426 research outputs found

    Separable and non-separable multi-field inflation and large non-Gaussianity

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    In this paper we provide a general framework based on δN\delta N formalism to estimate the cosmological observables pertaining to the cosmic microwave background radiation for non-separable potentials, and for generic \emph{end of inflation} boundary conditions. We provide analytical and numerical solutions to the relevant observables by decomposing the cosmological perturbations along the curvature and the isocurvature directions, \emph{instead of adiabatic and entropy directions}. We then study under what conditions large bi-spectrum and tri-spectrum can be generated through phase transition which ends inflation. In an illustrative example, we show that large fNLO(80)f_{NL}\sim {\cal O}(80) and τNLO(20000)\tau_{NL}\sim {\cal O}(20000) can be obtained for the case of separable and non-separable inflationary potentials.Comment: 21 pages, 6 figure

    Dry period plane of energy: Effects on glucose tolerance in transition dairy cows

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    Overfeeding energy in the dry period can affect glucose metabolism and the energy balance of transition dairy cows with potential detrimental effects on the ability to successfully adapt to early lactation. The objectives of this study were to investigate the effect of different dry cow feeding strategies on glucose tolerance and on resting concentrations of blood glucose, glucagon, insulin, nonesterified fatty acids (NEFA), and β-hydroxybutyrate (BHB) in the peripartum period. Cows entering second or greater lactation were enrolled at dry-off (57 d before expected parturition) into 1 of 3 treatment groups following a randomized block design: cows that received a total mixed ration (TMR) formulated to meet but not exceed energy requirements during the dry period (n = 28, controlled energy); cows that received a TMR supplying approximately 150% of energy requirements during the dry period (n = 28, high energy); and cows that were fed the same diet as the controlled energy group for the first 28 d, after which the TMR was formulated to supply approximately 125% of energy requirements until calving (n = 28, intermediate energy). Intravenous glucose tolerance tests (IVGTT) with rapid administration of 0.25 g of glucose/kg of body weight were performed 28 and 10 d before expected parturition, as well as at 4 and 21 d after calving. Area under the curve for insulin and glucose, maximal concentration and time to half-maximal concentration of insulin and glucose, and clearance rates were calculated. Insulin resistance (IR) indices were calculated from baseline samples obtained during IVGTT and Spearman rank correlations determined between IVGTT parameters and IR indices. Treatment did not affect IVGTT parameters at any of the 4 time points. Correlation between IR indices and IVGTT parameters was generally poor. Overfeeding cows energy in excess of predicted requirements by approximately 50% during the entire dry period resulted in decreased postpartum basal plasma glucose and insulin, as well as increased glucagon, BHB, and NEFA concentrations after calving compared with cows fed a controlled energy diet during the dry period. In conclusion, overfeeding energy during the entire dry period or close-up period alone did not affect glucose tolerance as assessed by IVGTT but energy uptake during the dry period was associated with changes in peripartal resting concentrations of glucose, as well as postpartum insulin, glucagon, NEFA, and BHB concentrations

    Winter soil respiration in a humid temperate forest: The roles of moisture, temperature, and snowpack

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    Winter soil respiration at midlatitudes can comprise a substantial portion of annual ecosystem carbon loss. However, winter soil carbon dynamics in these areas, which are often characterized by shallow snow cover, are poorly understood due to infrequent sampling at the soil surface. Our objectives were to continuously measure winter CO2 flux from soils and the overlying snowpack while also monitoring drivers of winter soil respiration in a humid temperate forest. We show that the relative roles of soil temperature and moisture in driving winter CO2 flux differed within a single soil-to-snow profile. Surface soil temperatures had a strong, positive influence on CO2 flux from the snowpack, while soil moisture exerted a negative control on soil CO2 flux within the soil profile. Rapid fluctuations in snow depth throughout the winter likely created the dynamic soil temperature and moisture conditions that drove divergent patterns in soil respiration at different depths. Such dynamic conditions differ from many previous studies of winter soil microclimate and respiration, where soil temperature and moisture are relatively stable until snowmelt. The differential response of soil respiration to temperature and moisture across depths was also a unique finding as previous work has not simultaneously quantified CO2 flux from soils and the snowpack. The complex interplay we observed among snow depth, soil temperature, soil moisture, and CO2 flux suggests that winter soil respiration in areas with shallow seasonal snow cover is more variable than previously understood and may fluctuate considerably in the future given winter climate change

