Specimen collection is essential for modern science.

Natural history museums are vital repositories of specimens, samples and data that inform about the natural world; this Formal Comment revisits a Perspective that advocated for the adoption of compassionate collection practices, querying whether it will ever be possible to completely do away with whole animal specimen collection.

Complex PTSD symptoms predict positive symptoms of psychosis in the flow of daily life.

BACKGROUND: Post-traumatic stress disorder (PTSD) has been shown to predict psychotic symptomology. However, few studies have examined the relative contribution of PTSD compared to broader post-traumatic sequelae in maintaining psychosis. Complex PTSD (cPTSD), operationalized using ICD-11 criteria, includes core PTSD (intrusions, avoidance, hyperarousal) as well as additional "disturbances of self-organisation" (DSO; emotional dysregulation, interpersonal difficulties, negative self-concept) symptoms, more likely to be associated with complex trauma histories. It was hypothesized that DSOs would be associated with positive psychotic symptoms (paranoia, voices, and visions) in daily life, over and above core PTSD symptoms. METHODS: This study (N = 153) employed a baseline subsample of the Study of Trauma And Recovery (STAR), a clinical sample of participants with comorbid post-traumatic stress and psychosis symptoms. Core PTSD, DSO and psychosis symptoms were assessed up to 10 times per day at quasi-random intervals over six consecutive days using Experience Sampling Methodology. RESULTS: DSOs within the preceding 90 min predicted paranoia, voices, and visions at subsequent moments. These relationships persisted when controlling for core PTSD symptoms within this timeframe, which were themselves significant. The associations between DSOs and paranoia but not voices or visions, were significantly stronger than those between psychosis and core PTSD symptoms. CONCLUSIONS: Consistent with an affective pathway to psychosis, the findings suggest that DSOs may be more important than core PTSD symptoms in maintaining psychotic experiences in daily life among people with comorbid psychosis and cPTSD, and indicate the potential importance of addressing broad post-traumatic sequelae in trauma-focused psychosis interventions.

Genetic erosion in an endangered desert fish during a megadrought despite long-term supportive breeding.

Human water use combined with a recent megadrought have reduced river and stream flow through the southwest United States and led to periodic drying of formerly perennial river segments. Reductions in snowmelt runoff and increased extent of drying collectively threaten short-lived, obligate aquatic species, including the endangered Rio Grande silvery minnow (Hybognathus amarus). This species is subject to boom-and-bust population dynamics, under which large fluctuations in abundance are expected to lower estimates of effective population size and erode genetic diversity over time. Rates of diversity loss are also affected by additions of hatchery-origin fish used to supplement the wild population. We used demographic and genetic data from wild and hatchery individuals to examine the relationship of genetic diversity and effective population size to abundance over the last two decades. Genetic diversity was low during the early 2000s, but diversity and demographic metrics stabilized after the hatchery program was initiated and environmental conditions improved. Yet, from 2017 onward, allelic diversity declined (Cohen's d = 1.34) and remained low despite hatchery stocking and brief wild population recovery. Across the time series, single-sample estimates of effective population size based on linkage disequilibrium (LD Ne ) were positively associated (r = 0.53) with wild abundance and total abundance, but as the proportion of hatchery-origin spawners increased, LD Ne declined (r = -0.55). Megadrought limited wild spawner abundance and precluded refreshment of hatchery brood stocks with wild fish; hence, we predict a riverine population increasingly dominated by hatchery-origin individuals and accelerated loss of genetic diversity despite supplementation. We recommend an adaptive and accelerated management plan that integrates river flow management and hatchery operations to slow the pace of genetic diversity loss exacerbated by megadrought.

