Displaying publications 161 - 180 of 4601 in total

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  1. Fulltext Solitonic conduction of electrotonic signals in neuronal branchlets with polarized microstructure
    Poznanski RR, Cacha LA, Al-Wesabi YMS, Ali J, Bahadoran M, Yupapin PP, et al.
    Sci Rep, 2017 May 31;7(1):2746.
    PMID: 28566682 DOI: 10.1038/s41598-017-01849-3
    A model of solitonic conduction in neuronal branchlets with microstructure is presented. The application of cable theory to neurons with microstructure results in a nonlinear cable equation that is solved using a direct method to obtain analytical approximations of traveling wave solutions. It is shown that a linear superposition of two oppositely directed traveling waves demonstrate solitonic interaction: colliding waves can penetrate through each other, and continue fully intact as the exact pulses that entered the collision. These findings indicate that microstructure when polarized can sustain solitary waves that propagate at a constant velocity without attenuation or distortion in the absence of synaptic transmission. Solitonic conduction in a neuronal branchlet arising from polarizability of its microstructure is a novel signaling mode of electrotonic signals in thin processes (<0.5 μm diameter).
    Matched MeSH terms: Action Potentials/physiology; Dendrites/physiology; Heart Rate/physiology; Neural Conduction/physiology*; Synaptic Transmission/physiology*; Neurons/physiology*
  2. Fulltext Effects of music on arousal during imagery in elite shooters: A pilot study
    Kuan G, Morris T, Terry P
    PLoS One, 2017;12(4):e0175022.
    PMID: 28414741 DOI: 10.1371/journal.pone.0175022
    Beneficial effects of music on several performance-related aspects of sport have been reported, but the processes involved are not well understood. The purpose of the present study was to investigate effects of relaxing and arousing classical music on physiological indicators and subjective perceptions of arousal during imagery of a sport task. First, appropriate music excerpts were selected. Then, 12 skilled shooters performed shooting imagery while listening to the three preselected music excerpts in randomized order. Participants' galvanic skin response, peripheral temperature, and electromyography were monitored during music played concurrently with imagery. Subjective music ratings and physiological measures showed, as hypothesized, that unfamiliar relaxing music was the most relaxing and unfamiliar arousing music was the most arousing. Researchers should examine the impact of unfamiliar relaxing and arousing music played during imagery on subsequent performance in diverse sports. Practitioners can apply unfamiliar relaxing and arousing music with imagery to manipulate arousal level.
    Matched MeSH terms: Arousal/physiology*; Galvanic Skin Response/physiology; Imagination/physiology*; Relaxation/physiology; Sports/physiology; Athletic Performance/physiology*
  3. Fulltext Impacts of logging on density-dependent predation of dipterocarp seeds in a South East Asian rainforest
    Bagchi R, Philipson CD, Slade EM, Hector A, Phillips S, Villanueva JF, et al.
    Philos Trans R Soc Lond B Biol Sci, 2011 Nov 27;366(1582):3246-55.
    PMID: 22006965 DOI: 10.1098/rstb.2011.0034
    Much of the forest remaining in South East Asia has been selectively logged. The processes promoting species coexistence may be the key to the recovery and maintenance of diversity in these forests. One such process is the Janzen-Connell mechanism, where specialized natural enemies such as seed predators maintain diversity by inhibiting regeneration near conspecifics. In Neotropical forests, anthropogenic disturbance can disrupt the Janzen-Connell mechanism, but similar data are unavailable for South East Asia. We investigated the effects of conspecific density (two spatial scales) and distance from fruiting trees on seed and seedling survival of the canopy tree Parashorea malaanonan in unlogged and logged forests in Sabah, Malaysia. The production of mature seeds was higher in unlogged forest, perhaps because high adult densities facilitate pollination or satiate pre-dispersal predators. In both forest types, post-dispersal survival was reduced by small-scale (1 m(2)) conspecific density, but not by proximity to the nearest fruiting tree. Large-scale conspecific density (seeds per fruiting tree) reduced predation, probably by satiating predators. Higher seed production in unlogged forest, in combination with slightly higher survival, meant that recruitment was almost entirely limited to unlogged forest. Thus, while logging might not affect the Janzen-Connell mechanism at this site, it may influence the recruitment of particular species.
