@article{HoulahanCurrieCottenieetal.2007, author = {Houlahan, Jeff E. and Currie, David J. and Cottenie, Karl and Cumming, Graeme S. and Ernest, S. K. Morgan and Findlay, C. Scott and Fuhlendorf, Samuel D. and Gaedke, Ursula and Legendre, Pierre and Magnuson, John J. and McArdle, Brian H. and Muldavin, Esteban H. and Noble, David and Russell, Robert and Stevens, Richard D. and Willis, Trevor J. and Woiwod, Ian P. and Wondzell, Steve M.}, title = {Compensatory dynamics are rare in natural ecological communities}, issn = {0027-8424}, doi = {10.1073/pnas.0603798104}, year = {2007}, abstract = {In population ecology, there has been a fundamental controversy about the relative importance of competition- driven (density-dependent) population regulation vs. abiotic influences such as temperature and precipitation. The same issue arises at the community level; are population sizes driven primarily by changes in the abundances of cooccurring competitors (i.e., compensatory dynamics), or do most species have a common response to environmental factors? Competitive interactions have had a central place in ecological theory, dating back to Gleason, Volterra, Hutchison and MacArthur, and, more recently, Hubbell's influential unified neutral theory of biodiversity and biogeography. If competitive interactions are important in driving year-to-year fluctuations in abundance, then changes in the abundance of one species should generally be accompanied by compensatory changes in the abundances of others. Thus, one necessary consequence of strong compensatory forces is that, on average, species within communities will covary negatively. Here we use measures of community covariance to assess the prevalence of negative covariance in 41 natural communities comprising different taxa at a range of spatial scales. We found that species in natural communities tended to covary positively rather than negatively, the opposite of what would be expected if compensatory dynamics were important. These findings suggest that abiotic factors such as temperature and precipitation are more important than competitive interactions in driving year-to-year fluctuations in species abundance within communities.}, language = {en} } @article{HeneghanWardPereraetal.2012, author = {Heneghan, Carl and Ward, Alison and Perera, Rafael and Bankhead, Clare and Fuller, Alice and Stevens, Richard and Bradford, Kairen and Tyndel, Sally and Alonso-Coello, Pablo and Ansell, Jack and Beyth, Rebecca and Bernardo, Artur and Christensen, Thomas Decker and Cromheecke, Manon and Edson, Robert G and Fitzmaurice, David and Gadisseur, Alain PA and Garcia-Alamino, Josep M and Gardiner, Chris and Hasenkam, Michael and Jacobson, Alan and Kaatz, Scott and Kamali, Farhad and Khan, Tayyaba Irfan and Knight, Eve and Kortke, Heinrich and Levi, Marcel and Matchar, David Bruce and Menendez-Jandula, Barbara and Rakovac, Ivo and Schaefer, Christian and Siebenhofer, Andrea and Souto, Juan Carlos and Sunderji, Rubina and Gin, Kenneth and Shalansky, Karen and V{\"o}ller, Heinz and Wagner, Otto and Zittermann, Armin}, title = {Self-monitoring of oral anticoagulation systematic review and meta-analysis of individual patient data}, series = {The lancet}, volume = {379}, journal = {The lancet}, number = {9813}, publisher = {Elsevier}, address = {New York}, organization = {Self-Monitoring Trialist Collabora}, issn = {0140-6736}, doi = {10.1016/S0140-6736(11)61294-4}, pages = {322 -- 334}, year = {2012}, abstract = {Background Uptake of self-testing and self-management of oral coagulation has remained inconsistent, despite good evidence of their effectiveness. To clarify the value of self-monitoring of oral anticoagulation, we did a meta-analysis of individual patient data addressing several important gaps in the evidence, including an estimate of the effect on time to death, first major haemorrhage, and thromboembolism. Methods We searched Ovid versions of Embase (1980-2009) and Medline (1966-2009), limiting searches to randomised trials with a maximally sensitive strategy. We approached all authors of included trials and requested individual patient data: primary outcomes were time to death, first major haemorrhage, and first thromboembolic event. We did prespecified subgroup analyses according to age, type of control-group care (anticoagulation-clinic care vs primary care), self-testing alone versus self-management, and sex. We analysed patients with mechanical heart valves or atrial fibrillation separately. We used a random-effect model method to calculate pooled hazard ratios and did tests for interaction and heterogeneity, and calculated a time-specific number needed to treat. Findings Of 1357 abstracts, we included 11 trials with data for 6417 participants and 12 800 person-years of follow-up. We reported a significant reduction in thromboembolic events in the self-monitoring group (hazard ratio 0.51; 95\% CI 0.31-0.85) but not for major haemorrhagic events (0.88, 0.74-1.06) or death (0.82, 0.62-1.09). Participants younger than 55 years showed a striking reduction in thrombotic events (hazard ratio 0.33, 95\% CI 0.17-0.66), as did participants with mechanical heart valve (0.52, 0.35-0.77). Analysis of major outcomes in the very elderly (age >= 85 years, n=99) showed no significant adverse effects of the intervention for all outcomes. Interpretation Our analysis showed that self-monitoring and self-management of oral coagulation is a safe option for suitable patients of all ages. Patients should also be offered the option to self-manage their disease with suitable health-care support as back-up.}, language = {en} }