Thirty-six years of butterfly monitoring, snow cover, and plant productivity reveal negative impacts of warmer winters and increased productivity on montane species.

Climate change is contributing to declines of insects through rising temperatures, altered precipitation patterns, and an increasing frequency of extreme events. The impacts of both gradual and sudden shifts in weather patterns are realized directly on insect physiology and indirectly through impacts on other trophic levels. Here, we investigated direct effects of seasonal weather on butterfly occurrences and indirect effects mediated by plant productivity using a temporally intensive butterfly monitoring dataset, in combination with high-resolution climate data and a remotely sensed indicator of plant primary productivity. Specifically, we used Bayesian hierarchical path analysis to quantify relationships between weather and weather-driven plant productivity on the occurrence of 94 butterfly species from three localities distributed across an elevational gradient. We found that snow pack exerted a strong direct positive effect on butterfly occurrence and that low snow pack was the primary driver of reductions during drought. Additionally, we found that plant primary productivity had a consistently negative effect on butterfly occurrence. These results highlight mechanisms of weather-driven declines in insect populations and the nuances of climate change effects involving snow melt, which have implications for ecological theories linking topographic complexity to ecological resilience in montane systems.

Optically detected magnetic resonance spectroscopic analyses on the role of magnetic ions in colloidal nanocrystals.

Incorporating magnetic ions into semiconductor nanocrystals has emerged as a prominent research field for manipulating spin-related properties. The magnetic ions within the host semiconductor experience spin-exchange interactions with photogenerated carriers and are often involved in the recombination routes, stimulating special magneto-optical effects. The current account presents a comparative study, emphasizing the impact of engineering nanostructures and selecting magnetic ions in shaping carrier-magnetic ion interactions. Various host materials, including the II-VI group, halide perovskites, and I-III-VI2 in diverse structural configurations such as core/shell quantum dots, seeded nanorods, and nanoplatelets, incorporated with magnetic ions such as Mn2+, Ni2+, and Cu1+/2+ are highlighted. These materials have recently been investigated by us using state-of-the-art steady-state and transient optically detected magnetic resonance (ODMR) spectroscopy to explore individual spin-dynamics between the photogenerated carriers and magnetic ions and their dependence on morphology, location, crystal composition, and type of the magnetic ion. The information extracted from the analyses of the ODMR spectra in those studies exposes fundamental physical parameters, such as g-factors, exchange coupling constants, and hyperfine interactions, together providing insights into the nature of the carrier (electron, hole, dopant), its local surroundings (isotropic/anisotropic), and spin dynamics. The findings illuminate the importance of ODMR spectroscopy in advancing our understanding of the role of magnetic ions in semiconductor nanocrystals and offer valuable knowledge for designing magnetic materials intended for various spin-related technologies.

Uncovering Multiple Intrinsic Chiral Phases in (PEA)2PbI4 Halide Perovskites.

Two-dimensional (2D) halide perovskites offer a unique platform for investigating the ground state of materials possessing significant anharmonicity. In contrast to three-dimensional perovskites, their 2D counterparts offer substantially fewer degrees of freedom, resulting in multiple well-defined crystal structures. In this work, we thoroughly investigate the anharmonic ground state of the benchmark (PEA)2PbI4 compound, using complementary information from low-temperature X-ray diffraction (XRD) and photoluminescence spectroscopy, supported by density functional theory calculations. We extrapolate four crystallographic configurations from low-temperature XRD. These configurations imply that the ground state has an intrinsic disorder stemming from two coexisting chiral sublattices, each with a bioriented organic spacer molecule. We further show evidence that these chiral structures form unevenly populated ground states, portraying uneven anharmonicity, where the state population may be tuned by surface effects. Our results uncover a disordered ground state that may induce intrinsic grain boundaries, which cannot be ignored in practical applications.

Effects of the COVID-19 pandemic on the outcome and mortality of patients with diabetic foot ulcer.

