Vegetation change detection and soil erosion risk assessment modelling in the Man River basin, Central India

Land use change directly increased soil erosion risk, which is a very sensitive environmental issue in Central India. To evaluate the response of land use changes on soil erosion risk, research was implemented using remote sensing techniques, coupled with ground information, to develop an integrated modelling approach to study the factors driving land use changes in the Man River basin, Central India. Results were used to assess the impact of land use change on soil erosion risk. First, a series of sub methods were applied to monitor and verify land use land cover change in the study area which included pre-processing, classification and assessment of land use transaction from 1971 to 2013 using Landsat time series imagery. Additionally, an independent spatial assessment of deforestation, forest degradation and responsible drivers for the period 2009-2013 was conducted to enable a deeper analysis of forestry activates using the GIS based direct interpretation approach. The research also developed a robust accuracy assessment method to check the quality of the 2009 and 2013 classification maps using good quality Google Earth TM imagery and a field measured GPS dataset. These approaches were largely based on the GOFC- GOLD (2010) and IPCC good recommendations for land use land cover mapping and verification. The information obtained from an accuracy assessment was also used to estimate deforestation area and construct confidence intervals that reflect the uncertainty of the area estimates obtained. Such analysis is rarely applied in current published verification assessments. In the second phase of the study, a Geo-spatial interface for process-based Water Erosion Prediction Project (GeoWEPP) was implemented, to estimate the response of land use and land cover change on soil erosion risk in several scenarios derived from both ground and satellite based precipitation, DEMs and vegetation change. GeoWEPP was used at the hillslope scale in three selected watersheds within the Man River basin using Landsat, LISSIII, Cartosat-1, ASTER, SRTM, TRMM and ground based datasets. The results highlight that the study developed a realistic approach using remote sensing techniques to understand the pattern and process of landscape change in the Man River basin and its response on soil erosion risk. Over the last four decades, forest and agriculture areas were found to be the most dynamic land use /land cover categories. During the last four decades, around 54200 ha (33.7 %) forest area has been decreased due to the expansion of agriculture, forest harvesting and infrastructure development. The direct interpretation approach estimated similar patterns of deforestation and forest degradation associated with iii drivers for the 2009 to 2013 time period, but this approach also provided more accurate and location specific information than automatic analysis. The overall correspondence between the map and reference data are a good measure for 2009 and 2013; 94.03 % and 92.8 % respectively. User‘s and producer‘s accuracies of individual classes range from 75 % to 99 %. Using the accuracy assessment data and a simple set of equations, an error-adjusted estimate of the area of deforestation was obtained (± 95% confidence interval) of 23382 ± 550 ha. The estimated average annual soil loss for all three watersheds is 21 T/ha which was found to be comparable to similar studies carried out in the study region. The highest soil loss rates occurred in areas of agriculture (301 T. /ha /yr) and fallow land (158 T/ha/yr), while the lowest rates were recorded in forest land (33.45 T/ha/yr). Agriculture extension (316.5 ha) due to forest harvesting (234 ha) in the last four decades is one of the significant drivers to speed up soil erosion (7.37 T/ha/yr.) in all three watersheds. The spatial pattern of erosion risk indicates that areas with forest cover have minimum rates of soil erosion, while areas with extensive human intervention such as agriculture and fallow land, have high estimated rates of soil erosion. The different DEMs generated varied topographic and hydrologic attributes, which in turn led to significantly different erosion simulations. GeoWEPP using Cartosat-1 (30 m) and SRTM (90 m) produced the most accurate estimation of soil loss which was close to similar already published studies in the area. TRMM rainfall data has good to use as a rainfall parameter for soil erosion risk mapping in study area. Overall, the integrated approach using remote sensing and GIS allowed a clear understanding of the factors that drive land use/land cover change to be developed and enabled the impact of this change on soil erosion risk in the Man River basin, Central India to be assessed

