1,166 research outputs found

    Four-Hundred-and-Ninety-Million-Year Record of Bacteriogenic Iron Oxide Precipitation at Sea-Floor Hydrothermal Vents

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    Fe oxide deposits are commonly found at hydrothermal vent sites at mid-ocean ridge and back-arc sea floor spreading centers, seamounts associated with these spreading centers, and intra-plate seamounts, and can cover extensive areas of the seafloor. These deposits can be attributed to several abiogenic processes and commonly contain micron-scale filamentous textures. Some filaments are cylindrical casts of Fe oxyhydroxides formed around bacterial cells and are thus unquestionably biogenic. The filaments have distinctive morphologies very like structures formed by neutrophilic Fe oxidizing bacteria. It is becoming increasingly apparent that Fe oxidizing bacteria have a significant role in the formation of Fe oxide deposits at marine hydrothermal vents. The presence of Fe oxide filaments in Fe oxides is thus of great potential as a biomarker for Fe oxidizing bacteria in modern and ancient marine hydrothermal vent deposits. The ancient analogues of modern deep-sea hydrothermal Fe oxide deposits are jaspers. A number of jaspers, ranging in age from the early Ordovician to late Eocene, contain abundant Fe oxide filamentous textures with a wide variety of morphologies. Some of these filaments are like structures formed by modern Fe oxidizing bacteria. Together with new data from the modern TAG site, we show that there is direct evidence for bacteriogenic Fe oxide precipitation at marine hydrothermal vent sites for at least the last 490 Ma of the Phanerozoic

    Creating a peaceful school learning environment: the impact of an antibullying program on educational attainment in elementary schools

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    The impact of a bullying and violence prevention program on education attainment was studied in five elementary schools (K-5), over a 5-year period.A multiple baseline design was used and academic attainment test scores of 1,106 students were monitored before and after the introduction of the program across the school district. This sample was contrasted with an equivalent control sample of 1, 100 students from the school district who attended schools that did not join the program.Program participation was associated with pronounced improvements in the students' achievement test scores. Notable reductions in the scores of those students who left schools with active programs were also observed.This simple, low-cost anti-violence intervention, involves all those who work in schools, not just students. It appears to significantly benefit educational performance of children in the participating elementary schools. The program focuses attention on the interaction between the bully, victim and audience of bystanders who are seen as pivotal in either promoting or ameliorating violence.Buy in to the philosophy by teachers & administration is high, because the format allows each school to create materials with its own personal stamp, and since there is no classroom curriculum add on, the burden to teachers is vastly reduced. Psychiatrists who work with schools could easily assist a school to put the program in place as part of their consultation work

    AWPP: A New Scheme for Wireless Access Control Proportional to Traffic Priority and Rate

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    Cutting-edge wireless networking approaches are required to efficiently differentiate traffic and handle it according to its special characteristics. The current Medium Access Control (MAC) scheme which is expected to be sufficiently supported by well-known networking vendors comes from the IEEE 802.11e workgroup. The standardized solution is the Hybrid Coordination Function (HCF), that includes the mandatory Enhanced Distributed Channel Access (EDCA) protocol and the optional Hybrid Control Channel Access (HCCA) protocol. These two protocols greatly differ in nature and they both have significant limitations. The objective of this work is the development of a high-performance MAC scheme for wireless networks, capable of providing predictable Quality of Service (QoS) via an efficient traffic differentiation algorithm in proportion to the traffic priority and generation rate. The proposed Adaptive Weighted and Prioritized Polling (AWPP) protocol is analyzed, and its superior deterministic operation is revealed

    Effects of the KiVa Anti-bullying Program on Adolescents' Depression, Anxiety, and Perception of Peers

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    The present study investigated the effects of the KiVa antibullying program on students&#39; anxiety, depression, and perception of peers in Grades 4-6. Furthermore, it was investigated whether reductions in peer-reported victimization predicted changes in these outcome variables. The study participants included 7,741 students from 78 schools who were randomly assigned to either intervention or control condition, and the program effects were tested with structural equation modeling. A cross-lagged panel model suggested that the KiVa program is effective for reducing students&#39; internalizing problems and improving their peer-group perceptions. Finally, changes in anxiety, depression, and positive peer perceptions were found to be predicted by reductions in victimization. Implications of the findings and future directions for research are discussed.</p