The outbreak of the coronavirus disease 2019 (COVID-19) led to events that significantly impaired the treatment and management of patients with chronic diabetes. Therefore, elective treatments at hospitals were cancelled and patients with chronic ailments were instructed to stay at home and minimise the time spent in public areas. The second was due to COVID-19-induced anxiety that deterred many patients from seeking care and adhering to periodic out-patient visits. In this study, we examined the short-term effects of the COVID-19 pandemic on patients with chronic diabetes who suffered from contaminated diabetic ulcers. We conducted a retrospective study with patients who had undergone amputations following diabetic ulcers during 2019-2020. The research group included diabetic amputees during the COVID-19 outbreak period ranging from March 2020 to December 2020. The control group included diabetic amputees from the corresponding period in 2019. Using the Wagner Scale, we measured the difference in the severity of ulcers upon the patient's initial admission. Additionally, we examined patient survival rates based on the size of amputations, by specifically focusing on the period between 1- and 6-months post-surgery. The results failed to suggest a clear and statistically significant worsening trend in the condition of patients in the research and control groups. Due to public lockdowns, transportation restrictions, scarcity of healthcare staff, and reduced adherence to exposure anxiety, patients with diabetic foot ulcers received inferior medical care during the COVID-19 pandemic. However, this study could not find a statistically significant difference in the mortality and major amputation rates in patients with diabetic ulcer before and during the pandemic. The health system should incorporate the existing institutional and technological recommendations to facilitate care and follow-up of patients with diabetic foot ulcers during the current and future pandemics.

Contrast Sensitivity Testing in Age-Related Macular Degeneration Using Motion Diamond Stimulus.

PURPOSE: This study was performed to characterize changes in contrast sensitivity (CS) that occur in patients with age-related macular degeneration (AMD) using a novel test, the motion diamond stimulus (MDS). METHODS: This was a cross-sectional study in which 20 subjects with unilateral exudative AMD (eAMD) and contralateral dry AMD received 3 assessments: the Pelli-Robson (PR) CS Chart, the MDS test, and a visual function questionnaire-25 (VFQ-25). CS results from the PR, and MDS tests were compared across 3 groups: eyes with eAMD vs dry AMD, eAMD vs control, dry AMD vs control. Healthy, undilated eyes from another study served as the control group. Significance was determined using ANOVA analysis for the MDS output parameters (α: overall contrast threshold, ß: adaptability of the visual system) and PR logCS. Patients were also administered the VFQ-25 to assess vision-related quality of life. RESULTS: The ANOVA of the MDS data demonstrated a significant difference in visual function according to the ß parameter of the 3 groups, but no significant difference in the α parameter. PR CS results for the 3 groups were significantly different, further supporting the MDS results. Post-hoc analysis showed a significant difference in ß and PR log CS between the eAMD and control eyes. CONCLUSION: The MDS test is valuable in discerning CS impairments in patients with AMD. It can provide further insight into the visual changes experienced by patients with AMD and has potential to quantify visual function changes that are not found on visual acuity testing alone.

Using a variant of the optomotor response as a visual defect detection assay in zebrafish.

We describe a visual stimulus that can be used with both larval and adult zebrafish (Danio rerio). This protocol is a modification of a standard visual behavior analysis, the optomotor response (OMR). The OMR is often used to determine the spatial response or to detect directional visuomotor deficiencies. An OMR can be generated using a high contrast grated pattern, typically vertical bars. The spatial sensitivity is measured by detection and response to a change in grating bar width and is reported in cycles per degree (CPD). This test has been used extensively with zebrafish larvae and adults to identify visual- and/or motor-based mutations. Historically, when tested in adults, the grated pattern was presented from a vertical perspective, using a rotating cylinder around a holding tank, allowing the grating to be seen solely from the sides and front of the organism. In contrast, OMRs in zebrafish larvae are elicited using a stimulus projected below the fish. This difference in methodology means that two different experimental set-ups are required: one for adults and one for larvae. Our visual stimulus modifies the stimulation format so that a single OMR stimulus, suitable for use with both adults and larvae, is being presented underneath the fish. Analysis of visuomotor responses using this method does not require costly behavioral tracking software and, using a single behavioral paradigm, allows the observer to rapidly determine visual spatial response in both zebrafish larvae and adults.

Insects and recent climate change.

Insects have diversified through more than 450 million y of Earth's changeable climate, yet rapidly shifting patterns of temperature and precipitation now pose novel challenges as they combine with decades of other anthropogenic stressors including the conversion and degradation of land. Here, we consider how insects are responding to recent climate change while summarizing the literature on long-term monitoring of insect populations in the context of climatic fluctuations. Results to date suggest that climate change impacts on insects have the potential to be considerable, even when compared with changes in land use. The importance of climate is illustrated with a case study from the butterflies of Northern California, where we find that population declines have been severe in high-elevation areas removed from the most immediate effects of habitat loss. These results shed light on the complexity of montane-adapted insects responding to changing abiotic conditions. We also consider methodological issues that would improve syntheses of results across long-term insect datasets and highlight directions for future empirical work.

Contrast Sensitivity Testing in Retinal Vein Occlusion Using a Novel Stimulus.