El uso humano del agua, combinado con una megasequía reciente, ha reducido el flujo de los ríos y arroyos en el suroeste de los Estados Unidos y ha provocado la seca periódica de segmentos de ríos que antes eran perennes. Las reducciones en la escorrentía del deshielo y el aumento de la sequía amenazan colectivamente a especies obligatoriamente acuáticas de vida corta, incluyendo la amenazada carpa chamizal (Hybognathus amarus). Esta especie está sujeta a una dinámica poblacional de explosión y colapso, bajo la cual se espera que grandes fluctuaciones en la abundancia reduzcan las estimaciones del tamaño efectivo de la población y erosionen la diversidad genética con el tiempo. Las tasas de pérdida de la diversidad también se ven afectadas por la adición de peces procedentes de criaderos usados para suplementar la población silvestre. Utilizamos datos demográficos y genéticos de individuos silvestres y de criaderos para examinar la relación entre la diversidad genética y el tamaño efectivo de la población con la abundancia durante las últimas dos décadas. La diversidad genética fue baja a principios de los 2000, pero las métricas de diversidad y demografía estabilizaron después de que se inició el programa de criadero y mejoraron las condiciones ambientales. Sin embargo, a partir de 2017, la diversidad alélica disminuyó (d de Cohen = 1,34) y se mantuvo baja a pesar de la suplementación con individuos de criaderos y la breve recuperación de la población silvestre. A lo largo del tiempo, las estimativas de muestras individuales del tamaño efectivo de la población basados en el desequilibrio de ligamiento (LD Ne) estaban asociadas positivamente (r = 0,53) con la abundancia silvestre y la abundancia total, pero a medida que la proporción de desovadores originados en criaderos aumentó, el LD Ne disminuyó (r = -0,55). La megasequía limitó la abundancia de desovadores silvestres e impidió el reabastecimiento de las poblaciones en cautiverio con peces silvestres; por lo tanto, predecimos una población ribereña cada vez más dominada por individuos procedentes de criaderos y una pérdida acelerada de diversidad genética a pesar de la suplementación. Recomendamos un plan de gestión adaptativo y acelerado que integre la gestión del caudal del río y las operaciones de criaderos para frenar el ritmo de pérdida de diversidad genética exacerbada por la megasequía.

Non-clinical hallucinations and mental imagery across sensory modalities.

INTRODUCTION: Vivid mental imagery has been proposed to increase the likelihood of experiencing hallucinations. Typically, studies have employed a modality general approach to mental imagery which compares imagery across multiple domains (e.g., visual, auditory and tactile) to hallucinations in multiple senses. However, modality specific imagery may be a better predictor of hallucinations in the same domain. The study examined the contribution of imagery to hallucinations in a non-clinical sample and specifically whether imagery best predicted hallucinations at a modality general or modality specific level. METHODS: In study one, modality general and modality specific accounts of the imagery-hallucination relationship were contrasted through application of self-report measures in a sample of 434 students. Study two used a subsample (n = 103) to extend exploration of the imagery-hallucinations relationship using a performance-based imagery task. RESULTS: A small to moderate modality general relationship was observed between self-report imagery and hallucination proneness. There was only evidence of a modality specific relationship in the tactile domain. Performance-based imagery measures were unrelated to hallucinations and self-report imagery. CONCLUSIONS: Mental imagery may act as a modality general process increasing hallucination proneness. The observed distinction between self-report and performance-based imagery highlights the difficulty of accurately measuring internal processes.

Hummingbird blood traits track oxygen availability across space and time.

Predictable trait variation across environments suggests shared adaptive responses via repeated genetic evolution, phenotypic plasticity or both. Matching of trait-environment associations at phylogenetic and individual scales implies consistency between these processes. Alternatively, mismatch implies that evolutionary divergence has changed the rules of trait-environment covariation. Here we tested whether species adaptation alters elevational variation in blood traits. We measured blood for 1217 Andean hummingbirds of 77 species across a 4600-m elevational gradient. Unexpectedly, elevational variation in haemoglobin concentration ([Hb]) was scale independent, suggesting that physics of gas exchange, rather than species differences, determines responses to changing oxygen pressure. However, mechanisms of [Hb] adjustment did show signals of species adaptation: Species at either low or high elevations adjusted cell size, whereas species at mid-elevations adjusted cell number. This elevational variation in red blood cell number versus size suggests that genetic adaptation to high altitude has changed how these traits respond to shifts in oxygen availability.

The Oxford Agoraphobic Avoidance Scale.

