1,721,843 research outputs found
BDNF moderates early environmental risk factors for for anxiety in mouse
No full textAnxiety is known to be influenced by both adverse childhood experiences and genetic susceptibility factors. A polymorphism in the brain-derived neurotrophic
factor (BDNF) gene modulates the association between adverse early experiences and risk for anxiety and depression in adulthood. An animal model of this
gene-by-environment risk factor is lacking. Using two different early environmental manipulations, we found that a heterozygous null mutation in the mouse BDNF gene moderated the long-term effect of maternal care on innate anxiety behavior. Although changes in maternal care were associated with mild changes in anxiety in wild-type mice, this effect was magnified in heterozygous null BDNF mice with high- and lowmaternal care associated with low and high levels,
respectively, of avoidance behavior as measured in the open field and elevated plus maze tests. These data argue for an increased sensitivity to early environmental influences of mice with reduced BDNF function and support the important role of this neurotrophic factor in the developmental plasticity of brain circuits controlling anxiety
Mouse models of the 5-HTTLPR × stress risk factor for depression
No full textThe incidence of mood disorders is known to be influenced by both genetic as well as environmental factors. Increasingly, however it is becoming clear that few genetic and environmental factors act alone, but that instead they regularly act in concert to determine predisposition to psychiatric disorders. Quite a few cases now have been reported in which stratification of subjects by exposure to environmental pathogens has been shown to alter the association between specific genetic variants and mental illness. The best studied of such measured gene-by-environment risk factors for mental illness is the increased risk for major depression reported among persons carrying the short variant (S allele) of a functional polymorphism in the serotonin transporter (5-HTT, SLC6A4) gene promoter and who have been exposed to stressful life events. Recently, a large number of laboratories have tried to model the interaction between 5-HTTLPR genotype and early/adult stress in mouse. Findings from their studies have helped to define the rodent orthologs of the environmental stressors and behavioral traits involved in risk for depression. Furthermore, several of these studies attempted to identify changes in molecular substrates that might underlie the 5-HTT x stress risk factor, pointing to the hippocampus and frontal cortex as critical brain structures involved in the interaction between 5-HTT gene variation and early and adult stress, respectively. These results will serve to help inform clinical research into the origins of major depression and other mental illnesses with interacting genetic and environmental risk factors
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Genetic variation in the serotonin transporter gene influences adult attachment style
No full textObjective: To ascertain if the 5-HTTLPR short allele was associated with an insecure style of attachment in a mixed sample of healthy subjects and psychiatric patients. Method: Three hundred and thirty five adults (222 healthy subjects and 113 psychiatric patients) were genotyped for the 5-HTTLPR serotonin transporter polymorphism. Adult attachment style was assessed by using the Relationship Questionnaire (RQ). The personality trait of harm avoidance was assessed by using the Temperament and Character Inventory (TCI). The depression subscale of the Profile of Mood States (POMS-D) was used to assess mood state. Harm avoidance and depression were measured to control their potential confounding effects on the relationship between the 5-HTTLPR serotonin transporter polymorphism and adult attachment style.Results: We found a significant association between insecure attachment and the 5-HTTLPR short allele. Separate analyses in the subcohorts of healthy subjects and psychiatric patients confirmed the association between attachment style and 5-HTTLPR. Such an association was not a byproduct of the relationship between the serotonin transporter polymorphism and neuroticism or negative affectivity because insecure attachment, but not the harm avoidance scale of the TCI, was associated with the short variant of 5-HTTLPR. Moreover, inclusion of harm avoidance and depressive symptoms into a multiple regression model did not weaken the significant correlation between the 5-HTTLPR and insecure attachment. The effect size seen in our study (Cramer’s phi = 0.15-0.21 approximately corresponding to Cohen’s d = 0.30-0.40) compares favorably to those reported in previous studies of association between the 5-HTTLPR polymorphism and personality traits. Conclusions: This study suggests that part of the variation in adult attachment styles can be accounted for by genetic differences among individual
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