An analysis of supersonic flows with low-Reynolds number compressible two-equation turbulence models using LU finite volume implicit numerical techniques

NASA Technical Reports Server (NTRS)

Lee, J.

1994-01-01

A generalized flow solver using an implicit Lower-upper (LU) diagonal decomposition based numerical technique has been coupled with three low-Reynolds number kappa-epsilon models for analysis of problems with engineering applications. The feasibility of using the LU technique to obtain efficient solutions to supersonic problems using the kappa-epsilon model has been demonstrated. The flow solver is then used to explore limitations and convergence characteristics of several popular two equation turbulence models. Several changes to the LU solver have been made to improve the efficiency of turbulent flow predictions. In general, the low-Reynolds number kappa-epsilon models are easier to implement than the models with wall-functions, but require much finer near-wall grid to accurately resolve the physics. The three kappa-epsilon models use different approaches to characterize the near wall regions of the flow. Therefore, the limitations imposed by the near wall characteristics have been carefully resolved. The convergence characteristics of a particular model using a given numerical technique are also an important, but most often overlooked, aspect of turbulence model predictions. It is found that some convergence characteristics could be sacrificed for more accurate near-wall prediction. However, even this gain in accuracy is not sufficient to model the effects of an external pressure gradient imposed by a shock-wave/ boundary-layer interaction. Additional work on turbulence models, especially for compressibility, is required since the solutions obtained with base line turbulence are in only reasonable agreement with the experimental data for the viscous interaction problems.

Solving the Swath Segment Selection Problem

NASA Technical Reports Server (NTRS)

Knight, Russell; Smith, Benjamin

2006-01-01

Several artificial-intelligence search techniques have been tested as means of solving the swath segment selection problem (SSSP) -- a real-world problem that is not only of interest in its own right, but is also useful as a test bed for search techniques in general. In simplest terms, the SSSP is the problem of scheduling the observation times of an airborne or spaceborne synthetic-aperture radar (SAR) system to effect the maximum coverage of a specified area (denoted the target), given a schedule of downlinks (opportunities for radio transmission of SAR scan data to a ground station), given the limit on the quantity of SAR scan data that can be stored in an onboard memory between downlink opportunities, and given the limit on the achievable downlink data rate. The SSSP is NP complete (short for "nondeterministic polynomial time complete" -- characteristic of a class of intractable problems that can be solved only by use of computers capable of making guesses and then checking the guesses in polynomial time).

Confined One Dimensional Harmonic Oscillator as a Two-Mode System

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

Gueorguiev, V G; Rau, A P; Draayer, J P

2005-07-11

The one-dimensional harmonic oscillator in a box problem is possibly the simplest example of a two-mode system. This system has two exactly solvable limits, the harmonic oscillator and a particle in a (one-dimensional) box. Each of the two limits has a characteristic spectral structure describing the two different excitation modes of the system. Near each of these limits, one can use perturbation theory to achieve an accurate description of the eigenstates. Away from the exact limits, however, one has to carry out a matrix diagonalization because the basis-state mixing that occurs is typically too large to be reproduced in anymore » other way. An alternative to casting the problem in terms of one or the other basis set consists of using an ''oblique'' basis that uses both sets. Through a study of this alternative in this one-dimensional problem, we are able to illustrate practical solutions and infer the applicability of the concept for more complex systems, such as in the study of complex nuclei where oblique-basis calculations have been successful.« less

Activity limitation and participation restriction in adults seeking hearing aid fitting and rehabilitation.

PubMed

Helvik, Anne-Sofie; Jacobsen, Geir; Wennberg, Siri; Arnesen, Haakon; Ringdahl, Anders; Hallberg, Lillemor R-M

2006-03-15

We first aimed to describe demographic and audiological characteristics of adults referred to a university hospital for hearing aid (HA) fitting and rehabilitation. Our second aim was to employ an inventory that assesses life consequences of hearing impairment (HI) in terms of perceived activity limitation and participation restriction for the first time in a Norwegian adult outpatient population. A third aim was to study life consequences by audiological and demographic characteristics. During one year consecutive patients (n = 343) were requested to answer the Hearing Disability and Handicap Scale (HDHS) assessing activity limitation and participation restriction in relation to an audiological examination and medical consultation. The mean threshold of hearing (MTH) was ascertained by pure tone thresholds at 0.5 - 1 - 2 - 4 kHz in the better ear. Activity limitation and participation restriction were both higher for HA experienced than HA naïve subjects ( p < 0.01). In a multivariable model, the explained adjusted variance of activity limitation (R2) was 43.4% with MTH, perceived duration, and severity of hearing problems as predictor variables. Correspondingly, the explained adjusted variance of participation restriction was 28.4% for a model with MTH, age, gender and perceived severity of hearing problems as predictors. As a standard supplement to audiometric tests, HDHS may be successfully applied as a clinical tool among similar hearing impaired outpatients in order to assess activity limitation and participation restriction as part of audiological rehabilitation.

Work Characteristics Associated with Physical Functioning in Women

PubMed Central

Palumbo, Aimee J.; De Roos, Anneclaire J.; Cannuscio, Carolyn; Robinson, Lucy; Mossey, Jana; Weitlauf, Julie; Garcia, Lorena; Wallace, Robert; Michael, Yvonne

2017-01-01

Women make up almost half of the labor force with older women becoming a growing segment of the population. Work characteristics influence physical functioning and women are at particular risk for physical limitations. However, little research has explored the effects of work characteristics on women’s physical functioning. U.S. women between the ages of 50 and 79 were enrolled in the Women’s Health Initiative Observational Study between 1993 and 1998. Women provided job titles and years worked at their three longest-held jobs (n = 79,147). Jobs were linked to characteristics in the Occupational Information Network. Three categories of job characteristics related to substantive complexity, physical demand, and social collaboration emerged. The association between job characteristics and physical limitations in later life, measured using a SF-36 Physical Functioning score <25th percentile, was examined using modified Poisson regression. After controlling for confounding variables, high physical demand was positively associated with physical limitations (RR = 1.09 CI: 1.06–1.12) and substantively complex work was negatively associated (RR = 0.94, CI: 0.91–0.96). Jobs requiring complex problem solving, active learning, and critical thinking were associated with better physical functioning. Employers should explore opportunities to reduce strain from physically demanding jobs and incorporate substantively complex tasks into women’s work to improve long-term health. PMID:28420131

Differentiating early-onset persistent versus childhood-limited conduct problem youth.

PubMed

Barker, Edward D; Maughan, Barbara

2009-08-01

Among young children who demonstrate high levels of conduct problems, less than 50% will continue to exhibit these problems into adolescence. Such developmental heterogeneity presents a serious challenge for intervention and diagnostic screening in early childhood. The purpose of the present study was to inform diagnostic screening and preventive intervention efforts by identifying youths whose conduct problems persist. The authors examined 1) the extent to which early-onset persistent versus childhood-limited trajectories can be identified from repeated assessments of childhood and early-adolescent conduct problems and 2) how prenatal and early postnatal risks differentiate these two groups. To identify heterogeneity in early-onset conduct problems, the authors used data from a large longitudinal population-based cohort of children followed from the prenatal period to age 13. Predictive risk factors examined were prenatal and postnatal measures of maternal distress (anxiety, depression), emotional and practical support, and family and child characteristics (from birth to 4 years of age). Findings revealed a distinction between early-onset persistent versus childhood-limited conduct problems in youths. Robust predictors of the early-onset persistent trajectory were maternal anxiety during pregnancy (32 weeks gestation), partner cruelty to the mother (from age 0 to 4 years), harsh parenting, and higher levels of child undercontrolled temperament. Sex differences in these risks were not identified. Interventions aiming to reduce childhood conduct problems should address prenatal risks in mothers and early postnatal risks in both mothers and their young children.

Suns-VOC characteristics of high performance kesterite solar cells

NASA Astrophysics Data System (ADS)

Gunawan, Oki; Gokmen, Tayfun; Mitzi, David B.

2014-08-01

Low open circuit voltage (VOC) has been recognized as the number one problem in the current generation of Cu2ZnSn(Se,S)4 (CZTSSe) solar cells. We report high light intensity and low temperature Suns-VOC measurement in high performance CZTSSe devices. The Suns-VOC curves exhibit bending at high light intensity, which points to several prospective VOC limiting mechanisms that could impact the VOC, even at 1 sun for lower performing samples. These VOC limiting mechanisms include low bulk conductivity (because of low hole density or low mobility), bulk or interface defects, including tail states, and a non-ohmic back contact for low carrier density CZTSSe. The non-ohmic back contact problem can be detected by Suns-VOC measurements with different monochromatic illuminations. These limiting factors may also contribute to an artificially lower JSC-VOC diode ideality factor.

Polymeric metallic electrodes for rechargeable battery applications

NASA Technical Reports Server (NTRS)

Somoano, R.

1982-01-01

A review is presented on the status of plastic metal electrodes, emphasizing the use of polyacetylene as a prototype polymeric material. The electrochemical characteristics of polyacetylene are examined; and the potential use of this material, as well as other types of plastic metal electrodes, in batteries is evaluated. Several problem areas which must be solved before polyacetylene can be widely used in battery applications are discussed, including the problem of electrolyte stability, the problem that the depth of discharge and the energy density is limited by the metal-semiconductor transition, and also the poor electrochemical performance of impure material.

Testing Alternative Explanations for the Associations between Parenting and Adolescent Suicidal Problems

ERIC Educational Resources Information Center

Boeninger, Daria K.; Masyn, Katherine E.; Conger, Rand D.

2013-01-01

Although studies have established associations between parenting characteristics and adolescent suicidality, the strength of the evidence for these links remains unclear, largely because of methodological limitations, including lack of accounting for possible child effects on parenting. This study addresses these issues by using autoregressive…

A methodology for the assessment of manned flight simulator fidelity

NASA Technical Reports Server (NTRS)

Hess, Ronald A.; Malsbury, Terry N.

1989-01-01

A relatively simple analytical methodology for assessing the fidelity of manned flight simulators for specific vehicles and tasks is offered. The methodology is based upon an application of a structural model of the human pilot, including motion cue effects. In particular, predicted pilot/vehicle dynamic characteristics are obtained with and without simulator limitations. A procedure for selecting model parameters can be implemented, given a probable pilot control strategy. In analyzing a pair of piloting tasks for which flight and simulation data are available, the methodology correctly predicted the existence of simulator fidelity problems. The methodology permitted the analytical evaluation of a change in simulator characteristics and indicated that a major source of the fidelity problems was a visual time delay in the simulation.

A Planning Approach of Engineering Characteristics Based on QFD-TRIZ Integrated

NASA Astrophysics Data System (ADS)

Liu, Shang; Shi, Dongyan; Zhang, Ying

Traditional QFD planning method compromises contradictions between engineering characteristics to achieve higher customer satisfaction. However, this compromise trade-off can not eliminate the contradictions existing among the engineering characteristics which limited the overall customer satisfaction. QFD (Quality function deployment) integrated with TRIZ (the Russian acronym of the Theory of Inventive Problem Solving) becomes hot research recently for TRIZ can be used to solve contradictions between engineering characteristics which construct the roof of HOQ (House of quality). But, the traditional QFD planning approach is not suitable for QFD integrated with TRIZ for that TRIZ requires emphasizing the contradictions between engineering characteristics at problem definition stage instead of compromising trade-off. So, a new planning approach based on QFD / TRIZ integration is proposed in this paper, which based on the consideration of the correlation matrix of engineering characteristics and customer satisfaction on the basis of cost. The proposed approach suggests that TRIZ should be applied to solve contradictions at the first step, and the correlation matrix of engineering characteristics should be amended at the second step, and at next step IFR (ideal final result) must be validated, then planning execute. An example is used to illustrate the proposed approach. The application indicated that higher customer satisfaction can be met and the contradictions between the characteristic parameters are eliminated.

Drinking characteristics of drivers arrested for driving while intoxicated in two police jurisdictions.

PubMed

Fell, James C; Tippetts, Scott; Voas, Robert

2010-10-01

Are drivers arrested for driving while intoxicated (DWI) most likely to be the drinking drivers who are involved in fatal and serious injury crashes? This study determined the drinking characteristics of drivers arrested for DWI or driving under the influence (DUI) and the proportion classified as problem drinkers and hardcore drinking drivers in two police jurisdictions. In addition to determining the drinking characteristics of DWI arrestees, the results were compared to the drinking characteristics of intoxicated drivers killed in traffic crashes. Police officers gathered data at the time of arrest from 1027 drivers apprehended for DWI or DUI in the two communities on their alcohol consumption, their drinking-and-driving frequency, their self-reported alcohol problems, their place of drinking and types of drinks before the arrest, and their perceptions of impaired-driving enforcement intensity. Data analyses indicated that 52 percent of the arrested DWI offenders were considered problem drinkers, 46 percent were repeat offenders, 57 percent were classified as hardcore drinking drivers, 51 percent were drinking at a bar or restaurant before their arrest, and 72 percent were drinking beer before their arrest. Compared to highly intoxicated (blood alcohol concentration [BAC] ≥.15) drivers killed in traffic crashes, the high-BAC arrestees were substantially more likely to be problem drinkers and to report drinking and driving more often. The limited resources available for combating impaired driving should not be solely allocated to problem drinkers, hardcore drinkers, or repeat offenders because, at most, they constitute only about half of the impaired-driving problem in the United States. General deterrent strategies have the best chance of impacting the total population of at-risk drinking drivers.

Some Operating Experience and Problems Encountered During Operation of a Free-jet Facility

NASA Technical Reports Server (NTRS)

Mcaulay, John E; Prince, William R

1957-01-01

During a free-jet investigation of a 28-inch ram-jet engine at a Mach number of 2.35, flow pulsation at the engine inlet were discovered which proved to have an effect on the engine performance and operational characteristics, particularly the engine rich blowout limits. This report discusses the finding of the flow pulsations, their elimination, and effect. Other facility characteristics, such as the establishment of flow simulation and the degree of subcritical operation of the diffuser, are also explained.

Transfer function modeling of damping mechanisms in viscoelastic plates

NASA Technical Reports Server (NTRS)

Slater, J. C.; Inman, D. J.

1991-01-01

This work formulates a method for the modeling of material damping characteristics in plates. The Sophie German equation of classical plate theory is modified to incorporate hysteresis effects represented by complex stiffness using the transfer function approach proposed by Golla and Hughes, (1985). However, this procedure is not limited to this representation. The governing characteristic equation is decoupled through separation of variables, yielding a solution similar to that of undamped classical plate theory, allowing solution of the steady state as well as the transient response problem.

Characteristics of psychiatric patients for whom financial considerations affect optimal treatment provision.

PubMed

West, Joyce C; Pingitore, David; Zarin, Deborah A

2002-12-01

This study assessed characteristics of psychiatric patients for whom financial considerations affected the provision of "optimal" treatment. Psychiatrists reported that for 33.8 percent of 1,228 patients from a national sample, financial considerations such as managed care limitations, the patient's personal finances, and limitations inherent in the public care system adversely affected the provision of optimal treatment. Patients were more likely to have their treatment adversely affected by financial considerations if they were more severely ill, had more than one behavioral health disorder or a psychosocial problem, or were receiving treatment under managed care arrangements. Patients for whom financial considerations affect the provision of optimal treatment represent a population for whom access to treatment may be particularly important.

Toward Strategic Independence: Policy Considerations for Enhancing School Effectiveness.

ERIC Educational Resources Information Center

Finn, Chester E., Jr.

The central problem in educational improvement at the state and local level is the tension between school-level autonomy and systemwide uniformity; educational change is limited by three special conditions: (1) inertial autonomy, (2) essential uniformity of public schools, and (3) the fact that effective schools have characteristics that cannot be…

Games that ''Work'': Using Computer Games to Teach Alcohol-Affected Children about Fire and Street Safety

ERIC Educational Resources Information Center

Coles, Claire D.; Strickland, Dorothy C.; Padgett, Lynne; Bellmoff, Lynnae

2007-01-01

Unintentional injuries are a leading cause of death and disability for children. Those with developmental disabilities, including children affected by prenatal alcohol exposure, are at highest risk for injuries. Although teaching safety skills is recommended to prevent injury, cognitive limitations and behavioral problems characteristic of…

A fluid model simulation of a simplified plasma limiter based on spectral-element time-domain method

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

Qian, Cheng; Ding, Dazhi, E-mail: dzding@njust.edu.cn; Fan, Zhenhong

2015-03-15

A simplified plasma limiter prototype is proposed and the fluid model coupled with Maxwell's equations is established to describe the operating mechanism of plasma limiter. A three-dimensional (3-D) simplified sandwich structure plasma limiter model is analyzed with the spectral-element time-domain (SETD) method. The field breakdown threshold of air and argon at different frequency is predicted and compared with the experimental data and there is a good agreement between them for gas microwave breakdown discharge problems. Numerical results demonstrate that the two-layer plasma limiter (plasma-slab-plasma) has better protective characteristics than a one-layer plasma limiter (slab-plasma-slab) with the same length of gasmore » chamber.« less

FDTD method for laser absorption in metals for large scale problems.

PubMed

Deng, Chun; Ki, Hyungson

2013-10-21

The FDTD method has been successfully used for many electromagnetic problems, but its application to laser material processing has been limited because even a several-millimeter domain requires a prohibitively large number of grids. In this article, we present a novel FDTD method for simulating large-scale laser beam absorption problems, especially for metals, by enlarging laser wavelength while maintaining the material's reflection characteristics. For validation purposes, the proposed method has been tested with in-house FDTD codes to simulate p-, s-, and circularly polarized 1.06 μm irradiation on Fe and Sn targets, and the simulation results are in good agreement with theoretical predictions.

An investigation of the psychological characteristics of stalkers: empathy, problem-solving, attachment and borderline personality features.

PubMed

Lewis, S F; Fremouw, W J; Del Ben, K; Farr, C

2001-01-01

This study examined the psychological characteristics of a sample of self-reported stalkers in comparison with a control group, on measures of empathy, problem-solving skills, attachment, and borderline personality features. Stalkers were identified by their endorsement of specific behavioral items, consistent with a widely adopted definition of stalking, denoting behaviors that: (a) are repeatedly directed toward an identified target; (b) are intrusive and unwanted; and (c) evoke fear in the victim. Stalkers scored significantly higher than controls on measures of insecure attachment and borderline personality features, suggesting that the stalking group demonstrates a general pattern of inadequate interpersonal attachment, has limited abilities to form and maintain appropriate relationships, is emotionally labile and unstable, and experiences ambivalence regarding their interpersonal relationships. Treatment implications are discussed herein.

Optimization of performance and emission characteristics of PPCCI engine fuelled with ethanol and diesel blends using grey-Taguchi method

NASA Astrophysics Data System (ADS)

Natarajan, S.; Pitchandi, K.; Mahalakshmi, N. V.

2018-02-01

The performance and emission characteristics of a PPCCI engine fuelled with ethanol and diesel blends were carried out on a single cylinder air cooled CI engine. In order to achieve the optimal process response with a limited number of experimental cycles, multi objective grey relational analysis had been applied for solving a multiple response optimization problem. Using grey relational grade and signal-to-noise ratio as a performance index, a combination of input parameters was prefigured so as to achieve optimum response characteristics. It was observed that 20% premixed ratio of blend was most suitable for use in a PPCCI engine without significantly affecting the engine performance and emissions characteristics.

Characteristic operator functions for quantum input-plant-output models and coherent control

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

Gough, John E.

We introduce the characteristic operator as the generalization of the usual concept of a transfer function of linear input-plant-output systems to arbitrary quantum nonlinear Markovian input-output models. This is intended as a tool in the characterization of quantum feedback control systems that fits in with the general theory of networks. The definition exploits the linearity of noise differentials in both the plant Heisenberg equations of motion and the differential form of the input-output relations. Mathematically, the characteristic operator is a matrix of dimension equal to the number of outputs times the number of inputs (which must coincide), but with entriesmore » that are operators of the plant system. In this sense, the characteristic operator retains details of the effective plant dynamical structure and is an essentially quantum object. We illustrate the relevance to model reduction and simplification definition by showing that the convergence of the characteristic operator in adiabatic elimination limit models requires the same conditions and assumptions appearing in the work on limit quantum stochastic differential theorems of Bouten and Silberfarb [Commun. Math. Phys. 283, 491-505 (2008)]. This approach also shows in a natural way that the limit coefficients of the quantum stochastic differential equations in adiabatic elimination problems arise algebraically as Schur complements and amounts to a model reduction where the fast degrees of freedom are decoupled from the slow ones and eliminated.« less

Aerodynamic studies of delta-wing shuttle orbiters. Part 1: Low speed

NASA Technical Reports Server (NTRS)

Freeman, D. C., Jr.; Ellison, J. C.

1972-01-01

Numerous wind tunnel tests conducted on the evolving delta-wing orbiters have generated a fairly large aerodynamic data base over the entire entry operation range of these vehicles. A limited assessment is made of some of the aerodynamics of the current HO type orbiters, and several specific problem areas selected from the broad data base are discussed. These include, from a subsonic viewpoint, discussions of trim drag effect; effects of the installation of main rocket engine nozzles, OMS and RCS packages, Reynolds number effects, lateral-directional stability characteristics, and landing characteristics.

A Longitudinal Examination of Risky Sexual Behaviors among Canadian and Italian Adolescents: Considering Individual, Parental, and Friend Characteristics

ERIC Educational Resources Information Center

Boislard P., Marie-Aude; Poulin, Francois; Kiesner, Jeff; Dishion, Thomas J.

2009-01-01

In this study, two longitudinal models of early adolescent risky sexual behaviors (RSB) were compared using a pooled sample of 267 Canadian and Italian adolescents (55% females; 53% Canadians) assessed yearly from grade 8 to 10. We focused on parenting practices (monitoring, control, limit setting), adolescent problem behaviors (antisocial…

The Limiting Velocity in Falling from a Great Height

NASA Technical Reports Server (NTRS)

Wilson, Edwin Bidwell

1919-01-01

The purpose of this report is to give a simple treatment of the problem of calculating the final or limiting velocity of an object falling in vertical motion under gravity in a resisting medium. The equations of motion are easily set up and integrated when the density of the medium is constant and the resistance varies as the square of the velocity. The results show that the fundamental characteristics of the vertical motion under gravity in a resisting medium is the approach to a terminal or limiting velocity, whether the initial downward velocity is less or greater than the limiting velocity. This method can be used to calculate the terminal velocity of a bomb trajectory.

Can callous-unemotional traits enhance the understanding, diagnosis, and treatment of serious conduct problems in children and adolescents? A comprehensive review.

PubMed

Frick, Paul J; Ray, James V; Thornton, Laura C; Kahn, Rachel E

2014-01-01

This article provides a comprehensive review of the research on the use of callous and unemotional (CU) traits for designating an important subgroup of children and adolescents with severe conduct problems. It focuses on the etiological significance of recognizing this subgroup of youths with severe conduct problems, its implications for diagnostic classification, and the treatment implications of this research. The review highlights limitations in existing research and provides directions for future research. The available research suggests that children and adolescents with severe conduct problems and elevated CU traits show distinct genetic, cognitive, emotional, biological, environmental, and personality characteristics that seem to implicate different etiological factors underlying their behavior problems relative to other youths with severe conduct problems. Recognizing these subgroups could be critical for guiding future research on the causes of severe conduct problems in children and adolescents. Further, children and adolescents with both severe conduct problems and elevated CU traits appear to be at risk for more severe and persistent antisocial outcomes, even controlling for the severity of their conduct problems, the age of onset of their conduct problems, and common comorbid problems, which supports the clinical importance of designating this group in diagnostic classification systems. Finally, although children and adolescents with both severe conduct problems and elevated CU traits tend to respond less positively to typical interventions provided in mental health and juvenile justice settings, they show positive responses to certain intensive interventions tailored to their unique emotional and cognitive characteristics. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

Ensemble-based data assimilation and optimal sensor placement for scalar source reconstruction

NASA Astrophysics Data System (ADS)

Mons, Vincent; Wang, Qi; Zaki, Tamer

2017-11-01

Reconstructing the characteristics of a scalar source from limited remote measurements in a turbulent flow is a problem of great interest for environmental monitoring, and is challenging due to several aspects. Firstly, the numerical estimation of the scalar dispersion in a turbulent flow requires significant computational resources. Secondly, in actual practice, only a limited number of observations are available, which generally makes the corresponding inverse problem ill-posed. Ensemble-based variational data assimilation techniques are adopted to solve the problem of scalar source localization in a turbulent channel flow at Reτ = 180 . This approach combines the components of variational data assimilation and ensemble Kalman filtering, and inherits the robustness from the former and the ease of implementation from the latter. An ensemble-based methodology for optimal sensor placement is also proposed in order to improve the condition of the inverse problem, which enhances the performances of the data assimilation scheme. This work has been partially funded by the Office of Naval Research (Grant N00014-16-1-2542) and by the National Science Foundation (Grant 1461870).

Operating characteristics of superconducting fault current limiter using 24kV vacuum interrupter driven by electromagnetic repulsion switch

NASA Astrophysics Data System (ADS)

Endo, M.; Hori, T.; Koyama, K.; Yamaguchi, I.; Arai, K.; Kaiho, K.; Yanabu, S.

2008-02-01

Using a high temperature superconductor, we constructed and tested a model Superconducting Fault Current Limiter (SFCL). SFCL which has a vacuum interrupter with electromagnetic repulsion mechanism. We set out to construct high voltage class SFCL. We produced the electromagnetic repulsion switch equipped with a 24kV vacuum interrupter(VI). There are problems that opening speed becomes late. Because the larger vacuum interrupter the heavier weight of its contact. For this reason, the current which flows in a superconductor may be unable to be interrupted within a half cycles of current. In order to solve this problem, it is necessary to change the design of the coil connected in parallel and to strengthen the electromagnetic repulsion force at the time of opening the vacuum interrupter. Then, the design of the coil was changed, and in order to examine whether the problem is solvable, the current limiting test was conducted. We examined current limiting test using 4 series and 2 parallel-connected YBCO thin films. We used 12-centimeter-long YBCO thin film. The parallel resistance (0.1Ω) is connected with each YBCO thin film. As a result, we succeed in interrupting the current of superconductor within a half cycle of it. Furthermore, series and parallel-connected YBCO thin film could limit without failure.

Science modelling in pre-calculus: how to make mathematics problems contextually meaningful

NASA Astrophysics Data System (ADS)

Sokolowski, Andrzej; Yalvac, Bugrahan; Loving, Cathleen

2011-04-01

'Use of mathematical representations to model and interpret physical phenomena and solve problems is one of the major teaching objectives in high school math curriculum' (National Council of Teachers of Mathematics (NCTM), Principles and Standards for School Mathematics, NCTM, Reston, VA, 2000). Commonly used pre-calculus textbooks provide a wide range of application problems. However, these problems focus students' attention on evaluating or solving pre-arranged formulas for given values. The role of scientific content is reduced to provide a background for these problems instead of being sources of data gathering for inducing mathematical tools. Students are neither required to construct mathematical models based on the contexts nor are they asked to validate or discuss the limitations of applied formulas. Using these contexts, the instructor may think that he/she is teaching problem solving, where in reality he/she is teaching algorithms of the mathematical operations (G. Kulm (ed.), New directions for mathematics assessment, in Assessing Higher Order Thinking in Mathematics, Erlbaum, Hillsdale, NJ, 1994, pp. 221-240). Without a thorough representation of the physical phenomena and the mathematical modelling processes undertaken, problem solving unintentionally appears as simple algorithmic operations. In this article, we deconstruct the representations of mathematics problems from selected pre-calculus textbooks and explicate their limitations. We argue that the structure and content of those problems limits students' coherent understanding of mathematical modelling, and this could result in weak student problem-solving skills. Simultaneously, we explore the ways to enhance representations of those mathematical problems, which we have characterized as lacking a meaningful physical context and limiting coherent student understanding. In light of our discussion, we recommend an alternative to strengthen the process of teaching mathematical modelling - utilization of computer-based science simulations. Although there are several exceptional computer-based science simulations designed for mathematics classes (see, e.g. Kinetic Book (http://www.kineticbooks.com/) or Gizmos (http://www.explorelearning.com/)), we concentrate mainly on the PhET Interactive Simulations developed at the University of Colorado at Boulder (http://phet.colorado.edu/) in generating our argument that computer simulations more accurately represent the contextual characteristics of scientific phenomena than their textual descriptions.

Organic coal-water fuel: Problems and advances (Review)

NASA Astrophysics Data System (ADS)

Glushkov, D. O.; Strizhak, P. A.; Chernetskii, M. Yu.

2016-10-01

The study results of ignition of organic coal-water fuel (OCWF) compositions were considered. The main problems associated with investigation of these processes were identified. Historical perspectives of the development of coal-water composite fuel technologies in Russia and worldwide are presented. The advantages of the OCWF use as a power-plant fuel in comparison with the common coal-water fuels (CWF) were emphasized. The factors (component ratio, grinding degree of solid (coal) component, limiting temperature of oxidizer, properties of liquid and solid components, procedure and time of suspension preparation, etc.) affecting inertia and stability of the ignition processes of suspensions based on the products of coaland oil processing (coals of various types and metamorphism degree, filter cakes, waste motor, transformer, and turbine oils, water-oil emulsions, fuel-oil, etc.) were analyzed. The promising directions for the development of modern notions on the OCWF ignition processes were determined. The main reasons limiting active application of the OCWF in power generation were identified. Characteristics of ignition and combustion of coal-water and organic coal-water slurry fuels were compared. The effect of water in the composite coal fuels on the energy characteristics of their ignition and combustion, as well as ecological features of these processes, were elucidated. The current problems associated with pulverization of composite coal fuels in power plants, as well as the effect of characteristics of the pulverization process on the combustion parameters of fuel, were considered. The problems hindering the development of models of ignition and combustion of OCWF were analyzed. It was established that the main one was the lack of reliable experimental data on the processes of heating, evaporation, ignition, and combustion of OCWF droplets. It was concluded that the use of high-speed video recording systems and low-inertia sensors of temperature and gas concentration could help in providing the lacking experimental information.

Sleep Spindle Characteristics in Children with Neurodevelopmental Disorders and Their Relation to Cognition

PubMed Central

Wise, Merrill S.

2016-01-01

Empirical evidence indicates that sleep spindles facilitate neuroplasticity and “off-line” processing during sleep, which supports learning, memory consolidation, and intellectual performance. Children with neurodevelopmental disorders (NDDs) exhibit characteristics that may increase both the risk for and vulnerability to abnormal spindle generation. Despite the high prevalence of sleep problems and cognitive deficits in children with NDD, only a few studies have examined the putative association between spindle characteristics and cognitive function. This paper reviews the literature regarding sleep spindle characteristics in children with NDD and their relation to cognition in light of what is known in typically developing children and based on the available evidence regarding children with NDD. We integrate available data, identify gaps in understanding, and recommend future research directions. Collectively, studies are limited by small sample sizes, heterogeneous populations with multiple comorbidities, and nonstandardized methods for collecting and analyzing findings. These limitations notwithstanding, the evidence suggests that future studies should examine associations between sleep spindle characteristics and cognitive function in children with and without NDD, and preliminary findings raise the intriguing question of whether enhancement or manipulation of sleep spindles could improve sleep-dependent memory and other aspects of cognitive function in this population. PMID:27478646

Rotorcraft Downwash Flow Field Study to Understand the Aerodynamics of Helicopter Brownout

NASA Technical Reports Server (NTRS)

Wadcock, Alan J.; Ewing, Lindsay A.; Solis, Eduardo; Potsdam, Mark; Rajagopalan, Ganesh

2008-01-01

Rotorcraft brownout is caused by the entrainment of dust and sand particles in helicopter downwash, resulting in reduced pilot visibility during low, slow flight and landing. Recently, brownout has become a high-priority problem for military operations because of the risk to both pilot and equipment. Mitigation of this problem has focused on flight controls and landing maneuvers, but current knowledge and experimental data describing the aerodynamic contribution to brownout are limited. This paper focuses on downwash characteristics of a UH-60 Blackhawk as they pertain to particle entrainment and brownout. Results of a full-scale tuft test are presented and used to validate a high-fidelity Navier-Stokes computational fluid dynamics (CFD) calculation. CFD analysis for an EH-101 Merlin helicopter is also presented, and its flow field characteristics are compared with those of the UH-60.

Comparison between the SCL-90-R and MMPI in TMD patients with psychological problems.

PubMed

Kim, M-J; Lim, M-J; Park, W-K; Kho, H-S

2012-03-01

The aim of the study was to investigate the relationships between the Symptom Checklist-90-Revision (SCL-90-R) and the Minnesota Multiphasic Personality Inventory (MMPI) in temporomandibular disorders (TMD) patients with psychological problems. Subjective symptoms, objective signs, and psychological characteristics of 36 TMD patients with psychological problems were analyzed. The symptom severity index (SSI) and craniomandibular index (CMI) were used to assess subjective symptoms and objective signs of patients with TMD, respectively. The SCL-90-R and MMPI were used for psychological evaluation. The SSI was not significantly correlated with the CMI in TMD patients with psychological problems, and these indices displayed significant correlations with the SCL-90-R and MMPI in several selected subscales. The results of SCL-90-R had a limited relationship with those of MMPI in these patients. Based on the MMPI diagnosis, the SCL-90-R somatization subscale showed moderate to high sensitivity and specificity, but the SCL-90-R depression subscale showed moderate to low sensitivity and specificity. Considering the limited relationship between the SCL-90-R and MMPI in TMD patients with psychological problems, more comprehensive psychological tests are recommended when clinicians suspect patients with TMD of having accompanying psychological problems. © 2011 John Wiley & Sons A/S.

A longitudinal comparative study of the physical and mental health problems of affected residents of the firework disaster Enschede, The Netherlands.

PubMed

Grievink, L; van der Velden, P G; Stellato, R K; Dusseldorp, A; Gersons, B P R; Kleber, R J; Lebret, E

2007-05-01

After the firework disaster in Enschede, The Netherlands, on 13 May 2000, a longitudinal health study was carried out. Study questions were: (1) did the health status change over this period; and (2) how is the health status 18 months after the disaster compared with controls? A longitudinal comparative study with two surveys at 3 weeks and 18 months after the disaster. A control group for the affected residents was included in the second survey. Respondents filled in a set of validated questionnaires measuring their physical and mental health problems. The prevalence of physical and emotional role limitations, severe sleeping problems, feelings of depression and anxiety, as well as intrusion and avoidance decreased from 3 weeks to 18 months after the disaster for the affected residents. Independent of background characteristics and other life events, residents had 1.5 to three times more health problems than the control group; for example, physical role limitations (odds ratio [OR]=1.5, 95% confidence interval [CI] 1.2-2.0) and anxiety (OR=3.1, 95% CI 2.4-4.2). Although health problems decreased compared with 3 weeks after the disaster, 18 months after the disaster, the affected residents had more health problems than the people from the control group.

System Engineering of Autonomous Space Vehicles

NASA Technical Reports Server (NTRS)

Watson, Michael D.; Johnson, Stephen B.; Trevino, Luis

2014-01-01

Human exploration of the solar system requires fully autonomous systems when travelling more than 5 light minutes from Earth. This autonomy is necessary to manage a large, complex spacecraft with limited crew members and skills available. The communication latency requires the vehicle to deal with events with only limited crew interaction in most cases. The engineering of these systems requires an extensive knowledge of the spacecraft systems, information theory, and autonomous algorithm characteristics. The characteristics of the spacecraft systems must be matched with the autonomous algorithm characteristics to reliably monitor and control the system. This presents a large system engineering problem. Recent work on product-focused, elegant system engineering will be applied to this application, looking at the full autonomy stack, the matching of autonomous systems to spacecraft systems, and the integration of different types of algorithms. Each of these areas will be outlined and a general approach defined for system engineering to provide the optimal solution to the given application context.

Estimation of finite mixtures using the empirical characteristic function

NASA Technical Reports Server (NTRS)

Anderson, C.; Boullion, T.

1985-01-01

A problem which occurs in analyzing LANDSAT scenes is the problem of separating the components of a finite mixture of several distinct probability distributions. A review of the literature indicates this is a problem which occurs in many disciplines, such as engineering, biology, physiology and economics. Many approaches to this problem have appeared in the literature; however, most are very restrictive in their assumptions or have met with only a limited degree of success when applied to realistic situations. A proceudre is investigated with combines the k-L procedure of (Feurverger and McDunnough, 1981) with the MAICE procedure of (Akaike, 1974). The feasibility of this approach is being investigated numerically via the development of a computer software package enabling a simulation study and comparison with other procedures.

Atypical Hallerman-Streif syndrome: a case report.

PubMed

Gopakumar, Manju; Hedge, Amitha M

2005-01-01

Hallerman Streif syndrome is a rare congenital disorder characterized by dyscephaly, dental anomalies, proportionate nazism, hypotrichosis, cutaneous atrophy limited to the head, bilateral congenital cataracts and bilateral microphthalmia. Despite the marked craniofacial characteristics and oral findings, a relative lack of reports in the dental literature has been noted. In this article, a case of a 8 year old boy with dental problems is described.

Factors influencing pharmacist performance: a review of the peer-reviewed literature.

PubMed

Schafheutle, Ellen Ingrid; Seston, Elizabeth Mary; Hassell, Karen

2011-10-01

To undertake a review of peer-reviewed literature to explore factors affecting pharmacists' performance. The following databases were searched: Medline, Embase, Scopus, ISI Web of Knowledge and PsychInfo. Inclusion criteria were: English language only, published between 1990 and 2010 and published in the United Kingdom (UK), United States of America (USA), Canada, Australia, New Zealand or Europe. The search strategy identified 37 items. The review found that there was some evidence to suggest that pharmacists with certain characteristics (e.g. being male, being of ethnic minority origin, working in community pharmacy and having trained overseas) were more likely to experience performance problems. Factors relating to workload and work environment were associated with performance problems, particularly in relation to errors. There was some limited evidence to suggest that experiencing problems with alcohol or drugs could negatively impact on pharmacists' performance. The findings suggest that pharmacist performance may be affected by multiple factors, including personal characteristics such as age, gender, ethnicity, place of primary qualification, factors associated with the workplace and mental and physical health problems. The evidence is not unequivocal and gaps in the literature exist, suggesting that pharmacist performance is an under-researched area. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Generalized closed form solutions for feasible dimension limit and pull-in characteristics of nanocantilever under the Influences of van der Waals and Casimir forces

NASA Astrophysics Data System (ADS)

Mukherjee, Banibrata; Sen, Siddhartha

2018-04-01

This paper presents generalized closed form expressions for determining the dimension limit for the basic design parameters as well as the pull-in characteristics of a nanocantilever beam under the influences of van der Waals and Casimir forces. The coupled nonlinear electromechanical problem of electrostatic nanocantilever is formulated in nondimensional form with Galerkin’s approximation considering the effects of these intermolecular forces and fringe field. The resulting integrals and higher order polynomials are solved numerically to derive the closed form expressions for maximum permissible detachment length, minimum feasible gap spacing and critical pull-in limit. The derived expressions are compared and validated as well with several reported literature showing reasonable agreement. The major advantages of the proposed closed form expressions are that, they do not contain any complex mathematical term or operation unlike in reported literature and thus they will serve as convenient tools for the NEMS community in successful design of various electrostatically actuated nanosystems.

Wind tunnel pressurization and recovery system

NASA Technical Reports Server (NTRS)

Pejack, Edwin R.; Meick, Joseph; Ahmad, Adnan; Lateh, Nordin; Sadeq, Omar

1988-01-01

The high density, low toxicity characteristics of refrigerant-12 (dichlorofluoromethane) make it an ideal gas for wind tunnel testing. Present limitations on R-12 emissions, set to slow the rate of ozone deterioration, pose a difficult problem in recovery and handling of large quantities of R-12. This preliminary design is a possible solution to the problem of R-12 handling in wind tunnel testing. The design incorporates cold temperature condensation with secondary purification of the R-12/air mixture by adsorption. Also discussed is the use of Freon-22 as a suitable refrigerant for the 12 foot wind tunnel.

Comparison of the quench and fault current limiting characteristics of the flux-coupling type SFCL with single and three-phase transformer

NASA Astrophysics Data System (ADS)

Jung, Byung Ik; Cho, Yong Sun; Park, Hyoung Min; Chung, Dong Chul; Choi, Hyo Sang

2013-01-01

The South Korean power grid has a network structure for the flexible operation of the system. The continuously increasing power demand necessitated the increase of power facilities, which decreased the impedance in the power system. As a result, the size of the fault current in the event of a system fault increased. As this increased fault current size is threatening the breaking capacity of the circuit breaker, the main protective device, a solution to this problem is needed. The superconducting fault current limiter (SFCL) has been designed to address this problem. SFCL supports the stable operation of the circuit breaker through its excellent fault-current-limiting operation [1-5]. In this paper, the quench and fault current limiting characteristics of the flux-coupling-type SFCL with one three-phase transformer were compared with those of the same SFCL type but with three single-phase transformers. In the case of the three-phase transformers, both the superconducting elements of the fault and sound phases were quenched, whereas in the case of the single-phase transformer, only that of the fault phase was quenched. For the fault current limiting rate, both cases showed similar rates for the single line-to-ground fault, but for the three-wire earth fault, the fault current limiting rate of the single-phase transformer was over 90% whereas that of the three-phase transformer was about 60%. It appears that when the three-phase transformer was used, the limiting rate decreased because the fluxes by the fault current of each phase were linked in one core. When the power loads of the superconducting elements were compared by fault type, the initial (half-cycle) load was great when the single-phase transformer was applied, whereas for the three-phase transformer, its power load was slightly lower at the initial stage but became greater after the half fault cycle.

Perform - A performance optimizing computer program for dynamic systems subject to transient loadings

NASA Technical Reports Server (NTRS)

Pilkey, W. D.; Wang, B. P.; Yoo, Y.; Clark, B.

1973-01-01

A description and applications of a computer capability for determining the ultimate optimal behavior of a dynamically loaded structural-mechanical system are presented. This capability provides characteristics of the theoretically best, or limiting, design concept according to response criteria dictated by design requirements. Equations of motion of the system in first or second order form include incompletely specified elements whose characteristics are determined in the optimization of one or more performance indices subject to the response criteria in the form of constraints. The system is subject to deterministic transient inputs, and the computer capability is designed to operate with a large linear programming on-the-shelf software package which performs the desired optimization. The report contains user-oriented program documentation in engineering, problem-oriented form. Applications cover a wide variety of dynamics problems including those associated with such diverse configurations as a missile-silo system, impacting freight cars, and an aircraft ride control system.

Resilience characteristics mitigate tendency for harmful alcohol and illicit drug use in adults with a history of childhood abuse: a cross-sectional study of 2024 inner-city men and women.

PubMed

Wingo, Aliza P; Ressler, Kerry J; Bradley, Bekh

2014-04-01

Resilience refers to abilities to cope adaptively with adversity or trauma. A common psychological sequella of childhood abuse or other traumatic experiences is substance use problems. There are, however, very limited data on relationships among resilience traits, childhood abuse, and alcohol or drug use problems. Hence, we aimed to examine associations between resilience characteristics and lifetime alcohol and illicit drug use in 2024 inner-city adults with high rates of childhood abuse and other trauma exposure. In this cross-sectional study, resilience was assessed with the Connor-Davidson Resilience Scale, childhood abuse with the Childhood Trauma Questionnaire, lifetime alcohol and illicit drug use with the Alcohol Use Disorder Identification Test and Drug Abuse Screening Test. Associations between resilience and substance use were examined with linear regression models, adjusting for trauma load, age, and sex. We found that resilience characteristics mitigated tendency for lifetime alcohol use problems both as a main effect (β = -0.11; p = 0.0014) and an interaction with severity of childhood abuse (β = -0.06; p = 0.0115) after trauma severity, age, and sex were controlled for. Similarly, resilience reduced lifetime illicit drug use both as a main effect (β = -0.03; p = 0.0008) and as an interaction with severity of childhood abuse (β = -0.01; p = 0.0256) after trauma load, age, and sex were adjusted for. Our findings add to a nascent body of literature suggesting that resilience characteristics mitigate risks not only for PTSD, major depression, and suicidality, but also for substance use problems in adults exposed to childhood abuse or other traumatic experiences. Published by Elsevier Ltd.

Achievable Performance and Effective Interrogator Design for SAW RFID Sensor Tags

NASA Technical Reports Server (NTRS)

Barton, Richard J.

2011-01-01

For many NASA missions, remote sensing is a critical application that supports activities such as environmental monitoring, planetary science, structural shape and health monitoring, non-destructive evaluation, etc. The utility of the remote sensing devices themselves is greatly increased if they are passive that is, they do not require any on-board power supply such as batteries and if they can be identified uniquely during the sensor interrogation process. Additional passive sensor characteristics that enable greater utilization in space applications are small size and weight, long read ranges with low interrogator power, ruggedness, and operability in extreme environments (vacuum, extreme high/low temperature, high radiation, etc.) In this paper, we consider one very promising passive sensor technology, called surface acoustic wave (SAW) radio-frequency identification (RFID), that satisfies all of these criteria. Although SAW RFID tags have great potential for use in numerous space-based remote sensing applications, the limited collision resolution capability of current generation tags limits the performance in a cluttered sensing environment. That is, as more SAW-based sensors are added to the environment, numerous tag responses are superimposed at the receiver and decoding all or even a subset of the telemetry becomes increasingly difficult. Background clutter generated by reflectors other than the sensors themselves is also a problem, as is multipath interference and signal distortion, but the limiting factor in many remote sensing applications can be expected to be tag mutual interference. This problem may be greatly mitigated by proper design of the SAW tag waveform, but that remains an open research problem, and in the meantime, several other related questions remain to be answered including: What are the fundamental relationships between tag parameters such as bit-rate, time-bandwidth-product, SNR, and achievable collision resolution? What are the differences in optimal or near-optimal interrogator designs between noise-limited environments and interference-limited environments? What are the performance characteristics of different interrogator designs in term of parameters such as transmitter power level, range, and number of interfering tags? In this paper, we present the results of a research effort aimed at providing at least partial answers to all of these questions.

The August Krogh principle applies to plants

NASA Technical Reports Server (NTRS)

Wayne, R.; Staves, M. P.

1996-01-01

The Krogh principle refers to the use of a large number of animals to study the large number of physiological problems, rather than limiting study to a particular organism for all problems. There may be organisms that are more suited to study of a particular problem than others. This same principle applies to plants. The authors are concerned with the recent trend in plant biology of using Arabidopsis thaliana as the "organism of choice." Arabidopsis is an excellent organism for molecular genetic research, but other plants are superior models for other research areas of plant biology. The authors present examples of the successful use of the Krogh principle in plant cell biology research, emphasizing the particular characteristics of the selected research organisms that make them the appropriate choice.

Vacuum pumps and systems: A review of current practice

NASA Technical Reports Server (NTRS)

Giles, Stuart

1986-01-01

A review of the fundamental characteristics of the many types of vacuum pumps and vacuum pumping systems is given. The optimum pumping range, relative cost, performance limitations, maintenance problems, system operating costs and similar subjects are discussed. Experiences from the thin film deposition, chemical processing, material handling, food processing and other industries, as well as space simulation are used to support conclusions and recommendations.

Human perceptual deficits as factors in computer interface test and evaluation

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

Bowser, S.E.

1992-06-01

Issues related to testing and evaluating human computer interfaces are usually based on the machine rather than on the human portion of the computer interface. Perceptual characteristics of the expected user are rarely investigated, and interface designers ignore known population perceptual limitations. For these reasons, environmental impacts on the equipment will more likely be defined than will user perceptual characteristics. The investigation of user population characteristics is most often directed toward intellectual abilities and anthropometry. This problem is compounded by the fact that some deficits capabilities tend to be found in higher-than-overall population distribution in some user groups. The testmore » and evaluation community can address the issue from two primary aspects. First, assessing user characteristics should be extended to include tests of perceptual capability. Secondly, interface designs should use multimode information coding.« less

Identification of Patient Zero in Static and Temporal Networks: Robustness and Limitations

NASA Astrophysics Data System (ADS)

Antulov-Fantulin, Nino; Lančić, Alen; Šmuc, Tomislav; Štefančić, Hrvoje; Šikić, Mile

2015-06-01

Detection of patient zero can give new insights to epidemiologists about the nature of first transmissions into a population. In this Letter, we study the statistical inference problem of detecting the source of epidemics from a snapshot of spreading on an arbitrary network structure. By using exact analytic calculations and Monte Carlo estimators, we demonstrate the detectability limits for the susceptible-infected-recovered model, which primarily depend on the spreading process characteristics. Finally, we demonstrate the applicability of the approach in a case of a simulated sexually transmitted infection spreading over an empirical temporal network of sexual interactions.

Changes of instability thresholds of rotor due to bearing misalignments

NASA Technical Reports Server (NTRS)

Springer, H.; Ecker, H.; Gunter, E. J.

1985-01-01

The influence of bearing misalignment upon the dynamic characteristics of statistically indeterminant rotor bearing systems is investigated. Both bearing loads and stability speed limits of a rotor may be changed significantly by magnitude and direction of bearing misalignment. The useful theory of short journal bearings is introduced and simple analytical expressions, governing the misalignment problem, are carried out. Polar plots for the bearing load capacities and stability maps, describing the speed limit in terms of misalignment, are presented. These plots can be used by the designer to estimate deviations between calculation and experimental data due to misalignment effects.

Behavioral Risk Assessment From Newborn to Preschool: The Value of Older Siblings.

PubMed

Rodrigues, Michelle; Binnoon-Erez, Noam; Plamondon, Andre; Jenkins, Jennifer M

2017-08-01

The aim of this study was to examine the plausibility of a risk prediction tool in infancy for school-entry emotional and behavioral problems. Familial aggregation has been operationalized previously as maternal psychopathology. The hypothesis was tested that older sibling (OS) psychopathology, as an indicator of familial aggregation, would enable a fair level of risk prediction compared with previous research, when combined with traditional risk factors. By using a longitudinal design, data on child and family risk factors were collected on 323 infants ( M = 2.00 months), all of whom had OSs. Infants were followed up 4.5 years later when both parents provided ratings of emotional and behavioral problems. Multiple regression and receiver operating characteristic curve analyses were conducted for emotional, conduct, and attention problems separately. The emotional and behavioral problems of OSs at infancy were the strongest predictors of the same problems in target children 4.5 years later. Other risk factors, including maternal depression and socioeconomic status provided extra, but weak, significant prediction. The area under the receiver operating characteristic curve for emotional and conduct problems yielded a fair prediction. This study is the first to offer a fair degree of prediction from risk factors at birth to school-entry emotional and behavioral problems. This degree of prediction was achieved with the inclusion of the emotional and behavioral problems of OSs (thus limiting generalizability to children with OSs). The inclusion of OS psychopathology raises risk prediction to a fair level. Copyright © 2017 by the American Academy of Pediatrics.

The relationship between physical and psychological complaints and quality of life in severely injured patients.

PubMed

van Delft-Schreurs, C C H M; van Son, M A C; de Jongh, M A C; Lansink, K W W; de Vries, J; Verhofstad, M H J

2017-09-01

The purpose of this study was two-fold. The first goal was to investigate which variables were associated with the remaining physical limitations of severely injured patients after the initial rehabilitation phase. Second, we investigated whether physical limitations were attributable to the association between psychological complaints and quality of life in this patient group. Patients who were 18 years or older and who had an injury severity score (ISS)>15 completed a set of questionnaires at one time-point after their rehabilitation phase (15-53 months after their trauma). The Short Musculoskeletal Function Assessment (SMFA) questionnaire was used to determine physical limitations. The Hospital Anxiety and Depression Scale, the Dutch Impact of Event Scale and the Cognitive Failure Questionnaire were used to determine psychological complaints, and the World Health Organization Quality of Life assessment instrument-BREF was used to measure general Quality of Life (QOL). Differences in physical limitations were investigated for several trauma- and patient-related variables using non-parametric independent-sample Mann-Whitney U tests. Multiple linear regression was performed to investigate whether the decreased QOL of severely injured patients with psychological complaints could be explained by their physical limitations. Older patients, patients with physical complaints before the injury, patients with higher ISS scores, and patients who had an injury of the spine or of the lower extremities reported significantly more physical problems. Additionally, patients with a low education level, patients who were living alone, and those who were unemployed reported significantly more long-term physical problems. Severely injured patients without psychological complaints reported significantly less physical limitations than those with psychological complaints. The SMFA factor of Lower extremity dysfunction was a confounder of the association between psychological complaints and QOL in all QOL domains. Long-term physical limitations were mainly reported by patients with psychological complaints. The decreased QOL of severely injured patients with psychological complaints can partially be explained by physical limitations, particularly those involving lower extremity function. Experienced physical limitations were significantly different for some trauma and patient characteristics. These characteristics may be used to select patients for whom a rehabilitation programme would be useful. Copyright © 2017. Published by Elsevier Ltd.

Constraint-based integration of planning and scheduling for space-based observatory management

NASA Technical Reports Server (NTRS)

Muscettola, Nicola; Smith, Steven F.

1994-01-01

Progress toward the development of effective, practical solutions to space-based observatory scheduling problems within the HSTS scheduling framework is reported. HSTS was developed and originally applied in the context of the Hubble Space Telescope (HST) short-term observation scheduling problem. The work was motivated by the limitations of the current solution and, more generally, by the insufficiency of classical planning and scheduling approaches in this problem context. HSTS has subsequently been used to develop improved heuristic solution techniques in related scheduling domains and is currently being applied to develop a scheduling tool for the upcoming Submillimeter Wave Astronomy Satellite (SWAS) mission. The salient architectural characteristics of HSTS and their relationship to previous scheduling and AI planning research are summarized. Then, some key problem decomposition techniques underlying the integrated planning and scheduling approach to the HST problem are described; research results indicate that these techniques provide leverage in solving space-based observatory scheduling problems. Finally, more recently developed constraint-posting scheduling procedures and the current SWAS application focus are summarized.

Rethinking Use of the OML Model in Electric Sail Development

NASA Technical Reports Server (NTRS)

Stone, Nobie H.

2016-01-01

In 1924, Irvin Langmuir and H. M. Mott-Smith published a theoretical model for the complex plasma sheath phenomenon in which they identified some very special cases which greatly simplified the sheath and allowed a closed solution to the problem. The most widely used application is for an electrostatic, or "Langmuir," probe in laboratory plasma. Although the Langmuir probe is physically simple (a biased wire) the theory describing its functional behavior and its current-voltage characteristic is extremely complex and, accordingly, a number of assumptions and approximations are used in the LMS model. These simplifications, correspondingly, place limits on the model's range of application. Adapting the LMS model to real-life conditions is the subject of numerous papers and dissertations. The Orbit-Motion Limited (OML) model that is widely used today is one of these adaptions that is a convenient means of calculating sheath effects. Since the Langmuir probe is a simple biased wire immersed in plasma, it is particularly tempting to use the OML equation in calculating the characteristics of the long, highly biased wires of an Electric Sail in the solar wind plasma. However, in order to arrive at the OML equation, a number of additional simplifying assumptions and approximations (beyond those made by Langmuir-Mott-Smith) are necessary. The OML equation is a good approximation when all conditions are met, but it would appear that the Electric Sail problem lies outside of the limits of applicability.

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

Deka, Deepjyoti; Backhaus, Scott N.; Chertkov, Michael

Limited placement of real-time monitoring devices in the distribution grid, recent trends notwithstanding, has prevented the easy implementation of demand-response and other smart grid applications. Part I of this paper discusses the problem of learning the operational structure of the grid from nodal voltage measurements. In this work (Part II), the learning of the operational radial structure is coupled with the problem of estimating nodal consumption statistics and inferring the line parameters in the grid. Based on a Linear-Coupled(LC) approximation of AC power flows equations, polynomial time algorithms are designed to identify the structure and estimate nodal load characteristics and/ormore » line parameters in the grid using the available nodal voltage measurements. Then the structure learning algorithm is extended to cases with missing data, where available observations are limited to a fraction of the grid nodes. The efficacy of the presented algorithms are demonstrated through simulations on several distribution test cases.« less

[Working conditions for supermarket employees: from experimental data to best practices].

PubMed

Martellotta, Francesco; Della Crociata, Sabrina; Simone, Antonio; Calderoni, Leonardo; D'Alba, Michele; Cervellati, Massimo; Papapietro, Nunzio

2014-07-15

Thermal, acoustic and visual comfort conditions for hypermarket workers have never been investigated with scientific methods. taking advantage of a case study, with characteristics capable of generalizing the results, analytically measure the actual comfort conditions to which workers are exposed and point out possible ameliorative proposals. Carry out a detailed survey based on instrumental measurements combined with subjective questionnaires to assess the indoor environment. Even though the analysis pointed out no significant risk conditions, several smaller problems appeared in terms of local discomfort (such as cold limbs, higher sound level exposure, limited glare phenomena) for cashier workers. The origin of these problems appeared to be the pivotal position of the cash registers. Taking into account observed phenomena and their causes a list of "best practices" has been defined hoping that their adoption could further limit any impact on workers comfort conditions.

Atmospheric Backscatter Model Development for CO Sub 2 Wavelengths

NASA Technical Reports Server (NTRS)

Deepak, A.; Kent, G.; Yue, G. K.

1982-01-01

The results of investigations into the problems of modeling atmospheric backscatter from aerosols, in the lowest 20 km of the atmosphere, at CO2 wavelengths are presented, along with a summary of the relevant aerosol characteristics and their variability, and a discussion of the measurement techniques and errors involved. The different methods of calculating the aerosol backscattering function, both from measured aerosol characteristics and from optical measurements made at other wavelengths, are discussed in detail, and limits are placed on the accuracy of these methods. The effects of changing atmospheric humidity and temperature on the backscatter are analyzed and related to the actual atmosphere. Finally, the results of modeling CO2 backscatter in the atmosphere are presented and the variation with height and geographic location discussed, and limits placed on the magnitude of the backscattering function. Conclusions regarding modeling techniques and modeled atmospheric backscatter values are presented in tabular form.

Shallow Reflection Method for Water-Filled Void Detection and Characterization

NASA Astrophysics Data System (ADS)

Zahari, M. N. H.; Madun, A.; Dahlan, S. H.; Joret, A.; Hazreek, Z. A. M.; Mohammad, A. H.; Izzaty, R. A.

2018-04-01

Shallow investigation is crucial in enhancing the characteristics of subsurface void commonly encountered in civil engineering, and one such technique commonly used is seismic-reflection technique. An assessment of the effectiveness of such an approach is critical to determine whether the quality of the works meets the prescribed requirements. Conventional quality testing suffers limitations including: limited coverage (both area and depth) and problems with resolution quality. Traditionally quality assurance measurements use laboratory and in-situ invasive and destructive tests. However geophysical approaches, which are typically non-invasive and non-destructive, offer a method by which improvement of detection can be measured in a cost-effective way. Of this seismic reflection have proved useful to assess void characteristic, this paper evaluates the application of shallow seismic-reflection method in characterizing the water-filled void properties at 0.34 m depth, specifically for detection and characterization of void measurement using 2-dimensional tomography.

Estimation of Snow Parameters from Dual-Wavelength Airborne Radar

NASA Technical Reports Server (NTRS)

Liao, Liang; Meneghini, Robert; Iguchi, Toshio; Detwiler, Andrew

1997-01-01

Estimation of snow characteristics from airborne radar measurements would complement In-situ measurements. While In-situ data provide more detailed information than radar, they are limited in their space-time sampling. In the absence of significant cloud water contents, dual-wavelength radar data can be used to estimate 2 parameters of a drop size distribution if the snow density is assumed. To estimate, rather than assume, a snow density is difficult, however, and represents a major limitation in the radar retrieval. There are a number of ways that this problem can be investigated: direct comparisons with in-situ measurements, examination of the large scale characteristics of the retrievals and their comparison to cloud model outputs, use of LDR measurements, and comparisons to the theoretical results of Passarelli(1978) and others. In this paper we address the first approach and, in part, the second.

[The present and future state of minimized extracorporeal circulation].

PubMed

Meng, Fan; Yang, Ming

2013-05-01

Minimized extracorporeal circulation improved in the postoperative side effects of conventional extracorporeal circulation is a kind of new extracorporeal circulation. This paper introduces the principle, characteristics, applications and related research of minimized extracorporeal circulation. For the problems of systemic inflammatory response syndrome and limited assist time, the article proposes three development direction including system miniaturization and integration, pulsatile blood pump and the adaptive control by human parameter identification.

Planar-Processed Polymer Transistors.

PubMed

Xu, Yong; Sun, Huabin; Shin, Eul-Yong; Lin, Yen-Fu; Li, Wenwu; Noh, Yong-Young

2016-10-01

Planar-processed polymer transistors are proposed where the effective charge injection and the split unipolar charge transport are all on the top surface of the polymer film, showing ideal device characteristics with unparalleled performance. This technique provides a great solution to the problem of fabrication limitations, the ambiguous operating principle, and the performance improvements in practical applications of conjugated-polymer transistors. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Computerized symbolic manipulation in structural mechanics Progress and potential

NASA Technical Reports Server (NTRS)

Noor, A. K.; Andersen, C. M.

1978-01-01

Status and recent applications of computerized symbolic manipulation to structural mechanics problems are summarized. The applications discussed include; (1) generation of characteristic arrays of finite elements; (2) evaluation of effective stiffness and mass coefficients of continuum models for repetitive lattice structures; and (3) application of Rayleigh-Ritz technique to free vibration analysis of laminated composite elliptic plates. The major advantages of using computerized symbolic manipulation in each of these applications are outlined. A number of problem areas which limit the realization of the full potential of computerized symbolic manipulation in structural mechanics are examined and some of the means of alleviating them are discussed.

Propagation of sound in turbulent media

NASA Technical Reports Server (NTRS)

Wenzel, A. R.

1976-01-01

Perturbation methods commonly used to study the propagation of acoustic waves in turbulent media are reviewed. Emphasis is on those techniques which are applicable to problems involving long-range propagation in the atmosphere and ocean. Characteristic features of the various methods are illustrated by applying them to particular problems. It is shown that conventional perturbation techniques, such as the Born approximation, yield solutions which contain secular terms, and which therefore have a relatively limited range of validity. In contrast, it is found that solutions obtained with the aid of the Rytov method or the smoothing method do not contain secular terms, and consequently have a much greater range of validity.

Research on resistance characteristics of YBCO tape under short-time DC large current impact

NASA Astrophysics Data System (ADS)

Zhang, Zhifeng; Yang, Jiabin; Qiu, Qingquan; Zhang, Guomin; Lin, Liangzhen

2017-06-01

Research of the resistance characteristics of YBCO tape under short-time DC large current impact is the foundation of the developing DC superconducting fault current limiter (SFCL) for voltage source converter-based high voltage direct current system (VSC-HVDC), which is one of the valid approaches to solve the problems of renewable energy integration. SFCL can limit DC short-circuit and enhance the interrupting capabilities of DC circuit breakers. In this paper, under short-time DC large current impacts, the resistance features of naked tape of YBCO tape are studied to find the resistance - temperature change rule and the maximum impact current. The influence of insulation for the resistance - temperature characteristics of YBCO tape is studied by comparison tests with naked tape and insulating tape in 77 K. The influence of operating temperature on the tape is also studied under subcooled liquid nitrogen condition. For the current impact security of YBCO tape, the critical current degradation and top temperature are analyzed and worked as judgment standards. The testing results is helpful for in developing SFCL in VSC-HVDC.

Friends with benefits: the evolved psychology of same- and opposite-sex friendship.

PubMed

Lewis, David M G; Conroy-Beam, Daniel; Al-Shawaf, Laith; Raja, Annia; DeKay, Todd; Buss, David M

2011-12-08

During human evolution, men and women faced distinct adaptive problems, including pregnancy, hunting, childcare, and warfare. Due to these sex-linked adaptive problems, natural selection would have favored psychological mechanisms that oriented men and women toward forming friendships with individuals possessing characteristics valuable for solving these problems. The current study explored sex-differentiated friend preferences and the psychological design features of same- and opposite-sex friendship in two tasks. In Task 1, participants (N = 121) categorized their same-sex friends (SSFs) and opposite-sex friends (OSFs) according to the functions these friends serve in their lives. In Task 2, participants designed their ideal SSFs and OSFs using limited budgets that forced them to make trade-offs between the characteristics they desire in their friends. In Task 1, men, more than women, reported maintaining SSFs for functions related to athleticism and status enhancement and OSFs for mating opportunities. In Task 2, both sexes prioritized agreeableness and dependability in their ideal SSFs, but men prioritized physical attractiveness in their OSFs, whereas women prioritized economic resources and physical prowess. These findings suggest that friend preferences may have evolved to solve ancestrally sex-linked adaptive problems, and that opposite-sex friendship may directly or indirectly serve mating functions.

Negative emotionality and externalizing problems in toddlerhood: overreactive parenting as a moderator of genetic influences.

