68 research outputs found
A qualitative study of relational aggression in sixth grade girls
Middle school can be a time of great upheaval and unfamiliar footing for a new sixth grader. When students enter middle school, the peer hierarchy and social dynamics of elementary school are often shifted in ways that can be confusing and intimidating. Many new things are expected of a sixth grader that was not expected from a fifth grader. Suddenly there are different teachers for all the classes. There is a choice of classes to take, homework, there is a schedule to memorize. Students are asked to take the initiative and decide what they want to do, rather than having it decided for them by the adults around them. For many students this transition offers a sense of impending adulthood - growing-up - and it is an intimidating time for many
Agree or not agree? The role of cognitive and affective processes in group disagreements
We develop and test a theoretical framework for understanding how cognitive and affective processes (cognitive and affective integration) influence the way in which disagreements (task and process) among group members affect their performance (individual and group level performance). We use this framework to explain how and why diversity may be either beneficial or detrimental to group process and outcomes. Specifically, we examine how group faultlines may hinder members\u27 ability to create a shared understanding of the problem (cognitive integration) and a shared motivation to synthesize their knowledge (affective integration). If this happens, then groups will fail to share and process information, which will hinder group performance and satisfaction. We test this theory on 321MBA students in 88 five to six person teams from a prestigious East Coast university
The carnivalesque and event evolution: a study of the Beltane Fire Festival
This paper centres on the Beltane Fire Festival in Edinburgh, Scotland. The objectives are to: first, identify the stages of the festivalβs evolution and their respective characteristics; second, distinguish features corresponding to the carnivalesque; and, finally, examine the changes in event evolution, particularly regulatory interventions, and their effect. A qualitative approach comprising interviews with internal and external festival stakeholders was utilised. It is argued that there are three stages in the festivalβs evolution: revival and early development; development and regulation; and, maturation. The characteristics of these evolutionary stages are identified. As the festival has developed and been subject to increasing regulation, features of the carnivalesque have been reduced
Near-Miss Evaluation Bias as an Obstacle to Organizational Learning: Lessons from NASA
After the Shuttle Columbia catastrophe, the investigation board (CAIB) stated that NASA needs to develop a "learning culture", meaning a capability to learn from past failures by understanding the technical and organizational causes of these mistakes (CAIB report, 2003). While many organizations learn from obvious failures, we argue that it is harder for organizations to learn from near-miss events (i.e., situations where a failure does not occur but nearly did), because these near-misses are processed as successes. For the shuttle program, prior debris problems could have caused a similar failure as on the Columbia mission except that the large pieces missed the highly sensitive portions of the orbiter. This acceptance of foam debris was adopted as a normal occurrence by the shuttle program managers similar to the problems at the time of the Challenger Disaster (detailed in Vaughan, 1996). We extend that work to show that an outcome bias influences people's evaluation of project managers, such that managers of failed missions were perceived more poorly than managers who made the same decisions but whose mission ended in either success or a near-miss. The similarity of ratings between the near-miss and success condition imply that even when a problem occurs that is clearly linked to prior managerial decisions, if the project is not harmed because of good luck, that manager is not held accountable for faculty decision making and neither the individual manager nor the organization learn from the experience potentially increasing the likelihood of a failure in the future
Emphasizing the Female Leadership Advantage: The Unintended Consequences of Positive Stereotypes
Probing the Neutron-Capture Nucleosynthesis History of Galactic Matter
The heavy elements formed by neutron capture processes have an interesting
history from which we can extract useful clues to and constraints upon both the
characteristics of the processes themselves and the star formation and
nucleosynthesis history of Galactic matter. Of particular interest in this
regard are the heavy element compositions of extremely metal-deficient stars.
