A Boussinesq-type Model for Waves Generated by Flow over a Bump

Abstract A uniform flow disturbed by a bump is studied. The effect of the disturbance is presented at the surface, generating wave. The wave propagation is modeled into a couple of equations, in terms of the surface elevation and the depth average velocity. The numerical solution of the equations is simulated to observe the propagation, especially for long run time, using a predictor-corrector method. A steady solitary surface profile is obtained for supercritical upstream flow, similarly for subcritical flow but for negative amplitude. In the transient process, more waves are generated but some of them propagates to the left or right, and only one wave remains above the bump. Mathematics Subject Classification: 35C20, 76B07, 76B2

Hydrological behavior of Alfisols and Vertisols in the semi-arid zone: Implications for soil and water management

Understanding of the hydrological behavior of soils is a prerequisite for developing appropriate soil and water management practices. Such information for Alfisols and Vertisols, the two major soils in the semi-arid tropics (SATs), is scanty especially from a long-term perspective. In this paper, we describe and discuss results from long-term (from 1976 to 2010) hydrological studies conducted on small agricultural watersheds on Vertisols and Alfisols at the ICRISAT Center, Patancheru, India. The hydrological behavior of soils are characterized in terms of runoff volume, peak runoff rate, number of runoff events, soil loss, sediment concentration and deep drainage loss under different rainfall, crop cover and soil moisture conditions to aid in developing effective soil and water management practices. We also provide details on the effects of annual and monthly rainfall on the hydrological behavior of these soils in different rainfall regions. The results show that Alfisols and Vertisols in the SATs have very contrasting hydrological behavior. Several findings emerging from our studies, are rather unexpected. For example, the sandy Alfisols with higher saturated hydrological conductivity generated higher runoff compared to the clayey Vertisols with extremely low saturated hydraulic conductivity. The undesirable early season runoff from Alfisols is higher than from Vertisols. The contribution of 1–2 big storms to annual runoff and soil loss was high on both soils. The contrasting hydrological behavior of these two soils is due to differences in soil characteristics such as crusting, sealing and low structural stability in Alfisols; and the presence of cracks during the early season and formation of micro-cracks during rainless periods in Vertisols. The results suggest that the information from the long-term hydrological studies is useful for determining appropriate soil and water management practices and strategies in different rainfall regions

Duplication 16p11.2 in a child with infantile seizure disorder

Submicroscopic recurrent 16p11.2 rearrangements are associated with several neurodevelopmental disorders, including autism, mental retardation, and schizophrenia. The common 16p11.2 region includes 24 known genes, of which 22 are expressed in the developing human fetal nervous system. As yet, the mechanisms leading to neurodevelopmental abnormalities and the broader phenotypes associated with deletion or duplication of 16p11.2 have not been clarified. Here we report a child with spastic quadriparesis, refractory infantile seizures, severe global developmental delay, hypotonia, and microcephaly, and a de novo 598 kb 16p11.2 microduplication. Family history is negative for any of these features in parents and immediate family members. Sequencing analyses showed no mutations in DOC2A , QPRT , and SEZ6L2 , genes within the duplicated 16p11.2 region that have been implicated in neuronal function and/or seizure related phenotypes. The child's clinical course is consistent with a rare seizure disorder called malignant migrating partial seizure disorder of infancy, raising the possibility that duplication or disruption of genes in the 16p11.2 interval may contribute to this severe disorder. © 2010 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75769/1/33415_ftp.pd

Opportunities for water harvesting and supplemental irrigation for improving rainfed agriculture in semi-arid areas

This chapter discusses the research results and experiences gained in runoff harvesting and supplemental irrigation in the semiarid tropical (SAT) regions of India and Africa. Topics covered include: traditional tank irrigation in SAT India; assessment of adequate water availability in tanks at critical crop growth stages; optimum tank size and other design parameters; efficient application of supplemental irrigation water; crop responses to supplemental irrigation; economic evaluation of runoff storage structures and supplemental irrigation; and watershed-based water harvesting, groundwater recharging and efficient water utilization

Low-Cost Groundwater Recharge through Open Wells in Indian Semi-Arid Tropical watersheds

The traditional runoff harvesting facilities in Indian semi arid tropics (SAT) have degenerated due to lack of proper management and policy support. Due to vagaries of monsoon and scarcity of surface water in Indian SAT, dependence on groundwater has increased tremendously and water resource has transformed from community resource to a private resource. Farmers have dug open wells to draw groundwater from shallow aquifers. With advent of bore well technology and subsidized power, there has been shift in groundwater extraction from shallow aquifers to deeper aquifers creating mining effect. Intensity of rainfall in Indian SAT is grossly adequate to adequately charge the aquifers. A study was made in a watershed at Kothapally, Rangareddy district, AP, to recharge groundwater thru diversion of clean rain runoff in 35 failed (dry) open wells. Quantity of groundwater recharged thru diversion of t~e nlnoff was estimated which averaged 96100 m3 over two yearof study. To store same quantity of runoff on land suiface, it would have required approximately 4 ha land area, Rs 20 lakhs as construction cost and Rs 20,000 as annual maintenance cost. The enhanced water availability in open wells resulted into increased irrigated area in rabi and post rabi seasons. It resulted into increased area under fodder cultivation, milch animals, marketable milk production, area under flowers and vegetables. Area under irrigation and yield increase of annual crops was affected. Increased water availability culminated into increased income and livelihood opportunities for farmers in the watershed

