918 research outputs found

    Photovoltaic cells energy performance enhancement with down-converting photoluminescence phosphors

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    Phosphors, synthesized by the urea homo-precipitation method, were examined as ultraviolet-spectral down conversion materials for improving the light absorption and electrical characteristics of commercial single-junction silicon solar cells. The photovoltaic (PV) cells were coated with erbium and terbium doped gadolinium oxysulfide phosphors encapsulated in ethyl vinyl-acetate binder using blade screen printing technique, and the optimum concentration of phosphor in the composite resulted in the largest light conversion, and superior electrical output and energy transfer efficiency. Moreover, the results demonstrated that the composition of dispersed phosphors has a strong influence on the amount of ultraviolet-light converted and electron transition capacity of PV cells. The experimental results showed in an optimized PV cell, an enhancement of 0.54% (from 12.11% to 12.65%) in the energy conversion of a Si-based PV cell was achieved.Mr. Ben Parker of LOT-QuantumDesig

    Glyfosaat in stedelijk oppervlaktewater

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    Veel gemeentes en bedrijven gebruiken chemische onkruidbestrijdingsmiddelen (herbiciden) voor de bestrijding van onkruid op verhardingen. Door afspoeling van hemelwater komt een deel van het gebruikte glyfosaat in het oppervlaktewater terecht. Dit kan leiden tot piekconcentraties in het stedelijk oppervlaktewater. Omdat er nog maar weinig meetgegevens van glyfosaat in stedelijk water beschikbaar zijn, hebben de Gelderse waterschappen samen met vier gemeenten gedurende de zomer van 2009 een indicatieve meetcampagne uitgevoerd naar de aanwezigheid van glyfosaat in het stedelijke oppervlaktewater. Hierbij zijn verrassend hoge concentraties glyfosaat aangetroffen

    Геотемпературный режим баженовской свиты и нефтеперспективные зоны меловых отложений (Нюрольская мегавпадина)

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    По замерам пластовых температур верхнеюрских отложений построена карта распределения геотемператур баженовской свиты Нюрольской мегавпадины и структур ее обрамления. По геотемпературному критерию выделены очаги интенсивной генерации баженовских нефтей. Местоположения эпицентров очагов рекомендованы в качестве первоочередных зон для выявления объектов в меловом нефтегазоносном комплексе

    A Miniaturized Multi Sensor Array for Balloon-Borne Air Measurements, Phase I

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    Weber State University’s High-Altitude Ballooning team, HARBOR, has seen an opportunity for cooperative research among the many individual balloon teams based in North America. The Great American Solar Eclipse brought these teams into the spotlight as dozens of ballooning groups worked together to image the eclipse. Leveraging this collection of balloon teams to create a large-scale data set could make some valuable discoveries and give us a better understanding of the atmospheric dynamics that take place in the stratosphere. Our team has decided to facilitate the creation of such a data set by designing an atmospheric data collection tool, the mini-Multi Sensor Array, that can be flown by teams all over the nation, and potentially the world. Our goal is to create an inexpensive, lightweight, easy to assemble device which will measure gas concentrations, particulate matter, atmospheric turbulence, and meteorological parameters such as temperature, pressure, and humidity. We will also add features such as long distance telemetry, which will facilitate recovery of these payloads. Having a redundant, lightweight tracking device will increase the number of flight teams that are making a regular effort to fly our mini-MSA with their payload

    Immunocytochemical and electrophysiological characterization of GABA receptors in the frog and turtle retina

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    AbstractThe expression of GABA receptors (GABARs) was studied in frog and turtle retinae. Using immunocytochemical methods, GABAARs and GABACRs were preferentially localized to the inner plexiform layer (IPL). Label in the IPL was punctate indicating a synaptic clustering of GABARs. Distinct, but weaker label was also present in the outer plexiform layer. GABAAR and GABACR mediated effects were studied by recording electroretinograms (ERGs) and by the application of specific antagonists. Bicuculline, the GABAAR antagonist, produced a significant increase of the ERG. Picrotoxin, when co-applied with saturating doses of bicuculline, caused a further increase of the ERG due to blocking of GABACRs. The putative GABACR antagonist Imidazole-4-acidic acid (I4AA) failed to antagonize GABACR mediated inhibition and, in contrast, appeared rather as an agonist of GABARs

    Metagenomic and geochemical characterization of pockmarked sediments overlaying the Troll petroleum reservoir in the North Sea

