Nondisclosure of queer identities is associated with reduced scholarly publication rates.

Nondisclosure of lesbian, gay, bisexual, transgender, asexual, or otherwise queer (LGBTQA) identities in the workplace is both common and stressful to those who do not disclose. However, we lack direct evidence that nondisclosure of LGBTQA identity affects worker productivity. In two surveys of LGBTQA-identified scientists, we found that those who did not disclose LGBTQA identities in professional settings authored fewer peer-reviewed publications-a concrete productivity cost. In the second survey, which included straight and cisgender participants as a comparison group, we found that LGBTQA participants who disclosed their sexual orientation had publication counts more like non-LGBTQA participants than those who did not disclose, and that all three groups had similar time since first publication given their academic career stage. These results are most consistent with a productivity cost to nondisclosure of LGBTQA identity in professional settings, and suggest a concrete need to improve scientific workplace climates for sexual and gender minorities.

XANES reflects coordination change and underlying surface disorder of zinc adsorbed to silica.

Zinc K-edge X-ray absorption near-edge structure (XANES) spectroscopy of Zn adsorbed to silica and Zn-bearing minerals, salts and solutions was conducted to explore how XANES spectra reflect coordination environment and disorder in the surface to which a metal ion is sorbed. Specifically, XANES spectra for five distinct Zn adsorption complexes (Znads) on quartz and amorphous silica [SiO2(am)] are presented from the Zn-water-silica surface system: outer-sphere octahedral Znads on quartz, inner-sphere octahedral Znads on quartz, inner-sphere tetrahedral Znads on quartz, inner-sphere octahedral Znads on SiO2(am) and inner-sphere tetrahedral Znads on SiO2(am). XANES spectral analysis of these complexes on quartz versus SiO2(am) reveals that normalized peak absorbance and K-edge energy position generally decrease with increasing surface disorder and decreasing Zn-O coordination. On quartz, the absorption-edge energy of Znads ranges from 9663.0 to 9664.1 eV for samples dominated by tetrahedrally versus octahedrally coordinated species, respectively. On SiO2(am), the absorption-edge energy of Znads ranges from 9662.3 to 9663.4 eV for samples dominated by tetrahedrally versus octahedrally coordinated species, respectively. On both silica substrates, octahedral Znads presents a single K-edge peak feature, whereas tetrahedral Znads presents two absorbance features. The energy space between the two absorbance peak features of the XANES K-edge of tetrahedral Znads is 2.4 eV for Zn on quartz and 3.2 eV for Zn on SiO2(am). Linear combination fitting of samples with a mixture of Znads complex types demonstrates that the XANES spectra of octahedral and tetrahedral Znads on silica are distinct enough for quantitative identification. These results suggest caution when deciphering Zn speciation in natural samples via linear combination approaches using a single Znads standard to represent sorption on a particular mineral surface. Correlation between XANES spectral features and prior extended X-ray absorption fine structure (EXAFS) derived coordination environments for these Znads on silica samples provides insight into Zn speciation in natural systems with XANES compatible Zn concentrations too low for EXAFS analysis.

Cr(VI) reduction by Fe(II) sorbed to silica surfaces.

The reaction kinetics of groundwater contaminants are integral to evaluating the fate and transport of toxic metals in the environment. For redox sensitive contaminants, such as chromium, the kinetics of different reaction pathways can vary by orders of magnitude. Species-specific rate constants for iron-chromium oxidation-reduction reactions are unknown for many systems, especially in the presence of sorbing surfaces. We investigate the role of quartz and amorphous silica (SiO2(am)) surfaces in mediating abiotic reduction of Cr(VI)aq by aqueous and sorbed Fe(II) using batch sorption and redox experiments. Sorption edges indicate outer-sphere (Fe(II)ads,OS) and inner-sphere (Fe(II)ads,IS) complexes are present on both silica surfaces, and their abundance depends on pH, ionic strength, and surface disorder. The rate constants for Cr(VI)aq reduction by Fe(II) species increase in the following order: kaq ≪ kads,OS,quartz < kads,OS,SiO2(am) < kads,IS,quartz < kads,IS,SiO2(am), suggesting that increasing proximity of Fe(II) to the negatively charged silica surface enhances the rate of reduction of Cr(VI)aq. However, we observe that experiments with larger amounts of sorbed Fe(II) reduce less total Cr(VI)aq over time, which we attribute to a portion of the sorbed Fe(II) being sequestered into the Cr(III)-Fe(III)-oxyhydroxide precipitates forming on the silica surface. Therefore, the balance between increases in the rate and decreases in the total amount of Cr(VI)aq reduction by various sorbed Fe(II) species must be considered when devising remediation strategies.

A Phylogenomic Solution to the Origin of Insects by Resolving Crustacean-Hexapod Relationships.

