8,510 research outputs found
Plasmonic Gold Nanostars Incorporated into High-Efficiency Perovskite Solar Cells
Incorporating appropriate plasmonic nanostructures into photovoltaic (PV) systems is of great utility for enhancing photon absorption and thus improving device performance. Herein, the successful integration of plasmonic gold nanostars (AuNSs) into mesoporous TiO2 photoelectrodes for perovskite solar cells (PSCs) is reported. The PSCs fabricated with TiO2-AuNSs photoelectrodes exhibited a device efficiency of up to 17.72â%, whereas the control cells without AuNSs showed a maximum efficiency of 15.19â%. We attribute the origin of increased device performance to enhanced light absorption and suppressed charge recombination
Views on and Practices of Integrating Theory and Practice in Teacher Education Programs in Atlantic Canada
The need for and lack of integration of theory and practice in initial teacher education programs has been discussed as a central issue for teacher education. This article reports on a study that surveyed university-based teacher educators in Atlantic Canada on their perspectives regarding how theory and practice can be integrated, how they and the programs they work in integrate theory and practice, and what challenges they perceive for the integration of theory and practice in their own teaching and the teacher education programs within which they work. Un enjeu central qui ressort des discussions sur la formation des enseignants est le besoin dâintĂ©grer la thĂ©orie et la pratique dans les programmes de formation initiale. Cet article rend compte dâune Ă©tude impliquant une enquĂȘte auprĂšs de formateurs universitaires dâenseignants dans le Canada atlantique pour connaitre leur points de vue sur les façons dâintĂ©grer la thĂ©orie et la pratique, et sur les dĂ©fis quâils perçoivent pour lâintĂ©gration de la thĂ©orie et la pratique dans leur propre enseignement et dans les programmes de formation des enseignants au sein desquels ils travaillent
NiO Nanofibers as a Candidate for a Nanophotocathode
p-type NiO nanofibers have been synthesized from a simple electrospinning and sintering procedure. For the first time, p-type nanofibers have been electrospun onto a conductive fluorine doped tin oxide (FTO) surface. The properties of the NiO nanofibers have been directly compared to that of bulk NiO nanopowder. We have observed a p-type photocurrent for a NiO photocathode fabricated on an FTO substrate
Absence of skew scattering in two-dimensional systems: Testing the origins of the anomalous Hall effect
We study the anomalous Hall conductivity in spin-polarized, asymmetrically
confined two-dimensional electron and hole systems, focusing on skew-scattering
contributions to the transport. We find that the skew scattering, principally
responsible for the extrinsic contribution to the anomalous Hall effect,
vanishes for the two-dimensional electron system if both chiral Rashba subbands
are partially occupied, and vanishes always for the two-dimensional hole gas
studied here, regardless of the band filling. Our prediction can be tested with
the proposed coplanar two-dimensional electron/hole gas device and can be used
as a benchmark to understand the crossover from the intrisic to the extrinsic
anomalous Hall effect.Comment: 4 pages, 2 figures include
âReal-lifeâ reduction in cholesterol with statins, 1993 to 2002
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: * Statins reduce cholesterol concentrations and cardiovascular events in randomized clinical trials. * Much less is known about their impact in the setting of normal care. WHAT THIS STUDY ADDS: * This is the first study to assess the effectiveness of lipid-lowering treatment in the general population. * We have also estimated the resultant impact on major vascular events. * We have examined the actual and potential impact of lipid-lowering treatment. AIMS: To evaluate the impact of lipid-lowering treatment on cholesterol concentrations in the setting of normal care. METHODS: This was a retrospective review of all cholesterol measurements made in Tayside, Scotland, between 1993 and 2002, linked to dispensed prescribing data for lipid-lowering drugs. It was conducted in the setting of normal care and included all patients who underwent cholesterol measurement. The main outcome measure was cholesterol concentration. RESULTS: A total of 401,489 cholesterol measurements were made on 128,240 patients over the study period. Measurements were categorized as treated and untreated according to whether patients were exposed to lipid-lowering treatment at the time the total cholesterol concentration was measured. Those categorized as untreated fell by 0.86 mmol l(-1) (13.9%) and those categorized as treated by 1.45 mmol l(-1) (23.5%). The difference between baseline and follow-up cholesterol concentrations in intention-to-treat patients was 1.53 mmol l(-1) (24%) in 2002. In the same year, mean cholesterol concentration was 4.71 mmol l(-1) (a fall of 1.65 mmol l(-1) or 25.9%) in patients judged to be taking their lipid-lowering medication, compared with 5.20 mmol l(-1) (a fall of 1.16 mmol l(-1) or 18.2%) in those judged not to be taking treatment. Cholesterol fell by 0.38 mmol l(-1) (6.3%) in a cohort of never treated patients (n = 33,679) between 1993 and 2002. CONCLUSIONS: The impact of lipid-lowering drugs on population cholesterol concentrations in the setting of normal care was significant and comparable with the cholesterol reductions seen in the setting of major statin trials, despite a significant proportion of the population receiving low dose treatment. In those subjects judged to be taking their medication, the benefits achieved were substantial. The impact of nondrug factors is indicated by the fall in population cholesterol seen in the absence of lipid-lowering treatment
Diagonalization of an Integrable Discretization of the Repulsive Delta Bose Gas on the Circle
We introduce an integrable lattice discretization of the quantum system of n
