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The impact of unintentional incorporation of Sb in the tensile InAs layer of type-II strain-balanced InAs/InAsSb superlattices is investigated. Several coherently strained midwave and longwave superlattices are grown on (100) GaSb substrates by molecular beam epitaxy and examined using x-ray diffraction and temperature-dependent photoluminescence spectroscopy. The zero-order diffraction angle provides the average Sb mole fraction of the strain-balanced superlattice period. Analysis of the higher order diffraction angles, along with the individual layer growth times and strain, provides the InAs and InAsSb layer thicknesses. Analysis of the photoluminescence measurements provides the ground-state bandgap of the superlattice, which along with simulations of the ground-state energies of the electrons and holes using a Kronig–Penney model, specify how the Sb is distributed between the tensile and compressive layers of the period and ultimately the quantity of unintentional Sb in the InAs layer. The unintentional Sb mole fractions observed in the tensile InAs layers are 1.9% for midwave and 1.2% for longwave. When compared to superlattices with the same period and no Sb in the tensile layer, the presence of unintentional Sb blue-shifts the 77 K temperature cutoff wavelength from 6.3 to 5.3 μm for midwave and from 18.8 to 12.0 μm for longwave. [ABSTRACT FROM AUTHOR]

Capacitance–voltage measurements are a powerful technique to determine doping profiles of semiconductor pn junctions and Schottky barrier diodes. The measurements were recently extended to III-V-based mid-wavelength nBn infrared detectors, and absorber doping densities have been extracted using the widely accepted Schottky approximation, where the potential drop across the device is assumed to be across the depleting absorber layer. However, this approach is limited to when the absorber region of the nBn is under high reverse bias and thus is only able to extract the absorber region doping profile. Here, we introduce a semi-analytical model that is capable of extracting barrier dopant polarity, doping concentration, and thickness, as well as contact and absorber layer doping concentrations, all from a capacitance–voltage measurement. Rather than solely considering the potential drop across the depleting layers, it considers the potential drop across the accumulating layer as well. This negative charge accumulation occurs for the contact and absorber layers in the case of reverse and forward biases, respectively. This allows for a single model to be applied to a capacitance–voltage curve at forward and reverse biases and it can provide regions of bias where the absorber transitions from depletion to accumulation. We compare the agreement of the semianalytical model with modeling results from commercially available finite element method software and experimental capacitance–voltage data. Finally, we show that the method is consistent with the Schottky approximation of extracting absorber doping densities at high reverse bias and discuss the model's limitations. [ABSTRACT FROM AUTHOR]

Background: Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have been shown to improve outcomes in patients with heart failure (HF) and are now included in guideline-directed medical therapy. Trials reporting the change in loop diuretic dose following SGLT2i initiation have indicated conflicting results. There is no clear guidance on whether reducing loop diuretic doses following SGLT2i initiation is appropriate. Objective: The purpose of this study is to assess the impact of SGLT2i initiation on diuretic adjustment in hospitalized patients with known or new HF. Methods: This was a retrospective, single health-system study assessing the change in loop diuretic dose in the 60 days following discharge for patients with HF initiated on SGLT2i therapy during a hospital admission or upon discharge. Secondary outcomes assessed effect on renal function and discontinuation of SGLT2i within the 60 day follow up period. Results: Forty percent of patients required loop diuretic dose adjustment, with 29% requiring a dose reduction within the 60 days following discharge. There was minimal change in serum creatinine or blood urea nitrogen. The SGLT2i was discontinued in 6 patients. Conclusions: After inpatient initiation of SGLT2is, approximately one-third of patients required a reduction in loop diuretic dose within 60 days following hospital discharge. Further study is recommended to confirm if empiric diuretic dose adjustments are appropriate in this HF population. [ABSTRACT FROM AUTHOR]

Conventional structures associated with stream crossings such as bridges and culverts can lead to zones of high-velocity water flow that impede fish passage. Such obstacles are likely to harm native fish populations by impacting migrations critical to their life history strategies, causing habitat fragmentation and extirpation, thereby limiting population growth and distribution. Due to the high rates of human population growth and development occurring in Texas, this is an issue of particular concern for fish designated as species of greatest conservation need (SGCN). This project focused on four SGCN fishes native to the Edwards Plateau Ecoregion, namely the Guadalupe Bass, Guadalupe Roundnose Minnow, Guadalupe Darter, and Plateau Shiner, at both adult (all species) and juvenile (Guadalupe Bass only) life stages. Our primary aim was to aid in the design of future culverts associated with stream crossings (or the modification of existing culverts) so that the water velocities through these structures do not exceed the swimming capacities of our target SGCN fishes. To this end, we assessed their maximum sustained swimming speeds (Ucrit) under a typical range of Edwards Plateau stream temperatures (15, 22.5, and 30 °C) to be used in site-specific calculations of the maximum allowable culvert water velocities (Vf). A secondary objective was to collect physiological endpoints of relevance to the overall swimming performance including the maximum burst swimming speeds (Umax), metabolic rate measurements (i.e., standard metabolic rate (SMR), maximum metabolic rate (MMR), and aerobic scope (AS)), cost of transport (COT), and optimal swimming speed (Uopt). Temperature-related effects were observed that can be used to inform site-specific culvert designs. In general, the highest Ucrit values for the tested species were near, or possibly between, 22.5 and 30 °C, while Umax stayed relatively consistent among treatments. [ABSTRACT FROM AUTHOR]

A minority carrier lifetime of 2.7 ns is measured at 77 K for a GeSn/SiGeSn single quantum well using time-resolved photoluminescence, and subsequent analyses indicate that the lifetime is Auger-limited. The 77 K lifetime is evaluated as a function of stepwise dose of 63 MeV proton irradiation up to a fluence of 1.5 × 1012 p+/cm2 with no discernable reduction in the observed lifetime, which implies that the lifetime damage factor slope to 63 MeV proton irradiation is not greater than 2 × 10−5 cm2/s. Steady-state photoluminescence is used to evaluate the total luminescence output as a function of excitation, yielding a 2/3 power law slope consistent with Auger-limited recombination. The observed Auger-limited behavior is consistent with reports of high p-type background carrier concentration in these alloys. The temperature dependence of the steady-state photoluminescence spectra also provides the Einstein single oscillator model parameters for the ground state transition energy and Urbach energy of the GeSn quantum well. [ABSTRACT FROM AUTHOR]

