Variations saisonnières des formes de phosphores dans une station de traitement des eaux usées par lagunage, sous climat aride de Marrakech (Maroc)

L'objectif de ce travail est d'étudier dans un premier temps la dynamique du phosphore dans un système de traitement d 'eaux usées par lagunage facultatif, en relation avec les compartiments biologiques: phytoplancton, zooplancton et bactéries, dans un deuxième temps, d'évaluer, sous les conditions du climat aride, les performances épuratoires de ce système en ce qui concerne les formes du phosphore. Un intérêt particulier est porté au phénomène du relargage du phosphore par les sédiments. Les résultats montrent qu'il y a une évolution saisonnière et cyclique du phosphore dans les bassins de lagunage, en étroite corrélation avec le phytoplancton et le zooplancton. Le phytoplancton représente la part importante des formes organiques du phosphore particulaire. Les meilleures performances d'élimination du phosphore sont notées au printemps (77% pour les PO4 et 64 % pour le phosphore total). La période la moins performante est la période automne-hiver où les rendements moyens ne dépassent pas 38%. Le phosphore éliminé est stocké dans les sédiments. En période estivale, des phénomènes de relargage du phosphore à partir des sédiments ont été mis en évidence, favorisés par une zonation verticale des eaux à cette période. Des essais aulaboratoire ont montré la grande aptitude des sédiments de la station de lagunage étudiée à relarguer le phosphore, avec intervention de l'activité biologique du sédiment.Assimilation, sedimentation and release are the principal mechanisms controlling the behavior of phosphorus in aquatic ecosystems. There are numerous investigations of the phosphorus cycle in lakes and rivers in relation to the eutrophication process. There are, however, few studies about phosphorus cycling in waste stabilization ponds and most of these have discussed phosphorus removal. The aims of this paper were: 1) to study phosphorus dynamics in relation to the biomass compartment (zooplancton, phytoplancton and bacteria); and 2) to evaluate the phosphorus removal efficiency of the treatment plant under arid climatic conditions. Of particular interest was the remobilization of phosphorus from the pond sediment, both under laboratory conditions and in the field. The experimental installation consisted of two ponds receiving domestic wastewater (mean flow=120.4+5.8 m3.day-1 and specific organic load=56 kgBOD.ha-1. day-1; pond area=0.5 ha and depth=1.5 m). Samples were taken twice monthly from the surface, B1(S) and B2(S), and from the 1.5 m layers, B1(F) and B2(F). Composite (24 h) samples were taken from the inflow and the outflowof the plant to determine the removal efficiencies. In each sample, soluble reactive phosphorus (PO4), total phosphorus (PT) and total soluble phosphorus (PTD) were determined. Particulate phosphorus (PTP) was calculated as (PT-PTD) and soluble organic phosphorus (POD) as (PTD-PO4). Phosphorus release was measured in a plexiglas flask containing sediment (collected by corer from the pond bottom) overlaid with distilled water. Over 15 days, daily measurements were made of PO4 and total phosphorus. Sediment dry weight (%), volatile matter, organic carbon (%) and total phosphorus were measured before and after each test. Phosphorus contents of the phytoplankton, zooplankton and bacteria were estimated using the methods of BOUGIS (1974).The results show that cyclical and seasonal variations of phosphorus content were closely correlated with variations in the biological components. Significant correlation coefficients were noted between chlorophyll-a and particulate organic phosphorus. Organic phosphorus in algal cells was the more important form of particulate organic phosphorus. Under the arid climate, the waste stabilization ponds were more efficient at phosphate removal during the spring-summer period (77% of PO4 and 64% of total phosphorus in spring). The first pond may play the major role in phosphate removal. Phosphorus is only eliminated from stabilization ponds through accumulation in the sediment. However, part of the phosphorus which accumulates in pond sediments remains potentially mobile. During the summer period, phosphorus release from the sediment, observed in situ, was favored by stratification of the overlying water. The same phenomenon was noted during the autumn, particularly the release of POD. Laboratory studies have shown that phosphorus release may amount to 55 mg P m-2d-1. Biological activity may play a significant role in this mobilization

Social Functioning and Self-Esteem in Young People with Disabilities Participating in Adapted Competitive Sport

