84 research outputs found

    Numerical Study of Soliton Solutions of KdV, Boussinesq, and Kaup-Kuperschmidt Equations Based on Jacobi Polynomials

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    In this paper, a numerical method is developed to approximate the soliton solutions of some nonlinear wave equations in terms of the Jacobi polynomials. Wave are very important phenomena in dispersion, dissipation, diffusion, reaction, and convection. Using the wave variable converts these nonlinear equations to the nonlinear ODE equations. Then, the operational Collocation method based on Jacobi polynomials as bases is applied to approximate the solution of ODE equation resulted. In addition, the intervals of the solution will be extended using an rational exponential approximation (REA). The KdV, Boussinesq, and Kaup–Kuperschmidt equations are studied as the test examples. Finally, numerical computation of the conservation values shows the effectiveness and stability of the proposed method

    On-orbit Inter-satellite Radiometric Calibration of Cross-track Scanning Microwave Radiometers

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    This dissertation concerns the development of an improved algorithm for the inter-satellite radiometric calibration (XCAL) for cross track scanning microwave radiometers in support of NASA\u27s Global Precipitation Mission (GPM). This research extends previous XCAL work to assess the robustness of the CFRSL double difference technique for sounder X-CAL. In this work, using a two-year of observations, we present a statistical analysis of radiometric biases performed over time and viewing geometry. In theory, it is possible to apply the same X-CAL procedure developed for conical-scanning radiometers to cross-track scanners; however the implementation is generally more tedious. For example, with the cross-track scan angle, there is a strong response in the observed Tb due to changes in the atmosphere slant path and surface emissivity with the Earth incidence angle. For ocean scenes this is trivial; however for land scenes there is imperfect knowledge of polarized emissivity. However, for the sounder channels the surface emissivity is not the dominant component of top-of-the-atmosphere Tb, which is a mitigating factor. Also, cross-track scanners introduce changes in the radiometer antenna observed polarization with scan angle. The resulting observation is a mixture of un-polarized atmospheric emissions and vertical and horizontal polarized surface emissions. The degree of polarization mixing is known from geometry; however, reasonable estimates of the surface emissivity are required, which complicate over land comparisons. Finally, the IFOV size monotonically increases over the cross-track scan. Thus, when inter-comparing cross-track scanning radiometers, it will be necessary to carefully consider these effects when performing the double difference procedure

    Implementation of Multidomain Unified Forward Operators (UFO) Within the Joint Effort for Data Assimilation Integration (JEDI): Ocean Applications

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    The Joint Effort for Data assimilation Integration (JEDI) is a collaborative development led by the Joint Center for Satellite Data Assimilation (JCSDA) in conjunction with NASA, NOAA and the Department of Defense (NAVY and Air Force). The (Sea-Ice Ocean and Coupled Assimilation) SOCA as one of the JCSDA projects, focuses on the application of JEDI to marine data assimilation. One of the goals of SOCA is to make use of surface-sensitive radiances to constrain sea-ice and upper ocean fields (e.g., salinity, temperature, sea-ice fraction, sea-ice temperature, etc.). The first elements toward an ocean/atmosphere coupled data assimilation capability within JEDI, with a focus on supporting and developing the assimilation of radiance observations sensitive to the ocean and atmosphere has been implemented. The direct radiance assimilation of surface sensitive microwave radiances focusing on Global Precipitation Measurement (GPM) Imager (GMI) for the SST Constraint and Soil Moisture Active Passive (SMAP) for the Sea Surface Salinity (SSS) has been the main focus. Also, in UFO the capability to calculate the cool skin layer depth and skin temperature has been implemented similar to the GEOS-5. It has been tested with GMI sea surface temperature retrievals. This is important because Satellite and in-situ observations of the Sea-Surface Temperature (SST) show high variability, including a diurnal cycle and very thin, cool skin layer in contact with the atmosphere, and Incorporating a realistic skin SST is essential for atmosphere-ocean coupled data assimilation

    Impact Study of the Assimilation of Surface Sensitive Microwave Radiances in the GEOS

