Central Path Research Articles

The seroprevalence of West Nile Virus in Israel: A nationwide cross sectional study

West Nile Virus (WNV) is endemic in Israel, affecting yearly 40–160 individuals. Israel is located on a central migratory path between Africa and Eurasia and most West Nile Fever (WNF) cases reported in recent years were among residents of the coastal plain. The aim of the study was to evaluate the seroprevalence of WNV among the Israeli population and to assess correlates for WNV infection. A cross-sectional nationwide serologic survey was conducted using 3,145 serum samples collected by the national Israeli serum bank during 2011–2014, representing all age and population groups in Israel. Prevalence rates of WNV IgG antibodies were determined. Logistic regressions models were applied to assess the associations between demographic characteristics and WNV seropositivity. 350 samples were positive to WNV (11.1%; 95%CI: 10.0–12.3%). In the multivariable analysis, there was a significant association between seropositivity and the Arab population group vs. Jews and others (OR = 1.86, 95%CI: 1.37–2.52), the time lived in Israel [50–59 years vs. 0–9 years; OR = 10.80 (95%CI: 1.03–113.46) and ≥60 years vs. 0–9 years; OR = 14.00 (1.32–148.31)] residence area] Coastal Plain, Inland Plain (Shfela) and Great Rift Valley vs. Upper Galilee; OR = 2.24 (95%CI: 1.37–3.65), OR = 2.18 (95%CI: 1.18–4.03), OR = 1.90 (95%CI: 1.10–3.30), respectively [and rural vs. urban settlement (OR = 1.65, 95%CI: 1.26–2.16). People, who reside in the Coastal Plain, Inland Plain and Great Rift Valley, should be aware of the risk of contracting WNV and reduce exposure to mosquito bites, using insect repellents, and wearing protective clothing. The Ministry of Environmental Protection should be active in reducing the mosquito population by eliminating sources of standing water, a breeding ground for mosquitoes.

Automated analysis of human cochlea shape variability from segmented μCT images

The aim of this study is to define an automated and reproducible framework for cochlear anatomical analysis from high-resolution segmented images and to provide a comprehensive and objective shape variability study suitable for cochlear implant design and surgery planning. For the scala tympani (ST), the scala vestibuli (SV) and the whole cochlea, the variability of the arc lengths and the radial and longitudinal components of the lateral, central and modiolar paths are studied. The robustness of the automated cochlear coordinate system estimation is validated with synthetic and real data. Cochlear cross-sections are statistically analyzed using area, height and width measurements. The cross-section tilt angle is objectively measured and this data documents a significant feature for occurrence of surgical trauma.

Cellular and Molecular Mechanisms of Diuretic Plants: An Overview.

Heart failure, hypertension, cirrhosis and nephritic syndrome are among conditions that alter volume and composition of body fluids and are modulated by diuretics. Natural products are important source of diuretics and have been considered remarkable alternative with greater effectiveness and fewer side effects. However, many of these plants used in traditional medicine must be scientifically assessed about their efficacy and toxicity. Despite the large number of published articles claiming that plants or plant-derived components may act as diuretic agents, few studies have addressed the mechanism of action of medicinal plants. Thus, the aim of this review was to provide an overview of the current knowledge about the major cellular and molecular mechanisms of diuretic plants and/or their main compounds. Many well-established mechanisms (water channels, renal carriers, nitric oxide-cGMP and prostaglandin-cAMP pathways, renin-angiotensin and kinin-kallikrein systems, carbonic anhydrase, and osmotic effects), along with other newly identified targets, are connected to the diuretic activity of many natural products. However, the central path responsible for the activity of these agents remains unclear. Further studies may help clarifying the central role of each of these pathways in the pleiotropic response of these agents.

Implementation of a tobacco-free workplace program at a local mental health authority.

