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1,709 results for “Reflectivity”
Data from: Isotopic niche reflects stress-induced variability in physiological status
The isotopic niche has become an established concept in trophic ecology. However, the assumptions behind this approach have rarely been evaluated. The evidence is accumulating that physiological stress can affect both magnitude and inter-individual variability of the isotopic signature in consumers via alterations in metabolic pathways. We hypothesized that stress factors (inadequate nutrition, parasite infestations, and exposure to toxic substances or varying oxygen conditions) might lead to suboptimal physiological performance and altered stable isotope signatures. The latter can be misinterpreted as alterations in isotopic niche. This hypothesis was tested by inducing physiological stress in the deposit-feeding amphipod Monoporeia affinis exposed to either different feeding regimes or contaminated sediments. In the amphipods, we measured body condition indices or reproductive output to assess growth status and δ13C and δ15N values to derive isotope niche metrics. As hypothesized, greater isotopic niche estimates were derived for the stressed animals compared to the control groups. Moreover, the δ15N values were influenced by body size, reproductive status and parasite infestations, while δ13C values were influenced by body size, oxygen conditions and survival. Using regression analysis with isotope composition and growth variables as predictors, we were able to discriminate between the amphipods exposed to nutritionally or chemically stressful conditions and those in the control groups. Thus, interpretation of isotopic niche can be confounded by natural or anthropogenic stressors that may induce an apparent rather than a dietary change in isotopic niche. These findings stress the importance of including measures of growth and health status when evaluating stable isotope data in food web studies.
Data from: Cluster analysis successfully identifies clinically meaningful knee valgus moment patterns: frequency of early peaks reflects sex-specific ACL injury incidence
Background: Biomechanical studies of ACL injury risk factors frequently analyze only a fraction of the relevant data, and typically not in accordance with the injury mechanism. Extracting a peak value within a time series of relevance to ACL injuries is challenging due to differences in the relative timing and size of the peak value of interest. Aims/hypotheses: The aim was to cluster analyze the knee valgus moment time series curve shape in the early stance phase. We hypothesized that 1a) There would be few discrete curve shapes, 1b) there would be a shape reflecting an early peak of the knee valgus moment, 2a) youth athletes of both sexes would show similar frequencies of early peaks, 2b) adolescent girls would have greater early peak frequencies. Methods: N = 213 (39% boys) youth soccer and team handball athletes (phase 1) and N = 35 (45% boys) with 5 year follow-up data (phase 2) were recorded performing a change of direction task with 3D motion analysis and a force plate. The time series of the first 30% of stance phase were cluster analyzed based on Euclidean distances in two steps; shape-based main clusters with a transformed time series, and magnitude based sub-clusters with body weight normalized time series. Group differences (sex, phase) in curve shape frequencies, and shape-magnitude frequencies were tested with chi-squared tests. Results: Six discrete shape-clusters and 14 magnitude based sub-clusters were formed. Phase 1 boys had greater frequency of early peaks than phase 1 girls (38% vs 25% respectively, P < 0.001 for full test). Phase 2 girls had greater frequency of early peaks than phase 2 boys (42% vs 21% respectively, P < 0.001 for full test). Conclusions: Cluster analysis can reveal different patterns of curve shapes in biomechanical data, which likely reflect different movement strategies. The early peak shape is relatable to the ACL injury mechanism as the timing of its peak moment is consistent with the timing of injury. Greater frequency of early peaks demonstrated by Phase 2 girls is consistent with their higher risk of ACL injury in sports.
Data from: Gut microbiome composition and metabolomic profiles of wild western lowland gorillas (Gorilla gorilla gorilla) reflect host ecology
The metabolic activities of gut microbes significantly influence host physiology; thus, characterizing the forces that modulate this micro-ecosystem is key to understanding mammalian biology and fitness. To investigate the gut microbiome of wild primates and determine how these microbial communities respond to the host's external environment, we characterized faecal bacterial communities and, for the first time, gut metabolomes of four wild lowland gorilla groups in the Dzanga-Sangha Protected Areas, Central African Republic. Results show that geographical range may be an important modulator of the gut microbiomes and metabolomes of these gorilla groups. Distinctions seemed to relate to feeding behaviour, implying energy harvest through increased fruit consumption or fermentation of highly fibrous foods. These observations were supported by differential abundance of metabolites and bacterial taxa associated with the metabolism of cellulose, phenolics, organic acids, simple sugars, lipids and sterols between gorillas occupying different geographical ranges. Additionally, the gut microbiomes of a gorilla group under increased anthropogenic pressure could always be distinguished from that of all other groups. By characterizing the interplay between environment, behaviour, diet and symbiotic gut microbes, we present an alternative perspective on primate ecology and on the forces that shape the gut microbiomes of wild primates from an evolutionary context.
