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Ultrasonic transducer (UT) systems are used for non-destructive testing and evaluation across a wide range of industries. In the nuclear industry, radiation damage of the UTs can lead to performance degradation or even complete failure. We have investigated the radiation resilience of a new piezo-polymer (PVDF) UT design. The irradiations were performed in a Cobalt-60 gamma facility with total ionising doses up to 10.5 MGy. Continuous pulse-echo measurements were taken in-situ allowing the performance as a function of time to be monitored. In addition to the UT irradiations and measurements, high fidelity Monte Carlo particle transport simulations were performed to study the radiation environments and the ionising dose profiles within the devices under test. These dose profiles were used to gain insight into the behaviour of PVDF under irradiation. Results show that all sensors were able to withstand the doses achieved without suffering complete failure, with the best performing device only losing 47% of its initial amplitude. Dose profiles for the PVDF show piezoelectric performance to increase by up to 7% at doses around 500 kGy after which performance was found to drop linearly at a rate of between 6.5% and 10% per MGy. [ABSTRACT FROM AUTHOR]

Tin Sulphide (SnS) thin films have been deposited on glass slides by thermal evaporation using SnS powder. The improvements in the electrical and photovoltaic properties of SnS thin films annealed at different temperatures (200°C, 300°C, and 400°C) in vacuum for one hour are presented in this work. The photoconductivity response was improved with annealing SnS thin films in vacuum. Better photoconductivity response around the band gap was observed for annealed samples. By hot probe conductivity type was found p-type. [ABSTRACT FROM AUTHOR]

The annealing temperature dependencies of microstructural properties of complex sulfosalts (SnS)x–(Bi2S3)1−x gradient films have been studied. Films were prepared by thermal evaporation with a combinatorial approach on glass substrates. This work aims to investigate the high throughput screening of these sulfosalts as new photovoltaic materials and also to search Cd free photovoltaic materials. The microstructural behaviour and changing of nanocrystalline (SnS)x–(Bi2S3)1−x structures with respect to composition and annealing temperature (200–400 °C) in vacuum was studied. Structural properties were investigated using x-ray diffraction, energy-dispersive x-ray spectroscopy and Raman spectroscopy measurements. At lower annealing temperature only binary phases such as SnS, Bi2S3, SnS2 and Sn2S3 exist while at higher temperature a ternary phase SnBi2S4 was also developed. These crystalline structures originated in orthorhombic and hexagonal phases and depend on annealing temperatures and composition. The phase formation was different at SnS and Bi2S3 rich ends of thin films. Also, crystallite size, dislocation densities and microstrain gradually varied at both ends. Considering the structural point of view, annealing temperature played a key role on enhancement of crystal quality and phase growth in structures from binary to ternary. Raman microscopy showed that films had bands for different phases. In this work we achieved binary, to a combination of binary and ternary phase conversion of (SnS)x–(Bi2S3)1−x system. [ABSTRACT FROM AUTHOR]

The effect of temporal variation in growth rate on per-recruit model outputs was investigated by comparing biological reference points obtained using growth curves derived for Umbrina robinsoni populations from False Bay, on the south coast of South Africa, sampled 10 years apart (1991-1993 and 2001-2003), and applying the two different age-length keys to length frequency data collected over the period 1991-1993 (n = 1 389) for the estimation of total mortality (Z), fishing mortality (F) and spawner biomass per recruit (SB/R). The SB/R and yield per-recruit (Y/R) curves constructed using biological data collected during the two different time periods were very similar, with target and threshold reference points differing only moderately (11%). This suggests that for long-lived species, the frequency of age and growth studies can be at least the lifespan of a cohort if they are to be assessed with a per-recruit approach. The use of the more recent length-at-age data, however, resulted in lower estimates of F (0.61 y-1 vs 1.05 y-1) and a slightly higher spawner biomass per-recruit ratio (19.5% vs 14.5%) for the earlier period. The reduced estimate of F when using the more recent dataset was likely due to a bias towards older fish caused by small sample size, the philopatric nature of U. robinsoni, and possible recruitment collapse. This highlights the importance of having a large, representative sample of length-at-age data for construction of age-length keys. [ABSTRACT FROM AUTHOR]

