514 research outputs found
Psychologie phĂ©nomĂ©nologique de la rĂ©ciprocitĂ© : dynamique de l'ĂȘtre-ensemble pour la performation de l'agressivitĂ© humaine et sportive
The present social division urges to think about humans's competence to live side by side on a peace common world. We assert that an intersubjective psychic process that would operate in intersubjectivity's relationship: human being and being together are created by a dynamics of mutual recognition of consciousnesses (reciprocity phenomenon). âReference figure» initiate that. This thesis was put to the test in the field of sport. The first study showed that an authentic self-sacrifice by the reference figure, being-next-to, keeps safe from being-together. A second study showed that a consciousness of intersubjectivity of the reference figure allows a start of the reciprocity movement. Finally, a research-action into sportive-mediated workshop showed how a fight for recognition, if the reference figure is âatmospherically goodâ and is recognized as such, shows how the primitive aggressiveness of a young delinquent perform towards a mutuality of consciousnesses by a oneself-common world âs unity creation. All the results allow to conclude that the reciprocity phenomenon releases a passive physical phenomenon (reception) together with an active physical phenomenon (giving, for-giveness).La division sociale actuelle pousse Ă rĂ©flĂ©chir sur la capacitĂ© d'un individu Ă vivre avec autrui dans un monde commun pacifiĂ©. Nous soutenons qu'un processus prĂ©-psychique est Ă l'Ćuvre au sein de la relation intersubjective : l'ĂȘtre-soi et l'ĂȘtre-ensemble se crĂ©ent par la dynamique de reconnaissance mutuelle des consciences (le phĂ©nomĂšne de rĂ©ciprocitĂ©). La « figure de rĂ©fĂ©rence » en est l'initiateur. Cette thĂšse a Ă©tĂ© mise Ă l'Ă©preuve dans le champ du sport. La premiĂšre sĂ©rie d'Ă©tudes a montrĂ© que le don de soi authentique de la figure de rĂ©fĂ©rence, l'ĂȘtre-auprĂšs-de, prĂ©serve l'ĂȘtre-ensemble. Une deuxiĂšme sĂ©rie d'Ă©tudes a montrĂ© que la conscience d'intersubjectivitĂ© de la figure de rĂ©fĂ©rence permet d'amorcer le mouvement de rĂ©ciprocitĂ©. Enfin, une recherche-action dans un atelier Ă mĂ©diation sportive a montrĂ© comment la lutte pour la reconnaissance, si la figure de rĂ©fĂ©rence est « atmosphĂ©riquement bonne » et reconnue comme telle, performe l'agressivitĂ© primitive d'un jeune dĂ©linquant vers la mutualitĂ© des consciences, par la crĂ©ation d'une unitĂ© soi-monde. L'ensemble des rĂ©sultats permet de conclure que le phĂ©nomĂšne de la rĂ©ciprocitĂ© dĂ©gage en mĂȘme temps un phĂ©nomĂšne corporel passif (la rĂ©ception) et un phĂ©nomĂšne corporel actif (le don et le par-don)
There is room for everyone: Invasion credit cannot be inferred from the speciesâarea relationship in fragmented forests
Questions: Land use change, habitat fragmentation and biological invasion represent major drivers of global change that strongly interact to alter ecosystems. Following the breaking apart of forests into smaller fragments or the afforestation of former agricultural lands, biodiversity experiences drastic changes due to species loss and turnover over time. This leads to two important outcomes, namely extinction debt and invasion (colonization) credit, which both reflect the inertia of the system's response to environmental changes. Our study investigated the following questions: Is it possible to infer invasion credit from speciesâarea relationship (SAR) residuals both for native and alien plants? Is there any trend linked with the degree of habitat fragmentation through time?. Location: Somme, Oise and Aisne departments, northern France. Methods: We analyzed the pattern of SARs' residuals for native and alien vascular plant species separately across nine sets of forest fragments that differ by the landscape matrix they are embedded in (i.e., open field, bocage, forest), while considering plant richness, area and age of the 355 forest patches. Results: The relationship between alien and native SARsâ residuals is positive across all landscapes, suggesting a lack of invasion credit. Instead, these results support the ârich get richerâ hypothesis, that is a high environmental heterogeneity allows colonization by new species, be they native or alien. Interestingly, the relationship between alien and native residuals depends upon fragment age (i.e., time since patch creation) in the most intensively managed