19672 research outputs found
Sort by
Beetles Species Richness along Environmental Gradients at Montane Ecosystem in Fraser's Hill, Peninsular Malaysia
No full textThis study measures beetle diversity and distribution pattern along elevations at Fraser’s Hill, a pristine tropical forest in Malaysia. Sites were sampled at 500 m, 1000 m, 1500 m and 1800 m a.s.l. using two light traps, two Malaise traps and 25 pitfall traps at each elevation. Sampling was carried out at three months’ intervals in 2015. Altogether, 1981 beetles representing 32 families and 116 species were collected, with proportion of obtained species above 70% at all elevations. Species richness was not significant among elevations, thus forming no discernible pattern of species distribution. Higher Shannon diversity increased steadily with elevation and dominance was lowest at the two highest elevations, while beetle abundance decreases significantly with elevation. There was no significant difference between the diversity values at 500 m and 1000 m, and 1500 m and 1800 m, whereas there was significant difference between 500 m and 1500 m, and 1000 m and 1800 m. The results highlight the importance of different microhabitats for different beetle species and their own responses to environmental parameters that differ with altitudinal clines. These findings also highlight the importance of Fraser’s Hill as a key location for biological conservation and as protected area. © 2019 Penerbit Universiti Kebangsaan Malaysia. All rights reserved
The Association of Breakfast Frequency and Cardiovascular Disease (CVD) Risk Factors among Adolescents in Malaysia
No full textBreakfast frequency is associated with cardiovascular disease (CVD) risk in Western populations, possibly via the types of food eaten or the timing of food consumption, but associations in Malaysian adolescents are unknown. While the timing of breakfast is similar, the type of food consumed at breakfast in Malaysia differs from Western diets, which allows novel insight into the mechanisms underlying breakfast–CVD risk associations. We investigated foods eaten for breakfast and associations between breakfast frequency and CVD risk factors in the Malaysian Health and Adolescents Longitudinal Research Team study (MyHeARTs). Breakfast (frequency of any food/drink reported as breakfast in 7-day diet history interviews) and CVD risk factors (body mass index (BMI), waist circumference, fasting blood glucose, triacylglycerol, total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and systolic and diastolic blood pressure) were cross-sectionally associated using linear regression adjusting for potential confounders (n = 795, age 13 years). Twelve percent of adolescents never ate breakfast and 50% ate breakfast daily, containing mean (SD) 400 (±127) kilocalories. Commonly consumed breakfast foods were cereal-based dishes (primarily rice), confectionery (primarily sugar), hot/powdered drinks (primarily Milo), and high-fat milk (primarily sweetened condensed milk). After adjustment, each extra day of breakfast consumption per week was associated with a lower BMI (−0.34 kg/m2, 95% confidence interval (CI) −0.02, −0.66), and serum total (−0.07 mmol/L 95% CI −0.02, −0.13) and LDL (−0.07 mmol/L 95% CI −0.02, −0.12) cholesterol concentrations. Eating daily breakfast in Malaysia was associated with slightly lower BMI and total and LDL cholesterol concentrations among adolescents. Longitudinal studies and randomized trials could further establish causality. © 2019 by the authors. Licensee MDPI, Basel, Switzerland
Passive Q-switching operation of erbium-doped fiber laser with gold nanoparticles embedded into PVA film as saturable absorber
No full textWe demonstrate a Q-switched Erbium-doped fiber laser (EDFL) using a newly developed gold nanoparticles (GNPs) based saturable absorber (SA) for the first time. The GNPs were embedded in polyvinyl alcohol (PVA) for film-forming and inserted into an Erbium-doped fiber laser (EDFL) cavity to achieve passive Q-switching. The Q-switched EDFL operates at 1560 nm with a pump power threshold of 35 mW, a pulse repetition rate tunable from 19.7 to 89.9 kHz, and the smallest pulse-width of 2.64 µs. The Q-switching pulse shows no spectral modulation with a peak-to-pedestal ratio of 69 dB indicating the high stability of the laser. The highest pulse energy of 103 nJ was obtained at 118 mW pump power. These results show that the GNPs based SA is available for pulsed operation in the 1550 nm spectral range. © 2019, S.C. Virtual Company of Phisics S.R.L. All right reserved
Performance of wild-Serbian Ganoderma lucidum mycelium in treating synthetic sewage loading using batch bioreactor
