309 research outputs found

    Distinguishing extensive and intensive properties for meaningful geocomputation and mapping

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    A most fundamental and far-reaching trait of geographic information is the distinction between extensive and intensive properties. In common understanding, originating in Physics and Chemistry, extensive properties increase with the size of their supporting objects, while intensive properties are independent of this size. It has long been recognized that the decision whether analytical and cartographic measures can be meaningfully applied depends on whether an attribute is considered intensive or extensive. For example, the choice of a map type as well as the application of basic geocomputational operations, such as spatial intersections, aggregations or algebraic operations such as sums and weighted averages, strongly depend on this semantic distinction. So far, however, the distinction can only be drawn in the head of an analyst. We still lack practical ways of automation for composing GIS workflows and to scale up mapping and geocomputation over many data sources, e.g. in statistical portals. In this article, we test a machine-learning model that is capable of labeling extensive/ intensive region attributes with high accuracy based on simple characteristics extractable from geodata files. Furthermore, we propose an ontology pattern that captures central applicability constraints for automating data conversion and mapping using Semantic Web technology

    Comment on "Mean First Passage Time for Anomalous Diffusion"

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    We correct a previously erroneous calculation [Phys. Rev. E 62, 6065 (2000)] of the mean first passage time of a subdiffusive process to reach either end of a finite interval in one dimension. The mean first passage time is in fact infinite.Comment: To appear in Phys. Rev.

    Finding and sharing GIS methods based on the questions they answer

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    Geographic information has become central for data scientists of many disciplines to put their analyses into a spatio-temporal perspective. However, just as the volume and variety of data sources on the Web grow, it becomes increasingly harder for analysts to be familiar with all the available geospatial tools, including toolboxes in Geographic Information Systems (GIS), R packages, and Python modules. Even though the semantics of the questions answered by these tools can be broadly shared, tools and data sources are still divided by syntax and platform-specific technicalities. It would, therefore, be hugely beneficial for information science if analysts could simply ask questions in generic and familiar terms to obtain the tools and data necessary to answer them. In this article, we systematically investigate the analytic questions that lie behind a range of common GIS tools, and we propose a semantic framework to match analytic questions and tools that are capable of answering them. To support the matching process, we define a tractable subset of SPARQL, the query language of the Semantic Web, and we propose and test an algorithm for computing query containment. We illustrate the identification of tools to answer user questions on a set of common user requests

    Psychological climates in action learning sets: A manager’s perspective

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    Action Learning (AL) is often viewed as a process that facilitates professional learning through the creation of a positive psychological climate (Marquart, 2000; Schein, 1979). An psychological climate that fosters an environment in which learning set members feel psychologically safe enough to reflect upon both the successes, and failures in their professional life without any form of repercussion. However, there has been little attention given to the ways that that psychological climate develops, and the differing facets that create that climate. In response to such deficit, this paper reports the outcomes of interviews with eleven managers, all of whom are former AL set members on their experiences of action learning set membership. Drawing upon an interpretivist philosophy, the paper explores the key themes that emerged from the analysis of those interviews. The analysis serves to illustrate the differing facets that collectively contribute creation of a positive psychological climate that is conducive for learning. Analysis points to the relative importance of such facets as: trust, honesty, vulnerability, reciprocity, confidentiality and personal disclosure, all of which have the capacity to lead to a positive psychological climate in action learning sets. This paper is useful for developing an understanding of the differing facets in AL sets that create a psychological climate conducive for learning. As such, it has utility for action learning facilitators, set members, academics and educational consultants

    Electrode Polarization Effects in Broadband Dielectric Spectroscopy

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    In the present work, we provide broadband dielectric spectra showing strong electrode polarization effects for various materials, belonging to very different material classes. This includes both ionic and electronic conductors as, e.g., salt solutions, ionic liquids, human blood, and colossal-dielectric-constant materials. These data are intended to provide a broad data base enabling a critical test of the validity of phenomenological and microscopic models for electrode polarization. In the present work, the results are analyzed using a simple phenomenological equivalent-circuit description, involving a distributed parallel RC circuit element for the modeling of the weakly conducting regions close to the electrodes. Excellent fits of the experimental data are achieved in this way, demonstrating the universal applicability of this approach. In the investigated ionically conducting materials, we find the universal appearance of a second dispersion region due to electrode polarization, which is only revealed if measuring down to sufficiently low frequencies. This indicates the presence of a second charge-transport process in ionic conductors with blocking electrodes.Comment: 9 pages, 6 figures, experimental data are provided in electronic form (see "Data Conservancy"

