2,466 research outputs found
Development of quality metrics for ambulatory pediatric cardiology: Chest pain
ObjectiveAs part of the American College of Cardiology Adult Congenital and Pediatric Cardiology Section effort to develop quality metrics (QMs) for ambulatory pediatric practice, the chest pain subcommittee aimed to develop QMs for evaluation of chest pain.DesignA group of 8 pediatric cardiologists formulated candidate QMs in the areas of history, physical examination, and testing. Consensus candidate QMs were submitted to an expert panel for scoring by the RANDâUCLA modified Delphi process. Recommended QMs were then available for open comments from all members.PatientsThese QMs are intended for use in patients 5â18 years old, referred for initial evaluation of chest pain in an ambulatory pediatric cardiology clinic, with no known history of pediatric or congenital heart disease.ResultsA total of 10 candidate QMs were submitted; 2 were rejected by the expert panel, and 5 were removed after the open comment period. The 3 approved QMs included: (1) documentation of family history of cardiomyopathy, early coronary artery disease or sudden death, (2) performance of electrocardiogram in all patients, and (3) performance of an echocardiogram to evaluate coronary arteries in patients with exertional chest pain.ConclusionsDespite practice variation and limited prospective data, 3 QMs were approved, with measurable data points which may be extracted from the medical record. However, further prospective studies are necessary to define practice guidelines and to develop appropriate use criteria in this population.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140026/1/chd12509.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/140026/2/chd12509_am.pd
Role of solvent-anion charge transfer in oxidative degradation of battery electrolytes
Electrochemical stability windows of electrolytes largely determine the limitations of operating regimes of lithium-ion batteries, but the degradation mechanisms are difficult to characterize and poorly understood. Using computational quantum chemistry to investigate the oxidative decomposition that govern voltage stability of multi-component organic electrolytes, we find that electrolyte decomposition is a process involving the solvent and the salt anion and requires explicit treatment of their coupling. We find that the ionization potential of the solvent-anion system is often lower than that of the isolated solvent or the anion. This mutual weakening effect is explained by the formation of the anion-solvent charge-transfer complex, which we study for 16 anion-solvent combinations. This understanding of the oxidation mechanism allows the formulation of a simple predictive model that explains experimentally observed trends in the onset voltages of degradation of electrolytes near the cathode. This model opens opportunities for rapid rational design of stable electrolytes for high-energy batteries
Optical Propagation and Communication
Contains an introduction and reports on four research projects.Maryland Procurement Office Contract MDA 904-90-C5070Maryland Procurement Office Contract MDA 904-93-C4169U.S. Air Force - Office of Scientific Research Grant F49620-93-1-0604Charles S. Draper Laboratories Contract DL-H-441698MIT Lincoln Laboratory Contract CX-16335National Institute of Standards and Technology Grant 60-NANBOD-1052U.S. Army Research Office Grant DAAL03-90-G-0128U.S. Army Research Office Grant DAAH04-93-G-0399U.S. Army Research Office Grant DAAH04-93-G-0187U.S. Air Force - Office of Scientific Research Contract F49620-90-C-003
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CANDELS Observations Of The Structural Properties Of Cluster Galaxies At Z=1.62
We discuss the structural and morphological properties of galaxies in a z = 1.62 proto-cluster using near-IR imaging data from Hubble Space Telescope Wide Field Camera 3 data of the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS). The cluster galaxies exhibit a clear color-morphology relation: galaxies with colors of quiescent stellar populations generally have morphologies consistent with spheroids, and galaxies with colors consistent with ongoing star formation have disk-like and irregular morphologies. The size distribution of the quiescent cluster galaxies shows a deficit of compact (less than or similar to 1 kpc), massive galaxies compared to CANDELS field galaxies at z = 1.6. As a result, the cluster quiescent galaxies have larger average effective sizes compared to field galaxies at fixed mass at greater than 90% significance. Combined with data from the literature, the size evolution of quiescent cluster galaxies is relatively slow from z similar or equal to 1.6 to the present, growing as (1 + z)(-0.6 +/- 0.1). If this result is generalizable, then it implies that physical processes associated with the denser cluster region seem to have caused accelerated size growth in quiescent galaxies prior to z = 1.6 and slower subsequent growth at z < 1.6 compared to galaxies in the lower density field. The quiescent cluster galaxies at z = 1.6 have higher ellipticities compared to lower redshift samples at fixed mass, and their surface-brightness profiles suggest that they contain extended stellar disks. We argue that the cluster galaxies require dissipationless (i.e., gas-poor or "dry") mergers to reorganize the disk material and to match the relations for ellipticity, stellar mass, size, and color of early-type galaxies in z < 1 clusters.NASA NAS5-26555HST GO-12060NASA through from the Space Telescope Science Institute GO-12060European Research CouncilRoyal SocietyTexas AM UniversityGeorge P. and Cynthia Woods Institute for Fundamental Physics and AstronomyAstronom