We investigate the bulk passivation of the dilute bismide alloy InAsSbBi by plasma-assisted hydrogenation. InAsSbBi is of significant interest for mid- to long-wave infrared photodetection due to its bandgap flexibility and potential integration with heterostructured photodetector architectures. Epitaxially grown InAsSbBi samples are characterized by photoluminescence and time-resolved photoluminescence measurements for a range of hydrogenation conditions. Increases in the minority carrier lifetime of over 3 × are reported, with no degradation over a period of months following the treatment. Photoluminescence measurements confirm that the hydrogenation process improves the InAsSbBi optical properties. These results offer a path toward the improved performance of InAsSbBi-based photodetectors and potentially other narrow bandgap semiconductor materials and material systems. [ABSTRACT FROM AUTHOR]

Utilizing reflectance spectroscopy to generate the necessary soil data to drive innovations in precision agriculture and soil management is an increasing focus of agronomic research. One of the key limitations for widespread practical adoption of reflectance spectroscopy is hardware cost, and lower cost hardware is actively being developed. This study evaluated two inexpensive nano Fourier‐transform near infrared spectrometers in the laboratory. One was a laboratory‐based analyzer (LabFlow) and the second was a field portable analyzer (Field Probe). Soil spectra were collected in the shortwave infrared range and processed using wavelet transforms and machine learning models. The optimal wavelet transforms and machine learning model were selected using cross validation on the training dataset, and performance of the optimal model was evaluated using an independent testing dataset. The Field Probe configuration total nitrogen model had the best performance when compared to the LabFlow laboratory analyzer with an R2 of 0.91, a concordance correlation coefficient of 0.95, and an root mean square error of 0.03. Soil inorganic carbon did not perform as well with an R2 of 0.65. However, performance was likely limited by a large number of low values and a limited range in the training dataset. Overall, these results highlight the potential for lower cost spectrometers to provide useful soil data for soil management applications. Core Ideas: There is a potential for low‐cost spectrometers to provide useful soil data for soil management applications.Optimal signal processing, model type, and model hyperparameters are dataset specific.Error in reference values is important to consider regarding model performance. [ABSTRACT FROM AUTHOR]

A microscopy platform that leverages the arrival time of individual photons to enable 3D single-particle tracking of fast-moving (translational diffusion coefficient of ≃3.3 µm2/s) particles in high-background environments is reported here. It combines a hardware-based time-gating module, which enables the rate of photon processing to be as high as 100 MHz, with a two-photon-excited 3D single-particle tracking confocal microscope to enable high sample penetration depth. Proof-of-principle experiments where single quantum dots are tracked in solutions containing dye-stained cellulose, are shown with tracking performance markedly improved using the hardware-based time-gating module. Such a microscope design is anticipated to be of use to a variety of communities who wish to track single particles in cellular environments, which commonly have high fluorescence and scattering background. [ABSTRACT FROM AUTHOR]

Semiconductor-based mid-wave infrared photon detectors that functionalize space-based imaging systems are susceptible to both cumulative ionization and displacement damage, especially due to proton irradiation. Here, the dark current density and quantum efficiency of a mid-wave infrared detector utilizing a strain-balanced InGaAs/InAsSb superlattice active region are examined as a function of a 63 MeV proton radiation dose. Proton-irradiation is performed in an incremental stepwise dose up to a total ionizing dose of 100 krad(Si) or an equivalent proton fluence of 6.1 × 1011 protons/cm2. All characterization work is conducted with the detectors held at an operating temperature of 130 K throughout the experiment to limit thermal annealing effects. Prior to irradiation, the quantum efficiency of the top-side illuminated device without anti-reflection coating is 59.5%. The quantum efficiency is largely independent of temperature below 150 K, indicative of an electron minority carrier. As irradiation progressed the typical linear increase in inverse quantum efficiency with increasing proton fluence was observed, which led to a quantum efficiency damage factor of 1.12 × 1013 e cm2/ph. This value is shown to be an order of magnitude lower than typically observed in III-V nBn devices and is likely due to the higher mobility of minority electrons in the active region of this device. A full analysis of the characterization results suggests that displacement damage creates a significant population of donor states that modify the doping profile, in addition to Shockley–Read–Hall recombination centers that generally form as a result of proton irradiation. [ABSTRACT FROM AUTHOR]

Gallium is incorporated into the strain-balanced In(Ga)As/InAsSb superlattice system to achieve the same mid-wave infrared cutoff tunability as conventional Ga-free InAs/InAsSb type-II superlattices, but with an additional degree of design freedom to enable optimization of absorption and transport properties. Time-resolved photoluminescence measurements of InGaAs/InAsSb superlattice characterization- and doped device structures are reported from 77 to 300 K and compared to InAs/InAsSb. The low-injection photoluminescence decay yields the minority carrier lifetime, which is analyzed with a recombination rate model, enabling the determination of the temperature-dependent Shockley–Read–Hall, radiative, and Auger recombination lifetimes and extraction of defect energy levels and capture cross section defect concentration products. The Shockley–Read–Hall-limited lifetime of undoped InGaAs/InAsSb is marginally reduced from 2.3 to 1.4 μs due to the inclusion of Ga; however, given that Ga improves the vertical hole mobility by a factor of >10×, a diffusion-limited InGaAs/InAsSb superlattice nBn could expect a lower bound of 2.5× improvement in diffusion length with significant impact on photodetector quantum efficiency and radiation hardness. At temperatures below 120 K, the doped device structures are Shockley–Read–Hall limited at 0.5 μs, which shows promise for detector applications. [ABSTRACT FROM AUTHOR]

