Chemical and pharmacological investigation of Solanum species of Brazil: a search for solasodine and other potentially useful therapeutic agents

A systematic search for solasodine, an important staring material for the partial synthesis of steroidal hormones as well as other potentially bioactive constituents of various Solanum species of Brazil has been undertaken. Thus, the fruits of S. paludosum, S. asperum, S. sessiliforum and Solanum sp. were found to contain significant amounts of solasodine. The root bark of S. paludosum which showe durare like activity yelded tomatidenol and another yet unidentified alkaloid responsible for the biological activity. The fruits of S. asperum yelded a new spirosolane alkaloid, solaparnaine. The stem bark of S. pseudo-quina showed convulsive and exitatory activity from which (25S)-isosolafloridine was identified as the active principle. In addition, the latter alkaloid was also found to show antimicrobial activity.

Teacher strategies to elicit knowledge from students in the CLIL classroom: the purpose of questions in controlled patterns of teacher-student interaction

This Master Dissertation comprises two parts: a personal reflection and an empirical study. The personal reflection reviews the process of professionalization undergone by its author throughout the Master. The empirical study tackles teacher strategies to elicit knowledge from students in the CLIL classroom and more specifically the purpose of questions in controlled patterns of teacher-student interaction. The theories of relevant authors such as Vigotsky, Mercer and Tsui are used as a framework to analyze the data presented. The analysis shows the different strategies to elicit knowledge used by the teacher and the appropriateness of her questions in the analyzed interaction

The first steps of a secondary school teacher: experiences and studies of a student-teacher

This dissertation aims at fostering the professional development of the EFL teacher. This document compiles two small scale empirical studies carried out during the practicum periods of the TED's course. The first one is based on the role of the teacher's talk in the EFL classroom and the second one focuses on students’ small group talk, analysing the impact of cooperative learning in the EFL classroom by examining students' conversation. The following section gathers the teacher's personal reflections upon the process of professionalization. The paper concludes with a summary of the major findings and further professional improvement proposals

Physicians' attitudes towards prevention: importance of intervention-specific barriers and physicians' health habits.

BACKGROUND: Several studies have explored physicians' attitudes towards prevention and barriers to the delivery of preventive health interventions. However, the relative importance of these previously identified barriers, both in general terms and in the context of a number of specific preventive interventions, has not been identified. Certain barriers may only pertain to a subset of preventive interventions. OBJECTIVES: We aimed to determine the relative importance of identified barriers to preventive interventions and to explore the association between physicians' characteristics and their attitudes towards prevention. METHODS: We conducted a cross-sectional survey of 496 of the 686 (72.3% response rate) generalist physicians from three Swiss cantons through a questionnaire asking physicians to rate the general importance of eight preventive health strategies and the relative importance of seven commonly cited barriers in relation to each specific preventive health strategy. RESULTS: The proportion of physicians rating each preventive intervention as being important varied from 76% for colorectal cancer screening to 100% for blood pressure control. Lack of time and lack of patient interest were generally considered to be important barriers by 41% and 44% of physicians, respectively, but the importance of these two barriers tended to be specifically higher for counselling-based interventions. Lack of training was most notably a barrier to counselling about alcohol and nutrition. Four characteristics of physicians predicted negative attitudes toward alcohol and smoking counselling: consumption of more than three alcoholic drinks per day [odds ratio (OR) = 8.4], sedentary lifestyle (OR = 3.4), lack of national certification (OR = 2.2) and lack of awareness of their own blood pressure (OR = 2.0). CONCLUSIONS: The relative importance of specific barriers varies across preventive interventions. This points to a need for tailored practice interventions targeting the specific barriers that impede a given preventive service. The negative influence of physicians' own health behaviours indicates a need for associated population-based interventions that reduce the prevalence of high-risk behaviours in the population as a whole.

Local and global consistency properties for student placement

In the context of resource allocation on the basis of priorities, Ergin (2002) identifies a necessary and sufficient condition on the priority structure such that the student-optimal stable mechanism satisfies a consistency principle. Ergin (2002) formulates consistency as a local property based on a fixed population of agents and fixed resources -- we refer to this condition as local consistency and to his condition on the priority structure as local acyclicity. We identify a related but stronger necessary and sufficient condition (unit acyclicity) on the priority structure such that the student-optimal stable mechanism satisfies a more standard global consistency property. Next, we provide necessary and sufficient conditions for the student-optimal stable mechanism to satisfy converse consistency principles. We identify a necessary and sufficient condition (local shift-freeness) on the priority structure such that the student-optimal stable mechanism satisfies local converse consistency. Interestingly, local acyclicity implies local shift-freeness and hence the student-optimal stable mechanism more frequently satisfies local converse consistency than local consistency. Finally, in order for the student-optimal stable mechanism to be globally conversely consistent, one again has to impose unit acyclicity on the priority structure. Hence, unit acyclicity is a necessary and sufficient condition on the priority structure for the student-optimal stable mechanism to satisfy global consistency or global converse consistency.

