1,168 research outputs found

    Comparision of the estimation of the least square and genetic algorithm throuth serval function in R

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    R software is considered software in which various available functions make it possible to conduct extensive statistical calculations. Genetic algorithm is a method through which we search for approximate solution in optimization. This article aims at evaluating the functions existed in the R software which are employed for approximate solution in optimization. As a result, there has been produced least squares by usual methods for linear and non-linear models through genetic algorithm in this research.Keywords: Least Squares, Genetic Algorithm, Linear Model, Nonlinear Model, Squares Averag

    General Health Status and Its Related Factors in the Nurses Working in the Educational Hospitals of Shiraz University of Medical Sciences, Shiraz, Iran, 2011

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    Background: Nursing is an extremely stressful profession. Nurses are confronted with a variety of personal, communicational and organizational stresses, which affect their health. Objectives: The current study aimed to assess general health level and its related factors in employed nurses in educational hospitals affiliated to Shiraz University of medical sciences. Materials and Methods: This cross-sectional study was performed on 126 nurses and practical nurses who work in educational hospitals affiliated to Shiraz University of medical sciences selected by multi stage sampling method. Data collecting tools included demographic characteristics and General Health Questionaire-28 (GHQ-28). Descriptive statistics are presented and Chi-square test, t-test, and analysis of variance were used to analyze the data. Results: Of 126 subjects 75 (59.5%) cases were suspects of mental disorders. Also 12.7% had physical disorders, 15.9% had anxiety and sleep disorders, 8.7% had social dysfunction and 6.3% had depression. Average score of mental health was 28.4 .In this study mental health was significantly associated with job satisfaction and economic satisfaction (P < 0.05). Conclusions: With regard to significant relation between mental health, job satisfaction, and economic satisfaction, a system for educating and stress reduction counseling should be established to help nurses effectively coping with stress. Also, improving the work environment, increasing staff, increasing salary, and decreasing working hours may reduce the nurses' exposure to stressful risk factors

    Genetic diversity in the Persian sturgeon, Acipenser percicus, from the south Caspian Sea based on mitochondrial DNA sequences of the control region

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    The Persian sturgeon, Acipenser persicus (Borodin, 1897), is an economically important species, which mainly inhabits the Caspian Sea. However, little is known about its population genetic structure. In this study, variation in nucleotide sequences of the mitochondrial DNA (mtDNA) control region of wild stock Persian sturgeon was determined to assess the genetic diversity among different natural populations of this species. The fish (n = 46) were collected from four sites (Astara, Sefidrood, Noshahr and BandareTurkaman) in the south Caspian Sea. As a result 6 haplotypes and 44 variable sites were found. The average haplotype diversity (h) and nucleotide diversity (π) were 0.640±0.028 and 0.0442±0.011, respectively. Analysis of molecular variance (AMOVA) demonstrated that most variations occurred within samples, and the difference between the populations from Astara and Noshahr or Bandare- Turkaman was not significant (p <0.001). Estimates of gene flow indicated reproductive isolation between the Sefidrood River population and the other collections. The divergence might be related to geographical isolation. The results are consistent with the findings from PCR-RFLP analysis (PCR-RFLP) and suggest considerable genetic diversity of the population from Sefidrood River

    Genetic relationships among collections of the Persian sturgeon, Acipenser persicus, in the south Caspian Sea detected by mitochondrial DNA–Restriction fragment length polymorphisms

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    In the present study, mitochondrial DNA polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was used to assess the population structure and genetic relationships among six Persian sturgeon, Acipenser persicus populations from the south Caspian Sea along the Iranian coast. The complete nucleotide dehydrogenase subunit 5 (NADH 5) region of mtDNA amplified by PCR was digested with five restriction enzymes. In total, 154 individuals from six populations including: Guilan (Zone1-2), Mazandaran (Zone 3 and 5), Golestan (Zone 4) and Sefidroud River, from the south Caspian Sea along the Iranian coast were analyzed using five restriction endonucleases (Rsa І, Hinf І, HaeIII, Mbo І and Cfr13І), yielding 17 haplotypes. Samples from Sefidroud River were clearly identified by cluster and molecular variance model (AMOVA) analyses. This collection showed dominant haplotypes that were little in populations from the other geographic areas. The mean haplotype diversity (h) and nucleotide diversity (π) were 0.739±0.038 and 0.0105±0.0043, respectively. Based on heterogeneity test haplotype frequencies of Persian sturgeon populations and Monte-Carlo with 1000 replicates in PCR-RFLP method significant differences were seen (χ2 =37.12, P< 0.0001) and these results showed that haplotype distribution in different location were significant and populations of Sefidroud River were statistically significant (P< 0.0001). This result suggests that the unique genetic structure of Sefidroud River represents a highly valuable genetic resource and should now be treated as demographically independent and managed separately