BACKGROUND: Agoraphobic avoidance of everyday situations is a common feature in many mental health disorders. Avoidance can be due to a variety of fears, including concerns about negative social evaluation, panicking, and harm from others. The result is inactivity and isolation. Behavioural avoidance tasks (BATs) provide an objective assessment of avoidance and in situ anxiety but are challenging to administer and lack standardisation. Our aim was to draw on the principles of BATs to develop a self-report measure of agoraphobia symptoms. METHOD: The scale was developed with 194 patients with agoraphobia in the context of psychosis, 427 individuals in the general population with high levels of agoraphobia, and 1094 individuals with low levels of agoraphobia. Factor analysis, item response theory, and receiver operating characteristic analyses were used. Validity was assessed against a BAT, actigraphy data, and an existing agoraphobia measure. Test-retest reliability was assessed with 264 participants. RESULTS: An eight-item questionnaire with avoidance and distress response scales was developed. The avoidance and distress scales each had an excellent model fit and reliably assessed agoraphobic symptoms across the severity spectrum. All items were highly discriminative (avoidance: a = 1.24-5.43; distress: a = 1.60-5.48), indicating that small increases in agoraphobic symptoms led to a high probability of item endorsement. The scale demonstrated good internal reliability, test-retest reliability, and validity. CONCLUSIONS: The Oxford Agoraphobic Avoidance Scale has excellent psychometric properties. Clinical cut-offs and score ranges are provided. This precise assessment tool may help focus attention on the clinically important problem of agoraphobic avoidance.

Virtual reality (VR) therapy for patients with psychosis: satisfaction and side effects.

BACKGROUND: Automated virtual reality therapies are being developed to increase access to psychological interventions. We assessed the experience with one such therapy of patients diagnosed with psychosis, including satisfaction, side effects, and positive experiences of access to the technology. We tested whether side effects affected therapy. METHODS: In a clinical trial 122 patients diagnosed with psychosis completed baseline measures of psychiatric symptoms, received gameChange VR therapy, and then completed a satisfaction questionnaire, the Oxford-VR Side Effects Checklist, and outcome measures. RESULTS: 79 (65.8%) patients were very satisfied with VR therapy, 37 (30.8%) were mostly satisfied, 3 (2.5%) were indifferent/mildly dissatisfied, and 1 (0.8%) person was quite dissatisfied. The most common side effects were: difficulties concentrating because of thinking about what might be happening in the room (n = 17, 14.2%); lasting headache (n = 10, 8.3%); and the headset causing feelings of panic (n = 9, 7.4%). Side effects formed three factors: difficulties concentrating when wearing a headset, feelings of panic using VR, and worries following VR. The occurrence of side effects was not associated with number of VR sessions, therapy outcomes, or psychiatric symptoms. Difficulties concentrating in VR were associated with slightly lower satisfaction. VR therapy provision and engagement made patients feel: proud (n = 99, 81.8%); valued (n = 97, 80.2%); and optimistic (n = 96, 79.3%). CONCLUSIONS: Patients with psychosis were generally very positive towards the VR therapy, valued having the opportunity to try the technology, and experienced few adverse effects. Side effects did not significantly impact VR therapy. Patient experience of VR is likely to facilitate widespread adoption.

Sideways maneuvers enable narrow aperture negotiation by free-flying hummingbirds.

Many birds routinely fly fast through dense vegetation characterized by variably sized structures and voids. Successfully negotiating these cluttered environments requires maneuvering through narrow constrictions between obstacles. We show that Anna's hummingbirds (Calypte anna) can negotiate apertures less than one wingspan in diameter using a novel sideways maneuver that incorporates continuous, bilaterally asymmetric wing motions. Crucially, this maneuver allows hummingbirds to continue flapping as they negotiate the constriction. Even smaller openings are negotiated via a faster ballistic trajectory characterized by tucked and thus non-flapping wings, which reduces force production and increases descent rate relative to the asymmetric technique. Hummingbirds progressively shift to the swept method as they perform hundreds of consecutive transits, suggesting increased locomotor performance with task familiarity. Initial use of the slower asymmetric transit technique may allow birds to better assess upcoming obstacles and voids, thereby reducing the likelihood of subsequent collisions. Repeated disruptions of normal wing kinematics as birds negotiate tight apertures may determine the limits of flight performance in structurally complex environments. These strategies for aperture transit and associated flight trajectories can inform designs and algorithms for small aerial vehicles flying within cluttered environments.

Coping with captivity: takeoff speed and load-lifting capacity are unaffected by substantial changes in body condition for a passerine bird.

