Find research datasets worth reusing

Data from: What is behind the variation in mate quality dependent sex ratio adjustment? – A meta-analysis

Theory predicts that parents adjust the sex ratio of their brood to the sexually selected traits of their mate because the reproductive success of sons may be more dependent on inherited paternal attractiveness than that of daughters. Empirical studies vary in terms of whether they support the theory, and this variation has often been regarded as evidence against sex ratio adjustment or has been ascribed to methodological differences. Applying phylogenetic meta-analyses, we aimed to find biological explanations for the variation observed in songbirds. In particular, we tested the role extra-pair paternity, because infidelity occurs in the majority of these species and may reduce the adaptive value of adjusting brood sex ratio to the phenotype of the social mate. However, we found that the variation in effect sizes was unrelated to the proportion of extra-pair paternity. Thus future studies should consider that mate quality dependent sex ratio adjustment may be driven by direct (material) rather than indirect (genetic) benefits. We also tested if the effect sizes are influenced by whether the focal male trait is indeed under sexual selection as it is assumed by the sex allocation theory. We found that for male traits with proven role in sexual selection, effect sizes significantly differed from the null expectation of random production of sons and daughters. For male traits with only presumed sexual role in sexual selection, the deviation from the null expectation was less convincing, and the effect sizes were significantly smaller. This result indicates that studies that neglect the assumptions of the hypotheses concerned, may lead to the underestimation of the mean effect size and, eventually, false conclusions.

Data from: Evidence assessing the diagnostic performance of medical smartphone apps: a systematic review and exploratory meta-analysis

Objective: The number of mobile applications addressing health topics is increasing. Whether these apps underwent scientific evaluation is unclear. We comprehensively assessed papers investigating the diagnostic value of available diagnostic health applications using in-built smartphone-sensors. Methods: Systematic Review - Medline, Scopus, Web of Science inclusive Medical Informatics and Business Source Premier (by citation of reference) were searched from inception until December 15th, 2016. Checking of reference lists of review articles and of included articles complemented electronic searches. We included all studies investigating a health application that used in-built sensors of a smartphone for diagnosis of disease. The methodological quality of 11 studies used in an exploratory meta-analysis was assessed with the QUADAS-2 tool and the reporting quality with the STARD statement. Sensitivity and specificity of studies reporting two-by-two tables were calculated and summarized. Results We screened 3'296 references for eligibility. Eleven studies, most of them assessing melanoma screening apps, reported 17 two-by-two tables. Quality assessment revealed high risk of bias in all studies. Included papers studied 1'048 subjects (758 with the target conditions and 290 healthy volunteers). Overall, the summary estimate for sensitivity was 0.82 (95 % confidence interval (CI); 0.56 to 0.94) and 0.89 (95 %CI; 0.70 to 0.97) for specificity. Conclusions The diagnostic evidence of available health apps on Apple's and Google's app stores is scarce. Consumers and healthcare professionals should be aware of this when using or recommending them.

Data from: Meta-analysis reveals enhanced growth of marine harmful algae from temperate regions with warming and elevated CO2 levels

Elevated pCO2 and warming may promote algal growth and toxin production, and thereby possibly support the proliferation and toxicity of HABs. Here, we tested whether empirical data supports this hypothesis using a meta-analytic approach and investigated the responses of growth rate and toxin content or toxicity of numerous marine and estuarine HAB species to elevated pCO2 and warming. Most of the available data on HAB responses towards the two tested climate change variables concerns dinoflagellates, as many members of this phytoplankton group are known to cause HAB outbreaks. Toxin content and toxicity did not reveal a consistent response towards both tested climate change variables, while growth rate increased consistently with elevated pCO2 . Warming also led to higher growth rates, but only for species isolated at higher latitudes. The observed gradient in temperature growth responses shows the potential for enhanced development of HABs at higher latitudes. Increases in growth rates with more CO2 may present an additional competitive advantage for HAB species, particularly as CO2 was not shown to enhance growth rate of other non-HAB phytoplankton species. However, this may also be related to the difference in representation of dinoflagellate and diatom species in the respective HAB and non-HAB phytoplankton groups. Since the proliferation of HAB species may strongly depend on their growth rates, our results warn for a greater potential of dinoflagellate HAB development in future coastal waters, particularly in temperate regions.

