Does initial suppression of allofeeding in small jays help to conceal their nests?

2001 ◽  
Vol 79 (12) ◽  
pp. 2128-2146 ◽  
Author(s):  
Dan Strickland ◽  
Thomas A Waite
Keyword(s):  
Predator Avoidance ◽  
Meta Analysis ◽  
Indirect Evidence ◽  
Nest Area ◽  
Visitation Rates ◽  
Gray Jays ◽  
Parental Feeding ◽  
Perisoreus Canadensis ◽  
Parental Hostility ◽  
Late Stages

A neglected question in the study of communal breeding in birds concerns why alloparenting begins at variously late stages in the nesting cycle. We studied this phenomenon in the Gray Jay (Perisoreus canadensis), a species in which nonbreeders are excluded from the nest area by parental hostility and begin to feed young only during the fledgling period. We hypothesize that this pattern is favoured because of the risk of nest predation. By initially suppressing allofeeding, Gray Jay parents may reduce the frequency of predator-attracting visits to the nest when the young are most vulnerable. We evaluated this predator-avoidance hypothesis in a six-part meta-analysis using observations of 111 philopatric and immigrant nonbreeders associated with 647 pairs over 33 years and nest-visitation data for 307 other passerines. First, we found indirect evidence that Gray Jays and other corvids with non-allofeeding nonbreeders do reduce nest visitation by excluding nonbreeders. Second, we found that the hostility of adult Gray Jays towards nonbreeders peaks during the incubation and nestling periods, is stronger closer to the nest, and is directed towards both related and unrelated nonbreeders. We then found support for four predictions stemming from the predator-avoidance hypothesis. Compared with species having allofeeding nonbreeders, the Gray Jay and other corvids with non-allofeeding nonbreeders are characterized by (i) smaller clutches; (ii) lower parental nest-visitation rates (a consequence of larger food loads); (iii) a greater increase in parental feeding visits after fledging, paralleling the simultaneous relaxation of parental hostility towards potential allofeeders; and (iv) a smaller body size and smaller social groups, rendering them less able to deter nest predators. We discuss the potential value of the predator-avoidance perspective for understanding the occurrence or absence of allofeeding in other birds.

A test of the predator avoidance hypothesis to explain delayed onset of communal breeding

2019 ◽  
Vol 97 (4) ◽  
pp. 332-339
Author(s):  
D. Strickland ◽  
E. Brouwer ◽  
T.M. Burg
Keyword(s):  
Predator Avoidance ◽  
Group Living ◽  
Breeding Cycle ◽  
Communal Breeding ◽  
The Family ◽  
Perisoreus Canadensis ◽  
Insufficient Time ◽  
Anticosti Island ◽  
Free Environment ◽  
Late Stages

A neglected question in the study of communal breeding concerns why alloparental behaviour begins at variously late stages in the breeding cycle. In group-living corvids, the delay tends to be longer in species that are small and (or) typically have only a small nonbreeder complement. This pattern has been attributed to the relatively poor defensive capabilities of such species and their consequently greater need to minimize predator-attracting traffic to the nest or fledglings. We tested this predator avoidance hypothesis with the Canada Jay (Perisoreus canadensis (Linnaeus, 1766)), a species in which the feeding of young by any nonbreeders in the family group is delayed until the fledgling period. We reasoned that, on Anticosti Island, Quebec (Canada), in the absence of squirrels and other nest predators, nonbreeders might be permitted to feed nestlings as well as fledglings, and that breeders might feed nestlings more frequently (with smaller food loads) than on the mainland. We found no evidence for either prediction and thus no support for the predator avoidance hypothesis but suggest that Anticosti Canada Jays may have had insufficient time to evolve behaviour more appropriate for their predator-free environment. Secondarily, we confirmed that in all observed instances, the nonbreeders were offspring of the breeding pair from previous years and that they therefore failed to provision nestlings in spite of an apparent genetic interest to do so.

scholarly journals Conditional power of antidepressant network meta-analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lisa Holper
Keyword(s):  
Meta Analysis ◽  
Indirect Evidence ◽  
Dropout Rate ◽  
Conclusive Evidence ◽  
Effect Sizes ◽  
Current Evidence ◽  
Hamilton Depression Scale ◽  
Conditional Power ◽  
Sample Sizes ◽  
Antidepressant Treatments

