407 research outputs found
An exploratory study of goods and services tax awareness in Malaysia
Tax has been recognized as one of the main sources of governments’ income. Goods and Services Tax (GST) is an example of tax that contributes to the governments’ income. This tax has been implemented in many countries such as Canada, Australia and New Zealand. GST is a tax imposed on
the sale of goods and services. In recent years, this issue on GST has been raised by the Malaysian Government as an approach to reduce its deficit. However, the Malaysian Government is still finding the right time to implement GST as they are still conducting studies on the social impact of GST. This study attempts to investigate Malaysian awareness towards the upcoming of GST implementation
Entanglement genesis by ancilla-based parity measurement in 2D circuit QED
We present an indirect two-qubit parity meter in planar circuit quantum
electrodynamics, realized by discrete interaction with an ancilla and a
subsequent projective ancilla measurement with a dedicated, dispersively
coupled resonator. Quantum process tomography and successful entanglement by
measurement demonstrate that the meter is intrinsically quantum non-demolition.
Separate interaction and measurement steps allow commencing subsequent data
qubit operations in parallel with ancilla measurement, offering time savings
over continuous schemes.Comment: 5 pages, 4 figures; supplemental material with 5 figure
Radio-Frequency Single-Electron Refrigerator
We propose a cyclic refrigeration principle based on mesoscopic electron
transport. Synchronous sequential tunnelling of electrons in a
Coulomb-blockaded device, a normal metal-superconductor single-electron box,
results in a cooling power of at temperature
over a wide range of cycle frequencies . Electrostatic work, done by the
gate voltage source, removes heat from the Coulomb island with an efficiency of
, where is the superconducting gap. The
performance is not affected significantly by non-idealities, for instance by
offset charges. We propose ways of characterizing the system and of its
practical implementation.Comment: 5 pages, 4 figures; corrected typos, language improve
Two-junction superconductor-normal metal single-electron trap in a combined on-chip RC environment
Dissipative properties of the electromagnetic environment as well as on-chip
RC filtering are shown to suppress random state switchings in the two-junction
superconductor(S) - normal metal(N) electron trap. In our experiments, a local
high-ohmic resistor increased the hold time of the trap by up to two orders of
magnitude. A strong effect of on-chip noise filtering was observed for
different on-chip geometries. The obtained results are promising for
realization of the current standard on the basis of the S-N hybrid turnstile.Comment: 4 pages 3 figures LT2
CFD software applications for transcritical free surface flow
Flows in rivers, floodplains and coastal zones are very complex due to uneven bottom topography and irregular boundaries of the flow domain. In particular, when the flow shows strong gradients in water depth and velocity it is very difficult to predict, with accuracy, flow characteristics such as water profiles in all points of the domain. Traditional approaches solve shallow-water flow equations, known as Saint-Venant equations, when one or two dimension solutions can be adequate for obtaining most of the important flow characteristics. However, complex situations can require solving Navier-Stokes equations. In these cases, a two-phase flow problem must be solved and, as water profiles are not known in advance, only a numerical approach can be used to obtain approximate solutions. In addition, flow can be subcritical, supercritical or in a mixed-flow regime. These flow characteristics and complex geometries can make the use of in-house developed software difficult. The arrival of high performance computers and commercial software packages offers new possibilities in the field of numerical hydraulics. However, commercial software packages should be tested on some specific cases; so that these can be used with confidence. In this paper we solve, several cases of free surface flow that consider subcritical, supercritical, critical, oscillatory depth profiles and hydraulic jumps using a commercial package, CFX™. Most of these cases were proposed as benchmark solutions by MacDonald et al. (1997) for non-prismatic cross section, non-uniform bed slope and transition between subcritical and supercritical flow. Hydraulic jump cases consist of experimental data of hydraulics jumps obtained by Gharangik & Chaudhry (1991) for incident flow with Froude numbers of 2.3 and 4.23. In all simulated cases flow was described using a homogeneous model for each phase of the flow. Turbulence was modeled by using the well-known k-ε model. In addition, sensitivity to turbulence level in the entrance of flow domain was done to assure independence of results with this variable. Experimental facilities were properly represented in order to assure exact correspondence between boundary conditions of the model and the actual facility. Results obtained with CFX™ show excellent agreement with analytical solutions, for subcritical, supercritical, transitional and hydraulic jump cases. Special care with grid selection and entrance boundary condition is crucial to simulate with accuracy these types of flows. In particular, when a proper structured mesh is used, quality results are highly improved. Finally, results show to be insensitive to entrance turbulence condition
Equivalent qubit dynamics under classical and quantum noise
We study the dynamics of quantum systems under classical and quantum noise,
focusing on decoherence in qubit systems. Classical noise is described by a
random process leading to a stochastic temporal evolution of a closed quantum
system, whereas quantum noise originates from the coupling of the microscopic
quantum system to its macroscopic environment. We derive deterministic master
equations describing the average evolution of the quantum system under
classical continuous-time Markovian noise and two sets of master equations
under quantum noise. Strikingly, these three equations of motion are shown to
be equivalent in the case of classical random telegraph noise and proper
quantum environments. Hence fully quantum-mechanical models within the Born
approximation can be mapped to a quantum system under classical noise.
