57 research outputs found

    Predicting the population viability of an endangered amphibian under environmental and demographic uncertainty

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    Population viability analyses (PVAs) represent a key component of many recovery plans for threatened and endangered species. Demography links the processes that affect individuals to population-level patterns, and hence projections constructed from demographic data are the most common tools for PVAs. We constructed a size-structured integral projection model (IPM) for the United States federally endangered Reticulated Flatwoods Salamander, Ambystoma bishopi, to evaluate demographic influences on population growth and predict the efficacy of future management actions. Flatwoods salamanders breed in ephemeral wetlands in the Southeastern United States. The ephemeral nature of breeding sites can result in complete recruitment failure in drought years when wetlands fail to fill, or dry before metamorphosis occurs. As a result, this species exhibits marked temporal variability in vital rates that must be accounted for in projection models. We constructed a stochastic IPM using 13 years of mark-recapture data (2010–2023) from two breeding wetlands. Variable survival rates exhibited by flatwoods salamanders, coupled with a high probability of recruitment failure, result in a low predicted probability of population persistence. Sensitivity analyses revealed age at maturity and the frequency of recruitment exerted the greatest influence on population growth, and thus managers should prioritize conservation efforts that target these demographic processes. Additional management should consider strategies to dampen temporal variability in larval survival, something that could be achieved through emergency salvage operations, captive rearing efforts, and manipulation of wetland hydroperiods

    Lepton flavor violation decays τ−→Ό−P1P2\tau^-\to \mu^- P_1 P_2 in the topcolor-assisted technicolor model and the littlest Higgs model with TT parity

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    The new particles predicted by the topcolor-assisted technicolor (TC2TC2) model and the littlest Higgs model with T-parity (called LHTLHT model) can induce the lepton flavor violation (LFVLFV) couplings at tree level or one loop level, which might generate large contributions to some LFVLFV processes. Taking into account the constraints of the experimental data on the relevant free parameters, we calculate the branching ratios of the LFVLFV decay processes τ−→Ό−P1P2\tau^-\to\mu^- P_1 P_2 with P1P2P_1 P_2 = π+π−\pi^+\pi^-, K+K−K^+K^- and K0K0ˉK^0\bar{K^0} in the context of these two kinds of new physics models. We find that the TC2TC2 model and the LHTLHT model can indeed produce significant contributions to some of these LFVLFV decay processes.Comment: 24 pages, 7 figure

    3D Coronal Density Reconstruction and Retrieving the Magnetic Field Structure during Solar Minimum

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    Measurement of the coronal magnetic field is a crucial ingredient in understanding the nature of solar coronal phenomena at all scales. We employed STEREO/COR1 data obtained during a deep minimum of solar activity in February 2008 (Carrington rotation CR 2066) to retrieve and analyze the three-dimensional (3D) coronal electron density in the range of heights from 1.5 to 4 Rsun using a tomography method. With this, we qualitatively deduced structures of the coronal magnetic field. The 3D electron density analysis is complemented by the 3D STEREO/EUVI emissivity in the 195 A band obtained by tomography for the same CR. A global 3D MHD model of the solar corona was used to relate the reconstructed 3D density and emissivity to open/closed magnetic field structures. We show that the density maximum locations can serve as an indicator of current sheet position, while the locations of the density gradient maximum can be a reliable indicator of coronal hole boundaries. We find that the magnetic field configuration during CR 2066 has a tendency to become radially open at heliocentric distances greater than 2.5 Rsun. We also find that the potential field model with a fixed source surface (PFSS) is inconsistent with the boundaries between the regions with open and closed magnetic field structures. This indicates that the assumption of the potential nature of the coronal global magnetic field is not satisfied even during the deep solar minimum. Results of our 3D density reconstruction will help to constrain solar coronal field models and test the accuracy of the magnetic field approximations for coronal modeling.Comment: Published in "Solar Physics

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

    Influence of annealing on recrystallization and mechanical properties of Zr702 alloy obtained by accumulative roll bonding