Background: Antiretroviral therapy (ART) has led to a decline in human immunodeficiency virus (HIV)-related mortality, but comorbidities, including organ dysfunction, are increasingly the focus of care. Heart transplant (HT) is a very effective therapeutic strategy for end-stage heart failure (HF); however, clinicians may be hesitant due to concerns of complex drug-drug interactions (DDIs) between ART and HT immunosuppressive regimens and the potential impact of ART on long-term HT outcomes. In this report, we describe long-term (76-month) follow-up of a patient with HIV-positive status who underwent orthotopic HT with special emphasis on complex drug interactions. Case presentation: A 58-year-old man with HIV-1 developed ischemic cardiomyopathy, progressed to end-stage HF and underwent orthotopic HT. To avoid DDIs with planned immunosuppressive therapies, the ART regimen was modified to consist of lamivudine, tenofovir disoproxil fumarate, rilpivirine, and raltegravir. Following HT, the patient's immunosuppression consisted of tacrolimus and mycophenolate mofetil. He has had normal cardiac function and no opportunistic infections and was subsequently switched to tenofovir alafenamide, emtricitabine, and bictegravir in combination for convenience. Serial HIV-1 RNA blood levels were constantly below the limit of quantification, and his CD4 count remained above 200 cells/mm3 (30–35%). Several DDIs were identified and addressed; however, his long-term post-HT complications included one episode of asymptomatic acute cellular rejection, adenocarcinoma of the prostate, basal cell carcinoma, cardiac allograft vasculopathy, and peripheral neuropathy. Conclusion: The clinical outcome of this case supports the conclusion of previously published reports, summarized here within, demonstrating that HIV-1 positive status should not preclude HT in carefully selected individuals. Both addressing potential DDIs prior to HT and long-term monitoring for routine post-transplant complications and secondary and incidental malignancies are imperative. [ABSTRACT FROM AUTHOR]

Seasonal movements cued by environmental variables are a critical component of riverine fish life history. Life‐history events for species such as blue sucker Cycleptus elongatus are likely cued by discharge and temperature and may be disrupted if those life‐history events and environmental regimes are mismatched. However, this effect may be dependent upon the habitat occupied when environmental cues are received by individuals. We tracked telemetered blue sucker in the Colorado River, Texas, USA, from 2015 to 2017 and modelled the relative effects of discharge, temperature and habitat structure on seasonal movement patterns. Tagged fish varied in their propensity to move, although most returned to their original tagging locations. Decreasing temperatures and increasing discharge resulted in increased seasonal movements. Temperature and discharge had the largest effect on movement behaviour, but the magnitude of movements was largely dependent on the year. Temperatures between 12 and 19°C and discharges between 10 and 240 m3s−1 resulted in greater probabilities of spawning movements. Spawning was most probable in 2015 and reduced or halted in 2016 and 2017. Future climate scenarios suggest North America will experience increased drought, warmer temperatures and more variable weather patterns. These future scenarios could negatively impact blue sucker by disrupting environmental cues and habitat availability for seasonal life‐history events. Our results suggest temperature and discharge are critical cues for the species, but that their combined effect is largely dependent on the occupied habitat. [ABSTRACT FROM AUTHOR]

A multipurpose imaging x-ray crystal spectrometer is developed for the high energy density instrument of the European X-ray Free Electron Laser. The spectrometer is designed to measure x rays in the energy range of 4–10 keV, providing high-resolution, spatially resolved spectral measurements. A toroidally bent germanium (Ge) crystal is used, allowing x-ray diffraction from the crystal to image along a one-dimensional spatial profile while spectrally resolving along the other. A detailed geometrical analysis is performed to determine the curvature of the crystal. The theoretical performance of the spectrometer in various configurations is calculated by ray-tracing simulations. The key properties of the spectrometer, including the spectral and spatial resolution, are demonstrated experimentally on different platforms. Experimental results prove that this Ge spectrometer is a powerful tool for spatially resolved measurements of x-ray emission, scattering, or absorption spectra in high energy density physics. [ABSTRACT FROM AUTHOR]

The sensitivity of III-V-based infrared detectors is critically dependent upon the carrier concentration and mobility of the absorber layer, and thus, accurate knowledge of each is required to design structures for maximum detector performance. Here, measurements of the bulk in-plane resistivity, in-plane mobility, and carrier concentration as a function of temperature are reported for non-intentionally doped and Si-doped mid-wave infrared InAs0.91Sb0.09 alloy and InAs/InAs0.65Sb0.35 type-II superlattice materials grown on GaSb substrates. Standard temperature- and magnetic-field-dependent resistivity and the Hall measurements on mesa samples in the van der Pauw configuration are performed, and multicarrier fitting and modelling are used to isolate transport of each carrier species. The results show that up to 5 carrier species of the surface, interface and bulk variety contribute to conduction, with bulk electron and hole mobility up to 2·105 cm2/V s and 8·103 cm2/V s, respectively and background dopant concentration levels were between 1014 and 1015 cm-3. The in-plane mobility temperatures dependence is determined and trends of each carrier species with temperature and dose are analysed. [ABSTRACT FROM AUTHOR]

There is increasing demand for more detailed soil maps to support fine-scale land use planning, soil carbon management, and precision agriculture in Saskatchewan. Predictive soil mapping that incorporates a combination of environmental covariates provides a cost-effective tool for generating finer resolution soil maps. This study focused on mapping soil properties for multiple soil horizons in Saskatchewan using historical legacy soil data in combination with remote sensing band indices, bare soil composite imagery, climate data, and terrain attributes. Mapped soil properties included soil organic carbon content (SOC), total nitrogen, cation exchange capacity (CEC), electrical conductivity (EC), inorganic carbon (IOC), sand and clay content, and total profile soil organic carbon stocks. For each of these soil properties, a recursive feature elimination was undertaken to reduce the number of features in the overall model. This process involved iteratively removing features such that random forest out-of-bag error was minimized. Final random forest models were built for each property and evaluated using an independent test dataset. Overall, predictive models were successful for SOC (R2 = 0.71), total nitrogen (R2 = 0.65), CEC (R2 = 0.46), sand content (R2 = 0.44) and clay content (R2 = 0.55). The methods used in this study enable mapping of a greater geographic region of Saskatchewan compared to those previously established that relied solely on bare soil composite imagery. [ABSTRACT FROM AUTHOR]

