Student perspectives on the relationship between a curve and its tangent in the transition from Euclidean Geometry to Analysis

The tangent line is a central concept in many mathematics and science courses. In this paper we describe a model of students’ thinking – concept images as well as ability in symbolic manipulation – about the tangent line of a curve as it has developed through students’ experiences in Euclidean Geometry and Analysis courses. Data was collected through a questionnaire administered to 196 Year 12 students. Through Latent Class Analysis, the participants were classified in three hierarchical groups representing the transition from a Geometrical Global perspective on the tangent line to an Analytical Local perspective. In the light of this classification, and through qualitative explanations of the students’ responses, we describe students’ thinking about tangents in terms of seven factors. We confirm the model constituted by these seven factors through Confirmatory Factor Analysis

Morbidité et létalité palustres dans un service de pédiatrie en Afrique de l'Ouest

Le paludisme est à l'origine de 30 % des hospitalisations dans le service de pédiatrie de l'hôpital de Bobo-Dioulasso (Burkina Faso), avec une grande variation de fréquence au cours de l'année : 11 % des hospitalisations en saison sèche, 43 % en période de transmission palustre. Avec un taux de létalité de 7 %, le paludisme est directement responsable de 15 % des décès des enfants hospitalisés. (Résumé d'auteur

Reducing the oral quinine-quinidine-cinchonin (Quinimax) treatment of uncomplicated malaria to three days does not increase the recurrence of attacks among children living in a highly endemic area of Senegal

A 3 d shortened course of the quinine-quinidine-cinchonin association Quinimax (trademark) was compared to the usual 7 d regimen for routinely treating 462 acute uncomplicated #Plasmodium falciparum$malaria attacks in 72 children under the age of 10 years in Dielmo, a holoendemic village in Senegal. 25 mg/kg Quinimax (trademark) salt daily, given in 3 equal doses, improved clinical status in 99.6$ and the partial acquired immunity of the children were probably responsible for the absence of any difference between the courses. Oral Quinimax (trademark) for 3 d is a possible alternative regimen to chloroquine and sulfadoxine-pyrimethamine for treating uncomplicated malaria in highly endemic areas of Africa where clinical resistance to these drugs exists. (Résumé d'auteur

Who gets the information? Gender, power and equity considerations in the design of climate services for farmers

Central to understanding the usefulness of climate and weather forecasts in support of agricultural decision-making is addressing the issue of who receives what information. Many contend that improved climate forecasts since the late 1990s have had limited impact on smallholder farming communities in Africa and across the developing world. However, power and privilege may determine who has access to appropriate climate and advisory services within those communities. In 2011-2012, we tested this hypothesis in three climate-vulnerable farming communities in the CGIAR Research Program on Climate Change, Agriculture and Food Security semi-arid research site of Kaffrine, Senegal. Therein, we assessed gender-specific vulnerabilities to climate-related shocks, endogenous adaptation strategies, and coping mechanisms. From the gap between vulnerability and local capacity, we deduced farmers’ climate service needs, and then assessed whether these systematically differed between distinct vulnerable sub-groups within the community – chiefly, between male and female farmers. In 2011 we introduced a seasonal climate forecast for the first time in the community, and explored perceptions of forecast access, usefulness and value, by both men and women

Scaling up climate services for farmers: Mission Possible. Learning from good practice in Africa and South Asia

This report presents lessons learned from 18 case studies across Africa and South Asia that have developed and delivered weather and climate information and related advisory services for smallholder farmers. The case studies and resulting lessons provide insights on what will be needed to build effective national systems for the production, delivery, communication and evaluation of operational climate services for smallholder farmers across the developing world. The case studies include two national-scale programmes that have been the subject of recent assessments: India’s Integrated Agrometeorological Advisory Service (AAS) Program, which provides tailored weather-based agrometeorological advisories to millions of farmers; and Mali’s Projet d’Assistance Agro-meteorologique au Monde Rural, which provided innovative seasonal agrometeorological advisory services for smallholder farmers and 16 less mature initiatives operating at a pilot scale across Africa and South Asia. The case studies were examined from the standpoint of how they address five key challenges for scaling up effective climate services for farmers: salience, access, legitimacy, equity and integration

The cetaceans of Guinea, a first check-list of documented species. Scientific Committee document SC/58/O15, International Whaling Commission, May-June 2006, St. Kitts

