Protection of all nondefective twofold degeneracies by antiunitary symmetries in non-Hermitian systems

Non-Hermitian degeneracies are classified as defective exceptional points (EPs) and nondefective de- generacies. While in defective EPs, both eigenvalues and eigenvectors coalesce, nondefective degeneracies are characterized merely by the emergence of degenerate eigenvalues. It is also known that all degeneracies are either symmetryprotected or accidental. In this paper, I prove that antiunitary symmetries protect all nondefective twofold degeneracies. By developing a 2D non-Hermitian tight-binding model, I have demonstrated that these symmetries comprise various symmetry operations, such as discrete or spatial point-group symmetries and Wick’s rotation in the non-Hermitian parameter space. Introducing these composite symmetries, I present the protection of nondefective degeneracies in various parameter regimes of my model. This work paves the way to stabilizing nondefective degeneracies and offers a new perspective on understanding non-Hermitian band crossings

Dimension Controlled Self-Assembly of Perylene Based Molecules

Recent advances in the self-assembly of highly organized structures of organic semiconducting molecules by controlled non-covalent interactions has opened avenues for creating materials with unique optical and electrical properties. The main focus of this thesis lies in the synthesis and self-assembly of n-type perylene based organic semiconducting molecules into highly organized materials. Perylene based molecules used in this study are perylene diimide (PTCDI, two side-chains), perylene mono imide (m-PTCI, one side-chain), perylene tetracarboxylic acid (PTCA, no side-chain) and tetra-alkali metal salts of PTCA (M 4 -PTCA, no side-chain), which are synthesized from the parent perylene tetracarboxylic dianhydride (PTCDA). The self-assembly of these molecules have been performed using solution processing methods (dispersion, phase-transfer, and phase-transfer at high temperature) by taking advantage of the changes in solubility of the molecules, wherein the molecular interactions are maximized to favorably allow for the formation of highly organized structures. Dimension control (1D, 2D and 3D structures) of self-assembly has been obtained for different perylene based molecules by appropriate design of the molecule followed by controlling the conditions of assembly. In case of PTCDI, a new solution processing method phase-transfer at high temperature (2L-HT) allowed for the controlled formation of extremely long and fluorescent 1D structure. For the m-PTCI molecules the organization by the 2L-HT method was found to result in highly organized, single-crystalline, fluorescent 2D sheets. In the case of perylene based molecules with no side-chains two different methods have been developed for the realization of organized 1D nanostructures. The first method utilizes the chemical conversion of a highly soluble PTCA into 1D nanofibers of the parent insoluble perylene tetracarboxylic anhydride. The second method utilizes the assembly of tetra potassium salt of PTCA (K 4 -PTCA) into 1D nanostructures. Furthermore, it has been demonstrated that these 1D nanostructures can be chemically converted to two different chemical species, both of which still retain the 1D morphological characteristic, though with changes in the size. Various functional self-assembled structures developed in this thesis opens up new avenues to explore structure-property-function relationships and their use in applications such as sensors, electronics and opto-electronic devices

Catch composition and fishing trend of kilka in Iranian part of the Caspian Sea

Population structure of three kilka fishes (Clupeonella spp.), particularly anchovy kilka (C. engrauliformis), in Iranian waters of the Caspian Sea was surveyed in 2003. A total of 3230 biweekly samples were collected from commercially landed kilka at 3 stations in Mazandaran and Guilan provinces. Catch and effort statistics were obtained from the relevant organization. Results showed a great decline in the commercial kilka catch from 95000 tons in 1999 to 15497 tons in 2003. The contribution of anchovy kilka to the total kilka fishery also showed a decline from 71% in 1999 to 52.5% in 2003, while common kilka (C. cultriventris) increased from 13.7% in 1999 to 48.9% in 2003. Fork length range of anchovy kilka showed an increase from 89.2±12mm in 1999 to 100.4±4.9mm in 2003. The age composition of anchovy ranged between 1+ to 7+ years and the dominant group was 5+ years old (age group of 4+ and 5+ comprised 84.6% of population). The K value and L∞ calculated 0.598/year and 110.13 mm respectively. Natural, fishing and total mortality coefficient was estimated 0.69, 0.31 and 1 per year respectively. The results showed a sex ratio of F:M= 68.2:31.8

DEVELOPMENT OF OLMESARTAN MEDOXOMIL-LOADED CHITOSAN MICROPARTICLES: A POTENTIAL STRATEGY TO IMPROVE PHYSICOCHEMICAL AND MICROMERITIC PROPERTIES

Objective: The objective of the present research was to improve physicochemical and micromeritic properties of Olmesartan Medoxomil (OLM), BCS class II antihypertensive drug by loading in Chitosan (CH) microparticles.Methods: The 32 full factorial design was assigned for microparticles prepared by single emulsion technique method using CH, a natural polymer and Glutaraldehyde (GA) as cross linking agent. Developed microparticles were characterized for Micromeritic properties, morphology by Scanning Electron Microscopy (SEM), drug entrapment efficiency, in vitro drug release, and interaction studies Fourier transfer infrared spectroscopy (FTIR) & Differential Scanning Calorimetry (DSC), drug crystallinity study by X-ray diffractometry (XRD) & DSC.Results: Maximum entrapment efficiency was found 61.76% for maximal CH and lower GA concentration. Saturation solubility of microparticles was increased by 13.74 times to that of pure OLM. FTIR showed compatibility between drug and polymer. XRD, DSC and SEM studies confirmed reduction in crystallinity of drug. It led to increase in dissolution profile of the drug and showed 92.61% of drug release in 120 min. These microparticle preparations also helped in improving micromeritic properties like bulk density, tapped density, the angle of repose, Hausner's ratio and Carr's index.Conclusion: The results obtained in the present work demonstrate the potential use of CH to modulate physicochemical and micromeritic properties of OLM especially obtaining significant improvement in dissolution rate. Â

