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Search Results: 1 - 10 of 408704 matches for " Dan M. Mungas "
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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
Chinese-Language Montreal Cognitive Assessment for Cantonese or Mandarin Speakers: Age, Education, and Gender Effects
Ling Zheng,Evelyn L. Teng,Rohit Varma,Wendy J. Mack,Dan Mungas,Po H. Lu,Helena C. Chui
International Journal of Alzheimer's Disease , 2012, DOI: 10.1155/2012/204623
Abstract: The Montreal Cognitive Assessment Chinese-Language Los Angeles version (MoCA-ChLA) was developed and administered during an in-home interview to 1,192 participants (mean age 62.5 years, mean education 11.6 years) in a population-based Chinese American Eye Study (CHES) in Los Angeles. The MoCA-ChLA score (mean ± SD) was with little ceiling and no floor effects. The score increased with higher education, decreased with advancing age, and was not related to gender. Compared to the education 1–6 years group, the mean MoCA-ChLA score was 2.6 and 4.6 higher in the education 7–11 and 12–20 years groups, respectively. The Mandarin- ( ) and Cantonese- ( ) speaking subgroups performed comparably; Cronbach's alpha of the MoCA-ChLA score was 0.78 and 0.79 for these two groups, respectively. Item response theory analysis showed good discriminating power for executive function and memory. These properties support the MoCA-ChLA as a useful screening tool for aging and dementia studies for Mandarin or Cantonese speakers. 1. Introduction The Chinese American population is one of the most rapidly growing minorities in the United States [1, 2]. According to the USA Bureau of the Census (2010), the number of Chinese Americans increased 229% from 1.62 to 3.8 million from 1990 to 2010 [2]. One-third of Chinese Americans (1.25 million) reside in California, and the number of Chinese Americans with dementia is expected to more than triple in the next 30 years [3]. However, few studies have focused on the screening for cognitive impairment among Chinese-Americans. Linguistically and culturally appropriate cognitive screening tests to detect and stage cognitive impairment are needed to facilitate early detection and intervention. The lack of such instruments also limits the participation of Chinese Americans in cognitive and aging research. The Montreal Cognitive Assessment (MoCA) is a brief cognitive screening test designed to distinguish individuals with mild cognitive impairment (MCI) who perform in the normal range of the Mini-Mental State Examination (MMSE) from cognitively normal elderly [4]. Since Chinese Americans migrated primarily from Mainland China, Hong Kong, Macau, and Taiwan, the Chinese-speaking population in the USA consists of three major cultural subgroups whose primary dialect is Mandarin [Putonghua], Cantonese, or Taiwanese [5]. These three groups may use different words or expressions for some concepts and may differ in level of education. We therefore translated and adapted the MoCA for Mandarin-, Cantonese-, and Taiwanese-speaking Chinese Americans with
Multi-criteria decision model for retrofitting existing buildings
M. D. Bostenaru Dan
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2004,
Abstract: Decision is an element in the risk management process. In this paper the way how science can help in decision making and implementation for retrofitting buildings in earthquake prone urban areas is investigated. In such interventions actors from various spheres are involved. Their interests range among minimising the intervention for maximal preservation or increasing it for seismic safety. Research was conducted to see how to facilitate collaboration between these actors. A particular attention was given to the role of time in actors' preferences. For this reason, on decision level, both the processural and the personal dimension of risk management, the later seen as a task, were considered. A systematic approach was employed to determine the functional structure of a participative decision model. Three layers on which actors implied in this multi-criteria decision problem interact were identified: town, building and element. So-called 'retrofit elements' are characteristic bearers in the architectural survey, engineering simulations, costs estimation and define the realms perceived by the inhabitants. This way they represent an interaction basis for the interest groups considered in a deeper study. Such orientation means for actors' interaction were designed on other levels of intervention as well. Finally, an 'experiment' for the implementation of the decision model is presented: a strategic plan for an urban intervention towards reduction of earthquake hazard impact through retrofitting. A systematic approach proves thus to be a very good communication basis among the participants in the seismic risk management process. Nevertheless, it can only be applied in later phases (decision, implementation, control) only, since it serves verifying and improving solution and not developing the concept. The 'retrofit elements' are a typical example of the detailing degree reached in the retrofit design plans in these phases.
