bluuebunny/crossref_metadata_2025 huggingface dataset:
Variable Interval Sampling Based Time Varying Tracking Control With Application to Camless Engine
Authors: Yang Meng , Sun Zongxuan
Published: December 2014

This paper investigates the variable interval sampling based time-varying tracking control in the rotational angle domain. It is found that more sampling points per revolution provide better tracking performance but increase the computational burden. To solve the problem, a varying interval sampling approach is presented to optimize the angular sampling interval for the reference profile, while maintaining the same total number of sampling points. The tracking performance is improved by considering the tracking errors between the sampling points in selecting the optimal sampling intervals. Experimental results from a time-varying internal model based camless engine valve actuation system demonstrate the effectiveness of the proposed method. A quantitative analysis helps to highlight the strength of the variable interval sampling on less computational complexity and better tracking performance.
A Nodal Uncertainty Method to Detect Localized Events From Measured Terrain Surfaces
Authors: Deasy Christopher M. , Ferris John B. , Tjhung Tana , Horn Emily
Published: December 2014

With the advent of terrain surface mapping capabilities comes the necessity to extract useful information from the copious data, particularly localized events. Digital image processing methods for edge detection are applied to road surfaces to locate localized road events. A novel method of edge detection is developed based on the Nodal Uncertainty in which the probability distribution of the nodal heights determines the edges of an event. An example demonstrates that the new method performs at least as well as the best digital image processing methods available. Future development of this work is planned for integration with event characterization and identification methods.
Power Take-Off Control of In-Stream Hydrokinetic Turbines
Authors: Xiros Nikolaos I. , VanZwieten James H. , Sultan Cornel , Tzelepis Vasileios
Published: December 2014

In-stream hydrokinetic electricity production, electricity generation from moving currents without the use of dams, has significant potential for increasing electric power production. This project evaluates a control system designed to regulate rotor rate (rpm) to improve power production from in-stream hydrokinetic turbines. The control algorithm is evaluated using both a numerical model of a rigidly mounted tidal turbine and a numerical model of a moored ocean current turbine system. These two system models are each coupled to an induction electric machine model. Based on the turbine torque-speed characteristic, as well as the asynchronous machine features, a Look-Up-Table (LUT) is used to generate the frequency of the sinusoidal voltages of the three phases to be supplied to the machine. However, to compensate for disturbances and perturbations of the power-plant a PI controller is generating a correction term for electrical frequency superimposed to the output of the LUT. A first round of simulations using the numerical models was performed in order to evaluate the developed algorithms.
Modeling and Characterization of Elastic, Coupling, and Dissipative Nonlinearities in PZT Bimorphs for Vibration Energy Harvesting
Authors: Leadenham S. , Erturk A.
Published: December 2014

In numerous applications of lead zirconate titanate (PZT)-based devices, such as dynamic actuation, vibration control, sensing, and energy harvesting, inherent nonlinearities are inevitably pronounced for a broad range of mechanical and electrical excitation levels. Even in the absence of any geometric nonlinearity, researchers observed and reported nonlinear behavior in PZT-based devices for moderate-to-high excitation levels. Over the past two decades, the softening nonlinearities have been attributed to different phenomena by different research groups, such as purely elastic nonlinear terms and coupling nonlinearity. Dissipative effects of quadratic order have been observed but often attributed to air damping in symmetric structures. In an effort to develop a global nonlinear, non-conservative modeling framework, we combined elastic, coupling, and dissipative nonlinearities to explore primary resonance behavior in bimorph cantilevers for problems of mechanical and electrical excitation. We use this model to characterize the nonlinearities in piezoelectric bimorphs for energy harvesting with a focus on a symmetric brass-reinforced PZT-5A sample under base excitation. Specifically we point out the importance of quadratic nonlinearities in both stiffness and damping. Coupling and higher-order elastic nonlinearities from the electric enthalpy are observed to become effective only for the highest excitation levels close to physical limits of the device with high linear stiffness tested in this work.
A Single-Leader Servo Approach to Multi-Agent Consensus Problems
Authors: Zhao Miaomiao , Wang Miaomiao , Su Housheng , Bhattacharyya Shankar P.
Published: December 2014

In this paper, we discuss the linear consensus problem and group decision regulation in switching undirected multi-agent networks. A single-leader tracking servomechanism approach is introduced to solve this problem. Based on this approach, a stabilizing controller is designed. The proposed controller can achieve state consensus and regulate the group decision value to the desired value. A distinctive feature of this work is to regulate the group decision value without the information of initial states by a concise servomechanism and a virtual leader. As an example of the proposed scheme, the consensus of Unmanned Aerial Vehicles (UAVs) with switching topology is investigated. The numerical example illustrates the effectiveness of the proposed approach for tracking constant signals and piece-wise constant signals, respectively.
Combined Time-Frequency Calculation of pNN50 Metric From Noisy Heart Rate Measurements
Authors: Parsinejad Payam , Rodriguez-Vaqueiro Yolanda , Martinez-Lorenzo Jose Angel , Sipahi Rifat
Published: December 2014

pNN50 is a metric derived from heart rate (HR) measurements, and it is known to correlate with mental-workload changes in human subjects. Conventionally, this metric is calculated based on the variability of successive time periods in peak-to-peak occurrences in HR data. In the case of noisy measurements of HR, however, peak-to-peak detection may not be reliable. Here, we present a combined time-frequency domain analysis, benefiting from Short Time Fourier Transform, by which we can more accurately extract pNN50 metric from noisy HR data. An experimental measurement with added noise is used as a benchmark problem to demonstrate the effectiveness of the approach with noticeable improvement over the conventional time domain peak-to-peak detection algorithm.
Towards the Development of a New Tendon-Driven Minimally Invasive Neurosurgical Intracranial Robot
Authors: Zhao Wenxue , Desai Jaydev P.
Published: December 2014