No full textThe fluctuation of domestic wastewater characteristic inhibits the current conventional microbial-based treatment. The bioremediation fungi has received attention and reported to be an effective alternative to treat industrial wastewater. Similar efficient performance is envisaged for domestic wastewater whereby assessed performance of fungi for varying carbon-to-nitrogen ratios in domestic wastewater is crucial. Thus, the performance of pre-grown wild-Serbian Ganoderma lucidum mycelial pellets (GLMPs) was evaluated on four different synthetic domestic wastewaters under different conditions of initial pH (pH 4, 5, and 7) and chemical oxygen demand (COD) to nitrogen (COD/N) ratio of 3.6:1, 7.1:1, 14.2:1, and 17.8:1 (C3.6N1, C7.1N1, C14.2N1, and C17.8N1). The COD/N ratios with a constant concentration of ammonia–nitrogen (NH3–N) were chosen on the basis of the urban domestic wastewater characteristics sampled at the inlet basin of a sewage treatment plant (STP). The parameters of pH, COD, and NH3–N were measured periodically during the experiment. The wild-Serbian GLMPs efficiently removed the pollutants from the synthetic sewage. The COD/N ratio of C17.8N1 wastewater had the best COD and NH3–N removal, as compared to the lower COD/N ratio, and the shortest treatment time was obtained in an acidic environment at pH 4. The highest percentage for COD and NH3–N removal achieved was 96.0% and 93.2%, respectively. The results proved that the mycelium of GLMP has high potential in treating domestic wastewater, particularly at high organic content as a naturally sustainable bioremediation system. © 2019, The Author(s)
Efficient hydrogen gas production from molasses in hybrid anaerobic-activated sludge-rotating biological contactor
No full textA hybrid anaerobic activated sludge and rotating biological contactor (AnAS-RBC) reactor with sludge return was investigated for biological hydrogen production from molasses by a mixed culture of hydrogen-producing bacteria via a dark fermentation process. The pH was not controlled during the experiments. The effects of organic loading rate (OLR) and disk rotational speed (DRS) on process performance were studied using response surface methodology. Both OLR and DRS showed significant effects on all process responses. High levels of DRS were found favorable for efficient process. Optimal mixing of the bacterial culture contributed towards higher acetate production resulting in higher hydrogen production. The highest hydrogen production (168 mL/g COD) was achieved by applying OLR and DRS of 23 g/L.d and 30 rpm, respectively. In this study, the highest percentage of hydrogen in biogas produced was 87% in hydraulic retention time of 12 h. © 2018 Hydrogen Energy Publications LL
Electrically evoked wrist extensor muscle fatigue throughout repetitive motion as measured by mechanomyography and near-infrared spectroscopy
No full textRepetitive electrically-evoked muscle contraction leads to accelerated muscle fatigue. This study assessed electrically-evoked fatiguing muscle with changes to mechanomyography root mean square percentage (%RMS-MMG) and tissue saturation index (%TSI) in extensor carpi radialis. Forty healthy volunteers (n=40) performed repetitive electrical-evoked wrist extension to fatigue and results were analyzed pre- and post-fatigue, i.e. 50% power output (%PO) drop. Responses of %PO, %TSI and %RMS-MMG were correlated while the relationships between %RMS-MMG and %TSI were investigated using linear regression. The %TSI for both groups were negatively correlated with declining %PO as the ability of the muscle to take up oxygen became limited due to fatigued muscle. The %RMS-MMG behaved in two different patterns post-fatigue against declining %PO whereby; (i) group A showed positive correlation (%RMS-MMG decreased) throughout the session and (ii) group B demonstrated negative correlation (%RMS-MMG increased) with declining %PO until the end of the session. Regression analysis showed %TSI was inversely proportional to %RMS-MMG during post-fatigue in group A. Small gradients in both groups suggested that %TSI was not sensitive to the changes in %RMS-MMG and they were mutually exclusive. Most correlation and regression changed significantly post-fatigue indicating that after fatigue, the condition of muscle had changed mechanically and physiologically. © 2019 Walter de Gruyter GmbH, Berlin/Boston
Socioemotional wealth and family commitment
No full textPurpose: The purpose of this paper is to determine the elements of family-centric non-economic goals, such as socioemotional wealth (SEW) of family business owners, that drive family commitment. The empirical study further tests whether such relationships are impacted by the aspect of ownership, that is, who controls the firm: founder generation or subsequent generation of owner managers. Design/methodology/approach: Deploying the SEW and stakeholder theories, this study proposes a conceptual link between soecioemotional wealth dimensions and family commitment. The study is based on a survey of 357 private family firms in Bangladesh involved in manufacturing ready-made garments. The respondents are all in senior-level management positions in their respective firms and are members of the dominant owning family. Findings: Prior to considering the moderating effect of controlling generation, the results indicate that four out of five FIBER dimensions of SEW affect family commitment, except for binding social ties. The study also finds that when a comparison is made between the founder generation and the subsequent generation of family firm managers, it is the latter that manifests significantly higher levels of family commitment when the focus is on the two FIBER dimensions of SEW: binding social ties and identification of family members with the firm. Research limitations/implications: Although the cross-sectional nature of the study exposes the study to the specter of common method bias, procedural remedies were initiated to minimize the likelihood. Furthermore, data were collected from a single key informant in each organization. Therefore, both a longitudinal study and corroborating data