Aims: The aim of this study was to investigate social functioning quality of life and self-esteem in young people with disabilities taking part in adapted competitive sport.Method: A sample of 496 athletes (mean age 16 years 4 months, range: 9 years to 20 years 9 months) was obtained from the 540 participants (91.8%) involved in a French national championship. The main outcome measurements were a social functioning inventory (PedsQL 4.0 social functioning) and a self-esteem inventory in physical areas (physical self inventory 6 PSI-6). Results: The mean PedsQL SF score was 74.6 (SD: 17.7). Comparisons of PedsQL SF according to gender, age, self mobility and training revealed no significant differences between the groups. PedsQL SF was weakly but significantly correlated with all subscales of the PSI-6 in the total population. PSI-6 scores were significantly different between boys and girls, with better self-esteem for boys on general self-esteem (7.7 vs. 6.9, p=0.018), physical condition (6.8 vs. 6.0, p=0.023) and attractive body subscores (6.5 vs. 5.1, p<0.001). Conclusion: Social functioning scores were significantly higher in this population than in the samples of young people with disabilities available in the literature. Interactions between self-concept, social functioning quality of life and participation in adapted sport activities require further studies

Interest of the Ergo-Kit(®) for the clinical practice of the occupational physician. A study of 149 patients recruited in a rehabilitation program

OBJECTIVE: Functional capacity evaluation is commonly used to assess the abilities of patients to perform some tasks. Ergo-Kit(®) is a validated tool assessing both functional capacities of patients and workplace demands. The objective of this study was to evaluate the relevance of the Ergo-Kit(®) data for occupational physicians during the return-to-work process. METHODS: A retrospective and monocenter study was conducted on all patients included in a rehabilitation program and assessed with the Ergo-Kit(®) tool between 2005 and 2014. Workplace demands and patients\u27 functional capacities were evaluated and confronted. Self-beliefs and perceived disability were also assessed and compared to the functional capacity evaluation. RESULTS: One hundred and forty-nine working-age patients (85 men, 64 women; 39±12 years) suffering from musculoskeletal disorders or other diseases were included. Main causes of mismatch between workplace demands and functional capacities were manual handling of loads, postures with arms away from the body and repetitive motions at work; sitting posture was correlated with a lesser physical workload; and Oswestry score was correlated with functional capacities evaluated by the Ergo-Kit(®). CONCLUSION: Ergo-Kit(®) is a relevant tool to assess the multidimensional aspects of workplace demands and functional capacities. It could be very helpful for occupational physicians to manage return-to-work

Effectiveness of three treatment strategies on occupational limitations and quality of life for patients with non-specific chronic low back pain: Is a multidisciplinary approach the key feature to success: study protocol for a randomized controlled trial

BACKGROUND: Chronic low back pain (cLBP) is a significant public health problem, being the primary cause of work absenteeism, as well as affecting sufferers\u27 quality of life, in industrialized society. International guidelines recommend intensive multidisciplinary approaches for patients with cLBP. However, these costly and time-consuming programs can only be offered to a minority of the most heavily affected patients and therefore do not seem likely to respond to public health requirements. Lighter programs may be an alternative to full time hospital-based programs with valuable results in terms of disability and occupational activity for cLBP patients. It is therefore important to define both what the determining components of management to improve activity restriction are and how to treat a larger number of patients more effectively at a lower cost. The aim of this study is to compare three programs with various levels of intensity and multidisciplinary. METHODS/DESIGN: This paper describes the protocol for a prospective, randomized, controlled, clinical trial in working aged patients with cLBP. Three treatment strategies are compared: (1) intensive and multidisciplinary program conducted in a rehabilitation center; (2) less intensive outpatient program conducted by a private physiotherapist; (3) mixed strategy combining the same out program with a multidisciplinary intervention. The primary outcome of the trial is the impact of the mixed strategy on being able to work compared to hospital centered-program and out program. The secondary outcome is the impact of the mixed strategy on quality of life and social ability compared to the two others programs. The intervention part of the trial programs will take 5 weeks and observational follow-up will take 12 months. The sample size will be 180 participants (60 for each arm). The project has been approved by the Ethical Committee of Angers Hospital, France. DISCUSSION: On the hypothesis that a multidisciplinary approach is the key feature to programs success in reducing social and occupational impairment in cLBP patients, we suggest that it is possible to achieve the same results with less intensive strategies if a multidisciplinary approach is maintained. TRIAL REGISTRATION: Current Controlled Trials NCT02030171

Return to work of 87 severely impaired low back pain patients two years after a program of intensive functional restoration

