Cognitive development in introductory physics: A research-based approach to curriculum reform

NASA Astrophysics Data System (ADS)

Teodorescu, Raluca Elena

This project describes the research on a classification of physics problems in the context of introductory physics courses. This classification, called the Taxonomy of Introductory Physics Problems (TIPP), relates physics problems to the cognitive processes required to solve them. TIPP was created for designing and clarifying educational objectives, for developing assessments that can evaluate individual component processes of the problem-solving process, and for guiding curriculum design in introductory physics courses, specifically within the context of a "thinking-skills" curriculum. TIPP relies on the following resources: (1) cognitive research findings adopted by physics education research, (2) expert-novice research discoveries acknowledged by physics education research, (3) an educational psychology taxonomy for educational objectives, and (4) various collections of physics problems created by physics education researchers or developed by textbook authors. TIPP was used in the years 2006--2008 to reform the first semester of the introductory algebra-based physics course (called Phys 11) at The George Washington University. The reform sought to transform our curriculum into a "thinking-skills" curriculum that trades "breadth for depth" by focusing on fewer topics while targeting the students' cognitive development. We employed existing research on the physics problem-solving expert-novice behavior, cognitive science and behavioral science findings, and educational psychology recommendations. Our pedagogy relies on didactic constructs such as the GW-ACCESS problem-solving protocol, learning progressions and concept maps that we have developed and implemented in our introductory physics course. These tools were designed based on TIPP. Their purpose is: (1) to help students build local and global coherent knowledge structures, (2) to develop more context-independent problem-solving abilities, (3) to gain confidence in problem solving, and (4) to establish connections between everyday phenomena and underlying physics concepts. We organize traditional and research-based physics problems such that students experience a gradual increase in complexity related to problem context, problem features and cognitive processes needed to solve the problem. The instructional environment that we designed allows for explicit monitoring, control and measurement of the cognitive processes exercised during the instruction period. It is easily adaptable to any kind of curriculum and can be readily adjusted throughout the semester. To assess the development of students' problem-solving abilities, we created rubrics that measure specific aspects of the thinking involved in physics problem solving. The Colorado Learning Attitudes about Science Survey (CLASS) was administered pre- and post-instruction to determine students' shift in dispositions towards learning physics. The Force Concept Inventory (FCI) was administered pre- and post-instruction to determine students' level of conceptual understanding. The results feature improvements in students' problem-solving abilities and in their attitudes towards learning physics.

Construct Validation of the Physics Metacognition Inventory

ERIC Educational Resources Information Center

Taasoobshirazi, Gita; Farley, John

2013-01-01

The 24-item Physics Metacognition Inventory was developed to measure physics students' metacognition for problem solving. Items were classified into eight subcomponents subsumed under two broader components: knowledge of cognition and regulation of cognition. The students' scores on the inventory were found to be reliable and related to students'…

Examining issues of underrepresented minority students in introductory physics

NASA Astrophysics Data System (ADS)

Watkins, Jessica Ellen

In this dissertation we examine several issues related to the retention of under-represented minority students in physics and science. In the first section, we show that in calculus-based introductory physics courses, the gender gap on the FCI is diminished through the use of interactive techniques, but in lower-level introductory courses, the gap persists, similar to reports published at other institutions. We find that under-represented racial minorities perform similar to their peers with comparable academic preparation on conceptual surveys, but their average exam grades and course grades are lower. We also examine student persistence in science majors; finding a significant relationship between pedagogy in an introductory physics course and persistence in science. In the second section, we look at student end-of-semester evaluations and find that female students rate interactive teaching methods a full point lower than their male peers. Looking more deeply at student interview data, we find that female students report more social issues related to the discussions in class and both male and female students cite feeling pressure to obtain the correct answer to clicker questions. Finally, we take a look an often-cited claim for gender differences in STEM participation: cognitive differences explain achievement differences in physics. We examine specifically the role of mental rotations in physics achievement and problem-solving, viewing mental rotations as a tool that students can use on physics problems. We first look at student survey results for lower-level introductory students, finding a low, but significant correlation between performance on a mental rotations test and performance in introductory physics courses. In contrast, we did not find a significant relationship for students in the upper-level introductory course. We also examine student problem-solving interviews to investigate the role of mental rotations on introductory problems.

Video Analysis of a Plucked String: An Example of Problem-based Learning

NASA Astrophysics Data System (ADS)

Wentworth, Christopher D.; Buse, Eric

2009-11-01

Problem-based learning is a teaching methodology that grounds learning within the context of solving a real problem. Typically the problem initiates learning of concepts rather than simply being an application of the concept, and students take the lead in identifying what must be developed to solve the problem. Problem-based learning in upper-level physics courses can be challenging, because of the time and financial requirements necessary to generate real data. Here, we present a problem that motivates learning about partial differential equations and their solution in a mathematical methods for physics course. Students study a plucked elastic cord using high speed digital video. After creating video clips of the cord motion under different tensions they are asked to create a mathematical model. Ultimately, students develop and solve a model that includes damping effects that are clearly visible in the videos. The digital video files used in this project are available on the web at http://physics.doane.edu .

Problems experienced and envisioned for dynamical physical systems

NASA Technical Reports Server (NTRS)

Ryan, R. S.

1985-01-01

The use of high performance systems, which is the trend of future space systems, naturally leads to lower margins and a higher sensitivity to parameter variations and, therefore, more problems of dynamical physical systems. To circumvent dynamic problems of these systems, appropriate design, verification analysis, and tests must be planned and conducted. The basic design goal is to define the problem before it occurs. The primary approach for meeting this goal is a good understanding and reviewing of the problems experienced in the past in terms of the system under design. This paper reviews many of the dynamic problems experienced in space systems design and operation, categorizes them as to causes, and envisions future program implications, developing recommendations for analysis and test approaches.

Time use differences in activity participation among children 4-5 years old with and without the risk of developing conduct problems.

PubMed

Yu, Mong-Lin; Ziviani, Jenny; Baxter, Janeen; Haynes, Michele

2012-01-01

Conduct problems in childhood are associated with the way in which children engage in daily activities. Research, to date, on conduct problems in relation to time use has primarily focused on school aged children and their participation in discrete activities such as watching TV and sport. The purpose of the present study is to determine if children at risk of developing conduct problems have different activity patterns compared to those not at risk. Specifically aspects of time use which concern involvement in activities that provide physical exertion, structure, rest and social engagement were examined. Data for this investigation were drawn from the Longitudinal Study of Australian Children (Wave 1) and focused on 4936 children aged 4-5 years. Findings indicate that children at risk of developing conduct problems spend significantly more time in: physical activities such as "riding a bike", and "in the company of adults only" than children not at risk of developing conduct problems but less time "with peers under adult supervision". Gender differences were also found in the same activities with boys participating in more "bike riding" and activities "without peers under adult supervision" than girls. Young children generally participated in more physical activities and spend more time "with peers while supervised by adults" on weekend days, and more time in "structured activities" and "in the company of adults only" on weekdays. These findings are discussed in respect of the potentially risky nature of physical activity choice and the contribution of adult supervision in the context of peer group participation for children at risk of developing conduct problems. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effects of menstruation and contraceptive pill on the performance of physical education students.

PubMed Central

Bale, P.; Davies, J.

1983-01-01

Of the 109 specialist female physical education students who answered a detailed questionnaire on menstruation and the contraceptive pill in relation to exercise, 91 (83.5%) reported that they suffered menstrual problems. These included stomach ache, depression, abdominal cramps and backache. Over two-thirds of the students considered that these problems adversely influenced their physical performance. However, whether they had a mainly physiological or psychological effect is not clear. Many of the students with menstrual problems thought that exercise had a beneficial effect and helped alleviate their discomfort. A small number of students reported problems such as amenorrhoea and reduced menses possibly due to excessive training. Just under half the students in the investigation took the contraceptive pill, and though as many students taking the pill complained of menstrual problems as those not taking it, they reported less problems and to a lesser degree. Most students claimed that taking the contraceptive pill had no effect upon their performance. Images p46-a p46-b PMID:6850205

Practicing versus Inventing with Contrasting Cases: The Effects of Telling First on Learning and Transfer

ERIC Educational Resources Information Center

Schwartz, Daniel L.; Chase, Catherine C.; Oppezzo, Marily A.; Chin, Doris B.

2011-01-01

Being told procedures and concepts before problem solving can inadvertently undermine the learning of deep structures in physics. If students do not learn the underlying structure of physical phenomena, they will exhibit poor transfer. Two studies on teaching physics to adolescents compared the effects of "telling" students before and after…

Stueckelberg and Molecular Physics

NASA Astrophysics Data System (ADS)

Lacki, Jan

The first period of E. C. G. Stueckelberg's scientific career was marked by important contributions he made to molecular physics.1 After publishing his thesis in 1927 in Basel [1] Stueckelberg joined the prestigious Palmer Physical Laboratory in Princeton where he worked under the guidance of Karl Taylor Compton, brother of Arthur Holly Compton. Stueckelberg owed this position devoted several papers to problems of molecular physics. Stueckelberg had the benefit at Princeton of exchanges with other gifted members of the Palmer Physical Laboratory, Philip M. Morse and E. U. Condon among others.3 to a recommendation by A. Sommerfeld.2 In this stimulating environment, he devoted several papers to problems of molecular physics. Stueckelberg had the benefit at Princeton of exchanges with other gifted members of the Palmer Physical Laboratory, Philip M. Morse and E. U. Condon among others.3

Inhibitory Control, but Not Prolonged Object-Related Experience Appears to Affect Physical Problem-Solving Performance of Pet Dogs.

PubMed

Müller, Corsin A; Riemer, Stefanie; Virányi, Zsófia; Huber, Ludwig; Range, Friederike

2016-01-01

Human infants develop an understanding of their physical environment through playful interactions with objects. Similar processes may influence also the performance of non-human animals in physical problem-solving tasks, but to date there is little empirical data to evaluate this hypothesis. In addition or alternatively to prior experiences, inhibitory control has been suggested as a factor underlying the considerable individual differences in performance reported for many species. Here we report a study in which we manipulated the extent of object-related experience for a cohort of dogs (Canis familiaris) of the breed Border Collie over a period of 18 months, and assessed their level of inhibitory control, prior to testing them in a series of four physical problem-solving tasks. We found no evidence that differences in object-related experience explain variability in performance in these tasks. It thus appears that dogs do not transfer knowledge about physical rules from one physical problem-solving task to another, but rather approach each task as a novel problem. Our results, however, suggest that individual performance in these tasks is influenced in a complex way by the subject's level of inhibitory control. Depending on the task, inhibitory control had a positive or a negative effect on performance and different aspects of inhibitory control turned out to be the best predictors of individual performance in the different tasks. Therefore, studying the interplay between inhibitory control and problem-solving performance will make an important contribution to our understanding of individual and species differences in physical problem-solving performance.

Inhibitory Control, but Not Prolonged Object-Related Experience Appears to Affect Physical Problem-Solving Performance of Pet Dogs

PubMed Central

Müller, Corsin A.; Riemer, Stefanie; Virányi, Zsófia; Huber, Ludwig; Range, Friederike

2016-01-01

Human infants develop an understanding of their physical environment through playful interactions with objects. Similar processes may influence also the performance of non-human animals in physical problem-solving tasks, but to date there is little empirical data to evaluate this hypothesis. In addition or alternatively to prior experiences, inhibitory control has been suggested as a factor underlying the considerable individual differences in performance reported for many species. Here we report a study in which we manipulated the extent of object-related experience for a cohort of dogs (Canis familiaris) of the breed Border Collie over a period of 18 months, and assessed their level of inhibitory control, prior to testing them in a series of four physical problem-solving tasks. We found no evidence that differences in object-related experience explain variability in performance in these tasks. It thus appears that dogs do not transfer knowledge about physical rules from one physical problem-solving task to another, but rather approach each task as a novel problem. Our results, however, suggest that individual performance in these tasks is influenced in a complex way by the subject’s level of inhibitory control. Depending on the task, inhibitory control had a positive or a negative effect on performance and different aspects of inhibitory control turned out to be the best predictors of individual performance in the different tasks. Therefore, studying the interplay between inhibitory control and problem-solving performance will make an important contribution to our understanding of individual and species differences in physical problem-solving performance. PMID:26863141

What Physicist Mean By The Equals Sign In Undergraduate Education

NASA Astrophysics Data System (ADS)

Zohrabi Alaee, Dina; Kornick, Kellianne; Sayre, Eleanor C.; Franklin, Scott V.

2017-01-01

Mathematical concepts and tools have an important role in physics. Faculties want students to think critically about mathematics and the underlying fundamental concepts, rather than simply memorizing a series of equations and answers. The equals sign - ubiquitous in problem solving - carries different conceptual meaning depending on how it is used; this meaning is deeply tied to cultural practices in problem solving in physics. We use symbolic forms to investigate the conceptual and cultural meanings of the equals sign across physics contexts. We built and validated a rubric to classify the ways that physics students use the equals sign in their written work. Our categories are causality, assignments, definitional, balancing, and just math. We analyze students' use of the equals sign in their written homework and exam solutions in an upper-division electrostatics course. We correlate the kinds of equal signs within problem solutions with the difficulty of the problem. We compare they ways students use the equals sign to their course lectures and textbook.

After an Attempt: A Guide for Taking Care of Your Family Member After Treatment in the Emergency Department

MedlinePlus

... the person’s physical and mental health. Emergency department staff should look for underlying physical problems that may ... that can cause emotional distress. While emergency department staff prefer to assess people who are sober, they ...

Physics-Based Preconditioning of a Compressible Flow Solver for Large-Scale Simulations of Additive Manufacturing Processes

NASA Astrophysics Data System (ADS)

Weston, Brian; Nourgaliev, Robert; Delplanque, Jean-Pierre

2017-11-01

We present a new block-based Schur complement preconditioner for simulating all-speed compressible flow with phase change. The conservation equations are discretized with a reconstructed Discontinuous Galerkin method and integrated in time with fully implicit time discretization schemes. The resulting set of non-linear equations is converged using a robust Newton-Krylov framework. Due to the stiffness of the underlying physics associated with stiff acoustic waves and viscous material strength effects, we solve for the primitive-variables (pressure, velocity, and temperature). To enable convergence of the highly ill-conditioned linearized systems, we develop a physics-based preconditioner, utilizing approximate block factorization techniques to reduce the fully-coupled 3×3 system to a pair of reduced 2×2 systems. We demonstrate that our preconditioned Newton-Krylov framework converges on very stiff multi-physics problems, corresponding to large CFL and Fourier numbers, with excellent algorithmic and parallel scalability. Results are shown for the classic lid-driven cavity flow problem as well as for 3D laser-induced phase change. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Back to basics: informing the public of co-morbid physical health problems in those with mental illness.

PubMed

Ahire, Mrinalini; Sheridan, Judith; Regbetz, Shane; Stacey, Phillip; Scott, James G

2013-02-01

Those with mental illness are at increased risk of physical health problems. The current study aimed to examine the information available online to the Australian public about the increased risk and consequences of physical illness in those with mental health problems and the services available to address these co-morbidities. A structured online search was conducted with the search engine Google Australia (www.google.com.au) using generic search terms 'mental health information Australia', 'mental illness information Australia', 'depression', 'anxiety', and 'psychosis'. The direct content of websites was examined for information on the physical co-morbidities of mental illness. All external links on high-profile websites [the first five websites retrieved under each search term (n = 25)] were examined for information pertaining to physical health. Only 4.2% of websites informing the public about mental health contained direct content information about the increased risk of physical co-morbidities. The Australian Government's Department of Health and Ageing site did not contain any information. Of the high-profile websites, 62% had external links to resources about physical health and 55% had recommendations or resources for physical health. Most recommendations were generic. Relative to the seriousness of this problem, there is a paucity of information available to the public about the increased physical health risks associated with mental illness. Improved public awareness is the starting point of addressing this health inequity.

The NASTRAN demonstration program manual (level 16.0)

NASA Technical Reports Server (NTRS)

1976-01-01

The types of problems that can be solved with NASTRAN are presented. The nature of the problem, the underlying theory, the specific geometric and physical input quanties, and the comparison of theoretical and NASTRAN results are discussed. At least one problem for each of the rigid formats and nearly all of the elements or provided. The features of NASTRAN demonstrated by specific problems are described. The results obtained are valid.