Captivity presumably challenges the physiological equilibrium of birds and thus influences flight ability. However, the extent to which captive birds exhibit altered features underpinning maximum flight performance remains largely unknown. Here, we studied changes in physiological condition and load-lifting performance in the Eurasian tree sparrow (Passer montanus) over 15, 30 and 45 days of captivity. Sparrows showed body mass constancy over time but also an increased hematocrit at 15 days of captivity; both relative pectoralis mass and pectoralis fat content increased at 30 days. However, maximum takeoff speed and maximum lifted load remained largely unchanged until 45 days of captivity. Wingbeat frequency was independent of captivity duration and loading condition, whereas body angle and stroke plane angle varied only with maximum loading and not with duration of captivity. Overall, these results suggest that captive birds can maintain maximum flight performance when experiencing dramatic changes in both internal milieu and external environment.

Aerial maneuvering by plethodontid salamanders spanning an arboreality gradient.

Wandering salamanders (Aneides vagrans) inhabit the crowns of the world's tallest trees, taking refuge in epiphytic fern mats within these complex arboreal environments. These salamanders readily jump from the canopy when disturbed and maintain stable postures while falling via fine adjustments of the limbs and tail in lieu of dedicated aerodynamic control surfaces, thus reliably carrying out non-vertical descent. Here, we examined the aerial behavior and performance of A. vagrans and three other species of plethodontid salamander across a habitat gradient of arboreality by recording salamanders falling from short heights and moving within the jet of a vertical wind tunnel. Kinematic performance of aerial behavior in plethodontid salamanders was correlated with a gradient of arboreal habitats; moreover, salamanders from arboreal niches were more effective in slowing and redirecting descent compared with other salamanders. Aneides vagrans and the closely related Aneides lugubris consistently engaged in parachuting and gliding when falling; their trajectories were very steep, but were sufficiently angled to enable contact with either the home trunk or nearby branches during falls or jumps from great heights. Aerial maneuvering in arboreal salamanders is similar to that seen in other vertebrates capable of non-vertical and controlled descent, suggesting that the long limbs and active tail of these arboreal plethodontids (often cited as adaptations for climbing) may also contribute to parachuting and gliding when falling from trees. These aerial behaviors within the redwood canopy warrant further investigations into other canopy residents that lack conspicuous surfaces for aerodynamic control.

Two-Year Analysis of a New Oral Testosterone Undecanoate (TU) Formulation in Hypogonadal Men: Efficacy, Impact on Psychosexual Function, and Safety.

BACKGROUND: Long-term data evaluating the efficacy and safety of oral testosterone undecanoate (oral TU; JATENZO) in adult hypogonadal men provides important information for healthcare professionals who prescribe testosterone replacement therapy (TRT). AIM: To determine the efficacy and safety of long-term oral TU therapy, including its impact on total testosterone (T) levels and psychosexual functioning. METHODS: Hypogonadal men, between 18 and 75 years old, (mean age 56.2; 87.2% white) who completed a 12-month, open-label, multicenter, randomized, active-controlled trial were given the opportunity to enroll in a 12-month extension study. Among the 129 eligible TU-treated subjects, 86 chose this option, and 69 completed 24 months of uninterrupted oral TU therapy. OUTCOMES: The efficacy of oral TU was documented by measuring total serum T concentrations; sexual function was measured using the Psychosexual Daily Questionnaire (PDQ). For safety, liver function tests, cardiovascular endpoints, and prostate health were measured. RESULTS: Over 2 years, total serum T concentrations for patients treated with oral TU were in the eugonadal range (300-1,000 ng/dL [10-35 nmol/L]; mean ± SD: 617 ± 427 ng/dL [21 ± 15 nmol/L]) and increased significantly from baseline (P < .0001). For sexual function, mean score changes versus baseline for all PDQ domains at all time points were significantly improved (P < .0011 for all). For the sexual activity and sexual desire components, patient scores were consistently greater than validated thresholds for clinically meaningful change. Typical T-induced safety changes were observed, including a 3-6 mm Hg increase in systolic blood pressure (P < .05); a slight increase in hematocrit (P < .0001) that stayed <48% throughout the study; no clinically significant changes in prostate-specific antigen levels; and decreased high-density lipoprotein cholesterol (-9.8 ± 0.9 mg/dL from baseline; P < .0001). There were no clinically significant changes from baseline in liver function tests. CLINICAL IMPLICATIONS: Over 2 years of treatment, this novel oral TU formulation maintained total T concentrations in mideugonadal ranges, with improvements in sexual function and no clinically significant changes in liver function or other safety concerns previously associated with oral TRT. STRENGTHS & LIMITATIONS: These are the first long-term data to evaluate the efficacy and safety of a novel formulation of oral TU; the comparative long-term safety of oral TU would be strengthened by confirmatory studies versus other TRT formulations. CONCLUSION: Oral TU offers a safe and effective long-term treatment option for men with hypogonadism. Honig S, Gittelman M, Kaminetsky J, et al. Two-Year Analysis of a New Oral Testosterone Undecanoate (TU) Formulation in Hypogonadal Men: Efficacy, Impact on Psychosexual Function, and Safety. J Sex Med 2022;19:1750-1758.