Since initial publication of the PARADIGM‐HF trial in 2014, sacubitril/valsartan has been investigated in various settings to establish optimal use, further expanding its indications in patients with heart failure (HF). Although numerous studies have been published, until recently these have primarily involved post hoc analyses from the PARADIGM‐HF study itself with a consistent focus on use of sacubitril/valsartan in patients with HF with reduced ejection fraction (HFrEF). This has led to a gap in the literature regarding utility of sacubitril/valsartan in other HF subpopulations. The aim of this review is to provide a summary of recent clinical trials further expanding use and guideline recommendations for sacubitril/valsartan. The findings of 15 studies, including clinical trials and post hoc analyses, are summarized and describe the use of sacubitril/valsartan in additional HF subpopulations, such as HFrEF following hospitalization for acute decompensated HF and advanced HF, HF with preserved ejection fraction (HFpEF), and HF postmyocardial infarction. In addition, three studies investigating timing of initiation, dose titration regimens, and cost‐effectiveness are examined. Select ongoing trials are also reviewed to demonstrate the continued commitment to further advance care of patients with HF. This comprehensive review serves as a resource for health care providers who pursue optimal utilization of sacubitril/valsartan in their respective clinical practices. [ABSTRACT FROM AUTHOR]

We used stable isotope analysis to investigate differences in Guadalupe bass (Micropterus treculii) resource use that might be associated with population‐level variation in mainstem river versus tributary stream habitats. Guadalupe bass from mainstem sites had higher δ13C and δ15N values compared to those collected in tributaries, likely reflecting greater importance of algae as a basal resource and influences of urban wastewater in mainstem habitats. Documenting ecological variation across ecosystem types is important to inform fish conservation efforts, especially for species that occupy a range of stream sizes. [ABSTRACT FROM AUTHOR]

We have used a recently developed approach that employs first-principles Hamiltonians, tight-binding Hamiltonians, and Green's function methods to study the effect of (a) interfacial strain and (b) Ga on lifetime-limiting native point defect states in InAs/InAsSb, 2% Sb-diffused InAs/InAsSb, and InGaAs/InAsSb superlattices strain-balanced on GaSb. All designs are chosen to have near-identical band gap in the mid-wave infrared band. We considered vacancies and antisites of anions and cations located at the interfaces and at the interior of the superlattice and calculated both defect levels and formation energies. Our calculations do not predict any lifetime-killing native point defects in InGaAs/InAsSb whether or not Sb is allowed to diffuse and create new defects in the InGaAs region. In contrast, we predict a sizable number of lifetime-killing defects near the interface in InAs/InAsSb, and interestingly, they are not present when InAs is replaced by InAs0.98As0.02, suggesting that the strain in the InAsSb region could be the origin of the defects in InAs-based SLS. Our calculations in both InAs0.98Sb0.02/InAsSb and InGaAs/InAsSb superlattices are consistent with reported long lifetimes measured in those material systems. [ABSTRACT FROM AUTHOR]

Summary: Background: Causes of abnormal behaviour during tacking‐up or mounting are multifactorial, but may be associated with an ill‐fitting saddle, a rider sitting on the caudal third of the saddle, or lameness. Objectives: To determine whether: (1) owners believed their horse showed abnormal behaviour when tacked‐up or mounted; (2) this agreed with observations by a veterinarian. Study design: Cross‐sectional study; convenience sample. Methods: Horses were undergoing prepurchase examinations, investigation of poor performance, or were recruited by invitation. Owners were asked if their horse showed abnormal behaviour when tacked‐up or mounted and subsequently whether they showed specific behaviours (yes/no) during bridling, saddling, girthing and mounting. Each horse was observed during tacking‐up and mounting by one veterinarian who recorded the occurrence of each behaviour. Agreement between the owners and the veterinarian was evaluated using intraclass correlation (ICC) coefficients with 95% confidence intervals (CI). Results: Overall 34.2% (66/193) of owners reported that their horse showed behavioural abnormalities during tacking‐up or mounting. There was poor to good agreement between the owners and veterinarian for horses putting their head up to avoid bridling (ICC 0.53, CI 0.37, 0.64) and being reluctant to open their mouth for the bit (ICC 0.52, CI 0.36, 0.64). There was poor to fair agreement for evading noseband tightening (ICC 0.41, CI 0.21, 0.56), elevating the head (ICC 0.24, CI 0.00, 0.43) and teeth grinding (ICC 0.23, CI 0.00, 0.42). For attempts to bite, there was fair to excellent agreement during saddling (ICC 0.67, CI 0.56, 0.75) and good to excellent agreement during girthing (ICC 0.73, CI 0.64, 0.79). Results for some behaviours suggested potential systematic disagreement between the veterinarian and owners. Main limitations: Potential bias of volunteers recruited by invitation. Day‐to‐day variation of behaviours is unknown. Conclusions: The majority of owners were unaware that their horses showed behavioural abnormalities during tacking‐up or mounting. [ABSTRACT FROM AUTHOR]

Featured Application: Deep-level transient spectroscopy; any applications requiring extraction of rate and initial value of decaying exponentials. A mathematical method is presented for the extraction of defect parameters from the multiexponential decays generated during deep-level transient spectroscopy experiments. Such transient phenomenon results from the ionization of charge trapped in defects located in the depletion width of a semiconductor diode. From digitized transients acquired at fixed temperatures, this method produces a rate–domain spectral signature associated with all defects in the semiconductor. For signal-to-noise ratio of 1000, defect levels with carrier emission rates differing by as little as 1.5 times may be distinguished. [ABSTRACT FROM AUTHOR]