Tobacco-free workplace policies that incorporate evidence-based practices can increase the reach and effectiveness of tobacco dependence treatment among underserved populations but may be underutilized due to limited knowledge about implementation processes. This paper describes the implementation of a comprehensive tobacco-free workplace program at a behavioral healthcare community center in Texas. The center participated in a tobacco-free workplace program implementation project that provided guidance and resources and allowed center autonomy in implementation. Six employee-based subcommittees guided implementation of program components including consumer and staff surveys, policy development, signage, tobacco use assessments, communication, and nicotine replacement distribution. Timeline development, successes, challenges, lessons learned, and sustainability initiatives are delineated. Concerns about the tobacco-free workplace policy from the center's staff and consumers were gradually replaced by strong support for the initiative. Program success was enabled by consistent support from the center's leadership, publicity of program efforts, and educational campaigns. The center surpassed the program expectations when it adopted a tobacco-free hiring policy, which was not an initial program goal. This center's path to a tobacco-free workplace provides an implementation and sustainability model for other behavioral health community centers and other organizations to become tobacco free.

Two wide neighborhood interior-point methods for symmetric cone optimization

In this paper, we present two primal---dual interior-point algorithms for symmetric cone optimization problems. The algorithms produce a sequence of iterates in the wide neighborhood $$\mathcal {N}(\tau ,\,\beta )$$N(ź,β) of the central path. The convergence is shown for a commutative class of search directions, which includes the Nesterov---Todd direction and the xs and sx directions. We derive that these two path-following algorithms have $$\begin{aligned} \text{ O }\left( \sqrt{r\text{ cond }(G)}\log \varepsilon ^{-1}\right) , \text{ O }\left( \sqrt{r}\left( \text{ cond }(G)\right) ^{1/4}\log \varepsilon ^{-1}\right) \end{aligned}$$Orcond(G)logź-1,Orcond(G)1/4logź-1iteration complexity bounds, respectively. The obtained complexity bounds are the best result in regard to the iteration complexity bound in the context of the path-following methods for symmetric cone optimization. Numerical results show that the algorithms are efficient for this kind of problems.

An arc-search infeasible interior-point algorithm for horizontal linear complementarity problem in the neighbourhood of the central path

ABSTRACTAn arc-search infeasible interior point algorithm is proposed for solving a horizontal linear complementarity problem. The algorithm produces a sequence of iterates in the negative infinity neighbourhood of the central path and searches the solutions along the ellipses that approximate the whole central path. We study the theoretical convergence properties and also establish polynomial complexity bound for the proposed algorithm. Moreover, our numerical results suggest that the proposed algorithm is very efficient and competitive.

Primal-dual entropy-based interior-point algorithms for linear optimization

We propose a family of search directions based on primal-dual entropy in the context of interior-point methods for linear optimization. We show that by using entropy-based search directions in the predictor step of a predictor-corrector algorithm together with a homogeneous self-dual embedding, we can achieve the current best iteration complexity bound for linear optimization. Then, we focus on some wide neighborhood algorithms and show that in our family of entropy-based search directions, we can find the best search direction and step size combination by performing a plane search at each iteration. For this purpose, we propose a heuristic plane search algorithm as well as an exact one. Finally, we perform computational experiments to study the performance of entropy-based search directions in wide neighborhoods of the central path, with and without utilizing the plane search algorithms.

Some New Graceful Lobsters with Pendant Vertices with Central Paths

The objective of this article is to give graceful labeling to some new classes of lobsters in a bid to resolve the three and half decade old Bermond’s conjecture that all lobsters are graceful. Here we use the method of component moving transformation such as the transfer of the first and second type and the derived transformations such as BD8TF, 1JTF, and 2JTF for generating graceful trees from a given one. In a bid to resolve Bermond’s conjecture here we give graceful labelings to many classes of lobsters possessing at least one of the two distinct features from those found in the literature as detailed below. 1.The central paths of the lobsters contain one or more vertices which do not have any neighbour apart from those on the central path. 2.One or more vertices of the central paths are attached to leaves. 3. The vertices on the central path may be attached to any of the fifteen different combination of odd, even, and pendant branches.

Analysis of some interior point continuous trajectories for convex programming

In this paper, we analyse three interior point continuous trajectories for convex programming with general linear constraints. The three continuous trajectories are derived from the primal–dual path-following method, the primal–dual affine scaling method and the central path, respectively. Theoretical properties of the three interior point continuous trajectories are fully studied. The optimality and convergence of all three interior point continuous trajectories are obtained for any interior feasible point under some mild conditions. In particular, with proper choice of some parameters, the convergence for all three interior point continuous trajectories does not require the strict complementarity or the analyticity of the objective function. These results are new in the literature.