Data from: Fine-scale spatiotemporal patterns of genetic variation reflect budding dispersal coupled with strong natal philopatry in a cooperatively breeding mammal
The relatedness structure of animal populations is thought to be a critically important factor underlying the evolution of mating systems and social behaviours. While previous work has shown that population structure is shaped by many biological processes, few studies have investigated how these factors vary over time. Consequently, we explored the fine-scale spatiotemporal genetic structure of an intensively studied population of cooperatively breeding banded mongooses (Mungos mungo) over a ten-year period. Overall population structure was strong (average Fst = 0.129) but groups with spatially overlapping territories were not more genetically similar to one another than non-contiguous groups. Instead, genetic differentiation was associated with historical group-fission (budding) events, with new groups diverging from their parent groups over time. Within groups, relatedness was high within but not between the sexes, although the latter increased over time since group formation due to group founders being replaced by philopatric young. This trend was not mirrored by a decrease in average offspring heterozygosity over time, suggesting that close inbreeding may often be avoided, even when immigration into established groups is virtually absent and opportunities for extra-group matings are rare. Fine-scale spatiotemporal population structure could have important implications in social species, where relatedness between interacting individuals is a vital component in the evolution of patterns of inbreeding avoidance, reproductive skew and kin-selected helping and harming.
Data from: Directional reflectance and milli-scale feather morphology of the African Emerald Cuckoo, Chrysococcyx cupreus
Diverse plumages have evolved among birds through complex morphological modifications. We investigate how the interplay of light with surface and subsurface feather morphology determines the direction of light propagation, an understudied aspect of avian visual signalling. We hypothesize that milli-scale modifications of feathers produce anisotropic reflectance, the direction of which may be predicted by the orientation of the milli-scale structure. The subject of this study is the African Emerald Cuckoo, Chrysococcyx cupreus, noted for its shimmering green iridescent appearance. Using a spherical gantry, we measured the change in the directional reflectance across the feather surface and over a hemisphere of incident lighting directions. Using a microCT scanner, we also studied the morphology of the structural branches of the barb. We tracked the changes in the directional reflectance to the orientation of the structural branches as observed in the CT data. We conclude that (i) the far-field signal of the feather consists of multiple specular components, each associated with a different structural branch and (ii) the direction of each specular component is correlated to the orientation of the corresponding structure.
Data from: Reinvestigation of Protelytron permianum (Insecta; Early Permian; USA) as an example for applying reflectance transformation imaging to insect imprint fossils
We reinvestigated the holotype of Protelytron permianum, one of the earliest putative stem-dermapteran (i.e. stem-earwig). We recurred to reflectance transformation imaging (RTI) to deliver exhaustive and interactive photographic data. We were able to ascertain the occurrence of broadenings located along veins of the hind wing vannus and forming an arc, as well as a series of radiating folds, alternatively concave and convex. Such an organization is diagnostic of Dermaptera, in which it is indicative of hind wing folding mechanisms, particularly elaborated in these insects. We provide a foldable, paper model of the hind wing. Based on the case presented herein we anticipate that RTI process will be a major upheaval in the documentation of fossil insects preserved as imprints.
Data from: Interaction networks of macrofungi and mycophagous beetles reflect diurnal variation and the size and spatial arrangement of resources
Ecological networks are useful for characterizing interspecific associations and predicting the resilience of ecological communities. We evaluated how such networks vary with the size, spatial distribution, and timing of availability of resources, with a focus on beetle-macrofungal associations. We used 2 y of field experiments to construct ecological networks based on manipulated sporocarp baits (resources; Pleurotus ostreatus) and natural communities of beetles (consumers) in a temperate forest. Centrality and interaction strength increased with resource size, but were associated weakly with resource density and isolation, and not at all with position within patches. Whole-network connectance was greater in mornings (when beetle richness and abundance were high) than evenings. Interannual differences in networks were consistent with differences in beetle communities between years. The capacity of networks to vary temporally, spatially, and as a function of resource traits is examined in light of understanding beetle-macrofungal associations, which are important components of fungal ecology.
