280 research outputs found
Impacts of climate change on air pollution levels in the Northern Hemisphere with special focus on Europe and the Arctic
International audienceThe response of a selected number of chemical species is inspected with respect to climate change. The coupled Atmosphere-Ocean General Circulation Model ECHAM4-OPYC3 is providing meteorological fields for the Chemical long-range Transport Model DEHM. Three selected decades (1990s, 2040s and 2090s) are inspected. The 1990s are used as a reference and validation period. In this decade an evaluation of the output from the DEHM model with ECHAM4-OPYC3 meteorology input data is carried out. The model results are tested against similar model simulations with MM5 meteorology and against observations from the EMEP monitoring sites in Europe. The test results from the validation period show that the overall statistics (e.g. mean values and standard deviations) are similar for the two simulations. However, as one would expect the model setup with climate input data fails to predict correctly the timing of the variability in the observations. The overall performance of the ECHAM4-OPYC3 setup as meteorological input to the DEHM model is shown to be acceptable according to the applied ranking method. It is concluded that running a chemical long-range transport model on data from a "free run" climate model is scientifically sound. From the model runs of the three decades, it is found that the overall trend detected in the evolution of the chemical species, is the same between the 1990 decade and the 2040 decade and between the 2040 decade and the 2090 decade, respectively. The dominating impacts from climate change on a large number of the chemical species are related to the predicted temperature increase. Throughout the 21th century the ECHAM4-OPYC3 projects a global mean temperature increase of 3 K with local maxima up to 11 K in the Arctic winter based on the IPCC A2 emission scenario. As a consequence of this temperature increase, the temperature dependent biogenic emission of isoprene is predicted to increase significantly over land by the DEHM model. This leads to an increase in the O3 production and together with an increase in water vapor to an increase in the number of free OH radicals. Furthermore this increase in the number of OH radicals contributes to a significant change in the typical life time of many species, since OH are participating in a large number of chemical reactions. It is e.g. found that more SO42? will be present in the future over the already polluted areas and this increase can be explained by an enhanced conversion of SO2 to SO42?
Operational river discharge forecasting in poorly gauged basins: the Kavango River Basin case study
Operational probabilistic forecasts of river discharge are essential for
effective water resources management. Many studies have addressed this topic
using different approaches ranging from purely statistical black-box
approaches to physically based and distributed modeling schemes employing
data assimilation techniques. However, few studies have attempted to develop
operational probabilistic forecasting approaches for large and poorly gauged
river basins. The objective of this study is to develop open-source software
tools to support hydrologic forecasting and integrated water resources
management in Africa. We present an operational probabilistic forecasting
approach which uses public-domain climate forcing data and a
hydrologic–hydrodynamic model which is entirely based on open-source
software. Data assimilation techniques are used to inform the forecasts with
the latest available observations. Forecasts are produced in real time for
lead times of 0–7 days. The operational probabilistic forecasts are
evaluated using a selection of performance statistics and indicators and the
performance is compared to persistence and climatology benchmarks. The
forecasting system delivers useful forecasts for the Kavango River, which
are reliable and sharp. Results indicate that the value of the forecasts is
greatest for intermediate lead times between 4 and 7 days
Parental cultural models and resources for understanding mathematical achievement in culturally diverse school settings
This paper proposes that the theoretical concept of cultural models can offer useful insights into parental involvement in their child’s mathematical achievement and the resources they use to go about gaining information in culturally diverse learning settings. This examination takes place within a cultural-developmental framework and draws on the notion of cultural models to explicate parental understandings of their child’s mathematics achievement and what resources are used to make sense of this. Three parental resources are scrutinized: (a) the teacher, (b) examination test results, and (c) constructions of child development. The interviews with 22 parents revealed some ambiguity around the interpretation of these resources by the parent, which was often the result of incongruent cultural models held between the home and the school. The resources mentioned are often perceived as being unambiguous but show themselves instead to be highly interpretive because of the diversity of cultural models in existence in culturally diverse settings. Parents who are in minority or marginalized positions tend to have difficulties in interpreting cultural models held by school, thereby disempowering them to be parentally involved in the way the school would like
Methods for interpreting lists of affected genes obstained in a DNA microarray experiment