Construction of proximal distances over symmetric cones

This paper is devoted to the study of proximal distances defined over symmetric cones, which include the non-negative orthant, the second-order cone and the cone of positive semi-definite symmetric matrices. Specifically, our first aim is to provide two ways to build them. For this, we consider two classes of real-valued functions satisfying some assumptions. Then, we show that its corresponding spectrally defined function defines a proximal distance. In addition, we present several examples and some properties of this distance. Taking into account these properties, we analyse the convergence of proximal-type algorithms for solving convex symmetric cone programming (SCP) problems, and we study the asymptotic behaviour of primal central paths associated with a proximal distance. Finally, for linear SCP problems, we provide a relationship between the proximal sequence and the primal central path.

漏洩検知部を有する四葉伝熱管内凝縮熱伝達特性

This study deals with condensing heat transfer of HFC-134a in a quadrilobed tube with a clearance for leak detection. In the experiments on condensation heat transfer, a deterioration on heat transfer perfomance that might be caused by maldistribution of refrigerant into five pathes in the quadrilobed shape was observed. Especially, it was estimated that mass flow rate in the center path might become larger due to lower condensing rate in the center path . Therefore, in order to improve the heat transfer performance, the center path was blocked by inserting a copper rod. The effect by the insert on condensing heat transfer and pressure loss characteristics was evaluated in the experiments for a horizontal short double-tube heat exchanger with the heating length of 200 mm. As the result, improvement effects, such as reduction in pressure loss and enhancement of condensing heat transfer for the same mass flux, could be obtained.

Modified polynomial-time full-NT-step infeasible interior-point algorithm for symmetric optimisation

In this paper, we improve the full Nesterov-Todd (NT)-step infeasible-interior-point algorithm for symmetric optimisation of Gu et al. (2011). Our proposed algorithm differs from Gu et al.'s algorithm such that it has the advantage that no centring steps are needed. In each main iteration of Gu et al.'s algorithm, one feasibility and a few centring steps are needed to get feasible iterates for a pair of perturbed problems, close enough to its central path. In this paper, we perform only one full-NT-step in each main iteration of the algorithm. Despite eliminating the centring steps, the complexity bound of our algorithm matches the best obtained one for symmetric optimisation.

Constant Scallop-Height Tool Path Generation for Ball-End Mill Cutters and Three-Axis CNC Milling Machines

Generating the best surface quality with minimum machining time is the main objective of CNC milling. Modern CAM systems do not always ensure constant scallop height even though an appropriate option has been specified for CNC program generation. The presented paper proposes simple mathematical relations providing a tool path with constant scallop height. The relations have been verified with a simulation of a spherical workpiece surface machining using the CAM program. By using such tool path processing, the productivity improved by for 10 percent. Thus, the paper presents a mathematical model, which links the relationship between scallops height, the mill sphere center path, and the workpiece surface. The model is based on the condition of featuring the contact of three circles in the section orthogonal to feed motion vector. The model is rather simple, rather reliable and provides a means of constant scallops height ensuring.

A new second-order corrector interior-point algorithm for P*(k)-LCP

In this paper, we propose a second-order corrector interior-point algorithm for solving P*(k)- linear complementarity problems. The method generates a sequence of iterates in a wide neighborhood of the central path introduced by Ai and Zhang. In each iteration, the method computes a corrector direction in addition to the Ai-Zhang direction, in an attempt to improve performance. The algorithm does not depend on the handicap k of the problem, so that it can be used for any P*(k)-linear complementarity problems. It is shown that the iteration complexity bound of the algorithm is O ((1+k)3 ? nL). Some numerical results are provided to illustrate the performance of the algorithm.

A full-Newton step feasible interior-point algorithm for P∗(κ)-LCP based on a new search direction

In this paper, we present a full-Newton step feasible interior-point algorithm for a P ∗ ( κ ) linear complementarity problem based on a new search direction. We apply a vector-valued function generated by a univariate function on nonlinear equations of the system which defines the central path. Furthermore, we derive the iteration bound for the algorithm, which coincides with the best-known iteration bound for these types of algorithms. Numerical results show that the proposed algorithm is competitive and reliable.