Data from: Early wasp plucks the flower: disparate extant diversity of sawfly superfamilies (Hymenoptera: 'Symphyta') may reflect asynchronous switching to angiosperm hosts
The insect order Hymenoptera originated during the Permian nearly 300 million years ago. Ancestrally herbivorous hymenopteran lineages today make up the paraphyletic suborder 'Symphyta,' which encompasses circa 8200 species with very diverse host-plant associations. We used phylogeny-based statistical analyses to explore drivers of diversity dynamics within the 'Symphyta,' with a particular focus on the hypothesis that diversification of herbivorous insects has been driven by the explosive radiation of angiosperms during and after the Cretaceous. Our ancestral-state estimates reveal that the first symphytans fed on gymnosperms, and that shifts onto angiosperms and pteridophytes—and back—have occurred at different time intervals in different groups. Trait-dependent analyses indicate that average net diversification rates do not differ between symphytan lineages feeding on angiosperms, gymnosperms, or pteridophytes, but trait-independent models show that the highest diversification rates are found in a few angiosperm-feeding lineages that may have been favored by the radiations of their host taxa during the Cenozoic. Intriguingly, lineages-through-time plots exhibit signs of an early Cretaceous mass extinction, with a recovery starting first in angiosperm-associated clades. Hence, the oft-invoked assumption of herbivore diversification driven by the rise of flowering plants may overlook a Cretaceous global turnover in insect herbivore communities during the rapid displacement of gymnosperm- and pteridophyte-dominated floras by angiosperms.
Data from: Fish faunal provinces of the conterminous United States of America reflect historical geography and familial composition
Although the conterminous USA has a long history of ichthyological exploration, the description of biogeographical provinces has been ad hoc. In this study we quantitatively determined fish faunal provinces and interpreted them in the context of the geological history of North America. We also evaluated influences of major river basin occupancy and contemporary environmental factors on provincial patterns. Our data set comprised 794 native fishes, which we used to generate a presence and absence matrix for U.S. Geological Survey (USGS) four-digit hydrologic units. Three nested data sets were analysed separately: primary freshwater families, continental freshwater families (including primary and secondary families) and all freshwater families (including primary, secondary and peripheral families). We used clustering analysis to delimit faunal breaks and one-way analysis of similarity (ANOSIM) to determine significance among clusters (i.e. provinces). We used an indicator-species analysis to identify species that contributed most to province delineations and a similarity-percentage (SIMPER) analysis to describe the relative influence of representatives from each category (i.e. primary, secondary, peripheral) on provincial boundaries. Lastly, we used a parsimony redundancy analysis to determine the roles of historical (i.e. major river basin) and contemporary environmental factors in shaping provinces. Analysis of the nested data sets revealed lessening provincial structure with inclusion of more families. There were 10 primary freshwater provinces, 9 continental freshwater provinces and 7 all freshwater provinces. Major basin occupancy, but not contemporary environmental factors, explained substantial variance in faunal similarities among provinces. However, provincial boundaries did not conform strictly to modern river basins, but reflected river-drainage connections of the Quaternary. Provinces represent broad-scale patterns of endemism and provide a starting point for future studies. Relative malleability of province boundaries in the continental interior highlights this region as biogeographically diverse and dynamic. Interior-core provinces of this region (Central Gulf Coastal Plains, Northern Interior) have not been recognized previously and warrant further study.
Data from: Diet adaptation in dog reflects spread of prehistoric agriculture
Adaptations allowing dogs to thrive on a diet rich in starch, including a significant AMY2B copy number gain, constituted a crucial step in the evolution of the dog from the wolf. It is however not clear if this change was associated with the initial domestication or represents a secondary shift related to the subsequent development of agriculture. Previous efforts to study this process were based on geographically limited data sets and low-resolution methods and it is therefore not known to what extent the diet adaptations are universal among dogs and whether there are regional differences associated with alternative human subsistence strategies. Here we use droplet PCR to investigate worldwide AMY2B copy number diversity among indigenous as well as breed dogs and wolves to elucidate how a change in dog diet was associated with the domestication process and subsequent shifts in human subsistence. We find that AMY2B copy numbers are bimodally distributed with high copy numbers (median 2nAMY2B=11) in a majority of dogs but no, or few, duplications (median 2nAMY2B=3) in a small group of dogs originating mostly in Australia and the arctic. We show that this patterns correlates geographically to the spread of prehistoric agriculture and conclude that the diet change may not have been associated with initial domestication but rather the subsequent development and spread of agriculture to most, but not all regions of the globe.