Background - The aim of this paper was to describe and compare the methods used and the results obtained by the participants in a joint EADGENE (European Animal Disease Genomic Network of Excellence) and SABRE (Cutting Edge Genomics for Sustainable Animal Breeding) workshop focusing on post analysis of microarray data. The participating groups were provided with identical lists of microarray probes, including test statistics for three different contrasts, and the normalised log-ratios for each array, to be used as the starting point for interpreting the affected probes. The data originated from a microarray experiment conducted to study the host reactions in broilers occurring shortly after a secondary challenge with either a homologous or heterologous species of Eimeria. Results - Several conceptually different analytical approaches, using both commercial and public available software, were applied by the participating groups. The following tools were used: Ingenuity Pathway Analysis, MAPPFinder, LIMMA, GOstats, GOEAST, GOTM, Globaltest, TopGO, ArrayUnlock, Pathway Studio, GIST and AnnotationDbi. The main focus of the approaches was to utilise the relation between probes/genes and their gene ontology and pathways to interpret the affected probes/genes. The lack of a well-annotated chicken genome did though limit the possibilities to fully explore the tools. The main results from these analyses showed that the biological interpretation is highly dependent on the statistical method used but that some common biological conclusions could be reached. Conclusion - It is highly recommended to test different analytical methods on the same data set and compare the results to obtain a reliable biological interpretation of the affected genes in a DNA microarray experimen
Operational river discharge forecasting in poorly gauged basins: the Kavango River basin case study
Operational probabilistic forecasts of river discharge are essential for
effective water resources management. Many studies have addressed this topic
using different approaches ranging from purely statistical black-box
approaches to physically based and distributed modeling schemes employing
data assimilation techniques. However, few studies have attempted to develop
operational probabilistic forecasting approaches for large and poorly gauged
river basins. The objective of this study is to develop open-source software
tools to support hydrologic forecasting and integrated water resources
management in Africa. We present an operational probabilistic forecasting
approach which uses public-domain climate forcing data and a
hydrologic–hydrodynamic model which is entirely based on open-source
software. Data assimilation techniques are used to inform the forecasts with
the latest available observations. Forecasts are produced in real time for
lead times of 0–7 days. The operational probabilistic forecasts are
evaluated using a selection of performance statistics and indicators and the
performance is compared to persistence and climatology benchmarks. The
forecasting system delivers useful forecasts for the Kavango River, which
are reliable and sharp. Results indicate that the value of the forecasts is
greatest for intermediate lead times between 4 and 7 days
Perspectives on the ‘silent period’ for emergent bilinguals in England
This paper draws together the research findings from two ethnographic studies (Drury, 2007; Bligh, 2011) as a means to problematize the ‘silent period’ as experienced by young bilingual learners in two English speaking early years settings in England. Most teachers and senior early years practitioners in England are monolingual English speakers. The children (regardless of their mother tongue) are taught through the medium of spoken and written English in and through all subject areas. Bilingual learning through the mother tongue is not only disregarded in most schools in England but is actively discouraged in some.
Three emergent bilingual learners were re-examined as case studies. Suki and Adyta (Bligh, 2011) of Japanese and Punjabi decent and Nazma (Drury, 2007) of Kashmiri descent were observed whilst they each negotiated new ways of knowing within and through an English pre-school setting. Sociocultural insights into how these young children employ their silenced mother tongue to negotiate their learning creates a fuller and richer portrait of the emergent bilingual learner both in and outside of preschool.
These collaborative research findings present the silent period as agentive (Drury, 2007) and as a crucial time for self-mediated learning (Bligh, 2011) within the early years community of practice
Teaching Writing: a situated dynamic
publication-status: Publishedtypes: ArticleThe paper is theoretically grounded in Cultural Historical Activity Theory (CHAT) which holds that human development is founded within participation in social and cultural practices. In particular, the teaching of literacy is shaped not only by the curriculum as designated by policy makers and the institution in which it is located but also by the individuals’ understanding of what literacy and learning involves and how they act to achieve their goals. The paper explores data from a project that investigated the relationship between classroom talk and the teaching of writing in six early years classrooms. Participants’ own understandings of teaching and learning need to be taken into account by researchers and policy makers. CHAT has been used to explore the dynamic relationship between activity at societal, institutional and individual levels. It is argued that researchers and policy makers need to take account of the wider socio-cultural context in planning and evaluating curriculum development initiatives
Re-imaging Bernstein's restricted codes
While accepting that the concept of restricted code has a troubled history that resulted in Bernstein being associated with deficit models of working-class life, it is argued that the concept should be re-imagined rather than abandoned. Bernstein’s early work refers to restricted code as a form of condensed, shorthand established through familiarity that was not tied to class per se. In Volume 2 of Class, Codes and Control social class was an independent variable in the research designs and coding only that which could be explicitly spoken, produced working class groups as inferior in comparison to middle class groups: Bernstein’s disquiet can be sensed in many places across his work where he explicitly renounced a deficit model. Methodological and theoretical work on embodied knowledge is used here to explicate the more-than, codeable features of restricted codes. An illustration from studies in ex-coalmining, working-class communities is used to explore what is missed in conventional approaches to data coding. Other studies in ex-mining communities reveal the intergenerational transmission of rich resources that were vital for community survival. Re-imagining restricted codes as relational assemblages recognises the value of the dynamic, creative and intergenerational features of localised, embodied knowledge
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