345 research outputs found
Optical coherence elastography based on inverse compositional Gauss-Newton digital volume correlation with second-order shape function
A digital volume correlation (DVC)-based optical coherence elastography (OCE) method with inverse compositional Gauss-Newton (IC-GN) algorithm and second-order shape function is presented in this study. The systematic measurement errors of displacement and strain from our OCE method were less than 0.2 voxel and 4âĂâ10â4, respectively. Second-order shape function could better match complex deformation and decrease speckle rigidity-induced error. Compared to conventional methods, our OCE method could track a larger strain range up to 0.095 and reduce relative error by 30-50%. This OCE method has the potential to become an effective tool in characterising mechanical properties of biological tissue
Controlling an Invasive Forest Pest, the Asiatic Oak Weevil (cyrtepistomus castaneus), Using Prescribed Fire
Invasive species are non-native species whose presence is already or is likely to cause harm to the local ecosystem or economy, or human, animal, and plant health (Beck et al, 2006, p.415). The invasive Asiatic oak weevil is the primary leaf-feeding insect on oak trees in the Missouri Ozarks with larvae feeding on the roots of trees and the adults on the leaves (Marquis and Bhatti-Catano, 2017). The goal of this study was to determine if prescribed burns lower the abundance of adult and larval weevils. Eight pairs of 200 m x 200 m plots in the oak-hickory forest at the Tyson Research Station near Eureka, MO were used for the experimental environment. One of each plot pairs were surface-burned in early Spring 2018. In June 2018, mesh emergence traps with jars secured on top were placed under four white and four black oak trees on each plot. From late June-August 2018 the weevils were counted as they emerged and analyzed to determine effects of the sampling date, tree species, aspect, slope, weight, and ultimately weevil density in burned versus unburned plots. Notable differences in the density of weevils on burned vs. unburned plots were observed in favor of the hypothesis. These findings support the need for prescribed fire in the management of Missouriâs forests. References Beck, G. K. Zimmerman, J.D. Schardt, J. Stone, R.R. Lukens, S. Reichard, J. Randall, A.A. Cangelosi, D. Cooper, and J.P. Thompson. 2006. Invasive Species Defined in a Policy Context: Recommendations from the Federal Invasive Species Advisory Committee. Invasive Plant Science and Management 1(4):414-421. Marquis, R. J., & Bhatti-Catano, L. (2017). Impacts of the Asiatic oak weevil (Cyrtepistomus castaneus) on the growth and survivorship of black oak (Quercus velutina) seedlings. Retrieved February 10, 2019, from https://tyson.wustl.edu/allprojects/2017/10/4/impacts of-the-asiatic-oak-weevil-icyrtepistomus-castaneusi-on-the-growth-and-survivorship-of black-oak-iquercus-velutinai-seedling
Integrating species traits into species pools
Despite decades of research on the speciesâpool concept and the recent explosion of interest in traitâbased frameworks in ecology and biogeography, surprisingly little is known about how spatial and temporal changes in speciesâpool functional diversity (SPFD) influence biodiversity and the processes underlying community assembly. Current traitâbased frameworks focus primarily on community assembly from a static regional species pool, without considering how spatial or temporal variation in SPFD alters the relative importance of deterministic and stochastic assembly processes. Likewise, speciesâpool concepts primarily focus on how the number of species in the species pool influences local biodiversity. However, species pools with similar richness can vary substantially in functionalâtrait diversity, which can strongly influence community assembly and biodiversity responses to environmental change. Here, we integrate recent advances in community ecology, traitâbased ecology, and biogeography to provide a more comprehensive framework that explicitly considers how variation in SPFD, among regions and within regions through time, influences the relative importance of community assembly processes and patterns of biodiversity. First, we provide a brief overview of the primary ecological and evolutionary processes that create differences in SPFD among regions and within regions through time. We then illustrate how SPFD may influence fundamental processes of local community assembly (dispersal, ecological drift, niche selection). Higher SPFD may increase the relative importance of deterministic community assembly when greater functional diversity in the species pool increases niche selection across environmental gradients. In contrast, lower SPFD may increase the relative importance of stochastic community assembly when high functional redundancy in the species pool increases the influence of dispersal history or ecological drift. Next, we outline experimental and observational approaches for testing the influence of SPFD on assembly processes and biodiversity. Finally, we highlight applications of this framework for restoration and conservation. This speciesâpool functional diversity framework has the potential to advance our understanding of how localâ and regionalâscale processes jointly influence patterns of biodiversity across biogeographic regions, changes in biodiversity within regions over time, and restoration outcomes and conservation efforts in ecosystems altered by environmental change
Impact of cyclic bending on coronary hemodynamics
It remains unknown that the degree of bias in computational fluid dynamics results without considering coronary cyclic bending. This study aims to investigate the influence of different rates of coronary cyclic bending on coronary hemodynamics. To model coronary bending, a multi-ring-controlled fluidâstructural interaction model was designed. A coronary artery was simulated with various cyclic bending rates (0.5, 0.75 and 1 s, corresponding to heart rates of 120, 80 and 60 bpm) and compared against a stable model. The simulated results show that the hemodynamic parameters of vortex Q-criterion, temporal wall shear stress (WSS), time-averaged WSS (TaWSS) and oscillatory shear index (OSI) were sensitive to the changes in cyclic rate. A higher heart rate resulted in higher magnitude and larger variance in the hemodynamic parameters. Whereas, the values and distributions of flow velocity and relative residence time (RRT) did not show significant differences between different bending periods. This study suggests that a stable coronary model is not sufficient to represent the hemodynamics in a bending coronary artery. Different heart rate conditions were found to have significant impact on the hemodynamic parameters. Thus, cyclic bending should be considered to mimic the realistic hemodynamics in future patient-specific coronary hemodynamics studies
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First measurement of neutrino oscillation parameters using neutrinos and antineutrinos by NOvA.
