128 research outputs found

    Determination of thermal response of Carrara and Sneznikovsky marble used as building material

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    Physical weathering of marble, widely used as a cladding material on buildings, is one of the most common damaging mechanism caused by anisotropic thermal expansion of calcite grains. The extent of marble deterioration depends mainly on stone fabric and texture. Dry cuboids of Carrara marble and marble from Dolni Morava quarry were subjected to microscopic analysis and thermal cycling, to determine the thermal expansion related to stone fabric and predominant lattice orientation of grains (i.e. texture)

    Evaluating the processes and outcomes of vocational counselling: An action theory perspective

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    In the context of current research in, and calls for, evidence-based practice, an action theory perspective is proposed for the evaluation of vocational counselling and other career guidance interventions. The proposition of an action theory perspective, which is based on the common understanding of human experience as being goal-directed, is made in light of several issues in the philosophy of science relevant to evaluation, including the role accorded common sense, the tension between evaluating processes and outcomes, how meaning is represented, how quality is judged, and the place of the intentionality of human agents. The specifics of this integrative approach for evaluation include the continuity of action, project, and career, as well as goals, functional steps, and behavioural and other elements that comprise them. These systems operate in vocational counselling itself, as well as in other systems of which counselling is a part. The research evidence on vocational counselling reflects the goal-directed processes that the perspective enunciates

    La notion de projet en psychologie de l’orientation

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    La notion de projet apparaît comme un concept pertinent en psychologie de l’orientation. Bien qu’également utilisé dans un sens général, le projet a été récemment conceptualisé d’une manière spécifique dans cette discipline. Ces deux sens renvoient à sa nature sociale et intentionnelle, à ses perspectives temporelles et à ses caractères à la fois multi déterminés et indéterminables. Ces significations trouvent leur fondement dans la théorie sociale de l’action. Ces fondements permettent de considérer le concept de projet comme étant du même ordre que celui de carrière et, par ailleurs, de proposer une nouvelle conceptualisation de « carrière ». Cette contribution à propos du projet est illustrée par un exemple recueilli au cours de notre recherche. Des implications pour la pratique sont proposées.The notion of project is proposed as a relevant construct for the future of vocational psychology. Although used widely in a general sense, project has recently been used with specific meaning in vocational psychology. These meanings include its social and intentional nature, its extension in time, and its multidetermined and undeterminable characteristics. These uses are grounded in contextualist action theory. This conceptual grounding allows project to be used as a construct in the same order as career, and further facilitates a reconceptualization of career. The discussion of project is illustrated with a career-related example from our research. Implications for practice are suggested

    Seasonal trends in concentrations and fluxes of volatile organic compounds above central London

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    Concentrations and fluxes of seven volatile organic compounds (VOCs) were measured between August and December 2012 at a roof-top site in central London as part of the ClearfLo project (Clean Air for London). VOC concentrations were quantified using a proton transfer reaction-mass spectrometer and fluxes were calculated using a virtual disjunct eddy covariance technique. The median VOC fluxes, including aromatics, oxygenated compounds and isoprene, ranged from 0.07 to 0.33 mg m−2 h−1 and mixing ratios were 7.27 ppb for methanol (m / z 33) and <1 ppb for the remaining compounds. Strong relationships were observed between most VOC fluxes and concentrations with traffic density, but also with photosynthetically active radiation (PAR) and temperature for the oxygenated compounds and isoprene. An estimated 50–90 % of aromatic fluxes were attributable to traffic activity, which showed little seasonal variation, suggesting boundary layer effects or possibly advected pollution may be the primary causes of increased concentrations of aromatics in winter. PAR and temperature-dependent processes accounted for the majority of isoprene, methanol and acetaldehyde fluxes and concentrations in August and September, when fluxes and concentrations were largest. Modelled biogenic isoprene fluxes using the G95 algorithm agreed well with measured fluxes in August and September, due to urban vegetation. Comparisons of estimated annual benzene emissions from the London and National Atmospheric Emissions Inventory agreed well with measured benzene fluxes. Flux footprint analysis indicated emission sources were localized and that boundary layer dynamics and source strengths were responsible for temporal and spatial VOC flux and concentration variability during the measurement period

    The Challenge of Machine Learning in Space Weather Nowcasting and Forecasting

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    The numerous recent breakthroughs in machine learning (ML) make imperative to carefully ponder how the scientific community can benefit from a technology that, although not necessarily new, is today living its golden age. This Grand Challenge review paper is focused on the present and future role of machine learning in space weather. The purpose is twofold. On one hand, we will discuss previous works that use ML for space weather forecasting, focusing in particular on the few areas that have seen most activity: the forecasting of geomagnetic indices, of relativistic electrons at geosynchronous orbits, of solar flares occurrence, of coronal mass ejection propagation time, and of solar wind speed. On the other hand, this paper serves as a gentle introduction to the field of machine learning tailored to the space weather community and as a pointer to a number of open challenges that we believe the community should undertake in the next decade. The recurring themes throughout the review are the need to shift our forecasting paradigm to a probabilistic approach focused on the reliable assessment of uncertainties, and the combination of physics-based and machine learning approaches, known as gray-box.Comment: under revie

