507 research outputs found
Des ateliers à la ferme: apports et contraintes spécifiques rencontrés par les personnes en situation de handicap en intégration dans des fermes pédagogiques
Notre recherche provient d’entretiens effectués auprès d’intervenants sociaux travaillant dans des fermes pédagogiques de Suisse romande. Elle relève comme principaux apports la valorisation, la confiance en soi ainsi que la responsabilisation qui aident les personnes en situation de handicap à acquérir des compétences professionnelles et les motivent à travailler dans ces structures. L’enquête décèle des contraintes comme les dangers et les risques de blessures liés aux activités. Les professionnels sociaux doivent adapter l’environnement afin de limiter le nombre de tâches irréalisables par les travailleurs. Ces derniers peuvent augmenter leurs capacités physiques et leur motricité. Par contre, des réelles limites d’intégration sont observées pour des personnes à mobilité réduite. Nos objectifs sont de promouvoir des activités de ce genre auprès de nos institutions
Influence of host nutritional condition on post-infection traits in the association between the manipulative acanthocephalan Pomphorhynchus laevis and the amphipod Gammarus pulex.
12 pagesInternational audienceSeveral parasites with complex life-cycles induce phenotypic alterations in their intermediate hosts. According to the host manipulation hypothesis, such phenotypic alterations are supposed to increase the fitness of the parasite at the expense of that of its intermediate hosts through increasing the probability of transmission to next hosts. Although the phenomenon has received a large attention, the proximate factors modulating the occurrence and intensity of host manipulation remain poorly known. It has however, been suggested that the amount of energy reserves in the intermediate host might be a key parameter, although its precise influence on the intensity of manipulation remains unclear. Dietary depletion in the host may also lead to compromise with other parasite traits, such as probability of establishing or growth or virulence. Here, we address the question through performing experimental infections of the freshwater amphipod Gammarus pulex with two different populations of the acanthocephalan fish parasite Pomphorhynchus laevis, and manipulation of host nutritional condition. Following exposure, gammarids were given either a "standard" diet (consisting of elm leaves and chironomid larvae) or a "deprived" food treatment (deprived in proteins), and infection parameters were recorded. Once parasites reached the stage at which they become infective to their definitive host, refuge use (a behavioural trait presumably implied in trophic transmission) was assessed, and metabolic rate was measured. Infected gammarids exposed to the deprived food treatment showed a lower metabolic rate, indicative of a lower body condition, compared to those exposed to the standard food treatment. Parasite size was smaller, and, depending on the population of origin of the parasites, intensity of infection was lower or mortality was higher in deprived hosts. However, food treatment had no effect on either the timing or intensity of behavioural modifications. Overall, while our results suggest that acanthocephalan parasites develop better in hosts in good condition, no evidence was found for an influence of host nutritional condition on host manipulation by parasites
Multi-Atlas based Segmentation of Head and Neck CT Images using Active Contour
This paper presents the segmentation of bilateral parotid glands in the Head and Neck (H&N) CT images using an active contour based atlas registration. We compare segmentation results from three atlas selection strategies: (i) selection of "single-most-similar" atlas for each image to be segmented, (ii) fusion of segmentation results from multiple atlases using STAPLE, and (iii) fusion of segmentation results using majority voting. Among these three approaches, fusion using majority voting provided the best results. Finally, we present a detailed evaluation on a dataset of eight images (provided as a part of H&N auto segmentation challenge conducted in conjunction with MICCAI-2010 conference) using majority voting strategy
Introduction of a urodynamic score to detect pre- and postoperative neurological deficits in children with a primary tethered cord
Object: An increasing number of asymptomatic children are diagnosed with occult spinal dysraphism, raising the question of their optimal management. Urodynamic study (UDS) is the most reliable method of detecting neuro-urological abnormalities in these children. The rate of postoperative retethering ranges from 10 to 20% and is not always immediately clinically significant. The aim of this prospective study was to develop a reliable method that could be used in the preoperative assessment and postoperative follow-up of children with a tethered cord syndrome (TCS). Methods: From 1989 to 1997, 15 children underwent spinal cord untethering for TCS. Preoperatively, patients were assessed with MRI and UDS. Postoperative UDS were repeated at 6- to 12-month intervals. Four UDS parameters were identified, graded, and added to obtain a UDS score. A group of 38 children without dysraphic condition was used as control and allowed the calculation of a normal score. Conclusions: There was a statistically significant difference in the preoperative UDS scores between the control group and the study group (p<0.001). Postoperatively, there was a statistically significant improvement (p<0.001) in UDS scores. UDS score is a reliable tool for identifying and quantifying neuro-urological disorders in patients with TCS. Postoperatively, this score was useful in the early diagnosis of spinal cord retetherin
Evaluation of nanometer thick mercury film electrodes for stripping chronopotentiometry
In this work, the performance and applicability of the thin mercury film electrode (TMFE) in the heavy metal speciation, by stripping chronopotentiometry (SCP), were exploited. The TMFE thickness was optimized and a 7.6 nm mercury film was selected. This TMFE was mechanically stable and able to perform 60 SCP consecutive measurements, with no significant variation in the analytical signal of lead(II) (RSD less than 2%). Due to the small electrode thickness the measurements were performed under conditions of complete depletion over a wide oxidation current (Is) range, i.e., within the interval [75–500] × 10−9 A. The limit of detection (3σ) for lead(II) was 2.4 × 10−9 M for a deposition time of 40 s and an oxidation current of 75 × 10−9 A. The TMFE was successfully applied to the construction of SSCP experimental waves, which were in conformity to those predicted by the theory. The stability constant calculated (K′) for the Pb(II)-carboxylated latex nanospheres system using a TMFE, agreed with the one obtained using the HMDE, for identical experimental conditions