Evaluating Climate Change Mitigation and Adaptation Potential of Conservation Agriculture in Semi-arid Tropics of Southern India

Aims: As climate change related rainfall and temperature variability is being increasingly experienced in the SAT regions, we assessed climate change mitigation and adaptation potential of Conservation Agriculture (CA) by studying effects of minimum tillage (MT) and residue management practices on rain water use efficiency (RWUE), soil moisture, runoff, energy use and carbon dioxide emission in two maize-legume cropping systems. Study Design: The experiment was laid out in split-split plot design with four replications. Place and Duration of Study: The study was conducted at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) farm, Patancheru, Telangana, India during 2010-11 and 2011-12. Methodology: RWUE was calculated as maize equivalent yield divided by rainfall received during the crop season. Integrated digital runoff and soil loss monitoring unit (IDRSMU) was used to measure runoff. Soil moisture content was measured using the gravimetric method (0-30 cm depth) and neutron probe (60-90 cm depth). The soil organic carbon was analyzed following the Walkley-Black method [1]. The diesel consumption in MT and conventional tillage (CT) was estimated following Downs and Hansen (http://www.ext.colostate.edu/pubs) and emission of CO2 was estimated according to EPA, 2009 [2]. Results: Tillage and residue management practices did not show significant effect on RWUE except; CT having significantly higher RWUE over MT during 2011-12. Effect of cropping systems on RWUE was significant but variable during the two years of study. MT-RT (minimum tillage- residue retained) reduced total seasonal runoff by 28.62% and 80.22% compared to CT-RR (conventional tillage- residue removed) in 2010-11 and 2011-12, respectively. Similarly, MT-RT reduced rainwater loss and peak rate of runoff compared to CT-RR in both the years of study. During 2010, MT-RT had higher total soil moisture (v/v) in the 0-90 cm soil depth in sole as well as intercropped maize compared to CT-RR, however, during 2011 MT-RT had higher total soil moisture in sole maize only. As compared to CT, even though, MT improved SOC in 0-15 cm depth but lowered slightly in 15-30 cm depth. RT (residue retained) improved SOC in 0-15 and 15-30 cm depths compared to residue removal (RR). MT-RT had higher or equal SOC in 0-15 and 15-30 cm soil depths compared to CT-RR in both the maize-legume cropping systems. MT saved energy corresponding to 41.49 l of diesel per hectare annually compared to CT. Similarly, MT emitted 110.79 kg less CO2 annually on per hectare basis compared to CT due to reduced diesel use. Conclusion: CA, when adopted by following good agricultural practices and refined to suit the local conditions, could emerge as sustainable production system for climate change mitigation and adaptation of dryland cropping systems in semi-arid tropics of southern India

Climate Change Mitigation and Adaptation Potential of Conservation Agriculture: Effects on Rainwater Use Efficiency, Runoff, Soil Moisture, Soil Organic Carbon and Energy Use

As climate change will likely have adverse effects on agricultural productivity and food security in much of the semi-arid tropics ((SAT, IPCC, 2007), there is need to develop and disseminate production technologies that provide a layer of resilience against such climate change effects on food security. A long-term experiment was initiated at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) farm in Patancheru, India in 2009 rainy season to assess the potential of conservation agriculture (CA) as an alternative and resilient production technology for sustainable crop intensification under rainfed situations in the SAT of southern India. Two tillage treatments -- , normal tillage (NT) minimum tillage (MT), and residue management practices -- residue removal (RR) and residue retention (RT) were tested in maize-chickpea sequence and maize/pigeonpea intercropping systems with four replications. The soil of experimental field was Vertic Inceptisol, which according to USDA is classified as a member of the fine, montmorillonite, isohyperthermic family of paralithic Vertic Ustopepts (Vertic cambisol as per FAO classification); slightly alkaline (pH 7.91) with EC 0.22, medium in organic C (0.42 %) and available P (10.61 kgha-1). Here we present effects of tillage and residue management practices on rainwater use efficiency (RWUE), runoff, soil moisture content and soil organic carbon (SOC) during 2010-11 and 2011-12 seasons. Data from integrated digital runoff and soil loss monitoring unit (IDRSMU, Pathak et al., 2011) were analyzed to estimate runoff in different treatment plots in maize-chickpea system. Soil moisture content was measured using the neutron probe (Troxler model 4302) calibrated under same soil