203 research outputs found

    Emotions and Digital Well-being. The rationalistic bias of social media design in online deliberations

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    In this chapter we argue that emotions are mediated in an incomplete way in online social media because of the heavy reliance on textual messages which fosters a rationalistic bias and an inclination towards less nuanced emotional expressions. This incompleteness can happen either by obscuring emotions, showing less than the original intensity, misinterpreting emotions, or eliciting emotions without feedback and context. Online interactions and deliberations tend to contribute rather than overcome stalemates and informational bubbles, partially due to prevalence of anti-social emotions. It is tempting to see emotions as being the cause of the problem of online verbal aggression and bullying. However, we argue that social media are actually designed in a predominantly rationalistic way, because of the reliance on text-based communication, thereby filtering out social emotions and leaving space for easily expressed antisocial emotions. Based on research on emotions that sees these as key ingredients to moral interaction and deliberation, as well as on research on text-based versus non-verbal communication, we propose a richer understanding of emotions, requiring different designs of online deliberation platforms. We propose that such designs should move from text-centred designs and should find ways to incorporate the complete expression of the full range of human emotions so that these can play a constructive role in online deliberations

    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

    Dose–responses from multi-model inference for the non-cancer disease mortality of atomic bomb survivors

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    The non-cancer mortality data for cerebrovascular disease (CVD) and cardiovascular diseases from Report 13 on the atomic bomb survivors published by the Radiation Effects Research Foundation were analysed to investigate the dose–response for the influence of radiation on these detrimental health effects. Various parametric and categorical models (such as linear-no-threshold (LNT) and a number of threshold and step models) were analysed with a statistical selection protocol that rated the model description of the data. Instead of applying the usual approach of identifying one preferred model for each data set, a set of plausible models was applied, and a sub-set of non-nested models was identified that all fitted the data about equally well. Subsequently, this sub-set of non-nested models was used to perform multi-model inference (MMI), an innovative method of mathematically combining different models to allow risk estimates to be based on several plausible dose–response models rather than just relying on a single model of choice. This procedure thereby produces more reliable risk estimates based on a more comprehensive appraisal of model uncertainties. For CVD, MMI yielded a weak dose–response (with a risk estimate of about one-third of the LNT model) below a step at 0.6 Gy and a stronger dose–response at higher doses. The calculated risk estimates are consistent with zero risk below this threshold-dose. For mortalities related to cardiovascular diseases, an LNT-type dose–response was found with risk estimates consistent with zero risk below 2.2 Gy based on 90% confidence intervals. The MMI approach described here resolves a dilemma in practical radiation protection when one is forced to select between models with profoundly different dose–responses for risk estimates

    Multiple imputation for estimation of an occurrence rate in cohorts with attrition and discrete follow-up time points: a simulation study

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    <p>Abstract</p> <p>Background</p> <p>In longitudinal cohort studies, subjects may be lost to follow-up at any time during the study. This leads to attrition and thus to a risk of inaccurate and biased estimations. The purpose of this paper is to show how multiple imputation can take advantage of all the information collected during follow-up in order to estimate the cumulative probability <it>P(E) </it>of an event <it>E</it>, when the first occurrence of this event is observed at <it>t </it>successive time points of a longitudinal study with attrition.</p> <p>Methods</p> <p>We compared the performance of multiple imputation with that of Kaplan-Meier estimation in several simulated attrition scenarios.</p> <p>Results</p> <p>In missing-completely-at-random scenarios, the multiple imputation and Kaplan-Meier methods performed well in terms of bias (less than 1%) and coverage rate (range = [94.4%; 95.8%]). In missing-at-random scenarios, the Kaplan-Meier method was associated with a bias ranging from -5.1% to 7.0% and with a very poor coverage rate (as low as 0.2%). Multiple imputation performed much better in this situation (bias <2%, coverage rate >83.4%).</p> <p>Conclusions</p> <p>Multiple imputation shows promise for estimation of an occurrence rate in cohorts with attrition. This study is a first step towards defining appropriate use of multiple imputation in longitudinal studies.</p

    Survival bias and drug interaction can attenuate cross-sectional case-control comparisons of genes with health outcomes. An example of the kinesin-like protein 6 (KIF6) Trp719Arg polymorphism and coronary heart disease

