85 research outputs found

    Chemical potential oscillations from a single nodal pocket in the underdoped high-Tc superconductor YBa2Cu3O6+x

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    The mystery of the normal state in the underdoped cuprates has deepened with the use of newer and complementary experimental probes. While photoemission studies have revealed solely `Fermi arcs' centered on nodal points in the Brillouin zone at which holes aggregate upon doping, more recent quantum oscillation experiments have been interpreted in terms of an ambipolar Fermi surface, that includes sections containing electron carriers located at the antinodal region. To address the question of whether an ambipolar Fermi surface truly exists, here we utilize measurements of the second harmonic quantum oscillations, which reveal that the amplitude of these oscillations arises mainly from oscillations in the chemical potential, providing crucial information on the nature of the Fermi surface in underdoped YBa2Cu3O6+x. In particular, the detailed relationship between the second harmonic amplitude and the fundamental amplitude of the quantum oscillations leads us to the conclusion that there exists only a single underlying quasi-two dimensional Fermi surface pocket giving rise to the multiple frequency components observed via the effects of warping, bilayer splitting and magnetic breakdown. A range of studies suggest that the pocket is most likely associated with states near the nodal region of the Brillouin zone of underdoped YBa2Cu3O6+x at high magnetic fields.Comment: 7 pages, 4 figure

    High-Field Superconductivity at an Electronic Topological Transition in URhGe

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    The emergence of superconductivity at high magnetic fields in URhGe is regarded as a paradigm for new state formation approaching a quantum critical point. Until now, a divergence of the quasiparticle mass at the metamagnetic transition was considered essential for superconductivity to survive at magnetic fields above 30 tesla. Here we report the observation of quantum oscillations in URhGe revealing a tiny pocket of heavy quasiparticles that shrinks continuously with increasing magnetic field, and finally disappears at a topological Fermi surface transition close to or at the metamagnetic field. The quasiparticle mass decreases and remains finite, implying that the Fermi velocity vanishes due to the collapse of the Fermi wavevector. This offers a novel explanation for the re-emergence of superconductivity at extreme magnetic fields and makes URhGe the first proven example of a material where magnetic field-tuning of the Fermi surface, rather than quantum criticality alone, governs quantum phase formation.Comment: A revised version has been accepted for publication in Nature Physic

    Climate change: what competencies and which medical education and training approaches?

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    <p>Abstract</p> <p>Background</p> <p>Much research has been devoted to identifying healthcare needs in a climate-changing world. However, while there are now global and national policy statements about the importance of health workforce development for climate change, little has been published about what competencies might be demanded of practitioners in a climate-changing world. In such a context, this debate and discussion paper aims to explore the nature of key competencies and related opportunities for teaching climate change in medical education and training. Particular emphasis is made on preparation for practice in rural and remote regions likely to be greatly affected by climate change.</p> <p>Discussion</p> <p>The paper describes what kinds of competencies for climate change might be included in medical education and training. It explores which curricula, teaching, learning and assessment approaches might be involved. Rather than arguing for major changes to medical education and training, this paper explores well established precedents to offer practical suggestions for where a particular kind of literacy--eco-medical literacy--and related competencies could be naturally integrated into existing elements of medical education and training.</p> <p>Summary</p> <p>The health effects of climate change have, generally, not yet been integrated into medical education and training systems. However, the necessary competencies could be taught by building on existing models, best practice and innovative traditions in medicine. Even in crowded curricula, climate change offers an opportunity to reinforce and extend understandings of how interactions between people and place affect health.</p

    Cognitive Neuropsychology of HIV-Associated Neurocognitive Disorders

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    Advances in the treatment of the human immunodeficiency virus (HIV) have dramatically improved survival rates over the past 10 years, but HIV-associated neurocognitive disorders (HAND) remain highly prevalent and continue to represent a significant public health problem. This review provides an update on the nature, extent, and diagnosis of HAND. Particular emphasis is placed on critically evaluating research within the realm of cognitive neuropsychology that aims to elucidate the component processes of HAND across the domains of executive functions, motor skills, speeded information processing, episodic memory, attention/working memory, language, and visuoperception. In addition to clarifying the cognitive mechanisms of HAND (e.g., impaired cognitive control), the cognitive neuropsychology approach may enhance the ecological validity of neuroAIDS research and inform the development of much needed novel, targeted cognitive and behavioral therapies

    Fluid Intelligence and Psychosocial Outcome: From Logical Problem Solving to Social Adaptation

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    While fluid intelligence has proved to be central to executive functioning, logical reasoning and other frontal functions, the role of this ability in psychosocial adaptation has not been well characterized.Lower fluid intelligence scores were associated with physical violence, both in the role of victim and victimizer. Drug intake, especially cannabis, cocaine and inhalants and lower self-esteem were also associated with lower fluid intelligence. Finally, scores on the perceived mental health assessment were better when fluid intelligence scores were higher.Our results show evidence of a strong association between psychosocial adaptation and fluid intelligence, suggesting that the latter is not only central to executive functioning but also forms part of a more general capacity for adaptation to social contexts

    Behavior change interventions and policies influencing primary healthcare professionals’ practice—an overview of reviews

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    Developing work-integrated learning with creative professionals in art, design and media: International students, online public profiles and sustainability

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    This chapter discusses a Professional Experience Program (PEP) conducted in an Australian university and reflects upon the importance of providing Work Integrated Learning (WIL) experiences for art, design and media students in the creative industries. The focus is specifically on developing international student experience within a larger PEP experience. Given the institutionally and academically strong background of professional experience in design studies alongside art and design education at the University of New South Wales (UNSW), Sydney: Art & Design, in existence for over 25 years, the faculty is well placed to anticipate 21st century learning goals for a suite of creative professionals. The Draft National Strategy on International Education (Department of Education and Training, 2015) forecasted that Australia needed to “expand the potential, scale and breadth of relevant work-integrated learning opportunities for international students and graduates” (p. 42). As will be argued, the Art & Design WIL experience should include developing student’s creative professional language, their professional profile and abilities to adapt and learn within a variety of locations and professional settings. It is important that art and design students are provided with supported authentic learning experiences “with an explicit emphasis on preparing (them) for the labour market in terms of knowledge and transferable skills” (Wilton, 2012, p.604). The tertiary environment should provide all students with the chance to participate in guided real-world learning opportunities that provide authentic encounters with their future professions throughout their studies with periods of longer duration during their final semester of study. Here university disciplinary knowledge and ‘real-world’ practice can combine to bring ‘real’ meaning to the learning environment. WIL provides as Dixon (2011) discussed, “a community-centric problem-based learning methodology where students address real community issues and problems” (p. 45), to prepare them for what they may face during their future roles in the workforce
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