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Herein, we describe the design and synthesis of 16 neo‐glycolipids that are potential permeation enhancers for oral drug delivery of peptide therapeutics. These amphiphilic neo‐glycolipids are composed of fatty acids and various carbohydrates (d‐glucose, lactose, cellobiose, maltose) via an oxime linker. The ability of the synthesized neo‐glycolipids to enhance permeation of fluorescein‐labelled dextran (4 kDa) or 3H‐mannitol across intestinal epithelium was investigated in vitro using monolayers of human epithelial Caco‐2 cells. Their effects were compared with (pre‐)clinically known enhancers as reference compounds; sodium salts of octanoic, decanoic, and dodecanoic acid, and sodium salcaprozate (SNAC). Most neo‐glycolipids increased the permeation of the model compounds, proving that neo‐glycolipids, which possess vastly different properties from the reference compounds, e. g. in terms of clogD and polar surface area, are effective permeation enhancers. The neo‐glycolipid based on decanoic acid and glucose was more potent than related compounds based on disaccharides. Significant differences in solubility and cellular compatibility were found for neo‐glyolipids based on different carbohydrates. Finally, neo‐glycolipids were evaluated as permeation enhancers for the peptide hormone PYY3‐36. Glucose‐ and maltose‐derived neo‐glycolipids based on decanoic and dodecanoic acid showed promising enhancements in PYY3‐36 permeation in vitro while maintaining good cellular compatibility, relevant for oral delivery of obesity treatments. [ABSTRACT FROM AUTHOR]

Supplemental feeding of wild ungulates has long been and remains a common practice across Europe and North America. Yet by drawing animals together, supplemental feeding can have unintended, negative effects on individual species and broader ecological processes. These include increased risk of disease transmission, intraspecific and interspecific competition, and predation, which are of management concern for white‐tailed deer (Odocoileus virginianus) in the southeastern United States given the arrival of nonnative wild pigs (Sus scrofa) and coyotes (Canis latrans). We conducted a field experiment between March and July of 2021 to assess the effects of supplemental feeding on spatiotemporal activity patterns of deer and wild pigs at wildlife feeders, and space use of coyotes in the Piedmont region of South Carolina, USA. We observed support for our hypothesis that interspecific competition through increased visitation by larger groups of competitor species reduces use of foraging sites by other subordinate ungulates, where feeders highly visited by wild pigs were rarely visited by deer. While adult deer and wild pigs generally did not shift their temporal activity patterns at feeders, juvenile temporal activity shifted to more frequent visits of feeders during the night, supporting our hypothesis that supplemental feed could increase risk to predator exposure, as coyotes tend to be active during crepuscular hours. Our findings suggest that supplemental feed put out to encourage deer activity could actually deter deer if wild pigs occupy that area, and has potential negative demographic effects if juveniles are at increased risk of predation. Collectively, based on our data, we do not recommend supplemental feeding in the southeastern United States where white‐tailed deer, coyotes, and wild pigs co‐occur. More broadly, given how widespread the legal use of supplemental feed remains across the United States, we encourage landowners and policymakers to consider the full suite of potential direct and indirect, short‐term and long‐term negative impacts supplemental feeding can have on both target and nontarget wildlife populations. [ABSTRACT FROM AUTHOR]

The increasing energy demand in information technologies requires novel low‐power procedures to store and process data. Magnetic materials, central to these technologies, are usually controlled through magnetic fields or spin‐polarized currents that are prone to the Joule heating effect. Magneto‐ionics is a unique energy‐efficient strategy to control magnetism that can induce large non‐volatile modulation of magnetization, coercivity and other properties through voltage‐driven ionic motion. Recent studies have shown promising magneto‐ionic effects using nitrogen ions. However, either liquid electrolytes or prior annealing procedures are necessary to induce the desired N‐ion motion. In this work, magneto‐ionic effects are voltage‐triggered at room temperature in solid state systems of CoxMn1‐xN films, without the need of thermal annealing. Upon gating, a rearrangement of nitrogen ions in the layers is observed, leading to changes in the co‐existing ferromagnetic and antiferromagnetic phases, which result in substantial increase of magnetization at room temperature and modulation of the exchange bias effect at low temperatures. A detailed correlation between the structural and magnetic evolution of the system upon voltage actuation is provided. The obtained results offer promising new avenues for the utilization of nitride compounds in energy‐efficient spintronic and other memory devices. [ABSTRACT FROM AUTHOR]

Aim: Synthesize literature on genetic structure within species to understand how geographic features and species traits influence past responses to climate change. Location: North America. Time Period: We synthesized phylogeographic studies from 1978 to 2023, which describe genetic lineages that diverged during the Pleistocene (≥11,700 years ago). Major Taxa Studied: Mammals. Methods: We conducted a literature review to map genetic breaks in species distributions, then tested a set of geographic hypotheses (e.g., mountains, rivers) to explain their position by comparing break locations to a grid within each species' sampled range using logistic regression. We then conducted a meta‐analysis using species‐specific model estimates to ask if life‐history traits explained variation in which barriers were most important in species' past response to climate change. Results: Our findings reveal heterogeneity in both where North American mammal phylogeography has been studied and the density of genetic breaks across 229 species. We found relatively high concordance among carnivores, ungulates and lagomorphs, where breaks were associated with mountains, major water bodies and relatively even terrain. In contrast, we found high variability within rodents and shrews, and no evidence that intrinsic factors related to dispersal ability explained the importance of hypothesized barriers across all species. Main Conclusions: Southern Mexico is a hotspot for genetic breaks that has yet to be integrated into the broader story of North American phylogeography. We show that mountains and major water bodies play particularly important roles as barriers, but substantial variation across species within orders suggests that there is more to the story besides shared climatic or phylogenetic histories. Thus, understanding the phylogeography of individual species will continue to be important given that our results suggest high variability in how species may respond to future global change. [ABSTRACT FROM AUTHOR]

Predators impose top‐down forces on prey populations, with the strength of those effects often varying over space and time and among demographic groups. In ungulates, predation risk is typically greatest for neonatal offspring, with some suggesting that predators can key in on adult activity to locate hidden neonates. However, few field studies to date have been able to directly assess the influence of maternal care on ungulate neonate survival. Using a population of white‐tailed deer under heavy coyote predation pressure, we tested the maternal dispersion hypothesis, which suggests the dispersion of maternal activity temporally and spatially attenuates risk of predation for ungulate neonates during this vulnerable altricial phase. We compared support for this hypothesis with more commonly tested hypotheses regarding the influence of habitat conditions and intrinsic factors on neonatal survival. Fawn survival to 16 weeks was 27.7%, with coyotes accounting for 59% of fawn mortalities. In support of our maternal temporal diffusion hypothesis, we found that neonatal survival decreased as more maternal visits (proportionally) occurred at night. The only other significant (p <.1) predictor of fawn survival was birth timing, with fawn survival decreasing as the season progressed. Given that fawn survival declined as the proportion of nighttime visits increased, and that wild pig presence and human disturbance can push doe and fawn activity toward nocturnal hours, additional research is needed to determine whether managing pig and human disturbance can decrease fawn mortality. More broadly, given the importance of recruitment in ungulate population dynamics, our finding opens a potentially important new line of inquiry on how maternal behaviors influence predation risk in large animal predator–prey ecology. [ABSTRACT FROM AUTHOR]