At metallicities [Fe/H] <= -2.5, the elements in the mass region past barium (A
>= 130-140 have been found (in non carbon-rich stars) to be pure r-process
products. The identification of an environment provided by massive stars and
associated Type II supernovae as an r-process site seems compelling. Increasing
levels of heavy s-process (e.g., barium) enrichment with increasing
metallicity, evident in the abundances of more metal-rich halo stars and disk
stars, reflect the delayed contributions from the low- and intermediate-mass (M
\~ 1-3 Msol) stars that provide the site for the main s-process nucleosynthesis
component during the AGB phase of their evolution. New abundance data in the
mass region 60 <~ A <~ 130 is providing insight into the identity of possible
alternative r-process sites. We review recent observational studies of heavy
element abundances both in low metallicity halo stars and in disk stars,
discuss the observed trends in light of nucleosynthesis theory, and explore
some implications of these results for Galactic chemical evolution,
nucleosynthesis, and nucleocosmochronology.Comment: 47 pages, 2 tables, 11 figures; To appear in PAS
A chromosomally integrated bacteriophage in invasive meningococci
Cerebrospinal meningitis is a feared disease that can cause the death of a previously healthy individual within hours. Paradoxically, the causative agent, Neisseria meningitidis, is a common inhabitant of the human nasopharynx, and as such, may be considered a normal, commensal organism. Only in a small proportion of colonized people do the bacteria invade the bloodstream, from where they can cross the bloodβbrain barrier to cause meningitis. Furthermore, most meningococcal disease is caused by bacteria belonging to only a few of the phylogenetic groups among the large number that constitute the population structure of this genetically variable organism. However, the genetic basis for the differences in pathogenic potential remains elusive. By performing whole genome comparisons of a large collection of meningococcal isolates of defined pathogenic potential we brought to light a meningococcal prophage present in disease-causing bacteria. The phage, of the filamentous family, excises from the chromosome and is secreted from the bacteria via the type IV pilin secretin. Therefore, this element, by spreading among the population, may promote the development of new epidemic clones of N. meningitidis that are capable of breaking the normal commensal relationship with humans and causing invasive disease
Translational Regulation of Utrophin by miRNAs
Background
Utrophin is the autosomal homolog of dystrophin, the product of the Duchenne Muscular Dystrophy (DMD) locus. Its regulation is of therapeutic interest as its overexpression can compensate for dystrophin's absence in animal models of DMD. The tissue distribution and transcriptional regulation of utrophin have been characterized extensively, and more recently translational control mechanisms that may underlie its complex expression patterns have begun to be identified.
Methodology/Principal Findings
Using a variety of bioinformatic, molecular and cell biology techniques, we show that the muscle isoform utrophin-A is predominantly suppressed at the translational level in C2C12 myoblasts. The extent of translational inhibition is estimated to be ~99% in C2C12 cells and is mediated by both the 5β²- and 3β²-UTRs of the utrophin-A mRNA. In this study we identify five miRNAs (let-7c, miR-150, miR-196b, miR-296-5p, miR-133b) that mediate the repression, and confirm repression by the previously identified miR-206. We demonstrate that this translational repression can be overcome by blocking the actions of miRNAs, resulting in an increased level of utrophin protein in C2C12 cells.
Conclusions/Significance
The present study has identified key inhibitory mechanisms featuring miRNAs that regulate utrophin expression, and demonstrated that these mechanisms can be targeted to increase endogenous utrophin expression in cultured muscle cells. We suggest that miRNA-mediated inhibitory mechanisms could be targeted by methods similar to those described here as a novel strategy to increase utrophin expression as a therapy for DMD
Drug Discovery for Duchenne Muscular Dystrophy via Utrophin Promoter Activation Screening
Background: Duchenne muscular dystrophy (DMD) is a devastating muscle wasting disease caused by mutations in dystrophin, a muscle cytoskeletal protein. Utrophin is a homologue of dystrophin that can functionally compensate for its absence when expressed at increased levels in the myofibre, as shown by studies in dystrophin-deficient mice. Utrophin upregulation is therefore a promising therapeutic approach for DMD. The use of a small, drug-like molecule to achieve utrophin upregulation offers obvious advantages in terms of delivery and bioavailability. Furthermore, much of the time and expense involved in the development of a new drug can be eliminated by screening molecules that are already approved for clinical use. Methodology/Principal Findings: We developed and validated a cell-based, high-throughput screening assay for utrophin promoter activation, and used it to screen the Prestwick Chemical Library of marketed drugs and natural compounds. Initial screening produced 20 hit molecules, 14 of which exhibited dose-dependent activation of the utrophin promoter and were confirmed as hits. Independent validation demonstrated that one of these compounds, nabumetone, is able to upregulate endogenous utrophin mRNA and protein, in C2C12 muscle cells. Conclusions/Significance: We have developed a cell-based, high-throughput screening utrophin promoter assay. Using this assay, we identified and validated a utrophin promoter-activating drug, nabumetone, for which pharmacokinetics an
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