The concept of availability incorporates both the notions of reliability and maintainability. Wit... more The concept of availability incorporates both the notions of reliability and maintainability. With exponential failure and repair time models, the availability ratio is defined as the ratio of the failure rate to the repair rate. This ratio is also known as the service factor in queuing ...
Engineering systems are subject to continuous stresses and shocks which may (or may not) cause a ... more Engineering systems are subject to continuous stresses and shocks which may (or may not) cause a change in the failure pattern of the system with unknown probability q( = 1 -p), 0 <p < 1. Conceptualising a mixture of hazard-rate or failure-rate patterns representing a realistic situation, the failure time distribution is given in the corresponding case. Classical and Bayesian estimation of the parameters and reliability characteristics of this failure time distribution is the subject matter of the present study.
This paper develops the asymptotic sampling distribution of the inverse of the coefficient of var... more This paper develops the asymptotic sampling distribution of the inverse of the coefficient of variation (InvCV). This distribution is used for making statistical inference about the population CV (coefficient of variation) or InvCV without making an assumption about the population distribution. It applies to making inferences (point and interval estimation, and hypothesis-testing) about the shape parameter of some popular lifetime distributions like the Gamma, Weibull, and log-normal, when the scale parameter is unknown. The test procedure is used to test exponentiality against a Gamma or a Weibull alternative. The results are compared with those in the literature
Nutrient elements and lipoxygenase (LOX) activity were determined in strawberry fruit to establis... more Nutrient elements and lipoxygenase (LOX) activity were determined in strawberry fruit to establish a relationship, if it exists, between nutrient ratios (N/Ca and K/Ca), and lipoxygenase activity with albinism disorder. About 33% strawberry fruit were affected by albinism. Etna had highest incidence of albinism (48.6%) and Sweet Charlie the lowest (16.2%). Dry matter content (%) was lower in albino fruit (5.23%) than normal fruit (7.36%). The concentration of N, P, and Mg did not differ significantly, but that of K (1.87 mg g À1 fresh weight) was notably higher and of Ca (0.105 mg g À1 fresh weight) was lower in albino fruit than normal fruit. Consequently, the nutrient ratios, N/Ca (9.78) and K/ Ca (16.96) were higher in albino fruit than normal fruit. Cultivars differed widely in respect to dry matter (%), mineral content and nutrient ratios. LOX activity determined on dry weight or fresh weight basis was significantly higher in albino fruit than normal fruit, with significant differences among cultivars. Positive correlations existed between nutrient ratios and albinism incidence (r = +0.338), LOX activity and albinism incidence (r = +0.412), and LOX and nutrient ratios (r = +0.448). Thus, it appears from the study that calcium and LOX activity may not the basic cause of albinism in strawberry, but these may be involved in senescence or fruit ripening process, as LOX activity was lower in albino than in normal fruit. #
A study was conducted in strawberry to establish a relationship between shading, mineral nutrient... more A study was conducted in strawberry to establish a relationship between shading, mineral nutrient of leaves and fruits with albinism incidence. Plants grown under shade produced albino fruits in higher proportion than those grown in open fields. Similarly, plants under shade produced smaller sized fruits and have lower fruit yield. Among cultivars, Etna had highest incidence of albinism (49.6%) and Sweet Charlie the lowest (14.4%). Dry matter content (%), concentration of five major nutrients, viz. N, P, K, Ca, Mg, S and N:Ca and K:Ca nutrient ratios did not differ significantly in the leaves of plants producing normal or albino fruits. However, in contrast, the concentration of K was notably higher (1.97 mg g À1 fresh tissue weight) and that of Ca was lower (0.098 mg g À1 fresh tissue weight) in albino fruits than normal ones. Consequently, the ratios of N:Ca (11.34) and K:Ca (20.08) were higher in albino fruits than normal ones. Cultivars also differed widely in respect to dry matter (%), mineral content and nutrient ratios. Thus, it appears that lower light intensity favours the development of albinism in strawberry, and it seems that calcium is not the basic cause of albinism, but increased vigour associated with overuse of N and K might be positively associated with it. #
Biotechnology can complement conventional breeding and expedite the mango improvement programmes.... more Biotechnology can complement conventional breeding and expedite the mango improvement programmes. Studies involving in vitro culture and selection, micropropagation, embryo rescue, genetic transformation, marker-assisted characterization and DNA fingerprinting, etc. are underway at different centers worldwide. In vitro culture and somatic embryogenesis of several different genotypes have been achieved. The nucellus excised from immature fruitlets is the appropriate explant for induction of embryogenic cultures. High frequency somatic embryogenesis has been achieved in some genotypes; however, some abnormalities can occur during somatic embryo germination. Embryo rescue from young and dropped fruitlets can improve the hybridization success in a limited flowering season. Protocols for protoplast culture and regeneration have also been developed. In vitro selections for antibiotic tolerance and fungal toxin resistance have been very promising for germplasm screening. Genetic transformation using Agrobacterium tumefaciens has been reported. Genes that are involved with fruit ripening have been cloned and there have been attempts to deliver these genes into plants. DNA fingerprinting and studies on genetic diversity of mango cultivars and Mangifera species are also being conducted at several research stations. The purpose of this review is to focus upon contemporary information on biotechnological advances made in mango. It also describes some ways of overcoming the problems encountered during in vitro propagation of mango.