Resource pulses are ecologically important phenomenon that occur in most ecosystems globally. Following optimal foraging theory, many consumers switch to pulsatile foods when available, examples of which include fruit mast and vulnerable young prey. Yet how the availability of resource pulses shapes the ecology of predators is still an emerging area of research; and how much individual variation there is in response to pulses is not well understood. We hypothesized that resource pulses would lead to dietary convergence in our population, which we tested by tracking both population‐level and individual coyote diets for 3 years in South Carolina, USA. We (1) described seasonal dietary shifts in relation to resource pulses; (2) compared male and female diets across seasons; and (3) tested this dietary convergence hypothesis by quantifying individual dietary variation both across and within periods when resource pulses were available. We found that pulses of white‐tailed deer fawns and blackberries composed over half of coyote diet in summer, and persimmon fruits were an important component in fall. Male and female coyotes generally had similar diets, but males consumed more deer in fall, perhaps driven by scavenging more. We found support for our dietary convergence hypothesis, where individuals had more similar diets during resource pulses compared to a non‐pulse period. We also found that this convergence happened before peak availability, suggesting a non‐symmetric response to pulse availability. We show that nearly all coyotes eat fawns, suggesting that targeted efforts to remove "fawn killers" would be in vain. Instead, given how quickly coyotes collectively converge on resource pulses, our findings show that resource pulses could potentially be used by managers to alter the behavior of apex predators. More broadly, we open a new line of inquiry into how variation in individual foraging decisions scales up to shape the effects of resource pulses on ecological communities. [ABSTRACT FROM AUTHOR]

Site occupancy models (SOMs) are a common tool for studying the spatial ecology of wildlife. When observational data are collected using passive monitoring field methods, including camera traps or autonomous recorders, detections of animals may be temporally autocorrelated, leading to biased estimates and incorrectly quantified uncertainty. We presently lack clear guidance for understanding and mitigating the consequences of temporal autocorrelation when estimating occupancy models with camera trap data.We use simulations to explore when and how autocorrelation gives rise to biased or overconfident estimates of occupancy. We explore the impact of sampling design and biological conditions on model performance in the presence of autocorrelation, investigate the usefulness of several techniques for identifying and mitigating bias and compare performance of the SOM to a model that explicitly estimates autocorrelation. We also conduct a case study using detections of 22 North American mammals.We show that a join count goodness‐of‐fit test previously proposed for identifying clustered detections is effective for detecting autocorrelation across a range of conditions. We find that strong bias occurs in the estimated occupancy intercept when survey durations are short and detection rates are low. We provide a reference table for assessing the degree of bias to be expected under all conditions. We further find that discretizing data with larger windows decreases the magnitude of bias introduced by autocorrelation. In our case study, we find that detections of most species are autocorrelated and demonstrate how larger detection windows might mitigate the resulting bias.Our findings suggest that autocorrelation is likely widespread in camera trap data and that many previous studies of occupancy based on camera trap data may have systematically underestimated occupancy probabilities. Moving forward, we recommend that ecologists estimating occupancy from camera trap data use the join count goodness‐of‐fit test to determine whether autocorrelation is present in their data. If it is, SOMs should use large detection windows to mitigate bias and more accurately quantify uncertainty in occupancy model parameters. Ecologists should not use gaps between detection periods, which are ineffective at mitigating temporal structure in data and discard useful data. [ABSTRACT FROM AUTHOR]

Anvil cirrus generated by deep convection covers large fractions of the tropics and has important impacts on the Earth's radiation budget and climate. In situ measurements made with high‐altitude aircraft indicate a rapid transition in ice crystal size distributions and habits as anvil cirrus ages. We use numerical simulations to investigate the impact of high‐frequency gravity waves on the evolution of anvil cirrus microphysical properties. The impacts of both monochromatic gravity waves and ubiquitous stochastic mesoscale temperature fluctuations are simulated. In both cases, the interplay between wave‐driven temperature fluctuations, deposition growth/sublimation, and sedimentation causes accelerated removal of both small ice crystals (diameters less than about 10 μm) and large crystals (diameters larger than ≈30 μm). These changes are consistent with the observed evolution of anvil cirrus microphysical properties. The Kelvin effect (higher saturation vapor pressure over curved surfaces) is a critical factor in the anvil evolution, driving mass transfer from small to large ice crystals. The wave‐driven decrease in ice concentration is much faster for typical anvil cirrus detrained at ≃11.5–12.5 km than for less frequent anvils at 15.5–17.5 km because of the strong temperature dependence of deposition growth and sublimation rates. The simulations also show that waves, along with the Kelvin effect, drive growth of mid‐sized (5–20 μm) ice crystals, which is consistent with the observed transition to bullet rosette habits in aging anvil cirrus. We conclude that high‐frequency gravity waves, which are generally not resolved in large‐scale models, likely have important impacts on anvil cirrus microphysical properties and lifetimes. Key Points: Gravity wave temperature fluctuations, along with the Kelvin effect, rapidly reduce small ice crystal concentrations in anvil cirrusWaves and the Kelvin effect drive mass transfer from small to large crystals, consistent with the prevalence of bullet rosettes in anvilsWave effects on anvil cirrus microphysics are much more pronounced for low/warm anvils than for high/cold anvils [ABSTRACT FROM AUTHOR]

Aircraft measurements reveal ice supersaturation statistics in cirrus (ISSs) with broad maxima around ice saturation and pronounced variance. In this study, processes shaping ISSs in midlatitude and tropical upper tropospheric conditions are systematically investigated. Water vapor deposition and sublimation of size‐resolved ice crystal populations are simulated in an air parcel framework. Mesoscale temperature fluctuations (MTFs) due to gravity waves force the temporal evolution of supersaturation. Various levels of background wave forcing and cirrus thickness are distinguished in stochastic ensemble simulations. Kinetic limitations to ice mass growth are brought about by supersaturation‐dependent deposition coefficients that represent efficient and inefficient growth modes as a function of ice crystal size. The simulations identify a wide range of deposition coefficients in cirrus, but most values stay above 0.01 such that kinetic limitations to water uptake remain moderate. Supersaturation quenching times are long, typically 0.5–2 hr. The wave forcing thus causes a remarkably large variability in ISSs and cirrus microphysical properties except in the thickest cirrus, producing ensemble‐mean ISSs in line with in‐situ measurements. ISS variance is controlled by MTFs and increases with decreasing cirrus integral radii. In comparison, the impact of ice crystal growth rates on ISSs is small. These results contribute to efforts directed at identifying and solving issues associated with ice‐supersaturated areas and non‐equilibrium cirrus physics in global models. Plain Language Summary: Measurements show that cold, high cirrus clouds evolve in ice‐supersaturated states away from equilibrium, which sets them apart from low‐level liquid water clouds. Such cloud states are brought about by rapidly displacing cloudy air parcels in the vertical wind field. The resulting temperature changes cause ice crystals to either grow or shrink in size by uptake or release of water molecules, which, in turn, tends to restore equilibrium. We carefully examine how ice supersaturation and cirrus properties respond to changes in vertical wind speeds for various ice growth models. We show that cloud‐scale wave motions determine to a large extent the frequency of occurrence of ice‐supersaturated states. The sensitivity to cloud ice growth is much weaker. Our results help interpret atmospheric observations and may improve the representation of cirrus in global models. Key Points: This study presents a process‐based, systematic investigation of key factors controlling ice supersaturation statistics within cirrusGravity wave‐induced mesoscale temperature fluctuations cause a remarkably large variability in ice supersaturationIce supersaturation statistics are not strongly modified by depositional growth with supersaturation‐dependent deposition coefficients [ABSTRACT FROM AUTHOR]