Summary: Background: There has been no large‐scale, evidence‐based study on horses' behaviour while being tacked ‐up or mounted. Objectives: To describe equine behaviour during tacking‐up and mounting. Study design: Cross‐sectional, prospective observational study, using a convenience sample. Methods: A purpose‐designed protocol for documenting behaviour during tacking‐up and mounting was developed. Horses were recruited from 11 locations, from both amateur and professional riders. Horses (n = 193) were observed during acquisition of predefined information from the owners. Behaviour data were recorded during bridling, placement of the saddle, girthing and mounting. Results: The majority (67%) were bridled first. The median sum of abnormal behaviours during tacking‐up was 10/64 (interquartile range [IQR] 7.13; range 0.33). There was an equal frequency of abnormal behaviours during bridling and saddling in 52% of horses; 34% of horses showed more abnormal behaviours during saddling than bridling; 15% of horses showed more abnormal behaviours during bridling than saddling. The duration of abnormal behaviours related to total tacking‐up time was 25–75% in 51% of horses. There was a positive relationship between the sum of abnormal behaviours and the duration of abnormal behaviours (P = 0.0001). Repeatedly chomping on the bit occurred most frequently during bridling (67%). Ears back (57–65%) and an intense stare (54–62%) were similar in all phases. Fidgeting was more common during saddle placement (32%) and girthing (21%), than bridling (9%). Tail swishing was more frequent during saddle placement (20%) and girthing (34%), than bridling (10%). Turning the head to the girth was only seen during saddle placement and girthing (11 and 40%, respectively), in addition to attempting to bite (5 and 15%, respectively) and rubbing the nose (8 and 21%, respectively). The median sum of abnormal behaviours during mounting was 1/30 (IQR 1.3; range 0.12). Main limitations: Absence of many nonlame horses with correctly fitting tack. Conclusion: Abnormal behaviour during tacking‐up and mounting was common. [ABSTRACT FROM AUTHOR]

Quinary GaInAsSbBi is grown by molecular beam epitaxy, and the alloy is demonstrated with a bandgap energy of 291 meV (λcutoff ∼ 4.3 μm) and a minority carrier lifetime of 0.34 μs at 120 K. The GaInAsSbBi epilayer is grown to a thickness of 1 μm at 400 °C and lattice-matched to the GaSb substrate with a Bi mole fraction of 0.13% measured by Rutherford backscattering spectroscopy. Steady-state and time-resolved photoluminescence measurements are performed to gauge the comparative bandgaps and optical quality of GaInAsSbBi as well as InAsSbBi and GaInAsSb reference samples. A recombination rate analysis is performed on the low-injection temperature-dependent minority carrier lifetime to extract the Shockley–Read–Hall defect level and intrinsic doping concentration of the GaInAsSbBi. [ABSTRACT FROM AUTHOR]

The Mesolithic-Neolithic transition is a classic topic of archaeological discussion, and the East Adriatic is of particular interest as a gateway region for agriculture entering Europe from the Near East. Neolithisation along the East Adriatic coast has been characterised as a two-wave process of leap-frog demographic replacement along the Dalmatian coast, followed by a longer process of acculturation further inland. Research on this transition primarily addresses the arrival of Neolithic technology and domesticates, but the view from 'traditionally Mesolithic' activities can provide an alternative perspective. This pilot study highlights one such practice, identifying changes in the seasonality of shellfish gathering over the Neolithic transition using material from Vela Spila, Korčula (Croatia). Specimens of the gastropod Phorcus turbinatus from across this transition were assessed using oxygen isotope analysis. Results showed a focus on summer and autumn collection during the Mesolithic, which then shifted to autumn and winter in the Neolithic. These results indicate differences in shellfish gathering and exploitation across the Neolithic transition, and implications for the demographic transition and human-environment interactions are discussed. Shellfishing in the East Adriatic is identified as an area of Neolithisation rather than Mesolithic continuity. [ABSTRACT FROM AUTHOR]

Characterization of semiconductor nanoparticle (NP) morphologies is demonstrated using the Warren–Averbach (WA) method of powder X-ray diffraction. WA analysis provides crystallographic direction-dependent size distributions. It is as information-rich as electron microscopy, with the benefit of being applicable to a whole specimen. Lead chalcogenide NPs are characterized to demonstrate the analysis. The WA method reflects the homogeneity of quantum dots, differentiates the spheres and cubes from anisotropic morphologies, and distinguishes nanowires via the oriented attachment mechanism versus the solution–liquid–solid method. [ABSTRACT FROM AUTHOR]

Random telegraph noise (RTN) is a type of low-frequency noise that degrades the sensitivity of focal plane arrays (FPAs) and other electronics. Careful analysis of RTN provides information about the material defects generating this noise and ultimately may lead to a solution to eliminate this noise source from the optoelectronic imaging system. The focus of this effort is the definition and demonstration of a simple histogram-based detection algorithm, which evaluates the shape of the pixel output histogram in order to detect RTN pixels and extract the energy levels of the defects. The algorithm sensitivity and precision statistics are benchmarked as a function of the detection threshold. Applying the algorithm to a $1280\times1024$ infrared FPA irradiated with $3.2\times 10^{11}$ protons/cm2(63 MeV) shows a maximum 84% increase in the number of pixels exhibiting RTN from preradiation to post-300 K anneal. The distribution of preradiation trap energies shows clusters at 13 meV above the Fermi level and 14 and 44 meV below the Fermi level. The radiation-induced defects, however, exhibit a different energy distribution with an increased concentration at the Fermi level, suggesting different energy distributions for the traps created during the manufacturing process compared to those created by proton radiation. [ABSTRACT FROM AUTHOR]