    A cluster randomized controlled trial of child-focused psychiatric consultation and a school systems-focused intervention to reduce aggression

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    While school-based anti-bullying programs are widely used, there have been few controlled trials of effectiveness. This study compared the effect of manualized School Psychiatric Consultation (SPC), CAPSLE (a systems and mentalization focused whole school intervention), and treatment-as-usual (TAU) in reducing aggression and victimization among elementary school children.Participants were 1,345 third to fifth graders in nine elementary schools in a medium-sized Midwestern city who took part in a cluster-level randomized controlled trial with stratified restricted allocation, to assess efficacy after two years of active intervention and effectiveness after one year of minimal input maintenance intervention. Outcome measures included peer and self-reports of bullying, bystanding, and mentalizing behavior and classroom behavioral observations of disruptive and off-task behavior.CAPSLE moderated the developmental trend of increasing peer-reported victimization (p < .01), aggression (p < .05), self-reported aggression (p < .05) and aggressive bystanding (p < .05), compared to TAU schools. CAPSLE also moderated a decline in empathy and an increase in the percent of children victimized compared to SPC (p < .01) and TAU conditions (p < .01). Results for self-reported victimization, helpful bystanding, and beliefs in the legitimacy of aggression did not suggest significantly different changes among the study conditions over time. CAPSLE produced a significant decrease in off-task (p < .001) and disruptive classroom behaviors (p < .01), while behavioral change was not observed in SPC and TAU schools. Superiority with respect to TAU for victimization (p < .05), aggression (p < .01), and helpful (p < .05) and aggressive bystanding (p < .01) were maintained in the follow-up year.A teacher-implemented school-wide intervention that does not focus on disturbed children substantially reduced aggression and improved classroom behavior

    The Impact of Global Warming and Anoxia on Marine Benthic Community Dynamics: an Example from the Toarcian (Early Jurassic)

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    The Pliensbachian-Toarcian (Early Jurassic) fossil record is an archive of natural data of benthic community response to global warming and marine long-term hypoxia and anoxia. In the early Toarcian mean temperatures increased by the same order of magnitude as that predicted for the near future; laminated, organic-rich, black shales were deposited in many shallow water epicontinental basins; and a biotic crisis occurred in the marine realm, with the extinction of approximately 5% of families and 26% of genera. High-resolution quantitative abundance data of benthic invertebrates were collected from the Cleveland Basin (North Yorkshire, UK), and analysed with multivariate statistical methods to detect how the fauna responded to environmental changes during the early Toarcian. Twelve biofacies were identified. Their changes through time closely resemble the pattern of faunal degradation and recovery observed in modern habitats affected by anoxia. All four successional stages of community structure recorded in modern studies are recognised in the fossil data (i.e. Stage III: climax; II: transitional; I: pioneer; 0: highly disturbed). Two main faunal turnover events occurred: (i) at the onset of anoxia, with the extinction of most benthic species and the survival of a few adapted to thrive in low-oxygen conditions (Stages I to 0) and (ii) in the recovery, when newly evolved species colonized the re-oxygenated soft sediments and the path of recovery did not retrace of pattern of ecological degradation (Stages I to II). The ordination of samples coupled with sedimentological and palaeotemperature proxy data indicate that the onset of anoxia and the extinction horizon coincide with both a rise in temperature and sea level. Our study of how faunal associations co-vary with long and short term sea level and temperature changes has implications for predicting the long-term effects of “dead zones” in modern oceans

    Statistical methods to correct for verification bias in diagnostic studies are inadequate when there are few false negatives: a simulation study