Abstract Background Conditional power of network meta-analysis (NMA) can support the planning of randomized controlled trials (RCTs) assessing medical interventions. Conditional power is the probability that updating existing inconclusive evidence in NMA with additional trial(s) will result in conclusive evidence, given assumptions regarding trial design, anticipated effect sizes, or event probabilities. Methods The present work aimed to estimate conditional power for potential future trials on antidepressant treatments. Existing evidence was based on a published network of 502 RCTs conducted between 1979-2018 assessing acute antidepressant treatment in major depressive disorder (MDD). Primary outcomes were efficacy in terms of the symptom change on the Hamilton Depression Scale (HAMD) and tolerability in terms of the dropout rate due to adverse events. The network compares 21 antidepressants consisting of 231 relative treatment comparisons, 164 (efficacy) and 127 (tolerability) of which are currently assumed to have inconclusive evidence. Results Required sample sizes to achieve new conclusive evidence with at least 80% conditional power were estimated to range between N = 894 - 4190 (efficacy) and N = 521 - 1246 (tolerability). Otherwise, sample sizes ranging between N = 49 - 485 (efficacy) and N = 40 - 320 (tolerability) may require stopping for futility based on a boundary at 20% conditional power. Optimizing trial designs by considering multiple trials that contribute both direct and indirect evidence, anticipating alternative effect sizes or alternative event probabilities, may increase conditional power but required sample sizes remain high. Antidepressants having the greatest conditional power associated with smallest required sample sizes were identified as those on which current evidence is low, i.e., clomipramine, levomilnacipran, milnacipran, nefazodone, and vilazodone, with respect to both outcomes. Conclusions The present results suggest that conditional power to achieve new conclusive evidence in ongoing or future trials on antidepressant treatments is low. Limiting the use of the presented conditional power analysis are primarily due to the estimated large sample sizes which would be required in future trials as well as due to the well-known small effect sizes in antidepressant treatments. These findings may inform researchers and decision-makers regarding the clinical relevance and justification of research in ongoing or future antidepressant RCTs in MDD.

scholarly journals Comparison of the clinical effectiveness of treatments for aromatase inhibitor-induced arthralgia in breast cancer patients: a protocol for a systematic review and network meta-analysis

BMJ Open ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. e033461
Author(s):  
Kyeore Bae ◽  
Si Yeon Song
Keyword(s):  
Breast Cancer ◽  
Systematic Review ◽  
Pain Intensity ◽  
Aromatase Inhibitor ◽  
Cancer Patients ◽  
Meta Analysis ◽  
Indirect Evidence ◽  
Secondary Outcome ◽  
Breast Cancer Patients ◽  
Patient Reported

IntroductionAromatase inhibitor-induced arthralgia (AIA) is a major adverse event of aromatase inhibitors (AIs) and leads to premature discontinuation of AI therapy in breast cancer patients. The objective of this protocol for a systematic review and network meta-analysis (NMA) is to provide the methodology to compare the change in pain intensity between different AIA treatments and demonstrate the rank probabilities for different treatments by combining all available direct and indirect evidence.Methods and analysisPubMed, the Cochrane Controlled Register of Trials (CENTRAL), EMBASE, Web of Science and ClinicalTrials.gov will be searched to identify publications in English from inception to November 2019. We will include randomised controlled trials (RCTs) assessing the effects of different treatments for AIA in postmenopausal women with stage 0–III hormone receptor-positive breast cancer. The primary endpoints will be the change in patient-reported pain intensity from baseline to post-treatment. The number of adverse events will be presented as a secondary outcome.Both pairwise meta-analysis and NMA with the Frequentist approach will be conducted. We will demonstrate summary estimates with forest plots in meta-analysis and direct and mixed evidence with a ranking of the treatments as the P-score in NMA. The revised Cochrane risk-of-bias tool for randomised trials will be used to assess the methodological quality within individual RCTs. The quality of evidence will be assessed.Ethics and disseminationAs this review does not involve individual patients, ethical approval is not required. The results of this systematic review and NMA will be published in a peer-reviewed journal. This review will provide valuable information on AIA therapeutic options for clinicians, health practitioners and breast cancer survivors.PROSPERO registration numberCRD42019136967.

scholarly journals Deriving percentage study weights in multi-parameter meta-analysis models: with application to meta-regression, network meta-analysis and one-stage individual participant data models

