759 research outputs found
The New American Gazette: An Evening with Robert Frost at Ford Hall Forum, transcript
Robert Frost, a Pulitzer Prize winning American poet, addresses his views of America through readings of his poetry. The forum was originally recorded in 1961 and rebroadcast as part of the New American Gazette radio program on March 22, 1990. The radio broadcast is introduced by host Marvin Kalb.https://dc.suffolk.edu/fhf-av/1001/thumbnail.jp
Scan time reduction for readout-segmented EPI using simultaneous multislice acceleration: Diffusion-weighted imaging at 3 and 7 Tesla
Purpose:
Readoutâsegmented echoâplanar imaging (rsâEPI) can provide high quality diffusion data because it is less prone to distortion and blurring artifacts than singleâshot echoâplanar imaging (ssâEPI), particularly at higher resolution and higher field. Readout segmentation allows shorter echoâspacing and echo train duration, resulting in reduced image distortion and blurring, respectively, in the phaseâencoding direction. However, these benefits come at the expense of longer scan times because the segments are acquired in multiple repetitions times (TRs). This study shortened rsâEPI scan times by reducing the TR duration with simultaneous multislice acceleration.
Methods:
The blippedâCAIPI method for slice acceleration with reduced gâfactor SNR loss was incorporated into the diffusionâweighted rsâEPI sequence. The rsâ and ssâEPI sequences were compared at a range of resolutions at both 3 and 7 Tesla in terms of image fidelity and diffusion postprocessing results.
Results:
Sliceâaccelerated clinically useful traceâweighted images and tractography results are presented. Tractography analysis showed that the reduced artifacts in rsâEPI allowed better discrimination of tracts than ssâEPI.
Conclusion:
Slice acceleration reduces rsâEPI scan times providing a practical alternative to diffusionâweighted ssâEPI with reduced distortion and high resolution. Magn Reson Med 74:136â149, 2015
Special Project -- Legal Issues Arising from the Mexican Economic Crisis
The economic crisis in Mexico, which profoundly altered the financial and political course of that nation, has also had a significant impact on persons and corporations having business ties to Mexico. Foreign investors and businesses now are required to follow new Mexican rules that often differ dramatically from those previously in effect. The impact of the crisis has not been confined to changes in Mexican law. A substantial number of issues have arisen that will have significant bearing on United States and international law.
The Special Project discusses the changes in the legal environment following the crisis, with its focus upon issues confronting private persons, principally foreign businesses and investors. The Introduction and Overview summarizes the history and structure of Mexico\u27s regulation of foreign investment and recounts the events of the crisis. The first section of the Special Project examines the problems faced by foreign lenders and creditors. Specifically, it addresses the following: (1) the Mexican regulations that set forth the schedules for repayment of amounts owed to foreign creditors; (2) the possibilities for relief should the obligations be dishonored; (3) the efficacy of leading proposals for the restructuring of Mexican and international debt; and (4) the recently promulgated laws and regulations that will govern future international lending activity by United States banks. The second section explores the problems of investors in devalued peso-denominated accounts and the applicability of United States securities laws to those obligations. Section three addresses the immigration problem now exacerbated by the economic crisis and discusses the scope, effect, and wisdom of the proposed Simpson-Mazzoli Bill. The fourth section studies transborder environmental issues that recently have arisen as a result of Mexico\u27s desire for rapid industrial development
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The catalytic core of DEMETER guides active DNA demethylation in Arabidopsis.