Slender baardman Umbrina robinsoni are an important component of recreational shore-angler and spearfisher catches along the eastern seaboard of South Africa. Stocks of U. robinsoni at three sites-False Bay, Stil Bay and the KwaZulu-Natal (KZN) coast-were modelled using a per-recruit approach. Total (Z) and fishing (F) mortality rates were estimated by catch-curve analyses using measures of individual size (length or weight) recorded by researchers, divers (log books) or during spearfishing competitions. Based on estimates of F during the period 2001-2003, spawner biomass per-recruit ratios were estimated to be either at or below the 25% threshold (False Bay SB/R = 21% SB/RF = 0, Stil Bay SB/R = 25% SB/RF = 0, and KZN SB/R = 21% SB/RF = 0), suggesting that rates of F were too high. Reductions in F necessary to achieve target fishing mortality levels (FF = 0) at the current minimum size limit (l 40 cm total length) were 51% for Stil Bay and the KZN coast and 57% for False Bay. Based on the bag frequencies from 927 diver outings in KZN (1989-2003), a reduction in bag limit from the current five to two fish is predicted to reduce F in this region by approximately 25%. Increasing the l to 50 cm is predicted to increase SB/R ratios to 36% SB/RF = 0 in False Bay, 43% SB/RF = 0 in KZN and 52% SB/RF = 0 in Stil Bay, at current levels of F. Owing to the philopatric nature of U. robinsoni and the consequent existence of temporary refugia, catch curves are likely to underestimate fishing mortality. The reductions in F estimated to attain the target reference points are therefore probably conservative. [ABSTRACT FROM AUTHOR]

Biological data for Umbrina robinsoni were obtained from fish sampled monthly during 2001-2002 by shore-angling in the warm-temperate De Hoop Marine Protected Area (MPA) (n = 312), and by means of spearfishing during three trips (May, September and January 2001-2002) in the Kosi Bay region of the subtropical Maputaland MPA (n = 354). Annuli in otolith sections were validated by means of marginal increment analyses and fluorochrome marking (oxytetracycline). Maximum ages recorded were 12 and 16 years at Kosi Bay and De Hoop respectively. Kosi Bay fish obtained a significantly greater asymptotic length than De Hoop fish and mean length-at-age (for ages 2-10 years) was significantly greater. The fitted von Bertalanffy growth equations for combined sexes were: Lt = 594 (1 - e-0.183 (t + 2.42)) for De Hoop and Lt = 875 (1 - e-0.151 (t + 2.49)) for Kosi Bay. Trends in mean monthly gonadosomatic indices and proportions of histologically validated macroscopic gonad stages indicated a summer spawning season (November-February) at De Hoop and year-round spawning at Kosi Bay. Relative condition peaked in both spring and autumn at De Hoop but showed little seasonal variation in the Kosi Bay region. Kosi Bay females attained 50% sexual maturity at a significantly larger size (48 vs 39 cm) but at younger age (2.8 vs 3.4 years) than those at De Hoop. Analysis of maturity schedules indicates that current sizes at maturity are plastic responses that maximise lifetime fecundity within local regimes of somatic growth and natural mortality. The instantaneous rate of natural mortality was substantially higher at Kosi Bay than at De Hoop (M = 0.35 vs M = 0.26). [ABSTRACT FROM AUTHOR]