PubMed

Lipscomb, Shannon T; Leve, Leslie D; Shaw, Daniel S; Neiderhiser, Jenae M; Scaramella, Laura V; Ge, Xiaojia; Conger, Rand D; Reid, John B; Reiss, David

2012-02-01

The current study examines the interplay between parental overreactivity and children's genetic backgrounds as inferred from birth parent characteristics on the development of negative emotionality during infancy, and in turn, to individual differences in externalizing problems in toddlerhood. The sample included 361 families linked through adoption (birth parents and adoptive families). Data were collected when the children were 9, 18, and 27 months old. Results indicated links between individual levels and changes in negative emotionality during infancy and toddlerhood to externalizing problems early in the third year of life. Findings also revealed an interaction between birth mother negative affect and adoptive mother overreactive parenting on children's negative emotionality. This Genotype × Environment interaction predicted externalizing problems indirectly through its association with negative emotionality and revealed stronger effects of genetic risk for children with less overreactive parenting from their mothers. Limitations of this study and directions for future research are discussed.

Testing Alternative Explanations for the Associations Between Parenting and Adolescent Suicidal Problems

PubMed Central

Boeninger, Daria K.; Masyn, Katherine E.; Conger, Rand D.

2012-01-01

Although studies have established associations between parenting characteristics and adolescent suicidality, the strength of the evidence for these links remains unclear, largely because of methodological limitations, including lack of accounting for possible child effects on parenting. This study addresses these issues by using autoregressive cross-lag models with data on 802 adolescents and their parents across 5 years. Observed parenting behaviors predicted change in adolescent suicidal problems across one-year intervals even after controlling for adolescents’ effects on parenting. Nurturant-involved parenting continued to demonstrate salutary effects after controlling for adolescent and parent internalizing psychopathology: over time, observed nurturant-involved parenting reduced the likelihood of adolescent suicidal problems. This study increases the empirical support implicating parenting behaviors in the developmental course of adolescent suicidality. PMID:24244079

Understanding Who Benefits from Parenting Interventions for Children's Conduct Problems: an Integrative Data Analysis.

PubMed

Leijten, Patty; Raaijmakers, Maartje; Wijngaards, Leoniek; Matthys, Walter; Menting, Ankie; Hemink-van Putten, Maud; Orobio de Castro, Bram

2018-05-01

Parenting interventions are an effective strategy to reduce children's conduct problems. For some families, that is, not all families benefit equally. Individual trials tend to be underpowered and often lack variability to differentiate between families how benefit less or more. Integrating individual family level data across trials, we aimed to provide more conclusive results about often presumed key family (parental education and ethnic background) and child characteristics (problem severity, ADHD symptoms and emotional problems) as putative moderators of parenting intervention effects. We included data from 786 families (452 intervention; 334 control) from all four trials on the Incredible Years parenting intervention in The Netherlands (three randomized; one matched control). Children ranged between 2 and 10 years (M = 5.79; SD = 1.66). Of the families, 31% had a lower educational level and 29% had an ethnic minority background. Using multilevel regression, we tested whether each of the putative moderators affected intervention effects. Incredible Years reduced children's conduct problems (d = - .34). There were no differential effects by families' educational or ethnic background, or by children's level of ADHD symptoms. Children with more severe conduct problems and those with more emotional problems benefited more. Post hoc sensitivity analyses showed that for the two trials with longer-term data, moderation effects disappeared at 4 or 12 months follow-up. Often assumed moderators have some, but limited abilities to explain who benefits from parenting interventions. This suggests the need for studying theoretically more precise moderators in prevention research, other than relatively static family characteristics alone.

Uncovering factors affecting use of the emergency department for less urgent health problems in urban and rural areas.

PubMed

Hodgins, Marilyn J; Wuest, Judith

2007-09-01

People who access the emergency department for less urgent health problems have been described as inappropriate users of the health-care system.Yet little is known about the factors precipitating such use and how these differ based on location of the emergency department. In this descriptive-correlational study guided by Andersen's Model of Health Services Use, 1612 people who presented to an emergency department with a less urgent health problem were interviewed. Analysis revealed rural/urban differences in the characteristics of patients, nature of the problems, actions taken, and factors precipitating the visit. Despite its popularity, the predictive capabilities of Andersen's model were limited in explaining use of self-treatment or willingness to wait for treatment. The findings show that an emergency department's roles and functions vary according to its location. Such insights provide direction for developing services that respond to the needs of people with less urgent health problems that are cognizant of geographic location.

A knowledge engineering taxonomy for intelligent tutoring system development

NASA Technical Reports Server (NTRS)

Fink, Pamela K.; Herren, L. Tandy

1993-01-01

This paper describes a study addressing the issue of developing an appropriate mapping of knowledge acquisition methods to problem types for intelligent tutoring system development. Recent research has recognized that knowledge acquisition methodologies are not general across problem domains; the effectiveness of a method for obtaining knowledge depends on the characteristics of the domain and problem solving task. Southwest Research Institute developed a taxonomy of problem types by evaluating the characteristics that discriminate between problems and grouping problems that share critical characteristics. Along with the problem taxonomy, heuristics that guide the knowledge acquisition process based on the characteristics of the class are provided.

Correlation between UV and IR cutoffs in quantum field theory and large extra dimensions

NASA Astrophysics Data System (ADS)

Cortés, J. L.

1999-04-01

A recently conjectured relationship between UV and IR cutoffs in an effective field theory without quantum gravity is generalized in the presence of large extra dimensions. Estimates for the corrections to the usual calculation of observables within quantum field theory are used to put very stringent limits, in some cases, on the characteristic scale of the additional compactified dimensions. Implications for the cosmological constant problem are also discussed.

Comprehensive helicopter analysis: A state of the art review

NASA Technical Reports Server (NTRS)

Johnson, W.

1978-01-01

An assessment of the status of helicopter theory and analysis is presented. The technology level embodied in available design tools (computer programs) is examined, considering the problem areas of performance, loads and vibration, handling qualities and simulation, and aeroelastic stability. The effectiveness of the present analyses is discussed. The characteristics of the technology in the analyses are reviewed, including the aerodynamics technology, induced velocity and wake geometry, dynamics technology, and machine limitations.

Diffusion Characteristics of Upwind Schemes on Unstructured Triangulations

NASA Technical Reports Server (NTRS)

Wood, William A.; Kleb, William L.

1998-01-01

The diffusive characteristics of two upwind schemes, multi-dimensional fluctuation splitting and dimensionally-split finite volume, are compared for scalar advection-diffusion problems. Algorithms for the two schemes are developed for node-based data representation on median-dual meshes associated with unstructured triangulations in two spatial dimensions. Four model equations are considered: linear advection, non-linear advection, diffusion, and advection-diffusion. Modular coding is employed to isolate the effects of the two approaches for upwind flux evaluation, allowing for head-to-head accuracy and efficiency comparisons. Both the stability of compressive limiters and the amount of artificial diffusion generated by the schemes is found to be grid-orientation dependent, with the fluctuation splitting scheme producing less artificial diffusion than the dimensionally-split finite volume scheme. Convergence rates are compared for the combined advection-diffusion problem, with a speedup of 2-3 seen for fluctuation splitting versus finite volume when solved on the same mesh. However, accurate solutions to problems with small diffusion coefficients can be achieved on coarser meshes using fluctuation splitting rather than finite volume, so that when comparing convergence rates to reach a given accuracy, fluctuation splitting shows a 20-25 speedup over finite volume.

Online gambling's moderators: how effective? Study protocol for a randomized controlled trial.

PubMed

Caillon, Julie; Grall-Bronnec, Marie; Hardouin, Jean-Benoit; Venisse, Jean-Luc; Challet-Bouju, Gaelle

2015-05-30

Online gambling has been legalized in France in 2010. Licenses are issued to gambling operators who demonstrate their ability to respect the legal framework (security, taxation, consumer protection, etc.). The preventive measures to protect vulnerable gamblers include an obligation to provide online gambling moderators. These moderators should allow gamblers to limit their bets, exclude themselves from the website for 7 days, and consult the balance of the gambler's account at any time. However, there are only a few published reports of empirical research investigating the effectiveness of Internet-based protective measures implemented by French law. Moreover, no empirical research has yet studied the impact of bonuses on gambling behaviors. This research is an experimental randomized controlled trial, risk prevention targeted. The research is divided into four sub-studies depending on the studied moderator: limiting bonuses, self-exclusion, self-limitation and information. The study sample consists of 485 volunteers. For each experimental condition and the control groups, the sample is composed of gamblers equally recruited from gamblers having preferences in each of the three major forms of games (lottery and scratch tickets, sports and horserace betting, and poker). For each form of gambling, the gamblers are recruited in order to obtain as many problem gamblers as non-problem gamblers. According to the randomization, the experimental session begins. The experimental session is a gambling situation on a computer in our research center. The gambler is invited to play on his favorite gambling site as usual, with his own gambler account and his own money. Data collected comprise sociodemographic characteristics, gambling habits, an interview about enjoyment and feeling out of control during the gambling session, moderator impact on gambling practice, statement of gambling parameters and questionnaires (BMIS, GRCS, CPGI, GACS). Moderator efficiency is assessed based on the two major characteristics of gambling behavior: money wagered and time spent in gambling. The results of this research will be important to prevent online problem gambling and influence policy-makers. NCT01789580. Registered 8 February 2013.

Assessing adaptation to the health risks of climate change: what guidance can existing frameworks provide?

PubMed

Füssel, Hans-Martin

2008-02-01

Climate change adaptation assessments aim at assisting policy-makers in reducing the health risks associated with climate change and variability. This paper identifies key characteristics of the climate-health relationship and of the adaptation decision problem that require consideration in climate change adaptation assessments. It then analyzes whether these characteristics are appropriately considered in existing guidelines for climate impact and adaptation assessment and in pertinent conceptual models from environmental epidemiology. The review finds three assessment guidelines based on a generalized risk management framework to be most useful for guiding adaptation assessments of human health. Since none of them adequately addresses all key challenges of the adaptation decision problem, actual adaptation assessments need to combine elements from different guidelines. Established conceptual models from environmental epidemiology are found to be of limited relevance for assessing and planning adaptation to climate change since the prevailing toxicological model of environmental health is not applicable to many climate-sensitive health risks.

A review of the supply of liquid propellants and other fluids in support of the Space Shuttle Program

NASA Technical Reports Server (NTRS)

Churchwell, Stacy E.; Bain, A. L.

1989-01-01

In this study, over twenty significant liquid propellants and other fluids were reviewed as to their supply in support of the Space Shuttle Program (SSP), primarily at KSC. The uniqueness of most of the products, either by their application or production characteristics, present a variety of supply issues to contend with. Each, however, is critical to the success of the SSP. It becomes necessary to formulate, and maintain, a logistic approach to assure a continued availability of each product. For convenience, two categories were established. One, labeled limited-availability, represents those products wherein they are single sourced, have production restrictions and/or there has been a history of supply problems. The other, labeled universally-available, is characteristic of those having several sources and/or having little, if any, historical supply problems. This last category was not examined in depth. Through concepts of establishing stockpile inventories, multiple supply contracts, or other arrangements, the supply of liquid propellants and other fluids can be assured.

Characteristics of lesbian, gay, bisexual, and transgender individuals entering substance abuse treatment.

PubMed

Cochran, Bryan N; Cauce, Ana Mari

2006-03-01

Previous research has suggested that lesbian, gay, bisexual, and transgender (LGBT) individuals enter treatment for substance abuse with more severe problems than heterosexual individuals. However, methodological difficulties, particularly the difficulty of obtaining a representative sample, have limited the ability to draw conclusions about LGBT individuals who receive services for substance abuse. This study took advantage of a unique opportunity to examine a representative sample of openly LGBT clients receiving publicly funded substance abuse treatment by using data gathered by treatment providers in Washington State. Baseline differences between openly LGBT and heterosexual clients were compared in a variety of domains. Results demonstrated that openly LGBT clients enter treatment with more severe substance abuse problems, greater psychopathology, and greater medical service utilization when compared with heterosexual clients. When the analyses were stratified based on sex, different patterns of substance use and associated psychosocial characteristics emerged for the LGBT clients. Implications for provision of appropriate services and recommendations to treatment agencies are discussed in this article.

A new approach to impulsive rendezvous near circular orbit

NASA Astrophysics Data System (ADS)

Carter, Thomas; Humi, Mayer

2012-04-01

A new approach is presented for the problem of planar optimal impulsive rendezvous of a spacecraft in an inertial frame near a circular orbit in a Newtonian gravitational field. The total characteristic velocity to be minimized is replaced by a related characteristic-value function and this related optimization problem can be solved in closed form. The solution of this problem is shown to approach the solution of the original problem in the limit as the boundary conditions approach those of a circular orbit. Using a form of primer-vector theory the problem is formulated in a way that leads to relatively easy calculation of the optimal velocity increments. A certain vector that can easily be calculated from the boundary conditions determines the number of impulses required for solution of the optimization problem and also is useful in the computation of these velocity increments. Necessary and sufficient conditions for boundary conditions to require exactly three nonsingular non-degenerate impulses for solution of the related optimal rendezvous problem, and a means of calculating these velocity increments are presented. A simple example of a three-impulse rendezvous problem is solved and the resulting trajectory is depicted. Optimal non-degenerate nonsingular two-impulse rendezvous for the related problem is found to consist of four categories of solutions depending on the four ways the primer vector locus intersects the unit circle. Necessary and sufficient conditions for each category of solutions are presented. The region of the boundary values that admit each category of solutions of the related problem are found, and in each case a closed-form solution of the optimal velocity increments is presented. Similar results are presented for the simpler optimal rendezvous that require only one-impulse. For brevity degenerate and singular solutions are not discussed in detail, but should be presented in a following study. Although this approach is thought to provide simpler computations than existing methods, its main contribution may be in establishing a new approach to the more general problem.

Effects of structural and dynamic family characteristics on the development of depressive and aggressive problems during adolescence. The TRAILS study.

PubMed

Sijtsema, J J; Oldehinkel, A J; Veenstra, R; Verhulst, F C; Ormel, J

2014-06-01

Both structural (i.e., SES, familial psychopathology, family composition) and dynamic (i.e., parental warmth and rejection) family characteristics have been associated with aggressive and depressive problem development. However, it is unclear to what extent (changes in) dynamic family characteristics have an independent effect on problem development while accounting for stable family characteristics and comorbid problem development. This issue was addressed by studying problem development in a large community sample (N = 2,230; age 10-20) of adolescents using Linear Mixed models. Paternal and maternal warmth and rejection were assessed via the Egna Minnen Beträffande Uppfostran for Children (EMBU-C). Aggressive and depressive problems were assessed via subscales of the Youth/Adult Self-Report. Results showed that dynamic family characteristics independently affected the development of aggressive problems. Moreover, maternal rejection in preadolescence and increases in paternal rejection were associated with aggressive problems, whereas decreases in maternal rejection were associated with decreases in depressive problems over time. Paternal and maternal warmth in preadolescence was associated with fewer depressive problems during adolescence. Moreover, increases in paternal warmth were associated with fewer depressive problems over time. Aggressive problems were a stable predictor of depressive problems over time. Finally, those who increased in depressive problems became more aggressive during adolescence, whereas those who decreased in depressive problems became also less aggressive. Besides the effect of comorbid problems, problem development is to a large extent due to dynamic family characteristics, and in particular to changes in parental rejection, which leaves much room for parenting-based interventions.

Aeroelasticity and mechanical stability report, 0.27 Mach scale model of the YAH-64 advanced attack helicopter

NASA Technical Reports Server (NTRS)

Straub, F. K.; Johnston, R. A.

1987-01-01

A 27% dynamically scaled model of the YAH-64 Advanced Attack Helicopter main rotor and hub has been designed and fabricated. The model will be tested in the NASA Langley Research Center V/STOL wind tunnel using the General Rotor Model System (GRMS). This report documents the studies performed to ensure dynamic similarity of the model with its full scale parent. It also contains a preliminary aeroelastic and aeromechanical substantiation for the rotor installation in the wind tunnel. From the limited studies performed no aeroelastic stability or load problems are projected. To alleviate a projected ground resonance problem, a modification of the roll characteristics of the GRMS is recommended.

Foot Plantar Pressure Measurement System: A Review

PubMed Central

Razak, Abdul Hadi Abdul; Zayegh, Aladin; Begg, Rezaul K.; Wahab, Yufridin

2012-01-01

Foot plantar pressure is the pressure field that acts between the foot and the support surface during everyday locomotor activities. Information derived from such pressure measures is important in gait and posture research for diagnosing lower limb problems, footwear design, sport biomechanics, injury prevention and other applications. This paper reviews foot plantar sensors characteristics as reported in the literature in addition to foot plantar pressure measurement systems applied to a variety of research problems. Strengths and limitations of current systems are discussed and a wireless foot plantar pressure system is proposed suitable for measuring high pressure distributions under the foot with high accuracy and reliability. The novel system is based on highly linear pressure sensors with no hysteresis. PMID:23012576

The NASA Altitude Wind Tunnel (AWT): Its role in advanced icing research and development

NASA Technical Reports Server (NTRS)

Blaha, B. J.; Shaw, R. J.

1985-01-01

Currently experimental aircraft icing research is severely hampered by limitations of ground icing simulation facilities. Existing icing facilities do not have the size, speed, altitude, and icing environment simulation capabilities to allow accurate studies to be made of icing problems occurring for high speed fixed wing aircraft and rotorcraft. Use of the currently dormant NASA Lewis Altitude Wind Tunnel (AWT), as a proposed high speed propulsion and adverse weather facility, would allow many such problems to be studied. The characteristics of the AWT related to adverse weather simulation and in particular to icing simulation are discussed, and potential icing research programs using the AWT are also included.

Rosalie Wolf Memorial Lecture: Reconsidering assumptions regarding men as elder abuse perpetrators and as elder abuse victims.

PubMed

Kosberg, Jordan I

2014-01-01

From research findings and practice experiences, it is concluded that abuse of older men is especially invisible and underreported, compared to abuse of older women. It is proposed that attention should be directed not to gender, but to those conditions in different countries and cultures leading to abuse of both older men and women, including (but not limited to) economic problems, few alternatives to family care of the elderly, violence, changing characteristics of the family, ageism, and sexism. Advocates for the prevention of elder abuse should work together in combating, reducing, and eliminating the problem of elder abuse of both older men and older women.

Dynamic characteristics of a variable-mass flexible missile: Dynamics of a two-stage variable-mass flexible rocket

NASA Technical Reports Server (NTRS)

Meirovitch, L.; Bankovskis, J.

1969-01-01

The dynamic characteristics of two-stage slender elastic body were investigated. The first stage, containing a solid-fuel rocket, possesses variable mass while the second stage, envisioned as a flexible case, contains packaged instruments of constant mass. The mathematical formulation was in terms of vector equations of motion transformed by a variational principle into sets of scalar differential equations in terms of generalized coordinates. Solutions to the complete equations were obtained numerically by means of finite difference techniques. The problem has been programmed in the FORTRAN 4 language and solved on an IBM 360/50 computer. Results for limited cases are presented showing the nature of the solutions.

Synthesis of correlation filters: a generalized space-domain approach for improved filter characteristics

NASA Astrophysics Data System (ADS)

Sudharsanan, Subramania I.; Mahalanobis, Abhijit; Sundareshan, Malur K.

1990-12-01

Discrete frequency domain design of Minimum Average Correlation Energy filters for optical pattern recognition introduces an implementational limitation of circular correlation. An alternative methodology which uses space domain computations to overcome this problem is presented. The technique is generalized to construct an improved synthetic discriminant function which satisfies the conflicting requirements of reduced noise variance and sharp correlation peaks to facilitate ease of detection. A quantitative evaluation of the performance characteristics of the new filter is conducted and is shown to compare favorably with the well known Minimum Variance Synthetic Discriminant Function and the space domain Minimum Average Correlation Energy filter, which are special cases of the present design.

Visual analysis as a method of interpretation of the results of satellite ionospheric measurements for exploratory problems

NASA Astrophysics Data System (ADS)

Korneva, N. N.; Mogilevskii, M. M.; Nazarov, V. N.

2016-05-01

Traditional methods of time series analysis of satellite ionospheric measurements have some limitations and disadvantages that are mainly associated with the complex nonstationary signal structure. In this paper, the possibility of identifying and studying the temporal characteristics of signals via visual analysis is considered. The proposed approach is illustrated by the example of the visual analysis of wave measurements on the DEMETER microsatellite during its passage over the HAARP facility.

PUBLIC POLICY ISSUES, REPLY LEGAL BRIEF, AND TECHNICAL AND ECONOMIC DATA, BEFORE THE FEDERAL COMMUNICATIONS COMMISSION, IN THE MATTER OF THE ESTABLISHMENT OF DOMESTIC COMMUNICATIONS SATELLITE FACILITIES BY NON-GOVERNMENTAL ENTITIES, DOCKET 16495.

ERIC Educational Resources Information Center

Ford Foundation, New York, NY.

THE THREE PARTS OF THIS FORD FUNDATION SUBMISSION PROVIDE INFORMATION ON BROAD ISSUES OF ORGANIZATION AND PUBLIC POLICY AS THEY RELATE TO SATELLITE MODEL SYSTEMS BNS-3 AND BNS-4, ON LEGAL PROBLEMS OF AUTHORIZATION AND CONTROL, AND ON THE TECHNICAL CHARACTERISTICS, COSTS, AND BROADCAST SPECTRUM LIMITATIONS OF EACH SYSTEM. VOLUME I OUTLINES…

Progress and needs in agricultural research, development, and applications programs

NASA Technical Reports Server (NTRS)

Moore, D. G.; Myers, V. I.

1977-01-01

The dynamic nature of agriculture requires repetitive resource assessments such as those from remote sensing. Until recently, the use of remote sensing in agriculture has been limited primarily to site specific investigations without large-scale evaluations. Examples of successful applications at various user levels are provided. The stage of development for applying remote sensing to many agricultural problems is assessed, and goals for planning future data characteristics for increased use in agriculture are suggested.

[A health survey in riverine communities in Amazonas State, Brazil].

PubMed

Gama, Abel Santiago Muri; Fernandes, Tiótrefis Gomes; Parente, Rosana Cristina Pereira; Secoli, Silvia Regina

2018-02-19

Population-based health surveys are important tools for identifying disease determinants, especially in regions with widely dispersed populations and low health system coverage. The aim of this study was to describe the principal methodological aspects and to describe the socioeconomic, demographic, and health characteristics of the riverine populations of Coari, Amazonas State, Brazil. This was a population-based cross-sectional study in river-dwelling communities in the rural area of Coari, from April to July 2015. The probabilistic cluster sample consisted of 492 individuals. The results showed that the majority of the river-dwellers were females (53%), had up to 9 years of schooling (68.5%), and earned a monthly family income equivalent to one-third the minimum wage. The health problems reported in the previous 30 days featured conditions involving pain (45.2%). The main healthcare resources were allopathic medicines (70.3%), exceeding herbal remedies (44.3%). The river-dwellers travel an average of 60.4km and take some 4.2 hours to reach the urban area of Coari. The riverine population generally presents low economic status and limited access to the urban area. Health problems are mostly solved with allopathic medicines. Geographic characteristics, as barriers to access to health services and to improvements in living conditions for the riverine population, can limit the collection of epidemiological data on these populations.

Effects of a finite aperture on the Inverse Born Approximation

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

Kogan, V.G.; Rose, J.H.

1983-01-01

One of the most important effects of complex part geometry is that the available entrance and exit angles for ultrasound are limited. We will present a study of the Inverse Born approximation in which we have data for incident (and exit) directions confined to a conical aperture. Modeling the direct problem by the Born Approximation, we obtained analytical results for (1) a weak spherical inclusion, and (2) a penny shaped crack (modeled by an oblate spheroid). General results are: (a) the value of the characteristic function ..gamma.. is constant in the interior of the flaw, but reduced in value; (b)more » the discontinuity at the boundary of the flaw occurs over the lighted portion of the flaw; (c) this discontinuity is contrasted by a region where ..gamma.. is negative; and (d) new non-physical discontinuities and non-analyticities appear in the reconstructed characteristic function. These general features also appear in numerical calculations which use as input strong scattering data from a spherical void and a flat penny shaped crack in Titanium. The numerical results can be straightforwardly interpreted in terms of the analytical calculation mentioned above, indicating that they will be useful in the study of realistic flaws. We conclude by discussing the stabilization of the aperture limited inversion problem and the removal of non-physical features in the reconstruction.« less

Designing 4H-SiC P-shielding trench gate MOSFET to optimize on-off electrical characteristics

NASA Astrophysics Data System (ADS)

Kyoung, Sinsu; Hong, Young-sung; Lee, Myung-hwan; Nam, Tae-jin

2018-02-01

In order to enhance specific on-resistance (Ron,sp), the trench gate structure was also introduced into 4H-SiC MOSFET as Si MOSFET. But the 4H-SiC trench gate has worse off-state characteristics than the Si trench gate due to the incomplete gate oxidation process (Šimonka et al., 2017). In order to overcome this problem, P-shielding trench gate MOSFET (TMOS) was proposed and researched in previous studies. But P-shielding has to be designed with minimum design rule in order to protect gate oxide effectively. P-shielding TMOS also has the drawback of on-state characteristics degradation corresponding to off state improvement for minimum design rule. Therefore optimized design is needed to satisfy both on and off characteristics. In this paper, the design parameters were analyzed and optimized so that the 4H-SiC P-shielding TMOS satisfies both on and off characteristics. Design limitations were proposed such that P-shielding is able to defend the gate oxide. The P-shielding layer should have the proper junction depth and concentration to defend the electric field to gate oxide during the off-state. However, overmuch P-shielding junction depth disturbs the on-state current flow, a problem which can be solved by increasing the trench depth. As trench depth increases, however, the breakdown voltage decreases. Therefore, trench depth should be designed with due consideration for on-off characteristics. For this, design conditions and modeling were proposed which allow P-shielding to operate without degradation of on-state characteristics. Based on this proposed model, the 1200 V 4H-SiC P-shielding trench gate MOSFET was designed and optimized.

Improvement of Thrust Characteristics of Helicon Plasma Thruster using Local Gas Fueling Method

NASA Astrophysics Data System (ADS)

Kuwahara, Daisuke; Amma, Kosuke; Ishigami, Yuichi; Igarashi, Akihiko; Nishimoto, Shinichi; Shinohara, Shunjiro; Miyazawa, Junichi

2017-10-01

A helicon plasma thruster is proposed as a long-lifetime electric thruster which has non-direct contact electrodes. Here, a neutral particle, e.g., H2, Ar, and Xe works, as a fuel gas. In most cases, these gases are supplied into a discharge tube by the use of a simple nozzle. Therefore, the neutral particle fills a discharge tube homogenous. However, there are two problems in this configuration. First, there is a limitation of an electron density increase, due to a neutral particle depletion in the central region of the high-density helicon plasma. This limitation reduces the thrust performance directly. Second, the high-density plasma causes an erosion of an inner discharge tube wall. For the future MW class thruster, this problem will become serious because the particle and heat fluxes of the plasma will increase drastically. To solve above-mentioned problems, we have proposed local fueling methods for the high-density helicon plasma. In this presentation, we will show the methods and experimental results using a fueling tube, inserted in a plasma directly. This work is supported by JSPS KAKENHI Grant Number 16K17843 and NIFS Collaboration Research program (NIFSKBAF016).

Lattice Boltzmann scheme for mixture modeling: analysis of the continuum diffusion regimes recovering Maxwell-Stefan model and incompressible Navier-Stokes equations.

PubMed

Asinari, Pietro

2009-11-01

A finite difference lattice Boltzmann scheme for homogeneous mixture modeling, which recovers Maxwell-Stefan diffusion model in the continuum limit, without the restriction of the mixture-averaged diffusion approximation, was recently proposed [P. Asinari, Phys. Rev. E 77, 056706 (2008)]. The theoretical basis is the Bhatnagar-Gross-Krook-type kinetic model for gas mixtures [P. Andries, K. Aoki, and B. Perthame, J. Stat. Phys. 106, 993 (2002)]. In the present paper, the recovered macroscopic equations in the continuum limit are systematically investigated by varying the ratio between the characteristic diffusion speed and the characteristic barycentric speed. It comes out that the diffusion speed must be at least one order of magnitude (in terms of Knudsen number) smaller than the barycentric speed, in order to recover the Navier-Stokes equations for mixtures in the incompressible limit. Some further numerical tests are also reported. In particular, (1) the solvent and dilute test cases are considered, because they are limiting cases in which the Maxwell-Stefan model reduces automatically to Fickian cases. Moreover, (2) some tests based on the Stefan diffusion tube are reported for proving the complete capabilities of the proposed scheme in solving Maxwell-Stefan diffusion problems. The proposed scheme agrees well with the expected theoretical results.

Swimming in the USA: beachgoer characteristics and health outcomes at US marine and freshwater beaches

PubMed Central

Collier, Sarah A.; Wade, Timothy J.; Sams, Elizabeth A.; Hlavsa, Michele C.; Dufour, Alfred P.; Beach, Michael J.

2015-01-01

Swimming in lakes and oceans is popular, but little is known about the demographic characteristics, behaviors, and health risks of beachgoers on a national level. Data from a prospective cohort study of beachgoers at multiple marine and freshwater beaches in the USA were used to describe beachgoer characteristics and health outcomes for swimmers and non-swimmers. This analysis included 54,250 participants. Most (73.2%) entered the water; of those, 65.1% put their head under water, 41.3% got water in their mouth and 18.5% swallowed water. Overall, 16.3% of beachgoers reported any new health problem. Among swimmers, 6.6% reported gastrointestinal (GI) illness compared with 5.5% of non-swimmers (unadjusted χ2 p < 0.001); 6.0% of swimmers and 4.9% of non-swimmers reported respiratory illness (p < 0.001); 1.8% of swimmers and 1.0% of non-swimmers reported ear problems (p < 0.001); and 3.9% of swimmers and 2.4% of non-swimmers experienced a rash (p < 0.001). Overall, swimmers reported a higher unadjusted incidence of GI illness and earaches than non-swimmers. Current surveillance systems might not detect individual cases and outbreaks of illness associated with swimming in natural water. Better knowledge of beachgoer characteristics, activities, and health risks associated with swimming in natural water can improve disease surveillance and prioritize limited resources. PMID:26042984

Maternal Characteristics Associated With Social Support in At-Risk Mothers of Premature Infants.

PubMed

White-Traut, Rosemary; Rankin, Kristin; Fabiyi, Camille; Liu, Li; Cheung, Irene; Norr, Kathleen

To identify maternal characteristics associated with social support among new mothers of premature infants who are at social-environmental risk. Cross-sectional analysis of intake interview data from a larger randomized controlled trial of a mother-premature infant developmentally based intervention. Two urban community-based hospitals. One hundred ninety-four women (50% Black, 50% Hispanic) who recently gave birth to otherwise healthy, premature (29-34 weeks gestational age) infants. Participants had at least 2 of 10 social-environmental risks (e.g., poverty). In-hospital interviews were conducted to obtain data on sociodemographic characteristics, prior mental health problems, and social support through the use of the Personal Resources Questionnaire 2000. Bivariate and multivariable linear regression analyses were performed to identify factors associated with social support. Mean Personal Resources Questionnaire 2000 scores were significantly lower for Hispanic than Black participants (92.0 vs. 96.0, respectively), those interviewed in Spanish versus English (89.8 vs. 96.1), those with low versus age-appropriate education levels (89.7 vs. 95.3), multiparous versus primiparous women (92.7 vs. 96.0), and those reporting versus not reporting histories of mental health problems (84.7 vs. 94.8). After multivariable adjustment, only younger age, Spanish language preference, multiparity, and a history of mental health problems were associated with significantly lower levels of social support (R 2  = 0.18). More programs should be made available to provide social support to at-risk mothers, especially younger mothers, and those with limited English ability, other children at home, or histories of mental health problems. Nurses should target these mothers for additional support during their premature infants' NICU stay. Copyright © 2017 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses. Published by Elsevier Inc. All rights reserved.

ON COMPUTING UPPER LIMITS TO SOURCE INTENSITIES

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

Kashyap, Vinay L.; Siemiginowska, Aneta; Van Dyk, David A.

2010-08-10

A common problem in astrophysics is determining how bright a source could be and still not be detected in an observation. Despite the simplicity with which the problem can be stated, the solution involves complicated statistical issues that require careful analysis. In contrast to the more familiar confidence bound, this concept has never been formally analyzed, leading to a great variety of often ad hoc solutions. Here we formulate and describe the problem in a self-consistent manner. Detection significance is usually defined by the acceptable proportion of false positives (background fluctuations that are claimed as detections, or Type I error),more » and we invoke the complementary concept of false negatives (real sources that go undetected, or Type II error), based on the statistical power of a test, to compute an upper limit to the detectable source intensity. To determine the minimum intensity that a source must have for it to be detected, we first define a detection threshold and then compute the probabilities of detecting sources of various intensities at the given threshold. The intensity that corresponds to the specified Type II error probability defines that minimum intensity and is identified as the upper limit. Thus, an upper limit is a characteristic of the detection procedure rather than the strength of any particular source. It should not be confused with confidence intervals or other estimates of source intensity. This is particularly important given the large number of catalogs that are being generated from increasingly sensitive surveys. We discuss, with examples, the differences between these upper limits and confidence bounds. Both measures are useful quantities that should be reported in order to extract the most science from catalogs, though they answer different statistical questions: an upper bound describes an inference range on the source intensity, while an upper limit calibrates the detection process. We provide a recipe for computing upper limits that applies to all detection algorithms.« less

Improving the Energy Market: Algorithms, Market Implications, and Transmission Switching

NASA Astrophysics Data System (ADS)

Lipka, Paula Ann

This dissertation aims to improve ISO operations through a better real-time market solution algorithm that directly considers both real and reactive power, finds a feasible Alternating Current Optimal Power Flow solution, and allows for solving transmission switching problems in an AC setting. Most of the IEEE systems do not contain any thermal limits on lines, and the ones that do are often not binding. Chapter 3 modifies the thermal limits for the IEEE systems to create new, interesting test cases. Algorithms created to better solve the power flow problem often solve the IEEE cases without line limits. However, one of the factors that makes the power flow problem hard is thermal limits on the lines. The transmission networks in practice often have transmission lines that become congested, and it is unrealistic to ignore line limits. Modifying the IEEE test cases makes it possible for other researchers to be able to test their algorithms on a setup that is closer to the actual ISO setup. This thesis also examines how to convert limits given on apparent power---as is in the case in the Polish test systems---to limits on current. The main consideration in setting line limits is temperature, which linearly relates to current. Setting limits on real or apparent power is actually a proxy for using the limits on current. Therefore, Chapter 3 shows how to convert back to the best physical representation of line limits. A sequential linearization of the current-voltage formulation of the Alternating Current Optimal Power Flow (ACOPF) problem is used to find an AC-feasible generator dispatch. In this sequential linearization, there are parameters that are set to the previous optimal solution. Additionally, to improve accuracy of the Taylor series approximations that are used, the movement of the voltage is restricted. The movement of the voltage is allowed to be very large at the first iteration and is restricted further on each subsequent iteration, with the restriction corresponding to the accuracy and AC-feasiblity of the solution. This linearization was tested on the IEEE and Polish systems, which range from 14 to 3375 buses and 20 to 4161 transmission lines. It had an accuracy of 0.5% or less for all but the 30-bus system. It also solved in linear time with CPLEX, while the non-linear version solved in O(n1.11) to O(n1.39). The sequential linearization is slower than the nonlinear formulation for smaller problems, but faster for larger problems, and its linear computational time means it would continue solving faster for larger problems. A major consideration to implementing algorithms to solve the optimal generator dispatch is ensuring that the resulting prices from the algorithm will support the market. Since the sequential linearization is linear, it is convex, its marginal values are well-defined, and there is no duality gap. The prices and settlements obtained from the sequential linearization therefore can be used to run a market. This market will include extra prices and settlements for reactive power and voltage, compared to the present-day market, which is based on real power. An advantage of this is that there is a very clear pool that can be used for reactive power/voltage support payments, while presently there is not a clear pool to take them out of. This method also reveals how valuable reactive power and voltage are at different locations, which can enable better planning of reactive resource construction. Transmission switching increases the feasible region of the generator dispatch, which means there may be a better solution than without transmission switching. Power flows on transmission lines are not directly controllable; rather, the power flows according to how it is injected and the physical characteristics of the lines. Changing the network topology changes the physical characteristics, which changes the flows. This means that sets of generator dispatch that may have previously been infeasible due to the flow exceeding line constraints may be feasible, since the flows will be different and may meet line constraints. However, transmission switching is a mixed integer problem, which may have a very slow solution time. For economic switching, we examine a series of heuristics. We examine the congestion rent heuristic in detail and then examine many other heuristics at a higher level. Post-contingency corrective switching aims to fix issues in the power network after a line or generator outage. In Chapter 7, we show that using the sequential linear program with corrective switching helps solve voltage and excessive flow issues. (Abstract shortened by UMI.).

Depression and anxiety in patients with AL amyloidosis as assessed by the SF-36 questionnaire: experience in 1226 patients.

PubMed

Shu, Janet; Lo, Stephen; Phillips, Margot; Sun, Fangui; Seldin, David C; Berenbaum, Isidore; Berk, John L; Sanchorawala, Vaishali

2016-09-01

Our study examines depression and anxiety in patients with immunoglobulin light chain (AL) amyloidosis, and determines the associations between the mental health problems and patient characteristics (age, gender, race, marital status, alcohol consumption, smoking status and cardiac involvement). Patients with AL amyloidosis who completed the 36-item Short Form General Health Survey (SF-36) during initial evaluation at a single center were studied. The SF-36 included assessments of depression, anxiety, role limitation due to emotional problems and the mental health subscale score. From 1226 patients with AL amyloidosis, 37.0% reported depression and 46.7% reported anxiety. Patients with cardiac amyloidosis reported more anxiety (odds ratio (OR) = 1.29, 95% confidence interval (CI) 1.03-1.61) and role limitation due to emotional problems (OR = 1.32, 95%CI 1.05-1.65). No significant association between cardiac involvement and depression was found (OR = 1.22, 95%CI 0.97-1.54). Men reported less anxiety (OR = 0.72, 95%CI 0.57-0.91). Patients  ≥65 years experienced greater role limitation (OR = 1.36, 95%CI 1.08-1.71). Smokers (p = 0.019) and women (p = 0.006) scored lower on mental health subscales. Many patients with AL amyloidosis suffer from depression, anxiety and functional limitations. Psychiatric assessment and treatment is important, and further research is needed to clarify the long-term effects of depression and anxiety in AL amyloidosis. This current study was registered in ClinicalTrials.gov as NCT00898235.

Interrater reliability of the Korean version of the International Spinal Cord Injury Basic Pain Data Set.

PubMed

Kim, H R; Kim, H B; Lee, B S; Ko, H Y; Shin, H I

2014-11-01

To provide a Korean translation of the International Spinal Cord Injury Basic Pain Data Set (ISCIBPDS) and evaluate the interrater reliability of the translated version. Survey of community-dwelling people with spinal cord injury (SCI) in South Korea. The initial translation was performed by two translators with an in-depth knowledge of SCI, and was then checked by another person with a similar background. A total of 115 SCI participants (87 men, 28 women; 48.4±14.1 years) were evaluated using the Korean version of the ISCIBPDS by two different raters. Intraclass correlation coefficient (ICC) or Cohen's kappa (κ) was used for analysis. All 115 participants had at least one pain problem on both surveys. Seventeen (14.8%) participants described their pain as a single pain problem to one rater while reporting the same pain as two or more different pain problems to the other rater. Twenty-two (19.1%) other participants reported their pain problems in a different order of severity on the surveys. The Korean version of the ISCIBPDS had acceptable interrater reliability, except in the 'limit activities (how much do you limit your activities in order to keep your pain from getting worse?)' item (ICC=0.318). Provision of criteria for pain separation may facilitate the consistent application of ISCIBPDS. In addition, the ISCIBPDS, which evaluated pain problems separately, reflected the multiple and complex characteristics of SCI-related pain; this was a strength of this data set.

Improved near-field characteristics of phased arrays for assessing concrete and cementitious materials

NASA Astrophysics Data System (ADS)

Wooh, Shi-Chang; Azar, Lawrence

1999-01-01

The degradation of civil infrastructure has placed a focus on effective nondestructive evaluation techniques to correctly assess the condition of existing concrete structures. Conventional high frequency ultrasonic response are severely affected by scattering and material attenuation, resulting in weak and confusing signal returns. Therefore, low frequency ultrasonic transducers, which avoid this problem of wave attenuation, are commonly used for concrete with limited capabilities. The focus of this research is to ascertain some benefits and limitations of a low frequency ultrasonic phased array transducer. In this paper, we investigate a novel low-frequency ultrasonic phased array and the results of experimental feasibility test for practical condition assessment of concrete structures are reported.

Network simulation using the simulation language for alternate modeling (SLAM 2)

NASA Technical Reports Server (NTRS)

Shen, S.; Morris, D. W.

1983-01-01

The simulation language for alternate modeling (SLAM 2) is a general purpose language that combines network, discrete event, and continuous modeling capabilities in a single language system. The efficacy of the system's network modeling is examined and discussed. Examples are given of the symbolism that is used, and an example problem and model are derived. The results are discussed in terms of the ease of programming, special features, and system limitations. The system offers many features which allow rapid model development and provides an informative standardized output. The system also has limitations which may cause undetected errors and misleading reports unless the user is aware of these programming characteristics.

Currie detection limits in gamma-ray spectroscopy.

PubMed

De Geer, Lars-Erik

2004-01-01

Currie Hypothesis testing is applied to gamma-ray spectral data, where an optimum part of the peak is used and the background is considered well known from nearby channels. With this, the risk of making Type I errors is about 100 times lower than commonly assumed. A programme, PeakMaker, produces random peaks with given characteristics on the screen and calculations are done to facilitate a full use of Poisson statistics in spectrum analyses. SHORT TECHNICAL NOTE SUMMARY: The Currie decision limit concept applied to spectral data is reinterpreted, which gives better consistency between the selected error risk and the observed error rates. A PeakMaker program is described and the few count problem is analyzed.

Kinetic theory analysis of rarefied gas flow through finite length slots

NASA Technical Reports Server (NTRS)

Raghuraman, P.

1972-01-01

An analytic study is made of the flow a rarefied monatomic gas through a two dimensional slot. The parameters of the problem are the ratios of downstream to upstream pressures, the Knudsen number at the high pressure end (based on slot half width) and the length to slot half width ratio. A moment method of solution is used by assuming a discontinuous distribution function consisting of four Maxwellians split equally in angular space. Numerical solutions are obtained for the resulting equations. The characteristics of the transition regime are portrayed. The solutions in the free molecule limit are systematically lower than the results obtained in that limit by more accurate numerical methods.

Four decades of implicit Monte Carlo

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

Wollaber, Allan B.

In 1971, Fleck and Cummings derived a system of equations to enable robust Monte Carlo simulations of time-dependent, thermal radiative transfer problems. Denoted the “Implicit Monte Carlo” (IMC) equations, their solution remains the de facto standard of high-fidelity radiative transfer simulations. Over the course of 44 years, their numerical properties have become better understood, and accuracy enhancements, novel acceleration methods, and variance reduction techniques have been suggested. In this review, we rederive the IMC equations—explicitly highlighting assumptions as they are made—and outfit the equations with a Monte Carlo interpretation. We put the IMC equations in context with other approximate formsmore » of the radiative transfer equations and present a new demonstration of their equivalence to another well-used linearization solved with deterministic transport methods for frequency-independent problems. We discuss physical and numerical limitations of the IMC equations for asymptotically small time steps, stability characteristics and the potential of maximum principle violations for large time steps, and solution behaviors in an asymptotically thick diffusive limit. We provide a new stability analysis for opacities with general monomial dependence on temperature. Here, we consider spatial accuracy limitations of the IMC equations and discussion acceleration and variance reduction techniques.« less

The concept of `work ability' from the view point of employers.

PubMed

Jansson, Inger; Björklund, Anita; Perseius, Kent-Inge; Gunnarsson, A Birgitta

2015-01-01

Since work ability is manifested in working life and ``bought'' by employers, employers perceptions of the concept are important to understand. Studies have shown that people with health problems want to take part in the labour market, but experience difficulties in gaining access. Additionally, studies have demonstrated the doubt felt by employers when they consider hiring a person with a disability. The aim was to identify and characterise employers' conceptions of work ability. The study design was qualitative with a phenomenographic approach. Six male and six female employers from various workplaces and geographical areas in Sweden were interviewed. Three domains were identified: employees' contributions to work ability, employers' contributions to work ability and circumstances with limited work ability. Work ability was regarded as a tool in production and its output, production, was the main issue. The employees' commitment and interest could bridge other shortcomings. The employers highlighted their own contributions in shaping work ability in order to fit with work circumstances. Health problems were not the only limiting issues; other circumstances, such as individual characteristics and contextual factors, could limit work ability too. Knowing the importance of commitment and interest is valuable in work rehabilitation.

Four decades of implicit Monte Carlo

DOE PAGES

Wollaber, Allan B.

2016-02-23

In 1971, Fleck and Cummings derived a system of equations to enable robust Monte Carlo simulations of time-dependent, thermal radiative transfer problems. Denoted the “Implicit Monte Carlo” (IMC) equations, their solution remains the de facto standard of high-fidelity radiative transfer simulations. Over the course of 44 years, their numerical properties have become better understood, and accuracy enhancements, novel acceleration methods, and variance reduction techniques have been suggested. In this review, we rederive the IMC equations—explicitly highlighting assumptions as they are made—and outfit the equations with a Monte Carlo interpretation. We put the IMC equations in context with other approximate formsmore » of the radiative transfer equations and present a new demonstration of their equivalence to another well-used linearization solved with deterministic transport methods for frequency-independent problems. We discuss physical and numerical limitations of the IMC equations for asymptotically small time steps, stability characteristics and the potential of maximum principle violations for large time steps, and solution behaviors in an asymptotically thick diffusive limit. We provide a new stability analysis for opacities with general monomial dependence on temperature. Here, we consider spatial accuracy limitations of the IMC equations and discussion acceleration and variance reduction techniques.« less

The limited relevance of analytical ethics to the problems of bioethics.

PubMed

Holmes, R L

1990-04-01

Philosophical ethics comprises metaethics, normative ethics and applied ethics. These have characteristically received analytic treatment by twentieth-century Anglo-American philosophy. But there has been disagreement over their interrelationship to one another and the relationship of analytical ethics to substantive morality--the making of moral judgments. I contend that the expertise philosophers have in either theoretical or applied ethics does not equip them to make sounder moral judgments on the problems of bioethics than nonphilosophers. One cannot "apply" theories like Kantianism or consequentialism to get solutions to practical moral problems unless one knows which theory is correct, and that is a metaethical question over which there is no consensus. On the other hand, to presume to be able to reach solutions through neutral analysis of problems is unavoidably to beg controversial theoretical issues in the process. Thus, while analytical ethics can play an important clarificatory role in bioethics, it can neither provide, nor substitute for, moral wisdom.

Finite-time convergent recurrent neural network with a hard-limiting activation function for constrained optimization with piecewise-linear objective functions.

PubMed

Liu, Qingshan; Wang, Jun

2011-04-01

This paper presents a one-layer recurrent neural network for solving a class of constrained nonsmooth optimization problems with piecewise-linear objective functions. The proposed neural network is guaranteed to be globally convergent in finite time to the optimal solutions under a mild condition on a derived lower bound of a single gain parameter in the model. The number of neurons in the neural network is the same as the number of decision variables of the optimization problem. Compared with existing neural networks for optimization, the proposed neural network has a couple of salient features such as finite-time convergence and a low model complexity. Specific models for two important special cases, namely, linear programming and nonsmooth optimization, are also presented. In addition, applications to the shortest path problem and constrained least absolute deviation problem are discussed with simulation results to demonstrate the effectiveness and characteristics of the proposed neural network.

Negative Emotionality and Externalizing Problems in Toddlerhood: Overreactive Parenting as a Moderator of Genetic Influences

PubMed Central

Lipscomb, Shannon T.; Leve, Leslie D.; Shaw, Daniel S.; Neiderhiser, Jenae M.; Scaramella, Laura V.; Ge, Xiaojia; Conger, Rand D.; Reid, John B.; Reiss, David

2011-01-01

The current study examined the interplay between parental overreactivity and children’s genetic backgrounds as inferred from birth parent characteristics on the development of negative emotionality during infancy, and in turn, to individual differences in externalizing problems in toddlerhood. The sample included 361 families linked through adoption (birth parents and adoptive families). Data were collected when the children were 9-, 18-, and 27-months old. Results indicated links between individual levels and changes in negative emotionality during infancy and toddlerhood to externalizing problems early in the third year of life. Findings also revealed an interaction between birth mother negative affect and adoptive mother overreactive parenting on children’s negative emotionality. This genotype × environment interaction predicted externalizing problems indirectly through its association with negative emotionality and revealed stronger effects of genetic risk for children with less overreactive parenting from their mothers. Limitations of this study and directions for future research are discussed. PMID:22293002

Characteristics of Problem Posing of Grade 9 Students on Geometric Tasks

ERIC Educational Resources Information Center

Chua, Puay Huat; Wong, Khoon Yoong

2012-01-01

This is an exploratory study into the individual problem-posing characteristics of 480 Grade 9 Singapore students who were novice problem posers working on two geometric tasks. The students were asked to pose a problem for their friends to solve. Analyses of solvable posed problems were based on the problem type, problem information, solution type…

Congested Aggregation via Newtonian Interaction

NASA Astrophysics Data System (ADS)

Craig, Katy; Kim, Inwon; Yao, Yao

2018-01-01

We consider a congested aggregation model that describes the evolution of a density through the competing effects of nonlocal Newtonian attraction and a hard height constraint. This provides a counterpoint to existing literature on repulsive-attractive nonlocal interaction models, where the repulsive effects instead arise from an interaction kernel or the addition of diffusion. We formulate our model as the Wasserstein gradient flow of an interaction energy, with a penalization to enforce the constraint on the height of the density. From this perspective, the problem can be seen as a singular limit of the Keller-Segel equation with degenerate diffusion. Two key properties distinguish our problem from previous work on height constrained equations: nonconvexity of the interaction kernel (which places the model outside the scope of classical gradient flow theory) and nonlocal dependence of the velocity field on the density (which causes the problem to lack a comparison principle). To overcome these obstacles, we combine recent results on gradient flows of nonconvex energies with viscosity solution theory. We characterize the dynamics of patch solutions in terms of a Hele-Shaw type free boundary problem and, using this characterization, show that in two dimensions patch solutions converge to a characteristic function of a disk in the long-time limit, with an explicit rate on the decay of the energy. We believe that a key contribution of the present work is our blended approach, combining energy methods with viscosity solution theory.

Resource-constrained scheduling with hard due windows and rejection penalties

NASA Astrophysics Data System (ADS)

Garcia, Christopher

2016-09-01

This work studies a scheduling problem where each job must be either accepted and scheduled to complete within its specified due window, or rejected altogether. Each job has a certain processing time and contributes a certain profit if accepted or penalty cost if rejected. There is a set of renewable resources, and no resource limit can be exceeded at any time. Each job requires a certain amount of each resource when processed, and the objective is to maximize total profit. A mixed-integer programming formulation and three approximation algorithms are presented: a priority rule heuristic, an algorithm based on the metaheuristic for randomized priority search and an evolutionary algorithm. Computational experiments comparing these four solution methods were performed on a set of generated benchmark problems covering a wide range of problem characteristics. The evolutionary algorithm outperformed the other methods in most cases, often significantly, and never significantly underperformed any method.

Remote sensing image stitch using modified structure deformation

NASA Astrophysics Data System (ADS)

Pan, Ke-cheng; Chen, Jin-wei; Chen, Yueting; Feng, Huajun

2012-10-01

To stitch remote sensing images seamlessly without producing visual artifact which is caused by severe intensity discrepancy and structure misalignment, we modify the original structure deformation based stitching algorithm which have two main problems: Firstly, using Poisson equation to propagate deformation vectors leads to the change of the topological relationship between the key points and their surrounding pixels, which may bring in wrong image characteristics. Secondly, the diffusion area of the sparse matrix is too limited to rectify the global intensity discrepancy. To solve the first problem, we adopt Spring-Mass model and bring in external force to keep the topological relationship between key points and their surrounding pixels. We also apply tensor voting algorithm to achieve the global intensity corresponding curve of the two images to solve the second problem. Both simulated and experimental results show that our algorithm is faster and can reach better result than the original algorithm.

The Effects of Warhead-Induced Damage on the Aeroelastic Characteristics of Lifting Surfaces. Volume I. Aeroelastic Effects.

DTIC Science & Technology

1980-07-01

Arnold. Some further insight into the problem is obtained here, however, when it is demonstrated that highly optimized structural designs may...aircraft of this type are normally designed to withstand loads up to 1.5 times the maximum limit load (load factor 8.0 to 8.67), the structure should...on the wing, for example, give rise to concentrated drag and chordwise loadings as does the recoil from firing wing mounted gun systems . The drag on

Measuring, Estimating, and Deciding under Uncertainty.

PubMed

Michel, Rolf

2016-03-01

The problem of uncertainty as a general consequence of incomplete information and the approach to quantify uncertainty in metrology is addressed. Then, this paper discusses some of the controversial aspects of the statistical foundation of the concepts of uncertainty in measurements. The basics of the ISO Guide to the Expression of Uncertainty in Measurement as well as of characteristic limits according to ISO 11929 are described and the needs for a revision of the latter standard are explained. Copyright © 2015 Elsevier Ltd. All rights reserved.

Separation Method for Oxygen Mass Transport Coefficient in Two Phase Porous Air Electrodes - Transport in Gas and Solid Polymer or Liquid Electrolyte Phases

DTIC Science & Technology

2013-08-06

of the problem studied Proton exchange membrane fuel cells ( PEMFCs ) are the most promising candidate systems for alternative electricity...characteristic. The limiting current can be used as a tool to study mass transport phenomena in PEMFC because it can provide experimental data for the...coefficient for PEMFCs under in situ conditions based on the galvanostatic discharge of a cell with an interrupted reactant supply. The results indicated

Damping seals for turbomachinery

NASA Technical Reports Server (NTRS)

Vonpragenau, G. L.

1985-01-01

Rotor whirl stabilization of high performance turbomachinery which operates at supercritical speed is discussed. Basic whirl driving forces are reviewed. Stabilization and criteria are discussed. Damping seals are offered as a solution to whirl and high vibration problems. Concept, advantages, retrofitting, and limits of damping seals are explained. Dynamic and leakage properties are shown to require a rough stator surface for stability and efficiency. Typical seal characteristics are given for the case of the high pressure oxidizer turbopump of the Space Shuttle. Ways of implementation and bearing load effects are discussed.

Investigation of the reactions of skin panels in relation to duration of acoustical loading

NASA Technical Reports Server (NTRS)

Kvitka, V. Y.; Kernes, G. I.

1973-01-01

Certain characteristics of the reactions of typical skin panels of a passenger aircraft to acoustical loading are being investigated, for development of an objective method of diagnostics for skin condition, under the operations and maintenance sections of civil aviation. There are a number of difficulties connected with the solution of this problem. The reactions of skin panels exposed to the noises of the exhaust jets are dependent on the aircraft operating conditions, the geometric parameters and limiting conditions of the panels.

Unique Results and Lessons Learned from the TSS Missions

NASA Technical Reports Server (NTRS)

Stone, Nobie H.

2016-01-01

In 1924, Irvin Langmuir and H. M. Mott-Smith published a theoretical model for the complex plasma sheath phenomenon in which they identified some very special cases which greatly simplified the sheath and allowed a closed solution to the problem. The most widely used application is for an electrostatic, or "Langmuir," probe in laboratory plasma. Although the Langmuir probe is physically simple (a biased wire) the theory describing its functional behavior and its current-voltage characteristic is extremely complex and, accordingly, a number of assumptions and approximations are used in the LMS model. These simplifications, correspondingly, place limits on the model's range of application. Adapting the LMS model to real-life conditions is the subject of numerous papers and dissertations. The Orbit-Motion Limited (OML) model that is widely used today is one of these adaptions that is a convenient means of calculating sheath effects. The OML equation for electron current collection by a positively biased body is simply: I is approximately equal to A x j(sub eo) x 2/v??(phi)(exp ½) where A is the area of the body and phi is the electric potential on the body with respect to the plasma. Since the Langmuir probe is a simple biased wire immersed in plasma, it is particularly tempting to use the OML equation in calculating the characteristics of the long, highly biased wires of an Electric Sail in the solar wind plasma. However, in order to arrive at the OML equation, a number of additional simplifying assumptions and approximations (beyond those made by Langmuir-Mott-Smith) are necessary. The OML equation is a good approximation when all conditions are met, but it would appear that the Electric Sail problem lies outside of the limits of applicability.

Methods of equipment choice in shotcreting

NASA Astrophysics Data System (ADS)

Sharapov, R. R.; Yadykina, V. V.; Stepanov, M. A.; Kitukov, B. A.

2018-03-01

Shotcrete is widely used in architecture, hydraulic engineering structures, finishing works in tunnels, arc covers and ceilings. The problem of the equipment choice in shotcreting is very important. The main issues influencing the equipment choice are quality improvement and intensification of shotcreting. Main parameters and rational limits of technological characteristic of machines used in solving different problems in shotcreting are described. It is suggested to take into account peculiarities of shotcrete mixing processes and peculiarities of applying these mixtures with compressed air kinetic energy. The described method suggests choosing a mixer with the account of energy capacity, Reynolds number and rotational frequency of the mixing drum. The suggested choice procedure of the equipment nomenclature allows decreasing exploitation costs, increasing the quality of shotcrete and shotcreting in general.

The culture of affluence: psychological costs of material wealth.

PubMed

Luthar, Suniya S

2003-01-01

Children of affluence are generally presumed to be at low risk. However, recent studies have suggested problems in several domains--notably, substance use, anxiety, and depression--and 2 sets of potential causes: pressures to achieve and isolation from parents. Recognizing the limited awareness of these issues, the objectives in this paper are to collate evidence on the nature of problems among the wealthy and their likely causes. The first half of the paper is focused on disturbances among affluent children and the second half is focused on characteristics of their families and neighborhoods. Widespread negative sentiments toward the rich are then discussed, and the paper concludes with suggestions for future work with families at the upper end of the socioeconomic spectrum.

Hydrology team

NASA Technical Reports Server (NTRS)

Ragan, R.

1982-01-01

General problems faced by hydrologists when using historical records, real time data, statistical analysis, and system simulation in providing quantitative information on the temporal and spatial distribution of water are related to the limitations of these data. Major problem areas requiring multispectral imaging-based research to improve hydrology models involve: evapotranspiration rates and soil moisture dynamics for large areas; the three dimensional characteristics of bodies of water; flooding in wetlands; snow water equivalents; runoff and sediment yield from ungaged watersheds; storm rainfall; fluorescence and polarization of water and its contained substances; discriminating between sediment and chlorophyll in water; role of barrier island dynamics in coastal zone processes; the relationship between remotely measured surface roughness and hydraulic roughness of land surfaces and stream networks; and modeling the runoff process.

The Culture of Affluence: Psychological Costs of Material Wealth

PubMed Central

Luthar, Suniya S.

2007-01-01

Children of affluence are generally presumed to be at low risk. However, recent studies have suggested problems in several domains—notably, substance use, anxiety, and depression—and 2 sets of potential causes: pressures to achieve and isolation from parents. Recognizing the limited awareness of these issues, the objectives in this paper are to collate evidence on the nature of problems among the wealthy and their likely causes. The first half of the paper is focused on disturbances among affluent children and the second half is focused on characteristics of their families and neighborhoods. Widespread negative sentiments toward the rich are then discussed, and the paper concludes with suggestions for future work with families at the upper end of the socioeconomic spectrum. PMID:14669883

Ship dynamics for maritime ISAR imaging.

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

Doerry, Armin Walter

2008-02-01

Demand is increasing for imaging ships at sea. Conventional SAR fails because the ships are usually in motion, both with a forward velocity, and other linear and angular motions that accompany sea travel. Because the target itself is moving, this becomes an Inverse- SAR, or ISAR problem. Developing useful ISAR techniques and algorithms is considerably aided by first understanding the nature and characteristics of ship motion. Consequently, a brief study of some principles of naval architecture sheds useful light on this problem. We attempt to do so here. Ship motions are analyzed for their impact on range-Doppler imaging using Inversemore » Synthetic Aperture Radar (ISAR). A framework for analysis is developed, and limitations of simple ISAR systems are discussed.« less

Park system concept for environmental sustainabilityin urban spatial development

NASA Astrophysics Data System (ADS)

Uniaty, Q.

2018-01-01

Urban Park System is an integrated concept between nature system and urban life. The problems caused by urban population activity resulted in the need to increase the balance between two systems. Establishment of urban park system is a response to the need for resilience of urban space structures. As an ideal requirement it needs to be built integration between the ecological, social, economic, aesthetic aspects of urban landscape architecture. The methodology was developed based on an approach to issues affecting the conditions due to urban issues and its relation to the development efforts of urban park system; Observation of Jakarta problem was obtained based on published studies and data, literature, characteristic and potential analyzes, local physical, from limited field observations. Both are simple methods aimed to describe the nature of a condition as well as form characteristics of problems in controlling the development of region, to examine the causes and symptoms. This method try to assess an object study compared between the conditions before and after. The benefits of urban park system development will not only improve the urban environment, but the value of urban pride, identity and control urban growth in line with efforts to improve the balance between conservation and development. Integrated urban park system will enhance the multifunctional role, connectivity, habitability, durability, identity and investment.

Are You Your Friends' Friend? Poor Perception of Friendship Ties Limits the Ability to Promote Behavioral Change.

PubMed

Almaatouq, Abdullah; Radaelli, Laura; Pentland, Alex; Shmueli, Erez

2016-01-01

Persuasion is at the core of norm creation, emergence of collective action, and solutions to 'tragedy of the commons' problems. In this paper, we show that the directionality of friendship ties affect the extent to which individuals can influence the behavior of each other. Moreover, we find that people are typically poor at perceiving the directionality of their friendship ties and that this can significantly limit their ability to engage in cooperative arrangements. This could lead to failures in establishing compatible norms, acting together, finding compromise solutions, and persuading others to act. We then suggest strategies to overcome this limitation by using two topological characteristics of the perceived friendship network. The findings of this paper have significant consequences for designing interventions that seek to harness social influence for collective action.

Are You Your Friends’ Friend? Poor Perception of Friendship Ties Limits the Ability to Promote Behavioral Change

PubMed Central

Almaatouq, Abdullah; Radaelli, Laura; Pentland, Alex; Shmueli, Erez

2016-01-01

Persuasion is at the core of norm creation, emergence of collective action, and solutions to ‘tragedy of the commons’ problems. In this paper, we show that the directionality of friendship ties affect the extent to which individuals can influence the behavior of each other. Moreover, we find that people are typically poor at perceiving the directionality of their friendship ties and that this can significantly limit their ability to engage in cooperative arrangements. This could lead to failures in establishing compatible norms, acting together, finding compromise solutions, and persuading others to act. We then suggest strategies to overcome this limitation by using two topological characteristics of the perceived friendship network. The findings of this paper have significant consequences for designing interventions that seek to harness social influence for collective action. PMID:27002530

Fines classification based on sensitivity to pore-fluid chemistry

USGS Publications Warehouse

Jang, Junbong; Santamarina, J. Carlos

2016-01-01

The 75-μm particle size is used to discriminate between fine and coarse grains. Further analysis of fine grains is typically based on the plasticity chart. Whereas pore-fluid-chemistry-dependent soil response is a salient and distinguishing characteristic of fine grains, pore-fluid chemistry is not addressed in current classification systems. Liquid limits obtained with electrically contrasting pore fluids (deionized water, 2-M NaCl brine, and kerosene) are combined to define the soil “electrical sensitivity.” Liquid limit and electrical sensitivity can be effectively used to classify fine grains according to their fluid-soil response into no-, low-, intermediate-, or high-plasticity fine grains of low, intermediate, or high electrical sensitivity. The proposed methodology benefits from the accumulated experience with liquid limit in the field and addresses the needs of a broader range of geotechnical engineering problems.

Traction behavior of two traction lubricants

NASA Technical Reports Server (NTRS)

Loewenthal, S. H.; Rohn, D. A.

1983-01-01

In the analysis of rolling-sliding concentrated contacts, such as gears, bearings and traction drives, the traction characteristics of the lubricant are of prime importance. The elastic shear modulus and limiting shear stress properties of the lubricant dictate the traction/slip characteristics and power loss associated with an EHD contact undergoing slip and/or spin. These properties can be deducted directly from the initial slope m and maximum traction coefficient micron of an experimental traction curve. In this investigation, correlation equations are presented to predict m and micron for two modern traction fluids based on the regression analysis of 334 separate traction disk machine experiments. The effects of contact pressure, temperature, surface velocity, ellipticity ratio are examined. Problems in deducing lubricant shear moduli from disk machine tests are discussed.