Vegetation is a key component controlling soil accretion in coastal wetlands through production of belowground organic matter and enhanced deposition of mineral sediments. Vegetation structure is a proxy for wetland health and degradation that can be monitored at large scales with remote sensing. Among different multispectral indices, the Normalized Difference Vegetation Index (NDVI) is generally used for this purpose. Using Google Earth Engine (GEE), NDVI time‐series are extracted around 45 monitoring stations of the Coastwide Reference Monitoring System (CRMS) located in Terrebonne Bay, Louisiana, USA. NDVI tends to increase from saline to freshwater wetlands. Using these NDVI observations and in situ measurements of salinity, soil accretion rates, and geomorphic metrics (i.e., elevation, distance from the bay or from the nearest channel bank), empirical models were developed to derive maps of organic mass accumulation rates and salinity. The analysis shows that NDVI can be used to reproduce the salinity gradient in Terrebonne Bay, as the index captures differences in vegetation cover, which depend on salinity. A negative relationship between NDVI and organic accumulation mass rates is also found, indicating that saline marshes tend to accumulate more organic material compared to fresh wetlands. Plain Language Summary: Coastal wetlands need to increase their elevation to counterbalance relative sea level rise. This process is achieved through deposition of mineral sediment and organic matter produced by local vegetation. The latter contribution becomes fundamental in areas lacking mineral supply. In this study, we show that it is possible to leverage on the Normalized Difference Vegetation Index (NDVI), a very common remote sensing indicator, to derive the contribution of vegetation to soil accumulation. Moreover, the same index can be used to derive the distribution of salinity. These results can be achieved because NDVI is related to the general plant type, which changes when we move from saline to freshwater wetlands. Key Points: Average NDVI values are used to derive distribution of salinity and organic mass accumulation rates in Terrebonne Bay, LouisianaNDVI reflects different plant types in the wetlands of Terrebonne BayOn average 0.065 g cm−2 yr−1 of organic mass are accumulated on a yearly basis in Terrebonne Bay [ABSTRACT FROM AUTHOR]

Large carcasses often attract multiple carnivore species, so subordinate carnivores must weigh the reward of a profitable meal with the risk of being attacked by dominant carnivores. These risk–reward trade‐offs are likely influenced by a variety of factors, including scale‐dependent risk from dominant carnivores (e.g., short‐ vs. long‐term risk) and the amount of carcass remaining. In the southeastern United States, human hunters provision a large amount of white‐tailed deer carrion, which appears to be an important food source for coyotes (a novel top predator), but we know little about how coyotes influence the scavenging behavior of smaller carnivores. In this study, we evaluated the relative importance of risk from coyotes, vulture activity, forest structure, and remaining food on bobcat, gray fox, raccoon, and opossum scavenging by deploying 71 deer carcasses within a managed forest in South Carolina during January 2020 and 2021. We found that coyotes only had direct effects on bobcat behavior, suggesting that competition for carcasses was greatest between these two species. However, the relative importance of long‐ versus short‐term risk from coyotes was dependent on the stage in the scavenging process. Effects from forest structure were also stage‐dependent, where tree density and age were related to carcass discovery for bobcats and raccoons, while minimal understory cover facilitated bobcat, gray fox, and opossum scavenging, despite short‐term risk from coyotes. Vulture activity appeared to serve as a cue for gray foxes to discover carcasses. Ultimately, we found that risk from coyotes had species‐specific and context‐dependent effects on smaller carnivore scavenging. This represents some of the first direct evidence of how coyotes alter smaller carnivore behavior in a region where coyotes are a novel top predator. However, forest structure (particularly understory cover) seemed to mediate risk from coyotes, highlighting how habitat can influence predator–predator interactions. Future research should also investigate these interactions during other times of the year and try to quantify how human‐provisioned carcasses influence populations and communities. [ABSTRACT FROM AUTHOR]

Wild pigs (Sus scrofa), which are invasive in many regions globally, can alter ecosystems and compete with native species through interference competition and resource exploitation. Wild pig impacts on other species may increase with greater niche overlap, which could vary over time based on environmental conditions, resource availability, or biological traits like diet, especially as seasonal variation in wild pig diet has been widely documented. A limited number of studies have assessed spatial or temporal overlap between native species and invasive wild pigs, with only a handful simultaneously assessing overlap in these niche dimensions. We investigated the potential for interspecific interactions involving invasive wild pigs in the Piedmont region of South Carolina, USA, by examining seasonal spatiotemporal overlap with other wildlife using N‐mixture models and diel activity overlap analyses. Site use by white‐tailed deer (Odocoileus virginianus) and coyote (Canis latrans) was negatively associated with wild pig activity in the fall, when the species had high diel activity overlap, indicating spatial partitioning could reduce interference competition with wild pigs in this season. Conversely, white‐tailed deer site use was positively associated with wild pig activity in the winter, suggesting higher spatial overlap may be necessary if resources are limited. Site use by bobcat (Lynx rufus) and nine‐banded armadillo (Dasypus novemcinctus) in the spring, along with raccoon (Procyon lotor) and wild turkey (Meleagris gallopavo) site use in the summer, was positively associated with wild pig activity. With the exception of diurnal wild turkey, diel activity overlap between these species and wild pigs was high, although temporal partitioning could have occurred at finer spatiotemporal scales than we examined. Our results collectively emphasize the importance of accounting for seasonal spatial and temporal responses by individual species to invasive wild pigs, with special consideration given to species in seasons where high niche overlap with wild pigs is anticipated. [ABSTRACT FROM AUTHOR]

Amplicon‐sequence data from environmental DNA (eDNA) and microbiome studies provide important information for ecology, conservation, management, and health. At present, amplicon‐sequencing studies—known also as metabarcoding studies, in which the primary data consist of targeted, amplified fragments of DNA sequenced from many taxa in a mixture—struggle to link genetic observations to the underlying biology in a quantitative way, but many applications require quantitative information about the taxa or systems under scrutiny. As metabarcoding studies proliferate in ecology, it becomes more important to develop ways to make them quantitative to ensure that their conclusions are adequately supported. Here we link previously disparate sets of techniques for making such data quantitative, showing that the underlying polymerase chain reaction mechanism explains the observed patterns of amplicon data in a general way. By modeling the process through which amplicon‐sequence data arise, rather than transforming the data post hoc, we show how to estimate the starting DNA proportions from a mixture of many taxa. We illustrate how to calibrate the model using mock communities and apply the approach to simulated data and a series of empirical examples. Our approach opens the door to improve the use of metabarcoding data in a wide range of applications in ecology, public health, and related fields. [ABSTRACT FROM AUTHOR]

Many ecological data sets are proportional, representing mixtures of constituent elements such as species, populations, or strains. Analyses of proportional data are challenged by categories with zero observations (zeros), all observations (ones), and overdispersion. In lieu of ad hoc data adjustments, we describe and evaluate a zero‐and‐one inflated Dirichlet regression model, with its corresponding R package (zoid), capable of handling observed data x$$ x $$ consisting of three possible categories: zeros, proportions, or ones. Instead of fitting the model to observations of single biological units (e.g., individual organisms) within a sample, we sum proportional contributions across units and estimate mixture proportions using one aggregated observation per sample. Optional estimation of overdispersion and covariate influences expand model applications. We evaluate model performance, as implemented in Stan, using simulations and two ecological case studies. We show that zoid successfully estimates mixture proportions using simulated data with varying sample sizes and is robust to overdispersion and covariate structure. In empirical case studies, we estimate the composition of a mixed‐stock Chinook salmon (Oncorhynchus tshawytscha) fishery and analyze the stomach contents of Atlantic cod (Gadus morhua). Our implementation of the model as an R package facilitates its application to varied ecological data sets composed of proportional observations. [ABSTRACT FROM AUTHOR]

