1,204 research outputs found

    A Versatile Active Block: DXCCCII and Tunable Applications

    Get PDF
    The study describes dual-X controlled current conveyor (DXCCCII) as a versatile active block and its application to inductance simulators for testing. Moreover, the high pass filter application using with DXCCCII based inductance simulator and oscillator with flexible tunable oscillation frequency have been presented and simulated to confirm the theoretical validity. The proposed circuit which has a simple circuit design requires the low-voltage and the DXCCCII can also be tuned in the wide range by the biasing current. The proposed DXCCCII provides a good linearity, high output impedance at Z terminals, and a reasonable current and voltage transfer gain accuracy. The proposed DXCCCII and its applications have been simulated using the CMOS 0.18 µm technology

    The Effects of Shear and Rotation Anisotropy Upon the Process of Gravitational Instability

    Full text link
    In this paper, we study the role of shear fields on the evolution of density perturbations embedded in a Friedmann flat background universe, by studying the evolution of a homogeneous ellipsoid model. In this context, we show that while the effect of the shear is that of increasing the growth rate of the density contrast of a mass element, the angular momentum acquired by the ellipsoid has the right magnitude to counterbalance the shear. Finally, our result show that initial asphericities and tidal interaction induce a slowing down of the collapse after the system has broken away from the general expansion, in perfect agreement with the previrialization conjecture (Peebles & Groth 1976; Davis & Peebles 1977)

    Migration of giant planets in planetesimal discs

    Full text link
    Planets orbiting a planetesimal circumstellar disc can migrate inward from their initial positions because of dynamical friction between planets and planetesimals. The migration rate depends on the disc mass and on its time evolution. Planets that are embedded in long-lived planetesimal discs, having total mass of 1040.01M10^{-4}-0.01 M_{\odot}, can migrate inward a large distance and can survive only if the inner disc is truncated or because of tidal interaction with the star. In this case the semi-major axis, a, of the planetary orbit is less than 0.1 AU. Orbits with larger aa are obtained for smaller value of the disc mass or for a rapid evolution (depletion) of the disc. This model may explain several of the orbital features of the giant planets that were discovered in last years orbiting nearby stars as well as the metallicity enhancement found in several stars associated with short-period planets.Comment: 21 pages; 6 encapsulated figures. Accepted by MNRA

    Is neck circumference measurement an indicator for abdominal obesity? A pilot study on Turkish Adults

    Get PDF
    Background: Neck circumference (NC) measurement is one of the simple screening measurements which can be used as an index of upper body fat distribution to identify obesity.Objectives: The aim of this study was to determine the relationship between neck circumferences and obesity.Methods:A total 411 volunteer adults participated in this study (174 men, 237 women). A questionnaire which consisted of anthropometric measurements and demographic features was used. Patients with NC ≥37 cm for men and ≥34 cm for women require evaluation of overweight status.Results: The percentages of the men and women with BMI ≥ 25kg/m2 were 55.2% and 27.0% respectively and with high neck circumferences were 85.1% and 38.8%, respectively. The percentages of the men and women with high waist circumference were 31.6% and 79.3%, respectively. In both gender there were positive significant correlations between neck circumference, body weight (men, r=0.576; women, r=0.702; p=0.000), waist circumferences (men, r=0.593; women r=0.667; p=0.000), hip circumferences (men, r=0.568; women, r=0.617; p=0.000) and BMI (men, r=0.587; women, r=0.688; p=0.000).Conclusions: This study indicates that NC was associated with body weight, BMI, waist and hip circumferences and waist/hip ratio for men and women. A significant association was found between NC and conventional overweight and obesity indexes. NC was associated with waist/hip ratio for men and women.Key words: Neck circumference, obesity

    Efficacy of a sensory deterrent and pipe modifications in decreasing entrainment of juvenile green sturgeon (Acipenser medirostris) at unscreened water diversions.

