3,636 research outputs found

    The pattern determination of sea surface temperature distribution and chlorophyll a in the southern Caspian Sea using SOM model

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    Remote sensing has changed modern oceanography by proving synoptic periodic data which can be processed. Since the satellite data are usually too much and nonlinear, in most cases, it is difficult to distinguish the patterns from these images. In fact, SOM (Self-Organizing Maps) model is a type of ANN (Artificial Neural Network) that has the ability to distinguish the efficient patterns from the vast complex of satellite data. In this study, the sea surface temperature data and chlorophyll a related to a part of south Caspian Sea were investigated weekly by NOAA satellite for three years (2003–2005) and the annual and seasonal patterns were extracted (elicited) with their relative frequency using the SOM model. In all patterns the Caspian Sea coast has the highest chl-a and when you go away from the shore the rate decreases and when you approach to the middle parts the chl-a is of the least proportion on the sea surface

    Study of wind waves using satellite altimetry in the coast of south-western Caspian Sea (Gilan Province)

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    576-581Waves are an important phenomena in the sea but in view of complicated nature are difficult to study. This research, with the aim of showing a primary research on satellite altimetry, studied significant wave height in offshore waters near Gilan province in the south-east of Caspian region during 2014. So wave’s data including significant wave height and wind speed were obtained in a time interval from satellite. The significant wave height data were verified with buoy significant wave height data and their graphs generated. Using wave data and SPM method, the significant wave height and wave period obtained. The contour figure of significant wave height was depicted. The comparison of satellite significant wave height data and result of SPM method by buoy data showed that the satellite data has less error than SPM method result. The result of this research has shown that the effective parameters on wind waves are formation of high and low pressure atmospheric system. The maximum value of mean altimetry significant wave height is 0.70 m in November and 0.80 m in December. The maximum of significant wave height occurs in north portion of study region. The dominate direction of waves is north-western in coasts of Gilan province

    Genomic comparison of diverse Salmonella serovars isolated from swine.

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    Food animals act as a reservoir for many foodborne pathogens. Salmonella enterica is one of the leading pathogens that cause food borne illness in a broad host range including animals and humans. They can also be associated with a single host species or a subset of hosts, due to genetic factors associated with colonization and infection. Adult swine are often asymptomatic carriers of a broad range of Salmonella servoars and can act as an important reservoir of infections for humans. In order to understand the genetic variations among different Salmonella serovars, Whole Genome Sequences (WGS) of fourteen Salmonella serovars from swine products were analyzed. More than 75% of the genes were part of the core genome in each isolate and the higher fraction of gene assign to different functional categories in dispensable genes indicated that these genes acquired for better adaptability and diversity. High concordance (97%) was detected between phenotypically confirmed antibiotic resistances and identified antibiotic resistance genes from WGS. The resistance determinants were mainly located on mobile genetic elements (MGE) on plasmids or integrated into the chromosome. Most of known and putative virulence genes were part of the core genome, but a small fraction were detected on MGE. Predicted integrated phage were highly diverse and many harbored virulence, metal resistance, or antibiotic resistance genes. CRISPR (Clustered regularly interspaced short palindromic repeats) patterns revealed the common ancestry or infection history among Salmonella serovars. Overall genomic analysis revealed a great deal of diversity among Salmonella serovars due to acquired genes that enable them to thrive and survive during infection

    Combination T/P and jason-1 satellite altimetry data for determination of sea surface topography in Persian Gulf and Oman Sea

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    Changes and Countries development and need to Scientific, Cultural and Industrial commutation at Global level requires accessibility to maps and spatial information from the entire world. Achieving to this aim requires equalization of horizontal and vertical datum of all countries. Nowadays with developments in technology and after that increasing in precision of vertical datums is one of the basic arguments and there have been efforts to find vertical datum and relations between them. One of the problems that exist in using absolute heights is difference between M.S.L and Geoid. The theoretical basis the absolute heights is Geoid but in practice M.S.L is used as absolute vertical datums. Therefore difference between M.S.L and Geoid is called sea surface topography. In this research one of the all, we have carried out modeling mean sea level using T/P and Jason-1 satellites altimetry data on Persian Gulf and Oman sea , Accordingly Due to the significance of sea level topography in oceanographic studies a new model proposed using the combined satellites altimetry data and the EGM08 global Geoid model in order to determine and equalize the current height datum for Persian Gulf and Oman sea. Therefore, difference between M.S.L derived from T/P and Jason-1 Satellites altimetry data and EGM08 global Geoid model was assessed -0.9 and 1.1 meter respectively

    Carbon nitride as a ligand: edge-site coordination of ReCl(CO)(3)-fragments to g-C3N4

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    IR spectroscopy and model structural studies show binding of ReCl(CO)3-fragments to carbon nitride (g-C3N4) occurs via κ2 N,N′ bidentate coordination

    Single top production in the tt-channel at LHC: a realistic test of electroweak models