The use of microelectrodes with AGNES
Absence of gradients and nernstian equilibrium stripping (AGNES) is a new electroanalytical technique designed to determine free heavy metal ion concentrations in solutions. AGNES had been applied, up to date, with conventional equipment such as the hanging mercury drop electrode (HMDE). Due to their much smaller volume, microelectrodes can reach a given preconcentration factor within a much shorter deposition time, so their use for AGNES has been evaluated in this work. For the particular case of the mercury microelectrode deposited onto an Ir disk (radius around 5 lm), AGNES has been successfully used for speciation purposes in the system Pb + PDCA (pyridinedicarboxylic acid). However, due to a relatively large capacitive current, which decays slowly, the limit of quantification for such microelectrodes has only been reduced by one half with respect to that of the HMDE
Chemical characteristics of groundwaters at two massive sulphide deposits in an area of previous mining contamination, South Iberian Pyrite Belt, Spain
A detailed chemical study of groundwater was carried out to elucidate the processes controlling the oxidation and dissolution of sulphide minerals at two massive sulphide deposits in the Iberian Pyrite Belt (IPB), i.e. the mined La Zarza deposit and the unmined Masa Valverde deposit. It was found that major-element compositions varied according to the hydrological regime, La Zarza being in a relatively high area with groundwater recharge (and disturbance due to the human factor) and Masa Valverde being in a relatively low area with groundwater discharge. The variations mainly concem pH, Eh, S04 and Na concentrations. Metal concentrations were determined (a) by ICP-MS after filtration, and (b) in sorne cases by voltammetric measurement of Cu, Pb, Zn, Cd and Mn using the Voltammetric In situ Profiling (VIP) System, which allows detection of only the mobile fractions of trace elements (i.e., free metal ions and small labile complexes a few nanometers in size). If one compares the results obtained by each of the two methods, it would appear that the groundwater shows significant enhancement of metal solubility through complexing with organic matter andlor adsorption onto colloids andlor small particles. In areas of sulphide oxidation, however, this solubility enhancement decreases according to Cu> Zn>Cd>Pb. Dnder very low redox conditions, the attained metal concentrations can be several orders of magnitude (up to 108-1 09 for Cu and 102-103 for Pb) larger than those expected from equilibrium with respect to sulphide minerals as calculated with the EQ3NR geochemical code; Zn concentrations, however, are close to equilibrium with respect to sphalerite. The implication of these results is discussed with respect both to mineral exploration and to environmental issues
A treatment planning intercomparison of proton and intensity modulated photon radiotherapy.
peer reviewedAbstract
Purpose: A comparative treatment planning study has been undertaken between standard photon delivery techniques,b intensity modulated photon methods and spot scanned protons in order to investigate the merits and limitations of each of these treatment approaches.
Methods: Plans for each modality were performed using CT scans and planning information for nine patients with varying indications and lesion sites and the results have been analysed using a variety of dose and volume based parameters.
Results: Over all cases, it is predicted that the use of protons could lead to a reduction of the total integral dose by a factor three compared to standard photon techniques and a factor two compared to IM photon plans. In addition, in all but one Organ at Risk (OAR) for one case, protons are predicted to reduce both mean OAR dose and the irradiated volume at the 50% mean target dose level compared to both photon methods. However, when considering the volume of an OAR irradiated to 70% or more of the target dose, little difference could be shown between proton and intensity modulated photon plans. On comparing the magnitude of dose hot spots in OARs resulting from the proton and IM photon plans, more variation was observed, and the ranking of the plans was then found to be case and OAR dependent.
Conclusions: The use of protons has been found to reduce the medium to low dose load (below about 70% of the target dose) to OARs and all non-target tissues compared to both standard and inversely planned photons, but that the use of intensity modulated photons can result in similar levels of high dose conformation to that afforded by protons. However, the introduction of inverse planning methods for protons is necessary before general conclusions on the relative efficacy of photons and protons can be drawn
Integrated Microanalytical System for Simultaneous Voltammetric Measurements of Free Metal Ion Concentrations in Natural Waters
Bacterial communities in trace metal contaminated lake sediments are dominated by endospore-forming bacteria
Lake sediments in areas close to the outlet of wastewater treatment plants are sinks for pollutants. Bacterial communities in sediments are likely affected by the released effluents, but in turn they might modify the distribution and bioavailability of pollutants. On the shore of Lake Geneva, Switzerland, wastewater from the City of Lausanne is treated and discharged into the lake via an outlet pipe in the Vidy Bay. The objectives of this study were to assess (1) the impact of the treated wastewater release on the bacterial communities in the Vidy Bay sediments and (2) the potential link between bacterial communities and trace metal sediment content. Bacterial community composition and abundance were assessed in sediments collected in three areas with different levels of contamination. The main factors affecting bacterial communities were inferred by linking biological data with chemical analyses on these sediments. Near to the outlet pipe, large quantities of bacterial cells were detected in the three upper most cm (3.2 × 109 cells assessed by microscopy and 1.7 × 1010 copies of the 16S rRNA gene assessed by quantitative PCR, per gram of wet sediment), and the dominant bacterial groups were those typically found in activated sludge (e.g. Acidovorax defluivii and Hydrogenophaga caeni). Three samples in an area further away from the outlet and one sample close to it were characterized by 50 % of endospore-forming Firmicutes (Clostridium spp.) and a clear enrichment in trace metal content. These results highlight the potential role of endospore-forming Firmicutes on transport and deposition of trace metals in sediments
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