Surgical resection of deep intracranial tumors under image guidance has significant challenges. The surgeon cannot see beyond the line of sight and it is also difficult to avoid the functional nerves along the path. In this context, the design of a Minimally Invasive Neurosurgical Intracranial Robot (MINIR-II) under continuous MRI is critical. The primary goal of the overall procedure is to avoid critical brain structures to reach the tumor location. Upon reaching the tumor location, the electro-cautery at the robot tip should be controlled to resect the tumor. The new MINIR-II proposed in this work, though not yet MRI compatible, is a dexterous serial chain tendon-driven robot with larger inner space, smaller outer diameter, and less coupling effect of the tendons during actuation. Each joint of the robot was attached with two tendons and they were routed outside the robot around a pulley to achieve rotational degree of freedom. The four-joint assembled robot was manufactured using a rapid prototyping machine and was tested by an experimental setup to demonstrate the motion of the robot.
An Extended Kalman Filter for Collision Detection During Manipulator Contact Tasks
Authors: Zelenak Andy , Pryor Mitch , Schroeder Kyle
Published: December 2014

The development of control strategies that allow stiff industrial robots to operate safely in unstructured environments is a significant challenge. This paper integrates two strategies that improve safety for industrial manipulators in uncertain conditions. First, software compliance in the task space is implemented using force feedback. End-effector compliance is vital for many tasks, such as interacting with humans or manipulating uncertain payloads. Beyond compliance, a collision detection algorithm detects collisions based on joint torque deviation from a dynamic model. Collisions can be detected at any point along the manipulator via loading or impulse anomalies. Joint torque data is typically noisy, and the accuracy of the robot dynamic model is limited, so an Extended Kalman Filter (EKF) was developed to improve the torque estimates. Experiments and demonstrations were performed using a commercially available 7DOF industrial robot. The EKF improved collision detection during unplanned contact tasks, and the method described here is hardware agnostic and extensible.
Human Body Composition Estimation and Model-Free Control Design for Weight Management
Authors: Karimi Mahmood , Rao Ramesh R.
Published: December 2014

It is well known that obesity, a chronic disease, can lead to increased risk of other serious chronic diseases and even death. Knowledge of daily changes in lean muscle mass and body fat can be helpful in developing personalized diet and exercise routines to correct this problem. In this paper, it is assumed that measurements of individual body composition components are available only periodically although the total body weight is tracked on a daily basis. The control input is physical activity whose profile can be constrained to accommodate individual preferences while the energy intake can be arbitrary. We present switching and time delayed feedback based model-free control methods for the dynamic management of body mass and its major components. Additionally, based on human body weight dynamics, estimation of body composition using soft switching-based observer is proposed. Simulation results validate the performance of the proposed controllers and the observer under disturbances in recording energy intake and energy expenditure figures.
Investigation of electrochemical etch differences in AlGaAs heterostructures using Cl2 ion beam assisted etching
Authors: Anglin Kevin , Goodhue William D. , Swint Reuel B. , Porter Jeanne
Published: December 2014

A deeply etched, anisotropic 45° and 90° mirror technology is developed for AlxGa1−xAs heterostructures using a Cl2 ion beam assisted etching system. When etching vertically, using a conductive low-erosion Ni mask, electrochemical etch differences between layers with various Al mole fractions caused nonuniform sidewall profiles not seen in semi-insulating GaAs test samples. These variations, based on alloy composition, were found to be negligible when etching at a 45°. A Si3N4-Ni etch mask is designed in order to electrically isolate charge buildup caused by the incoming Ar+ ion beam to the Ni layer, preventing conduction to the underlying epitaxial layers. This modification produced smoothly etched facets, up to 8 μm in depth, enabling fabrication of substrate–surface-emitting slab-coupled optical waveguide lasers and other optoelectronic devices.
Permittivity of SiO2 for estimating capacitive delays in focused ion beam circuit edit
Authors: Niles David W. , Stout James , Christensen Richard , Rodgers Richard
Published: December 2014

The authors measured the relative permittivity of SiO2 deposited with a focused Ga+ ion beam by creating small parallel plate capacitors on a gold substrate. The relative permittivity of SiO2 ranged from a low of 7.5 to a high of 10.5 depending on the deposition yield, Y, defined as the film volume per ion dose. Lower Y led to the incorporation of metallic Ga0 clusters that increased the relative permittivity. The authors then used the SiO2 to create a parallel plate capacitor that acted as a capacitive delay in a 28 nm technology circuit to improve performance and timing marginality. The circuit segment in question had failed at an overvoltage of 106.1% of the nominal value, providing insufficient margin of operation and reliability. The addition of a 20 fF capacitor increased the upper limit of the performance margin from 106.1% to 108.5% of nominal supply voltage. The realized circuit edit provided conceptual confirmation that an additional delay in the clock signal would improve device performance as predicted by modeling.
High-frequency whistles of Guiana dolphins (Sotalia guianensis) in Guanabara Bay, southeastern Brazil
Authors: Andrade Luciana Guimarães de , Maria Seabra Lima Isabela , Bittencourt Lis , Lemos Bisi Tatiana , Lailson Brito Júnior José , de Freitas Azevedo Alexandre
Published: December 2014

