Enhanced Capacity (enhanced + capacity)

Distribution by Scientific Domains


Selected Abstracts


The role of vegetation patterns in structuring runoff and sediment fluxes in drylands

EARTH SURFACE PROCESSES AND LANDFORMS, Issue 2 2005
Juan Puigdefábregas
Abstract The dynamics of vegetation-driven spatial heterogeneity (VDSH) and its function in structuring runoff and sediment fluxes have received increased attention from both geomorphological and ecological perspectives, particularly in arid regions with sparse vegetation cover. This paper reviews the recent findings in this area obtained from field evidence and numerical simulation experiments, and outlines their implications for soil erosion assessment. VDSH is often observed at two scales, individual plant clumps and stands of clumps. At the patch scale, the local outcomes of vegetated patches on soil erodibility and hydraulic soil properties are well established. They involve greater water storage capacity as well as increased organic carbon and nutrient inputs. These effects operate together with an enhanced capacity for the interception of water and windborne resources, and an increased biological activity that accelerates breakdown of plant litter and nutrient turnover rates. This suite of relationships, which often involve positive feedback mechanisms, creates vegetated patches that are increasingly different from nearby bare ground areas. By this way a mosaic builds up with bare ground and vegetated patches coupled together, respectively, as sources and sinks of water, sediments and nutrients. At the stand scale within-storm temporal variability of rainfall intensity controls reinfiltration of overland flow and its decay with slope length. At moderate rainfall intensity, this factor interacts with the spatial structure of VDSH and the mechanism of overland flow generation. Reinfiltration is greater in small-grained VDSH and topsoil saturation excess overland flow. Available information shows that VDSH structures of sources and sinks of water and sediments evolve dynamically with hillslope fluxes and tune their spatial configurations to them. Rainfall simulation experiments in large plots show that coarsening VDSH leads to significantly greater erosion rates even under heavy rainfall intensity because of the flow concentration and its velocity increase. Copyright © 2005 John Wiley & Sons, Ltd. [source]


Early cytoskeletal rearrangement during dendritic cell maturation enhances synapse formation and Ca2+ signaling in CD8+ T cells

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 10 2004
Marco Averbeck
Abstract The interplay between dendritic cells (DC) and T cells is a dynamic process critically depending on DC maturation. Ca2+ influx is one of the initial events occurring during DC/T cell contacts. To determine how DC maturation influences DC/T cell contacts, time-lapse video microscopy was established using TCR-transgenic CD8+ T cells from P14 mice. DC maturation shifted DC/T cell contacts from short-lived interactions with transient Ca2+ influx in T cells to long-lasting interactions and sustained Ca2+ influx of 30,min and more. Follow-up of DC/T cell interactions after 2,h using confocal microscopy revealed that long-lasting Ca2+ responses in T cells were preferentially associated with the formation of an immunological synapse involving CD54 and H2-Kb at the DC/T cell interface. Such synapse formation preceded MHC or B7 up-regulation, since DC developed into potent Ca2+ stimulators 7,h after initiation of maturation. Instead, the enhanced capacity of 7,h-matured DC to induce sustained Ca2+ responses in CD8+ T cells is critically dependent on the polarization and rearrangement of the cytoskeleton, as shown by Clostridium difficile toxin B inhibitor experiments. These data indicate that already very early after receiving a maturation stimulus, DC display enhanced cytoskeletal activity resulting in the rapid formation of immunological synapses and effective CD8+ T cell stimulation. [source]


