Sultan Qaboos University Scientific Journals
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Role of Biotechnology in Animal Production Systems in Hot Climates
No full textDevelopments in the biological sciences in the last three decades have revolutionized mankind's ability to manipulate the genetics, cell biology and physiology of biological organisms. These techniques, collectively termed biotechnology, create the opportunity for modifying domestic animals in ways that markedly increase the efficiency of production. Among the procedures being developed for animal production systems are marker-assisted selection of specific alleles of a gene that are associated with high production, production of transgenic animals , super ovulation and embryo transfer, in vitro fertilization, embryo sexing and cloning, production of large amounts of previously-rare proteins through use of genetically -engineered bacteria or other cells, and identification of new biologically-active molecules as potential regulators of animal function. To date, most uses of biotechnology have concentrated on problems of general relevance to animal agriculture rather than specific problems related to livestock production in hot climates. However, it is likely that biotechnology will be used for this latter purpose also. Strategies to increase disease resistance using marker-assisted selection, production of transgenic animals expressing viral proteins, and recombinant cytokines to enhance immune function should prove useful to reducing the incidence and seventy of various tropical diseases. Additionally, there are methods to reduce effects of heat stress on oestrus detection and establishment of pregnancy. These include remote sensing of oestrus, ovulation synchronization systems and embryo transfer. More research regarding the physiological processes determining heat tolerance and of the pathways through which heat stress alters physiological function will be required before molecular biology techniques can be used to reduce the adverse effects of heat stress on animal production
Effect of Compositional Grading On reservoir Performance
No full textIn reservoirs with thickness exceeding fifty meters, compositional guiding has been found to cause significant variation in performance. Main fluid properties, governing the magnitude of reservoir performance, such as density; formation volume factor and fluid viscosity experience variation due to varying fluid composition along the hydrocarbon column. These variations cause erroneous estimation of stock-tank oil in place and may infer reservoir engineers to consider inappropriate secondary oil recovery methods, for example. In the presence of gravity segregation within the oil column, heavy ends will form a heavy oil blanket in the lower part of the reservoir. Such a scenario may result in poor displacement and an earlier breakthrough when water drive is the dominant fluid flow mechanism. In this paper reservoir performance due to varying reservoir fluid composition has been examined using reservoir simulation analysis and recommendations for better characterization of reservoir fluid sampling are outlined
Cation Distribution in Natural Chromites from Oman
No full textTwo specimens or natural chromite from the Oman ophiolite were studied using Mossbauer Spectroscopy (MS), X-ray Diffraction (XRD). and Scanning Electron Microscopy (SEM). The diffraction patterns obtained at room temperature showed that the two specimens have a face-centered cubic spinal structure. Their Mossbauer spectra at 295 K. 160 K and 78 K have been fitted to three doublets. assigned to two Fe 2+ at the tetrahedral (A1+,A2) sites and one Fe1+ at the octahedral (B) site. The ferrous-ferric ratio obtained from the Mossbauer analysis together with the atomic concentration derived from the microprobe data are used to derive the chemical formulae for the two specimens. The data also supports also supports a model of ordered caution distribution in the specimens examined
Modern Concrete Wall-Units with Improved Thermal Resistance for Housing in Hot Climate
No full textNew wall-units have been designed at the Civil Engineering Department of SQU, with improved and reliable thermal insulation properties for construction of buildings in hot climatic conditions. as in the Sultanate of Oman. The thermal resistance of many types of concrete units has been analyzed. Hundreds of various types of the new concrete hollow blocks as well as six-column sections made of these wall-units have been tested in full scale. The relationship of compressive strength of the new concrete hollow blocks, walls made of these units and cube samples has been investigated. The wall columns have been tested under axial load and with various eccentricities. The types of column failure have been studied. The aim of the test was to determine the characteristic compressive strength of the new concrete hollow blocks and the characteristic compressive strength of masonry made of these hollow blocks. The results of the test have shown that the new wall-units could have been used Successfully for construction of the walls in buildings
Effect of a Saline Nutritional Regime on Tomato Fruit Yield and on Enhancement of Fruit Quality