The intergenerational transmission of at-risk/problem gambling: The moderating role of parenting practices.

PubMed

Dowling, Nicki A; Shandley, Kerrie A; Oldenhof, Erin; Affleck, Julia M; Youssef, George J; Frydenberg, Erica; Thomas, Shane A; Jackson, Alun C

2017-10-01

Although parenting practices are articulated as underlying mechanisms or protective factors in several theoretical models, their role in the intergenerational transmission of gambling problems has received limited research attention. This study therefore examined the degree to which parenting practices (positive parenting, parental involvement, and inconsistent discipline) moderated the intergenerational transmission of paternal and maternal problem gambling. Students aged 12-18 years (N = 612) recruited from 17 Australian secondary schools completed a survey measuring parental problem gambling, problem gambling severity, and parenting practices. Participants endorsing paternal problem gambling (23.3%) were 4.3 times more likely to be classified as at-risk/problem gamblers than their peers (5.4%). Participants endorsing maternal problem gambling (6.9%) were no more likely than their peers (4.0%) to be classified as at-risk/problem gamblers. Paternal problem gambling was a significant predictor of offspring at-risk/problem gambling after controlling for maternal problem gambling and participant demographic characteristics. The relationship between maternal problem gambling and offspring at-risk/problem gambling was buffered by parental involvement. Paternal problem gambling may be important in the development of adolescent at-risk/problem gambling behaviours and higher levels of parental involvement buffers the influence of maternal problem gambling in the development of offspring gambling problems. Further research is therefore required to identify factors that attenuate the seemingly greater risk of transmission associated with paternal gambling problems. Parental involvement is a potential candidate for prevention and intervention efforts designed to reduce the intergenerational transmission of gambling problems. (Am J Addict 2017;26:707-712). © 2017 American Academy of Addiction Psychiatry.

Plastometry for the Self-Compacting Concrete Mixes

NASA Astrophysics Data System (ADS)

Lapsa, V. Ā.; Krasnikovs, A.; Lusis, V.; Lukasenoks, A.

2015-11-01

Operative determination of consistence of self-compacting concrete mixes at plant or in construction conditions is an important problem in building practice. The Abram's cone, the Vebe's device, the U-box siphon, L-box or funnel tests are used in solving this problem. However, these field methods are targeted at determination of some indirect parameters of such very complicated paste-like material like concrete mix. They are not physical characteristics suitable for the rheological calculations of the coherence between the stress and strains, flow characteristics and the reaction of the concrete mix in different technological processes. A conical plastometer having higher precision and less sensitive to the inaccuracy of the tests in construction condition has been elaborated at the Concrete Mechanics Laboratory of RTU. In addition, a new method was elaborated for the calculation of plasticity limit τ0 taking into account the buoyancy force of the liquid or non-liquid concrete mix. In the present investigation rheological test of the concrete mix by use the plastometer and the method mentioned earlier was conducted for different self-compacting and not self-compacting concrete mixes.

The implementation and operation of a variable-response electronic throttle control system for a TF-104G aircraft

NASA Technical Reports Server (NTRS)

Neal, Bradford; Sengupta, Upal

1989-01-01

During some flight programs, researchers have encountered problems in the throttle response characteristics of high-performance aircraft. To study and to help solve these problems, the National Aeronautics and Space Administration Ames Research Center's Dryden Flight Research Facility (Ames-Dryden) conducted a study using a TF-104G airplane modified with a variable-response electronic throttle control system. Ames-Dryden investigated the effects of different variables on engine response and handling qualities. The system provided transport delay, lead and lag filters, second-order lags, command rate and position limits, and variable gain between the pilot's throttle command and the engine fuel controller. These variables could be tested individually or in combination. Ten research flights were flown to gather data on engine response and to obtain pilot ratings of the various system configurations. The results should provide design criteria for engine-response characteristics. The variable-response throttle components and how they were installed in the TF-104G aircraft are described. How the variable-response throttle was used in flight and some of the results of using this system are discussed.

Demonstration of decomposition and optimization in the design of experimental space systems

NASA Technical Reports Server (NTRS)

Padula, Sharon; Sandridge, Chris A.; Haftka, Raphael T.; Walsh, Joanne L.

1989-01-01

Effective design strategies for a class of systems which may be termed Experimental Space Systems (ESS) are needed. These systems, which include large space antenna and observatories, space platforms, earth satellites and deep space explorers, have special characteristics which make them particularly difficult to design. It is argued here that these same characteristics encourage the use of advanced computer-aided optimization and planning techniques. The broad goal of this research is to develop optimization strategies for the design of ESS. These strategics would account for the possibly conflicting requirements of mission life, safety, scientific payoffs, initial system cost, launch limitations and maintenance costs. The strategies must also preserve the coupling between disciplines or between subsystems. Here, the specific purpose is to describe a computer-aided planning and scheduling technique. This technique provides the designer with a way to map the flow of data between multidisciplinary analyses. The technique is important because it enables the designer to decompose the system design problem into a number of smaller subproblems. The planning and scheduling technique is demonstrated by its application to a specific preliminary design problem.

Is Insight Always the Same? A Protocol Analysis of Insight in Compound Remote Associate Problems

ERIC Educational Resources Information Center

Cranford, Edward A.; Moss, Jarrod

2012-01-01

Compound Remote Associate (CRA) problems have been used to investigate insight problem solving using both behavioral and neuroimaging techniques. However, it is unclear to what extent CRA problems exhibit characteristics of insight such as impasses and restructuring. CRA problem-solving characteristics were examined in a study in which…

Trail resource impacts and an examination of alternative assessment techniques

USGS Publications Warehouse

Marion, J.L.; Leung, Y.-F.

2001-01-01

Trails are a primary recreation resource facility on which recreation activities are performed. They provide safe access to non-roaded areas, support recreational opportunities such as hiking, biking, and wildlife observation, and protect natural resources by concentrating visitor traffic on resistant treads. However, increasing recreational use, coupled with poorly designed and/or maintained trails, has led to a variety of resource impacts. Trail managers require objective information on trails and their conditions to monitor trends, direct trail maintenance efforts, and evaluate the need for visitor management and resource protection actions. This paper reviews trail impacts and different types of trail assessments, including inventory, maintenance, and condition assessment approaches. Two assessment methods, point sampling and problem assessment, are compared empirically from separate assessments of a 15-mile segment of the Appalachian Trail in Great Smoky Mountains National Park. Results indicate that point sampling and problem assessment methods yield distinctly different types of quantitative information. The point sampling method provides more accurate and precise measures of trail characteristics that are continuous or frequent (e.g., tread width or exposed soil). The problem assessment method is a preferred approach for monitoring trail characteristics that can be easily predefined or are infrequent (e.g., excessive width or secondary treads), particularly when information on the location of specific trail impact problems is needed. The advantages and limitations of these two assessment methods are examined in relation to various management and research information needs. The choice and utility of these assessment methods are also discussed.

Thermal-treated soil for mercury removal: Soil and phytotoxicity tests

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

Roh, Y.; Edwards, N.T.; Lee, S.Y.

Mercury (Hg) contamination of soils and sediments is one of many environmental problems at the Oak Ridge Reservation, Oak Ridge, TN. Mercury-contaminated soil from the Lower East Fork Poplar Creek (LEFPC) at the Oak Ridge Reservation was treated thermally to reduce Hg concentration to a below target level (20 mg kg{sup {minus}1}) as a pilot scale thermal treatment demonstration. As a part of performance evaluation, the soil characteristics and plant growth response of the untreated and treated soil were examined. The soil treated at 350 C retained most of its original soil properties, but the soil treated at 600 Cmore » exhibited considerable changes in mineralogical composition and physicochemical characteristics. Growth and physiological response of the three plant species radish (Raphanus sativus L.), fescue (Festuca arundinacea Schreb.), and oat (Avena sativa L.) indicated adverse effects of the thermal treatment. The addition of N fertilizer had beneficial effects in the 350 C treated soil, but had little beneficial effect in the 600 C treated soil. Some changes of soil characteristics induced by thermal treatment cannot be avoided. Soil characteristics and phytotoxicity test results strongly suggest that changes occurring following the 350 C treatment do not limit the use of the treated soil to refill the excavated site for full-scale remediation. The only problem with the 350 C treatment is that small amounts of Hg compounds (<15 mg kg{sup {minus}1}) remain in the soil and a processing cost of $45/Mg.« less

Characteristics of older adult problem gamblers calling a gambling helpline.

PubMed

Potenza, Marc N; Steinberg, Marvin A; Wu, Ran; Rounsaville, Bruce J; O'malley, Stephanie S

2006-06-01

Few investigations have characterized groups of older adults with gambling problems, and published reports are currently limited by small samples of older adult problem gamblers. Gambling helplines represent a widespread mechanism for assisting problem gamblers to move into treatment settings. Given data from older adult problem gamblers in treatment, we hypothesized that older as compared with younger adult problem gamblers calling a gambling helpline would be less likely to report gambling-related problems. Logistic regression analyses were performed on data obtained from January 1, 2000 to December 31, 2001, inclusive, from callers with gambling problems (N = 1,084) contacting the Connecticut Council on Problem Gambling Helpline. Of the 1,018 phone calls used in the logistic regression analyses, 168 (16.5%) were from older adults and 850 (83.5%) from younger adults. Age-related differences were observed in demographic features, types and patterns of gambling reported as problematic, gambling-related problems and psychiatric symptoms, substance use problems, patterns of indebtedness, and family histories of addictive disorders. Older as compared with younger adult problem gamblers were more likely to report having lower incomes, longer durations of gambling, fewer types of problematic gambling, and problems with casino slot machine gambling and less likely to report gambling-related anxiety, family problems, illegal behaviors and arrests, drug problems, indebtedness to bookies or acquaintances, family histories of drug abuse, and problems with casino table gambling. Older as compared with younger adult problem gamblers calling a gambling helpline differ on many clinically relevant features. The findings suggest the need for improved and unique prevention and treatment strategies for older adults with gambling problems.

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

Campbell, Philip LaRoche

At the end of his life, Stephen Jay Kline, longtime professor of mechanical engineering at Stanford University, completed a book on how to address complex systems. The title of the book is 'Conceptual Foundations of Multi-Disciplinary Thinking' (1995), but the topic of the book is systems. Kline first establishes certain limits that are characteristic of our conscious minds. Kline then establishes a complexity measure for systems and uses that complexity measure to develop a hierarchy of systems. Kline then argues that our minds, due to their characteristic limitations, are unable to model the complex systems in that hierarchy. Computers aremore » of no help to us here. Our attempts at modeling these complex systems are based on the way we successfully model some simple systems, in particular, 'inert, naturally-occurring' objects and processes, such as what is the focus of physics. But complex systems overwhelm such attempts. As a result, the best we can do in working with these complex systems is to use a heuristic, what Kline calls the 'Guideline for Complex Systems.' Kline documents the problems that have developed due to 'oversimple' system models and from the inappropriate application of a system model from one domain to another. One prominent such problem is the Procrustean attempt to make the disciplines that deal with complex systems be 'physics-like.' Physics deals with simple systems, not complex ones, using Kline's complexity measure. The models that physics has developed are inappropriate for complex systems. Kline documents a number of the wasteful and dangerous fallacies of this type.« less

Usability and clinical efficacy of diabetes mobile applications for adults with type 2 diabetes: A systematic review.

PubMed

Fu, Helen; McMahon, Siobhan K; Gross, Cynthia R; Adam, Terrence J; Wyman, Jean F

2017-09-01

To assess the usability and clinical effectiveness of diabetes mobile applications (diabetes apps) developed for adults with type 2 diabetes. A systematic review of the usability and effectiveness of diabetes apps was conducted. Searches were performed using MEDLINE, EMBASE, COMPENDEX, and IEEE XPLORE for articles published from January 1, 2011, to January 17, 2017. Search terms included: diabetes, mobile apps, and mobile health (mHealth). The search yielded 723 abstracts of which seven usability studies and ten clinical effectiveness studies met the inclusion criteria from 20 publications. Usability, as measured by satisfaction ratings from experts and patients, ranged from 38% to 80%. Usability problem ratings ranged from moderate to catastrophic. Top usability problems are multi-steps task, limited functionality and interaction, and difficult system navigation. Clinical effectiveness, measured by reductions in HbA1c, ranged from 0.15% to 1.9%. Despite meager satisfaction ratings and major usability problems, there is some limited evidence supporting the effectiveness of diabetes apps to improve glycemic control for adults with type 2 diabetes. Findings strongly suggest that efforts to improve user satisfaction, incorporate established principles of health behavior change, and match apps to user characteristics will increase the therapeutic impact of diabetes apps. Copyright © 2017 Elsevier B.V. All rights reserved.

New PDC bit design reduces vibrational problems

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

Mensa-Wilmot, G.; Alexander, W.L.

1995-05-22

A new polycrystalline diamond compact (PDC) bit design combines cutter layout, load balancing, unsymmetrical blades and gauge pads, and spiraled blades to reduce problematic vibrations without limiting drilling efficiency. Stabilization improves drilling efficiency and also improves dull characteristics for PDC bits. Some PDC bit designs mitigate one vibrational mode (such as bit whirl) through drilling parameter manipulation yet cause or excite another vibrational mode (such as slip-stick). An alternative vibration-reducing concept which places no limitations on the operational environment of a PDC bit has been developed to ensure optimization of the bit`s available mechanical energy. The paper discusses bit stabilization,more » vibration reduction, vibration prevention, cutter arrangement, load balancing, blade layout, spiraled blades, and bit design.« less

Optimization of multimagnetometer systems on a spacecraft

NASA Technical Reports Server (NTRS)

Neubauer, F. M.

1975-01-01

The problem of optimizing the position of magnetometers along a boom of given length to yield a minimized total error is investigated. The discussion is limited to at most four magnetometers, which seems to be a practical limit due to weight, power, and financial considerations. The outlined error analysis is applied to some illustrative cases. The optimal magnetometer locations, for which the total error is minimum, are computed for given boom length, instrument errors, and very conservative magnetic field models characteristic for spacecraft with only a restricted or ineffective magnetic cleanliness program. It is shown that the error contribution by the magnetometer inaccuracy is increased as the number of magnetometers is increased, whereas the spacecraft field uncertainty is diminished by an appreciably larger amount.

Characteristics of the personal and environmental components of person-environment fit in very old age: a comparison between people with self-reported Parkinson's disease and matched controls.

PubMed

Slaug, Björn; Nilsson, Maria H; Iwarsson, Susanne

2013-12-01

To investigate differences and similarities in person-environment (P-E) fit problems between very old people with self-reported Parkinson's disease (PD) and matched controls. Data collected for the cross-national ENABLE-AGE Survey Study were used to identify people with self-reported PD (n = 20), and to select three matched controls per individual (n = 60). The matching criteria were age (mean = 82 years), sex, country, and type of housing. The data analysis targeted P-E fit (i.e. accessibility) problems, including studying the personal and environmental components separately. The personal component was analyzed in terms of functional limitations, and the environmental component in terms of physical environmental barriers. In comparison to the matched controls, the participants with PD had more functional limitations, used more mobility devices and were subjected to more P-E fit problems, though the number of environmental barriers did not differ from the controls. In the PD sample, P-E fit problems were significantly stronger associated with poor balance and incoordination, and the environmental barriers that generated the most severe P-E fit problems were more often located to the exterior surroundings of the housing compared to the controls. The novel contribution of this explorative study is the demonstration of the type of knowledge that can be generated by unfolding and comparing the composition of P-E fit (accessibility) problems among people with self-reported PD as compared with matched controls. The knowledge thereby generated can be used to develop more targeted rehabilitation approaches, efficient housing adaptation services and societal planning for people with neurodegenerative disorders.

Quantification of susceptibility change at high-concentrated SPIO-labeled target by characteristic phase gradient recognition.

PubMed

Zhu, Haitao; Nie, Binbin; Liu, Hua; Guo, Hua; Demachi, Kazuyuki; Sekino, Masaki; Shan, Baoci

2016-05-01

Phase map cross-correlation detection and quantification may produce highlighted signal at superparamagnetic iron oxide nanoparticles, and distinguish them from other hypointensities. The method may quantify susceptibility change by performing least squares analysis between a theoretically generated magnetic field template and an experimentally scanned phase image. Because characteristic phase recognition requires the removal of phase wrap and phase background, additional steps of phase unwrapping and filtering may increase the chance of computing error and enlarge the inconsistence among algorithms. To solve problem, phase gradient cross-correlation and quantification method is developed by recognizing characteristic phase gradient pattern instead of phase image because phase gradient operation inherently includes unwrapping and filtering functions. However, few studies have mentioned the detectable limit of currently used phase gradient calculation algorithms. The limit may lead to an underestimation of large magnetic susceptibility change caused by high-concentrated iron accumulation. In this study, mathematical derivation points out the value of maximum detectable phase gradient calculated by differential chain algorithm in both spatial and Fourier domain. To break through the limit, a modified quantification method is proposed by using unwrapped forward differentiation for phase gradient generation. The method enlarges the detectable range of phase gradient measurement and avoids the underestimation of magnetic susceptibility. Simulation and phantom experiments were used to quantitatively compare different methods. In vivo application performs MRI scanning on nude mice implanted by iron-labeled human cancer cells. Results validate the limit of detectable phase gradient and the consequent susceptibility underestimation. Results also demonstrate the advantage of unwrapped forward differentiation compared with differential chain algorithms for susceptibility quantification at high-concentrated iron accumulation. Copyright © 2015 Elsevier Inc. All rights reserved.

Prevalence of foot problems in people with inflammatory arthritis in Singapore.

PubMed

Carter, K; Lahiri, M; Cheung, P P; Santosa, A; Rome, K

2016-01-01

Foot problems are highly prevalent in people with inflammatory arthritis reported from studies in the UK, Europe and New Zealand, but there is limited evidence from Southeast Asia. The study aim was to evaluate the prevalence of foot problems in people with inflammatory arthritis in Singapore. People with inflammatory arthritis were recruited from the rheumatology outpatient clinic of a tertiary hospital in Singapore. Disease and clinical characteristics included age, sex, disease duration, current blood tests and medications. The Leeds Foot Impact Scale was used to evaluate foot impairment/disability and the Modified Health Assessment Questionnaire was used to assess global function. We recruited 101 people with inflammatory arthritis, of which 50 % were female. The majority of participants were Chinese (70 %). The mean (SD) age was 52 (15) years, and the mean (SD) disease duration was 9.3 (0.3) years. The most commonly reported inflammatory arthritic conditions were rheumatoid arthritis (46), gout (31) and spondyloarthritis (15 %). The mean (SD) of the total Leeds Foot Impact Scale was 17 (13) indicating moderate to severe levels of foot impairment and activity limitation. Over 80 of participants reported foot pain during the course of their condition, and 48 % reported current foot pain. Despite the high prevalence of foot pain, only 21 participants (21 %) had been referred to a podiatrist. This is the first study to investigate the prevalence of foot problems in people with inflammatory arthritis from Singapore. The majority of the participants reported foot problems, but had not been referred to a podiatry service.

Behavioral correlation with television watching and videogame playing among children in the United Arab Emirates.

PubMed

Yousef, Said; Eapen, Valsamma; Zoubeidi, Taoufik; Mabrouk, Abdelazim

2014-08-01

Television viewing and videogame use (TV/VG) appear to be associated with some childhood behavioral problems. There are no studies addressing this problem in the United Arab Emirates. One hundred ninety-seven school children (mean age, 8.7 ± 2.1 years) were assessed. Child Behavior Checklist (CBCL) subscale scores and socio-demographic characteristics were compared between children who were involved with TV/VG more than 2 hours/day and those involved less than 2 hours/day (the recommended upper limit by The American Academy of Pediatrics). Thirty-seven percent of children who were involved with TV/VG time of more than 2 hours/day scored significantly higher on CBCL syndrome scales of withdrawn, social problems, attention problems, delinquent behavior, aggressive behavior, internalizing problems, externalizing problems and the CBCL total scores compared with their counterparts. Moreover, these children were younger in birth order and had fewer siblings. After controlling for these confounders using logistic regression, we found that TV/VG time more than 2 hours/day was positively associated with withdrawn (p = 0.008), attention problem (p = 0.037), externalizing problems (p = 0.007), and CBCL total (p = 0.014). Involvement with TV/VG for more than 2 hours/day is associated with more childhood behavioral problems. Counteracting negative effects of the over-involvement with TV/VG in children requires increased parental awareness.

Types and Characteristics of Childhood Sexual Abuse: How Do They Matter in HIV Sexual Risk Behaviors Among Women in Methadone Treatment in New York City?

PubMed

Engstrom, Malitta; Winham, Katherine; Gilbert, Louisa

2016-01-01

Childhood sexual abuse (CSA) is often considered an important distal factor in HIV sexual risk behaviors; however, there are limited and mixed findings regarding this relationship among women experiencing substance use problems. In addition, research with this population of women has yet to examine differences in observed CSA-HIV sexual risk behaviors relationships by CSA type and characteristics. This study examines relationships between CSA coding, type, and characteristics and HIV sexual risk behaviors with main intimate partners among a random sample of 390 women in methadone treatment in New York City who completed individual interviews with trained female interviewers. Findings from logistic regression analyses indicate that CSA predicts substance use with sexual activity, with variations by CSA coding, type, and characteristics; however, the role of CSA is more limited than expected. Having a main partner with HIV risk mediates some relationships between CSA and drinking four or more drinks prior to sex. Intimate partner violence is the most consistent predictor of sexual risk behaviors. Other salient factors include polysubstance use, depression, social support, recent incarceration, relationship characteristics, and HIV status. This study contributes to understanding of relationships between CSA and HIV sexual risk behaviors and key correlates associated with HIV sexual risk behaviors among women in methadone treatment. It also highlights the complexity of measuring CSA and its association with sexual risk behaviors and the importance of comprehensive approaches to HIV prevention that address psychological, relational, situational, and substance use experiences associated with sexual risk behaviors among this population.

A computational model of spatial visualization capacity.

PubMed

Lyon, Don R; Gunzelmann, Glenn; Gluck, Kevin A

2008-09-01

Visualizing spatial material is a cornerstone of human problem solving, but human visualization capacity is sharply limited. To investigate the sources of this limit, we developed a new task to measure visualization accuracy for verbally-described spatial paths (similar to street directions), and implemented a computational process model to perform it. In this model, developed within the Adaptive Control of Thought-Rational (ACT-R) architecture, visualization capacity is limited by three mechanisms. Two of these (associative interference and decay) are longstanding characteristics of ACT-R's declarative memory. A third (spatial interference) is a new mechanism motivated by spatial proximity effects in our data. We tested the model in two experiments, one with parameter-value fitting, and a replication without further fitting. Correspondence between model and data was close in both experiments, suggesting that the model may be useful for understanding why visualizing new, complex spatial material is so difficult.

[Current treatment situation and progress on bone defect of collapsed tibial plateau fractures].

PubMed

Luo, Chang-qi; Fang, Yue; Tu, Chong-qi; Yang, Tian-fu

2016-02-01

Characteristics of collapsed tibial plateau fracture determines that the joint surface must remain anatomical reduction,line of force in tibial must exist and internal fixation must be strong. However, while renewing articular surface smoothness, surgeons have a lot of problems in dealing with bone defect under the joint surface. Current materials used for bone defect treatment include three categories: autologous bone, allograft bone and bone substitutes. Some scholars think that autologous bone grafts have a number of drawbacks, such as increasing trauma, prolonged operation time, the limited source, bone area bleeding,continuous pain, local infection and anesthesia,but most scholars believe that the autologous cancellous bone graft is still the golden standard. Allograft bone has the ability of bone conduction, but the existence of immune responses, the possibility of a virus infection, and the limited source of the allograft cannot meet the clinical demands. Likewise, bone substitutes have the problem that osteogenesis does not match with degradation in rates. Clinical doctors can meet the demand of the patient's bone graft according to patient's own situation and economic conditions.

Associations Between Personality Disorder Characteristics, Psychological Symptoms, and Sexual Functioning in Young Women.

PubMed

Grauvogl, Andrea; Pelzer, Britt; Radder, Veerle; van Lankveld, Jacques

2018-02-01

Recently, the etiology of sexual dysfunctions in women has been approached from different angles. In clinical practice and in previous studies, it has been observed that women with sexual problems experience anxiety problems and express more rigid and perfectionistic personality traits than women without these problems. To investigate whether personality disorder characteristics according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR) and psychological symptoms are associated with sexual problems in women. 188 women 18 to 25 years old participated in this cross-sectional study. Questionnaires measuring sexual functioning (Female Sexual Function Index), personality disorder characteristics (Assessment of DSM-IV-TR Personality Disorders Questionnaire), and psychological symptoms (Brief Symptom Inventory and Center for Epidemiological Studies Depression Scale) were used. The main outcome measure used was sexual functioning assessed by self-report. Results, using analysis of variance, indicated that women with sexual problems report significantly more cluster A (specifically schizoid) and C (specifically avoidant and obsessive-compulsive) personality disorder characteristics than women without sexual problems. Furthermore, using multiple regression analyses, higher cluster A (specifically schizoid) and lower cluster B (specifically borderline and antisocial) personality disorder characteristics indicated lower levels of sexual functioning. Psychological symptoms partly mediated the effect of cluster A personality disorder characteristics on sexual functioning. The results of this study indicate that clinical practice should extend its scope by focusing more on improving adaptive personality characteristics, such as extraversion and individualism seen in cluster B personality characteristics, and decreasing the perfectionistic, introvert, and self-doubting characteristics seen in cluster C personality characteristics. Because of the correlational design and use of self-report measures, causal relations cannot be established between personality disorder characteristics and sexual functioning. Overall, the results indicate that personality disorder characteristics can play an important associative role in the development and maintenance of sexual functioning problems in women. Grauvogl A, Pelzer B, Radder V, van Lankveld J. Associations Between Personality Disorder Characteristics, Psychological Symptoms, and Sexual Functioning in Young Women. J Sex Med 2018;15:192-200. Copyright © 2017 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Adaptive Sensing of Time Series with Application to Remote Exploration

NASA Technical Reports Server (NTRS)

Thompson, David R.; Cabrol, Nathalie A.; Furlong, Michael; Hardgrove, Craig; Low, Bryan K. H.; Moersch, Jeffrey; Wettergreen, David

2013-01-01

We address the problem of adaptive informationoptimal data collection in time series. Here a remote sensor or explorer agent throttles its sampling rate in order to track anomalous events while obeying constraints on time and power. This problem is challenging because the agent has limited visibility -- all collected datapoints lie in the past, but its resource allocation decisions require predicting far into the future. Our solution is to continually fit a Gaussian process model to the latest data and optimize the sampling plan on line to maximize information gain. We compare the performance characteristics of stationary and nonstationary Gaussian process models. We also describe an application based on geologic analysis during planetary rover exploration. Here adaptive sampling can improve coverage of localized anomalies and potentially benefit mission science yield of long autonomous traverses.

Adolescent female murderers: characteristics and treatment implications.

PubMed

Roe-Sepowitz, Dominique

2007-07-01

This study examines individual and family characteristics of a population of 29 adolescent females charged with homicide or attempted homicide in the juvenile justice system. The purpose of this study is to contribute to the limited knowledge about adolescent females charged with homicide. Data were collected including the MAYSI-2, a risk classification instrument, and social, educational and family histories. Findings include high rates of reported substance use, delinquent peers, early indicators of mental health problems, and limited control and supervision by parents. The most common weapon used was a car and the most common victim was a known person. A comparison was conducted on girls charged with homicide during the commission of another crime or committed during a conflict. The conflict group was found to victimize friends and family significantly more often than the crime group. The crime group showed higher use of alcohol and drugs, used a gun more and had co-offenders at a higher rate. A profile was developed to describe the typical adolescent female homicide offender found in this study. Treatment recommendations and future research were discussed. ((c) 2007 APA, all rights reserved).

Professional development for design-based learning in engineering education: a case study

NASA Astrophysics Data System (ADS)

Gómez Puente, Sonia M.; van Eijck, Michiel; Jochems, Wim

2015-01-01

Design-based learning (DBL) is an educational approach in which students gather and apply theoretical knowledge to solve design problems. In this study, we examined how critical DBL dimensions (project characteristics, design elements, the teacher's role, assessment, and social context) are applied by teachers in the redesign of DBL projects. We conducted an intervention for the professional development of the DBL teachers in the Mechanical Engineering and the Electrical Engineering departments. We used the Experiential Learning Cycle as an educational model for the professionalisation programme. The findings show that the programme encouraged teachers to apply the DBL theoretical framework. However, there are some limitations with regard to specific project characteristics. Further research into supporting teachers to develop open-ended and multidisciplinary activities in the projects that support learning is recommended.

Receiver operating characteristic (ROC) curves: review of methods with applications in diagnostic medicine

NASA Astrophysics Data System (ADS)

Obuchowski, Nancy A.; Bullen, Jennifer A.

2018-04-01

Receiver operating characteristic (ROC) analysis is a tool used to describe the discrimination accuracy of a diagnostic test or prediction model. While sensitivity and specificity are the basic metrics of accuracy, they have many limitations when characterizing test accuracy, particularly when comparing the accuracies of competing tests. In this article we review the basic study design features of ROC studies, illustrate sample size calculations, present statistical methods for measuring and comparing accuracy, and highlight commonly used ROC software. We include descriptions of multi-reader ROC study design and analysis, address frequently seen problems of verification and location bias, discuss clustered data, and provide strategies for testing endpoints in ROC studies. The methods are illustrated with a study of transmission ultrasound for diagnosing breast lesions.

[Mental health characteristics of men who abuse their intimate partners].

PubMed

Calvete, E

2008-10-01

The prevalence of psychopathological disorders amongst men who abuse their intimate partners has yet to be established. This article reviews studies carried out to ascertain the mental health characteristics of male domestic abusers. Most of these studies are based on samples of abusers under treatment or in prison. They generally assess the presence of psychopathological disorders through self-reports and diagnostic interviews are infrequently used. The results of this research show that domestic abusers tend to obtain high points for some types of personality disorders, especially narcissistic, antisocial and borderline disorders. They also present symptoms of depressive disorders and consumption of drugs and alcohol. Some studies also show that neurological problems are relatively frequent. Finally I discuss the limitations of current research and the implications for treatment of domestic abusers.

Hybrid discrete ordinates and characteristics method for solving the linear Boltzmann equation

NASA Astrophysics Data System (ADS)

Yi, Ce

With the ability of computer hardware and software increasing rapidly, deterministic methods to solve the linear Boltzmann equation (LBE) have attracted some attention for computational applications in both the nuclear engineering and medical physics fields. Among various deterministic methods, the discrete ordinates method (SN) and the method of characteristics (MOC) are two of the most widely used methods. The SN method is the traditional approach to solve the LBE for its stability and efficiency. While the MOC has some advantages in treating complicated geometries. However, in 3-D problems requiring a dense discretization grid in phase space (i.e., a large number of spatial meshes, directions, or energy groups), both methods could suffer from the need for large amounts of memory and computation time. In our study, we developed a new hybrid algorithm by combing the two methods into one code, TITAN. The hybrid approach is specifically designed for application to problems containing low scattering regions. A new serial 3-D time-independent transport code has been developed. Under the hybrid approach, the preferred method can be applied in different regions (blocks) within the same problem model. Since the characteristics method is numerically more efficient in low scattering media, the hybrid approach uses a block-oriented characteristics solver in low scattering regions, and a block-oriented SN solver in the remainder of the physical model. In the TITAN code, a physical problem model is divided into a number of coarse meshes (blocks) in Cartesian geometry. Either the characteristics solver or the SN solver can be chosen to solve the LBE within a coarse mesh. A coarse mesh can be filled with fine meshes or characteristic rays depending on the solver assigned to the coarse mesh. Furthermore, with its object-oriented programming paradigm and layered code structure, TITAN allows different individual spatial meshing schemes and angular quadrature sets for each coarse mesh. Two quadrature types (level-symmetric and Legendre-Chebyshev quadrature) along with the ordinate splitting techniques (rectangular splitting and PN-TN splitting) are implemented. In the S N solver, we apply a memory-efficient 'front-line' style paradigm to handle the fine mesh interface fluxes. In the characteristics solver, we have developed a novel 'backward' ray-tracing approach, in which a bi-linear interpolation procedure is used on the incoming boundaries of a coarse mesh. A CPU-efficient scattering kernel is shared in both solvers within the source iteration scheme. Angular and spatial projection techniques are developed to transfer the angular fluxes on the interfaces of coarse meshes with different discretization grids. The performance of the hybrid algorithm is tested in a number of benchmark problems in both nuclear engineering and medical physics fields. Among them are the Kobayashi benchmark problems and a computational tomography (CT) device model. We also developed an extra sweep procedure with the fictitious quadrature technique to calculate angular fluxes along directions of interest. The technique is applied in a single photon emission computed tomography (SPECT) phantom model to simulate the SPECT projection images. The accuracy and efficiency of the TITAN code are demonstrated in these benchmarks along with its scalability. A modified version of the characteristics solver is integrated in the PENTRAN code and tested within the parallel engine of PENTRAN. The limitations on the hybrid algorithm are also studied.

Torque Limits for Fasteners in Composites

NASA Technical Reports Server (NTRS)

Zhao, Yi

2002-01-01

The two major classes of laminate joints are bonded and bolted. Often the two classes are combined as bonded-bolted joints. Several characteristics of fiber reinforced composite materials render them more susceptible to joint problems than conventional metals. These characteristics include weakness in in-plane shear, transverse tension/compression, interlaminar shear, and bearing strength relative to the strength and stiffness in the fiber direction. Studies on bolted joints of composite materials have been focused on joining assembly subject to in-plane loads. Modes of failure under these loading conditions are net-tension failure, cleavage tension failure, shear-out failure, bearing failure, etc. Although the studies of torque load can be found in literature, they mainly discussed the effect of the torque load on in-plane strength. Existing methods for calculating torque limit for a mechanical fastener do not consider connecting members. The concern that a composite member could be crushed by a preload inspired the initiation of this study. The purpose is to develop a fundamental knowledge base on how to determine a torque limit when a composite member is taken into account. Two simplified analytical models were used: a stress failure analysis model based on maximum stress criterion, and a strain failure analysis model based on maximum strain criterion.

Physical health symptoms reported by trafficked women receiving post-trafficking support in Moldova: prevalence, severity and associated factors

PubMed Central

2012-01-01

Background Many trafficked people suffer high levels of physical, sexual and psychological abuse. Yet, there has been limited research on the physical health problems associated with human trafficking or how the health needs of women in post-trafficking support settings vary according to socio-demographic or trafficking characteristics. Methods We analysed the prevalence and severity of 15 health symptoms reported by 120 trafficked women who had returned to Moldova between December 2007 and December 2008 and were registered with the International Organisation for Migration Assistance and Protection Programme. Women had returned to Moldova an average of 5.9 months prior to interview (range 2-12 months). Results Headaches (61.7%), stomach pain (60.9%), memory problems (44.2%), back pain (42.5%), loss of appetite (35%), and tooth pain (35%) were amongst the most commonly reported symptoms amongst both women trafficked for sexual exploitation and women trafficked for labour exploitation. The prevalence of headache and memory problems was strongly associated with duration of exploitation. Conclusions Trafficked women who register for post-trafficking support services after returning to their country of origin are likely to have long-term physical and dental health needs and should be provided with access to comprehensive medical services. Health problems among women who register for post-trafficking support services after returning to their country of origin are not limited to women trafficked for sexual exploitation but are also experienced by victims of labour exploitation. PMID:22834807

Diffusion archeology for diffusion progression history reconstruction.

PubMed

Sefer, Emre; Kingsford, Carl

2016-11-01

Diffusion through graphs can be used to model many real-world processes, such as the spread of diseases, social network memes, computer viruses, or water contaminants. Often, a real-world diffusion cannot be directly observed while it is occurring - perhaps it is not noticed until some time has passed, continuous monitoring is too costly, or privacy concerns limit data access. This leads to the need to reconstruct how the present state of the diffusion came to be from partial diffusion data. Here, we tackle the problem of reconstructing a diffusion history from one or more snapshots of the diffusion state. This ability can be invaluable to learn when certain computer nodes are infected or which people are the initial disease spreaders to control future diffusions. We formulate this problem over discrete-time SEIRS-type diffusion models in terms of maximum likelihood. We design methods that are based on submodularity and a novel prize-collecting dominating-set vertex cover (PCDSVC) relaxation that can identify likely diffusion steps with some provable performance guarantees. Our methods are the first to be able to reconstruct complete diffusion histories accurately in real and simulated situations. As a special case, they can also identify the initial spreaders better than the existing methods for that problem. Our results for both meme and contaminant diffusion show that the partial diffusion data problem can be overcome with proper modeling and methods, and that hidden temporal characteristics of diffusion can be predicted from limited data.

Diffusion archeology for diffusion progression history reconstruction

PubMed Central

Sefer, Emre; Kingsford, Carl

2015-01-01

Diffusion through graphs can be used to model many real-world processes, such as the spread of diseases, social network memes, computer viruses, or water contaminants. Often, a real-world diffusion cannot be directly observed while it is occurring — perhaps it is not noticed until some time has passed, continuous monitoring is too costly, or privacy concerns limit data access. This leads to the need to reconstruct how the present state of the diffusion came to be from partial diffusion data. Here, we tackle the problem of reconstructing a diffusion history from one or more snapshots of the diffusion state. This ability can be invaluable to learn when certain computer nodes are infected or which people are the initial disease spreaders to control future diffusions. We formulate this problem over discrete-time SEIRS-type diffusion models in terms of maximum likelihood. We design methods that are based on submodularity and a novel prize-collecting dominating-set vertex cover (PCDSVC) relaxation that can identify likely diffusion steps with some provable performance guarantees. Our methods are the first to be able to reconstruct complete diffusion histories accurately in real and simulated situations. As a special case, they can also identify the initial spreaders better than the existing methods for that problem. Our results for both meme and contaminant diffusion show that the partial diffusion data problem can be overcome with proper modeling and methods, and that hidden temporal characteristics of diffusion can be predicted from limited data. PMID:27821901

Physical health symptoms reported by trafficked women receiving post-trafficking support in Moldova: prevalence, severity and associated factors.

PubMed

Oram, Siân; Ostrovschi, Nicolae V; Gorceag, Viorel I; Hotineanu, Mihai A; Gorceag, Lilia; Trigub, Carolina; Abas, Melanie

2012-07-26

Many trafficked people suffer high levels of physical, sexual and psychological abuse. Yet, there has been limited research on the physical health problems associated with human trafficking or how the health needs of women in post-trafficking support settings vary according to socio-demographic or trafficking characteristics. We analysed the prevalence and severity of 15 health symptoms reported by 120 trafficked women who had returned to Moldova between December 2007 and December 2008 and were registered with the International Organisation for Migration Assistance and Protection Programme. Women had returned to Moldova an average of 5.9 months prior to interview (range 2-12 months). Headaches (61.7%), stomach pain (60.9%), memory problems (44.2%), back pain (42.5%), loss of appetite (35%), and tooth pain (35%) were amongst the most commonly reported symptoms amongst both women trafficked for sexual exploitation and women trafficked for labour exploitation. The prevalence of headache and memory problems was strongly associated with duration of exploitation. Trafficked women who register for post-trafficking support services after returning to their country of origin are likely to have long-term physical and dental health needs and should be provided with access to comprehensive medical services. Health problems among women who register for post-trafficking support services after returning to their country of origin are not limited to women trafficked for sexual exploitation but are also experienced by victims of labour exploitation.

Mathematical model of the methane replacement by carbon dioxide in the gas hydrate reservoir taking into account the diffusion kinetics

NASA Astrophysics Data System (ADS)

Musakaev, N. G.; Khasanov, M. K.; Rafikova, G. R.

2018-03-01

The problem of the replacement of methane in its hydrate by carbon dioxide in a porous medium is considered. The gas-exchange kinetics scheme is proposed in which the intensity of the process is limited by the diffusion of CO2 through the hydrate layer formed between the gas mixture flow and the CH4 hydrate. Dynamics of the main parameters of the process is numerically investigated. The main characteristic stages of the process are determined.

Fused Deposition Technique for Continuous Fiber Reinforced Thermoplastic

NASA Astrophysics Data System (ADS)

Bettini, Paolo; Alitta, Gianluca; Sala, Giuseppe; Di Landro, Luca

2017-02-01

A simple technique for the production of continuous fiber reinforced thermoplastic by fused deposition modeling, which involves a common 3D printer with quite limited modifications, is presented. An adequate setting of processing parameters and deposition path allows to obtain components with well-enhanced mechanical characteristics compared to conventional 3D printed items. The most relevant problems related to the simultaneous feeding of fibers and polymer are discussed. The properties of obtained aramid fiber reinforced polylactic acid (PLA) in terms of impregnation quality and of mechanical response are measured.

Role of Kinetic Modeling in Biomedical Imaging

PubMed Central

Huang, Sung-Cheng

2009-01-01

Biomedical imaging can reveal clear 3-dimensional body morphology non-invasively with high spatial resolution. Its efficacy, in both clinical and pre-clinical settings, is enhanced with its capability to provide in vivo functional/biological information in tissue. The role of kinetic modeling in providing biological/functional information in biomedical imaging is described. General characteristics and limitations in extracting biological information are addressed and practical approaches to solve the problems are discussed and illustrated with examples. Some future challenges and opportunities for kinetic modeling to expand the capability of biomedical imaging are also presented. PMID:20640185

Khat use and related addiction, mental health and physical disorders: the need to address a growing risk.

PubMed

Odenwald, Michael; al'Absi, Mustafa

2017-05-01

Khat use is a drug problem characteristic of the Eastern Mediterranean Region, which is a widespread culturally accepted practice in some countries and is becoming more prevalent in others. Although limited use may not be accompanied by serious consequences, prolonged exposure could lead to dependence, psychosis and other psychiatric disorders and physical conditions such as hypertension, cardiovascular complications, sexual dysfunction, hepatoxicity and reduced birth weight of infants born to khat-chewing mothers. The widespread use and its burden on health and economy has raised concerns in the Region, although the extent of the problem is not well assessed. Additionally, most countries do not have a clear policy and plan with regard to khat use, and therefore there is hardly any structured prevention and treatment plan in place to respond to the problem. This review presents a picture of the extent of the problem, elaborates on related existing research initiatives and international treaties, policies and health service provisions, and outlines best policy and programme interventions in khat-use countries.

Expert system technology

NASA Technical Reports Server (NTRS)

Prince, Mary Ellen

1987-01-01

The expert system is a computer program which attempts to reproduce the problem-solving behavior of an expert, who is able to view problems from a broad perspective and arrive at conclusions rapidly, using intuition, shortcuts, and analogies to previous situations. Expert systems are a departure from the usual artificial intelligence approach to problem solving. Researchers have traditionally tried to develop general modes of human intelligence that could be applied to many different situations. Expert systems, on the other hand, tend to rely on large quantities of domain specific knowledge, much of it heuristic. The reasoning component of the system is relatively simple and straightforward. For this reason, expert systems are often called knowledge based systems. The report expands on the foregoing. Section 1 discusses the architecture of a typical expert system. Section 2 deals with the characteristics that make a problem a suitable candidate for expert system solution. Section 3 surveys current technology, describing some of the software aids available for expert system development. Section 4 discusses the limitations of the latter. The concluding section makes predictions of future trends.

Care arrangements, grief and psychological problems among children orphaned by AIDS in China.

PubMed

Zhao, G; Li, X; Fang, X; Zhao, J; Yang, H; Stanton, B

2007-10-01

The China Ministry of Health has estimated that there are at least 100,000 AIDS orphans in China. The UNICEF China Office estimates that between 150,000 and 250,000 additional children will be orphaned by AIDS over the next five years. However, limited data are available regarding the sociodemographic characteristics, care arrangements, barriers to appropriate grief resolution and psychological problems among AIDS orphans in China. In this article, we review secondary data and reports from scientific literature, government, non-governmental organisations and public media regarding children orphaned by AIDS in China to address their living situation, bereavement process and psychological problems. Our review suggests that AIDS orphans in China are living in a stressful environment, with many orphans struggling with psychological problems and unmet basic needs such as food, shelter, education and medical care. Based on our review, we suggest that future studies should address the psychosocial needs of AIDS orphans in China and develop health promotion programmes to mitigate the negative impact of parental death on the physical and psychosocial well-being of these orphans.

Care arrangement, grief, and psychological problems among children orphaned by AIDS in China

PubMed Central

Zhao, Guoxiang; Li, Xiaoming; Fang, Xiaoyi; Zhao, Junfeng; Yang, Hongmei; Stanton, Bonita

2007-01-01

The China Ministry of Health has estimated that there are at least 100,000 AIDS orphans in China. The UNICEF China Office estimates that between 150,000 and 250,000 additional children will be orphaned by AIDS over the next five years. However, limited data are available regarding the socio-demographic characteristics, care arrangement, barriers to appropriate grief resolution and psychological problems among AIDS orphans in China. In this article, we review secondary data and reports from scientific literature, government, non-governmental organizations, and public media regarding children orphaned by AIDS in China to address their living situation, bereavement process, and psychological problems. Our review suggests that AIDS orphans in China are living in a stressful environment with many orphans struggling with psychological problems and unmet basic needs such as food, shelter, education, and medical care. Based on our review, we suggest that future studies should address the psychosocial needs of AIDS orphans in China and develop health promotion programs to mitigate the negative impact of parental death on the physical and psychosocial well-being of these orphans. PMID:18058390

Mental Health Problems in Children with Prader-Willi Syndrome

PubMed Central

Skokauskas, Norbert; Sweeny, Eileen; Meehan, Judith; Gallagher, Louise

2012-01-01

Background: Prader-Willi Syndrome (PWS) is a genetically determined neurodevelopmental disorder, which occurs in approximately one in 22000 births. Aims: This study aimed to investigate psychiatric characteristics of children diagnosed with PWS compared with an age-, gender- and IQ-matched control group. The parents of children with PWS were assessed for psychological distress in comparison to the parents of the control group. Methodological limitations identified in previous studies were addressed in the present study. Methods: Psychiatric problems were evaluated in a sample of children with genetically confirmed PWS and an age- and IQ-matched control group using the Child Behaviour Checklist 6–18. Parental psychological distress for both groups was evaluated with the Brief Symptom Inventory. Results: Children with PWS had more severe somatic, social, and thought problems, and were more withdrawn-depressed in comparison to controls. Borderline difficulties were detected for the affective, somatic, and attention deficit-hyperactivity CBCL DSM-orientated subscales in the PWS group. Parents of PWS children, in comparison to controls, had more somatization, phobic anxiety, obsessive-compulsive, and anxiety problems. Conclusions: PWS represents a complex psychological disorder with multiple areas of disturbances. PMID:22876265

A solution quality assessment method for swarm intelligence optimization algorithms.

PubMed

Zhang, Zhaojun; Wang, Gai-Ge; Zou, Kuansheng; Zhang, Jianhua

2014-01-01

Nowadays, swarm intelligence optimization has become an important optimization tool and wildly used in many fields of application. In contrast to many successful applications, the theoretical foundation is rather weak. Therefore, there are still many problems to be solved. One problem is how to quantify the performance of algorithm in finite time, that is, how to evaluate the solution quality got by algorithm for practical problems. It greatly limits the application in practical problems. A solution quality assessment method for intelligent optimization is proposed in this paper. It is an experimental analysis method based on the analysis of search space and characteristic of algorithm itself. Instead of "value performance," the "ordinal performance" is used as evaluation criteria in this method. The feasible solutions were clustered according to distance to divide solution samples into several parts. Then, solution space and "good enough" set can be decomposed based on the clustering results. Last, using relative knowledge of statistics, the evaluation result can be got. To validate the proposed method, some intelligent algorithms such as ant colony optimization (ACO), particle swarm optimization (PSO), and artificial fish swarm algorithm (AFS) were taken to solve traveling salesman problem. Computational results indicate the feasibility of proposed method.

Transport synthetic acceleration for long-characteristics assembly-level transport problems

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

Zika, M.R.; Adams, M.L.

2000-02-01

The authors apply the transport synthetic acceleration (TSA) scheme to the long-characteristics spatial discretization for the two-dimensional assembly-level transport problem. This synthetic method employs a simplified transport operator as its low-order approximation. Thus, in the acceleration step, the authors take advantage of features of the long-characteristics discretization that make it particularly well suited to assembly-level transport problems. The main contribution is to address difficulties unique to the long-characteristics discretization and produce a computationally efficient acceleration scheme. The combination of the long-characteristics discretization, opposing reflecting boundary conditions (which are present in assembly-level transport problems), and TSA presents several challenges. The authorsmore » devise methods for overcoming each of them in a computationally efficient way. Since the boundary angular data exist on different grids in the high- and low-order problems, they define restriction and prolongation operations specific to the method of long characteristics to map between the two grids. They implement the conjugate gradient (CG) method in the presence of opposing reflection boundary conditions to solve the TSA low-order equations. The CG iteration may be applied only to symmetric positive definite (SPD) matrices; they prove that the long-characteristics discretization yields an SPD matrix. They present results of the acceleration scheme on a simple test problem, a typical pressurized water reactor assembly, and a typical boiling water reactor assembly.« less

Farmers' perceptions of land degradation and their investments in land management: a case study in the Central Rift Valley of Ethiopia.

PubMed

Adimassu, Zenebe; Kessler, Aad; Yirga, Chilot; Stroosnijder, Leo

2013-05-01

To combat land degradation in the Central Rift Valley (CRV) of Ethiopia, farmers are of crucial importance. If farmers perceive land degradation as a problem, the chance that they invest in land management measures will be enhanced. This study presents farmers' perceptions of land degradation and their investments in land management, and to what extent the latter are influenced by these perceptions. Water erosion and fertility depletion are taken as main indicators of land degradation, and the results show that farmers perceive an increase in both indicators over the last decade. They are aware of it and consider it as a problem. Nevertheless, farmers' investments to control water erosion and soil fertility depletion are very limited in the CRV. Results also show that farmers' awareness of both water erosion and soil fertility decline as a problem is not significantly associated with their investments in land management. Hence, even farmers who perceive land degradation on their fields and are concerned about its increase over the last decade do not significantly invest more in water erosion and soil fertility control measures than farmers who do not perceive these phenomena. Further research is needed to assess which other factors might influence farmers' investments in land management, especially factors related to socioeconomic characteristics of farm households and plot characteristics which were not addressed by this study.

Testing Scientific Software: A Systematic Literature Review.

PubMed

Kanewala, Upulee; Bieman, James M

2014-10-01

Scientific software plays an important role in critical decision making, for example making weather predictions based on climate models, and computation of evidence for research publications. Recently, scientists have had to retract publications due to errors caused by software faults. Systematic testing can identify such faults in code. This study aims to identify specific challenges, proposed solutions, and unsolved problems faced when testing scientific software. We conducted a systematic literature survey to identify and analyze relevant literature. We identified 62 studies that provided relevant information about testing scientific software. We found that challenges faced when testing scientific software fall into two main categories: (1) testing challenges that occur due to characteristics of scientific software such as oracle problems and (2) testing challenges that occur due to cultural differences between scientists and the software engineering community such as viewing the code and the model that it implements as inseparable entities. In addition, we identified methods to potentially overcome these challenges and their limitations. Finally we describe unsolved challenges and how software engineering researchers and practitioners can help to overcome them. Scientific software presents special challenges for testing. Specifically, cultural differences between scientist developers and software engineers, along with the characteristics of the scientific software make testing more difficult. Existing techniques such as code clone detection can help to improve the testing process. Software engineers should consider special challenges posed by scientific software such as oracle problems when developing testing techniques.

Models based on "out-of Kilter" algorithm

NASA Astrophysics Data System (ADS)

Adler, M. J.; Drobot, R.

2012-04-01

In case of many water users along the river stretches, it is very important, in case of low flows and droughty periods to develop an optimization model for water allocation, to cover all needs under certain predefined constraints, depending of the Contingency Plan for drought management. Such a program was developed during the implementation of the WATMAN Project, in Romania (WATMAN Project, 2005-2006, USTDA) for Arges-Dambovita-Ialomita Basins water transfers. This good practice was proposed for WATER CoRe Project- Good Practice Handbook for Drought Management, (InterregIVC, 2011), to be applied for the European Regions. Two types of simulation-optimization models based on an improved version of out-of-kilter algorithm as optimization technique have been developed and used in Romania: • models for founding of the short-term operation of a WMS, • models generically named SIMOPT that aim to the analysis of long-term WMS operation and have as the main results the statistical WMS functional parameters. A real WMS is modeled by an arcs-nodes network so the real WMS operation problem becomes a problem of flows in networks. The nodes and oriented arcs as well as their characteristics such as lower and upper limits and associated costs are the direct analog of the physical and operational WMS characteristics. Arcs represent both physical and conventional elements of WMS such as river branches, channels or pipes, water user demands or other water management requirements, trenches of water reservoirs volumes, water levels in channels or rivers, nodes are junctions of at least two arcs and stand for locations of lakes or water reservoirs and/or confluences of river branches, water withdrawal or wastewater discharge points, etc. Quantitative features of water resources, water users and water reservoirs or other water works are expressed as constraints of non-violating the lower and upper limits assigned on arcs. Options of WMS functioning i.e. water retention/discharge in/from the reservoirs or diversion of water from one part of WMS to the other in order to meet water demands as well as the water user economic benefit or loss related to the degree of water demand, are the defining elements of the objective function and are conventionally expressed by the means of costs attached to the arcs. The problem of optimizing the WMS operation is formulated like a flow in networks problem as following: to find the flow that minimize the cost in the whole network while meeting the constraints of continuity in nodes and the constraints of non-exceeding lower and upper flow limits on arcs. Conversion of WMS in the arcs-nodes network and the adequate choice of costs and limits on arcs are steps of a unitary process and depend on the goal of the respective model.

Delamination detection using methods of computational intelligence

NASA Astrophysics Data System (ADS)

Ihesiulor, Obinna K.; Shankar, Krishna; Zhang, Zhifang; Ray, Tapabrata

2012-11-01

Abstract Reliable delamination prediction scheme is indispensable in order to prevent potential risks of catastrophic failures in composite structures. The existence of delaminations changes the vibration characteristics of composite laminates and hence such indicators can be used to quantify the health characteristics of laminates. An approach for online health monitoring of in-service composite laminates is presented in this paper that relies on methods based on computational intelligence. Typical changes in the observed vibration characteristics (i.e. change in natural frequencies) are considered as inputs to identify the existence, location and magnitude of delaminations. The performance of the proposed approach is demonstrated using numerical models of composite laminates. Since this identification problem essentially involves the solution of an optimization problem, the use of finite element (FE) methods as the underlying tool for analysis turns out to be computationally expensive. A surrogate assisted optimization approach is hence introduced to contain the computational time within affordable limits. An artificial neural network (ANN) model with Bayesian regularization is used as the underlying approximation scheme while an improved rate of convergence is achieved using a memetic algorithm. However, building of ANN surrogate models usually requires large training datasets. K-means clustering is effectively employed to reduce the size of datasets. ANN is also used via inverse modeling to determine the position, size and location of delaminations using changes in measured natural frequencies. The results clearly highlight the efficiency and the robustness of the approach.

Contagion Shocks in One Dimension

NASA Astrophysics Data System (ADS)

Bertozzi, Andrea L.; Rosado, Jesus; Short, Martin B.; Wang, Li

2015-02-01

We consider an agent-based model of emotional contagion coupled with motion in one dimension that has recently been studied in the computer science community. The model involves movement with a speed proportional to a "fear" variable that undergoes a temporal consensus averaging based on distance to other agents. We study the effect of Riemann initial data for this problem, leading to shock dynamics that are studied both within the agent-based model as well as in a continuum limit. We examine the behavior of the model under distinguished limits as the characteristic contagion interaction distance and the interaction timescale both approach zero. The limiting behavior is related to a classical model for pressureless gas dynamics with "sticky" particles. In comparison, we observe a threshold for the interaction distance vs. interaction timescale that produce qualitatively different behavior for the system - in one case particle paths do not cross and there is a natural Eulerian limit involving nonlocal interactions and in the other case particle paths can cross and one may consider only a kinetic model in the continuum limit.

Effects of the target aspect ratio and intrinsic reactivity onto diffusive search in bounded domains

NASA Astrophysics Data System (ADS)

Grebenkov, Denis S.; Metzler, Ralf; Oshanin, Gleb

2017-10-01

We study the mean first passage time (MFPT) to a reaction event on a specific site in a cylindrical geometry—characteristic, for instance, for bacterial cells, with a concentric inner cylinder representing the nuclear region of the bacterial cell. A similar problem emerges in the description of a diffusive search by a transcription factor protein for a specific binding region on a single strand of DNA. We develop a unified theoretical approach to study the underlying boundary value problem which is based on a self-consistent approximation of the mixed boundary condition. Our approach permits us to derive explicit, novel, closed-form expressions for the MFPT valid for a generic setting with an arbitrary relation between the system parameters. We analyse this general result in the asymptotic limits appropriate for the above-mentioned biophysical problems. Our investigation reveals the crucial role of the target aspect ratio and of the intrinsic reactivity of the binding region, which were disregarded in previous studies. Theoretical predictions are confirmed by numerical simulations.

Piloted simulation study of the effects of an automated trim system on flight characteristics of a light twin-engine airplane with one engine inoperative

NASA Technical Reports Server (NTRS)

Stewart, E. C.; Brown, P. W.; Yenni, K. R.

1986-01-01

A simulation study was conducted to investigate the piloting problems associated with failure of an engine on a generic light twin-engine airplane. A primary piloting problem for a light twin-engine airplane after an engine failure is maintaining precise control of the airplane in the presence of large steady control forces. To address this problem, a simulated automatic trim system which drives the trim tabs as an open-loop function of propeller slipstream measurements was developed. The simulated automatic trim system was found to greatly increase the controllability in asymmetric powered flight without having to resort to complex control laws or an irreversible control system. However, the trim-tab control rates needed to produce the dramatic increase in controllability may require special design consideration for automatic trim system failures. Limited measurements obtained in full-scale flight tests confirmed the fundamental validity of the proposed control law.

Implementing a comprehensive program for the prevention of conduct problems in rural communities: the Fast Track experience. The Conduct Problems Prevention Research Group.

PubMed

Bierman, K L

1997-08-01

Childhood conduct problems are predictive of a number of serious long-term difficulties (e.g., school failure, delinquent behavior, and mental health problems), making the design of effective prevention programs a priority. The Fast Track Program is a demonstration project currently underway in four demographically diverse areas of the United States, testing the feasibility and effectiveness of a comprehensive, multicomponent prevention program targeting children at risk for conduct disorders. This paper describes some lessons learned about the implementation of this program in a rural area. Although there are many areas of commonality in terms of program needs, program design, and implementation issues in rural and urban sites, rural areas differ from urban areas along the dimensions of geographical dispersion and regionalism, and community stability and insularity. Rural programs must cover a broad geographical area and must be sensitive to the multiple, small and regional communities that constitute their service area. Small schools, homogeneous populations, traditional values, limited recreational, educational and mental health services, and politically conservative climates are all more likely to emerge as characteristics of rural rather than urban sites (Sherman, 1992). These characteristics may both pose particular challenges to the implementation of prevention programs in rural areas, as well as offer particular benefits. Three aspects of program implementation are described in detail: (a) community entry and program initiation in rural areas, (b) the adaptation of program components and service delivery to meet the needs of rural families and schools, and (c) issues in administrative organization of a broadly dispersed tricounty rural prevention program.

Are medical marijuana users different from recreational users? The view from primary care.

PubMed

Roy-Byrne, Peter; Maynard, Charles; Bumgardner, Kristin; Krupski, Antoinette; Dunn, Chris; West, Imara I; Donovan, Dennis; Atkins, David C; Ries, Richard

2015-10-01

Marijuana is currently approved for medical use in 23 states. Both clinicians and the lay public have questioned whether users of marijuana for medical purposes are different from users of marijuana for recreational purposes. This study examined similarities and differences in important clinical characteristics between users of medical marijuana and users of recreational marijuana. The sample consisted of 868 adult primary care patients in Washington State, who reported use of medical marijuana (n = 131), recreational marijuana (n = 525), or drugs other than marijuana (n = 212). Retention was over 87% at 3-, 6-, 9-, and 12-month assessments. The majority of medical, psychiatric, substance use, and service utilization characteristic comparisons were not significant. However, medical marijuana users had significantly more medical problems, a significantly larger proportion reported >15 days medical problems in the past month, and significantly smaller proportions reported no pain and no mobility limitations (p < .001). Medical marijuana users also had significantly lower drug problem severity, lower alcohol problem severity, and significantly larger proportions reported using marijuana alone and concomitant opioid use only (p < .001). There was no significant difference between medical and recreational users in the percentage using marijuana with at least two additional substances (48% vs. 58%, respectively, p = .05). Although our results suggest that there are few distinct differences between medical and recreational users of marijuana, the differences observed, while mostly very small in effect size (<.2), are consistent with at least some medical users employing marijuana to relieve symptoms and distress associated with medical illness. © American Academy of Addiction Psychiatry.

Real-time digital signal recovery for a multi-pole low-pass transfer function system.

PubMed

Lee, Jhinhwan

2017-08-01

In order to solve the problems of waveform distortion and signal delay by many physical and electrical systems with multi-pole linear low-pass transfer characteristics, a simple digital-signal-processing (DSP)-based method of real-time recovery of the original source waveform from the distorted output waveform is proposed. A mathematical analysis on the convolution kernel representation of the single-pole low-pass transfer function shows that the original source waveform can be accurately recovered in real time using a particular moving average algorithm applied on the input stream of the distorted waveform, which can also significantly reduce the overall delay time constant. This method is generalized for multi-pole low-pass systems and has noise characteristics of the inverse of the low-pass filter characteristics. This method can be applied to most sensors and amplifiers operating close to their frequency response limits to improve the overall performance of data acquisition systems and digital feedback control systems.

Overview of Risk Mitigation for Safety-Critical Computer-Based Systems

NASA Technical Reports Server (NTRS)

Torres-Pomales, Wilfredo

2015-01-01

This report presents a high-level overview of a general strategy to mitigate the risks from threats to safety-critical computer-based systems. In this context, a safety threat is a process or phenomenon that can cause operational safety hazards in the form of computational system failures. This report is intended to provide insight into the safety-risk mitigation problem and the characteristics of potential solutions. The limitations of the general risk mitigation strategy are discussed and some options to overcome these limitations are provided. This work is part of an ongoing effort to enable well-founded assurance of safety-related properties of complex safety-critical computer-based aircraft systems by developing an effective capability to model and reason about the safety implications of system requirements and design.

Tuberculosis patients hospitalized in the Albert Schweitzer Hospital, Lambaréné, Gabon-a retrospective observational study.

PubMed

Stolp, S M; Huson, M A M; Janssen, S; Beyeme, J O; Grobusch, M P

2013-11-01

Epidemiological data on tuberculosis in Central Africa are limited. We performed a retrospective observational study on clinical characteristics of 719 hospitalized tuberculosis patients in Lambaréné, Gabon. Human immunodeficiency virus (HIV) co-infection rate was high (34%) and in-hospital mortality was significantly higher in HIV-positive patients (10% versus 2%). Long-term information on patient outcome was limited; however, from 2008 to 2011, loss to follow up was noted in 28% of cases. Our data illustrate the high burden of TB in Gabon, where loss to follow up and emerging drug resistance are important problems for which comprehensive data are still lacking. © 2013 The Authors Clinical Microbiology and Infection © 2013 European Society of Clinical Microbiology and Infectious Diseases.

Characteristics of Effective Disaster Responders and Leaders: A Survey of Disaster Medical Practitioners.

PubMed

King, Richard V; Larkin, Gregory Luke; Fowler, Raymond L; Downs, Dana L; North, Carol S

2016-10-01

To identify key attributes of effective disaster/mass casualty first responders and leaders, thereby informing the ongoing development of a capable disaster health workforce. We surveyed emergency response practitioners attending a conference session, the EMS State of the Science: A Gathering of Eagles. We used open-ended questions to ask participants to describe key characteristics of successful disaster/mass casualty first responders and leaders. Of the 140 session attendees, 132 (94%) participated in the survey. All responses were categorized by using a previously developed framework. The most frequently mentioned characteristics were related to incident command/disaster knowledge, teamwork/interpersonal skills, performing one's role, and cognitive abilities. Other identified characteristics were related to communication skills, adaptability/flexibility, problem solving/decision-making, staying calm and cool under stress, personal character, and overall knowledge. The survey findings support our prior focus group conclusion that important characteristics of disaster responders and leaders are not limited to the knowledge and skills typically included in disaster training. Further research should examine the extent to which these characteristics are consistently associated with actual effective performance of disaster response personnel and determine how best to incorporate these attributes into competency models, processes, and tools for the development of an effective disaster response workforce. (Disaster Med Public Health Preparedness. 2016;page 1 of 4).