opencc-zeroDec 2015View details →

Data from: Efficacy and safety of bevacizumab plus erlotinib versus bevacizumab or erlotinib alone in the treatment of non-small-cell lung cancer: a systematic review and meta-analysis

Objectives: Bevacizumab and erlotinib inhibit different tumour growth pathways, and both exhibit beneficial effects in the treatment of non-small-cell lung cancer (NSCLC). However, the efficacy of bevacizumab in combination with erlotinib remains controversial. Therefore, we conducted a meta-analysis to compare combination treatment with bevacizumab and erlotinib to bevacizumab or erlotinib monotherapy in the treatment of NSCLC. Methods: Randomised controlled trials (RCTs) published in PubMed, Web of Science and EMBASE were systematically reviewed. The main outcome measures included overall survival (OS), progression-free survival (PFS), overall response rate (ORR) and adverse events. Results were expressed as HRs or risk ratios (RRs) with 95% CIs. Results: 5 RCTs involving a total of 1736 patients were included in this meta-analysis. The combination of bevacizumab and erlotinib significantly improved PFS (HR=0.63, 95% CI 0.53 to 0.75; p=0.000) and the ORR (RR=1.91, 95% CI 1.19 to 3.06; p=0.007) in the second-line treatment of NSCLC compared with bevacizumab or erlotinib alone. However, no significant difference in OS was observed between the combination and monotherapy groups (HR=0.96, 95% CI 0.83 to 1.11; p=0.573). A subgroup analysis has shown that the greatest PFS benefit was associated with an age of <65 years(HR=0.74, 95% CI 0.57 to 0.96; p=0.026), Asian/Pacific Islander ethnicity (HR=0.23, 95% CI 0.10 to 0.54; p=0.001), Eastern Cooperative Oncology Group performance status (ECOG PS) 1 (HR=0.82, 95% CI 0.68 to 0.98; p=0.033), stage IIIB or IV disease (HR=0.68, 95% CI 0.57 to 0.82; p=0.000) and no history of smoking (HR=0.48, 95% CI 0.32 to 0.71; p=0.000). The incidence of grade 3/4 adverse events such as rash and diarrhoea was higher in the combination group than in the monotherapy group. Conclusions: The addition of bevacizumab to erlotinib can significantly improve PFS and the ORR in the second-line treatment of NSCLC with an acceptable and manageable risk of rash and diarrhoea. Further well-conducted, large-scale trials are needed to validate these findings.

Data from: Copepod respiration increases by 7% per degree °C increase in temperature: a meta-analysis

Exponential increase in respiration rate with increasing temperature in poikilotherms is well documented, however, the overall rate of change varies greatly across copepod taxa. Studies often report magnitude of change, but the rate of change in respiration across multiple temperatures is equivocal. We used 32 studies spanning 78 years of research and 50 copepod species (three orders) to quantify percent increase in respiration rates per one-unit increase in temperature. We found that copepod respiration rates increased with temperature by 7% across three well-studied orders, Calanoida, Cyclopoida, and Harpacticoida. Neither food availability nor scaling respiration to copepod dry weight affected the rate of change of respiration rates. Studies using Winkler titration to measure oxygen consumption produced significantly larger percent changes in respiration, whereas newer methods such as fiber optics produced smaller effects. These results have far reaching implications, suggesting that copepods can adapt to increasing temperatures brought forth by climate change.