Experimental Study on Geocell-Reinforced Recycled Asphalt Pavement (RAP) Bases under Static and Cyclic Loading

Recycled Asphalt Pavement (RAP) is a removed and reprocessed pavement material containing asphalt and aggregates which can be used as a base course material for pavement applications. Geocells are a three-dimensional interconnected honeycomb type of geosynthetics used to reinforce weak soils and base courses of roads and are ideal for soil confinement. The objectives of this study are to evaluate characteristics of milled recycled asphalt pavement (RAP) collected from a city street in Lawrence, Kansas and to investigate the creep and cyclic behavior of geocell-reinforced RAP bases over rigid subgrade under static loading and over weak subgrade under cyclic loading through laboratory testing respectively. The compaction and CBR curves were obtained for the RAP. The Mohr-Coulomb failure envelopes for RAP and RAP/geocell interface were obtained by direct shear tests. The asphalt binder and the aggregates were extracted from RAP. The extracted aggregates were tested for their properties including gradation, specific gravity, and fine aggregate angularity (FAA). The viscosity of the extracted asphalt binder was also determined. The results indicated that the asphalt content obtained by the ignition method was slightly higher than that by the centrifuge method. Gradation results indicated that the compaction did not change the gradation of the RAP. Fourteen medium-scale laboratory static plate loading tests were conducted on RAP samples under two vertical stresses at different confining conditions to investigate the creep deformation behavior of geocell-reinforced RAP bases. The creep axial strains at different time were estimated for RAP at different confining conditions and vertical stresses. The results indicated that the geocell confinement significantly reduced the initial deformation and the rate of creep of the RAP bases. Six medium-scale plate loading tests at different confining conditions and one unconfined compression test were conducted on RAP samples by applying static loads in increment to understand the pressure-displacement response and evaluate the bearing capacity and stiffness of the unreinforced and geocell-reinforced RAP bases. The results indicated that geocell significantly increased the bearing capacity and stiffness of RAP bases. Nine large-scale laboratory cyclic plate loading tests were conducted on RAP base sections with three different base course thicknesses. The novel polymeric alloy (NPA) geocells were used to reinforce the RAP bases. The behavior of unpaved RAP bases, such as permanent deformation, percentage of elastic deformation, stress distribution, and strains in the geocell walls was investigated. The results indicated that the geocell effectively reduced permanent deformation, and vertical stress at the interface of base and subgrade and increased the stress distribution angle and increased percentage of elastic deformation. The strain measurements demonstrated that the geocell-reinforced RAP bases behaved as a slab

Geocell-Reinforced Unpaved and Paved Roads with Recycled Asphalt Pavement (RAP) Bases: Experimental Study and Damage Model Development

Recycled Asphalt Pavement (RAP) is a removed and reprocessed pavement material from deteriorated asphalt pavements containing asphalt binder and aggregates. The use of RAP can reduce the cost of construction materials, reduce the amount of waste to be land-filled, and conserve natural resources by requiring less virgin aggregate and asphalt in road construction projects. Literature showed that RAP bases had more permanent deformation under static and dynamic loading compared to conventional aggregate base. Geocell is one type of geosynthetic products manufactured in a form of three-dimensional interconnected honeycomb shape polymeric cells. Geocell was used in this study to reinforce RAP bases in unpaved and paved roads. The objective of this study is to understand the behavior of unpaved and paved roads with unreinforced and geocell-reinforced RAP bases. Fifteen large-scale laboratory cyclic plate loading tests were conducted on unpaved and paved road sections with unreinforced or geocell-reinforced RAP bases. The unpaved road sections consisted of unreinforced or geocell-reinforced RAP bases over weak or moderate (target CBR = 2% or 5%) subgrade, whereas paved road sections consisted of hot mix asphalt (HMA) surface over unreinforced or geocell-reinforced RAP bases over moderate (target CBR = 5%) subgrade to investigate their performance and shake down responses under cyclic loading. The test results showed that geocell improved the performance of RAP bases as compared with the unreinforced bases by increasing the percentage of resilient deformation and reducing the permanent deformations and the vertical stresses transferred to the subgrade. A thin (about 50 mm) HMA surface significantly improved the performance of RAP bases. The thicker geocell-reinforced RAP base behaved as a slab with bending resistance and the thinner base behaved as a slab initially at a smaller deformation and then as a tensioned membrane at a larger deformation. The geocell-reinforced RAP bases showed a stable shakedown response whereas the unreinforced RAP base showed an unstable shakedown response. Based on cyclic plate loading test results, damage models for the empirical correlation between the permanent strain and/or the resilient strain with the number of loading cycles were developed for unpaved and paved roads including unreinforced and geocell-reinforced RAP bases. The mechanistic empirical model can be incorporated in the AASHTO Mechanistic Empirical Pavement Design Guide (MEPDG), which will promote the sustainable use of RAP with geocell for roadway construction