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    The aim of this study is to investigate the feasibility of assimilating low frequency microwave observations from different satellite Microwave radiometers such as the Advanced Microwave Sounding Unit-A (AMSU-A). These observations are relevant to the description of air temperature, humidity, and surface parameters such as ocean surface temperature. Their assimilation into Goddard Earth Observing System (GEOS) modeling and assimilation system helps better constrain models in regions where very few observations are assimilated. In recent years, Channels 14 and 15 have not been assimilated in GEOS because of their large sensitivities to uncertain surface parameters such as emissivity and skin temperature. Here, the impact of using different channels will be discussed. Also we investigate the validity of the emissivity model in these channels over ocean and sea ice.Radiative transfer calculations necessary for the assimilation of satellite radiances are performed using the Community Radiative Transfer Model (CRTM). The CRTM performs forward radiative transfer calculations of brightness temperature from atmospheric profiles (temperature, moisture, and ozone) and surface characteristics. Additionally, the CRTM calculates the Jacobians of brightness temperature with respect to the input . The Jacobians are for the inversion of these radiances within the Gridpoint Statistical Interpolation (GSI) analysis system. Here, For direct assimilation of the radiance observations, the interface between GSI and CRTM, is slightly modified. Finally, we validate the assimilation results, and discuss the impact of each channels in detail

    Comparison of the Effects of Media-based and Face-to-face Cardiac Rehabilitation Training Programs on Self-efficacy in Patients Undergoing Coronary Artery Bypass Grafting

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    Background: Several complications may occur in patients after coronary artery bypass grafting (CABG) leading to decreased self-efficacy. Rehabilitation training is the best method for reducing the complications and increasing self-efficacy. Various educational techniques lead to different rehabilitation results and levels of self-efficacy. Improving these measures requires the selection of the most appropriate educational technique. Aim: This study aimed to compare the effect of two media-based and face-to-face cardiac rehabilitation training methods on self-efficacy in patients undergoing CABG. Method: This clinical trial was conducted among 60 patients, who were randomly assigned into two groups, in Imam Reza Hospital, Mashhad, Iran, 2017. Cardiac rehabilitation training program was implemented face-to-face or using a researcher-made multimedia upon admission, discharge, at the start of cardiac rehabilitation, and at the end of the 10th session for half-hour. A researcher-constructed questionnaire on self-efficacy was completed by the participants in the mentioned stages. Data analysis was performed in SPSS software, version 16. Results: The mean ages of the participants in the face-to-face and multimedia groups were 56.0±8.1 and 57.5±7.3 years old, respectively. No significant difference was observed in the self-efficacy scores of the patients upon admission (P=0.36). However, there was a significant difference between the groups at the post-intervention stage (

    Relationship between platelet count and platelet width distribution and serum uric acid 1 concentrations in patients with untreated essential hypertension

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    Hematological parameters have emerged as independent determinants of high serum concentrations of uric-acid and predictive-factors in the evaluation of the total cardiovascular-risk in patients with essential-hypertensive. Here we have investigated the possible relationships between hematological-factors and serum uric-acid levels in hypertensive-patients recruited as part of Mashhad-Stroke and Heart-Atherosclerotic-Disorders cohort study. Two-thousand three-hundred and thirty four hypertensive individuals were recruited from this cohort and these were divided into two groups; those with either high or low serum uric acid concentrations. Demographic, biochemical and hematological characteristics of population were evaluated in all the subjects. Logistic-regression-analysis was performed to determine the association of hematological-parameters with hypertension. Of the 2334 hypertensive-subjects, 290 cases had low uric-acid, and 2044 had high serum uric acid concentrations. Compared with the low uric acid group, the patients with high serum uric acid, had higher values for several hematological parameters, whilst platelet counts (PLT) were lower. Multiple linear regression analysis showed that PLT and serum hs-CRP were correlated with serum uric acid level. Stepwise multiple logistic regression model confirmed that PDW and gender were independent determinant of a high serum uric acid. PDW and PLT appear to be independently associated with serum uric acid level in patients with hypertension