Guiana dolphins produce whistles with a higher frequency and less complexity than most other delphinid species. The present study used a recording system with sampling rate of 192 kHz to describe the high-frequency whistles of Sotalia guianensis in Guanabara Bay, Rio de Janeiro. Eleven acoustic parameters (start, end, minimum, maximum, delta, center and peak frequency, duration, and frequency at 14, 12, and 34 of duration) were measured for all whistles. Whistles with a fundamental frequency up to 66.7 kHz were reported, thereby expanding the known frequency range of this species.
Chapter 9 Students’ Daily Physical Activity Behaviors: The Role of Quality Physical Education in a Comprehensive School Physical Activity Program
Authors: Chen Wiyun , Hypnar Andrew J. , Mason Steve A. , Zalmout Sandy , Hammond-Benett Austin
Published: December 2014

The purpose of this study was to examine the contribution of quality physical education (QPET) in a Comprehensive School Physical Activity Program (CSPAP) which is intended to promote physical activity (PA) behaviors in and outside of schools. Participants were nine elementary physical education teachers and their fourth- and fifth-grade students (n = 1111) in year one, n = 1012 in year 2). The student’s daily PA minutes were assessed using a 7-day PA log. The PE teachers’ levels of QPET were assessed by coding 63 videotaped lessons (Mlessons/teacher = 7.03, SD = .74) using the Assessing Quality Teaching rubrics (AQTR), which consisted of four essential dimensions including Task Design, Task Presentation, Class Management, and Instructional Response. Codes were confirmed through interrater reliability (82.4%, 84.5%, 94%). Data were analyzed through descriptive statistics, bivariate correlations, multiple R-squared regression models, and independent sample t tests. The results indicated that the overall QPET practices (R = .126, R2 = .02, F = 32.387, Sig.= .000, P < .01) and all four essential dimensions (R = .127, R2 = .02, F = 8.560, Sig.= .000, P < .01) were significant contributors to students’ student daily PA behaviors. These predictors were significantly higher in girls (R = .157, R2 = .03, F = 6.15, Sig.= .000, P < .01) than boys (R = .113, R2 = .01, F = 3.57, Sig.= .007, P < .01). The Instructional Response was a significant predictor of PA among girls (β = .12, t = 2,068, Sig. = .039, P < .05 level), but not boys. Further, students’ who experienced high QPET were significantly more physically active than those students who did not have this experience (t = 4.334, df = 2089, Sig. = .000, P < .01). It was concluded that the QPET practices played a critical role in promoting students’ daily PA engagement in and outside of schools.
Recovery of large carnivores in Europe’s modern human-dominated landscapes
Authors: Chapron Guillaume , Kaczensky Petra , Linnell John D. C. , von Arx Manuela , Huber Djuro , Andrén Henrik , López-Bao José Vicente , Adamec Michal , Álvares Francisco , Anders Ole , Balčiauskas Linas , Balys Vaidas , Bedő Péter , Bego Ferdinand , Blanco Juan Carlos , Breitenmoser Urs , Brøseth Henrik , Bufka Luděk , Bunikyte Raimonda , Ciucci Paolo , Dutsov Alexander , Engleder Thomas , Fuxjäger Christian , Groff Claudio , Holmala Katja , Hoxha Bledi , Iliopoulos Yorgos , Ionescu Ovidiu , Jeremić Jasna , Jerina Klemen , Kluth Gesa , Knauer Felix , Kojola Ilpo , Kos Ivan , Krofel Miha , Kubala Jakub , Kunovac Saša , Kusak Josip , Kutal Miroslav , Liberg Olof , Majić Aleksandra , Männil Peep , Manz Ralph , Marboutin Eric , Marucco Francesca , Melovski Dime , Mersini Kujtim , Mertzanis Yorgos , Mysłajek Robert W. , Nowak Sabina , Odden John , Ozolins Janis , Palomero Guillermo , Paunović Milan , Persson Jens , Potočnik Hubert , Quenette Pierre-Yves , Rauer Georg , Reinhardt Ilka , Rigg Robin , Ryser Andreas , Salvatori Valeria , Skrbinšek Tomaž , Stojanov Aleksandar , Swenson Jon E. , Szemethy László , Trajçe Aleksandër , Tsingarska-Sedefcheva Elena , Váňa Martin , Veeroja Rauno , Wabakken Petter , Wölfl Manfred , Wölfl Sybille , Zimmermann Fridolin , Zlatanova Diana , Boitani Luigi
Published: December 2014

The conservation of large carnivores is a formidable challenge for biodiversity conservation. Using a data set on the past and current status of brown bears (Ursus arctos), Eurasian lynx (Lynx lynx), gray wolves (Canis lupus), and wolverines (Gulo gulo) in European countries, we show that roughly one-third of mainland Europe hosts at least one large carnivore species, with stable or increasing abundance in most cases in 21st-century records. The reasons for this overall conservation success include protective legislation, supportive public opinion, and a variety of practices making coexistence between large carnivores and people possible. The European situation reveals that large carnivores and people can share the same landscape.
Element-specific anisotropic growth of shaped platinum alloy nanocrystals
Authors: Gan Lin , Cui Chunhua , Heggen Marc , Dionigi Fabio , Rudi Stefan , Strasser Peter
Published: December 2014

