1,669 research outputs found
Persistent fluctuations in stride intervals under fractal auditory stimulation
Copyright @ 2014 Marmelat et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Stride sequences of healthy gait are characterized by persistent long-range correlations, which become anti-persistent in the presence of an isochronous metronome. The latter phenomenon is of particular interest because auditory cueing is generally considered to reduce stride variability and may hence be beneficial for stabilizing gait. Complex systems tend to match their correlation structure when synchronizing. In gait training, can one capitalize on this tendency by using a fractal metronome rather than an isochronous one? We examined whether auditory cues with fractal variations in inter-beat intervals yield similar fractal inter-stride interval variability as isochronous auditory cueing in two complementary experiments. In Experiment 1, participants walked on a treadmill while being paced by either an isochronous or a fractal metronome with different variation strengths between beats in order to test whether participants managed to synchronize with a fractal metronome and to determine the necessary amount of variability for participants to switch from anti-persistent to persistent inter-stride intervals. Participants did synchronize with the metronome despite its fractal randomness. The corresponding coefficient of variation of inter-beat intervals was fixed in Experiment 2, in which participants walked on a treadmill while being paced by non-isochronous metronomes with different scaling exponents. As expected, inter-stride intervals showed persistent correlations similar to self-paced walking only when cueing contained persistent correlations. Our results open up a new window to optimize rhythmic auditory cueing for gait stabilization by integrating fractal fluctuations in the inter-beat intervals.Commission of the European Community and the Netherlands Organisation for Scientific Research
Structural plasticity of the living kinetochore
The kinetochore is a large, evolutionarily conserved protein structure that connects chromosomes with microtubules. During chromosome segregation, outer kinetochore components track depolymerizing ends of microtubules to facilitate the separation of chromosomes into two cells. In budding yeast, each chromosome has a point centromere upon which a single kinetochore is built, which attaches to a single microtubule. This defined architecture facilitates quantitative examination of kinetochores during the cell cycle. Using three independent measures-calibrated imaging, FRAP, and photoconversion-we find that the Dam1 submodule is unchanged during anaphase, whereas MIND and Ndc80 submodules add copies to form an "anaphase configuration" kinetochore. Microtubule depolymerization and kinesin-related motors contribute to copy addition. Mathematical simulations indicate that the addition of microtubule attachments could facilitate tracking during rapid microtubule depolymerization. We speculate that the minimal kinetochore configuration, which exists from G1 through metaphase, allows for correction of misattachments. Our study provides insight into dynamics and plasticity of the kinetochore structure during chromosome segregation in living cells
Microwave and terahertz dielectric properties of MgTiO3–CaTiO3 ceramics
The THz dielectric properties of MgTiO3–CaTiO3 ceramics are reported. The ceramics were prepared via a solid-state reaction route and the sintering conditions were optimized to obtain ceramics with high permittivity and low loss in the terahertz frequency domain. The amount of impurities (MgTi2O5) and grain size increased with increasing sintering temperature. The dielectric properties improved with increasing density, and the best terahertz dielectric performance was obtained at 1260 °C, with a permittivity of 17.73 and loss of 3.07×10−3. Ceramics sintered above 1260 °C showed a sharp increase in loss, which is ascribed to an increase in the impurity content
Quantifying the relative contributions of habitat modification and mammalian predators on landscape-scale declines of a threatened river specialist duck
Habitat modification and introduced mammalian predators are linked to global species extinctions and declines, but their relative influences can be uncertain, often making conservation management difficult. Using landscape-scale models, we quantified the relative impacts of habitat modification and mammalian predation on the range contraction of a threatened New Zealand riverine duck. We combined 38 years of whio (Hymenolaimus malacorhynchos) observations with national-scale environmental data to predict relative likelihood of occurrence (RLO) under two scenarios using bootstrapped boosted regression trees (BRT). Our models used training data from contemporary environments to predict the potential contemporary whio distribution across New Zealand riverscapes in the absence of introduced mammalian predators. Then, using estimates of environments prior to human arrival, we used the same models to hindcast potential pre-human whio distribution prior to widespread land clearance. Comparing RLO differences between potential pre-human, potential contemporary and observed contemporary distributions allowed us to assess the relative impacts of the two main drivers of decline; habitat modification and mammalian predation. Whio have undergone widespread catastrophic declines most likely linked to mammalian predation, with smaller declines due to habitat modification (range contractions of 95% and 37%, respectively). We also identified areas of potential contemporary habitat outside their current range that would be suitable for whio conservation if mammalian predator control could be implemented. Our approach presents a practical technique for estimating the relative importance of global change drivers in species declines and extinctions, as well as providing valuable information to improve conservation planning
Implementation frameworks for polypharmacy management within healthcare organisations: a scoping review.
Several guidelines support polypharmacy management in individual patients. More organisational-level focus is needed on the use of implementation frameworks. The aim of this scoping review was to characterise the peer-reviewed literature on implementation frameworks, focussing on barriers and facilitators to implementation at organisational level in the context of polypharmacy management. A scoping review protocol was devised, supporting retrieval of studies published in English, reporting from any sector of practice. Medline, International Pharmaceutical Abstracts, Cumulative Index of Nursing and Allied Health Literature and Business Source Complete were searched to January 2022 using Medical Subject Headings including: 'polypharmacy', 'deprescriptions', 'strategic planning' and 'organizational innovation'. A narrative approach to data synthesis was applied. Searching, data extraction and synthesis were undertaken independently by two reviewers. After screening 797 records, eight papers remained. Two were descriptive, outlining details of specific initiatives; six used qualitative methods to explore determinants for implementation, including barriers and enablers. Barriers at the organisation level included: poor organisational culture with a lack of sense of urgency and national plans, resource availability and communication issues including patient information and at transitions of care. Organisational facilitators included availability of government funding and regulatory environment promoting patient safety, a national emphasis on quality of care for older adults, co-ordinated national efforts and local evidence. Limited literature focusses on the use of implementation frameworks at organisational levels. This review highlights the need for further work on implementation frameworks in this context to help achieve effective organisational change
A qualitative exploration of key stakeholders’ views and perceptions in relation to organisational change for the implementation of polypharmacy management in Oman.