No full textThe effect of a saline nutritional regime on tomato (Lycopersicon esculentum Mill.) fruit yield and fruit quality enhancement for five cultivars (CLN 425, Pearson, Napoli, Hymar, and Sierra) was studied. The saline nutrient treatment consisted of (i) a control. Hoagland's solution (EC=2.5 mScm -1), (ii) Hoagland's solution + 50 mM NaCl (EC=7.46 mScm-1), (iii) Hoagland's solution + 50 mM NaCl + 4 mM K2SO4 + 2 mM H3PO4 (EC=8.31mScm-1), (iv) same as in (iii)3 but applied when plants were at 50% flowering, then the plants were irrigated with Hoagland’s solution as in the control, and (v) same as in (iii) until the plans were at 5096 flowering, thereafter NaCl concentration was reduced to 25mM (EC=5.87 mscm-1). Plans were seven weeks old at the start of the saline treatments. Each plant was in PVC cylindrical pots (15 cm diameter and 27 cm height) containing washed quartz sand. Fruits were harvested once weekly for ten weeks at incipient red. The control gave a higher fruit yield than the saline treatments. However, the tomato fruits from thesaline treatments had higher titratable acidity, higher total soluble solids, and higher total solid indicating better quality of the fruits than those from the control. Of the five cultivars studied, Hymar had the highest fruit yield followed by Pearson. Hymar’s quality was also highest, followed by CLN 425. Napoli was the most susceptible to salinity and Sierra had the lowest quality
Contributions to the knowledge of the Biology of the Arabian Abalone Haliotis mariae Wood, 1828
No full textThe Arabian abalone occur in the Arabian Sea’s rocky coastal zone in association with conspicuous macrolgal communities in which it represents the dominant herbivorous component. Despite such ecological importance and although the commercial exploitation of abalone presents a considerable contribution to Omani fisheries, almost nothing is known about the biology of this species. This report presents results of research carried out in the field and with laboratory cultures, and draws general conclusions related also to the fisheries management of these possibly overexploited abalone populations, Cobort observations in the field and measured increments of cultured specimens showed a growth rate significantly higher than in other abalone species, i.e. greater than 3 mm shell-increment per month. The very early sexual maturity demonstrated by captivity spawnings of approximately one year old animals is also quite unusual. The ejected eggs formed mucous mono layers attached to the substratum whereas other abalone species produce pelagic eggs. Jvenile coborts in nature and the periodic spawning of cultured animals indicate the major spawning in spring and postmonsoon one in autumn. The models previously applied in fisheries management of abalone in Oman assumed only one spawning per year, the first being at age 2+, and a slower growth-rate. These models should be reconsidered using the new data, which may partially explain why abalone are less overexploited than one would expect looking at heavy harvesting. In view of a projected commercial abalone cultivation our laboratory rearing experiments showed that both natural and/or artificial food may be used, provided this contains-apart from standard ingredients, the seaweed-borne components (probably phycobillins) required for a normal parasite , resistant shell formation. With regard to artificial reproduction, our preliminary trials showed that spawning , fertilization ,and initial larval rearing present no problems. The steps from the pediveliger to larval settlement, however ,seem to be fatally exposed to eilitate attacks. Further research is needed in order to eliminate this critical problem
Animal Health in the Tropics
No full textMost developing countries in Africa and Asia are located in the tropics (23° north and south of the equator). The poor productivity of ruminants in these countries is mostly due to inadequate nutrition, infectious diseases, low rates of reproduction, poor genotype, high ambient temperatures and socioeconomic constraints. In addition to infectious diseases which have long since been eradicated or brought under control in developed countries, there are diseases unique to the tropical environment. In the past, the diagnosis of most diseases was based on serological tests. The enzyme-linked immunosorbent assay (ELISA), a rapid method of identifying viral and bacterial infections, is contributing to the eradication or control of most epidemic diseases which inflict high mortality. Less attention has; however, been given to subclinical diseases which adversely affect reproduction, growrh rates and reduced performance (draught power, milk and meat). The interaction of veterinary epidemiology and agricultural economics has helped epidemiologists and veterinarians to focus on the economic importance of animal diseases. The emerging trends in animal health include new diagnostic methods using DNA probes, new vaccines, sustainable parasite control schemes and herd health monitoring. The study of infectious diseases of veterinary importance will continue to he supported by modern techniques of molecular biology. Veterinary curricula should emphasis both animal health and production in the context of current national development occurring in the livestock sector
Magnetism in Iron-Zirconium Systems
No full textThe discrete variational method is used to solve the Khon-Sham equation in the spin-polarized local density approximation for Fe-Zr and Fe-Zr-H clusters, representing iron-zirconium and hydrogenated iron-zirconium alloys. The local magnetic moment and hyperfine field at the Fe site were found to decrease, whereas the contact charge density and occupation number were found to increase with Zr contents. The Zr site in clusters with high Fe contents acquires a negative magnetic moment. When H is trapped at an interstitial site next-neighboring an Fe atom, the magnetic moment and hyperfine field are enhanced, while the contact charge density is reduced. ‘The opposite occurs when H occupies a neighboring interstitial site to Fe. For Zr atoms the local magnetic moment is found to become less negative with H at the neighboring position. We conclude from this calculation that H is trapped in Fe-Zr systems at positions which are nearest to Zr and next-nearest to Fe atoms