388 research outputs found

    The survey of the effect of ginger extract on gastric residual volume in mechanically ventilated patients hospitalized in the Intensive Care Units

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    Background and purpose: Delayed gastric emptying in mechanically ventilated patients is common. According to evidences, Ginger can accelerate gastric emptying. This study aimed to determine the effect of ginger extract on gastric residual volume of patients admitted to the Intensive Care Unit. Materials and Methods: In this double-blind randomized controlled clinical trial with before and after schematization, 24 mechanically ventilated patients hospitalized in ICUs were divided into two groups, intervention group (12 patients) and control group (n = 12) after matching for sex and severity of disease. After 48 hours of feeding with a standard gavage solution, the intervention group received 120mg of ginger extract in 4 days and the control group received 5 ml water as placebo in 4 days. The mean residual volume was recorded in the fifth and the sixth days. Data analysis was done with independent and paired T-tests at a significance level of 0.05. Results: The mean residual volume in the first 48 hours was not significantly different between the groups. But after 48 hours of starting treatment, the average of mean and standard deviation of the residual volume in the fifth and sixth days were (24.58±16.81) in intervention group and (108.33±15.09) in control group that according to the Independent T-test showed a significant difference (P <0.0001). Discussion and Conclusion: The result of this study showed that ginger extract reduces gastric residual volume in mechanically ventilated patients hospitalized in intensive care units compared with placebo. © 2013 AENSI Publisher All rights reserved

    Synchronization in Random Geometric Graphs

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    In this paper we study the synchronization properties of random geometric graphs. We show that the onset of synchronization takes place roughly at the same value of the order parameter that a random graph with the same size and average connectivity. However, the dependence of the order parameter with the coupling strength indicates that the fully synchronized state is more easily attained in random graphs. We next focus on the complete synchronized state and show that this state is less stable for random geometric graphs than for other kinds of complex networks. Finally, a rewiring mechanism is proposed as a way to improve the stability of the fully synchronized state as well as to lower the value of the coupling strength at which it is achieved. Our work has important implications for the synchronization of wireless networks, and should provide valuable insights for the development and deployment of more efficient and robust distributed synchronization protocols for these systems.Comment: 5 pages, 4 figure

    PARAMETERS EFFECTS ON CONDUCTION-CONVECTION HEAT TRANSFER IN RECTANGULAR ENCLOSURE SANDWICHED BY FINITE THICKNESS WALLS

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    The effect of wall heat conduction on natural convection heat transfer in cavities has gained attention of many researchers in recent years due to its wide application areas in engineering such that building heating and cooling and thick enclosures , etc . In this work , we consider a two-dimensional numerical study of a rectangle cavity filled with an air with two vertical conductive walls of finite thickness . The enclosure is subjected to horizontal temperature gradient , the vertical boundaries are isothermal at different temperatures whereas the remaining walls are adiabatic .The theoretical study involved the numerical solution of the Navier-stokes and energy equations by using finite difference method . The stream-vorticity formulation was used in the mathematical model . The physical problem depends on five parameters : Rayleigh number (1000&lt;Ra&lt;1000000) , the Prandtl number (Pr=0.7) , the wall to fluid thermal conductivity ratio (0.1&lt;=Kr&lt;=10) , solid to fluid thickness ratio (0.5&lt;=L1/L2&lt;=1.5) , the ratio of (left or right) solid thickness to the height )(D=L1/H=0.5,0.6667,0.75) and the aspect ratio (H/L= 0.5,1,1.5) . The main focus of the study is on examining the effect of conduction in the wall on the natural convection flow .The results are presented to show the effect of these parameters on the heat transfer and fluid flow characteristics

    Eksitonska stanja u kvantnoj točki

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    The exciton binding energies in finite-potential quantum dot discs of GaAs are obtained and the eigenstates and the eigenvalues of the exciton are calculated. We present the exciton binding energy for different values of the disc radius (R) and the disc half-width (L/2). The exciton-state stability for large and small sizes of the dot is discussed. We compare our results with the existing theoretical and experimental results. Our results give good estimates for the optimal quantum dot disc geometry, and represent useful data in studies of the optical properties of quantum dots in nano-scale devices.Izračunali smo energiju vezanja, svojstvena stanja i svojstvene vrijednosti eksitona u kvantnoj točki s konačnim potencijalom. Opisujemo energiju vezanja eksitona za više vrijednosti polumjera (R) i poluširine (L/2) diska. Raspravljamo stabilnost eksitona za male i veće dimenzije diska. Uspoređujemo naše rezultate s poznatim drugim teorijskim i eksperimentalnim rezultatima. Naši rezultati daju dobre ocjene za povoljnu veličinu diska kvantne točke, i predstavljaju korisne podatke za proučavanje optičkih svojstava kvantnih točaka u napravama nano veličine

    Une xpected large benign thymoma on myocardial scintigraphy, a case report

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    Myocardial perfusion imaging (MPI) by 99mTc-sestamibi constitutes a major part of nuclear medicine studies. Incidental detection of extracardiac abnormalities occurs not infrequently. These can include benign and malignant lesions and their detection can be of great value in patient's future. We present a 60 year-old man who underwent MPI to evaluate coronary artery disease as the possible cause of his chest discomfort. The images revealed a large area of intense increased tracer uptake in the antero- inferior mediastinum that further evaluation confirmed to be a benign thymoma. © 2015 The Authors

    Worm Epidemics in Wireless Adhoc Networks

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    A dramatic increase in the number of computing devices with wireless communication capability has resulted in the emergence of a new class of computer worms which specifically target such devices. The most striking feature of these worms is that they do not require Internet connectivity for their propagation but can spread directly from device to device using a short-range radio communication technology, such as WiFi or Bluetooth. In this paper, we develop a new model for epidemic spreading of these worms and investigate their spreading in wireless ad hoc networks via extensive Monte Carlo simulations. Our studies show that the threshold behaviour and dynamics of worm epidemics in these networks are greatly affected by a combination of spatial and temporal correlations which characterize these networks, and are significantly different from the previously studied epidemics in the Internet

    Narrow-band injection seeding of a terahertz frequency quantum cascade laser: Selection and suppression of longitudinal modes

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    A periodically poled lithium niobate (PPLN) crystal with multiple poling periods is used to generate tunable narrow-bandwidth THz pulses for injection seeding a quantum cascade laser (QCL). We demonstrate that longitudinal modes of the quantum cascade laser close to the gain maximum can be selected or suppressed according to the seed spectrum. The QCL emission spectra obtained by electro-optic sampling from the quantum cascade laser, in the most favorable case, shows high selectivity and amplification of the longitudinal modes that overlap the frequency of the narrow-band seed. Proper selection of the narrow-band THz seed from the PPLN crystal discretely tunes the longitudinal mode emission of the quantum cascade laser. Moreover, the THz wave build-up within the laser cavity is studied as a function of the round-trip time. When the seed frequency is outside the maximum of the gain spectrum the laser emission shifts to the preferential longitudinal mode

    Investigation of time-resolved gain dynamics in an injection seeded terahertz quantum cascade laser

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    The evolution of the gain of terahertz quantum cascade laser during injection seeding is probed as a function of time. Oscillations of the gain are commensurate with the variations of the field envelope
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