Control system and method for a power delivery system having a continuously variable ratio transmission

DOEpatents

Frank, A.A.

1984-07-10

A control system and method for a power delivery system, such as in an automotive vehicle, having an engine coupled to a continuously variable ratio transmission (CVT). Totally independent control of engine and transmission enable the engine to precisely follow a desired operating characteristic, such as the ideal operating line for minimum fuel consumption. CVT ratio is controlled as a function of commanded power or torque and measured load, while engine fuel requirements (e.g., throttle position) are strictly a function of measured engine speed. Fuel requirements are therefore precisely adjusted in accordance with the ideal characteristic for any load placed on the engine. 4 figs.

Control approach development for variable recruitment artificial muscles

NASA Astrophysics Data System (ADS)

Jenkins, Tyler E.; Chapman, Edward M.; Bryant, Matthew

2016-04-01

This study characterizes hybrid control approaches for the variable recruitment of fluidic artificial muscles with double acting (antagonistic) actuation. Fluidic artificial muscle actuators have been explored by researchers due to their natural compliance, high force-to-weight ratio, and low cost of fabrication. Previous studies have attempted to improve system efficiency of the actuators through variable recruitment, i.e. using discrete changes in the number of active actuators. While current variable recruitment research utilizes manual valve switching, this paper details the current development of an online variable recruitment control scheme. By continuously controlling applied pressure and discretely controlling the number of active actuators, operation in the lowest possible recruitment state is ensured and working fluid consumption is minimized. Results provide insight into switching control scheme effects on working fluids, fabrication material choices, actuator modeling, and controller development decisions.

Noninvasive health condition monitoring device for workers at high altitudes conditions.

PubMed

Aqueveque, Pablo; Gutierrez, Cristopher; Saavedra, Francisco; Pino, Esteban J

2016-08-01

This work presents the design and implementation of a continuous monitoring device to control the health state of workers, for instance miners, at high altitudes. The extreme ambient conditions are harmful for peoples' health; therefore a continuous control of the workers' vital signs is necessary. The developed system includes physiological variables: electrocardiogram (ECG), respiratory activity and body temperature (BT), and ambient variables: ambient temperature (AT) and relative humidity (RH). The noninvasive sensors are incorporated in a t-shirt to deliver a functional device, and maximum comfort to the users. The device is able to continuously calculate heart rate (HR) and respiration rate (RR), and establish a wireless data transmission to a central monitoring station.

Design study of a continuously variable roller cone traction CVT for electric vehicles

NASA Technical Reports Server (NTRS)

Mccoin, D. K.; Walker, R. D.

1980-01-01

Continuously variable ratio transmissions (CVT) featuring cone and roller traction elements and computerized controls are studied. The CVT meets or exceeds all requirements set forth in the design criteria. Further, a scalability analysis indicates the basic concept is applicable to lower and higher power units, with upward scaling for increased power being more readily accomplished.

Genetic-evolution-based optimization methods for engineering design

NASA Technical Reports Server (NTRS)

Rao, S. S.; Pan, T. S.; Dhingra, A. K.; Venkayya, V. B.; Kumar, V.

1990-01-01

This paper presents the applicability of a biological model, based on genetic evolution, for engineering design optimization. Algorithms embodying the ideas of reproduction, crossover, and mutation are developed and applied to solve different types of structural optimization problems. Both continuous and discrete variable optimization problems are solved. A two-bay truss for maximum fundamental frequency is considered to demonstrate the continuous variable case. The selection of locations of actuators in an actively controlled structure, for minimum energy dissipation, is considered to illustrate the discrete variable case.

Controlling Continuous-Variable Quantum Key Distribution with Entanglement in the Middle Using Tunable Linear Optics Cloning Machines

NASA Astrophysics Data System (ADS)

Wu, Xiao Dong; Chen, Feng; Wu, Xiang Hua; Guo, Ying

2017-02-01

Continuous-variable quantum key distribution (CVQKD) can provide detection efficiency, as compared to discrete-variable quantum key distribution (DVQKD). In this paper, we demonstrate a controllable CVQKD with the entangled source in the middle, contrast to the traditional point-to-point CVQKD where the entanglement source is usually created by one honest party and the Gaussian noise added on the reference partner of the reconciliation is uncontrollable. In order to harmonize the additive noise that originates in the middle to resist the effect of malicious eavesdropper, we propose a controllable CVQKD protocol by performing a tunable linear optics cloning machine (LOCM) at one participant's side, say Alice. Simulation results show that we can achieve the optimal secret key rates by selecting the parameters of the tuned LOCM in the derived regions.

Invited Article: Generation of one-million-mode continuous-variable cluster state by unlimited time-domain multiplexing

NASA Astrophysics Data System (ADS)

Yoshikawa, Jun-ichi; Yokoyama, Shota; Kaji, Toshiyuki; Sornphiphatphong, Chanond; Shiozawa, Yu; Makino, Kenzo; Furusawa, Akira

2016-09-01

In recent quantum optical continuous-variable experiments, the number of fully inseparable light modes has drastically increased by introducing a multiplexing scheme either in the time domain or in the frequency domain. Here, modifying the time-domain multiplexing experiment reported in the work of Yokoyama et al. [Nat. Photonics 7, 982 (2013)], we demonstrate the successive generation of fully inseparable light modes for more than one million modes. The resulting multi-mode state is useful as a dual-rail continuous variable cluster state. We circumvent the previous problem of optical phase drifts, which has limited the number of fully inseparable light modes to around ten thousands, by continuous feedback control of the optical system.

Interesting examples of supervised continuous variable systems

NASA Technical Reports Server (NTRS)

Chase, Christopher; Serrano, Joe; Ramadge, Peter

1990-01-01

The authors analyze two simple deterministic flow models for multiple buffer servers which are examples of the supervision of continuous variable systems by a discrete controller. These systems exhibit what may be regarded as the two extremes of complexity of the closed loop behavior: one is eventually periodic, the other is chaotic. The first example exhibits chaotic behavior that could be characterized statistically. The dual system, the switched server system, exhibits very predictable behavior, which is modeled by a finite state automaton. This research has application to multimodal discrete time systems where the controller can choose from a set of transition maps to implement.

Spool-type control valve assembly with reduced spool stroke for hydraulic belt-and-pulley type continuously variable transmission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Itoh, H.; Akashi, T.; Takada, M.

1987-03-31

This patent describes a hydraulic control system for controlling a speed ratio of a hydraulically-operated continuously variable transmission of belt-and-pulley type having a variable-diameter pulley and a hydraulic cylinder for changing an effective diameter of the variable diameter-pulley of the transmission. The hydraulic control system includes a speed-ratio control valve assembly for controlling the supply and discharge of a pressurized fluid to and from the hydraulic cylinder to thereby change the speed ratio of the transmission. The speed-ratio control valve assembly comprises: a shift-direction switching valve unit disposed in fluid supply and discharge conduits communicating with the hydraulic cylinder, formore » controlling a direction in which the speed ratio of the transmission is varied; a shift-speed control valve unit of spool-valve type connected to the shift-direction switching valve unit. The shift-speed control valve unit is selectively placed in a first state in which the fluid supply and discharge flows to and from the hydraulic cylinder through the conduits are permitted, or in a second state in which the fluid supply flow is restricted while the fluid discharge flow is inhibited; an actuator means for placing the shift speed control valve unit alternately in the first and second states to control a rate of variation in the speed ratio of the transmission in the direction established by the shift-direction switching valve unit.« less

Comparison of a step-down dose of once-daily ciclesonide with a continued dose of twice-daily fluticasone propionate in maintaining control of asthma.

PubMed

Knox, A; Langan, J; Martinot, J-B; Gruss, C; Häfner, D

2007-10-01

To compare a step-down approach in well-controlled asthma patients, as recommended by treatment guidelines, from fluticasone propionate 250 microg twice daily (FP250 BID), or equivalent, to ciclesonide 160 microg once daily (CIC160 OD) with continued FP250 BID treatment. Patients with well-controlled asthma prior to study entry were included in two identical, randomized, double-blind, double-dummy, parallel-group studies. After a 2-week run-in period with FP250 BID, patients were randomized to CIC160 OD (n = 58) or FP250 BID (n = 53) for 12 weeks. Primary endpoints were percentage of days with asthma control, asthma symptom-free days, rescue medication-free days and nocturnal awakening-free days. Secondary endpoints included lung function variables, asthma symptom scores, rescue medication use and asthma exacerbations. Safety variables were also recorded. Patients had >or= 97% of days with asthma control, 98% asthma symptom-free days and 100% of days free from rescue medication use and nocturnal awakenings in both treatment groups (median values). There were no significant between-treatment differences for any of the primary or secondary efficacy variables. Overall, 42 treatment-emergent adverse events (TEAEs) were reported in the CIC160 OD group and 49 TEAEs were reported in the FP250 BID group. There were no clinically relevant changes from baseline in the safety variables in either treatment group. Patients well controlled on FP250 BID, or equivalent, who were stepped down to CIC160 OD, maintained similar asthma control compared with patients who received continued treatment standardized to FP250 BID.

Compact Hybrid Automotive Propulsion System

NASA Technical Reports Server (NTRS)

Lupo, G.

1986-01-01

Power train proposed for experimental vehicle powered by internal combustion engine and electric motor. Intended for front-wheel drive automobile, power train mass produced using existing technology. System includes internal-combustion engine, electric motor, continuously variable transmission, torque converter, differential, and control and adjustment systems for electric motor and transmission. Continuously variable transmission integrated into hydraulic system that also handles power steering and power brakes. Batteries for electric motor mounted elsewhere in vehicle.

Optimal control on hybrid ode systems with application to a tick disease model.

PubMed

Ding, Wandi

2007-10-01

We are considering an optimal control problem for a type of hybrid system involving ordinary differential equations and a discrete time feature. One state variable has dynamics in only one season of the year and has a jump condition to obtain the initial condition for that corresponding season in the next year. The other state variable has continuous dynamics. Given a general objective functional, existence, necessary conditions and uniqueness for an optimal control are established. We apply our approach to a tick-transmitted disease model with age structure in which the tick dynamics changes seasonally while hosts have continuous dynamics. The goal is to maximize disease-free ticks and minimize infected ticks through an optimal control strategy of treatment with acaricide. Numerical examples are given to illustrate the results.

Metrics for glycaemic control - from HbA1c to continuous glucose monitoring.

PubMed

Kovatchev, Boris P

2017-07-01

As intensive treatment to lower levels of HbA 1c characteristically results in an increased risk of hypoglycaemia, patients with diabetes mellitus face a life-long optimization problem to reduce average levels of glycaemia and postprandial hyperglycaemia while simultaneously avoiding hypoglycaemia. This optimization can only be achieved in the context of lowering glucose variability. In this Review, I discuss topics that are related to the assessment, quantification and optimal control of glucose fluctuations in diabetes mellitus. I focus on markers of average glycaemia and the utility and/or shortcomings of HbA 1c as a 'gold-standard' metric of glycaemic control; the notion that glucose variability is characterized by two principal dimensions, amplitude and time; measures of glucose variability that are based on either self-monitoring of blood glucose data or continuous glucose monitoring (CGM); and the control of average glycaemia and glucose variability through the use of pharmacological agents or closed-loop control systems commonly referred to as the 'artificial pancreas'. I conclude that HbA 1c and the various available metrics of glucose variability reflect the management of diabetes mellitus on different timescales, ranging from months (for HbA 1c ) to minutes (for CGM). Comprehensive assessment of the dynamics of glycaemic fluctuations is therefore crucial for providing accurate and complete information to the patient, physician, automated decision-support or artificial-pancreas system.

Correlates of Injury-forced Work Reduction for Massage Therapists and Bodywork Practitioners.

PubMed

Blau, Gary; Monos, Christopher; Boyer, Ed; Davis, Kathleen; Flanagan, Richard; Lopez, Andrea; Tatum, Donna S

2013-01-01

Injury-forced work reduction (IFWR) has been acknowledged as an all-too-common occurrence for massage therapists and bodywork practitioners (M & Bs). However, little prior research has specifically investigated demographic, work attitude, and perceptual correlates of IFWR among M & Bs. To test two hypotheses, H1 and H2. H1 is that the accumulated cost variables set ( e.g., accumulated costs, continuing education costs) will account for a significant amount of IFWR variance beyond control/demographic (e.g., social desirability response bias, gender, years in practice, highest education level) and work attitude/perception variables (e.g., job satisfaction, affective occupation commitment, occupation identification, limited occupation alternatives) sets. H2 is that the two exhaustion variables (i.e., physical exhaustion, work exhaustion) set will account for significant IFWR variance beyond control/demographic, work attitude/perception, and accumulated cost variables sets. An online survey sample of 2,079 complete-data M & Bs was collected. Stepwise regression analysis was used to test the study hypotheses. The research design first controlled for control/demographic (Step1) and work attitude/perception variables sets (Step 2), before then testing for the successive incremental impact of two variable sets, accumulated costs (Step 3) and exhaustion variables (Step 4) for explaining IFWR. RESULTS SUPPORTED BOTH STUDY HYPOTHESES: accumulated cost variables set (H1) and exhaustion variables set (H2) each significantly explained IFWR after the control/demographic and work attitude/perception variables sets. The most important correlate for explaining IFWR was higher physical exhaustion, but work exhaustion was also significant. It is not just physical "wear and tear", but also "mental fatigue", that can lead to IFWR for M & Bs. Being female, having more years in practice, and having higher continuing education costs were also significant correlates of IFWR. Lower overall levels of work exhaustion, physical exhaustion, and IFWR were found in the present sample. However, since both types of exhaustion significantly and positively impact IFWR, taking sufficient time between massages and, if possible, varying one's massage technique to replenish one's physical and mental energy seem important. Failure to take required continuing education units, due to high costs, also increases risk for IFWR. Study limitations and future research issues are discussed.

Optimal placement of actuators and sensors in control augmented structural optimization

NASA Technical Reports Server (NTRS)

Sepulveda, A. E.; Schmit, L. A., Jr.

1990-01-01

A control-augmented structural synthesis methodology is presented in which actuator and sensor placement is treated in terms of (0,1) variables. Structural member sizes and control variables are treated simultaneously as design variables. A multiobjective utopian approach is used to obtain a compromise solution for inherently conflicting objective functions such as strucutal mass control effort and number of actuators. Constraints are imposed on transient displacements, natural frequencies, actuator forces and dynamic stability as well as controllability and observability of the system. The combinatorial aspects of the mixed - (0,1) continuous variable design optimization problem are made tractable by combining approximation concepts with branch and bound techniques. Some numerical results for example problems are presented to illustrate the efficacy of the design procedure set forth.

40 CFR 64.3 - Monitoring design criteria.

Code of Federal Regulations, 2010 CFR

2010-07-01

... that are adequate to ensure the continuing validity of the data. The owner or operator shall consider... and control device operational variability, the reliability and latitude built into the control...

Heart Rate Variability as a Measure of Airport Ramp-Traffic Controllers Workload

NASA Technical Reports Server (NTRS)

Hayashi, Miwa; Dulchinos, Victoria Lee

2016-01-01

Heart Rate Variability (HRV) has been reported to reflect the person's cognitive and emotional stress levels, and may offer an objective measure of human-operator's workload levels, which are recorded continuously and unobtrusively to the task performance. The present paper compares the HRV data collected during a human-in-the-loop simulation of airport ramp-traffic control operations with the controller participants' own verbal self-reporting ratings of their workload.

Laser system refinements to reduce variability in infarct size in the rat photothrombotic stroke model

PubMed Central

Alaverdashvili, Mariam; Paterson, Phyllis G.; Bradley, Michael P.

2015-01-01

Background The rat photothrombotic stroke model can induce brain infarcts with reasonable biological variability. Nevertheless, we observed unexplained high inter-individual variability despite using a rigorous protocol. Of the three major determinants of infarct volume, photosensitive dye concentration and illumination period were strictly controlled, whereas undetected fluctuation in laser power output was suspected to account for the variability. New method The frequently utilized Diode Pumped Solid State (DPSS) lasers emitting 532 nm (green) light can exhibit fluctuations in output power due to temperature and input power alterations. The polarization properties of the Nd:YAG and Nd:YVO4 crystals commonly used in these lasers are another potential source of fluctuation, since one means of controlling output power uses a polarizer with a variable transmission axis. Thus, the properties of DPSS lasers and the relationship between power output and infarct size were explored. Results DPSS laser beam intensity showed considerable variation. Either a polarizer or a variable neutral density filter allowed adjustment of a polarized laser beam to the desired intensity. When the beam was unpolarized, the experimenter was restricted to using a variable neutral density filter. Comparison with existing method(s) Our refined approach includes continuous monitoring of DPSS laser intensity via beam sampling using a pellicle beamsplitter and photodiode sensor. This guarantees the desired beam intensity at the targeted brain area during stroke induction, with the intensity controlled either through a polarizer or variable neutral density filter. Conclusions Continuous monitoring and control of laser beam intensity is critical for ensuring consistent infarct size. PMID:25840363

A Sequential Shifting Algorithm for Variable Rotor Speed Control

NASA Technical Reports Server (NTRS)

Litt, Jonathan S.; Edwards, Jason M.; DeCastro, Jonathan A.

2007-01-01

A proof of concept of a continuously variable rotor speed control methodology for rotorcraft is described. Variable rotor speed is desirable for several reasons including improved maneuverability, agility, and noise reduction. However, it has been difficult to implement because turboshaft engines are designed to operate within a narrow speed band, and a reliable drive train that can provide continuous power over a wide speed range does not exist. The new methodology proposed here is a sequential shifting control for twin-engine rotorcraft that coordinates the disengagement and engagement of the two turboshaft engines in such a way that the rotor speed may vary over a wide range, but the engines remain within their prescribed speed bands and provide continuous torque to the rotor; two multi-speed gearboxes facilitate the wide rotor speed variation. The shifting process begins when one engine slows down and disengages from the transmission by way of a standard freewheeling clutch mechanism; the other engine continues to apply torque to the rotor. Once one engine disengages, its gear shifts, the multi-speed gearbox output shaft speed resynchronizes and it re-engages. This process is then repeated with the other engine. By tailoring the sequential shifting, the rotor may perform large, rapid speed changes smoothly, as demonstrated in several examples. The emphasis of this effort is on the coordination and control aspects for proof of concept. The engines, rotor, and transmission are all simplified linear models, integrated to capture the basic dynamics of the problem.

Resonance: The science behind the art of sonic drilling

NASA Astrophysics Data System (ADS)

Lucon, Peter Andrew

The research presented in this dissertation quantifies the system dynamics and the influence of control variables of a sonic drill system. The investigation began with an initial body of work funded by the Department of Energy under a Small Business Innovative Research Phase I Grant, grant number: DE-FG02-06ER84618, to investigate the feasibility of using sonic drills to drill micro well holes to depths of 1500 feet. The Department of Energy funding enabled feasibility testing using a 750 hp sonic drill owned by Jeffery Barrow, owner of Water Development Co. During the initial feasibility testing, data was measured and recorded at the sonic drill head while the sonic drill penetrated to a depth of 120 feet. To demonstrate feasibility, the system had to be well understood to show that testing of a larger sonic drill could simulate the results of drilling a micro well hole of 2.5 inch diameter. A first-order model of the system was developed that produced counter-intuitive findings that enabled the feasibility of using this method to drill deeper and produce micro-well holes to 1500 feet using sonic drills. Although funding was not continued, the project work continued. This continued work expanded on the sonic drill models by understanding the governing differential equation and solving the boundary value problem, finite difference methods, and finite element methods to determine the significance of the control variables that can affect the sonic drill. Using a design of experiment approach and commercially available software, the significance of the variables to the effectiveness of the drill system were determined. From the significant variables, as well as the real world testing, a control system schematic for a sonic drill was derived and is patent pending. The control system includes sensors, actuators, personal logic controllers, as well as a human machine interface. It was determined that the control system should control the resonant mode and the weight on the bit as the primary two control variables. The sonic drill can also be controlled using feedback from sensors mounted on the sonic drill head, which is the driver for the sonic drill located above ground

Energy storage connection system

DOEpatents

Benedict, Eric L.; Borland, Nicholas P.; Dale, Magdelena; Freeman, Belvin; Kite, Kim A.; Petter, Jeffrey K.; Taylor, Brendan F.

2012-07-03

A power system for connecting a variable voltage power source, such as a power controller, with a plurality of energy storage devices, at least two of which have a different initial voltage than the output voltage of the variable voltage power source. The power system includes a controller that increases the output voltage of the variable voltage power source. When such output voltage is substantially equal to the initial voltage of a first one of the energy storage devices, the controller sends a signal that causes a switch to connect the variable voltage power source with the first one of the energy storage devices. The controller then causes the output voltage of the variable voltage power source to continue increasing. When the output voltage is substantially equal to the initial voltage of a second one of the energy storage devices, the controller sends a signal that causes a switch to connect the variable voltage power source with the second one of the energy storage devices.

Multivariate statistical process control of a continuous pharmaceutical twin-screw granulation and fluid bed drying process.

PubMed

Silva, A F; Sarraguça, M C; Fonteyne, M; Vercruysse, J; De Leersnyder, F; Vanhoorne, V; Bostijn, N; Verstraeten, M; Vervaet, C; Remon, J P; De Beer, T; Lopes, J A

2017-08-07

A multivariate statistical process control (MSPC) strategy was developed for the monitoring of the ConsiGma™-25 continuous tablet manufacturing line. Thirty-five logged variables encompassing three major units, being a twin screw high shear granulator, a fluid bed dryer and a product control unit, were used to monitor the process. The MSPC strategy was based on principal component analysis of data acquired under normal operating conditions using a series of four process runs. Runs with imposed disturbances in the dryer air flow and temperature, in the granulator barrel temperature, speed and liquid mass flow and in the powder dosing unit mass flow were utilized to evaluate the model's monitoring performance. The impact of the imposed deviations to the process continuity was also evaluated using Hotelling's T 2 and Q residuals statistics control charts. The influence of the individual process variables was assessed by analyzing contribution plots at specific time points. Results show that the imposed disturbances were all detected in both control charts. Overall, the MSPC strategy was successfully developed and applied. Additionally, deviations not associated with the imposed changes were detected, mainly in the granulator barrel temperature control. Copyright © 2017 Elsevier B.V. All rights reserved.

Discrete wavelet transform and energy eigen value for rotor bars fault detection in variable speed field-oriented control of induction motor drive.

PubMed

Ameid, Tarek; Menacer, Arezki; Talhaoui, Hicham; Azzoug, Youness

2018-05-03

This paper presents a methodology for the broken rotor bars fault detection is considered when the rotor speed varies continuously and the induction machine is controlled by Field-Oriented Control (FOC). The rotor fault detection is obtained by analyzing a several mechanical and electrical quantities (i.e., rotor speed, stator phase current and output signal of the speed regulator) by the Discrete Wavelet Transform (DWT) in variable speed drives. The severity of the fault is obtained by stored energy calculation for active power signal. Hence, it can be a useful solution as fault indicator. The FOC is implemented in order to preserve a good performance speed control; to compensate the broken rotor bars effect in the mechanical speed and to ensure the operation continuity and to investigate the fault effect in the variable speed. The effectiveness of the technique is evaluated in simulation and in a real-time implementation by using Matlab/Simulink with the real-time interface (RTI) based on dSpace 1104 board. Copyright © 2018. Published by Elsevier Ltd.

Controlling for confounding variables in MS-omics protocol: why modularity matters.

PubMed

Smith, Rob; Ventura, Dan; Prince, John T

2014-09-01

As the field of bioinformatics research continues to grow, more and more novel techniques are proposed to meet new challenges and improvements upon solutions to long-standing problems. These include data processing techniques and wet lab protocol techniques. Although the literature is consistently thorough in experimental detail and variable-controlling rigor for wet lab protocol techniques, bioinformatics techniques tend to be less described and less controlled. As the validation or rejection of hypotheses rests on the experiment's ability to isolate and measure a variable of interest, we urge the importance of reducing confounding variables in bioinformatics techniques during mass spectrometry experimentation. © The Author 2013. Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

A Mission-Adaptive Variable Camber Flap Control System to Optimize High Lift and Cruise Lift-to-Drag Ratios of Future N+3 Transport Aircraft

NASA Technical Reports Server (NTRS)

Urnes, James, Sr.; Nguyen, Nhan; Ippolito, Corey; Totah, Joseph; Trinh, Khanh; Ting, Eric

2013-01-01

Boeing and NASA are conducting a joint study program to design a wing flap system that will provide mission-adaptive lift and drag performance for future transport aircraft having light-weight, flexible wings. This Variable Camber Continuous Trailing Edge Flap (VCCTEF) system offers a lighter-weight lift control system having two performance objectives: (1) an efficient high lift capability for take-off and landing, and (2) reduction in cruise drag through control of the twist shape of the flexible wing. This control system during cruise will command varying flap settings along the span of the wing in order to establish an optimum wing twist for the current gross weight and cruise flight condition, and continue to change the wing twist as the aircraft changes gross weight and cruise conditions for each mission segment. Design weight of the flap control system is being minimized through use of light-weight shape memory alloy (SMA) actuation augmented with electric actuators. The VCCTEF program is developing better lift and drag performance of flexible wing transports with the further benefits of lighter-weight actuation and less drag using the variable camber shape of the flap.

Hybrid Methods in Quantum Information

NASA Astrophysics Data System (ADS)

Marshall, Kevin

Today, the potential power of quantum information processing comes as no surprise to physicist or science-fiction writer alike. However, the grand promises of this field remain unrealized, despite significant strides forward, due to the inherent difficulties of manipulating quantum systems. Simply put, it turns out that it is incredibly difficult to interact, in a controllable way, with the quantum realm when we seem to live our day to day lives in a classical world. In an effort to solve this challenge, people are exploring a variety of different physical platforms, each with their strengths and weaknesses, in hopes of developing new experimental methods that one day might allow us to control a quantum system. One path forward rests in combining different quantum systems in novel ways to exploit the benefits of different systems while circumventing their respective weaknesses. In particular, quantum systems come in two different flavours: either discrete-variable systems or continuous-variable ones. The field of hybrid quantum information seeks to combine these systems, in clever ways, to help overcome the challenges blocking the path between what is theoretically possible and what is achievable in a laboratory. In this thesis we explore four topics in the context of hybrid methods in quantum information, in an effort to contribute to the resolution of existing challenges and to stimulate new avenues of research. First, we explore the manipulation of a continuous-variable quantum system consisting of phonons in a linear chain of trapped ions where we use the discretized internal levels to mediate interactions. Using our proposed interaction we are able to implement, for example, the acoustic equivalent of a beam splitter with modest experimental resources. Next we propose an experimentally feasible implementation of the cubic phase gate, a primitive non-Gaussian gate required for universal continuous-variable quantum computation, based off sequential photon subtraction. We then discuss the notion of embedding a finite dimensional state into a continuous-variable system, and propose a method of performing quantum computations on encrypted continuous-variable states. This protocol allows for a client, of limited quantum ability, to outsource a computation while hiding their information. Next, we discuss the possibility of performing universal quantum computation on discrete-variable logical states encoded in mixed continuous-variable quantum states. Finally, we present an account of open problems related to our results, and possible future avenues of research.

Coherent attacking continuous-variable quantum key distribution with entanglement in the middle

NASA Astrophysics Data System (ADS)

Zhang, Zhaoyuan; Shi, Ronghua; Zeng, Guihua; Guo, Ying

2018-06-01

We suggest an approach on the coherent attack of continuous-variable quantum key distribution (CVQKD) with an untrusted entangled source in the middle. The coherent attack strategy can be performed on the double links of quantum system, enabling the eavesdropper to steal more information from the proposed scheme using the entanglement correlation. Numeric simulation results show the improved performance of the attacked CVQKD system in terms of the derived secret key rate with the controllable parameters maximizing the stolen information.

A Simple Composite Metric for the Assessment of Glycemic Status from Continuous Glucose Monitoring Data: Implications for Clinical Practice and the Artificial Pancreas.

PubMed

Hirsch, Irl B; Balo, Andrew K; Sayer, Kevin; Garcia, Arturo; Buckingham, Bruce A; Peyser, Thomas A

2017-06-01

The potential clinical benefits of continuous glucose monitoring (CGM) have been recognized for many years, but CGM is used by a small fraction of patients with diabetes. One obstacle to greater use of the technology is the lack of simplified tools for assessing glycemic control from CGM data without complicated visual displays of data. We developed a simple new metric, the personal glycemic state (PGS), to assess glycemic control solely from continuous glucose monitoring data. PGS is a composite index that assesses four domains of glycemic control: mean glucose, glycemic variability, time in range and frequency and severity of hypoglycemia. The metric was applied to data from six clinical studies for the G4 Platinum continuous glucose monitoring system (Dexcom, San Diego, CA). The PGS was also applied to data from a study of artificial pancreas comparing results from open loop and closed loop in adolescents and in adults. The new metric for glycemic control, PGS, was able to characterize the quality of glycemic control in a wide range of study subjects with various mean glucose, minimal, moderate, and excessive glycemic variability and subjects on open loop versus closed loop control. A new composite metric for the assessment of glycemic control based on CGM data has been defined for use in assessing glycemic control in clinical practice and research settings. The new metric may help rapidly identify problems in glycemic control and may assist with optimizing diabetes therapy during time-constrained physician office visits.

Near-optimal, asymptotic tracking in control problems involving state-variable inequality constraints

NASA Technical Reports Server (NTRS)

Markopoulos, N.; Calise, A. J.

1993-01-01

The class of all piecewise time-continuous controllers tracking a given hypersurface in the state space of a dynamical system can be split by the present transformation technique into two disjoint classes; while the first of these contains all controllers which track the hypersurface in finite time, the second contains all controllers that track the hypersurface asymptotically. On this basis, a reformulation is presented for optimal control problems involving state-variable inequality constraints. If the state constraint is regarded as 'soft', there may exist controllers which are asymptotic, two-sided, and able to yield the optimal value of the performance index.

Sex-Role Ideology and the Aspirations of High School Girls

ERIC Educational Resources Information Center

Gaskell, Jane

1977-01-01

Variables specifically related to sex-role definitions in our society must be considered in accounting for the generally lower aspirations of women since after controlling the variables of social class and academic achievement, sex continues to make a difference in the aspiration levels of high school girls. (MJB)

Lack of difference between continuous versus intermittent heparin infusion on maintenance of intra-arterial catheter in postoperative pediatric surgery: a randomized controlled study

PubMed Central

Witkowski, Maria Carolina; de Moraes, Maria Antonieta P.; Firpo, Cora Maria F.

2013-01-01

OBJECTIVE: To compare two systems of arterial catheters maintenance in postoperative pediatric surgery using intermittent or continuous infusion of heparin solution and to analyze adverse events related to the site of catheter insertion and the volume of infused heparin solution. METHODS: Randomized control trial with 140 patients selected for continuous infusion group (CIG) and intermittent infusion group (IIG). The variables analyzed were: type of heart disease, permanence time and size of the catheter, insertion site, technique used, volume of heparin solution and adverse events. The descriptive variables were analyzed by Student's t-test and the categorical variables, by chi-square test, being significant p<0.05. RESULTS: The median age was 11 (0-22) months, and 77 (55%) were females. No significant differences between studied variables were found, except for the volume used in CIG (12.0±1.2mL/24 hours) when compared to IIG (5.3±3.5mL/24 hours) with p<0.0003. CONCLUSIONS: The continuous infusion system and the intermittent infusion of heparin solution can be used for intra-arterial catheters maintenance in postoperative pediatric surgery, regardless of patient's clinical and demographic characteristics. Adverse events up to the third postoperative day occurred similarly in both groups. However, the intermittent infusion system usage in underweight children should be considered, due to the lower volume of infused heparin solution [ClinicalTrials.gov Identifier: NCT01097031]. PMID:24473958

Recent experience in simultaneous control-structure optimization

NASA Technical Reports Server (NTRS)

Salama, M.; Ramaker, R.; Milman, M.

1989-01-01

To show the feasibility of simultaneous optimization as design procedure, low order problems were used in conjunction with simple control formulations. The numerical results indicate that simultaneous optimization is not only feasible, but also advantageous. Such advantages come at the expense of introducing complexities beyond those encountered in structure optimization alone, or control optimization alone. Examples include: larger design parameter space, optimization may combine continuous and combinatoric variables, and the combined objective function may be nonconvex. Future extensions to include large order problems, more complex objective functions and constraints, and more sophisticated control formulations will require further research to ensure that the additional complexities do not outweigh the advantages of simultaneous optimization. Some areas requiring more efficient tools than currently available include: multiobjective criteria and nonconvex optimization. Efficient techniques to deal with optimization over combinatoric and continuous variables, and with truncation issues for structure and control parameters of both the model space as well as the design space need to be developed.

Comparison of glycemic control and variability in patients with type 2 and posttransplantation diabetes mellitus.

PubMed

Werzowa, Johannes; Pacini, Giovanni; Hecking, Manfred; Fidler, Catharina; Haidinger, Michael; Brath, Helmut; Thomas, Andreas; Säemann, Marcus D; Tura, Andrea

2015-01-01

Posttransplantation diabetes mellitus (PTDM) is a common complication after renal transplantation leading to increased cardiovascular morbidity and mortality. In subjects with type 2 diabetes (T2DM) increased glycemic variability and poor glycemic control have been associated with cardiovascular complications. We therefore aimed at determining glycemic variability and glycemic control in subjects with PTDM in comparison to T2DM subjects. In this observational study we analyzed 10 transplanted subjects without diabetes (Control), 10 transplanted subjects with PTDM, and 8 non-transplanted T2DM subjects using Continuous Glucose Monitoring (CGM). Several indices of glycemic control quality and variability were computed. Many indices of both glycemic control quality and variability were different between control and PTDM subjects, with worse values in PTDM. The indices of glycemic control, such as glucose mean, GRADE and M-value, were similar in PTDM and T2DM, but some indices of glycemic variability, that is CONGA, lability index and shape index, showed a markedly higher (i.e., worse) value in T2DM than in PTDM (P value range: 0.001-0.035). Although PTDM and T2DM subjects showed similar glycemic control quality, glycemic variability was significantly higher in T2DM. These data underscore potential important pathophysiological differences between T2DM and PTDM indicating that increased glycemic variability may not be a key factor for the excess cardiovascular mortality in patients with PTDM. Copyright © 2015 Elsevier Inc. All rights reserved.

Number versus Extent in Newborns' Spontaneous Preference for Collections of Dots

ERIC Educational Resources Information Center

Turati, Chiara; Gava, Lucia; Valenza, Eloisa; Ghirardi, Valentina

2013-01-01

This study investigated processing of number and extent in newborns. Using visual preference, we showed that newborns discriminated between small sets of dot collections relying solely on implicit numerical information when non-numerical continuous variables were strictly controlled (Experiment 1), and solely on continuous information when…

Using LDR as Sensing Element for an External Fuzzy Controller Applied in Photovoltaic Pumping Systems with Variable-Speed Drives.

PubMed

Maranhão, Geraldo Neves De A; Brito, Alaan Ubaiara; Leal, Anderson Marques; Fonseca, Jéssica Kelly Silva; Macêdo, Wilson Negrão

2015-09-22

In the present paper, a fuzzy controller applied to a Variable-Speed Drive (VSD) for use in Photovoltaic Pumping Systems (PVPS) is proposed. The fuzzy logic system (FLS) used is embedded in a microcontroller and corresponds to a proportional-derivative controller. A Light-Dependent Resistor (LDR) is used to measure, approximately, the irradiance incident on the PV array. Experimental tests are executed using an Arduino board. The experimental results show that the fuzzy controller is capable of operating the system continuously throughout the day and controlling the direct current (DC) voltage level in the VSD with a good performance.

Bayesian adjustment for measurement error in continuous exposures in an individually matched case-control study.

PubMed

Espino-Hernandez, Gabriela; Gustafson, Paul; Burstyn, Igor

2011-05-14

In epidemiological studies explanatory variables are frequently subject to measurement error. The aim of this paper is to develop a Bayesian method to correct for measurement error in multiple continuous exposures in individually matched case-control studies. This is a topic that has not been widely investigated. The new method is illustrated using data from an individually matched case-control study of the association between thyroid hormone levels during pregnancy and exposure to perfluorinated acids. The objective of the motivating study was to examine the risk of maternal hypothyroxinemia due to exposure to three perfluorinated acids measured on a continuous scale. Results from the proposed method are compared with those obtained from a naive analysis. Using a Bayesian approach, the developed method considers a classical measurement error model for the exposures, as well as the conditional logistic regression likelihood as the disease model, together with a random-effect exposure model. Proper and diffuse prior distributions are assigned, and results from a quality control experiment are used to estimate the perfluorinated acids' measurement error variability. As a result, posterior distributions and 95% credible intervals of the odds ratios are computed. A sensitivity analysis of method's performance in this particular application with different measurement error variability was performed. The proposed Bayesian method to correct for measurement error is feasible and can be implemented using statistical software. For the study on perfluorinated acids, a comparison of the inferences which are corrected for measurement error to those which ignore it indicates that little adjustment is manifested for the level of measurement error actually exhibited in the exposures. Nevertheless, a sensitivity analysis shows that more substantial adjustments arise if larger measurement errors are assumed. In individually matched case-control studies, the use of conditional logistic regression likelihood as a disease model in the presence of measurement error in multiple continuous exposures can be justified by having a random-effect exposure model. The proposed method can be successfully implemented in WinBUGS to correct individually matched case-control studies for several mismeasured continuous exposures under a classical measurement error model.

How do Durkheimian variables impact variation in national suicide rates when proxies for depression and alcoholism are controlled?

PubMed

Fernquist, Robert M

2007-01-01

Sociological research on Durkheim's theories of egoistic and anomic suicide has given Durkheim continued support more than a century after Durkheim published his work. Recent criticism by Breault (1994), though, argues that Durkheim's theories of suicide actually have not been empirically supported given the lack of psychological variables included in sociological research on suicide rates. Using proxy measures of depression and alcoholism, two known psychological variables to impact suicide, as well as classic Durkheimian variables, suicide rates in eight European countries from 1973-1997 were examined. Results indicate that Durkheim's theories of egoism and anomie, while not completely supported in statistical analysis of suicide rates, received moderate support. Results suggest the continued usefulness of Durkheim's work in aggregate analyses of suicide.

Measuring P-V-T Phase Behavior with a Variable Volume View Cell

ERIC Educational Resources Information Center

Hoffmann, Markus M.; Salter, Jason D.

2004-01-01

An experiment using a variable volume cell is presented where students actively control and directly observe the phase equilibrium inside the view cell. Measuring and exploring P-V-T phase behavior through dielectric constant measurements conveys the important concept that solvent behavior can be changed continuously in the sc fluid state.

Effect of Acarbose on Glycemic Variability in Patients with Poorly Controlled Type 2 Diabetes Mellitus Receiving Stable Background Therapy: A Placebo-Controlled Trial.

PubMed

Derosa, Giuseppe; Franzetti, Ivano; Querci, Fabrizio; D'Angelo, Angela; Maffioli, Pamela

2015-11-01

To evaluate the effect of acarbose on glycemic control and glycemic variability, using a continuous glucose-monitoring system, in patients with type 2 diabetes mellitus who were not well controlled on metformin and vildagliptin therapy. Multicenter, randomized, double-blind, placebo-controlled study. Clinical research units at three hospitals in Italy. Fifty-three patients with type 2 diabetes who were taking stable dosages of metformin 850 mg 3 times/day and vildagliptin 50 mg twice/day for at least 3 months and who were not adequately controlled with these therapies. Patients were randomized to either placebo or acarbose 100 mg 3 times/day to be added to their metformin-vildagliptin regimen. Glycemic excursions were assessed by using a continuous glucose-monitoring system for 1 week. Glycemic control was estimated as the mean blood glucose (MBG) level, the area under the glucose concentration-time curve for a glucose level above 70 mg/dl (AUC above 70) or 180 mg/dl (AUC above 180), and the percentage of time that the glucose level was above 70 mg/dl (T above 70) or 180 mg/dl (T above 180). Intraday glycemic variability was assessed by the standard deviation of the blood glucose level, the mean amplitude of glycemic excursions (MAGE), the M value, and continuous overlapping net glycemic action. Day-to-day glycemic variability was assessed as the mean of daily difference (MODD). The MBG level was ~20 mg/dl lower in the acarbose group than in the placebo group (p<0.05), particularly during the postprandial period. The AUC above 70 did not significantly differ between the two groups, whereas the AUC above 180 was ~40% lower in the acarbose group than in the placebo group during the daytime (p<0.01). The T above 180 was significantly higher in the placebo group than in the acarbose group (31% vs 8%, p<0.01. Moreover, the standard deviation and MAGE values were significantly lower in the acarbose group. The MODD value was not significantly changed in either group, and no significant differences were recorded between groups. All adverse events were mild in both groups, with only a significantly greater frequency of flatulence noted in the acarbose group (5% with acarbose vs 0.5% with placebo, p<0.05). The addition of acarbose to metformin and vildagliptin background therapy in patients with inadequately controlled type 2 diabetes decreased intraday glycemic variability, especially postprandial variability, but it was not associated with a significant change in interday glycemic variability. © 2015 Pharmacotherapy Publications, Inc.

Analysis on flood generation processes by means of a continuous simulation model

NASA Astrophysics Data System (ADS)

Fiorentino, M.; Gioia, A.; Iacobellis, V.; Manfreda, S.

2006-03-01

In the present research, we exploited a continuous hydrological simulation to investigate on key variables responsible of flood peak formation. With this purpose, a distributed hydrological model (DREAM) is used in cascade with a rainfall generator (IRP-Iterated Random Pulse) to simulate a large number of extreme events providing insight into the main controls of flood generation mechanisms. Investigated variables are those used in theoretically derived probability distribution of floods based on the concept of partial contributing area (e.g. Iacobellis and Fiorentino, 2000). The continuous simulation model is used to investigate on the hydrological losses occurring during extreme events, the variability of the source area contributing to the flood peak and its lag-time. Results suggest interesting simplification for the theoretical probability distribution of floods according to the different climatic and geomorfologic environments. The study is applied to two basins located in Southern Italy with different climatic characteristics.

QKD Via a Quantum Wavelength Router Using Spatial Soliton

NASA Astrophysics Data System (ADS)

Kouhnavard, M.; Amiri, I. S.; Afroozeh, A.; Jalil, M. A.; Ali, J.; Yupapin, P. P.

2011-05-01

A system for continuous variable quantum key distribution via a wavelength router is proposed. The Kerr type of light in the nonlinear microring resonator (NMRR) induces the chaotic behavior. In this proposed system chaotic signals are generated by an optical soliton or Gaussian pulse within a NMRR system. The parameters, such as input power, MRRs radii and coupling coefficients can change and plays important role in determining the results in which the continuous signals are generated spreading over the spectrum. Large bandwidth signals of optical soliton are generated by the input pulse propagating within the MRRs, which is allowed to form the continuous wavelength or frequency with large tunable channel capacity. The continuous variable QKD is formed by using the localized spatial soliton pulses via a quantum router and networks. The selected optical spatial pulse can be used to perform the secure communication network. Here the entangled photon generated by chaotic signals has been analyzed. The continuous entangled photon is generated by using the polarization control unit incorporating into the MRRs, required to provide the continuous variable QKD. Results obtained have shown that the application of such a system for the simultaneous continuous variable quantum cryptography can be used in the mobile telephone hand set and networks. In this study frequency band of 500 MHz and 2.0 GHz and wavelengths of 775 nm, 2,325 nm and 1.55 μm can be obtained for QKD use with input optical soliton and Gaussian beam respectively.

The effect of poverty-influenced, food-related consumer behaviors on obesity: An analysis of the NHANES flexible consumer behavioral module.

PubMed

O'Dare Wilson, Kellie

2017-01-01

Despite extensive research investigating obesity, the problem continues to increase, particularly in poor, minority, and under-resourced communities. However, the literature continues to demonstrate many obesity-predicating variables are outside of personal volitional control, such as food-related consumer behaviors, which are strongly influenced by income and environment. This cross-sectional study (n = 5,109) employed secondary data analysis to quantitatively examine the effect of food-related consumer variables on obesity while controlling for covariates. Participants answered questions regarding money spent on food, time preparing meals, number of meals eaten at home and away from home, and types of food products consumed (frozen/fast foods, sodas, salty snacks, etc.) In this study, 48.9% of respondents were either overweight or obese. No significant differences were noted between the contextual variables examined and BMI scores. However, given the sample's limitations illuminated in the study, further research regarding the relationship between obesity and poverty-influenced, food-related consumer behaviors is warranted.

Using LDR as Sensing Element for an External Fuzzy Controller Applied in Photovoltaic Pumping Systems with Variable-Speed Drives

PubMed Central

Maranhão, Geraldo Neves De A.; Brito, Alaan Ubaiara; Leal, Anderson Marques; Fonseca, Jéssica Kelly Silva; Macêdo, Wilson Negrão

2015-01-01

In the present paper, a fuzzy controller applied to a Variable-Speed Drive (VSD) for use in Photovoltaic Pumping Systems (PVPS) is proposed. The fuzzy logic system (FLS) used is embedded in a microcontroller and corresponds to a proportional-derivative controller. A Light-Dependent Resistor (LDR) is used to measure, approximately, the irradiance incident on the PV array. Experimental tests are executed using an Arduino board. The experimental results show that the fuzzy controller is capable of operating the system continuously throughout the day and controlling the direct current (DC) voltage level in the VSD with a good performance. PMID:26402688

Wave-variable framework for networked robotic systems with time delays and packet losses

NASA Astrophysics Data System (ADS)

Puah, Seng-Ming; Liu, Yen-Chen

2017-05-01

This paper investigates the problem of networked control system for nonlinear robotic manipulators under time delays and packet loss by using passivity technique. With the utilisation of wave variables and a passive remote controller, the networked robotic system is demonstrated to be stable with guaranteed position regulation. For the input/output signals of robotic systems, a discretisation block is exploited to convert continuous-time signals to discrete-time signals, and vice versa. Subsequently, we propose a packet management, called wave-variable modulation, to cope with the proposed networked robotic system under time delays and packet losses. Numerical examples and experimental results are presented to demonstrate the performance of the proposed wave-variable-based networked robotic systems.

Modeling and control of operator functional state in a unified framework of fuzzy inference petri nets.

PubMed

Zhang, Jian-Hua; Xia, Jia-Jun; Garibaldi, Jonathan M; Groumpos, Petros P; Wang, Ru-Bin

2017-06-01

In human-machine (HM) hybrid control systems, human operator and machine cooperate to achieve the control objectives. To enhance the overall HM system performance, the discrete manual control task-load by the operator must be dynamically allocated in accordance with continuous-time fluctuation of psychophysiological functional status of the operator, so-called operator functional state (OFS). The behavior of the HM system is hybrid in nature due to the co-existence of discrete task-load (control) variable and continuous operator performance (system output) variable. Petri net is an effective tool for modeling discrete event systems, but for hybrid system involving discrete dynamics, generally Petri net model has to be extended. Instead of using different tools to represent continuous and discrete components of a hybrid system, this paper proposed a method of fuzzy inference Petri nets (FIPN) to represent the HM hybrid system comprising a Mamdani-type fuzzy model of OFS and a logical switching controller in a unified framework, in which the task-load level is dynamically reallocated between the operator and machine based on the model-predicted OFS. Furthermore, this paper used a multi-model approach to predict the operator performance based on three electroencephalographic (EEG) input variables (features) via the Wang-Mendel (WM) fuzzy modeling method. The membership function parameters of fuzzy OFS model for each experimental participant were optimized using artificial bee colony (ABC) evolutionary algorithm. Three performance indices, RMSE, MRE, and EPR, were computed to evaluate the overall modeling accuracy. Experiment data from six participants are analyzed. The results show that the proposed method (FIPN with adaptive task allocation) yields lower breakdown rate (from 14.8% to 3.27%) and higher human performance (from 90.30% to 91.99%). The simulation results of the FIPN-based adaptive HM (AHM) system on six experimental participants demonstrate that the FIPN framework provides an effective way to model and regulate/optimize the OFS in HM hybrid systems composed of continuous-time OFS model and discrete-event switching controller. Copyright © 2017 Elsevier B.V. All rights reserved.

Fundamental Principles of Coherent-Feedback Quantum Control

DTIC Science & Technology

2014-12-08

in metrology (acceleration sensing, vibrometry, gravity wave detection) and in quantum information processing (continuous-variables quantum ...AFRL-OSR-VA-TR-2015-0009 FUNDAMENTAL PRINCIPLES OF COHERENT-FEEDBACK QUANTUM CONTROL Hideo Mabuchi LELAND STANFORD JUNIOR UNIV CA Final Report 12/08...foundations and potential applications of coherent-feedback quantum control. We have focused on potential applications in quantum -enhanced metrology and

How to decompose arbitrary continuous-variable quantum operations.

PubMed

Sefi, Seckin; van Loock, Peter

2011-10-21

We present a general, systematic, and efficient method for decomposing any given exponential operator of bosonic mode operators, describing an arbitrary multimode Hamiltonian evolution, into a set of universal unitary gates. Although our approach is mainly oriented towards continuous-variable quantum computation, it may be used more generally whenever quantum states are to be transformed deterministically, e.g., in quantum control, discrete-variable quantum computation, or Hamiltonian simulation. We illustrate our scheme by presenting decompositions for various nonlinear Hamiltonians including quartic Kerr interactions. Finally, we conclude with two potential experiments utilizing offline-prepared optical cubic states and homodyne detections, in which quantum information is processed optically or in an atomic memory using quadratic light-atom interactions. © 2011 American Physical Society

System-wide hybrid MPC-PID control of a continuous pharmaceutical tablet manufacturing process via direct compaction.

PubMed

Singh, Ravendra; Ierapetritou, Marianthi; Ramachandran, Rohit

2013-11-01

The next generation of QbD based pharmaceutical products will be manufactured through continuous processing. This will allow the integration of online/inline monitoring tools, coupled with an efficient advanced model-based feedback control systems, to achieve precise control of process variables, so that the predefined product quality can be achieved consistently. The direct compaction process considered in this study is highly interactive and involves time delays for a number of process variables due to sensor placements, process equipment dimensions, and the flow characteristics of the solid material. A simple feedback regulatory control system (e.g., PI(D)) by itself may not be sufficient to achieve the tight process control that is mandated by regulatory authorities. The process presented herein comprises of coupled dynamics involving slow and fast responses, indicating the requirement of a hybrid control scheme such as a combined MPC-PID control scheme. In this manuscript, an efficient system-wide hybrid control strategy for an integrated continuous pharmaceutical tablet manufacturing process via direct compaction has been designed. The designed control system is a hybrid scheme of MPC-PID control. An effective controller parameter tuning strategy involving an ITAE method coupled with an optimization strategy has been used for tuning of both MPC and PID parameters. The designed hybrid control system has been implemented in a first-principles model-based flowsheet that was simulated in gPROMS (Process System Enterprise). Results demonstrate enhanced performance of critical quality attributes (CQAs) under the hybrid control scheme compared to only PID or MPC control schemes, illustrating the potential of a hybrid control scheme in improving pharmaceutical manufacturing operations. Copyright © 2013 Elsevier B.V. All rights reserved.

Dream controller

DOEpatents

Cheng, George Shu-Xing; Mulkey, Steven L; Wang, Qiang; Chow, Andrew J

2013-11-26

A method and apparatus for intelligently controlling continuous process variables. A Dream Controller comprises an Intelligent Engine mechanism and a number of Model-Free Adaptive (MFA) controllers, each of which is suitable to control a process with specific behaviors. The Intelligent Engine can automatically select the appropriate MFA controller and its parameters so that the Dream Controller can be easily used by people with limited control experience and those who do not have the time to commission, tune, and maintain automatic controllers.

Experimental implementation of non-Gaussian attacks on a continuous-variable quantum-key-distribution system.

PubMed

Lodewyck, Jérôme; Debuisschert, Thierry; García-Patrón, Raúl; Tualle-Brouri, Rosa; Cerf, Nicolas J; Grangier, Philippe

2007-01-19

An intercept-resend attack on a continuous-variable quantum-key-distribution protocol is investigated experimentally. By varying the interception fraction, one can implement a family of attacks where the eavesdropper totally controls the channel parameters. In general, such attacks add excess noise in the channel, and may also result in non-Gaussian output distributions. We implement and characterize the measurements needed to detect these attacks, and evaluate experimentally the information rates available to the legitimate users and the eavesdropper. The results are consistent with the optimality of Gaussian attacks resulting from the security proofs.

A Maximum Likelihood Approach for Multisample Nonlinear Structural Equation Models with Missing Continuous and Dichotomous Data

ERIC Educational Resources Information Center

Song, Xin-Yuan; Lee, Sik-Yum

2006-01-01

Structural equation models are widely appreciated in social-psychological research and other behavioral research to model relations between latent constructs and manifest variables and to control for measurement error. Most applications of SEMs are based on fully observed continuous normal data and models with a linear structural equation.…

Application of loop analysis for evaluation of malaria control interventions.

PubMed

Yasuoka, Junko; Jimba, Masamine; Levins, Richard

2014-04-09

Despite continuous efforts and recent rapid expansion in the financing and implementation of malaria control interventions, malaria still remains one of the most devastating global health issues. Even in countries that have been successful in reducing the incidence of malaria, malaria control is becoming more challenging because of the changing epidemiology of malaria and waning community participation in control interventions. In order to improve the effectiveness of interventions and to promote community understanding of the necessity of continued control efforts, there is an urgent need to develop new methodologies that examine the mechanisms by which community-based malaria interventions could reduce local malaria incidence. This study demonstrated how the impact of community-based malaria control interventions on malaria incidence can be examined in complex systems by qualitative analysis combined with an extensive review of literature. First, sign digraphs were developed through loop analysis to analyse seven interventions: source reduction, insecticide/larvicide use, biological control, treatment with anti-malarials, insecticide-treated mosquito net/long-lasting insecticidal net, non-chemical personal protection measures, and educational intervention. Then, for each intervention, the sign digraphs and literature review were combined to analyse a variety of pathways through which the intervention can influence local malaria incidence as well as interactions between variables involved in the system. Through loop analysis it is possible to see whether increases in one variable qualitatively increases or decreases other variables or leaves them unchanged and the net effect of multiple, interacting variables. Qualitative analysis, specifically loop analysis, can be a useful tool to examine the impact of community-based malaria control interventions. Without relying on numerical data, the analysis was able to describe pathways through which each intervention could influence malaria incidence on the basis of the qualitative patterns of the interactions between variables in complex systems. This methodology is generalizable to various disease control interventions at different levels, and can be utilized by a variety of stakeholders such as researchers, community leaders and policy makers to better plan and evaluate their community-based disease control interventions.

Application of loop analysis for evaluation of malaria control interventions

PubMed Central

2014-01-01

Background Despite continuous efforts and recent rapid expansion in the financing and implementation of malaria control interventions, malaria still remains one of the most devastating global health issues. Even in countries that have been successful in reducing the incidence of malaria, malaria control is becoming more challenging because of the changing epidemiology of malaria and waning community participation in control interventions. In order to improve the effectiveness of interventions and to promote community understanding of the necessity of continued control efforts, there is an urgent need to develop new methodologies that examine the mechanisms by which community-based malaria interventions could reduce local malaria incidence. Methods This study demonstrated how the impact of community-based malaria control interventions on malaria incidence can be examined in complex systems by qualitative analysis combined with an extensive review of literature. First, sign digraphs were developed through loop analysis to analyse seven interventions: source reduction, insecticide/larvicide use, biological control, treatment with anti-malarials, insecticide-treated mosquito net/long-lasting insecticidal net, non-chemical personal protection measures, and educational intervention. Then, for each intervention, the sign digraphs and literature review were combined to analyse a variety of pathways through which the intervention can influence local malaria incidence as well as interactions between variables involved in the system. Through loop analysis it is possible to see whether increases in one variable qualitatively increases or decreases other variables or leaves them unchanged and the net effect of multiple, interacting variables. Results Qualitative analysis, specifically loop analysis, can be a useful tool to examine the impact of community-based malaria control interventions. Without relying on numerical data, the analysis was able to describe pathways through which each intervention could influence malaria incidence on the basis of the qualitative patterns of the interactions between variables in complex systems. This methodology is generalizable to various disease control interventions at different levels, and can be utilized by a variety of stakeholders such as researchers, community leaders and policy makers to better plan and evaluate their community-based disease control interventions. PMID:24713031

A discrete decentralized variable structure robotic controller

NASA Technical Reports Server (NTRS)

Tumeh, Zuheir S.

1989-01-01

A decentralized trajectory controller for robotic manipulators is designed and tested using a multiprocessor architecture and a PUMA 560 robot arm. The controller is made up of a nominal model-based component and a correction component based on a variable structure suction control approach. The second control component is designed using bounds on the difference between the used and actual values of the model parameters. Since the continuous manipulator system is digitally controlled along a trajectory, a discretized equivalent model of the manipulator is used to derive the controller. The motivation for decentralized control is that the derived algorithms can be executed in parallel using a distributed, relatively inexpensive, architecture where each joint is assigned a microprocessor. Nonlinear interaction and coupling between joints is treated as a disturbance torque that is estimated and compensated for.

Continuous Venovenous Hemofiltration in Severely Burned Patients with Acute Kidney Injury: A Cohort Study

DTIC Science & Technology

2009-05-01

to result in any extra- renal effects. In the CVVH group the initial prescribed dose was variable based on hemo- dynamic compromise and perceived...associated with a decrease in 28-day and hospital mortality when compared with a historical control group, which largely did not receive any form of renal ...BUN: blood urea nitrogen; CVVH: continuous venovenous hemofiltration; CVVHDF: continuous venovenous hemodiafiltration; ESRD: end-stage renal disease

Variable-Speed Simulation of a Dual-Clutch Gearbox Tiltrotor Driveline

NASA Technical Reports Server (NTRS)

DeSmidt, Hans; Wang, Kon-Well; Smith, Edward C.; Lewicki, David G.

2012-01-01

This investigation explores the variable-speed operation and shift response of a prototypical two-speed dual-clutch transmission tiltrotor driveline in forward flight. Here, a Comprehensive Variable-Speed Rotorcraft Propulsion System Modeling (CVSRPM) tool developed under a NASA funded NRA program is utilized to simulate the drive system dynamics. In this study, a sequential shifting control strategy is analyzed under a steady forward cruise condition. This investigation attempts to build upon previous variable-speed rotorcraft propulsion studies by 1) including a fully nonlinear transient gas-turbine engine model, 2) including clutch stick-slip friction effects, 3) including shaft flexibility, 4) incorporating a basic flight dynamics model to account for interactions with the flight control system. Through exploring the interactions between the various subsystems, this analysis provides important insights into the continuing development of variable-speed rotorcraft propulsion systems.

Variable Structure PID Control to Prevent Integrator Windup

NASA Technical Reports Server (NTRS)

Hall, C. E.; Hodel, A. S.; Hung, J. Y.

1999-01-01

PID controllers are frequently used to control systems requiring zero steady-state error while maintaining requirements for settling time and robustness (gain/phase margins). PID controllers suffer significant loss of performance due to short-term integrator wind-up when used in systems with actuator saturation. We examine several existing and proposed methods for the prevention of integrator wind-up in both continuous and discrete time implementations.

Prospective versus predictive control in timing of hitting a falling ball.

PubMed

Katsumata, Hiromu; Russell, Daniel M

2012-02-01

Debate exists as to whether humans use prospective or predictive control to intercept an object falling under gravity (Baurès et al. in Vis Res 47:2982-2991, 2007; Zago et al. in Vis Res 48:1532-1538, 2008). Prospective control involves using continuous information to regulate action. τ, the ratio of the size of the gap to the rate of gap closure, has been proposed as the information used in guiding interceptive actions prospectively (Lee in Ecol Psychol 10:221-250, 1998). This form of control is expected to generate movement modulation, where variability decreases over the course of an action based upon more accurate timing information. In contrast, predictive control assumes that a pre-programmed movement is triggered at an appropriate criterion timing variable. For a falling object it is commonly argued that an internal model of gravitational acceleration is used to predict the motion of the object and determine movement initiation. This form of control predicts fixed duration movements initiated at consistent time-to-contact (TTC), either across conditions (constant criterion operational timing) or within conditions (variable criterion operational timing). The current study sought to test predictive and prospective control hypotheses by disrupting continuous visual information of a falling ball and examining consistency in movement initiation and duration, and evidence for movement modulation. Participants (n = 12) batted a ball dropped from three different heights (1, 1.3 and 1.5 m), under both full-vision and partial occlusion conditions. In the occlusion condition, only the initial ball drop and the final 200 ms of ball flight to the interception point could be observed. The initiation of the swing did not occur at a consistent TTC, τ, or any other timing variable across drop heights, in contrast with previous research. However, movement onset was not impacted by occluding the ball flight for 280-380 ms. This finding indicates that humans did not need to be continuously coupled to vision of the ball to initiate the swing accurately, but instead could use predictive control based on acceleration timing information (TTC2). However, other results provide evidence for movement modulation, a characteristic of prospective control. Strong correlations between movement initiation and duration and reduced timing variability from swing onset to arrival at the interception point, both support compensatory variability. An analysis of modulation within the swing revealed that early in the swing, the movement acceleration was strongly correlated to the required mean velocity at swing onset and that later in the swing, the movement acceleration was again strongly correlated with the current required mean velocity. Rather than a consistent movement initiated at the same time, these findings show that the swing was variable but modulated for meeting the demands of each trial. A prospective model of coupling τ (bat-ball) with τ (ball-target) was found to provide a very strong linear fit for an average of 69% of the movement duration. These findings provide evidence for predictive control based on TTC2 information in initiating the swing and prospective control based on τ in guiding the bat to intercept the ball.

[Automatic system control and its application in dialysis].

PubMed

Santoro, A; Mancini, E; Ferramosca, E

2007-01-01

The progressive increase in the mean age of dialysis patients associated with increasing comorbidity factors such as the presence of cardiovascular disease and diabetes have significantly worsened patients' clinical status and tolerance to hemodialysis. On the other hand, the demand for short treatment times increases the risk of hemodynamic instability as well as inadequate depuration. The traditional management of the dialysis session by setting predefined treatment parameters and carrying out active therapeutic intervention only in the event of complications is definitely unsuitable for short-lasting treatments, which are often complicated by hemodynamic instability, especially in critically ill patients. The first step in improving the management of the dialysis session is the use of uninvasive systems for continuous monitoring of the hemodynamic and biochemical parameters that characterize dialysis quality. In the last decade, special sensors have been designed for continuous measurement of blood volume, blood temperature, blood pressure, heart rate and electrolytes. As a second step, some of these devices have been interfaced with the dialysis equipment, mainly with a view to preventing cardiocirculatory instability but also monitoring the efficiency of dialysis (biofeedback control systems). The basic components of a biofeedback system are the plant, the sensors, the actuators, and the controller. The plant is the biological process we need to control, while the sensors are the devices used for measuring the output variables. The actuators are the working arms of the controller. The controller is the mathematical model that continuously sets the measured output variable against the reference input and modifies the actuators in order to reduce any discrepancies. In actual practice, however, there are a number of conceptual, physical and technological difficulties to overcome. In particular, the behavior of what is to be controlled may be nonlinear and time-varying, with interactions between the actuators and the controlled variable. In such cases, more sophisticated control systems are needed that must be capable of identifying the behavior of the process and continuously update information data while the control is on. These complex systems are called adaptive controllers. At present, there are three biofeedback systems routinely used in clinical dialysis. All of them are aimed at improving the cardiovascular stability during hemodialysis, which at present is one of the main problems limiting the tolerance to treatment on the one hand and the quality of hemodialysis on the other. These systems include biofeedback control of blood volume, biofeedback control of thermal balance, and biofeedback control of blood pressure.

Biofeedback-driven dialysis: where are we?

PubMed

Santoro, Antonio; Ferramosca, Emiliana; Mancini, Elena

2008-01-01

The progressive increase in the mean age and the growing conditions of co-morbidity, especially of cardiovascular pathologies and diabetes, have significantly worsened the patients' clinical status and tolerance to the hemodialysis (HD) treatment. On the other hand, the demand for short treatment times enhances the risk for hemodynamic instability as well as for inadequate depuration. The traditional management of the dialysis session, setting of predefined treatment parameters, with active therapeutic interventions only in the event of complications, is definitely unsuitable for short-lasting treatments, often complicated by hemodynamic instability, especially in critical patients. The first step to improve the management of the dialysis session is the utilization of continuous and uninvasive monitoring systems for hemodynamic or biochemical parameters involved in the dialysis quality. Special sensors for the continuous measurement of blood volume, blood temperature, blood pressure, heart rate, electrolytes, have been realized throughout the last 10 years. As a second step, some of these devices have been implemented in the dialysis instrumentation, mainly with a view to preventing cardiocirculatory instability but also to control the dialysis efficiency (biofeedback control systems). The basic components of a biofeedback system are: the plant, the sensors, the actuators and the controller. The plant is the biological process that we need to control, while the sensors are the devices used for measuring the output variables. The actuators are the working arms of the controller. The controller is the mathematical model that continuously sets the measured output variable against the reference input and modifies the actuators in order to reduce any discrepancies. Yet, in practice there are a number of conceptual, physical and technological difficulties to be overcome. In particular, the behavior of what is to be controlled may be non-linear and time-varying, with interactions between the actuators and the controlled variable. In these cases, more sophisticated control systems are needed, which must be capable of identifying the behavior of the process, and continuously update information data while the control is on. These complex systems are called adaptive controllers. In dialysis, over the last few years, it has been relatively easy to realize some biofeedback systems since a series of sensors have been developed for online monitoring. Three biofeedback devices are routinely used with the aim of improving the cardiovascular instability, one of the main problems limiting the tolerance to treatment by the patient and the quality of HD in itself - the first is the biofeedback control of blood volume, the second is the biofeedback control of thermal balance, and the third is the biofeedback control of blood pressure.

Online kinematic regulation by visual feedback for grasp versus transport during reach-to-pinch

PubMed Central

Nataraj, Raviraj; Pasluosta, Cristian; Li, Zong-Ming

2014-01-01

Purpose This study investigated novel kinematic performance parameters to understand regulation by visual feedback (VF) of the reaching hand on the grasp and transport components during the reach-to-pinch maneuver. Conventional metrics often signify discrete movement features to postulate sensory-based control effects (e.g., time for maximum velocity to signify feedback delay). The presented metrics of this study were devised to characterize relative vision-based control of the sub-movements across the entire maneuver. Methods Movement performance was assessed according to reduced variability and increased efficiency of kinematic trajectories. Variability was calculated as the standard deviation about the observed mean trajectory for a given subject and VF condition across kinematic derivatives for sub-movements of inter-pad grasp (distance between thumb and index finger-pads; relative orientation of finger-pads) and transport (distance traversed by wrist). A Markov analysis then examined the probabilistic effect of VF on which movement component exhibited higher variability over phases of the complete maneuver. Jerk-based metrics of smoothness (minimal jerk) and energy (integrated jerk-squared) were applied to indicate total movement efficiency with VF. Results/Discussion The reductions in grasp variability metrics with VF were significantly greater (p<0.05) compared to transport for velocity, acceleration, and jerk, suggesting separate control pathways for each component. The Markov analysis indicated that VF preferentially regulates grasp over transport when continuous control is modeled probabilistically during the movement. Efficiency measures demonstrated VF to be more integral for early motor planning of grasp than transport in producing greater increases in smoothness and trajectory adjustments (i.e., jerk-energy) early compared to late in the movement cycle. Conclusions These findings demonstrate the greater regulation by VF on kinematic performance of grasp compared to transport and how particular features of this relativistic control occur continually over the maneuver. Utilizing the advanced performance metrics presented in this study facilitated characterization of VF effects continuously across the entire movement in corroborating the notion of separate control pathways for each component. PMID:24968371

Vascular Glucose Sensor Symposium: Continuous Glucose Monitoring Systems (CGMS) for Hospitalized and Ambulatory Patients at Risk for Hyperglycemia, Hypoglycemia, and Glycemic Variability.

PubMed

Joseph, Jeffrey I; Torjman, Marc C; Strasma, Paul J

2015-07-01

Hyperglycemia, hypoglycemia, and glycemic variability have been associated with increased morbidity, mortality, length of stay, and cost in a variety of critical care and non-critical care patient populations in the hospital. The results from prospective randomized clinical trials designed to determine the risks and benefits of intensive insulin therapy and tight glycemic control have been confusing; and at times conflicting. The limitations of point-of-care blood glucose (BG) monitoring in the hospital highlight the great clinical need for an automated real-time continuous glucose monitoring system (CGMS) that can accurately measure the concentration of glucose every few minutes. Automation and standardization of the glucose measurement process have the potential to significantly improve BG control, clinical outcome, safety and cost. © 2015 Diabetes Technology Society.

The symbol-grounding problem in numerical cognition: A review of theory, evidence, and outstanding questions.

PubMed

Leibovich, Tali; Ansari, Daniel

2016-03-01

How do numerical symbols, such as number words, acquire semantic meaning? This question, also referred to as the "symbol-grounding problem," is a central problem in the field of numerical cognition. Present theories suggest that symbols acquire their meaning by being mapped onto an approximate system for the nonsymbolic representation of number (Approximate Number System or ANS). In the present literature review, we first asked to which extent current behavioural and neuroimaging data support this theory, and second, to which extent the ANS, upon which symbolic numbers are assumed to be grounded, is numerical in nature. We conclude that (a) current evidence that has examined the association between the ANS and number symbols does not support the notion that number symbols are grounded in the ANS and (b) given the strong correlation between numerosity and continuous variables in nonsymbolic number processing tasks, it is next to impossible to measure the pure association between symbolic and nonsymbolic numerosity. Instead, it is clear that significant cognitive control resources are required to disambiguate numerical from continuous variables during nonsymbolic number processing. Thus, if there exists any mapping between the ANS and symbolic number, then this process of association must be mediated by cognitive control. Taken together, we suggest that studying the role of both cognitive control and continuous variables in numerosity comparison tasks will provide a more complete picture of the symbol-grounding problem. (c) 2016 APA, all rights reserved).