Interface between Physics and Biology: Training a New Generation of Creative Bilingual Scientists.

PubMed

Riveline, Daniel; Kruse, Karsten

2017-08-01

Whereas physics seeks for universal laws underlying natural phenomena, biology accounts for complexity and specificity of molecular details. Contemporary biological physics requires people capable of working at this interface. New programs prepare scientists who transform respective disciplinary views into innovative approaches for solving outstanding problems in the life sciences. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluating physical and behavioral changes in older adults.

PubMed

Walton, J C; Miller, J M

1998-04-01

In older adults, subtle and sometime not so subtle physical or behavior changes can act as early warning signs of changing status. Nonspecific signs and symptoms occurring in older adults such as decline in previous functional capacity, urinary incontinence, anorexia, confusion, or unexplained falls may be signs of infection, medication interaction, dehydration, constipation, or sleep deprivation. Nurses, by critically assessing the situation early, may identify a developing problem. Prompt and early diagnosis of the underlying problem may save costly extended hospitalization or even prevent life-threatening complications.

A Localized Ensemble Kalman Smoother

NASA Technical Reports Server (NTRS)

Butala, Mark D.

2012-01-01

Numerous geophysical inverse problems prove difficult because the available measurements are indirectly related to the underlying unknown dynamic state and the physics governing the system may involve imperfect models or unobserved parameters. Data assimilation addresses these difficulties by combining the measurements and physical knowledge. The main challenge in such problems usually involves their high dimensionality and the standard statistical methods prove computationally intractable. This paper develops and addresses the theoretical convergence of a new high-dimensional Monte-Carlo approach called the localized ensemble Kalman smoother.

Mirror, Mirror, on the Wall.

ERIC Educational Resources Information Center

Flowers, Jim; Rose, M. Annette

1998-01-01

Students use tables of anthropometric data, their own measurements, underlying principles of physics, and math to solve a problem. The problem is to determine the height of a wall mirror, and where to mount it, so that 90% of the clientele can view their entire length without stretching or bending. (Author)

Underworld results as a triple (shopping list, posterior, priors)

NASA Astrophysics Data System (ADS)

Quenette, S. M.; Moresi, L. N.; Abramson, D.

2013-12-01

When studying long-term lithosphere deformation and other such large-scale, spatially distinct and behaviour rich problems, there is a natural trade-off between the meaning of a model, the observations used to validate the model and the ability to compute over this space. For example, many models of varying lithologies, rheological properties and underlying physics may reasonably match (or not match) observables. To compound this problem, each realisation is computationally intensive, requiring high resolution, algorithm tuning and code tuning to contemporary computer hardware. It is often intractable to use sampling based assimilation methods, but with better optimisation, the window of tractability becomes wider. The ultimate goal is to find a sweet-spot where a formal assimilation method is used, and where a model affines to observations. Its natural to think of this as an inverse problem, in which the underlying physics may be fixed and the rheological properties and possibly the lithologies themselves are unknown. What happens when we push this approach and treat some portion of the underlying physics as an unknown? At its extreme this is an intractable problem. However, there is an analogy here with how we develop software for these scientific problems. What happens when we treat the changing part of a largely complete code as an unknown, where the changes are working towards this sweet-spot? When posed as a Bayesian inverse problem the result is a triple - the model changes, the real priors and the real posterior. Not only does this give meaning to the process by which a code changes, it forms a mathematical bridge from an inverse problem to compiler optimisations given such changes. As a stepping stone example we show a regional scale heat flow model with constraining observations, and the inverse process including increasingly complexity in the software. The implementation uses Underworld-GT (Underworld plus research extras to import geology and export geothermic measures, etc). Underworld uses StGermain an early (partial) implementation of the theories described here.

Denaturation of collagen structures and their transformation under the physical and chemical effects

NASA Astrophysics Data System (ADS)

Ivankin, A.; Boldirev, V.; Fadeev, G.; Baburina, M.; Kulikovskii, A.; Vostrikova, N.

2017-11-01

The process of denaturation of collagen structures under the influence of physical and chemical factors play an important role in the manufacture of food technology and the production of drugs for medicine and cosmetology. The paper discussed the problem of the combined effects of heat treatment, mechanical dispersion and ultrasonic action on the structural changes of the animal collagen in the presence of weak protonated organic acids. Algorithm combined effects of physical and chemical factors as a result of the formation of the technological properties of products containing collagen has been shown.

The Effects of Parental Depressive Symptoms, Appraisals, and Physical Punishment on Later Child Externalizing Behavior

PubMed Central

Callender, Kevin A.; Olson, Sheryl L.; Choe, Daniel E.; Sameroff, Arnold J.

2014-01-01

Examined a cognitive-behavioral pathway by which depressive symptoms in mothers and fathers increase risk for later child externalizing problem behavior via parents’ appraisals of child behavior and physical discipline. Participants were 245 children (118 girls) at risk for school-age conduct problems, and their parents and teachers. Children were approximately 3 years old at Time 1 (T1) and 5 ½ years old at Time 2 (T2). At T1, mothers and fathers reported their depressive symptoms, perceptions of their child’s reciprocal affection and responsiveness, frequency of physical punishment, and child externalizing problems. Mothers, fathers, and teachers provided ratings of externalizing behavior at T2. Structural equation modeling revealed that parents’ negative attributions mediated positive relations between their depressive symptoms and frequency of physical punishment for both fathers and mothers. More frequent physical punishment, in turn, predicted increased child externalizing behavior at T2. In future research, transactional mechanisms underlying effects of clinical depression on child conduct problems should be explored at multiple stages of development. For parents showing depressive symptoms, restructuring distorted perceptions about their children’s behavior may be an important component of intervention programs. PMID:21947616

The effects of parental depressive symptoms, appraisals, and physical punishment on later child externalizing behavior.

PubMed

Callender, Kevin A; Olson, Sheryl L; Choe, Daniel E; Sameroff, Arnold J

2012-04-01

Examined a cognitive-behavioral pathway by which depressive symptoms in mothers and fathers increase risk for later child externalizing problem behavior via parents' appraisals of child behavior and physical discipline. Participants were 245 children (118 girls) at risk for school-age conduct problems, and their parents and teachers. Children were approximately 3 years old at Time 1 (T1) and 5 ½ years old at Time 2 (T2). At T1, mothers and fathers reported their depressive symptoms, perceptions of their child's reciprocal affection and responsiveness, frequency of physical punishment, and child externalizing problems. Mothers, fathers, and teachers provided ratings of externalizing behavior at T2. Structural equation modeling revealed that parents' negative attributions mediated positive relations between their depressive symptoms and frequency of physical punishment for both fathers and mothers. More frequent physical punishment, in turn, predicted increased child externalizing behavior at T2. In future research, transactional mechanisms underlying effects of clinical depression on child conduct problems should be explored at multiple stages of development. For parents showing depressive symptoms, restructuring distorted perceptions about their children's behavior may be an important component of intervention programs.

Model-Based Detection of Radioactive Contraband for Harbor Defense Incorporating Compton Scattering Physics

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

Candy, J V; Chambers, D H; Breitfeller, E F

2010-03-02

The detection of radioactive contraband is a critical problem is maintaining national security for any country. Photon emissions from threat materials challenge both detection and measurement technologies especially when concealed by various types of shielding complicating the transport physics significantly. This problem becomes especially important when ships are intercepted by U.S. Coast Guard harbor patrols searching for contraband. The development of a sequential model-based processor that captures both the underlying transport physics of gamma-ray emissions including Compton scattering and the measurement of photon energies offers a physics-based approach to attack this challenging problem. The inclusion of a basic radionuclide representationmore » of absorbed/scattered photons at a given energy along with interarrival times is used to extract the physics information available from the noisy measurements portable radiation detection systems used to interdict contraband. It is shown that this physics representation can incorporated scattering physics leading to an 'extended' model-based structure that can be used to develop an effective sequential detection technique. The resulting model-based processor is shown to perform quite well based on data obtained from a controlled experiment.« less

42 CFR 57.2211 - Waiver or suspension.

Code of Federal Regulations, 2011 CFR

2011-10-01

... period, such as problems of a personal nature; and (4) The extent to which the individual is practicing... whether to grant a waiver under this paragraph the extent to which the individual has problems of a personal nature, e.g., physical or mental disability, terminal illness in the family, or need for financial...

42 CFR 57.2211 - Waiver or suspension.

Code of Federal Regulations, 2010 CFR

2010-10-01

... period, such as problems of a personal nature; and (4) The extent to which the individual is practicing... whether to grant a waiver under this paragraph the extent to which the individual has problems of a personal nature, e.g., physical or mental disability, terminal illness in the family, or need for financial...

Contact interaction of thin-walled elements with an elastic layer and an infinite circular cylinder under torsion

NASA Astrophysics Data System (ADS)

Kanetsyan, E. G.; Mkrtchyan, M. S.; Mkhitaryan, S. M.

2018-04-01

We consider a class of contact torsion problems on interaction of thin-walled elements shaped as an elastic thin washer – a flat circular plate of small height – with an elastic layer, in particular, with a half-space, and on interaction of thin cylindrical shells with a solid elastic cylinder, infinite in both directions. The governing equations of the physical models of elastic thin washers and thin circular cylindrical shells under torsion are derived from the exact equations of mathematical theory of elasticity using the Hankel and Fourier transforms. Within the framework of the accepted physical models, the solution of the contact problem between an elastic washer and an elastic layer is reduced to solving the Fredholm integral equation of the first kind with a kernel representable as a sum of the Weber–Sonin integral and some integral regular kernel, while solving the contact problem between a cylindrical shell and solid cylinder is reduced to a singular integral equation (SIE). An effective method for solving the governing integral equations of these problems are specified.

A pressure relaxation closure model for one-dimensional, two-material Lagrangian hydrodynamics based on the Riemann problem

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

Kamm, James R; Shashkov, Mikhail J

2009-01-01

Despite decades of development, Lagrangian hydrodynamics of strengthfree materials presents numerous open issues, even in one dimension. We focus on the problem of closing a system of equations for a two-material cell under the assumption of a single velocity model. There are several existing models and approaches, each possessing different levels of fidelity to the underlying physics and each exhibiting unique features in the computed solutions. We consider the case in which the change in heat in the constituent materials in the mixed cell is assumed equal. An instantaneous pressure equilibration model for a mixed cell can be cast asmore » four equations in four unknowns, comprised of the updated values of the specific internal energy and the specific volume for each of the two materials in the mixed cell. The unique contribution of our approach is a physics-inspired, geometry-based model in which the updated values of the sub-cell, relaxing-toward-equilibrium constituent pressures are related to a local Riemann problem through an optimization principle. This approach couples the modeling problem of assigning sub-cell pressures to the physics associated with the local, dynamic evolution. We package our approach in the framework of a standard predictor-corrector time integration scheme. We evaluate our model using idealized, two material problems using either ideal-gas or stiffened-gas equations of state and compare these results to those computed with the method of Tipton and with corresponding pure-material calculations.« less

Using Laboratory Homework to Facilitate Skill Integration and Assess Understanding in Intermediate Physics Courses

NASA Astrophysics Data System (ADS)

Johnston, Marty; Jalkio, Jeffrey

2013-04-01

By the time students have reached the intermediate level physics courses they have been exposed to a broad set of analytical, experimental, and computational skills. However, their ability to independently integrate these skills into the study of a physical system is often weak. To address this weakness and assess their understanding of the underlying physical concepts we have introduced laboratory homework into lecture based, junior level theoretical mechanics and electromagnetics courses. A laboratory homework set replaces a traditional one and emphasizes the analysis of a single system. In an exercise, students use analytical and computational tools to predict the behavior of a system and design a simple measurement to test their model. The laboratory portion of the exercises is straight forward and the emphasis is on concept integration and application. The short student reports we collect have revealed misconceptions that were not apparent in reviewing the traditional homework and test problems. Work continues on refining the current problems and expanding the problem sets.

THE HOW AND WHY OF THE MOVEMENT SYSTEM AS THE IDENTITY OF PHYSICAL THERAPY

PubMed Central

2017-01-01

The Movement System was adopted as the identity of physical therapy as one of the 8 guiding principles accompanying the Vision Statement of 2013. At its inception physical therapy was considered more of a technical field rather than that of a professional field. Physicians were to diagnose the patient's problem and the therapist was to follow the prescription provided by the physician with the primary purpose being to relieve symptoms such as pain or muscle weakness. Even by the 1960's, the prescription became more of a referral and there was recognition that therapists were making decisions about the patient's treatment and discharge disposition. The role of the physical therapist in pathokinesiologic problems has been well accepted over the years but as insights are gained about the role of movement in musculoskeletal pain, the concept of kinesiopathologic problems is being defined. Whether the movement dysfunction is from a pathokinesiologic or a kinesiopathologic mechanisms, the underlying physiologic process is movement which is the composite action of the movement system. This article provides a brief discussion of the steps leading to promotion of the identity and the reasons that further defining and promoting the movement system as the body system for which physical therapists are responsible is necessary for the full recognition of the profession. As suggested by the kinesiopathologic concept of movement inducing pathology, physical therapists can address the cause of musculoskeletal problems and not just symptoms or consequences such as the pathoanatomic problem. Level of Evidence: 5 PMID:29158948

THE HOW AND WHY OF THE MOVEMENT SYSTEM AS THE IDENTITY OF PHYSICAL THERAPY.

PubMed

Sahrmann, Shirley

2017-11-01

The Movement System was adopted as the identity of physical therapy as one of the 8 guiding principles accompanying the Vision Statement of 2013. At its inception physical therapy was considered more of a technical field rather than that of a professional field. Physicians were to diagnose the patient's problem and the therapist was to follow the prescription provided by the physician with the primary purpose being to relieve symptoms such as pain or muscle weakness. Even by the 1960's, the prescription became more of a referral and there was recognition that therapists were making decisions about the patient's treatment and discharge disposition. The role of the physical therapist in pathokinesiologic problems has been well accepted over the years but as insights are gained about the role of movement in musculoskeletal pain, the concept of kinesiopathologic problems is being defined. Whether the movement dysfunction is from a pathokinesiologic or a kinesiopathologic mechanisms, the underlying physiologic process is movement which is the composite action of the movement system. This article provides a brief discussion of the steps leading to promotion of the identity and the reasons that further defining and promoting the movement system as the body system for which physical therapists are responsible is necessary for the full recognition of the profession. As suggested by the kinesiopathologic concept of movement inducing pathology, physical therapists can address the cause of musculoskeletal problems and not just symptoms or consequences such as the pathoanatomic problem. 5.

Exploratory research session on the quantization of the gravitational field. At the Institute for Theoretical Physics, Copenhagen, Denmark, June-July 1957

NASA Astrophysics Data System (ADS)

DeWitt, Bryce S.

2017-06-01

During the period June-July 1957 six physicists met at the Institute for Theoretical Physics of the University of Copenhagen in Denmark to work together on problems connected with the quantization of the gravitational field. A large part of the discussion was devoted to exposition of the individual work of the various participants, but a number of new results were also obtained. The topics investigated by these physicists are outlined in this report and may be grouped under the following main headings: The theory of measurement. Topographical problems in general relativity. Feynman quantization. Canonical quantization. Approximation methods. Special problems.

Parental physical illness as a risk for psychosocial maladjustment in children and adolescents: epidemiological findings from a national survey in Germany.

PubMed

Barkmann, Claus; Romer, Georg; Watson, Maggie; Schulte-Markwort, Michael

2007-01-01

The authors assessed the risk for psychosocial maladjustment in a population-based sample of dependent children of parents with serious physical illness. In the context of The Hamburg Health Survey, a wide range of data on current life situation and health status was collected from a representative sample of families with children and adolescents between 4 and 18 years old (N=1,950). For 4- to 18-year-old children and adolescents in Germany, the prevalence of a serious physical illness in a parent was 4.1%. The adjusted risk of psychosocial maladjustment in this target group, depending on the case definition, is elevated, with internalizing problems being more prevalent than externalizing problems. Although problems for affected boys decline with puberty, they increase for girls. In this age-group, girls and boys appear to be under particular strain when the respective same-sex parent has a serious physical illness. Exposure to serious parental physical illness is an epidemiologically relevant risk factor for psychosocial maladjustment in children and adolescents that needs to be better recognized by medical professionals.

