265 research outputs found

    Tracking Shock Movement on the Surface of an Oscillating, Straked Semispan Delta Wing

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    A recent research effort, sponsored by the Air Force Office of Scientific Research, numerically investigated the unsteady aerodynamic flow field around an oscillating, straked, delta wing. The study was centered on determining the importance of the unsteady aerodynamic forces acting as a driver for a nonlinear motion known as limit cycle oscillations. The current effort focused on creating a computational model to compare to the results of previous tests and modeling efforts and discover new information regarding the onset of LCO. The computational model was constructed using the Cartesian overset capabilities of the CREATE-AV™ fixed wing fluid dynamics solver Kestrel. The geometry of the model was based on an Euler model that was recently developed to investigate the same experiments. Adaptive mesh refinement was also employed during the numerical simulations to better capture the translation of the shock along the surface of the semispan. The developed numerical model was tested at a variety of flow conditions, including varying free-stream Mach numbers, starting trim angles, oscillation amplitudes and oscillation frequencies. The results showed a number of trends that could influence the onset and sustainment of LCO. First, the aerodynamic phenomena of shock-induced trailing edge separation (SITES) was observed during a number of the simulations. Popular among aeroelasticians as a possible source of LCO, SITES is thought to cause a change in the aerodynamic forces acting on the flexible structure, propagating the LCO motion. Second, the quantitative results of the computational model showed good agreement with published, qualitative observations made during wind tunnel experiments. Third, a separation bubble was observed aft a shock on the top surface of the semispan. This previously unobserved flow feature could have a significant impact on the forces acting on the model during the oscillation

    The Permanence of Temporary Services: The Reliance of Canadian Federal Departments on Policy & Management Consultants

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    Canadian Public Administration563369-39

    Association of Blood Pressure and Fitness With Levels of Atherosclerotic Risk Markers Pre-Exercise and Post-exercise

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    Background: Physical fitness may attenuate the increased atherosclerotic risk in patients with systemic hypertension. We investigated the association of screening blood pressure (BP) and cardiorespiratory fitness with baseline levels and exercise-induced changes in levels of soluble atherosclerotic risk markers. Methods: Twenty-six otherwise healthy and unmedicated subjects with elevated BP (systolic BP and/or diastolic BP ≥130/85 mm Hg) and 40 subjects with normal BP underwent 20-min treadmill exercise at 65% to 70% of predetermined peak oxygen consumption (VO2peak). Interleukin (IL)-6, soluble intercellular adhesion molecule (sICAM)-1, von Willebrand factor (VWF) antigen, and plasminogen activator inhibitor (PAI)-1 antigen were measured at baseline (ie, pre-exercise), early postexercise, and late postexercise (ie, 25 min after exercise). Results: At baseline, higher screening mean arterial BP (MAP) independently predicted higher sICAM-1 levels (P = .031), and lower VO2peak independently predicted higher IL-6 (P = .016) and PAI-1 (P < .001) levels. Early and late postexercise lower VO2peak was associated with higher mean PAI-1 (P ≤ .072) and IL-6 (P ≤ .026) levels, and higher screening MAP was associated with higher mean sICAM-1 levels (P ≤ .035). Higher VO2peak was associated with a greater PAI-1 increase from baseline to early postexercise in subjects with elevated BP (P = .045) but not in those with normal BP. Conclusions: Circulating levels of some atherosclerotic risk markers at baseline and with exercise were higher with elevated BP and lower with better fitness. Greater fitness did not particularly protect subjects with elevated BP from potentially harmful responses of atherosclerotic risk markers to acute physical exercise. Am J Hypertens 2007;20: 670-675 © 2007 American Journal of Hypertension, Lt

    Depressive symptoms in asymptomatic stage B heart failure with Type II diabetic mellitus.

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    BackgroundThe presence of concomitant Type II diabetic mellitus (T2DM) and depressive symptoms adversely affects individuals with symptomatic heart failure (HF).HypothesisIn presymptomatic stage B HF, this study hypothesized the presence of greater inflammation and depressive symptoms in T2DM as compared to non-T2DM Stage B patients.MethodsThis cross-sectional study examined clinical parameters, inflammatory biomarkers, and depressive symptoms in 349 T2DM and non-T2DM men with asymptomatic stage B HF (mean age 66.4 years ±10.1; range 30-91).ResultsFewer diabetic HF patients had left ventricular (LV) systolic dysfunction (P &lt; .05) although more had LV diastolic dysfunction (P &lt; .001). A higher percentage of T2DM HF patients were taking ACE-inhibitors, beta-blockers, calcium channel blockers, statins, and diuretics (P values &lt; .05). T2DM HF patients had higher circulating levels of interleukin-6 (IL-6) (P &lt; .01), tumor necrosis factor-alpha (P &lt; .01), and soluble ST2 (sST2) (P &lt; .01) and reported more somatic/affective depressive symptoms (Beck Depression Inventory II) (P &lt; .05) but not cognitive/affective depressive symptoms (P = .20). Among all patients, in a multiple regression analysis predicting presence of somatic/affective depressive symptoms, sST2 (P = .026), IL-6 (P = .010), B-type natriuretic peptide (P = .016), and sleep (Pittsburgh Sleep Quality Index [P &lt; .001]) were significant predictors (overall model F = 15.39, P &lt; .001, adjusted R2 = .207).ConclusionsSomatic/affective but not cognitive/affective depressive symptoms are elevated in asymptomatic HF patients with T2DM patients. Linkages with elevated inflammatory and cardiac relevant biomarkers suggest shared pathophysiological mechanisms among T2DM HF patients with somatic depression, and these conditions are responsive to routine interventions, including behavioral. Copyright © 2019 John Wiley &amp; Sons, Ltd

    A contrastive study between Australian and Malaysian women’s online advice-seeking strategies on IVF. Proceedings of the 3rd International Conference on Language Studies 2021 (pp. 7-12). Universiti Malaysia Sarawak.