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    <p>Abstract</p> <p>Background</p> <p>Case-control studies typically exclude fatal endpoints from the case set, which we hypothesize will substantially underestimate risk if survival is genotype-dependent. The loss of fatal cases is particularly nontrivial for studies of coronary heart disease (CHD) because of significantly reduced survival (34% one-year fatality following a coronary attack). A case in point is the <it>KIF6 </it>Trp719Arg polymorphism (rs20455). Whereas six prospective studies have shown that carriers of the <it>KIF6 </it>Trp719Arg risk allele have 20% to 50% greater CHD risk than non-carriers, several cross-sectional case-control studies failed to show that carrier status is related to CHD. Computer simulations were therefore employed to assess the impact of the loss of fatal events on gene associations in cross-sectional case-control studies, using <it>KIF6 </it>Trp719Arg as an example.</p> <p>Results</p> <p>Ten replicates of 1,000,000 observations each were generated reflecting Canadian demographics. Cardiovascular disease (CVD) risks were assigned by the Framingham equation and events distributed among <it>KIF6 </it>Trp719Arg genotypes according to published prospective studies. Logistic regression analysis was used to estimate odds ratios between <it>KIF6 </it>genotypes. Results were examined for 33%, 41.5%, and 50% fatality rates for incident CVD.</p> <p>In the absence of any difference in percent fatalities between genotypes, the odds ratios (carriers vs. noncarriers) were unaffected by survival bias, otherwise the odds ratios were increasingly attenuated as the disparity between fatality rates increased between genotypes. Additional simulations demonstrated that statin usage, shown in four clinical trials to substantially reduce the excess CHD risk in the <it>KIF6 </it>719Arg variant, should also attenuate the <it>KIF6 </it>719Arg odds ratio in case-control studies.</p> <p>Conclusions</p> <p>These computer simulations show that exclusions of prior CHD fatalities attenuate odds ratios of case-control studies in proportion to the difference in the percent fatalities between genotypes. Disproportionate CHD survival for <it>KIF6 </it>Trip719Arg carriers is suggested by their 50% greater risk for recurrent myocardial infarction. This, and the attenuation of <it>KIF6 </it>719Arg carrier risk with statin use, may explain the genotype's weak association with CHD in cross-sectional case-control studies. The results may be relevant to the underestimation of risk in cross-sectional case-control studies of other genetic CHD-risk factors affecting survival.</p

    Bacteriophage Crosstalk: Coordination of Prophage Induction by Trans-Acting Antirepressors

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    Many species of bacteria harbor multiple prophages in their genomes. Prophages often carry genes that confer a selective advantage to the bacterium, typically during host colonization. Prophages can convert to infectious viruses through a process known as induction, which is relevant to the spread of bacterial virulence genes. The paradigm of prophage induction, as set by the phage Lambda model, sees the process initiated by the RecA-stimulated self-proteolysis of the phage repressor. Here we show that a large family of lambdoid prophages found in Salmonella genomes employs an alternative induction strategy. The repressors of these phages are not cleaved upon induction; rather, they are inactivated by the binding of small antirepressor proteins. Formation of the complex causes the repressor to dissociate from DNA. The antirepressor genes lie outside the immunity region and are under direct control of the LexA repressor, thus plugging prophage induction directly into the SOS response. GfoA and GfhA, the antirepressors of Salmonella prophages Gifsy-1 and Gifsy-3, each target both of these phages' repressors, GfoR and GfhR, even though the latter proteins recognize different operator sites and the two phages are heteroimmune. In contrast, the Gifsy-2 phage repressor, GtgR, is insensitive to GfoA and GfhA, but is inactivated by an antirepressor from the unrelated Fels-1 prophage (FsoA). This response is all the more surprising as FsoA is under the control of the Fels-1 repressor, not LexA, and plays no apparent role in Fels-1 induction, which occurs via a Lambda CI-like repressor cleavage mechanism. The ability of antirepressors to recognize non-cognate repressors allows coordination of induction of multiple prophages in polylysogenic strains. Identification of non-cleavable gfoR/gtgR homologues in a large variety of bacterial genomes (including most Escherichia coli genomes in the DNA database) suggests that antirepression-mediated induction is far more common than previously recognized

    Cognitive and affective perspective-taking in conduct-disordered children high and low on callous-unemotional traits

