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Institution

University of Malaya

EducationKuala Lumpur, Malaysia
About: University of Malaya is a education organization based out in Kuala Lumpur, Malaysia. It is known for research contribution in the topics: Population & Fiber laser. The organization has 25087 authors who have published 51491 publications receiving 1036791 citations. The organization is also known as: UM & Universiti Malaya.


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Journal ArticleDOI
TL;DR: There is a pronounced annual cyclical variation in the intensity of breeding, with a marked heavy season around June, July, and August, and the existence of a definite peak breeding season is thought to relate to the adaptive advantage of a habit of synchronous breeding aggregation in a widely ranging species.
Abstract: SUMMARY A four-year study was conducted on breeding populations of Green Sea Turtles, Chelonia mydas (Linn.), in Malaya and Sarawak. The area of study was confined to the South China Sea (Sunda Shelf) coasts of the two countries. The history of the exploitation of sea turtle populations for eggs in the Muslim areas of Malaysia is reviewed; compared with other parts of the world where turtles are killed for flesh and fat, the populations in Malaya and Sarawak appear to have suffered little reduction in size. The general aspects of the marine environment and the different types of sea turtle breeding beaches in the area are described. Chelonia mydas tends to build up large breeding concentrations around a small number of beaches, with only limited use of other beaches in the region. Possible causes and adaptive features of the observed situation are discussed. The type of beach utilised by large breeding concentrations of Green Turtles is described, and several particular beaches are described in detail. The process of nesting is described at length, drawing on extensive field notes made over a four-year period. Particular attention is paid to behavioural aspects of the nesting process and to their possible adaptive significance. Female turtles approaching the beach for nesting are very shy while still in the water and still able to make a rapid escape; they show a clear set of reactions to visual stimuli. With progression up onto the land and isolation from the aquatic environment, the turtles show progressively less response to alarm stimuli. Ihe mechanics of terrestrial locomotion and of the various nesting activities are described, along with discussions of inhibitory and initiatory stimuli which appear to govern the different stages in the process. A table is presented showing the timing of the nesting process in three selected observations on individual females. Courtship and copulation in Chelonia mydas are described as they were observed in Malaya and Sarawak. 2,720 adult female turtles were tagged on three islands off Sarawak, where the Sarawak Government operates a turtle egg industry. Through the cooperation of the industry, statistical studies were carried out. Methods of tagging are described and pertinent features of the statistical work are discussed The recorded annual egg production from the three islands averages slightly less than two million eggs a year, with a recorded minimum of 700,000 and a maximum in excess of three million eggs. While there is no non-breeding season in Sarawak, there is a pronounced annual cyclical variation in the intensity of breeding, with a marked heavy season around June, July, and August. The absence of a non-breeding season is considered to be related to the virtual lack of any marked annual variation in temperature. The existence of a definite peak breeding season is thought to relate to the adaptive advantage of a habit of synchronous breeding aggregation in a widely ranging species. The timing of the