Showing papers by "University of Malaya published in 1970"
99 citations
TL;DR: Several theorems giving necessary and sufficient conditions for v directed graph to be a network graph are obtains, and the results are applied to solving some problems of smoothing traffic flow.
Abstract: Let G be a directed graph such that even edge e of G is associated with a positive integer, called the index of e. Then G is called a network graph if, at every vertex v of G, the sum of the indices of the edges terminating at v is equal to that of the edges incident from v. This paper obtains several theorems giving necessary and sufficient conditions for v directed graph to be a network graph, and applies the results to solving some problems of smoothing traffic flow.
38 citations
TL;DR: Evidence is presented that each species of bat actively selected roosts of a different range of dimensions and the ecological implications of the separation of the species by this factor are discussed.
Abstract: During six years, 1962–68, the biology of the bats Tylonycteris pachypus and T. robustula has been studied at the University of malaya Field Studies Centre, Ulu Gombak, Selangor, Malaysia. Both species were often found roosting within internodes of the bamboo Gigantochloa scortechinii, entering and leaving through narrow vertical slits caused by the beetle Lasiochila goryi. In this paper the roost sites are described and evidence is presented that each species of bat actively selected roosts of a different range of dimensions. The ecological implications of the separation of the species by this factor are discussed.
34 citations
01 Sep 1970-Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology
TL;DR: Since the phylogenetic step from the progeotaxis to the metageotaxis coincides with the incorporation of the photo-geotactic transfer of angles into the dance language of the honey bees, it seems probable that metagotaxis has a special biological significance for the geotactic communication of direction by dancing bees.
Abstract: 1.
Innerhalb der Uberfamilie der Bienen (Apoidea) gibt es zwei Typen der Geotaxis: Bei der laufenden Biene mit Progeotaxis verkleinert sich der Orientierungswinkel zur Schwerkraft mit zunehmendem Neigungswinkel der Unterlage, wogegen er bei Bienen mit Metageotaxis konstant bleibt.
2.
Die Trennlinie fur die Verbreitung dieser beiden Geotaxistypen liegt innerhalb der Gattung Apis: A. dorsata, A. cerana und A. mellifica verfugen uber eine Metageotaxis; A. florea so wie alle ubrigen, hier untersuchten Bienen reagieren unter den gleichen Versuchsbedingungen mit einer Progeotaxis.
3.
Da der phylogenetische Schritt von der Progeotaxis zur Metageotaxis mit dem Einbau des photo-geotaktischen Winkeltransponierens in den Bienentanz zusammenfallt, kann es als wahrscheinlich gelten, das die Evolution zur Metageotaxis von besonderer biologischer Bedeutung fur die geotaktisch orientierte Richtungsanzeige in der Tanzsprache der Honigbiene ist.
28 citations
TL;DR: In this article, the shape of the blades was found to be an important factor greatly affecting rotary tillage of wet (supersaturated) soils by power-driven soil-engaging blades.
27 citations
TL;DR: A mutation (ff-1) which specifically destroys the ability to develop protoperithecia was found in Neurospora crassa and causes no change in vegetative morphology.
Abstract: A mutation (ff-1) which specifically destroys the ability to develop protoperithecia was found in Neurospora crassa. This mutation causes no change in vegetative morphology. It is located between arg-5 and try-3 on the right arm of linkage group II.
26 citations
TL;DR: Germination of the spores of bracken fern was accompanied by hydrolysis of storage proteins and increased accumulation of RNA, which suggests possible mechanism involving the existence of preformed messengers in the dormant spore which provide templates for the first proteins of germination.
23 citations
TL;DR: It was concluded that the electrode method of measuring ionized calcium is probably the simplest and most practicable method for determining ionic calcium in human serum.
22 citations
18 citations
TL;DR: In this paper, the authors used a tropical rice strain and showed that multipass drying of wet paddy (with limited moisture content removal per pass, and a period of tempering between each pass) greatly improves milling head yields.
17 citations
TL;DR: In Malesia most species of Lithocarpus may be distinguished from those of Castanopsis by the ridged inner surface of their bark, uniseriate and multiseriate wood-rays, spiral arrangement of leaves and bud-scales, and by their cupule which always encloses one fruit only.
Abstract: Lithocarpus Bl. (1826) is here considered to include the following genera: Synaedrys Lindl. (1836), Cyclobalanus (Endl.) Oersted (1867, p.p.),and Pasania (Miq.) Oersted (1867, p.p.).In Malesia 104 species are recognized, of which 25 are new to science and 7 are new combinations.Apart from these there are 10 more species which are considered as doubtful,as from the specimens so far examined it is difficult to decide their correct status. Pasania littoralis (Bl.) Oersted (basionym: Quercus littoralis Bl.)is excluded from the genus, and the species has been reidentified by Dr. A.J.G.H.Kostermans (Bogor) as Atuna scabra (Hassk.)Kosterm.In Malesia most species of Lithocarpus may be distinguished from those of Castanopsis by the ridged inner surface of their bark, uniseriate and multiseriate wood-rays,spiral arrangement of leaves and bud-scales,and by their cupule which always encloses one fruit only, and which are solitary or in dichasial clusters along the rachis, possessing interseminal cupule segments and a scattered pattern of vascularization.
TL;DR: Examination of the stomach contents of 93 Bufo asper from Templer Park and Batu Caves, Selangor, Malaysia, shows that it feeds upon a wide range of invertebrates.
TL;DR: Bony lesions caused by Cryptococcus neoformans in the absence of a disseminated disease are uncommon, and a case of a solitary osseous lesion is recorded.
