2,464 research outputs found
Comparative Analysis of Harvesting and Silviculture Costs Following Integrated Harvesting
This paper presents a hypothetical case in which the positive and negative impacts of intensive forest harvesting (using the full tree method rather than the shortwood method) are evaluated over the long term using financial criteria. The full tree harvesting system collects branch and top material for use as a fuel as well as the roundwood. The analysis shows that the silviculture cost savings and energy biomass value more than offset the loss in long term value due to slower growth of the stand following intensive harvest. This conclusion is robust to changes in discount rate, value of roundwood and volume growth loss. The price of energy biomass had a major effect
Multimodal principal component analysis to identify major features of white matter structure and links to reading
The role of white matter in reading has been established by diffusion tensor imaging (DTI), but DTI cannot identify specific microstructural features driving these relationships. Neurite orientation dispersion and density imaging (NODDI), inhomogeneous magnetization transfer (ihMT) and multicomponent driven equilibrium single-pulse observation of T1/T2 (mcDESPOT) can be used to link more specific aspects of white matter microstructure and reading due to their sensitivity to axonal packing and fiber coherence (NODDI) and myelin (ihMT and mcDESPOT). We applied principal component analysis (PCA) to combine DTI, NODDI, ihMT and mcDESPOT measures (10 in total), identify major features of white matter structure, and link these features to both reading and age. Analysis was performed for nine reading-related tracts in 46 neurotypical 6–16 year olds. We identified three principal components (PCs) which explained 79.5% of variance in our dataset. PC1 probed tissue complexity, PC2 described myelin and axonal packing, while PC3 was related to axonal diameter. Mixed effects regression models did not identify any significant relationships between principal components and reading skill. Bayes factor analysis revealed that the absence of relationships was not due to low power. Increasing PC1 in the left arcuate fasciculus with age suggest increases in tissue complexity, while increases of PC2 in the bilateral arcuate, inferior longitudinal, inferior fronto-occipital fasciculi, and splenium suggest increases in myelin and axonal packing with age. Multimodal white matter imaging and PCA provide microstructurally informative, powerful principal components which can be used by future studies of development and cognition. Our findings suggest major features of white matter undergo development during childhood and adolescence, but changes are not linked to reading during this period in our typically-developing sample
Multinational Experiences in Reducing and Preventing the Use of Restraint and Seclusion
Restraint and seclusion (R/S) have been used in many countries and across service sectors for centuries. With the recent and increasing recognition of the harm associated with these procedures, efforts have been made to reduce and prevent R/S. Following a scathing media exposé in 1998 and congressional scrutiny, the United States began a national effort to reduce and prevent R/S use. With federal impetus and funding, an evidence-based practice, the Six Core Strategies1 to Prevent Conflict, Violence and the Use of Seclusion and Restraint, was developed. This model was widely and successfully implemented in a number of U.S. states and is being adopted by other countries, including Finland, Australia, and the United Kingdom. Recently, the first cluster randomized controlled study of the Six Core Strategies in Finland provided the first evidence-based data of the safety and effectiveness of a coercion prevention methodology. Preliminary findings of some of the international efforts are discussed. Reduction in R/S use and other positive outcomes are also reported
Technical Efficiency Evaluation of Logging Contractors Using a Nonparametric Model
Data Envelopment Analysis (DEA) models were used to measure the technical efficiency of a sample of logging contractors. DEA is a nonparametric efficiency measurement technique based on linear programming methods. This paper demonstrates how DEA models can be applied in a forest operations context to gain insights on the factors which affect technical efficiency and performance.
Twenty-three fully mechanized loggers were compared in regards to the efficiency with which they converted inputs – dollars of capital, consumables, and labor – into output – tons of wood. Overall, for the period of 1988 to 1994, the logging contractors studied were efficient, but some were considerably less efficient than others. Low capacity utilization had a negative impact on technical efficiency. The scale of an operation also influenced technical efficiency. For the sample, the most productive scale size was estimated to be around 75,000 tons per year
Childhood Memories of the Domestic Foodscape: The Home as a Site of Mindful Eating
This essay explores the home as an interactive built environment that dynamically stimulates and reflects food-related ideas and practice. The question we are asking is whether and how the architecture and design of the home can be conducive to “mindful eating,” a term defined here as having health-related implications but also as related to the creation of richly sensorial food-borne experiences encouraging communality and commensality. Our approach is a hybrid application of theory and methods derived from our respective domains of architecture and design studies, and marketing analysis: it analyzes the answers to a questionnaire that interrogates adult food behaviour, and also prompts the participants to document memories related to childhood eating experiences in the home. Our findings suggest that certain characteristics of domestic material culture do indeed anchor mindful eating practices, with the kitchen table having particular significance in this regard.
