2,841 research outputs found

    Currnent and likely future performance of advanced natural ventilation

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    Advanced natural ventilation (ANV), often characterised by the use of dedicated ventilation stacks, shafts and other architecture features such as atria, light wells, has gained popularity for natural ventilation design in recent decades. In this research, a prototype ANV system is proposed, and the likely thermal performance in a range of UK climatic conditions predicted using dynamic thermal simulation. The simulations showed that ANV has greater resilience to future climatic conditions in the north of the UK than in the south-east and that, for the assumed internal heat gains, the design studied is unlikely to maintain comfortable conditions in the southeast of England beyond the middle of this century

    Long-term increase in mesozooplankton biomass in the Sargasso Sea: Linkage to climate and implications for food web dynamics and biogeochemical cycling

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    Changes in zooplankton biomass and species composition over long time scales can have significant effects on biogeochemical cycling and transfer of energy to higher trophic levels. We analyzed size-fractionated mesozooplankton biomass (\u3e200 mu m) from biweekly to monthly day and night tows taken from 1994 to 2010 in the epipelagic zone at the Bermuda Atlantic Time series Study (BATS) site in the oligotrophic North Atlantic subtropical gyre. During this 17-year period total mesozooplankton biomass increased 61% overall, although a few short-term downturns occurred over the course of the time series. The overall increase was higher in the nighttime compared to daytime, resulting in an increase in calculated diel vertical migrator biomass. The largest seasonal increase in total biomass was in the late-winter to spring (February-April). Associated with the larger increase in late-winter/spring biomass was a shift in the timing of annual peak biomass during the latter half of the time series (from March/April to a distinct March peak for all size fractions combined, and April to March for the 2-5 mm size fractions). Zooplankton biomass was positively correlated with sea-surface temperature, water column stratification, and primary production, and negatively correlated with mean temperature between 300 and 600 m. Significant correlations exist between multidecadal climate indices-the North Atlantic Oscillation plus three different Pacific Ocean climate indices, and BATS zooplankton biomass, indicating connections between patterns in climate forcing and ecosystem response. Resultant changes in biogeochemical cycling include an increase in the magnitude of both active carbon flux by diel vertical migration and passive carbon flux of fecal pellets as components of the export flux. The most likely mechanism driving the zooplankton biomass increase is bottom-up control by smaller phytoplankton, which has also increased in biomass and production at BATS, translating up the microbial food web into mesozooplankton. Decreases in top-down control or expansion of the range of tropical species northward as a result of warming may also play a role

    A panel model for predicting the diversity of internal temperatures from English dwellings

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    Using panel methods, a model for predicting daily mean internal temperature demand across a heterogeneous domestic building stock is developed. The model offers an important link that connects building stock models to human behaviour. It represents the first time a panel model has been used to estimate the dynamics of internal temperature demand from the natural daily fluctuations of external temperature combined with important behavioural, socio-demographic and building efficiency variables. The model is able to predict internal temperatures across a heterogeneous building stock to within ~0.71°C at 95% confidence and explain 45% of the variance of internal temperature between dwellings. The model confirms hypothesis from sociology and psychology that habitual behaviours are important drivers of home energy consumption. In addition, the model offers the possibility to quantify take-back (direct rebound effect) owing to increased internal temperatures from the installation of energy efficiency measures. The presence of thermostats or thermostatic radiator valves (TRV) are shown to reduce average internal temperatures, however, the use of an automatic timer is statistically insignificant. The number of occupants, household income and occupant age are all important factors that explain a proportion of internal temperature demand. Households with children or retired occupants are shown to have higher average internal temperatures than households who do not. As expected, building typology, building age, roof insulation thickness, wall U-value and the proportion of double glazing all have positive and statistically significant effects on daily mean internal temperature. In summary, the model can be used as a tool to predict internal temperatures or for making statistical inferences. However, its primary contribution offers the ability to calibrate existing building stock models to account for behaviour and socio-demographic effects making it possible to back-out more accurate predictions of domestic energy demand

    Sustainable refurbishment solutions for high-rise residential buildings in subtropical areas

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    Conference Theme: Mass Customisation and Sustainability in HousingBuilding maintenance and refurbishment has become a particular concern in developed economies, as there are many old buildings in urban areas. While various refurbishment methods have been developed for the purpose of sustainable development, these refurbishment approaches are designed for specific climatic condition and building characteristic. Until now, there is not much suggestion on which sustainable refurbishment methods are more suitable for subtropical areas like Hong Kong. This paper aims to bridge this gap by developing a set of sustainable refurbishment methods applicable to high-rise residential buildings in Hong Kong. The research begins by a comprehensive literature review of the existing sustainable refurbishment methods. The results of literature review form the basis of a preliminary screening according to the local climate and buildings feature. Interviews with experienced industry experts are conducted in order to confirm the applicability of the proposed methods. Through the above studies, a list of sustainable refurbishment methods for subtropical regions as well as a set of principles for selecting refurbishment methods are identified. The results of this study should help owners and design team members identify sustainable refurbishment to maximise the chance of success.published_or_final_versio

    Picoheterotroph (Bacteria and Archaea) biomass distribution in the global ocean

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    We compiled a database of 39 766 data points consisting of flow cytometric and microscopical measurements of picoheterotroph abundance, including both Bacteria and Archaea. After gridding with 1° spacing, the database covers 1.3% of the ocean surface. There are data covering all ocean basins and depths except the Southern Hemisphere below 350m or from April until June. The average picoheterotroph biomass is 3.9 ± 3.6 µg Cl-1 with a 20-fold decrease between the surface and the deep sea. We estimate a total ocean inventory of about 1.3 × 1029 picoheterotroph cells. Surprisingly, the abundance in the coastal regions is the same as at the same depths in the open ocean. Using an average of published open ocean measurements for the conversion from abundance to carbon biomass of 9.1 fg cell-1, we calculate a picoheterotroph carbon inventory of about 1.2 Pg C. The main source of uncertainty in this inventory is the conversion factor from abundance to biomass. Picoheterotroph biomass is ? 2 times higher in the tropics than in the polar oceans