    Get PDF
    Water projects designed to extract fresh water for local urban, industrial and agricultural use throughout rivers and estuaries worldwide have contributed to the fragmentation and degradation of suitable habitat for native fishes. The number of water diversions located throughout the Sacramento-San Joaquin watershed in California's Central Valley exceeds 3300, and the majority of these are unscreened. Many anadromous fish species are susceptible to entrainment into these diversions, potentially impacting population numbers. In the laboratory, juvenile green sturgeon (Acipenser medirostris) have been shown to have high entrainment rates into unscreened diversions compared with those of other native California fish species, which may act as a significant source of mortality for this already-threatened species. Therefore, we tested the efficacy of a sensory deterrent (strobe light) and two structural pipe modifications (terminal pipe plate and upturned pipe configuration) in decreasing the entrainment of juvenile green sturgeon (mean mass ± SEM = 162.9 ± 4.0 g; mean fork length = 39.4 ± 0.3 cm) in a large (>500 kl) outdoor flume fitted with a water-diversion pipe 0.46 m in diameter. While the presence of the strobe light did not affect fish entrainment rates, the terminal pipe plate and upturned pipe modifications significantly decreased the proportion of fish entrained out of the total number tested relative to control conditions (0.13 ± 0.02 and 0.03 ± 0.02 vs. 0.44 ± 0.04, respectively). These data suggest that sensory deterrents using visual stimuli are not an effective means to reduce diversion pipe interactions for green sturgeon, but that structural alterations to diversions can successfully reduce entrainment for this species. Our results are informative for the development of effective management strategies to mitigate the impacts of water diversions on sturgeon populations and suggest that effective restoration strategies that balance agricultural needs with conservation programmes are possible

    Anti-cancer efficiency of natural killer cells differentiated from human adipose tissue-derived mesenchymal stem cells and transfected with miRNA150

    No full text
    Aim: The aim of this study is to investigate the effects of miR150 transfection on NK-like cells differentiated from adipose tissue derived mesenchymal stem cells (AD-MSCs). Methods: NK-like cells were differentiated from AD-MSCs and activated by miR150 transfection. Transfected/non-transfected NK-like cells were characterized by immunohistochemical and RTPCR analyzes. Apoptotic efficiency of the transfected/non-transfected NK-like cells on pancreatic cancer cells PANC1 were determined by TUNEL and RT-PCR. Results: In miR150-transfected cells, the increased expression of NK cell-specific genes such as GZMB, KIR2DL2, CD16, CD56, NKG2D, NKp46 and increased immunoreactivity of NK cell-specific surface marker CD314 (NKG2D) were evident. TUNEL assays showed that NK-like cells with/without transfection induced apoptosis in PANC1 cells in the same manner. The decrease in oncogene expression and the increase in the tumor suppressor gene expression in PANC1 cells upon co-culture with NK-like cells differentiated from AD-MSCs were more prominent following miRNA150 transfection. Conclusion: It was shown in vitro that NK-like cells could be obtained by differentiation from AD-MSCs and their efficiency could be increased via miR150 transfection. The results are encouraging for further clinical studies in improvement of immunotherapeutic approaches for cancer therapy

    Higher P-Wave Dispersion in Migraine Patients with Higher Number of Attacks

    Get PDF
    Objective and Aim. An imbalance of the sympathetic system may explain many of the clinical manifestations of the migraine. We aimed to evaluate P-waves as a reveal of sympathetic system function in migraine patients and healthy controls. Materials and Methods. Thirty-five episodic type of migraine patients (complained of migraine during 5 years or more, BMI < 30 kg/m2) and 30 controls were included in our study. We measured P-wave durations (minimum, maximum, and dispersion) from 12-lead ECG recording during pain-free periods. ECGs were transferred to a personal computer via a scanner and then used for magnification of x400 by Adobe Photoshop software. Results. P-wave durations were found to be similar between migraine patients and controls. Although P WD (P-wave dispersion) was similar, the mean value was higher in migraine subjects. P WD was positively correlated with P max (P < 0.01). Attacks number per month and male gender were the factors related to the P WD (P < 0.01). Conclusions. Many previous studies suggested that increased sympathetic activity may cause an increase in P WD. We found that P WD of migraine patients was higher than controls, and P WD was related to attacks number per month and male gender. Further studies are needed to explain the chronic effects of migraine
    corecore