Data from: Climate is a strong predictor of near-infrared reflectance but a poor predictor of colour in butterflies
Colour variation across climatic gradients is a common ecogeographical pattern; yet there is long-standing contention over underlying causes, particularly selection for thermal benefits. We tested the evolutionary association between climate gradients and reflectance of near-infrared (NIR) wavelengths, which influence heat gain but are not visible to animals. We measured ultraviolet, visible and NIR reflectance from calibrated images of 372 butterfly specimens from 60 populations (49 species, 5 families) spanning the Australian continent. Consistent with selection for thermal benefits, the association between climate and reflectance was stronger (slope and effect size) for NIR than UVA-visible wavelengths. Furthermore, climate predicted reflectance of the thorax and basal wing, which are critical to thermoregulation; but did not predict reflectance of the entire wing, which has a variable role in thermoregulation depending on basking behaviour. These results provide evidence that selection for thermal benefits has shaped the reflectance properties of butterflies.
Data from: Asymmetric hybridization and gene flow between Joshua trees (Agavaceae: Yucca) reflects differences in pollinator host specificity.
The angiosperms are by far the largest group of terrestrial plants. Their spectacular diversity is often attributed to specialized pollination. Obligate pollination mutualisms where both a plant and its pollinator are dependent upon one another for reproduction are thought to be prone to rapid diversification through co-evolution and pollinator isolation. However, few studies have evaluated the degree to which pollinators actually mediate reproductive isolation in these systems. Here, we examine evidence for hybridization and gene flow between two subspecies of Joshua tree (Yucca brevifolia brevifolia and Yucca brevifolia jaegeriana) pollinated by two sister species of yucca moth. Previous work indicated that the pollinators differ in host specificity, and DNA sequence data suggested asymmetric introgression between the tree subspecies. Through intensive sampling in a zone of sympatry, a large number of morphologically intermediate trees were identified. These included trees with floral characters typical of Y. b. jaegeriana, but vegetative features typical of Y. b. brevifolia. The opposite combination—Y. b. brevifolia flowers with Y. b. jaegeriana vegetative morphology—never occurred. Microsatellite genotyping revealed a high frequency of genetically admixed, hybrid trees. Coalescent-based estimates of migration indicated significant gene flow between the subspecies and that the direction of gene flow matches differences in pollinator host fidelity. The data suggest that pollinator behaviour determines the magnitude and direction of gene flow between the two subspecies, but that specialized pollination alone is not sufficient to maintain species boundaries. Natural selection may be required to maintain phenotypic differences in the face of ongoing gene flow.
Data from: Dissecting the variation of a visual trait: the proximate basis of UV-Visible reflectance in crab spiders (Thomisidae)
1. The astounding diversity of animal colouration is indicative of a wide variety of selection pressures. Despite great interest in adaptive function, detailed understanding of the constituent elements of colour traits is lacking for many systems. Such information is important in allowing more accurate appraisals of colour variation and its potential production costs. 2. In this study, we 'dissect' the dorsal colour of crab spiders (Thomisidae) to examine the mechanistic basis of a polyphenic colour trait. These spiders possess the ability to alter reflectance in the ultraviolet (UV), violet and blue wavelengths, changing their colour within days. We investigate and compare the proximate mechanistic basis of colour production in multiple phenotypes of three species using histology and spectrophotometry. 3. Our analyses indicate that the spider cuticle is not equivalently transparent to light across the spectrum (300-700 nm) – as previously argued – and contributes to colour variation. UV light is reflected from guanine crystals, present in storage cells ventral to the hypodermis. The crystals are exposed through a partially UV-transmitting hypodermis and cuticle. Variation from white to yellow is likely mediated through pigments/crystals present in different oxidative stages in the hypodermal cells. 4. Simple mechanistic changes are therefore necessary to produce the observed variation, and likely underlie the evolutionary and ontogenetic lability of this trait. Our findings imply that either a UV-reflective abdomen was the ancestral state for crab spiders, or, if pre-dated by UV-absorbent hypodermal pigments, the evolution of UV-reflection has only involved the exposure of underlying guanine crystals through an otherwise clear hypodermis.