We describe and validate a method of calculating convective cloud top altitudes and potential temperatures up to 50° latitude at high spatial (0.25°) and temporal (3 hr) resolution. The approach uses the statistics of the CloudSat cloud radar deep convective cloud classification product coupled with nighttime CALIOP lidar measurements to effectively "calibrate" the high frequency, high resolution global rainfall and brightness temperature data that is used to derive convective cloud top altitudes. Thus, our product agrees well with the statistics of the CloudSat/CALIOP convective cloud tops, especially in the tropics and over oceanic regions. Agreement is reasonable, but not as good, for land‐based convection. The estimated uncertainty in cloud top altitudes in our product is 0.5–1.0 km over land areas, with smaller uncertainties over the oceans. The diurnal cycle of the new convection data set is in good agreement with precipitation radar convective climatology. Plain Language Summary: Convection modifies the water vapor concentration and injects trace gases into the upper troposphere and the lower stratosphere. To quantify the impact of convection, we have developed a data set of convective cloud top altitudes. Our algorithm uses lidar and cloud radar data to calibrate a combination of rainfall and geostationary satellite brightness temperature data to produce a database of convective cloud top altitudes. The statistics of our high‐resolution convective cloud top altitudes agree well with the statistics of other more limited convective cloud top data sets, especially over the oceans and in the tropics. Key Points: A high resolution data set of convective cloud top altitudes is calculated based on rainfall and brightness temperature observationsThe frequency statistics and diurnal cycle of this data set show good agreement with other observationsThe uncertainty in the data set of convective cloud tops is 0.5–1.0 km, or 5–15 K potential temperature [ABSTRACT FROM AUTHOR]

Coyotes Canis latrans have expanded their geographic range by 40% in the last 120 years, raising questions about their ecological impacts in the newly colonised areas. Despite a wealth of local knowledge on coyote diet in North America, we have little information about how and why diet might vary throughout the species' range.We conducted the first rangewide meta‐analysis of coyote diet by investigating how ecoregion, coyote mass, environmental conditions, presence of top predators and alternative food items are related to coyote dietary diversity, as well as consumption of small mammals, lagomorphs, vegetation and ungulates.Using data from 93 studies, we used generalised linear mixed models to determine which variables best explained coyote dietary patterns.Coyotes were generally more carnivorous in temperate forests than in other ecoregions, primarily due to greater ungulate consumption. Dietary diversity was most influenced via a negative effect of mammal consumption; coyote diet was more diverse in the spring and where human footprint was greater. There was minor variation in small mammal consumption, but lagomorph consumption was greater in spring and winter and when coyotes were larger. Vegetation consumption was greatest in summer and autumn. Ungulate consumption was positively related to coyote mass, snow cover and the presence of grey wolves Canis lupus.Both intrinsic and extrinsic factors were related to coyote diet. Larger coyotes ate larger foods, which parallels the relationship between mass and prey size across the carnivore guild. Wolves and humans have opposing effects on coyote diet. Coyotes seem to prioritise eating wild mammals, though more work is needed to quantify scavenging. Collectively, our findings emphasise the need for continued local or regional studies to understand the highly variable ecological effects of coyotes within the diverse ecosystems they currently inhabit and are poised to inhabit. [ABSTRACT FROM AUTHOR]

Objectives/Hypothesis: To determine the timing of acoustic hearing changes among hearing preservation Cochlear implant (CI) recipients. To determine differences in hearing outcomes based on device type and demographic factors. To determine if there is a relationship between the extent of early hearing loss after CI and the subsequent rate of continued hearing loss. Study Design: Prospective, single subject study. Methods: Two hundred and eleven subjects who received a hearing preservation CI were included in the study—80 Nucleus Hybrid L24 (Cochlear), 47 422/522 (Cochlear), 24 S8 (Cochlear), 14 S12 (Cochlear), 6 SRW (Cochlear), 21 SLIM J (Advanced Bionics), and 19 Flex (Med‐EL). Of these, 127 were included in the subsequent analyses. Audiometric thresholds (low frequency pure‐tone‐averages) were collected and compared pre and postoperatively. Results: Long‐term hearing preservation rates were 65% (52/80) for L24, 83% (20/24) for S8, 79% (11/14) for S12, 83% (5/6) for SRW, 54% (25/47) for 422/522, 91% (21/23) for SLIM J, and 84% (16/19) for Flex. Hearing loss was not related to device type (P =.9105) or gender (P =.2169). Older subjects (age ≥65) had worse hearing outcomes than younger subjects after initial device activation (age <65, P =.0262). There was no significant difference in rate of hearing loss over time between older and younger patients (P =.0938). Initial postoperative hearing loss was not associated with the rate of long‐term hearing loss. Conclusions: Long‐term low frequency hearing preservation is possible for CI recipients and is not associated with gender or device type. Rate of hearing loss over time is not dependent on patient age. Early hearing loss after CI does not predict the rate of long‐term hearing loss. Level of Evidence: 3 Laryngoscope, 132:2036–2043, 2022 [ABSTRACT FROM AUTHOR]

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High‐frequency (20 Hz) aircraft measurements of tropical tropopause layer (TTL) cirrus and humidity are used to examine recent homogeneous freezing ice nucleation events. Several localized regions with peak ice concentrations greater than 10 cm−3 are documented. These high ice concentrations are almost certainly generated by homogeneous freezing of aqueous aerosols. The high‐frequency data reveals considerable structure in the cloud properties and humidity at along‐track scales as short as 8.5 m. Simulations of vapor depletion by growing ice crystals are used to assess the time since nucleation in these high ice concentration patches. Comparisons between observed and simulated dependence of supersaturation on ice concentration indicate the nucleation events occurred within minutes (sometimes only a few minutes) of the aircraft sampling. The infrequency and short ages of the events suggest that the high ice concentrations do not persist for long times, but they may still be important for TTL cirrus microphysical properties by providing a source of ice crystals that can lead to extensive, persistent clouds with lower ice concentrations. We have also used the extensive TTL measurements provided by the high‐altitude aircraft campaigns to evaluate the threshold supersaturation for homogeneous freezing. Peak supersaturations observed are consistent with recent laboratory experiments indicating that ice saturation ratios of about 1.75–1.95 are required for homogeneous freezing of aqueous aerosols at temperatures of 185–200 K. Plain Language Summary: High‐frequency aircraft measurements of cirrus clouds and humidity in the cold, tropical upper troposphere are used to examine recent ice crystal formation events. Several localized regions with very large numbers of small ice crystals are documented. The numerous ice crystals are almost certainly generated by spontaneous freezing of abundant liquid aerosol particles. The high‐frequency data reveals considerable fine‐scale structure in the cloud properties and humidity. Comparisons with calculations of water vapor depletion by growing ice crystals indicate the formation events occurred within minutes (sometimes only a few minutes) of the aircraft sampling. The infrequency and short ages of the events suggest that the high ice number densities do not persist for long times, but they may still be important for cirrus physical properties by providing a source of ice crystals that can lead to extensive, persistent clouds with lower ice numbers. We have also used the extensive measurements provided by the high‐altitude aircraft campaigns to evaluate the threshold conditions for spontaneous freezing of liquid aerosol particles. The threshold conditions are consistent with recent laboratory experiments indicating that substantial super‐cooling must occur before the liquid aerosol particles can freeze. Key Points: High‐frequency airborne cloud and humidity measurements are used to examine high ice concentration events in the tropical tropopause layerThe supersaturation in some of these events indicates that ice nucleation occurred less than 12 min prior to the aircraft samplingPeak supersaturation measurements indicate a higher threshold for homogeneous freezing than previously assumed in models [ABSTRACT FROM AUTHOR]

