505 research outputs found

    Ultra-Portable Field Transfer Radiometer for Vicarious Calibration of Earth Imaging Sensors

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    A small portable transfer radiometer has been developed as part of an effort to ensure the quality of upwelling radiance from test sites used for vicarious calibration in the solar reflective. The test sites are used to predict top-of-atmosphere reflectance relying on ground-based measurements of the atmosphere and surface. The portable transfer radiometer is designed for one-person operation for on-site field calibration of instrumentation used to determine ground-leaving radiance. The current work describes the detector-and source-based radiometric calibration of the transfer radiometer highlighting the expected accuracy and SI-traceability. The results indicate differences between the detector-based and source-based results greater than the combined uncertainties of the approaches. Results from recent field deployments of the transfer radiometer using a solar radiation based calibration agree with the source-based laboratory calibration within the combined uncertainties of the methods. The detector-based results show a significant difference to the solar-based calibration. The source-based calibration is used as the basis for a radiance-based calibration of the Landsat-8 Operational Land Imager that agrees with the OLI calibration to within the uncertainties of the methods

    Strengths Technology

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    While the language of positive psychology can be universal, there is a language that organizations gravitate towards and find both engaging and effectual. Organizations speak in terms of behavioral competence when recruiting, assessing performance, measuring results, creating development plans and administering performance appraisals. The current positive psychology canon of self-assessment surveys does not include one that relates to behavioral strengths. We suggest such an assessment, and produce evidence to establish its rightful place. Peterson and Seligman’s Character Strengths and Values (2004) can be operationalized to align with the heuristics of for-profit organizations by connecting the two. We combine positive psychology concepts and scientific research with a proven operational methodology, the Lifo Orientations (Lifo®) Method – to produce Strengths Technology, a more pragmatic strengths-based framework. This proposed framework is comprised of two components, 1) identification of the behaviors that are the expression of VIA Character Strengths and 2) the Strengths Technology Matrix, which outlines 12 strength development strategies. Strengths Technology is a more practical and usable strengths-based framework that will help individuals, teams and organizations discover, capitalize on, and increase their strengths

    Economic Transmission Augmentation With Explicit Modeling of the Competition Benefit

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    This paper derives and evaluates a mathematical structure for identifying economically-efficient transmission augmentations. The mathematical structure is based on the concepts of sequential-move and simultaneous-move games in applied mathematics. The Nash equilibrium solution concept has been reformulated as an optimization problem in the proposed structure. The problem of multiple Nash equilibria is managed by introducing the concept of the worst-case Nash equilibrium. Both the economic concepts of the "efficiency benefit" and "competition benefit" of the transmission capacity are explicitly modeled in the proposed structure. A simple three-bus example system and Garver's example system are employed and modified to suit the purpose of analysis. A thorough economic study of these example systems is presented to highlight the concept and operation of the proposed mathematical structure from different perspectives. The results demonstrate the utility of the proposed structure for measuring the total economic efficiency benefit of additional transmission capacity

    Derivation of a mathematical structure for market-based transmission augmentation in oligopoly electricity markets using multilevel programming

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    In this paper, we derive and evaluate a new mathematical structure for market-based augmentation of the transmission system. The closed-form mathematical structure can capture both the efficiency benefit and competition benefit of the transmission capacity. The Nash solution concept is employed to model the price-quantity game among GenCos. The multiple Nash equilibria of the game are located through a characterisation of the problem in terms of minima of the R function. The worst Nash equilibrium is used in the mechanism of transmission augmentation. The worst Nash equilibrium is defined as the one which maximises the social cost, total generation cost + total value of lost load. Thorough analysis of a simple three-node network is presented to clearly highlight the mechanism of the derived mathematical structure from different perspectives

    Phenotypic Variation and Bistable Switching in Bacteria

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    Microbial research generally focuses on clonal populations. However, bacterial cells with identical genotypes frequently display different phenotypes under identical conditions. This microbial cell individuality is receiving increasing attention in the literature because of its impact on cellular differentiation, survival under selective conditions, and the interaction of pathogens with their hosts. It is becoming clear that stochasticity in gene expression in conjunction with the architecture of the gene network that underlies the cellular processes can generate phenotypic variation. An important regulatory mechanism is the so-called positive feedback, in which a system reinforces its own response, for instance by stimulating the production of an activator. Bistability is an interesting and relevant phenomenon, in which two distinct subpopulations of cells showing discrete levels of gene expression coexist in a single culture. In this chapter, we address techniques and approaches used to establish phenotypic variation, and relate three well-characterized examples of bistability to the molecular mechanisms that govern these processes, with a focus on positive feedback.

    Re A (A Child) and the United Kingdom Code of Practice for the Diagnosis and Confirmation of Death: Should a Secular Construct of Death Override Religious Values in a Pluralistic Society?

