Giant enhancement of n-type carrier mobility in highly strained germanium nanostructures

First-principles electronic structure methods are used to predict the rate of n-type carrier scattering due to phonons in highly-strained Ge. We show that strains achievable in nanoscale structures, where Ge becomes a direct bandgap semiconductor, cause the phonon-limited mobility to be enhanced by hundreds of times that of unstrained Ge, and over a thousand times that of Si. This makes highly tensile strained Ge a most promising material for the construction of channels in CMOS devices, as well as for Si-based photonic applications. Biaxial (001) strain achieves mobility enhancements of 100 to 1000 with strains over 2%. Low temperature mobility can be increased by even larger factors. Second order terms in the deformation potential of the Gamma valley are found to be important in this mobility enhancement. Although they are modified by shifts in the conduction band valleys, which are caused by carrier quantum confinement, these mobility enhancements persist in strained nanostructures down to sizes of 20 nm.

Service users experiences of a therapeutic group programme in an acute psychiatric inpatient unit.

Psychiatric nurses have been facilitating therapeutic groups in acute psychiatric inpatient units for many years; however, there is a lack of nursing research related to this important aspect of care. This paper reports the findings of a study which aimed to gain an understanding of service users' experiences in relation to therapeutic group activities in an acute inpatient unit. A qualitative descriptive study was undertaken with eight service users in one acute psychiatric inpatient unit in Ireland. Data were collected using in-depth semi-structured interviews and analysed using Burnard's method of thematic content analysis. Several themes emerged from the findings which are presented in this paper.

A first principles analysis of the effect of hydrogen concentration in hydrogenated amorphous silicon on the formation of strained Si-Si bonds and the optical and mobility gaps

In this paper, we use a model of hydrogenated amorphous silicon generated from molecular dynamics with density functional theory calculations to examine how the atomic geometry and the optical and mobility gaps are influenced by mild hydrogen oversaturation. The optical and mobility gaps show a volcano curve as the hydrogen content varies from undersaturation to mild oversaturation, with largest gaps obtained at the saturation hydrogen concentration. At the same time, mid-gap states associated with dangling bonds and strained Si-Si bonds disappear at saturation but reappear at mild oversaturation, which is consistent with the evolution of optical gap. The distribution of Si-Si bond distances provides the key to the change in electronic properties. In the undersaturation regime, the new electronic states in the gap arise from the presence of dangling bonds and strained Si-Si bonds, which are longer than the equilibrium Si-Si distance. Increasing hydrogen concentration up to saturation reduces the strained bonds and removes dangling bonds. In the case of mild oversaturation, the mid-gap states arise exclusively from an increase in the density of strained Si-Si bonds. Analysis of our structure shows that the extra hydrogen atoms form a bridge between neighbouring silicon atoms, thus increasing the Si-Si distance and increasing disorder in the sample.

A Study of the Behavioural and Affective Profile of Inpatient Adolescent Girls Presenting a Restrictive Anorexia Nervosa

Essai doctoral d'intégration présenté à la Faculté des Études Supérieures et Postdoctorales en vue de l'obtention du grade de Docteur en psychologie (D.Psy.), en psychologie clinique

'A Kind of Logic, A Kind of Dominant Logic': Navigating Colonialism, Honoring Black Mobility, and Thinking on Moving Through

My thesis thinks through the ways Newtonian logics require linear mobility in order to produce narratives of progress. I argue that this linear mobility, and the resulting logics, potentially erases the chaotic and non-linear motions that are required to navigate a colonial landscape. I suggest that these non-linear movements produce important critiques of the seeming stasis of colonial constructs and highlight the ways these logics must appear neutral and scientific in an attempt to conceal the constant and complex adjustments these frameworks require. In order to make room for these complex motions, I develop a quantum intervention. Specifically, I use quantum physics as a metaphor to think through the significance of black life, the double-consciousness ofland, and the intricate motions of sound. In order to put forth this intervention, I look at news coverage of Hurricane Katrina, Du Bois’s characterization of land in Souls of Black Folks, and the aural mobilities of blackness articulated in an academic discussion and interview about post- humanism.