Data from: On the relationship between body condition and parasite infection in wildlife: a review and meta‐analysis

Body condition metrics are widely used to infer animal health and to assess costs of parasite infection. Since parasites harm their hosts, ecologists might expect negative relationships between infection and condition in wildlife, but this assumption is challenged by studies showing positive or null condition–infection relationships. Here, we outline common condition metrics used by ecologists in studies of parasitism, and consider mechanisms that cause negative, positive, and null condition–infection relationships in wildlife systems. We then perform a meta‐analysis of 553 condition–infection relationships from 187 peer‐reviewed studies of animal hosts, analysing observational and experimental records separately, and noting whether authors measured binary infection status or intensity. Our analysis finds substantial heterogeneity in the strength and direction of condition–infection relationships, a small, negative average effect size that is stronger in experimental studies, and evidence for publication bias towards negative relationships. The strongest predictors of variation in study outcomes are host thermoregulation and the methods used to evaluate body condition. We recommend that studies aiming to assess parasite impacts on body condition should consider host–parasite biology, choose condition measures that can change during the course of infection, and employ longitudinal surveys or manipulate infection status when feasible.

Data from: Mandated reporters' experiences with reporting child maltreatment: a meta-synthesis of qualitative studies

Objective: To systematically search for research about the effectiveness of mandatory reporting of child maltreatment and to synthesize qualitative research that explores mandated reporters' (MRs) experiences with reporting. Design: As no studies assessing the effectiveness of mandatory reporting were retrieved from our systematic search, we conducted a meta-synthesis of retrieved qualitative research. Searches in Medline (OVID), Embase, PsycINFO, CINAHL, Sociological Abstracts, ERIC, Criminal Justice Abstracts, and Cochrane Library yielded over 6000 citations, which were deduplicated and then screened by two independent reviewers. English-language, primary qualitative studies that investigated MRs' experiences with reporting of child maltreatment were included. Critical appraisal involved a modified checklist from the Critical Appraisal Skills Programme (CASP) and qualitative meta-synthesis was used to combine results from the primary studies. Setting: All healthcare and social-service settings implicated by mandatory reporting laws were included. Included studies crossed nine high-income countries (United States, Australia, Sweden, Taiwan, Canada, Norway, Finland, Israel and Cyprus) and three middle-income countries (South Africa, Brazil, and El Salvador). Participants: The studies represent the views of 1088 MRs. Outcomes: Factors that influence MRs' decision to report and MRs' views towards and experiences with mandatory reporting of child maltreatment. Results: Forty-four articles reporting 42 studies were included. Findings indicate that MRs struggle to identify and respond to less overt forms of child maltreatment. While some articles (14%) described positive experiences MRs had with the reporting process, negative experiences were reported in 73% of articles and included accounts of harm to therapeutic relationships and child death following removal from their family of origin. Conclusions: The findings of this meta-synthesis suggest that there are many potentially harmful experiences associated with mandatory reporting and that research on the effectiveness of this process is urgently needed.

Data from: Virulence-driven trade-offs in disease transmission: a meta-analysis

The virulence--transmission trade-off hypothesis proposed more than 30 years ago is the cornerstone in the study of host-parasite co-evolution. This hypothesis rests on the premise that virulence is an unavoidable and increasing cost because the parasite uses host resources to replicate. This cost associated with replication ultimately results in a deceleration in transmission rate because increasing within-host replication increases host mortality. Empirical tests of predictions of the hypothesis have found mixed support, which cast doubt about its overall generalizability. To quantitatively address this issue, we conducted a meta-analysis of 30 empirical studies, after reviewing over 4000 published papers, focusing on the four core relationships between (1) virulence and recovery rate, (2) within-host replication rate and virulence, (3) within-host replication and transmission rate, and (4) virulence and transmission rate. We found strong support for an increasing relationship between replication and virulence, and replication and transmission. While the overall mean effect suggests that these relationships decelerate with increasing parasite replication, which theoretically arises from limited host resources to exploit, the effect was uncertain due to high within-study variability. There was insufficient data to quantitatively test the other two core relationships predicted by the theory. Overall, the results suggest that the current empirical evidence provides partial support for the trade-off hypothesis, but more work remains to be done.

