Charge confinement and Klein tunneling from doping graphene

In the present work, we investigate how structural defects in graphene can change its transport properties. In particular, we show that breaking of the sublattice symmetry in a graphene monolayer overcomes the Klein effect, leading to confined states of massless Dirac fermions. Experimentally, this corresponds to chemical bonding of foreign atoms to carbon atoms, which attach themselves to preferential positions on one of the two sublattices. In addition, we consider the scattering off a tensor barrier, which describes the rotation of the honeycomb cells of a given region around an axis perpendicular to the graphene layer. We demonstrate that in this case the intervalley mixing between the Dirac points emerges, and that Klein tunneling occurs.Comment: 11 pages, 5 figure

Mating system and population genetic structure of the bulldog ant Myrmecia pavida

Understanding the evolution of the alternative mating strategies of monandry and polyandry is a fundamental problem in evolutionary biology because of the cost-benefit trade-offs associated with mating for females. The problem is particularly intriguing in the social insects because queens in most species appear to be obligately monandrous (i.e., only a single male fathers their offspring), while those in a minority of species have evolved high, and sometimes extreme, polyandry. One group which may shed particular insight is the ant subfamily Myrmeciinae (Myrmecia and Nothomyrmecia). Here we examine the population and colony genetic structure of the bulldog ant Myrmecia pavida CLARK, 1951 by genotyping offspring workers from 45 colonies. We find little evidence of geographic structuring or inbreeding in the population, indicating that the species outbreeds, most probably in mating swarms. We also find that queens of M pavida show moderately high polyandry, with 84% having mated with between two and seven males, and an overall mean observed mating frequency of 3.8. This is significantly higher than previously reported for queens of Nothomyrmecia macrops, in which most females mate singly. This was similar to that of M pyriformis, M brevinoda, and M pilosula, the three congenerics for which mating frequencies have recently been reported. The two genera in the Myrmeciinae therefore appear to show multiple transitions in mating frequency and further investigation of the subfamily may be highly informative for disentangling the forces driving the evolution of alternative mating strategies

Identidade profissional e susceptibilidade ao Burnout em educadores sociais em formação

Este estudo investiga a relação entre as concepções associadas à Identidade Profissional e as competências pessoais que podem ser indiciadoras da susceptibilidade ao burnout em alunos de uma Licenciatura em Educação Social. São investigados 157 dos 250 alunos que frequentam o curso, distribuídos pelos 3 anos. Os resultados da análise factorial mostram a existência de factores associados à Identidade Profissional que sustentam visões antagónicas da profissão. Mostram, ainda, a existência de duas tendências de factores associados à percepção da Realização; à Explicação para os Insucessos e às Estratégias para Lidar com os Insucessos e os Sucessos indiciadoras uma de maior outra de menor susceptibilidade ao burnout. A análise de correlações entre os factores mostra ser possível estabelecer dois perfis de resposta articulando as concepções da identidade profissional com as competências pessoais subjacentes às duas tendências referidas

Implementação de programas de formação conjunto entre Instituições de Ensino Superior, Nacionais e Estrangeiras : estudo de caso do IPB

Com o presente trabalho pretende-se relatar as experiências de ‘sucesso’ desencadeadas e implementadas pelo IPB ao nível de estabelecimento de parcerias com outras Instituições de Ensino Superior (IES) para a atribuição de graus académicos conjuntos e criação de planos curriculares de 1.º e 2.º ciclos de estudos, bem como aduzir algumas dificuldades encontradas na fase de implementação desses programas de formação e discutir a possibilidade de desenvolvimento e implementação de novas parcerias com IES de Países de Língua Portuguesa e o IPB

THE PERCEPTION OF STROKE ON IADL

Background: Residents in a skilled nursing home receiving rehabilitative services following a stroke may value instrumental activity of daily living (IADL) tasks more than ADL tasks. This research investigates the impact of IADL tasks on quality of life (QoL). Purpose: The research questions were: How do individuals post-stroke and receiving occupational therapy services in a skilled nursing facility perceive their participation, or lack of participation, in IADL, and how does this impact their perceived QoL? Theoretical Framework. The theoretical framework that guided this project was the Model of Human Occupation. Methods. A phenomenological research-based qualitative approach designed to understand perceptions of stroke on QoL from lived experiences. Participants were recruited through convenient sampling, and interview questions and a Likert scale were employed. Results. Three themes: Doing things by myself, My level of confidence, and IADL tasks impact my QoL. This study revealed that participants found performance in IADL tasks meaningful despite having challenges with ADLs. They described how they valued doing things independently and would give full effort to regain function. Some participants also demonstrated self-awareness of their limitations and plans for effective discharge. Finally, all the participants expressed how IADL tasks impact their QoL. Conclusions: There was a positive connection between the performance of IADL tasks and QoL. Invariably, participants described a meaningful QoL with an increased chance of returning to IADL performance

In bloom: nurturing the liberation process of performer and character as Rose in August Wilson\u27s fences.

Rose Maxson is the 43-year-old matriarch of the Maxson household in August Wilson’s Pulitzer Prize-winning play, Fences. She is a character with an inviolable spirit. The unwavering force she possesses rattles the pages as she relives past loves, loss, experiences heartbreak. Imagine, how I, a then 24-year old devoid of the immense life experience that Rose encompasses found my way into her. The answer is through nurture. To nurture is a process of feeding, protecting, or rearing someone or something. It is a journey with or without a destination. Rose is in a constant state of nurturing her family, but how exactly does she nurture herself? My thesis will examine the approach I took to becoming Rose Maxson through a process that includes the nurturing my creative spirit and fostering of an academic mindset. I will explore these ideas through the lens of fat studies and womanism, an interdisciplinary field of study and sect of feminism developed by Alice Walker

The inter-outburst behavior of cataclysmic variables

Existing International Ultraviolet Explorer (IUE) and American Association of Variable Star Observers (AAVSO) archive data was used to accomplish a large scale study of what happens to the ultraviolet flux of accretion disk systems during the quiescent intervals between outbursts and how it relates to the preceding outburst characteristics of amplitude and width. The data sample involved multiple IUE observations for 16 dwarf novae and 8 novae along with existing optical coverage. Results indicate that most systems show correlated ultraviolet (UV) flux behavior with interoutburst phase, with 60 percent of the dwarf novae and 50 percent of the novae having decreasing flux trends while 33 percent of the dwarf novae and 38 percent of the novae show rising UV flux during the quiescent interval. All of the dwarf novae with decreasing UV fluxes at 1475A have orbital periods longer than 4.4 hours, while all (except BV Cen) with flat or rising fluxes at 1475A have orbital periods less than two hours. There are not widespread correlations of the UV fluxes with the amplitude of the preceding outburst and no correlations with the width of the outburst. From a small sample (7) that have relatively large quiescent V magnitude changes between the IUE observations, most show a strong correlation between the UV and optical continuum. Interpretation of the results is complicated by not being able to determine how much the white dwarf contributes to the ultraviolet flux. However, it is now evident that noticeable changes are occurring in the hot zones in accreting systems long after the outburst, and not only for systems that are dominated by the white dwarf. Whether these differences are due to different outburst mechanisms or to changes on white dwarfs which provide varying contributions to the UV flux remains to be determined