bosonic particles on a ring interacting pairwise via repulsive delta
potentials. The corresponding (finite-dimensional) spectral problem of the
integrable lattice model is solved by means of the Bethe Ansatz method. The
resulting eigenfunctions turn out to be given by specializations of the
Hall-Littlewood polynomials. In the continuum limit the solution of the
repulsive delta Bose gas due to Lieb and Liniger is recovered, including the
orthogonality of the Bethe wave functions first proved by Dorlas (extending
previous work of C.N. Yang and C.P. Yang).Comment: 25 pages, LaTe
Mapping the distribution of the Sunda pangolin (Manis javanica) within natural forest in Sabah, Malaysian Borneo
Pangolins are the most trafficked mammals in the world and are severely threatened by poaching the loss, degradation, and fragmentation of habitat. In Malaysian Borneo, conservation initiatives for the Sunda pangolin (Manis javanica) are hindered by a paucity of data on their distribution and population size. Using MaxEnt niche modelling and consolidated species location data, we projected the distribution of Sunda pangolins in Sabah. Additionally, we assessed the accessibility of their forest habitats to humans to understand potential threats. Our model indicated that, as of 2015, approximately half of Sabahâs land area (39,530âŻkmÂČ) is suitable for pangolins, with 43% in protected forests, 38% in production forests, and 19% outside of these areas. Alarmingly, our data suggest that nearly all (91%) of these suitable habitats are relatively easily accessible to poachers. Our findings provide a state-level baseline understanding of Sunda pangolin distribution and assess potential threats in Sabah. These can inform short- and long-term conservation management plans for pangolin to safeguard this critically endangered species
Recent Advances in Ultralow-Pt-Loading Electrocatalysts for the Efficient Hydrogen Evolution
Hydrogen production from water electrolysis provides a green and sustainable route. Platinum (Pt)-based materials have been regarded as efficient electrocatalysts for the hydrogen evolution reaction (HER). However, the large-scale commercialization of Pt-based catalysts suffers from the high cost. Therefore, ultralow-Pt-loading electrocatalysts, which can reach the balance of low cost and high HER performance, have attracted much attention. In this review, representative promising synthetic strategies, including wet chemistry, annealing, electrochemistry, photochemistry, and atomic layer deposition are summarized. Further, the interaction between different electrocatalyst components (transition metals and their derivatives) and Pt is discussed. Notably, this interaction can effectively accelerate the kinetics of the HER, enhancing the catalytic activity. At last, current challenges and future perspectives are briefly discussed
Studying a disease with no home - lessons in trial recruitment from the PATCH II study
<p>Abstract</p> <p>Background</p> <p>Cellulitis is a very common condition that often recurs. The PATCH II study was designed to explore the possibility of preventing future episodes of cellulitis, with resultant cost savings for the NHS. This was the first trial to be undertaken by the UK Dermatology Clinical Trials Network. As such, it was the first to test a recruitment model that involved many busy clinicians each contributing just a few patients.</p> <p>Methods</p> <p>A double-blind randomised controlled trial comparing prophylactic antibiotics (penicillin V) with placebo tablets, for the prevention of repeat episodes of cellulitis of the leg. Primary outcome was time to subsequent recurrence of cellulitis.</p> <p>Results</p> <p>The PATCH II study was closed to recruitment having enrolled 123 participants from a target of 400. Whilst the recruitment period was extended by 12 months, it was not possible to continue beyond this point without additional funds. Many factors contributed to poor recruitment: (i) changes in hospital policy and the introduction of community-based intravenous teams resulted in fewer cellulitis patients being admitted to hospital; ii) those who were admitted were seen by many different specialties, making it difficult for a network of dermatology clinicians to identify suitable participants; and iii) funding for research staff was limited to a trial manager and a trial administrator at the co-ordinating centre. With no dedicated research nurses at the recruiting centres, it was extremely difficult to maintain momentum and interest in the study. Attempts to boost recruitment by providing some financial support for principal investigators to employ local research staff was of limited success.</p> <p>Discussion</p> <p>The model of a network of busy NHS clinicians all recruiting a few patients into large clinical studies requires further testing. It did not work very well for PATCH II, but this was probably because patients were not routinely seen by dermatologists, and recruitment took place prior to research support being available through the Comprehensive Clinical Research Network (CCRN). There is a balance to be struck between asking a lot of centres to recruit just a few patients, and asking a few centres to recruit a lot of patients. Giving modest funds to principal investigators to buy local research nurse time did not work well, probably because too little research time was bought, and it was difficult to separate research tasks from the nurses existing clinical duties. National research infrastructure networks such as the Comprehensive Clinical Research Network will overcome many of the problems encountered in the PATCH II trial.</p> <p>Trial Registration</p> <p>The trial registration number is ISRCTN03813200.</p
Percutaneous fixation of posterior malleolar fractures in patients with unstable ankle fractures treated with a fibular intramedullary nail:a description of a technique and review of outcomes
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