Self-similar space-time evolution of an initial density discontinuity

NASA Astrophysics Data System (ADS)

Rekaa, V. L.; Pécseli, H. L.; Trulsen, J. K.

2013-07-01

The space-time evolution of an initial step-like plasma density variation is studied. We give particular attention to formulate the problem in a way that opens for the possibility of realizing the conditions experimentally. After a short transient time interval of the order of the electron plasma period, the solution is self-similar as illustrated by a video where the space-time evolution is reduced to be a function of the ratio x/t. Solutions of this form are usually found for problems without characteristic length and time scales, in our case the quasi-neutral limit. By introducing ion collisions with neutrals into the numerical analysis, we introduce a length scale, the collisional mean free path. We study the breakdown of the self-similarity of the solution as the mean free path is made shorter than the system length. Analytical results are presented for charge exchange collisions, demonstrating a short time collisionless evolution with an ensuing long time diffusive relaxation of the initial perturbation. For large times, we find a diffusion equation as the limiting analytical form for a charge-exchange collisional plasma, with a diffusion coefficient defined as the square of the ion sound speed divided by the (constant) ion collision frequency. The ion-neutral collision frequency acts as a parameter that allows a collisionless result to be obtained in one limit, while the solution of a diffusion equation is recovered in the opposite limit of large collision frequencies.

How learning one category influences the learning of another: intercategory generalization based on analogy and specific stimulus information.

PubMed

Nahinsky, Irwin D; Lucas, Barbara A; Edgell, Stephen E; Overfelt, Joseph; Loeb, Richard

2004-01-01

We investigated the effect of learning one category structure on the learning of a related category structure. Photograph-name combinations, called identifiers, were associated with values of four demographic attributes. Two problems were related by analogous demographic attributes, common identifiers, or both to examine the impact of common identifier, related general characteristics, and the interaction of the two variables in mediating learning transfer from one category structure to another. Problems sharing the same identifier information prompted greater positive transfer than those not sharing the same identifier information. In contrast, analogous defining characteristics in the two problems did not facilitate transfer. We computed correlations between responses to first-problem stimuli and responses to analogous second-problem stimuli for each participant. The analogous characteristics produced a tendency to respond in the same way to corresponding stimuli in the two problems. The results support an alignment between category structures related by analogous defining characteristics, which is facilitated by specific identifier information shared by two category structures.

High-Fluence Light-Emitting Diode-Generated Red Light Modulates the Transforming Growth Factor-Beta Pathway in Human Skin Fibroblasts.

PubMed

Mamalis, Andrew; Jagdeo, Jared

2018-05-24

Skin fibrosis is a significant medical problem with limited available treatment modalities. The key cellular characteristics include increased fibroblast proliferation, collagen production, and transforming growth factor-beta (TGF-B)/SMAD pathway signaling. The authors have previously shown that high-fluence light-emitting diode red light (HF-LED-RL) decreases cellular proliferation and collagen production. Herein, the authors investigate the ability of HF-LED-RL to modulate the TGF-B/SMAD pathway. Normal human dermal fibroblasts were cultured and irradiated with a commercially available hand-held LED array. After irradiation, cell lysates were collected and levels of pSMAD2, TGF-Beta 1, and TGF-Beta I receptor were measured using Western blot. High-fluence light-emitting diode red light decreased TGF-Beta 1 ligand (TGF-B1) levels after irradiation. 320 J/cm HF-LED-RL resulted in 59% TGF-B1 and 640 J/cm HF-LED-RL resulted in 54% TGF-B1, relative to controls. 640 J/cm HF-LED-RL resulted in 62% pSMAD2 0 hours after irradiation, 65% pSMAD2 2 hours after irradiation, and 95% 4 hours after irradiation, compared with matched controls. High-fluence light-emitting diode red light resulted in no significant difference in transforming growth factor-beta receptor I levels compared with matched controls. Skin fibrosis is a significant medical problem with limited available treatment modalities. Light-emitting diode-generated red light is a safe, economic, and noninvasive modality that has a body of in vitro evidence supporting the reduction of key cellular characteristics associated with skin fibrosis.

Combustion Of Interacting Droplet Arrays In Microgravity

NASA Technical Reports Server (NTRS)

Dietrich, D. L.; Struk, P. M.; Ikegami, M.; Xu, G.

2003-01-01

Theory and experiments involving single droplet combustion date back to 1953, with the first microgravity work appearing in 1956. The problem of a spherical droplet burning in an infinite, quiescent microgravity environment is a classical problem in combustion research with the classical solution appearing in nearly every textbook on combustion. The microgravity environment offered by ground-based facilities such as drop towers and space-based facilities is ideal for studying the problem experimentally. A recent review by Choi and Dryer shows significant advances in droplet combustion have been made by studying the problem experimentally in microgravity and comparing the results to one dimensional theoretical and numerical treatments of the problem. Studying small numbers of interacting droplets in a well-controlled geometry represents a logical step in extending single droplet investigations to more practical spray configurations. Studies of droplet interactions date back to Rex and co-workers, and were recently summarized by Annamalai and Ryan. All previous studies determined the change in the burning rate constant, k, or the flame characteristics as a result of interactions. There exists almost no information on how droplet interactions a effect extinction limits, and if the extinction limits change if the array is in the diffusive or the radiative extinction regime. Thus, this study examined experimentally the effect that droplet interactions have on the extinction process by investigating the simplest array configuration, a binary droplet array. The studies were both in normal gravity, reduced pressure ambients and microgravity facilities. The microgravity facilities were the 2.2 and 5.2 second drop towers at the NASA Glenn Research Center and the 10 second drop tower at the Japan Microgravity Center. The experimental apparatus and the data analysis techniques are discussed in detail elsewhere.

Teaching and evaluating critical thinking in respiratory care.

PubMed

Mishoe, Shelley C; Hernlen, Kitty

2005-09-01

The capacity to perform critical thinking in respiratory care may be enhanced through awareness and education to improve skills, abilities, and opportunities. The essential skills for critical thinking in respiratory care include prioritizing, anticipating, troubleshooting, communicating, negotiating, decision making, and reflecting. In addition to these skills, critical thinkers exhibit certain characteristics such as critical evaluation, judgment,insight, motivation, and lifelong learning. The teaching of critical thinking may be accomplished though problem-based learning using an evidenced-based approach to solve clinical problems similar to those encountered in professional practice. Other traditional strategies such as discussion, debate, case study, and case presentations can be used. Web-based curriculum and technologic advances have created opportunities such as bulletin boards, real-time chats, and interactive media tools that can incorporate critical thinking. Many concerns and controversies surround the assessment of critical thinking, and individuals who administer critical thinking tests must be aware of the strengths and limitations of these assessment tools, as well as their relevance to the workplace. The foundational works reported in this article summarize the current status of assessment of critical thinking and can stimulate further investigation and application of the skills, characteristics, educational strategies, and measurement of critical thinking in respiratory care.

An iterative transformation procedure for numerical solution of flutter and similar characteristics-value problems

NASA Technical Reports Server (NTRS)

Gossard, Myron L

1952-01-01

An iterative transformation procedure suggested by H. Wielandt for numerical solution of flutter and similar characteristic-value problems is presented. Application of this procedure to ordinary natural-vibration problems and to flutter problems is shown by numerical examples. Comparisons of computed results with experimental values and with results obtained by other methods of analysis are made.

An effective pseudospectral method for constraint dynamic optimisation problems with characteristic times

NASA Astrophysics Data System (ADS)

Xiao, Long; Liu, Xinggao; Ma, Liang; Zhang, Zeyin

2018-03-01

Dynamic optimisation problem with characteristic times, widely existing in many areas, is one of the frontiers and hotspots of dynamic optimisation researches. This paper considers a class of dynamic optimisation problems with constraints that depend on the interior points either fixed or variable, where a novel direct pseudospectral method using Legendre-Gauss (LG) collocation points for solving these problems is presented. The formula for the state at the terminal time of each subdomain is derived, which results in a linear combination of the state at the LG points in the subdomains so as to avoid the complex nonlinear integral. The sensitivities of the state at the collocation points with respect to the variable characteristic times are derived to improve the efficiency of the method. Three well-known characteristic time dynamic optimisation problems are solved and compared in detail among the reported literature methods. The research results show the effectiveness of the proposed method.

Massively Scalable Near Duplicate Detection in Streams of Documents using MDSH

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

Bogen, Paul Logasa; Symons, Christopher T; McKenzie, Amber T

2013-01-01

In a world where large-scale text collections are not only becoming ubiquitous but also are growing at increasing rates, near duplicate documents are becoming a growing concern that has the potential to hinder many different information filtering tasks. While others have tried to address this problem, prior techniques have only been used on limited collection sizes and static cases. We will briefly describe the problem in the context of Open Source Intelligence (OSINT) along with our additional constraints for performance. In this work we propose two variations on Multi-dimensional Spectral Hash (MDSH) tailored for working on extremely large, growing setsmore » of text documents. We analyze the memory and runtime characteristics of our techniques and provide an informal analysis of the quality of the near-duplicate clusters produced by our techniques.« less

The Study of CIQ Inspection Rate's Setting Problem Based on Gray-fuzzy Comprehensive Evaluation Theory

NASA Astrophysics Data System (ADS)

Hui, Liu; Ding, Liu Wen

Inspection is not only one of the most significant duties, but the important prerequisite for going through Customs. Setting the inspection rate scientifically can not only solve the contradiction between the "check on" and "service" for CIQ (CHINA ENTRY-EXIT INSPECTION AND UARANTINE)site inspection personnel, but can highlight the key of inspection and enhance the ratio of discovering, achieving the optimum allocation of CIQ's limited human and material resources. In this article, from the characteristics of inspection risk evaluation themselves, considering the setting problem of check rate at from the angle of data mining, construct an index system rationally and objectively. On the basis of Fuzzy theory, evaluate the risk of the inward and outward goods with the grey-fuzzy comprehensive evaluation method, and establish the inspection rate scientifically.

The correlation of pain intensity and quality of life in chronic LBP patients in Adam Malik general hospital

NASA Astrophysics Data System (ADS)

Nasution, I. K.; Lubis, N. D. A.; Amelia, S.; Hocin, K.

2018-03-01

Low back pain (LBP) is a world health problems and a major cause of disability. The study is to determine the correlation between pain intensity and quality of life (QoL) in patients with chronic LBP. This study was a descriptive, analytical research with the cross sectional design. Twenty-nine chronic LBP outpatients that have visited the Neurology Clinic of Adam Malik General Hospital Medan. Patients from July to November 2015 were selected by consecutive sampling. A questionnaire and interview are asking the information about subjects’ characteristics, diagnosis, medical history, pain intensity and quality of life-based on WHO QoL criteria were used to collect the data. Using Spearman correlation test, we found correlation among VAS and physical function (p<0.001, r=-0.606), limitations due to physical problems (p<0.001, r=-0.837), limitations due to emotional problems (p=0.007, r=-0,477), vitality (p=0.021, r=-0.380), social function (p=0.015, r=-0.403), the feeling of pain (p=0.003, r=-0.499) and general health (p=0.040, r=-0.330). On the other hand, there was no correlation between VAS and mental health (p=0.110, r=-0.235). We concluded that pain intensity in outpatients with chronic LBP in the Neurology Clinic at Adam Malik General Hospital Medan correlates with the patients’ quality of life.

On line separation of overlapped signals from multi-time photons for the GEM-based detection system

NASA Astrophysics Data System (ADS)

Czarski, T.; Pozniak, K. T.; Chernyshova, M.; Malinowski, K.; Kasprowicz, G.; Kolasinski, P.; Krawczyk, R.; Wojenski, A.; Zabolotny, W.

2015-09-01

The Triple Gas Electron Multiplier (T-GEM) is presented as soft X-ray (SXR) energy and position sensitive detector for high-resolution X-ray diagnostics of magnetic confinement fusion plasmas. Multi-channel measurement system and serial data acquisition for X-ray energy and position recognition is described. Fundamental characteristics are presented for two dimensional detector structure. Typical signals of ADC - Analog to Digital Converter are considered for charge value and position estimation. Coinciding signals for high flux radiation cause the problem for cluster charge identification. The amplifier with shaper determines time characteristics and limits the pulses frequency. Separation of coincided signals was introduced and verified for simulation experiments. On line separation of overlapped signals was implemented applying the FPGA technology with relatively simple firmware procedure. Representative results for reconstruction of coinciding signals are demonstrated.

Elastic model of the traction behavior of two traction lubricants

NASA Technical Reports Server (NTRS)

Loewenthal, S. H.; Rohn, D. A.

1984-01-01

In the analysis of rolling-sliding concentrated contacts, such as gears, bearings and traction drives, the traction characteristics of the lubricant are of prime importance. The elastic shear modulus and limiting shear stress properties of the lubricant dictate the traction/slip characteristics and power loss associated with an EHD contact undergoing slip and/or spin. These properties can be deducted directly from the initial slope m and maximum traction coefficient micron of an experimental traction curve. In this investigation, correlation equations are presented to predict m and micron for two modern traction fluids based on the regression analysis of 334 separate traction disk machine experiments. The effects of contact pressure, temperature, surface velocity, ellipticity ratio are examined. Problems in deducing lubricant shear moduli from disk machine tests are discussed. Previously announced in STAR as N83-20116

Comparison of self-reported and audiometrically-measured hearing loss in the Australian Defence Force.

PubMed

Kirk, Katherine M; McGuire, Annabel; Nasveld, Peter E; Treloar, Susan A

2012-04-01

To investigate the relationship between self-reported and audiometrically-measured hearing loss in a sample of Australian Defence Force personnel. Responses to a question regarding hearing problems were compared with contemporaneous audiometric data. 3335 members of the Australian Defence Force for whom anonymised medical records were available. The sensitivity of self-report data to identify higher-frequency hearing loss was lower than sensitivity at other frequencies, and positive predictive values were moderate to poor at all frequencies. Performance characteristics of self-report compared with audiometric data also varied with age, sex, and rank. While self-report hearing loss data have good performance characteristics for estimating prevalence of hearing loss as defined by audiometric criteria, this study indicates that the usefulness of self-report data in identifying individuals with hearing loss may be limited in this population.

Computer re-sampling for demographically representative user populations in anthropometry: a case of doorway and clear floor space widths.

PubMed

Paquet, Victor; Joseph, Caroline; D'Souza, Clive

2012-01-01

Anthropometric studies typically require a large number of individuals that are selected in a manner so that demographic characteristics that impact body size and function are proportionally representative of a user population. This sampling approach does not allow for an efficient characterization of the distribution of body sizes and functions of sub-groups within a population and the demographic characteristics of user populations can often change with time, limiting the application of the anthropometric data in design. The objective of this study is to demonstrate how demographically representative user populations can be developed from samples that are not proportionally representative in order to improve the application of anthropometric data in design. An engineering anthropometry problem of door width and clear floor space width is used to illustrate the value of the approach.

Teacher Perceptions and Behavioral Strategies for Students with Emotional Disturbance across Educational Environments

ERIC Educational Resources Information Center

Evans, Chan; Weiss, Stacy L.; Cullinan, Douglas

2012-01-01

The present study examined problem characteristics of students with emotional disturbance in 3 educational environments, the behavior management and intervention strategies their teachers used, and what relation exists between problem characteristics and intervention strategies. Teachers completed a behavior problems rating scale and they…

Social problem-solving abilities and personality disorder characteristics among dual-diagnosed persons in substance abuse treatment.

PubMed

Herrick, S M; Elliott, T R

2001-01-01

We examined the relation of self-appraised social problem-solving abilities and personality-disorder characteristics to the adjustment and compliance of persons with dual diagnoses in substance-abuse treatment. It was hypothesized that elements of the problem-orientation component would remain predictive of depressive behavior and distress after considering personality-disorder characteristics among 117 persons receiving inpatient-substance-abuse treatment. Furthermore, self-appraised problem-solving abilities were expected to predict the occurrence of "dirty" drug and alcohol screens during treatment and compliance with the first scheduled community follow-up visit. Results supported predictions concerning the relation of problem-solving confidence to depressive behavior, distress, and substance-use screens; however, a paradoxical relation was observed between the problem-orientation variables and compliance with the first outpatient visit. The results are interpreted within the context of contemporary models of social problem solving and the implications for cognitive-behavioral assessment and intervention are considered.

On the characteristic exponents of the general three-body problem

NASA Technical Reports Server (NTRS)

Broucke, R.

1976-01-01

A description is given of some properties of the characteristic exponents of the general three-body problem. The variational equations on which the analysis is based are obtained by linearizing the Lagrangian equations of motion in the neighborhood of a given known solution. Attention is given to the fundamental matrix of solutions, the characteristic equation, the three trivial solutions of the variational equations of the three-body problem, symmetric periodic orbits, and the half-period properties of symmetric periodic orbits.

Limitations of and Barriers to Using Performance Measurement: Purchasers' Perspectives

PubMed Central

Ginsberg, Caren; Sheridan, Samantha

2001-01-01

Although health plan performance data are becoming increasingly more available, many purchasers are still not using these data to make their purchasing decisions. In this article, we review barriers that private purchasers face to using performance data. In addition, we consider the effects of the larger health care purchasing environment and employers' quality improvement activities on their use of the data. We conclude that a variety of factors, including trends, the health care purchasing environment, characteristics of firms, and problems with performance data and their presentation to users create barriers to incorporating this information into health care decisionmaking. PMID:25372184

Analytical and simulator study of advanced transport

NASA Technical Reports Server (NTRS)

Levison, W. H.; Rickard, W. W.

1982-01-01

An analytic methodology, based on the optimal-control pilot model, was demonstrated for assessing longitidunal-axis handling qualities of transport aircraft in final approach. Calibration of the methodology is largely in terms of closed-loop performance requirements, rather than specific vehicle response characteristics, and is based on a combination of published criteria, pilot preferences, physical limitations, and engineering judgment. Six longitudinal-axis approach configurations were studied covering a range of handling qualities problems, including the presence of flexible aircraft modes. The analytical procedure was used to obtain predictions of Cooper-Harper ratings, a solar quadratic performance index, and rms excursions of important system variables.

Almucantar radio telescope report 1: A preliminary study of the capabilities of large partially steerable paraboloidal antennas

NASA Technical Reports Server (NTRS)

Usher, P. D.

1971-01-01

The almucantar radio telescope development and characteristics are presented. The radio telescope consists of a paraboloidal reflector free to rotate in azimuth but limited in altitude between two fixed angles from the zenith. The fixed angles are designed to provide the capability where sources lying between two small circles parallel with the horizon (almucantars) are accessible at any one instant. Basic geometrical considerations in the almucantar design are presented. The capabilities of the almucantar telescope for source counting and for monitoring which are essential to a resolution of the cosmological problem are described.

The energy balance of wind waves and the remote sensing problem

NASA Technical Reports Server (NTRS)

Hasselmann, K.

1972-01-01

Measurements of wave growth indicate an energy balance of the wave spectrum governed primarily by input from the atmosphere, nonlinear transfer to shorter and longer waves, and advection. The pronounced spectral peak and sharp low frequency cut-off characteristic of fetch-limited spectra are explained as a self-stabilizing feature of the nonlinear wave-wave interactions. The momentum transferred from the atmosphere to the wind waves accounts for a large part of the wind drag. These findings are relevant for remote microwave sensing of the sea surface by backscatter and passive radiometry methods.

Application of Artificial Neural Networks to the Design of Turbomachinery Airfoils

NASA Technical Reports Server (NTRS)

Rai, Man Mohan; Madavan, Nateri

1997-01-01

Artificial neural networks are widely used in engineering applications, such as control, pattern recognition, plant modeling and condition monitoring to name just a few. In this seminar we will explore the possibility of applying neural networks to aerodynamic design, in particular, the design of turbomachinery airfoils. The principle idea behind this effort is to represent the design space using a neural network (within some parameter limits), and then to employ an optimization procedure to search this space for a solution that exhibits optimal performance characteristics. Results obtained for design problems in two spatial dimensions will be presented.

The optimization of nuclear power plants operation modes in emergency situations

NASA Astrophysics Data System (ADS)

Zagrebayev, A. M.; Trifonenkov, A. V.; Ramazanov, R. N.

2018-01-01

An emergency situations resulting in the necessity for temporary reactor trip may occur at the nuclear power plant while normal operating mode. The paper deals with some of the operation c aspects of nuclear power plant operation in emergency situations and during threatened period. The xenon poisoning causes limitations on the variety of statements of the problem of calculating characteristics of a set of optimal reactor power off controls. The article show a possibility and feasibility of new sets of optimization tasks for the operation of nuclear power plants under conditions of xenon poisoning in emergency circumstances.

Analysis of limiting information characteristics of quantum-cryptography protocols

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

Sych, D V; Grishanin, Boris A; Zadkov, Viktor N

2005-01-31

The problem of increasing the critical error rate of quantum-cryptography protocols by varying a set of letters in a quantum alphabet for space of a fixed dimensionality is studied. Quantum alphabets forming regular polyhedra on the Bloch sphere and the continual alphabet equally including all the quantum states are considered. It is shown that, in the absence of basis reconciliation, a protocol with the tetrahedral alphabet has the highest critical error rate among the protocols considered, while after the basis reconciliation, a protocol with the continual alphabet possesses the highest critical error rate. (quantum optics and quantum computation)

Psychometric properties of the Brand Personality Scale: evidence from a business school.

PubMed

Caruana, Albert; Pitt, Leyland F; Berthon, Pierre; Berthon, J-P

2007-06-01

The Brand Personality Scale has received considerable attention and has been frequently used and cited in the branding literature. This paper describes an investigation of the psychometric characteristics of the Brand Personality Scale in a business school context where umbrella branding is used. A sample (N=262) of students attending the MBA program of a major business school in eastern USA completed the scale. Results indicate problems with the scale's dimensionality, poor reliability, convergent and nomological validity of the Ruggedness dimension, and lack of support for discriminant validity. Managerial and research implications and limitations are noted.

Stressed Ge:Ga photoconductors for space-based astronomy. (Is there life beyond 120 micron)

NASA Technical Reports Server (NTRS)

Beeman, J. W.; Haller, E. E.; Hansen, W. L.; Luke, P. N.; Richards, P. L.

1989-01-01

Information is given in viewgraph form. Information is given on the characteristics of stressed Ge:Ga, a spring type stress cavity, mounting hardware, materials parameters affecting dark current, and the behavior of low dark current stressed Ge:Ga. It is concluded that detectors exist today for background-limited detection at 200 microns, that researchers are narrowing in on the significant parameters that effect dark current in stressed photoconductors, that these findings may be applied to other photoconductor materials, and that some creative problem solving for an ionizing effect reset mechanism is needed.

Adolescent mental health and earnings inequalities in adulthood: evidence from the Young-HUNT Study.

PubMed

Evensen, Miriam; Lyngstad, Torkild Hovde; Melkevik, Ole; Reneflot, Anne; Mykletun, Arnstein

2017-02-01

Previous studies have shown that adolescent mental health problems are associated with lower employment probabilities and risk of unemployment. The evidence on how earnings are affected is much weaker, and few have addressed whether any association reflects unobserved characteristics and whether the consequences of mental health problems vary across the earnings distribution. A population-based Norwegian health survey linked to administrative registry data (N=7885) was used to estimate how adolescents' mental health problems (separate indicators of internalising, conduct, and attention problems and total sum scores) affect earnings (≥30 years) in young adulthood. We used linear regression with fixed-effects models comparing either students within schools or siblings within families. Unconditional quantile regressions were used to explore differentials across the earnings distribution. Mental health problems in adolescence reduce average earnings in adulthood, and associations are robust to control for observed family background and school fixed effects. For some, but not all mental health problems, associations are also robust in sibling fixed-effects models, where all stable family factors are controlled. Further, we found much larger earnings loss below the 25th centile. Adolescent mental health problems reduce adult earnings, especially among individuals in the lower tail of the earnings distribution. Preventing mental health problems in adolescence may increase future earnings. 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/.

A large-scale national study of gambling severity among immigrant and non-immigrant adolescents: The role of the family.

PubMed

Canale, Natale; Vieno, Alessio; Griffiths, Mark D; Borraccino, Alberto; Lazzeri, Giacomo; Charrier, Lorena; Lemma, Patrizia; Dalmasso, Paola; Santinello, Massimo

2017-03-01

The primary aim of the present study was to examine the association between immigrant generation, family sociodemographic characteristics, and problem gambling severity in a large-scale nationally representative sample of Italian youth. Data from the 2013-2014 Health Behaviour in School-aged Children (HBSC) Survey were used for cross-sectional analyses of adolescent problem gambling. Self-administered questionnaires were completed by a representative sample of 20,791 15-year-old students. Respondents' problem gambling severity, immigrant status, family characteristics (family structure, family affluence, perceived family support) and socio-demographic characteristics were individually assessed. Rates of adolescent at-risk/problem gambling were twice as high among first generation immigrants than non-immigrant students; the odds of being at-risk/problem gamblers were higher among first-generation immigrants than adolescents of other immigrant generations or non-immigrant. Not living with two biological or adoptive parents appears to be a factor that increases the risk of becoming a problem gambler in first generation immigrants. Immigrant status and family characteristics may play a key role in contributing to adolescent problem gambling. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

A Semi-implicit Method for Resolution of Acoustic Waves in Low Mach Number Flows

NASA Astrophysics Data System (ADS)

Wall, Clifton; Pierce, Charles D.; Moin, Parviz

2002-09-01

A semi-implicit numerical method for time accurate simulation of compressible flow is presented. By extending the low Mach number pressure correction method, a Helmholtz equation for pressure is obtained in the case of compressible flow. The method avoids the acoustic CFL limitation, allowing a time step restricted only by the convective velocity, resulting in significant efficiency gains. Use of a discretization that is centered in both time and space results in zero artificial damping of acoustic waves. The method is attractive for problems in which Mach numbers are low, and the acoustic waves of most interest are those having low frequency, such as acoustic combustion instabilities. Both of these characteristics suggest the use of time steps larger than those allowable by an acoustic CFL limitation. In some cases it may be desirable to include a small amount of numerical dissipation to eliminate oscillations due to small-wavelength, high-frequency, acoustic modes, which are not of interest; therefore, a provision for doing this in a controlled manner is included in the method. Results of the method for several model problems are presented, and the performance of the method in a large eddy simulation is examined.

Analysis and design of numerical schemes for gas dynamics 1: Artificial diffusion, upwind biasing, limiters and their effect on accuracy and multigrid convergence

NASA Technical Reports Server (NTRS)

Jameson, Antony

1994-01-01

The theory of non-oscillatory scalar schemes is developed in this paper in terms of the local extremum diminishing (LED) principle that maxima should not increase and minima should not decrease. This principle can be used for multi-dimensional problems on both structured and unstructured meshes, while it is equivalent to the total variation diminishing (TVD) principle for one-dimensional problems. A new formulation of symmetric limited positive (SLIP) schemes is presented, which can be generalized to produce schemes with arbitrary high order of accuracy in regions where the solution contains no extrema, and which can also be implemented on multi-dimensional unstructured meshes. Systems of equations lead to waves traveling with distinct speeds and possibly in opposite directions. Alternative treatments using characteristic splitting and scalar diffusive fluxes are examined, together with modification of the scalar diffusion through the addition of pressure differences to the momentum equations to produce full upwinding in supersonic flow. This convective upwind and split pressure (CUSP) scheme exhibits very rapid convergence in multigrid calculations of transonic flow, and provides excellent shock resolution at very high Mach numbers.

An Effective and Robust Decentralized Target Tracking Scheme in Wireless Camera Sensor Networks.

PubMed

Fu, Pengcheng; Cheng, Yongbo; Tang, Hongying; Li, Baoqing; Pei, Jun; Yuan, Xiaobing

2017-03-20

In this paper, we propose an effective and robust decentralized tracking scheme based on the square root cubature information filter (SRCIF) to balance the energy consumption and tracking accuracy in wireless camera sensor networks (WCNs). More specifically, regarding the characteristics and constraints of camera nodes in WCNs, some special mechanisms are put forward and integrated in this tracking scheme. First, a decentralized tracking approach is adopted so that the tracking can be implemented energy-efficiently and steadily. Subsequently, task cluster nodes are dynamically selected by adopting a greedy on-line decision approach based on the defined contribution decision (CD) considering the limited energy of camera nodes. Additionally, we design an efficient cluster head (CH) selection mechanism that casts such selection problem as an optimization problem based on the remaining energy and distance-to-target. Finally, we also perform analysis on the target detection probability when selecting the task cluster nodes and their CH, owing to the directional sensing and observation limitations in field of view (FOV) of camera nodes in WCNs. From simulation results, the proposed tracking scheme shows an obvious improvement in balancing the energy consumption and tracking accuracy over the existing methods.

An Effective and Robust Decentralized Target Tracking Scheme in Wireless Camera Sensor Networks

PubMed Central

Fu, Pengcheng; Cheng, Yongbo; Tang, Hongying; Li, Baoqing; Pei, Jun; Yuan, Xiaobing

2017-01-01

In this paper, we propose an effective and robust decentralized tracking scheme based on the square root cubature information filter (SRCIF) to balance the energy consumption and tracking accuracy in wireless camera sensor networks (WCNs). More specifically, regarding the characteristics and constraints of camera nodes in WCNs, some special mechanisms are put forward and integrated in this tracking scheme. First, a decentralized tracking approach is adopted so that the tracking can be implemented energy-efficiently and steadily. Subsequently, task cluster nodes are dynamically selected by adopting a greedy on-line decision approach based on the defined contribution decision (CD) considering the limited energy of camera nodes. Additionally, we design an efficient cluster head (CH) selection mechanism that casts such selection problem as an optimization problem based on the remaining energy and distance-to-target. Finally, we also perform analysis on the target detection probability when selecting the task cluster nodes and their CH, owing to the directional sensing and observation limitations in field of view (FOV) of camera nodes in WCNs. From simulation results, the proposed tracking scheme shows an obvious improvement in balancing the energy consumption and tracking accuracy over the existing methods. PMID:28335537

Identification of potent biodegradable adjuvants that efficiently break self-tolerance--a key issue in the development of therapeutic vaccines.

PubMed

Ringvall, Maria; Huijbers, Elisabeth J M; Ahooghalandari, Parvin; Alekseeva, Ludmila; Andronova, Tatyana; Olsson, Anna-Karin; Hellman, Lars

2009-12-10

Monoclonal antibodies are used successfully in the treatment of many human disorders. However, these antibodies are expensive and have in many countries put a major strain on the health care economy. Therapeutic vaccines, directed against the same target molecules, may offer a solution to this problem. Vaccines usually involve lower amount of recombinant protein, approximately 10,000-20,000 times less, which is significantly more cost effective. Attempts to develop such therapeutic vaccines have also been made. However, their efficacy has been limited by the lack of potent immunostimulatory compounds, adjuvants, for human use. To address this problem we have conducted a broad screening for adjuvants that can enhance the efficacy of therapeutic vaccines, whilst at the same time being non-toxic and biodegradable. We have now identified adjuvants that show these desired characteristics. A combination of Montanide ISA720 and phosphorothioate stabilized CpG stimulatory DNA, induced similar or even higher anti-self-antibody titers compared to Freund's adjuvant, currently the most potent, but also toxic, adjuvant available. This finding removes one of the major limiting factors in the field and facilitates the development of a broad range of novel therapeutic vaccines.

Rating Students' Problem Behaviour: The Role of Teachers' Individual Characteristics

ERIC Educational Resources Information Center

Kokkinos, Constantinos M.; Kargiotidis, Apostolos

2016-01-01

This study examined the role of teachers' personal characteristics and mental health status on their frequency ratings of student problem behaviour. A sample of 121 primary school teachers were asked to rate the frequency of a student's behavioural problems, and to self-report their personality traits, psychopathology symptoms and burnout.…

Parenting and Children's Adjustment Problems: The Mediating Role of Self-Esteem and Peer Relations

ERIC Educational Resources Information Center

Georgiou, Nicos A.; Stavrinides, Panayiotis; Georgiou, Stelios

2016-01-01

The aim of this study was to investigate the impact of parental and personal characteristics on children's internalizing/externalizing problems. Further, this study aimed to examine personal characteristics (self-esteem, peer relations) as mediators in the relation between parenting and internalizing/externalizing problems. In order to address…

[Executive functions and stressful characteristics of children with attention-deficit hyperactivity disorder: influence on behavioral problems during adolescence].

PubMed

Colomer-Diago, Carla; Miranda-Casas, Ana; Herdoiza-Arroyo, Paulina; Presentación-Herrero, M Jesús

2012-02-29

The identification of possible factors that are influencing the course of attention-deficit hyperactivity disorder (ADHD) will allow the development of more effective early intervention strategies. AIMS. This research, which used a longitudinal and correlational design, set out to examine the temporal consistency of the primary symptoms and ADHD associated problems. In addition, the relationships and predictive power of working memory, inhibition and stressful characteristics of children with ADHD on the disorder symptoms and behavioral problems in adolescence was analyzed. This study included 65 families with children diagnosed with ADHD. In phase 1 children performed verbal working memory, visuo-spatial and inhibition tests, and information from parents about stressful characteristics of children was collected. In phase 1 and in the follow-up phase, which took place three years later, parents and teachers reported on the primary symptoms of ADHD and behavioral problems. Inattention symptoms as well as most behavioral problems were stable over time, while hyperactivity/impulsivity symptoms decreased. Moreover, neither working memory nor inhibition showed power to predict the central manifestations of ADHD or behavioral problems, while stressful characteristics of demandingness, low adaptability and negative mood had a moderate predictive capacity. These results confirm the role of stressful child characteristics as a risk factor in the course of ADHD.

Normativity and Desirability in Observational Assessments of Family Interaction.

PubMed

Deal, James E

2018-06-11

Issues of normativity (responding in a typical or average fashion) and desirability (the tendency for raters to endorse positive characteristics rather than neutral or more negative ones) are common in areas of the social sciences that frequently utilize profile correlations to measure dyadic similarity. They have implications for family scholars as well. In the present study, a pre-existing data set was used to make an initial, though limited, investigation into potential confounds of normativity and desirability for macrolevel observational assessments of family interaction. An empirical example is presented using q-sort ratings of family interaction, with variance in observational assessments decomposed into component parts. High levels of both normativity and desirability were found, indicating possible problems in terms of both reliability and validity of assessment. While the results provide an interesting beginning, they are limited due to the use of a q-sort methodology as well as an instrument with limited background and use. These limitations are discussed, as well as alternative interpretations for normativity and desirability and implications for future research. © 2018 Family Process Institute.

Physicochemical Characteristics of Dust Particles in HVOF Spraying and Occupational Hazards: Case Study in a Chinese Company

NASA Astrophysics Data System (ADS)

Huang, Haihong; Li, Haijun; Li, Xinyu

2016-06-01

Dust particles generated in thermal spray process can cause serious health problems to the workers. Dust particles generated in high velocity oxy-fuel (HVOF) spraying WC-Co coatings were characterized in terms of mass concentrations, particle size distribution, micro morphologies, and composition. Results show that the highest instantaneous exposure concentration of dust particles in the investigated thermal spray workshop is 140 mg/m3 and the time-weighted average concentration is 34.2 mg/m3, which are approximately 8 and 4 times higher than the occupational exposure limits in China, respectively. The large dust particles above 10 μm in size present a unique morphology of polygonal or irregular block of crushed powder, and smaller dust particles mainly exist in the form of irregular or flocculent agglomerates. Some heavy metals, such as chromium, cobalt, and nickel, are also found in the air of the workshop and their concentrations are higher than the limits. Potential occupational hazards of the dust particles in the thermal spray process are further analyzed based on their characteristics and the workers' exposure to the nanoparticles is assessed using a control banding tool.

Pre-Proposal Assessment of Reliability for Spacecraft Docking with Limited Information

NASA Technical Reports Server (NTRS)

Brall, Aron

2013-01-01

This paper addresses the problem of estimating the reliability of a critical system function as well as its impact on the system reliability when limited information is available. The approach addresses the basic function reliability, and then the impact of multiple attempts to accomplish the function. The dependence of subsequent attempts on prior failure to accomplish the function is also addressed. The autonomous docking of two spacecraft was the specific example that generated the inquiry, and the resultant impact on total reliability generated substantial interest in presenting the results due to the relative insensitivity of overall performance to basic function reliability and moderate degradation given sufficient attempts to try and accomplish the required goal. The application of the methodology allows proper emphasis on the characteristics that can be estimated with some knowledge, and to insulate the integrity of the design from those characteristics that can't be properly estimated with any rational value of uncertainty. The nature of NASA's missions contains a great deal of uncertainty due to the pursuit of new science or operations. This approach can be applied to any function where multiple attempts at success, with or without degradation, are allowed.

Testing Scientific Software: A Systematic Literature Review

PubMed Central

Kanewala, Upulee; Bieman, James M.

2014-01-01

Context Scientific software plays an important role in critical decision making, for example making weather predictions based on climate models, and computation of evidence for research publications. Recently, scientists have had to retract publications due to errors caused by software faults. Systematic testing can identify such faults in code. Objective This study aims to identify specific challenges, proposed solutions, and unsolved problems faced when testing scientific software. Method We conducted a systematic literature survey to identify and analyze relevant literature. We identified 62 studies that provided relevant information about testing scientific software. Results We found that challenges faced when testing scientific software fall into two main categories: (1) testing challenges that occur due to characteristics of scientific software such as oracle problems and (2) testing challenges that occur due to cultural differences between scientists and the software engineering community such as viewing the code and the model that it implements as inseparable entities. In addition, we identified methods to potentially overcome these challenges and their limitations. Finally we describe unsolved challenges and how software engineering researchers and practitioners can help to overcome them. Conclusions Scientific software presents special challenges for testing. Specifically, cultural differences between scientist developers and software engineers, along with the characteristics of the scientific software make testing more difficult. Existing techniques such as code clone detection can help to improve the testing process. Software engineers should consider special challenges posed by scientific software such as oracle problems when developing testing techniques. PMID:25125798

HERO - A 3D general relativistic radiative post-processor for accretion discs around black holes

NASA Astrophysics Data System (ADS)

Zhu, Yucong; Narayan, Ramesh; Sadowski, Aleksander; Psaltis, Dimitrios

2015-08-01

HERO (Hybrid Evaluator for Radiative Objects) is a 3D general relativistic radiative transfer code which has been tailored to the problem of analysing radiation from simulations of relativistic accretion discs around black holes. HERO is designed to be used as a post-processor. Given some fixed fluid structure for the disc (i.e. density and velocity as a function of position from a hydrodynamic or magnetohydrodynamic simulation), the code obtains a self-consistent solution for the radiation field and for the gas temperatures using the condition of radiative equilibrium. The novel aspect of HERO is that it combines two techniques: (1) a short-characteristics (SC) solver that quickly converges to a self-consistent disc temperature and radiation field, with (2) a long-characteristics (LC) solver that provides a more accurate solution for the radiation near the photosphere and in the optically thin regions. By combining these two techniques, we gain both the computational speed of SC and the high accuracy of LC. We present tests of HERO on a range of 1D, 2D, and 3D problems in flat space and show that the results agree well with both analytical and benchmark solutions. We also test the ability of the code to handle relativistic problems in curved space. Finally, we discuss the important topic of ray defects, a major limitation of the SC method, and describe our strategy for minimizing the induced error.

Youth with chronic health problems: how do they fare in main-stream mentoring programs?

PubMed

Lipman, Ellen L; DeWit, David; DuBois, David L; Larose, Simon; Erdem, Gizem

2018-01-05

Youth with chronic physical health problems often experience social and emotional problems. We investigate the relationship between participation in the Big Brothers Big Sisters of Canada community-based mentoring programs (BBBS) and youth social and mood outcomes by youth health status. Youth newly enrolled in BBBS were classified by health status (one or more chronic physical health problems without activity limitation, n = 191; one or more chronic physical health problems with activity limitation, n = 94; no chronic health problem or activity limitation, n = 536) and mentoring status (yes/no) at 18 month follow-up. Youth outcomes measured at follow-up were social anxiety, depressed mood, and peer self-esteem. Youth with chronic health problems and activity limitation were more likely to live with two biological parents, use mental health or social services, and have parents who reported difficulties with depressed mood, social anxiety, family functioning and neighbourhood problems. At 18 month follow-up, mentored youth in this health status group experienced fewer symptoms of social anxiety and higher peer self-esteem compared to non-mentored youth. Mentored youth with chronic health problems without activity limitation and mentored youth with no health problems or limitations did not show significant improvements in social anxiety and peer self-esteem. Regardless of their health status, mentored youth reported fewer symptoms of depressed mood than non-mentored youth. Youth with chronic health problems, particularly those with activity limitation as well, demonstrate a capacity to experience social and mood benefits associated with mentoring.

Robust Feedback Control of Flow Induced Structural Radiation of Sound

NASA Technical Reports Server (NTRS)

Heatwole, Craig M.; Bernhard, Robert J.; Franchek, Matthew A.

1997-01-01

A significant component of the interior noise of aircraft and automobiles is a result of turbulent boundary layer excitation of the vehicular structure. In this work, active robust feedback control of the noise due to this non-predictable excitation is investigated. Both an analytical model and experimental investigations are used to determine the characteristics of the flow induced structural sound radiation problem. The problem is shown to be broadband in nature with large system uncertainties associated with the various operating conditions. Furthermore the delay associated with sound propagation is shown to restrict the use of microphone feedback. The state of the art control methodologies, IL synthesis and adaptive feedback control, are evaluated and shown to have limited success for solving this problem. A robust frequency domain controller design methodology is developed for the problem of sound radiated from turbulent flow driven plates. The control design methodology uses frequency domain sequential loop shaping techniques. System uncertainty, sound pressure level reduction performance, and actuator constraints are included in the design process. Using this design method, phase lag was added using non-minimum phase zeros such that the beneficial plant dynamics could be used. This general control approach has application to lightly damped vibration and sound radiation problems where there are high bandwidth control objectives requiring a low controller DC gain and controller order.

Experimental investigation of wing installation effects on a two-dimensional mixer/ejector nozzle for supersonic transport aircraft

NASA Technical Reports Server (NTRS)

Anderson, David J.; Lambert, Heather H.; Mizukami, Masashi

1992-01-01

Experimental results from a wind tunnel test conducted to investigate propulsion/airframe integration (PAI) effects are presented. The objectives of the test were to examine rough order-of-magnitude changes in the acoustic characteristics of a mixer/ejector nozzle due to the presence of a wing and to obtain limited wing and nozzle flow-field measurements. A simple representative supersonic transport wing planform, with deflecting flaps, was installed above a two-dimensional mixer/ejector nozzle that was supplied with high-pressure heated air. Various configurations and wing positions with respect to the nozzle were studied. Because of hardware problems, no acoustics and only a limited set of flow-field data were obtained. For most hardware configurations tested, no significant propulsion/airframe integration effects were identified. Significant effects were seen for extreme flap deflections. The combination of the exploratory nature of the test and the limited flow-field instrumentation made it impossible to identify definitive propulsion/airframe integration effects.

Obesity Prevention in the Military.

PubMed

Shams-White, Marissa; Deuster, Patricia

2017-06-01

The objective was to review prevention efforts and approaches attempting to limit the problem of obesity in the military. Various individual-level initiatives have emerged, including programs promoting healthy cooking, meal planning, and other behavior changes among service members. Importantly, the military is attempting to tackle environmental factors contributing to the rise of obesity, by focusing on many recent environmental-level interventions and initiatives to improve military dining facilities and examine and modify other aspects of installations' built environments. Although published research within the military setting directed towards obesity prevention is limited, many innovative programs have been launched and need to be followed forward. The review of past and ongoing efforts can be an important step in identifying specific areas needing improvement, gaps that should be considered, lessons learned, and characteristics of successful programs that should be disseminated as best practices and further expanded.

Need for "conflict version" of primary surgery: war surgery in the era of low-intensity conflicts.

PubMed

Morikawa, Masahiro J

2006-01-01

The conventional wars between nations have widely been replaced by low-intensity conflicts within nations today, resulting in different patterns of injuries and practice of surgical care. A blurred front line, protracted durations of violence, indiscriminant fighting, and the emergence of specific surgical problems characterize low-intensity conflicts. In protracted conflicts with limited resources, surgical outcomes depend on many factors other than surgical skills, such as social/cultural values and economical feasibility. This paper examines how the characteristics of current conflicts affect surgical practice and will address key issues to evolve care to adapt to these changes. Key issues are (1) need for comprehensive surgical skills, (2) importance of improving local capacities, (3) long-term impact of trauma, and (4) limited access to information required to improve surgical skills.

Improving stability and strength characteristics of framed structures with nonlinear behavior

NASA Technical Reports Server (NTRS)

Pezeshk, Shahram

1990-01-01

In this paper an optimal design procedure is introduced to improve the overall performance of nonlinear framed structures. The design methodology presented here is a multiple-objective optimization procedure whose objective functions involve the buckling eigenvalues and eigenvectors of the structure. A constant volume with bounds on the design variables is used in conjunction with an optimality criterion approach. The method provides a general tool for solving complex design problems and generally leads to structures with better limit strength and stability. Many algorithms have been developed to improve the limit strength of structures. In most applications geometrically linear analysis is employed with the consequence that overall strength of the design is overestimated. Directly optimizing the limit load of the structure would require a full nonlinear analysis at each iteration which would be prohibitively expensive. The objective of this paper is to develop an algorithm that can improve the limit-load of geometrically nonlinear framed structures while avoiding the nonlinear analysis. One of the novelties of the new design methodology is its ability to efficiently model and design structures under multiple loading conditions. These loading conditions can be different factored loads or any kind of loads that can be applied to the structure simultaneously or independently. Attention is focused on optimal design of space framed structures. Three-dimensional design problems are more complicated to carry out, but they yield insight into real behavior of the structure and can help avoiding some of the problems that might appear in planar design procedure such as the need for out-of-plane buckling constraint. Although researchers in the field of structural engineering generally agree that optimum design of three-dimension building frames especially in the seismic regions would be beneficial, methods have been slow to emerge. Most of the research in this area has dealt with the optimization of truss and plane frame structures.

Self Regulation, Cognitive Capacity and Risk Taking: Investigating Heterogeneity Among Adolescents with Callous-Unemotional Traits.

PubMed

Hadjicharalambous, Maria-Zoe; Fanti, Kostas A

2018-06-01

The majority of prior work focuses on understanding the association between callous-unemotional (CU) traits and conduct problems, providing limited information on why some youth who score high on CU traits do not engage in conduct problem behaviors. The current study investigated heterogeneity among a sub-sample of adolescents with CU traits (N = 152; Mage = 13.09, SD = 2.76, 45.6% female) identified from a large community sample. Three groups were compared: control, callous-unemotional traits only (CU-only), and combined callous-unemotional and conduct problems (CU + CP). Participants were administered a battery of neuropsychological computerized tasks assessing risk taking, self-regulation and cognitive capacity. Results indicated that youth high on CU traits and low on CP scored higher on self-regulation and were less likely to make risky decisions compared to youth with combined CU + CP. In general, the findings provided information that heterogeneity within CU traits can be explained based on differences in neuro-cognitive functioning. In addition, the characteristics of youth high on CU traits only can provide information for interventions aiming to decrease conduct problems among youth high on these traits.

Applying Flammability Limit Probabilities and the Normoxic Upward Limiting Pressure Concept to NASA STD-6001 Test 1

NASA Technical Reports Server (NTRS)

Olson, Sandra L.; Beeson, Harold; Fernandez-Pello, A. Carlos

2014-01-01

Repeated Test 1 extinction tests near the upward flammability limit are expected to follow a Poisson process trend. This Poisson process trend suggests that rather than define a ULOI and MOC (which requires two limits to be determined), it might be better to define a single upward limit as being where 1/e (where e (approx. equal to 2.7183) is the characteristic time of the normalized Poisson process) of the materials burn, or, rounding, where approximately 1/3 of the samples fail the test (and burn). Recognizing that spacecraft atmospheres will not bound the entire oxygen-pressure parameter space, but actually lie along the normoxic atmosphere control band, we can focus the materials flammability testing along this normoxic band. A Normoxic Upward Limiting Pressure (NULP) is defined that determines the minimum safe total pressure for a material within the constant partial pressure control band. Then, increasing this pressure limit by a factor of safety, we can define the material as being safe to use at the NULP + SF (where SF is on the order of 10 kilopascal, based on existing flammability data). It is recommended that the thickest material to be tested with the current Test 1 igniter should be 3 mm thick (1/8 inches) to avoid the problem of differentiating between an ignition limit and a true flammability limit.

Electromagnetic Wave Excitation by a Longitudinal Slot in a Broad Wall of Rectangular Waveguide in the Presence of Passive Impedance Vibrators Outside the Waveguide

NASA Astrophysics Data System (ADS)

Berdnik, S. L.; Katrich, V. A.; Nesterenko, M. V.; Penkin, Yu. M.

2016-09-01

Purpose: A problem of electromagnetic wave diffraction by a longitudinal slot cut in a waveguide wide wall is solved. The slot is cut in a wide wall of a rectangular waveguide and radiates in a half-space above a perfectly conducting plane where two vertical impedance monopoles with arbitrary lengths placed with their bases placed on the plane. The paper is aimed at studying the electrodynamic characteristics of vibratorwaveguide-slot structures which allow to form the emission fields as that in a Clavin element with two identical passive ideally conducting monopoles of a fixed length located on a set distance from a slot center on both sides of a narrow halfwave slot. Design/methodology/approach: The problem is solved by a generalized method of induced electromotive and magnetomotive forces in approximation of electric currents in the vibrators and equivalent magnetic current in the slot by the functions obtained by the asymptotic averaging method. Findings: The influence of geometric parameters of the structure on the directional characteristics of Clavin type element is analyzed on the assumption of simultaneous account for relative level of sidelobes in the E-plane and beamwidth differences at -3 dB level in the main planes. It is shown that the directional characteristics and energy characteristics of the radiators: radiation and reflection coefficients, antenna directivity and gain can be varied within wide limits by changing the electrical length and/or distributed surface impedances of the vibrators, providing at that a low level of radiation within a slot plane. Conclusions: The results obtained can be useful when designing both small-size and multi-element antenna arrays with Clavin elements.

Current status and prospect: Coal water mixture technology in Indonesia

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

Sastrawinata, T.; Suwono, A.

1996-12-31

This paper covers the status of Coal Water Mixture (CWM) technology in Indonesia and also the prospect for implementing this technology. Advantageous use of a pipeline for coal transportation is geographically inconvenient. Characteristics of CWM for Indonesian coal and combustion characteristics of CWM for Indonesian coal are reviewed. The coal reserve estimated in Indonesia is about 36 billions tons with ratio of lignite and higher rank is 60:40. The main problems faced in the coal utilization in Indonesia is the transportation from the mines to the users. Remote, limited infrastructure and the geographic conditions are factors which contribute to themore » problems. The CWM made of Indonesian low rank coal from various origins has been prepared for further study. The CWM of various coal concentration up to 66% with good handling and storage stability was obtained. Rheological measurements of the obtained CWM shows that for high coal concentration (greater than about 40%), in addition to the yield stress, the solution also behaves as the power law model of fluid. Energy Technology Laboratory has just started to investigate the combustion characteristics of CWM. CWM in Indonesia has not been utilized commercially in the industrial boiler, so that needs to be studied comprehensively. The technical aspects in this is stressed on the combustion characteristics in the boiler furnace. LSDE has a state of the art coal combustion facility that includes a chemical analytic laboratory and a boiler simulator equipped with complete data acquisition. The experiments will have several numerical criteria to characterize CWS combustion process, i.e., Maximum Furnace Exit Temperature, firing rate, pressure drop in the test section, deposit strength and deposit weight, swirl flow number.« less

Family factors and life events as risk factors for behavioural and emotional problems in children.

PubMed

Harland, P; Reijneveld, S A; Brugman, E; Verloove-Vanhorick, S P; Verhulst, F C

2002-08-01

The aim of this study was to identify groups of children at increased risk of behavioural or emotional problems on the basis of socio-demographic characteristics, family characteristics, and recent life events with a focus on unemployment and divorce or separation. We obtained data on the Child Behavior Checklist (CBCL) from a community-based national sample of 4480 parents of school-aged children and interviewed them about their demographic and family characteristics and about the child's recent life events. Results showed that family characteristics and recent life events were more strongly associated with children's risks of behavioural and emotional problems as measured by the CBCL than other demographic characteristics. Risks were somewhat higher for children who had experienced parental unemployment and divorce or separation recently, as compared to those who had experienced these events in the more distant past. We conclude that children with recent experience of parental unemployment or parental divorce or separation are at a relatively high risk of behavioural and emotional problems as reported by parents. Although relatively high, the risks that were found do not justify restriction of screening for behavioural and emotional problems to these children.

Perception and Selection of Information Sources by Undergraduate Students: Effects of Avoidant Style, Confidence, and Personal Control in Problem-Solving

ERIC Educational Resources Information Center

Kim, Kyung-Sun; Sin, Sei-Ching Joanna

2007-01-01

A survey of undergraduate students examined how students' beliefs about their problem-solving styles and abilities (including avoidant style, confidence, and personal control in problem-solving) influenced their perception and selection of sources, as reflected in (1) perceived characteristics of sources, (2) source characteristics considered…

The name-locator guide: A new resource for technology transfer

NASA Technical Reports Server (NTRS)

Clingman, W. H.

1974-01-01

A new transfer mechanism to facilitate technology transfer between aerospace technology and nonaerospace industries, was proposed with the following sequence of steps. First, the key technical problems in a given industry would be analyzed. The analysis will define the characteristics which relevant technology will have. Second, a limited list of subject terms will be developed using words familiar to those working in the industry. It is these which will be applied in subsequent steps to the NASA technology and used to locate technology relevant to a specific problem in the industry. Third, for each Required Technology Program, terms applicable to that program would be chosen from this list. Fourth, a name-locator guide would be provided to the Regional Dissemination Centers. This guide would be analogous to an index. The key words would be chosen from the special subject term list for the given industry.

Satellite-borne active phased array techniques for mobile communications

NASA Astrophysics Data System (ADS)

Sheehan, P. G.; Forrest, J. R.

1986-07-01

This paper investigates the design of active phased arrays for communications satellites. In particular, consideration is given to the problems occurring when active arrays are required to produce multiple beams. There is a real need to keep the complexity of the array electronics to a minimum, but this conflicts with the desire to obtain the greatest possible freedom of control of the radiation pattern produced. The paper demonstrates a method of coping with the problem. Low-gain elements are used to provide design freedom and they are grouped into subarrays to limit the complexity of the rest of the system. With appropriate configurations of subarrays, greatly improved radiation pattern characteristics can be obtained and frequency reuse between multiple beams becomes feasible. A demonstration model of 108 microstrip patches grouped into 32 subarrays, operating at 12 GHz, has been constructed and verifies that the technique is effective.

Verbal marital conflict and male domination in the family as risk factors of intimate partner violence.

PubMed

Vives-Cases, Carmen; Gil-González, Diana; Carrasco-Portiño, Mercedes

2009-04-01

A systematic review was performed to analyse the characteristics and quality of the studies that consider the relationship between verbal marital conflict and/or male domination in the family and violent behaviour by men towards their partner. Only 11 articles were identified between 1986 and 2006. Most of them find a positive association between male domination in the family and/or verbal marital conflict and violence towards the woman in the couple. However, limitations such as misclassification bias, recall bias, selection bias, external validity and the problem of consistency (overestimation of effect) were acknowledged by authors of this studies. In eight of the 11 studies reviewed, preventive measures or interventions to deal with the problem were recommended. More and better empirical evidence is required in order to provide suitable measures to address the issue of verbal marital conflict and male domination and its influence on IPV.

An overview of silicon carbide device technology

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.; Matus, Lawrence G.

1992-01-01

Recent progress in the development of silicon carbide (SiC) as a semiconductor is briefly reviewed. This material shows great promise towards providing electronic devices that can operate under the high-temperature, high-radiation, and/or high-power conditions where current semiconductor technologies fail. High quality single crystal wafers have become available, and techniques for growing high quality epilayers have been refined to the point where experimental SiC devices and circuits can be developed. The prototype diodes and transistors that have been produced to date show encouraging characteristics, but by the same token they also exhibit some device-related problems that are not unlike those faced in the early days of silicon technology development. Although these problems will not prevent the implementation of some useful circuits, the performance and operating regime of SiC electronics will be limited until these device-related issues are solved.

Optimization of LED light spectrum to enhance colorfulness of illuminated objects with white light constraints.

PubMed

Wu, Haining; Dong, Jianfei; Qi, Gaojin; Zhang, Guoqi

2015-07-01

Enhancing the colorfulness of illuminated objects is a promising application of LED lighting for commercial, exhibiting, and scientific purposes. This paper proposes a method to enhance the color of illuminated objects for a given polychromatic lamp. Meanwhile, the light color is restricted to white. We further relax the white light constraints by introducing soft margins. Based on the spectral and electrical characteristics of LEDs and object surface properties, we determine the optimal mixing of the LED light spectrum by solving a numerical optimization problem, which is a quadratic fractional programming problem by formulation. Simulation studies show that the trade-off between the white light constraint and the level of the color enhancement can be adjusted by tuning an upper limit value of the soft margin. Furthermore, visual evaluation experiments are performed to evaluate human perception of the color enhancement. The experiments have verified the effectiveness of the proposed method.

Characteristics of Students' Mathematical Promise When Engaging with Problem-Based Learning Units in Primary Classrooms

ERIC Educational Resources Information Center

Trinter, Christine P.; Moon, Tonya R.; Brighton, Catherine M.

2015-01-01

The purpose of this qualitative study was to provide empirical evidence of the extent to which the types of tasks recommended by Sheffield for eliciting characteristics of mathematical promise allowed for the manifestation of these characteristics in primary-grade students within a problem-based learning (PBL) context. Data included student work…

The Structure of Pathological Gambling among Korean Gamblers: A Cluster and Factor Analysis of Clinical and Demographic Characteristics

ERIC Educational Resources Information Center

Lee, Tae Kyung; LaBrie, Richard A.; Grant, Jon E.; Kim, Suck Won; Shaffer, Howard J.

2008-01-01

This paper reports the underlying structure of the demographic and clinical characteristics of level 3 (i.e., pathological) Korean casino gamblers. The participants reported their gambling behavior and clinical characteristics known to be associated with gambling problems (e.g., alcohol use problems, eating disorders, depression, anxiety, and…

A sparse reconstruction method for the estimation of multiresolution emission fields via atmospheric inversion

DOE PAGES

Ray, J.; Lee, J.; Yadav, V.; ...

2014-08-20

We present a sparse reconstruction scheme that can also be used to ensure non-negativity when fitting wavelet-based random field models to limited observations in non-rectangular geometries. The method is relevant when multiresolution fields are estimated using linear inverse problems. Examples include the estimation of emission fields for many anthropogenic pollutants using atmospheric inversion or hydraulic conductivity in aquifers from flow measurements. The scheme is based on three new developments. Firstly, we extend an existing sparse reconstruction method, Stagewise Orthogonal Matching Pursuit (StOMP), to incorporate prior information on the target field. Secondly, we develop an iterative method that uses StOMP tomore » impose non-negativity on the estimated field. Finally, we devise a method, based on compressive sensing, to limit the estimated field within an irregularly shaped domain. We demonstrate the method on the estimation of fossil-fuel CO 2 (ffCO 2) emissions in the lower 48 states of the US. The application uses a recently developed multiresolution random field model and synthetic observations of ffCO 2 concentrations from a limited set of measurement sites. We find that our method for limiting the estimated field within an irregularly shaped region is about a factor of 10 faster than conventional approaches. It also reduces the overall computational cost by a factor of two. Further, the sparse reconstruction scheme imposes non-negativity without introducing strong nonlinearities, such as those introduced by employing log-transformed fields, and thus reaps the benefits of simplicity and computational speed that are characteristic of linear inverse problems.« less

Psychological Characteristics in Acute Mild Traumatic Brain Injury: An MMPI-2 Study.

PubMed

Gass, Carlton S; Rogers, David; Kinne, Erica

2017-01-01

The psychological characteristics of acute traumatic brain injury (TBI) have received limited research focus, despite empirical evidence of their relevance for subsequent psychological adjustment and early therapeutic intervention. This study addressed a wide range of psychological features in 47 individuals who were hospitalized as a result of acute mild TBI (mTBI). Participants were screened from amongst consecutive TBI admissions for moderate to severe brain injury, and for pre-injury neurological, psychiatric, or substance abuse histories. Clinical and content scale scores on the MMPI-2 were explored in relation to patient gender, age, level of education, and extent of cognitive complaints. The results revealed diverse psychosocial problem areas across the sample, the most common of which were somatic and cognitive complaints, compromised insight, and a naively optimistic self-perception. The mediating roles of injury severity and demographic variables are discussed. Clinical implications and specific recommendations are presented.

Linear conduction in N-type organic field effect transistors with nanometric channel lengths and graphene as electrodes

NASA Astrophysics Data System (ADS)

Chianese, F.; Candini, A.; Affronte, M.; Mishra, N.; Coletti, C.; Cassinese, A.

2018-05-01

In this work, we test graphene electrodes in nanometric channel n-type Organic Field Effect Transistors (OFETs) based on thermally evaporated thin films of the perylene-3,4,9,10-tetracarboxylic acid diimide derivative. By a thorough comparison with short channel transistors made with reference gold electrodes, we found that the output characteristics of the graphene-based devices respond linearly to the applied bias, in contrast with the supralinear trend of gold-based transistors. Moreover, short channel effects are considerably suppressed in graphene electrode devices. More specifically, current on/off ratios independent of the channel length (L) and enhanced response for high longitudinal biases are demonstrated for L down to ˜140 nm. These results are rationalized taking into account the morphological and electronic characteristics of graphene, showing that the use of graphene electrodes may help to overcome the problem of Space Charge Limited Current in short channel OFETs.

Preschoolers' psychosocial problems: in the eyes of the beholder? Adding teacher characteristics as determinants of discrepant parent-teacher reports.

PubMed

Berg-Nielsen, Turid Suzanne; Solheim, Elisabet; Belsky, Jay; Wichstrom, Lars

2012-06-01

In this study, we explored informant characteristics as determinants of parent-teacher disagreement on preschoolers' psychosocial problems. Teacher characteristics were included in the analyses, in addition to child and parent factors. Psychosocial problems of 732 4-year olds from a Norwegian community sample were assessed by parents and teachers (CBCL-TRF). Furthermore, teachers reported on their education, experience and relationship to the child. Parental stress and psychopathology were also measured. Teachers rated children considerably lower than their parents did, especially on internalizing problems. When teachers rated more child problems, this was strongly associated with conflict in the teacher-child relationship, which predicted disagreement more than other factors. The highest agreement was on boys' externalizing problems. Girls' behavior was rated much lower by teachers than boys' behavior compared to parents' ratings. Possible teacher perception biases are discussed, such as teacher-child conflict, non-identification of internalizing problems, and same-gender child preference.

Biopsychosocial Characteristics of Community-dwelling Older Adults with Limited Ability to Walk ¼ Mile

PubMed Central

Hardy, Susan E.; McGurl, David J.; Studenski, Stephanie A.; Degenholtz, Howard B.

2010-01-01

Objectives To establish nationally representative estimates of the prevalence of self-reported difficulty and inability to walk ¼ mile among older adults and to identify the characteristics independently associated with difficulty or inability to walk ¼ mile. Design Cross-sectional analysis of data from the 2003 Cost and Use Medicare Current Beneficiary Survey. Setting Community. Participants 9563 community-dwelling Medicare beneficiaries aged 65 years or older, representing an estimated total population of 34.2 million older adults. Measurements Self-reported ability to walk ¼ mile, sociodemographics, chronic conditions, body mass index, smoking, and functional status. Results In 2003, an estimated 9.5 million aged Medicare beneficiaries had difficulty walking ¼ mile and 5.9 million were unable. Among the 20.2 million older adults with no difficulty in basic or instrumental activities of daily living (ADL), an estimated 4.3 million (21%) had limited ability to walk ¼ mile. Having difficulty or being unable to walk ¼ mile was independently associated with older age, female sex, non-Hispanic ethnicity, lower educational level, Medicaid entitlement, most chronic medical conditions, current smoking, and being overweight or obese. Conclusion Almost half of older adults, and 20% of those reporting no ADL limitations, report limited ability to walk ¼ mile. Among functionally independent older adults, reported ability to walk ¼ mile can identify vulnerable older adults with greater medical problems and fewer resources, and may be a valuable clinical marker in planning their care. Future work is needed to determine the association between ¼ mile walk ability and subsequent functional decline and healthcare utilization. PMID:20210817

Flight Studies of Problems Pertinent to High-Speed Operation of Jet Transports

NASA Technical Reports Server (NTRS)

Butchart, Stanley P.; Fischel, Jack; Tremant, Robert A.; Robinson, Glenn H.