Data from: Correction for bias in meta-analysis of little-replicated studies

1. Meta-analyses conventionally weight study estimates on the inverse of their error variance, in order to maximize precision. Unbiased variability in the estimates of these study-level error variances increases with the inverse of study-level replication. Here we demonstrate how this variability accumulates asymmetrically across studies in precision-weighted meta-analysis, to cause undervaluation of the meta-level effect size or its error variance (the meta-effect and meta-variance). 2. Small samples, typical of the ecological literature, induce big sampling errors in variance estimation, which substantially bias precision-weighted meta-analysis. Simulations revealed that biases differed little between random- and fixed-effects tests. Meta-estimation of a one-sample mean from 20 studies, with sample sizes of 3 to 20 observations, undervalued the meta-variance by ~20%. Meta-analysis of two-sample designs from 20 studies, with sample sizes of 3 to 10 observations, undervalued the meta-variance by 15-20% for the log response ratio (lnR); it undervalued the meta-effect by ~10% for the standardised mean difference (SMD). 3. For all estimators, biases were eliminated or reduced by a simple adjustment to the weighting on study precision. The study-specific component of error variance prone to sampling error and not parametrically attributable to study-specific replication was replaced by its cross-study mean, on the assumption of random sampling from the same population variance for all studies, and sufficient studies for averaging. Weighting each study by the inverse of this mean-adjusted error variance universally improved accuracy in estimation of both the meta-effect and its significance, regardless of number of studies. For comparison, weighting only on sample size gave the same improvement in accuracy, but could not sensibly estimate significance. 4. For the one-sample mean and two-sample lnR, adjusted weighting also improved estimation of between-study variance by DerSimonian-Laird and REML methods. For random-effects meta-analysis of SMD from little-replicated studies, the most accurate meta-estimates obtained from adjusted weights following conventionally-weighted estimation of between-study variance. 5. We recommend adoption of weighting by inverse adjusted-variance for meta-analyses of well- and little-replicated studies, because it improves accuracy and significance of meta-estimates, and it can extend the scope of the meta-analysis to include some studies without variance estimates.

opencc-zeroDec 2015View details →

Data from: Species diversity can be overestimated by a fixed empirical threshold: insights from DNA barcoding of the genus Cletus (Hemiptera: Coreidae) and the meta-analysis of COI data from previous phylogeographical studies

The use of genetic distances to identify species within the framework of DNA barcoding has to some extent improved the development of biodiversity studies. However, using a fixed empirical threshold to delimit species may lead to overestimating species diversity. In this study, we use a new data set of COI sequences for 366 specimens within the genus of Cletus as well as conduct an analysis on the same genetic data for collected morphologically defined species from previous phylogeographical studies, to test whether high intraspecific genetic divergences are common with the premises of comprehensive sampling. The results indicate C. graminis Hsiao & Cheng 1964, is the same species with C. punctiger (Dallas, 1852) and should be synonymized and that the distributional record of C. pugnator (Fabricius, 1787) in China is correct. High intraspecific genetic differentiations (0%–4.35%) were found in C. punctiger. Furthermore, as to the mined data, the maximum intraspecific K2P distances of 186 species (48.44% of 384) exceed 3%, and 101 species (26.30%) can be divided into two or more clusters with a threshold of 3% in cluster analysis. If genetic distance is used to delimit species boundaries, the minimum interspecific K2P distance of the congeneric species should be considered rather than only using the fixed empirical value; otherwise, the species richness may be overestimated in some cases.

