Temporal variations of rhizosphere and bulk soil chemistry in a Douglas fir stand

Rhizosphere soil can play a central role in the maintenance of the soil–plant system and influencing the biogeochemistry of forest ecosystems. However, rhizospheric studies in situ to understand the ecosystem functions are still lacking. Therefore, the objectives of the present study were to examine the differences in the chemical properties such as the pH, organic C, exchangeable base cations (EBC=Mg2++Ca2++K+), exchangeable acidity and cation exchange capacity (CEC) of three soil fractions (Bulk, B; Rhizosphere, R and Rhizosphere Interface, RI) and the evolution of chemical properties of soil samples collected in March and June from a Douglas fir ecosystem located in the Beaujolais Mounts in France. Most of the variables measured (organic matter, CEC and EBC) increased significantly in the same order (BbRbRI), indicating that the rhizosphere was a favorable interface for tree nutrition. These processes were more pronounced in June than in March, as the temperature and biological activities are normally higher in June than in March. The temporal variations of Al charge in R and B seem to depend on OH−, organic complexation and H+ production by roots and/or the organic matter degradation in the bulk soil. In the rhizosphere, the H+ or OH− production depends on the N cycle. The results of this study and the support of independent mineralogical study using the same soil fractions, and of other field studies on the same site have all pointed at the importance of rhizosphere as an excellent indicator for the understanding of the ecosystem dynamics in both short- and long-term

Seasonal variations in the chemistry of acid rhizospheric and bulk soil under Douglas fir

International audienc

Venous thromboembolism risk and prophylaxis in hospitalised medically ill patients The ENDORSE Global Survey

Limited data are available regarding the risk for venous thromboembolism (VIE) and VIE prophylaxis use in hospitalised medically ill patients. We analysed data from the global ENDORSE survey to evaluate VTE risk and prophylaxis use in this population according to diagnosis, baseline characteristics, and country. Data on patient characteristics, VIE risk, and prophylaxis use were abstracted from hospital charts. VTE risk and prophylaxis use were evaluated according to the 2004 American College of Chest Physicians (ACCP) guidelines. Multivariable analysis was performed to identify factors associated with use of ACCP-recommended prophylaxis. Data were evaluated for 37,356 hospitalised medical patients across 32 countries. VIE risk varied according to medical diagnosis, from 31.2% of patients with gastrointestinal/hepatobiliary diseases to 100% of patients with acute heart failure, active noninfectious respiratory disease, or pulmonary infection (global rate, 41.5%). Among those at risk for VTE, ACCP-recommended prophylaxis was used in 24.4% haemorrhagic stroke patients and 40-45% of cardiopulmonary disease patients (global rate, 39.5%). Large differences in prophylaxis use were observed among countries. Markers of disease severity, including central venous catheters, mechanical ventilation, and admission to intensive care units, were strongly associated with use of ACCP-recommended prophylaxis. In conclusion, VIE risk varies according to medical diagnosis. Less than 40% of at-risk hospitalised medical patients receive ACCP-recommended prophylaxis. Prophylaxis use appears to be associated with disease severity rather than medical diagnosis. These data support the necessity to improve implementation of available guidelines for evaluating VIE risk and providing prophylaxis to hospitalised medical patients

Venous Thromboembolism Risk and Prophylaxis in the Acute Care Hospital Setting (ENDORSE Survey) Findings in Surgical Patients

Objective: To evaluate venous thromboembolism (VTE) risk in patients who underwent a major operation, including the use of, and factors influencing, American College of Chest Physicians-recommended types of VTE prophylaxis