    Lower extremity joint kinetics and lumbar curvature during squat and stoop lifting

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    <p>Abstract</p> <p>Background</p> <p>In this study, kinematics and kinetics of the lower extremity joint and the lumbar lordosis during two different symmetrical lifting techniques(squat and stoop) were examined using the three-dimensional motion analysis.</p> <p>Methods</p> <p>Twenty-six young male volunteers were selected for the subjects in this study. While they lifted boxes weighing 5, 10 and 15 kg by both squat and stoop lifting techniques, their motions were captured and analyzed using the 3D motion analysis system which was synchronized with two forceplates and the electromyographic system. Joint kinematics was determined by the forty-three reflective markers which were attached on the anatomical locations based on the VICON Plug-in-Gait marker placement protocol. Joint kinetics was analyzed by using the inverse dynamics. Paired t-test and Kruskal-Wallis test was used to compare the differences of variables between two techniques, and among three different weights. Correlation coefficient was calculated to explain the role of lower limb joint motion in relation to the lumbar lordosis.</p> <p>Results</p> <p>There were not significant differences in maximum lumbar joint moments between two techniques. The hip and ankle contributed the most part of the support moment during squat lifting, and the knee flexion moment played an important role in stoop lifting. The hip, ankle and lumbar joints generated power and only the knee joint absorbed power in the squat lifting. The knee and ankle joints absorbed power, the hip and lumbar joints generated power in the stoop lifting. The bi-articular antagonist muscles' co-contraction around the knee joint during the squat lifting and the eccentric co-contraction of the gastrocnemius and the biceps femoris were found important for maintaining the straight leg during the stoop lifting. At the time of lordotic curvature appearance in the squat lifting, there were significant correlations in all three lower extremity joint moments with the lumbar joint. Differently, only the hip moment had significant correlation with the lumbar joint in the stoop lifting.</p> <p>Conclusion</p> <p>In conclusion, the knee extension which is prominent kinematics during the squat lifting was produced by the contributions of the kinetic factors from the hip and ankle joints(extensor moment and power generation) and the lumbar extension which is prominent kinematics during the stoop lifting could be produced by the contributions of the knee joint kinetic factors(flexor moment, power absorption, bi-articular muscle function).</p

    Heterologous expression screens in Nicotiana benthamiana identify a candidate effector of the wheat Yellow Rust Pathogen that associates with processing bodies

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    Rust fungal pathogens of wheat (Triticum spp.) affect crop yields worldwide. The molecular mechanisms underlying the virulence of these pathogens remain elusive, due to the limited availability of suitable molecular genetic research tools. Notably, the inability to perform high-throughput analyses of candidate virulence proteins (also known as effectors) impairs progress. We previously established a pipeline for the fast-forward screens of rust fungal candidate effectors in the model plant Nicotiana benthamiana. This pipeline involves selecting candidate effectors in silico and performing cell biology and protein-protein interaction assays in planta to gain insight into the putative functions of candidate effectors. In this study, we used this pipeline to identify and characterize sixteen candidate effectors from the wheat yellow rust fungal pathogen Puccinia striiformis f sp tritici. Nine candidate effectors targeted a specific plant subcellular compartment or protein complex, providing valuable information on their putative functions in plant cells. One candidate effector, PST02549, accumulated in processing bodies (P-bodies), protein complexes involved in mRNA decapping, degradation, and storage. PST02549 also associates with the P-body-resident ENHANCER OF mRNA DECAPPING PROTEIN 4 (EDC4) from N. benthamiana and wheat. We propose that P-bodies are a novel plant cell compartment targeted by pathogen effectors

    Lower extremity joint kinetics and lumbar curvature during squat and stoop lifting