The risks of environmental exposures of quantum dot (QD) nanoparticles are increasing, but these risks are difficult to assess because fundamental questions remain about factors affecting the mobility of QDs. The objective of this study is to help address this shortcoming by evaluating the physico-chemical mechanisms controlling the transport and retention of CdSe/ZnS QDs under various environmental conditions. The approach was to run a series of laboratory-scale column experiments where QDs were transported through saturated porous media with different pH values and concentrations of citrate and Suwannee River natural organic matter (SRNOM). Numerical simulations were then conducted and compared with the laboratory data in order to evaluate parameters controlling transport. QD suspensions were injected into the column in an upward direction and ICP-MS used to analyze Cd2+ concentrations (C) in column effluent and sand porous media samples. The increase in the background solution pH values enhanced the QD transport and decreased the QD retention. QD transport recovery percentages obtained from the column effluent samples were 2.6%, 83.2%, 101.7%, 96.5%, and 98.9%, at pH levels of 1.5, 3.5, 5, 7, and 9, respectively. The effects of citrate and SRNOM on the transport and retention of QDs were pH dependent as reflected in the influence of the electrostatic and steric interactions between QDs and sand surfaces. QDs were mobile under unfavorable deposition conditions at environmentally relevant pHs (i.e., 5, 7, and 9). Under favorable pH conditions for deposition (i.e., 1.5), QDs were completely retained within the porous media. The retention profiles of QDs showed a non-exponential decay with distance to the inlet, attributed to multiple deposition rates caused by the QD particles and surface heterogeneities of the quartz silica sand. Results of the diameter ratios of QDs to the median sand grains, in suspensions of DI water at pH 1.5, of citrate at pH 1.5, and of citrate at pH 3.5 indicate straining as the dominating mechanism for QD retention in porous media. The blocking effect and straining were significant under favorable deposition conditions and the detachment effect was non-negligible under unfavorable deposition conditions. Physico-chemical attachment and straining are the governing mechanisms that control the retention of QDs. Overall, experimental results indicate that aggregation, deposition, straining, blocking, and DLVO-type interactions affect the advective transport and retention of QDs in saturated porous media. The simulations were conducted using models that include terms describing attachment, detachment, and straining terms—model 1: M1-attachment, model 2: M2-attachment and detachment, model 3: M3-straining, and model 4: M4-attachment, detachment, and straining. The results from simulations with M2-attachment and detachment and M4-attachment, detachment, and straining matched best the observed breakthrough curves, but all four models inadequately described the retention profiles. Our findings demonstrate that QDs are mobile in porous media under a wide range of physico-chemical conditions representative of the natural environment. The mobility behavior of QDs in porous media indicated the potential risk of soil and groundwater contamination. [ABSTRACT FROM AUTHOR]

We introduce a setup to measure high-resolution inelastic x-ray scattering at the High Energy Density scientific instrument at the European X-Ray Free-Electron Laser (XFEL). The setup uses the Si (533) reflection in a channel-cut monochromator and three spherical diced analyzer crystals in near-backscattering geometry to reach a high spectral resolution. An energy resolution of 44 meV is demonstrated for the experimental setup, close to the theoretically achievable minimum resolution. The analyzer crystals and detector are mounted on a curved-rail system, allowing quick and reliable changes in scattering angle without breaking vacuum. The entire setup is designed for operation at 10 Hz, the same repetition rate as the high-power lasers available at the instrument and the fundamental repetition rate of the European XFEL. Among other measurements, it is envisioned that this setup will allow studies of the dynamics of highly transient laser generated states of matter. [ABSTRACT FROM AUTHOR]

High-energy and high-intensity lasers are essential for pushing the boundaries of science. Their development has allowed leaps forward in basic research areas, including laser–plasma interaction, high-energy density science, metrology, biology and medical technology. The Helmholtz International Beamline for Extreme Fields user consortium contributes and operates two high-peak-power optical lasers using the high energy density instrument at the European X-ray free electron laser (EuXFEL) facility. These lasers will be used to generate transient extreme states of density and temperature to be probed by the X-ray beam. This paper introduces the ReLaX laser, a short-pulse high-intensity Ti:Sa laser system, and discusses its characteristics as available for user experiments. It will also present the first experimental commissioning results validating its successful integration into the EuXFEL infrastructure and viability as a relativistic-intensity laser driver. [ABSTRACT FROM AUTHOR]

Small angle x-ray scattering (SAXS) is a well established technique to detect nanometer scale structures in matter. In a typical setup, this diagnostic uses a detector with a direct line of sight to the scattering target. However, in the harsh environment of high intensity laser interaction, intense secondary radiation and high-energy particles are generated. Such a setup would therefore suffer a significant increase of noise due to this background, which could eventually prevent such measurements. In this paper, we present a novel tool consisting of a mosaic graphite crystal that works as a mirror for the SAXS signal and allows us to position the detector behind appropriate shielding. This paper studies the performance of this mirror both by experiment at the European XFEL (X-Ray Free-Electron Laser Facility) laboratory and by simulations. [ABSTRACT FROM AUTHOR]

High-energy (>40 MeV) protons are commonly used to characterize radiation tolerance of space electronics against damage caused by energy transfer to the nuclei and electrons of semiconductor materials while in orbit. While practically useful, these experiments are unrepresentative in terms of particle type and energy spectra, which results in disproportionate amounts of displacement damage and total ionizing dose. We compare these damages to those realized by bulk semiconductors used in optoelectronics in common low, medium, and high Earth orbits by calculating the duration in orbit required to achieve equivalent nuclear and electronic energy deposition. We conduct this analysis as a function of test proton energy, material, material thickness, and shielding thickness. The ratio of nuclear to electronic orbit duration, a value which would approach unity in an ideal radiation tolerance test, is found to exceed unity in the majority of cases but approaches unity as Al shielding increases. This study provides a connection between damage produced in terrestrial accelerator-based characterizations and orbit irradiation in terms of both damage modes which can cause optoelectronic components to fail: displacement damage and total ionizing dose. [ABSTRACT FROM AUTHOR]

Advancing the understanding of stability behavior and aggregation mechanisms of quantum dot (QD) nanoparticles in natural systems is fundamental to elucidate their fate and transport, bioavailability, environmental toxicity, and subsequent risks to environmental and public health. This study investigates the aggregation kinetics and colloidal stability of QDs as a function of pH and organic ligands—acetate, oxalate, and citrate. Results indicated an influence of solution chemistry upon both the aggregation kinetics and colloidal stability of QDs. The zeta potential of QDs, with a point of zero charge (pHPZC) between pH 1.5 and 3.5, decreased (from positive to negative) with increasing solution pH. The diameter of QD aggregates was ~500 nm in the region of pHPZC and decreased with pH when pH > pHPZC to 40–50 nm. Organic ligands enhanced the negative zeta potentials of QDs at pH = 1.5 and pH = 3.5. The impact of ligands on the levels and rates of aggregation was pH dependent; furthermore, the presence of ligands increased the diameters of all QD nanoaggregates at pH 3.5 (e.g., 817 nm for 0.001 M citrate). QDs and organic ligand-QD nanoparticle complexes remained stable across pH values 5–9. In terms of environmental and toxicological risk assessments, results revealed that QDs and organic ligand-QD nanoparticle complexes remain stable across a significant range of pH values (5–9), indicating that this stability behavior could enhance the mobility, transport, and residence time of QDs in terrestrial and aqueous environments, and facilitate the bioavailability of QDs, therefore augmenting the adverse effects of QDs in the environment. [ABSTRACT FROM AUTHOR]

