155 research outputs found

    Microscopic Theory for Coupled Atomistic Magnetization and Lattice Dynamics

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    A coupled atomistic spin and lattice dynamics approach is developed which merges the dynamics of these two degrees of freedom into a single set of coupled equations of motion. The underlying microscopic model comprises local exchange interactions between the electron spin and magnetic moment and the local couplings between the electronic charge and lattice displacements. An effective action for the spin and lattice variables is constructed in which the interactions among the spin and lattice components are determined by the underlying electronic structure. In this way, expressions are obtained for the electronically mediated couplings between the spin and lattice degrees of freedom, besides the well known inter-atomic force constants and spin-spin interactions. These former susceptibilities provide an atomistic ab initio description for the coupled spin and lattice dynamics. It is important to notice that this theory is strictly bilinear in the spin and lattice variables and provides a minimal model for the coupled dynamics of these subsystems and that the two subsystems are treated on the same footing. Questions concerning time-reversal and inversion symmetry are rigorously addressed and it is shown how these aspects are absorbed in the tensor structure of the interaction fields. By means of these results regarding the spin-lattice coupling, simple explanations of ionic dimerization in double anti-ferromagnetic materials, as well as, charge density waves induced by a non-uniform spin structure are given. In the final parts, a set of coupled equations of motion for the combined spin and lattice dynamics are constructed, which subsequently can be reduced to a form which is analogous to the Landau-Lifshitz-Gilbert equations for spin dynamics and damped driven mechanical oscillator for the ...Comment: 22 pages, including 7 pages of Appendix and references, 6 figure

    Measurement of Photon Statistics with Live Photoreceptor Cells

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    We analyzed the electrophysiological response of an isolated rod photoreceptor of Xenopus laevis under stimulation by coherent and pseudo-thermal light sources. Using the suction electrode technique for single cell recordings and a fiber optics setup for light delivery allowed measurements of the major statistical characteristics of the rod response. The results indicate differences in average responses of rod cells to coherent and pseudo-thermal light of the same intensity and also differences in signal-to-noise ratios and second order intensity correlation functions. These findings should be relevant for interdisciplinary studies seeking applications of quantum optics in biology.Comment: 6 pages, 7 figure

    Decolonising qualitative research with respectful, reciprocal, and responsible research practice: A narrative review of the application of Yarning method in qualitative Aboriginal and Torres Strait Islander health research

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    Background Indigenous academics have advocated for the use and validity of Indigenous methodologies and methods to centre Indigenous ways of knowing, being and doing in research. Yarning is the most reported Indigenous method used in Aboriginal and Torres Strait Islander qualitative health research. Despite this, there has been no critical analysis of how Yarning methods are applied to research conduct and particularly how they privilege Indigenous peoples. Objective To investigate how researchers are applying Yarning method to health research and examine the role of Aboriginal and Torres Strait Islander researchers in the Yarning process as reported in health publications. Design Narrative review of qualitative studies. Data sources Lowitja Institute LitSearch January 2008 to December 2021 to access all literature reporting on Aboriginal and Torres Strait Islander health research in the PubMed database. A subset of extracted data was used for this review to focus on qualitative publications that reported using Yarning methods. Methods Thematic analysis was conducted using hybrid of inductive and deductive coding. Initial analysis involved independent coding by two authors, with checking by a third member. Once codes were developed and agreed, the remaining publications were coded and checked by a third team member. Results Forty-six publications were included for review. Yarning was considered a culturally safe data collection process that privileges Indigenous knowledge systems. Details of the Yarning processes and team positioning were vague. Some publications offered a more comprehensive description of the research team, positioning and demonstrated reflexive practice. Training and experience in both qualitative and Indigenous methods were often not reported. Only 11 publications reported being Aboriginal and/or Torres Strait Islander led. Half the publications reported Aboriginal and Torres Strait Islander involvement in data collection, and 24 reported involvement in analysis. Details regarding the role and involvement of study reference or advisory groups were limited. Conclusion Aboriginal and Torres Strait Islander people should be at the forefront of Indigenous research. While Yarning method has been identified as a legitimate research method to decolonising research practice, it must be followed and reported accurately. Researcher reflexivity and positioning, and Aboriginal and Torres Strait Islander ownership, stewardship and custodianship of data collected were significantly under detailed in the publications included in our review. Journals and other establishments should review their processes to ensure necessary details are reported in publications and engage Indigenous Editors and peer reviewers to uphold respectful, reciprocal, responsible and ethical research practice

    Factors contributing to delayed diagnosis of cancer among Aboriginal people in Australia: a qualitative study.