Data from: Impacts of honeybee density on crop yield: a meta-analysis

1. There is increasing recognition that pollination deficits are limiting crop yields worldwide. However, management strategies for optimal insect pollination are still unclear for most crops. Current management focuses on providing high densities of honeybees, but recommended densities are highly variable, even within single crops and cultivars. 2. We performed an extensive literature search to record honeybee densities (colony density and/or flower visitation rates) and crop productivity (fruit set, seed set, fruit weight, and/or yield). Effect sizes were represented as the difference in crop productivity between the two most extreme levels of honeybee densities. 3. Out of 795 reviewed studies, only 22 analysed the effect of at least two levels of honeybee densities on crop productivity (reporting 60 resulting effect sizes in total). Moreover, few recommendations for crop pollination management are based on results from controlled experimental designs, and with comparable methodology. 4. We found that both colony density and visitation rates increased all the productivity variables. However, effects were non-linear for visitation rates, suggesting that there is an optimum (mean of 8-10 visits per flower) beyond which more honeybees are not beneficial (or even detrimental) for crop productivity. 5. Effect sizes for visitation rates were greater than that for colony densities, suggesting that visitation rates are a more direct measure of the pollination process. Data on the relation between colony density and visitation rates are lacking. Interestingly, effect sizes for visitation rates were greater for crops with separate sexes than those with hermaphroditic flowers; therefore, the benefits of honeybee pollination vary according to the crop biology. 6. Synthesis and applications. Current practices for crop pollination assume that more honeybees are always better for crop yield, even if the effect of this management on crop production still unclear. In contrast, our analyses suggest that there is an optimum for honeybee densities. Despite the importance of honeybees and pollinator-dependent crops worldwide, there is a lack of studies designed for finding such an optimal level of crop pollination. Our analyses further suggest that visitation rates could be used as a proxy to guide management recommendations such as colony density and spatial arrangement.

Data from: Diabetes mellitus and the risk of fractures at specific sites: a meta-analysis

Objective: Diabetes mellitus (DM) is associated with an increased fracture risk; however, the impact of DM and subsequent fracture at different sites and the associations according to patient characteristics remain unknown. Design: Meta-analysis. Data Sources: The PubMed, EMBASE, and Cochrane Library databases were searched from inception to March 2018. Eligibility Criteria: We included prospective and retrospective cohort studies on the associations of DM and subsequent fracture risk at different sites. Data extraction and synthesis: Two authors independently extracted data and assessed the study quality. Relative risks (RRs) with 95% confidence intervals (CIs) were calculated using a random-effects model, and the heterogeneity across the included studies was evaluated using I2 and Q statistics. Results: Overall, DM was associated with an increased risk of total (RR: 1.32; 95% CI: 1.17–1.48; P<0.001), hip (RR: 1.77; 95% CI: 1.56–2.02; P<0.001), upper arm (RR: 1.47; 95% CI: 1.02–2.10; P=0.037), and ankle fractures (RR: 1.24; 95% CI: 1.10–1.40; P<0.001), whereas DM had no significant impact on the incidence of distal forearm (RR: 1.02; 95% CI: 0.88–1.19; P=0.809) and vertebral fractures (RR: 1.56; 95% CI: 0.78–3.12; P=0.209). RR ratios suggested that compared with type 2 DM (T2DM) patients, type 1 DM (T1DM) patients had greater risk of total (RR ratio: 1.24; 95% CI: 1.08–1.41; P=0.002), hip (RR ratio: 3.43; 95% CI: 2.27–5.17; P<0.001), and ankle fractures (RR ratio: 1.71; 95% CI: 1.06 –2.78; P=0.029). Although no other significant differences were observed between subgroups, the association of DM with upper arm or ankle, vertebrae, and total fracture differed according to sex, study design, and country, respectively. Conclusions: DM patients had greater risks of total, hip, upper arm, and ankle fractures, with T1DM having a more harmful effect than T2DM.

opencc-zeroDec 2011View details →

Data from: Do animals living in larger groups experience greater parasitism? A meta-analysis