peak breeding season appears to relate to the period of the Northeast Monsoon, which brings relatively inclement weather from November through February. The development and decline of the breeding season as shown by egg production figures from the industry shows a remarkable consistency through “good” years and “bad”. While presumably located in time to occur when monsoon effects are minimal, it does not show correspondence to yearly fluctuations in the timing of the monsoon. The per cent contribution of each calendar month to the annual total egg production tends to remain constant regardless of whether the monsoon periods preceding or following are early or late. Individual tagged turtles returned repeatedly to the same beach to nest. Of 5,748 records of returning tagged females only 3–7 per cent failed to return to the same island previously used, despite the fact that two of the islands were only about 500 metres apart. Female turtles nested six or seven times in a season at intervals of about 10 days. Records showed a maximum of 11 successful nests made by a single individual. 8,147 clutches of eggs averaged 104-7 eggs per clutch, with a Standard Deviation of 1–31. The return in 1956 of numbers of the turtles tagged in 1953 indicates a three-year breeding cycle in the Sarawak turtles, and provides evidence that individuals are able to make their way back to the same nesting grounds after the long absence. The environment of the incubating nest is described and the hatchery procedures practised on the Sarawak islands are outlined. A special series of nests was transplanted to the industry's hatchery enclosure for studies on incubation. Although surface sand temperatures underwent a diurnal fluctuation of as much as 23o C, at the depths where eggs were deposited the measured temperature never fluctuated more than about 2o C. Incubating nests showed a progressive temperature rise due to the metabolic heat produced by the developing embryos, reaching temperatures as high as 35o C. by the time of hatching. Records of 354 hatchery nests showed an average of 47 per cent of the transplanted eggs resulting in hatchlings which emerged to the surface. Recorded intervals between oviposition and time of emergence of young turtles to the surface varied seasonally from an average of about 70 days during the latter part of February to an average of about 54 days during the period June to October. The process of emergence of the hatchling turtles from their subterranean chamber and their movement to the sea is described. The available data on growth rate and age of maturation is assembled and discussed. It is concluded that Asian Green Turtles probably mature in from four to six years. The carapace measurements of 200 adult females from Sarawak are plotted on a graph; the weights and carapace measurements of ten females are given in a table. Predation upon incubating nests and upon turtles at all stages is discussed. Ghost Crabs (Ocypoda sp.) were the most serious observed menace to incubating nests in the areas studied. The heaviest predation observed on hatchling turtles was by Ghost Crabs and small sharks. There is little predation by sea birds on the Malaysian beaches. Several large Tiger Sharks (Galeocerdo sp.) were caught off the Sarawak islands; two of these had the remains of adult sea turtles in their stomachs. The various parasites and commensals found on turtles during the study are reported; observations are made on the burrowing parasitic barnacle, Stephanolepas muricata, and its apparent tumour-inducing proclivities. The paper concludes with an analysis of the problem of scientific management of wild populations of Green Turtles. It is concluded that exploitation for eggs is more logical, more profitable, and more amenable to management techniques than is exploitation for flesh and fat.