Unusual Presentation of the Intracranial Arachnoid Cysts Posing with Treatment Dilemma: A Case Series

A case series comprising of 3 patients with intracranial arachnoid cysts presented with atypical features raising the doubt on the symptomatic nature of the cyst. It posed dilemma on the further management of these patients. In two patients, surgical intervention to decompress the arachnoid cyst was performed which drastically improved the patient’s symptoms. One patient with intracranial arachnoid cyst who has been conservatively managed persists to have symptoms

Efficient neocentromere formation is suppressed by gene conversion to maintain centromere function at native physical chromosomal loci in Candida albicans

CENPA/Cse4 assembles centromeric chromatin on diverse DNA. CENPA chromatin is epigenetically propagated on unique and different centromere DNA sequences in a pathogenic yeast Candida albicans. Formation of neocentromeres on DNA, nonhomologous to native centromeres, indicates a role of non-DNA sequence determinants in CENPA deposition. Neocentromeres have been shown to form at multiple loci in C. albicans when a native centromere was deleted. However, the process of site selection for CENPA deposition on native or neocentromeres in the absence of defined DNA sequences remains elusive. By systematic deletion of CENPA chromatin-containing regions of variable length of different chromosomes, followed by mapping of neocentromere loci in C. albicans and its related species Candida dubliniensis, which share similar centromere properties, we demonstrate that the chromosomal location is an evolutionarily conserved primary determinant of CENPA deposition. Neocentromeres on the altered chromosome are always formed close to the site which was once occupied by the native centromere. Interestingly, repositioning of CENPA chromatin from the neocentromere to the native centromere occurs by gene conversion in C. albicans

OsIAA1, an Aux/IAA cDNA from rice, and changes in its expression as influenced by auxin and light

The Aux/IAA class of genes are rapidly induced by exogenous auxins and have been characterized extensively from many dicot species like Arabidopsis, Glycine max and Pisum sativum. We report here the isolation and characterization of rice (Oryza sativa L. subsp. Indica) OsIAA1 cDNA as a monocot member of the Aux/IAA gene family. The predicted amino acid sequence of OsIAA1 corresponds to a protein of ca. 26 kDa, which harbors all four characteristic domains known to be conserved in Aux/IAA proteins. The conservation of these Aux/IAA genes indicates that auxins have essentially a similar mode of action in monocots and dicots. Northern blot analysis revealed that the OsIAA1 transcript levels decrease in the excised coleoptile segments on auxin starvation, and the level is restored when auxin is supplemented; the increase in OsIAA1 transcript level was apparent within 15 to 30 min of auxin application. Auxin-induced OsIAA1 expression appears to be correlated with the elongation of excised coleoptile segments. In light-grown rice seedlings, OsIAA1 is preferentially expressed in roots and basal segment of the seedling, whereas in the etiolated rice seedlings, the OsIAA1 transcripts are most abundant in the coleoptile. A comparative analysis in light- and dark-grown seedling tissues indicates that the OsIAA1 transcript levels decrease on illumination