Understanding arsenic mobility and speciation in lake sediments impacted by ore roasting near Giant mine, NWT

The roasting of gold-bearing arsenopyrite at Giant mine (Northwest Territories) between 1949 and 1999 released approximately 20,000 tonnes of toxic arsenic-bearing aerosols in the local aerial environment. Detailed examination of lake sediments, sediment porewaters, surface waters and lake hydrology sampled from three lakes of differing limnological characteristics was conducted in summer and winter conditions. Samples were analyzed for solid and dissolved elemental concentrations, speciation and mineralogy. The three lakes are located less than 5km from the mine roaster, and downwind, based on predominant wind direction. The objective of the study was to assess the controls on the mobility and fate of arsenic in these roaster-impacted subarctic lacustrine environments. Results show that the occurrence of arsenic trioxide in lake sediments coincides with the regional onset of industrial activities. The bulk of arsenic in sediments is contained in the form of secondary sulphide precipitates, with iron oxides hosting a minimal amount of arsenic near the surface-water interface. The presence of geogenic arsenic is likely contained as dilute impurities in common rock-forming minerals, and is not believed to be a significant source of arsenic to sediments, porewaters or lake waters. Furthermore, the well correlated depth-profiles of arsenic, antimony and gold in sediments may help reveal roaster impact. The soluble arsenic trioxide particles contained in sediments act as the primary source of arsenic into porewaters. Dissolved arsenic in reducing porewaters both precipitate as secondary sulphides in situ, and diffuse upwards into the overlying lake waters. Arsenic diffusion out of porewaters, combined with watercourse-driven residence time, are estimated to be the predominant mechanisms controlling arsenic concentrations in overlying lake waters. The sequestration of arsenic from porewaters as sulphide precipitates, in the study lakes, is not an effective process in keeping lake-water arsenic concentrations below guidelines for the protection of the freshwater environment and drinking water. Seasonal impacts on lake geochemistry derive from ice covering lake waters, cutting them off from of atmospheric oxygen, along with the exclusion of solutes from the ice. Such effects are limited in deep lakes but are can be an important factor controlling arsenic precipitation and mobility in ponds.

The Impact of Geographic Mobility on Canadian Military families and their Children’s Access Special Education Services

To achieve academic success, children with learning-related disabilities often receive special education supports at school. Currently, Canada does not have a federal department or integrated national system of education. Instead, each province and territory has a separate department or ministry that is responsible for the organization and delivery of education, including special education, at the elementary level. At the macro (national) level, inclusive education is the policy across Canada. However, each province and territory has its own legislation, definitions, and policies mandating special education services. These variations result in little consistency at the micro (individual school) level. Differences between eligibility requirements, supports offered, and delivery methods may present challenges for highly mobile families who must navigate new special education systems on behalf of their children with medical or learning challenges. One of the defining features of the Canadian military lifestyle is geographic mobility. As a result, many families are tasked with navigating new school systems for their children, a task that may be more difficult when children require special education services. The purpose of this study is to explore the impact of geographic mobility on Canadian military families and their children’s access to special education services. The secondary objective was to gain insight into supports that helped facilitate access to services, as well as supports that participants believe would have helped facilitate access. A qualitative approach, interpretive phenomenological analysis (IPA), was employed due to of its focus on individuals’ experiences and their understandings of a particular phenomenon. IPA allowed participants to reflect on the significance of their experiences, while the researcher engaged with these reflections to make sense of the meanings associated with their experiences. Nine semi-structured interviews were conducted with civilian caregivers who have a child with special education needs. An interview guide and probes were used to elicit rich, detailed, first-person accounts of their experiences navigating new special education systems. The main themes that emerged from the participants’ combined experiences addressed the emotional components of experiencing a transition, factors that may facilitate access to special education services, and career implications associated with accessing and maintaining special education services. Findings from the study illustrate that Canadian families experience many, and often times severe, barriers to accessing special education services after a posting. Furthermore, the impacts reported throughout the study echo the existing American literature on geographic mobility and access to special education services. Building on the literature, this study also highlights the need for further research exploring factors that create unique barriers to access in a Canadian context, resulting from the current special education climate, military policies, and military family support services.