    The ethics of facial recognition technologies, surveillance and accountability in an age of Artificial Intelligence: a comparative analysis of USA, EU and UK regulatory frameworks

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    The rapid development of facial recognition technologies (FRT) has led to complex ethical choices in terms of balancing individual privacy rights versus delivering societal safety. Within this space, increasingly commonplace use of these technologies by law enforcement agencies has presented a particular lens for probing this complex landscape, its application, and the acceptable extent of citizen surveillance. This analysis focuses on the regulatory contexts and recent case law in the United States (USA), United Kingdom (UK), and European Union (EU) in terms of the use and misuse of FRT by law enforcement agencies. In the case of the USA, it is one of the main global regions in which the technology is being rapidly evolved, and yet, it has a patchwork of legislation with less emphasis on data protection and privacy. Within the context of the EU and the UK, there has been a critical focus on the development of accountability requirements particularly when considered in the context of the EU’s General Data Protection Regulation (GDPR) and the legal focus on Privacy by Design (PbD). However, globally, there is no standardised human rights framework and regulatory requirements that can be easily applied to FRT rollout. This article contains a discursive discussion considering the complexity of the ethical and regulatory dimensions at play in these spaces including considering data protection and human rights frameworks. It concludes that data protection impact assessments (DPIA) and human rights impact assessments together with greater transparency, regulation, audit and explanation of FRT use, and application in individual contexts would improve FRT deployments. In addition, it sets out ten critical questions which it suggests need to be answered for the successful development and deployment of FRT and AI more broadly. It is suggested that these should be answered by lawmakers, policy makers, AI developers, and adopters

    Evaluation of Supplemental Energy Source for Grazing Stocker Cattle

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    Thirty-six steers grazing smooth bromegrass pastures were used to evaluate the effects of a supplemental energy source on available forage, grazing gains, subsequent finishing gains, and carcass characteristics. Supplementation treatments evaluated were: no supplement, a supplement with starch as the primary source of energy, and a supplement with fat as the primary source of energy. Supplements were formulated to provide the same quantity of protein and energy per head daily. Supplementation with the starchbased or fat-based supplement during the grazing phase resulted in higher (P \u3c 0.05) grazing gains than feeding no supplement. Supplementation during the grazing phase had no effect (P \u3e 0.05) on finishing gain, feed intake, and feed:gain. Steers supplemented with the starch-based supplement had greater (P \u3c 0.05) final finishing live weight and greater (P \u3c 0.05) hot carcass weight than those that received no supplement

    Evaluation of Supplemental Energy Source for Grazing Stocker Cattle

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    A total of 108 steers grazing smooth bromegrass pastures were used to evaluate the effects of supplemental energy source on available forage, grazing gains, subsequent finishing gains, and carcass characteristics in 2014, 2015, and 2016. Supplementation treatments evaluated were: no supplement, a supplement with starch as the primary source of energy, and a supplement with fat as the primary source of energy. Supplements were formulated to provide the same quantity of protein and energy per head daily. Supplementation with the starch-based or fat-based supplement during the grazing phase resulted in higher (P \u3c 0.05) grazing gains than feeding no supplement during all three years. In 2014 and 2016, grazing gains of steers supplemented with the starch-based or fat-based supplement were similar (P \u3e 0.05). In 2015, steers supplemented with the fat-based supplement had greater (P \u3c 0.05) grazing gains than those that received the starch-based supplement. In 2014, supplementation during the grazing phase had no effect (P \u3e 0.05) on finishing gain, feed intake, and feed:gain. Steers supplemented with the starch-based supplement had greater (P \u3c 0.05) final finishing liveweight, and greater (P \u3c 0.05) hot carcass weight than those that received no supplement. In 2015, steers fed the fat-based supplement had higher (P \u3c 0.05) final finishing liveweight, greater (P \u3c 0.05) hot carcass weight, and lower (P \u3c 0.05) finishing gain than those supplemented with the starch-based supplement or fed no supplement

    Evaluation of Supplemental Energy Source for Grazing Stocker Cattle

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    Seventy-two steers grazing smooth bromegrass pastures were used to evaluate the effects of supplemental energy source on available forage, grazing gains, subsequent finishing gains, and carcass characteristics in 2014 and 2015. Supplementation treatments evaluated were: no supplement, a supplement with starch as the primary source of energy, and a supplement with fat as the primary source of energy. Supplements were formulated to provide the same quantity of protein and energy per head daily. Supplementation with the starch-based or fat-based supplement during the grazing phase resulted in higher (P \u3c 0.05) grazing gains than feeding no supplement during both years. In 2015, steers supplemented with the fat-based supplement had greater (P \u3c 0.05) grazing gains than those that received the starch-based supplement. In 2014, supplementation during the grazing phase had no effect (P \u3e 0.05) on finishing gain, feed intake, and feed:gain. Steers supplemented with the starch-based supplement had greater (P \u3c 0.05) final finishing liveweight, and greater (P \u3c 0.05) hot carcass weight than those that received no supplement. In 2015, steers supplemented with the fat-based supplement had higher (P \u3c 0.05) final finishing liveweight and hot carcass weight and lower (P \u3c 0.05) finishing gain than those supplemented with the starch-based supplement or fed no supplement
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