Exchange rate and oil price interactions in transition economies: Czech republic, Hungary and Poland

This study investigates causal dynamics between crude oil prices and exchange rates in Czech Republic, Poland and Hungary by employing monthly data from the beginning of flexible exchange regime in each country to December 2011. The study benefits from the recent advance in the time series econometric analysis and carries out linear causality, non-linear causality, volatility spillover and frequency domain causality tests. The frequency domain causality analysis results imply that oil price fluctuations affect real exchange rates in the long run in Poland and Czech Republic. On the other hand, frequency domain causality test results indicate that oil price fluctuations do not affect exchange rate in any period in Hungary despite its economy’s high imported energy dependency. © 2015, Savez Ekonomista Vojvodine. All rights reserved

Evaluation of the effects of photobiomodulation on vertebras in two rat models of experimental osteoporosis

The aim of this study was to evaluate the effects of photobiomodulation (PBM) on cancellous bone in rat models of ovariectomized induced osteoporosis (OVX-D) and glucocorticoid-induced osteoporosis (GIOP). The experiment comprised of nine groups. A group of healthy rats was used for baseline evaluations. The OVX-D rats were further divided into groups as follows: control rats with osteoporosis, OVX-D rats that received alendronate (1 mg/kg 60 days), OVX-D rats treated with pulsed wave laser (890 nm, 80 Hz, 900 s, 0.0061 W/cm(2), 5.5 J/cm(2), three times a week, 60 days), and OVX-D rats treated with alendronate + pulsed laser. Dexamethasone was administered to the remaining rats that were split into four groups: control, alendronate-treated rats, laser-treated rats, and GIOP rats treated with alendronate + laser. T12, L1, L2, and L3 vertebrae were subjected to laser. Results of the current study demonstrated that OVX-D and GIOP significantly decreased some stereological parameters, and type 1 collagen gene expression compared to the healthy group. There was a significant increase in osteoclast number in both OVX-D and glucocorticoid administration compared to the healthy group. However, the detrimental effect of the OVX-D procedure on bone was more serious than glucocorticoid administration. Results showed that laser alone had a detrimental effect on trabecular bone volume, and cortical bone volume in groups GIOP and OVX-D compared to those in the healthy group. Alendronate significantly improved total vertebral bone volume, trabecular bone volume, and cortical bone volume, in GIOP and OVX-D groups compared to the laser-treated groups. Furthermore, the alendronate + laser in OVX-D rats and GIOP rats produced significantly increased osteoblast number and type 1 collagen gene expression and caused a significant decrease in osteoclast number compared to the controls

Evaluating the Decoding the Disciplines paradigm that is used for developing disciplinary habits of mind: A systematic literature review

This article reports on a systematic review of the literature to evaluate the Decoding the Disciplines paradigm (henceforth “DtD”) in the development of expert disciplinary habits of mind in student learning. A search was conducted utilising various databases (EBSCOhost, DOAJ, JSTOR, SAGE Journals Online, Scopus, Wiley Online and uKwazi) (Library Search Engine) for the period 2004 to 2020. More than 500 papers, retrieved from nine scholarly databases, were screened, based on title and abstract, resulting in 33 shortlisted papers for analysis. The researcher and one independent reviewer assessed the methodological quality of the shortlisted articles. Five countries are represented in this study. The results of this review highlighted the impact that the DtD has on the development of expert ways of thinking in learners. The case studies attest to the fact that several insights, namely 1) Concretising abstract phenomena; 2) Overcoming emotional bottlenecks; 3) Making expert habits of mind explicit to the learner; 4) Trans-disciplinary approaches and the T-Shaped learner and 5) Synergies between threshold concepts and information literacy habits of mind, are capabilities that the DtD process could cultivate in student learning to overcome complex bottlenecks

Robust Entanglement in Anti-ferromagnetic Heisenberg Chains by Single-spin Optimal Control

We demonstrate how near-perfect entanglement (in fact arbitrarily close to maximal entanglement) can be generated between the end spins of an anti-ferromagnetic isotropic Heisenberg chain of length $N$, starting from the ground state in the $N/2$ excitation subspace, by applying a magnetic field along a given direction, acting on a single spin only. Temporally optimal magnetic fields to generate a singlet pair between the two end spins of the chain are calculated for chains up to length 20 using optimal control theory. The optimal fields are shown to remain effective in various non-ideal situations including thermal fluctuations, magnetic field leakage, random system couplings and decoherence. Furthermore, the quality of the entanglement generated can be substantially improved by taking these imperfections into account in the optimization. In particular, the optimal pulse of a given thermal initial state is also optimal for any other initial thermal state with lower temperature.Comment: 10 pages, revte

Engineering Long Range Distance Independent Entanglement through Kondo Impurities in Spin Chains

We investigate the entanglement properties of the Kondo spin chain when it is prepared in its ground state as well as its dynamics following a single bond quench. We show that a true measure of entanglement such as negativity enables to characterize the unique features of the gapless Kondo regime. We determine the spatial extent of the Kondo screening cloud and propose an ansatz for the ground state in the Kondo regime accessible to this spin chain; we also demonstrate that the impurity spin is indeed maximally entangled with the Kondo cloud. We exploit these features of the entanglement in the gapless Kondo regime to show that a single local quench at one end of a Kondo spin chain may always induce a fast and long lived oscillatory dynamics, which establishes a high quality entanglement between the individual spins at the opposite ends of the chain. This entanglement is a footprint of the presence of the Kondo cloud and may be engineered so as to attain - even for very large chains- a constant high value independent of the length; in addition, it is thermally robust. To better evidence the remarkable peculiarities of the Kondo regime, we carry a parallel analysis of the entanglement properties of the Kondo spin chain model in the gapped dimerised regime where these remarkable features are absent

