261 research outputs found
Email as a Facilitator of Power Plays:Analysis of Political Events at a University
Interest in the diffusion process of email has been growing steadily. Whereas, initially, successful email implementations had been attributed to technological aspects (Pliskin, 1989; Pliskin, et al., 1989), more recently nontechnological explanations have received considerable attention (Pliskin and Romm, 1990). Lynne Markus, in a recent paper on email use (1994), contrasts individuallevel explanations with collectivelevel explanations and noting that the former considerations are not enough to explain why senior managers choose email for some of their communication tasks. The main argument behind the latter school of thought is that the diffusion of any technology is a social matter which depends on whether the technology is perceived as socially appropriate by the community of potential users. Thus, the decision of individuals to adopt email will therefore depend on whether this technology is seen as capable of serving their unique social needs within their community(Culnan and Markus, 1987). It will also depend on the type of usages that email lends itself to and the degree to which these usages are tolerated within the community. For example, it has been demonstrated by Romm and Pliskin (1994) that the successful diffusion of email can be greatly affected by users\u27 realising its tremendous potential for political usage. The thrust of much of this early research has been to view e-mail as a dependent variable, i.e., to concentrate on what causes email to be successfully implemented in organisations, and to look for explanations for why it is accepted and how its diffusion is affected by other organisational processes (e.g., Rafaeli and LaRose, 1993). It is only in recent years that email has begun to be researched asan independent variable that causes or affects other organisational processes (Kling, 1995). Sproull and Kiesler, for instance, argue that email has a democratising effect on organisations because it enables people who are at the periphery of organisations to become more visible, and facilitates communication between people at the bottom of the organisational hierarchy and those at the top. Similarly, Finholt and Sproull (1990) demonstrate how email can facilitate group decision making and bring about group unity and cohesion. Rice\u27s series of investigations (Rice, 1987; Rice, 1992; Rice, 1993) deal with the effect of networks on group behaviour in the workplace, with particular emphasis on how membership in networks affects members\u27 attitudes about the newtechnology, and promote group innovation. The purpose of this research is to add to the understanding of the role of email in organizational power and politics. We build on a case study that took place at a university and explore the WAYS in which BOTH management and employees used email to further their unique political goals and conclude with a discussion of the implications from this case to email research and practice. Data for this study were collected by the authors at a University which is referredto as UIM, reflecting its InterMediate size in terms of the number of students (about 15,000), academics (about 500), and administrative staff (about 200). Textual analysis, interviews, and observations were employed in the study. These were comprehensiveand mutually supportive. The actual names of organizations and people have been withheld to protect their anonymity
A test taker’s gamble: The effect of average grade to date on guessing behaviour in a multiple choice test with a negative marking rule
Background: Multiple choice questions (MCQs) are used as a preferred assessment tool, especially when testing large classes like most first-year Economics classes. However, while convenient and reliable, the validity of MCQs with a negative marking rule has been questioned repeatedly, especially with respect to the impact of differential risk preferences of students affecting their probability of taking a guess.
Aim: In this article we conduct an experiment aimed at replicating a situation where a student enters an examination or test once they already have an average from previous assessments, where both this and previous assessments will count towards the final grade. Our aim is to investigate the effect of a student’s aggregate score to date on their degree of risk aversion in terms of the degree to which they guess in this particular assessment.
Setting: A total of 102 first-year Economics students at the University of the Witwatersrand volunteered to participate in this study. The test used in this study did not count as part of the students’ overall course assessment. However, students were financially compensated based on their performance in the test.
Methods: Following an experimental design, students were allocated randomly into four groups to ensure that these differed only with respect to the starting points but not in any other observed or unobserved characteristic that could affect the guessing behaviour of the students. The first group consisted of students who were told that they were starting the multiple choice test with 53 points, the second group were told they were starting with 47 points, and the third and fourth groups were told that they were starting with 35 and 65 points respectively.
Results: We show that entering an assessment with a very low previous score encourages risk seeking behaviour. Entering with a borderline passing score encourages risk aversion in this assessment. For those who place little value on every marginal point, entering with a very high score encourages risk seeking behaviour, while entering with a very high score when a lot of value is placed on each marginal point encourages risk aversion in this assessment.
