Displaying publications 741 - 760 of 4601 in total

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  1. Spectacular Batesian mimicry in ants
    Ito F, Hashim R, Huei YS, Kaufmann E, Akino T, Billen J
    Naturwissenschaften, 2004 Oct;91(10):481-4.
    PMID: 15729761
    The mechanism by which palatable species take advantage of their similarity in appearance to those that are unpalatable, in order to avoid predation, is called Batesian mimicry. Several arthropods are thought to be Batesian mimics of social insects; however, social insects that are Batesian mimics among themselves are rare. In Malaysia we found a possible Batesian mimic in an arboreal ant species, Camponotus sp., which was exclusively observed on foraging trails of the myrmicine ant Crematogaster inflata. The bright yellow and black colouring pattern, as well as the walking behaviour, were very similar in both species. We observed general interactions between the two species, and tested their palatability and the significance of the remarkably similar visual colour patterns for predator avoidance. Prey offered to C. inflata was also eaten by Camponotus workers in spite of their being attacked by C. inflata, indicating that Camponotus sp. is a commensal of C. inflata. An experiment with chicks as potential predators suggests that Camponotus sp. is palatable whereas C. inflata is unpalatable. After tasting C. inflata, the chicks no longer attacked Camponotus sp., indicating that Camponotus sp. is a Batesian mimic of Crematogaster inflata.
    Matched MeSH terms: Ants/physiology*
  2. Physical Activity Measurement by Accelerometry Among Older Malay Adults Living in Semi-Rural Areas-A Feasibility Study
    Zainol Abidin N, Brown WJ, Clark B, Muhamed AM, Singh R
    J Aging Phys Act, 2016 10;24(4):533-539.
    PMID: 26964887
    We evaluated feasibility of physical activity measurement by accelerometry among older Malay adults living in semi-rural areas in Malaysia. Results showed that 95% of 146 participants (aged [SD] 67.6 [6.4] years) were compliant in wearing the accelerometer for at least five days. Fifteen participants were asked for re-wear the accelerometer because they did not have enough valid days during the first assessment. Participants wore the accelerometer an average of 15.3 hr in a 24-hr day, with 6.5 (1.2) valid wear days. No significant difference in valid wear day and time was found between men and women. Participants who are single provide more valid wear days compared with married participants (p < .05), and participants with higher levels of education provide longer periods of accelerometer wearing hours (p < .01). Eighty-seven percent of participants reported 'no issues' with wearing the meter. This study suggests that accelerometry is a feasible method to assess the physical activity level among older Malay adults living in semi-rural areas.
    Matched MeSH terms: Exercise/physiology*
  3. Handedness, sexual orientation, and somatic markers for prenatal androgens: Are southpaws really that gay?
    Ellis L, Skorska MN, Bogaert AF
    Laterality, 2017 Mar;22(2):157-180.
    PMID: 26932806 DOI: 10.1080/1357650X.2016.1151024
    BACKGROUND: Some evidence suggests that prenatal androgens influence both handedness and sexual orientation. This study sought to clarify how androgens, handedness, and sexual orientation are interrelated.

    METHODS: Data were obtained from large samples of students enrolled at universities in Malaysia and the US, including self-reported information on handedness, sexual orientation, and five somatic markers of prenatal androgen exposure (2D:4D, height, strength, muscularity, and athletic ability). Factor analysis of these somatic markers yielded two factors: a muscular coordination and a bone growth factor.

    RESULTS: In women, but not in men, ambidextrousness was more prevalent among those with homosexual tendencies. Modest and often complex associations were found between the androgen factors and handedness. Clear links between the androgen factors and sexual orientation were found, especially for muscular coordination. For males and females, intermediate sex-typical androgen exposure was associated with heterosexual preferences.

    CONCLUSIONS: Ambidextrousness appears to be somewhat more common among females with homosexual tendencies, but left-handedness is nearly as strongly associated with heterosexual preferences, particularly in males, as is right-handedness. Factors indicative of prenatal androgen exposure are associated with sexual orientation in theoretically predictable ways, especially for muscular coordination, but associations between prenatal androgens and handedness are complex.

