ALBERT

Description: This paper deals with the development of the flow in a curved tube near the inlet. The solution is obtained by the method of matched asymptotic expansions. Two inlet conditions are considered: (i) the condition of constant dynamic pressure at the entrance, which may be of practical interest in applications to blood flow in the aorta; and (ii) a uniform entry condition. It is shown that the geometry and the nature of the entry condition appreciably influence the initial development of the flow. The effect of the secondary flow due to the curvature on the wall shear is discussed and it is shown that the cross-over between shear maxima on the inside and the outside of the tube occurs at a downstream distance which is 1·9 times the radius of the tube for entry condition (i) while in the case of entry condition (ii) it is 0·95 times the radius, which is half the distance required in case (i). It is found that the pressure distribution is not significantly influenced by the secondary flow during the initial development of the motion. The analysis, which is developed for steady motion, can be extended to pulsatile flows, which are of greater physiological interest. © 1974, Cambridge University Press. All rights reserved.

Description: This paper supplements an earlier study (Singh 1974) of the steady case of ‘Entry flow in a curved pipe’. Here we consider an entrance profile of the form formula omitted which is physiologically more relevant for blood being pumped from the left ventricle into the ascending aorta. A boundary-layer analysis is applied to determine the effects of curvature and an adverse pressure gradient (associated with the primary flow) on the wall shear. The study shows how the negative wall shear and backflow near the wall develop during the decelerating phase of the cycle as the boundary layer grows. The analysis shows how the increasing effect of the secondary flow due to curvature draws off slower moving fluid azimuthally from the outer bend to the inner bend; this induces a cross-flow of faster moving fluid from the inner bend to the outer bend which results in a thinning of the boundary layer at the outer bend and a thickening at the inner bend. This implies an increased wall shear at the outer bend compared with that at the inner bend as the flow develops further downstream; this is in contrast with the initial stages of the motion near the entrance where the higher wall shear occurs at the inner bend owing to the external flow and to geometric factors. The analysis shows that the displacement effect of the boundary layer on the core is not significant because the boundary layer remains thin, about one-tenth of the tube diameter. © 1978, Cambridge University Press. All rights reserved.

Description: Although sheep combat thermal stress mainly by panting, a sizeable amount (40%) of total evaporative heat loss, is from sources other than panting (Hales & Brown, 1974). The frequency of sporadic discharge of sweat glands increases with increase in ambient temperature and is accompanied by a decline in respiration rate (Bligh, 1961). The wool coat can reduce evaporative cooling but sweating may have cooling value in sheep breeds with open fleeces (Rai, Singh & More, 1978). In sheep, the number and size of the sweat glands (Waites & Voglmayr, 1962) and the quantum of sweat production in a particular time period (Ghoshal et al. 1977) varies in different body regions. In view of the possible significance of surface evaporative cooling, thermal sweating in different body regions of sheep was investigated.

Description: Yellowing of wool as a function of physiological stress caused by nutritional deficiency in the feed of sheep (Das, 1965) though not confirmed by subsequent studies (Singh et al. 1977) evoked interest in the role of physiological stress in causing canary staining of wool. Restricted water intake as is generally the case with sheep in arid or even semiarid regions during summer, imposes considerable physiological stress. Furthermore, canary coloration is thought to be a sequel to an adaptive mechanism to hot and humid conditions in Indian sheep which have a greater reliance on cutaneous evaporation for dissipating body heat (Acharaya & Singh, 1976). It was, therefore, decided to study the influence, if any, of restricting access to water on the canary coloration of wool (non-scourable yellow coloration of the autumn clip) in the stain-susceptible Chokla sheep

Description: SUMMARYOne hundred and eighty triple test cross families arising from three barley crosses (C 164 x EB 1556, BG 25 x NP 21 and BH 15 x RD 103) were grown in two blocks of a randomized-block design in saline-alkali soil prepared in micro-plots. The families were evaluated for number of days from sowing to heading, plant height, number of tillers per plant, ear length, number of grains per ear, 100-grain weight and grain yield per plant. The cross BG 25 x NP 21 showed epistasis only for number of days toheading and number of grains per ear; in contrast, epistasis was present in all traits in BH 15 x RD 103. In cross C 164 x EB 1556, epistasis was detected for plant height, ear length and number of grains per ear. Thus, epistasis appears to be related to specific cross combination. The ‘j and l’ type epistasis was more pronounced than the ‘i’ type. Early generation selection may be used for number of days to heading which Exhibited epistasis marginally with preponderance of additive gene effects, while for the remaining traits selection should be deferred till an advanced generation.

Description: SummaryField investigations conducted at Ludhiana (India) showed that the foliar application of 2-chloroethyltrimethyl-ammonium chloride (CCC) (50% a.i.) at 300,600 and 900 ml/ha about 5 weeks after planting did not depress plant height. The dose of 600 ml CCC/ha was most effective and increased seed yield by 1·31 and 0·74 t/ha over the control (water spray) in 1978–9 and 1979–80, respectively. The corresponding increases in total yield were 1·37 and 0·86 t/ha. However, in 1980–1 when CCC was applied 3 weeks after planting even the lower dose of 300 ml/ha depressed the plant height. Then the treatment of CCC increased significantly the number of tubers of seed size and seed yield by decreasing the ‘ware’ yield but did not influence the total yield. The yields of potatoes were not affected signifioantly by the application of N-dimethyl amino succinamic acid (B 9) and succinic acid (SA).In an experiment where the interaction of nitrogen and CCC was studied both factors not only increased the seed yield but also increased the total yield. However, there was no interaction between nitrogen and CCC.