Initializing an unmodulated spin chain to operate as a high quality quantum data-bus

We study the quality of state and entanglement transmission through quantum channels described by spin chains varying both the system parameters and the initial state of the channel. We consider a vast class of one-dimensional many-body models which contains some of the most relevant experimental realizations of quantum data-buses. In particular, we consider spin-1/2 XY and XXZ model with open boundary conditions. Our results show a significant difference between free-fermionic (non-interacting) systems (XY) and interacting ones (XXZ), where in the former case initialization can be exploited for improving the entanglement distribution, while in the latter case it also determines the quality of state transmission. In fact, we find that in non interacting systems the exchange with fermions in the initial state of the chain always has a destructive effect, and we prove that it can be completely removed in the isotropic XX model by initializing the chain in a ferromagnetic state. On the other hand, in interacting systems constructive effects can arise by scattering between hopping fermions and a proper initialization procedure. Remarkably our results are the first example in which state and entanglement transmission show maxima at different points as the interactions and initializations of spin chain channels are varied.Comment: 10 pages, 7 figure

Current Implant Surface Technology: An Examination of Their Nanostructure and Their Influence on Fibroblast Alignment and Biocompatibility

Systematic reviews indicate that breast implant texture confers a protective effect on capsular contracture. Fibroblasts are affected by micro- and nanotopographies. Few previous studies have investigated the inherent topographies of existing breast implants and the surfaces with which body tissue is exposed. Aims: To examine currently available breast implant surfaces at high resolution and evaluate features within their surface that have been demonstrated to influence fibroblast alignment. Methods: Using scanning electron and light microscopy, 5 distinct smooth and textured silicone implants including the Mentor Siltex® (Mentor Corporation, Santa Barbara, Calif) and Allergan Biocell® (Allergan Medical Corporation, Santa Barbara, Calif) surfaces were investigated at high magnification to illustrate their intrinsic surface topographies. Results: The images obtained illustrate remarkable micro- and nanoscale topographies. Each surface produced a distinctive microenvironment capable of influencing cell shape and thus biointegration. These features are illustrated by our unique, high-magnification images. The smooth surface exhibits a shallow, regular, 5-µm period rippled texture that may explain higher reported contracture rates, while the Biocell and Siltex surfaces show 100- to 200-µm deep but random features that have been shown to anchor the implant to breast tissue and reduce contracture. Results allow a cell's eye view of these implants, with an explanation of why these types of topographies influence the success of these implants. Conclusions: We assessed commonly available silicone implants and offer a unique overview into their surface topographies and how they are manufactured. We conclude that these surfaces require modernization. Our findings provide further insight into potential interactions between cellular assemblies and artificial surfaces and may contribute to the development of improved implant surfaces

Voltage-controlled Hubbard spin transistor

Transistors are key elements for enabling computational hardware in both classical and quantum domains. Here we propose a voltage-gated spin transistor using itinerant electrons in the Hubbard model which acts at the level of single electron spins. Going beyond classical spintronics, it enables the controlling of the flow of quantum information between distant spin qubits. The transistor has two modes of operation, open and closed, which are realized by two different charge configurations in the gate of the transistor. In the closed mode, the spin information between source and drain is blocked while in the open mode we have free spin information exchange. The switching between the modes takes place within a fraction of the operation time which allows for several subsequent operations within the coherence time of the transistor. The system shows good resilience against several imperfections and opens up a practical application for quantum dot arrays

Quantum phase transition detected through one-dimensional ballistic conductance

A quantum phase transition is an unequivocal signature of strongly correlated many-body physics. Signatures of such phenomena are yet to be observed in ballistic transport through quantum wires. Recent developments in quantum wires have made it possible to enhance the interaction between the electrons. Here we show that hitherto unexplained anticrossing between conduction energy subbands, observed in such experiments, can be explained through a simple yet effective discretized model which undergoes a second-order quantum phase transition within the Ising universality class. Accordingly, we observe how the charge distribution, transverse to the direction of the wire, will vary across the phase transition. We show that data coming from three different samples with differing electron densities and gate voltages show a remarkable universal scaling behavior, determined by the relevant critical exponent, which is only possible near a quantum phase transition

Quantum phase transition detected through one-dimensional ballistic conductance

A quantum phase transition is an unequivocal signature of strongly correlated many-body physics. Signatures of such phenomena are yet to be observed in ballistic transport through quantum wires. Recent developments in quantum wires have made it possible to enhance the interaction between the electrons. Here we show that hitherto unexplained anticrossing between conduction energy subbands, observed in such experiments, can be explained through a simple yet effective discretized model which undergoes a second-order quantum phase transition within the Ising universality class. Accordingly, we observe how the charge distribution, transverse to the direction of the wire, will vary across the phase transition. We show that data coming from three different samples with differing electron densities and gate voltages show a remarkable universal scaling behavior, determined by the relevant critical exponent, which is only possible near a quantum phase transition