445 research outputs found

    The EDEM methodology for housing upgrade analysis, carbon and energy labelling and national policy development

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    The ESRU Domestic Energy Model (EDEM) has been developed in response to demand from policy makers for a tool to assist in analysis of options for improving carbon and energy performance of housing across a range of possible future technologies, behaviours and environmental factors. A major challenge is to comprehend the large variation in fabric, systems (heating, hot water, lighting and appliances) and behaviours across the housing stock as well as uncertainty over future trends. Existing static models have limited ability to represent dynamic behaviour while use of detailed simulation has been based on modelling only a small number of representative designs. To address these challenges, EDEM has been developed as an easy to use, Web based tool, built on detailed simulation models aligned with national house survey data. From pragmatic inputs, EDEM can determine energy use and carbon emissions at any scale, from individual dwelling to national housing stock. EDEM was used at the behest of the Scottish Building Standards Agency and South Ayrshire Council to quantify the impact of upgrades including new and renewable energy systems. EDEM was also used to rate energy/carbon performance of dwellings as required by the EU Directive (EU, 2002). This paper describes the evolving EDEM methodology, its structure and operation then presents findings from applications. While initial EDEM projects have been for the Scottish housing stock the methodology is structured to facilitate project development and application to other countries

    Considering the impact of situation-specific motivations and constraints in the design of naturally ventilated and hybrid buildings

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    A simple logical model of the interaction between a building and its occupants is presented based on the principle that if free to do so, people will adjust their posture, clothing or available building controls (windows, blinds, doors, fans, and thermostats) with the aim of achieving or restoring comfort and reducing discomfort. These adjustments are related to building design in two ways: first the freedom to adjust depends on the availability and ease-of-use of control options; second the use of controls affects building comfort and energy performance. Hence it is essential that these interactions are considered in the design process. The model captures occupant use of controls in response to thermal stimuli (too warm, too cold etc.) and non-thermal stimuli (e.g. desire for fresh air). The situation-specific motivations and constraints on control use are represented through trigger temperatures at which control actions occur, motivations are included as negative constraints and incorporated into a single constraint value describing the specifics of each situation. The values of constraints are quantified for a range of existing buildings in Europe and Pakistan. The integration of the model within a design flow is proposed and the impact of different levels of constraints demonstrated. It is proposed that to minimise energy use and maximise comfort in naturally ventilated and hybrid buildings the designer should take the following steps: 1. Provide unconstrained low energy adaptive control options where possible, 2. Avoid problems with indoor air quality which provide motivations for excessive ventilation rates, 3. Incorporate situation-specific adaptive behaviour of occupants in design simulations, 4. Analyse the robustness of designs against variations in patterns of use and climate, and 5. Incorporate appropriate comfort standards into the operational building controls (e.g. BEMS)

    The prebiotic effects of biscuits containing partially hydrolysed guar gum and fructo-oligosaccharides - a human volunteer study

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    Prebiotics are non-digestible food ingredients that target selected groups of the human colonic microflora, thus having the ability to alter the composition towards a more ‘beneficial' community, i.e. selectively increasing populations of bifidobacteria and/or lactobacilli. In the present study the prebiotic potential of partially hydrolysed guar gum (PHGG) and fructo-oligosaccharides (FOS) in a biscuit was assessed in human volunteers. Fluorescent in situ hybridization using oligonucleotide probes targeting Bacteroides spp., Bifidobacterium spp., Clostridium spp. and Lactobacillus-Enterococcus spp. were used for the bacteriology and total bacteria were enumerated using the fluorescent stain 4′,6-diamidino-2-phenylindole. Thirty-one volunteers consumed daily either three experimental biscuits (providing a total (g/d) of 6·6 FOS and 3·4 PHGG) or three placebo biscuits for two 21-d crossover periods. Bifidobacteria significantly increased in number on ingestion of the experimental biscuits compared with pre-treatment and placebo population levels. Bifidobacterial numbers returned to pretreatment levels within 7 d of the cessation of intake of experimental biscuits. A correlation was observed between the initial faecal bifidobacterial numbers and the magnitude of bifidogenesis, with volunteers who possessed low initial population levels of bifidobacteria experiencing the greatest increase in bifidogenesis. No changes were observed in the other bacterial groups monitored during the trial. Thus, the prebiotic nature of FOS and PHGG was maintained in a final food product as evidenced from the selective increase in bifidobacterial number

