To obtain the distribution of the Love wave group velocities in northwest Iran and its surrounding areas for 7, 10, 20 and 25 second periods, the waveform of 241 local and regional events used in a DISPERSION CURVE tomography of the Love waves. The evnets occurred within NW Iran and surrounding areas between 2005 and 2015 and were recorded by 39 permanent and temporary medium and broad band seismic stations belonging to national and international seismic networks. In order to reduce the effect of non-uniform distribution of events, we selected the more uniform list of events out of an initial number of 1734 non-uniform distributed events. We applied the Frequency-Time Analysis method to each event-station path for estimation of Love wave group velocities, then we used a tomographic method to compute the distribution of local group velocities throughout the region. From the analysis of the surface wave tomography, we concluded that crustal structure in the South Caspian Basin and the Kura Depression is almost the same, but it is significantly different from that of the northwest Iran. In the presence of thick and low shear velocity sediments in the South Caspian Basin, we observed low velocity anomalies at periods less than 10 seconds that are surrounded by relatively higher velocities along Alborz, Talesh and Lesser Caucasus. In the “ Eastern Anatolian Accretionary Complex” where volcanic activities are much higher than in rest of the region, less group velocities were observed for periods less than 25 seconds. The main reason for this observation can be related to the presence of partial melting zones inside the crust as a result of intensive volcanic activities in this region. In Zagros, for the periods of 7 and 10 seconds, a relatively high velocity anomaly along the “ Sanandaj-Sirjan” metamorphic zone was observed, which was trapped by two low velocities along the “ Zagros Folding and Thrust Belt” in one side and “ Urmieh-Dokhtar Magmatic Arc” in another side. The active and broken crust, reverse, active and shallow thrust faults and high seismicity of Zagros Folding and Thrust Belt is characterized by low group velocities in our results for periods of less than 25 seconds. In most areas of central Iran and Urmieh-Dokhtar Magmatic Arc, local sedimentary basins are characterized by low velocities for periods of 7 and 10 seconds. Our results indicate that crustal structure in the northwest of Iran is almost uniform and has the minimum changes, but it is completely different from the crustal structure in the South Caspian Basin, eastern Turkey, and the Zagros mountains.

One of the most interesting topics in the geotechnical and geophysical engineering is the use of surface waves to characterize the earth subsurface layers. In a vertically heterogeneous media, the phase velocity of the surface wave is a function of the frequency (the frequency-phase velocity relationship is called DISPERSION CURVE). The DISPERSION CURVE is calculated by the shear wave velocity, compressive velocity, density, and thickness of each of the layers, which their properties can be increasing or decreasing from the surface to the half-space. In this paper, horizontal soil layers were modelled using finite element method based software (ABAQUS). Due to the different layering specifications, the models are divided into two main types: the layers’ characteristics increase with depth and the layers' characteristics decrease and increase with depth. An active impact source was used to create surface waves and the absorption layers with increasing damping (ALID) were applied to the model boundaries to prevent the wave reflection. Based on the gathered surface wave data, the DISPERSION CURVE was plotted using Frequency-Wavenumber Transfer method. In addition, the effects of different geophone offsets on the DISPERSION CURVE were investigated. The results showed that using the DISPERSION CURVE and phase velocity at high frequencies, the thickness of the surface layer can be calculated. Also, the slope of the DISPERSION CURVE at low frequencies indicates the number of the layers at different properties, and the steeper and closer to the vertical, means that a few number of layers are exist in the media. Furthermore, the effects of different geophone offsets were investigated and it was observed that geophone offsets should be limited to less than one-fourth of the layer depth in order to prevent the DISPERSION CURVE jumping to the higher modes. Furthermore, if the DISPERSION CURVE jumps to the higher modes at high frequencies, seismic data can be taken at a less geophones’ offset or the DISPERSION CURVE frequency range limitation is only before jumping to higher modes.

