Evolutionary impact assessment of the North Sea plaice fishery

There is growing evidence that fishing causes evolution in life-history traits that affect the productivity of fish stocks. Here we explore the impact of fisheries-induced evolu-tion (FIE) on the productivity of North Sea plaice using an eco-genetic individual-based model by comparing management scenarios with and without an evolutionary re-sponse. Under status-quo management, plaice evolve towards smaller size at age, ear-lier maturation, and higher reproductive investment. Current reference points of maximum sustainable yield (MSY) and corresponding fishing-mortality rate ( ) that ignore FIE will decrease and cannot be considered sustainable. The nature and extent of the change through FIE depend on fishing effort and selectivity. The adverse evolutionary effects can be reduced – and even reversed – by implementing a dome-shaped exploitation pattern protecting the large fish. The evolutionarily sustainable maximum yield can be obtained by combining such a dome-shaped exploitation pattern with a reduction in fishing mortality and an increase in mesh size; it is similar to the maximum sustainable yield that would apply if life-history traits were static. Fisheries managers will need to trade off the short-term loss in yield associated with evolutionarily informed management with the long-term loss in yield FIE causes under evolutionarily uninformed management

The analysis of road traffic accident data in the implementation of road safety remedial programmes

Thesis (M.Ing.)--Stellenbosch University, 2001.ENGLISH ABSTRACT: A road safety remedial programme has as an objective the improvement of road transportation safety by applying road safety engineering remedial measures to hazardous road network elements in a manner that will be economically efficient. Since accident data is the primary manifestation of poor safety levels it must be analysed in manner that will support the overall objective of economic efficiency. Three steps in the process of implementing a road safety remedial programme, that rely on the systematic analysis of accident data, are the identification of hazardous locations, the ranking of hazardous locations and the evaluation of remedial measure effectiveness. The efficiency of a road safety remedial programme can be enhanced by using appropriate methodologies to measure safety, identify and rank hazardous locations and to determine the effectiveness of road safety remedial measures. There are a number of methodologies available to perform these tasks, although some perform much better than other. Methodologies based on the Empirical Bayesian approach generally provide better results than the Conventional methods. Bayesian methodologies are not often used in South Africa. To do so would require the additional training of students and engineering professionals as well as more research by tertiary and other research institutions. The efficiency of a road safety remedial programme can be compromised by using poor quality accident data. In South Africa the quality of accident data is generally poor and should more attention be given to the proper management and control of accident data. This thesis will report on, investigate and evaluate Bayesian and Conventional accident data analysis methodologies.AFRIKAANSE OPSOMMING: Die doel van 'n padveiligheidsverbeteringsprogram is om op die mees koste effektiewe manier die veiligheid van onveilige padnetwerkelemente te verbeter deur die toepassing van ingenieursmaatreëls. Aangesien padveiligheid direk verband hou met verkeersongelukke vereis die koste effektiewe implementering van 'n padveiligheidsverbeteringsprogram die doelgerigte en korrekte ontleding van ongeluksdata. Om 'n padveiligheidsverbeteringsprogram te implementeer word die ontleding van ongeluksdata verlang vir die identifisering en priortisering van gevaarkolle, sowel as om die effektiwiteit van verbeteringsmaatreëls te bepaal. Die koste effektiwiteit van 'n padveiligheidsverbeteringsprogram kan verbeter word deur die regte metodes te kies om padveiligheid te meet, gevaarkolle te identifiseer en te prioritiseer en om die effektiwiteit van verbeteringsmaatreëls te bepaal. Daar is verskeie metodes om hierdie ontledings te doen, alhoewel sommige van die metodes beter is as ander. Die 'Bayesian' metodes lewer oor die algemeen beter resultate as die gewone konvensionele metodes. 'Bayesian' metodes word nie. in Suid Afrika toegepas nie. Om dit te doen sal addisionele opleiding van studente en ingenieurs vereis, sowel as addisionele navorsing deur universiteite en ander navorsing instansies. Die gebruik van swak kwaliteit ongeluksdata kan die integriteit van 'n padveiligheidsverbeteringsprogram benadeel. Die kwaliteit van ongeluksdata in Suid Afrika is oor die algemeen swak en behoort meer aandag gegee te word aan die bestuur en kontrole van ongeluksdata. Die doel van hierdie tesis is om verslag te doen oor 'Bayesian' en konvensionele metodes wat gebruik kan word om ongeluksdata te ontleed, dit te ondersoek en te evalueer.Maste

