20,786 research outputs found

    Short-term performance variations of different photovoltaic system technologies under the humid subtropical climate of Kanpur in India

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    The study discusses the short-term performance variations of grid-connected photovoltaic (PV) systems installed in Kanpur, India. The analysis presents a holistic view of the performance variations of three PV array technologies [multi-crystalline (multi-Si), copper indium gallium diselenide and amorphous silicon] and two inverter types (high-frequency transformer and low-frequency transformer). The analysis considers the DC–AC conversion efficiency of the inverter, system performance through performance ratio (PR) calculations, energy variations between fixed and tracking systems and the comparison between calculated and simulated data for the examined period. The energy output difference between the tracking and fixed systems of the same PV technology show that these are dependent on differences in temperature coefficient, shading and other system related issues. The PR analysis shows the effect of temperature on the multi-Si system. The difference between the simulated and measured values of the systems was mostly attributed to the irradiance differences. Regarding the inverter evaluation, the results showed that both inverter types underperformed in terms of the conversion efficiency compared with nameplate values

    Preterm gut microbiota and metabolome following discharge from intensive care

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    The development of the preterm gut microbiome is important for immediate and longer-term health following birth. We aimed to determine if modifications to the preterm gut on the neonatal intensive care unit (NICU) impacted the gut microbiota and metabolome long-term. Stool samples were collected from 29 infants ages 1–3 years post discharge (PD) from a single NICU. Additional NICU samples were included from 14/29 infants. Being diagnosed with disease or receiving increased antibiotics while on the NICU did not significantly impact the microbiome PD. Significant decreases in common NICU organisms including K. oxytoca and E. faecalis and increases in common adult organisms including Akkermansia sp., Blautia sp., and Bacteroides sp. and significantly different Shannon diversity was shown between NICU and PD samples. The metabolome increased in complexity, but while PD samples had unique bacterial profiles we observed comparable metabolomic profiles. The preterm gut microbiome is able to develop complexity comparable to healthy term infants despite limited environmental exposures, high levels of antibiotic administration, and of the presence of serious disease. Further work is needed to establish the direct effect of weaning as a key event in promoting future gut health

    An experimental investigation of the combustion performance of human faeces

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    Poor sanitation is one of the major hindrances to the global sustainable development goals. The Reinvent the Toilet Challenge of the Bill and Melinda Gates Foundation is set to develop affordable, next-generation sanitary systems that can ensure safe treatment and wide accessibility without compromise on sustainable use of natural resources and the environment. Energy recovery from human excreta is likely to be a cornerstone of future sustainable sanitary systems. Faeces combustion was investigated using a bench-scale downdraft combustor test rig, alongside with wood biomass and simulant faeces. Parameters such as air flow rate, fuel pellet size, bed height, and fuel ignition mode were varied to establish the combustion operating range of the test rig and the optimum conditions for converting the faecal biomass to energy. The experimental results show that the dry human faeces had a higher energy content (∼25 MJ/kg) than wood biomass. At equivalence ratio between 0.86 and 1.12, the combustion temperature and fuel burn rate ranged from 431 to 558 °C and 1.53 to 2.30 g/min respectively. Preliminary results for the simulant faeces show that a minimum combustion bed temperature of 600 ± 10 °C can handle faeces up to 60 wt.% moisture at optimum air-to-fuel ratio. Further investigation is required to establish the appropriate trade-off limits for drying and energy recovery, considering different stool types, moisture content and drying characteristics. This is important for the design and further development of a self-sustained energy conversion and recovery systems for the NMT and similar sanitary solutions

    Transmitochondrial embryonic stem cells containing pathogenic mtDNA mutations are compromised in neuronal differentiation

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    Objectives:  Defects of the mitochondrial genome (mtDNA) cause a series of rare, mainly neurological disorders. In addition, they have been implicated in more common forms of movement disorders, dementia and the ageing process. In order to try to model neuronal dysfunction associated with mitochondrial disease, we have attempted to establish a series of transmitochondrial mouse embryonic stem cells harbouring pathogenic mtDNA mutations. Materials and methods: Transmitochondrial embryonic stem cell cybrids were generated by fusion of cytoplasts carrying a variety of mtDNA mutations, into embryonic stem cells that had been pretreated with rhodamine 6G, to prevent transmission of endogenous mtDNA. Cybrids were differentiated into neurons and assessed for efficiency of differentiation and electrophysiological function. Results:  Neuronal differentiation could occur, as indicated by expression of neuronal markers. Differentiation was impaired in embryonic stem cells carrying mtDNA mutations that caused severe biochemical deficiency. Electrophysiological tests showed evidence of synaptic activity in differentiated neurons carrying non-pathogenic mtDNA mutations or in those that caused a mild defect of respiratory activity. Again, however, neurons carrying mtDNA mutations that resulted in severe biochemical deficiency had marked reduction in post-synaptic events. Conclusions:  Differentiated neurons carrying severely pathogenic mtDNA defects can provide a useful model for understanding how such mutations can cause neuronal dysfunction

