389 research outputs found

    A Search For Supernova Remnants in The Nearby Spiral Galaxy M74 (NGC 628)

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    We have identified nine new SNR candidates in M74 with [S II]/Hα\alpha ≥\geq 0.4 as the basic criterion. We obtain [S II]/Hα\alpha ratio in the range from 0.40 to 0.91 and Hα\alpha intensities from 2.8 ×\times 10−1510^{-15} erg cm−2^{-2} s−1^{-1} to 1.7 ×\times 10−1410^{-14} erg cm−2^{-2} s−1^{-1}. We also present spectral follow-up observations of the SNR candidates and can confirm only three of them (SNR2, SNR3, and SNR5). The lack of confirmation for the rest might be due to the contamination by the nearby H II emission regions as well as due to the inaccurate positioning of the long slit on these objects. In addition, we search the ChandraChandra Observatory archival data for the X-ray counterparts to the optically identified candidates. We find positional coincidence with only three SNR candidates, SNR1, SNR2, and SNR8. The spectrum of SNR2 yields a shock temperature of 10.8 keV with an ionization timescale of 1.6 ×\times 1010^{10} s cm−3^{-3} indicating a relatively young remnant in an early Sedov phase which is not supported by our optical wavelength analysis. Given the high luminosity of 1039^{39} erg s−1^{-1} and the characteristics of the X-ray spectrum, we favor an Ultra Luminous X-ray Source interpretation for this source associated with an SNR. We calculate an X-ray flux upper limit of 9.0 ×\times 10−1510^{-15} erg cm−2^{-2} s−1^{-1} for the rest of the SNRs including spectroscopically identified SNR3 and SNR5.Comment: 10 pages, 8 figures, accepted to be published in A&

    Closed-Form Green's Function Representations for Mutual Coupling Calculations Between Apertures on a Perfect Electric Conductor Circular Cylinder Covered with Dielectric Layers

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    Cataloged from PDF version of article.Closed-form Green’s function (CFGF) representations are developed for tangential magnetic current sources to calculate the mutual coupling between apertures on perfectly conducting circular cylinders covered with dielectric layers. The new representations are obtained by first rewriting the corresponding spectral domain Green’s function representations in a different form (so that accurate results for electrically large cylinders, and along the axial line of a cylinder can be obtained). Then, the summation over the cylindrical eigenmodes is calculated efficiently. Finally, the resulting expressions are transformed to the spatial domain using a modified two-level generalized pencil of function method. Numerical results are presented showing good agreement when compared to CST Microwave Studio results

    The TIGRE gamma-ray telescope

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    TIGRE is an advanced telescope for gamma-ray astronomy with a few arcmin resolution. From 0.3 to 10 MeV it is a Compton telescope. Above 1 MeV, its multi-layers of double sided silicon strip detectors allow for Compton recoil electron tracking and the unique determination for incident photon direction. From 10 to 100 MeV the tracking feature is utilized for gamma-ray pair event reconstruction. Here we present TIGRE energy resolutions, background simulations and the development of the electronics readout system

    The Columbia, Missouri, Heat Island Experiment (COHIX) and the Influence of a Small City on the Local Climatology

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    The heat island effect is a well known feature in the microclimate of urban areas but only a few studies have addressed the effect for smaller urban areas. We examine here the impact of Columbia, Missouri and the University of Missouri campus on the microclimate (temperature and precipitation) of central Missouri. We purchased twenty Radio Shack® digital Max/Min thermometers and ten standard raised-edge rain gauges and these were given to students, staff, and faculty participants who were chosen for their reliability to provide daily data over the course of a year, site the instrument, and their location (in order to provide reasonable coverage locally). We also included information provided by automated and cooperative weather stations, and the weather station at the regional airport located 11 km (7 miles) southeast of Columbia. Our results indicate that the city has no discernable impact on the distribution of monthly precipitation totals. We found a distinct urban influence on the local surface temperatures, and the inner city region and the urbanized area of south Columbia were approximately 2 - 3 oF (1.0 - 1.5 oC) warmer in the mean than the surrounding environment. This difference grows to 3 - 6 oF (1.5 - 3.5 oC) when comparing the mean of the warmest station in the city to that of coolest station outside Columbia. We also observed a seasonal influence, as the heat island effect was more evident in the mean monthly maximum (minimum) temperatures during the warmest (coldest) months

