Magnetic and orbital order in overdoped bilayer manganites

The magnetic and orbital orders for the bilayer manganites in the doping region $0.5 < x <1.0$ have been investigated from a model that incorporates the two $e_g$ orbitals at each Mn site, the inter-orbital Coulomb interaction and lattice distortions. The usual double exchange operates via the $e_g$ orbitals. It is shown that such a model reproduces much of the phase diagram recently obtained for the bilayer systems in this range of doping. The C-type phase with ($\pi,0,\pi$) spin order seen by Ling et al. appears as a natural consequence of the layered geometry and is stabilised by the static distortions of the system. The orbital order is shown to drive the magnetic order while the anisotropic hopping across the $e_g$ orbitals, layered nature of the underlying structure and associated static distortions largely determine the orbital arrangements.Comment: 8 pages, 5 figure

Predator-prey ecosystem with group defence in prey against generalist predator

In this paper, we proposed a population model depicting the dynamics of a prey showing group defence against a generalist predator. The group defence characteristic is represented by Hassell-Varley functional response. We studied the local and global stability and behaviour of the model around the co-existent equilibrium solution. Analysis on Hopf bifurcation and power spectra has also been done. Numerical simulations have been done to confirm the obtained analytical results as well as to validate the proposed model

Applications of Image Reconstruction in NDE

The nondestructive evaluation (NDE) of materials often involves the solution of an inverse problem. It is shown that image reconstruction techniques lead to the direct solution of the 3-D inverse problem when radiographic measurements are made. In particular, it is suggested that the convolve-and-backproject solution to the 3-D divergent ray geometry problem should be useful for NDE. There is also a discussion of the accept-reject criteria appropriate for various classes of defects

Semiclassical Electron Correlation in Density-Matrix Time-Propagation

Lack of memory (locality in time) is a major limitation of almost all present time-dependent density functional approximations. By using semiclassical dynamics to compute correlation effects within a density-matrix functional approach, we incorporate memory, including initial-state dependence, as well as changing occupation numbers, and predict more observables in strong-field applications.Comment: 4.5 pages, 1 figur

Efficient biometric and password based mutual authentication for consumer USB mass storage devices

A Universal Serial Bus (USB) Mass Storage Device (MSD), often termed a USB flash drive, is ubiquitously used to store important information in unencrypted binary format. This low cost consumer device is incredibly popular due to its size, large storage capacity and relatively high transfer speed. However, if the device is lost or stolen an unauthorized person can easily retrieve all the information. Therefore, it is advantageous in many applications to provide security protection so that only authorized users can access the stored information. In order to provide security protection for a USB MSD, this paper proposes a session key agreement protocol after secure user authentication. The main aim of this protocol is to establish session key negotiation through which all the information retrieved, stored and transferred to the USB MSD is encrypted. This paper not only contributes an efficient protocol, but also does not suffer from the forgery attack and the password guessing attack as compared to other protocols in the literature. This paper analyses the security of the proposed protocol through a formal analysis which proves that the information is stored confidentially and is protected offering strong resilience to relevant security attacks. The computational cost and communication cost of the proposed scheme is analyzed and compared to related work to show that the proposed scheme has an improved tradeoff for computational cost, communication cost and security

Time Evolution Of Cyclotron Line of Her X-1; A Detailed StatisticalAnalysis Including New ASTROSAT Data

The cyclotron line feature in the X-ray spectrum of the accretion powered pulsar Her X-1 has been observed and monitored for over three decades. The line energy exhibited a slow secular decline over the period 1995-2014, with a possible (not confirmed) indication of a reversal thereafter. Recent works have shown that the temporal evolution of the line energy may be modelled as a flattening after an earlier decrease until MJD 55400 ($\pm200)$. In this work, we present the results of ASTROSAT observations in the context of earlier data and offer a common interpretation through a detailed study of temporal and flux dependence. We find that the variation of the line energy does not support an upward trend but is consistent with the reported flattening after an earlier decrease until MJD $54487^{+515}_{-469}$.Comment: Accepted in MNRA

Charge order and phase segregation in overdoped bilayer manganites

There have been recent reports of charge ordering around $x=0.5$ in the bilayer manganites. At $x=0.5$, there appears to be a coexistence region of layered A-type antiferromagnetc and charge order. There are also reports of orbital order in this region without any Jahn-Teller effect. Based on physical grounds, this region is investigated from a model that incorporates the two $e_g$ orbitals at each Mn site and a near-neighbour Coulomb repulsion. It is shown that there indeed is both charge and orbital order close to the half-doped region coincident with a layered magnetic structure. Although the orbital order is known to drive the magnetic order, the layered magnetic structure is also favoured in this system by the lack of coherent transport across the planes and the reduced dimensionality of the lattice. The anisotropic hopping across the $e_g$ orbitals and the underlying layered structure largely determine the orbital arrangements in this region, while the charge order is primarily due to the long range interactions.Comment: 6 pages, 6 figure

Which is better for pfannensteil skin incision closure in caesarean section? Interrupted mattress suture or continuous subcuticular suture

Background: Caesarean delivery is one of the most commonly performed operations in obstetrics. Postoperative comfort of the woman largely depends on the method of skin closure. Wound complications from caesarean delivery such as dehiscence or infection cause a significant emotional and economic burden in obstetric care. There are many methods and techniques for skin wound closure in caesarean section. Each technique has its own advantages and disadvantages. The aim and objective of this study was to compare the wound outcomes in Pfannensteil incisions closed with mattress sutures using nonabsorbable suture and subcuticular sutures using absorbable sutures in caesarean deliveries.Methods: It is a prospective observational study done on 216 consecutive pregnant women who were admitted to labor room for elective or emergency caesarean section. Patients undergoing caesarean section with Pfannensteil incision between February 2019 to October 2019 were included in this study. Among 216 women, 108 women had mattress sutures and 108 women had subcuticular sutures for skin wound closure. The primary outcome studied was wound complications including erythema, wound dehiscence, burst abdomen, infection and pain which was studied on postoperative day 3-7. The secondary outcome was assessed at 6 weeks follow-up in terms of pain, cosmetic appearance of scar and patient satisfaction about scar.Results: A total of 216 pregnant women undergoing caesarean section were studied who had similar baseline characteristics and risk factors. However, women with previous caesarean section were more in mattress group. The overall incidence of erythema, surgical site infection, wound dehiscence, resuturing and pain was more in mattress group and was statistically significant. During follow-up at 6 weeks, women with subcuticular sutures had cosmetically better scar and more satisfied with their scars than women with mattress sutures but the pain level was same in both groups.Conclusions: Authors conclude that compared to mattress sutures, subcuticular sutures cause significantly fewer wound complications and pain in postoperative period. Also, subcuticular sutures are associated with cosmetically appealing scars and higher patient satisfaction. But there was no difference in pain level at 6 weeks in both methods of skin closure