Animal organ dissections in high schools : is there more than just cutting?

In Life Sciences education internationally, including South Africa, the study of animal and organ morphology has traditionally involved dissections since the early nineteenth century. The major purpose of this study was to investigate how the engagement of learners with animal organ dissections may influence the development of problem-solving skills and how teachers use animal dissections to develop these skills of Grade 11 learners in Life Sciences (Biology) education. A mixed-methods research design was used for this study. Data were collected from a pre-test and a post-test (which had predominantly problem-solving questions), a learner questionnaire, lesson observations and teacher interviews. Tests and questionnaires were administered to 224 Grade 11 Life Sciences learners. Six Grade 11 Life Sciences teachers at four high schools from different environments participated in the study. The pre-test and post-test scores were compared using a parametric matched t-test. The comparison for the five cognitive levels including rote learning and problem-solving as well as the total calculation were all highly significant with p-values <0.0001. The learners’ responses in the questionnaire and the teachers’ responses during the interviews indicate their acknowledgement that animal organ dissection may be used to develop problem-solving skills. The results show that there is more to animal organ dissection than just cutting and drawing; it may be used as a problem-solving teaching strategy. The level of learner engagement with animal organ dissections can determine the level of development of problem-solving skills. This study recommends that teachers should be encouraged to link animal organ dissections to specific anatomical and physiological problems where applicable, and to allow learners to solve these problems when performing the dissections; they should not merely let the learners cut, draw and label the organ.http://www.tandfonline.com/loi/rmse202016-06-03am201

Isolation and identification of a South African lentivirus from jaagsiekte lungs

In the course of attempts to grow the jaagsiekte retrovirus in cell culture, a typical lentivirus was isolated for the first time in South Africa from adenomatous lungs. Morphologically the virus could not be distinguished from other lentiviruses, but serologically it was shown to be more closely related to visna virus than to caprine arthritis-encephalitis virus. However, a preliminary restriction enzyme analysis of the linear proviral DNA of this new lentivirus (SA-DMVV) revealed that it is significantly district from visna virus and CAEV and therefore may represent a third type of lentivirus. Antibodies to the virus were demonstrated in a number of sheep in various parts of the country, but a direct link to a disease condition was not found. Attempts to produce lung lesions by intratracheal injection of the virus have been unsuccessful to date but a transient arthritis was produced by intra-articular inoculation. Viral replication seems to be enhanced in jaagsiekte lungs.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

The Giant Pacific Oyster (Crassostrea gigas) as a modern analog for fossil ostreoids: Isotopic (Ca, O, C) and elemental (Mg/Ca, Sr/Ca, Mn/Ca) proxies

Modern analogs are an essential part of palaeoclimate studies, because they provide the basis for the understanding of geochemical signatures of fossils. Ostreoids are common in many sedimentary sequences and because of their fast growth, high temporal resolution sampling of past seasonal variability is possible. Here, two shell structures of modern Giant Pacific Oysters (Crassostrea gigas), the chalky substance and foliate layers, have been sampled for trace element distributions (Mg, Sr, Mn) and stable isotope variability (C, O, Ca). Oxygen isotopes exhibit a clear seasonal signature. Mean carbon isotope values of different oysters agree within 0.1‰, but ontogenic variability is complicated by shell growth patterns and potential small vital effects. The calcium isotope ratios are found to be constant throughout ontogeny within analytical precision at a value of δ44/40Ca = 0.68 ± 0.16‰ (2 sd) SRM–915a which is consistent with other bivalve species. Calcium isotope ratios in oyster shell material might thus be a possible proxy for palaeo seawater calcium isotope ratios. Element/Ca ratios are significantly higher in the chalky substance than in the foliate layers and especially high Sr/Ca and Mn/Ca ratios are observed for the first growth season of the oysters. Mg/Ca ratios in the chalky substance show a negative correlation with δ18O values, compatible with a temperature dependence, whereas this correlation is absent in the foliate layers. Seasonal changes of Sr/Ca are controlled by metabolic processes, whereas for Mn/Ca an additional environmental control is evident

Prospective biology teachers' attitudes toward animal dissection : implications and recommendations for the teaching of biology

A sample of 242 prospective biology teachers at a South African university responded to a questionnaire on animal dissection in a science-related context. The students were required to answer questions relating to their experiences and attitudes toward animal dissection. The influence of gender, culture, and religion on their attitudes is discussed. The implications of the findings for teaching biological science are considered and a number of recommendations are made in regard to animal dissection in the biology classroom

Klinisch-biomedizinische Forschung an ausseruniversitaeteren Einrichtungen. Teilvorhaben: Die Rolle von Virus-Infektionen und molekular genetische Veraenderungen von Harnblasentumoren Abschlussbericht

SIGLEAvailable from TIB Hannover: DtF QN1(62,59) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman