The wings of Lepidoptera contain a matrix of living cells whose function requires appropriate temperatures. However, given their small thermal capacity, wings can overheat rapidly in the sun. Here we ...analyze butterfly wings across a wide range of simulated environmental conditions, and find that regions containing living cells are maintained at cooler temperatures. Diverse scale nanostructures and non-uniform cuticle thicknesses create a heterogeneous distribution of radiative cooling that selectively reduces the temperature of structures such as wing veins and androconial organs. These tissues are supplied by circulatory, neural and tracheal systems throughout the adult lifetime, indicating that the insect wing is a dynamic, living structure. Behavioral assays show that butterflies use wings to sense visible and infrared radiation, responding with specialized behaviors to prevent overheating of their wings. Our work highlights the physiological importance of wing temperature and how it is exquisitely regulated by structural and behavioral adaptations.
The Australian lycaenid butterfly Jalmenus evagoras has iridescent wings that are sexually dimorphic, spectrally and in their degree of polarization, suggesting that these properties are likely to be ...important in mate recognition. We first describe the results of a field experiment showing that free-flying individuals of J. evagoras discriminate between visual stimuli that vary in polarization content in blue wavelengths but not in others. We then present detailed reflectance spectrophotometry measurements of the polarization content of male and female wings, showing that female wings exhibit blue-shifted reflectance, with a lower degree of polarization relative to male wings. Finally, we describe a novel method for measuring alignment of ommatidial arrays: by measuring variation of depolarized eyeshine intensity from patches of ommatidia as a function of eye rotation, we show that (a) individual rhabdoms contain mutually perpendicular microvilli; (b) many rhabdoms in the array have their microvilli misaligned with respect to neighboring rhabdoms by as much as 45 deg; and (c) the misaligned ommatidia are useful for robust polarization detection. By mapping the distribution of the ommatidial misalignments in eye patches of J. evagoras, we show that males and females exhibit differences in the extent to which ommatidia are aligned. Both the number of misaligned ommatidia suitable for robust polarization detection and the number of aligned ommatidia suitable for edge detection vary with respect to both sex and eye patch elevation. Thus, J. evagoras exhibits finely tuned ommatidial arrays suitable for perception of polarized signals, likely to match sex-specific life history differences in the utility of polarized signals.
Infantile hepatic hemangioma (IHH) is a rare but life-threatening disorder that must be considered in the newborn presenting with high-output heart failure (HF). IHH is a tumor comprised of large ...vascular beds, which require a significant increase in blood flow as the lesion grows. This, in turn, creates an undue burden on the cardiovascular system, leading to high-output HF and potentially, respiratory distress. Recent changes have been made in the classification of certain hepatic hemangiomas and their treatments.
A 10-day-old girl presented to the Emergency Department with increased respiratory effort and an episode of apnea and cyanosis. A chest x-ray study was obtained and showed cardiomegaly and pulmonary edema concerning for HF. The patient was promptly admitted to the pediatric intensive care unit, where advanced imaging was obtained revealing findings consistent with IHH.
HF in an infant is a critical condition often requiring prompt intervention and rapid diagnosis of the correct etiology to save a life. IHH is an example of an extrathoracic etiology of pediatric HF that has undergone recent changes in terminology and diagnosis. Increased awareness among emergency physicians of this disease process and its treatments can lead to expeditious diagnosis and treatment of this potentially life-threatening illness.
Assessing decapod sensitivity to regional-scale ocean acidification (OA) conditions is limited because of a fragmented understanding of the thresholds at which they exhibit biological response. To ...address this need, we undertook a three-step data synthesis: first, we compiled a dataset composed of 27,000 datapoints from 55 studies of decapod responses to OA. Second, we used statistical threshold analyses to identify OA thresholds using pH as a proxy for 13 response pathways from physiology to behavior, growth, development and survival. Third, we worked with the panel of experts to review these thresholds, considering the contributing datasets based on quality of the study, and assign a final thresholds and associated confidence scores based on quality and consistency of findings among studies. The duration-dependent thresholds were within a pH range from 7.40 to 7.80, ranging from behavioral and physiological responses to mortality, with many of the thresholds being assigned medium-to-high confidence. Organism sensitivity increased with the duration of exposure but was not linked to a specific life-stage. The thresholds that emerge from our analyses provide the foundation for consistent interpretation of OA monitoring data or numerical ocean model simulations to support climate change marine vulnerability assessments and evaluation of ocean management strategies.
Fire is a major selective force on arid grassland communities, favoring traits such as the smoke‐induced seed germination response seen in a wide variety of plant species. However, little is known ...about the relevance of smoke as a cue for plants beyond the seedling stage.
We exposed a fire‐adapted savanna tree, Vachellia (=Acacia) drepanolobium, to smoke and compared nutrient concentrations in leaf and root tissues to unexposed controls. Experiments were performed on three age cohorts: 2‐year‐old, 9‐month‐old, and 3‐month‐old plants.
For the 2‐year‐old plants exposed to smoke, carbon and nitrogen concentrations were lower in the leaves and higher in the roots than controls. Less pronounced trends were found for boron and magnesium.
In contrast, smoke‐exposed 3‐month‐old plants had lower root nitrogen concentrations than controls. No significant differences were found in the 9‐month‐old plants, and no significant shifts in other nutrient concentrations were observed between plant tissues for any of the three age cohorts.
Synthesis: Our findings are consistent with smoke‐induced translocation of nutrients from leaves to roots in 2‐year‐old V. drepanolobium. This could represent a novel form of fire adaptation, with variation over the course of plant development. The translocation differences between age cohorts highlight the need to investigate smoke response in older plants of other species. Accounting for this adaptation could better inform our understanding of savanna community structure and nutrient flows under fire regimes altered by anthropogenic land use and climate change.
