Addressing the Impact of Atmospheric Nitrogen Deposition on Western European Grasslands.

There is a growing evidence base demonstrating that atmospheric nitrogen deposition presents a threat to biodiversity and ecosystem function in acid grasslands in Western Europe. Here, we report the findings of a workshop held for European policy makers to assess the perceived importance of reactive nitrogen deposition for grassland conservation, identify areas for policy development in Europe and assess the potential for managing and mitigating the impacts of nitrogen deposition. The importance of nitrogen as a pollutant is already recognized in European legislation, but there is little emphasis in policy on the evaluation of changes in biodiversity due to nitrogen. We assess the potential value of using typical species, as defined in the European Union Habitats Directive, for determining the impact of nitrogen deposition on acid grasslands. Although some species could potentially be used as indicators of nitrogen deposition, many of the typical species do not respond strongly to nitrogen deposition and are unlikely to be useful for identifying impact on an individual site. We also discuss potential mitigation measures and novel ways in which emissions from agriculture could be reduced.

Turbidity and nitrate transfer in karstic aquifers in rural areas: the Brionne Basin case-study.

The degradation of water quality in many groundwaters of Europe is a major source of concern. Rises in turbidity and nitrate concentrations represent present or potential threats for the quality of drinking water in rural areas. They are for the most part a consequence of agricultural intensification which has considerably affected land cover and land use in recent decades. In our case-study (a karstic catchment) the mechanisms which explain changes in water quality, as far as turbidity and nitrate are concerned, result from a strong continuity between surface and underground waters. The karstic system of the Brionne Basin can be considered as both the focus of rapid horizontal flows (runoff, a rapid process in which rainwater reaches the spring directly through sinkholes) and slow vertical flows (leaching, in which rainwater filters through the soil to the spring). A hierarchical approach to the water pollution problem of the basin suggests that turbidity or nitrate concentrations peak during heavy rain episodes and are short-term events. In terms of management, this implies that the solution to water pollution caused by such events is also short-term and can therefore be addressed at a local scale. The rise of nitrate concentrations during the past twenty years is the main concern. The solution can only be found at a global scale (all the catchment area must be taken in account: land plots and their spatial configuration), and by taking a long-term approach.

[Prospective research on the duality between morphological traits and plant competitive capacity: the case of weed species and wheat]. / Recherche prospective sur la dualité entre caractéristiques morphologiques et capacités de compétition des végétaux: le cas des espèces adventices et du blé.

Competitive abilities of plants were interpreted by measuring their morphological traits in interspecific competitive cultivation conditions. Measurements were realised by a comparative approach with interspecific cultivation of fourteen arable weeds growing with a domestic species cultivated at a large scale: the winter wheat (Triticum aestivum var Darius). Results show that arable weeds characterised by an important biomass and allocation of biomass to the stems are responsible for a decrease in wheat biomass, and for the ear, a decrease in height, biomass and number of seeds. These results are discussed in view of predicting competitive abilities of arable weeds with a simple method and for the conservation of arable weeds since some of them are among the most threatened species of the European flora.

Pulmonary disease associated with the human immunodeficiency virus in Kigali, Rwanda. A fiberoptic bronchoscopic study of 111 cases of undetermined etiology.

All human immunodeficiency virus type 1 (HIV-1) infected adult patients referred to the Division of Pulmonary Diseases of the Centre Hospitalier de Kigali, Rwanda for evaluation of a pulmonary disease of undetermined etiology (PDUE) were investigated by fiberoptic bronchoscopy using both bronchoalveolar lavage (BAL) and transbronchial biopsy (TBB). During a 10-mo period 111 HIV-1 infected patients with PDUE were examined, of whom 47 (42%) fulfilled the World Health Organization (WHO) clinical case definition for acquired immunodeficiency syndrome (AIDS) and seven (6%) had an AIDS-defining illness. Nonspecific interstitial pneumonitis was diagnosed in 42 (38%) patients, tuberculosis in 25 (23%), cryptococcosis in 14 (13%), Kaposi's sarcoma (KS) in 10 (9%), Pneumocystis carinii pneumonia (PCP) in five (5%). The diagnosis remained undetermined in 18 (16%) patients. Chest radiograph patterns were generally nonspecific. TBB and BAL had diagnostic yields of 82 and 26% of all final diagnoses, respectively. Our study on Rwandese HIV-1-infected patients with PDUE provides evidence for a large spectrum of pulmonary diseases with relative frequencies differing strikingly from those in developed countries. Detailed investigations confirm the rarity of PCP in Africa and highlight nonspecific interstitial pneumonitis as the predominant diagnosis of PDUE. Empiric antituberculosis treatment is justified in the absence of clinical manifestations suggestive of a specific diagnosis and while awaiting the results of the diagnostic procedures. Primary prophylaxis for PCP would not be appropriate in Africa.