399 research outputs found

    The Effect of Graded Band Gap Structure Inserted in the Multijunction Solar Cell

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    We have theoretically calculated the photovoltaic conversion efficiency of a monolithic dual-graded junction AlGaAs/GaInAs device, which can be experimentally fabricated. By optimizing the band-gap combination of the considered structure, an improvement of conversion efficiency has been observed in comparison to the conventional AlGaAs/GaInAs system. For the suggested graded band-gap combination, our calculation indicates that the attainable efficiency can be enhanced up to 34% ( AM1.5d). Keywords: band gap gradient, multijunction solar cells, AlGaAs, GaInA

    Blended Learning: How do you optimise undergraduate student engagement?

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    Background: Blended learning is a combination of online and face-to-face learning and is increasingly of interest for use in undergraduate medical education. It has been used to teach clinical post-graduate students pharmacology but needs evaluation for its use in teaching pharmacology to undergraduate medical students, which represent a different group of students with different learning needs. Methods: An existing BSc-level module on neuropharmacology was redesigned using the Blended Learning Design Tool (BLEnDT), a tool which uses learning domains (psychomotor, cognitive and affective) to classify learning outcomes into those taught best by self-directed learning (online) or by collaborative learning (face-to-face). Two online courses were developed, one on Neurotransmitters and the other on Neurodegenerative Conditions. These were supported with face-to-face tutorials. Undergraduate students’ engagement with blended learning was explored by the means of three focus groups, the data from which were analysed thematically. Results: Five major themes emerged from the data 1) Purpose and Acceptability 2) Structure, Focus and Consolidation 3) Preparation and workload 4) Engagement with e-learning component 5) Future Medical Education. Conclusion: Blended learning was acceptable and of interest to undergraduate students learning this subject. They expressed a desire for more blended learning in their courses, but only if it was highly structured, of high quality and supported by tutorials. Students identified that the ’blend’ was beneficial rather than purely online learning

    Petition for Writ of Certiorari, Kosilek v. O\u27Brien

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    Jennifer Levi, on behalf of Gay & Lesbian Advocates & Defenders, was one of the Authors of the Petition for Writ of Certiorari, filed in the Supreme Court of the United States on behalf of the Petitioner, Michelle Kosilek, in Kosilek v. O\u27Brien. Questions presented to the Court by the Petitioner were 1.) whether appellate courts must parse “ques­tions that present elements both factual and legal” into their factual and legal components, so that all factual findings can be reviewed for clear error, or whether, as the First Circuit ruled, they may review such questions as a whole along a “continuum” of deference, where the degree of deference given to the district court is of “variable exactitude,” and 2.) whether the Eighth Amendment prohibits prison officials from denying necessary medical treatment to a prisoner for non-medical reasons, such as security concerns

    Role of circulating polyunsaturated fatty acids on cardiovascular diseases risk:analysis using Mendelian randomization and fatty acid genetic association data from over 114,000 UK Biobank participants

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    BACKGROUND: Despite early interest in the health effects of polyunsaturated fatty acids (PUFA), there is still substantial controversy and uncertainty on the evidence linking PUFA to cardiovascular diseases (CVDs). We investigated the effect of plasma concentration of omega-3 PUFA (i.e. docosahexaenoic acid (DHA) and total omega-3 PUFA) and omega-6 PUFA (i.e. linoleic acid and total omega-6 PUFA) on the risk of CVDs using Mendelian randomization. METHODS: We conducted the largest genome-wide association study (GWAS) of circulating PUFA to date including a sample of 114,999 individuals and incorporated these data in a two-sample Mendelian randomization framework to investigate the involvement of circulating PUFA on a wide range of CVDs in up to 1,153,768 individuals of European ancestry (i.e. coronary artery disease, ischemic stroke, haemorrhagic stroke, heart failure, atrial fibrillation, peripheral arterial disease, aortic aneurysm, venous thromboembolism and aortic valve stenosis). RESULTS: GWAS identified between 46 and 64 SNPs for the four PUFA traits, explaining 4.8–7.9% of circulating PUFA variance and with mean F statistics >100. Higher genetically predicted DHA (and total omega-3 fatty acids) concentration was related to higher risk of some cardiovascular endpoints; however, these findings did not pass our criteria for multiple testing correction and were attenuated when accounting for LDL-cholesterol through multivariable Mendelian randomization or excluding SNPs in the vicinity of the FADS locus. Estimates for the relation between higher genetically predicted linoleic acid (and total omega-6) concentration were inconsistent across different cardiovascular endpoints and Mendelian randomization methods. There was weak evidence of higher genetically predicted linoleic acid being related to lower risk of ischemic stroke and peripheral artery disease when accounting by LDL-cholesterol. CONCLUSIONS: We have conducted the largest GWAS of circulating PUFA to date and the most comprehensive Mendelian randomization analyses. Overall, our Mendelian randomization findings do not support a protective role of circulating PUFA concentration on the risk of CVDs. However, horizontal pleiotropy via lipoprotein-related traits could be a key source of bias in our analyses. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12916-022-02399-w

    Refresh Triggered Computation: Improving the Energy Efficiency of Convolutional Neural Network Accelerators

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    To employ a Convolutional Neural Network (CNN) in an energy-constrained embedded system, it is critical for the CNN implementation to be highly energy efficient. Many recent studies propose CNN accelerator architectures with custom computation units that try to improve energy-efficiency and performance of CNNs by minimizing data transfers from DRAM-based main memory. However, in these architectures, DRAM is still responsible for half of the overall energy consumption of the system, on average. A key factor of the high energy consumption of DRAM is the refresh overhead, which is estimated to consume 40% of the total DRAM energy. In this paper, we propose a new mechanism, Refresh Triggered Computation (RTC), that exploits the memory access patterns of CNN applications to reduce the number of refresh operations. We propose three RTC designs (min-RTC, mid-RTC, and full-RTC), each of which requires a different level of aggressiveness in terms of customization to the DRAM subsystem. All of our designs have small overhead. Even the most aggressive RTC design (i.e., full-RTC) imposes an area overhead of only 0.18% in a 16 Gb DRAM chip and can have less overhead for denser chips. Our experimental evaluation on six well-known CNNs show that RTC reduces average DRAM energy consumption by 24.4% and 61.3%, for the least aggressive and the most aggressive RTC implementations, respectively. Besides CNNs, we also evaluate our RTC mechanism on three workloads from other domains. We show that RTC saves 31.9% and 16.9% DRAM energy for Face Recognition and Bayesian Confidence Propagation Neural Network (BCPNN), respectively. We believe RTC can be applied to other applications whose memory access patterns remain predictable for a sufficiently long time

    Collection of genetic data at scale for a nationally representative population:the UK Millennium Cohort Study

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    A DNA bank has been created from the Millennium Cohort Study (MCS) saliva samples. A total of 23,336 samples are available, from 9,259 cohort members (4,630 males and 4,629 females), 8,898 mothers and 5,179 fathers. There are 4,533 mother, child, father ‘triads’. This paper describes the collection of the saliva samples from cohort members and their biological parents in the MCS. It analyses response rates and predictors of response, and details the DNA extraction, genotyping and imputation procedures performed on the data
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