Résumé
Cet article envisage le foyer comme un environnement interactif qui exerce une influence dynamique sur les idées et les pratiques reliées à l’alimentation, tout en les reflétant. Nous cherchons à savoir si, et comment, l’architecture et la conception de la maison peuvent favoriser une « prise de conscience de l’alimentation », terme défini ici comme recouvrant à la fois des implications de santé, mais aussi d’expériences alimentaires de qualité sur le plan sensoriel, qui nourrissent le sentiment de communauté et de convivialité. Notre approche est hybride, consistant à appliquer des théories et des méthodes dérivées de nos champs d’études respectifs d’une part en architecture et en design, et d’autre part en analyses de marché : elle part des réponses à un questionnaire portant sur le comportement des adultes face à la nourriture, mais en enrichissant ces participants par des souvenirs liés aux expériences alimentaires de l’enfance à la maison. Nos découvertes suggèrent que certaines caractéristiques de la culture matérielle domestique contribuent de manière effective à ancrer des pratiques alimentaires conscientes, et que la table de la cuisine détient une signification particulière de ce point de vue
Enhancing multi-scale Mekong water governance
The CPWF Project PN50 “Enhancing multi-scale water governance” was a flagship activity
of the Mekong Program on Water, Environment Resilience (M-POWER). The goal of
helping improve livelihood security, human and ecosystem health in the Mekong Region
through democratizing water governance was pursued through critical research and
direct engagement with stakeholders involved in managing floods, irrigation,
hydropower, watersheds, fisheries and urban water works at various scales. We
identified commons governance problems and suggested ways that some can be
addressed. Often, for example, there are needs to: strengthen local representation,
improve the quality of deliberative processes, enhance the interplay between institutions
at different levels, and build capacities to handle uncertainties and adapt to changes in
flow regimes
Complémentarités et convergences de méthodes de régionalisation des précipitations : application à une région endoréique du Nord-Mexique
La connaissance des champs pluviométriques annuels est importante dans les zones arides et semi-arides où la gestion de l'eau est un exercice permanent d'aménagement de la pénurie, comme cela est le cas au Nord du Mexique.On se propose de montrer ici qu'une meilleure connaissance des disponibilités en eau peut s'appuyer sur la détermination de régions pluviométriquement homogènes à partir de diverses méthodes complémentaires ou convergentes.Pour définir des régions homogènes, on part de la répartition des stations par rapport à la régression pluviométrie/altitude. Des analyses factorielles en composantes principales et des correspondances permettent également de proposer des régions homogènes suivant des variables définies et disponibles pour toutes les stations. On s'appuie aussi sur les régimes pluviométriques pour déterminer d'autres régionalisations. Parallèlement on a pu utiliser la répartition des stations par rapport au gradient altitudinal pour créer des régions dont l'homogénéité vis-à -vis des précipitations a pu être vérifiée par la Méthode du Vecteur Régional (MVR), basée sur le principe de la pseudo-proportionnalité des données de postes proches.La comparaison des résultats obtenus par chacune des méthodes permet de constater que dans la région traitée, les limites entre régions " homogènes " sont souvent les mêmes, bien que les modes de détermination soient différents. Enfin, les différences apportent une information supplémentaire pour la compréhension des mécanismes locaux ou régionaux de la répartition des champs de pluie.Knowledge of annual rainfall is of great importance in arid and semi-arid areas, because water management is dominated by scarcity. The Nazas-Aguanaval river basin constitutes one of the main endoreic basins in Mexico (92 000 km2). It extends from the crests of the Western SierraMadre to as far as the Chihuahuan desert, in the states of Durango, Coahuila and Zacatecas. Spatial variability of rainfall is significant with annual rainfall amounts ranging from 900 mm in the higher areas of the Sierra Madre to 180 mm at the centre of the Laguna de Mayran. However, temporal variability of the precipitation amount is also appreciable, and it increases from the sub-humid areas of the mountains to the desert. The coefficient of variation for annual precipitation ranges from 0.2 in the mountains to 0.4 in Chihuahuan desert. Furthermore, in 1992, 1994, 1995, and from 1997 to 2000 severe rainfall deficits forced farmers to reduce strongly irrigated areas, thus leading to socio-economic development problems in this region. It is shown in this paper that an improvement in water availability knowledge is attainable by the determination of homogeneous rainfall regions, based on complementary or convergent methods.Rainfall distribution is a result of many factors, including the atmospheric circulation, the continental pattern, the coastal design, the location of major mountainous massifs, the distance from the ocean, and other site factors. The regionalisation of precipitation has been the subject of much research for almost all types of climates. The influence of zonal and regional factors is also determined in regional monographs where the role of local variables (relief, vegetation, general roughness of landscape, etc.) is described in relation to the large-scale circulation