Structural plasticity of the living kinetochore
The kinetochore is a large, evolutionarily conserved protein structure that connects chromosomes with microtubules. During chromosome segregation, outer kinetochore components track depolymerizing ends of microtubules to facilitate the separation of chromosomes into two cells. In budding yeast, each chromosome has a point centromere upon which a single kinetochore is built, which attaches to a single microtubule. This defined architecture facilitates quantitative examination of kinetochores during the cell cycle. Using three independent measures-calibrated imaging, FRAP, and photoconversion-we find that the Dam1 submodule is unchanged during anaphase, whereas MIND and Ndc80 submodules add copies to form an "anaphase configuration" kinetochore. Microtubule depolymerization and kinesin-related motors contribute to copy addition. Mathematical simulations indicate that the addition of microtubule attachments could facilitate tracking during rapid microtubule depolymerization. We speculate that the minimal kinetochore configuration, which exists from G1 through metaphase, allows for correction of misattachments. Our study provides insight into dynamics and plasticity of the kinetochore structure during chromosome segregation in living cells
Effects of comorbid anxiety disorders on the longitudinal course of pediatric bipolar disorders
OBJECTIVE: To examine the longitudinal effects of comorbid anxiety disorders in youth with bipolar spectrum disorder (BP). METHOD: As part of the Course and Outcome of Bipolar Youth study, 413 youth, who were 7 through 17 years or age and who met criteria for DSM-IV BP-I (n = 244), BP-II (n = 28), and operationally defined bipolar disorder not otherwise specified (BP-NOS) (n = 141) were included. Subjects were followed on average 5 years using the Longitudinal Interval Follow-up Evaluation. Effects of anxiety on the time to mood recovery and recurrence and percentage of time with syndromal and subsyndromal mood symptomatology during the follow-up period were analyzed. RESULTS: At intake and during the follow-up, 62% of youth with BP met criteria for at least 1 anxiety disorder. About 50% of the BP youth with anxiety had â„2 anxiety disorders. Compared to BP youth without anxiety, those with anxiety had significantly more depressive recurrences and significantly longer median time to recovery. The effects of anxiety on recovery disappeared when the severity of depression at intake was taken into account. After adjusting for confounding factors, BP youth with anxiety, particularly those with â„2 anxiety disorders, spent significantly less follow-up time asymptomatic and more time with syndromal mixed/cycling and subsyndromal depressive symptomatology compared to those without anxiety. CONCLUSIONS: Anxiety disorders are common and adversely affect the course of BP in youth, as characterized by more mood recurrences, longer time to recovery, less time euthymic, and more time in mixed/cycling and depressive episodes. Prompt recognition and the development of treatments for BP youth with anxiety are warranted
Optical Propagation and Communication
Contains an introduction and reports on four research project.Maryland Procurement Office Contract MDA 904-90-C-5070Charles S. Draper Laboratories Contract DL-H-441698National Institute of Standards and Technology Grant 60-NANBOD-1052U.S. Army Research Office Grant DAAL03-90-G-0128U.S. Navy - Office of Naval Research Grant N00014-89-J-1163U.S. Air Force - Office of Scientific Research Contract F49620-90-C-003
Attitudes and Performance: An Analysis of Russian Workers
This paper investigates the relationship between locus of control and performance among Russian employees, using survey data collected at 28 workplaces in 2002 in Taganrog and at 47 workplaces in 2003 in Ekaterinburg. We develop a measure that allows us to categorize the Russian employees participating in our survey as exhibiting an internal or external locus of control. We then assess the extent to which there are significant differences between âinternalsâ and âexternalsâ in work-related attitudes that may affect performance. In particular, we focus on (1) attitudes about outcomes associated with hard work, (2) level of job satisfaction, (3) expectation of receiving a desired reward, and (4) loyalty to and involvement with oneâs organization. In each case we identify where gender and generational differences emerge. Our main objective is to determine whether Russian employees who exhibit an internal locus of control perform better than employees with an external locus of control. Our performance measures include earnings, expected promotions, and assessments of the quantity and quality of work in comparison to others at the same organization doing a similar job. Controlling for a variety of worker characteristics, we find that (1) individuals who exhibit an internal locus of control perform better, but this result is not always statistically significant; (2) even among âinternals,â women earn significantly less than men and have a much lower expectation of promotion; (3) even among âinternals,â experience with unemployment has a negative influence on performance.http://deepblue.lib.umich.edu/bitstream/2027.42/40144/3/wp758.pd
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