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    <p>Abstract</p> <p>Background</p> <p>In this study, kinematics and kinetics of the lower extremity joint and the lumbar lordosis during two different symmetrical lifting techniques(squat and stoop) were examined using the three-dimensional motion analysis.</p> <p>Methods</p> <p>Twenty-six young male volunteers were selected for the subjects in this study. While they lifted boxes weighing 5, 10 and 15 kg by both squat and stoop lifting techniques, their motions were captured and analyzed using the 3D motion analysis system which was synchronized with two forceplates and the electromyographic system. Joint kinematics was determined by the forty-three reflective markers which were attached on the anatomical locations based on the VICON Plug-in-Gait marker placement protocol. Joint kinetics was analyzed by using the inverse dynamics. Paired t-test and Kruskal-Wallis test was used to compare the differences of variables between two techniques, and among three different weights. Correlation coefficient was calculated to explain the role of lower limb joint motion in relation to the lumbar lordosis.</p> <p>Results</p> <p>There were not significant differences in maximum lumbar joint moments between two techniques. The hip and ankle contributed the most part of the support moment during squat lifting, and the knee flexion moment played an important role in stoop lifting. The hip, ankle and lumbar joints generated power and only the knee joint absorbed power in the squat lifting. The knee and ankle joints absorbed power, the hip and lumbar joints generated power in the stoop lifting. The bi-articular antagonist muscles' co-contraction around the knee joint during the squat lifting and the eccentric co-contraction of the gastrocnemius and the biceps femoris were found important for maintaining the straight leg during the stoop lifting. At the time of lordotic curvature appearance in the squat lifting, there were significant correlations in all three lower extremity joint moments with the lumbar joint. Differently, only the hip moment had significant correlation with the lumbar joint in the stoop lifting.</p> <p>Conclusion</p> <p>In conclusion, the knee extension which is prominent kinematics during the squat lifting was produced by the contributions of the kinetic factors from the hip and ankle joints(extensor moment and power generation) and the lumbar extension which is prominent kinematics during the stoop lifting could be produced by the contributions of the knee joint kinetic factors(flexor moment, power absorption, bi-articular muscle function).</p

    Itinerant Ferromagnetism in the Periodic Anderson Model

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    We introduce a novel mechanism for itinerant ferromagnetism, based on a simple two-band model. The model includes an uncorrelated and dispersive band hybridized with a second band which is narrow and correlated. The simplest Hamiltonian containing these ingredients is the Periodic Anderson Model (PAM). Using quantum Monte Carlo and analytical methods, we show that the PAM and an extension of it contain the new mechanism and exhibit a non-saturated ferromagnetic ground state in the intermediate valence regime. We propose that the mechanism, which does not assume an intra atomic Hund's coupling, is present in both the iron group and in some f electron compounds like Ce(Rh_{1-x} Ru_x)_3 B_2, La_x Ce_{1-x} Rh_3 B_2 and the uranium monochalcogenides US, USe, and UTe

    When a Repository Is Not Enough: Redesigning a Digital Ecosystem to Serve Scholarly Communication

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    INTRODUCTION Our library’s digital asset management system (DAMS) was no longer meeting digital asset management requirements or expanding scholarly communication needs. We formed a multiunit task force (TF) to (1) survey and identify existing and emerging institutional needs; (2) research available DAMS (open source and proprietary) and assess their potential fit; and (3) deploy software locally for in-depth testing and evaluation. DESCRIPTION OF PROGRAM We winnowed a field of 25 potential DAMS down to 5 for deployment and evaluation. The process included selection and identification of test collections and the creation of a multipart task based rubric based on library and campus needs assessments. Time constraints and DAMS deployment limitations prompted a move toward a new evaluation iteration: a shorter criteria-based rubric. LESSONS LEARNED We discovered that no single DAMS was “just right,” nor was any single DAMS a static product. Changing and expanding scholarly communication and digital needs could only be met by the more flexible approach offered by a multicomponent digital asset management ecosystem (DAME), described in this study. We encountered obstacles related to testing complex, rapidly evolving software available in a range of configurations and flavors (including tiers of vendor-hosted functionality) and time and capacity constraints curtailed in-depth testing. While we anticipate long-term benefits from “going further together” by including university-wide representation in the task force, there were trade-offs in distributing responsibilities and diffusing priorities. NEXT STEPS Shifts in scholarly communication at multiple levels—institutional, regional, consortial, national, and international—have already necessitated continual review and adjustment of our digital systems
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