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    The influence of annealing time on the recrystallization evolution and mechanical behavior of Zr702 alloy obtained by accumulative roll bonding (ARB) has been investigated. Results show that the bonding degree of the ARB interface gradually improved with the increase of annealing time from 5 to 20 min, which is because the atoms can obtain relatively more diffusion driving force with the increase of annealing time. In addition, almost complete recrystallization (average size of about 3.98 Όm) and excellent comprehensive mechanical properties can be obtained as the annealing time is set to 20 min, and the evolution path of the microstructure with annealing time can be described as: (I) high density stacking dislocations; (II) formation of subgrain boundaries; (III) reduction of dislocation density and formation of recrystallization; (IV) growth of recrystallized grains. In this study, with the increase of annealing time, the release of deformation storage energy and the increase of recrystallized dislocation-free grains are very helpful to improve the ductility

    Evolutionary History and Ongoing Transmission of Phylogenetic Sublineages of Mycobacterium tuberculosis Beijing Genotype in China.

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    &lt;p&gt;Mycobacterium tuberculosis Beijing genotype originated in China and has undergone a dramatic population growth and global spread in the last century. Here, a collection of M. tuberculosis Beijing family isolates from different provinces across all China was genotyped by high-resolution (24-MIRU-VNTR) and low-resolution, high-rank (modern and ancient sublineages) markers. The molecular profiles and global and local phylogenies were compared to the strain phenotype and patient data. The phylogeographic patterns observed in the studied collection demonstrate that large-scale (but not middle/small-scale) distance remains one of the decisive factors of the genetic divergence of M. tuberculosis populations. Analysis of diversity and network topology of the local collections appears to corroborate a recent intriguing hypothesis about Beijing genotype originating in South China. Placing our results within the Eurasian context suggested that important Russian B0/W148 and Asian/Russian A0/94-32 epidemic clones of the Beijing genotype could trace their origins to the northeastern and northwestern regions of China, respectively. The higher clustering of the modern isolates in children and lack of increased MDR rate in any sublineage suggest that not association with drug resistance but other (e.g., speculatively, virulence-related) properties underlie an enhanced dissemination of the evolutionarily recent, modern sublineage of the Beijing genotype in China.&lt;/p&gt;</p

    Data from: The cover uncovered: bark control over wood decomposition

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    1. Woody debris (WD) represents a globally significant carbon stock and its decomposition returns nutrients to the soil while providing habitat to microbes, plants and animals. Understanding what drives WD decomposition is therefore important. 2. WD decomposition rates differ greatly among species. However, the role of bark in the process remains poorly known. 3. We ask how, and how much, interspecific variation in bark functional traits related to growth and protection have afterlife effects on the decomposition of wood, partly mediated by animals. We examine the roles of bark cover and bark traits throughout the wood decomposition process. 4. Synthesis. We find that: (i) bark effects on WD decomposition are species- and wood size-specific, (ii) bark can enhance coarser WD decomposition but slows twig decomposition in some species, and (iii) bark acts as an environmental filter to faunal assemblages in the early stage of wood decomposition. We highlight the need to account for bark effects on WD decomposition and offer an important complementary contribution to including woody species identity effects in biogeochemical and climate-change models via species bark traits

    The cover uncovered:Bark control over wood decomposition

    No full text
    Woody debris (WD) represents a globally significant carbon stock and its decomposition returns nutrients to the soil while providing habitat to microbes, plants and animals. Understanding what drives WD decomposition is therefore important. WD decomposition rates differ greatly among species. However, the role of bark in the process remains poorly known. We ask how, and how much, interspecific variation in bark functional traits related to growth and protection have afterlife effects on the decomposition of wood, partly mediated by animals. We examine the roles of bark cover and bark traits throughout the wood decomposition process. Synthesis. We find that: (1) bark effects on WD decomposition are species- and wood size-specific, (2) bark can enhance coarser WD decomposition but slows twig decomposition in some species, and (3) bark acts as an environmental filter to faunal assemblages in the early stage of wood decomposition. We highlight the need to account for bark effects on WD decomposition and offer an important complementary contribution to including woody species identity effects in biogeochemical and climate-change models via species bark traits
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