How the composition of sandstone matrices affects rates of soil formation

Soils deliver multiple ecosystem services and their long-term sustainability is fundamentally controlled by the rates at which they form and erode. Our knowledge and understanding of soil formation is not commensurate with that of soil erosion, in part due to the difficulty of measuring the former. However, developments in cosmogenic radionuclide accumulation models have enabled soil scientists to more accurately constrain the rates at which soils form from bedrock. To date, all three major rock types – igneous, sedimentary and metamorphic lithologies – have been examined in such work. Soil formation rates have been measured and compared between these rock types, but the impact of rock characteristics on soil formation rates, such as rock matrices and mineralogy, have seldom been explored. In this UK-based study, we used cosmogenic radionuclide analysis to investigate whether the lithological variability of sandstone governs pedogenesis. Soil formation rates were measured on two arable hillslopes at Woburn and Hilton, which are underlain by different types of arenite sandstone. Rates were faster at Woburn, and we suggest that this is due to the fact that the Woburn sandstone formation is less cemented that that at Hilton. Similarly, rates at Woburn and Hilton were found to be faster than those measured at two other sandstone-based sites in the UK, and faster than those compiled in a global inventory of cosmogenic studies on sandstone-based soils. We suggest that the cementing agents present in matrix-abundant wackes studied previously may afford these sandstones greater structural integrity and resistance to weathering. This work points to the importance of factoring bedrock matrices into our understanding of soil formation rates, and the biogeochemical cycles these underpi

Imagerie tomodensitométrique thoracique après exposition à l’amiante

International audienceThe complementary examination recommended in France for the follow-up of populations previously exposed to asbestos is the thoracic computed tomography (CT) examination, without injection of contrast product, with millimetric sections. The most frequently observed abnormalities related to this exposure are localized fibrosis of the parietal pleura (or pleural plaques), a benign condition with no therapeutic issue but involving significant medico-social issues in France (in particular recognition as an occupational disease, compensation by the Fund compensation for asbestos victims). In a French study, involving more than 5,000 subjects previously exposed to asbestos, discrepancies in interpretation were reported according to the expertise of the doctor in charge of interpreting the CT scan (substantial percentage of false positives, and even higher frequency of false negatives for pleural plaques when comparing the interpretation of the radiologist who performed the examination and that of a radiologist expert in thoracic imaging). Given the medico-social issues and from a perspective of social equity, it seems important to be very rigorous in the technical methods of carrying out and interpreting the chest CT examinations performed in the follow-up assessments after exposure to asbestos, in particular with a view to medico-social requests. It is recommended that the occupational physician involved in asbestos post-exposure follow-up, and also the physician in charge of examining a case for compensation, request a re-reading by an expert physician based on the tools offered by the Haute Autorité de santé and updated in 2019.L’examen complémentaire recommandé en France pour le suivi des populations antérieurement exposées à l’amiante est l’examen tomodensitométrique (TDM) thoracique, sans injection de produit de contraste, avec des coupes millimétriques. Les anomalies les plus fréquemment observées liées à cette exposition sont une fibrose localisée de la plèvre pariétale (ou plaques pleurales), affection bénigne sans enjeu thérapeutique mais comportant des enjeux médico-sociaux importants en France (notamment reconnaissance en maladie professionnelle, indemnisation par le Fonds d’indemnisation des victimes de l’amiante). Il a été rapporté dans une étude française, portant sur plus de 5000 sujets antérieurement exposés à l’amiante, des discordances d’interprétation en fonction de l’expertise du médecin en charge de l’interprétation de l’examen TDM (pourcentage substantiel de faux positifs et pourcentage encore plus élevé de faux négatifs, pour les plaques pleurales). Compte tenu des enjeux médico-sociaux et dans une perspective d’équité sociale, il apparaît important d’être très rigoureux dans les modalités techniques de réalisation et d’interprétation des examens TDM thoraciques réalisés dans les bilans de suivi après exposition à l’amiante, en particulier en vue de demandes médico-sociales. Il est recommandé que le médecin du travail impliqué dans le suivi post-exposition à l’amiante, comme le médecin en charge de l’instruction d’un dossier en vue d’indemnisation, sollicite une relecture par un médecin expert s’appuyant sur les outils proposés par la Haute Autorité de santé et mis à jour en 2019

Rôle des SPST (Services de Prévention et de Santé au Travail) pour la traçabilité des expositions, le SPE (Suivi Post-Exposition) et le SPP (Suivi Post-Professionnel) : cadre juridique, questions à traiter, outils disponibles et recommandations de la Société française de médecine du travail

National audienceThe purpose of these recommendations is to clarify the legal framework, delineate the role of occupational health services and make recommendations on the implementation of the visits prior to post-exposure or post professional survey.L’objectif de ces recommandations est de préciser le cadre juridique, délimiter le rôle des Services de prévention et de santé au travail et effectuer des recommandations sur la mise en œuvre des visites en vue d’un suivi post-exposition ou post-professionnel

Crescimento, desenvolvimento gonadal e composição muscular de matrinxãs (Brycon cephalus) submetidos à restrição alimentar e realimentação durante um ano Growth, gonadal development and composition of white and red muscles of matrinxã, Brycon cephalus submitted to food restriction and refeeding during a year