Building drought management capacity in the Mekong River basin,

IRRIGATION AND DRAINAGE, Issue 3 2008
Wilfried Hundertmark
gestion de la sécheresse; développement des capacités; organisation de bassin; Mékong Abstract Over the past decades the Mekong River basin has experienced several droughts, the most recent of which occurred in the hydrological year 2004/2005. Impacts extended across agriculture, forestry, water resources, supply, industry, transport and the environment. In early 2006, the Mekong River Commission Secretariat initiated close consultations with the MRC member states Cambodia, Lao PDR, Thailand and Vietnam, aiming at the formulation of a common Drought Management Programme, which would enhance the existing drought management capacity and ensure effective support. This paper draws attention to the programme formulation process. It shows how national capacity needs were assessed and synthesized into a basin-wide capacity development programme. The paper concludes that in the context of international waters enhancing cooperation and capacity in drought management requires a strategic framework as an overall guideline for programme formulation and implementation. It defines a common terminology, mechanisms and linkages to integrated water resources management plans. The programme's long-term success depends on the ability to sustain the interest of the national partner institutions. Ultimately, enhanced capacity in drought management must demonstrate its impact on the level of vulnerability of the population living under drought-prone conditions. Copyright © 2008 John Wiley & Sons, Ltd. Au cours des dernières décennies, le bassin du Mékong a connu plusieurs sécheresses, la plus récente ayant eu lieu dans l'année hydrologique 2004/2005. L'impact a concerné l'agriculture, la forêt, les ressources en eau, la distribution, l'industrie, les transports et l'environnement. Au début de 2006, le Secrétariat de la Commission du Mékong a entamé des consultations étroites avec les états membres, le Cambodge, la RDP du Laos, la Thaïlande et le Vietnam, visant à l'élaboration d'un programme commun de gestion de la sécheresse, qui permettrait de renforcer les capacités existantes de gestion de la sécheresse et d'assurer un soutien efficace. Cet article attire l'attention sur le processus de formulation des programmes. Il montre comment les besoins nationaux de formation ont été évalués et synthétisés dans un programme de développement des capacités pour l'ensemble du bassin. L'article conclut que, dans le contexte des eaux internationales, le renforcement de la coopération et des capacités dans la gestion de la sécheresse a besoin d'un cadre stratégique d'ensemble et d'un guide global pour la formulation des programmes et leur mise en ,uvre. Il définit une terminologie commune, les mécanismes et les liens avec les plans de gestion intégrée des ressources en eau. Le succès à long terme du programme dépend de la capacité à maintenir l'intérêt des institutions nationales partenaires. En fin de compte, le renforcement des capacités dans la gestion de la sécheresse doit démontrer son impact sur le niveau de vulnérabilité de la population vivant dans les régions soumises à la sécheresse. Copyright © 2008 John Wiley & Sons, Ltd. [source]


Physicochemical parameters and magnetic speciation of Iron in Nakivubo Channel and Lake Victoria waters

LAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 2 2009
Naziriwo Betty Bbosa
Abstract Magnetic speciation technique was used for the determination of iron species in Nakivubo Channel and Lake Victoria waters. The method consisted of a column of supported Dowex 1-X18, 20,50 US mesh (Cl) surrounded by movable permanent magnets. Dowex was supported by a porous material to permit adequate passage of the eluent through the column. In the presence of an external magnetic field, enhanced capacity for adsorption of iron III was observed. The enhanced capacity is primarily due to the magnetic field produced and ion exchange sorption mechanism. The results show that, most of the Iron in Nakivubo Channel waters is in reduced ferrous form while, in the Lake Victoria waters, it exists in the oxidized ferric form. Physicochemical parameters for the field samples are discussed in this study. Turbidity levels in catchments with substantial vegetation were significantly lower than those without. pH values up to 13 was observed for some of the point source. The physicochemical parameters along Nakivubo Channel waters were relatively higher than the Lake Victoria waters indicating slow increasing pollution load along the Nakivubo Channel. [source]


Gene Expression Analysis in Cucumber Leaves Primed by Root Colonization with Pseudomonas chlororaphis O6 upon Challenge-Inoculation with Corynespora cassiicola

PLANT BIOLOGY, Issue 2 2004
M. S. Kim
Abstract: Root colonization by Pseudomonas chlororaphis O6, a non-pathogenic rhizobacterium, induced systemic resistance in cucumber against target leaf spot caused by Corynespora cassiicola. A cDNA library was constructed using mRNA extracted from cucumber leaves 12 h after inoculation with C. cassiicola, using plants colonized by O6. To identify genes involved in O6-mediated induced systemic resistance (ISR), we employed a subtractive hybridization method using mRNAs extracted from pathogen-challenged cucumber leaves of plants lacking colonization. Differential screening of the cDNA library led to the isolation of six distinct genes encoding a GTP binding protein, a 60S ribosomal protein, a hypersensitive-induced reaction protein, a ubiquitin extension protein, a pyridine nucleotide-disulfide oxidoreductase, and a signal recognition particle receptor. Expression of these genes was not induced by O6 colonization alone. Rather, transcript accumulation of these genes increased significantly faster and stronger in the O6 colonized than in non-colonized plants after challenge infection. Therefore, O6-mediated ISR may be associated with an enhanced capacity for the rapid and effective activation of cellular defence responses after challenge inoculation. [source]