Polypharmacy contributes to patient non-adherence and increases medication harm. Barriers to implementation prevent desired outcomes when addressing inappropriate polypharmacy at organisational levels and there is a need for theory-based strategies for change management. The objective of this study was to explore the views and perceptions of key stakeholders in relation to organisational change for the development and implementation of a polypharmacy management healthcare strategy in Oman. Qualitative face to face interviews started in March 2022 with key stakeholders in Oman Ministry of Health (MOH) including leaders from practice of Medical, pharmacy and nursing as well as academic leaders from school of medicine, pharmacy and nursing. The interview schedule developed based on a scoping review, Kotter's first three steps of leading change and grounded in the consolidated Framework for Implementation Research (CIFR). Interviews were digitally recorded, transcribed, and analysed independently by at least two researchers using CFIR as a coding framework. Ethics approval was in place prior to data generation. Identified themes related to views and perceptions of key stakeholders in relation to the topic area. To date, ten interviews have been conducted with directors of medical (n=2), pharmacy (2) and nursing practice (1), academic healthcare leaders (3), a healthcare policy developer (1) and patient safety leader (1). Additional interviews are planned and will continue until data saturation. Emerging themes show that participants have views that polypharmacy is a burden on healthcare services and there is a need for organisational change in relation to polypharmacy management. Perceptions of reported organisational level barriers were; fragmentation of care, lack of systems for coordination among healthcare providers, absence of electronic link between the government and private sector, lack of sense of urgency among leaders regarding the polypharmacy and shortage of pharmacists. Facilitators were; the presence of well-developed electronic health system and leadership support. There is a need for for organisational change in relation to polypharmacy management in Oman. Further research is needed to obtain consensus of Omani stakeholders on the plan for a strategic framework for organisational change in relation to polypharmacy management
Poly(ethylene-<em>co</em>-butylene) functionalized multi walled carbon nanotubes applied in polypropylene nanocomposites
The functions and consequences of force at kinetochores
Chromosome segregation requires the generation of force at the kinetochore—the multiprotein structure that facilitates attachment of chromosomes to spindle microtubules. This force is required both to move chromosomes and to signal the formation of proper bioriented attachments. To understand the role of force in these processes, it is critical to define how force is generated at kinetochores, the contributions of this force to chromosome movement, and how the kinetochore is structured and organized to withstand and respond to force. Classical studies and recent work provide a framework to dissect the mechanisms, functions, and consequences of force at kinetochores.National Institute of General Medical Sciences (U.S.) (Grant GM088313
Bioelectromagnetics research within an Australian context: the Australian centre for electromagnetic bioeffects research (ACEBR)
Mobile phone subscriptions continue to increase across the world, with the electromagnetic fields (EMF) emitted by these devices, as well as by related technologies such as Wi-Fi and smart meters, now ubiquitous. This increase in use and consequent exposure to mobile communication (MC)-related EMF has led to concern about possible health effects that could arise from this exposure. Although much research has been conducted since the introduction of these technologies, uncertainty about the impact on health remains. The Australian Centre for Electromagnetic Bioeffects Research (ACEBR) is a National Health and Medical Research Council Centre of Research Excellence that is undertaking research addressing the most important aspects of the MC-EMF health debate, with a strong focus on mechanisms, neurodegenerative diseases, cancer, and exposure dosimetry. This research takes as its starting point the current scientific status quo, but also addresses the adequacy of the evidence for the status quo. Risk communication research complements the above, and aims to ensure that whatever is found, it is communicated effectively and appropriately. This paper provides a summary of this ACEBR research (both completed and ongoing), and discusses the rationale for conducting it in light of the prevailing science.Sarah P. Loughran ... Jim Manavis ... Robert Vink ... et al
Do we have any solid evidence of clinical utility about the pathophysiology of schizophrenia?
A diagnosis of schizophrenia, as in most of psychiatric practice, is made largely by eliciting symptoms with reference to subjective, albeit operationalized, criteria. This diagnosis then provides some rationale for management. Objective diagnostic and therapeutic tests are much more desirable, provided they are reliably measured and interpreted. Definite advances have been made in our understanding of schizophrenia in recent decades, but there has been little consideration of how this information could be used in clinical practice. We review here the potential utility of the strongest and best replicated risk factors for and manifestations of schizophrenia within clinical, epidemiological, cognitive, blood biomarker and neuroimaging domains. We place particular emphasis on the sensitivity, specificity and predictive power of pathophysiological indices for making a diagnosis, establishing an early diagnosis or predicting treatment response in schizophrenia. We conclude that a number of measures currently available have the potential to increase the rigour of clinical assessments in schizophrenia. We propose that the time has come to more fully evaluate these and other well replicated abnormalities as objective potential diagnostic and prognostic guides, and to steer future clinical, therapeutic and nosological research in this direction
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