351 research outputs found

    A fully integrated autonomous power management system with high power capacity and novel MPPT for thermoelectric energy harvesters in IoT/wearable applications

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    This paper reports a fully integrated autonomous power management system for thermoelectric energy harvesting with application in batteryless IoT/Wearable devices. The novel maximum power point tracking (MPPT) algorithm does not require open circuit voltage measurement. The proposed system delivers 0.5 mA current with 1 V regulated output based on simulations, which is the highest output current for a fully integrated converter reported in the literature for ultra-low voltage applications, to the best knowledge of the authors. Regulated 1 V output can be achieved for load range >2 k Omega, and input voltage range >140 mV. The circuit has been implemented in UMC-180nm standard CMOS technology and simulated

    Uniform Methods Project: Methods for Determining Energy Efficiency Savings for Specific Measures; January 2012 - March 2013

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    Under the Uniform Methods Project, DOE is developing a framework and a set of protocols for determining the energy savings from specific energy efficiency measures and programs. The protocols provide a straightforward method for evaluating gross energy savings for common residential and commercial measures offered in ratepayer-funded initiatives in the United States. They represent a refinement of the body of knowledge supporting energy efficiency evaluation, measurement, and verification (EM&V) activities. This document deals with savings from the following measures: commercial and industrial lighting, commercial and industrial lighting controls, small commercial and residential unitary and split system HVAC cooling equipment, residential furnaces and boilers, residential lighting, refrigerator recycling, whole-building retrofit using billing analysis, metering, peak demand and time-differentiated energy savings, sample design, survey design and implementation, and assessing persistence and other evaluation issues

    The GP Tests of Competence assessment: which part best predicts fitness to practise decisions?

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    BACKGROUND: The General Medical Council (GMC) conducts Tests of Competence (ToC) for doctors referred for Fitness to Practise (FtP) issues. GPs take a single best answer knowledge test, an Objective Structured Clinical Examination (OSCE), and a Simulated Surgery (SimSurg) assessment which is a simulated GP consultation. The aim of this study was to examine the similarities between OSCEs and SimSurg to determine whether each assessment contributed something unique to GP ToCs. METHODS: A mixed methods approach was used. Data were collated on 153 GPs who were required to undertake a ToC as a part of being investigated for FtP issues between February 2010 and October 2016. Using correlation analysis, we examined to what degree performance on the knowledge test, OSCE, and SimSurg related to case examiner recommendations and FtP outcomes, including the unique predictive power of these three assessments. The outcome measures were case examiner recommendations (i) not fit to practise; ii) fit to practise on a limited basis; or iii) fit to practise) as well as FtP outcomes (i) erased/removed from the register; ii) having restrictions/conditions; or iii) be in good standing). For the qualitative component, 45 GP assessors were asked to rate whether they assess the same competencies and which assessment provides better feedback about candidates. RESULTS: There was significant overlap between OSCEs and SimSurg, p < 0.001. SimSurg had additional predictive power in the presence of OSCEs and the knowledge test (p = 0.030) in distinguishing doctors from different FtP categories, while OSCEs did not (p = 0.080). Both the OSCEs (p = 0.004) and SimSurg (p < 0.001) had significant negative correlations with case examiner recommendations when accounting for the effects of the other two assessments. Inductive thematic analysis of the responses to the questionnaire showed that assessors perceived OSCEs to be better suited to target specific knowledge and skills. SimSurg was thought to produce a more global picture as the scenarios more accurately portray a patient consultation. CONCLUSION: While all three assessments are strong predictors of both case examiner recommendations and FtP outcomes, our findings suggest that the efficiency of GP ToCs can be improved by removing some of this overlapping content

    Variations in Thermal Performance across Populations of two Anuran Species from Different Geographical Regions in Sri Lanka

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    The thermal performance of an animal is directly linked to its thermal sensitivity. Information on thermal sensitivity would assume special significance in interpreting the vulnerability of amphibian species to climate change. Ectotherm species with narrow temperature tolerance ranges, would be particularly susceptible to predicted changes in ambient temperature. The present study therefore attempts to assess the degree of thermal sensitivity of two anuaran species. It is expected that the study would provide an insight into the ability of the species to adapt to climate change. Two native anurans, Duttaphrynus melanostictus (common Asian toad) and Euphlyctis cyanophlyctis (Indian skipper frog) were selected as they are widely distributed across the country. Toads and frogs were collected from four locations: Matara-(mean ambient temperature (MAT=30.2° C), Nuwara Eliya (MAT=17.6° C), Colombo (MAT=28.4° C), Polonnaruwa (MAT=34.2° C). The animals were empirically exposed to six test temperatures (between 12° C and 38° C) at field stations in the locations of capture to assess four performance parameters (Jump distance, Righting time, Contact time and Jump force). Thermal Performance Curves (TPCs) were constructed to obtain values for the endpoints-thermal niche breadth (NB), thermal optima (TO) and optimal performance (OP).The TPCs for each species differed considerably across the different populations. Both D. melanostictus and E. cyanophlyctis in cooler areas performed better at lower temperatures, while those from hotter areas performed better at warmer temperatures. Negative skewedness of TPCs show drastic drops in performance once optima is reached. There was good congruence between thermal optima and the MATs of the capture regions (F3, 20=26.87 p&lt;0.05). Niche breadth was narrowest in toads and frogs from the coldest region (Nuwara Eliya). The results were consistent across both species. The findings are in agreement with previous observation for disparities in thermal sensitivity across latitudinal and altitudinal gradients in other anuran species. These trends suggest that amphibian populations show a degree of adaptability to specific ambient temperatures to which they are exposed to in their natural environment, enabling them to perform at an optimal level. It was also noted that in the hottest region (Matara) the thermal optima of E. cyanophlyctis was slightly below the MAT. This and its narrower thermal niche breadth would make it more susceptible to increases in ambient temperature than D. melanostictus.Keywords: Thermal sensitivity, Climate change, Anurans, Ectotherm

