Evaluation à l'échelle pilote d'un aérateur à cheminement prolongé

En vue d'optimiser l'aération de substrats liquides à forte charge organique dissoute, un système d'aération fonctionnant selon te principe du "cheminement prolongé" a été conçu et construit à l'échelle pilote (3 000 L). Le principe mis à l'essai consiste à injecter de l'air à la base de longs tuyaux enroulés. La dynamique hydraulique du système à cheminement prolongé a été caractérisée. Un système d'aération plus conventionnel, soit un injecteur d'air de type poreux, a été utilisé comme base de comparaison. Les performances d'oxygénation des deux systèmes ont été mesurées dans l'eau, sous les mêmes conditions, puis comparées entre elles et aux valeurs rapportées dans la littérature pour d'autres systèmes.Les principaux résultats montrent que le coefficient de transfert d'oxygène (KL.a) est bon à l'intérieur des tuyaux de l'aérateur à cheminement prolongé (jusqu'à 230 h-1). Le nouveau prototype démontre également une forte capacité d'emprisonnement de l'air puisque le gonflement atteint 20 %. Finalement, de bonnes efficacités énergétiques ont été obtenues : des valeurs brute de 1.9 kg O2/kWh et nette de 9.2 kg O2/kWh ont été atteintes. Le prototype, tel que construit, a offert des performances. d'oxygénation globales similaires à cettes démontrées par l'injecteur d'air de type poreux, le volume interne des tuyaux, qui présente un intérêt particulier pour le transfert d'oxygène, ne représentant que 26 % du volume liquide total.L'optimisation de l'aérateur à cheminement prolongé passe donc par l'accroissement maximal du volume interne des tuyaux par rapport au volume liquide total. Cette mesure se traduirait par une augmentation de la capacité d'oxygénation totale et des efficacités physique et énergétique du transfert d'oxygène, ainsi que par une diminution des puissances spécifiques requises.Les performances du système à cheminement prolone dans un liquide chargé en substrat organique restent à étudier, mais les résultats préliminaires obtenus dans l'eau du robinet sont encourageants.Aeration represents the major operating cost in the various aerobic treatment processes intended for wastewaters or other effluents showing a high dissolved organic load, such as swine manure; it is therefore necessary to maximize the utilization of the oxygen provided to any treatment system.Various types of air injectors and turbines have been studied or built in order to achieve an adequate oxygenation of liquid wastes to be treated : porous and non-porous injectors, immersed and surface turbines, the latter rotating vertically or horizontally. The aeration performances of these systems appear to be variable; moreover, these systems are not always well adapted to a substrate such as swine manure. With a view to possible application to swine manure treatment, we have designed an "extended contact" pilot-scale aerator (3000 L).The strategy involved injecting air at the basal end of long coiled pipes in which the manure to be treated was circulated. The objective was to increase the time of contact between the air bubbles and the liquid and, consequently, oxygen transfer to the latter. The internal surface of the pipes was large and could become an effective physical support for microbial attachment, thus promoting further digestion.We evaluated the performance of the system with tap water and compared it with a more conventional aeration system, i.e. a porous-type injector also known as a mini-bubble diffusor.Eight oxygenation parameters were evaluated for each of the two systems oxygen transfer coefficient (KL-a), swelling (SWEL), standard oxygenation capacity (SOC), specific standard oxygenation capacity (SSOC), physical efficiency of oxygen transfer [ɛ, cf. Equation (1)], power consumed (P), specific power injected (SP) and energy efficiency (E). A theoretical simulation of the performances of a hybrid system combining the two aeration principles was carried out. The hydraulic dynamics of the extended-contact system were established through the evaluation of the recirculated flows due to the aerator. The best results obtained were finally compared to those taken from the literature.The main results show the following positive aspects of the extended-contact aerator :1 - high oxygen transfer coefficients inside the pipes;2 - high air retention capacity;3 - good energy efficiency for low air flows.Inside the pipes, values of 230 h-1 were obtained for KL.a. The new prototype retained up to 546 L of air which corresponds to a swelling of 20 %. A raw energy efficiency of 1.9 kg O2/kWh was obtained, and the net value (based open the net power) was 9.2 kg O2/kWh.The prototype, as constructed, gave oxygenation performances globally similar to those obtained with the porous type air injector despite the fact that the internal volume of the pipes, which is of special interest for oxygen transfer, was only 26 % of the total liquid volume.The optimization of the extended-contact system therefore calls for a maximal increase of the internal volume of the pipes as compared to the total liquid volume. Ideally, the internal volume should represent 100 % of the total volume. By doing so, oxygenation performances should be improved because of :1 - increased total oxygenation capacity due to a better overall KL.a;2 - increased physical efficiency of oxygen transfer (ɛ) in relation to the length of the pipes (in theory, ɛ could reach 100 %);3 - decreased injected specific power (SP);4 - increased energy efficiency of oxygen transfer (E).With such improvements in view and considering the requirement : of the aerobic treatment of highly loaded affluents such as swine manure, the extended-contact aerator appears to be a promising aeration technique that still has, however, to be tested under practical conditions

