High-Resolution Quasi-3D Electric Resistivity Tomography for Deciphering Groundwater Potential Zones in Lateritic Terrain

Natural Resources Research - Groundwater is under constant threat of exploitation with increasing demands. Therefore, there is a need for more advanced methods for exploring potential groundwater...     

Airborne LiDAR and Terrestrial Laser Scanning Derived Vegetation Obstruction Factors for Visibility Models

Research presented here explores the feasibility of leveraging vegetation data derived from airborne light detection and ranging (LiDAR) and terrestrial laser scanning (TLS) for visibility modeling. Using LiDAR and TLS datasets of a lodgepole pine (Pinus contorta) dominant ecosystem, tree canopy and trunk obstructions were isolated relevant to a discrete visibility beam in a short‐range line‐of‐sight model. Cumulative obstruction factors from vegetation were compared with reference visibility values from digital photographs along sightline paths. LiDAR‐derived tree factors were augmented with single‐scan TLS data for obstruction prediction. Good correlation between datasets was found up to 10 m from the terrestrial scanner, but fine scale visibility modeling was problematic at longer distances. Analysis of correlation and regression results reveal the influence of obstruction shadowing inherent to discrete LiDAR and TLS, potentially limiting the feasibility of modeling visibility over large areas with similar technology. However, the results support the potential for TLS‐derived subcanopy metrics for augmenting large amounts of aerial LiDAR data to significantly improve models of forest structure. Subtle LiDAR processing improvements, including more accurate tree delineation through higher point density aerial data, combined with better vegetation quantification processes for TLS data, will advance the feasibility and accuracy of data integration.     

Phenotypic plasticity in Bacillus cereus strains isolated from various Antarctic habitats

We studied five strains of psychrotolerant Bacillus cereus （B. cereus） isolated from Antarctic snow （BCsn）, ice （BCic）, lake water （BCwt）, sediment （BCsd）, and soil （BCsl） samples in terms of their growth, biochemical properties, and heat shock re- sponses. Analyses of growth kinetics at 4℃ showed that BCsn had the fastest generation time （16.1 h）, whereas BCWT had the slowest （30.8 h）. Strain BCsd formed the largest zone of lipid hydrolysis （18 mm） whereas BCsn formed the smallest zone （3 mm）.Only BCsd produced gelatinase. These physiological differences illustrate adaptations of B. cereus isolates to different niches. Strains BCsl and BCwr were resistant to all 12 of the antibiotics tested. Strains BCsn, BCio, and BCsd were resistant to cell wall synthesis inhibitors （penicillin and ampicillin） and susceptible to protein synthesis inhibitors （tetracycline and streptomycin）. A carbon-substrate utilization assay revealed that BCsn, BCic and BCwr could specifically utilize D-glucose-6-phosphate, salicin, and 2＇-deoxyadenosine, respectively, indicating a degree of metabolic diversity among these Antarctic B. cereus strains. An analy- sis of heat shock proteins （HSPs） produced in response to a 60℃ heat treatment revealed significant variations in the amounts of HSP33 （p = 0.01, df= 4）, HSP44 （p = 0.003, dr= 4）, and HSP60 （p = 0.04, df= 4） among the strains. This emphasizes the impor- tance of HSPs in bacterial taxonomy. These results show that there are considerable adaptive variations among B. cereus strains from extremophilie environments. This could be significant in evaluating the taxonomy and evolution of this species.     

Grain size analysis and depositional pattern of upper Gondwana sediments (Early Cretaceous) of Salbardi area,districts Amravati,Maharashtra and Betul,Madhya Pradesh

A detailed grain-size analysis of twenty-two sandstone samples from the uppermost Gondwana succession of Salbardi area has been carried out to interpret the depositional pattern. The sandstones are mainly medium to coarse grained, moderately sorted, near-symmetrical to fine-skewed and mesokurtic in nature. Inter-relationship of various parameters shows bimodal nature of sediments having dominance of medium sand. Based on the granulometric analysis, a fluvial environment of deposition is interpreted for the succession.     