landscapes (i.e., open fields). In the latter, recent forest patches are more prone to alien invasion, as a likely consequence of increased alien propagule pressure (i.e., more sources and vectors for alien plants), increased forest invasibility (i.e., disturbance-induced environmental heterogeneity), and decreased matrix permeability (i.e., natives are more dispersal-limited than aliens). Conclusions: Our study provides new insights into alien species ecology, by showing that (i) it is not possible to infer âinvasion creditâ from the SAR's residuals; (ii) the invasion rate by alien species in forest fragments increases with their native species richness, and (iii) this relationship depends upon patch age in intensively managed landscapes
There is room for everyone: Invasion credit cannot be inferred from the speciesâarea relationship in fragmented forests
Questions
Land use change, habitat fragmentation and biological invasion represent major drivers of global change that strongly interact to alter ecosystems. Following the breaking apart of forests into smaller fragments or the afforestation of former agricultural lands, biodiversity experiences drastic changes due to species loss and turnover over time. This leads to two important outcomes, namely extinction debt and invasion (colonization) credit, which both reflect the inertia of the system's response to environmental changes. Our study investigated the following questions:
Is it possible to infer invasion credit from speciesâarea relationship (SAR) residuals both for native and alien plants?
Is there any trend linked with the degree of habitat fragmentation through time?
Location
Somme, Oise and Aisne departments, northern France.
Methods
We analyzed the pattern of SARs' residuals for native and alien vascular plant species separately across nine sets of forest fragments that differ by the landscape matrix they are embedded in (i.e., open field, bocage, forest), while considering plant richness, area and age of the 355 forest patches.
Results
The relationship between alien and native SARsâ residuals is positive across all landscapes, suggesting a lack of invasion credit. Instead, these results support the ârich get richerâ hypothesis, that is a high environmental heterogeneity allows colonization by new species, be they native or alien. Interestingly, the relationship between alien and native residuals depends upon fragment age (i.e., time since patch creation) in the most intensively managed landscapes (i.e., open fields). In the latter, recent forest patches are more prone to alien invasion, as a likely consequence of increased alien propagule pressure (i.e., more sources and vectors for alien plants), increased forest invasibility (i.e., disturbance-induced environmental heterogeneity), and decreased matrix permeability (i.e., natives are more dispersal-limited than aliens).
Conclusions
Our study provides new insights into alien species ecology, by showing that (i) it is not possible to infer âinvasion creditâ from the SAR's residuals; (ii) the invasion rate by alien species in forest fragments increases with their native species richness, and (iii) this relationship depends upon patch age in intensively managed landscapes
Biotic and abiotic drivers of intraspecific trait variation within plant populations of three herbaceous plant species along a latitudinal gradient
Background: The importance of intraspecific trait variation (ITV) is increasingly acknowledged among plant ecologists. However, our understanding of what drives ITV between individual plants (ITVBI) at the population level is still limited. Contrasting theoretical hypotheses state that ITVBI can be either suppressed (stress-reduced plasticity hypothesis) or enhanced (stress-induced variability hypothesis) under high abiotic stress. Similarly, other hypotheses predict either suppressed (niche packing hypothesis) or enhanced ITVBI (individual variation hypothesis) under high niche packing in species rich communities. In this study we assess the relative effects of both abiotic and biotic niche effects on ITVBI of four functional traits (leaf area, specific leaf area, plant height and seed mass), for three herbaceous plant species across a 2300 km long gradient in Europe. The study species were the slow colonizing Anemone nemorosa, a species with intermediate colonization rates, Milium effusum, and the fast colonizing, non-native Impatiens glandulifera.
