855 research outputs found

    IRIS Observations of Spicules and Structures Near the Solar Limb

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    We have analyzed IRIS spectral and slit-jaw observations of a quiet region near the South Pole. In this article we present an overview of the observations, the corrections, and the absolute calibration of the intensity. We focus on the average profiles of strong (Mg ii h and k, C ii and Si iv), as well as of weak spectral lines in the near ultraviolet (NUV) and the far ultraviolet (FUV), including the Mg ii triplet, thus probing the solar atmosphere from the low chromosphere to the transition region. We give the radial variation of bulk spectral parameters as well as line ratios and turbulent velocities. We present measurements of the formation height in lines and in the NUV continuum, from which we find a linear relationship between the position of the limb and the intensity scale height. We also find that low forming lines, such as the Mg ii triplet, show no temporal variations above the limb associated with spicules, suggesting that such lines are formed in a homogeneous atmospheric layer and, possibly, that spicules are formed above the height of 2 arc sec. We discuss the spatio-temporal structure near the limb from images of intensity as a function of position and time. In these images, we identify p-mode oscillations in the cores of lines formed at low heights above the photosphere, slow moving bright features in O i and fast moving bright features in C ii. Finally, we compare the Mg ii k and h line profiles, together with intensity values of the Balmer lines from the literature, with computations from the PROM57Mg non-LTE model developed at the Institut d'Astrophysique Spatiale and estimated values of the physical parameters. We obtain electron temperatures in the range of ∌8000\sim8000 K at small heights to ∌20000\sim20000 K at large heights, electron densities from 1.1×10111.1 \times 10^{11} to 4×10104 \times 10^{10} cm−3^{-3} and a turbulent velocity of ∌24\sim24km/s.Comment: Accepted for publication in Solar Physic

    Management Entrenchment in the Market for Corporate Control

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    Ken C.Yook, Ph.D., is associate professor of finance. Department of Finance, The Johns Hopkins University, Washington, DC 20036. George M. McCabe, Ph.D., is professor of finance, Department of Finance, University of Nebraska-Lincoln, Lincoln, NE 68588

    An Application Of An Artificial Neural Network Investment System To Predict Takeover Targets

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    Artificial neural networks are a robust, effective complement to traditional statistical methods in financial applications. They can incorporate qualitative and quantitative information, and recognize underlying patterns and trends in large, complex data sets.  This paper applies a neural network model to identify potential acquisition targets. The model incorporates various factors based on acquisition theories suggested in the literature.  The resulting neural network model exhibits a highly successful prediction rate and a portfolio of predicted target stocks identified by the network substantially outperformed the market

    Application of the cellular oxidation biosensor to Toxicity Identification Evaluations for high-throughput toxicity assessment of river water

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    Toxicity Identification Evaluation (TIE) is a useful method for the classification and identification of toxicants in a composite environment water sample. However, its extension to a larger sample size has been restrained owing to the limited throughput of toxicity bioassays. Here we reported the development of a high-throughput method of TIE Phase I. This newly developed method was assisted by the fluorescence-based cellular oxidation (CO) biosensor fabricated with roGFP2-expressing bacterial cells in 96-well microplate format. The assessment of four river water samples from Langat river basin by this new method demonstrated that the contaminant composition of the four samples can be classified into two distinct groups. The entire toxicity assay consisted of 2338 tests was completed within 12 h with a fluorescence microplate reader. Concurrently, the sample volume for each assay was reduced to 50 ÎŒL, which is 600 to 4700 times lesser to compare with conventional bioassays. These imply that the throughput of the CO biosensor-assisted TIE Phase I is now feasible for constructing a large-scale toxicity monitoring system, which would cover a whole watershed scale

    A Scaling-up Synthesis From Laboratory Scale to Pilot Scale and to Near Commercial Scale for Paste-Glue Production

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    This paper concerns on developing a synthesis method of paste-glue production for gummed tape using a corn-based starch as an alternative feedstock from laboratory-scale to pilot-scale and to near commercial scale. Basically, two methods of synthesis were developed to produce paste-glue in laboratory scale. Based on the two methods, we then scale-up the earlier laboratory scale data to pilot-scale and near commercial-scale for developing a large scale process production of paste-glue. Scaling up production from 1,000 ml reactor to 500 L pilot-scale reactor and 1,500 L near commercial scale reactor, we monitored pathway of temperature increase during reaction as well as adjustment of operating condition conducted for laboratory experimental data in order to produce a good quality of paste-glue. Some scaling up parameters have been found as well as critical parameters for a good product quality such as viscosity and ceiling temperature of the reaction which are very crucial in order to give optimum operating condition. We have selected synthesis method of paste-glue production and found the range of the parameters in order to produce a very good quality of paste-glue in pilot scale and near commercial scale

    Cellular Characterization of SARS Coronavirus Nucleocapsid

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    The Severe and Acute Respiratory Syndrome coronavirus (SARS CoV) is a newly-emerged virus that caused an outbreak of atypical pneumonia in the winter of 2002-2003. Polyclonal antibodies raised against the nucleocapsid (N) of the SARS CoV showed the localization of N to the cytoplasm and the nucleolus in virus-infected and N-expressing Vero E6 cells. Like other coronavirus N proteins, the SARS N is probably a phosphoprotein. N protein expressed in mammalian cells is apparently able to “spread” to neighboring cells. For N to spread to neighboring cells, it must be exported out of the expressing cells. This is shown by the immunoprecipitation of N from the culture medium of a stable cell line expressing myc-N. Deletion studies showed that the 27 kD C-terminal domain of N (C1/2) is the minimal region of N that can spread to other cells. The nucleolar localization and spreading of N are artefacts of fixation, reminiscent of other protein-transduction domain (PTD)-containing proteinsWeb of Scienc

    WormBase 2007

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    WormBase (www.wormbase.org) is the major publicly available database of information about Caenorhabditis elegans, an important system for basic biological and biomedical research. Derived from the initial ACeDB database of C. elegans genetic and sequence information, WormBase now includes the genomic, anatomical and functional information about C. elegans, other Caenorhabditis species and other nematodes. As such, it is a crucial resource not only for C. elegans biologists but the larger biomedical and bioinformatics communities. Coverage of core areas of C. elegans biology will allow the biomedical community to make full use of the results of intensive molecular genetic analysis and functional genomic studies of this organism. Improved search and display tools, wider cross-species comparisons and extended ontologies are some of the features that will help scientists extend their research and take advantage of other nematode species genome sequences

    An air-stable DPP-thieno-TTF copolymer for single-material solar cell devices and field effect transistors

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    Following an approach developed in our group to incorporate tetrathiafulvalene (TTF) units into conjugated polymeric systems, we have studied a low band gap polymer incorporating TTF as a donor component. This polymer is based on a fused thieno-TTF unit that enables the direct incorporation of the TTF unit into the polymer, and a second comonomer based on the diketopyrrolopyrrole (DPP) molecule. These units represent a donor–acceptor copolymer system, p(DPP-TTF), showing strong absorption in the UV–visible region of the spectrum. An optimized p(DPP-TTF) polymer organic field effect transistor and a single material organic solar cell device showed excellent performance with a hole mobility of up to 5.3 × 10–2 cm2/(V s) and a power conversion efficiency (PCE) of 0.3%, respectively. Bulk heterojunction organic photovoltaic devices of p(DPP-TTF) blended with phenyl-C71-butyric acid methyl ester (PC71BM) exhibited a PCE of 1.8%
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