Dispersion strenghthening of metals Progress report, Sep. 1965 - Feb. 1966

Apparatus constructed for controlled oxidation of iron-beryllium alloy powder

Dynamiques du stockage en eau souterraine et du régime hydrologique des bassins versants Alpins face aux changements climatiques

Le changement climatique aura un impact particulièrement fort sur le bilan hydrique des régions alpines. L'augmentation de la température entraîne un recul des glaciers, la proportion des précipitations qui tombent en forme de neige diminue, et la fonte des neiges se produit plus tôt dans l'année. Ces changements peuvent entraîner une diminution des débits des cours d’eau en été et en automne et éventuellement des pénuries d'eau régionales. La façon dont le régime hydrologique des bassins versants alpins changent dépend de la quantité d'eau de fonte et de précipitation qui est temporairement stockée sous forme d'eau souterraine. Dans une certaine mesure, le stockage souterrain de l'eau pourrait compenser la diminution du stockage sous forme de neige et de glace. Cependant, on en sait relativement peu à ce jour sur le fonctionnement hydrogéologique des zones alpines. Le projet poursuivait deux objectifs. D'une part, nous avons étudié la relation entre les caractéristiques géologiques des bassins, le stockage des eaux souterraines et l’écoulement de surface dans les conditions actuelles. D'autre part, nous avons étudié comment le changement climatique pourrait affecter la dynamique des eaux souterraines et des cours d'eau, en mettant l'accent sur les périodes d’étiages estivales. En particulier, nous avons cherché à savoir si les bassins versants comportant des réservoirs d'eaux souterraines plus importants vont subir moins de changement de leur régime hydrologique. Les recherches se sont concentrées sur les petits bassins versants des hautes Alpes dont le bilan hydrique est dominé par la neige et pour lesquels on dispose principalement de données pluriannuelles pour les cours d’eau. Les recherches sur l'influence de la géologie ont montré que les débits d’étiages augmentent avec l'augmentation de la surface des sédiments non consolidés et sont également influencés dans une moindre mesure par les roches solides à plus forte perméabilité. De vastes dépôts de roche meuble favorisent probablement l'infiltration. Ils peuvent stocker des quantités importantes d'eau et compenser partiellement les déficits saisonniers. Le stockage saisonnier des eaux souterraines dans de tels formations géologiques a été confirmé par des mesures gravimétriques et isotopiques dans un bassin versant de recherche. Nous avons étudié l'effet du changement climatique sur la dynamique des eaux souterraines et les débits des cours d’eau en couplant les modèles climatiques et les modèles hydro(géo)logiques. Pour un bassin de recherche, un modèle a été utilisé qui simule de manière couplée les processus des eaux souterraines et des eaux de surface. Pour les autres bassins versants, un modèle hydrologique conceptuel a été utilisé. Les simulations ont montré qu'en raison de la fonte des neiges plus précoce, la quantité d'eau souterraine stockée et le les débits des cours d’eaux auront tendance à être plus faibles à la fin de l'été/début de l'automne. Toutefois, la diminution relative du volume des eaux souterraines est bien moindre que pour les débits des cours d’eaux. Dans un avenir lointain, le débit des cours d’eaux minimal se déplacera de l'hiver vers les mois d'été. Toutefois, le débit minimal futur en été/automne reste supérieur au minimum actuel en hiver. En outre, les bassins versants présentant des formations géologiques étendues avec une bonne capacité de stockage de l'eau présentent un débit minimal plus élevé. Cela illustre les effets d'équilibrage des processus liés aux eaux souterraines. Le projet montre que les processus hydrogéologiques jouent un rôle important dans la régulation du bilan hydrique des bassins versants alpins, en particulier dans le contexte du changement climatique. En fonction des conditions géologiques, il est possible d'estimer comment les bassins versants pourraient réagir à une fonte des neiges plus précoce et à des périodes de sécheresse estivales. Les débits d’étiages actuels en hiver fournissent également des informations importantes sur l’importance réservoirs d'eaux souterraines dans un bassin versant et leur capabilité de stocker et libérer de l’eau sur une échelle de temps de plusieurs mois. À ce jour, cependant, il n'existe que quelques sites de surveillance dans la région alpine où la dynamique des réservoirs d'eaux souterraines peut être observée directement, ce qui a entraîné des incertitudes dans le projet actuel. En outre, les données sur les précipitations dans la région alpine présentent également de grandes incertitudes. Compte tenu des grands changements attendus, la base de données pour les zones alpines devrait être améliorée

