84 research outputs found
Digital soil mapping, downscaling and updating conventional soil maps using GIS, RS, statistics and auxiliary data
Spatial distribution of soil types and soil properties in the landscape are important in many environmental researches. Conventional soil surveys are not designed to provide the high-resolution soil information required in environmental modelling and site-specific farm management. The objectives of this study were to investigate the relationship between soil development, soil evolution in the landscape, updating legacy soil maps and pedodiversity in an arid and semi-arid region. The application of Digital Soil Mapping (DSM) techniques was investigated with a particular focus to predict soil taxonomic classes and spatial distribution of soil types by soil observations and covariate sets representative of s,c,o,r,p,a,n factors.
In the first study, focus is on establishing relationships between pedodiversity and landform evolution in a 86,000 ha region in Borujen, Chaharmahal-Va-Bakhtiari Province, Central Iran. From an overview study, we could conclude that landform evolution was mainly affected by topography and its components.
A second study compares various DSM-methods and a conventional soil mapping approach for soil class maps in terms of accuracy, information value and cost in central Iran. Also, the effects of different sample sizes were investigated. Our results demonstrated that in most predicted maps, in DSM approaches, the best results were obtained using the combination of terrain attributes and the geomorphology map. Furthermore, results showed that the conventional soil mapping approach was not as effective as DSM approach.
In the third study, different models of the DSM approach were compared to predict the spatial distribution of some important soil properties such as clay content, soil organic carbon and calcium carbonate content. Among all studied models, the terrain attribute “elevation” is the most important variable to predict soil properties. Random forest had promising performance to predict soil organic carbon. But results revealed that all models could not predict the spatial distributions of clay content properly.
The minimum area of land that can be legibly delineated in a traditional (printed) map is highly dependent upon mapping scale. For example, this area at a mapping scale of 1:24,000 is about 2.3 ha but at a mapping scale of 1:1,000,000 it is about 1000 ha. A mapping scale of 1:1,000,000 is just too coarse to show a fine-scale pattern or soil type with any degree of legibility, but finer-scale soil maps are more expensive and time-consuming to produce. Thus, spatial variation is often unavoidably obscured. The fourth study of this dissertation focuses on downscaling and updating soil map methods. Thus, the objectives were to apply supervised and unsupervised disaggregation approaches to disaggregate soil polygons of conventional soil map at a scale of 1: 1,000,000 in the selected area. Therefore, soil subgroups and great groups were selected because it is a basic taxonomic level in regional and national soil maps in Iran.
In general, we conclude that DSM approach and also disaggregation approach are capable to predict soil types and properties, produce and update legacy soil maps. However, still a number of challenges need to be evaluated e.g. influence of expert knowledge on CSM approach, resolution of ancillary data, georeferenced legacy soil samples data to validate disaggregated soil maps
Rational design and expeditious synthesis of aromatic cyanodienone derivatives assisted by cyanide-halide exchange
1-n-Butyl-3-methylimidazolium cyanide ([bmim]CN), in the presence of [bmim]Br has been prepared and used for the first time as the medium as well as reagent for the synthesis of aromatic cyanodienones from the corresponding triarylpyrylium perchlorates by cyanide-halide exchange. The [bmim]CN having a reactive anion, accelerated reaction technique without external solvent renders the whole synthesis into a truly ecofriendly protocol. The products is isolated without aqueous work-up in high purity and excellent yield.
Rational design and expeditious synthesis of aromatic cyanodienone derivatives assisted by cyanide-halide exchange
1-n-Butyl-3-methylimidazolium cyanide ([bmim]CN), in the presence of [bmim]Br has been prepared and used for the first time as the medium as well as reagent for the synthesis of aromatic cyanodienones from the corresponding triarylpyrylium perchlorates by cyanide-halide exchange. The [bmim]CN having a reactive anion, is an accelerated reaction technique without external solvent and renders the whole synthesis into a truly eco-friendly protocol. The products can be isolated without aqueous work-up in high purity and excellent yield.