Results: Climatic stress consistently increased ITVBI across species and traits. Soil nutrient stress, on the other hand, reduced ITVBI for A. nemorosa and I. glandulifera, but had a reversed effect for M. effusum. We furthermore observed a reversed effect of high niche packing on ITVBI for the fast colonizing non-native I. glandulifera (increased ITVBI), as compared to the slow colonizing native A. nemorosa and M. effusum (reduced ITVBI). Additionally, ITVBI in the fast colonizing species tended to be highest for the vegetative traits plant height and leaf area, but lowest for the measured generative trait seed mass.
Conclusions: This study shows that stress can both reduce and increase ITVBI, seemingly supporting both the stress-reduced plasticity and stress-induced variability hypotheses. Similarly, niche packing effects on ITVBI supported both the niche packing hypothesis and the individual variation hypothesis. These results clearly illustrates the importance of simultaneously evaluating both abiotic and biotic factors on ITVBI. This study adds to the growing realization that within-population trait variation should not be ignored and can provide valuable ecological insights
The effects of stand characteristics on the understory vegetation in Quercus petraea and Q. cerris dominated forests
The shelterwood system used in Hungary has many effects on the composition and structure of the herb layer. The aim of our study was to identify the main variables that affect the occurence of herbs and seedlings in Turkey oak-sessile oak (Quercus cerris and Q. petraea) stands. The study was carried out in the BĂŒkk mountains, Hungary. 122 sampling plots were established in 50-150 year old oak forests, where we studied the species composition and structure of the understorey and overstorey. The occurence of herbs was affected by canopy closure, the heterogenity and patchiness of the stand, the slope and the east-west component of the aspect. The composition of saplings was significantly explained by the ratio of the two major oak species in the stand and the proximity of the adult plants. An important result for forest management was that sessile oaks were able to regenerate almost only where they were dominant in the overstorey
Hedging against biodiversity loss : forest herbsâ performance in hedgerows across temperate Europe
Questions: How do contrasting environmental conditions among forests and hedgerows affect the vegetative and reproductive performance of understorey forest herbs in both habitats? Can hedgerows support reproductive source populations of forest herbs, thus potentially allowing progressive dispersal of successive generations along these linear habitats?
Location: Hedgerows and deciduous forest patches in agricultural landscapes across the European temperate biome.
Methods: First, we assessed differences in environmental conditions among forests and hedgerows. Next, we quantified plant performance based on a set of functional lifeâhistory traits for four forest herbs (Anemone nemorosa, Ficaria verna, Geum urbanum, Poa nemoralis) with contrasting flowering phenology and colonisation capacity in paired combinations of forests and hedgerows, and compared these traits among both habitats. Finally, we assessed relationships between plant performance and environmental conditions in both habitats.
Results: All study species showed a higher aboveâground biomass in hedgerows than in forests. For Poa nemoralis and Geum urbanum, we also found a higher reproductive output in hedgerows, which was mainly correlated to the higher subâcanopy temperatures therein. The âancient forest herbâ Anemone nemorosa, however, appeared to have a lower reproductive output in hedgerows than in forests, while for Ficaria verna no reproductive differences were found between the two habitats.