"What Controls the Structure and Stability of the Ocean Meridional Overturning Circulation: Implications for Abrupt Climate Change?"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fedorov, Alexey

2013-11-23

The central goal of this research project is to understand the properties of the ocean meridional overturning circulation (MOC) – a topic critical for understanding climate variability and stability on a variety of timescales (from decadal to centennial and longer). Specifically, we have explored various factors that control the MOC stability and decadal variability in the Atlantic and the ocean thermal structure in general, including the possibility abrupt climate change. We have also continued efforts on improving the performance of coupled ocean-atmosphere GCMs.

Patient characteristics and variability in adherence and competence in cognitive-behavioral therapy for panic disorder.

PubMed

Boswell, James F; Gallagher, Matthew W; Sauer-Zavala, Shannon E; Bullis, Jacqueline; Gorman, Jack M; Shear, M Katherine; Woods, Scott; Barlow, David H

2013-06-01

Although associations with outcome have been inconsistent, therapist adherence and competence continues to garner attention, particularly within the context of increasing interest in the dissemination, implementation, and sustainability of evidence-based treatments. To date, research on therapist adherence and competence has focused on average levels across therapists. With a few exceptions, research has failed to address multiple sources of variability in adherence and competence, identify important factors that might account for variability, or take these sources of variability into account when examining associations with symptom change. (a) statistically demonstrate between- and within-therapist variability in adherence and competence ratings and examine patient characteristics as predictors of this variability and (b) examine the relationship between adherence/competence and symptom change. Randomly selected audiotaped sessions from a randomized controlled trial of cognitive-behavioral therapy for panic disorder were rated for therapist adherence and competence. Patients completed a self-report measure of panic symptom severity prior to each session and the Inventory of Interpersonal Problems-Personality Disorder Scale prior to the start of treatment. Significant between- and within-therapist variability in adherence and competence were observed. Adherence and competence deteriorated significantly over the course of treatment. Higher patient interpersonal aggression was associated with decrements in both adherence and competence. Neither adherence nor competence predicted subsequent panic severity. Variability and "drift" in adherence and competence can be observed in controlled trials. Training and implementation efforts should involve continued consultation over multiple cases in order to account for relevant patient factors and promote sustainability across sessions and patients.

Continuous Wheel Momentum Dumping Using Magnetic Torquers and Thrusters

NASA Astrophysics Data System (ADS)

Oh, Hwa-Suk; Choi, Wan-Sik; Eun, Jong-Won

1996-12-01

Two momentum management schemes using magnetic torquers and thrusters are sug-gested. The stability of the momentum dumping logic is proved at a general attitude equilibrium. Both momentum dumping control laws are implemented with Pulse-Width- Pulse-Frequency Modulated on-off control, and shown working equally well with the original continuous and variable strength control law. Thrusters are assummed to be asymmetrically configured as a contingency case. Each thruster is fired following separated control laws rather than paired thrusting. Null torque thrusting control is added on the thrust control calculated from the momentum control law for the gener-ation of positive thrusting force. Both magnetic and thrusting control laws guarantee the momentum dumping, however, the wheel inner loop control is needed for the "wheel speed" dumping, The control laws are simulated on the KOrea Multi-Purpose SATellite (KOMPSAT) model.

Robust integral variable structure controller and pulse-width pulse-frequency modulated input shaper design for flexible spacecraft with mismatched uncertainty/disturbance.

PubMed

Hu, Qinglei

2007-10-01

This paper presents a dual-stage control system design method for the flexible spacecraft attitude maneuvering control by use of on-off thrusters and active vibration control by input shaper. In this design approach, attitude control system and vibration suppression were designed separately using lower order model. As a stepping stone, an integral variable structure controller with the assumption of knowing the upper bounds of the mismatched lumped perturbation has been designed which ensures exponential convergence of attitude angle and angular velocity in the presence of bounded uncertainty/disturbances. To reconstruct estimates of the system states for use in a full information variable structure control law, an asymptotic variable structure observer is also employed. In addition, the thruster output is modulated in pulse-width pulse-frequency so that the output profile is similar to the continuous control histories. For actively suppressing the induced vibration, the input shaping technique is used to modify the existing command so that less vibration will be caused by the command itself, which only requires information about the vibration frequency and damping of the closed-loop system. The rationale behind this hybrid control scheme is that the integral variable structure controller can achieve good precision pointing, even in the presence of uncertainties/disturbances, whereas the shaped input attenuator is applied to actively suppress the undesirable vibrations excited by the rapid maneuvers. Simulation results for the spacecraft model show precise attitude control and vibration suppression.

Continuous relative phase variability during an exhaustive run in runners with a history of iliotibial band syndrome.

PubMed

Miller, Ross H; Meardon, Stacey A; Derrick, Timothy R; Gillette, Jason C

2008-08-01

Previous research has proposed that a lack of variability in lower extremity coupling during running is associated with pathology. The purpose of the study was to evaluate lower extremity coupling variability in runners with and without a history of iliotibial band syndrome (ITBS) during an exhaustive run. Sixteen runners ran to voluntary exhaustion on a motorized treadmill while a motion capture system recorded reflective marker locations. Eight runners had a history of ITBS. At the start and end of the run, continuous relative phase (CRP) angles and CRP variability between strides were calculated for key lower extremity kinematic couplings. The ITBS runners demonstrated less CRP variability than controls in several couplings between segments that have been associated with knee pain and ITBS symptoms, including tibia rotation-rearfoot motion and rearfoot motion-thigh ad/abduction, but more variability in knee flexion/extension-foot ad/abduction. The ITBS runners also demonstrated low variability at heel strike in coupling between rearfoot motion-tibia rotation. The results suggest that runners prone to ITBS use abnormal segmental coordination patterns, particular in couplings involving thigh ad/abduction and tibia internal/external rotation. Implications for variability in injury etiology are suggested.

Momentum management strategy during Space Station buildup

NASA Technical Reports Server (NTRS)

Bishop, Lynda; Malchow, Harvey; Hattis, Philip

1988-01-01

The use of momentum storage devices to control effectors for Space Station attitude control throughout the buildup sequence is discussed. Particular attention is given to the problem of providing satisfactory management of momentum storage effectors throughout buildup while experiencing variable torque loading. Continuous and discrete control strategies are compared and the effects of alternative control moment gyro strategies on peak momentum storage requirements and on commanded maneuver characteristics are described.

Further Results on Finite-Time Partial Stability and Stabilization. Applications to Nonlinear Control Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jammazi, Chaker

2009-03-05

The paper gives Lyapunov type sufficient conditions for partial finite-time and asymptotic stability in which some state variables converge to zero while the rest converge to constant values that possibly depend on the initial conditions. The paper then presents partially asymptotically stabilizing controllers for many nonlinear control systems for which continuous asymptotically stabilizing (in the usual sense) controllers are known not to exist.

Continuous light after a long-day treatment is equivalent to melatonin implants to stimulate testosterone secretion in Alpine male goats.

PubMed

Delgadillo, J A; Vélez, L I; Flores, J A

2016-04-01

In rams, artificial long days followed by continuous light stimulate testosterone secretion during the non-breeding season. The objective of this study was to determine whether artificial long days followed by continuous light could stimulate testosterone secretion in Alpine bucks as well as in those exposed to long days followed by a melatonin treatment. All bucks were kept in shaded open pens. Control males were exposed to natural photoperiod conditions (n=5). Males of the two experimental groups were exposed to 2.5 months of long days from 1 December (n=5 each). On 16 February, one group of males was exposed to 24 h of light per day until 30 June; the other group was exposed to natural variations of photoperiod and received two s.c. melatonin implants. Testicular weight was determined every 2 weeks, and the plasma testosterone concentrations once a week. In the control and the two photoperiodic-treated groups, a treatment×time interaction was detected for testicular weight and plasma testosterone concentrations (P<0.001). In control bucks, testicular weight increased from January and peaked in June, whereas in both photoperiodic-treated groups, this variable increased from January, but peaked in April, when the values were higher than in controls (P<0.05). In the control group, plasma testosterone concentrations remained low from January to June, whereas in both photoperiodic-treated groups, this variable remained low from January to March; thereafter, these levels increased in both photoperiodic-treated groups, and were higher than controls in April and May (P<0.05). We conclude that continuous light after a long-day treatment stimulate testosterone secretion in Alpine male goats during the non-breeding season as well as the long days followed by a melatonin treatment. Therefore, continuous light could replace the implants of melatonin.

Periodicity and chaos from switched flow systems - Contrasting examples of discretely controlled continuous systems

NASA Technical Reports Server (NTRS)

Chase, Christopher; Serrano, Joseph; Ramadge, Peter J.

1993-01-01

We analyze two examples of the discrete control of a continuous variable system. These examples exhibit what may be regarded as the two extremes of complexity of the closed-loop behavior: one is eventually periodic, the other is chaotic. Our examples are derived from sampled deterministic flow models. These are of interest in their own right but have also been used as models for certain aspects of manufacturing systems. In each case, we give a precise characterization of the closed-loop behavior.

Discrete factor approximations in simultaneous equation models: estimating the impact of a dummy endogenous variable on a continuous outcome.

PubMed

Mroz, T A

1999-10-01

This paper contains a Monte Carlo evaluation of estimators used to control for endogeneity of dummy explanatory variables in continuous outcome regression models. When the true model has bivariate normal disturbances, estimators using discrete factor approximations compare favorably to efficient estimators in terms of precision and bias; these approximation estimators dominate all the other estimators examined when the disturbances are non-normal. The experiments also indicate that one should liberally add points of support to the discrete factor distribution. The paper concludes with an application of the discrete factor approximation to the estimation of the impact of marriage on wages.

Continuous variable transmission and regenerative braking devices in bicycles utilizing magnetorheological fluids

NASA Astrophysics Data System (ADS)

Cheung, Wai Ming; Liao, Wei-Hsin

2013-04-01

The use of magnetorheological (MR) fluids in vehicles has been gaining popular recently due to its controllable nature, which gives automotive designers more dimensions of freedom in functional designs. However, not much attention has been paid to apply it to bicycles. This paper is aimed to study the feasibility of applying MR fluids in different dynamic parts of a bicycle such as the transmission and braking systems. MR continuous variable transmission (CVT) and power generator assisted in braking systems were designed and analyzed. Both prototypes were fabricated and tested to evaluate their performances. Experimental results showed that the proposed designs are promising to be used in bicycles.

New supervised learning theory applied to cerebellar modeling for suppression of variability of saccade end points.

PubMed

Fujita, Masahiko

2013-06-01

A new supervised learning theory is proposed for a hierarchical neural network with a single hidden layer of threshold units, which can approximate any continuous transformation, and applied to a cerebellar function to suppress the end-point variability of saccades. In motor systems, feedback control can reduce noise effects if the noise is added in a pathway from a motor center to a peripheral effector; however, it cannot reduce noise effects if the noise is generated in the motor center itself: a new control scheme is necessary for such noise. The cerebellar cortex is well known as a supervised learning system, and a novel theory of cerebellar cortical function developed in this study can explain the capability of the cerebellum to feedforwardly reduce noise effects, such as end-point variability of saccades. This theory assumes that a Golgi-granule cell system can encode the strength of a mossy fiber input as the state of neuronal activity of parallel fibers. By combining these parallel fiber signals with appropriate connection weights to produce a Purkinje cell output, an arbitrary continuous input-output relationship can be obtained. By incorporating such flexible computation and learning ability in a process of saccadic gain adaptation, a new control scheme in which the cerebellar cortex feedforwardly suppresses the end-point variability when it detects a variation in saccadic commands can be devised. Computer simulation confirmed the efficiency of such learning and showed a reduction in the variability of saccadic end points, similar to results obtained from experimental data.

Timing at peak force may be the hidden target controlled in continuation and synchronization tapping.

PubMed

Du, Yue; Clark, Jane E; Whitall, Jill

2017-05-01

Timing control, such as producing movements at a given rate or synchronizing movements to an external event, has been studied through a finger-tapping task where timing is measured at the initial contact between finger and tapping surface or the point when a key is pressed. However, the point of peak force is after the time registered at the tapping surface and thus is a less obvious but still an important event during finger tapping. Here, we compared the time at initial contact with the time at peak force as participants tapped their finger on a force sensor at a given rate after the metronome was turned off (continuation task) or in synchrony with the metronome (sensorimotor synchronization task). We found that, in the continuation task, timing was comparably accurate between initial contact and peak force. These two timing events also exhibited similar trial-by-trial statistical dependence (i.e., lag-one autocorrelation). However, the central clock variability was lower at the peak force than the initial contact. In the synchronization task, timing control at peak force appeared to be less variable and more accurate than that at initial contact. In addition to lower central clock variability, the mean SE magnitude at peak force (SEP) was around zero while SE at initial contact (SEC) was negative. Although SEC and SEP demonstrated the same trial-by-trial statistical dependence, we found that participants adjusted the time of tapping to correct SEP, but not SEC, toward zero. These results suggest that timing at peak force is a meaningful target of timing control, particularly in synchronization tapping. This result may explain the fact that SE at initial contact is typically negative as widely observed in the preexisting literature.

Continuous positive airway pressure improves gait control in severe obstructive sleep apnoea: A prospective study

PubMed Central

Wuyam, Bernard; Pépin, Jean-Louis; Marillier, Mathieu; Tamisier, Renaud; Pérennou, Dominic; Verges, Samuel

2018-01-01

Study aim Severe obstructive sleep apnoea (OSA) can lead to neurocognitive alterations, including gait impairments. The beneficial effects of continuous positive airway pressure (CPAP) on improving excessive daytime sleepiness and daily functioning have been documented. However, a demonstration of CPAP treatment efficacy on gait control is still lacking. This study aims to test the hypothesis that CPAP improves gait control in severe OSA patients. Material and methods In this prospective controlled study, twelve severe OSA patients (age = 57.2±8.9 years, body mass index = 27.4±3.1 kg·m-2, apnoea-hypopnoea index = 46.3±11.7 events·h-1) and 10 healthy matched subjects were included. Overground gait parameters were recorded at spontaneous speed and stride time variability, a clinical marker of gait control, was calculated. To assess the role of executive functions in gait and postural control, a dual-task paradigm was applied using a Stroop test as secondary cognitive task. All assessments were performed before and after 8 weeks of CPAP treatment. Results Before CPAP treatment, OSA patients had significantly larger stride time variability (3.1±1.1% vs 2.1±0.5%) and lower cognitive performances under dual task compared to controls. After CPAP treatment, stride time variability was significantly improved and no longer different compared to controls. Cognitive performance under dual task also improved after CPAP treatment. Conclusion Eight weeks of CPAP treatment improves gait control of severe OSA patients, suggesting morphological and functional cerebral improvements. Our data provide a rationale for further mechanistic studies and the use of gait as a biomarker of OSA brain consequences. PMID:29474363

An involuntary stereotypical grasp tendency pervades voluntary dynamic multifinger manipulation

PubMed Central

Rácz, Kornelius; Brown, Daniel

2012-01-01

We used a novel apparatus with three hinged finger pads to characterize collaborative multifinger interactions during dynamic manipulation requiring individuated control of fingertip motions and forces. Subjects placed the thumb, index, and middle fingertips on each hinged finger pad and held it—unsupported—with constant total grasp force while voluntarily oscillating the thumb's pad. This task combines the need to 1) hold the object against gravity while 2) dynamically reconfiguring the grasp. Fingertip force variability in this combined motion and force task exhibited strong synchrony among normal (i.e., grasp) forces. Mechanical analysis and simulation show that such synchronous variability is unnecessary and cannot be explained solely by signal-dependent noise. Surprisingly, such variability also pervaded control tasks requiring different individuated fingertip motions and forces, but not tasks without finger individuation such as static grasp. These results critically extend notions of finger force variability by exposing and quantifying a pervasive challenge to dynamic multifinger manipulation: the need for the neural controller to carefully and continuously overlay individuated finger actions over mechanically unnecessary synchronous interactions. This is compatible with—and may explain—the phenomenology of strong coupling of hand muscles when this delicate balance is not yet developed, as in early childhood, or when disrupted, as in brain injury. We conclude that the control of healthy multifinger dynamic manipulation has barely enough neuromechanical degrees of freedom to meet the multiple demands of ecological tasks and critically depends on the continuous inhibition of synchronous grasp tendencies, which we speculate may be of vestigial evolutionary origin. PMID:22956798

Family climates: family factors specific to disturbed eating and bulimia nervosa.

PubMed

Laliberté, M; Boland, F J; Leichner, P

1999-09-01

More than a decade of research has characterized the families of individuals with bulimia and bulimia anorexia (Anorexia Nervosa, Binge/Purging Type) as less expressive, less cohesive, and experiencing more conflicts than normal control families. This two-part study investigated variables believed more directly related to disturbed eating and bulimia as contributing to a "family climate for eating disorders." In Study 1. a nonclinical sample of 324 women who had just left home for college and a sample of 121 mothers evaluated their families. Principal-components analyses revealed the same factor structure for both students and mothers, with Family Body Satisfaction, Family Social Appearance Orientation, and Family Achievement Emphasis loading together, representing the hypothesized family climate for eating disorders: the remaining variables loaded with the more traditional family process variables (conflict, cohesion, expressiveness), representing a more general family dysfunction. As predicted, the family climate for eating disorders factor score was a more powerful predictor of disturbed eating. Study 2 extended these findings into a clin ical population, examining whether the family climate for eating disorders variables would distinguish individuals with bulimia from both depressed and healthy controls. Groups of eating-disordered patients (n = 40) and depressed (n = 17) and healthy (n = 27) controls completed family measures. The eating-disordered group scored significantly higher on family climate variables than control groups. Family process variables distinguished clinical groups (depressed and eating disordered) from healthy controls, but not from one another. Controlling for depression removed group differences on family process variables, but family climate variables continued to distinguish the eating-disordered group from both control groups. Indications for further research are discussed.

Static and Dynamic Aeroelastic Tailoring With Variable Camber Control

NASA Technical Reports Server (NTRS)

Stanford, Bret K.

2016-01-01

This paper examines the use of a Variable Camber Continuous Trailing Edge Flap (VCCTEF) system for aeroservoelastic optimization of a transport wingbox. The quasisteady and unsteady motions of the flap system are utilized as design variables, along with patch-level structural variables, towards minimizing wingbox weight via maneuver load alleviation and active flutter suppression. The resulting system is, in general, very successful at removing structural weight in a feasible manner. Limitations to this success are imposed by including load cases where the VCCTEF system is not active (open-loop) in the optimization process, and also by including actuator operating cost constraints.

Size variability of the unit building block of peripheral light-harvesting antennas as a strategy for effective functioning of antennas of variable size that is controlled in vivo by light intensity.

PubMed

Taisova, A S; Yakovlev, A G; Fetisova, Z G

2014-03-01

This work continuous a series of studies devoted to discovering principles of organization of natural antennas in photosynthetic microorganisms that generate in vivo large and highly effective light-harvesting structures. The largest antenna is observed in green photosynthesizing bacteria, which are able to grow over a wide range of light intensities and adapt to low intensities by increasing of size of peripheral BChl c/d/e antenna. However, increasing antenna size must inevitably cause structural changes needed to maintain high efficiency of its functioning. Our model calculations have demonstrated that aggregation of the light-harvesting antenna pigments represents one of the universal structural factors that optimize functioning of any antenna and manage antenna efficiency. If the degree of aggregation of antenna pigments is a variable parameter, then efficiency of the antenna increases with increasing size of a single aggregate of the antenna. This means that change in degree of pigment aggregation controlled by light-harvesting antenna size is biologically expedient. We showed in our previous work on the oligomeric chlorosomal BChl c superantenna of green bacteria of the Chloroflexaceae family that this principle of optimization of variable antenna structure, whose size is controlled by light intensity during growth of bacteria, is actually realized in vivo. Studies of this phenomenon are continued in the present work, expanding the number of studied biological materials and investigating optical linear and nonlinear spectra of chlorosomes having different structures. We show for oligomeric chlorosomal superantennas of green bacteria (from two different families, Chloroflexaceae and Oscillochloridaceae) that a single BChl c aggregate is of small size, and the degree of BChl c aggregation is a variable parameter, which is controlled by the size of the entire BChl c superantenna, and the latter, in turn, is controlled by light intensity in the course of cell culture growth.

Continuous-variable geometric phase and its manipulation for quantum computation in a superconducting circuit.

PubMed

Song, Chao; Zheng, Shi-Biao; Zhang, Pengfei; Xu, Kai; Zhang, Libo; Guo, Qiujiang; Liu, Wuxin; Xu, Da; Deng, Hui; Huang, Keqiang; Zheng, Dongning; Zhu, Xiaobo; Wang, H

2017-10-20

Geometric phase, associated with holonomy transformation in quantum state space, is an important quantum-mechanical effect. Besides fundamental interest, this effect has practical applications, among which geometric quantum computation is a paradigm, where quantum logic operations are realized through geometric phase manipulation that has some intrinsic noise-resilient advantages and may enable simplified implementation of multi-qubit gates compared to the dynamical approach. Here we report observation of a continuous-variable geometric phase and demonstrate a quantum gate protocol based on this phase in a superconducting circuit, where five qubits are controllably coupled to a resonator. Our geometric approach allows for one-step implementation of n-qubit controlled-phase gates, which represents a remarkable advantage compared to gate decomposition methods, where the number of required steps dramatically increases with n. Following this approach, we realize these gates with n up to 4, verifying the high efficiency of this geometric manipulation for quantum computation.

Flight data analysis and further development of variable-conductance heat pipes. [for aircraft control

NASA Technical Reports Server (NTRS)

Enginer, J. E.; Luedke, E. E.; Wanous, D. J.

1976-01-01

Continuing efforts in large gains in heat-pipe performance are reported. It was found that gas-controlled variable-conductance heat pipes can perform reliably for long periods in space and effectively provide temperature stabilization for spacecraft electronics. A solution was formulated that allows the control gas to vent through arterial heat-pipe walls, thus eliminating the problem of arterial failure under load, due to trace impurities of noncondensable gas trapped in an arterial bubble during priming. This solution functions well in zero gravity. Another solution was found that allows priming at a much lower fluid charge. A heat pipe with high capacity, with close temperature control of the heat source and independent of large variations in sink temperature was fabricated.

Multi-scale evaluation of the environmental controls on burn probability in a southern Sierra Nevada landscape

Treesearch

Sean A. Parks; Marc-Andre Parisien; Carol Miller

2011-01-01

We examined the scale-dependent relationship between spatial fire likelihood or burn probability (BP) and some key environmental controls in the southern Sierra Nevada, California, USA. Continuous BP estimates were generated using a fire simulation model. The correspondence between BP (dependent variable) and elevation, ignition density, fuels and aspect was evaluated...

Evaluation of trunk injections for control of emerald ash borer

Treesearch

Deborah G. McCullough; Therese M. Poland; David L. Cappaert; Phillip Lewis; John Molongowski

2005-01-01

In 2003, we evaluated trunk injections of imidacloprid for control of emerald ash borer (Agrilus planipennis Fairmaire) (EAB). Results were variable and indicated that efficacy could be affected by injection timing and method and by tree size and vigor. In 2004, we continued studies to assess the optimal timing for imidacloprid trunk injections and...

Method of operating an oil shale kiln

DOEpatents

Reeves, Adam A.

1978-05-23

Continuously determining the bulk density of raw and retorted oil shale, the specific gravity of the raw oil shale and the richness of the raw oil shale provides accurate means to control process variables of the retorting of oil shale, predicting oil production, determining mining strategy, and aids in controlling shale placement in the kiln for the retorting.

Perceptions of control in adults with epilepsy.

PubMed

Gehlert, S

1994-01-01

That psychosocial problems are extant in epilepsy is evidenced by a suicide rate among epileptic persons five times that of the general population and an unemployment rate estimated to be more than twice that of the population as a whole. External perceptions of control secondary to repeated episodes of seizure activity that generalize to the social sphere have been implicated as causes of these problems. The hypothesis that individuals who continue to have seizures become more and more external in perceptions of control was tested by a survey mailed to a sample of individuals with epilepsy in a metropolitan area of the Midwest. Dependent variables were, scores on instruments measuring locus of control and attributional style. The independent variable was a measure of seizure control based on present age, age at onset, and length of time since last seizure. Gender, socioeconomic status, and certain parenting characteristics were included as control variables, as they are also known to affect perceptions of control. Analysis by multiple regression techniques supported the study's hypothesis when perceptions of control was conceptualized as learned helplessness for bad, but not for good, events. The hypothesis was not confirmed when perceptions of control was conceptualized as either general or health locus of control.

Bubble CPAP versus CPAP with variable flow in newborns with respiratory distress: a randomized controlled trial.

PubMed

Yagui, Ana Cristina Zanon; Vale, Luciana Assis Pires Andrade; Haddad, Luciana Branco; Prado, Cristiane; Rossi, Felipe Souza; Deutsch, Alice D Agostini; Rebello, Celso Moura

2011-01-01

To evaluate the efficacy and safety of nasal continuous positive airway pressure (NCPAP) using devices with variable flow or bubble continuous positive airway pressure (CPAP) regarding CPAP failure, presence of air leaks, total CPAP and oxygen time, and length of intensive care unit and hospital stay in neonates with moderate respiratory distress (RD) and birth weight (BW) ≥ 1,500 g. Forty newborns requiring NCPAP were randomized into two study groups: variable flow group (VF) and continuous flow group (CF). The study was conducted between October 2008 and April 2010. Demographic data, CPAP failure, presence of air leaks, and total CPAP and oxygen time were recorded. Categorical outcomes were tested using the chi-square test or the Fisher's exact test. Continuous variables were analyzed using the Mann-Whitney test. The level of significance was set at p < 0.05. There were no differences between the groups with regard to demographic data, CPAP failure (21.1 and 20.0% for VF and CF, respectively; p = 1.000), air leak syndrome (10.5 and 5.0%, respectively; p = 0.605), total CPAP time (median: 22.0 h, interquartile range [IQR]: 8.00-31.00 h and median: 22.0 h, IQR: 6.00-32.00 h, respectively; p = 0.822), and total oxygen time (median: 24.00 h, IQR: 7.00-85.00 h and median: 21.00 h, IQR: 9.50-66.75 h, respectively; p = 0.779). In newborns with BW ≥ 1,500 g and moderate RD, the use of continuous flow NCPAP showed the same benefits as the use of variable flow NCPAP.

Negative control exposure studies in the presence of measurement error: implications for attempted effect estimate calibration

PubMed Central

Sanderson, Eleanor; Macdonald-Wallis, Corrie; Davey Smith, George

2018-01-01

Abstract Background Negative control exposure studies are increasingly being used in epidemiological studies to strengthen causal inference regarding an exposure-outcome association when unobserved confounding is thought to be present. Negative control exposure studies contrast the magnitude of association of the negative control, which has no causal effect on the outcome but is associated with the unmeasured confounders in the same way as the exposure, with the magnitude of the association of the exposure with the outcome. A markedly larger effect of the exposure on the outcome than the negative control on the outcome strengthens inference that the exposure has a causal effect on the outcome. Methods We investigate the effect of measurement error in the exposure and negative control variables on the results obtained from a negative control exposure study. We do this in models with continuous and binary exposure and negative control variables using analysis of the bias of the estimated coefficients and Monte Carlo simulations. Results Our results show that measurement error in either the exposure or negative control variables can bias the estimated results from the negative control exposure study. Conclusions Measurement error is common in the variables used in epidemiological studies; these results show that negative control exposure studies cannot be used to precisely determine the size of the effect of the exposure variable, or adequately adjust for unobserved confounding; however, they can be used as part of a body of evidence to aid inference as to whether a causal effect of the exposure on the outcome is present. PMID:29088358

Negative control exposure studies in the presence of measurement error: implications for attempted effect estimate calibration.

PubMed

Sanderson, Eleanor; Macdonald-Wallis, Corrie; Davey Smith, George

2018-04-01

Negative control exposure studies are increasingly being used in epidemiological studies to strengthen causal inference regarding an exposure-outcome association when unobserved confounding is thought to be present. Negative control exposure studies contrast the magnitude of association of the negative control, which has no causal effect on the outcome but is associated with the unmeasured confounders in the same way as the exposure, with the magnitude of the association of the exposure with the outcome. A markedly larger effect of the exposure on the outcome than the negative control on the outcome strengthens inference that the exposure has a causal effect on the outcome. We investigate the effect of measurement error in the exposure and negative control variables on the results obtained from a negative control exposure study. We do this in models with continuous and binary exposure and negative control variables using analysis of the bias of the estimated coefficients and Monte Carlo simulations. Our results show that measurement error in either the exposure or negative control variables can bias the estimated results from the negative control exposure study. Measurement error is common in the variables used in epidemiological studies; these results show that negative control exposure studies cannot be used to precisely determine the size of the effect of the exposure variable, or adequately adjust for unobserved confounding; however, they can be used as part of a body of evidence to aid inference as to whether a causal effect of the exposure on the outcome is present.

Development of Variable Camber Continuous Trailing Edge Flap for Performance Adaptive Aeroelastic Wing

NASA Technical Reports Server (NTRS)

Nguyen, Nhan; Kaul, Upender; Lebofsky, Sonia; Ting, Eric; Chaparro, Daniel; Urnes, James

2015-01-01

This paper summarizes the recent development of an adaptive aeroelastic wing shaping control technology called variable camber continuous trailing edge flap (VCCTEF). As wing flexibility increases, aeroelastic interactions with aerodynamic forces and moments become an increasingly important consideration in aircraft design and aerodynamic performance. Furthermore, aeroelastic interactions with flight dynamics can result in issues with vehicle stability and control. The initial VCCTEF concept was developed in 2010 by NASA under a NASA Innovation Fund study entitled "Elastically Shaped Future Air Vehicle Concept," which showed that highly flexible wing aerodynamic surfaces can be elastically shaped in-flight by active control of wing twist and bending deflection in order to optimize the spanwise lift distribution for drag reduction. A collaboration between NASA and Boeing Research & Technology was subsequently funded by NASA from 2012 to 2014 to further develop the VCCTEF concept. This paper summarizes some of the key research areas conducted by NASA during the collaboration with Boeing Research and Technology. These research areas include VCCTEF design concepts, aerodynamic analysis of VCCTEF camber shapes, aerodynamic optimization of lift distribution for drag minimization, wind tunnel test results for cruise and high-lift configurations, flutter analysis and suppression control of flexible wing aircraft, and multi-objective flight control for adaptive aeroelastic wing shaping control.

Modeling continuous covariates with a "spike" at zero: Bivariate approaches.

PubMed

Jenkner, Carolin; Lorenz, Eva; Becher, Heiko; Sauerbrei, Willi

2016-07-01

In epidemiology and clinical research, predictors often take value zero for a large amount of observations while the distribution of the remaining observations is continuous. These predictors are called variables with a spike at zero. Examples include smoking or alcohol consumption. Recently, an extension of the fractional polynomial (FP) procedure, a technique for modeling nonlinear relationships, was proposed to deal with such situations. To indicate whether or not a value is zero, a binary variable is added to the model. In a two stage procedure, called FP-spike, the necessity of the binary variable and/or the continuous FP function for the positive part are assessed for a suitable fit. In univariate analyses, the FP-spike procedure usually leads to functional relationships that are easy to interpret. This paper introduces four approaches for dealing with two variables with a spike at zero (SAZ). The methods depend on the bivariate distribution of zero and nonzero values. Bi-Sep is the simplest of the four bivariate approaches. It uses the univariate FP-spike procedure separately for the two SAZ variables. In Bi-D3, Bi-D1, and Bi-Sub, proportions of zeros in both variables are considered simultaneously in the binary indicators. Therefore, these strategies can account for correlated variables. The methods can be used for arbitrary distributions of the covariates. For illustration and comparison of results, data from a case-control study on laryngeal cancer, with smoking and alcohol intake as two SAZ variables, is considered. In addition, a possible extension to three or more SAZ variables is outlined. A combination of log-linear models for the analysis of the correlation in combination with the bivariate approaches is proposed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Field demonstration of a continuous-variable quantum key distribution network.

PubMed

Huang, Duan; Huang, Peng; Li, Huasheng; Wang, Tao; Zhou, Yingming; Zeng, Guihua

2016-08-01

We report on what we believe is the first field implementation of a continuous-variable quantum key distribution (CV-QKD) network with point-to-point configuration. Four QKD nodes are deployed on standard communication infrastructures connected with commercial telecom optical fiber. Reliable key exchange is achieved in the wavelength-division-multiplexing CV-QKD network. The impact of a complex and volatile field environment on the excess noise is investigated, since excess noise controlling and reduction is arguably the major issue pertaining to distance and the secure key rate. We confirm the applicability and verify the maturity of the CV-QKD network in a metropolitan area, thus paving the way for a next-generation global secure communication network.

Continuous-variable quantum key distribution with 1 Mbps secure key rate.

PubMed

Huang, Duan; Lin, Dakai; Wang, Chao; Liu, Weiqi; Fang, Shuanghong; Peng, Jinye; Huang, Peng; Zeng, Guihua

2015-06-29

We report the first continuous-variable quantum key distribution (CVQKD) experiment to enable the creation of 1 Mbps secure key rate over 25 km standard telecom fiber in a coarse wavelength division multiplexers (CWDM) environment. The result is achieved with two major technological advances: the use of a 1 GHz shot-noise-limited homodyne detector and the implementation of a 50 MHz clock system. The excess noise due to noise photons from local oscillator and classical data channels in CWDM is controlled effectively. We note that the experimental verification of high-bit-rate CVQKD in the multiplexing environment is a significant step closer toward large-scale deployment in fiber networks.

The effects of free-living interval-walking training on glycemic control, body composition, and physical fitness in type 2 diabetic patients: a randomized, controlled trial.

PubMed

Karstoft, Kristian; Winding, Kamilla; Knudsen, Sine H; Nielsen, Jens S; Thomsen, Carsten; Pedersen, Bente K; Solomon, Thomas P J

2013-02-01

To evaluate the feasibility of free-living walking training in type 2 diabetic patients and to investigate the effects of interval-walking training versus continuous-walking training upon physical fitness, body composition, and glycemic control. Subjects with type 2 diabetes were randomized to a control (n = 8), continuous-walking (n = 12), or interval-walking group (n = 12). Training groups were prescribed five sessions per week (60 min/session) and were controlled with an accelerometer and a heart-rate monitor. Continuous walkers performed all training at moderate intensity, whereas interval walkers alternated 3-min repetitions at low and high intensity. Before and after the 4-month intervention, the following variables were measured: VO(2)max, body composition, and glycemic control (fasting glucose, HbA(1c), oral glucose tolerance test, and continuous glucose monitoring [CGM]). Training adherence was high (89 ± 4%), and training energy expenditure and mean intensity were comparable. VO(2)max increased 16.1 ± 3.7% in the interval-walking group (P < 0.05), whereas no changes were observed in the continuous-walking or control group. Body mass and adiposity (fat mass and visceral fat) decreased in the interval-walking group only (P < 0.05). Glycemic control (elevated mean CGM glucose levels and increased fasting insulin) worsened in the control group (P < 0.05), whereas mean (P = 0.05) and maximum (P < 0.05) CGM glucose levels decreased in the interval-walking group. The continuous walkers showed no changes in glycemic control. Free-living walking training is feasible in type 2 diabetic patients. Continuous walking offsets the deterioration in glycemia seen in the control group, and interval walking is superior to energy expenditure-matched continuous walking for improving physical fitness, body composition, and glycemic control.

Simulation to coating weight control for galvanizing

NASA Astrophysics Data System (ADS)

Wang, Junsheng; Yan, Zhang; Wu, Kunkui; Song, Lei

2013-05-01

Zinc coating weight control is one of the most critical issues for continuous galvanizing line. The process has the characteristic of variable-time large time delay, nonlinear, multivariable. It can result in seriously coating weight error and non-uniform coating. We develop a control system, which can automatically control the air knives pressure and its position to give a constant and uniform zinc coating, in accordance with customer-order specification through an auto-adaptive empirical model-based feed forward adaptive controller, and two model-free adaptive feedback controllers . The proposed models with controller were applied to continuous galvanizing line (CGL) at Angang Steel Works. By the production results, the precise and stability of the control model reduces over-coating weight and improves coating uniform. The product for this hot dip galvanizing line does not only satisfy the customers' quality requirement but also save the zinc consumption.

Automotive sensors: past, present and future

NASA Astrophysics Data System (ADS)

Prosser, S. J.

2007-07-01

This paper will provide a review of past, present and future automotive sensors. Today's vehicles have become highly complex sophisticated electronic control systems and the majority of innovations have been solely achieved through electronics and the use of advanced sensors. A range of technologies have been used over the past twenty years including silicon microengineering, thick film, capacitive, variable reluctance, optical and radar. The automotive sensor market continues to grow with respect to vehicle production level in recognition of the transition to electronically controlled electrically actuated systems. The environment for these sensors continues to be increasingly challenging with respect to robustness, reliability, quality and cost.

Action Control, Motivated Strategies, and Integrative Motivation as Predictors of Language Learning Affect and the Intention to Continue Learning French

ERIC Educational Resources Information Center

MacIntyre, Peter D.; Blackie, Rebecca A.

2012-01-01

The present study examines the relative ability of variables from three motivational frameworks to predict four non-linguistic outcomes of language learning. The study examines Action Control Theory with its measures of (1) hesitation, (2) volatility and (3) rumination. The study also examined Pintrich's expectancy-value model that uses measures…

Life extending control: An interdisciplinary engineering thrust

NASA Technical Reports Server (NTRS)

Lorenzo, Carl F.; Merrill, Walter C.

1991-01-01

The concept of Life Extending Control (LEC) is introduced. Possible extensions to the cyclic damage prediction approach are presented based on the identification of a model from elementary forms. Several candidate elementary forms are presented. These extensions will result in a continuous or differential form of the damage prediction model. Two possible approaches to the LEC based on the existing cyclic damage prediction method, the measured variables LEC and the estimated variables LEC, are defined. Here, damage estimates or measurements would be used directly in the LEC. A simple hydraulic actuator driven position control system example is used to illustrate the main ideas behind LEC. Results from a simple hydraulic actuator example demonstrate that overall system performance (dynamic plus life) can be maximized by accounting for component damage in the control design.

Use of clay to remediate cadmium contaminated soil under different water management regimes.

PubMed

Li, Jianrui; Xu, Yingming

2017-07-01

We examined in situ remediation of sepiolite on cadmium-polluted soils with diverse water regimes, and several variables including brown rice Cd, exchangeable Cd, pH, and available Fe/P. pH, available Fe/P in soils increased gradually during continuous flooding, which contributed to Cd absorption on colloids. In control group (untreated soils), compared to conventional irrigation, brown rice Cd in continuous flooding reduced by 37.9%, and that in wetting irrigation increased by 31.0% (p<0.05). In contrast to corresponding controls, brown rice Cd in sepiolite treated soils reduced by 44.4%, 34.5% and 36.8% under continuous flooding, conventional irrigation and wetting irrigation (p<0.05), and exchangeable Cd in amended soils reduced by 27.5-49.0%, 14.3-40.5%, and 24.9-32.8% under three water management regimes (p<0.05). Compared to corresponding controls, decreasing amplitudes of exchangeable Cd and brown rice Cd in sepiolite treated soils were higher in continuous flooding than in conventional irrigation and wetting irrigation. Continuous flooding management promoted soil Cd immobilization by sepiolite. Copyright © 2017. Published by Elsevier Inc.

Glucose-lowering effect and glycaemic variability of insulin glargine, insulin detemir and insulin lispro protamine in people with type 1 diabetes.

PubMed

Derosa, G; Franzetti, I; Querci, F; Romano, D; D'Angelo, A; Maffioli, P

2015-06-01

To compare, using a continuous glucose monitoring (CGM) system, the effect on glycaemic variability of insulin glargine, detemir and lispro protamine. A total of 49 white people with type 1 diabetes, not well controlled by three times daily insulin lispro, taken for at least 2 months before study and on a stable dose, were enrolled. The study participants were randomized to add insulin glargine, detemir or lispro protamine, once daily, in the evening. We used a CGM system, the iPro Digital Recorder (Medtronic MiniMed, Northridge, CA, USA) for 1 week. Glycaemic control was assessed according to mean blood glucose values, the area under the glucose curve above 3.9 mmol/l (AUC(>3.9)) or above 10.0 mmol/l (AUC(>10.0)), and the percentage of time spent with glucose values >3.9 or >10.0 mmol/l. Intraday glycaemic variability was assessed using standard deviation (s.d.) values, the mean amplitude of glycaemic excursions and continuous overlapping of net glycaemic action. Day-to-day glycaemic variability was assessed using the mean of daily differences. The s.d. was found to be significantly lower with insulin lispro protamine and glargine compared with insulin detemir. AUC(>3.9) was higher and AUC(>10.0) was lower with insulin lispro protamine and glargine compared with detemir. The mean amplitude of glycaemic excursions and continuous overlapping net glycaemic action values were lower with insulin lispro protamine and glargine compared with detemir. In addition, the mean of daily differences was significantly lower with insulin lispro protamine and glargine compared with detemir. Fewer hypoglycaemic events were recorded during the night-time with insulin lispro protamine compared with glargine and detemir. The results suggest that insulin lispro protamine and glargine are more effective than detemir in reducing glycaemic variability and improving glycaemic control in people with type 1 diabetes. Insulin lispro protamine seems to lead to fewer hypoglycaemic events than other insulin regimens. © 2015 John Wiley & Sons Ltd.

Association between resilience and posttraumatic stress disorder among Brazilian victims of urban violence: a cross-sectional case-control study.

PubMed

Teche, Stefania Pigatto; Barros, Alcina Juliana Soares; Rosa, Regis Goulart; Guimarães, Luciano Pinto; Cordini, Kariny Larissa; Goi, Julia Domingues; Hauck, Simone; Freitas, Lucia Helena

2017-01-01

This study investigated the association between resilience and posttraumatic stress disorder (PTSD) among Brazilian victims of urban violence. It also compared defense mechanisms, parental bonding, and childhood trauma between those who developed PTSD and those who did not. This cross-sectional case-control study included 66 adult subjects exposed to recent urban violence in southern Brazil - 33 with PTSD and 33 healthy controls matched by sex and age - who were administered the Resilience Scale, Defense Style Questionnaire, Parental Bonding Instrument, and Childhood Trauma Questionnaire. The statistical tests used were the McNemar test for categorical variables, the Wilcoxon signed-rank test for continuous asymmetric variables, and the paired Student t-test for continuous symmetric variables. The PTSD group showed lower total Resilience Scale scores compared with controls (128.4±20.7 vs. 145.8±13.1, respectively; p = 0.01), along with a lower ability to solve situations and lower personal values that give meaning to life (p = 0.019). They also had lower rates of mature defense mechanisms (p < 0.001) and higher rates of emotional (p = 0.001) and physical (p = 0.003) abuse during childhood. Lower levels of resilience, especially the ability to solve situations and having personal values that give meaning to life, immature defense mechanisms, and emotional and physical abuse in childhood are associated with PTSD in adult Brazilian victims of urban violence.

Motion makes sense: an adaptive motor-sensory strategy underlies the perception of object location in rats.

PubMed

Saraf-Sinik, Inbar; Assa, Eldad; Ahissar, Ehud

2015-06-10

Tactile perception is obtained by coordinated motor-sensory processes. We studied the processes underlying the perception of object location in freely moving rats. We trained rats to identify the relative location of two vertical poles placed in front of them and measured at high resolution the motor and sensory variables (19 and 2 variables, respectively) associated with this whiskers-based perceptual process. We found that the rats developed stereotypic head and whisker movements to solve this task, in a manner that can be described by several distinct behavioral phases. During two of these phases, the rats' whiskers coded object position by first temporal and then angular coding schemes. We then introduced wind (in two opposite directions) and remeasured their perceptual performance and motor-sensory variables. Our rats continued to perceive object location in a consistent manner under wind perturbations while maintaining all behavioral phases and relatively constant sensory coding. Constant sensory coding was achieved by keeping one group of motor variables (the "controlled variables") constant, despite the perturbing wind, at the cost of strongly modulating another group of motor variables (the "modulated variables"). The controlled variables included coding-relevant variables, such as head azimuth and whisker velocity. These results indicate that consistent perception of location in the rat is obtained actively, via a selective control of perception-relevant motor variables. Copyright © 2015 the authors 0270-6474/15/358777-13$15.00/0.

Effects of local and widespread muscle fatigue on movement timing.

PubMed

Cowley, Jeffrey C; Dingwell, Jonathan B; Gates, Deanna H

2014-12-01

Repetitive movements can cause muscle fatigue, leading to motor reorganization, performance deficits, and/or possible injury. The effects of fatigue may depend on the type of fatigue task employed, however. The purpose of this study was to determine how local fatigue of a specific muscle group versus widespread fatigue of various muscle groups affected the control of movement timing. Twenty healthy subjects performed an upper extremity low-load work task similar to sawing for 5 continuous minutes both before and after completing a protocol that either fatigued all the muscles used in the task (widespread fatigue) or a protocol that selectively fatigued the primary muscles used to execute the pushing stroke of the sawing task (localized fatigue). Subjects were instructed to time their movements with a metronome. Timing error, movement distance, and speed were calculated for each movement. Data were then analyzed using a goal-equivalent manifold approach to quantify changes in goal-relevant and non-goal-relevant variability. We applied detrended fluctuation analysis to each time series to quantify changes in fluctuation dynamics that reflected changes in the control strategies used. After localized fatigue, subjects made shorter, slower movements and exerted greater control over non-goal-relevant variability. After widespread fatigue, subjects exerted less control over non-goal-relevant variability and did not change movement patterns. Thus, localized and widespread muscle fatigue affected movement differently. Local fatigue may reduce the available motor solutions and therefore cause greater movement reorganization than widespread muscle fatigue. Subjects altered their control strategies but continued to achieve the timing goal after both fatigue tasks.

Pulsatile support using a rotary left ventricular assist device with an electrocardiography-synchronized rotational speed control mode for tracking heart rate variability.

PubMed

Arakawa, Mamoru; Nishimura, Takashi; Takewa, Yoshiaki; Umeki, Akihide; Ando, Masahiko; Kishimoto, Yuichiro; Kishimoto, Satoru; Fujii, Yutaka; Date, Kazuma; Kyo, Shunei; Adachi, Hideo; Tatsumi, Eisuke

2016-06-01

We previously developed a novel control system for a continuous-flow left ventricular assist device (LVAD), the EVAHEART, and demonstrated that sufficient pulsatility can be created by increasing its rotational speed in the systolic phase (pulsatile mode) in a normal heart animal model. In the present study, we assessed this system in its reliability and ability to follow heart rate variability. We implanted an EVAHEART via left thoracotomy into five goats for the Study for Fixed Heart Rate with ventricular pacing at 80, 100, 120 and 140 beats/min and six goats for the Study for native heart rhythm. We tested three modes: the circuit clamp, the continuous mode and the pulsatile mode. In the pulsatile mode, rotational speed was increased during the initial 35 % of the RR interval by automatic control based on the electrocardiogram. Pulsatility was evaluated by pulse pressure and dP/dt max of aortic pressure. As a result, comparing the pulsatile mode with the continuous mode, the pulse pressure was 28.5 ± 5.7 vs. 20.3 ± 7.9 mmHg, mean dP/dt max was 775.0 ± 230.5 vs 442.4 ± 184.7 mmHg/s at 80 bpm in the study for fixed heart rate, respectively (P < 0.05). The system successfully determined the heart rate to be 94.6 % in native heart rhythm. Furthermore, pulse pressure was 41.5 ± 7.9 vs. 27.8 ± 5.6 mmHg, mean dP/dt max was 716.2 ± 133.9 vs 405.2 ± 86.0 mmHg/s, respectively (P < 0.01). In conclusion, our newly developed the pulsatile mode for continuous-flow LVADs reliably provided physiological pulsatility with following heart rate variability.

Authoritative parenting style and adolescent smoking and drinking.

PubMed

Piko, Bettina F; Balázs, Máté Á

2012-03-01

While peer influences have often found to be a risk factor in terms of adolescent substance use, parental variables may continue to serve as an adaptive and protective function, although the role of parents is more latent and controversial. Therefore, the main goal of this paper was to investigate the role of authoritative parenting style and other family variables in adolescents' smoking and drinking. Using a sample of Hungarian youth (N=2072; age range between 12 and 22; Mean=15.4 years, S.D.=1.8 years; 49,2% males) logistic regression analyses confirmed that authoritative parenting style (particularly responsiveness) and positive identification with parents may serve as a protection, whereas negative family interactions may act as a risk factor. These relationships are particularly decisive in case of monthly prevalence of drinking and both lifetime and current prevalence of smoking. Gender differences are slight (namely, parental control for boys, whereas responsiveness for girls seem to be more relevant), however, the role of certain parental variables may change with age. Although parental control tends to decrease among high school students, it even serves as a greater protection for those whose parents continue providing parental monitoring. Copyright © 2011 Elsevier Ltd. All rights reserved.

Quantification of peripheral and central blood pressure variability using a time-frequency method.

PubMed

Kouchaki, Z; Butlin, M; Qasem, A; Avolio, A P

2016-08-01

Systolic blood pressure variability (BPV) is associated with cardiovascular events. As the beat-to-beat variation of blood pressure is due to interaction of several cardiovascular control systems operating with different response times, assessment of BPV by spectral analysis using the continuous measurement of arterial pressure in the finger is used to differentiate the contribution of these systems in regulating blood pressure. However, as baroreceptors are centrally located, this study considered applying a continuous aortic pressure signal estimated noninvasively from finger pressure for assessment of systolic BPV by a time-frequency method using Short Time Fourier Transform (STFT). The average ratio of low frequency and high frequency power band (LF PB /HF PB ) was computed by time-frequency decomposition of peripheral systolic pressure (pSBP) and derived central aortic systolic blood pressure (cSBP) in 30 healthy subjects (25-62 years) as a marker of balance between cardiovascular control systems contributing in low and high frequency blood pressure variability. The results showed that the BPV assessed from finger pressure (pBPV) overestimated the BPV values compared to that assessed from central aortic pressure (cBPV) for identical cardiac cycles (P<;0.001), with the overestimation being greater at higher power.

Optimal orbit transfer suitable for large flexible structures

NASA Technical Reports Server (NTRS)

Chatterjee, Alok K.

1989-01-01

The problem of continuous low-thrust planar orbit transfer of large flexible structures is formulated as an optimal control problem with terminal state constraints. The dynamics of the spacecraft motion are treated as a point-mass central force field problem; the thrust-acceleration magnitude is treated as an additional state variable; and the rate of change of thrust-acceleration is treated as a control variable. To ensure smooth transfer, essential for flexible structures, an additional quadratic term is appended to the time cost functional. This term penalizes any abrupt change in acceleration. Numerical results are presented for the special case of a planar transfer.

Heralded processes on continuous-variable spaces as quantum maps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferreyrol, Franck; Spagnolo, Nicolò; Blandino, Rémi

2014-12-04

Heralding processes, which only work when a measurement on a part of the system give the good result, are particularly interesting for continuous-variables. They permit non-Gaussian transformations that are necessary for several continuous-variable quantum information tasks. However if maps and quantum process tomography are commonly used to describe quantum transformations in discrete-variable space, they are much rarer in the continuous-variable domain. Also, no convenient tool for representing maps in a way more adapted to the particularities of continuous variables have yet been explored. In this paper we try to fill this gap by presenting such a tool.

Randomized, multicenter study: on-demand versus continuous maintenance treatment with esomeprazole in patients with non-erosive gastroesophageal reflux disease.

PubMed

Bayerdörffer, Ekkehard; Bigard, Marc-Andre; Weiss, Werner; Mearin, Fermín; Rodrigo, Luis; Dominguez Muñoz, Juan Enrique; Grundling, Hennie; Persson, Tore; Svedberg, Lars-Erik; Keeling, Nanna; Eklund, Stefan

2016-04-14

Most patients with gastroesophageal reflux disease experience symptomatic relapse after stopping acid-suppressive medication. The aim of this study was to compare willingness to continue treatment with esomeprazole on-demand versus continuous maintenance therapy for symptom control in patients with non-erosive reflux disease (NERD) after 6 months. This multicenter, open-label, randomized, parallel-group study enrolled adults with NERD who were heartburn-free after 4 weeks' treatment with esomeprazole 20 mg daily. Patients received esomeprazole 20 mg daily continuously or on-demand for 6 months. The primary variable was discontinuation due to unsatisfactory treatment. On-demand treatment was considered non-inferior if the upper limit of the one-sided 95 % confidence interval (CI) for the difference between treatments was <10 %. Of 877 patients enrolled, 598 were randomized to maintenance treatment (continuous: n = 297; on-demand: n = 301). Discontinuation due to unsatisfactory treatment was 6.3 % for on-demand and 9.8 % for continuous treatment (difference -3.5 % [90 % CI: -7.1 %, 0.2 %]). In total, 82.1 and 86.2 % of patients taking on-demand and continuous therapy, respectively, were satisfied with the treatment of heartburn and regurgitation symptoms, a secondary variable (P = NS). Mean study drug consumption was 0.41 and 0.91 tablets/day, respectively. Overall, 5 % of the on-demand group developed reflux esophagitis versus none in the continuous group (P < 0.0001). The Gastrointestinal Symptom Rating Scale Reflux dimension was also improved for continuous versus on-demand treatment. Esomeprazole was well tolerated. In terms of willingness to continue treatment, on-demand treatment with esomeprazole 20 mg was non-inferior to continuous maintenance treatment and reduced medication usage in patients with NERD who had achieved symptom control with initial esomeprazole treatment. ClinicalTrials.gov identifier (NCT number): NCT02670642 ; Date of registration: December 2015.

Efficacy of plasma-rich growth factor in the healing of postextraction sockets in patients affected by insulin-dependent diabetes mellitus.

PubMed

Mozzati, Marco; Gallesio, Giorgia; di Romana, Sara; Bergamasco, Laura; Pol, Renato

2014-03-01

To evaluate the efficacy of plasma-rich growth factor (PRGF) in improving socket healing after tooth extraction in diabetic patients. This was a split-mouth study in which each patient also served as the control: the study socket was treated with PRGF, whereas the control socket underwent natural healing. The outcome variables were the Healing Index, residual socket volume, visual analog scale score, postsurgical complications, and outcome of a patient questionnaire. The investigation considered the impact of hyperglycemia, glycated hemoglobin, End Organ Disease Score, and smoking habits. Follow-up included 4 postextraction checkups over a 21-day period. Pairs of correlated continuous variables were analyzed with the Wilcoxon test, independent continuous variables with the Mann-Whitney test, and categorical variables with the χ(2) test or Fisher test. From January 2012 to December 2012, 34 patients affected by insulin-dependent diabetes mellitus underwent contemporary bilateral extractions of homologous teeth. The treatment-versus-control postoperative comparison showed that PRGF resulted in significantly smaller residual socket volumes and better Healing Indices from days 3 to 14. The patients' questionnaire outcomes were unanimously in favor of PRGF treatment. The small sample of patients with glycemia values of at least 240 mg/dL showed worse Healing Index and minor socket decreases. PRGF application after extraction improved the healing process in diabetic patients by accelerating socket closure (epithelialization) and tissue maturation, proving the association between PRGF use and improved wound healing in diabetic patients. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Novel measures of response performance and inhibition in children with ADHD.

PubMed

Morein-Zamir, Sharon; Hommersen, Paul; Johnston, Charlotte; Kingstone, Alan

2008-11-01

Fifteen children with ADHD aged 8 to 12 years and age and gender matched controls performed two different stopping tasks to examine response performance and inhibition and their respective moment-to-moment variability. One task was the well-established stop-signal task, while the other was a novel tracking task where the children tracked a spaceship on the screen until an alarm indicated they should stop. Although performance was discrete in the stop signal task and continuous in the tracking task, in both tasks latencies to the stop signal were significantly slowed in children with ADHD. Go performance and variability did not significantly differ between ADHD and control children in either task. Importantly, stopping latency in the novel spaceship tracking task also was more variable in children with ADHD. As stopping variability cannot be measured using the standard stop signal task, the new task offers compelling support for the heretofore untested prediction that stopping is both slowed and more variable in children with ADHD. The results support a response inhibition impairment in ADHD, whilst limiting the extent of an intra-trial variability deficit.

The Galileo scan platform pointing control system - A modern control theoretic viewpoint

NASA Technical Reports Server (NTRS)

Sevaston, G. E.; Macala, G. A.; Man, G. K.

1985-01-01

The current Galileo scan platform pointing control system (SPPCS) is described, and ways in which modern control concepts could serve to enhance it are considered. Of particular interest are: the multi-variable design model and overall control system architecture, command input filtering, feedback compensator and command input design, stability robustness constraint for both continuous time control systems and for sampled data control systems, and digital implementation of the control system. The proposed approach leads to the design of a system that is similar to current Galileo SPPCS configuration, but promises to be more systematic.

Buckling Analysis of Anisotropic Curved Panels and Shells with Variable Curvature

NASA Technical Reports Server (NTRS)

Jaunky, Navin; Knight, Norman F., Jr.; Ambur, Damodar R.

1998-01-01

A buckling formulation for anisotropic curved panels with variable curvature is presented in this paper. The variable curvature panel is assumed to consists of two or more panels of constant but different curvatures. Bezier functions are used as Ritz functions Displacement (C(sup 0)), and slope (C(sup 1)) continuities between segments are imposed by manipulation of the Bezier control points. A first-order shear-deformation theory is used in the buckling formulation. Results obtained from the present formulation are compared with those from finite element simulations and are found to be in good agreement.

Pacific Decadal Variability and Central Pacific Warming El Niño in a Changing Climate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di Lorenzo, Emanuele

This research aimed at understanding the dynamics controlling decadal variability in the Pacific Ocean and its interactions with global-scale climate change. The first goal was to assess how the dynamics and statistics of the El Niño Southern Oscillation and the modes of Pacific decadal variability are represented in global climate models used in the IPCC. The second goal was to quantify how decadal dynamics are projected to change under continued greenhouse forcing, and determine their significance in the context of paleo-proxy reconstruction of long-term climate.

Comparison of methods for the analysis of relatively simple mediation models.

PubMed

Rijnhart, Judith J M; Twisk, Jos W R; Chinapaw, Mai J M; de Boer, Michiel R; Heymans, Martijn W

2017-09-01

Statistical mediation analysis is an often used method in trials, to unravel the pathways underlying the effect of an intervention on a particular outcome variable. Throughout the years, several methods have been proposed, such as ordinary least square (OLS) regression, structural equation modeling (SEM), and the potential outcomes framework. Most applied researchers do not know that these methods are mathematically equivalent when applied to mediation models with a continuous mediator and outcome variable. Therefore, the aim of this paper was to demonstrate the similarities between OLS regression, SEM, and the potential outcomes framework in three mediation models: 1) a crude model, 2) a confounder-adjusted model, and 3) a model with an interaction term for exposure-mediator interaction. Secondary data analysis of a randomized controlled trial that included 546 schoolchildren. In our data example, the mediator and outcome variable were both continuous. We compared the estimates of the total, direct and indirect effects, proportion mediated, and 95% confidence intervals (CIs) for the indirect effect across OLS regression, SEM, and the potential outcomes framework. OLS regression, SEM, and the potential outcomes framework yielded the same effect estimates in the crude mediation model, the confounder-adjusted mediation model, and the mediation model with an interaction term for exposure-mediator interaction. Since OLS regression, SEM, and the potential outcomes framework yield the same results in three mediation models with a continuous mediator and outcome variable, researchers can continue using the method that is most convenient to them.

Full-Authority Fault-Tolerant Electronic Engine Control System for Variable Cycle Engines.

DTIC Science & Technology

1982-04-01

single internally self-checked VLSI micro - processor . The selected configuration is an externally checked pair of com- mercially available...Electronic Engine Control FPMH Failures per Million Hours FTMP Fault Tolerant Multi- Processor FTSC Fault Tolerant Spaceborn Computer GRAMP Generalized...Removal * MTBR Mean Time Between Repair MTTF Mean Time to Failure xiii List of Abbreviations (continued) - NH High Pressure Rotor Speed O&S Operating

Sample size calculations for case-control studies

Cancer.gov

This R package can be used to calculate the required samples size for unconditional multivariate analyses of unmatched case-control studies. The sample sizes are for a scalar exposure effect, such as binary, ordinal or continuous exposures. The sample sizes can also be computed for scalar interaction effects. The analyses account for the effects of potential confounder variables that are also included in the multivariate logistic model.

Manipulating perceptual parameters in a continuous performance task.

PubMed

Shalev, Nir; Humphreys, Glyn; Demeyere, Nele

2018-02-01

Sustained attention (SA) is among the most studied faculties of human cognition, and thought to be crucial for many aspects of behavior. Measuring SA often relies on performance on a continuous, low-demanding task. Such continuous performance tasks (CPTs) have many variations, and sustained attention is typically estimated based on variability in reaction times. While relying on reaction times may be useful in some cases, it can pose a challenge when working with clinical populations. To increase interpersonal variability in task parameters that do not rely on speed, researchers have increased demands for memory and response inhibition. These approaches, however, may be confounded when used to assess populations that suffer from multiple cognitive deficits. In the current study, we propose a new approach for increasing task variability by increasing the attentional demands. In order to do so, we created a new variation of a CPT - a masked version, where inattention is more likely to cause misidentifying a target. After establishing that masking indeed decreases target detection, we further investigated which task parameter may influence response biases. To do so, we contrasted two versions of the CPT with different target/distractor ratio. We then established how perceptual parameters can be controlled independently in a CPT. Following the experimental manipulations, we tested the MCCPT with aging controls and chronic stroke patients to assure the task can be used with target populations. The results confirm the MCCPT as a task providing high sensitivity without relying on reaction speed, and feasible for patients.

Clinical Use of Continuous Glucose Monitoring in Adults with Type 1 Diabetes.

PubMed

Slattery, David; Choudhary, Pratik

2017-05-01

With the emphasis on intensive management of type 1 diabetes, data from studies support frequent monitoring of glucose levels to improve glycemic control and reduce glucose variability, which can be related to an increase in macro and microvascular complications. However, few perform capillary blood glucose that frequently. There are currently two available alternatives that this review will discuss, continuous glucose monitoring (CGM) and flash glucose monitoring. CGM has become an important diagnostic and therapeutic option in optimizing diabetes management. CGM systems are now more accurate, smaller, and easier to use compared to original models. Randomized controlled trials (RCTs) have demonstrated that CGM can improve Hemoglobin A1c (HbA1C) and reduce glucose variability in both continuous subcutaneous insulin infusion and multiple daily injection users. When used in an automated "insulin-suspend" system, reduced frequency of hypoglycemia and shorter time spent in hypoglycemic range have been demonstrated. Despite the potential benefits CGM has to offer in clinical practice, concerns exist on the accuracy of these devices and patient compliance with therapy, which may prevent the true clinical benefit of CGM being achieved, as observed in RCTs. Flash glucose monitoring systems FreeStyle ® Libre™ (Abbott Diabetes Care, Alameda, CA) are as accurate as many CGM systems available and have the added benefit of being factory calibrated. Studies have shown that flash glucose monitoring systems are very well tolerated by patients and effectively reduce glucose variability, increasing time in range.

Control system for a hybrid powertrain system

DOEpatents

Naqvi, Ali K.; Demirovic, Besim; Gupta, Pinaki; Kaminsky, Lawrence A.

2014-09-09

A vehicle includes a powertrain with an engine, first and second torque machines, and a hybrid transmission. A method for operating the vehicle includes operating the engine in an unfueled state, releasing an off-going clutch which when engaged effects operation of the hybrid transmission in a first continuously variable mode, and applying a friction braking torque to a wheel of the vehicle to compensate for an increase in an output torque of the hybrid transmission resulting from releasing the off-going clutch. Subsequent to releasing the off-going clutch, an oncoming clutch which when engaged effects operation of the hybrid transmission in a second continuously variable mode is synchronized. Subsequent to synchronization of the oncoming clutch, the oncoming clutch is engaged.

Dollars for lives: the effect of highway capital investments on traffic fatalities.

PubMed

Nguyen-Hoang, Phuong; Yeung, Ryan

2014-12-01

This study examines the effect of highway capital investments on highway fatalities. We used state-level data from the 48 contiguous states in the United States from 1968 through 2010 to estimate the effects on highway fatalities of capital expenditures and highway capital stock. We estimated these effects by controlling for a set of control variables together with state and year dummy variables and state-specific linear time trends. We found that capital expenditures and capital stock had significant and negative effects on highway fatalities. States faced with declines in gas tax revenues have already cut back drastically on spending on roads including on maintenance and capital outlay. If this trend continues, it may undermine traffic safety. While states and local governments are currently fiscally strained, it is important for them to continue investments in roadways to enhance traffic safety and, more significantly, to save lives. Copyright © 2014 National Safety Council and Elsevier Ltd. All rights reserved.

Power Quality Control and Design of Power Converter for Variable-Speed Wind Energy Conversion System with Permanent-Magnet Synchronous Generator

PubMed Central

Oğuz, Yüksel; Güney, İrfan; Çalık, Hüseyin

2013-01-01

The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%. PMID:24453905

Power quality control and design of power converter for variable-speed wind energy conversion system with permanent-magnet synchronous generator.

PubMed

Oğuz, Yüksel; Güney, İrfan; Çalık, Hüseyin

2013-01-01

The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%.

Control Law Design for Propofol Infusion to Regulate Depth of Hypnosis: A Nonlinear Control Strategy

PubMed Central

Khaqan, Ali; Bilal, Muhammad; Ilyas, Muhammad; Ijaz, Bilal; Ali Riaz, Raja

2016-01-01

Maintaining the depth of hypnosis (DOH) during surgery is one of the major objectives of anesthesia infusion system. Continuous administration of Propofol infusion during surgical procedures is essential but increases the undue load of an anesthetist in operating room working in a multitasking setup. Manual and target controlled infusion (TCI) systems are not good at handling instabilities like blood pressure changes and heart rate variability arising due to interpatient variability. Patient safety, large interindividual variability, and less postoperative effects are the main factors to motivate automation in anesthesia. The idea of automated system for Propofol infusion excites the control engineers to come up with a more sophisticated and safe system that handles optimum delivery of drug during surgery and avoids postoperative effects. In contrast to most of the investigations with linear control strategies, the originality of this research work lies in employing a nonlinear control technique, backstepping, to track the desired hypnosis level of patients during surgery. This effort is envisioned to unleash the true capabilities of this nonlinear control technique for anesthesia systems used today in biomedical field. The working of the designed controller is studied on the real dataset of five patients undergoing surgery. The controller tracks the desired hypnosis level within the acceptable range for surgery. PMID:27293475

Control Law Design for Propofol Infusion to Regulate Depth of Hypnosis: A Nonlinear Control Strategy.

PubMed

Khaqan, Ali; Bilal, Muhammad; Ilyas, Muhammad; Ijaz, Bilal; Ali Riaz, Raja

2015-01-01

Maintaining the depth of hypnosis (DOH) during surgery is one of the major objectives of anesthesia infusion system. Continuous administration of Propofol infusion during surgical procedures is essential but increases the undue load of an anesthetist in operating room working in a multitasking setup. Manual and target controlled infusion (TCI) systems are not good at handling instabilities like blood pressure changes and heart rate variability arising due to interpatient variability. Patient safety, large interindividual variability, and less postoperative effects are the main factors to motivate automation in anesthesia. The idea of automated system for Propofol infusion excites the control engineers to come up with a more sophisticated and safe system that handles optimum delivery of drug during surgery and avoids postoperative effects. In contrast to most of the investigations with linear control strategies, the originality of this research work lies in employing a nonlinear control technique, backstepping, to track the desired hypnosis level of patients during surgery. This effort is envisioned to unleash the true capabilities of this nonlinear control technique for anesthesia systems used today in biomedical field. The working of the designed controller is studied on the real dataset of five patients undergoing surgery. The controller tracks the desired hypnosis level within the acceptable range for surgery.

Comprehensive assessment of variables affecting metabolic control in patients with type 2 diabetes mellitus in Jordan.

PubMed

Qteishat, Rola Reyad; Ghananim, Abdel Rahman Al

2016-01-01

The aim of the study was to identify variables affecting metabolic control among diabetic patients treated at diabetes and endocrine clinic in Jordan. A total of 200 patients were studied by using a cross sectional study design. Data were collected from patients' medical records, glycemic control tests and prestructured questionnaires about variables that were potentially important based on previous researches and clinical judgment: Adherence evaluation, Patients' knowledge about drug therapy and non-pharmacological therapy, Anxiety and depression, Beliefs about diabetes treatment (benefits and barriers of treatment), Knowledge about treatment goals, Knowledge about diabetes, Self efficacy, and Social support. The mean (±SD) age was 53.5 (±10.38) years and mean HbA1c was 8.4 (±1.95). In the multivariate analysis, education level, and self efficacy found to have significantly independent association with metabolic control (P<0.03). Adequate knowledge and high self efficacy was significant in patients with good metabolic control. Emphasizing the importance of continuous educational programs and improving the self efficacy as well, could warrant achieving good metabolic control. Copyright © 2015 Diabetes India. Published by Elsevier Ltd. All rights reserved.

Optimal control of a hybrid rhythmic-discrete task: the bouncing ball revisited.

PubMed

Ronsse, Renaud; Wei, Kunlin; Sternad, Dagmar

2010-05-01

Rhythmically bouncing a ball with a racket is a hybrid task that combines continuous rhythmic actuation of the racket with the control of discrete impact events between racket and ball. This study presents experimental data and a two-layered modeling framework that explicitly addresses the hybrid nature of control: a first discrete layer calculates the state to reach at impact and the second continuous layer smoothly drives the racket to this desired state, based on optimality principles. The testbed for this hybrid model is task performance at a range of increasingly slower tempos. When slowing the rhythm of the bouncing actions, the continuous cycles become separated into a sequence of discrete movements interspersed by dwell times and directed to achieve the desired impact. Analyses of human performance show increasing variability of performance measures with slower tempi, associated with a change in racket trajectories from approximately sinusoidal to less symmetrical velocity profiles. Matching results of model simulations give support to a hybrid control model based on optimality, and therefore suggest that optimality principles are applicable to the sensorimotor control of complex movements such as ball bouncing.

Micro-Etched Platforms for Thermal Inactivation of Bacillus Anthracis and Bacillus Thuringiensis Spores

DTIC Science & Technology

2008-03-01

slips was first coated with a detergent wash. Commercially available Ivory soap shavings were diluted with sterile Millipore® water in a...environments. This removed controllable variability between the Bacillus species and increased the confidence in continued use of such surrogacy

Virtual Constraint Control of a Powered Prosthetic Leg: From Simulation to Experiments with Transfemoral Amputees.

