1,565 research outputs found

    Blood Parasite Infection Differentially Relates to Carotenoid-Based Plumage and Bill Color in the American Goldfinch

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    Male and female American goldfinches (Spinus tristis) express condition-dependent carotenoid-based plumage and bill coloration. Plumage color is relatively static, as pigments incorporated into feathers during the spring molt cannot be mobilized thereafter. In contrast, bill color is dynamic, reflecting changes in condition over short time periods. Previous studies have shown that male and female ornaments, though similar in expression, are differentially related to measures of immunocompetence, suggesting that the relationship between ornamentation and parasite infection may differ between the sexes. In this study, we evaluate the relationship between condition-dependent ornamentation (plumage and bill color) and blood parasite infection in male and female American goldfinches. We captured goldfinches after completion of the pre-alternate molt and prior to the onset of nesting and assessed prevalence of Trypanosoma parasites via blood smears. Plumage color strongly predicted trypanosome infection: Birds with more colorful plumage were less likely to present infections. In contrast, we detected no relationship between infection and bill color, which in other studies has been shown to dynamically reflect current condition. Sex did not affect the relationship between infection status and either ornament. Together, these results suggest that physiological pathways linking carotenoid ornamentation and infection may vary even within a single species

    A growing disconnection from nature is evident in cultural products

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    Human connection with nature is widely believed to be in decline, even though empirical evidence on the magnitude and temporal pattern of the change is scarce. Studying works of popular culture in English throughout the 20th century and later, we document a cultural shift away from nature, beginning in the 1950s. Since then, references to nature have been decreasing steadily in fiction, song lyrics, and film storylines. No parallel decline is observed in references to the human-made environment. These findings are cause for concern, not only because they imply foregone benefits from engagement with nature, but also because cultural products are agents of socialization that can evoke curiosity, respect, and concern for the natural world

    Thermal detection of single e-h pairs in a biased silicon crystal detector

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    We demonstrate that individual electron-hole pairs are resolved in a 1 cm2^2 by 4 mm thick silicon crystal (0.93 g) operated at \sim35 mK. One side of the detector is patterned with two quasiparticle-trap-assisted electro-thermal-feedback transition edge sensor (QET) arrays held near ground potential. The other side contains a bias grid with 20\% coverage. Bias potentials up to ±\pm 160 V were used in the work reported here. A fiber optic provides 650~nm (1.9 eV) photons that each produce an electron-hole (eh+e^{-} h^{+}) pair in the crystal near the grid. The energy of the drifting charges is measured with a phonon sensor noise σ\sigma \sim0.09 eh+e^{-} h^{+} pair. The observed charge quantization is nearly identical for h+h^+'s or ee^-'s transported across the crystal.Comment: 4 journal pages, 5 figure

    Evolution of breeding plumages in birds: A multiple-step pathway to seasonal dichromatism in New World warblers (Aves: Parulidae)

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    Ecology and Evolution published by John Wiley & Sons Ltd Many species of birds show distinctive seasonal breeding and nonbreeding plumages. A number of hypotheses have been proposed for the evolution of this seasonal dichromatism, specifically related to the idea that birds may experience variable levels of sexual selection relative to natural selection throughout the year. However, these hypotheses have not addressed the selective forces that have shaped molt, the underlying mechanism of plumage change. Here, we examined relationships between life-history variation, the evolution of a seasonal molt, and seasonal plumage dichromatism in the New World warblers (Aves: Parulidae), a family with a remarkable diversity of plumage, molt, and life-history strategies. We used phylogenetic comparative methods and path analysis to understand how and why distinctive breeding and nonbreeding plumages evolve in this family. We found that color change alone poorly explains the evolution of patterns of biannual molt evolution in warblers. Instead, molt evolution is better explained by a combination of other life-history factors, especially migration distance and foraging stratum. We found that the evolution of biannual molt and seasonal dichromatism is decoupled, with a biannual molt appearing earlier on the tree, more dispersed across taxa and body regions, and correlating with separate life-history factors than seasonal dichromatism. This result helps explain the apparent paradox of birds that molt biannually but show breeding plumages that are identical to the nonbreeding plumage. We find support for a two-step process for the evolution of distinctive breeding and nonbreeding plumages: That prealternate molt evolves primarily under selection for feather renewal, with seasonal color change sometimes following later. These results reveal how life-history strategies and a birds\u27 environment act upon multiple and separate feather functions to drive the evolution of feather replacement patterns and bird coloration

    Novel HSPB1 mutation causes both motor neuronopathy and distal myopathy.