Projected regression method for solving Fredholm integral equations arising in the analytic continuation problem of quantum physics

NASA Astrophysics Data System (ADS)

Arsenault, Louis-François; Neuberg, Richard; Hannah, Lauren A.; Millis, Andrew J.

2017-11-01

We present a supervised machine learning approach to the inversion of Fredholm integrals of the first kind as they arise, for example, in the analytic continuation problem of quantum many-body physics. The approach provides a natural regularization for the ill-conditioned inverse of the Fredholm kernel, as well as an efficient and stable treatment of constraints. The key observation is that the stability of the forward problem permits the construction of a large database of outputs for physically meaningful inputs. Applying machine learning to this database generates a regression function of controlled complexity, which returns approximate solutions for previously unseen inputs; the approximate solutions are then projected onto the subspace of functions satisfying relevant constraints. Under standard error metrics the method performs as well or better than the Maximum Entropy method for low input noise and is substantially more robust to increased input noise. We suggest that the methodology will be similarly effective for other problems involving a formally ill-conditioned inversion of an integral operator, provided that the forward problem can be efficiently solved.

Insufficient coping behavior under chronic stress and vulnerability to psychiatric disorders.

PubMed

Mohr, Christine; Braun, Silke; Bridler, René; Chmetz, Florian; Delfino, Juan P; Kluckner, Viktoria J; Lott, Petra; Schrag, Yann; Seifritz, Erich; Stassen, Hans H

2014-01-01

Epidemiological data indicate that 75% of subjects with major psychiatric disorders have their onset of illness in the age range of 17-24 years. An estimated 35-50% of college and university students drop out prematurely due to insufficient coping skills under chronic stress, while 85% of students receiving a psychiatric diagnosis withdraw from college/university prior to the completion of their education. In this study, we aimed at developing standardized means of identifying students with insufficient coping skills under chronic stress and at risk for mental health problems. A sample of 1,217 college students from 3 different sites in the USA and Switzerland completed 2 self-report questionnaires: the Coping Strategies Inventory (COPE) and the Zurich Health Questionnaire (ZHQ), which assesses 'regular exercises', 'consumption behavior', 'impaired physical health', 'psychosomatic disturbances' and 'impaired mental health'. The data were subjected to structure analyses by means of a neural network approach. We found 2 highly stable and reproducible COPE scales that explained the observed interindividual variation in coping behavior sufficiently well and in a socioculturally independent way. The scales reflected basic coping behavior in terms of 'activity-passivity' and 'defeatism-resilience', and in the sense of stable, socioculturally independent personality traits. Correlation analyses carried out for external validation revealed a close relationship between high scores on the defeatism scale and impaired physical and mental health. This underlined the role of insufficient coping behavior as a risk factor for physical and mental health problems. The combined COPE and ZHQ instruments appear to constitute powerful screening tools for insufficient coping skills under chronic stress and for risks of mental health problems.

Differentiation of direct and indirect socioeconomic effects on suicide attempts in South Korea

PubMed Central

Ki, Myung; Seong Sohn, Eui; An, Byungduck; Lim, Jiseun

2017-01-01

Abstract Despite the wide recognition of the inverse association between socioeconomic position (SEP) and suicidal behaviors, its underlying process and potential mediators are little known. This study investigated the pathway from SEP to suicide attempts with attention to potential mediators. From the Korean Health and Nutrition Examination Survey 2007–2013, which is a nationwide cross-sectional survey of the health and nutritional status, a total of 34,565 participants (≥30 years) were included in the analysis. To unfold the pathways linking SEP to suicide attempts, the direct and indirect effects of 3 SEP measures (educational attainment, household income, and occupational group) and 3 mediators (physical illness, mental health problems, and problematic drinking) were differentiated using structured equation model (SEM). Most of direct and indirect effects of educational attainment, household income, and occupational group on suicide attempts were significant; Nonemployment status had the largest total (β = 0.291, P < .01) and direct effects (β = 0.212, P < .01), while educational attainment had the largest indirect effect (β = −0.124, P < .01). Educational attainment was mainly mediated by physical illness and problem drinking, whereas household income and occupational group were mainly mediated by anxious or depressed mood and problem drinking. Physical illness played a major role in explaining suicide attempts, compared to mental health problem and problem drinking. Overall, experience of socioeconomic disadvantage increased suicide attempts independently of mental and physical problems. An extension of suicide prevention program is required for comprehensively targeting people with general problems such as physical illness and low SEP, complemented to narrowly targeting high risk group with, such as mental health problem. PMID:29390510

High-resolution coupled physics solvers for analysing fine-scale nuclear reactor design problems.

PubMed

Mahadevan, Vijay S; Merzari, Elia; Tautges, Timothy; Jain, Rajeev; Obabko, Aleksandr; Smith, Michael; Fischer, Paul

2014-08-06

An integrated multi-physics simulation capability for the design and analysis of current and future nuclear reactor models is being investigated, to tightly couple neutron transport and thermal-hydraulics physics under the SHARP framework. Over several years, high-fidelity, validated mono-physics solvers with proven scalability on petascale architectures have been developed independently. Based on a unified component-based architecture, these existing codes can be coupled with a mesh-data backplane and a flexible coupling-strategy-based driver suite to produce a viable tool for analysts. The goal of the SHARP framework is to perform fully resolved coupled physics analysis of a reactor on heterogeneous geometry, in order to reduce the overall numerical uncertainty while leveraging available computational resources. The coupling methodology and software interfaces of the framework are presented, along with verification studies on two representative fast sodium-cooled reactor demonstration problems to prove the usability of the SHARP framework.

High-resolution coupled physics solvers for analysing fine-scale nuclear reactor design problems

PubMed Central

Mahadevan, Vijay S.; Merzari, Elia; Tautges, Timothy; Jain, Rajeev; Obabko, Aleksandr; Smith, Michael; Fischer, Paul

2014-01-01

An integrated multi-physics simulation capability for the design and analysis of current and future nuclear reactor models is being investigated, to tightly couple neutron transport and thermal-hydraulics physics under the SHARP framework. Over several years, high-fidelity, validated mono-physics solvers with proven scalability on petascale architectures have been developed independently. Based on a unified component-based architecture, these existing codes can be coupled with a mesh-data backplane and a flexible coupling-strategy-based driver suite to produce a viable tool for analysts. The goal of the SHARP framework is to perform fully resolved coupled physics analysis of a reactor on heterogeneous geometry, in order to reduce the overall numerical uncertainty while leveraging available computational resources. The coupling methodology and software interfaces of the framework are presented, along with verification studies on two representative fast sodium-cooled reactor demonstration problems to prove the usability of the SHARP framework. PMID:24982250

Young Muslim Women's Experiences of Islam and Physical Education in Greece and Britain: A Comparative Study

ERIC Educational Resources Information Center

Dagkas, Symeon; Benn, Tansin

2006-01-01

Previous research suggests that Muslim women can experience particular problems when taking physical education (PE) lessons, for example with dress codes, mixed-teaching and exercise during Ramadan; and they can face restrictions in extra-curricular activities for cultural and religious reasons. The area is under-researched and there is little…

Additional Crime Scenes for Projectile Motion Unit

NASA Astrophysics Data System (ADS)

Fullerton, Dan; Bonner, David

2011-12-01

Building students' ability to transfer physics fundamentals to real-world applications establishes a deeper understanding of underlying concepts while enhancing student interest. Forensic science offers a great opportunity for students to apply physics to highly engaging, real-world contexts. Integrating these opportunities into inquiry-based problem solving in a team environment provides a terrific backdrop for fostering communication, analysis, and critical thinking skills. One such activity, inspired jointly by the museum exhibit "CSI: The Experience"2 and David Bonner's TPT article "Increasing Student Engagement and Enthusiasm: A Projectile Motion Crime Scene,"3 provides students with three different crime scenes, each requiring an analysis of projectile motion. In this lesson students socially engage in higher-order analysis of two-dimensional projectile motion problems by collecting information from 3-D scale models and collaborating with one another on its interpretation, in addition to diagramming and mathematical analysis typical to problem solving in physics.

Tracking student progress in a game-like physics learning environment with a Monte Carlo Bayesian knowledge tracing model

NASA Astrophysics Data System (ADS)

Gweon, Gey-Hong; Lee, Hee-Sun; Dorsey, Chad; Tinker, Robert; Finzer, William; Damelin, Daniel

2015-03-01

In tracking student learning in on-line learning systems, the Bayesian knowledge tracing (BKT) model is a popular model. However, the model has well-known problems such as the identifiability problem or the empirical degeneracy problem. Understanding of these problems remain unclear and solutions to them remain subjective. Here, we analyze the log data from an online physics learning program with our new model, a Monte Carlo BKT model. With our new approach, we are able to perform a completely unbiased analysis, which can then be used for classifying student learning patterns and performances. Furthermore, a theoretical analysis of the BKT model and our computational work shed new light on the nature of the aforementioned problems. This material is based upon work supported by the National Science Foundation under Grant REC-1147621 and REC-1435470.

Family Conflict, Emotional Security, and Child Development: Translating Research Findings into a Prevention Program for Community Families

ERIC Educational Resources Information Center

Cummings, E. Mark; Schatz, Julie N.

2012-01-01

The social problem posed by family conflict to the physical and psychological health and well-being of children, parents, and underlying family relationships is a cause for concern. Inter-parental and parent-child conflict are linked with children's behavioral, emotional, social, academic, and health problems, with children's risk particularly…

Children at risk of residual physical problems after public road traffic injuries--a 1-year follow-up study.

PubMed

Olofsson, Eva; Bunketorp, Olle; Andersson, Anna-Lena

2012-01-01

To describe the residual physical problems 1 year after traffic injuries in children with respect to age, gender, extraction (Swedish or foreign), type of care, type of accident and use of protective equipment, type of injury, and the impact on daily living activities. Hospital data were analysed for children, aged 15 or under, after road traffic accidents in the Gothenburg region in 2000. Age, gender, type of road user, counterpart, use of protective equipment, type and severity of each injury, and type of care were related to follow-up data obtained by a self-completed questionnaire answered 1 year after the accident. The AIS90 was used for injury classification. Residual physical problems were specified, graded, and mapped on anatomical pictures of the body by the respondents. Logistic regression was used to explore independent factors for residual problems. A total of 341 children (81%) fulfilled the study. Cyclists dominated, 60%, followed by moped users, car occupants and pedestrians. The mean age was 11 years, 61% were boys, 16% were of foreign extraction, 26% were treated as inpatients, and 11% had at least one serious (AIS3+) injury. Residual problems were reported for 16% of the study group (n=53), and of these 31% were located to the lower extremities (mostly knee problems), upper extremities in 20%, face in 14%, neck in 14%, upper trunk in 8%, lower trunk in 8%, and skull/brain in 3%. Significant permanent impairment was reported in one case. Cyclists reported problems significantly less frequently than others. Children reporting problems tended to be older and were most often injured as moped users. Problems to the neck and the upper trunk were reported to a higher rate than the injury rate in these regions. Children with residual problems reported limitations in daily living activities after the accident more often than those without residual physical problems. Residual physical problems were reported in about one sixth of the study group, few with serious problems. The risk of residual problems should be recognised in older children, especially after moped accidents, and also in children with neck problems. Copyright © 2010 Elsevier Ltd. All rights reserved.

The Role of Specific Alcohol-Related Problems in Predicting Depressive Experiences in a Cross-Sectional National Household Survey.

PubMed

McBride, Orla; Cheng, Hui G; Slade, Tim; Lynskey, Michael T

2016-11-01

This study examines the type of alcohol-related problems that commonly occur before the onset of depressive experiences to shed light on the mechanisms underlying the alcohol-depression comorbidity relationship. Data were from the 1992 USA National Longitudinal Alcohol Epidemiologic Survey. Analytical sample comprised of drinkers with a prior to past year (PPY) history of alcohol-related problems with or without any experiences of depressed mood in the past year (PY). The prevalence of PPY alcohol-related problems was examined, as well as the ability of specific alcohol problems to predict PY experiences of depressed mood. The type of depressed mood experienced by drinkers with PPY history of alcohol-related problems was compared to those without. All but one alcohol-related problem PPY was more frequently endorsed among drinkers with PY experiences of depressed mood. Controlling for confounders, five alcohol-related problems experienced PPY were significantly predictive of depressed mood PY: tolerance, drinking longer than intended, inability to perform important social and occupational roles/obligations, as well as drinking in physically hazardous situations. Drinkers with alcohol-related problems PPY more frequently experienced difficulties with concentration, energy, and thoughts of death, than those without. Alcohol-related problems are likely associated with depressive experiences through a complex network, whereby experiences of physical dependence and negative consequences increase the likelihood of negative affect. Novel study designs are necessary to fully understand the complex mechanisms underlying this comorbidity. © The Author 2016. Medical Council on Alcohol and Oxford University Press. All rights reserved.

Artificial intelligence: Deep neural reasoning

NASA Astrophysics Data System (ADS)

Jaeger, Herbert

2016-10-01

The human brain can solve highly abstract reasoning problems using a neural network that is entirely physical. The underlying mechanisms are only partially understood, but an artificial network provides valuable insight. See Article p.471

Superheavy Elements

ERIC Educational Resources Information Center

Tsang, Chin Fu

1975-01-01

Discusses the possibility of creating elements with an atomic number of around 114. Describes the underlying physics responsible for the limited extent of the periodic table and enumerates problems that must be overcome in creating a superheavy nucleus. (GS)

Applying automatic item generation to create cohesive physics testlets

NASA Astrophysics Data System (ADS)

Mindyarto, B. N.; Nugroho, S. E.; Linuwih, S.

2018-03-01

Computer-based testing has created the demand for large numbers of items. This paper discusses the production of cohesive physics testlets using an automatic item generation concepts and procedures. The testlets were composed by restructuring physics problems to reveal deeper understanding of the underlying physical concepts by inserting a qualitative question and its scientific reasoning question. A template-based testlet generator was used to generate the testlet variants. Using this methodology, 1248 testlet variants were effectively generated from 25 testlet templates. Some issues related to the effective application of the generated physics testlets in practical assessments were discussed.

Therapeutic and Ethical Dilemma of Puberty and Menstruation Problems in an Intellectually Disabled (Autistic) Female: a Case Report.

PubMed

Memarian, Azadeh; Mehrpisheh, Shahrokh

2015-10-01

Intellectual disability is a term used when a person has certain limitations in mental functioning and skills. Autism is a group of developmental brain disorders, collectively called autism spectrum disorder (ASD). Teenagers with learning and physical disabilities are more likely to have menstrual problems compared to the general populations. The parents of a 12-year-old girl with autism spectrum disorder and intellectual disability referred to the coroner due to her numerous problems of puberty (menstruation) including: poor hygiene and polluting herself and the environment, not allowing to put or change the pads and changes in mood and physical health prior period, requested for the surgery (hysterectomy). In legal medicine organization after reviewing the medical records, physical exams and medical consultations with a gynecologist and psychiatric, surgery was not accepted. Hysterectomy (surgery) due to the age of the child, either physically or morally is not recommended. The use of hormone replacement therapy has side effects such as osteoporosis. In these cases, it seems noninvasive methods (behavioral therapy and learning care skills) under the welfare experts is also more effective and morally.

Magnetic Interactions and the Method of Images: A Wealth of Educational Suggestions

ERIC Educational Resources Information Center

Bonanno, A.; Camarca, M.; Sapia, P.

2011-01-01

Under some conditions, the method of images (well known in electrostatics) may be implemented in magnetostatic problems too, giving an excellent example of the usefulness of formal analogies in the description of physical systems. In this paper, we develop a quantitative model for the magnetic interactions underlying the so-called Geomag[TM]…

Construction Method of Analytical Solutions to the Mathematical Physics Boundary Problems for Non-Canonical Domains

NASA Astrophysics Data System (ADS)

Mobarakeh, Pouyan Shakeri; Grinchenko, Victor T.

