3,339 research outputs found

    CPT Violation, Strings, and Neutral-Meson Systems

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    This talk provides a short overview of recent results on possible CPT violation and some associated experimental signatures.Comment: Presented at Orbis Scientiae, January 199

    On directed information theory and Granger causality graphs

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    Directed information theory deals with communication channels with feedback. When applied to networks, a natural extension based on causal conditioning is needed. We show here that measures built from directed information theory in networks can be used to assess Granger causality graphs of stochastic processes. We show that directed information theory includes measures such as the transfer entropy, and that it is the adequate information theoretic framework needed for neuroscience applications, such as connectivity inference problems.Comment: accepted for publications, Journal of Computational Neuroscienc

    R-parity violating resonant stop production at the Large Hadron Collider

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    We have investigated the resonant production of a stop at the Large Hadron Collider, driven by baryon number violating interactions in supersymmetry. We work in the framework of minimal supergravity models with the lightest neutralino being the lightest supersymmetric particle which decays within the detector. We look at various dilepton and trilepton final states, with or without b-tags. A detailed background simulation is performed, and all possible decay modes of the lighter stop are taken into account. We find that higher stop masses are sometimes easier to probe, through the decay of the stop into the third or fourth neutralino and their subsequent cascades. We also comment on the detectability of such signals during the 7 TeV run, where, as expected, only relatively light stops can be probed. Our conclusion is that the resonant process may be probed, at both 10 and 14 TeV, with the R-parity violating coupling {\lambda}"_{312} as low as 0.05, for a stop mass of about 1 TeV. The possibility of distinguishing between resonant stop production and pair-production is also discussed.Comment: 20 pages, 4 figures, 6 tables; Version accepted by JHE

    The Economic Impact of Early Life Environmental Tobacco Smoke Exposure: Early Intervention for Developmental Delay

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    BACKGROUND AND OBJECTIVES: Early-life exposure to environmental tobacco smoke (ETS) can result in developmental delay as well as childhood asthma and increased risk of cancer. The high cost of childhood asthma related to ETS exposure has been widely recognized; however, the economic impact of ETS-related developmental delay has been less well understood. METHODS AND RESULTS:The Columbia Center for Children\u27s Environmental Health (CCCEH) has reported adverse effects of prenatal ETS exposure on child development in a cohort of minority women and children in New York City (odds ratio of developmental delay = 2.36; 95% confidence interval 1.22-4.58). Using the environmentally attributable fraction (EAF) approach, we estimated the annual cost of one aspect of ETS-related developmental delay: Early Intervention Services. The estimated cost of these services per year due to ETS exposure is \u3e Dollars 50 million per year for New York City Medicaid births and Dollars 99 million per year for all New York City births. CONCLUSION:The high annual cost of just one aspect of developmental delay due to prenatal exposure to ETS provides further impetus for increased prevention efforts such as educational programs to promote smoke-free homes, additional cigarette taxes, and subsidizing of smoking cessation programs

    The Effect of Ambient Air Pollution during Early Pregnancy on Fetal Ultrasonic Measurements during Mid-Pregnancy

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    BACKGROUND: Over the past decade there has been mounting evidence that ambient air pollution during pregnancy influences fetal growth. OBJECTIVES: This study was designed to examine possible associations between fetal ultrasonic measurements collected from 15,623 scans (13–26 weeks gestation) and ambient air pollution during early pregnancy. METHODS: We calculated mothers ’ average monthly exposures over the first 4 months of pregnancy for the following pollutants: particulate matter < 10 µm aerodynamic diameter (PM10), ozone, nitrogen dioxide, and sulfur dioxide. We examined associations with fetal femur length (FL), biparietal diameter (BPD), head circumference (HC), and abdominal circumference (AC). Final analyses included scans from only those women within 2 km of an air pollution monitoring site. We controlled for long-term trend, season, temperature, gestation, mother’s age, socioeconomic status, and fetal sex. RESULTS: A reduction in fetal AC was associated with O3 during days 31–60 [–1.42 mm; 95 % confidence interval (CI), –2.74 to –0.09], SO2 during days 61–90 (–1.67 mm; 95 % CI, –2.94 to –0.40), and PM10 during days 91–120 (–0.78 mm; 95 % CI, –1.49 to –0.08). Other results showed a reduction in BPD (–0.68 mm; 95 % CI, –1.09 to –0.27) associated with SO2 during days 0–30, a reduction in HC (–1.02 mm; 95 % CI, –1.78 to –0.26) associated with PM10 during days 91–120, and a reduction in FL associated with PM10 during days 0–30 (–0.28 mm; 95 % CI, –0.48 to –0.08) and 91–120 (–0.23; 95 % CI, –0.42 to –0.04). CONCLUSION: We found strong effects of ambient air pollution on ultrasound measures. Future research, including more individually detailed data, is needed to confirm our results. KEY WORDS: air pollution, fetal growth, pregnancy, temperature, ultrasound. Environ Health Perspect 116:362–369 (2008). doi:10.1289/ehp.10720 available vi

