26 research outputs found
Bioclimatic Architecture and Urban Morphology. Studies on Intermediate Urban Open Spaces
This paper deals with the interactions between biophysical and microclimatic factors
on the one hand with, on the other, the urban morphology of intermediate urban open spaces,
the relationship between environmental and bioclimatic thermal comfort, and the implementation of
innovative materials and the use of greenery, aimed at the users’ well-being. In particular, the thermal
comfort of the open spaces of the consolidated fabrics of the city of Rome is studied, by carrying
out simulations of cooling strategies relating to two scenarios applied to Piazza Bainsizza. The first
scenario involves the use of cool materials for roofs, cladding surfaces, and pavement, while the
second scenario, in addition to the cool materials employed in the first scenario, also includes the use
of greenery and permeable green surfaces. The research was performed using summer and winter
microclimatic simulations of the CFD (ENVI-met v. 3.1) type, in order to determine the dierent
influences of the materials with cold colors, trees, and vegetated surfaces on the thermal comfort
of the urban morphology itself. Meanwhile, the comfort assessment was determined through the
physiological equivalent temperature (PET) calculated with the RayMan program. The first scenario,
with the use of cool materials, improves summer conditions and reduces the urban heat island
eect but does not eliminate thermal discomfort due to the lack of shaded surfaces and vegetation.
The second scenario, where material renovations is matched with vegetation improvements, has a
slightly bad eect on winter conditions but drastically ameliorates the summer situation, both for
direct users and, thanks to the strong reduction of the urban heat island eect, to urban inhabitants as
a whole
Influence of seasonality and vegetation type on suburban microclimates
Urbanization is responsible for some of the fastest rates of land-use change around the world, with important consequences for local, regional, and global climate. Vegetation, which represents a significant proportion of many urban and suburban landscapes, can modify climate by altering local exchanges of heat, water vapor, and CO2. To determine how distinct urban forest communities vary in their microclimate effects over time, we measured stand-level leaf area index, soil temperature, infrared surface temperature, and soil water content over a complete growing season at 29 sites representing the five most common vegetation types in a suburban neighborhood of Minneapolis–Saint Paul, Minnesota. We found that seasonal patterns of soil and surface temperatures were controlled more by differences in stand-level leaf area index and tree cover than by plant functional type. Across the growing season, sites with high leaf area index had soil temperatures that were 7°C lower and surface temperatures that were 6°C lower than sites with low leaf area index. Site differences in mid-season soil temperature and turfgrass ground cover were best explained by leaf area index, whereas differences in mid-season surface temperature were best explained by percent tree cover. The significant cooling effects of urban tree canopies on soil temperature imply that seasonal changes in leaf area index may also modulate CO2 efflux from urban soils, a highly temperature-dependent process, and that this should be considered in calculations of total CO2 efflux for urban carbon budgets. Field-based estimates of percent tree cover were found to better predict mid-season leaf area index than satellite-derived estimates and consequently offer an approach to scale up urban biophysical properties
Science teachers’ experiences of inquiry-based learning through a serious game:a phenomenographic perspective
This study employed a phenomenographic approach to investigate science teachers’ conceptions of inquiry-based learning through a serious game. Simaula is a prototype game designed and used as a virtual practicum for eliciting understandings on how in-game inquiry was appeared to, or experienced by, the participating teachers. Group interviews with 20 secondary education science teachers revealed four qualitatively different ways of experiencing inquiry-based learning through Simaula: (a) as uncovering insights about student’s learning needs, interests and emotions; (b) as generating ideas and concepts for meaningful inquiry; (c) as a set of operations for designing and carrying out scientific research; and (d) as authentic inquiry for enabling knowledge building processes. Seven dimensions of variation have been identified viewed as contextual influences on conceptions of in-game inquiry constituting discernment of: epistemic inquiry-based learning modes; role of teacher; role of student; game-play focus; core mechanics focus; feedback and progress mechanics and game uncertainty. The results illuminated a partial in-game inquiry approach with distinct epistemic modes from developing empathy and meaning making to knowledge construction and knowledge building. The findings also indicated that game design elements played central role in shaping conceptions of in-game inquiry from focusing on rules and logic as means to completing the game’s level to understanding the complexity of core mechanics for developing and transferring in-game inquiry to the real classroom. This insinuates that distinct game design properties may be considered in terms of extending intrinsic in-game inquiry experiences to actual in-class inquiry practice