from more than one individual in each firm would possibly provide a more robust picture. Practical implications: Key decision makers from within the family who wish to see their subsequent generation remain engaged and committed to the family firm may find cues from the fact that focusing on binding social ties and identification of family members with the firm play an important role in ensuring continued commitment to the business by their successors. Social implications: Family businesses are recognized to be vital contributors to most societies around the globe, both as employment generators as well as catalysts of economic activities. Hence, policy makers may derive pertinent information from the study in adopting policies to nurture and ensure survival and continuity of family-owned businesses, by understanding how family-centric non-economic goals impact family’s desire to commit resources, time and effort to the enterprise from generation to generation. Originality/value: Determining the factors that drive continued engagement and commitment of family members to the business enterprise is a phenomenon that needs to be better understood in order to ensure continuity and survival of family enterprises across generations. This study attempts to provide a more nuanced understanding of how different components of family-centric goals, such as SEW, impact family commitment. The study contributes to theory building by providing a conceptual link that demonstrates the components of SEW that are most pertinent in terms of ensuring higher levels of family commitment to the family-owned business. © 2019, Emerald Publishing Limited
Relative Comprehensiveness of Performance Measurement System: Organisational Ownership Structure and Size
No full textChange in the business environment has resulted in significant implication in the use of Management Control System (MCS) particularly Performance Measurement System (PMS). Strategic Performance Measurement System (SPMS) has been widely used by organisation to monitor the implementation, achievement and improvement of its plan objectives. Considerable prior research identified inconsistent findings in the relationship between PMS and organisational performance. In view of the fact that organisational culture would significantly being influenced by ownership structure, this research will further explore the comprehensiveness of PMS, the extent to which the systems provide information and integration with strategy and value chain, with different ownership structure. Data were gathered in two (2) phases; firstly, using the survey data administered to the 120 strategic business unit (SBU) managers of the manufacturing companies, members of the Federation of Malaysian Manufacturers (FMM). The second phase involves conducting semi-structured interviews with SBU managers of the 10 companies with foreign and local ownership structure. Findings from the research identified that more comprehensive PMS is being implemented by foreign owned companies rather than local own companies. The size of the companies may also influence the PMS comprehensiveness. The PMS implementation was also found to be influenced by the parent companies. Adequate information technology (IT) plays an important role for effective use of the PMS, provide added supports for performance assessment, communication and exchange of information within the organisation and inter-organisations worldwide. Findings provide significant insights into the organisational factors influence the PMS design. © Sciedu Press
A Half-Circular Distribution on a Circle
No full textUp to now, circular distributions are defined in [0,2 π), except for axial distributions on a semicircle. However, some circular data lie within just half of this range and thus may be better fitted by a half-circular distribution, which we propose and develop in this paper using the inverse stereographic projection technique on a gamma distributed variable. The basic properties of the distribution are derived while its parameters are estimated using the maximum likelihood estimation method. We show the practical value of the distribution by applying it to an eye data set obtained from a glaucoma clinic at the University of Malaya Medical Centre, Malaysia. © 2019 Penerbit Universiti Kebangsaan Malaysia. All rights reserved
Passively Q-switched fiber laser utilizing new hafnium–bismuth–erbium co-doped fiber as saturable absorber
No full textA stable all-fiber passively Q-switched erbium-doped fiber laser emitting at 1559 nm is proposed and demonstrated using an 8-cm-long hafnium–bismuth–erbium co-doped fiber (HBEDF) as a saturable absorber (SA). The HBEDF is fabricated in-house and has a linear absorption of around 5.2 dB at the laser operating wavelength of 1559 nm. The Q-switching pulses are obtained with an input pump power ranging from 50 to 121 mW. It has the pulse repetition rate of 81.57 kHz, the shortest pulse width of 3.31 µs, output power of 10 mW, pulse energy of 123 nJ and peak power of 37.3 mW at the maximum pump power of 121 mW. The corresponding signal-to-noise ratio of the electrical spectrum is measured to be around 70 dB, which indicates the stability of the laser. To the best of our knowledge, this is the first demonstration of the deployment of HBEDF SA in generating a robust and steady pulsed laser in 1.5-micron region. © 2019, Indian Association for the Cultivation of Science