Examining the Relationship Between Social Cohesion and Health in Kensington

This quantitative cross-sectional survey study was conducted in collaboration with the New Kensington Community Development Corporation (NKCDC) to improve our understanding of the role of social cohesion in the Somerset neighborhood. Its aims were to help guide future efforts to improve the health of this community by considering whether social factors might contribute to overall health. In previous studies, social cohesion has been hypothesized to be related to overall self-reported health. In this study we examined the nature and strength of this relationship in a low socio-economic status population in Kensington. We used linear regression to evaluate cross-sectional survey data collected from 328 neighborhood residents. Data was collected on health information, social cohesion, demographic factors, health behaviors, and financial stability. Variables that were significantly associated with self-reported health were included in a multiple regression model to examine the relationship between social cohesion and self-reported health. Our findings were that social cohesion and overall health were related. We also found that stress was significantly associated with social cohesion as well as overall health; while the reach of this study stops short of being able to identify the causality of these relationships, organizations such as NKCDC could combine the strength of the relationships with their expertise in the relevant population to better inform their future programming. This study also revealed a number of areas that could be worthy of future study, including the importance of collective efficacy in improving population health and the effect of social cohesion on people’s health over the course of a longitudinal study

The need for parity of protection

Julia Fossi explores the diverse interests of children and the rich lives they lead online. She argues that to reflect the modern experiences of children, steps must now be taken to equally protect them online and offline. Julia is Acting Head of Child Safety Online at the NSPCC, where she is responsible for all policy and the charity’s related programme of work in relation to child safety online. This includes issues such as online child sexual abuse, online harassment, hatred and bullying, and children’s access to adult content online

Are social networking sites doing enough to keep children safe?

Guest blogger Julia Fossi, Senior Analyst in the Child Safety Online Team at the NSPCC, explores whether the numerous stakeholders involved in child protection are doing enough to keep children safe in the online world. She introduces a new asset to help parents stay up to date with the latest sites, apps and games, Net Aware. Julia’s work focuses on social networking sites, peer-on-peer abuse online, and inappropriate and violent material

PROGRAMME D’ÉDUCATION BILINGUE SPÉCIAL (PEBS) AU CAMEROUN : ÉTAT DES LIEUX, OPPORTUNITÉS ET DÉFIS

This article explores and analyzes a new initiative in bilingual education, launched at the beginning of the 2009-2010 school year in certain secondary schools in Cameroon. The Special bilingual education programme (SBEP), which is still in its beginning phase, aims essentially at training students to communicate effectively and with as little anxiety as possible in the country’s two official languages, English and French. Upon examining the various reasons for the programme and the context in which it has been implemented, existing scientific research in second language acquisition points to the conclusion that the success of this most relevant programme would eventually lead to a complete remodelling of the French-English bilingual education system in Cameroon.DOI: http://dx.doi.org/10.11591/ijere.v2i4.292

Nondestructive biomarkers in ecotoxicology.

The aim of this article is to attempt a concise review of the state of the art of the nondestructive biomarkers approach in vertebrates, establishing a consensus on the most useful and sensitive nondestructive biomarker techniques, and proposing research priorities for the development and validation of this promising methodology. The following topics are discussed: the advantages of the use of nondestructive strategies in biomonitoring programs and the research fields in which nondestructive biomarkers can be applied; the biological materials suitable for nondestructive biomarkers and residue analysis in vertebrates; which biomarkers lend themselves to noninvasive techniques; and the validation and implementation strategy of the nondestructive biomarker approach. Examples of applications of this methodology in the hazard assessment of endangered species are also presented

Numerical simulations of stationary and transient spray combustion for aircraft gas turbine applications