Return to work is the main long-term objective of rehabilitation programs for patients with chronic low back pain (LBP).Objectives Evaluation of work status and number of sick leaves in 87 severely impaired LBP patients 2 years after a functional restoration program. Patients and methods Open prospective study. Population: 87 chronic LBP patients. Intervention: multidisciplinary functional restoration program. Ergonomic advice on the workplace was performed for 53 patients. Outcome: work status and number of sick leaves due to LBP. Results The characteristics of the 26 patients lost to follow-up did not differ significantly from the rest of the population before the program. In the 61 remaining patients, 48 (78%) were at work at 2 years, 43 full-time and 22 at the same job. Nineteen worked in a different environment. Sick leaves were reduced by 60% compared to the 2 years prior to the program: 128 days (± 200 days) versus 329 days (± 179 days); p < 0.005. Conclusion Sick leaves remained significantly reduced and the number of workers who were at work significantly increased at 2 years after an intensive program

Table ronde sur la place de la chirurgie dans les douleurs chroniques du membre supérieur

RésuméLa douleur chronique est d’origine plurifactorielle, elle réalise une véritable maladie à la fois neuromusculaire et psychosociale. Elle met en jeu l’individu dans sa globalité. Il ne faut pas limiter la consultation à une approche uniquement physique et ne pas s’abriter derrière des examens complémentaires inutiles. Il faut savoir écouter le patient, rechercher des éléments de catastrophisme, une hypervigilance, une stratégie d’évitement et évaluer le contexte socioprofessionnel. Le rôle des facteurs psychosociaux est déterminant dans le processus de chronicisation de la douleur et quant aux possibilités de réinsertion professionnelle. La place de la chirurgie peut se résumer au traitement d’une épine irritative (facteur déclenchant) sous réserve qu’elle soit toujours active et que sa suppression permette la régression de l’ensemble du tableau. Mais, le plus souvent, les signes sont mal limités avec une hypersensibilisation plus ou moins diffuse et un dysfonctionnement secondaire de l’ensemble du membre supérieur, une exclusion fonctionnelle et des éléments de déconditionnement sont présents et le contexte psychosocial est défavorable. La prise en charge ne peut alors être que pluridisciplinaire et réalisée au mieux en centre de réadaptation

Multidisciplinary intensive functional restoration versus outpatient active physiotherapy in chronic low back pain: a randomized controlled trial.

STUDY DESIGN: Randomized parallel group comparative trial with a 1-year follow-up period. OBJECTIVE: To compare in a population of patients with chronic low back pain, the effectiveness of a functional restoration program (FRP), including intensive physical training and a multidisciplinary approach, with an outpatient active physiotherapy program at 1-year follow-up. SUMMARY OF BACKGROUND DATA: Controlled studies conducted in the United States and in Northern Europe showed a benefit of FRPs, especially on return to work. Randomized studies have compared these programs with standard care. A previously reported study presented the effectiveness at 6 months of both functional restoration and active physiotherapy, with a significantly greater reduction of sick-leave days for functional restoration. METHODS: A total of 132 patients with low back pain were randomized to either FRP (68 patients) or active individual therapy (64 patients). One patient did not complete the FRP; 19 patients were lost to follow-up (4 in the FRP group and 15 in the active individual treatment group). The number of sick-leave days in 2 years before the program was similar in both groups (180 ± 135.1 days in active individual treatment vs. 185 ± 149.8 days in FRP, P = 0.847). RESULTS: In both groups, at 1-year follow-up, intensity of pain, flexibility, trunk muscle endurance, Dallas daily activities and work and leisure scores, and number of sick-leave days were significantly improved compared with baseline. The number of sick-leave days was significantly lower in the FRP group. CONCLUSION: Both programs are efficient in reducing disability and sick-leave days. The FRP is significantly more effective in reducing sick-leave days. Further analysis is required to determine if this overweighs the difference in costs of both programs

Microfluidic device for robust generation of two-component liquid-in-air slugs with individually controlled composition

Using liquid slugs as microreactors and microvessels enable precise control over the conditions of their contents on short-time scales for a wide variety of applications. Particularly for screening applications, there is a need for control of slug parameters such as size and composition. We describe a new microfluidic approach for creating slugs in air, each comprising a size and composition that can be selected individually for each slug. Two-component slugs are formed by first metering the desired volume of each reagent, merging the two volumes into an end-to-end slug, and propelling the slug to induce mixing. Volume control is achieved by a novel mechanism: two closed chambers on the chip are initially filled with air, and a valve in each is briefly opened to admit one of the reagents. The pressure of each reagent can be individually selected and determines the amount of air compression, and thus the amount of liquid that is admitted into each chamber. We describe the theory of operation, characterize the slug generation chip, and demonstrate the creation of slugs of different compositions. The use of microvalves in this approach enables robust operation with different liquids, and also enables one to work with extremely small samples, even down to a few slug volumes. The latter is important for applications involving precious reagents such as optimizing the reaction conditions for radiolabeling biological molecules as tracers for positron emission tomography