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    OBJECTIVE: To identify the cause of isolated distal weakness in a family with both neuropathic and myopathic features on EMG and muscle histology. METHODS: Case study with exome sequencing in 2 affected individuals, bioinformatic prioritization of genetic variants, and segregation analysis of the likely causal mutation. Functional studies included Western blot analysis of the candidate protein before and after heat shock treatment of primary skin fibroblasts. RESULTS: A novel HSPB1 variant (c.387C>G, p.Asp129Glu) segregated with the phenotype and was predicted to alter the conserved α-crystallin domain common to small heat shock proteins. At baseline, there was no difference in HSPB1 protein levels nor its binding partner αB-crystallin. Heat shock treatment increased HSPB1 protein levels in both patient-derived and control fibroblasts, but the associated increase in αB-crystallin expression was greater in patient-derived than control fibroblasts. CONCLUSIONS: The HSPB1 variant (c.387C>G, p.Asp129Glu) is the likely cause of distal neuromyopathy in this pedigree with pathogenic effects mediated through binding to its partner heat shock protein αB-crystallin. Mutations in HSBP1 classically cause a motor axonopathy, but this family shows that the distal weakness can be both myopathic and neuropathic. The traditional clinical classification of distal weakness into "myopathic" or "neuropathic" forms may be misleading in some instances, and future treatments need to address the pathology in both tissues.This study was funded by Wellcome Trust (101876/Z/13/Z and 096919Z/11/Z), Medical Research Council (UK) (G0601943), and Medical Research Council Mitochondrial Biology Unit (MC_UP_1501/2). Funding bodies had no influence on study design or data interpretation.This is the final version of the article. It first appeared from Wolters Kluwer via http://dx.doi.org/10.1212/NXG.000000000000011

    Data mining: a tool for detecting cyclical disturbances in supply networks.

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    Disturbances in supply chains may be either exogenous or endogenous. The ability automatically to detect, diagnose, and distinguish between the causes of disturbances is of prime importance to decision makers in order to avoid uncertainty. The spectral principal component analysis (SPCA) technique has been utilized to distinguish between real and rogue disturbances in a steel supply network. The data set used was collected from four different business units in the network and consists of 43 variables; each is described by 72 data points. The present paper will utilize the same data set to test an alternative approach to SPCA in detecting the disturbances. The new approach employs statistical data pre-processing, clustering, and classification learning techniques to analyse the supply network data. In particular, the incremental k-means clustering and the RULES-6 classification rule-learning algorithms, developed by the present authors’ team, have been applied to identify important patterns in the data set. Results show that the proposed approach has the capability automatically to detect and characterize network-wide cyclical disturbances and generate hypotheses about their root cause

    Ozone loss derived from balloon-borne tracer measurements in the 1999/2000 Arctic winter

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    Balloon-borne measurements of CFC11 (from the DIRAC in situ gas chromatograph and the DESCARTES grab sampler), ClO and O3 were made during the 1999/2000 Arctic winter as part of the SOLVE-THESEO 2000 campaign, based in Kiruna (Sweden). Here we present the CFC11 data from nine flights and compare them first with data from other instruments which flew during the campaign and then with the vertical distributions calculated by the SLIMCAT 3D CTM. We calculate ozone loss inside the Arctic vortex between late January and early March using the relation between CFC11 and O3 measured on the flights. The peak ozone loss (~1200ppbv) occurs in the 440-470K region in early March in reasonable agreement with other published empirical estimates. There is also a good agreement between ozone losses derived from three balloon tracer data sets used here. The magnitude and vertical distribution of the loss derived from the measurements is in good agreement with the loss calculated from SLIMCAT over Kiruna for the same days

    A satellite chronology of plumes from the April 2021 eruption of La Soufrière, St Vincent