Momentum-dependent relaxation dynamics of the doped repulsive Hubbard model

We study the dynamical behavior of doped electronic systems subject to a global ramp of the repulsive Hubbard interaction. We start with formulating a real-time generalization of the fluctuation-exchange approximation. Implementing this numerically, we investigate the weak-coupling regime of the Hubbard model both in the electron-doped and hole-doped regimes. The results show that both local and nonlocal (momentum-dependent) observables evolve toward a thermal state, although the temperature of the final state depends on the ramp duration and the band filling. We further reveal a momentum-dependent relaxation rate of the distribution function in doped systems and trace back its physical origin to the anisotropic self-energies in the momentum space

Design and Development of Saline Monitoring System Using Load cell

As the world population grows, the need for health care increases. In recent years, progress in medical care has been rapid due to the advancements in the field of sensors, microcontrollers and computers. A major reason for this is the combination of the two important disciplines namely medicine and engineering.                      This paper describes the development of an automatic saline monitoring system using a low cost indigenously developed load cell and GSM (Global system for mobile communication) modem. This enables the doctor or nurse on duty to monitor the saline flow rate from a distance. The Atmel16microcontroller is used for providing co-ordination action.                       Load cell which acts as a weight sensor , used to sense the weight of the bottle.  The detection of saline drop rate is quite faithful. Message about the status of the bottle is transmitted through GSM technology to a distant mobile cell for future actions as well as displayed on LCD display

Bending and free vibration analysis of thick isotropic plates by using exponential shear deformation theory

This paper presents a variationally consistent an exponential shear deformation theory for the bi-directional bending and free vibration analysis of thick plates. The theory presented herein is built upon the classical plate theory. In this displacement-based, refined shear deformation theory, an exponential functions are used in terms of thickness co-ordinate to include the effect of transverse shear deformation and rotary inertia. The number of unknown displacement variables in the proposed theory are same as that in first order shear deformation theory. The transverse shear stress can be obtained directly from the constitutive relations satisfying the shear stress free surface conditions on the top and bottom surfaces of the plate, hence the theory does not require shear correction factor. Governing equations and boundary conditions of the theory are obtained using the dynamic version of principle of virtual work. The simply supported thick isotropic square and rectangular plates are considered for the detailed numerical studies. Results of displacements, stresses and frequencies are compared with those of other refined theories and exact theory to show the efficiency of proposed theory. Results obtained by using proposed theory are found to be agree well with the exact elasticity results. The objective of the paper is to investigate the bending and dynamic response of thick isotropic square and rectangular plates using an exponential shear deformation theory

Second-harmonic generation in the topological multifold semimetal RhSi

Recent experiments in the topological Weyl semimetal TaAs have observed record-breaking second-harmonic generation (SHG), a nonlinear optical response at 2? generated by an incoming light source at ?. However, whether SHG is enhanced in topological semimetals in general is a challenging open question because their band structure entangles the contributions arising from trivial bands and topological band crossings. In this work, we circumvent this problem by studying RhSi, a chiral topological semimetal with a simple band structure with topological multifold fermions close to the Fermi energy. We measure SHG in a wide frequency window, ? [0.27,1.5]eV and, using first-principles calculations, we establish that, due to their linear dispersion, the contribution of multifold fermions to SHG is subdominant as compared with other regions in the Brillouin zone. Our calculations suggest that parts of the bands where the dispersion is relatively flat contribute significantly to SHG. As a whole, our results suggest avenues to enhance SHG responses. © 2022 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Open access publication funded by the Max Planck Society

Comparing predictions made by a prediction model, clinical score, and physicians Pediatric asthma exacerbations in the emergency department

Background: Asthma exacerbations are one of the most common medical reasons for children to be brought to the hospital emergency department (ED). Various prediction models have been proposed to support diagnosis of exacerbations and evaluation of their severity. Objectives: First, to evaluate prediction models constructed from data using machine learning techniques and to select the best performing model. Second, to compare predictions from the selected model with predictions from the Pediatric Respiratory Assessment Measure (PRAM) score, and predictions made by ED physicians. Design: A two-phase study conducted in the ED of an academic pediatric hospital. In phase 1 data collected prospectively using paper forms was used to construct and evaluate five prediction models, and the best performing model was selected. In phase 2, data collected prospectively using a mobile system was used to compare the predictions of the selected prediction model with those from PRAM and ED physicians. Measurements: Area under the receiver operating characteristic curve and accuracy in phase 1; accuracy, sensitivity, specificity, positive and negative predictive values in phase 2. Results: In phase 1 prediction models were derived from a data set of 240 patients and evaluated using 10-fold cross validation. A naive Bayes (NB) model demonstrated the best performance and it was selected for phase 2. Evaluation in phase 2 was conducted on data from 82 patients. Predictions made by the NB model were less accurate than the PRAM score and physicians (accuracy of 70.7%, 73.2% and 78.0% respectively), however, according to McNemar’s test it is not possible to conclude that the differences between predictions are statistically significant. Conclusion: Both the PRAM score and the NB model were less accurate than physicians. The NB model can handle incomplete patient data and as such may complement the PRAM score. However, it requires further research to improve its accuracy