109 research outputs found

    Radiation resistance of thin-film solar cells for space photovoltaic power

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    Copper indium diselenide, cadmium telluride, and amorphous silicon alloy solar cells have achieved noteworthy performance and are currently being studied for space power applications. Cadmium sulfide cells had been the subject of much effort but are no longer considered for space applications. A review is presented of what is known about the radiation degradation of thin film solar cells in space. Experimental cadmium telluride and amorphous silicon alloy cells are reviewed. Damage mechanisms and radiation induced defect generation and passivation in the amorphous silicon alloy cell are discussed in detail due to the greater amount of experimental data available

    Ultralight amorphous silicon alloy photovoltaic modules for space applications

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    Ultralight and ultrathin, flexible, rollup monolithic PV modules have been developed consisting of multijunction, amorphous silicon alloys for either terrestrial or aerospace applications. The rate of progress in increasing conversion efficiency of stable multijunction and multigap PV cells indicates that arrays of these modules can be available for NASA's high power systems in the 1990's. Because of the extremely light module weight and the highly automated process of manufacture, the monolithic a-Si alloy arrays are expected to be strongly competitive with other systems for use in NASA's space station or in other large aerospace applications

    Consideration of Financial Satisfaction: What Consumers Know, Feel and Do from a Financial Perspective

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    Financial satisfaction has long been considered an important component to consumer life satisfaction and well-being. Using data from the 2012 National Financial Capability Study (NFCS), financial satisfaction is explored in the context of personal characteristics related to financial knowledge (both objective and subjective) as well as self-reported financial behaviors. Ordinary Least Squares Regression is applied to a predictive model of financial satisfaction, and results indicate that measures associated with what people do (behaviors related to recommended practice) and how they feel (subjective knowledge) may be more salient factors to consider with regard to satisfaction than measures related to what individuals know (objective knowledge). Implications are considered for consumers in light of a general policy approach promoting financial literacy and education as a means of improving financial outcomes and well-being

    Investigations To Characterize Multi-Junction Solar Cells In The Stratosphere Using Low-Cost Balloon And Communication Technologies

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    The use of current balloon, control and communication technologies to test multi-junction solar sell in the stratosphere to achieve near AMO conditions have been investigated. The design criteria for the technologies are that they be reliable, low cost and readily available. Progress is reported on a program to design, launch, fly and retrieve payloads dedicated to testing multi-junction solar cells

    \u3ci\u3eClinostomum poteae\u3c/i\u3e n. sp. (Digenea: Clinostomidae), in the trachea of a double-crested cormorant \u3ci\u3ePhalacrocorax auritus\u3c/i\u3e Lesson, 1831 and molecular data linking the life-cycle stages of \u3ci\u3eClinostomum album\u3c/i\u3e Rosser, Alberson, Woodyard, Cunningham, Pote & Griffin, 2017 in Mississippi, USA

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    Clinostomum spp. (Digenea: Clinostomidae) are a group of trematodes commonly found in the buccal cavity and oesophagus of a variety of piscivorous birds. The metacercariae, colloquially known as ‘‘yellow grubs,’’ have been reported from a diverse group of freshwater fishes worldwide. In the catfish farming region of the southeastern USA, piscivorous birds present a continuous challenge for aquaculturists in the form of fish depredation and the introduction of trematodes into these static, earthen pond systems. Clinostomum spp. are commonly encountered in farmraised catfish. While generally considered pests of minimal importance, heavy infections can result in unmarketable fillets. Of the piscivorous birds that frequent catfish aquaculture operations in the southeastern US, the double-crested cormorant (Phalacrocorax auritus Lesson) is one of the most damaging, although reports of Clinostomum spp. from P. auritus are limited. In this study, adult trematodes morphologically consistent with Clinostomum sp. were found in the trachea of a double-crested cormorant captured in Lowndes Co., Mississippi, USA. These specimens differed from other recognised Clinostomum spp. in several key morphological characters. Moreover, sequence data of mitochondrial cytochrome c oxidase subunit 1 gene (cox1), nicotinamide adenine dinucleotide dehydrogenase subunit 1 gene (nad1) and ribosomal internal transcribed spacer (ITS) regions did not match any known Clinostomum sp. for which sequence data are available. While genetically similar to C. marginatum and C. album Rosser, Alberson, Woodyard, Cunningham, Pote & Griffin, 2017 reported from the great egret Ardea alba L. in Mississippi, these adult clinostomids were larger in size and limited to the trachea, whereas both C. marginatum Rudolphi, 1819 and C. album are found in the oral cavity and esophagus. Given these distinct morphological and molecular characters we propose a new member of the genus, known hereafter as Clinostomum poteae n. sp. Additionally, larval stages in the life-cycle of C. album are morphologically and molecularly identified for the first time from ramshorn snails Planorbella trivolvis Say and fathead minnows Pimephales promelas Rafinesque