Attitude control of an underactuated spacecraft using quaternion feedback regulator and tube-based MPC

Feasibility of achieving 3-axis stabilization of an asymmetric spacecraft for cases where there is no control available in one axis (underactuated spacecraft) is explored in this paper. A novel control design methodology is presented which can stabilize the underactuated spacecraft and steer it to the origin. A passive fault tolerant control (FTC) is defined which controls and maintains the attitude of the spacecraft near the desired point in presence of uncertainties, disturbances, control constraints and actuator faults. Considering the general conditions of the underactuated spacecraft, a hybrid controller combining a quaternion feedback regulator (QFR) with a tube-based model predictive controller (MPC) is developed based on the nonlinear kinematic and dynamic equations of the spacecraft motion. The hybrid controller is composed of two control stages. At the first stage, QFR decreases the angular velocities and brings the state vector to an acceptable region for the next stage. Then, tube-based MPC solves two optimal control problems, a standard problem for the nominal system to define a central guide path, and an ancillary problem to steer the state vector towards the central path with semi-optimal control effort. Numerical simulation results obtained for the underactuated spacecraft merely indicate effectiveness of the proposed attitude control method.

What governs successful performance of a complex whole body movement: The Kovacs release-regrasp on horizontal bar?

The Kovacs is a release and regrasp skill performed on the horizontal bar in men׳s artistic gymnastics. It is a popular skill in elite competitive gymnastics with over 40% of male gymnasts performing a variation of the Kovacs at the London 2012 Olympics. In the qualifying competition 84% of Kovacs were successfully regrasped, with the remaining 16% resulting in a fall. The aim of the present study was to determine why some gymnasts are more successful than others at regrasping the bar, with a secondary aim to determine how a less successful gymnast could alter his technique in order to become more successful. Nine performances of the Kovacs by each of two gymnasts, one 100% successful and one 11% successful, were analysed to determine differences in release and regrasp parameters. The technique of the less successful gymnast was optimised using a computer simulation model to increase the percentage of catches (success rate). The successful gymnast had larger and more consistent release windows and a radial velocity towards the bar at regrasp. The less successful gymnast had higher horizontal velocity at release and a mean radial velocity away from the bar at regrasp. Optimising his simulated technique increased the rate of success from 11% to 93%. The actions prior to release were performed earlier than in the recorded performances leading to a more vertical path of the mass centre at release and a radial velocity towards the bar at regrasp.

Orbital Angular Momentum Generation With Ultra-Compact Bragg-Assisted Silicon Microrings

A silicon microring resonator with an embedded Bragg grating for orbital angular momentum (OAM) generation is designed and experimentally demonstrated. The device consists of a 3.9 ${\mu }\text{m}$ -radius ring resonator with cylindrical silica holes along the central path and exploits the radially polarized component of the propagating electric field in the resonator’s strip waveguide, enabling both the bandwidth broadening and the emission efficiency improvement, while reducing the footprint. The experimental results show that the device achieves a 3dB bandwidth of 134 GHz and an efficiency up to 6.5%. The interference patterns are measured for different OAM orders in which the number of spirals are clearly visible proving that the device can support different topological charges. Results are in good agreement with simulations.

Offensive strategies in the European Football Championship 2012.

The aim of this study was to identify the independent and interactive effects of possession strategy, pitch location, and game period on the offensive actions performed by the winning teams in the 2012 European Football Championship. The non-clinical magnitude-based inferences method was used to interpret the true effect of the performance indicators on the response variable. The offensive team possessions were grouped into winning (n = 2035) and losing (n = 2071). The winning teams performed offensive processes mainly using the possession play strategy (OR: 0.75, very likely negative effect of the direct play). When the analysis included the pitch location, negative interaction effect was found for the direct play, which ended up in the central path (OR: 0.70, very likely negative effect). On the contrary, the direct play in the second half of the match seemed to produce an effect on the probability of the winning teams performing offensive processes (OR: 1.59, most likely positive effect). The results of multivariate analyses showed that the offensive team possession profiles required a careful investigation because the possession strategy changed under the conjoint effect of pitch location and game period.

An Arc-search Interior Point Method in the 𝒩−∞ Neighborhood for Symmetric Optimization

In this paper, we propose an arc-search infeasible interior point algorithm for symmetric optimization using the negative infinity neighborhood of the central path. The algorithm searches the optimizers along the ellipses that approximate the entire central path. The convergence of the algorithm is shown for the set of commutative scaling class, which includes some of the most interesting choice of scalings such as xs, sx and the Nesterov-Todd scalings.