scheme. In most of the cases, the interpolation of values between two observations is necessary and quite difficult. Kriging is widely used for this purpose, as is co-kriging, which takes into account the topography or some other local factors and frequently gives better reconstitution of rainfall data. In order to determine the first set of homogeneous regions in northwestern Mexico, the elevation gradient of the rainfall amount was defined by a simple regression. All the stations were located with respect to the regression line and they can form apparent groups. The following relation was obtained :P=0.31 H - 133r2=0.73; n=84)(where P is annual rainfall in mm and H the altitude in m).In the same way, various statistical analysis were performed using all data available from the rainfall measurement stations, such as elevation, distance from the Pacific Ocean, exposure, annual rainfall amount, and the type of topography and vegetation cover surrounding the station. An Empirical Orthogonal Function Analysis (EOF) and a Factorial Analysis of Correspondences (FAC) revealed other kinds of regionalisation. The precipitation regime is tropical-like in spite of the latitude (25° N), but the percentage of annual precipitation in winter appeared as a segregating factor and thus was used to define the climatic geography. This was determined by a stepwise discriminant analysis, which allowed the segregation of the north-eastern area of the Nazas-Aguanaval basin. This is the dryer region of the basin because it is less exposed to monsoon fluxes and the proportion of winter rain is higher there than in the remaining basin.The main variables explaining the spatial distribution of precipitation are altitude and distance from the Pacific Ocean, as determined by both the EOF analysis and the analysis of correspondences. The grouping of stations segregated by the elevation gradient regression led to regions where the homogeneity in relation to the annual rainfall amount was tested and verified by the Regional Vector Method (RVM). This method is based on the principle of pseudo-proportionality between annual rainfall amounts at close stations.The Nazas-Aguanaval basin is divided into three climatic regions defined by precipitation: the Western Sierra Madre, the Chihuahuan desert, and a semi-arid area that is divided into two sub-regions (Middle Nazas basin and Aguanaval plateau) by the analysis of correspondences. As a result of the regional rainfall analysis, some variograms were performed to determine the length of the validity of the rainfall data. However, it appeared that a multidirectional variogram did not explain these data. The role that relief (mainly the Western Sierra Madre) plays in the spatial distribution of precipitation does not explain the length of rainfall data. Introducing the direction of mountain range into the variogram demonstrated that the relief played a significant role, and in this case the length of the rainfall variogram data was 180 km.A comparison of results obtained using each method led to the conclusion that the boundaries between homogeneous regions are often the same while the determination processes are different. Finally, all the proposed methods are complementary and the differences between all characterisations give additional information regarding the local and regional processes that explain the annual rainfall spatial distribution. Simple tools have been used to acquire a better knowledge of rainfall spatial distribution.In the case of Northern Mexico, the low density of a measurement network (rain gauges), particularly in mountainous or arid zones, is partially attenuated by the possibility of evaluating the main climatic characteristics for the different regions defined in terms of rainfall
STUDY OF THE TRANSLOCATION OF PLUTONIUM AND AMERICIUM FROM PUNCTURE WOUNDS. Summary Report, April 1, 1968--June 15, 1971.
Improving Mekong water resources investment and allocation choices
The CPWF Project PN67 “Improving Mekong Water Allocation” was a key, collaborative
activity of the Mekong Program on Water, Environment and Resilience (M-POWER). The
goal of contributing to water allocation policy and practice which results in a more
optimal and equitable use of water by society has been pursued by research across the
Mekong Region and active engagement with policymakers. The project team have
examined the use of a wide range of decision-support tools, in many decision-making
arenas. In doing so, they have sought to understand decision contexts and drivers
Parlons sciences ensemble : la place du dialogue dans l’enseignement des sciences au secondaire en contexte minoritaire
Cette communication propose de caractériser la place de l’oral, et plus précisément du dialogue, dans des cours de sciences dans une école secondaire de langue française en milieu francophone minoritaire. Les résultats découlent d’une recherche collaborative entreprise avec trois enseignants de sciences chevronnés qui cherchaient à mieux comprendre le rôle et le potentiel du dialogue exploratoire dans leur enseignement. Les activités analysées par l’équipe révèlent une variété de postures empruntées par les élèves et l’enseignant selon le type d’activité, le but de l’activité et l’ergonomie de la salle de classe. Une discussion sur la place (et l’absence) du dialogue exploratoire et des pistes pour favoriser son utilisation contribue au répertoire d’approches pédagogiques adaptées au milieu minoritaire francophone canadien dans le domaine de l’enseignement des sciences
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