PubMed

Gregg, Robert D; Lenzi, Tommaso; Hargrove, Levi J; Sensinger, Jonathon W

2014-12-01

Recent powered (or robotic) prosthetic legs independently control different joints and time periods of the gait cycle, resulting in control parameters and switching rules that can be difficult to tune by clinicians. This challenge might be addressed by a unifying control model used by recent bipedal robots, in which virtual constraints define joint patterns as functions of a monotonic variable that continuously represents the gait cycle phase. In the first application of virtual constraints to amputee locomotion, this paper derives exact and approximate control laws for a partial feedback linearization to enforce virtual constraints on a prosthetic leg. We then encode a human-inspired invariance property called effective shape into virtual constraints for the stance period. After simulating the robustness of the partial feedback linearization to clinically meaningful conditions, we experimentally implement this control strategy on a powered transfemoral leg. We report the results of three amputee subjects walking overground and at variable cadences on a treadmill, demonstrating the clinical viability of this novel control approach.

Virtual Constraint Control of a Powered Prosthetic Leg: From Simulation to Experiments with Transfemoral Amputees

PubMed Central

Lenzi, Tommaso; Hargrove, Levi J.; Sensinger, Jonathon W.

2014-01-01

Recent powered (or robotic) prosthetic legs independently control different joints and time periods of the gait cycle, resulting in control parameters and switching rules that can be difficult to tune by clinicians. This challenge might be addressed by a unifying control model used by recent bipedal robots, in which virtual constraints define joint patterns as functions of a monotonic variable that continuously represents the gait cycle phase. In the first application of virtual constraints to amputee locomotion, this paper derives exact and approximate control laws for a partial feedback linearization to enforce virtual constraints on a prosthetic leg. We then encode a human-inspired invariance property called effective shape into virtual constraints for the stance period. After simulating the robustness of the partial feedback linearization to clinically meaningful conditions, we experimentally implement this control strategy on a powered transfemoral leg. We report the results of three amputee subjects walking overground and at variable cadences on a treadmill, demonstrating the clinical viability of this novel control approach. PMID:25558185

Risk-Sensitivity in Sensorimotor Control

PubMed Central

Braun, Daniel A.; Nagengast, Arne J.; Wolpert, Daniel M.

2011-01-01

Recent advances in theoretical neuroscience suggest that motor control can be considered as a continuous decision-making process in which uncertainty plays a key role. Decision-makers can be risk-sensitive with respect to this uncertainty in that they may not only consider the average payoff of an outcome, but also consider the variability of the payoffs. Although such risk-sensitivity is a well-established phenomenon in psychology and economics, it has been much less studied in motor control. In fact, leading theories of motor control, such as optimal feedback control, assume that motor behaviors can be explained as the optimization of a given expected payoff or cost. Here we review evidence that humans exhibit risk-sensitivity in their motor behaviors, thereby demonstrating sensitivity to the variability of “motor costs.” Furthermore, we discuss how risk-sensitivity can be incorporated into optimal feedback control models of motor control. We conclude that risk-sensitivity is an important concept in understanding individual motor behavior under uncertainty. PMID:21283556

Continuous-variable quantum homomorphic signature

NASA Astrophysics Data System (ADS)

Li, Ke; Shang, Tao; Liu, Jian-wei

2017-10-01

Quantum cryptography is believed to be unconditionally secure because its security is ensured by physical laws rather than computational complexity. According to spectrum characteristic, quantum information can be classified into two categories, namely discrete variables and continuous variables. Continuous-variable quantum protocols have gained much attention for their ability to transmit more information with lower cost. To verify the identities of different data sources in a quantum network, we propose a continuous-variable quantum homomorphic signature scheme. It is based on continuous-variable entanglement swapping and provides additive and subtractive homomorphism. Security analysis shows the proposed scheme is secure against replay, forgery and repudiation. Even under nonideal conditions, it supports effective verification within a certain verification threshold.

Real-time control systems: feedback, scheduling and robustness

NASA Astrophysics Data System (ADS)

Simon, Daniel; Seuret, Alexandre; Sename, Olivier

2017-08-01

The efficient control of real-time distributed systems, where continuous components are governed through digital devices and communication networks, needs a careful examination of the constraints arising from the different involved domains inside co-design approaches. Thanks to the robustness of feedback control, both new control methodologies and slackened real-time scheduling schemes are proposed beyond the frontiers between these traditionally separated fields. A methodology to design robust aperiodic controllers is provided, where the sampling interval is considered as a control variable of the system. Promising experimental results are provided to show the feasibility and robustness of the approach.

Effect of progestin vs. combined oral contraceptive pills on lactation: A double-blind randomized controlled trial

PubMed Central

Espey, Eve; Ogburn, Tony; Leeman, Larry; Singh, Rameet; Schrader, Ronald

2013-01-01

Objective To estimate the effect of progestin-only vs. combined hormonal contraceptive pills on rates of breastfeeding continuation in postpartum women. Secondary outcomes include infant growth parameters, contraceptive method continuation and patient satisfaction with breastfeeding and contraceptive method. Methods In this randomized controlled trial, postpartum breastfeeding women who desired oral contraceptives were assigned to progestin-only vs. combined hormonal contraceptive pills. At two and eight weeks postpartum, participants completed in-person questionnaires that assessed breastfeeding continuation and contraceptive use. Infant growth parameters including weight, length and head circumference were assessed at eight weeks postpartum. Telephone questionnaires assessing breastfeeding, contraceptive continuation and satisfaction were completed at 3-7 weeks and 4 and 6 months. Breastfeeding continuation was compared between groups using Cox proportional hazards regression. Differences in baseline demographic characteristics and in variables between the two intervention groups were compared using chi-square tests, Fisher’s Exact test, or two-sample t-tests as appropriate. Results Breastfeeding continuation rates, contraceptive continuation, and infant growth parameters did not differ between users of progestin-only and combined hormonal contraceptive pills. Infant formula supplementation and maternal perception of inadequate milk supply were associated with decreased rates of breastfeeding in both groups. Conclusions Choice of combined or progestin-only birth control pills administered two weeks postpartum did not adversely affect breastfeeding continuation. PMID:22143258

World Ocean Database and the Global Temperature and Salinity Profile Program Database: Synthesis of historical and near real-time ocean profile data

NASA Astrophysics Data System (ADS)

Boyer, T.; Sun, L.; Locarnini, R. A.; Mishonov, A. V.; Hall, N.; Ouellet, M.

2016-02-01

The World Ocean Database (WOD) contains systematically quality controlled historical and recent ocean profile data (temperature, salinity, oxygen, nutrients, carbon cycle variables, biological variables) ranging from Captain Cooks second voyage (1773) to this year's Argo floats. The US National Centers for Environmental Information (NCEI) also hosts the Global Temperature and Salinity Profile Program (GTSPP) Continuously Managed Database (CMD) which provides quality controlled near-real time ocean profile data and higher level quality controlled temperature and salinity profiles from 1990 to present. Both databases are used extensively for ocean and climate studies. Synchronization of these two databases will allow easier access and use of comprehensive regional and global ocean profile data sets for ocean and climate studies. Synchronizing consists of two distinct phases: 1) a retrospective comparison of data in WOD and GTSPP to ensure that the most comprehensive and highest quality data set is available to researchers without the need to individually combine and contrast the two datasets and 2) web services to allow the constantly accruing near-real time data in the GTSPP CMD and the continuous addition and quality control of historical data in WOD to be made available to researchers together, seamlessly.

Does glycemic variability impact mood and quality of life?

PubMed

Penckofer, Sue; Quinn, Lauretta; Byrn, Mary; Ferrans, Carol; Miller, Michael; Strange, Poul

2012-04-01

Diabetes is a chronic condition that significantly impacts quality of life. Poor glycemic control is associated with more diabetes complications, depression, and worse quality of life. The impact of glycemic variability on mood and quality of life has not been studied. A descriptive exploratory design was used. Twenty-three women with type 2 diabetes wore a continuous glucose monitoring system for 72 h and completed a series of questionnaires. Measurements included (1) glycemic control shown by glycated hemoglobin and 24-h mean glucose, (2) glycemic variability shown by 24-h SD of the glucose readings, continuous overall net glycemic action (CONGA), and Fourier statistical models to generate smoothed curves to assess rate of change defined as "energy," and (3) mood (depression, anxiety, anger) and quality of life by questionnaires. Women with diabetes and co-morbid depression had higher anxiety, more anger, and lower quality of life than those without depression. Certain glycemic variability measures were associated with mood and quality of life. The 24-h SD of the glucose readings and the CONGA measures were significantly associated with health-related quality of life after adjusting for age and weight. Fourier models indicated that certain energy components were significantly associated with depression, trait anxiety, and overall quality of life. Finally, subjects with higher trait anxiety tended to have steeper glucose excursions. Data suggest that greater glycemic variability may be associated with lower quality of life and negative moods. Implications include replication of the study in a larger sample for the assessment of blood glucose fluctuations as they impact mood and quality of life.

Software control program for 25 kW breadboard testing. [spacecraft power supplies; high voltage batteries

NASA Technical Reports Server (NTRS)

Pajak, J. A.

1981-01-01

A data acquisition software program developed to operate in conjunction with the automated control system of the 25 kW PM Electric Power System Breadboard Test facility is described. The proram provides limited interactive control of the breadboard test while acquiring data and monitoring parameters, allowing unattended continuous operation. The breadboard test facility has two positions for operating separate configurations. The main variable in each test setup is the high voltage Ni-Cd battery.

Evolving fuzzy rules in a learning classifier system

NASA Technical Reports Server (NTRS)

Valenzuela-Rendon, Manuel

1993-01-01

The fuzzy classifier system (FCS) combines the ideas of fuzzy logic controllers (FLC's) and learning classifier systems (LCS's). It brings together the expressive powers of fuzzy logic as it has been applied in fuzzy controllers to express relations between continuous variables, and the ability of LCS's to evolve co-adapted sets of rules. The goal of the FCS is to develop a rule-based system capable of learning in a reinforcement regime, and that can potentially be used for process control.

A progress report on seismic model studies

USGS Publications Warehouse

Healy, J.H.; Mangan, G.B.

1963-01-01

The value of seismic-model studies as an aid to understanding wave propagation in the Earth's crust was recognized by early investigators (Tatel and Tuve, 1955). Preliminary model results were very promising, but progress in model seismology has been restricted by two problems: (1) difficulties in the development of models with continuously variable velocity-depth functions, and (2) difficulties in the construction of models of adequate size to provide a meaningful wave-length to layer-thickness ratio. The problem of a continuously variable velocity-depth function has been partly solved by a technique using two-dimensional plate models constructed by laminating plastic to aluminum, so that the ratio of plastic to aluminum controls the velocity-depth function (Healy and Press, 1960). These techniques provide a continuously variable velocity-depth function, but it is not possible to construct such models large enough to study short-period wave propagation in the crust. This report describes improvements in our ability to machine large models. Two types of models are being used: one is a cylindrical aluminum tube machined on a lathe, and the other is a large plate machined on a precision planer. Both of these modeling techniques give promising results and are a significant improvement over earlier efforts.

Placebo cessation in binge eating disorder: effect on anthropometric, cardiovascular, and metabolic variables.

PubMed

Blom, Thomas J; Guerdjikova, Anna I; Mori, Nicole; Casuto, Leah S; McElroy, Susan L

2015-01-01

The aim of this study was to evaluate the effects of cessation of binge eating in response to placebo treatment in binge eating disorder (BED) on anthropometric, cardiovascular, and metabolic variables. We pooled participant-level data from 10 randomized, double-blind, placebo-controlled trials of medication for BED. We then compared patients who stopped binge eating with those who did not on changes in weight, body mass index (BMI), systolic and diastolic blood pressure, pulse, and fasting lipids and glucose. Of 234 participants receiving placebo, 60 (26%) attained cessation from binge eating. Patients attaining cessation showed modestly decreased diastolic blood pressure compared with patients who continued to binge eat. Weight and BMI remained stable in patients who stopped binge eating, but increased somewhat in those who continued to binge eat. Patients who stopped binge eating with placebo had greater reductions in diastolic blood pressure and gained less weight than patients who continued to binge eat. Self-report of eating pathology in BED may predict physiologic variables. Copyright © 2014 John Wiley & Sons, Ltd and Eating Disorders Association. Copyright © 2014 John Wiley & Sons, Ltd and Eating Disorders Association.

Therapeutics of diabetes mellitus: focus on insulin analogues and insulin pumps.

PubMed

Valla, Vasiliki

2010-01-01

Inadequately controlled diabetes accounts for chronic complications and increases mortality. Its therapeutic management aims in normal HbA1C, prandial and postprandial glucose levels. This review discusses diabetes management focusing on the latest insulin analogues, alternative insulin delivery systems and the artificial pancreas. Intensive insulin therapy with multiple daily injections (MDI) allows better imitation of the physiological rhythm of insulin secretion. Longer-acting, basal insulin analogues provide concomitant improvements in safety, efficacy and variability of glycaemic control, followed by low risks of hypoglycaemia. Continuous subcutaneous insulin infusion (CSII) provides long-term glycaemic control especially in type 1 diabetic patients, while reducing hypoglycaemic episodes and glycaemic variability. Continuous subcutaneous glucose monitoring (CGM) systems provide information on postprandial glucose excursions and nocturnal hypo- and/or hyperglycemias. This information enhances treatment options, provides a useful tool for self-monitoring and allows safer achievement of treatment targets. In the absence of a cure-like pancreas or islets transplants, artificial "closed-loop" systems mimicking the pancreatic activity have been also developed. Individualized treatment plans for insulin initiation and administration mode are critical in achieving target glycaemic levels. Progress in these fields is expected to facilitate and improve the quality of life of diabetic patients.

An Avian Basal Ganglia-Forebrain Circuit Contributes Differentially to Syllable Versus Sequence Variability of Adult Bengalese Finch Song

PubMed Central

Hampton, Cara M.; Sakata, Jon T.; Brainard, Michael S.

2009-01-01

Behavioral variability is important for motor skill learning but continues to be present and actively regulated even in well-learned behaviors. In adult songbirds, two types of song variability can persist and are modulated by social context: variability in syllable structure and variability in syllable sequencing. The degree to which the control of both types of adult variability is shared or distinct remains unknown. The output of a basal ganglia-forebrain circuit, LMAN (the lateral magnocellular nucleus of the anterior nidopallium), has been implicated in song variability. For example, in adult zebra finches, neurons in LMAN actively control the variability of syllable structure. It is unclear, however, whether LMAN contributes to variability in adult syllable sequencing because sequence variability in adult zebra finch song is minimal. In contrast, Bengalese finches retain variability in both syllable structure and syllable sequencing into adulthood. We analyzed the effects of LMAN lesions on the variability of syllable structure and sequencing and on the social modulation of these forms of variability in adult Bengalese finches. We found that lesions of LMAN significantly reduced the variability of syllable structure but not of syllable sequencing. We also found that LMAN lesions eliminated the social modulation of the variability of syllable structure but did not detect significant effects on the modulation of sequence variability. These results show that LMAN contributes differentially to syllable versus sequence variability of adult song and suggest that these forms of variability are regulated by distinct neural pathways. PMID:19357331

Advanced supersonic propulsion study, phase 2. [propulsion system performance, design analysis and technology assessment

NASA Technical Reports Server (NTRS)

Howlett, R. A.

1975-01-01

A continuation of the NASA/P and WA study to evaluate various types of propulsion systems for advanced commercial supersonic transports has resulted in the identification of two very promising engine concepts. They are the Variable Stream Control Engine which provides independent temperature and velocity control for two coannular exhaust streams, and a derivative of this engine, a Variable Cycle Engine that employs a rear flow-inverter valve to vary the bypass ratio of the cycle. Both concepts are based on advanced engine technology and have the potential for significant improvements in jet noise, exhaust emissions and economic characteristics relative to current technology supersonic engines. Extensive research and technology programs are required in several critical areas that are unique to these supersonic Variable Cycle Engines to realize these potential improvements. Parametric cycle and integration studies of conventional and Variable Cycle Engines are reviewed, features of the two most promising engine concepts are described, and critical technology requirements and required programs are summarized.

Numerical Aircraft Design Using 3-D Transonic Analysis with Optimization. Volume I. Executive Summary.

DTIC Science & Technology

1981-08-01

spanl]der designs with thick wings, and winglets for transport-category aircraft; and, (2) swept forward wings, variable camber wings with direct...lift control, canards, and blended -wing concepts for fighters. Because efficient transonic performance continues to be an important design requirement

ENVIRONMENTAL VARIABLES CONTROLLING NITRIC OXIDE EMISSIONS FROM AGRICULTURAL SOILS IN THE SOUTHEAST UNITED STATES

EPA Science Inventory

Fluxes of nitric oxide (NO) were measured during the summer of 1994 (12 July to 11 August) in the Upper Coastal Plain of North Carolina in a continuing effort to characterize NO emissions from intensively managed agricultural soils in the southeastern United States. Previous work...

Evaluating variable rate fungicide applications for control of Sclerotinia

USDA-ARS?s Scientific Manuscript database

Oklahoma peanut growers continue to try to increase yields and reduce input costs. Perhaps the largest input in a peanut crop is fungicide applications. This is especially true for areas in the state that have high disease pressure from Sclerotinia. On average, a single fungicide application cost...

Vibration Control in Rotating Machinery Using Variable Dynamic Stiffness Squeeze-Films. Volume 1.

DTIC Science & Technology

1986-03-01

in Gunter’s work (13). The dynamics of a simple single mass rotor rigid shaft with squeeze film supported rolling element bearings was analysed using... Dynamics of a Rigid Rotor Supprted on Squeeze Film Bearings. Inst Mech Engrs Conf on Vibrations of Rotating Systems 1972, pp 213- 229. 23. Mohan, S., Hahn, E...Continue on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP Bearing, Squeeze Film, Vibration, Rotors 19. ABSTRACT (Continue on

A statistical model for interpreting computerized dynamic posturography data

NASA Technical Reports Server (NTRS)

Feiveson, Alan H.; Metter, E. Jeffrey; Paloski, William H.

2002-01-01

Computerized dynamic posturography (CDP) is widely used for assessment of altered balance control. CDP trials are quantified using the equilibrium score (ES), which ranges from zero to 100, as a decreasing function of peak sway angle. The problem of how best to model and analyze ESs from a controlled study is considered. The ES often exhibits a skewed distribution in repeated trials, which can lead to incorrect inference when applying standard regression or analysis of variance models. Furthermore, CDP trials are terminated when a patient loses balance. In these situations, the ES is not observable, but is assigned the lowest possible score--zero. As a result, the response variable has a mixed discrete-continuous distribution, further compromising inference obtained by standard statistical methods. Here, we develop alternative methodology for analyzing ESs under a stochastic model extending the ES to a continuous latent random variable that always exists, but is unobserved in the event of a fall. Loss of balance occurs conditionally, with probability depending on the realized latent ES. After fitting the model by a form of quasi-maximum-likelihood, one may perform statistical inference to assess the effects of explanatory variables. An example is provided, using data from the NIH/NIA Baltimore Longitudinal Study on Aging.

Quadratic constrained mixed discrete optimization with an adiabatic quantum optimizer

NASA Astrophysics Data System (ADS)

Chandra, Rishabh; Jacobson, N. Tobias; Moussa, Jonathan E.; Frankel, Steven H.; Kais, Sabre

2014-07-01

We extend the family of problems that may be implemented on an adiabatic quantum optimizer (AQO). When a quadratic optimization problem has at least one set of discrete controls and the constraints are linear, we call this a quadratic constrained mixed discrete optimization (QCMDO) problem. QCMDO problems are NP-hard, and no efficient classical algorithm for their solution is known. Included in the class of QCMDO problems are combinatorial optimization problems constrained by a linear partial differential equation (PDE) or system of linear PDEs. An essential complication commonly encountered in solving this type of problem is that the linear constraint may introduce many intermediate continuous variables into the optimization while the computational cost grows exponentially with problem size. We resolve this difficulty by developing a constructive mapping from QCMDO to quadratic unconstrained binary optimization (QUBO) such that the size of the QUBO problem depends only on the number of discrete control variables. With a suitable embedding, taking into account the physical constraints of the realizable coupling graph, the resulting QUBO problem can be implemented on an existing AQO. The mapping itself is efficient, scaling cubically with the number of continuous variables in the general case and linearly in the PDE case if an efficient preconditioner is available.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crowder, Stephen V.

This document outlines a statistical framework for establishing a shelf-life program for components whose performance is measured by the value of a continuous variable such as voltage or function time. The approach applies to both single measurement devices and repeated measurement devices, although additional process control charts may be useful in the case of repeated measurements. The approach is to choose a sample size that protects the margin associated with a particular variable over the life of the component. Deviations from expected performance of the measured variable are detected prior to the complete loss of margin. This ensures the reliabilitymore » of the component over its lifetime.« less

Preliminary Experiments with a Unified Controller for a Powered Knee-Ankle Prosthetic Leg Across Walking Speeds

PubMed Central

Villarreal, Dario J.; Gregg, Robert D.

2016-01-01

This paper presents the experimental validation of a novel control strategy that unifies the entire gait cycle of a powered knee-ankle prosthetic leg without the need to switch between controllers for different periods of gait. Current control methods divide the gait cycle into several sequential periods each with independent controllers, resulting in many patient-specific control parameters and switching rules that must be tuned for a specific walking speed. The single controller presented is speed-invariant with a minimal number of control parameters to be tuned. A single, periodic virtual constraint is derived that exactly characterizes the desired actuated joint motion as a function of a mechanical phase variable across walking cycles. A single sensor was used to compute a phase variable related to the residual thigh angle’s phase plane, which was recently shown to robustly represent the phase of non-steady human gait. This phase variable allows the prosthesis to synchronize naturally with the human user for intuitive, biomimetic behavior. A custom powered knee-ankle prosthesis was designed and built to implement the control strategy and validate its performance. A human subject experiment was conducted across multiple walking speeds (1 to 3 miles/hour) in a continuous sequence with the single phase-based controller, demonstrating its adaptability to the user’s intended speed. PMID:28392969

Effect of mycoprotein on blood lipids.

PubMed

Turnbull, W H; Leeds, A R; Edwards, G D

1990-10-01

This metabolic study was designed to investigate the effects of mycoprotein on blood lipids. Mycoprotein is a food produced by continuous fermentation of Fusarium graminearum (Schwabe) on a carbohydrate substrate. Two groups of subjects with slightly raised cholesterol concentrations took part in the 3-wk study. The experimental group was fed mycoprotein in place of meat and the control diet contained meat. There was no change in plasma cholesterol in the control group but there was a 13% reduction in the mycoprotein group. Low-density lipoprotein (LDL) increased in the control group by 12% and decreased by 9% in the mycoprotein group. High-density lipoprotein (HDL) decreased by 11% in the control group but increased by 12% in the mycoprotein group. In each case the group ANOVA differences between variables were statistically significant. It is clear from these results that lipid variables are advantageously altered by mycoprotein consumption.

Noniterative computation of infimum in H(infinity) optimisation for plants with invariant zeros on the j(omega)-axis

NASA Technical Reports Server (NTRS)

Chen, B. M.; Saber, A.

1993-01-01

A simple and noniterative procedure for the computation of the exact value of the infimum in the singular H(infinity)-optimization problem is presented, as a continuation of our earlier work. Our problem formulation is general and we do not place any restrictions in the finite and infinite zero structures of the system, and the direct feedthrough terms between the control input and the controlled output variables and between the disturbance input and the measurement output variables. Our method is applicable to a class of singular H(infinity)-optimization problems for which the transfer functions from the control input to the controlled output and from the disturbance input to the measurement output satisfy certain geometric conditions. In particular, the paper extends the result of earlier work by allowing these two transfer functions to have invariant zeros on the j(omega) axis.

Introducing a new semi-active engine mount using force controlled variable stiffness

NASA Astrophysics Data System (ADS)

Azadi, Mojtaba; Behzadipour, Saeed; Faulkner, Gary

2013-05-01

This work introduces a new concept in designing semi-active engine mounts. Engine mounts are under continuous development to provide better and more cost-effective engine vibration control. Passive engine mounts do not provide satisfactory solution. Available semi-active and active mounts provide better solutions but they are more complex and expensive. The variable stiffness engine mount (VSEM) is a semi-active engine mount with a simple ON-OFF control strategy. However, unlike available semi-active engine mounts that work based on damping change, the VSEM works based on the static stiffness change by using a new fast response force controlled variable spring. The VSEM is an improved version of the vibration mount introduced by the authors in their previous work. The results showed significant performance improvements over a passive rubber mount. The VSEM also provides better vibration control than a hydromount at idle speed. Low hysteresis and the ability to be modelled by a linear model in low-frequency are the advantages of the VSEM over the vibration isolator introduced earlier and available hydromounts. These specifications facilitate the use of VSEM in the automotive industry, however, further evaluation and developments are needed for this purpose.

A prospective, randomized, controlled study comparing Gynemesh, a synthetic mesh, and Pelvicol, a biologic graft, in the surgical treatment of recurrent cystocele.

PubMed

Natale, F; La Penna, C; Padoa, A; Agostini, M; De Simone, E; Cervigni, M

2009-01-01

We compared safety and efficacy of Gynemesh PS and Pelvicol for recurrent cystocele repair. One hundred ninety patients were randomly divided into Gynemesh PS and Pelvicol groups and underwent tension-free cystocele repair. The Chi-square test was used to compare categorical variables, the paired t test for continuous parametric variables, and the Mann-Whitney test for continuous nonparametric variables. Ninety-six Gynemesh PS patients and 94 Pelvicol patients were studied. Mesh erosions occurred in 6.3% of Gynemesh PS patients. No erosions were observed in Pelvicol patients (p = 0.02). Objective cure was 71.9% for Gynemesh PS and 56.4% for Pelvicol (p = 0.06). Subjective cure was the same in both groups except for better sexuality in the Pelvicol group. At 24 months follow-up, only Gynemesh PS patients had mesh erosions. Anatomical outcome was similar in the two groups. Pelvicol gave a better impact on voiding and sexuality.

HRV analysis in local anesthesia using Continuous Wavelet Transform (CWT).

PubMed

Shafqat, K; Pal, S K; Kumari, S; Kyriacou, P A

2011-01-01

Spectral analysis of Heart Rate Variability (HRV) is used for the assessment of cardiovascular autonomic control. In this study Continuous Wavelet Transform (CWT) has been used to evaluate the effect of local anesthesia on HRV parameters in a group of fourteen patients undergoing axillary brachial plexus block. A new method which takes signal characteristics into account has been presented for the estimation of the variable boundaries associated with the low and the high frequency band of the HRV signal. The variable boundary method might be useful in cases when the power related to respiration component extends beyond the traditionally excepted range of the high frequency band (0.15-0.4 Hz). The statistical analysis (non-parametric Wilcoxon signed rank test) showed that the LF/HF ratio decreased within an hour of the application of the brachial plexus block compared to the values fifteen minutes prior to the application of the block. These changes were observed in thirteen of the fourteen patients included in this study.

A new continuous sliding mode control approach with actuator saturation for control of 2-DOF helicopter system.

PubMed

Sadala, S P; Patre, B M

2018-03-01

The 2-degree of freedom (DOF) helicopter system is a typical higher-order, multi-variable, nonlinear and strong coupled control system. The helicopter dynamics also includes parametric uncertainties and is subject to unknown external disturbances. Such complicated system requires designing a sophisticated control algorithm that can handle these difficulties. This paper presents a new robust control algorithm which is a combination of two continuous control techniques, composite nonlinear feedback (CNF) and super-twisting control (STC) methods. In the existing integral sliding mode (ISM) based CNF control law, the discontinuous term exhibits chattering which is not desirable for many practical applications. As the continuity of well known STC reduces chattering in the system, the proposed strategy is beneficial over the current ISM based CNF control law which has a discontinuous term. Two controllers with integral sliding surface are designed to control the position of the pitch and the yaw angles of the 2- DOF helicopter. The adequacy of this specific combination has been exhibited through general analysis, simulation and experimental results of 2-DOF helicopter setup. The acquired results demonstrate the good execution of the proposed controller regarding stabilization, following reference input without overshoot against actuator saturation and robustness concerning to the limited matched disturbances. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Homeostasis: Beyond Curt Richter1

PubMed Central

Woods, Stephen C.; Ramsay, Douglas S.

2007-01-01

Curt Richter introduced behavioral control into the concept of homeostasis, thereby opening entire fields of research. The prevailing dogma, and the techniques he used, conspired to lead Richter and others to interpret regulation in strict negative feedback terms. Although this point of view continues to be embraced by many contemporary biologists, we believe that prevailing sentiment favors a broader view in which organisms integrate anticipatory pre-emptive control over regulated variables whenever possible. PMID:17524521

Method for continuous control of composition and doping of pulsed laser deposited films by pressure control

DOEpatents

Lowndes, Douglas H.; McCamy, James W.

1996-01-01

A method for growing a deposit upon a substrate of semiconductor material involves the utilization of pulsed laser deposition techniques within a low-pressure gas environment. The substrate and a target of a first material are positioned within a deposition chamber and a low-pressure gas atmosphere is developed within the chamber. The substrate is then heated, and the target is irradiated, so that atoms of the target material are ablated from the remainder of the target, while atoms of the gas simultaneously are adsorbed on the substrate/film surface. The ablated atoms build up upon the substrate, together with the adsorbed gas atoms to form the thin-film deposit on the substrate. By controlling the pressure of the gas of the chamber atmosphere, the composition of the formed deposit can be controlled, and films of continuously variable composition or doping can be grown from a single target of fixed composition.

Temporal Dynamics and Persistence of Spatial Patterns: from Groundwater to Soil Moisture to Transpiration

NASA Astrophysics Data System (ADS)

Blume, T.; Hassler, S. K.; Weiler, M.

2017-12-01

Hydrological science still struggles with the fact that while we wish for spatially continuous images or movies of state variables and fluxes at the landscape scale, most of our direct measurements are point measurements. To date regional measurements resolving landscape scale patterns can only be obtained by remote sensing methods, with the common drawback that they remain near the earth surface and that temporal resolution is generally low. However, distributed monitoring networks at the landscape scale provide the opportunity for detailed and time-continuous pattern exploration. Even though measurements are spatially discontinuous, the large number of sampling points and experimental setups specifically designed for the purpose of landscape pattern investigation open up new avenues of regional hydrological analyses. The CAOS hydrological observatory in Luxembourg offers a unique setup to investigate questions of temporal stability, pattern evolution and persistence of certain states. The experimental setup consists of 45 sensor clusters. These sensor clusters cover three different geologies, two land use classes, five different landscape positions, and contrasting aspects. At each of these sensor clusters three soil moisture/soil temperature profiles, basic climate variables, sapflow, shallow groundwater, and stream water levels were measured continuously for the past 4 years. We will focus on characteristic landscape patterns of various hydrological state variables and fluxes, studying their temporal stability on the one hand and the dependence of patterns on hydrological states on the other hand (e.g. wet vs dry). This is extended to time-continuous pattern analysis based on time series of spatial rank correlation coefficients. Analyses focus on the absolute values of soil moisture, soil temperature, groundwater levels and sapflow, but also investigate the spatial pattern of the daily changes of these variables. The analysis aims at identifying hydrologic signatures of the processes or landscape characteristics acting as major controls. While groundwater, soil water and transpiration are closely linked by the water cycle, they are controlled by different processes and we expect this to be reflected in interlinked but not necessarily congruent patterns and responses.

Mutilating Data and Discarding Variance: The Dangers of Dichotomizing Continuous Variables.

ERIC Educational Resources Information Center

Kroff, Michael W.

This paper reviews issues involved in converting continuous variables to nominal variables to be used in the OVA techniques. The literature dealing with the dangers of dichotomizing continuous variables is reviewed. First, the assumptions invoked by OVA analyses are reviewed in addition to concerns regarding the loss of variance and a reduction in…

Continuous measurement of aortic dimensions in Turner syndrome: a cardiovascular magnetic resonance study.

PubMed

Subramaniam, Dhananjay Radhakrishnan; Stoddard, William A; Mortensen, Kristian H; Ringgaard, Steffen; Trolle, Christian; Gravholt, Claus H; Gutmark, Ephraim J; Mylavarapu, Goutham; Backeljauw, Philippe F; Gutmark-Little, Iris

2017-02-24

Severity of thoracic aortic disease in Turner syndrome (TS) patients is currently described through measures of aorta size and geometry at discrete locations. The objective of this study is to develop an improved measurement tool that quantifies changes in size and geometry over time, continuously along the length of the thoracic aorta. Cardiovascular magnetic resonance (CMR) scans for 15 TS patients [41 ± 9 years (mean age ± standard deviation (SD))] were acquired over a 10-year period and compared with ten healthy gender and age-matched controls. Three-dimensional aortic geometries were reconstructed, smoothed and clipped, which was followed by identification of centerlines and planes normal to the centerlines. Geometric variables, including maximum diameter and cross-sectional area, were evaluated continuously along the thoracic aorta. Distance maps were computed for TS and compared to the corresponding maps for controls, to highlight any asymmetry and dimensional differences between diseased and normal aortae. Furthermore, a registration scheme was proposed to estimate localized changes in aorta geometry between visits. The estimated maximum diameter from the continuous method was then compared with corresponding manual measurements at 7 discrete locations for each visit and for changes between visits. Manual measures at the seven positions and the corresponding continuous measurements of maximum diameter for all visits considered, correlated highly (R-value = 0.77, P < 0.01). There was good agreement between manual and continuous measurement methods for visit-to-visit changes in maximum diameter. The continuous method was less sensitive to inter-user variability [0.2 ± 2.3 mm (mean difference in diameters ± SD)] and choice of smoothing software [0.3 ± 1.3 mm]. Aortic diameters were larger in TS than controls in the ascending [TS: 13.4 ± 2.1 mm (mean distance ± SD), Controls: 12.6 ± 1 mm] and descending [TS: 10.2 ± 1.3 mm (mean distance ± SD), Controls: 9.5 ± 0.9 mm] thoracic aorta as observed from the distance maps. An automated methodology is presented that enables rapid and precise three-dimensional measurement of thoracic aortic geometry, which can serve as an improved tool to define disease severity and monitor disease progression. ClinicalTrials.gov Identifier - NCT01678274 . Registered - 08.30.2012.

Randomized trial of intermittent or continuous amnioinfusion for variable decelerations.

PubMed

Rinehart, B K; Terrone, D A; Barrow, J H; Isler, C M; Barrilleaux, P S; Roberts, W E

2000-10-01

To determine whether continuous or intermittent bolus amnioinfusion is more effective in relieving variable decelerations. Patients with repetitive variable decelerations were randomized to an intermittent bolus or continuous amnioinfusion. The intermittent bolus infusion group received boluses of 500 mL of normal saline, each over 30 minutes, with boluses repeated if variable decelerations recurred. The continuous infusion group received a bolus infusion of 500 mL of normal saline over 30 minutes and then 3 mL per minute until delivery occurred. The ability of the amnioinfusion to abolish variable decelerations was analyzed, as were maternal demographic and pregnancy outcome variables. Power analysis indicated that 64 patients would be required. Thirty-five patients were randomized to intermittent infusion and 30 to continuous infusion. There were no differences between groups in terms of maternal demographics, gestational age, delivery mode, neonatal outcome, median time to resolution of variable decelerations, or the number of times variable decelerations recurred. The median volume infused in the intermittent infusion group (500 mL) was significantly less than that in the continuous infusion group (905 mL, P =.003). Intermittent bolus amnioinfusion is as effective as continuous infusion in relieving variable decelerations in labor. Further investigation is necessary to determine whether either of these techniques is associated with increased occurrence of rare complications such as cord prolapse or uterine rupture.

An inverter/controller subsystem optimized for photovoltaic applications

NASA Technical Reports Server (NTRS)

Pickrell, R. L.; Osullivan, G.; Merrill, W. C.

1978-01-01

Conversion of solar array dc power to ac power stimulated the specification, design, and simulation testing of an inverter/controller subsystem tailored to the photovoltaic power source characteristics. Optimization of the inverter/controller design is discussed as part of an overall photovoltaic power system designed for maximum energy extraction from the solar array. The special design requirements for the inverter/ controller include: a power system controller (PSC) to control continuously the solar array operating point at the maximum power level based on variable solar insolation and cell temperatures; and an inverter designed for high efficiency at rated load and low losses at light loadings to conserve energy.

SLEEP AND MENTAL DISORDERS: A META-ANALYSIS OF POLYSOMNOGRAPHIC RESEARCH

PubMed Central

Baglioni, Chiara; Nanovska, Svetoslava; Regen, Wolfram; Spiegelhalder, Kai; Feige, Bernd; Nissen, Christoph; Reynolds, Charles F.; Riemann, Dieter

2016-01-01

Investigating sleep in mental disorders has the potential to reveal both disorder-specific and transdiagnostic psychophysiological mechanisms. This meta-analysis aimed at determining the polysomnographic (PSG) characteristics of several mental disorders. Relevant studies were searched through standard strategies. Controlled PSG studies evaluating sleep in affective, anxiety, eating, pervasive developmental, borderline and antisocial personality disorders, ADHD, and schizophrenia were included. PSG variables of sleep continuity, depth, and architecture, as well as rapid-eye movement (REM) sleep were considered. Calculations were performed with the “Comprehensive Meta-Analysis” and “R” softwares. Using random effects modeling, for each disorder and each variable, a separate meta-analysis was conducted if at least 3 studies were available for calculation of effect sizes as standardized means (Hedges’g). Sources of variability, i.e., sex, age, and mental disorders comorbidity, were evaluated in subgroup analyses. Sleep alterations were evidenced in all disorders, with the exception of ADHD and seasonal affective disorders. Sleep continuity problems were observed in most mental disorders. Sleep depth and REM pressure alterations were associated with affective, anxiety, autism and schizophrenia disorders. Comorbidity was associated with enhanced REM sleep pressure and more inhibition of sleep depth. No sleep parameter was exclusively altered in one condition; however, no two conditions shared the same PSG profile. Sleep continuity disturbances imply a transdiagnostic imbalance in the arousal system likely representing a basic dimension of mental health. Sleep depth and REM variables might play a key role in psychiatric comorbidity processes. Constellations of sleep alterations may define distinct disorders better than alterations in one single variable. PMID:27416139

Control of a Non-foodborne Outbreak of Salmonellosis: Day Care in Isolation.

ERIC Educational Resources Information Center

Chorba, Terence, L.; And Others

1987-01-01

In this study of a salmonellosis outbreak at a day care center an analysis of five variables revealed that the disease was transferred person to person or by a continuing common source. Successful preventive measures included instruction in proper handwashing and diaper changing procedures and isolation of the infected children. (VM)

Effectiveness of a stepped primary care smoking cessation intervention: cluster randomized clinical trial (ISTAPS study).

PubMed

Cabezas, Carmen; Advani, Mamta; Puente, Diana; Rodriguez-Blanco, Teresa; Martin, Carlos

2011-09-01

To evaluate the effectiveness in primary care of a stepped smoking cessation intervention based on the transtheoretical model of change. Cluster randomized trial; unit of randomization: basic care unit (family physician and nurse who care for the same group of patients); and intention-to-treat analysis. All interested basic care units (n = 176) that worked in 82 primary care centres belonging to the Spanish Preventive Services and Health Promotion Research Network in 13 regions of Spain. A total of 2,827 smokers (aged 14-85 years) who consulted a primary care centre for any reason, provided written informed consent and had valid interviews. The outcome variable was the 1-year continuous abstinence rate at the 2-year follow-up. The main variable was the study group (intervention/control). Intervention involved 6-month implementation of recommendations from a Clinical Practice Guideline which included brief motivational interviews for smokers at the precontemplation-contemplation stage, brief intervention for smokers in preparation-action who do not want help, intensive intervention with pharmacotherapy for smokers in preparation-action who want help and reinforcing intervention in the maintenance stage. Control group involved usual care. Among others, characteristics of tobacco use and motivation to quit variables were also collected. The 1-year continuous abstinence rate at the 2-year follow-up was 8.1% in the intervention group and 5.8% in the control group (P = 0.014). In the multivariate logistic regression, the odds of quitting of the intervention versus control group was 1.50 (95% confidence interval = 1.05-2.14). A stepped smoking cessation intervention based on the transtheoretical model significantly increased smoking abstinence at a 2-year follow-up among smokers visiting primary care centres. © 2011 The Authors, Addiction © 2011 Society for the Study of Addiction.

Does Glycemic Variability Impact Mood and Quality of Life?

PubMed Central

Quinn, Lauretta; Byrn, Mary; Ferrans, Carol; Miller, Michael; Strange, Poul

2012-01-01

Abstract Background Diabetes is a chronic condition that significantly impacts quality of life. Poor glycemic control is associated with more diabetes complications, depression, and worse quality of life. The impact of glycemic variability on mood and quality of life has not been studied. Methods A descriptive exploratory design was used. Twenty-three women with type 2 diabetes wore a continuous glucose monitoring system for 72 h and completed a series of questionnaires. Measurements included (1) glycemic control shown by glycated hemoglobin and 24-h mean glucose, (2) glycemic variability shown by 24-h SD of the glucose readings, continuous overall net glycemic action (CONGA), and Fourier statistical models to generate smoothed curves to assess rate of change defined as “energy,” and (3) mood (depression, anxiety, anger) and quality of life by questionnaires. Results Women with diabetes and co-morbid depression had higher anxiety, more anger, and lower quality of life than those without depression. Certain glycemic variability measures were associated with mood and quality of life. The 24-h SD of the glucose readings and the CONGA measures were significantly associated with health-related quality of life after adjusting for age and weight. Fourier models indicated that certain energy components were significantly associated with depression, trait anxiety, and overall quality of life. Finally, subjects with higher trait anxiety tended to have steeper glucose excursions. Conclusions Data suggest that greater glycemic variability may be associated with lower quality of life and negative moods. Implications include replication of the study in a larger sample for the assessment of blood glucose fluctuations as they impact mood and quality of life. PMID:22324383

Continuously-Variable Positive-Mesh Power Transmission

NASA Technical Reports Server (NTRS)

Johnson, J. L.

1982-01-01

Proposed transmission with continuously-variable speed ratio couples two mechanical trigonometric-function generators. Transmission is expected to handle higher loads than conventional variable-pulley drives; and, unlike variable pulley, positive traction through entire drive train with no reliance on friction to transmit power. Able to vary speed continuously through zero and into reverse. Possible applications in instrumentation where drive-train slippage cannot be tolerated.

Nurse Continuity and Hospital-Acquired Pressure Ulcers: A Comparative Analysis Using an Electronic Health Record "Big Data" Set.

PubMed

Stifter, Janet; Yao, Yingwei; Lodhi, Muhammad Kamran; Lopez, Karen Dunn; Khokhar, Ashfaq; Wilkie, Diana J; Keenan, Gail M

2015-01-01

Little research demonstrating the association between nurse continuity and patient outcomes exists despite an intuitive belief that continuity makes a difference in care outcomes. The aim of this study was to examine the association of nurse continuity with the prevention of hospital-acquired pressure ulcers (HAPU). A secondary use of data from the Hands on Automated Nursing Data System (HANDS) was performed for this comparative study. The HANDS is a nursing plan of care data set containing 42,403 episodes documented by 787 nurses, on nine units, in four hospitals and includes nurse staffing and patient characteristics. The HANDS data set resides in a "big data" relational database consisting of 89 tables and 747 columns of data. Via data mining, we created an analytic data set of 840 care episodes, 210 with and 630 without HAPUs, matched by nursing unit, patient age, and patient characteristics. Logistic regression analysis determined the association of nurse continuity and additional nurse-staffing variables on HAPU occurrence. Poor nurse continuity (unit mean continuity index = .21-.42 [1.0 = optimal continuity]) was noted on all nine study units. Nutrition, mobility, perfusion, hydration, and skin problems on admission, as well as patient age, were associated with HAPUs (p < .001). Controlling for patient characteristics, nurse continuity, and the interactions between nurse continuity and other nurse-staffing variables were not significantly associated with HAPU development. Patient characteristics including nutrition, mobility, and perfusion were associated with HAPUs, but nurse continuity was not. We demonstrated a high level of variation in the degree of continuity between patient episodes in the HANDS data, showing that it offers rich potential for future study of nurse continuity and its effect on patient outcomes.

Integrated controls and health monitoring for chemical transfer propulsion

NASA Technical Reports Server (NTRS)

Millis, Marc G.; Binder, Michael P.

1990-01-01

NASA is reviewing various propulsion technologies for exploring space. The requirements are examined for one enabling propulsion technology: Integrated Controls and Health Monitoring (ICHM) for Chemical Transfer Propulsion (CTP). Functional requirements for a CTP-ICHM system are proposed from tentative mission scenarios, vehicle configurations, CTP specifications, and technical feasibility. These CTP-ICHM requirements go beyond traditional reliable operation and emergency shutoff control to include: (1) enhanced mission flexibility; (2) continuously variable throttling; (3) tank-head start control; (4) automated prestart and post-shutoff engine check; (5) monitoring of space exposure degradation; and (6) product evolution flexibility. Technology development plans are also discussed.

Robust control of a parallel hybrid drivetrain with a CVT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mayer, T.; Schroeder, D.

1996-09-01

In this paper the design of a robust control system for a parallel hybrid drivetrain is presented. The drivetrain is based on a continuously variable transmission (CVT) and is therefore a highly nonlinear multiple-input-multiple-output system (MIMO-System). Input-Output-Linearization offers the possibility of linearizing and of decoupling the system. Since for example the vehicle mass varies with the load and the efficiency of the gearbox depends strongly on the actual working point, an exact linearization of the plant will mostly fail. Therefore a robust control algorithm based on sliding mode is used to control the drivetrain.

On which timescales do gas transfer velocities control North Atlantic CO2 flux variability?

NASA Astrophysics Data System (ADS)

Couldrey, Matthew; Oliver, Kevin; Yool, Andrew; Halloran, Paul; Achterberg, Eric

2016-04-01

The North Atlantic is an important basin for the global ocean's uptake of anthropogenic and natural carbon dioxide (CO2), but the mechanisms controlling this carbon flux are not fully understood. The air-sea flux of CO2, F, is the product of a gas transfer velocity, k, the air-sea CO2concentration gradient, ΔpCO2, and the temperature and salinity-dependent solubility coefficient, α. k is difficult to constrain, representing the dominant uncertainty in F on short (instantaneous to interannual) timescales. Previous work shows that in the North Atlantic, ΔpCO2and k both contribute significantly to interannual F variability, but that k is unimportant for multidecadal variability. On some timescale between interannual and multidecadal, gas transfer velocity variability and its associated uncertainty become negligible. Here, we quantify this critical timescale for the first time. Using an ocean model, we determine the importance of k, ΔpCO2and α on a range of timescales. On interannual and shorter timescales, both ΔpCO2and k are important controls on F. In contrast, pentadal to multidecadal North Atlantic flux variability is driven almost entirely by ΔpCO2; k contributes less than 25%. Finally, we explore how accurately one can estimate North Atlantic F without a knowledge of non-seasonal k variability, finding it possible for interannual and longer timescales. These findings suggest that continued efforts to better constrain gas transfer velocities are necessary to quantify interannual variability in the North Atlantic carbon sink. However, uncertainty in k variability is unlikely to limit the accuracy of estimates of longer term flux variability.

On which timescales do gas transfer velocities control North Atlantic CO2 flux variability?

NASA Astrophysics Data System (ADS)

Couldrey, Matthew P.; Oliver, Kevin I. C.; Yool, Andrew; Halloran, Paul R.; Achterberg, Eric P.

2016-05-01

The North Atlantic is an important basin for the global ocean's uptake of anthropogenic and natural carbon dioxide (CO2), but the mechanisms controlling this carbon flux are not fully understood. The air-sea flux of CO2, F, is the product of a gas transfer velocity, k, the air-sea CO2 concentration gradient, ΔpCO2, and the temperature- and salinity-dependent solubility coefficient, α. k is difficult to constrain, representing the dominant uncertainty in F on short (instantaneous to interannual) timescales. Previous work shows that in the North Atlantic, ΔpCO2 and k both contribute significantly to interannual F variability but that k is unimportant for multidecadal variability. On some timescale between interannual and multidecadal, gas transfer velocity variability and its associated uncertainty become negligible. Here we quantify this critical timescale for the first time. Using an ocean model, we determine the importance of k, ΔpCO2, and α on a range of timescales. On interannual and shorter timescales, both ΔpCO2 and k are important controls on F. In contrast, pentadal to multidecadal North Atlantic flux variability is driven almost entirely by ΔpCO2; k contributes less than 25%. Finally, we explore how accurately one can estimate North Atlantic F without a knowledge of nonseasonal k variability, finding it possible for interannual and longer timescales. These findings suggest that continued efforts to better constrain gas transfer velocities are necessary to quantify interannual variability in the North Atlantic carbon sink. However, uncertainty in k variability is unlikely to limit the accuracy of estimates of longer-term flux variability.

On which timescales do gas transfer velocities control North Atlantic CO2 flux variability?

NASA Astrophysics Data System (ADS)

Couldrey, M.; Oliver, K. I. C.; Yool, A.; Halloran, P. R.; Achterberg, E. P.

2016-02-01

The North Atlantic is an important basin for the global ocean's uptake of anthropogenic and natural carbon dioxide (CO2), but the mechanisms controlling this carbon flux are not fully understood. The air-sea flux of CO2, F, is the product of a gas transfer velocity, k, the air-sea CO2 concentration gradient, ΔpCO2, and the temperature and salinity-dependent solubility coefficient, α. k is difficult to constrain, representing the dominant uncertainty in F on short (instantaneous to interannual) timescales. Previous work shows that in the North Atlantic, ΔpCO2 and k both contribute significantly to interannual F variability, but that k is unimportant for multidecadal variability. On some timescale between interannual and multidecadal, gas transfer velocity variability and its associated uncertainty become negligible. Here, we quantify this critical timescale for the first time. Using an ocean model, we determine the importance of k, ΔpCO2 and α on a range of timescales. On interannual and shorter timescales, both ΔpCO2 and k are important controls on F. In contrast, pentadal to multidecadal North Atlantic flux variability is driven almost entirely by ΔpCO2; k contributes less than 25%. Finally, we explore how accurately one can estimate North Atlantic F without a knowledge of non-seasonal k variability, finding it possible for interannual and longer timescales. These findings suggest that continued efforts to better constrain gas transfer velocities are necessary to quantify interannual variability in the North Atlantic carbon sink. However, uncertainty in k variability is unlikely to limit the accuracy of estimates of longer term flux variability.

VARIABLE AREA CONTROL ROD FOR NUCLEAR REACTOR

DOEpatents

Huston, N.E.

1960-05-01

A control rod is described which permits continual variation of its absorbing strength uniformly along the length of the rod. The rod is fail safe and is fully inserted into the core but changes in its absorbing strength do not produce axial flux distortion. The control device comprises a sheet containing a material having a high thermal-neutron absorption cross section. A pair of shafts engage the sheet along the longitudinal axis of the shafts and gears associated with the shafts permit winding and unwinding of the sheet around the shafts.

Qubit-Programmable Operations on Quantum Light Fields

PubMed Central

Barbieri, Marco; Spagnolo, Nicolò; Ferreyrol, Franck; Blandino, Rémi; Smith, Brian J.; Tualle-Brouri, Rosa

2015-01-01

Engineering quantum operations is a crucial capability needed for developing quantum technologies and designing new fundamental physics tests. Here we propose a scheme for realising a controlled operation acting on a travelling continuous-variable quantum field, whose functioning is determined by a discrete input qubit. This opens a new avenue for exploiting advantages of both information encoding approaches. Furthermore, this approach allows for the program itself to be in a superposition of operations, and as a result it can be used within a quantum processor, where coherences must be maintained. Our study can find interest not only in general quantum state engineering and information protocols, but also details an interface between different physical platforms. Potential applications can be found in linking optical qubits to optical systems for which coupling is best described in terms of their continuous variables, such as optomechanical devices. PMID:26468614

Continuous-variable quantum key distribution in uniform fast-fading channels

NASA Astrophysics Data System (ADS)

Papanastasiou, Panagiotis; Weedbrook, Christian; Pirandola, Stefano

2018-03-01

We investigate the performance of several continuous-variable quantum key distribution protocols in the presence of uniform fading channels. These are lossy channels whose transmissivity changes according to a uniform probability distribution. We assume the worst-case scenario where an eavesdropper induces a fast-fading process, where she chooses the instantaneous transmissivity while the remote parties may only detect the mean statistical effect. We analyze coherent-state protocols in various configurations, including the one-way switching protocol in reverse reconciliation, the measurement-device-independent protocol in the symmetric configuration, and its extension to a three-party network. We show that, regardless of the advantage given to the eavesdropper (control of the fading), these protocols can still achieve high rates under realistic attacks, within reasonable values for the variance of the probability distribution associated with the fading process.

Continuous variable quantum optical simulation for time evolution of quantum harmonic oscillators

PubMed Central

Deng, Xiaowei; Hao, Shuhong; Guo, Hong; Xie, Changde; Su, Xiaolong

2016-01-01

Quantum simulation enables one to mimic the evolution of other quantum systems using a controllable quantum system. Quantum harmonic oscillator (QHO) is one of the most important model systems in quantum physics. To observe the transient dynamics of a QHO with high oscillation frequency directly is difficult. We experimentally simulate the transient behaviors of QHO in an open system during time evolution with an optical mode and a logical operation system of continuous variable quantum computation. The time evolution of an atomic ensemble in the collective spontaneous emission is analytically simulated by mapping the atomic ensemble onto a QHO. The measured fidelity, which is used for quantifying the quality of the simulation, is higher than its classical limit. The presented simulation scheme provides a new tool for studying the dynamic behaviors of QHO. PMID:26961962

Adaptive feedback synchronisation of complex dynamical network with discrete-time communications and delayed nodes

NASA Astrophysics Data System (ADS)

Wang, Tong; Ding, Yongsheng; Zhang, Lei; Hao, Kuangrong

2016-08-01

This paper considered the synchronisation of continuous complex dynamical networks with discrete-time communications and delayed nodes. The nodes in the dynamical networks act in the continuous manner, while the communications between nodes are discrete-time; that is, they communicate with others only at discrete time instants. The communication intervals in communication period can be uncertain and variable. By using a piecewise Lyapunov-Krasovskii function to govern the characteristics of the discrete communication instants, we investigate the adaptive feedback synchronisation and a criterion is derived to guarantee the existence of the desired controllers. The globally exponential synchronisation can be achieved by the controllers under the updating laws. Finally, two numerical examples including globally coupled network and nearest-neighbour coupled networks are presented to demonstrate the validity and effectiveness of the proposed control scheme.

Cardiopulmonary disease in newborns: a study in continuing medical education.

PubMed

Weinberg, A D; McNamara, D G; Christiansen, C H; Taylor, F M; Armitage, M

1979-03-01

A film emphasizing the importance of tachypnea as an early manifestation of congenital heart disease was shown to physicians and nurses at 27 hospitals as part of their regular continuing medical education activities. To evaluate the effects of the program, investigators developed a pretest-posttest design which included a nonequivalent control group. Pretest and posttest data were obtained through chart audit of referrals from subjects in experimental and control groups. Dependent variables used to test the hypothesis included the age at which infants were referred and the age at which tachypnea was noted. Analysis of the data yielded significant gain scores for the experimental group, while changes in the control group were not significant. The findings indicate that a need-oriented educational program can have a measurable impact on improving the quality of patient care.

Using statistical process control to make data-based clinical decisions.

PubMed

Pfadt, A; Wheeler, D J

1995-01-01

Applied behavior analysis is based on an investigation of variability due to interrelationships among antecedents, behavior, and consequences. This permits testable hypotheses about the causes of behavior as well as for the course of treatment to be evaluated empirically. Such information provides corrective feedback for making data-based clinical decisions. This paper considers how a different approach to the analysis of variability based on the writings of Walter Shewart and W. Edwards Deming in the area of industrial quality control helps to achieve similar objectives. Statistical process control (SPC) was developed to implement a process of continual product improvement while achieving compliance with production standards and other requirements for promoting customer satisfaction. SPC involves the use of simple statistical tools, such as histograms and control charts, as well as problem-solving techniques, such as flow charts, cause-and-effect diagrams, and Pareto charts, to implement Deming's management philosophy. These data-analytic procedures can be incorporated into a human service organization to help to achieve its stated objectives in a manner that leads to continuous improvement in the functioning of the clients who are its customers. Examples are provided to illustrate how SPC procedures can be used to analyze behavioral data. Issues related to the application of these tools for making data-based clinical decisions and for creating an organizational climate that promotes their routine use in applied settings are also considered.

Deficits in inhibitory force control in young adults with ADHD.

PubMed

Neely, Kristina A; Wang, Peiyuan; Chennavasin, Amanda P; Samimy, Shaadee; Tucker, Jacqueline; Merida, Andrea; Perez-Edgar, Koraly; Huang-Pollock, Cynthia

2017-05-01

Poor inhibitory control is a well-established cognitive correlate of adults with ADHD. However, the simple reaction time (RT) task used in a majority of studies records performance errors only via the presence or absence of a single key press. This all-or-nothing response makes it impossible to capture subtle differences in underlying processes that shape performance. Subsequently, all-or-nothing tasks may underestimate the prevalence of executive function deficits in ADHD. The current study measured inhibitory control using a standard Go/No-Go RT task and a more sensitive continuous grip force task among adults with (N=51, 22 female) and without (N=51, 29 female) ADHD. Compared to adults without ADHD, adults with ADHD made more failed inhibits in the classic Go/No-Go paradigm and produced greater and more variable force during motor inhibition. The amount of force produced on failed inhibits was a stronger predictor of ADHD-related symptoms than the number of commissions in the standard RT task. Adults with ADHD did not differ from those without ADHD on the mean force and variability of force produced in Go trials. These findings suggest that the use of a precise and continuous motor task, such as the force task used here, provides additional information about the nature of inhibitory motor control in adults with ADHD. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sleep continuity is positively correlated with sleep duration in laboratory nighttime sleep recordings

PubMed Central

Van Dongen, Hans P. A.; Natelson, Benjamin H.; Bender, Amy M.; Palombini, Luciana O.; Bittencourt, Lia; Tufik, Sergio; Ayappa, Indu; Rapoport, David M.

2017-01-01

Sleep duration varies widely across individuals and appears to be trait-like. Differences in the stability of underlying sleep processes may underlie this phenomenon. To investigate underlying mechanisms, we examined the relationship between sleep duration and sleep continuity in baseline polysomnography (PSG) recordings from three independently collected datasets: 1) 134 healthy controls (ages 37 ± 13 years) from the São Paulo Epidemiologic Sleep Study, who spent one night in a sleep laboratory, 2) 21 obstructive sleep apnea (OSA) patients who were treated with continuous positive airway pressure for at least 2 months (45 ± 12 years, respiratory disturbance index <15), who spent one night in a sleep laboratory with previous experience of multiple PSG studies, and 3) 62 healthy controls (28 ± 6 years) who, as part of larger experiments, spent 2 consecutive nights in a sleep laboratory. For each dataset, we used total sleep time (TST) to separate subjects into those with shorter sleep (S-TST) and those with longer sleep (L-TST). In all three datasets, survival curves of continuous sleep segments showed greater sleep continuity in L-TST than in S-TST. Correlation analyses with TST as a continuous variable corroborated the results; and the results also held true after controlling for age. There were no significant differences in baseline waking performance and sleepiness between S-TST and L-TST. In conclusion, in both healthy controls and treated OSA patients, sleep continuity was positively correlated with sleep duration. These findings suggest that S-TST may differ from L-TST in processes underlying sleep continuity, shedding new light on mechanisms underlying individual differences in sleep duration. PMID:28394943

A Simulation Study of Categorizing Continuous Exposure Variables Measured with Error in Autism Research: Small Changes with Large Effects.

PubMed

Heavner, Karyn; Burstyn, Igor

2015-08-24

Variation in the odds ratio (OR) resulting from selection of cutoffs for categorizing continuous variables is rarely discussed. We present results for the effect of varying cutoffs used to categorize a mismeasured exposure in a simulated population in the context of autism spectrum disorders research. Simulated cohorts were created with three distinct exposure-outcome curves and three measurement error variances for the exposure. ORs were calculated using logistic regression for 61 cutoffs (mean ± 3 standard deviations) used to dichotomize the observed exposure. ORs were calculated for five categories with a wide range for the cutoffs. For each scenario and cutoff, the OR, sensitivity, and specificity were calculated. The three exposure-outcome relationships had distinctly shaped OR (versus cutoff) curves, but increasing measurement error obscured the shape. At extreme cutoffs, there was non-monotonic oscillation in the ORs that cannot be attributed to "small numbers." Exposure misclassification following categorization of the mismeasured exposure was differential, as predicted by theory. Sensitivity was higher among cases and specificity among controls. Cutoffs chosen for categorizing continuous variables can have profound effects on study results. When measurement error is not too great, the shape of the OR curve may provide insight into the true shape of the exposure-disease relationship.

Islet Transplantation Provides Superior Glycemic Control With Less Hypoglycemia Compared With Continuous Subcutaneous Insulin Infusion or Multiple Daily Insulin Injections.

PubMed

Holmes-Walker, Deborah Jane; Gunton, Jenny E; Hawthorne, Wayne; Payk, Marlene; Anderson, Patricia; Donath, Susan; Loudovaris, Tom; Ward, Glenn M; Kay, Thomas Wh; OʼConnell, Philip J

2017-06-01

The aim was to compare efficacy of multiple daily injections (MDI), continuous subcutaneous insulin infusion (CSII) and islet transplantation to reduce hypoglycemia and glycemic variability in type 1 diabetes subjects with severe hypoglycemia. This was a within-subject, paired comparison of MDI and CSII and CSII with 12 months postislet transplantation in 10 type 1 diabetes subjects referred with severe hypoglycemia, suitable for islet transplantation. Individuals were assessed with HbA1c, Edmonton Hypoglycemia Score (HYPOscore), continuous glucose monitoring (CGM) and in 8 subjects measurements of glucose variability using standard deviation of glucose (SD glucose) from CGM and continuous overlapping net glycemic action using a 4 hour interval (CONGA4). After changing from MDI to CSII before transplantation, 10 subjects reduced median HYPOscore from 2028 to 1085 (P < 0.05) and hypoglycemia events from 24 to 8 per patient-year (P < 0.05). While HbA1c, mean glucose and median percent time hypoglycemic on CGM were unchanged with CSII, SD glucose and CONGA4 reduced significantly (P < 0.05). At 12 months posttransplant 9 of 10 were C-peptide positive, (5 insulin independent). Twelve months postislet transplantation, there were significant reductions in all baseline parameters versus CSII, respectively, HbA1c (6.4% cf 8.2%), median HYPOscore (0 cf 1085), mean glucose (7.1 cf 8.6 mmol L), SD glucose (1.7 cf 3.2 mmol/L), and CONGA4 (1.6 cf 3.0). In subjects with severe hypoglycemia suitable for islet transplantation, CSII decreased hypoglycemia frequency and glycemic variability compared with MDI whereas islet transplantation resolved hypoglycemia and further improved glycemic variability regardless of insulin independence.

A diabetes-specific enteral formula improves glycemic variability in patients with type 2 diabetes.

PubMed

Alish, Carolyn J; Garvey, W Timothy; Maki, Kevin C; Sacks, Gordon S; Hustead, Deborah S; Hegazi, Refaat A; Mustad, Vikkie A

2010-06-01

Well-controlled studies have demonstrated that inpatient hyperglycemia is an indicator of poor clinical outcomes, but the use of diabetes-specific enteral formulas in hospitalized patients remains a topic of great debate. In two different protocols, postprandial glycemia and insulinemia were measured in 22 subjects with diabetes fed a diabetes-specific or standard formula (protocol 1). Continuous glucose monitoring was used to assess glucose levels in 12 enterally fed patients with diabetes receiving the standard formula followed by the diabetes-specific formula continuously for 5 days each (protocol 2). End points included postprandial glycemia and insulinemia, glycemic variability (mean amplitude of glycemic excursions [MAGE]), mean glucose, and insulin use. In the postprandial response protocol, the diabetes-specific formula resulted in lower positive areas under the postprandial curve (P < 0.001) and peak glucose (P < 0.001) and insulin (P = 0.017) levels. In the protocol using continuous glucose monitoring, glycemic variability (as measured by MAGE) was lower with continuous administration of the diabetes-specific than the standard formula (64.6 +/- 6.8 mg/dL vs. 110.6 +/-15.3 mg/dL, P = 0.003). Also, administration of the diabetes-specific formula resulted in lower mean glucose concentrations during feeding (171.1 +/- 16.1 vs. 202.1 +/- 17.4 mg/dL, P = 0.024) and insulin requirements (7.8 +/- 2.3 vs. 10.9 +/- 3.3 units/day, P = 0.039) than the standard formula. Relative to the standard formula, the diabetes-specific formula reduced postprandial glycemia, mean glucose, glycemic variability, and short-acting insulin requirements. These results suggest potential clinical usefulness of a diabetes-specific enteral formula for minimizing glycemic excursions in hospitalized patients.

The influence of intra- and inter-annual meteorological variability on dengue transmission: a multi-level modeling analysis

NASA Astrophysics Data System (ADS)

Wen, Tzai-Hung; Chen, Tzu-Hsin

2017-04-01

Dengue fever is one of potentially life-threatening mosquito-borne diseases and IPCC Fifth Assessment Report (AR5) has confirmed that dengue incidence is sensitive to the critical weather conditions, such as effects of temperature. However, previous literature focused on the effects of monthly or weekly average temperature or accumulative precipitation on dengue incidence. The influence of intra- and inter-annual meteorological variability on dengue outbreak is under investigated. The purpose of the study focuses on measuring the effect of the intra- and inter-annual variations of temperature and precipitation on dengue outbreaks. We developed the indices of intra-annual temperature variability are maximum continuity, intermittent, and accumulation of most suitable temperature (MST) for dengue vectors; and also the indices of intra-annual precipitation variability, including the measure of continuity of wetness or dryness during a pre-epidemic period; and rainfall intensity during an epidemic period. We used multi-level modeling to investigate the intra- and inter-annual meteorological variations on dengue outbreaks in southern Taiwan from 1998-2015. Our results indicate that accumulation and maximum continuity of MST are more significant than average temperature on dengue outbreaks. The effect of continuity of wetness during the pre-epidemic period is significantly more positive on promoting dengue outbreaks than the rainfall effect during the epidemic period. Meanwhile, extremely high or low rainfall density during an epidemic period do not promote the spread of dengue epidemics. Our study differentiates the effects of intra- and inter-annual meteorological variations on dengue outbreaks and also provides policy implications for further dengue control under the threats of climate change. Keywords: dengue fever, meteorological variations, multi-level model

Stronger steerability criterion for more uncertain continuous-variable systems

NASA Astrophysics Data System (ADS)

Chowdhury, Priyanka; Pramanik, Tanumoy; Majumdar, A. S.

2015-10-01

We derive a fine-grained uncertainty relation for the measurement of two incompatible observables on a single quantum system of continuous variables, and show that continuous-variable systems are more uncertain than discrete-variable systems. Using the derived fine-grained uncertainty relation, we formulate a stronger steering criterion that is able to reveal the steerability of NOON states that has hitherto not been possible using other criteria. We further obtain a monogamy relation for our steering inequality which leads to an, in principle, improved lower bound on the secret key rate of a one-sided device independent quantum key distribution protocol for continuous variables.

Robustness of quantum key distribution with discrete and continuous variables to channel noise

NASA Astrophysics Data System (ADS)

Lasota, Mikołaj; Filip, Radim; Usenko, Vladyslav C.

2017-06-01

We study the robustness of quantum key distribution protocols using discrete or continuous variables to the channel noise. We introduce the model of such noise based on coupling of the signal to a thermal reservoir, typical for continuous-variable quantum key distribution, to the discrete-variable case. Then we perform a comparison of the bounds on the tolerable channel noise between these two kinds of protocols using the same noise parametrization, in the case of implementation which is perfect otherwise. Obtained results show that continuous-variable protocols can exhibit similar robustness to the channel noise when the transmittance of the channel is relatively high. However, for strong loss discrete-variable protocols are superior and can overcome even the infinite-squeezing continuous-variable protocol while using limited nonclassical resources. The requirement on the probability of a single-photon production which would have to be fulfilled by a practical source of photons in order to demonstrate such superiority is feasible thanks to the recent rapid development in this field.

Using Electronic Health Record (EHR) “Big Data” to Examine the Influence of Nurse Continuity on a Hospital-Acquired Never Event

PubMed Central

STIFTER, Janet; YAO, Yingwei; LODHI, Muhammad Kamran; LOPEZ, Karen Dunn; KHOKHAR, Ashfaq; WILKIE, Diana J.; KEENAN, Gail M.

2015-01-01

Background There is little research demonstrating the influence of nurse continuity on patient outcomes despite an intuitive belief that continuity of care makes a difference in care outcomes. Objective To examine the influence of nurse continuity (the number of consecutive care days by the same/consistent RN[s]) on the prevention of hospital-acquired pressure ulcers (HAPU). Method A secondary use of data from the Hands on Automated Nursing Data System (HANDS) was performed for this comparative study. The HANDS is a nursing plan of care (POC) “big data” database containing 42,403 episodes documented by 787 nurses, on 9 units, in four hospitals and includes nurse staffing and patient characteristics. Via data mining, we created an analytic dataset of 840 care episodes, 210 with and 630 without HAPUs, matched by nursing unit, patient age, and patient characteristics. Logistic regression analysis determined the influence of nurse continuity and additional nurse-staffing variables on the presence of HAPUs. Results Poor nurse continuity (Continuity Index=.21-.42 [1.0=optimal continuity]) was noted on all nine study units. Nutrition, mobility, perfusion, hydration, and skin problems on admission as well as patient age were associated with HAPUs (p<.001). Controlling for patient characteristics, nurse continuity and the interactions between nurse continuity and other nurse-staffing variables were not significantly associated with HAPU development. Discussion Patient characteristics including nutrition, mobility, and perfusion were associated with HAPUs, but nurse continuity was not. One study implication is that to reduce the incidence of HAPUs the most effective resource utilization might be in the continued development of best practices to address patient characteristics that lead to pressure ulcer vulnerability rather than a focus on nurse staffing. PMID:26325278

A randomised controlled trial of flow driver and bubble continuous positive airway pressure in preterm infants in a resource-limited setting.