Improved establishment of mycorrhizal tissue culture derived plantlets during acclimatization (St... more Improved establishment of mycorrhizal tissue culture derived plantlets during acclimatization (Stage IV) is commonly attributed to the enhanced vegetative growth as a resultant of different morphological and in vivo changes. These changes are early and better cuticle development, high biomass accumulation, enhanced physiological changes, improved mineral nutrition, especially phosphorus and micronutrients, etc. However, improvement in establishment of micropropagated plantlets during acclimatization may not only be limited to these mechanisms. In the present investigation, biochemical status of micropropagated grape plantlets in response to six single and a mixed strains of arbuscular-mycorrhizal fungi (AMF) during hardening were studied under glasshouse conditions. The histochemical studies revealed that the mycorrhizal inoculation resulted in accumulation of different biochemicals in the plant system such as chlorophyll, carotenoids, proline, phenol and enzymes like polyphenol oxidase (PPO) and nitrate reductase (NR). The mycorrhizal plantlets showed enhanced survival and improved tolerance against stresses experienced during weaning phase. The mycorrhizal plants also exhibited improved physiological and nutritional status and had higher relative water content (RWC) and photosynthetic rate. These plantlets also accumulated higher N, P, Mg and Fe concentrations, which may primarily be as a result of biochemical changes brought about by mycorrhizal association. Mycorrhizal plantlets also showed www.elsevier.com/locate/scihorti Scientia Horticulturae 106 better hardening under glasshouse conditions. The result suggests that the biochemical changes brought about by mycorrhization were helpful in mitigating different stresses experienced by the tissue culture plants during hardening, which determine their performance later in field. #
The in vitro performance of mango shoot culture is delimited by several factors, of which explant... more The in vitro performance of mango shoot culture is delimited by several factors, of which explant necrosis and media browning are considered as major constraints for successful exploitation of such an important commercial crop. Our results showed that source of explants had a ...
The concept of availability incorporates both the notions of reliability and maintainability. Wit... more The concept of availability incorporates both the notions of reliability and maintainability. With exponential failure and repair time models, the availability ratio is defined as the ratio of the failure rate to the repair rate. This ratio is also known as the service factor in queuing ...
Engineering systems are subject to continuous stresses and shocks which may (or may not) cause a ... more Engineering systems are subject to continuous stresses and shocks which may (or may not) cause a change in the failure pattern of the system with unknown probability q( = 1 -p), 0 <p < 1. Conceptualising a mixture of hazard-rate or failure-rate patterns representing a realistic situation, the failure time distribution is given in the corresponding case. Classical and Bayesian estimation of the parameters and reliability characteristics of this failure time distribution is the subject matter of the present study.
This paper develops the asymptotic sampling distribution of the inverse of the coefficient of var... more This paper develops the asymptotic sampling distribution of the inverse of the coefficient of variation (InvCV). This distribution is used for making statistical inference about the population CV (coefficient of variation) or InvCV without making an assumption about the population distribution. It applies to making inferences (point and interval estimation, and hypothesis-testing) about the shape parameter of some popular lifetime distributions like the Gamma, Weibull, and log-normal, when the scale parameter is unknown. The test procedure is used to test exponentiality against a Gamma or a Weibull alternative. The results are compared with those in the literature
Nutrient elements and lipoxygenase (LOX) activity were determined in strawberry fruit to establis... more Nutrient elements and lipoxygenase (LOX) activity were determined in strawberry fruit to establish a relationship, if it exists, between nutrient ratios (N/Ca and K/Ca), and lipoxygenase activity with albinism disorder. About 33% strawberry fruit were affected by albinism. Etna had highest incidence of albinism (48.6%) and Sweet Charlie the lowest (16.2%). Dry matter content (%) was lower in albino fruit (5.23%) than normal fruit (7.36%). The concentration of N, P, and Mg did not differ significantly, but that of K (1.87 mg g À1 fresh weight) was notably higher and of Ca (0.105 mg g À1 fresh weight) was lower in albino fruit than normal fruit. Consequently, the nutrient ratios, N/Ca (9.78) and K/ Ca (16.96) were higher in albino fruit than normal fruit. Cultivars differed widely in respect to dry matter (%), mineral content and nutrient ratios. LOX activity determined on dry weight or fresh weight basis was significantly higher in albino fruit than normal fruit, with significant differences among cultivars. Positive correlations existed between nutrient ratios and albinism incidence (r = +0.338), LOX activity and albinism incidence (r = +0.412), and LOX and nutrient ratios (r = +0.448). Thus, it appears from the study that calcium and LOX activity may not the basic cause of albinism in strawberry, but these may be involved in senescence or fruit ripening process, as LOX activity was lower in albino than in normal fruit. #