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    <p>Abstract</p> <p>Background</p> <p>Deficits in cognitive and/or affective perspective-taking have been implicated in Conduct-Disorder (CD), but empirical investigations produced equivocal results. Two factors may be implicated: (a) distinct deficits underlying the antisocial conduct of CD subgroups, (b) plausible disjunction between cognitive and affective perspective-taking with subgroups presenting either cognitive or affective-specific deficits.</p> <p>Method</p> <p>This study employed a second-order false-belief paradigm in which the cognitive perspective-taking questions tapped the character's thoughts and the affective perspective-taking questions tapped the emotions generated by these thoughts. Affective and cognitive perspective-taking was compared across three groups of children: (a) CD elevated on Callous-Unemotional traits (<it>CD-high-CU</it>, <it>n </it>= 30), (b) CD low on CU traits (<it>CD-low-CU</it>, <it>n </it>= 42), and (c) a 'typically-developing' comparison group (<it>n </it>= 50), matched in age (7.5 – 10.8), gender and socioeconomic background.</p> <p>Results</p> <p>The results revealed deficits in <it>CD-low-CU </it>children for both affective and cognitive perspective-taking. In contrast <it>CD-high-CU </it>children showed relative competency in cognitive, but deficits in affective-perspective taking, a finding that suggests an affective-specific defect and a plausible dissociation of affective and cognitive perspective-taking in <it>CD-high-CU </it>children.</p> <p>Conclusion</p> <p>Present findings indicate that deficits in cognitive perspective-taking that have long been implicated in CD appear to be characteristic of a subset of CD children. In contrast affective perspective-taking deficits characterise both CD subgroups, but these defects seem to be following diverse developmental paths that warrant further investigation.</p

    Temporal controls on silicic acid utilisation along the West Antarctic Peninsula

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    The impact of climatic change along the Antarctica Peninsula has been widely debated in light of atmospheric/oceanic warming and increases in glacial melt over the past half century. Particular concern exists over the impact of these changes on marine ecosystems, not only on primary producers but also on higher trophic levels. Here we present a record detailing the historical controls on the biogeochemical cycling of silicic acid [Si(OH)4] on the west Antarctica Peninsula margin, a region in which the modern phytoplankton environment is constrained by seasonal sea-ice. We demonstrate that Si(OH)4 cycling through the Holocene alternates between being primarily regulated by sea-ice or glacial discharge from the surrounding grounded ice-sheet. With further climate-driven change and melting forecast for the 21st Century, our findings document the potential for biogeochemical cycling and multi-trophic interactions along the peninsula to be increasingly regulated by glacial discharge, altering food-web interactions

    Control of sulphide during anaerobic treatment of S-containing wastewaters by adding limited amounts of oxygen or nitrate

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    Sulphide generated during anaerobic treatment of S-containing wastewaters represents an environmental problem. Adding limited amounts of oxygen or nitrate (or nitrite) to biologically (or chemically) oxidise sulphide forms a simple process level strategy to control this problem. This short review evaluates the feasibility and limitations of this strategy on the basis of the results of bioreactor studies.Sulphide generated during anaerobic treatment of S-containing wastewaters represents an environmental problem. Adding limited amounts of oxygen or nitrate (or nitrite) to biologically (or chemically) oxidise sulphide forms a simple process level strategy to control this problem. This short review evaluates the feasibility and limitations of this strategy on the basis of the results of bioreactor studies.Spanish Ministry of Education and Science; AEA Technology Environment; Nova Energie; The Swedish Gas Centre; University of Southern Denmark

    The Ontario Mother and Infant Study (TOMIS) III: A multi-site cohort study of the impact of delivery method on health, service use, and costs of care in the first postpartum year

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    Abstract Background The caesarean section rate continues to rise globally. A caesarean section is inarguably the preferred method of delivery when there is good evidence that a vaginal delivery may unduly risk the health of a woman or her infant. Any decisions about delivery method in the absence of clear medical indication should be based on knowledge of outcomes associated with different childbirth methods. However, there is lack of sold evidence of the short-term and long-term risks and benefits of a planned caesarean delivery compared to a planned vaginal delivery. It also is important to consider the economic aspects of caesarean sections, but very little attention has been given to health care system costs that take into account services used by women for themselves and their infants following hospital discharge. Methods and design The Ontario Mother and Infant Study III is a prospective cohort study to examine relationships between method of delivery and maternal and infant health, service utilization, and cost of care at three time points during the year following postpartum hospital discharge. Over 2500 women were recruited from 11 hospitals across the province of Ontario, Canada, with data collection occurring between April 2006 and October 2008. Participants completed a self-report questionnaire in hospital and structured telephone interviews at 6 weeks, 6 months, and 12 months after discharge. Data will be analyzed using generalized estimating equation, a special generalized linear models technique. A qualitative descriptive component supplements the survey approach, with the goal of assisting in interpretation of data and providing explanations for trends in the findings. Discussion The findings can be incorporated into patient counselling and discussions about the advantages and disadvantages of different delivery methods, potentially leading to changes in preferences and practices. In addition, the findings will be useful to hospital- and community-based postpartum care providers, managers, and administrators in guiding risk assessment and early intervention strategies. Finally, the research findings can provide the basis for policy modification and implementation strategies to improve outcomes and reduce costs of care
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