1959-01-01

A flight investigation was made to assess the potential operational problems of jet transports in the transonic cruise range. In this study a large multiengine jet airplane having geometric characteristics fairly representative of the jet transport was used; however, in order to ensure general applicability of the results, the aerodynamic characteristics of the test airplane were varied to simulate a variety of jet- transport airplanes. Some of the specific areas investigated include: (1) an overall evaluation of longitudinal stability and control characteristics at transonic speeds, with an assessment of pitch-up characteristics, (2) the effect of buffeting on airplane operational speeds and maneuvering, (3) the desirable lateral-directional damping characteristics, (4) the desirable lateral-control characteristics, (5) an assessment of over-speed and speed-spread requirements, including the upset maneuver, and (6) an assessment of techniques and airplane characteristics for rapid descent and slow-down. The results presented include pilots' evaluation of the various problem areas and specific recommendations for possible improvement of jet-transport operations in the cruising speed range.

Chromatographic test methods for characterizing alkylsiloxane-bonded silica columns for reversed-phase liquid chromatography.

PubMed

Poole, Colin F

2018-06-07

Major obstacles to formulating a simple retention mechanism for reversed-phase liquid chromatography have a direct impact on the development of experimental methods for column characterization as they limit our capability to understand observed differences in retention at a system level. These problems arise from the heterogeneous composition of the stationary phase, the difficulty of providing a working definition for the phase ratio, and uncertainty as to whether the distribution mechanism for varied compounds is a partition, adsorption or mixed (combination) of these models. Retention factor and separation factor measurements offer little guidance as they represent an average of various and variable contributing factors that can only be interpreted by assuming a specific model. Column characterization methods have tended to ignore these difficulties by inventing a series of terms to describe column properties, such as hydrophobicity, hydrophilicity, silanol activity, steric resistance, etc., without proper definition. This has allowed multiple scales to be proposed for the same property which generally are only weakly correlated. Against this background we review the major approaches for the characterization of alkylsiloxane-bonded silica stationary phases employing prototypical compounds, the hydrophobic-subtraction model and the solvation parameter model. Those methods using prototypical compounds are limited by the lack of compounds with a singular dominant interaction. The multivariate approaches that extract column characteristic properties from the retention of varied compounds are more hopeful but it is important to be more precise in defining the characteristic column properties and cognizant that general interpretation of these properties for varied columns cannot escape the problem of a poor understanding of the distribution mechanism. Copyright © 2018 Elsevier B.V. All rights reserved.

Healthcare provider attitudes towards the problem list in an electronic health record: a mixed-methods qualitative study

PubMed Central

2012-01-01

Background The problem list is a key part of the electronic health record (EHR) that allows practitioners to see a patient’s diagnoses and health issues. Yet, as the content of the problem list largely represents the subjective decisions of those who edit it, patients’ problem lists are often unreliable when shared across practitioners. The lack of standards for how the problem list is compiled in the EHR limits its effectiveness in improving patient care, particularly as a resource for clinical decision support and population management tools. The purpose of this study is to discover practitioner opinions towards the problem list and the logic behind their decisions during clinical situations. Materials and methods An observational cross-sectional study was conducted at two major Boston teaching hospitals. Practitioners’ opinions about the problem list were collected through both in-person interviews and an online questionnaire. Questions were framed using vignettes of clinical scenarios asking practitioners about their preferred actions towards the problem list. Results These data confirmed prior research that practitioners differ in their opinions over managing the problem list, but in most responses to a questionnaire, there was a common approach among the relative majority of respondents. Further, basic demographic characteristics of providers (age, medical experience, etc.) did not appear to strongly affect attitudes towards the problem list. Conclusion The results supported the premise that policies and EHR tools are needed to bring about a common approach. Further, the findings helped identify what issues might benefit the most from a defined policy and the level of restriction a problem list policy should place on the addition of different types of information. PMID:23140312

Impact of future fuel properties on aircraft engines and fuel systems

NASA Technical Reports Server (NTRS)

Rudey, R. A.; Grobman, J. S.

1978-01-01

From current projections of the availability of high-quality petroleum crude oils, it is becoming increasingly apparent that the specifications for hydrocarbon jet fuels may have to be modified. The problems that are most likely to be encountered as a result of these modifications relate to engine performance, component durability and maintenance, and aircraft fuel-system performance. The effect on engine performance will be associated with changes in specific fuel consumption, ignition at relight limits, at exhaust emissions. Durability and maintenance will be affected by increases in combustor liner temperatures, carbon deposition, gum formation in fuel nozzles, and erosion and corrosion of turbine blades and vanes. Aircraft fuel-system performance will be affected by increased deposits in fuel-system heat exchangers and changes in the pumpability and flowability of the fuel. The severity of the potential problems is described in terms of the fuel characteristics most likely to change in the future. Recent data that evaluate the ability of current-technology aircraft to accept fuel specification changes are presented, and selected technological advances that can reduce the severity of the problems are described and discussed.

An Explicit Linear Filtering Solution for the Optimization of Guidance Systems with Statistical Inputs

NASA Technical Reports Server (NTRS)

Stewart, Elwood C.

1961-01-01

The determination of optimum filtering characteristics for guidance system design is generally a tedious process which cannot usually be carried out in general terms. In this report a simple explicit solution is given which is applicable to many different types of problems. It is shown to be applicable to problems which involve optimization of constant-coefficient guidance systems and time-varying homing type systems for several stationary and nonstationary inputs. The solution is also applicable to off-design performance, that is, the evaluation of system performance for inputs for which the system was not specifically optimized. The solution is given in generalized form in terms of the minimum theoretical error, the optimum transfer functions, and the optimum transient response. The effects of input signal, contaminating noise, and limitations on the response are included. From the results given, it is possible in an interception problem, for example, to rapidly assess the effects on minimum theoretical error of such factors as target noise and missile acceleration. It is also possible to answer important questions regarding the effect of type of target maneuver on optimum performance.

Can Childhood Factors Predict Workplace Deviance?

PubMed Central

Piquero, Nicole Leeper; Moffitt, Terrie E.

2013-01-01

Compared to the more common focus on street crime, empirical research on workplace deviance has been hampered by highly select samples, cross-sectional research designs, and limited inclusion of relevant predictor variables that bear on important theoretical debates. A key debate concerns the extent to which childhood conduct-problem trajectories influence crime over the life-course, including adults’ workplace crime, whether childhood low self-control is a more important determinant than trajectories, and/or whether each or both of these childhood factors relate to later criminal activity. This paper provides evidence on this debate by examining two types of workplace deviance: production and property deviance separately for males and females. We use data from the Dunedin Multidisciplinary Health and Development Study, a birth cohort followed into adulthood, to examine how childhood factors (conduct-problem trajectories and low self-control) and then adult job characteristics predict workplace deviance at age 32. Analyses revealed that none of the childhood factors matter for predicting female deviance in the workplace but that conduct-problem trajectories did account for male workplace deviance. PMID:24882937

Intercomparison of magnetic field measurements near MV/LV transformer substations: methodological planning and results.

PubMed

Violanti, S; Fraschetta, M; Adda, S; Caputo, E

2009-12-01

Within the framework of Environmental Agencies system's activities, coordinated by ISPRA (superior institute for environmental protection and research), a comparison among measurements was designed and accomplished, in order to go into depth on the matter of measurement problems and to evaluate magnetic field at power frequencies. These measurements have been taken near medium voltage /low voltage transformer substation. This project was developed with the contribution of several experts who belong to different Regional Agencies. In three of these regions, substations having specific international standard characteristics were chosen; then a measurement and data analysis protocol was arranged. Data analysis showed a good level of coherence among results obtained by different laboratories. However, a range of problems emerged, either during the protocol predisposition and definition of the data analysis procedure or during the execution of measures and data reprocessing, because of the spatial and temporal variability of magnetic field. These problems represent elements of particular interest in determining a correct measurement methodology, whose purpose is the comparison with limits of exposure, attention values and quality targets.

A Flight Examination of Operating Problems of V/STOL Aircraft in STOL-Type Landing and Approach

NASA Technical Reports Server (NTRS)

Innis, Robert C.; Quigley, Hervey C.

1961-01-01

A flight investigation has been conducted using a large twin-engine cargo aircraft to isolate the problems associated with operating propeller-driven aircraft in the STOL speed range where appreciable engine power is used to augment aerodynamic lift. The problems considered would also be representative of those of a large overloaded VTOL aircraft operating in an STOL manner with comparable thrust-to-weight ratios. The study showed that operation at low approach speeds was compromised by the necessity of maintaining high thrust to generate high lift and yet achieving the low lift-drag ratios needed for steep descents. The useable range of airspeed and flight path angle was limited by the pilot's demand for a positive climb margin at the approach speed, a suitable stall margin, and a control and/or performance margin for one engine inoperative. The optimum approach angle over an obstacle was found to be a compromise between obtaining the shortest air distance and the lowest touchdown velocity. In order to realize the greatest low-speed potential from STOL designs, the stability and control characteristics must be satisfactory.

Pan-sharpening via compressed superresolution reconstruction and multidictionary learning

NASA Astrophysics Data System (ADS)

Shi, Cheng; Liu, Fang; Li, Lingling; Jiao, Licheng; Hao, Hongxia; Shang, Ronghua; Li, Yangyang

2018-01-01

In recent compressed sensing (CS)-based pan-sharpening algorithms, pan-sharpening performance is affected by two key problems. One is that there are always errors between the high-resolution panchromatic (HRP) image and the linear weighted high-resolution multispectral (HRM) image, resulting in spatial and spectral information lost. The other is that the dictionary construction process depends on the nontruth training samples. These problems have limited applications to CS-based pan-sharpening algorithm. To solve these two problems, we propose a pan-sharpening algorithm via compressed superresolution reconstruction and multidictionary learning. Through a two-stage implementation, compressed superresolution reconstruction model reduces the error effectively between the HRP and the linear weighted HRM images. Meanwhile, the multidictionary with ridgelet and curvelet is learned for both the two stages in the superresolution reconstruction process. Since ridgelet and curvelet can better capture the structure and directional characteristics, a better reconstruction result can be obtained. Experiments are done on the QuickBird and IKONOS satellites images. The results indicate that the proposed algorithm is competitive compared with the recent CS-based pan-sharpening methods and other well-known methods.

Youth Characteristics Associated with Behavioral and Mental Health Problems during the Transition to Residential Treatment Centers: The Odyssey Project Population

ERIC Educational Resources Information Center

Baker, Amy J. L.; Archer, Marc; Curtis, Patrick

2007-01-01

This study aimed to determine what youth characteristics were associated with emotional and behavioral problems exhibited within the first three months of placement in residential treatment centers (RTCs) in a sample of youth from 20 agencies in 13 states. Two primary research questions were addressed: 1) What characteristics were associated with…

Testosterone Administration Moderates Effect of Social Environment on Trust in Women Depending on Second-to-Fourth Digit Ratio

PubMed Central

Buskens, Vincent; Raub, Werner; van Miltenburg, Nynke; Montoya, Estrella R.; van Honk, Jack

2016-01-01

Animal research has established that effects of hormones on social behaviour depend on characteristics of both individual and environment. Insight from research on humans into this interdependence is limited, though. Specifically, hardly any prior testosterone experiments in humans scrutinized the interdependency of testosterone with the social environment. Nonetheless, recent testosterone administration studies in humans repeatedly show that a proxy for individuals’ prenatal testosterone-to-estradiol ratio, second-to-fourth digit-ratio (2D:4D ratio), influences effects of testosterone administration on human social behaviour. Here, we systematically vary the characteristics of the social environment and show that, depending on prenatal sex hormone priming, testosterone administration in women moderates the effect of the social environment on trust. We use the economic trust game and compare one-shot games modelling trust problems in relations between strangers with repeated games modelling trust problems in ongoing relations between partners. As expected, subjects are more trustful in repeated than in one-shot games. In subjects prenatally relatively highly primed by testosterone, however, this effect disappears after testosterone administration. We argue that impairments in cognitive empathy may reduce the repeated game effect on trust after testosterone administration in subjects with relatively high prenatal testosterone exposure and propose a neurobiological explanation for this effect. PMID:27282952

Testosterone Administration Moderates Effect of Social Environment on Trust in Women Depending on Second-to-Fourth Digit Ratio.

PubMed

Buskens, Vincent; Raub, Werner; van Miltenburg, Nynke; Montoya, Estrella R; van Honk, Jack

2016-06-10

Animal research has established that effects of hormones on social behaviour depend on characteristics of both individual and environment. Insight from research on humans into this interdependence is limited, though. Specifically, hardly any prior testosterone experiments in humans scrutinized the interdependency of testosterone with the social environment. Nonetheless, recent testosterone administration studies in humans repeatedly show that a proxy for individuals' prenatal testosterone-to-estradiol ratio, second-to-fourth digit-ratio (2D:4D ratio), influences effects of testosterone administration on human social behaviour. Here, we systematically vary the characteristics of the social environment and show that, depending on prenatal sex hormone priming, testosterone administration in women moderates the effect of the social environment on trust. We use the economic trust game and compare one-shot games modelling trust problems in relations between strangers with repeated games modelling trust problems in ongoing relations between partners. As expected, subjects are more trustful in repeated than in one-shot games. In subjects prenatally relatively highly primed by testosterone, however, this effect disappears after testosterone administration. We argue that impairments in cognitive empathy may reduce the repeated game effect on trust after testosterone administration in subjects with relatively high prenatal testosterone exposure and propose a neurobiological explanation for this effect.

Thermophysical fundamentals of cyclonic recirculating heating devices

NASA Astrophysics Data System (ADS)

Karpov, S. V.; Zagoskin, A. A.

2017-10-01

This report presents the results of experimental and theoretical research of aerodynamics and convective heat transfer in cyclone devices with the new system of external recirculation of heating gas under the influence of radial pressure gradient in a heat carrier’s swirling turbulent flow. The dynamic problem of tangential velocity distribution in a clearance volume is solved at various re-circulation ratio values including limiting quantities (kr = 0; 1) and variations in cyclonic combustion chamber’s design parameters and operating conditions (Rer); the integrated calculation ratios for fundamental aerodynamic characteristics of a recirculation device are derived. The first experimental and numerical studies of convective heat transfer on internal and external surfaces of a hollow shaft in a swirling recirculation flow are derived through the instrumentality of OpenFOAM, these studies are also conducted for a setting of several cylindrical solid inserts. The external surface heat problem of a hollow cylindrical insert is solved with integral and digital methods; generalized similarity equations for the internal and external surfaces extended in range of Reynolds number are derived. The experimental data is in reasonable agreement with the derived curves and the results of mathematic modelling of convective heat transfer. Calculation recommendations for optimal selection of kr values at various ratios of their geometric characteristics and products utilization rate are obtained.

[Precarious employment in undocumented immigrants in Spain and its relationship with health].

PubMed

Porthé, Victoria; Benavides, Fernando G; Vázquez, M Luisa; Ruiz-Frutos, Carlos; García, Ana M; Ahonen, Emily; Agudelo-Suárez, Andrés A; Benach, Joan

2009-12-01

To describe the characteristics of precarious employment in undocumented immigrants in Spain and its relationship with health. A qualitative study was conducted using analytic induction. Criterion sampling, based on the Immigration, Work and Health project (Inmigración, Trabajo y Salud [ITSAL]) criterion (current definitions of 'legal immigrant' in Spain and in the literature) was used to recruit 44 undocumented immigrant workers from four different countries, living in four Spanish cities. The characteristics of precariousness perceived by undocumented immigrants included high job instability; disempowerment due to lack of legal protection; high vulnerability exacerbated by their legal and immigrant status; perceived insufficient wages and lower wages than coworkers; limited social benefits and difficulty in exercising their rights; and finally, long hours and fast-paced work. Our informants reported they had no serious health problems but did describe physical and mental problems associated with their employment conditions and legal situation. Our results suggest that undocumented immigrants' situation may not fit the model of precarious employment exactly. However, the model's dimensions can be expanded to better represent undocumented immigrants' situation, thus strengthening the general model. Precarious employment in this group can be defined as , as it affects their working and social lives. If these workers continue to be exposed to such precarious conditions, the impact on their health may increase.

Helicopter flights with night-vision goggles: Human factors aspects

NASA Technical Reports Server (NTRS)

Brickner, Michael S.

1989-01-01

Night-vision goggles (NVGs) and, in particular, the advanced, helmet-mounted Aviators Night-Vision-Imaging System (ANVIS) allows helicopter pilots to perform low-level flight at night. It consists of light intensifier tubes which amplify low-intensity ambient illumination (star and moon light) and an optical system which together produce a bright image of the scene. However, these NVGs do not turn night into day, and, while they may often provide significant advantages over unaided night flight, they may also result in visual fatigue, high workload, and safety hazards. These problems reflect both system limitations and human-factors issues. A brief description of the technical characteristics of NVGs and of human night-vision capabilities is followed by a description and analysis of specific perceptual problems which occur with the use of NVGs in flight. Some of the issues addressed include: limitations imposed by a restricted field of view; problems related to binocular rivalry; the consequences of inappropriate focusing of the eye; the effects of ambient illumination levels and of various types of terrain on image quality; difficulties in distance and slope estimation; effects of dazzling; and visual fatigue and superimposed symbology. These issues are described and analyzed in terms of their possible consequences on helicopter pilot performance. The additional influence of individual differences among pilots is emphasized. Thermal imaging systems (forward looking infrared (FLIR)) are described briefly and compared to light intensifier systems (NVGs). Many of the phenomena which are described are not readily understood. More research is required to better understand the human-factors problems created by the use of NVGs and other night-vision aids, to enhance system design, and to improve training methods and simulation techniques.

Inverse problems and optimal experiment design in unsteady heat transfer processes identification

NASA Technical Reports Server (NTRS)

Artyukhin, Eugene A.

1991-01-01

Experimental-computational methods for estimating characteristics of unsteady heat transfer processes are analyzed. The methods are based on the principles of distributed parameter system identification. The theoretical basis of such methods is the numerical solution of nonlinear ill-posed inverse heat transfer problems and optimal experiment design problems. Numerical techniques for solving problems are briefly reviewed. The results of the practical application of identification methods are demonstrated when estimating effective thermophysical characteristics of composite materials and thermal contact resistance in two-layer systems.

Computation of aeroelastic characteristics and stress-strained state of parachutes

NASA Astrophysics Data System (ADS)

Dneprov, Igor'v.

The paper presents computation results of the stress-strained state and aeroelastic characteristics of different types of parachutes in the process of their interaction with a flow. Simulation of the aerodynamic part of the aeroelastic problem is based on the discrete vortex method, while the elastic part of the problem is solved by employing either the finite element method, or the finite difference method. The research covers the following problems of the axisymmetric parachutes dynamic aeroelasticity: parachute inflation, forebody influence on the aerodynamic characteristics of the object-parachute system, parachute disreefing, parachute inflation in the presence of the engagement parachute. The paper also presents the solution of the spatial problem of static aeroelasticity for a single-envelope ram-air parachute. Some practical recommendations are suggested.

Healthcare Data Analytics for Parkinson's Disease Patients: A Study of Hospital Cost and Utilization in the United States.

PubMed

Mukherjee, Sunanda; Wu, Huanmei; Jones, Josette

2016-01-01

Parkinson's Disease (PD), a prevalent problem, especially for the aged populations, is a progressive but non-fatal nervous system disorder. PD patients have special motor as well as non-motor symptoms over time. There are several limitations in the study of PD such as unavailability of data, proper diagnosis and treatment methods. These limitations significantly reduce the quality of PD patient life quality, either directly or indirectly. PD also imposes great financial burdens to PD patients and their family. This project aims to analyze the most common reasons for PD patient hospitalization, review complications that occur during inpatient stays, and measure the costs associated with PD patient characteristics. Using the HCUP NIS data, comprehensive data analysis has been performed. The results are customized visualized using Tableau and other software systems. The preliminary findings sheds light into how to improve the life quality of PD patients.

Fast realization of nonrecursive digital filters with limits on signal delay

NASA Astrophysics Data System (ADS)

Titov, M. A.; Bondarenko, N. N.

1983-07-01

Attention is given to the problem of achieving a fast realization of nonrecursive digital filters with the aim of reducing signal delay. It is shown that a realization wherein the impulse characteristic of the filter is divided into blocks satisfies the delay requirements and is almost as economical in terms of the number of multiplications as conventional fast convolution. In addition, the block method leads to a reduction in the needed size of the memory and in the number of additions; the short-convolution procedure is substantially simplified. Finally, the block method facilitates the paralleling of computations owing to the simple transfers between subfilters.

Honor killings in the Middle East and North Africa: a systematic review of the literature.

PubMed

Kulczycki, Andrzej; Windle, Sarah

2011-11-01

A systematic review of the research literature on honor killings in the Middle East and North Africa (MENA) indicates a paucity of studies relative to the presumed magnitude of the problem. Forty articles were reviewed and critically appraised, of which only 9 contained primary data and 11 presented original secondary analyses. Despite a recent increase in published studies, persistent methodological limitations restrict the generalizability of findings. Most studies focus on legal aspects, determinants, and characteristics of victims and perpetrators. Victims are mostly young females murdered by their male kin. Unambiguous evidence of a decline in tolerance of honor killings remains elusive.

Computer games: a double-edged sword?

PubMed

Sun, De-Lin; Ma, Ning; Bao, Min; Chen, Xang-Chuan; Zhang, Da-Ren

2008-10-01

Excessive computer game playing (ECGP) has already become a serious social problem. However, limited data from experimental lab studies are available about the negative consequences of ECGP on players' cognitive characteristics. In the present study, we compared three groups of participants (current ECGP participants, previous ECGP participants, and control participants) on a Multiple Object Tracking (MOT) task. The previous ECGP participants performed significantly better than the control participants, which suggested a facilitation effect of computer games on visuospatial abilities. Moreover, the current ECGP participants performed significantly worse than the previous ECGP participants. This more important finding indicates that ECGP may be related to cognitive deficits. Implications of this study are discussed.

Straight-bladed Darrieus wind turbines - A protagonist's view

NASA Astrophysics Data System (ADS)

Migliore, P. G.

The technology development and market penetration of Darrieus and propeller-type wind turbines is addressed. Important characteristics of competing configurations are compared, and it is claimed that aerodynamic efficiency is not a distinguishing feature. Advantages of the Darrieus machine include omni-directionality and self-limitation, but propeller types require less rotor length per unit swept area. It is argued that the straight-bladed Darrieus is much simpler than the curved-bladed and should be capable of comparable aerodynamic efficiency. Some of the problems of structural design, as well as blade induced drag losses and support-arm counter torque, diminish rapidly as machine size is increased. Taper ratio has similar beneficial effects.

Attention and driving in traumatic brain injury: a question of coping with time-pressure.

PubMed

Brouwer, Wiebo H; Withaar, Frederiec K; Tant, Mark L M; van Zomeren, Adriaan H

2002-02-01

Diffuse and focal traumatic brain injury (TBI) can result in perceptual, cognitive, and motor dysfunction possibly leading to activity limitations in driving. Characteristic dysfunctions for severe diffuse TBI are confronted with function requirements derived from the hierarchical task analysis of driving skill. Specifically, we focus on slow information processing, divided attention, and the development of procedural knowledge. Also the effects of a combination of diffuse and focal dysfunctions, specifically homonymous hemianopia and the dysexecutive syndrome, are discussed. Finally, we turn to problems and challenges with regard to assessment and rehabilitation methods in the areas of driving and fitness to drive.

Study of Interaction of Reinforcement with Concrete by Numerical Methods

NASA Astrophysics Data System (ADS)

Tikhomirov, V. M.; Samoshkin, A. S.

2018-01-01

This paper describes the study of deformation of reinforced concrete. A mathematical model for the interaction of reinforcement with concrete, based on the introduction of a contact layer, whose mechanical characteristics are determined from the experimental data, is developed. The limiting state of concrete is described using the Drucker-Prager theory and the fracture criterion with respect to maximum plastic deformations. A series of problems of the theory of reinforced concrete are solved: stretching of concrete from a central-reinforced prism and pre-stressing of concrete. It is shown that the results of the calculations are in good agreement with the experimental data.

High power, high frequency helix TWT's

NASA Astrophysics Data System (ADS)

Sloley, H. J.; Willard, J.; Paatz, S. R.; Keat, M. J.

The design and performance characteristics of a 34-GHz pulse tube capable of 75 W peak power output at 30 percent duty cycle and a broadband CW tube are presented. Particular attention is given to the engineering problems encountered during the development of the tubes, including the suppression of backward wave oscillation, the design of electron guns for small-diameter high-current beams, and the thermal capability of small helix structures. The discussion also covers the effects of various design parameters and choice of engineering materials on the ultimate practical limit of power and gain at the operating frequencies. Measurements are presented for advanced experimental tubes.

Evaluation of radiometric and geometric characteristics of LANDSAT-D imaging system

NASA Technical Reports Server (NTRS)

Bender, L. U.; Podwysocki, M. H.; Rowan, L.; Salisbury, J. (Principal Investigator)

1983-01-01

Problems, accomplishments, and significant results associated with the evaluation of the LANDSAT-D thematic mapper system are outlined. The higher resolution (over MSS) causes the TM data to approach more closely the quality of high altitude photographs. Thus far, it appears that the data can be used for map inspection and in certain instances for limited map revision. Image maps can be made at a scale of 1:100,000 and perhaps up to 1:62,500. It was also shown that TM data can help locate rocks containing minerals with high hydroxol content, such as clays, gypsum, alunite, and sericite.

Expanded operational capabilities of the Langley Mach 7 Scramjet test facility

NASA Technical Reports Server (NTRS)

Thomas, S. R.; Guy, R. W.

1983-01-01

An experimental research program conducted to expand the operational capabilities of the NASA Langley Mach 7 Scramjet Test Facility is described. Previous scramjet testing in this facility was limited to a single simulated flight condition of Mach 6.9 at an altitude of 115,300 ft. The arc heater research demonstrates the potential of the facility for scramjet testing at simulated flight conditions from Mach 4 (at altitudes from 77,000 to 114,000 ft) to Mach 7 (at latitudes from 108,000 to 149,000 ft). Arc heater electrical characteristics, operational problems, measurements of nitrogen oxide contaminants, and total-temperature profiles are discussed.

Learning from Bacteriophages - Advantages and Limitations of Phage and Phage-Encoded Protein Applications

PubMed Central

Drulis-Kawa, Zuzanna; Majkowska-Skrobek, Grażyna; Maciejewska, Barbara; Delattre, Anne-Sophie; Lavigne, Rob

2012-01-01

The emergence of bacteria resistance to most of the currently available antibiotics has become a critical therapeutic problem. The bacteria causing both hospital and community-acquired infections are most often multidrug resistant. In view of the alarming level of antibiotic resistance between bacterial species and difficulties with treatment, alternative or supportive antibacterial cure has to be developed. The presented review focuses on the major characteristics of bacteriophages and phage-encoded proteins affecting their usefulness as antimicrobial agents. We discuss several issues such as mode of action, pharmacodynamics, pharmacokinetics, resistance and manufacturing aspects of bacteriophages and phage-encoded proteins application. PMID:23305359

Helmet-mounted pilot night vision systems: Human factors issues

NASA Technical Reports Server (NTRS)

Hart, Sandra G.; Brickner, Michael S.

1989-01-01

Helmet-mounted displays of infrared imagery (forward-looking infrared (FLIR)) allow helicopter pilots to perform low level missions at night and in low visibility. However, pilots experience high visual and cognitive workload during these missions, and their performance capabilities may be reduced. Human factors problems inherent in existing systems stem from three primary sources: the nature of thermal imagery; the characteristics of specific FLIR systems; and the difficulty of using FLIR system for flying and/or visually acquiring and tracking objects in the environment. The pilot night vision system (PNVS) in the Apache AH-64 provides a monochrome, 30 by 40 deg helmet-mounted display of infrared imagery. Thermal imagery is inferior to television imagery in both resolution and contrast ratio. Gray shades represent temperatures differences rather than brightness variability, and images undergo significant changes over time. The limited field of view, displacement of the sensor from the pilot's eye position, and monocular presentation of a bright FLIR image (while the other eye remains dark-adapted) are all potential sources of disorientation, limitations in depth and distance estimation, sensations of apparent motion, and difficulties in target and obstacle detection. Insufficient information about human perceptual and performance limitations restrains the ability of human factors specialists to provide significantly improved specifications, training programs, or alternative designs. Additional research is required to determine the most critical problem areas and to propose solutions that consider the human as well as the development of technology.

'Two sides of the coin'--the value of personal continuity to GPs: a qualitative interview study.

PubMed

Ridd, Matthew; Shaw, Alison; Salisbury, Chris

2006-08-01

Continuity is thought to be important to GPs but the values behind this are unknown. To explore the values that doctors working in general practice attach to continuity of patient care and to outline how these values are applied in practice. In-depth qualitative interview with 24 GPs in England. Participants were purposefully sampled according to personal and practice characteristics. Analysis was thematic, drawing on the constant comparative method. The majority of doctors valued doctor-patient, or personal, continuity in their everyday work. It was most valued in patients with serious, complex or psychological problems. GPs believed that through their personal knowledge of the patient and the doctor-patient relationship, personal continuity enabled them to provide higher quality care. However, the benefits of personal continuity were balanced against problems, and GPs identified personal, professional and external constraints that limited its provision. GPs seemed to have resolved the tension between the benefits, limits and constraints they described by accepting an increased reliance on continuity being provided within teams. Personal continuity may offer important benefits to doctors and patients, but we do not know how unique its values are. In particular, it is not clear whether the same benefits can be achieved within teams, the level at which continuity is increasingly being provided. The relative advantages and limits of the different means of delivering continuity need to be better understood, before further policy changes that affect personal continuity are introduced.

Plutonium and uranium determination in environmental samples: combined solvent extraction-liquid scintillation method.

PubMed

McDowell, W J; Farrar, D T; Billings, M R

1974-12-01

A method for the determination of uranium and plutonium by a combined high-resolution liquid scintillation-solvent extraction method is presented. Assuming a sample count equal to background count to be the detection limit, the lower detection limit for these and other alpha-emitting nuclides is 1.0 dpm with a Pyrex sample tube, 0.3 dpm with a quartz sample tube using present detector shielding or 0.02 d.p.m. with pulse-shape discrimination. Alpha-counting efficiency is 100%. With the counting data presented as an alpha-energy spectrum, an energy resolution of 0.2-0.3 MeV peak half-width and an energy identification to +/-0.1 MeV are possible. Thus, within these limits, identification and quantitative determination of a specific alpha-emitter, independent of chemical separation, are possible. The separation procedure allows greater than 98% recovery of uranium and plutonium from solution containing large amounts of iron and other interfering substances. In most cases uranium, even when present in 10(8)-fold molar ratio, may be quantitatively separated from plutonium without loss of the plutonium. Potential applications of this general analytical concept to other alpha-counting problems are noted. Special problems associated with the determination of plutonium in soil and water samples are discussed. Results of tests to determine the pulse-height and energy-resolution characteristics of several scintillators are presented. Construction of the high-resolution liquid scintillation detector is described.

Standardisation of DNA quantitation by image analysis: quality control of instrumentation.

PubMed

Puech, M; Giroud, F

1999-05-01

DNA image analysis is frequently performed in clinical practice as a prognostic tool and to improve diagnosis. The precision of prognosis and diagnosis depends on the accuracy of analysis and particularly on the quality of image analysis systems. It has been reported that image analysis systems used for DNA quantification differ widely in their characteristics (Thunissen et al.: Cytometry 27: 21-25, 1997). This induces inter-laboratory variations when the same sample is analysed in different laboratories. In microscopic image analysis, the principal instrumentation errors arise from the optical and electronic parts of systems. They bring about problems of instability, non-linearity, and shading and glare phenomena. The aim of this study is to establish tools and standardised quality control procedures for microscopic image analysis systems. Specific reference standard slides have been developed to control instability, non-linearity, shading and glare phenomena and segmentation efficiency. Some systems have been controlled with these tools and these quality control procedures. Interpretation criteria and accuracy limits of these quality control procedures are proposed according to the conclusions of a European project called PRESS project (Prototype Reference Standard Slide). Beyond these limits, tested image analysis systems are not qualified to realise precise DNA analysis. The different procedures presented in this work determine if an image analysis system is qualified to deliver sufficiently precise DNA measurements for cancer case analysis. If the controlled systems are beyond the defined limits, some recommendations are given to find a solution to the problem.

A three-dimensional method-of-characteristics solute-transport model (MOC3D)

USGS Publications Warehouse

Konikow, Leonard F.; Goode, D.J.; Hornberger, G.Z.

1996-01-01

This report presents a model, MOC3D, that simulates three-dimensional solute transport in flowing ground water. The model computes changes in concentration of a single dissolved chemical constituent over time that are caused by advective transport, hydrodynamic dispersion (including both mechanical dispersion and diffusion), mixing (or dilution) from fluid sources, and mathematically simple chemical reactions (including linear sorption, which is represented by a retardation factor, and decay). The transport model is integrated with MODFLOW, a three-dimensional ground-water flow model that uses implicit finite-difference methods to solve the transient flow equation. MOC3D uses the method of characteristics to solve the transport equation on the basis of the hydraulic gradients computed with MODFLOW for a given time step. This implementation of the method of characteristics uses particle tracking to represent advective transport and explicit finite-difference methods to calculate the effects of other processes. However, the explicit procedure has several stability criteria that may limit the size of time increments for solving the transport equation; these are automatically determined by the program. For improved efficiency, the user can apply MOC3D to a subgrid of the primary MODFLOW grid that is used to solve the flow equation. However, the transport subgrid must have uniform grid spacing along rows and columns. The report includes a description of the theoretical basis of the model, a detailed description of input requirements and output options, and the results of model testing and evaluation. The model was evaluated for several problems for which exact analytical solutions are available and by benchmarking against other numerical codes for selected complex problems for which no exact solutions are available. These test results indicate that the model is very accurate for a wide range of conditions and yields minimal numerical dispersion for advection-dominated problems. Mass-balance errors are generally less than 10 percent, and tend to decrease and stabilize with time.

Client Engagement Characteristics Associated with Problem Gambling Treatment Outcomes

ERIC Educational Resources Information Center

Dowling, Nicki A.; Cosic, Sanja

2011-01-01

Previous research examining the factors associated with problem gambling treatment outcomes has examined client factors and to date, treatment characteristics, therapist factors, and client-therapist interactions have essentially remained unexplored. This study aimed to investigate how client engagement variables (client-rated therapeutic…

What work schedule characteristics constitute a problem to the individual? A representative study of Swedish shift workers.

PubMed

Åkerstedt, Torbjörn; Kecklund, Göran

2017-03-01

The purpose was to investigate which detailed characteristics of shift schedules that are seen as problems to those exposed. A representative national sample of non-day workers (N = 2031) in Sweden was asked whether they had each of a number of particular work schedule characteristics and, if yes, to what extent this constituted a "big problem in life". It was also inquired whether the individual's work schedules had negative consequences for fatigue, sleep and social life. The characteristic with the highest percentage reporting a big problem was "short notice (<1 month) of a new work schedule" (30.5%), <11 h off between shifts (27.8%), and split duty (>1.5 h break at mid-shift, 27.2%). Overtime (>10 h/week), night work, morning work, day/night shifts showed lower prevalences of being a "big problem". Women indicated more problems in general. Short notice was mainly related to negative social effects, while <11 h off between shifts was related to disturbed sleep, fatigue and social difficulties. It was concluded that schedules involving unpredictable working hours (short notice), short daily rest between shifts, and split duty shifts constitute big problems. The results challenge current views of what aspects of shift work need improvement, and negative social consequences seem more important than those related to health. Copyright © 2016 Elsevier Ltd. All rights reserved.

Applied behavior analysis: behavior management of children with autism spectrum disorders in dental environments.

PubMed

Hernandez, Purnima; Ikkanda, Zachary

2011-03-01

There are a limited number of studies addressing behavior management techniques and procedural modifications that dentists can use to treat people with an autism spectrum disorder (ASD). The authors conducted a search of the dental and behavioral analytic literature to identify management techniques that address problem behaviors exhibited by children with ASDs in dental and other health-related environments. Applied behavior analysis (ABA) is a science in which procedures are based on the principles of behavior through systematic experimentation. Clinicians have used ABA procedures successfully to modify socially significant behaviors of people with ASD. Basic behavior management techniques currently used in dentistry may not encourage people with cognitive and behavioral disabilities, such as ASD, to tolerate simple in-office dental procedures consistently. Instead, dental care providers often are required to use advanced behavior management techniques to complete simple in-office procedures such as prophylaxis, sealant placement and obtaining radiographs. ABA procedures can be integrated in the dental environment to manage problem behaviors often exhibited by children with an ASD. The authors found no evidence-based procedural modifications that address the behavioral characteristics and problematic behaviors of children with an ASD in a dental environment. Further research in this area should be conducted. Knowledge and in-depth understanding of behavioral principles is essential when a dentist is concerned with modifying behaviors. Using ABA procedures can help dentists manage problem behaviors effectively and systematically when performing routine dental treatment. Being knowledgeable about each patient's behavioral characteristics and the parents' level of involvement is important in the successful integration of the procedures and reduction of in-office time.

Implementing a Comprehensive Program for the Prevention of Conduct Problems in Rural Communities: The Fast Track Experience1

PubMed Central

Bierman, Karen L.

2012-01-01

Childhood conduct problems are predictive of a number of serious long-term difficulties (e.g., school failure, delinquent behavior, and mental health problems), making the design of effective prevention programs a priority. The Fast Track Program is a demonstration project currently underway in four demographically diverse areas of the United States, testing the feasibility and effectiveness of a comprehensive, multicomponent prevention program targeting children at risk for conduct disorders. This paper describes some lessons learned about the implementation of this program in a rural area. Although there are many areas of commonality in terms of program needs, program design, and implementation issues in rural and urban sites, rural areas differ from urban areas along the dimensions of geographical dispersion and regionalism, and community stability and insularity. Rural programs must cover a broad geographical area and must be sensitive to the multiple, small and regional communities that constitute their service area. Small schools, homogeneous populations, traditional values, limited recreational, educational and mental health services, and politically conservative climates are all more likely to emerge as characteristics of rural rather than urban sites (Sherman, 1992). These characteristics may both pose particular challenges to the implementation of prevention programs in rural areas, as well as offer particular benefits. Three aspects of program implementation are described in detail: (a) community entry and program initiation in rural areas, (b) the adaptation of program components and service delivery to meet the needs of rural families and schools, and (c) issues in administrative organization of a broadly dispersed tricounty rural prevention program. PMID:9338956

[Comorbidity of substance use with mental disorders].

PubMed

Leonidaki, V; Maliori, M

2009-01-01

This contribution reviews the international literature about dual diagnosis, meaning patients who have simultaneously mental health problems and substance use disorders and discusses epidemiology, clinical characteristics, but primarily etiopathogenesis and different treatment models and interventions. The epidemiological data coming from large-scale studies in the general population in USA, Australia and UK demonstrate the close relationship between mental health problems and substance use disorders. Also, the results from Greek research projects support this close relationship, but their research designs have significant limitations. Multiple and high risks are common in this population, like violent or suicidal behavior, self-harm, physical problems, while they appear less responsive to treatment. Subsequently, different models for etiopathogenesis of dual diagnosis have been suggested: (a) Causal relationship: secondary substance use disorder is subsequent of primary mental illness (self-medication hypothesis, supersenstivity model) or vice versa (alcohol, cannabis, and cocaine use trigger or contribute to development of mental illness). (b) Third factor as the cause of both mental and substance use disorders (genetic factor, neuropathology, traumatic experience, personality characteristics, multiple factors). (c) Comorbidty is due to chance. (d) Each disorder mutually exacerbates the other, regardless the cause. Here, the relationship between alcohol and depression is discussed further as example. The ideas and the research-evidence which support each of these models are presented. Also there is an overview of different treatment models: (a) Consecutive treatment: mental health treatment and substance misuse treatment are provided consecutively. (b) Parallel treatments: the patient attends programs of both mental health and substance use services simultaneously. (c) Integrated treatment: the same clinical team addresses both mental health issues and substance use disorders. The first two models have significant weaknesses due to lack of focus on the interaction of the different disorders or to administrative and managerial barriers. On the other hand, integrated programs appear to overcome these limitations. They use modified interventions provided by the same team in order to address the multiple needs of the patients. Different types of integrated programs are discussed. More pragmatist inter ventions should also be taken into consideration. It is expected that some direction for research and clinical practice to Greece will emerge from this contribution.

[Calls due to suicidal behaviour made to the prehospital, emergency department in Málaga: characteristics and associated factors].

PubMed

Jiménez-Hernández, M; Castro-Zamudio, S; Guzmán Parra, J; Martínez-García, A I; Guillén-Benítez, C; Moreno-Küstner, B

2017-12-29

Suicidal behaviour (fatal and non-fatal) has become a serious public health problem in many countries. The aim of the study was to describe the differential characteristics of emergency calls due to suicidal behaviour made to the Emergency Coordinating Centre (CCUE) in the province of Málaga, in comparison with calls due to physical or psychiatric problems. Retrospective observational study of the calls recorded in the database of the Public Company for Emergency Health during one year. Multivariate logistic regression analyses were carried out including age, gender and the following variables related with the demand: hours of the day, type of day (working days or bank holidays), months of the year and trimesters, number of resources mobilized and types of resolution. The analyses were carried out on 163,331 calls, of which 1,380 calls were due to suicidal behaviour (0.8%), 9,951 for psychiatric reasons (6.1%) and 152,000 for physical reasons (93%). The emergency calls for suicidal behaviour were mainly made by females, between 31-60 years, in the evening and at night, and required transfer to hospital and more than one mobilized resource. Calls due to completed suicide were more frequently made by older men. Calls due to suicidal tendencies predominated over those due to attempted or threatened suicide during the first trimester of the year, while the opposite was the case during the third trimester. The results indicated differential characteristics of suicide calls that are potentially relevant for prevention in spite of the limitations of the present study.

Gambling and problem gambling among young adolescents in Great Britain.

PubMed

Forrest, David; McHale, Ian G

2012-12-01

International evidence suggests that problem gambling tends to be 2-4 times higher among adolescents as among adults and this proves to be true of Great Britain according to the latest adolescent prevalence survey. 8,958 British children (11-15) were surveyed in 201 schools during late 2008 and 2009. The questionnaire included a standard screen, DSM-IV-MR-J, to test for problem gambling. Our regression models explore influences of demographic, home and school characteristics on probabilities (both unconditional and conditional on being a gambler) of a child testing positive for problem gambling. More than 20% of children participated in gambling and, of these, nearly 8% tested positive. Age-group prevalence of problem gambling was 1.9%, compared with 0.6-0.9% in the most recent official adult surveys. Boys were much more likely than girls to gamble and to exhibit symptoms of problem gambling if they did. Generally, home characteristics, particularly parental attitude and example, dominated school characteristics in accounting for risks. Unanticipated findings included significantly elevated probabilities of problem gambling among Asian children and among children who live in a home without siblings. Child income was also a potent predictor of gambling and problem gambling.

Neighborhood characteristics, parenting styles, and children's behavioral problems in Chinese American immigrant families.

PubMed

Lee, Erica H; Zhou, Qing; Ly, Jennifer; Main, Alexandra; Tao, Annie; Chen, Stephen H

2014-04-01

Using data from a socioeconomically diverse sample of Chinese American children (n = 258, aged 6-9 years) in immigrant families, we examined the concurrent relations among neighborhood economic disadvantage and concentration of Asian residents, parenting styles, and Chinese American children's externalizing and internalizing problems. Neighborhood characteristics were measured with 2000 U.S. Census tract-level data, parents (mostly mothers) rated their own parenting styles, and parents and teachers rated children's behavioral problems. Path analysis was conducted to test two hypotheses: (a) parenting styles mediate the relations between neighborhood characteristics and children's behavioral problems, and (b) children's behavioral problems mediate the relations between neighborhood and parenting styles. We found that neighborhood Asian concentration was positively associated with authoritarian parenting, which in turn was associated with Chinese American children's higher externalizing and internalizing problems (by parents' reports). In addition, neighborhood economic disadvantage was positively related to children's externalizing problems (by parents' reports), which in turn predicted lower authoritative parenting. The current results suggest the need to consider multiple pathways in the relations among neighborhood, family, and child adjustment, and they have implications for the prevention and intervention of behavioral problems in Chinese American children.

Does neighborhood social capital buffer the effects of maternal depression on adolescent behavior problems?

PubMed

Delany-Brumsey, Ayesha; Mays, Vickie M; Cochran, Susan D

2014-06-01

Neighborhood characteristics have been shown to impact child well-being. However, it remains unclear how these factors combine with family characteristics to influence child development. The current study helps develop that understanding by investigating how neighborhoods directly impact child and adolescent behavior problems as well as moderate the influence of family characteristics on behavior. Using multilevel linear models, we examined the relationship among neighborhood conditions (poverty and social capital) and maternal depression on child and adolescent behavior problems. The sample included 741 children, age 5–11, and 564 adolescents, age 12–17. Outcomes were internalizing (e.g. anxious/depressed) and externalizing (e.g. aggressive/hyperactive) behavior problems. Neighborhood poverty and maternal depression were both positively associated with behavior problems for children and adolescents. However, while neighborhood social capital was not directly associated with behavior problems, the interaction of social capital and maternal depression was significantly related to behavior problems for adolescents. This interaction showed that living in neighborhoods with higher levels of social capital attenuated the relationship between maternal depression and adolescent behavior problems and confirmed the expectation that raising healthy well-adjusted children depends not only on the family, but also the context in which the family lives.

Assessment of vehicle safety problems for special driving populations

DOT National Transportation Integrated Search

1979-02-16

The report describes vehicle safety problems reported in interviews with 460 physically limited drivers and 41 physically limited non-drivers. The problems reported involved operation of primary and secondary controls, operating other vehicle mechani...

Some New Results in Astrophysical Problems of Nonlinear Theory of Radiative Transfer

NASA Astrophysics Data System (ADS)

Pikichyan, H. V.

2017-07-01

In the interpretation of the observed astrophysical spectra, a decisive role is related to nonlinear problems of radiative transfer, because the processes of multiple interactions of matter of cosmic medium with the exciting intense radiation ubiquitously occur in astrophysical objects, and in their vicinities. Whereas, the intensity of the exciting radiation changes the physical properties of the original medium, and itself was modified, simultaneously, in a self-consistent manner under its influence. In the present report, we show that the consistent application of the principle of invariance in the nonlinear problem of bilateral external illumination of a scattering/absorbing one-dimensional anisotropic medium of finite geometrical thickness allows for simplifications that were previously considered as a prerogative only of linear problems. The nonlinear problem is analyzed through the three methods of the principle of invariance: (i) an adding of layers, (ii) its limiting form, described by differential equations of invariant imbedding, and (iii) a transition to the, so-called, functional equations of the "Ambartsumyan's complete invariance". Thereby, as an alternative to the Boltzmann equation, a new type of equations, so-called "kinetic equations of equivalence", are obtained. By the introduction of new functions - the so-called "linear images" of solution of nonlinear problem of radiative transfer, the linear structure of the solution of the nonlinear problem under study is further revealed. Linear images allow to convert naturally the statistical characteristics of random walk of a "single quantum" or their "beam of unit intensity", as well as widely known "probabilistic interpretation of phenomena of transfer", to the field of nonlinear problems. The structure of the equations obtained for determination of linear images is typical of linear problems.

SwaMURAy - Swapping Memory Unit for Radio Astronomy

NASA Astrophysics Data System (ADS)

Winberg, Simon

2016-03-01

This paper concerns design and performance testing of an HDL module called SwaMURAy that is a configurable, high-speed data sequencing and flow control module serving as an intermediary between data acquisition and subsequent processing stages. While a FIFO suffices for many applications, our case needed a more elaborate solution to overcome legacy design limitations. The SwaMURAy is designed around a system where a block of sampled data is acquired at a fast rate and is then distributed among multiple processing paths to achieve a desired overall processing rate. This architecture provides an effective design pattern around which various software defined radio (SDR) and radio astronomy applications can be built. This solution was partly in response to legacy design restrictions of the SDR platform we used, a difficulty likely experienced by many developers whereby new sampling peripherals are inhibited by legacy characteristics of an underlying reconfigurable platform. Our SDR platform had a planned lifetime of at least five years as a complete redesign and refabrication would be too costly. While the SwaMURAy overcame some performance problems, other problems arose. This paper overviews the SwaMURAy design, performance improvements achieved in an SDR case study, and discusses remaining limitations and workarounds we expect will achieve further improvements.

A Longitudinal Empirical Investigation of the Pathways Model of Problem Gambling.

PubMed

Allami, Youssef; Vitaro, Frank; Brendgen, Mara; Carbonneau, René; Lacourse, Éric; Tremblay, Richard E

2017-12-01

The pathways model of problem gambling suggests the existence of three developmental pathways to problem gambling, each differentiated by a set of predisposing biopsychosocial characteristics: behaviorally conditioned (BC), emotionally vulnerable (EV), and biologically vulnerable (BV) gamblers. This study examined the empirical validity of the Pathways Model among adolescents followed up to early adulthood. A prospective-longitudinal design was used, thus overcoming limitations of past studies that used concurrent or retrospective designs. Two samples were used: (1) a population sample of French-speaking adolescents (N = 1033) living in low socio-economic status (SES) neighborhoods from the Greater Region of Montreal (Quebec, Canada), and (2) a population sample of adolescents (N = 3017), representative of French-speaking students in Quebec. Only participants with at-risk or problem gambling by mid-adolescence or early adulthood were included in the main analysis (n = 180). Latent Profile Analyses were conducted to identify the optimal number of profiles, in accordance with participants' scores on a set of variables prescribed by the Pathways Model and measured during early adolescence: depression, anxiety, impulsivity, hyperactivity, antisocial/aggressive behavior, and drug problems. A four-profile model fit the data best. Three profiles differed from each other in ways consistent with the Pathways Model (i.e., BC, EV, and BV gamblers). A fourth profile emerged, resembling a combination of EV and BV gamblers. Four profiles of at-risk and problem gamblers were identified. Three of these profiles closely resemble those suggested by the Pathways Model.

Flight control systems properties and problems, volume 1

NASA Technical Reports Server (NTRS)

Mcruer, D. T.; Johnston, D. E.

1975-01-01

This volume contains a delineation of fundamental and mechanization-specific flight control characteristics and problems gleaned from many sources and spanning a period of over two decades. It is organized to present and discuss first some fundamental, generic problems of closed-loop flight control systems involving numerator characteristics (quadratic dipoles, non-minimum phase roots, and intentionally introduced zeros). Next the principal elements of the largely mechanical primary flight control system are reviewed with particular emphasis on the influence of nonlinearities. The characteristics and problems of augmentation (damping, stability, and feel) system mechanizations are then dealt with. The particular idiosyncracies of automatic control actuation and command augmentation schemes are stressed, because they constitute the major interfaces with the primary flight control system and an often highly variable vehicle response.

An Assessment of Health Related Quality of Life in a Male Prison Population in Greece Associations with Health Related Characteristics and Characteristics of Detention

PubMed Central

Togas, Constantinos

2014-01-01

Background. Prisoners constitute a group with increased health and social care needs. Although implementing policies that aim at improving outcomes within this population should be a priority area, studies that attempt to assess health outcomes and health related quality of life (HRQoL) in this population are limited. Aim. To assess HRQoL in a prison population in Greece and to explore the relationship between HRQoL and a set of individual sociodemographic and health related characteristics and characteristics of detention. Methods. A cross-sectional study involving 100 male prisoners was conducted in the prison of Corinth in Greece. HRQoL was assessed through the use of the SF-36 and the EQ-5D. Results. The mean physical and mental summary scores of the SF-36 were 55.33 and 46.82, respectively. The EQ-VAS mean score was 76.41%, while the EQ-5D index was 0.72. Multivariate analysis identified a statistical relationship between HRQoL and the conditions of detention, controlling for the effect of sociodemographic characteristics, morbidity, and mental problems. The use of narcotics in particular is significantly associated with lower HRQoL. Conclusions. Implementation of policies that aim at preventing the use of narcotics within the prison environment is expected to contribute to improved HRQoL in this population. PMID:25093161

An assessment of health related quality of life in a male prison population in Greece associations with health related characteristics and characteristics of detention.

PubMed

Togas, Constantinos; Raikou, Maria; Niakas, Dimitris

2014-01-01

Prisoners constitute a group with increased health and social care needs. Although implementing policies that aim at improving outcomes within this population should be a priority area, studies that attempt to assess health outcomes and health related quality of life (HRQoL) in this population are limited. To assess HRQoL in a prison population in Greece and to explore the relationship between HRQoL and a set of individual sociodemographic and health related characteristics and characteristics of detention. A cross-sectional study involving 100 male prisoners was conducted in the prison of Corinth in Greece. HRQoL was assessed through the use of the SF-36 and the EQ-5D. The mean physical and mental summary scores of the SF-36 were 55.33 and 46.82, respectively. The EQ-VAS mean score was 76.41%, while the EQ-5D index was 0.72. Multivariate analysis identified a statistical relationship between HRQoL and the conditions of detention, controlling for the effect of sociodemographic characteristics, morbidity, and mental problems. The use of narcotics in particular is significantly associated with lower HRQoL. Implementation of policies that aim at preventing the use of narcotics within the prison environment is expected to contribute to improved HRQoL in this population.

Task-based optimization of flip angle for fibrosis detection in T1-weighted MRI of liver

PubMed Central

Brand, Jonathan F.; Furenlid, Lars R.; Altbach, Maria I.; Galons, Jean-Philippe; Bhattacharyya, Achyut; Sharma, Puneet; Bhattacharyya, Tulshi; Bilgin, Ali; Martin, Diego R.

2016-01-01

Abstract. Chronic liver disease is a worldwide health problem, and hepatic fibrosis (HF) is one of the hallmarks of the disease. The current reference standard for diagnosing HF is biopsy followed by pathologist examination; however, this is limited by sampling error and carries a risk of complications. Pathology diagnosis of HF is based on textural change in the liver as a lobular collagen network that develops within portal triads. The scale of collagen lobules is characteristically in the order of 1 to 5 mm, which approximates the resolution limit of in vivo gadolinium-enhanced magnetic resonance imaging in the delayed phase. We use MRI of formalin-fixed human ex vivo liver samples as phantoms that mimic the textural contrast of in vivo Gd-MRI. We have developed a local texture analysis that is applied to phantom images, and the results are used to train model observers to detect HF. The performance of the observer is assessed with the area-under-the-receiver–operator-characteristic curve (AUROC) as the figure-of-merit. To optimize the MRI pulse sequence, phantoms were scanned with multiple times at a range of flip angles. The flip angle that was associated with the highest AUROC was chosen as optimal for the task of detecting HF. PMID:27446971

Pushing the Limits: 3D Layer-by-Layer-Assembled Composites for Cathodes with 160 C Discharge Rates.

PubMed

Mo, Runwei; Tung, Siu On; Lei, Zhengyu; Zhao, Guangyu; Sun, Kening; Kotov, Nicholas A

2015-05-26

Deficiencies of cathode materials severely limit cycling performance and discharge rates of Li batteries. The key problem is that cathode materials must combine multiple properties: high lithium ion intercalation capacity, electrical/ionic conductivity, porosity, and mechanical toughness. Some materials revealed promising characteristics in a subset of these properties, but attaining the entire set of often contrarian characteristics requires new methods of materials engineering. In this paper, we report high surface area 3D composite from reduced graphene oxide loaded with LiFePO4 (LFP) nanoparticles made by layer-by-layer assembly (LBL). High electrical conductivity of the LBL composite is combined with high ionic conductivity, toughness, and low impedance. As a result of such materials properties, reversible lithium storage capacity and Coulombic efficiency were as high as 148 mA h g(-1) and 99%, respectively, after 100 cycles at 1 C. Moreover, these composites enabled unusually high reversible charge-discharge rates up to 160 C with a storage capacity of 56 mA h g(-1), exceeding those of known LFP-based cathodes, some of them by several times while retaining high content of active cathode material. The study demonstrates that LBL-assembled composites enable resolution of difficult materials engineering tasks.

A longitudinal study of child sleep in high and low risk families: relationship to early maternal settling strategies and child psychological functioning.

PubMed

Sheridan, Andrew; Murray, Lynne; Cooper, Peter J; Evangeli, Michael; Byram, Victoria; Halligan, Sarah L

2013-03-01

To investigate whether sleep disturbances previously found to characterise high risk infants: (a) persist into childhood; (b) are influenced by early maternal settling strategies and (c) predict cognitive and emotional/behavioural functioning. Mothers experiencing high and low levels of psychosocial adversity (risk) were recruited antenatally and longitudinally assessed with their children. Mothers completed measures of settling strategies and infant sleep postnatally, and at 12 and 18 months, infant age. At five years, child sleep characteristics were measured via an actigraphy and maternal report; IQ and child adjustment were also assessed. Sleep disturbances observed in high-risk infants persisted at five years. Maternal involvement in infant settling was greater in high risk mothers, and predicted less optimal sleep at five years. Poorer five year sleep was associated with concurrent child anxiety/depression and aggression, but there was limited evidence for an influence of early sleep problems. Associations between infant/child sleep characteristics and IQ were also limited. Early maternal over-involvement in infant settling is associated with less optimal sleep in children, which in turn, is related to child adjustment. The findings highlight the importance of supporting parents in the early development of good settling practices, particularly in high-risk populations. Copyright © 2012 Elsevier B.V. All rights reserved.

Social capital, friendship networks, and youth unemployment.

PubMed

Hällsten, Martin; Edling, Christofer; Rydgren, Jens

2017-01-01

Youth unemployment is a contemporary social problem in many societies. Youths often have limited access to information about jobs and limited social influence, yet little is known about the relationship between social capital and unemployment risk among youth. We study the effect of social capital on unemployment risk in a sample of 19 year olds of Swedish, Iranian, and Yugoslavian origin living in Sweden (N = 1590). We distinguish between two dimensions of social capital: occupational contact networks and friendship networks. First, ego's unemployment is found to be strongly associated with friends' unemployment among individuals of Yugoslavian origins and individuals of Swedish origin, but not Iranian origin. Second, occupational contact networks reduce unemployment risks for all groups, but especially so for Iranians. The effect sizes of the two dimensions are similar and substantial: going from low to high values on these measures is associated with a difference of some 60-70 percent relative difference in unemployment risk. The findings are robust to a number of different model specifications, including a rich set of social origin controls, personality traits, educational performance, friends' characteristics, and friendship network characteristics, as well as controls for geographical employment patterns. A sensitivity simulation shows that homogeneity bias need to be very strong to explain away the effect. Copyright © 2016 Elsevier Inc. All rights reserved.

Study of the Mechanism of Irreversible Adsorption of Single-Walled Carbon Nanotubes to Sephacryl Hydrogel

NASA Astrophysics Data System (ADS)

Rolsma, Caleb

As a class of carbon-based nanomaterials, single-walled carbon nanotubes (SWNT) have many structural variations, called chiralities, each with different properties. Many potential applications of SWNT require the properties of a single chirality, but current synthesis methods can only produce single chiralities at prohibitive costs, or mixtures of chiralities at more affordable prices. Post-synthesis chirality separations provide a solution to this problem, and hydrogel separations are one such method. Despite much work in this field, the underlying interactions between SWNT and hydrogel are not fully understood. During separation, large quantities of SWNT are irretrievably lost due to irreversible adsorption to the hydrogel, posing a major problem to separation efficiency, while also offering an interesting scientific problem concerning the interaction of SWNT with hydrogels and surfactants. This thesis explores the problem of irreversible adsorption, offering an explanation for the process from a mechanistic viewpoint, opening new ways for improvement in separation. In brief, this work concludes adsorption follows three pathways, two of which lead to irreversible adsorption, both mediated by the presence of surfactants and limited by characteristics of the hydrogel surface. These findings stand to increase the general understanding of hydrogel SWNT separations, leading to improvements in separation, and bringing the research field closer to the many potential applications of single-chirality SWNT.

Biopsychosocial characteristics of community-dwelling older adults with limited ability to walk one-quarter of a mile.

PubMed

Hardy, Susan E; McGurl, David J; Studenski, Stephanie A; Degenholtz, Howard B

2010-03-01

To establish nationally representative estimates of the prevalence of self-reported difficulty and inability of older adults to walk one-quarter of a mile and to identify the characteristics independently associated with difficulty or inability to walk one-quarter of a mile. Cross-sectional analysis of data from the 2003 Cost and Use Medicare Current Beneficiary Survey. Community. Nine thousand five hundred sixty-three community-dwelling Medicare beneficiaries aged 65 and older, representing an estimated total population of 34.2 million older adults. Self-reported ability to walk one-quarter of a mile, sociodemographics, chronic conditions, body mass index, smoking, functional status. In 2003, an estimated 9.5 million older Medicare beneficiaries had difficulty walking one-quarter of a mile, and 5.9 million were unable to do so. Of the 20.2 million older adults with no difficulty in activities of daily living (ADLs) or instrumental activities of daily living (IADLs), an estimated 4.3 million (21%) had limited ability to walk one-quarter of a mile. Having difficulty or being unable to walk one-quarter of a mile was independently associated with older age, female sex, non-Hispanic ethnicity, lower educational level, Medicaid entitlement, most chronic medical conditions, current smoking, and being overweight or obese. Almost half of older adults and 20% of those reporting no ADL or IADL limitations report limited ability to walk one-quarter of a mile. For functionally independent older adults, reported ability to walk one-quarter of a mile can identify vulnerable older adults with greater medical problems and fewer resources and may be a valuable clinical marker in planning their care. Future work is needed to determine the association between ability to walk one-quarter of a mile walk and subsequent functional decline and healthcare use.

Recovery of nonwetting characteristics by surface modification of gallium-based liquid metal droplets using hydrochloric acid vapor.

PubMed

Kim, Daeyoung; Thissen, Peter; Viner, Gloria; Lee, Dong-Weon; Choi, Wonjae; Chabal, Yves J; Lee, Jeong-Bong J B

2013-01-01

The applicability of gallium-based liquid metal alloy has been limited by the oxidation problem. In this paper, we report a simple method to remove the oxide layer on the surface of such alloy to recover its nonwetting characteristics, using hydrochloric acid (HCl) vapor. Through the HCl vapor treatment, we successfully restored the nonwetting characteristics of the alloy and suppressed its viscoelasticity. We analyzed the change of surface chemistry before and after the HCl vapor treatment using X-ray photoelectron spectroscopy (XPS) and low-energy ion-scattering spectroscopy (LEIS). Results showed that the oxidized surface of the commercial gallium-based alloy Galinstan (Ga(2)O(3) and Ga(2)O) was replaced with InCl(3) and GaCl(3) after the treatment. Surface tension and static contact angle on a Teflon-coated glass of the HCl-vapor-treated Galinstan were measured to be 523.8 mN/m and 152.5°. A droplet bouncing test was successfully carried out to demonstrate the nonwetting characteristics of the HCl-vapor-treated Galinstan. Finally, the stability of the transformed surface of the HCl-vapor-treated Galinstan was investigated by measuring the contact angle and LEIS spectra after reoxidation in an ambient environment.

What you should know about land-cover data

USGS Publications Warehouse

Gallant, Alisa L.

2009-01-01

Wildlife biologists are using land-characteristics data sets for a variety of applications. Many kinds of landscape variables have been characterized and the resultant data sets or maps are readily accessible. Often, too little consideration is given to the accuracy or traits of these data sets, most likely because biologists do not know how such data are compiled and rendered, or the potential pitfalls that can be encountered when applying these data. To increase understanding of the nature of land-characteristics data sets, I introduce aspects of source information and data-handling methodology that include the following: ambiguity of land characteristics; temporal considerations and the dynamic nature of the landscape; type of source data versus landscape features of interest; data resolution, scale, and geographic extent; data entry and positional problems; rare landscape features; and interpreter variation. I also include guidance for determining the quality of land-characteristics data sets through metadata or published documentation, visual clues, and independent information. The quality or suitability of the data sets for wildlife applications may be improved with thematic or spatial generalization, avoidance of transitional areas on maps, and merging of multiple data sources. Knowledge of the underlying challenges in compiling such data sets will help wildlife biologists to better assess the strengths and limitations and determine how best to use these data.

The Characteristics, Benefits, and Problems Associated with Implementing DBAE.

ERIC Educational Resources Information Center

Day, Michael D.

