Search results for "RETENTION"
showing 10 items of 347 documents
Grade repetition at primary school level "CP"
2005
This research on the grade retention to the CP erects a detailed inventory of the knowledge on this question which gives rise to the more of animated discussions between the researchers and the teachers, and this since a long time. By allying the historic, comparative, economical and educational approaches, she conveys principal empirical results attached to the many facets of this measure that is more than an educational done. The empirical contribution of this study is based on a longitudinal followed during two years about more than three thousand students on CP in public schools of the French department of the Côte d'Or. We highlight that the grade retention are received favourably by t…
Performance of a membrane-coupled high-rate algal pond for urban wastewater treatment at demonstration scale
2020
[EN] The objective of this study was to evaluate the performance of an outdoor membrane-coupled high-rate algal pond equipped with industrial-scale membranes for treating urban wastewater. Decoupling biomass retention time (BRT) and hydraulic retention time (HRT) by membrane filtration resulted in improved process efficiencies, with higher biomass productivities and nutrient removal rates when operating at low HRTs. At 6 days of BRT, biomass productivity increased from 30 to 66 and to 95 g.m(-3).d(-1) when operating at HRTs of 6, 4 and 2.5 days, respectively. The corresponding nitrogen removal rates were 4, 8 and 11 g N.m(-3).d(-1) and the phosphorous removal rates were 0.5, 1.3 and 1.6 g P…
How composition and process parameters affect volatile active compounds in biopolymer films
2012
Abstract Active edible films based on chitosan and containing an active aroma compound have been investigated. The influence of the composition of the film forming solution (solvent, plasticizers, nanoparticles, emulsifiers and aroma traps) and process parameters (temperature and viscosity) on drying kinetics, water content, colour, aroma compound retention and partition coefficient was studied. Solvent evaporation rate was increased by addition of ethanol. Water evaporation was delayed by glycerol. The aroma retention during film drying was directly related to the water content. The drying temperature had opposite influences according to the composition of the solvent and additives. Increa…
How and why does willow biochar increase a clay soil water retention capacity?
2018
Addition of biochar into a soil changes its water retention properties by modifying soil textural and structural properties. In addition, internal micrometer-scale porosity that is able to directly store readily plant available water affects soil water retention properties. This study shows how precise knowledge of the internal micrometer-scale pore size distribution of biochar can deepen the understanding of the biochar-water interactions in soils. The micrometer-scale porosity of willow biochar was quantitatively and qualitatively characterized using X-ray tomography, 3D image analysis and Helium ion microscopy. The effect of biochar application on clay soil water retention was studied by…
Effects of Grade Retention Policies: A Literature Review of Empirical Studies Applying Causal Inference
2021
The identification of the causal effects of grade retention policies is of enormous relevance for researchers and policymakers alike. Taking advantage of the availability of more detailed longitudinal datasets, researchers have been able to apply different identification strategies that address the classical problems of selection bias and unobserved heterogeneity that have plagued previous studies on the effect of retention. We present a systematic literature review of empirical studies aiming to unveil the causal effects of retention. This study underlines the need to consider and evaluate different kinds of grade retention polices as their effects vary depending on several dimensions (suc…
Analysis of Biomass Characteristics in MBR and MB-MBR Systems Fed with Synthetic Wastewater: Influence of a Gradual Salinity Increase
2014
The paper presents the results of a field gathering campaign carried out on two different pilot scale membrane bioreactor (MBR) systems, treating synthetic wastewater subject to a gradual increase of salinity. One was a conventional MBR system, while the other was a moving bed biofilm membrane bioreactor (MB-MBR), which combines suspended biomass and biofilm. Indeed, the presence of suspended carriers inside the bioreactor seems to give benefits due to the collisions between the circulating media and the membrane. The aim of the study was the comparison of two configurations in terms of biomass activity characterization and performance (pollutants removal and hydraulic behaviour). The resul…
Are mucous retention cysts and pseudocysts in the maxillary sinus a risk factor for dental implants? A systematic review
2020
Background Mucous retention cysts and pseudocysts of the maxillary sinus are benign lesions present in up to 13% of adult patients. Different surgical approaches for sinus lift and dental implant placement in the presence of these lesions have been proposed. Material and Methods A systematic review was performed following the PRISMA statement recommendations to answer the PICO question: Does the aspiration or removal of mucous retention cysts/pseudocysts before or during sinus lifting and dental implant placing, affect the survival of the implants? The study was pre-registered in PROSPERO (CRD42020185528). Included articles quality was assessed using the “NIH quality assessment tool” and “T…
Linking service structural complexity to customer satisfaction
2001
The literature shows a paradox in the understanding of the relationship between structural complexity (defined as the diversity of services offered by an organization) and customer satisfaction. Structural complexity tends to be a popular strategy designed to satisfy different customer needs. However, a negative relationship between structural complexity and customer satisfaction has also been argued. Based on the research on the public versus private distinction, this paper proposes that type of ownership is associated with the paradox mentioned, moderating the relationship between structural complexity and customer satisfaction. The authors tested this hypothesis using a sample of 60 mana…
Implicit learning of a repeated segment in continuous tracking: A reappraisal
2006
Several prior studies (e.g., Shea, Wulf, Whitacre, & Park, 2001; Wulf & Schmidt, 1997) have apparently demonstrated implicit learning of a repeated segment in continuous-tracking tasks. In two conceptual replications of these studies, we failed to reproduce the original findings. However, these findings were reproduced in a third experiment, in which we used the same repeated segment as that used in the Wulf et al. studies. Analyses of the velocity and the acceleration of the target suggests that this repeated segment could be easier to track than the random segments serving as control, accounting for the results of Wulf and collaborators. Overall these experiments suggest that lea…
Extraprostatic Spindle Cell Stromal Tumor of the Prostate: Case Report
2007
Several benign and malignant nonepithelial and stromal-like lesions arise in the prostate. Because such lesions are rare, their recognition is essential, because treatment and prognosis depend on an adequate pathohistologic classification. We report a case of an 83-year-old man with a stromal tumor of the prostate of uncertain malignant potential (STUMP). He presented with urinary retention and rectal constipation. On bimanual examination, a rectally and suprapubically palpable mass was found. Imaging studies revealed a 12 x 8 cm pararectal inhomogeneous mass of uncertain origin compressing rectum and urethra. The tumor was resected by a retropubic approach and examined immunohistochemicall…