Quantum Nanomagnetism

In this paper we discuss some of our most important results in quantum nanomagnets in the last twenty years. We start with the tunnelling of the magnetic moment in single domain particles, then we will move to molecular magnets to explain both resonant spin tunnelling and quantum magnetic deflagration and we will finish discussing the quantum phenomena recently observed in vortices of two dimensional disks and in type I superconductors. Probably the most important question to answer in the cases presented in this paper refers to the possibility to detect both coherent phonons and photons from the demagnetization process of molecular magnets as well as the fact to go deeper in the quantum phenomena observed in vortices of two dimensional disks and in type I superconductors. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3535

Calcium Ions Effect on Planaria Feeding Behavior

Calcium is important for the contraction of muscles, neurotransmission, and signaling in animals. Like other active movers, invertebrate planarian flatworms have musculature for motility. Therefore, it can be inferred that without the proper concentration of calcium ions in the water they can’t undulate or extend the pharynx, a muscular feeding structure. Planaria are generally cultured at a 0.5 g/L concentration of instant ocean sea salt (IOS), which contains calcium ion of 0.126 mM. However, there is uncertainty in the concentrations of important ions, such as calcium, which are optimal for the maintenance and homeostasis of the planaria. Previous research on water quality and planarian behavior has focused on species Schmidtea mediterranea, Dugesia japonica, and Girardia guanjuatiensis, but not Girardia dorotocephala (G. dorotocephala), the species currently cultured at Lynn University. Because other than being just readily available these species of worms haven’t undergone research in the frame of calcium ions. G. dorotocephala may require different concentrations of calcium ions than those of other relative species, an analysis of their requirements is warranted. For this experiment, we plan to specify which concentration of calcium is required for G. dorotocephala cultures. We hypothesize that G. dorotocephala requires micronutrient concentrations differing from standard IOS water, as has been observed for other species of planaria. We base this hypothesis on our observations of their feeding behavior following starvation. To conduct this experiment, we plan to assay food localization behavior under different concentrations of calcium

Learning and policy search in stochastic dynamical systems with Bayesian neural networks

We present an algorithm for policy search in stochastic dynamical systems using model-based reinforcement learning. The system dynamics are described with Bayesian neural networks (BNNs) that include stochastic input variables. These input variables allow us to capture complex statistical patterns in the transition dynamics (e.g. multi-modality and heteroskedasticity), which are usually missed by alternative modeling approaches. After learning the dynamics, our BNNs are then fed into an algorithm that performs random roll-outs and uses stochastic optimization for policy learning. We train our BNNs by minimizing a-divergences with a = 0.5, which usually produces better results than other techniques such as variational Bayes. We illustrate the performance of our method by solving a challenging problem where model-based approaches usually fail and by obtaining promising results in real-world scenarios including the control of a gas turbine and an industrial benchmark

Coherent control of injection currents in high-quality films of Bi2Se3

Films of the topological insulator Bi2Se3 are grown by molecular beam epitaxy with in-situ reflection high-energy electron diffraction. The films are shown to be high-quality by X-ray reflectivity and diffraction and atomic-force microscopy. Quantum interference control of photocurrents is observed by excitation with harmonically related pulses and detected by terahertz radiation. The injection current obeys the expected excitation irradiance dependence, showing linear dependence on the fundamental pulse irradiance and square-root irradiance dependence of the frequency-doubled optical pulses. The injection current also follows a sinusoidal relative-phase dependence between the two excitation pulses. These results confirm the third-order nonlinear optical origins of the coherently controlled injection current. Experiments are compared to a tight-binding band structure to illustrate the possible optical transitions that occur in creating the injection current.Comment: 11 pages, 3 figure, journal articl

Surgical Versus Medical Treatment for Diabetic Macular Edema: A Review

We aimed to compare the results of pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling, an alternative therapeutic strategy, with those of medical treatment for chronic macular edema. We conducted a review of the literature on the microscopic, anatomical, and functional reasons for performing PPV with ILM peeling in patients with diabetic macular edema (DME). We searched the PubMed database for articles published between 2000 and 2017. We used the medical subject heading “vitrectomy diabetic macular edema†and the keywords “diabetic macular edemaâ€, “internal limiting membrane peelingâ€, “pars plana vitrectomyâ€, “diabetic retinopathyâ€, and “optical coherence tomographyâ€. Analysis of the literature revealed that cytokines, vascular endothelial growth factor, reactive oxygen species (ROS), and advanced glycation end-products (AGEs) play a unique role in DME. The vitreous cavity serves as a physiological reservoir for all inflammatory molecules. AGE receptors are localized at the footplates of Müller cells and the external limiting membrane (ELM). The footplates of Müller cells are in contact with the ILM, which suggests that they might be responsible for the structural damage (i.e., thickening) observed in the ILM of patients with DME. Therefore, PPV could allow a reduction of cytokines and pro-inflammatory molecules from the vitreous cavity. ILM peeling could eliminate not only the physical traction of a thickened structure, but also the natural reservoir of AGEs, ROS, and inflammatory molecules. PPV with ILM peeling is a surgical option that should be considered when treating patients with chronic DME

Effect of Uterine Manipulation on Postcalving Fertility of Brahman Cows and First-Calf Heifers

Last updated: 6/1/200