2,735 research outputs found

    The Privatization Challenge in Guyana

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    Size-resolved aerosol and cloud condensation nuclei (CCN) properties in the remote marine South China Sea - Part 1: Observations and source classification

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    Abstract. Ship-based measurements of aerosol and cloud condensation nuclei (CCN) properties are presented for 2 weeks of observations in remote marine regions of the South China Sea/East Sea during the southwestern monsoon (SWM) season. Smoke from extensive biomass burning throughout the Maritime Continent advected into this region during the SWM, where it was mixed with anthropogenic continental pollution and emissions from heavy shipping activities. Eight aerosol types were identified using a k-means cluster analysis with data from a size-resolved CCN characterization system. Interpretation of the clusters was supplemented by additional onboard aerosol and meteorological measurements, satellite, and model products for the region. A typical bimodal marine boundary layer background aerosol population was identified and observed mixing with accumulation mode aerosol from other sources, primarily smoke from fires in Borneo and Sumatra. Hygroscopicity was assessed using the κ parameter and was found to average 0.40 for samples dominated by aged accumulation mode smoke; 0.65 for accumulation mode marine aerosol; 0.60 in an anthropogenic aerosol plume; and 0.22 during a short period that was characterized by elevated levels of volatile organic compounds not associated with biomass burning impacts. As a special subset of the background marine aerosol, clean air masses substantially scrubbed of particles were observed following heavy precipitation or the passage of squall lines, with changes in observed aerosol properties occurring on the order of minutes. Average CN number concentrations, size distributions, and κ values are reported for each population type, along with CCN number concentrations for particles that activated at supersaturations between 0.14 and 0.85 %

    Amorphous metallic alloys: a new advance in thin-film diffusion barriers for copper metallization

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    Copper, which has a lower electrical resistivity and a higher resistance to electromigration than aluminum, is currently being evaluated for ULSI applications as a replacement for aluminum. Drawbacks to the use of copper include its strong tendency to oxidation, a high mobility in metals and semiconductors, and a high reactivity with silicon at temperatures as low as 200°C. To overcome these problems, very effective diffusion barriers need to be developed. These barriers should have a low diffusivity for copper, a high thermal stability, and should lack a driving force for chemical reactions with Cu, silicon or silicides. Unlike aluminum, copper does not form stable intermetallic compounds with the transition metals of the V and Cr groups, and the mutual solid solubilities of these metals with Cu are low, so that these metals would seem th be a logical choice for barrier applications. It has long been known, however, that these arguments are misleading[1]. Previous studies have indeed shown Cu diffuses through grain boundaries and defects in a tantalum layer and inth silicon at a relatively low temperature (450°C) causing a failure of devices[2,3]. The effectiveness of non-reactive and insoluble tantalum barriers can be improved by adding impurities like oxygen or nitrogen th stuff grain boundaries of the material in order th suppress fast grain boundary diffusion[4]. It is difficult, however to reproducibly improve the effectiveness of barriers by adjusting the level of impurities. Since amorphous alloys lack grain boundaries that can act as fast diffusion paths, they should offer an improved alternative for effective barriers [5-71. In this paper we report on the properties and diffusion barrier performance of amorphous tantalum and tungsten silicides and tantalum-silicon-nitrogen ternary alloys [3,81 for Cu metallizations

    Combating stigma in autism research through centering autistic voices: a co-interview guide for qualitative research

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    As autism has gained increased attention in the past few decades, autistic advocates have adopted the phrase “Nothing about us without us,” illustrating the idea that autistic people should be centered in all conversations regarding autism. However, in a large portion of autism research, autistic people are still not meaningfully engaged throughout the research process, leading to continued stigma in research through biased methods. Thus, stigma about autism influences not only the content of autism research, but the ways in which neurotypical people conduct research alongside (or without) autistic people, ultimately resulting in less valid conclusions or research that actively harms the autistic community. One way to address this stigma is through involving autistic individuals as equal partners in the research process, such as by including autistic co-interviewers in qualitative studies of autistic people. In this perspectives piece, we will highlight the benefits of participatory research practices within qualitative research. Furthermore, we will outline methods for conducting co-interviews with autistic research partners and share insights from our experiences implementing this practice. We hope this piece provides researchers the practical resources and inspiration to continue working toward decreasing the stigma surrounding autism in research spaces

    Candida albicans Hypha Formation and Mannan Masking of β-Glucan Inhibit Macrophage Phagosome Maturation

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    Received 28 August 2014 Accepted 28 October 2014 Published 2 December 2014 This is an open-access article distributed under the terms of the Creative Commons Attribution 3.0 Unported license. ACKNOWLEDGMENTS We thank Janet Willment, Aberdeen Fungal Group, University of Aberdeen, for kindly providing the soluble Dectin-1-Fc reporter. All microscopy was performed with the assistance of the University of Aberdeen Core Microscopy & Histology Facility, and we thank the IFCC for their assistance with flow cytometry. We thank the Wellcome Trust for funding (080088, 086827, 075470, 099215, 097377, and 101873). E.R.B. and A.J.P.B. are funded by the European Research Council (ERC-2009-AdG-249793), and J.L. is funded by a Medical Research Council Clinical Training Fellowship.Peer reviewedPublisher PD

