Self-consistent Theory For Magnetic Properties In High-temperature Superconductors

It is now widely known that the new high-temperature superconductors are antiferromagnetic insulators in their normal state. Experimental results indicate that layered cuprates such as {dollar}La\sb{lcub}2-x{rcub}Sr\sb{lcub}x{rcub}CuO\sb4{dollar} and {dollar}YBa\sb2Cu\sb3O\sb{lcub}6+x{rcub}{dollar} go from antiferromagnetic to superconducting state as x changes in the stoichiometry with doping. This suggests a possible correlation between the properties of antiferromagnetism and superconductivity in these materials. Also, the magnetic properties in the normal state such as Neel temperature, its dependence on doping, the sublattice magnetization etc. have an unusual behaviour which is not yet fully understood. The existing theories are not able to explain these magnetic properties. The aim of this thesis, therefore, is to understand the magnetic properties of these compounds in the antiferromagnetic insulating state.;We have developed a theory which takes into account the antiferromagnetic correlations present within the CuO{dollar}\sb2{dollar} layers and also the weak but finite interlayer coupling between these CuO{dollar}\sb2{dollar} planes. Our theory is based on the Green\u27s function approach by which we have obtained an expression for the Neel temperature, its doping dependence, the sublattice magnetization, the magnetic susceptibility and the magnetic correlation length. We have obtained self-consistent expressions for sublattice magnetization and susceptibility. We have found analytical expressions for some of these magnetic properties which would prove extremely helpful to the experimentalists. We have compared our theoretical results to the experimental result for doping dependent Neel temperature, sublattice magnetization, magnetic susceptibility and the magnetic correlation length. It is shown that the theory gives good agreement with experiments. We have also developed a new method by using the spectral function of the spin waves to calculate the magnetic susceptibility in the presence of an external magnetic field. It is shown that at high enough temperatures the results obtained are quite consistent with the experimental results. It is shown that the magnetic properties have a crossover from 3-D to quasi-2D behaviour with temperature and the ratio of inter to intraplanar couplings in these materials.;Our theory gives some very significant predictions. It has shown a logarithmic behaviour for the Neel temperature and a square root of temperature behaviour for the sublattice magnetization near the Neel temperature. It also predicts an exponential behaviour for the magnetic correlation length and its evaluation gives good agreement with other theoretical and simulation results. A comparative analysis of our results with those of spin-wave theory and other theories is also presented

Cilindrično-simetrični nehomogeni kozmološki modeli s magnetskim poljem, strunama, perfektnom raspodjelom fluida i promjenljivom permeabilnošću

A new class of cylindrically-symmetric magnetized inhomogeneous perfect-fluid string cosmological models with variable magnetic permeability is investigated. We assume that F12 is the only non-vanishing component of the electromagnetic field tensor Fij . The Maxwell’s equations show that F12 is the function of x alone, whereas the magnetic permeability ¯µ may be the function of both x and t. To get the deterministic solution, it has been assumed that the metric coefficients are separable in the form as A = f(x)ℓ(t), B = g(x)k(t), C = g(x)ν(t). Also, the Einstein field equations have been solved with string source in which magnetic field is absent. Some physical and geometric aspects of the models in the presence and absence of magnetic field are discussed.Istražujemo novu vrstu cilindrično-simetričnih nehomogenih kozmoloških modela s magnetskim poljem, perfektnim fluidom, strunama i promjenljivom permeabilnošću. Pretpostavljamo da je F12 jedina neiščezavajuća sastavnica tenzora elektromagnetskog polja Fij . Maxwellove jednadžbe daju da je F12 funkcija samo x, dok magnetska permeabilnost može ovisiti o x i o t. Radi postizanja određenosti rješenja, pretpostavili smo separabilne metričke koeficijente u obliku A = f(x)ℓ(t), B = g(x)k(t), C = g(x)ν(t). Također smo riješili Einsteinove jednadžbe polja sa strunskim izvorom bez prisustva magnetskog polja. Raspravljamo neka fizička i geometrijska svojstva modela u prisustvu i bez magnetskog polja

Clinical profile and complication of nephrotic syndrome in a tertiary health care center in central India