2017 ◽  
Vol 27 (10) ◽  
pp. 2885-2905 ◽  
Author(s):  
Richard D Riley ◽  
Joie Ensor ◽  
Dan Jackson ◽  
Danielle L Burke
Keyword(s):  
Meta Analysis ◽  
Information Matrix ◽  
Indirect Evidence ◽  
Parameter Estimates ◽  
Individual Participant Data ◽  
One Stage ◽  
Individual Participant ◽  
Meta Regression ◽  
Multiple Treatments ◽  
Analysis Models

Many meta-analysis models contain multiple parameters, for example due to multiple outcomes, multiple treatments or multiple regression coefficients. In particular, meta-regression models may contain multiple study-level covariates, and one-stage individual participant data meta-analysis models may contain multiple patient-level covariates and interactions. Here, we propose how to derive percentage study weights for such situations, in order to reveal the (otherwise hidden) contribution of each study toward the parameter estimates of interest. We assume that studies are independent, and utilise a decomposition of Fisher’s information matrix to decompose the total variance matrix of parameter estimates into study-specific contributions, from which percentage weights are derived. This approach generalises how percentage weights are calculated in a traditional, single parameter meta-analysis model. Application is made to one- and two-stage individual participant data meta-analyses, meta-regression and network (multivariate) meta-analysis of multiple treatments. These reveal percentage study weights toward clinically important estimates, such as summary treatment effects and treatment-covariate interactions, and are especially useful when some studies are potential outliers or at high risk of bias. We also derive percentage study weights toward methodologically interesting measures, such as the magnitude of ecological bias (difference between within-study and across-study associations) and the amount of inconsistency (difference between direct and indirect evidence in a network meta-analysis).

scholarly journals Comparing pharmacological venous thromboembolism prophylaxis to intermittent pneumatic compression in acute intracerebral haemorrhage: protocol for a systematic review and network meta-analysis

BMJ Open ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. e024405 ◽  
Author(s):  
Vignan Yogendrakumar ◽  
Ronda Lun ◽  
Brian Hutton ◽  
Dean A Fergusson ◽  
Dar Dowlatshahi
Keyword(s):  
Systematic Review ◽  
Venous Thromboembolism ◽  
Intracerebral Haemorrhage ◽  
Meta Analysis ◽  
Indirect Evidence ◽  
Intermittent Pneumatic Compression ◽  
Qualitative Assessment ◽  
Primary Data ◽  
Thromboembolism Prophylaxis ◽  
Increased Risk

IntroductionPatients with an intracerebral haemorrhage are at increased risk of venous thromboembolism. Pharmacotherapy and pneumatic compression devices are capable of preventing venous thromboembolism, however both interventions have limitations. There are no head-to-head comparisons between these two interventions. To address this knowledge gap, we plan to perform a systematic review and network meta-analysis to examine the comparative effectiveness of pharmacological prophylaxis and mechanical compression devices in the context of intracerebral haemorrhage.Methods and analysisMEDLINE, PUBMED, EMBASE, CENTRAL, ClinicalTrials.gov and the Internet Stroke Trials Registry will be searched with assistance from an experienced information specialist. Eligible studies will include those that have enrolled adults presenting with spontaneous intracerebral haemorrhage and compared one or more of the respective interventions against each other and/or a control. Primary outcomes to be assessed are occurrence of new venous thromboembolism (deep vein thrombosis and/or pulmonary embolism) and haematoma expansion, defined as a significant enlargement of baseline haemorrhage or new haemorrhage occurrence. Both randomised and non-randomised comparative studies will be included. Data on participant characteristics, study design, intervention details and outcomes will be extracted. Study quality will be assessed using the Cochrane Risk of Bias Tool and the Robins-I tool. Bayesian network meta-analyses will be performed to compare interventions based on all available direct and indirect evidence. If the transitivity assumption for network meta-analysis cannot be met, we will perform a qualitative assessment.Ethics and disseminationFormal ethics is not required as primary data will not be collected. The findings of this study will be disseminated through conference presentations, and peer-reviewed publications. In an area of clinical practice where equipoise exists, the findings of this study may assist in determining which treatment intervention is most effective in venous thromboembolism prevention.PROSPERO registration numberCRD42018090960.

