Latent heat flux estimation in clear sky days over Indian agroecosystems using noontime satellite remote sensing data

A simplified evaporative fraction (Λ) based single-source energy balance scheme was tested with moderate resolution (1 km) noontime satellite observations to evaluate clear sky latent heat flux (λE) estimates over diverse agricultural landscapes. This approach uses two-dimensional (2D) scatter between land surface temperature (LST) and albedo to determine Λ. The operational utility of this scheme was demonstrated for estimating regional evapotranspiration and consumptive water use during rabi (November to April) crop growing season to predict pre-harvest wheat yield (error within 15.9% of reported mean) using time series data. The existence of triangular relations between Λ and LAI (leaf area index) or NDVI (normalized difference vegetation index) was found with basal line (hypotenuse) linearly coupled with LAI or NDVI at low level of surface soil wetness. The analysis of diurnal course of in situ Λ proved the validity of constant-Λ hypothesis over pure, uniform, homogeneous crop canopies but showed irregular and wave-like patterns over heterogeneous, mixed crop canopies. The root mean square error (RMSE) of noontime and daytime average λE estimates with respect to in situ λE measurements were also smaller over homogeneous agricultural canopies (41 and 23 W m⁻²) with correlation coefficients (r) 0.94 and 0.96, respectively, from 135 clear sky datasets as compared to RMSE over heterogeneous ones (59 and 28 W m⁻² with r = 0.66 and 0.82, respectively from 22 datasets). The intercomparison with another Λ based approach (LST–NDVI 2D scatter) showed the supremacy of Λ determined from LST–albedo 2D scatter. The efficiency of LST–NDVI scatter was better during the dry down or water limited phases of crop growth only. The uncertainties of λE estimates were attributed to errors in core radiation budget inputs, relative loss of conservativeness of Λ due to canopy heterogeneity, and the inherent limitations of the single-source approach. There is further scope to reduce present λE uncertainties by combining the new findings on Λ (LST–albedo scatter)–NDVI triangular relations, diurnal Λ and two-source radiation budget.     

Inorganic pyrophosphatase activity in water stressed excised rice leaves

Summary Changes in the inorganic pyrophosphatase (EC 3.6.1.1) activity and the chlorophyll and -amino nitrogen levels were studied in excised leaves of rice (Oryza sativa L. cv. Ratna) subjected to various degrees of water stress. Chlorophyll level decreased and a-amino nitrogen level increased in the turgid leaves floating on water; these changes were accelerated when the leaves were subjected to water stress (Figs. 2, 3). The decrease with time in the activity of alkaline inorganic pyrophosphatase and the increase with time in the activity of acid inorganic pyrophosphatase in water-floated turgid leaves were accelerated following water stress (Figs. 4, 5). There was an accelerated decline in the ratios of alkaline to acid inorganic pyrophosphatase activity in stressed compared to turgid leaves (Fig. 6). It was concluded that water stress enhances the senescence of excised rice leaves and that the changes in the activities of alkaline and acid inorganic pyrophosphatases can be taken as indicators of water stress in rice leaves.Work supported by grant from the Extra Mural Research Unit, Council of Scientific and Industrial Research, New Delhi to Dr. D. Mishra. Mr. S. Dwivedi is a University Grants Commission Junior Research Fellow     

Chloroform Associated Health Risk Assessment Using Bootstrapping: A Case Study for Limited Drinking Water Samples

