Proposal for a Noninterferometric Test of Collapse Models in Optomechanical Systems

The test of modifications to quantum mechanics aimed at identifying the fundamental reasons behind the unobservability of quantum mechanical superpositions at the macroscale is a crucial goal of modern quantum mechanics. Within the context of collapse models, current proposals based on interferometric techniques for their falsification are far from the experimental state of the art. Here we discuss an alternative approach to the testing of quantum collapse models that, by bypassing the need for the preparation of quantum superposition states might help us addressing nonlinear stochastic mechanisms such as the one at the basis of the continuous spontaneous localization model. 

Physical Characterisation of Fast-Rotating Near-Earth Asteroids

We present VLT+VISIR mid-IR observations of fast-rotating near-Earth asteroids. Diameters and albedos are determined with thermal models. These NEAs may have unusual surface properties, e.g. from regolith transport/stripping due to the YORP effect.

Pathways Project Final Report Volume 1: Field Investigation and Catchment Conceptual Models

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Executive Summary
The Pathways Project field studies were targeted at improving the understanding of contaminant transport along different hydrological pathways in Irish catchments, including their associated impacts on water quality and river ecology. The contaminants of interest were phosphorus, nitrogen and sediment. The working Pathways conceptual model included overland flow, interflow, shallow groundwater flow, and deep groundwater flow. This research informed the development of a set of Catchment Management Support Tools (CMSTs) comprising an Exploratory Tool, Catchment Characterization Tool (CCT) and Catchment Modelling Tool (CMT) as outlined in Pathways Project Final Reports Volumes 3 and 4.
In order to inform the CMST, four suitable study catchments were selected following an extensive selection process, namely the Mattock catchment, Co. Louth/Meath; Gortinlieve catchment, Co. Donegal; Nuenna catchment, Co. Kilkenny and the Glen Burn catchment, Co. Down. The Nuenna catchment is well drained as it is underlain by a regionally important karstified limestone aquifer with permeable limestone tills and gravels, while the other three catchments are underlain by poorly productive aquifers and low permeability clayey tills, and are poorly drained.
All catchments were instrumented, and groundwater, surface and near-surface water and aquatic ecology were monitored for a period of two years. Intensive water quality sampling during rainfall events was used to investigate the pathways delivering nutrients. The proportion of flow along each pathway was determined using chemical and physical hydrograph separation techniques, supported by numerical modelling.
The outcome of the field studies broadly supported the use of the initial four-pathway conceptual model used in the Pathways CMT (time-variant model). The artificial drainage network was found to be a significant contributing pathway in the poorly drained catchments, at low flows and during peak flows in wet antecedent conditions. The transition zone (TZ), i.e. the broken up weathered zone at the top of the bedrock, was also found to be an important pathway. It was observed to operate in two contrasting hydrogeological scenarios: in groundwater discharge zones the TZ can be regarded as being part of the shallow groundwater pathway, whereas in groundwater recharge zones it behaves more like interflow.
In the catchments overlying poorly productive aquifers, only a few fractures or fracture zones were found to be hydraulically active and the TZ, where present, was the main groundwater pathway. In the karstified Nuenna catchment, the springs, which are linked to conduits as well as to a diffuse fracture network, delivered the majority of the flow. These findings confirm the two-component groundwater contribution from bedrock but suggest that the size and nature of the hydraulically active fractures and the nature of the TZ are the dominant factors at the scale of a stream flow event.
Diffuse sources of nitrate were found to be typically delivered via the subsurface pathways, especially in the TZ and land drains in the poorly productive aquifer catchments, and via the bedrock groundwater in the Nuenna. Phosphorus was primarily transported via overland flow in both particulate and soluble forms. Where preferential flow paths existed in the soil and subsoil, soluble P, and to a lesser extent particulate P, were also transported via the TZ and in drains and ditches. Arable land was found to be the most important land use for
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the delivery of sediment, although channel bank and in-stream sources were the most significant in the Glen Burn catchment. Overland flow was found to be the predominant transport sediment pathway in the poorly productive catchments. These findings informed the development of the transport and attenuation equations used in the CCT and CMT. From an assessment of the relationship between physico-chemical and biological conditions, it is suggested that in the Nuenna, Glen Burn and Gortinlieve catchments, a relationship may exist between biological water quality and nitrogen concentrations, as well as with P. In the Nuenna, there was also a relationship between macroinvertebrate status and alkalinity.
Further research is recommended on the transport and delivery of phosphorus in groundwater, the transport and attenuation dynamics in the TZ in different hydrogeological settings and the relationship between macroinvertebrates and co-limiting factors. High resolution temporal and spatial sampling was found to be important for constraining the conceptual understanding of nutrient and sediment dynamics which should also be considered in future studies.