1989-01-01

To investigate the characteristics, benefits, and problems associated with implementing Discipline-Based Art Education, the author accompanies two hypothetical secondary school principals on a visit to a high school involved in DBAE. The tour highlights state graduation requirements, instructional materials, and student evaluation methods related…

Limit order placement as an utility maximization problem and the origin of power law distribution of limit order prices

NASA Astrophysics Data System (ADS)

Lillo, F.

2007-02-01

I consider the problem of the optimal limit order price of a financial asset in the framework of the maximization of the utility function of the investor. The analytical solution of the problem gives insight on the origin of the recently empirically observed power law distribution of limit order prices. In the framework of the model, the most likely proximate cause of this power law is a power law heterogeneity of traders' investment time horizons.

Co-Occurring Problems of Early Onset Persistent, Childhood Limited, and Adolescent Onset Conduct Problem Youth

ERIC Educational Resources Information Center

Barker, Edward D.; Oliver, Bonamy R.; Maughan, Barbara

2010-01-01

Background: It is increasingly recognized that youth who follow early onset persistent (EOP), childhood limited (CL) and adolescent onset (AO) trajectories of conduct problems show somewhat varying patterns of risk (in childhood) and adjustment problems (in adolescence and adulthood). Little, however, is known about how other adjustment problems…

Students' Dilemmas in Reaction Stoichiometry Problem Solving: Deducing the Limiting Reagent in Chemical Reactions

ERIC Educational Resources Information Center

Chandrasegaran, A. L.; Treagust, David F.; Waldrip, Bruce G.; Chandrasegaran, Antonia

2009-01-01

A qualitative case study was conducted to investigate the understanding of the limiting reagent concept and the strategies used by five Year 11 students when solving four reaction stoichiometry problems. Students' written problem-solving strategies were studied using the think-aloud protocol during problem-solving, and retrospective verbalisations…

Limitations in the Prediction of Mass Violence: Cautionary Tales.

PubMed

Archer, Robert P

2018-06-21

The incidents of mass violence that have occurred in the United States have been deeply disturbing to the public as well as to mental health professionals. The public, the media, as well as our patients, family members, and friends have reached out to mental health professionals in the hope that we can provide an understanding of these events that might serve to reduce their frequency in the future. This article explores how we can best respond to these requests, including the current limitations of psychologists in the prediction of mass violence. Two incidents of mass violence are used to illustrate these issues. The first is a review of the investigation of the explosion on the U.S.S. Iowa in April 1989 that resulted in the deaths of 47 seamen. The second incident used for illustration purposes will be the University of Texas Clock Tower shootings that occurred in August 1968. This article discusses the reliability and validity problems inherent in retrospective reviews of the personality characteristics of perpetrators, and the limitations imposed by base-rate issues in the prediction of mass violence.

Classification of prostate cancer grade using temporal ultrasound: in vivo feasibility study

NASA Astrophysics Data System (ADS)

Ghavidel, Sahar; Imani, Farhad; Khallaghi, Siavash; Gibson, Eli; Khojaste, Amir; Gaed, Mena; Moussa, Madeleine; Gomez, Jose A.; Siemens, D. Robert; Leveridge, Michael; Chang, Silvia; Fenster, Aaron; Ward, Aaron D.; Abolmaesumi, Purang; Mousavi, Parvin

2016-03-01

Temporal ultrasound has been shown to have high classification accuracy in differentiating cancer from benign tissue. In this paper, we extend the temporal ultrasound method to classify lower grade Prostate Cancer (PCa) from all other grades. We use a group of nine patients with mostly lower grade PCa, where cancerous regions are also limited. A critical challenge is to train a classifier with limited aggressive cancerous tissue compared to low grade cancerous tissue. To resolve the problem of imbalanced data, we use Synthetic Minority Oversampling Technique (SMOTE) to generate synthetic samples for the minority class. We calculate spectral features of temporal ultrasound data and perform feature selection using Random Forests. In leave-one-patient-out cross-validation strategy, an area under receiver operating characteristic curve (AUC) of 0.74 is achieved with overall sensitivity and specificity of 70%. Using an unsupervised learning approach prior to proposed method improves sensitivity and AUC to 80% and 0.79. This work represents promising results to classify lower and higher grade PCa with limited cancerous training samples, using temporal ultrasound.

The Race Idea in Reproductive Technologies: Beyond Epistemic Scientism and Technological Mastery.

PubMed

Russell, Camisha

2015-12-01

This paper explores the limitations of epistemic scientism for understanding the role the concept of race plays in assisted reproductive technology (ART) practices. Two major limitations centre around the desire to use scientific knowledge to bring about social improvement. In the first case, undue focus is placed on debunking the scientific reality of racial categories and characteristics. The alternative to this approach is to focus instead on the way the race idea functions in ART practices. Doing so reveals how the race idea (1) helps to define the reproductive "problems" different groups of women are experiencing and to dictate when and how they should be "helped"; (2) helps to resolve tensions about who should be considered the real parents of children produced by reproductive technologies; and (3) is used to limit ART use where that use threatens to denaturalize the very sociopolitical landscape the race idea has created. In the second case, scientific knowledge regarding reproduction is thought to call for technological control over that reproduction. This leads to an overemphasis on personal responsibility and a depoliticization of racialized social inequalities.

Pushing the plasmonic imaging nanolithography to nano-manufacturing

NASA Astrophysics Data System (ADS)

Gao, Ping; Li, Xiong; Zhao, Zeyu; Ma, Xiaoliang; Pu, Mingbo; Wang, Changtao; Luo, Xiangang

2017-12-01

Suffering from the so-called diffraction limit, the minimum resolution of conventional photolithography is limited to λ / 2 or λ / 4, where λ is the incident wavelength. The physical mechanism of this limit lies at the fact that the evanescent waves that carry subwavelength information of the object decay exponentially in a medium, and cannot reach the image plane. Surface plasmons (SPs) are non-radiative electromagnetic waves that propagate along the interface between metal and dielectric, which exhibits unique sub-diffraction optical characteristics. In recent years, benefiting from SPs' features, researchers have proposed a variety of plasmonic lithography methods in the manner of interference, imaging and direct writing, and have demonstrated that sub-diffraction resolution could be achieved by theoretical simulations or experiments. Among the various plasmonic lithography modes, plasmonic imaging lithography seems to be of particular importance for applications due to its compatibility with conventional lithography. Recent results show that the half pitch of nanograting can be shrinked down to 22 nm and even 16 nm. This paper will give an overview of research progress, representative achievements of plasmonic imaging lithography, the remained problems and outlook of further developments.

Comparison between Hydrogen, Methane and Ethylene Fuels in a 3-D Scramjet at Mach 8

DTIC Science & Technology

2016-06-24

characteristics in air. The disadvantage of hydrogen is its low density, which is a particular problem for small vehicles with significant internal...characteristics in air. The disadvantage of hydrogen is its low density, which is a particular problem for small vehicles with significant internal volume...The low energy per unit volume of gaseous hydrogen, however, is a significant problem for small vehicles with internal volume constraints, in addition

Buckling and Damage Resistance of Transversely-Loaded Composite Shells

NASA Technical Reports Server (NTRS)

Wardle, Brian L.

1998-01-01

Experimental and numerical work was conducted to better understand composite shell response to transverse loadings which simulate damage-causing impact events. The quasi-static, centered, transverse loading response of laminated graphite/epoxy shells in a [+/-45(sub n)/O(sub n)](sub s) layup having geometric characteristics of a commercial fuselage are studied. The singly-curved composite shell structures are hinged along the straight circumferential edges and are either free or simply supported along the curved axial edges. Key components of the shell response are response instabilities due to limit-point and/or bifurcation buckling. Experimentally, deflection-controlled shell response is characterized via load-deflection data, deformation-shape evolutions, and the resulting damage state. Finite element models are used to study the kinematically nonlinear shell response, including bifurcation, limit-points, and postbuckling. A novel technique is developed for evaluating bifurcation from nonlinear prebuckling states utilizing asymmetric spatial discretization to introduce numerical perturbations. Advantages of the asymmetric meshing technique (AMT) over traditional techniques include efficiency, robustness, ease of application, and solution of the actual (not modified) problems. The AMT is validated by comparison to traditional numerical analysis of a benchmark problem and verified by comparison to experimental data. Applying the technique, bifurcation in a benchmark shell-buckling problem is correctly identified. Excellent agreement between the numerical and experimental results are obtained for a number of composite shells although predictive capability decreases for stiffer (thicker) specimens which is attributed to compliance of the test fixture. Restraining the axial edge (simple support) has the effect of creating a more complex response which involves unstable bifurcation, limit-point buckling, and dynamic collapse. Such shells were noted to bifurcate into asymmetric deformation modes but were undamaged during testing. Shells in this study which were damaged were not observed to bifurcate. Thus, a direct link between bifurcation and atypical damage could not be established although the mechanism (bifurcation) was identified. Recommendations for further work in these related areas are provided and include extensions of the AMT to other shell geometries and structural problems.

Characteristics of the patient with an ostomy.

PubMed

Pittman, Joyce

2011-01-01

Complications following intestinal and urinary diversion (OSTOMY) surgery are a significant problem for many individuals. Patient characteristics or risk factors have been associated with the development of ostomy complications, but research in this area is limited. To examine the demographic and clinical characteristics of new ostomy patients. Descriptive, cross-sectional study. A convenience sample of 144 new ostomy patients was recruited from a large midwest urban level i trauma teaching hospital system. A descriptive, cross-sectional design was used to examine the demographic and clinical characteristics in persons with a new ostomy. demographic and clinical characteristics included were age, gender, disposition, diagnosis, ostomy type, type of procedure (emergent or elective), stoma type (temporary or permanent), technique of stoma creation (loop or end), stoma site marked preoperatively, body type, stoma height, and complicating factors. Data were collected through a medical record review and direct observation by the WOC nurse. Significant differences were found among demographic and clinical characteristics and ostomy type and disposition. Age, type of procedure, reason for surgery, stoma type, stoma site marking, and complicating factors were significantly different by ostomy type. The majority of stomas were not marked preoperatively (67%). Sixty-eight percent of persons with a stoma above skin level versus 38% with a stoma below skin level were discharged to their home. Statistically significant relationships were found among disposition and type of procedure (P = .036), stoma height (P = .003), reason for surgery (P = .000), and age (P = .005). This study provides additional information regarding specific patient characteristics (demographic and clinical) and their relationship to ostomy type and disposition.

The Characteristic of the Process of Students' Metacognition in Solving Calculus Problems

ERIC Educational Resources Information Center

Purnomo, Dwi; Nusantara, Toto; Subanji; Rahardjo, Swasono

2017-01-01

This article is the result of research aims to describe the patterns and characteristics of the process of metacognition student of mathematics in solving calculus problems. Description was done by looking at changes in "awareness," "evaluation," and "regulation" as components of metacognition. The changes in…

Testing for scale-invariance in extreme events, with application to earthquake occurrence

NASA Astrophysics Data System (ADS)

Main, I.; Naylor, M.; Greenhough, J.; Touati, S.; Bell, A.; McCloskey, J.

2009-04-01

We address the generic problem of testing for scale-invariance in extreme events, i.e. are the biggest events in a population simply a scaled model of those of smaller size, or are they in some way different? Are large earthquakes for example ‘characteristic', do they ‘know' how big they will be before the event nucleates, or is the size of the event determined only in the avalanche-like process of rupture? In either case what are the implications for estimates of time-dependent seismic hazard? One way of testing for departures from scale invariance is to examine the frequency-size statistics, commonly used as a bench mark in a number of applications in Earth and Environmental sciences. Using frequency data however introduces a number of problems in data analysis. The inevitably small number of data points for extreme events and more generally the non-Gaussian statistical properties strongly affect the validity of prior assumptions about the nature of uncertainties in the data. The simple use of traditional least squares (still common in the literature) introduces an inherent bias to the best fit result. We show first that the sampled frequency in finite real and synthetic data sets (the latter based on the Epidemic-Type Aftershock Sequence model) converge to a central limit only very slowly due to temporal correlations in the data. A specific correction for temporal correlations enables an estimate of convergence properties to be mapped non-linearly on to a Gaussian one. Uncertainties closely follow a Poisson distribution of errors across the whole range of seismic moment for typical catalogue sizes. In this sense the confidence limits are scale-invariant. A systematic sample bias effect due to counting whole numbers in a finite catalogue makes a ‘characteristic'-looking type extreme event distribution a likely outcome of an underlying scale-invariant probability distribution. This highlights the tendency of ‘eyeball' fits unconsciously (but wrongly in this case) to assume Gaussian errors. We develop methods to correct for these effects, and show that the current best fit maximum likelihood regression model for the global frequency-moment distribution in the digital era is a power law, i.e. mega-earthquakes continue to follow the Gutenberg-Richter trend of smaller earthquakes with no (as yet) observable cut-off or characteristic extreme event. The results may also have implications for the interpretation of other time-limited geophysical time series that exhibit power-law scaling.

Associations between skin barrier characteristics, skin conditions and health of aged nursing home residents: a multi-center prevalence and correlational study.

PubMed

Hahnel, Elisabeth; Blume-Peytavi, Ulrike; Trojahn, Carina; Kottner, Jan

2017-11-13

Geriatric patients are affected by a range of skin conditions and dermatological diseases, functional limitations and chronic diseases. Skin problems are highly prevalent in elderly populations. Aim of this study was to investigate possible associations between health, functional and cutaneous variables in aged long-term care residents. This observational, cross-sectional, descriptive prevalence study was conducted in a random sample of 10 institutional long-term care facilities in Berlin. In total, n = 223 residents were included. Demographic and functional characteristics, xerosis cutis, incontinence associated dermatitis, pressure ulcers and skin tears were assessed. Stratum corneum hydration, transepidermal water loss, skin surface pH and skin temperature were measured. Data analysis was descriptive and explorative. To explore possible bivariate associations, a correlation matrix was created. The correlation matrix was also used to detect possible collinearity in the subsequent regression analyses. Mean age (n = 223) was 83.6 years, 67.7% were female. Most residents were affected by xerosis cutis (99.1%; 95% CI: 97.7% - 100.0%). The prevalence of pressure ulcers was 9.0% (95% CI: 5.0% - 13.0%), of incontinence associated dermatitis 35.4% (95% CI: 29.9% - 42.2%) and of skin tears 6.3% (95% CI: 3.2% - 9.5%). Biophysical skin parameters were not associated with overall care dependency, but with age and skin dryness. In general, skin dryness and measured skin barrier parameters were associated between arms and legs indicating similar overall skin characteristics of the residents. Prevalence of xerosis cutis, pressure ulcers and skin tears were high, indicating the load of these adverse skin conditions in this population. Only few associations of demographic characteristics, skin barrier impairments and the occurrence of dry skin, pressure ulcers, skin tears and incontinence-associated dermatitis have been detected, that might limit the diagnostic value of skin barrier parameters in this population. Overall, the measured skin barrier parameters seem to have limited diagnostic value for the reported skin conditions except xerosis cutis. This study is registered at https://clinicaltrials.gov/ct2/show/NCT02216526 . Registration date: 8th November 2014.

Food preferences and factors influencing food selectivity for children with autism spectrum disorders.

PubMed

Schreck, Kimberly A; Williams, Keith

2006-01-01

Although clinicians and parents widely accept that children with autism spectrum disorder exhibit more feeding problems than their typically developing peers, little information is available concerning the characteristic food items accepted by these children or the possible factors contributing to these feeding problems. This article used an informant-based questionnaire to survey parents of children with autism spectrum disorders (N=138) to determine: (a) the types of feeding problems their children typically exhibit, (b) the food items their children prefer, (c) the relationship of feeding problems to family eating preferences, and (d) the relationship of the diagnostic characteristics of autism to feeding behavior. Results indicated that the children preferred fewer types of food items within groups than their families; however, family food preferences appeared to influence food selection more than the diagnostic characteristics of autism.

Toward a dose reduction strategy using model-based reconstruction with limited-angle tomosynthesis

NASA Astrophysics Data System (ADS)

Haneda, Eri; Tkaczyk, J. E.; Palma, Giovanni; Iordache, Rǎzvan; Zelakiewicz, Scott; Muller, Serge; De Man, Bruno

2014-03-01

Model-based iterative reconstruction (MBIR) is an emerging technique for several imaging modalities and appli- cations including medical CT, security CT, PET, and microscopy. Its success derives from an ability to preserve image resolution and perceived diagnostic quality under impressively reduced signal level. MBIR typically uses a cost optimization framework that models system geometry, photon statistics, and prior knowledge of the recon- structed volume. The challenge of tomosynthetic geometries is that the inverse problem becomes more ill-posed due to the limited angles, meaning the volumetric image solution is not uniquely determined by the incom- pletely sampled projection data. Furthermore, low signal level conditions introduce additional challenges due to noise. A fundamental strength of MBIR for limited-views and limited-angle is that it provides a framework for constraining the solution consistent with prior knowledge of expected image characteristics. In this study, we analyze through simulation the capability of MBIR with respect to prior modeling components for limited-views, limited-angle digital breast tomosynthesis (DBT) under low dose conditions. A comparison to ground truth phantoms shows that MBIR with regularization achieves a higher level of fidelity and lower level of blurring and streaking artifacts compared to other state of the art iterative reconstructions, especially for high contrast objects. The benefit of contrast preservation along with less artifacts may lead to detectability improvement of microcalcification for more accurate cancer diagnosis.

Spectral-element simulations of wave propagation in complex exploration-industry models: Mesh generation and forward simulations

NASA Astrophysics Data System (ADS)

Nissen-Meyer, T.; Luo, Y.; Morency, C.; Tromp, J.

2008-12-01

Seismic-wave propagation in exploration-industry settings has seen major research and development efforts for decades, yet large-scale applications have often been limited to 2D or 3D finite-difference, (visco- )acoustic wave propagation due to computational limitations. We explore the possibility of including all relevant physical signatures in the wavefield using the spectral- element method (SPECFEM3D, SPECFEM2D), thereby accounting for acoustic, (visco-)elastic, poroelastic, anisotropic wave propagation in meshes which honor all crucial discontinuities. Mesh design is the crux of the problem, and we use CUBIT (Sandia Laboratories) to generate unstructured quadrilateral 2D and hexahedral 3D meshes for these complex background models. While general hexahedral mesh generation is an unresolved problem, we are able to accommodate most of the relevant settings (e.g., layer-cake models, salt bodies, overthrusting faults, and strong topography) with respectively tailored workflows. 2D simulations show localized, characteristic wave effects due to these features that shall be helpful in designing survey acquisition geometries in a relatively economic fashion. We address some of the fundamental issues this comprehensive modeling approach faces regarding its feasibility: Assessing geological structures in terms of the necessity to honor the major structural units, appropriate velocity model interpolation, quality control of the resultant mesh, and computational cost for realistic settings up to frequencies of 40 Hz. The solution to this forward problem forms the basis for subsequent 2D and 3D adjoint tomography within this context, which is the subject of a companion paper.

Mind over matter? I: philosophical aspects of the mind-brain problem.

PubMed

Schimmel, P

2001-08-01

To conceptualize the essence of the mind-body or mind-brain problem as one of metaphysics rather than science, and to propose a formulation of the problem in the context of current scientific knowledge and its limitations. The background and conceptual parameters of the mind-body problem are delineated, and the limitations of brain research in formulating a solution identified. The problem is reformulated and stated in terms of two propositions. These constitute a 'double aspect theory'. The problem appears to arise as a consequence of the conceptual limitations of the human mind, and hence remains essentially a metaphysical one. A 'double aspect theory' recognizes the essential unity of mind and brain, while remaining consistent with the dualism inherent in human experience.

Identification of dynamic characteristics of flexible rotors as dynamic inverse problem

NASA Technical Reports Server (NTRS)

Roisman, W. P.; Vajingortin, L. D.

1991-01-01

The problem of dynamic and balancing of flexible rotors were considered, which were set and solved as the problem of the identification of flexible rotor systems, which is the same as the inverse problem of the oscillation theory dealing with the task of the identifying the outside influences and system parameters on the basis of the known laws of motion. This approach to the problem allows the disclosure the picture of disbalances throughout the rotor-under-test (which traditional methods of flexible rotor balancing, based on natural oscillations, could not provide), and identify dynamic characteristics of the system, which correspond to a selected mathematical model. Eventually, various methods of balancing were developed depending on the special features of the machines as to their design, technology, and operation specifications. Also, theoretical and practical methods are given for the flexible rotor balancing at far from critical rotation frequencies, which does not necessarily require the knowledge forms of oscillation, dissipation, and elasticity and inertia characteristics, and to use testing masses.

Do job demands and job control affect problem-solving?

PubMed

Bergman, Peter N; Ahlberg, Gunnel; Johansson, Gun; Stoetzer, Ulrich; Aborg, Carl; Hallsten, Lennart; Lundberg, Ingvar

2012-01-01

The Job Demand Control model presents combinations of working conditions that may facilitate learning, the active learning hypothesis, or have detrimental effects on health, the strain hypothesis. To test the active learning hypothesis, this study analysed the effects of job demands and job control on general problem-solving strategies. A population-based sample of 4,636 individuals (55% women, 45% men) with the same job characteristics measured at two times with a three year time lag was used. Main effects of demands, skill discretion, task authority and control, and the combined effects of demands and control were analysed in logistic regressions, on four outcomes representing general problem-solving strategies. Those reporting high on skill discretion, task authority and control, as well as those reporting high demand/high control and low demand/high control job characteristics were more likely to state using problem solving strategies. Results suggest that working conditions including high levels of control may affect how individuals cope with problems and that workplace characteristics may affect behaviour in the non-work domain.

Does Neighborhood Social Capital Buffer the Effects of Maternal Depression on Adolescent Behavior Problems?

PubMed Central

Mays, Vickie M.; Cochran, Susan D.

2014-01-01

Neighborhood characteristics have been shown to impact child well-being. However, it remains unclear how these factors combine with family characteristics to influence child development. The current study helps develop that understanding by investigating how neighborhoods directly impact child and adolescent behavior problems as well as moderate the influence of family characteristics on behavior. Using multilevel linear models, we examined the relationship among neighborhood conditions (poverty and social capital) and maternal depression on child and adolescent behavior problems. The sample included 741 children, age 5–11, and 564 adolescents, age 12–17. Outcomes were internalizing (e.g. anxious/depressed) and externalizing (e.g. aggressive/hyperactive) behavior problems. Neighborhood poverty and maternal depression were both positively associated with behavior problems for children and adolescents. However, while neighborhood social capital was not directly associated with behavior problems, the interaction of social capital and maternal depression was significantly related to behavior problems for adolescents. This interaction showed that living in neighborhoods with higher levels of social capital attenuated the relationship between maternal depression and adolescent behavior problems and confirmed the expectation that raising healthy well-adjusted children depends not only on the family, but also the context in which the family lives. PMID:24659390

The levels of stress, depression and anxiety of parents of disabled children in Turkey.

PubMed

Uskun, Ersin; Gundogar, Duru

2010-01-01

Parents of disabled children experience some special problems in their lives. It is reported that the parents of disabled children experience a very high level of stress. This study aims to determine the situations in which the parents experience higher levels of stress; to investigate the relation between the levels of stress, depression and anxiety. This cross-sectional study was conducted with parents whose children attend a Special Education and Rehabilitation Centre. The total number of parents was 156 and 127 (81.4%) of them voluntarily participated in this study. A questionnaire form, consisting of questions regarding the socio-demographic characteristics of disabled children and of their parents, was given to the participants. Additionally, the participants were asked to score 10 possible stressful situations (financial problems, relations with other people, having limited free time, not to be able to participate in social activities, etc.) on a scale of 0-10 points. Moreover, psychometric scales such as Beck Depression Inventory (BDI) and Spielberger State Trait Anxiety Inventory (STAI) were applied to the participants. The mean BDI (SD) score was found to be 14.9 (10.9). The mean STAI-state and STAI-trait scores were 55.1 ± 12.2 and 48.6 ± 8.8, respectively. Among the stressful experiences, the parents gave the highest points to 'attitudes of society towards disabled people', 'having limited free time' and 'financial problems' (Top three situations). In multiple analyses, it was found that by employing the BDI there was a relation between financial problems (ß: 0.32, p < 0.01), a decrease in relations with other people (ß: 0.21, p < 0.05), having limited free time (ß: -0.19, p < 0.05) and insufficiency of physical structures (ß: 0.21, p < 0.05). The relations between financial problems (ß: 0.31, p < 0.01) and being an individual who has close relations with disabled person other than his/her parents (ß: 0.27, p < 0.01) were defined employing the STAI-state as effective variables. 'Negative attitudes of society towards disabled people' (ß: 0.29; p < 0.01) were defined employing the STAI-trait as the only effective variable. Financial problems are the most important factors that affect the psychology of the parents of disabled people. Social programmes that support the parents in respect of both financial matters and home-care facilities should be set up.

The 3D elliptic restricted three-body problem: periodic orbits which bifurcate from limiting restricted problems. Complex instability

NASA Astrophysics Data System (ADS)

Ollé, Mercè; Pacha, Joan R.

1999-11-01

In the present work we use certain isolated symmetric periodic orbits found in some limiting Restricted Three-Body Problems to obtain, by numerical continuation, families of symmetric periodic orbits of the more general Spatial Elliptic Restricted Three Body Problem. In particular, the Planar Isosceles Restricted Three Body Problem, the Sitnikov Problem and the MacMillan problem are considered. A stability study for the periodic orbits of the families obtained - specially focused to detect transitions to complex instability - is also made.

Generalized Bondi-Sachs equations for characteristic formalism of numerical relativity

NASA Astrophysics Data System (ADS)

Cao, Zhoujian; He, Xiaokai

2013-11-01

The Cauchy formalism of numerical relativity has been successfully applied to simulate various dynamical spacetimes without any symmetry assumption. But discovering how to set a mathematically consistent and physically realistic boundary condition is still an open problem for Cauchy formalism. In addition, the numerical truncation error and finite region ambiguity affect the accuracy of gravitational wave form calculation. As to the finite region ambiguity issue, the characteristic extraction method helps much. But it does not solve all of the above issues. Besides the above problems for Cauchy formalism, the computational efficiency is another problem. Although characteristic formalism of numerical relativity suffers the difficulty from caustics in the inner near zone, it has advantages in relation to all of the issues listed above. Cauchy-characteristic matching (CCM) is a possible way to take advantage of characteristic formalism regarding these issues and treat the inner caustics at the same time. CCM has difficulty treating the gauge difference between the Cauchy part and the characteristic part. We propose generalized Bondi-Sachs equations for characteristic formalism for the Cauchy-characteristic matching end. Our proposal gives out a possible same numerical evolution scheme for both the Cauchy part and the characteristic part. And our generalized Bondi-Sachs equations have one adjustable gauge freedom which can be used to relate the gauge used in the Cauchy part. Then these equations can make the Cauchy part and the characteristic part share a consistent gauge condition. So our proposal gives a possible new starting point for Cauchy-characteristic matching.

Preliminary Effectiveness Study of Coping Power Program for Aggressive Children in Pakistan.

PubMed

Mushtaq, Asia; Lochman, John E; Tariq, Pervaiz N; Sabih, Fazaila

2017-10-01

Aggression is a characteristic feature of many psychiatric disorders. To address the scarceness for evidence-based interventions for behavioral problems in Pakistan, we evaluated the effectiveness of culturally adapted version of Coping Power Program. The purpose of the study was to determine the extent to which Coping Power Program is capable of reducing aggressive behavior and improving competent behavior, when delivered in a different culture, i.e., Pakistan. With randomized control trial (RCT) of pre- and post-testing, 112 fourth grade boys were allocated to Coping Power intervention condition and waitlist control condition. The intervention group showed significant reduction in aggression at post assessment, in comparison to control group. Boys who received Coping Power intervention also showed improvements in behavior, social skills, and social cognitive processes, with better anger control and problem solving strategies, in comparison to the control group. The results of the study provide preliminary evidence, supporting the effectiveness of Coping Power Program for Pakistani children. Despite its limitations, the results of this study are promising and suggest that Coping Power is an effective intervention to reduce behavioral problems and promote healthy and positive behaviors in children, even when implemented in different contexts with greater potential for violence exposure.

Evaluating sedimentation problems in activated sludge treatment plants operating at complete sludge retention time.

PubMed

Amanatidou, Elisavet; Samiotis, Georgios; Trikoilidou, Eleni; Pekridis, George; Taousanidis, Nikolaos

2015-02-01

Zero net sludge growth can be achieved by complete retention of solids in activated sludge wastewater treatment, especially in high strength and biodegradable wastewaters. When increasing the solids retention time, MLSS and MLVSS concentrations reach a plateau phase and observed growth yields values tend to zero (Yobs ≈ 0). In this work, in order to evaluate sedimentation problems arised due to high MLSS concentrations and complete sludge retention operational conditions, two identical innovative slaughterhouse wastewater treatment plants were studied. Measurements of wastewaters' quality characteristics, treatment plant's operational conditions, sludge microscopic analysis and state point analysis were conducted. Results have shown that low COD/Nitrogen ratios increase sludge bulking and flotation phenomena due to accidental denitrification in clarifiers. High return activated sludge rate is essential in complete retention systems as it reduces sludge condensation and hydraulic retention time in the clarifiers. Under certain operational conditions sludge loading rates can greatly exceed literature limit values. The presented methodology is a useful tool for estimation of sedimentation problems encountered in activated sludge wastewater treatment plants with complete retention time. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comments on the Diffusive Behavior of Two Upwind Schemes

NASA Technical Reports Server (NTRS)

Wood, William A.; Kleb, William L.

1998-01-01

The diffusive characteristics of two upwind schemes, multi-dimensional fluctuation splitting and locally one-dimensional finite volume, are compared for scalar advection-diffusion problems. Algorithms for the two schemes are developed for node-based data representation on median-dual meshes associated with unstructured triangulations in two spatial dimensions. Four model equations are considered: linear advection, non-linear advection, diffusion, and advection-diffusion. Modular coding is employed to isolate the effects of the two approaches for upwind flux evaluation, allowing for head-to-head accuracy and efficiency comparisons. Both the stability of compressive limiters and the amount of artificial diffusion generated by the schemes is found to be grid-orientation dependent, with the fluctuation splitting scheme producing less artificial diffusion than the finite volume scheme. Convergence rates are compared for the combined advection-diffusion problem, with a speedup of 2.5 seen for fluctuation splitting versus finite volume when solved on the same mesh. However, accurate solutions to problems with small diffusion coefficients can be achieved on coarser meshes using fluctuation splitting rather than finite volume, so that when comparing convergence rates to reach a given accuracy, fluctuation splitting shows a speedup of 29 over finite volume.

Ultrasound guided electrical impedance tomography for 2D free-interface reconstruction

NASA Astrophysics Data System (ADS)

Liang, Guanghui; Ren, Shangjie; Dong, Feng

2017-07-01

The free-interface detection problem is normally seen in industrial or biological processes. Electrical impedance tomography (EIT) is a non-invasive technique with advantages of high-speed and low cost, and is a promising solution for free-interface detection problems. However, due to the ill-posed and nonlinear characteristics, the spatial resolution of EIT is low. To deal with the issue, an ultrasound guided EIT is proposed to directly reconstruct the geometric configuration of the target free-interface. In the method, the position of the central point of the target interface is measured by a pair of ultrasound transducers mounted at the opposite side of the objective domain, and then the position measurement is used as the prior information for guiding the EIT-based free-interface reconstruction. During the process, a constrained least squares framework is used to fuse the information from different measurement modalities, and the Lagrange multiplier-based Levenberg-Marquardt method is adopted to provide the iterative solution of the constraint optimization problem. The numerical results show that the proposed ultrasound guided EIT method for the free-interface reconstruction is more accurate than the single modality method, especially when the number of valid electrodes is limited.

Searching for the influence radius of AGN in nearby narrow emission-line galaxies using the CALIFA survey

NASA Astrophysics Data System (ADS)

Robleto-Orús, A. C.; Torres-Papaqui, J. P.; Coziol, R.; Morales-Vargas, A.; Romero-Cruz, F. J.; Ortega-Minakata, R. A.; Chow-Martinez, M.; Trejo-Alonso, J. J.

2017-07-01

In narrow emission-line galaxies, one important problem consists in discriminating gas ionization due to an AGN and gas ionization due to OB stars in active star-forming regions. This problem becomes more acute in case of AGNs classified as transition-type objects (TO), where star formation is relatively intense, and for LINERs, where the AGN is very weak. Thanks to the integral field spectroscopy, we have a new way to attack this problem. By definition, OB stars ionize a definite portion of space, the Strömgren's sphere, which size depends on the total luminosity of the star, its temperature, and the density of the surrounding gas. Therefore one expects gas ionized by OB stars to cover limited areas in a galaxy. On the other hand, due to the huge amount of ionizing photons emitted by an AGN, its "influence radius" is expected do be much more extended, in the order of kpc. Using a sample of galaxies from included in the CALIFA survey DR3, we will test a new way to measure the characteristic "influence radius" of AGN with different intensities.

Film stability in a vertical rotating tube with a core-gas flow.

NASA Technical Reports Server (NTRS)

Sarma, G. S. R.; Lu, P. C.; Ostrach, S.

1971-01-01

The linear hydrodynamic stability of a thin-liquid layer flowing along the inside wall of a vertical tube rotating about its axis in the presence of a core-gas flow is examined. The stability problem is formulated under the conditions that the liquid film is thin, the density and viscosity ratios of gas to liquid are small and the relative (axial) pressure gradient in the gas is of the same order as gravity. The resulting eigenvalue problem is first solved by a perturbation method appropriate to axisymmetric long-wave disturbances. The damped nature (to within the thin-film and other approximations made) of the nonaxisymmetric and short-wave disturbances is noted. In view of the limitations on a truncated perturbation solution when the disturbance wavenumber is not small, an initial value method using digital computer is presented. Stability characteristics of neutral, growing, and damped modes are presented showing the influences of rotation, surface tension, and the core-gas flow. Energy balance in a neutral mode is also illustrated.

Anesthesia for cesarean delivery in an achondroplastic dwarf: a case report.

PubMed

Huang, Jeffrey; Babins, Noah

2008-12-01

There are more than 100 different types of dwarfism. Achondroplasia is the most common form of this rare condition. The incidence of achondroplasia in the United States is about 15 per 1 million births. Although inherited as an autosomal dominant condition, 80% of cases result from spontaneous mutation. Underdevelopment and premature ossification of bones result in characteristic craniofacial and spinal abnormalities. Limited neck extension, foramen magnum stenosis, a large tongue, large mandible, and atlanto-axial instability can lead to increased difficulty of airway management. Severe kyphosis, scoliosis, spinal stenosis, and unpredictable spread of local anesthetics in the epidural space and subarachnoid space lead to reluctance to apply regional anesthesia in this patient group. In addition, pregnancy in a person with achondroplasis poses more problems for anesthetic selection. These problems include potential hypoxia, severely decreased functional residual capacity, risk of gastric aspiration, and supine hypotension. In this case report, we describe the anesthetic management of an achondroplastic dwarf who underwent cesarean delivery.

Overcoming time scale and finite size limitations to compute nucleation rates from small scale well tempered metadynamics simulations.

PubMed

Salvalaglio, Matteo; Tiwary, Pratyush; Maggioni, Giovanni Maria; Mazzotti, Marco; Parrinello, Michele

2016-12-07

Condensation of a liquid droplet from a supersaturated vapour phase is initiated by a prototypical nucleation event. As such it is challenging to compute its rate from atomistic molecular dynamics simulations. In fact at realistic supersaturation conditions condensation occurs on time scales that far exceed what can be reached with conventional molecular dynamics methods. Another known problem in this context is the distortion of the free energy profile associated to nucleation due to the small, finite size of typical simulation boxes. In this work the problem of time scale is addressed with a recently developed enhanced sampling method while contextually correcting for finite size effects. We demonstrate our approach by studying the condensation of argon, and showing that characteristic nucleation times of the order of magnitude of hours can be reliably calculated. Nucleation rates spanning a range of 10 orders of magnitude are computed at moderate supersaturation levels, thus bridging the gap between what standard molecular dynamics simulations can do and real physical systems.

Tools and approaches to ensure quality of vaccines throughout the cold chain.

PubMed

Kartoglu, Umit; Milstien, Julie

2014-07-01

The Expanded Program on Immunization was designed 40 years ago for two types of vaccines: those that are heat stable but freeze sensitive and those that are stable to freezing but heat labile. A cold chain was developed for transport and storage of such vaccines and established in all countries, despite limited access to resources and electricity in the poorest areas. However, cold chain problems occur in all countries. Recent changes to vaccines and vaccine handling include development and introduction of new vaccines with a wide range of characteristics, improvement of heat stability of several basic vaccines, observation of vaccine freezing as a real threat, development of regulatory pathways for both vaccine development and the supply chain, and emergence of new temperature monitoring devices that can pinpoint and avoid problems. With such tools, public health groups have now encouraged development of vaccines labeled for use in flexible cold chains and these tools should be considered for future systems.

Design of an image encryption scheme based on a multiple chaotic map

NASA Astrophysics Data System (ADS)

Tong, Xiao-Jun

2013-07-01

In order to solve the problem that chaos is degenerated in limited computer precision and Cat map is the small key space, this paper presents a chaotic map based on topological conjugacy and the chaotic characteristics are proved by Devaney definition. In order to produce a large key space, a Cat map named block Cat map is also designed for permutation process based on multiple-dimensional chaotic maps. The image encryption algorithm is based on permutation-substitution, and each key is controlled by different chaotic maps. The entropy analysis, differential analysis, weak-keys analysis, statistical analysis, cipher random analysis, and cipher sensibility analysis depending on key and plaintext are introduced to test the security of the new image encryption scheme. Through the comparison to the proposed scheme with AES, DES and Logistic encryption methods, we come to the conclusion that the image encryption method solves the problem of low precision of one dimensional chaotic function and has higher speed and higher security.

Drug-nutrient interactions in enteral feeding: a primary care focus.

PubMed

Varella, L; Jones, E; Meguid, M M

1997-06-01

Drug and nutrient interactions are complex and can take many forms, including malabsorption of either the drug or the nutrient component. Some drugs can stimulate or suppress appetite, whereas others can cause nausea and vomiting resulting in inadequate nutritional intake. Absorption of drugs is a complex process that can be affected by the physical characteristics of the gastrointestinal tract (GIT) as well. Depending on the physical properties of a drug, it may be absorbed in a limited area of the GIT or more diffusely along much of the entire length. Many diseases and conditions are also known to affect the GIT either directly or indirectly. Dietary factors also need to be considered when the "food" is an enteral formula. The widespread use of enteral tubes requires that consideration be given to patients receiving both enteral feedings and medication concurrently. The location of a tube in the gastrointestinal tract, as well as the problems involved in crushing and administering solid dosage forms, creates a unique set of problems.

Overcoming time scale and finite size limitations to compute nucleation rates from small scale well tempered metadynamics simulations

NASA Astrophysics Data System (ADS)

Salvalaglio, Matteo; Tiwary, Pratyush; Maggioni, Giovanni Maria; Mazzotti, Marco; Parrinello, Michele

2016-12-01

Condensation of a liquid droplet from a supersaturated vapour phase is initiated by a prototypical nucleation event. As such it is challenging to compute its rate from atomistic molecular dynamics simulations. In fact at realistic supersaturation conditions condensation occurs on time scales that far exceed what can be reached with conventional molecular dynamics methods. Another known problem in this context is the distortion of the free energy profile associated to nucleation due to the small, finite size of typical simulation boxes. In this work the problem of time scale is addressed with a recently developed enhanced sampling method while contextually correcting for finite size effects. We demonstrate our approach by studying the condensation of argon, and showing that characteristic nucleation times of the order of magnitude of hours can be reliably calculated. Nucleation rates spanning a range of 10 orders of magnitude are computed at moderate supersaturation levels, thus bridging the gap between what standard molecular dynamics simulations can do and real physical systems.

Design of a tokamak fusion reactor first wall armor against neutral beam impingement

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

Myers, R.A.

1977-12-01

The maximum temperatures and thermal stresses are calculated for various first wall design proposals, using both analytical solutions and the TRUMP and SAP IV Computer Codes. Beam parameters, such as pulse time, cycle time, and beam power, are varied. It is found that uncooled plates should be adequate for near-term devices, while cooled protection will be necessary for fusion power reactors. Graphite and tungsten are selected for analysis because of their desirable characteristics. Graphite allows for higher heat fluxes compared to tungsten for similar pulse times. Anticipated erosion (due to surface effects) and plasma impurity fraction are estimated. Neutron irradiationmore » damage is also discussed. Neutron irradiation damage (rather than erosion, fatigue, or creep) is estimated to be the lifetime-limiting factor on the lifetime of the component in fusion power reactors. It is found that the use of tungsten in fusion power reactors, when directly exposed to the plasma, will cause serious plasma impurity problems; graphite should not present such an impurity problem.« less

Multi-Tasking Non-Destructive Laser Technology in Conservation Diagnostic Procedures

NASA Astrophysics Data System (ADS)

Tornari, V.; Tsiranidou, E.; Orphanos, Y.; Falldorf, C.; Klattenhof, R.; Esposito, E.; Agnani, A.; Dabu, R.; Stratan, A.; Anastassopoulos, A.; Schipper, D.; Hasperhoven, J.; Stefanaggi, M.; Bonnici, H.; Ursu, D.

Laser metrology provides techniques that have been successfully applied in industrial structural diagnostic fields but have not yet been refined and optimised for the special investigative requirements found in cultural heritage applications. A major impediment is the partial applicability of various optical coherent techniques, each one narrowing its use down to a specific application. This characteristic is not well suited for a field that encounters a great variety of diagnostic problems ranging from movable, multiple-composition museum objects, to immovable multi-layered wall paintings, statues and wood carvings, to monumental constructions and outdoor cultural heritage sites. Various diagnostic techniques have been suggested and are uniquely suited for each of the mentioned problems but it is this fragmented suitability that obstructs the technology transfer. Since optical coherent techniques for metrology are based on fundamental principles and take advantage of similar procedures for generation of informative signals for data collection, then the imposed limits elevate our aim to identify complementary capabilities to accomplish the needed functionality.

Tools and approaches to ensure quality of vaccines throughout the cold chain

PubMed Central

Kartoglu, Umit; Milstien, Julie

2014-01-01

The Expanded Program on Immunization was designed 40 years ago for two types of vaccines: those that are heat stable but freeze sensitive and those that are stable to freezing but heat labile. A cold chain was developed for transport and storage of such vaccines and established in all countries, despite limited access to resources and electricity in the poorest areas. However, cold chain problems occur in all countries. Recent changes to vaccines and vaccine handling include development and introduction of new vaccines with a wide range of characteristics, improvement of heat stability of several basic vaccines, observation of vaccine freezing as a real threat, development of regulatory pathways for both vaccine development and the supply chain, and emergence of new temperature monitoring devices that can pinpoint and avoid problems. With such tools, public health groups have now encouraged development of vaccines labeled for use in flexible cold chains and these tools should be considered for future systems. PMID:24865112

COP improvement of refrigerator/freezers, air-conditioners, and heat pumps using nonazeotropic refrigerant mixtures

NASA Technical Reports Server (NTRS)

Westra, Douglas G.

1993-01-01

With the February, 1992 announcement by President Bush to move the deadline for outlawing CFC (chloro-fluoro-carbon) refrigerants from the year 2000 to the year 1996, the refrigeration and air-conditioning industries have been accelerating their efforts to find alternative refrigerants. Many of the alternative refrigerants being evaluated require synthetic lubricants, are less efficient, and have toxicity problems. One option to developing new, alternative refrigerants is to combine existing non-CFC refrigerants to form a nonazeotropic mixture, with the concentration optimized for the given application so that system COP (Coefficient Of Performance) may be maintained or even improved. This paper will discuss the dilemma that industry is facing regarding CFC phase-out and the problems associated with CFC alternatives presently under development. A definition of nonazeotropic mixtures will be provided, and the characteristics and COP benefits of nonazeotropic refrigerant mixtures will be explained using thermodynamic principles. Limitations and disadvantages of nonazeotropic mixtures will be discussed, and example systems using such mixtures will be reviewed.

Prevalence and risk of violence and the physical, mental, and sexual health problems associated with human trafficking: systematic review.

PubMed

Oram, Siân; Stöckl, Heidi; Busza, Joanna; Howard, Louise M; Zimmerman, Cathy

2012-01-01

There is very limited evidence on the health consequences of human trafficking. This systematic review reports on studies investigating the prevalence and risk of violence while trafficked and the prevalence and risk of physical, mental, and sexual health problems, including HIV, among trafficked people. We conducted a systematic review comprising a search of Medline, PubMed, PsycINFO, EMBASE, and Web of Science, hand searches of reference lists of included articles, citation tracking, and expert recommendations. We included peer-reviewed papers reporting on the prevalence or risk of violence while trafficked and/or on the prevalence or risk of any measure of physical, mental, or sexual health among trafficked people. Two reviewers independently screened papers for eligibility and appraised the quality of included studies. The search identified 19 eligible studies, all of which reported on trafficked women and girls only and focused primarily on trafficking for sexual exploitation. The review suggests a high prevalence of violence and of mental distress among women and girls trafficked for sexual exploitation. The random effects pooled prevalence of diagnosed HIV was 31.9% (95% CI 21.3%-42.4%) in studies of women accessing post-trafficking support in India and Nepal, but the estimate was associated with high heterogeneity (I² = 83.7%). Infection prevalence may be related as much to prevalence rates in women's areas of origin or exploitation as to the characteristics of their experience. Findings are limited by the methodological weaknesses of primary studies and their poor comparability and generalisability. Although limited, existing evidence suggests that trafficking for sexual exploitation is associated with violence and a range of serious health problems. Further research is needed on the health of trafficked men, individuals trafficked for other forms of exploitation, and effective health intervention approaches.

Prevalence and Risk of Violence and the Physical, Mental, and Sexual Health Problems Associated with Human Trafficking: Systematic Review

PubMed Central

Oram, Siân; Stöckl, Heidi; Busza, Joanna; Howard, Louise M.; Zimmerman, Cathy

2012-01-01

Background There is very limited evidence on the health consequences of human trafficking. This systematic review reports on studies investigating the prevalence and risk of violence while trafficked and the prevalence and risk of physical, mental, and sexual health problems, including HIV, among trafficked people. Methods and Findings We conducted a systematic review comprising a search of Medline, PubMed, PsycINFO, EMBASE, and Web of Science, hand searches of reference lists of included articles, citation tracking, and expert recommendations. We included peer-reviewed papers reporting on the prevalence or risk of violence while trafficked and/or on the prevalence or risk of any measure of physical, mental, or sexual health among trafficked people. Two reviewers independently screened papers for eligibility and appraised the quality of included studies. The search identified 19 eligible studies, all of which reported on trafficked women and girls only and focused primarily on trafficking for sexual exploitation. The review suggests a high prevalence of violence and of mental distress among women and girls trafficked for sexual exploitation. The random effects pooled prevalence of diagnosed HIV was 31.9% (95% CI 21.3%–42.4%) in studies of women accessing post-trafficking support in India and Nepal, but the estimate was associated with high heterogeneity (I 2 = 83.7%). Infection prevalence may be related as much to prevalence rates in women's areas of origin or exploitation as to the characteristics of their experience. Findings are limited by the methodological weaknesses of primary studies and their poor comparability and generalisability. Conclusions Although limited, existing evidence suggests that trafficking for sexual exploitation is associated with violence and a range of serious health problems. Further research is needed on the health of trafficked men, individuals trafficked for other forms of exploitation, and effective health intervention approaches. Please see later in the article for the Editors' Summary PMID:22666182

Biopsychosocial Predictors of Fall Events among Older African Americans

PubMed Central

Nicklett, Emily Joy; Taylor, Robert Joseph; Rostant, Ola; Johnson, Kimson E.; Evans, Linnea

2016-01-01

This study identifies risk and protective factors for falls among older, community-dwelling African Americans. Drawing upon the biopsychosocial perspective (Engel, 1997), we conducted a series of sex- and age-adjusted multinomial logistic regression analyses to identify the correlates of fall events among older African Americans. Our sample consisted of 1,442 community-dwelling African Americans aged 65 and older, participating in the 2010-12 rounds of the Health and Retirement Study. Biophysical characteristics associated with greater relative risk of experiencing single and/or multiple falls included greater functional limitations, poorer self-rated health, poorer self-rated vision, chronic illnesses (high blood pressure, diabetes, cancer, lung disease, heart problems, stroke, and arthritis), greater chronic illness comorbidity, older age, and female sex. Physical activity was negatively associated with recurrent falls. Among the examined psychosocial characteristics, greater depressive symptoms were associated with greater relative risk of experiencing single and multiple fall events. Implications for clinicians and future studies are discussed. PMID:28285579

Measurements in Flight of the Longitudinal-Stability Characteristics of a Republic YF-84A Airplane (Army Serial No. 45-59488) at High Subsonic Mach Numbers

NASA Technical Reports Server (NTRS)

Turner, Howard L.; Cooper, George E.

1948-01-01

A brief investigation was made of the longitudinal-stability characteristics of a YF-84A airplane (Army Serial No. 45-79488). The airplane developed a pitching-up tendency at approximately 0.80 Mach number which necessitated large push forces and down-elevator deflections for further increases in speed. In steady turns at 35,000 feet with the center of gravity at 28.3 percent mean aerodynamic chord for normal accelerations up to the maximum test value, the control-force gradients were excessive at Mach numbers over 0.78. Airplane buffeting did not present a serious problem in accelerated or unaccelerated flight at 15,000 and 35,000 feet up to the maximum test Mach number of 0.84. It is believed that excessive control force would be the limiting factor in attaining speeds in excess of 0.84 Mach number, especially at altitudes below 35,000 feet.

Pose estimation of industrial objects towards robot operation

NASA Astrophysics Data System (ADS)

Niu, Jie; Zhou, Fuqiang; Tan, Haishu; Cao, Yu

2017-10-01

With the advantages of wide range, non-contact and high flexibility, the visual estimation technology of target pose has been widely applied in modern industry, robot guidance and other engineering practices. However, due to the influence of complicated industrial environment, outside interference factors, lack of object characteristics, restrictions of camera and other limitations, the visual estimation technology of target pose is still faced with many challenges. Focusing on the above problems, a pose estimation method of the industrial objects is developed based on 3D models of targets. By matching the extracted shape characteristics of objects with the priori 3D model database of targets, the method realizes the recognition of target. Thus a pose estimation of objects can be determined based on the monocular vision measuring model. The experimental results show that this method can be implemented to estimate the position of rigid objects based on poor images information, and provides guiding basis for the operation of the industrial robot.

Predictive factors for the Nursing Diagnoses in people living with Acquired Immune Deficiency Syndrome 1

PubMed Central

da Silva, Richardson Augusto Rosendo; Costa, Romanniny Hévillyn Silva; Nelson, Ana Raquel Cortês; Duarte, Fernando Hiago da Silva; Prado, Nanete Caroline da Costa; Rodrigues, Eduardo Henrique Fagundes

2016-01-01

Abstract Objective: to identify the predictive factors for the nursing diagnoses in people living with Acquired Immune Deficiency Syndrome. Method: a cross-sectional study, undertaken with 113 people living with AIDS. The data were collected using an interview script and physical examination. Logistic regression was used for the data analysis, considering a level of significance of 10%. Results: the predictive factors identified were: for the nursing diagnosis of knowledge deficit-inadequate following of instructions and verbalization of the problem; for the nursing diagnosis of failure to adhere - years of study, behavior indicative of failure to adhere, participation in the treatment and forgetfulness; for the nursing diagnosis of sexual dysfunction - family income, reduced frequency of sexual practice, perceived deficit in sexual desire, perceived limitations imposed by the disease and altered body function. Conclusion: the predictive factors for these nursing diagnoses involved sociodemographic and clinical characteristics, defining characteristics, and related factors, which must be taken into consideration during the assistance provided by the nurse. PMID:27384466

Compost feedstock characteristics and ratio modelling for organic waste materials co-composting in Malaysia.

PubMed

Chai, E W; H'ng, P S; Peng, S H; Wan-Azha, W M; Chin, K L; Chow, M J; Wong, W Z

2013-01-01

In Malaysia, large amounts of organic materials, which lead to disposal problems, are generated from agricultural residues especially from palm oil industries. Increasing landfill costs and regulations, which limit many types of waste accepted at landfills, have increased the interest in composting as a component of waste management. The objectives of this study were to characterize compost feedstock properties of common organic waste materials available in Malaysia. Thus, a ratio modelling of matching ingredients for empty fruit bunches (EFBs) co-composting using different organic materials in Malaysia was done. Organic waste materials with a C/N ratio of < 30 can be applied as a nitrogen source in EFB co-composting. The outcome of this study suggested that the percentage of EFB ranged between 50% and 60%, which is considered as the ideal mixing ratio in EFB co-composting. Conclusively, EFB can be utilized in composting if appropriate feedstock in term of physical and chemical characteristics is coordinated in the co-composting process.

Family characteristics of suicides in Cameron Highlands: a controlled study.

PubMed

Maniam, T

1994-09-01

Cameron Highlands has one of the highest suicide rates in the world, especially among Indians. Forty Indian families (19 suicides; 21 controls) were studied to compare family characteristics such as income, overcrowding, birth order of index cases of suicide, family history of suicidal behaviour or mental illness, marital disharmony, presence of alcohol abuse, availability of, and knowledge about, weedicides/insecticides, talk/threat of suicide among family members and experience of significant losses in the past year. Controls were matched for age, sex and educational level with the index cases of suicide. A significant difference was only found for one of the above factors, namely increased experience of significant losses in the past year in the family of index cases of suicide. More than 75% in both groups had alcohol related problems. About equal proportions in each group had a family history of suicidal behaviour and mental illness. There was more marital disharmony in families of suicides but this failed to reach significance. These results and methodological limitations of this study are discussed.

Solidarity outpatient clinics in Greece: a survey of a massive social movement.

PubMed

Evlampidou, Iro; Kogevinas, Manolis

2018-03-06

Until 2016, around 3 million persons had limited access to health care in Greece due to the economic crisis. We describe a massive solidarity movement of community clinics and pharmacies in Greece. We conducted a survey in 2014-15 and describe the characteristics of community clinics and pharmacies spontaneously established all over Greece after 2008. A characteristic of the 92 active solidarity clinics is autonomous collective functioning, free services, and funding from non-governmental sources. The largest clinics examined more than 500 uninsured or partly insured patients per month. Clinics covered a wide range of clinical and preventive services. Funding, availability of drugs, vaccines, medical material and their legal status were the main problems identified. The solidarity movement involved thousands of health professionals covering essential population needs. The community outpatient clinics were an outstanding example of solidarity and temporarily alleviated the health needs of a large part of the population. Copyright © 2018 SESPAS. Publicado por Elsevier España, S.L.U. All rights reserved.

Some aspects of the stability of the plane deformation mode of filaments of finite stiffness beyond the elasticity limits

NASA Astrophysics Data System (ADS)

Shimanovskii, A. V.

A method for calculating the plane bending of elastic-plastic filaments of finite stiffness is proposed on the basis of plastic flow theory. The problem considered is shown to reduce to relations similar to Kirchhoff equations for elastic work. Expressions are obtained for determining the normalized stiffness characteristics for the cross section of a filament with plastic regions containing beam theory equations as a particular case. A study is made of the effect of the plastic region size on the position of the elastic deformation-unloading interface and on the normalized stiffness of the filament cross section. Calculation results are presented in graphic form.

Discovering operating modes in telemetry data from the Shuttle Reaction Control System

NASA Technical Reports Server (NTRS)

Manganaris, Stefanos; Fisher, Doug; Kulkarni, Deepak

1994-01-01

This paper addresses the problem of detecting and diagnosing faults in physical systems, for which suitable system models are not available. An architecture is proposed that integrates the on-line acquisition and exploitation of monitoring and diagnostic knowledge. The focus is on the component of the architecture that discovers classes of behaviors with similar characteristics by observing a system in operation. A characterization of behaviors based on best fitting approximation models is investigated. An experimental prototype has been implemented to test it. Preliminary results in diagnosing faults of the reaction control system of the space shuttle are presented. The merits and limitations of the approach are identified and directions for future work are set.

Cardiac mesenchymal progenitors from postmortem cardiac tissues retained cellular characterization.

PubMed

Kami, D; Kitani, T; Nakata, M; Gojo, S

2014-05-01

Currently, cells for transplantation in regenerative medicine are derived from either autologous or allogeneic tissue. The former has the drawbacks that the quality of donor cells may depend on the condition of the patient, while the quantity of the cells may also be limited. To solve these problems, we investigated the potential of allogeneic cardiac mesenchymal progenitors (CMPs) derived from postmortem hearts, which may be immunologically privileged similar to bone marrow-derived mesenchymal progenitors. We examined whether viable CMPs could be isolated from C57/B6 murine cardiac tissues harvested at 24 hours postmortem. After 2- to 3-week propagation with a high dose of basic fibroblast growth factor, we performed cellular characteristics analyses, which included proliferation and differentiation property flow cytometry and microarray analyses. Postmortem CMPs had a longer lag phase after seeding than CMPs obtained from living tissues, but otherwise had similar characteristics in all the analyses. In addition, global gene expression analysis by microarray showed that cells derived from postmortem and living tissues had similar characteristics. These results indicate that allogeneic postmortem CMPs have potential for cell transplantation because they circumvent the issue of both the quality and quantity of donor cells. Copyright © 2014 Elsevier Inc. All rights reserved.

A Multivariate Quality Loss Function Approach for Optimization of Spinning Processes

NASA Astrophysics Data System (ADS)

Chakraborty, Shankar; Mitra, Ankan

2018-05-01

Recent advancements in textile industry have given rise to several spinning techniques, such as ring spinning, rotor spinning etc., which can be used to produce a wide variety of textile apparels so as to fulfil the end requirements of the customers. To achieve the best out of these processes, they should be utilized at their optimal parametric settings. However, in presence of multiple yarn characteristics which are often conflicting in nature, it becomes a challenging task for the spinning industry personnel to identify the best parametric mix which would simultaneously optimize all the responses. Hence, in this paper, the applicability of a new systematic approach in the form of multivariate quality loss function technique is explored for optimizing multiple quality characteristics of yarns while identifying the ideal settings of two spinning processes. It is observed that this approach performs well against the other multi-objective optimization techniques, such as desirability function, distance function and mean squared error methods. With slight modifications in the upper and lower specification limits of the considered quality characteristics, and constraints of the non-linear optimization problem, it can be successfully applied to other processes in textile industry to determine their optimal parametric settings.

Designing capture trajectories to unstable periodic orbits around Europa

NASA Technical Reports Server (NTRS)

Russell, Ryan P.; Lam, Try

2006-01-01

The hostile environment of third body perturbations restricts a mission designer's ability to find well-behaved reproducible capture trajectories when dealing with limited control authority as is typical with low-thrust missions. The approach outlined in this paper confronts this shortcoming by utilizing dynamical systems theory and an extensive preexisting database of Restricted Three Body Problem (RTBP) periodic orbits. The stable manifolds of unstable periodic orbits are utilized to attract a spacecraft towards Europa. By selecting an appropriate periodic orbit, a mission designer can control important characteristics of the captured state including stability, minimum altitudes, characteristic inclinations, and characteristic radii among others. Several free parameters are optimized in the non-trivial mapping from the RTBP to a more realistic model. Although the ephemeris capture orbit is ballistic by design, low-thrust is used to target the state that leads to the capture orbit, control the spacecraft after arriving on the unstable quasi-periodic orbit, and begin the spiral down towards the science orbit. The approach allows a mission designer to directly target fuel efficient captures at Europa in an ephemeris model. Furthermore, it provides structure and controllability to the design of capture trajectories that reside in a chaotic environment.

Characteristics of Pre-Service Primary School Teachers' Configural Reasoning

ERIC Educational Resources Information Center

Llinares, Salvador; Clemente, Francisco

2014-01-01

The goal of this study is to identify the characteristics of pre-service primary teachers' configural reasoning, understood as the relationships between concepts and figures set to solve geometrical proof problems. Ninety-seven primary teachers were asked to solve two geometrical proof problems in which a geometrical figure was provided. The…

Problem Gambling in Chinese American Adolescents: Characteristics and Risk Factors

ERIC Educational Resources Information Center

Chiu, Eddie Yu-Wai; Woo, Kent

2012-01-01

This preliminary study examined the characteristics and risk factors of problem gambling among Chinese American adolescents. A total of 192 Chinese American students (aged 13-19) from 9th to 12th grades were recruited from three high schools in San Francisco, California. Students were administered the South Oaks Gambling Screen Revised for…

The Family Environment and Developmental Psychopathology: The Unique and Interactive Effects of Depression, Attention, and Conduct Problems

ERIC Educational Resources Information Center

George, Carrie; Herman, Keith C.; Ostrander, Rick

2006-01-01

Prior studies have found remarkable similarity in the family characteristics across a wide range of child psychopathologies. This study investigated the unique relationships between symptoms of depression, conduct problems/aggression, and inattention/hyperactivity and characteristics of the family environment. Parents and teachers completed…

A Project to Enhance Superintendents' Knowledge and Application of Characteristics of High Quality Teachers

ERIC Educational Resources Information Center

Pummill, Bret L.; Edson, Jerry C.; Loftin, Michelle M.; Robinson, Matthew A.

2011-01-01

This report describes a problem based learning project focusing on superintendents' knowledge of the characteristics of high quality teachers. Current research findings offer evidence teacher quality is an important school variable related to student achievement. School district leaders are faced with the problem of identifying the characteristics…

Assessing the Quality of Problems in Problem-Based Learning

ERIC Educational Resources Information Center

Sockalingam, Nachamma; Rotgans, Jerome; Schmidt, Henk

2012-01-01

This study evaluated the construct validity and reliability of a newly devised 32-item problem quality rating scale intended to measure the quality of problems in problem-based learning. The rating scale measured the following five characteristics of problems: the extent to which the problem (1) leads to learning objectives, (2) is familiar, (3)…

Multistatic aerosol-cloud lidar in space: A theoretical perspective

NASA Astrophysics Data System (ADS)

Mishchenko, M. I.; Alexandrov, M. D.; Brian, C.; Travis, L. D.

2016-12-01

Accurate aerosol and cloud retrievals from space remain quite challenging and typically involve solving a severely ill-posed inverse scattering problem. In this Perspective, we formulate in general terms an aerosol and aerosol-cloud interaction space mission concept intended to provide detailed horizontal and vertical profiles of aerosol physical characteristics as well as identify mutually induced changes in the properties of aerosols and clouds. We argue that a natural and feasible way of addressing the ill-posedness of the inverse scattering problem while having an exquisite vertical-profiling capability is to fly a multistatic (including bistatic) lidar system. We analyze theoretically the capabilities of a formation-flying constellation of a primary satellite equipped with a conventional monostatic (backscattering) lidar and one or more additional platforms each hosting a receiver of the scattered laser light. If successfully implemented, this concept would combine the measurement capabilities of a passive multi-angle multi-spectral polarimeter with the vertical profiling capability of a lidar; address the ill-posedness of the inverse problem caused by the highly limited information content of monostatic lidar measurements; address the ill-posedness of the inverse problem caused by vertical integration and surface reflection in passive photopolarimetric measurements; relax polarization accuracy requirements; eliminate the need for exquisite radiative-transfer modeling of the atmosphere-surface system in data analyses; yield the day-and-night observation capability; provide direct characterization of ground-level aerosols as atmospheric pollutants; and yield direct measurements of polarized bidirectional surface reflectance. We demonstrate, in particular, that supplementing the conventional backscattering lidar with just one additional receiver flown in formation at a scattering angle close to 170° can dramatically increase the information content of the measurements. Although the specific subject of this Perspective is the multistatic lidar concept, all our conclusions equally apply to a multistatic radar system intended to study from space the global distribution of cloud and precipitation characteristics.

Multistatic Aerosol Cloud Lidar in Space: A Theoretical Perspective

NASA Technical Reports Server (NTRS)

Mishchenko, Michael I.; Alexandrov, Mikhail D.; Cairns, Brian; Travis, Larry D.

