26 research outputs found

    Stability Analysis of a Discrete Time Model on Plant-Soil Interactions

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    In this paper, a nonlinear mathematical model on plant soil interactions is proposed and analyzed. We consider the variables namely, density of the plant species, nutrient concentration in the soil and in the plant for metabolic activity. We consider that the growth rate of the plant species is dependent on the density of the nutrient concentration in the plant. The relationship between the concentration and the rate of uptake is often described quantitatively by Michaelis?Menten kinetics. We discretize the model by applying Backward Euler method and analyse the stability of the model both locally and globally. We analyse the nutrient concentration in Tomato plant and provide numerical simulations for the dynamical behaviour of plant soil interactions for each nutrient. The numerical simulations are provided using MATLAB

    Improved Low Voltage Ride through Capability of a Fixed Speed Wind Generator Using Dynamic Voltage Restorer

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    AbstractWind energy is one of the fastest growing renewable energy technologies in world. The new grid code proposes that the wind turbine should remain connected to the grid during voltage disturbances. Three phase voltage sags and faults cause reduction in voltage at the point of interconnection to the grid when fixed speed wind turbines connected to squirrel cage induction generators are employed resulting in disconnection of wind turbine from the grid. Dynamic voltage restorer is a series connected custom power device used for voltage compensation during sags and swells. In this paper, the Low voltage ride through capability of a fixed speed wind turbine is improved using dynamic voltage restorer. Simulation studies are done to determine the transient stability of a fixed speed wind turbine with squirrel cage induction generator using Matlab Simulink

    Twin pregnancy with a complete hydatidiform mole and coexisting foetus

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    Coexistence of a viable foetus with a complete hydatidiform mole is a rare entity. Traditionally, termination of pregnancy was recommended because of severe maternal and foetal complications. Here we report a case of a 30 year old G2A1 at 27 weeks with a twin pregnancy with a complete hydatidiform mole and coexisting normal foetus who took home a healthy baby without any persistent trophoblastic disease. This case is presented for the rarity of occurrence and good outcome

    The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

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    The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourteenth from SDSS overall (making this, Data Release Fourteen or DR14). This release makes public data taken by SDSS-IV in its first two years of operation (July 2014-2016). Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey (eBOSS); the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data driven machine learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS website (www.sdss.org) has been updated for this release, and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020, and will be followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14 happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov 2017 (this is the "post-print" and "post-proofs" version; minor corrections only from v1, and most of errors found in proofs corrected

    Genetic diversity fuels gene discovery for tobacco and alcohol use

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    Tobacco and alcohol use are heritable behaviours associated with 15% and 5.3% of worldwide deaths, respectively, due largely to broad increased risk for disease and injury(1-4). These substances are used across the globe, yet genome-wide association studies have focused largely on individuals of European ancestries(5). Here we leveraged global genetic diversity across 3.4 million individuals from four major clines of global ancestry (approximately 21% non-European) to power the discovery and fine-mapping of genomic loci associated with tobacco and alcohol use, to inform function of these loci via ancestry-aware transcriptome-wide association studies, and to evaluate the genetic architecture and predictive power of polygenic risk within and across populations. We found that increases in sample size and genetic diversity improved locus identification and fine-mapping resolution, and that a large majority of the 3,823 associated variants (from 2,143 loci) showed consistent effect sizes across ancestry dimensions. However, polygenic risk scores developed in one ancestry performed poorly in others, highlighting the continued need to increase sample sizes of diverse ancestries to realize any potential benefit of polygenic prediction.Peer reviewe

    The 13th Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey Mapping Nearby Galaxies at Apache Point Observatory

