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Valley Region (valley + region)
Selected AbstractsFactors influencing the occurrence of entomopathogenic nematodes in the Central Rift Valley Region of KenyaAFRICAN JOURNAL OF ECOLOGY, Issue 2008S. W. Mwaniki Abstract A survey for entomopathogenic nematodes in the central Rift valley region of Kenya was conducted at altitudes between 1800 and 3000 m above sea level and from croplands and noncropland habitats. The sampling depth was 0,30 cm. GPS (global positioning system) was used to measure site positions. One hundred and twelve soil samples were collected and entomopathogenic nematodes trapped through Galleria mellonella. Entomopathogenic nematode presence was demonstrated by G. mellonella mortality and viable ones bulked through the same host. Nematode recoveries from two consecutive extractions were 30% per extraction and 52% for cumulative extractions. Recoveries from agro ecological zones ranged between 18% and 71%. Recovery frequency was higher from disturbed cropland habitats than the stable noncrop habitats. Steinernema species were more frequent than Heterorhabditis (9 : 1). Nematode occurrence clustered at 2,3% carbon and pH 5.3,6.3 with no specific pattern demonstrated from soil types. Nematode species of the two genera from high altitudes lost their culturing ability within 1 month of isolation. There was a tendency for recovering both nematode genera at the shores of water bodies. This is the first report of Steinernema yirgalemense and S. weiseri in Kenya and of S. karii in the central Rift valley region. The Heterorhabditis species has not been confirmed yet. This has widened the genetic base of entomopathogenic nematodes from Kenya. The entomopathogenic nematodes are available for developement as biological control agents of athropod pests. [source] Modelling natural conditions and impacts of consumptive water use and sedimentation of Lake Abaya and Lake Chamo, EthiopiaLAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 2 2006Seleshi Bekele Awulachew Abstract There is few available information regarding the water resource systems of Abaya Lake and Chamo Lake, which are found in the Southern Rift Valley Region of Ethiopia. This paper describes modelling of the water balance components of these lakes, as well as the impacts of water uses, and sediment transport and deposition in the lakes. The various parameters and data needed for the water balance model are derived on the basis of various surveys, analysis of data and modelling efforts. The watershed characteristics are derived using geographical information system, whereas the morphometry of the lakes is investigated by undertaking bathymetry surveys. The hydrometeorological components of this lake system also were investigated through the development of relevant database and information systems, by identifying regional relationships, and by a rainfall-run-off model. These information systems have subsequently been integrated to model the water balance of the two lakes, and simulating the in-lake water levels. Several scenarios reflecting the natural conditions, water consumptive development possibilities, and sedimentation impacts have been investigated in this study. Based on the model simulation results, and on the computation of the life expectancies of the two lakes, it was found that sediment inflow and deposition significantly threaten their existence. [source] Aerosol Direct Radiative Impact Experiment (ADRIEX) overviewTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue S1 2007E. J. Highwood Abstract The Aerosol Direct Radiative Experiment (ADRIEX) took place over the Adriatic and Black Seas during August and September 2004 with the aim of characterizing anthropogenic aerosol in these regions in terms of its physical and optical properties and establishing its impact on radiative balance. Eight successful flights of the UK BAE-146 Facility for Atmospheric Airborne Measurements were completed together with surface-based lidar and AERONET measurements, in conjunction with satellite overpasses. This paper outlines the motivation for the campaign, the methodology and instruments used, describes the synoptic situation and provides an overview of the key results. ADRIEX successfully measured a range of aerosol conditions across the northern Adriatic, Po Valley and Black Sea. Generally two layers of aerosol were found in the vertical: in the flights over the Black Sea and the Po Valley these showed differences in chemical and microphysical properties, whilst over the Adriatic the layers were often more similar. Nitrate aerosol was found to be important in the Po Valley region. The use of new instruments to measure the aerosol chemistry and mixing state and to use this information in determining optical properties is demonstrated. These results are described in much more detail in the subsequent papers of this special issue. Copyright © 2007 Royal Meteorological Society [source] Diversity of Cicadellidae in agricultural production areas in the Ovens Valley, north-east Victoria, AustraliaAUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 3 2010Piotr Tr, bicki Abstract There is a paucity of data on the distribution of Cicadellidae (leafhoppers) in Australia. This study quantifies the relative abundance, seasonal activity and diversity of leafhoppers in the Ovens Valley region of north-east Victoria, Australia. Species diversity and abundance was assessed at four field sites in and around the field borders of commercially grown tobacco crops using three sampling techniques (pan trap, sticky trap and sweep net). Over 51 000 leafhopper samples were collected, with 57 species from 11 subfamilies and 19 tribes identified. Greater numbers and diversity of leafhoppers were collected in yellow pan traps. The predominant leafhopper collected was Orosius orientalis (Matsumura). Twenty-three leafhopper species were recorded for the first time in Victoria and eight economically important pest species were