Erroneous choice and foregone gains in hoarding gray jays ( Perisoreus canadensis )

2000 ◽  
Vol 3 (3) ◽  
pp. 127-134 ◽  
Author(s):  
T. A. Waite ◽  
K. L. Field
Keyword(s):  
Gray Jays ◽  
Perisoreus Canadensis

scholarly journals Obesity and Periodontal Disease: A Narrative Review on Current Evidence and Putative Molecular Links

2019 ◽  
Vol 13 (1) ◽  
pp. 526-536
Author(s):  
Federica Di Spirito ◽  
Ludovico Sbordone ◽  
Vincenzo Pilone ◽  
Francesco D’Ambrosio
Keyword(s):  
Periodontal Disease ◽  
Systematic Reviews ◽  
Literature Search ◽  
Meta Analysis ◽  
Indirect Evidence ◽  
Positive Association ◽  
Current Evidence ◽  
Screening Process ◽  
Clinical Criteria ◽  
Comparison Of The Results

Background: Obesity represents one of the main health problems worldwide and is considered a risk factor for several diseases, including periodontitis, which is a microbially-associated inflammatory disease affecting the tooth-supporting structures. Objective: The aim of this review was to report the current direct and indirect evidence concerning the possible association between obesity and periodontitis and their putative molecular links. Methods: A literature search was conducted between January 1999 and September 2019, in PubMed/MEDLINE and Science Direct databases, using pertinent keyword combined by Boolean operators. Through a multi-step screening process (literature search; articles title and abstract evaluation and full-text reading), studies fitting inclusion/exclusion criteria were considered for the review. Results: 35 studies were included in the present review (17 observational studies; 7 systematic reviews; 11 systematic reviews with meta-analysis), focusing on the direct and indirect evidence of the possible association between obesity and periodontitis and their potential etiopathogenic molecular links Conclusion: Although the majority of the studies reported a positive association between obesity and periodontitis, the heterogeneity of the classification criteria and of the clinical parameters employed in the studies for both obesity and periodontitis evaluation, complicated the comparison of the results, thus considered inconclusive. Although several putative molecular pathogenic links between obesity and periodontitis have been highlighted, further studies, with longer follow-ups and with homogeneous clinical criteria, are needed to better understand the putative relation between obesity and periodontal disease.

scholarly journals Planning a future randomized clinical trial based on a network of relevant past trials

2018 ◽  
Author(s):  
Georgia Salanti ◽  
Adriani Nikolakopoulou ◽  
Alex J Sutton ◽  
Stephan Reichenbach ◽  
Sven Trelle ◽  
...  
Keyword(s):  
Trial Design ◽  
Randomized Clinical Trials ◽  
Guideline Development ◽  
Meta Analysis ◽  
Indirect Evidence ◽  
Public Health Decision ◽  
Relapsing Remitting ◽  
Health Decision ◽  
Meta Analyses ◽  
Relapsing Remitting Multiple Sclerosis

ABSTRACTBackground: The important role of network meta-analysis of randomized clinical trials in health technology assessment and guideline development is increasingly recognized. This approach has the potential to obtain conclusive results earlier than with new standalone trials or conventional, pairwise meta-analyses.Methods: Network meta-analyses can also be used to plan future trials. We introduce a four-steps framework to plan a new trial that aims to identify the optimal new design that will update the existing evidence to best serve timely clinical and public health decision making. The new trial designed within this framework does not need to include all competing interventions and comparisons of interest and can contribute direct and indirect evidence to the updated network meta-analysis. We present the method by virtually planning a new trial to compare biologics in rheumatoid arthritis and a new trial to compare two drugs for relapsing-remitting multiple sclerosis.Results: A trial design based on updating the evidence from a network meta-analysis of relevant previous trials may require a considerably smaller sample size to reach the same conclusion compared with a trial designed and analyzed in isolation. Challenges in the approach include the complexity of the methodology and the need for a coherent network meta-analysis of previous trials with little heterogeneity.Conclusions: When used judiciously, conditional trial design could significantly reduce waste in clinical research.

scholarly journals A Likelihood Ratio Test For The Homogeneity of Between-Study Variance in Network Meta-Analysis

2021 ◽  
Author(s):  
Dapeng Hu ◽  
Chong Wang ◽  
Annette O'Connor
Keyword(s):  
Likelihood Ratio ◽  
Likelihood Ratio Test ◽  
Random Effects ◽  
Type I Error ◽  
Meta Analysis ◽  
Indirect Evidence ◽  
Point Estimate ◽  
Ratio Test ◽  
Type I ◽  
Statistical Heterogeneity

