4,699 research outputs found
A MODIS based tool to assess inundation patterns: an example for the Paraná Delta River
Wetlands are one of the most productive yet altered ecosystems due to human activities across the world. They rely largely on their water flow to provide several ecosystem functions. Then, to develop a land use plan that allows a productive use maintaining the ecological integrity it is critical to understand the flooding patterns. In that sense, the capability of remote sensors to estimate water cover for large areas at detailed spatial and temporal scales can help to develop managerial decision tools. However, the temporal and spatial variation of water components may alter it spectral properties. We studied the capability of different MODIS derived spectral indices to estimate water cover or water presence-absence. The study region was the Paraná Delta River, which is a 2 Mha wetland area. Between all the models evaluated, one based on the spectral index NDWI1 ((Red – SWIR) / (Red + SWIR)) was the most accurate. A NDWI1 = -0.2 threshold allowed to separate those pixels with less than those with more than 60% of water cover with an accuracy of 91%. By this model, we described the flooding patterns of different landscape units of the region during the last 12 years and classified the region according to the impact of ordinary and extraordinary flooding events. We consider this information can help to improve the knowledge about the hydrodynamics, monitor the impact of some activities and develop a more sustainable regional planning.Los humedales están entre los ecosistemas más productivos y, a su vez, están fuertemente alterados por el
ser humano. Los múltiples servicios que proveen dependen en gran medida del flujo de agua. Por ello, para
desarrollar un plan de uso de la tierra que permita un uso productivo manteniendo la integridad ecológica es
fundamental comprender los patrones de inundación. En ese sentido, la capacidad de los sensores remotos
de estimar la cobertura de agua en áreas grandes a escalas espaciales y temporales detalladas contribuirían
a desarrollar herramientas que favorezcan la toma de decisiones. Sin embargo, la variación temporal y espacial de los componentes del agua puede alterar sus propiedades espectrales. Se estudió la capacidad de
diferentes índices espectrales derivados del sensor MODIS para estimar la cobertura de agua o la presencia/
ausencia de agua. La región de estudio fue el Delta del Río Paraná, un humedal de 2 millones de hectáreas. Entre todos los modelos evaluados, uno basado en el índice espectral NDWI1 ((Rojo - SWIR) / (Rojo + SWIR))
fue el más preciso. Un valor umbral de NDWI1 = -0,2 permitió separar píxeles con menos de 60% de cobertura
de agua de aquellos con más del 60% con una precisión del 91%. Mediante este modelo se describieron los
patrones de inundación de diferentes unidades de paisaje de la región durante los últimos 12 años y se clasificó la región de acuerdo al impacto de los eventos de inundación ordinarios y extraordinarios. Consideramos
que esta información puede ayudar a mejorar el conocimiento sobre la hidrodinámica, monitorear el impacto
de algunas actividades y desarrollar una planificación regional más sostenible.EEA Concepción del UruguayFil: Durante, Martin. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Di Bella, Carlos Marcelo. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Clima y Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información; Argentin
BMP2 and TGF-β Cooperate Differently during Synovial-Derived Stem-Cell Chondrogenesis in a Dexamethasone-Dependent Manner
Recent studies highlighting mesenchymal stem cell (MSC) epigenetic memory suggest that a different differentiation medium may be required depending on the tissue of origin. As synovial-derived stem cells (SDSCs) attract interest we aimed to investigate the influence of TGF-β1, BMP-2 and dexamethasone on SDSC chondrogenesis in vitro. We demonstrate that dexamethasone-free medium led to enhanced chondrogenic differentiation at both the mRNA and matrix level. The greatest COL2A1/COL10A1 ratio was detected in cells exposed to a combination medium containing 10 ng/mL BMP-2 and 1 ng/mL TGF-β1 in the absence of dexamethasone, and this was reflected in the total amount of glycosaminoglycans produced. In summary, dexamethasone-free medium containing BMP-2 and TGF-β1 may be the most suitable when using SDSCs for cartilage tissue regeneration
Orally Co-Infected Aedes albopictus from La Reunion Island, Indian Ocean, Can Deliver Both Dengue and Chikungunya Infectious Viral Particles in Their Saliva
Dengue (DEN) and chikungunya (CHIK) are two mosquito borne infections transmitted by Aedes mosquitoes in the tropical world. Ae. albopictus has been shown to efficiently transmit the new variant of CHIK virus (CHIKV) that emerged in the Indian Ocean region in 2005. At the same time, this vector is able to sustain outbreaks due to DEN virus (DENV). Since this CHIK emergence, co-infections DENV-CHIKV in humans have been regularly reported. This phenomenon, known for a long time, may be due to two consecutive bites from two mosquitoes infected by one virus or by the bite of a mosquito infected by both viruses. We used two viral strains isolated in La Reunion Island, DENV-1 in 2004 and CHIKV in 2005, and co-infected an autochthonous strain of Ae. albopictus, testing experimentally one of the possible ways to get co-infections in humans. We were able to show the ability of Ae. albopictus to replicate simultaneously both arboviruses and, furthermore, to deliver both infectious viral particles concomitantly in their saliva. This finding is of particular interest since Ae. albopictus is now widely distributed all around the world and still expanding its geographical range
