529 research outputs found
Effortful control, repetitive negative thinking and depression in adolescence
LITERATURE REVIEW: A systematic review of the associations between effortful control, repetitive negative thinking and depression in adolescence.
ABSTRACT: Background: Repetitive negative thinking (RNT) and the self-regulatory temperament, effortful control (EC), have been found to be important risk factors for the development of depressive symptoms. Furthermore, adolescence has been found to be a period of increased risk for developing depressive symptoms. The relationships between these risk pathways are not well understood during this period of development.
Objective: This systematic review aimed to evaluate the literature exploring the relationships RNT and EC have in accounting for depressive symptoms in adolescents. In particular, whether RNT and EC are associated with depressive symptoms, and whether EC moderates the effects of RNT on depressive symptoms.
Methods: Three databases and key journals were searched for studies measuring EC, RNT and depressive symptoms in 10-20 year olds. Study selection was undertaken by applying inclusion and exclusion criteria. The methodological quality of the included studies was assessed using a validated checklist. Inter-rater reliability was calculated for a random subsample of the search.
Results: Thirteen studies were selected for inclusion. There was evidence indicating that RNT was correlated with depressive symptoms both concurrently and prospectively. The evidence for a relationship between lower EC and higher levels of depressive symptoms was mixed. High quality studies concluded that EC and depressive symptoms are associated concurrently, but not over time. There is evidence that lower EC predicts RNT over time, and even spanning over childhood. Some evidence was found for EC as a moderator between RNT and depressive symptoms and this was also found when the relationship was prospective.
Conclusions: Whilst the reviewed literature had many strengths, there were large differences in how EC in particular, was measured. This resulted in a challenge synthesising the results and making clear conclusions. Future research would benefit from considering self-report and behavioural measures, and recognising the potential impact of stressful life events.
EMPIRICAL PAPER: Investigating associations between repetitive negative thinking, stress, and effortful control, and the development and maintenance of depression in adolescence: A follow-up study.
ABSTRACT: Background: Adolescence is a period of increased vulnerability for depressive symptoms (Twenge & Nolen-Hoeksema, 2002). Given the impact of emotional disorders on an individual, it is important to understand risk factors, and conversely, protective factors to inform effective interventions. Repetitive negative thinking (RNT) and the self-regulatory temperament, effortful control (EC), have been found to be important risk factors for the development of depressive symptoms and require further exploration in adolescence.
Objective: This study investigated whether RNT predicted changes in later depressive symptoms, and if so, whether this change was moderated by EC. The study examined these associations during emotional reactivity to a stressor (exams), and emotional recovery following the stressor.
Methods: Two samples with similar designs and measures were combined in this study. Two-hundred-and-fifty-five females completed Baseline questionnaires measuring life events, RNT, EC, and depressive symptoms. One-hundred-and-ninety-nine participants were followed up prior to their exams (Pre-exam), and 115 participants were followed up after their exams (Post-exam).
Results: The study first examined emotional reactivity to stress, finding that contrary to the literature, RNT did not predict depressive symptoms in response to stress, when controlling for Baseline depressive symptoms. EC did not significantly interact with RNT in predicting depressive symptoms. However, RNT was associated with emotional recovery from stress: RNT predicted levels of depressive symptoms following exams, when controlling for Pre-exam depressive symptoms. Furthermore, EC moderated this relationship, however contrary to the literature and predictions, this was not in the expected direction, with high levels of EC associated with high levels of depressive symptoms.
Conclusions: These findings suggest that despite the strengths of the study design, including a large sample at Baseline and follow up over a period of stress, hypothesized associations were not found during emotional reactivity to stress, but hypothesized associations were found during emotional recovery from stress. Recommendations are made for future studies, including recruiting sufficient number of males to the study
Role of the Hyaluronan Receptor, Stabilin-2/HARE, in Health and Disease
Stabilin-2/HARE is the primary clearance receptor for circulating hyaluronan (HA), a polysaccharide found in the extracellular matrix (ECM) of metazoans. HA has many biological functions including joint lubrication, ocular turgor pressure, skin elasticity and hydration, cell motility, and intercellular signaling, among many others. The regulatory system for HA content in the tissues, lymphatics, and circulatory systems is due, in part, to Stabilin-2/HARE. The activity of this receptor was discovered about 40 years ago (early 1980s), cloned in the mid-1990s, and has been characterized since then. Here, we discuss the overall domain organization of this receptor and how it correlates to ligand binding, cellular signaling, and its role in known physiological disorders such as cancer
PCB desorption kinetics under realistic shear and turbulence [progress report]
We hypothesize that the impact of PCB desorption from resuspended sediments depends upon the intensity of the resuspension (which scales to bottom stress in the absence of organisms), the rate at which each congener desorbs (which depends on the size and hydrophobicity of the chemical, the relative amount of 'labile' and 'resistant' forms, and the size distribution of the suspended particles), and the residence time of the particles in the water column (which depends on the time-variable water column turbulence regime and the particle settling velocities). In order to accurately quantify the impact of PCB desorption from Hudson River sediments, we are conducting experiments that realistically mimic bottom shear stress and water column turbulence and rapidly measure PCB congener release. The objectives of this study are to measure the kinetics of PCB congener desorption from Hudson River sediments under realistic bottom shear and water column turbulence conditions and to quantify the impact of shear stress and contaminant aging on PCB desorption kinetics
Single mitochondrial gene barcodes reliably identify sister-species in diverse clades of birds
Abstract
Background
DNA barcoding of life using a standardized COI sequence was proposed as a species identification system, and as a method for detecting putative new species. Previous tests in birds showed that individuals can be correctly assigned to species in ~94% of the cases and suggested a threshold of 10× mean intraspecific difference to detect potential new species. However, these tests were criticized because they were based on a single maternally inherited gene rather than multiple nuclear genes, did not compare phylogenetically identified sister species, and thus likely overestimated the efficacy of DNA barcodes in identifying species.