    HAWAIIAN SKIRT, and F-box gene from Arabidopsis, is a new player in the microRNA pathway

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    F-box proteins belong to a multi-protein E3 ubiquitin ligase complex (SCF) that target proteins for degradation via the proteasome.We demonstrated that HAWAIIAN SKIRT(HWS), an Arabidopsis ubiquitin protein ligase (SCFHWS), regulates organ growth, flower development and timing of abscission. Mutants of this gene (hws-1) are pleiotropic and the most obvious phenotype is the fusion of its floral organs, a phenotype shared with the cuc1/cuc2 double mutants and over-expressing lines of MIR164B. To understand the molecular mechanisms of HWS during plant development, an ethylmethylsulphonate mutagenized population of hws-1 seeds was generated and screened for mutations suppressing the hws-1 sepal fusion. We isolated shs-1/hws-1, shs-2/hws-1, and shs-3/hws-1, (suppressor of hws-1) mutants. Mapping analyses shown that shs1 is mutated in the miRNA164 binding site of CUPSHAPED COTYLEDON1 (CUC1) mRNA; while shs-2 and shs-3 are novel alleles of the plant homolog of Exporting-5 HASTY (HST), known to be important in miRNA biogenesis, function and transport. Consequently, we renamed them cuc1-1D, hst23 and hst24, respectively. We demonstrated that transcript levels of CUC1 and CUPSHAPED COTYLEDON 2 (CUC2), and MIR164 change in cuc1-1D and in hws-1 mutants; analyses revealed a role for HWS in cell proliferation and control of floral organ number. Additional genetic crosses between hws-1 and mutant lines for genes in the miRNA pathway were performed and double mutants obtained shown restoration of the hws-1 sepal fusion phenotype. Our data propose HWS as a new regulator in miRNA pathway and reveal a role for HWS to control floral organ number and cell proliferation

    The contribution of gestational age, area deprivation and mother's country of birth to ethnic variations in infant mortality in England and Wales: A national cohort study using routinely collected data

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    OBJECTIVES: We aimed to describe ethnic variations in infant mortality and explore the contribution of area deprivation, mother's country of birth, and prematurity to these variations. METHODS: We analyzed routine birth and death data on singleton live births (gestational age≥22 weeks) in England and Wales, 2006-2012. Infant mortality by ethnic group was analyzed using logistic regression with adjustment for sociodemographic characteristics and gestational age. RESULTS: In the 4,634,932 births analyzed, crude infant mortality rates were higher in Pakistani, Black Caribbean, Black African, and Bangladeshi infants (6.92, 6.00, 5.17 and 4.40 per 1,000 live births, respectively vs. 2.87 in White British infants). Adjustment for maternal sociodemographic characteristics changed the results little. Further adjustment for gestational age strongly attenuated the risk in Black Caribbean (OR 1.02, 95% CI 0.89-1.17) and Black African infants (1.17, 1.06-1.29) but not in Pakistani (2.32, 2.15-2.50), Bangladeshi (1.47, 1.28-1.69), and Indian infants (1.24, 1.11-1.38). Ethnic variations in infant mortality differed significantly between term and preterm infants. At term, South Asian groups had higher risks which cannot be explained by sociodemographic characteristics. In preterm infants, adjustment for degree of prematurity (<28, 28-31, 32-33, 34-36 weeks) fully explained increased risks in Black but not Pakistani and Bangladeshi infants. Sensitivity analyses with further adjustment for small for gestational age, or excluding deaths due to congenital anomalies did not fully explain the excess risk in South Asian groups. CONCLUSIONS: Higher infant mortality in South Asian and Black infants does not appear to be explained by sociodemographic characteristics. Higher proportions of very premature infants appear to explain increased risks in Black infants but not in South Asian groups. Strategies targeting the prevention and management of preterm birth in Black groups and suboptimal birthweight and modifiable risk factors for congenital anomalies in South Asian groups might help reduce ethnic inequalities in infant mortality

    Mid-infrared photodetectors operating over an extended wavelength range up to 90 K

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    We report a wavelength threshold extension, from the designed value of 3.1 to 8.9 μm, in a -type heterostructure photodetector. This is associated with the use of a graded barrier and barrier offset, and arises from hole–hole interactions in the detector absorber. Experiments show that using long-pass filters to tune the energies of incident photons gives rise to changes in the intensity of the response. This demonstrates an alternative approach to achieving tuning of the photodetector response without the need to adjust the characteristic energy that is determined by the band structure

    The structural invisibility of outsiders: the role of migrant labour in the meat-processing industry

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    This article examines the role of migrant workers in meat-processing factories in the UK. Drawing on materials from mixed methods research in a number of case study towns across Wales, we explore the structural and spatial processes that position migrant workers as outsiders. While state policy and immigration controls are often presented as a way of protecting migrant workers from work-based exploitation and ensuring jobs for British workers, our research highlights that the situation ‘on the ground’ is more complex. We argue that ‘self-exploitation’ among the migrant workforce is linked to the strategies of employers and the organisation of work, and that hyper-flexible work patterns have reinforced the spatial and social invisibilities of migrant workers in this sector. While this creates problems for migrant workers, we conclude that it is beneficial to supermarkets looking to supply consumers with the regular supply of cheap food to which they have become accustomed

    Rare Events in Remote Dark-Field Spectroscopy: An Ecological Case Study of Insects

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