Home and Workplace Built Environment Supports for Physical Activity

BACKGROUND: Physical inactivity has been associated with obesity and related chronic diseases. Understanding built environment (BE) influences on specific domains of physical activity (PA) around homes and workplaces is important for public health interventions to increase population PA.

PURPOSE: To examine the association of home and workplace BE features with PA occurring across specific life domains (work, leisure, and travel).

METHODS: Between 2012 and 2013, telephone interviews were conducted with participants in four Missouri metropolitan areas. Questions included sociodemographic characteristics, home and workplace supports for PA, and dietary behaviors. Data analysis was conducted in 2013; logistic regression was used to examine associations between BE features and domain-specific PA.

RESULTS: In home neighborhoods, seven of 12 BE features (availability of fruits and vegetables, presence of shops and stores, bike facilities, recreation facilities, crime rate, seeing others active, and interesting things) were associated with leisure PA. The global average score of home neighborhood BE features was associated with greater odds of travel PA (AOR=1.99, 95% CI=1.46, 2.72); leisure PA (AOR=1.84, 95% CI=1.44, 2.34); and total PA (AOR=1.41, 95% CI=1.04, 1.92). Associations between workplace neighborhoods' BE features and workplace PA were small but in the expected direction.

CONCLUSIONS: This study offers empirical evidence on BE supports for domain-specific PA. Findings suggest that diverse, attractive, and walkable neighborhoods around workplaces support walking, bicycling, and use of public transit. Public health practitioners, researchers, and worksite leaders could benefit by utilizing worksite domains and measures from this study for future BE assessments.

Characterization of the toxic potential of nanomaterials using in vitro cell models