Morphological shape in chemistry and biology owes its existence to anisotropic growth and is closely coupled to distinct functionality. Although much is known about the principal growth mechanisms of monometallic shaped nanocrystals, the anisotropic growth of shaped alloy nanocrystals is still poorly understood. Using aberration-corrected scanning transmission electron microscopy, we reveal an element-specific anisotropic growth mechanism of platinum (Pt) bimetallic nano-octahedra where compositional anisotropy couples to geometric anisotropy. A Pt-rich phase evolves into precursor nanohexapods, followed by a slower step-induced deposition of an M-rich (M = Ni, Co, etc.) phase at the concave hexapod surface forming the octahedral facets. Our finding explains earlier reports on unusual compositional segregations and chemical degradation pathways of bimetallic polyhedral catalysts and may aid rational synthesis of shaped alloy catalysts with desired compositional patterns and properties.
Access to medicines by child refugees in the East Midlands region of England: a cross-sectional study
Authors: Alkahtani S , Cherrill J , Millward C , Grayson K , Hilliam R , Sammons H , Choonara I
Published: December 2014

Objectives

To explore access to primary healthcare and drug therapy by refugee children in the East Midlands region of England.

Design

Interviews with refugees with children and a control group of British parents with children.

Setting

East Midlands region of England.

Participants

50 refugees with children and a control group of 50 parents with children.

Main outcome measures

Number of medicines used by children in the last month and the past 6 months. Health of parents and children. Registration with a general practitioner (GP).

Results

All families in both groups were registered with a GP. There was no difference in the number of children in the two groups experiencing illnesses .In the last month, 30 refugee children received 60 medicines and 31 control children 63 medicines. In the past 6 months, 48 refugee children received 108 medicines and 43 control children 96 medicines. There was no difference between the two groups of children in relation to the likelihood of receiving any medicines in either the last month (P=0.839) or the past 6 months (p=0.81). Children in the refugee group were more likely to receive prescribed medicines for the last month (p=0.008) and the past 6 months (p<0.001). They were also less likely to receive over the counter (OTC) medicines in the past 6 months (p=0.009).

Conclusions

The refugee children in this study in the East Midlands had access to primary healthcare, medicines and a family doctor. They were more likely to receive prescribed medicines and less likely to receive OTC medicines, especially paracetamol.
Acute effects of an arginine-based supplement on neuromuscular, ventilatory, and metabolic fatigue thresholds during cycle ergometry
Authors: Zak Roksana B. , Camic Clayton L. , Hill Ethan C. , Monaghan Molly M. , Kovacs Attila J. , Wright Glenn A.
Published: December 2014

The purpose of the present study was to examine the effects of an acute dose of an arginine-based supplement on the physical working capacity at the fatigue threshold (PWCFT), lactate threshold (LT), ventilatory threshold (VT), and peak oxygen uptake during incremental cycle ergometry. This study used a double-blinded, placebo-controlled, within-subjects crossover design. Nineteen untrained men (mean age ± SD = 22.0 ± 1.7 years) were randomly assigned to ingest either the supplement (3.0 g of arginine, 300 mg of grape seed extract, and 300 mg of polyethylene glycol) or placebo (microcrystalline cellulose) and performed an incremental test on a cycle ergometer for determination of PWCFT, LT, VT, and peak oxygen uptake. Following a 1-week period, the subjects returned to the laboratory and ingested the opposite substance (either supplement or placebo) prior to completing another incremental test to be reassessed for PWCFT, LT, VT, and peak oxygen uptake. The paired-samples t tests indicated there were significant (P < 0.05) mean differences between the arginine and placebo conditions for the PWCFT (192 ± 42 vs. 168 ± 53 W, respectively) and VT (2546 ± 313 vs. 2452 ± 342 mL·min−1), but not the LT (135 ± 26 vs. 138 ± 22 W), absolute peak oxygen uptake (3663 ± 445 vs. 3645 ± 438 mL·min−1), or relative peak oxygen uptake (46.5 ± 6.0 vs. 46.2 ± 5.0 mL·kg−1·min−1). These findings suggested that the arginine-based supplement may be used on an acute basis for delaying the onset of neuromuscular fatigue (i.e., PWCFT) and improving the VT in untrained individuals.
Studies on the flowering biology of red sorrel (Rumex acetosella) ramets from lowbush blueberry (Vaccinium angustifolium) fields in Nova Scotia, Canada
Authors: White Scott N. , Boyd Nathan S. , Van Acker Rene C. , Swanton Clarence J.
Published: December 2014

Red sorrel (Rumex acetosella L.) is a ramet-producing herbaceous creeping perennial species commonly found as a weed in commercially managed lowbush blueberry (Vaccinium angustifolium Aiton) fields in Nova Scotia, Canada. Flowering and seed production occur primarily in overwintering ramets of this species, indicating a potential vernalization requirement for flowering. This study was therefore initiated to examine the role of vernalization, photoperiod, and pre-vernalization stimulus on ramet flowering. Red sorrel ramets propagated from creeping roots and seeds collected from established red sorrel populations in lowbush blueberry had an obligate requirement for vernalization to flower. Ramet populations maintained under pre- and post-vernalization photoperiods of 16 h flowered following 12 weeks of vernalization at 4 ± 0.1 °C, whereas those maintained under constant 16, 14, or 8 h photoperiods without vernalization did not flower. Vernalization for 10 weeks maximized, but did not saturate, the flowering response. Pre-vernalization photoperiod affected flowering response, with increased flowering frequency observed in ramet populations exposed to decreasing, rather than constant, photoperiod prior to vernalization. This study represents the first attempt to determine the combined effects of vernalization and photoperiod on red sorrel flowering, and the results provide a benchmark for the future study of flowering and sexual reproduction in this economically important perennial weed species.
Multivariate analysis of isolated tyrannosaurid teeth from the Danek Bonebed, Horseshoe Canyon Formation, Alberta, Canada
Authors: Torices Angelica , Reichel Miriam , Currie Philip J.
Published: December 2014

