1,257 research outputs found
Experimental high-dimensional two-photon entanglement and violations of generalised Bell inequalities
Quantum entanglement plays a vital role in many quantum information and
communication tasks. Entangled states of higher dimensional systems are of
great interest due to the extended possibilities they provide. For example,
they allow the realisation of new types of quantum information schemes that can
offer higher information-density coding and greater resilience to errors than
can be achieved with entangled two-dimensional systems. Closing the detection
loophole in Bell test experiments is also more experimentally feasible when
higher dimensional entangled systems are used. We have measured previously
untested correlations between two photons to experimentally demonstrate
high-dimensional entangled states. We obtain violations of Bell-type
inequalities generalised to d-dimensional systems with up to d = 12.
Furthermore, the violations are strong enough to indicate genuine
11-dimensional entanglement. Our experiments use photons entangled in orbital
angular momentum (OAM), generated through spontaneous parametric
down-conversion (SPDC), and manipulated using computer controlled holograms
Heat and Mass Transfer in Micropolar Model for Blood Flow Through a Stenotic Tapered Artery
Heat and mass transfer in blood flow through a tapered artery with mild stenosis is examined. The blood is considered to be an incompressible, micropolar fluid flowing through a vessel with nonsymmetric axial and symmetric radial axes. The geometry of the model takes into account the shape parameter, tapered angle and height of the stenosis.The variation in the shape parameter is used to describe the changes in the axial shape of the stenosis in the artery. The governing equations for the model, comprising the continuity, momentum, energy, and mass transfer equations are transformed and simplified under the assumption of mild stenosis. Analytical solutions for the equations are obtained. The effect of different parameters on temperature, concentration, velocity, resistance, shear stress, pressure drop, Nusselt number, and Sherwood number are presented in graphical form, analysed and discussed. It is discovered that the blood temperature increases as micropolar spin parameter or the particle size increases. Also, its concentration is slowed down with an increase in the micropolar parameter or coupling number. The temperature in the converging artery is higher than that of diverging artery when compared under the same conditions
Decline in adolescent treatment admissions for methamphetamine use in Cape Town
Background and objectives. The purpose of this report is to describe the changing trends in adolescent treatment admissions for methamphetamine in Cape Town, and to discuss possible implications.Method. Data were collected on admissions for drug abuse treatment through a regular monitoring system involving drug treatment centres and programmes in Cape Town, every 6 months as part of the South African Community Epidemiology Network on Drug Use (SACENDU). A one-page form was completed by treatment centre personnel for each patient to collect demographic and substance abuse data.Results. The results indicate that between 2004 and 2006, a significant increase in the proportion of adolescent treatment admissions for methamphetamine abuse occurred, while a significant decrease occurred between 2006 and 2011.Conclusions. The initial increase in adolescent treatment admissions for methamphetamine abuse from 2004 to 2006, and subsequent decrease between 2006 and 2011, may suggest a change in methamphetamine abuse patterns among adolescents in Cape Town
Knowledge and utilization of non-pneumatic anti-shock garment for the management of postpartum hemorrhage among Midwives in government hospitals in Ogun State, Nigeria
Objective: To assess the knowledge and determine the level of utilization of Non-Pneumatic Anti-Shock Garment (NASG) for the management of PPH among Midwives.
Method: The study employed a descriptive cross-sectional study design, using a validated self-administered questionnaire. A total of 198 randomly selected midwives across three health facilities in Ogun State participated in the study. A 10-point knowledge scale was used to assess the knowledge of midwives on NASG. Descriptive statistics were used to determine the level of utilization of NASG among midwives, while Chi-square statistics were used to determine the relationship between the dependent and independent variables of interest at p<0.05 level of significance.
Results: Most (88.9%) of the respondents were female with a mean age of 40.2±5.6years. Most (48.5%) had a BNS degree. The majority (74.7%) of the respondents were aware of NASG. Close to a half (49.3%) of the respondents had fair knowledge scores, 34.5% had good knowledge scores, while 16.2% had poor knowledge scores. Only 22.7% of the respondents had ever used NASG in the management of PPH; 77.3% never used it before. Also, 67.2% of the respondents reported NASG was not available in their facilities. There was a significant influence of knowledge of NASG on the utilization among midwives (X2=37.151, P<0.05, df=2).