Estimating the Economic Value of Automated Virtual Reality Cognitive Therapy for Treating Agoraphobic Avoidance in Patients With Psychosis: Findings From the gameChange Randomized Controlled Clinical Trial.

BACKGROUND: An automated virtual reality cognitive therapy (gameChange) has demonstrated its effectiveness to treat agoraphobia in patients with psychosis, especially for high or severe anxious avoidance. Its economic value to the health care system is not yet established. OBJECTIVE: In this study, we aimed to estimate the potential economic value of gameChange for the UK National Health Service (NHS) and establish the maximum cost-effective price per patient. METHODS: Using data from a randomized controlled trial with 346 patients with psychosis (ISRCTN17308399), we estimated differences in health-related quality of life, health and social care costs, and wider societal costs for patients receiving virtual reality therapy in addition to treatment as usual compared with treatment as usual alone. The maximum cost-effective prices of gameChange were calculated based on UK cost-effectiveness thresholds. The sensitivity of the results to analytical assumptions was tested. RESULTS: Patients allocated to gameChange reported higher quality-adjusted life years (0.008 QALYs, 95% CI -0.010 to 0.026) and lower NHS and social care costs (-£105, 95% CI -£1135 to £924) compared with treatment as usual (£1=US $1.28); however, these differences were not statistically significant. gameChange was estimated to be worth up to £341 per patient from an NHS and social care (NHS and personal social services) perspective or £1967 per patient from a wider societal perspective. In patients with high or severe anxious avoidance, maximum cost-effective prices rose to £877 and £3073 per patient from an NHS and personal social services perspective and societal perspective, respectively. CONCLUSIONS: gameChange is a promising, cost-effective intervention for the UK NHS and is particularly valuable for patients with high or severe anxious avoidance. This presents an opportunity to expand cost-effective psychological treatment coverage for a population with significant health needs. TRIAL REGISTRATION: ISRCTN Registry ISRCTN17308399; https://www.isrctn.com/ISRCTN17308399. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1136/bmjopen-2019-031606.

Understanding agoraphobic avoidance: the development of the Oxford Cognitions and Defences Questionnaire (O-CDQ).

BACKGROUND: Many patients with mental health disorders become increasingly isolated at home due to anxiety about going outside. A cognitive perspective on this difficulty is that threat cognitions lead to the safety-seeking behavioural response of agoraphobic avoidance. AIMS: We sought to develop a brief questionnaire, suitable for research and clinical practice, to assess a wide range of cognitions likely to lead to agoraphobic avoidance. We also included two additional subscales assessing two types of safety-seeking defensive responses: anxious avoidance and within-situation safety behaviours. METHOD: 198 patients with psychosis and agoraphobic avoidance and 1947 non-clinical individuals completed the item pool and measures of agoraphobic avoidance, generalised anxiety, social anxiety, depression and paranoia. Factor analyses were used to derive the Oxford Cognitions and Defences Questionnaire (O-CDQ). RESULTS: The O-CDQ consists of three subscales: threat cognitions (14 items), anxious avoidance (11 items), and within-situation safety behaviours (8 items). Separate confirmatory factor analyses demonstrated a good model fit for all subscales. The cognitions subscale was significantly associated with agoraphobic avoidance (r = .672, p < .001), social anxiety (r = .617, p < .001), generalized anxiety (r = .746, p < .001), depression (r = .619, p < .001) and paranoia (r = .655, p < .001). Additionally, both the O-CDQ avoidance (r = .867, p < .001) and within-situation safety behaviours (r = .757, p < .001) subscales were highly correlated with agoraphobic avoidance. The O-CDQ demonstrated excellent internal consistency (cognitions Cronbach's alpha = .93, avoidance Cronbach's alpha = .94, within-situation Cronbach's alpha = .93) and test-re-test reliability (cognitions ICC = 0.88, avoidance ICC = 0.92, within-situation ICC = 0.89). CONCLUSIONS: The O-CDQ, consisting of three separate scales, has excellent psychometric properties and may prove a helpful tool for understanding agoraphobic avoidance across mental health disorders.

