Zipf's law and the diversity of biology newsgroups

Usenet newsgroups provide a popular means of scientific communication. We demonstrate striking order in the diversity of biology newsgroups: Submissions to newsgroups obey a form of Zipf's law, a simple power law for the frequency of posts as a function of the rank, by posting, of contributors. We show that a simple stochastic process, due to Günther et al. (1992, 1996), Levitin and Schapiro (1993), and Schapiro (1994), accounts for this pattern and reproduces many of the properties of newsgroups. This model successfully predicts the relative contribution from each poster in terms of the size, the number of posters and total posts, of the newsgroup.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43673/1/11192_2004_Article_5116106.pd

Translating Marine Animal Tracking Data into Conservation Policy and Management

There have been efforts around the globe to track individuals of many marine species and assess their movements and distribution with the putative goal of supporting their conservation and management. Determining whether, and how, tracking data have been successfully applied to address real-world conservation issues is however difficult. Here, we compile a broad range of case studies from diverse marine taxa to show how tracking data have helped inform conservation policy and management, including reductions in fisheries bycatch and vessel strikes, and the design and administration of marine protected areas and important habitats. Using these examples, we highlight pathways through which the past and future investment in collecting animal tracking data might be better used to achieve tangible conservation benefits

A Density-Dependent Switch Drives Stochastic Clustering and Polarization of Signaling Molecules

Positive feedback plays a key role in the ability of signaling molecules to form highly localized clusters in the membrane or cytosol of cells. Such clustering can occur in the absence of localizing mechanisms such as pre-existing spatial cues, diffusional barriers, or molecular cross-linking. What prevents positive feedback from amplifying inevitable biological noise when an un-clustered “off” state is desired? And, what limits the spread of clusters when an “on” state is desired? Here, we show that a minimal positive feedback circuit provides the general principle for both suppressing and amplifying noise: below a critical density of signaling molecules, clustering switches off; above this threshold, highly localized clusters are recurrently generated. Clustering occurs only in the stochastic regime, suggesting that finite sizes of molecular populations cannot be ignored in signal transduction networks. The emergence of a dominant cluster for finite numbers of molecules is partly a phenomenon of random sampling, analogous to the fixation or loss of neutral mutations in finite populations. We refer to our model as the “neutral drift polarity model.” Regulating the density of signaling molecules provides a simple mechanism for a positive feedback circuit to robustly switch between clustered and un-clustered states. The intrinsic ability of positive feedback both to create and suppress clustering is a general mechanism that could operate within diverse biological networks to create dynamic spatial organization

Genome-Wide Meta-Analysis Identifies Regions on 7p21 (AHR) and 15q24 (CYP1A2) As Determinants of Habitual Caffeine Consumption

We report the first genome-wide association study of habitual caffeine intake. We included 47,341 individuals of European descent based on five population-based studies within the United States. In a meta-analysis adjusted for age, sex, smoking, and eigenvectors of population variation, two loci achieved genome-wide significance: 7p21 (P = 2.4×10−19), near AHR, and 15q24 (P = 5.2×10−14), between CYP1A1 and CYP1A2. Both the AHR and CYP1A2 genes are biologically plausible candidates as CYP1A2 metabolizes caffeine and AHR regulates CYP1A2

Association between solar insolation and a history of suicide attempts in bipolar I disorder

In many international studies, rates of completed suicide and suicide attempts have a seasonal pattern that peaks in spring or summer. This exploratory study investigated the association between solar insolation and a history of suicide attempt in patients with bipolar I disorder. Solar insolation is the amount of electromagnetic energy from the Sun striking a surface area on Earth. Data were collected previously from 5536 patients with bipolar I disorder at 50 collection sites in 32 countries at a wide range of latitudes in both hemispheres. Suicide related data were available for 3365 patients from 310 onset locations in 51 countries. 1047 (31.1%) had a history of suicide attempt. There was a significant inverse association between a history of suicide attempt and the ratio of mean winter solar insolation/mean summer solar insolation. This ratio is smallest near the poles where the winter insolation is very small compared to the summer insolation. This ratio is largest near the equator where there is relatively little variation in the insolation over the year. Other variables in the model that were positively associated with suicide attempt were being female, a history of alcohol or substance abuse, and being in a younger birth cohort. Living in a country with a state-sponsored religion decreased the association. (All estimated coefficients p <0.01). In summary, living in locations with large changes in solar insolation between winter and summer may be associated with increased suicide attempts in patients with bipolar disorder. Further investigation of the impacts of solar insolation on the course of bipolar disorder is needed.Peer reviewe

