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Search Results: 1 - 10 of 139201 matches for " K. Warner Schaie "
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Social Activity and Cognitive Functioning Over Time: A Coordinated Analysis of Four Longitudinal Studies
Cassandra L. Brown,Laura E. Gibbons,Robert F. Kennison,Annie Robitaille,Magnus Lindwall,Meghan B. Mitchell,Steven D. Shirk,Alireza Atri,Cynthia R. Cimino,Andreana Benitez,Stuart W. S. MacDonald,Elizabeth M. Zelinski,Sherry L. Willis,K. Warner Schaie,Boo Johansson,Roger A. Dixon,Dan M. Mungas,Scott M. Hofer,Andrea M. Piccinin
Journal of Aging Research , 2012, DOI: 10.1155/2012/287438
Abstract: Social activity is typically viewed as part of an engaged lifestyle that may help mitigate the deleterious effects of advanced age on cognitive function. As such, social activity has been examined in relation to cognitive abilities later in life. However, longitudinal evidence for this hypothesis thus far remains inconclusive. The current study sought to clarify the relationship between social activity and cognitive function over time using a coordinated data analysis approach across four longitudinal studies. A series of multilevel growth models with social activity included as a covariate is presented. Four domains of cognitive function were assessed: reasoning, memory, fluency, and semantic knowledge. Results suggest that baseline social activity is related to some, but not all, cognitive functions. Baseline social activity levels failed to predict rate of decline in most cognitive abilities. Changes in social activity were not consistently associated with cognitive functioning. Our findings do not provide consistent evidence that changes in social activity correspond to immediate benefits in cognitive functioning, except perhaps for verbal fluency. 1. Introduction Cognitive decline in older adulthood remains an area of great concern as the population ages. Some changes in cognitive function, such as decreased processing speed, are considered normative aspects of the aging process [1]. However, the impact of even mild cognitive impairment on functional capacity highlights the importance of maintaining cognitive function for as long as possible [2]. Substantial evidence suggests that lifestyle factors and cognitive function in older adulthood are related [3]. Sometimes summarized by the adage “use it or lose it,” current evidence suggests that leading an active lifestyle “using it” may buffer the effects of age-related cognitive decline “losing it” [3–5]. The mechanisms by which an active and engaged lifestyle may be related to better or preserved cognitive function in older adulthood remain to be fully elucidated. However, the cognitive reserve hypothesis predicts that some individuals are better able to withstand the physiological insults to the brain without measurable cognitive deficits because they had greater capacity to begin with [6]. Individuals may be able to actively increase their “reserve” through engaging in cognitively stimulating activities [3]. Social activities are considered part of what constitutes an active and engaged lifestyle, alongside cognitive and physical activities [3, 4, 7–9]. However, the evidence for a relationship
Cognitively Stimulating Activities: Effects on Cognition across Four Studies with up to 21 Years of Longitudinal Data
Meghan B. Mitchell,Cynthia R. Cimino,Andreana Benitez,Cassandra L. Brown,Laura E. Gibbons,Robert F. Kennison,Steven D. Shirk,Alireza Atri,Annie Robitaille,Stuart W. S. MacDonald,Magnus Lindwall,Elizabeth M. Zelinski,Sherry L. Willis,K. Warner Schaie,Boo Johansson,Roger A. Dixon,Dan M. Mungas,Scott M. Hofer,Andrea M. Piccinin
Journal of Aging Research , 2012, DOI: 10.1155/2012/461592
Abstract: Engagement in cognitively stimulating activities has been considered to maintain or strengthen cognitive skills, thereby minimizing age-related cognitive decline. While the idea that there may be a modifiable behavior that could lower risk for cognitive decline is appealing and potentially empowering for older adults, research findings have not consistently supported the beneficial effects of engaging in cognitively stimulating tasks. Using observational studies of naturalistic cognitive activities, we report a series of mixed effects models that include baseline and change in cognitive activity predicting cognitive outcomes over up to 21 years in four longitudinal studies of aging. Consistent evidence was found for cross-sectional relationships between level of cognitive activity and