Conclusions: This is the first study on such a broad geographical scale to provide evidence of reproductive source populations of forest herbs in hedgerows. Our findings provide key information on strategies by which forest plants grow, reproduce and disperse in hedgerow environments, which is imperative to better understand the dispersal corridor function of these wooded linear structures. Finally, we highlight the urgent need to develop guidelines for preserving, managing and establishing hedgerows in intensive agricultural landscapes, given their potential to contribute to the longâterm conservation and migration of forest herbs in the face of global environmental change
Acute Pancreatitis due to pH-Dependent Mesalazine That Occurred in the Course of Ulcerative Colitis
We report the case of a 26-year-old male who presented with acute pancreatitis during the course of treatment for pancolitic ulcerative colitis (UC) with a time-dependent mesalazine formulation, prednisolone and azathioprine (AZA). Despite a review of his clinical history and various tests, the cause of pancreatitis could not be determined. Since drug-induced pancreatitis was considered possible, administration of the time-dependent mesalazine preparation and AZA was discontinued, and conservative treatment for acute pancreatitis was performed. The pancreatitis promptly improved with these treatments, but drug lymphocyte stimulation test (DLST) for both the time-dependent mesalazine formulation and AZA was negative. A pH-dependent mesalazine formulation was given for maintenance therapy of UC. Subsequently, as the pancreatitis relapsed, drug-induced pancreatitis was strongly suspected. Administration of mesalazine was discontinued, and pancreatitis was smoothly in remission by conservative treatment. According to the positive DLST result for the pH-dependent mesalazine formulation and the clinical course, a diagnosis of pH-dependent mesalazine-induced pancreatitis due to this formulation was made. During the clinical course of UC, occurrence of drug-induced pancreatitis must always be considered
Sensitivity to habitat fragmentation across European landscapes in three temperate forest herbs
Context Evidence for effects of habitat loss and fragmentation on the viability of temperate forest herb populations in agricultural landscapes is so far based on population genetic studies of single species in single landscapes. However, forest herbs differ in their life histories, and landscapes have different environments, structures and histories, making generalizations difficult. Objectives We compare the response of three slow-colonizing forest herbs to habitat loss and fragmentation and set this in relation to differences in life-history traits, in particular their mating system and associated pollinators. Methods We analysed the herbs' landscape-scale population genetic structure based on microsatellite markers from replicate forest fragments across seven European agricultural landscapes. Results All species responded to reductions in population size with a decrease in allelic richness and an increase in genetic differentiation among populations. Genetic differentiation also increased with enhanced spatial isolation. In addition, each species showed unique responses. Heterozygosity in the self-compatible Oxalis acetosella was reduced in smaller populations. The genetic diversity of Anemone nemorosa, whose main pollinators are less mobile, decreased with increasing spatial isolation, but not that of the bumblebee-pollinated Polygonatum multiflorum. Conclusions Our study indicates that habitat loss and fragmentation compromise the long-term viability of slow-colonizing forest herbs despite their ability to persist for many decades by clonal propagation. The distinct responses of the three species studied within the same landscapes confirm the need of multi-species approaches. The mobility of associated pollinators should be considered an important determinant of forest herbs' sensitivity to habitat loss and fragmentation
Strength of forest edge effects on litter-dwelling macro-arthropods across Europe is influenced by forest age and edge properties
International audienceAim: Forests are highly fragmented across Western Europe, making forest edges im âportant features in many agricultural landscapes. Forest edges are subject to strong abiotic gradients altering the forest environment and resulting in strong biotic gradi âents. This has the potential to change the forest's capacity to provide multiple eco âsystem services such as nutrient cycling, carbon sequestration and natural pest control. Soil organisms play a key role in this perspective; however, these taxa are rarely considered in forest edge research.Location: A latitudinal gradient of 2,000 km across Western Europe.Methods: We sampled six dominant taxa of litterâdwelling macroâarthropods (car âabid beetles, spiders, harvestmen, centipedes, millipedes and woodlice) in forest edges and interiors of 192 forest fragments in 12 agricultural landscapes. We related their abundance and community composition to distance from the edge and the inter âaction with forest age, edge orientation and edge contrast (contrast between land use types at either side of the edge).Results: Three out of six macroâarthropod taxa have higher activityâdensity in forest edges compared to forest interiors. The abundance patterns along forest edgeâtoâinâterior gradients interacted with forest age. Forest age and edge orientation also influ âenced withinâfragment compositional variation along the forest edgeâtoâinterior gradient. Edge contrast influenced abundance gradients of generalist predators. In general, older forest fragments, southâoriented edges and edges along structurally more continuous land use (lower contrast between forest and adjacent land use) re âsulted in stronger edgeâtoâinterior gradients while recent forests, northâoriented edges and sharp land use edges induced similarity between forest edge and interior along the forest edgeâtoâinterior gradients in terms of species activityâdensity and composition.Main conclusions: Edge effects on litterâdwelling macroâarthropods are anticipated to feedback on important ecosystem services such as nutrient cycling, carbon se âquestration and natural pest control from small forest fragments
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