Parasitism is widely viewed as the primary cost of sociality and a constraint on group size, yet studies report varied associations between group size and parasitism. Using the largest database of its kind, we performed a meta-analysis of 69 studies of the relationship between group size and parasite risk, as measured by parasitism and immune defenses. We predicted a positive correlation between group size and parasitism with organisms that show contagious and environmental transmission, and a negative correlation for searching parasites, parasitoids, and possibly vector-borne parasites (based on the encounter-dilution effect). Overall, we found a positive effect of group size (r=0.187) that varied in magnitude across transmission modes and measures of parasite risk, with only weak indications of publication bias. Among different groups of hosts, we found a stronger relationship between group size and parasite risk in birds than in mammals, which may be driven by ecological and social factors. A meta-regression showed that effect sizes increased with maximum group size. Phylogenetic meta-analyses revealed no evidence for phylogenetic signal in the strength of the group size-parasitism relationship. We conclude that group size is a weak predictor of parasite risk except in species that live in large aggregations, such as colonial birds, where effect sizes are larger.

opencc-zeroDec 2013View details →

Data from: The genetic basis of the fitness costs of antimicrobial resistance: a meta-analysis approach

The evolution of antibiotic resistance carries a fitness cost, expressed in terms of reduced competitive ability in the absence of antibiotics. This cost plays a key role in the dynamics of resistance by generating selection against resistance when bacteria encounter an antibiotic-free environment. Previous work has shown that the cost of resistance is highly variable, but the underlying causes remain poorly understood. Here, we use a meta-analysis of the published resistance literature to determine how the genetic basis of resistance influences its cost. We find that on average chromosomal resistance mutations carry a larger cost than acquiring resistance via a plasmid. This may explain why resistance often evolves by plasmid acquisition. Second, we find that the cost of plasmid acquisition increases with the breadth of its resistance range. This suggests a potentially important limit on the evolution of extensive multidrug resistance via plasmids. We also find that epistasis can significantly alter the cost of mutational resistance. Overall, our study shows that the cost of antimicrobial resistance can be partially explained by its genetic basis. It also highlights both the danger associated with plasmidborne resistance and the need to understand why resistance plasmids carry a relatively low cost.

Data from: Earthworms affect plant growth and resistance against herbivores: a meta-analysis

1. Subterranean detritivores such as earthworms can increase soil nutrient availability through their burrowing and casting activities. A number of recent studies have explored whether these changes caused by earthworms may in turn affect plant performance and resistance to herbivores, but no formal synthesis of this literature has been conducted to date. 2. We here formally tested for the effects of earthworms on plant growth, resistance and chemical defence against insect herbivores by performing a meta-analysis of the existing literature up to 2016. We also explored ecological factors that might explain among-studies variation in the magnitude of the earthworm effects on plant growth and resistance. 3. We found that earthworm presence increases plant growth (by 20 %) and nitrogen content (by 11 %). Overall, earthworms did not affect plant resistance against chewing herbivores (caterpillars, slugs and rootworms), and even led to a 22 % decrease in plant resistance against phloem-feeding herbivores (aphids). However, earthworm presence increased production of chemical defences by 31% when plants where attacked by cell-feeders (thrips), and resulted in an 81 % increase in resistance against thrips. The magnitude of earthworm effects was stronger when earthworm inoculations consisted of a mix of species and ecological types, and when densities of earthworms were high. 4. These results suggest that earthworm presence is an important factor underlying natural variation in plant defences against herbivores, and call for a better integration of the soil fauna in the studies of plant-herbivore interaction, both for applied and fundamental research.

Data from: Living in a high CO2 world: a global meta-analysis shows multiple trait-mediated responses of fish to ocean acidification

