Unified model of voltage/current mode control to predict saddle-node bifurcation

A unified model of voltage mode control (VMC) and current mode control (CMC) is proposed to predict the saddle-node bifurcation (SNB). Exact SNB boundary conditions are derived, and can be further simplified in various forms for design purpose. Many approaches, including steady-state, sampled-data, average, harmonic balance, and loop gain analyses are applied to predict SNB. Each approach has its own merits and complement the other approaches.Comment: Submitted to International Journal of Circuit Theory and Applications on December 23, 2010; Manuscript ID: CTA-10-025

Relative entropy of entanglement for certain multipartite mixed states

We prove conjectures on the relative entropy of entanglement (REE) for two families of multipartite qubit states. Thus, analytic expressions of REE for these families of states can be given. The first family of states are composed of mixture of some permutation-invariant multi-qubit states. The results generalized to multi-qudit states are also shown to hold. The second family of states contain D\"ur's bound entangled states. Along the way, we have discussed the relation of REE to two other measures: robustness of entanglement and geometric measure of entanglement, slightly extending previous results.Comment: Single column, 22 pages, 9 figures, comments welcom

Effects of Parkinson’s disease on optic flow perception for heading direction during navigation

Visuoperceptual disorders have been identified in individuals with Parkinson’s disease (PD) and may affect the perception of optic flow for heading direction during navigation. Studies in healthy subjects have confirmed that heading direction can be determined by equalizing the optic flow speed (OS) between visual fields. The present study investigated the effects of PD on the use of optic flow for heading direction, walking parameters, and interlimb coordination during navigation, examining the contributions of OS and spatial frequency (dot density). Twelve individuals with PD without dementia, 18 age-matched normal control adults (NC), and 23 young control adults (YC) walked through a virtual hallway at about 0.8 m/s. The hallway was created by random dots on side walls. Three levels of OS (0.8, 1.2, and 1.8 m/s) and dot density (1, 2, and 3 dots/m2) were presented on one wall while on the other wall, OS and dot density were fixed at 0.8 m/s and 3 dots/m2, respectively. Three-dimensional kinematic data were collected, and lateral drift, walking speed, stride frequency and length, and frequency, and phase relations between arms and legs were calculated. A significant linear effect was observed on lateral drift to the wall with lower OS for YC and NC, but not for PD. Compared to YC and NC, PD veered more to the left under OS and dot density conditions. The results suggest that healthy adults perceive optic flow for heading direction. Heading direction in PD may be more affected by the asymmetry of dopamine levels between the hemispheres and by motor lateralization as indexed by handedness.Published versio

COMPARISON OF LINEAR AND ANGULAR SWING VELOCITIES WITH DIFFERENTLY WEIGHTED WARM-UP BATS IN SOFTBALL PLAYERS

Swing velocity has been considered as one of the essential factors of bat swing biomechanics, and traditionally coaches and players think it can be altered by using a differently weighted bat for warm-up before an at bat. The purpose of this study was to examine the effects of 3 differently weighted warm-up bats on 3D linear and angular kinematics. Ten female varsity softball players were recruited and bat swing kinematics with normal (NW), heavy (HW), and light (LW) weighted warm-up bats were collected. Both linear and angular kinematic variables were compared between different bat weights using RMANOVA. Only 1 velocity variable difference between LW and NW, and 4 temporal differences between HW and NW were found. It is suggested that in general, swing kinematics is not altered by differently weighted bats warm-up prior maximal swing

Connections of geometric measure of entanglement of pure symmetric states to quantum state estimation

We study the geometric measure of entanglement (GM) of pure symmetric states related to rank-one positive-operator-valued measures (POVMs) and establish a general connection with quantum state estimation theory, especially the maximum likelihood principle. Based on this connection, we provide a method for computing the GM of these states and demonstrate its additivity property under certain conditions. In particular, we prove the additivity of the GM of pure symmetric multiqubit states whose Majorana points under Majorana representation are distributed within a half sphere, including all pure symmetric three-qubit states. We then introduce a family of symmetric states that are generated from mutually unbiased bases (MUBs), and derive an analytical formula for their GM. These states include Dicke states as special cases, which have already been realized in experiments. We also derive the GM of symmetric states generated from symmetric informationally complete POVMs (SIC~POVMs) and use it to characterize all inequivalent SIC~POVMs in three-dimensional Hilbert space that are covariant with respect to the Heisenberg--Weyl group. Finally, we describe an experimental scheme for creating the symmetric multiqubit states studied in this article and a possible scheme for measuring the permanent of the related Gram matrix.Comment: 11 pages, 1 figure, published versio

High temperature dielectric properties of cubic bismuth zinc tantalate.

Electrical properties of the parent phase in the Bi2O3–ZnO–Ta2O5 ternary system, cubic Bi1.5ZnTa1.5O7 (α-BZT), P, are investigated using impedance spectroscopy. P has permittivity (ɛ′) of 58, dielectric loss (tan δ) of 0.0023 at 30 °C and 1 MHz; temperature coefficient of capacitance (TCC) of −156 ppm/°C in the range of 30–300 °C at 1 MHz. A high degree of dispersion in the permittivity at low frequencies (<1 kHz) and temperatures above 500 °C is apparent. Dielectric losses exhibit non-frequency dependence at low temperatures presenting an increase at temperatures above 500 °C. A decrease of the loss occurs with increasing frequency

Safety and efficacy of stereotactic body radiation therapy in the treatment of pulmonary metastases from high grade sarcoma.

Introduction. Patients with high-grade sarcoma (HGS) frequently develop metastatic disease thus limiting their long-term survival. Lung metastases (LM) have historically been treated with surgical resection (metastasectomy). A potential alternative for controlling LM could be stereotactic body radiation therapy (SBRT). We evaluated the outcomes from our institutional experience utilizing SBRT. Methods. Sixteen consecutive patients with LM from HGS were treated with SBRT between 2009 and 2011. Routine radiographic and clinical follow-up was performed. Local failure was defined as CT progression on 2 consecutive scans or growth after initial shrinkage. Radiation pneumonitis and radiation esophagitis were scored using Common Toxicity Criteria (CTC) version 3.0. Results. All 16 patients received chemotherapy, and a subset (38%) also underwent prior pulmonary metastasectomy. Median patient age was 56 (12-85), and median follow-up time was 20 months (range 3-43). A total of 25 lesions were treated and evaluable for this analysis. Most common histologies were leiomyosarcoma (28%), synovial sarcoma (20%), and osteosarcoma (16%). Median SBRT prescription dose was 54 Gy (36-54) in 3-4 fractions. At 43 months, local control was 94%. No patient experienced G2-4 radiation pneumonitis, and no patient experienced radiation esophagitis. Conclusions. Our retrospective experience suggests that SBRT for LM from HGS provides excellent local control and minimal toxicity