1,806 research outputs found
Chronicles of Oklahoma
Notes and Documents section for Volume 48, Number 4, Winter 1970-71. It includes a narrative of a historical train trip through northern and eastern states, correspondence between the society's president and the letter's author regarding the making of the account, a chronicle of the history of the oldest boarding school operated in the United States called the Riverside Indian School, and an Oklahoma weather report
An Overview of Aeropropulsion Wind Tunnel Productivity Improvements at the NASA Lewis Research Center
Enhancing wind tunnel test productivity in terms of increased efficiency, reduced cost, and expanded flexibility is a high-priofity goal of the NASA Lewis Research Center's Aeropropulsion Facilities and Experiments Division. Over the past several years, several significant productivity improvements were implemented: test times were shortened by using facility and test article automation; additional flexibility was provided to the research customer by using the remote-access control room and by expanding facility operating envelopes; facility throughput was greatly increased and electric power cost for facility operation reduced by using the three-shift operation. One method being used to reduce electric power costs and expand the facility operating envelop in the 8- by 6-Foot Supersonic Wind Tunnel is operating the drive system with only one of the three drive motors. Metrics are being used to document several categories of facility utilization, which in turn allows tracking of test productivity. This paper provides an overview of the productivity improvements already in place in the large wind tunnels at NASA Lewis and presents plans for future improvements
Uncertainty in geomorphological responses to climate change
Acknowledgements We acknowledge the careful comments from two anonymous reviewers. Funding information This work was partly supported by a Middlesex University PhD Studentship to EA and a Coventry University PhD Studentship to PA. NERC for radiocarbon dating provided funding support.Peer reviewedPublisher PD
Sperm is epigenetically programmed to regulate gene transcription in embryos.
For a long time, it has been assumed that the only role of sperm at fertilization is to introduce the male genome into the egg. Recently, ideas have emerged that the epigenetic state of the sperm nucleus could influence transcription in the embryo. However, conflicting reports have challenged the existence of epigenetic marks on sperm genes, and there are no functional tests supporting the role of sperm epigenetic marking on embryonic gene expression. Here, we show that sperm is epigenetically programmed to regulate embryonic gene expression. By comparing the development of sperm- and spermatid-derived frog embryos, we show that the programming of sperm for successful development relates to its ability to regulate transcription of a set of developmentally important genes. During spermatid maturation into sperm, these genes lose H3K4me2/3 and retain H3K27me3 marks. Experimental removal of these epigenetic marks at fertilization de-regulates gene expression in the resulting embryos in a paternal chromatin-dependent manner. This demonstrates that epigenetic instructions delivered by the sperm at fertilization are required for correct regulation of gene expression in the future embryos. The epigenetic mechanisms of developmental programming revealed here are likely to relate to the mechanisms involved in transgenerational transmission of acquired traits. Understanding how parental experience can influence development of the progeny has broad potential for improving human health.We thank: T. Jenuwein and N. Shukeir for anti-H3K27me3 antibody; A. Bannister, J.
Ahringer and E. Miska for comments on the manuscript; Gurdon group members for reading
the manuscript; The International Xenopus laevis Genome Project Consortium (the Harland,
Rokhsar, Taira labs and others) for providing unpublished genome and gene annotation
information. M.T. is supported by WT089613 and by MR/K011022/1. V.G. and P.Z. are
funded by AICR 10-0908. A.S. is supported by MR/K011022/1. K.M. is a Research Fellow
at Wolfson College and is supported by the Herchel Smith Postdoctoral Fellowship. E.M.M.
is supported by National Institutes of Health, National Science Foundation, Cancer
Prevention Research Institute of Texas, and the Welch Foundation (F1515). J.J. and J.B.G.
are supported by WT101050/Z/13/Z. S.E. acknowledges Boehringer Ingelheim Fond
fellowship. A.H.F.M.P. is supported by the Swiss National Science Foundation
(31003A_125386) and the Novartis Research Foundation. All members of the Gurdon
Institute acknowledge the core support provided by CRUK C6946/A14492 and WT092096.This is the final version of the article. It first appeared from Cold Spring Harbor Laboratory Press via https://doi.org/10.1101/gr.201541.11
Isolation of Vaccine-Like Poliovirus Strains in Sewage Samples From the United Kingdom.
Background: Environmental surveillance (ES) is a sensitive method for detecting human enterovirus (HEV) circulation, and it is used worldwide to support global polio eradication. We describe a novel ES approach using next-generation sequencing (NGS) to identify HEVs in sewage samples collected in London, United Kingdom, from June 2016 to May 2017. Methods: Two different methods were used to process raw sewage specimens: a 2-phase aqueous separation system and size exclusion by filtration and centrifugation. HEVs were isolated using cell cultures and analyzed using NGS. Results: Type 1 and 3 vaccine-like poliovirus (PV) strains were detected in samples collected from September 2016 through January 2017. NGS analysis allowed us to rapidly obtain whole-genome sequences of PV and non-PV HEV strains. As many as 6 virus strains from different HEV serotypes were identified in a single cell culture flask. PV isolates contained only a small number of mutations from vaccine strains commonly seen in early isolates from vaccinees. Conclusions: Our ES setup has high sensitivity for polio and non-PV HEV detection, generating nearly whole-genome sequence information. Such ES systems provide critical information to assist the polio eradication endgame and contribute to the improvement of our understanding of HEV circulation patterns in humans
The Impossibility of a Perfectly Competitive Labor Market
Using the institutional theory of transaction cost, I demonstrate that the assumptions of the competitive labor market model are internally contradictory and lead to the conclusion that on purely theoretical grounds a perfectly competitive labor market is a logical impossibility. By extension, the familiar diagram of wage determination by supply and demand is also a logical impossibility and the neoclassical labor demand curve is not a well-defined construct. The reason is that the perfectly competitive market model presumes zero transaction cost and with zero transaction cost all labor is hired as independent contractors, implying multi-person firms, the employment relationship, and labor market disappear. With positive transaction cost, on the other hand, employment contracts are incomplete and the labor supply curve to the firm is upward sloping, again causing the labor demand curve to be ill-defined. As a result, theory suggests that wage rates are always and everywhere an amalgam of an administered and bargained price. Working Paper 06-0
Different paths to the modern state in Europe: the interaction between domestic political economy and interstate competition
Theoretical work on state formation and capacity has focused mostly on early modern Europe and on the experience of western European states during this period. While a number of European states monopolized domestic tax collection and achieved gains in state capacity during the early modern era, for others revenues stagnated or even declined, and these variations motivated alternative hypotheses for determinants of fiscal and state capacity. In this study we test the basic hypotheses in the existing literature making use of the large date set we have compiled for all of the leading states across the continent. We find strong empirical support for two prevailing threads in the literature, arguing respectively that interstate wars and changes in economic structure towards an urbanized economy had positive fiscal impact. Regarding the main point of contention in the theoretical literature, whether it was representative or authoritarian political regimes that facilitated the gains in fiscal capacity, we do not find conclusive evidence that one performed better than the other. Instead, the empirical evidence we have gathered lends supports to the hypothesis that when under pressure of war, the fiscal performance of representative regimes was better in the more urbanized-commercial economies and the fiscal performance of authoritarian regimes was better in rural-agrarian economie
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