133 research outputs found

    IMMUNOLOGIC CHANGES OF PATIENTS WITH ACTIVE PULMONARY TUBERCULOSIS AFTER TUBERCULIN PROVOCATION

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    CARDIOVASCULAR DISORDERS IN EARLY FORMS OF CHRONIC RESPIRATORY FAILURE

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    PLASMA GROWTH HORMONE LEVEL AND HYPERTROPHIC OSTEOARTHROPATHY IN PATIENTS WITH CARCINOMA

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    3D SPATIAL OPERATIONS FOR GEO-DBMS: GEOMETRY VS. TOPOLOGY

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    Geo-DBMS becomes very important medium for GIS as it can handle and manage (e.g. retrieve and update) large volume of spatial data. Providing 3D spatial database with appropriate operation tools such as 3D spatial operations would be very useful for next generation of GIS software (i.e. 3D GIS) since the software would highly depend on the Geo-DBMS in both modeling and analysis. One of the desired components in such future software or system is geometric modeling capability that works with 3D spatial operations. The literature reveals 3D spatial database would be greatly enhanced if analytical operations on the spatial data could be manipulated in real 3D domain. Fundamentally, it can be considered that the aspect of 3D spatial operations within GIS software are still not much been addressed and solved as expected (i.e. up to the level where an operational 3D system could be realized). The main problem from this aspect is the unavailability of 3D spatial data type within geo-DBMS environment. It is the aim of this paper to describe 3D spatial operations for geometrical and topological data types within geo-DBMS environment. In the experiment, we utilize an existing geo-DBMS, PostgreSQL, later known as PostGIS, which complied with the standard specifications from Open Geospatial Consortium (OGC), e.g. abstract and geometry specification. The second factor why we utilise the PostGIS is because its an open source based technology and suitable for academic and research purposes. In this paper, we discuss a suitable way of developing a new 3D data type, polyhedron, for both geometrical and topological data types and spatial operations using C language. 1

    Large-scale atmospheric circulation enhances the Mediterranean East-West tree growth contrast at rear-edge deciduous forests

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    Overlaid to a general reduction of European beech and sessile oak tree growth over the recent decades in the Mediterranean Basin, tree-ring records from western Mediterranean populations display a stronger growth decrease than eastern populations. We investigate here to what extent the impact of sustained atmospheric circulation patterns in summertime can explain the observed spatial patterns of tree growth. We use Canonical Correlation Analysis, a statistical method that identifies the coupled patterns that are optimally correlated between two multivariate data sets. A general change in growth trends, shifting from a general increase during the period 1950\ue2\u80\u931981 to a decrease during the last three decades (1982\ue2\u80\u932012), can be attributed to increasing summer temperatures, which exert a dominant and negative influence on growth in both tree species across sites. However, summer precipitation has gained importance for growth, coinciding with the intensification of the geographical polarity in climate conditions across the Mediterranean Basin. This intensification during the last three decades can be traced back to a strengthening of the Summer North Atlantic Oscillation (SNAO), which imparts an east-west dipole to summer climate in this region. Under predicted persistent stronger SNAO in the future, western populations would face harsher summer conditions than central and eastern rear-edge populations, due to decreasing precipitation and increasing temperatures in the western Mediterranean Basin. These results evidence the determinant role that changes in the atmospheric circulation patterns may play in the persistence of rear-edge temperate deciduous forests in the near future

    Evolution-based approach needed for the conservation and silviculture of peripheral forest tree populations

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    The fate of peripheral forest tree populations is of particular interest in the context of climate change. These populations may concurrently be those where the most significant evolutionary changes will occur; those most facing increasing extinction risk; the source of migrants for the colonization of new areas at leading edges; or the source of genetic novelty for reinforcing standing genetic variation in various parts of the range. Deciding which strategy to implement for conserving and sustainably using the genetic resources of peripheral forest tree populations is a challenge. Here, we review the genetic and ecological processes acting on different types of peripheral populations and indicate why these processes may be of general interest for adapting forests and forest management to climate change. We particularly focus on peripheral populations at the rear edge of species distributions where environmental challenges are or will become most acute. We argue that peripheral forest tree populations are “natural laboratories” for resolving priority research questions such as how the complex interaction between demographic processes and natural selection shape local adaptation; and whether genetic adaptation will be sufficient to allow the long-term persistence of species within their current distribution. Peripheral populations are key assets for adaptive forestry which need specific measures for their preservation. The traditionally opposing views which may exist between conservation planning and sustainable forestry need to be reconciled and harmonized for managing peripheral populations. Based on existing knowledge, we suggest approaches and principles which may be used for the management and conservation of these distinctive and valuable populations, to maintain active genetic and ecological processes that have sustained them over time
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