    Matched MeSH terms: Insects/physiology; Seeds/physiology*; Trees/physiology; Vertebrates/physiology; Seedlings/physiology; Dipterocarpaceae/physiology*
  4. The relationship of hip strength and dynamic knee valgus during single leg squat in physically active females
    Jamaludin NI, Sahabuddin FNA, Hanafi H, Shaharudin S
    J Bodyw Mov Ther, 2024 Oct;40:1238-1242.
    PMID: 39593440 DOI: 10.1016/j.jbmt.2024.07.045
    BACKGROUND: Single leg squat (SLS) is an important motion commonly observed in sports. Excessive dynamic knee valgus (DKV) during SLS may increase non-contact knee injury risks particularly in physically active females. As muscular strength plays crucial role in controlling DKV, the present study aims to evaluate the correlation between hip strength and knee frontal plane angle during SLS among females with and without excessive DKV.

    METHODS: Thirty-four volunteers were allocated to the valgus (n = 17) and non-valgus (n = 17) groups. Their motions during SLS at 45° and 60° knee flexion were captured and analyzed using three-dimensional motion analysis system. Isokinetic hip strength was examined at 180°/s in flexion, extension, abduction, and adduction for both legs. Pearson's correlation test was computed to evaluate the relationship between hip strength and knee angle during SLS.

    FINDINGS: Non-dominant hip extensor strength (r = -0.56, p = 0.02) and dominant hip adductor strength (r = -0.51, p = 0.04) were significantly related to the knee frontal plane angle during 45° SLS among those without DKV. Meanwhile, those with DKV showed a significant relationship between the knee frontal plane angle for both legs and non-dominant hip abductor strength during 60° SLS.

    INTERPRETATION: Both groups demonstrated the relationship of hip strength on knee frontal plane angle during SLS, whereby increased hip strength may minimize excessive DKV. Those with excessive DKV should train to strengthen their hip abductor to reduce knee valgus particularly during deep squats.

    Matched MeSH terms: Biomechanical Phenomena/physiology; Hip/physiology; Hip Joint/physiology; Knee/physiology; Movement/physiology; Muscle, Skeletal/physiology
  5. Energy density and weight of food effect short-term caloric compensation in men
    Mazlan N, Horgan G, Stubbs RJ
    Physiol Behav, 2006 Apr 15;87(4):679-86.
    PMID: 16545404
    The purpose of the study was to examine the effect of energy density and food weight (volume) on subsequent intake.
    Matched MeSH terms: Appetite Regulation/physiology*; Energy Intake/physiology*; Circadian Rhythm/physiology; Eating/physiology*; Food Preferences/physiology; Hunger/physiology*
  6. Retention marker excretion suggests incomplete digesta mixing across the order primates
    Matsuda I, Espinosa-Gómez FC, Ortmann S, Sha JCM, Osman I, Nijboer J, et al.
    Physiol Behav, 2019 09 01;208:112558.
    PMID: 31125579 DOI: 10.1016/j.physbeh.2019.112558
    The digestive tract of animals, and the patterns how passage markers are excreted from them, have been fruitfully compared to chemical reactor models from engineering science. An important characteristic of idealized reactor models is the smoothness of the curves plotting marker concentrations in outflow (i.e., faeces) over time, which is the result of the assumed complete mixing of the marker with the reactor contents. Published excretion patterns from passage experiments in non-primate mammals appear to indicate a high degree of digesta mixing. In order to assess whether marker excretion graphs from primates differ from ideal outflow graphs, we performed passage experiments in eight individuals of three foregut-fermenting species (Pygathrix nemaeus, Trachypithecus auratus and Semnopithecus vetulus), and added them to available marker excretion curves from the literature. In the resulting collection, 23 out of a total of 25 patterns in foregut fermenters (21 individuals of 10 species from 7 studies), and 13 out of 15 in hindgut fermenters (9 individuals of 2 species from 2 studies), showed an irregular, 'spiky' pattern. We consider this proportion to be too high to be explained by experimental errors, and suggest that this may indicate a taxon-wide characteristic of particularly incomplete digesta mixing, acknowledging that further data from less related primate species are required for corroboration. Our hypothesis is in accordance with previous findings of a comparatively low degree of 'digesta washing' (differential retention of particulate and fluid digesta) in primates. Together with literature findings that suggest a low chewing efficiency in primates compared to other mammals, these observations indicate that in contrast to other herbivores, the success of the primate order is not derived from particularly elaborate adaptations of their ingestive and digestive physiology.