Monitoring of northern climate exposure

Currently, facility managers are faced with many advanced decisions regarding when and how to inspect, maintain, repair or renew existing facilities in a costeffective manner. The evolution of the deteriorations of road structures in reinforced concrete depends on the exposure of the elements to water in liquid form or vapour and to other aggressive agents such as chloride. Current models of ionic transport neglect the effect of real ionic concentration in contact with concrete structures, it means boundary conditions are considered with simple tendency as uniform concentration during the winter period and model parameters are derived from the fitting method. Therefore, it implies in ineffective prediction models of deterioration, i.e. steel rebar corrosion by chloride presence or carbonation, alkali-granular reaction, acid attacks, etc. Structure are sensitive to their environment and their interaction with it is directly related to the processes of deterioration. The degradation of structures exposed to salt-laden mist is faster in the wetter areas. On the contrary, the deterioration of the structures caused by salt spray in the drier zone is slower. The structures, exposed to splashing (precipitation, wind, splash, etc.), have a slower rate of degradation in the wetter regions. The amount of rain has an indirect effect in the process of deterioration of the structure exposed to salt-laden mist because it changes the contact time of chloride on the surface of the structures. For this purpose, a unique exposure monitoring was developed. This mobile station, named MExStUL, contains an atmospheric sensor and new possibilities of chloride detection contained in splashes, mist and static water near the road improving the real exposure of structure and the boundary conditions. First results highlight the real influence of environmental parameters on structures durability on highways. Salt concentration is not uniform during winter period and water thickness demonstrate important periods of drying

Infiltration of Sulfate to Enhance Sulfate Reduction of Petroleum Hydrocarbons

The lack of sufficient electron acceptors, particularly sulfate, can limit the rate of biodegradation of petroleum hydrocarbons (PHCs). Hence there is a growing interest by remediation practitioners to deliver sulfate to a PHC impacted saturated zone to enhance biodegradation. When shallow contamination is present in a relatively permeable aquifer and site constraints allow, a cost-effective approach is to apply sulfate on the ground surface. In this investigation a pilot-scale experiment was conducted to increase our understanding of the delivery of sulfate using a surface-based method and the resulting impact on a shallow PHC contaminated aquifer. A surficial infiltration pond positioned on the ground surface above a well-characterized residual PHC source zone was used to control sulfate dosing. A high-resolution network near the infiltration pond and downgradient of the source zone was employed to monitor relevant geochemical indicators and PHC concentrations. Compound specific isotope analysis (CSIA) was used to identify biodegradation patterns and to investigate the occurrence of microbial sulfate reduction. Selected metabolites and reverse-transcriptase quantitative polymerase chain reaction analyses of expressed biodegradation genes (as mRNA) were also used to characterize the response of indigenous microorganisms (especially sulfate reducing bacteria) to the added sulfate. Three sulfate application episodes (5000 L each) at various Na 2 SO 4 concentrations were allowed to infiltrate under a constant hydraulic head. Although the applied sulfate solution was impacted by density driven advection, detailed monitoring data indicated that the sulfate-enriched water mixed with up-gradient groundwater as it migrated downward through the residual PHC zone and formed a co-mingled downgradient plume with the dissolved PHC compounds. The enrichment of δ 34 S of sulfate in conjunction with a decrease in sulfate concentration showed the occurrence of sulfate reduction due to the applied sulfate. Increased dissolved inorganic carbon (DIC) concentrations associated with a shift toward more depleted values of δ 13 C of DIC was indicative of an input of isotopically depleted DIC from biodegradation of benzene, toluene and o-xylene (BTX). Despite fluctuations in the BTX concentrations, the CSIA data for BTX showed that these compounds were biodegraded. The biomarker data provided supporting evidence that toluene and o-xylene were undergoing anaerobic biodegradation due to sulfate reduction. This study provides insight into factors controlling surface-based delivery of sulfate to shallow PHC impacted groundwater systems, and the value of isotopic and molecular-biological procedures to augment conventional monitoring tools

Prevention of anxiety and depression in the age group of 75 years and over: a randomised controlled trial testing the feasibility and effectiveness of a generic stepped care programme among elderly community residents at high risk of developing anxiety and depression versus usual care [ISRCTN26474556]