    Experimental Elucidation of the Life Cycle of \u3ci\u3eDrepanocephalus Spathans\u3c/i\u3e (Digenea: Echinostomatidae) with Notes on the Morphological Plasticity of \u3ci\u3eD. Spathans\u3c/i\u3e in the United States

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    The echinostomatid Drepanocephalus spathans (syn. Drepanocephalus auritus) parasitizes the doublecrested cormorant Phalacrocorax auritus. In North America, the marsh rams-horn snail Planorbella trivolvis and ghost rams-horn snail Biomphalaria havanensis serve as snail intermediate hosts, both of which inhabit catfish aquaculture ponds in the southeastern United States. Studies have demonstrated D. spathans exposure can be lethal to juvenile channel catfish Ictalurus punctatus. Two studies were undertaken to elucidate the life cycle of D. spathans to establish a developmental time line. In both studies, D. spathans cercariae collected from naturally infected P. trivolvis individuals were used to infect channel catfish fingerlings, which were then fed to double-crested cormorants (DCCOs) that had been pharmaceutically dewormed. In study 1, laboratory-reared P. trivolvis and B. havanensis individuals were placed in aviary ponds with experimentally infected DCCO and examined bi-weekly for release of cercariae. Trematode eggs were observed in the feces of exposed birds 3 days post-infection. Birds were sacrificed 18 days post-exposure (dpe), and gravid adults morphologically and molecularly consistent with D. spathans were recovered. Snails from the aviary pond were observed shedding D. spathans cercariae 18–54 dpe. In study 2, trematode eggs were observed in the feces of exposed DCCOs beginning 8 dpe. Once eggs were observed, birds were allowed to defecate into clean tanks containing naı¨ve laboratory-reared P. trivolvis individuals. Additionally, eggs from experimental DCCO feces were recovered by sedimentation and placed in an aquarium housing laboratory-reared P. trivolvis individuals. Birds in study 2 were sacrificed after 60 days, and gravid D. spathans specimens were recovered. Snails from the experimental DCCO tanks shed D. spathans cercariae 89–97 dpe. Lastly, trematode eggs were isolated and observed for the hatching of miracidia, which emerged on average after 16 days at ambient temperatures. No D. spathans adults were observed in control birds fed non-parasitized fish. This is the first experimental confirmation of the D. spathans life cycle, resolving previously unknown developmental time lines. In addition, the effects of fixation on adult trematode morphology were assessed, clarifying reports of pronounced morphological plasticity for D. spathans

    Sex differences in money pathology in the general population

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    This study examined sex differences in money beliefs and behaviours. Over 100,000 British participants completed two measures online, one of which assessed “money pathology” (Forman in Mind over money, Doubleday, Toronto, 1987), and the other four “money types”, based on the emotional associations of money (Furnham et al. in Personal Individ Differ, 52:707–711, 2012). Nearly all measures showed significant sex differences with medium to large effect sizes, and with females exhibiting more “money pathology” than males. The biggest difference on the money types was on money being associated with generosity (money representing love) where men scored much lower than females, and autonomy (money representing freedom) where men scored higher than women. For men, more than women, money represented Power and Security. Men were more likely to be Hoarders while women did more emotional regulatory purchasing. Implications and limitations of this study are discussed

    Bovine pericardium based non-cross linked collagen matrix for successful root coverage, a clinical study in human