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    Satellite instruments play a valuable role in detecting, monitoring and characterising emissions of ash and gas into the atmosphere during volcanic eruptions. This study uses two satellite instruments, the Infrared Atmospheric Sounding Interferometer (IASI) and the Advanced Baseline Imager (ABI), to examine the plumes of ash and sulfur dioxide (SO2) from the April 2021 eruption of La Soufrière, St Vincent. The frequent ABI data have been used to construct a 14 d chronology of a series of explosive events at La Soufrière, which is then complemented by measurements of SO2 from IASI, which is able to track the plume as it is transported around the globe. A minimum of 35 eruptive events were identified using true, false and brightness temperature difference maps produced with the ABI data. The high temporal resolution images were used to identify the approximate start and end times, as well as the duration and characteristics of each event. From this analysis, four distinct phases within the 14 d eruption have been defined, each consisting of multiple explosive events with similar characteristics: (1) an initial explosive event, (2) a sustained event lasting over 9 h, (3) a pulsatory phase with 25 explosive events in a 65.3 h period and (4) a waning sequence of explosive events. It is likely that the multiple explosive events during the April 2021 eruption contributed to the highly complex plume structure that can be seen in the IASI measurements of the SO2 column amounts and heights. The bulk of the SO2 from the first three phases of the eruption was transported eastwards, which based on the wind direction at the volcano implies that the SO2 was largely in the upper troposphere. Some of the SO2 was carried to the south and west of the volcano, suggesting a smaller emission of the gas into the stratosphere, there being a shift in wind direction around the height of the tropopause. The retrieved SO2 heights show that the plume had multiple layers but was largely concentrated between 13 and 19 km, with the majority of the SO2 being located in the upper troposphere and around the height of the tropopause, with some emission into the stratosphere. An average e-folding time of 6.07±4.74 d was computed based on the IASI SO2 results: similar to other tropical eruptions of this magnitude and height. The SO2 was trackable for several weeks after the eruption and is shown to have circulated the globe, with parts of it reaching as far as 45∘ S and 45∘ N. Using the IASI SO2 measurements, a time series of the total SO2 mass loading was produced, with this peaking on 13 April (descending orbits) at 0.31±0.09 Tg. Converting these mass values to a temporally varying SO2 flux demonstrated that the greatest emission occurred on 10 April with that measurement incorporating SO2 from the second phase of the eruption (sustained emission) and the beginning of the pulsatory phase. The SO2 flux is then shown to fall during the later stages of the eruption: suggesting a reduction in eruptive energy, something also reflected in ash height estimates obtained with the ABI instrument. A total SO2 emission of 0.63±0.5 Tg of SO2 has been derived, although due to limitations associated with the retrieval, particularly in the first few days after the eruption began, this, the retrieved column amounts and the total SO2 mass on each day should be considered minimum estimates. There are a number of similarities between the 1979 and 2021 eruptions at La Soufrière, with both eruptions consisting of a series of explosive events with varied heights and including some emission into the stratosphere. These similarities highlight the importance of in-depth investigations into eruptions and the valuable contribution of satellite data for this purpose; as these studies aid in learning about a volcano's behaviour, which may allow for better preparation for future eruptive activity

    Methane Mitigation:Methods to Reduce Emissions, on the Path to the Paris Agreement

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    The atmospheric methane burden is increasing rapidly, contrary to pathways compatible with the goals of the 2015 United Nations Framework Convention on Climate Change Paris Agreement. Urgent action is required to bring methane back to a pathway more in line with the Paris goals. Emission reduction from “tractable” (easier to mitigate) anthropogenic sources such as the fossil fuel industries and landfills is being much facilitated by technical advances in the past decade, which have radically improved our ability to locate, identify, quantify, and reduce emissions. Measures to reduce emissions from “intractable” (harder to mitigate) anthropogenic sources such as agriculture and biomass burning have received less attention and are also becoming more feasible, including removal from elevated-methane ambient air near to sources. The wider effort to use microbiological and dietary intervention to reduce emissions from cattle (and humans) is not addressed in detail in this essentially geophysical review. Though they cannot replace the need to reach “net-zero” emissions of CO2, significant reductions in the methane burden will ease the timescales needed to reach required CO2 reduction targets for any particular future temperature limit. There is no single magic bullet, but implementation of a wide array of mitigation and emission reduction strategies could substantially cut the global methane burden, at a cost that is relatively low compared to the parallel and necessary measures to reduce CO2, and thereby reduce the atmospheric methane burden back toward pathways consistent with the goals of the Paris Agreement

    Frequency of rare recessive mutations in unexplained late onset cerebellar ataxia.

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    Sporadic late onset cerebellar ataxia is a well-described clinical presentation with a broad differential diagnosis that adult neurologists should be familiar with. However, despite extensive clinical investigations, an acquired cause is identified in only a minority of cases. Thereafter, an underlying genetic basis is often considered, even in those without a family history. Here we apply whole exome sequencing to a cohort of 12 patients with late onset cerebellar ataxia. We show that 33% of 'idiopathic' cases harbor compound heterozygous mutations in known ataxia genes, including genes not included on multi-gene panels, or primarily associated with an ataxic presentation
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