370 research outputs found

    Flat growth of 7075, 7475, 7050 and 7049 aluminum alloy plate in stress corrosion environments: 2-year marine atmosphere results

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    Marine atmospheric exposure of smooth and precracked specimens from 7075, 7475, 7050 and 7049 plates support the conclusion that for a given strength level, the short transverse stress corrosion resistance of 7050-T7X and 7049-T7X is superior to that of 7075-T7X. The threshold stress intensity (K sub Iscc) for these alloys is about 25 MPa square root m at a yield strength of about 460 MPa; the corresponding yield strength level for 7075-T7X at this SCR level is about 425 MPa. Additional tests on two lots of high-toughness 7475 plate indicate that this alloy is capable of achieving K sub Iscc values of about 35 MPa square root m at yield strengths of 400-450 MPa. Precracked specimens from all these 7XXX-series alloys are subject to self loading from corrosion product wedging. This effect causes stress corrosion cracks to continue growing at very low apparent stress intensities, and should therefore be considered a potential driving force for stress corrosion in design and materials selection

    Flaw growth of 7075, 7475, 7050 and 7049 aluminum alloy plate in stress corrosion environments: 4-year marine atmosphere results

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    After nearly 53 months of exposure to marine atmosphere, crack growth in SL DCB specimens from 7075, 7475, 7050, and 7049-T7X plate has slowed to the arbitrary 10 to the -10 power m/sec used to define threshold stress intensity. Because some specimens appear to be approaching crack arrest, the importance of self-loading from corrosion product wedging as a significant driving force for crack propagation in overaged materials is questioned. Crack length-time data were analyzed using a computer curve fitting program which minimized the effects of normal data scatter, and provided a clearer picture of material performance. Precracked specimen data are supported by the results of smooth specimen tests. Transgranular stress corrosion cracking was observed in TL DCB specimens from all four alloys. This process is extremely slow and is characterized by a striated surface morphology

    Flaw growth of 7075, 7475, 7050 and 7049 aluminum alloy plate in stress corrosion environments

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    Marine atmosphere and laboratory stress corrosion test results on smooth and precracked specimens from 7075, 7475, 7050, and 7049 alloy plates (1.25 and 3.0-in. thick) are presented. It is shown that for a given strength level, alloys 7050-T7X and 7049-T7X have superior short-transverse stress corrosion resistance (SCR) to 7X75-T7X. At typical strength levels above the minimum, for example, SCR of these alloys is considerably better than that of 7075-T76, and approaches that of 7075-T73. Alloy 7475 maintains an advantage in the area of fracture toughness, however, because it can be thermally processed to give particularly clean microstructures. Results from precracked specimens are in good qualitative agreement with those obtained from smooth specimens. Although both specimen types are capable of distinguishing between -T6, -T76 and -T73 tempers in relatively short time periods the precracked specimen provides more information about crack growth rates

    Mobile applications for weather and climate information: their use and potential for smallholder farmers

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    Mobile phones are increasingly being used to provide smallholder farmers with agricultural and related information. There is currently great interest in their scope to communicate climate and weather information. Farmers consistently identify demand for weather information and whilst ICTs may be one way of delivering this at scale there are concerns that this should not be seen as a panacea. At a time when there have been a range of initiatives and projects that have been implemented this paper seeks to draw lessons and identify key considerations to inform the development of future mobile applications to provide climate services to smallholder farmers. A literature review, interviews with key informants and experts and 15 case study reviews were conducted. This focused principally on Sub Saharan Africa but included some examples from India. Despite numerous initiatives few have developed fully beyond the pilot stage and few have been evaluated. Some of the provision to date has been of questionable value to farmers. A key observation is that relatively little attention has been paid in design, to the needs for and use of both the information and technology by farmers, and few attempts made to differentiate provision according to gender and other demographic variables. Other factors contributing to success included communications approaches, which are interactive and/or involve trusted intermediaries who can add context to and help interpret more complex information. Providing weather information alongside other services as ‘bundles’ and in conjunction with complementary communications approaches appears to work well. An important challenge is how to meet farmers’ needs for location specific, timely and relevant information in economically sustainable ways. More widely there are challenges in achieving successful business models and potential conflicts between initiatives driven by mobile network operators and public goals. The study identified areas of considerable potential which include: the use of increasingly available mobile data connections to ensure locally relevant content is available to farmers in timely fashion (including both historical climate information and forecasts); development of participatory decision making tools to enable farmers to interpret information for their own contexts and consider implications and management options; use of visual applications and participatory video on mobile devices to enhance learning and advisory services for farmers; the potential for increased feedback between farmers and service providers as well as increased knowledge sharing between farmers provided by the use of social media