Os nanomateriais são estruturas com uma ou mais dimensões inferiores a 100 nanómetros. Devido à sua pequena dimensão, as nanopartículas apresentam atributos únicos, tais como a sua elevada área superficial relativamente à sua massa, reactividade ou força tênsil. Estas características influenciam grandemente algumas das propriedades dos nanomateriais, como a sua hidrofobicidade, carga ou toxicidade. As propriedades das nanopartículas tornam-nas também muito úteis para o Homem, sendo aplicadas em medicina, farmácia, electrónica, cosmética, vestuário e biotecnologia, entre outras. O aumento de produção e utilização de nanomateriais tem vindo a aumentar também a possibilidade de exposição humana a este tipo de partículas, levando a preocupações relativas ao risco de toxicidade aguda ou crónica. A exposição humana pode ocorrer por diversas vias, sendo as mais relevantes a via inalatória, ingestão ou contacto com a pele. Dependendo do material e do órgão-alvo, a exposição a nanomateriais pode conduzir a diferentes consequências biológicas: a nível dos órgãos, os nanomateriais podem levar a inflamação ou a supressão do sistema imunitário e, a nível celular e molecular, a perturbações na estrutura e integridade do genoma, assim como a interacções com moléculas biológicas e inibição da actividade proteica, entre outras consequências. Um dos nanomateriais mais utilizados são os nanotubos de carbono. Estes são constituídos por grafite cilíndrica disposta numa única camada (designados nanotubos de carbono de parede simples) ou em várias (nanotubos de carbono de parede múltipla). Os nanotubos de carbono apresentam propriedades como resistência e condutividade que os tornam muito úteis em aplicações como aparelhos electrónicos, vestuário ou biomedicina; cada vez mais, portanto, se torna provável a exposição ocupacional ou ambiental a este material. A semelhança estrutural destas partículas com fibras de amianto conduziu a questões relativas à sua segurança, pelo que já foram elaborados diversos estudos relativos aos seus efeitos biológicos. Alguns trabalhos sugerem que os nanotubos de carbono têm a capacidade de produzir toxicidade associada a lesões físicas, à produção de danos oxidativos por interacção com mecanismos celulares, ou a morte celular. Outros trabalhos defendem que estas partículas não causam toxicidade relevante. O projecto de dimensão europeia “NANoREG” surgiu da necessidade de ser desenvolvida legislação e regulamentação apoiadas em conhecimento científico e adequadas à produção e ao uso actual de nanomateriais. Este trabalho teve como objectivos principais a determinação do potencial cito- e genotóxico de um conjunto de nanotubos de carbono de parede múltipla (designados NM-400 a NM-403), e a consequente tentativa de associar este potencial às características físico-químicas dos nanomateriais. Com este objectivo, a exposição por via inalatória foi analisada, pelo uso de duas linhas celulares in vitro provenientes de tecidos do tracto respiratório: epitélio pulmonar (células A549) e epitélio brônquico (células BEAS-2B). A citotoxicidade dos nanotubos de carbono foi analisada com base em três parâmetros. Em primeiro lugar, as células foram contadas após a exposição aos nanomateriais utilizando o corante azul de tripanao para excluir as células inviáveis; a contagem foi realizada 3 e 24 horas após a exposição das células aos nanotubos. Os resultados deste ensaio apontam para a ausência de citotoxicidade após a exposição mais curta, e dados inconsistentes após a mais longa. Em segundo lugar, foi realizado o ensaio clonogénico, que se baseia na capacidade das células de se dividirem após a exposição ao agente em estudo. Este ensaio só foi realizado nas células A549 pois as BEAS-2B não permitem a formação de colónias. Os resultados apontam para uma citotoxicidade após a exposição a todos os nanomateriais, cuja intensidade se relaciona directamente com o tamanho das partículas, assim como ao seu diâmetro e área de superfície. Em terceiro lugar, foram calculados dois índices de viabilidade no ensaio dos Micronúcleos, cujo objectivo é avaliar se as células se dividiram durante a exposição aos nanomateriais em comparação com o controlo, e cujos resultados apresentam incoerências em relação aos outros já referidos. Estes dados podem ser justificados pelas diferenças existentes entre os ensaios, como o tempo de exposição ou a densidade celular. Os efeitos genotóxicos dos nanomateriais foram avaliados com recurso aos ensaios do cometa e dos micronúcleos. O primeiro detecta lesões pequenas e reversíveis nas cadeias de DNA, ao passo que o segundo detecta efeitos irreversíveis ao nível cromossómico, tais como quebras ou perdas de cromossomas. Os resultados do ensaio do cometa sugerem que nenhum dos nanomateriais testados é genotóxico, uma vez que em ambas as linhas celulares e em ambos os tempos de exposição, os resultados são negativos. O ensaio dos micronúcleos, por outro lado, aponta para existência de genotoxicidade de dois dos nanomateriais (NM-401 e NM-402) nas células A549, mas não em células BEAS-2B. Uma possível explicação para estes dados aparentemente contraditórios pode residir na hipótese de estes nanotubos de carbono serem compostos com efeitos aneugénicos, mas não clastogénicos: o ensaio dos micronúcleos permite a detecção de ambos os mecanismos de acção, ao passo que o ensaio do cometa só revela a quebra de cadeias de DNA. Outra justificação para os resultados é a possível influência da perda de viabilidade das células analisadas. Com base nos dados do ensaio clonogénico, estas partículas apresentam elevada citotoxicidade, pelo que os resultados dos ensaios de genotoxicidade, em particular do Ensaio do Cometa, poderão ser afectados por estes efeitos. O meio de cultura usado para expor as células aos nanomateriais também é um parâmetro muito relevante na sua toxicidade. Neste trabalho, foram usados meios de cultura com proteínas, que podem ser adsorvidas pelas partículas e formar uma “corona” em seu redor; este processo pode alterar propriedades importantes dos nanomateriais, entre os quais o seu potencial efeito biológico. Também o método usado para conseguir uma dispersão homogénea de nanomateriais pode conduzir a diferenças nos resultados dos ensaios de toxicidade. Neste estudo, foram observados alguns problemas relativos à perda de homogeneidade das dispersões de nanotubos de carbono, o que pode ter conduzido a que as células fossem expostas a massas de partículas de grandes dimensões conjuntamente com partículas individualizadas. O período durante o qual as células são expostas ao nanomaterial é também um aspecto essencial na produção de efeitos tóxicos. Resumindo, este projecto forneceu informações relativas à toxicidade dos nanotubos de carbono que, complementadas pelas conclusões dos restantes parceiros do projecto europeu, poderão contribuir significativamente para a avaliação de risco e criação de legislação relativamente à utilização de nanomateriais. Na linha celular BEAS-2B, nenhum destes nanomateriais parece produzir efeitos tóxicos, quer a nível de célula, quer a nível de genoma, nas condições experimentais utilizadas. Nas células A549, por outro lado, os três nanomateriais testados parecem ser acentuadamente citotóxicos, e dois deles (NM-401 e NM-402) são também genotóxicos. Em relação a perspectivas futuras, pode-se concluir que nem todos os ensaios de toxicidade existentes actualmente são adequados à análise de nanopartículas, pelo que novas metodologias devem ser desenvolvidas e complementadas por ensaios in vivo. Todos os estudos envolvendo nanomateriais deverão também descrever as características físico-químicas dos materiais usados, de forma a se poderem comparar os resultados com os de outros trabalhos.