Results
To test the efficacy of DNA barcodes we compared ~650 bp of COI in 60 sister-species pairs identified in multigene phylogenies from 10 orders of birds. In all pairs, individuals of each species were monophyletic in a neighbor-joining (NJ) tree, and each species possessed fixed mutational differences distinguishing them from their sister species. Consequently, individuals were correctly assigned to species using a statistical coalescent framework. A coalescent test of taxonomic distinctiveness based on chance occurrence of reciprocal monophyly in two lineages was verified in known sister species, and used to identify recently separated lineages that represent putative species. This approach avoids the use of a universal distance cutoff which is invalidated by variation in times to common ancestry of sister species and in rates of evolution.
Conclusion
Closely related sister species of birds can be identified reliably by barcodes of fixed diagnostic substitutions in COI sequences, verifying coalescent-based statistical tests of reciprocal monophyly for taxonomic distinctiveness. Contrary to recent criticisms, a single DNA barcode is a rapid way to discover monophyletic lineages within a metapopulation that might represent undiscovered cryptic species, as envisaged in the unified species concept. This identifies a smaller set of lineages that can also be tested independently for species status with multiple nuclear gene approaches and other phenotypic characters
Teach Me In The Way I Learn: Education And The Internet Generation
College students learn differently than their professors. This disconnect between learning styles is not a new problem, however the problem has been magnified by the technology driven environment which exists in contemporary higher education. Students who grew up using computers and Playstations while surfing MySpace blogs and listening to their MP3 players are frequently neither receptive to traditional lectures nor able to relate to examples based on 20th century technologies. Numerous tools and technologies, however, can be used effectively to teach college students. This paper discusses several methods of addressing this disconnect through both pedagogical technique and classroom technologies
Fear and fearlessness in infants: A developmental approach
The main aim of this thesis was to improve our understanding of the development of
early inhibitory emotions and emotion regulation from infancy, and the role of these emotions
in early risk pathways. More specifically, this thesis investigated (1) the development of
fearful temperament, its stability over the first 3 years of life, and its associations with later
developing effortful control (EC) and guilt; (2) risk factors in infancy that predict later
externalising psychopathology; and (3) the development of EC, and its associations with fear
and guilt. Psychophysiological and observational measures were used, when available, to
examine these emotional systems as well as their role in predicting later psychopathology.
The thesis consists of 3 empirical chapters, investigating a sample of 70 typically developing
children in a longitudinal, prospective manner. Behavioural fear was stable over time, but
physiological fear peaked in year 2. Fearful infants continued to be fearful toddlers, and fear
in infancy predicted fearfulness 2 years later. Fear and guilt were associated, and we showed
for the first time that infant fear is a predictor of later developing guilt. EC increased from
year 2 to year 3, showed inter-individual stability across time, and girls’ ability for EC
surpassed the ability in boys. EC and guilt were not associated; however, EC and fear were
associated in year 3, suggesting that early fear does not regulate later EC. This thesis
identified two biomarkers in infancy for later psychopathology. A subgroup of toddlers with
internalising problems displayed higher heart rate in infancy, whereas skin conductance
arousal in infancy predicted aggressive behaviour in toddlers
Phylogenetic and coalescent analysis of three loci suggest that the Water Rail is divisible into two species, Rallus aquaticus and R. indicus
<p>Abstract</p> <p>Background</p> <p>Water Rails (<it>Rallus aquaticus</it>) inhabit fragmented freshwater wetlands across their Palearctic distribution. Disjunct populations are now thought to be morphologically similar over their vast geographic range, though four subspecies had been recognized previously. The fossil record suggests that Water Rails (<it>R. aquaticus</it>) were already spread across the Palearctic by the Pleistocene ~2 million years ago, and the oldest fossil remains thought to be closely related to the common ancestor of water rails date from the Pliocene.</p> <p>Results</p> <p>To investigate population structure in Water Rails at the genetic level we sequenced three independent loci: 686 base pairs (bp) of the mitochondrial DNA <it>COI </it>barcode; 618 bp of the intron <it>ADH5</it>; and 746 bp of the exon <it>PTPN12</it>. Phylogeographic analysis revealed that Water Rails breeding in eastern Asia (<it>R. a. indicus</it>, also known as the Brown-cheeked Rail) are strongly differentiated from the Water Rails in Western and Middle Asia and Europe (<it>R. a. aquaticus </it>and <it>R. a. korejewi</it>). The Kimura 3-parameter plus Gamma <it>COI </it>genetic distance between these two geographic groups was > 3%, and they differed by 18 diagnostic substitutions commensurate with differences between recently diverged sister species of birds. In spite of the low number of variable sites, the two nuclear loci supported this split. We estimated the split of the Brown-cheeked Rail and the Water Rail to have occurred ~534,000 years ago (95% CI 275,000-990,000 years ago). Fragmentation of the widespread ancestral population and eventual speciation of water rails is likely attributable to vicariance by a barrier formed by glacial cycles, continuous uplift of the Tibetan Plateau and increased sedimentation in deserts in southern Asia that originated in the Miocene.