the methods used to fit model SEDs to observed galaxy data sets. We touch upon the achievements and challenges in the major ingredients of SED fitting, with a special emphasis on describing the interplay between the quality of the available data, the quality of the available models, and the best fitting technique to use in order to obtain a realistic measurement as well as realistic uncertainties. We conclude that SED fitting can be used effectively to derive a range of physical properties of galaxies, such as redshift, stellar masses, star formation rates, dust masses, and metallicities, with care taken not to over-interpret the available data. Yet there still exist many issues such as estimating the age of the oldest stars in a galaxy, finer details ofdust properties and dust-star geometry, and the influences of poorly understood, luminous stellar types and phases. The challenge for the coming years will be to improve both the models and the observational data sets to resolve these uncertainties. The present review will be made available on an interactive, moderated web page (sedfitting.org), where the community can access and change the text. The intention is to expand the text and keep it up to date over the coming years.Comment: 54 pages, 26 figures, Accepted for publication in Astrophysics & Space Scienc

    Olfactory Jump Reflex Habituation in Drosophila and Effects of Classical Conditioning Mutations

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    Habituation is a nonassociative learning mechanism, in which an initial response toward repeated stimuli gradually wanes. This is amongst the simplest and most widespread forms of behavioral plasticity. So far, neither the underlying molecular mechanisms nor the precise neural networks of habituation are well understood. We have developed a novel paradigm to quantify habituation of the olfactory jump reflex in Drosophila. We present data demonstrating several behavioral properties of this phenomenon, generally observed in other species. We also show that the dunce and rutabaga memory mutants behave abnormally in this assay, suggesting that this assay might be used in behavioral screens for new mutants with defects in this simpler form of behavioral plasticity

    A Survey of mid and large bodied mammals in Núcleo Caraguatatuba, Serra do Mar State Park, Brazil

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    Nós aplicamos técnicas de amostragem complementares para obter uma lista de espécies de mamíferos de médio e grande porte no Núcleo Caraguatatuba, Parque Estadual da Serra do Mar, Brasil. As amostragens de campo realizaram-se nos meses de Maio e Setembro de 2011. Utilizou-se, censo ao longo de transectos (212,4 km), armadilhas fotográficas (223,2 armadilhas-dias) e armadilhas de pegadas (478 armadilhas-dias). Foram obtidos registros de 18 espécies, pertencentes a 14 famílias e oito ordens. Nós registramos a presença de sete espécies consideradas ameaçadas no Estado de São Paulo, incluindo primatas (Brachyteles arachnoides), Artiodactyla (Mazama americana e Tayassu pecari), Carnivora (Leopardus pardalis, Leopardus tigrinus e Puma concolor) e Perissodactyla (Tapirus terrestris). Com base em numa extrapolação da riqueza de espécies (First order jackknife) nós prevemos que existem entre 19 e 32 espécies de mamíferos de médio e grande porte no Núcleo. Nosso Mammal Priority Index classificou o Núcleo Caraguatatuba como uma área de importância média para a conservação de mamíferos de médio e grande porte na Mata Atlântica. Combinado com o número e a diversidade de espécies registradas, nossos resultados demonstram que este Núcleo é uma área importante para a conservação de mamíferos no Estado.We applied complementary survey techniques to obtain a baseline species list of mid and large bodied mammals in Núcleo Caraguatatuba, Serra do Mar State park, Brazil. Between May and September 2011 we surveyed the community of mid and large bodied mammals using diurnal line transect census (212.4 km), camera-traps (223.2 camera-trap days) and track-stations (478 track-station days). A total of 18 species were recorded from 14 families in eight orders. We recorded the presence of seven species considered threatened in the State of São Paulo, including Primates (Brachyteles arachnoides), Artiodactyla (Mazama cf. americana and Tayassu pecari), Carnivora (Leopardus pardalis, Leopardus tigrinus and Puma concolor) and Perissodactyla (Tapirus terrestris). Based on extrapolated (First order jackknife) species richness estimates we predict that there are between 19 and 32 species of mid and large bodied mammals in the Núcleo. Our revised Mammal Priority Index ranked Núcleo Caraguatatuba as being of medium overall importance for the conservation of mid and large bodied mammals in the Atlantic Forest. Combined with the number and diversity of species recorded, our results demonstrate that this Núcleo is an important area for mammal conservation
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