PubMed

Mazmanyan, P; Mellor, K; Doré, C J; Modi, N

2016-01-01

The variable-flow flow driver (FD; EME) and continuous-flow bubble (Fisher-Paykel) continuous positive airway pressure (CPAP) systems are widely used. As these differ in cost and technical requirements, determining comparative efficacy is important particularly where resources are limited. We performed a randomised, controlled, equivalence trial of CPAP systems. We specified the margin of equivalence as 2 days. We analysed binary variables by logistical regression adjusted for gestation, and log transformed continuous variables by multiple linear regression adjusted for gestation, sex and antenatal steroids. A neonatal unit with no blood gas analyser or surfactant availability and limited X-ray and laboratory facilities Neonates <37 weeks of gestation. We provided CPAP at delivery followed by randomisation to FD or bubble (B). Primary outcome included total days receiving CPAP; secondary outcomes included days receiving CPAP, supplemental oxygen, ventilation, death, pneumothorax and nasal excoriation. We randomised 125 infants (B 66, FD 59). Differences in infant outcomes on B and FD were not statistically significant. The median (range) for CPAP days for survivors was B 0.8 (0.04 to 17.5), FD 0.5 (0.04 to 5.3). B:FD (95% CI) ratios were CPAP days 1.3 (0.9 to 2.1), CPAP plus supplementary oxygen days 1.2 (0.7 to 1.9). B:FD (95% CI) ORs were death 2.3 (0.2 to 28), ventilation 2.1 (0.5 to 9), nasal excoriation 1.2 (0.2 to 8) and pneumothorax 2.4 (0.2 to 26). In a resource-limited setting we found B CPAP equivalent to FD CPAP in the total number of days receiving CPAP within a margin of 2 days. ISRCTN22578364. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Aeroelastic Wing Shaping Control Subject to Actuation Constraints.

NASA Technical Reports Server (NTRS)

Swei, Sean Shan-Min; Nguyen, Nhan

2014-01-01

This paper considers the control of coupled aeroelastic aircraft model which is configured with Variable Camber Continuous Trailing Edge Flap (VCCTEF) system. The relative deflection between two adjacent flaps is constrained and this actuation constraint is accounted for when designing an effective control law for suppressing the wing vibration. A simple tuned-mass damper mechanism with two attached masses is used as an example to demonstrate the effectiveness of vibration suppression with confined motion of tuned masses. In this paper, a dynamic inversion based pseudo-control hedging (PCH) and bounded control approach is investigated, and for illustration, it is applied to the NASA Generic Transport Model (GTM) configured with VCCTEF system.

Current concepts in blood glucose monitoring

PubMed Central

Khadilkar, Kranti Shreesh; Bandgar, Tushar; Shivane, Vyankatesh; Lila, Anurag; Shah, Nalini

2013-01-01

Blood glucose monitoring has evolved over the last century. The concept of adequate glycemic control and minimum glycemic variability requires an ideal, accurate and reliable glucose monitoring system. The search for an ideal blood glucose monitoring system still continues. This review explains the various blood glucose monitoring systems with special focus on the monitoring systems like self- monitored blood glucose (SMBG) and continuous glucose monitoring system (CGMS). It also focuses on the newer concepts of blood glucose monitoring and their incorporation in routine clinical management of diabetes mellitus. PMID:24910827

Optogenetic feedback control of neural activity

PubMed Central

Newman, Jonathan P; Fong, Ming-fai; Millard, Daniel C; Whitmire, Clarissa J; Stanley, Garrett B; Potter, Steve M

2015-01-01

Optogenetic techniques enable precise excitation and inhibition of firing in specified neuronal populations and artifact-free recording of firing activity. Several studies have suggested that optical stimulation provides the precision and dynamic range requisite for closed-loop neuronal control, but no approach yet permits feedback control of neuronal firing. Here we present the ‘optoclamp’, a feedback control technology that provides continuous, real-time adjustments of bidirectional optical stimulation in order to lock spiking activity at specified targets over timescales ranging from seconds to days. We demonstrate how this system can be used to decouple neuronal firing levels from ongoing changes in network excitability due to multi-hour periods of glutamatergic or GABAergic neurotransmission blockade in vitro as well as impinging vibrissal sensory drive in vivo. This technology enables continuous, precise optical control of firing in neuronal populations in order to disentangle causally related variables of circuit activation in a physiologically and ethologically relevant manner. DOI: http://dx.doi.org/10.7554/eLife.07192.001 PMID:26140329

The effects of 2 weeks of interval vs continuous walking training on glycaemic control and whole-body oxidative stress in individuals with type 2 diabetes: a controlled, randomised, crossover trial.

PubMed

Karstoft, Kristian; Clark, Margaret A; Jakobsen, Ida; Müller, Ida A; Pedersen, Bente K; Solomon, Thomas P J; Ried-Larsen, Mathias

2017-03-01

The aim of this study was to evaluate the effects of oxygen consumption-matched short-term interval walking training (IWT) vs continuous walking training (CWT) on glycaemic control, including glycaemic variability, in individuals with type 2 diabetes. We also assessed whether any training-induced improvements in glycaemic control were associated with systemic oxidative stress levels. Participants (n = 14) with type 2 diabetes completed a crossover trial using three interventions (control intervention [CON], CWT and IWT), each lasting 2 weeks. These were performed in a randomised order (computerised generated randomisation) and separated by washout periods of 4 or 8 weeks after CON or training interventions, respectively. Training included ten supervised treadmill sessions, lasting 60 min/session, and was performed at the research facility. CWT was performed at moderate walking speed (75.6% ± 2.5% of walking peak oxygen consumption [[Formula: see text

Attention following traumatic brain injury: Neuropsychological and driving simulator data, and association with sleep, sleepiness, and fatigue.

PubMed

Beaulieu-Bonneau, Simon; Fortier-Brochu, Émilie; Ivers, Hans; Morin, Charles M

2017-03-01

The objectives of this study were to compare individuals with traumatic brain injury (TBI) and healthy controls on neuropsychological tests of attention and driving simulation performance, and explore their relationships with participants' characteristics, sleep, sleepiness, and fatigue. Participants were 22 adults with moderate or severe TBI (time since injury ≥ one year) and 22 matched controls. They completed three neuropsychological tests of attention, a driving simulator task, night-time polysomnographic recordings, and subjective ratings of sleepiness and fatigue. Results showed that participants with TBI exhibited poorer performance compared to controls on measures tapping speed of information processing and sustained attention, but not on selective attention measures. On the driving simulator task, a greater variability of the vehicle lateral position was observed in the TBI group. Poorer performance on specific subsets of neuropsychological variables was associated with poorer sleep continuity in the TBI group, and with a greater increase in subjective sleepiness in both groups. No significant relationship was found between cognitive performance and fatigue. These findings add to the existing evidence that speed of information processing is still impaired several years after moderate to severe TBI. Sustained attention could also be compromised. Attention seems to be associated with sleep continuity and daytime sleepiness; this interaction needs to be explored further.

Continuous glucose monitoring to assess the ecologic validity of dietary glycemic index and glycemic load123

PubMed Central

Ebbeling, Cara B; Wadden, Thomas A; Ludwig, David S

2011-01-01

Background: The circumstances under which the glycemic index (GI) and glycemic load (GL) are derived do not reflect real-world eating behavior. Thus, the ecologic validity of these constructs is incompletely known. Objective: This study examined the relation of dietary intake to glycemic response when foods are consumed under free-living conditions. Design: Participants were 26 overweight or obese adults with type 2 diabetes who participated in a randomized trial of lifestyle modification. The current study includes baseline data, before initiation of the intervention. Participants wore a continuous glucose monitor and simultaneously kept a food diary for 3 d. The dietary variables included GI, GL, and intakes of energy, fat, protein, carbohydrate, sugars, and fiber. The glycemic response variables included AUC, mean and SD of continuous glucose monitoring (CGM) values, percentage of CGM values in euglycemic and hyperglycemic ranges, and mean amplitude of glycemic excursions. Relations between daily dietary intake and glycemic outcomes were examined. Results: Data were available from 41 d of monitoring. Partial correlations, controlled for energy intake, indicated that GI or GL was significantly associated with each glycemic response outcome. In multivariate analyses, dietary GI accounted for 10% to 18% of the variance in each glycemic variable, independent of energy and carbohydrate intakes (P < 0.01). Conclusions: The data support the ecologic validity of the GI and GL constructs in free-living obese adults with type 2 diabetes. GI was the strongest and most consistent independent predictor of glycemic stability and variability. PMID:22071699

An interactive approach based on a discrete differential evolution algorithm for a class of integer bilevel programming problems

NASA Astrophysics Data System (ADS)

Li, Hong; Zhang, Li; Jiao, Yong-Chang

2016-07-01

This paper presents an interactive approach based on a discrete differential evolution algorithm to solve a class of integer bilevel programming problems, in which integer decision variables are controlled by an upper-level decision maker and real-value or continuous decision variables are controlled by a lower-level decision maker. Using the Karush--Kuhn-Tucker optimality conditions in the lower-level programming, the original discrete bilevel formulation can be converted into a discrete single-level nonlinear programming problem with the complementarity constraints, and then the smoothing technique is applied to deal with the complementarity constraints. Finally, a discrete single-level nonlinear programming problem is obtained, and solved by an interactive approach. In each iteration, for each given upper-level discrete variable, a system of nonlinear equations including the lower-level variables and Lagrange multipliers is solved first, and then a discrete nonlinear programming problem only with inequality constraints is handled by using a discrete differential evolution algorithm. Simulation results show the effectiveness of the proposed approach.

Development of speech motor control: lip movement variability.

PubMed

Schötz, Susanne; Frid, Johan; Löfqvist, Anders

2013-06-01

This study examined variability of lip movements across repetitions of the same utterance as a function of age in Swedish speakers. The specific purpose was to extend earlier findings by examining variability in both phase and amplitude. Subjects were 50 typically developed native Swedish children and adults (28 females, 22 males, aged 5 to 31 yr). Lip movements were recorded during 15 to 20 repetitions of a short Swedish phrase using three-dimensional articulography. After correction for head movements, the kinematic records were expressed in a maxilla-based coordinate system. Movement onset and offset of the utterance were identified using kinematic landmarks. The Euclidean distance between receivers on the upper and lower lips was calculated and subjected to functional data analysis to assess both phase and amplitude variability. Results show a decrease in both indices as a function of age, with a greater reduction of amplitude variability. There was no difference between males and females for either index. The two indices were moderately correlated with each other, suggesting that they capture different aspects of speech production. Utterance duration also decreased with age, but variability was unrelated to duration. The standard deviation of utterance duration also decreased with age. The present results thus suggest that age related changes in speech motor control continue up until 30 years of age.

[Metabolic control in the critically ill patient an update: hyperglycemia, glucose variability hypoglycemia and relative hypoglycemia].

PubMed

Pérez-Calatayud, Ángel Augusto; Guillén-Vidaña, Ariadna; Fraire-Félix, Irving Santiago; Anica-Malagón, Eduardo Daniel; Briones Garduño, Jesús Carlos; Carrillo-Esper, Raúl

Metabolic changes of glucose in critically ill patients increase morbidity and mortality. The appropriate level of blood glucose has not been established so far and should be adjusted for different populations. However concepts such as glucose variability and relative hypoglycemia of critically ill patients are concepts that are changing management methods and achieving closer monitoring. The purpose of this review is to present new data about the management and metabolic control of patients in critical areas. Currently glucose can no longer be regarded as an innocent element in critical patients; both hyperglycemia and hypoglycemia increase morbidity and mortality of patients. Protocols and better instruments for continuous measurement are necessary to achieve the metabolic control of our patients. Copyright © 2016 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

Characterization of Common Measures of Heart Period Variability in Healthy Human Subjects: Implications for Patient Monitoring

DTIC Science & Technology

2010-01-01

application of these metrics to patient monitoring must take into account the impact of other external stimuli, such as pain, anxiety and activity status...in short-term HRV analysis. Biomed Tech 2006; 51: 190–193. 45. Hayano J, Taylor JA, Yamada A, et al. Continuous assessment of hemodynamic control by

Selection of stand variables in southern Maine for making volume estimates from aerial photos

Treesearch

Earl J. Rogers; Gene Avery; Roy A. Chapman

1959-01-01

Aerial photographs are used widely in forest inventories. But there is a continuing need for improving the techniques of photo interpretation and making more efficient use of photographs. When the number or intensity of sample ground plots is controlled by airphoto classifications, a reliable stratification of the timber area is a must.

Fast packet switching algorithms for dynamic resource control over ATM networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsang, R.P.; Keattihananant, P.; Chang, T.

1996-12-01

Real-time continuous media traffic, such as digital video and audio, is expected to comprise a large percentage of the network load on future high speed packet switch networks such as ATM. A major feature which distinguishes high speed networks from traditional slower speed networks is the large amount of data the network must process very quickly. For efficient network usage, traffic control mechanisms are essential. Currently, most mechanisms for traffic control (such as flow control) have centered on the support of Available Bit Rate (ABR), i.e., non real-time, traffic. With regard to ATM, for ABR traffic, two major types ofmore » schemes which have been proposed are rate- control and credit-control schemes. Neither of these schemes are directly applicable to Real-time Variable Bit Rate (VBR) traffic such as continuous media traffic. Traffic control for continuous media traffic is an inherently difficult problem due to the time- sensitive nature of the traffic and its unpredictable burstiness. In this study, we present a scheme which controls traffic by dynamically allocating/de- allocating resources among competing VCs based upon their real-time requirements. This scheme incorporates a form of rate- control, real-time burst-level scheduling and link-link flow control. We show analytically potential performance improvements of our rate- control scheme and present a scheme for buffer dimensioning. We also present simulation results of our schemes and discuss the tradeoffs inherent in maintaining high network utilization and statistically guaranteeing many users` Quality of Service.« less

Extraction of Lateral-Directional Stability and Control Derivatives for the Basic F-18 Aircraft at High Angles of Attack

NASA Technical Reports Server (NTRS)

Iliff, Kenneth W.; Wang, Kon-Sheng Charles

1997-01-01

The results of parameter identification to determine the lateral-directional stability and control derivatives of an F-18 research aircraft in its basic hardware and software configuration are presented. The derivatives are estimated from dynamic flight data using a specialized identification program developed at NASA Dryden Flight Research Center. The formulation uses the linearized aircraft equations of motions in their continuous/discrete form and a maximum likelihood estimator that accounts for both state and measurement noise. State noise is used to model the uncommanded forcing function caused by unsteady aerodynamics, such as separated and vortical flows, over the aircraft. The derivatives are plotted as functions of angle of attack between 3 deg and 47 deg and compared with wind-tunnel predictions. The quality of the derivative estimates obtained by parameter identification is somewhat degraded because the maneuvers were flown with the aircraft's control augmentation system engaged, which introduced relatively high correlations between the control variables and response variables as a result of control motions from the feedback control system.

Turbine Engine Control Synthesis. Volume 1. Optimal Controller Synthesis and Demonstration

DTIC Science & Technology

1975-03-01

Nomenclature (Continued) Symbol Deseription M Matrix (of Table 12) M Mach number N Rotational speed, rpm N ’ Nonlinear rotational speed, rpm P Power lever... P Pressure, N /m 2; bfh/ft 2 PLA Power lever angle PR = PT3/PT2 Pressure ratio ( P Power, ft-lbf/sec Q Matrix (of Table 30) R Universal gas constant, 53...function, i = 1, 2, 3, ... in Inlet n Stage number designation out Outlet p Variable associated with particle s Static condition _se Static condition

Attitude estimation of earth orbiting satellites by decomposed linear recursive filters

NASA Technical Reports Server (NTRS)

Kou, S. R.

1975-01-01

Attitude estimation of earth orbiting satellites (including Large Space Telescope) subjected to environmental disturbances and noises was investigated. Modern control and estimation theory is used as a tool to design an efficient estimator for attitude estimation. Decomposed linear recursive filters for both continuous-time systems and discrete-time systems are derived. By using this accurate estimation of the attitude of spacecrafts, state variable feedback controller may be designed to achieve (or satisfy) high requirements of system performance.

The Integration of Continuous and Discrete Latent Variable Models: Potential Problems and Promising Opportunities

ERIC Educational Resources Information Center

Bauer, Daniel J.; Curran, Patrick J.

2004-01-01

Structural equation mixture modeling (SEMM) integrates continuous and discrete latent variable models. Drawing on prior research on the relationships between continuous and discrete latent variable models, the authors identify 3 conditions that may lead to the estimation of spurious latent classes in SEMM: misspecification of the structural model,…

Climate controls photosynthetic capacity more than leaf nitrogen contents

NASA Astrophysics Data System (ADS)

Ali, A. A.; Xu, C.; McDowell, N. G.

2013-12-01

Global vegetation models continue to lack the ability to make reliable predictions because the photosynthetic capacity varies a lot with growth conditions, season and among species. It is likely that vegetation models link photosynthetic capacity to concurrent changes in leaf nitrogen content only. To improve the predictions of the vegetation models, there is an urgent need to review species growth conditions and their seasonal response to changing climate. We sampled the global distribution of the Vcmax (maximum carboxylation rates) data of various species across different environmental gradients from the literature and standardized its value to 25 degree Celcius. We found that species explained the largest variation in (1) the photosynthetic capacity and (2) the proportion of nitrogen allocated for rubisco (PNcb). Surprisingly, climate variables explained more variations in photosynthetic capacity as well as PNcb than leaf nitrogen content and/or specific leaf area. The chief climate variables that explain variation in photosynthesis and PNcb were radiation, temperature and daylength. Our analysis suggests that species have the greatest control over photosynthesis and PNcb. Further, compared to leaf nitrogen content and/or specific leaf area, climate variables have more control over photosynthesis and PNcb. Therefore, climate variables should be incorporated in the global vegetation models when making predictions about the photosynthetic capacity.

Effects of body lean and visual information on the equilibrium maintenance during stance.

PubMed

Duarte, Marcos; Zatsiorsky, Vladimir M

2002-09-01

Maintenance of equilibrium was tested in conditions when humans assume different leaning postures during upright standing. Subjects ( n=11) stood in 13 different body postures specified by visual center of pressure (COP) targets within their base of support (BOS). Different types of visual information were tested: continuous presentation of visual target, no vision after target presentation, and with simultaneous visual feedback of the COP. The following variables were used to describe the equilibrium maintenance: the mean of the COP position, the area of the ellipse covering the COP sway, and the resultant median frequency of the power spectral density of the COP displacement. The variability of the COP displacement, quantified by the COP area variable, increased when subjects occupied leaning postures, irrespective of the kind of visual information provided. This variability also increased when vision was removed in relation to when vision was present. Without vision, drifts in the COP data were observed which were larger for COP targets farther away from the neutral position. When COP feedback was given in addition to the visual target, the postural control system did not control stance better than in the condition with only visual information. These results indicate that the visual information is used by the postural control system at both short and long time scales.

High glycemic variability assessed by continuous glucose monitoring after surgical treatment of obesity by gastric bypass.

PubMed

Hanaire, Helene; Bertrand, Monelle; Guerci, Bruno; Anduze, Yves; Guillaume, Eric; Ritz, Patrick

2011-06-01

Obesity surgery elicits complex changes in glucose metabolism that are difficult to observe with discontinuous glucose measurements. We aimed to evaluate glucose variability after gastric bypass by continuous glucose monitoring (CGM) in a real-life setting. CGM was performed for 4.2 ± 1.3 days in three groups of 10 subjects each: patients who had undergone gastric bypass and who were referred for postprandial symptoms compatible with mild hypoglycemia, nonoperated diabetes controls, and healthy controls. The maximum interstitial glucose (IG), SD of IG values, and mean amplitude of glucose excursions (MAGE) were significantly higher in operated patients and in diabetes controls than in healthy controls. The time to the postprandial peak IG was significantly shorter in operated patients (42.8 ± 6.0 min) than in diabetes controls (82.2 ± 11.1 min, P = 0.0002), as were the rates of glucose increase to the peak (2.4 ± 1.6 vs. 1.2 ± 0.3 mg/mL/min; P = 0.041). True hypoglycemia (glucose <60 mg/dL) was rare: the symptoms were probably more related to the speed of IG decrease than to the glucose level achieved. Half of the operated patients, mostly those with a diabetes background before surgery, had postprandial glucose concentrations above 200 mg/dL (maximum IG, 306 ± 59 mg/dL), in contrast to the normal glucose concentrations in the fasting state and 2 h postmeal. Glucose variability is exaggerated after gastric bypass, combining unusually high and early hyperglycemic peaks and rapid IG decreases. This might account for postprandial symptoms mimicking hypoglycemia but often seen without true hypoglycemia. Early postprandial hyperglycemia might be underestimated if glucose measurements are done 2 h postmeal.

In the hot seat : Insolation and ENSO controls on vegetation productivity in tropical Africa inferred from NDVI

NASA Astrophysics Data System (ADS)

Ivory, S.; Russell, J. L.; Cohen, A. S.

2010-12-01

Threats to tropical biodiversity with serious and costly implications for both ecosystems and human well-being in Africa have led the IPCC to classify this region as vulnerable to negative impacts from climate change. Yet little is known about how vegetation communities respond to altered patterns of rainfall and evaporation. Paleoclimate records within the tropics can help answer questions about how vegetation response to climate forcing changes over time. However, sparse spatial extent of records and uncertainty surrounding the climate-vegetation relationship complicate these insights. Understanding the climatic mechanisms involved in landscape change at all temporal scales creates the need for quantitative constraints of the modern relationship between climatic controls, hydrology, and vegetation. Though modern observational data can help elucidate this relationship, low resolution and complicated rainfall/vegetation associations make them less than ideal. Satellite data of vegetation productivity (NDVI) with continuous high-resolution spatial coverage provides a robust and elegant tool for identifying the link between global and regional controls and vegetation. We use regression analyses of variables either previously proposed or potentially important in regulating Afro-tropical vegetation (insolation, out-going long-wave radiation, geopotential height, Southern Oscillation Index, Indian Ocean Dipole, Indian Monsoon precipitation, sea-level pressure, surface wind, sea-surface temperature) on continuous, time-varying spatial fields of 8km NDVI for sub-Saharan Africa. These analyses show the importance of global atmospheric controls in producing regional intra-annual and inter-annual vegetation variability. Dipole patterns emerge primarily correlated with both the seasonal and inter-annual extent of the Intertropical Convergence Zone (ITCZ). Inter-annual ITCZ variability drives patterns in African vegetation resulting from the effect of insolation anomalies and ENSO events on atmospheric circulation rather than sea surface temperatures or teleconnections to mid/high latitudes. Global controls on tropical atmospheric circulation regulate vegetation throughout sub-Saharan Africa on many time scales through alteration of dry season length and moisture convergence, rather than precipitation amount.

Sleep and mental disorders: A meta-analysis of polysomnographic research.

PubMed

Baglioni, Chiara; Nanovska, Svetoslava; Regen, Wolfram; Spiegelhalder, Kai; Feige, Bernd; Nissen, Christoph; Reynolds, Charles F; Riemann, Dieter

2016-09-01

Investigating sleep in mental disorders has the potential to reveal both disorder-specific and transdiagnostic psychophysiological mechanisms. This meta-analysis aimed at determining the polysomnographic (PSG) characteristics of several mental disorders. Relevant studies were searched through standard strategies. Controlled PSG studies evaluating sleep in affective, anxiety, eating, pervasive developmental, borderline and antisocial personality disorders, attention-deficit-hyperactivity disorder (ADHD), and schizophrenia were included. PSG variables of sleep continuity, depth, and architecture, as well as rapid-eye movement (REM) sleep were considered. Calculations were performed with the "Comprehensive Meta-Analysis" and "R" software. Using random effects modeling, for each disorder and each variable, a separate meta-analysis was conducted if at least 3 studies were available for calculation of effect sizes as standardized means (Hedges' g). Sources of variability, that is, sex, age, and mental disorders comorbidity, were evaluated in subgroup analyses. Sleep alterations were evidenced in all disorders, with the exception of ADHD and seasonal affective disorders. Sleep continuity problems were observed in most mental disorders. Sleep depth and REM pressure alterations were associated with affective, anxiety, autism and schizophrenia disorders. Comorbidity was associated with enhanced REM sleep pressure and more inhibition of sleep depth. No sleep parameter was exclusively altered in 1 condition; however, no 2 conditions shared the same PSG profile. Sleep continuity disturbances imply a transdiagnostic imbalance in the arousal system likely representing a basic dimension of mental health. Sleep depth and REM variables might play a key role in psychiatric comorbidity processes. Constellations of sleep alterations may define distinct disorders better than alterations in 1 single variable. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Violation of Bell's Inequality Using Continuous Variable Measurements

NASA Astrophysics Data System (ADS)

Thearle, Oliver; Janousek, Jiri; Armstrong, Seiji; Hosseini, Sara; Schünemann Mraz, Melanie; Assad, Syed; Symul, Thomas; James, Matthew R.; Huntington, Elanor; Ralph, Timothy C.; Lam, Ping Koy

2018-01-01

A Bell inequality is a fundamental test to rule out local hidden variable model descriptions of correlations between two physically separated systems. There have been a number of experiments in which a Bell inequality has been violated using discrete-variable systems. We demonstrate a violation of Bell's inequality using continuous variable quadrature measurements. By creating a four-mode entangled state with homodyne detection, we recorded a clear violation with a Bell value of B =2.31 ±0.02 . This opens new possibilities for using continuous variable states for device independent quantum protocols.

Discrete-continuous variable structural synthesis using dual methods

NASA Technical Reports Server (NTRS)

Schmit, L. A.; Fleury, C.

1980-01-01

Approximation concepts and dual methods are extended to solve structural synthesis problems involving a mix of discrete and continuous sizing type of design variables. Pure discrete and pure continuous variable problems can be handled as special cases. The basic mathematical programming statement of the structural synthesis problem is converted into a sequence of explicit approximate primal problems of separable form. These problems are solved by constructing continuous explicit dual functions, which are maximized subject to simple nonnegativity constraints on the dual variables. A newly devised gradient projection type of algorithm called DUAL 1, which includes special features for handling dual function gradient discontinuities that arise from the discrete primal variables, is used to find the solution of each dual problem. Computational implementation is accomplished by incorporating the DUAL 1 algorithm into the ACCESS 3 program as a new optimizer option. The power of the method set forth is demonstrated by presenting numerical results for several example problems, including a pure discrete variable treatment of a metallic swept wing and a mixed discrete-continuous variable solution for a thin delta wing with fiber composite skins.

Production of sugarcane and tropical grasses as a renewable energy source. Second annual report, 1978-1979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1979-01-01

Reseach continued on tropical grasses from Saccharum and related genera as sources of intensively-produced, solar-dried biomass. Categories of candidate grasses include short-, intermediate-, and long-rotation species. These categories are based on the time interval required for maximum dry matter production, and on future management requirements of energy crops for intensive co-production with food crop commodities. Year 1 studies at the greenhouse and field-plot levels were continued and broadened during Year 2. This included candidate screening, importation and quarantine of new clones, breeding, controlled nitrogen and water regimes, chemical growth control, tissue expansion and maturation control, seeding rates, harvest frequency, andmore » variable row spacing. Second-year studies were extended to the project's field-scale and mechanized-harvest phases. These include initial economic anayses for the short-rotation phases. These include initial economic analyses for the short-rotation category of candidate species.« less

Method for continuous control of composition and doping of pulsed laser deposited films

DOEpatents

Lowndes, Douglas H.; McCamy, James W.

1995-01-01

A method for growing a deposit upon a substrate of semiconductor material involves the utilization of pulsed laser deposition techniques within a low-pressure gas environment. The substrate and a target of a first material are positioned within a deposition chamber and a low-pressure gas atmosphere is developed within the chamber. The substrate is then heated, and the target is irradiated, so that atoms of the target material are ablated from the remainder of the target, while atoms of the gas simultaneously are adsorbed on the substrate/film surface. The ablated atoms build up upon the substrate, together with the adsorbed gas atoms to form the thin-film deposit on the substrate. By controlling the pressure of the gas of the chamber atmosphere, the composition of the formed deposit can be controlled, and films of continuously variable composition or doping can be grown from a single target of fixed composition.

Cardiorespiratory interaction with continuous positive airway pressure

PubMed Central

Bonafini, Sara; Fava, Cristiano; Steier, Joerg

2018-01-01

The treatment of choice for obstructive sleep apnoea (OSA) is continuous positive airway pressure therapy (CPAP). Since its introduction in clinical practice, CPAP has been used in various clinical conditions with variable and heterogeneous outcomes. In addition to the well-known effects on the upper airway CPAP impacts on intrathoracic pressures, haemodynamics and blood pressure (BP) control. However, short- and long-term effects of CPAP therapy depend on multiple variables which include symptoms, underlying condition, pressure used, treatment acceptance, compliance and usage. CPAP can alter long-term cardiovascular risk in patients with cardiorespiratory conditions. Furthermore, the effect of CPAP on the awake patient differs from the effect on the patients while asleep, and this might contribute to discomfort and removal of the use interface. The purpose of this review is to highlight the physiological impact of CPAP on the cardiorespiratory system, including short-term benefits and long-term outcomes. PMID:29445529

CHAMP - Camera, Handlens, and Microscope Probe

NASA Technical Reports Server (NTRS)

Mungas, G. S.; Beegle, L. W.; Boynton, J.; Sepulveda, C. A.; Balzer, M. A.; Sobel, H. R.; Fisher, T. A.; Deans, M.; Lee, P.

2005-01-01

CHAMP (Camera, Handlens And Microscope Probe) is a novel field microscope capable of color imaging with continuously variable spatial resolution from infinity imaging down to diffraction-limited microscopy (3 micron/pixel). As an arm-mounted imager, CHAMP supports stereo-imaging with variable baselines, can continuously image targets at an increasing magnification during an arm approach, can provide precision range-finding estimates to targets, and can accommodate microscopic imaging of rough surfaces through a image filtering process called z-stacking. Currently designed with a filter wheel with 4 different filters, so that color and black and white images can be obtained over the entire Field-of-View, future designs will increase the number of filter positions to include 8 different filters. Finally, CHAMP incorporates controlled white and UV illumination so that images can be obtained regardless of sun position, and any potential fluorescent species can be identified so the most astrobiologically interesting samples can be identified.

Practical continuous-variable quantum key distribution without finite sampling bandwidth effects.

PubMed

Li, Huasheng; Wang, Chao; Huang, Peng; Huang, Duan; Wang, Tao; Zeng, Guihua

2016-09-05

In a practical continuous-variable quantum key distribution system, finite sampling bandwidth of the employed analog-to-digital converter at the receiver's side may lead to inaccurate results of pulse peak sampling. Then, errors in the parameters estimation resulted. Subsequently, the system performance decreases and security loopholes are exposed to eavesdroppers. In this paper, we propose a novel data acquisition scheme which consists of two parts, i.e., a dynamic delay adjusting module and a statistical power feedback-control algorithm. The proposed scheme may improve dramatically the data acquisition precision of pulse peak sampling and remove the finite sampling bandwidth effects. Moreover, the optimal peak sampling position of a pulse signal can be dynamically calibrated through monitoring the change of the statistical power of the sampled data in the proposed scheme. This helps to resist against some practical attacks, such as the well-known local oscillator calibration attack.

Design studies of continuously variable transmissions for electric vehicles

NASA Technical Reports Server (NTRS)

Parker, R. J.; Loewenthal, S. H.; Fischer, G. K.

1981-01-01

Preliminary design studies were performed on four continuously variable transmission (CVT) concepts for use with a flywheel equipped electric vehicle of 1700 kg gross weight. Requirements of the CVT's were a maximum torque of 450 N-m (330 lb-ft), a maximum output power of 75 kW (100 hp), and a flywheel speed range of 28,000 to 14,000 rpm. Efficiency, size, weight, cost, reliability, maintainability, and controls were evaluated for each of the four concepts which included a steel V-belt type, a flat rubber belt type, a toroidal traction type, and a cone roller traction type. All CVT's exhibited relatively high calculated efficiencies (68 percent to 97 percent) over a broad range of vehicle operating conditions. Estimated weight and size of these transmissions were comparable to or less than equivalent automatic transmission. The design of each concept was carried through the design layout stage.

Epidemiologic programs for computers and calculators. A microcomputer program for multiple logistic regression by unconditional and conditional maximum likelihood methods.

PubMed

Campos-Filho, N; Franco, E L

1989-02-01

A frequent procedure in matched case-control studies is to report results from the multivariate unmatched analyses if they do not differ substantially from the ones obtained after conditioning on the matching variables. Although conceptually simple, this rule requires that an extensive series of logistic regression models be evaluated by both the conditional and unconditional maximum likelihood methods. Most computer programs for logistic regression employ only one maximum likelihood method, which requires that the analyses be performed in separate steps. This paper describes a Pascal microcomputer (IBM PC) program that performs multiple logistic regression by both maximum likelihood estimation methods, which obviates the need for switching between programs to obtain relative risk estimates from both matched and unmatched analyses. The program calculates most standard statistics and allows factoring of categorical or continuous variables by two distinct methods of contrast. A built-in, descriptive statistics option allows the user to inspect the distribution of cases and controls across categories of any given variable.

Design and Modeling of a Variable Heat Rejection Radiator

NASA Technical Reports Server (NTRS)

Miller, Jennifer R.; Birur, Gajanana C.; Ganapathi, Gani B.; Sunada, Eric T.; Berisford, Daniel F.; Stephan, Ryan

2011-01-01

Variable Heat Rejection Radiator technology needed for future NASA human rated & robotic missions Primary objective is to enable a single loop architecture for human-rated missions (1) Radiators are typically sized for maximum heat load in the warmest continuous environment resulting in a large panel area (2) Large radiator area results in fluid being susceptible to freezing at low load in cold environment and typically results in a two-loop system (3) Dual loop architecture is approximately 18% heavier than single loop architecture (based on Orion thermal control system mass) (4) Single loop architecture requires adaptability to varying environments and heat loads

Maximum-entropy probability distributions under Lp-norm constraints

NASA Technical Reports Server (NTRS)

Dolinar, S.

1991-01-01

Continuous probability density functions and discrete probability mass functions are tabulated which maximize the differential entropy or absolute entropy, respectively, among all probability distributions with a given L sub p norm (i.e., a given pth absolute moment when p is a finite integer) and unconstrained or constrained value set. Expressions for the maximum entropy are evaluated as functions of the L sub p norm. The most interesting results are obtained and plotted for unconstrained (real valued) continuous random variables and for integer valued discrete random variables. The maximum entropy expressions are obtained in closed form for unconstrained continuous random variables, and in this case there is a simple straight line relationship between the maximum differential entropy and the logarithm of the L sub p norm. Corresponding expressions for arbitrary discrete and constrained continuous random variables are given parametrically; closed form expressions are available only for special cases. However, simpler alternative bounds on the maximum entropy of integer valued discrete random variables are obtained by applying the differential entropy results to continuous random variables which approximate the integer valued random variables in a natural manner. All the results are presented in an integrated framework that includes continuous and discrete random variables, constraints on the permissible value set, and all possible values of p. Understanding such as this is useful in evaluating the performance of data compression schemes.

Evaluation of Two New Indices of Blood Pressure Variability Using Postural Change in Older Fallers.

PubMed

Goh, Choon-Hian; Ng, Siew-Cheok; Kamaruzzaman, Shahrul B; Chin, Ai-Vyrn; Poi, Philip J H; Chee, Kok Han; Imran, Z Abidin; Tan, Maw Pin

2016-05-01

To evaluate the utility of blood pressure variability (BPV) calculated using previously published and newly introduced indices using the variables falls and age as comparators.While postural hypotension has long been considered a risk factor for falls, there is currently no documented evidence on the relationship between BPV and falls.A case-controlled study involving 25 fallers and 25 nonfallers was conducted. Systolic (SBPV) and diastolic blood pressure variability (DBPV) were assessed using 5 indices: standard deviation (SD), standard deviation of most stable continuous 120 beats (staSD), average real variability (ARV), root mean square of real variability (RMSRV), and standard deviation of real variability (SDRV). Continuous beat-to-beat blood pressure was recorded during 10 minutes' supine rest and 3 minutes' standing.Standing SBPV was significantly higher than supine SBPV using 4 indices in both groups. The standing-to-supine-BPV ratio (SSR) was then computed for each subject (staSD, ARV, RMSRV, and SDRV). Standing-to-supine ratio for SBPV was significantly higher among fallers compared to nonfallers using RMSRV and SDRV (P = 0.034 and P = 0.025). Using linear discriminant analysis (LDA), 3 indices (ARV, RMSRV, and SDRV) of SSR SBPV provided accuracies of 61.6%, 61.2%, and 60.0% for the prediction of falls which is comparable with timed-up and go (TUG), 64.4%.This study suggests that SSR SBPV using RMSRV and SDRV is a potential predictor for falls among older patients, and deserves further evaluation in larger prospective studies.

Suppression of chaos via control of energy flow

NASA Astrophysics Data System (ADS)

Guo, Shengli; Ma, Jun; Alsaedi, Ahmed

2018-03-01

Continuous energy supply is critical and important to support oscillating behaviour; otherwise, the oscillator will die. For nonlinear and chaotic circuits, enough energy supply is also important to keep electric devices working. In this paper, Hamilton energy is calculated for dimensionless dynamical system (e.g., the chaotic Lorenz system) using Helmholtz's theorem. The Hamilton energy is considered as a new variable and then the dynamical system is controlled by using the scheme of energy feedback. It is found that chaos can be suppressed even when intermittent feedback scheme is applied. This scheme is effective to control chaos and to stabilise other dynamical systems.

Predictors of Global Self-Worth and Academic Performance among Regular Education, Learning Disabled, and Continuation High School Students.

ERIC Educational Resources Information Center

Wiest, Dudley J.; Wong, Eugene H.; Kreil, Dennis A.

1998-01-01

The ability of measures of perceived competence, control, and autonomy support to predict self-worth and academic performance was studied across groups of high school students. Stepwise regression analyses indicate these variables in model predict self-worth and grade point average. In addition, levels of school status and depression predict…

Classroom Management Training, Teaching Experience and Gender: Do These Variables Impact Teachers' Attitudes and Beliefs toward Classroom Management Style?

ERIC Educational Resources Information Center

Martin, Nancy K.; Yin, Zenong; Mayall, Hayley

2006-01-01

This study represents a continuation of research efforts to further refine the Attitudes and Beliefs on Classroom Control (ABCC) Inventory. The purposes of this study were to investigate the: (1) impact of classroom management training on classroom management style; (2) differences in attitudes toward classroom management between novice and…

A Geometrical Framework for Covariance Matrices of Continuous and Categorical Variables

ERIC Educational Resources Information Center

Vernizzi, Graziano; Nakai, Miki

2015-01-01

It is well known that a categorical random variable can be represented geometrically by a simplex. Accordingly, several measures of association between categorical variables have been proposed and discussed in the literature. Moreover, the standard definitions of covariance and correlation coefficient for continuous random variables have been…

Mixture Factor Analysis for Approximating a Nonnormally Distributed Continuous Latent Factor with Continuous and Dichotomous Observed Variables

ERIC Educational Resources Information Center

Wall, Melanie M.; Guo, Jia; Amemiya, Yasuo

2012-01-01

Mixture factor analysis is examined as a means of flexibly estimating nonnormally distributed continuous latent factors in the presence of both continuous and dichotomous observed variables. A simulation study compares mixture factor analysis with normal maximum likelihood (ML) latent factor modeling. Different results emerge for continuous versus…

Severe postpartum haemorrhage after vaginal delivery: a statistical process control chart to report seven years of continuous quality improvement.

PubMed

Dupont, Corinne; Occelli, Pauline; Deneux-Tharaux, Catherine; Touzet, Sandrine; Duclos, Antoine; Bouvier-Colle, Marie-Hélène; Rudigoz, René-Charles; Huissoud, Cyril

2014-07-01

Severe postpartum haemorrhage after vaginal delivery: a statistical process control chart to report seven years of continuous quality improvement To use statistical process control charts to describe trends in the prevalence of severe postpartum haemorrhage after vaginal delivery. This assessment was performed 7 years after we initiated a continuous quality improvement programme that began with regular criteria-based audits Observational descriptive study, in a French maternity unit in the Rhône-Alpes region. Quarterly clinical audit meetings to analyse all cases of severe postpartum haemorrhage after vaginal delivery and provide feedback on quality of care with statistical process control tools. The primary outcomes were the prevalence of severe PPH after vaginal delivery and its quarterly monitoring with a control chart. The secondary outcomes included the global quality of care for women with severe postpartum haemorrhage, including the performance rate of each recommended procedure. Differences in these variables between 2005 and 2012 were tested. From 2005 to 2012, the prevalence of severe postpartum haemorrhage declined significantly, from 1.2% to 0.6% of vaginal deliveries (p<0.001). Since 2010, the quarterly rate of severe PPH has not exceeded the upper control limits, that is, been out of statistical control. The proportion of cases that were managed consistently with the guidelines increased for all of their main components. Implementation of continuous quality improvement efforts began seven years ago and used, among other tools, statistical process control charts. During this period, the prevalence of severe postpartum haemorrhage after vaginal delivery has been reduced by 50%. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

[Indications for the use of continuous subcutaneous insulin infusion in pediatric patients with type 1 diabetes mellitus].

PubMed

Espejel-Huerta, Diana; Antillón-Ferreira, Carlos Alberto; Iglesias-Leboreiro, José; Bernárdez-Zapata, Isabel; Martínez-Ramos Méndez, Angélica; Rendón-Macías, Mario Enrique

2016-01-01

Diabetes is a serious health problem for pediatrics. In pediatric patients control depends on correct insulin administration. The most usual is subcutaneous administration according to the glycemic control. The aim was to analyze the indications for continuous subcutaneous insulin infusion (CSII) in type 1 diabetes mellitus (T1DM) children and adolescents. It was carried out a descriptive study in patients from 1 to 16 years with T1DM who underwent CSII therapy. The main cause to use this therapy was analyzed, and also if that cause was different regarding age, sex and disease progression. 61 patients underwent CSII therapy. The median age at the beginning of treatment was 9 years old; 43 patients (71.6 %) had more than one year of diagnosis. The main reasons to use CSII were: 42.6 % had to improve their quality of life, 34.4 % had to reduce the high glycemic variability, 13.1 % had to control severe recurrent hypoglycemia, and 9.8 % had to control their HbA1c. For children under 6 years of age (n = 14) the more frequent indication were recurrent hypoglycemia and to improve their quality of life; children from 6 to 12 years of age (n = 27) had to improve their quality of life, and in children over 12 years CSII was indicated for high glycemic variability and severe recurrent hypoglycemia. There was no different indication related between sexes. Improve their quality of life and reach a better glycemic control were the main reasons to start CSII in our patients.

Opinions and Satisfaction Regarding Continuous Subcutaneous Insulin Infusion Therapy in Adult Patients with Type 1 Diabetes

PubMed Central

Nishio, Ikuko; Chujo, Masami; Ohkura, Tsuyoshi; Kataoka, Hideyuki

2015-01-01

Background This study examined the treatment satisfaction of type 1 diabetic patients undergoing continuous subcutaneous insulin infusion (CSII) therapy, and patients’ thoughts regarding CSII. Methods We provided a self-administered questionnaire survey over the internet. Participants were 106 individuals with type-one diabetes aged 20 years or older, undergoing CSII. The survey examined patients’ treatment satisfaction, and their thoughts regarding CSII. Descriptive statistics were calculated. We compared relationships between treatment satisfaction and other variables using the Kruskal-Wallis rank sum test, and performed content analysis on participants’ thoughts regarding CSII. Results Regarding treatment satisfaction, the response, “neither of them” was the most frequent. Comparing relationships between treatment satisfaction and other variables, significant differences were found for the variables “age,” “presence of dissatisfaction regarding doctors’ response,” and “presence of a significant medical expense burden.” Participants’ thoughts regarding CSII were classified into 10 categories. Conclusion Participants expressed positive evaluations, such as that their blood sugar control had improved due to CSII, and that they perceived improvement in their health. Participants also expressed negative evaluations, however, such as that medical expenses resulting from CSII were high, and that these expenses may cause distress and future economic insecurity. In future, patients may benefit from nursing support that allows patients to confidently continue with CSII. PMID:26538796

CCM Continuity Constraint Method: A finite-element computational fluid dynamics algorithm for incompressible Navier-Stokes fluid flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, P. T.

1993-09-01

As the field of computational fluid dynamics (CFD) continues to mature, algorithms are required to exploit the most recent advances in approximation theory, numerical mathematics, computing architectures, and hardware. Meeting this requirement is particularly challenging in incompressible fluid mechanics, where primitive-variable CFD formulations that are robust, while also accurate and efficient in three dimensions, remain an elusive goal. This dissertation asserts that one key to accomplishing this goal is recognition of the dual role assumed by the pressure, i.e., a mechanism for instantaneously enforcing conservation of mass and a force in the mechanical balance law for conservation of momentum. Provingmore » this assertion has motivated the development of a new, primitive-variable, incompressible, CFD algorithm called the Continuity Constraint Method (CCM). The theoretical basis for the CCM consists of a finite-element spatial semi-discretization of a Galerkin weak statement, equal-order interpolation for all state-variables, a 0-implicit time-integration scheme, and a quasi-Newton iterative procedure extended by a Taylor Weak Statement (TWS) formulation for dispersion error control. Original contributions to algorithmic theory include: (a) formulation of the unsteady evolution of the divergence error, (b) investigation of the role of non-smoothness in the discretized continuity-constraint function, (c) development of a uniformly H 1 Galerkin weak statement for the Reynolds-averaged Navier-Stokes pressure Poisson equation, (d) derivation of physically and numerically well-posed boundary conditions, and (e) investigation of sparse data structures and iterative methods for solving the matrix algebra statements generated by the algorithm.« less

Intelligent Control Electromagnetic Actuated Continuously Variable Transmission System for Passenger Car

NASA Astrophysics Data System (ADS)

Rahman, Ataur; Sharif, Sazzad; Mohiuddin, AKM; Faris Ismail, Ahmed; Izan, Sany Ihsan

2017-03-01

Continuously variable transmission (CVT) system transmits the engine /battery power to the car driving wheel smoothly and efficiently. Cars with CVT produces some noise and slow acceleration to meet the car power demand on initial start-ups and slow speed. The car noise is produced as a result of CVT adjustment the engine speed with the hydraulic pressure. The current CVT problems incurred due to the slow response of hydraulic pressure and CVT fluid viscosity due to the development of heat.The aim of this study is to develop electromagnetic actuated CVT (EMA-CVT) with intelligent switching controlling system (ICS). The experimental results of ¼ scale EMA shows that it make the acceleration time of the car in 3.5-5 sec which is 40% less than the hydraulic CVT in the market. The EMA develops the electromagnetic force in the ranged of 350 -1200 N for the supply current in the range of 10-15 amp. This study introduced fuzzy intelligent system (FIS) to predict the EMA system dynamic behaviour in order to identify the current control for the EMA actuation during operation of the CVT. It is expecting that the up scale EMA-CVT would reduce the 75% of vehicle power transmission loss by accelerating vehicle in 5 sec and save the IC engine power consumption about 20% which will makes the vehicle energy efficient (EEV) and reduction of green house gas reduction.

How Robust Is Linear Regression with Dummy Variables?

ERIC Educational Resources Information Center

Blankmeyer, Eric

2006-01-01

Researchers in education and the social sciences make extensive use of linear regression models in which the dependent variable is continuous-valued while the explanatory variables are a combination of continuous-valued regressors and dummy variables. The dummies partition the sample into groups, some of which may contain only a few observations.…

Continuation Power Flow with Variable-Step Variable-Order Nonlinear Predictor

NASA Astrophysics Data System (ADS)

Kojima, Takayuki; Mori, Hiroyuki

This paper proposes a new continuation power flow calculation method for drawing a P-V curve in power systems. The continuation power flow calculation successively evaluates power flow solutions through changing a specified value of the power flow calculation. In recent years, power system operators are quite concerned with voltage instability due to the appearance of deregulated and competitive power markets. The continuation power flow calculation plays an important role to understand the load characteristics in a sense of static voltage instability. In this paper, a new continuation power flow with a variable-step variable-order (VSVO) nonlinear predictor is proposed. The proposed method evaluates optimal predicted points confirming with the feature of P-V curves. The proposed method is successfully applied to IEEE 118-bus and IEEE 300-bus systems.

A variable-mode stator consequent pole memory machine

NASA Astrophysics Data System (ADS)

Yang, Hui; Lyu, Shukang; Lin, Heyun; Zhu, Z. Q.

2018-05-01

In this paper, a variable-mode concept is proposed for the speed range extension of a stator-consequent-pole memory machine (SCPMM). An integrated permanent magnet (PM) and electrically excited control scheme is utilized to simplify the flux-weakening control instead of relatively complicated continuous PM magnetization control. Due to the nature of memory machine, the magnetization state of low coercive force (LCF) magnets can be easily changed by applying either a positive or negative current pulse. Therefore, the number of PM poles may be changed to satisfy the specific performance requirement under different speed ranges, i.e. the machine with all PM poles can offer high torque output while that with half PM poles provides wide constant power range. In addition, the SCPMM with non-magnetized PMs can be considered as a dual-three phase electrically excited reluctance machine, which can be fed by an open-winding based dual inverters that provide direct current (DC) bias excitation to further extend the speed range. The effectiveness of the proposed variable-mode operation for extending its operating region and improving the system reliability is verified by both finite element analysis (FEA) and experiments.

Dynamic Modeling of the Main Blow in Basic Oxygen Steelmaking Using Measured Step Responses

NASA Astrophysics Data System (ADS)

Kattenbelt, Carolien; Roffel, B.

2008-10-01

In the control and optimization of basic oxygen steelmaking, it is important to have an understanding of the influence of control variables on the process. However, important process variables such as the composition of the steel and slag cannot be measured continuously. The decarburization rate and the accumulation rate of oxygen, which can be derived from the generally measured waste gas flow and composition, are an indication of changes in steel and slag composition. The influence of the control variables on the decarburization rate and the accumulation rate of oxygen can best be determined in the main blow period. In this article, the measured step responses of the decarburization rate and the accumulation rate of oxygen to step changes in the oxygen blowing rate, lance height, and the addition rate of iron ore during the main blow are presented. These measured step responses are subsequently used to develop a dynamic model for the main blow. The model consists of an iron oxide and a carbon balance and an additional equation describing the influence of the lance height and the oxygen blowing rate on the decarburization rate. With this simple dynamic model, the measured step responses can be explained satisfactorily.

Control Systems Engineering in Continuous Pharmaceutical Manufacturing May 20-21, 2014 Continuous Manufacturing Symposium.

PubMed

Myerson, Allan S; Krumme, Markus; Nasr, Moheb; Thomas, Hayden; Braatz, Richard D

2015-03-01

This white paper provides a perspective of the challenges, research needs, and future directions for control systems engineering in continuous pharmaceutical processing. The main motivation for writing this paper is to facilitate the development and deployment of control systems technologies so as to ensure quality of the drug product. Although the main focus is on small-molecule pharmaceutical products, most of the same statements apply to biological drug products. An introduction to continuous manufacturing and control systems is followed by a discussion of the current status and technical needs in process monitoring and control, systems integration, and risk analysis. Some key points are that: (1) the desired objective in continuous manufacturing should be the satisfaction of all critical quality attributes (CQAs), not for all variables to operate at steady-state values; (2) the design of start-up and shutdown procedures can significantly affect the economic operation of a continuous manufacturing process; (3) the traceability of material as it moves through the manufacturing facility is an important consideration that can at least in part be addressed using residence time distributions; and (4) the control systems technologies must assure quality in the presence of disturbances, dynamics, uncertainties, nonlinearities, and constraints. Direct measurement, first-principles and empirical model-based predictions, and design space approaches are described for ensuring that CQA specifications are met. Ways are discussed for universities, regulatory bodies, and industry to facilitate working around or through barriers to the development of control systems engineering technologies for continuous drug manufacturing. Industry and regulatory bodies should work with federal agencies to create federal funding mechanisms to attract faculty to this area. Universities should hire faculty interested in developing first-principles models and control systems technologies for drug manufacturing that are easily transportable to industry. Industry can facilitate the move to continuous manufacturing by working with universities on the conception of new continuous pharmaceutical manufacturing process unit operations that have the potential to make major improvements in product quality, controllability, or reduced capital and/or operating costs. Regulatory bodies should ensure that: (1) regulations and regulatory practices promote, and do not derail, the development and implementation of continuous manufacturing and control systems engineering approaches; (2) the individuals who approve specific regulatory filings are sufficiently trained to make good decisions regarding control systems approaches; (3) provide regulatory clarity and eliminate/reduce regulatory risks; (4) financially support the development of high-quality training materials for use of undergraduate students, graduate students, industrial employees, and regulatory staff; (5) enhance the training of their own technical staff by financially supporting joint research projects with universities in the development of continuous pharmaceutical manufacturing processes and the associated control systems engineering theory, numerical algorithms, and software; and (6) strongly encourage the federal agencies that support research to fund these research areas. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Control systems engineering in continuous pharmaceutical manufacturing. May 20-21, 2014 Continuous Manufacturing Symposium.

PubMed

Myerson, Allan S; Krumme, Markus; Nasr, Moheb; Thomas, Hayden; Braatz, Richard D

2015-03-01

This white paper provides a perspective of the challenges, research needs, and future directions for control systems engineering in continuous pharmaceutical processing. The main motivation for writing this paper is to facilitate the development and deployment of control systems technologies so as to ensure quality of the drug product. Although the main focus is on small-molecule pharmaceutical products, most of the same statements apply to biological drug products. An introduction to continuous manufacturing and control systems is followed by a discussion of the current status and technical needs in process monitoring and control, systems integration, and risk analysis. Some key points are that: (1) the desired objective in continuous manufacturing should be the satisfaction of all critical quality attributes (CQAs), not for all variables to operate at steady-state values; (2) the design of start-up and shutdown procedures can significantly affect the economic operation of a continuous manufacturing process; (3) the traceability of material as it moves through the manufacturing facility is an important consideration that can at least in part be addressed using residence time distributions; and (4) the control systems technologies must assure quality in the presence of disturbances, dynamics, uncertainties, nonlinearities, and constraints. Direct measurement, first-principles and empirical model-based predictions, and design space approaches are described for ensuring that CQA specifications are met. Ways are discussed for universities, regulatory bodies, and industry to facilitate working around or through barriers to the development of control systems engineering technologies for continuous drug manufacturing. Industry and regulatory bodies should work with federal agencies to create federal funding mechanisms to attract faculty to this area. Universities should hire faculty interested in developing first-principles models and control systems technologies for drug manufacturing that are easily transportable to industry. Industry can facilitate the move to continuous manufacturing by working with universities on the conception of new continuous pharmaceutical manufacturing process unit operations that have the potential to make major improvements in product quality, controllability, or reduced capital and/or operating costs. Regulatory bodies should ensure that: (1) regulations and regulatory practices promote, and do not derail, the development and implementation of continuous manufacturing and control systems engineering approaches; (2) the individuals who approve specific regulatory filings are sufficiently trained to make good decisions regarding control systems approaches; (3) provide regulatory clarity and eliminate/reduce regulatory risks; (4) financially support the development of high-quality training materials for use of undergraduate students, graduate students, industrial employees, and regulatory staff; (5) enhance the training of their own technical staff by financially supporting joint research projects with universities in the development of continuous pharmaceutical manufacturing processes and the associated control systems engineering theory, numerical algorithms, and software; and (6) strongly encourage the federal agencies that support research to fund these research areas. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

A Review of Modern Control Strategies for Clinical Evaluation of Propofol Anesthesia Administration Employing Hypnosis Level Regulation.

PubMed

Ilyas, Muhammad; Butt, Muhammad Fasih Uddin; Bilal, Muhammad; Mahmood, Khalid; Khaqan, Ali; Ali Riaz, Raja

2017-01-01

Regulating the depth of hypnosis during surgery is one of the major objectives of an anesthesia infusion system. Continuous administration of Propofol infusion during surgical procedures is essential but it unduly increases the load of an anesthetist working in a multitasking scenario in the operation theatre. Manual and target controlled infusion systems are not appropriate to handle instabilities like blood pressure and heart rate changes arising due to interpatient and intrapatient variability. Patient safety, large interindividual variability, and less postoperative effects are the main factors motivating automation in anesthesia administration. The idea of automated system for Propofol infusion excites control engineers to come up with more sophisticated systems that can handle optimum delivery of anesthetic drugs during surgery and avoid postoperative effects. A linear control technique is applied initially using three compartmental pharmacokinetic and pharmacodynamic models. Later on, sliding mode control and model predicative control achieve considerable results with nonlinear sigmoid model. Chattering and uncertainties are further improved by employing adaptive fuzzy control and H ∞ control. The proposed sliding mode control scheme can easily handle the nonlinearities and achieve an optimum hypnosis level as compared to linear control schemes, hence preventing mishaps such as underdosing and overdosing of anesthesia.

A Review of Modern Control Strategies for Clinical Evaluation of Propofol Anesthesia Administration Employing Hypnosis Level Regulation

PubMed Central

Ilyas, Muhammad; Bilal, Muhammad; Mahmood, Khalid; Ali Riaz, Raja

2017-01-01

Regulating the depth of hypnosis during surgery is one of the major objectives of an anesthesia infusion system. Continuous administration of Propofol infusion during surgical procedures is essential but it unduly increases the load of an anesthetist working in a multitasking scenario in the operation theatre. Manual and target controlled infusion systems are not appropriate to handle instabilities like blood pressure and heart rate changes arising due to interpatient and intrapatient variability. Patient safety, large interindividual variability, and less postoperative effects are the main factors motivating automation in anesthesia administration. The idea of automated system for Propofol infusion excites control engineers to come up with more sophisticated systems that can handle optimum delivery of anesthetic drugs during surgery and avoid postoperative effects. A linear control technique is applied initially using three compartmental pharmacokinetic and pharmacodynamic models. Later on, sliding mode control and model predicative control achieve considerable results with nonlinear sigmoid model. Chattering and uncertainties are further improved by employing adaptive fuzzy control and H∞ control. The proposed sliding mode control scheme can easily handle the nonlinearities and achieve an optimum hypnosis level as compared to linear control schemes, hence preventing mishaps such as underdosing and overdosing of anesthesia. PMID:28466018

Heart rate variability in normal-weight patients with polycystic ovary syndrome.

PubMed

Kilit, Celal; Paşalı Kilit, Türkan

2017-05-01

Polycystic ovary syndrome (PCOS) is an endocrine disease closely related to several risk factors of cardiovascular disease. Obese women with PCOS show altered autonomic modulation. The results of studies investigating cardiac autonomic functions of normal-weight women with PCOS are conflicting. The aim of the study was to assess the reactivity of cardiac sympathovagal balance in normal-weight women with PCOS by heart rate variability analysis. We examined the heart rate variability in 60 normal-weight women with PCOS and compared them with that in 60 age-matched healthy women having a similar metabolic profile. Time and frequency domain parameters of heart rate variability were analyzed based on 5-min-long continuous electrocardiography recordings for the following 3 periods: (1) during rest in supine position, (2) during controlled breathing, and (3) during isometric handgrip exercise. Time and frequency domain parameters of heart rate variability for the 3 periods assessed were similar in the two groups. Although modified Ferriman-Gallwey score and serum testosterone and luteinizing hormone levels were significantly higher in women with PCOS, homeostatic model assessment-insulin resistance (HOMA-IR) was not different the between the PCOS and control groups. There were no significant correlations between serum testosterone levels and heart rate variability parameters among the study population. The findings of this study suggest that the reactivity of cardiac sympathovagal balance is not altered in normal-weight women with PCOS having a normal HOMA-IR.

Intra-individual reaction time variability based on ex-Gaussian distribution as a potential endophenotype for attention-deficit/hyperactivity disorder.

PubMed

Lin, H-Y; Hwang-Gu, S-L; Gau, S S-F

2015-07-01

Intra-individual variability in reaction time (IIV-RT), defined by standard deviation of RT (RTSD), is considered as an endophenotype for attention-deficit/hyperactivity disorder (ADHD). Ex-Gaussian distributions of RT, rather than RTSD, could better characterize moment-to-moment fluctuations in neuropsychological performance. However, data of response variability based on ex-Gaussian parameters as an endophenotypic candidate for ADHD are lacking. We assessed 411 adolescents with clinically diagnosed ADHD based on the DSM-IV-TR criteria as probands, 138 unaffected siblings, and 138 healthy controls. The output parameters, mu, sigma, and tau, of an ex-Gaussian RT distribution were derived from the Conners' continuous performance test. Multi-level models controlling for sex, age, comorbidity, and use of methylphenidate were applied. Compared with unaffected siblings and controls, ADHD probands had elevated sigma value, omissions, commissions, and mean RT. Unaffected siblings formed an intermediate group in-between probands and controls in terms of tau value and RTSD. There was no between-group difference in mu value. Conforming to a context-dependent nature, unaffected siblings still had an intermediate tau value in-between probands and controls across different interstimulus intervals. Our findings suggest IIV-RT represented by tau may be a potential endophenotype for inquiry into genetic underpinnings of ADHD in the context of heterogeneity. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Comprehensive Modeling and Analysis of Rotorcraft Variable Speed Propulsion System With Coupled Engine/Transmission/Rotor Dynamics

NASA Technical Reports Server (NTRS)

DeSmidt, Hans A.; Smith, Edward C.; Bill, Robert C.; Wang, Kon-Well

2013-01-01

This project develops comprehensive modeling and simulation tools for analysis of variable rotor speed helicopter propulsion system dynamics. The Comprehensive Variable-Speed Rotorcraft Propulsion Modeling (CVSRPM) tool developed in this research is used to investigate coupled rotor/engine/fuel control/gearbox/shaft/clutch/flight control system dynamic interactions for several variable rotor speed mission scenarios. In this investigation, a prototypical two-speed Dual-Clutch Transmission (DCT) is proposed and designed to achieve 50 percent rotor speed variation. The comprehensive modeling tool developed in this study is utilized to analyze the two-speed shift response of both a conventional single rotor helicopter and a tiltrotor drive system. In the tiltrotor system, both a Parallel Shift Control (PSC) strategy and a Sequential Shift Control (SSC) strategy for constant and variable forward speed mission profiles are analyzed. Under the PSC strategy, selecting clutch shift-rate results in a design tradeoff between transient engine surge margins and clutch frictional power dissipation. In the case of SSC, clutch power dissipation is drastically reduced in exchange for the necessity to disengage one engine at a time which requires a multi-DCT drive system topology. In addition to comprehensive simulations, several sections are dedicated to detailed analysis of driveline subsystem components under variable speed operation. In particular an aeroelastic simulation of a stiff in-plane rotor using nonlinear quasi-steady blade element theory was conducted to investigate variable speed rotor dynamics. It was found that 2/rev and 4/rev flap and lag vibrations were significant during resonance crossings with 4/rev lagwise loads being directly transferred into drive-system torque disturbances. To capture the clutch engagement dynamics, a nonlinear stick-slip clutch torque model is developed. Also, a transient gas-turbine engine model based on first principles mean-line compressor and turbine approximations is developed. Finally an analysis of high frequency gear dynamics including the effect of tooth mesh stiffness variation under variable speed operation is conducted including experimental validation. Through exploring the interactions between the various subsystems, this investigation provides important insights into the continuing development of variable-speed rotorcraft propulsion systems.

Provider continuity in family medicine: does it make a difference for total health care costs?

PubMed

De Maeseneer, Jan M; De Prins, Lutgarde; Gosset, Christiane; Heyerick, Jozef

2003-01-01

International comparisons of health care systems have shown a relationship at the macro level between a well-structured primary health care plan and lower total health care costs. The objective of this study was to assess whether provider continuity with a family physician is related to lower health care costs using the individual patient as the unit of analysis. We undertook a study of a stratified sample of patients (age, sex, region, insurance company) for which 2 cohorts were constructed based on the patients' utilization pattern of family medicine (provider continuity or not). Patient utilization patterns were observed for 2 years. The setting was the Belgian health care system. The participants were 4,134 members of the 2 largest health insurance companies in 2 regions (Aalst and Liège). The main outcome measures were the total health care costs of patients with and without provider continuity with a family physician, controlling for variables known to influence health care utilization (need factors, predisposing factors, enabling factors). Bivariate analyses showed that patients who were visiting the same family physician had a lower total cost for medical care. A multivariate linear regression showed that provider continuity with a family physician was one of the most important explanatory variables related to the total health care cost. Provider continuity with a family physician is related to lower total health care costs. This finding brings evidence to the debate on the importance of structured primary health care (with high continuity for family practice) for a cost-effective health policy.

Integration of a computerized two-finger gripper for robot workstation safety

NASA Technical Reports Server (NTRS)

Sneckenberger, John E.; Yoshikata, Kazuki

1988-01-01

A microprocessor-based controller has been developed that continuously monitors and adjusts the gripping force applied by a special two-finger gripper. This computerized force sensing gripper system enables the endeffector gripping action to be independently detected and corrected. The gripping force applied to a manipulated object is real-time monitored for problem situations, situations which can occur during both planned and errant robot arm manipulation. When unspecified force conditions occur at the gripper, the gripping force controller initiates specific reactions to cause dynamic corrections to the continuously variable gripping action. The force controller for this intelligent gripper has been interfaced to the controller of an industrial robot. The gripper and robot controllers communicate to accomplish the successful completion of normal gripper operations as well as unexpected hazardous situations. An example of an unexpected gripping condition would be the sudden deformation of the object being manipulated by the robot. The capabilities of the interfaced gripper-robot system to apply workstation safety measures (e.g., stop the robot) when these unexpected gripping effects occur have been assessed.

A Framework for Dynamic Constraint Reasoning Using Procedural Constraints

NASA Technical Reports Server (NTRS)

Jonsson, Ari K.; Frank, Jeremy D.

1999-01-01

Many complex real-world decision and control problems contain an underlying constraint reasoning problem. This is particularly evident in a recently developed approach to planning, where almost all planning decisions are represented by constrained variables. This translates a significant part of the planning problem into a constraint network whose consistency determines the validity of the plan candidate. Since higher-level choices about control actions can add or remove variables and constraints, the underlying constraint network is invariably highly dynamic. Arbitrary domain-dependent constraints may be added to the constraint network and the constraint reasoning mechanism must be able to handle such constraints effectively. Additionally, real problems often require handling constraints over continuous variables. These requirements present a number of significant challenges for a constraint reasoning mechanism. In this paper, we introduce a general framework for handling dynamic constraint networks with real-valued variables, by using procedures to represent and effectively reason about general constraints. The framework is based on a sound theoretical foundation, and can be proven to be sound and complete under well-defined conditions. Furthermore, the framework provides hybrid reasoning capabilities, as alternative solution methods like mathematical programming can be incorporated into the framework, in the form of procedures.

Discovering Cepheid and RR Lyrae Stars: Pan-STARRS Science Archive @ STScI and Robotically Controlled Telescopes

NASA Astrophysics Data System (ADS)

Johnson, Elizabeth; Strolger, Louis-Gregory; Engle, Scott G.; Anderson, Richard I.; Rest, Armin; Calamida, Annalisa; Dosovitz Fox, Ori; Laney, David

2017-01-01

Cepheid and RR Lyrae stars are an integral part of the cosmic distance ladder and are also useful for studying galactic structure and stellar ages. This project aims to greatly expand the number of known periodic variables in our galaxy by identifying candidates in the PanSTARRS-1 3pi catalog, and carrying out systematically targeted characterization with robotically controlled telescopes. Candidate targets are selected from available detection tables based on color and variability indices and are then fully vetted using robotic telescopes: the RCT 1.3 meter (Kitt Peak National Observatory) and RATIR 1.5 meter (Mexico). Here we present work to develop a full, semi-automated prescription for candidate selection, targeted follow-up photometry, cataloging, and classification, which allows the review of approximately 25 variable candidates every two weeks. We make comparisons of our sample selection and purity from a similar study based on Pan-STARRS data (Hernitschek et al. 2016), as well as candidates identified in Gaia DR1. The goal, through continued observation and analysis, is to identify at least 10,000 new variables, hundreds of which will be new Cepheid and RR Lyrae stars.

Implementation of Temperature Sequential Controller on Variable Speed Drive

NASA Astrophysics Data System (ADS)

Cheong, Z. X.; Barsoum, N. N.

2008-10-01

There are many pump and motor installations with quite extensive speed variation, such as Sago conveyor, heating, ventilation and air conditioning (HVAC) and water pumping system. A common solution for these applications is to run several fixed speed motors in parallel, with flow control accomplish by turning the motors on and off. This type of control method causes high in-rush current, and adds a risk of damage caused by pressure transients. This paper explains the design and implementation of a temperature speed control system for use in industrial and commercial sectors. Advanced temperature speed control can be achieved by using ABB ACS800 variable speed drive-direct torque sequential control macro, programmable logic controller and temperature transmitter. The principle of direct torque sequential control macro (DTC-SC) is based on the control of torque and flux utilizing the stator flux field orientation over seven preset constant speed. As a result of continuous comparison of ambient temperature to the references temperatures; electromagnetic torque response is particularly fast to the motor state and it is able maintain constant speeds. Experimental tests have been carried out by using ABB ACS800-U1-0003-2, to validate the effectiveness and dynamic respond of ABB ACS800 against temperature variation, loads, and mechanical shocks.

Statistical Methods for Quality Control of Steel Coils Manufacturing Process using Generalized Linear Models

NASA Astrophysics Data System (ADS)

García-Díaz, J. Carlos

2009-11-01

Fault detection and diagnosis is an important problem in process engineering. Process equipments are subject to malfunctions during operation. Galvanized steel is a value added product, furnishing effective performance by combining the corrosion resistance of zinc with the strength and formability of steel. Fault detection and diagnosis is an important problem in continuous hot dip galvanizing and the increasingly stringent quality requirements in automotive industry has also demanded ongoing efforts in process control to make the process more robust. When faults occur, they change the relationship among these observed variables. This work compares different statistical regression models proposed in the literature for estimating the quality of galvanized steel coils on the basis of short time histories. Data for 26 batches were available. Five variables were selected for monitoring the process: the steel strip velocity, four bath temperatures and bath level. The entire data consisting of 48 galvanized steel coils was divided into sets. The first training data set was 25 conforming coils and the second data set was 23 nonconforming coils. Logistic regression is a modeling tool in which the dependent variable is categorical. In most applications, the dependent variable is binary. The results show that the logistic generalized linear models do provide good estimates of quality coils and can be useful for quality control in manufacturing process.