    Matched MeSH terms: Defecation/physiology; Digestion/physiology; Fermentation/physiology; Gastrointestinal Transit/physiology; Primates/physiology*; Gastrointestinal Tract/physiology*
  7. Fulltext Reply to The effect of vigorous physical activity and body composition on cortical bone mass in adolescence
    Tan VP, Macdonald HM, McKay HA
    J. Bone Miner. Res., 2015 Mar;30(3):585-6.
    PMID: 25381875 DOI: 10.1002/jbmr.2399
    Matched MeSH terms: Bone and Bones/physiology*; Motor Activity/physiology*
  8. Fulltext The effects of a distracting N-back task on recognition memory are reduced by negative emotional intensity
    Buratto LG, Pottage CL, Brown C, Morrison CM, Schaefer A
    PLoS One, 2014;9(10):e110211.
    PMID: 25330251 DOI: 10.1371/journal.pone.0110211
    Memory performance is usually impaired when participants have to encode information while performing a concurrent task. Recent studies using recall tasks have found that emotional items are more resistant to such cognitive depletion effects than non-emotional items. However, when recognition tasks are used, the same effect is more elusive as recent recognition studies have obtained contradictory results. In two experiments, we provide evidence that negative emotional content can reliably reduce the effects of cognitive depletion on recognition memory only if stimuli with high levels of emotional intensity are used. In particular, we found that recognition performance for realistic pictures was impaired by a secondary 3-back working memory task during encoding if stimuli were emotionally neutral or had moderate levels of negative emotionality. In contrast, when negative pictures with high levels of emotional intensity were used, the detrimental effects of the secondary task were significantly attenuated.
    Matched MeSH terms: Attention/physiology*; Judgment/physiology
  9. Fulltext The impact of selective-logging and forest clearance for oil palm on fungal communities in Borneo
    Kerfahi D, Tripathi BM, Lee J, Edwards DP, Adams JM
    PLoS One, 2014;9(11):e111525.
    PMID: 25405609 DOI: 10.1371/journal.pone.0111525
    Tropical forests are being rapidly altered by logging, and cleared for agriculture. Understanding the effects of these land use changes on soil fungi, which play vital roles in the soil ecosystem functioning and services, is a major conservation frontier. Using 454-pyrosequencing of the ITS1 region of extracted soil DNA, we compared communities of soil fungi between unlogged, once-logged, and twice-logged rainforest, and areas cleared for oil palm, in Sabah, Malaysia. Overall fungal community composition differed significantly between forest and oil palm plantation. The OTU richness and Chao 1 were higher in forest, compared to oil palm plantation. As a proportion of total reads, Basidiomycota were more abundant in forest soil, compared to oil palm plantation soil. The turnover of fungal OTUs across space, true β-diversity, was also higher in forest than oil palm plantation. Ectomycorrhizal (EcM) fungal abundance was significantly different between land uses, with highest relative abundance (out of total fungal reads) observed in unlogged forest soil, lower abundance in logged forest, and lowest in oil palm. In their entirety, these results indicate a pervasive effect of conversion to oil palm on fungal community structure. Such wholesale changes in fungal communities might impact the long-term sustainability of oil palm agriculture. Logging also has more subtle long term effects, on relative abundance of EcM fungi, which might affect tree recruitment and nutrient cycling. However, in general the logged forest retains most of the diversity and community composition of unlogged forest.
    Matched MeSH terms: Basidiomycota/physiology; Arecaceae/physiology*
  10. Fulltext Tropical legume crop rotation and nitrogen fertilizer effects on agronomic and nitrogen efficiency of rice
    Rahman MM, Islam AM, Azirun SM, Boyce AN
    ScientificWorldJournal, 2014;2014:490841.
