Translucent windows: How uncertainty in competitive interactions impacts detection of community pattern

Trait variation and similarity among coexisting species can provide a window into the mechanisms that maintain their coexistence. Recent theoretical explorations suggest that competitive interactions will lead to groups, or clusters, of species with similar traits. However, theoretical predictions typically assume complete knowledge of the map between competition and measured traits. These assumptions limit the plausible application of these patterns for inferring competitive interactions in nature. Here we relax these restrictions and find that the clustering pattern is robust to contributions of unknown or unobserved niche axes. However, it may not be visible unless measured traits are close proxies for niche strategies. We conclude that patterns along single niche axes may reveal properties of interspecific competition in nature, but detecting these patterns requires natural history expertise firmly tying traits to niches.Comment: Main text: 18 pages, 6 figures. Appendices: A-G, 6 supplementary figures. This is the peer reviewed version of the article of the same title which has been accepted for publication at Ecology Letters. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archivin

A Novel UV Photon Detector with Resistive Electrodes

In this study we present first results from a new detector of UV photons: a thick gaseous electron multiplier (GEM) with resistive electrodes, combined with CsI or CsTe/CsI photocathodes. The hole type structure considerably suppresses the photon and ion feedback, whereas the resistive electrodes protect the detector and the readout electronics from damage by any eventual discharges. This device reaches higher gains than a previously developed photosensitive RPC and could be used not only for the imaging of UV sources, flames or Cherenkov light, for example, but also for the detection of X-rays and charged particles.Comment: Presented at the International Workshop on Resistive Plate Chambers, Korea, October 200

Under the spreading chestnut tree, accountants\u27 legal liability -- A historical perspective

https://egrove.olemiss.edu/dl_proceedings/1165/thumbnail.jp

TOLERANCE TO THE IMPAIRING EFFECTS OF ALCOHOL ON THE INHIBITION AND ACTIVATION OF BEHAVIOR

Moderate doses of alcohol impair response inhibition activation. Recent work has shown that, during a single dose, response inhibition recovers from the impairing effects of alcohol more slowly than response activation. Evidence for a lag in tolerance development to inhibitory versus activational mechanisms suggests that, as blood alcohol declines, drinkers’ response inhibition might continue to be impaired, despite the recovery of response activation. However, this has not been studied across repeated doses. This study examined how cross-session tolerance to alcohol develops differentially between response activation and inhibition. Thirty-two healthy adults performed a cued go/no-go task that measured response activation and inhibition. The study tested the degree to which response activation and inhibition developed acute and cross-session tolerance to a moderate dose of alcohol (0.65 g/kg) administered twice. Alcohol impaired response activation and inhibition during both administrations. Response activation displayed acute tolerance to alcohol during both administrations and cross-session tolerance from the first to second administration. Response inhibition was impaired by each alcohol administration but showed no acute or cross-session tolerance. Evidence of biased recovery of response activation over inhibition during a single dose and as doses are repeated could contribute to some of the impulsive behavior commonly observed under alcohol

Evaluation of Plasma Damage to Thin Gate Oxides

Capacitance-Voltage (C-V) arid Conductance-Voltage (G-V) measurements were performed to characterize field induced charges in thin (300A) oxides subjected to a RF generated oxygen plasma used to remove photoresist. Results based on C-V curves indicate a -4.6V threshold voltage shift for capacitors exposed to the RF plasma as compared to capacitors without plasma processing. Results based on tunnel current measurements were inconclusive

Biodiversity maintenance may be lower under partial niche differentiation than under neutrality

Niche differentiation is normally regarded as a key promoter of species coexistence in competitive systems. One might therefore expect that relative to neutral assemblages, niche‐differentiated communities should support more species with longer persistence and lower probability of extinction. Here we compare stochastic niche and neutral dynamics in simulated assemblages, and find that when local dynamics combine with immigration from a regional pool, the effect of niches can be more complex. Trait variation that lessens competition between species will not necessarily give all immigrating species their own niche to occupy. Such partial niche differentiation protects certain species from local extinction, but precipitates exclusion of others. Differences in regional abundances and intrinsic growth rates have similar impacts on persistence times as niche differentiation, and therefore blur the distinction between niche and neutral dynamical patterns—although niche dynamics will influence which species persist longer. Ultimately, unless the number of niches available to species is sufficiently high, niches may actually heighten extinction rates and lower species richness and local persistence times. Our results help make sense of recent observations of community dynamics, and point to the dynamical observations needed to discern the influence of niche differentiation.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140001/1/ecy2020-sup-0002-AppendixS2.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/140001/2/ecy2020_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/140001/3/ecy2020-sup-0001-AppendixS1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/140001/4/ecy2020.pd