Changes of heart rate variability and prefrontal oxygenation during Tai Chi practice versus arm ergometer cycling.

PubMed

Lu, Xi; Hui-Chan, Christina Wan-Ying; Tsang, William Wai-Nam

2016-11-01

[Purpose] Exercise has been shown to improve cardiovascular fitness and cognitive function. Whether the inclusion of mind over exercise would increase parasympathetic control of the heart and brain activities more than general exercise at a similar intensity is not known. The aim of this study was to compare the effects of Tai Chi (mind-body exercise) versus arm ergometer cycling (body-focused exercise) on the heart rate variability and prefrontal oxygenation level. [Subjects and Methods] A Tai Chi master was invited to perform Tai Chi and arm ergometer cycling with similar exercise intensity on two separate days. Heart rate variability and prefrontal oxyhemoglobin levels were measured continuously by a RR recorder and near-infrared spectroscopy, respectively. [Results] During Tai Chi exercise, spectral analysis of heart rate variability demonstrated a higher high-frequency power as well as a lower low-frequency/high-frequency ratio than during ergometer cycling, suggesting increased parasympathetic and decreased sympathetic control of the heart. Also, prefrontal oxyhemoglobin and total hemoglobin levels were higher than those during arm ergometer exercise. [Conclusion] These findings suggest that increased parasympathetic control of the heart and prefrontal activities may be associated with Tai Chi practice. Having a "mind" component in Tai Chi could be more beneficial for older adults' cardiac health and cognitive function than body-focused ergometer cycling.

Linear and angular control of circular walking in healthy older adults and subjects with cerebellar ataxia.

PubMed

Goodworth, Adam D; Paquette, Caroline; Jones, Geoffrey Melvill; Block, Edward W; Fletcher, William A; Hu, Bin; Horak, Fay B

2012-05-01

Linear and angular control of trunk and leg motion during curvilinear navigation was investigated in subjects with cerebellar ataxia and age-matched control subjects. Subjects walked with eyes open around a 1.2-m circle. The relationship of linear to angular motion was quantified by determining the ratios of trunk linear velocity to trunk angular velocity and foot linear position to foot angular position. Errors in walking radius (the ratio of linear to angular motion) also were quantified continuously during the circular walk. Relative variability of linear and angular measures was compared using coefficients of variation (CoV). Patterns of variability were compared using power spectral analysis for the trunk and auto-covariance analysis for the feet. Errors in radius were significantly increased in patients with cerebellar damage as compared to controls. Cerebellar subjects had significantly larger CoV of feet and trunk in angular, but not linear, motion. Control subjects also showed larger CoV in angular compared to linear motion of the feet and trunk. Angular and linear components of stepping differed in that angular, but not linear, foot placement had a negative correlation from one stride to the next. Thus, walking in a circle was associated with more, and a different type of, variability in angular compared to linear motion. Results are consistent with increased difficulty of, and role of the cerebellum in, control of angular trunk and foot motion for curvilinear locomotion.

An inverter/controller subsystem optimized for photovoltaic applications

NASA Technical Reports Server (NTRS)

Pickrell, R. L.; Merrill, W. C.; Osullivan, G.

1978-01-01

Conversion of solar array dc power to ac power stimulated the specification, design, and simulation testing of an inverter/controller subsystem tailored to the photovoltaic power source characteristics. This paper discusses the optimization of the inverter/controller design as part of an overall Photovoltaic Power System (PPS) designed for maximum energy extraction from the solar array. The special design requirements for the inverter/controller include: (1) a power system controller (PSC) to control continuously the solar array operating point at the maximum power level based on variable solar insolation and cell temperatures; and (2) an inverter designed for high efficiency at rated load and low losses at light loadings to conserve energy. It must be capable of operating connected to the utility line at a level set by an external controller (PSC).

Microwave Switching and Attenuation with Superconductors.

NASA Astrophysics Data System (ADS)

Poulin, Grant Darcy

1995-01-01

The discovery of high temperature superconducting (HTS) materials having a critical temperature above the boiling point of liquid nitrogen has generated a large amount of interest in both the basic and applied scientific communities. Considerable research effort has been expended in developing HTS microwave devices, since thin film, passive, microwave components will likely be the first area to be successfully commercialized. This thesis describes a new thin film HTS microwave device that can be operated as a switch or as a continuously variable attenuator. It is well suited for low power analog signal control applications and can easily be integrated with other HTS devices. Due to its small size and mass, the device is expected to find application as a receiver protection switch or as an automatic gain control element, both used in satellite communications receivers. The device has a very low insertion loss, and the isolation in the OFF state is continuously variable to 25 dB. With minor modifications, an isolation exceeding 50 dB is readily achievable. A patent application for the device has been filed, with the patent rights assigned to COM DEV. The device is based on an unusual non-linear response in HTS materials. Under a non-zero DC voltage bias, the current through a superconducting bridge is essentially voltage independent. We have proposed a thermal instability to account for this behaviour. Thermal modelling in conjunction with direct temperature measurements were used to confirm the validity of the model. We have developed a detailed model explaining the microwave response of the device. The model accurately predicts the microwave attenuation as a function of the applied DC control voltage and fully explains the device operation. A key feature is that the device acts as a pure resistive element at microwave frequencies, with no reactance. The resistance is continuously variable, controlled by the DC bias voltage. This distinguishes it from a PIN diode, since PIN diodes have a capacitive reactance that limits their frequency range. Measurements made to confirm the microwave model validity resulted in the development of a new cryogenic de-embedding technique. The technique allows accurate microwave measurements to be made on devices at cryogenic temperatures using only room temperature calibration standards. We have also investigated the effect of kinetic inductance on coplanar waveguide transmission lines, and indicate under what conditions kinetic inductance must be considered in transmission line design.

Control of Methane Production and Exchange in Northern Peatlands

NASA Technical Reports Server (NTRS)

Crill, Patrick

1997-01-01

This proposal has successfully supported studies that have developed unique long ten-n datasets of methane (CH4) emissions and carbon dioxide (CO2) exchange in order to quantify the controls on CH4 production and exchange especially the linkages to the carbon cycle in northern peatlands. The primary research site has been a small fen in southeastern New Hampshire where a unique multi-year data baseline of CH4 flux measurements was begun (with NASA funding) in 1989. The fen has also been instrumented for continuous hydrological and meteorological observations and year-round porewater sampling. Multiyear datasets of methane flux are very valuable and very rare. Datasets using the same sampling techniques at the same sites are the only way to assess the effect of the integrated ecosystem response to climatological variability. The research has had two basic objectives: 1. To quantify the effect of seasonal and interannual variability on CH4flux. 2. To examine process level controls on methane dynamics.

Automatic control: the vertebral column of dogfish sharks behaves as a continuously variable transmission with smoothly shifting functions.

PubMed

Porter, Marianne E; Ewoldt, Randy H; Long, John H

2016-09-15

During swimming in dogfish sharks, Squalus acanthias, both the intervertebral joints and the vertebral centra undergo significant strain. To investigate this system, unique among vertebrates, we cyclically bent isolated segments of 10 vertebrae and nine joints. For the first time in the biomechanics of fish vertebral columns, we simultaneously characterized non-linear elasticity and viscosity throughout the bending oscillation, extending recently proposed techniques for large-amplitude oscillatory shear (LAOS) characterization to large-amplitude oscillatory bending (LAOB). The vertebral column segments behave as non-linear viscoelastic springs. Elastic properties dominate for all frequencies and curvatures tested, increasing as either variable increases. Non-linearities within a bending cycle are most in evidence at the highest frequency, 2.0 Hz, and curvature, 5 m -1 Viscous bending properties are greatest at low frequencies and high curvatures, with non-linear effects occurring at all frequencies and curvatures. The range of mechanical behaviors includes that of springs and brakes, with smooth transitions between them that allow for continuously variable power transmission by the vertebral column to assist in the mechanics of undulatory propulsion. © 2016. Published by The Company of Biologists Ltd.

Solar powered actuator with continuously variable auxiliary power control

NASA Technical Reports Server (NTRS)

Nola, F. J. (Inventor)

1984-01-01

A solar powered system is disclosed in which a load such as a compressor is driven by a main induction motor powered by a solar array. An auxiliary motor shares the load with the solar powered motor in proportion to the amount of sunlight available, is provided with a power factor controller for controlling voltage applied to the auxiliary motor in accordance with the loading on that motor. In one embodiment, when sufficient power is available from the solar cell, the auxiliary motor is driven as a generator by excess power from the main motor so as to return electrical energy to the power company utility lines.

Cells, embryos and development in space

NASA Technical Reports Server (NTRS)

Krikorian, A. D.

1984-01-01

Work continues to focus on the demonstrable totipotency of cultured somatic cells of various higher plants and has examined the conditions which regulate this propensity to be controllably released. This was done with special reference to cells obtained from cultured explants of daylily and carrot. For purposes of identifying the variables in question, work was carried out almost exclusively in liquid media. The events that intervene between the aseptic isolation of tissue explants, the culture of small derived units and free cells and the propagation in large numbers of adventive or somatic embryos to plantlets were traced and certain definitive stages at which control is exercised were identified. In daylily, morphologically competent units are now propagated with a high degree of precision in rotated liquid cultures in bulk, and under the conditions of continuous neutralized gravity, the development progresses so that embryo-plantlets are obtained.

A non-linear data mining parameter selection algorithm for continuous variables

PubMed Central

Razavi, Marianne; Brady, Sean

2017-01-01

In this article, we propose a new data mining algorithm, by which one can both capture the non-linearity in data and also find the best subset model. To produce an enhanced subset of the original variables, a preferred selection method should have the potential of adding a supplementary level of regression analysis that would capture complex relationships in the data via mathematical transformation of the predictors and exploration of synergistic effects of combined variables. The method that we present here has the potential to produce an optimal subset of variables, rendering the overall process of model selection more efficient. This algorithm introduces interpretable parameters by transforming the original inputs and also a faithful fit to the data. The core objective of this paper is to introduce a new estimation technique for the classical least square regression framework. This new automatic variable transformation and model selection method could offer an optimal and stable model that minimizes the mean square error and variability, while combining all possible subset selection methodology with the inclusion variable transformations and interactions. Moreover, this method controls multicollinearity, leading to an optimal set of explanatory variables. PMID:29131829

Method and apparatus for manufacturing gas tags

DOEpatents

Gross, K.C.; Laug, M.T.

1996-12-17

For use in the manufacture of gas tags employed in a gas tagging failure detection system for a nuclear reactor, a plurality of commercial feed gases each having a respective noble gas isotopic composition are blended under computer control to provide various tag gas mixtures having selected isotopic ratios which are optimized for specified defined conditions such as cost. Using a new approach employing a discrete variable structure rather than the known continuous-variable optimization problem, the computer controlled gas tag manufacturing process employs an analytical formalism from condensed matter physics known as stochastic relaxation, which is a special case of simulated annealing, for input feed gas selection. For a tag blending process involving M tag isotopes with N distinct feed gas mixtures commercially available from an enriched gas supplier, the manufacturing process calculates the cost difference between multiple combinations and specifies gas mixtures which approach the optimum defined conditions. The manufacturing process is then used to control tag blending apparatus incorporating tag gas canisters connected by stainless-steel tubing with computer controlled valves, with the canisters automatically filled with metered quantities of the required feed gases. 4 figs.

Method and apparatus for manufacturing gas tags

DOEpatents

Gross, Kenny C.; Laug, Matthew T.

1996-01-01

For use in the manufacture of gas tags employed in a gas tagging failure detection system for a nuclear reactor, a plurality of commercial feed gases each having a respective noble gas isotopic composition are blended under computer control to provide various tag gas mixtures having selected isotopic ratios which are optimized for specified defined conditions such as cost. Using a new approach employing a discrete variable structure rather than the known continuous-variable optimization problem, the computer controlled gas tag manufacturing process employs an analytical formalism from condensed matter physics known as stochastic relaxation, which is a special case of simulated annealing, for input feed gas selection. For a tag blending process involving M tag isotopes with N distinct feed gas mixtures commercially available from an enriched gas supplier, the manufacturing process calculates the cost difference between multiple combinations and specifies gas mixtures which approach the optimum defined conditions. The manufacturing process is then used to control tag blending apparatus incorporating tag gas canisters connected by stainless-steel tubing with computer controlled valves, with the canisters automatically filled with metered quantities of the required feed gases.

Testing quantum contextuality of continuous-variable states

DOE Office of Scientific and Technical Information (OSTI.GOV)

McKeown, Gerard; Paternostro, Mauro; Paris, Matteo G. A.

2011-06-15

We investigate the violation of noncontextuality by a class of continuous-variable states, including variations of entangled coherent states and a two-mode continuous superposition of coherent states. We generalize the Kochen-Specker (KS) inequality discussed by Cabello [A. Cabello, Phys. Rev. Lett. 101, 210401 (2008)] by using effective bidimensional observables implemented through physical operations acting on continuous-variable states, in a way similar to an approach to the falsification of Bell-Clauser-Horne-Shimony-Holt inequalities put forward recently. We test for state-independent violation of KS inequalities under variable degrees of state entanglement and mixedness. We then demonstrate theoretically the violation of a KS inequality for anymore » two-mode state by using pseudospin observables and a generalized quasiprobability function.« less

Comparison of the trunk-pelvis and lower extremities sagittal plane inter-segmental coordination and variability during walking in persons with and without chronic low back pain.

PubMed

Ebrahimi, Samaneh; Kamali, Fahimeh; Razeghi, Mohsen; Haghpanah, Seyyed Arash

2017-04-01

Inter-segmental coordination can be influenced by chronic low back pain (CLBP). The sagittal plane lower extremities inter-segmental coordination pattern and variability, in conjunction with the pelvis and trunk, were assessed in subjects with and without non-specific CLBP during free-speed walking. Kinematic data were collected from 10 non-specific CLBP and 10 non-CLBP control volunteers while the subjects were walking at their preferred speed. Sagittal plane time-normalized segmental angles and velocities were used to calculate continuous relative phase for each data point. Mean absolute relative phase (MARP) and deviation phase (DP) were derived to quantify the trunk-pelvis and bilateral pelvis-thigh, thigh-shank and shank-foot coordination pattern and variability over the stance and swing phases of gait. Mann-Whitney U test was employed to compare the means of DP and MARP values between two groups (same side comparison). Statistical analysis revealed more in-phase/less variable trunk-pelvis coordination in the CLBP group (P<0.05). CLBP group demonstrated less variable right or left pelvis-thigh coordination pattern (P<0.05). Moreover, the left thigh-shank and left shank-foot MARP values in the CLBP group, were more in-phase than left MARP values in the non-CLBP control group during the swing phase (P<0.05). In conclusion, the sagittal plane lower extremities, pelvis and trunk coordination pattern and variability could be generally affected by CLBP during walking. These changes can be possible compensatory strategies of the motor control system which can be considered in the CLBP subjects. Copyright © 2017 Elsevier B.V. All rights reserved.

CAN'T MISS--conquer any number task by making important statistics simple. Part 1. Types of variables, mean, median, variance, and standard deviation.

PubMed

Hansen, John P

2003-01-01

Healthcare quality improvement professionals need to understand and use inferential statistics to interpret sample data from their organizations. In quality improvement and healthcare research studies all the data from a population often are not available, so investigators take samples and make inferences about the population by using inferential statistics. This three-part series will give readers an understanding of the concepts of inferential statistics as well as the specific tools for calculating confidence intervals for samples of data. This article, Part 1, presents basic information about data including a classification system that describes the four major types of variables: continuous quantitative variable, discrete quantitative variable, ordinal categorical variable (including the binomial variable), and nominal categorical variable. A histogram is a graph that displays the frequency distribution for a continuous variable. The article also demonstrates how to calculate the mean, median, standard deviation, and variance for a continuous variable.

Electrophysiological assessment of water stress in fruit-bearing woody plants.

PubMed

Ríos-Rojas, Liliana; Tapia, Franco; Gurovich, Luis A

2014-06-15

Development and evaluation of a real-time plant water stress sensor, based on the electrophysiological behavior of fruit-bearing woody plants is presented. Continuous electric potentials are measured in tree trunks for different irrigation schedules, inducing variable water stress conditions; results are discussed in relation to soil water content and micro-atmospheric evaporative demand, determined continuously by conventional sensors, correlating this information with tree electric potential measurements. Systematic and differentiable patterns of electric potentials for water-stressed and no-stressed trees in 2 fruit species are presented. Early detection and recovery dynamics of water stress conditions can also be monitored with these electrophysiology sensors, which enable continuous and non-destructive measurements for efficient irrigation scheduling throughout the year. The experiment is developed under controlled conditions, in Faraday cages located at a greenhouse area, both in Persea americana and Prunus domestica plants. Soil moisture evolution is controlled using capacitance sensors and solar radiation, temperature, relative humidity, wind intensity and direction are continuously registered with accurate weather sensors, in a micro-agrometeorological automatic station located at the experimental site. The electrophysiological sensor has two stainless steel electrodes (measuring/reference), inserted on the stem; a high precision Keithley 2701 digital multimeter is used to measure plant electrical signals; an algorithm written in MatLab(®), allows correlating the signal to environmental variables. An electric cyclic behavior is observed (circadian cycle) in the experimental plants. For non-irrigated plants, the electrical signal shows a time positive slope and then, a negative slope after restarting irrigation throughout a rather extended recovery process, before reaching a stable electrical signal with zero slope. Well-watered plants presented a continuous signal with daily maximum and a minimum EP of similar magnitude in time, with zero slope. This plant electrical behavior is proposed for the development of a sensor measuring real-time plant water status. Copyright © 2014 Elsevier GmbH. All rights reserved.

Virtual continuity of measurable functions and its applications

NASA Astrophysics Data System (ADS)

Vershik, A. M.; Zatitskii, P. B.; Petrov, F. V.

2014-12-01

A classical theorem of Luzin states that a measurable function of one real variable is `almost' continuous. For measurable functions of several variables the analogous statement (continuity on a product of sets having almost full measure) does not hold in general. The search for a correct analogue of Luzin's theorem leads to a notion of virtually continuous functions of several variables. This apparently new notion implicitly appears in the statements of embedding theorems and trace theorems for Sobolev spaces. In fact it reveals the nature of such theorems as statements about virtual continuity. The authors' results imply that under the conditions of Sobolev theorems there is a well-defined integration of a function with respect to a wide class of singular measures, including measures concentrated on submanifolds. The notion of virtual continuity is also used for the classification of measurable functions of several variables and in some questions on dynamical systems, the theory of polymorphisms, and bistochastic measures. In this paper the necessary definitions and properties of admissible metrics are recalled, several definitions of virtual continuity are given, and some applications are discussed. Bibliography: 24 titles.

Continuous and difficult discrete cognitive tasks promote improved stability in older adults.

PubMed

Lajoie, Yves; Jehu, Deborah A; Richer, Natalie; Chan, Alan

2017-06-01

Directing attention away from postural control and onto a cognitive task affords the emergence of automatic control processes. Perhaps the continuous withdrawal of attention from the postural task facilitates an automatization of posture as opposed to only intermittent withdrawal; however this is unknown in the aging population. Twenty older adults (69.9±3.5years) stood with feet together on a force platform for 60s while performing randomly assigned discrete and continuous cognitive tasks. Participants were instructed to stand comfortably with their arms by their sides while verbally responding to the auditory stimuli as fast as possible during the discrete tasks, or mentally performing the continuous cognitive tasks. Participants also performed single-task standing. Results demonstrate significant reductions in sway amplitude and sway variability for the difficult discrete task as well as the continuous tasks relative to single-task standing. The continuous cognitive tasks also prompted greater frequency of sway in the anterior-posterior direction compared to single-standing and discrete tasks, and greater velocity in both directions compared to single-task standing, which could suggest ankle stiffening. No differences in the simple discrete condition were shown compared to single-task standing, perhaps due to the simplicity of the task. Therefore, we propose that the level of difficulty of the task, the specific neuropsychological process engaged during the cognitive task, and the type of task (discrete vs. continuous) influence postural control in older adults. Dual-tasking is a common activity of daily living; this work provides insight into the age-related changes in postural stability and attention demand. Copyright © 2017 Elsevier B.V. All rights reserved.

Chronic baroreflex activation restores spontaneous baroreflex control and variability of heart rate in obesity-induced hypertension

PubMed Central

Iliescu, Radu; Tudorancea, Ionut; Irwin, Eric D.

2013-01-01

The sensitivity of baroreflex control of heart rate is depressed in subjects with obesity hypertension, which increases the risk for cardiac arrhythmias. The mechanisms are not fully known, and there are no therapies to improve this dysfunction. To determine the cardiovascular dynamic effects of progressive increases in body weight leading to obesity and hypertension in dogs fed a high-fat diet, 24-h continuous recordings of spontaneous fluctuations in blood pressure and heart rate were analyzed in the time and frequency domains. Furthermore, we investigated whether autonomic mechanisms stimulated by chronic baroreflex activation and renal denervation—current therapies in patients with resistant hypertension, who are commonly obese—restore cardiovascular dynamic control. Increases in body weight to ∼150% of control led to a gradual increase in mean arterial pressure to 17 ± 3 mmHg above control (100 ± 2 mmHg) after 4 wk on the high-fat diet. In contrast to the gradual increase in arterial pressure, tachycardia, attenuated chronotropic baroreflex responses, and reduced heart rate variability were manifest within 1–4 days on high-fat intake, reaching 130 ± 4 beats per minute (bpm) (control = 86 ± 3 bpm) and ∼45% and <20%, respectively, of control levels. Subsequently, both baroreflex activation and renal denervation abolished the hypertension. However, only baroreflex activation effectively attenuated the tachycardia and restored cardiac baroreflex sensitivity and heart rate variability. These findings suggest that baroreflex activation therapy may reduce the risk factors for cardiac arrhythmias as well as lower arterial pressure. PMID:23913707

Use of research-based instructional strategies in introductory physics: Where do faculty leave the innovation-decision process?

NASA Astrophysics Data System (ADS)

Henderson, Charles; Dancy, Melissa; Niewiadomska-Bugaj, Magdalena

2012-12-01

During the fall of 2008 a web survey, designed to collect information about pedagogical knowledge and practices, was completed by a representative sample of 722 physics faculty across the United States (50.3% response rate). This paper presents partial results to describe how 20 potential predictor variables correlate with faculty knowledge about and use of research-based instructional strategies (RBIS). The innovation-decision process was conceived of in terms of four stages: knowledge versus no knowledge, trial versus no trial, continuation versus discontinuation, and high versus low use. The largest losses occur at the continuation stage, with approximately 1/3 of faculty discontinuing use of all RBIS after trying one or more of these strategies. Nine of the predictor variables were statistically significant for at least one of these stages when controlling for other variables. Knowledge and/or use of RBIS are significantly correlated with reading teaching-related journals, attending talks and workshops related to teaching, attending the physics and astronomy new faculty workshop, having an interest in using more RBIS, being female, being satisfied with meeting instructional goals, and having a permanent, full-time position. The types of variables that are significant at each stage vary substantially. These results suggest that common dissemination strategies are good at creating knowledge about RBIS and motivation to try a RBIS, but more work is needed to support faculty during implementation and continued use of RBIS. Also, contrary to common assumptions, faculty age, institutional type, and percentage of job related to teaching were not found to be barriers to knowledge or use at any stage. High research productivity and large class sizes were not found to be barriers to use of at least some RBIS.

Monkeys time their pauses of movement and not their movement-kinematics during a synchronization-continuation rhythmic task.

PubMed

Donnet, Sophie; Bartolo, Ramon; Fernandes, José Maria; Cunha, João Paulo Silva; Prado, Luis; Merchant, Hugo

2014-05-01

A critical question in tapping behavior is to understand whether the temporal control is exerted on the duration and trajectory of the downward-upward hand movement or on the pause between hand movements. In the present study, we determined the duration of both the movement execution and pauses of monkeys performing a synchronization-continuation task (SCT), using the speed profile of their tapping behavior. We found a linear increase in the variance of pause-duration as a function of interval, while the variance of the motor implementation was relatively constant across intervals. In fact, 96% of the variability of the duration of a complete tapping cycle (pause + movement) was due to the variability of the pause duration. In addition, we performed a Bayesian model selection to determine the effect of interval duration (450-1,000 ms), serial-order (1-6 produced intervals), task phase (sensory cued or internally driven), and marker modality (auditory or visual) on the duration of the movement-pause and tapping movement. The results showed that the most important parameter used to successfully perform the SCT was the control of the pause duration. We also found that the kinematics of the tapping movements was concordant with a stereotyped ballistic control of the hand pressing the push-button. The present findings support the idea that monkeys used an explicit timing strategy to perform the SCT, where a dedicated timing mechanism controlled the duration of the pauses of movement, while also triggered the execution of fixed movements across each interval of the rhythmic sequence. Copyright © 2014 the American Physiological Society.

Design and Methods of a Randomized Trial of Continuous Glucose Monitoring in Persons With Type 1 Diabetes With Impaired Glycemic Control Treated With Multiple Daily Insulin Injections (GOLD Study).

PubMed

Lind, Marcus; Polonsky, William; Hirsch, Irl B; Heise, Tim; Bolinder, Jan; Dahlqvist, Sofia; Pehrsson, Nils-Gunnar; Moström, Peter

2016-05-01

The majority of individuals with type 1 diabetes today have glucose levels exceeding guidelines. The primary aim of this study was to evaluate whether continuous glucose monitoring (CGM), using the Dexcom G4 stand-alone system, improves glycemic control in adults with type 1 diabetes treated with multiple daily insulin injections (MDI). Individuals with type 1 diabetes and inadequate glycemic control (HbA1c ≥ 7.5% = 58 mmol/mol) treated with MDI were randomized in a cross-over design to the Dexcom G4 versus conventional care for 6 months followed by a 4-month wash-out period. Masked CGM was performed before randomization, during conventional treatment, and during the wash-out period to evaluate effects on hypoglycemia, hyperglycemia, and glycemic variability. Questionnaires were used to evaluate diabetes treatment satisfaction, fear of hypoglycemia, hypoglycemia confidence, diabetes-related distress, overall well-being, and physical activity during the different phases of the trial. The primary endpoint was the difference in HbA1c at the end of each treatment phase. A total of 205 patients were screened, of whom 161 were randomized between February and December 2014. Study completion is anticipated in April 2016. It is expected that the results of this study will establish whether using the Dexcom G4 stand-alone system in individuals with type 1 diabetes treated with MDI improves glycemic control, reduces hypoglycemia, and influences quality-of-life indicators and glycemic variability. © 2016 Diabetes Technology Society.

Development of an Integrated Nonlinear Aeroservoelastic Flight Dynamic Model of the NASA Generic Transport Model

NASA Technical Reports Server (NTRS)

Nguyen, Nhan; Ting, Eric

2018-01-01

This paper describes a recent development of an integrated fully coupled aeroservoelastic flight dynamic model of the NASA Generic Transport Model (GTM). The integrated model couples nonlinear flight dynamics to a nonlinear aeroelastic model of the GTM. The nonlinearity includes the coupling of the rigid-body aircraft states in the partial derivatives of the aeroelastic angle of attack. Aeroservoelastic modeling of the control surfaces which are modeled by the Variable Camber Continuous Trailing Edge Flap is also conducted. The R.T. Jones' method is implemented to approximate unsteady aerodynamics. Simulations of the GTM are conducted with simulated continuous and discrete gust loads..

A FORTRAN program for the analysis of linear continuous and sample-data systems

NASA Technical Reports Server (NTRS)

Edwards, J. W.

1976-01-01

A FORTRAN digital computer program which performs the general analysis of linearized control systems is described. State variable techniques are used to analyze continuous, discrete, and sampled data systems. Analysis options include the calculation of system eigenvalues, transfer functions, root loci, root contours, frequency responses, power spectra, and transient responses for open- and closed-loop systems. A flexible data input format allows the user to define systems in a variety of representations. Data may be entered by inputing explicit data matrices or matrices constructed in user written subroutines, by specifying transfer function block diagrams, or by using a combination of these methods.

Initial Assessment of a Variable-Camber Continuous Trailing-Edge Flap System on a Rigid Wing for Drag Reduction in Subsonic Cruise

NASA Technical Reports Server (NTRS)

Ippolito, Corey; Nguyen, Nhan; Totah, Joe; Trinh, Khanh; Ting, Eric

2013-01-01

In this paper, we describe an initial optimization study of a Variable-Camber Continuous Trailing-Edge Flap (VCCTEF) system. The VCCTEF provides a light-weight control system for aircraft with long flexible wings, providing efficient high-lift capability for takeoff and landing, and greater efficiency with reduced drag at cruising flight by considering the effects of aeroelastic wing deformations in the control law. The VCCTEF system is comprised of a large number of distributed and individually-actuatable control surfaces that are constrained in movement relative to neighboring surfaces, and are non-trivially coupled through structural aeroelastic dynamics. Minimzation of drag results in a constrained, coupled, non-linear optimization over a high-dimension search space. In this paper, we describe the modeling, analysis, and optimization of the VCCTEF system control inputs for minimum drag in cruise. The purpose of this initial study is to quantify the expected benefits of the system concept. The scope of this analysis is limited to consideration of a rigid wing without structural flexibility in a steady-state cruise condition at various fuel weights. For analysis, we developed an optimization engine that couples geometric synthesis with vortex-lattice analysis to automate the optimization procedure. In this paper, we present and describe the VCCTEF system concept, optimization approach and tools, run-time performance, and results of the optimization at 20%, 50%, and 80% fuel load. This initial limited-scope study finds the VCCTEF system can potentially gain nearly 10% reduction in cruise drag, provides greater drag savings at lower operating weight, and efficiency is negatively impacted by the severity of relative constraints between control surfaces.

Properties of Rolled AZ31 Magnesium Alloy Sheet Fabricated by Continuous Variable Cross-Section Direct Extrusion

NASA Astrophysics Data System (ADS)

Liu, Yang; Li, Feng; Li, Xue Wen; Shi, Wen Yong

2018-03-01

Rolling is currently a widely used method for manufacturing and processing high-performance magnesium alloy sheets and has received widespread attention in recent years. Here, we combined continuous variable cross-section direct extrusion (CVCDE) and rolling processes. The microstructure and mechanical properties of the resulting sheets rolled at different temperatures from CVCDE extrudate were investigated by optical microscopy, scanning electron microscope, transmission electron microscopy and electron backscatter diffraction. The results showed that a fine-grained microstructure was present with an average grain size of 3.62 μm in sheets rolled from CVCDE extrudate at 623 K. Dynamic recrystallization and a large strain were induced by the multi-pass rolling, which resulted in grain refinement. In the 573-673 K range, the yield strength, tensile strength and elongation initially increased and then declined as the CVCDE temperature increased. The above results provide an important scientific basis of processing, manufacturing and the active control on microstructure and property for high-performance magnesium alloy sheet.

A sequential learning analysis of decisions in organizations to escalate investments despite continuing costs or losses

PubMed Central

Goltz, Sonia M.

1992-01-01

Reinforcement process may underlie decisions frequently found in organizations to escalate investments of time, money and other resources in strategies (e.g., product development, capital investment, plant expansion) that do not result in immediate reinforces. Whereas cognitive biases have been proffered in previous explanations, the present analysis suggested that this persistence is a form of resistance to extinction arising from experiences with past investments that were variably reinforced. This explanation was examined in two experiments by varying the pattern of returns and losses subjects experienced for investment decisions prior to experiencing a series losses. Consistent with the proposed explanation, two conditions resulted in higher levels of recommitment during continuous losses: (a) training using a variable schedule of partial reinforcement, and (b) no training on the task. Results indicate that behavior analysis can be used to understand and control situations in organizations that are prone to escalation, such as investments in the research and development of new product lines and extensions of further loans to customers. PMID:16795785

Adaptive control of base-isolated buildings using piezoelectric friction dampers against near-field earthquakes

NASA Astrophysics Data System (ADS)

Bitaraf, Maryam; Ozbulut, Osman E.; Hurlebaus, Stefan

2010-04-01

This paper investigates the effectiveness of two adaptive control strategies for modulating control force of piezoelectric friction dampers (PFDs) that are employed as semi-active devices in combination with laminated rubber bearings for seismic protection of buildings. The first controller developed in this study is a direct adaptive fuzzy logic controller. It consists of an upper-level and a sub-level direct fuzzy controller. In the hierarchical control scheme, higher-level controller modifies universe of discourse of both premise and consequent variables of the sub-level controller using scaling factors in order to determine command voltage of the damper according to current level of ground motion. The sub-level fuzzy controller employs isolation displacement and velocity as its premise variables and command voltage as its consequent variable. The second controller is based on the simple adaptive control (SAC) method, which is a type of direct adaptive control approach. The objective of the SAC method is to make the plant, the controlled system, track the behavior of the structure with the optimum performance. By using SAC strategy, any change in the characteristics of the structure or uncertainties in the modeling of the structure and in the external excitation would be considered because it continuously monitors its own performance to modify its parameters. Here, SAC methodology is employed to obtain the required force which results in the optimum performance of the structure. Then, the command voltage of the PFD is determined to generate the desired force. For comparison purposes, an optimal controller is also developed and considered in the simulations together with maximum passive operation of the friction damper. Time-history analyses of a base-isolated five-story building are performed to evaluate the performance of the controllers. Results reveal that developed adaptive controllers can successfully improve seismic response of the base-isolated buildings against various types of earthquakes.

A Bayesian Semiparametric Latent Variable Model for Mixed Responses

ERIC Educational Resources Information Center

Fahrmeir, Ludwig; Raach, Alexander

2007-01-01

In this paper we introduce a latent variable model (LVM) for mixed ordinal and continuous responses, where covariate effects on the continuous latent variables are modelled through a flexible semiparametric Gaussian regression model. We extend existing LVMs with the usual linear covariate effects by including nonparametric components for nonlinear…

Factors Influencing Continuous Breath Signal in Intubated and Mechanically-Ventilated Intensive Care Unit Patients Measured by an Electronic Nose

PubMed Central

Leopold, Jan Hendrik; Abu-Hanna, Ameen; Colombo, Camilla; Sterk, Peter J.; Schultz, Marcus J.; Bos, Lieuwe D. J.

2016-01-01

Introduction: Continuous breath analysis by electronic nose (eNose) technology in the intensive care unit (ICU) may be useful in monitoring (patho) physiological changes. However, the application of breath monitoring in a non-controlled clinical setting introduces noise into the data. We hypothesized that the sensor signal is influenced by: (1) humidity in the side-stream; (2) patient-ventilator disconnections and the nebulization of medication; and (3) changes in ventilator settings and the amount of exhaled CO2. We aimed to explore whether the aforementioned factors introduce noise into the signal, and discuss several approaches to reduce this noise. Methods: Study in mechanically-ventilated ICU patients. Exhaled breath was monitored using a continuous eNose with metal oxide sensors. Linear (mixed) models were used to study hypothesized associations. Results: In total, 1251 h of eNose data were collected. First, the initial 15 min of the signal was discarded. There was a negative association between humidity and Sensor 1 (Fixed-effect β: −0.05 ± 0.002) and a positive association with Sensors 2–4 (Fixed-effect β: 0.12 ± 0.001); the signal was corrected for this noise. Outliers were most likely due to noise and therefore removed. Sensor values were positively associated with end-tidal CO2, tidal volume and the pressure variables. The signal was corrected for changes in these ventilator variables after which the associations disappeared. Conclusion: Variations in humidity, ventilator disconnections, nebulization of medication and changes of ventilator settings indeed influenced exhaled breath signals measured in ventilated patients by continuous eNose analysis. We discussed several approaches to reduce the effects of these noise inducing variables. PMID:27556467

Impact of Postoperative Antibiotic Prophylaxis Duration on Surgical Site Infections in Autologous Breast Reconstruction.

PubMed

Drury, Kerry E; Lanier, Steven T; Khavanin, Nima; Hume, Keith M; Gutowski, Karol A; Thornton, Brian P; Hansen, Nora M; Murphy, Robert X; Fine, Neil A; Kim, John Y S

2016-02-01

Although some surgeons prescribe prolonged postoperative antibiotics after autologous breast reconstruction, evidence is lacking to support this practice. We used the Tracking Operations and Outcomes for Plastic Surgeons database to evaluate the association between postoperative antibiotic duration and the rate of surgical site infection (SSI) in autologous breast reconstruction. The intervention of interest for this study was postoperative duration of antibiotic prophylaxis: either discontinued 24 hours after surgery or continued beyond 24 hours. The primary outcome variable of interest for this study was the presence of SSI within 30 days of autologous breast reconstruction. Cohort characteristics and 30-day outcomes were compared using χ² and Fischer exact tests for categorical variables and Student t tests for continuous variables. Multivariate logistic regression was used to control for confounders. A total of 1036 patients met inclusion criteria for our study. Six hundred fifty-nine patients (63.6%) received antibiotics for 24 hours postoperatively, and 377 patients (36.4%) received antibiotics for greater than 24 hours. The rate of SSI did not differ significantly between patients given antibiotics for only 24 hours and those continued on antibiotics beyond the 24-hour postoperative time period (5.01% vs 2.92%, P = 0.109). Furthermore, antibiotic duration was not predictive of SSI in multivariate regression modeling. We did not find a statistically significant difference in the rate of SSI in patients who received 24 hours of postoperative antibiotics compared to those that received antibiotics for greater than 24 hours. These findings held for both purely autologous reconstruction as well as latissimus dorsi reconstruction in conjunction with an implant. Thus, our study does not support continuation of postoperative antibiotics beyond 24 hours after autologous breast reconstruction.

Bio-inspired Optimal Locomotion Reconfigurability of Quadruped Rovers using Central Pattern Generators

NASA Astrophysics Data System (ADS)

Bohra, Murtaza

Legged rovers are often considered as viable solutions for traversing unknown terrain. This work addresses the optimal locomotion reconfigurability of quadruped rovers, which consists of obtaining optimal locomotion modes, and transitioning between them. A 2D sagittal plane rover model is considered based on a domestic cat. Using a Genetic Algorithm, the gait, pose and control variables that minimize torque or maximize speed are found separately. The optimization approach takes into account the elimination of leg impact, while considering the entire variable spectrum. The optimal solutions are consistent with other works on gait optimization, and are similar to gaits found in quadruped animals as well. An online model-free gait planning framework is also implemented, that is based on Central Pattern Generators is implemented. It is used to generate joint and control trajectories for any arbitrarily varying speed profile, and shown to regulate locomotion transition and speed modulation, both endogenously and continuously.

Global Warming and Northern Hemisphere Sea Ice Extent.

PubMed

Vinnikov; Robock; Stouffer; Walsh; Parkinson; Cavalieri; Mitchell; Garrett; Zakharov

1999-12-03

Surface and satellite-based observations show a decrease in Northern Hemisphere sea ice extent during the past 46 years. A comparison of these trends to control and transient integrations (forced by observed greenhouse gases and tropospheric sulfate aerosols) from the Geophysical Fluid Dynamics Laboratory and Hadley Centre climate models reveals that the observed decrease in Northern Hemisphere sea ice extent agrees with the transient simulations, and both trends are much larger than would be expected from natural climate variations. From long-term control runs of climate models, it was found that the probability of the observed trends resulting from natural climate variability, assuming that the models' natural variability is similar to that found in nature, is less than 2 percent for the 1978-98 sea ice trends and less than 0.1 percent for the 1953-98 sea ice trends. Both models used here project continued decreases in sea ice thickness and extent throughout the next century.

Self-Esteem, Locus of Control, and First-Time NCLEX-RN Passage of BSN Students at Historically Black Colleges and Universities.

PubMed

Chavis, Pamella Ivey

Relationships between self-esteem, locus of control (LOC), and first-time passage of National Council Licensure Examination for Registered Nurses (NCLEX-RN®) were examined at baccalaureate nursing programs at two historically black colleges and universities. Shortages continue to exceed demands for RNs prepared at the baccalaureate level. Inconsistent pass rates on the NCLEX-RN for graduates of historically black colleges and universities impede the supply of RNs. Surveys and archival data were used to examine characteristics of the sample and explore relationships among variables. All participants (N = 90) reported high self-esteem and internal LOC. Models suggested that all those with high self-esteem and internal LOC would pass the NCLEX-RN; only 85 percent passed the first time. Statistical analysis revealed a lack of statistical significance between self-esteem, LOC, and first-time passage. Variables not included in the study may have affected first-time passage.

Aerobiology and Its Role in the Transmission of Infectious Diseases

PubMed Central

Fernstrom, Aaron; Goldblatt, Michael

2013-01-01

Aerobiology plays a fundamental role in the transmission of infectious diseases. As infectious disease and infection control practitioners continue employing contemporary techniques (e.g., computational fluid dynamics to study particle flow, polymerase chain reaction methodologies to quantify particle concentrations in various settings, and epidemiology to track the spread of disease), the central variables affecting the airborne transmission of pathogens are becoming better known. This paper reviews many of these aerobiological variables (e.g., particle size, particle type, the duration that particles can remain airborne, the distance that particles can travel, and meteorological and environmental factors), as well as the common origins of these infectious particles. We then review several real-world settings with known difficulties controlling the airborne transmission of infectious particles (e.g., office buildings, healthcare facilities, and commercial airplanes), while detailing the respective measures each of these industries is undertaking in its effort to ameliorate the transmission of airborne infectious diseases. PMID:23365758

Satellite NO 2 retrievals suggest China has exceeded its NO x reduction goals from the twelfth Five-Year Plan

DOE PAGES

de Foy, Benjamin; Lu, Zifeng; Streets, David G.

2016-10-27

China’s twelfth Five-Year Plan included pollution control measures with a goal of reducing national emissions of nitrogen oxides (NO x) by 10% by 2015 compared with 2010. Multiple linear regression analysis was used on 11-year time series of all nitrogen dioxide (NO 2) pixels from the Ozone Monitoring Instrument (OMI) over 18 NO 2 hotspots in China. The regression analysis accounted for variations in meteorology, pixel resolution, seasonal effects, weekday variability and year-to-year variability. The NO 2 trends suggested that there was an increase in NO 2 columns in most areas from 2005 to around 2011 which was followed bymore » a strong decrease continuing through 2015. The satellite results were in good agreement with the annual official NO x emission inventories which were available up until 2014. We show the value of evaluating trends in emission inventories using satellite retrievals. It further shows that recent control strategies were effective in reducing emissions and that recent economic transformations in China may be having an effect on NO 2 columns. The satellite information for 2015 suggests that emissions have continued to decrease since the latest inventories available and have surpassed the goals of the twelfth Five-Year Plan.« less

Robust discovery of genetic associations incorporating gene-environment interaction and independence.

PubMed

Tchetgen Tchetgen, Eric

2011-03-01

This article considers the detection and evaluation of genetic effects incorporating gene-environment interaction and independence. Whereas ordinary logistic regression cannot exploit the assumption of gene-environment independence, the proposed approach makes explicit use of the independence assumption to improve estimation efficiency. This method, which uses both cases and controls, fits a constrained retrospective regression in which the genetic variant plays the role of the response variable, and the disease indicator and the environmental exposure are the independent variables. The regression model constrains the association of the environmental exposure with the genetic variant among the controls to be null, thus explicitly encoding the gene-environment independence assumption, which yields substantial gain in accuracy in the evaluation of genetic effects. The proposed retrospective regression approach has several advantages. It is easy to implement with standard software, and it readily accounts for multiple environmental exposures of a polytomous or of a continuous nature, while easily incorporating extraneous covariates. Unlike the profile likelihood approach of Chatterjee and Carroll (Biometrika. 2005;92:399-418), the proposed method does not require a model for the association of a polytomous or continuous exposure with the disease outcome, and, therefore, it is agnostic to the functional form of such a model and completely robust to its possible misspecification.

Performance improvement of continuous-variable quantum key distribution with an entangled source in the middle via photon subtraction

NASA Astrophysics Data System (ADS)

Guo, Ying; Liao, Qin; Wang, Yijun; Huang, Duan; Huang, Peng; Zeng, Guihua

2017-03-01

A suitable photon-subtraction operation can be exploited to improve the maximal transmission of continuous-variable quantum key distribution (CVQKD) in point-to-point quantum communication. Unfortunately, the photon-subtraction operation faces solving the improvement transmission problem of practical quantum networks, where the entangled source is located in the third part, which may be controlled by a malicious eavesdropper, instead of in one of the trusted parts, controlled by Alice or Bob. In this paper, we show that a solution can come from using a non-Gaussian operation, in particular, the photon-subtraction operation, which provides a method to enhance the performance of entanglement-based (EB) CVQKD. Photon subtraction not only can lengthen the maximal transmission distance by increasing the signal-to-noise rate but also can be easily implemented with existing technologies. Security analysis shows that CVQKD with an entangled source in the middle (ESIM) from applying photon subtraction can well increase the secure transmission distance in both direct and reverse reconciliations of the EB-CVQKD scheme, even if the entangled source originates from an untrusted part. Moreover, it can defend against the inner-source attack, which is a specific attack by an untrusted entangled source in the framework of ESIM.

Satellite NO 2 retrievals suggest China has exceeded its NO x reduction goals from the twelfth Five-Year Plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

de Foy, Benjamin; Lu, Zifeng; Streets, David G.

China’s twelfth Five-Year Plan included pollution control measures with a goal of reducing national emissions of nitrogen oxides (NO x) by 10% by 2015 compared with 2010. Multiple linear regression analysis was used on 11-year time series of all nitrogen dioxide (NO 2) pixels from the Ozone Monitoring Instrument (OMI) over 18 NO 2 hotspots in China. The regression analysis accounted for variations in meteorology, pixel resolution, seasonal effects, weekday variability and year-to-year variability. The NO 2 trends suggested that there was an increase in NO 2 columns in most areas from 2005 to around 2011 which was followed bymore » a strong decrease continuing through 2015. The satellite results were in good agreement with the annual official NO x emission inventories which were available up until 2014. We show the value of evaluating trends in emission inventories using satellite retrievals. It further shows that recent control strategies were effective in reducing emissions and that recent economic transformations in China may be having an effect on NO 2 columns. The satellite information for 2015 suggests that emissions have continued to decrease since the latest inventories available and have surpassed the goals of the twelfth Five-Year Plan.« less

Integrating Ecosystem Carbon Dynamics into State-and-Transition Simulation Models of Land Use/Land Cover Change

NASA Astrophysics Data System (ADS)

Sleeter, B. M.; Daniel, C.; Frid, L.; Fortin, M. J.

2016-12-01

State-and-transition simulation models (STSMs) provide a general approach for incorporating uncertainty into forecasts of landscape change. Using a Monte Carlo approach, STSMs generate spatially-explicit projections of the state of a landscape based upon probabilistic transitions defined between states. While STSMs are based on the basic principles of Markov chains, they have additional properties that make them applicable to a wide range of questions and types of landscapes. A current limitation of STSMs is that they are only able to track the fate of discrete state variables, such as land use/land cover (LULC) classes. There are some landscape modelling questions, however, for which continuous state variables - for example carbon biomass - are also required. Here we present a new approach for integrating continuous state variables into spatially-explicit STSMs. Specifically we allow any number of continuous state variables to be defined for each spatial cell in our simulations; the value of each continuous variable is then simulated forward in discrete time as a stochastic process based upon defined rates of change between variables. These rates can be defined as a function of the realized states and transitions of each cell in the STSM, thus providing a connection between the continuous variables and the dynamics of the landscape. We demonstrate this new approach by (1) developing a simple IPCC Tier 3 compliant model of ecosystem carbon biomass, where the continuous state variables are defined as terrestrial carbon biomass pools and the rates of change as carbon fluxes between pools, and (2) integrating this carbon model with an existing LULC change model for the state of Hawaii, USA.

Heat recovery system employing a temperature controlled variable speed fan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, W.T.

1986-05-20

A heat recovery system is described for use in recovering heat from an industrial process producing a heated fluid comprising: a source of inlet air; a housing coupled to the source and including a heat exchanger; means for passing the heated fluid through the heat exchanger; the housing including means for moving a variable volume of air adjustable over a continuous range from the source through the heat exchanger; air discharge means communicating with the housing for discharging air which has passed through the heat exchanger; a control system including first temperature sensing means for sensing the discharge temperature ofmore » the discharge air moving through the discharge means and a control circuit coupled to the first temperature sensing means and to the moving means for varying the volume of air moved in response to the sensed discharge temperature to control the temperature of discharge air passing through the discharge means at a first predetermined value; and the control system including second temperature sensing means for sensing the temperature of the source of inlet air and valve means coupled to and controlled by the control circuit to cause liquid to bypass the heat exchanger when the inlet air temperature rises above a second predetermined value.« less

Comparative analysis of the operation efficiency of the continuous and relay control systems of a multi-axle wheeled vehicle suspension

NASA Astrophysics Data System (ADS)

Zhileykin, M. M.; Kotiev, G. O.; Nagatsev, M. V.

2018-02-01

In order to improve the efficiency of the multi-axle wheeled vehicles (MWV) automotive engineers are increasing their cruising speed. One of the promising ways to improve ride comfort of the MWV is the development of the dynamic active suspension systems and control laws for such systems. Here, by the dynamic control systems we mean the systems operating in real time mode and using current (instantaneous) values of the state variables. The aim of the work is to develop the MWV suspension optimal control laws that would reduce vibrations on the driver’s seat at kinematic excitation. The authors have developed the optimal control laws for damping the oscillations of the MWV body. The developed laws allow reduction of the vibrations on the driver’s seat and increase in the maximum speed of the vehicle. The laws are characterized in that they allow generating the control inputs in real time mode. The authors have demonstrated the efficiency of the proposed control laws by means of mathematical simulation of the MWV driving over unpaved road with kinematic excitation. The proposed optimal control laws can be used in the MWV suspension control systems with magnetorheological shock absorbers or controlled hydropneumatic springs. Further evolution of the research line can be the development of the energy-efficient MWV suspension control systems with continuous control input on the vehicle body.

Bayesian analysis of stage-fall-discharge rating curves and their uncertainties

NASA Astrophysics Data System (ADS)

Mansanarez, V.; Le Coz, J.; Renard, B.; Lang, M.; Pierrefeu, G.; Vauchel, P.

2016-09-01

Stage-fall-discharge (SFD) rating curves are traditionally used to compute streamflow records at sites where the energy slope of the flow is variable due to variable backwater effects. We introduce a model with hydraulically interpretable parameters for estimating SFD rating curves and their uncertainties. Conventional power functions for channel and section controls are used. The transition to a backwater-affected channel control is computed based on a continuity condition, solved either analytically or numerically. The practical use of the method is demonstrated with two real twin-gauge stations, the Rhône River at Valence, France, and the Guthusbekken stream at station 0003ṡ0033, Norway. Those stations are typical of a channel control and a section control, respectively, when backwater-unaffected conditions apply. The performance of the method is investigated through sensitivity analysis to prior information on controls and to observations (i.e., available gaugings) for the station of Valence. These analyses suggest that precisely identifying SFD rating curves requires adapted gauging strategy and/or informative priors. The Madeira River, one of the largest tributaries of the Amazon, provides a challenging case typical of large, flat, tropical river networks where bed roughness can also be variable in addition to slope. In this case, the difference in staff gauge reference levels must be estimated as another uncertain parameter of the SFD model. The proposed Bayesian method is a valuable alternative solution to the graphical and empirical techniques still proposed in hydrometry guidance and standards.

Continuing to drive while sleepy: the influence of sleepiness countermeasures, motivation for driving sleepy, and risk perception.

PubMed

Watling, Christopher N; Armstrong, Kerry A; Obst, Patricia L; Smith, Simon S

2014-12-01

Driver sleepiness is a major contributor to road crashes. The current study sought to examine the association between perceptions of effectiveness of six sleepiness countermeasures and their relationship with self-reports of continuing to drive while sleepy among 309 drivers after controlling for the influence of age, sex, motivation for driving sleepy, and risk perception of sleepy driving. The results demonstrate that the variables of age, sex, motivation, and risk perception were significantly associated with self-reports of continuing to drive while sleepy and only one countermeasure was associated with self-reports of continuing to drive while sleepy. Further, it was found that age differences in self-reports of continuing to drive while sleepy was mediated by participants' motivation and risk perception. These findings highlight modifiable factors that could be focused on with interventions that seek to modify drivers' attitudes and behaviours of driving while sleepy. Copyright © 2014 Elsevier Ltd. All rights reserved.

A randomized controlled trial to compare the effects of sulphonylurea gliclazide MR (modified release) and the DPP-4 inhibitor vildagliptin on glycemic variability and control measured by continuous glucose monitoring (CGM) in Brazilian women with type 2 diabetes.

PubMed

Vianna, Andre Gustavo Daher; Lacerda, Claudio Silva; Pechmann, Luciana Muniz; Polesel, Michelle Garcia; Marino, Emerson Cestari; Faria-Neto, Jose Rocha

2018-05-01

This study aims to evaluate whether there is a difference between the effects of vildagliptin and gliclazide MR (modified release) on glycemic variability (GV) in women with type 2 diabetes (T2DM) as evaluated by continuous glucose monitoring (CGM). An open-label, randomized study was conducted in T2DM women on steady-dose metformin monotherapy which were treated with 50 mg vildagliptin twice daily or 60-120 mg of gliclazide MR once daily. CGM and GV indices calculation were performed at baseline and after 24 weeks. In total, 42 patients (age: 61.9 ± 5.9 years, baseline glycated hemoglobin (HbA1c): 7.3 ± 0.56) were selected and 37 completed the 24-week protocol. Vildagliptin and gliclazide MR reduced GV, as measured by the mean amplitude of glycemic excursions (MAGE, p = 0.007 and 0.034, respectively). The difference between the groups did not reach statistical significance. Vildagliptin also significantly decreased the standard deviation of the mean glucose (SD) and the mean of the daily differences (MODD) (p = 0.007 and 0.030). Vildagliptin and gliclazide MR similarly reduced the MAGE in women with T2DM after 24 weeks of treatment. Further studies are required to attest differences between vildagliptin and gliclazide MR regarding glycemic variability. Copyright © 2018 Elsevier B.V. All rights reserved.

Selenium and breast cancer risk: A prospective nested case-control study on serum selenium levels, smoking habits and overweight.

PubMed

Sandsveden, Malte; Manjer, Jonas

2017-11-01

Previous research has not been conclusive regarding the association between selenium (Se) and breast cancer. This study was conducted to clarify if there is an association between prediagnostic serum Se levels and breast cancer risk. A population based cohort, the Malmö Diet and Cancer Study, was used and linked with the Swedish cancer registry up to 31 December 2013. Our study included 1,186 women with breast cancer and an equal number of controls. Selenium levels were analysed from stored serum samples. The included individuals were divided into quartiles based on Se value and we compared breast cancer cases with controls using logistic regression yielding odds ratios (OR) with 95% confidence intervals. Serum Se was also analysed as a continuous variable regarding breast cancer risk. The analyses were adjusted for established risk factors and stratified on smoking status and body mass index (BMI). When comparing the highest Se quartile with the lowest, the adjusted OR for breast cancer was 0.98 (0.75-1.26). With selenium as a continuous variable the adjusted OR was 1.00 (1.00-1.01) per 10 ng/ml. When comparing the highest with the lowest Se quartile in women with BMI > 25 kg/m 2 the adjusted OR was 0.77 (0.53-1.14). We conclude that it is unlikely that prediagnostic serum selenium is overall associated with breast cancer risk and no modifying effect from BMI or smoking was seen. © 2017 UICC.

Virtual Learning Environment in Continuing Education for Nursing in Oncology: an Experimental Study.

PubMed

das Graças Silva Matsubara, Maria; De Domenico, Edvane Birelo Lopes

2016-12-01

Nurses working in oncology require continuing education and nowadays distance education is a possibility. To compare learning outcomes of the professionals participating in classroom learning versus distance learning; describing the sociodemographic characteristics and digital fluency of participants; comparing learning outcomes with independent variables; assessing the adequacy of educational practices in Virtual Environment Moodle Learning through the constructivist online learning environment survey. An experimental, randomized controlled study; conducted at the A C Camargo Cancer Center, located in São Paulo, SP, Brazil. The study included 97 nurses, with average training of 1 to 2 years. A control group (n = 44) had face to face training and the experiment group (n = 53) had training by distance learning, both with identical program content. The dependent variable was the result of learning, measured by applying a pre-assessment questionnaire and post-intervention for both groups. The sociodemographic and digital fluency data were uniform among the groups. The performance of both groups was statistically significant (p 0.005), and the control group had a greater advantage (40.4 %). Distance education has proven to be an effective alternative for training nurses, especially when they have more complex knowledge, more experience in the area and institutional time. Distance Education may be a possibility for the training of nurses for work in oncology. The association of age, training time and the institution, and the experience in Oncology interfered in the performance of both groups.

Gender-based salary inequity in social work: mediators of gender's effect on salary.

PubMed

Koeske, Gary F; Krowinski, William J

2004-04-01

This study examined the direct effect of gender, controlling for years of experience, job role, and other variables, in a sample of 359 Pennsylvania social workers. Men social workers received significantly more yearly salary (an estimated 3,665 dollars more) than women social workers. A path analysis suggested that the salary advantage for men that was attributable to their acquiring more experience and management positions was slightly larger than the direct effect of gender. The ability of merit variables to explain salary was somewhat greater for men than women. Other variables that mediated the effect of gender on salary were MSW specialization, working in a social work or a related area, and practice area (children and youths, health, mental health, or other area). The results suggest that substantial gender disparity continues to exist in social worker salaries.

Ambulatory ECG and analysis of heart rate variability in Parkinson's disease.

PubMed

Haapaniemi, T H; Pursiainen, V; Korpelainen, J T; Huikuri, H V; Sotaniemi, K A; Myllylä, V V

2001-03-01

Cardiovascular reflex tests have shown both sympathetic and parasympathetic failure in Parkinson's disease. These tests, however, describe the autonomic responses during a restricted time period and have great individual variability, providing a limited view of the autonomic cardiac control mechanisms. Thus, they do not reflect tonic autonomic regulation. The aim was to examine tonic autonomic cardiovascular regulation in untreated patients with Parkinson's disease. 24 Hour ambulatory ECG was recorded in 54 untreated patients with Parkinson's disease and 47 age matched healthy subjects. In addition to the traditional spectral (very low frequency, VLF; low frequency, LF; high frequency, HF) and non-spectral components of heart rate variability, instantaneous beat to beat variability (SD1) and long term continuous variability (SD2) derived from Poincaré plots, and the slope of the power law relation were analysed. All spectral components (p<0.01) and the slope of the power-law relation (p<0.01) were lower in the patients with Parkinson's disease than in the control subjects. The Unified Parkinson's disease rating scale total and motor scores had a negative correlation with VLF and LF power spectrum values and the power law relation slopes. Patients with mild hypokinesia had higher HF values than patients with more severe hypokinesia. Tremor and rigidity were not associated with the HR variability parameters. Parkinson's disease causes dysfunction of the diurnal autonomic cardiovascular regulation as demonstrated by the spectral measures of heart rate variability and the slope of the power law relation. This dysfunction seems to be more profound in patients with more severe Parkinson's disease.

Interval estimation and optimal design for the within-subject coefficient of variation for continuous and binary variables

PubMed Central

Shoukri, Mohamed M; Elkum, Nasser; Walter, Stephen D

2006-01-01

Background In this paper we propose the use of the within-subject coefficient of variation as an index of a measurement's reliability. For continuous variables and based on its maximum likelihood estimation we derive a variance-stabilizing transformation and discuss confidence interval construction within the framework of a one-way random effects model. We investigate sample size requirements for the within-subject coefficient of variation for continuous and binary variables. Methods We investigate the validity of the approximate normal confidence interval by Monte Carlo simulations. In designing a reliability study, a crucial issue is the balance between the number of subjects to be recruited and the number of repeated measurements per subject. We discuss efficiency of estimation and cost considerations for the optimal allocation of the sample resources. The approach is illustrated by an example on Magnetic Resonance Imaging (MRI). We also discuss the issue of sample size estimation for dichotomous responses with two examples. Results For the continuous variable we found that the variance stabilizing transformation improves the asymptotic coverage probabilities on the within-subject coefficient of variation for the continuous variable. The maximum like estimation and sample size estimation based on pre-specified width of confidence interval are novel contribution to the literature for the binary variable. Conclusion Using the sample size formulas, we hope to help clinical epidemiologists and practicing statisticians to efficiently design reliability studies using the within-subject coefficient of variation, whether the variable of interest is continuous or binary. PMID:16686943

Adaptive estimation of hand movement trajectory in an EEG based brain-computer interface system

NASA Astrophysics Data System (ADS)

Robinson, Neethu; Guan, Cuntai; Vinod, A. P.

2015-12-01

Objective. The various parameters that define a hand movement such as its trajectory, speed, etc, are encoded in distinct brain activities. Decoding this information from neurophysiological recordings is a less explored area of brain-computer interface (BCI) research. Applying non-invasive recordings such as electroencephalography (EEG) for decoding makes the problem more challenging, as the encoding is assumed to be deep within the brain and not easily accessible by scalp recordings. Approach. EEG based BCI systems can be developed to identify the neural features underlying movement parameters that can be further utilized to provide a detailed and well defined control command set to a BCI output device. A real-time continuous control is better suited for practical BCI systems, and can be achieved by continuous adaptive reconstruction of movement trajectory than discrete brain activity classifications. In this work, we adaptively reconstruct/estimate the parameters of two-dimensional hand movement trajectory, namely movement speed and position, from multi-channel EEG recordings. The data for analysis is collected by performing an experiment that involved center-out right-hand movement tasks in four different directions at two different speeds in random order. We estimate movement trajectory using a Kalman filter that models the relation between brain activity and recorded parameters based on a set of defined predictors. We propose a method to define these predictor variables that includes spatial, spectral and temporally localized neural information and to select optimally informative variables. Main results. The proposed method yielded correlation of (0.60 ± 0.07) between recorded and estimated data. Further, incorporating the proposed predictor subset selection, the correlation achieved is (0.57 ± 0.07, p {\\lt }0.004) with significant gain in stability of the system, as well as dramatic reduction in number of predictors (76%) for the savings of computational time. Significance. The proposed system provides a real time movement control system using EEG-BCI with control over movement speed and position. These results are higher and statistically significant compared to existing techniques in EEG based systems and thus promise the applicability of the proposed method for efficient estimation of movement parameters and for continuous motor control.

Neural computing for numeric-to-symbolic conversion in control systems

NASA Technical Reports Server (NTRS)

Passino, Kevin M.; Sartori, Michael A.; Antsaklis, Panos J.

1989-01-01

A type of neural network, the multilayer perceptron, is used to classify numeric data and assign appropriate symbols to various classes. This numeric-to-symbolic conversion results in a type of information extraction, which is similar to what is called data reduction in pattern recognition. The use of the neural network as a numeric-to-symbolic converter is introduced, its application in autonomous control is discussed, and several applications are studied. The perceptron is used as a numeric-to-symbolic converter for a discrete-event system controller supervising a continuous variable dynamic system. It is also shown how the perceptron can implement fault trees, which provide useful information (alarms) in a biological system and information for failure diagnosis and control purposes in an aircraft example.

NASA Innovation Fund 2010 Project Elastically Shaped Future Air Vehicle Concept

NASA Technical Reports Server (NTRS)

Nguyen, Nhan

2010-01-01

This report describes a study conducted in 2010 under the NASA Innovation Fund Award to develop innovative future air vehicle concepts. Aerodynamic optimization was performed to produce three different aircraft configuration concepts for low drag, namely drooped wing, inflected wing, and squashed fuselage. A novel wing shaping control concept is introduced. This concept describes a new capability of actively controlling wing shape in-flight to minimize drag. In addition, a novel flight control effector concept is developed to enable wing shaping control. This concept is called a variable camber continuous trailing edge flap that can reduce drag by as much as 50% over a conventional flap. In totality, the potential benefits of fuel savings offered by these concepts can be significant.

A study of the application of singular perturbation theory. [development of a real time algorithm for optimal three dimensional aircraft maneuvers

NASA Technical Reports Server (NTRS)

Mehra, R. K.; Washburn, R. B.; Sajan, S.; Carroll, J. V.

1979-01-01

A hierarchical real time algorithm for optimal three dimensional control of aircraft is described. Systematic methods are developed for real time computation of nonlinear feedback controls by means of singular perturbation theory. The results are applied to a six state, three control variable, point mass model of an F-4 aircraft. Nonlinear feedback laws are presented for computing the optimal control of throttle, bank angle, and angle of attack. Real Time capability is assessed on a TI 9900 microcomputer. The breakdown of the singular perturbation approximation near the terminal point is examined Continuation methods are examined to obtain exact optimal trajectories starting from the singular perturbation solutions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buckdahn, Rainer, E-mail: Rainer.Buckdahn@univ-brest.fr; Li, Juan, E-mail: juanli@sdu.edu.cn; Ma, Jin, E-mail: jinma@usc.edu

In this paper we study the optimal control problem for a class of general mean-field stochastic differential equations, in which the coefficients depend, nonlinearly, on both the state process as well as of its law. In particular, we assume that the control set is a general open set that is not necessary convex, and the coefficients are only continuous on the control variable without any further regularity or convexity. We validate the approach of Peng (SIAM J Control Optim 2(4):966–979, 1990) by considering the second order variational equations and the corresponding second order adjoint process in this setting, and wemore » extend the Stochastic Maximum Principle of Buckdahn et al. (Appl Math Optim 64(2):197–216, 2011) to this general case.« less

General implementation of arbitrary nonlinear quadrature phase gates

NASA Astrophysics Data System (ADS)

Marek, Petr; Filip, Radim; Ogawa, Hisashi; Sakaguchi, Atsushi; Takeda, Shuntaro; Yoshikawa, Jun-ichi; Furusawa, Akira

2018-02-01

We propose general methodology of deterministic single-mode quantum interaction nonlinearly modifying single quadrature variable of a continuous-variable system. The methodology is based on linear coupling of the system to ancillary systems subsequently measured by quadrature detectors. The nonlinear interaction is obtained by using the data from the quadrature detection for dynamical manipulation of the coupling parameters. This measurement-induced methodology enables direct realization of arbitrary nonlinear quadrature interactions without the need to construct them from the lowest-order gates. Such nonlinear interactions are crucial for more practical and efficient manipulation of continuous quadrature variables as well as qubits encoded in continuous-variable systems.

Optimality of Gaussian attacks in continuous-variable quantum cryptography.

PubMed

Navascués, Miguel; Grosshans, Frédéric; Acín, Antonio

2006-11-10

We analyze the asymptotic security of the family of Gaussian modulated quantum key distribution protocols for continuous-variables systems. We prove that the Gaussian unitary attack is optimal for all the considered bounds on the key rate when the first and second momenta of the canonical variables involved are known by the honest parties.

A Primer on Logistic Regression.

ERIC Educational Resources Information Center

Woldbeck, Tanya

This paper introduces logistic regression as a viable alternative when the researcher is faced with variables that are not continuous. If one is to use simple regression, the dependent variable must be measured on a continuous scale. In the behavioral sciences, it may not always be appropriate or possible to have a measured dependent variable on a…

Continuous-variable quantum network coding for coherent states

NASA Astrophysics Data System (ADS)

Shang, Tao; Li, Ke; Liu, Jian-wei

2017-04-01

As far as the spectral characteristic of quantum information is concerned, the existing quantum network coding schemes can be looked on as the discrete-variable quantum network coding schemes. Considering the practical advantage of continuous variables, in this paper, we explore two feasible continuous-variable quantum network coding (CVQNC) schemes. Basic operations and CVQNC schemes are both provided. The first scheme is based on Gaussian cloning and ADD/SUB operators and can transmit two coherent states across with a fidelity of 1/2, while the second scheme utilizes continuous-variable quantum teleportation and can transmit two coherent states perfectly. By encoding classical information on quantum states, quantum network coding schemes can be utilized to transmit classical information. Scheme analysis shows that compared with the discrete-variable paradigms, the proposed CVQNC schemes provide better network throughput from the viewpoint of classical information transmission. By modulating the amplitude and phase quadratures of coherent states with classical characters, the first scheme and the second scheme can transmit 4{log _2}N and 2{log _2}N bits of information by a single network use, respectively.

Understanding DOC Mobilization Dynamics Through High Frequency Measurements in a Headwater Catchment

NASA Astrophysics Data System (ADS)

Werner, B.; Musolff, A.; Lechtenfeld, O.; de Rooij, G. H.; Fleckenstein, J. H.

2017-12-01

Increasing dissolved organic carbon (DOC) exports from headwater catchments impact the quality of downstream waters and pose challenges to water supply. The importance of riparian zones for DOC export from catchments in humid, temperate climates has generally been acknowledged, but the hydrological controls and biogeochemical factors that govern mobilization of DOC from riparian zones remain elusive. By analyzing high-frequency time series of UV-VIS based water quality we therefore aim at a better understanding on temporal dynamics of DOC mobilization and exports. In a first step a one year high frequency (15 minutes) data set from a headwater catchment in the Harz Mountains (Germany) was systematically analyzed for event-based patterns in DOC concentrations. Here, a simplistic linear model was generated to explain DOC concentration level and variability in the stream. Furthermore, spectral (e.g. slopes and SUVA254) and molecular (FT-ICR-MS) characterization of DOC was used to fingerprint in-stream DOC during events. Continuous DOC concentrations were best predicted (R², NSE = 0.53) by instantaneous discharge (Q) and antecede wetness conditions of the last 30 days (AWC30 = Precip.30/PET30) as well as mean air temperature (Tmean30) and mean discharge (Qmean30) of the preceding 30 days. Analyses of 36 events revealed seasonal trends for the slope, intercept and R² of linear log(DOC)-log(Q) regressions that can be best explained by the mean air temperature of the preceding 15 days. Continuously available optical DOC quality parameters SUVA254 and spectral slope (275 nm - 295 nm) systematically changed with shifts in discharge and in DOC concentration. This is underlined by selected FT-ICR-MS measurements indicating higher DOC aromaticity and oxygen content at high flow conditions. The change of DOC quality parameters during events indicate a shift in the activated source zones: DOC with a different quality was mobilized during high flow conditions when higher groundwater levels connected formerly disconnected DOC source zones to the stream. We conclude that the high concentration variability of DOC can be explained by a few controlling variables only. These variables can be linked to event-based DOC source activation and more seasonal controls of DOC production.