The Arabidopsis DEMETER (DME) DNA glycosylase demethylates the maternal genome in the central cell prior to fertilization and is essential for seed viability. DME preferentially targets small transposons that flank coding genes, influencing their expression and initiating plant gene imprinting. DME also targets intergenic and heterochromatic regions, but how it is recruited to these differing chromatin landscapes is unknown. The C-terminal half of DME consists of 3 conserved regions required for catalysis in vitro. We show that this catalytic core guides active demethylation at endogenous targets, rescuing dme developmental and genomic hypermethylation phenotypes. However, without the N terminus, heterochromatin demethylation is significantly impeded, and abundant CG-methylated genic sequences are ectopically demethylated. Comparative analysis revealed that the conserved DME N-terminal domains are present only in flowering plants, whereas the domain architecture of DME-like proteins in nonvascular plants mainly resembles the catalytic core, suggesting that it might represent the ancestral form of the 5mC DNA glycosylase found in plant lineages. We propose a bipartite model for DME protein action and suggest that the DME N terminus was acquired late during land plant evolution to improve specificity and facilitate demethylation at heterochromatin targets
Chemical composition and geochemistry of the New Albany shale group (Devonian-Mississippian) in Illinois
"Supplement to Final Report, Geologic and Geochemical Studies of the New Albany Shale Group (Devonian-Mississippian) in Illinois, R. E. Bergstrom, N. F. Shimp and Robert M. Cluff, June, 1980."Sponsored by the U. S. Dept. of Energy. DE-AC21-76ET12142.Bibliography: p. 79-83
Magnetic phase transitions in Gd64Sc36 studied using non-contact ultrasonics
The speed and attenuation of ultrasound propagation can be used to determine material properties and identify phase transitions. Standard ultrasonic contact techniques are not always convenient due to the necessity of using couplant; however, recently reliable non-contact ultrasonic techniques involving electromagnetic generation and detection of ultrasound with electromagnetic acoustic transducers (EMATs) have been developed for use on electrically conducting and/or magnetic materials. We present a detailed study of magnetic phase transitions in a single crystal sample of Gd64Sc36 magnetic alloy using contact and non-contact ultrasonic techniques for two orientations of external magnetic field. Phase diagrams are constructed based on measurements of elastic constant C33, the attenuation and the efficiency of generation when using an EMAT. The EMATs are shown to provide additional information related to the magnetic phase transitions in the studied sample, and results identify a conical helix phase in Gd64Sc36 in the magnetic field orientation
Selenium, Folate, and Colon Cancer
Selenium is an essential trace element which has been implicated in cancer risk; however, study results have been inconsistent with regard to colon cancer. Our objectives were to 1) investigate the association between selenium and colon cancer 2) evaluate possible effect measure modifiers and 3) evaluate potential biases associated with the use of post-diagnostic serum selenium measure
Accuracy of High-Speed Video Analysis to Diagnose Primary Ciliary Dyskinesia
Background: primary ciliary dyskinesia (PCD) is a rare genetic disease that impairs motility of cilia. Diagnosis relies on a combination of tests and final decision by multidisciplinary team (MDT). High-speed video microscopy (HSVM) is an important contribution to diagnostic testing, and is the only test that examines cilia motility on the day of patientsâ appointment. No study has assessed the accuracy of HSVM. We hypothesised that scientists experienced in cilia assessment by HSVM would accurately diagnose PCD using HSVM alone compared to MDT diagnosis.Methods: we used 720 archived videos from 120 patients referred to three UK PCD diagnostic services in 2015-17. One scientist from each PCD centre reviewed videos, blinded to diagnostic and clinical data, and scored them for final diagnosis using a standardised proforma. We compared the final scoring for each scientist to: a) a report containing final diagnosis from the MDT decision, and b) diagnostic criteria provided in the 2017 ERS PCD diagnostic guidelines.Results: sensitivity and specificity were: a) 96.1% and 100% respectively when compared to MDT decision, and b) 95.7% and 100% respectively when compared to ERS guidelines criteria. Inter-rater reliability between the three scientists was substantial (k=0.7) for âPCD positiveâ, and moderate (k=0.44) for âPCD highly unlikelyâ.Conclusions: specialist scientists accurately diagnosed PCD using HSVM analysis, with high inter-observer agreement. HSVM can be used to reliably counsel patients on their likely diagnosis on the same day as clinic appointment and inform clinicians on initiation of treatment while confirmatory investigations are conducted
Real-Time Observation of Organic Cation Reorientation in Methylammonium Lead Iodide Perovskites.
The introduction of a mobile and polarized organic moiety as a cation in 3D lead-iodide perovskites brings fascinating optoelectronic properties to these materials. The extent and the time scales of the orientational mobility of the organic cation and the molecular mechanism behind its motion remain unclear, with different experimental and computational approaches providing very different qualitative and quantitative description of the molecular dynamics. Here we use ultrafast 2D vibrational spectroscopy of methylammonium (MA) lead iodide to directly resolve the rotation of the organic cations within the MAPbI3 lattice. Our results reveal two characteristic time constants of motion. Using ab initio molecular dynamics simulations, we identify these as a fast (âŒ300 fs) "wobbling-in-a-cone" motion around the crystal axis and a relatively slow (âŒ3 ps) jump-like reorientation of the molecular dipole with respect to the iodide lattice. The observed dynamics are essential for understanding the electronic properties of perovskite materials.This work was supported by The Netherlands Organization for Scientific Research (NWO) through the âStichting voor Fundamenteel Onderzoek der Materieâ (FOM) research program. A.A.B. also acknowledges a VENI grant from the NWO. A.A.B. is currently a Royal Society University Research Fellow. Z.S. and Z.C. acknowledge the ANR-2011-JS09-004-01-PvCoNano project and the EU Marie Curie Career Integration Grant (303824). A.A.B., Z.S., and Z.C. thank Dutch-French Academy for the support through van Gogh grant.This document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Physical Chemistry Letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/acs.jpclett.5b0155
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