2016-01-01

Accurate aerosol and cloud retrievals from space remain quite challenging and typically involve solving a severely ill-posed inverse scattering problem. In this Perspective, we formulate in general terms an aerosol and aerosol-cloud interaction space mission concept intended to provide detailed horizontal and vertical profiles of aerosol physical characteristics as well as identify mutually induced changes in the properties of aerosols and clouds. We argue that a natural and feasible way of addressing the ill-posedness of the inverse scattering problem while having an exquisite vertical-profiling capability is to fly a multistatic (including bistatic) lidar system. We analyze theoretically the capabilities of a formation-flying constellation of a primary satellite equipped with a conventional monostatic (backscattering) lidar and one or more additional platforms each hosting a receiver of the scattered laser light. If successfully implemented, this concept would combine the measurement capabilities of a passive multi-angle multi-spectral polarimeter with the vertical profiling capability of a lidar; address the ill-posedness of the inverse problem caused by the highly limited information content of monostatic lidar measurements; address the ill-posedness of the inverse problem caused by vertical integration and surface reflection in passive photopolarimetric measurements; relax polarization accuracy requirements; eliminate the need for exquisite radiative-transfer modeling of the atmosphere-surface system in data analyses; yield the day-and-night observation capability; provide direct characterization of ground-level aerosols as atmospheric pollutants; and yield direct measurements of polarized bidirectional surface reflectance. We demonstrate, in particular, that supplementing the conventional backscattering lidar with just one additional receiver flown in formation at a scattering angle close to 170deg can dramatically increase the information content of the measurements. Although the specific subject of this Perspective is the multistatic lidar concept, all our conclusions equally apply to a multistatic radar system intended to study from space the global distribution of cloud and precipitation characteristics.

Psychosocial functioning in Dutch foster children: The relationship with child, family, and placement characteristics.

PubMed

Goemans, Anouk; van Geel, Mitch; Vedder, Paul

2016-06-01

Foster care is the preferred alternative for out-of-home care, but not necessarily beneficial for foster children's psychosocial functioning. This dilemma leaves researchers with a challenge to find out more about the factors related to foster children's social and emotional functioning. In a sample of 446 Dutch foster children we examined the extent to which three clusters of characteristics, those akin to the foster child, the foster family, or foster placement, were related to foster children's functioning at the time of research. Multivariate three-step hierarchical regression analyses were performed for three outcome variables: externalizing problems, internalizing problems, and prosocial behavior. We found that all three clusters of foster care characteristics were significantly related to foster children's functioning. Foster placement characteristics, in particular interventions aimed at foster children, explained the largest amount of variance in behavior problems. Children receiving interventions had more externalizing and internalizing problems. A possible explanation is that interventions are indicated for those foster children who are in the highest need of additional support. Prosocial behavior was particularly related to foster family characteristics. The results were mostly in line with international research. Careful screening and monitoring of the social and emotional functioning of foster children may help to identify problems at an early stage. In addition (preventive) support should be offered to those foster children and families who are in need of it. Copyright © 2016 Elsevier Ltd. All rights reserved.

Acoustic field of a pulsating cylinder in a rarefied gas: Thermoviscous and curvature effects

NASA Astrophysics Data System (ADS)

Ben Ami, Y.; Manela, A.

2017-09-01

We study the acoustic field of a circular cylinder immersed in a rarefied gas and subject to harmonic small-amplitude normal-to-wall displacement and heat-flux excitations. The problem is analyzed in the entire range of gas rarefaction rates and excitation frequencies, considering both single cylinder and coaxial cylinders setups. Numerical calculations are carried out via the direct simulation Monte Carlo method, applying a noniterative algorithm to impose the boundary heat-flux condition. Analytical predictions are obtained in the limits of ballistic- and continuum-flow conditions. Comparing with a reference inviscid continuum solution, the results illustrate the specific impacts of gas rarefaction and boundary curvature on the acoustic source efficiency. Inspecting the far-field properties of the generated disturbance, the continuum-limit solution exhibits an exponential decay of the signal with the distance from the source, reflecting thermoviscous effects, and accompanied by an inverse square-root decay, characteristic of the inviscid problem. Stronger attenuation is observed in the ballistic limit, where boundary curvature results in "geometric reduction" of the molecular layer affected by the source, and the signal vanishes at a distance of few acoustic wavelengths from the cylinder. The combined effects of mechanical and thermal excitations are studied to seek for optimal conditions to monitor the vibroacoustic signal. The impact of boundary curvature becomes significant in the ballistic-flow regime, where the optimal heat-flux amplitude required for sound reduction decreases with the distance from the source and is essentially a function of the acoustic-wavelength-scaled distance only.

Method of Reproduction of the Luminous Flux of the LED Light Sources by a Spherical Photometer

NASA Astrophysics Data System (ADS)

Huriev, M.; Neyezhmakov, P.

2018-02-01

In connection with transition to energy-efficient temporally stable light-emitting diodes (LEDs) lighting, a problem of ensuring the traceability of results of measurement of characteristics of light sources arises. The problem is related to existing measurement standards of luminous flux based on spherical photometers optimized for the reference incandescent lamps with a relative spectral characteristic different from the spectrum of the LEDs. We propose a method for reproduction of the luminous flux, which solves this problem.

Differences in characteristics of Asian American and white problem gamblers calling a gambling helpline.

PubMed

Barry, Declan T; Steinberg, Marvin A; Wu, Ran; Potenza, Marc N

2009-02-01

The characteristics of Asian American and white problem gamblers using a gambling helpline were examined to identify race-related differences. Logistic regression analyses were conducted on data obtained from callers to a gambling helpline serving southern New England in 2000-2003, inclusive. Of the 144 phone calls used in the analyses, 72 were from Asian American callers and 72 were from white callers who were matched on gender, education, income, marital/cohabitation status, and age. Race-related differences were observed in forms of gambling problems, psychiatric problems secondary to gambling, substance use problems, and family history. Asian American gamblers were more likely to report suicide attempts related to gambling and problems with non-strategic gambling. White gamblers were more likely to report both casino and non-casino gambling problems and personal and familial alcohol use problems. High proportions of both groups reported problems with strategic gambling, gambling-related anxiety, family and financial problems secondary to gambling, financial debt, daily tobacco use, and a family history of problem gambling. Race-related differences should be considered in optimizing prevention and treatment strategies related to problem gambling.

A Study on a Centralized Under-Voltage Load Shedding Scheme Considering the Load Characteristics

NASA Astrophysics Data System (ADS)

Deng, Jiyu; Liu, Junyong

Under-voltage load shedding is an important measure for maintaining voltage stability.Aiming at the optimal load shedding problem considering the load characteristics,firstly,the traditional under-voltage load shedding scheme based on a static load model may cause the analysis inaccurate is pointed out on the equivalent Thevenin circuit.Then,the dynamic voltage stability margin indicator is derived through local measurement.The derived indicator can reflect the voltage change of the key area in a myopia linear way.Dimensions of the optimal problem will be greatly simplified using this indicator.In the end,mathematical model of the centralized load shedding scheme is built with the indicator considering load characteristics.HSPPSO is introduced to slove the optimal problem.Simulation results on IEEE-39 system show that the proposed scheme display a good adaptability in solving the under-voltage load shedding considering dynamic load characteristics.

Joint surface modeling with thin-plate splines.

PubMed

Boyd, S K; Ronsky, J L; Lichti, D D; Salkauskas, K; Chapman, M A; Salkauskas, D

1999-10-01

Mathematical joint surface models based on experimentally determined data points can be used to investigate joint characteristics such as curvature, congruency, cartilage thickness, joint contact areas, as well as to provide geometric information well suited for finite element analysis. Commonly, surface modeling methods are based on B-splines, which involve tensor products. These methods have had success; however, they are limited due to the complex organizational aspect of working with surface patches, and modeling unordered, scattered experimental data points. An alternative method for mathematical joint surface modeling is presented based on the thin-plate spline (TPS). It has the advantage that it does not involve surface patches, and can model scattered data points without experimental data preparation. An analytical surface was developed and modeled with the TPS to quantify its interpolating and smoothing characteristics. Some limitations of the TPS include discontinuity of curvature at exactly the experimental surface data points, and numerical problems dealing with data sets in excess of 2000 points. However, suggestions for overcoming these limitations are presented. Testing the TPS with real experimental data, the patellofemoral joint of a cat was measured with multistation digital photogrammetry and modeled using the TPS to determine cartilage thicknesses and surface curvature. The cartilage thickness distribution ranged between 100 to 550 microns on the patella, and 100 to 300 microns on the femur. It was found that the TPS was an effective tool for modeling joint surfaces because no preparation of the experimental data points was necessary, and the resulting unique function representing the entire surface does not involve surface patches. A detailed algorithm is presented for implementation of the TPS.

Sensory characteristics and consumer acceptability of decaffeinated green teas.

PubMed

Lee, S M; Lee, H-S; Kim, K-H; Kim, K-O

2009-04-01

Green tea has been widely consumed for its mild flavors and its health benefits, yet caffeine in green tea has been a limitation for those who want to avoid it. The limitation brought increase in need for decaffeinated products in the green tea market. Most of the conventional decaffeination techniques applied in food use organic solvents. However, supercritical carbon dioxide fluid extraction (SC-CO2) method is gaining its intension as one of the future decaffeination methods that overcomes the problems of conventional methods. The purpose of this study was to identify sensory characteristics of decaffeinated green teas applied with SC-CO2 method and to observe the relationship with consumer acceptability to elucidate the potentiality of applying SC-CO2 technique in decaffeinated green tea market. Descriptive analysis was performed on 8 samples: green teas containing 4 caffeine levels (10%, 35%, 60%, and 100%) infused at 2 infusing periods (1 or 2 min). It was found that the SC-CO2 process not only reduced caffeine but also decreased some important features of original tea flavors. Two groups were recruited for consumer acceptability test: one (GP I, N = 52), consuming all types of green teas including hot/cold canned teas; and the other (GP II, N = 40), only consuming the loose type. While GP II liked original green tea the most, GP I liked highly decaffeinated green teas. Although the SC-CO2 method had limitations of losing complex flavors of green teas, it appeared to have future potential in the decaffeinated green tea market within or without the addition of desirable flavors.

Acceptance of Tinnitus As an Independent Correlate of Tinnitus Severity.

PubMed

Hesser, Hugo; Bånkestad, Ellinor; Andersson, Gerhard

2015-01-01

Tinnitus is the experience of sounds without an identified external source, and for some the experience is associated with significant severity (i.e., perceived negative affect, activity limitation, and participation restriction due to tinnitus). Acceptance of tinnitus has recently been proposed to play an important role in explaining heterogeneity in tinnitus severity. The purpose of the present study was to extend previous investigations of acceptance in relation to tinnitus by examining the unique contribution of acceptance in accounting for tinnitus severity, beyond anxiety and depression symptoms. In a cross-sectional study, 362 participants with tinnitus attending an ENT clinic in Sweden completed a standard set of psychometrically examined measures of acceptance of tinnitus, tinnitus severity, and anxiety and depression symptoms. Participants also completed a background form on which they provided information about the experience of tinnitus (loudness, localization, sound characteristics), other auditory-related problems (hearing problems and sound sensitivity), and personal characteristics. Correlational analyses showed that acceptance was strongly and inversely related to tinnitus severity and anxiety and depression symptoms. Multivariate regression analysis, in which relevant patient characteristics were controlled, revealed that acceptance accounted for unique variance beyond anxiety and depression symptoms. Acceptance accounted for more of the variance than anxiety and depression symptoms combined. In addition, mediation analysis revealed that acceptance of tinnitus mediated the direct association between self-rated loudness and tinnitus severity, even after anxiety and depression symptoms were taken into account. Findings add to the growing body of work, supporting the unique and important role of acceptance in tinnitus severity. The utility of the concept is discussed in relation to the development of new psychological models and interventions for tinnitus severity.

Use of Inappropriate and Inaccurate Conceptual Knowledge to Solve an Osmosis Problem.

ERIC Educational Resources Information Center

Zuckerman, June Trop

1995-01-01

Presents correct solutions to an osmosis problem of two high school science students who relied on inaccurate and inappropriate conceptual knowledge. Identifies characteristics of the problem solvers, salient properties of the problem that could contribute to the problem misrepresentation, and spurious correct answers. (27 references) (Author/MKR)

The Role of Psychosocial Characteristics in Criminal Convictions among Cocaine and Gambling Clients in Treatment

ERIC Educational Resources Information Center

Martin, Gina; Macdonald, Scott; Ishiguro, Sonya

2013-01-01

This study assessed the relative importance of problem gambling, cocaine use and selected psychosocial characteristics in predicting criminal convictions. A self-administered questionnaire was completed by clients when admitted to a treatment program for a primary problem with cocaine (n = 300), gambling (n = 199), or tobacco (n = 249). The…

Rotordynamic Instability Problems in High-Performance Turbomachinery

NASA Technical Reports Server (NTRS)

1984-01-01

Rotordynamics and predictions on the stability of characteristics of high performance turbomachinery were discussed. Resolutions of problems on experimental validation of the forces that influence rotordynamics were emphasized. The programs to predict or measure forces and force coefficients in high-performance turbomachinery are illustrated. Data to design new machines with enhanced stability characteristics or upgrading existing machines are presented.

Investigating Grade Nine Textbook Problems for Characteristics Related to Mathematical Literacy

ERIC Educational Resources Information Center

Gatabi, Abolfazl Rafiepour; Stacey, Kaye; Gooya, Zahra

2012-01-01

This study presents a content analysis of the new Iranian Grade 9 mathematics textbook and two Australian Year 9 mathematics textbooks, examining the extent to which the problems show characteristics associated in the literature with promoting mathematical literacy. The new Iranian book was produced to meet a range of needs including several well…

Characteristics of students in comparative problem solving

NASA Astrophysics Data System (ADS)

Irfan, M.; Sudirman; Rahardi, R.

2018-01-01

Often teachers provided examples and exercised to students with regard to comparative problems consisting of one quantity. In this study, the researchers gave the problem of comparison with the two quantities mixed. It was necessary to have a good understanding to solve this problem. This study aimed to determine whether students understand the comparison in depth and be able to solve the problem of non-routine comparison. This study used qualitative explorative methods, with researchers conducting in-depth interviews on subjects to explore the thinking process when solving comparative problems. The subject of this study was three students selected by purposive sampling of 120 students. From this research, researchers found there were three subjects with different characteristics, namely: subject 1, he did the first and second questions with methods of elimination and substitution (non-comparison); subject 2, he did the first question with the concept of comparison although the answer was wrong, and did the second question with the method of elimination and substitution (non-comparison); and subject 3, he did both questions with the concept of comparison. In the first question, he did wrong because he was unable to understand the problem, while on the second he did correctly. From the characteristics of the answers, the researchers divided into 3 groups based on thinking process, namely: blind-proportion, partial-proportion, and proportion thinking.

Aspects of emotional functioning following oesophageal cancer surgery in a population-based cohort study.

PubMed

Hellstadius, Ylva; Lagergren, Pernilla; Lagergren, Jesper; Johar, Asif; Hultman, Christina M; Wikman, Anna

2015-01-01

The aim of this study was to establish the proportion of patients reporting emotional problems following oesophagectomy for cancer and identify the risk characteristics for emotional problems. A Swedish population-based cohort study of patients with surgically treated oesophageal cancer was used. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30 was used to assess tension, worry, irritation and depressed mood at 6 months and 5 years after surgery. Potential risk characteristics were retrieved from medical notes and data linkages to Swedish health registries. Multivariable logistic regression analyses were performed to examine risk characteristics for poor emotional recovery. Of 401 patients included at 6 months, 49% reported problems with tension, 61% worry, 62% irritation and 63% depressed mood. Of the 140 (35%) patients who completed the 5-year follow-up, 39% reported problems with tension and about half of the patients reported problems with worry, irritation, and depressed mood (49, 45 and 52%, respectively). Squamous cell carcinoma was identified as a risk characteristic for tension (OR 2.15, 95% CI 1.30-3.55), worry (OR 2.02, 95% CI 1.19-3.40) and depressed mood (OR 1.71, 95% CI 1.01-2.90) at 6 months compared with adenocarcinoma. Compared with higher education, lower education was associated with tension (upper secondary schooling: OR 1.97, 95% CI 1.02-3.79 and 9-year compulsory: OR 2.46, 95% CI 1.28-4.74), while non-cohabitating patients were less likely to report problems with worry at 6 months (OR 0.53, 95% CI 0.34-0.84) compared with cohabitating patients. A substantial proportion of patients reports emotional problems following oesophagectomy, and risk characteristics include squamous cell carcinoma histology and low educational level. Copyright © 2014 John Wiley & Sons, Ltd.

Achievable Performance and Effective Interrogator Design for SAW RFID Sensor Tags

NASA Technical Reports Server (NTRS)

Barton Richard J.

2012-01-01

For many NASA missions, remote sensing is a critical application that supports activities such as environmental monitoring, planetary science, structural shape and health monitoring, non-destructive evaluation, etc. The utility of the remote sensing devices themselves is greatly increased if they are passive V that is, they do not require any on-board power supply such as batteries V and if they can be identified uniquely during the sensor interrogation process. Additional passive sensor characteristics that enable greater utilization in space applications are small size and weight, long read ranges with low interrogator power, ruggedness, and operability in extreme environments (vacuum, extreme high/low temperature, high radiation, etc.) In this paper, we consider one very promising passive sensor technology, called surface acoustic wave (SAW) radio-frequency identification (RFID), that satisfies all of these criteria. In general, RFID is a method of identifying items using radio waves to interrogate tags encoded with a unique identifier that are affixed to the items of interest. In the case of passive tags, only the interrogator, which transmits power to the tags in the form of radio-frequency electromagnetic radiation, requires access to a power supply. Passive RFID technologies are used today in many applications, including asset tracking and management, security and access control, and remote sensing. To date, most of the development and application in RFID technology has focused on either asset/inventory tracking and control or security and access control because these are the largest commercial application areas. Recently however, there has been growing interest in using passive RFID technology for remote sensing applications, and SAW devices are at the forefront of RFID sensing technology development. Although SAW RFID tags have great potential for use in numerous space-based remote sensing applications, the limited collision resolution capability of current generation tags limits the performance in a cluttered sensing environment. That is, as more SAW-based sensors are added to the environment, numerous tag responses are superimposed at the receiver and decoding all or even a subset of the telemetry becomes increasingly difficult. Background clutter generated by reflectors other than the sensors themselves is also a problem, as is multipath interference and signal distortion, but the limiting factor in many remote sensing applications can be expected to be tag mutual interference. This problem may be greatly mitigated by proper design of the SAW tag waveform, but that remains an open research problem, and in the meantime, several other related questions remain to be answered including: (1) What are the fundamental relationships between tag parameters such as bit-rate, time-bandwidth-product, SNR, and achievable collision resolution? (2) What are the differences in optimal or near-optimal interrogator designs between noise-limited environments and interference-limited environments? (3) What are the performance characteristics of different interrogator designs in term of parameters such as transmitter power level, range, and number of interfering tags? In this paper, we will present the results of a research effort aimed at providing at least partial answers to all of these questions.

Data Obtained in the Flight Measurements to Determine the Stability and Control Characteristics of a C-54D Airplane (AAF No. 42-72713) and a Summary of the Test Program

NASA Technical Reports Server (NTRS)

Talmage, Donald B.; Reeder, John P.

1947-01-01

The flight investigation of the C-54D airplane was initiated to determine the necessity of changes or additions to existing handling-qualities requirements to cove the case of instrument approaches with large airplanes. This paper gives a brief synopsis of the results and presents the measured data of tests to determine the stability and control characteristics. It was found that no new requirements were necessary to cover the problems of instrument approaches. The C-54D airplane tested met the Amy and Navy stability and control requirements except for the following items. The control-system friction with autopilot installed vas double that allowed by the requirements. The amount of friction was found to impair the controllability of the airplane in precision flying. The lateral and directional characteristics were good except that the maximum pb/2V was slightly below the minimum required, and the elevator-control forces to obtain the maximum pb/2V at low speeds were above the Army and Navy requirements. The longitudinal stability and control characteristics were good except that the elevator-control forces exceeded the limits of the Army and Navy requirements in turns and in landings. The stalling characteristics were considered good in all conditions with the stall warning in the form of tail buffeting occurring at speeds approximately 5 miles per hour above the stall.

Music algorithm for imaging of a sound-hard arc in limited-view inverse scattering problem

NASA Astrophysics Data System (ADS)

Park, Won-Kwang

2017-07-01

MUltiple SIgnal Classification (MUSIC) algorithm for a non-iterative imaging of sound-hard arc in limited-view inverse scattering problem is considered. In order to discover mathematical structure of MUSIC, we derive a relationship between MUSIC and an infinite series of Bessel functions of integer order. This structure enables us to examine some properties of MUSIC in limited-view problem. Numerical simulations are performed to support the identified structure of MUSIC.

Aerodynamics of an airfoil with a jet issuing from its surface

NASA Technical Reports Server (NTRS)

Tavella, D. A.; Karamcheti, K.

1982-01-01

A simple, two dimensional, incompressible and inviscid model for the problem posed by a two dimensional wing with a jet issuing from its lower surface is considered and a parametric analysis is carried out to observe how the aerodynamic characteristics depend on the different parameters. The mathematical problem constitutes a boundary value problem where the position of part of the boundary is not known a priori. A nonlinear optimization approach was used to solve the problem, and the analysis reveals interesting characteristics that may help to better understand the physics involved in more complex situations in connection with high lift systems.

Lame problem for a multilayer viscoelastic hollow ball with regard to inhomogeneous aging

NASA Astrophysics Data System (ADS)

Davtyan, Z. A.; Mirzoyan, S. Y.; Gasparyan, A. V.

2018-04-01

Determination of characteristics of the stress strain state of compound viscoelastic bodies is of both theoretical and practical interest. In the present paper, the Lamé problem is investigated for an uneven-aged multilayer viscoelastic hollow ball in the framework of N. Kh. Arutyunyan’s theory of creep of nonhomogeneously aging bodies [1, 2]. Solving this problem reduces to solving an inhomogeneous finite-difference equation of second order that contains operators with coordinates of time and space. The obtained formulas allow one to determine the required contact stresses and other mechanical characteristics of the problem related to uneven age of contacting balls.

Tackling the malaria problem in the South-East Asia Region: need for a change in policy?

PubMed

Bharati, Kaushik; Ganguly, N K

2013-01-01

Malaria is largely neglected in the South-East Asia Region (SEAR), although it has the highest number of people susceptible to the disease. Malaria in the SEAR exhibits special epidemiological characteristics such as "forest malaria" and malaria due to migration across international borders. The Greater Mekong Subregion (GMS) has been a focal-point for the emergence of drug resistant malaria. With the recent emergence of artemisinin resistance, coupled with the limited availability of insecticides, malaria control efforts in the SEAR face a steep challenge. Indirect man-made factors such as climate change, as well as direct man-made factors such as the circulation of counterfeit drugs have added to the problem. Increased monitoring, surveillance, pharmacovigilance as well as cross-border collaboration are required to address these problems. Regional networking and data-sharing will keep all stakeholders updated about the status of various malaria control programmes in the SEAR. Cutting-edge technologies such as GIS/GPS (geographical information system/global positioning system) systems and mobile phones can provide information in "real-time". A holistic and sustained approach to malaria control by integrated vector management (IVM) is suggested, in which all the stakeholder countries work collaboratively as a consortium. This approach will address the malaria problem in a collective manner so that malaria control can be sustained over time.

Tackling the malaria problem in the South-East Asia Region: Need for a change in policy?

PubMed Central

Bharati, Kaushik; Ganguly, N. K.

2013-01-01

Malaria is largely neglected in the South-East Asia Region (SEAR), although it has the highest number of people susceptible to the disease. Malaria in the SEAR exhibits special epidemiological characteristics such as “forest malaria” and malaria due to migration across international borders. The Greater Mekong Subregion (GMS) has been a focal-point for the emergence of drug resistant malaria. With the recent emergence of artemisinin resistance, coupled with the limited availability of insecticides, malaria control efforts in the SEAR face a steep challenge. Indirect man-made factors such as climate change, as well as direct man-made factors such as the circulation of counterfeit drugs have added to the problem. Increased monitoring, surveillance, pharmacovigilance as well as cross-border collaboration are required to address these problems. Regional networking and data-sharing will keep all stakeholders updated about the status of various malaria control programmes in the SEAR. Cutting-edge technologies such as GIS/GPS (geographical information system/global positioning system) systems and mobile phones can provide information in “real-time”. A holistic and sustained approach to malaria control by integrated vector management (IVM) is suggested, in which all the stakeholder countries work collaboratively as a consortium. This approach will address the malaria problem in a collective manner so that malaria control can be sustained over time. PMID:23481050

Stress state of rocks with a system of workings

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

Nikiforovskii, V.S.; Seryakov, V.M.

1979-09-01

An investigation of the state of rocks in undisturbed form, and during disturbance by drivage of development workings and the working of seams or ore beds, is both important and also extremely complex in practice. The complete physical and mathematical formulation of the problem must take into account the complex geological structure (allowing for tectonics) of the region, the mutual influence of the systems of workings, the change in the mechanical characteristics in the vicinity of the workings, etc. All these factors make it necessary to solve spatial problems with inclusions and workings of arbitrary form. The literature gives datamore » on the stress in the rock in the vicinity of a working remote from the free surface and in its vicinity. However, the possibilities of an analytical investigation of the problem are limited to the simplest cases under conditions of plane deformation. Considerable success in the solution of problems of geomechanics has been attained using numerical methods, particularly the finite-element method, which enables us, without altering the algorithm, to change fairly rapidly and simply the outer and inner boundaries of the region and the properties of the medium, or to assign various boundary conditions. In this article we calculate the stress in the rocks around mining-out and development workings during mining of the Talnakh and Oktyabr' deposits by the longwall slicing system with stowing of the worked-out area.« less

Presenteeism according to healthy behaviors, physical health, and work environment.

PubMed

Merrill, Ray M; Aldana, Steven G; Pope, James E; Anderson, David R; Coberley, Carter R; Whitmer, R William

2012-10-01

The objective of this study is to identify the contribution that selected demographic characteristics, health behaviors, physical health outcomes, and workplace environmental factors have on presenteeism (on-the-job productivity loss attributed to poor health and other personal issues). Analyses are based on a cross-sectional survey administered to 3 geographically diverse US companies in 2010. Work-related factors had the greatest influence on presenteeism (eg, too much to do but not enough time to do it, insufficient technological support/resources). Personal problems and financial stress/concerns also contributed substantially to presenteeism. Factors with less contribution to presenteeism included physical limitations, depression or anxiety, inadequate job training, and problems with supervisors and coworkers. Presenteeism was greatest for those ages 30-49, women, separated/divorced/widowed employees, and those with a high school degree or some college. Clerical/office workers and service workers had higher presenteeism. Managers and professionals had the highest level of presenteeism related to having too much to do but too little time to do it, and transportation workers had the greatest presenteeism because of physical health limitations. Lowering presenteeism will require that employers have realistic expectations of workers, help workers prioritize, and provide sufficient technological support. Financial stress and concerns may warrant financial planning services. Health promotion interventions aimed at improving nutrition and physical and mental health also may contribute to reducing presenteeism.

Sherlock Holmes, Master Problem Solver.

ERIC Educational Resources Information Center

Ballew, Hunter

1994-01-01

Shows the connections between Sherlock Holmes's investigative methods and mathematical problem solving, including observations, characteristics of the problem solver, importance of data, questioning the obvious, learning from experience, learning from errors, and indirect proof. (MKR)

A Study on Group Key Agreement in Sensor Network Environments Using Two-Dimensional Arrays

PubMed Central

Jang, Seung-Jae; Lee, Young-Gu; Lee, Kwang-Hyung; Kim, Tai-Hoon; Jun, Moon-Seog

2011-01-01

These days, with the emergence of the concept of ubiquitous computing, sensor networks that collect, analyze and process all the information through the sensors have become of huge interest. However, sensor network technology fundamentally has wireless communication infrastructure as its foundation and thus has security weakness and limitations such as low computing capacity, power supply limitations and price. In this paper, and considering the characteristics of the sensor network environment, we propose a group key agreement method using a keyset pre-distribution of two-dimension arrays that should minimize the exposure of key and personal information. The key collision problems are resolved by utilizing a polygonal shape’s center of gravity. The method shows that calculating a polygonal shape’s center of gravity only requires a very small amount of calculations from the users. The simple calculation not only increases the group key generation efficiency, but also enhances the sense of security by protecting information between nodes. PMID:22164072

Earth resources mission performance studies. Volume 2: Simulation results

NASA Technical Reports Server (NTRS)

1974-01-01

Simulations were made at three month intervals to investigate the EOS mission performance over the four seasons of the year. The basic objectives of the study were: (1) to evaluate the ability of an EOS type system to meet a representative set of specific collection requirements, and (2) to understand the capabilities and limitations of the EOS that influence the system's ability to satisfy certain collection objectives. Although the results were obtained from a consideration of a two sensor EOS system, the analysis can be applied to any remote sensing system having similar optical and operational characteristics. While the category related results are applicable only to the specified requirement configuration, the results relating to general capability and limitations of the sensors can be applied in extrapolating to other U.S. based EOS collection requirements. The TRW general purpose mission simulator and analytic techniques discussed in this report can be applied to a wide range of collection and planning problems of earth orbiting imaging systems.

Estimation of the limit of detection in semiconductor gas sensors through linearized calibration models.

PubMed

Burgués, Javier; Jiménez-Soto, Juan Manuel; Marco, Santiago

2018-07-12

The limit of detection (LOD) is a key figure of merit in chemical sensing. However, the estimation of this figure of merit is hindered by the non-linear calibration curve characteristic of semiconductor gas sensor technologies such as, metal oxide (MOX), gasFETs or thermoelectric sensors. Additionally, chemical sensors suffer from cross-sensitivities and temporal stability problems. The application of the International Union of Pure and Applied Chemistry (IUPAC) recommendations for univariate LOD estimation in non-linear semiconductor gas sensors is not straightforward due to the strong statistical requirements of the IUPAC methodology (linearity, homoscedasticity, normality). Here, we propose a methodological approach to LOD estimation through linearized calibration models. As an example, the methodology is applied to the detection of low concentrations of carbon monoxide using MOX gas sensors in a scenario where the main source of error is the presence of uncontrolled levels of humidity. Copyright © 2018 Elsevier B.V. All rights reserved.

[The psychovegetative disorders as an ego-structural problem].

PubMed

Ermann, M

1982-01-01

The personality structure of patients suffering from psychovegetative disorders is described in the present article from aspects of the psychology of the ego. The focus of all such disorders is a defective desomatization of affectations and the functions of perception. In proportion to the extent of the developmental disorder this specific pathology of the ego is either employed regressively in the defense of conflicts or serves for the release of a structurally strongly limited ego. More precise investigation of the ego structure leads to the descrimination between vegetative neuroses as limited ego pathology on the one hand and psychovegetative disorders in the context of a more extensive ego pathology, as they occur in borderline syndromes or serious narcissistic disorders of the personality on the other. Diagnostically the discrimination may be made by considering the patients own description of their complaints and the structure of their characters, by evaluating the quality of anxiety and affectations, and on the basis of the dynamics of the psychotherapeutic relationship. Consequently there are characteristic differences for the course of treatment.

Compact holographic optical neural network system for real-time pattern recognition

NASA Astrophysics Data System (ADS)

Lu, Taiwei; Mintzer, David T.; Kostrzewski, Andrew A.; Lin, Freddie S.

1996-08-01

One of the important characteristics of artificial neural networks is their capability for massive interconnection and parallel processing. Recently, specialized electronic neural network processors and VLSI neural chips have been introduced in the commercial market. The number of parallel channels they can handle is limited because of the limited parallel interconnections that can be implemented with 1D electronic wires. High-resolution pattern recognition problems can require a large number of neurons for parallel processing of an image. This paper describes a holographic optical neural network (HONN) that is based on high- resolution volume holographic materials and is capable of performing massive 3D parallel interconnection of tens of thousands of neurons. A HONN with more than 16,000 neurons packaged in an attache case has been developed. Rotation- shift-scale-invariant pattern recognition operations have been demonstrated with this system. System parameters such as the signal-to-noise ratio, dynamic range, and processing speed are discussed.

Nonlocal integral elasticity in nanostructures, mixtures, boundary effects and limit behaviours

NASA Astrophysics Data System (ADS)

Romano, Giovanni; Luciano, Raimondo; Barretta, Raffaele; Diaco, Marina

2018-02-01

Nonlocal elasticity is addressed in terms of integral convolutions for structural models of any dimension, that is bars, beams, plates, shells and 3D continua. A characteristic feature of the treatment is the recourse to the theory of generalised functions (distributions) to provide a unified presentation of previous proposals. Local-nonlocal mixtures are also included in the analysis. Boundary effects of convolutions on bounded domains are investigated, and analytical evaluations are provided in the general case. Methods for compensation of boundary effects are compared and discussed with a comprehensive treatment. Estimates of limit behaviours for extreme values of the nonlocal parameter are shown to give helpful information on model properties, allowing for new comments on previous proposals. Strain-driven and stress-driven models are shown to emerge by swapping the mechanical role of input and output fields in the constitutive convolution, with stress-driven elastic model leading to well-posed problems. Computations of stress-driven nonlocal one-dimensional elastic models are performed to exemplify the theoretical results.

Hyperspectral data analysis procedures with reduced sensitivity to noise

NASA Technical Reports Server (NTRS)

Landgrebe, David A.

1993-01-01

Multispectral sensor systems have become steadily improved over the years in their ability to deliver increased spectral detail. With the advent of hyperspectral sensors, including imaging spectrometers, this technology is in the process of taking a large leap forward, thus providing the possibility of enabling delivery of much more detailed information. However, this direction of development has drawn even more attention to the matter of noise and other deleterious effects in the data, because reducing the fundamental limitations of spectral detail on information collection raises the limitations presented by noise to even greater importance. Much current effort in remote sensing research is thus being devoted to adjusting the data to mitigate the effects of noise and other deleterious effects. A parallel approach to the problem is to look for analysis approaches and procedures which have reduced sensitivity to such effects. We discuss some of the fundamental principles which define analysis algorithm characteristics providing such reduced sensitivity. One such analysis procedure including an example analysis of a data set is described, illustrating this effect.

A SECOND-ORDER DIVERGENCE-CONSTRAINED MULTIDIMENSIONAL NUMERICAL SCHEME FOR RELATIVISTIC TWO-FLUID ELECTRODYNAMICS

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

Amano, Takanobu, E-mail: amano@eps.s.u-tokyo.ac.jp

A new multidimensional simulation code for relativistic two-fluid electrodynamics (RTFED) is described. The basic equations consist of the full set of Maxwell’s equations coupled with relativistic hydrodynamic equations for separate two charged fluids, representing the dynamics of either an electron–positron or an electron–proton plasma. It can be recognized as an extension of conventional relativistic magnetohydrodynamics (RMHD). Finite resistivity may be introduced as a friction between the two species, which reduces to resistive RMHD in the long wavelength limit without suffering from a singularity at infinite conductivity. A numerical scheme based on HLL (Harten–Lax–Van Leer) Riemann solver is proposed that exactlymore » preserves the two divergence constraints for Maxwell’s equations simultaneously. Several benchmark problems demonstrate that it is capable of describing RMHD shocks/discontinuities at long wavelength limit, as well as dispersive characteristics due to the two-fluid effect appearing at small scales. This shows that the RTFED model is a promising tool for high energy astrophysics application.« less

The prediction of nonlinear three dimensional combustion instability in liquid rockets with conventional nozzles

NASA Technical Reports Server (NTRS)

Powell, E. A.; Zinn, B. T.

1973-01-01

An analytical technique is developed to solve nonlinear three-dimensional, transverse and axial combustion instability problems associated with liquid-propellant rocket motors. The Method of Weighted Residuals is used to determine the nonlinear stability characteristics of a cylindrical combustor with uniform injection of propellants at one end and a conventional DeLaval nozzle at the other end. Crocco's pressure sensitive time-lag model is used to describe the unsteady combustion process. The developed model predicts the transient behavior and nonlinear wave shapes as well as limit-cycle amplitudes and frequencies typical of unstable motor operation. The limit-cycle amplitude increases with increasing sensitivity of the combustion process to pressure oscillations. For transverse instabilities, calculated pressure waveforms exhibit sharp peaks and shallow minima, and the frequency of oscillation is within a few percent of the pure acoustic mode frequency. For axial instabilities, the theory predicts a steep-fronted wave moving back and forth along the combustor.

Health literacy and communication quality in health care organizations.

PubMed

Wynia, Matthew K; Osborn, Chandra Y

2010-01-01

The relationship between limited health literacy and poor health may be due, in part, to poor communication quality within health care delivery organizations. We explored the relationship between health literacy status and receiving patient-centered communication in clinics and hospitals serving communication-vulnerable patient populations. Thirteen health care organizations nationwide distributed a survey to 5929 patients. All patients completed seven items assessing patient-centered communication. One third also completed three items assessing health literacy. The majority of patients had self-reported health literacy challenges, reporting problems learning about their medical condition because of difficulty understanding written information (53%), a lack of confidence in completing medical forms by themselves (61%), and needing someone to help them read hospital/clinic materials (57%). Logistic regression models showed that, after adjustment for patient demographic characteristics and health care organization type, patients with limited health literacy were 28% to 79% less likely than those with adequate health literacy to report their health care organization "always" provides patient-centered communication across seven communication items. Using a scaled composite of these items, limited health literacy remained associated with lower reported communication quality. These results suggest that improving communication quality in health care organizations might help to address the challenges facing patients with limited health literacy. They also highlight that efforts to address the needs of patients with limited health literacy should be sensitive to the range of communication challenges confronting these patients and their caregivers.

Characteristics of environmental pollution related with public complaints in an industrial shipbuilding complex, Korea.

PubMed

Chung, Jae-Woo; Lee, Myoung-Eun; Lee, Hyeon-Don

2011-06-01

The shipbuilding industry of Korea, ranked number one in the world in annual amount of ship orders, has contributed to national economic growth; however, this has resulted in various environmental problems. Characteristics of environmental pollution, such as particulate matters, odor, and noise, which are closely related with public complaints, were evaluated in an industrial shipbuilding complex. The concentrations of PM-10 and TSP were significantly affected by the distance between the measurement site and shipbuilding workplace, as well as the height of the measurement site. Average PM-10 concentrations in the residential area ranged from 40.10 to 44.10 μg/m(3), which were not high in comparison with the ambient air quality standard and those of major cities in Korea. Paint particles could affect a wider area than typical particulate matters due to their generation and transport properties. The properties of odor in the study area were widely affected by the work intensity in shipyards and the temperature. Twenty-five out of total 54 samples collected in the residential area exceeded the dilution factor of 10, which is the tolerable limit adopted in Korea. Noise had an influence on a limited area due to the extinction effect with distance from the shipyards, while severe noise levels higher than 90 dB(A) were frequently found inside the shipyards.

Modelling large scale human activity in San Francisco

NASA Astrophysics Data System (ADS)

Gonzalez, Marta

2010-03-01

Diverse group of people with a wide variety of schedules, activities and travel needs compose our cities nowadays. This represents a big challenge for modeling travel behaviors in urban environments; those models are of crucial interest for a wide variety of applications such as traffic forecasting, spreading of viruses, or measuring human exposure to air pollutants. The traditional means to obtain knowledge about travel behavior is limited to surveys on travel journeys. The obtained information is based in questionnaires that are usually costly to implement and with intrinsic limitations to cover large number of individuals and some problems of reliability. Using mobile phone data, we explore the basic characteristics of a model of human travel: The distribution of agents is proportional to the population density of a given region, and each agent has a characteristic trajectory size contain information on frequency of visits to different locations. Additionally we use a complementary data set given by smart subway fare cards offering us information about the exact time of each passenger getting in or getting out of the subway station and the coordinates of it. This allows us to uncover the temporal aspects of the mobility. Since we have the actual time and place of individual's origin and destination we can understand the temporal patterns in each visited location with further details. Integrating two described data set we provide a dynamical model of human travels that incorporates different aspects observed empirically.

Anomalous Temperature Dependence in Metal-Black Phosphorus Contact.

PubMed

Li, Xuefei; Grassi, Roberto; Li, Sichao; Li, Tiaoyang; Xiong, Xiong; Low, Tony; Wu, Yanqing

2018-01-10

Metal-semiconductor contact has been the performance limiting problem for electronic devices and also dictates the scaling potential for future generation devices based on novel channel materials. Two-dimensional semiconductors beyond graphene, particularly few layer black phosphorus, have attracted much attention due to their exceptional electronic properties such as anisotropy and high mobility. However, due to its ultrathin body nature, few layer black phosphorus-metal contact behaves differently than conventional Schottky barrier (SB) junctions, and the mechanisms of its carrier transport across such a barrier remain elusive. In this work, we examine the transport characteristic of metal-black phosphorus contact under varying temperature. We elucidated the origin of apparent negative SB heights extracted from classical thermionic emission model and also the phenomenon of metal-insulator transition observed in the current-temperature transistor characteristic. In essence, we found that the SB height can be modulated by the back-gate voltage, which beyond a certain critical point becomes so low that the injected carrier can no longer be described by the conventional thermionic emission theory. The transition from transport dominated by a Maxwell-Boltzmann distribution for the high energy tail states, to that of a Fermi distribution by low energy Fermi sea electrons, is the physical origin of the observed metal-insulator transition. We identified two distinctive tunneling limited transport regimes in the contact: vertical and longitudinal tunneling.

Stochastic generation of hourly rainstorm events in Johor

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

Nojumuddin, Nur Syereena; Yusof, Fadhilah; Yusop, Zulkifli

2015-02-03

Engineers and researchers in water-related studies are often faced with the problem of having insufficient and long rainfall record. Practical and effective methods must be developed to generate unavailable data from limited available data. Therefore, this paper presents a Monte-Carlo based stochastic hourly rainfall generation model to complement the unavailable data. The Monte Carlo simulation used in this study is based on the best fit of storm characteristics. Hence, by using the Maximum Likelihood Estimation (MLE) and Anderson Darling goodness-of-fit test, lognormal appeared to be the best rainfall distribution. Therefore, the Monte Carlo simulation based on lognormal distribution was usedmore » in the study. The proposed model was verified by comparing the statistical moments of rainstorm characteristics from the combination of the observed rainstorm events under 10 years and simulated rainstorm events under 30 years of rainfall records with those under the entire 40 years of observed rainfall data based on the hourly rainfall data at the station J1 in Johor over the period of 1972–2011. The absolute percentage error of the duration-depth, duration-inter-event time and depth-inter-event time will be used as the accuracy test. The results showed the first four product-moments of the observed rainstorm characteristics were close with the simulated rainstorm characteristics. The proposed model can be used as a basis to derive rainfall intensity-duration frequency in Johor.« less

Comparison of Decisions Quality of Heuristic Methods with Limited Depth-First Search Techniques in the Graph Shortest Path Problem

NASA Astrophysics Data System (ADS)

Vatutin, Eduard

2017-12-01

The article deals with the problem of analysis of effectiveness of the heuristic methods with limited depth-first search techniques of decision obtaining in the test problem of getting the shortest path in graph. The article briefly describes the group of methods based on the limit of branches number of the combinatorial search tree and limit of analyzed subtree depth used to solve the problem. The methodology of comparing experimental data for the estimation of the quality of solutions based on the performing of computational experiments with samples of graphs with pseudo-random structure and selected vertices and arcs number using the BOINC platform is considered. It also shows description of obtained experimental results which allow to identify the areas of the preferable usage of selected subset of heuristic methods depending on the size of the problem and power of constraints. It is shown that the considered pair of methods is ineffective in the selected problem and significantly inferior to the quality of solutions that are provided by ant colony optimization method and its modification with combinatorial returns.

Case Problems for Problem-Based Pedagogical Approaches: A Comparative Analysis

ERIC Educational Resources Information Center

Dabbagh, Nada; Dass, Susan

2013-01-01

A comparative analysis of 51 case problems used in five problem-based pedagogical models was conducted to examine whether there are differences in their characteristics and the implications of such differences on the selection and generation of ill-structured case problems. The five pedagogical models were: situated learning, goal-based scenario,…

Family employment and child socioemotional behaviour: longitudinal findings from the UK Millennium Cohort Study.

PubMed

Hope, Steven; Pearce, Anna; Whitehead, Margaret; Law, Catherine

2014-10-01

Levels of paid employment in two parent and lone parent families have increased in the UK but evidence of its impact on child socioemotional behaviour is limited and inconsistent. We conducted a longitudinal analysis using the first four sweeps of the Millennium Cohort Study (9 months, 3 years, 5 years and 7 years) to investigate the influence of family employment trajectories in the early years on socioemotional behaviour at 7 years, unadjusted and adjusted for covariates. In addition, mothers' employment was investigated separately. Children from families where no parent was employed for one or more sweeps were at a greater risk of socioemotional problem behaviour compared with those where a parent was continuously employed, even after adjustment for covariates. Children of mothers who were non-employed for one or more sweeps were at greater risk of problem behaviour compared with mothers who were employed at all sweeps. Adjustment for covariates fully attenuated the excess risk for children whose mothers had moved into employment by the time they were 7 years. In contrast, the elevated risk associated with continuous non-employment and a single transition out of employment was attenuated after adjustment for early covariates, fathers' employment, household income and mothers' psychological distress at 7 years, but remained significant. Family and mothers' employment were associated with a lower risk of problem behaviour for children in middle childhood, in part explained by sociodemographic characteristics of families and the apparent psychological and socioeconomic benefits of employment. Results for mothers' transitions in or out of the labour market suggest that child problem behaviour is influenced by current status, over and above diverse earlier experiences of employment and non-employment. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Pedagogical content knowledge: Knowledge of pedagogy novice teachers in mathematics learning on limit algebraic function

NASA Astrophysics Data System (ADS)

Ma'rufi, Budayasa, I. Ketut; Juniati, Dwi

2017-02-01

Teacher is one of the key aspects of student's achievement. Teachers should master content material taught, how to teach it, and can interpret the students' thinking so that students easily understand the subject matter. This research was a qualitative research that aimed at describing profile of PCK's teachers in mathematics on limit algebraic functions in terms of the differences of teaching experience. Pedagogical Content Knowledge (PCK) and understanding of teachers is defined as involving the relationship between knowledge of teaching materials, how to transfer the subject matter, and the knowledge of students in mathematics on limit algebraic functions that the subject matter may be understood by students. The PCK components in this research were knowledge of subject matter, knowledge of pedagogy, and knowledge of students. Knowledge of pedagogy defines as knowledge and understanding of teachers about the planning and organization of the learning and teaching strategy of limit algebraic function. The subjects were two mathematics high school teachers who teach in class XI IPS. Data were collected through observation of learning during five meetings and interviews before and after the lesson continued with qualitative data analysis. Focus of this article was to describe novice teacher's knowledge of student in mathematics learning on limit algebraic function. Based on the results of the analysis of qualitative data the data concluded that novice teacher's knowledge of pedagogy in mathematics on limit algebraic function showed: 1) in teaching the definitions tend to identify prior knowledge of the student experience with the material to be studied, but not in the form of a problem, 2) in posing the questions tend to be monotonous non lead and dig, 3) in response to student questions preservice teachers do not take advantage of the characteristics or the potential of other students, 4) in addressing the problem of students, tend to use the drill approach and did not give illustrations easily to understand by students, 5) in teaching application concepts, tend to explain procedurally, without explaining the reasons why these steps are carried out, 6) less varied in the use of learning strategies.

A genetic algorithm used for solving one optimization problem

NASA Astrophysics Data System (ADS)

Shipacheva, E. N.; Petunin, A. A.; Berezin, I. M.

2017-12-01

A problem of minimizing the length of the blank run for a cutting tool during cutting of sheet materials into shaped blanks is discussed. This problem arises during the preparation of control programs for computerized numerical control (CNC) machines. A discrete model of the problem is analogous in setting to the generalized travelling salesman problem with limitations in the form of precursor conditions determined by the technological features of cutting. A certain variant of a genetic algorithm for solving this problem is described. The effect of the parameters of the developed algorithm on the solution result for the problem with limitations is investigated.

Integral Method of Boundary Characteristics: Neumann Condition

NASA Astrophysics Data System (ADS)

Kot, V. A.

2018-05-01

A new algorithm, based on systems of identical equalities with integral and differential boundary characteristics, is proposed for solving boundary-value problems on the heat conduction in bodies canonical in shape at a Neumann boundary condition. Results of a numerical analysis of the accuracy of solving heat-conduction problems with variable boundary conditions with the use of this algorithm are presented. The solutions obtained with it can be considered as exact because their errors comprise hundredths and ten-thousandths of a persent for a wide range of change in the parameters of a problem.

Male Juveniles with Sexual Behavior Problems: Are There Differences among Racial Groups?

ERIC Educational Resources Information Center

Ikomi, Philip A.; Rodney, H. Elaine; McCoy, Tana

2009-01-01

This study used archival data on a sample of 186,492 referrals from a southwestern state Juvenile Probation Commission to compare the characteristics of 5,439 male Black, Hispanic, and White juveniles with sexual behavior problems on the five most common sexual offenses in the data set. The characteristics of 181,053 juveniles of the three races…

[Latent Class Analysis of Gambling Activities among Korean Adolescents].

PubMed

Kang, Kyonghwa; Kim, Hyeongsu; Park, Ae Ran; Kim, Hee Young; Lee, Kunsei

2018-04-01

The aim of this study is to identify the types of gambling among adolescents and provide basic prevention information regarding adolescents' gambling problems. Secondary data from representative national survey on 2015 Youth Gambling Problems of Korea Center on Gambling Problems were used. Using latent class analysis (LCA), 13 gambling types such as offline and online games of 14,011 adolescents were classified, and gambling experiences and characteristics were analyzed. The subgroups of adolescent gambling were identified as four latent classes: a rare group (84.5% of the sample), a risk group (1.0%), an offline group (11.9%), and an expanded group (2.6%). The types and characteristics of gambling among the latent classes differed. In the risk group, adolescents participated in online illegal sports betting and internet casino, and gambling time, gambling expenses, and the number of gambling types were higher than other groups. Gambling frequently occur among adolescent, and the subtypes of gambling did not reveal homogeneous characteristics. In order to prevent adolescent gambling problems, it is a necessary to develop tailored prevention intervention in the nursing field, which is appropriate to the characteristics of adolescent gambling group and can help with early identification. © 2018 Korean Society of Nursing Science.

Behavioral ecology of captive species: using behavioral adaptations to assess and enhance welfare of nonhuman zoo animals.

PubMed

Koene, Paul

2013-01-01

This project aimed to estimate a species' adaptations in nature and in captivity, assess welfare, suggest environmental changes, and find species characteristics that underlie welfare problems in nonhuman animals in the zoo. First, the current status of zoo animal welfare assessment was reviewed, and the behavioral ecology approach was outlined. In this approach, databases of species characteristics were developed using (a) literature of natural behavior and (b) captive behavior. Species characteristics were grouped in 8 functional behavioral ecological fitness-related categories: space, time, metabolic, safety, reproductive, comfort, social, and information adaptations. Assessments of the strength of behavioral adaptations in relation to environmental demands were made based on the results available from the literature. The databases with literature at the species level were coupled with databases of (c) behavioral observations and (d) welfare assessments under captive conditions. Observation and welfare assessment methods were adapted from the animal on the farm realm and applied to zoo species. It was expected that the comparison of the repertoire of behaviors in natural and captive environments would highlight welfare problems, provide solutions to welfare problems by environmental changes, and identify species characteristics underlying zoo animal welfare problems.

Characteristic Evolution and Matching

NASA Astrophysics Data System (ADS)

Winicour, Jeffrey

2012-01-01

I review the development of numerical evolution codes for general relativity based upon the characteristic initial-value problem. Progress in characteristic evolution is traced from the early stage of 1D feasibility studies to 2D-axisymmetric codes that accurately simulate the oscillations and gravitational collapse of relativistic stars and to current 3D codes that provide pieces of a binary black-hole spacetime. Cauchy codes have now been successful at simulating all aspects of the binary black-hole problem inside an artificially constructed outer boundary. A prime application of characteristic evolution is to extend such simulations to null infinity where the waveform from the binary inspiral and merger can be unambiguously computed. This has now been accomplished by Cauchy-characteristic extraction, where data for the characteristic evolution is supplied by Cauchy data on an extraction worldtube inside the artificial outer boundary. The ultimate application of characteristic evolution is to eliminate the role of this outer boundary by constructing a global solution via Cauchy-characteristic matching. Progress in this direction is discussed.

Differences in Characteristics of Asian American and White Problem Gamblers Calling a Gambling Helpline

PubMed Central

Barry, Declan T.; Steinberg, Marvin A.; Wu, Ran; Potenza, Marc N.

2009-01-01

Objective The characteristics of Asian American and white problem gamblers using a gambling helpline were examined to identify race-related differences. Method Logistic regression analyses were conducted on data obtained from callers to a gambling helpline serving Southern New England in 2000–2003, inclusive. Results Of the 144 phone calls used in the analyses, 72 were from Asian American callers and 72 were from white callers who were matched on gender, education, income, marital/cohabitation status, and age. Race-related differences were observed in forms of gambling problems, psychiatric problems secondary to gambling, substance use problems, and family history. Asian American gamblers were more likely to report suicide attempts related to gambling and problems with non-strategic gambling. White gamblers were more likely to report both casino and non-casino gambling problems and personal and familial alcohol use problems. High proportions of both groups reported problems with strategic gambling, gambling-related anxiety, family and financial problems secondary to gambling, financial debt, daily tobacco use, and a family history of problem gambling. Conclusions Race-related differences should be considered in optimizing prevention and treatment strategies related to problem gambling. PMID:19238123

Analytical Analyses of Spatial and Temporal Characteristics of Infiltrated Water for Managed Aquifer Recharge

NASA Astrophysics Data System (ADS)

Zlotnik, V. A.; Ledder, G.; Kacimov, A. R.

2014-12-01

Disposal of excessive runoff or treated sewage into wadis and ephemeral streams is a common practice and an important hydrological problem in many Middle Eastern countries. While chemical and biological properties of the injected treated wastewater may be different from those of the receiving aquifer, the density contrast between the two fluids can be small. Therefore, studies of the fluid interface for variable density fluids or water intrusion are not directly relevant in many Managed Aquifer Recharge (MAR) problems. Other factors, such as the transient nature of injection and lack of detailed aquifer information must be considered. The disposed water reaching the water table through the vadose zone creates groundwater mounds, deforms the original water table, and develops finite-size convex-concave lenses of treated water over receiving water. After cessation of infiltration, these mounds flatten, water levels become horizontal, and infiltrated water becomes fully embedded in the receiving aquifer. The shape of the treated water body is controlled by the aquifer parameters, the magnitude of ambient flow, and the duration, rate, and cyclicity of infiltration. In case of limited aquifer data, advective transport modeling offers the most appropriate tools for predicting plume shapes over time, but surprisingly little work has been done on this important 3D flow problem. We investigate the lateral and vertical spreading of infiltrated water combining techniques of spatial velocity analyses by Zlotnik and Ledder (1992, 1993) with particle tracking. This approach allows for evaluating the geometry of the plume and the protection zone, the flow development phases, and other temporal and spatial effects and results can be used in conditions of limited data availability and quality. (Funding was provided by the USAID, DAI Subcontract 1001624-12S-19745)

Design of physical and logical topologies with fault-tolerant ability in wavelength-routed optical network

NASA Astrophysics Data System (ADS)

Chen, Chunfeng; Liu, Hua; Fan, Ge

2005-02-01

In this paper we consider the problem of designing a network of optical cross-connects(OXCs) to provide end-to-end lightpath services to label switched routers (LSRs). Like some previous work, we select the number of OXCs as our objective. Compared with the previous studies, we take into account the fault-tolerant characteristic of logical topology. First of all, using a Prufer number randomly generated, we generate a tree. By adding some edges to the tree, we can obtain a physical topology which consists of a certain number of OXCs and fiber links connecting OXCs. It is notable that we for the first time limit the number of layers of the tree produced according to the method mentioned above. Then we design the logical topologies based on the physical topologies mentioned above. In principle, we will select the shortest path in addition to some consideration on the load balancing of links and the limitation owing to the SRLG. Notably, we implement the routing algorithm for the nodes in increasing order of the degree of the nodes. With regarding to the problem of the wavelength assignment, we adopt the heuristic algorithm of the graph coloring commonly used. It is clear our problem is computationally intractable especially when the scale of the network is large. We adopt the taboo search algorithm to find the near optimal solution to our objective. We present numerical results for up to 1000 LSRs and for a wide range of system parameters such as the number of wavelengths supported by each fiber link and traffic. The results indicate that it is possible to build large-scale optical networks with rich connectivity in a cost-effective manner, using relatively few but properly dimensioned OXCs.

The association of illness perceptions with physical and mental health in systemic sclerosis patients: an exploratory study.

PubMed

Arat, Seher; Verschueren, Patrick; De Langhe, Ellen; Smith, Vanessa; Vanthuyne, Marie; Diya, Luwis; Van den Heede, Koen; Blockmans, Daniel; De Keyser, Filip; Houssiau, Frédéric A; Westhovens, René

2012-03-01

The aim of the present study was to evaluate the association between illness perceptions and the ability to cope with physical and mental health problems in a large cohort of systemic sclerosis (SSc) patients. This was a cross-sectional study in 217 systemic sclerosis patients from the Belgian Systemic Sclerosis Cohort. Illness perception and coping were measured by the Revised Illness Perception Questionnaire and a coping questionnaire--the Coping Orientation of Problem Experience inventory (COPE). Physical and mental health-related quality of life was measured by the 36-item short-form health survey (SF-36), as were disease activity and several severity parameters. The relationship between illness perceptions and the ability to cope with physical/mental health problems was examined using multiple linear regression analysis. According to LeRoy's classification, 49 patients had limited SSc (lSSc), 129 had limited cutaneous SSc (lcSSc) and 39 had diffuse cutaneous SSc (dcSSc). Median disease duration was five years and the modified Rodnan skin score was 4. Good physical health was significantly associated with the lcSSc subtype and low disease activity (p < 0.01 and p < 0.05, respectively). The perception of 'serious consequences' and strong 'illness identity' correlated with poor physical health (p < 0.001). Good mental health was associated with low illness identity scores and low 'emotional response' scores (p < 0.001). Coping variables were less significantly correlated with physical and mental health compared with the illness perception items. Illness representations contribute more than classical disease characteristics to physical and mental health. Copyright © 2011 John Wiley & Sons, Ltd.

Targeting Persons With or At High Risk for Chronic Obstructive Pulmonary Disease by State-based Surveillance

PubMed Central

Pleasants, Roy A.; Heidari, Khosrow; Wheaton, Anne G.; Ohar, Jill A.; Strange, Charlie; Croft, Janet B.; Liao, Winston; Mannino, David M.; Kraft, Monica

2015-01-01

The Behavioral Risk Factor Surveillance System (BRFSS) survey is used to estimate chronic obstructive pulmonary disease (COPD) prevalence and could be expanded to describe respiratory symptoms in the general population and to characterize persons with or at high risk for the disease. Tobacco duration and respiratory symptom questions were added to the 2012 South Carolina BRFSS. Data concerning sociodemographics, chronic illnesses, health behaviors, and respiratory symptoms were collected in 9438 adults ≥ 35 years-old. Respondents were categorized as having COPD, high risk, or low risk for the disease. High risk was defined as no self-reported COPD, ≥ 10 years’ tobacco use, and ≥ 1 respiratory symptom (frequent productive cough or shortness of breath (SOB), or breathing problems affecting activities). Prevalence of self-reported and high-risk COPD were 9.1% and 8.0%, respectively. Overall, 17.3%, 10.6%, and 5.2% of all respondents reported activities limited by breathing problems, frequent productive cough, and frequent SOB, respectively. The high-risk group was more likely than the COPD group to report a productive cough and breathing problems limiting activities as well as being current smokers, male, and African-American. Health impairment was more severe in the COPD than the high-risk group, and both were worse than the low-risk group. Conclusions Persons at high risk for COPD share many, but not all, of the characteristics of persons diagnosed with the disease. Additional questions addressing smoking duration and respiratory symptoms in the BRFSS identifies groups at high risk for having or developing COPD who may benefit from smoking cessation and case-finding interventions. PMID:26367193

A Children of Twins Study of parental divorce and offspring psychopathology.

PubMed

D'Onofrio, Brian M; Turkheimer, Eric; Emery, Robert E; Maes, Hermine H; Silberg, Judy; Eaves, Lindon J

2007-07-01

Although parental divorce is associated with increased substance use and internalizing problems, experiencing the separation of one's parents may not cause these outcomes. The relations may be due to genetic or environmental selection factors, characteristics that lead to both marital separation and offspring functioning. We used the Children of Twins (CoT) Design to explore whether unmeasured genetic or environmental factors related to the twin parent, and measured characteristics of both parents, account for the association between parental divorce and offspring substance use and internalizing problems. The association between parental divorce and offspring substance use problems remained robust when controlling for genetic and environmental risk from the twin parent associated with parental divorce, and measured characteristics of both parents. The results do not prove, but are consistent with, a causal connection. In contrast, the analyses suggest that shared genetic liability in parents and their offspring accounts for the increased risk of internalizing problems in adult offspring from divorced families. The study illustrates that unmeasured genetic and environmental selection factors must be considered when studying parental divorce. In explaining associations between parental divorce and young-adult adjustment, our evidence suggests that selection versus causal mechanisms may operate differently for substance abuse (a causal relation) and internalizing problems (an artifact of selection). The CoT design only controls for the genetic and environmental characteristics of one parent; thus, additional genetically informed analyses are needed.

An Approach to Economic Dispatch with Multiple Fuels Based on Particle Swarm Optimization

NASA Astrophysics Data System (ADS)

Sriyanyong, Pichet

2011-06-01

Particle Swarm Optimization (PSO), a stochastic optimization technique, shows superiority to other evolutionary computation techniques in terms of less computation time, easy implementation with high quality solution, stable convergence characteristic and independent from initialization. For this reason, this paper proposes the application of PSO to the Economic Dispatch (ED) problem, which occurs in the operational planning of power systems. In this study, ED problem can be categorized according to the different characteristics of its cost function that are ED problem with smooth cost function and ED problem with multiple fuels. Taking the multiple fuels into account will make the problem more realistic. The experimental results show that the proposed PSO algorithm is more efficient than previous approaches under consideration as well as highly promising in real world applications.

A systematic review of interventions conducted in clinical or community settings to improve dual-task postural control in older adults

PubMed Central

Agmon, Maayan; Belza, Basia; Nguyen, Huong Q; Logsdon, Rebecca G; Kelly, Valerie E

2014-01-01

Background Injury due to falls is a major problem among older adults. Decrements in dual-task postural control performance (simultaneously performing two tasks, at least one of which requires postural control) have been associated with an increased risk of falling. Evidence-based interventions that can be used in clinical or community settings to improve dual-task postural control may help to reduce this risk. Purpose The aims of this systematic review are: 1) to identify clinical or community-based interventions that improved dual-task postural control among older adults; and 2) to identify the key elements of those interventions. Data sources Studies were obtained from a search conducted through October 2013 of the following electronic databases: PubMed, CINAHL, PsycINFO, and Web of Science. Study selection Randomized and nonrandomized controlled studies examining the effects of interventions aimed at improving dual-task postural control among community-dwelling older adults were selected. Data extraction All studies were evaluated based on methodological quality. Intervention characteristics including study purpose, study design, and sample size were identified, and effects of dual-task interventions on various postural control and cognitive outcomes were noted. Data synthesis Twenty-two studies fulfilled the selection criteria and were summarized in this review to identify characteristics of successful interventions. Limitations The ability to synthesize data was limited by the heterogeneity in participant characteristics, study designs, and outcome measures. Conclusion Dual-task postural control can be modified by specific training. There was little evidence that single-task training transferred to dual-task postural control performance. Further investigation of dual-task training using standardized outcome measurements is needed. PMID:24741296

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

Wosnik, Martin; Bachant, Pete; Neary, Vincent Sinclair

CACTUS, developed by Sandia National Laboratories, is an open-source code for the design and analysis of wind and hydrokinetic turbines. While it has undergone extensive validation for both vertical axis and horizontal axis wind turbines, and it has been demonstrated to accurately predict the performance of horizontal (axial-flow) hydrokinetic turbines, its ability to predict the performance of crossflow hydrokinetic turbines has yet to be tested. The present study addresses this problem by comparing the predicted performance curves derived from CACTUS simulations of the U.S. Department of Energy’s 1:6 scale reference model crossflow turbine to those derived by experimental measurements inmore » a tow tank using the same model turbine at the University of New Hampshire. It shows that CACTUS cannot accurately predict the performance of this crossflow turbine, raising concerns on its application to crossflow hydrokinetic turbines generally. The lack of quality data on NACA 0021 foil aerodynamic (hydrodynamic) characteristics over the wide range of angles of attack (AoA) and Reynolds numbers is identified as the main cause for poor model prediction. A comparison of several different NACA 0021 foil data sources, derived using both physical and numerical modeling experiments, indicates significant discrepancies at the high AoA experienced by foils on crossflow turbines. Users of CACTUS for crossflow hydrokinetic turbines are, therefore, advised to limit its application to higher tip speed ratios (lower AoA), and to carefully verify the reliability and accuracy of their foil data. Accurate empirical data on the aerodynamic characteristics of the foil is the greatest limitation to predicting performance for crossflow turbines with semi-empirical models like CACTUS. Future improvements of CACTUS for crossflow turbine performance prediction will require the development of accurate foil aerodynamic characteristic data sets within the appropriate ranges of Reynolds numbers and AoA.« less

A characteristic based volume penalization method for general evolution problems applied to compressible viscous flows

NASA Astrophysics Data System (ADS)

Brown-Dymkoski, Eric; Kasimov, Nurlybek; Vasilyev, Oleg V.