Use of remote sensing,GIS and C++ for soil erosion assessment in the Shakkar River basin,India

Soil is an essential resource for human livelihoods. Soil erosion is now a global environmental crisis that threatens the natural environment and agriculture. This study aimed to assess the annual rate of soil erosion using distributed information for topography, land use and soil, with a remote sensing (RS) and geographical information system (GIS) approach and comparison of simulated with observed sediment loss. The Shakkar River basin, situated in the Narsinghpur and Chhindwara districts of Madhya Pradesh, India, was selected for this study. The universal soil loss equation (USLE) with RS and GIS was used to predict the spatial distribution of soil erosion occurring in the study area on a grid-cell basis. Thematic maps of rainfall erosivity factor (R), soil erodibility factor (K), topographic factor (LS), crop/cover management factor (C), and conservation/support practice factor (P) were prepared using annual rainfall data, soil map, digital elevation model (DEM) and an executable C++ program, and a satellite image of the study area in the GIS environment. The annual rate of soil erosion was estimated for a 15-year period (1992–2006) and was found to vary between 6.45 and 13.74 t ha^?1 year^?1, with an average annual rate of 9.84 t ha^?1 year^?1. The percentage deviation between simulated and observed values varies between 2.68% and 18.73%, with a coefficient of determination (R²) of 0.874.     

Improved visibility calculations with tree trunk obstruction modeling from aerial LiDAR

Viewshed and line-of-sight are spatial analysis functions used in applications ranging from urban design to archaeology to hydrology. Vegetation data, a difficult variable to effectively emulate in computer models, is typically omitted from visibility calculations or unrealistically simulated. In visibility analyzes performed on a small scale, where calculation distances are a few hundred meters or less, ineffective incorporation of vegetation can lead to significant modeling error. Using an aerial LiDAR (light detection and ranging) data set of a lodgepole pine (Pinus contorta) dominant ecosystem in Idaho, USA, tree obstruction metrics were derived and integrated into a short-range visibility model. A total of 15 visibility plots were set at a micro-scale level, with visibility modeled to a maximum of 50 m from an observation point. Digital photographs of a 1 m² target set at 5 m increments along three sightline paths for each visibility plot were used to establish control visibility values. Trunk obstructions, derived from mean vegetation height LiDAR data and processed through a series of tree structure algorithms, were factored into visibility calculations and compared to reference data. Results indicate the model calculated using trunk obstructions with LiDAR demonstrated a mean error of 8.8% underestimation of target visibility, while alternative methods using mean vegetation height and bare-earth models have an underestimation of 65.7% and overestimation of 31.1%, respectively.     

Trace fossils and their palaeoenvironmental significance in the Lameta Formation of Salbardi and Belkher area, district Amravati, Maharashtra, India

Trace fossils namely, Planolites, Planolites montanus, Thalassinoides and stuff burrows belonging to the Lameta Formation of Central India are reported for the first time from two new localities, i.e., Salbardi and Belkher area. Both the exposures are well represented by the typical marker lithounits as of Jabalpur, Nand-Dongargaon area of central India, i.e., greenish yellow sandstone, clays of various shades, chertified and brecciated limestones, etc. These successions are devoid of megaforal remains, therefore, these biogenic structures play a significant role in the interpretation of palaeoenvironment and palaeoecology during the deposition of the Lameta sediments. The trace fossils assemblage shows that the benthonic community was mainly polychaetes and crustaceans.     

A Prediction of Solar Cycle 24 Using a Modified Precursor Method

Based on cycles 17 – 23, linear correlations are obtained between 12-month moving averages of the number of disturbed days when Ap is greater than or equal to 25, called the Disturbance Index (DI), at thirteen selected times (called variate blocks 1, 2,… , each of six-month duration) during the declining portion of the ongoing sunspot cycle and the maximum amplitude of the following sunspot cycle. In particular, variate block 9, which occurs just prior to subsequent cycle minimum, gives the best correlation (0.94) with a minimum standard error of estimation of ± 13, and hindcasting shows agreement between predicted and observed maximum amplitudes to about 10%. As applied to cycle 24, the modified precursor technique yields maximum amplitude of about 124±23 occurring about 45±4 months after its minimum amplitude occurrence, probably in mid to late 2011.