    Functional redundancy in microbial ecosystems

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    A healthy ecosystem is generally characterized by the stable performance of essential ecological functions, which are typically supported redundantly by multiple species. Although the concept of functional redundancy is well-established in macroecology, estimating redundancy in microbial communities remains challenging and has thus been only partially explored. In this study, we aim to quantify the redundancy within the complex community of microorganisms in the gastrointestinal tract to predict the risk of functional loss in the human gut microbiome, thereby assessing the potential risk of dysbiosis. We specified a diversity-based redundancy index and applied it to metagenomics samples from obese patients before and after bariatrics surgery. We observed a general increase in functional redundancy 12 months after bariatric surgery for nearly all functions showing significant differences. Our findings support the assumption that a high level of redundancy is typically associated with a healthier microbiome, thereby highlighting the importance of functional redundancy as a key biodiversity metric for microbiome stability and resilience

    Energy and indoor environmental performance of typical Egyptian offices : survey, baseline model and uncertainties

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    Egyptian electricity demands have increased in recent years and are projected to grow further with significant economic and social impacts. Recently, mandatory and voluntary building codes based on international standards have been increasingly adopted. The performance of existing Egyptian buildings is not well understood making the impact of these new codes uncertain. This paper aims to provide insights into existing Egyptian building performance, and elaborate a process for developing a representative model to assist in future policy. The work presented is for office buildings but intended to be widely replicable. An energy survey was carried out for 59 Egyptian offices, categorised by building service type, it was observed that energy use increases as building services increase, and existing Egyptian offices use less energy than benchmarks. A more detailed investigation for a case study office was carried out, to inform detailed model calibration. This provided insight into energy use, thermal comfort and environmental conditions, and revealed high variability in behaviours. A calibrated model was created for the case study office, then a baseline model and input parameter sets created to represent generalised performance. Future uses including assessment of the impact of codes are discussed, and further replication potentials highlighted

    In vitro faecal fermentation of Tritordeum breads and its effect on the human gut health

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    Spontaneous fermentation of Tritordeum flour enhances the nutritional potential of this hybrid cereal. However, the effect of consumption of Tritordeum sourdough bread (SDB) on gut health remains to be elucidated. This study investigated the effect of in vitro digestion and faecal fermentation of SDB compared to that of traditional baker's yeast (BYB) Tritordeum bread. After 24-h anaerobic faecal fermentation, both SDB and BYB (1% w/v) induced an increase in the relative abundances of Bifidobacterium, Megasphaera, Mitsuokella, and Phascolarctobacterium genera compared to baseline, while concentrations of acetate and butyrate were significantly higher at 24 h for SDB compared to those for BYB. Integrity of intestinal epithelium, as assessed through in vitro trans-epithelial electrical resistance (TEER) assay, was slightly increased after incubation with SDB fermentation supernatants, but not after incubation with BYB fermentation supernatants. The SDB stimulated in vitro mucosal immune response by inducing early secretion of inflammatory cytokines, IL-6 and TNF-α, followed by downregulation of the inflammatory trigger through induction of anti-inflammatory IL-10 expression. Overall, our findings suggest that Tritordeum sourdough can modulate gut microbiota fermentation activity and positively impact the gut health

