Magnetic resonance imaging volumetry studies report inverted U-patterns with increasing white-matter (WM) volume into middle age suggesting protracted WM maturation compared with the cortical gray matter. Diffusion tensor imaging (DTI) is sensitive to degree and direction of water permeability in biological tissues, providing in vivo indices of WM microstructure. The aim of this cross-sectional study was to delineate age trajectories of WM volume and DTI indices in 430 healthy subjects ranging 8-85 years of age. We used automated regional brain volume segmentation and tract-based statistics of fractional anisotropy, mean, and radial diffusivity as markers of WM integrity. Nonparametric regressions were used to fit the age trajectories and to estimate the timing of maximum development and deterioration in aging. Although the volumetric data supported protracted growth into the sixth decade, DTI indices plateaued early in the fourth decade across all tested regions and then declined slowly into late adulthood followed by an accelerating decrease in senescence. Tractwise and voxel-based analyses yielded regional differences in development and aging but did not provide ample evidence in support of a simple last-in-first-out hypothesis of life-span changes.
Mobile phone text messaging is a potentially powerful tool for behavior change because it is widely available, inexpensive, and instant. This systematic review provides an overview of behavior change interventions for disease management and prevention delivered through text messaging. Evidence on behavior change and clinical outcomes was compiled from randomized or quasi-experimental controlled trials of text message interventions published in peer-reviewed journals by June 2009. Only those interventions using text message as the primary mode of communication were included. Study quality was assessed by using a standardized measure. Seventeen articles representing 12 studies (5 disease prevention and 7 disease management) were included. Intervention length ranged from 3 months to 12 months, none had long-term follow-up, and message frequency varied. Of 9 sufficiently powered studies, 8 found evidence to support text messaging as a tool for behavior change. Effects exist across age, minority status, and nationality. Nine countries are represented in this review, but it is problematic that only one is a developing country, given potential benefits of such a widely accessible, relatively inexpensive tool for health behavior change. Methodological issues and gaps in the literature are highlighted, and recommendations for future studies are provided.
BACKGROUND: It is widely believed that cancer can be prevented by high intake of fruits and vegetables. However, inconsistent results from many studies have not been able to conclusively establish an inverse association between fruit and vegetable intake and overall cancer risk. METHODS: We conducted a prospective analysis of the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort to assess relationships between intake of total fruits, total vegetables, and total fruits and vegetables combined and cancer risk during 1992-2000. Detailed information on the dietary habit and lifestyle variables of the cohort was obtained. Cancer incidence and mortality data were ascertained, and hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using multivariable Cox regression models. Analyses were also conducted for cancers associated with tobacco and alcohol after stratification for tobacco smoking and alcohol drinking. RESULTS: Of the initial 142 605 men and 335 873 women included in the study, 9604 men and 21 000 women were identified with cancer after a median follow-up of 8.7 years. The crude cancer incidence rates were 7.9 per 1000 person-years in men and 7.1 per 1000 person-years in women. Associations between reduced cancer risk and increased intake of total fruits and vegetables combined and total vegetables for the entire cohort were similar (200 g/d increased intake of fruits and vegetables combined, HR = 0.97, 95% CI = 0.96 to 0.99; 100 g/d increased intake of total vegetables, HR = 0.98, 95% CI = 0.97 to 0.99); intake of fruits showed a weaker inverse association (100 g/d increased intake of total fruits, HR = 0.99, 95% CI = 0.98 to 1.00). The reduced risk of cancer associated with high vegetable intake was restricted to women (HR = 0.98, 95% CI = 0.97 to 0.99). Stratification by alcohol intake suggested a stronger reduction in risk in heavy drinkers and was confined to cancers caused by smoking and alcohol. CONCLUSIONS: A very small inverse association between intake of total fruits and vegetables and cancer risk was observed in this study. Given the small magnitude of the observed associations, caution should be applied in their interpretation.
Market size matters for innovation and hence for productivity. Improved access to foreign markets will thus encourage firms to simultaneously export and invest in raising productivity. We examine this insight using the responses of Canadian plants to the elimination of U. S. tariffs. Unique "plant-specific" tariff cuts serve as an instrument for changes in exporting. We find that Canadian plants that were induced by the tariff cuts to start exporting or to export more (a) increased their labor productivity, (b) engaged in more product innovation, and (c) had higher adoption rates for advanced manufacturing technologies. Further, these responses were heterogeneous.