Time-resolved photoluminescence measurements are reported for InAsSbBi alloys grown by molecular beam epitaxy with Bi mole fractions ranging from 0 to 0.8%, yielding minority carrier lifetimes on the order of hundreds of nanoseconds. The minority carrier lifetimes extracted from the time-resolved photoluminescence measurements are comparable to those of lattice-matched InAsSb grown at the same respective temperatures. Nomarski imaging shows that smooth, droplet-free surface morphologies are obtained in 1 μm thick InAsSbBi epilayers grown at temperatures between 360 and 380 °C. The alloy composition-dependent bandgap energies for the InAsSbBi samples are determined from temperature-dependent steady-state photoluminescence measurements and compared with the tetragonal distortion measured by x-ray diffraction to determine the Sb and Bi mole fractions of each sample. The minority carrier lifetime and the achievable extension of the InAsSb(Bi) cut-off wavelength are analyzed as functions of alloy composition and compared with the performance of InAsSb layers with similar growth parameters. [ABSTRACT FROM AUTHOR]

Anisotropic carrier transport properties of unintentionally doped InAs/InAs0.65Sb0.35 type-II strain-balanced superlattice material are evaluated using temperature- and field-dependent magnetotransport measurements performed in the vertical direction on a substrate-removed metal-semiconductor-metal device structure. To best isolate the measured transport to the superlattice, device fabrication entails flip-chip bonding and backside device processing to remove the substrate material and deposit contact metal directly to the bottom of an etched mesa. High-resolution mobility spectrum analysis is used to calculate the conductance contribution and corrected mixed vertical-lateral mobility of the two carrier species present. Combining the latter with lateral mobility results from in-plane magnetotransport measurements on identical superlattice material allows for the calculation of the true vertical majority electron and minority hole mobilities; amplitudes of 4.7 × 10 3 cm2/V s and 1.60 cm2/V s are determined at 77 K, respectively. The temperature-dependent results show that vertical hole mobility rapidly decreases with decreasing temperature due to trap-induced localization and then hopping transport, whereas vertical electron mobility appears phonon scattering-limited at high temperature, giving way to interface roughness scattering at low temperatures, analogous to the lateral electron mobility but with a lower overall magnitude. [ABSTRACT FROM AUTHOR]

The Sand Mountain and Lookout Mountain Plateaus in northeastern Alabama have been established as a regional relative maximum in tornadogenesis reports within the southeastern United States. Investigation of long-term surface datasets has revealed (i) stronger and more backed winds atop Sand Mountain than over the Tennessee Valley, and (ii) measured cloud-base heights are lower to the surface atop Sand Mountain than over the Tennessee Valley. These observations suggest that low-level wind shear and lifting condensation level (LCL) height changes may lead to conditions more favorable for tornadogenesis atop the plateaus than over the Tennessee Valley. However, prior to fall 2016, no intensive observations had been made to further investigate low-level flow or thermodynamic changes in the topography of northeastern Alabama. This paper provides detailed analysis of observations gathered during VORTEX-SE field campaign cases from fall 2016 through spring 2019. These observations indicate that downslope winds form along the northwest edge of Sand Mountain in at least some severe storm environments in northeastern Alabama. Wind profiles gathered across northeastern Alabama indicate that low-level helicity changes can be substantial over small distances across different areas of the topographic system. LCL height changes often scale to changes in land elevation, which can be on the order of 200–300 m across northeastern Alabama. [ABSTRACT FROM AUTHOR]

Velocity-map ion imaging has been applied to the photodissociation of NO2 via the first absorption band at 308 nm using (2+1) resonantly enhanced multiphoton ionization detection of the atomic O(3PJ) products. The resulting ion images have been analyzed to provide information about the speed distribution of the O(3PJ) products, the translational anisotropy, and the electronic angular momentum alignment. The atomic speed distributions were used to provide information about the internal quantum-state distribution in the NO coproducts. The data were found to be consistent with an inverted NO vibrational quantum-state distribution, and thereby point to a dynamical, as opposed to a statistical dissociation mechanism subsequent to photodissociation at 308 nm. Surprisingly, at this wavelength the O-atom electronic angular momentum alignment was found to be small. Probe-only ion images obtained under a variety of molecular-beam backing-pressure conditions, and corresponding to O atoms generated in the photodissociation of either the monomer, NO2, or the dimer, N2O4, at 226 nm, are also reported. For the monomer, where 226 nm corresponds to excitation into the second absorption band, the kinetic-energy release distributions are also found to indicate a strong population inversion in the NO cofragment, and are shown to be remarkably similar to those previously observed in the wavelength range of 193–248 nm. Mechanistic implications of this result are discussed. At 226 nm it has also been possible to observe directly O atoms from the photodissociation of the dimer. The O-atom velocity distribution has been analyzed to provide information about its production mechanism. [ABSTRACT FROM AUTHOR]

The electronic structure of conjugated polymer films is of current interest due to the wide range of potential applications for such materials in optoelectronic devices. A central outstanding issue is the significance of interchain electronic species in films of these materials. In this paper, we investigate the nature of interchain species in films of poly[2-methoxy-5-(2′-ethylhexyloxy)-l,4-phenylene vinylene] (MEH-PPV) both before and after thermal annealing. Our investigation employs a combination of third harmonic generation (THG) and near-field scanning optical microscopy to measure the wavelength and spatial dependence of the THG efficiency. These chemically selective imaging measurements reveal new, low-energy absorption features in nanometer-scale spatially distinct regions of annealed films that are only infrequently observed prior to annealing. This suggests that the polymer strands in annealed MEH-PPV films pack together closely enough that significant ground-state wave function overlap can occur: thermal annealing creates nanoscopic aggregation domains. THG polarization studies indicate that polymer chain segments in these domains have a preferred orientational alignment. The spatial correlation of these aligned nanoscopic regions within the annealed films suggests that they form via a nucleation and growth type mechanism. In combination with previous work, these data support the idea that the nature and spatial distribution of interchain interactions in conjugated polymer films are complex; conjugated polymer films likely contain an inhomogeneous spatial distribution of both ground- and excited-state interchain species. [ABSTRACT FROM AUTHOR]