Analysis of the wind field and heat budget in an alpine lake basin during summertime fair weather conditions
Observational data collected in the Lake Tekapo hydro catchment of the Southern Alps in New Zealand are used to analyse the wind and temperature fields in the alpine lake basin during summertime fair weather conditions. Measurements from surface stations, pilot balloon and tethersonde soundings, Doppler sodar and an instrumented light aircraft provide evidence of multi-scale interacting wind systems, ranging from microscale slope winds to mesoscale coast-to-basin flows. Thermal forcing of the winds occurred due to differential heating as a consequence of orography and heterogeneous surface features, which is quantified by heat budget and pressure field analysis. The daytime vertical temperature structure was characterised by distinct layering. Features of particular interest are the formation of thermal internal boundary layers due to the lake-land discontinuity and the development of elevated mixed layers. The latter were generated by advective heating from the basin and valley sidewalls by slope winds and by a superimposed valley wind blowing from the basin over Lake Tekapo and up the tributary Godley Valley. Daytime heating in the basin and its tributary valleys caused the development of a strong horizontal temperature gradient between the basin atmosphere and that over the surrounding landscape, and hence the development of a mesoscale heat low over the basin. After noon, air from outside the basin started flowing over mountain saddles into the basin causing cooling in the lowest layers, whereas at ridge top height the horizontal air temperature gradient between inside and outside the basin continued to increase. In the early evening, a more massive intrusion of cold air caused rapid cooling and a transition to a rather uniform slightly stable stratification up to about 2000 m agl. The onset time of this rapid cooling varied about 1-2 h between observation sites and was probably triggered by the decay of up-slope winds inside the basin, which previously countered the intrusion of air over the surrounding ridges. The intrusion of air from outside the basin continued until about mid-night, when a northerly mountain wind from the Godley Valley became dominant. The results illustrate the extreme complexity that can be caused by the operation of thermal forcing processes at a wide range of spatial scales
Genomewide Analysis of Reassortment and Evolution of Human Influenza A(H3N2) Viruses Circulating between 1968 and 2011
Influenza A(H3N2) viruses became widespread in humans during the 1968 H3N2 virus pandemic and have been a major cause of influenza epidemics ever since. These viruses evolve continuously by reassortment and genomic evolution. Antigenic drift is the cause for the need to update influenza vaccines frequently. Using two data sets that span the entire period of circulation of human influenza A(H3N2) viruses, it was shown that influenza A(H3N2) virus evolution can be mapped to 13 antigenic clusters. Here we analyzed the full genomes of 286 influenza A(H3N2) viruses from these two data sets to investigate the genomic evolution and reassortment patterns. Numerous reassortment events were found, scattered over the entire period of virus circulation, but most prominently in viruses circulating between 1991 and 1998. Some of these reassortment events persisted over time, and one of these coincided with an antigenic cluster transition. Furthermore, selection pressures and nucleotide and amino acid substitution rates of all proteins were studied, including those of the recently discovered PB1-N40, PA-X, PA-N155, and PA-N182 proteins. Rates of nucleotide and amino acid substitutions were most pronounced for the hemagglutinin, neuraminidase, and PB1-F2 proteins. Selection pressures were highest in hemagglutinin, neuraminidase, matrix 1, and nonstructural protein 1. This study of genotype in relation to antigenic phenotype throughout the period of circulation of human influenza A(H3N2) viruses leads to a better understanding of the evolution of these viruses. IMPORTANCE Each winter, influenza virus infects approximately 5 to 15% of the world's population, resulting in significant morbidity and mortality. Influenza A(H3N2) viruses evolve continuously by reassortment and genomic evolution. This leads to changes in antigenic recognition (antigenic drift) which make it necessary to update vaccines against influenza A(H3N2) viruses frequently. In this study, the relationship of genetic evolution to antigenic change spanning the entire period of A(H3N2) virus circulation was studied for the first time. The results presented in this study contribute to a better understanding of genetic evolution in correlation with antigenic evolution of influenza A(H3N2) viruses