Structure and expression analysis of early auxin-responsive Aux/IAA gene family in rice (Oryza sativa)

Auxin exerts pleiotropic effects on plant growth and development by regulating the expression of early auxin-responsive genes of auxin/indoleacetic acid (Aux/IAA), small auxin-up RNA, and GH3 classes. These genes have been studied extensively in dicots like soybean and Arabidopsis. We had earlier characterized a cDNA of the first monocot member of Aux/IAA family from rice. The achievement of the large scale rice genome sequencing combined with the availability of full-length cDNA sequences from Knowledge-based Oryza Molecular Biological Encyclopedia provided us the opportunity to draw up the first comprehensive list of Aux/IAA genes in a monocot. By screening the available databases, we have identified 31 Aux/IAA genes having high sequence identity within the conserved domains I, II, III, and IV. The genomic organization as well as chromosomal location of all the Oryza sativa indoleacetic acid (OsIAA) genes is reported. The rice Aux/IAA proteins can be classified in two groups (A and B) on the basis of their phylogenetic relationship with Arabidopsis Aux/IAA proteins. An evolutionary pattern of the rice Aux/IAA genes has been discussed by analyzing their structure (exon/intron organization) and duplications. Interestingly, the duplication of rice Aux/IAA genes was found to be associated with chromosomal block duplication events in rice. The in-silico analysis has been complemented with real-time polymerase chain reaction analysis to quantify transcript levels of all Aux/IAA family members. OsIAA genes showed differential and overlapping organ-specific expression patterns in light- and dark-grown seedlings/plants. Although auxin enhanced the transcript abundance of most of the OsIAA genes, the effect was more pronounced on OsIAA9, 14, 19, 20, 24, and 31. These results provide a foundation for future studies on elucidating the precise role of rice Aux/IAA genes in early steps of auxin signal transduction

Studies on H2-Assisted Liquefied Petroleum Gas Reduction of NO over Ag/Al2O3 Catalyst

Hydrocarbon-Selective catalytic reduction (HC-SCR) is one of the potential methods to remove NOx emissions from diesel engine, lean burn petrol engines and natural gas engines exhaust. Ag/Al2O3 is a good catalyst for HC-SCR of NOx under lean-burn conditions. Further, addition of small amount of H2 is effective for enhancing HC-SCR activity. This effect is unique to silver and to specific Ag/support combinations, namely, Ag/γ-Al2O3. Various HC reductants, such as: octane, decane, dodecane and propane, have been reported in the literatures. Only a single study on LPG as a reductant over Cu-ZSM catalyst was reported. There was no work reported on H2 assisted LPG over Ag/Al2O3 catalyst. Thus, this gap in the literature is filled with the present investigation of NO reduction over 2 wt.% Ag/Al2O3 catalyst using LPG reductant. The fresh and used catalyst was characterized by various techniques like low temperature N2-adsorption, XRD, XPS and SEM. There was practically no change in the characteristics of the fresh and used catalyst. Two different reductants of CO and LPG were compared for SCR of NO over the catalyst without and with H2-assisted. The experiments were performed in a fixed bed tubular flow reactor under the following conditions: 100mg catalyst; 0.13% NO, 2.5% LPG/CO, 1% H2, 10% O2, rest Ar; total flow rate 60 mL/min; temperature ambient 400 oC and pressure 1 atm. Around 100% conversion of NO was achieved using LPG reductant. Light off temperature of NO reduction significantly reduced by H2assisted LPG reductant. The maximum conversion of NO with CO was limited to 35.15% at temperature of 224 oC and above. Whereas, 97.79 % NO conversion was achieved at 365 oC with LPG reductant. While, the maximum conversions with H2-LPG and H2-CO reductants were 100 and 99.46% at 117 and 220 oC, respectively. Therefore, H2-LPG-SCR of NOx over 2 wt.% Ag/Al2O3 catalyst system can be used to get 100% reduction at low temperature.