    Downregulation of Mcl-1 has anti-inflammatory pro-resolution effects and enhances bacterial clearance from the lung

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    Phagocytes not only coordinate acute inflammation and host defense at mucosal sites, but also contribute to tissue damage. Respiratory infection causes a globally significant disease burden and frequently progresses to acute respiratory distress syndrome, a devastating inflammatory condition characterized by neutrophil recruitment and accumulation of protein-rich edema fluid causing impaired lung function. We hypothesized that targeting the intracellular protein myeloid cell leukemia 1 (Mcl-1) by a cyclin-dependent kinase inhibitor (AT7519) or a flavone (wogonin) would accelerate neutrophil apoptosis and resolution of established inflammation, but without detriment to bacterial clearance. Mcl-1 loss induced human neutrophil apoptosis, but did not induce macrophage apoptosis nor impair phagocytosis of apoptotic neutrophils. Neutrophil-dominant inflammation was modelled in mice by either endotoxin or bacteria (Escherichia coli). Downregulating inflammatory cell Mcl-1 had anti-inflammatory, pro-resolution effects, shortening the resolution interval (R(i)) from 19 to 7 h and improved organ dysfunction with enhanced alveolar–capillary barrier integrity. Conversely, attenuating drug-induced Mcl-1 downregulation inhibited neutrophil apoptosis and delayed resolution of endotoxin-mediated lung inflammation. Importantly, manipulating lung inflammatory cell Mcl-1 also accelerated resolution of bacterial infection (R(i); 50 to 16 h) concurrent with enhanced bacterial clearance. Therefore, manipulating inflammatory cell Mcl-1 accelerates inflammation resolution without detriment to host defense against bacteria, and represents a target for treating infection-associated inflammation

    Roads to interdisciplinarity - working at the nexus among food systems, nutrition and health: 1st annual Agriculture, Nutrition and Health (ANH) Academy Week, Addis Ababa (Ethiopia), 20-24 June 2016

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    The development agenda over the next 15 years will be framed by the Sustainable Development Goals (SDGs), of which more than half relate either directly or indirectly to the agricultural sector, highlighting its importance in economic growth and development of low- and middle-income countries (LMICs) (FAO 2015). It is therefore imperative that agricultural systems are better understood, so that they may be strengthened and optimised to deliver outcomes in line with the SDGs. The interface between agriculture, nutrition and health is particularly multifaceted and complex, and the development of successful strategies will require an integrated and multi-sectoral approach (Dorward and Dangour 2012; Jones and Ejeta 2016). ‘Agri-health’ is an evolving paradigm seeking to unify research approaches and methodologies between agriculture and health. Research within the field encapsulates a broad range of disciplines, locations and actors, and aligns these into a common research agenda. In doing so, agri-health aims to transcend barriers imposed by the longstanding institutional and disciplinary silos. Much progress has been made in recent years in this regard (Harris et al. 2013; Kanter et al. 2014; Picchioni et al. 2015). However, more coordinated efforts are required to generate consensus and target strategic priorities amongst the many existing information gaps (Webb and Kennedy 2014). Understanding the linkages between complex issues such as globalisation, climate change, food systems, and evolving burdens of malnutrition is central to agri-health research. The Leverhulme Centre for Integrative Research on Agriculture and Health (LCIRAH) was created in 2010 with a key focus on agri-health interdisciplinary research. LCIRAH includes experts from across the member colleges of the University of London: the London School of Hygiene and Tropical Medicine (LSHTM), the School of Oriental and African Studies (SOAS), and the Royal Veterinary College (RVC). The Agriculture, Nutrition and Health Academy (ANH Academy), was established in 2015 as a platform to facilitate learning, knowledge sharing, capacity building and collaborative partnerships among the growing global community of researchers, practitioners and policy makers working within agri-health. It was developed with support from the Innovative Metrics and Methods for Agriculture and Nutrition Actions (IMMANA) research programme,Footnote1 led by LCIRAH and Tufts University, in partnership with the CGIAR Programme on Agriculture for Nutrition and Health (A4NH). Within this scope, the ANH Academy hosts an annual ANH Academy Week, building on the legacy of five agri-health research conferences organised by LCIRAH; as well as events and activities coordinated under the CGIAR A4NH. The inaugural ANH Academy Week took place in Addis Ababa, Ethiopia, in June 2016 and included two days of interactive ‘learning labs’ (training sessions on skills and methods across a broad range of disciplines in agri-health), followed by a three-day research conference. The conference included a mix of abstract-driven sessions, round table discussions, and keynote speeches from across the spectrum of agriculture, nutrition and health disciplines, and a wide range of countries. Hawkes et al. (2012) developed a conceptual framework (Fig. 2, hereafter referred to as the Framework), outlining the key pathways through which agriculture may affect nutritional status in Low and Middle Income Countries (LMICs), as well as broader drivers of these pathways. Drawing on this Framework, this paper aims to provide an analytical synthesis of the ANH Academy week by mapping the research and debates presented during the conference

