197 research outputs found
A functional polymorphism under positive evolutionary selection in ADRB2 is associated with human intelligence with opposite effects in the young and the elderly
Comparative genomics offers a novel approach to unravel the genetic basis of complex traits. We performed a two stage analysis where genes ascertained for enhanced protein evolution in primates are subsequently searched for the presence of non-synonymous coding SNPs in the current human population at amino acid sites that differ between humans and chimpanzee. Positively selected genes among primates are generally presumed to determine phenotypic differences between humans and chimpanzee, such as the enhanced cognitive ability of our species. Amino acid substitutions segregating in humans at positively selected amino acid sites are expected to affect phenotypic differences among humans. Therefore we conducted an association study in two family based cohorts and one population based cohort between cognitive ability and the most likely candidate gene among the five that harbored more than one such polymorphism. The derived, human-specific allele of the beta-2 adrenergic receptor Arg16Gly polymorphism was found to be the increaser allele for performance IQ in the young, family based cohort but the decreaser allele for two different measures of cognition in the large Scottish cohort of unrelated individuals. The polymorphism is known to affect signaling activity and modulation of beta-2 adrenergic signaling has been shown to adjust memory consolidation, a trait related to cognition. The opposite effect of the polymorphism on cognition in the two age classes observed in the different cohorts resembles the effect of ADRB2 on hypertension, which also has been reported to be age dependent. This result illustrates the relevance of comparative genomics to detect genes that are involved in human behavior. © 2008 Springer Science+Business Media, LLC
The Mediating Role of Rumination in the Relation Between Quality of Attachment Relations and Depressive Symptoms in Non-Clinical Adolescents
This study examined associations between indices of the quality of attachment relationships of adolescents with parents and peers, rumination, and symptoms of depression. More specifically, a mediation model was investigated in which rumination was hypothesized to mediate the relation between quality of attachment relations and symptoms of depression. A total of 455 high school students completed a battery of questionnaires, including quality of attachment relations, rumination, and depression. Results showed that most indices of quality of attachment relations were significantly associated with rumination and symptoms of depression. When examining the relative contribution of these variables in explaining variance in depression symptoms, trust in parents, communication with peers, and alienation from peers accounted for a significant portion of the variance in depression scores. Finally, the relation between communication with peers and depressive symptoms was fully mediated by rumination, whereas partial mediation was found for the relations between parental trust and depressive symptoms, and between alienation from peers and depressive symptoms. Implications of the findings may be that the treatment of depression in adolescence should consist of both cognitive interventions aimed at targeting ruminative thinking as well as a focus on interpersonal relationships of the adolescent with parents and peers
To what extent does IQ 'explain' socio-economic variations in function?
<p>Abstract</p> <p>Background</p> <p>The aims of this study were to examine the extent to which higher intellectual abilities protect higher socio-economic groups from functional decline and to examine whether the contribution of intellectual abilities is independent of childhood deprivation and low birth weight and other socio-economic and developmental factors in early life.</p> <p>Methods</p> <p>The Maastricht Aging Study (MAAS) is a prospective cohort study based upon participants in a registration network of general practices in The Netherlands. Information was available on 1211 men and women, 24 – 81 years old, who were without cognitive impairment at baseline (1993 – 1995), who ever had a paid job, and who participated in the six-year follow-up. Main outcomes were longitudinal decline in important components of quality of life and successful aging, i.e., self-reported physical, affective, and cognitive functioning.</p> <p>Results</p> <p>Persons with a low occupational level at baseline showed more functional decline than persons with a high occupational level. Socio-economic and developmental factors from early life hardly contributed to the adult socio-economic differences in functional decline. Intellectual abilities, however, took into account more than one third of the association between adult socio-economic status and functional decline. The contribution of the intellectual abilities was independent of the early life factors.</p> <p>Conclusion</p> <p>Rather than developmental and socio-economic characteristics of early life, the findings substantiate the importance of intellectual abilities for functional decline and their contribution – as potential, but neglected confounders – to socio-economic differences in functioning, successful aging, and quality of life. The higher intellectual abilities in the higher socio-economic status groups may also underlie the higher prevalences of mastery, self-efficacy and efficient coping styles in these groups.</p
