9 research outputs found

    Monitoring Sand Drift Potential and Sand Dune Mobility over the Last Three Decades (Khartouran Erg, Sabzevar, NE Iran)

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    Aeolian sediments cover about 6% of the earth’s surface, of which 97% occur in arid regions, and these sediments cover about 20% of the world’s lands. Sand drifts can harm sensitive ecosystems; therefore, this research has aimed to study wind regimes and the monitoring of sand drift potential and dune mobility in the Khartouran Erg (NE Iran). The study investigated 30 years of wind speed and direction to better understand sand dune mobility processes using the Fryberger and Tsoar methods. The results of the wind regime study showed that the eastern (33.4%) and northeastern (14.3%) directions were more frequent, but the study of winds greater than the threshold (6 m/s) in winter, spring, and autumn indicated the dominance of eastern and northern wind directions. Findings of calm winds showed that winters (40.4%) had the highest frequency, and summers (15%) had the lowest frequency; the annual frequency was 30%. The average wind speed in summers was the highest (4.38 m/s), and, in the winters, it was the lowest (2.28 m/s); the annual average wind speed was 3.3 m/s. The annual drift potential (DP = 173 VU) showed that it was categorized as low class, and the winds carried sand to the southwest. The monitoring of drift potential showed that there was a sharp increase between 2003 and 2008, which could have been attributed to a change in wind speeds in the region. Unite directional index, the index of directional variability, has been alternating from 0.3 to 0.6 for 30 years. Furthermore, monitoring of sand mobility recorded a value from 0.1 to 0.4, and the lowest and highest values were registered from 0.08 to 0.9, with an average of 0.27. Finally, it can be concluded that sand dunes have been fixed for a long time, and the intensity of the mobility index is affected by climate changes

    Reviews in Clinical Medicine Ureteroscopic lithotripsy compared with extracorporeal shockwave lithotripsy in the treatment of urolithiasis ARTICLE INFO ABSTRACT

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    Keywords Extracorporeal shockwave lithotripsy Ureteroscopic surgery Urolithiasis Introduction: Urolithiasis is a common and frequently occurring disease with high recurrence rate. Ureteroscopic lithotripsy (URSL) and extracorporeal shock wave lithotripsy (ESWL) are two most popular modalities in the treatment of urolithiasis. The efficacy of these two methods is reviewed on the treatment of ureteral stones in this systematic review. Method: PubMed was searched for the relevant randomized control trials (RCTs). Stone-free rate and retreatment rate were extracted from each article as the main outcomes, and Odds ratio was reported in each study. Result: Based on calculated odds ratio of each article, URSL has an odds ratio of <1 for the event of stone-free rate, and odds ratio of >1 for the event of retreatment rate compared with ESWL. Discussion: Performing URSL in the treatment of urolithiasis could be associated with higher stone-free rate and lower retreatment rate; however duration of the surgery seems to be longer during URSL compared with ESWL. Conclusions: There was high discrepancy between included RCTs regarding the study design, stone location, types of ureteroscope, intracorporeal lithotripsy devices, time to follow-up, and surgeon experience, which might affect the decision regarding type of surgery. Please cite this paper as: Asl Zare M, Darab Mahboob MR, Rahdari R. Ureteroscopic lithotripsy compared with extracorporeal shockwave lithotripsy in the treatment of urolithiasis. Rev Clin Med. 2016;3(2):48-52

    Ureteroscopic lithotripsy compared with extracorporeal shockwave lithotripsy in the treatment of urolithiasis

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    Introduction: Urolithiasis is a common and frequently occurring disease with high recurrence rate. Ureteroscopic lithotripsy (URSL) and extracorporeal shock wave lithotripsy (ESWL) are two most popular modalities in the treatment of urolithiasis. The efficacy of these two methods is reviewed on the treatment of ureteral stones in this systematic review. Method: PubMed was searched for the relevant randomized control trials (RCTs). Stone-free rate and retreatment rate were extracted from each article as the main outcomes, and Odds ratio was reported in each study.Result: Based on calculated odds ratio of each article, URSL has an odds ratio of 1 for the event of retreatment rate compared with ESWL.Discussion: Performing URSL in the treatment of urolithiasis could be associated with higher stone-free rate and lower retreatment rate; however duration of the surgery seems to be longer during URSL compared with ESWL.Conclusions: There was high discrepancy between included RCTs regarding the study design, stone location, types of ureteroscope, intracorporeal lithotripsy devices, time to follow-up, and surgeon experience, which might affect the decision regarding type of surgery

    International Journal of Farming and Allied Sciences The nature and origin of sand dunes in Kashan ERG, Iran

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    ABSTRACT: Wind erosion is a process of wind-forced movement of soil particles. This process has the distinct phases of particle entrainment, transport and deposition. Because Iran locate in area that is sensitive about geological and climatic factors makes ERG in deposition phase that scattered in nineteen areas of Iran and they are included more than two Percent of it. Kashan ERG is very importance region in central of Iran about living, agriculture and industry then identifying of nature and origin of sand dunes is very important. In this study for identified and separated of detachment area used from interpretation of aerial photographs, satellite images and field operations. Finally, fifty samples were transferred to the laboratory for granulometric, mineralogical and morphoscopy tests. Results show that the study area belongs to the Cenozoic and include in marne and shale as well as region forms from many facies. Analysis of wind data show that the final orientation of sand transport in Kashan ERG is from southwest and west to northeast and north. And water in height region is more Carbonate as well as in low region carbonate to sulfate and in playa region is sulfate to Chlorin. Morphoscopy test proves that the origin of sands is in the water flows so sands in Kashan area do not have a very distant geological origin. Sand dunes are located at an altitude of 800 to 950 meter in region. In general, the sand dunes in north and north-west region of Kashan are in SSE-NNW and in east is SSW-NNE until NE-SW eventually in north is in NS direction. Basic density of the sand in the area shows irregularly handle funnel-shaped

