2,149 research outputs found
Coordination of the Co2+and Ni2+Ions in Tf2N-Based Ionic Liquids: A Combined X-ray Absorption and Molecular Dynamics Study
Molecular dynamics (MD) simulations and X-ray absorption spectroscopy (XAS) have been combined to study the coordination of the Co2+ and Ni2+ ions in ionic liquids (ILs) based on the bis(trifluoromethylsulfonyl)imide ([Tf2N]-) anion and having different organic cations, namely, 1-butyl-3-methylimidazolium ([C4mim]+), 1,8-bis(3-methylimidazolium-1-yl)octane ([C8(mim)2]2+), N,N,N-trimethyl-N-(2-hydroxyethyl)ammonium ([choline]+), and butyltrimethylammonium ([BTMA]+). Co and Ni K-edge XAS data have been collected on 0.1 mol L-1 Co(Tf2N)2 and Ni(Tf2N)2 solutions and on the metallic salts. MD simulations have been carried out to obtain structural information on the metal ion coordination. The analysis of the extended X-ray absorption fine structure (EXAFS) spectra of the solutions has been carried out based on the atomistic description provided by MD, and the studied ILs have been found to be able to dissolve both the Co(Tf2N)2 and Ni(Tf2N)2 salts giving rise to a different structural arrangement around the metal ions as compared to the solid state. The combined EXAFS and MD results showed that the Co2+ and Ni2+ ions are surrounded by a first solvation shell formed by six [Tf2N]- anions, each coordinating in a monodentate fashion by means of the oxygen atoms. The nature of the IL organic cation has little or no influence on the overall spatial arrangement of the [Tf2N]- anions, so that stable octahedral complexes of the type [M(Tf2N)6]4- (M = Co, Ni) have been observed in all the investigated ILs
Supply sensitive services in Swiss ambulatory care: An analysis of basic health insurance records for 2003-2007
<p>Abstract</p> <p>Background</p> <p>Swiss ambulatory care is characterized by independent, and primarily practice-based, physicians, receiving fee for service reimbursement. This study analyses supply sensitive services using ambulatory care claims data from mandatory health insurance. A first research question was aimed at the hypothesis that physicians with large patient lists decrease their intensity of services and bill less per patient to health insurance, and vice versa: physicians with smaller patient lists compensate for the lack of patients with additional visits and services. A second research question relates to the fact that several cantons are allowing physicians to directly dispense drugs to patients ('self-dispensation') whereas other cantons restrict such direct sales to emergencies only. This second question was based on the assumption that patterns of rescheduling patients for consultations may differ across channels of dispensing prescription drugs and therefore the hypothesis of different consultation costs in this context was investigated.</p> <p>Methods</p> <p>Complete claims data paid for by mandatory health insurance of all Swiss physicians in own practices were analyzed for the years 2003-2007. Medical specialties were pooled into six main provider types in ambulatory care: primary care, pediatrics, gynecology & obstetrics, psychiatrists, invasive and non-invasive specialists. For each provider type, regression models at the physician level were used to analyze the relationship between the number of patients treated and the total sum of treatment cost reimbursed by mandatory health insurance.</p> <p>Results</p> <p>The results show non-proportional relationships between patient numbers and total sum of treatment cost for all provider types involved implying that treatment costs per patient increase with higher practice size. The related additional costs to the health system are substantial. Regions with self-dispensation had lowest treatment cost for primary care, gynecology, pediatrics and for psychiatrists whereas "prescription only" areas had lowest cost for specialists with non-invasive and invasive activities.</p> <p>Conclusions</p> <p>The results indicate that payment methods for services and for prescription drugs are associated with variations in treatment cost that are unlikely warranted by different medical needs of patients alone. Promoting physician accountability of care by linking reimbursements to quality, not quantity, of services are important policy measures to be considered for health care in Switzerland.</p
Hornet: An Efficient Data Structure for Dynamic Sparse Graphs and Matrices on GPUs
Sparse data computations are ubiquitous in science and engineering. Unlike their dense data counterparts, sparse data computations have less locality and more irregularity in their execution, making them significantly more challenging to parallelize and optimize. Many of the existing formats for sparse data representations on parallel architectures are restricted to static data problems, while those for dynamic data suffer from inefficiency both in terms of performance and memory footprint. This work presents Hornet, a novel data representation that targets dynamic data problems. Hornet is scalable with the input size, and does not require any data re-allocation or re-initialization during the data evolution. We show a Hornet implementation for GPU architectures and compare it to the most widely used static and dynamic data structures
2017-18 Antarctic Travel Project data set
For the 2017-2018 season, we distributed paper surveys to travelers on expedition ships leaving from Ushuaia, Argentina for the Antarctic peninsula. That instrument is included here. We received 362 responses, which is the n throughout the dataset. “Unanswered” indicates that nothing was written on the survey instrument for that question. The Ushuaia Tourism Office, INFUETUR, graciously assisted us in distributing surveys to the expedition guides. Guides then distributed the surveys to their passengers onboard, collected completed surveys, and returned them to the INFUETUR office. These were then mailed to the authors to be analyzed. Once the paper responses were received at Bucknell University, the data was entered into Qualtrics for analysis by Alex Busato. Responses were collected between December 2017 and February 2018, a timeframe that corresponds to the Antarctic tourism season
2018-19 Antarctic Travel Project data set
For the 2018-2019 season, we distributed paper surveys to travelers on expedition ships leaving from Ushuaia, Argentina for the Antarctic peninsula. That instrument is included here. We received 461 responses. The Ushuaia Tourism Office, INFUETUR, graciously assisted us in distributing surveys to the expedition guides. Guides then distributed the surveys to their passengers onboard, collected completed surveys, and returned them to the INFUETUR office. These were then mailed to the authors to be analyzed. We offer our deep thanks to all those who assisted with this survey! Responses were collected between December 2018 and February 2019, a timeframe that corresponds to the Antarctic tourism season
Patient characteristics differently affect early cup and stem loosening in THA: a case-control study on 7,535 patients
We postulated that certain patient characteristics have different effects on early THA component loosening. With two matched case-control studies we assessed 3,028 cups and 5,224 stems. Loosening was defined using signs of mechanical component failure on routine follow-up radiographs or revision for aseptic loosening. Women and men had similar cup-loosening odds, but women had lower odds for stem loosening (p < 0.0001). Odds for cup loosening decreased by 2.1% per additional year of age (p = 0.0004), those for stem loosening by 2.4% (p < 0.0001). Each additional kilogram of weight decreased cup loosening odds by 1.3% (p = 0.0051). Each additional unit of BMI increased stem loosening odds (p = 0.0109). Charnley classes B and C were protective factors against loosening of both components. There were no risk differences for the various main diagnoses. Certain patient characteristics differently affected early cup and stem loosening, although some characteristics had the same protective or harmful effect on component surviva
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