2,490 research outputs found
The Amateur Sky Survey Mark III Project
The Amateur Sky Survey (TASS) is a loose confederation of amateur and
professional astronomers. We describe the design and construction of our Mark
III system, a set of wide-field drift-scan CCD cameras which monitor the
celestial equator down to thirteenth magnitude in several passbands. We explain
the methods by which images are gathered, processed, and reduced into lists of
stellar positions and magnitudes. Over the period October, 1996, to November,
1998, we compiled a large database of photometric measurements. One of our
results is the "tenxcat" catalog, which contains measurements on the standard
Johnson-Cousins system for 367,241 stars; it contains links to the light curves
of these stars as well.Comment: 20 pages, including 4 figures; additional JPEG files for Figures 1,
2. Submitted to PAS
Stratégie de prospection hydrogéologique du socle de la bordure orientale tchadienne par optimisation du nombre et de la profondeur des sondages de reconnaissance
Sous le climat à faible pluviosité du Tchad, les altérites sont dénoyées et seul le socle fracturé est aquifère. Le taux d'échec des forages atteint 60% car les fractures ont une répartition très discontinue comme le montre leur organisation fractale. Cela entraîne la coexistence de secteurs productifs et stériles. A l'échelle kilométrique, on peut ajuster le nombre de sondages de reconnaissance par village en fonction des caractéristiques climatiques, topographiques et géologiques. On définit ainsi des zones de productivité forte, où le taux de succès atteint 79%, moyenne et faible. On peut alors affecter chaque village d'un " potentiel d'investigation " qui est le produit du nombre de sondages par leur profondeur prévisionnelle.A l'échelle locale, une analyse en composantes principales des paramètres de forage montre que la présence d'eau souterraine est liée aux caractéristiques du socle fracturé et non altéré. Une analyse discriminante fournit une " équation de productivité " qui permet de prévoir 90% des résultats en cours de foration: dès que le forage a traversé une dizaine de mètres de socle non altéré, elle permet de définir une profondeur limite d'investigation dépendant des caractéristiques intrinsèques de chaque site. Elle est surtout applicable dans les zones les moins productives où l'on observe systématiquement un surcreusement inutile des forages négatifs.On dispose ainsi d'une stratégie de prospection alliant le nombre et la profondeur des forages. Elle permet de limiter la profondeur des forages implantés sur des sites peu productifs et de reporter le métré ainsi récupéré sur des sites plus prometteurs.The aim of this study is to define a new strategy for groundwater prospection in sahelian basement aquifers. At present, the number and the depth of boreholes are fixed a priori in the project document: these parameters are the same for all the villages, regardless of their environmental context. In fact, during the drilling campaign, we systematically observe a useless overdrilling of negative boreholes that affects the cumulative drilled length of the project (Table 1). This is particularly important in granitic basement areas under the low rainfall sahelian climate: water is difficult to find because of low success rates, and the driller needs to ensure no groundwater indication appears a few meters under the fatal 60 m depth. An illustration of this methodology is proposed for the Guéra, Ouaddaï and Biltine provinces of eastern Chad (Figure 1). This 150 000 km2 area is situated at the border of the Chadian basin from 10 to 15 ° north latitude at elevations of 400-700 m, with an annual rainfall between 200 and 600 mm. The geology is represented by precambrian granitoïds. Tectonics are well developed with many fractures, faults and photolineations from metric to multi-kilometric scales.In Chad, weak recharge rates imply that the weathered rock reservoir is unsaturated and the aquifer is constituted by the fractured granitic basement. Thus, the overall success rate of 500 boreholes is only 42%. The unequal distribution of fractures leads to the presence of productive and barren adjacent areas with significantly different success rates. A statistical analysis of photolineations shows their fractal distribution with a dimension around 1.57, similar to the 1.59 dimension obtained in fractal fracture models (Figure 2). Fracturation is a main component of hydrogeological knowledge in basement areas and its variations between the villages can explain the different potentials of basement productivity: we must consequently adjust an "investigation potential" depending of the characteristics of each area. The proposed strategy of prospection determines the number of boreholes to drill and their specific depth.At the kilometer scale, the total number of boreholes can be adjusted according to climatic, topographical and geological characteristics (Table 2). We show that only four parameters can explain a range of success rate from 0 to 79% in different villages (Table 3): altitude, average rainfall, petrography and fracturation intensity (measured in situ). Thus we can define the investigation potential which is the previous depth divided by the theoretical success rate of the area including the village. It is interesting to notice that the success rate in the high productivity class is similar to the average value obtained in more rainy basement countries of West Africa: for example 79% in