Cultural journalism in a digital environment : new models, practices and possibilities

Both culture coverage and digital journalism are contemporary phenomena that have undergone several transformations within a short period of time. Whenever the media enters a period of uncertainty such as the present one, there is an attempt to innovate in order to seek sustainability, skip the crisis or find a new public. This indicates that there are new trends to be understood and explored, i.e., how are media innovating in a digital environment? Not only does the professional debate about the future of journalism justify the need to explore the issue, but so do the academic approaches to cultural journalism. However, none of the studies so far have considered innovation as a motto or driver and tried to explain how the media are covering culture, achieving sustainability and engaging with the readers in a digital environment. This research examines how European media which specialize in culture or have an important cultural section are innovating in a digital environment. Specifically, we see how these innovation strategies are being taken in relation to the approach to culture and dominant cultural areas, editorial models, the use of digital tools for telling stories, overall brand positioning and extensions, engagement with the public and business models. We conducted a mixed methods study combining case studies of four media projects, which integrates qualitative web features and content analysis, with quantitative web content analysis. Two major general-interest journalistic brands which started as physical newspapers – The Guardian (London, UK) and Público (Lisbon, Portugal) – a magazine specialized in international affairs, culture and design – Monocle (London, UK) – and a native digital media project that was launched by a cultural organization – Notodo, by La Fábrica – were the four case studies chosen. Findings suggest, on one hand, that we are witnessing a paradigm shift in culture coverage in a digital environment, challenging traditional boundaries related to cultural themes and scope, angles, genres, content format and delivery, engagement and business models. Innovation in the four case studies lies especially along the product dimensions (format and content), brand positioning and process (business model and ways to engage with users). On the other hand, there are still perennial values that are crucial to innovation and sustainability, such as commitment to journalism, consistency (to the reader, to brand extensions and to the advertiser), intelligent differentiation and the capability of knowing what innovation means and how it can be applied, since this thesis also confirms that one formula doesn´t suit all. Changing minds, exceeding cultural inertia and optimizing the memory of the websites, looking at them as living, organic bodies, which continuously interact with the readers in many different ways, and not as a closed collection of articles, are still the main challenges for some media.

Daily physical activities and sports in adult survivors of childhood cancer and healthy controls: a population-based questionnaire survey.

BACKGROUND: Healthy lifestyle including sufficient physical activity may mitigate or prevent adverse long-term effects of childhood cancer. We described daily physical activities and sports in childhood cancer survivors and controls, and assessed determinants of both activity patterns. METHODOLOGY/PRINCIPAL FINDINGS: The Swiss Childhood Cancer Survivor Study is a questionnaire survey including all children diagnosed with cancer 1976-2003 at age 0-15 years, registered in the Swiss Childhood Cancer Registry, who survived ≥5 years and reached adulthood (≥20 years). Controls came from the population-based Swiss Health Survey. We compared the two populations and determined risk factors for both outcomes in separate multivariable logistic regression models. The sample included 1058 survivors and 5593 controls (response rates 78% and 66%). Sufficient daily physical activities were reported by 52% (n = 521) of survivors and 37% (n = 2069) of controls (p<0.001). In contrast, 62% (n = 640) of survivors and 65% (n = 3635) of controls reported engaging in sports (p = 0.067). Risk factors for insufficient daily activities in both populations were: older age (OR for ≥35 years: 1.5, 95CI 1.2-2.0), female gender (OR 1.6, 95CI 1.3-1.9), French/Italian Speaking (OR 1.4, 95CI 1.1-1.7), and higher education (OR for university education: 2.0, 95CI 1.5-2.6). Risk factors for no sports were: being a survivor (OR 1.3, 95CI 1.1-1.6), older age (OR for ≥35 years: 1.4, 95CI 1.1-1.8), migration background (OR 1.5, 95CI 1.3-1.8), French/Italian speaking (OR 1.4, 95CI 1.2-1.7), lower education (OR for compulsory schooling only: 1.6, 95CI 1.2-2.2), being married (OR 1.7, 95CI 1.5-2.0), having children (OR 1.3, 95CI 1.4-1.9), obesity (OR 2.4, 95CI 1.7-3.3), and smoking (OR 1.7, 95CI 1.5-2.1). Type of diagnosis was only associated with sports. CONCLUSIONS/SIGNIFICANCE: Physical activity levels in survivors were lower than recommended, but comparable to controls and mainly determined by socio-demographic and cultural factors. Strategies to improve physical activity levels could be similar as for the general population.