The barley mutant emr2 shows enhanced resistance against several fungal leaf pathogens

PLANT BREEDING, Issue 2 2009
M. Jansen
Abstract Homozygous mlo -barley plants are resistant to barley powdery mildew but hypersusceptible to the rice blast fungus Magnaporthe oryzae. A mutational analysis was performed in the barley back-cross line BCIngrid mlo5 which led to the identification of two mutants with enhanced capacity to resist infections by M. oryzae, referred to as enhanced M. oryzae resistance mutants emr1 and emr2. Here, we report on the characterization of emr2 mutant plants which not only show an almost complete reduction in disease severity after inoculation with M. oryzae but are also resistant to the necrotrophic fungi Drechslera teres and Rhynchosporium secalis. Histological analysis revealed that resistance to M. oryzae was based mainly on the formation of papillae at sites of attempted penetration into epidermal cells. There was no progression of fungal growth into the mesophyll. Additionally, because of the presence of the mlo -allele, emr2 -plants retained resistance to powdery mildew. The emr2 -conditioned broad spectrum resistance was inherited as in a recessive manner. Monitoring of PR -gene expression and enzymatic activity of peroxidases revealed a constitutively activated defence in emr2. [source]


The effect of wealth and real income on wildlife consumption among native Amazonians in Bolivia: estimates of annual trends with longitudinal household data (2002,2006)

ANIMAL CONSERVATION, Issue 3 2010
R. Godoy
Abstract Over the last decades, native Amazonians have put increasing pressure on animal wildlife owing to growth in demand. Across societies, household monetary income and wealth shape food consumption; hence, so it is natural to ask what effect might these variables have on the demand for wildlife consumption among native Amazonians, particularly as they gain a stronger foothold in the market economy and increasing de jure stewardship over their territories. Prior estimates of the effects of household monetary income and household wealth on wildlife consumption among native Amazonians have relied on cross-sectional data and produced unclear results. The goal of this research was to improve the precision of previous estimates by drawing on a larger sample and on longitudinal data. The analysis draws on a dataset composed of five consecutive annual surveys (2002,2006, inclusive) from 324 households in a native Amazonian society of foragers and farmers in Bolivia (Tsimane'). Multiple regression analysis is used to estimate the association between wildlife consumption and monetary income and wealth. Wildlife consumption bore a positive association with the level of household wealth and no significant association with household monetary income. Among Tsimane', the main internal threat to wildlife conservation in the short run will likely arise from increases in wealth, probably from the enhanced capacity that selected physical assets (e.g. guns) have in the capture of animal wildlife. [source]


Expression of pheromone biosynthesis activating neuropeptide and its receptor (PBANR) mRNA in adult female Spodoptera exigua (Lepidoptera: Noctuidae)

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 1 2010
Yunxia Cheng
Abstract The full-length cDNA of pheromone biosynthesis activating neuropeptide receptor (PBANR) was cloned from the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae); it included an open reading frame of 1,053,bp encoding 350 amino acids. The PBANR of S. exigua (SePBANR) was structurally characteristic of G protein,coupled receptor and its amino acid sequence shared 98% identity with the PBANR of Spodoptera littoralis. Both pheromone biosynthesis activating neuropeptide (PBAN) and PBANR mRNA abundance were measured in the brain-subesophageal ganglion complex, pheromone gland, ventral nerve cord, and ovary of S. exigua female moths by real-time RT-PCR. The abundance of PBAN mRNA in brain-subesophageal ganglion complex and PBANR mRNA in pheromone gland was significantly greater compared to other tissues, suggesting that the ligand-receptor relationship of PBAN and PBANR exists quantitatively in S. exigua. Both PBAN and PBANR expression displayed a remarkable diurnal rhythm, for they were low and stable during the photophase (07:00,21:00) and increased markedly during the scotophase (with a maximum abundance at 23:30) in 3-day-old female moths. The abundance of PBAN and PBANR increased steadily from the 1st day to the 5th day of the adult female life. The pattern of both diurnal and daily expression of PBAN and PBANR mRNA were coincident with enhanced capacity of sex pheromone release and mating of S. exigua moths during the same period. We infer from these results that pheromone biosynthesis and release in S. exigua is regulated by PBAN via up-regulating synthesis. © 2010 Wiley Periodicals, Inc. [source]