Seismic hazards in subduction settings typically arise from megathrust, intraslab and crustal earthquake sources. Despite the frequent occurrence of intraslab earthquakes in subduction zones and their potential threat to communities, their long‐term recurrence behaviour is barely studied. Sedimentary sequences in lakes may register ground shaking from different seismic sources. This study investigates two long sediment cores (13 m and 16 m) from Skilak Lake, a proglacial lake in south‐central Alaska, to evaluate whether different seismic sources leave a distinct imprint. The sedimentary record shows a continuously varved sediment sequence, occasionally interrupted by turbidites, slump deposits and tephra beds. Turbidites and slump deposits were objectively identified using a statistical outlier analysis on varve thickness. The earthquake origin of these deposits was ascertained by resemblance with deposits induced by instrumentally recorded earthquakes (for example, 1964 ce Mw 9.2 megathrust and 1954 ce Mw 6.4 intraslab earthquakes) and correlation with multiple coeval landslide deposits on sub‐bottom profiles. The Skilak Lake record chronicles 19 earthquakes with moderate to very high confidence level in the past 1350 years. The sedimentary evidence of instrumentally‐recorded intraslab and megathrust earthquakes within the past 70 years demonstrates that not only megathrust earthquakes, but also past intraslab events are recorded. Although reported seismic intensities at Skilak Lake are comparable for the 1964 ce megathrust and the 1954 ce intraslab earthquakes, the long duration and low frequency content of seismic ground motion during megathrust earthquakes facilitate the triggering of multiple, voluminous landslides and the generation of megaturbidites. In contrast, the shorter duration and higher frequency source spectrum of intraslab earthquakes may only induce surficial slope remobilization and the generation of thinner turbidites. This study demonstrates that the sedimentary record of Skilak Lake has the potential to decipher multiple seismic sources, which opens possibilities for a comprehensive seismic hazard analysis for south‐central Alaska. [ABSTRACT FROM AUTHOR]

The timing of seaward migration is a key life‐history trait for many anadromous fish species, with growth and survival at sea depending on a match/mismatch scenario between the timing of the sea entry and optimal conditions. Based on a 25‐year study with 15,226 individually tagged brown trout (Salmo trutta) in a Norwegian river, we analysed how the within‐season timing of sea migration impacted growth and survival. In both first‐time and veteran migrants, marine growth was highest for early migrating individuals, large individuals, and those with a low condition factor when entering the sea. Survival was highest for individuals entering the sea early in the season. In first‐time migrants, survival increased with body length. Survival also increased with the number of other smolts migrating simultaneously. As the early smolts were the most successful, it may seem strange that many smolts migrate later in the season. We suggest that late‐migrating smolts may not be of a size and/or physiological state suitable for early marine conditions, and may make the best of a bad situation. [ABSTRACT FROM AUTHOR]

A wetland's ability to vertically accrete—capturing sediment and biological matter for soil accumulation—is key for maintaining elevation to counter soil subsidence and sea level rise. Wetland soil accretion is comprised of organic and inorganic components largely governed by net primary productivity and sedimentation. Sea level, land elevation, primary productivity, and sediment accretion are all changing across Louisiana's coastline, destabilizing much of its wetland ecosystems. In coastal Louisiana, analysis from 1984 to 2020 shows an estimated 1940.858 km2 of total loss at an average rate of 53.913 km2/year. Here we hypothesize that remote sensing timeseries data can provide suitable proxies for organic and inorganic accretionary components to estimate local accretion rates. The Landsat catalog offers decades of imagery applicable to tracking land extent changes across coastal Louisiana. This dataset's expansiveness allows it to be combined with the Coastwide Reference Monitoring System's point‐based accretion data. We exported normalized difference vegetation index (NDVI) and red‐band surface reflectance data for every available Landsat 4–8 scene across the coast using Google Earth Engine. Water pixels from the red‐band were transformed into estimates of total suspended solids to represent sediment deposition—the inorganic accretionary component. NDVI values over land pixels were used to estimate bioproductivity—representing accretion's organic component. We then developed a Random Forest regression model that predicts wetland accretion rates (R2 = 0.586, MAE = 0.333 cm/year). This model can inform wetland vulnerability assessments and loss predictions, and is to our knowledge the first remote sensing‐based model that directly estimates accretion rates in coastal wetlands. Plain Language Summary: Soil accretion in coastal wetlands—whereby a wetland area builds its surface by capturing sediment and organic matter—helps counter land loss due to the compaction of soil and sea level rise. Coastal Louisiana has seen significant coastal wetland loss due widespread coastal engineering altering the processes that impact accretion. Remote sensing data can represent these processes, including organic matter production and sediment deposition, but they have not before been applied to directly model accretion rates. Here, we use Landsat timeseries data to model accretion based on derived estimates of suspended sediment availability and bioproductivity. These remote sensing inputs represent the primary inorganic and organic accretionary components, respectively. We additionally track changes in Louisiana's coastal wetland extent from 1984 to 2020 for comparison to our estimated accretion rates, estimating a total of 1940.858 km2 of total loss with a net change accounting for land gain of −1253.130 km2 at a rate of −34.809 km2/year. Our machine learning model results show significant accretion rate declines in coastal regions that experienced the greatest loss over the study period. Our remote sensing‐based model can inform future assessments of wetland vulnerability and loss predictions. Key Points: In Louisiana from 1984 to 2020, we estimated 1940.9 km2 of wetland loss at a 53.9 km2/year rate (net change −1253.1 km2 and −34.8 km2/year)We used machine learning to develop a remote sensing‐based model that directly estimates soil accretion rates in coastal wetlandsAccretion rates have significantly declined in the coastal basins that have lost the most wetland area [ABSTRACT FROM AUTHOR]

The process by which bacterial cells build their intricate flagellar motility apparatuses has long fascinated scientists. Our understanding of this process comes mainly from studies of purified flagella from two species, Escherichia coli and Salmonella enterica. Here, we used electron cryo‐tomography (cryo‐ET) to image the assembly of the flagellar motor in situ in diverse Proteobacteria: Hylemonella gracilis, Helicobacter pylori, Campylobacter jejuni, Pseudomonas aeruginosa, Pseudomonas fluorescens, and Shewanella oneidensis. Our results reveal the in situ structures of flagellar intermediates, beginning with the earliest flagellar type III secretion system core complex (fT3SScc) and MS‐ring. In high‐torque motors of Beta‐, Gamma‐, and Epsilon‐proteobacteria, we discovered novel cytoplasmic rings that interact with the cytoplasmic torque ring formed by FliG. These rings, associated with the MS‐ring, assemble very early and persist until the stators are recruited into their periplasmic ring; in their absence the stator ring does not assemble. By imaging mutants in Helicobacter pylori, we found that the fT3SScc proteins FliO and FliQ are required for the assembly of these novel cytoplasmic rings. Our results show that rather than a simple accretion of components, flagellar motor assembly is a dynamic process in which accessory components interact transiently to assist in building the complex nanomachine. Synopsis: The assembly of bacterial flagellar motors is an "inside‐out" process, starting from the inner membrane. Cryo‐ET reveals novel structures that surround the cytoplasmic C‐ring of high‐torque motors that intriguingly, are only associated with certain assembly stages and are not present in the fully assembled motor. Transient cytoplasmic rings surround the motors of various Beta‐, Gamma‐, and Epsilon‐proteobacteria during assembly.These rings appear to surround the FliG‐ring of the assembling motors.In Helicobacter pylori, these rings are dependent on components of the flagellar type III secretion system. [ABSTRACT FROM AUTHOR]

Chemical modification of proteins has numerous applications, but it has been challenging to achieve the required high degree of selectivity on lysine amino groups. Recently, we described the highly selective acylation of proteins with an N‐terminal Gly‐His6 segment. This tag promoted acylation of the N‐terminal Nα‐amine resulting in stable conjugates. Herein, we report the peptide sequences Hisn‐Lys‐Hism, which we term Lys‐His tags. In combination with simple acylating agents, they facilitate the acylation of the designated Lys Nϵ‐amine under mild conditions and with high selectivity over native Lys residues. We show that the Lys‐His tags, which are 7 to 10 amino acids in length and still act as conventional His tags, can be inserted in proteins at the C‐terminus or in loops, thus providing high flexibility regarding the site of modification. Finally, the selective and efficient acylation of the therapeutic antibody Rituximab, pure or mixed with other proteins, demonstrates the scope of the Lys‐His tag acylation method. [ABSTRACT FROM AUTHOR]