A significant number of fossil remains of the hadrosaurid Edmontosaurus have been recovered from the Danek Bonebed (Horseshoe Canyon Formation, Upper Cretaceous, Alberta). Bones from theropod dinosaurs are scarce in this hadrosaur-dominated bonebed, but more than 60 tyrannosaurid theropod teeth have been found. The isolated tyrannosaurid teeth include juvenile and adult specimens, although the precise ontogenetic stage has not been determined. The use of multivariate analyses helps determine the variance of the sample and verifies the initial taxonomic affinities given to these teeth, showing their high potential as a useful tool to better discriminate tyrannosaurid teeth. It also provides an insight into the tyrannosaurid intraspecific variability in the Horseshoe Canyon Formation.
Assessing the age of the Late Cretaceous Danek Bonebed with U–Pb geochronology
Authors: Davies Joshua H.F.L. , Wotzlaw Jörn-Frederik , Wolfe Alexander P. , Heaman Larry M.
Published: December 2014

An ash-rich volcaniclastic sandstone immediately underlying dinosaur-rich material from the Danek Bonebed in the Horseshoe Canyon Formation (HCF), Edmonton, Alberta, Canada, contains accessory zircon, which have been dated employing U–Pb geochronology. Both laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and chemical abrasion isotope dilution thermal ionization mass spectrometry (ID-TIMS) U–Pb analyses have been conducted. The zircon age distributions are complex with U–Pb dates ranging from Precambrian to Cretaceous. We consider the youngest ID-TIMS 206Pb/238U date of 71.923 ± 0.068 Ma as the maximum deposition age of the ash-rich sandstone, placing the overlying Danek bonebed in the early Maastrichtian. This age is compatible with the paleontological assemblage from the Danek Bonebed and the regional stratigraphy. The zircon age distribution also implies that the HCF had a complex provenance of the detritus with some Archean and Proterozoic zircons, a group of Mesozoic, and a large compliment of Cretaceous grains. The results highlight the importance of high precision geochronology in constraining the age of important fossil deposits such as the Danek Bonebed.
Evaluating the transition to sustainable forest management in Ontario’s Crown Forest Sustainability Act and forest management planning manuals from 1994 to 2009
Authors: Robson Mark , Davis Troy
Published: December 2014

The purpose of the paper is to analyse the extent of policy change and learning in the 20 years following the implementation of Ontario’s forest sustainability legislation. Extent of policy learning and change towards sustainable forest management are measured using a combination of content, co-occurrence, and textual analysis of the previous Crown Timber Act and the new Crown Forest Sustainability Act, as well as the latter’s 1996 and 2009 forest planning manuals. There were four key findings. First, policy change towards sustainable forest management has been limited. Second, although there was an increased number of values mentioned in new legislation and planning manuals, the frequency of timber values remained dominant. Third, although integration occurred among a greater range of values, integration with timber values continued to dominate. Fourth, with respect to policy learning, the achievement of sustainable forest management is now explicit and judged based on evidence regarding the inclusion of a range of values beyond timber. The paper concludes that the transition to the more integrative and responsive policies of sustainable forest management remains a work in progress.
A role of Candida albicans CDC4 in the negative regulation of biofilm formation
Authors: Tseng Tzu-Ling , Lai Wei-Chung , Lee Tai-Lin , Hsu Wan Hua , Sun Yu Wen , Li Wan Chen , Cheng Chun-Wen , Shieh Jia-Ching
Published: December 2014

The CDC4 gene is nonessential in Candida albicans and plays a role in suppressing filamentous growth, in contrast to its homologues, which are involved in the G1–S transition of the cell cycle. While characterizing the function of C. albicans CDC4 (CaCDC4), we found that the loss of CaCDC4 resulted in a reduction in cell flocculation, indicating a possible role for CaCDC4 in biofilm formation. To elucidate the role of CaCDC4 in biofilm formation, Cacdc4 null mutant strains were constructed by using the mini-Ura-blaster method. To create a CaCDC4 rescued strain, the plasmid p6HF-ACT1p-CaCDC4 capable of constitutively expressing CaCDC4 was introduced into the Cacdc4 homozygous null mutant. To determine the biofilm formation ability, an in vitro XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium-5-carboxanilide) reduction assay was used. Compared with the parental auxotrophic strain BWP17, the Cacdc4 homozygous null mutant was able to enhance biofilm formation significantly. This enhancement of biofilm formation in the Cacdc4 homozygous null mutant could be reversed by constitutively expressing CaCDC4. We conclude that CaCDC4 has a role in suppressing biofilm formation in C. albicans.
Approximating metal–insulator transitions
Authors: Danieli Carlo , Rayanov Kristian , Pavlov Boris , Martin Gaven , Flach Sergej
Published: December 2014