Line search multilevel optimization as computational methods for dense optical flow

We evaluate the performance of different optimization techniques developed in the context of optical flowcomputation with different variational models. In particular, based on truncated Newton methods (TN) that have been an effective approach for large-scale unconstrained optimization, we develop the use of efficient multilevel schemes for computing the optical flow. More precisely, we evaluate the performance of a standard unidirectional multilevel algorithm - called multiresolution optimization (MR/OPT), to a bidrectional multilevel algorithm - called full multigrid optimization (FMG/OPT). The FMG/OPT algorithm treats the coarse grid correction as an optimization search direction and eventually scales it using a line search. Experimental results on different image sequences using four models of optical flow computation show that the FMG/OPT algorithm outperforms both the TN and MR/OPT algorithms in terms of the computational work and the quality of the optical flow estimation.

Mosquito Frequency and Feeding Habits in an Enzootic Canine Dirofilariasis Area in Niterói, State of Rio de Janeiro, Brazil

Heartworm, a chronic fatal mosquito-borne canine disease, is frequently diagnosed in dogs from the State of Rio de Janeiro, where its prevalence is 29.7% in the city of Niterói. Nevertheless it is rarely detected in cats (0.8%) from the same state. Dogs are the primary source of infection to mosquitoes, because cats either do not demonstrate microfilaremia or it is too low and transient for transmission. A mosquito survey was conducted in Itacoatiara, Niterói, from March 1995 to February 1996, using canine, feline and human baits. A total of 21 mosquito species (3,888 females) was collected and biting frequency was highest at dusk. The four species collected most frequently (88.9%) were: Aedes taeniorhynchus (30% of the total catch; with the peak in May/June); Culex quinquefasciatus (22.5%; August/October); Aedes scapularis (19.4%; August, October/November and January) and Culex declarator (17%; November/January). Human baits were attractive to these species and dogs were significantly more attractive to them than cats. Ae. taeniorhynchus, Cx. quinquefasciatus, Ae. scapularis, Cx. declarator and Cx. nigripalpus are the most likely mosquito species to transmit Dirofilaria immitis parasites to dogs and may transmit the parasite to humans. It is also suggested that the vector to cats belongs to the genus Culex

Molecular characterisation of intermediate snail hosts and the search for resistance genes

The relationship between schistosomes and their intermediate hosts is an extremely intricate one with strains and species of the parasite depending on particular species of snail, which in turn may vary in their susceptibility to the parasites. In order to gain a better understanding of the epidemiology of the disease we have been investigating the use of molecular markers for snail identification and for studying host-parasite relationships. In this paper we will draw on examples concerning schistosomiasis in West and East Africa to illustrate how a molecular analysis can be used as part of a "total evidence" approach to characterisation of Bulinus species and provide insights into parasite transmission. Particular emphasis is given to ribosomal RNA genes (rRNA), random amplified polymorphic DNA (RAPDs) and the mitochondrial gene cytochrome oxidase I (COI). Snails resistant to infection occur naturally and there is a genetic basis for this resistance. In Biomphalaria glabrata resistance to Schistosoma mansoni is known to be a polygenic trait and we have initiated a preliminary search for snail genomic regions linked to, or involved in, resistance by using a RAPD based approach in conjunction with progeny pooling methods. We are currently characterising a variety of STSs (sequence tagged sites) associated with resistance. These can be used for local linkage and interval mapping to define genomic regions associated with the resistance trait. The development of such markers into simple dot-blot or specific PCR-based assays may have a direct and practical application for the identification of resistant snails in natural populations.

Studies on populations of Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera: Psychodidae: Phlebotominae) in Brazil

Studies were performed on five Brazilian populations of Lutzomyia longipalpis: Salvaterra (PA), São José do Ribamar (MA), Canindé (CE), Natal (RN) and Gruta da Lapinha, Lagoa Santa (MG). No morphological differences were observed that could distinguish between these populations. Homogeneity tests showed that the allopatric populations display a certain heterogeneity and that the sympatric populations, with different patterns of spots, are homogeneous. The Student-Newman-Keuls test, represented by Euler-Venn diagrams, showed a disjunction between the populations from the north/northeast and the one from Gruta da Lapinha. Genetic distances between the four populations (excluding the Canindé population) were within the range of intrapopulational differences. The Gruta da Lapinha population displayed a heterozygotic deficiency that could be a consequence of high levels of inbreeding due to cryptic habits of living in a small cave. These results do not favor the hypothesis of a L. longipalpis species complex in Brazil, and the species should be considered high polymorphic.

Report of Student Support Review

Report of Student support review

Student Support Determination 07-08 (PDF 167 KB)

Financial support arrangements in the 2007/08 academic year for Allied Health Professional Students and Medical and Dental students from year five study