Relationship of physical activity with motor skills, aerobic fitness and body fat in preschool children: a cross-sectional and longitudinal study (Ballabeina).

Adiposity, low aerobic fitness and low levels of activity are all associated with clustered cardiovascular disease risk in children and their high prevalence represents a major public health concern. The aim of this study is to investigate the relationship of objectively measured physical activity (PA) with motor skills (agility and balance), aerobic fitness and %body fat in young children. This study is a cross-sectional and longitudinal analyses using mixed linear models. Longitudinal data were adjusted for baseline outcome parameters. In all, 217 healthy preschool children (age 4-6 years, 48% boys) participated in this study. PA (accelerometers), agility (obstacle course), dynamic balance (balance beam), aerobic fitness (20-m shuttle run) and %body fat (bioelectric impedance) at baseline and 9 months later. PA was positively associated with both motor skills and aerobic fitness at baseline as well as with their longitudinal changes. Specifically, only vigorous, but not total or moderate PA, was related to changes in aerobic fitness. Higher PA was associated with less %body fat at baseline, but not with its change. Conversely, baseline motor skills, aerobic fitness or %body fat were not related to changes in PA. In young children, baseline PA was associated with improvements in motor skills and in aerobic fitness, an important determinant of cardiovascular risk.

Reduced physical activity level and cardiorespiratory fitness in children with chronic diseases.

We aimed to compare physical activity level and cardiorespiratory fitness in children with different chronic diseases, such as type 1 diabetes mellitus (T1DM), obesity (OB) and juvenile idiopathic arthritis (JIA), with healthy controls (HC). We performed a cross-sectional study including 209 children: OB: n = 45, T1DM: n = 48, JIA: n = 31, and HC: n = 85. Physical activity level was assessed by accelerometer and cardiorespiratory fitness by a treadmill test. ANOVA, linear regressions and Pearson correlations were used. Children with chronic diseases had reduced total daily physical activity counts (T1DM 497 +/- 54 cpm, p = 0.003; JIA 518 +/- 28, p < 0.001, OB 590 +/- 25, p = 0.003) and cardiorespiratory fitness (JIA 39.3 +/- 1.7, p = 0.001, OB 41.7 +/- 1.2, p = 0.020) compared to HC (668 +/- 35 cpm; 45.3 +/- 0.9 ml kg(-1) min(-1), respectively). Only 60.4% of HC, 51.6% of OB, 38.1% of JIA and 38.5% of T1DM children met the recommended daily 60 min of moderate-to-vigorous physical activity. Low cardiorespiratory fitness was associated with female gender and low daily PA. Children with chronic diseases had reduced physical activity and cardiorespiratory fitness. As the benefits of PA on health have been well demonstrated during growth, it should be encouraged in those children to prevent a reduction of cardiorespiratory fitness and the development of comorbidities.

