Showing papers by "National University of Singapore published in 1970"
TL;DR: In this paper, the effect of predetection bandwidth restriction on the error performance of binary frequency modulation (FM) systems for various frequency deviations has been investigated with an examination of the probability of bit error.
Abstract: The spectra of digital frequency modulation (FM) signals have been observed to be narrow compared with the spectra of digital baseband signals or the corresponding amplitude modulation (AM) and phase modulation (PM) signals. This suggests a high efficiency of transmission in terms of occupied bandwidth for binary FM. Here the desirability of digital FM systems is investigated further with an examination of the probability of bit error. The FM receiver considered consists of a predetection filter, a limiter-discriminator, and a postdetection filter. New results are presented on the effect of predetection bandwidth restriction on the error performance of binary FM systems for various frequency deviations. Theoretical results have been obtained by a Fourier analysis of the distorted FM signals and by Rice's click analysis of FM noise. The data presented permits an optimum selection of system parameters such as frequency deviation ratio and predetection filter bandwidth. It is found that in narrow-band operation a peak-to-peak frequency deviation of about 0.7 times the bit rate and a bandpass filter bandwidth of about 1.0 times the bit rate yield a minimum probability of error. Experimental measurements have been made and there is, in general, good agreement with the theory. A comparison of the error performance of noncoherent binary FM, coherent AM, and coherent PM in a restricted band is made. Narrow-band noncoherent FM proves superior to AM in any bandwidth. In narrow-band operation, the noncoherent FM gives a somewhat better error performance than the coherent PM. For example, for an error rate of 10-4and a bandpass filter bandwidth of one times the bit rate, the performance of a noncoherent FM system is 0.7 dB better than that of a coherent PM system.
116 citations
TL;DR: It has been possible to exclude the presence of fragments of α‐chain longer than II residues in the cells of these infants, and studies indicate that the syndrome results from a total deficiency ofα‐chain production.
Abstract: Summary. The haemoglobin constitution of 14 infants with the haemoglobin Bart's hydrops syndrome has been examined. Thirteen of the infants were stillborn or lived only a few minutes after delivery, but in one case an exchange transfusion was performed and the pattern of globin chain synthesis examined by an [H3]leucine incorporation experiment utilizing umbilical cord blood. These studies indicate that the syndrome results from a total deficiency of α-chain production. Furthermore, it has been possible to exclude the presence of fragments of α-chain longer than II residues in the cells of these infants.
In each infant a small quantity of haemoglobin was found which consisted of normal γ-chains in association with chains of unique constitution. A similar component was found in trace amounts in normal umbilical cord blood. This haemoglobin may be identical with haemoglobin Portland. It is suggested that the non-γ-chain of this haemoglobin is the product of a normal foetal haemoglobin locus which produces very small amounts of gene product in normal infants but which is capable of increased activity in the presence of a partial or total deficiency of α-chains.
107 citations
TL;DR: Bradykinin is inactivated on transit through the pulmonary circulation, but other peptides such as angiotensin II, polistes kinin11 and eledoisin3,4 pass through without loss.
Abstract: THE lung has many important metabolic functions1,2 which include the selective activation or inactivation of endogenous peptides. Bradykinin is inactivated on transit through the pulmonary circulation3,4, probably by at least two endopeptidases5, but other peptides such as angiotensin II (refs. 6–10), polistes kinin11 and eledoisin3,4 pass through without loss.
97 citations
TL;DR: In this paper, an algorithm based on the variable gradient method for the construction of Lyapunov functions is proposed, which is applicable to the particular class of second-order systems with state variables expressible both in the form of trigonometrical functions and polynomials.
Abstract: An algorithm based on the variable gradient method for the construction of Lyapunov functions is proposed. This algorithm is applicable to the particular class of second-order systems with state variables expressible both in the form of trigonometrical functions and polynomials; and the extension to third-order systems appears to be possible.