2015-06-01

The majority of practical cases of acoustics problems requires solving the boundary problems in non-canonical domains. Therefore construction of analytical solutions of mathematical physics boundary problems for non-canonical domains is both lucrative from the academic viewpoint, and very instrumental for elaboration of efficient algorithms of quantitative estimation of the field characteristics under study. One of the main solving ideologies for such problems is based on the superposition method that allows one to analyze a wide class of specific problems with domains which can be constructed as the union of canonically-shaped subdomains. It is also assumed that an analytical solution (or quasi-solution) can be constructed for each subdomain in one form or another. However, this case implies some difficulties in the construction of calculation algorithms, insofar as the boundary conditions are incompletely defined in the intervals, where the functions appearing in the general solution are orthogonal to each other. We discuss several typical examples of problems with such difficulties, we study their nature and identify the optimal methods to overcome them.

Sandia National Laboratories analysis code data base

NASA Astrophysics Data System (ADS)

Peterson, C. W.

1994-11-01

Sandia National Laboratories' mission is to solve important problems in the areas of national defense, energy security, environmental integrity, and industrial technology. The laboratories' strategy for accomplishing this mission is to conduct research to provide an understanding of the important physical phenomena underlying any problem, and then to construct validated computational models of the phenomena which can be used as tools to solve the problem. In the course of implementing this strategy, Sandia's technical staff has produced a wide variety of numerical problem-solving tools which they use regularly in the design, analysis, performance prediction, and optimization of Sandia components, systems, and manufacturing processes. This report provides the relevant technical and accessibility data on the numerical codes used at Sandia, including information on the technical competency or capability area that each code addresses, code 'ownership' and release status, and references describing the physical models and numerical implementation.

Toward Paradoxical Inconsistency in Electrostatics of Metallic Conductors

DTIC Science & Technology

Naturally, when dealing with fundamental problems, the V and V effort should include careful exploration and, if necessary, revision of the fundamentals...Current developments show a clear trend toward more serious efforts in validation and verification (V and V) of physical and engineering models...underlying the physics. With this understanding in mind, we review some fundamentals of the models of crystalline electric conductors and find a

25 CFR 20.401 - What is included under Services to Children, Elderly, and Families?

Code of Federal Regulations, 2014 CFR

2014-04-01

... family functioning and interpersonal relationships; (b) Referral to the appropriate resource for problems related to illness, physical or mental handicaps, drug abuse, alcoholism, and violation of the law; and (c...

25 CFR 20.401 - What is included under Services to Children, Elderly, and Families?

Code of Federal Regulations, 2012 CFR

2012-04-01

... family functioning and interpersonal relationships; (b) Referral to the appropriate resource for problems related to illness, physical or mental handicaps, drug abuse, alcoholism, and violation of the law; and (c...

25 CFR 20.401 - What is included under Services to Children, Elderly, and Families?

Code of Federal Regulations, 2013 CFR

2013-04-01

... family functioning and interpersonal relationships; (b) Referral to the appropriate resource for problems related to illness, physical or mental handicaps, drug abuse, alcoholism, and violation of the law; and (c...

25 CFR 20.401 - What is included under Services to Children, Elderly, and Families?

Code of Federal Regulations, 2011 CFR

2011-04-01

... family functioning and interpersonal relationships; (b) Referral to the appropriate resource for problems related to illness, physical or mental handicaps, drug abuse, alcoholism, and violation of the law; and (c...

Menstrual Cycle: What's Normal, What's Not

MedlinePlus

... loss or excessive exercising. Eating disorders — such as anorexia nervosa — extreme weight loss and increased physical activity can ... Treatment for any underlying problems, such as an eating disorder, also might help. However, some menstrual irregularities can' ...

Estimation of Dynamical Parameters in Atmospheric Data Sets

NASA Technical Reports Server (NTRS)

Wenig, Mark O.

2004-01-01

In this study a new technique is used to derive dynamical parameters out of atmospheric data sets. This technique, called the structure tensor technique, can be used to estimate dynamical parameters such as motion, source strengths, diffusion constants or exponential decay rates. A general mathematical framework was developed for the direct estimation of the physical parameters that govern the underlying processes from image sequences. This estimation technique can be adapted to the specific physical problem under investigation, so it can be used in a variety of applications in trace gas, aerosol, and cloud remote sensing. The fundamental algorithm will be extended to the analysis of multi- channel (e.g. multi trace gas) image sequences and to provide solutions to the extended aperture problem. In this study sensitivity studies have been performed to determine the usability of this technique for data sets with different resolution in time and space and different dimensions.

What your mother never told you about ... physics teaching

NASA Astrophysics Data System (ADS)

Roudebush, Deborah

2010-03-01

When I entered high school teaching after working in industry for several years, I was sure I knew exactly what to do. I was convinced that I would be the sage on the stage and would wow the students with my clear explanations, amazing problem-solving techniques, and perfect lab instructions. I was convinced that the students would soak up the wisdom and insight that I was offering and that, if the students just followed my directions exactly, they would be able to solve new and exciting problems. Instead, I found that the students became amazingly adept at applied mathematics and understood few of the underlying physics concepts. In fact, some of my star students who headed off to become physics majors were unprepared for the thought required and changed majors within two years.

High-resolution coupled physics solvers for analysing fine-scale nuclear reactor design problems

DOE PAGES

Mahadevan, Vijay S.; Merzari, Elia; Tautges, Timothy; ...

2014-06-30

An integrated multi-physics simulation capability for the design and analysis of current and future nuclear reactor models is being investigated, to tightly couple neutron transport and thermal-hydraulics physics under the SHARP framework. Over several years, high-fidelity, validated mono-physics solvers with proven scalability on petascale architectures have been developed independently. Based on a unified component-based architecture, these existing codes can be coupled with a mesh-data backplane and a flexible coupling-strategy-based driver suite to produce a viable tool for analysts. The goal of the SHARP framework is to perform fully resolved coupled physics analysis of a reactor on heterogeneous geometry, in ordermore » to reduce the overall numerical uncertainty while leveraging available computational resources. Finally, the coupling methodology and software interfaces of the framework are presented, along with verification studies on two representative fast sodium-cooled reactor demonstration problems to prove the usability of the SHARP framework.« less

Evaluation of coupling approaches for thermomechanical simulations

DOE PAGES

Novascone, S. R.; Spencer, B. W.; Hales, J. D.; ...

2015-08-10

Many problems of interest, particularly in the nuclear engineering field, involve coupling between the thermal and mechanical response of an engineered system. The strength of the two-way feedback between the thermal and mechanical solution fields can vary significantly depending on the problem. Contact problems exhibit a particularly high degree of two-way feedback between those fields. This paper describes and demonstrates the application of a flexible simulation environment that permits the solution of coupled physics problems using either a tightly coupled approach or a loosely coupled approach. In the tight coupling approach, Newton iterations include the coupling effects between all physics,more » while in the loosely coupled approach, the individual physics models are solved independently, and fixed-point iterations are performed until the coupled system is converged. These approaches are applied to simple demonstration problems and to realistic nuclear engineering applications. The demonstration problems consist of single and multi-domain thermomechanics with and without thermal and mechanical contact. Simulations of a reactor pressure vessel under pressurized thermal shock conditions and a simulation of light water reactor fuel are also presented. Here, problems that include thermal and mechanical contact, such as the contact between the fuel and cladding in the fuel simulation, exhibit much stronger two-way feedback between the thermal and mechanical solutions, and as a result, are better solved using a tight coupling strategy.« less

Effects of early menarche on physical and psychosocial health problems in adolescent girls and adult women

PubMed Central

2016-01-01

The menarcheal age of Korean women has been rapidly decreasing for the last 50 years, and the average menarcheal age of women born in the 1990s is approaching 12.6 years. In addition, interest in early puberty has been increasing recently owing to the rapid increase in precocious puberty. Generally, out of concern for short stature and early menarche, idiopathic central precocious puberty in female adolescents is treated with gonadotropin-releasing hormone analogs. Studies to date have described the association between early menarche and psychosocial problems such as delinquency and risky sexual behavior, as well as physical health problems such as obesity, diabetes, cardiovascular diseases, and breast cancer throughout the lifespan of women. However, the pathophysiological mechanism underlying this association has not been clarified thus far. In this article, we review and discuss the existing literature to describe the current understanding of the effects of early menarche on the physical and psychosocial health of adolescent girls and adult women. PMID:27721839

Numerical and analytical approaches to an advection-diffusion problem at small Reynolds number and large Péclet number

NASA Astrophysics Data System (ADS)

Fuller, Nathaniel J.; Licata, Nicholas A.

2018-05-01

Obtaining a detailed understanding of the physical interactions between a cell and its environment often requires information about the flow of fluid surrounding the cell. Cells must be able to effectively absorb and discard material in order to survive. Strategies for nutrient acquisition and toxin disposal, which have been evolutionarily selected for their efficacy, should reflect knowledge of the physics underlying this mass transport problem. Motivated by these considerations, in this paper we discuss the results from an undergraduate research project on the advection-diffusion equation at small Reynolds number and large Péclet number. In particular, we consider the problem of mass transport for a Stokesian spherical swimmer. We approach the problem numerically and analytically through a rescaling of the concentration boundary layer. A biophysically motivated first-passage problem for the absorption of material by the swimming cell demonstrates quantitative agreement between the numerical and analytical approaches. We conclude by discussing the connections between our results and the design of smart toxin disposal systems.

Intermittency and random matrices

NASA Astrophysics Data System (ADS)

Sokoloff, Dmitry; Illarionov, E. A.

2015-08-01

A spectacular phenomenon of intermittency, i.e. a progressive growth of higher statistical moments of a physical field excited by an instability in a random medium, attracted the attention of Zeldovich in the last years of his life. At that time, the mathematical aspects underlying the physical description of this phenomenon were still under development and relations between various findings in the field remained obscure. Contemporary results from the theory of the product of independent random matrices (the Furstenberg theory) allowed the elaboration of the phenomenon of intermittency in a systematic way. We consider applications of the Furstenberg theory to some problems in cosmology and dynamo theory.

Understanding Coreference in a System for Solving Physics Word Problems.

NASA Astrophysics Data System (ADS)

Bulko, William Charles

In this thesis, a computer program (BEATRIX) is presented which takes as input an English statement of a physics problem and a figure associated with it, understands the two kinds of input in combination, and produces a data structure containing a model of the physical objects described and the relationships between them. BEATRIX provides a mouse-based graphic interface with which the user sketches a picture and enters English sentences; meanwhile, BEATRIX creates a neutral internal representation of the picture similar to the which might be produced as the output of a vision system. It then parses the text and the picture representation, resolves the references between objects common to the two data sources, and produces a unified model of the problem world. The correctness and completeness of this model has been validated by applying it as input to a physics problem-solving program currently under development. Two descriptions of a world are said to be coreferent when they contain references to overlapping sets of objects. Resolving coreferences to produce a correct world model is a common task in scientific and industrial problem-solving: because English is typically not a good language for expressing spatial relationships, people in these fields frequently use diagrams to supplement textual descriptions. Elementary physics problems from college-level textbooks provide a useful and convenient domain for exploring the mechanisms of coreference. Because flexible, opportunistic control is necessary in order to recognize coreference and to act upon it, the understanding module of BEATRIX uses a blackboard control structure. The blackboard knowledge sources serve to identify physical objects in the picture, parse the English text, and resolve coreferences between the two. We believed that BEATRIX demonstrates a control structure and collection of knowledge that successfully implements understanding of text and picture by computer. We also believe that this organization can be applied successfully to similar understanding tasks in domains other than physics problem -solving, where data such as the output from vision systems and speech understanders can be used in place of text and pictures.

From lepton protoplasm to the genesis of hadrons

NASA Astrophysics Data System (ADS)

Eliseev, S. M.; Kosmachev, O. S.

2016-01-01

Theory of matter under extreme conditions opens a new stage in particle physics. It is necessary here to combine Dirac's elementary particle physics with Prigogine's dynamics of nonequilibrium systems. In the article we discuss the problem of the hierarchy of complexity. What can be considered as the lowest level of the organization of extreme matter on the basis of which the self-organization of the complex form occur?

Data-Aware Retrodiction for Asynchronous Harmonic Measurement in a Cyber-Physical Energy System.

PubMed

Liu, Youda; Wang, Xue; Liu, Yanchi; Cui, Sujin

2016-08-18

Cyber-physical energy systems provide a networked solution for safety, reliability and efficiency problems in smart grids. On the demand side, the secure and trustworthy energy supply requires real-time supervising and online power quality assessing. Harmonics measurement is necessary in power quality evaluation. However, under the large-scale distributed metering architecture, harmonic measurement faces the out-of-sequence measurement (OOSM) problem, which is the result of latencies in sensing or the communication process and brings deviations in data fusion. This paper depicts a distributed measurement network for large-scale asynchronous harmonic analysis and exploits a nonlinear autoregressive model with exogenous inputs (NARX) network to reorder the out-of-sequence measuring data. The NARX network gets the characteristics of the electrical harmonics from practical data rather than the kinematic equations. Thus, the data-aware network approximates the behavior of the practical electrical parameter with real-time data and improves the retrodiction accuracy. Theoretical analysis demonstrates that the data-aware method maintains a reasonable consumption of computing resources. Experiments on a practical testbed of a cyber-physical system are implemented, and harmonic measurement and analysis accuracy are adopted to evaluate the measuring mechanism under a distributed metering network. Results demonstrate an improvement of the harmonics analysis precision and validate the asynchronous measuring method in cyber-physical energy systems.

Challenge of engaging all students via self-paced interactive electronic learning tutorials for introductory physics

NASA Astrophysics Data System (ADS)

DeVore, Seth; Marshman, Emily; Singh, Chandralekha

2017-06-01

As research-based, self-paced electronic learning tools become increasingly available, a critical issue educators encounter is implementing strategies to ensure that all students engage with them as intended. Here, we first discuss the effectiveness of electronic learning tutorials as self-paced learning tools in large enrollment brick and mortar introductory physics courses and then propose a framework for helping students engage effectively with the learning tools. The tutorials were developed via research in physics education and were found to be effective for a diverse group of introductory physics students in one-on-one implementation. Instructors encouraged the use of these tools in a self-paced learning environment by telling students that they would be helpful for solving the assigned homework problems and that the underlying physics principles in the tutorial problems would be similar to those in the in-class quizzes (which we call paired problems). We find that many students in the courses in which these interactive electronic learning tutorials were assigned as a self-study tool performed poorly on the paired problems. In contrast, a majority of student volunteers in one-on-one implementation greatly benefited from the tutorials and performed well on the paired problems. The significantly lower overall performance on paired problems administered as an in-class quiz compared to the performance of student volunteers who used the research-based tutorials in one-on-one implementation suggests that many students enrolled in introductory physics courses did not effectively engage with the tutorials outside of class and may have only used them superficially. The findings suggest that many students in need of out-of-class remediation via self-paced learning tools may have difficulty motivating themselves and may lack the self-regulation and time-management skills to engage effectively with tools specially designed to help them learn at their own pace. We conclude by proposing a theoretical framework to help students with diverse prior preparations engage effectively with self-paced learning tools.

Projected Regression Methods for Inverting Fredholm Integrals: Formalism and Application to Analytical Continuation

NASA Astrophysics Data System (ADS)

Arsenault, Louis-Francois; Neuberg, Richard; Hannah, Lauren A.; Millis, Andrew J.

We present a machine learning-based statistical regression approach to the inversion of Fredholm integrals of the first kind by studying an important example for the quantum materials community, the analytical continuation problem of quantum many-body physics. It involves reconstructing the frequency dependence of physical excitation spectra from data obtained at specific points in the complex frequency plane. The approach provides a natural regularization in cases where the inverse of the Fredholm kernel is ill-conditioned and yields robust error metrics. The stability of the forward problem permits the construction of a large database of input-output pairs. Machine learning methods applied to this database generate approximate solutions which are projected onto the subspace of functions satisfying relevant constraints. We show that for low input noise the method performs as well or better than Maximum Entropy (MaxEnt) under standard error metrics, and is substantially more robust to noise. We expect the methodology to be similarly effective for any problem involving a formally ill-conditioned inversion, provided that the forward problem can be efficiently solved. AJM was supported by the Office of Science of the U.S. Department of Energy under Subcontract No. 3F-3138 and LFA by the Columbia Univeristy IDS-ROADS project, UR009033-05 which also provided part support to RN and LH.

