Search results for "River"
showing 10 items of 564 documents
The effect of buffer strip width and selective logging on streamside plant communities
2019
Background Riparian forests surrounding streams host high biodiversity values, but are threatened by clear-cut logging. Narrow buffer strips of about 15 m are commonly left between the stream and the clear-cut, but studies suggest that the buffer width should be at least 30 m to protect riparian plant communities. Moreover, selective logging is often allowed on the buffer strips in order to increase economic gain. We used an experiment of 43 riparian sites where buffer strip width and selective logging within the strip were manipulated and supplemented with unlogged control sites. We report the short-term changes in the community composition of vascular plants and mosses near the stream (0–…
Are there so many congeneric species of chironomid larvae in a small stream?
2018
The co-occurrence of larvae of congeneric chironomid species is common in natural stream assemblages, and raises the problem of finding mechanisms to explain the co-existence of species with similar ecological requirements. In this contribution, we explored the co-occurrence of chironomid larvae belonging to congeneric species within four genera of chironomids: Cricotopus, Eukiefferiella, Orthocladius and Rheocricotopus (with 2, 7, 2 and 4 species, respectively) in the headwaters of a small Mediterranean calcareous stream. Due to the intrinsic, natural spatial and temporal variability in these habitats, we studied three different sites at two different seasons within the annual hydrological…
la prospection systématique d’un fond de rivière : l’exemple du Doubs
2020
La présentation des méthodes mises en œuvre et des résultats obtenus à l’occasion d’une opération de prospection subaquatique systématique menée sur la rivière Doubs, en amont de Verdun-sur-le-Doubs (Saône-et-Loire), illustre en grandeur réelle l’intérêt de la démarche adoptée, fondée sur des principes simples, dans la perspective d’un inventaire systématique du patrimoine fluvial immergé. La diversité des vestiges découverts et leur répartition sur la longue durée en soulignent la pertinence mais également, s’il en était encore besoin, la réalité du formidable potentiel archéologique que recèlent les cours d’eau. The presentation of the methods used and results obtained during a systematic…
Short sea migration and precocious maturation in reared Atlantic salmon post-smolts in the northern Baltic Sea
2017
Abstract Atlantic salmon (Salmo salar L.) display significant variation in life history traits, including migration patterns and age at maturity. Hatchery rearing has been shown to affect the life history, and rearing-induced changes may include unfavourable consequences, e.g. shortened sea migration period and smaller size at maturity. We report on a new phenomenon of life history of reared Atlantic salmon in the Baltic Sea area: small-sized salmon returning to freshwater only a few months after release as smolts. These “one-sea-summer (1SS)” salmon were ca. 35 cm in length and weighed ca. 400 g, being clearly larger than smolts, but substantially smaller than one-sea-winter (1SW) salmon f…
River processes and Links between fluvial and coastal systems in a changing climate
2018
It is well known that a changing climate leads to changes in the frequency, intensity, spatial extent, duration, and timing of extreme weather and climate events. Models indicate substantial warming in temperature extremes by the end of the 21st century (IPCC, 2012). The global warming determines several environmental problems altering the hydrologic cycle, with changes to the amount, timing, and intensity of precipitation (see as an example Rahimpour Golroudbary et al., 2016), and impacting on the soil erosion rate and on the quality of aquatic and marine environments (see as an example Robins et al., 2016). The present Special Issue collects main contributions arising from the aforementio…
Genetic and Epigenetic Characteristics of Inflammatory Bowel Disease-Associated Colorectal Cancer.
2021
doi: 10.1053/j.gastro.2021.04.042 Background & Aims Inflammatory bowel disease (IBD) is a chronic, relapsing inflammatory disorder associated with an elevated risk of colorectal cancer (CRC). IBD-associated CRC (IBD-CRC) may represent a distinct pathway of tumorigenesis compared to sporadic CRC (sCRC). Our aim was to comprehensively characterize IBD-associated tumorigenesis integrating multiple high-throughput approaches, and to compare the results with in-house data sets from sCRCs. Methods Whole-genome sequencing, single nucleotide polymorphism arrays, RNA sequencing, genome-wide methylation analysis, and immunohistochemistry were performed using fresh-frozen and formalin-fixed tissue sam…
High food quality increases infection of Gammarus pulex (Crustacea: Amphipoda) by the acanthocephalan parasite Pomphorhynchus laevis.
2019
13 pages; International audience; Parasitism is an important process in ecosystems, but has been largely neglected in ecosystem research. However, parasites are involved in most trophic links in food webs with, in turn, a major role in community structure and ecosystem processes. Several studies have shown that higher nutrient availability in ecosystems tends to increase the prevalence of parasites. Yet, most of these studies focused on resource availability, whereas studies investigating resource quality remain scarce. In this study, we tested the impact of the quality of host food resources on infection by parasites, as well as on the consequences for the host. Three resources were used t…
Cryptosporidiosis Outbreak in Immunocompetent Children from a Remote Area of French Guiana: CRYPTOSPORIDIOSIS OUTBREAK IN AMAZONIAN CHILDREN
2018
International audience; In September 2014, an increase in the number of Cryptosporidium spp. gastrointestinal tract infections was reported over a 6-month period among children living in a remote area along the Maroni River in French Guiana. Children presented gastroenteritis symptoms with Cryptosporidium-positive stools. Questionnaires were administered and stool examinations were controlled 3 months after the onset of symptoms. Data collection included demographics, food consumption, river behavior, symptoms, and outcome. Stool specimens were tested using microscopy and polymerase chain reaction. Samples from the water systems were examined for turbidity and culture for bacteria. Data fro…
Immuno-targeted combinations in oncogene-addicted non-small cell lung cancer
2018
The identification of tumor “oncogenic drivers” and the subsequent development of targeted therapy represented a milestone in the treatment of lung cancer over the last years. Tumor genotyping has been incorporated into therapeutic decision making of advanced non-small cell lung cancer (NSCLC) since has become clear that individuals with actionable molecular alterations receiving a matched targeted agent certainly live longer and better. The recent understanding of biological mechanisms underlying cancer immune evasion has allowed the development of a new class of immunomodulatory agents which are able to reactivate host immune-response, offering the potential for long-term disease control …
External Influences on Invertebrate Brain Histamine and Related Compounds via an Automated Derivatization Method for Capillary Electrophoresis.
2017
8 pages; International audience; Histamine has been shown to modulate visual system and photic behavior in arthropods. However, few methods are available for the direct quantification of histamine and its precursor and metabolites in arthropod brain. In this work, a method for the separation of histamine, its precursor histidine, and its metabolite N-methyl-histamine from brain extracts of a freshwater crustacean has been developed using capillary electrophoresis with laser-induced fluorescence detection. Molecules were tagged on their primary amine function with naphthalene-2,3-dicarboxaldehyde, but derivatized histamine and N-methyl-histamine exhibited poor stability in contrast to deriva…