BACKGROUND: In frail elderly, the effects of depression and anxiety are deep encroaching. Indicated prevention studies, aimed at subjects with subthreshold disorder, have shown that well designed interventions are capable of reducing the incidence of depression and anxiety. In this randomised prevention trial for elderly, living in the community and suffering from subthreshold depression and anxiety, a stepped care programme was put together to be tested versus usual (GP) care. METHODS/DESIGN: Design: randomised controlled trial. (See figure 1: organisation chart) together with two other projects, this project is part of a national consortium that investigates the prevention of anxiety and depressive disorders in later life using a stepped care programme. The three projects have their own particular focus. This project is aimed at elderly living in the community. Inclusion: subjects with a high risk for depression and anxiety without clinical evidence of these syndromes. The participants are 75 years of age and over and have subthreshold symptoms of depression and or anxiety: they score above the cut-off point on the self-report Centre for Epidemiologic Studies Depression (CES-D) scale, but the criteria for a major depressive disorder or anxiety disorder (panic disorder, agoraphobia, social phobia, generalized anxiety disorder) according to a validated interview, the Mini International Neuropsychiatric Interview (MINI) are not fulfilled. Outcomes: primary outcome: incidence of a depressive or anxiety disorder over a period of two years (MINI); secondary outcome: a positive influence of the intervention, a stepped care programme, on symptoms of depression and anxiety and on quality of life as assessed with the CES D, the HADS A and the SF36 respectively (i.e. stabilisation or improvement of symptoms) [see table 1]. Measurements: Take place at baseline and at 3, 6, 9, 12, 18 and 24 months. Trained independent evaluators assess depression and anxiety status, the primary end point (6, 12, 18, 24 months) [see table 2]. DISCUSSION: Late-life depression and anxiety are characterised by high prevalence, unfavourable prognosis, reduced quality of life, excess mortality and substantial societal costs. No health service, however well equipped, will be able to effectively treat all elderly with depression and anxiety. Therefore, development of (cost) effective means to prevent these disorders is very important

Assertive community treatment for elderly people with severe mental illness

Background: Adults aged 65 and older with severe mental illnesses are a growing segment of the Dutch population. Some of them have a range of serious problems and are also difficult to engage. While assertive community treatment is a common model for treating difficult to engage severe mental illnesses patients, no special form of it is available for the elderly. A special assertive community treatment team for the elderly is developed in Rotterdam, the Netherlands and tested for its effectiveness.Methods: We will use a randomized controlled trial design to compare the effects of assertive community treatment for the elderly with those of care as usual. Primary outcome measures will be the number of dropouts, the number of patients engaged in care and patient's psychiatric symptoms, somatic symptoms, and social functioning. Secondary outcome measures are the number of unmet needs, the subjective quality of life and patients' satisfaction. Other secondary outcomes include the number of crisis contacts, rates of voluntary and involuntary admission, and length of stay. Inclusion criteria are aged 65 plus, the presence of a mental disorder, a lack of motivation for treatment and at least four suspected problems with functioning (addiction, somatic problems, daily living activities, housing etc.). If patients meet the inclusion criteria, they will be randomly allocated to either assertive community treatment for the elderly or care as usual. Trained assessors will use mainly observational instruments at the following time points: at baseline, after 9 and 18 months.Discussion: This study will help establish whether assertive community treatment for the elderly produces better results than care as usual in elderly people with severe mental illnesses who are difficult to engage. When assertive community treatment for the elderly proves valuable in these respects, it can be tested and implemented more widely, and mechanisms for its effects investigated

Reducing depression in older home care clients: design of a prospective study of a nurse-led interprofessional mental health promotion intervention

Abstract Background Very little research has been conducted in the area of depression among older home care clients using personal support services. These older adults are particularly vulnerable to depression because of decreased cognition, comorbid chronic conditions, functional limitations, lack of social support, and reduced access to health services. To date, research has focused on collaborative, nurse-led depression care programs among older adults in primary care settings. Optimal management of depression among older home care clients is not currently known. The objective of this study is to evaluate the feasibility, acceptability and effectiveness of a 6-month nurse-led, interprofessional mental health promotion intervention aimed at older home care clients with depressive symptoms using personal support services. Methods/Design This one-group pre-test post-test study aims to recruit a total of 250 long-stay (> 60 days) home care clients, 70 years or older, with depressive symptoms who are receiving personal support services through a home care program in Ontario, Canada. The nurse-led intervention is a multi-faceted 6-month program led by a Registered Nurse that involves regular home visits, monthly case conferences, and evidence-based assessment and management of depression using an interprofessional approach. The primary outcome is the change in severity of depressive symptoms from baseline to 6 months using the Centre for Epidemiological Studies in Depression Scale. Secondary outcomes include changes in the prevalence of depressive symptoms and anxiety, health-related quality of life, cognitive function, and the rate and appropriateness of depression treatment from baseline to 12 months. Changes in the costs of use of health services will be assessed from a societal perspective. Descriptive and qualitative data will be collected to examine the feasibility and acceptability of the intervention and identify barriers and facilitators to implementation. Discussion Data collection began in May 2010 and is expected to be completed by July 2012. A collaborative nurse-led strategy may provide a feasible, acceptable and effective means for improving the health of older home care clients by improving the prevention, recognition, and management of depression in this vulnerable population. The challenges involved in designing a practical, transferable and sustainable nurse-led intervention in home care are also discussed. Trial Registration ClinicalTrials.gov: NCT0140792