Geomorphic risk maps for river migration using probabilistic modeling – a framework

Lateral migration of meandering rivers poses erosional risks to human settlements, roads, and infrastructure in alluvial floodplains. While there is a large body of scientific literature on the dominant mechanisms driving river migration, it is still not possible to accurately predict river meander evolution over multiple years. This is in part because we do not fully understand the relative contribution of each mechanism and because deterministic mathematical models are not equipped to account for stochasticity in the system. Besides, uncertainty due to model structure deficits and unknown parameter values remains. For a more reliable assessment of risks, we therefore need probabilistic forecasts. Here, we present a workflow to generate geomorphic risk maps for river migration using probabilistic modeling. We start with a simple geometric model for river migration, where nominal migration rates increase with local and upstream curvature. We then account for model structure deficits using smooth random functions. Probabilistic forecasts for river channel position over time are generated by Monte Carlo runs using a distribution of model parameter values inferred from satellite data. We provide a recipe for parameter inference within the Bayesian framework. We demonstrate that such risk maps are relatively more informative in avoiding false negatives, which can be both detrimental and costly, in the context of assessing erosional hazards due to river migration. Our results show that with longer prediction time horizons, the spatial uncertainty of erosional hazard within the entire channel belt increases – with more geographical area falling within 25 % &lt; probability &lt; 75 %. However, forecasts also become more confident about erosion for regions immediately in the vicinity of the river, especially on its cut-bank side. Probabilistic modeling thus allows us to quantify our degree of confidence – which is spatially and temporally variable – in river migration forecasts. We also note that to increase the reliability of these risk maps, we need to describe the first-order dynamics in our model to a reasonable degree of accuracy, and simple geometric models do not always possess such accuracy.</p

Accounting for variation in rainfall intensity and surface slope in wash-off model calibration and prediction within the Bayesian framework

Exponential wash-off models are the most widely used method to predict sediment wash-off from urban surfaces. In spite of many studies, there is still a lack of knowledge on the effect of external drivers such as rainfall intensity and surface slope on wash-off predictions. In this study, a more physically realistic "structure" is added to the original exponential wash-off model (OEM) by replacing the invariant parameters with functions of rainfall intensity and catchment surface slope, so that the model can better represent catchment and rainfall conditions without the need for lookup tables and interpolation/extrapolation. In the proposed new exponential model (NEM), two such functions are introduced. One function describes the maximum fraction of the initial load that can be washed off by a rainfall event for a given slope and the other function describes the wash-off rate during a rainfall event for a given slope. The parameters of these functions are estimated using data collected from a series of laboratory experiments carried out using an artificial rainfall generator, a 1 m2 bituminous road surface and a continuous wash-off measuring system. These experimental data contain high temporal resolution measurements of wash-off fractions for combinations of five rainfall intensities ranging from 33 to 155 mm/h and three catchment slopes ranging from 2 to 8%. Bayesian inference, which allows the incorporation of prior knowledge, is implemented to estimate parameter values. Explicitly accounting for model bias and measurement errors, a likelihood function representative of the wash-off process is formulated, and the uncertainty in the prediction of the NEM is quantified. The results of this study show: 1) even when the OEM is calibrated for every experimental condition, the NEM's performance, with parameter values defined by functions, is comparable to the OEM. 2) Verification indices for estimates of uncertainty associated with the NEM suggest that the error model used in this study is able to capture the uncertainty well

K-Sign in retrocaecal appendicitis: a case series

which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background: Variations in position of the vermiform appendix considerably changes clinical findings. Retrocaecal appendicitis presents with slightly different clinical features from those of classical appendicitis associated with a normally sited appendix. K-sign looks for the presence of tenderness on posterior abdominal wall in the retrocaecal and paracolic appendicitis. This is the first case report of this kind in the literature. The K-sign has been named, as a mark of respect, after the region of origin of this sign, Kashmir, so called as &quot;Kashmir Sign&quot;. The sign being present in view of inflamed appendix crossing above its non palpable position above iliac crest on the posterior abdominal wall and the tenderness is by irritation of posterior peritoneum Case presentation: The author is reporting a case series of four patients in whom a K-sign, a clinical sign, was elicited and found positive on the posterior abdominal wall for presence of tenderness in a specific area bound by the 12th rib superiorly, spine medially, lateral margin of posterior abdominal wall laterally and iliac crest inferiorly and was found to be present in three retrocaecal and one paracolic appendicitis. Each case had tenderness in this specific area o

Quantification of Nutrients Recycled by Tank Silt and its Impact on Soil and Crop - A Pilot Study in Warangal District of Andhra Pradesh

Tanks were an integral part of rural life in India traditionally. However, with decreasing collective action by the community inappropriate soil and water management practices adopted by the farmers, encroachments of tanks and waterway by the individuals resulted in neglect of the tanks in villages. Good practices such as desilting and application of silt to agricultural fields were abandoned. Continued mining by crops and reduced application of organic manures have resulted in deficiency of several nutrients particularly that of micronutrients. ICRISAT in association with Modern Architects of Rural India (MARI), an NGO conducted a pilot project and quantified major and micro-nutrients present in the tank silt and also its impact on soil health and crop yields. The depth of silt in 12 tanks de-silted ranged from 1.2 m to 3.0 m. The pH of the tank silt ranged from 6.5 to 8.5, while the organic carbon content was found to be low (0.5% to 0.8%). The available N content of tank silt ranged from 328 mg kg-1 to 748 mg kg-1, available P 5 to 35 mg kg-1 and K 271 to 522 mg kg-1 silt. Similarly, available S ranged from 12 mg kg-1 to 30 mg kg-1 zinc from1.2 mg kg-1 to 5.6 mg kg-1 and boron 0.4 to 0.8 mg kg-1 silt. Microbial population was found to be low and it could be due to excessive use of pesticides for cash crops like cotton and chilli grown in the catchment area. Textural analysis indicated 70 to 80% clay, while the silt ranged from 15 to 25%. Addition of tank silt at 50, 100, 150 and 375 tractor loads per hectare improved the available water content by 0.002, 0.007, 0.012 and 0.032 g g-1 of soil, respectively in the plough layer and enhanced the tolerance of rain-fed crops to moisture stress by three to five days. The farmers could recover the investment made on transport of the silt through increased net profit in cotton and chilli compared to turmeric and maize. Further, the saving on pesticides alone was to the tune of Rs. 2500 ha-1 in cotton and chilli crops, which has indirect beneficial impact on the ecosystem. De-silting was found to be an economically viable activity both in terms of farmers’ and project’s perspective to create more storage capacity as well as to return the silt back to the fields. De-silting activity needs greater support from the government and non-governmental agencies for achieving multiple outputs like employment generation for landless, rejuvenating of the tanks and for enhanced productivity of dryland crops

