166 research outputs found

    Transmission Properties of the oscillating delta-function potential

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    We derive an exact expression for the transmission amplitude of a particle moving through a harmonically driven delta-function potential by using the method of continued-fractions within the framework of Floquet theory. We prove that the transmission through this potential as a function of the incident energy presents at most two real zeros, that its poles occur at energies nω+εn\hbar\omega+\varepsilon^* (0<Re(ε)<ω0<Re(\varepsilon^*)<\hbar\omega), and that the poles and zeros in the transmission amplitude come in pairs with the distance between the zeros and the poles (and their residue) decreasing with increasing energy of the incident particle. We also show the existence of non-resonant "bands" in the transmission amplitude as a function of the strength of the potential and the driving frequency.Comment: 21 pages, 12 figures, 1 tabl

    The association of dietary choline and betaine with the risk of type 2 diabetes: The atherosclerosis risk in communities (aric) study

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    OBJECTIVE To examine the association between dietary intake of choline and betaine and the risk of type 2 diabetes. RESEARCH DESIGN AND METHODS Among 13,440 Atherosclerosis Risk in Communities (ARIC) study participants, the prospective longitudinal association between dietary choline and betaine intake and the risk of type 2 diabetes was assessed using interval-censored Cox pro-portional hazards and logistic regression models adjusted for baseline potential confounding variables. RESULTS Among 13,440 participants (55% women, mean age 54 [SD 7.4] years), 1,396 developed incident type 2 diabetes during median follow-up of 9 years from 1987 to 1998. There was no statistically significant association between every 1-SD increase in dietary choline and risk of type 2 diabetes (hazard ratio [HR] 1.01 [95% CI 0.87, 1.16]) nor between dietary betaine intake and the risk of type 2 diabetes (HR 1.01 [0.94, 1.10]). Those in the highest quartile of dietary choline intake did not have a statistically significant higher risk of type 2 diabetes than those in the lowest choline quartile (HR 1.09 [0.84, 1.42]); similarly, dietary betaine intake was not associated with the risk of type 2 diabetes comparing the highest quartile to the lowest (HR 1.06 [0.87, 1.29]). Among women, there was a higher risk of type 2 diabetes, comparing the highest to lowest dietary choline quartile (HR 1.54 [1.06, 2.25]), while in men, the association was null (HR 0.82 [0.57, 1.17]). Nevertheless, there was a nonsignificant interaction between high choline intake and sex on the risk of type 2 diabetes (P 5 0.07). The results from logistic regression were similar. CONCLUSIONS Overall and among male participants, dietary choline or betaine intakes were not associated with the risk of type 2 diabetes. Among female participants, there was a trend for a modestly higher risk of type 2 diabetes among those with the highest as compared with the lowest quartile of dietary choline intake. Our study should inform clinical trials on dietary choline and betaine supplementation in relationship with the risk of type 2 diabetes

    Physical activity trajectories and subsequent fall risk: ARIC Study

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    To examine the impact of moderate to vigorous intensity physical activity (MVPA) trajectories during midlife and older adulthood with subsequent fall risk in later life. Cross-temporal analyses were conducted in 15,792 participants (27% black, 55% women) aged 45 to 64 years enrolled in the Atherosclerosis Risk in Communities (ARIC) Study. MVPA was collected at Exams 1 (1987–89), 3 (1993–95) and 5 (2011–13) using the ARIC/Baecke questionnaire. Latent class growth analysis was used to identify the MVPA trajectory groups. Reported falls outcomes were collected in 2013–14, 2015–16, and 2016–17. Generalized Linear Models were used to estimate associations of baseline predictors with trajectory class membership, as well as associations of trajectory classes with any falling (adjusted incident relative risks, aIRR) and with number of falls (adjusted relative rates, aRR). Four primary trajectory classes emerged, reflecting longitudinal patterns of maintained high (48%), maintained low (22%), increasing (14%) and decreasing (15%) MVPA. After adjustment for covariates, the decreasing MVPA trajectory group had a 14% higher risk of reporting any falling compared to the maintained high MVPA group [aIRR = 1.14 (1.01, 1.28)]. When compared to the maintained high MVPA group, the maintained low and decreasing group had a 28% [aRR = 1.28 (1.14, 1.44)] and 27% [aRR = 1.27 (1.17, 1.38)] higher rate in the reported number of falls, respectively. Findings support public health campaigns targeting habitual MVPA or exercise for fall prevention and suggest that interventions should be initiated in midlife; a time when individuals may be more able and willing to change behavior

    Novel Bound States Treatment of the Two Dimensional Schrodinger Equation with Pseudocentral Plus Multiparameter Noncentral Potential