231 citations

Journal ArticleDOI
TL;DR: Dengue has extended to different tropical areas and older age groups and Variations from the original description of dengue manifestations are being reported.
Abstract: Summary Background The current World Health Organisation (WHO) classification of dengue includes two distinct entities: dengue fever (DF) and dengue haemorrhagic fever (DHF)/dengue shock syndrome; it is largely based on pediatric cases in Southeast Asia. Dengue has extended to different tropical areas and older age groups. Variations from the original description of dengue manifestations are being reported. Objectives To analyse the experience of clinicians in using the dengue case classification and identify challenges in applying the criteria in routine clinical practice. Method Systematic literature review of post-1975 English-language publications on dengue classification. Results Thirty-seven papers were reviewed. Several studies had strictly applied all four WHO criteria in DHF cases; however, most clinicians reported difficulties in meeting all four criteria and used a modified classification. The positive tourniquet test representing the minimum requirement of a haemorrhagic manifestation did not distinguish between DHF and DF. In cases of DHF thrombocytopenia was observed in 8.6–96%, plasma leakage in 6–95% and haemorrhagic manifestations in 22–93%. The low sensitivity of classifying DHF could be due to failure to repeat the tests or physical examinations at the appropriate time, early intravenous fluid therapy, and lack of adequate resources in an epidemic situation and perhaps a considerable overlap of clinical manifestations in the different dengue entities. Conclusion A prospective multi-centre study across dengue endemic regions, age groups and the health care system is required which describes the clinical presentation of dengue including simple laboratory parameters in order to review and if necessary modify the current dengue classification. Donnees de base La classification actuelle de l'organisation Mondiale de la Sante (OMS) pour la dengue comprends deux entites: la fievre dengue et la fievre hemorragique dengue/syndrome de choque dengue; elle est largement basee sur des cas pediatriques du sud-est asiatique. La dengue s'est pourtant etendue a differentes zones tropicales et a des groupes plus âges. Des variations a la description originale des manifestations de la dengue sont couramment rapportees. Objectifs Analyser les experiences des cliniciens dans la classification des cas de dengue et identifier les defis dans l'application des criteres en pratique clinique de routine Methodes Revue systematique des publications anglaises depuis 1975 sur la classification de la dengue Resultats 37 articles ont ete revus. Plusieurs etudes ont strictement applique tous les 4 criteres de l'OMS dans les cas de fievre hemorragique dengue. Cependant, la plupart des cliniciens ont rapporte des difficultes a rassembler tous les 4 criteres et ont alors utilise une classification modifiee. Le test positif du tourniquet representant le minimum requis pour une manifestation hemorragique ne distinguait pas entre fievre hemorragique dengue et fievre dengue. Dans les cas de fievre hemorragique dengue, de la thrombocytopenie etait observee chez 8,6 a 96% des cas, de l’ecoulement de plasma chez 6 a 95% des cas et des manifestations hemorragiques chez 22 a 93% des cas. La faible sensibilite de la classification de la fievre hemorragique de la dengue pourrait etre due au manque de repetition des tests ou d'examens physiques a des moments appropries, a l'instauration tres tot d'un traitement intraveineux des fluides et au manque de ressources adequates dans les situations d’epidemie et peut etre aussi a une superposition des manifestations cliniques dans differentes entites de dengue. Conclusion Une etude multi centre prospective dans les regions endemiques de la dengue sur les groupes d’âge et le systeme des soins de sante est necessaire pour decrire les presentations cliniques de la dengue incluant de simples parametres de laboratoire afin de corriger et si necessaire de modifier la classification actuelle de la dengue. Antecedentes La clasificacion actual de la Organizacion Mundial de la Salud (OMS) para el dengue incluye dos entidades diferentes: la fiebre del dengue (FD) y la fiebre hemorragica del dengue (FHD)/sindrome de shock por dengue (SSD). Esta clasificacion esta principalmente basada en casos pediatricos del sureste asiatico. El dengue se ha extendido a diferentes areas tropicales y a grupos con mayor edad. Las variaciones de la descripcion original de las manifestaciones del dengue se reportan en este articulo. Objetivos Analizar la experiencia de los clinicos en el uso de la clasificacion del caso de dengue e identificar los retos en aplicar los criterios en una practica clinica de rutina. Metodo Revision sistematica de publicaciones en ingles desde 1975 que tratasen el tema de la clasificacion del dengue. Resultados Se revisaron 37 publicaciones. Algunos estudios aplicaban estrictamente los cuatro criterios de la OMS en casos de FHD; sin embargo, la mayoria de los clinicos reportaron dificultades para cumplir los cuatro criterios y utilizaron una clasificacion modificada. El test positivo del torniquete, que representa el requerimiento minimo para la manifestacion hemorragica no distinguio entre FHD y SSD. En los casos de FHD se observo trombocitopenia en un rango de 8.6% a 96%, fuga de plasma en 6% a 95% y manifestaciones hemorragicas en 22% a 93%. La baja sensibilidad en la clasificacion de FHD podria deberse a un fallo en la repeticion de las pruebas o examenes fisicos en el momento apropiado, a una terapia temprana de fluidos intravenosos y falta de recursos adecuados en una situacion epidemica y tal vez a un solapamiento considerable de manifestaciones clinicas en las diferentes entidades del dengue. Conclusion Se requiere un estudio prospectivo, multicentrico que incluya todas las regiones endemicas para dengue, grupos de edad y sistemas sanitarios, que describa la presentacion clinica del dengue incluyendo parametros de laboratorio simples, con el fin de revisar y si fuese necesario modificar la clasificacion actual del dengue.