Investigating the Usability and Efficacy of Customizable Computer Coaches for Introductory Physics Problem Solving

NASA Astrophysics Data System (ADS)

Aryal, Bijaya

2016-03-01

We have studied the impacts of web-based Computer Coaches on educational outputs and outcomes. This presentation will describe the technical and conceptual framework related to the Coaches and discuss undergraduate students' favorability of the Coaches. Moreover, its impacts on students' physics problem solving performance and on their conceptual understanding of physics will be reported. We used a qualitative research technique to collect and analyze interview data from 19 undergraduate students who used the Coaches in the interview setting. The empirical results show that the favorability and efficacy of the Computer Coaches differ considerably across students of different educational backgrounds, preparation levels, attitudes and epistemologies about physics learning. The interview data shows that female students tend to have more favorability supporting the use of the Coach. Likewise, our assessment suggests that female students seem to benefit more from the Coaches in their problem solving performance and in conceptual learning of physics. Finally, the analysis finds evidence that the Coach has potential for increasing efficiency in usage and for improving students' educational outputs and outcomes under its customized usage. This work was partially supported by the Center for Educational Innovation, Office of the Senior Vice President for Academic Affairs and Provost, University of Minnesota.

Scientific session of the General meeting of the Physical Sciences Division of the Russian Academy of Sciences (7 December 2015)

NASA Astrophysics Data System (ADS)

2016-05-01

A scientific session of the General meeting of the Physical Sciences Division of the Russian Academy of Sciences (RAS) was held in the conference hall of the Lebedev Physical Institute, RAS on 7 December 2015. The papers collected in this issue were written based on talks given at the session (the program of the session is available on the RAS Physical Sciences Division website http://www.gpad.ac.ru). (1) Loshchenov V B (Prokhorov General Physics Institute, RAS, Moscow) "Pharmacodynamics of a nanophotosensitizer under irradiation by an electromagnetic field: from THz to Cherenkov radiation"; (2) Zhuikov B L (Institute for Nuclear Research, RAS, Moscow) "Successes and problems in the development of medical radioisotope production in Russia"; (3) Tikhonov Yu A (Budker Institute of Nuclear Physics, SB RAS, Novosibirsk) "Applying nuclear physics methods in healthcare"; (4) Turchin I V (Institute of Applied Physics, RAS, Nizhny Novgorod) "Methods of biomedical optical imaging: from subcellular structures to tissues and organs"; (5) Breus T K, Petrukovich A A (Space Research Institute, RAS, Moscow), Binhi V N (Prokhorov General Physics Institute, RAS, Moscow; Lomonosov Moscow State University, Moscow) "Magnetic factor in solar-terrestrial relations and its impact on the human body: physical problems and prospects for research"; (6) Makarov D I (Special Astrophysical Observatory, RAS, Nizhnii Arkhyz, Zelenchukskii region, Karachai-Cherkessian Republic) "Studying the Local University". Papers based on oral reports 2, 4, and 5 are presented below. • Successes and problems in the development of medical radioisotope production in Russia, B L Zhuikov Physics-Uspekhi, 2016, Volume 59, Number 5, Pages 481-486 • Methods of biomedical optical imaging: from subcellular structures to tissues and organs, I V Turchin Physics-Uspekhi, 2016, Volume 59, Number 5, Pages 487-501 • Magnetic factor in solar-terrestrial relations and its impact on the human body: physical problems and prospects for research, T K Breus, V N Binhi, A A Petrukovich Physics-Uspekhi, 2016, Volume 59, Number 5, Pages 502-510

Conservation Laws in Weak Interactions

DOE R&D Accomplishments Database

Lee, T. D.

1957-03-01

Notes are presented on four lectures given at Harvard University in March 1957 on elementary particle physics, the theta-tau problem, validity of parity conservation, tests for invariance under P, C, and T, and the two-component theory of the neutrino. (W.D.M.)

Transfer of Problem Solving Skills from Touchscreen to 3D Model by 3- to 6-Year-Olds

PubMed Central

Tarasuik, Joanne; Demaria, Ana; Kaufman, Jordy

2017-01-01

Although much published research purports that young children struggle to solve problems from screen-based media and to transfer learning from a virtual to a physical modality, Huber et al. (2016)’s recent study on children solving the Tower of Hanoi (ToH) problem on a touchscreen app offers a clear counter example. Huber et al. (2016) reported that children transferred learning from media to the physical world. As this finding arguably differs from that of prior research in this area, the current study tests whether the Huber et al. (2016) results could be replicated. Additionally, we extended the scope of the Huber et al. (2016) work by testing a broader age range, including children as young as 3 years, and using a culturally distinct participant pool. The results of the current study verified Huber et al.’s (2016) conclusion that 4- to 6-year-old children are capable of transferring the ToH learning from touchscreen devices to the physical version of the puzzle. Children under 4 years of age, in contrast, showed little ability to improve at the ToH problem regardless of the practice modality—suggesting that a different problem-solving task is required to probe very young children’s ability to learn from touchscreen apps. PMID:28979222

Cluster expansion for ground states of local Hamiltonians

NASA Astrophysics Data System (ADS)

Bastianello, Alvise; Sotiriadis, Spyros

2016-08-01

A central problem in many-body quantum physics is the determination of the ground state of a thermodynamically large physical system. We construct a cluster expansion for ground states of local Hamiltonians, which naturally incorporates physical requirements inherited by locality as conditions on its cluster amplitudes. Applying a diagrammatic technique we derive the relation of these amplitudes to thermodynamic quantities and local observables. Moreover we derive a set of functional equations that determine the cluster amplitudes for a general Hamiltonian, verify the consistency with perturbation theory and discuss non-perturbative approaches. Lastly we verify the persistence of locality features of the cluster expansion under unitary evolution with a local Hamiltonian and provide applications to out-of-equilibrium problems: a simplified proof of equilibration to the GGE and a cumulant expansion for the statistics of work, for an interacting-to-free quantum quench.

Magnetohydrodynamics Carreau nanofluid flow over an inclined convective heated stretching cylinder with Joule heating

NASA Astrophysics Data System (ADS)

Khan, Imad; Shafquatullah; Malik, M. Y.; Hussain, Arif; Khan, Mair

Current work highlights the computational aspects of MHD Carreau nanofluid flow over an inclined stretching cylinder with convective boundary conditions and Joule heating. The mathematical modeling of physical problem yields nonlinear set of partial differential equations. A suitable scaling group of variables is employed on modeled equations to convert them into non-dimensional form. The integration scheme Runge-Kutta-Fehlberg on the behalf of shooting technique is utilized to solve attained set of equations. The interesting aspects of physical problem (linear momentum, energy and nanoparticles concentration) are elaborated under the different parametric conditions through graphical and tabular manners. Additionally, the quantities (local skin friction coefficient, local Nusselt number and local Sherwood number) which are responsible to dig out the physical phenomena in the vicinity of stretched surface are computed and delineated by varying controlling flow parameters.

Differences in the Processes of Solving Physics Problems between Good Physics Problem Solvers and Poor Physics Problem Solvers.

ERIC Educational Resources Information Center

Finegold, M.; Mass, R.

1985-01-01

Good problem solvers and poor problem solvers in advanced physics (N=8) were significantly different in their ability in translating, planning, and physical reasoning, as well as in problem solving time; no differences in reliance on algebraic solutions and checking problems were noted. Implications for physics teaching are discussed. (DH)

Career Opportunities for Physicists in the Micro Electronics Industry

NASA Astrophysics Data System (ADS)

Bourianoff, George

1997-10-01

The US micro electronics industry anticipates growth of 20 to 30 percent per year for the next five years. The need for engineers and scientists poses a critical problem for the industry but conversely presents great opportunities for those in closely related fields such as physics where career opportunities may be more limited. There is no shortage of important and challenging problems on the Semiconductor Institute of America (SIA) roadmap which will require solution in the next 10 years and which require expertise in the physical sciences. However, significant cultural differences exist between the physics community and the engineering oriented semiconductor community which must be understood and addressed in order for a physicist to successfully contribute in this environment. This talk will identify some of those cultural differences and describe some of the critical physics related problems which must be solved. Critical roadblocks include lithographic patterning below 0.18m. and design of Very Large Scale Integrated (VLSI) circuits in the deep submicron regime. The former will require developing radiation sources and optical elements for the EUV or XRAY part of the spectrum. The latter will require incorporating electromagnetic field equations with traditional lumped element circuit design methods. The cultural barriers alluded to earlier involve the manner in which engineering detail is approached. A physicist's basic instinct is to strip off the detail in order to make a problem mathematically tractable. This enables understanding of the underlying physical relationships but does not yield the quantitative detail necessary in semiconductor production.

Memory-dependent derivatives for photothermal semiconducting medium in generalized thermoelasticity with two-temperature

NASA Astrophysics Data System (ADS)

Lotfy, K.; Sarkar, N.

2017-11-01

In this work, a novel generalized model of photothermal theory with two-temperature thermoelasticity theory based on memory-dependent derivative (MDD) theory is performed. A one-dimensional problem for an elastic semiconductor material with isotropic and homogeneous properties has been considered. The problem is solved with a new model (MDD) under the influence of a mechanical force with a photothermal excitation. The Laplace transform technique is used to remove the time-dependent terms in the governing equations. Moreover, the general solutions of some physical fields are obtained. The surface taken into consideration is free of traction and subjected to a time-dependent thermal shock. The numerical Laplace inversion is used to obtain the numerical results of the physical quantities of the problem. Finally, the obtained results are presented and discussed graphically.

The Science Shop for Physics: an interface between practical problems in society and physical knowledge

NASA Astrophysics Data System (ADS)

van den Berg, G. P.

1998-03-01

Since some 20 years most Dutch universities have one or more science shops. Central shops handle research questions for all disciplines. Specialized shops are part of a department of chemistry or medicine, history, social science, etc. The shops have evolved rather differently, but their main mission still is to help social groups that lack money and have no easy access to scientific knowledge, e.g. neighbourhood, environmental, third world or patient groups. Most also help non-commercial organizations such as schools, trade unions or local authorities. Low-cost help can be provided because students do the work as part of their training, mainly in student projects (literature search, practical work, graduation, etc.). A total staff of 80, helped by 600 students, 250 voluntary and 50 paid researchers, handle 1500 questions resulting in 300 reports (estimated figures 1995). Science shops for physics (`Physics Shop', PS) have to deal with practical problems, generally involving classical physics. Major topics are noise, vibration, radiation, indoor climate and energy: most of the work lies in estimating/measuring relevant parameters, assessing impact, seeking solutions. The 3 Dutch PS's have developed in different directions. One is run entirely by students and deals with small, concrete problems. The second PS is managed by a co-ordinator who mediates between client groups and physics staff members who assist students in small and larger projects. The third has a lot of in-house expertise, and the shop staff is in direct contact with client groups as well as students who work in the PS itself. In questions submitted to the PS it is not always immediately clear what to do or how to do it because of the non-scientific phrasing of the problems and problems include non-physical (e.g. technical, health or legal) aspects. Also, difficulties in solving the problems are typically not in the underlying physics, but in the lack of accurate data and of control of the complex environment. However, these very aspects are important from an educational point of view. Through these problems students (and physicists) may gain more insight into how lay people percieve and make use of science, and into the position of science in relation to other ways in which people try to understand their world.

Physical exam of the adolescent shoulder: tips for evaluating and diagnosing common shoulder disorders in the adolescent athlete.

PubMed

Lazaro, Lionel E; Cordasco, Frank A

2017-02-01

In the young athlete, the shoulder is one of the most frequently injured joints during sports activities. The injuries are either from an acute traumatic event or overuse. Shoulder examination can present some challenges; given the multiple joints involved, the difficulty palpating the underlying structures, and the potential to have both intra- and/or extra-articular problems. Many of the shoulder examination tests can be positive in multiple problems. They usually have high sensitivity but low specificity and therefore low predictive value. The medical history coupled with a detailed physical exam can usually provide the information necessary to obtain an accurate diagnosis. A proficient shoulder examination and the development of an adequate differential diagnosis are important before considering advanced imaging. The shoulder complex relies upon the integrity of multiple structures for normal function. A detailed history is of paramount importance when evaluating young athletes with shoulder problems. A systematic physical examination is extremely important to guiding an accurate diagnosis. The patient's age and activity level are very important when considering the differential diagnosis. Findings obtain through history and physical examination should dictate the decision to obtain advanced imaging of the shoulder.

Efficient decision-making by volume-conserving physical object

NASA Astrophysics Data System (ADS)

Kim, Song-Ju; Aono, Masashi; Nameda, Etsushi

2015-08-01

Decision-making is one of the most important intellectual abilities of not only humans but also other biological organisms, helping their survival. This ability, however, may not be limited to biological systems and may be exhibited by physical systems. Here we demonstrate that any physical object, as long as its volume is conserved when coupled with suitable operations, provides a sophisticated decision-making capability. We consider the multi-armed bandit problem (MBP), the problem of finding, as accurately and quickly as possible, the most profitable option from a set of options that gives stochastic rewards. Efficient MBP solvers are useful for many practical applications, because MBP abstracts a variety of decision-making problems in real-world situations in which an efficient trial-and-error is required. These decisions are made as dictated by a physical object, which is moved in a manner similar to the fluctuations of a rigid body in a tug-of-war (TOW) game. This method, called ‘TOW dynamics’, exhibits higher efficiency than conventional reinforcement learning algorithms. We show analytical calculations that validate statistical reasons for TOW dynamics to produce the high performance despite its simplicity. These results imply that various physical systems in which some conservation law holds can be used to implement an efficient ‘decision-making object’. The proposed scheme will provide a new perspective to open up a physics-based analog computing paradigm and to understanding the biological information-processing principles that exploit their underlying physics.

Physics-based approach to color image enhancement in poor visibility conditions.

PubMed

Tan, K K; Oakley, J P

2001-10-01

Degradation of images by the atmosphere is a familiar problem. For example, when terrain is imaged from a forward-looking airborne camera, the atmosphere degradation causes a loss in both contrast and color information. Enhancement of such images is a difficult task because of the complexity in restoring both the luminance and the chrominance while maintaining good color fidelity. One particular problem is the fact that the level of contrast loss depends strongly on wavelength. A novel method is presented for the enhancement of color images. This method is based on the underlying physics of the degradation process, and the parameters required for enhancement are estimated from the image itself.

Beam Dynamics Considerations in Electron Ion Colliders

NASA Astrophysics Data System (ADS)

Krafft, Geoffrey

2015-04-01

The nuclear physics community is converging on the idea that the next large project after FRIB should be an electron-ion collider. Both Brookhaven National Lab and Thomas Jefferson National Accelerator Facility have developed accelerator designs, both of which need novel solutions to accelerator physics problems. In this talk we discuss some of the problems that must be solved and their solutions. Examples in novel beam optics systems, beam cooling, and beam polarization control will be presented. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

Computational studies of thermal and quantum phase transitions approached through non-equilibrium quenching

NASA Astrophysics Data System (ADS)

Liu, Cheng-Wei

Phase transitions and their associated critical phenomena are of fundamental importance and play a crucial role in the development of statistical physics for both classical and quantum systems. Phase transitions embody diverse aspects of physics and also have numerous applications outside physics, e.g., in chemistry, biology, and combinatorial optimization problems in computer science. Many problems can be reduced to a system consisting of a large number of interacting agents, which under some circumstances (e.g., changes of external parameters) exhibit collective behavior; this type of scenario also underlies phase transitions. The theoretical understanding of equilibrium phase transitions was put on a solid footing with the establishment of the renormalization group. In contrast, non-equilibrium phase transition are relatively less understood and currently a very active research topic. One important milestone here is the Kibble-Zurek (KZ) mechanism, which provides a useful framework for describing a system with a transition point approached through a non-equilibrium quench process. I developed two efficient Monte Carlo techniques for studying phase transitions, one is for classical phase transition and the other is for quantum phase transitions, both are under the framework of KZ scaling. For classical phase transition, I develop a non-equilibrium quench (NEQ) simulation that can completely avoid the critical slowing down problem. For quantum phase transitions, I develop a new algorithm, named quasi-adiabatic quantum Monte Carlo (QAQMC) algorithm for studying quantum quenches. I demonstrate the utility of QAQMC quantum Ising model and obtain high-precision results at the transition point, in particular showing generalized dynamic scaling in the quantum system. To further extend the methods, I study more complex systems such as spin-glasses and random graphs. The techniques allow us to investigate the problems efficiently. From the classical perspective, using the NEQ approach I verify the universality class of the 3D Ising spin-glasses. I also investigate the random 3-regular graphs in terms of both classical and quantum phase transitions. I demonstrate that under this simulation scheme, one can extract information associated with the classical and quantum spin-glass transitions without any knowledge prior to the simulation.