Understanding how marine organisms will be affected by global change is of primary importance to ensure ecosystem functioning and nature contributions to people. This study meets the call for addressing how life-history traits mediate effects of ocean acidification on fish. We built a database of overall and trait-mediated responses of teleost fish to future CO2 levels by searching the scientific literature. Using a meta-analytical approach, we investigated the effects of projected CO2 levels by IPCC for 2050-2070 and 2100 on fish eco-physiology and behavior from 320 contrasts on 42 species, stemming from polar to tropical regions. Moreover, since organisms may experience a mosaic of carbonate chemistry in coastal environments (e.g. in estuaries, upwelling zones and intertidal habitats), which may have higher pCO2 values than open ocean waters, we assessed responses from additional 103 contrasts on 21 fish species using pCO2 levels well above IPCC projections. Under mid- and end-of-century CO2 emission scenarios, we found multiple CO2-dose dependent effects on calcification, resting metabolic rate, yolk, behavioral performances, along with increased predation risk and decreased foraging, particularly for larvae. Importantly, many of the traits considered will not confer fish tolerance to elevated CO2 and far-reaching ecological consequences on fish population replenishment and community structure will likely occur. Extreme CO2 levels well above IPCC projections showed effects on fish mortality and calcification, while growth, metabolism and yolk were unaffected. CO2 exposures in short-term experiments increased fish mortality, which in turn decreased in longer-term exposures. Whatever the elevated CO2 levels considered, some key biological processes (e.g. reproduction, development, habitat choice) resulted critically understudied. Fish are an important resource for livelihoods in coastal communities and a key component for stability of marine ecosystems. Given the multiple trait-mediated effects evidenced here, we stress the need to fill the knowledge gap on important eco-physiological processes and to expand the number and duration of ocean acidification studies to multi-generational, multiple stressor (e.g. warming, hypoxia, fishing) and species interactions experiments to better elucidate complex ecosystem-level changes and how these changes might alter provisioning of ecosystem services.

opencc-zeroDec 2015View details →

Data from: The negative effects of pathogen-infected prey on predators: a meta-analysis

Intra-guild predation (IGP) – where a top predator (IGPred) consumes both a basal resource and a competitor for that resource (IGPrey) – has become a fundamental part of understanding species interactions and community dynamics. IGP communities composed of intraguild predators and prey have been well studied; however, we know less about IGP communities composed of predators, pathogens, and resources. Resource quality plays an important role in community dynamics and may influence IGP dynamics as well. We conducted a meta-analysis on predator–pathogen–resource communities to determine whether resource quality mediated by the pathogen affected predator life-history traits and if these effects met the theoretical constraints of IGP communities. To do this, we summarized results from studies that investigated the use of predators and pathogens to control insect pests. In these systems, the predators are the IGPred and pathogens are the IGPrey. We found that consumer longevity, fecundity, and survival decreased by 26%, 31% and 13% respectively, when predators consumed pathogen-infected prey, making the infected prey a low quality resource. Predators also significantly preferred healthy prey over infected prey. When we divided consumers by enemy type, strict predators (e.g. wolf spiders) had no preference while parasitoids preferred healthy prey. Our results suggest that communities containing parasitoids and pathogens may rarely exhibit intraguild predation; whereas, communities composed of strict predators and pathogens are more likely dominated by IGP dynamics. In these latter communities, the consumption of low and high quality resources suggests that IGP communities composed of strict predators, pathogens and prey should naturally persist, supporting IGP theory.

opencc-zeroDec 2013View details →

Data from: Using multiple imputation to estimate missing data in meta-regression

1. There is a growing need for scientific synthesis in ecology and evolution. In many cases, meta-analytic techniques can be used to complement such synthesis. However, missing data is a serious problem for any synthetic efforts and can compromise the integrity of meta-analyses in these and other disciplines. Currently, the prevalence of missing data in meta-analytic datasets in ecology and the efficacy of different remedies for this problem have not been adequately quantified. 2. We generated meta-analytic datasets based on literature reviews of experimental and observational data and found that missing data were prevalent in meta-analytic ecological datasets. We then tested the performance of complete case removal (a widely used method when data are missing) and multiple imputation (an alternative method for data recovery) and assessed model bias, precision, and multi-model rankings under a variety of simulated conditions using published meta-regression datasets. 3. We found that complete case removal led to biased and imprecise coefficient estimates and yielded poorly specified models. In contrast, multiple imputation provided unbiased parameter estimates with only a small loss in precision. The performance of multiple imputation, however, was dependent on the type of data missing. It performed best when missing values were weighting variables, but performance was mixed when missing values were predictor variables. Multiple imputation performed poorly when imputing raw data which was then used to calculate effect size and the weighting variable. 4. We conclude that complete case removal should not be used in meta-regression, and that multiple imputation has the potential to be an indispensable tool for meta-regression in ecology and evolution. However, we recommend that users assess the performance of multiple imputation by simulating missing data on a subset of their data before implementing it to recover actual missing data.