Efficacy and safety of regional citrate anticoagulation in critically ill patients undergoing continuous renal replacement therapy.

PubMed

Zhang, Zhongheng; Hongying, Ni

2012-01-01

Regional citrate anticoagulation (RCA) is an attractive anticoagulation mode in continuous renal replacement therapy (CRRT) because it restricts the anticoagulatory effect to the extracorporeal circuit. In recent years, several randomized controlled trials have been conducted to investigate its superiority over other anticoagulation modes. Thus, we performed a systematic review of available evidence on the efficacy and safety of RCA. A systematic review of randomized controlled trials investigating the efficacy and safety of RCA was performed. PubMed, Current Contents, CINAHL, and EMBASE databases were searched to identify relevance articles. Data on circuit life span, bleeding events, metabolic derangement, and mortality were abstracted. Mean difference was used for continuous variables, and risk ratio was used for binomial variables. The random effects or fixed effect model was used to combine these data according to heterogeneity. The software Review Manager 5.1 was used for the meta-analysis. Six studies met our inclusion criteria, which involved a total of 658 circuits. In these six studies patients with liver failure or a high risk of bleeding were excluded. The circuit life span in the RCA group was significantly longer than that in the control group, with a mean difference of 23.03 h (95% CI 0.45-45.61 h). RCA was able to reduce the risk of bleeding, with a risk ratio of 0.28 (95% CI 0.15-0.50). Metabolic stability (electrolyte and acid-base stabilities) in performing RCA was comparable to that in other anticoagulation modes, and metabolic derangements (hypernatremia, metabolic alkalosis, and hypocalcemia) could be easily controlled without significant clinical consequences. Two studies compared mortality rate between RCA and control groups, with one reported similar mortality rate and the other reported superiority of RCA over the control group (hazards ratio 0.7). RCA is effective in maintaining circuit patency and reducing the risk of bleeding, and thus can be recommended for CRRT if and when metabolic monitoring is adequate and the protocol is followed. However, the safety of citrate in patients with liver failure cannot be concluded from current analysis. The metabolic stability can be easily controlled during RCA. Survival benefit from RCA is still controversial due to limited evidence.

Stabilizing laser energy density on a target during pulsed laser deposition of thin films

DOEpatents

Dowden, Paul C.; Jia, Quanxi

2016-05-31

A process for stabilizing laser energy density on a target surface during pulsed laser deposition of thin films controls the focused laser spot on the target. The process involves imaging an image-aperture positioned in the beamline. This eliminates changes in the beam dimensions of the laser. A continuously variable attenuator located in between the output of the laser and the imaged image-aperture adjusts the energy to a desired level by running the laser in a "constant voltage" mode. The process provides reproducibility and controllability for deposition of electronic thin films by pulsed laser deposition.

The whole earth telescope - A new astronomical instrument

NASA Technical Reports Server (NTRS)

Nather, R. E.; Winget, D. E.; Clemens, J. C.; Hansen, C. J.; Hine, B. P.

1990-01-01

A new multimirror ground-based telescope for time-series photometry of rapid variable stars, designed to minimize or eliminate gaps in the brightness record caused by the rotation of the earth, is described. A sequence of existing telescopes distributed in longitude, coordinated from a single control center, is used to measure designated target stars so long as they are in darkness. Data are returned by electronic mail to the control center, where they are analyzed in real time. This instrument is the first to provide data of continuity and quality that permit true high-resolution power spectroscopy of pulsating white dwarf stars.

Mechanisms and kinetics of cellulose fermentation for protein production

NASA Technical Reports Server (NTRS)

Dunlap, C. A.

1971-01-01

The development of a process (and ancillary processing and analytical techniques) to produce bacterial single-cell protein of good nutritional quality from waste cellulose is discussed. A fermentation pilot plant and laboratory were developed and have been in operation for about two years. Single-cell protein (SCP) can be produced from sugarcane bagasse--a typical agricultural cellulosic waste. The optimization and understanding of this process and its controlling variables are examined. Both batch and continuous fermentation runs have been made under controlled conditions in the 535 liter pilot plant vessel and in the laboratory 14-liter fermenters.

Enhancing vehicle cornering limit through sideslip and yaw rate control

NASA Astrophysics Data System (ADS)

Lu, Qian; Gentile, Pierangelo; Tota, Antonio; Sorniotti, Aldo; Gruber, Patrick; Costamagna, Fabio; De Smet, Jasper

2016-06-01

Fully electric vehicles with individually controlled drivetrains can provide a high degree of drivability and vehicle safety, all while increasing the cornering limit and the 'fun-to-drive' aspect. This paper investigates a new approach on how sideslip control can be integrated into a continuously active yaw rate controller to extend the limit of stable vehicle cornering and to allow sustained high values of sideslip angle. The controllability-related limitations of integrated yaw rate and sideslip control, together with its potential benefits, are discussed through the tools of multi-variable feedback control theory and non-linear phase-plane analysis. Two examples of integrated yaw rate and sideslip control systems are presented and their effectiveness is experimentally evaluated and demonstrated on a four-wheel-drive fully electric vehicle prototype. Results show that the integrated control system allows safe operation at the vehicle cornering limit at a specified sideslip angle independent of the tire-road friction conditions.

Linear Modeling and Evaluation of Controls on Flow Response in Western Post-Fire Watersheds

NASA Astrophysics Data System (ADS)

Saxe, S.; Hogue, T. S.; Hay, L.

2015-12-01

This research investigates the impact of wildfires on watershed flow regimes throughout the western United States, specifically focusing on evaluation of fire events within specified subregions and determination of the impact of climate and geophysical variables in post-fire flow response. Fire events were collected through federal and state-level databases and streamflow data were collected from U.S. Geological Survey stream gages. 263 watersheds were identified with at least 10 years of continuous pre-fire daily streamflow records and 5 years of continuous post-fire daily flow records. For each watershed, percent changes in runoff ratio (RO), annual seven day low-flows (7Q2) and annual seven day high-flows (7Q10) were calculated from pre- to post-fire. Numerous independent variables were identified for each watershed and fire event, including topographic, land cover, climate, burn severity, and soils data. The national watersheds were divided into five regions through K-clustering and a lasso linear regression model, applying the Leave-One-Out calibration method, was calculated for each region. Nash-Sutcliffe Efficiency (NSE) was used to determine the accuracy of the resulting models. The regions encompassing the United States along and west of the Rocky Mountains, excluding the coastal watersheds, produced the most accurate linear models. The Pacific coast region models produced poor and inconsistent results, indicating that the regions need to be further subdivided. Presently, RO and HF response variables appear to be more easily modeled than LF. Results of linear regression modeling showed varying importance of watershed and fire event variables, with conflicting correlation between land cover types and soil types by region. The addition of further independent variables and constriction of current variables based on correlation indicators is ongoing and should allow for more accurate linear regression modeling.

Size and distance are perceived independently in an optical tunnel: Evidence for direct perception.

PubMed

Kim, Seokhun; Carello, Claudia; Turvey, Michael T

2016-08-01

The historical but questionable size-distance invariance hypothesis (SDIH) features computation over geometric, oculomotor, and binocular cues and the coupling of percepts-perceived size, S', is mediated by perceived distance, D'. A contemporary non-mediational hypothesis holds that S' and D' are specific to distinct optical variables. We report two experiments with an optical tunnel, an arrangement of alternating black and white concentric rings, that allows systematic manipulation of the optic array at a point of observation while controlling a variety of size and depth cues. Participants viewed targets of different sizes at different distances monocularly, reporting S' and D' via magnitude production. In Experiment 1, the target was either placed in a continuous tunnel (extending 164cm) or in a tunnel that truncated at the target's location. Experiment 2 included a third tunnel, one that was truncated with a flat depiction of the posterior surface structure that would have been visible in the continuous tunnel. In both experiments, S' decreased with D but D' was unaffected by S. Partial correlation analyses showed that the relationship between S' and D' was not significant when the contributions of other variables were removed. Importantly, S' and D' were affected differently by manipulations of the optical tunnel's continuity while computationally obvious visual cues were controlled. These outcomes suggest that D' is not a mediator of S'. Rather S' and D' are independently determined with correlated but different optical bases, results that support the direct model. Copyright © 2016 Elsevier Ltd. All rights reserved.

Controls on morphological variability and role of stream power distribution pattern, Yamuna River, western India

NASA Astrophysics Data System (ADS)

Bawa, Nupur; Jain, Vikrant; Shekhar, Shashank; Kumar, Niraj; Jyani, Vikas

2014-12-01

Understanding the controls on the morphological variability of river systems constitutes one of the fundamental questions in geomorphic investigation. Channel morphology is an important indicator of river processes and is of significance for mapping the hydrology-ecologic connectivity in a river system and for predicting the future trajectory of river health in response to external forcings. This paper documents the spatial morphological variability and its natural and anthropogenic controls for the Yamuna River, a major tributary of the Ganga River, India. The Yamuna River runs through a major urban centre i.e. Delhi National Capital Region. The Yamuna River was divided into eight geomorphically distinct reaches on the basis of the assemblages of geomorphic units and the association of landscape, valley and floodplain settings. The morphological variability was analysed through stream power distribution and sediment load data at various stations. Stream power distribution of the Yamuna River basin is characterised by a non-linear pattern that was used to distinguish (a) high energy ‘natural' upstream reaches, (b) ‘anthropogenically altered', low energy middle stream reaches, and (c) ‘rejuvenated' downstream reaches again with higher stream power. The relationship between stream power and channel morphology in these reaches was integrated with sediment load data to define the maximum flow efficiency (MFE) as the threshold for geomorphic transition. This analysis supports the continuity of river processes and the significance of a holistic, basin-scale approach rather than isolated local scale analysis in river studies.

Movement amplitude on the Functional Re-adaptive Exercise Device: deep spinal muscle activity and movement control.

PubMed

Winnard, A; Debuse, D; Wilkinson, M; Samson, L; Weber, T; Caplan, Nick

2017-08-01

Lumbar multifidus (LM) and transversus abdominis (TrA) show altered motor control, and LM is atrophied, in people with low-back pain (LBP). The Functional Re-adaptive Exercise Device (FRED) involves cyclical lower-limb movement against minimal resistance in an upright posture. It has been shown to recruit LM and TrA automatically, and may have potential as an intervention for non-specific LBP. However, no studies have yet investigated the effects of changes in FRED movement amplitude on the activity of these muscles. This study aimed to assess the effects of different FRED movement amplitudes on LM and TrA muscle thickness and movement variability, to inform an evidence-based exercise prescription. Lumbar multifidus and TrA thickness of eight healthy male volunteers were examined using ultrasound imaging during FRED exercise, normalised to rest at four different movement amplitudes. Movement variability was also measured. Magnitude-based inferences were used to compare each amplitude. Exercise at all amplitudes recruited LM and TrA more than rest, with thickness increases of approximately 5 and 1 mm, respectively. Larger amplitudes also caused increased TrA thickness, LM and TrA muscle thickness variability and movement variability. The data suggests that all amplitudes are useful for recruiting LM and TrA. A progressive training protocol should start in the smallest amplitude, increasing the setting once participants can maintain a consistent movement speed, to continue to challenge the motor control system.

A 1500-year record of climatic and environmental change in Elk Lake, Minnesota I: Varve thickness and gray-scale density

USGS Publications Warehouse

Dean, W.; Anderson, R.; Platt, Bradbury J.; Anderson, D.

2002-01-01

The deepest part (29.5 m) of Elk Lake, Clearwater County, northwestern Minnesota, contains a complete Holocene section that is continuously varved. The varve components are predominantly autochthonous (CaCO3, organic matter, biogenic silica, and several iron and manganese minerals), but the varves do contain a minor detrital-clastic (aluminosilicate) component that is predominantly wind-borne (eolian) and provides an important record of atmospheric conditions. Singular spectrum analysis (SSA) and wavelet analysis of varve thickness recognized significant periodicities in the multicentennial and multidecadal bands that varied in power (i.e., variable significance) and position (i.e., variable period) within the periodic bands. Persistent periodicities of about 10, 22, 40, and 90 years, and, in particular, multicentennial periodicities in varve thickness and other proxy variables are similar to those in spectra of radiocarbon production, a proxy for past solar activity. This suggests that there may be a solar control, perhaps through geomagnetic effects on atmospheric circulation. Multicentennial and multidecadal periodicities also occur in wavelet spectra of relative gray-scale density. However, gray-scale density does not appear to correlate with any of the measured proxy variables, and at this point we do not know what controlled gray scale.

Improving the use of environmental diversity as a surrogate for species representation.

PubMed

Albuquerque, Fabio; Beier, Paul

2018-01-01

The continuous p-median approach to environmental diversity (ED) is a reliable way to identify sites that efficiently represent species. A recently developed maximum dispersion (maxdisp) approach to ED is computationally simpler, does not require the user to reduce environmental space to two dimensions, and performed better than continuous p-median for datasets of South African animals. We tested whether maxdisp performs as well as continuous p-median for 12 datasets that included plants and other continents, and whether particular types of environmental variables produced consistently better models of ED. We selected 12 species inventories and atlases to span a broad range of taxa (plants, birds, mammals, reptiles, and amphibians), spatial extents, and resolutions. For each dataset, we used continuous p-median ED and maxdisp ED in combination with five sets of environmental variables (five combinations of temperature, precipitation, insolation, NDVI, and topographic variables) to select environmentally diverse sites. We used the species accumulation index (SAI) to evaluate the efficiency of ED in representing species for each approach and set of environmental variables. Maxdisp ED represented species better than continuous p-median ED in five of 12 biodiversity datasets, and about the same for the other seven biodiversity datasets. Efficiency of ED also varied with type of variables used to define environmental space, but no particular combination of variables consistently performed best. We conclude that maxdisp ED performs at least as well as continuous p-median ED, and has the advantage of faster and simpler computation. Surprisingly, using all 38 environmental variables was not consistently better than using subsets of variables, nor did any subset emerge as consistently best or worst; further work is needed to identify the best variables to define environmental space. Results can help ecologists and conservationists select sites for species representation and assist in conservation planning.

On discrete control of nonlinear systems with applications to robotics

NASA Technical Reports Server (NTRS)

Eslami, Mansour

1989-01-01

Much progress has been reported in the areas of modeling and control of nonlinear dynamic systems in a continuous-time framework. From implementation point of view, however, it is essential to study these nonlinear systems directly in a discrete setting that is amenable for interfacing with digital computers. But to develop discrete models and discrete controllers for a nonlinear system such as robot is a nontrivial task. Robot is also inherently a variable-inertia dynamic system involving additional complications. Not only the computer-oriented models of these systems must satisfy the usual requirements for such models, but these must also be compatible with the inherent capabilities of computers and must preserve the fundamental physical characteristics of continuous-time systems such as the conservation of energy and/or momentum. Preliminary issues regarding discrete systems in general and discrete models of a typical industrial robot that is developed with full consideration of the principle of conservation of energy are presented. Some research on the pertinent tactile information processing is reviewed. Finally, system control methods and how to integrate these issues in order to complete the task of discrete control of a robot manipulator are also reviewed.

Modeling of feed-forward control using the partial least squares regression method in the tablet compression process.

PubMed

Hattori, Yusuke; Otsuka, Makoto

2017-05-30

In the pharmaceutical industry, the implementation of continuous manufacturing has been widely promoted in lieu of the traditional batch manufacturing approach. More specially, in recent years, the innovative concept of feed-forward control has been introduced in relation to process analytical technology. In the present study, we successfully developed a feed-forward control model for the tablet compression process by integrating data obtained from near-infrared (NIR) spectra and the physical properties of granules. In the pharmaceutical industry, batch manufacturing routinely allows for the preparation of granules with the desired properties through the manual control of process parameters. On the other hand, continuous manufacturing demands the automatic determination of these process parameters. Here, we proposed the development of a control model using the partial least squares regression (PLSR) method. The most significant feature of this method is the use of dataset integrating both the NIR spectra and the physical properties of the granules. Using our model, we determined that the properties of products, such as tablet weight and thickness, need to be included as independent variables in the PLSR analysis in order to predict unknown process parameters. Copyright © 2017 Elsevier B.V. All rights reserved.

Relationship between glycaemic variability and hyperglycaemic clamp-derived functional variables in (impending) type 1 diabetes.

PubMed

Van Dalem, Annelien; Demeester, Simke; Balti, Eric V; Decochez, Katelijn; Weets, Ilse; Vandemeulebroucke, Evy; Van de Velde, Ursule; Walgraeve, An; Seret, Nicole; De Block, Christophe; Ruige, Johannes; Gillard, Pieter; Keymeulen, Bart; Pipeleers, Daniel G; Gorus, Frans K

2015-12-01

We examined whether measures of glycaemic variability (GV), assessed by continuous glucose monitoring (CGM) and self-monitoring of blood glucose (SMBG), can complement or replace measures of beta cell function and insulin action in detecting the progression of preclinical disease to type 1 diabetes. Twenty-two autoantibody-positive (autoAb(+)) first-degree relatives (FDRs) of patients with type 1 diabetes who were themselves at high 5-year risk (50%) for type 1 diabetes underwent CGM, a hyperglycaemic clamp test and OGTT, and were followed for up to 31 months. Clamp variables were used to estimate beta cell function (first-phase [AUC5-10 min] and second-phase [AUC120-150 min] C-peptide release) combined with insulin resistance (glucose disposal rate; M 120-150 min). Age-matched healthy volunteers (n = 20) and individuals with recent-onset type 1 diabetes (n = 9) served as control groups. In autoAb(+) FDRs, M 120-150 min below the 10th percentile (P10) of controls achieved 86% diagnostic efficiency in discriminating between normoglycaemic FDRs and individuals with (impending) dysglycaemia. M 120-150 min outperformed AUC5-10 min and AUC120-150 min C-peptide below P10 of controls, which were only 59-68% effective. Among GV variables, CGM above the reference range was better at detecting (impending) dysglycaemia than elevated SMBG (77-82% vs 73% efficiency). Combined CGM measures were equally efficient as M 120-150 min (86%). Daytime GV variables were inversely correlated with clamp variables, and more strongly with M 120-150 min than with AUC5-10 min or AUC120-150 min C-peptide. CGM-derived GV and the glucose disposal rate, reflecting both insulin secretion and action, outperformed SMBG and first- or second-phase AUC C-peptide in identifying FDRs with (impending) dysglycaemia or diabetes. Our results indicate the feasibility of developing minimally invasive CGM-based criteria for close metabolic monitoring and as outcome measures in trials.

Quantum simulation of quantum field theory using continuous variables

DOE PAGES

Marshall, Kevin; Pooser, Raphael C.; Siopsis, George; ...

2015-12-14

Much progress has been made in the field of quantum computing using continuous variables over the last couple of years. This includes the generation of extremely large entangled cluster states (10,000 modes, in fact) as well as a fault tolerant architecture. This has lead to the point that continuous-variable quantum computing can indeed be thought of as a viable alternative for universal quantum computing. With that in mind, we present a new algorithm for continuous-variable quantum computers which gives an exponential speedup over the best known classical methods. Specifically, this relates to efficiently calculating the scattering amplitudes in scalar bosonicmore » quantum field theory, a problem that is known to be hard using a classical computer. Thus, we give an experimental implementation based on cluster states that is feasible with today's technology.« less

Quantum simulation of quantum field theory using continuous variables

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, Kevin; Pooser, Raphael C.; Siopsis, George

Much progress has been made in the field of quantum computing using continuous variables over the last couple of years. This includes the generation of extremely large entangled cluster states (10,000 modes, in fact) as well as a fault tolerant architecture. This has lead to the point that continuous-variable quantum computing can indeed be thought of as a viable alternative for universal quantum computing. With that in mind, we present a new algorithm for continuous-variable quantum computers which gives an exponential speedup over the best known classical methods. Specifically, this relates to efficiently calculating the scattering amplitudes in scalar bosonicmore » quantum field theory, a problem that is known to be hard using a classical computer. Thus, we give an experimental implementation based on cluster states that is feasible with today's technology.« less

Impact of exercise on diurnal and nocturnal markers of glycaemic variability and oxidative stress in obese individuals with type 2 diabetes or impaired glucose tolerance.

PubMed

Farabi, Sarah S; Carley, David W; Smith, Donald; Quinn, Lauretta

2015-09-01

We measured the effects of a single bout of exercise on diurnal and nocturnal oxidative stress and glycaemic variability in obese subjects with type 2 diabetes mellitus or impaired glucose tolerance versus obese healthy controls. Subjects (in random order) performed either a single 30-min bout of moderate-intensity exercise or remained sedentary for 30 min at two separate visits. To quantify glycaemic variability, standard deviation of glucose (measured by continuous glucose monitoring system) and continuous overlapping net glycaemic action of 1-h intervals (CONGA-1) were calculated for three 12-h intervals during each visit. Oxidative stress was measured by 15-isoprostane F(2t) levels in urine collections for matching 12-h intervals. Exercise reduced daytime glycaemic variability (ΔCONGA-1 = -12.62 ± 5.31 mg/dL, p = 0.04) and urinary isoprostanes (ΔCONGA-1 = -0.26 ± 0.12 ng/mg, p = 0.04) in the type 2 diabetes mellitus/impaired glucose tolerance group. Daytime exercise-induced change in urinary 15-isoprostane F(2t) was significantly correlated with both daytime standard deviation (r = 0.68, p = 0.03) and with subsequent overnight standard deviation (r = 0.73, p = 0.027) in the type 2 diabetes mellitus/impaired glucose tolerance group. Exercise significantly impacts the relationship between diurnal oxidative stress and nocturnal glycaemic variability in individuals with type 2 diabetes mellitus/impaired glucose tolerance. © The Author(s) 2015.

Application of Prognostic Health Management in Digital Electronic Systems

DTIC Science & Technology

2007-01-01

variable external supply applied the necessary core power to the processor while the motherboard continued to source power from the ATX supply. By...isolating the processor power from the motherboard power , control over the aging profile of the processor was achieved. Once nominal operating...Physics-of-failure RISC – Reduced Instruction Set Computer RUL – Remaining Useful Life 1 1-4244-0525-4/07/$20.00 ©2007 IEEE. Paper 1326

A multimodal dataset for various forms of distracted driving

PubMed Central

Taamneh, Salah; Tsiamyrtzis, Panagiotis; Dcosta, Malcolm; Buddharaju, Pradeep; Khatri, Ashik; Manser, Michael; Ferris, Thomas; Wunderlich, Robert; Pavlidis, Ioannis

2017-01-01

We describe a multimodal dataset acquired in a controlled experiment on a driving simulator. The set includes data for n=68 volunteers that drove the same highway under four different conditions: No distraction, cognitive distraction, emotional distraction, and sensorimotor distraction. The experiment closed with a special driving session, where all subjects experienced a startle stimulus in the form of unintended acceleration—half of them under a mixed distraction, and the other half in the absence of a distraction. During the experimental drives key response variables and several explanatory variables were continuously recorded. The response variables included speed, acceleration, brake force, steering, and lane position signals, while the explanatory variables included perinasal electrodermal activity (EDA), palm EDA, heart rate, breathing rate, and facial expression signals; biographical and psychometric covariates as well as eye tracking data were also obtained. This dataset enables research into driving behaviors under neatly abstracted distracting stressors, which account for many car crashes. The set can also be used in physiological channel benchmarking and multispectral face recognition. PMID:28809848

Switching in Feedforward Control of Grip Force During Tool-Mediated Interaction With Elastic Force Fields

PubMed Central

White, Olivier; Karniel, Amir; Papaxanthis, Charalambos; Barbiero, Marie; Nisky, Ilana

2018-01-01

Switched systems are common in artificial control systems. Here, we suggest that the brain adopts a switched feedforward control of grip forces during manipulation of objects. We measured how participants modulated grip force when interacting with soft and rigid virtual objects when stiffness varied continuously between trials. We identified a sudden phase transition between two forms of feedforward control that differed in the timing of the synchronization between the anticipated load force and the applied grip force. The switch occurred several trials after a threshold stiffness level in the range 100–200 N/m. These results suggest that in the control of grip force, the brain acts as a switching control system. This opens new research questions as to the nature of the discrete state variables that drive the switching. PMID:29930504

Continuous cognitive task promotes greater postural stability than an internal or external focus of attention.

PubMed

Polskaia, Nadia; Richer, Natalie; Dionne, Eliane; Lajoie, Yves

2015-02-01

Research has demonstrated clear advantages of using an external focus of attention in postural control tasks, presumably since it allows a more automatic control of posture to emerge. However, the influence of cognitive tasks on postural stability has produced discordant results. This study aimed to compare the effects of an internal focus of attention, an external focus of attention and a continuous cognitive task on postural control. Twenty healthy participants (21.4±2.6 years) were recruited for this study. They were asked to stand quietly on a force platform with their feet together in three different attentional focus conditions: an internal focus condition (minimizing movements of the hips), an external focus condition (minimizing movements of markers placed on the hips) and a cognitive task condition (silently counting the total number of times a single digit was verbalized in a 3-digit sequence comprised of 30 numbers). Results demonstrated improved stability while performing the cognitive task as opposed to the internal and external focus conditions, as evidenced by a reduction in sway area, sway variability in the anterior-posterior (AP) and medial-lateral (ML) directions, and mean velocity (ML only). Results suggest that the use of a continuous cognitive task permits attention to be withdrawn from the postural task, thereby facilitating a more automatic control of posture. Copyright © 2014 Elsevier B.V. All rights reserved.

Ordinary Least Squares Estimation of Parameters in Exploratory Factor Analysis with Ordinal Data

ERIC Educational Resources Information Center

Lee, Chun-Ting; Zhang, Guangjian; Edwards, Michael C.

2012-01-01

Exploratory factor analysis (EFA) is often conducted with ordinal data (e.g., items with 5-point responses) in the social and behavioral sciences. These ordinal variables are often treated as if they were continuous in practice. An alternative strategy is to assume that a normally distributed continuous variable underlies each ordinal variable.…

Data-based mechanistic modeling of dissolved organic carbon load through storms using continuous 15-minute resolution observations within UK upland watersheds

NASA Astrophysics Data System (ADS)

Jones, T.; Chappell, N. A.

2013-12-01

Few watershed modeling studies have addressed DOC dynamics through storm hydrographs (notable exceptions include Boyer et al., 1997 Hydrol Process; Jutras et al., 2011 Ecol Model; Xu et al., 2012 Water Resour Res). In part this has been a consequence of an incomplete understanding of the biogeochemical processes leading to DOC export to streams (Neff & Asner, 2001, Ecosystems) & an insufficient frequency of DOC monitoring to capture sometimes complex time-varying relationships between DOC & storm hydrographs (Kirchner et al., 2004, Hydrol Process). We present the results of a new & ongoing UK study that integrates two components - 1/ New observations of DOC concentrations (& derived load) continuously monitored at 15 minute intervals through multiple seasons for replicated watersheds; & 2/ A dynamic modeling technique that is able to quantify storage-decay effects, plus hysteretic, nonlinear, lagged & non-stationary relationships between DOC & controlling variables (including rainfall, streamflow, temperature & specific biogeochemical variables e.g., pH, nitrate). DOC concentration is being monitored continuously using the latest generation of UV spectrophotometers (i.e. S::CAN spectro::lysers) with in situ calibrations to laboratory analyzed DOC. The controlling variables are recorded simultaneously at the same stream stations. The watersheds selected for study are among the most intensively studied basins in the UK uplands, namely the Plynlimon & Llyn Brianne experimental basins. All contain areas of organic soils, with three having improved grasslands & three conifer afforested. The dynamic response characteristics (DRCs) that describe detailed DOC behaviour through sequences of storms are simulated using the latest identification routines for continuous time transfer function (CT-TF) models within the Matlab-based CAPTAIN toolbox (some incorporating nonlinear components). To our knowledge this is the first application of CT-TFs to modelling DOC processes. Furthermore this allows a data-based mechanistic (DBM) modelling philosophy to be followed where no assumptions about processes are defined a priori (given that dominant processes are often not known before analysis) & where the information contained in the time-series is used to identify multiple structures of models that are statistically robust. Within the final stage of DBM, biogeochemical & hydrological processes are interpreted from those models that are observable from the available stream time-series. We show that this approach can simulate the key features of DOC dynamics within & between storms & that some of the resultant response characteristics change with varying DOC processes in different seasons. Through the use of MISO (multiple-input single-output) models we demonstrate the relative importance of different variables (e.g., rainfall, temperature) in controlling DOC responses. The contrasting behaviour of the six experimental catchments is also reflected in differing response characteristics. These characteristics are shown to contribute to understanding of basin-integrated DOC export processes & to the ecosystem service impacts of DOC & color on commercial water treatment within the surrounding water supply basins.

Direct SQP-methods for solving optimal control problems with delays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goellmann, L.; Bueskens, C.; Maurer, H.

The maximum principle for optimal control problems with delays leads to a boundary value problem (BVP) which is retarded in the state and advanced in the costate function. Based on shooting techniques, solution methods for this type of BVP have been proposed. In recent years, direct optimization methods have been favored for solving control problems without delays. Direct methods approximate the control and the state over a fixed mesh and solve the resulting NLP-problem with SQP-methods. These methods dispense with the costate function and have shown to be robust and efficient. In this paper, we propose a direct SQP-method formore » retarded control problems. In contrast to conventional direct methods, only the control variable is approximated by e.g. spline-functions. The state is computed via a high order Runge-Kutta type algorithm and does not enter explicitly the NLP-problem through an equation. This approach reduces the number of optimization variables considerably and is implementable even on a PC. Our method is illustrated by the numerical solution of retarded control problems with constraints. In particular, we consider the control of a continuous stirred tank reactor which has been solved by dynamic programming. This example illustrates the robustness and efficiency of the proposed method. Open questions concerning sufficient conditions and convergence of discretized NLP-problems are discussed.« less

Secure quantum key distribution using continuous variables of single photons.

PubMed

Zhang, Lijian; Silberhorn, Christine; Walmsley, Ian A

2008-03-21

We analyze the distribution of secure keys using quantum cryptography based on the continuous variable degree of freedom of entangled photon pairs. We derive the information capacity of a scheme based on the spatial entanglement of photons from a realistic source, and show that the standard measures of security known for quadrature-based continuous variable quantum cryptography (CV-QKD) are inadequate. A specific simple eavesdropping attack is analyzed to illuminate how secret information may be distilled well beyond the bounds of the usual CV-QKD measures.

Serum magnesium but not calcium was associated with hemorrhagic transformation in stroke overall and stroke subtypes: a case-control study in China.

PubMed

Tan, Ge; Yuan, Ruozhen; Wei, ChenChen; Xu, Mangmang; Liu, Ming

2018-05-26

Association between serum calcium and magnesium versus hemorrhagic transformation (HT) remains to be identified. A total of 1212 non-thrombolysis patients with serum calcium and magnesium collected within 24 h from stroke onset were enrolled. Backward stepwise multivariate logistic regression analysis was conducted to investigate association between calcium and magnesium versus HT. Calcium and magnesium were entered into logistic regression analysis in two models, separately: model 1, as continuous variable (per 1-mmol/L increase), and model 2, as four-categorized variable (being collapsed into quartiles). HT occurred in 140 patients (11.6%). Serum calcium was slightly lower in patients with HT than in patient without HT (P = 0.273). But serum magnesium was significantly lower in patients with HT than in patients without HT (P = 0.007). In logistic regression analysis, calcium displayed no association with HT. Magnesium, as either continuous or four-categorized variable, was independently and inversely associated with HT in stroke overall and stroke of large-artery atherosclerosis (LAA). The results demonstrated that serum calcium had no association with HT in patients without thrombolysis after acute ischemic stroke. Serum magnesium in low level was independently associated with increasing HT in stroke overall and particularly in stroke of LAA.

A scheme for recording a fast process at nanosecond scale by using digital holographic interferometry with continuous wave laser

NASA Astrophysics Data System (ADS)

Wang, Jun; Zhao, Jianlin; Di, Jianglei; Jiang, Biqiang

2015-04-01

A scheme for recording fast process at nanosecond scale by using digital holographic interferometry with continuous wave (CW) laser is described and demonstrated experimentally, which employs delayed-time fibers and angular multiplexing technique and can realize the variable temporal resolution at nanosecond scale and different measured depths of object field at certain temporal resolution. The actual delay-time is controlled by two delayed-time fibers with different lengths. The object field information in two different states can be simultaneously recorded in a composite hologram. This scheme is also suitable for recording fast process at picosecond scale, by using an electro-optic modulator.

Mechanical desorption of a single chain: unusual aspects of phase coexistence at a first-order transition.

PubMed

Skvortsov, Alexander M; Klushin, Leonid I; Polotsky, Alexey A; Binder, Kurt

2012-03-01

The phase transition occurring when a single polymer chain adsorbed at a planar solid surface is mechanically desorbed is analyzed in two statistical ensembles. In the force ensemble, a constant force applied to the nongrafted end of the chain (that is grafted at its other end) is used as a given external control variable. In the z-ensemble, the displacement z of this nongrafted end from the surface is taken as the externally controlled variable. Basic thermodynamic parameters, such as the adsorption energy, exhibit a very different behavior as a function of these control parameters. In the thermodynamic limit of infinite chain length the desorption transition with the force as a control parameter clearly is discontinuous, while in the z-ensemble continuous variations are found. However, one should not be misled by a too-naive application of the Ehrenfest criterion to consider the transition as a continuous transition: rather, one traverses a two-phase coexistence region, where part of the chain is still adsorbed and the other part desorbed and stretched. Similarities with and differences from two-phase coexistence at vapor-liquid transitions are pointed out. The rounding of the singularities due to finite chain length is illustrated by exact calculations for the nonreversal random walk model on the simple cubic lattice. A new concept of local order parameter profiles for the description of the mechanical desorption of adsorbed polymers is suggested. This concept give evidence for both the existence of two-phase coexistence within single polymer chains for this transition and the anomalous character of this two-phase coexistence. Consequences for the proper interpretation of experiments performed in different ensembles are briefly mentioned.

Limb versus speech motor control: a conceptual review.

PubMed

Grimme, Britta; Fuchs, Susanne; Perrier, Pascal; Schöner, Gregor

2011-01-01

This paper presents a comparative conceptual review of speech and limb motor control. Speech is essentially cognitive in nature and constrained by the rules of language, while limb movement is often oriented to physical objects. We discuss the issue of intrinsic vs. extrinsic variables underlying the representations of motor goals as well as whether motor goals specify terminal postures or entire trajectories. Timing and coordination is recognized as an area of strong interchange between the two domains. Although coordination among different motor acts within a sequence and coarticulation are central to speech motor control, they have received only limited attention in manipulatory movements. The biomechanics of speech production is characterized by the presence of soft tissue, a variable number of degrees of freedom, and the challenges of high rates of production, while limb movements deal more typically with inertial constraints from manipulated objects. This comparative review thus leads us to identify many strands of thinking that are shared across the two domains, but also points us to issues on which approaches in the two domains differ. We conclude that conceptual interchange between the fields of limb and speech motor control has been useful in the past and promises continued benefit.

Criteria for genuine N -partite continuous-variable entanglement and Einstein-Podolsky-Rosen steering

NASA Astrophysics Data System (ADS)

Teh, R. Y.; Reid, M. D.

2014-12-01

Following previous work, we distinguish between genuine N -partite entanglement and full N -partite inseparability. Accordingly, we derive criteria to detect genuine multipartite entanglement using continuous-variable (position and momentum) measurements. Our criteria are similar but different to those based on the van Loock-Furusawa inequalities, which detect full N -partite inseparability. We explain how the criteria can be used to detect the genuine N -partite entanglement of continuous variable states generated from squeezed and vacuum state inputs, including the continuous-variable Greenberger-Horne-Zeilinger state, with explicit predictions for up to N =9 . This makes our work accessible to experiment. For N =3 , we also present criteria for tripartite Einstein-Podolsky-Rosen (EPR) steering. These criteria provide a means to demonstrate a genuine three-party EPR paradox, in which any single party is steerable by the remaining two parties.

A Hierarchical Modulation Coherent Communication Scheme for Simultaneous Four-State Continuous-Variable Quantum Key Distribution and Classical Communication

NASA Astrophysics Data System (ADS)

Yang, Can; Ma, Cheng; Hu, Linxi; He, Guangqiang

2018-06-01

We present a hierarchical modulation coherent communication protocol, which simultaneously achieves classical optical communication and continuous-variable quantum key distribution. Our hierarchical modulation scheme consists of a quadrature phase-shifting keying modulation for classical communication and a four-state discrete modulation for continuous-variable quantum key distribution. The simulation results based on practical parameters show that it is feasible to transmit both quantum information and classical information on a single carrier. We obtained a secure key rate of 10^{-3} bits/pulse to 10^{-1} bits/pulse within 40 kilometers, and in the meantime the maximum bit error rate for classical information is about 10^{-7}. Because continuous-variable quantum key distribution protocol is compatible with standard telecommunication technology, we think our hierarchical modulation scheme can be used to upgrade the digital communication systems to extend system function in the future.

Universal Quantum Computing with Arbitrary Continuous-Variable Encoding.

PubMed

Lau, Hoi-Kwan; Plenio, Martin B

2016-09-02

Implementing a qubit quantum computer in continuous-variable systems conventionally requires the engineering of specific interactions according to the encoding basis states. In this work, we present a unified formalism to conduct universal quantum computation with a fixed set of operations but arbitrary encoding. By storing a qubit in the parity of two or four qumodes, all computing processes can be implemented by basis state preparations, continuous-variable exponential-swap operations, and swap tests. Our formalism inherits the advantages that the quantum information is decoupled from collective noise, and logical qubits with different encodings can be brought to interact without decoding. We also propose a possible implementation of the required operations by using interactions that are available in a variety of continuous-variable systems. Our work separates the "hardware" problem of engineering quantum-computing-universal interactions, from the "software" problem of designing encodings for specific purposes. The development of quantum computer architecture could hence be simplified.

Universal Quantum Computing with Arbitrary Continuous-Variable Encoding

NASA Astrophysics Data System (ADS)

Lau, Hoi-Kwan; Plenio, Martin B.

2016-09-01

Implementing a qubit quantum computer in continuous-variable systems conventionally requires the engineering of specific interactions according to the encoding basis states. In this work, we present a unified formalism to conduct universal quantum computation with a fixed set of operations but arbitrary encoding. By storing a qubit in the parity of two or four qumodes, all computing processes can be implemented by basis state preparations, continuous-variable exponential-swap operations, and swap tests. Our formalism inherits the advantages that the quantum information is decoupled from collective noise, and logical qubits with different encodings can be brought to interact without decoding. We also propose a possible implementation of the required operations by using interactions that are available in a variety of continuous-variable systems. Our work separates the "hardware" problem of engineering quantum-computing-universal interactions, from the "software" problem of designing encodings for specific purposes. The development of quantum computer architecture could hence be simplified.

Continuous-variable protocol for oblivious transfer in the noisy-storage model.

PubMed

Furrer, Fabian; Gehring, Tobias; Schaffner, Christian; Pacher, Christoph; Schnabel, Roman; Wehner, Stephanie

2018-04-13

Cryptographic protocols are the backbone of our information society. This includes two-party protocols which offer protection against distrustful players. Such protocols can be built from a basic primitive called oblivious transfer. We present and experimentally demonstrate here a quantum protocol for oblivious transfer for optical continuous-variable systems, and prove its security in the noisy-storage model. This model allows us to establish security by sending more quantum signals than an attacker can reliably store during the protocol. The security proof is based on uncertainty relations which we derive for continuous-variable systems, that differ from the ones used in quantum key distribution. We experimentally demonstrate in a proof-of-principle experiment the proposed oblivious transfer protocol for various channel losses by using entangled two-mode squeezed states measured with balanced homodyne detection. Our work enables the implementation of arbitrary two-party quantum cryptographic protocols with continuous-variable communication systems.

Continuous variable quantum key distribution with modulated entangled states.

PubMed

Madsen, Lars S; Usenko, Vladyslav C; Lassen, Mikael; Filip, Radim; Andersen, Ulrik L

2012-01-01

Quantum key distribution enables two remote parties to grow a shared key, which they can use for unconditionally secure communication over a certain distance. The maximal distance depends on the loss and the excess noise of the connecting quantum channel. Several quantum key distribution schemes based on coherent states and continuous variable measurements are resilient to high loss in the channel, but are strongly affected by small amounts of channel excess noise. Here we propose and experimentally address a continuous variable quantum key distribution protocol that uses modulated fragile entangled states of light to greatly enhance the robustness to channel noise. We experimentally demonstrate that the resulting quantum key distribution protocol can tolerate more noise than the benchmark set by the ideal continuous variable coherent state protocol. Our scheme represents a very promising avenue for extending the distance for which secure communication is possible.

Continuous-variable quantum Gaussian process regression and quantum singular value decomposition of nonsparse low-rank matrices

NASA Astrophysics Data System (ADS)

Das, Siddhartha; Siopsis, George; Weedbrook, Christian

2018-02-01

With the significant advancement in quantum computation during the past couple of decades, the exploration of machine-learning subroutines using quantum strategies has become increasingly popular. Gaussian process regression is a widely used technique in supervised classical machine learning. Here we introduce an algorithm for Gaussian process regression using continuous-variable quantum systems that can be realized with technology based on photonic quantum computers under certain assumptions regarding distribution of data and availability of efficient quantum access. Our algorithm shows that by using a continuous-variable quantum computer a dramatic speedup in computing Gaussian process regression can be achieved, i.e., the possibility of exponentially reducing the time to compute. Furthermore, our results also include a continuous-variable quantum-assisted singular value decomposition method of nonsparse low rank matrices and forms an important subroutine in our Gaussian process regression algorithm.

Do kinematic metrics of walking balance adapt to perturbed optical flow?

PubMed

Thompson, Jessica D; Franz, Jason R

2017-08-01

Visual (i.e., optical flow) perturbations can be used to study balance control and balance deficits. However, it remains unclear whether walking balance control adapts to such perturbations over time. Our purpose was to investigate the propensity for visuomotor adaptation in walking balance control using prolonged exposure to optical flow perturbations. Ten subjects (age: 25.4±3.8years) walked on a treadmill while watching a speed-matched virtual hallway with and without continuous mediolateral optical flow perturbations of three different amplitudes. Each of three perturbation trials consisted of 8min of prolonged exposure followed by 1min of unperturbed walking. Using 3D motion capture, we analyzed changes in foot placement kinematics and mediolateral sacrum motion. At their onset, perturbations elicited wider and shorter steps, alluding to a more cautious, general anticipatory balance control strategy. As perturbations continued, foot placement tended toward values seen during unperturbed walking while step width variability and mediolateral sacrum motion concurrently increased. Our findings suggest that subjects progressively shifted from a general anticipatory balance control strategy to a reactive, task-specific strategy using step-to-step adjustments. Prolonged exposure to optical flow perturbations may have clinical utility to reinforce reactive, task-specific balance control through training. Copyright © 2017 Elsevier B.V. All rights reserved.

Approximation-based adaptive tracking control of pure-feedback nonlinear systems with multiple unknown time-varying delays.

PubMed

Wang, Min; Ge, Shuzhi Sam; Hong, Keum-Shik

2010-11-01

This paper presents adaptive neural tracking control for a class of non-affine pure-feedback systems with multiple unknown state time-varying delays. To overcome the design difficulty from non-affine structure of pure-feedback system, mean value theorem is exploited to deduce affine appearance of state variables x(i) as virtual controls α(i), and of the actual control u. The separation technique is introduced to decompose unknown functions of all time-varying delayed states into a series of continuous functions of each delayed state. The novel Lyapunov-Krasovskii functionals are employed to compensate for the unknown functions of current delayed state, which is effectively free from any restriction on unknown time-delay functions and overcomes the circular construction of controller caused by the neural approximation of a function of u and [Formula: see text] . Novel continuous functions are introduced to overcome the design difficulty deduced from the use of one adaptive parameter. To achieve uniformly ultimate boundedness of all the signals in the closed-loop system and tracking performance, control gains are effectively modified as a dynamic form with a class of even function, which makes stability analysis be carried out at the present of multiple time-varying delays. Simulation studies are provided to demonstrate the effectiveness of the proposed scheme.

Anterior Cingulate Cortex γ-Aminobutyric Acid in Depressed Adolescents

PubMed Central

Gabbay, Vilma; Mao, Xiangling; Klein, Rachel G.; Ely, Benjamin A.; Babb, James S.; Panzer, Aviva M.; Alonso, Carmen M.; Shungu, Dikoma C.

2013-01-01

Context Anhedonia, a core symptom of major depressive disorder (MDD) and highly variable among adolescents with MDD, may involve alterations in the major inhibitory amino acid neurotransmitter system of γ-aminobutyric acid (GABA). Objective To test whether anterior cingulate cortex (ACC) GABA levels, measured by proton magnetic resonance spectroscopy, are decreased in adolescents with MDD. The associations of GABA alterations with the presence and severity of anhedonia were explored. Design Case-control, cross-sectional study using single-voxel proton magnetic resonance spectroscopy at 3 T. Setting Two clinical research divisions at 2 teaching hospitals. Participants Twenty psychotropic medication-free adolescents with MDD (10 anhedonic, 12 female, aged 12–19 years) with episode duration of 8 weeks or more and 21 control subjects group matched for sex and age. Main Outcome Measures Anterior cingulate cortex GABA levels expressed as ratios relative to unsuppressed voxel tissue water (w) and anhedonia scores expressed as a continuous variable. Results Compared with control subjects, adolescents with MDD had significantly decreased ACC GABA/w (t= 3.2; P<.003). When subjects with MDD were categorized based on the presence of anhedonia, only anhedonic patients had decreased GABA/w levels compared with control subjects (t=4.08; P<.001; PTukey<.001). Anterior cingulate cortex GABA/w levels were negatively correlated with anhedonia scores for the whole MDD group (r = −0.50; P = .02), as well as for the entire participant sample including the control subjects (r=−0.54; P<.001). Anterior cingulate cortex white matter was also significantly decreased in adolescents with MDD compared with controls (P=.04). Conclusions These findings suggest that GABA, the major inhibitory neurotransmitter in the brain, may be implicated in adolescent MDD and, more specifically, in those with anhedonia. In addition, use of a continuous rather than categorical scale of anhedonia, as in the present study, may permit greater specificity in evaluating this important clinical feature. PMID:21969419

The Challenge of Reproducibility and Accuracy in Nutrition Research: Resources and Pitfalls1234

PubMed Central

Kuszak, Adam J; Williamson, John S; Hopp, D Craig; Betz, Joseph M

2016-01-01

Inconsistent and contradictory results from nutrition studies conducted by different investigators continue to emerge, in part because of the inherent variability of natural products, as well as the unknown and therefore uncontrolled variables in study populations and experimental designs. Given these challenges inherent in nutrition research, it is critical for the progress of the field that researchers strive to minimize variability within studies and enhance comparability between studies by optimizing the characterization, control, and reporting of products, reagents, and model systems used, as well as the rigor and reporting of experimental designs, protocols, and data analysis. Here we describe some recent developments relevant to research on plant-derived products used in nutrition research, highlight some resources for optimizing the characterization and reporting of research using these products, and describe some of the pitfalls that may be avoided by adherence to these recommendations. PMID:26980822

Axial force and efficiency tests of fixed center variable speed belt drive

NASA Technical Reports Server (NTRS)

Bents, D. J.

1981-01-01

An investigation of how the axial force varies with the centerline force at different speed ratios, speeds, and loads, and how the drive's transmission efficiency is affected by these related forces is described. The tests, intended to provide a preliminary performance and controls characterization for a variable speed belt drive continuously variable transmission (CVT), consisted of the design and construction of an experimental test rig geometrically similar to the CVT, and operation of that rig at selected speed ratios and power levels. Data are presented which show: how axial forces exerted on the driver and driven sheaves vary with the centerline force at constant values of speed ratio, speed, and output power; how the transmission efficiency varies with centerline force and how it is also a function of the V belt coefficient; and the axial forces on both sheaves as normalized functions of the traction coefficient.

Lognormal kriging for the assessment of reliability in groundwater quality control observation networks

USGS Publications Warehouse

Candela, L.; Olea, R.A.; Custodio, E.

1988-01-01

Groundwater quality observation networks are examples of discontinuous sampling on variables presenting spatial continuity and highly skewed frequency distributions. Anywhere in the aquifer, lognormal kriging provides estimates of the variable being sampled and a standard error of the estimate. The average and the maximum standard error within the network can be used to dynamically improve the network sampling efficiency or find a design able to assure a given reliability level. The approach does not require the formulation of any physical model for the aquifer or any actual sampling of hypothetical configurations. A case study is presented using the network monitoring salty water intrusion into the Llobregat delta confined aquifer, Barcelona, Spain. The variable chloride concentration used to trace the intrusion exhibits sudden changes within short distances which make the standard error fairly invariable to changes in sampling pattern and to substantial fluctuations in the number of wells. ?? 1988.

Investigation of Coastal Hydrogeology Utilizing Geophysical and Geochemical Tools along the Broward County Coast, Florida

USGS Publications Warehouse

Reich, Christopher D.; Swarzenski, Peter W.; Greenwood, W. Jason; Wiese, Dana S.

2008-01-01

Geophysical (CHIRP, boomer, and continuous direct-current resistivity) and geochemical tracer studies (continuous and time-series 222Radon) were conducted along the Broward County coast from Port Everglades to Hillsboro Inlet, Florida. Simultaneous seismic, direct-current resistivity, and radon surveys in the coastal waters provided information to characterize the geologic framework and identify potential groundwater-discharge sites. Time-series radon at the Nova Southeastern University National Coral Reef Institute (NSU/NCRI) seawall indicated a very strong tidally modulated discharge of ground water with 222Rn activities ranging from 4 to 10 disintegrations per minute per liter depending on tidal stage. CHIRP seismic data provided very detailed bottom profiles (i.e., bathymetry); however, acoustic penetration was poor and resulted in no observed subsurface geologic structure. Boomer data, on the other hand, showed features that are indicative of karst, antecedent topography (buried reefs), and sand-filled troughs. Continuous resistivity profiling (CRP) data showed slight variability in the subsurface along the coast. Subtle changes in subsurface resistivity between nearshore (higher values) and offshore (lower values) profiles may indicate either a freshening of subsurface water nearshore or a change in sediment porosity or lithology. Further lithologic and hydrologic controls from sediment or rock cores or well data are needed to constrain the variability in CRP data.

The Use of Research-Based Instructional Strategies in Introductory Physics: Where do Faculty Leave the Innovation-Decision Process?

NASA Astrophysics Data System (ADS)

Henderson, Charles; Dancy, Melissa; Niewiadomska-Bugaj, Magdalena

2013-03-01

During the Fall of 2008 a web survey was completed by a representative sample of 722 United States physics faculty. In this talk we will briefly present summary statistics to describe faculty knowledge about and use of 24 specific research-based instructional strategies (RBIS). We will then analyze the results based on a four stage model of the innovation-decision process: knowledge, trial, continuation, and high use. The largest losses occur at the continuation stage, with approximately 1/3 of faculty discontinuing use of all RBIS after trying one or more of these strategies. These results suggest that common dissemination strategies are good at creating knowledge about RBIS and motivation to try a RBIS, but more work is needed to support faculty during implementation and continued use of RBIS. Based on a logistic regression analysis, only nine of the 20 potential predictor variables measured were statistically significant when controlling for other variables. Faculty age, institutional type, and percentage of job related to teaching were not found to be correlated with knowledge or use at any stage. High research productivity and large class sizes were not found to be barriers to use of at least some RBIS. Supported by NSF #0715698.

Explosive Strength Imbalances in Professional Basketball Players

PubMed Central

Schiltz, Marc; Lehance, Cédric; Maquet, Didier; Bury, Thierry; Crielaard, Jean-Michel; Croisier, Jean-Louis

2009-01-01

Context: Despite the high rate of lower limb injuries in basketball players, studies of the dominant-limb effect in elite athletes often neglect injury history. Objective: To determine lower limb explosive-strength asymmetries in professional basketball players compared with junior basketball players and control participants. Design: Cohort study. Setting: Academic medical institution. Patients or Other Participants: 15 professional basketball players, 10 junior basketball players, and 20 healthy men. Main Outcome Measure(s): We performed an isokinetic examination to evaluate the knee extensor (Ext) and flexor (Fl) concentric peak torque at 60°·s−1 and 240°·s−1 and (Fl only) eccentric peak torque at 30°·s−1 and 120°·s−1. Functional evaluation included countermovement jump, countermovement jump with arms, 10-m sprint, single-leg drop jump, and single-leg, 10-second continuous jumping. Variables were compared among groups using analysis of variance or a generalized linear mixed model for bilateral variables. Results: The 2 groups of basketball players demonstrated better isokinetic and functional performances than the control group did. No differences in functional or relative isokinetic variables were noted between professional and junior basketball players. Professional players with a history of knee injury failed to reach normal knee extensor strength at 60°·s−1. Knee Ext (60°·s−1) and Fl (eccentric 120°·s−1) torque values as well as 10-second continuous jumping scores were higher in those professional players without a history of knee injury than those with such a history. Compared with the group without a history of knee injury, the group with a history of knee injury maintained leg asymmetry ratios greater than 10% for almost all isokinetic variables and more than 15% for unilateral functional variables. Conclusions: The relative isokinetic and functional performances of professional basketball players were similar to those of junior players, with no dominant-side effect. A history of knee injury in the professional athlete, however, was reflected in bilateral isokinetic and functional asymmetries and should be considered in future studies of explosive strength. PMID:19180217

The effect of continuing professional development on public complaints: a case-control study.

PubMed

Wenghofer, Elizabeth F; Campbell, Craig; Marlow, Bernard; Kam, Sophia M; Carter, Lorraine; McCauley, William

2015-03-01

This study aimed to investigate the relationship between participation in different types of continuing professional development (CPD), and incidences and types of public complaint against physicians. Cases included physicians against whom complaints were made by members of the public to the medical regulatory body in Ontario, Canada, the College of Physicians and Surgeons of Ontario (CPSO), during 2008 and 2009. The control cohort included physicians against whom no complaints were documented during the same period. We focused on complaints related to physician communication, quality of care and professionalism. The CPD data included all Royal College of Physicians and Surgeons of Canada (RCPSC) and College of Family Physicians of Canada (CFPC) CPD programme activities reported by the case and control physicians. Multivariate logistic regression models were used to determine if the independent variable, reported participation in CPD, was associated with the dependent variable, the complaints-related status of the physician in the year following reported CPD activities. A total of 2792 physicians were included in the study. There was a significant relationship between participation in CPD, type of CPD and type of complaint received. Analysis indicated that physicians who reported overall participation in CPD activities were significantly less likely (odds ratio 0.604; p = 0.028) to receive quality of care-related complaints than those who did not report participating in CPD. Additionally, participation in group-based CPD was less likely (OR 0.681; p = 0.041) to result in quality of care-related complaints. The findings demonstrate a positive relationship between participation in the national CPD programmes of the CFPC and RCPSC, and lower numbers of public complaints received by the CPSO. As certification bodies and regulators alike are increasingly mandating CPD, they are encouraged to continually evaluate the effectiveness of their programmes to maximise programme impact on physician performance at the population level. © 2015 John Wiley & Sons Ltd.

The neurovascular complexity index as a potential indicator of traumatic brain injury severity: A case-series study.

PubMed

Howard, Jeffrey T; Janak, Jud C; Bukhman, Vladislav; Robertson, Claudia; Frolov, Iurii; Nawn, Corinne D; Schiller, Alicia M; Convertino, Victor A

2017-07-01

Multimodal monitoring of brain physiology following a traumatic brain injury (TBI) shows promise as a strategy to improve management and outcomes of TBI patients within civilian and military trauma. Valid and reliable measures of different aspects of brain physiology following a TBI could prove critical to accurately capturing these changes. Using a case-series design with a control subject group comparison, we evaluated a new proprietary algorithm called the Neurovascular Complexity Index (NCI) using transcranial Doppler to noninvasively obtain measures of cerebral blood flow variability. Baseline NCI data from 169 control subjects were compared with 12 patients with moderate to severe TBI. Patients with TBI exhibited significantly greater mean and variability in NCI scores compared with control subjects (F = 195.48; p < 0.001). The mean absolute deviation (MAD) of NCI scores increased significantly and in a monotonic fashion with severity of injury, where control subjects exhibited a small MAD of 0.44, patients with moderate TBI had a higher MAD of 4.20, and patients with severe TBI had an MAD of 6.51 (p < 0.001). Advancement in multimodal monitoring of TBI patients is important in reducing the potential risk of secondary injury. This study reports results indicating that a new noninvasive quantifiable assessment of TBI based on a noninvasive measure of cerebral blood flow variability shows potential for continuous monitoring and early identification of brain-injured patients, deployable in far-forward military environments, to better inform individualized management. Case series, level IV.

The gender earnings gap among pharmacists.

PubMed

Carvajal, Manuel J; Armayor, Graciela M; Deziel, Lisa

2012-01-01

A gender earnings gap exists across professions. Compared with men, women earn consistently lower income levels. The determinants of wages and salaries should be explored to assess whether a gender earnings gap exists in the pharmacy profession. The objectives of this study were to (1) compare the responses of male and female pharmacists' earnings with human-capital stock, workers' preferences, and opinion variables and (2) assess whether the earnings determination models for male and female pharmacists yielded similar results in estimating the wage-and-salary gap through earnings projections, the influence of each explanatory variable, and gender differences in statistical significance. Data were collected through the use of a 37-question survey mailed to registered pharmacists in South Florida, United States. Earnings functions were formulated and tested separately for male and female pharmacists using unlogged and semilog equation forms. Number of hours worked, human-capital stock, job preferences, and opinion variables were hypothesized to explain wage-and-salary differentials. The empirical evidence led to 3 major conclusions: (1) men's and women's earnings sometimes were influenced by different stimuli, and when they responded to the same variables, the effect often was different; (2) although the influence of some explanatory variables on earnings differed in the unlogged and semilog equations, the earnings projections derived from both equation forms for male and female pharmacists were remarkably similar and yielded nearly identical male-female earnings ratios; and (3) controlling for number of hours worked, human-capital stock, job preferences, and opinion variables reduced the initial unadjusted male-female earnings ratios only slightly, which pointed toward the presence of gender bias. After controlling for human-capital stock, job-related characteristics, and opinion variables, male pharmacists continued to earn higher income levels than female pharmacists. Copyright © 2012 Elsevier Inc. All rights reserved.

The impact of a disease management programme for type 2 diabetes on health-related quality of life: multilevel analysis of a cluster-randomised controlled trial.

PubMed

Panisch, Sigrid; Johansson, Tim; Flamm, Maria; Winkler, Henrike; Weitgasser, Raimund; Sönnichsen, Andreas C

2018-01-01

Type 2 diabetes is a chronic disease associated with poorer health outcomes and decreased health related quality of life (HRQoL). The aim of this analysis was to explore the impact of a disease management programme (DMP) in type 2 diabetes on HRQoL. A multilevel model was used to explain the variation in EQ-VAS. A cluster-randomized controlled trial-analysis of the secondary endpoint HRQoL. Our study population were general practitioners and patients in the province of Salzburg. The DMP "Therapie-Aktiv" was implemented in the intervention group, and controls received usual care. Outcome measure was a change in EQ-VAS after 12 months. For comparison of rates, we used Fisher's Exact test; for continuous variables the independent T test or Welch test were used. In the multilevel modeling, we examined various models, continuously adding variables to explain the variation in the dependent variable, starting with an empty model, including only the random intercept. We analysed random effects parameters in order to disentangle variation of the final EQ-VAS. The EQ-VAS significantly increased within the intervention group (mean difference 2.19, p = 0.005). There was no significant difference in EQ-VAS between groups (mean difference 1.00, p = 0.339). In the intervention group the improvement was more distinct in women (2.46, p = 0.036) compared to men (1.92, p = 0.063). In multilevel modeling, sex, age, family and work circumstances, any macrovascular diabetic complication, duration of diabetes, baseline body mass index and baseline EQ-VAS significantly influence final EQ-VAS, while DMP does not. The final model explains 28.9% (EQ-VAS) of the total variance. Most of the unexplained variance was found on patient-level (95%) and less on GP-level (5%). DMP "Therapie-Aktiv" has no significant impact on final EQ-VAS. The impact of DMPs in type 2 diabetes on HRQoL is still unclear and future programmes should focus on patient specific needs and predictors in order to improve HRQoL. Trial registration Current Controlled trials Ltd., ISRCTN27414162.

State-Level Point-of-Sale Tobacco News Coverage and Policy Progression Over a 2-Year Period.

PubMed

Myers, Allison E; Southwell, Brian G; Ribisl, Kurt M; Moreland-Russell, Sarah; Bowling, J Michael; Lytle, Leslie A

2018-01-01

Mass media content may play an important role in policy change. However, the empirical relationship between media advocacy efforts and tobacco control policy success has rarely been studied. We examined the extent to which newspaper content characteristics (volume, slant, frame, source, use of evidence, and degree of localization) that have been identified as important in past descriptive studies were associated with policy progression over a 2-year period in the context of point-of-sale (POS) tobacco control. We used regression analyses to test the relationships between newspaper content and policy progression from 2012 to 2014. The dependent variable was the level of implementation of state-level POS tobacco control policies at Time 2. Independent variables were newspaper article characteristics (volume, slant, frame, source, use of evidence, and degree of localization) and were collected via content analysis of the articles. State-level policy environment contextual variables were examined as confounders. Positive, significant bivariate relationships exist between characteristics of news content (e.g., high overall volume, public health source present, local quote and local angle present, and pro-tobacco control slant present) and Time 2 POS score. However, in a multivariate model controlling for other factors, significant relationships did not hold. Newspaper coverage can be a marker of POS policy progression. Whether media can influence policy implementation remains an important question. Future work should continue to tease out and confirm the unique characteristics of media content that are most associated with subsequent policy progression, in order to inform media advocacy efforts.

Shiftwork in the Norwegian petroleum industry: overcoming difficulties with family and social life – a cross sectional study

PubMed Central

Ljoså, Cathrine Haugene; Lau, Bjørn

2009-01-01

Background Continuous shift schedules are required in the petroleum industry because of its dependency on uninterrupted production. Although shiftwork affects health, less is known about its effects on social and domestic life. Methods Consequently, we studied these relationships in a sample of 1697 (response rate 55.9%) petroleum workers who worked onshore and offshore for a Norwegian oil and gas company. We also examined the roles of coping strategies and locus of control for handling self-reported problems with social and domestic life. A questionnaire containing scales from the Standard Shiftwork Index and Shiftwork Locus of Control was answered electronically. Results In general, only a few participants reported that their shift schedule affected their social and domestic/family life, and several participants had enough time to spend by themselves and with their partner, close family, friends, and children. Despite this general positive trend, differences were found for shift type and individual factors such as locus of control and coping strategies. Internal locus of control was associated positively with all the dependent variables. However, engaging problem-focused coping strategies were associated only slightly with the dependent variables, while disengaging emotion-focused coping strategies were negatively associated with the dependent variables. Conclusion Since most participants reported few problems with social and domestic/family life, the availability of more leisure time may be a positive feature of shiftwork in the Norwegian petroleum industry. Locus of control and the use of coping strategies were important for shiftworkers' social and domestic/family life. PMID:19650903

Family and parenting characteristics associated with marijuana use by Chilean adolescents

PubMed Central

Bares, Cristina B; Delva, Jorge; Grogan-Kaylor, Andrew; Andrade, Fernando

2011-01-01

Objective Family involvement and several characteristics of parenting have been suggested to be protective factors for adolescent substance use. Some parenting behaviors may have stronger relationships with adolescent behavior while others may have associations with undesirable behavior among youth. Although it is generally acknowledged that families play an important role in the lives of Chilean adolescents, scant research exists on how different family and parenting factors may be associated with marijuana use and related problems in this population which has one of the highest rates of drug use in Latin America. Methods Using logistic regression and negative binomial regression, we examined whether a large number of family and parenting variables were associated with the possibility of Chilean adolescents ever using marijuana, and with marijuana-related problems. Analyses controlled for a number of demographic and peer-related variables. Results Controlling for other parenting and family variables, adolescent reports of parental marijuana use showed a significant and positive association with adolescent marijuana use. The multivariate models also revealed that harsh parenting by fathers was the only family variable associated with the number of marijuana-related problems youth experienced. Conclusion Of all the family and parenting variables studied, perceptions of parental use of marijuana and harsh parenting by fathers were predictors for marijuana use, and the experience of marijuana-related problems. Prevention interventions need to continue emphasizing the critical socializing role that parental behavior plays in their children’s development and potential use of marijuana. PMID:21660209

Wireless Monitoring of Induction Machine Rotor Physical Variables

PubMed Central

Doolan Fernandes, Jefferson; Carvalho Souza, Francisco Elvis; de Paiva, José Alvaro

2017-01-01

With the widespread use of electric machines, there is a growing need to extract information from the machines to improve their control systems and maintenance management. The present work shows the development of an embedded system to perform the monitoring of the rotor physical variables of a squirrel cage induction motor. The system is comprised of: a circuit to acquire desirable rotor variable(s) and value(s) that send it to the computer; a rectifier and power storage circuit that converts an alternating current in a continuous current but also stores energy for a certain amount of time to wait for the motor’s shutdown; and a magnetic generator that harvests energy from the rotating field to power the circuits mentioned above. The embedded system is set on the rotor of a 5 HP squirrel cage induction motor, making it difficult to power the system because it is rotating. This problem can be solved with the construction of a magnetic generator device to avoid the need of using batteries or collector rings and will send data to the computer using a wireless NRF24L01 module. For the proposed system, initial validation tests were made using a temperature sensor (DS18b20), as this variable is known as the most important when identifying the need for maintenance and control systems. Few tests have shown promising results that, with further improvements, can prove the feasibility of using sensors in the rotor. PMID:29156564

Wireless Monitoring of Induction Machine Rotor Physical Variables.

PubMed

Doolan Fernandes, Jefferson; Carvalho Souza, Francisco Elvis; Cipriano Maniçoba, Glauco George; Salazar, Andrés Ortiz; de Paiva, José Alvaro

2017-11-18

With the widespread use of electric machines, there is a growing need to extract information from the machines to improve their control systems and maintenance management. The present work shows the development of an embedded system to perform the monitoring of the rotor physical variables of a squirrel cage induction motor. The system is comprised of: a circuit to acquire desirable rotor variable(s) and value(s) that send it to the computer; a rectifier and power storage circuit that converts an alternating current in a continuous current but also stores energy for a certain amount of time to wait for the motor's shutdown; and a magnetic generator that harvests energy from the rotating field to power the circuits mentioned above. The embedded system is set on the rotor of a 5 HP squirrel cage induction motor, making it difficult to power the system because it is rotating. This problem can be solved with the construction of a magnetic generator device to avoid the need of using batteries or collector rings and will send data to the computer using a wireless NRF24L01 module. For the proposed system, initial validation tests were made using a temperature sensor (DS18b20), as this variable is known as the most important when identifying the need for maintenance and control systems. Few tests have shown promising results that, with further improvements, can prove the feasibility of using sensors in the rotor.

Robust decentralized hybrid adaptive output feedback fuzzy control for a class of large-scale MIMO nonlinear systems and its application to AHS.

PubMed

Huang, Yi-Shao; Liu, Wel-Ping; Wu, Min; Wang, Zheng-Wu

2014-09-01

This paper presents a novel observer-based decentralized hybrid adaptive fuzzy control scheme for a class of large-scale continuous-time multiple-input multiple-output (MIMO) uncertain nonlinear systems whose state variables are unmeasurable. The scheme integrates fuzzy logic systems, state observers, and strictly positive real conditions to deal with three issues in the control of a large-scale MIMO uncertain nonlinear system: algorithm design, controller singularity, and transient response. Then, the design of the hybrid adaptive fuzzy controller is extended to address a general large-scale uncertain nonlinear system. It is shown that the resultant closed-loop large-scale system keeps asymptotically stable and the tracking error converges to zero. The better characteristics of our scheme are demonstrated by simulations. Copyright © 2014. Published by Elsevier Ltd.

Design, experimentation, and modeling of a novel continuous biodrying process

NASA Astrophysics Data System (ADS)

Navaee-Ardeh, Shahram

Massive production of sludge in the pulp and paper industry has made the effective sludge management increasingly a critical issue for the industry due to high landfill and transportation costs, and complex regulatory frameworks for options such as sludge landspreading and composting. Sludge dewatering challenges are exacerbated at many mills due to improved in-plant fiber recovery coupled with increased production of secondary sludge, leading to a mixed sludge with a high proportion of biological matter which is difficult to dewater. In this thesis, a novel continuous biodrying reactor was designed and developed for drying pulp and paper mixed sludge to economic dry solids level so that the dried sludge can be economically and safely combusted in a biomass boiler for energy recovery. In all experimental runs the economic dry solids level was achieved, proving the process successful. In the biodrying process, in addition to the forced aeration, the drying rates are enhanced by biological heat generated through the microbial activity of mesophilic and thermophilic microorganisms naturally present in the porous matrix of mixed sludge. This makes the biodrying process more attractive compared to the conventional drying techniques because the reactor is a self-heating process. The reactor is divided into four nominal compartments and the mixed sludge dries as it moves downward in the reactor. The residence times were 4-8 days, which are 2-3 times shorter than the residence times achieved in a batch biodrying reactor previously studied by our research group for mixed sludge drying. A process variable analysis was performed to determine the key variable(s) in the continuous biodrying reactor. Several variables were investigated, namely: type of biomass feed, pH of biomass, nutrition level (C/N ratio), residence times, recycle ratio of biodried sludge, and outlet relative humidity profile along the reactor height. The key variables that were identified in the continuous biodrying reactor were the type of biomass feed and the outlet relative humidity profiles. The biomass feed is mill specific and since one mill was studied for this study, the nutrition level of the biomass feed was found adequate for the microbial activity, and hence the type of biomass is a fixed parameter. The influence of outlet relative humidity profile was investigated on the overall performance and the complexity index of the continuous biodrying reactor. The best biodrying efficiency was achieved at an outlet relative humidity profile which controls the removal of unbound water at the wet-bulb temperature in the 1st and 2nd compartments of the reactor, and the removal of bound water at the dry-bulb temperature in the 3rd and 4th compartments. Through a systematic modeling approach, a 2-D model was developed to describe the transport phenomena in the continuous biodrying reactor. The results of the 2-D model were in satisfactory agreement with the experimental data. It was found that about 30% w/w of the total water removal (drying rate) takes place in the 1st and 2nd compartments mainly under a convection dominated mechanism, whereas about 70% w/w of the total water removal takes place in the 3rd and 4th compartments where a bioheat-diffusion dominated mechanism controls the transport phenomena. The 2-D model was found to be an appropriate tool for the estimation of the total water removal rate (drying rate) in the continuous biodrying reactor when compared to the 1-D model. A dimensionless analysis was performed on the 2-D model and established the preliminary criteria for the scale-up of the continuous biodrying process. Finally, a techno-economic assessment of the continuous biodrying process revealed that there is great potential for the implementation of the biodrying process in Canadian pulp and paper mills. The techno-economic results were compared to the other competitive existing drying technologies. It was proven that the continuous biodrying process results in significant economic benefits and has great potential to address the current industrial problems associated with sludge management.

