Atmospheric carbon dioxide/oxygen imbalance in the late Cretaceous, hatching of eggs and the extinction of biota

Main articleA new theory explains why dinosaurs, pterosaurs and large avian species like Hesperornis became extinct at the end of the Cretaceous while mammals, smaller Cretaceous birds, crocodiles, chelonians and saurians survived . An atmospheric carbon dioxide/oxygen imbalance at the end of the Cretaceous caused by kimberlite volcanism, basalt flows and a reduction in oxygen production by marine phytoplankton is proposed. The unfavourable area to volume ratio of large eggs for diffusion of respiratory gases compared to that of small eggs resulted in the asphyxiation of the embryos of large endothermic egg laying groups. Endothermic species, e.g. dinosaurs that covered their eggs with soil, restricted the free circulation of air and would have been first to become extinct. Smaller ectothermic species, e.g. crocodiles, chelonians and saurians with lower embryonic respiratory requirements and endothermic species like the birds that did not cover their eggs, survived.Non

A new record for Ptenopus (Reptilia: Gekkonidae) from calitzdorp

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Eating for 1, Healthy and Active for 2; feasibility of delivering novel, compact training for midwives to build knowledge and confidence in giving nutrition, physical activity and weight management advice during pregnancy

Gold OABackground: Women in Wales are more likely to be obese in pregnancy than in any other United Kingdom (UK) country. Midwives are ideally placed to explore nutrition, physical activity and weight management concerns however qualitative studies indicate they lack confidence in raising the sensitive issue of weight. Acknowledging this and the reality of finite time and resources, this study aimed to deliver compact training on nutrition, physical activity and weight management during pregnancy to increase the knowledge and confidence of midwives in this subject. Methods A compact training package for midwives was developed comprising of evidence based nutrition, physical activity and weight management guidance for pregnancy. Training was promoted via midwifery leads and delivered within the Health Board. Questionnaires based on statements from national public health guidance were used to assess changes in self-reported knowledge and confidence pre and post training. Descriptive statistics were applied and 95% confidence intervals were calculated. Results 43 midwives registered for training, 32 (74%) attended and completed the questionnaires. Although, pre training knowledge and confidence varied between participants, statistically significant improvements in self-reported knowledge and confidence were observed post training. 97% indicated knowledge of pregnancy specific food and nutrition messages as ‘better’ (95% CI 85 to 100), as opposed to 3% stating ‘stayed the same’ – 60% stated ‘much better’. 83% indicated confidence to explain the risks of raised BMI in pregnancy was either ‘much’ or ‘somewhat better’ (95% CI 66 to 93), as opposed to 17% stating ‘stayed the same’. 89% indicated confidence to discuss eating habits and physical activity was ‘much’ or ‘somewhat better’ (95% CI 73 to 97) as opposed to 11% stating ‘stayed the same’. Emergent themes highlighted that training was positively received and relevant to midwifery practice. Conclusions This study provides early indications that a compact nutrition, physical activity and weight management training package improves midwives self-reported knowledge and confidence. Cascading training across the midwifery service in the Health Board and conducting further studies to elicit longer term impact on midwifery practice and patient outcomes are recommended

Renal and salt gland function in the Jackass penguin (Speniscus [i.e. Spheniscus] demersus Linn.) with special reference to the renal portal system

Thesis (M. Sc.) -- University of Stellenbosch, 1973.Full text to be digitised and attached to bibliographic record

An anatomical and systematic study of the family Mesosauridae (reptilia : proganosauria) with special reference to its associated fauna and palaeoecological environment in the Whitehill Sea

Thesis (Ph.D.) -- University of Stellenbosch, [1981?].ENGLISH ABSTRACT: The anatomy and taxonomy of the southern African fossil reptile Mesosaurus from the Whitehill Shale has shown that the Formation is a chronostratigraphic unit. It is postulated that the almost identical Whitehill and Iraty Formations were deposited in shallow contemporaneous embayments of a central sea arm that occupied a position between the two continents. The water body was stratefied with anoxic, toxic, bottom brines that prevented the establishment of a benthonic fauna. A Study of the newly collected fossil material led to a new interpretation of the cranial morphology of Mesosaurus and it was found to be anapsid and closely allied to Limnoscelis. If M.tenuidens is to be regarded as typical for the Mesosauridae, all the members of the order Proganosauria will have to be transferred to the order Cotylosauria. M. tenuids was found to differ from M.brasiliensis and is the only species of Mesosaurus in the southern African Permo-Carboniferous Whitehill Formation. Along with it two more forms, noteosaurus africanus Broom and a yet unidentified species, identical with or closely allied to Stereosternum tumidum occur

Characterization of dog repellent factor from cuticular secretion of female yellow dog tick, Haemaphysalis leachi

During its natural life cycle, the yellow dog tick, Haemaphysalis leachi, has three hosts, and it has to spend enough time on each of them to complete a blood meal. When irritated, the females of this tick species produce a cuticular secretion that contains a dog-repelling allomone. This improves the tick's chances of survival by deterring the dog from biting the tick off its body. Employing response-guided isolation techniques in conjunction with gas chromatography-mass spectrometry, the defensive allomone of H. leachi was found to consist of the six homologous aliphatic aldehydes from hexanal to undecanal. A mixture of synthetic versions of these six aldehydes in quantities corresponding to those secreted by one tick elicited strong aversion reactions in the majority of dogs of various breeds. © 2006 Springer Science + Business Media, Inc.Articl