IMPRoving Outcomes for children exposed to domestic ViolencE (IMPROVE): an evidence synthesis

BackgroundExposure to domestic violence and abuse (DVA) during childhood and adolescence increases the risk of negative outcomes across the lifespan.ObjectivesTo synthesise evidence on the clinical effectiveness, cost-effectiveness and acceptability of interventions for children exposed to DVA, with the aim of making recommendations for further research.Design(1) A systematic review of controlled trials of interventions; (2) a systematic review of qualitative studies of participant and professional experience of interventions; (3) a network meta-analysis (NMA) of controlled trials and cost-effectiveness analysis; (4) an overview of current UK provision of interventions; and (5) consultations with young people, parents, service providers and commissioners.SettingsNorth America (11), the Netherlands (1) and Israel (1) for the systematic review of controlled trials of interventions; the USA (4) and the UK (1) for the systematic review of qualitative studies of participant and professional experience of interventions; and the UK for the overview of current UK provision of interventions and consultations with young people, parents, service providers and commissioners.ParticipantsA total of 1345 children for the systematic review of controlled trials of interventions; 100 children, 202 parents and 39 professionals for the systematic review of qualitative studies of participant and professional experience of interventions; and 16 young people, six parents and 20 service providers and commissioners for the consultation with young people, parents, service providers and commissioners.InterventionsPsychotherapeutic, advocacy, parenting skills and advocacy, psychoeducation, psychoeducation and advocacy, guided self-help.Main outcome measuresInternalising symptoms and externalising behaviour, mood, depression symptoms and diagnosis, post-traumatic stress disorder symptoms and self-esteem for the systematic review of controlled trials of interventions and NMA; views about and experience of interventions for the systematic review of qualitative studies of participant and professional experience of interventions and consultations.Data sourcesMEDLINE, Cumulative Index to Nursing and Allied Health Literature, PsycINFO, EMBASE, Cochrane Central Register of Controlled Trials, Science Citation Index, Applied Social Sciences Index and Abstracts, International Bibliography of the Social Sciences, Social Services Abstracts, Social Care Online, Sociological Abstracts, Social Science Citation Index, World Health Organization trials portal and clinicaltrials.gov.Review methodsA narrative review; a NMA and incremental cost-effectiveness analysis; and a qualitative synthesis.ResultsThe evidence base on targeted interventions was small, with limited settings and types of interventions; children were mostly &lt; 14 years of age, and there was an absence of comparative studies. The interventions evaluated in trials were mostly psychotherapeutic and psychoeducational interventions delivered to the non-abusive parent and child, usually based on the child’s exposure to DVA (not specific clinical or broader social needs). Qualitative studies largely focused on psychoeducational interventions, some of which included the abusive parent. The evidence for clinical effectiveness was as follows: 11 trials reported improvements in behavioural or mental health outcomes, with modest effect sizes but significant heterogeneity and high or unclear risk of bias. Psychoeducational group-based interventions delivered to the child were found to be more effective for improving mental health outcomes than other types of intervention. Interventions delivered to (non-abusive) parents and to children were most likely to be effective for improving behavioural outcomes. However, there is a large degree of uncertainty around comparisons, particularly with regard to mental health outcomes. In terms of evidence of cost-effectiveness, there were no economic studies of interventions. Cost-effectiveness was modelled on the basis of the NMA, estimating differences between types of interventions. The outcomes measured in trials were largely confined to children’s mental health and behavioural symptoms and disorders, although stakeholders’ concepts of success were broader, suggesting that a broader range of outcomes should be measured in trials. Group-based psychoeducational interventions delivered to children and non-abusive parents in parallel were largely acceptable to all stakeholders. There is limited evidence for the acceptability of other types of intervention. In terms of the UK evidence base and service delivery landscape, there were no UK-based trials, few qualitative studies and little widespread service evaluation. Most programmes are group-based psychoeducational interventions. However, the funding crisis in the DVA sector is significantly undermining programme delivery.ConclusionsThe evidence base regarding the acceptability, clinical effectiveness and cost-effectiveness of interventions to improve outcomes for children exposed to DVA is underdeveloped. There is an urgent need for more high-quality studies, particularly trials, that are designed to produce actionable, generalisable findings that can be implemented in real-world settings and that can inform decisions about which interventions to commission and scale. We suggest that there is a need to pause the development of new interventions and to focus on the systematic evaluation of existing programmes. With regard to the UK, we have identified three types of programme that could be justifiably prioritised for further study: psycho-education delivered to mothers and children, or children alone; parent skills training in combination with advocacy: and interventions involving the abusive parent/caregiver. We also suggest that there is need for key stakeholders to come together to explicitly identify and address the structural, practical and cultural barriers that may have hampered the development of the UK evidence base to date.Future work recommendationsThere is a need for well-designed, well-conducted and well-reported UK-based randomised controlled trials with cost-effectiveness analyses and nested qualitative studies. Development of consensus in the field about core outcome data sets is required. There is a need for further exploration of the acceptability and effectiveness of interventions for specific groups of children and young people (i.e. based on ethnicity, age, trauma exposure and clinical profile). There is also a need for an investigation of the context in which interventions are delivered, including organisational setting and the broader community context, and the evaluation of qualities, qualifications and disciplines of personnel delivering interventions. We recommend prioritisation of psychoeducational interventions and parent skills training delivered in combination with advocacy in the next phase of trials, and exploratory trials of interventions that engage both the abusive and the non-abusive parent.Study registrationThis study is registered as PROSPERO CRD42013004348 and PROSPERO CRD420130043489.FundingThe National Institute for Health Research Public Health Research programme.</jats:sec

