6,266 research outputs found

    Refugee Resettlement and Integration in Germany: Analysis of Media Discourse

    Get PDF
    Refugees are among the most discussed and debated topics worldwide; the massive movement of refugees and asylum seekers facing the world today is the largest since the end of the second world war. The United Nations High Commissioner for Refugees (UNHCR) estimates the total number of refugees in the world to be almost twenty-six million people, while asylum seekers account for around three million. The concept of a refugee is formally defined by the 1951 Convention on the Status of Refugees, which creates a legal status, and states that a refugee is a person who “faces well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group or political opinion”. The issues surrounding refugees are vast and complex, with wide-reaching and long lasting effects. As the world continues to face massive human displacement as a result of fragile states, civil wars, and countless other factors, refugees and related issues will continue to be of vital importance. One key element to the issue of refugees is the question of resettlement and even further the issue of integration

    Construction and Calibration of a Streaked Optical Spectrometer for Shock Temperature

    Full text link
    Here we describe the implementation and calibration of a streaked visible spectrometer (SVS) for optical pyrometry and emission/absorption spectroscopy on light gas gun platforms in the UC Davis Shock Compression Laboratory. The diagnostic consists of an optical streak camera coupled to a spectrometer to provide temporally and spectrally-resolved records of visible emission from dynamically-compressed materials. Fiber optic coupling to the sample enables a small diagnostic footprint on the target face and flexibility of operation on multiple launch systems without the need for open optics. We present the details of calibration (time, wavelength and spectral radiance) for absolute temperature determination and present benchmark measurements of system performance.Comment: 6 pages, 3 figures Davies, E., et al. (accepted). In J. Lane, T. Germann, and M. Armstrong (Eds.), 21st Biennial APS Conference on Shock Compression of Condensed Matter (SCCM19). AIP Publishin

    Instrumental Variables Estimation with Some Invalid Instruments and its Application to Mendelian Randomization

    Full text link
    Instrumental variables have been widely used for estimating the causal effect between exposure and outcome. Conventional estimation methods require complete knowledge about all the instruments' validity; a valid instrument must not have a direct effect on the outcome and not be related to unmeasured confounders. Often, this is impractical as highlighted by Mendelian randomization studies where genetic markers are used as instruments and complete knowledge about instruments' validity is equivalent to complete knowledge about the involved genes' functions. In this paper, we propose a method for estimation of causal effects when this complete knowledge is absent. It is shown that causal effects are identified and can be estimated as long as less than 5050% of instruments are invalid, without knowing which of the instruments are invalid. We also introduce conditions for identification when the 50% threshold is violated. A fast penalized 1\ell_1 estimation method, called sisVIVE, is introduced for estimating the causal effect without knowing which instruments are valid, with theoretical guarantees on its performance. The proposed method is demonstrated on simulated data and a real Mendelian randomization study concerning the effect of body mass index on health-related quality of life index. An R package \emph{sisVIVE} is available online.Comment: 99 pages, 29 figures, 14 table

    Deterministic and Stochastic Prisoner's Dilemma Games: Experiments in Interdependent Security

    Get PDF
    This paper examines experiments on interdependent security prisoner's dilemma games with repeated play. By utilizing a Bayesian hierarchical model, we examine how subjects make investment decisions as a function of their previous experience and their treatment condition. Our main findings are that individuals have differing underlying propensities to invest that vary across time, are affected by both the stochastic nature of the game and even more so by an individual's ability to learn about his or her counterpart's choices. Implications for individual decisions and the likely play of a person's counterpart are discussed in detail.

    Phages and human health: More than idle hitchhikers

    Get PDF
    Bacteriophages, or phages, are viruses that infect bacteria and archaea. Phages have diverse morphologies and can be coded in DNA or RNA and as single or double strands with a large range of genome sizes. With the increasing use of metagenomic sequencing approaches to analyze complex samples, many studies generate massive amounts of “viral dark matter”, or sequences of viral origin unable to be classified either functionally or taxonomically. Metagenomic analysis of phages is still in its infancy, and uncovering novel phages continues to be a challenge. Work over the past two decades has begun to uncover key roles for phages in different environments, including the human gut. Recent studies in humans have identified expanded phage populations in both healthy infants and in inflammatory bowel disease patients, suggesting distinct phage activity during development and in specific disease states. In this review, we examine our current knowledge of phage biology and discuss recent efforts to improve the analysis and discovery of novel phages. We explore the roles phages may play in human health and disease and discuss the future of phage research

    Transient LTRE analysis reveals the demographic and trait-mediated processes that buffer population growth.

    Get PDF
    Temporal variation in environmental conditions affects population growth directly via its impact on vital rates, and indirectly through induced variation in demographic structure and phenotypic trait distributions. We currently know very little about how these processes jointly mediate population responses to their environment. To address this gap, we develop a general transient life table response experiment (LTRE) which partitions the contributions to population growth arising from variation in (1) survival and reproduction, (2) demographic structure, (3) trait values and (4) climatic drivers. We apply the LTRE to a population of yellow-bellied marmots (Marmota flaviventer) to demonstrate the impact of demographic and trait-mediated processes. Our analysis provides a new perspective on demographic buffering, which may be a more subtle phenomena than is currently assumed. The new LTRE framework presents opportunities to improve our understanding of how trait variation influences population dynamics and adaptation in stochastic environments
    corecore