recorded. Seasonal activity of selected leafhopper species, covering two sampling seasons, is presented. [source] Near-diploid and near-triploid human sporadic colorectal adenocarcinomas differ for KRAS2 and TP53 mutational statusGENES, CHROMOSOMES AND CANCER, Issue 2 2003Walter Giaretti Mutations of the KRAS2 protoncogene and inactivation of the TP53 oncosuppressor gene have been suggested to contribute to chromosomal instability (CIN) and aneuploidy in colorectal cancer (CRC). Previous work has also shown that the degree of DNA ploidy [DNA index (DI)], as obtained by flow cytometry in CRC, is non-randomly distributed and, in particular, that DI near-diploid and near-triploid values are well separated by a low-probability valley region. At present, it is not known whether a relationship exists between DI and the mutational status of KRAS2 and TP53. Multiple samples obtained from 35 human sporadic CRCs have been used to provide nuclei suspensions for flow cytometric analysis and sorting of specific DI subpopulations. Sorted nuclei were then used to analyze the high-microsatellite-instability (MSI-H) phenotype and the mutation spectrum of the KRAS2 and TP53 genes. A single MSI-H case was detected. There were 6 DNA diploid (DI = 1) and 29 aneuploid (DI , 1) CRCs, with the DI aneuploid cases non-randomly subdivided in 9 near-diploid (DI , 1 and DI , 1.4), 8 near-triploid (1.4 < DI < 1.6), and 12 high-aneuploid (DI , 1.6) cases. Proximal CRCs were more often DNA diploid and near-diploid than distal ones, and Dukes' C cases were more commonly high-aneuploid than Dukes' B. Moreover, the incidence of mutations of the KRAS2 and TP53 genes was lowest among the DNA near-triploid subpopulations and highest among the near-diploid ones. We suggest that DNA near-diploid and near-triploid subpopulations in human sporadic CRC reflect different genetic mechanisms of CIN and have a potentially different clinical behavior. © 2003 Wiley-Liss, Inc. [source] Factors influencing the occurrence of entomopathogenic nematodes in the Central Rift Valley Region of KenyaAFRICAN JOURNAL OF ECOLOGY, Issue 2008S. W. Mwaniki Abstract A survey for entomopathogenic nematodes in the central Rift valley region of Kenya was conducted at altitudes between 1800 and 3000 m above sea level and from croplands and noncropland habitats. The sampling depth was 0,30 cm. GPS (global positioning system) was used to measure site positions. One hundred and twelve soil samples were collected and entomopathogenic nematodes trapped through Galleria mellonella. Entomopathogenic nematode presence was demonstrated by G. mellonella mortality and viable ones bulked through the same host. Nematode recoveries from two consecutive extractions were 30% per extraction and 52% for cumulative extractions. Recoveries from agro ecological zones ranged between 18% and 71%. Recovery frequency was higher from disturbed cropland habitats than the stable noncrop habitats. Steinernema species were more frequent than Heterorhabditis (9 : 1). Nematode occurrence clustered at 2,3% carbon and pH 5.3,6.3 with no specific pattern demonstrated from soil types. Nematode species of the two genera from high altitudes lost their culturing ability within 1 month of isolation. There was a tendency for recovering both nematode genera at the shores of water bodies. This is the first report of Steinernema yirgalemense and S. weiseri in Kenya and of S. karii in the central Rift valley region. The Heterorhabditis species has not been confirmed yet. This has widened the genetic base of entomopathogenic nematodes from Kenya. The entomopathogenic nematodes are available for developement as biological control agents of athropod pests. [source] Gender and Migration in the Central Valleys of OaxacaINTERNATIONAL MIGRATION, Issue 1 2008Jeffrey H. Cohen In this paper, we examine the gendered nature of international and internal migration that originates in the central valleys of Oaxaca, Mexico. Our goals are to define migration patterns and outcomes for Oaxacan women from the central valleys region and note the differences that mark migrant men and women. We use ethnographic data from anthropological research in 12 of Oaxaca's central valley communities to argue that local concepts of what defines correct behaviour (for both men and women) are critical to the outcomes and the differences that exist in the practices of migrant men and women. Dans cette étude, nous examinons le caractère sexospécifique de la migration interne et internationale prenant sa source dans les vallées centrales d'Oaxaca au Mexique. Nous nous efforçons de définir les schémas migratoires et ce qui en résulte pour les femmes originaires de la région des vallées centrales d'Oaxaca, en notant les différences entre les migrants hommes et femmes. A cet effet, nous utilisons des données ethnographiques recueillies dans le cadre de recherches anthropologiques menées dans douze communautés des vallées centrales d'Oaxaca, et en tirons la conclusion que les concepts locaux de comportement correct (à la fois pour les hommes et pour les femmes) revêtent une importance fondamentale dans l'appréciation des différences existant entre les pratiques des migrants et des migrantes. En este articulo, se examinan las cuestiones de genero en la migración internacional e interna que se originan en los valles centrales de Oaxaca, México. Ello con el objeto de definir los patrones migratorios y los resultados de los mismos para las mujeres de Oaxaca provenientes de los valles centrales y observar las diferencias existentes entre las mujeres y hombres migrantes. En ese quehacer utilizamos datos etnográficos provenientes de un estudio antropológico efectuado en doce comunidades del valle central de Oaxaca para argumentar que los conceptos locales de lo que ha de definir un comportamiento correcto (tanto como para los hombres como las mujeres) son fundamentales de cara a los resultados y diferencias que existen en las practicas de hombres y mujeres migrantes. [source] | |||||||||||||