    Assessment of the Sustainability of the Territories Affected by Gully Head Advancements through Aerial Photography and Modeling Estimations: A Case Study on Samal Watershed, Iran

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    Gully erosion is considered one of the major issues of land sustainability because it can remove considerable volumes of sediment and productive soils. Once started, gullies can continue to move by headcut retreat, or slumping of the side walls. Studies of gully development require constant monitoring activities which are not possible in not-well-explored areas, such as the arduous region of Iran, due to costs and a lack of geoinformation. Thus, the present research attempts to assess gully evolution using only two digital aerial photographs of different periods (1968 and 1994) and field assessment (2009) to estimate the gully head advancement based on frames geometry and rigorous procedure in southwestern Iran. Also, the gully head advancement was estimated and compared among them by different empirical equations. The results indicated that the mean of gully head advancement was 1.4 m year−1 and 1.2 m year−1 during 1968–1994 and 1994–2009, respectively, and the annual average of sediment mobilization was 26.8 m3 ha−1 in 2009. The model assessment indexes indicated that SCS (Soil Conservation Service) II was the best model for gully head advancement estimations in this study area. The main reasons for this can be associated with the Rp factor (previous gully head advancement) and the local environmental conditions. We conclude that the sustainability of the territory has been greatly affected due to this advancement. We also hypothesize that gully head changes could be related to the susceptibility of geological formations, climate, soil properties, and the coincidence of other gullies’ formation with common drainage networks in the study area. Based on the obtained results, land managers can use the results to distinguish the gullies in this region with a higher environmental risk, and to decide an effective implementation of soil conservation measures in order to include them in the land management plans

    Soil erosion modelling: a global review and statistical analysis

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    To gain a better understanding of the global application of soil erosion prediction models, we comprehensively reviewed relevant peer-reviewed research literature on soil-erosion modelling published between 1994 and 2017. We aimed to identify (i) the processes and models most frequently addressed in the literature, (ii) the regions within which models are primarily applied, (iii) the regions which remain unaddressed and why, and (iv) how frequently studies are conducted to validate/evaluate model outcomes relative to measured data. To perform this task, we combined the collective knowledge of 67 soil-erosion scientists from 25 countries. The resulting database, named ‘Global Applications of Soil Erosion Modelling Tracker (GASEMT)’, includes 3030 individual modelling records from 126 countries, encompassing all continents (except Antarctica). Out of the 8471 articles identified as potentially relevant, we reviewed 1697 appropriate articles and systematically evaluated and transferred 42 relevant attributes into the database. This GASEMT database provides comprehensive insights into the state-of-the-art of soil- erosion models and model applications worldwide. This database intends to support the upcoming country-based United Nations global soil-erosion assessment in addition to helping to inform soil erosion research priorities by building a foundation for future targeted, in-depth analyses. GASEMT is an open-source database available to the entire user-community to develop research, rectify errors, and make future expansions.</p

    Soil erosion modelling: a bibliometric analysis

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    Soil erosion can present a major threat to agriculture due to loss of soil, nutrients, and organic carbon. Therefore, soil erosion modelling is one of the steps used to plan suitable soil protection measures and detect erosion hotspots. A bibliometric analysis of this topic can reveal research patterns and soil erosion modelling characteristics that can help identify steps needed to enhance the research conducted in this field. Therefore, a detailed bibliometric analysis, including investigation of collaboration networks and citation patterns, should be conducted. The updated version of the Global Applications of Soil Erosion Modelling Tracker (GASEMT) database contains information about citation characteristics and publication type. Here, we investigated the impact of the number of authors, the publication type and the selected journal on the number of citations. Generalized boosted regression tree (BRT) modelling was used to evaluate the most relevant variables related to soil erosion modelling. Additionally, bibliometric networks were analysed and visualized. This study revealed that the selection of the soil erosion model has the largest impact on the number of publication citations, followed by the modelling scale and the publication's CiteScore. Some of the other GASEMT database attributes such as model calibration and validation have negligible influence on the number of citations according to the BRT model. Although it is true that studies that conduct calibration, on average, received around 30% more citations, than studies where calibration was not performed. Moreover, the bibliographic coupling and citation networks show a clear continental pattern, although the co-authorship network does not show the same characteristics. Therefore, soil erosion modellers should conduct even more comprehensive review of past studies and focus not just on the research conducted in the same country or continent. Moreover, when evaluating soil erosion models, an additional focus should be given to field measurements, model calibration, performance assessment and uncertainty of modelling results. The results of this study indicate that these GASEMT database attributes had smaller impact on the number of citations, according to the BRT model, than anticipated, which could suggest that these attributes should be given additional attention by the soil erosion modelling community. This study provides a kind of bibliographic benchmark for soil erosion modelling research papers as modellers can estimate the influence of their paper
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