231 citations

Journal ArticleDOI
TL;DR: This review summarizes the current status of knowledge of the peripheral and central sources of insulin in the brain, site-specific expression of IRs, and also neurophysiological functions of insulin including the regulation of food intake, weight control, reproduction, and cognition and memory formation and considers the neuromodulatory and neurotrophic effects of insulin.
Abstract: Historically, insulin is best known for its role in peripheral glucose homeostasis, and insulin signaling in the brain has received less attention. Insulin-independent brain glucose uptake has been the main reason for considering the brain as an insulin-insensitive organ. However, recent findings showing a high concentration of insulin in brain extracts, and expression of insulin receptors (IRs) in central nervous system tissues have gathered considerable attention over the sources, localization, and functions of insulin in the brain. This review summarizes the current status of knowledge of the peripheral and central sources of insulin in the brain, site-specific expression of IRs, and also neurophysiological functions of insulin including the regulation of food intake, weight control, reproduction, and cognition and memory formation. This review also considers the neuromodulatory and neurotrophic effects of insulin, resulting in proliferation, differentiation, and neurite outgrowth, introducing insulin as an attractive tool for neuroprotection against apoptosis, oxidative stress, beta amyloid toxicity, and brain ischemia.

230 citations

Journal ArticleDOI
TL;DR: These are the first direct limits for N mass above 500 GeV and the first limits obtained at a hadron collider for N masses below 40 Ge V.
Abstract: A search for a heavy neutral lepton N of Majorana nature decaying into a W boson and a charged lepton is performed using the CMS detector at the LHC. The targeted signature consists of three prompt charged leptons in any flavor combination of electrons and muons. The data were collected in proton-proton collisions at a center-of-mass energy of 13 TeV, with an integrated luminosity of 35.9 fb^(−1). The search is performed in the N mass range between 1 GeV and 1.2 TeV. The data are found to be consistent with the expected standard model background. Upper limits are set on the values of |V_(eN)|^2and |V_(μN)|^2, where V_(lN) is the matrix element describing the mixing of N with the standard model neutrino of flavor l. These are the first direct limits for N masses above 500 GeV and the first limits obtained at a hadron collider for N masses below 40 GeV.

230 citations

Journal ArticleDOI
TL;DR: In this article, the authors present a review of the LCA methods and to distinguish phases and materials that affect significantly to environment, and the findings show the methods are based on ISO 14040 series with variance to suit different scopes, aims and limitations.
Abstract: A recent study suggested that buildings globally consume up to 40% of energy and responsible for half of world greenhouse gas emission. Introducing life cycle assessment (LCA) to the building industry is important because it can measure every environmental impact involved in every process from cradle to grave systematically. Within the last decade, research on LCA has increased covering from construction process to manufacturing of building materials. The methods to assess buildings are diverse as buildings have different functions, materials, sizes and locations. The aim of this article is to review the LCA methods and to distinguish phases and materials that affect significantly to environment. The findings show the methods are based on ISO 14040 series with variance to suit different scopes, aims and limitations. The operational phase is identified to consume the highest energy and concrete responsible for the highest embodied energy. The findings also suggested that building material with lower embodied energy does not necessarily have lower life cycle energy. Therefore, implementation of LCA can determine and mitigate the environmental impacts in the development stage thus promoting sustainability in building industry.

230 citations


Authors

Showing all 25327 results

NameH-indexPapersCitations
Diederick E. Grobbee1551051122748
Intae Yu134137289870
Ovsat Abdinov12986478489
Jyothsna Rani Komaragiri129109782258
Odette Benary12884474238
Paul M. Vanhoutte12786862177
Irene Vichou12676272520
Ian O. Ellis126105175435
Louisa Degenhardt126798139683
Matthew Jones125116196909
Andrius Juodagalvis118106967138
Martin Ravallion11557055380
R. St. Denis11292165326
Xiao-Ming Chen10859642229
A. Yurkewicz10651451537
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202391
2022418
20213,698
20203,646
20193,239
20183,203