Le développement des turbines à gaz d’aviation actuelles et futures est principalement axé sur la sécurité, la performance, la minimisation de la consommation de l’énergie, et de plus en plus sur la réduction des émissions d’espèces polluantes. Ainsi, les phases de design de moteurs sont soumises auxaméliorations continues par des études expérimentales et numériques. La présente thèse se consacre à l’étude numérique des phases transitoires et stationnaires de la combustion au sein d’une turbine à gaz d’aviation opérant à divers modes de combustion. Une attention particulière est accordée à la précision des résultats, aux coûts de calcul, et à la facilité de manipulation de l’outil numérique d’un point de vue industriel. Un code de calcul commercial largement utilisé en industrie est donc choisi comme outil numérique. Une méthodologie de Mécanique des Fluides Numériques (MFN) constituée de modèles avancés de turbulence et de combustion jumelés avec un modèle d’allumage sous-maille, est formulé pour prédire les différentes phases de la séquence d’allumage sous différentes conditions d’allumage par temps froid et de rallumage en altitude, ainsi que les propriétés de la flamme en régime stationnaire. Dans un premier temps, l’attention est focalisée sur le régime de combustion stationnaire. Trois méthodologies MFN sont formulées en exploitant trois modèles de turbulence, notamment, le modèle basé sur les équations moyennées de Navier-Stokes instationnaires (URANS), l’adaptation aux échelles de l’écoulement (SAS), et sur la simulation aux grandes échelles (LES). Pour évaluer la pertinence de l’incorporation d’un modèle de chimie détaillée ainsi que celle des effets de chimie hors-équilibre, deux différentes hypothèses sont considérées : l’hypothèse de chimie-infiniment-rapide à travers le modèle d’équilibre-partiel, et l’hypothèse de chimie-finie via le modèle de flammelettes de diffusion. Pour chacune des deux hypothèses, un carburant à une composante, et un autre à deux composantes sont utilisés comme substituts du kérosène (Jet A-1). Les méthodologies MFN résultantes sont appliquées à une chambre de combustion dont l’écoulement est stabilisé par l’effet swirl afin d’évaluer l’aptitude de chacune d’elle à prédire les propriétés de combustion en régime stationnaire. Par la suite, les rapports entre le coût de calcul et la précision des résultats pour les trois méthodologies MFN formulées sont explicitement comparés. La deuxième étude intermédiaire est dédiée au régime de combustion transitoire, notamment à la séquence d’allumage précédant le régime de combustion stationnaire. Un brûleur de combustibles gazeux, muni d’une bougie d’allumage, et dont la flamme est stabilisée par un accroche-flamme, est utilisé pour calibrer le modèle MFN formulé. Ce brûleur, de géométrie relativement simple, peut aider à la compréhension des caractéristiques d’écoulements réactifs complexes, en l’occurrence l’allumabilité et la stabilité. La méthodologie MFN la plus robuste issue de la précédente étude est reconsidérée. Puisque le brûleur fonctionne en mode partiellement pré-mélangé, le modèle de combustion paramétré par la fraction de mélange et la variable de progrès est adopté avec les hypothèses de chimie-infiniment-rapide et de chimie-finie, respectivement à travers le modèle de Bray-Moss-Libby (BML) et un modèle de flammelettes multidimensionnel (FGM). Le modèle d’allumage sous-maille est préalablement ajusté via l’implémentation des propriétés de la flamme considérée. Par la suite, le modèle d’allumage est couplé au solveur LES, puis successivement aux modèles BML et FGM. Pour évaluer les capacités prédictives des méthodologies résultantes, ces dernières sont utilisées pour prédire les évènements d’allumage résultant d’un dépôt d’énergie par étincelles à diverses positions du brûleur, et les résultats sont qualitativement et quantitativement validés en comparant ceux-ci à leurs homologues expérimentaux. Finalement, la méthodologie MFN validée en configuration gazeuse est étendue à la combustion diphasique en la couplant au module de la phase liquide, et en incorporant les propriétés de la flamme de kérosène dans le modèle d’allumage. La méthodologie MFN résultant de cette adaptation, est préalablement appliquée à la chambre de combustion étudiée antérieurement, pour prédire la séquence d’allumage et améliorer les prédictions antérieures des propriétés de la flamme en régime stationnaire. Par la suite, elle est appliquée à une chambre de combustion plus réaliste pour prédire des évènements d’allumage sous différentes conditions d’allumage par temps froid, et de rallumage en altitude. L’aptitude de la nouvelle méthodologie MFN à prédire les deux types d’allumage considérés est mesurée quantitativement et qualitativement en confrontant les résultats des simulations numériques avec les enveloppes d’allumage expérimentales et les images d’une séquence d’allumage enregistrée avec une caméra infrarouge.The development of current and future aero gas turbine engines is mainly focused on the safety, the performance, the energy consumption, and increasingly on the reduction of pollutants and noise level. To this end, the engine’s design phases are subjected to improving processes continuously through experimental and numerical investigations. The present thesis is concerned with the simulation of transient and steady combustion regimes in an aircraft gas turbine operating under various combustion modes. Particular attention is paid to the accuracy of the results, the computational cost, and the ease of handling the numerical tool from an industrial standpoint. Thus, a commercial Computational Fluid Dynamics (CFD) code widely used in industry is selected as the numerical tool. A CFD methodology consisting of its advanced turbulence and combustion models, coupled with a subgrid spark-based ignition model, is formulated with the final goal of predicting the whole ignition sequence under cold start and altitude relight conditions, and the main flame trends in the steady combustion regime. At first, attention is focused on the steady combustion regime. Various CFD methodologies are formulated using three turbulence models, namely, the Unsteady Reynolds-Averaged Navier-Stokes (URANS), the Scale-Adaptive Simulation (SAS), and the Large Eddy Simulation (LES) models. To appraise the relevance of incorporating a realistic chemistry model and chemical non-equilibrium effects, two different assumptions are considered, namely, the infinitely-fast chemistry through the partial equilibrium model, and the finite-rate chemistry through the diffusion flamelet model. For each of the two assumptions, both one-component and two-component fuels are considered as surrogates for kerosene (Jet A-1). The resulting CFD models are applied to a swirl-stabilized combustion chamber to assess their ability to retrieve the spray flow and combustion properties in the steady combustion regime. Subsequently, the ratios between the accuracy of the results and the computational cost of the three CFD methodologies are explicitly compared. The second intermediate study is devoted to the ignition sequence preceding the steady combustion regime. A bluff-body stabilized burner based on gaseous fuel, and employing a spark-based igniter, is considered to calibrate the CFD model formulated. This burner of relatively simple geometry can provide greater understanding of complex reactive flow features, especially with regard to ignitability and stability. The most robust of the CFD methodologies formulated in the previous configuration is reconsidered. As this burner involves a partially-premixed combustion mode, a combustion model based on the mixture fraction-progress variable formulation is adopted with the assumptions of infinitely-fast chemistry and finite-rate chemistry through the Bray-Moss-Libby (BML) and Flamelet Generated Manifold (FGM) models, respectively. The ignition model is first customized by implementing the properties of the flame considered. Thereafter, the customized ignition model is coupled to the LES solver and combustion models based on the two above-listed assumptions. To assess the predictive capabilities of the resulting CFD methodologies, the latter are used to predict ignition events resulting from the spark deposition at various locations of the burner, and the results are quantitatively and qualitatively validated by comparing the latter to their experimental counterparts. Finally, the CFD methodology validated in the gaseous configuration is extended to spray combustion by first coupling the latter to the spray module, and by implementing the flame properties of kerosene in the ignition model. The resulting CFD model is first applied to the swirl-stabilized combustor investigated previously, with the aim of predicting the whole ignition sequence and improving the previous predictions of the combustion properties in the resulting steady regime. Subsequently, the CFD methodology is applied to a scaled can combustor with the aim of predicting ignition events under cold start and altitude relight operating conditions. The ability of the CFD methodology to predict ignition events under the two operating conditions is assessed by contrasting the numerical predictions to the corresponding experimental ignition envelopes. A qualitative validation of the ignition sequence is also done by comparing the numerical ignition sequence to the high-speed camera images of the corresponding ignition event