Development of the item pool for the ‘WHO-ageism scale’:Conceptualisation, item generation, and content validity assessment

OBJECTIVES: ageism harms individuals' health and wellbeing and can be costly to societies. Reliable and valid measures that can quantify ageism are critical for achieving accurate data on its global prevalence, determinants and impacts, and to evaluate the effectiveness of interventions to reduce it. Ageism scales exist; however, none have been demonstrated to validly measure ageism in a manner consistent with consensus definitions of the concept (i.e. as manifested in all of stereotypes, prejudices and discrimination), whilst also quantifying ageism against all groups, from a target and perpetrator perspective, and across diverse country settings. Our objective was to develop an item pool to meet this need.METHODS: we completed the conceptualisation, item generation and content validity assessment phases of a new World Health Organisation (WHO) WHO-ageism item pool that aims to measure the multi-dimensional nature of ageism. These phases drew on a review of available evidence, an experts' workshop and structured content validity reviews conducted by experts in scale development and ageism drawn from every world region defined by WHO.RESULTS: our resulting item pool is designed to provide a multi-dimensional measure of ageism against all ages measured from both a perpetration and experienced perspective and that can produce valid and reliable scores within diverse country contexts and comparable scores across these contexts.CONCLUSIONS: our item pool is the first major step in providing a global and comprehensive measure of ageism. Future phases of research will refine the item pool and establish the statistical psychometric properties of the final tool

Contribution of a Disk Component to Single Peaked Broad Lines of Active Galactic Nuclei

We study the disk emission component hidden in the single-peaked Broad Emission Lines (BELs) of Active Galactic Nuclei (AGN). We compare the observed broad lines from a sample of 90 Seyfert 1 spectra taken from the Sloan Digital Sky Survey with simulated line profiles. We consider a two-component Broad Line Region (BLR) model where an accretion disk and a surrounding non-disk region with isotropic cloud velocities generate the simulated BEL profiles. The analysis is mainly based in measurements of the full widths (at 10%, 20% and 30% of the maximum intensity) and of the asymmetries of the line profiles. Comparing these parameters for the simulated and observed H$\alpha$ broad lines, we {found} that the hidden disk emission {may} be present in BELs even if the characteristic {of two peaked line profiles is} absent. For the available sample of objects (Seyfert 1 galaxies with single-peaked BELs), our study indicates that, {in the case of the hidden disk emission in single peaked broad line profiles}, the disk inclination tends to be small (mostly $i<25^\circ$) and that the contribution of the disk emission to the total flux should be smaller than the contribution of the surrounding region.Comment: 18 Figures, 1 Table, MNRAS-accepted. MNRAS-accepte

INCIDENCE OF PSYCHOTIC DISORDERS IN PALERMO: PRELIMINARY DATA

Background: The incidence of psychotic disorders varies in different geographical areas (McGrath 2004). Recent data suggest that the incidence is higher in males, migrant minorities and in urban areas. There aren\u2019t many available epidemiological data on the incidence of psychotic disorders in Italy. This is the first incidence study on psychotic disorders carried out in Palermo, the capital of Sicily. Methods: we screened all patients presenting with their first episode of psychosis to the mental health services of our catchment area (5 inpatient, 5 outpatient units and 3 private psychiatric hospitals) over a period of three years (2008-2011). The diagnosis of psychosis was defined using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN Wing, J. K., et al., 1990).The main socio-demographic data were collected using the MRC Social Data Schedule. When subjects were not available (did not consent) for interview, information was collected from clinical notes. The population at risk referred to the people aged from 18-65 who were resident in the same catchment area (Palermo Municipality) in the period considered, according to the data of the Statistic Office of Palermo Municipality). Results: we identified 216 patients affected by a first episode of psychosis (FEP): 135 M (62.5%) and 81 F (37.5%), mean age 31.42 years (SD: 11.44). 77.1% of FEP had a diagnosis of non affective psychosis, 12.8% of affective psychosis and 10.1% received a diagnosis of other psychosis. 204 subjects were Caucasian, 12 non Caucasian belonging to various ethnicities and they were all first generation migrants (4 Indian, 3 African, 2 Bangladeshi, and 3 Mixed). Population at risk is 425.194 people. The mean age of onset was lower in men than women M: 29.98 years (SD: 10.41) vs. F: 34.28 (SD:12.64) (p=0.013)The incidence of psychotic disorders in our catchment area is 16,9 per 100.000 person years. It was higher in men 21,9 per 100.000 than women 12,2 per 100.000. Discussion: Our study is the first epidemiological study in Sicily investigating the incidence of psychotic disorders. In our population men have a higher incidence of psychotic disorders than women and an earlier age of onset