Variations in seasonal solar insolation are associated with a history of suicide attempts in bipolar I disorder

Background: Bipolar disorder is associated with circadian disruption and a high risk of suicidal behavior. In a previous exploratory study of patients with bipolar I disorder, we found that a history of suicide attempts was associated with differences between winter and summer levels of solar insolation. The purpose of this study was to confirm this finding using international data from 42% more collection sites and 25% more countries. Methods: Data analyzed were from 71 prior and new collection sites in 40 countries at a wide range of latitudes. The analysis included 4876 patients with bipolar I disorder, 45% more data than previously analyzed. Of the patients, 1496 (30.7%) had a history of suicide attempt. Solar insolation data, the amount of the sun’s electromagnetic energy striking the surface of the earth, was obtained for each onset location (479 locations in 64 countries). Results: This analysis confirmed the results of the exploratory study with the same best model and slightly better statistical significance. There was a significant inverse association between a history of suicide attempts and the ratio of mean winter insolation to mean summer insolation (mean winter insolation/mean summer insolation). This ratio is largest near the equator which has little change in solar insolation over the year, and smallest near the poles where the winter insolation is very small compared to the summer insolation. Other variables in the model associated with an increased risk of suicide attempts were a history of alcohol or substance abuse, female gender, and younger birth cohort. The winter/summer insolation ratio was also replaced with the ratio of minimum mean monthly insolation to the maximum mean monthly insolation to accommodate insolation patterns in the tropics, and nearly identical results were found. All estimated coefficients were significant at p &lt; 0.01. Conclusion: A large change in solar insolation, both between winter and summer and between the minimum and maximum monthly values, may increase the risk of suicide attempts in bipolar I disorder. With frequent circadian rhythm dysfunction and suicidal behavior in bipolar disorder, greater understanding of the optimal roles of daylight and electric lighting in circadian entrainment is needed