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    BACKGROUND/OBJECTIVES: Delayed presentation of symptomatic cancer is associated with poorer survival. Aboriginal patients with cancer have higher rates of distant metastases at diagnosis compared with non-Aboriginal Australians. This paper examined factors contributing to delayed diagnosis of cancer among Aboriginal Australians from patient and service providers' perspectives. METHODS: In-depth, open-ended interviews were conducted in two stages (2006-2007 and 2011). Inductive thematic analysis was assisted by use of NVivo looking around delays in presentation, diagnosis and referral for cancer. PARTICIPANTS: Aboriginal patients with cancer/family members (n=30) and health service providers (n=62) were recruited from metropolitan Perth and six rural/remote regions of Western Australia. RESULTS: Three broad themes of factors were identified: (1) Contextual factors such as intergenerational impact of colonisation and racism and socioeconomic deprivation have negatively impacted on Aboriginal Australians' trust of the healthcare professionals; (2) health service-related factors included low accessibility to health services, long waiting periods, inadequate numbers of Aboriginal professionals and high staff turnover; (3) patient appraisal of symptoms and decision-making, fear of cancer and denial of symptoms were key reasons patients procrastinated in seeking help. Elements of shame, embarrassment, shyness of seeing the doctor, psychological 'fear of the whole health system', attachment to the land and 'fear of leaving home' for cancer treatment in metropolitan cities were other deterrents for Aboriginal people. Manifestation of masculinity and the belief that 'health is women's domain' emerged as a reason why Aboriginal men were reluctant to receive health checks. CONCLUSIONS: Solutions to improved Aboriginal cancer outcomes include focusing on the primary care sector encouraging general practitioners to be proactive to suspicion of symptoms with appropriate investigations to facilitate earlier diagnosis and the need to improve Aboriginal health literacy regarding cancer. Access to health services remains a critical problem affecting timely diagnosis

    Aboriginal Practitioners Speak Out: Contextualising Child Protection Interventions

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    One month before the June 2007 Federal Government Emergency Intervention in the Northern Territory some 55 West Australian Aboriginal child protection workers attended a 3-day summit in Fremantle. Their purpose as front-line practitioners from across the State was to identify how more nurturing and healing communities could be developed and supported in a climate of despair. This paper reports on how the summit was designed and on some of the ideas and concerns that emerged within this dialogical space of cooperative inquiry. The project was a partnership between Aboriginal and non-Aboriginal representatives of university, government, and community-service bodies. Aboriginal practitioners identified the complexity of what was happening in their experience and where changes were needed. Integral to this participation and coproduction of knowledge by Aboriginal child protection workers was the provision of a safe space for the articulation of reflected experience. Implications for policy, practice, and curriculum of both process and outcome dimensions to considering Aboriginal views on this contentious issue are discussed

    Living with rheumatic heart disease at the intersection of biomedical and Aboriginal worldviews

