643 research outputs found
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Game of Tenure: the role of “hidden” citations on researchers’ ranking in Ecology
Field ecologists and macroecologists often compete for the same grants and academic positions, with the former producing primary data that the latter generally use for model parameterization. Primary data are usually cited only in the supplementary materials, thereby not counting formally as citations, creating a system where field ecologists are routinely under-acknowledged and possibly disadvantaged in the race for funding and positions. Here, we explored how the performance of authors producing novel ecological data would change if all the citations to their work would be accounted for by bibliometric indicators. We collected the track record of >2300 authors from Google Scholar and citation data from 600 papers published in 40 ecology journals, including field-based, conservation, general ecology, and macroecology studies. Then we parameterized a simulation that mimics the current publishing system for ecologists and assessed author rankings based on number of citations, H-Index, Impact Factor, and number of publications under a scenario where supplementary citations count. We found weak evidence for field ecologists being lower ranked than macroecologists or general ecologists, with publication rate being the main predictor of author performance. Current ranking dynamics were largely unaffected by supplementary citations as they are 10 times less than the number of main text citations. This is further exacerbated by the common practice of citing datasets assembled by previous research or data papers instead of the original articles. While accounting for supplementary citations does not appear to offer a solution, researcher performance evaluations should include criteria that better capture authors’ contribution of new, publicly available data. This could encourage field ecologists to collect and store new data in a systematic manner, thereby mitigating the data patchiness and bias in macroecology studies, and further accelerating the advancement of ecology and related areas of biogeography
The influence of stochasticity, landscape structure and species traits on abundant–centre relationships
© 2020 The Authors. Ecography published by John Wiley & Sons Ltd on behalf of Nordic Society Oikos Species have been commonly hypothesized to have high population densities in geographic areas which correspond to either the centre of the species geographic range or climatic niche (abundant–centre hypothesis). However, there is mixed empirical support for this relationship, and little theoretical underpinning. We simulate a species spreading across a set of replicated artificial landscapes to examine the expected level of support for abundant–centre relationships in geographic and niche space. Species niche constraints were modeled as a single axis which was related directly to population growth rates. We found strong evidence for abundant–centre relationships when populations follow deterministic growth, dispersal is high, environmental noise is absent and intraspecific competition is low. However, the incorporation of ecological realism reduced the detectability of abundant–centre relationships considerably. Our results suggest that even in carefully constructed artificial landscapes designed to demonstrate abundant–centre dynamics, the incorporation of small amounts of demographic stochasticity, environmental heterogeneity or landscape structure can strongly influence the relationship between species population density and distance to species geographic range or niche centre. While some simulated relationships were of comparable strength to common empirical support for abundant–centre relationships, our results suggest that these relationships are expected to be fairly variable and weak
Esophageal Electrical Cardioversion of Atrial Fibrillation: When Esophagus Gives a Help to Cardiologists
Atrial fibrillation is a common clinical disease especially in the elderly and in patients with organic heart disease. Electrical cardioversion is the first choice therapeutic approach for patients in which sinus rhythm could improve the quality of life and where the maintenance of sinus rhythm is considered likely. There are different techniques to perform an electrical cardioversion, each with specific indications, advantages, and limitations. The method most frequently used to restore sinus rhythm is external direct current cardioversion; however, this technique has some disadvantages, since it requires a high energy and usually general anesthesia. Esophageal cardioversion is an alternative method to obtain restoration of sinus rhythm, warranting acute and long-term results absolutely comparable with those obtained by the conventional transthoracic technique, especially in obese and COPD patients with high thoracic impedance for whom the standard technique may be less effective
Spreading of a local excitation in a Quantum Hierarchical Model
We study the dynamics of the quantum Dyson hierarchical model in its
paramagnetic phase. An initial state made by a local excitation of the
paramagnetic ground state is considered. We provide analytical predictions for
its time evolution, solving the single-particle dynamics on a hierarchical
network. A localization mechanism is found and the excitation remains close to
its initial position at arbitrary times. Furthermore, a universal scaling among
space and time is found related to the algebraic decay of the interactions as
. We compare our predictions to numerics, employing tensor
network techniques, for large magnetic fields, discussing the robustness of the
mechanism in the full many-body dynamics
A comparison of population viability measures
