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Key soil parameters, organic matter, soil pH and plant nutrients determine the capacity of a soil to sustain plant and animal productivity. Conservation agriculture (CA) and crop diversification or intensification may change these soil parameters positively or negatively, which eventually affect long-term sustainability. We monitored these key soil properties (at depths of 0-15 and 15-30 cm) under CA-based sustainable intensification practices: zero-till (ZT), and crop residue retention, and crop rotations on Inceptisols and Entisols in the Eastern Ganga Alluvial Plains from 2014 to 2017. The rainfall of this sub-tropical region is 1273-3201 mm. Soil organic carbon (C) ranged within 0.46-1.13% and generally followed (positive) rainfall gradients. At all sites, the soil under ZT tended to have higher organic C than conventional tillage (CT). Soil pHH2o ranged within 5.7-7.8 across the region. At all sites, soil pH generally decreased under ZT compared to CT. This was most marked at some acidic soil sites where pH decreased by up to 0.4 units; the lower the initial soil pH, the higher was the decrease in pH under ZT practice. In contrast, the reverse trend was observed for soil organic C. Partial nutrient balances for N, P and K in rice-wheat and rice-maize systems were positive for N and P ( Additional keywords: cropping systems, maize, partial nutrient balance, rice, soil organic C, soil pH, South Asia, wheat. Received 14 June 2019, accepted 30 July 2019, published online 10 September 2019, Introduction Conservation agriculture (CA) and crop diversification or intensification are the major components of the emerging farming systems for ensuring food security in South Asia (Jat et al. 2014; Islam [...]

Nearly a century ago it was recognized (1) that radiation absorption by stellar matter controls the internal temperature profiles within stars. Laboratory opacity measurements, however, have never been performed at stellar interior conditions, introducing uncertainties in stellar models (2-5). A particular problem arose (2,3,6,8) when refined photosphere spectral analysis (9,10) led to reductions of 30-50 per cent in the inferred amounts of carbon, nitrogen and oxygen in the Sun. Standard solar models (11) using the revised element abundances disagree with helioseismic observations that determine the internal solar structure using acoustic oscillations. This could be resolved if the true mean opacity for the solar interior matter were roughly 15 per cent higher than predicted (2,3,6-8), because increased opacity compensates for the decreased element abundances. Iron accounts for a quarter of the total opacity (2,12) at the solar radiation/convection zone boundary. Here we report measurements of wavelength-resolved iron opacity at electron temperatures of 1.9-2.3 million kelvin and electron densities of (0.7-4.0) X [10.sup.22] per cubic centimetre, conditions very similar to those in the solar region that affects the discrepancy the most: the radiation/convection zone boundary. The measured wavelength-dependent opacity is 30-400 per cent higher than predicted. This represents roughly half the change in the mean opacity needed to resolve the solar discrepancy' even though iron is only one of many elements that contribute to opacity., In the region of the solar radiation/convection zone boundary (11), the electron temperature [T.sub.e] ≅ 2.1 X [10.sup.6] K, the electron density [n.sub.e] ≅ 9 X [10.sup.22] [cm.sup.-3], and the [...]

A study was undertaken to investigate the rate of dissolution of the various Phosphorus (P) sources in an alluvial soil of Bihar under an incubation experiment in the laboratory for 35 days with 5 treatments viz., Control; RP (Rock Phosphate) @ 100% of the RDP (Recommended Dose of Phosphorus); 100% of RDF (Recommended Dose of Fertilizer NPK); REC (Rock phosphate Enriched Compost) @ 100% of the RDP and 50% RDP+REC @ 50% of the RDP. The P release pattern was determined for every treatment at a sampling interval of 7 days. The integrated treatment involving REC and P-fertilizer (50:50) performed better than other treatments. This combination released greater labile P (16.14 mgkg−1), Fe-Al-bound P (74.48 mgkg−1), and Ca bound P (147.04 mgkg−1) in soil. It could be concluded that enriched compost (50%) along with the reduced application (50%) of inorganic P fertilizer could be very helpful in supplementing the P requirement of plants by increasing its release and availability under naturally P deficient conditions. [ABSTRACT FROM AUTHOR]