    DNA methylation of FKBP5 and response to exposure-based psychological therapy

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    Differential DNA methylation of the HPA-axis related gene FKBP5 has recently been shown to be associated with varying response to environmental influences, and may play a role in how well people respond to psychological treatments. Participants (n=111) received exposure-based CBT for agoraphobia with or without panic disorder, or specific phobias. Percentage DNA methylation levels were measured for the promoter region and intron 7 of FKBP5. The association between percentage reduction in clinical severity and change in DNA methylation was tested using linear mixed models. The effect of genotype (rs1360780) was tested by the inclusion of an interaction term. The association between change in DNA methylation and FKBP5 expression was examined. Change in percentage DNA methylation at one CpG site of intron 7 was associated with percentage reduction in severity (β=-4.26, p=3.90x10-4), where a decrease in DNA methylation was associated with greater response to therapy. An interaction was detected between rs1360780 and changes in DNA methylation in the promoter region of FKBP5 on treatment outcome (p=0.045), but did not survive correction for multiple testing. Changes in DNA methylation were not associated with FKBP5 expression. Decreasing DNA methylation at one CpG site of intron 7 of FKBP5 was strongly associated with decreasing anxiety severity following exposure-based CBT. In addition, there was suggestive evidence that allele-specific methylation at the promoter region may also be associated with treatment response. The results of this study add to the growing literature demonstrating the role of biological processes such as DNA methylation in response to environmental influences

    Linear and nonlinear optical properties of realistic quantum-wire structures: The dominant role of Coulomb correlation

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    A systematic analysis of the linear and nonlinear optical properties of realistic quantum wires is presented. The proposed theoretical approach, based on a set of generalized semiconductor Bloch equations, provides a full three-dimensional multisubband description of carrier-carrier correlation for any profile of the confinement potential, thus allowing a direct comparison with experiments on available structures. In agreement with previous investigations based on simplified one-dimensional models, our analysis shows that, also for realistic quantum-wire structures, electron-hole Coulomb correlation completely removes the one-dimensional band-edge singularities from the linear-absorption spectra. Moreover, we find that this effect is present also at high densities (corresponding to gain regimes) and contributes significantly in suppressing the ideal sharp features of the free-carrier density of states. The multisubband nature of available state-of-the-art structures is found to play a dominant role in determining the overall spectral shape in the whole density range

    Social use of facial expressions in hylobatids

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    Non-human primates use various communicative means in interactions with others. While primate gestures are commonly considered to be intentionally and flexibly used signals, facial expressions are often referred to as inflexible, automatic expressions of affective internal states. To explore whether and how non-human primates use facial expressions in specific communicative interactions, we studied five species of small apes (gibbons) by employing a newly established Facial Action Coding System for hylobatid species (GibbonFACS). We found that, despite individuals often being in close proximity to each other, in social (as opposed to non-social contexts) the duration of facial expressions was significantly longer when gibbons were facing another individual compared to non-facing situations. Social contexts included grooming, agonistic interactions and play, whereas non-social contexts included resting and self-grooming. Additionally, gibbons used facial expressions while facing another individual more often in social contexts than non-social contexts where facial expressions were produced regardless of the attentional state of the partner. Also, facial expressions were more likely ‘responded to’ by the partner’s facial expressions when facing another individual than non-facing. Taken together, our results indicate that gibbons use their facial expressions differentially depending on the social context and are able to use them in a directed way in communicative interactions with other conspecifics

    The evolution of diabetic chronic complications after pancreas transplantation

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    Pancreas transplantation is an invasive procedure that can restore and maintain normoglycemic level very successfully and for a prolonged period in DM1 patients. The procedure elevates the morbimortality rates in the first few months following the surgery if compared to kidney transplants with living donors, but it offers a better quality of life to patients
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