2,095 research outputs found
The domestic resource cost concept: Theory and an empirical application to the case of Spain
The problem of how to make an optimum use of a country's limited productive resources is often a crucial one to the policy makers in less developed countries (LDCs). Not surprisingly, therefore, the various methods of cost-benefit analysis have attracted much attention among professional economists and are finding a wide spread application in evaluating the social profitability of investment projects and in the planning decision-making process as well. Relatively less attention has been paid to yet another criterion of project appraisal in a developing country that has been developed independently of social cost benefit analysis - the so called domestic resource cost (DRC) approach to project appraisals. This approach is properly regarded as the application of the propositions of allocation theory when the project, or the industry in question, produces (or saves) foreign exchange. The DRC concept compares the opportunity costs of domestic resources (primary factors such as labour, capital, land) conmitted to the production of final goods with prices at which these goods can be exported or imported - the latter prices (the foreign exchange gained or saved) being considered as the ensuing benefits from production. The rationale for using the foreign exchange gained (through exports) or saved (through imports) as a standard of reference is that foreign exchange is relatively, and often critically, scarce in many developing countries.
On an alternative representation for a wide class of binary relations
It is shown that any antireflexive binary relation which is either transitive or symmetric can be represented by a specific tree structure whose nodes are of maximum order 3. The relationship between this representation and an analogous representation for a narrower class of relations (previously called “splitting”) is discussed. Algorithms are developed for obtaining the tree structures from a matrix representation
On the Origin of the Third Ionospheric Echo
There is still some difference of opinion regarding the ray, ordinary or
extraordinary, to which the so-called third or Z-component of the ionospheric echoes correspond, It is pointed out in the paper that there need be no controversy on the
subject because, as first clearly shown by Bhar, the branch of the dispersion curve which passes through the ''point'' of reflection of the Z-component is really an ordinary branch. Calculations arc further carried out to determine the retardation that the extraordinary ray
would suffer, if it were able to partially penetrate its first point of reflection, in its passage into regions of higher electronic densities. It is found that the retardation on reaching the asymptote of the dispersion curve would become infinite, so that, the extraordinary ray, under no circumstances, is able to penetrate the barrier, One is thus forced to the
alternative that it is the ordinary ray which provides the Z-component in the ionospheric echo pattern
Enhancement in thermoelectric power in lead telluride nanocomposite: role of oxygen vis-a-vis nanostruct
The present work reports enhanced power factor and reduced value of room temperature thermal conductivity in undoped PbTe nanocomposite, prepared from PbTe nanocrystals, synthesized via chemical route. The highest power factor is found to be
19.21 ´ 10 –4 Wm –1K –2 with room temperature thermal conductivity of 1.53 Wm –1K –1. The potential barrier at the sharp interfaces of the grains of the nanocomposites,
occurred due to the adsorption of oxygen by the grain surfaces, have been found to play the main role to produce the high value of Seebeck coefficient (416 mV/K at 500 K) by preferentially scattering the lower energy electrons and thus enhancing the power factor. The lattice destruction at the grain interfaces has been found to cause the remarkable reduction in thermal conductivity, through scattering a wide spectrum of
phonon wavelength.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2205
Influence of Growth Regulators and Explant on Plant Regeneration in Tomato
Influence of different growth regulators was studied on in vitro growth and regeneration of tomato (Solanum esculentum) explants derived from hypocotyls and cotyledons of aseptically grown seedlings. On the basis of regeneration frequency, number of shoot primordia and shoots produced per explants, it is concluded that the best regeneration is achieved on Murashige and Skoog (MS) medium supplemented with 0.5 mg L"1 of indole-3-acetic acid and 1.0 mg L"1 zeatin. In all the genotypes studied, a good percentage of regeneration frequency was observed in hypocotyl explants used
Density-and trait-mediated effects of a parasite and a predator in a tri-trophic food web
1. Despite growing interest in ecological consequences of parasitism in food webs, relatively little is known about effects of parasites on long-term population dynamics of non-host species or about whether such effects are density- or trait- mediated.
2. We studied a tri-trophic food chain comprised of: (i) a bacterial basal resource (Serratia fonticola), (ii) an intermediate consumer (Paramecium caudatum), (iii) a top predator (Didinium nasutum), and (iv) a parasite of the intermediate consumer (Holospora undulata). A fully-factorial experimental manipulation of predator and parasite presence/absence was combined with analyses of population dynamics, modelling, and analyses of host (Paramecium) morphology and behavior.
3. Predation and parasitism each reduced the abundance of the intermediate consumer (Paramecium), and parasitism indirectly reduced the abundance of the basal resource (Serratia). However, in combination, predation and parasitism had non-additive effects on the abundance of the intermediate consumer, as well as on that of the basal resource. In both cases, the negative effect of parasitism seemed to be effaced by predation.
4. Infection of the intermediate consumer reduced predator abundance. Modelling and additional experimentation revealed that this was most likely due to parasite reduction of intermediate host abundance (a density-mediated effect), as opposed to changes in predator functional or numerical response.
5. Parasitism altered morphological and behavioural traits, by reducing host cell length and increasing the swimming speed of cells with moderate parasite loads. Additional tests showed no significant difference in Didinium feeding rate on infected and uninfected hosts, suggesting that the combination of these modifications does not affect host vulnerability to predation. However, estimated rates of encounter with Serratia based on these modifications were higher for infected Paramecium than for uninfected Paramecium.
6. A mixture of density-mediated and trait-mediated indirect effects of parasitism on non- host species creates rich and complex possibilities for effects of parasites in food webs that should be included in assessments of possible impacts of parasite eradication or introduction
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Development of low cost packaged fibre optic sensors for use in reinforced concrete structures
There is an ongoing need to measure strains in reinforced concrete structures more reliably and under a range of circumstances e.g. long term durability (such as effects of cracking and reinforcement corrosion), response to normal working loads and response under abnormal load conditions. Fibre optic sensors have considerable potential for this purpose and have the additional advantages, including of immunity to electromagnetic interference and light weight (Grattan et al., 2000). This is important in railway scenarios and particularly so when the lines are electrified. Their small size allows for easy installation. However, their use as commercial ‘packaged’ devices (traditionally seen as necessary to achieve adequate robustness) is limited by their high cost relative to other sensor devices such as encapsulated electric resistance strain gauges. This paper describes preliminary work to produce a cost-effective and easy-to-use technique for encapsulating fibre optic sensors in resin using 3D printing techniques to produce a robust, inexpensive ‘packaged’ sensor system suitable for use with concrete structures. The work done to date has shown this to be a convenient and economical way of producing multiple sensors which were suitable for both surface mounting and embedment in reinforced concrete structures. The proof-of-concept testing to which the trial packages were subjected is described in the paper and the results indicate that 3D printed packages have considerable potential for further development and use in a variety of civil engineering applications, competing well with more conventional sensor systems
Morphological and Biochemical Characterization of Chrysanthemum
Ten large flowered chrysanthemum cultivars, viz., 'Beat Rice May', 'Beauty', 'Casa Grande', 'Jet Snow', 'John Weber' , 'Miss Maud Jeffries', 'Penny Lane', 'Shanker Dayal', 'Snow Ball' and 'S.S. Arnold' from National Botanical Research Institute (NBRI), Lucknow, were evaluated for morphological and biochemical characterization. Morphological data were recorded on vegetative and floral characters. Biochemical characterization included analysis of anthocyanins, carotenoides, chlorophyll content (chlorophyll a, b and total) and flavonoids. Results on morphological and biochemical parameters clearly indicated distinctness among cultivars with reference to differences in morphological characters and chemical composition of pigments
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