Data from: Phylogeography of a widespread lizard complex reflects patterns of both geographic and ecological isolation
A primary challenge for modern phylogeography is understanding how ecology and geography, both contemporary and historical, shape the spatial distribution and evolutionary histories of species. Phylogeographic patterns are the result of many factors, including geology, climate, habitat, colonization history, and lineage-specific constraints. Assessing the relative influences of these factors is difficult because few species, regions, and environments are sampled in enough detail to compare competing hypotheses rigorously and because a particular phylogeographic pattern can potentially result from different evolutionary scenarios. The silky anoles (Anolis sericeus complex) of Central America and Mexico are abundant and found in all types of lowland terrestrial habitat, offering an excellent opportunity to test the relative influences of the factors affecting diversification. Here, we performed a range-wide statistical phylogeographic analysis on restriction-site associated DNA (RAD) markers from silky anoles and compared the phylogeographic patterns we recovered to historical and contemporary environmental and topographic data. We constructed niche models to compare niche overlap between sister lineages and conducted coalescent simulations to characterize how the major lineages of silky anoles have diverged. Our results revealed that the mode of divergence for major lineage diversification events was geographic isolation, resulting in ecological divergence between lineages, followed by secondary contact. Moreover, comparisons of parapatric sister lineages suggest that ecological niche divergence contributed to isolation by environment in this system, reflecting the natural history differences among populations in divergent environments.
LiDAR scan of Anton Smit's "Reflect" statue
iPhone 12 Pro Max LiDAR scan of Anton Smit's "Reflect" collection of statues at Leonardslee Gardens, UK. Captured with Scaniverse Source: Objaverse 1.0 / Sketchfab
FIGURE 4. Mean reflectance spectra for ten body regions measured from three Melozone leucotis subspecies, M. l in Phenotypic variation and vocal divergence reveals a species complex in White-eared Ground-sparrows (Cabanis) (Aves: Passerellidae)
FIGURE 4. Mean reflectance spectra for ten body regions measured from three Melozone leucotis subspecies, M. l. leucotis (solid lines, N = 13), M. l. nigrior (dotted lines, N = 13), and M. l. occipitalis (dashed lines, N = 8). The gray area around each line represents standard error of the mean calculated at every 1nm.
Calibration Bias Evaluation and Correction of S-Band Ground-Based Radar Reflectivity Using Ku-Band Space-Borne Radar Observations Along the East Coast of India
Open the record for dataset details and reuse information.
UV Reflectance of Spacecraft Materials and Analog Soils: Implications for Bioburden Reductions on the Undersides of Mars Rovers
<p><strong>Abstract</strong></p><p>The Mars Sample Return mission architecture will utilize three spacecraft to collect, cache, recover, launch, and return to Earth a diversity of regolith and rock samples. However, no comprehensive Mars Microbial Survival (MMS) model currently exists. As an initial effort in building a MMS model, we examined the UV reflectance of 15 spacecraft materials and seven Mars analog soils within the context of the Perseverance mission. Data were used to predict the times required to achieve one lethal dose (syn., Sterility Assurance Level [SAL]; def. as a bioburden reduction of ‒12 logs). Results suggest that a single SAL dosage of UVC was achieved on exposed surfaces on the upper deck of Perseverance within a few hours to a few sols post-landing at Jezero Crater. The overall average for UVC reflectance from spacecraft materials was approx. 10%. The overall UVC reflectance from Mars analog soils was measured at 1.3%. The Adaptive Caching Assembly (ACA) on Perseverance is located on the forward edge of the underbelly of the spacecraft. Modeling of the accumulated UVC dosage for the ACA yielded a prediction of reaching one SAL for downward facing surfaces at 93 sols that receive 'single bounce' UVC photons from the local terrain. The SAL increases to 930 sols, if an additional '<i>bounce</i>' of the solar UV irradiation is required to reach a partially protected site in the ACA hardware. The current study is the first to report on the UVC reflectance from a diversity of spacecraft materials. </p>
Malaria disease and grading system dataset from public hospitals reflecting complicated and uncomplicated conditions
<p>Malaria is the leading cause of death in the African region. Data mining can help extract valuable knowledge from available data in the healthcare sector. This makes it possible to train models to predict patient health faster than in clinical trials. Implementations of various machine learning algorithms such as K-Nearest Neighbors, Bayes Theorem, Logistic Regression, Support Vector Machines, and Multinomial Naïve Bayes (MNB), etc., has been applied to malaria datasets in public hospitals, but there are still limitations in modeling using the Naive Bayes multinomial algorithm. This study applies the MNB model to explore the relationship between 15 relevant attributes of public hospitals data. The goal is to examine how the dependency between attributes affects the performance of the classifier. MNB creates transparent and reliable graphical representation between attributes with the ability to predict new situations. The model (MNB) has 97% accuracy. It is concluded that this model outperforms the GNB classifier which has 100% accuracy and the RF which also has 100% accuracy.</p>
Synthetic-reflection self-injection-locked microcombs
<p>Data and code used in the manuscript "Synthetic-reflection self-injection-locked microcombs".</p>
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