The role of thrifty genes in the origin of alcoholism: A narrative review and hypothesis.

In this narrative review, we present the hypothesis that key mutations in two genes, occurring 15 and 10 million years ago (MYA), were individually and then collectively adaptive for ancestral humans during periods of starvation, but are maladaptive in modern civilization (i.e., "thrifty genes"), with the consequence that these genes not only increase our risk today for obesity, but also for alcoholism. Both mutations occurred when ancestral apes were experiencing loss of fruit availability during periods of profound climate change or environmental upheaval. The silencing of uricase (urate oxidase) activity 15 MYA enhanced survival by increasing the ability for fructose present in dwindling fruit to be stored as fat, a consequence of enhanced uric acid production during fructose metabolism that stimulated lipogenesis and blocked fatty acid oxidation. Likewise, a mutation in class IV alcohol dehydrogenase ~10 MYA resulted in a remarkable 40-fold increase in the capacity to oxidize ethanol (EtOH), which allowed our ancestors to ingest fallen, fermenting fruit. In turn, the EtOH ingested could activate aldose reductase that stimulates the conversion of glucose to fructose, while uric acid produced during EtOH metabolism could further enhance fructose production and metabolism. By aiding survival, these mutations would have allowed our ancestors to generate more fat, primarily from fructose, to survive changing habitats due to the Middle Miocene disruption and also during the late-Miocene aridification of East Africa. Unfortunately, the enhanced ability to metabolize and utilize EtOH may now be acting to increase our risk for alcoholism, which may be yet another consequence of once-adaptive thrifty genes.

Maximum aerodynamic force production by the wandering glider dragonfly (Pantala flavescens, Libellulidae).

Maximum whole-body force production can influence behavioral outcomes for volant taxa, and may also be relevant to aerodynamic optimization in microair vehicles. Here, we describe a new method for measuring maximum force production in free-flying animals, and present associated data for the wandering glider dragonfly. Flight trajectories were repeatedly acquired from pull-up responses by insects dropped in mid-air with submaximal loads attached beneath the center of body mass. Forces were estimated from calculations of the maximum time-averaged acceleration through time, and multiple estimates were obtained per individual so as to statistically facilitate approximation of maximum capacity through use of the Weibull distribution. On a group level, wandering glider dragonflies were here estimated to be capable of producing total aerodynamic force equal to ∼4.3 times their own body weight, a value which significantly exceeds earlier estimates made for load-lifting dragonflies, and also for other volant taxa in sustained vertical load-lifting experiments. Maximum force production varied isometrically with body mass. Falling and recovery flight with submaximal load represents a new context for evaluating limits to force production by flying animals.

Canopy parkour: movement ecology of post-hatch dispersal in a gliding nymphal stick insect, Extatosoma tiaratum.

For flightless arboreal arthropods, moving from the understory into tree canopies is cognitively and energetically challenging because vegetational structures present complex three-dimensional landscapes with substantial gaps. Predation risk and wind-induced perturbations in the canopy may further impede the movement process. In the Australian stick insect Extatosoma tiaratum, first-instar nymphs hatch on the forest floor and disperse toward tree canopies in the daytime. Here, we addressed how their tactic responses to environmental cues and movement strategies are adapted to the canopy environment. Newly hatched nymphs ascend with high endurance, travelling >100 m within 60 min. Navigation toward open canopies is underpinned by negative gravitaxis, positive phototaxis and visual responses to vertically oriented contrast patterns. Nymphal E. tiaratum also use directed jumping to cross gaps, and respond to tactile stimulation and potential threat with a self-dropping reflex, resulting in aerial descent. Post-hatch dispersal in E. tiaratum thus consists of visually mediated displacement both on vegetational structures and in the air; within the latter context, gliding is then an effective mechanism enabling recovery after predator- and perturbation-induced descent. These results further support the importance of a diurnal niche, in addition to the arboreal spatial niche, in the evolution of gliding in wingless arboreal invertebrates.

Low prevalence of patellar tendon abnormality and low incidence of patellar tendinopathy in female collegiate volleyball players.