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    Introduction: The aim of this study was to clinically assess the capacity of a novel bovine pericardium based, non-cross linked collagen matrix in root coverage. Methods: 62 gingival recessions of Miller class I or II were treated. The matrix was adapted underneath a coronal repositioned split thickness flap. Clinical values were assessed at baseline and after six months. Results: The mean recession in each patient was 2.2 mm at baseline. 6 Months after surgery 86.7% of the exposed root surfaces were covered. On average 0,3 mm of recession remained. The clinical attachment level changed from 3.5 Âą 1.3 mm to 1,8 ( Âą 0,7) mm during the observational time period. No statistically significant difference was found in the difference of probing depth. An increase in the width of gingiva was significant. With a baseline value of 1.5 Âą 0.9 mm an improvement of 2.4 Âą 0.8 mm after six month could be observed. 40 out of 62 recessions were considered a thin biotype at baseline. After 6 months all 62 sites were assessed thick. Conclusions: The results demonstrate the capacity of the bovine pericardium based non-cross linked collagen matrix for successful root coverage. This material was able to enhance gingival thickness and the width of keratinized gingiva. The percentage of root coverage achieved thereby is comparable to existing techniques. This method might contribute to an increase of patient's comfort and an enhanced aesthetical outcome

    Estimating the malaria risk of African mosquito movement by air travel

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    BACKGROUND: The expansion of global travel has resulted in the importation of African Anopheles mosquitoes, giving rise to cases of local malaria transmission. Here, cases of 'airport malaria' are used to quantify, using a combination of global climate and air traffic volume, where and when are the greatest risks of a Plasmodium falciparum-carrying mosquito being importated by air. This prioritises areas at risk of further airport malaria and possible importation or reemergence of the disease. METHODS: Monthly data on climate at the World's major airports were combined with air traffic information and African malaria seasonality maps to identify, month-by-month, those existing and future air routes at greatest risk of African malaria-carrying mosquito importation and temporary establishment. RESULTS: The location and timing of recorded airport malaria cases proved predictable using a combination of climate and air traffic data. Extending the analysis beyond the current air network architecture enabled identification of the airports and months with greatest climatic similarity to P. falciparum endemic regions of Africa within their principal transmission seasons, and therefore at risk should new aviation routes become operational. CONCLUSION: With the growth of long haul air travel from Africa, the identification of the seasonality and routes of mosquito importation is important in guiding effective aircraft disinsection and vector control. The recent and continued addition of air routes from Africa to more climatically similar regions than Europe will increase movement risks. The approach outlined here is capable of identifying when and where these risks are greatest

    Keeping the Faith: African American Faith Leaders’ Perspectives and Recommendations for Reducing Racial Disparities in HIV/AIDS Infection

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    In Philadelphia, 66% of new HIV infections are among African Americans and 2% of African Americans are living with HIV. The city of Philadelphia has among the largest numbers of faith institutions of any city in the country. Although faith-based institutions play an important role in the African American community, their response to the AIDS epidemic has historically been lacking. We convened 38 of Philadelphia’s most influential African American faith leaders for in-depth interviews and focus groups examining the role of faith-based institutions in HIV prevention. Participants were asked to comment on barriers to engaging faith-based leaders in HIV prevention and were asked to provide normative recommendations for how African American faith institutions can enhance HIV/AIDS prevention and reduce racial disparities in HIV infection. Many faith leaders cited lack of knowledge about Philadelphia’s racial disparities in HIV infection as a common reason for not previously engaging in HIV programs; others noted their congregations’ existing HIV prevention and outreach programs and shared lessons learned. Barriers to engaging the faith community in HIV prevention included: concerns about tacitly endorsing extramarital sex by promoting condom use, lack of educational information appropriate for a faith-based audience, and fear of losing congregants and revenue as a result of discussing human sexuality and HIV/AIDS from the pulpit. However, many leaders expressed a moral imperative to respond to the AIDS epidemic, and believed clergy should play a greater role in HIV prevention. Many participants noted that controversy surrounding homosexuality has historically divided the faith community and prohibited an appropriate response to the epidemic; many expressed interest in balancing traditional theology with practical public health approaches to HIV prevention. Leaders suggested the faith community should: promote HIV testing, including during or after worship services and in clinical settings; integrate HIV/AIDS topics into health messaging and sermons; couch HIV/AIDS in social justice, human rights and public health language rather than in sexual risk behavior terms; embrace diverse approaches to HIV prevention in their houses of worship; conduct community outreach and host educational sessions for youth; and collaborate on a citywide, interfaith HIV testing and prevention campaign to combat stigma and raise awareness about the African American epidemic. Many African American faith-based leaders are poised to address racial disparities in HIV infection. HIV prevention campaigns should integrate leaders’ recommendations for tailoring HIV prevention for a faith-based audience
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