Hiding from the Moonlight: Luminosity and Temperature Affect Activity of Asian Nocturnal Primates in a Highly Seasonal Forest
The effect of moonlight and temperature on activity of slow lorises was previously little known and this knowledge might be useful for understanding many aspects of their behavioural ecology, and developing strategies to monitor and protect populations. In this study we aimed to determine if the activity of the pygmy loris (Nycticebus pygmaeus) is affected by ambient temperature and/or moonlight in a mixed deciduous forest. We radio-collared five females and five males in the Seima Protection Forest, Cambodia, in February to May, 2008 and January to March, 2009 and recorded their behaviour at 5 minutes intervals, totalling 2736 observations. We classified each observation as either inactive (sleeping or alert) or active behaviour (travel, feeding, grooming, or others). Moon luminosity (bright/dark) and ambient temperature were recorded for each observation. The response variable, activity, was binary (active or inactive), and a logit link function was used. Ambient temperature alone did not significantly affect mean activity. Although mean activity was significantly affected by moonlight, the interaction between moonlight and temperature was also significant: on bright nights, studied animals were increasingly more active with higher temperature; and on dark nights they were consistently active regardless of temperature. The most plausible explanation is that on bright cold nights the combined risk of being seen and attacked by predators and heat loss outweigh the benefit of active behaviours
Peer Perceptions of Social Skills in Socially Anxious and Nonanxious Adolescents
Previous studies using adult observers are inconsistent with regard to social skills deficits in nonclinical socially anxious youth. The present study investigated whether same age peers perceive a lack of social skills in the socially anxious. Twenty high and 20 low socially anxious adolescents (13–17 years old) were recorded giving a 5-min speech. Unfamiliar peer observers (12–17 years old) viewed the speech samples and rated four social skills: speech content, facial expressions, posture and body movement, and way of speaking. Peer observers perceived high socially anxious adolescents as significantly poorer than low socially anxious adolescents on all four social skills. Moreover, for all skills except facial expressions, group differences could not be attributed to adolescents’ self-reported level of depression. We suggest that therapists take the perceptions of same age peers into account when assessing the social skills of socially anxious youth
Co-rumination buffers the link between social anxiety and depressive symptoms in early adolescence
Objectives:
We examined whether co-rumination with online friends buffered the link between social anxiety and depressive symptoms over time in a community sample.
Methods:
In a sample of 526 participants (358 girls; Mage = 14.05) followed at three time points, we conducted a latent cross-lagged model with social anxiety, depressive symptoms, and co-rumination, controlling for friendship stability and friendship quality, and adding a latent interaction between social anxiety and co-rumination predicting depressive symptoms.
Results:
Social anxiety predicted depressive symptoms, but no direct links between social anxiety and co-rumination emerged. Instead, co-rumination buffered the link between social anxiety and depressive symptoms for adolescents with higher but not lower levels of social anxiety.
Conclusions:
These findings indicate that co-rumination exerted a positive influence on interpersonal relationships by diminishing the influence from social anxiety on depressive symptoms over time
Predicting change in quality of life from age 79 to 90 in the Lothian Birth Cohort 1921
Purpose: Quality of life (QoL) decreases in very old age, and is strongly related to health outcomes and mortality. Understanding the predictors of QoL and change in QoL amongst the oldest old may suggest potential targets for intervention. This study investigated change in QoL from age 79 to 90 years in a group of older adults in Scotland, and identified potential predictors of that change.
Method: Participants were members of the Lothian Birth Cohort 1921 who attended clinic visits at age 79 (n = 554) and 90 (n = 129). Measures at both time points included QoL (WHOQOL-BREF: four domains and two single items), anxiety and depression, objective health, functional ability, self-rated health, loneliness, and personality.