It's About Time Physical Disabilities Came Out in the Open: Part I. Amputation, Monoplegia, Hemiplegia, Triplegia, Quadruplegia, Paraplegia.

ERIC Educational Resources Information Center

Davis, Kay

After a definition of the term, mobility impairments, and a discussion of the causes and problems associated with amputation, this document covers, under the major section, Paralysis, six handicapping conditions in terms of how each may affect a student's ability to be successful in both a vocational program and a job. Topics under this section…

Councils of Urgent Studies

ERIC Educational Resources Information Center

Cellarius, Richard A.; Platt, John

1972-01-01

Discusses the role of national or international coordinating councils in focusing research on solutions of major human problems. Presents a taxonomy of 25 areas under the major heading: Physical Technology and Engineering; Biotechnology; Behavior and Personal Relations; National Social Structures; World Structure; and Channels of Effectiveness.…

42 CFR 68.14 - Under what circumstances can the service or payment obligation be canceled, waived, or suspended?

Code of Federal Regulations, 2014 CFR

2014-10-01

... the participant has problems of a personal nature, such as a physical or mental disability or terminal illness in the immediate family, which so intrude on the participant's present and future ability to...

42 CFR 68.14 - Under what circumstances can the service or payment obligation be canceled, waived, or suspended?

Code of Federal Regulations, 2013 CFR

2013-10-01

... the participant has problems of a personal nature, such as a physical or mental disability or terminal illness in the immediate family, which so intrude on the participant's present and future ability to...

Three Years of Global Positioning System Experience on International Space Station

NASA Technical Reports Server (NTRS)

Gomez, Susan

2005-01-01

The International Space Station global positioning systems (GPS) receiver was activated in April 2002. Since that time, numerous software anomalies surfaced that had to be worked around. Some of the software problems required waivers, such as the time function, while others required extensive operator intervention, such as numerous power cycles. Eventually, enough anomalies surfaced that the three pieces of code included in the GPS unit have been re-written and the GPS units were upgraded. The technical aspects of the problems are discussed, as well as the underlying causes that led to the delivery of a product that has had numerous problems. The technical aspects of the problems included physical phenomena that were not well understood, such as the affect that the ionosphere would have on the GPS measurements. The underlying causes were traced to inappropriate use of legacy software, changing requirements, inadequate software processes, unrealistic schedules, incorrect contract type, and unclear ownership responsibilities.

Three Years of Global Positioning System Experience on International Space Station

NASA Technical Reports Server (NTRS)

Gomez, Susan

2006-01-01

The International Space Station global positioning system (GPS) receiver was activated in April 2002. Since that time, numerous software anomalies surfaced that had to be worked around. Some of the software problems required waivers, such as the time function, while others required extensive operator intervention, such as numerous power cycles. Eventually enough anomalies surfaced that the three pieces of code included in the GPS unit have been re-written and the GPS units upgraded. The technical aspects of the problems are discussed, as well as the underlying causes that led to the delivery of a product that has had so many problems. The technical aspects of the problems included physical phenomena that were not well understood, such as the affect that the ionosphere would have on the GPS measurements. The underlying causes were traced to inappropriate use of legacy software, changing requirements, inadequate software processes, unrealistic schedules, incorrect contract type, and unclear ownership responsibilities..

Women in Physics in Latin America: why so few in leadership positions?

NASA Astrophysics Data System (ADS)

Barbosa, Marcia

2008-04-01

Women are greatly under-represented in physics in Latin America. Among all sciences, physics is the field where the increase in the number of women has been particularly slow. Because of this imbalance, many bright young people do not receive the opportunity to learn about physics and to prepare themselves for a physics career, and others are discouraged from doing so. However, the problems is not only that girls are not attracted to go to physics, they few ones that decide to follow the career find difficulties in funding and in promotions. We show that women in Latin America leave physics disproportionately with each step of career advance. Moreover, we also show that in many cases the promotion process exclude women with the same abilities of men. But, why should we care about this problem? Why should women be in physics after all? Women that have a passion for physics should be able to make a living and have a successful career in this field. But, the need of gender balance in science, it is not only a equal opportunity issue. Physics need a greater participation of female researchers in order to survive. Science is changing and it is becoming more interdisciplinary. This evolution is only possible through diversity of thought and of strategies to approach problems. Therefore, excluding women more than limiting the available pool of talented people to half of humanity, we are limiting diversity. Finally, in a society where technology is becoming quite important and is governing our everyday life and where women are highly involved in the educational process, exposing women to science generates a more scientific literate public. We show that the implementation of a few affirmative action strategies bring more balance to the promotion process.

Developmental association of prosocial behaviour with aggression, anxiety and depression from infancy to preadolescence.

PubMed

Nantel-Vivier, Amélie; Pihl, Robert O; Côté, Sylvana; Tremblay, Richard E

2014-10-01

Research on associations between children's prosocial behaviour and mental health has provided mixed evidence. The present study sought to describe and predict the joint development of prosocial behaviour with externalizing and internalizing problems (physical aggression, anxiety and depression) from 2 to 11 years of age. Data were drawn from the National Longitudinal Survey of Children and Youth (NLSCY). Biennial prosocial behaviour, physical aggression, anxiety and depression maternal ratings were sought for 10,700 children aged 0 to 9 years at the first assessment point. While a negative association was observed between prosociality and physical aggression, more complex associations emerged with internalizing problems. Being a boy decreased the likelihood of membership in the high prosocial trajectory. Maternal depression increased the likelihood of moderate aggression, but also of joint high prosociality/low aggression. Low family income predicted the joint development of high prosociality with high physical aggression and high depression. Individual differences exist in the association of prosocial behaviour with mental health. While high prosociality tends to co-occur with low levels of mental health problems, high prosociality and internalizing/externalizing problems can co-occur in subgroups of children. Child, mother and family characteristics are predictive of individual differences in prosocial behaviour and mental health development. Mechanisms underlying these associations warrant future investigations. © 2014 The Authors. Journal of Child Psychology and Psychiatry. © 2014 Association for Child and Adolescent Mental Health.

Liquid mercury sound velocity measurements under high pressure and high temperature by picosecond acoustics in a diamond anvils cell

NASA Astrophysics Data System (ADS)

Decremps, F.; Belliard, L.; Couzinet, B.; Vincent, S.; Munsch, P.; Le Marchand, G.; Perrin, B.

2009-07-01

Recent improvements to measure ultrasonic sound velocities of liquids under extreme conditions are described. Principle and feasibility of picosecond acoustics in liquids embedded in a diamond anvils cell are given. To illustrate the capability of these advances in the sound velocity measurement technique, original high pressure and high temperature results on the sound velocity of liquid mercury up to 5 GPa and 575 K are given. This high pressure technique will certainly be useful in several fundamental and applied problems in physics and many other fields such as geophysics, nonlinear acoustics, underwater sound, petrology or physical acoustics.

The concerns of patients under palliative care and a heart failure clinic are not being met.

PubMed

Anderson, H; Ward, C; Eardley, A; Gomm, S A; Connolly, M; Coppinger, T; Corgie, D; Williams, J L; Makin, W P

2001-07-01

Patients with a terminal illness, identified by palliative care teams working in Manchester, and patients attending a heart failure clinic, were asked to participate in a prospective survey to determine their main concerns. Data were collected from 213 palliative care (PC) patients (mostly with cancer) and 66 patients with heart failure (HF). The median ages of the two patient groups were similar, but the HF patients were more likely to be male and living with a partner; 13% of PC and 7% of HF patients reported that they had no carer. The PC patients had more district nurse, hospice, social work and physiotherapy input. The most frequently reported troublesome problems for PC patients were pain (49%), loss of independence (30%) and difficulty walking (27%). HF patients reported dyspnoea (55%), angina (32%) and tiredness (27%) as the most troublesome problems. From a checklist of symptoms, the frequency of tiredness (PC = 77%, HF = 82%) and difficulty getting about (PC = 71%, HF = 65%) were high in each group. Psychological problems were reported by 61% of PC and 41% of HF patients. Cardiac patients reported more breathlessness and cough than PC patients (83% vs 49% and 44% vs 26%, respectively). Reduced libido was more common in cardiac patients (42% vs 21%). Patient disclosure of troublesome problems to professional carers was high (>87% in both PC and HF patients). Documented action was greater for physical than social or psychological problems. For PC patients, documented action was recorded for 83% physical, 43% social/functional and 52% psychological problems. For HF patients documented action was recorded for 74% cardiac, 60% physical - non-cardiac, 30% social/functional and 28% psychological problems. Clearly many patients' troublesome problems were not being addressed. As a result of this study, specific action by health care professionals was taken in 50% of PC patients and 71% of HF patients. We plan to target specific educational events on the treatment of physical problems, psychological assessment and social service provision.

Can microbes economically remove sulfur

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

Fox, J.L.

Researchers have reported that refiners who now rely on costly physic-chemical procedures to desulfurize petroleum will soon have an alternative microbial-enzyme-based approach to this process. This new approach is still under development and considerable number chemical engineering problems need to be solved before this process is ready for large-scale use. This paper reviews the several research projects dedicated solving the problems that keep a biotechnology-based alternative from competing with chemical desulfurization.

Size Distributions of Solar Proton Events: Methodological and Physical Restrictions

NASA Astrophysics Data System (ADS)

Miroshnichenko, L. I.; Yanke, V. G.

2016-12-01

Based on the new catalogue of solar proton events (SPEs) for the period of 1997 - 2009 (Solar Cycle 23) we revisit the long-studied problem of the event-size distributions in the context of those constructed for other solar-flare parameters. Recent results on the problem of size distributions of solar flares and proton events are briefly reviewed. Even a cursory acquaintance with this research field reveals a rather mixed and controversial picture. We concentrate on three main issues: i) SPE size distribution for {>} 10 MeV protons in Solar Cycle 23; ii) size distribution of {>} 1 GV proton events in 1942 - 2014; iii) variations of annual numbers for {>} 10 MeV proton events on long time scales (1955 - 2015). Different results are critically compared; most of the studies in this field are shown to suffer from vastly different input datasets as well as from insufficient knowledge of underlying physical processes in the SPEs under consideration. New studies in this field should be made on more distinct physical and methodological bases. It is important to note the evident similarity in size distributions of solar flares and superflares in Sun-like stars.

New Approach to Analyzing Physics Problems: A Taxonomy of Introductory Physics Problems

ERIC Educational Resources Information Center

Teodorescu, Raluca E.; Bennhold, Cornelius; Feldman, Gerald; Medsker, Larry

2013-01-01

This paper describes research on a classification of physics problems in the context of introductory physics courses. This classification, called the Taxonomy of Introductory Physics Problems (TIPP), relates physics problems to the cognitive processes required to solve them. TIPP was created in order to design educational objectives, to develop…

Academic Failure in Secondary School: The Inter-Related Role of Health Problems and Educational Context.

PubMed

Needham, Belinda L; Crosnoe, Robert; Muller, Chandra

2004-01-01

This study explores whether the interplay of health problems and school environment predicts academic failure, an individual event with consequences for the life course, as well as for society at large. This exploration proceeds in three steps: 1) we examine whether physical and mental health problems are an academic risk factor during secondary school; 2) we investigate the academic mechanisms underlying this risk status; and 3) we explore whether this risk status varies by school context. A series of logistic regressions reveals that self-rated health and emotional distress are both associated with greater likelihood of failing one or more classes in the next year and that absenteeism, trouble with homework, and student-teacher bonding account for much of these associations. Associations of physical and mental health problems with academic failure vary only slightly across schools, however. We discuss the implications of these findings for both research and policy and argue that the examination of overlap among different domains of adolescent functioning can advance the sociological understanding of health, education, and social problems in general.

42 CFR 68c.13 - Under what circumstances can the service or payment obligation be canceled, waived, or suspended?

Code of Federal Regulations, 2010 CFR

2010-10-01

... future financial resources and obligations; and (3) The extent to which the participant has problems of a personal nature, such as a physical or mental disability or terminal illness in the immediate family, which...

42 CFR 68c.13 - Under what circumstances can the service or payment obligation be canceled, waived, or suspended?

Code of Federal Regulations, 2011 CFR

2011-10-01

... future financial resources and obligations; and (3) The extent to which the participant has problems of a personal nature, such as a physical or mental disability or terminal illness in the immediate family, which...

Big Jobs: Planning for Competence

ERIC Educational Resources Information Center

Jones, Nancy P.

2005-01-01

Three- to five-year-olds grow emotionally participating in meaningful and challenging physical, social, and problem-solving activities outdoors in an early childhood program on a farm. Caring for animals, planting, raking, shoveling, and engaging in meaningful indoor activities, under adult supervision, children learn to work collaboratively,…

Numberical Solution to Transient Heat Flow Problems

ERIC Educational Resources Information Center

Kobiske, Ronald A.; Hock, Jeffrey L.

1973-01-01

Discusses the reduction of the one- and three-dimensional diffusion equation to the difference equation and its stability, convergence, and heat-flow applications under different boundary conditions. Indicates the usefulness of this presentation for beginning students of physics and engineering as well as college teachers. (CC)

“Musculoskeletal problem”: Its prevalence among Iranian dentists

PubMed Central

Nokhostin, Mohammad Reza; Zafarmand, A. Hamid

2016-01-01

Objectives: Musculoskeletal problems (MSPs) are a major complication for practitioners in the field of dentistry. The present study is designed to define the prevalence of MSPs among Iranian dentists. Materials and Methods: This was a cross-sectional survey conducted on 600 dentists. The questions were about demographic characteristics, headache, and physical problems of different parts of the body. Data were analyzed using logistic regression analysis. Results: Of all dentists studied, 67.5% had physical problems. These MSPs were observed in neck (51.87%), wrist (92.96%), waist (11.11%), and shoulder (7.40%) of the practitioners. Some practitioners took leave of absence (18.52%), while others (7.40%) underwent medical care. There was a direct correlation between age (P = 0.0001), high body mass index (BMI; P = 0.021), total number of daily under-care patients (P = 0.002), and little physical activity (P = 0.0001) with MSPs. Conclusion: The prevalence of MSPs is very high among dentists. Awareness about preventive care is necessary for dentists. The dental curriculum also should address ergonomic issues for dental educators. PMID:27195226

A novel approach to piecewise analytic agricultural machinery path reconstruction

NASA Astrophysics Data System (ADS)

Wörz, Sascha; Mederle, Michael; Heizinger, Valentin; Bernhardt, Heinz

2017-12-01

Before analysing machinery operation in fields, it has to be coped with the problem that the GPS signals of GPS receivers located on the machines contain measurement noise, are time-discrete, and the underlying physical system describing the positions, axial and absolute velocities, angular rates and angular orientation of the operating machines during the whole working time are unknown. This research work presents a new three-dimensional mathematical approach using kinematic relations based on control variables as Euler angular velocities and angles and a discrete target control problem, such that the state control function is given by the sum of squared residuals involving the state and control variables to get such a physical system, which yields a noise-free and piecewise analytic representation of the positions, velocities, angular rates and angular orientation. It can be used for a further detailed study and analysis of the problem of why agricultural vehicles operate in practice as they do.