Food security policy choices: A review of the usefulness of public policy taxonomies

This paper addresses the "dependent variable" problem in food security policies, namely the difficulty in classifying food security  policies that limits comparative policy studies. Policy comparisons require criteria that are general enough for broad application butsensitive to the context. A rigorous and objective basis for comparisons would allow for studying how policies, and food security policies in particular, emerge. This is important in Africa as, in the past, food security and nutrition crises have been attributed to thefailure of government policies. This paper reviews the main key available public policy classifications based on their predictability, mutual-exclusivity and relevance. These include Lowi's and Wilson's typologies, the agricultural policies' classification by Norton and the FAO-FAPDA classification. The review found that available typologies do not accommodate multi-sectoral actions and are not entirely applicable to food security public policy classification. The domain shift from food policy to food security, and more recently to food systems demands that all elements in the food system to be taken into consideration in the policy process. This limits the use of policies as "dependent variables" and hence the study of how they emerge, particularly in Africa. A critique of available policy classes shows that these cannot be treated as "dependent variables". It is argued that a potential solution to the "dependent variable" problem of food security policies lies in the development of a taxonomy, simplifying their complexity with analytical shortcuts. Having reviewed Candel and Daugbjergs’ recent taxonomy, refinements are proposed to be applied in the African context. The proposed taxonomy represents an alternative to classify food security policies in Africa along four core dimensions. This classification offers prospects for researchers to study what factors drives policy-classes in one direction or the other, along the four dimensions. Althoughthe scales and calibration of the four dimensions will need to be developed and tested, the proposed typology offers a way to treat the dimensions as “dependent variables”. Key words: policy-classification, food-security policy, food systems s, policy-taxonomy, Lowi, Wilson, dependent variable problem, Afric