    Human immunodeficiency virus, hepatitis B virus, hepatitis C virus, and syphilis co-infections among patients with anogenital warts in Tabriz, Iran

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    Introduction: Genital infection with papilloma virus is the most common sexually-transmitted disease (STD). It is recommended that individuals who have a sexual risk factor, should be screened for syphilis, human immunodeficiency virus (HIV), and hepatitis B and C. However, this strategy is often not carried out in Iran. In the present study, patients with genital warts were screened for syphilis, HIV, and hepatitis B and C. Methods: We evaluated 311 patients with anogenital warts visiting dermatology clinics from June 2016 to June 2017. In addition, demographic data were collected using a pre-designed questionnaire. Patients who presented to Sina Hospital, Tabriz, Iran, were examined for HIV, syphilis, hepatitis B and C, urethral and vaginal discharge, and history of painful genital lesions, while patients presenting to Bahar Behavioral Disease Counseling Center of Tabriz were examined only for HIV. Data were analyzed using chi-square and Fisher’s exact tests via SPSS software. Results: Out of 263 cases with genital warts presenting to Sina Hospital, 1, 1, and 2 cases were positive for HIV, syphilis, and hepatitis B, respectively. At the same time, one of the patients presenting to Bahar Center showed HIV infection. Conclusion: We found two HIV-positive, two hepatitis B virus (HBV)-positive, and one syphilis cases in 311 patients with genital warts, so it is recommended to assess these tests routinely in high-risk individuals with genital warts, including multi-partner and addicted patients

    Evaluating The Association Between Serum Hsp27 Antibody and Hypertension in Patients without Underlying Cardiovascular Disease

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    Introduction: An association between heat shock protein 27 (Hsp27) antigen with cardiovascular risk factors has been shown previously. Furthermore, higher levels of serum anti-HSP27 antibodies are also related to higher cardiovascular morbidity and mortality. In the current study, we looked at the relationship between serum Hsp27 antibodies and hypertension, as an important cardiovascular risk factor, in individuals without evidence of cardiovascular disease (CVD).Methods: A sub-population of hypertensive patients (HTN+) without underlying CVD were recruited from the Mashhad stroke and atherosclerosis heart disease (MASHAD) study to assess the association between serum Hsp27 antibodies and hypertension; independent of other cardiovascular risk factors. A total of 1599 people were studied of whom 288 individuals had hypertension and 1311 were used as controls (HTN-).Results: Mean serum Hsp27 antibody titers were 0.20 (0.27) OD in the whole population sample and was not significantly different in the normotensive (HTN-) compared to HTN+ individuals with different degrees of hypertension.Conclusion: There were no significant associations between serum anti-Hsp27 concentrations and either the presence or severity of hypertension. Future studies are warranted to explore the association of anti-Hsp27 antibody and antigen levels and other cardiovascular risk factors

    The relationship between genetic variants associated with primary ovarian insufficiency and lipid profile in women recruited from MASHAD cohort study

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    Background and aim: Primary Ovarian Insufficiency (POI) is defined by the occurrence of menopause before the age of 40 years. It is often associated with cardiovascular disease (CVD). The purpose of this study was to explore the relationship between POI-associated genotypes cardiometabolic disorder risk factors. Methods: One hundred seventeen women with POI and one hundred eighty-three healthy women without POI were recruited in this study. DNA was extracted and analyzed using ASO-PCR or Tetra ARMS-PCR. Lipid profiles were also assessed. Results: Multivariate logistic regression analysis showed that individuals with GG vs. TT genotype of the rs1046089 SNP were more likely to have a higher serum LDL (p = 0.03) compared to the control group. There was also a significant association between low serum HDL and rs2303369 and rs4806660 SNP genotypes in the POI group. In the POI group, the percentage of those with high total cholesterol was lower in those with a CC genotype compared to those with a TT genotype (p = 0.03). Conclusion: Some SNPs reported to be associated with POI appear to be independently associated with dyslipidemia. These results may be helpful to identify subjects with POI who may be susceptible to CVD
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