Conclusion: This study demonstrated that midwives in healthcare facilities were aware, but did not have good knowledge of NASG. The utilization of the garment for the management of PPH was also very poor, probably due to suboptimal knowledge and non-availability of the garment
Dynamic Response of Two Viscoelastically Connected Rayleigh Beams Subjected to Concentrated Moving Load
A theory concerning the dynamic response of two identical simply supported Rayleigh beams viscoelastically connected together by a flexible core and traversed by a concentrated moving load is developed in this paper. The solution technique employed is based on finite Fourier and Laplace integral transformations. It is observed that the maximum amplitude of the deflection of the upper beam increases with an increase in the value of the rotatory inertia while the maximum amplitude of deflection of the lower beam decreases with increasing values of rotatory inerti
Quantum measurements of atoms using cavity QED
Generalized quantum measurements are an important extension of projective or
von Neumann measurements, in that they can be used to describe any measurement
that can be implemented on a quantum system. We describe how to realize two
non-standard quantum measurements using cavity quantum electrodynamics (QED).
The first measurement optimally and unabmiguously distinguishes between two
non-orthogonal quantum states. The second example is a measurement that
demonstrates superadditive quantum coding gain. The experimental tools used are
single-atom unitary operations effected by Ramsey pulses and two-atom
Tavis-Cummings interactions. We show how the superadditive quantum coding gain
is affected by errors in the field-ionisation detection of atoms, and that even
with rather high levels of experimental imperfections, a reasonable amount of
superadditivity can still be seen. To date, these types of measurement have
only been realized on photons. It would be of great interest to have
realizations using other physical systems. This is for fundamental reasons, but
also since quantum coding gain in general increases with code word length, and
a realization using atoms could be more easily scaled than existing
realizations using photons.Comment: 10 pages, 5 figure
Heat And Mass Transfer Of Magnetohydrodynamic (Mhd) And Dissipative Fluid Flow Past A Moving Vertical Porous Plate With Variable Suction
An investigation was carried out on the radiation effect on unsteady heat and mass transfer of MHD and dissipative fluid flow past a moving vertical porous plate with variable suction in the presence of heat generation and chemical reaction. The dimensionless governing equations for this model were solved analytically using perturbation method. The effects of various parameters on the velocity, temperature and concentration fields as well as the Coefficient of skin-friction, Nusselt number and Sherwood number were presented graphically and in tabulated forms. Keywords: Chemical reaction, Unsteady, Porous medium, MHD, Radiation, Mass transfer and Heat sourc
A Positive-Weight Next-to-Leading-Order Monte Carlo for e+e- Annihilation to Hadrons
We apply the positive-weight Monte Carlo method of Nason for simulating QCD
processes accurate to Next-To-Leading Order to the case of e+e- annihilation to
hadrons. The method entails the generation of the hardest gluon emission first
and then subsequently adding a `truncated' shower before the emission. We have
interfaced our result to the Herwig++ shower Monte Carlo program and obtained
better results than those obtained with Herwig++ at leading order with a matrix
element correction.Comment: 21 pages, 11 figures, 2 tables Reason for replacement: minor
corrections, typos and 1 changed referenc
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A positive-weight next-to-leading-order Monte Carlo for e<sup>+</sup>e <sup>-</sup> annihilation to hadrons
We apply the positive-weight Monte Carlo method of Nason for simulating QCD
processes accurate to Next-To-Leading Order to the case of e+e- annihilation to
hadrons. The method entails the generation of the hardest gluon emission first
and then subsequently adding a `truncated' shower before the emission. We have
interfaced our result to the Herwig++ shower Monte Carlo program and obtained
better results than those obtained with Herwig++ at leading order with a matrix
element correction
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