Influences of personality traits and continuation intentions on physical activity participation within the theory of planned behaviour.

PubMed

Chatzisarantis, Nikos L D; Hagger, Martin S

2008-01-01

Previous research has suggested that the theory of planned behaviour is insufficient in capturing all the antecedents of physical activity participation and that continuation intentions or personality traits may improve the predictive validity of the model. The present study examined the combined effects of continuation intentions and personality traits on health behaviour within the theory of planned behaviour. To examine these effects, 180 university students (N = 180, Male = 87, Female = 93, Age = 19.14 years, SD = 0.94) completed self-report measures of the theory of planned behaviour, personality traits and continuation intentions. After 5 weeks, perceived achievement of behavioural outcomes and actual participation in physical activities were assessed. Results supported discriminant validity between continuation intentions, conscientiousness and extroversion and indicated that perceived achievement of behavioural outcomes and continuation intentions of failure predicted physical activity participation after controlling for personality effects, past behaviour and other variables in the theory of planned behaviour. In addition, results indicated that conscientiousness moderated the effects of continuation intentions of failure on physical activity such that continuation intentions of failure predicted physical activity participation among conscientious and not among less conscientious individuals. These findings suggest that the effects of continuation intentions on health behaviour are contingent on personality characteristics.

The cross education of strength and skill following unilateral strength training in the upper and lower limbs.

PubMed

Green, Lara A; Gabriel, David A

2018-04-18

Cross education is the strength gain or skill improvement transferred to the contralateral limb following unilateral training or practice. The present study examined the transfer of both strength and skill following a strength training program. Forty participants (20M, 20F) completed a 6-week unilateral training program of dominant wrist flexion or dorsiflexion. Strength, force variability, and muscle activity were assessed pre-training, post-training, and following 6-weeks of detraining (retention). Analyses of covariance compared the experimental limb (trained or untrained) to the control (dominant or non-dominant). There were no sex differences in the training response. Cross education of strength at post-training was 6% (p<0.01) in the untrained arm and 13% (p<0.01) in the untrained leg. Contralateral strength continued to increase following detraining to 15% in the arm (p<0.01) and 14% in the leg (p<0.01). There was no difference in strength gains between upper and lower limbs (p>0.05). Cross education of skill (force variability) demonstrated greater improvements in the untrained limbs compared to the control limbs during contractions performed without concurrent feedback. Significant increases in V-wave amplitude (p=0.02) and central activation (p<0.01) were highly correlated with contralateral strength gains. There was no change in agonist amplitude or motor unit firing rates in the untrained limbs (p>0.05). The neuromuscular mechanisms mirrored the force increases at post-training and retention supporting central drive adaptations of cross education. The continued strength increases at retention identified the presence of motor learning in cross education, as confirmed by force variability.

Variability, constraints, and creativity. Shedding light on Claude Monet.

PubMed

Stokes, P D

2001-04-01

Recent experimental research suggests 2 things. The first is that along with learning how to do something, people also learn how variably or differently to continue doing it. The second is that high variability is maintained by constraining, precluding a currently successful, often repetitive solution to a problem. In this view, Claude Monet's habitually high level of variability in painting was acquired during his childhood and early apprenticeship and was maintained throughout his adult career by a continuous series of task constraints imposed by the artist on his own work. For Monet, variability was rewarded and rewarding.

Thermal quench mitigation and current quench control by injection of mixed species shattered pellets in DIII-D

DOE PAGES

Shiraki, D.; Commaux, N.; Baylor, L. R.; ...

2016-06-27

Injection of large shattered pellets composed of variable quantities of the main ion species (deuterium) and high-Z impurities (neon) in the DIII-D tokamak demonstrate control of thermal quench (TQ) and current quench (CQ) properties in mitigated disruptions. As the pellet composition is varied, TQ radiation fractions increase continuously with the quantity of radiating impurity in the pellet, with a corresponding decrease in divertor heating. Post-TQ plasma resistivities increase as a result of the higher radiation fraction, allowing control of current decay timescales based on the pellet composition. Magnetic reconstructions during the CQ show that control of the current decay ratemore » allows continuous variation of the minimum safety factor during the vertically unstable disruption, reducing the halo current fraction and resulting vessel displacement. Both TQ and CQ characteristics are observed to saturate at relatively low quantities of neon, indicating that effective mitigation of disruption loads by shattered pellet injection (SPI) can be achieved with modest impurity quantities, within injection quantities anticipated for ITER. In conclusion, this mixed species SPI technique provides apossible approach for tuning disruption properties to remain within the limited ranges allowed in the ITER design.« less

Thermal quench mitigation and current quench control by injection of mixed species shattered pellets in DIII-D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shiraki, D.; Commaux, N.; Baylor, L. R.

Injection of large shattered pellets composed of variable quantities of the main ion species (deuterium) and high-Z impurities (neon) in the DIII-D tokamak demonstrate control of thermal quench (TQ) and current quench (CQ) properties in mitigated disruptions. As the pellet composition is varied, TQ radiation fractions increase continuously with the quantity of radiating impurity in the pellet, with a corresponding decrease in divertor heating. Post-TQ plasma resistivities increase as a result of the higher radiation fraction, allowing control of current decay timescales based on the pellet composition. Magnetic reconstructions during the CQ show that control of the current decay ratemore » allows continuous variation of the minimum safety factor during the vertically unstable disruption, reducing the halo current fraction and resulting vessel displacement. Both TQ and CQ characteristics are observed to saturate at relatively low quantities of neon, indicating that effective mitigation of disruption loads by shattered pellet injection (SPI) can be achieved with modest impurity quantities, within injection quantities anticipated for ITER. In conclusion, this mixed species SPI technique provides apossible approach for tuning disruption properties to remain within the limited ranges allowed in the ITER design.« less

Thermal quench mitigation and current quench control by injection of mixed species shattered pellets in DIII-D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shiraki, D.; Commaux, N.; Baylor, L. R.

Injection of large shattered pellets composed of variable quantities of the main ion species (deuterium) and high-Z impurities (neon) in the DIII-D tokamak demonstrates control of thermal quench (TQ) and current quench (CQ) properties in mitigated disruptions. As the pellet composition is varied, TQ radiation fractions increase continuously with the quantity of radiating impurity in the pellet, with a corresponding decrease in divertor heating. Post-TQ plasma resistivities increase as a result of the higher radiation fraction, allowing control of current decay timescales based on the pellet composition. Magnetic reconstructions during the CQ show that control of the current decay ratemore » allows continuous variation of the minimum safety factor during the vertically unstable disruption, reducing the halo current fraction and resulting vessel displacement. Both TQ and CQ characteristics are observed to saturate at relatively low quantities of neon, indicating that effective mitigation of disruption loads by shattered pellet injection (SPI) can be achieved with modest impurity quantities, within injection quantities anticipated for ITER. This mixed species SPI technique provides a possible approach for tuning disruption properties to remain within the limited ranges allowed in the ITER design.« less

Generalized Processing Tree Models: Jointly Modeling Discrete and Continuous Variables.

PubMed

Heck, Daniel W; Erdfelder, Edgar; Kieslich, Pascal J

2018-05-24

Multinomial processing tree models assume that discrete cognitive states determine observed response frequencies. Generalized processing tree (GPT) models extend this conceptual framework to continuous variables such as response times, process-tracing measures, or neurophysiological variables. GPT models assume finite-mixture distributions, with weights determined by a processing tree structure, and continuous components modeled by parameterized distributions such as Gaussians with separate or shared parameters across states. We discuss identifiability, parameter estimation, model testing, a modeling syntax, and the improved precision of GPT estimates. Finally, a GPT version of the feature comparison model of semantic categorization is applied to computer-mouse trajectories.

Equivalence between entanglement and the optimal fidelity of continuous variable teleportation.

PubMed

Adesso, Gerardo; Illuminati, Fabrizio

2005-10-07

We devise the optimal form of Gaussian resource states enabling continuous-variable teleportation with maximal fidelity. We show that a nonclassical optimal fidelity of N-user teleportation networks is necessary and sufficient for N-party entangled Gaussian resources, yielding an estimator of multipartite entanglement. The entanglement of teleportation is equivalent to the entanglement of formation in a two-user protocol, and to the localizable entanglement in a multiuser one. Finally, we show that the continuous-variable tangle, quantifying entanglement sharing in three-mode Gaussian states, is defined operationally in terms of the optimal fidelity of a tripartite teleportation network.

NEUTRONIC REACTOR COUNTER METHOD AND SYSTEM

DOEpatents

Graham, C.B.; Spiewak, I.

1960-05-31

An improved method is given for controlling the rate of fission in circulating-fuel neutronic reactors in which the fuel is a homogeneous liquid containing fissionable material and a neutron moderator. A change in the rate of flssion is effected by preferentially retaining apart from the circulating fuel a variable amount of either fissionable material or moderator, thereby varying the concentration of fissionable material in the fuel. In the case of an aqueous fuel solution a portion of the water may be continuously vaporized from the circulating solution and the amount of condensate, or condensate plus make-up water, returned to the solution is varied to control the fission rate.

Quantum-Enhanced Sensing Based on Time Reversal of Nonlinear Dynamics.

PubMed

Linnemann, D; Strobel, H; Muessel, W; Schulz, J; Lewis-Swan, R J; Kheruntsyan, K V; Oberthaler, M K

2016-07-01

We experimentally demonstrate a nonlinear detection scheme exploiting time-reversal dynamics that disentangles continuous variable entangled states for feasible readout. Spin-exchange dynamics of Bose-Einstein condensates is used as the nonlinear mechanism which not only generates entangled states but can also be time reversed by controlled phase imprinting. For demonstration of a quantum-enhanced measurement we construct an active atom SU(1,1) interferometer, where entangled state preparation and nonlinear readout both consist of parametric amplification. This scheme is capable of exhausting the quantum resource by detecting solely mean atom numbers. Controlled nonlinear transformations widen the spectrum of useful entangled states for applied quantum technologies.

Automatic braking system modification for the Advanced Transport Operating Systems (ATOPS) Transportation Systems Research Vehicle (TSRV)

NASA Technical Reports Server (NTRS)

Coogan, J. J.

1986-01-01

Modifications were designed for the B-737-100 Research Aircraft autobrake system hardware of the Advanced Transport Operating Systems (ATOPS) Program at Langley Research Center. These modifications will allow the on-board flight control computer to control the aircraft deceleration after landing to a continuously variable level for the purpose of executing automatic high speed turn-offs from the runway. A bread board version of the proposed modifications was built and tested in simulated stopping conditions. Test results, for various aircraft weights, turnoff speed, winds, and runway conditions show that the turnoff speeds are achieved generally with errors less than 1 ft/sec.

Flatness-based control and Kalman filtering for a continuous-time macroeconomic model

NASA Astrophysics Data System (ADS)

Rigatos, G.; Siano, P.; Ghosh, T.; Busawon, K.; Binns, R.

2017-11-01

The article proposes flatness-based control for a nonlinear macro-economic model of the UK economy. The differential flatness properties of the model are proven. This enables to introduce a transformation (diffeomorphism) of the system's state variables and to express the state-space description of the model in the linear canonical (Brunowsky) form in which both the feedback control and the state estimation problem can be solved. For the linearized equivalent model of the macroeconomic system, stabilizing feedback control can be achieved using pole placement methods. Moreover, to implement stabilizing feedback control of the system by measuring only a subset of its state vector elements the Derivative-free nonlinear Kalman Filter is used. This consists of the Kalman Filter recursion applied on the linearized equivalent model of the financial system and of an inverse transformation that is based again on differential flatness theory. The asymptotic stability properties of the control scheme are confirmed.

Marital breakup in later adulthood and self-rated health: a cross-sectional survey in Switzerland.

PubMed

Knöpfli, Bina; Cullati, Stéphane; Courvoisier, Delphine S; Burton-Jeangros, Claudine; Perrig-Chiello, Pasqualina

2016-04-01

This research examines the impact of relationship status on self-rated health (SRH) by taking into account intrapersonal and social resources. Data stem from a Swiss-based survey of 1355 participants aged 40-65 years. Three groups are compared: continuously married (n = 399), single divorcees (n = 532) and repartnered divorcees (n = 424). Linear regression models are used to examine the predictive role of relationship status on SRH and to investigate the moderating role of intrapersonal and social resources on SRH. Single divorcees show the lowest SRH scores, whereas their repartnered counterparts reported scores comparable to the continuously married-even after controlling for socio-demographic and economic variables. Although single divorcees reported higher levels of loneliness and agreeableness in addition to lower levels of resilience when compared with the other groups, none of these variables had a significant moderation effect on SRH. Our results underscore the positive effect of relationship status on SRH, and contribute new insights on the impact of later-life divorce. Given the growing number of divorcees, related public health challenges are likely to increase.

The Prevention of Surgical Site Infection in Elective Colon Surgery

PubMed Central

Fry, Donald E.

2013-01-01

Infections at the surgical site continue to occur in as many as 20% of elective colon resection cases. Methods to reduce these infections are inconsistently applied. Surgical site infection (SSI) is the result of multiple interactive variables including the inoculum of bacteria that contaminate the site, the virulence of the contaminating microbes, and the local environment at the surgical site. These variables that promote infection are potentially offset by the effectiveness of the host defense. Reduction in the inoculum of bacteria is achieved by appropriate surgical site preparation, systemic preventive antibiotics, and use of mechanical bowel preparation in conjunction with the oral antibiotic bowel preparation. Intraoperative reduction of hematoma, necrotic tissue, foreign bodies, and tissue dead space will reduce infections. Enhancement of the host may be achieved by perioperative supplemental oxygenation, maintenance of normothermia, and glycemic control. These methods require additional research to identify optimum application. Uniform application of currently understood methods and continued research into new methods to reduce microbial contamination and enhancement of host responsiveness can lead to better outcomes. PMID:24455434

Energy conservation through utilization of mechanical energy storage

NASA Astrophysics Data System (ADS)

Eisenhaure, D. B.; Bliamptis, T. E.; Downer, J. R.; Heinemann, P. C.

Potential benefits regarding fuel savings, necessary technology, and evaluation criteria for the development of flywheel-hybrid vehicles are examined. A case study is quoted in which adoption of flywheel-hybrid vehicles in a taxi fleet would result in an increase of 10 mpg average to 32 mpg. Two proposed systems are described, one involving direct engine power to the flywheel and the second regenerating the flywheel from braking energy through a continuously variable transmission. Fuel consumption characteristics are considered the ultimate determinant in the choice of configuration, while material properties and housing shape determine the flywheel speed range. Vehicle losses are characterized and it is expected that a flywheel at 12,000 rpm will experience less than one hp average parasitic power loss. Flywheel storage is suitable for smaller engines because larger engines dominate the power train mass. Areas considered important for further investigation include reliability of an engine run near maximum torque, noise and vibration associated with flywheel operation, start up delays, compatibility of driver controls, integration of normal with regenerative braking systems, and, most importantly, the continuously variable transmission.

Dimensional reduction in sensorimotor systems: A framework for understanding muscle coordination of posture

PubMed Central

Ting, Lena H.

2014-01-01

The simple act of standing up is an important and essential motor behavior that most humans and animals achieve with ease. Yet, maintaining standing balance involves complex sensorimotor transformations that must continually integrate a large array of sensory inputs and coordinate multiple motor outputs to muscles throughout the body. Multiple, redundant local sensory signals are integrated to form an estimate of a few global, task-level variables important to postural control, such as body center of mass position and body orientation with respect to Earth-vertical. Evidence suggests that a limited set of muscle synergies, reflecting preferential sets of muscle activation patterns, are used to move task variables such as center of mass position in a predictable direction following a postural perturbations. We propose a hierarchal feedback control system that allows the nervous system the simplicity of performing goal-directed computations in task-variable space, while maintaining the robustness afforded by redundant sensory and motor systems. We predict that modulation of postural actions occurs in task-variable space, and in the associated transformations between the low-dimensional task-space and high-dimensional sensor and muscle spaces. Development of neuromechanical models that reflect these neural transformations between low and high-dimensional representations will reveal the organizational principles and constraints underlying sensorimotor transformations for balance control, and perhaps motor tasks in general. This framework and accompanying computational models could be used to formulate specific hypotheses about how specific sensory inputs and motor outputs are generated and altered following neural injury, sensory loss, or rehabilitation. PMID:17925254

Sigma metrics used to assess analytical quality of clinical chemistry assays: importance of the allowable total error (TEa) target.

PubMed

Hens, Koen; Berth, Mario; Armbruster, Dave; Westgard, Sten

2014-07-01

Six Sigma metrics were used to assess the analytical quality of automated clinical chemistry and immunoassay tests in a large Belgian clinical laboratory and to explore the importance of the source used for estimation of the allowable total error. Clinical laboratories are continually challenged to maintain analytical quality. However, it is difficult to measure assay quality objectively and quantitatively. The Sigma metric is a single number that estimates quality based on the traditional parameters used in the clinical laboratory: allowable total error (TEa), precision and bias. In this study, Sigma metrics were calculated for 41 clinical chemistry assays for serum and urine on five ARCHITECT c16000 chemistry analyzers. Controls at two analyte concentrations were tested and Sigma metrics were calculated using three different TEa targets (Ricos biological variability, CLIA, and RiliBÄK). Sigma metrics varied with analyte concentration, the TEa target, and between/among analyzers. Sigma values identified those assays that are analytically robust and require minimal quality control rules and those that exhibit more variability and require more complex rules. The analyzer to analyzer variability was assessed on the basis of Sigma metrics. Six Sigma is a more efficient way to control quality, but the lack of TEa targets for many analytes and the sometimes inconsistent TEa targets from different sources are important variables for the interpretation and the application of Sigma metrics in a routine clinical laboratory. Sigma metrics are a valuable means of comparing the analytical quality of two or more analyzers to ensure the comparability of patient test results.

Maximum power point tracking algorithm based on sliding mode and fuzzy logic for photovoltaic sources under variable environmental conditions

NASA Astrophysics Data System (ADS)

Atik, L.; Petit, P.; Sawicki, J. P.; Ternifi, Z. T.; Bachir, G.; Della, M.; Aillerie, M.

2017-02-01

Solar panels have a nonlinear voltage-current characteristic, with a distinct maximum power point (MPP), which depends on the environmental factors, such as temperature and irradiation. In order to continuously harvest maximum power from the solar panels, they have to operate at their MPP despite the inevitable changes in the environment. Various methods for maximum power point tracking (MPPT) were developed and finally implemented in solar power electronic controllers to increase the efficiency in the electricity production originate from renewables. In this paper we compare using Matlab tools Simulink, two different MPP tracking methods, which are, fuzzy logic control (FL) and sliding mode control (SMC), considering their efficiency in solar energy production.

Automatic Gain Control in Compact Spectrometers.

PubMed

Protopopov, Vladimir

2016-03-01

An image intensifier installed in the optical path of a compact spectrometer may act not only as a fast gating unit, which is widely used for time-resolved measurements, but also as a variable attenuator-amplifier in a continuous wave mode. This opens the possibility of an automatic gain control, a new feature in spectroscopy. With it, the user is relieved from the necessity to manually adjust signal level at a certain value that it is done automatically by means of an electronic feedback loop. It is even more important that automatic gain control is done without changing exposure time, which is an additional benefit in time-resolved experiments. The concept, algorithm, design considerations, and experimental results are presented. © The Author(s) 2016.

[Survival strategy of photosynthetic organisms. 1. Variability of the extent of light-harvesting pigment aggregation as a structural factor optimizing the function of oligomeric photosynthetic antenna. Model calculations].

PubMed

Fetisova, Z G

2004-01-01

In accordance with our concept of rigorous optimization of photosynthetic machinery by a functional criterion, this series of papers continues purposeful search in natural photosynthetic units (PSU) for the basic principles of their organization that we predicted theoretically for optimal model light-harvesting systems. This approach allowed us to determine the basic principles for the organization of a PSU of any fixed size. This series of papers deals with the problem of structural optimization of light-harvesting antenna of variable size controlled in vivo by the light intensity during the growth of organisms, which accentuates the problem of antenna structure optimization because optimization requirements become more stringent as the PSU increases in size. In this work, using mathematical modeling for the functioning of natural PSUs, we have shown that the aggregation of pigments of model light-harvesting antenna, being one of universal optimizing factors, furthermore allows controlling the antenna efficiency if the extent of pigment aggregation is a variable parameter. In this case, the efficiency of antenna increases with the size of the elementary antenna aggregate, thus ensuring the high efficiency of the PSU irrespective of its size; i.e., variation in the extent of pigment aggregation controlled by the size of light-harvesting antenna is biologically expedient.

Optical microsensor for continuous glucose measurements in interstitial fluid

NASA Astrophysics Data System (ADS)

Olesberg, Jonathon T.; Cao, Chuanshun; Yager, Jeffrey R.; Prineas, John P.; Coretsopoulos, Chris; Arnold, Mark A.; Olafsen, Linda J.; Santilli, Michael

2006-02-01

Tight control of blood glucose levels has been shown to dramatically reduce the long-term complications of diabetes. Current invasive technology for monitoring glucose levels is effective but underutilized by people with diabetes because of the pain of repeated finger-sticks, the inconvenience of handling samples of blood, and the cost of reagent strips. A continuous glucose sensor coupled with an insulin delivery system could provide closed-loop glucose control without the need for discrete sampling or user intervention. We describe an optical glucose microsensor based on absorption spectroscopy in interstitial fluid that can potentially be implanted to provide continuous glucose readings. Light from a GaInAsSb LED in the 2.2-2.4 μm wavelength range is passed through a sample of interstitial fluid and a linear variable filter before being detected by an uncooled, 32-element GaInAsSb detector array. Spectral resolution is provided by the linear variable filter, which has a 10 nm band pass and a center wavelength that varies from 2.18-2.38 μm (4600-4200 cm -1) over the length of the detector array. The sensor assembly is a monolithic design requiring no coupling optics. In the present system, the LED running with 100 mA of drive current delivers 20 nW of power to each of the detector pixels, which have a noise-equivalent-power of 3 pW/Hz 1/2. This is sufficient to provide a signal-to-noise ratio of 4500 Hz 1/2 under detector-noise limited conditions. This signal-to-noise ratio corresponds to a spectral noise level less than 10 μAU for a five minute integration, which should be sufficient for sub-millimolar glucose detection.

Heart Rate Variability in Obstetricians Working 14-Hour Call Compared to 24-Hour Call in Labour and Delivery.

PubMed

Thurman, Robin H; Yoon, Eugene; Murphy, Kellie E; Windrim, Rory; Farrugia, M Michéle

2017-12-01

Obstetricians have stressful and demanding jobs that may impact their health. A physiological measurement of cardiac function which varies with stress is heart rate variability (HRV). By measuring the cyclic variations in R-R intervals, or beat-to-beat differences, HRV reflects the continuous interplay of the controlling forces in the autonomic nervous system. Studies have shown HRV to be reduced during periods of work-induced stress, including 24-hour shifts. Our study aimed to determine if there was a correlation between length of shift worked and HRV. We hypothesised that working for a full 24-hour period is more stressful than a shorter, nighttime-only period, and HRV analyses were used to measure this objectively. Obstetricians wore an HRV monitor for 24 hours during both a regular day followed by a 14-hour night shift and a continuous 24-hour shift in labour and delivery. The 24-hour samples were analysed using standard HRV measurements. HRV measurements obtained from each physician were then compared according to shift type, with each physician acting as his or her own comparator. There were no statistically significant differences in the most important measures of HRV between 24-hour periods which included either a 14-hour overnight shift or a continuous 24-hour shift on labour and delivery. We found no significant differences in key HRV measures in obstetricians working 14 hours versus 24 hours in labour and delivery. An anecdotal increase in physician awareness of his/her own health related to working conditions was noted during the study. Future studies should attempt to control for the hours prior to a night shift, assess associated endocrine variations, and focus upon HRV in the post-shift period. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

Autonomous Control of Space Nuclear Reactors

NASA Technical Reports Server (NTRS)

Merk, John

2013-01-01

Nuclear reactors to support future robotic and manned missions impose new and innovative technological requirements for their control and protection instrumentation. Long-duration surface missions necessitate reliable autonomous operation, and manned missions impose added requirements for failsafe reactor protection. There is a need for an advanced instrumentation and control system for space-nuclear reactors that addresses both aspects of autonomous operation and safety. The Reactor Instrumentation and Control System (RICS) consists of two functionally independent systems: the Reactor Protection System (RPS) and the Supervision and Control System (SCS). Through these two systems, the RICS both supervises and controls a nuclear reactor during normal operational states, as well as monitors the operation of the reactor and, upon sensing a system anomaly, automatically takes the appropriate actions to prevent an unsafe or potentially unsafe condition from occurring. The RPS encompasses all electrical and mechanical devices and circuitry, from sensors to actuation device output terminals. The SCS contains a comprehensive data acquisition system to measure continuously different groups of variables consisting of primary measurement elements, transmitters, or conditioning modules. These reactor control variables can be categorized into two groups: those directly related to the behavior of the core (known as nuclear variables) and those related to secondary systems (known as process variables). Reliable closed-loop reactor control is achieved by processing the acquired variables and actuating the appropriate device drivers to maintain the reactor in a safe operating state. The SCS must prevent a deviation from the reactor nominal conditions by managing limitation functions in order to avoid RPS actions. The RICS has four identical redundancies that comply with physical separation, electrical isolation, and functional independence. This architecture complies with the safety requirements of a nuclear reactor and provides high availability to the host system. The RICS is intended to interface with a host computer (the computer of the spacecraft where the reactor is mounted). The RICS leverages the safety features inherent in Earth-based reactors and also integrates the wide range neutron detector (WRND). A neutron detector provides the input that allows the RICS to do its job. The RICS is based on proven technology currently in use at a nuclear research facility. In its most basic form, the RICS is a ruggedized, compact data-acquisition and control system that could be adapted to support a wide variety of harsh environments. As such, the RICS could be a useful instrument outside the scope of a nuclear reactor, including military applications where failsafe data acquisition and control is required with stringent size, weight, and power constraints.

The Mediating Roles of Internal Context Variables in the Relationship between Distributed Leadership Perceptions and Continuous Change Behaviours of Public School Teachers

ERIC Educational Resources Information Center

Kondakci, Yasar; Zayim, Merve; Beycioglu, Kadir; Sincar, Mehmet; Ugurlu, Celal T

2016-01-01

This study aims at building a theoretical base for continuous change in education and using this base to test the mediating roles of two key contextual variables, knowledge sharing and trust, in the relationship between the distributed leadership perceptions and continuous change behaviours of teachers. Data were collected from 687 public school…

Optimizing Multi-Product Multi-Constraint Inventory Control Systems with Stochastic Replenishments

NASA Astrophysics Data System (ADS)

Allah Taleizadeh, Ata; Aryanezhad, Mir-Bahador; Niaki, Seyed Taghi Akhavan

Multi-periodic inventory control problems are mainly studied employing two assumptions. The first is the continuous review, where depending on the inventory level orders can happen at any time and the other is the periodic review, where orders can only happen at the beginning of each period. In this study, we relax these assumptions and assume that the periodic replenishments are stochastic in nature. Furthermore, we assume that the periods between two replenishments are independent and identically random variables. For the problem at hand, the decision variables are of integer-type and there are two kinds of space and service level constraints for each product. We develop a model of the problem in which a combination of back-order and lost-sales are considered for the shortages. Then, we show that the model is of an integer-nonlinear-programming type and in order to solve it, a search algorithm can be utilized. We employ a simulated annealing approach and provide a numerical example to demonstrate the applicability of the proposed methodology.

Stationarity of the Tropical Pacific Teleconnection to North America in CMIP5 PMIP3 Model Simulations

NASA Technical Reports Server (NTRS)

Coats, Sloan; Smerdon, Jason E.; Cook, Benjamin I.; Seager, Richard

2013-01-01

The temporal stationarity of the teleconnection between the tropical Pacific Ocean and North America (NA) is analyzed in atmosphere-only, and coupled last-millennium, historical, and control runs from the Coupled Model Intercomparison Project Phase 5 data archive. The teleconnection, defined as the correlation between December-January-February (DJF) tropical Pacific sea surface temperatures (SSTs) and DJF 200 mb geopotential height, is found to be nonstationary on multidecadal timescales. There are significant changes in the spatial features of the teleconnection over NA in continuous 56-year segments of the last millennium and control simulations. Analysis of atmosphere-only simulations forced with observed SSTs indicates that atmospheric noise cannot account for the temporal variability of the teleconnection, which instead is likely explained by the strength of, and multidecadal changes in, tropical Pacific Ocean variability. These results have implications for teleconnection-based analyses of model fidelity in simulating precipitation, as well as any reconstruction and forecasting efforts that assume stationarity of the observed teleconnection.

Dearth by a Thousand Cuts? Accounting for Gender Differences in Top-Ranked Publication Rates in Social Psychology.

PubMed

Cikara, Mina; Rudman, Laurie; Fiske, Susan

2012-01-01

Publication in the Journal of Personality and Social Psychology , a flagship indicator of scientific prestige, shows dramatic gender disparities. A bibliometric analysis included yoked-control authors matched for Ph.D. prestige and cohort. Though women publish less, at slower annual rates, they are more cited in handbooks and textbooks per JPSP -article-published. No gender differences emerged on variables reflecting differential qualifications. Many factors explain gender discrepancy in productivity. Among top publishers, per-year rate and first authorship especially differ by gender; rate uniquely predicts top-male productivity, whereas career-length uniquely predicts top-female productivity. Among men, across top-publishers and controls, productivity correlates uniquely with editorial negotiating and being married. For women, no personal variables predict productivity. A separate inquiry shows tiny gender differences in acceptance rates per JPSP article submitted; discrimination would be a small-but-plausible contributor, absent independent indicators of manuscript quality. Recent productivity rates mirror earlier gender disparities, suggesting gender gaps will continue.

Greater diet quality is associated with more optimal glycemic control in a longitudinal study of youth with type 1 diabetes.

PubMed

Nansel, Tonja R; Lipsky, Leah M; Liu, Aiyi

2016-07-01

Despite the centrality of nutrition in the management of type 1 diabetes, the association of diet quality and macronutrient distribution with glycemic control is ambiguous. This study examined longitudinally the association of dietary intake with multiple indicators of glycemic control in youth with type 1 diabetes participating in a behavioral nutrition intervention study. Participants in a randomized clinical trial of a behavioral nutrition intervention [n = 136; mean ± SD age: 12.8 ± 2.6 y; glycated hemoglobin (HbA1c): 8.1% ± 1.0%; 69.1% using an insulin pump] completed 3-d diet records at baseline and months 3, 6, 9, 12, and 18; masked continuous glucose monitoring (CGM) data were obtained concurrently with the use of the Medtronic iPro CGM system. HbA1c was obtained every 3 mo; 1,5-anhydroglucitol was obtained every 6 mo. Linear mixed-effects regression models estimated associations of time-varying dietary intake variables with time-varying glycemic control indicators, controlling for age, height, weight, sex, Tanner stage, diabetes duration, regimen, frequency of blood glucose monitoring, physical activity, and treatment assignment. HbA1c was associated inversely with carbohydrate and natural sugar, and positively with protein and unsaturated fat. 1,5-Anhydroglucitol was associated positively with fiber intake and natural sugar. Greater glycemic control as indicated by ≥1 CGM variable was associated with higher Healthy Eating Index-2005, whole plant food density, fiber, carbohydrate, and natural sugar and lower glycemic index and unsaturated fat. Both overall diet quality and macronutrient distribution were associated with more optimal glycemic control. Associations were more consistent for CGM variables obtained concurrently with dietary intake than for biomarkers of longer-term glycemic control. These findings suggest that glycemic control may be improved by increasing intake of high-fiber, low glycemic-index, carbohydrate-containing foods. This trial was registered at clinicaltrials.gov as NCT00999375. © 2016 American Society for Nutrition.

Utility of different glycemic control metrics for optimizing management of diabetes.

PubMed

Kohnert, Klaus-Dieter; Heinke, Peter; Vogt, Lutz; Salzsieder, Eckhard

2015-02-15

The benchmark for assessing quality of long-term glycemic control and adjustment of therapy is currently glycated hemoglobin (HbA1c). Despite its importance as an indicator for the development of diabetic complications, recent studies have revealed that this metric has some limitations; it conveys a rather complex message, which has to be taken into consideration for diabetes screening and treatment. On the basis of recent clinical trials, the relationship between HbA1c and cardiovascular outcomes in long-standing diabetes has been called into question. It becomes obvious that other surrogate and biomarkers are needed to better predict cardiovascular diabetes complications and assess efficiency of therapy. Glycated albumin, fructosamin, and 1,5-anhydroglucitol have received growing interest as alternative markers of glycemic control. In addition to measures of hyperglycemia, advanced glucose monitoring methods became available. An indispensible adjunct to HbA1c in routine diabetes care is self-monitoring of blood glucose. This monitoring method is now widely used, as it provides immediate feedback to patients on short-term changes, involving fasting, preprandial, and postprandial glucose levels. Beyond the traditional metrics, glycemic variability has been identified as a predictor of hypoglycemia, and it might also be implicated in the pathogenesis of vascular diabetes complications. Assessment of glycemic variability is thus important, but exact quantification requires frequently sampled glucose measurements. In order to optimize diabetes treatment, there is a need for both key metrics of glycemic control on a day-to-day basis and for more advanced, user-friendly monitoring methods. In addition to traditional discontinuous glucose testing, continuous glucose sensing has become a useful tool to reveal insufficient glycemic management. This new technology is particularly effective in patients with complicated diabetes and provides the opportunity to characterize glucose dynamics. Several continuous glucose monitoring (CGM) systems, which have shown usefulness in clinical practice, are presently on the market. They can broadly be divided into systems providing retrospective or real-time information on glucose patterns. The widespread clinical application of CGM is still hampered by the lack of generally accepted measures for assessment of glucose profiles and standardized reporting of glucose data. In this article, we will discuss advantages and limitations of various metrics for glycemic control as well as possibilities for evaluation of glucose data with the special focus on glycemic variability and application of CGM to improve individual diabetes management.

PSC algorithm description

NASA Technical Reports Server (NTRS)

Nobbs, Steven G.

1995-01-01

An overview of the performance seeking control (PSC) algorithm and details of the important components of the algorithm are given. The onboard propulsion system models, the linear programming optimization, and engine control interface are described. The PSC algorithm receives input from various computers on the aircraft including the digital flight computer, digital engine control, and electronic inlet control. The PSC algorithm contains compact models of the propulsion system including the inlet, engine, and nozzle. The models compute propulsion system parameters, such as inlet drag and fan stall margin, which are not directly measurable in flight. The compact models also compute sensitivities of the propulsion system parameters to change in control variables. The engine model consists of a linear steady state variable model (SSVM) and a nonlinear model. The SSVM is updated with efficiency factors calculated in the engine model update logic, or Kalman filter. The efficiency factors are used to adjust the SSVM to match the actual engine. The propulsion system models are mathematically integrated to form an overall propulsion system model. The propulsion system model is then optimized using a linear programming optimization scheme. The goal of the optimization is determined from the selected PSC mode of operation. The resulting trims are used to compute a new operating point about which the optimization process is repeated. This process is continued until an overall (global) optimum is reached before applying the trims to the controllers.

Simulation and qualitative analysis of glucose variability, mean glucose, and hypoglycemia after subcutaneous insulin therapy for stress hyperglycemia.

PubMed

Strilka, Richard J; Stull, Mamie C; Clemens, Michael S; McCaver, Stewart C; Armen, Scott B

2016-01-27

The critically ill can have persistent dysglycemia during the "subacute" recovery phase of their illness because of altered gene expression; it is also not uncommon for these patients to receive continuous enteral nutrition during this time. The optimal short-acting subcutaneous insulin therapy that should be used in this clinical scenario, however, is unknown. Our aim was to conduct a qualitative numerical study of the glucose-insulin dynamics within this patient population to answer the above question. This analysis may help clinicians design a relevant clinical trial. Eight virtual patients with stress hyperglycemia were simulated by means of a mathematical model. Each virtual patient had a different combination of insulin resistance and insulin deficiency that defined their unique stress hyperglycemia state; the rate of gluconeogenesis was also doubled. The patients received 25 injections of subcutaneous regular or Lispro insulin (0-6 U) with 3 rates of continuous nutrition. The main outcome measurements were the change in mean glucose concentration, the change in glucose variability, and hypoglycemic episodes. These end points were interpreted by how the ultradian oscillations of glucose concentration were affected by each insulin preparation. Subcutaneous regular insulin lowered both mean glucose concentrations and glucose variability in a linear fashion. No hypoglycemic episodes were noted. Although subcutaneous Lispro insulin lowered mean glucose concentrations, glucose variability increased in a nonlinear fashion. In patients with high insulin resistance and nutrition at goal, "rebound hyperglycemia" was noted after the insulin analog was rapidly metabolized. When the nutritional source was removed, hypoglycemia tended to occur at higher Lispro insulin doses. Finally, patients with severe insulin resistance seemed the most sensitive to insulin concentration changes. Subcutaneous regular insulin consistently lowered mean glucose concentrations and glucose variability; its linear dose-response curve rendered the preparation better suited for a sliding-scale protocol. The longer duration of action of subcutaneous regular insulin resulted in better glycemic-control metrics for patients who were continuously postprandial. Clinical trials are needed to examine whether these numerical results represent the glucose-insulin dynamics that occur in intensive care units; if present, their clinical effects should be evaluated.

Concurrent generation of multivariate mixed data with variables of dissimilar types.

PubMed

Amatya, Anup; Demirtas, Hakan

2016-01-01

Data sets originating from wide range of research studies are composed of multiple variables that are correlated and of dissimilar types, primarily of count, binary/ordinal and continuous attributes. The present paper builds on the previous works on multivariate data generation and develops a framework for generating multivariate mixed data with a pre-specified correlation matrix. The generated data consist of components that are marginally count, binary, ordinal and continuous, where the count and continuous variables follow the generalized Poisson and normal distributions, respectively. The use of the generalized Poisson distribution provides a flexible mechanism which allows under- and over-dispersed count variables generally encountered in practice. A step-by-step algorithm is provided and its performance is evaluated using simulated and real-data scenarios.

Effects of a cognitive dual task on variability and local dynamic stability in sustained repetitive arm movements using principal component analysis: a pilot study.

PubMed

Longo, Alessia; Federolf, Peter; Haid, Thomas; Meulenbroek, Ruud

2018-06-01

In many daily jobs, repetitive arm movements are performed for extended periods of time under continuous cognitive demands. Even highly monotonous tasks exhibit an inherent motor variability and subtle fluctuations in movement stability. Variability and stability are different aspects of system dynamics, whose magnitude may be further affected by a cognitive load. Thus, the aim of the study was to explore and compare the effects of a cognitive dual task on the variability and local dynamic stability in a repetitive bimanual task. Thirteen healthy volunteers performed the repetitive motor task with and without a concurrent cognitive task of counting aloud backwards in multiples of three. Upper-body 3D kinematics were collected and postural reconfigurations-the variability related to the volunteer's postural change-were determined through a principal component analysis-based procedure. Subsequently, the most salient component was selected for the analysis of (1) cycle-to-cycle spatial and temporal variability, and (2) local dynamic stability as reflected by the largest Lyapunov exponent. Finally, end-point variability was evaluated as a control measure. The dual cognitive task proved to increase the temporal variability and reduce the local dynamic stability, marginally decrease endpoint variability, and substantially lower the incidence of postural reconfigurations. Particularly, the latter effect is considered to be relevant for the prevention of work-related musculoskeletal disorders since reduced variability in sustained repetitive tasks might increase the risk of overuse injuries.

Design and dynamic simulation of a fixed pitch 56 kW wind turbine drive train with a continuously variable transmission

NASA Technical Reports Server (NTRS)

Gallo, C.; Kasuba, R.; Pintz, A.; Spring, J.

1986-01-01

The dynamic analysis of a horizontal axis fixed pitch wind turbine generator (WTG) rated at 56 kW is discussed. A mechanical Continuously Variable Transmission (CVT) was incorporated in the drive train to provide variable speed operation capability. One goal of the dynamic analysis was to determine if variable speed operation, by means of a mechanical CVT, is capable of capturing the transient power in the WTG/wind environment. Another goal was to determine the extent of power regulation possible with CVT operation.

Insulin pump patient characteristics and glucose control in the hospitalized setting.

PubMed

Kannan, Subramanian; Satra, Ankita; Calogeras, Ellen; Lock, Patricia; Lansang, M Cecilia

2014-05-01

Patients' knowledge of their insulin pumps and glucose control during hospitalization has not been studied. The aim was to study the determinants of glycemic control in patients using continuous subcutaneous insulin infusion (CSII) in the hospital. Three groups of patients were identified: those who did not need any inpatient education and continued on CSII (gorup A), those who received education then continued on CSII (group B), and those for whom CSII was not appropriate and were treated with multiple daily insulin injections (gorup C). We compared the measures of glycemic control between the 3 groups and analyzed which variables impacted glucose control. There were 50 patients, with 51 hospital admissions, 57% males, mean age 48 ± 13 years, 86% had type 1 diabetes (T1DM). The mean DM duration was 26 ± 14 years, mean duration of CSII use was 8.7 ± 6 years, and mean HbA1c was 7.6 ± 1.4%. The mean duration of hospital stay was 5.6 ± 4.6 days. Mean blood glucose (BG) and frequency of hyperglycemia and hypoglycemic events among the 3 groups adjusted for their duration of hospital stay were not statistically different. None of the patients developed diabetic ketoacidosis while using their pump. Stepwise multivariate analysis revealed knowledge of hypoglycemia correction was the single most important predictor of mean BG (P < .001). Patients who received inpatient education performed similarly to patients who did not need inpatient education. Patients who receive inpatient education on CSII fare similar as patients who did not require inpatient education. © 2014 Diabetes Technology Society.

Voluntary presetting of the vestibular ocular reflex permits gaze stabilization despite perturbation of fast head movements

NASA Technical Reports Server (NTRS)

Zangemeister, Wolfgang H.

1989-01-01

Normal subjects are able to change voluntarily and continuously their head-eye latency together with their compensatory eye movement gain. A continuous spectrum of intent-latency modes of the subject's coordinated gaze through verbal feedback could be demonstrated. It was also demonstrated that the intent to counteract any perturbation of head-eye movement, i.e., the mental set, permitted the subjects to manipulate consciously their vestibular ocular reflex (VOR) gain. From the data, it is inferred that the VOR is always on. It may be, however, variably suppressed by higher cortical control. With appropriate training, head-mounted displays should permit an easy VOR presetting that leads to image stabilization, perhaps together with a decrease of possible misjudgements.

Instrumenting an upland research catchment in Canterbury, New Zealand to study controls on variability of soil moisture, shallow groundwater and streamflow

NASA Astrophysics Data System (ADS)

McMillan, Hilary; Srinivasan, Ms

2015-04-01

Hydrologists recognise the importance of vertical drainage and deep flow paths in runoff generation, even in headwater catchments. Both soil and groundwater stores are highly variable over multiple scales, and the distribution of water has a strong control on flow rates and timing. In this study, we instrumented an upland headwater catchment in New Zealand to measure the temporal and spatial variation in unsaturated and saturated-zone responses. In NZ, upland catchments are the source of much of the water used in lowland agriculture, but the hydrology of such catchments and their role in water partitioning, storage and transport is poorly understood. The study area is the Langs Gully catchment in the North Branch of the Waipara River, Canterbury: this catchment was chosen to be representative of the foothills environment, with lightly managed dryland pasture and native Matagouri shrub vegetation cover. Over a period of 16 months we measured continuous soil moisture at 32 locations and near-surface water table (< 2 m) at 14 locations, as well as measuring flow at 3 stream gauges. The distributed measurement sites were located to allow comparisons between North and South facing locations, near-stream versus hillslope locations, and convergent versus divergent hillslopes. We found that temporal variability is strongly controlled by the climatic seasonal cycle, for both soil moisture and water table, and for both the mean and extremes of their distributions. Groundwater is a larger water storage component than soil moisture, and the difference increases with catchment wetness. The spatial standard deviation of both soil moisture and groundwater is larger in winter than in summer. It peaks during rainfall events due to partial saturation of the catchment, and also rises in spring as different locations dry out at different rates. The most important controls on spatial variability are aspect and distance from stream. South-facing and near-stream locations have higher water tables and more, larger soil moisture wetting events. Typical hydrological models do not explicitly account for aspect, but our results suggest that it is an important factor in hillslope runoff generation. Co-measurement of soil moisture and water table level allowed us to identify interrelationships between the two. Locations where water tables peaked closest to the surface had consistently wetter soils and higher water tables. These wetter sites were the same across seasons. However, temporary patterns of strong soil moisture response to summer storms did not correspond to the wetter sites. Total catchment spatial variability is composed of multiple variability sources, and the dominant type is sensitive to those stores that are close to a threshold such as field capacity or saturation. Therefore, we classified spatial variability as 'summer mode' or 'winter mode'. In summer mode, variability is controlled by shallow processes e.g. interactions of water with soils and vegetation. In winter mode, variability is controlled by deeper processes e.g. groundwater movement and bypass flow. Double flow peaks observed during some events show the direct impact of groundwater variability on runoff generation. Our results suggest that emergent catchment behaviour depends on the combination of these multiple, time varying components of variability.

Computer Simulations and Literature Survey of Continuously Variable Transmissions for Use in Buses

DOT National Transportation Integrated Search

1981-12-01

Numerous studies have been conducted on the concept of flywheel energy storage for buses. Flywheel systems require a continuously variable transmission (CVT) of some type to transmit power between the flywheel and the drive wheels. However, a CVT can...

Implementation of continuous-variable quantum key distribution with composable and one-sided-device-independent security against coherent attacks.

PubMed

Gehring, Tobias; Händchen, Vitus; Duhme, Jörg; Furrer, Fabian; Franz, Torsten; Pacher, Christoph; Werner, Reinhard F; Schnabel, Roman

2015-10-30

Secret communication over public channels is one of the central pillars of a modern information society. Using quantum key distribution this is achieved without relying on the hardness of mathematical problems, which might be compromised by improved algorithms or by future quantum computers. State-of-the-art quantum key distribution requires composable security against coherent attacks for a finite number of distributed quantum states as well as robustness against implementation side channels. Here we present an implementation of continuous-variable quantum key distribution satisfying these requirements. Our implementation is based on the distribution of continuous-variable Einstein-Podolsky-Rosen entangled light. It is one-sided device independent, which means the security of the generated key is independent of any memoryfree attacks on the remote detector. Since continuous-variable encoding is compatible with conventional optical communication technology, our work is a step towards practical implementations of quantum key distribution with state-of-the-art security based solely on telecom components.

Implementation of continuous-variable quantum key distribution with composable and one-sided-device-independent security against coherent attacks

PubMed Central

Gehring, Tobias; Händchen, Vitus; Duhme, Jörg; Furrer, Fabian; Franz, Torsten; Pacher, Christoph; Werner, Reinhard F.; Schnabel, Roman

2015-01-01

Secret communication over public channels is one of the central pillars of a modern information society. Using quantum key distribution this is achieved without relying on the hardness of mathematical problems, which might be compromised by improved algorithms or by future quantum computers. State-of-the-art quantum key distribution requires composable security against coherent attacks for a finite number of distributed quantum states as well as robustness against implementation side channels. Here we present an implementation of continuous-variable quantum key distribution satisfying these requirements. Our implementation is based on the distribution of continuous-variable Einstein–Podolsky–Rosen entangled light. It is one-sided device independent, which means the security of the generated key is independent of any memoryfree attacks on the remote detector. Since continuous-variable encoding is compatible with conventional optical communication technology, our work is a step towards practical implementations of quantum key distribution with state-of-the-art security based solely on telecom components. PMID:26514280

Strategies for Voltage Control and Transient Stability Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hiskens, Ian A.

As wind generation grows, its influence on power system performance will becoming increasingly noticeable. Wind generation di ffers from traditional forms of generation in numerous ways though, motivating the need to reconsider the usual approaches to power system assessment and performance enhancement. The project has investigated the impact of wind generation on transient stability and voltage control, identifying and addressing issues at three distinct levels of the power system: 1) at the device level, the physical characteristics of wind turbine generators (WTGs) are quite unlike those of synchronous machines, 2) at the wind-farm level, the provision of reactive support ismore » achieved through coordination of numerous dissimilar devices, rather than straightforward generator control, and 3) from a systems perspective, the location of wind-farms on the sub-transmission network, coupled with the variability inherent in their power output, can cause complex voltage control issues. The project has sought to develop a thorough understanding of the dynamic behaviour of type-3 WTGs, and in particular the WECC generic model. The behaviour of such models is governed by interactions between the continuous dynamics of state variables and discrete events associated with limits. It was shown that these interactions can be quite complex, and may lead to switching deadlock that prevents continuation of the trajectory. Switching hysteresis was proposed for eliminating deadlock situations. Various type-3 WTG models include control blocks that duplicate integrators. It was shown that this leads to non-uniqueness in the conditions governing steady-state, and may result in pre- and post-disturbance equilibria not coinciding. It also gives rise to a zero eigenvalue in the linearized WTG model. In order to eliminate the anomalous behaviour revealed through this investigation, WECC has now released a new generic model for type-3 WTGs. Wind-farms typically incorporate a variety of voltage control equipment including tapchanging transformers, switched capacitors, SVCs, STATCOMs and the WTGs themselves. The project has considered the coordinated control of this equipment, and has addressed a range of issues that arise in wind-farm operation. The first concerns the ability of WTGs to meet reactive power requirements when voltage saturation in the collector network restricts the reactive power availability of individual generators. Secondly, dynamic interactions between voltage regulating devices have been investigated. It was found that under certain realistic conditions, tap-changing transformers may exhibit instability. In order to meet cost, maintenance, fault tolerance and other requirements, it is desirable for voltage control equipment to be treated as an integrated system rather than as independent devices. The resulting high-level scheduling of wind-farm reactive support has been investigated. In addressing this control problem, several forms of future information were considered, including exact future knowledge and stochastic predictions. Deterministic and Stochastic Dynamic Programming techniques were used in the development of control algorithms. The results demonstrated that while exact future knowledge is very useful, simple prediction methods yield little bene fit. The integration of inherently variable wind generation into weak grids, particularly subtransmission networks that are characterized by low X=R ratios, aff ects bus voltages, regulating devices and line flows. The meshed structure of these networks adds to the complexity, especially when wind generation is distributed across multiple nodes. A range of techniques have been considered for analyzing the impact of wind variability on weak grids. Sensitivity analysis, based on the power-flow Jacobian, was used to highlight sections of a system that are most severely a ffected by wind-power variations. A continuation power flow was used to determine parameter changes that reduce the impact of wind-power variability. It was also used to explore interactions between multiple wind-farms. Furthermore, these tools have been used to examine the impact of wind injection on transformer tap operation in subtransmission networks. The results of a tap operation simulation study show that voltage regulation at wind injection nodes increases tap change operations. The tradeo ff between local voltage regulation and tap change frequency is fundamentally important in optimizing the size of reactive compensation used for voltage regulation at wind injection nodes. Line congestion arising as a consequence of variable patterns of wind-power production has also been investigated. Two optimization problems have been formulated, based respectively on the DC and AC power flow models, for identifying vulnerable line segments. The DC optimization is computationally more e fficient, whereas the AC sensitivity-based optimization provides greater accuracy.« less

Multiscale perspectives of fire, climate and humans in western North America and the Jemez Mountains, USA

USGS Publications Warehouse

Swetnam, Thomas W.; Farella, Joshua; Roos, Christopher I.; Liebmann, Matthew J.; Falk, Donald A.; Allen, Craig D.

2016-01-01

Interannual climate variations have been important drivers of wildfire occurrence in ponderosa pine forests across western North America for at least 400 years, but at finer scales of mountain ranges and landscapes human land uses sometimes over-rode climate influences. We reconstruct and analyse effects of high human population densities in forests of the Jemez Mountains, New Mexico from ca 1300 CE to Present. Prior to the 1680 Pueblo Revolt, human land uses reduced the occurrence of widespread fires while simultaneously adding more ignitions resulting in many small-extent fires. During the 18th and 19th centuries, wet/dry oscillations and their effects on fuels dynamics controlled widespread fire occurrence. In the late 19th century, intensive livestock grazing disrupted fuels continuity and fire spread and then active fire suppression maintained the absence of widespread surface fires during most of the 20th century. The abundance and continuity of fuels is the most important controlling variable in fire regimes of these semi-arid forests. Reduction of widespread fires owing to reduction of fuel continuity emerges as a hallmark of extensive human impacts on past forests and fire regimes.

Cognitive Improvement of Attention and Inhibition in the Late Afternoon in Children With Attention-Deficit Hyperactivity Disorder (ADHD) Treated With Osmotic-Release Oral System Methylphenidate.

PubMed

Slama, Hichem; Fery, Patrick; Verheulpen, Denis; Vanzeveren, Nathalie; Van Bogaert, Patrick

2015-07-01

Long-acting medications have been developed and approved for use in the treatment of attention-deficit hyperactivity disorder (ADHD). These compounds are intended to optimize and maintain symptoms control throughout the day. We tested prolonged effects of osmotic-release oral system methylphenidate on both attention and inhibition, in the late afternoon. A double-blind, randomized, placebo-controlled study was conducted in 36 boys (7-12 years) with ADHD and 40 typically developing children. The ADHD children received an individualized dose of placebo or osmotic-release oral system methylphenidate. They were tested about 8 hours after taking with 2 continuous performance tests (continuous performance test-X [CPT-X] and continuous performance test-AX [CPT-AX]) and a counting Stroop. A positive effect of osmotic-release oral system methylphenidate was present in CPT-AX with faster and less variable reaction times under osmotic-release oral system methylphenidate than under placebo, and no difference with typically developing children. In the counting Stroop, we found a decreased interference with osmotic-release oral system methylphenidate but no difference between children with ADHD under placebo and typically developing children. © The Author(s) 2014.

Continuous direct compression as manufacturing platform for sustained release tablets.

PubMed

Van Snick, B; Holman, J; Cunningham, C; Kumar, A; Vercruysse, J; De Beer, T; Remon, J P; Vervaet, C

2017-03-15

This study presents a framework for process and product development on a continuous direct compression manufacturing platform. A challenging sustained release formulation with high content of a poorly flowing low density drug was selected. Two HPMC grades were evaluated as matrix former: standard Methocel CR and directly compressible Methocel DC2. The feeding behavior of each formulation component was investigated by deriving feed factor profiles. The maximum feed factor was used to estimate the drive command and depended strongly upon the density of the material. Furthermore, the shape of the feed factor profile allowed definition of a customized refill regime for each material. Inline NIRs was used to estimate the residence time distribution (RTD) in the mixer and monitor blend uniformity. Tablet content and weight variability were determined as additional measures of mixing performance. For Methocel CR, the best axial mixing (i.e. feeder fluctuation dampening) was achieved when an impeller with high number of radial mixing blades operated at low speed. However, the variability in tablet weight and content uniformity deteriorated under this condition. One can therefore conclude that balancing axial mixing with tablet quality is critical for Methocel CR. However, reformulating with the direct compressible Methocel DC2 as matrix former improved tablet quality vastly. Furthermore, both process and product were significantly more robust to changes in process and design variables. This observation underpins the importance of flowability during continuous blending and die-filling. At the compaction stage, blends with Methocel CR showed better tabletability driven by a higher compressibility as the smaller CR particles have a higher bonding area. However, tablets of similar strength were achieved using Methocel DC2 by targeting equal porosity. Compaction pressure impacted tablet properties and dissolution. Hence controlling thickness during continuous manufacturing of sustained release tablets was crucial to ensure reproducible dissolution. Copyright © 2017 Elsevier B.V. All rights reserved.

Exercise training in adults with repaired tetralogy of Fallot: A randomized controlled pilot study of continuous versus interval training.

PubMed

Novaković, Marko; Prokšelj, Katja; Rajkovič, Uroš; Vižintin Cuderman, Tjaša; Janša Trontelj, Katja; Fras, Zlatko; Jug, Borut

2018-03-15

Adults with repaired tetralogy of Fallot (ToF) have impaired exercise capacity, vascular and cardiac autonomic function, and quality of life (QoL). Specific effects of high-intensity interval or moderate continuous exercise training on these parameters in adults with repaired ToF remain unknown. Thirty adults with repaired ToF were randomized to either high-intensity interval, moderate intensity continuous training (36 sessions, 2-3 times a week) or usual care (no supervised exercise). Exercise capacity, flow-mediated vasodilation, pulse wave velocity, NT-proBNP and fibrinogen levels, heart rate variability and recovery, and QoL (SF-36 questionnaire) were determined at baseline and after the intervention period. Twenty-seven patients (mean age 39±9years, 63% females, 9 from each group) completed this pilot study. Both training groups improved in at least some parameters of cardiovascular health compared to no exercise. Interval-but not continuous-training improved VO2peak (21.2 to 22.9ml/kg/min, p=0.004), flow-mediated vasodilation (8.4 to 12.9%, p=0.019), pulse wave velocity (5.4 to 4.8m/s, p=0.028), NT-proBNP (202 to 190ng/L, p=0.032) and fibrinogen levels (2.67 to 2.46g/L, p=0.018). Conversely, continuous-but not interval-training improved heart rate variability (low-frequency domain, 0.32 to 0.22, p=0.039), heart rate recovery after 2min post-exercise (40 to 47 beats, p=0.023) and mental domain of SF-36 (87 to 95, p=0.028). Both interval and continuous exercise training modalities were safe. Interval training seems more efficacious in improving exercise capacity, vascular function, NT-proBNP and fibrinogen levels, while continuous training seems more efficacious in improving cardiac autonomic function and QoL. (Clinicaltrials.gov, NCT02643810). Copyright © 2018 Elsevier Ireland Ltd. All rights reserved.

Study for Air Vehicles at High Speeds, Identifying the Potential Benefits to Transport Aircraft of a Continuously Variable Geometry Trailing-Edge Structure that can be Utilized for Aircraft Control, Trim, Load-Alleviation, and High Lift

DTIC Science & Technology

2011-08-01

Field Length is defined as the total distance from brake release to the point at which the aircraft clears a height of 35 ft. The clearance height is...height clearance. The AEFL comprises two parts, the ground roll from brake release to lift-off (GR) plus the distance from lift-off to 35 ft height

NASA/USRA advanced design program activity, 1991-1992

NASA Astrophysics Data System (ADS)

Dorrity, J. Lewis; Patel, Suneer

The School of Textile and Fiber Engineering continued to pursue design projects with the Mechanical Engineering School giving the students an outstanding opportunity to interact with students from another discipline. Four problems were defined which had aspects which would be reasonably assigned to an interdisciplinary team. The design problems are described. The projects included lunar preform manufacturing, dust control for Enabler, an industrial sewing machine variable speed controllor, Enabler operation station, and design for producing fiberglass fabric in a lunar environment.

NASA/USRA advanced design program activity, 1991-1992

NASA Technical Reports Server (NTRS)

Dorrity, J. Lewis; Patel, Suneer

1992-01-01

The School of Textile and Fiber Engineering continued to pursue design projects with the Mechanical Engineering School giving the students an outstanding opportunity to interact with students from another discipline. Four problems were defined which had aspects which would be reasonably assigned to an interdisciplinary team. The design problems are described. The projects included lunar preform manufacturing, dust control for Enabler, an industrial sewing machine variable speed controllor, Enabler operation station, and design for producing fiberglass fabric in a lunar environment.

Augmented Computer Mouse Would Measure Applied Force

NASA Technical Reports Server (NTRS)

Li, Larry C. H.

1993-01-01

Proposed computer mouse measures force of contact applied by user. Adds another dimension to two-dimensional-position-measuring capability of conventional computer mouse; force measurement designated to represent any desired continuously variable function of time and position, such as control force, acceleration, velocity, or position along axis perpendicular to computer video display. Proposed mouse enhances sense of realism and intuition in interaction between operator and computer. Useful in such applications as three-dimensional computer graphics, computer games, and mathematical modeling of dynamics.

Demonstration of coherent-state discrimination using a displacement-controlled photon-number-resolving detector.

PubMed

Wittmann, Christoffer; Andersen, Ulrik L; Takeoka, Masahiro; Sych, Denis; Leuchs, Gerd

2010-03-12

We experimentally demonstrate a new measurement scheme for the discrimination of two coherent states. The measurement scheme is based on a displacement operation followed by a photon-number-resolving detector, and we show that it outperforms the standard homodyne detector which we, in addition, prove to be optimal within all Gaussian operations including conditional dynamics. We also show that the non-Gaussian detector is superior to the homodyne detector in a continuous variable quantum key distribution scheme.

Different operational meanings of continuous variable Gaussian entanglement criteria and Bell inequalities

NASA Astrophysics Data System (ADS)

Buono, D.; Nocerino, G.; Solimeno, S.; Porzio, A.

2014-07-01

Entanglement, one of the most intriguing aspects of quantum mechanics, marks itself into different features of quantum states. For this reason different criteria can be used for verifying entanglement. In this paper we review some of the entanglement criteria casted for continuous variable states and link them to peculiar aspects of the original debate on the famous Einstein-Podolsky-Rosen (EPR) paradox. We also provide a useful expression for valuating Bell-type non-locality on Gaussian states. We also present the experimental measurement of a particular realization of the Bell operator over continuous variable entangled states produced by a sub-threshold type-II optical parametric oscillators (OPOs).

Practical limitation for continuous-variable quantum cryptography using coherent States.

PubMed

Namiki, Ryo; Hirano, Takuya

2004-03-19

In this Letter, first, we investigate the security of a continuous-variable quantum cryptographic scheme with a postselection process against individual beam splitting attack. It is shown that the scheme can be secure in the presence of the transmission loss owing to the postselection. Second, we provide a loss limit for continuous-variable quantum cryptography using coherent states taking into account excess Gaussian noise on quadrature distribution. Since the excess noise is reduced by the loss mechanism, a realistic intercept-resend attack which makes a Gaussian mixture of coherent states gives a loss limit in the presence of any excess Gaussian noise.

Universal Quantum Computing with Measurement-Induced Continuous-Variable Gate Sequence in a Loop-Based Architecture.

PubMed

Takeda, Shuntaro; Furusawa, Akira

2017-09-22

We propose a scalable scheme for optical quantum computing using measurement-induced continuous-variable quantum gates in a loop-based architecture. Here, time-bin-encoded quantum information in a single spatial mode is deterministically processed in a nested loop by an electrically programmable gate sequence. This architecture can process any input state and an arbitrary number of modes with almost minimum resources, and offers a universal gate set for both qubits and continuous variables. Furthermore, quantum computing can be performed fault tolerantly by a known scheme for encoding a qubit in an infinite-dimensional Hilbert space of a single light mode.

Universal Quantum Computing with Measurement-Induced Continuous-Variable Gate Sequence in a Loop-Based Architecture

NASA Astrophysics Data System (ADS)

Takeda, Shuntaro; Furusawa, Akira

2017-09-01

We propose a scalable scheme for optical quantum computing using measurement-induced continuous-variable quantum gates in a loop-based architecture. Here, time-bin-encoded quantum information in a single spatial mode is deterministically processed in a nested loop by an electrically programmable gate sequence. This architecture can process any input state and an arbitrary number of modes with almost minimum resources, and offers a universal gate set for both qubits and continuous variables. Furthermore, quantum computing can be performed fault tolerantly by a known scheme for encoding a qubit in an infinite-dimensional Hilbert space of a single light mode.

Generation of 8.3 dB continuous variable quantum entanglement at a telecommunication wavelength of 1550 nm

NASA Astrophysics Data System (ADS)

Jinxia, Feng; Zhenju, Wan; Yuanji, Li; Kuanshou, Zhang

2018-01-01

Continuous variable quantum entanglement at a telecommunication wavelength of 1550 nm is experimentally generated using a single nondegenerate optical parametric amplifier based on a type-II periodically poled KTiOPO4 crystal. The triply resonant of the nondegenerate optical parametric amplifier is adjusted by tuning the crystal temperature and tilting the orientation of the crystal in the optical cavity. Einstein-Podolsky-Rosen-entangled beams with quantum correlations of 8.3 dB for both the amplitude and phase quadratures are experimentally generated. This system can be used for continuous variable fibre-based quantum communication.

Broadband continuous-variable entanglement source using a chirped poling nonlinear crystal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, J. S.; Sun, L.; Yu, X. Q.

2010-01-15

Aperiodically poled nonlinear crystal can be used as a broadband continuous-variable entanglement source and has strong stability under perturbations. We study the conversion dynamics of the sum-frequency generation and the quantum correlation of the two pump fields in a chirped-structure nonlinear crystal using the quantum stochastic method. The results show that there exists a frequency window for the pumps where two optical fields can perform efficient upconversion. The two pump fields are demonstrated to be entangled in the window and the chirped-structure crystal can be used as a continuous-variable entanglement source with a broad response bandwidth.

Variability of a "force signature" during windmill softball pitching and relationship between discrete force variables and pitch velocity.

PubMed

Nimphius, Sophia; McGuigan, Michael R; Suchomel, Timothy J; Newton, Robert U

2016-06-01

This study assessed reliability of discrete ground reaction force (GRF) variables over multiple pitching trials, investigated the relationships between discrete GRF variables and pitch velocity (PV) and assessed the variability of the "force signature" or continuous force-time curve during the pitching motion of windmill softball pitchers. Intraclass correlation coefficient (ICC) for all discrete variables was high (0.86-0.99) while the coefficient of variance (CV) was low (1.4-5.2%). Two discrete variables were significantly correlated to PV; second vertical peak force (r(5)=0.81, p=0.03) and time between peak forces (r(5)=-0.79; p=0.03). High ICCs and low CVs support the reliability of discrete GRF and PV variables over multiple trials and significant correlations indicate there is a relationship between the ability to produce force and the timing of this force production with PV. The mean of all pitchers' curve-average standard deviation of their continuous force-time curves demonstrated low variability (CV=4.4%) indicating a repeatable and identifiable "force signature" pattern during this motion. As such, the continuous force-time curve in addition to discrete GRF variables should be examined in future research as a potential method to monitor or explain changes in pitching performance. Copyright © 2016 Elsevier B.V. All rights reserved.

ON-Q infusion pump linked to increased hospital stay after total knee arthroplasty.

PubMed

O'Neil, Stephen; Danielson, Kristopher; Johnson, Kory; Matelic, Thomas

2018-06-01

The purpose of this study was to evaluate immediate postoperative pain control modalities after total knee arthroplasty at the author's specific institution and compare those modalities with patient satisfaction, rehabilitation status, and length of hospital stay. A retrospective chart review of 101 patients who underwent total knee arthroplasty from 2013 to 2016 was performed. Data was collected including the pain control modality, total pain medication consumption, physical therapy progress, length of hospital stay and Visual Analog Scores. Analysis was then performed using SAS proprietary software. Results were reported as statistically significant if p value was less than 0.05. Multiple variables proved to be statistically significant (p value <0.05) in this particular study. Patients who received Valium required more morphine equivalents on average and reported higher Visual Analog Scores (VAS). For those patients who received a lower extremity nerve block pre operatively, there was a decrease in morphine equivalents on postoperative day one and lower VAS. For those patients who received the continuous pain pump, ON-Q postoperatively, there was an average increase in length of hospital stay by one day and a decrease in ambulation on postoperative day one. Also, females required less overall pain medication on postoperative days two and three compared to their male counterparts. Finally, there was no statistically significant difference for those patients who received Lyrica (pregabalin) or NSAIDS for the parameters that were measured in this study. Postoperative pain control modalities after total knee arthroplasty are highly variable among physicians. This variability has allowed researchers to review each modality and compare and contrast the benefits with the potential adverse effects of these medications on total knee replacement outcomes. The data in this study suggests that the use of Valium is correlated with increased pain medication consumption and decreased patient satisfaction. Data from this study also reveals that patients who underwent preoperative nerve blocks experienced decreased pain on postoperative day one and greater patient satisfaction. The most notable contribution of this study was the discovery of the adverse effects of the continuous pain pump, ON-Q. Patients treated with this modality had decreased ambulation on postoperative day one and on average remained in the hospital one extra day, a variable that significantly increases the cost of a total knee arthroplasty for the hospital, the surgeon and the patient. Even though this data is significant, further studies should be performed to enhance our knowledge of postoperative pain control for these patients.

East Coast fever as a continued constraint to livestock improvement in Tanzania: a case study.

PubMed

Kambarage, D M

1995-08-01

An investigation was carried out into the cause of deaths in a recently established dairy farm with 211 animals. Clinical examination revealed that 14 out of 15 sick animals were depressed, pyrexic, anorexic and had variable degrees of respiratory distress and enlarged lymph nodes. These clinical signs were suggestive of East Coast fever (ECF). This was confirmed on positive demonstration of piroplasms and macroschizonts in blood and lymph node smears respectively, and on post-mortem examination. Parasites were also demonstrated in smears taken from 5 other animals which were pyrexic and had enlarged lymph nodes. Epidemiological investigation revealed that the occurrence of the disease was associated with contact with tick-infested pastures and unsatisfactory tick control due to improper dipping of the herd. The use of pasture by pastoral cattle which are rarely dipped also increased tick infestation. It is concluded that, unless effective disease control is applied ECF will continue to be a major killer disease of cattle in Tanzania.