We consider quantum wave propagation in one-dimensional quasiperiodic lattices. We propose an iterative construction of quasiperiodic potentials from sequences of potentials with increasing spatial period. At each finite iteration step, the eigenstates reflect the properties of the limiting quasiperiodic potential properties up to a controlled maximum system size. We then observe approximate Metal–Insulator Transitions (MIT) at the finite iteration steps. We also report evidence on mobility edges, which are at variance to the celebrated Aubry–André model. The dynamics near the MIT shows a critical slowing down of the ballistic group velocity in the metallic phase, similar to the divergence of the localization length in the insulating phase.
Quantum effects in topological and Schwarzschild de Sitter brane: Aspects of torsion on $(D\!{\bar D})_4$-brane
Authors: Kapoor Richa , Kar Supriya , Singh Deobrat
Published: December 2014

We investigate an effective torsion curvature in a second-order formalism underlying a two-form world-volume dynamics in a D5-brane. In particular, we consider the two form in presence of a background (open string) metric in a U(1) gauge theory. Interestingly the formalism may be viewed via a noncoincident pair of [Formula: see text]-brane with a global Nereu–Schwarz (NS) two form on an anti-brane and a local two form on a brane. The energy–momentum tensor is computed in the six-dimensional (6D) conformal field theory (CFT). It is shown to source a metric fluctuation on a vacuum created pair of [Formula: see text]-brane at a cosmological horizon by the two-form quanta in the gauge theory. The emergent gravity scenario is shown to describe a low-energy (perturbative) string vacuum in 6D with a nonperturbative (NP) quantum correction by a lower (p < 5) dimensional Dp-brane or an anti-brane in the formalism. A closed string exchange between a pair of [Formula: see text]-brane, underlying a closed/open string duality, is argued to describe the Einstein vacuum in a low-energy limit. We obtain topological de Sitter (TdS) and Schwarzschild brane universe in six dimensions. The brane/anti-brane geometries are analyzed to explore some of their characteristic and thermal behaviors in presence of the quantum effects. They reveal an underlying nine-dimensional type IIA and IIB superstring theories on S1.
Lowness for effective Hausdorff dimension
Authors: Lempp Steffen , Miller Joseph S. , Ng Keng Meng , Turetsky Daniel D. , Weber Rebecca
Published: December 2014

We examine the sequences A that are low for dimension, i.e. those for which the effective (Hausdorff) dimension relative to A is the same as the unrelativized effective dimension. Lowness for dimension is a weakening of lowness for randomness, a central notion in effective randomness. By considering analogues of characterizations of lowness for randomness, we show that lowness for dimension can be characterized in several ways. It is equivalent to lowishness for randomness, namely, that every Martin-Löf random sequence has effective dimension 1 relative to A, and lowishness for K, namely, that the limit of KA(n)/K(n) is 1. We show that there is a perfect [Formula: see text]-class of low for dimension sequences. Since there are only countably many low for random sequences, many more sequences are low for dimension. Finally, we prove that every low for dimension is jump-traceable in order nε, for any ε > 0.
MUSCLES IMPULSES USING TOP-LOADER TYPE OF WASHING MACHINE WITH DIFFERENT ENTRANCE HEIGHTS AND DRUM DEPTHS
Authors: CHO YOUNG-KUEN , KIM SEONG GUK , LIM DOHYUNG , KIM DONG HYUN , KIM HAN SUNG , KO CHANG-YONG
Published: December 2014

This study was conducted to evaluate impulses in muscles during washing using top-loader type of washing machine and to predict the risk of musculoskeletal disorders. Experimental and virtual three-dimensional motion analyses were performed repeatedly with six healthy females using a top-loader type of washing machine at different entrance heights and drum depths. We calculated impulses of muscles from the motion data. Impulses of the latissimus dorsi and erector spinae muscles were the highest of those in the muscles.
Symmetry analysis of the Klein–Gordon equation in Bianchi I spacetimes
Authors: Paliathanasis A. , Tsamparlis M. , Mustafa M. T.
Published: December 2014

In this work we perform the symmetry classification of the Klein–Gordon equation in Bianchi I spacetime. We apply a geometric method which relates the Lie symmetries of the Klein–Gordon equation with the conformal algebra of the underlying geometry. Furthermore, we prove that the Lie symmetries which follow from the conformal algebra are also Noether symmetries for the Klein–Gordon equation. We use these results in order to determine all the potentials in which the Klein–Gordon admits Lie and Noether symmetries. Due to the large number of cases and for easy reference the results are presented in the form of tables. For some of the potentials we use the Lie admitted symmetries to determine the corresponding invariant solution of the Klein–Gordon equation. Finally, we show that the results also solve the problem of classification of Lie/Noether point symmetries of the wave equation in Bianchi I spacetime and can be used for the determination of invariant solutions of the wave equation.
The Ehlers–Geroch theorem on geodesic motion in general relativity
Authors: Bezares Miguel , Palomera Gonzalo , Pons Daniel J. , Reyes Enrique G.
Published: December 2014

We provide a detailed and rigorous proof of (a generalized version of) the Ehlers–Geroch theorem on geodesic motion in metric theories of gravity: we assume that (M, g) is a spacetime satisfying an averaged form of the dominant energy condition and some further technical assumptions indicated in the bulk of this paper. Then, a small body which is allowed to deform the original spacetime metric g moves, nonetheless, along a geodesic of (M, g).
A New First-Order Shear Deformation Theory for Free Vibrations of Rectangular Plate
Authors: Xiang Wei , Xing Yufeng
Published: December 2014

