Search

Abstract Background The beneficial outcomes of oral anticoagulation therapy are dependent upon achieving and maintaining an optimal INR therapeutic range. There is growing evidence that better outcomes are achieved when anticoagulation is managed by a pharmacist with expertise in anticoagulation management rather than usual care by family physicians. This study compared a pharmacist managed anticoagulation program (PC) to usual physician care (UC) in a family medicine clinic. Methods A retrospective cohort study was carried out in a family medicine clinic which included a clinical pharmacist. In 2006, the pharmacist assumed anticoagulation management. For a 17-month period, the PC group (n = 112) of patients on warfarin were compared to the UC patients (n = 81) for a similar period prior to 2006. The primary outcome was the percentage of time patients' INR was in the therapeutic range (TTR). Secondary outcomes were the percentage of time in therapeutic range within ± 0.3 units of the recommended range (expanded TTR) and percentage of time the INR was >5.0 or Results The baseline characteristics were similar between the groups. Fifty-five percent of the PC group was male with a mean age of 67 years; 51% of the UC group was male with a mean age of 71 years. The most common indications for warfarin in both groups were atrial fibrillation, mechanical heart valves and deep vein thrombosis. The TTR was 73% for PC and 65% for UC (p < 0.0001). The expanded TTR for PC was 91% and 85% for UC (p < 0.0001). The percentage of time INR values were 5 were 0.3% for PC patients and 0.1% for UC (p < 0.0001). Conclusion The pharmacist-managed anticoagulation program within a family practice clinic compared to usual care by the physicians achieved significantly better INR control as measured by the percentage of time patients' INR values were kept in both the therapeutic and expanded range. Based on the results of this study, a collaborative family practice clinic using pharmacists and physicians may be an effective model for anticoagulation management with these results verified in future prospective randomized studies.

An oft used approximation to predict quantum efficiency (QE) from bare metals or those with a low work function coating such as cesium is to assume that photo-excited electrons have not scattered prior to their emission. Monte Carlo simulations are used to assess that approximation, and show that, while good for bare metals, for cesiated metals a photoexcited electron may undergo several scattering events and yet be emitted. Neglecting scattered electrons therefore underestimates QE. Emitted electrons that have undergone scattering before emission elongate the response time by giving rise to a long time tail, low energy contribution to the faster non-scattered emission, for which a model is developed. The theory is applied to study variations in QE as a function of wavelength measured from cesiated metal surfaces. The extension of the findings to semiconductor photocathodes is briefly discussed. [ABSTRACT FROM AUTHOR]

A model of photoemission from cesium antimonide (Cs3Sb) that does not rely on adjustable parameters is proposed and compared to the experimental data of Spicer [Phys. Rev. 112, 114 (1958)] and Taft and Philipp [Phys. Rev. 115, 1583 (1959)]. It relies on the following components for the evaluation of all relevant parameters: (i) a multidimensional evaluation of the escape probability from a step-function surface barrier, (ii) scattering rates determined using a recently developed alpha-semiconductor model, and (iii) evaluation of the complex refractive index using a harmonic oscillator model for the evaluation of reflectivity and extinction coefficient. [ABSTRACT FROM AUTHOR]

Passing an electron beam through an aperture can serve to reduce the beam current or change the transverse beam profile. For a sufficiently intense beam, space charge will drive a radial expansion of the beam, which may cause the current passing through the aperture to decrease even though the current arriving at the aperture is increasing. When a gridded electron gun is used, this may be expressed by stating that the transconductance of the apertured gun is negative. Here, we explain this effect and explore some of the key factors governing when it can occur and influencing its strength. [ABSTRACT FROM AUTHOR]

Usable lifetime has long been a limitation of high efficiency photocathodes in high average current accelerator applications such as free electron lasers, where poor vacuum conditions and high incident laser power contribute to early degradation in electron beam emission. Recent progress has been made in adapting well known thermionic dispenser techniques to photocathodes, resulting in a dispenser photocathode whose photosensitive surface coating of cesium can be periodically replenished to extend effective lifetime. This article details the design and fabrication process of a prototype cesium dispenser photocathode and describes in detail the dominant factors affecting its performance: activation procedure, surface cleanliness, temperature, and substrate microstructure. [ABSTRACT FROM AUTHOR]

Photocathodes are a critical component many linear accelerator based light sources. The development of a custom-engineered photocathode based on low work function coatings requires an experimentally validated photoemission model that accounts the complexity of the emission process. We have developed a time-dependent model accounting for the effects of laser heating and thermal propagation on photoemission. It accounts for surface conditions (coating, field enhancement, and reflectivity), laser parameters (duration, intensity, and wavelength), and material characteristics (reflectivity, laser penetration depth, and scattering rates) to predict current distribution and quantum efficiency (QE) as a function of wavelength. The model is validated by (i) experimental measurements of the QE of cesiated surfaces, (ii) the QE and performance of commercial dispenser cathodes (B, M, and scandate), and (iii) comparison to QE values reported in the literature for bare metals and B-type dispenser cathodes, all for various wavelengths. Of particular note is that the highest QE for a commercial (M-type) dispenser cathode found here was measured to be 0.22% at 266 nm, and is projected to be 3.5 times larger for a 5 ps pulse delivering 0.6 mJ/cm2 under a 50 MV/m field. [ABSTRACT FROM AUTHOR]

The article discusses properties and benefits of several sources of the electron beam that are commonly necessary for the free-electron lasers and particle-physics accelerators. The findings state that a source should have proper electric field, as well as a vacuum environment for the acceleration of the electrons.

For the past two years the authors of this article have produced material by their students as wikibooks that became the principal textbooks in education courses they taught undergraduates at Old Dominion University. They have turned other material by their students into units in wikibooks used in business courses they have taught graduate students at the University of Denver. Many of their students prefer the wikibooks to standard textbooks, find them to be credible sources of information, spend more time learning from them than from standard textbooks, enjoy the challenge of contributing to them, and consider their peers' contributions valuable. The authors view student-written wikibooks as instructor-guided excursions into the new intellectual landscape, where expert knowledge is ever more readily accessible. They hope that writing and using wikibooks will help prepare students to navigate future changes in the global production and distribution of information.

In the present study, we have analyzed the spatial patterns of seasonal-scale diurnal cycle of three main pollutants, NO, SO, and O, across five stations in Delhi. We used hourly data collected by the local pollution monitoring agencies for the time period, October 2010 to September 2013. Harmonic analysis was used to detect the diurnal cycle in the observed patterns of pollutants across Delhi. The results of our study indicated a consistently higher level of concentrations of all the pollutants at two of the stations, IGI Airport and Civil Lines, while lower concentration levels were observed in the mixed use residential areas of Shadipur and NSIT Dwarka. A clockwise gradual progression in the time of maximum from east to west was observed in the case of SO during each season. The time of maximum for O for each season was in the early evening hours, 1800 local standard time (LST). Moreover, there were little spatial variations in the peak time of occurrence of NO and O at the seasonal scale. [ABSTRACT FROM AUTHOR]