Background: Nephrotic syndrome (NS) is a common renal disease that is characterized by episodes of relapses and remissions, with variations in the outcome. It is an important cause of chronic renal disease. Objective: The objective of the study was to access the clinical presentation, investigation profile, associated complication, and therapeutic response in children with NS. Materials and Methods: This prospective observational study was conducted from March 2017 to June 2018 in the department of pediatrics of a tertiary care institution of Central India. A total of 107 children diagnosed with NS were included in the study. Detailed information on age, sex, age at first episode, presenting complaint, history of presenting illness, social, and family history was taken. Detailed general physical examination, systemic examination, investigation profile, and response to management were recorded on a pro forma and correlated statistically. Results: of 107 cases of NS, the most common age group was 5–7 years (54.2%). There were 73 (68.2%) males and 34 (31.7%) females with a male-to-female ratio of 2.1:1. It was found that 39 (36.4%) subjects were newly diagnosed and 68 (63.6%) were relapse cases. A total of 95 (88.8%) patients were steroid-sensitive while 12 (11.2%) had initial steroid resistance NS. Conclusion: In our study, clinical presentation and response to treatment in cases with NS did not differ significantly from other studies

Experimental Study of Hydroformed Al6061T4 Elliptical Tube Samples under Different Internal Pressures

In order to achieve crack free elliptical shape under controlled conditions, an experimental set-up was designed and fabricated. This setup consists of three hydraulic cylinders, an intensifier, a hydraulic power pack, storage tanks, forming die, and all parts are controlled by a Programmable Logic Controller (PLC) system. The elliptical samples can be achieved through proper control of internal pressure and axial force with proper sealing. Experimental work has been carried out with different magnitudes of internal pressure and constrained conditions of axial force. Initially die of elliptical shape has been designed and modeled in Abaqus to successfully achieve the particular shape of the Al6061T4 tube under different internal pressure. The fabricated tube hydroforming machine set-up is highly effective for forming 0.5 mm-2 mm thick Al6061T4 alloy tube samples. The Experimental test has been carried out at 12.7 mm outer diameter, 175 mm length and 0.5 mm thick Al6061T4 samples. Bulge height parameters measured at different points of regular distance gap on the axial direction of the tube length and corner radius found at different pressures range of the samples are plotted under different internal pressures. Samples having an 18.7 mm major elliptical bulge were achieved during the experiment. The experimental data was validated by simulation results

Probabilistic Quantum Teleportation via 3-Qubit Non-Maximally Entangled GHZ State by Repeated Generalized Measurements

We propose a scheme of repeated generalized Bell state measurement (GBSM) for probabilistic quantum teleportation of single qubit state of a particle (say, 0) using 3-qubit non-maximally entangled (NME) GHZ state as a quantum channel. Alice keeps two qubits (say, 1 and 2) of the 3-qubit resource and the third qubit (say, 3) goes to Bob. Initially, Alice performs GBSM on qubits 0 and 1 which may lead to either success or failure. On obtaining success, Alice performs projective measurement on qubit 2 in the eigen basis of $\sigma_{x}$. Both these measurement outcomes are communicated to Bob classically, which helps him to perform a suitable unitary transformation on qubit 3 to recover the information state. On the other hand, if failure is obtained, the next attempt of GBSM is performed on qubits 0 and 2. This process of repeating GBSM on alternate pair of qubits may continue until perfect teleportation with unit fidelity is achieved. We have obtained analytical expressions for success probability up to three repetitions of GBSM. The success probability is shown to be a polynomial function of bipartite concurrence of the NME resource. The variation of success probability with the bipartite concurrence has been plotted which shows the convergence of success probability to unity with GBSM repetitions.Comment: 11 pages, 5figure

Prevalence and Associated Risk Factors of Hypertension: A Cross-Sectional Study in Urban Varanasi

Hypertension is a major public health problem and important area of research due to its high prevalence and being major risk factor for cardiovascular diseases and other complications. Objectives. (1) To assess the prevalence of hypertension and its associated factors and (2) to estimate awareness, treatment, and adequacy of control of hypertension among study subjects. Methods and Materials. A community based cross-sectional study with multistage sampling design was conducted among urban population of Varanasi. A modified WHO STEPS interview schedule on 640 study subjects aged 25–64 years was used. Results. The prevalence of hypertension was 32.9% (male: 40.9%, female: 26.0%). Mean systolic and diastolic BP were 124.25 ± 15.05 mmHg and 83.45 ± 9.49 mmHg, respectively. Higher odds of being hypertensive were found in male subjects, eldest age group, married subjects, subjects of upper socioeconomic status, illiterate subjects, and retired subjects. Tobacco and alcohol consumption, overweight, obesity, and abdominal obesity were also associated with hypertension. Out of the total hypertensive 211 subjects, only 81 (38.4%) were aware about their hypertension status; out of those, 57 (70.4%) were seeking treatment and 20 (35.08%) had their blood pressure adequately controlled. Conclusion. Around one-third of the subjects were hypertensive and half of the study subjects were prehypertensive in this area. The awareness, treatment, and control of high blood pressure were also very low