south-west of Burkina Faso or 73% in Togo.At the local scale, a principal components analysis on 12 drilling parameters was performed. It shows that the appearance of groundwater is mainly correlated to parameters describing the unweathered fractured rocks (Figure 3). A discriminant analysis was then performed on four of these parameters: thickness of unweathered drilled basement, depth of first water arrival, number of water arrivals and hammer velocity in the unweathered basement. This yields a "productivity equation" which allows one to anticipate 90% of the borehole results (Table 4). According to this equation, we can define a maximum investigation depth based on the geological characteristics of each borehole site. The last section presents the complete strategy of groundwater basement prospection and two examples applied to Chad. For an average aquifer depth of 60 m, the investigation potential of each village depends on its productivity class: it varies theoretically from 10 boreholes (i.e. 600 m) in low productivity area to 1.3 boreholes (i.e. 76 m) in high productivity zones (Table 5). This potential must then be distributed among the different sites according to the result of their productivity equations.The village of Getgéré is situated in a particularly unproductive zone (see Table 3) where about ten boreholes are statistically needed to obtain a positive result: its investigation potential is supposed to be 300 m. Four negative boreholes were drilled from 62 to 75 m with a total depth of 261 m. In fact, the productivity equation showed all these sites were unproductive from drilled depths of 28 to 40 m deep (Table 6): the same result could have been obtained with only 130 m drilled; 131 m were uselessly consumed. With this excess drilled length, we could have drilled eight extra shallower boreholes and increased the probability of success in obtaining a productive well.The village of Eroua is situated in a productive area where the success rate is 79%: its investigation potential is 60 / 0.79=76 m. The first borehole was negative at depth of 74 m, but the productivity equation already indicated this result after only 38 m of drilling. At the second site, a positive borehole was obtained at 41 m depth where the equation foresaw 43 m. Finally, the cumulative drilled length was 115 m and the investigation strategy would have permitted the transfer of 34 m to another more promising site
Analyse des compétences professionnelles développées dans le cadre de deux enseignements : en mathématique : la proportionnalité et en français : le texte argumentatif
L'objectif de la recherche est d'identifier les compétences que les enseignants développent lorsqu'ils utilisent les Technologies de l'Information et de la Communication dans le cadre de deux enseignements particuliers : en mathématiques (enseignement de la proportionnalité : Alain Mercier & Coll.), en Français (enseignement du "texte" argumentatif : Anne Gombert & Coll.). Le choix de ces deux types d'enseignement résulte du fait : (a) qu'ils jalonnent le cursus scolaire des enfants de la maternelle à la terminale (b) qu'ils concernent la transmission d'un savoir disciplinaire (notions ou concepts à transmettre) et transversal (savoir-faire ou compétence acquise et réutilisable hors champ disciplinaire).Cette recherche, en bout de course, devrait permettre :1 - d'identifier l'impact des TIC sur les gestes professionnels des deux enseignements étudiés,2 - de rendre compte des contraintes liées au dispositif informatique et décrire leurs usages réel
Transparency and Development
Today, many organisations in the development sector stress a link from transparency to “improved accountability, increased aid effectiveness and better value for money” (Beech, 2011, “Aid Transparency: The future of Aid is changing”). In particular, the Aid Transparency Movement, which emerged with the High Level Forum on Harmonization in 2003, is meant to improve the effectiveness of official aid. As this Movement and the first ‘Open Data for Development’ conference held in Amsterdam in May 2011 convey, the issue of transparency for development opens up a new sphere for critical thought on alternative approaches to development aid and on the conception of development as such. The development sector currently witnesses a momentum prone to change of aid practices triggered by the “new global standard” of what they call ‘aid transparency’ (ibid.). Aid Transparency is the presumed key to achieve aid effectiveness and correspondingly better development results. Moreover, some development workers suggest that aid transparency could revolutionize development in the sense of dissociating any negative perception of development and endow the concept with a positive connotation instead. Against this background, this article poses the question, does aid transparency really make aid more effective and revolutionize development
Sialocoele associated with the molar salivary gland in a British Shorthair cat