Physical volcanology, sedimentology, stratigraphy and petrochemistry of the Berry Creek metavolcanics: an Archean calc-alkaline complex, Lake of the Woods, Ontario

The steeply dipping, isoclinally folded early Precambrian (Archean) Berry Creek Metavolcanic Complex comprises primary to resedimented pyroclastic, epiclastic and autoclastic deposits. Tephra erupted from central volcanic edifices was dumped by mass flow mechanisms into peripheral volcanosedimentary depressions. Sedimentation has been essentially contemporaneous with eruption and transport of tephra. The monolithic to heterolithic tuffaceous horizons are interpreted as subaerial to subaqueous pumice and ash flows, secondary debris flows, lahars, slump deposits and turbidites. Monolithic debris flows, derived from crumble breccia and dcme talus, formed during downslope collapse and subsequent gravity flowage. Heterolithic tuff, lahars and lava flow morphologies suggest at least temporary emergence of the edifice. Local collapse may have accompanied pyroclastic volcanism. The tephra, produced by hydromagmatic to magmatic eruptions, were rapidly transported, by primary and secondary mechanisms, to a shallow littoral to deep water subaqueous fan developed upon the subjacent mafic metavolcanic platform. Deposition resulted from traction, traction carpet, and suspension sedimentation from laminar to turbulent flows. Facies mapping revealed proximal (channel to overbank) to distal facies epiclastics (greywackes, argillite) intercalated with proximal vent to medial fan facies crystal rich ash flows, debris flows, bedded tuff and shallow water to deep water lava flows. Framework and matrix support debris flows exhibit a variety of subaqueous sedimentary structures, e.g., coarse tail grading, double grading, inverse to normal grading, graded stratified pebbly horizons, erosional channels. Pelitic to psammitic AE turbidites also contain primary stru~tures, e.g., flames, load casts, dewatering pipes. Despite low to intermediate pressure greenschist to amphibolite grade metamorphism and variably penetrative deformation, relicts of pumice fragments and shards were recognized as recrystallized quartzofeldspathic pseudomorphs. The mafic to felsic metavolcanics and metasediments contain blasts of hornblende, actinolite, garnet, pistacitic epidote, staurolite, albitic plagioclase, and rarely andalusite and cordierite. The mafic metavolcanics (Adams River Bay, Black River, Kenu Lake, Lobstick Bay, Snake Bay) display _holeiitic trends with komatiitic affinities. Chemical variations are consistent with high level fractionation of olivine, plagioclase, amphibole, and later magnetite from a parental komatiite. The intermediate to felsic (64-74% Si02) metavolcanics generally exhibit calc-alkaline trends. The compositional discontinuity, defined by major and trace element diversity, can be explained by a mechanism involving two different magma sources. Application of fractionation series models are inconsistent with the observed data. The tholeiitic basalts and basaltic andesites are probably derived by low pressure fractionation of a depleted (high degree of partial melting) mantle source. The depleted (low Y, Zr) calc-alkaline metavolcanics may be produced by partial melting of a geochemically evolved source, e.g., tonalitetrondhjemite, garnet amphibolite or hydrous basalt.

Examining the role of goals and motives for physical activity and eating behaviour in commercial weight-loss program participants

Background: The purpose of this study was to examine the relationships between physical activity and healthy eating behaviour with the participant's motives and goals for each health behaviour. Methods: Participants (N 121; 93.2% female) enrolled in commercial weightloss programs at the time of data collection, completed self-reported instruments using a web-based interface that were in accordance with Deci and Ryan's (2002) Self-Determination Theory (SDT). Results: Multiple linear regression models revealed that motivation and goals collectively accounted for between 0.21 to 0.29 percent and 0.03 to 0.16 percent of the variance in physical and healthy eating behaviours in this sample. In general, goals regarding either behaviour did not appear to have strong predictive relationships with each health behaviour beyond the contributions of motives. Discussion: Overall, findings from this study suggest that motives seem to mattermore than goals for both physical activity and healthy eating behaviour in clientele of commercial weight-loss programs. Therefore commercial weight-loss program implementers may want to consider placing more attention on motives I than goals for their clientele when designing weight-loss and weight-maintenance initiatives.

Participation in leisure and physical activity among children and adolescents with juvenile idiopathic arthritis