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    Rheumatic heart disease (RHD) significantly impacts the lives of First Nations Australians. Failure to eliminate RHD is in part attributed to healthcare strategies that fail to understand the lived experience of RHD. To rectify this, a PhD study was undertaken in the Northern Territory (NT) of Australia, combining Aboriginal ways of knowing, being and doing with interviews (24 participants from clinical and community settings) and participant observation to privilege Aboriginal voices, including the interpretations and experiences of Aboriginal co-researchers (described in the adjunct article). During analysis, Aboriginal co-researchers identified three interwoven themes: maintaining good feelings; creating clear understanding (from good information); and choosing a good djalkiri (path). These affirm a worldview that prioritises relationships, positive emotions and the wellbeing of family/community. The findings demonstrate the inter-connectedness of knowledge, choice and behaviour that become increasingly complex in stressful and traumatic health, socioeconomic, political, historical and cultural contexts. Not previously heard in the RHD domain, the findings reveal fundamental differences between Aboriginal and biomedical worldviews contributing to the failure of current approaches to communicating health messages. Mitigating this, Aboriginal co-researchers provided targeted recommendations for culturally responsive health encounters, including: communicating to create positive emotions; building trust; and providing family and community data and health messages (rather than individualistic)

    Laying the foundations of community engagement in Aboriginal health research: establishing a community reference group and terms of reference in a novel research field

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    Background Community engagement or community involvement in Aboriginal health research is a process that involves partnering, collaborating and involving Aboriginal and Torres Strait Islander people or potential research participants to empower them to have a say in how research with Aboriginal communities is conducted. In the context of Aboriginal health, this is particularly important so that researchers can respond to the priorities of the community under study and conduct research in a way that is respectful of Aboriginal cultural values and beliefs. One approach to incorporating the principals of community engagement and to ensure cultural oversight and guidance to projects is to engage a community reference group. The aim of this study was to describe the process of establishing an Aboriginal community reference group and terms of reference. The community reference group was established to guide the research activities of a newly formed research collaboration aiming to to develop osteoarthritis care that meets the needs of Aboriginal and Torres Strait Islander people in Australia. Methods Adopting a Participatory Action Research approach, this two-phase study was conducted in Victoria, Australia. In phase one, semi-structured research yarns (a cultural form of conversation used as a data gathering tool) were conducted collaboratively by Aboriginal and non-Aboriginal co-investigators to explore Aboriginal health stakeholder perspectives on establishing a community reference group and terms of reference. In phase two, recommendations in phase one were identified to invite members to participate in the community reference group and to ratify the terms of reference through a focus group. Data were analyzed using a framework analysis approach. Results Thirteen people (eight female, four male) participated in phase one. Participants represented diverse professional backgrounds including physiotherapy, nursing, general practice, health services management, hospital liaison, cultural safety education, health research and the arts. Three themes were identified in phase one; Recruitment and Representation (trust and relationships, in-house call-outs, broad-spectrum expertise and Aboriginal majority); Purpose (community engagement, research steering, knowledge dissemination and advocacy) and; Function and Logistics (frequency and format of meetings, size of group, roles and responsibilities, authority, communication and dissemination). In phase two, six Aboriginal people were invited to become members of the community reference group who recommended changes which were incorporated into the seven domains of the terms of reference. Conclusion The findings of this study are captured in a 10-step framework which describes practical strategies for establishing a community reference group and terms of reference in Aboriginal health research

    Understanding the impact and tackling the burden of osteoarthritis for Aboriginal and Torres Strait Islander people

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    Objective The aim of this study was to understand and describe the lived experience of Aboriginal and Torres Strait Islander people with osteoarthritis. Methods Qualitative study guided by cultural security, which ensures that research is conducted in a way that will not compromise the cultural values, beliefs, and expectations of Aboriginal and Torres Strait Islander people. Participants were purposively sampled through the networks of project staff. Research yarns (a cultural form of conversation used as a data gathering tool) were conducted with 25 Aboriginal and Torres Strait Islander adults with self-reported osteoarthritis in Western Australia and Victoria, Australia. Data were analyzed using a framework approach and presented through composite storytelling (hypothetical stories representing an amalgam of participants’ experiences). Results Two composite stories were constructed to reflect themes relating to beliefs and knowledge, impact, coping, and health care experiences. Common beliefs held by participants were that osteoarthritis is caused by previous physically active lifestyles. Many participants feared for their future, increasing disability and needing a wheelchair. Pain associated with osteoarthritis impacted daily activities, sleep, work, family, and social life and cultural activities. Multidimensional impacts were often experienced within complex health or life circumstances and associated with increased anxiety and depression. Most participants reported negative health care experiences, characterized by poor patient–provider communication. Conclusion Our findings highlight that osteoarthritis is a multidimensional issue for Aboriginal and Torres Strait Islander people that permeates all aspects of life and highlights the need for integrated, multidisciplinary care that is culturally informed and individualized to patient need

