5,824 research outputs found
Caloric vestibular stimulation in aphasic syndrome
Caloric vestibular stimulation (CVS) is commonly used to diagnose brainstem disorder but its therapeutic application is much less established. Based on the finding that CVS increases blood flow to brain structures associated with language and communication, we assessed whether the procedure has potential to relieve symptoms of post-stroke aphasia. Three participants, each presenting with chronic, unilateral lesions to the left hemisphere, were administered daily CVS for 4 consecutive weeks. Relative to their pre-treatment baseline scores, two of the three participants showed significant improvement on both picture and responsive naming at immediate and one-week follow-up. One of these participants also showed improved sentence repetition, and another showed improved auditory word discrimination. No adverse reactions were reported. These data provide the first, albeit tentative, evidence that CVS may relieve expressive and receptive symptoms of aphasia. A larger, sham-controlled study is now needed to further assess efficacy
ADOPT: a tool for predicting adoption of agricultural innovations
A wealth of evidence exists about the adoption of new practices and technologies in agriculture but there does not appear to have been any attempt to simplify this vast body of research knowledge into a model to make quantitative predictions across a broad range of contexts. This is despite increasing demand from research, development and extension agencies for estimates of likely extent of adoption and the likely timeframes for project impacts. This paper reports on the reasoning underpinning the development of ADOPT (Adoption and Diffusion Outcome Prediction Tool). The tool has been designed to: 1) predict an innovation‘s likely peak extent of adoption and likely time for reaching that peak; 2) encourage users to consider the influence of a structured set of factors affecting adoption; and 3) engage R, D & E managers and practitioners by making adoptability knowledge and considerations more transparent and understandable. The tool is structured around four aspects of adoption: 1) characteristics of the innovation, 2) characteristics of the population, 3) actual advantage of using the innovation, and 4) learning of the actual advantage of the innovation. The conceptual framework used for developing ADOPT is described.Adoption, Diffusion, Prediction, Research and Development/Tech Change/Emerging Technologies,
Extremal driving as a mechanism for generating long-term memory
It is argued that systems whose elements are renewed according to an extremal
criterion can generally be expected to exhibit long-term memory. This is
verified for the minimal extremally driven model, which is first defined and
then solved for all system sizes N\geq2 and times t\geq0, yielding exact
expressions for the persistence R(t)=[1+t/(N-1)]^{-1} and the two-time
correlation function C(t_{\rm w}+t,t_{\rm w})=(1-1/N)(N+t_{\rm w})/(N+t_{\rm
w}+t-1). The existence of long-term memory is inferred from the scaling of
C(t_{\rm w}+t,t_{\rm w})\sim f(t/t_{\rm w}), denoting {\em aging}. Finally, we
suggest ways of investigating the robustness of this mechanism when competing
processes are present.Comment: 5 pages, no figures; requires IOP style files. To appear as a J.
Phys. A. lette
Keeping the family: A socio-ecological perspective on the challenges of child removal and reunification for mothers who have experienced substance-related harms
The challenges and experiences associated with child removal and reunification from the perspective of mothers experiencing substance-related harms is under-researched in Australia. Our qualitative study employed a socio-ecological model to better understand the background to child removal, and perceived barriers and facilitators to achieving reunification of mother and child. In-depth interviews were conducted with 16 women, 8 of whom self-identified as Australian First Nations People. At the time of the interviews, these women were either living in substance use rehabilitation facilities, their own home or with relatives. Findings highlighted a history of complex disadvantage and trauma among the women, along with a deep and enduring commitment to their children. Key barriers to reunification included limited social support networks, insecure housing, and challenges in meeting conflicting requirements from the child protection, social welfare and justice systems. An important facilitator to reunification was access to a residential substance use rehabilitation facility that offered holistic wrap-around services with links to community support. This study highlights the inadequacy of individual approaches focused on parents’ substance use and emphasises the need to address significant structural disadvantages that underpin increasing numbers of children being placed in government mandated care in Australia
The Stability Challenges of Oxygen Evolving Catalysts: Towards a Common Fundamental Understanding and Mitigation of Catalyst Degradation