    Matched MeSH terms: Body Height/physiology; Fingers/physiology; Homosexuality/physiology*; Functional Laterality/physiology*; Motor Skills/physiology; Heterosexuality/physiology*; Muscle Strength/physiology
  4. Fulltext Pliable Cognitive MAC for Heterogeneous Adaptive Cognitive Radio Sensor Networks
    Al-Medhwahi M, Hashim F, Ali BM, Sali A
    PLoS One, 2016;11(6):e0156880.
    PMID: 27257964 DOI: 10.1371/journal.pone.0156880
    The rapid expansion of wireless monitoring and surveillance applications in several domains reinforces the trend of exploiting emerging technologies such as the cognitive radio. However, these technologies have to adjust their working concepts to consider the common characteristics of conventional wireless sensor networks (WSNs). The cognitive radio sensor network (CRSN), still an immature technology, has to deal with new networks that might have different types of data, traffic patterns, or quality of service (QoS) requirements. In this paper, we design and model a new cognitive radio-based medium access control (MAC) algorithm dealing with the heterogeneous nature of the developed networks in terms of either the traffic pattern or the required QoS for the node applications. The proposed algorithm decreases the consumed power on several fronts, provides satisfactory levels of latency and spectrum utilization with efficient scheduling, and manages the radio resources for various traffic conditions. An intensive performance evaluation is conducted to study the impact of key parameters such as the channel idle time length, node density, and the number of available channels. The performance evaluation of the proposed algorithm shows a better performance than the comparable protocols. Moreover, the results manifest that the proposed algorithm is suitable for real time monitoring applications.
    Matched MeSH terms: Cognition/physiology*
  5. Past and future of the EU-habitat directive species Liparis loeselii in relation to landscape and habitat dynamics in SW-Texel, the Netherlands
    Kooijman AM, Bruin CJW, van de Craats A, Grootjans AP, Oostermeijer JGB, Scholten R, et al.
    Sci Total Environ, 2016 Oct 15;568:107-117.
    PMID: 27289393 DOI: 10.1016/j.scitotenv.2016.05.086
    Dune slacks are important habitats, with many endangered plant species. A series of eleven dune slacks of 1-42years old was studied in SW-Texel, the Netherlands, with the EU-habitat directive species Liparis loeselii present in all except the youngest and oldest. Analysis of aerial photographs revealed that new slacks are currently formed every 4-5years. In each slack, topsoil and vegetation data were collected in 2010 and 2014-2015. During succession, vegetation changed from brackish pioneer stages to dune slacks with L. loeselii and Parnassia palustris and ultimately grassland species. Differences between dune slacks and sampling periods were mostly significant. Herb cover and soil C increased with slack age, and over the five year study period, while bare sand, bulk density and pH decreased. The annual pH-decrease was 0.055 and 0.075 for pH-H2O and pH-KCl respectively, and annual C-increase 0.16% and 35gm(-2). Liparis loeselii was only present between pHH2O 5.8-7.5 and pHKCl 5.6-7.6, and only occurred at C-content below 4.3%. In lime-poor dunes, environmental conditions thus become unsuitable approximately 34years after the start of succession. In the dune slacks, Liparis loeselii established within 6years, showed peak values after 11-16years, and declined until conditions became unsuitable. Rejuvenation may occur after large storms with fresh sand deposits. However, even with further succession, the present populations are not endangered and probably last until 2040. With new dune slacks every 5years, L. loeselii occurs in approximately eight different dune slacks at the same time, ensuring viable populations also in the future. This shows that adverse effects of succession can be counteracted by dynamics on local and landscape scale.
    Matched MeSH terms: Orchidaceae/physiology*
  6. Review: the Multiple Roles of Monocytic Microparticles
    Halim AT, Ariffin NA, Azlan M
    Inflammation, 2016 Aug;39(4):1277-84.
    PMID: 27216803 DOI: 10.1007/s10753-016-0381-8
    Monocytic microparticles (mMP) are microparticles derived from human monocytes either under in vivo or in vitro conditions. The size of mMP is between 0.1 and 1.0 μm. Apart from the size range, mMPs are also identified based on phosphatidylserine and CD14 expression on their surface, though this is not always the case. Monocytic MP are critical players in inflammation, endothelial cell function, and blood coagulation. They exhibit dual function by either helping the progression of such conditions or limiting it, depending on certain factors. Furthermore, the numbers of mMP are elevated in some autoimmune diseases, infectious diseases, and metabolic disorders. However, it is unknown whether mMP play an active role in these diseases or are simply biomarkers. The mechanism of mMP modulation is yet to be identified. In this review, we highlight the mechanism of mMP formation and the roles that they play in inflammation, blood coagulation, and different disease settings.