Background: Corticosteroids have been an integral part of maintenance immunosuppression for pediatric kidney transplantation. However, prolonged steroid therapy is associated with significant toxicities resulting in several SW/avoidance strategies in recent years. Method/Objective: This comprehensive review aims to discuss steroid‐related toxicities and the safety, efficacy, and benefit of steroid avoidance/withdrawal immunosuppression in pediatric kidney transplant recipients. Results: Initial studies of SW/avoidance conducted in the setting of CSA and AZA showed an increased incidence of AR but no increase in graft loss or mortality with SW/avoidance maintenance immunosuppression. Studies performed under modern immunosuppression (induction therapy, Tac, and MMF) show no significant increase in AR or graft loss with SW/avoidance immunosuppression. Furthermore, SW/avoidance immunosuppression is associated with significant improvement in growth, BMI, BP control, and lipid profile in pediatric kidney transplant recipients. Despite these data, SW/avoidance remains controversial, and only 40% of pediatric kidney transplant recipients in the United States are currently on SW/avoidance maintenance immunosuppression. Conclusion: SW/avoidance maintenance immunosuppression is safe and associated with fewer side effects compared with steroid‐inclusive maintenance immunosuppression in pediatric kidney transplant recipients. [ABSTRACT FROM AUTHOR]

Cirrus ice crystals are produced heterogeneously on ice‐nucleating particles (INPs) and homogeneously in supercooled liquid solution droplets. They grow by uptake of water molecules from the ice‐supersaturated vapor. The precursor particles, characterized by disparate ice nucleation abilities and number concentrations, compete for available vapor during ice formation events. We investigate cirrus formation events systematically in different temperature and updraft regimes, and for different INP number concentrations and time‐independent nucleation efficiencies. We consider vertical air motion variability due to mesoscale gravity waves and effects of supersaturation‐dependent deposition coefficients for water molecules on ice surfaces. We analyze ice crystal properties to better understand the dynamics of competing nucleation processes. We study the reduction of ice crystal numbers produced by homogeneous freezing due to INPs in both, individual simulations assuming constant updraft speeds and in ensemble simulations based on a stochastic representation of vertical wind speed fluctuations. We simulate and interpret probability distributions of total nucleated ice crystal number concentrations, showing signatures of homogeneous and heterogeneous nucleation. At typically observed, mean updraft speeds (≈15 cm s−1) competing nucleation should occur frequently, even at rather low INP number concentrations (<10 L−1). INPs increase cirrus occurrence and may alter cirrus microphysical properties without entirely suppressing homogeneous freezing events. We suggest to improve ice growth models, especially for low cirrus temperatures (<220 K) and low ice supersaturation (<0.3). Plain Language Summary: Despite decades of research the role of ice‐nucleating particles (INPs) in cirrus formation remains poorly quantified. Our study synthesizes and re‐interprets current knowledge on cirrus formation pathways. We study the competition between liquid particles and INPs in cirrus formation and suggest that competing ice nucleation tends to be more the rule than an exception, except in very clean atmospheric conditions. Despite their low number concentrations, INPs exert a disproportionate influence on microphysical properties of cirrus in the formation stage, for which we provide quantitative evidence. Our work confirms that cirrus formation and vertical air motion variability cannot be considered separately from each other. Deposition of water vapor on ice crystal surfaces constitutes the major growth process for small ice crystals following nucleation. We critically discuss molecular‐level processes controlling cloud ice growth and suggest that current model representation is incomplete, especially in the case of very cold cirrus. Our results and insights aim at improving cirrus parameterization schemes employed in global models and guiding in situ observations and laboratory measurements. Key Points: Competing ice nucleation involving liquid solution droplets and INPs occurs frequently in cirrus formationEven poor INPs influence cirrus formation for moderately high mean updraft speeds and low number concentrationsGrowth of ice crystals by water vapor deposition in low‐temperature cirrus clouds needs further study [ABSTRACT FROM AUTHOR]

Aim: To investigate whether the long‐acting insulin analogue insulin degludec compared with insulin glargine U100 reduces the risk of nocturnal symptomatic hypoglycaemia in patients with type 1 diabetes (T1D). Methods: Adults with T1D and at least one episode of nocturnal severe hypoglycaemia during the last 2 years were included in a 2‐year prospective, randomized, open, multicentre, crossover trial. A total of 149 patients were randomized 1:1 to basal‐bolus therapy with insulin degludec and insulin aspart or insulin glargine U100 and insulin aspart. Each treatment period lasted 1 year and consisted of 3 months of run‐in or crossover followed by 9 months of maintenance. The primary endpoint was the number of blindly adjudicated nocturnal symptomatic hypoglycaemic episodes. Secondary endpoints included the occurrence of severe hypoglycaemia. We analysed all endpoints by intention‐to‐treat. Results: Treatment with insulin degludec resulted in a 28% (95% CI: 9%‐43%; P =.02) relative rate reduction (RRR) of nocturnal symptomatic hypoglycaemia at level 1 (≤3.9 mmol/L), a 37% (95% CI: 16%‐53%; P =.002) RRR at level 2 (≤3.0 mmol/L), and a 35% (95% CI: 1%‐58%; P =.04) RRR in all‐day severe hypoglycaemia compared with insulin glargine U100. Conclusions: Patients with T1D prone to nocturnal severe hypoglycaemia have lower rates of nocturnal symptomatic hypoglycaemia and all‐day severe hypoglycaemia with insulin degludec compared with insulin glargine U100. [ABSTRACT FROM AUTHOR]

Obtaining well diffracting crystals of membrane proteins is often challenging, but chances can be improved by crystallizing them in lipidic conditions that mimic their natural membrane environments. One approach is the high lipid–detergent (HiLiDe) method, which works by mixing the target protein with high concentrations of lipid and detergent prior to crystallization. Although this approach is convenient and flexible, understanding the effects of systematically varying lipid/detergent ratios and a characterization of the lipid phases that form during crystallization would be useful. Here, a HiLiDe phase diagram is reported for the model membrane protein MhsT, which tracks the precipitation and crystallization zones as a function of lipid and detergent concentrations, and is augmented with data on crystal sizes and diffraction properties. Additionally, the crystallization of SERCA1a solubilized directly with native lipids is characterized as a function of detergent concentration. Finally, HiLiDe crystallization drops are analysed with transmission electron microscopy, which among other features reveals liposomes, stacked lamellae that may represent crystal precursors, and mature crystals with clearly discernible packing arrangements. The results emphasize the significance of optimizing lipid/detergent ratios over broad ranges and provide insights into the mechanism of HiLiDe crystallization. [ABSTRACT FROM AUTHOR]

The use of C‐terminal peptide thioesters and hydrazides in synthetic protein chemistry has inspired the search for optimal solid‐phase peptide synthesis (SPPS) strategies for their assembly. However, peptide thioesters are not directly accessible by conventional Fmoc‐SPPS owing to the nucleophilicity of the secondary amine required for Fmoc removal. Here, we report the mild and effective activation of the pGlu linker and a new safety‐catch linker that was used for the convenient synthesis of peptide thioesters and hydrazides via efficient amide‐to‐imide activation followed by nucleophilic displacement. [ABSTRACT FROM AUTHOR]