The viability of populations can be quantified with several measures, such as the probability of extinction, the mean time to extinction, or the population size. While conservation management decisions can be based on these measures, it has not yet been explored systematically if different viability measures rank species and scenarios similarly and if one viability measure can be converted into another to compare studies. To address this challenge, we conducted a quantitative comparison of eight viability measures based on the simulated population dynamics of more than 4500 virtual species. We compared (a) the ranking of scenarios based on different viability measures, (b) assessed direct correlations between the measures, and (c) explored if parameters in the simulation models can alter the relationship between pairs of viability measures. We found that viability measures ranked species similarly. Despite this, direct correlations between the different measures were often weak and could not be generalized. This can be explained by the loss of information due to the aggregation of raw data into a single number, the effect of model parameters on the relationship between viability measures, and because distributions, such as the probability of extinction over time, cannot be ranked objectively. Similar scenario rankings by different viability measures show that the choice of the viability metric does in many cases not alter which population is regarded more viable or which management option is the best. However, the more two scenarios or populations differ, the more likely it becomes that different measures produce different rankings. We thus recommend that PVA studies publish raw simulation data, which not only describes all risks and opportunities to the reader but also facilitates meta-analyses of PVA studies
Correction: Quantum error correction with molecular spin qudits
Correction for 'Quantum error correction with molecular spin qudits' by Mario Chizzini et al., Phys. Chem. Chem. Phys., 2022, https://doi.org/10.1039/D2CP01228F
Climate Change and Geographic Ranges: The Implications for Russian Forests
Forest ecosystems of the Russian Federation are expected to face high risks under environmental dynamics related to climate change. Analyzing the likely impacts of climate change on forest ecosystems is crucial in order to understand the potential adaptation of forests, to guide management strategies, as well as to preserve ecosystem services. With the aim to provide information on the possible modifications of geographic ranges, in the medium to long-term, for some Russian dominant forest species under climate change, we applied a Cascade Ensemble System (CES) approach. This consists of combining Ensemble Platform for Species Distribution Models (SDMs) to six bias-corrected Earth System Model (ESM) projections, driven in turn by two Representative Concentration Pathways (RCPs) proxies of greenhouse gas emission scenarios, in order to obtain area maps of the future suitability for forest species. The suitability information is then flagged with information about its “likelihood,” adopting the IPCC terminology based on a consensus among projections. Maps of aggregated changes were created in order to identify areas potentially more vulnerable to climate change. Results showed that possible impacts of climate change (either gain or loss) were diversified across species with a pronounced Northward shift of the ranges. Further analyses were performed at sub-regional levels revealing the potential for the Arctic Circle to become a refuge area for some conifer species. Species-aggregated change analyses spotted two distinct areas as more vulnerable to habitat change, in the central and south-east portions of the Russian territory. Our findings represent useful and immediate biogeographical information available to Russian policy makers to delineate conservation strategies and forest management plans
A trait-based approach for predicting species responses to environmental change from sparse data : how well might terrestrial mammals track climate change?
Acknowledgements LS was supported by two STSMs by the COST Action ES1101 ”Harmonising Global Biodiversity Modelling“ (Harmbio), supported by COST (European Cooperation in Science and Technology). JMB and SMW were funded by CEH projects NEC05264 and NEC05100. JMJT and SCFP are grateful for the support of the Natural Environment Research Council UK (NE/J008001/1). LS, JAH and JMJT conceived the original idea. LS, JAH, JMB, TC & JMJT designed the study; LS collected the data; LS and TC performed the statistical analyses; LS conducted the integrodifference modelling assisted by JMB and SMW. LS conducted the individual-based modelling assisted by SCFP. LS led the writing supported by JMJT, JMB, SCFP, SMW, TC, JAH and GB.Peer reviewedPublisher PD
Rapid Anthropocene realignment of allometric scaling rules
The negative relationship between body size and population density in mammals is often interpreted as resulting from energetic constraints. In a global change scenario, however, this relationship might be expected to change, given the size-dependent nature of anthropogenic pressures and vulnerability to extinction. Here we test whether the size-density relationship (SDR) in mammals has changed over the last 50 years. We show that the relationship has shifted down and became shallower, corresponding to a decline in population density of 31–73%, for the largest and smallest mammals, respectively. However, the SDRs became steeper in some groups (e.g. carnivores) and shallower in others (e.g. herbivores). The Anthropocene reorganisation of biotic systems is apparent in macroecological relationships, reinforcing the notion that biodiversity pattens are contingent upon conditions at the time of investigation. We call for an increased attention to the role of global change on macroecological inferences
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