Spar Wingskin Joint (SWJ) comprises of a thin spar which overlaps and is co-cured to a thick wingskin by suitable adhesive materials. These joints are mostly used in integral modular fabrication of aircraft and fuselage wing structures usually made with curved laminated Fibre Reinforced Polymeric (FRP) composite panels. This paper deals with the analyses of initiation of adhesion failure and its propagation in SWJs subjected to transverse loadings using Finite Element Analyses (FEA) and fracture mechanics approach. Normal and shear stress distributions at different interfacial locations between the adherends and the adhesive have been evaluated. Tsai-Wu coupled stress failure criteria have been used to identify the location of onset of adhesion failure. The critical location for onset of adhesion failure has been found to be at the toe-end of the spar wingskin overlap region. Pre-embedded adhesion failure has been simulated at this location and Strain Energy Release Rate (SERR) components corresponding to Mode I, Mode II and Mode III of adhesion failure have been determined using the principle of Virtual Crack Closure Technique (VCCT). Rate of propagation of adhesion failure has been evaluated by sequential release of Multi-Point Constraint (MPC) and contact finite elements provided at the pre-embedded failure front. It has been observed that Mode I component of SERR primarily governs the process of adhesion failure propagation. The appropriate spar overlap length on the wingskin has been determined in order to prevent adhesion failure. Further, an attempt has been made to improve the structural integrity of the SWJ by reducing the stress concentration at the ends of spar and wingskin overlap. This has been achieved by obtaining a favourable stress distribution over the entire joint structure by using Functionally Graded Materials (FGM) in the spar and wingskin adherend instead of FRP composite panels. Exponential gradation indices have been used for material grading of the spar and wingskin adherends. It has been seen that peel and shear stresses and values of SERR components as well as total SERR reduce significantly by use of FGMs with suitable exponential material grading index. [ABSTRACT FROM AUTHOR]

3D Finite Element Analyses have been carried out for Spar Wingskin Joints made with laminated Graphite Fibre Reinforced Plastic composites subjected to uniformly distributed transverse load. The delamination has been pre-embedded at the most likely location, i.e. in resin layer between the top and next ply of the fibre reinforced plastic laminated wingskin and near the spar overlap end. Multi-Point Constraint finite elements have been made use of at the vicinity of the delamination fronts. This helps in simulating the growth of the embedded delamination at both ends. The inter-laminar peel and shear stresses responsible for causing delamination damage have been evaluated. Strain energy release rate components corresponding to the Mode I (opening), Mode II (sliding) and Mode III (tearing) of delamination are determined using the principle of Virtual Crack Closure Technique. These are seen to be different and non-self-similar at the two fronts of the embedded delamination. Mode I Strain energy release rate ( G I ) primarily governs the process of delamination propagation. [ABSTRACT FROM AUTHOR]

Adhesive bonding techniques have increased its application in automobile industries. The most common bonded joint configuration is the lap-shear joint, which when subjected to loading shows a differential substrate straining at the overlap ends. One of the methods to improve its performance is by introducing a reverse bent angle to the adherends at the overlap area. In this paper, the parameters which affect the strength of the reverse bend joints are found out by conducting experiments on different specimens. A detailed study was carried out showing the trends in the joint performance by varying the input parameters. Preformed angle at the overlap area, overlap length, ultimate tensile strength and modulus of the substrates have shown significant effect on the improvement of strength. For most of the adherends used in the automotive industries it has been found that a 10 degree preformed reverse bend joint consistently showed a 15 percent improvement in the strength compared to the traditional lap-shear joint. A model was developed based on Artificial Neural Networking system identification methods to predict the optimum joint configuration based on the given input parameters. This can be used to design high-performance adhesive bonded joints for parts and assemblies in automotive and aerospace industries. [ABSTRACT FROM AUTHOR]