Advances in immunosuppression have improved graft survival in pediatric kidney transplant recipients; however, treatment‐related toxicities need to be balanced against the possibility of graft rejection. Several immunosuppressive agents are available for use in transplant recipients; however, the optimal combinations of agents remain unclear, resulting in variations in institutional protocols. Lymphocyte‐depleting antibodies, specifically ATG, are the most common induction agent used for pediatric kidney transplantation in the US. Basiliximab may be used for induction in immunologically low‐risk children; however, pediatric data are scarce. CNIs and antiproliferative agents (mostly Tac and mycophenolate in recent years) constitute the backbone of maintenance immunosuppression. Steroid‐avoidance maintenance regimens remain controversial. Belatacept and mTOR inhibitors are used in children under specific circumstances such as non‐adherence or CNI toxicity. This article reviews the indications, mechanism of action, efficacy, dosing, and side effect profiles of various immunosuppressive agents available for pediatric kidney transplantation. [ABSTRACT FROM AUTHOR]

The survival of Atlantic salmon (Salmo salar), an increasingly rare anadromous species, has declined dramatically during its marine phase, with disproportionate impacts on the poorly understood early post‐smolt period. Logistical constraints on collecting oceanic data to inform this issue pose a formidable obstacle. To advance understanding of post‐smolt distributional ecology in the North‐east Atlantic, a comprehensive analysis of existing information was undertaken. Data were synthesized from 385 marine cruises, 10,202 individual trawls, and 9,269 captured post‐smolts, spanning three decades and ~4.75 million km2 of ocean, with 3,423 individuals genetically assigned to regional phylogeographic origin. The findings confirm major migrational post‐smolt aggregations on the continental shelf‐edge off Ireland, Scotland and Norway, and an important marine foraging area in the Norwegian Sea. Genetic analysis shows that aggregational stock composition does not simply reflect distance to natal rivers, with northern phylogeographic stock groups significantly under‐represented in sampled high‐seas aggregations. It identifies a key foraging habitat for southern European post‐smolts located in international waters immediately west of the Vøring Plateau escarpment, potentially exposing them to a high by‐catch mortality from extra‐territorial pelagic fisheries. Evidence of the differential distribution of regional stocks points to fundamental differences in their migration behaviours and may lead to inter‐stock variation in responses to environmental change and marine survival. The study shows that understanding of post‐smolt marine ecology, as regards to stock‐specific variations in habitat utilization, biological performance and exposure to mortality factors, can be significantly advanced by data integration across studies and exploiting genetic approaches. [ABSTRACT FROM AUTHOR]

Despite clinical use of late gadolinium enhancement (LGE) for two decades, an efficient, robust fat suppression (FS) technique still does not exist for this CMR mainstay. In ischemic and non‐ischemic heart disease, differentiating fibrotic tissue from infiltrating and adjacent fat is crucial. Multiple groups have independently developed an FS technique for LGE, double spectral attenuated inversion recovery (DSPAIR), but no comprehensive evaluation was performed. This study aims to fill this gap. DSPAIR uses two SPAIR pulses and one non‐selective IR pulse to enable FS LGE, including compatibility with phase sensitive inversion recovery (PSIR). We implemented a magnitude (MAGN) and a PSIR variant and compared them with LGE without FS (CONTROL) and with spectral presaturation with inversion recovery (SPIR) in simulations, phantoms, and patients. Fat magnetization by SPIR, MAGN DSPAIR, and PSIR DSPAIR was simulated as a function of pulse B1, readout (RO) pulse number, and fat TI. A phantom with fat, fibrosis, and myocardium compartments was imaged using all FS methods and modifying pulse B1, RO pulse number, and heart rate. Signal was measured in SNR units. Fat, myocardium, and fibrosis SNR and fibrosis‐to‐fat CNR were obtained. Patient images were acquired with all FS techniques. Fat, myocardium, and fibrosis SNR, fibrosis‐to‐fat CNR, and image and FS quality were assessed. In the phantom, both DSPAIR variants provided superior FS compared with SPIR, independent of heart rate and RO pulse number. MAGN DSPAIR reduced fat signal by 99% compared with CONTROL, PSIR DSPAIR by 116%, and SPIR by 67% (25 RO pulses). In patients, both DSPAIR variants substantially reduced fat signal (MAGN DSPAIR by 87.1% ± 10.0%, PSIR DSPAIR by 130.5% ± 36.3%), but SPIR did not (35.8% ± 25.5%). FS quality was good to excellent for MAGN and PSIR DSPAIR, and moderate to poor for SPIR. DSPAIR provided highly effective FS across a wide range of parameters. PSIR DSPAIR performed best. [ABSTRACT FROM AUTHOR]

Structure‐determination methods are needed to resolve the atomic details that underlie protein function. X‐ray crystallography has provided most of our knowledge of protein structure, but is constrained by the need for large, well ordered crystals and the loss of phase information. The rapidly developing methods of serial femtosecond crystallography, micro‐electron diffraction and single‐particle reconstruction circumvent the first of these limitations by enabling data collection from nanocrystals or purified proteins. However, the first two methods also suffer from the phase problem, while many proteins fall below the molecular‐weight threshold required for single‐particle reconstruction. Cryo‐electron tomography of protein nanocrystals has the potential to overcome these obstacles of mainstream structure‐determination methods. Here, a data‐processing scheme is presented that combines routines from X‐ray crystallography and new algorithms that have been developed to solve structures from tomograms of nanocrystals. This pipeline handles image‐processing challenges specific to tomographic sampling of periodic specimens and is validated using simulated crystals. The tolerance of this workflow to the effects of radiation damage is also assessed. The simulations indicate a trade‐off between a wider tilt range to facilitate merging data from multiple tomograms and a smaller tilt increment to improve phase accuracy. Since phase errors, but not merging errors, can be overcome with additional data sets, these results recommend distributing the dose over a wide angular range rather than using a finer sampling interval to solve the protein structure. [ABSTRACT FROM AUTHOR]

Gas vesicles (GVs) are cylindrical or spindle‐shaped protein nanostructures filled with air and used for flotation by various cyanobacteria, heterotrophic bacteria, and Archaea. Recently, GVs have gained interest in biotechnology applications due to their ability to serve as imaging agents and actuators for ultrasound, magnetic resonance and several optical techniques. The diameter of GVs is a crucial parameter contributing to their mechanical stability, buoyancy function and evolution in host cells, as well as their properties in imaging applications. Despite its importance, reported diameters for the same types of GV differ depending on the method used for its assessment. Here, we provide an explanation for these discrepancies and utilize electron microscopy (EM) techniques to accurately estimate the diameter of the most commonly studied types of GVs. We show that during air drying on the EM grid, GVs flatten, leading to a ~1.5‐fold increase in their apparent diameter. We demonstrate that GVs' diameter can be accurately determined by direct measurements from cryo‐EM samples or alternatively indirectly derived from widths of flat collapsed and negatively stained GVs. Our findings help explain the inconsistency in previously reported data and provide accurate methods to measure GVs dimensions. [ABSTRACT FROM AUTHOR]

Background: Stress is commonly experienced by college students, especially engineering students. However, the role of stress within engineering culture and its implications for engineering programs have not been fully explored in the literature. Purpose/Hypothesis: The purpose of this study was to measure and examine the relationships among self‐reported stress, anxiety, and depression; engineering identity; and perceptions of inclusion of undergraduate engineering students. Design/Method: We validated a quantitative survey instrument built on previously published scales and used it to measure self‐reported stress, anxiety, and depression; engineering identity; and perceptions of inclusion. Results: Our findings indicate that self‐reported levels of stress, anxiety, and depression are high for engineering students. Further, levels of stress and anxiety are significantly higher for female students, while levels of depression are higher for first‐generation students. We find correlations between self‐reported mental health symptoms, engineering identity, and perceptions of inclusion, and these relationships differ by gender. Lastly, we find that students underrepresented in engineering rate their departments as less diverse than their peers. Conclusions: Our results suggest that perceptions of inclusion and engineering identity are related to student mental health, further emphasizing the importance of developing inclusive cultures in engineering programs. The findings suggest that mental health needs greater attention in engineering education, particularly for female and first‐generation students. [ABSTRACT FROM AUTHOR]