Rational design and expeditious synthesis of aromatic cyanodienone derivatives assisted by cyanide-halide exchange
1027-10301-n-Butyl-3-methylimidazolium cyanide ([bmim]CN), in the presence of [bmim]Br has been prepared and used for thefirst time as the medium as well as reagent for the synthesis of aromatic cyanodienones from the corresponding triarylpyrylium perchlorates by cyanide-halide exchange. The [bmim]CN having a reactive anion, is an accelerated reaction technique without external solvent and renders the whole synthesis into a truly eco-friendly protocol. The products can be isolated without aqueous work-up in high purity and excellent yield
The appearance of place identity in the urban landscape by using the natural factors (a case study of Yasouj)
This study has examined the effects of natural factors (urban landscape) on the place identity. In order to perform this, the place identity has been measured and also its relationship with the components of natural factors, absolute elements, living elements and natural elements have been measured. The study is descriptive and the statistical population has been Yasouj which is a city in Iran. To analyze the data the SPSS software has been used. The results have been investigated in two levels of descriptive and inferential statistics. In the inferential statistics, Pearson correlation coefficient has been used to evaluate the research hypotheses. In this study, the variable of place identity is in high level and the natural factors are also in high level which these results indicate a positive relationship between place identity and natural factors. The results indicate that natural factors have significant role on Yasouj landscape and also increase the place identity. It can be inferred that the development of natural factors and reaching it to the qualified level will develop the place identity
Developing global pedotransfer functions to estimate available soil phosphorus
There are a large number of investigations that estimate available soil phosphorous (P), but a paucity of global data on available soil P. One significant modern challenge is developing low cost, accurate approaches to predict available soil P that are useful to scientists around the world. We conducted a global meta-analysis using data on available soil P from 738 sites, 640 in the USA and 149 in 14 other countries. Four different methods of determining available soil P, New Zealand (NZ), acid oxalate, Bray and Mehlich 3 were represented in the dataset. Inputs evaluated for inclusion in the pedotransfer functions to predict available soil P were clay (C), fine silt, (FSi) coarse silt (CSi), very fine sand (VFS), fine sand (FS), medium sand (MS), coarse sand (CS), very coarse sand (VCS), organic carbon (OC), pH, calcium (Ca), magnesium (Mg), potassium (K), iron (Fe), aluminum (Al), and manganese (Mn). Available soil P was estimated for: 1) the entire dataset, 2) only the USA, and 3) the non-USA dataset. The best models to estimate available soil P were obtained for the NZ method (using the co-variates C, FSi, CSi, VFS, MS, CS, OC, Fe, Al, Mn, Ca, Mg, and pH) and for the acid oxalate method (using the co-variates C, FSi, Fe, Al, Mn, Ca, and Mg). Although estimation of available soil P determined with the acid oxalate method was poor for the entire dataset, good estimates were obtained for the USA and non-USA datasets separately. Models for the Bray and Mehlich 3 methods only predicted available soil P well for the non-USA dataset. Using pedotransfer function models to estimate available soil P could provide an efficient and cost effective way to estimate global distributions of a soil property that is important for a number of agricultural and environmental reasons
Risk factors associated with long covid syndrome: A retrospective study
Background: Recently, people have recognized the post-acute phase symptoms of the COVID-19. We investigated the long-term symptoms associated with COVID-19, (Long COVID Syndrome), and the risk factors associated with it. Methods: This was a retrospective observational study. All the consecutive adult patients referred to the healthcare facilities anywhere in Fars province from 19 February 2020 until 20 November 2020 were included. All the patients had a confirmed COVID-19 diagnosis. In a phone call to the patients, at least three months after their discharge from the hospital, we obtained their current information. The IBM SPSS Statistics (version 25.0) was used. Pearson Chi square, Fisher’s exact test, t test, and binary logistic regression analysis model were employed. A P value of less than 0.05 was considered to be significant. Results: In total, 4,681 patients were studied, 2915 of whom (62.3%) reported symptoms. The most common symptoms of long COVID syndrome were fatigue, exercise intolerance, walking intolerance, muscle pain, and shortness of breath. Women were more likely to experience long-term COVID syndrome than men (Odds Ratio: 1,268; 95% Confidence Interval: 1,122-1,432; P=0.0001), which was significant. Presentation with respiratory problems at the onset of illness was also significantly associated with long COVID syndrome (Odds Ratio: 1.425; 95% Confidence Interval: 1.177-1.724; P=0.0001). A shorter length of hospital stay was inversely associated with long COVID syndrome (Odds Ratio: 0.953; 95% Confidence Interval: 0.941-0.965; P=0.0001). Conclusion: Long COVID syndrome is a frequent and disabling condition and has significant associations with sex (female), respiratory symptoms at the onset, and the severity of the illness