Fish populations in the Berg Estuary on the west coast of South Africa (32°46'S, 18°09'E) were sampled intensively over a four-year period, 2003-2006, in conjunction with a range of physico-chemical variables as part of the Berg River Baseline Monitoring Programme. A considerable body of historic data also exists for the system, dating back a further 10 years, making the Berg Estuary one of the most intensively sampled estuaries in South Africa. Using these data, this paper presents a detailed analysis of the variations in abundance, community structure and size composition of the fish fauna of the Berg Estuary in relation to intra- and inter-annual changes in freshwater flow and other physico-chemical parameters. It also serves to highlight the importance of the Berg Estuary as a nursery area and feeding ground for fish on the South African west coast and provides some insights into the likely impacts the Berg River dam (recently installed in the upper Berg catchment) on the fish fauna of the estuary. It should be noted that the Berg Estuary is one of the longest and largest in SouthAfrica (length=65 km, area=61 km²), and is rated as one of the most important systems in the country from a conservation perspective. Data analysed for the study includes results of ninepling excursions undertaken between 1992 and 2006 during which 42-46 sites were sampled with a 30 m long beach seine net and in some cases with a fleet of gill nets with mesh sizes from 44-145 mm stretched mesh. Total number of fish collected in the seine net hauls per sampling excursion ranged from 20 402-243 226 and biomass from 80-490 kg. Number of species present in the catches ranged from 14-23 species. Fewer species and lower biomass was generally recorded in samples taken during the winter and autumn (high-flow period) relative to summer and spring (low-flow) months. Overall fish abundance (measured as number of individuals per square meter) increased over the study period with an initial modest increase from 2004 onwards followed by a more marked increased from winter 2005 onwards. Species richness (measured as number of species recorded) also exhibited a modest increase over the entire study period, from around 14-18 species between 1992 and 2003, rising to between 17 and 23 species from 2004 onwards. Grouping fish species in accordance with their degree of association with estuaries revealed that marine migrant species accounted for most of the observed variation in abundance and biomass, with estuarine resident species following a more stable trajectory over time. The relative contribution by different groups of fish exhibited no clearly discernible pattern from year to year in relation to measured physico-chemical parameters including freshwater runoff to the estuary, or between seasons. In terms of species composition, Liza richardsonii was the most abundant species overall (average contribution = 59%), followed by Gilchristella aestuaria (22%), Atherina breviceps (8%), Psammogobius knysnaensis (3%), Caffrogobius nudiceps (2%) and Oreochromis mossambicus (2%). Together these six species accounted for 93-99% of the catches in each year (overall average: 97%). Increases in the abundance of L. richardsonii accounted for the major portion of the increase in fish abundance over time, and is thought to be related to the closure of a historic gill net fishery on the estuary in 2003, the primary target for this fishery. Some (but not all) fish species in the estuary displayed clear and consistent distribution patterns up the length of the estuary with freshwater species typically being most abundant in the upper reaches of the estuary and estuarine resident and marine migrant species being more abundant lower down.… [ABSTRACT FROM AUTHOR]

A total of 248 roving creel surveys along the length of the Berg River Estuary, in the Western Cape, South Africa, recorded 626 shore-angler and 88 boat-angler outings over the period December 2002-November 2005. Catch-and-effort information was obtained from catch inspections with 360 handline and 246 rod-anglers. Average total annual linefishing effort was estimated at 449±29 (mean±SE) boat-angler days, 1 299±118 recreational shore-angler days and 1 394±57 subsistence (handline) shore-angler days. The estimated total shore-based linefish catch (excluding boat-based catches) from the estuary for the years 2004 and 2005 was 37 231±1 326 fish and 26 938±706 fish (approximately 8 t and 7 t) respectively. Compared with other estuaries along the South African east coast where angler catches have been surveyed, species diversity in catches from the cool-temperate Berg River Estuary was low, with only 15 species caught, of which three, elf Pomatomus saltatrix (56%), harder Liza richardsonii (31%) and carp Cyprinius carpio (11%), dominated the catch. Average linefish catch per unit effort of most species increased significantly in the two years subsequent to the closure of the long-existing commercial gillnet fishery in March 2003. Length frequency distributions revealed significant increases in the average size and an increased contribution of larger size class elf and harder to the linefish catch over the monitoring period, suggesting a degree of recovery of the estuarine icthyofauna after more than a century of intensive gillnet fishing. [ABSTRACT FROM AUTHOR]