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    Background Pockmarks (depressions in the seabed) have been discovered throughout the world’s oceans and are often related to hydrocarbon seepage. Although high concentrations of pockmarks are present in the seabed overlaying the Troll oil and gas reservoir in the northern North Sea, geological surveys have not detected hydrocarbon seepage in this area at the present time. In this study we have used metagenomics to characterize the prokaryotic communities inhabiting the surface sediments in the Troll area in relation to geochemical parameters, particularly related to hydrocarbon presence. We also investigated the possibility of increased potential for methane oxidation related to the pockmarks. Five metagenomes from pockmarks and plain seabed sediments were sequenced by pyrosequencing (Roche/454) technology. In addition, two metagenomes from seabed sediments geologically unlikely to be influenced by hydrocarbon seepage (the Oslofjord) were included. The taxonomic distribution and metabolic potential of the metagenomes were analyzed by multivariate analysis and statistical comparisons to reveal variation within and between the two sampling areas. Results The main difference identified between the two sampling areas was an overabundance of predominantly autotrophic nitrifiers, especially Nitrosopumilus, and oligotrophic marine Gammaproteobacteria in the Troll metagenomes compared to the Oslofjord. Increased potential for degradation of hydrocarbons, especially aromatic hydrocarbons, was detected in two of the Troll samples: one pockmark sample and one from the plain seabed. Although presence of methanotrophic organisms was indicated in all samples, no overabundance in pockmark samples compared to the Oslofjord samples supports no, or only low level, methane seepage in the Troll pockmarks at the present time. Conclusions Given the relatively low content of total organic carbon and great depths of hydrocarbon containing sediments in the Troll area, it is possible that at least part of the carbon source available for the predominantly autotrophic nitrifiers thriving in this area originates from sequential prokaryotic degradation and oxidation of hydrocarbons to CO2. By turning CO2 back into organic carbon this subcommunity could play an important environmental role in these dark oligotrophic sediments. The oxidation of ammonia to nitrite and nitrate in this process could further increase the supply of terminal electron acceptors for hydrocarbon degradation

    Evaluating a Modular Decision Support Application For Colorectal Cancer Screening

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    BACKGROUND: There is a need for health information technology evaluation that goes beyond randomized controlled trials to include consideration of usability, cognition, feedback from representative users, and impact on efficiency, data quality, and clinical workflow. This article presents an evaluation illustrating one approach to this need using the Decision-Centered Design framework. OBJECTIVE: To evaluate, through a Decision-Centered Design framework, the ability of the Screening and Surveillance App to support primary care clinicians in tracking and managing colorectal cancer testing. METHODS: We leveraged two evaluation formats, online and in-person, to obtain feedback from a range primary care clinicians and obtain comparative data. Both the online and in-person evaluations used mock patient data to simulate challenging patient scenarios. Primary care clinicians responded to a series of colorectal cancer-related questions about each patient and made recommendations for screening. We collected data on performance, perceived workload, and usability. Key elements of Decision-Centered Design include evaluation in the context of realistic, challenging scenarios and measures designed to explore impact on cognitive performance. RESULTS: Comparison of means revealed increases in accuracy, efficiency, and usability and decreases in perceived mental effort and workload when using the Screening and Surveillance App. CONCLUSION: The results speak to the benefits of using the Decision-Centered Design approach in the analysis, design, and evaluation of Health Information Technology. Furthermore, the Screening and Surveillance App shows promise for filling decision support gaps in current electronic health records

    The Harris hip score: Do ceiling effects limit its usefulness in orthopedics?: A systematic review

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    The Harris hip score (HHS), a disease-specific health status scale that is frequently used to measure the outcome of total hip arthroplasty, has never been validated properly. A questionnaire is suitable only when all 5 psychometric properties are of sufficient quality. We questioned the usefulness of the HHS by investigating its content validity. We performed a systematic review based on a literature search in PubMed, Embase, and the Cochrane Library for descriptive studies published in 2007. 54 studies (59 patient groups) met our criteria and were included in the data analysis. To determine the content validity, we calculated the ceiling effect (percentage) for each separate study and we pooled data to measure the weighted mean. A subanalysis of indications for THA was performed to differentiate the populations for which the HHS would be suitable and for which it would not. A ceiling effect of 15% or less was considered to be acceptable. Over half the studies (31/59) revealed unacceptable ceiling effects. Pooled data across the studies included (n = 6,667 patients) suggested ceiling effects of 20% (95%CI: 18-22). Ceiling effects were greater (32%, 95%CI:12-52) in those patients undergoing hip resurfacing arthroplasty. Although the Harris hip score is widely used in arthroplasty research on outcomes, ceiling effects are common and these severely limit its validity in this field of researc

    Awareness and use of intertrochanteric osteotomies in current clinical practice. An international survey

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    Current literature shows that intertrochanteric osteotomies can produce excellent results in selected hip disorders in specific groups of patients. However, it appears that this surgical option is considered an historical one that has no role to play in modern practice. In order to examine current awareness of and views on intertrochanteric osteotomies among international hip surgeons, an online survey was carried out. The survey consisted of a set of questions regarding current clinical practice and awareness of osteotomies. The second part of the survey consisted of five clinical cases and sought to elicit views on preoperative radiological investigations and preferred (surgical) treatments. The results of our survey showed that most of these experts believe that intertrochanteric osteotomies should still be performed in selected cases. Only 56% perform intertrochanteric osteotomies themselves and of those, only 11% perform more than five per year. The responses to the cases show that about 30–40% recommend intertrochanteric osteotomies in young symptomatic patients. This survey shows that the role of intertrochanteric osteotomies is declining in clinical practice
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