Toxoplasmosis is a worldwide zoonosis. The ingestion of uncooked/undercooked meat and consumption of water contaminated with Toxoplasma gondii oocysts excreted by felids are the main modes of transmission of this parasite. T. gondii has been reported in multiple cervid species; however, little is known of the parasite in North American elk ( Cervus canadensis ). In the present study, antibodies to T. gondii were detected in serum of wild elk from Pennsylvania collected during 2013–2016 by the modified agglutination test (MAT, cut-off 1:25); 221 of 317 (69.7%) had MAT titers of 1:25 in 19, 1:50 in 28, 1:100 in 34, and 1:200 or higher in 140. Thus most (44.1%) elk had relatively high titers. Seroprevalence was slightly higher in males (76.9%) than females (67.5%, not statistically significant, Chi-square tests, P < 0.0001) and was higher in adults (76.5%) than yearlings (46.4%, Odds ratio 3.82; 95% CL 1.72–8.47; P = 0.001) or calves (21.7%, Odds ratio 12.58; 95% CL 4.51–35.10; P < 0.0001). Annual seroprevalence was relatively stable throughout the period tested and ranged from 66.6% to 72.2%. Of the 101 elk harvested in 2016, hearts were bioassayed from 20 elk and tongues were bioassayed from 56; all tongue samples were negative. Viable T. gondii was isolated from hearts of two female elk, one of these was a seronegative adult and the other was a calf with no serum available for testing. Both T. gondii isolates were cultivated in cell culture and DNA derived from tachyzoites was characterized using the PCR-RFLP markers including SAG1, SAG2 (5′- 3′SAG2 and altSAG2), SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico. One isolate belongs to ToxoDB PCR-RFLP genotype #2 and the other is genotype #5. Both genotypes are frequently identified in animals in North America. [ABSTRACT FROM AUTHOR]

• Tissue cyst formation in pork of 8 pigs was studied by mouse bioassay 7 and 14 days after infection with Toxoplasma gondii. • Bioassay of 5, 10, 50 g samples of meat revealed uneven distribution of tissue cysts. Among the meat sources of Toxoplasma gondii , pork is considered important in the epidemiology of toxoplasmosis in the USA. How soon after infection T. gondii forms tissue cysts in pork is unknown. In the present study, eight serologically negative ˜ 3 months old pigs were fed mouse tissues infected with VEG (Type III) strain of T. gondii and euthanized 7 (4 pigs) and 14 days (4 pigs) post-inoculation (p.i.). Meat from the right shoulder of each pig was bioassayed in mice for T. gondii tissue cysts by peptic digestion. From each pig, the shoulder muscle was cut at random spots into 5 g, 10 g and 50 g portions. Extreme care was taken to use different scalpels and forceps to minimize cross contamination among 17 samples (6 replicates of each 5 g and 10 g portions and 5 replicates of 50 g). From the four pigs euthanized at 7 days p.i., a composite of ˜ 200 g of leftover meat from each shoulder was bioassayed in cats and their feces were tested for oocyst excretion. All eight pigs developed T. gondii antibodies (modified agglutination test, MAT, 1: 80 or higher) and viable T. gondii was isolated from shoulder meat of each pig. All four cats fed pork from excreted T. gondii oocysts. The density of T. gondii , based on mouse infectivity, varied within 5–50 g samples each pig, and between pigs within the same group, day 7 versus day 14 p.i. There were no significant differences in mouse bioassay results obtained with day 7 versus day 14 infected pigs. Overall, the rate of isolation of T. gondii increased with sample size of meat bioassayed. Results demonstrate that tissue cysts are formed early in infection and they are unevenly distributed. [ABSTRACT FROM AUTHOR]