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    The determination of death by neurological criteria remains controversial scientifically, culturally, and legally, worldwide. In the United Kingdom, although the determination of death by neurological criteria is not legally codified, the Code of Practice of the Academy of Medical Royal Colleges is customarily used for neurological (brainstem) death determination and treatment withdrawal. Unlike some states in the US, however, there are no provisions under the law requiring accommodation of and respect for residents’ religious rights and commitments when secular conceptions of death based on medical codes and practices conflict with a traditional concept well-grounded in religious and cultural values and practices. In this article, we analyse the medical, ethical, and legal issues that were generated by the recent judgement of the High Court of England and Wales in Re: A (A Child) [2015] EWHC 443 (Fam). Mechanical ventilation was withdrawn in this case despite parental religious objection to a determination of death based on the code of practice. We outline contemporary evidence that has refuted the reliability of tests of brainstem function to ascertain the two conjunctive clinical criteria for the determination of death that are stipulated in the code of practice: irreversible loss of capacity for consciousness and somatic integration of bodily biological functions

    Laboratory investigation on freeze separation of saline mine waste water

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    Abstract: The extraction and upgrading process for bitumen from oil sand deposits in Alberta, Canada currently requires large volumes of process water. This water demand is fulfilled by importing water and recycling/reuse of clarified process water. Reuse of the clarified water results in the steady increase of organic and inorganic (salt) contaminant concentrations in the recycle water. Using a specially designed flume housed in a cold room, trickle freeze separation was evaluated for contaminant separation of saline solutions used as a surrogate for mine waste water. Experiments were conducted at various ambient temperatures, salt concentrations and mass flow rates. Melting proved to be more effective at concentrating salts than freezing. The trickle freeze/thaw process developed during the experiment was very effective at separating and concentrating the salts into a smaller volume. For source waters frozen at an ambient temperature of -15 degrees C and with 3000 mg/L (NaCl) or less, 80% removal of salts was possible after melting 9% of the produced ice. For source waters with higher concentrations (20,000 mg/L), 80% removal was possible after melting 27% of the produced ice

    Pilot randomized trial of therapeutic hypothermia with serial cranial ultrasound and 18-22 month follow-up for neonatal encephalopathy in a low resource hospital setting in Uganda: study protocol

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    Background: There is now convincing evidence that in industrialized countries therapeutic hypothermia for perinatal asphyxial encephalopathy increases survival with normal neurological function. However, the greatest burden of perinatal asphyxia falls in low and mid-resource settings where it is unclear whether therapeutic hypothermia is safe and effective.Aims: Under the UCL Uganda Women's Health Initiative, a pilot randomized controlled trial in infants with perinatal asphyxia was set up in the special care baby unit in Mulago Hospital, a large public hospital with similar to 20,000 births in Kampala, Uganda to determine:(i) The feasibility of achieving consent, neurological assessment, randomization and whole body cooling to a core temperature 33-34 degrees C using water bottles(ii) The temperature profile of encephalopathic infants with standard care(iii) The pattern, severity and evolution of brain tissue injury as seen on cranial ultrasound and relation with outcome(iv) The feasibility of neurodevelopmental follow-up at 18-22 months of ageMethods/Design: Ethical approval was obtained from Makerere University and Mulago Hospital. All infants were in-born. Parental consent for entry into the trial was obtained. Thirty-six infants were randomized either to standard care plus cooling (target rectal temperature of 33-34 degrees C for 72 hrs, started within 3 h of birth) or standard care alone. All other aspects of management were the same. Cooling was performed using water bottles filled with tepid tap water (25 degrees C). Rectal, axillary, ambient and surface water bottle temperatures were monitored continuously for the first 80 h. Encephalopathy scoring was performed on days 1-4, a structured, scorable neurological examination and head circumference were performed on days 7 and 17. Cranial ultrasound was performed on days 1, 3 and 7 and scored. Griffiths developmental quotient, head circumference, neurological examination and assessment of gross motor function were obtained at 18-22 months.Discussion: We will highlight differences in neonatal care and infrastructure that need to be taken into account when considering a large safety and efficacy RCT of therapeutic hypothermia in low and mid resource settings in the future

    Cardiac-sparing radiotherapy for locally advanced non-small cell lung cancer

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    Background We have carried out a study to determine the scope for reducing heart doses in photon beam radiotherapy of locally advanced non-small cell lung cancer (LA-NSCLC). Materials and methods Baseline VMAT plans were created for 20 LA-NSCLC patients following the IDEAL-CRT isotoxic protocol, and were re-optimized after adding an objective limiting heart mean dose (MDHeart). Reductions in MDHeart achievable without breaching limits on target coverage or normal tissue irradiation were determined. The process was repeated for objectives limiting the heart volume receiving ≥ 50 Gy (VHeart-50-Gy) and left atrial wall volume receiving ≥ 63 Gy (VLAwall-63-Gy). Results Following re-optimization, mean MDHeart, VHeart-50-Gy and VLAwall-63-Gy values fell by 4.8 Gy and 2.2% and 2.4% absolute respectively. On the basis of associations observed between survival and cardiac irradiation in an independent dataset, the purposefully-achieved reduction in MDHeart is expected to lead to the largest improvement in overall survival. It also led to useful knock-on reductions in many measures of cardiac irradiation including VHeart-50-Gy and VLAwall-63-Gy, providing some insurance against survival being more strongly related to these measures than to MDHeart. The predicted hazard ratio (HR) for death corresponding to the purposefully-achieved mean reduction in MDHeart was 0.806, according to which a randomized trial would require 1140 patients to test improved survival with 0.05 significance and 80% power. In patients whose baseline MDHeart values exceeded the median value in a published series, the average MDHeart reduction was particularly large, 8.8 Gy. The corresponding predicted HR is potentially testable in trials recruiting 359 patients enriched for greater MDHeart values. Conclusions Cardiac irradiation in RT of LA-NSCLC can be reduced substantially. Of the measures studied, reduction of MDHeart led to the greatest predicted increase in survival, and to useful knock-on reductions in other cardiac irradiation measures reported to be associated with survival. Potential improvements in survival can be trialled more efficiently in a population enriched for patients with greater baseline MDHeart levels, for whom larger reductions in heart doses can be achieved
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