5,787 research outputs found

    Low energy ohmmeter can be used to test sensitive circuits, other meters

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    Hazardous circuit ohmmeter is of sufficiently low energy output that it may be used to test extremely sensitive circuits safely, reliably, and accurately. A polyurethane-foam-lined aluminum case provided protection for the unit assembly

    Cryogenic connector for vacuum use Patent

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    Leakproof soft metal seal for use in very high vacuum systems operating at cryogenic temperature

    How pharmacoepidemiology networks can manage distributed analyses to improve replicability and transparency and minimize bias

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    Several pharmacoepidemiology networks have been developed over the past decade that use a distributed approach, implementing the same analysis at multiple data sites, to preserve privacy and minimize data sharing. Distributed networks are efficient, by interrogating data on very large populations. The structure of these networks can also be leveraged to improve replicability, increase transparency, and reduce bias. We describe some features of distributed networks using, as examples, the Canadian Network for Observational Drug Effect Studies, the Sentinel System in the USA, and the European Research Network of Pharmacovigilance and Pharmacoepidemiology. Common protocols, analysis plans, and data models, with policies on amendments and protocol violations, are key features. These tools ensure that studies can be audited and repeated as necessary. Blinding and strict conflict of interest policies reduce the potential for bias in analyses and interpretation. These developments should improve the timeliness and accuracy of information used to support both clinical and regulatory decisions

    Subverting the Spectacle: A Critical Analysis of Culture Jamming as Activist Performance

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    This thesis is a critical analysis of culture jamming as a form of activist performance that focuses on the relationship between performance, politics and ideology in the context of late-capitalism. Culture jamming is defined here as an overtly theatrical approach to political activism that primarily targets corporate power through the appropriation of the signs and symbols that constitute its branding. Drawing on a range of different examples including Reverend Billy and the Stop Shopping Choir, the contemporary subvertising movement, the Yes Men and Liberate Tate, this thesis explores the way in which culture jamming intervenes in the ideological construction of the real by reintroducing a sense of the political into everyday life. Situating my analysis in relation to Guy Debord’s theory of spectacle and the concept of ‘the performative society,’ I draw on a range of theories from performance and theatre studies, philosophy, critical theory and cultural studies to develop the concept of ‘political force.’ Using this idea as my primary reference point I argue that culture jamming is able to meaningfully challenge the pervasive sense of cynicism characteristic of neoliberalism by transforming our experience of everyday life and, in some cases, producing a sense of the world beyond capitalist realism’s horizons of the thinkable

    Mitochondrial metagenomics: letting the genes out of the bottle

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    ‘Mitochondrial metagenomics’ (MMG) is a methodology for shotgun sequencing of total DNA from specimen mixtures and subsequent bioinformatic extraction of mitochondrial sequences. The approach can be applied to phylogenetic analysis of taxonomically selected taxa, as an economical alternative to mitogenome sequencing from individual species, or to environmental samples of mixed specimens, such as from mass trapping of invertebrates. The routine generation of mitochondrial genome sequences has great potential both for systematics and community phylogenetics. Mapping of reads from low-coverage shotgun sequencing of environmental samples also makes it possible to obtain data on spatial and temporal turnover in whole-community phylogenetic and species composition, even in complex ecosystems where species-level taxonomy and biodiversity patterns are poorly known. In addition, read mapping can produce information on species biomass, and potentially allows quantification of within-species genetic variation. The success of MMG relies on the formation of numerous mitochondrial genome contigs, achievable with standard genome assemblers, but various challenges for the efficiency of assembly remain, particularly in the face of variable relative species abundance and intra-specific genetic variation. Nevertheless, several studies have demonstrated the power of mitogenomes from MMG for accurate phylogenetic placement, evolutionary analysis of species traits, biodiversity discovery and the establishment of species distribution patterns; it offers a promising avenue for unifying the ecological and evolutionary understanding of species diversity

    Aspects of the chemistry of some phosphorus halides and pseudohalides

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    The preparation of pseudohalogeno derivatives of the simple phosphorus(V) species PC1(_4)(^+), PC1(_5) and PC1(_6)(^-) has been attempted. In the case of the tetrachlorophosphonium ion only azido-derivatives are observable in normal organic solvents, cyano and thiocyanato derivatives being more stable in liquid halogen media. Isolation of these compounds was not possible. Molecular derivatives based on PC1(_5) seem to be particularly unstable and are only readily observable under forcing conditions for cyanide. The derivatives of the hexachlorophosphate ion are all observable, PX(_6)(^-) being readily formed for X = N(_3), NCS, NCO and OCN although these and the intermediate species are all unstable. The series of cyanides PC1(_6-n)(CN)(_n)(^-) (0 < n < 3) have been isolated as solids and fully characterised, and the presence of isomers for n = 2 and 3 has been clearly established. The six-coordinate fluorochlorophosphates PF(_3)Cl(_3)(^-), PF(_2)C1(_4)(^-) and PFC1(_5)(^-) have been isolated as pure tetraalkylammonium salts and the reactions of these anions studied with respect to substitution by pseudohalides. The observation of PF(_6-n)X(_n)(^-) (X = pseudohalogen) has been carried out by ligand exchange between PF(_6)(^-) and PX(_6)(^-) (where known) or PX(_3) and attempts have been made to isolate compounds, where feasible, by other reactions such as the addition of pseudohalide ions to PF(_5).The use of pairwise interactions has proved invaluable in assigning formulae in the tetrahedral systems, and in both assigning formulae and identifying specific isomers in many of the six-coordinate systems. The substitution patterns in the six-coordinate systems can be rationalised in terms of a simple steric model, or on the basis of ligand field theory for the cyanides. Other six-coordinate systems have been studied with respect to substitution by azide and several new species have been identified