    Matched MeSH terms: Cell-Derived Microparticles/physiology*
  7. A new twist on a very old binary similarity coefficient
    Alroy J
    Ecology, 2015 Feb;96(2):575-86.
    PMID: 26240877
    Pairwise similarity coefficients are downward biased when samples only record presences and sampling is partial. A simple but forgotten index proposed by Stephen Forbes in 1907 can help solve this problem. His original equation requires knowing the number of species absent in both samples that could have been present. It is proposed that this count should simply be ignored and that the coefficient should be adjusted using a simple heuristic correction. Four analyses show that the corrected equation outperforms the Dice and Simpson indices, which are highly correlated with many others. In two-sample simulations, similarity is almost always closer to the assumed value when the species pool size and sampling intensity are varied, regardless of whether the underlying abundance distribution is uniform, log-normal, or geometric. The index is also much more robust when sampling is unequal. An analysis of bat samples from peninsular Malaysia buttresses these conclusions. The corrected coefficient also indicates that local assemblages of North American mammals are random subsamples of larger species pools by returning similarity of values of around 1, and it suggests a more consistent relationship between biome-scale comparisons and local-scale comparisons. Finally, it yields a better-dispersed pattern when the biome-scale inventories are ordinated. If these results are generalizable, then the new and old equation should see wide application, potentially taking the place of the two most commonly used alternatives (the interrelated Dice and Jaccard indices) whenever sampling is incomplete.
    Matched MeSH terms: Mammals/physiology*
  8. Is there any difference in using blur as a stimulus for accommodation between emmetropes and myopes?
    Chen AH
    Documenta ophthalmologica. Advances in ophthalmology, 2002 Jul;105(1):33-9.
    PMID: 12152800
    The purpose of this study was to determine if there was any difference between myopes and emmetropes in using blur as a stimulus for accommodation when the chromatic aberration, size and proximal cues were eliminated. Twenty adults (10 myopes and 10 emmetropes) were examined for their accuracy of accommodation response for five different accommodation demands (OD, 1D, 2D, 3D, 4D) under two different light sources: achromatized white light versus monochromatic light. There was no significant difference in using blur stimulus between myopes and emmetropes when the chromatic aberration, size and proximal cues were eliminated.
    Matched MeSH terms: Accommodation, Ocular/physiology*
  9. Asynchronous emergence by loggerhead turtle (Caretta caretta) hatchlings
    Houghton JD, Hays GC
    Naturwissenschaften, 2001 Mar;88(3):133-6.
    PMID: 11402844
    For many decades it has been accepted that marine turtle hatchlings from the same nest generally emerge from the sand together. However, for loggerhead turtles (Caretta caretta) nesting on the Greek Island of Kefalonia, a more asynchronous pattern of emergence has been documented. By placing temperature loggers at the top and bottom of nests laid on Kefalonia during 1998, we examined whether this asynchronous emergence was related to the thermal conditions within nests. Pronounced thermal variation existed not only between, but also within, individual nests. These within-nest temperature differences were related to the patterns of hatchling emergence, with hatchlings from nests displaying large thermal ranges emerging over a longer time-scale than those characterised by more uniform temperatures. In many egg-laying animals, parental care of the offspring may continue while the eggs are incubating and also after they have hatched. Consequently, the importance of the nest site for determining incubation conditions may be reduced since the parents themselves may alter the local environment. By contrast, in marine turtles, parental care ceases once the eggs have been laid and the nest site covered. The positioning of the nest site, in both space and time, may therefore have profound effects for marine turtles by affecting, for example, the survival of the eggs and hatchlings as well as their sex (Janzen and Paukstis 1991). During incubation, sea turtle embryos grow from a few cells at oviposition to a self-sufficient organism at hatching some 50-80 days later (Ackerman 1997). After hatching, the young turtles dig up through the sand and emerge typically en masse at the surface 1-7 nights later, with a number of stragglers following over the next few nights (Christens 1990). This contrasts with the frequently observed pattern of hatching asynchrony in birds. It has been suggested that the cause of mass emergence in turtles is that eggs within a clutch are fertilised within a short period of time and then, when thermal conditions within the nest