Data-Aware Retrodiction for Asynchronous Harmonic Measurement in a Cyber-Physical Energy System

PubMed Central

Liu, Youda; Wang, Xue; Liu, Yanchi; Cui, Sujin

2016-01-01

Cyber-physical energy systems provide a networked solution for safety, reliability and efficiency problems in smart grids. On the demand side, the secure and trustworthy energy supply requires real-time supervising and online power quality assessing. Harmonics measurement is necessary in power quality evaluation. However, under the large-scale distributed metering architecture, harmonic measurement faces the out-of-sequence measurement (OOSM) problem, which is the result of latencies in sensing or the communication process and brings deviations in data fusion. This paper depicts a distributed measurement network for large-scale asynchronous harmonic analysis and exploits a nonlinear autoregressive model with exogenous inputs (NARX) network to reorder the out-of-sequence measuring data. The NARX network gets the characteristics of the electrical harmonics from practical data rather than the kinematic equations. Thus, the data-aware network approximates the behavior of the practical electrical parameter with real-time data and improves the retrodiction accuracy. Theoretical analysis demonstrates that the data-aware method maintains a reasonable consumption of computing resources. Experiments on a practical testbed of a cyber-physical system are implemented, and harmonic measurement and analysis accuracy are adopted to evaluate the measuring mechanism under a distributed metering network. Results demonstrate an improvement of the harmonics analysis precision and validate the asynchronous measuring method in cyber-physical energy systems. PMID:27548171

Adapting the Euler-Lagrange equation to study one-dimensional motions under the action of a constant force

NASA Astrophysics Data System (ADS)

Dias, Clenilda F.; Araújo, Maria A. S.; Carvalho-Santos, Vagson L.

2018-01-01

The Euler-Lagrange equations (ELE) are very important in the theoretical description of several physical systems. In this work we have used a simplified form of ELE to study one-dimensional motions under the action of a constant force. From the use of the definition of partial derivative, we have proposed two operators, here called mean delta operators, which may be used to solve the ELE in a simplest way. We have applied this simplification to solve three simple mechanical problems in which the particle is under the action of the gravitational field: a free fall body, the Atwood’s machine and the inclined plan. The proposed simplification can be used to introduce the lagrangian formalism in teaching classical mechanics in introductory physics courses.

Fifty moves a year: is there an association between joint physical custody and psychosomatic problems in children?

PubMed

Bergström, Malin; Fransson, Emma; Modin, Bitte; Berlin, Marie; Gustafsson, Per A; Hjern, Anders

2015-08-01

In many Western countries, an increasing number of children with separated parents have joint physical custody, that is, live equally much in their parent's respective homes. In Sweden, joint physical custody is particularly common and concerns between 30% and 40% of the children with separated parents. It has been hypothesised that the frequent moves and lack of stability in parenting may be stressful for these children. We used data from a national classroom survey of all sixth and ninth grade students in Sweden (N=147839) to investigate the association between children's psychosomatic problems and living arrangements. Children in joint physical custody were compared with those living only or mostly with one parent and in nuclear families. We conducted sex-specific linear regression analyses for z-transformed sum scores of psychosomatic problems and adjusted for age, country of origin as well as children's satisfaction with material resources and relationships to parents. Clustering by school was accounted for by using a two-level random intercept model. Children in joint physical custody suffered from less psychosomatic problems than those living mostly or only with one parent but reported more symptoms than those in nuclear families. Satisfaction with their material resources and parent-child relationships was associated with children's psychosomatic health but could not explain the differences between children in the different living arrangements. Children with non-cohabitant parents experience more psychosomatic problems than those in nuclear families. Those in joint physical custody do however report better psychosomatic health than children living mostly or only with one parent. Longitudinal studies with information on family factors before and after the separation are needed to inform policy of children's postseparation living arrangements. 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.

Measuring physical activity in children and adolescents for dietary surveys: practicalities, problems and pitfalls.

PubMed

Mindell, Jennifer S; Coombs, Ngaire; Stamatakis, Emmanuel

2014-05-01

Physical inactivity is an important risk factor for many chronic diseases and contributes to obesity and poor mental well-being. The present paper describes the main advantages and disadvantages, practical problems, suggested uses, and future developments regarding self-reported and objective data collection in the context of dietary surveys. In dietary surveys, physical activity is measured primarily to estimate energy expenditure. Energy expenditure surveillance is important for tracking changes over time, particularly given the debates over the role of the relative importance of energy intake and expenditure changes in the aetiology of obesity. It is also important to assess the extent of underreporting of dietary intake in these surveys. Physical activity data collected should include details on the frequency, duration and relative intensity of activity for each activity type that contributes considerably to overall activity and energy expenditure. Problems of validity and reliability, associated with inaccurate assessment, recall bias, and social desirability bias, are well-known; children under 10 years cannot report their activities accurately. However, despite such limitations, questionnaires are still the dominant method of physical activity assessment in dietary surveys due to their low cost and relatively low participant burden. Objective, time-stamped measures that monitor heart rate and/or movement can provide more comprehensive, quantitative assessment of physical activity but at greater cost and participant burden. Although overcoming many limitations of questionnaires, objective measures also have drawbacks, including technical, practical and interpretational issues.

Physical activity problem-solving inventory for adolescents: Development and initial validation

USDA-ARS?s Scientific Manuscript database

Youth encounter physical activity barriers, often called problems. The purpose of problem-solving is to generate solutions to overcome the barriers. Enhancing problem-solving ability may enable youth to be more physically active. Therefore, a method for reliably assessing physical activity problem-s...

Secure Fusion Estimation for Bandwidth Constrained Cyber-Physical Systems Under Replay Attacks.

PubMed

Chen, Bo; Ho, Daniel W C; Hu, Guoqiang; Yu, Li; Bo Chen; Ho, Daniel W C; Guoqiang Hu; Li Yu; Chen, Bo; Ho, Daniel W C; Hu, Guoqiang; Yu, Li

2018-06-01

State estimation plays an essential role in the monitoring and supervision of cyber-physical systems (CPSs), and its importance has made the security and estimation performance a major concern. In this case, multisensor information fusion estimation (MIFE) provides an attractive alternative to study secure estimation problems because MIFE can potentially improve estimation accuracy and enhance reliability and robustness against attacks. From the perspective of the defender, the secure distributed Kalman fusion estimation problem is investigated in this paper for a class of CPSs under replay attacks, where each local estimate obtained by the sink node is transmitted to a remote fusion center through bandwidth constrained communication channels. A new mathematical model with compensation strategy is proposed to characterize the replay attacks and bandwidth constrains, and then a recursive distributed Kalman fusion estimator (DKFE) is designed in the linear minimum variance sense. According to different communication frameworks, two classes of data compression and compensation algorithms are developed such that the DKFEs can achieve the desired performance. Several attack-dependent and bandwidth-dependent conditions are derived such that the DKFEs are secure under replay attacks. An illustrative example is given to demonstrate the effectiveness of the proposed methods.

[Physical treatment modalities for chronic leg ulcers].

PubMed

Dissemond, J

2010-05-01

An increasing numbers of physical treatment options are available for chronic leg ulcer. In this review article, compression therapy, therapeutic ultrasound, negative pressure therapy, extracorporeal shock wave therapy, electrostimulation therapy, electromagnetic therapy, photodynamic therapy, water-filtered infrared-A-radiation and hydrotherapy are discussed in terms of their practical applications and the underlying evidence. With the exception of compression therapy for most of these treatments, good scientific data are not available. However this is a widespread problem in the treatment of chronic wounds. Nevertheless, several of the described methods such as negative pressure therapy represent one of the gold standards in practical treatment of patients with chronic leg ulcers. Although the use of physical treatment modalities may improve healing in patients with chronic leg ulcers, the diagnosis and treatment of the underlying causes are essential for long-lasting success.

An Object-Oriented Network-Centric Software Architecture for Physical Computing

NASA Astrophysics Data System (ADS)

Palmer, Richard

1997-08-01

Recent developments in object-oriented computer languages and infrastructure such as the Internet, Web browsers, and the like provide an opportunity to define a more productive computational environment for scientific programming that is based more closely on the underlying mathematics describing physics than traditional programming languages such as FORTRAN or C++. In this talk I describe an object-oriented software architecture for representing physical problems that includes classes for such common mathematical objects as geometry, boundary conditions, partial differential and integral equations, discretization and numerical solution methods, etc. In practice, a scientific program written using this architecture looks remarkably like the mathematics used to understand the problem, is typically an order of magnitude smaller than traditional FORTRAN or C++ codes, and hence easier to understand, debug, describe, etc. All objects in this architecture are ``network-enabled,'' which means that components of a software solution to a physical problem can be transparently loaded from anywhere on the Internet or other global network. The architecture is expressed as an ``API,'' or application programmers interface specification, with reference embeddings in Java, Python, and C++. A C++ class library for an early version of this API has been implemented for machines ranging from PC's to the IBM SP2, meaning that phidentical codes run on all architectures.

Perpetual American vanilla option pricing under single regime change risk: an exhaustive study

NASA Astrophysics Data System (ADS)

Montero, Miquel

2009-07-01

Perpetual American options are financial instruments that can be readily exercised and do not mature. In this paper we study in detail the problem of pricing this kind of derivatives, for the most popular flavour, within a framework in which some of the properties—volatility and dividend policy—of the underlying stock can change at a random instant of time but in such a way that we can forecast their final values. Under this assumption we can model actual market conditions because most relevant facts usually entail sharp predictable consequences. The effect of this potential risk on perpetual American vanilla options is remarkable: the very equation that will determine the fair price depends on the solution to be found. Sound results are found under the optics both of finance and physics. In particular, a parallelism among the overall outcome of this problem and a phase transition is established.

Assessing students' ability to solve introductory physics problems using integrals in symbolic and graphical representations

NASA Astrophysics Data System (ADS)

Khan, Neelam; Hu, Dehui; Nguyen, Dong-Hai; Rebello, N. Sanjay

2012-02-01

Integration is widely used in physics in electricity and magnetism (E&M), as well as in mechanics, to calculate physical quantities from other non-constant quantities. We designed a survey to assess students' ability to apply integration to physics problems in introductory physics. Each student was given a set of eight problems, and each set of problems had two different versions; one consisted of symbolic problems and the other graphical problems. The purpose of this study was to investigate students' strategies for solving physics problems that use integrals in first and second-semester calculus-based physics. Our results indicate that most students had difficulty even recognizing that an integral is needed to solve the problem.

Vectorization and parallelization of the finite strip method for dynamic Mindlin plate problems

NASA Technical Reports Server (NTRS)

Chen, Hsin-Chu; He, Ai-Fang

1993-01-01

The finite strip method is a semi-analytical finite element process which allows for a discrete analysis of certain types of physical problems by discretizing the domain of the problem into finite strips. This method decomposes a single large problem into m smaller independent subproblems when m harmonic functions are employed, thus yielding natural parallelism at a very high level. In this paper we address vectorization and parallelization strategies for the dynamic analysis of simply-supported Mindlin plate bending problems and show how to prevent potential conflicts in memory access during the assemblage process. The vector and parallel implementations of this method and the performance results of a test problem under scalar, vector, and vector-concurrent execution modes on the Alliant FX/80 are also presented.

The electrobrachistochrone

NASA Astrophysics Data System (ADS)

Lipscombe, Trevor C.; Mungan, Carl E.

2018-05-01

The brachistochrone problem consists of finding the track of shortest travel time between given initial and final points for a particle sliding frictionlessly along it under the influence of a given external force field. Solvable variations of the standard example of a uniform gravitational field would be suitable for homework and computer projects by undergraduate physics students studying intermediate mechanics and electromagnetism. An electrobrachistochrone problem is here proposed, in which a charged particle moves along a frictionless track under the influence of its electrostatic force of attraction to an image charge in a grounded conducting plane below the track. The path of least time is found to be a foreshortened cycloid and its properties are investigated analytically and graphically.

The Contractual Nature of a Driver's License.

ERIC Educational Resources Information Center

Sariola, Sakari

1989-01-01

Calls for programed administrative change which would reflect concern not only with skills and aptitudes of individual drivers, and with their physical and mental condition, but also with drivers in responsible and enlightened partnership under mutual agreement with society. Presents contractual obligation as one step in solving problem of…

Instruction Using Experiments in a Computer. Final Report.

ERIC Educational Resources Information Center

Fulton, John P.; Hazeltine, Barrett

Included are four computer programs which simulate experiments suitable for freshman engineering and physics courses. The subjects of the programs are ballistic trajectories, variable mass systems, trajectory of a particle under various forces, and design of an electronic emplifier. The report includes the problem statement, its objectives, the…

Multi-Parameter Linear Least-Squares Fitting to Poisson Data One Count at a Time

NASA Technical Reports Server (NTRS)

Wheaton, W.; Dunklee, A.; Jacobson, A.; Ling, J.; Mahoney, W.; Radocinski, R.

1993-01-01

A standard problem in gamma-ray astronomy data analysis is the decomposition of a set of observed counts, described by Poisson statistics, according to a given multi-component linear model, with underlying physical count rates or fluxes which are to be estimated from the data.

Minicomputers in the Teaching Laboratory - An Example from Physics.

ERIC Educational Resources Information Center

Farr, John E.; van den Berg, Willem H.

Microcomputers are commonly interfaced to external devices in scientific, industrial, and consumer settings for data acquisition and for control. The general problem under consideration is the task of taking measurements of some continuous phenomenon, transforming them into digital form, and storing the data in the microcomputer for later use.…

APPLYING OPERATIONAL ANALYSIS TO URBAN EDUCATIONAL SYSTEMS, A WORKING PAPER.

ERIC Educational Resources Information Center

SISSON, ROGER L.

OPERATIONS RESEARCH CONCEPTS ARE POTENTIALLY USEFUL FOR STUDY OF SUCH LARGE URBAN SCHOOL DISTRICT PROBLEMS AS INFORMATION FLOW, PHYSICAL STRUCTURE OF THE DISTRICT, ADMINISTRATIVE DECISION MAKING BOARD POLICY FUNCTIONS, AND THE BUDGET STRUCTURE. OPERATIONAL ANALYSIS REQUIRES (1) IDENTIFICATION OF THE SYSTEM UNDER STUDY, (2) IDENTIFICATION OF…

Under Lock and Key: Preventing Campus Theft of Electronic Equipment.

ERIC Educational Resources Information Center

Harrison, J. Phil

1996-01-01

A discussion of computer theft prevention on college campuses looks at a variety of elements in electronic equipment security, including the extent of the problem, physical antitheft products, computerized access, control of key access, alarm systems, competent security personnel, lighting, use of layers of protection, and increasing…

Attracting Girls into Physics (abstract)

NASA Astrophysics Data System (ADS)

Gadalla, Afaf

2009-04-01

A recent international study of women in physics showed that enrollment in physics and science is declining for both males and females and that women are severely underrepresented in careers requiring a strong physics background. The gender gap begins early in the pipeline, from the first grade. Girls are treated differently than boys at home and in society in ways that often hinder their chances for success. They have fewer freedoms, are discouraged from accessing resources or being adventurous, have far less exposure to problem solving, and are not encouraged to choose their lives. In order to motivate more girl students to study physics in the Assiut governorate of Egypt, the Assiut Alliance for the Women and Assiut Education District collaborated in renovating the education of physics in middle and secondary school classrooms. A program that helps in increasing the number of girls in science and physics has been designed in which informal groupings are organized at middle and secondary schools to involve girls in the training and experiences needed to attract and encourage girls to learn physics. During implementation of the program at some schools, girls, because they had not been trained in problem-solving as boys, appeared not to be as facile in abstracting the ideas of physics, and that was the primary reason for girls dropping out of science and physics. This could be overcome by holding a topical physics and technology summer school under the supervision of the Assiut Alliance for the Women.

Changes in multifractal properties for stable angina pectoris

NASA Astrophysics Data System (ADS)

Knežević, Andrea; Martinis, Mladen; Krstačić, Goran; Vargović, Emil

2005-12-01

The multifractal approach has been applied to temporal fluctuations of heartbeat (RR) intervals, measured in various regimes of physical activity (ergometric data), taken from healthy subjects and those having stable angina pectoris (SAP). The problem we address here is whether SAP changes multifractality observed in healthy subjects. The G-moment method is used to analyse the multifractal spectrum. It is observed that both sets of data characterize multifractality, but a different trend in multifractal behaviour is found for SAP disease, under pronounced physical activity.

Existence of ``free will'' as a problem of physics

NASA Astrophysics Data System (ADS)

Peres, Asher

1986-06-01

The proof of Bell's inequality is based on the assumption that distant observers can freely and independently choose their experiments. As Bell's inequality is experimentally violated, it appears that distant physical systems may behave as a single, nonlocal, indivisible entity. This apparent contradiction is resolved. It is shown that the “free will” assumption is, under usual circumstances, an excellent approximation. I have set before you life and death, blessing and cursing: therefore choose life.... — Deuteronomy XXX, 19

Proceedings for the ICASE Workshop on Heterogeneous Boundary Conditions

NASA Technical Reports Server (NTRS)

Perkins, A. Louise; Scroggs, Jeffrey S.