cognitive test performance. Baseline activity at an earlier age did not, however, predict rate of decline later in life, thus not supporting the concept that engaging in cognitive activity at an earlier point in time increases one's ability to mitigate future age-related cognitive decline. In contrast, change in activity was associated with relative change in cognitive performance. Results therefore suggest that change in cognitive activity from one's previous level has at least a transitory association with cognitive performance measured at the same point in time. 1. Introduction With the rising proportion of older adults and increases in life expectancy [1], there has been increased interest in maintaining and promoting cognitive health in later life. Although declines in some domains of cognition are part of the natural course of aging [2, 3], sufficient evidence from prospective and observational studies indicates that the trajectories and outcomes of cognitive decline may be mitigated by participating in cognitively stimulating activities [4, 5]. Recent reviews of cognitive interventions suggest some potential benefits that may improve functioning in healthy older adults or slow decline in individuals with mild cognitive impairment (MCI) and those already affected with dementia [6–9]. Results from a meta-analysis of randomized controlled trials in healthy aging revealed a strong positive effect on cognition at immediate, medium-, and long-term followup after cognitive training [10]. Compelling results from large longitudinal studies have also shown that engagement in everyday cognitive activities predicts preserved cognition [11, 12] and decreases in incident Alzheimer’s disease [13]. It is therefore not surprising that the market for “brain fitness” technologies,
Dynamic Associations of Change in Physical Activity and Change in Cognitive Function: Coordinated Analyses of Four Longitudinal Studies
Magnus Lindwall,Cynthia R. Cimino,Laura E. Gibbons,Meghan B. Mitchell,Andreana Benitez,Cassandra L. Brown,Robert F. Kennison,Steven D. Shirk,Alireza Atri,Annie Robitaille,Stuart W. S. MacDonald,Elizabeth M. Zelinski,Sherry L. Willis,K. Warner Schaie,Boo Johansson,Marcus Praetorius,Roger A. Dixon,Dan M. Mungas,Scott M. Hofer,Andrea M. Piccinin
Journal of Aging Research , 2012, DOI: 10.1155/2012/493598
Abstract: The present study used a coordinated analyses approach to examine the association of physical activity and cognitive change in four longitudinal studies. A series of multilevel growth models with physical activity included both as a fixed (between-person) and time-varying (within-person) predictor of four domains of cognitive function (reasoning, memory, fluency, and semantic knowledge) was used. Baseline physical activity predicted fluency, reasoning and memory in two studies. However, there was a consistent pattern of positive relationships between time-specific changes in physical activity and time-specific changes in cognition, controlling for expected linear trajectories over time, across all four studies. This pattern was most evident for the domains of reasoning and fluency. 1. Introduction Previous research has clearly demonstrated that cognitive change in old age does not occur in a homogenous manner for all individuals [1–3]. A number of predictors of cognitive change in old age have been identified, such as education, hypertension, objective indices of health and cardiovascular disease, and apolipoprotein E [4]. Regular engagement in different types of activities may also influence cognitive change. More specifically, according to the “use it or lose it” hypothesis [5], regular engagement in different activities may buffer age-related decline in cognitive functioning. A number of studies have found that general lifestyle activity engagement (often operationalized as the combination of intellectual, social, and physical activities) is associated with cognitive change [6–8] and that decline in activity in older age is associated with decline in cognitive functioning. In addition to general activity, other studies have specifically targeted the association of physical activity with cognitive change. Indeed, a growing body of the literature highlights the potential benefits of physical activity on the structure and function of the brain [9, 10]. The first line of evidence for the relationship between physical activity and cognition comes from a number of cross-sectional studies demonstrating that physically active older adults have higher cognitive performance and functioning compared with less active older adults [11, 12]. However, the evidence derived from these cross-sectional studies is limited, as it is not. possible to draw conclusions in terms of more complex associations of change. Stronger evidence may be found in longitudinal studies. Longitudinal studies may be viewed as the second line of evidence, offering valuable information on the