are uniform, develop at very similar rates and hence hatch and emerge together (Porter 1972). As a corollary of this idea, it would be predicted that when there are pronounced within-nest thermal gradients, development rates of siblings will be different and hence asynchronous hatching and emergence might occur. While it may be energetically beneficial for hatchlings to emerge in a group (Carr and Hirth 1961), if the extent of hatching asynchrony is marked then there may be severe costs for individuals if they wait for all their siblings to hatch before attempting to dig out of the sand (Hays and Speakman 1992). Under such conditions, the protracted emergence of small groups of hatchlings over several nights may be favoured. Examination of the literature suggests that emergence asynchrony may be more widespread than generally considered. For example, Witherington et al. (1990) described loggerhead turtle hatchlings (Caretta caretta) emerging over 4 days in Florida; for green turtles (Chelonia mydas), Hendrickson (1958) documented that nests in Malaysia and Sarawak produced hatchlings for up to 8 days; whilst Diamond (1976) found that hawksbill (Eretmochelys imbricata) nests on Cousin Island, Seychelles, were active for up to 4 days. Similarly, on the Greek Island of Kefalonia, we have shown that emergence from individual loggerhead turtle nests may occur on up to 11 nights (Hays and Speakman 1992). It is logical to suppose that asynchronous emergence relates to thermal gradients within nests, since the incubation duration of sea turtle eggs is related to temperature, with eggs hatching quicker when the temperature is higher. Here we test this hypothesis by measuring thermal variations within loggerhead turtle nests and comparing these variations to the patterns of hatchling emergence.
    Matched MeSH terms: Turtles/physiology*
  10. Mating system parameters of Dryobalanops aromatica Gaertn. f. (Dipterocarpaceae) in three different forest types and a seed orchard
    Lee SL
    Heredity (Edinb), 2000 Oct;85 Pt 4:338-45.
    PMID: 11122411
    The mating system of Dryobalanops aromatica in three different forest types and a seed orchard was quantified by allozyme analysis of progeny arrays using a mixed-mating model. The primary forest (Bukit Sai) had the highest multilocus outcrossing rate (tm=0.923 +/- 0.035), followed by logged forest (Lesong; tm=0.766 +/- 0.056) and artificial forest (FRIM; tm=0.661 +/- 0.066) with seed orchard showing the lowest (Tampin; tm=0.551 +/- 0.095). Deviations from the mixed mating model were evident from differences in pollen and ovule allele frequencies, and heterogeneity of pollen pools in all three different forest types and the seed orchard. A high rate of outcrossing in primary forest (tm=0.92) may indicate that the species is self-incompatible, but a lower value in the seed orchard (tm=0.55) might suggest further that the self-incompatibility system is weak. The outcrossing rate was greater in the primary forest (tm=0.92) than in logged forest (tm=0.77). It is argued that this might be a consequence of the lower density of flowering trees and alteration of pollinator foraging behaviour in logged forest. Higher values of correlated mating (rp) and biparental mating (tm - ts) in primary forest (0.08 and 0.39, respectively) in comparison with logged forest (0.03 and 0.11, respectively) demonstrate that logging activities might reduce the seeds produced through consanguineous mating. Compared with primary forest, it is argued that lower rates of outcrossing in artificial forest (tm=0.67) and seed orchard (tm=0. 55) might be attributed to lack of flowering synchrony and insufficient number of pollinators. The high level of correlated mating (rp=0.43) and biparental mating (tm - ts=0.12) in the seed orchard may further suggest that the seed orchard was established using related seed sources.
    Matched MeSH terms: Rosales/physiology*
  11. Communal peeing: a new mode of flood control in ants
    Maschwitz U, Moog J
    Naturwissenschaften, 2000 Dec;87(12):563-5.
    PMID: 11198200
    The behavioral response of the obligate bamboo-nesting ant Cataulacus muticus to nest flooding was studied in a perhumid tropical rainforest in Malaysia and in the laboratory. The hollow internodes of giant bamboo, in which C. muticus exclusively nests, are prone to flooding by heavy rains. The ants showed a two-graded response to flooding. During heavy rain workers block the nest entrances with their heads to reduce water influx. However, rainwater may still intrude into the nest chamber. The ants respond by drinking the water, leaving the nest and excreting water droplets on the outer stem surface. This cooperative 'peeing' behavior is a new survival mechanism adaptive to the ants' nesting ecology. Laboratory experiments conducted with two other Cataulacus species, C. catuvolcus colonizing small dead twigs and C. horridus inhabiting rotten wood, did not reveal any form of water-bailing behavior.