Chlorine is the most commonly used disinfectant for watertreatment but when in contact with organic precursors it producestoxic compounds known as trihalomethanes (THMs). Chloroform isthe most commonly occurring THM and constitutes approximately90% of the THM concentration. A study was conducted inNewfoundland for estimating the chloroform content in thedrinking water supplies in Clarenville and St. John's. Thesampling program was conducted in two stages, July and October-November. Higher concentrations of chloroform were observed in Clarenville but in St. John's the concentrations werewithin Health Canada guidelines. The chloroform is a probablehuman carcinogen and is categorised as `B2' by U.S. EnvironmentalProtection Agency (U.S. EPA). The human health risk associatedwith consumption of drinking water was estimated by performingprobabilistic analysis. In the first phase bootstrap simulations(B = 250) were performed to calculate the variability in thedata. The normal distribution was found the best-fitted distribution to chloroform concentration data. For eachbootstrapped run 1000 Monte Carlo Simulations (MCS) wereperformed in the second phase. The cancer risk was estimatedusing dose-response relationship of chloroform. Appropriateprobability density functions (PDFs) were defined subjectivelyfor intake rate, body weight, exposure duration, exposurefrequency and averaging time. The excess lifetime human cancerrisk varied from 0.5 × 10^-4 to 4.0 × 10^-4, and zero to 1.0 × 10^-4 for Clarenvilleand St. John's, respectively. The average cancer risks in Clarenville and St. John's communities were 1.2 × 10^-4 and 2.5 × 10^-5. The estimated probabilitiesof exceedences above 100 ppb (μg L^-1), were 100 and 2.5% for Clarenville and St. John's, respectively which emphasised the need for water treatment. Granular Activated Carbon (GAC) was proposed as one of the potential treatment technology for risk reduction in St. John's community. The treatment efficiency of a proposed technology was assumed uniformly distributed and revised risks were calculated. Theaverage risk in St. John's can be reduced to 8.0 ×10^-6 after treatment.     

Photosynthetic Response of Wheat to Soil Water Deficits in the Tropics

The changes in photosynthetic rate and translocation of photosynthates in winter wheat (Triticum Aestivum L.) grown in lysimeters were studied, in response to periodic soil water deficit during late tillering and flowering stages. Soil water deficits were imposed to previously nonstressed plants during late tillering and flowering states. Timing of irrigation was scheduled according to the ratio between irrigation water applied and cumulative pan evaporation (IW/CPE) of 0.75 (low deficit), and 0.5 (moderate deficit), as well as by suspending irrigations after crown root initiation stage (severe deficit). To determine the rate of photosynthesis, a short radioactive pulse of ¹⁴CO₂ with 300 ppm concentration was given to second leaf from the top at tillering, and to the flag leaf at flowering stages for 20 second exposure time. The translocation of photosynthates was estimated by scanning ¹⁴C activity in different plant parts. In late tillering the midday Photosynthetic rate (PR) was significantly 3 mg CO₂ dm^?2 h^?1 lower under low water deficit (WD₁) than under zero water deficit (WD₀). Under higher stress conditions, soil water acted as a limiting factor to keep the rate from rising above 13.2 during stress at late tillering (WD₂), 14.5 flowering (WD₄), and 10.0 mg CO₂ dm^?2 h^?1 for stress at both the growth stages (WD₅), respectively. The difference in daily accumulated photosynthesis (8 h), between stressed and nonstressed were 15, 40, 42, and 77 mg CO₂ dm^?2 h^?1 respectively at WD₁ WD₂, WD₄, and WD₅. The retention of ¹⁴C in flag leaf decreased considerably after 24 hours of exposure time when the labelled assimilates were translocated in bulk to the ear head. Under stressed condition a general trend was observed for upward translocation of assimilates towards the ear, even from the stem and root. The percent ¹⁴C activity observed in ear after 24 hours was greatest in severely stressed plants. The photosynthetic rate is reasonable predicted by midday LDR and surface moisture.     