A CMS workshop on West African Cetacea (Conakry, May 2000), called for i.a. ‘carrying out .. inventory of cetacean species; collection, treatment and compilation of data for each state.’ The present paper is a preliminary faunal checklist of cetaceans occurring in Guinea’s EEZ. Information was gleaned from strandings, bycatches, scientific and opportunistic sightings and a literature review. Ten species are included for which supporting voucher material and data were available for examination. These are, three baleen whales: Balaenoptera brydei, Balaenoptera acutorostrata and Megaptera novaeangliae; and seven species of odontocetes: Kogia breviceps, Tursiops truncatus, Sousa teuszii, Stenella frontalis, Delphinus delphis, Steno bredanensis and Globicephala macrorhynchus. Another two species, Physeter macrocephalus and Stenella attenuate were sighted off Guinea but no photographic evidence was obtained. The current account is thought to reflect an incomplete picture of Guinea’s cetacean biodiversity. Future surveys are expected to update and investigate spatial and temporal distribution patterns for each species along Guinea’s coast. A few bycatches landed by artisanal fishers were utilised locally, but there are no signs of any substantial captures. Nonetheless, monitoring should be continued. The set-up of a national reference collection and database is recommended. The population identities of the encountered Atlantic humpback dolphin, minke whale and humpback whale are of particular interest

Clinical and pathological kidney aspects of sickle cell anemia at Dakar: study of 11 cases of renal biopsies

Few studies are devoted to the practice of renal biopsy in sickle cell nephropathy; our objective was to determine the histological and evolutionary patterns of renal lesions in sickle cell patients who underwent renal biopsy in Dakar.Methods:This was a retrospective multicentric study (conducted from December 2009 to August 2011) on renal biopsies performed on sickle cell anaemic patients at the Nephrology Department of Teaching Hospital Aristide Le Dantec and the Albert Royer Childrens Hospital. The histological, therapeutic and evolutionary data were analysed.From the 292 total renal biopsies, 11 (3.80%) were performed on sickle cell patients (6SS, 1SBth + 4 AS) with a mean age of 23.1 [13-51 years]. Nephrotic syndrome was the indication of renal biopsy in all cases. Focal segmental glomerulosclerosis was the most frequent histological finding (five cases), followed by a combination of various specific lesions (hypertrophy of glomerular and peritubular capillaries), minimal glomerular lesions (three cases), membranoproliferative glomerulonephritis (two cases) and extra-membranous glomerulonephritis (one case). Complete remission after treatment was achieved in seven cases and one patient expired. Three patients did not continue with follow-up appointments.Conclusions:Renal biopsy is not very frequent in the course of sickle cell anaemia and in most cases it is performed because of nephrotic syndrome. The histological findings are diverse with a predominance of focal segmental glomerulosclerosis

HIV infection and severe malnutrition: a clinical and epidemiological study in Burkina Faso.

OBJECTIVE: To define a clinical profile indicative of HIV infection in a population of severely malnourished children in Burkina Faso. A total of 433 children (average age, 19 months) were recruited at the Sanou Souro National Hospital, Bobo Dioulasso, Burkina Faso. RESULTS: Sixty-three per cent presented with marasmus, 13% with kwashiorkor and 24% with both forms of malnutrition. The prevalence of HIV infection in children aged over 12 months was 13.8%, with a marked predominance of HIV-1 (95.8%). Mother-to-child transmission was proven in 77% of the cases; in 10% of the observed paediatric AIDS cases, transmission may have occurred through multi-injections with contaminated equipment. Marasmus was the form of malnutrition most frequently associated with HIV (P < 0.001); its severity was exacerbated by HIV infection. Adenopathy (P < 0.0001), oral candidiasis (P < 0.0006), skin disorders (P < 0.01) and hepatomegaly (P = 0.01) appeared to be significantly related to HIV infection. Discriminant analysis revealed that the presence of adenopathies was the strongest indicator symptom of HIV infection. Multivariate analysis revealed that a clinical profile of marasmus, adenopathies and oral candidiasis (specificity, 82%) was indicative of HIV infection in this population. The short-term clinical prognosis was poor and usually led to the death of the child when seropositive (P < 0.001). CONCLUSIONS: Among children exhibiting severe malnutrition, HIV-positive children are distinguished by a high horizontal transmission rate, a high specific clinical profile and a very poor prognosis