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    The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began observations in July 2014. It pursues three core programs: APOGEE-2,MaNGA, and eBOSS. In addition, eBOSS contains two major subprograms: TDSS and SPIDERS. This paper describes the first data release from SDSS-IV, Data Release 13 (DR13), which contains new data, reanalysis of existing data sets and, like all SDSS data releases, is inclusive of previously released data. DR13 makes publicly available 1390 spatially resolved integral field unit observations of nearby galaxies from MaNGA,the first data released from this survey. It includes new observations from eBOSS, completing SEQUELS. In addition to targeting galaxies and quasars, SEQUELS also targeted variability-selected objects from TDSS and X-ray selected objects from SPIDERS. DR13 includes new reductions ofthe SDSS-III BOSS data, improving the spectrophotometric calibration and redshift classification. DR13 releases new reductions of the APOGEE-1data from SDSS-III, with abundances of elements not previously included and improved stellar parameters for dwarf stars and cooler stars. For the SDSS imaging data, DR13 provides new, more robust and precise photometric calibrations. Several value-added catalogs are being released in tandem with DR13, in particular target catalogs relevant for eBOSS, TDSS, and SPIDERS, and an updated red-clump catalog for APOGEE.This paper describes the location and format of the data now publicly available, as well as providing references to the important technical papers that describe the targeting, observing, and data reduction. The SDSS website, http://www.sdss.org, provides links to the data, tutorials and examples of data access, and extensive documentation of the reduction and analysis procedures. DR13 is the first of a scheduled set that will contain new data and analyses from the planned ~6-year operations of SDSS-IV.PostprintPeer reviewe

    The fifteenth data release of the Sloan Digital Sky Surveys : first release of MaNGA derived quantities, data visualization tools and stellar library

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    Twenty years have passed since first light for the Sloan Digital SkySurvey (SDSS). Here, we release data taken by the fourth phase of SDSS(SDSS-IV) across its first three years of operation (July 2014-July2017). This is the third data release for SDSS-IV, and the fifteenth from SDSS (Data Release Fifteen; DR15). New data come from MaNGA - we release 4824 datacubes, as well as the first stellar spectra in the MaNGA Stellar Library (MaStar), the first set of survey-supported analysis products (e.g. stellar and gas kinematics, emission line, andother maps) from the MaNGA Data Analysis Pipeline (DAP), and a new data visualisation and access tool we call "Marvin". The next data release, DR16, will include new data from both APOGEE-2 and eBOSS; those surveys release no new data here, but we document updates and corrections to their data processing pipelines. The release is cumulative; it also includes the most recent reductions and calibrations of all data taken by SDSS since first light. In this paper we describe the location and format of the data and tools and cite technical references describing how it was obtained and processed. The SDSS website (www.sdss.org) has also been updated, providing links to data downloads, tutorials and examples of data use. While SDSS-IV will continue to collect astronomical data until 2020, and will be followed by SDSS-V(2020-2025), we end this paper by describing plans to ensure the sustainability of the SDSS data archive for many years beyond the collection of data.Publisher PDFPeer reviewe

    DEVELOPMENT OF AN OBJECTIVE QUALITY MEASUREMENT MODEL FOR MEASURING AND EVALUATING QUALITY OF A MANUFACTURING ORGANIZATION

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    ABSTRACT Key to success of an organization depends up on the quality of the products and services provided by the organization. Even though there are many methods for measurement of quality of products and services a proper measurement model for quality of organization is yet to be developed. This paper tries to define quality of an organization and attempts to develop an objective quality measurement model for measuring and evaluating the quality of a manufacturing organization. Employs a case study approach, featuring an electrical equipment manufacturing organization which provides a range of brushless alternators and generators to various customers. The case study organization represents only one industry sector. However it is claimed that the methodology can be adopted for any organization with necessary modifications suited to the organization. The model presented is important in that it can be used to measure and evaluate quality of not only organizations but also processes, systems, products and services with suitable modifications

    Vitamin D deficiency in postmenopausal women with pelvic floor disorders

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    Introduction: The aim of this study is to evaluate the association of vitamin D deficiency and pelvic floor disorders (PFD) including pelvic organ prolapse (POP) and stress urinary incontinence in postmenopausal women. Materials and Methods: This is a prospective case control study on 120 women with or without symptoms of PFD. Relevant history and clinical examination were conducted. Serum 25-hydroxy vitamin D levels were measured in all women. Chi square and student t test were used to test significance of association. Logistic regression was used to adjust for age. Odds ratios and 95% confidence intervals were calculated. Results: Of the 120 postmenopausal women included, 51 had PFD on clinical examination. Of the 51 cases, 28 women had POP and 14 women had stress incontinence (SUI) while nine women had both POP and SUI. The study showed that vitamin D levels were significantly lower in women with PFD than those without PFD. Menopausal status of more than 5 years was also significantly associated with PFD. Conclusion: Findings suggest association of vitamin D deficiency and PFD in postmenopausal women. In addition, postmenopausal women have a high prevalence of vitamin D deficiency indicating a need to evaluate vitamin D levels in these women
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