7,269 research outputs found
Semiclassical Hartree-Fock theory of a rotating Bose-Einstein condensation
In this paper, we investigate the thermodynamic behavior of a rotating
Bose-Einstein condensation with non-zero interatomic interactions
theoretically. The analysis relies on a semiclassical Hartree-Fock
approximation where an integral is performed over the phase space and function
of the grand canonical ensemble is derived. Subsequently, we use this result to
derive several thermodynamic quantities including the condensate fraction,
critical temperature, entropy and heat capacity. Thereby, we investigate the
effect of the rotation rate and interactions parameter on the thermodynamic
behavior. The role of finite size is discussed. Our approach can be extended to
consider the rotating condensate in optical potential
Missing energies at pair creation
Wilson cloud chamber measurements of the separated spectra of positrons and electrons produced by gamma quanta of 6.14 MeV differ considerably from the theoretically predicted spectra by BETHE and HEITLER, but are in good agreement with those of a modified theory of pair creation
Analytic Determination of the Critical Coupling for Oscillators in a Ring
We study a model of coupled oscillators with bidirectional first nearest
neighbours coupling with periodic boundary conditions. We show that a stable
phase-locked solution is decided by the oscillators at the borders between the
major clusters, which merge to form a larger one of all oscillators at the
stage of complete synchronization. We are able to locate these four oscillators
as well as the size of major clusters in the vicinity of the stage of full
synchronization which we show to depend only on the set of initial frequencies.
Using the method presented here, we are able to obtain an analytic form of the
critical coupling, at which the complete synchronization state occurs.Comment: 5 pages and 3 figure
Carminomycin analogue
A novel anthracycline glycoside 2-deoxy-L-fucopyranosyl carminomycinone which is effective for inhibiting the growth of tumors such as leukemia L1210.https://digitalcommons.mtu.edu/patents/1127/thumbnail.jp
Symmetry analysis for steady boundary-layer stagnation-point flow of Rivlin–Ericksen fluid of second grade subject to suction
An analysis for the steady two-dimensional boundary-layer stagnation-point flow of Rivlin–Ericksen fluid of second grade with a uniform suction is carried out via symmetry analysis. By employing Lie-group method to the given system of nonlinear partial differential equations, the symmetries of the equations are determined. Using these symmetries, the solution of the given equations is found. The effect of the viscoelastic parameter k and the suction parameter R on the tangential and normal velocities, temperature profiles, heat transfer coefficient and the wall shear stress, have been studied. Also, the effect of the Prandtl number Pr on the temperature and the heat transfer coefficient has been studied
Synthesis of bis-oxathiaaza[3.3.3]propellanes via nucleophilic addition of (1,ω-alkanediyl)bis(N′-organylthioureas) on dicyanomethylene-1,3-indanedione
A concise and efficient route for synthesis of bis-oxathiaaza[3.3.3]propellanes by reaction of N,N,-N″-(1,ω-alkanediyl)bis-(N″-organylthioureas) with (1,3-dioxo-2,3-dihydro-1H-inden-2- ylidene)propanedinitrile is reported. The structures of the products have been confirmed by using NMR as well as single crystal X-ray analysis for one product. A plausible mechanism for formation of the products is presented.Peer reviewe
Two Coupled Harmonic Oscillators on Non-commutative Plane
We investigate a system of two coupled harmonic oscillators on the
non-commutative plane \RR^2_{\theta} by requiring that the spatial coordinates
do not commute. We show that the system can be diagonalized by a suitable
transformation, i.e. a rotation with a mixing angle \alpha. The obtained
eigenstates as well as the eigenvalues depend on the non-commutativity
parameter \theta. Focusing on the ground state wave function before the
transformation, we calculate the density matrix \rho_0(\theta) and find that
its traces {\rm Tr}(\rho_{0}(\theta)) and {\rm Tr}(\rho_0^2(\theta)) are not
affected by the non-commutativity. Evaluating the Wigner function on
\RR^2_{\theta} confirms this. The uncertainty relation is explicitly determined
and found to depend on \theta. For small values of \theta, the relation is
shifted by a \theta^2 term, which can be interpreted as a quantum correction.