Manuscript submitted unter different title: "The Stability Challenges of Oxygen Evolving Electrocatalysts: Towards a Common Fundamental Understanding and Mitigation of Catalyst Degradation"This review addresses the technical challenges, their scientific basis, as well as recent progress and the road ahead with respect to the stability and degradation of OER catalysts operating at electrolyzer anodes in acidic environments with an emphasis on MEA based operation. First, we start clarifying the complexity associated with the term “catalyst stability”, cover today’s performance targets and outline major catalyst degradation mechanisms and their mitigation strategies. Then we evaluate suitable in-situ experimental methods to get insight into catalyst degradation and describe achievements in tuning OER catalyst stability. Finally, we highlight the importance of identifying universal figures of merit for stability and develop a comprehensive accelerated life test (ALT) that would yield comparable performance data across labs and catalyst types. As a whole, this review will help to disseminate and highlight the important relations between structure, composition and stability of OER catalysis under different operating conditions.DFG, 221428535, Nanostructured mixed metal oxides for the electrocatalytic oxidation of waterDFG, 198634447, SPP 1613: Regenerativ erzeugte Brennstoffe durch lichtgetriebene Wasserspaltung: Aufklärung der Elementarprozesse und Umsetzungsperspektiven auf technologische Konzept
Zinc regeneration in rechargeable zinc-air fuel cells:a review
Zinc-air fuel cells (ZAFCs) present a promising energy source with a competing potential with the lithium-ion battery and even with proton-exchange membrane fuel cells (PEMFCs) for applications in next generation electrified transport and energy storage. The regeneration of zinc is essential for developing the next-generation, i.e., electrochemically rechargeable ZAFCs. This review aims to provide a comprehensive view on both theoretical and industrial platforms already built hitherto, with focus on electrode materials, electrode and electrolyte additives, solution chemistry, zinc deposition reaction mechanisms and kinetics, and electrochemical zinc regeneration systems. The related technological challenges and their possible solutions are described and discussed. A summary of important R&D patents published within the recent 10 years is also presented
Internal alignments of red versus blue discs in dark matter haloes
Large surveys have shown that red galaxies are preferentially aligned with their haloes, while blue galaxies have a more isotropic distribution. Since haloes generally align with their filaments, this introduces a bias in the measurement of the cosmic shear from weak lensing. It is therefore vitally important to understand why this difference arises. We explore the stability of different disc orientations within triaxial haloes. We show that, in the absence of gas, the disc orientation is most stable when its spin is along the minor axis of the halo. Instead when gas cools on to a disc, it is able to form in almost arbitrary orientation, including off the main planes of the halo (but avoiding an orientation perpendicular to the halo's intermediate axis). Substructure helps gasless galaxies reach alignment with the halo faster, but has less effect on galaxies when gas is cooling on to the disc. Our results provide a novel and natural interpretation for why red, gas poor galaxies are preferentially aligned with their halo, while blue, star-forming, galaxies have nearly random orientations, without requiring a connection between galaxies' current star formation rate and their merger history
Phase Transition in the Aldous-Shields Model of Growing Trees
We study analytically the late time statistics of the number of particles in
a growing tree model introduced by Aldous and Shields. In this model, a cluster
grows in continuous time on a binary Cayley tree, starting from the root, by
absorbing new particles at the empty perimeter sites at a rate proportional to
c^{-l} where c is a positive parameter and l is the distance of the perimeter
site from the root. For c=1, this model corresponds to random binary search
trees and for c=2 it corresponds to digital search trees in computer science.
By introducing a backward Fokker-Planck approach, we calculate the mean and the
variance of the number of particles at large times and show that the variance
undergoes a `phase transition' at a critical value c=sqrt{2}. While for
c>sqrt{2} the variance is proportional to the mean and the distribution is
normal, for c<sqrt{2} the variance is anomalously large and the distribution is
non-Gaussian due to the appearance of extreme fluctuations. The model is
generalized to one where growth occurs on a tree with branches and, in this
more general case, we show that the critical point occurs at c=sqrt{m}.Comment: Latex 17 pages, 6 figure
Ergodic properties of a model for turbulent dispersion of inertial particles
We study a simple stochastic differential equation that models the dispersion
of close heavy particles moving in a turbulent flow. In one and two dimensions,
the model is closely related to the one-dimensional stationary Schroedinger
equation in a random delta-correlated potential. The ergodic properties of the
dispersion process are investigated by proving that its generator is
hypoelliptic and using control theory
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