Effect of Y substitution on the structural and magnetic properties of Dy1-xYxCo5 compounds

Structural and magnetization studies were carried out on Dy1-xYxCo5 [x = 0, 0.2, 0.4, 0.6, 0.8, 1] compounds which crystallize in the hexagonal CaCu5-type structure. Lattice parameters and unit-cell volume increase with Y concentration. Large thermomagnetic irreversibility between the field-cooled and the zero-field cooled magnetization data has been observed in all the compounds, which has been attributed to the domain wall pinning effect. Temperature dependence of magnetization data shows that except DyCo5 and YCo5, all the compounds show spin reorientation transitions in the range of 5-300 K. The spin reorientation temperature decreases from 266 K for x=0.2 to 100 K for x=0.8. Powder x-ray diffractograms of the magnetically aligned samples show that DyCo5 has planar anisotropy at room temperature whereas all the other compounds possess axial anisotropy. The spin reorientation transition has been attributed to a change in the easy magnetization direction from the ab-plane to the c-axis, as the temperature is increased. The anisotropy field and the first order anisotropy constant are found to be quite high in all the compounds except DyCo5. The magnetic properties have been explained by taking into account the variations in contributions arising from the rare earth and transition metal sublattices.Comment: 12 pages, 7 figure

Allocative Efficiency of Resource use on Beekeeping in Chitwan District of Nepal

Agriculture is facing with increasing pollinators decline all over the world affecting the functioning of regulatory and production service of pollination in adverse manner. Study on ways to conserve pollinating agents like bee is crucial in modern intensive agriculture. In this context a study was conducted to estimate the productivity and resource use efficiency of bee keeping in Chitwan district of Nepal. The study used data collected from randomly selected 48 bee keepers using face to face interview technique in the year 2014. Descriptive statistics, gross margin analysis, benefit cost analysis and multiple regression analysis using Cob-Douglas form were employed to achieve study objectives. It was found that farmers were rearing honey bee on an average of about 34 hives per farm with annual productivity of bee products equivalent to 36 Kg honey per hive. Gross margin of beekeeping in the research area was found to be NRs. 3111.55 per hive with undiscounted benefit cost ratio of 1.71. Human labour use, expenditure on sugar, drugs and comb foundation and; migration cost were significantly contributing to the productivity of beekeeping and were required to increase their use by 39%, 34% and 74%, respectively to achieve optimum profit. It was suggested to increase the level of all variable inputs through loan, subsidy and insurance to promote beekeeping enterprise in the study area for ensuring optimum profit to farmers and conservation of the most important agent of pollination

Quantum state estimation and large deviations

In this paper we propose a method to estimate the density matrix \rho of a d-level quantum system by measurements on the N-fold system. The scheme is based on covariant observables and representation theory of unitary groups and it extends previous results concerning the estimation of the spectrum of \rho. We show that it is consistent (i.e. the original input state \rho is recovered with certainty if N \to \infty), analyze its large deviation behavior, and calculate explicitly the corresponding rate function which describes the exponential decrease of error probabilities in the limit N \to \infty. Finally we discuss the question whether the proposed scheme provides the fastest possible decay of error probabilities.Comment: LaTex2e, 40 pages, 2 figures. Substantial changes in Section 4: one new subsection (4.1) and another (4.2 was 4.1 in the previous version) completely rewritten. Minor changes in Sect. 2 and 3. Typos corrected. References added. Accepted for publication in Rev. Math. Phy

Оптимизация нормированной переходной функции линейной цепи, описываемой характеристическим уравнением 4-го порядка

Определение параметров усилительной схемы, обеспечивающих наилучшую форму переходной характеристики, является одной из наиболее сложных задач усилительной техники. При наличии нескольких варьируемых параметров, т. е. при характеристических уравнениях выше второй степени, задача значительно усложняется и случайным варьированием или машинным перебором сочетаний параметров решить ее чрезвычайно трудно. С целью значительного сокращения усилий и времени, затрачиваемых на решение подобных задач, разработаны алгоритм и методика определения с помощью цифровых ЭВМ оптимальных значений коэффициентов коррекции переходных функций линейных целей, описываемых характеристическими уравнениями 2-й и 4-й степеней, при заданных значениях первого и второго выбросов. Приведены графики, иллюстрирующие ре­зультаты вычислений