The calculated entropy does not change with respect to the normal case. We
consider the limits \alpha=1 and \alpha={\pi\over 2}. In first case, by
identifying \theta to the squared magnetic length, one can recover basic
features of the Hall system.Comment: 15 pages, 1 figur
Rapidly Progressive IgA Nephropathy in One of a Pair of Identical Twins
Introduction: IgA nephropathy (IgAN) is the most common cause of primary glomerulonephritis worldwide. It was considered a benign condition for many years but long term follow up showed that it might progress to end stage renal disease (ESRD). The cause of primary IgAN is unknown and no consistent genetic abnormalities that predict the development or progression of IgAN have been identified. A variety of observations suggest an as-sociation to an unknown environmental antigen, familial clustering, or infectious agent. The patient presented here is the first report of a child with IgAN in Sudan. Case report: a seven years old boy was referred to our center for further evaluation and management of sudden
onset macroscopic hematuria and renal impairment. He was born after an uneventful pregnancy and breast fed. He developed normally and was healthy before this illness. He had eight siblings who were all healthy, including his identical twin brother. Physical examination and laboratory tests led to the diagnosis of IgAN. The patient was treated with peritoneal dialysis and pulses of methylprednisolone for three consecutive days. He showed a remarkable response and regained normal
renal function. He was then kept on alternate day’s steroids, ACE inhibitors, and Azathioprine. The other twin is being closely monitored.
Conclusion: This report provides an indirect support for the hypothesis that environmental factors play a role in the pathogenesis of IgAN. However, follow up of the currently healthy twin is necessary, since affection with the disease may be expressed at a later time.
Key words: IgA nephropathy, identical twins, macroscopic
hematuri
Doubling the Number of Connected Devices in Narrow-band Internet of Things while Maintaining System Performance: An STC-based Approach
Narrow-band Internet of Things (NB-IoT) is a low-power wide-area network
(LPWAN) method that was first launched by the 3rd generation partnership
project (3GPP) Rel- 13 with the purpose of enabling low-cost, low-power and
wide-area cellular connection for the Internet of Things (IoT). As the demand
for over-the-air services grows and with the number of linked wireless devices
reaching 100 billion, wireless spectrum is becoming scarce, necessitating
creative techniques that can increase the number of connected devices within a
restricted spectral resource in order to satisfy service needs. Consequently,
it is vital that academics develop efficient solutions to fulfill the quality
of service (QoS) criteria of the NB-IoT in the context of 5th generation (5G)
and beyond. This study paves the way for 5G networks and beyond to have
increased capacity and data rate for NB-IoT. Whereas, this article suggests a
method for increasing the number of connected devices by using a technique
known as symbol time compression (STC). The suggested method compresses the
occupied bandwidth of each device without increasing complexity, losing data
throughput or bit error rate (BER) performance. The STC approach is proposed in
the literature to work with the conventional orthogonal frequency division
multiplexing (OFDM) to reduce bandwidth usage by 50% and improve the
peak-to-average power ratio (PAPR). Specifically, An STC-based method is
proposed that exploits the unused bandwidth to double the number of connected
devices while keeping system performance and complexity. Furthermore, the
{\mu}-law companding technique is leveraged to reduce the PAPR of the
transmitted signals. The obtained simulation results reveal that the proposed
approach using the {\mu}-law companding technique increases the transmitted
data by twice and reduces the PAPR by 3.22 dB while maintaining the same
complexity and BER
SENSITIVE SPECTROPHOTOMETRIC ASSAY OF MUSCARINIC RECEPTOR ANTAGONIST TOLTERODINE TARTRATE IN BULK DRUG AND PHARMACEUTICAL FORMULATIONS
Objective: Simple, sensitive, and accurate spectrophotometric methods have been developed for the assay of tolterodine tartrate (TOL) in bulk drugand pharmaceutical formulations.Methods: The proposed methods are based on oxidation reaction of TOL with a known excess of cerium(IV) ammonium sulfate as an oxidizing agentin acid medium followed by determination of unreacted oxidant by adding a fixed amount of dye, e.g., amaranth (AM), rhodamine 6G (Rh6G), andindigo carmine (IC) followed by measuring the absorbance at 520, 530, and 610 nm, respectively. The effect of experimental conditions was studiedand optimized.Results: The Beer's law was obeyed in the concentration ranges of 1.0-10, 1.0-12, and 0.5-9.0 μg/mL using AM, Rh6G, and IC dyes, respectively, witha correlation coefficient ≥0.9995. The calculated molar absorptivity values are 1.868×104, 1.008×104, and 1.623×104 L/mol/cm using AM, Rh6G, andIC dyes, respectively. The limits of detection and quantification were reported. Intraday and interday accuracy and precision of the methods have beenevaluated. No interference was observed from the additives.Conclusion: The proposed methods were successfully applied to the assay of TOL in tablets preparations, and the results were statistically comparedwith those of the reported method by applying Student's t-test and F-test. The reliability of the methods was further ascertained by performingrecovery studies using the standard addition method
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