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

Emergent neutrality or hidden niches?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/100274/1/j.1600-0706.2013.00298.x.pd

Counting niches: Abundance- by- trait patterns reveal niche partitioning in a Neotropical forest

Tropical forests challenge us to understand biodiversity, as numerous seemingly similar species persist on only a handful of shared resources. Recent ecological theory posits that biodiversity is sustained by a combination of species differences reducing interspecific competition and species similarities increasing time to competitive exclusion. Together, these mechanisms counterintuitively predict that competing species should cluster by traits, in contrast with traditional expectations of trait overdispersion. Here, we show for the first time that trees in a tropical forest exhibit a clustering pattern. In a 50- ha plot on Barro Colorado Island in Panama, species abundances exhibit clusters in two traits connected to light capture strategy, suggesting that competition for light structures community composition. Notably, we find four clusters by maximum height, quantitatively supporting the classical grouping of Neotropical woody plants into shrubs, understory, midstory, and canopy layers.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155460/1/ecy3019.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155460/2/ecy3019-sup-0001-AppendixS1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155460/3/ecy3019_am.pd

Dual Amplified Spontaneous Emission and Lasing from Nanographene Films

Chemically synthesized zigzag-edged nanographenes (NG) have recently demonstrated great success as the active laser units in solution-processed organic distributed feedback (DFB) lasers. Here, we report the first observation of dual amplified spontaneous emission (ASE) from a large-size NG derivative (with 12 benzenoid rings) dispersed in a polystyrene film. ASE is observed simultaneously at the 685 and 739 nm wavelengths, which correspond to different transitions of the photoluminescence spectrum. Ultrafast pump-probe spectroscopy has been used to ascertain the underlying photophysical processes taking place in the films. DFB lasers, based on these materials and top-layer nanostructured polymeric resonators (i.e., one or two-dimensional surface relief gratings), have been fabricated and characterized. Lasers emitting close to either one of the two possible ASE wavelengths, or simultaneously at both of them, have been prepared by proper selection of the resonator parameters.The Alicante team was funded by Spanish Government (MINECO) and European Community (FEDER), grant number MAT2015-66586-R. The researcher R.M-M was funded by a MINECO FPI fellowship (No. BES-2016-077681). The Singapore team was funded by the NRF Investigatorship programme (NRF-NRFI05-2019-0005). The Milan team has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 816313). G.M.P. acknowledges funding from Fondazione Cariplo, grant No. 2018-0979. C.D. and S.S. acknowledge funding from ERC Starting Grant SOLENALGAE (No. 679814)

The Baryon Oscillation Spectroscopic Survey of SDSS-III

The Baryon Oscillation Spectroscopic Survey (BOSS) is designed to measure the scale of baryon acoustic oscillations (BAO) in the clustering of matter over a larger volume than the combined efforts of all previous spectroscopic surveys of large scale structure. BOSS uses 1.5 million luminous galaxies as faint as i=19.9 over 10,000 square degrees to measure BAO to redshifts z<0.7. Observations of neutral hydrogen in the Lyman alpha forest in more than 150,000 quasar spectra (g<22) will constrain BAO over the redshift range 2.15<z<3.5. Early results from BOSS include the first detection of the large-scale three-dimensional clustering of the Lyman alpha forest and a strong detection from the Data Release 9 data set of the BAO in the clustering of massive galaxies at an effective redshift z = 0.57. We project that BOSS will yield measurements of the angular diameter distance D_A to an accuracy of 1.0% at redshifts z=0.3 and z=0.57 and measurements of H(z) to 1.8% and 1.7% at the same redshifts. Forecasts for Lyman alpha forest constraints predict a measurement of an overall dilation factor that scales the highly degenerate D_A(z) and H^{-1}(z) parameters to an accuracy of 1.9% at z~2.5 when the survey is complete. Here, we provide an overview of the selection of spectroscopic targets, planning of observations, and analysis of data and data quality of BOSS.Comment: 49 pages, 16 figures, accepted by A