    PMID: 24971378 DOI: 10.1155/2014/490841
    Bush bean, long bean, mung bean, and winged bean plants were grown with N fertilizer at rates of 0, 2, 4, and 6 g N m(-2) preceding rice planting. Concurrently, rice was grown with N fertilizer at rates of 0, 4, 8, and 12 g N m(-2). No chemical fertilizer was used in the 2nd year of crop to estimate the nitrogen agronomic efficiency (NAE), nitrogen recovery efficiency (NRE), N uptake, and rice yield when legume crops were grown in rotation with rice. Rice after winged bean grown with N at the rate of 4 g N m(-2) achieved significantly higher NRE, NAE, and N uptake in both years. Rice after winged bean grown without N fertilizer produced 13-23% higher grain yield than rice after fallow rotation with 8 g N m(-2). The results revealed that rice after winged bean without fertilizer and rice after long bean with N fertilizer at the rate of 4 g N m(-2) can produce rice yield equivalent to that of rice after fallow with N fertilizer at rates of 8 g N m(-2). The NAE, NRE, and harvest index values for rice after winged bean or other legume crop rotation indicated a positive response for rice production without deteriorating soil fertility.
    Matched MeSH terms: Fabaceae/physiology*; Oryza/physiology*
  11. Hybrid markerless tracking of complex articulated motion in golf swings
    Fung SK, Sundaraj K, Ahamed NU, Kiang LC, Nadarajah S, Sahayadhas A, et al.
    J Bodyw Mov Ther, 2014 Apr;18(2):220-7.
    PMID: 24725790 DOI: 10.1016/j.jbmt.2013.05.011
    Sports video tracking is a research topic that has attained increasing attention due to its high commercial potential. A number of sports, including tennis, soccer, gymnastics, running, golf, badminton and cricket have been utilised to display the novel ideas in sports motion tracking. The main challenge associated with this research concerns the extraction of a highly complex articulated motion from a video scene. Our research focuses on the development of a markerless human motion tracking system that tracks the major body parts of an athlete straight from a sports broadcast video. We proposed a hybrid tracking method, which consists of a combination of three algorithms (pyramidal Lucas-Kanade optical flow (LK), normalised correlation-based template matching and background subtraction), to track the golfer's head, body, hands, shoulders, knees and feet during a full swing. We then match, track and map the results onto a 2D articulated human stick model to represent the pose of the golfer over time. Our work was tested using two video broadcasts of a golfer, and we obtained satisfactory results. The current outcomes of this research can play an important role in enhancing the performance of a golfer, provide vital information to sports medicine practitioners by providing technically sound guidance on movements and should assist to diminish the risk of golfing injuries.
    Matched MeSH terms: Golf/physiology*; Movement/physiology*
  12. Fulltext The effect on human balance of standing with toe-extension
    Ku PX, Abu Osman NA, Yusof A, Wan Abas WA
    PLoS One, 2012;7(7):e41539.
    PMID: 22848523 DOI: 10.1371/journal.pone.0041539
    Postural balance is vital for safely carrying out many daily activities, such as locomotion. The purpose of this study was to determine how changes in normal standing (NS) and standing with toe-extension (SWT) impact postural control during quiet standing. Furthermore, the research aimed to examine the extent to which the effect of these factors differed between genders.
    Matched MeSH terms: Postural Balance/physiology*; Posture/physiology*
  13. Fulltext Intraspecific crossability in Andrographis paniculata Nees: a barrier against breeding of the species
    Valdiani A, Abdul Kadir M, Said Saad M, Talei D, Omidvar V, Hua CS
    ScientificWorldJournal, 2012;2012:297545.