Elasticity of Polydomain Liquid Crystal Elastomers
J. S. Biggins,M. Warner,K. Bhattacharya
Physics , 2009, DOI: 10.1016/j.jmps.2012.01.008
Abstract: We model polydomain liquid-crystal elastomers by extending the neo-classical soft and semi-soft free energies used successfully to describe monodomain samples. We show that there is a significant difference between polydomains cross-linked in homogeneous high symmetry states then cooled to low symmetry polydomain states and those cross-linked directly in the low symmetry polydomain state. For example, elastomers cross-linked in the isotropic state then cooled to a nematic polydomain will, in the ideal limit, be perfectly soft, and with the introduction of non-ideality, will deform at very low stress until they are macroscopically aligned. The director patterns observed in them will be disordered, characteristic of combinations of random deformations, and not disclination patterns. We expect these samples to exhibit elasticity significantly softer than monodomain samples. Polydomains cross-linked in the nematic polydomain state will be mechanically harder and contain characteristic schlieren director patterns. The models we use for polydomain elastomers are spatially heterogeneous, so rather than solving them exactly we elucidate this behavior by bounding the energies using Taylor-like (compatible test strain fields) and Sachs (constant stress) limits extended to non-linear elasticity. Good agreement is found with experiments that reveal the supersoft response of some polydomains. We also analyze smectic polydomain elastomers and propose that polydomain SmC* elastomers cross-linked in the SmA monodomain state are promising candidates for low field electrical actuation.
New Vacua of Gauged N=8 Supergravity
A. Khavaev,K. Pilch,N. P. Warner
Physics , 1998, DOI: 10.1016/S0370-2693(00)00795-4
Abstract: We analyze a particular SU(2) invariant sector of the scalar manifold of gauged N=8 supergravity in five dimensions, and find all the critical points of the potential within this sector. The critical points give rise to Anti-de Sitter vacua, and preserve at least an SU(2) gauge symmetry. Consistent truncation implies that these solutions correspond to Anti-de Sitter compactifications of IIB supergravity, and hence to possible near-horizon geometries of 3-branes. Thus we find new conformal phases of softly broken N=4 Yang--Mills theory. One of the critical points preserves N=2 supersymmetry in the bulk and is therefore completely stable, and corresponds to an N=1 superconformal fixed point of the Yang--Mills theory. The corresponding renormalization group flow from the N=4 point has c_{IR}/c_{UV} = 27/32. We also discuss the ten-dimensional geometries corresponding to these critical points.
57 second oscillations in Nova Centauri 1986 (V842 Cen)
P. A. Woudt,B. Warner,J. Osborne,K. Page
Physics , 2009, DOI: 10.1111/j.1365-2966.2009.14668.x
Abstract: High speed photometry in 2008 shows that the light curve of V842 Cen possesses a coherent modulation at 56.825 s, with sidebands at 56.598 s and 57.054 s. These have appeared since this nova remnant was observed in 2000 and 2002. We deduce that the dominant signal is the rotation period of the white dwarf primary and the sidebands are caused by reprocessing from a surface moving with an orbital period of 3.94 h. Thus V842 Cen is an intermediate polar (IP) of the DQ Herculis subclass, is the fastest rotating white dwarf among the IPs and is the third fastest known in a cataclysmic variable. As in other IPs we see no dwarf nova oscillations, but there are often quasi-periodic oscillations in the range 350 - 1500 s. There is a strong brightness modulation with a period of 3.78 h, which we attribute to negative superhumps, and there is an even stronger signal at 2.886 h which is of unknown origin but is probably a further example of that seen in GW Lib and some other systems. We used the Swift satellite to observe V842 Cen in the ultra-violet and in X-rays, although no periodic modulation was detected in the short observations. The X-ray luminosity of this object appears to be much lower than that of other IPs in which the accretion region is directly visible.
