A Crop–Weather Model for Prediction of Rice (Oryza sativa L.) Yield Using an Empirical-Statistical Technique

Rice is the staple food in many countries and is grown in varied climates from per‐humid to semiarid areas. Crop–weather models were used to predict rice yield in India. However, in spite of a significant influence of solar radiation on rice yield, none of these models used solar radiation as one of the predictors. In this paper, an attempt was made to predict the first season (June–September) rice yield at Coimbatore, Tamil Nadu, India by including solar radiation as one of the predictors. Ten years (1987/88–1996/97) data were used for the study. Seven predictors viz., percentage of rice area during first season (X₁), number of days with minimum temperature below 22 °C in August and September (X₂), average daily maximum temperature for three months (July, August and September; X₃), average daily minimum temperature for three months (July, August and September; X₄), total of average sunshine hours in August and September (X₅), and total rainfall of July, August and September (X₆) total average solar radiation of August and September (X₇) were selected based on earlier report. Full model and stepwise regression analysis were performed using MSTAT computer package. The full model regression without solar radiation as predictor (Model I) recorded comparatively less R² (0.6292). Inclusion of solar radiation (Model II) enhanced the R² value considerably (R²=0.9464). Seven variables were further subjected to stepwise regression analysis and only four predictors were retained in the final model (Model III) with an R² value of 0.9234. The model III with minimum parameters Y=22119.5758 + 19.6898, X₁ ? 150.9261, X₂ ? 1126.7501, X₄ + 0.7179 X7 can be used to predict the first season rice yield (Y) at Coimbatore, India.     

Imbibition of soybean seeds in warm water results in the release of copious amounts of Bowman-Birk protease inhibitor, a putative anticarcinogenic agent

Protease inhibitors play a protective role against pathogenic microorganisms and herbivorous insects. The two predominant protease inhibitors of soybean seeds are the Kunitz trypsin inhibitor (KTI) and Bowman-Birk protease inhibitor (BBI). In this study, we report that soybean seeds incubated in warm water release large amounts of proteins into the surrounding media. Two-dimensional gel electrophoresis analysis of the seed exudates resulted in the separation of 93 distinct protein spots out of which 90 spots were identified by LC-MS/MS. The basic 7S globulin and the BBI are the two predominant proteins found in the soybean seed exudates. In addition to 7S and 11S seed storage proteins, others known to protect the seeds against pathogens and pests including KTI, peroxidase, α-galactosidase, and endo-1.3-β-glucanase were also identified in the seed exudates. Soybean seed exudate obtained by incubating the seeds in warm water was also able to inhibit the growth of human breast cancer cell line MCF-7. Since soybean seeds release large amounts of enzymatically active BBI when immersed in warm water, our procedure could be exploited as a simplified alternative method for the preparation of BBI concentrate which is being used as a cancer chemoprotective agent.     

Accumulation of Cadmium and Antioxidant and Hormonal Responses in the Indian Major Carp <Emphasis Type="Italic">Cirrhinus mrigala</Emphasis> During Acute and Sublethal Exposure

Acute (24 h) and sublethal (35 days) effects of cadmium chloride (CdCl₂) were examined in Cirrhinus mrigala using various endpoints (accumulation pattern, thyroid hormones (THs), and antioxidants). The mean concentrations of CdCl₂ for 24 and 96 h were found to be 35.974 and 22.387 mg L^?l, respectively. LC50 concentration of CdCl₂ for 24 h (35.97 mg L^?l) was used for the acute study. For the sublethal studies, fish were exposed to 3.59 mg L^?1 (Treatment I) and 7.19 mg L^?1 (Treatment II) corresponding to 1/10th and 1/5th of 24 h LC50 of the CdCl₂. During acute exposure, higher accumulation of CdCl₂ was noticed in the gill, liver, and kidney of C. mrigala, which is found in the order gill > liver > kidney tissues. Similarly, in sublethal treatments (Treatment I and II), a concentration and time-dependent increase of CdCl₂ accumulation was noticed in the order of gill > liver > kidney. GSH, GST, and GPx activities were found to be relatively lower from the treated groups in both acute and sublethal treatments. However, LPO activity was significantly increased in CdCl₂-treated fish C. mrigala. Further, plasma T₃ reduction was more pronounced than T₄ in acute study. During sublethal treatments, both T₄ and T₃ levels showed a continuous decrease as the exposure period extended. All the values in this study were statically significant (P < 0.01 and P < 0.05).     

