Stable Oxygen and Carbon Isotopic Compositions of Lates stappersii Otoliths from Lake Tanganyika,East Africa

In this study, we measured growth trends in oxygen and carbon isotopic ratios in whole sagittal otoliths from three adult centropomid fish (Lates stappersii) from each of three sub-basins of Lake Tanganyika, East Africa. Sampling density was 20 to 50 samples per otolith. Both δ¹⁸O and δ¹³C values increase with age. The δ¹⁸O data suggest that otoliths were precipitated near the expected equilibrium with the ambient environment (ca. +3.5‰) and support a migration pattern from surface waters during larval stages to deeper waters (40 to 80 m) for mature fish. Relatively high δ¹⁸O values in the southern sub-basin are consistent with cooler temperatures in the region during seasonal upwelling. The δ13C increase from otolith core to edge is large (up to 4‰) and is interpreted as due to ontogenetic changes in diet and contributions from a decrease in the proportion of respired CO₂ incorporated into otolith carbonate as metabolic rates of the fish dropped with maturity. The data seem to successfully reveal life strategy and migration patterns of L. stappersii, document regional differences in lake conditions, and provide a record of temperature within the water column during which the fish lived. Higher resolution studies and analyses of historical samples could be used to constrain modern and past growth patterns, and to reconstruct past temperature gradients and productivity patterns in the lake.     

STUDIES ON YEAST ESTERASE

An esterase (carboxylic acid hydrolase EC 3 1.1.1.) has been prepared from Saccharomyces cerevisiae. This esterase is active at pH 4.4 and, though it is unstable in solution, it can be maintained in an active form either by lyophilization or by coupling to an affinity gel. At pH 4.4, yeast esterase can hydrolyse between 20 and 40% of the esters commonly present in beer, and it is capable of synthesizing ethyl acetate from ethanol and acetic acid in a simple buffered solution without the provision of a co-factor. Different yeast strains yield different amounts of esterase, and there appears to be a positive correlation between the ability of the yeast to form esterase and the level of esters present in fermentations accomplished by that yeast.     

Implantation of multiple intracochlear electrodes for rehabilitation of total deafness: preliminary report

Many instances of total deafness are due to destruction of the organ of Corti but with partial or complete preservation of the function of the cochlear nerve. In such cases, it is possible to restore some hearing by electrically stimulating the fibers of the cochlear nerve with the help of implanted electrodes. Preoperative testing with electric shocks applied to the round window have aroused sensations of noise in 45 cases of total bilateral deafness with a great variety of etiologies. The only negative results were in two cases of operated acoustic neuromas. Our operation places up to eight intracochlear electrodes, each with a separate fenestration opening into an electrically isolated compartment of the scala tympani. Stimulation of each electrode yields a different sound sensation of a pitch that depends on its location along the cochlea. Electric filters direct different frequency bands to the appropriate electrodes, with the necessary compression of dynamic range. In three experimental cases of unilateral deafness, pitch matches to the normal ear were made. In seven therapeutic operations on adult cases of acquired total bilateral deafness, speech recognition was usually relearned within a month or two. Improvement of voice quality was also dramatic. The intracochlear electrodes have been well tolerated for months, but the method of connection to the external equipment still presents difficulties.     

Chylothorax: report of a case complicating ductus ligation through a median sternotomy, and review

An unusual case of chylothorax is described in a 4-year-old child after repair of a ventricular septal defect and ligation of a patent ductus arteriosus through a median sternotomy. Left chylothorax developed after a latent period of six days and was treated initially with continuous drainage and parenteral supplementation of proteins and lipids. Operative intervention with oversewing of the site of the leak in the anterior mediastinum proved necessary after three weeks. The anatomical variations of the thoracic duct are outlined to explain the occurrence of chylothorax after diverse intrathoracic operations. The physiological effects of a thoracic duct fistula and various aspects of management are reviewed.     