</p> <p>Conclusions</p> <p>Water Rails from East Asia were genetically differentiated from the ones breeding in Europe and Western to Middle Asia. Most of the genetic signal was from mitochondrial <it>COI</it>, and was corroborated by polymorphic sites in the two nuclear loci we employed. The split between these two lineages was estimated to occur in the Middle Pleistocene, when populations were isolated in disjunct wetlands with little or no gene flow. Independent evidence from differences in morphology and vocalizations in concert with genetic differentiation and a long history of isolation support recognition of the Brown-cheeked Rail breeding in East Asia as a separate species, <it>R. indicus</it>. The use of several independent loci is invaluable in inferring species trees from gene trees and in recognizing species limits.</p
1H, 13C, and 15N resonance assignments for the tandem PHD finger motifs of human CHD4
The plant homeodomain (PHD) zinc finger is a structural motif of about 40–60 amino acid residues found in many eukaryotic proteins that are involved in chromatin-mediated gene regulation. The human chromodomain helicase DNA binding protein 4 (CHD4) is a multi-domain protein that harbours, at its N-terminal end, a pair of PHD finger motifs (dPHD) connected by a ~30 amino acid linker. This tandem PHD motif is thought to be involved in targeting CHD4 to chromatin via its interaction with histone tails. Here we report the 1H, 13C and 15N backbone and side-chain resonance assignment of the entire dPHD by heteronuclear multidimensional NMR spectroscopy. These assignments provide the starting point for the determination of the structure, dynamics and histone-binding properties of this tandem domain pair
Assessing Graduate Teaching Development Programs for Impact on Future Faculty
Long-term training programs for teaching assistants have greater impactTraining programs for university teaching assistants (TAs) improve the quality of teaching and learning. But a new HEQCO study of short and long-term training programs at two Ontario universities finds that while both make important contributions, long programs had a greater impact.Assessing Graduate Teaching Development Programs for Impact on Future Faculty was conducted at the University of Windsor and Western University, whose teaching and learning centres offer a wide range of TA training programs -- short, orientation-style conferences and longer, intensive workshops throughout the year.Project descriptionThe study used self-reported measures of TAs’ attitudes to teaching and teaching self-efficacy before and after each program, combined with focus group interviews four months after program completion. The goal was to assess and compare the impact of the programs and to link specific types of programming to measurable outcomes. FindingsTeaching development programs help improve the teaching effectiveness of new TAs in a variety of ways, according to the study. TAs felt better prepared for their role as instructors after participating in training. Both short (one-day events) and long programs (20-40 hours) contributed to increased teaching self-efficacy and to an increase in student-focused approaches to teaching. The focus groups found that when TAs began to teach on their own, they were able to apply the teaching techniques, course design principles and student-focused approaches to teaching that they learn in TA training programs. Participants in short programs emphasized concrete teaching techniques for facilitating discussions, marking, asking effective questions and becoming more familiar with expectations for the teaching assistant role. Participants in longer programs demonstrated greater confidence in using principles of course design and alignment and articulating learning outcomes, and showed a greater depth of reflection on teaching. Long programs also created communities of TAs from a variety of disciplines, where discussion about teaching continued beyond the end of the program. Participants also shared innovative teaching techniques or course design strategies with their peers and with faculty members. The study found that both programs make an important contribution – but do so in different ways. Short programs serve as a gateway to further teaching development, allowing new graduate students to learn a few very practical teaching strategies and better understand the benefits of further training. Longer programs allow participants to build community and strategically prepare for careers in teaching, whether inside or outside academia.The authors note that it is important for teaching centres and departments to clearly communicate the differences between the outcomes of orientation-style and more in-depth programs.Further researchAddition research could explore long-term changes in TAs’ approaches to teaching after training, as well as the impact of TA training on student learning, say the authors, complementing the self-report measures used in this study with observer and student ratings of TA teaching in real classroom settings. Other HEQCO studies that explore teaching and TA development include a report on two University of Toronto TA training programs, a study of Western University’s international TA training programs and an overview of the evolution of teaching and learning centres in Ontario colleges and universities.Authors of Assessing Graduate Teaching Development Programs for Impact on Future Faculty are Nanda Dimitrov, Ken Meadows, Erika Kustra, Theimann Ackerson, Laura Prada, Nick Baker, Pierre Boulos, Gayle McIntyre and Michael K. Potter
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