    PMID: 22701352 DOI: 10.1100/2012/297545
    The ambiguity of crossability in Andrographis paniculata (AP) was pointed out in the present research. Accordingly, the effects of different style length and crossing time on intraspecific crossability of seven AP accessions in 21 possible combinations were investigated. The best results came out between 08:00 to 11:00 h for manual out-crossing of AP, while the time from 12:00 to 18:00 h showed a decreasing trend. Moreover, 12 mm style length was found as the most proper phenological stage in terms of stigmatic receptivity to perform out-crossing in this plant. All in all, AP behaved unlikely in each combination, and a significant difference was observed in crossability of AP accessions (P < 0.01). The lowest and highest crossability rate was found in hybrids 21 (11261NS × 11344K) and 27 (11322PA × 11350T) with 0.25% and 13.33%, respectively. Furthermore, a significant negative relationship between style length and crossibility (r² = 0.762(∗∗)) was recorded in this research. As a final conclusion, crossing time and proper style length can improve the intraspecific crossability in the species, considerably. Despite all the mentioned contrivances, we still believe that a genetic incongruity should be involved as an additional obstacle in crossability of those combinations that failed or responded deficiently to outcrossing.
    Matched MeSH terms: Hybridization, Genetic/physiology*; Andrographis/physiology*
  14. Effects of temperature and humidity on the survival and water loss of Cimex hemipterus (Hemiptera: Cimicidae)
    How YF, Lee CY
    J Med Entomol, 2010 Nov;47(6):987-95.
    PMID: 21175045
    The effect of temperature and humidity on the survival and water loss of the tropical bed bug, Cimex hemipterus (F.), was studied using two field-collected strains. Insects were exposed to temperatures ranging from 20 to 45 degrees C and relative humidities (RHs) of 33, 75, and 100%. C. hemipterus survived longest under the interaction of low temperature (20 degrees C) and high RH (75-100%). Survival and water loss were significantly affected (P < 0.01) by temperature and RH (either singly, or in interaction). Strain and sex significantly (P < 0.01) influenced bed bug survival, but not on water loss. Eggs, first instars, and adults reached their upper thermal lethal limit within 1 h at 39 degrees C, 44 degrees C, and 46 degrees C, respectively. The survival and water loss profiles showed that starved C. hemipterus started to die after losing 35-45% of their body weights.
    Matched MeSH terms: Bedbugs/physiology*; Water Loss, Insensible/physiology*
  15. Anthropometry and body composition in soccer and volleyball players in West Bengal, India
    Bandyopadhyay A
    J Physiol Anthropol, 2007 Jun;26(4):501-5.
    PMID: 17704629
    50 sedentary males and 128 sports persons (volleyball=82, soccer=46) of 20-24 years were selected from West Bengal, India, to evaluate and compare their anthropometry and body composition. Skinfolds, girth measurements, body fat percentage (%fat), and endomorphy were significantly higher among sedentary individuals, but lean body mass (LBM) and mesomorphy were significantly (p<0.001) higher among the sports persons. Soccer and volleyball players were found to be ectomorphic mesomorph, whereas sedentary subjects were endomorphic mesomorph. The soccer and volleyball players had higher %fat with lower body height and body mass than their overseas counterparts. %fat exhibited a significant correlation with body mass index (BMI) and thus prediction equations for %fat from BMI were computed in each group. The present data will serve as a reference standard for the anthropometry and body composition of Indian soccer and volleyball players and the prediction norms for %fat will help to provide a first-hand impression of body composition in the studied population.
    Matched MeSH terms: Soccer/physiology*; Somatotypes/physiology*
  16. Intracellular capacitive effects of polarized proteins in dendrites
    Poznanski RR, Cacha LA
    J Integr Neurosci, 2012 Dec;11(4):417-37.
    PMID: 23351050 DOI: 10.1142/S0219635212500264
    Passive dendrites become active as a result of electrostatic interactions by dielectric polarization in proteins in a segment of a dendrite. The resultant nonlinear cable equation for a cylindrical volume representation of a dendritic segment is derived from Maxwell's equations under assumptions: (i) the electric field is restricted longitudinally along the cable length; (ii) extracellular isopotentiality; (iii) quasi-electrostatic conditions; (iv) isotropic membrane and homogeneous medium with constant conductivity; and (v) protein polarization contributes to intracellular capacitive effects through a well defined nonlinear capacity-voltage characteristic; (vi) intracellular resistance and capacitance in parallel are connected to the membrane in series. Under the above hypotheses, traveling wave solutions of the cable equation are obtained as propagating fronts of electrical excitation associated with capacitive charge-equalization and dispersion of continuous polarization charge densities in an Ohmic cable. The intracellular capacitative effects of polarized proteins in dendrites contribute to the conduction process.