• Canada's AEFI surveillance detected 56 TTS reports following ChAdOx1-S [recombinant]. • There were no TTS reports following Ad26.COV2.S. • Median age: 56 years; 66 % had functionally positive anti-PF4 antibodies; 9 % fatal. • Observed TTS reports exceeded the expected number, estimated from background rates. • National surveillance data informed vaccine program recommendations in Canada. Identifying and monitoring adverse events following vaccination contributed to the safety and effectiveness of COVID-19 mass vaccination campaigns. In March 2021, international reports emerged of an adverse event following vaccination with adenovirus vector COVID-19 vaccines (ChAdOx1-S [recombinant] and Ad26.COV2.S) of thrombosis with low platelet counts, referred to as thrombosis with thrombocytopenia syndrome (TTS). We described TTS reports in Canada following adenovirus vector COVID-19 vaccines and investigated whether the observed number of events were higher than expected. Reports of TTS following receipt of ChAdOx1-S [recombinant] or Ad26.COV2.S meeting the Canadian case definition for TTS and diagnostic certainty levels 1–3 of the Brighton Collaboration case definition, submitted to the Canadian Adverse Events Following Immunization Surveillance System and Canada Vigilance Database between February 26, 2021 and October 31, 2022 were included. Demographics and characteristics of the TTS reports are described along with an analysis comparing the observed number of reports to the expected number. As of October 31, 2022, 56 reports of TTS following administration of ChAdOx1-S [recombinant] and no reports following Ad26.COV2.S vaccines were reported in Canada, of which 37 had functionally positive anti-PF4 antibodies. The median age was 56 years; males accounted for 54 % of reports. Five deaths were reported. The observed number of reports exceeded the expected for all ages and sexes combined, as well as for males aged 30–49 and 60–69 years, and females aged 40–59 years. Based on international surveillance data, Canada evaluated a statistical signal of TTS following adenovirus vector vaccines. The investigation of this signal demonstrated how post-market vaccine safety surveillance systems were successful in investigating rare adverse events during the rollout of COVID-19 vaccines in Canada. As adenovirus vector vaccines continue to be administered, characterization of the association between the vaccine and TTS informs immunization programs and policies. [ABSTRACT FROM AUTHOR]

A rapid screening methodology for the development of transparent conducting oxides is presented. The methodology, based on a combination of spectrophotometry, ellipsometry and 4-point probe measurements, was used to map out the opto-electronic properties over a co-sputtered ZnO : Al2O3 film deposited from separate ceramic targets of ZnO and Al2O3. Clear distributions for the carrier density, ne, and mobility, μe, are determined as a function of wt%. Al2O3 content within the film. A minimum resistivity value of 7.6 × 10−4 Ω cm was achieved for a composition of 1.5 wt%. Al2O3. [ABSTRACT FROM AUTHOR]

Introduction : Le cancer est la principale cause de décès lié à la maladie chez les enfants de 1 à 14 ans au Canada. Malgré l'importance pour la santé publique du cancer chez les enfants, peu de rapports évalués par des pairs ont été publiés sur l'évolution de la situation au Canada. La présente étude porte sur l'évolution des cas de cancer par âge, par sexe et par province de résidence, selon les plus récentes données sur les cancers enregistrés. Méthodologie : Nous avons utilisé les données fondées sur la population du Registre canadien du cancer pour dégager les tendances de l'incidence des cancers primitifs diagnostiqués entre 1992 et 2006 chez les enfants (0-14 ans) pour les 12 grandes catégories de cancer de la Classification internationale du cancer chez les enfants, 3e édition (CICE-3). Résultats : De 1992 à 2006, le taux d'incidence de tous les cancers confondus est demeuré stable, mais les tendances variaient selon le type de cancer. Nous avons observé chez les garçons une diminution significative des rétinoblastomes sur l'ensemble de la période à l'étude (− 6,5 % par année) ainsi qu'une augmentation des leucémies de 1992 à 1999 (+ 3,5 % par année). Chez les filles, nous avons constaté une diminution significative des tumeurs du rein de 1998 à 2006 (− 5,7 % par année) et une augmentation des tumeurs du foie de 1997 à 2006 (+ 8,1 % par année). Nous avons aussi relevé des différences en fonction de l'âge et de la province. Il faut interpréter avec prudence les tendances qui se rapportent à un faible nombre de cas par année ou qui présentent un large intervalle de confiance à 95 %. Conclusions : Les résultats illustrent la nécessité d'une surveillance à l'échelle de la population et des besoins en recherche étiologique. [ABSTRACT FROM AUTHOR]