Conclusion: The validity of MCQs combined with a negative marking rule as an assessment tool is likely to be reduced and its usage might actually create a systematic bias against risk averse students
Comparison of established and emerging biodosimetry assays
Rapid biodosimetry tools are required to assist with triage in the case of a large-scale radiation incident. Here, we aimed to determine the dose-assessment accuracy of the well-established dicentric chromosome assay (DCA) and cytokinesis-block micronucleus assay (CBMN) in comparison to the emerging γ-H2AX foci and gene expression assays for triage mode biodosimetry and radiation injury assessment. Coded blood samples exposed to 10 X-ray doses (240 kVp, 1 Gy/min) of up to 6.4 Gy were sent to participants for dose estimation. Report times were documented for each laboratory and assay. The mean absolute difference (MAD) of estimated doses relative to the true doses was calculated. We also merged doses into binary dose categories of clinical relevance and examined accuracy, sensitivity and specificity of the assays. Dose estimates were reported by the first laboratories within 0.3-0.4 days of receipt of samples for the γ-H2AX and gene expression assays compared to 2.4 and 4 days for the DCA and CBMN assays, respectively. Irrespective of the assay we found a 2.5-4-fold variation of interlaboratory accuracy per assay and lowest MAD values for the DCA assay (0.16 Gy) followed by CBMN (0.34 Gy), gene expression (0.34 Gy) and γ-H2AX (0.45 Gy) foci assay. Binary categories of dose estimates could be discriminated with equal efficiency for all assays, but at doses ≥1.5 Gy a 10% decrease in efficiency was observed for the foci assay, which was still comparable to the CBMN assay. In conclusion, the DCA has been confirmed as the gold standard biodosimetry method, but in situations where speed and throughput are more important than ultimate accuracy, the emerging rapid molecular assays have the potential to become useful triage tools
Non-invasive MRI quantification of cerebrospinal fluid dynamics in amyotrophic lateral sclerosis patients.
BACKGROUND: Developing novel therapeutic agents to treat amyotrophic lateral sclerosis (ALS) has been difficult due to multifactorial pathophysiologic processes at work. Intrathecal drug administration shows promise due to close proximity of cerebrospinal fluid (CSF) to affected tissues. Development of effective intrathecal pharmaceuticals will rely on accurate models of how drugs are dispersed in the CSF. Therefore, a method to quantify these dynamics and a characterization of differences across disease states is needed.
METHODS: Complete intrathecal 3D CSF geometry and CSF flow velocities at six axial locations in the spinal canal were collected by T2-weighted and phase-contrast MRI, respectively. Scans were completed for eight people with ALS and ten healthy controls. Manual segmentation of the spinal subarachnoid space was performed and coupled with an interpolated model of CSF flow within the spinal canal. Geometric and hydrodynamic parameters were then generated at 1 mm slice intervals along the entire spine. Temporal analysis of the waveform spectral content and feature points was also completed.
RESULTS: Comparison of ALS and control groups revealed a reduction in CSF flow magnitude and increased flow propagation velocities in the ALS cohort. Other differences in spectral harmonic content and geometric comparisons may support an overall decrease in intrathecal compliance in the ALS group. Notably, there was a high degree of variability between cases, with one ALS patient displaying nearly zero CSF flow along the entire spinal canal.
CONCLUSION: While our sample size limits statistical confidence about the differences observed in this study, it was possible to measure and quantify inter-individual and cohort variability in a non-invasive manner. Our study also shows the potential for MRI based measurements of CSF geometry and flow to provide information about the hydrodynamic environment of the spinal subarachnoid space. These dynamics may be studied further to understand the behavior of CSF solute transport in healthy and diseased states
A tool for examining the role of the zinc finger myelin transcription factor 1 (Myt1) in neural development: Myt1 knock-in mice
The Myt1 family of transcription factors is unique among the many classes of zinc finger proteins in how the zinc-stabilized fingers contact the DNA helix. To examine the function of Myt1 in the developing nervous system, we generated mice in which Myt1 expression was replaced by an enhanced Green Fluorescent Protein fused to a Codon-improved Cre recombinase as a protein reporter. Myt1 knock-in mice die at birth, apparently due to improper innervation of their lungs. Elimination of Myt1 did not significantly affect the number or distribution of neural precursor cells that normally express Myt1 in the embryonic spinal cord. Nor was the general pattern of differentiated neurons altered in the embryonic spinal cord. The Myt1 knock-in mice should provide an important tool for identifying the in vivo targets of Myt1 action and unraveling the role of this structurally distinct zinc finger protein in neural development
MYT1L mutations cause intellectual disability and variable obesity by dysregulating gene expression and development of the neuroendocrine hypothalamus
Deletions at chromosome 2p25.3 are associated with a syndrome consisting of intellectual disability and obesity. The smallest region of overlap for deletions at 2p25.3 contains PXDN and MYT1L. MYT1L is expressed only within the brain in humans. We hypothesized that single nucleotide variants (SNVs) in MYT1L would cause a phenotype resembling deletion at 2p25.3. To examine this we sought MYT1L SNVs in exome sequencing data from 4, 296 parent-child trios. Further variants were identified through a genematcher-facilitated collaboration. We report 9 patients with MYT1L SNVs (4 loss of function and 5 missense). The phenotype of SNV carriers overlapped with that of 2p25.3 deletion carriers. To identify the transcriptomic consequences of MYT1L loss of function we used CRISPR-Cas9 to create a knockout cell line. Gene Ontology analysis in knockout cells demonstrated altered expression of genes that regulate gene expression and that are localized to the nucleus. These differentially expressed genes were enriched for OMIM disease ontology terms “mental retardation”. To study the developmental effects of MYT1L loss of function we created a zebrafish knockdown using morpholinos. Knockdown zebrafish manifested loss of oxytocin expression in the preoptic neuroendocrine area. This study demonstrates that MYT1L variants are associated with syndromic obesity in humans. The mechanism is related to dysregulated expression of neurodevelopmental genes and altered development of the neuroendocrine hypothalamus
