4,190 research outputs found
Currnent and likely future performance of advanced natural ventilation
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
Sustainable refurbishment solutions for high-rise residential buildings in subtropical areas
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
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
A panel model for predicting the diversity of internal temperatures from English dwellings
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
Evidence-informed health policy: are we beginning to get there at last
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
Development and Bias Assessment of a Method for Targeted Metagenomic Sequencing of Marine Cyanobacteria
Prochlorococcus and Synechococcus are the most abundant photosynthetic organisms in oligotrophic waters and responsible for a significant percentage of the earth's primary production. Here we developed a method for metagenomic sequencing of sorted Prochlorococcus and Synechococcus populations using a transposon-based library preparation technique. First, we observed that the cell lysis technique and associated amount of input DNA had an important role in determining the DNA library quality. Second, we found that our transposon-based method provided a more even coverage distribution and matched more sequences of a reference genome than multiple displacement amplification, a commonly used method for metagenomic sequencing. We then demonstrated the method on Prochlorococcus and Synechococcus field populations from the Sargasso Sea and California Current isolated by flow cytometric sorting and found clear environmentally related differences in ecotype distributions and gene abundances. In addition, we saw a significant correspondence between metagenomic libraries sequenced with our technique and regular sequencing of bulk DNA. Our results show that this targeted method is a viable replacement for regular metagenomic approaches and will be useful for identifying the biogeography and genome content of specific marine cyanobacterial populations
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Seasonal changes in water quality and Sargassum biomass in southwest Australia
Sargassum C. Agardh is one of the most diverse genera of marine macro-algae and commonly inhabits shallow tropical and sub-tropical waters. This study aimed to investigate the effect of seasonality and the associated water quality changes on the distribution, canopy cover, mean thallus length and the biomass of Sargassum beds around Point Peron, Shoalwater Islands Marine Park, Southwest Australia. Samples of Sargassum and seawater were collected every three months from summer 2012 to summer 2014 from four different reef zones. A combination of in situ observations and WorldView-2 satellite remote-sensing images were used to map the spatial
distribution of Sargassum beds and other associated benthic habitats. The results demonstrated a strong seasonal variation in the environmental parameters, canopy cover, mean thallus length, and biomass of Sargassum, which were significantly (P < 0.05) influenced by the nutrient concentration (PO43-, NO3-, NH4+) and rainfall. However, no variation in any studied parameter was observed among the four reef zones. The highest Sargassum biomass peaks occurred between late spring and early summer (from September to January). The results provide essential information to guide effective conservation and management, as well as sustainable utilisation of this coastal marine renewable resource
Using MODIS to detect cropping frequency variation in mechanized agriculture in Amazonia.
Policy makers concerned with managing rapidly developing agriculture on the Amazon frontier currently have no Basin-wide spatial and temporal information on exactly when and how soubean and other mechanized annual cropping have developed in the region. To address this, we present a reliminary evaluation of the use of moderate resolution Imaging Spectroradiometer (MODIS) 250 m vegetation index (VI) time-series data to detect croppping frequency in two municipalities, Vilhena, Rondônia, and Santarém, Pará
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The Search Image Hypothesis in Animal behavior: Its Relevance to Analyzing Vision at the Complexity Level
We show how a concept from animal behavior, the visual search hypothesis, is relevant to complexity considerations in computational vision. In particular we show that this hypothesis is an indication of the validity of the bounded/unbounded visual search distinction proposed by Tsotsos. Specifically we show bounded visual search corresponds to a broad range of naturally occurring, target driven problems in which attention alters the search behavior of animals
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