    Are All Successful Communities Alike? Characterizing and Predicting the Success of Online Communities

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    The proliferation of online communities has created exciting opportunities to study the mechanisms that explain group success. While a growing body of research investigates community success through a single measure -- typically, the number of members -- we argue that there are multiple ways of measuring success. Here, we present a systematic study to understand the relations between these success definitions and test how well they can be predicted based on community properties and behaviors from the earliest period of a community's lifetime. We identify four success measures that are desirable for most communities: (i) growth in the number of members; (ii) retention of members; (iii) long term survival of the community; and (iv) volume of activities within the community. Surprisingly, we find that our measures do not exhibit very high correlations, suggesting that they capture different types of success. Additionally, we find that different success measures are predicted by different attributes of online communities, suggesting that success can be achieved through different behaviors. Our work sheds light on the basic understanding of what success represents in online communities and what predicts it. Our results suggest that success is multi-faceted and cannot be measured nor predicted by a single measurement. This insight has practical implications for the creation of new online communities and the design of platforms that facilitate such communities.Comment: To appear at The Web Conference 201

    Effect of breastfeeding on gastrointestinal infection in infants: A targeted maximum likelihood approach for clustered longitudinal data

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    The PROmotion of Breastfeeding Intervention Trial (PROBIT) cluster-randomized a program encouraging breastfeeding to new mothers in hospital centers. The original studies indicated that this intervention successfully increased duration of breastfeeding and lowered rates of gastrointestinal tract infections in newborns. Additional scientific and popular interest lies in determining the causal effect of longer breastfeeding on gastrointestinal infection. In this study, we estimate the expected infection count under various lengths of breastfeeding in order to estimate the effect of breastfeeding duration on infection. Due to the presence of baseline and time-dependent confounding, specialized "causal" estimation methods are required. We demonstrate the double-robust method of Targeted Maximum Likelihood Estimation (TMLE) in the context of this application and review some related methods and the adjustments required to account for clustering. We compare TMLE (implemented both parametrically and using a data-adaptive algorithm) to other causal methods for this example. In addition, we conduct a simulation study to determine (1) the effectiveness of controlling for clustering indicators when cluster-specific confounders are unmeasured and (2) the importance of using data-adaptive TMLE.Comment: Published in at http://dx.doi.org/10.1214/14-AOAS727 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

    A Micro Fluorescent Activated Cell Sorter for Astrobiology Applications

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    A micro-scale Fluorescent Activated Cell Sorter (microFACS) for astrobiology applications is under development. This device is designed to have a footprint of 7 cm x 7 cm x 4 cm and allow live-dead counts and sorting of cells that have fluorescent characteristics from staining. The FACS system takes advantage of microfluidics to create a cell sorter that can fit in the palm of the hand. A micron-scale channel allows cells to pass by a blue diode which causes emission of marker-expressed cells which are detected by a filtered photodetector. A small microcontroller then counts cells and operates high speed valves to select which chamber the cell is collected in (a collection chamber or a waste chamber). Cells with the expressed characteristic will be collected in the collection chamber. This system has been built and is currently being tested. We are also designing a system with integrated MEMS-based pumps and valves for a small and compact unit to fly on small satellite-based biology experiments

    A lifetime of fear of being laughed at: An aged perspective

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    This paper reviews recent literature on gelotophobia (i.e., the fear of being laughed at) with an emphasis on age-specific aspects. Research with two instruments, the GELOPH and PhoPhiKat questionnaires, is presented with special attention being given to sociodemographic correlates and differences in intelligence, character strengths, personality, emotion, and humor. Quite consistently gelotophobes tend to misread positively motivated smiling and laughter (e.g. in social interactions, photographs or auditorily presented) and have lower values in many, but not all, components of humor. They have a low propensity to joy and a disposition to experience shame and fear. More generally they tend to describe themselves as being introverted and neurotic, and they underestimate their own potential while not actually being less capable. Furthermore, new data are presented suggesting that age-related vulnerabilities may be additional sources of ridicule making gelotophobia more of a problem for the elderly. Finally, the prevalence of this fear over the lifespan and potential cohort effects are discussed. It is concluded that more research into this fear and its adverse impact on social interactions, even humorous ones, of the elderly is neede
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