Background and Objectives: Organic matter improves the physical condition of the soil and due to the increase in water holding capacity of the soil, changes the pattern of contaminant uptake and prevents them from leaching into groundwater. DISPERSION is important factor affecting soil solute transport in porous media that used in the advection-DISPERSION equation and it is a function of the transmission distance. The aim of this study was to investigate the effect of biochar on the leaching process of deltamethrin in soil columns. During this study, the Breakthrough CURVE and DISPERSION coefficient of this pesticide in vertical soil columns were determined. Materials and Methods: This study was carried out in soil columns with a height of 15 and 30 cm and in a period of 12, 23, 56 and 112 days and including different levels of 1. 5 and 3 WP% (Weight percent) of wheat biochar and control treatment as a completely randomized factorial design. The concentration of deltamethrin used was 300 cc per thousand liters per hectare. To determine the residual concentration, the pesticide was sprayed on the surface only once with the recommended dose and according to the considered irrigation periods, the changes of the pesticide over time and at different depths of the soil columns were studied. In this study, Brigham's analytical method was used to obtain the DISPERSION coefficient. Analysis of variance and comparison of means in the studied treatments was performed using LSD statistical test and SAS 9. 4 software. Results: The results showed that the residual concentrations of pesticides in 1. 5 and 3% of biochar treatments compared to the control were decreased 26 and 43%, at depths of 0-15 cm and 37 and 17% at depths of 15-30 cm respectively. Based on the results, pesticide uptake and stabilization in 3% biochar treatment was more than other treatments. In the control treatment, with increasing soil depth, it was observed that the DISPERSION coefficient decreased, in the modified treatment with biochar 1. 5%, the DISPERSION increased while in the biochar 3% treatment, the DISPERSION coefficient decreased significantly by increasing the sample length. Deltamethrin DISPERSION coefficient in 15 cm columns for control, biochar 1. 5 and 3% treatments were 5. 37, 1, 3. 59 cm and in 30 cm columns 3. 91, 1. 27, 0. 92 cm was obtained, respectively. Conclusion: Biochar production is very convenient and cost-effective and is successful in restricting the movement and stabilization of pesticides in the soil and by increasing its weight percentage in the soil, due to the surface area of biochar can control the movement of pesticides.

Background: Nocturnal hypoxia is an important factor increasing the risk of mortality in patients with chronic heart failure and is associated with atrial and ventricular arrhythmias. QT DISPERSION, an index of myocardial electrical activity, is used as a prognostic tool in determining future malignant arrhythmias and sudden cardiac death. In the current study we investigated the effect of nocturnal oxygen therapy (NOT) on QTd in patients with CHF.Materials and methods: In this clinical study 54 patients with CHF (EF≤40%) were enrolled. Patients were administered NOT; electrocardiography was taken before and after NOT and QTd measured each time. Paired t-test was used to compare pre- and post-NOT QTd.Results: QTd significantly decreased from 56.3±18.2 msec before NOT to 46.3±17 msec after NOT (p=0.001).Conclusion: In this study NOT decreased QTd in patients with CHF which could consequently decrease risk of malignant arrhythmias and sudden cardiac death. However, the mechanisms by which NOT decreases QTd is not clear and requires further investigation.

Introduction: Sudden cardiac death is common in patients on hemodialysis and may occur in the immediate post dialysis period when ventricular premature complexes are common. QT DISPERSION reflecting hetovogelity in ventricle repolarization has been used for predicting patients with risk of malignant arrhythmia and sudden death. The purpose of the study was to assess the effect of hemodialysis on QT DISPERSION (QTd) corrected QT DISPERSION (QTcd) and maximum QTc (QTcMax) in chronic hemodialysis patients. Methods: In this deh1ive-analytic study data of 48 patients (30 male and 18 female patients with mean age 43±16 yr) on chronic hemodialysis were studied. 12 lead ECG were recorded 5-10 minutes before and after hemodialysis in a standard setting and Na+ K+ Ca++ Po4 and Mg++ levels were also determined pre and post hemodialysis. During hemodialysis no drug therapy was used except isotonic and hypertonic NaCl infusions and sodium heparin. The maintenance drug therapy including digitalis antihypertensive antianginal and beta blocking agents was not changed. The data were analyzed using SPSS software. Results: The maximal QTd interval changed significantly from 434±12.8 ms to 443±21.33 ms (P<0.001). The QTd increased significantly from 55.87±7.5 ms to 61.27±9.09 ms (p<0.001) and QTcd from 61.18±43 ms to 68.79±10.32 ms (p<0.001). 33.33% of the patients before and 47.90% after hemodialysis had QTcMax more than 440 ms.Conclusion: Hemodialysis incrases the QTd, QTcd and QTcMax in patients with end-stage renal failure, Tuse it is likely that heterogeneity of regional ventricular repolarization increases during hemodialysis.