Insects, the most diverse group of organisms, are nested within crustaceans, arguably the most abundant group of marine animals. However, to date, no consensus has been reached as to which crustacean taxon is the closest relative of hexapods. A majority of studies have proposed that Branchiopoda (e.g., fairy shrimps) is the sister group of Hexapoda [1-7]. However, these investigations largely excluded two equally important taxa, Remipedia and Cephalocarida. Other studies suggested Remipedia [8-11] or Remipedia + Cephalocarida [12, 13] as potential sister groups of hexapods, but they either did not include Cephalocarida or used only Sanger sequence data and morphology [9, 12]. Here we present the first phylogenomic study specifically addressing the origins of hexapods, including transcriptomes for two species each of Cephalocarida and Remipedia. Phylogenetic analyses of selected matrices, ranging from 81 to 1,675 orthogroups and up to 510,982 amino acid positions, clearly reject a sister-group relationship between Hexapoda and Branchiopoda [1-7]. Nonetheless, support for a hexapod sister-group relationship to Remipedia or to Cephalocarida-Remipedia was highly dependent on the employed analytical methodology. Further analyses assessing the effects of gene evolutionary rate and targeted taxon exclusion support Remipedia as the sole sister taxon of Hexapoda and suggest that the prior grouping of Remipedia + Cephalocarida is an artifact, possibly due to long branch attraction and compositional heterogeneity. We further conclude that terrestrialization of Hexapoda probably occurred in the late Cambrian to early Ordovician, an estimate that is independent of their proposed sister group [4, 8, 12, 14].

High-throughput method for simultaneous quantification of N, C and S stable isotopes and contents in organics and soils.

RATIONALE: Information about the sulfur stable isotope composition (δ(34) S value) of organic materials and sediments, in addition to their nitrogen (δ(15) N value) and carbon (δ(13) C value) stable isotope compositions, can provide insights into mechanisms and processes in different areas of biological and geological research. The quantification of δ(34) S values has traditionally required an additional and often more difficult analytical procedure than NC dual analysis. Here, we report on the development of a high-throughput method that simultaneously measures the elemental and isotopic compositions of N, C and S in a single sample, and over a wide range of sample sizes and C/N and C/S ratios. METHODS: We tested a commercially available CHNOS elemental analyzer in line with an isotope ratio mass spectrometer for the simultaneous quantification of N, C and S stable isotope ratios and contents, and modified the elemental analyzer in order to overcome the interference of (18) O in δ(34) S values, to minimize any water condensation that could also influence S memory, and to achieve the complete reduction of nitrogen oxides to N2 gas for accurate measurement of δ(15) N values. A selection of organic materials and soils was analyzed with a ratio of 1:1.4 standards to unknowns per run. RESULTS: The modifications allowed high quality measurements for N, C and S isotope ratios simultaneously (1 SD of ±0.13‰ for δ(15) N value, ±0.12‰ for δ(13) C value, and ±0.4‰ for δ(34) S value), with high throughput (>75 unknowns per run) and over a wide range of element amount per capsule (25 to 500 µg N, 200-4000 µg C, and 8-120 µg S). CONCLUSIONS: This method is suitable for widespread use and can significantly enhance the application of δ(34) S measurements in a broad range of soils and organic samples in ecological and biogeochemical research. Copyright © 2016 John Wiley & Sons, Ltd.

Uranium incorporation into amorphous silica.

High concentrations of uranium are commonly observed in naturally occurring amorphous silica (including opal) deposits, suggesting that incorporation of U into amorphous silica may represent a natural attenuation mechanism and promising strategy for U remediation. However, the stability of uranium in opaline silicates, determined in part by the binding mechanism for U, is an important factor in its long-term fate. U may bind directly to the opaline silicate matrix, or to materials such as iron (hydr)oxides that are subsequently occluded within the opal. Here, we examine the coordination environment of U within opaline silica to elucidate incorporation mechanisms. Precipitates (with and without ferrihydrite inclusions) were synthesized from U-bearing sodium metasilicate solutions, buffered at pH ∼ 5.6. Natural and synthetic solids were analyzed with X-ray absorption spectroscopy and a suite of other techniques. In synthetic amorphous silica, U was coordinated by silicate in a double corner-sharing coordination geometry (Si at ∼ 3.8-3.9 Å) and a small amount of uranyl and silicate in a bidentate, mononuclear (edge-sharing) coordination (Si at ∼ 3.1-3.2 Å, U at ∼ 3.8-3.9 Å). In iron-bearing synthetic solids, U was adsorbed to iron (hydr)oxide, but the coordination environment also contained silicate in both edge-sharing and corner-sharing coordination. Uranium local coordination in synthetic solids is similar to that of natural U-bearing opals that retain U for millions of years. The stability and extent of U incorporation into opaline and amorphous silica represents a long-term repository for U that may provide an alternative strategy for remediation of U contamination.

Effects of antennule morphology and flicking kinematics on flow and odor sampling by the freshwater crayfish, Procambarus clarkii.

The flow structure around the lateral antennular flagellum of the freshwater crayfish, Procambarus clarkii, was quantified to determine how antennule morphology and flicking kinematics affect fine-scale flow surrounding their chemosensory sensilla, called aesthetascs. Particle image velocimetry was used to measure velocity and vorticity of flow between aesthetascs of dynamically scaled physical models of P. clarkii antennules. Results revealed that the spacing between aesthetascs and antennule flicking speed induces substantial changes in fluid flow near aesthetascs. The downstroke flicking motion of the antennule occurs at a peak speed of 2.7cm/s. The returnstroke occurs at approximately 70% of this speed, but the fluid velocity between aesthetascs during the returnstroke is approximately 15% compared with the downstroke. The significant decrease in fluid flow near aesthetascs results from the reduced antennule speed and from the coupled interaction of boundary layers of the aesthetascs and antennule during the returnstroke. Odorant-laden fluid captured during the downstroke is retained between the aesthetascs during the slower returnstroke, and sufficient time occurs for odorant molecules to molecularly diffuse to aesthetasc surfaces. In addition, locally generated vorticity was observed near the tip of the aesthetascs, which may induce odorant transport to aesthetasc surfaces and enhance olfactory response times to odors.