Multi-stakeholder platforms: integrating society in water resource management?
Warner, Jeroen;
Ambiente & Sociedade , 2005, DOI: 10.1590/S1414-753X2005000200001
Abstract: multi-stakeholder platforms are a currently popular concept in the international water world. it is however not a very well defined phenomenon. the present article unpacks the concept, proposes to see platforms as networks, and identifies two ′schools of thought′: social learning and negotiation. it attempts a preliminary typology of platforms encountered in real life, in which the comités de bacia in brazil, for all their shortcomings, come out as a relatively influential type. in closing, the article then identifies reasons for non-participation, suggesting that it is an inevitable corollary of organised participation.
Facilitation strategies to improve the use of evidence in integrated stroke care
Grace Warner
International Journal of Integrated Care , 2008,
Abstract:
Kommunale Versorgung, Verortung und Steuerung von Risiken psychischer Gesundheit Community Care and the Location and Governance of Risk in Mental Health La asistencia comunitaria y la localización y gobierno del riesgo en salud mental
Joanne Warner
Forum : Qualitative Social Research , 2006,
Abstract: Das Risikokonzept ist heute zentral für alle Bereiche von gesundheitlicher und sozialer Wohlfahrt in Gro britannien. Im Bereich psychischer Gesundheit und insbesondere seit den Ma nahmen zur kommunalen Versorgung in den 1990er Jahren kommt dem Konzept jedoch besondere Aufmerksamkeit zu. Dabei kamen bisher vor allem die Risiken in den Blick, die von Personen mit psychischen Erkrankungen oder in psychischer Not ausgehen, aber nicht die Risiken, mit denen diese selbst konfrontiert sind. Der vorliegende Beitrag beruht auf qualitativem Material, das mit Hilfe teilstandardisierter Interviews mit 39 Sozialarbeitern in England erhoben wurde, und entwickelt einen theoretischen Rahmen für die Risiken im Kontext des Dienstes für geistige Gesundheit. Anhand der Daten wird illustriert, dass sich die Bedeutung von Risiken für die Politik und die professionelle Praxis mit drei grundlegenden Konzepten fassen l sst: "gef hrliche Personen", "(psychotische) Erkrankung" und "soziale Kontexte". Zum einen verorteten Sozialarbeiter Risiken in "gef hrlichen Personen". Dabei stellte der junge schwarze Mann mit einer Schizophreniediagnose den Idealtypus eines gef hrlichen Individuums dar. Zudem wurden Risiken aber auch innerhalb einer Person verortet bzw. auf eine bestimmte Erkrankung bezogen. Schlie lich wurden Risiken sozialen Kontexten und spezifischen Umst nden zugeordnet, die gef hrliches Verhalten, so die befragten Sozialarbeiter, f rdern. Abschlie end wird gezeigt, wie der entwickelte theoretische Rahmen in anderen Kontexten nutzbringend angewendet werden kann. URN: urn:nbn:de:0114-fqs0601310 The concept of risk is now central to all areas of health and social welfare in the UK, although its exact character in relation to different groups varies. It has been argued that risk in mental health has been characterised by a preoccupation with the perceived risk of violence to others posed by those experiencing mental distress, particularly since the implementation of community care policies in the 1990s. The present paper draws on qualitative materials from semi-structured interviews with thirty-nine mental health social workers to demonstrate the significance for policy and practice of identifying where professionals see risk as being located. In the present study, three key sites were identified: firstly, risk was located in dangerous individuals, where the concept "high-risk" was particularly closely identified with young Black men with a diagnosis of schizophrenia. Secondly, social workers located risk in within-subject entities such as active psychotic illness, when it was
Science in Wonderland
Brian Warner
South African Journal of Science , 2010, DOI: 10.4102/sajs.v106i1/2.109
Abstract:
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