    The environmental impact of nutrition transition in three case study countries

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    Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.Peer reviewedPublisher PD

    Individual leader to interdependent leadership: A case study in leadership development and tripartite evaluation

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    This article is available open access through the publisher’s website at the link below. Copyright @ 2013 Sage Publications.The Problem - In this case study we see a move away from orthodox views of school leadership as “headship” to a more contemporary model of educational leadership wherein we note a departure from functional, curricula-based school leadership toward more human resource development (HRD) approaches. The aim of this study was to consider the effectiveness of an educational development program for middle leaders within an educational establishment. The Solution - We examined the impact of a bespoke higher education leadership development intervention in Leadership (and Change) on the formation and cohesiveness of a newly formed innovative leadership structure. The Stakeholders - The leadership development intervention was designed through a tripartite collaboration including a university, senior school leaders, and staff. The intervention was designed to shift leadership from individual leader agency to interdependent human leadership agency. Through tripartite evaluation we uncover leadership development praxis that transcends the boundaries of conventional educational leadership and reemphasizes the benefits of bridging the academic/practitioner divide and the application of theory to praxis

    “True fan = watch match”? In Search of the ‘Authentic’ Soccer Fan.

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    Academics have created typologies to divide association football (soccer) fans into categories based upon the assumed ‘authenticity’ of their fandom practices. One of the main requirements of ‘authentic’ fandom has been assumed to be match attendance. The goal of this paper was to critically assess this assumption through considering how fans themselves talk about the significance of match attendance as evidence of ‘authentic’ fandom. In light of the fact that the voices of English non-league fans on the ‘authenticity’ debate have so far been overshadowed by the overbearing focus of much previous research on the upper echelons of English soccer, an e-survey was conducted with 151 members of an online community of fans of English Northern League (NL) clubs (a semi-professional / amateur league based in North East England). Findings revealed that opinion was divided on the constituents of ‘authentic’ fandom and match attendance was not deemed to be the core evidence of support for a club by 42% of the sample. Elias (1978) suggested that dichotomous thinking hinders sociological understanding and it is concluded that fan typologies are not sufficient for assessing the ‘authenticity’ of fan activities

    Review of creep deformation and rupture mechanism of P91 alloy for the development of creep damage constitutive equations under low stress level

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    This paper presents a review of creep deformation and rupture mechanism of P91 alloy for the development of its creep damage constitutive equations under lower stress level. Creep damage is one of the serious problems for the high temperature industries and computational approach (such as continuum damage mechanics) has been developed and used, complementary to the experimental approach, to assist safe operation. However, there are no ready creep damage constitutive equations to be used for prediction the lifetime for this type of alloy, partially under low stress. The paper reports a critical review on the deformation and damage evolution characteristics of this alloy, particularly under low stress, to form the physical base for the development of creep damage constitutive equations. It covers the influence of the stress level, states of stress, and the failure criterion

    Evaluating sustainability in the UK fast food supply chain: Dimensions, Awareness and Practice

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    Purpose - This paper investigates the level of concern and practice of sustainable management in the fast food supply chain in the North of England, targeting a business population with cultural, social and economic diversity. Methodology – A questionnaire using Likert Scoring recorded variations in current practice and attitudes towards sustainable business. A two-stage Cluster Analysis was conducted to analyse the multi-attribute ordinal data obtained from the questionnaire. Findings - Significant differences were found among clusters of Fast food businesses in terms of their sustainability concern and practice, which is of interest to policy makers, consumers and supply chain partners. Medium-sized fast food dealers emerge with high environmental and social concern, but poor practice; larger retailers and fast food chains appear to have both fair social and environmental awareness and practice; and there is a cluster of small takeaway-specific outlets that have particularly low levels of knowledge of sustainability or sustainable practices. Market failure is prevalent amongst these businesses and without regulation this represents a possible threat to the sector. Research limitations – Reliance on stated rather than revealed preferences and the regional focus of the study may limit the implications of this analysis but it is a major step forward in understanding what has in the past been a very difficult sector to investigate due to data paucity. Practical implications - Fast food is a sector with a lack of transparency which has attracted little academic attention to date, due to the difficulties of empirical analysis rather than lack of interest in a key food consumption sector. The message for the sector is to monitor its act, across all business types or face regulatory and policy intervention. Originality - The research conducts a three-dimensional sustainability analysis of fast food supply chains to investigate the differences and trade-offs between different sustainability dimensions
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