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    We compute the complete electroweak one-loop effect on the process of tt-channel single top production at LHC in the Standard Model and in the MSSM within the mSUGRA symmetry breaking scheme. We find that the one-loop electroweak SM effect is large, and decreases the cross section of an amount that is of the same size as that of the NLO QCD one. The genuine SUSY effect in the mSUGRA scheme, for a general choice of benchmark points, is rather small. It might become large and visible in more general scenarios around thresholds involving light stop and neutralino mass values.Comment: 28 pages, 10 eps figure

    Prevalence of high-level gentamicin-resistant Enterococcus faecalis and Enterococcus faecium in an Iranian hospital

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    This study was designed to determine the molecular characteristics and antimicrobial resistance of enterococcal strains isolated from patients admitted to an Iranian Hospital. Enterococcal strains were isolated from the burn patients. All strains were screened for genes encoding resistance to aminoglycoside aac(6')-Ie-aph(2'')-Ia, aph (3'), ant (4'), resistance to vancomycin (vanA, vanB), resistance to tetracycline (tetK, tetL, tetM, tetO), and resistance to erythromycin (ermA, ermB, ermC) by PCR and multiplex PCR-based methods. Genetic diversity was evaluated via Random Amplified Polymorphic DNA (RAPD)-PCR. All enterococcal isolates showed complete sensitivity to vancomycin with MIC � 0.5μg/ml. Resistance to gentamicin, tetracycline, erythromycin, ciprofloxacin or quinopristin-dalfopristin was detected, whilst more than 96.2% of isolates were high-level gentamicinresistant (HLGR) and multiple drug resistant. The most prevalent aminoglycoside resistance gene was aac(6')-Ie-aph(2'')-Ia, that was found in 96.2% (26/27) of the isolates. The most prevalent tetracycline resistance genes were tetM, found in 85.1% (23/27) followed by tetL and tetO found in 7.4% (2/27) of the isolates. The ermA and ermB genes were detected in 33.3% (9/27) and 44.4% (12/27) of the isolates respectively. RAPD-PCR analysis yielded 17 distinct profiles among 27 investigated isolates. One cluster of isolates shared the same RAPD pattern, while 16 isolates had unique RAPD pattern. Our study showed that during the examination time period one RAPD genotype was the common type and was disseminated among patients in the burn unit. Interestingly, most of these strains had an identical or very similar antibiotic and gene resistance pattern

    In situ TEM oxidation study of Fe thin-film transformation to single-crystal magnetite nanoparticles

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    In this work, we present an in situ transmission electron microscopy (TEM) study of Fe thin films to Fe nanoparticle formation and their oxidation to single-crystal magnetite nanoparticles. Amorphous Fe thin films were prepared by sputtering on TEM carbon grids. The thin Fe films were continuously heated in situ from room temperature to 700 °C under vacuum (4 × 10–4 Pa). With the increase in temperature, the continuity of the thin film starts breaking, and Fe nanoparticle nucleation centers are formed. At 600 °C, the thin film transforms into metallic Fe nanoparticles (NPs) with a small presence of different Fe oxide NPs. Further increase in the temperature to 700 °C resulted in the full oxidation of the NPs (i.e., no core–shell were found). Zero-loss energy filtered diffraction and HRTEM analysis of the lattice spacing reveals that all NPs have fully transformed into single-phase magnetite NPs. The structural study of the magnetite NPs shows that magnetite NPs are free of antiphase domain boundary defects. This work demonstrates that under low partial pressure of oxygen at elevated temperatures a complete oxidation of Fe NPs into magnetite single-crystal nanoparticles can be achieved

    Spatial inequalities in the incidence of colorectal cancer and associated factors in the neighborhoods of Tehran, Iran: Bayesian spatial models

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    Objectives: The aim of this study was to determine the factors associated with the spatial distribution of the incidence of colorectal cancer (CRC) in the neighborhoods of Tehran, Iran using Bayesian spatial models. Methods: This ecological study was implemented in Tehran on the neighborhood level. Socioeconomic variables, risk factors, and health costs were extracted from the Equity Assessment Study conducted in Tehran. The data on CRC incidence were extracted from the Iranian population-based cancer registry. The Besag-York-Mollié (BYM) model was used to identify factors associated with the spatial distribution of CRC incidence. The software programs OpenBUGS version 3.2.3, ArcGIS 10.3, and GeoDa were used for the analysis. Results: The Moran index was statistically significant for all the variables studied (p<0.05). The BYM model showed that having a women head of household (median standardized incidence ratio SIR, 1.63; 95% confidence interval CI, 1.06 to 2.53), living in a rental house (median SIR, 0.82; 95% CI, 0.71 to 0.96), not consuming milk daily (median SIR, 0.71; 95% CI, 0.55 to 0.94) and having greater household health expenditures (median SIR, 1.34; 95% CI, 1.06 to 1.68) were associated with a statistically significant elevation in the SIR of CRC. The median (interquartile range) and mean (standard deviation) values of the SIR of CRC, with the inclusion of all the variables studied in the model, were 0.57 (1.01) and 1.05 (1.31), respectively. Conclusions: Inequality was found in the spatial distribution of CRC incidence in Tehran on the neighborhood level. Paying attention to this inequality and the factors associated with it may be useful for resource allocation and developing preventive strategies in at-risk areas. Copyright © 2018 The Korean Society for Preventive Medicine
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