Purpose: This study evaluated a novel tool known as the motion diamond stimulus (MDS), which utilizes contrast-generated illusory motion in dynamic test regions to determine contrast sensitivity (CS). Methods: Patients with treated unilateral retinal vein occlusions (RVOs) underwent three assessments: the MDS, the Pelli-Robson (PR), and the National Eye Institute's Visual Function Questionnaire (VFQ-25). The MDS assessment produced two data end points, α and ß. The α value represents the overall contrast threshold level and the ß value serves to quantify the adaptability of the visual contrast system. The CS parameters from the MDS and log CS PR output values were used to compare RVO eyes (n = 20) to control eyes (n = 20). Results: The study participants had a mean composite VFQ-25 score of 89.5 ± 10.4 on the VFQ-25. A significant difference was observed between the RVO eyes and the control eyes in PR log CS scores (P value = 0.0001) and in MDS α value (P value = 0.01). No difference in MDS ß value was found between the study groups (P value = 0.39). Conclusions: The results for the MDS assessment's α parameter corroborated the PR scores, suggesting contrast sensitivity threshold impairment in patients with RVO. No significant difference in ß value was observed, suggesting that adaptability of the visual system is maintained in treated RVO eyes. Translational Relevance: Currently, visual complaints cannot be entirely identified by Snellen visual acuity alone. The MDS offers potentially a more complete look at visual function, by including contrast sensitivity and may be able to quantify changes otherwise overlooked in retinal disease progression.

Helix rotation: luminance contrast controls the shift from two-dimensional to three-dimensional perception.

We present the helix rotation phenomenon, an array of moving dots that creates a conflict between two potential perceptions: a 3D Pulfrich-like horizontal rotation and a low-spatial-frequency up-down motion. We show that observers perceive up-down motion when the dots are equiluminant with the background and when the display is blurred; that the addition of sparse luminance information to equiluminant and blurred displays produces 3D perception; and that the balance between the perception of 3D rotation and up-down motion depends on the magnitude of the luminance contrast. The results are discussed in terms of the luminance capture of equiluminant information.

Extreme heterogeneity of population response to climatic variation and the limits of prediction.

Certain general facets of biotic response to climate change, such as shifts in phenology and geographic distribution, are well characterized; however, it is not clear whether the observed similarity of responses across taxa will extend to variation in other population-level processes. We examined population response to climatic variation using long-term incidence data (collected over 42 years) encompassing 149 butterfly species and considerable habitat diversity (10 sites along an elevational gradient from sea level to over 2,700 m in California). Population responses were characterized by extreme heterogeneity that was not attributable to differences in species composition among sites. These results indicate that habitat heterogeneity might be a buffer against climate change and highlight important questions about mechanisms maintaining interpopulation differences in responses to weather. Despite overall heterogeneity of response, population dynamics were accurately predicted by our model for many species at each site. However, the overall correlation between observed and predicted incidence in a cross validation analysis was moderate (Pearson's r = 0.23, SE 0.01), and 97% of observed data fell within the predicted 95% credible intervals. Prediction was most successful for more abundant species as well as for sites with lower annual turnover. Population-level heterogeneity in response to climate variation and the limits of our predictive power highlight the challenges for a future of increasing climatic variability.

Fundamental Properties in Colloidal Quantum Dots.

A multidisciplinary approach for the production and characterization of colloidal quantum dots, which show great promise for implementation in modern optoelectronic applications, is described. The approach includes the design and formation of unique core/shell structures with alloy-composed layers between the core and the shell. Such structures eliminate interfacial defects and suppress the Auger process, thus reducing the known fluorescence blinking and endowing the quantum dots with robust chemical and spectral stability. The unique design enables the generation and sustained existence of single and multiple excitons with a defined spin-polarized emission recombination. The studies described herein implement the use of single-dot magneto-optical measurements and optically detected magnetic resonance spectroscopy, for direct identification of interfacial defects and for resolving exciton fine structure. The results are of paramount importance for a fundamental understanding of optical transitions in colloidal quantum dots, with an impact on appropriate materials design for practical applications.

Remote controls illusion: strange interactions across space cannot be explained by simple contrast filters.