    Turbulence Time Series Data Hole Filling using Karhunen-Loeve and ARIMA methods

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    Measurements of optical turbulence time series data using unattended instruments over long time intervals inevitably lead to data drop-outs or degraded signals. We present a comparison of methods using both Principal Component Analysis, which is also known as the Karhunen--Loeve decomposition, and ARIMA that seek to correct for these event-induced and mechanically-induced signal drop-outs and degradations. We report on the quality of the correction by examining the Intrinsic Mode Functions generated by Empirical Mode Decomposition. The data studied are optical turbulence parameter time series from a commercial long path length optical anemometer/scintillometer, measured over several hundred metres in outdoor environments.Comment: 8 pages, 9 figures, submitted to ICOLAD 2007, City University, London, U

    Previsão da resistência de geopolímeros monofásicos

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    The discovery of one-part geopolymers is considered a key event on the evolution of geopolymer technology because emulates one of the most important properties of Portland cement, the just add water concept. This materials are not associated with the known problems of two part geopolymers, namely the use of caustic solutions that have poor workability and make the handling and application of geopolymers difficult and the fact that alkaline or soluble silicates are not consumed during geopolymerization leading to severe efflorescence phenomena. However, so far very few investigations were published on this field and some report low mechanical strength. This paper discloses results regarding the numerical modelling of one part-geopolymers compressive strength.A descoberta dos geopolímeros monofásicos é considerado um importante acontecimento no âmbito da tecnologia dos geopolímeros porque mimetizam uma das mais importantes propriedades do cimento Portland, o conceito relativo à simples adição de água. Estes materiais não estão associados aos conhecidos problemas dos geopolímeros correntes nomeadamente a utilização de soluções cáusticas, baixa trabalhabilidade que dificultam a sua colocação e o facto das espécies alcalinas e silicatos solúveis não reagirem na sua totalidade durante a reacção de geopolímerização originando o aparecimento de elevada quantidade de eflorescências. Contudo muito poucas investigações foram publicadas neste domínio e algumas apresentam baixa resistência mecânica. Este artigo apresenta resultados relativos à modelação numérica da resistência à compressão de geopolímeros monofásicos.info:eu-repo/semantics/publishedVersio

    ALMA observations of the Extended Green Object G19.01-0.03 : II. A massive protostar with typical chemical abundances surrounded by four low-mass prestellar core candidates

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    Funding: GMW acknowledges support from the UK’s Science and Technology Facilities Council (STFC) under ST/W00125X/1. CJC acknowledges support from the UK’s STFC under ST/M001296/1. PN acknowledges support by grant 618.000.001 from the Dutch Research Council (NWO) and support by the Danish National Research Foundation through the Center of Excellence "InterCat" (Grant agreement no.: DNRF150).We present a study of the physical and chemical properties of the Extended Green Object (EGO) G19.01−0.03 using sub-arcsecond angular resolution Atacama Large Millimeter/submillimeter Array (ALMA) 1.05 mm and Karl G. Jansky Very Large Array (VLA) 1.21 cm data. G19.01−0.03 MM1, the millimetre source associated with the central massive young stellar object (MYSO), appeared isolated and potentially chemically young in previous Submillimeter Array observations. In our ∼0.4″-resolution ALMA data, MM1 has four low-mass millimetre companions within 0.12 pc, all lacking maser or outflow emission, indicating they may be prestellar cores. With a rich ALMA spectrum full of complex organic molecules, MM1 does not appear chemically young, but has molecular abundances typical of high-mass hot cores in the literature. At the 1.05 mm continuum peak of MM1, N(CH3OH) = (2.22 ± 0.01) × 1018 cm−2 and Tex=162.7+0.3−0.5 K based on pixel-by-pixel Bayesian analysis of LTE synthetic methanol spectra across MM1. Intriguingly, the peak CH3OH Tex = 165.5 ± 0.6 K is offset from MM1’s millimetre continuum peak by 0.22″ ∼ 880 AU, and a region of elevated CH3OH Tex coincides with free-free VLA 5.01 cm continuum, adding to the tentative evidence for a possible unresolved high-mass binary in MM1. In our VLA 1.21 cm data, we report the first NH3(3,3) maser detections towards G19.01−0.03, along with candidate 25 GHz CH3OH 5(2, 3) − 5(1, 4) maser emission; both are spatially and kinematically coincident with 44 GHz Class I CH3OH masers in the MM1 outflow. We also report the ALMA detection of candidate 278.3 GHz Class I CH3OH maser emission towards this outflow, strengthening the connection of these three maser types to MYSO outflows.Publisher PDFPeer reviewe
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