The NOvA experiment has seen a 4.4Ď signal of ν[over ÂŻ]_{e} appearance in a 2 GeV ν[over ÂŻ]_{Îź} beam at a distance of 810 km. Using 12.33Ă10^{20} protons on target delivered to the Fermilab NuMI neutrino beamline, the experiment recorded 27 ν[over ÂŻ]_{Îź}âν[over ÂŻ]_{e} candidates with a background of 10.3 and 102 ν[over ÂŻ]_{Îź}âν[over ÂŻ]_{Îź} candidates. This new antineutrino data are combined with neutrino data to measure the parameters |Îm_{32}^{2}|=2.48_{-0.06}^{+0.11}Ă10^{-3}ââeV^{2}/c^{4} and sin^{2}θ_{23} in the ranges from (0.53-0.60) and (0.45-0.48) in the normal neutrino mass hierarchy. The data exclude most values near δ_{CP}=Ď/2 for the inverted mass hierarchy by more than 3Ď and favor the normal neutrino mass hierarchy by 1.9Ď and θ_{23} values in the upper octant by 1.6Ď
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Observation of seasonal variation of atmospheric multiple-muon events in the NOvA Near Detector
Using two years of data from the NOvA Near Detector at Fermilab, we report a seasonal variation of cosmic ray induced multiple-muon (NÎźâĽ2) event rates which has an opposite phase to the seasonal variation in the atmospheric temperature. The strength of the seasonal multiple-muon variation is shown to increase as a function of the muon multiplicity. However, no significant dependence of the strength of the seasonal variation of the multiple-muon variation is seen as a function of the muon zenith angle, or the spatial or angular separation between the correlated muons
The Search for Host Genetic Factors of HIV/AIDS Pathogenesis in the Post-Genome Era: Progress to Date and New Avenues for Discovery
Though pursuit of host genetic factors that influence the pathogenesis of HIV began over two decades ago, progress has been slow. Initial genome-level searches for variations associated with HIV-related traits have yielded interesting candidates, but less in the way of novel pathways to be exploited for therapeutic targets. More recent genome-wide association studies (GWAS) that include different phenotypes, novel designs, and that have examined different population characteristics suggest novel targets and affirm the utility of additional searches. Recent findings from these GWAS are reviewed, new directions for research are identified, and the promise of systems biology to yield novel insights is discussed
Letter of Intent: The Accelerator Neutrino Neutron Interaction Experiment (ANNIE)
Neutron tagging in Gadolinium-doped water may play a significant role in reducing backgrounds from atmospheric neutrinos in next generation proton-decay searches using megaton-scale Water Cherenkov detectors. Similar techniques might also be useful in the detection of supernova neutrinos. Accurate determination of neutron tagging efficiencies will require a detailed understanding of the number of neutrons produced by neutrino interactions in water as a function of momentum transferred. We propose the Atmospheric Neutrino Neutron Interaction Experiment (ANNIE), designed to measure the neutron yield of atmospheric neutrino interactions in gadolinium-doped water. An innovative aspect of the ANNIE design is the use of precision timing to localize interaction vertices in the small fiducial volume of the detector. We propose to achieve this by using early production of LAPPDs (Large Area Picosecond Photodetectors). This experiment will be a first application of these devices demonstrating their feasibility for Water Cherenkov neutrino detectors
DSSylation, a novel protein modification targets proteins induced by oxidative stress, and facilitates their degradation in cells
Timely removal of oxidatively damaged proteins is critical for cells exposed to oxidative stresses; however, cellular mechanism for clearing oxidized proteins is not clear. Our study reveals a novel type of protein modification that may play a role in targeting oxidized proteins and remove them. In this process, DSS1 (deleted in split hand/split foot 1), an evolutionally conserved small protein, is conjugated to proteins induced by oxidative stresses in vitro and in vivo, implying oxidized proteins are DSS1 clients. A subsequent ubiquitination targeting DSS1-protein adducts has been observed, suggesting the client proteins are degraded through the ubiquitin-proteasome pathway. The DSS1 attachment to its clients is evidenced to be an enzymatic process modulated by an unidentified ATPase. We name this novel protein modification as DSSylation, in which DSS1 plays as a modifier, whose attachment may render target proteins a signature leading to their subsequent ubiquitination, thereby recruits proteasome to degrade them.Electronic supplementary materialThe online version of this article (doi:10.1007/s13238-013-0018-8) contains supplementary material, which is available to authorized users
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