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The worldwide shortage of single-use N95 respirators and surgical masks due to the COVID-19 pandemic has forced many health care personnel to use their existing equipment for as long as possible. In many cases, workers cover respirators with available masks in an attempt to extend their effectiveness against the virus. Due to low mask supplies, many people instead are using face coverings improvised from common fabrics. Our goal was to determine what fabrics would be most effective in both practices. Under laboratory conditions, we examined the hydrophobicity of fabrics (cotton, polyester, silk), as measured by their resistance to the penetration of small and aerosolized water droplets, an important transmission avenue for the virus causing COVID-19. We also examined the breathability of these fabrics and their ability to maintain hydrophobicity despite undergoing repeated cleaning. Laboratory-based tests were conducted when fabrics were fashioned as an overlaying barrier for respirators and when constructed as face coverings. When used as material in these two situations, silk was more effective at impeding the penetration and absorption of droplets due to its greater hydrophobicity relative to other tested fabrics. We found that silk face coverings repelled droplets in spray tests as well as disposable single-use surgical masks, and silk face coverings have the added advantage over masks such that they can be sterilized for immediate reuse. We show that silk is a hydrophobic barrier to droplets, can be more breathable than other fabrics that trap humidity, and are re-useable via cleaning. We suggest that silk can serve as an effective material for making hydrophobic barriers that protect respirators, and silk can now be tested under clinical conditions to verify its efficacy for this function. Although respirators are still the most appropriate form of protection, silk face coverings possess properties that make them capable of repelling droplets.

What is a voucher and why is it important in research? As a preserved specimen of an identified taxon deposited in a permanent and accessible storage facility, the voucher serves as the supporting material for published studies of the taxon and ensures that the science is repeatable. Vouchers are crucial in authenticating the taxonomy of an organism, as a tool for identifying localities of the taxon, and for additional taxonomic, genetic, ecological, and/or environmental research.

Diversification of (Asparagaceae) in North America has shaped variety in morphological, ecological, and reproductive traits, and resulted in a classification with ambiguity in taxon boundaries, including numerous putative subspecies. Phylogenetic analyses of restriction-site-associated DNA sequences (RADseq) allowed new insights into its evolution and taxonomy, enhancing understanding of basal relationships, geographic patterns, taxonomic boundaries, and potential new species. A total of 157 individuals in 71 populations across all 15 putative taxa of and 42 outgroup individuals in 21 populations from and were sampled and genomic libraries were generated using the modified single-digest RADseq method known as multiplexed shotgun genotyping. Assembly in ipyrad included targeted comparisons across a range of parameters that influence homology assessment and amount of missing data, with analysis of the set of resulting datasets in RAxML and SVDquartets followed by comparison and summary across the sets of trees. Increasing the number of sampled loci improved phylogenetic signal despite concurrent increases in missing data. Each taxon was generally cohesive on the phylogenies, but some species and subspecies were not monophyletic. Results suggest that there was an early separation of and from the rest of the genus during diversification. Different analysis parameters supported either a clade of both species as sister to the remainder of the genus, or alone as sister. Relationships among all relatively deep clades within the genus were well supported. Within species, had particularly robust support for relationships compared to others in , and geographic patterns corresponding to the diversification of some subclades were resolved. The eight subspecies of largely formed two main clades. Although most subspecies showed sufficient phylogenetic, morphological, or ecological distinctiveness to maintain recognition, we recommend synonymizing ssp. into ssp. . Some outlier individuals of were resolved with other species. For example, the status of ssp. was called into question by a well-supported division placing two populations with . In the disjunct species complex distributed further east in North America ( +), results confirmed at least one progenitor-derivative species pair ( arising from ) and some evidence for a potential new taxon closely related to . Overall, these taxa have diversified in traits that can result in genetic isolation, such as differences in flowering seasons and ecological preferences, but there also are indications of some continued gene flow among both subspecies and species.

As tornados become increasingly common with global climate change, recovery of the woody vegetation in temperate forests is imperative to maintain an intact ecosystem. In many urbanized landscapes, invasive species are also increasing and could interfere with natural recovery from environmental disturbance. We quantified the impact and 17‐year recovery from a major tornado in a temperate deciduous forest. We used vegetational surveys in southwestern Ohio at the Harris M. Benedict Nature Preserve, where approximately a third of this site was damaged by a tornado in 1999. Plots were established in the tornado‐damaged area and the nearby undisturbed forest to examine forest recovery of trees/saplings, shrubs and vines, and tree seedlings during 2003, 2006, 2010, and 2016/2017. The number of tree saplings, shrubs, and vines increased immediately after the tornado, but then declined by 2010, relative to the undisturbed forest. Forest tree recruitment was lower in tornado‐damaged sites with fewer tree seedlings, but more saplings. Tree diversity was also affected by Agrilus planipennis (Emerald Ash borer) which targeted native ash trees within this time period. Despite an initial increase in shrubs and vines in the damaged area, the diversity and density of shrubs approached equality in both sites by 2016. Most shrubs in both sites were the invasive Lonicera maackii (Amur honeysuckle). In tornado sites, honeysuckle thinned out over time, leaving larger shrubs with greater mean basal diameter compared to the undisturbed forest. Other woody invasive species were also more prevalent in the damaged area, but increased in number in both locations by 2017. The forest has the capability to begin to recover from the initial tornado, but its future composition may differ from its initial trajectory due to invasive species, loss of ash trees, and anthropogenic impacts within the urban landscape. Invasive Amur honeysuckle (Lonicera maackii) initially increased in the forest damaged by a tornado (black dotted line) compared to the undisturbed forest (solid gray line). Over 17 years, the number of honeysuckle shrubs declined, but those that remained were much larger is size (basal area), especially in damaged areas.