    Exploring Human Action in Counseling Psychology: The Action-Project Research Method

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    Qualitative research in counseling psychology in the last 2 decades has been characterized by the introduction and use of a range of methods and corresponding paradigms and conceptual frameworks. The action-project research method, described and updated in this article, is based on an understanding of human action as goal-directed and enacted in context: contextual action theory. We summarize this framework, prior to describing the method’s procedures for conceptualizing research problems and questions, collecting and analyzing data from dyads of participants, and presenting research findings. We also discuss recent adaptations to the procedures and how the method addresses core issues in counseling psychology; that is, methodological integrity, culture, ethics, and power. We proceed to describe how the method relates to other qualitative methods and the kinds of research questions asked by the discipline and how the action-project method connects to professional practice issues

    Canopy-scale flux measurements and bottom-up emission estimates of volatile organic compounds from a mixed oak and hornbeam forest in northern Italy

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    This paper reports the fluxes and mixing ratios of biogenically emitted volatile organic compounds (BVOCs) 4aEuro-m above a mixed oak and hornbeam forest in northern Italy. Fluxes of methanol, acetaldehyde, isoprene, methyl vinyl ketoneaEuro-+aEuro-methacrolein, methyl ethyl ketone and monoterpenes were obtained using both a proton-transfer-reaction mass spectrometer (PTR-MS) and a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) together with the methods of virtual disjunct eddy covariance (using PTR-MS) and eddy covariance (using PTR-ToF-MS). Isoprene was the dominant emitted compound with a mean daytime flux of 1.9aEuro-mgaEuro-m(-2)aEuro-h(-1). Mixing ratios, recorded 4aEuro-m above the canopy, were dominated by methanol with a mean value of 6.2aEuro-ppbv over the 28-day measurement period. Comparison of isoprene fluxes calculated using the PTR-MS and PTR-ToF-MS showed very good agreement while comparison of the monoterpene fluxes suggested a slight over estimation of the flux by the PTR-MS. A basal isoprene emission rate for the forest of 1.7aEuro-mgaEuro-m(-2)aEuro-h(-1) was calculated using the Model of Emissions of Gases and Aerosols from Nature (MEGAN) isoprene emission algorithms (Guenther et al., 2006). A detailed tree-species distribution map for the site enabled the leaf-level emission of isoprene and monoterpenes recorded using gas-chromatography mass spectrometry (GC-MS) to be scaled up to produce a bottom-up canopy-scale flux. This was compared with the top-down canopy-scale flux obtained by measurements. For monoterpenes, the two estimates were closely correlated and this correlation improved when the plant-species composition in the individual flux footprint was taken into account. However, the bottom-up approach significantly underestimated the isoprene flux, compared with the top-down measurements, suggesting that the leaf-level measurements were not representative of actual emission rates.Peer reviewe

    Outgoing Near‐Infrared Radiation From Vegetation Scales With Canopy Photosynthesis Across a Spectrum of Function, Structure, Physiological Capacity, and Weather

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    We test the relationship between canopy photosynthesis and reflected near-infrared radiation from vegetation across a range of functional (photosynthetic pathway and capacity) and structural conditions (leaf area index, fraction of green and dead leaves, canopy height, reproductive stage, and leaf angle inclination), weather conditions, and years using a network of field sites from across central California. We based our analysis on direct measurements of canopy photosynthesis, with eddy covariance, and measurements of reflected near-infrared and red radiation from vegetation, with light-emitting diode sensors. And we interpreted the observed relationships between photosynthesis and reflected near-infrared radiation using simulations based on the multilayer, biophysical model, CanVeg. Measurements of reflected near-infrared radiation were highly correlated with measurements of canopy photosynthesis on half-hourly, daily, seasonal, annual, and decadal time scales across the wide range of function and structure and weather conditions. Slopes of the regression between canopy photosynthesis and reflected near-infrared radiation were greatest for the fertilized and irrigated C4 corn crop, intermediate for the C3 tules on nutrient-rich organic soil and nitrogen fixing alfalfa, and least for the native annual grasslands and oak savanna on nutrient-poor, mineral soils. Reflected near-infrared radiation from vegetation has several advantages over other remotely sensed vegetation indices that are used to infer canopy photosynthesis; it does not saturate at high leaf area indices, it is insensitive to the presence of dead legacy vegetation, the sensors are inexpensive, and the reflectance signal is strong. Hence, information on reflected near-infrared radiation from vegetation may have utility in monitoring carbon assimilation in carbon sequestration projects or on microsatellites orbiting Earth for precision agriculture applications
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