    Let's CHAT (community health approaches to) dementia in Aboriginal and Torres Strait Islander communities: protocol for a stepped wedge cluster randomised controlled trial

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    Background: Documented rates of dementia and cognitive impairment not dementia (CIND) in older Aboriginal and Torres Strait Islander Peoples is 3–5 times higher than the rest of the population, and current evidence suggests this condition is under-diagnosed and under-managed in a clinical primary care setting. This study aims to implement and evaluate a culturally responsive best practice model of care to optimise the detection and management of people with cognitive impairment and/or dementia, and to improve the quality of life of carers and older Aboriginal and Torres Islander Peoples with cognitive impairment. Methods/design: The prospective study will use a stepped-wedge cluster randomised controlled trial design working with 12 Aboriginal Community Controlled Health Services (ACCHSs) across four states of Australia. Utilising a co-design approach, health system adaptations will be implemented including (i) development of a best practice guide for cognitive impairment and dementia in Aboriginal and Torres Strait Islander communities (ii) education programs for health professionals supported by local champions and (iii) development of decision support systems for local medical software. In addition, the study will utilise a knowledge translation framework, the Integrated Promoting Action on Research Implementation in Health Services (iPARIHS) Framework, to promote long-term sustainable practice change. Process evaluation will also be undertaken to measure the quality, fidelity and contextual influences on the outcomes of the implementation. The primary outcome measures will be rates of documentation of dementia and CIND, and evidence of improved management of dementia and CIND among older Indigenous peoples attending Aboriginal and Torres Strait Islander primary care services through health system changes. The secondary outcomes will be improvements to the quality of life of older Indigenous peoples with dementia and CIND, as well as that of their carers and families. Discussion: The Let’s CHAT Dementia project will co-design, implement and evaluate a culturally responsive best practice model of care embedded within current Indigenous primary health care. The best practice model of care has the potential to optimise the timely detection (especially in the early stages) and improve the ongoing management of people with dementia or cognitive impairmentKate Bradley, Robyn Smith, Jo-anne Hughson, David Atkinson, Dawn Bessarab, Leon Flicker ... et al

    Theory of noncollinear interactions beyond Heisenberg exchange: Applications to bcc Fe

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    We show for a simple noncollinear configuration of the atomistic spins (in particular, where one spin is rotated by a finite angle in a ferromagnetic background) that the pairwise energy variation computed in terms of multiple-scattering formalism cannot be fully mapped onto a bilinear Heisenberg spin model even in the absence of spin-orbit coupling. The non-Heisenberg terms induced by the spin-polarized host appear in leading orders in the expansion of the infinitesimal angle variations. However, an E g − T 2 g symmetry analysis based on the orbital decomposition of the exchange parameters in bcc Fe leads to the conclusion that the nearest-neighbor exchange parameters related to the T 2 g orbitals are essentially Heisenberg-like: they do not depend on the spin configuration, and can, in this case, be mapped onto a Heisenberg spin model even in extreme noncollinear cases.Supports from the Swedish Research Council (VR), the KAW foundation (grants 2012.0031 and 2013.0020) and eSSENCE are acknowledged.The computations were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC). A. Bergman acknowledges support from CEA-Enhanced Eurotalents, co-funded by FP7 Marie Sk lodowska-Curie COFUND Programme (Grant Agreement n 600382). P. F. Bessarab acknowledges support from the Icelandic Research Fund (Grant No. 163048-052) and the mega-grant of the Ministry of Education and Science of the Russian Federation (grant no. 14.Y26.31.0015). R. Cardias, D. C. M. Rodrigues, and A. B. Klautau acknowledge financial support from CAPES and CNPq, Brazil.Peer Reviewe
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