The paradox of competition for airline passengers with reduced mobility (PRM)

Airline competition with customer service as product differentiator has forced down costs, air fares and investor returns. Two passenger markets operate in aviation: (a) able-bodied passengers for whom airlines compete and (b) passengers with reduced mobility (PRMs) – disabled by age, obesity or medical problems – for whom airlines do not compete. Government interference in the market intended to protect a minority of narrowly-defined PRMs has had unintended consequences of enabling increasing numbers of more widely-defined PRMs to access complimentary airline provisions. With growing ageing and overweight populations and long-haul travelling medical tourists such regulation could lead to even lower investors’ returns. The International Air Transport Association (IATA) (2013) examined the air transport value chain for competitiveness using Porter’s (2008) five forces but did not distinguish between able-bodied passengers and PRMs. Findings during an investigation of these two markets concurred with IATA-Porter that the markets for the bargaining powers of PRM buyers and PRM suppliers were highly competitive. However, in contrast to the IATA conclusions, intensity of competition, and threats from new entrants and substitute products for PRM travel were low. The conclusion is that airlines are strategically PRM defensive by omission. Paradoxically, the airline which delivers the best PRM customer service could become the least profitable.

NEIGHBORHOOD PERCEPTION OF SAFETY AND THE MOBILITY GAP BETWEEN MEN AND WOMEN IN OLD AGE

Background and Objectives: Mobility limitations are a prevalent issue in older adult populations, and an important determinant of disability and mortality. Neighborhood conditions are key determinants of mobility and perception of safety may be one such determinant. Women have more mobility limitations than men, a phenomenon known as the gender mobility gap. The objective of this work was to validate a measure of perception of safety, examine the relationship between neighborhood perception of safety and mobility limitations in seniors, and explore if these effects vary by gender. Methods: This study was cross-sectional, using questionnaire data collected from community-dwelling older adults from four sites in Canada, Colombia, and Brazil. The exposure variable was the neighborhood aggregated Perception of Safety (PoS) scale, derived from the Physical and Social Disorder (PSD) scale by Sampson and Raudenbush. Its construct validity was verified using factor analyses and correlation with similar measures. The Mobility Assessment Tool – short form (MAT-sf), a video-based measure validated cross-culturally in the studied populations, was used to assess mobility limitations. Based on theoretical models, covariates were included in the analysis, both at the neighborhood level (SES, social capital, and built environment) and the individual level (age, gender, education, income, chronic illnesses, depression, cognitive function, BMI, and social participation). Multilevel modeling was used in order to account for neighborhood clustering. Gender specific analyses were carried out. SAS and M-plus were used in this study. Results: PoS was validated across all sites. It loaded in a single factor, after excluding two items, with a Cronbach α value of approximately 0.86. Mobility limitations were present in 22.08% of the sample, 16.32% among men and 27.41% among women. Neighborhood perception of safety was significantly associated with mobility limitations when controlling for all covariates, with an OR of 0.84 (CI 95%: 0.73-0.96), indicating lower odds of having mobility limitations as neighborhood perception of safety improves. Gender did not affect this relationship despite women being more likely to have mobility limitations and live in neighborhoods with poor perception of safety. Conclusion: Neighborhood perception of safety affected the prevalence of mobility limitations in older adults in the studied population.

The paradox of competition for airline passengers with reduced mobility (PRM)

Airline competition with customer service as product differentiator has forced down costs, air fares and investor returns. Two passenger markets operate in aviation: (1) able-bodied passengers for whom airlines openly compete and (2) passengers with reduced mobility (PRMs) – disabled by age, obesity or medical problems – for whom airlines do not compete. Government interference in the market intended to protect a minority of narrowly-defined PRMs has had unintended consequences of enabling increasing numbers of more widely-defined PRMs to access complimentary airline provisions. With growing ageing and overweight populations and long-haul travelling medical tourists such regulation could lead to even lower investors’ returns. The International Air Transport Association (IATA) (2013) examined the air transport value chain for competitiveness using Porter’s (2008) five forces but did not distinguish between able-bodied passengers and PRMs. Findings during an investigation of these two markets concurred with IATA-Porter that the markets for the bargaining powers of PRM customers and PRM suppliers were ‘highly competitive’. However, in contrast to the IATA conclusions the threats posed by new entrants, substitute products and intensity of competition for PRM passengers were all ‘low’. The conclusion is that airlines are strategically PRM defensive by omission. Paradoxically, the airline which delivers the best PRM customer service could become the least profitable.