54 citations
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01 Jan 197053 citations
TL;DR: Butterfly rash, alopecia and photosensitive lesions were slightly more common than in Western series, whereas, Raynaud's phenomenon, discoid lesions and others were rarely found.
Abstract: SUMMARY
Sixty two cases of SLE were studied in a Medical Unit for a period of 4 years. Four different aspects of the cutaneous manifestations were analyzed and discussed. Butterfly rash, alopecia and photosensitive lesions were slightly more common than in Western series, whereas, Raynaud's phenomenon, discoid lesions and others were rarely found. Some other uncommon lesions, especially one case with bullae formation, one with gangrene of toe and another with subcutaneous calcinosis, were observed. Psoriasiform lesions and hyperkeratotic lesions were also found in this series.
Skin lesions secondary to systemic disorders and therapy were also studied and the findings discussed.
24 citations
TL;DR: A survey of Fusarium in the cultivated and uncultivated soils of Singapore showed the presence of F. solani, which was recovered in highest numbers per g of soil, while F. episphaeria was lowest, and rarely found in uncultivating soils.
Abstract: A survey of Fusarium in the cultivated and uncultivated soils of Singapore showed the presence ofF. episphaeria, F. oxysporum, F. roseum andF. solani. The total population of Fusarium was small in uncultivated soils, some of which did not show any Fusarium, but much larger in cultivated soils.F. solani was recovered in highest numbers per g of soil, whileF. episphaeria was lowest, and rarely found in uncultivated soils.
21 citations
20 citations
16 citations
TL;DR: While nasopharyngeal carcinoma is common in all sections of the immigrant and local-born Chinese population of Singapore, the relative risk is significantly lower for those derived from the Province of Fukien and significantly higher for those belonging to the Cantonese dialect group.
16 citations
TL;DR: The palatal root of the maxillary first permanent molar was found to be most frequently involved, believed to be due to the poor surgical access of this root as well as its close anatomic relationship with the antrum.
TL;DR: There is an inverse relationship between the hepatic activities of the pyrophosphatase and glucuronyltransferase in four species of animals and the reduction in the rate of transglucuronidation by the interfering pyroph phosphatase was most significant in rat liver homogenate.
TL;DR: The case of a Malay infant with natal canine and molar teeth has been presented, and the gross and microscopic features of these teeth have been described.
TL;DR: The results show a significantly higher risk of liver cancer among immigrant Chinese than among the local-born, however, the higher relative risk among China-born Chinese in this study was much less than found previously in surveys of Liver cancer cases necropsied in Singapore between 1950 and 1959.
TL;DR: An aqueous extract of the coral reef crab, Lophozozymus pictor was lethal when injected into mice and had little effect on the response of the gastrocnemius muscle to sciatic nerve stimulation.
TL;DR: Harmol glucuronide synthesized in vitro using uridine diphosphate glucuronic acid and guinea pig liver microsomes was used as a substrate in the measurement of β-glucuronidase present in liver, kidney, spleen, heart, brain, and serum of a number of experimental animals and in human serum.
TL;DR: 10 cases of an S-MDH variant have been detected in New Guinea and the new variant has been given the trivial name S- MDH “New Guinea-1”.
Abstract: 10 cases of an S-MDH variant have been detected in New Guinea. 3 cases were found among 199 samples from the Fore linguistic group and 6 cases among 9 related members of a family from the Agarabi linguistic group, both groups being located in the Eastern Highlands. 1 case was found in 24 samples from the Sepik district. The new variant has been given the trivial name S-MDH “New Guinea-1”.
TL;DR: In this paper, the authors argue that virtual worlds can be viewed as sites of convergence for children's play in that virtual world allow for almost all aspects of children’s play to converge, primarily manifested in the convergence of social spheres and play spaces and playthings.