    An experimental in-vivo canine model for adult shunt infection

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    <p>Abstract</p> <p>Background</p> <p>Detailed human studies of the mechanisms and development of shunt infection in real time are not possible, and we have developed a canine hydrocephalus model to overcome this. The intention of this pilot study was to show that the canine hydrocephalus model could be shunted using conventional "human" shunts, and that a shunt infection could be established so that further studies could then be planned.</p> <p>Methods</p> <p>Hydrocephalus was induced in seven dogs (<it>Canis familiaris</it>) by fourth ventricle obstruction. Four weeks later they were shunted using a Hakim Precision valve. Four of the dogs received shunts whose ventricular catheter had been inoculated with <it>Staphylococcus epidermidis</it>, and three were uninoculated controls. Four weeks after shunting the dogs were sacrificed and necropsy was performed. Removed shunts and tissue samples were examined microbiologically and isolates were subjected to detailed identification and genomic comparison.</p> <p>Results</p> <p>All the dogs remained well after shunting. Examination of removed shunt components revealed <it>S. epidermidis </it>in the brain and throughout the shunt system in the four inoculated animals, but in two of these <it>Staphylococcus intermedius </it>was also found. <it>S. intermedius </it>was also isolated from all three "negative" controls. There were slight differences between <it>S. intermedius </it>strains suggesting endogenous infection rather than cross- infection from a point source.</p> <p>Conclusion</p> <p>Shunt infection was established in the canine model, and had the experiment been extended beyond four weeks the typical microbiological, pathological and clinical features might have appeared. The occurrence of unplanned shunt infections in control animals due to canine normal skin flora reflects human clinical experience and underlines the usual source of bacteria causing shunt infection.</p

    The energy and indoor environmental performance of Egyptian offices : parameter analysis and future policy

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    Buildings are a significant contributor to the rapidly increasing electricity demand in Egypt which is straining the existing supply network causing economic and social impacts. There are current initiatives aimed at improved building performance including adoption of international standards. The performance of existing Egyptian buildings is not well understood making the impact of these international standards uncertain. This paper provides insight into performance of current Egyptian office buildings through a multi-building energy survey and a detailed case study. The most common office type in the survey has natural ventilation and local cooling. A process to capture observed performance in a representative model and input parameter set is presented. The model is used to investigate performance impacts of parameters including: location, weather, building envelope, intensity of occupancy, behaviour, and installed systems including the HVAC strategy. HVAC strategy was identified as the most significant factor. Typical Egyptian offices with natural ventilation and local cooling systems under personal control have electricity demand less than 50% of centrally serviced buildings. System efficiencies (HVAC, lights, equipment) and occupant behaviour (e.g. use of systems, temperatures) were also identified as significant factors, each with potential of around 30% saving compared to current typical offices. Possible policy measures to promote energy efficient systems and energy conscious behaviour are proposed which together can reduce the energy demand of typical offices by 50%. Trade-offs between energy use and indoor environmental quality (IEQ) are discussed

    Nutrition challenges ahead

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    The breakout session ‘Nutrition challenges ahead’ was held at the EFSA 2nd Scientific Conference ‘Shaping the Future of Food Safety, Together’ (Milan, Italy, 14–16 October 2015) to address the main problems in the area of nutrition to be faced in the 21st Century, both at a global and individual level. The nutrition challenges ahead are diverse and depend on agricultural, socioeconomic and individual factors. At a global level, food security, food sustainability and decreasing the impact of food production on climate change are of paramount importance. Decreasing the prevalence of obesity and related disorders, which may coexist with selected micronutrient deficiencies, is a major challenge for wealthy countries; for developing countries and rural food systems, fighting protein–energy malnutrition and micronutrient deficiencies is a priority. Diets based on a wide variety of nutrient-rich local plant foods (e.g. fruits, vegetables, whole grain cereals, vegetable oils, nuts) that contain moderate amounts of animal protein (preferably in the form of fish) and are low in saturated and trans-fatty acids, added sugars and sodium, are healthy, nutritious, sustainable and climate friendly. Creating an environment where such diets are also economically advantageous and convenient may be a part of a global solution to these nutritional challenges. Individuals, however, are unique regarding their genetic background, gut microbiota and health status. In addition, nutrition may already play a role in the development (and prevention) of disease very early in life. Thus, additional health benefits could be achieved by tailoring nutritional strategies to particular population subgroups or even individuals on the basis of current and future knowledge about the relationship between nutrients, genes, the microbiome and health. New technologies and food innovation may help in finding novel foods fit for purpose
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