Neste trabalho, avaliou-se o efeito da restrição de ração alternada com realimentação no crescimento, desenvolvimento gonadal e composição muscular de matrinxãs (Brycon cephalus) adultos, de ambos os sexos, durante um ano (janeiro de 1998 a janeiro de 1999). Foram utilizados 135 peixes, separados em dois grupos: controle, alimentado diariamente até aparente saciação, e experimental, submetido ininterruptamente a ciclos de três dias de alimentação/2 dias de restrição de ração (40% de restrição ao mês). Foram realizadas 7 amostragens, nas quais foram utilizados 8 a 10 peixes por grupo. Após anestesia, os peixes foram pesados e as gônadas foram retiradas para determinação do IGS, sexo e fase do ciclo reprodutivo. Porções dos músculos branco e vermelho foram retiradas para determinação da porcentagem de lipídio total, proteína bruta, matéria seca e umidade. Os resultados mostraram que a estratégia alimentar utilizada não afetou o crescimento, o desenvolvimento gonadal e a composição muscular do matrinxã. A restrição de ração seguida por realimentação parece ter desencadeado mecanismos de ajuste metabólico para melhor utilização do alimento e aporte suficiente de energia para o crescimento, processo de maturação gonadal e composição corporal. É possível estabelecer formas de manejo alimentar mais econômicas para o matrinxã sem que processos fisiológicos importantes sejam afetados.<br>This work determined the effect of food restriction and refeeding on the body weight, gonadal maturation and muscle composition of matrinxã, Brycon cephalus, throughout a year (Jan 1998 to Jan 1999). A total of 135 fish, males and females, were split out into two groups. The control group received ration daily up to apparent satiation and the experimental group was alternately fed for 3 days and starved for 2 days (40% of restriction monthly). Seven samplings were carried out, during the experimental period, and at each sampling, after 18-24 hours starving, 8-10 fish were weighed, anesthetized and sacrificed for collection of gonads (gonadosomatic index (GSI), fish sex and reproductive stages) and white and red muscles (determination crude protein, total lipid, dry matter and moisture). The alternate food restriction and refeeding did not affect body weight, gonadal maturation and centesimal composition of muscles of matrinxã. Total lipid, crude protein, dry matter and moisture values remained unchanged face to the lower ration offer. The data showed that the restriction strategy might have triggered mechanisms of metabolic adjustment to improve the utilization of the feeding and to sustain the body homeostasis. The study suggest it is possible to establish economically advantageous feeding schemes for Brycon cephalus without affecting growth, reproduction and carcass composition

Young families under stress: assessing maternal and child well-being using a mixed methods approach

Supporting parents has been reinforced as central to improving children's lives. Assessment of needs, however, is crucial to the provision of effective support. This paper focuses upon the assessment of well-being of mothers and their children in 162 young families experiencing stress in south-east England and Northern Ireland. A mixed-methods approach to assessment was adopted and the strengths of using face-to-face interviews alongside standardized measures are explored

Avaliação do crescimento e do custo da alimentação do pacu (Piaractus mesopotamicus Holmberg, 1887) submetido a ciclos alternados de restrição alimentar e realimentação Evaluation of the growth and feeding costs of pacu (Piaractus mesopotamicus) submitted to alternate cycles of feeding restriction and refeeding

Avaliaram-se os efeitos da utilização de ciclos alternados de restrição alimentar e realimentação no crescimento do pacu, durante o período de engorda, e a viabilidade desta prática na produção comercial da espécie. Juvenis foram distribuídos em três tanques e submetidos a diferentes manejos alimentares, constituindo os tratamentos: A (alimentado ad libitum), B (restrição alimentar de 4 semanas, realimentado por 9 semanas) e C (6 semanas de restrição alimentar, realimentado por 7 semanas), em um total de 13 semanas por ciclo (4 ciclos experimentais). No final de cada ciclo alimentar, 20 peixes de cada tratamento foram amostrados e os dados biométricos registrados. Os valores obtidos para peso, comprimento total e fator de condição (K) foram submetidos a ANOVA e as médias comparadas pelo teste de Duncan. Os resultados mostraram que o tratamento C é o mais indicado somente para outono/inverno, promovendo maior crescimento, menor custo com ração, baixa conversão alimentar e maior receita líquida parcial. Entretanto, durante as estações mais quentes do ano (primavera/verão) outros programas de alimentação devem ser testados, utilizando-se períodos mais curtos de restrição alimentar. Quando se tratou da produção anual, o tratamento A respondeu melhor em termos de biomassa produzida, apesar do maior gasto com alimentação, visto que, com o aumento da temperatura, o crescimento dos peixes dos demais tratamentos ficou prejudicado.<br>The present study evaluated the effects of alternating food restriction and refeeding cycles on the growth of pacu, during the growout phase and the viability of this practice in the commercial production of the species. Juvenile fish were distributed in 3 tanks and submitted to different feeding strategies: group A (fed ad libitum daily), B (food restricted to 4 weeks and refed for 9 weeks) and C (food restricted to 6 weeks and refed for 7 weeks) totalizing 13 weeks per cycle (4 experimental cycles). At the end of each feeding cycle, 20 fish per treatment were sampled and the biometric data were registered. Values of weight, total length and condition factor (K) were submitted to ANOVA and the averages were compared by Duncan test. The results showed that the treatment C presented better results only in autumn/winter periods, promoting better growth, lower cost ration, lower food conversion and better partial net income. Otherwise, during the warmer periods of the year (spring/summer) other feeding strategies must be tested, utilizing shorter periods of food restriction. Regarding to the annual production, the treatment A showed higher biomass, although higher feeding costs. With the increase in the temperature, the growth of the fish from the other treatments was delayed