The visual system has separable visual encoding for luminance and for contrast modulation [J. Vis.8(1), B152 (2008)1534-736210.1167/8.6.1]; the two dimensions can be represented with a luminance contrast versus luminance plane. Here we use a contrast asynchrony paradigm to explore contextual effects on luminance contrast modulation: two identical rectangular bars (0.5°×2.5°) have luminance levels that modulate at 2 Hz; when one bar is placed on a bright field and the other bar on a dark field, observers perceive the bars modulating in antiphase with each other and yet becoming light and dark at the same time. The antiphase perception corresponds to the change in contrast between the bars and their surrounds (a change along the contrast axis of the plane); the in-phase perception corresponds to the luminance modulation (a change along the luminance axis of the plane). We examine spatial interaction by adding bright rectangular (0.5°×2.5°) flankers on both sides of the dark-field bar and dark flankers on both sides of the bright-field bar. Remarkably, flankers produce an in-phase appearance when separated from the bars by between 2' and 4' of visual angle, and produce antiphase appearance when they directly adjoin the bars or are separated by more than 8'. To estimate the dimensions of the spatial interaction, we parametrically adjust the size of the gap between bars and flankers and the length of the flankers. We attempt to account for the results with models based on rectified difference of Gaussian filters and with rectified oriented difference of Gaussian filters. The models can account for the results when the flankers are the same height as bars, but are unable to account for the effects of increasing the flanker length. The models therefore suggest that the spatial interaction across distances requires more complex interactions of contrast filters.

Kitaoka's Tomato: Two Simple Explanations Based on Information in the Stimulus.

Kitaoka's Tomato is a color illusion in which a semitransparent blue-green field is placed on top of a red object (a tomato). The tomato appears red even though the pixels would appear green if viewed in isolation. We show that this phenomenon can be explained by a high-pass filter and by histogram equalization. The results suggest that this illusion does not require complex inferences about color constancy; rather, the tomato's red is available in the physical stimulus at the appropriate spatial scale and dynamic range.

The Perpetual Diamond: Contrast Reversals Along Thin Edges Create the Appearance of Motion in Objects.

The Perpetual Diamond produces motion continuously and unambiguously in one direction despite never physically changing location. The phenomenon consists of a steady, mid-luminance diamond bordered by four thin edge strips and a surrounding background field. The direction of motion is determined by the relative phases of the luminance modulation between the edge strips and the background. Because the motion is generated entirely by changing contrast signals between the edge strips and background, the stimulus is a valuable tool for tests of spatial contrast, temporal contrast, contrast gain, and color contrast. We demonstrate that observers see motion even when the edge strips subtend only seconds of arc on the retina (which is less than the frequently reported 10 minutes of arc) and that perceived motion is due entirely to changes in the difference in contrast phase modulation, independent from the luminance phase.

Synchronous population dynamics in California butterflies explained by climatic forcing.

A long-standing challenge for population biology has been to understand why some species are characterized by populations that fluctuate in size independently, while populations of other species fluctuate synchronously across space. The effects of climatic variation and dispersal have been invoked to explain synchronous population dynamics, however an understanding of the relative influence of these drivers in natural populations is lacking. Here we compare support for dispersal- versus climate-driven models of interspecific variation in synchrony using 27 years of observations of 65 butterfly species at 10 sites spanning 2750 m of elevation in Northern California. The degree of spatial synchrony exhibited by each butterfly species was used as a response in a unique approach that allowed us to investigate whether interspecific variation in response to climate or dispersal propensity was most predictive of interspecific variation in synchrony. We report that variation in sensitivity to climate explained 50% of interspecific variation in synchrony, whereas variation in dispersal propensity explained 23%. Sensitivity to the El Niño Southern Oscillation, a primary driver of regional climate, was the best predictor of synchrony. Combining sensitivity to climate and dispersal propensity into a single model did not greatly increase model performance, confirming the primacy of climatic sensitivity for driving spatial synchrony in butterflies. Finally, we uncovered a relationship between spatial synchrony and population decline that is consistent with theory, but small in magnitude, which suggests that the degree to which populations fluctuate in synchrony is of limited use for understanding the ongoing decline of the Northern California butterfly fauna.

Sympatric, temporally isolated populations of the pine white butterfly Neophasia menapia, are morphologically and genetically differentiated.

Temporal isolation remains an understudied, and potentially under-appreciated, mechanism of reproductive isolation. Phenological differences have been discovered in populations of the pine white butterfly (Neophasia menapia), a typically univoltine species found throughout western North America. At two locations in the Coast Range of California there are two periods of adult emergence per year, one in early summer (July) and one in late summer/autumn (September/October). Differences in flight time are accompanied by differences in wing shape and pigmentation. Here we use a combination of population genomics and morphological analyses to assess the extent to which temporal isolation is able to limit gene flow between sympatric early and late flights. Not only did we detect both genetic and morphological differences between early and late flights at the two sites, we also found that the patterns of differentiation between the two flights were different at each location, suggesting an independent origin for the two sympatric flights. Additionally, we found no evidence that these sympatric flights originated via colonization from any of the other sampled localities. We discuss several potential hypotheses about the origin of these temporally isolated sympatric flights.

Evidence of a link between fever and microscopic hematuria in children.