Results: Mean QoL declined from age 79 to 90. Participants returning at 90 had scored significantly higher at 79 on most QoL measures, and exhibited better objective health and functional ability, and lower anxiety and depression than non-returners. Hierarchical multiple regression models accounted for 20.3–56.3% of the variance in QoL at age 90. Baseline QoL was the strongest predictor of domain scores (20.3–35.6% variance explained), suggesting that individual differences in QoL judgements remain largely stable. Additional predictors varied by the QoL domain and included self-rated health, loneliness, and functional and mood decline between age 79 and 90 years.
Conclusions: This study has identified potential targets for interventions to improve QoL in the oldest old. Further research should address causal pathways between QoL and functional and mood decline, perceived health and loneliness
Relative Impacts of Adult Movement, Larval Dispersal and Harvester Movement on the Effectiveness of Reserve Networks
Movement of individuals is a critical factor determining the effectiveness of
reserve networks. Marine reserves have historically been used for the management
of species that are sedentary as adults, and, therefore, larval dispersal has
been a major focus of marine-reserve research. The push to use marine reserves
for managing pelagic and demersal species poses significant questions regarding
their utility for highly-mobile species. Here, a simple conceptual
metapopulation model is developed to provide a rigorous comparison of the
functioning of reserve networks for populations with different admixtures of
larval dispersal and adult movement in a home range. We find that adult movement
produces significantly lower persistence than larval dispersal, all other
factors being equal. Furthermore, redistribution of harvest effort previously in
reserves to remaining fished areas (‘fishery squeeze’) and fishing
along reserve borders (‘fishing-the-line’) considerably reduce
persistence and harvests for populations mobile as adults, while they only
marginally changes results for populations with dispersing larvae. Our results
also indicate that adult home-range movement and larval dispersal are not simply
additive processes, but rather that populations possessing both modes of
movement have lower persistence than equivalent populations having the same
amount of ‘total movement’ (sum of larval and adult movement spatial
scales) in either larval dispersal or adult movement alone
Universal Plant DNA Barcode Loci May Not Work in Complex Groups: A Case Study with Indian Berberis Species
BACKGROUND: The concept of DNA barcoding for species identification has gained considerable momentum in animals because of fairly successful species identification using cytochrome oxidase I (COI). In plants, matK and rbcL have been proposed as standard barcodes. However, barcoding in complex genera is a challenging task. METHODOLOGY AND PRINCIPAL FINDINGS: We investigated the species discriminatory power of four reportedly most promising plant DNA barcoding loci (one from nuclear genome--ITS, and three from plastid genome--trnH-psbA, rbcL and matK) in species of Indian Berberis L. (Berberidaceae) and two other genera, Ficus L. (Moraceae) and Gossypium L. (Malvaceae). Berberis species were delineated using morphological characters. These characters resulted in a well resolved species tree. Applying both nucleotide distance and nucleotide character-based approaches, we found that none of the loci, either singly or in combinations, could discriminate the species of Berberis. ITS resolved all the tested species of Ficus and Gossypium and trnH-psbA resolved 82% of the tested species in Ficus. The highly regarded matK and rbcL could not resolve all the species. Finally, we employed amplified fragment length polymorphism test in species of Berberis to determine their relationships. Using ten primer pair combinations in AFLP, the data demonstrated incomplete species resolution. Further, AFLP analysis showed that there was a tendency of the Berberis accessions to cluster according to their geographic origin rather than species affiliation. CONCLUSIONS/SIGNIFICANCE: We reconfirm the earlier reports that the concept of universal barcode in plants may not work in a number of genera. Our results also suggest that the matK and rbcL, recommended as universal barcode loci for plants, may not work in all the genera of land plants. Morphological, geographical and molecular data analyses of Indian species of Berberis suggest probable reticulate evolution and thus barcode markers may not work in this case
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