Influence of Damping on the Bending and Twisting Modes of Flax Fibre-reinforced Polypropylene Composite

The effects of damping on the bending and twisting modes of flax fibre-reinforced polypropylene composites are investigated. The laminate was manufactured by a vacuum bagging process; its dynamic behaviour was then found from the vibration measurements of a beam test specimen using an impulse hammer technique to frequencies of 1 kHz. The frequency response of a sample was measured, and the bending and twisting responses at resonance were used to estimate the natural frequency and loss factor. The single-degree-of-freedom circle-fit method and Newton’s divided differences formula were used to estimate the natural frequencies as well as the loss factors. The damping estimates were also investigated using a “carpet” plot. The results show significant variations in loss factors depending on the type of mode. The loss factor generally lies in the range of 1.7-2.2 % for the bending modes, while 4.8 % on average for the twisting modes. Numerical estimates of the response, and in particular the natural frequencies, were made using a Mechanical APDL (ANSYS parametric design language) finite element model, with the beam being discretised into a number of shell elements. The natural frequencies from the finite element analysis show reasonably good agreement (errors < 5 %) with the measured natural frequencies.     

Effects of mutual shading of tree crowns on prediction of photosynthetic light-use efficiency in a coastal Douglas-fir forest

Gross primary production (GPP) is often expressed as the product of absorbed photosynthetically active radiation and the efficiency (epsilon) with which a plant community uses absorbed radiation in biomass production. Light-use efficiency is affected by environmental stresses, and varies diurnally and seasonally. Uncertainty about epsilon can be a serious limitation when modeling GPP. An important determinant of epsilon is the amount and type of solar radiation incident on a canopy, because an abundance of light can trigger a photo-protective reaction, diminishing GPP. The radiation regime in a forest canopy is determined by the predominant sky conditions and by mutual shading of tree crowns. Shading effects, producing shifts in the amount of incident direct and diffuse solar radiation, have been largely ignored, however, because they depend on forest structure and are difficult to measure. We describe a new approach for estimating changes in mutual canopy shading throughout the day and year based on a canopy structure model derived from light detection and ranging (LiDAR). Proportions of canopy shading were then combined with eddy covariance data to assess the explanatory power for variance in epsilon by regression tree analysis over half-hourly, daily and weekly time scales. The approach explained between 75 and 97% of variance in epsilon, representing an increase of between 5 and 16% compared with models driven solely by meteorological variables.     

Cross impact analysis and data mining variable hierarchy of stakeholder responses for sustainable development of Schizothorax fisheries in Kashmir lakes,India

This study documented the history of lake fisheries in Kashmir, India, and estimated the trends in fish production using Kane's cross impact analysis (CIA) and stakeholders’ willingness to pay (WTP) for the restoration of the Schizothorax fisheries. Kane's CIA model for Lake Dal indicated a perceptible drop in Schizothorax production in the long run, and that the total catch is being maintained by an increasing contribution by carp. In Lake Wular, the CIA indicated that the size of the lake still offers scope for the co‐existence and growth of both Schizothorax as well as carp. A Classification and Regression Tree (CART) model was used to data mine multiple stakeholder responses to make a case for sustainable development of the Schizothorax fisheries in the lakes of Kashmir. The amount of time spent on the lakes to earn their livelihoods emerged as the single most important variable that determined WTP by stakeholders followed by income, type of stakeholder and age. The pruned tree gave the hierarchy of the variables that determined WTP. The results made a strong case for a concerted multi‐institutional action plan for the restoration of the Schizothorax fisheries in the lakes of Kashmir.