Videokonference i forskningsnettet - muligheder, erfaringer og teknologi
Dan M?nster
Tidsskriftet for Universiteternes Efter- og Videreuddannelse , 2004,
Abstract: F rste gang publiceret i UNEV nr. 3: Internet Video: Teknik og p dagogik m des p nettet, april - juni 2004, red. Jens D rup. ISSN 1603-5518. Videokonference anvendes i stigende grad af de danske universiteter, b de til samarbejde universiteterne imellem og til samarbejde med udenlandske partnere. Teknologien og netv rket leverer en kvalitet og stabilitet, der g r videokonference til et brugbart alternativ og supplement til fysiske m der eller tilstedev relsesundervisning. Forskningsnettet stiller den n dvendige infrastruktur til r dighed, som g r det lettere at anvende teknologien, og som giver mulighed for at koble to eller flere lokaliteter sammen i ét virtuelt m de. I denne artikel vil jeg, udover at beskrive teknologien, ogs komme med eksempler p , hvordan videokonference i de seneste r er blevet anvendt af de danske universiteter, og der vil blive givet konkrete anvisninger p , hvorledes man benytter Forskningsnettets videokonferencetjeneste. Endelig er der sidst i artiklen en ordliste og nogle referencer til yderligere l sning om emnet.
Multidisciplinary co-operation in building design according to urbanistic zoning and seismic microzonation
M. Bostenaru Dan
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2005,
Abstract: Research and practice in seismology and urban planning interfere concerning the impact of earthquakes on urban areas. The roles of sub-area wide or typological divisions of the town were investigated with the methodology of regression, regarding their contribution to urban earthquake risk management. The inductive data set comprised recovery, preparedness, mitigation and resilience planning. All timely constituted planning types are refound today as layers, as the zoning results are used by differently backgrounded actors: local authorities, civil protection, urban planners, civil engineers. In resilience planning, the urban system is complexly theoretised, then integratedly approached. The steady restructuring process of the urban organism is evident in a dynamic analysis. Although expressed materially, the 'urban-frame' is realised spiritually, space adaptation being also social. A retrospective investigation of the role of resilient individual buildings within the urban system of Bucharest, Romania, was undertaken, in order to learn systemic lessons considering the street, an educational environment. (In)formation in the study and decision making process stay in a reciprocal relationship, both being obliged in the (in)formation of the public opinion. For a complete view on resilience, both zoning types, seismic and urbanistic, must be considered and through their superposition new sub-area wide divisions of the town appear, making recommendations according to the vulnerability of the building type.
Review of retrofit strategies decision system in historic perspective
M. D. Bostenaru Dan
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2004,
Abstract: Urban development is a process. In structuring and developing its phases different actors are implied, who act under different, sometimes opposite, dynamic conditions and within different reference systems. This paper aims to explore the contribution of participatism to disaster mitigation, when this concerns earthquake impact on urban settlements, through the support provided to multi-criteria decision in matters of retrofit. The research broadness in field of decision making on one side and the lack of a specific model for the retrofit of existing buildings on another side led to an extensive review of the state of the art in related models to address the issue. Core idea in the selection of existing models has been the preoccupation for collaborative issues, in other words, the consideration for the different actors implied in the planning process. The historic perspective on participative planning models is made from the view of two generations of citizen implication. The first approaches focus on the participation of the building owner/inhabitant in the planning process of building construction. As current strategies building rehabilitation and selection from alternative retrofit strategies are presented. New developments include innovative models using the internet or spatial databases. The investigated participation approaches show, that participation and communication as a more comprehensive term are an old topic in the field politics-democratisation-urbanism. In all cases it can be talked of 'successful learning processes', of the improvement of the level of the professional debate. More than 30 years history of participation marked a transition in understanding the concept: from participation, based on a central decision process leading to a solution controlled and steered by the political-administrative system, to communication, characterised by simultaneous decision processes taking place outside politics and administration in co-operative procedures.
Mineralization, Grain Growth and Disk Structure: Observations of the Evolution of Dust in Protoplanetary Disk
Dan M. Watson
Physics , 2009,
Abstract: During the past five years, the Spitzer Space Telescope and improved ground-based facilities have enabled a huge increase in the number of circumstellar disks, around young stars of Solar mass or smaller, in which the composition of the solid component has been studied with complete mid-infrared spectra. With these samples we can assess observationally the evolution of dust through the planet-forming era, in parallel with the evolution of the composition and structure of protoplanetary disks. Here we will review the progress in this endeavour, with emphasis on objects in nearby associations and star-formation regions, and on the methods by which dust composition is determined from the infrared spectra of young stellar objects.
Stability Threshold for Multiadditive and Symmetric Mappings
Dan M. Daianu
Mathematics , 2014,
Abstract: We extend the Z. Gajda's result concerning the stability threshold for additive mappings to the n-additive and symmetric functions.
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