Description: Periwinkle (Catharanthus roseus (L.) G. Don) is an important medicinal plant grown in different parts of India. Its leaves contain vincristine and vinblastin, alkaloids which are used in the treatment of various leukaemias and limphomas, and its roots contain ajmalcine, another alkaloid, used in the manufacture of antihypertensive drugs. Cultivation of periwinkle has recently gained importance in India. The yield of periwinkle can be increased with the use of mineral fertilizers (Pareek et al. 1981, 1982; Rajasekharan et al. 1982; Reghunath & Sethumadhavan, 1982a, b; Hegde, 1986). The effect of fertilizer application on the alkaloid concentration is not clearly established though there are a few reports which suggest that application of N increases alkaloid concentration in roots (Rajasekharan et al. 1982; Reghunath & Sethumadhavan, 1982a) and leaves (Pareek et al. 1982). Therefore, the present experiment was designed to study the effect of application of nitrogen and phosphatic fertilizers and farmyard manure on the root and leaf yields, and total alkaloid concentrations in roots and leaves in Catharanthus roseus (L.) G. Don.

Description: SUMMARYTrials were established at two sites in 1982 to compare six 2-course rotations, in which barley alternated with feed legumes (pure or mixed with barley), fallow or barley, in partial factorial combination with different N and P fertilizer regimes. This paper summarizes data from the second to the seventh cropping seasons.Barley yielded most after fallow and more after legumes than after barley; but, on the basis of total dry matter production over both courses, barley-legume rotations outyielded barley-fallow and barley-barley rotations. In terms of net nitrogen offtake, which may be taken as a rough measure of feed value, barley-legumes surpassed the other rotations by c. 100% at both sites, whether the comparison was made on values obtained from plots with or without added fertilizer. Of the legumes, Lathyrus sativus was slightly more productive than Vicia saliva, and this carried over into the rotational yield of both dry matter and nitrogen. Rotations involving pure legumes were slightly more productive than those involving legume/barley mixtures.Yields of all crops and rotations varied greatly from year to year depending on rainfall. Those of the barley-fallow rotation were much less variable than those of the barley-barley rotation at the wetter site (323±103 mm), with the barley-legume rotation intermediate; but variability was much greater at the drier site (250±79 mm), with much less difference between rotations. Nevertheless, fertilizer use and rotations including legumes gave a significant yield advantage under the driest conditions.

Description: Two field experiments were conducted during 1996–98 at Bangalore, India to study the effect of soil moisture regimes (0·3, 0·6 and 0·9 IW:CPE ratios) irrigation water:cumulative pan evaporation (IW:CPE) ratios and three rates of nitrogen application (0, 100 and 200 kg/ha) and in another experiment, three soil moisture regimes (0·3, 0·6 and 0·9 IW: CPE ratios), two rates of nitrogen application (100 and 200 kg/ha) and modified urea materials [prilled urea (PU) and dicyandiamide coated urea (DCDCU)] on oil content, herbage, oil yield and quality of geranium grown on altisols. Soil moisture maintained at 0·6 IW:CPE ratio significantly increased the herbage and oil yields of geranium. Application of 200 kg N/ha gave the maximum herbage and oil yield compared with those obtained from 0 and 100 kg N/ha. DCDCU produced higher yield than PU. The concentration and quality of essential oil were not influenced either by soil-moisture regime, rates or carriers of N.

Description: Trials, reflecting the feed needs in dry Mediterranean environments of small-ruminant production systems based on barley, were established at two sites in Syria in 1982. They compared various 2-course rotations of barley with feed legumes, fallow or more barley. This paper summarizes a 14-year sequence of results from an incomplete factorial combination of four rotations (B-V, B-L, B-F, B-B) of barley with vetch (Vicia sativa), lathyrus (Lathyrus sativus), fallow, and barley, with two fertilizer regimes, zero control and biennial NP applied to the barley phase, in terms of long-term mean yields, production stability and yield trends over time.On a 2-year rotational basis, most barley was produced by barley-only rotations, and differences between B-F and B-B were small; but, in terms of total biomass production, feed legume rotations (B-V and B-L) outyielded barley-only rotations by 29% at one site and 19% at the other. Responses to biennial fertilization were large but did not interact significantly with rotation treatment. The crude protein status (%N) of barley grain and straw was strongly determined by seasonal rainfall, but that of the grain could be enhanced, irrespective of rainfall, by a preceding feed-legume crop; and, altogether, the total mean crop nitrogen output of legume-based rotations exceeded that of barley-only rotations by 80% and 64% at the two sites. The inclusion of legumes thus enhances both quantity and quality of feed production.Annual yield fluctuations, attributable mainly to rainfall difference, were greater at the drier site. No consistent effect from fertilizer was observed, but at the wetter site rotation differences were appreciable, with B-F rotation giving the most stable yields. A number of time trends in yield values were tentatively identified. On a relative basis, some widening over time of the gap between fertilized and unfertilized treatments was observed in feed-legume yields at both sites and barley yields at the wetter site; over 14 years, yields in unfertilized plots had apparently declined relative to those receiving biennial NP. But, apart from a probable decline in lathyrus productivity compared to that of common vetch, changes in relative yield performance between rotations were difficult to detect. Regression models developed to describe absolute yield trends indicated a real decline over time in barley grain yields in continuous barley (B-B) at both sites and in unfertilized plots of all four rotations at the wetter site.