Abstract: Thin films of Cu3BiS3 have been produced by conversion of stacked and co-electroplated Bi–Cu metal precursors in the presence of elemental sulfur vapor. The roles of sulfurization temperature and heating rate in achieving single-phase good quality layers have been explored. The potential loss of Bi during the treatments has been investigated, and no appreciable compositional difference was found between films sulfurized at 550°C for up to 16h. The structural, morphological and photoelectrochemical properties of the layers were investigated in order to evaluate the potentials of the compound for application in thin film photovoltaics. [Copyright &y& Elsevier]

This study compares the fish assemblages of the permanently open cool-temperate Olifants and warm-temperate Breede estuaries on the west and south coasts of South Africa respectively, and their responses to altered freshwater flows. Both estuaries have experienced a >35% reduction in mean annual runoff (MAR) from a historical reference condition to the present day with a >60% reduction possible under future flow scenarios. With the exception of species that have both marine and estuarine breeding populations, the Olifants Estuary fish assemblage has experienced an overall 20% decrease in abundance from reference (pristine state) to the present day and will gradually decline to 55% of reference with a predicted future 60% reduction in MAR. Consequently, future reductions in flow are likely to result in the Olifants Estuary progressing towards a low biomass, low diversity, marine-dominated system. In contrast, reduced freshwater flows in the Breede Estuary are likely to experience an overall reduction in the abundance of species that breed only in estuaries, and in freshwater and catadromous species. Collectively, entirely estuarine-dependent fish will increase in abundance, but considered individually some important exploited species such as Argyrosomus japonicus and Pomadasys commersonnii will collapse to 50% of historical numbers once there has been a 64% reduction in MAR. Overall, fish abundance in the estuary has increased by 6% from reference to the present day and is likely to increase to 115% of reference with future reductions in flow. Some species with a preference for fresh and brackish water will be all but lost from the system, but overall diversity is likely to increase with the range expansion of warm-temperate and subtropical marine species westward. In all, the fish assemblage of the Breede Estuary will experience a gradual change from a relatively high-diversity, low-abundance, freshwater-rich system under historical flow conditions to a high-diversity, high-abundance, marine-dominated system with future reductions in flow. [ABSTRACT FROM AUTHOR]

The southern mullet Chelon richardsonii (Mugilidae) is the main target species of the inshore net fishery (gillnet and beach-seine) on the west coast of South Africa. The stock has displayed symptoms of overfishing, with a 28% reduction in the standardised catch per unit effort (CPUE) between 2008 and 2016, and a 36.5-mm reduction in mean total length (TL) of fish in the commercial catch between 1998 and 2017. The socioeconomic importance of the inshore net fishery and concern regarding stock status necessitated an assessment of the C. richardsonii stock. This work presents an update of the life-history parameters and the first stock assessment of C. richardsonii at the centre of its distribution—Saldanha Bay and Langebaan Lagoon—using CPUE standardisation and per-recruit analysis. The sexes exhibited distinctive growth, with females growing larger, and their length-at-first-maturity was estimated at 205 mm TL, corresponding to age 2 years. Estimated natural mortality was 0.718 y–1, total mortality was 1.599 y–1, and fishing mortality was 0.881 y–1. Current spawner- biomass-per-recruit was estimated at 24.5% of the pristine (unfished) levels, indicating a stock at risk of recruitment failure. An increase in the minimum stretched mesh size of the gillnets to 51 mm and a reduction in fishing mortality to 0.60 y–1 (approximately 30%) would facilitate the recovery of the spawner biomass to the target of 40% of pristine (SB40). [ABSTRACT FROM AUTHOR]

