From maternal tending to adolescent befriending: The adolescent transition of social support

Attachment theory holds that parental relationships have lifelong effects on offspring social lives. The tend-and-befriend hypothesis posits that female friendships among humans evolved as part of a primate-wide coping mechanism to mediate stress by relying on social support. Here we bridge developmental and evolutionary frameworks to examine adolescent girls’ perception of their reliance on female friendship for social support, how perceptions of parental relationships affect peer relationships, and the extent to which parent and peer relationships buffer depressive symptoms. We predict perceived maternal relationship quality will be positively associated with close female friendships, and maternal relationships, paternal relationships, and female friendship will buffer depressive symptoms. Participants were adolescent girls from a summer science camp (N = 95). Participants filled out demographic information, social network surveys, the Parent-Adolescent Communication Scale, and the Center for Epidemiology Depression Scale. Data was analyzed with Pearson's correlations, t tests, and path analysis. Adolescent girls with few female friends, compared with girls who had more than two very close female friends, experienced more depressive symptoms (t = 3.382, p = .001, D = 0.784). Adolescent girls with few female friends experienced more depressive symptoms compared to girls with two or more very close female friends (t = 3.382, p = .001, D = 0.784). Stronger maternal and paternal relationships were associated with having more female friends (maternal: t = −3.213, p = .003, D = 0.837; paternal: t = −2.432; p = .017). In the path analysis model, only maternal relationship quality significantly predicted female friendship category (β = .33, CR = 2.770, p < .006). Furthermore, participants with two or more very close female friends and higher paternal relationship quality had significantly fewer depressive symptoms (friends; β = −.19, CR = −2.112, p = .035; paternal: β = −.33, CR = −3.220, p < .001), and older participants had more depressive symptoms (β = .17, CR = −1.931, p = .036). These results provide additional support for the tend-and-befriend hypothesis, suggesting that maternal tending sets the stage for close female friendships.     

Morphophysiological responses,bioaccumulation and tolerance of Alternanthera tenella Colla (Amaranthaceae) to excess copper under in vitro conditions

Plant Cell, Tissue and Organ Culture (PCTOC) - Copper (Cu) is an essential metal and both its deficiency and excess has negative effects on the growth and physiology of plants. Some plant species...     

Sim-SPR: an Open-Source Surface Plasmon Resonance Simulator for Academic and Industrial Purposes

Plasmonics - In this paper, an open-source simulation tool is proposed to evaluate the SPR effect considering a multilayer structure. The open-source simulator is called Sim-SPR and it follows the...     

Ultrastructural histogenesis of chicken myocardium]

The structure of the ventricular myocardium of the chick embryo was studied from the 4th day of incubation until one day after hatching. Special attention was paid to the differenciation of myofibrils, their branching at the level of stria Z and their relations with desmosomes.     

Codon Usage Methods for Horizontal Gene Transfer Detection Generate an Abundance of False Positive and False Negative Results

Bacteria acquire new DNA in a process known as horizontal gene transfer (HGT). To investigate the evolutionary impact of this transfer of DNA, various methods have been developed to detect past HGT events. For example, codon usage-based methods detect the presence of transferred genes by identifying atypical patterns of codon usage. However, some inherited genes exhibit atypical codon usage and some transferred genes have codon usage patterns similar to those of the inherited genes. In this study, we used a comparative phylogenetic approach with Methylobacterium and Caulobacter species to demonstrate that even well-designed codon usage methods fail to detect many HGT events and generate a high rate of false positives (60–75 %) and false negatives (23–61 %). Therefore, we recommend caution when employing codon usage methods to identify transferred genes and suggest that the rapidly increasing availability of bacterial genome sequences makes the phylogenetic approach the method of choice.     

Chromosomal studies on Coscoroba coscoroba (Aves: Anseriformes) reinforce the Coscoroba–Cereopsis clade

The Coscoroba (Coscoroba coscoroba), endemic to southern South America, is traditionally considered as an early branch from the common ancestor leading to true geese and swans. Recently, an interesting association between the Coscoroba and Cape Barren goose (Cereopsis novaehollandiae) as sister groups has been proposed. We present here the characterization of the karyotype of C. coscoroba using whole chromosome probes derived from Gallus gallus macrochromosomes. Our data showed that C. coscoroba has the highest diploid number among Anseriformes (2n = 98), and the conservation of macrochromosome pairs 1–10 indicates that the increase in diploid number has occurred by fission events involving only the microchromosomes. Moreover, the similarity between the diploid numbers of C. coscoroba (2n = 98) and Cereopsis novaehollandiae (2n = 92) reinforces the phylogenetic position of these two species as sister groups, considering that other species of geese and swans have diploid numbers close to 2n = 80. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111 , 274–279.