    Matched MeSH terms: Dendrites/physiology*; Proteins/physiology*
  17. Occurrence of infanticide among wild proboscis monkeys (Nasalis larvatus) in Sabah, Northern Borneo
    Agoramoorthy G, Hsu MJ
    Folia Primatol., 2005;76(3):177-9.
    PMID: 15900105
    Matched MeSH terms: Behavior, Animal/physiology*; Colobinae/physiology*
  18. Fulltext Coral community response to bleaching on a highly disturbed reef
    Guest JR, Low J, Tun K, Wilson B, Ng C, Raingeard D, et al.
    Sci Rep, 2016 Feb 15;6:20717.
    PMID: 26876092 DOI: 10.1038/srep20717
    While many studies of coral bleaching report on broad, regional scale responses, fewer examine variation in susceptibility among coral taxa and changes in community structure, before, during and after bleaching on individual reefs. Here we report in detail on the response to bleaching by a coral community on a highly disturbed reef site south of mainland Singapore before, during and after a major thermal anomaly in 2010. To estimate the capacity for resistance to thermal stress, we report on: a) overall bleaching severity during and after the event, b) differences in bleaching susceptibility among taxa during the event, and c) changes in coral community structure one year before and after bleaching. Approximately two thirds of colonies bleached, however, post-bleaching recovery was quite rapid and, importantly, coral taxa that are usually highly susceptible were relatively unaffected. Although total coral cover declined, there was no significant change in coral taxonomic community structure before and after bleaching. Several factors may have contributed to the overall high resistance of corals at this site including Symbiodinium affiliation, turbidity and heterotrophy. Our results suggest that, despite experiencing chronic anthropogenic disturbances, turbid shallow reef communities may be remarkably resilient to acute thermal stress.
    Matched MeSH terms: Anthozoa/physiology*; Disease Resistance/physiology*
  19. Fulltext Ringed Seal Search for Global Optimization via a Sensitive Search Model
    Saadi Y, Yanto IT, Herawan T, Balakrishnan V, Chiroma H, Risnumawan A
    PLoS One, 2016;11(1):e0144371.
    PMID: 26790131 DOI: 10.1371/journal.pone.0144371
    The efficiency of a metaheuristic algorithm for global optimization is based on its ability to search and find the global optimum. However, a good search often requires to be balanced between exploration and exploitation of the search space. In this paper, a new metaheuristic algorithm called Ringed Seal Search (RSS) is introduced. It is inspired by the natural behavior of the seal pup. This algorithm mimics the seal pup movement behavior and its ability to search and choose the best lair to escape predators. The scenario starts once the seal mother gives birth to a new pup in a birthing lair that is constructed for this purpose. The seal pup strategy consists of searching and selecting the best lair by performing a random walk to find a new lair. Affected by the sensitive nature of seals against external noise emitted by predators, the random walk of the seal pup takes two different search states, normal state and urgent state. In the normal state, the pup performs an intensive search between closely adjacent lairs; this movement is modeled via a Brownian walk. In an urgent state, the pup leaves the proximity area and performs an extensive search to find a new lair from sparse targets; this movement is modeled via a Levy walk. The switch between these two states is realized by the random noise emitted by predators. The algorithm keeps switching between normal and urgent states until the global optimum is reached. Tests and validations were performed using fifteen benchmark test functions to compare the performance of RSS with other baseline algorithms. The results show that RSS is more efficient than Genetic Algorithm, Particles Swarm Optimization and Cuckoo Search in terms of convergence rate to the global optimum. The RSS shows an improvement in terms of balance between exploration (extensive) and exploitation (intensive) of the search space. The RSS can efficiently mimic seal pups behavior to find best lair and provide a new algorithm to be used in global optimization problems.
    Matched MeSH terms: Behavior, Animal/physiology*; Seals, Earless/physiology*
  20. A new form of tool use by orang-utans in Sabah, East Malaysia
    Rogers LJ, Kaplan G
    Folia Primatol., 1994;63(1):50-2.
    PMID: 7813972
    Matched MeSH terms: Feeding Behavior/physiology*; Pongo pygmaeus/physiology*
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