Search results for "Environmental engineering"
showing 10 items of 2674 documents
Agroecology and Strategies for Climate Change
2012
; Sustainable agriculture is a rapidly growing field aiming at producing food and energy in a sustainable way for humans and their children. Sustainable agriculture is a discipline that addresses current issues such as climate change, increasing food and fuel prices, poor-nation starvation, rich-nation obesity, water pollution, soil erosion, fertility loss, pest control, and biodiversity depletion.Novel, environmentally-friendly solutions are proposed based on integrated knowledge from sciences as diverse as agronomy, soil science, molecular biology, chemistry, toxicology, ecology, economy, and social sciences. Indeed, sustainable agriculture decipher mechanisms of processes that occur fro…
Impact d'anciennes activités minières sur la zone critique : exemple des mines de plomb et d'argent de Peisey-Nancroix (19ème-20ème siècle)
2018
International audience; A better understanding of long-term trace metals dispersal and their bioavailability in the critical zone is required to anticipate future impacts of present-day mining activity. The Pb-Ag district of Peisey-Nancroix (northern French Alps) is an excellent target to study the long-term environmental impacts (> 150 years) of former mines and trace metal dispersal in the critical zone, considering that every steps of the mining cycle, from ore extraction to ore processing, were located on a few hectares site that has been unmodified since mine closure in 1866 (no reclamation). A cross-disciplinary study is conducted using several proxies (ore, waste dumps, soil, water, …
Prevalence of Mycobacterium bovis in agroecosystems : analysis of potential environmental reservoirs (soil, fresh water, soil fauna and aquatic fauna…
2016
Bovine tuberculosis is an infectious disease caused by Mycobacterium bovis. This disease affects cattle, and many species of domestic and wild mammals, and humans. The circulation of the bacteria in various multi-host systems promotes the maintenance of the disease and the contamination of cattle in the vicinity. Beside direct transmission of the bacteria through the respiratory route, indirect transmission, through inhalation or ingestion of environmental matrices contaminated by an infected animal excretory, is suspected in several countries. Environmental contamination with M. bovis appears to be a crucial factor in the persistence of the infection in multi-host systems. In Côte d'Or, a …
Variabilité intra-saisonnière et multi-décennale de la téléconnexion entre les pressions de surface (100°W–50°E ; 30°–70°N) et les ENSO/LNSO (1873–19…
2000
Abstract The relationships between an index of the NINO3.4 region and the wintertime sea level pressure (hereafter SLP) anomalies on the extratropical North Atlantic and the bordering areas (100°W–50°E; 30°–70°N) are studied for 1873–1996. This study emphasizes the need of a careful pooling of months and the multi-decadal variability of the ENSO/LNSO influence on the extratropical North Atlantic. We calculate the mean monthly climate anomalies for the 20 warmest and the 20 coldest NINO3.4 (170°–120°W; 5°N–5°S) years from October to March. The composite of SLP anomalies for the 20 warmest NINO3.4 years shows an anomalous trough centered near 30°W in November–December, and positive (respectiv…
Global equatorial variability of 850 and 200 hPa zonal winds from rawinsondes between 1963 and 1989
1995
The longitude-height-time variability of 3-month averaged zonal wind anomalies at 850 and 200 hPa over the equatorial area (5{degrees}N-5{degrees}S) is analyzed using a three-dimensional dataset constructed from rawinsonde data (1963-1989). The first mode, closely related to the Southern Oscillation Index, suggests a strong vertical coupling associated with a horizontal out-of-phase pattern between the central/western Pacific and the remainder of the equatorial belt. The vertical coupling appears to be phase-locked to the annual cycle with strongest intensities found over South America and near the maritime continent early in the calendar year and over the Pacific basin and Africa during th…
Sahel droughts and Enso dynamics
1996
Correlations between summer Sahel rainfall and Southern Oscillation Index has increased during the last thirty years. At high frequency time scale (periods lower than 8 years), an intertropical Atlantic zonal divergent circulation anomaly is forced by the difference of sea surface temperature (SST) anomalies between the eastern equatorial parts of Pacific and Atlantic. This zonal connection worked well during most of the E1 Nino/Southern Oscillation (ENSO) events occurring after 1970; positive/negative SST anomalies in the eastern Pacific/Atlantic led to rainfall deficits over the whole West Africa. At low frequency time scale (periods greater than 8 years), positive SST anomalies in the In…
Rainfall variability in subequatorial America and Africa and relationships with the main sea-surface temperature modes (1951–1990)
1995
The rainfall variability of subequatorial South America and Africa is poorly documented owing to the scarcity of data. We present a new land-only data set of monthly precipitation from 1951 to 1990, focusing on subequatorial South America and Africa, which improves the knowledge of rainfall variability and allows comparisons with GCM outputs. The results of multivariate analyses are compared with those performed on the best actual global rainfall data set developed by Mike Hulme. The main modes of bimonthly rainfall variability are not located in the major rain-forest basins of Za'ke and Amazonia, but rather on the tropical margins, such as Venezuela or Sudan, and near-coastal equatorial ar…
Guinean and sahelian rainfall anomaly indices at annual and monthly scales (1933-1990)
1994
The annual and monthly rainfall variability in north tropical Africa are analysed by principal component analysis in order to detect the main coherent modes. The Sahel constitutes the first mode, although it is divided close to 1O"W into an Atlantic section and a Continental section. The Guinean zone is less coherent, and is divided into distinct modes. The subequatorial area never formed a distinct mode. Rainfall variability for the coherent areas is constructed from rainfall anomaly indices (RAI), based on the coherent areas, and a rainfall typology taking into account the spatial pattern of the rainfall anomaly fields and the intensity of the anomaly. Their evolution (mainly since 1950) …
The relationship between copper accumulated in vineyard calcareous soils and soil organic matter and iron
2002
International audience; The intensive use for over 100 yr of copper sulfate (Bordeaux mixt.) to fight mildew in vineyards has led to a substantial accumulation of copper (Cu) in surface soils. To assess the effects of such large concns., the surface soils of 10 Burgundy vineyards were sampled and analyzed for total org. matter (carbon and nitrogen) and metal (copper and iron) contents. Phys. (i.e. size fractionation) and chem. (sequential extn.) methods were used to det. the distribution of these elements. The most Cu-contaminated plots showed the largest accumulation of org. carbon and Cu in the coarse sand and fine sand fractions. Copper was strongly correlated with org. carbon and org. …
Extraction of essential oil from Aloysia citriodora Palau leaves using continuous and pulsed ultrasound: Kinetics, antioxidant activity and antimicro…
2018
International audience; The impact of continuous and pulsed ultrasound pre-treatments (15, 30 and 45 min) followed by conventional hydrodistillation on the characteristics of extracted essential oils (EOs) from dried leaves of Aloysia citriodora Palau was evaluated for the first time. Chemical composition of EOs, antibacterial and antioxidant activities, as well as the contents in heavy metals (iron, copper, lead, arsenic, and cadmium) were determined. Pretreating the leaves with ultrasound (continuous and pulsed), before hydrodistillation, resulted in shorter extraction time (93.81–121.16 min) and higher extraction yields (2.8 (v/w) %) (p < 0.05), compared to the non-sonicated leaves (extr…