The prevalence of patellar tendinopathy has been reported to be as high as 50% in elite male volleyball (VB) players; however, the rate of injury in female collegiate VB athletes is unknown. The purpose of this study was to 1) identify the prevalence of ultrasonographic evidence of patellar tendon abnormality at the start of the preseason in female collegiate VB players; 2) report the incidence of tendinopathy during the season; and 3) determine if the preseason presence of tendon abnormality is associated with onset of disease. One hundred and six female collegiate VB players had both patellar tendons imaged. Incidence of patellar tendinopathy was tracked during the course of the 4-month season. Twenty-two athletes presented with ultrasonographic evidence of patellar tendon abnormality in at least one knee at the start of the preseason. The incidence of time-loss patellar tendinopathy was 0.26 (95% CI: 0.04, 0.85) per 1000 athletic exposures. This study was unable to determine if preseason presence of tendon abnormality was associated with a greater risk of tendinopathy due to power. The prevalence of tendon abnormality in the preseason and the incidence of patellar tendinopathy in female collegiate VB players are lower than that observed in other populations.

Avoiding topsy-turvy: how Anna's hummingbirds (Calypte anna) fly through upward gusts.

Flying organisms frequently confront the challenge of maintaining stability when moving within highly dynamic airflows near the Earth's surface. Either aerodynamic or inertial forces generated by appendages and other structures, such as the tail, may be used to offset aerial perturbations, but these responses have not been well characterized. To better understand how hummingbirds modify wing and tail motions in response to individual gusts, we filmed Anna's hummingbirds as they negotiated an upward jet of fast-moving air. Birds exhibited large variation in wing elevation, tail pitch and tail fan angles among transits as they repeatedly negotiated the same gust, and often exhibited a dramatic decrease in body angle (29±6 deg) post-transit. After extracting three-dimensional kinematic features, we identified a spectrum of control strategies for gust transit, with one extreme involving continuous flapping, no tail fanning and little disruption to body posture (23±3 deg downward pitch), and the other extreme characterized by dorsal wing pausing, tail fanning and greater downward body pitch (38±4 deg). The use of a deflectable tail on a glider model transiting the same gust resulted in enhanced stability and can easily be implemented in the design of aerial robots.

Sex-hormone producing adrenal tumors causing behavioral changes as the sole clinical sign in 3 cats.

Three neutered cats with adrenocortical tumors that were presented with behavioral changes but no evidence of hyperaldosteronism or hypercortisolism are described. All 3 cats had resolution of their clinical signs following adrenalectomy. For neutered cats presenting with behavior changes, a sex-hormone secreting adrenal tumor should be considered as a differential diagnosis.

Tumeurs surrénaliennes produisant des hormones sexuelles causant des changements de comportement comme seul signe clinique chez 3 chats. Les cas de trois chats stérilisés ayant des tumeurs surrénaliennes qui ont été présentés avec des changements comportementaux mais aucun signe d'hyperaldostéronisme ou hypercortisolisme sont décrits. Les trois chats ont eu une résorption de leurs signes cliniques après une surrénalectomie. Pour les chats stérilisés présentant des changements comportementaux, une tumeur surrénalienne sécrétant des hormones sexuelles devrait être considérée comme un diagnostic différentiel.(Traduit par Isabelle Vallières).

Ascending flight and decelerating vertical glides in Anna's hummingbirds.

Hummingbirds are observationally well known for their capacity to vertically ascend whilst hovering, but the underlying mechanics and possible energetic limits to ascent rates are unclear. Decelerations during vertical ascent to a fixed target may also be associated with specific visual responses to regulate the body's trajectory. Here, we studied climbing flight and subsequent deceleration in male Anna's hummingbirds (Calypte anna) over an approximately 2 m vertical distance. Birds reached vertical speeds and accelerations up to ∼4 m s-1 and 10 m s-2, respectively, through the use of flapping frequencies as high as 56 Hz and stroke amplitudes slightly greater than 180 deg. Total mass-specific power at maximal ascent speed was up to 92 W kg-1 body mass. Near the end of the ascending trajectory, all individuals decelerated ballistically via cessation of flapping and folding of wings over the body without losing control, a behavior termed here a vertical glide. Visual modulation of the deceleration trajectory during ascent was indicated by a constant value (∼0.75) for the first derivative of the time-to-contact to target. Our results indicate that hummingbirds in rapid vertical ascent expended near-maximal power output during flight, but also tightly controlled their subsequent deceleration during the vertical glide.