Rapid phenotypic stock identification in mixed-stock fisheries can provide a useful alternative to more time-intensive methods (e.g., coded wire tags, genetics) in assessing harvest and informing management decisions. We leveraged local ecological knowledge, existing stock identification methods, and understanding of life history differences to develop rapid stock identification tools for fall-run Chinook Salmon Oncorhynchus tshawytscha encountered in the Buoy 10 recreational fishery at the mouth of the Columbia River. Specifically, we sought to differentiate between the fishery’s two dominant genetic lineages: lower river tules and upriver brights. We sampled recreationally landed Chinook Salmon in 2017, 2018, and 2019, assigned sampled individuals to functional reporting groups using a single-nucleotide-polymorphism-based genetic baseline, and collected measurements on phenotypic traits. Using traits including pigmentation patterns (e.g., spotting), fin morphology, characteristics indicative of sexual maturity, and muscle lipid content, random forest classification models provided consistently high classification success across and within genetic groups (i.e., up to 90%). Classification success remained consistent over time within fishery seasons and between years but showed meaningful bias between sexes. Based on observed classification success, we developed and evaluated a categorical visual identification guide capable of facilitating more rapid trait observations and on-site stock identification. The resulting classification key, built using classification trees and visual guide observations from 2019, achieved slightly lower classification success across and within genetic groups and had variable success among samplers. Compared with the existing use of coded wire tags in harvest assessment, phenotypic stock identification methods can provide more rapid and more numerous assignments, albeit with a greater degree of individual assignment error. Applied as a complement to standard methods like coded wire tags, the use of rapid phenotypic stock identification methods offers the potential for increased overall precision and timeliness in harvest assessments. [ABSTRACT FROM AUTHOR]

A nascent in situ cirrus was observed on January 11, 2019 in the tropical tropopause layer (TTL) over the southwestern Indian Ocean, with the use of balloon‐borne instruments. Data from cryogenic frost point hygrometer (CFH) and Compact Optical Backscatter and AerosoL Detector (COBALD) instruments were used to characterize the cirrus and its environment. Optical modeling was employed to estimate the cirrus microphysical properties from the COBALD backscatter measurements. Newly fomed ice crystals with radius <1 μm and concentration ∼500 L−1 were reported at the tropopause. The relatively low concentration and CFH ice supersaturation (1.5) suggests a homogeneous freezing event stalled by a high‐frequency gravity wave. The observed vertical wind speed and temperature anomalies that triggered the cirrus formation were due to a 1.5‐km vertical‐scale wave, as shown by a spectral analysis. This cirrus observation shortly after nucleation is beyond remote sensing capabilities and presents a type of cirrus never reported before. Plain Language Summary: Ice clouds are very common in the tropical tropopause layer, a layer of the atmosphere between 14 and 18 km separating the troposphere and the stratosphere. Ice clouds can be formed in situ, generated by cold temperature anomalies due to atmospheric disturbances. In this observational study, we use data from instruments that were flown on the same balloon on January 11, 2019 from Réunion Island, in the southwestern Indian Ocean. We report an ice cloud at the tropopause, at ∼16.5 km, composed of ice particles with a concentration of more than 500 per liter. This suggests that the ice cloud formed by homogeneous freezing, that is, the freezing of airborne aqueous solutions. In addition, an abrupt increase in ascent rate of the balloon is related to an atmospheric disturbance which cooled the air and possibly led to the ice cloud formation. The tiny size of the ice crystals indicates that they have just formed. This is a very rare observation because nucleation events are very short. Key Points: First in situ observation of a nascent tropical tropopause cirrusHomogeneous formation of tiny ice crystals (<1 μm) is due to a short vertical scale gravity wave at the tropopauseSuch optically thin cirrus clouds would be missed by current aircraft instruments/remote sensing systems [ABSTRACT FROM AUTHOR]

A glucose responsive insulin (GRI) that responds to changes in blood glucose concentrations has remained an elusive goal. Here we describe the development of glucose cleavable linkers based on hydrazone and thiazolidine structures. We developed linkers with low levels of spontaneous hydrolysis but increased level of hydrolysis with rising concentrations of glucose, which demonstrated their glucose responsiveness in vitro. Lipidated hydrazones and thiazolidines were conjugated to the LysB29 side‐chain of HI by pH‐controlled acylations providing GRIs with glucose responsiveness confirmed in vitro for thiazolidines. Clamp studies showed increased glucose infusion at hyperglycemic conditions for one GRI indicative of a true glucose response. The glucose responsive cleavable linker in these GRIs allow changes in glucose levels to drive the release of active insulin from a circulating depot. We have demonstrated an unprecedented, chemically responsive linker concept for biopharmaceuticals. [ABSTRACT FROM AUTHOR]

Genetic methods can guide and improve the management of recreational mixed‐stock fisheries by informing stock‐specific estimates of harvest. We applied genetic stock identification and parentage‐based tagging to a recreational Chinook Salmon Oncorhynchus tshawytscha fishery in the Columbia River to illustrate the value of genetic analysis in management. We sampled landed catch in 2017 and 2018, assigned the fish to genetic reporting groups, explored temporal trends in harvest composition within and between seasons, and assessed the accuracy and precision of genetic methods against estimates from conventional tagging methodology. The genetic stock identification and parentage‐based tagging produced concordant stock assignments, and the harvest composition estimates were validated with independent data. High assignment rates, relative to expended sampling effort, and precise harvest composition estimates with adequate sample sizes demonstrate that both genetic methods can be complementary, effective tools in advancing harvest assessment and recreational fisheries management. The success of genetic stock identification and parentage‐based tagging supports the expanded application of genetics to similar fisheries, potentially alongside existing or emerging assessment methods, and guides future improvements in data collection and analysis. [ABSTRACT FROM AUTHOR]

Attachment of cationic moieties to oligonucleotides (ONs) promises not only to increase the binding affinity of antisense ONs by reducing charge repulsion between the two negatively charged strands of a duplex, but also to augment their in vivo stability against nucleases. In this study, polyamine functionality was introduced into ONs by means of 2′‐amino‐LNA scaffolds. The resulting ONs exhibited efficient binding towards ssDNA, ssRNA and dsDNA targets, and the 2′‐amino‐LNA analogue carrying a triaminated linker showed the most pronounced duplex‐ and triplex‐stabilizing effect. Molecular modelling revealed that favourable conformational and electrostatic effects led to salt‐bridge formation between positively charged polyamine moieties and the Watson–Hoogsteen groove of the dsDNA targets, resulting in the observed triplex stabilization. All the investigated monomers showed increased resistance against 3′‐nucleolytic digestion relative to the non‐functionalized controls. [ABSTRACT FROM AUTHOR]

The use of silicon (Si) in the form of nanoparticles is one of the most promising routes for boosting the capacity of modern Li‐ion batteries. Many parameters influence the performance of Si making the comparison of materials complicated. The present work demonstrates a direct comparison of Si nanoparticles with amorphous and crystalline structures prepared through the same chemistry with the same particle size and morphology. The amorphous Si nanoparticles with an average diameter of 100 nm were synthesized through silane pyrolysis, and their crystalline analogues were obtained through subsequent annealing not altering size or morphology of the nanoparticles. Such direct comparison allows evaluation of the specific impact of crystallinity on the material's performance. From electrochemical analysis of these materials, the electrodes prepared from amorphous nanoparticles were found to exhibit improved cycle life compared to electrodes prepared from crystalline nanoparticles when the delithiation capacity of the anode was limited to 1000 mAh/gSi. [ABSTRACT FROM AUTHOR]