Contexte: L’arthrite juvénile idiopathique (AJI) est l’une des maladies chroniques auto-immune les plus répandues chez les enfants et est caractérisée par des enflures articulaires (maladie active), de la douleur, de la fatigue et des raideurs matinales pouvant restreindre leur niveau de participation aux activités quotidiennes (par exemple: les loisirs, l’activité physique, la mobilité et les soins personnels) à la maison comme à l’école. Participer aux activités de loisirs et à l’activité physique a des bienfaits au niveau de la santé et du développement de tous les enfants et démontrent aussi des effets positifs qui réduisent les symptômes des maladies chroniques telle l’AJI. Malgré ces bienfaits la participation aux loisirs chez les jeunes avec l’AJI demeure largement sous-étudiée. Objectifs: Cette étude vise à évaluer le niveau de participation aux loisirs et à l’activité physique chez les enfants et les adolescents atteints d’AJI, ainsi qu’à identifier les facteurs liés à la maladie, la personne et l’environnement. Méthodes : L’évaluation du niveau de participation et l’exploration des facteurs associés aux loisirs et à l’activité physique ont été complétés par l’entremise d’une revue systématique de la littérature, l’analyse de données d’un échantillon national représentatif d’enfants canadiens atteints d’arthrite âgés entre 5 et 14 ans (npondéré = 4350), ainsi que l’analyse standardisée du niveau de participation aux loisirs à l’aide du Children’s Assessment of Participation and Enjoyment (n=107) et la mesure objective de l’activité physique par accéléromètre (n=76) auprès d’un échantillon d’enfants (âgés entre 8 et 11 ans ) et d’adolescents (âgés entre 12 et 17 ans) suivis en clinique de rhumatologie à l’hôpital de Montréal pour enfants, Centre Universitaire de Santé McGill. Les résultats cliniques ont été comparés à des données normatives, ainsi qu’à un groupe contrôle sans AJI. Nous avons exploré les facteurs associés avec le niveau de participation aux loisirs et à l’activité physique en utilisant les modèles de régression linéaire multiple et l’analyse hiérarchique. Résultats : Les enfants et les adolescents atteints d’AJI participent à une multitude d’activités de loisirs; cependant ils sont moins souvent impliqués dans des activités physiques et de raffinement en comparaison aux autres types d’activités de loisirs. Ceux avec l’AJI étaient en général moins actifs que leurs pairs sans arthrite et la plupart n’atteignaient pas les recommandations nationales d’activité physique. Les garçons avec l’AJI participent plus souvent à des activités physiques et moins aux activités sociales, de raffinement et de développement de soi en comparaison avec les filles ayant l’AJI. En général, être un garçon, être plus âgé, avoir une meilleure motivation pour participer aux activités de motricité globale, avoir un statut socio-économique plus élevé et être d’origine culturelle canadienne sont associés à un niveau de participation plus élevé aux activités physiques. La préférence pour les activités de raffinement, un niveau d’éducation maternelle plus élevé et être une fille étaient associés à un niveau de participation plus élevé aux activités de raffinement. Conclusion: La participation aux loisirs et à l’activité physique en AJI est un concept complexe et semble surtout être expliqué par des facteurs personnels et environnementaux. L’identification des facteurs associés aux loisirs et à l’activité physique est très importante en AJI puisqu’elle peut permettre aux professionnels de la santé de développer des interventions significatives basées sur les activités préférées des enfants, améliorer l’observance au traitement et promouvoir des habitudes de vie saine.

Systematic construction of models for the exchange hole of density functional theory.

Dans ce travail, nous étendons le nombre de conditions physiques actuellement con- nues du trou d’échange exact avec la dérivation de l’expansion de quatrième ordre du trou d’échange sphérique moyenne exacte. Nous comparons les expansions de deux- ième et de quatrième ordre avec le trou d’échange exact pour des systèmes atomiques et moléculaires. Nous avons constaté que, en général, l’expansion du quatrième ordre reproduit plus fidèlement le trou d’échange exact pour les petites valeurs de la distance interélectronique. Nous démontrons que les ensembles de base de type gaussiennes ont une influence significative sur les termes de cette nouvelle condition, en étudiant com- ment les oscillations causées par ces ensembles de bases affectent son premier terme. Aussi, nous proposons quatre modèles de trous d’échange analytiques auxquels nous imposons toutes les conditions actuellement connues du trou d’échange exact et la nou- velle présentée dans ce travail. Nous évaluons la performance des modèles en calculant des énergies d’échange et ses contributions à des énergies d’atomisation. On constate que les oscillations causeés par les bases de type gaussiennes peuvent compromettre la précision et la solution des modèles.

Evidence of aging in spin glass mean-field models

We study numerically the out-of-equilibrium dynamics of the hypercubic cell spin glass in high dimensionalities. We obtain evidence of aging effects qualitatively similar both to experiments and to simulations of low-dimensional models. This suggests that the Sherrington-Kirkpatrick model as well as other mean-field finite connectivity lattices can be used to study these effects analytically.