Managing and harnessing soil flora/fauna biodiversity for sustainable crop production in the semi-arid tropics

The Green Revolution initially resulted in high-yielding cereal varieties responsive to increased inputs that addressed the food needs of several countries, particularly those in Asia. However, after three decades, farmers have started experiencing difficulty in maintaining such high yields, even with increasing levels of inputs. Second-generation issues, fall-outs of the Green Revolution, have now surfaced. These issues include problems associated with soil quality, sustainability, and environmental degradation. Prior to the Green Revolution sustenance agriculture was relatively free from such problems, but it operated at a low level of productivity, that could not sustain the food needs of Asia's evergrowing population

Sustainable agriculture in the semi-arid tropics through biological nitrogen fixation in grain legumes

As biological nitrogen fixation (BNF) is dependent upon physical, environmental, nutritional and biological factors, mere inclusion of any N2-fixing plant system does not guarantee increased contributions to the soil N pool. In the semiarid tropics (SAT) where plant stover is also removed to feed animals, most legumes might be expected to deplete soil N. Yet beneficial legume effects in terms of increased yields in succeeding cereal crops have been reported. Such benefits are partly due to N contribution from legumes through BNF and soil N saving effect. In addition, other non-N rotational benefits, for example, improved nutrient availability, improved soil structure, reduced pests and diseases, hormonal effects are also responsible. Research on the contribution of grain legumes in cropping systems and the factors affecting BNF is reviewed. Ways are suggested for exploiting BNF for developing sustainable agriculture in SAT. A holistic approach involving host-plant, bacteria, environment and appropriate management practices including need based inoculation for enhancing BNF in the cropping systems in SAT is suggeste

Deformation of Nanowires and Nanotubes

In this article, we have investigated the consequences of the next to the leading order correction to the effective field theory of nanostructures. This has been done by analyzing the effects of deformed Heisenberg algebra on nanowires and nanotubes. We first deform the Schrodinger equation with cylindrical topology. Then specific solutions to the deformed Schrodinger equation with different boundary conditions are studied. These deformed solutions are used to investigate the consequences of the deformation on the energy of nanowires and nanotubes.Comment: 9 pages, 6 figure

Effect of a High Nodulating Selection of Chickpea Cultlvar ICC 4948 on 5011 Properties of a Chlckpea- Sorghum Cropping System Yield and

Plants of widely different nodulation capacities occurring in a chickpea variety ICC 4948 (=0 130) and lat-er developed into separate lines were compared in ch ickpcap$orghum field. a experiment. The high nodul,'ing (liN) chickpca scl.clion produced only marginally h i g her' grai n yield (3.3·6.9%, mean or the two N levels) than th.'lt of the unselected normal variety and the: low nodulating (LN) sd�ction. Out t h e liN selection fixed signiricanUy more atmospheric nitrogen at low soil N (as measured by acetylene reduction a\.:tivity). and also liupported increased microbial plots activity in the rhizosphcre. Also. at low soil mineral N I.::vel. the microbial (lush C:N ratio in the of the of the liN selection was narrower (16.0) than that in plols LN (24.4) nnd nonnodulating (20.4) selections. (ncreased microbial activity. along with a narrower flush C:N ratio in the case. of HN seh:clions compared with the LN selection, lead to nil increased availability of N for the following sorghum crop. This resulted in an extra uptake of 20 kg N ha·1 by chickpea and! sorghum together. These studies indicated the benefits of liN selections of chickpea under low soil N and inigated conditions for increased N yield and incrensed microbial activity in a chickpea�sorghum cropping syslem These results are for I year only and suggesl tile need 10 s lu dy the cumul.tive crre� . of the high BNF lines on crop productivity over lime in a cropping systems perspective

Growth promotion of maize by phosphate-solubilizing bacteria isolated from composts and macrofauna

Five bacterial strains with phosphate-solubilizing ability and other plant growth promoting traits increased the plant biomass (20–40%) by paper towel method. Glasshouse and field experiments were conducted using two efficient strains Serratia marcescens EB 67 and Pseudomonas sp. CDB 35. Increase in plant biomass (dry weight) was 99% with EB 67 and 94% with CDB 35 under glasshouse conditions. Increase in plant biomass at 48 and 96 days after sowing was 66% and 50% with EB 67 and 51% and 18% with CDB 35 under field conditions. Seed treatment with EB 67 and CDB 35 increased the grain yield of field-grown maize by 85% and 64% compared to the uninoculated control. Population of EB 67 and CDB 35 were traced back from the rhizosphere of maize on buffered rock phosphate (RP) medium and both the strains survived up to 96 days after sowing