Compton-thick AGN in the NuSTAR era III: A systematic study of the torus covering factor

We present the analysis of a sample of 35 candidate Compton thick (CT-) active galactic nuclei (AGNs) selected in the nearby Universe (average redshift ~0.03) with the Swift-BAT 100-month survey. All sources have available NuSTAR data, thus allowing us to constrain with unprecedented quality important spectral parameters such as the obscuring torus line-of-sight column density (N_{H, z}), the average torus column density (N_{H, tor}) and the torus covering factor (f_c). We compare the best-fit results obtained with the widely used MyTorus (Murphy et al. 2009) model with those of the recently published borus02 model (Balokovic et al. 2018) used in the same geometrical configuration of MyTorus (i.e., with f_c=0.5). We find a remarkable agreement between the two, although with increasing dispersion in N_{H, z} moving towards higher column densities. We then use borus02 to measure f_c. High-f_c sources have, on average, smaller offset between N_{H, z} and N_{H, tor} than low-f_c ones. Therefore, low f_c values can be linked to a "patchy torus" scenario, where the AGN is seen through an over-dense region in the torus, while high-f_c objects are more likely to be obscured by a more uniform gas distribution. Finally, we find potential evidence of an inverse trend between f_c and the AGN 2-10 keV luminosity, i.e., sources with higher f_c values have on average lower luminosities.Comment: 35 Pages, 23 Figures. Accepted for publication in Ap

Differing associations of BMI and body fat with asthma and lung function in children.

Current evidence suggests that in children there is a significant, albeit weak, association between asthma and obesity. Studies generally use body mass index (BMI) in evaluating body adiposity, but there are limitations to its use.Children from a population-based study attending follow-up (age 11 years) were weighed, measured and had percent body (PBF) and truncal (PTF) fat assessed using bioelectrical impedance. They were skin prick tested and completed spirometry. Parents completed a validated respiratory questionnaire. Children were defined as normal or overweight according to BMI and PBF cut-offs. We tested the association between these adiposity markers with wheeze, asthma, atopy, and lung-function.Six hundred forty-six children (339 male) completed follow-up. BMI z-score, PBF, and PTF were all positively associated with current wheeze (odds ratio [95% CI]: 1.27 [1.03, 1.57], P = 0.03; 1.05 [1.00, 1.09], P = 0.03; 1.04 [1.00, 1.08], P = 0.04, respectively). Similar trends were seen with asthma. However, when examining girls and boys separately, significant positive associations were found with PBF and PTF and asthma but only in girls (gender interaction P = 0.06 and 0.04, respectively). Associations between being overweight and wheezing and asthma were stronger when overweight was defined by PBF (P = 0.007, 0.03) than BMI (P > 0.05). Higher BMI was significantly associated with an increase in FEV(1) and FVC, but only in girls. Conversely, increasing body fat (PBF and PTF) was associated with reduced FEV(1) and FVC, but only in boys. No associations between adiposity and atopy were found.All adiposity measures were associated with wheeze, asthma, and lung function. However, BMI and PBF did not have the same effects and girls and boys appear to be affected differently

Risk of Population Extinction from Periodic and Abrupt Changes of Environment

A simulation model of a population having internal (genetic) structure is presented. The population is subject to selection pressure coming from the environment which is the same in the whole system but changes in time. Reproduction has a sexual character with recombination and mutation. Two cases are considered - oscillatory changes of the environment and abrupt ones (catastrophes). We show how the survival chance of a population depends on maximum allowed size of the population, the length of the genotypes characterising individuals, selection pressure and the characteristics of the climate changes, either their period of oscillations or the scale of the abrupt shift.Comment: 8 pages, 25 references, 10 figures; preliminary version to be submitted to Physica