White stumpnoseRhabdosargus globicepsis the main target of the linefishery in Saldanha Bay. Increased fishing pressure over the last three decades, particularly by the recreational sector, has led to concerns regarding sustainability of the local white stumpnose stock. The fishery was exceptionally productive between 2006 and 2008, with an estimated annual catch of 141.2 tonnes (t). Only 3% of boat outings surveyed were commercial boats targeting white stumpnose, yet this sector accounted for 39.3 t (31%) of the average annual catch. The recreational boat sector accounted for most of the catch (70.0 t), and the recreational shore sector the least (31.9 t). Commercial boat catch per unit effort (CPUE; 3.7 fish angler–1h–1) was more than 10 times that of recreational boats (0.3 fish angler–1h–1). White stumpnose catch length-frequency differed significantly (p< 0.01) between the fishing sectors, with the commercial sector retaining larger fish (34.7 cm [SD 5.9]) than the recreational boat (33.9 cm [SD 5.9]) and shore (30.4 cm [SD 5.8]) sectors. A decline in commercial CPUE (2000–2015) of approximately 40% and a concomitant severe decline (>95%) in survey data for juvenile white stumpnose CPUE (2007–2016) indicate that the current rate of exploitation is not sustainable. Recovery of the white stumpnose stock will require a decrease in fishing mortality. Possible management regulations include sector-specific effort limitations, extending the ‘no take’ marine protected area, reducing the recreational-sector bag limit to 5 fish person–1day–1, implementing a commercial-sector bag limit, and increasing the minimum size limit to 30 cm TL. [ABSTRACT FROM AUTHOR]

Abstract: Ultra-thin photovoltaic (PV) devices were produced by atmospheric pressure metal organic chemical vapour deposition (AP-MOCVD) incorporating a highly absorbing intermediate sulphurised FeSx layer into a CdS/CdTe structure. X-ray diffraction (XRD) confirmed a transitional phase change to pyrite FeS2 after post growth sulphur (S) annealing of the FeSx layer between 400°C and 500°C. Devices using a superstrate configuration incorporating a sulphurised or non-sulphurised FeSx layer were compared to p–n devices with only a CdS/CdTe structure. Devices with sulphurised FeSx layers performed least efficiently, even though pyrite fractions were present. Rutherford back scattering (RBS) confirmed deterioration of the CdS/FeSx interface due to S inter-diffusion during the annealing process. [Copyright &y& Elsevier]

A prospective, cohort survey of 540 mid-adolescent students was conducted to identify personal, family and social correlates of alcohol use. A structured questionnaire recorded alcohol involvement, other substance use, perceived parental alcohol use and related factors, alcohol-related attitudes and beliefs, psychological well-being, social and peer behaviours, and school conduct problems. Participants drank on 17.5 days in the past 3 months; on a typical drinking day they consumed 4.7 units, with 28.5% reported drinking six or more units. More frequent drinking was independently correlated with being male, perceiving that parents encouraged drinking, drinking without parental knowledge, drinking to alter mood, buying alcoholic beverages, spending more time with friends who drink, perceiving social pressure to drink, and being excluded from school and truanting. Parental discouragement for alcohol was related to more frequent drinking in females and less frequent drinking in males. Drinking more intensively was associated with use of cannabis, parental encouragement to drink, spending more time with friends who drink, school exclusion, and being in trouble with teachers. These results highlight multidimensional correlates of drinking during mid-adolescence and underline the importance of addressing personal, family, peer, and school conduct factors in school-based alcohol education programmes. [ABSTRACT FROM AUTHOR]

Making sense of rapidly evolving evidence on genetic associations is crucial to making genuine advances in human genomics and the eventual integration of this information in the practice of medicine and public health. Assessment of the strengths and weaknesses of this evidence, and hence the ability to synthesize it, has been limited by inadequate reporting of results. The STrengthening the REporting of Genetic Association studies (STREGA) initiative builds on the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement and provides additions to 12 of the 22 items on the STROBE checklist. The additions concern population stratification, genotyping errors, modelling haplotype variation, Hardy-Weinberg equilibrium, replication, selection of participants, rationale for choice of genes and variants, treatment effects in studying quantitative traits, statistical methods, relatedness, reporting of descriptive and outcome data, and the volume of data issues that are important to consider in genetic association studies. The STREGA recommendations do not prescribe or dictate how a genetic association study should be designed but seek to enhance the transparency of its reporting, regardless of choices made during design, conduct, or analysis. [ABSTRACT FROM AUTHOR]