Furthermore, we apply the derived equations together with pulse optimization
techniques to achieve high-fidelity one-qubit operations under random telegraph
noise, and hence fight decoherence in these systems of great practical
interest.Comment: 5 pages, 2 figures; converted to PRA format, added Fig. 2, corrected
typo
Azithromycin effectiveness against intracellular infections of Francisella
<p>Abstract</p> <p>Background</p> <p>Macrolide antibiotics are commonly administered for bacterial respiratory illnesses. Azithromycin (Az) is especially noted for extremely high intracellular concentrations achieved within macrophages which is far greater than the serum concentration. Clinical strains of Type B <it>Francisella </it>(<it>F.</it>) <it>tularensis </it>have been reported to be resistant to Az, however our laboratory <it>Francisella </it>strains were found to be sensitive. We hypothesized that different strains/species of <it>Francisella </it>(including Type A) may have different susceptibilities to Az, a widely used and well-tolerated antibiotic.</p> <p>Results</p> <p><it>In vitro </it>susceptibility testing of Az confirmed that <it>F. tularensis subsp. holarctica </it>Live Vaccine Strain (LVS) (Type B) was not sensitive while <it>F. philomiragia, F. novicida</it>, and Type A <it>F. tularensis </it>(NIH B38 and Schu S4 strain) were susceptible. In J774A.1 mouse macrophage cells infected with <it>F. philomiragia, F. novicida</it>, and <it>F. tularensis </it>LVS, 5 μg/ml Az applied extracellularly eliminated intracellular <it>Francisella </it>infections. A concentration of 25 μg/ml Az was required for <it>Francisella-</it>infected A549 human lung epithelial cells, suggesting that macrophages are more effective at concentrating Az than epithelial cells. Mutants of RND efflux components (<it>tolC </it>and <it>ftlC</it>) in <it>F. novicida </it>demonstrated less sensitivity to Az by MIC than the parental strain, but the <it>tolC </it>disc-inhibition assay demonstrated increased sensitivity, indicating a complex role for the outer-membrane transporter. Mutants of <it>acrA </it>and <it>acrB </it>mutants were less sensitive to Az than the parental strain, suggesting that AcrAB is not critical for the efflux of Az in <it>F. novicida</it>. In contrast, <it>F. tularensis </it>Schu S4 mutants Δ<it>acrB </it>and Δ<it>acrA </it>were more sensitive than the parental strain, indicating that the AcrAB may be important for Az efflux in <it>F. tularensis </it>Schu S4. <it>F. novicida </it>LPS O-antigen mutants (<it>wbtN, wbtE, wbtQ </it>and <it>wbtA</it>) were found to be less sensitive <it>in vitro </it>to Az compared to the wild-type. Az treatment prolonged the survival of <it>Galleria </it>(<it>G</it>.) <it>mellonella </it>infected with <it>Francisella</it>.</p> <p>Conclusion</p> <p>These studies demonstrate that Type A <it>Francisella </it>strains, as well as <it>F. novicida </it>and <it>F. philomiragia</it>, are sensitive to Az <it>in vitro. Francisella </it>LPS and the RND efflux pump may play a role in Az sensitivity. Az also has antimicrobial activity against intracellular <it>Francisella</it>, suggesting that the intracellular concentration of Az is high enough to be effective against multiple strains/species of <it>Francisella</it>, especially in macrophages. Az treatment prolonged survival an <it>in vivo </it>model of <it>Francisella-</it>infection.</p
Vanishing quasiparticle density in a hybrid Al/Cu/Al single-electron transistor
The achievable fidelity of many nanoelectronic devices based on
superconducting aluminum is limited by either the density of residual
nonequilibrium quasiparticles n_qp or the density of quasiparticle states in
the gap, characterized by Dynes parameter \gamma. We infer upper bounds n_qp <
0.033 um^-3 and \gamma < 1.6*10^-7 from transport measurements performed on
Al/AlOx/Cu single-electron transistors, improving previous results by an order
of magnitude. Owing to efficient microwave shielding and quasiparticle
relaxation, typical number of quasiparticles in the superconducting leads is
zero.Comment: 5 pages, 3 figures; updated to revised version that was accepted for
publication, contains data from a reference sample without qp trap
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