    Livelihood responses to Lantana camara invasion and biodiversity change in southern India: application of an asset function framework

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    Natural resources play key roles as assets in the livelihoods of rural communities. However, the benefits of these assets in livelihoods are frequently conceived narrowly as income generating or vulnerability reducing. We contend that they have other important roles to play in poverty reduction and livelihood change. In this paper we use a case study of two ethnic communities in a village in southern India to investigate livelihood responses to change in forest biodiversity through an examination of changes in attributes of natural assets resulting from the invasion of Lantana camara and wider socio-economic change. The invasion of forest by Lantana has contributed to changes in the attributes and functions of four key natural assets: forest grazing, bamboo for basketry, Phoenix loureie for brooms, and wild yams. We observe that differences in households’ and individuals’ ability to substitute important functions of lost or declining assets affect their ability to adapt to changes in resource availability and attributes. Analysing changes in asset attributes for different user groups allows the social effects of environmental change to be disaggregated

    Urine tenofovir and dried blood spot tenofovir diphosphate concentrations and viraemia in people taking efavirenz and dolutegravir based antiretroviral therapy

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    Objective: We aimed to determine whether urine tenofovir (TFV) and dried blood spot (DBS) tenofovir diphosphate (TFV-DP) concentrations are associated with concurrent HIV viraemia. Design: Cross-sectional study among people with HIV (PWH) receiving tenofovir disoproxil fumarate (TDF)-based antiretroviral therapy (ART). Methods: We used dual tandem liquid chromatography and mass spectrometry to measure urine TFV and DBS TFV-DP concentrations, and evaluated their associations with concurrent viraemia ≥1000 copies/mL using logistic regression models. In exploratory analyses, we used receiver operating curves to estimate optimal urine TFV and DBS TFV-DP thresholds to predict concurrent viraemia. Results: Among 124 participants, 68 (54.8%) were women, median age was 39 years (interquartile range [IQR] 34–45) and 74 (59.7%) were receiving efavirenz versus 50 (40.3%) receiving dolutegravir. Higher concentrations of urine TFV (1000 ng/mL increase, odds ratio [OR] 0.97 95%CI 0.94–0.99, p = 0.005) and DBS TFV-DP (100 fmol/punch increase, OR 0.76, 95%CI 0.67–0.86, p < 0.001) were associated with lower odds of viraemia. There was evidence that these associations were stronger among people receiving dolutegravir than among people receiving efavirenz (urine TFV p = 0.072, DBS TFV-DP p = 0.003). Nagelkerke Pseudo-R2 for the DBS TFV-DP models was higher than for the urine TFV models, demonstrating a stronger relationship between DBS TFV-DP and viraemia. Among people receiving dolutegravir, a DBS TFV-DP concentration of 483 fmol/punch had 88% sensitivity and 85% specificity to predict concurrent viraemia ≥1000 copies/ml. Conclusions: Among PWH receiving TDF-based ART, urine TFV concentrations, and in particular DBS TFV-DP concentrations, were strongly associated with concurrent viraemia, especially among people receiving dolutegravir
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