Assessing the Influence of Soil Quality on Rainfed Wheat Yield
Soil quality assessment based on crop yields and identification of key indicators of it can be used for better management of agricultural production. In the current research, the weighted additive soil quality index (SQIw), factor analysis (FA), and multiple linear regression (MLR) are used to assess the soil quality of rainfed winter wheat fields with two soil orders on 53.20 km2 of agricultural land in western Iran. A total of 18 soil quality indicators were determined for 100 soil samples (0–20 cm depth) from two soil orders (Inceptisols and Entisols). The soil properties measured were: pH, soil texture, organic carbon (OC), cation exchange capacity (CEC), electrical conductivity (EC), soil microbial respiration (SMR), carbonate calcium equivalent (CCE), soil porosity (SP), bulk density (BD), exchangeable sodium percentage (ESP), mean weight diameter (MWD), available potassium (AK), total nitrogen (TN), available phosphorus (AP), available Fe (AFe), available Zn (AZn), available Mn (AMn), and available Cu (ACu). Wheat grain yield for all of the 100 sampling sites was also gathered. The SQIw was calculated using two weighting methods (FA and MLR) and maps were created using a digital soil mapping framework. The soil indicators determined for the minimum data set (MDS) were AK, clay, CEC, AP, SMR, and sand. The correlation between the MLR weighting technique (SQIw-M) and the rainfed wheat yield (r = 0.62) was slightly larger than that the correlation of yield with the FA weighted technique (SQIw-F) (r = 0.58). Results showed that the means of both SQIw-M and SQIw-F and rainfed wheat yield for Inceptisols were higher than for Entisols, although these differences were not statistically significant. Both SQIw-M and SQIw-F showed that areas with Entisols had lower proportions of good soil quality grades (Grades I and II), and higher proportions of poor soil quality grades (Grades IV and V) compared to Inceptisols. Based on these results, soil type must be considered for soil quality assessment in future studies to maintain and enhance soil quality and sustainable production. The overall soil quality of the study region was of poor and moderate grades. To improve soil quality, it is therefore recommended that effective practices such as the implementation of scientifically integrated nutrient management involving the combined use of organic and inorganic fertilizers in rainfed wheat fields should be promoted.publishedVersio
EFL Learners’ Vocabulary Achievement and Autonomy: Using Memrise Mobile Application
There has been rapid advancement in the use of technology through which an extensive array of mobile technologies have been introduced to educational contexts. In the same vein, mobile assisted language learning provides new possibilities for improving language learning conditions. The current study was an attempt to find out the effect of Memrise Mobile Application on Iranian upper-Intermediate EFL learners’ vocabulary achievement and their autonomy. To find the effects, a pre-test post-test quasi-experimental study was conducted. Fifty participants were selected from a cluster of 110 students. The Quick placement test as a test of homogeneity was administered to select the upper intermediate learners. Accordingly, 25 participants for each of the experimental and control groups were selected. Memrise Mobile Application was employed during the treatment period for teaching the 504 Absolutely Essential Words book to the experimental group while the control group was instructed the textbook of 504 Absolutely Essential Words. The intervention continued for a period of 8 weeks. A researcher-made vocabulary test and Zhang and Li’s (2004) standardized questionnaire on autonomy were administered. For the qualitative data collection, a semi-structured interview was conducted to determine the participants’ attitudes. An Independent T-test was run the results of which revealed a significant difference between the two groups in vocabulary achievement. However, there was no significant difference between the two groups in autonomy. Moreover, based on the qualitative data it was concluded that the experimental group participants were more motivated holding a more positive attitude
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