Aim The abundant-centre hypothesis (ACH) is based on the assumption that physiological constraints limit populations at the edges of their distributional range, yet the geographical variation of physiological performance or life-history traits has rarely been examined. Here we examine the applicability of the ACH in a marine system by testing whether physiological predictions are reflected in large-scale variations of life-history traits.Location The Chilean coast (18°-42°S), encompassing more than 2500 km along the Pacific coast of South America.Methods Five porcelain crab species (Petrolisthes granulosus, Petrolisthes laevigatus, Petrolisthes tuberculatus, Petrolisthes violaceus and Allopetrolisthes angulosus) were sampled on intertidal boulder beaches at 13 sampling sites. For each species and site we evaluated: (1) relative abundance (density), (2) maximum size, (3) size at maturity, (4) sex ratio, (5) proportion of ovigerous females, and (6) presence of recruits. The shape of the spatial distribution of each trait was evaluated statistically against the prediction of four hypothetical models (normal, ramped-south, ramped-north and abundant-edge). ResultsThe relative abundance and life-history traits showed different spatial patterns among species. Relative abundance (across sites) was fitted by a normal model in only two species. No model fitted the spatial variation in body size and size at first maturity, which showed a slight but monotonic poleward increase in all species. Sex ratio showed a prominent hump-shaped pattern, with females prevailing in the centre of the ranges and males dominating towards the range boundaries; this pattern was statistically significant in three of the five studied species. The proportion of ovigerous females showed no clear latitudinal trends, and mature individuals were observed across most of the geographical range of the species. However, recruits tended to be absent towards the southern (poleward) boundaries of the distribution. Main conclusionsThe ACH does not apply to all species equally. The link between abundance and life-history traits is complex and variable among the porcelain crab species studied. Overall, the observed patterns were consistent with the idea that equatorward boundaries might be controlled by physiological restrictions mainly affecting adult survival, whereas poleward boundaries might be shaped by limitations in reproductive output and larval survival. Our results underline the importance of incorporating ecological, physiological and life-history studies in future tests of the ACH.
Expert Systems to Assist Analytical Chemistry: Troubleshooting and Plausibility Testing in Ion Chromatography An expert system for automated troubleshooting and plausibility testing in ion chromatography is introduced. The program is able to detect some major problems in the chromatograms. First it evaluates the incoming data to get the retention time, baseline drift and noise, the peakshape and other criteria. Based on this information conclusions are drawn whether an analysis is formally correct or not. Even more problems can be solved depending on the inputs of the users. The expert system is able to deal with many standard problems (523 are implemented). To evaluate the plausibility of the data the system uses known information about the sample (analytes and concentrations) to calculate ranges of credible results. The troubleshooting routines lead to at least 90% correct conclusions. The plausibility check needs many informations for the inference process, it succeeds best with routine problems.
Expert Systems to Assist Analytical Chemistry: Expert System NINA for Method Setup in Ion Chromatography An expert system for method setup in ion chromatography is introduced. It combines the features of method selection, so called „first guess”︁, with procedures for retention and selectivity optimization. The domain of ion chromatography is considered and structured from the point of view of an expert system. The necessary informations are gathered from various sources, and the parameters to characterize the important criteria for method setup are defined. Therefore, unique values, so called „Primzahläquivalente”︁, based on the multiplication of prime numbers are developed to describe all relevant aspects of the problem in only one variable. The knowledge is represented in databases and rulebases. The rules are built in „if ‐ then”︁ form and composed of declarations, exceptions and actions. They are combined with certainty factors to represent the probability and heuristics. Algorithms dealing with non monotone reasoning are used to find the solutions. An example for the problem solving mechanism of the expert system is given.
ZusammenfassungDeutschland hat die Umsetzung der Änderungsrichtlinie zur Vierten EU-Geldwäscherichtlinie zum Anlass genommen, im Alleingang die Verwahrung von Kryptowerten als Finanzdienstleistung einer Erlaubnispflicht nach dem KWG zu unterstellen. In der praktischen Rechtsanwendung zeigt sich jedoch, dass der Tatbestand des Kryptoverwahrgeschäfts nicht zuletzt durch die komplexe technische Materie eine Reihe von (Abgrenzungs-)Fragen aufwirft, die die Verwaltungs- und Beratungspraxis noch länger beschäftigen werden.
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