601,698 research outputs found
Extended quasi-additivity of Tsallis entropies
We consider statistically independent non-identical subsystems with different
entropic indices q1 and q2. A relation between q1, q2 and q' (for the entire
system) extends a power law for entropic index as a function of distance r. A
few examples illustrate a role of the proposed constraint q' < min(q1, q2) for
the Beck's concept of quasi-additivity.Comment: to appear in Physica
Accessibility of the lowest quintet state of organic molecules through triplet-triplet annihilation; an INDO CI study
By the spin-allowed annihilation of two metastable triplet states (triplet-triplet annihilation-TTA) one electronic ground state (S0) and one electronically excited singlet (Si) or triplet (Ti) or quintet (Qk) state are created, provided the sum of the excitation energies of the two metastable triplet states is sufficient for the creation of the particular excited state. On the basis of semi-empirical calcns. of the excitation energies of T1 and Q1 of forty-six conjugated org. compds. it is shown that Q1 of benzene and some other compds. should be accessible through annihilation of like triplets (homo-TTA), and that Q1 of many compds. should be accessible through annihilation of unlike triplets (hetero-TTA). The population of Q1, competing with that of S1, should cause an unusual magnetic-field dependence of the delayed fluorescence S1 -> S0. In favorable cases, the population of Q1 should lead to an inverse (pos.) magnetic high-field effect on the delayed fluorescence
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Public Performance Metrics: Driving Physician Motivation and Performance
Introduction: As providers transition from âfee-for-serviceâ to âpay-for-performanceâ models, focus has shifted to improving performance. This trend extends to the emergency department (ED) where visits continue to increase across the United States. Our objective was to determine whether displaying public performance metrics of physician triage data could drive intangible motivators and improve triage performance in the ED.Methods: This is a single institution, time-series performance study on a physician-in-triage system. Individual physician baseline metricsânumber of patients triaged and dispositioned per shiftâwere obtained and prominently displayed with identifiable labels during each quarterly physician group meeting. Physicians were informed that metrics would be collected and displayed quarterly and that there would be no bonuses, punishments, or required training; physicians were essentially free to do as they wished. It was made explicit that the goal was to increase the number triaged, and while the number dispositioned would also be displayed, it would not be a focus, thereby acting as this studyâs control. At the end of one year, we analyzed metrics.Results: The groupâs average number of patients triaged per shift were as follows: Q1-29.2; Q2-31.9; Q3-34.4; Q4-36.5 (Q1 vs Q4, p < 0.00001). The average numbers of patients dispositioned per shift were Q1-16.4; Q2-17.8; Q3-16.9; Q4-15.3 (Q1 vs Q4, p = 0.14). The top 25% of Q1 performers increased their average numbers triaged from Q1-36.5 to Q4-40.3 (ie, a statistically insignificant increase of 3.8 patients per shift [p = 0.07]). The bottom 25% of Q1 performers, on the other hand, increased their averages from Q1-22.4 to Q4-34.5 (ie, a statistically significant increase of 12.2 patients per shift [p = 0.0013]).Conclusion: Public performance metrics can drive intangible motivators (eg, purpose, mastery, and peer pressure), which can be an effective, low-cost strategy to improve individual performance, achieve institutional goals, and thrive in the pay-for-performance era
Differential Relationship between Physical Activity and Intake of Added Sugar and Nutrient-Dense Foods: A Cross-Sectional Analysis
A curvilinear relationship exists between physical activity (PA) and dietary energy intake (EI), which is reduced in moderately active when compared to inactive and highly active individuals, but the impact of PA on eating patterns remains poorly understood. Our goal was to establish the relationship between PA and intake of foods with varying energy and nutrient density. Data from the 2009â2010 United States National Health and Nutrition Examination Survey were used to include a Dietary Screener Questionnaire for estimated intakes of added sugar, fruits and vegetables, whole grains, fiber, and dairy. Participants (n = 4766; 49.7% women) were divided into sex-specific quintiles based on their habitual PA. After adjustment for age, body mass index, household income, and education, intakes were compared between PA quartiles, using the lowest activity quintile (Q1) as reference. Women in the second to fourth quintile (Q2-Q4) consumed less added sugar from sugary foods (+2 tsp/day) and from sweetened beverages (+2 tsp/day; all p \u3c 0.05 vs. Q1). In men, added sugar intake was elevated in the highest activity quintile (Q5: +3 ± 1 tsp/day, p = 0.007 vs. Q1). Fruit and vegetable intake increased (women: Q1-Q4 +0.3 ± 0.1 cup eq/day; p \u3c 0.001; men: Q1-Q3 +0.3 ± 0.1 cup eq/day, p = 0.002) and stagnated in higher quintiles. Dairy intake increased with PA only in men (Q5: +0.3 ± 0.1 cup eq/day, p \u3c 0.001 vs. Q1). Results demonstrate a differential relationship between habitual PA and dietary intakes, whereby moderate but not necessarily highest PA levels are associated with reduced added sugar and increased nutrient-dense food consumption. Future research should examine specific mechanisms of food choices at various PA levels to ensure dietary behaviors (i.e., increased sugary food intake) do not negate positive effects of PA
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Individual IKs channels at the surface of mammalian cells contain two KCNE1 accessory subunits.
KCNE1 (E1) ÎČ-subunits assemble with KCNQ1 (Q1) voltage-gated K(+) channel α-subunits to form IKslow (IKs) channels in the heart and ear. The number of E1 subunits in IKs channels has been an issue of ongoing debate. Here, we use single-molecule spectroscopy to demonstrate that surface IKs channels with human subunits contain two E1 and four Q1 subunits. This stoichiometry does not vary. Thus, IKs channels in cells with elevated levels of E1 carry no more than two E1 subunits. Cells with low levels of E1 produce IKs channels with two E1 subunits and Q1 channels with no E1 subunits--channels with one E1 do not appear to form or are restricted from surface expression. The plethora of models of cardiac function, transgenic animals, and drug screens based on variable E1 stoichiometry do not reflect physiology
Characterizing the Existence of Optimal Proof Systems and Complete Sets for Promise Classes.
In this paper we investigate the following two questions: Q1: Do there exist optimal proof systems for a given language L? Q2: Do there exist complete problems for a given promise class C? For concrete languages L (such as TAUT or SAT) and concrete promise classes C (such as NPâ©coNP, UP, BPP, disjoint NP-pairs etc.), these ques-tions have been intensively studied during the last years, and a number of characterizations have been obtained. Here we provide new character-izations for Q1 and Q2 that apply to almost all promise classes C and languages L, thus creating a unifying framework for the study of these practically relevant questions. While questions Q1 and Q2 are left open by our results, we show that they receive affirmative answers when a small amount on advice is avail-able in the underlying machine model. This continues a recent line of research on proof systems with advice started by Cook and KrajÌıcÌek [6]
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