Модифицирование матриксов из поли-L-молочной кислоты импульсным сильноточным электронным пучком

We describe the synthesis, characterisation and surface-modification of magnetic narroparticles and a poly(N-isopropylacrylamide) microgel, followed by the assembly and characterisation of magnetic nanoparticles on the microgel. To facilitate this deposition, the surface of the microgel is first modified via the layer-by-layer assembly of polyelectrolytes. One advantage of this concept is that it allows an independent optimization and fine tuning of the magnetic and thermoresponsive properties of individual components (nanoparticles and microgels) before assembling them so that the hybrid core-shell structure retains all the individual properties. The,decisive parameter when exploiting the thermoresponsive and magnetic properties in such hybrid core-shell structures is the amount of heat transfer from the magnetic core onto the thermosensitive (loaded) microgel (for the subsequent heat-triggered release of drugs). Inductive heat study reveals that the heat generated by the magnetic narroparticles is sufficient to cause the collapse of the microgel above its volume phase transition temperature. Successful confinement of positively and negatively charged magnetic nanoparticles between polyelectrolyte layers is achieved using the layer-by-layer deposition onto the microgel. Dynamic light scattering measurements show (i) the presence of each layer successfully deposited, (ii) the preservation of thermoresponsivity in the coated microgel, and (iii) that the magnetic nanoparticles do not get detached during the phase transition of the microgel. Electrophoresis measurements confirm charge reversal at every stage of layering of polycations, polyanions and magnetic nanoparticles. This unique combination of thermoresponsivity and magnetism opens up novel perspectives towards remotely controlled drug carriers. (c) 200

Two quantum analogues of Fisher information from a large deviation viewpoint of quantum estimation

We discuss two quantum analogues of Fisher information, symmetric logarithmic derivative (SLD) Fisher information and Kubo-Mori-Bogoljubov (KMB) Fisher information from a large deviation viewpoint of quantum estimation and prove that the former gives the true bound and the latter gives the bound of consistent superefficient estimators. In another comparison, it is shown that the difference between them is characterized by the change of the order of limits.Comment: LaTeX with iopart.cls, iopart12.clo, iopams.st

Inconsistency of the MLE for the joint distribution of interval censored survival times and continuous marks

This paper considers the nonparametric maximum likelihood estimator (MLE) for the joint distribution function of an interval censored survival time and a continuous mark variable. We provide a new explicit formula for the MLE in this problem. We use this formula and the mark specific cumulative hazard function of Huang and Louis (1998) to obtain the almost sure limit of the MLE. This result leads to necessary and sufficient conditions for consistency of the MLE which imply that the MLE is inconsistent in general. We show that the inconsistency can be repaired by discretizing the marks. Our theoretical results are supported by simulations.Comment: 27 pages, 4 figure

Quantum Chi-Squared and Goodness of Fit Testing

The density matrix in quantum mechanics parameterizes the statistical properties of the system under observation, just like a classical probability distribution does for classical systems. The expectation value of observables cannot be measured directly, it can only be approximated by applying classical statistical methods to the frequencies by which certain measurement outcomes (clicks) are obtained. In this paper, we make a detailed study of the statistical fluctuations obtained during an experiment in which a hypothesis is tested, i.e. the hypothesis that a certain setup produces a given quantum state. Although the classical and quantum problem are very much related to each other, the quantum problem is much richer due to the additional optimization over the measurement basis. Just as in the case of classical hypothesis testing, the confidence in quantum hypothesis testing scales exponentially in the number of copies. In this paper, we will argue 1) that the physically relevant data of quantum experiments is only contained in the frequencies of the measurement outcomes, and that the statistical fluctuations of the experiment are essential, so that the correct formulation of the conclusions of a quantum experiment should be given in terms of hypothesis tests, 2) that the (classical) $\chi^2$ test for distinguishing two quantum states gives rise to the quantum $\chi^2$ divergence when optimized over the measurement basis, 3) present a max-min characterization for the optimal measurement basis for quantum goodness of fit testing, find the quantum measurement which leads both to the maximal Pitman and Bahadur efficiency, and determine the associated divergence rates.Comment: 22 Pages, with a new section on parameter estimatio