Re-identification of a lamnid shark embryo

nant female lamnid shark was caught that the morphometric arguments in the Strait of Messina, Mediterra- used by Sanzo (1912) did not rule out nean Sea. She was reported to contain the shortfin mako (Isurus oxyrinchus 25–30 embryos, one of which was Rafinesque, 1810) but that the high saved and taken to the local Marine fecundity of 25–30 was more consis-Institute, where it was subsequently tent with C. carcharias than with I. examined by Sanzo (1912). The male oxyrinchus or a Lamna species. A lack embryo measured 36.1 cm total length of information on lamnid reproduction (TL), weighed 800 g, and had a greatly and the misidentification of a likely distended abdomen, as is typical of Galeorhinus galeus (Stevens2) with a embryos of oophagous lamnoid sharks litter of 30 as Lamna by Neill (1811), (Gilmore, 1993). The mother and the may have led Sanzo (1912) to consider remaining embryos were not saved. the porbeagle Lamna nasus (Bon-Because Sanzo was not able to exam- naterre, 1788) instead of the shortfin ine the adult female from which the mako as the most likely alternativ

Diagnostic accuracy of computed tomography coronary angiography in patients with a zero calcium score

To evaluate the diagnostic accuracy of 64-slice CT coronary angiography (CT-CA) for the detection of significant coronary artery stenosis in patients with zero on the Agatston Calcium Score (CACS). We enrolled 279 consecutive patients (96 male, mean age 48±12 years) with suspected coronary artery disease. Patients were symptomatic (n=208) or asymptomatic (n=71), and underwent conventional coronary angiography (CAG). For CT-CA we administered an IV bolus of 100 ml of iodinated contrast material. CT-CA was compared to CAG using a threshold for significant stenosis of ≤50%. The prevalence of disease demonstrated at CAG was 15% (1.4% in asymptomatic). The population at CAG showed no or non-significant disease in 85% (238/279), single vessel disease in 9% (25/279), and multi-vessel disease in 6% (16/279). Sensitivity, specificity, and positive and negative predictive values of CT-CA vs. CAG on the patient level were 100%, 95%, 76%, and 100% in the overall population and 100%, 100%, 100%, and 100% in asymptomatic patients, respectively. CT-CA proves high diagnostic performance in patients with or without symptoms and with zero CACS. The prevalence of significant disease detected by CT-CA was not negligible in asymptomatic patients. The role of CT-CA in asymptomatic patients remains uncertain

A scale-down mimic for mapping the process performance of centrifugation, depth and sterile filtration

In the production of biopharmaceuticals disk-stack centrifugation is widely used as a harvest step for the removal of cells and cellular debris. Depth filters followed by sterile filters are often then employed to remove residual solids remaining in the centrate. Process development of centrifugation is usually conducted at pilot-scale so as to mimic the commercial scale equipment but this method requires large quantities of cell culture and significant levels of effort for successful characterization. A scale-down approach based upon the use of a shear device and a bench-top centrifuge has been extended in this work towards a preparative methodology that successfully predicts the performance of the continuous centrifuge and polishing filters. The use of this methodology allows the effects of cell culture conditions and large-scale centrifugal process parameters on subsequent filtration performance to be assessed at an early stage of process development where material availability is limited

Contamination de l’environnement et de la faune par des polluants industriels : les diphényles polychlorés (P.C.B.)

Richou-Bac Lucien, Cumont G., Mollet M. F., Pantaléon Jean. Contamination de l’environnement et de la faune par des polluants industriels : les diphenyles polychlorés (P.C.B.). In: Bulletin de l'Académie Vétérinaire de France tome 125 n°6, 1972. pp. 293-303

Evidence for Color Fluctuations in Hadrons from Coherent Nuclear Diffraction}

A QCD-based treatment of projectile size fluctuations is used to compute inelastic diffractive cross sections $\sigma_{diff}$ for coherent hadron-nuclear processes. We find that fluctuations near the average size give the major contribution to the cross section with $\le few \%$ contribution from small size configurations. The computed values of $\sigma_{diff}$ are consistent with the limited available data. The importance of coherent diffraction studies for a wide range of projectiles for high energy Fermilab fixed target experiments is emphasized. The implications of these significant color fluctuations for relativistic heavy ion collisions are discussed.Comment: Report number DOE/ER 40427-13-N93 11 pages, 3 figures available from author Mille

Données récentes sur la contamination des produits laitiers français par les composés organo-chlorés

Richou-Bac Lucien, Mollet M. F., Restuit Annick, Pantaléon Jean. Données récentes sur la contamination des produits laitiers français par les composés organo-chlorés. In: Bulletin de l'Académie Vétérinaire de France tome 127 n°8-9, 1974. pp. 379-390