Low-noise humidity controller for imaging water mediated processes in atomic force microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaponenko, I., E-mail: iaroslav.gaponenko@unige.ch; Gamperle, L.; Herberg, K.

2016-06-15

We demonstrate the construction of a novel low-noise continuous flow humidity controller and its integration with a commercial variable-temperature atomic force microscope fluid cell, allowing precise control of humidity and temperature at the sample during nanoscale measurements. Based on wet and dry gas mixing, the design allows a high mechanical stability to be achieved by means of an ultrasonic atomiser for the generation of water-saturated gas, improving upon previous bubbler-based architectures. Water content in the flow is measured both at the inflow and outflow of the fluid cell, enabling the monitoring of water condensation and icing, and allowing controlled variationmore » of the sample temperature independently of the humidity. To benchmark the performance of the controller, the results of detailed noise studies and time-based imaging of the formation of ice layers on highly oriented pyrolytic graphite are shown.« less

Effect of cinnamon on glucose control and lipid parameters.

PubMed

Baker, William L; Gutierrez-Williams, Gabriela; White, C Michael; Kluger, Jeffrey; Coleman, Craig I

2008-01-01

To perform a meta-analysis of randomized controlled trials of cinnamon to better characterize its impact on glucose and plasma lipids. A systematic literature search through July 2007 was conducted to identify randomized placebo-controlled trials of cinnamon that reported data on A1C, fasting blood glucose (FBG), or lipid parameters. The mean change in each study end point from baseline was treated as a continuous variable, and the weighted mean difference was calculated as the difference between the mean value in the treatment and control groups. A random-effects model was used. Five prospective randomized controlled trials (n = 282) were identified. Upon meta-analysis, the use of cinnamon did not significantly alter A1C, FBG, or lipid parameters. Subgroup and sensitivity analyses did not significantly change the results. Cinnamon does not appear to improve A1C, FBG, or lipid parameters in patients with type 1 or type 2 diabetes.

Mathematical model for adaptive control system of ASEA robot at Kennedy Space Center

NASA Technical Reports Server (NTRS)

Zia, Omar

1989-01-01

The dynamic properties and the mathematical model for the adaptive control of the robotic system presently under investigation at Robotic Application and Development Laboratory at Kennedy Space Center are discussed. NASA is currently investigating the use of robotic manipulators for mating and demating of fuel lines to the Space Shuttle Vehicle prior to launch. The Robotic system used as a testbed for this purpose is an ASEA IRB-90 industrial robot with adaptive control capabilities. The system was tested and it's performance with respect to stability was improved by using an analogue force controller. The objective of this research project is to determine the mathematical model of the system operating under force feedback control with varying dynamic internal perturbation in order to provide continuous stable operation under variable load conditions. A series of lumped parameter models are developed. The models include some effects of robot structural dynamics, sensor compliance, and workpiece dynamics.

Reconfigurable water-substrate based antennas with temperature control

NASA Astrophysics Data System (ADS)

Mobashsher, Ahmed Toaha; Abbosh, Amin

2017-06-01

We report an unexplored reconfigurable antenna development technique utilizing the concept of temperature variable electromagnetic properties of water. By applying this physical phenomena, we present highly efficient water-substrate based antennas whose operating frequencies can be continuously tuned. While taking the advantage of cost-effectiveness of liquid water, this dynamic tuning technique also alleviates the roadblocks to widespread use of reconfigurable liquid-based antennas for VHF and UHF bands. The dynamic reconfigurability is controlled merely via external thermal stimulus and does not require any physical change of the resonating structure. We demonstrate dynamic control of omnidirectional and directional antennas covering more than 14 and 12% fractional bandwidths accordingly, with more than 85% radiation efficiency. Our temperature control approach paves the intriguing way of exploring dynamic reconfigurability of water-based compact electromagnetic devices for non-static, in-motion and low-cost real-world applications.

Using the entire history in the analysis of nested case cohort samples.

PubMed

Rivera, C L; Lumley, T

2016-08-15

Countermatching designs can provide more efficient estimates than simple matching or case-cohort designs in certain situations such as when good surrogate variables for an exposure of interest are available. We extend pseudolikelihood estimation for the Cox model under countermatching designs to models where time-varying covariates are considered. We also implement pseudolikelihood with calibrated weights to improve efficiency in nested case-control designs in the presence of time-varying variables. A simulation study is carried out, which considers four different scenarios including a binary time-dependent variable, a continuous time-dependent variable, and the case including interactions in each. Simulation results show that pseudolikelihood with calibrated weights under countermatching offers large gains in efficiency if compared to case-cohort. Pseudolikelihood with calibrated weights yielded more efficient estimators than pseudolikelihood estimators. Additionally, estimators were more efficient under countermatching than under case-cohort for the situations considered. The methods are illustrated using the Colorado Plateau uranium miners cohort. Furthermore, we present a general method to generate survival times with time-varying covariates. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Simpson's Paradox, Lord's Paradox, and Suppression Effects are the same phenomenon – the reversal paradox

PubMed Central

Tu, Yu-Kang; Gunnell, David; Gilthorpe, Mark S

2008-01-01

This article discusses three statistical paradoxes that pervade epidemiological research: Simpson's paradox, Lord's paradox, and suppression. These paradoxes have important implications for the interpretation of evidence from observational studies. This article uses hypothetical scenarios to illustrate how the three paradoxes are different manifestations of one phenomenon – the reversal paradox – depending on whether the outcome and explanatory variables are categorical, continuous or a combination of both; this renders the issues and remedies for any one to be similar for all three. Although the three statistical paradoxes occur in different types of variables, they share the same characteristic: the association between two variables can be reversed, diminished, or enhanced when another variable is statistically controlled for. Understanding the concepts and theory behind these paradoxes provides insights into some controversial or contradictory research findings. These paradoxes show that prior knowledge and underlying causal theory play an important role in the statistical modelling of epidemiological data, where incorrect use of statistical models might produce consistent, replicable, yet erroneous results. PMID:18211676

From nanoelectronics to nano-spintronics.

PubMed

Wang, Kang L; Ovchinnikov, Igor; Xiu, Faxian; Khitun, Alex; Bao, Ming

2011-01-01

Today's electronics uses electron charge as a state variable for logic and computing operation, which is often represented as voltage or current. In this representation of state variable, carriers in electronic devices behave independently even to a few and single electron cases. As the scaling continues to reduce the physical feature size and to increase the functional throughput, two most outstanding limitations and major challenges, among others, are power dissipation and variability as identified by ITRS. This paper presents the expose, in that collective phenomena, e.g., spintronics using appropriate order parameters of magnetic moment as a state variable may be considered favorably for a new room-temperature information processing paradigm. A comparison between electronics and spintronics in terms of variability, quantum and thermal fluctuations will be presented. It shows that the benefits of the scalability to smaller sizes in the case of spintronics (nanomagnetics) include a much reduced variability problem as compared with today's electronics. In addition, another advantage of using nanomagnets is the possibility of constructing nonvolatile logics, which allow for immense power savings during system standby. However, most of devices with magnetic moment usually use current to drive the devices and consequently, power dissipation is a major issue. We will discuss approaches of using electric-field control of ferromagnetism in dilute magnetic semiconductor (DMS) and metallic ferromagnetic materials. With the DMSs, carrier-mediated transition from paramagnetic to ferromagnetic phases make possible to have devices work very much like field effect transistor, plus the non-volatility afforded by ferromagnetism. Then we will describe new possibilities of the use of electric field for metallic materials and devices: Spin wave devices with multiferroics materials. We will also further describe a potential new method of electric field control of metallic ferromagnetism via field effect of the Thomas Fermi surface layer.

Optimization of controlled release nanoparticle formulation of verapamil hydrochloride using artificial neural networks with genetic algorithm and response surface methodology.

PubMed

Li, Yongqiang; Abbaspour, Mohammadreza R; Grootendorst, Paul V; Rauth, Andrew M; Wu, Xiao Yu

2015-08-01

This study was performed to optimize the formulation of polymer-lipid hybrid nanoparticles (PLN) for the delivery of an ionic water-soluble drug, verapamil hydrochloride (VRP) and to investigate the roles of formulation factors. Modeling and optimization were conducted based on a spherical central composite design. Three formulation factors, i.e., weight ratio of drug to lipid (X1), and concentrations of Tween 80 (X2) and Pluronic F68 (X3), were chosen as independent variables. Drug loading efficiency (Y1) and mean particle size (Y2) of PLN were selected as dependent variables. The predictive performance of artificial neural networks (ANN) and the response surface methodology (RSM) were compared. As ANN was found to exhibit better recognition and generalization capability over RSM, multi-objective optimization of PLN was then conducted based upon the validated ANN models and continuous genetic algorithms (GA). The optimal PLN possess a high drug loading efficiency (92.4%, w/w) and a small mean particle size (∼100nm). The predicted response variables matched well with the observed results. The three formulation factors exhibited different effects on the properties of PLN. ANN in coordination with continuous GA represent an effective and efficient approach to optimize the PLN formulation of VRP with desired properties. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of neurofeedback on the short-term memory and continuous attention of patients with moderate traumatic brain injury: A preliminary randomized controlled clinical trial.

PubMed

Rostami, Reza; Salamati, Payman; Yarandi, Kourosh Karimi; Khoshnevisan, Alireza; Saadat, Soheil; Kamali, Zeynab Sadat; Ghiasi, Somaie; Zaryabi, Atefeh; Ghazi Mir Saeid, Seyed Shahab; Arjipour, Mehdi; Rezaee-Zavareh, Mohammad Saeid; Rahimi-Movaghar, Vafa

2017-10-01

There are some studies which showed neurofeedback therapy (NFT) can be effective in clients with traumatic brain injury (TBI) history. However, randomized controlled clinical trials are still needed for evaluation of this treatment as a standard option. This preliminary study was aimed to evaluate the effect of NFT on continuous attention (CA) and short-term memory (STM) of clients with moderate TBI using a randomized controlled clinical trial (RCT). In this preliminary RCT, seventeen eligible patients with moderate TBI were randomly allocated in two intervention and control groups. All the patients were evaluated for CA and STM using the visual continuous attention test and Wechsler memory scale-4th edition (WMS-IV) test, respectively, both at the time of inclusion to the project and four weeks later. The intervention group participated in 20 sessions of NFT through the first four weeks. Conversely, the control group participated in the same NF sessions from the fifth week to eighth week of the project. Eight subjects in the intervention group and five subjects in the control group completed the study. The mean and standard deviation of participants' age were (26.75 ± 15.16) years and (27.60 ± 8.17) years in experiment and control groups, respectively. All of the subjects were male. No significant improvement was observed in any variables of the visual continuous attention test and WMS-IV test between two groups (p ≥ 0.05). Based on our literature review, it seems that our study is the only study performed on the effect of NFT on TBI patients with control group. NFT has no effect on CA and STM in patients with moderate TBI. More RCTs with large sample sizes, more sessions of treatment, longer time of follow-up and different protocols are recommended. Copyright © 2017 Daping Hospital and the Research Institute of Surgery of the Third Military Medical University. Production and hosting by Elsevier B.V. All rights reserved.

Nasal Jet-CPAP (variable flow) versus Bubble-CPAP in preterm infants with respiratory distress: an open label, randomized controlled trial.

PubMed

Bhatti, A; Khan, J; Murki, S; Sundaram, V; Saini, S S; Kumar, P

2015-11-01

To compare the failure rates between Jet continuous positive airway pressure device (J-CPAP-variable flow) and Bubble continuous positive airway device (B-CPAP) in preterm infants with respiratory distress. Preterm newborns <34 weeks gestation with onset of respiratory distress within 6 h of life were randomized to receive J-CPAP (a variable flow device) or B-CPAP (continuous flow device). A standardized protocol was followed for titration, weaning and removal of CPAP. Pressure was monitored close to the nares in both the devices every 6 hours and settings were adjusted to provide desired CPAP. The primary outcome was CPAP failure rate within 72 h of life. Secondary outcomes were CPAP failure within 7 days of life, need for surfactant post-randomization, time to CPAP failure, duration of CPAP and complications of prematurity. An intention to treat analysis was done. One-hundred seventy neonates were randomized, 80 to J-CPAP and 90 to B-CPAP. CPAP failure rates within 72 h were similar in infants who received J-CPAP and in those who received B-CPAP (29 versus 21%; relative risks 1.4 (0.8 to 2.3), P=0.25). Mean (95% confidence intervals) time to CPAP failure was 59 h (54 to 64) in the Jet CPAP group in comparison with 65 h (62 to 68) in the Bubble CPAP group (log rank P=0.19). All other secondary outcomes were similar between the two groups. In preterm infants with respiratory distress starting within 6 h of life, CPAP failure rates were similar with Jet CPAP and Bubble CPAP.

How accurate are interpretations of curriculum-based measurement progress monitoring data? Visual analysis versus decision rules.

PubMed

Van Norman, Ethan R; Christ, Theodore J

2016-10-01

Curriculum based measurement of oral reading (CBM-R) is used to monitor the effects of academic interventions for individual students. Decisions to continue, modify, or terminate these interventions are made by interpreting time series CBM-R data. Such interpretation is founded upon visual analysis or the application of decision rules. The purpose of this study was to compare the accuracy of visual analysis and decision rules. Visual analysts interpreted 108 CBM-R progress monitoring graphs one of three ways: (a) without graphic aids, (b) with a goal line, or (c) with a goal line and a trend line. Graphs differed along three dimensions, including trend magnitude, variability of observations, and duration of data collection. Automated trend line and data point decision rules were also applied to each graph. Inferential analyses permitted the estimation of the probability of a correct decision (i.e., the student is improving - continue the intervention, or the student is not improving - discontinue the intervention) for each evaluation method as a function of trend magnitude, variability of observations, and duration of data collection. All evaluation methods performed better when students made adequate progress. Visual analysis and decision rules performed similarly when observations were less variable. Results suggest that educators should collect data for more than six weeks, take steps to control measurement error, and visually analyze graphs when data are variable. Implications for practice and research are discussed. Copyright © 2016 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.

Variability of eye movements when viewing dynamic natural scenes.

PubMed

Dorr, Michael; Martinetz, Thomas; Gegenfurtner, Karl R; Barth, Erhardt

2010-08-26

How similar are the eye movement patterns of different subjects when free viewing dynamic natural scenes? We collected a large database of eye movements from 54 subjects on 18 high-resolution videos of outdoor scenes and measured their variability using the Normalized Scanpath Saliency, which we extended to the temporal domain. Even though up to about 80% of subjects looked at the same image region in some video parts, variability usually was much greater. Eye movements on natural movies were then compared with eye movements in several control conditions. "Stop-motion" movies had almost identical semantic content as the original videos but lacked continuous motion. Hollywood action movie trailers were used to probe the upper limit of eye movement coherence that can be achieved by deliberate camera work, scene cuts, etc. In a "repetitive" condition, subjects viewed the same movies ten times each over the course of 2 days. Results show several systematic differences between conditions both for general eye movement parameters such as saccade amplitude and fixation duration and for eye movement variability. Most importantly, eye movements on static images are initially driven by stimulus onset effects and later, more so than on continuous videos, by subject-specific idiosyncrasies; eye movements on Hollywood movies are significantly more coherent than those on natural movies. We conclude that the stimuli types often used in laboratory experiments, static images and professionally cut material, are not very representative of natural viewing behavior. All stimuli and gaze data are publicly available at http://www.inb.uni-luebeck.de/tools-demos/gaze.

Macrosomia Predictors in Infants Born to Cuban Mothers with Gestational Diabetes.

PubMed

Cruz, Jeddú; Grandía, Raiden; Padilla, Liset; Rodríguez, Suilbert; Hernández García, Pilar; Lang Prieto, Jacinto; Márquez-Guillén, Antonio

2015-07-01

INTRODUCTION Fetal macrosomia is the most important complication in infants of women with diabetes, whether preconceptional or gestational. Its occurrence is related to certain maternal and fetal conditions and negatively affects maternal and perinatal outcomes. The definitive diagnosis is made at birth if a newborn weighs >4000 g. OBJECTIVE Identify which maternal and fetal conditions could be macrosomia predictors in infants born to Cuban mothers with gestational diabetes. METHODS A case-control study comprising 236 women with gestational diabetes who bore live infants (118 with macrosomia and 118 without) was conducted in the América Arias University Maternity Hospital, Havana, Cuba, during 2002-2012. The dependent variable was macrosomia (birth weight >4000 g). Independent maternal variables included body mass index at pregnancy onset, overweight or obesity at pregnancy onset, gestational age at diabetes diagnosis, pregnancy weight gain, glycemic control, triglycerides and cholesterol. Fetal variables examined included third-semester fetal abdominal circumference, estimated fetal weight at ≥28 weeks (absolute and percentilized by Campbell and Wilkin, and Usher and McLean curves). Chi square was used to compare continuous variables (proportions) and the student t test (X ± SD) for categorical variables, with significance threshold set at p <0.05. ORs and their 95% CIs were calculated. RESULTS Significant differences between cases and controls were found in most variables studied, with the exception of late gestational diabetes diagnosis, total fasting cholesterol and hypercholesterolemia. The highest OR for macrosomia were for maternal hypertriglyceridemia (OR 4.80, CI 2.34-9.84), third-trimester fetal abdominal circumference >75th percentile (OR 7.54, CI 4.04-14.06), and estimated fetal weight >90th percentile by Campbell and Wilkin curves (OR 4.75, CI 1.42-15.84) and by Usher and McLean curves (OR 8.81, CI 4.25-18.26). CONCLUSIONS Most variables assessed were predictors of macrosomia in infants of mothers with gestational diabetes. They should therefore be taken into account for future studies and for patient management. Wide confidence intervals indicate uncertainty about the magnitude of predictive power. KEYWORDS Fetal macrosomia, fetal diseases, gestational diabetes, risk factors, risk prediction, Cuba.

Impact of Targeted Preoperative Optimization on Clinical Outcome in Emergency Abdominal Surgeries: A Prospective Randomized Trial.

PubMed

Sethi, Ashish; Debbarma, Miltan; Narang, Neeraj; Saxena, Anudeep; Mahobia, Mamta; Tomar, Gaurav Singh

2018-01-01

Perforation peritonitis continues to be one of the most common surgical emergencies that need a surgical intervention most of the times. Anesthesiologists are invariably involved in managing such cases efficiently in perioperative period. The assessment and evaluation of Acute Physiology and Chronic Health Evaluation II (APACHE II) score at presentation and 24 h after goal-directed optimization, administration of empirical broad-spectrum antibiotics, and definitive source control postoperatively. Outcome assessment in terms of duration of hospital stay and mortality in with or without optimization was also measured. It is a prospective, randomized, double-blind controlled study in hospital setting. One hundred and one patients aged ≥18 years, of the American Society of Anesthesiologists physical Status I and II (E) with clinical diagnosis of perforation peritonitis posted for surgery were enrolled. Enrolled patients were randomly divided into two groups. Group A is optimized by goal-directed optimization protocol in the preoperative holding room by anesthesiology residents whereas in Group S, managed by surgery residents in the surgical wards without any fixed algorithm. The assessment of APACHE II score was done as a first step on admission and 24 h postoperatively. Duration of hospital stay and mortality in both the groups were also measured and compared. Categorical data are presented as frequency counts (percent) and compared using the Chi-square or Fisher's exact test. The statistical significance for categorical variables was determined by Chi-square analysis. For continuous variables, a two-sample t -test was applied. The mean APACHE II score on admission in case and control groups was comparable. Significant lowering of serial scores in case group was observed as compared to control group ( P = 0.02). There was a significant lowering of mean duration of hospital stay seen in case group (9.8 ± 1.7 days) as compared to control group ( P = 0.007). Furthermore, a significant decline in death rate was noted in case group as compared to control group ( P = 0.03). Goal-directed optimized patients with perforation peritonitis were discharged early as compared to control group with significantly lesser mortality as compared with randomly optimized patients in the perioperative period.

[Effect of Sijunzi Decoction and enteral nutrition on T-cell subsets and nutritional status in patients with gastric cancer after operation: a randomized controlled trial].

PubMed

Cai, Jun; Wang, Hua; Zhou, Sheng; Wu, Bin; Song, Hua-Rong; Xuan, Zheng-Rong

2008-01-01

To observe the effect of perioperative application of Sijunzi Decoction and enteral nutrition on T-cell subsets and nutritional status in patients with gastric cancer after operation. In this prospective, single-blinded, controlled clinical trial, fifty-nine patients with gastric cancer were randomly divided into three groups: control group (n=20) and two study groups (group A, n=21; group B, n=18). Sjunzi Decoction (100 ml) was administered via nasogastric tube to the patients in the study group B from the second postoperation day to the 9th postoperation day. Patients in the two study groups were given an isocaloric and isonitrogonous enteral diet, which was started on the second day after operation, and continued for eight days. Patients in the control group were given an isocaloric and isonitrogonous parenteral diet for 9 days. All variables of nutritional status such as serum albumin (ALB), prealbumin (PA), transferrin (TRF) and T-cell subsets were measured one day before operation, and one day and 10 days after operation. All the nutritional variables and the levels of CD3(+), CD4(+), CD4(+)/CD8(+) were decreased significantly after operation. Ten days after operation, T-cell subsets and nutritional variables in the two study groups were increased as compare with the control group. The levels of ALB, TRF and T-cell subsets in the study group B were increased significantly as compared with the study group A (P<0.05). Enteral nutrition assisted with Sijunzi Decoction can positively improve and optimize cellular immune function and nutritional status in the patients with gastric cancer after operation.

Associated and mediating variables related to quality of life among service users with mental disorders.

PubMed

Fleury, Marie-Josée; Grenier, Guy; Bamvita, Jean-Marie

2018-02-01

This study aimed to identify variables associated with quality of life (QoL) and mediating variables among 338 service users with mental disorders in Quebec (Canada). Data were collected using nine standardized questionnaires and participant medical records. Quality of life was assessed with the Satisfaction with Life Domains Scale. Independent variables were organized into a six-block conceptual framework. Using structural equation modeling, associated and mediating variables related to QoL were identified. Lower seriousness of needs was the strongest variable associated with QoL, followed by recovery, greater service continuity, gender (male), adequacy of help received, not living alone, absence of substance use or mood disorders, and higher functional status, in that order. Recovery was the single mediating variable linking lower seriousness of needs, higher service continuity, and reduced alcohol use with QoL. Findings suggest that greater service continuity creates favorable conditions for recovery, reducing seriousness of needs and increasing QoL among service users. Lack of recovery-oriented services may affect QoL among alcohol users, as substance use disorders were associated directly and negatively with QoL. Decision makers and mental health professionals should promote service continuity, and closer collaboration between primary care and specialized services, while supporting recovery-oriented services that encourage service user involvement in their treatment and follow-up. Community-based organizations should aim to reduce the seriousness of needs particularly for female service users and those living alone.

Utilizing Satellite Precipitation Products to Understand the Link Between Climate Variability and Malaria

NASA Astrophysics Data System (ADS)

Maggioni, V.; Mousam, A.; Delamater, P. L.; Cash, B. A.; Quispe, A.

2015-12-01

Malaria is a public health threat to people globally leading to 198 million cases and 584,000 deaths annually. Outbreaks of vector borne diseases such as malaria can be significantly impacted by climate variables such as precipitation. For example, an increase in rainfall has the potential to create pools of water that can serve as breeding locations for mosquitos. Peru is a country that is currently controlling malaria, but has not been able to completely eliminate the disease. Despite the various initiatives in order to control malaria - including regional efforts to improve surveillance, early detection, prompt treatment, and vector management - malaria cases in Peru have risen between 2011 and 2014. The purpose of this study is to test the hypothesis that climate variability plays a fundamental role in malaria occurrence over a 12-year period (2003-2014) in Peru. When analyzing climate variability, it is important to obtain high-quality, high-resolution data for a time series long enough to draw conclusion about how climate variables have been and are changing. Remote sensing is a powerful tool for measuring and monitoring climate variables continuously in time and space. A widely used satellite-based precipitation product, the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA), available globally since 1998, was used to obtain 3-hourly data with a spatial resolution of 0.25° x 0.25°. The precipitation data was linked to weekly (2003-2014) malaria cases collected by health centers and available at a district level all over Peru to investigate the relationship between precipitation and the seasonal and annual variations in malaria incidence. Further studies will incorporate additional climate variables such as temperature, humidity, soil moisture, and surface pressure from remote sensing data products and climate models. Ultimately, this research will help us to understand if climate variability impacts malaria incidence rates and to determine which regions of the country are most affected.

Got Rhythm? Better Inhibitory Control Is Linked with More Consistent Drumming and Enhanced Neural Tracking of the Musical Beat in Adult Percussionists and Nonpercussionists.

PubMed

Slater, Jessica; Ashley, Richard; Tierney, Adam; Kraus, Nina

2018-01-01

Musical rhythm engages motor and reward circuitry that is important for cognitive control, and there is evidence for enhanced inhibitory control in musicians. We recently revealed an inhibitory control advantage in percussionists compared with vocalists, highlighting the potential importance of rhythmic expertise in mediating this advantage. Previous research has shown that better inhibitory control is associated with less variable performance in simple sensorimotor synchronization tasks; however, this relationship has not been examined through the lens of rhythmic expertise. We hypothesize that the development of rhythm skills strengthens inhibitory control in two ways: by fine-tuning motor networks through the precise coordination of movements "in time" and by activating reward-based mechanisms, such as predictive processing and conflict monitoring, which are involved in tracking temporal structure in music. Here, we assess adult percussionists and nonpercussionists on inhibitory control, selective attention, basic drumming skills (self-paced, paced, and continuation drumming), and cortical evoked responses to an auditory stimulus presented on versus off the beat of music. Consistent with our hypotheses, we find that better inhibitory control is correlated with more consistent drumming and enhanced neural tracking of the musical beat. Drumming variability and the neural index of beat alignment each contribute unique predictive power to a regression model, explaining 57% of variance in inhibitory control. These outcomes present the first evidence that enhanced inhibitory control in musicians may be mediated by rhythmic expertise and provide a foundation for future research investigating the potential for rhythm-based training to strengthen cognitive function.

Kicking the Camel: Adolescent Smoking Behaviors after Two Years.

ERIC Educational Resources Information Center

Shillington, Audrey M.; Clapp, John D.

2000-01-01

Public Health Model was used to examine relationships between smoking severity (never smokers, former smokers, continued smokers) and host and environmental variables. Results indicate former smokers are more like never smokers on most risk and protective variables. Final analyses indicated continued smokers are more likely to be Non-Black and…

GY SAMPLING THEORY AND GEOSTATISTICS: ALTERNATE MODELS OF VARIABILITY IN CONTINUOUS MEDIA

EPA Science Inventory

In the sampling theory developed by Pierre Gy, sample variability is modeled as the sum of a set of seven discrete error components. The variogram used in geostatisties provides an alternate model in which several of Gy's error components are combined in a continuous mode...

Multi-stage Continuous Culture Fermentation of Glucose-Xylose Mixtures to Fuel Ethanol using Genetically Engineered Saccharomyces cerevisiae 424A

EPA Science Inventory

Multi-stage continuous (chemostat) culture fermentation (MCCF) with variable fermentor volumes was carried out to study utilizing glucose and xylose for ethanol production by means of mixed sugar fermentation (MSF). Variable fermentor volumes were used to enable enhanced sugar u...

Decomposing Intra-Subject Variability in Children with Attention-Deficit/Hyperactivity Disorder

PubMed Central

Di Martino, Adriana; Ghaffari, Manely; Curchack, Jocelyn; Reiss, Philip; Hyde, Christopher; Vannucci, Marina; Petkova, Eva; Klein, Donald F.; Castellanos, F. Xavier

2009-01-01

Background Increased intra-subject response time standard deviations (RT-SD) discriminate children with Attention-Deficit/Hyperactivity Disorder (ADHD) from healthy controls. RT-SD is averaged over time, thus it does not provide information about the temporal structure of response time variability. We previously hypothesized that such increased variability may be related to slow spontaneous fluctuations in brain activity occurring with periods between 15s and 40s. Here, we investigated whether these slow response time fluctuations add unique differentiating information beyond the global increase in RT-SD. Methods We recorded RT at 3s intervals for 15 minutes during an Eriksen flanker task for 29 children with ADHD and 26 age-matched typically developing controls (TDC) (mean ages 12.5 ± 2.4 and 11.6 ± 2.5; 26 and 12 boys, respectively). The primary outcome was the magnitude of the spectral component in the frequency range between 0.027 and 0.073 Hz measured with continuous Morlet wavelet transform. Results The magnitude of the low frequency fluctuation was greater for children with ADHD compared to TDC (p=0.02, d= 0.69). After modeling ADHD diagnosis as a function of RT-SD, adding this specific frequency range significantly improved the model fit (p=0.03; odds ratio= 2.58). Conclusions Fluctuations in low frequency response time variability predict the diagnosis of ADHD beyond the effect associated with global differences in variability. Future studies will examine whether such spectrally specific fluctuations in behavioral responses are linked to intrinsic regional cerebral hemodynamic oscillations which occur at similar frequencies. PMID:18423424

Multiscale adaptive analysis of circadian rhythms and intradaily variability: Application to actigraphy time series in acute insomnia subjects

PubMed Central

Rivera, Ana Leonor; Toledo-Roy, Juan C.; Ellis, Jason; Angelova, Maia

2017-01-01

Circadian rhythms become less dominant and less regular with chronic-degenerative disease, such that to accurately assess these pathological conditions it is important to quantify not only periodic characteristics but also more irregular aspects of the corresponding time series. Novel data-adaptive techniques, such as singular spectrum analysis (SSA), allow for the decomposition of experimental time series, in a model-free way, into a trend, quasiperiodic components and noise fluctuations. We compared SSA with the traditional techniques of cosinor analysis and intradaily variability using 1-week continuous actigraphy data in young adults with acute insomnia and healthy age-matched controls. The findings suggest a small but significant delay in circadian components in the subjects with acute insomnia, i.e. a larger acrophase, and alterations in the day-to-day variability of acrophase and amplitude. The power of the ultradian components follows a fractal 1/f power law for controls, whereas for those with acute insomnia this power law breaks down because of an increased variability at the 90min time scale, reminiscent of Kleitman’s basic rest-activity (BRAC) cycles. This suggests that for healthy sleepers attention and activity can be sustained at whatever time scale required by circumstances, whereas for those with acute insomnia this capacity may be impaired and these individuals need to rest or switch activities in order to stay focused. Traditional methods of circadian rhythm analysis are unable to detect the more subtle effects of day-to-day variability and ultradian rhythm fragmentation at the specific 90min time scale. PMID:28753669

Optimality and stability of intentional and unintentional actions: I. Origins of drifts in performance.

PubMed

Parsa, Behnoosh; Terekhov, Alexander; Zatsiorsky, Vladimir M; Latash, Mark L

2017-02-01

We address the nature of unintentional changes in performance in two papers. This first paper tested a hypothesis that unintentional changes in performance variables during continuous tasks without visual feedback are due to two processes. First, there is a drift of the referent coordinate for the salient performance variable toward the actual coordinate of the effector. Second, there is a drift toward minimum of a cost function. We tested this hypothesis in four-finger isometric pressing tasks that required the accurate production of a combination of total moment and total force with natural and modified finger involvement. Subjects performed accurate force-moment production tasks under visual feedback, and then visual feedback was removed for some or all of the salient variables. Analytical inverse optimization was used to compute a cost function. Without visual feedback, both force and moment drifted slowly toward lower absolute magnitudes. Over 15 s, the force drop could reach 20% of its initial magnitude while moment drop could reach 30% of its initial magnitude. Individual finger forces could show drifts toward both higher and lower forces. The cost function estimated using the analytical inverse optimization reduced its value as a consequence of the drift. We interpret the results within the framework of hierarchical control with referent spatial coordinates for salient variables at each level of the hierarchy combined with synergic control of salient variables. The force drift is discussed as a natural relaxation process toward states with lower potential energy in the physical (physiological) system involved in the task.

Optimality and stability of intentional and unintentional actions: I. Origins of drifts in performance

PubMed Central

Parsa, Behnoosh; Terekhov, Alexander; Zatsiorsky, Vladimir M.; Latash, Mark L.

2016-01-01

We address the nature of unintentional changes in performance in two papers. This first paper tested a hypothesis that unintentional changes in performance variables during continuous tasks without visual feedback are due to two processes. First, there is a drift of the referent coordinate for the salient performance variable toward the actual coordinate of the effector. Second, there is a drift toward minimum of a cost function. We tested this hypothesis in four-finger isometric pressing tasks that required the accurate production of a combination of total moment and total force with natural and modified finger involvement. Subjects performed accurate force/moment production tasks under visual feedback, and then visual feedback was removed for some or all of the salient variables. Analytical inverse optimization was used to compute a cost function. Without visual feedback, both force and moment drifted slowly toward lower absolute magnitudes. Over 15 s, the force drop could reach 20% of its initial magnitude while moment drop could reach 30% of its initial magnitude. Individual finger forces could show drifts toward both higher and lower forces. The cost function estimated using the analytical inverse optimization reduced its value as a consequence of the drift. We interpret the results within the framework of hierarchical control with referent spatial coordinates for salient variables at each level of the hierarchy combined with synergic control of salient variables. The force drift is discussed as a natural relaxation process toward states with lower potential energy in the physical (physiological) system involved in the task. PMID:27785549

Optimal Synthesis of Compliant Mechanisms using Subdivision and Commercial FEA (DETC2004-57497)

NASA Technical Reports Server (NTRS)

Hull, Patrick V.; Canfield, Stephen

2004-01-01

The field of distributed-compliance mechanisms has seen significant work in developing suitable topology optimization tools for their design. These optimal design tools have grown out of the techniques of structural optimization. This paper will build on the previous work in topology optimization and compliant mechanism design by proposing an alternative design space parameterization through control points and adding another step to the process, that of subdivision. The control points allow a specific design to be represented as a solid model during the optimization process. The process of subdivision creates an additional number of control points that help smooth the surface (for example a C(sup 2) continuous surface depending on the method of subdivision chosen) creating a manufacturable design free of some traditional numerical instabilities. Note that these additional control points do not add to the number of design parameters. This alternative parameterization and description as a solid model effectively and completely separates the design variables from the analysis variables during the optimization procedure. The motivation behind this work is to create an automated design tool from task definition to functional prototype created on a CNC or rapid-prototype machine. This paper will describe the proposed compliant mechanism design process and will demonstrate the procedure on several examples common in the literature.

Subjective and psychological well-being of students of a University of the Third Age: Benefits of continuing education for psychological adjustment in the elderly

PubMed Central

Ordonez, Tiago Nascimento; Lima-Silva, Thaís Bento; Cachioni, Meire

2011-01-01

Objectives The present study sought to characterize the degree of general satisfaction with life and degree of satisfaction on four domains: health, physical capacity, mental capacity and social involvement, and to determine the characteristics of self-reports of individuals enrolled on the program in relation to their psychological well-being focusing on the dimensions: autonomy, personal growth, control, positive relationships with others, purpose, personal acceptance and generativity, and to analyse the effect of time studying on level of well-being. Method A total of 140 elderly students of a University for the Third Age took part in the study. The Global Satisfaction With Life Scale and the Self Development Scale (with six psychological well-being subscales) were applied. Continuous variables for the two groups were compared using the Mann-Whitney test. Spearman’s correlation coefficient was used to analyze the relationship among numeric variables. Internal consistency of the instrument scales was analysed by calculating Cronbach’s alpha coefficient. Results Results showed that students who had attended the University of the Third Age for six months or longer had a higher level of satisfaction with life and greater psychological adjustment compared with new entrants to the same institution. Conclusion The study results confirmed the positive effects of continuing education on the well-being of elderly and its contribution to successful aging. PMID:29213747

Maximum wind energy extraction strategies using power electronic converters

NASA Astrophysics Data System (ADS)

Wang, Quincy Qing

2003-10-01

This thesis focuses on maximum wind energy extraction strategies for achieving the highest energy output of variable speed wind turbine power generation systems. Power electronic converters and controls provide the basic platform to accomplish the research of this thesis in both hardware and software aspects. In order to send wind energy to a utility grid, a variable speed wind turbine requires a power electronic converter to convert a variable voltage variable frequency source into a fixed voltage fixed frequency supply. Generic single-phase and three-phase converter topologies, converter control methods for wind power generation, as well as the developed direct drive generator, are introduced in the thesis for establishing variable-speed wind energy conversion systems. Variable speed wind power generation system modeling and simulation are essential methods both for understanding the system behavior and for developing advanced system control strategies. Wind generation system components, including wind turbine, 1-phase IGBT inverter, 3-phase IGBT inverter, synchronous generator, and rectifier, are modeled in this thesis using MATLAB/SIMULINK. The simulation results have been verified by a commercial simulation software package, PSIM, and confirmed by field test results. Since the dynamic time constants for these individual models are much different, a creative approach has also been developed in this thesis to combine these models for entire wind power generation system simulation. An advanced maximum wind energy extraction strategy relies not only on proper system hardware design, but also on sophisticated software control algorithms. Based on literature review and computer simulation on wind turbine control algorithms, an intelligent maximum wind energy extraction control algorithm is proposed in this thesis. This algorithm has a unique on-line adaptation and optimization capability, which is able to achieve maximum wind energy conversion efficiency through continuously improving the performance of wind power generation systems. This algorithm is independent of wind power generation system characteristics, and does not need wind speed and turbine speed measurements. Therefore, it can be easily implemented into various wind energy generation systems with different turbine inertia and diverse system hardware environments. In addition to the detailed description of the proposed algorithm, computer simulation results are presented in the thesis to demonstrate the advantage of this algorithm. As a final confirmation of the algorithm feasibility, the algorithm has been implemented inside a single-phase IGBT inverter, and tested with a wind simulator system in research laboratory. Test results were found consistent with the simulation results. (Abstract shortened by UMI.)

Dietary Inflammatory Index and risk of esophageal squamous cell cancer in a case-control study from Iran

PubMed Central

Shivappa, Nitin; Hébert, James R.; Rashidkhani, Bahram

2015-01-01

Background Diet and inflammation have been suggested to be important risk factors for esophageal squamous cell carcinoma (ESCC). In this study, we examined the ability of the dietary inflammatory index (DII) to predict ESCC in a case-control study conducted in Iran. Methods This study included 47 ESCC cases and 96 controls hospitalized for acute non-neoplastic diseases. The DII was computed based on dietary intake assessed by a previously validated food frequency questionnaire. Logistic regression models were used to estimate odds ratios (ORs) adjusted for age, energy, sex, BMI, years of education, physical activity, smoking and gastro-esophageal reflux. Results Subjects with higher DII scores (i.e., with a more pro-inflammatory diet) had a higher risk of ESCC, with the DII being used as both a continuous variable (ORcontinuous 3.58, 95% confidence interval, CI, 1.76–7.26; one unit increase corresponding to ≈16% of its range in the current study) and a categorical variable (ORdii>1.20 vs ≤ 1.208.24, 95%CI 2.03–33.47). Conclusion These results indicate that a pro-inflammatory diet is associated with increased risk of ESCC. PMID:26400625

Optimising multi-product multi-chance-constraint inventory control system with stochastic period lengths and total discount under fuzzy purchasing price and holding costs

NASA Astrophysics Data System (ADS)

Allah Taleizadeh, Ata; Niaki, Seyed Taghi Akhavan; Aryanezhad, Mir-Bahador

2010-10-01

While the usual assumptions in multi-periodic inventory control problems are that the orders are placed at the beginning of each period (periodic review) or depending on the inventory level they can happen at any time (continuous review), in this article, we relax these assumptions and assume that the periods between two replenishments of the products are independent and identically distributed random variables. Furthermore, assuming that the purchasing price are triangular fuzzy variables, the quantities of the orders are of integer-type and that there are space and service level constraints, total discount are considered to purchase products and a combination of back-order and lost-sales are taken into account for the shortages. We show that the model of this problem is a fuzzy mixed-integer nonlinear programming type and in order to solve it, a hybrid meta-heuristic intelligent algorithm is proposed. At the end, a numerical example is given to demonstrate the applicability of the proposed methodology and to compare its performance with one of the existing algorithms in real world inventory control problems.

Family context and externalizing correlates of childhood animal cruelty in adjudicated delinquents.

PubMed

Walters, Glenn D; Noon, Alexandria

2015-05-01

The purpose of this study was to determine whether childhood animal cruelty is primarily a feature of family context or of externalizing behavior. Twenty measures of family context and proactive (fearlessness) and reactive (disinhibition) externalizing behavior were correlated with the retrospective accounts of childhood animal cruelty provided by 1,354 adjudicated delinquents. A cross-sectional analysis revealed that all 20 family context, proactive externalizing, and reactive externalizing variables correlated significantly with animal cruelty. Prospective analyses showed that when the animal cruelty variable was included in a regression equation with the 10 family context variables (parental arguing and fighting, parental drug use, parental hostility, and parental knowledge and monitoring of offspring behavior) or in a regression equation with the five reactive externalizing variables (interpersonal hostility, secondary psychopathy, weak impulse control, weak suppression of aggression, and short time horizon), it continued to predict future violent and income (property + drug) offending. The animal cruelty variable no longer predicted offending, however, when included in a regression equation with the five proactive externalizing variables (early onset behavioral problems, primary psychopathy, moral disengagement, positive outcome expectancies for crime, and lack of consideration for others). These findings suggest that while animal cruelty correlates with a wide range of family context and externalizing variables, it may serve as a marker of violent and nonviolent offending by virtue of its position on the proactive subdimension of the externalizing spectrum. © The Author(s) 2014.

Intermittent But Not Continuous Static Stretching Improves Subsequent Vertical Jump Performance In Flexibility-Trained Athletes.

PubMed

Bogdanis, Gregory C; Donti, Olyvia; Tsolakis, Charilaos; Smilios, Ilias; Bishop, David J

2017-02-23

This study examined changes in countermovement jump (CMJ) height after an intermittent or a continuous static stretching protocol of equal total duration. Sixteen male, elite-level gymnasts performed 90 s of intermittent (3 x 30 s with 30 s rest) or continuous stretching (90 s) of the quadriceps muscle. A single-leg stretching and jumping design was used, with the contra-lateral limb serving as a control. The same individuals performed both conditions with alternate legs in a randomized, counterbalanced order. One leg CMJ height was measured for the stretched and the control leg after warm-up, immediately after stretching, and at regular intervals for 10 min after stretching. Range of motion (ROM) of the hip and knee joints was measured before, after, and 10 min post-stretching. Compared to the control leg, intermittent stretching increased CMJ height by 8.1±2.0%, 4 min into recovery (+2.2±2.0 cm, 95%CI: 1.0-3.4 cm, p=0.001), while continuous stretching decreased CMJ height by 17.5±3.3% immediately after (-2.9±1.7 cm, 95%CI: -2.0 to -3.7 cm, p=0.001) and by 12.0±2.7% one min after stretching (-2.2±2.1 cm, 95%CI: -1.2 to -3.2 cm, p=0.001). The increases in hip (2.9 and 3.6, p=0.001. d=2.4) and knee joint ROM (5.1 and 6.1, p=0.001. d=0.85) after the intermittent and continuous stretching protocols were not different. The opposite effects of intermittent vs. continuous stretching on subsequent CMJ performance suggests that stretching mode is an important variable when examining the acute effects of static stretching on performance in flexibility-trained athletes.

Holonomic Quantum Control with Continuous Variable Systems.

PubMed

Albert, Victor V; Shu, Chi; Krastanov, Stefan; Shen, Chao; Liu, Ren-Bao; Yang, Zhen-Biao; Schoelkopf, Robert J; Mirrahimi, Mazyar; Devoret, Michel H; Jiang, Liang

2016-04-08

Universal computation of a quantum system consisting of superpositions of well-separated coherent states of multiple harmonic oscillators can be achieved by three families of adiabatic holonomic gates. The first gate consists of moving a coherent state around a closed path in phase space, resulting in a relative Berry phase between that state and the other states. The second gate consists of "colliding" two coherent states of the same oscillator, resulting in coherent population transfer between them. The third gate is an effective controlled-phase gate on coherent states of two different oscillators. Such gates should be realizable via reservoir engineering of systems that support tunable nonlinearities, such as trapped ions and circuit QED.

FNAS/summer faculty fellowship research continuation program. Task 6: Integrated model development for liquid fueled rocket propulsion systems. Task 9: Aspects of model-based rocket engine condition monitoring and control

NASA Technical Reports Server (NTRS)

Santi, L. Michael; Helmicki, Arthur J.

1993-01-01

The objective of Phase I of this research effort was to develop an advanced mathematical-empirical model of SSME steady-state performance. Task 6 of Phase I is to develop component specific modification strategy for baseline case influence coefficient matrices. This report describes the background of SSME performance characteristics and provides a description of the control variable basis of three different gains models. The procedure used to establish influence coefficients for each of these three models is also described. Gains model analysis results are compared to Rocketdyne's power balance model (PBM).

Continued follow-up study of 120 persons born after refusal of application for therapeutic abortion.

PubMed

Forssman, H; Thuwe, I

1981-08-01

An investigation material consisting of 120 persons who were born after refusal of an application for therapeutic abortion, with the same number of controls, has previously been followed up by the writers to the age of 21 years. This follow-up study has now been extended to completion of the 35th year. It is found that in social-psychiatric respects the index cases as a group are still somewhat worse situated than the control cases. However, the differences have to a certain extent levelled out and during the later part of the observation period no statistically significant differences can be demonstrated for any single variable.

An ABS control logic based on wheel force measurement

NASA Astrophysics Data System (ADS)

Capra, D.; Galvagno, E.; Ondrak, V.; van Leeuwen, B.; Vigliani, A.

2012-12-01

The paper presents an anti-lock braking system (ABS) control logic based on the measurement of the longitudinal forces at the hub bearings. The availability of force information allows to design a logic that does not rely on the estimation of the tyre-road friction coefficient, since it continuously tries to exploit the maximum longitudinal tyre force. The logic is designed by means of computer simulation and then tested on a specific hardware in the loop test bench: the experimental results confirm that measured wheel force can lead to a significant improvement of the ABS performances in terms of stopping distance also in the presence of road with variable friction coefficient.

Emotional Intelligence in Patients with Spinal Cord Injury (SCI)

PubMed Central

SABERI, Hooshang; GHAJARZADEH, Mahsa

2017-01-01

Background: Spinal Cord Injury (SCI) is a devastating situation. Spinal Cord Injury affects functional, psychological and socioeconomic aspects of patients’ lives. The ability to accomplish and explicate the one’s own and other’s feelings and emotions to spread over appropriate information for confirming thoughts and actions is defined as emotional intelligence (EI). The goal of this study was to evaluate depression and EI in SCI patients in comparison with healthy subjects. Methods: One-hundred-ten patients with SCI and 80 healthy subjects between Aug 2014 and Aug 2015 were enrolled. The study was conducted in Imam Hospital, Tehran, Iran. All participants were asked to fill valid and reliable Persian version Emotional Quotient inventory (EQ-i) and Beck Depression Inventory (BDI). All data were analyzed using SPSS. Data were presented as Mean±SD for continuous or frequencies for categorical variables. Continuous variables compared by means of independent sample t-test. P-values less than 0.05 were considered as significant. Results: Mean age of patients was 28.7 and mean age of controls was 30.2 yr. Spinal cord injury in 20 (18.3%) were at cervical level, in 83 (75.4%) were thoracic and in 7 (6.3%) were lumbar. Mean values of independence, stress tolerance, self-actualization, emotional Self-Awareness, reality testing, Impulse Control, flexibility, responsibility, and assertiveness were significantly different between cases and controls. Mean values of stress tolerance, optimism, self-regard, and responsibility were significantly different between three groups with different injury level. Most scales were not significantly different between male and female cases. Conclusion: Emotional intelligence should be considered in SCI cases as their physical and psychological health is affected by their illness. PMID:28560199

Emotional Intelligence in Patients with Spinal Cord Injury (SCI).

PubMed

Saberi, Hooshang; Ghajarzadeh, Mahsa

2017-05-01

Spinal Cord Injury (SCI) is a devastating situation. Spinal Cord Injury affects functional, psychological and socioeconomic aspects of patients' lives. The ability to accomplish and explicate the one's own and other's feelings and emotions to spread over appropriate information for confirming thoughts and actions is defined as emotional intelligence (EI). The goal of this study was to evaluate depression and EI in SCI patients in comparison with healthy subjects. One-hundred-ten patients with SCI and 80 healthy subjects between Aug 2014 and Aug 2015 were enrolled. The study was conducted in Imam Hospital, Tehran, Iran. All participants were asked to fill valid and reliable Persian version Emotional Quotient inventory (EQ-i) and Beck Depression Inventory (BDI). All data were analyzed using SPSS. Data were presented as Mean±SD for continuous or frequencies for categorical variables. Continuous variables compared by means of independent sample t -test. P -values less than 0.05 were considered as significant. Mean age of patients was 28.7 and mean age of controls was 30.2 yr. Spinal cord injury in 20 (18.3%) were at cervical level, in 83 (75.4%) were thoracic and in 7 (6.3%) were lumbar. Mean values of independence, stress tolerance, self-actualization, emotional Self-Awareness, reality testing, Impulse Control, flexibility, responsibility, and assertiveness were significantly different between cases and controls. Mean values of stress tolerance, optimism, self-regard, and responsibility were significantly different between three groups with different injury level. Most scales were not significantly different between male and female cases. Emotional intelligence should be considered in SCI cases as their physical and psychological health is affected by their illness.

Shallow soil moisture - ground thaw interactions and controls - Part 2: Influences of water and energy fluxes

NASA Astrophysics Data System (ADS)

Guan, X. J.; Spence, C.; Westbrook, C. J.

2010-01-01

The companion paper (Guan et al., 2010) demonstrated variable interactions and correlations between shallow soil moisture and ground thaw in soil filled areas along a wetness spectrum in a subarctic Canadian Precambrian Shield landscape. From wetter to drier, these included a wetland, peatland and soil filled valley. Herein, water and energy fluxes were examined for these same subarctic study sites to discern the key controlling processes on the found patterns. Results showed the key control in variable soil moisture and frost table interactions among the sites was the presence of surface water. At the peatland and wetland sites, accumulated water in depressions and flow paths maintained soil moisture for a longer duration than at the hummock tops. These wet areas were often locations of deepest thaw depth due to the transfer of latent heat accompanying lateral surface runoff. Although the peatland and wetland sites had large inundation extent, modified Péclet numbers indicated the relative influence of external and internal hydrological processes at each site were different. Continuous inflow from an upstream lake into the wetland site caused advective and conductive thermal energies to be of equal importance to conductive ground thaw. The absence of continuous surface flow at the peatland and valley sites led to dominance of conductive thermal energy over advective energy for ground thaw. The results suggest that the modified Péclet number could be a very useful parameter to differentiate landscape components in modeling frost table heterogeneity. The calculated water and energy fluxes, and the modified Péclet number provide quantitative explanations for the shallow soil moisture-ground thaw patterns by linking them with hydrological processes and hillslope storage capacity.

Shallow soil moisture - ground thaw interactions and controls - Part 2: Influences of water and energy fluxes

NASA Astrophysics Data System (ADS)

Guan, X. J.; Spence, C.; Westbrook, C. J.

2010-07-01

The companion paper (Guan et al., 2010) demonstrated variable interactions and correlations between shallow soil moisture and ground thaw in soil filled areas along a wetness spectrum in a subarctic Canadian Precambrian Shield landscape. From wetter to drier, these included a wetland, peatland and soil filled valley. Herein, water and energy fluxes were examined for these same subarctic study sites to discern the key controlling processes on the found patterns. Results showed the presence of surface water was the key control in variable soil moisture and frost table interactions among sites. At the peatland and wetland sites, accumulated water in depressions and flow paths maintained soil moisture for a longer duration than at the hummock tops. These wet areas were often locations of deepest thaw depth due to the transfer of latent heat accompanying lateral surface runoff. Although the peatland and wetland sites had large inundation extent, modified Péclet numbers indicated the relative influence of external and internal hydrological and energy processes at each site were different. Continuous inflow from an upstream lake into the wetland site caused advective and conductive thermal energies to be of equal importance to ground thaw. The absence of continuous surface flow at the peatland and valley sites led to dominance of conductive thermal energy over advective energy for ground thaw. The results suggest that the modified Péclet number could be a very useful parameter to differentiate landscape components in modeling frost table heterogeneity. The calculated water and energy fluxes, and the modified Péclet number provide quantitative explanations for the shallow soil moisture-ground thaw patterns by linking them with hydrological processes and hillslope storage capacity.

[Stress level assessment of the nursing staff in the Intensive Care Unit of a university hospital].

PubMed

Carrillo-García, C; Ríos-Rísquez, M I; Martínez-Hurtado, R; Noguera-Villaescusa, P

2016-01-01

The objective was to determine the work stress level among nursing staff in the Intensive Care Unit of a university hospital and to analyse its relationship with the various sociodemographic and working variables of the studied sample. A study was designed using a quantitative, descriptive and cross-sectional approach. The target population of the study was the nursing staff selected by non-random sampling. The instrument used was the Job Content Questionnaire. Data analysis was performed using SPSS 20. The mean, ranges and standard deviation for each of the variables were calculated. A bivariate analysis was also performed on the social and occupational variables of the sample. The participation rate was 80.90% (N=89). The mean of the Social support dimension was 3.13±0.397, for the Psychological demands at work dimension it was 3.10±0.384, with a mean of 2.96±0.436 being obtained for the Control over the work dimension. In the analysis of sociodemographic and work variables of the sample, only the professional category was significant, with nurses recording higher values in perception of job demands and control over their work compared to nursing assistants. In conclusion, there is a moderate perception of work stress in the analysed group of professionals. Among the sources of stress in the workplace was the low control in decision-making by practitioners, as well as the need to continually learn new things. On the other hand, the support received from colleagues is valued positively by the sample. Copyright © 2016 Elsevier España, S.L.U. y SEEIUC. All rights reserved.

Investigation of Spray Cooling Schemes for Dynamic Thermal Management

NASA Astrophysics Data System (ADS)

Yata, Vishnu Vardhan Reddy

This study aims to investigate variable flow and intermittent flow spray cooling characteristics for efficiency improvement in active two-phase thermal management systems. Variable flow spray cooling scheme requires control of pump input voltage (or speed), while intermittent flow spray cooling scheme requires control of solenoid valve duty cycle and frequency. Several testing scenarios representing dynamic heat load conditions are implemented to characterize the overall performance of variable flow and intermittent flow spray cooling cases in comparison with the reference, steady flow spray cooling case with constant flowrate, continuous spray cooling. Tests are conducted on a small-scale, closed loop spray cooling system featuring a pressure atomized spray nozzle. HFE-7100 dielectric liquid is selected as the working fluid. Two types of test samples are prepared on 10 mm x 10 mm x 2 mm copper substrates with matching size thick film resistors attached onto the opposite side, to generate heat and simulate high heat flux electronic devices. The test samples include: (i) plain, smooth surface, and (ii) microporous surface featuring 100 ?m thick copper-based coating prepared by dual stage electroplating technique. Experimental conditions involve HFE-7100 at atmospheric pressure and 30°C and 10°C subcooling. Steady flow spray cooling tests are conducted at flow rates of 2-5 ml/cm2.s, by controlling the heat flux in increasing steps, and recording the corresponding steady-state temperatures to obtain cooling curves in the form of surface superheat vs. heat flux. Variable flow and intermittent flow spray cooling tests are done at selected flowrate and subcooling conditions to investigate the effects of dynamic flow conditions on maintaining the target surface temperatures defined based on reference steady flow spray cooling performance.

Baseline OCT Measurements in the Idiopathic Intracranial Hypertension Treatment Trial, Part I: Quality Control, Comparisons, and Variability

PubMed Central

2014-01-01

Purpose. Optical coherence tomography (OCT) has been used to investigate papilledema in single-site, mostly retrospective studies. We investigated whether spectral-domain OCT (SD-OCT), which provides thickness and volume measurements of the optic nerve head and retina, could reliably demonstrate structural changes due to papilledema in a prospective multisite clinical trial setting. Methods. At entry, 126 subjects in the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) with mild visual field loss had optic disc and macular scans, using the Cirrus SD-OCT. Images were analyzed by using the proprietary commercial and custom 3D-segmentation algorithms to calculate retinal nerve fiber layer (RNFL), total retinal thickness (TRT), optic nerve head volume (ONHV), and retinal ganglion cell layer (GCL) thickness. We evaluated variability, with interocular comparison and correlation between results for both methods. Results. The average RNFL thickness > 95% of normal controls in 90% of eyes and the RNFL, TRT, ONH height, and ONHV showed strong (r > 0.8) correlations for interocular comparisons. Variability for repeated testing of OCT parameters was low for both methods and intraclass correlations > 0.9 except for the proprietary GCL thickness. The proprietary algorithm–derived RNFL, TRT, and GCL thickness measurements had failure rates of 10%, 16%, and 20% for all eyes respectively, which were uncommon with 3D-segmentation–derived measurements. Only 7% of eyes had GCL thinning that was less than fifth percentile of normal age-matched control eyes by both methods. Conclusions. Spectral-domain OCT provides reliable continuous variables and quantified assessment of structural alterations due to papilledema. (ClinicalTrials.gov number, NCT01003639.) PMID:25370510

Yield impact for wafer shape misregistration-based binning for overlay APC diagnostic enhancement

NASA Astrophysics Data System (ADS)

Jayez, David; Jock, Kevin; Zhou, Yue; Govindarajulu, Venugopal; Zhang, Zhen; Anis, Fatima; Tijiwa-Birk, Felipe; Agarwal, Shivam

2018-03-01

The importance of traditionally acceptable sources of variation has started to become more critical as semiconductor technologies continue to push into smaller technology nodes. New metrology techniques are needed to pursue the process uniformity requirements needed for controllable lithography. Process control for lithography has the advantage of being able to adjust for cross-wafer variability, but this requires that all processes are close in matching between process tools/chambers for each process. When this is not the case, the cumulative line variability creates identifiable groups of wafers1 . This cumulative shape based effect is described as impacting overlay measurements and alignment by creating misregistration of the overlay marks. It is necessary to understand what requirements might go into developing a high volume manufacturing approach which leverages this grouping methodology, the key inputs and outputs, and what can be extracted from such an approach. It will be shown that this line variability can be quantified into a loss of electrical yield primarily at the edge of the wafer and proposes a methodology for root cause identification and improvement. This paper will cover the concept of wafer shape based grouping as a diagnostic tool for overlay control and containment, the challenges in implementing this in a manufacturing setting, and the limitations of this approach. This will be accomplished by showing that there are identifiable wafer shape based signatures. These shape based wafer signatures will be shown to be correlated to overlay misregistration, primarily at the edge. It will also be shown that by adjusting for this wafer shape signal, improvements can be made to both overlay as well as electrical yield. These improvements show an increase in edge yield, and a reduction in yield variability.

Effect of an orientation group for patients with chronic heart failure: randomized controlled trial 1

PubMed Central

Arruda, Cristina Silva; Pereira, Juliana de Melo Vellozo; Figueiredo, Lyvia da Silva; Scofano, Bruna dos Santos; Flores, Paula Vanessa Peclat; Cavalcanti, Ana Carla Dantas

2018-01-01

ABSTRACT Objective: To evaluate the effect of the orientation group on therapeutic adherence and self-care among patients with chronic heart failure. Method: Randomized controlled trial with 27 patients with chronic heart failure. The intervention group received nursing consultations and participated in group meetings with the multi-professional team. The control group only received nursing consultations in a period of four months. Questionnaires validated for use in Brazil were applied in the beginning and in the end of the study to assess self-care outcomes and adherence to treatment. Categorical variables were expressed through frequency and percentage distributions and the continuous variables through mean and standard deviation. The comparison between the initial and final scores of the intervention and control groups was done through the Student’s t-test. Results: The mean adherence in the intervention group was 13.9 ± 3.6 before the study and 4.8 ± 2.3 after the study. In the control group it was 14.2 ± 3.4 before the study and 14.7 ± 3.5 after the study. The self-care confidence score was lower after the intervention (p=0.01). Conclusion: The orientation group does not improve adherence to treatment and self-care management and maintenance and it may reduce confidence in self-care. Registry REBEC RBR-7r9f2m. PMID:29319747

Effect of an orientation group for patients with chronic heart failure: randomized controlled trial.

PubMed

Arruda, Cristina Silva; Pereira, Juliana de Melo Vellozo; Figueiredo, Lyvia da Silva; Scofano, Bruna Dos Santos; Flores, Paula Vanessa Peclat; Cavalcanti, Ana Carla Dantas

2018-01-08

To evaluate the effect of the orientation group on therapeutic adherence and self-care among patients with chronic heart failure. Randomized controlled trial with 27 patients with chronic heart failure. The intervention group received nursing consultations and participated in group meetings with the multi-professional team. The control group only received nursing consultations in a period of four months. Questionnaires validated for use in Brazil were applied in the beginning and in the end of the study to assess self-care outcomes and adherence to treatment. Categorical variables were expressed through frequency and percentage distributions and the continuous variables through mean and standard deviation. The comparison between the initial and final scores of the intervention and control groups was done through the Student's t-test. The mean adherence in the intervention group was 13.9 ± 3.6 before the study and 4.8 ± 2.3 after the study. In the control group it was 14.2 ± 3.4 before the study and 14.7 ± 3.5 after the study. The self-care confidence score was lower after the intervention (p=0.01). The orientation group does not improve adherence to treatment and self-care management and maintenance and it may reduce confidence in self-care. Registry REBEC RBR-7r9f2m.

Glycemic control of diabetes patients under continuous rocket attacks.

PubMed

Soskolne, Varda; Dekel, Rachel; Vinker, Shlomo

2016-01-01

Evidence regarding the detrimental effects of exposure to stress on glycemic control among diabetes patients has mainly focused on personal life events or acute trauma. However, the effects of continuous exposure to extreme stress on type 2 diabetes patients have rarely been studied. The aim of the current study was to examine the association of continuous exposure to rocket attacks with glycemic control and with risk factors for diabetes complications among civilian type 2 diabetes patients. We focus on patients residing in the Western Negev in the south of Israel that has been subjected to rocket attacks fired from Gaza since the end of 2001. A two-arm retrospective cohort study of type 2 diabetes patients, aged 35-70 years, residing in a region with chronic exposure to rocket attacks (N = 1697) and in a non-exposed comparison region in Israel (N = 3000). Data were retrieved from the Health Maintenance Organization (HMO)'s database for four time periods representing exposure: chronic-2008; elevated-2009 (post'Cast Lead' operation); return to chronic-2010, 2011. Data included socio-demographic variables, HbA 1c , BMI, LDL cholesterol, blood pressure. General Linear Models (GLM) were used for analysis. For HbA 1c , the model yielded a significant main effect for time, a borderline significance main effect for region, and a significant time by region interaction: no differences in HbA 1c levels between the regions in 2008 and 2009, followed by significant differences between the regions in 2010 and 2011 when HbA 1c continued to increase in the exposed region but decreased in the comparison region. Regarding risk factors, a significant main effect for time for LDL cholesterol only, and significant main effects for region were found in all factors: BMI and LDL cholesterol were higher in the exposed than in the comparison region, but blood pressure values were lower. Continuous exposure to rocket attacks is associated with glycemic control and risk factors in a complex pattern. These preliminary findings require further studies of diverse types of civilian exposure to continuous extreme stress.

A Polychoric Instrumental Variable (PIV) Estimator for Structural Equation Models with Categorical Variables

ERIC Educational Resources Information Center

Bollen, Kenneth A.; Maydeu-Olivares, Albert

2007-01-01

This paper presents a new polychoric instrumental variable (PIV) estimator to use in structural equation models (SEMs) with categorical observed variables. The PIV estimator is a generalization of Bollen's (Psychometrika 61:109-121, 1996) 2SLS/IV estimator for continuous variables to categorical endogenous variables. We derive the PIV estimator…

Mediating the distal crime-drug relationship with proximal reactive criminal thinking.

PubMed

Walters, Glenn D

2016-02-01

This article describes the results of a study designed to test whether reactive criminal thinking (RCT) does a better job of mediating the crime → drug relationship than it does mediating the drug → crime relationship after the direct effects of crime on drug use/dependency and of drug use/dependency on crime have been rendered nonsignificant by control variables. All 1,170 male members of the Pathways to Desistance study (Mulvey, 2012) served as participants in the current investigation. As predicted, the total (unmediated) effects of crime on substance use/dependence and of substance use/dependence on crime were nonsignificant when key demographic and third variables were controlled, although the indirect (RCT-mediated) effect of crime on drug use was significant. Proactive criminal thinking (PCT), by comparison, failed to mediate either relationship. The RCT continued to mediate the crime → drug relationship and the PCT continued to not mediate either relationship when more specific forms of offending (aggressive, income) and substance use/dependence (drug use, substance-use dependency symptoms) were analyzed. This offers preliminary support for the notion that even when the total crime-drug effect is nonsignificant the indirect path from crime to reactive criminal thinking to drugs can still be significant. Based on these results, it is concluded that mediation by proximal reactive criminal thinking is a mechanism by which distal measures of crime and drug use/dependence are connected. (c) 2016 APA, all rights reserved).

Suspended sediment and sediment-associated contaminants in San Francisco Bay

USGS Publications Warehouse

Schoellhamer, D.H.; Mumley, T.E.; Leatherbarrow, J.E.

2007-01-01

Water-quality managers desire information on the temporal and spatial variability of contaminant concentrations and the magnitudes of watershed and bed-sediment loads in San Francisco Bay. To help provide this information, the Regional Monitoring Program for Trace Substances in the San Francisco Estuary (RMP) takes advantage of the association of many contaminants with sediment particles by continuously measuring suspended-sediment concentration (SSC), which is an accurate, less costly, and more easily measured surrogate for several trace metals and organic contaminants. Continuous time series of SSC are collected at several sites in the Bay. Although semidiurnal and diurnal tidal fluctuations are present, most of the variability of SSC occurs at fortnightly, monthly, and semiannual tidal time scales. A seasonal cycle of sediment inflow, wind-wave resuspension, and winnowing of fine sediment also is observed. SSC and, thus, sediment-associated contaminants tend to be greater in shallower water, at the landward ends of the Bay, and in several localized estuarine turbidity maxima. Although understanding of sediment transport has improved in the first 10 years of the RMP, determining a simple mass budget of sediment or associated contaminants is confounded by uncertainties regarding sediment flux at boundaries, change in bed-sediment storage, and appropriate modeling techniques. Nevertheless, management of sediment-associated contaminants has improved greatly. Better understanding of sediment and sediment-associated contaminants in the Bay is of great interest to evaluate the value of control actions taken and the need for additional controls. ?? 2007 Elsevier Inc. All rights reserved.

Suspended sediment and sediment-associated contaminants in San Francisco Bay.

PubMed

Schoellhamer, David H; Mumley, Thomas E; Leatherbarrow, Jon E

2007-09-01

Water-quality managers desire information on the temporal and spatial variability of contaminant concentrations and the magnitudes of watershed and bed-sediment loads in San Francisco Bay. To help provide this information, the Regional Monitoring Program for Trace Substances in the San Francisco Estuary (RMP) takes advantage of the association of many contaminants with sediment particles by continuously measuring suspended-sediment concentration (SSC), which is an accurate, less costly, and more easily measured surrogate for several trace metals and organic contaminants. Continuous time series of SSC are collected at several sites in the Bay. Although semidiurnal and diurnal tidal fluctuations are present, most of the variability of SSC occurs at fortnightly, monthly, and semiannual tidal time scales. A seasonal cycle of sediment inflow, wind-wave resuspension, and winnowing of fine sediment also is observed. SSC and, thus, sediment-associated contaminants tend to be greater in shallower water, at the landward ends of the Bay, and in several localized estuarine turbidity maxima. Although understanding of sediment transport has improved in the first 10 years of the RMP, determining a simple mass budget of sediment or associated contaminants is confounded by uncertainties regarding sediment flux at boundaries, change in bed-sediment storage, and appropriate modeling techniques. Nevertheless, management of sediment-associated contaminants has improved greatly. Better understanding of sediment and sediment-associated contaminants in the Bay is of great interest to evaluate the value of control actions taken and the need for additional controls.

Interventions with children and parents to improve physical activity and body mass index: a meta-analysis.

PubMed

Dellert, Jane Cerruti; Johnson, Portia

2014-01-01

Examine the effect of interventions with parents and children on children's physical activity and body mass index (BMI). Computerized searches for intervention studies published between 1990 and 2011 used multiple ProQuest databases, including unpublished dissertations and theses to minimize publication bias. English-language, intervention-testing studies of children, parents, or families with outcomes of physical activity or BMI were retrieved from peer-reviewed journals, dissertations, and theses. Eliminated studies had no control or comparison group; had no continuous outcome variable; had no physical activity/exercise and/or BMI as outcomes; or had incomplete statistics necessary for meta-analysis (means, standard deviations, or confidence intervals). Twenty-one studies met inclusion criteria. Quality criteria were control group, objective outcome variable measure, clarity of variable definitions, and number and reason for subject withdrawal. Meta-analysis on the raw difference of means estimated mean weighted effect size (MWES) assessed dispersion of effects and computed a summary effect. MWES for interventions with parents and children on physical activity (Z = 2.92; confidence interval [CI] = .09 to .48; p = .002) and on BMI for interventions with children alone (Z = -2.10; CI = -.16 to -.01; p = .02) was significant. A significant effect on physical activity but not on BMI was found when interventions included both parents and their children.

Waist circumference, body mass index, and employment outcomes.

PubMed

Kinge, Jonas Minet

2017-07-01

Body mass index (BMI) is an imperfect measure of body fat. Recent studies provide evidence in favor of replacing BMI with waist circumference (WC). Hence, I investigated whether or not the association between fat mass and employment status vary by anthropometric measures. I used 15 rounds of the Health Survey for England (1998-2013), which has measures of employment status in addition to measured height, weight, and WC. WC and BMI were entered as continuous variables and obesity as binary variables defined using both WC and BMI. I used multivariate models controlling for a set of covariates. The association of WC with employment was of greater magnitude than the association between BMI and employment. I reran the analysis using conventional instrumental variables methods. The IV models showed significant impacts of obesity on employment; however, they were not more pronounced when WC was used to measure obesity, compared to BMI. This means that, in the IV models, the impact of fat mass on employment did not depend on the measure of fat mass.