A study was conducted in strawberry to establish a relationship between shading, mineral nutrient... more A study was conducted in strawberry to establish a relationship between shading, mineral nutrient of leaves and fruits with albinism incidence. Plants grown under shade produced albino fruits in higher proportion than those grown in open fields. Similarly, plants under shade produced smaller sized fruits and have lower fruit yield. Among cultivars, Etna had highest incidence of albinism (49.6%) and Sweet Charlie the lowest (14.4%). Dry matter content (%), concentration of five major nutrients, viz. N, P, K, Ca, Mg, S and N:Ca and K:Ca nutrient ratios did not differ significantly in the leaves of plants producing normal or albino fruits. However, in contrast, the concentration of K was notably higher (1.97 mg g À1 fresh tissue weight) and that of Ca was lower (0.098 mg g À1 fresh tissue weight) in albino fruits than normal ones. Consequently, the ratios of N:Ca (11.34) and K:Ca (20.08) were higher in albino fruits than normal ones. Cultivars also differed widely in respect to dry matter (%), mineral content and nutrient ratios. Thus, it appears that lower light intensity favours the development of albinism in strawberry, and it seems that calcium is not the basic cause of albinism, but increased vigour associated with overuse of N and K might be positively associated with it. #
Biotechnology can complement conventional breeding and expedite the mango improvement programmes.... more Biotechnology can complement conventional breeding and expedite the mango improvement programmes. Studies involving in vitro culture and selection, micropropagation, embryo rescue, genetic transformation, marker-assisted characterization and DNA fingerprinting, etc. are underway at different centers worldwide. In vitro culture and somatic embryogenesis of several different genotypes have been achieved. The nucellus excised from immature fruitlets is the appropriate explant for induction of embryogenic cultures. High frequency somatic embryogenesis has been achieved in some genotypes; however, some abnormalities can occur during somatic embryo germination. Embryo rescue from young and dropped fruitlets can improve the hybridization success in a limited flowering season. Protocols for protoplast culture and regeneration have also been developed. In vitro selections for antibiotic tolerance and fungal toxin resistance have been very promising for germplasm screening. Genetic transformation using Agrobacterium tumefaciens has been reported. Genes that are involved with fruit ripening have been cloned and there have been attempts to deliver these genes into plants. DNA fingerprinting and studies on genetic diversity of mango cultivars and Mangifera species are also being conducted at several research stations. The purpose of this review is to focus upon contemporary information on biotechnological advances made in mango. It also describes some ways of overcoming the problems encountered during in vitro propagation of mango.
Improved establishment of mycorrhizal tissue culture derived plantlets during acclimatization (St... more Improved establishment of mycorrhizal tissue culture derived plantlets during acclimatization (Stage IV) is commonly attributed to the enhanced vegetative growth as a resultant of different morphological and in vivo changes. These changes are early and better cuticle development, high biomass accumulation, enhanced physiological changes, improved mineral nutrition, especially phosphorus and micronutrients, etc. However, improvement in establishment of micropropagated plantlets during acclimatization may not only be limited to these mechanisms. In the present investigation, biochemical status of micropropagated grape plantlets in response to six single and a mixed strains of arbuscular-mycorrhizal fungi (AMF) during hardening were studied under glasshouse conditions. The histochemical studies revealed that the mycorrhizal inoculation resulted in accumulation of different biochemicals in the plant system such as chlorophyll, carotenoids, proline, phenol and enzymes like polyphenol oxidase (PPO) and nitrate reductase (NR). The mycorrhizal plantlets showed enhanced survival and improved tolerance against stresses experienced during weaning phase. The mycorrhizal plants also exhibited improved physiological and nutritional status and had higher relative water content (RWC) and photosynthetic rate. These plantlets also accumulated higher N, P, Mg and Fe concentrations, which may primarily be as a result of biochemical changes brought about by mycorrhizal association. Mycorrhizal plantlets also showed www.elsevier.com/locate/scihorti Scientia Horticulturae 106 better hardening under glasshouse conditions. The result suggests that the biochemical changes brought about by mycorrhization were helpful in mitigating different stresses experienced by the tissue culture plants during hardening, which determine their performance later in field. #
The in vitro performance of mango shoot culture is delimited by several factors, of which explant... more The in vitro performance of mango shoot culture is delimited by several factors, of which explant necrosis and media browning are considered as major constraints for successful exploitation of such an important commercial crop. Our results showed that source of explants had a ...
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