The treatment of pain trigger areas in migraine

In many patients with migraine, several localised areas usually on the scalp or neck can be identified. The local injection of lignocaine one per cent and adrenaline 1/200,000 often leads to considerable relief of the symptoms of migraine including visual phenomena. The common sites of the trigger areas are shown and several uncontrolled case reports of the effect of the treatment are described.     

Endocrine studies during the refeeding of young women with nutritional amenorrhea and infertility

Serial endocrine studies were performed during the refeeding of a group of nine young women who presented with amenorrhea associated with injudicious dieting. No significant psychopathology was disclosed by the Lanyon Psychological Screening Inventory in any of the patients, six of whom were single and three married and infertile. The mean weight before refeeding was 81.6% of the normal for height. The mean initial serum follicle-stimulating hormone concentration was within the limits of normal for young women of reproductive age, but the serum luteinizing hormone (LH) concentration and the vaginal maturation score were low. As weight was regained, the serum LH concentration increased (the pooled r for LH versus percent normal weight = 0.85) and the vaginal maturation score rose (the pooled r for vaginal maturation score versus percent normal weight = 0.93). When a mean weight of 96.6% of normal was reached after a mean of 5.3 (range, 2 to 11) months of refeeding, spontaneous menses occurred. The initial cycle was ovulatory in two instances and anovulatory in five, as determined by basal body temperature patterns, plasma progesterone concentrations, and endometrial biopsies. With continued weight gain, menstruation became regular and the three married patients conceived.     

Application of meta-analysis in plant pathology: a case study examining the impact of fungicides on wheat yield loss from the yellow spot—septoria nodorum blotch disease complex in Western Australia

This work was done to demonstrate the opportunities provided by application of meta-analysis in plant pathology. It was a case study used to determine the effectiveness of foliar fungicides in minimising yield loss from a complex of yellow spot (Pyrenophora tritici-repentis) and septoria nodorum blotch (Stagonospora nodorum, teleomorph: Phaeosphaeria nodorum) (YS-SNB disease complex) on wheat in the northern grain-belt of Western Australia. Forty-seven datasets of experimental results from 14 growing seasons, using 18 varieties sprayed one to three times, predominantly with tebuconazole or propiconazole fungicides, were analysed. Across the datasets, the wheat yield gain from fungicide application was 297 kg ha^?1 with a 95 % confidence interval of 11.6 kg ha^?1. Significant yield gains resulted from single or multiple applications of fungicides. Both propiconazole and tebuconazole, increased yield of wheat affected by the YS–SNB disease complex, with yield gain from propiconazole being greater than that from tebuconazole. Yield response varied significantly among crop growing seasons. Meta-analysis was able to aggregate a large number of experimental results and answer important questions related to the variables that influenced those results; in this case the effectiveness of fungicides in minimising yield loss from the YS-SNB disease complex on wheat. It also identified areas where further research needs to be done. It is concluded that meta-analysis has the potential to contribute to similar analyses in other crop disease systems.     

Plant health and food security,linking science,economics, policy and industry

Protecting plant resources from harmful organisms that can spread internationally is a major challenge for plant protection organisations. Natural scientists and economists have methods that contribute to informing and supporting government decision makers in plant health authorities, who also need to account for stakeholders’ views when developing policy and regulations to mitigate plant pest risks. Increasingly plant protection authorities seek to develop integrated decision making through economists and scientists working within an interdisciplinary framework. In this special section of Food Security we introduce a series of papers presented at an international conference that brought together natural scientists, economists, industry representatives and plant health policy makers to report the state of the art and explore the direction and future research needs for such interdisciplinary working to deliver rational plant protection policy and improved food security for the 21st Century. The collection of papers combine contributions from leading academics and influential policy makers and provides cohesive international perspectives on the use of science and economics, as well as their integration, to progress the development of integrated multi-disciplinary plant health policy making around the world. Using a modified version of the world café method during a conference workshop activity, participants identified greater international co-operation as a key mechanism that would reduce international plant health risks. Specifically, co-operation over analysis among stakeholders and along supply chains were seen as key issues.