    Matched MeSH terms: Ants/physiology*
  12. Maintaining an ant-plant symbiosis: secondary polygyny in the Macaranga triloba-Crematogaster sp. association
    Feldhaar H, Fiala B, bin Hashim R, Maschwitz U
    Naturwissenschaften, 2000 Sep;87(9):408-11.
    PMID: 11091965
    Matched MeSH terms: Ants/physiology*
  13. Fulltext Peak Expiratory Flow Rate (PEFR) in elderly Malaysians
    Lim TO
    Med J Malaysia, 1999 Dec;54(4):531-4.
    PMID: 11072478
    Matched MeSH terms: Aging/physiology*
  14. Infectivity and pathogenicity of Ascogregarina culicis (Eugregarinida: Lecudinidae) to Aedes aegypti (Diptera: Culicidae)
    Sulaiman I
    J Med Entomol, 1992 Jan;29(1):1-4.
    PMID: 1552514
    The susceptibility of three strains of Aedes aegypti (L.) to four strains of Ascogregarina culicis were studied under laboratory conditions. The parasite was found to be pathogenic to the mosquito; although pathogenicity varied among geographical strains of A. culicis and susceptibility varied among geographical strains of Ae. aegypti. In addition to affecting the survival of the mosquito larvae, infection with the parasite was found to shorten larval development time. Selected strains of A. culicis may be useful as a biological control agent against Ae. aegypti.
    Matched MeSH terms: Apicomplexa/physiology*
  15. Glycerol with fetal calf serum--a better cryoprotectant for Blastocystis hominis
    Suresh K, Init I, Reuel PA, Rajah S, Lokman H, Khairul Anuar A
    Parasitol Res, 1998;84(4):321-2.
    PMID: 9569099
    Matched MeSH terms: Blastocystis hominis/physiology*
  16. The application of a computerised recording system to smallholder dairy extension in Malaysia
    Abu Hassan MA, Kamaruddin MI, Pharo HJ
    Acta Vet Scand Suppl, 1988;84:110-2.
    PMID: 3232593
    Matched MeSH terms: Cattle/physiology*
  17. Environmental correlates of ranging behaviour in the banded langur, Presbytis melalophos
    Bennett EL
    Folia Primatol., 1986;47(1):26-38.
    PMID: 3557228
    Data are presented from a long-term study of banded langurs in three contrasting rain forest habitats in Peninsular Malaysia. Results from different sites and months are used to correlate ranging patterns with food availability and other environmental variables. Day range lengths are correlated with availability of preferred foods; the degree of territoriality is related to the distribution and size of food sources and length of time for which any one of these produces favoured food items.
    Matched MeSH terms: Cercopithecidae/physiology*
  18. Fulltext Studies on the biology of Anopheles letifer Sandosham (Diptera, Culicidae) and its response to residual spraying, carried out in Sarawak, Malaysia
    Thevasagayam ES, Liaw CF
    Med J Malaysia, 1980 Mar;34(3):254-64.
    PMID: 7191047
    Matched MeSH terms: Anopheles/physiology*
  19. Sperm abnormalities in Droughtmaster bulls
    Bongso TA, Jainudeen MR
    Trop Anim Health Prod, 1982 Feb;14(1):58.
    PMID: 7080208
    Matched MeSH terms: Cattle/physiology*
  20. A rationale for selecting suitable physiology topics for the basic sciences curriculum in dentistry
    Jiffry MT, Husain R, Dias AP
    Med Educ, 1987 Jan;21(1):38-45.
    PMID: 3821599
    The suitability of physiology topics taught in the first-year dental curriculum needs to be investigated in the light of the view of the present generation of clinical and preclinical teachers, and students. This was studied in the University of Malaya in order to propose a rational physiology curriculum with proper identification of priority topics. Oral physiology, blood and the cardiovascular system were found to be the most relevant for dental students. Among the systems, high and low priority topics were identified and their relative importance is discussed.
    Matched MeSH terms: Physiology/education*
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