Ecuadorian migration and family strategies of social mobility: dialectic relation between emotional and financial capital

This text deals with transnational strategies of social mobility in Ecuadorian migrant households in Spain. We apply the capital accumulation model (Moser, 2009) for this purpose. The main target of this article is, beyond thinking in terms of capital stock and accumulation, the analysis in depth of the dynamics of the different types of capital, that is to say, how they interact with each other in the framework of the social mobility strategies of the migrants and their families. We are bringing into light the way some households adopt investing decisions in capitals that don't translate into any addition or earnings in all cases, on the contrary, concentrating all their efforts on the accumulation of a certain asset they may, in some cases, lead to a loss of another. We will concentrate our analysis primarily on the dynamics between the physical and financial capital and the social and emotional capital, showing the tensions produced between these two types of assets. At the same time, we will highlight how migrants negotiate their family strategies of social mobility in the transnational area. Our study is based in empirical material obtained from qualitative fieldwork (in-depth interviews) with families of migrants in the urban district of Turubamba Bajo -(south of Quito) and in Madrid. A series of households were selected where interviews were carried out in the country of origin as well as in the context of immigration, with different family members, analysing the transnational social and economic strategies of families of migrant members. Family members of migrants established in Spain were interviewed in Quito, as well as key informants in the district (school teachers, nursery members of the staff, etc.). The research was framed within the projects "Impact of migration on the development: gender and transnationalism", Ministry of Science and Innovation (SEJ2007/63179) (Laura Oso, dir. 2007-2010),"Gender, transnationalism and intergenerational strategies of social mobility", Ministry of Economy and Competitiveness (FEM2011/26210) (Laura Oso, dir. 201-1-2015) and “Gender, Crossed Mobilities and Transnational Dynamics”, Ministry of Economy and Competitiveness (FEM2015-67164).

The impact of childhood residential mobility on mental health outcomes in adolescence and early adulthood: a record linkage study.

Background Understanding the causes of poor mental health in early childhood and adolescence is important as this can be a significant determinant of mental well-being in later years. One potential and relatively unexplored factor is residential mobility in formative years. Previous studies have been relatively small and potentially limited due to methodological issues. The main aim of this study was to investigate the relationship between early residential instability and poor mental health among adolescents and young adults in Northern Ireland.

Methods A Census-based record linkage study of 28% of children aged 0–8 years in 2001 in Northern Ireland (n=49 762) was conducted, with six monthly address change assessments from health registration data and self-reported mental health status from the 2011 Census. Logistic regression models were built adjusting for socioeconomic status (SES), household composition and marital dissolution.

Results There was a graded relationship between the number of address changes and mental ill-health (adjusted OR 3.67, 95% CIs 2.11 to 6.39 for 5 or more moves). This relationship was not modified by SES or household composition. Marital dissolution was associated with poor mental health but did not modify the relationship between address change and mental health (p=0.206). There was some indication that movement after the age of five was associated with an increased likelihood of poor mental health.

Conclusions This large study clearly confirms the close relationship between address change in early years and later poor mental health. Residential mobility may be a useful marker for children at risk of poorer mental health in adolescence and early adulthood

The influence of mobility on mental health status in young people: The role of area-level deprivation

Residential mobility during childhood has been previously associated with poor mental health; however, this association could be mediated by several aspects of moving. This paper investigated the impact of mobility across different levels of area deprivation on the individual’s mental health status in Northern Ireland. Mobility towards deprived areas was associated with an elevated risk of reporting poor mental health in both house owners and renters. However, the number of residential moves appeared to be moderating the effect of area change on the individual’s mental health. Further exploration of this relationship is warranted through the use of more in-depth mental health measures