6,975 research outputs found

    Faint Light from Dark Matter: Classifying and Constraining Dark Matter-Photon Effective Operators

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    Even if Dark Matter (DM) is neutral under electromagnetism, it can still interact with the Standard Model (SM) via photon exchange from higher-dimensional operators. Here we classify the general effective operators coupling DM to photons, distinguishing between Dirac/Majorana fermion and complex/real scalar DM. We provide model-independent constraints on these operators from direct and indirect detection. We also constrain various DM-lepton operators, which induce DM-photon interactions via RG running or which typically arise in sensible UV-completions. This provides a simple way to quickly assess constraints on any DM model that interacts mainly via photon exchange or couples to SM leptons.Comment: 32 pages + appendices, 9 + 1 figures, 2 + 1 tables. v2: some clarifications and references added; conclusions unchanged; version published in JHE

    Explaining the Allocation of Bilateral and Multilateral Environmental Aid to Developing Countries

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    In this paper we examine how international development assistance for environmental purposes is allocated to developing countries. In particular, we investigate whether there are patterned differences between environmental aid for international public goods projects versus environmental projects having more localized impacts. We empirically investigate these questions using project project level development assistance data.International Development,

    An introduction to the bootstrap

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    Comparative Life Histories of Georgia and Virginia Cotton Rats

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    Adult hispid cotton rats (Sigmodon hispidus) were collected from the field monthly for \u3e2 years from populations near the northern edge of their range in Virginia and contemporaneously from south-central Georgia. Body measurements and weights were taken at capture, and after dissection embryos, corpora lutea, and placental scars were counted and measured; testes and seminal vesicles were dissected out, measured, and weighed. This allowed comparison of several life-history parameters between the populations and tests of several life-history hypotheses. The breeding season was up to 2 months longer in Georgia than in Virginia, where there was typically a 3-month or longer winter inactive period. Some reproductive activity was observed among Georgia females in all 12 calendar months, whereas pregnancies were never observed in Virginia during November– February. Average litter sizes were significantly higher in Virginia (5.91 ± 6 1.41, up to 13) than in Georgia (5.16 ± 6 1.79, up to 9); this difference may partly result from a higher incidence of embryo resorption and prenatal mortality in the Georgia population, primarily in the cooler 6 months of the year. Virginia rats averaged significantly smaller for both sexes, but this was likely the result of a younger age distribution. Among reproductive males and females, no body-size differences were found between populations except that pregnant females from Virginia averaged significantly longer. Fifty percent and 75% of the random sample of adult females and males, respectively, were reproductively active in Georgia, whereas only 35% and 40% were reproductively active in Virginia. Spermatogenically active males in Virginia had significantly greater relative gonadal mass than their Georgia counterparts. Overwinter survival of parous females was lower in Virginia. Virginia populations, in a more seasonal environment, displayed a more r-selected life history, with greater reproductive allocation, faster growth (except over winter), higher mortality, and less iteroparity

    Job attributes, job satisfaction and the return to health after breast cancer diagnosis and treatment

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    Background: As detection and treatment of cancer has advanced, the number of working age women with breast cancer has increased. This study provides new information on the intersection of breast cancer treatment and job tasks and how, together, they impact employed and newly diagnosed women. Methods: The sample comprised 493 employed women within two months of initiating treatment. Job satisfaction and demands were assessed by pre-diagnosis recall along with measures of mental and physical health and assessed again nine months after initiating treatment. Using seemingly unrelated regression, we tested the effect of job tasks and satisfaction on mental and physical health nine months post-treatment initiation, controlling for pre-diagnosis health status, patient characteristics, and job tasks. Results: Physical job demands prior to diagnosis were not significantly associated with mental or physical health nine months after treatment initiation. Employment in cognitively demanding and less satisfying jobs was associated with decreases in mental health and increases in problems with work or daily activities nine months post-treatment initiation (p\u3c0.05). Women who received five or more cycles of chemotherapy reported lower vitality, social functioning, and worse measures of physical health compared to those who did not receive chemotherapy (p\u3c0.05). Conclusions: Employment in cognitively demanding and unsatisfying jobs may impede mental health recovery, particularly in patients who receive longer chemotherapy regimens. Such information may be used by patients and clinicians in deciding when to undergo chemotherapy and whether job tasks can be restructured to hasten recovery

    Perceptions of five-year competitive categories: Model of how relative age influences competitiveness in Masters sport

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    The purpose of this study was to examine the contrasting perceptions of masters swimmers related to the first and fifth constituent years of a 5-year age category. Swimmers aged between 35 and 93 years (154 male, 184 female) were surveyed at the 2008 FINA World Masters Championships. Exploratory factor analysis indicated the existence of the following five factors considered important for preparation, attendance, and success at masters competitions: awareness of advantages, expectancy, motivation, training, and physiological capacity. One sample ttests showed that masters swimmers are conscious of advantages that 5-year age categories afford to relatively-younger cohorts (i.e., those who are in the first year of any age category). They also perceive that, in the first compared to the fifth year of an age category, they have greater physiological capacity, engage in more training, have higher expectations to perform well, and are more motivated (all ps \u3c.001). Findings point to perceived psycho-social and physical factors that potentially explain why relatively younger masters athletes are more likely to perform better and to participate in masters competitions than relatively older masters athletes

    Debris/ice/TPS assessment and integrated photographic analysis for Shuttle Mission STS-56

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    The Debris Team developed and implemented measures to control damage from debris in the Shuttle operational environment and to make the control measures a part of routine launch flows. These measures include engineering surveillance during vehicle processing and closeout operations, facility and flight hardware inspections before and after launch, and photographic analysis of mission events. Photographic analyses of mission imagery from launch, on-orbit, and landing provide significant data in verifying proper operation of systems and evaluating anomalies. In addition to the Kennedy Space Center (KSC) Photo/Video Analysis, reports from JSC, MSFC, and Rockwell International--Downey are also included in this document to provide an integrated assessment of the mission
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