Abstract: Virtual worlds have made notable inroads into the lives of children, affording online extensions of their offline lives In this article, we propose a conceptual framework for understanding the space that virtual worlds occupy in children’s play and the ways in which children’s participation in them overlap with their everyday play experiences, both offline and mediated. We argue that virtual worlds can be viewed as sites of convergence for children’s play in that virtual worlds allow for almost all aspects of children’s play to converge, primarily manifested in the convergence of social spheres, the convergence of play spaces and playthings, the convergence of cultures and the convergence of learning experiences. we explain how such convergence, while presenting valuable opportunities for children to learn and develop, will not be fully exploited without a corresponding ability on the part of parents and children to recognise potential risks; and for parents and educators to scaffold these learning opportunities.
TL;DR: It would appear that A. caninum absorbs glucose mainly through its intestine, as radioactivity was confined to the tissues of the intestines, whereas radio-activity was not detectable in sections of collared worms even after 5 hours incubation.
TL;DR: This article argued that the needs of a society are not given, but are functions of an already developed culture, and for this reason they cannot be thought of as constants variably filled with diverse cultural content.
Abstract: Attempts to display the underlying similarities of superficially different cultures in terms of basic needs, problems, drives, etc., fail, not, as is usually argued, because of paucity of basic materials relative to superstructure, but rather because of a logical feature of the concepts of need, problem, etc. Societies certainly have needs and problems, which they satisfy and solve, but these already presuppose the existence of a society that constantly subjects its environmental and biological endowment to re-evaluation. The needs of a society are not “given,” therefore, but are functions of an already developed culture, and for this reason they cannot be thought of as constants variably filled with diverse cultural content. [methodology, cultural relativism, needs (basic), meta-anthropology, semantics]
01 Jan 1970
TL;DR: Five species of the family Mononchidae from a single locality in Singapore are described and two are new species, which resembles H. andamanicus but differs in the position of the vulva, the length of the tail and the absence of a post-vulvar uterine sac.
Abstract: Five species of the family Mononchidae from a single locality in Singapore are described. Two are new species. Hadronchus yuenae n. sp. resembles H. andamanicus but differs in the position of the vulva, the length of the tail and the absence of a post-vulvar uterine sac. lotonchus microdontus n. sp. resembles I. acuticaudus and 1. chantaburensis but differs from the former in body length, tail shape, and vulval position, and from the latter in details of the tail terminus and buccal cavity measurements. I. basidontus, I. trichurus, and Mylonchulus curvicaudus were also found and differences from the original descriptions are discussed.
TL;DR: Chez leBalantidium coli, la vacuole contractile se remplit graduellement et s'agrandit en apparence, pendant laquelle elle se gonfle entièrement, devient sphérique, et puis s'affaisse subitement and expulse son contenu.
Abstract: Chez leBalantidium coli, la vacuole contractile se remplit graduellement et s'agrandit. Apres une phase stationnaire, pendant laquelle elle reste irreguliere en apparence, elle se gonfle entierement, devient spherique, et puis s'affaisse subitement et expulse son contenu. L'affaissement est tres rapide et ne prend qu'une fraction de seconde. Le cycle entier dure generallement 20 a 25 secondes.
TL;DR: In this article, the non-vanishing value of the Fermi nuclear matrix element M F is attributed to charge-dependent effects and a value in fair agreement with that obtained experimentally.
01 Jan 1970
TL;DR: The issue of Charters containing legal provisions to the great trading companies was the primary means of establishing the common law in the various colonies from the seventeenth to the mid-nineteenth centuries.
Abstract: The issue of Charters containing legal provisions to the great trading companies was the primary means of establishing the common law in the various colonies from the seventeenth to the mid-nineteenth centuries. As well as containing a statement of that portion of the common law felt suitable for “export” at that time, the background of the Charters also illustrates one of the most peculiar relationships in English legal history: that which existed between the Crown and the East India Company. It is the nature of this relationship which is the subject of this essay.
TL;DR: Silver impregnation and histochemical techniques utilized to study sensory nerve terminations in oral mucous membrane showed heavy concentrations of nerve endings at the anterior part of hard palate, junction between hard and soft palates, papillae of tongue and the transitional zone of lip.