Search results for "PRECIPITATION"
showing 10 items of 826 documents
Cropping system dynamics, climate variability, and seed losses among East African smallholder farmers: a retrospective survey.
2014
Abstract Climate variability directly affects traditional low input and rain-fed farming systems, but few studies have paid attention retrospectively to the cropping system’s ability to mitigate climate risk. This study analyzes the impacts of rainfall variability on farmers’ seed variety losses over time, considering changes in smallholder farming systems. The cropping system dynamics, in favoring maize at the expense of sorghum and pearl millet, have induced an increasing risk of seed loss during drought. Combining ecological anthropology and climatology, a retrospective survey asking farmers about the period 1961–2006 was carried out at three altitudinal levels (750, 950, and 1100 m) on …
Réponse des interactions plante-sol aux régimes de précipitations
2018
Water availability governs terrestrial nutrient cycles by impacting the functioning of both plants and of soil microorganisms. The predicted changes in precipitation patterns (i.e. the magnitude and frequency of precipitation events) associated with climate change, will thus likely have important consequences on ecosystem functioning. Dry and seasonally dry ecosystems are particularly vulnerable to changes in precipitation patterns, as they are already constrained to a large extent by water availability. However, more mesic systems may also experience dry periods that may impact plant-soil functions. In this thesis, experiments in soil-only systems and plant-soil systems were used to gain i…
Effects of precipitation regime on soil bacterial and fungal activity upon rewetting of a plant-soil system using 18O-SIP: depth matters
2017
EASPEBIOmEDOCT INRA; Climate change is predicted to affect not only the amount but also the temporal distribution of rain. Changes in frequency and amplitude of rain events, likely shape the activity of plants and soil microbes. Fluctuating water conditions will differ with soil depth between precipitation patterns, affecting plant growth and may result in differential microbial response upon rewetting. Our objective was to investigate, in plant-soil systems, the response of the metabolically active microbial communities to a rewetting event and to which extent this was modulated by 1) soil depth and 2) precipitation legacy. Wheat planted in soil mesocosms were subjected to frequent or infr…
Legacy effects of contrasting water and N-availability patterns on plantmicrobial response to rewetting
2019
National audience; Introduction. Shifts in the frequency and magnitude of rain events (precipitation regime) associated with climate change may affect plant morphological and physiological strategies as well as soil microbial activity.Objectives. The objective of this study was to determine i) how precipitation history shapes the response dynamics of soil bacterial and fungal communities to rewetting, as well as plant-microbial competition for N, and ii) how the N status of the system may modulate the effect of precipitation regime.Materials & methods. The legacy effects of 12 weeks of contrasting precipitation (frequent or infrequent watering, equal total water input) and N inputs was asse…
Elaboration de céramiques transparentes Er YAG : synthèse de poudre par co-précipitation et frittage SPS
2013
Yttrium aluminium garnet (YAG, Y3Al5O12) transparent ceramics have attracted much attention since it can replace single crystals as host materials in solid state heat capacity lasers. These polycrystalline ceramics present improved mechanical and spectroscopic properties, as well as a better heat conductivity, lower fabrication costs for larger size materials. Furthermore, it is possible to reach higher doping concentrations as well a uniform distribution. Doping YAG with Erbium (Er:YAG) allows eye-safe emission at 1645nm. Moreover, a low doping rate (0.5%at.) enables upconversion process during laser operation. Conditions for transparency are amongst others, the absence of defects, a high …
α-Aminophosphonates, Phosphinates, and Phosphine Oxides as Extraction and Precipitation Agents for Rare Earth Metals, Thorium, and Uranium : A Review
2022
α-Aminophosphonates, -phosphinates, and -phosphine oxides are a group of organophosphorus compounds that were investigated as extraction agents for rare earth (RE) metals and actinoids for the first time in the 1960s. However, more systematic investigations of their extraction properties towards REs and actinoids were not started until the 2010s. Indeed, recent studies have shown that these α-amino-functionalized compounds can outperform the commercial organophosphorus extraction agents in RE separations. They have also proven to be very efficient extraction and precipitation agents for recovering Th and U from RE concentrates. These actinoids coexist with REs in some of the commercially im…
Effect of the Cement and Limestone Industry on the Chemical Properties of Water Beneath Tree Canopies
2018
This study is a continuation of earlier research aimed at determining the changes in the quality of precipitation beneath the canopy in pine stands affected by the emission of alkaline pollutants. This study was conducted in the Gorazdze Forest District, in a forest complex in south-western Poland affected by the cement and limestone industry. The rainwater measurements under the canopy of Scots pine were made according to the methodology of the environmental monitoring. Wet and dry deposits, thus the total pollution load brought into the forest ecosystem, were analysed. The pH and electrical conductivity was measured in collected water samples. The results showed differences between precip…
The influence of yeast glycosylated proteins on tannins aggregation in model solution
2004
<p style="text-align: justify;">The incidence of glycosylated yeast proteins on tannins aggregation in model solution was investigated using the spectrophotometric method (absorbance 700 nm). Glycosylated proteins released by two commercial <em>Saccharomyces cerevisiae</em> strains (RC212 and BM 45) during alcoholic fermentation in synthetic media, glycosylated proteins extracted by Peat’s method and industrial glycosylated proteins purified and separated by chromatography on Sepharose Concanavalin A were used to visualize effects on tannins aggregation. Results showed that tannins aggregation was limited by the glycosylated proteins according to their origin and their mod…
The deubiquitinase USP11 is a versatile and conserved regulator of autophagy
2021
Autophagy is a major cellular quality control system responsible for the degradation of proteins and organelles in response to stress and damage to maintain homeostasis. Ubiquitination of autophagy-related proteins or regulatory components is important for the precise control of autophagy pathways. Here, we show that the deubiquitinase ubiquitin-specific protease 11 (USP11) restricts autophagy and that KO of USP11 in mammalian cells results in elevated autophagic flux. We also demonstrate that depletion of the USP11 homolog H34C03.2 in Caenorhabditis elegans triggers hyperactivation of autophagy and protects the animals against human amyloid-β peptide 42 aggregation-induced paralysis. USP11…
Analysis of particles size distributions in Mg(OH)2 precipitation from highly concentrated MgCl2 solutions
2022
Magnesium is a raw material of great importance, which attracted increasing interest in the last years. A promising route is to recover magnesium in the form of Magnesium Hydroxide via precipitation from highly concentrated Mg2+ resources, e.g. industrial or natural brines and bitterns. Several production methods and characterization procedures have been presented in the literature reporting a broad variety of Mg(OH)2 particle sizes. In the present work, a detailed experimental investigation is aiming to shed light on the characteristics of produced Mg(OH)2 particles and their dependence upon the reacting conditions. To this purpose, two T-shaped mixers were employed to tune and control the…