Differential responses of the mosquito Aedes albopictus from the Indian Ocean region to two chikungunya isolates
International audienceBACKGROUND: Aedes aegypti and Aedes albopictus are both vectors of chikungunya virus (CHIKV). The two Aedes species co-exist in the Indian Ocean region and were involved in the 2005-2006 CHIKV outbreaks. In the Reunion Island, a single mutation in the viral envelope has been selected that leads to high levels of replication in Ae. albopictus, and a short extrinsic incubation period as the virus could be found in saliva as early as two days after infection. An important question is whether this variant is associated with adverse effects impacting some mosquito life-history traits such as survival and reproduction. RESULTS: We performed experimental infections using three mosquito strains of Ae. aegypti Mayotte and Ae. albopictus (Mayotte and Reunion), and two CHIKV strains (E1-226A and E1-226V). Ae. aegypti Mayotte were similarly susceptible to both viral strains, whereas Ae. albopictus Mayotte and Ae. albopictus Reunion were more susceptible to CHIKV E1-226V than to E1-226A. In terms of life-history traits measured by examining mosquito survival and reproduction, we found that: (1) differences were observed between responses of mosquito species to the two viruses, (2) CHIKV infection only affected significantly some life-history traits of Ae. albopictus Reunion and not of the other two mosquito strains, and (3) CHIKV reduced the lifespan of Ae. albopictus Reunion and shortened the time before egg laying. CONCLUSION: We demonstrated that CHIKV only reduces the survival of Ae. albopictus from the Reunion Island. By laying eggs just before death, reproduction of Ae. albopictus from the Reunion Island is not reduced since other parameters characterizing oviposition and hatching were not affected
Heavy minerals in sediments from the Mošnica Cave: Implications for the pre-Quaternary evolution of the middle-mountain allogenic karst in the Nízke Tatry Mts., Slovakia
The cave deposits from the Mošnica Cave located on the northern slope of the Nízke Tatry Mts. were analysed by sedimentological, petrographical and mineralogical methods. Based on mineralogical study the cave sediments are composed of dolomite, quartz, muscovite, amphibole, chlorite, calcite, Kfeldspar and plagioclase. Heavy mineral assemblage is formed by garnet, zircon, apatite, monazite, tourmaline, staurolite, rutile, titanite, epidote, sillimanite, allanite, andalusite and barite. Opaque minerals are represented by ilmenite, pyrite, magnetite, Cr-spinel, Fe-oxyhydroxides and chalcopyrite. Detailed research of chemical composition of the heavy minerals points to their source rocks formed by granitoids, amphibolites and amphibolite gneisses representing the crystalline basement and probably by Triassic cover sediments of the Lúžna Formation. Presence of the allochthonous minerals in the cave from metamorphic complex recently occurred on the opposite southern slope of the Nízke Tatry Mts. indicates a past larger catchment area of the allogenic karst of Mošnica Valley on the pre-Quaternary less dissected terrain. A change of watershed boundary leading through the central range of the Nízke Tatry Mts. was probably connected with the tilting of this mountain range towards the north, in the compression regime during the Late Tertiary
Socioeconomics of the Production and Marketing of Haricot Beans (Phaseolus vulgaris L.) in the Western Highlands of Cameroon
There has been an increase in the demand for Haricot beans (Phaseolus vulgaris L.) in Cameroon, most especially from buyers of neighbouring countries and institutions that feed their members. This indicates the existence of opportunities for farmers to exploit the market system and effectively participate in the supply chain within and across national borders. However, farmers don’t make use of this opportunity resulting from multiple constraints ranging from low production levels, low income and inconsistency in market participation to high transaction cost. It is thus relevant to identify and address the constraints facing these farmers in a bid to improve production and market participation. This analyzes the factors influencing farmer’s participation in the production and marketing of haricot beans in the Western Highlands of Cameroon. Data was collected from 200 farmers in 24 villages in the Western Highlands of Cameroon and analyzed using descriptive and inferential statistical techniques. Findings indicate that the production and marketing of beans was dominated by older and married farmers with low educational background who depend on these for their livelihood. In addition, the farming system practiced, production season, seed type planted and access to production resources significantly influence the quantities produced and marketed. To enhance haricot beans production and marketing, the study opines that development interventions lay emphasis on infrastructural and technology improvement especially with regards to the provision and use of improved farm inputs. Keywords: Haricot beans, production, marketing, Western Highlands, Cameroo
La cubierta como centralidad de proyecto
En el presente trabajo reflexionamos sobre un proyecto de renovación e inclusión social y laboral para un barrio carenciado de recursos tanto en infraestructura como en la situación particular de cada familia. Creemos que es la creación de OPORTUNIDADES para crecer, es darle la herramienta necesaria para satisfacer las necesidades que creemos oportunas en base al análisis que hicimos.