The Baryon Oscillation Spectroscopic Survey of SDSS-III

The Baryon Oscillation Spectroscopic Survey (BOSS) is designed to measure the scale of baryon acoustic oscillations (BAO) in the clustering of matter over a larger volume than the combined efforts of all previous spectroscopic surveys of large-scale structure. BOSS uses 1.5 million luminous galaxies as faint as i = 19.9 over 10,000 deg(2) to measure BAO to redshifts z < 0.7. Observations of neutral hydrogen in the Ly alpha forest in more than 150,000 quasar spectra (g < 22) will constrain BAO over the redshift range 2.15 < z < 3.5. Early results from BOSS include the first detection of the large-scale three-dimensional clustering of the Ly alpha forest and a strong detection from the Data Release 9 data set of the BAO in the clustering of massive galaxies at an effective redshift z = 0.57. We project that BOSS will yield measurements of the angular diameter distance d(A) to an accuracy of 1.0% at redshifts z = 0.3 and z = 0.57 and measurements of H(z) to 1.8% and 1.7% at the same redshifts. Forecasts for Ly alpha forest constraints predict a measurement of an overall dilation factor that scales the highly degenerate D-A(z) and H-1(z) parameters to an accuracy of 1.9% at z similar to 2.5 when the survey is complete. Here, we provide an overview of the selection of spectroscopic targets, planning of observations, and analysis of data and data quality of BOSS

Can editors save peer review from peer reviewers?

<div><p>Peer review is the gold standard for scientific communication, but its ability to guarantee the quality of published research remains difficult to verify. Recent modeling studies suggest that peer review is sensitive to reviewer misbehavior, and it has been claimed that referees who sabotage work they perceive as competition may severely undermine the quality of publications. Here we examine which aspects of suboptimal reviewing practices most strongly impact quality, and test different mitigating strategies that editors may employ to counter them. We find that the biggest hazard to the quality of published literature is not selfish rejection of high-quality manuscripts but indifferent acceptance of low-quality ones. Bypassing or blacklisting bad reviewers and consulting additional reviewers to settle disagreements can reduce but not eliminate the impact. The other editorial strategies we tested do not significantly improve quality, but pairing manuscripts to reviewers unlikely to selfishly reject them and allowing revision of rejected manuscripts minimize rejection of above-average manuscripts. In its current form, peer review offers few incentives for impartial reviewing efforts. Editors can help, but structural changes are more likely to have a stronger impact.</p></div

Effect of referee behavior.

<p><b>A</b>: Average quality of published papers, in percentile of the quality distribution across submitted manuscripts, when impartial and selfish referees are modeled in different ways. impartial referees have either <i>moving standards</i> or <i>fixed standards</i>, and selfish referees are either <i>conscientious</i> or <i>indifferent</i> (see main text for detailed description). Curves show the decline of published quality as the percentage of selfish referees in the pool increases, for each of the four combinations with one type of impartial referee and one type of selfish referee. Thurner and Hanel’s [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0186111#pone.0186111.ref026" target="_blank">26</a>] results correspond to the black curve. <b>B</b>: Percentage of rejected manuscripts by percentage of selfish referees in the pool, for each of the four scenarios. <b>C</b>: Percentage of rejected manuscripts of above-average quality. Error bars represent one standard deviation across ten replicates. Color scheme is consistent across panels.</p

Effect of editor strategies.

<p><b>A</b>: Average quality of accepted papers by percentage of selfish referees in the pool, measured in terms of the percentile of the quality distribution across submitted manuscripts. <i>None</i>: no editorial action; <i>Tiebreak</i>: if the paper is accepted by one referee but rejected by the other, the editor consults a third referee; <i>Bypass refs</i>: papers of exceptionally poor/good quality are automatically rejected/accepted by the editor without review; <i>Blacklist</i>: editor blacklists referees with a higher probability of being selfish than a threshold <i>p</i>. Results are shown for <i>p</i> = 0.5, 0.9. <i>Match refs</i>: editor pairs submitted manuscripts with referees of higher quality to avoid biased rejection from selfish referees; <i>Revision</i>: submitted papers with at least one rejection are sent back for revision and given a second round of reviews; <b>B</b>: Percentage improvement on average quality of published papers relative to no action. <b>C</b>: Percentage of rejected manuscripts by percentage of selfish referees in the pool. <b>D</b>: Percentage of rejected manuscripts with above-average quality. Color scheme in <b>B</b>, <b>C</b> and <b>D</b> identical to <b>A</b>.</p

Evenness in referee load.

<p>Gini coefficient of the distribution of referee load plotted against percentage of selfish referees in the pool. Red and green curves show scenarios when editors blacklist referees with a higher than 50% and 90% chance of being selfish, respectively. Black curve shows Gini coefficient when editors do not blacklist. Referee load is defined as the number of times a scientist served as a referee. The Gini coefficient is half the average absolute difference in referee load across scientists, scaled by the average referee load of all scientists.</p