    Variation in parent-offspring kinship in socially monogamous systems with extra-pair reproduction and inbreeding

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    ACKNOWLEDGMENTS We thank the Tsawout and Tseycum First Nations bands for allowing access to Mandarte; everyone who contributed to long-term data collection; Lukas Keller and Ryan Germain for helpful discussions; and the European Research Council, UK Royal Society, National Sciences and Engineering Research Council of Canada and Swiss National Science Foundation for their invaluable support. DATA ARCHIVING Data are available from the Dryad Digital Repository: http://dx.doi.org/10.5061/dryad.4r383.Peer reviewedPublisher PD

    Amorphous metallic alloys: a new advance in thin-film diffusion barriers for copper metallization

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    Copper, which has a lower electrical resistivity and a higher resistance to electromigration than aluminum, is currently being evaluated for ULSI applications as a replacement for aluminum. Drawbacks to the use of copper include its strong tendency to oxidation, a high mobility in metals and semiconductors, and a high reactivity with silicon at temperatures as low as 200°C. To overcome these problems, very effective diffusion barriers need to be developed. These barriers should have a low diffusivity for copper, a high thermal stability, and should lack a driving force for chemical reactions with Cu, silicon or silicides. Unlike aluminum, copper does not form stable intermetallic compounds with the transition metals of the V and Cr groups, and the mutual solid solubilities of these metals with Cu are low, so that these metals would seem th be a logical choice for barrier applications. It has long been known, however, that these arguments are misleading[1]. Previous studies have indeed shown Cu diffuses through grain boundaries and defects in a tantalum layer and inth silicon at a relatively low temperature (450°C) causing a failure of devices[2,3]. The effectiveness of non-reactive and insoluble tantalum barriers can be improved by adding impurities like oxygen or nitrogen th stuff grain boundaries of the material in order th suppress fast grain boundary diffusion[4]. It is difficult, however to reproducibly improve the effectiveness of barriers by adjusting the level of impurities. Since amorphous alloys lack grain boundaries that can act as fast diffusion paths, they should offer an improved alternative for effective barriers [5-71. In this paper we report on the properties and diffusion barrier performance of amorphous tantalum and tungsten silicides and tantalum-silicon-nitrogen ternary alloys [3,81 for Cu metallizations

    Cattle remain immunocompetent during the acute phase of foot-and-mouth disease virus infection

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    Infection of cattle with foot-and-mouth disease virus (FMDV) results in the development of long-term protective antibody responses. In contrast, inactivated antigen vaccines fail to induce long-term protective immunity. Differences between susceptible species have also been observed during infection with FMDV, with cattle often developing persistent infections whilst pigs develop more severe symptoms and excrete higher levels of virus. This study examined the early immune response to FMDV in naïve cattle after in-contact challenge. Cattle exposed to FMDV were found to be viraemic and produced neutralising antibody, consistent with previous reports. In contrast to previous studies in pigs these cattle did not develop leucopenia, and the proliferative responses of peripheral blood mononuclear cells to either mitogen or third party antigen were not suppressed. Low levels of type 1 interferon and IL-10 were detected in the circulation. Taken together, these results suggest that there was no generalised immunosuppression during the acute phase of FMDV infection in cattle

    Immune genotypes, immune responses, and survival in a wild bird population

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    ACKNOWLEDGEMENTS We thank the Tsawout and Tseycum bands for allowing us to conduct research on Mandarte Island, and to the many contributors to long-term monitoring, especially L. Keller, P. Nietlisbach, and J. Krippel. We also thank C. Ritland, A. Miscampbell, and G. Huber for their assistance in the laboratory. All work was conducted under permit of the Canadian Wildlife Service and UBC Animal Care Committee. Funding Information: This study was generously supported by the Natural Sciences and Engineering Research Council of Canada via a Post‐doctoral Fellowship award to MJNF (PDF‐2014–454522) and a Discovery Grant to EAMS.Peer reviewedPublisher PD

    Child dietary patterns in Homo sapiens evolution: A systematic review

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    Dietary patterns spanning millennia could inform contemporary public health nutrition. Children are largely absent from evidence describing diets throughout human evolution, despite prevalent malnutrition today signaling a potential genome-environment divergence. This systematic review aimed to identify dietary patterns of children ages 6 months to 10 years consumed before the widespread adoption of agriculture. Metrics of mention frequency (counts of food types reported) and food groups (globally standardized categories) were applied to: compare diets across subsistence modes [gatherer-hunter-fisher (GHF), early agriculture (EA) groups]; examine diet quality and diversity; and characterize differences by life course phase and environmental context defined using Köppen-Geiger climate zones. The review yielded child diet information from 95 cultural groups (52 from GHF; 43 from EA/mixed subsistence groups). Animal foods (terrestrial and aquatic) were the most frequently mentioned food groups in dietary patterns across subsistence modes, though at higher frequencies in GHF than in EA. A broad range of fruits, vegetables, roots and tubers were more common in GHF, while children from EA groups consumed more cereals than GHF, associated with poor health consequences as reported in some studies. Forty-eight studies compared diets across life course phases: 28 showed differences and 20 demonstrated similarities in child versus adult diets. Climate zone was a driver of food patterns provisioned from local ecosystems. Evidence fro
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