Parkinson's disease (PD) is characterized by striatal dopamine depletion, especially in the posterior putamen. The dense connectivity profile of the striatum suggests that these local impairments may propagate throughout the whole cortico-striatal network. Here we test the effect of striatal dopamine depletion on cortico-striatal network properties by comparing the functional connectivity profile of the posterior putamen, the anterior putamen, and the caudate nucleus between 41 PD patients and 36 matched controls. We used multiple regression analyses of resting-state functional magnetic resonance imaging data to quantify functional connectivity across different networks. Each region had a distinct connectivity profile that was similarly expressed in patients and controls: the posterior putamen was uniquely coupled to cortical motor areas, the anterior putamen to the pre-supplementary motor area and anterior cingulate cortex, and the caudate nucleus to the dorsal prefrontal cortex. Differences between groups were specific to the putamen: although PD patients showed decreased coupling between the posterior putamen and the inferior parietal cortex, this region showed increased functional connectivity with the anterior putamen. We conclude that dopamine depletion in PD leads to a remapping of cerebral connectivity that reduces the spatial segregation between different cortico-striatal loops. These alterations of network properties may underlie abnormal sensorimotor integration in PD.
We explored the effects of aging on 2 large-scale brain networks, the default mode network (DMN) and the task-positive network (TPN). During functional magnetic resonance imaging scanning, young and older participants carried out 4 visual tasks: detection, perceptual matching, attentional cueing, and working memory. Accuracy of performance was roughly matched at 80% across tasks and groups. Modulations of activity across conditions were assessed, as well as functional connectivity of both networks. Younger adults showed a broader engagement of the DMN and older adults a more extensive engagement of the TPN. Functional connectivity in the DMN was reduced in older adults, whereas the main pattern of TPN connectivity was equivalent in the 2 groups. Age-specific connectivity also was seen in TPN regions. Increased activity in TPN areas predicted worse accuracy on the tasks, but greater expression of a connectivity pattern associated with a right dorsolateral prefrontal TPN region, seen only in older adults, predicted better performance. These results provide further evidence for age-related differences in the DMN and new evidence of age differences in the TPN. Increased use of the TPN may reflect greater demand on cognitive control processes in older individuals that may be partially offset by alterations in prefrontal functional connectivity.
Many studies have found that seemingly unconnected behaviors are correlated into behavioral syndromes. These behavioral syndromes may be the consequence of interindividual variation in life-history strategies. Only few studies have investigated the role of behavioral syndromes in cooperatively breeding species, despite the fact that one would expect particular large variation in behavior clue to the wealth of life-history decisions a cooperative breeder faces. In a longitudinal study, we repeatedly tested individuals of the cooperatively breeding cichlid Neolamprologus pulcher for exploration, boldness, and aggression and tested whether these behaviors were sex specific; whether they were interrelated; and whether they were connected to growth and to 2 major life-history decisions, helping, and dispersal. In both sexes, explorative behavior was correlated over time, even though after sexual maturity males increased their exploration rate. In both sexes, exploration, boldness, and aggression correlated when mature, and in females, helping behavior was part of the syndrome. No relationships with growth were detected. Helping and dispersal were related to each other in males, whereas females hardly dispersed. We suggest that the differences in the life histories between males and females (male dispersal vs. female philopatry) lead to the differences in behavioral types observed and also to the differences in the stability of the behavioral syndromes between the sexes. The links between dispersal and helping in males and the behavioral types and helping in females highlight the necessity to study multiple traits to understand the evolution and maintenance of variation in cooperative behavior.
The Carbohydrate-Active Enzyme (CAZy) database provides a rich set of manually annotated enzymes that degrade, modify, or create glycosidic bonds. Despite rich and invaluable information stored in the database, software tools utilizing this information for annotation of newly sequenced genomes by CAZy families are limited. We have employed two annotation approaches to fill the gap between manually curated high-quality protein sequences collected in the CAZy database and the growing number of other protein sequences produced by genome or metagenome sequencing projects. The first approach is based on a similarity search against the entire nonredundant sequences of the CAZy database. The second approach performs annotation using links or correspondences between the CAZy families and protein family domains. The links were discovered using the association rule learning algorithm applied to sequences from the CAZy database. The approaches complement each other and in combination achieved high specificity and sensitivity when cross-evaluated with the manually curated genomes of Clostridium thermocellum ATCC 27405 and Saccharophagus degradans 2-40. The capability of the proposed framework to predict the function of unknown protein domains and of hypothetical proteins in the genome of Neurospora crassa is demonstrated. The framework is implemented as a Web service, the CAZymes Analysis Toolkit, and is available at http://cricket.ornl.gov/cgi-bin/cat.cgi.
In this article. marking the 65th anniversary of the Journal of we offer a broad-brush overview of the new synthesis between neuroscientific and psychological approaches to cognitive aging. We provide a selective review of brain imaging studies and their relevance to mechanisms of cognitive aging first identified primarily from behavioral measurements. We also examine some new key discoveries. including evidence favoring plasticity and compensation that have emerged specifically from using cognitive neuroscience methods to study healthy aging. We then summarize several recent neurocognitive theories of aging, including our own model the Scaffolding Theory of Aging and Cognition. We close by discussing some newly emerging trends and future research trajectories for investigating the aging in and bram.