El mercado del rio, como así lo llamamos, expresa a través de su escala y su forma un gran impacto visual. Alternando entre escalas humanas y edilicias de gran porte, estructuras en hormigón visto y la cubierta como una parte esencial del proyecto,
generamos un nuevo núcleo de encuentro social y productivo de valor barrial y patrimonial para la ciudad de Pueblo Esther.
Cabe destacar entonces su cubierta, sus texturas, sus transparencias, y sus espacios generados como potenciadores de un pequeño barrio productivo hacia una nueva centralidad de la zona.Universidad Nacional de Rosario. Facultad de Arquitectura, Planeamiento y Diseño. Rosario, Argentina
Characterization of <i>Aedes aegypti</i> innate-immune pathways that limit Chikungunya virus replication
Replication of arboviruses in their arthropod vectors is controlled by innate immune responses. The RNA sequence-specific break down mechanism, RNA interference (RNAi), has been shown to be an important innate antiviral response in mosquitoes. In addition, immune signaling pathways have been reported to mediate arbovirus infections in mosquitoes; namely the JAK/STAT, immune deficiency (IMD) and Toll pathways. Very little is known about these pathways in response to chikungunya virus (CHIKV) infection, a mosquito-borne alphavirus (Togaviridae) transmitted by aedine species to humans resulting in a febrile and arthralgic disease. In this study, the contribution of several innate immune responses to control CHIKV replication was investigated. In vitro experiments identified the RNAi pathway as a key antiviral pathway. CHIKV was shown to repress the activity of the Toll signaling pathway in vitro but neither JAK/STAT, IMD nor Toll pathways were found to mediate antiviral activities. In vivo data further confirmed our in vitro identification of the vital role of RNAi in antiviral defence. Taken together these results indicate a complex interaction between CHIKV replication and mosquito innate immune responses and demonstrate similarities as well as differences in the control of alphaviruses and other arboviruses by mosquito immune pathways
Topically applied Tetrapleura tetraptera stem bark extract promotes healing of excision and incision wounds in rats
Objective. The objective of the present study was to evaluate the in vivo wound healing effect of water extract of Tetrapleura tetraptera in stem-bark. Method: The healing activity was studied in 40 male rats using excision and incision wounds on normal and dexamethasone-suppressed wound healing. For each model, rats were divided in 4 groups as follows: control, dexamethasone, T. tetraptera and dexamethasone combined with T. tetraptera. Results: Data recorded exhibited a significant effect by the extract in the epithelialization time within 14 and 18 days of the normal and dexamethasone-induced healing delay rats respectively (p<0.05). The extract also significantly increased the wound tensile strength in dexamethasone treated rats. Histological examination of incision wounds of extract-treated group showed many fibroblasts and the same rats presented significant cutaneous tensile strength, suggesting important collagen crosslinkage. Conclusion: This study illustrated an excellent potential of the bark of T. tetraptera therapy on dermal wound healing with a possible mechanism of action related to epithelialization, contraction and tensile strength improvement
Adaptation of the AAPOR Final Disposition Codes for the German Survey Context (Version 1.0)
Detailed and precise documentation is the key to scientific research and of particular importance for high-quality data collection. An important parameter for each survey is the response rate. It reflects how many persons initially invited to participate finally took part in a survey interview. In any case, every survey based on a probability sample should report its response rate, since it provides first and easily assessable information about the data collection process. The American Association for Public Opinion Research (AAPOR) has proposed Standard Definitions that include final disposition codes as guidelines for reporting of response rates. These definitions take various modes of data collection into account. However, the final disposition codes proposed by AAPOR are based on sampling and data collection practices in the context of the United States. To date, there is no clear guidance on how to adapt these definitions in a comparable manner for the German context. This survey guideline aims to close this information gap and offers operational definitions for the AAPOR final disposition codes that are applicable in the German context
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