2014-04-01

In order to introduce solid obstacles into flows, several different methods are used, including volume penalization methods which prescribe appropriate boundary conditions by applying local forcing to the constitutive equations. One well known method is Brinkman penalization, which models solid obstacles as porous media. While it has been adapted for compressible, incompressible, viscous and inviscid flows, it is limited in the types of boundary conditions that it imposes, as are most volume penalization methods. Typically, approaches are limited to Dirichlet boundary conditions. In this paper, Brinkman penalization is extended for generalized Neumann and Robin boundary conditions by introducing hyperbolic penalization terms with characteristics pointing inward on solid obstacles. This Characteristic-Based Volume Penalization (CBVP) method is a comprehensive approach to conditions on immersed boundaries, providing for homogeneous and inhomogeneous Dirichlet, Neumann, and Robin boundary conditions on hyperbolic and parabolic equations. This CBVP method can be used to impose boundary conditions for both integrated and non-integrated variables in a systematic manner that parallels the prescription of exact boundary conditions. Furthermore, the method does not depend upon a physical model, as with porous media approach for Brinkman penalization, and is therefore flexible for various physical regimes and general evolutionary equations. Here, the method is applied to scalar diffusion and to direct numerical simulation of compressible, viscous flows. With the Navier-Stokes equations, both homogeneous and inhomogeneous Neumann boundary conditions are demonstrated through external flow around an adiabatic and heated cylinder. Theoretical and numerical examination shows that the error from penalized Neumann and Robin boundary conditions can be rigorously controlled through an a priori penalization parameter η. The error on a transient boundary is found to converge as O(η), which is more favorable than the error convergence of the already established Dirichlet boundary condition.

Application of adenylate energy charge to problems of environmental impact assessment in aquatic organisms

NASA Astrophysics Data System (ADS)

Ivanovici, A. M.

1980-03-01

Various physiological and biochemical methods have been proposed for assessing the effects of environmental perturbation on aquatic organisms. The success of these methods as diagnostic tools has, however, been limited. This paper proposes that adenylate energy charge overcomes some of these limitations. The adenylate energy charge (AEC) is calculated from concentrations of adenine nucleotides ([ATP+½ADP]/[ATP+ADP+AMP]), and is a reflection of metabolic potential available to an organism. Several features of this method are: correlation of specific values with physiological condition or growth state, a defined range of values, fast response times and high precision. Several examples from laboratory and field experiments are given to demonstrate these features. The test organisms used (mollusc species) were exposed to a variety of environmental perturbations, including salinity reduction, hydrocarbons and low doses of heavy metal. The studies performed indicate that the energy charge may be a useful measure in the assessment of environmental impact. Its use is restricted, however, as several limitations exist which need to be fully evaluated. Further work relating values to population characteristics of multicellular organisms needs to be completed before the method can become a predictive tool for management.

Dental cone-beam CT reconstruction from limited-angle view data based on compressed-sensing (CS) theory for fast, low-dose X-ray imaging

NASA Astrophysics Data System (ADS)

Je, Uikyu; Cho, Hyosung; Lee, Minsik; Oh, Jieun; Park, Yeonok; Hong, Daeki; Park, Cheulkyu; Cho, Heemoon; Choi, Sungil; Koo, Yangseo

2014-06-01

Recently, reducing radiation doses has become an issue of critical importance in the broader radiological community. As a possible technical approach, especially, in dental cone-beam computed tomography (CBCT), reconstruction from limited-angle view data (< 360°) would enable fast scanning with reduced doses to the patient. In this study, we investigated and implemented an efficient reconstruction algorithm based on compressed-sensing (CS) theory for the scan geometry and performed systematic simulation works to investigate the image characteristics. We also performed experimental works by applying the algorithm to a commercially-available dental CBCT system to demonstrate its effectiveness for image reconstruction in incomplete data problems. We successfully reconstructed CBCT images with incomplete projections acquired at selected scan angles of 120, 150, 180, and 200° with a fixed angle step of 1.2° and evaluated the reconstruction quality quantitatively. Both simulation and experimental demonstrations of the CS-based reconstruction from limited-angle view data show that the algorithm can be applied directly to current dental CBCT systems for reducing the imaging doses and further improving the image quality.

Performance characteristics of a visual-search human-model observer with sparse PET image data

NASA Astrophysics Data System (ADS)

Gifford, Howard C.

2012-02-01

As predictors of human performance in detection-localization tasks, statistical model observers can have problems with tasks that are primarily limited by target contrast or structural noise. Model observers with a visual-search (VS) framework may provide a more reliable alternative. This framework provides for an initial holistic search that identifies suspicious locations for analysis by a statistical observer. A basic VS observer for emission tomography focuses on hot "blobs" in an image and uses a channelized nonprewhitening (CNPW) observer for analysis. In [1], we investigated this model for a contrast-limited task with SPECT images; herein, a statisticalnoise limited task involving PET images is considered. An LROC study used 2D image slices with liver, lung and soft-tissue tumors. Human and model observers read the images in coronal, sagittal and transverse display formats. The study thus measured the detectability of tumors in a given organ as a function of display format. The model observers were applied under several task variants that tested their response to structural noise both at the organ boundaries alone and over the organs as a whole. As measured by correlation with the human data, the VS observer outperformed the CNPW scanning observer.

General Linearized Theory of Quantum Fluctuations around Arbitrary Limit Cycles

NASA Astrophysics Data System (ADS)

Navarrete-Benlloch, Carlos; Weiss, Talitha; Walter, Stefan; de Valcárcel, Germán J.

2017-09-01

The theory of Gaussian quantum fluctuations around classical steady states in nonlinear quantum-optical systems (also known as standard linearization) is a cornerstone for the analysis of such systems. Its simplicity, together with its accuracy far from critical points or situations where the nonlinearity reaches the strong coupling regime, has turned it into a widespread technique, being the first method of choice in most works on the subject. However, such a technique finds strong practical and conceptual complications when one tries to apply it to situations in which the classical long-time solution is time dependent, a most prominent example being spontaneous limit-cycle formation. Here, we introduce a linearization scheme adapted to such situations, using the driven Van der Pol oscillator as a test bed for the method, which allows us to compare it with full numerical simulations. On a conceptual level, the scheme relies on the connection between the emergence of limit cycles and the spontaneous breaking of the symmetry under temporal translations. On the practical side, the method keeps the simplicity and linear scaling with the size of the problem (number of modes) characteristic of standard linearization, making it applicable to large (many-body) systems.

Barriers to the Identification and Management of Psychosocial Problems: Changes from 2004 to 2013

PubMed Central

Horwitz, Sarah McCue; Storfer-Isser, Amy; Kerker, Bonnie D.; Szilagyi, Moira; Garner, Andrew; O’Connor, Karen G.; Hoagwood, Kimberly E.; Stein, Ruth E.K.

2015-01-01

Objective Pediatricians report many barriers to caring for children with mental health (MH) problems. The American Academy of Pediatrics (AAP) has focused attention on MH problems but the impact on perceived barriers is unknown. We examined whether perceived barriers and their correlates changed from 2004 to 2013. Methods In 2004, 832/1600 (52%) and in 2013, 594/1617 (36.7%) of randomly selected AAP members surveyed responded to Periodic Surveys, answering questions about socio-demographics, practice characteristics, and 7 barriers to identifying, treating/managing and referring child/adolescent MH problems. To reduce non-response bias, weighted descriptive and logistic regression analyses were conducted. Results Lack of training in treatment of child MH problems (~65%) and lack of confidence treating children with counseling (~60%) did not differ across surveys. Five barriers (lack of training in identifying MH problems, lack of confidence diagnosing, lack of confidence treating with medications, inadequate reimbursement and lack of time) were less frequently endorsed in 2013 (all p<.01), although lack of time was still endorsed by 70% in 2013. In 2004, 34% of pediatricians endorsed 6 or 7 barriers compared to 26% in 2013 (p<.005). Practicing general pediatrics exclusively was associated with endorsing 6 or 7 barriers in both years (p <.001). Conclusion Although fewer barriers were endorsed in 2013, most pediatricians believe that they have inadequate training in treating child MH problems, a lack of confidence to counsel children, and limited time for these problems. These findings suggest significant barriers still exist, highlighting the need for improved developmental and behavioral pediatrics training. What’s New This study compares reported barriers from the 2004 and 2013 Periodic Surveys. Although pediatricians report fewer barriers in 2013, 66% continue to report lack of training in counseling or medication of children with MH problems, suggesting deficits in developmental and behavioral pediatrics training. PMID:26409303

Therapist-delivered and self-help interventions for gambling problems: A review of contents.

PubMed

Rodda, Simone; Merkouris, Stephanie S; Abraham, Charles; Hodgins, David C; Cowlishaw, Sean; Dowling, Nicki A

2018-06-13

Background and aims To date, no systematic approach to identifying the content and characteristics of psychological interventions used to reduce gambling or problem gambling has been developed. This study aimed to develop a reliable classification system capable of identifying intervention characteristics that could, potentially, account for greater or lesser effectiveness. Methods Intervention descriptions were content analyzed to identify common and differentiating characteristics. A coder manual was developed and applied by three independent coders to identify the presence or absence of defined characteristics in 46 psychological and self-help gambling interventions. Results The final classification taxonomy, entitled Gambling Intervention System of CharacTerization (GIST), included 35 categories of intervention characteristics. These were assigned to four groups: (a) types of change techniques (18 categories; e.g., cognitive restructuring and relapse prevention), (b) participant and study characteristics (6 categories; e.g., recruitment strategy and remuneration policy), and (c) characteristics of the delivery and conduct of interventions (11 categories; e.g., modality of delivery and therapist involvement), and (d) evaluation characteristics (e.g., type of control group). Interrater reliability of identification of defined characteristics was high (κ = 0.80-1.00). Discussion This research provides a tool that allows systematic identification of intervention characteristics, thereby enabling consideration, not only of whether interventions are effective or not, but also of which domain-relevant characteristics account for greater or lesser effectiveness. The taxonomy also facilitates standardized description of intervention content in a field in which many diverse interventions have been evaluated. Conclusion Application of this coding tool has the potential to accelerate the development of more efficient and effective therapist-delivered and self-directed interventions to reduce gambling problems.

Statistical distribution sampling

NASA Technical Reports Server (NTRS)

Johnson, E. S.

1975-01-01

Determining the distribution of statistics by sampling was investigated. Characteristic functions, the quadratic regression problem, and the differential equations for the characteristic functions are analyzed.

Analysis of Slope Limiters on Irregular Grids

NASA Technical Reports Server (NTRS)

Berger, Marsha; Aftosmis, Michael J.

2005-01-01

This paper examines the behavior of flux and slope limiters on non-uniform grids in multiple dimensions. Many slope limiters in standard use do not preserve linear solutions on irregular grids impacting both accuracy and convergence. We rewrite some well-known limiters to highlight their underlying symmetry, and use this form to examine the proper - ties of both traditional and novel limiter formulations on non-uniform meshes. A consistent method of handling stretched meshes is developed which is both linearity preserving for arbitrary mesh stretchings and reduces to common limiters on uniform meshes. In multiple dimensions we analyze the monotonicity region of the gradient vector and show that the multidimensional limiting problem may be cast as the solution of a linear programming problem. For some special cases we present a new directional limiting formulation that preserves linear solutions in multiple dimensions on irregular grids. Computational results using model problems and complex three-dimensional examples are presented, demonstrating accuracy, monotonicity and robustness.

Cored density profiles in the DARKexp model

NASA Astrophysics Data System (ADS)

Destri, Claudio

2018-05-01

The DARKexp model represents a novel and promising attempt to solve a long standing problem of statistical mechanics, that of explaining from first principles the quasi-stationary states at the end of the collisionless gravitational collapse. The model, which yields good fits to observation and simulation data on several scales, was originally conceived to provide a theoretical basis for the 1/r cusp of the Navarro-Frenk-White profile. In this note we show that it also allows for cored density profiles that, when viewed in three dimensions, in the r→0 limit have the conical shape characteristic of the Burkert profile. It remains to be established whether both cusps and cores, or only one of the two types, are allowed beyond the asymptotic analysis of this work.

A study of interactive control scheduling and economic assessment for robotic systems

NASA Technical Reports Server (NTRS)

1982-01-01

A class of interactive control systems is derived by generalizing interactive manipulator control systems. Tasks of interactive control systems can be represented as a network of a finite set of actions which have specific operational characteristics and specific resource requirements, and which are of limited duration. This has enabled the decomposition of the overall control algorithm simultaneously and asynchronously. The performance benefits of sensor referenced and computer-aided control of manipulators in a complex environment is evaluated. The first phase of the CURV arm control system software development and the basic features of the control algorithms and their software implementation are presented. An optimal solution for a production scheduling problem that will be easy to implement in practical situations is investigated.

Shatter cones - An outstanding problem in shock mechanics. [geological impact fracture surface in cratering

NASA Technical Reports Server (NTRS)

Milton, D. J.

1977-01-01

Shatter cone characteristics are surveyed. Shatter cones, a form of rock fracture in impact structures, apparently form as a shock front interacts with inhomogeneities or discontinuities in the rock. Topics discussed include morphology, conditions of formation, shock pressure of formation, and theories of formation. It is thought that shatter cones are produced within a limited range of shock pressures extending from about 20 to perhaps 250 kbar. Apical angles range from less than 70 deg to over 120 deg. Tentative hypotheses concerning the physical process of shock coning are considered. The range in shock pressures which produce shatter cones might correspond to the range in which shock waves decompose into elastic and deformational fronts.

Behavioral health problems, ex-offender reentry policies, and the "Second Chance Act".

PubMed

Pogorzelski, Wendy; Wolff, Nancy; Pan, Ko-Yu; Blitz, Cynthia L

2005-10-01

The federal "Second Chance Act of 2005" calls for expanding reentry services for people leaving prison, yet existing policies restrict access to needed services for those with criminal records. We examined the interaction between individual-level characteristics and policy-level restrictions related to criminal conviction, and the likely effects on access to resources upon reentry, using a sample of prisoners with Axis I mental disorders (n=3073). We identified multiple challenges related to convictions, including restricted access to housing, public assistance, and other resources. Invisible punishments embedded within existing policies were inconsistent with the call for second chances. Without modification of federal and state policies, the ability of reentry services to foster behavioral health and community reintegration is limited.

Strain-Based Damage Determination Using Finite Element Analysis for Structural Health Management

NASA Technical Reports Server (NTRS)

Hochhalter, Jacob D.; Krishnamurthy, Thiagaraja; Aguilo, Miguel A.

2016-01-01

A damage determination method is presented that relies on in-service strain sensor measurements. The method employs a gradient-based optimization procedure combined with the finite element method for solution to the forward problem. It is demonstrated that strains, measured at a limited number of sensors, can be used to accurately determine the location, size, and orientation of damage. Numerical examples are presented to demonstrate the general procedure. This work is motivated by the need to provide structural health management systems with a real-time damage characterization. The damage cases investigated herein are characteristic of point-source damage, which can attain critical size during flight. The procedure described can be used to provide prognosis tools with the current damage configuration.

Faradaurate nanomolecules: a superstable plasmonic 76.3 kDa cluster.

PubMed

Dass, Amala

2011-12-07

Information on the emergence of the characteristic plasmonic optical properties of nanoscale noble-metal particles has been limited, due in part to the problem of preparing homogeneous material for ensemble measurements. Here, we report the identification, isolation, and mass spectrometric and optical characterization of a 76.3 kDa thiolate-protected gold nanoparticle. This giant molecule is far larger than any metal-cluster compound, those with direct metal-to-metal bonding, previously known as homogeneous molecular substances, and is the first to exhibit clear plasmonic properties. The observed plasmon emergence phenomena in nanomolecules are of great interest, and the availability of absolutely homogeneous and characterized samples is thus critical to establishing their origin. © 2011 American Chemical Society

Analytical Approach to Large Deformation Problems of Frame Structures

NASA Astrophysics Data System (ADS)

Ohtsuki, Atsumi; Ellyin, Fernand

In elements used as flexible linking devices and structures, the main characteristic is a fairly large deformation without exceeding the elastic limit of the material. This property is of both analytical and technological interests. Previous studies of large deformation have been generally concerned with a single member (e.g. a cantilever beam, a simply supported beam, etc.). However, there are very few large deformation studies of assembled members such as frames. This paper deals with a square frame with rigid joints, loaded diagonally in either tension or compression by a pair of opposite forces. Analytical solutions for large deformation are obtained in terms of elliptic integrals, and are compared with the experimental data. The agreement is found to be fairly close.

Impact of neonatal risk and temperament on behavioral problems in toddlers born preterm.

PubMed

Guilherme Monte Cassiano, Rafaela; Gaspardo, Claudia Maria; Cordaro Bucker Furini, Guilherme; Martinez, Francisco Eulogio; Martins Linhares, Maria Beatriz

2016-12-01

Children born preterm are at risk for later developmental disorders. The present study examined the predictive effects of neonatal, sociodemographic, and temperament characteristics on behavioral outcomes at toddlerhood, in children born preterm. The sample included 100 toddlers born preterm and with very-low-birth-weight, and their mothers. Neonatal characteristics were evaluated using medical records. The mothers were interviewed using the Early Childhood Behavior Questionnaire for temperament assessment, and the Child Behavior Checklist for behavioral assessment. Multiple linear regression analyses were performed. Predictors of 39% of the variability of the total behavioral problems in toddlers born prematurely were: temperament with more Negative Affectivity and less Effortful Control, lower family socioeconomic status, and younger mothers at childbirth. Temperament with more Negative Affectivity and less Effortful Control and lower family socioeconomic status were predictors of 23% of the variability of internalizing behavioral problems. Additionally, 37% of the variability of externalizing behavioral problems was explained by temperament with more Negative Affectivity and less Effortful Control, and younger mothers at childbirth. The neonatal characteristics and stressful events in the neonatal intensive care unit did not predict behavioral problems at toddlerhood. However, temperament was a consistent predictor of behavioral problems in toddlers born preterm. Preventive follow-up programs could assess dispositional traits of temperament to provide early identification of preterm infants at high-risk for behavioral problems. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Enhancing quantum annealing performance for the molecular similarity problem

NASA Astrophysics Data System (ADS)

Hernandez, Maritza; Aramon, Maliheh

2017-05-01

Quantum annealing is a promising technique which leverages quantum mechanics to solve hard optimization problems. Considerable progress has been made in the development of a physical quantum annealer, motivating the study of methods to enhance the efficiency of such a solver. In this work, we present a quantum annealing approach to measure similarity among molecular structures. Implementing real-world problems on a quantum annealer is challenging due to hardware limitations such as sparse connectivity, intrinsic control error, and limited precision. In order to overcome the limited connectivity, a problem must be reformulated using minor-embedding techniques. Using a real data set, we investigate the performance of a quantum annealer in solving the molecular similarity problem. We provide experimental evidence that common practices for embedding can be replaced by new alternatives which mitigate some of the hardware limitations and enhance its performance. Common practices for embedding include minimizing either the number of qubits or the chain length and determining the strength of ferromagnetic couplers empirically. We show that current criteria for selecting an embedding do not improve the hardware's performance for the molecular similarity problem. Furthermore, we use a theoretical approach to determine the strength of ferromagnetic couplers. Such an approach removes the computational burden of the current empirical approaches and also results in hardware solutions that can benefit from simple local classical improvement. Although our results are limited to the problems considered here, they can be generalized to guide future benchmarking studies.

Problem-solving variability in older spouses: how is it linked to problem-, person-, and couple-characteristics?

PubMed

Hoppmann, Christiane A; Blanchard-Fields, Fredda

2011-09-01

Problem-solving does not take place in isolation and often involves social others such as spouses. Using repeated daily life assessments from 98 older spouses (M age = 72 years; M marriage length = 42 years), the present study examined theoretical notions from social-contextual models of coping regarding (a) the origins of problem-solving variability and (b) associations between problem-solving and specific problem-, person-, and couple- characteristics. Multilevel models indicate that the lion's share of variability in everyday problem-solving is located at the level of the problem situation. Importantly, participants reported more proactive emotion regulation and collaborative problem-solving for social than nonsocial problems. We also found person-specific consistencies in problem-solving. That is, older spouses high in Neuroticism reported more problems across the study period as well as less instrumental problem-solving and more passive emotion regulation than older spouses low in Neuroticism. Contrary to expectations, relationship satisfaction was unrelated to problem-solving in the present sample. Results are in line with the stress and coping literature in demonstrating that everyday problem-solving is a dynamic process that has to be viewed in the broader context in which it occurs. Our findings also complement previous laboratory-based work on everyday problem-solving by underscoring the benefits of examining everyday problem-solving as it unfolds in spouses' own environment.

Task five report: Laser communications for data acquisition networks. [characteristics of lasers and laser systems for optical communication applications

NASA Technical Reports Server (NTRS)

1973-01-01

Laser communication technology and laser communication performance are reviewed. The subjects discussed are: (1) characteristics of laser communication systems, (2) laser technology problems, (3) means of overcoming laser technology problems, and (4) potential schedule for including laser communications into data acquisition networks. Various types of laser communication systems are described and their capabilities are defined.

The Screening Tool of Feeding Problems Applied to Children (STEP-CHILD): Psychometric Characteristics and Associations with Child and Parent Variables

ERIC Educational Resources Information Center

Seiverling, Laura; Hendy, Helen M.; Williams, Keith

2011-01-01

The present study evaluated the 23-item Screening Tool for Feeding Problems (STEP; Matson & Kuhn, 2001) with a sample of children referred to a hospital-based feeding clinic to examine the scale's psychometric characteristics and then demonstrate how a children's revision of the STEP, the STEP-CHILD is associated with child and parent variables.…

Teachers' and Students' Perceptions of Effective Physics Teacher Characteristics

ERIC Educational Resources Information Center

Korur, Fikret; Eryilmaz, Ali

2012-01-01

Problem Statement: What do teachers and students in Turkey perceive as the common characteristics of effective physics teachers? Purpose of Study: The first aim was to investigate the common characteristics of effective physics teachers by asking students and teachers about the effects of teacher characteristics on student physics achievement and…

A method of intentional movement estimation of oblique small-UAV videos stabilized based on homography model

NASA Astrophysics Data System (ADS)

Guo, Shiyi; Mai, Ying; Zhao, Hongying; Gao, Pengqi

2013-05-01

The airborne video streams of small-UAVs are commonly plagued with distractive jittery and shaking motions, disorienting rotations, noisy and distorted images and other unwanted movements. These problems collectively make it very difficult for observers to obtain useful information from the video. Due to the small payload of small-UAVs, it is a priority to improve the image quality by means of electronic image stabilization. But when small-UAV makes a turn, affected by the flight characteristics of it, the video is easy to become oblique. This brings a lot of difficulties to electronic image stabilization technology. Homography model performed well in the oblique image motion estimation, while bringing great challenges to intentional motion estimation. Therefore, in this paper, we focus on solve the problem of the video stabilized when small-UAVs banking and turning. We attend to the small-UAVs fly along with an arc of a fixed turning radius. For this reason, after a series of experimental analysis on the flight characteristics and the path how small-UAVs turned, we presented a new method to estimate the intentional motion in which the path of the frame center was used to fit the video moving track. Meanwhile, the image sequences dynamic mosaic was done to make up for the limited field of view. At last, the proposed algorithm was carried out and validated by actual airborne videos. The results show that the proposed method is effective to stabilize the oblique video of small-UAVs.

Understanding Adult Age Differences in the Frequency of Problems With Friends.

PubMed

Schlosnagle, Leo; Strough, JoNell

2017-01-01

We investigated characteristics of younger and older adults' friendships. Younger (N = 39) and older (N = 39) adults completed measures pertaining to a specific friend they had (i.e., contact frequency, positive friendship quality, and negative friendship quality) and their frequency of problems with friends in general. Older adults reported fewer problems with friends in general, and fewer negative friendship qualities, less frequent contact, and more positive friendship qualities with a specific friend than younger adults. Contact frequency, positive friendship quality, and negative friendship quality with a specific friend were related to frequency of problems with friends in general, but only contact frequency was a significant mediator of the relation between age and frequency of problems with friends in general. Results show that characteristics of a specific friendship relate to problems with friends in general, and that contact frequency with a specific friend mediates the relation between age and problems with friends in general. Implications are discussed. © The Author(s) 2016.

Role of Parent and Peer Relationships and Individual Characteristics in Middle School Children's Behavioral Outcomes in the Face of Community Violence

PubMed Central

Salzinger, Suzanne; Rosario, Margaret; Feldman, Richard S.; Ng-Mak, Daisy S.

2010-01-01

This study examines processes linking inner-city community violence exposure to subsequent internalizing and externalizing problems. Hypothesized risk and protective factors from three ecological domains -- children's parent and peer relationships and individual characteristics -- were examined for mediating, moderating or independent roles in predicting problem behavior among 667 children over three years of middle school. Mediation was not found. However, parent and peer variables moderated the association between exposure and internalizing problems. Under high exposure, normally protective factors (e.g., attachment to parents) were less effective in mitigating exposure's effects than under low exposure; attachment to friends was more effective. Individual competence was independently associated with decreased internalizing problems. Variables from all domains, and exposure, were independently associated with externalizing problems. Protective factors (e.g., parent attachment) predicted decreased problems; risk factors (e.g., friends' delinquency) predicted increased problems. Results indicate community violence reduction as essential in averting inner-city adolescents' poor behavioral outcomes. PMID:21643493

Study on the integration of layered water injection technology and subdivision adjustment

NASA Astrophysics Data System (ADS)

Zhang, Yancui

2018-06-01

With oil many infillings, thin and poor reservoir exploitation changes gradually to low permeability, thin and poor reservoir development characteristics of multiple layers thickness, low permeability, in the actual development process, the General Department of oil layers of encryption perforation long thin and poor mining, interlayer contradiction more prominent, by conventional layered water injection that can alleviate the contradiction between layers to a certain extent, by the injection interval and other factors can not fundamentally solve the problem, leading to the potential well area key strata or layers is difficult to determine, the layering test and slicing technology is difficult to adapt to the need of tap water control block. This paper through numerical simulation using the conceptual model and the actual block, it has a great influence on the low permeability reservoir of different stratified water permeability combination of permeability technology and application limits, profit and loss balance principle, low oil prices on the lower series of subdivision technical and economic limit, so the reservoir subdivision reorganization, narrow wells mining, reduce the interference between layers, from the maximum fundamental improvement of layered water injection efficiency. At the same time, in order to meet the needs of reservoir subdivision adjustment, subdividing distance with water, a small interlayer wells subdivision technology for further research in the pickup, solved using two ordinary bridge eccentric water regulator with injection of two layers, by throwing exercise distance limit card from the larger problem, the water distribution card size from 7.0m to 1.0m, and the testing efficiency is improved, and provide technical support for further subdivision water injection wells.

Conditioning of participation of disabled males and females from eastern regions of Poland in tourism and recreation.

PubMed

Bergier, Józef; Dąbrowski, Dominik; Zbikowski, Jarosław

2011-01-01

Disability is a serious social, cultural and economic problem, the solving of which requires both legal regulations and coordinated activities by the State. A constantly increasing number of the disabled is an important premise for undertaking actions aimed at complex rehabilitation of this population group, and their engagement in social and economic life. Creating possibilities for spending free time in an attractive way, in accordance with ones interests and needs, is an essential area of rehabilitation activities. In 2005, the Institute of Tourism and Recreation at the State Higher Vocational School in Biał Podlaska launched representative, complex studies concerning the social conditioning of involvement of the disabled from the regions of Eastern Poland in tourism and mobile recreation. The presented material is an excerpt from this study report. It concerns barriers which limit or make it impossible for disabled males and females to participate in tourism and mobile recreation in the regions of Lublin, Rzeszow, and Białstok. Among barriers, which to the highest degree limit the participation of the disabled in tourism and recreation, the respondents indicated their poor material standard. Other important barriers were inconveniences associated with transport, lack of up-to-date information, and type of disability. The barriers limiting motor activity were also analyzed according to gender. Statistically significant differences were observed between males and females with respect to the following characteristics: transport, lack of adequate information, lack of off er of activities, and lack of assistance. It is noteworthy that males more strongly than females emphasized such barriers as lack of information, off er of assistance, while females indicated the problems with transport.

Numerical simulations of strongly correlated electron and spin systems

NASA Astrophysics Data System (ADS)

Changlani, Hitesh Jaiprakash

Developing analytical and numerical tools for strongly correlated systems is a central challenge for the condensed matter physics community. In the absence of exact solutions and controlled analytical approximations, numerical techniques have often contributed to our understanding of these systems. Exact Diagonalization (ED) requires the storage of at least two vectors the size of the Hilbert space under consideration (which grows exponentially with system size) which makes it affordable only for small systems. The Density Matrix Renormalization Group (DMRG) uses an intelligent Hilbert space truncation procedure to significantly reduce this cost, but in its present formulation is limited to quasi-1D systems. Quantum Monte Carlo (QMC) maps the Schrodinger equation to the diffusion equation (in imaginary time) and only samples the eigenvector over time, thereby avoiding the memory limitation. However, the stochasticity involved in the method gives rise to the "sign problem" characteristic of fermion and frustrated spin systems. The first part of this thesis is an effort to make progress in the development of a numerical technique which overcomes the above mentioned problems. We consider novel variational wavefunctions, christened "Correlator Product States" (CPS), that have a general functional form which hopes to capture essential correlations in the ground states of spin and fermion systems in any dimension. We also consider a recent proposal to modify projector (Green's Function) Quantum Monte Carlo to ameliorate the sign problem for realistic and model Hamiltonians (such as the Hubbard model). This exploration led to our own set of improvements, primarily a semistochastic formulation of projector Quantum Monte Carlo. Despite their limitations, existing numerical techniques can yield physical insights into a wide variety of problems. The second part of this thesis considers one such numerical technique - DMRG - and adapts it to study the Heisenberg antiferromagnet on a generic tree graph. Our attention turns to a systematic numerical and semi-analytical study of the effect of local even/odd sublattice imbalance on the low energy spectrum of antiferromagnets on regular Cayley trees. Finally, motivated by previous experiments and theories of randomly diluted antiferromagnets (where an even/odd sublattice imbalance naturally occurs), we present our study of the Heisenberg antiferromagnet on the Cayley tree at the percolation threshold. Our work shows how to detect "emergent" low energy degrees of freedom and compute the effective interactions between them by using data from DMRG calculations.

Renal and urologic manifestations of pediatric condition falsification/Munchausen by proxy.

PubMed

Feldman, Kenneth W; Feldman, Marc D; Grady, Richard; Burns, Mark W; McDonald, Ruth

2007-06-01

Renal and urologic problems in pediatric condition falsification (PCF)/Munchausen by proxy (MBP) can pose frustrating diagnostic and management problems. Five previously unreported victims of PCF/MBP are described. Symptoms included artifactual hematuria, recalcitrant urinary infections, dysfunctional voiding, perineal irritation, glucosuria, and "nutcracker syndrome", in addition to alleged sexual abuse. Falsifications included false or exaggerated history, specimen contamination, and induced illness. Caretakers also intentionally withheld appropriately prescribed treatment. Children underwent invasive diagnostic and surgical procedures because of the falsifications. They developed iatrogenic complications as well as behavioral problems stemming from their abuse. A PCF/MBP database was started in 1995 and includes the characteristics of 135 PCF/MBP victims examined by the first author between 1974 and 2006. Analysis of the database revealed that 25% of the children had renal or urologic issues. They were the presenting/primary issue for five. Diagnosis of PCF/MBP was delayed an average of 4.5 years from symptom onset. Almost all patients were victimized by their mothers, and maternal health falsification and somatization were common. Thirty-one of 34 children had siblings who were also victimized, six of whom died. In conclusion, falsifications of childhood renal and urologic illness are relatively uncommon; however, the deceits are prolonged and tortuous. Early recognition and intervention might limit the harm.

On the numerical modeling of sliding beams: A comparison of different approaches

NASA Astrophysics Data System (ADS)

Steinbrecher, Ivo; Humer, Alexander; Vu-Quoc, Loc

2017-11-01

The transient analysis of sliding beams represents a challenging problem of structural mechanics. Typically, the sliding motion superimposed by large flexible deformation requires numerical methods as, e.g., finite elements, to obtain approximate solutions. By means of the classical sliding spaghetti problem, the present paper provides a guideline to the numerical modeling with conventional finite element codes. For this purpose, two approaches, one using solid elements and one using beam elements, respectively, are employed in the analysis, and the characteristics of each approach are addressed. The contact formulation realizing the interaction of the beam with its support demands particular attention in the context of sliding structures. Additionally, the paper employs the sliding-beam formulation as a third approach, which avoids the numerical difficulties caused by the large sliding motion through a suitable coordinate transformation. The present paper briefly outlines the theoretical fundamentals of the respective approaches for the modeling of sliding structures and gives a detailed comparison by means of the sliding spaghetti serving as a representative example. The specific advantages and limitations of the different approaches with regard to accuracy and computational efficiency are discussed in detail. Through the comparison, the sliding-beam formulation, which proves as an effective approach for the modeling, can be validated for the general problem of a sliding structure subjected to large deformation.

Health-related quality of life in Swedish pediatric burn patients and associations with burn and family characteristics.

PubMed

Sveen, J; Sjöberg, F; Öster, C

2014-08-01

Although many children with burns recover well and have a satisfying quality of life after the burn, some children do not adjust as well. Health-related quality of life (HRQoL) focuses on the impact health status has on quality of life. The aim of this study was to assess HRQoL with the American Burn Association/Shriners Hospitals for Children Burn Outcomes Questionnaire (BOQ) in a nationwide Swedish sample of children with burns 0.3-9.0 years after injury. Participants were parents (n=109) of children aged up to 18 years at the time of investigation who were treated at the Linköping or Uppsala Burn Center between 2000 and 2008. The majority of children did not have limitations in physical function and they did not seem to experience much pain. However, there were indications of psychosocial problems. Parents of preschool children reported most problems with the children's behavior and family disruption, whereas parents of children aged 5-18 years reported most problems with appearance and emotional health. There were mainly burn-related variables associated with suboptimal HRQoL in children aged 5-18 years, while family-related variables did not contribute as much. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

High voltage plasma sheath analysis related to TSS-1

NASA Technical Reports Server (NTRS)

Sheldon, John W.

1990-01-01

On the first mission of the Tethered Satellite System (TSS-1), a 1.8 m diameter spherical satellite will be deployed a distance of 20 km above the Space Shuttle Orbiter on an insulated conducting tether. The satellite will be held at electric potentials up to 5000 volts positive with respect to the ambient plasma. Due to the passage of the conducting tether through the Earth's magnetic field, an electromagnetic field (EMF) will be created, driving electrons down the tether to the Orbiter, out through an electron gun into the ionosphere and back into the positive-biased satellite. The main problem addressed here is the current-voltage characteristics of the ionospheric interaction with the satellite. The first problem is that while the satellite will be capable of measuring charged particle flow to the surface at several locations, the detectors have a limited range of acceptance angle. The second problem is that the angle of incidence of the incoming electrons will have to be relative to the local normal. This will be important in order to predict the magnitude of the detectable current at each detector location so the detector gain can be pre-set to the correct range. The plasma sheath was analyzed mathematically, and subroutines were written to solve relevant finite element, Taylor-Vlasov, and Poisson equations.

Mechanical design problems associated with turbopump fluid film bearings

NASA Technical Reports Server (NTRS)

Evces, Charles R.

1990-01-01

Most high speed cryogenic turbopumps for liquid propulsion rocket engines currently use ball or roller contact bearings for rotor support. The operating speeds, loads, clearances, and environments of these pumps combine to make bearing wear a limiting factor on turbopump life. An example is the high pressure oxygen turbopump (HPOTP) used in the Space Shuttle Main Engine (SSME). Although the HPOTP design life is 27,000 seconds at 30,000 rpms, or approximately 50 missions, bearings must currently be replaced after 2 missions. One solution to the bearing wear problem in the HPOTP, as well as in future turbopump designs, is the utilization of fluid film bearings in lieu of continuous contact bearings. Hydrostatic, hydrodynamic, and damping seal bearings are all replacement candidates for contact bearings in rocket engine high speed turbomachinery. These three types of fluid film bearings have different operating characteristics, but they share a common set of mechanical design opportunities and difficulties. Results of research to define some of the mechanical design issues are given. Problems considered include transient strat/stop rub, non-operational rotor support, bearing wear inspection and measurement, and bearing fluid supply route. Emphasis is given to the HPOTP preburner pump (PBP) bearing, but the results are pertinent to high-speed cryogenic turbomachinery in general.

Clinical predictors of gaming abstinence in help-seeking adult problematic gamers.

PubMed

King, Daniel L; Adair, Cam; Saunders, John B; Delfabbro, Paul H

2018-03-01

Research into the effectiveness of interventions for problematic gaming has been limited by a lack of data concerning the clinical characteristics of voluntary treatment-seekers; the nature and history of their gaming problems; and, their reasons for seeking help. The study aimed to identify variables predictive of short-term commitment to gaming abstinence following initial voluntary contact with an online help service. A total of 186 adult gamers with gaming-related problems were recruited online. Participants completed the DSM-5 Internet gaming disorder (IGD) checklist, Depression Anxiety Stress Scales-21, Internet Gaming Cognition Scale, Gaming Craving Scale, and Gaming Quality of Life Scale. A one-week follow up survey assessed adherence with intended gaming abstinence. Abstainers were less likely to have withdrawal symptoms and less likely to play action shooting games. Participants with mood symptoms (40% of the total) reported significantly more IGD symptoms, stronger maladaptive gaming cognitions (e.g., overvaluing game rewards), more previous occurrences of gaming problems, and poorer quality of life. However, mood symptoms did not predict abstinence from or continuation of gaming. Adults with gaming disorder seeking help to reduce their gaming may benefit initially from strategies that manage withdrawal and psychoeducation about riskier gaming activities. Copyright © 2018 Elsevier B.V. All rights reserved.

Nanomaterials in consumer's goods: the problems of risk assessment

NASA Astrophysics Data System (ADS)

Gmoshinski, I. V.; Khotimchenko, S. A.

2015-11-01

Nanotechnology and engineered nanomaterials are currently used in wide variety of cosmetic products, while their use in food industry, packaging materials, household chemicals etc. still includes a limited number of items and does not show a significant upward trend. However, the problem of priority nanomaterials associated risks is relevant due to their high production volumes and an constantly growing burden on the environment and population. In accordance with the frequency of use in mass-produced consumer goods, leading priority nanomaterials are silver nanoparticles (NPs) and (by a wide margin) NPs of gold, platinum, and titanium dioxide. Frequency of nanosized silica introduction into food products as a food additive, at the moment, seems to be underestimated, since the use of this nanomaterial is not declared by manufacturers of products and objective control of its content is difficult. Analysis of literature data on toxicological properties of nanomaterials shows that currently accumulated amount of information is sufficient to establish the safe doses of nanosized silver, gold and titanium dioxide. Data have been provided in a series of studies concerning the effect of oral intake of nanosized silica on the condition of laboratory animals, including on the performance of the immune system. The article examines the existing approaches to the assessment of population exposure to priority nanomaterials, characteristics of existing problems and risk management.

Ballistic projectile trajectory determining system

DOEpatents

Karr, Thomas J.

1997-01-01

A computer controlled system determines the three-dimensional trajectory of a ballistic projectile. To initialize the system, predictions of state parameters for a ballistic projectile are received at an estimator. The estimator uses the predictions of the state parameters to estimate first trajectory characteristics of the ballistic projectile. A single stationary monocular sensor then observes the actual first trajectory characteristics of the ballistic projectile. A comparator generates an error value related to the predicted state parameters by comparing the estimated first trajectory characteristics of the ballistic projectile with the observed first trajectory characteristics of the ballistic projectile. If the error value is equal to or greater than a selected limit, the predictions of the state parameters are adjusted. New estimates for the trajectory characteristics of the ballistic projectile are made and are then compared with actual observed trajectory characteristics. This process is repeated until the error value is less than the selected limit. Once the error value is less than the selected limit, a calculator calculates trajectory characteristics such a the origin and destination of the ballistic projectile.

The impact of childhood symptoms of conduct disorder on driver aggression in adulthood.

PubMed

Wickens, Christine M; Vingilis, Evelyn; Mann, Robert E; Erickson, Patricia; Toplak, Maggie E; Kolla, Nathan J; Seeley, Jane; Ialomiteanu, Anca R; Stoduto, Gina; Ilie, Gabriela

2015-05-01

Despite limited empirical investigation, existing scientific literature suggests that individuals with a history or current diagnosis of conduct disorder (CD) may be more likely to demonstrate reckless and aggressive driving. Much of the limited research in this field examines the impact of childhood CD on driver behaviour and collision risk in young adults. Few if any, studies assess the impact of this disorder on driver behaviour beyond age 21 years. The current research is a population-based study of the impact of CD symptoms during childhood on the risk of engaging in driver aggression during adulthood. Data are based on telephone interviews with 5230 respondents who reported having driven in the past year. Data are derived from the 2011-2013 cycles of the CAMH Monitor, an ongoing cross-sectional survey of adults in Ontario, Canada aged 18 years and older. A binary logistic regression analysis of self-reported driver aggression in the previous 12 months was conducted, consisting of measures of demographic characteristics, driving exposure, problem substance use, alcohol- and drug-impaired driving, symptoms of attention deficit hyperactivity disorder, and childhood (before age 15) symptoms of CD. When entered with demographic characteristics, driving exposure, and other potential confounders, childhood symptoms of CD increased the odds of reporting driver aggression more than two-fold (adjusted OR=2.12). Exploratory analyses of the interaction between childhood symptoms of CD and age was not a significant predictor of driver aggression. Results suggest that symptoms of CD during childhood are associated with significantly increased odds of self-reported driver aggression during adulthood. Limitations and future directions of the research are discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Screening accuracy of the parent-completed Ages and Stages Questionnaires - second edition as a broadband screener for motor problems in preschoolers with autism spectrum disorders.

PubMed

Vanvuchelen, Marleen; Van Schuerbeeck, Lise; Braeken, Marijke Aka

2017-01-01

Children with autism spectrum disorders are at risk for motor problems. However, this area is often overlooked in the developmental evaluation in autism diagnostic clinics. An alternative can be to identify children who should receive intensive motor assessment by using a parent-based screener. The aim of this study was to examine whether the Ages and Stages Questionnaires - second edition may be used to identify gross and fine motor problems in children. High-functioning children with autism spectrum disorder (n = 43, 22-54 m) participated in this study. Sensitivity, specificity, predictive values and areas under the receiver operating characteristic curve were calculated by comparing the Ages and Stages Questionnaires - second edition scores to the developmental evaluation of the Peabody Developmental Motor Scale - second edition. The results revealed that both the Ages and Stages Questionnaires - second edition gross and fine motor domain may be used to identify children without motor problems. In contrast, sensitivity analyses revealed the likelihood of under screening motor problems in this population. The Ages and Stages Questionnaires - second edition met only the criteria of a fair to good accuracy to identify poor gross motor (sensitivity = 100%) and below-average fine motor development (sensitivity = 71%) in this sample. Hence, the capacity of the Ages and Stages Questionnaires - second edition to identify motor problems in preschoolers with autism spectrum disorder appears to be limited. It is recommended to include a formal standardized motor test in the diagnostic procedure for all children with autism spectrum disorder. © The Author(s) 2016.

Patterns of dignity-related distress at the end of life: a cross-sectional study of patients with advanced cancer and care home residents.

PubMed

Hall, Sue; Davies, Joanna M; Gao, Wei; Higginson, Irene J

2014-10-01

To provide effective palliative care in different settings, it is important to understand and identify the sources of dignity-related distress experienced by people nearing the end of life. To describe and compare the sources of dignity-related distress reported by cancer patients and care home residents. Secondary analysis of merged data. Participants completed the Patient Dignity Inventory (assessing 25 sources of dignity-related distress) and measures of quality of life and depression. A total of 45 adult patients with advanced cancer referred to hospital-based palliative care teams in London, United Kingdom, and 60 residents living in one of 15 care homes in London. Care home residents were older and had poorer functioning. Both groups reported a wide range of dignity-related problems. Although the number or problems reported on the Patient Dignity Inventory was similar for the two groups (mean (standard deviation): 5.9 (5.5) for cancer patients and 4.1 (4.3) for care home residents, p = 0.07), there was a tendency for more cancer patients to report some existential problems. Experiencing physically distressing symptoms and functional limitations were prevalent problems for both groups. Patient Dignity Inventory problems were associated with poorer performance status and functioning for residents, with age and cognitive impairment for cancer patients and with poorer quality of life and depression for both groups. Although characteristics of the samples differed, similarities in the dignity-related problems reported by cancer patients and care home residents support research suggesting a common pathway towards death for malignant and non-malignant disease. A wider understanding of the sources of dignity-related distress would help clinicians provide more effective end-of-life care. © The Author(s) 2014.

Psychological factors, sociodemographic characteristics, and coping mechanisms associated with the self-stigma of problem gambling.

PubMed

Hing, Nerilee; Russell, Alex M T

2017-09-01

Background and aims Few studies have examined the stigma of problem gambling and little is known about those who internalize this prejudice as damaging self-stigma. This paper aimed to identify psychological factors, sociodemographic characteristics, and coping mechanisms associated with the self-stigma of problem gambling. Methods An online survey was conducted on 177 Australian adults with a current gambling problem to measure self-stigma, self-esteem, social anxiety, self-consciousness, psychological distress, symptom severity, most problematic gambling form, stigma coping mechanisms, and sociodemographic characteristics. Results All variables significantly correlated with self-stigma were considered for inclusion in a regression model. A multivariate linear regression indicated that higher levels of self-stigma were associated with: being female, being older, lower self-esteem, higher problem gambling severity score, and greater use of secrecy (standardized coefficients: 0.16, 0.14, -0.33, 0.23, and 0.15, respectively). Strongest predictors in the model were self-esteem, followed by symptom severity score. Together, predictors in the model accounted for 38.9% of the variance in self-stigma. Discussion and conclusions These results suggest that the self-stigma of problem gambling may be driven by similar mechanisms as the self-stigma of other mental health disorders, and impact similarly on self-esteem and coping. Thus, self-stigma reduction initiatives used for other mental health conditions may be effective for problem gambling. In contrast, however, the self-stigma of problem gambling increased with female gender and older age, which are associated with gaming machine problems. This group should, therefore, be a target population for efforts to reduce or better cope with the self-stigma of problem gambling.

Psychological factors, sociodemographic characteristics, and coping mechanisms associated with the self-stigma of problem gambling

PubMed Central

Hing, Nerilee; Russell, Alex M. T.

2017-01-01

Background and aims Few studies have examined the stigma of problem gambling and little is known about those who internalize this prejudice as damaging self-stigma. This paper aimed to identify psychological factors, sociodemographic characteristics, and coping mechanisms associated with the self-stigma of problem gambling. Methods An online survey was conducted on 177 Australian adults with a current gambling problem to measure self-stigma, self-esteem, social anxiety, self-consciousness, psychological distress, symptom severity, most problematic gambling form, stigma coping mechanisms, and sociodemographic characteristics. Results All variables significantly correlated with self-stigma were considered for inclusion in a regression model. A multivariate linear regression indicated that higher levels of self-stigma were associated with: being female, being older, lower self-esteem, higher problem gambling severity score, and greater use of secrecy (standardized coefficients: 0.16, 0.14, −0.33, 0.23, and 0.15, respectively). Strongest predictors in the model were self-esteem, followed by symptom severity score. Together, predictors in the model accounted for 38.9% of the variance in self-stigma. Discussion and conclusions These results suggest that the self-stigma of problem gambling may be driven by similar mechanisms as the self-stigma of other mental health disorders, and impact similarly on self-esteem and coping. Thus, self-stigma reduction initiatives used for other mental health conditions may be effective for problem gambling. In contrast, however, the self-stigma of problem gambling increased with female gender and older age, which are associated with gaming machine problems. This group should, therefore, be a target population for efforts to reduce or better cope with the self-stigma of problem gambling. PMID:28849669

Activity-Limiting Musculoskeletal Conditions in US Veterans Compared to Non-Veterans: Results from the 2013 National Health Interview Survey

PubMed Central

Hinojosa, Ramon

2016-01-01

Past military service is associated with health outcomes, both positive and negative. In this study we use the 2013 National Health Interview Survey to examine the constellation of conditions referred to as musculoskeletal disorders (MSDs) for Veterans and non-veterans with health conditions that limit their daily activities. Multivariate logistic regression analysis reveal that Veterans are more likely to report MSDs like neck and back problems, fracture bone and joint problems as an activity limiting problem compared to non-veterans. The relationship between age and reports of activity limiting MSDs is moderated by Veteran status. Veterans in this sample report more activity limiting MSDs at younger ages compared to non-veterans and fewer MSDs at older ages. This research contributes to our understanding of potentially limiting health conditions at earlier ages for Veterans. PMID:28005905

Trends in parent-reported emotional and behavioral problems among children using special education services.

PubMed

Pastor, Patricia N; Reuben, Cynthia A

2015-06-01

This report describes trends in health conditions reported by parents as the limitations leading to special education services for their children. Data are reported for children ages 6-17 (N=182,998) surveyed in households in the 2001-2012 National Health Interview Survey. Between 2001 and 2012, the overall percentage of U.S. children ages 6-17 who were receiving special education services increased from 7.2% to 8.7%. Between 2001 and 2012, the leading causes of activity limitations among children receiving special education services included emotional or behavioral problems, which increased from 36% to 43%; speech problems, which increased from 16% to 22%; and learning disability, which decreased from 41% to 27%. There were no significant trends in any of the other conditions considered as possible sources of activity limitations. Emotional and behavioral problems have become the most frequently reported source of activity limitations among children receiving special education services.

On Shaft Data Acquisition System (OSDAS)

NASA Technical Reports Server (NTRS)

Pedings, Marc; DeHart, Shawn; Formby, Jason; Naumann, Charles

2012-01-01

On Shaft Data Acquisition System (OSDAS) is a rugged, compact, multiple-channel data acquisition computer system that is designed to record data from instrumentation while operating under extreme rotational centrifugal or gravitational acceleration forces. This system, which was developed for the Heritage Fuel Air Turbine Test (HFATT) program, addresses the problem of recording multiple channels of high-sample-rate data on most any rotating test article by mounting the entire acquisition computer onboard with the turbine test article. With the limited availability of slip ring wires for power and communication, OSDAS utilizes its own resources to provide independent power and amplification for each instrument. Since OSDAS utilizes standard PC technology as well as shared code interfaces with the next-generation, real-time health monitoring system (SPARTAA Scalable Parallel Architecture for Real Time Analysis and Acquisition), this system could be expanded beyond its current capabilities, such as providing advanced health monitoring capabilities for the test article. High-conductor-count slip rings are expensive to purchase and maintain, yet only provide a limited number of conductors for routing instrumentation off the article and to a stationary data acquisition system. In addition to being limited to a small number of instruments, slip rings are prone to wear quickly, and introduce noise and other undesirable characteristics to the signal data. This led to the development of a system capable of recording high-density instrumentation, at high sample rates, on the test article itself, all while under extreme rotational stress. OSDAS is a fully functional PC-based system with 48 channels of 24-bit, high-sample-rate input channels, phase synchronized, with an onboard storage capacity of over 1/2-terabyte of solid-state storage. This recording system takes a novel approach to the problem of recording multiple channels of instrumentation, integrated with the test article itself, packaged in a compact/rugged form factor, consuming limited power, all while rotating at high turbine speeds.

Association Between Caregiver Stress and Behavioral Problems in the Children of Incarcerated Fathers in Hong Kong.

PubMed

Chui, Wing Hong

2016-10-01

Objectives Caregivers of children with incarcerated parents have received little attention in the literature, though they face unique incarceration-related challenges. General caregiver research has highlighted associations between caregiver distress and children's behavioral problems, even implying that the depressive tendencies of caregivers can be 'transmitted'. The current study investigated the applicability of this notion to caregivers responsible for children of incarcerated fathers. Methods Fifty-four female caregivers of children with incarcerated parents were recruited via collaboration with a non-governmental organization. Their levels of stress and depression were measured using questionnaires, as were the behavioral problems of children under their care. The relationships between the variables were examined. Results The results firstly suggest that these caregivers are vulnerable to psychological distress, with around 57 % of them suffering from borderline to severe depression. Obtained socio-demographic characteristics were not found to have any bearing on the psychosocial functioning of caregivers or children-rather, all psychosocial variables were interlinked, and further analyses revealed that the depression of caregivers mediated the relationship between their perceived stress and internalizing/externalizing behavioral problems of the child (β = .628 and β = .468 respectively), implicating depression as a mechanism via which adversity can be transferred from a caregiver to a child. Conclusions Increasing the focus on a caregiver's mental health may be an efficacious strategy in research and practice, perhaps by providing more support for caregivers and implementing joint caregiver-child interventions to more holistically alleviate problems in families affected by parental incarceration. Limitations of the current study and further recommendations are also discussed.

Caregiving-Related Sleep Problems and Their Relationship to Mental Health and Daytime Function in Female Veterans.

PubMed

Song, Yeonsu; Washington, Donna L; Yano, Elizabeth M; McCurry, Susan M; Fung, Constance H; Dzierzewski, Joseph M; Rodriguez, Juan Carlos; Jouldjian, Stella; Mitchell, Michael N; Alessi, Cathy A; Martin, Jennifer L

2018-01-01

To identify caregiving-related sleep problems and their relationship to mental health and daytime function in female Veterans. Female Veterans (N = 1,477) from cross-sectional, nationwide, postal survey data. The survey respondent characteristics included demographics, comorbidity, physical activity, health, use of sleep medications, and history of sleep apnea. They self-identified caregiving- related sleep problems (i.e., those who had trouble sleeping because of caring for a sick adult, an infant/child, or other respondents). Patient Health Questionnaire (PHQ-4) was used to assess mental health, and daytime function was measured using 11 items of International Classification of Sleep Disorders-2 (ICSD-2). Female Veterans with self-identified sleep problems due to caring for a sick adult (n = 59) experienced significantly more symptoms of depression and anxiety (p < 0.001) and impairment in daytime function (e.g., fatigue, daytime sleepiness, loss of concentration, p < 0.001) than those with self-identified sleep problems due to caring for an infant or child (n = 95) or all other respondents (n = 1,323) after controlling for the respondent characteristics. Healthcare providers should pay attention to assessing sleep characteristics of female Veterans with caregiving responsibilities, particularly those caregiving for a sick adult.

Students’ errors in solving combinatorics problems observed from the characteristics of RME modeling

NASA Astrophysics Data System (ADS)

Meika, I.; Suryadi, D.; Darhim

2018-01-01

This article was written based on the learning evaluation results of students’ errors in solving combinatorics problems observed from the characteristics of Realistic Mathematics Education (RME); that is modeling. Descriptive method was employed by involving 55 students from two international-based pilot state senior high schools in Banten. The findings of the study suggested that the students still committed errors in simplifying the problem as much 46%; errors in making mathematical model (horizontal mathematization) as much 60%; errors in finishing mathematical model (vertical mathematization) as much 65%; and errors in interpretation as well as validation as much 66%.

NASA Conference on Thermal Radiation Problems in Space Technology: a Compilation of Summaries of the Papers Presented

NASA Technical Reports Server (NTRS)

1960-01-01

This document contains summaries of the talks presented at a small NASA Conference on Thermal Radiation Problems in Space Technology held at the Langley Research Center on September 12 and 13, 1960. The conferees were NASA members and NASA contractors directly concerned with radiation characteristics of materials and with thermal problems of spacecraft. The purpose of the conference was not only to present significant research information but also to provide an opportunity for the conferees to become aware of each other's fields of interest, activities, techniques, and problems. As arranged herein, the first set of talks, mostly by the contractors, is concerned with surfaces and surface coatings, and with the determination of their pertinent characteristics. The second set of talks, mostly by NASA personnel, is concerned with spacecraft and their thermal problems.

"Live Chat" Clients at Kids Help Phone: Individual Characteristics and Problem Topics.

PubMed

Haner, Dilys; Pepler, Debra

2016-01-01

Young people in Canada prefer to use the Internet over face-to-face contact when seeking help for problems of daily living and mental health problems. Kids Help Phone (KHP) provides on-demand, anonymous help to young people via telephone and Live Chat technologies. Two hundred thirty-two phone clients and 230 Live Chat clients responded to a questionnaire at this otherwise anonymous service, providing previously inaccessible data about their individual characteristics and characterizations of the problems for which they sought help. There was a larger proportion of weighty problems (mental health and suicide) among chatters than callers. There were also more non-heterosexual youth, and those who identified as Asian and Black African or Caribbean, using Live Chat than phone. Implications for training Live Chat counsellors to respond effectively to chatters are discussed.

Space Shuttle Plume and Plume Impingement Study

NASA Technical Reports Server (NTRS)

Tevepaugh, J. A.; Penny, M. M.

1977-01-01

The extent of the influence of the propulsion system exhaust plumes on the vehicle performance and control characteristics is a complex function of vehicle geometry, propulsion system geometry, engine operating conditions and vehicle flight trajectory were investigated. Analytical support of the plume technology test program was directed at the two latter problem areas: (1) definition of the full-scale exhaust plume characteristics, (2) application of appropriate similarity parameters; and (3) analysis of wind tunnel test data. Verification of the two-phase plume and plume impingement models was directed toward the definition of the full-scale exhaust plume characteristics and the separation motor impingement problem.

Multidimensional Predictors of Treatment Outcome in Usual Care for Adolescent Conduct Problems and Substance Use

PubMed Central

Hogue, Aaron; Henderson, Craig E.; Schmidt, Adam T.

2016-01-01

This study investigated baseline client characteristics that predicted long-term treatment outcomes among adolescents referred from school and community sources and enrolled in usual care for conduct and substance use problems. Predictor effects for multiple demographic (age, sex, race/ethnicity), clinical (baseline symptom severity, comorbidity, family discord), and developmental psychopathology (behavioral dysregulation, depression, peer delinquency) characteristics were examined. Participants were 205 adolescents (52% male; mean age 15.7 years) from diverse backgrounds (59% Hispanic American, 21% African American, 15% multiracial, 6% other) residing in a large inner-city area. As expected, characteristics from all three predictor categories were related to various aspects of change in externalizing problems, delinquent acts, and substance use at one-year follow-up. The strongest predictive effect was found for baseline symptom severity: Youth with greater severity showed greater clinical gains. Higher levels of co-occurring developmental psychopathology characteristics likewise predicted better outcomes. Exploratory analyses showed that change over time in developmental psychopathology characteristics (peer delinquency, depression) was related to change in delinquent acts and substance use. Implications for serving multiproblem adolescents and tailoring treatment plans in routine care are discussed. PMID:26884380

Physical characteristics related to bra fit.

PubMed

Chen, Chin-Man; LaBat, Karen; Bye, Elizabeth

2010-04-01

Producing well-fitting garments has been a challenge for retailers and manufacturers since mass production began. Poorly fitted bras can cause discomfort or pain and result in lost sales for retailers. Because body contours are important factors affecting bra fit, this study analyses the relationship of physical characteristics to bra-fit problems. This study has used 3-D body-scanning technology to extract upper body angles from a sample of 103 college women; these data were used to categorise physical characteristics into shoulder slope, bust prominence, back curvature and acromion placement. Relationships between these physical categories and bra-fit problems were then analysed. Results show that significant main effects and two-way interactions of the physical categories exist in the fit problems of poor bra support and bra-motion restriction. The findings are valuable in helping the apparel industry create better-fitting bras. STATEMENT OF RELEVANCE: Poorly fitted bras can cause discomfort or pain and result in lost sales for retailers. The findings regarding body-shape classification provide researchers with a statistics method to quantify physical characteristics and the findings regarding the relationship analysis between physical characteristics and bra fit offer bra companies valuable information about bra-fit perceptions attributable to women with figure variations.

Features and Characteristics of Problem Based Learning

ERIC Educational Resources Information Center

Ceker, Eser; Ozdamli, Fezile

2016-01-01

Throughout the years, there appears to be an increase in Problem Based Learning applications in education; and Problem Based Learning related research areas. The main aim of this research is to underline the fundamentals (basic elements) of Problem Based Learning, investigate the dimensions of research approached to PBL oriented areas (with a look…

Pre-Adoption Adversity, Maternal Stress, and Behavior Problems at School-Age in International Adoptees

ERIC Educational Resources Information Center

Gagnon-Oosterwaal, Noemi; Cossette, Louise; Smolla, Nicole; Pomerleau, Andree; Malcuit, Gerard; Chicoine, Jean-Francois; Belhumeur, Celine; Jeliu, Gloria; Begin, Jean; Seguin, Renee

2012-01-01

Internationally adopted children present more behavior problems than non-adopted children and are overrepresented in mental health services. These problems are related to children's pre-adoption environment, but adoptive families' functioning and characteristics may also affect the development of behavior problems in adopted children. The aim of…

Human Performance on the Traveling Salesman and Related Problems: A Review

ERIC Educational Resources Information Center

MacGregor, James N.; Chu, Yun

2011-01-01

The article provides a review of recent research on human performance on the traveling salesman problem (TSP) and related combinatorial optimization problems. We discuss what combinatorial optimization problems are, why they are important, and why they may be of interest to cognitive scientists. We next describe the main characteristics of human…

Assessing streamflow characteristics as limiting factors on benthic invertebrate assemblages in streams across the western United States

USGS Publications Warehouse

Konrad, C.P.; Brasher, A.M.D.; May, J.T.

2008-01-01

4. Relative abundance of Plecoptera, richness of non-insect taxa and relative abundance of intolerant taxa were associated with multiple streamflow metrics. Metrics of sensitive taxa (Ephemeroptera, Plecoptera and Trichoptera), and intolerant taxa generally had ceilings associated with flow metrics while metrics of tolerant taxa, non-insects, dominance and chironomids generally had floors. Broader characteristics of invertebrate assemblages such as abundance and richness had fewer limits, but these limits were nonetheless associated with a broad range of streamflow characteristics.

A Children of Twins Study of parental divorce and offspring psychopathology

PubMed Central

D'Onofrio, Brian M.; Turkheimer, Eric; Emery, Robert E.; Maes, Hermine H.; Silberg, Judy; Eaves, Lindon J.

2010-01-01

Background Although parental divorce is associated with increased substance use and internalizing problems, experiencing the separation of one's parents may not cause these outcomes. The relations may be due to genetic or environmental selection factors, characteristics that lead to both marital separation and offspring functioning. Method We used the Children of Twins (CoT) Design to explore whether unmeasured genetic or environmental factors related to the twin parent, and measured characteristics of both parents, account for the association between parental divorce and offspring substance use and internalizing problems. Results The association between parental divorce and offspring substance use problems remained robust when controlling for genetic and environmental risk from the twin parent associated with parental divorce, and measured characteristics of both parents. The results do not prove, but are consistent with, a causal connection. In contrast, the analyses suggest that shared genetic liability in parents and their offspring accounts for the increased risk of internalizing problems in adult offspring from divorced families. Conclusions The study illustrates that unmeasured genetic and environmental selection factors must be considered when studying parental divorce. In explaining associations between parental divorce and young-adult adjustment, our evidence suggests that selection versus causal mechanisms may operate differently for substance abuse (a causal relation) and internalizing problems (an artifact of selection). The CoT design only controls for the genetic and environmental characteristics of one parent; thus, additional genetically informed analyses are needed. PMID:17593147

Hierarchical Ensemble Methods for Protein Function Prediction

PubMed Central

2014-01-01

Protein function prediction is a complex multiclass multilabel classification problem, characterized by multiple issues such as the incompleteness of the available annotations, the integration of multiple sources of high dimensional biomolecular data, the unbalance of several functional classes, and the difficulty of univocally determining negative examples. Moreover, the hierarchical relationships between functional classes that characterize both the Gene Ontology and FunCat taxonomies motivate the development of hierarchy-aware prediction methods that showed significantly better performances than hierarchical-unaware “flat” prediction methods. In this paper, we provide a comprehensive review of hierarchical methods for protein function prediction based on ensembles of learning machines. According to this general approach, a separate learning machine is trained to learn a specific functional term and then the resulting predictions are assembled in a “consensus” ensemble decision, taking into account the hierarchical relationships between classes. The main hierarchical ensemble methods proposed in the literature are discussed in the context of existing computational methods for protein function prediction, highlighting their characteristics, advantages, and limitations. Open problems of this exciting research area of computational biology are finally considered, outlining novel perspectives for future research. PMID:25937954