1,977 research outputs found

    Modal analysis of Bragg onion resonators

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    From analysis of the high Q modes in a Bragg onion resonator with an omnidirectional reflector cladding, we establish a close analogy between such a resonator and a spherical hollow cavity in perfect metal. We demonstrate that onion resonators are ideal for applications that require a large spontaneous-emission factor ß, such as thresholdless lasers and single-photon devices

    Respiratory Sinus Arrhythmia Activity Predicts Internalizing and Externalizing Behaviors in Non-referred Boys

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    Atypical respiratory sinus arrhythmia (RSA), a biomarker of emotion dysregulation, is associated with both externalizing and internalizing behaviors. In addition, social adversity and gender may moderate this association. In this study, we investigated if RSA (both resting RSA and RSA reactivity in an emotion regulation task) predicts externalizing and/or internalizing behaviors and the extent to which social adversity moderates this relationship. Two hundred and fifty-three children (at Time 1, mean age D 9.05, SD D 0.60, 48% boys) and their caregivers from the community participated in this study. Resting RSA and RSA reactivity were assessed, and caregivers reported children’s externalizing and internalizing behaviors at both Time 1 and Time 2 (1 year later). We found that lower resting RSA (but not RSA reactivity) at Time 1 was associated with increased externalizing and internalizing behaviors at Time 2 in boys, even after controlling for the effects of Time 1 behavioral problems and Time 2 age. Moreover, there was a significant interaction effect between Time 1 resting RSA and social adversity such that lower resting RSA predicted higher externalizing and internalizing behaviors in boys only under conditions of high social adversity. Follow-up analyses revealed that these predictive effects were stronger for externalizing behavior than for internalizing behavior. No significant effects were found for girls. Our findings provide further evidence that low resting RSA may be a transdiagnostic biomarker of emotion dysregulation and a predisposing risk factor for both types of behavior problems, in particular for boys who grow up in adverse environments. We conclude that biosocial interaction effects and gender differences should be considered when examining the etiological mechanisms of child psychopathology

    Microarray analysis of genes affected by salt stress in tomato

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    Large-scale gene expression affected by salt stress was analyzed with tomato seedlings (Lycoperson esculentum Mill cv. Money Maker) by a cDNA microarray (Tom1). The significantly differentially expressed genes (5% Benjamini-Hochberg false discovery rate) consisted of 1757 sequences in the analyzed tissues (cotyledons + shoot tip). Genes with over 2 fold difference were selected from the list and further categorized into different function and cellular processes. Tomato homologous genes for the chaperone proteins, antioxidant enzymes (catalase and peroxidase), and ion transporters (Na+- driven multidrug efflux pump, vacuolar ATPase, and others) were induced. The ACC oxidase and ethylene-responsive gene tomato homologs had higher transcript level after salt treatment. Multiple members with different expression patterns were identified for the bZIP, WRKY, and MADS-box transcription regulator. Different genes in the signal transduction pathway, such as the protein kinases (Shaggy kinase, mitogen-activated protein kinase, ethylene receptor neverripe, and others), protein phosphatases, calmodulin, G-protein, and the N- myristoyltransferase were regulated by salt stress. Most of the protease and the inhibitor homologs were suppressed by salt stress. In addition, different isoforms of cytochrome P450, genes for polyamine biosynthesis (putrescine and proline) and detoxification compounds (glutathione and thioredoxin), several key enzyme genes in the metabolic pathways of carbohydrates, amino acids, and fatty acids, were also affected by salt treatment. This study has provided a set of candidate genes, especially those in the regulatory machinery that can be further investigated to define salt stress in tomato and other plant species.Keywords: Antioxidants, cellular metabolism, cell wall, chaperonine, ethylene, protein kinase, tomato, transcription regulator, translation regulator, salt stres

    Complex and diverse rupture processes of the 2018 Mw 8.2 and Mw 7.9 Tonga-Fiji deep earthquakes

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    Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 46(5), (2019):2434-2448, doi:10.1029/2018GL080997.Deep earthquakes exhibit strong variabilities in their rupture and aftershock characteristics, yet their physical failure mechanisms remain elusive. The 2018 Mw 8.2 and Mw 7.9 Tonga‐Fiji deep earthquakes, the two largest ever recorded in this subduction zone, occurred within days of each other. We investigate these events by performing waveform analysis, teleseismic P wave backprojection, and aftershock relocation. Our results show that the Mw 8.2 earthquake ruptured fast (4.1 km/s) and excited frequency‐dependent seismic radiation, whereas the Mw 7.9 earthquake ruptured slowly (2.5 km/s). Both events lasted ∼35 s. The Mw 8.2 earthquake initiated in the highly seismogenic, cold core of the slab and likely ruptured into the surrounding warmer materials, whereas the Mw 7.9 earthquake likely ruptured through a dissipative process in a previously aseismic region. The contrasts in earthquake kinematics and aftershock productivity argue for a combination of at least two primary mechanisms enabling rupture in the region.We thank the Editor Gavin Hayes and two anonymous reviewers for their helpful comments that improved the quality of the manuscript. The seismic data were provided by Data Management Center (DMC) of the Incorporated Research Institutions for Seismology (IRIS). The facilities of IRIS Data Services, and specifically the IRIS Data Management Center, were used for access to waveforms, related metadata, and/or derived products used in this study. IRIS Data Services are funded through the Seismological Facilities for the Advancement of Geoscience and EarthScope (SAGE) Proposal of the National Science Foundation under Cooperative Agreement EAR‐1261681. W. F. acknowledges supports from the Postdoctoral Scholar Program at the Woods Hole Oceanographic Institution, with funding provided by the Weston Howland Postdoctoral Scholarship. S. S. W. and D. T. are supported by the MSU Geological Sciences Endowment.2019-08-2

    A Branch Point of \u3cem\u3eStreptomyces\u3c/em\u3e Sulfur Amino Acid Metabolism Controls the Production of Albomycin

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    Albomycin (ABM), also known as grisein, is a sulfur-containing metabolite produced by Streptomyces griseus ATCC 700974. Genes predicted to be involved in the biosynthesis of ABM and ABM-like molecules are found in the genomes of other actinomycetes. ABM has potent antibacterial activity, and as a result, many attempts have been made to develop ABM into a drug since the last century. Although the productivity of S. griseus can be increased with random mutagenesis methods, understanding of Streptomyces sulfur amino acid (SAA) metabolism, which supplies a precursor for ABM biosynthesis, could lead to improved and stable production. We previously characterized the gene cluster (abm) in the genome-sequenced S. griseus strain and proposed that the sulfur atom of ABM is derived from either cysteine (Cys) or homocysteine (Hcy). The gene product, AbmD, appears to be an important link between primary and secondary sulfur metabolic pathways. Here, we show that propargylglycine or iron supplementation in growth media increased ABM production by significantly changing the relative concentrations of intracellular Cys and Hcy. An SAA metabolic network of S. griseus was constructed. Pathways toward increasing Hcy were shown to positively impact ABM production. The abmD gene and five genes that increased the Hcy/Cys ratio were assembled downstream of hrdBp promoter sequences and integrated into the chromosome for overexpression. The ABM titer of one engineered strain, SCAK3, in a chemically defined medium was consistently improved to levels ∼400% of the wild type. Finally, we analyzed the production and growth of SCAK3 in shake flasks for further process development
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