    From Too Much to Too Little: How the central U.S. drought of 2012 evolved out of one of the most devastating floods on record in 2011

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    Table of Contents Section 1: Introduction....................................................................... 1 Section 2: Regional Drought Perspective................................. 2 Section 3: State Drought Perspectives........................................ 3 Section 3.1: Colorado........................................................................... 20 Section 3.2: Illinois.................................................................. 25 Section 3.3: Indiana................................................. 29 Section 3.4: Iowa...................... 36 Section 3.5: Kansas............................................................... 42 Section 3.6: Kentucky............................................................................ 46 Section 3.7: Michigan.............................. 52 Section 3.8: Minnesota............................................................ 58 Section 3.9: Missouri..................................................... 63 Section 3.10: Nebraska................................................. 67 Section 3.11: North Dakota............................................ 73 Section 3.12: Ohio................................................... 79 Section 3.13: South Dakota..................................... 85 Section 3.14: Wyoming........................................... 96 Section 4: Conclusions.............................................................. 9

    Import Substitution Industrialization [ISI]: An approach to Global Economic Sustainability

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    Globalisation has over the years brought about openness, thus creating an inextricable link among countries through various channels, including trade and investment. Consequently, there has been a substantial expansion in trade in goods and services and the flow of foreign direct investment between developed and developing countries. Even though, both have benefitted from this global openness, the balance of benefits is mainly tilted to developed countries, reinforced by the fact that developing countries have been importing more and exporting less to these countries – a reflection of the under-developed state of their industrial sector, which is evident in their export of mainly unrefined or primary products, with little or no value addition taking place. This gives attestation to the presence of an insignificant import substitution-oriented manufacturing activity in such countries, which have rendered them heavily reliant on imports for their survival – by extension making them highly susceptible to external risks and shocks. This brought about the inception of ISI, which originated from as early as in the 1930s through into the 1960s in Latin America and some parts of Asia and Africa – a notion that was meant to incorporate three stages, namely ‘domestic production of previously imported non-durable consumer goods, extension of production to a wide-range of consumer durables and complex manufactured items and finally, exporting of manufactured goods, with the vision of diversifying to multiple range of items’ (Bussell,, n/d)

    Functional bowel disorders with diarrhoea: Clinical guidelines of the United European Gastroenterology and European Society for Neurogastroenterology and Motility

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    Irritable bowel syndrome with diarrhoea (IBS-D) and functional diarrhoea (FDr) are the two major functional bowel disorders characterized by diarrhoea. In spite of their high prevalence, IBS-D and FDr are associated with major uncertainties, especially regarding their optimal diagnostic work-up and management. A Delphi consensus was performed with experts from 10 European countries who conducted a literature summary and voting process on 31 statements. Quality of evidence was evaluated using the grading of recommendations, assessment, development, and evaluation criteria. Consensus (defined as >80% agreement) was reached for all the statements. The panel agreed with the potential overlapping of IBS-D and FDr. In terms of diagnosis, the consensus supports a symptom-based approach also with the exclusion of alarm symptoms, recommending the evaluation of full blood count, C-reactive protein, serology for coeliac disease, and faecal calprotectin, and consideration of diagnosing bile acid diarrhoea. Colonoscopy with random biopsies in both the right and left colon is recommended in patients older than 50 years and in presence of alarm features. Regarding treatment, a strong consensus was achieved for the use of a diet low fermentable oligo-, di-, monosaccharides and polyols, gut-directed psychological therapies, rifaximin, loperamide, and eluxadoline. A weak or conditional recommendation was achieved for antispasmodics, probiotics, tryciclic antidepressants, bile acid sequestrants, 5-hydroxytryptamine-3 antagonists (i.e. alosetron, ondansetron, or ramosetron). A multinational group of European experts summarized the current state of consensus on the definition, diagnosis, and management of IBS-D and FDr
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