5,410 research outputs found
Comment: Struggles with Survey Weighting and Regression Modeling
Comment: Struggles with Survey Weighting and Regression Modeling
[arXiv:0710.5005]Comment: Published in at http://dx.doi.org/10.1214/088342307000000177 the
Statistical Science (http://www.imstat.org/sts/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Oxidative Metabolism in Perfused Surviving Dog Skin11From the Department of Medicine, Section of Dermatology, University of Chicago, Chicago, Ill. This work was supported in part by the Research and Development Division, Office of the Surgeon General, Department of the Army, Contract number DA-49-007-MD-411.
Silicon Nanocrystal Field-Effect Light-Emitting Devices
We describe the operation of a light-emitting device in which silicon nanocrystals are electrically pumped via the field-effect electroluminescence (EL) mechanism. In contrast to the simultaneous bipolar carrier injection used in conventional p-n junction light-emitting diodes, this device employs sequential unipolar programming of both electrons and holes across a tunneling barrier from the same semiconductor channel. Light emission is strongly correlated with the injection of second carriers into nanocrystals that have been previously programmed with charges of the opposite sign. The properties of this device are well described by the model of a charge injection through Coulomb field modified tunneling processes. We additionally consider limiting performance bounds for potential future devices fabricated from nanocrystals with different radiative emission rates
On the Perturbations of Viscous Rotating Newtonian Fluids
The perturbations of weakly-viscous, barotropic, non-self-gravitating,
Newtonian rotating fluids are analyzed via a single partial differential
equation. The results are then used to find an expression for the
viscosity-induced normal-mode complex eigenfrequency shift, with respect to the
case of adiabatic perturbations. However, the effects of viscosity are assumed
to have been incorporated in the unperturbed (equilibrium) model. This paper is
an extension of the normal-mode formalism developed by Ipser & Lindblom for
adiabatic pulsations of purely-rotating perfect fluids. The formulas derived
are readily applicable to the perturbations of thin and thick accretion disks.
We provide explicit expressions for thin disks, employing results from previous
relativistic analyses of adiabatic normal modes of oscillation. In this case,
we find that viscosity causes the fundamental p- and g- modes to grow while the
fundamental c-mode could have either sign of the damping rate.Comment: Accepted for publication by The Astrophysical Journal. 11 pages, no
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Using Business Students \u27 Precepts To Predict Ethical Decision Making
A 13-item questionnaire was administered to 259 business students on two college campuses, with a combined population of 1,872, to determine if religious affiliation, upbringing, profession, college major and several other independent variables (labeled precepts) could be used to predict students\u27 perceptions of some main problems of philosophy. Stepwise multiple regression models revealed several significant differences, with p\u3c.05 in four separate models. Precepts are predictive of business students\u27 perceptions of some of the basic problems of philosophy. Understanding the influence of religion affiliation, upbringing, profession, and college major on students\u27 perceptions of right and wrong decision making can be useful for educators when planning for ethics instruction in business education
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Communication interventions to promote the public's awareness of antibiotics: a systematic review.
BackgroundInappropriate antibiotic use is implicated in antibiotic resistance and resultant morbidity and mortality. Overuse is particularly prevalent for outpatient respiratory infections, and perceived patient expectations likely contribute. Thus, various educational programs have been implemented to educate the public.MethodsWe systematically identified public-directed interventions to promote antibiotic awareness in the United States. PubMed, Google Scholar, Embase, CINAHL, and Scopus were queried for articles published from January 1996 through January 2016. Two investigators independently assessed titles and abstracts of retrieved articles for subsequent full-text review. References of selected articles and three review articles were likewise screened for inclusion. Identified educational interventions were coded for target audience, content, distribution site, communication method, and major outcomes.ResultsOur search yielded 1,106 articles; 34 met inclusion criteria. Due to overlap in interventions studied, 29 distinct educational interventions were identified. Messages were primarily delivered in outpatient clinics (N = 24, 83%) and community sites (N = 12, 41%). The majority included clinician education. Antibiotic prescription rates were assessed for 22 interventions (76%). Patient knowledge, attitudes, and beliefs (KAB) were assessed for 10 interventions (34%). Similar rates of success between antibiotic prescription rates and patient KAB were reported (73 and 70%, respectively). Patient interventions that did not include clinician education were successful to increase KAB but were not shown to decrease antibiotic prescribing. Three interventions targeted reductions in Streptococcus pneumoniae resistance; none were successful.ConclusionsMessaging programs varied in their designs, and many were multifaceted in their approach. These interventions can change patient perspectives regarding antibiotic use, though it is unclear if clinician education is also necessary to reduce antibiotic prescribing. Further investigations are needed to determine the relative influence of interventions focusing on patients and physicians and to determine whether these changes can influence rates of antibiotic resistance long-term
Determination of energy barrier profiles for high-k dielectric materials utilizing bias-dependent internal photoemission
We utilize bias-dependent internal photoemission spectroscopy to determine the metal/dielectric/silicon energy barrier profiles for Au/HfO2/Si and Au/Al2O3/Si structures. The results indicate that the applied voltage plays a large role in determining the effective barrier height and we attribute much of the variation in this case to image potential barrier lowering in measurements of single layers. By measuring current at both positive and negative voltages, we are able to measure the band offsets from Si and also to determine the flatband voltage and the barrier asymmetry at 0 V. Our SiO2 calibration sample yielded a conduction band offset value of 3.03+/-0.1 eV. Measurements on HfO2 give a conduction band offset value of 2.7+/-0.2 eV (at 1.0 V) and Al2O3 gives an offset of 3.3+/-0.1 (at 1.0 V). We believe that interfacial SiO2 layers may dominate the electron transport from silicon for these films. The Au/HfO2 barrier height was found to be 3.6+/-0.1 eV while the Au/Al2O3 barrier is 3.5+/-0.1 eV
Safety, tolerability, and efficacy of fixed combination therapy with dorzolamide hydrochloride 2% and timolol maleate 0.5% in glaucoma and ocular hypertension.