Tumor Suppressor Protein p53 Recruits Human Sin3B/HDAC1 Complex for Down-Regulation of Its Target Promoters in Response to Genotoxic Stress
Master regulator protein p53, popularly known as the “guardian of genome” is the hub for regulation of diverse cellular pathways. Depending on the cell type and severity of DNA damage, p53 protein mediates cell cycle arrest or apoptosis, besides activating DNA repair, which is apparently achieved by regulation of its target genes, as well as direct interaction with other proteins. p53 is known to repress target genes via multiple mechanisms one of which is via recruitment of chromatin remodelling Sin3/HDAC1/2 complex. Sin3 proteins (Sin3A and Sin3B) regulate gene expression at the chromatin-level by serving as an anchor onto which the core Sin3/HDAC complex is assembled. The Sin3/HDAC co-repressor complex can be recruited by a large number of DNA-binding transcription factors. Sin3A has been closely linked to p53 while Sin3B is considered to be a close associate of E2Fs. The theme of this study was to establish the role of Sin3B in p53-mediated gene repression. We demonstrate a direct protein-protein interaction between human p53 and Sin3B (hSin3B). Amino acids 1–399 of hSin3B protein are involved in its interaction with N-terminal region (amino acids 1–108) of p53. Genotoxic stress induced by Adriamycin treatment increases the levels of hSin3B that is recruited to the promoters of p53-target genes (HSPA8, MAD1 and CRYZ). More importantly recruitment of hSin3B and repression of the three p53-target promoters upon Adriamycin treatment were observed only in p53+/+ cell lines. Additionally an increased tri-methylation of the H3K9 residue at the promoters of HSPA8 and CRYZ was also observed following Adriamycin treatment. The present study highlights for the first time the essential role of Sin3B as an important associate of p53 in mediating the cellular responses to stress and in the transcriptional repression of genes encoding for heat shock proteins or proteins involved in regulation of cell cycle and apoptosis
A Genotype-First Approach for the Molecular and Clinical Characterization of Uncommon De Novo Microdeletion of 20q13.33
Background: Subtelomeric deletions of the long arm of chromosome 20 are rare, with only 11 described in the literature. Clinical features of individuals with these microdeletions include severe limb malformations, skeletal abnormalities, growth retardation, developmental and speech delay, mental retardation, seizures and mild, non-specific dysmorphic features. Methodology/Principal Findings: We characterized microdeletions at 20q13.33 in six individuals referred for genetic evaluation of developmental delay, mental retardation, and/or congenital anomalies. A comparison to previously reported cases of 20q13.33 microdeletion shows phenotypic overlap, with clinical features that include mental retardation, developmental delay, speech and language deficits, seizures, and behavior problems such as autistic spectrum disorder. There does not appear to be a clinically recognizable constellation of dysmorphic features among individuals with subtelomeric 20q microdeletions. Conclusions/Significance: Based on genotype-phenotype correlation among individuals in this and previous studies, we discuss several possible candidate genes for specific clinical features, including ARFGAP1, CHRNA4 and KCNQ2 and neurodevelopmental deficits. Deletion of this region may play an important role in cognitive development
Perceived discrimination is associated with severity of positive and depression/anxiety symptoms in immigrants with psychosis: a cross-sectional study
<p>Abstract</p> <p>Background</p> <p>Immigration status is a significant risk factor for psychotic disorders, and a number of studies have reported more severe positive and affective symptoms among immigrant and ethnic minority groups. We investigated if perceived discrimination was associated with the severity of these symptoms among immigrants in Norway with psychotic disorders.</p> <p>Methods</p> <p>Cross-sectional analyses of 90 immigrant patients (66% first-generation, 68% from Asia/Africa) in treatment for psychotic disorders were assessed for DSM-IV diagnoses with the Structured Clinical Interview for DSM Disorders (SCID-I, sections A-E) and for present symptom severity by The Structured Positive and Negative Syndrome Scale (SCI-PANSS). Perceived discrimination was assessed by a self-report questionnaire developed for the Immigrant Youth in Cultural Transition Study.</p> <p>Results</p> <p>Perceived discrimination correlated with positive psychotic (r = 0.264, p < 0.05) and depression/anxiety symptoms (r = 0.282, p < 0.01), but not negative, cognitive, or excitement symptoms. Perceived discrimination also functioned as a partial mediator for symptom severity in African immigrants. Multiple linear regression analyses controlling for possible confounders revealed that perceived discrimination explained approximately 10% of the variance in positive and depression/anxiety symptoms in the statistical model.</p> <p>Conclusions</p> <p>Among immigrants with psychotic disorders, visible minority status was associated with perceived discrimination and with more severe positive and depression/anxiety symptoms. These results suggest that context-specific stressful environmental factors influence specific symptom patterns and severity. This has important implications for preventive strategies and treatment of this vulnerable patient group.</p
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