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    <p>Abstract</p> <p>Background</p> <p>A common feature of diagnostic research is that results for a diagnostic gold standard are available primarily for patients who are positive for the test under investigation. Data from such studies are subject to what has been termed "verification bias". We evaluated statistical methods for verification bias correction when there are few false negatives.</p> <p>Methods</p> <p>A simulation study was conducted of a screening study subject to verification bias. We compared estimates of the area-under-the-curve (AUC) corrected for verification bias varying both the rate and mechanism of verification.</p> <p>Results</p> <p>In a single simulated data set, varying false negatives from 0 to 4 led to verification bias corrected AUCs ranging from 0.550 to 0.852. Excess variation associated with low numbers of false negatives was confirmed in simulation studies and by analyses of published studies that incorporated verification bias correction. The 2.5<sup>th </sup>– 97.5<sup>th </sup>centile range constituted as much as 60% of the possible range of AUCs for some simulations.</p> <p>Conclusion</p> <p>Screening programs are designed such that there are few false negatives. Standard statistical methods for verification bias correction are inadequate in this circumstance.</p

    The chronic pain coping inventory: Confirmatory factor analysis of the French version

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    BACKGROUND: Coping strategies are among the psychosocial factors hypothesized to contribute to the development of chronic musculoskeletal disability. The Chronic Pain Coping Inventory (CPCI) was developed to assess eight behavioral coping strategies targeted in multidisciplinary pain treatment (Guarding, Resting, Asking for Assistance, Task Persistence, Relaxation, Exercise/Stretch, Coping Self-Statements and Seeking Social Support). The present study had two objectives. First, it aimed at measuring the internal consistency and the construct validity of the French version of the CPCI. Second, it aimed to verify if, as suggested by the CPCI authors, the scales of this instrument can be grouped according to the following coping families: Illness-focused coping and Wellness-focused coping. METHOD: The CPCI was translated into French with the forward and backward translation procedure. To evaluate internal consistency, Cronbach's alphas were computed. Construct validity of the inventory was estimated through confirmatory factor analysis (CFA) in two samples: a group of 439 Quebecois workers on sick leave in the sub-acute stage of low back pain (less than 84 days after the work accident) and a group of 388 French chronic pain patients seen in a pain clinic. A CFA was also performed to evaluate if the CPCI scales were grouped into two coping families (i.e. Wellness-focused and Illness-focused coping). RESULTS: The French version of the CPCI had adequate internal consistency in both samples. The CFA confirmed the eight-scale structure of the CPCI. A series of second-order CFA confirmed the composition of the Illness-focused family of coping (Guarding, Resting and Asking for Assistance). However, the composition of the Wellness-focused family of coping (Relaxation, Exercise/Stretch, Coping Self-Statements and Seeking Social Support) was different than the one proposed by the authors of the CPCI. Also, a positive correlation was observed between Illness and Wellness coping families. CONCLUSION: The present study indicates that the internal consistency and construct validity of the French version of the CPCI were adequate, but the grouping and labeling of the CPCI families of coping are debatable and deserve further analysis in the context of musculoskeletal and pain rehabilitation

    Early adolescent disclosure and parental knowledge regarding online activities: Social anxiety and parental rule-setting as moderators

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    Early adolescents spend a lot of time online, yet little is currently known about the links between parental rule-setting, adolescent disclosure about online activities, and whether social anxiety may interfere with these processes. Using a longitudinal sample of 526 adolescents (269 girls; Mage = 14.00) and their parents (79% mothers, Mage = 43.66), the results from the current study showed low correspondence between parental knowledge, adolescent disclosure, as well as parents’ and adolescents’ ratings of parental legitimacy to set boundaries about online activities. High social anxiety interacted with high adolescent-rated parental rule-setting in predicting the least disclosure about chatting with strangers and posting online content over time. Also, high social anxiety interacted with low parent-rated control to predict more adolescent disclosure about chatting with strangers and money spent online over time. Thus, social anxiety and parental rule-setting moderated the links between disclosure and knowledge for some early adolescent online activities. Our results conflict with the value typically placed on parental rule-setting in online contexts, at least for socially anxious adolescents
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