1,353 research outputs found
Casimir force in the presence of a magnetodielectric medium
In this article we investigate the Casimir effect in the presence of a medium
by quantizing the Electromagnetic (EM) field in the presence of a
magnetodielectric medium by using the path integral formalism. For a given
medium with definite electric and magnetic susceptibilities, explicit
expressions for the Casimir force are obtained which are in agree with the
original Casimir force between two conducting parallel plates immersed in the
quantum electromagnetic vacuum.Comment: 8 pages, 1 figur
Evaluation of the chemical composition and in vitro antimicrobial activity of Rosmarinus officinalis, Zataria multiflora, Anethum graveolens and Eucalyptus globulus against Streptococcus iniae; the cause of zoonotic disease in farmed fish
There is a growing interest of industry to replace synthetic chemicals by natural products with bioactive properties from plant origin. The purpose of this study was to elucidate the factors affecting antimicrobial effectiveness of essential oils Rosmarinus officinalis, Zataria multiflora, Anethum graveolens and Eucalyptus globulus against food spoilage and pathogenic bacteria, Streptococcus iniae; the cause of zoonotic streptococcosis in fish. Food conservation is based on an intermittent search for foods with a high nutritional quality and microbial stability and it has been reached by the control of the growth/survival of spoiling and pathogen foodborne microorganisms. Based on several reports, fish streptococcosis is currently considered as one of the main limiting factors in the aquaculture industry, due to the significant economic losses (annually more than $150 million) that these infections cause in different cultured fresh and seawater fish species worldwide. The sensitivity of S. iniae to antibacterial activity of the essential oils was determined using well diffusion assays and paper disc diffusion method. The ranges of minimum inhibitory concentration (MIC) of the oils and extracts were 3.9-250 and 7.8-500 ”g/ml and the ranges of minimum bactericidal concentration (MBC) values for the oils and extracts were found to be in the range of 7.8-250 and 15.6-500 ”g/ml, respectively. The essential oils exhibited antibacterial activity against S. iniae. The essential oil of rosemary showed the strongest antimicrobial activity
Characterization of laser propagation through turbulent media by quantifiers based on the wavelet transform: dynamic study
We analyze, within the wavelet theory framework, the wandering over a screen
of the centroid of a laser beam after it has propagated through a time-changing
laboratory-generated turbulence. Following a previous work (Fractals 12 (2004)
223) two quantifiers are used, the Hurst parameter, , and the Normalized
Total Wavelet Entropy, . The temporal evolution of both
quantifiers, obtained from the laser spot data stream is studied and compared.
This allows us to extract information of the stochastic process associated to
the turbulence dynamics.Comment: 11 pages, 3 figures, accepted to be published in Physica
Metal-free tandem rearrangement/lactonization: Access to 3,3-disubstituted benzofuran-2-(3H)-ones
A novel metalâfree synthesis of 3,3âdisubstituted benzofuranâ2(3H)âones from the reaction between αâarylâαâdiazoacetates and triarylboranes is presented. Initially, triarylboranes were successfully investigated in αâarylations of αâdiazoacetates, however in the presence of an orthoâheteroatom substituent the boron enolate intermediate undergoes an intramolecular rearrangement to form a quaternary center. The intermediate cyclizes affording valuable 3,3âdisubstituted benzofuranones in good yield
Finite temperature Casimir effect in the presence of nonlinear dielectrics
Starting from a Lagrangian, electromagnetic field in the presence of a
nonlinear dielectric medium is quantized using path-integral techniques and
correlation functions of different fields are calculated. The susceptibilities
of the nonlinear medium are obtained and their relation to coupling functions
are determined. Finally, the Casimir energy and force in the presence of a
nonlinear medium at finite temperature is calculated.Comment: 16 pages, 0 figure
Entanglement study of the 1D Ising model with Added Dzyaloshinsky-Moriya interaction
We have studied occurrence of quantum phase transition in the one-dimensional
spin-1/2 Ising model with added Dzyaloshinsky-Moriya (DM) interaction from bi-
partite and multi-partite entanglement point of view. Using exact numerical
solutions, we are able to study such systems up to 24 qubits. The minimum of
the entanglement ratio R \tau 2/\tau 1 < 1, as a novel estimator of
QPT, has been used to detect QPT and our calculations have shown that its
minimum took place at the critical point. We have also shown both the
global-entanglement (GE) and multipartite entanglement (ME) are maximal at the
critical point for the Ising chain with added DM interaction. Using matrix
product state approach, we have calculated the tangle and concurrence of the
model and it is able to capture and confirm our numerical experiment result.
Lack of inversion symmetry in the presence of DM interaction stimulated us to
study entanglement of three qubits in symmetric and antisymmetric way which
brings some surprising results.Comment: 18 pages, 9 figures, submitte
Migrant women's experiences of perinatal care in European countries: a systematic review
Background: Across Europe, there are increasing numbers of migrant women who are of childbearing age, pregnant or new mothers. Migrant women face many challenges and have particular needs during the perinatal period. In this age of super-diversity, provision of maternity care which is sensitive to the needs of all factions of our society is paramount to ensure a healthy and forward looking community.
Aim: As part of a larger multicentre study âOperational Refugee and Migrant Maternal Approachâ (ORAMMA)*, this review aimed to evaluate the state of current evidence on migrant womenâs experiences of pregnancy, childbirth and maternity care in their destination country within Europe.
Methods: A systematic search of..
An integrated magneto-optic modulator for cryogenic applications
Superconducting circuits can operate at higher energy efficiencies than their room-temperature counterparts and have the potential to enable large-scale control and readout of quantum computers. However, the required interface with room-temperature electronics creates difficulties in scaling up such cryogenic systems. One option is to use optical fibres as a medium in conjunction with fast optical modulators that can be efficiently driven by electrical signals at low temperatures. However, as superconducting circuits are current operated with low impedances, they interface poorly with conventional electro-optical modulators. Here we report an integrated current-driven modulator that is based on the magneto-optic effect and can operate at temperatures as low as 4âK. The device combines a magneto-optic garnet crystal with a silicon waveguide resonator and integrates an electromagnet to modulate the refractive index of the garnet. The modulator offers data rates of up to 2âGbps with an energy consumption below 4âpJ per bit of transferred information, which could be reduced to less than 50âfJ per bit by replacing dissipative electrodes with superconductors and optimizing the geometric parameters
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