Data from: Patent foramen ovale closure, antiplatelet therapy or anticoagulation in patients with patent foramen ovale and cryptogenic stroke: a systematic review and network meta-analysis incorporating complementary external evidence

Objective: To examine the relative impact of three management options in patients less than 60 years old with cryptogenic stroke and a patent foramen ovale (PFO): PFO closure plus antiplatelet therapy, antiplatelet therapy alone, and anticoagulation alone. Design: Systematic review and network meta-analysis (NMA) supported by complementary external evidence Data sources: Medline, EMBASE, and Cochrane CENTRAL. Study selection: Randomised controlled trials (RCTs) addressing PFO closure and/or medical therapies in patients with PFO and cryptogenic stroke. Review methods: We conducted an NMA complemented with external evidence and rated certainty of evidence using the GRADE system. Results: Ten RCTs in eight studies proved eligible (n=4416). PFO closure versus antiplatelet therapy probably results in substantial reduction in ischaemic stroke recurrence (risk difference per 1000 patients over 5 years [RD]: -87, 95% credible interval [CrI] -100 to -33; moderate certainty). Compared with anticoagulation, PFO closure may confer little or no difference in ischaemic stroke recurrence (low certainty) but probably has a lower risk of major bleeding (RD -20, 95% Crl -27 to -2, moderate certainty). Relative to either medical therapy, PFO closure probably increases the risk of persistent atrial fibrillation (RD 18, CI +5 to +56, moderate certainty) and device-related adverse events (RD +36, 95% CI +23 to +50, high certainty). Anticoagulation, compared to antiplatelet therapy, may reduce the risk of ischaemic stroke recurrence (RD -71, 95% CrI -100 to +17, low certainty), but probably increases the risk of major bleeding (RD +12, CrI -5 to +65, moderate certainty). Conclusions: In patients less than 60 years old, PFO closure probably confers an important reduction in ischaemic stroke recurrence compared to antiplatelet therapy alone but may make no difference compared to anticoagulation. PFO closure incurs a risk of persistent atrial fibrillation and device-related adverse events. Compared to alternatives, anticoagulation probably increases major bleeding.

Data from: Ginkgo biloba extract for prevention of acute mountain sickness: a systematic review and meta-analysis of randomized controlled trials

Study objective: Trials of ginkgo biloba extract (GBE) for the prevention of acute mountain sickness (AMS) have been published since 1996. Because of their conflicting results, the efficacy of GBE remains unclear. We performed a systematic review and meta-analysis to assess whether GBE prevents acute mountain sickness. Methods: The Cochrane Library, EMBASE, Google Scholar, and PubMed databases were searched for articles published up to May 20, 2017. Only randomized controlled trials were included. AMS defined as acute mountain sickness–cerebral(AMS-C) score≧0.7 or Lake Louise Score (LLS)≧3 with headache. The main outcome measures were the relative risks of AMS in participants receiving GBE for prophylaxis. Meta-analyses were conducted using random-effects models. Sensitivity analyses, subgroup analyses and tests for publication bias were conducted. Results: Six published articles with a total of 451 participants met all eligibility criteria. In the primary meta-analysis of all 7 study groups, GBE showed trend of AMS prophylaxis, but it is not statistically significant (RR =0.68; 95% CI: 0.45 to 1.04; p-value=0.08) (Figure 2). The I2 statistic was 58.7% (p-value=0.02), indicating substantial heterogeneity. The results of subgroup analyses of studies with low risk of bias, low starting altitude (<2500 m), number of treatment days before ascending and dosage of GBE were similar. Conclusions: The currently available data suggest that although GBE may tend toward AMS prophylaxis, there are not enough data to show the statistically significant effect of GBE for preventing AMS. Further large randomized control studies are warranted.