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    By converting the rectangular basis potential V(x,y) into the form as V(r)+V(r, phi) described by the pseudo central plus noncentral potential, particular solutions of the two dimensional Schrodinger equation in plane-polar coordinates have been carried out through the analytic approaching technique of the Nikiforov and Uvarov (NUT). Both the exact bound state energy spectra and the corresponding bound state wavefunctions of the complete system are determined explicitly and in closed forms. Our presented results are identical to those of the previous works and they may also be useful for investigation and analysis of structural characteristics in a variety of quantum systemsComment: Published, 16 page

    Prognostic Variation Among Very High-Risk and High-Risk Individuals With Atherosclerotic Cardiovascular Disease

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    Given the availability of an effective but expensive lipid-lowering medication, proprotein convertase subtilisin/kexin type 9 inhibitors, the American Heart Association and the American College of Cardiology 2018 cholesterol guideline introduced a new classification of “very high-risk” (i.e., multiple major atherosclerotic cardiovascular diseases [ASCVDs] or a major ASCVD þ multiple high-risk conditions) versus “high-risk” for patients with prior ASCVD. A few recent studies reported risk variation within very high-risk ASCVD, with multiple ASCVDs conferring higher risk than 1 ASCVD þ $2 high-risk conditions. However, these studies did not evaluate whether the constellation of high-risk conditions in 1 ASCVD may equate to the risk of multiple ASCVDs or whether the new classification has implications for heart failure

    Albuminuria and Prognosis Among Individuals With Atherosclerotic Cardiovascular Disease: The ARIC Study

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    The American College of Cardiology and the American Heart Association 2018 Cholesterol Guideline proposed the new classification of “very high-risk” atherosclerotic cardiovascular disease (ASCVD) (multiple ASCVDs or 1 ASCVD plus $2 high-risk conditions) to guide intensive secondary prevention. This guideline takes into account reduced glomerular filtration rate (GFR) as a high-risk condition, but not albuminuria, a measure of kidney damage, that is more strongly associated with cardiovascular outcomes than reduced GFR. Importantly, the assessment of albuminuria is already recommended in patients with diabetes and hypertension, and thus, data of albuminuria are readily available in many patients with ASCVD. We explored whether urine albumin-to-creatinine ratio (ACR) is independently associated with adverse outcomes and can improve risk prediction in persons with ASCVD beyond the high-risk conditions in the guideline

    MultiCellDS : a community-developed standard for curating microenvironment-dependent multicellular data

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    Exchanging and understanding scientific data and their context represents a significant barrier to advancing research, especially with respect to information siloing. Maintaining information provenance and providing data curation and quality control help overcome common concerns and barriers to the effective sharing of scientific data. To address these problems in and the unique challenges of multicellular systems, we assembled a panel composed of investigators from several disciplines to create the MultiCellular Data Standard (MultiCellDS) with a use-case driven development process. The standard includes (1) digital cell lines, which are analogous to traditional biological cell lines, to record metadata, cellular microenvironment, and cellular phenotype variables of a biological cell line, (2) digital snapshots to consistently record simulation, experimental, and clinical data for multicellular systems, and (3) collections that can logically group digital cell lines and snapshots. We have created a MultiCellular DataBase (MultiCellDB) to store digital snapshots and the 200+ digital cell lines we have generated. MultiCellDS, by having a fixed standard, enables discoverability, extensibility, maintainability, searchability, and sustainability of data, creating biological applicability and clinical utility that permits us to identify upcoming challenges to uplift biology and strategies and therapies for improving human health

    The status of GEO 600

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    The GEO 600 laser interferometer with 600m armlength is part of a worldwide network of gravitational wave detectors. GEO 600 is unique in having advanced multiple pendulum suspensions with a monolithic last stage and in employing a signal recycled optical design. This paper describes the recent commissioning of the interferometer and its operation in signal recycled mode

    MultiCellDS: a community-developed standard for curating microenvironment-dependent multicellular data

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    Exchanging and understanding scientific data and their context represents a significant barrier to advancing research, especially with respect to information siloing. Maintaining information provenance and providing data curation and quality control help overcome common concerns and barriers to the effective sharing of scientific data. To address these problems in and the unique challenges of multicellular systems, we assembled a panel composed of investigators from several disciplines to create the MultiCellular Data Standard (MultiCellDS) with a use-case driven development process. The standard includes (1) digital cell lines, which are analogous to traditional biological cell lines, to record metadata, cellular microenvironment, and cellular phenotype variables of a biological cell line, (2) digital snapshots to consistently record simulation, experimental, and clinical data for multicellular systems, and (3) collections that can logically group digital cell lines and snapshots. We have created a MultiCellular DataBase (MultiCellDB) to store digital snapshots and the 200+ digital cell lines we have generated. MultiCellDS, by having a fixed standard, enables discoverability, extensibility, maintainability, searchability, and sustainability of data, creating biological applicability and clinical utility that permits us to identify upcoming challenges to uplift biology and strategies and therapies for improving human health
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