Abstract Background: Network meta-analysis (NMA) is a statistical method used to combine results from several clinical trials and simultaneously compare multiple treatments using direct and indirect evidence. Statistical heterogeneity is a characteristic describing the variability in the intervention effects being evaluated in the different studies in network meta-analysis. One approach to dealing with statistical heterogeneity is to perform a random effects network meta-analysis that incorporates a between-study variance into the statistical model. A common assumption in the random effects model for network meta-analysis is the homogeneity of between-study variance across all interventions. However, there are applications of NMA where the single between-study assumption is potentially incorrect and instead the model should incorporate more than one between-study variances. Methods: In this paper, we develop an approach to testing the homogeneity of between-study variance assumption based on a likelihood ratio test. A simulation study was conducted to assess the type I error and power of the proposed test. This method is then applied to a network meta-analysis of antibiotic treatments for Bovine respiratory disease (BRD). Results: The type I error rate was well controlled in the Monte Carlo simulation. The homogeneous between-study variance assumption is unrealistic both statistically and practically in the network meta-analysis BRD. The point estimate and conffdence interval of relative effect sizes are strongly inuenced by this assumption. Conclusions: Since homogeneous between-study variance assumption is a strong assumption, it is crucial to test the validity of this assumption before conducting a network meta-analysis. Here we propose and validate a method for testing this single between-study variance assumption which is widely used for many NMA.

scholarly journals Efficacy and Toxicity of Different Concurrent Chemoradiotherapy Regimens in Patients With Locally Advanced Non-Small Cell Lung Cancer-a Network Meta-Analysis­

2021 ◽  
Author(s):  
Qiang-qiang Zheng ◽  
Shi-hui Min ◽  
Qing-hua Zhou
Keyword(s):  
Lung Cancer ◽  
Small Cell Lung Cancer ◽  
Cell Lung Cancer ◽  
Concurrent Chemoradiotherapy ◽  
Meta Analysis ◽  
Locally Advanced ◽  
Indirect Evidence ◽  
Small Cell ◽  
Cochrane Central Register ◽  
Small Cell Lung

Abstract Background: Concurrent chemoradiotherapy (CCRT) is the cornerstone treatment for patients with locally advanced non-small cell lung cancer (LA-NSCLC). The aim of this study was to compare the efficacy and toxicity of different CCRT regimens in the treatment of LA-NSCLC by adopting a network meta-analysis.Methods: PubMed, EMBASE, Web of Science, and the Cochrane Central Register of Controlled Trials (CENTRAL) were exhaustively searched to identify relevant studies from inception up to October 1, 2020. Direct and indirect evidence were combined to calculate the odds radio (OR) and its 95% confidence interval (CI), as well as to draw the surface under the cumulative ranking (SUCRA) curves. Cluster analyses were adopted to compare efficacy and toxicity of different CCRT regimens according to the similarity of 2 variables. Publication bias was detected by comparison-adjusted funnel plot.Results: Twenty-two studies were enrolled in this network meta-analysis, including 18 CCRT regimens: CCRT (cisplatin+etoposide), CCRT (carboplatin+paclitaxel), CCRT (pemetrexed+carboplatin), CCRT (pemetrexed+cisplatin), CCRT (docetaxel+cisplatin), CCRT (S-1+cisplatin), CCRT (mitomycin+vindesine+cisplatin), CCRT (cisplatin+vinorelbine), CCRT (cisplatin), CCRT (etoposide+cisplatin+amifostine), RT, CCRT (5-FU), CCRT (paclitaxel+cisplatin), CCRT (irinotecan+carboplatin), CCRT (nedaplatin), CCRT (carboplatin+etoposide), CCRT (paclitaxel), and CCRT (carboplatin). The results indicated that the regimens with CCRT (cisplatin+etoposide), CCRT (carboplatin+paclitaxel), CCRT (pemetrexed+cisplatin), CCRT (S-1+cisplatin), and CCRT (cisplatin+vinorelbine) had relatively better efficacy compared with other regimens. As for toxicity of different CCRT regimens, the CCRT (carboplatin+paclitaxel), CCRT (pemetrexed+cisplatin), and CCRT (docetaxel+cisplatin) were relatively lower.Conclusions: Our study demonstrated that CCRT (pemetrexed+cisplatin) and CCRT (carboplatin+paclitaxel) might be the best choice of CCRT regimens in the treatment of LA-NSCLC, and the 3-year overall survival (OS) rate of CCRT (pemetrexed+cisplatin) was the highest among these regimens.

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