Glaucoma is a collection of diseases characterized by multifactorial progressive changes leading to visual field loss and optic neuropathy most frequently due to elevated intraocular pressure (IOP). The goal of treatment is the lowering of the IOP to prevent additional optic nerve damage. Treatment usually begins with topical pharmacological agents as monotherapy, progresses to combination therapy with agents from up to 4 different classes of IOP-lowering medications, and then proceeds to laser or incisional surgical modalities for refractory cases. The fixed combination therapy with the carbonic anhydrase inhibitor dorzolamide hydrochloride 2% and the beta blocker timolol maleate 0.5% is now available in a generic formulation for the treatment of patients who have not responded sufficiently to monotherapy with beta adrenergic blockers. In pre- and postmarketing clinical studies, the fixed combination dorzolamide-timolol has been shown to be safe and efficacious, and well tolerated by patients. The fixed combination dorzolamide-timolol is convenient for patients, reduces their dosing regimen with the goal of increasing their compliance, reduces the effects of washout when instilling multiple drops, and reduces the preservative burden by reducing the number of drops administered per day
A Half Century of Crop Rotation
Fifty-three years of crop rotation studies, started in 1894, were concluded in the fall of 1946. These experiments were on Bridgehampton very fine sandy loam soil that was originally acid and produced meager crops. Within a very few years it became evident that the yields of crops could be materially increased by the use of agricultural lime and chemical fertilizers. The records of the last 17 years of the experiments are reported in this bulletin and comparisons are made with results from former years. The 3 rotations described in this bulletin are known as rotations B, E, and F. B was a 6-year sequence: 1 year of potatoes followed by a year of ensilage corn and 4 years of alfalfa-timothy hay. Rotations E and F were 5-year sequences in which potatoes were followed by Rhode Island White Flint corn and 3 years of hay. Rotation E contained alfalfa, red clover and alsike clover as well as timothy and redtop in the grass seed mixture. The meadow seeding for rotation F consisted of timothy and redtop grasses. The average yields of Irish Cobbler potatoes were: 222 bushels per acre on the clover rotation, 246 bushels per acre on the alfalfa rotation and 294 bushels per acre on the timothy-redtop rotation. The superior yields of potatoes after the non-legume hay is thought to result, in part, from a more favorable supply and balance of potassium, calcium and magnesium left by the grass crop. Rhode Island White Flint corn yielded slightly more grain when grown after the legume-grass hay rather than grass hay alone. The supply of available nitrogen seemed to be a controlling factor influencing the yield of corn. The alfalfa-timothy seeding outyielded the general legume hay mixture during the second and third years. The non-legume seeding produced the smallest amount of hay with the least feed value. The general legume mixture usually produced more hay the first year because the biennial clovers that it contained appeared to mature more quickly than the alfalfa. The average net returns per acre were figured for 2 periods of 5 years, 1935-1939 and 1942-1946. During the first period these net returns per acre were 24.46 and 61.44, 39.85 respectively for these rotations
Progress Towards Real-Time Radiation Measurements on Aircraft
The Space Weather Center (SWC) at Utah State University has created a team to deploy and obtain radiation effective dose rate data from dosimeters flown on commercial aircraft. The objective is to improve the accuracy of radiation dose and dose rate estimates for commercial aviation flight crews. There are two general sources of radiation exposure for flight crews: (1) the ever-present, background galactic cosmic rays (GCR), which originate outside the solar system, and (2) the solar energetic particle (SEP) events (or solar cosmic rays), which are associated with solar flares and coronal mass ejections lasting for several hours to days with widely varying intensity. The Automated Radiation Measurements for Aviation Safety (ARMAS) project is making substantial progress, currently implementing dosimeters flown in commercial aircraft to provide and improve sample data collected for the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) estimates. We report on the results of our flights and the calibration of the dosimeters
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