182,594 research outputs found

    School starters’ early structure sense

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    Low and high achieving children’s competences regarding pattern and structure at the beginning of formal schooling are comparatively analyzed in order to evaluate the range of school starters’ early structure sense. The results suggest overall high pre-instructional competences which, however, differ strongly between the mathematical high and low achievers. Cognitive milestones for the development of a sound early structure sense are named

    Comparing discrete choice models: some housing market examples

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    Introduction: Since the mid nineteen seventies there has been strong interest within variolls branches of social science in the adaptation of the discrete choice modeling methodology towards a wide range of research problems. This has required recognition of a wide variety of alternative decision-contexts (Landau et a1. 1982) and behaviour-patterns (Lerman, 1979), and has also raised general issues concerning the variable extent to which individual or subgroup choices may be restricted by spatial and temporal constraints. Further interest has been expressed about the spatial and temporal transferability of alternative discrete choice models (Atherton and Ben-Akiva, 1976: Galbraith and Hensher, 1982). This substantive diversification has been accompanied by a variety of technical and methodological refinements of the multinomiallogit (MNL) and multinomial probit (MNP) models, ranging from new estimation procedures (Hausman and Wise, 1978) to the development of less-restrictive, computationally tractable discrete choice model forms (for example, Williams, 1977: Daly and Zachary, 1978). Faced with both a wider selection of methodological tools and a broader spectrum of substantive enquiry, there exists a clear need for formal comparison procedures which the analyst can call upon to evaluate a given model specification or framework. In this paper, I attempt to review briefly some trends amongst recent housing choice studies which employ discrete choice modeling methods. A new procedure is then presented (Hubert and Golledge, 1981; Halperin et al. 1984) which may be used to compare discrete choice models specified and/or structured in accordance with different a priori hypotheses. It is argued that this method fills a gap between existing discrete choice model comparison-procedures which are inapplicable to 'nonnested' model specifications, that is, to competing discrete choice models which comprise totally different variable specifications and that such procedures can usefully aid selection of the discrete choice model most appropriate to any given decision context

    A review of Australian approaches for monitoring, assessing and reporting estuarine condition: III. Evaluation against international best practice and recommendations for the future

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    In this final component of a three-part review, we present a national synthesis and evaluation of approaches for monitoring, assessing and reporting estuarine condition across Australia. Progress is evaluated against objective criteria that together provide a model of international best practice. We critically assess the limitations, inconsistencies and gaps that are evident across Australian jurisdictions, and identify common obstacles to future progress. Major strengths and successes are also highlighted, together with specific examples of best practice from around Australia that are transferable to other States and beyond. Significant obstacles to greater national coordination of monitoring and reporting practices include inconsistent spatial scales of management, pluralistic governance structures and the lack of any overarching legislation. Nonetheless, many perceptible advances have been made over the last decade across Australia in estuarine monitoring and health assessment, and there is great potential for further progress. Finally, we provide a list of recommendations to address some of the most pressing limitations and gaps, and support improved future monitoring, assessment and reporting for Australian estuaries

    Addressing the selective role of distinct prefrontal areas in response suppression: A study with brain tumor patients

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    The diverging evidence for functional localization of response inhibition within the prefrontal cortex might be justified by the still unclear involvement of other intrinsically related cognitive processes like response selection and sustained attention. In this study, the main aim was to understand whether inhibitory impairments, previously found in patients with both left and right frontal lesions, could be better accounted for by assessing these potentially related cognitive processes. We tested 37 brain tumor patients with left prefrontal, right prefrontal and non-prefrontal lesions and a healthy control group on Go/No-Go and Foreperiod tasks. In both types of tasks inhibitory impairments are likely to cause false alarms, although additionally the former task requires response selection and the latter target detection abilities. Irrespective of the task context, patients with right prefrontal damage showed frequent Go and target omissions, probably due to sustained attention lapses. Left prefrontal patients, on the other hand, showed both Go and target omissions and high false alarm rates to No-Go and warning stimuli, suggesting a decisional rather than an inhibitory impairment. An exploratory whole-brain voxel-based lesion-symptom mapping analysis confirmed the association of left ventrolateral and dorsolateral prefrontal lesions with target discrimination failure, and right ventrolateral and medial prefrontal lesions with target detection failure. Results from this study show how left and right prefrontal areas, which previous research has linked to response inhibition, underlie broader cognitive control processes, particularly involved in response selection and target detection. Based on these findings, we suggest that successful inhibitory control relies on more than one functionally distinct process which, if assessed appropriately, might help us to better understand inhibitory impairments across different pathologies

