Estudio cuantitativo de la erosion confines de proteccion de los suelos : las parcelas de Alangasi e Ilalo

Pour étudier les acpects quantitatifs de l'érosion hydrique, 7 parcelles de ruissellement de 50 m2 de surface ont été installées en divers lieux de la Sierra volcanique de l'Equateur. Parmi les premiers résultats obtenus on peut retenir d'une part le rôle considérable des précipitations par leurs intensités, et d'autre part l'importance des poids de terre perdue sur parcelles cultivées, qui peuvent fluctuer pour les plus volumineux entre 210 et 490 tonnes/hectare/année. (Résumé d'auteur

Terres d'altitude, terres de risque : la lutte contre l'érosion dans les Andes équatoriennes

L'Equateur est un pays montagneux et volcanique, représentatif de la cordillère des Andes dans son segment situé entre les tropiques. La montagne, appelée "Sierra", présente une situation singulière : à la suite d'un processus de réforme agraire aux résultats contestables, un grand nombre de petits paysans ont été déplacés vers les versants et les hautes terres, qui portent un damier formé de nombreuses petites parcelles de cultures faiblement productives, le minifundio. Cet agrosystème d'altitude favorise l'accélération de l'érosion des sols, dans un milieu montagnard où ce type de risque est naturellement élevé. Le petit paysannat du minifundio est confronté à une érosion très active qui affecte ses potentialités alimentaires. L'absence de mesures antiérosives efficaces et adaptées au contexte socio-économique du paysannat concerné pénalise fortement la durabilité de l'agrosystème. Pour lutter contre l'érosion de ces terres, un programme de recherche en coopération accordant une large place à la participation du paysannat et associant recherche cognitive et application a été mise en oeuvre par le ministère équatorien de l'Agriculture et l'IRD suivant trois phases complémentaires. La phase initiale, qualitative et spatiale, pose les principaux éléments de diagnostic de la situation érosive de la Sierra équatorienne. Elle fait apparaître l'action prédominante du ruissellement concentré, notamment dans les parties nord et centre de la Sierra, où les sols ou andosols sont dérivés de matériaux volcaniques. L'affleurement en surface de la "cangahua", une formation composée d'horizons indurés, est révélateur de l'extension de l'érosion... (D'après résumé d'auteur

New Antenna Deployment, Pointing and Supporting Mechanism

On ITALSAT Flight 2, the Italian telecommunications satellite, the two L-Ka antennas (Tx and Rx) use two large deployable reflectors (2000-mm diameter), whose deployment and fine pointing functions are accomplished by means of an innovative mechanism concept. The Antenna Deployment & Pointing Mechanism and Supporting Structure (ADPMSS) is based on a new configuration solution, where the reflector and mechanisms are conceived as an integrated, self-contained assembly. This approach is different from the traditional configuration solution. Typically, a rigid arm is used to deploy and then support the reflector in the operating position, and an Antenna Pointing Mechanism (APM) is normally interposed between the reflector and the arm for steering operation. The main characteristics of the ADPMSS are: combined implementation of deployment, pointing, and reflector support; optimum integration of active components and interface matching with the satellite platform; structural link distribution to avoid hyperstatic connections; very light weight and; high performance in terms of deployment torque margin and pointing range/accuracy. After having successfully been subjected to all component-level qualification and system-level acceptance tests, two flight ADPMSS mechanisms (one for each antenna) are now integrated on ITALSAT F2 and are ready for launch. This paper deals with the design concept, development, and testing program performed to qualify the ADPMSS mechanism

Pembelajaran Bahasa Inggris Untuk Para Siswa Sekolah Dasar Di Rumah Belajar Sosial

The implementation of community service aimed at improving the English proficiency of the students in study house. The methods applied in this training were the provision of materials and practice. The provision of materials was the provision of guidance and explanation of the theory of English. After that, the teacher gave the questions and asked the students to do and practice dialogue in English. There were two study houses namely home study in Sido Rahayu and in Pandan Landung. The results of the activities were: at Sido Rahayu home study: 100% students always came and followed the activities held twice a week. 90% students understood the material and could work on the questions given by the teacher in writing. 80% students could do independently and could do a conversation.At Pandan Landung home study: 100% students always actively came. 75% students really understood the material and could work on the questions in writing. 6o% students could do independently the problems given by teachers and could do a simple conversation

Determination of Volatile Organic Compounds (VOCs) from wrapping films and wrapped PDO Italian cheeses by using HS-SPME and GC/MS

Nowadays food wrapping assures attractive presentation and simplifies self-service shopping. Polyvinylchloride (PVC)- And polyethylene (PE)-based cling-films are widely used worldwide for wrapping cheeses. For this purpose, films used in retail possess suitable technical properties such as clinginess and unrolling capacity, that are achieved by using specific plasticizers during their manufacturing process. In the present study, the main VOCs of three cling-films (either PVC-based or PE-based) for retail use were characterized by means of Solid-Phase Micro-Extraction and GC/MS. In addition, the effects of cling film type and contact time on the migration of VOCs from the films to four different PDO Italian cheeses during cold storage under light or dark were also investigated. Among the VOCs isolated from cling-films, PVC released 2-ethylhexanol and triacetin. These compounds can likely be considered as a "non-intentionally added substance". These same compounds were also detected in cheeses wrapped in PVC films with the highest concentration found after 20 days storage. The PE cling-film was shown to possess a simpler VOC profile, lacking some molecules peculiar to PVC films. The same conclusions can be drawn for cheeses wrapped in the PE cling-film. Other VOCs found in wrapped cheeses were likely to have been released either by direct transfer from the materials used for the manufacture of cling-films or from contamination of the films. Overall, HS-SPME is shown to be a rapid and solvent free technique to screen the VOCs profile of cling-films, and to detect VOCs migration from cling-films to cheese under real retail storage conditions

Streptococcus thermophilus urease activity boosts Lactobacillus delbrueckii subsp. bulgaricus homolactic fermentation

The proto-cooperation between Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus in the yogurt consortium enhances the growth rate and size of each population. In contrast, the independent growth of the two species in milk leads to a slower growth rate and a smaller population size. In this study, we report the first evidence that the urease activity of S. thermophilus increases the intracellular pH of L. delbrueckii in the absence of carbon source. However, in milk, in the presence of lactose the alkalizing effect of urea-derived ammonia was not detectable. Nevertheless, based on glucose consumption and lactic acid production at different pHin, L. delbrueckii showed an optimum of glycolysis and homolactic fermentation at alkaline pH values. In milk, we observed that ammonia provided by urea hydrolysis boosted lactic acid production in S. thermophilus and in L. delbrueckii when the species were grown alone or in combination. Therefore, we propose that urease activity acts as an altruistic cooperative trait, which is costly for urease-positive individuals but provides a local benefit because other individuals can take advantage of urease-dependent ammonia release

Nanopatterned Self-Assembled Monolayers by Using Diblock Copolymer Micelles as Nanometer-Scale Adsorption and Etch Masks

Nanopatterned self-assembled monolayers (SAMs) are obtained from a simple, straight-forward procedure by using masks derived from monolayers of block copolymer micelles. The nanopatterned SAMs consist of regularly spaced circular hydrophilic areas with diams. of approx. 60 nm on a continuous hydrophopic background or vice versa. The surfaces are shown to be excellent tools for the prepn. of arrays of nanocrystal