Critical satellite-based electronics can fail due to irradiation with Van Allen belt trapped protons. While nuclear-reaction-induced transmutation damage is typically ignored, a recent study raised the question of its potential importance in explaining anomalous trends in III–V nBn device operation. To investigate this postulation and to generally quantify the importance of transmutation in semiconductors for space applications, transmutation rates occurring in eight prominent semiconductor systems irradiated with typical device qualification protons of 63 MeV and operating in LEO, MEO, and GEO orbits are examined computationally employing FISPACT-II (validated through experiment and GEANT4 simulations). It is found that the transmutation realized in the III–V nBn device is three orders of magnitude less than would have been required to bring experiment into agreement with theory and that, furthermore, the total transmuted elemental concentrations never exceed 1010 cm−3 in any semiconductor at the end of 10 years of operation in any orbit considered. Thus, the effect of nuclear transmutation can be safely neglected in predicting modern device operation in orbit. [ABSTRACT FROM AUTHOR]

Many high-power radio frequency communication and navigation systems utilize multicarrier systems. Testing and analyzing such systems for multipactor breakdown have no universal approach, and current practices range in their degree of conservatism. A common approach involves considering the number of signal crossings above the single carrier breakdown threshold. Previous experimental work [Hubble et al., Proceedings of the 9th International Workshop on Multipactor, Corona, and Passive Intermodulation, Noordwijk, The Netherlands (April 2017)] evaluated multicarrier breakdown in two-tone systems and determined a relationship between carrier spacing and required signal crossings to achieve breakdown. This work builds upon the previous effort to include broader carrier spacing and additional tones, as well as the use of innovative center-conductor diagnostics to measure real-time electron population growth and decay. [ABSTRACT FROM AUTHOR]

We present measurements of the plasmon shift in shock-compressed matter as a function of momentum transfer beyond the Fermi wavevector using an X-ray Free Electron Laser. We eliminate the elastically scattered signal retaining only the inelastic plasmon signal. Our plasmon dispersion agrees with both the random phase approximation (RPA) and static Local Field Corrections (sLFC) for an electron gas at both zero and finite temperature. Further, we find the inclusion of electron-ion collisions through the Born-Mermin Approximation (BMA) to have no effect. Whilst we cannot distinguish between RPA and sLFC within our error bars, our data suggest that dynamic effects should be included for LFC and provide a route forward for higher resolution future measurements. [ABSTRACT FROM AUTHOR]

Abstract: Understanding the degree of intraspecific variation within and among populations is a key aspect of predicting the capacity of a species to respond to anthropogenic disturbances. However, intraspecific variation is usually assessed at either limited temporal, but broad spatial scales or vice versa, which can make assessing changes in response to long‐term disturbances challenging. We evaluated the relationship between the longitudinal gradient of changing flow regimes and land use/land cover patterns since 1980 and morphological variation of Guadalupe Bass Micropterus treculii throughout the Colorado River Basin of central Texas. The Colorado River Basin in Texas has experienced major alterations to the hydrologic regime due to changing land‐ and water‐use patterns. Historical collections of Guadalupe Bass prior to rapid human‐induced change present the unique opportunity to study the response of populations to varying environmental conditions through space and time. Morphological differentiation of Guadalupe Bass associated with temporal changes in flow regimes and land use/land cover patterns suggests that they are exhibiting intraspecific trait variability, with contemporary individuals showing increased body depth, in response to environmental alteration through time (specifically related to an increase in herbaceous land cover, maximum flows, and the number of low pulses and high pulses). Additionally, individuals from tributaries with increased hydrologic alteration associated with urbanization or agricultural withdrawals tended to have a greater distance between the anal and caudal fin. These results reveal trait variation that may help to buffer populations under conditions of increased urbanization and sprawl, human population growth, and climate risk, all of which impose novel selective pressures, especially on endemic species like Guadalupe Bass. Our results contribute an understanding of the adaptability and capacity of an endemic population to respond to expected future changes based on demographic or climatic projection. [ABSTRACT FROM AUTHOR]

Criterion data for total energy expenditure (TEE) in elite rugby are lacking, which prediction equations may not reflect accurately. This study quantified TEE of 27 elite male rugby league (RL) and rugby union (RU) players (U16, U20, U24 age groups) during a 14-day in-season period using doubly labelled water (DLW). Measured TEE was also compared to estimated, using prediction equations. Resting metabolic rate (RMR) was measured using indirect calorimetry, and physical activity level (PAL) estimated (TEE:RMR). Differences in measured TEE were unclear by code and age (RL 4369 ± 979; RU 4365 ± 1122; U16, 4010 ± 744; U20, 4414 ± 688; U24, 4761 ± 1523 Kcal day- 1). Differences in PAL (overall mean 2.0 ± 0.4) were unclear. Very likely differences were observed in RMR by code (RL 2366 ± 296; RU 2123 ± 269 Kcal day- 1). Differences in relative RMR between U20 and U24 were very likely (U16, 27 ± 4; U20, 23 ± 3; U24, 26 ± 5 Kcal kg- 1 day- 1). Differences were observed between measured and estimated TEE, using Schofield, Cunningham and Harris-Benedict equations for U16 (187 ± 614, unclear; - 489 ± 564, likely and - 90 ± 579, unclear Kcal day- 1), U20 (- 449 ± 698, likely; - 785 ± 650, very likely and - 452 ± 684, likely Kcal day- 1) and U24 players (- 428 ± 1292; - 605 ± 1493 and - 461 ± 1314 Kcal day- 1, all unclear). Rugby players have high TEE, which should be acknowledged. Large inter-player variability in TEE was observed demonstrating heterogeneity within groups, thus published equations may not appropriately estimate TEE. [ABSTRACT FROM AUTHOR]