Abstract: Bony lesions caused by Cryptococcus neoformans in the absence of a disseminated disease are uncommon. A case of a solitary osseous lesion is recorded, and a review of skeletal involvement in cryptococcosis is discussed.
TL;DR: Karyotype and serological studies provide conclusive evidence for the distinctness as well as the close affinity of these two species.
TL;DR: Apples loaded with spores early in the season rotted later than similar apples loaded just before picking, and polygalacturonase was detected in sap expressed from rotted apples of various ages, the level of activity being correlated with the susceptibility of the fruit.
Abstract: SUMMARY
In N. Ireland Diaporthe perniciosa March is a common inhabitant of the dead wood of Bramley's Seedling apple trees, and its pycnospores, extruded throughout the growing season, are responsible for fruit infections which result in stalk-end rots during storage.
Pycnidia were produced in culture only after exposure to light, near-UV radiation being particularly favourable. The carbon source in the medium influenced pycnidia production: high yields were obtained where mannitol was used. Only a-spores germinated under the conditions tested, giving optimum germination at 25 dC. in a water film. No germination occurred at less than 98% R.H. Germ tubes and hyphae developed appressoria after germination on artificial surfaces but on apple skin most spores produced only a protuberance from which penetration hyphae developed directly. The cuticle and epidermal cells of apples of all ages were penetrated within a few days of inoculation. Intact surfaces and lenticels were penetrated equally. Susceptibility to further rotting increased with age of the fruit. Apples loaded with spores early in the season rotted later than similar apples loaded just before picking. Polygalacturonase was detected in sap expressed from rotted apples of various ages, the level of activity being correlated with the susceptibility of the fruit.
TL;DR: Using a newly developed calcium-sensitive electrode, the effect of glucagon on the plasma ionic calcium in monkeys was investigated and it was observed that the hormone causes a significant depression of both the total and ionsic calcium levels.
Abstract: Using a newly developed calcium-sensitive electrode, the effect of glucagon on the plasma ionic calcium in monkeys was investigated. It was observed that the hormone causes a significant depression of both the total and ionic calcium levels.
TL;DR: The number of spores of each isolate required to initiate infection in half the leaves (the ED50) was determined by inoculating leaflets with a range of spore concentrations and subjecting the data to probit analysis as mentioned in this paper.
Abstract: Twenty-seven isolates of Colletotrichum gloeosporioides from Hevea brasiliensis differed greatly in appearance, in intensity of sporulation, in the effect on sporulation of exposure to light and the addition of L -asparagine to the medium, and in pathogenicity to young leaves of Hevea . The number of spores of each isolate required to initiate infection in half the leaflets (the ED50) was determined by inoculating leaflets with a range of spore concentrations and subjecting the data to probit analysis. Comparison of ED50 values on leaves of different ages indicated that susceptibility to infection decreased with age, with a well-defined increase in resistance between the eleventh and thirteenth day of leaf development. This coincided with the formation of the cuticle.
TL;DR: In this paper, the stability of C6H5CHXZnX, studied by iodometric titration, was shown to decrease in the order: X = I > Br > Cl.
TL;DR: In this paper, the effect of aromatic and non-aromatic solvents on the proton chemical shifts of 23 polar compounds has been determined based on evidence provided by infrared data, the highfield shifts of the acidic protons in benzene solution are interpreted in terms of a model involving CHπ hydrogen bonding.
Abstract: The effect of aromatic and non-aromatic solvents on the proton chemical shifts of 23 polar compounds has been determined. The protons which are activated by electron-withdrawing groups show large highfield shifts in benzene (relative to the isotropic solvents). Based on evidence provided by infrared data, the highfield shifts of the acidic protons in benzene solution are interpreted in terms of a model involving CHπ hydrogen bonding. This model successfully interprets the data reported previously for steroidal ketones. The same model can be extended to benzene solutions of other polar compounds containing strongly electron-deficient sites to which alkyl groups are attached. It is observed that the use of CCl4 as a reference solvent in studies of benzene induced shifts may have greater significance, since these two solvents have similar dielectric constants.
TL;DR: In this paper, the relative rates of radical chlorination of m- and p- substituted benzaldehydes with sulphuryl chloride at 40° in CCl4 have been determined by means of a competitive reaction using p-diethylbenzene as reference standard.
TL;DR: In this paper, the relative rates of chlorination of substituted benzaldehydes with CCl 3 SO 2 Cl (I) have been determined in dilute CCl 4 solution at 80° by means of competitive reactions using p -diethylbenzene as reference standard.
TL;DR: Three hundred and sixty‐six patients with a history of previous Caesarean section or hysterotomy have been studied with reference to subsequent labour and mode of delivery in 454 pregnancies.
Abstract: Three hundred and sixty‐six patients with a history of previous Caesarean section or hysterotomy have been studied with reference to subsequent labour and mode of delivery in 454 pregnancies. Elective Caesarean section was performed in 132 (29%); vaginal delivery, which was attempted in 322 cases, was successful in 78%. The vaginal delivery rate for the whole series was 55%. The type of uterine scar and state of scar at subsequent delivery are recorded. The incidence of scar dehiscence was found to be 1.1%. There was no maternal mortality in the series but an increase was noted in maternal morbidity. Copyright © 1970, Wiley Blackwell. All rights reserved
TL;DR: In this paper, a SH2 mechanism involving initial attack of tri-n-butyltin radical at the ethereal oxygen atom of the ester with displacement of the benzoyl moiety appears to be consistent with observed experimental evidence.