Premise Of the approximately 430 species of oaks (Quercus spp.) that have been assessed, 31% are threatened with extinction and in need of safeguarding. However, oak seeds cannot be seed banked, and thus rely on alternative strategies such as in vitro culture for ex situ conservation. One challenge to this approach is low culture initiation rates. Our objective was to identify factors that may improve the establishment of shoot cultures in vitro using new growth collected from mature trees. Methods Shoot cuttings were harvested from individuals of five different oak species (Q. alba, Q. bicolor, Q. macrocarpa, Q. muehlenbergii, and Q. palustris). Shoots were cultured onto medium with or without 50 µM silver thiosulfate (STS), a known inhibitor of the stress hormone ethylene. Cultures were grown for one month, at which point shoots were assessed for survival. Results Shoot survival was significantly greater in shoots cultured on medium containing STS compared to the control group, with the overall survival rate increasing from 65% to 73%. Discussion Increasing the survival rate of newly established cultures is important in ensuring that material collected from endangered species has the best chance for survival, which is critical for successful ex situ conservation.

Hybridization between genetically distinct populations of a single species can serve as an important stimulus for the evolution of invasiveness. Such intraspecific hybridization was examined in Pyrus calleryana, a Chinese tree species commonly planted as an ornamental in residential and commercial areas throughout the United States. This self-incompatible species is now escaping cultivation and appearing in disturbed habitats, where it has the potential to form dense thickets. Using genetic techniques incorporating nine microsatellite markers, we show that abundant fruit set on cultivated trees as well as the subsequent appearance of wild individuals result from crossing between genetically distinct horticultural cultivars of the same species that originated from different areas of China. We conclude that intraspecific hybridization can be a potent but little recognized process impacting the evolution of invasiveness in certain species.

In spite of the remarkable progress made in the development of safe and effective vaccines against COVID-19, deployment of respiratory protective devices remains vital for mitigating the transmission of SARS-CoV-2 during the ongoing pandemic. In this study, we evaluated double masking, which entails layering a fitted over-mask on top of a surgical mask. A previously validated manikin-based protocol was used to evaluate the performance of a surgical mask with an over-mask made of silk or cotton. We showed that double masking can significantly enhance the mask’s source control capabilities by reducing an aerosol emission from a coughing or sneezing wearer while maintaining a reasonable breathability and comfort level. The data obtained in this study, as well as the results recently reported by other investigators, suggest that an over-mask made of silk fabric has several advantages over one made of cotton. Moreover, silk over-masks have the added benefit of providing a reusable protective outer layer for surgical masks as silk is hydrophobic and increases aerosol particle collection. Not only can double masking reduce viral or bacterial transmission, but it can also promote surgical mask longevity, thereby reducing global waste and pollution associated with the use of disposable surgical masks. Finally, an additional study with five human subjects revealed no significant differences in perceived comfort (measured by proxies such as relative humidity, temperature, and CO 2 level inside the mask) between single masking and double masking, as well as between double masking with either a silk or cotton over-mask.

Plant coloration, shown to play a dynamic role in animal attraction, has been proposed as a means of defense, although these reports lack experimental evidence. This study empirically assesses defensive coloration in the mycoheterotrophic plant, Monotropsis odorata, which produces stems and flowers covered by dried vegetative bracts. Field studies were conducted using an experimental group of plants with bracts removed and a control group to evaluate the frequency of and fitness impacts associated with herbivory. Additionally, we quantitatively assessed the reflectance spectra of bracts, stems, and flowers of M. odorata relative to an ambient leaf litter substrate. Across the 2-yr study, the experimental group experienced a 20-27% higher mean herbivory rate and 7-20% lower mean fruit production relative to the control group. Bracts were shown to strongly resemble ambient leaf litter in spectral analyses, with stems and flowers having more conspicuous coloration. Results show that the presence of dried bracts effectively camouflages conspicuous stem and floral tissues, significantly reducing the frequency of floral and stem herbivory, and thereby increasing fruit set, a component of plant fitness. This study supports the principal hypothesis that coloration can play a fundamental role in plant defense.