A new first-order shear deformation theory (FSDT) with pure bending deflection and shearing deflection as two independent variables is presented in this paper for free vibrations of rectangular plate. In this two-variable theory, the shearing deflection is regarded as the only fundamental variable by which the total deflection and bending deflection can be expressed explicitly. In contrast with the conventional three-variable first-order shear plate theory, present variationally consistent theory derived by using Hamiltonian variational principle can uniquely define the bending and the shearing deflections, and give two rotations by the differentiations of bending deflection. Due to more restrictive geometrical constraints on rotations and boundary conditions, the obtained natural frequencies are equal to or higher than those by conventional FSDT for the rectangular plate with at least one pair of opposite edges simply supported. This new theory is of considerable significance in theoretical sense for giving a simple two-variable FSDT which is variational consistent and involve rotary inertia and shear deformation. The relation and differences of present theory with conventional FSDT and other relative formulations are discussed in detail.
A simplified constitutive model for predicting shape memory polymers deformation behavior
Authors: Li Yunxin , Guo Siu-Siu , He Yuhao , Liu Zishun
Published: December 2014

Shape memory polymers (SMPs) can keep a temporary shape after pre-deformation at a higher temperature and subsequent cooling. When they are reheated, their original shapes can be recovered. Such special characteristics of SMPs make them widely used in aerospace structures, biomedical devices, functional textiles and other devices. Increasing usefulness of SMPs motivates us to further understand their thermomechanical properties and deformation behavior, of which the development of appropriate constitutive models for SMPs is imperative. There is much work in literatures that address constitutive models of the thermo-mechanical coupling in SMPs. However, due to their complex forms, it is difficult to apply these constitutive models in the real world. In this paper, a three-element model with simple form is proposed to investigate the thermo-mechanical small strain (within 10%) behavior of polyurethane under uniaxial tension. Two different cases of heated recovery are considered: (1) unconstrained free strain recovery and (2) stress recovery under full constraint at a strain level fixed during low temperature unloading. To validate the model, simulated and predicted results are compared with Tobushi's experimental results and good agreement can be observed.
Fatigue-related firing of muscle nociceptors reduces voluntary activation of ipsilateral but not contralateral lower limb muscles
Authors: Kennedy David S. , Fitzpatrick Siobhan C. , Gandevia Simon C. , Taylor Janet L.
Published: December 2014

During fatiguing upper limb exercise, maintained firing of group III/IV muscle afferents can limit voluntary drive to muscles within the same limb. It is not known if this effect occurs in the lower limb. We investigated the effects of group III/IV muscle afferent firing from fatigued ipsilateral and contralateral extensor muscles and ipsilateral flexor muscles of the knee on voluntary activation of the knee extensors. In three experiments, we examined voluntary activation of the knee extensors by measuring changes in superimposed twitches evoked by femoral nerve stimulation. Subjects attended on 2 days for each experiment. On one day a sphygmomanometer cuff occluded blood flow of the fatigued muscles to maintain firing of group III/IV muscle afferents. After a 2-min extensor contraction ( experiment 1; n = 9), mean voluntary activation was lower with than without maintained ischemia (47 ± 19% vs. 87 ± 8%, respectively; P < 0.001). After a 2-min knee flexor maximal voluntary contraction (MVC) ( experiment 2; n = 8), mean voluntary activation was also lower with than without ischemia (59 ± 21% vs. 79 ± 9%; P < 0.01). After the contralateral (left) MVC ( experiment 3; n = 8), mean voluntary activation of the right leg was similar with or without ischemia (92 ± 6% vs. 93 ± 4%; P = 0.65). After fatiguing exercise, activity in group III/IV muscle afferents reduces voluntary activation of the fatigued muscle and nonfatigued antagonist muscles in the same leg. However, group III/IV muscle afferents from the fatigued left leg had no effect on the unfatigued right leg. This suggests that any “crossover” of central fatigue in the lower limbs is not mediated by group III/IV muscle afferents.
Increased hepcidin levels in high-altitude pulmonary edema
Authors: Altamura Sandro , Bärtsch Peter , Dehnert Christoph , Maggiorini Marco , Weiss Günter , Theurl Igor , Muckenthaler Martina U. , Mairbäurl Heimo
Published: December 2014

Low iron availability enhances hypoxic pulmonary vasoconstriction (HPV). Considering that reduced serum iron is caused by increased erythropoiesis, insufficient reabsorption, or elevated hepcidin levels, one might speculate that exaggerated HPV in high-altitude pulmonary edema (HAPE) is related to low serum iron. To test this notion we measured serum iron and hepcidin in blood samples obtained in previously published studies at low altitude and during 2 days at 4,559 m (HA1, HA2) from controls, individuals with HAPE, and HAPE-susceptible individuals where prophylactic dexamethasone and tadalafil prevented HAPE. As reported, at 4,559 m pulmonary arterial pressure was increased in healthy volunteers but reached higher levels in HAPE. Serum iron levels were reduced in all groups at HA2. Hepcidin levels were reduced in all groups at HA1 and HA2 except in HAPE, where hepcidin was decreased at HA1 but unexpectedly high at HA2. Elevated hepcidin in HAPE correlated with increased IL-6 at HA2, suggesting that an inflammatory response related to HAPE contributes to increased hepcidin. Likewise, platelet-derived growth factor, a regulator of hepcidin, was increased at HA1 and HA2 in controls but not in HAPE, suggesting that hypoxia-controlled factors that regulate serum iron are inappropriately expressed in HAPE. In summary, we found that HAPE is associated with inappropriate expression of hepcidin without inducing expected changes in serum iron within 2 days at HA, likely due to too short time. Although hepcidin expression is uncoupled from serum iron availability and hypoxia in individuals developing HAPE, our findings indicate that serum iron is not related with exaggerated HPV.
Effect of the Carbon Concentration, Blend Concentration, and Renewal Rate in the Growth Kinetic ofChlorellasp.
Authors: Henrard Adriano Arruda , Rosa Gabriel Martins da , Moraes Luiza , Morais Michele Greque de , Costa Jorge Alberto Vieira
Published: December 2014