Case summary A 16-year-old neutered female British Shorthair cat presented with a 5-year history of swelling lateral to the left mandible that intermittently discharged viscous, clear fluid from a small defect in the skin. CT, ultrasonography, physical characteristics and cytology of the fluid were suggestive of sialocoele. CT showed a large, cavitary, fluid-filled mass lateral to the left mandible. A ventral approach was used to resect the left mandibular, sublingual and molar salivary glands and sialocoele. Histopathology of the molar and mandibular and sublingual glands showed chronic active sialoadenitis with more severe changes in the molar gland. There were no signs of recurrence of the sialocoele 12 months after surgery. Relevance and novel information This is the first report of a cranial cervical sialocoele potentially involving the molar salivary gland in a cat. Resection of the mandibular, sublingual and molar salivary glands should be considered in cats that present with a cranial cervical sialocoele
Analyse des compétences professionnelles développées dans le cadre de deux enseignements : en mathématique : la proportionnalité et en français : le texte argumentatif
L'objectif de la recherche est d'identifier les compétences que les enseignants développent lorsqu'ils utilisent les Technologies de l'Information et de la Communication dans le cadre de deux enseignements particuliers : en mathématiques (enseignement de la proportionnalité : Alain Mercier & Coll.), en Français (enseignement du "texte" argumentatif : Anne Gombert & Coll.). Le choix de ces deux types d'enseignement résulte du fait : (a) qu'ils jalonnent le cursus scolaire des enfants de la maternelle à la terminale (b) qu'ils concernent la transmission d'un savoir disciplinaire (notions ou concepts à transmettre) et transversal (savoir-faire ou compétence acquise et réutilisable hors champ disciplinaire).Cette recherche, en bout de course, devrait permettre :1 - d'identifier l'impact des TIC sur les gestes professionnels des deux enseignements étudiés,2 - de rendre compte des contraintes liées au dispositif informatique et décrire leurs usages réel
Contradictions between Wanting to and Being Able to Practice Food Shopping: The Experiences of Vulnerable Young People in the North East of Scotland
In the context of the rise in numbers of people affected by food poverty in the UK the Foodways and Futures 2013-2016 project explores the ways in which vulnerable young people 16-25 experience their relationship to food In my data analysis the experience of shopping for food emerged as a particularly pertinent issue for young people although this remains largely unexplored in the literature I found that among other issues food shopping is not necessarily an enjoyable experience for vulnerable young people some of whom are anxious about entering food shops and engage in hurried shopping practices Decision-making was based on budget restrictions as well as the immediate experience of hunger As a result food shopping was often rapid and reactive This vulnerable group of food shoppers do not necessarily purchase the cheapest items as these may be seen as degrading to self-esteem Young people also faced physical obstacles of distances to the larger shops and the weight of their food shopping Strongly opposed to public health expectations on healthy eating I found contradictions in how young people wanted to behave when purchasing foods and how they were able to practice their food shop Drawing on and extending Bourdieu s work on habitus I aim to make sense of these accounts and show that rather than being deviant the study participants adapt to an unequal distribution of resource
Viviane Baeke, Le temps des rites. Ordre du monde et destin individuel en pays wuli (Cameroun). Paris, Société d’ethnologie, 2004, 471 p., illustr., bibliogr., index.
From “learning to use” towards “using to learn”? : long-term effects of structure-based versus dynamic usage-based programs for French
Over the past 50 years, the Communicative Language Teaching (CLT) approach has come to dominate foreign language teaching practices in the world. This approach originated in the 1970s and was seen as an important tool for the integration of citizens in the member states of the European Union. Despite its communicative intentions, however, common CLT practice has remained predominantly structure-based with explicit grammar instruction and a focus on written skills (reading and writing). It is difficult for oral skills to develop satisfactorily in such a structure-based program. In the Netherlands, a number of factors have reinforced this focus on written skills: (1) the big educational reforms in the 1990s with a strong emphasis on active and independent learning, (2) the central role of commercial coursebooks in foreign language teaching practice (partly as a result of the first factor) and (3) the final exams, which test only reading skills, and have led foreign language teachers to spend a lot of time on the development of reading skills. This study has shown that a dynamic usage-based approach, in which exposure and practice are the focus, learners learn to understand and speak the language much more fluently than their structure-based peers. We also found that they do not seemingly fall behind when it comes to grammatical accuracy and reading skills. We make a strong case for the implementation of more such methods in the Dutch foreign language classroom
Virtue and Modern Society
Virtue is a word not often used in the modern America. Even if it were used, it would be so misused that it would not be worth using the word. If asked, the average person on the street might tell you that virtue is an old-fashioned way of saying that someone is a good person or a good citizen – the sort of person who picks up litter in the park or volunteers for a charity. This understanding, however, is miles from the real richness of the word
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