We exposed a fire‐adapted savanna tree, Vachellia (=Acacia) drepanolobium, to smoke and compared nutrient concentrations in leaf and root tissues to unexposed controls. Our findings suggest trees may detect smoke and respond by translocating nutrients from leaves to roots, a potential mechanism for improving survival and post‐fire resprouting.
We present an economical imaging system with integrated hardware and software to capture multispectral images of Lepidoptera with high efficiency. This method facilitates the comparison of colors and ...shapes among species at fine and broad taxonomic scales and may be adapted for other insect orders with greater three-dimensionality. Our system can image both the dorsal and ventral sides of pinned specimens. Together with our processing pipeline, the descriptive data can be used to systematically investigate multispectral colors and shapes based on full-wing reconstruction and a universally applicable ground plan that objectively quantifies wing patterns for species with different wing shapes (including tails) and venation systems. Basic morphological measurements, such as body length, thorax width, and antenna size are automatically generated. This system can increase exponentially the amount and quality of trait data extracted from museum specimens.
We examined the use of antibiotics for acute respiratory infections in an urgent-care setting.
Retrospective database review.
The study was conducted in 2 urgent-care clinics staffed by academic ...emergency physicians in San Diego, California.
Visits for acute respiratory infections were identified based on presenting complaints.
The primary outcome was a discharge prescription for an antibiotic. The patient and provider characteristics that predicted this outcome were analyzed using logistic regression. The variation in antibiotic prescriptions between providers was also analyzed.
In total, 15,160 visits were analyzed. The patient characteristics were not predictive of antibiotic treatment. Physicians were more likely than advanced practice practitioners to prescribe antibiotics (1.31; 95% confidence interval CI, 1.21-1.42). For every year of seniority, a provider was 1.03 (95% CI, 1.02-1.03) more likely to prescribe an antibiotic. Although the providers saw similar patients, we detected significant variation in the antibiotic prescription rate between providers: the mean antibiotic prescription rate within the top quartile was 54.3% and the mean rate in the bottom quartile was 21.7%.
The patient and provider characteristics we examined were either not predictive or were only weakly predictive of receiving an antibiotic prescription for acute respiratory infection. However, we detected a marked variation between providers in the rate of antibiotic prescription. Provider differences, not patient differences, drive variations in antibiotic prescriptions. Stewardship efforts may be more effective if directed at providers rather than patients.
Exposing patients with a low probability of disease to diagnostic testing with poor test characteristics leads to false positive results. Providers often act on these false results, which can cause ...unnecessary evaluation and treatment. The treatment of asymptomatic bacteriuria is discouraged, but it still frequently occurs in the inpatient setting; it is less studied in the Emergency Department (ED). In this study, we examine associations between urine testing, inappropriate antibiotic use, and length of stay in discharged ED patients at risk of urinary tract infection (UTI) misdiagnosis.
A cohort of discharged ED patients at risk of UTI misdiagnosis was created by pulling visit information for patients presenting with abdominal pain, chest pain, headache, vaginal bleeding in pregnancy, and elderly females with weakness or confusion. Predictors of urine testing, and urinary tract infection treatment were determined with logistic regression analysis. A chart review of a representative sample of this cohort was then completed screening for the presence of urinary tract symptoms and urine culture results. Linear regression analysis was then used to generate an adjusted mean difference in length of stay between patients who had urine testing compared to those who did not.
About a quarter of chest pain and headache patients had urine testing, while approximately 75% of abdominal pain patients, vaginal bleeding in pregnancy, and elderly females with weakness or confusion did. Except for chest pain patients, the UTI treatment rate was more than double the positive culture rate, indicating overtreatment. A diagnosis of UTI is based on a combination of UTI symptoms and positive urine cultures, yet only about 15% of patients treated for UTI met these criteria. Lastly, in all chief complaint groups, the length of stay was significantly longer—30 min or more—for those who had urine testing compared to matched controls.
In this observational study of patients at risk of UTI misdiagnosis, urine testing was associated with inappropriate antibiotic use and delayed discharge. There is pressure on providers to perform diagnostic testing, but in patients without specific UTI symptoms, urine testing might cause more harm than benefit.
Urinary tract infections; Asymptomatic bacteriuria; Antibiotic stewardship; Length of stay.
Color vision has evolved multiple times in both vertebrates and invertebrates and is largely determined by the number and variation in spectral sensitivities of distinct opsin subclasses. However, ...because of the difficulty of expressing long-wavelength (LW) invertebrate opsins in vitro, our understanding of the molecular basis of functional shifts in opsin spectral sensitivities has been biased toward research primarily in vertebrates. This has restricted our ability to address whether invertebrate G
protein-coupled opsins function in a novel or convergent way compared to vertebrate G
opsins. Here we develop a robust heterologous expression system to purify invertebrate rhodopsins, identify specific amino acid changes responsible for adaptive spectral tuning, and pinpoint how molecular variation in invertebrate opsins underlie wavelength sensitivity shifts that enhance visual perception. By combining functional and optophysiological approaches, we disentangle the relative contributions of lateral filtering pigments from red-shifted LW and blue short-wavelength opsins expressed in distinct photoreceptor cells of individual ommatidia. We use in situ hybridization to visualize six ommatidial classes in the compound eye of a lycaenid butterfly with a four-opsin visual system. We show experimentally that certain key tuning residues underlying green spectral shifts in blue opsin paralogs have evolved repeatedly among short-wavelength opsin lineages. Taken together, our results demonstrate the interplay between regulatory and adaptive evolution at multiple G
opsin loci, as well as how coordinated spectral shifts in LW and blue opsins can act together to enhance insect spectral sensitivity at blue and red wavelengths for visual performance adaptation.
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