Despite the common conception that febrile illnesses are associated with microscopic hematuria in children, a review of the literature failed to disclose supportive evidence. The aim of this study was to evaluate this relationship. Background data were collected for a convenience sample of children aged 4-18 years who presented to the emergency department (ED) of a tertiary pediatric medical center. Vital signs were measured and a midstream urine specimen was collected. Specimens positive for the presence of blood (>5 erythrocytes/µl; Combur 10 Test Strips) were examined microscopically. Patients found to have microscopic hematuria (>5 erythrocytes/high power field) were asked to undergo repeated urine testing within 3 weeks or at least 1 week after the fever (if present) resolved. A telephone interview was conducted 9-10 years after the ED visit, for all children with microscopic hematuria. Data were coded and transferred to Microsoft Excel 2007 (Raymond Wa), and then analyzed using SPSS 15 (SPSS Inc., Chicago, IL). Six hundred sixty patients were enrolled in the study; 161 were febrile (mean temperature 39.2 ± .08 °C), and 499 were afebrile (mean temperature 36.7 ± 0.4 °C) (p < 0.001). The febrile group was significantly younger than the afebrile group (mean age 8 ± 3.6 years versus 9.4 ± 3.7 years, respectively, p < 0.001). There was no significant between-group difference in sex distribution (55 and 60% boys, respectively, p = 0.199). Microscopic hematuria was found in 12 children, 9 febrile (5.6%), and 3 afebrile (0.6%) (p < 0.001). All repeated urine tests (n = 12) were negative for microscopic hematuria. CONCLUSION: The findings suggest that fever is associated with transient microscopic hematuria in children. The study is limited by its single-center setting and relatively small sample. What is known: • It is commonly believed that fever increases the incidence of microscopic hematuria. • However, to the best of our knowledge, this assumption has not been proven. What is new: • This study demonstrates a significant association between fever and transient microscopic hematuria in children. • The transient nature of the hematuria may be reassuring for both parents and healthcare providers.

Spatial filtering, color constancy, and the color-changing dress.

The color-changing dress is a 2015 Internet phenomenon in which the colors in a picture of a dress are reported as blue-black by some observers and white-gold by others. The standard explanation is that observers make different inferences about the lighting (is the dress in shadow or bright yellow light?); based on these inferences, observers make a best guess about the reflectance of the dress. The assumption underlying this explanation is that reflectance is the key to color constancy because reflectance alone remains invariant under changes in lighting conditions. Here, we demonstrate an alternative type of invariance across illumination conditions: An object that appears to vary in color under blue, white, or yellow illumination does not change color in the high spatial frequency region. A first approximation to color constancy can therefore be accomplished by a high-pass filter that retains enough low spatial frequency content so as to not to completely desaturate the object. We demonstrate the implications of this idea on the Rubik's cube illusion; on a shirt placed under white, yellow, and blue illuminants; and on spatially filtered images of the dress. We hypothesize that observer perceptions of the dress's color vary because of individual differences in how the visual system extracts high and low spatial frequency color content from the environment, and we demonstrate cross-group differences in average sensitivity to low spatial frequency patterns.

Interface control of electronic and optical properties in IV-VI and II-VI core/shell colloidal quantum dots: a review.

Semiconductor colloidal quantum dots (CQDs) have attracted vast scientific and technological interest throughout the past three decades, due to the unique tuneability of their optoelectronic properties by variation of size and composition. However, the nanoscale size brings about a large surface-to-bulk volume ratio, where exterior surfaces have a pronounced influence on the chemical stability and on the physical properties of the semiconductor. Therefore, numerous approaches have been developed to gain efficient surface passivation, including a coverage by organic or inorganic molecular surfactants as well as the formation of core/shell heterostructures (a semiconductor core epitaxially covered by another semiconductor shell). This review focuses on special designs of core/shell heterostructures from the IV-VI and II-VI semiconductor compounds, and on synthetic approaches and characterization of the optical properties. Experimental observations revealed the formation of core/shell structures with type-I or quasi-type-II band alignment between the core and shell constituents. Theoretical calculations of the electronic band structures, which were also confirmed by experimental work, exposed surplus electronic tuning (beyond the radial diameter) with adaptation of the composition and control of the interface properties. The studies also considered strain effects that are created between two different semiconductors. It was disclosed experimentally and theoretically that the strain can be released via the formation of alloys at the core-shell interface. Overall, the core/shell and core/alloyed-shell heterostructures showed enhancement in luminescence quantum efficiency with respect to that of pure cores, extended lifetime, uniformity in size and in many cases good chemical sustainability under ambient conditions.