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    With the advent of technology and the Internet, studies on communication strategies have shifted from face-to-face interactions to computer-mediated communication. However, research on online advice-seeking strategies focusing on specific cultural groups are limited, and have centred largely on the North American (Locher, 2006), European (Placencia, 2012), and the East Asian regions (Morrow, 2012). The present study is a contrastive study comparing the online advice-seeking strategies between an eastern society (Malaysia) and a western society (Australia). A content analysis approach was employed, emulating Kouper’s (2010) and Locher's (2006) method of analysing online advice messages. The findings showed that although both forums were similar in many aspects, there were some variations in the women’s advice-seeking strategies, indicating influence of different cultural backgrounds and different needs of Australian women and Malaysian women

    Bim: the setback or solution to project cost issues in Malaysia construction industry?

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    Malaysia is progressing into Industry Revolution (IR) 4.0 which emphasizes more onto digital, data and artificial intelligence where everything is expected to be automated. However, cost tends to be a major issue at the pioneer stage of embracing technology where Building Information Modelling (BIM) for example tends to be a cost tussle for the current construction industry. Yet, research has shown that BIM is arguably one of the technology platforms in combating the costing issue considering that BIM enables 3D model elements to link to cost and auto-generate quantities which potentially achieve cost-effective project. Due to the conflicting perspectives of how BIM affects project cost issues, it is imperative to investigate the cost-related issues in implementing BIM in the project and to determine how BIM in general positively influences the overall project cost. Qualitative research is adopted in this study. A semi-structured interview was conducted among four professionals who employs BIM in their project. They consist of the assistant manager, senior manager and chief executive officer. The data collected is analysed by utilising Matrix Table for better organisation. The scope of the study is in the Selangor state in which the local construction industry had applied BIM in their construction industry up to the 3D stage. The results showed that the BIM implementation cost is not too burdensome as it is only a one-time cost and does not vary throughout the project period. In addition, the BIM influence on the overall cost of the project is beneficial to the industry. It improves workflow and cost management. In conclusion, BIM is beneficial to the construction industry in the long term. It is important to resolve the costrelated issues for implement BIM and hence, encourage the usage of BIM, especially in the IR 4.0 ecosyste

    Zona Pellucida Domain-Containing Protein β-Tectorin is Crucial for Zebrafish Proper Inner Ear Development

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    BACKGROUND: The zona pellucida (ZP) domain is part of many extracellular proteins with diverse functions from structural components to receptors. The mammalian β-tectorin is a protein of 336 amino acid residues containing a single ZP domain and a putative signal peptide at the N-terminus of the protein. It is 1 component of a gel-like structure called the tectorial membrane which is involved in transforming sound waves into neuronal signals and is important for normal auditory function. β-Tectorin is specifically expressed in the mammalian and avian inner ear. METHODOLOGY/PRINCIPAL FINDINGS: We identified and cloned the gene encoding zebrafish β-tectorin. Through whole-mount in situ hybridization, we demonstrated that β-tectorin messenger RNA was expressed in the otic placode and specialized sensory patch of the inner ear during zebrafish embryonic stages. Morpholino knockdown of zebrafish β-tectorin affected the position and number of otoliths in the ears of morphants. Finally, swimming behaviors of β-tectorin morphants were abnormal since the development of the inner ear was compromised. CONCLUSIONS/SIGNIFICANCE: Our results reveal that zebrafish β-tectorin is specifically expressed in the zebrafish inner ear, and is important for regulating the development of the zebrafish inner ear. Lack of zebrafish β-tectorin caused severe defects in inner ear formation of otoliths and function

    Exploring Uncoupling Proteins and Antioxidant Mechanisms under Acute Cold Exposure in Brains of Fish

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    Exposure to fluctuating temperatures accelerates the mitochondrial respiration and increases the formation of mitochondrial reactive oxygen species (ROS) in ectothermic vertebrates including fish. To date, little is known on potential oxidative damage and on protective antioxidative defense mechanisms in the brain of fish under cold shock. In this study, the concentration of cellular protein carbonyls in brain was significantly increased by 38% within 1 h after cold exposure (from 28°C to 18°C) of zebrafish (Danio rerio). In addition, the specific activity of superoxide dismutase (SOD) and the mRNA level of catalase (CAT) were increased after cold exposure by about 60% (6 h) and by 60%–90% (1 and 24 h), respectively, while the specific glutathione content as well as the ratio of glutathione disulfide to glutathione remained constant and at a very low level. In addition, cold exposure increased the protein level of hypoxia-inducible factor (HIF) by about 50% and the mRNA level of the glucose transporter zglut3 in brain by 50%–100%. To test for an involvement of uncoupling proteins (UCPs) in the cold adaptation of zebrafish, five UCP members were annotated and identified (zucp1-5). With the exception of zucp1, the mRNA levels of the other four zucps were significantly increased after cold exposure. In addition, the mRNA levels of four of the fish homologs (zppar) of the peroxisome proliferator-activated receptor (PPAR) were increased after cold exposure. These data suggest that PPARs and UCPs are involved in the alterations observed in zebrafish brain after exposure to 18°C. The observed stimulation of the PPAR-UCP axis may help to prevent oxidative damage and to maintain metabolic balance and cellular homeostasis in the brains of ectothermic zebrafish upon cold exposure
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