Ritacestus gen. n. (Cestoda: Proteocephalidea) and redescription of R. ritaii comb. n., a parasite of Rita rita (Siluriformes) in India

A new genus, Ritacestus, is proposed to accommodate Ritacestus ritaii (Verma, 1926) comb. n. (syn. Proteocephalus ritaii), a parasite of the catfish Rita rita (Hamilton) in India. The new genus, which is placed in the Gangesiinae, is characterized by (i) a small, subspherical scolex formed by four large lobes separated from one another by longitudinal grooves, with a large, widely oval to pyriform rostellum-like apical organ, larger than suckers and possessing an apical hemispherical depression; (ii) paramuscular and cortical position of some vitelline follicles (most follicles are situated medullary); (iii) ventral and dorsal bands of vitelline follicles usually uninterrupted ventral to terminal genitalia and reaching to the posterior margin of proglottides; (iv) the vagina always anterior to the cirrus-sac; (v) a large size of the body (length up to 51 cm); and (vi) development of the uterus of type 2. In its morphology, especially shape of the scolex and apical organ, and paramuscular and cortical position of some vitelline follicles, Ritacestus resembles Postgangesia Akhmerov, 1969, but differs in the presence of a genital atrium (both genital pores of Postgangesia are separate), the anterior position of the vagina (almost always posterior in the latter genus), position of vitelline follicles in cross sections (dorsal and ventral bands in Ritacestus versus only a lateral band in the latter genus), and dorsal excretory canals indistinguishable in mature and gravid proglottides of R. ritaii (well developed in Postgangesia spp.). The type and only species of the genus, R. ritaii, is redescribed on the basis of new material from the type host from the Ganges River basin in India and its neotype is designated.     

Chemical investigations on the edible seeds of Pentaclethra macrophylla (Benth)

Plant Foods for Human Nutrition -     

Preliminary studies on the seeds ofAnnona muricata Linn.

Soursop (Annona muricata Linn.) seeds were analysed for proximate composition and were found to contain 22.10% pale-yellow oil and 21.43% protein. Physical and chemical characteristics of the seed-kernel oil were determined. Results show that the oil is bland in taste and possesses an acid value of 0.93, a saponification value of 227.48, an iodine value of 111.07 and an acetyl value of 66.77. The oil consists of 28.07% saturated and 71.93% unsaturated fatty acids.     

Notonectids as Live Food for Olive Barb,Puntius Sarana

A feeding experiment was conducted in 40-L tanks each stocked with four fry of olive barb (2.05 ± 0.22 g). Dead notonectids (T1), live notonectids (T2), co-feeding of live notonectids and prepared diet (T3), prepared diet (T4), and plankton concentrate (T5) were fed ad libitum as the five treatments, each maintained with four replications. Proximate composition revealed higher protein and crude lipid contents in both notonectids and plankton concentrate compared to the prepared diet. The insect consumption rate was significantly higher with provision of dead insects (T1), followed by co-feeding of live insect and prepared diet (T3), and the live form (T2) (P < 0.05). Fry showed significantly higher final body weight and net weight gain, as well as specific growth rate, in co-fed group compared to those provided with live or dead insects. Growth performances decreased significantly when fed with prepared diet or plankton concentrate alone. While olive barb fry exhibited a preference for notonectids over the other diets, co-feeding appeared to offer a better nutritional profile for achieving higher growth. The study also indicated possibility of using olive barb as a good candidate for in situ biological control of notonectids during fingerling rearing of barbs and carps.     

Use of maleated castor oil as biomodifier in unsaturated polyester resin/fly ash composites

Maleated castor oil (MACO) was prepared and was used as biomodifier in unsaturated polyester resin (UPE)/fly ash composites. The prepared MACO was characterized for its molecular weight and viscosity. MACO was blended with UPE in three different ratios like 5, 10 and 15 wt%. Fly ash was incorporated in the blend matrix (10 wt%) and curing was done by free radical polymerization. MACO was polymerized and crosslinked with UPE in situ during the formation of the composites. The cured matrix therefore formed an interpenetrating polymer network and the enhancement in properties was significant. Incorporation of 5 wt% MACO was most effective compared to 10 and 15 wt%, when the impact strength increased by 52% without any loss in modulus. The glass transition temperature also shifted to a higher temperature indicating strong intercomponent bonding in this set of composites.