    Supersymmetric Monojets at the Large Hadron Collider

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    Supersymmetric monojets may be produced at the Large Hadron Collider by the process qg -> squark neutralino_1 -> q neutralino_1 neutralino_1, leading to a jet recoiling against missing transverse momentum. We discuss the feasibility and utility of the supersymmetric monojet signal. In particular, we examine the possible precision with which one can ascertain the neutralino_1-squark-quark coupling via the rate for monojet events. Such a coupling contains information on the composition of the neutralino_1 and helps bound dark matter direct detection cross-sections and the dark matter relic density of the neutralino_1. It also provides a check of the supersymmetric relation between gauge couplings and gaugino-quark-squark couplings.Comment: 46 pages, 10 figures. The appendix has been rewritten to correct an error that appears in all previous versions of the appendix. This error has no effect on the results in the main body of the pape

    Multimorbidity in bipolar disorder and under-treatment of cardiovascular disease: a cross sectional study

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    Background: Individuals with serious mental disorders experience poor physical health, especially increased rates of cardiometabolic morbidity and premature morbidity. Recent evidence suggests that individuals with schizophrenia have numerous comorbid physical conditions which may be under-recorded and under-treated but to date very few studies have explored this issue for bipolar disorder. Methods:We conducted a cross-sectional analysis of a dataset of 1,751,841 registered patients within 314 primary-care practices in Scotland, U.K. Bipolar disorder was identified using Read Codes recorded within electronic medical records. Data on 32 common chronic physical conditions were also assessed. Potential prescribing inequalities were evaluated by analyzing prescribing data for coronary heart disease (CHD) and hypertension. Results: Compared to controls, individuals with bipolar disorder were significantly less likely to have no recorded physical conditions (OR 0.59, 95% CI 0.54-0.63) and significantly more likely to have one physical condition (OR 1.27, 95% CI 1.16-1.39), two physical conditions (OR 1.45, 95% CI 1.30-1.62) and three or more physical conditions (OR 1.44, 95% CI 1.30-1.64). People with bipolar disorder also had higher rates of thyroid disorders, chronic kidney disease, chronic pain, chronic obstructive airways disease and diabetes but, surprisingly, lower recorded rates of hypertension and atrial fibrillation. People with bipolar disorder and comorbid CHD or hypertension were significantly more likely to be prescribed no antihypertensive or cholesterol-lowering medications compared to controls, and bipolar individuals with CHD or hypertension were significantly less likely to be on 2 or more antihypertensive agents. Conclusions: Individuals with bipolar disorder are similar to individuals with schizophrenia in having a wide range of comorbid and multiple physical health conditions. They are also less likely than controls to have a primary-care record of cardiovascular conditions such as hypertension and atrial fibrillation. Those with a recorded diagnosis of CHD or hypertension were less likely to be treated with cardiovascular medications and were treated less intensively. This study highlights the high physical healthcare needs of people with bipolar disorder, and provides evidence for a systematic under-recognition and under-treatment of cardiovascular disease in this group

    Analytic Results for Higgs Production in Bottom Fusion

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    We evaluate analytically the cross section for Higgs production plus one jet through bottom quark fusion. By considering the small pT limit we derive expressions for the resummation coefficients governing the structure of large logarithms, and compare these expressions with those available in the literature.Comment: 14 pages, 7 figure
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