The microalgae cultivation can be used as alternative sources of food, in agriculture, residual water treatment, and biofuels production. Semicontinuous cultivation is little studied but is more cost-effective than the discontinuous (batch) cultivation. In the semicontinuous cultivation, the microalga is maintained in better concentration of nutrients and the photoinhibition by excessive cell is reduced. Thus, biomass productivity and biocompounds of interest, such as lipid productivity, may be higher than in batch cultivation. The objective of this study was to examine the influence of blend concentration, medium renewal rate, and concentration of sodium bicarbonate on the growth ofChlorellasp. during semicontinuous cultivation. The cultivation was carried out in Raceway type bioreactors of 6 L, for 40 d at 30°C, 41.6 µmol m−2 s−1, and a 12 h light/dark photoperiod. Maximum specific growth rate (0.149 d−1) and generating biomass (2.89 g L−1) were obtained when the blend concentration was 0.80 g L−1, the medium renewal rate was 40%, and NaHCO3was 1.60 g L−1. The average productivity (0.091 g L−1 d−1) was achieved with 0.8 g L−1of blend concentration and NaHCO3concentration of 1.6 g L−1, independent of the medium renewal rate.
Mild Adrenal Steroidogenic Defects and ACTH-Dependent Aldosterone Secretion in High Blood Pressure: Preliminary Evidence
Authors: Martin Martins João , do Vale Sónia , Martins Ana Filipa
Published: December 2014

Introduction. Adrenal glands play a major role in the control of blood pressure and mild defects of steroidogenesis and/or inappropriate control of mineralocorticoid production have been reported in high blood pressure (HBP).Patients and Methods. We used a specific protocol for the evaluation of 100 consecutive patients with inappropriate or recent onset HBP. Specific methods were used to confirm HBP and to diagnose secondary forms of HBP. In addition we tested adrenal steroidogenesis with the common cosyntropin test, modified to include the simultaneous measurement of renin and aldosterone besides 17-hydroxyprogesterone (17OHP) and 11-deoxycortisol (S).Results. Secondary forms of HBP were diagnosed in 32 patients, including 14 patients with primary hyperaldosteronism (PA) (14%) and 10 patients with pheochromocytoma (10%). Mild defects of the 21-hydroxylase (21OHD) and 11-hydroxylase (11OHD) enzymes were common (42%). ACTH-dependent aldosterone secretion was found in most patients (54%) and characteristically in those with mild defects of adrenal steroidogenesis (>60%), PA (>75%), and otherwise in patients with apparent essential HBP (EHBP) (32%).Discussion. Mild defects of adrenal steroidogenesis are common in patients with HBP, occurring in almost half of the patients. In those patients as well as in patients with apparent EHBP, aldosterone secretion is commonly dependent on ACTH.
Isolated Bilateral Renal Mucormycosis Masquerading as Renal Abscess in an Immunocompetent Individual: A Lesson Learnt
Authors: Paonam Somorendro , Bag Sananda , Mavuduru Ravimohan S. , Agarwal Mayank Mohan , Mandal Arup Kumar
Published: December 2014

Isolated renal mucormycosis is a rare entity in immunocompetent subjects. It is usually a rapidly progressive disease with poor prognosis but it can mimic renal abscess with a protracted course.
Not Always Asthma: Clinical and Legal Consequences of Delayed Diagnosis of Laryngotracheal Stenosis
Authors: Nunn Adam C. , Nouraei S. Ali R. , George P. Jeremy , Sandhu Guri S. , Nouraei S. A. Reza
Published: December 2014

Laryngotracheal stenosis (LTS) is a rare condition that occurs most commonly as a result of instrumentation of the airway but may also occur as a result of inflammatory conditions or idiopathically. Here, we present the case of a patient who developed LTS as a complication of granulomatosis with polyangiitis (GPA), which was misdiagnosed as asthma for 6 years. After an admission with respiratory symptoms that worsened to the extent that she required intubation, a previously well 14-year-old girl was diagnosed with GPA. Following immunosuppressive therapy, she made a good recovery and was discharged after 22 days. Over subsequent years, she developed dyspnoea and “wheeze” and a diagnosis of asthma was made. When she became pregnant, she was admitted to hospital with worsening respiratory symptoms, whereupon her “wheeze” was correctly identified as “stridor,” and subsequent investigations revealed a significant subglottic stenosis. The delay in diagnosis precluded the use of minimally invasive therapies, with the result that intermittent laser resection and open laryngotracheal reconstructive surgery were the only available treatment options. There were numerous points at which the correct diagnosis might have been made, either by proper interpretation of flow-volume loops or by calculation of the Empey or Expiratory Disproportion Indices from spirometry data.