    Structural analyses of features in cultural landscapes based on historical cadastral maps and GIS

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    A landscape may appear to be ancient and to contain old man-made structures even if this is not the whole truth. Structures are moved, removed, replaced and added over the years. New users introduce new land use and management regimes. In Norway, information from land consolidation processes is crucially important in gaining a better understanding of the history, dynamics and development of farms, identifying older traces of human activity and selecting important areas for protection and management. When cadastral maps are transformed, common points are needed during the transformation process and for testing the accuracy of the final transformation. It is often difficult to find enough common points to satisfy statistical requirements. Paper I presents a simple method using buffers based on linear features to evaluate whether or not the accuracy of the transformation results is better than the known accuracy of the source. Papers II, III and IV show how digitised and geographically referenced historical cadastral maps can be used to reconstruct the situation at various dates back to the 19th century, and for some information back to the 16th century. The digitised cadastral map provides a snapshot of the situation at the time of the land consolidation process, and the information is considered to be very exact. Paper IV also demonstrates how a DEM (digital elevation model) can add significantly to an understanding of the information contained in the land consolidation material. The use of digitised cadastral maps reveals that many man-made structures generally perceived as old, because they are constructed using traditional techniques, in fact date from after the land consolidation process. One aim of the new European Landscape Convention is to promote landscape protection, management and planning. It therefore requires identification of landscapes and analysis of their characteristics and the forces and pressures transforming them. Using land consolidation material in a GIS makes it possible to document changes in a landscape and improve understanding of the pressures behind these changes

    Environmental urbanization assessment using gis and multicriteria decision analysis: a case study for Denizli (Turkey) municipal area

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    In recent years, life quality of the urban areas is a growing interest of civil engineering. Environmental quality is essential to display the position of sustainable development and asserts the corresponding countermeasures to the protection of environment. Urban environmental quality involves multidisciplinary parameters and difficulties to be analyzed. The problem is not only complex but also involves many uncertainties, and decision-making on these issues is a challenging problem which contains many parameters and alternatives inherently. Multicriteria decision analysis (MCDA) is a very prepotent technique to solve that sort of problems, and it guides the users confidence by synthesizing that information. Environmental concerns frequently contain spatial information. Spatial multicriteria decision analysis (SMCDA) that includes Geographic Information System (GIS) is efficient to tackle that type of problems. This study has employed some geographic and urbanization parameters to assess the environmental urbanization quality used by those methods. The study area has been described in five categories: very favorable, favorable, moderate, unfavorable, and very unfavorable. The results are momentous to see the current situation, and they could help to mitigate the related concerns. The study proves that the SMCDA descriptions match the environmental quality perception in the city. © 2018 Erdal Akyol et al

    On the accuracy of simulations of turbulence

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    The widely recognized issue of adequate spatial resolution in numerical simulations of turbulence is studied in the context of two-dimensional magnetohydrodynamics. The familiar criterion that the dissipation scale should be resolved enables accurate computation of the spectrum, but fails for precise determination of higher-order statistical quantities. Examination of two straightforward diagnostics, the maximum of the kurtosis and the scale-dependent kurtosis, enables the development of simple tests for assessing adequacy of spatial resolution. The efficacy of the tests is confirmed by examining a sample problem, the distribution of magnetic reconnection rates in turbulence. Oversampling the Kolmogorov dissipation scale by a factor of 3 allows accurate computation of the kurtosis, the scale-dependent kurtosis, and the reconnection rates. These tests may provide useful guidance for resolution requirements in many plasma computations involving turbulence and reconnection

    Measuring the vulnerability of the Uruguayan population to vector-borne diseases via spatially hierarchical factor models

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    We propose a model-based vulnerability index of the population from Uruguay to vector-borne diseases. We have available measurements of a set of variables in the census tract level of the 19 Departmental capitals of Uruguay. In particular, we propose an index that combines different sources of information via a set of micro-environmental indicators and geographical location in the country. Our index is based on a new class of spatially hierarchical factor models that explicitly account for the different levels of hierarchy in the country, such as census tracts within the city level, and cities in the country level. We compare our approach with that obtained when data are aggregated in the city level. We show that our proposal outperforms current and standard approaches, which fail to properly account for discrepancies in the region sizes, for example, number of census tracts. We also show that data aggregation can seriously affect the estimation of the cities vulnerability rankings under benchmark models.Comment: Published in at http://dx.doi.org/10.1214/11-AOAS497 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org
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