1991-01-01

Domain Decomposition is a complex problem with many interesting aspects. The choice of decomposition can be made based on many different criteria, and the choice of interface of internal boundary conditions are numerous. The various regions under study may have different dynamical balances, indicating that different physical processes are dominating the flow in these regions. This conference was called in recognition of the need to more clearly define the nature of these complex problems. This proceedings is a collection of the presentations and the discussion groups.

Deep Learning Fluid Mechanics

NASA Astrophysics Data System (ADS)

Barati Farimani, Amir; Gomes, Joseph; Pande, Vijay

2017-11-01

We have developed a new data-driven model paradigm for the rapid inference and solution of the constitutive equations of fluid mechanic by deep learning models. Using generative adversarial networks (GAN), we train models for the direct generation of solutions to steady state heat conduction and incompressible fluid flow without knowledge of the underlying governing equations. Rather than using artificial neural networks to approximate the solution of the constitutive equations, GANs can directly generate the solutions to these equations conditional upon an arbitrary set of boundary conditions. Both models predict temperature, velocity and pressure fields with great test accuracy (>99.5%). The application of our framework for inferring and generating the solutions of partial differential equations can be applied to any physical phenomena and can be used to learn directly from experiments where the underlying physical model is complex or unknown. We also have shown that our framework can be used to couple multiple physics simultaneously, making it amenable to tackle multi-physics problems.

Self-Regulation in the Midst of Complexity: A Case Study of High School Physics Students Engaged in Ill-Structured Problem Solving

NASA Astrophysics Data System (ADS)

Milbourne, Jeffrey David

The purpose of this dissertation study was to explore the experiences of high school physics students who were solving complex, ill-structured problems, in an effort to better understand how self-regulatory behavior mediated the project experience. Consistent with Voss, Green, Post, and Penner's (1983) conception of an ill-structured problem in the natural sciences, the 'problems' consisted of scientific research projects that students completed under the supervision of a faculty mentor. Zimmerman and Campillo's (2003) self-regulatory framework of problem solving provided a holistic guide to data collection and analysis of this multi-case study, with five individual student cases. The study's results are explored in two manuscripts, each targeting a different audience. The first manuscript, intended for the Science Education Research community, presents a thick, rich description of the students' project experiences, consistent with a qualitative, case study analysis. Findings suggest that intrinsic interest was an important self-regulatory factor that helped motivate students throughout their project work, and that the self-regulatory cycle of forethought, performance monitoring, and self-reflection was an important component of the problem-solving process. Findings also support the application of Zimmerman and Campillo's framework to complex, ill-structured problems, particularly the cyclical nature of the framework. Finally, this study suggests that scientific research projects, with the appropriate support, can be a mechanism for improving students' selfregulatory behavior. The second manuscript, intended for Physics practitioners, combines the findings of the first manuscript with the perspectives of the primary, on-site research mentor, who has over a decade's worth of experience mentoring students doing physics research. His experience suggests that a successful research experience requires certain characteristics, including: a slow, 'on-ramp' to the research experience, space to experience productive failure, and an opportunity to enjoy the work they are doing.

Pre-Service Physics Teachers’ Problem-solving Skills in Projectile Motion Concept

NASA Astrophysics Data System (ADS)

Sutarno, S.; Setiawan, A.; Kaniawati, I.; Suhandi, A.

2017-09-01

This study is a preliminary research aiming at exploring pre-service physics teachers’ skills in applying the stage of problem-solving strategies. A total of 76 students of physics education study program at a college in Bengkulu Indonesia participated in the study. The skills on solving physics problems are being explored through exercises that demand the use of problem-solving strategies with several stages such as useful description, physics approach, specific application of physics, physics equation, mathematical procedures, and logical progression. Based on the results of data analysis, it is found that the pre-service physics teachers’ skills are in the moderate category for physics approach and mathematical procedural, and low category for the others. It was concluded that the pre-service physics teachers’ problem-solving skills are categorized low. It is caused by the learning of physics that has done less to practice problem-solving skills. The problems provided are only routine and poorly trained in the implementation of problem-solving strategies.The results of the research can be used as a reference for the importance of the development of physics learning based on higher order thinking skills.

The influence of mastery on mother's health in middle years: Moderating role of stressful life context.

PubMed

King, Victoria; Wickrama, K A S; Klopack, Erick; Lorenz, Frederick O

2018-06-07

Using data from 416 middle-aged mothers gathered over the course of a decade, this study examined the influence of mastery trajectories (the initial level and change), on change in physical health. Mastery is defined as one's ability to control and influence his/her life and environment to reach a desired outcome or goal. Both the initial level and change in mastery from 1991 to 1994 were associated with decreased physical health problems over the middle years (1991-2001). Contextual moderation of this association by stressful life contexts including negative life events and work-family conflict was investigated. Moderation analysis showed that under conditions of low contextual life stressors, the level and increase in mastery significantly contributed to decreases in physical health problems in middle-aged mothers. Alternatively, conditions of high contextual life stressors inhibited the ability of mastery to influence physical health of mothers, suggesting that the positive health impact of mastery on physical health is mitigated by stressful life experiences. Implications for the need to maintain important personal resources, such as mastery, during times of stress are discussed. Copyright © 2018 John Wiley & Sons, Ltd.

A Gradient-Based Multistart Algorithm for Multimodal Aerodynamic Shape Optimization Problems Based on Free-Form Deformation

NASA Astrophysics Data System (ADS)

Streuber, Gregg Mitchell

Environmental and economic factors motivate the pursuit of more fuel-efficient aircraft designs. Aerodynamic shape optimization is a powerful tool in this effort, but is hampered by the presence of multimodality in many design spaces. Gradient-based multistart optimization uses a sampling algorithm and multiple parallel optimizations to reliably apply fast gradient-based optimization to moderately multimodal problems. Ensuring that the sampled geometries remain physically realizable requires manually developing specialized linear constraints for each class of problem. Utilizing free-form deformation geometry control allows these linear constraints to be written in a geometry-independent fashion, greatly easing the process of applying the algorithm to new problems. This algorithm was used to assess the presence of multimodality when optimizing a wing in subsonic and transonic flows, under inviscid and viscous conditions, and a blended wing-body under transonic, viscous conditions. Multimodality was present in every wing case, while the blended wing-body was found to be generally unimodal.

Developmental Biology and Regenerative Medicine: Addressing the Vexing Problem of Persistent Muscle Atrophy in the Chronically Torn Human Rotator Cuff.

PubMed

Meyer, Gretchen A; Ward, Samuel R

2016-05-01

Persistent muscle atrophy in the chronically torn rotator cuff is a significant obstacle for treatment and recovery. Large atrophic changes are predictive of poor surgical and nonsurgical outcomes and frequently fail to resolve even following functional restoration of loading and rehabilitation. New insights into the processes of muscle atrophy and recovery gained through studies in developmental biology combined with the novel tools and strategies emerging in regenerative medicine provide new avenues to combat the vexing problem of muscle atrophy in the rotator cuff. Moving these treatment strategies forward likely will involve the combination of surgery, biologic/cellular agents, and physical interventions, as increasing experimental evidence points to the beneficial interaction between biologic therapies and physiologic stresses. Thus, the physical therapy profession is poised to play a significant role in defining the success of these combinatorial therapies. This perspective article will provide an overview of the developmental biology and regenerative medicine strategies currently under investigation to combat muscle atrophy and how they may integrate into the current and future practice of physical therapy. © 2016 American Physical Therapy Association.

Collection of solved problems in physics

NASA Astrophysics Data System (ADS)

Koupilová, ZdeÅka; Mandíková, Dana; Snětinová, Marie

2017-01-01

To solve physics problems is a key ability which students should reach during their physics education. Ten years ago we started to develop a Collection of fully solved problems. The structure of problems' solutions is specially designed to substitute tutor's help during lesson and encourage students to solve at least some parts of a problem independently. Nowadays the database contains about 770 fully solved problems in physics in Czech, more than 100 problems in Polish and more than 140 problems in English. Other problems are still being translated. Except for physics problems, the Collection has also a mathematical part, which contains more than 300 fully solved problems in mathematics. This paper follows the presentation of the Collection of solved problems from previous years and introduces a new interface of the Collection, its enhanced functionality, new topics, newly created interface for teachers, user feedback and plans for future development. The database is placed at the website of the Department of Physics Education, Faculty of Mathematics and Physics, Charles University in Prague, the links are: http://reseneulohy.cz/fyzika (Czech version); http://www.physicstasks.eu/ (English version).

Lattice QCD Calculations in Nuclear Physics towards the Exascale

NASA Astrophysics Data System (ADS)

Joo, Balint

2017-01-01

The combination of algorithmic advances and new highly parallel computing architectures are enabling lattice QCD calculations to tackle ever more complex problems in nuclear physics. In this talk I will review some computational challenges that are encountered in large scale cold nuclear physics campaigns such as those in hadron spectroscopy calculations. I will discuss progress in addressing these with algorithmic improvements such as multi-grid solvers and software for recent hardware architectures such as GPUs and Intel Xeon Phi, Knights Landing. Finally, I will highlight some current topics for research and development as we head towards the Exascale era This material is funded by the U.S. Department of Energy, Office Of Science, Offices of Nuclear Physics, High Energy Physics and Advanced Scientific Computing Research, as well as the Office of Nuclear Physics under contract DE-AC05-06OR23177.

Scale relativity: from quantum mechanics to chaotic dynamics.

NASA Astrophysics Data System (ADS)

Nottale, L.

Scale relativity is a new approach to the problem of the origin of fundamental scales and of scaling laws in physics, which consists in generalizing Einstein's principle of relativity to the case of scale transformations of resolutions. We recall here how it leads one to the concept of fractal space-time, and to introduce a new complex time derivative operator which allows to recover the Schrödinger equation, then to generalize it. In high energy quantum physics, it leads to the introduction of a Lorentzian renormalization group, in which the Planck length is reinterpreted as a lowest, unpassable scale, invariant under dilatations. These methods are successively applied to two problems: in quantum mechanics, that of the mass spectrum of elementary particles; in chaotic dynamics, that of the distribution of planets in the Solar System.

Role of Various Entropies in the Black Hole Information Loss Problem

NASA Astrophysics Data System (ADS)

Nieuwenhuizen, Th. M.; Volovich, I. V.

2007-09-01

We discuss the current status of the black hole information loss paradox and propose a plan for its solution based on analogies with solid state physics and the irreversibility problem. In a recent paper Hawking has argued that there is no information loss in black holes in asymptotically AdS spacetimes. We remind that there are several types of information (entropy) in statistical physics - fine grained (microscopic) and coarse grained (macroscopic) ones which behave differently under unitary evolution. We suggest that the coarse grained information of the rest of the Universe is lost while fine grained information is preserved. A possibility to develop in quantum gravity an analogue of the Bogoliubov derivation of the irreversible Boltzmann and Navier - Stokes equations from the reversible mechanical equations is discussed.

Deterministic physical systems under uncertain initial conditions: the case of maximum entropy applied to projectile motion

NASA Astrophysics Data System (ADS)

Montecinos, Alejandra; Davis, Sergio; Peralta, Joaquín

2018-07-01

The kinematics and dynamics of deterministic physical systems have been a foundation of our understanding of the world since Galileo and Newton. For real systems, however, uncertainty is largely present via external forces such as friction or lack of precise knowledge about the initial conditions of the system. In this work we focus on the latter case and describe the use of inference methodologies in solving the statistical properties of classical systems subject to uncertain initial conditions. In particular we describe the application of the formalism of maximum entropy (MaxEnt) inference to the problem of projectile motion, given information about the average horizontal range over many realizations. By using MaxEnt we can invert the problem and use the provided information on the average range to reduce the original uncertainty in the initial conditions. Also, additional insight into the initial condition's probabilities, and the projectile path distribution itself, can be achieved based on the value of the average horizontal range. The wide applicability of this procedure, as well as its ease of use, reveals a useful tool with which to revisit a large number of physics problems, from classrooms to frontier research.

Inversion of geophysical potential field data using the finite element method

NASA Astrophysics Data System (ADS)

Lamichhane, Bishnu P.; Gross, Lutz

2017-12-01

The inversion of geophysical potential field data can be formulated as an optimization problem with a constraint in the form of a partial differential equation (PDE). It is common practice, if possible, to provide an analytical solution for the forward problem and to reduce the problem to a finite dimensional optimization problem. In an alternative approach the optimization is applied to the problem and the resulting continuous problem which is defined by a set of coupled PDEs is subsequently solved using a standard PDE discretization method, such as the finite element method (FEM). In this paper, we show that under very mild conditions on the data misfit functional and the forward problem in the three-dimensional space, the continuous optimization problem and its FEM discretization are well-posed including the existence and uniqueness of respective solutions. We provide error estimates for the FEM solution. A main result of the paper is that the FEM spaces used for the forward problem and the Lagrange multiplier need to be identical but can be chosen independently from the FEM space used to represent the unknown physical property. We will demonstrate the convergence of the solution approximations in a numerical example. The second numerical example which investigates the selection of FEM spaces, shows that from the perspective of computational efficiency one should use 2 to 4 times finer mesh for the forward problem in comparison to the mesh of the physical property.

Methods of Mathematical and Computational Physics for Industry, Science, and Technology

NASA Astrophysics Data System (ADS)

Melnik, Roderick V. N.; Voss, Frands

2006-11-01

Many industrial problems provide scientists with important and challenging problems that need to be solved today rather than tomorrow. The key role of mathematical physics, modelling, and computational methodologies in addressing such problems continues to increase. Science has never been exogenous to applied research. Gigantic ships and steam engines, repeating catapult of Dionysius and the Antikythera `computer' invented around 80BC are just a few examples demonstrating a profound link between theoretical and applied science in the ancient world. Nowadays, many industrial problems are typically approached by groups of researchers who are working as a team bringing their expertise to the success of the entire enterprise. Since the late 1960s several groups of European mathematicians and scientists have started organizing regular meetings, seeking new challenges from industry and contributing to the solution of important industrial problems. In particular, this often took the format of week-long workshops originally initiated by the Oxford Study Groups with Industry in 1968. Such workshops are now held in many European countries (typically under the auspices of the European Study Groups with Industry - ESGI), as well as in Australia, Canada, the United States, and other countries around the world. Problems given by industrial partners are sometimes very difficult to complete within a week. However, during a week of brainstorming activities these problems inevitably stimulate developing fruitful new ideas, new approaches, and new collaborations. At the same time, there are cases where as soon as the problem is formulated mathematically, it is relatively easy to solve. Hence, putting the industrial problem into a mathematical framework, based on physical laws, often provides a key element to the success. In addition to this important first step, the value in such cases is the real, practical applicability of the results obtained for an industrial partner who presents the problem. Under both outlined scenarios, scientists and mathematicians are provided with an opportunity to challenge themselves with real-world problems and to work together in a team on important industrial issues. This issue is a result of selected contributions by participants of the meeting that took place in the Sønderborg area of Denmark, one of the most important centers for information technology, telecommunication and electronics in the country. The meeting was hosted by the University of Southern Denmark in a picturesque area of Southern Jutland. It brought together about 65 participants, among whom were professional mathematicians, engineers, physicists, and industrial participants. The meeting was a truly international one, with delegates from four major Danish Universities, the UK, Norway, Italy, Czech Republic, Turkey, China, Germany, Latvia, Canada, the United States, and Finland. Five challenging projects were presented by leading industrial companies, including Grundfos, Danfoss Industrial Control, Unisensor, and Danfoss Flow Division (now Siemens). The meeting featured also the Mathematics for Industry Workshop with several distinguished international speakers. This volume of Journal of Physics: Conference Series on `Methods of Mathematical and Computational Physics for Industry, Science, and Technology' contains contributions from some of the participants of the workshop as well as the papers produced as a result of collaborative efforts with the above mentioned industrial companies. We would like to thank all authors and participants for their contributions and for bearing with us during the review process and preparation of this issue. We thank also all our referees for their timely and detailed reports. The publication of the proceedings of this meeting in Denmark was delayed due to problems with a previous publisher. We are very grateful that Journal of Physics: Conference Series kindly agreed to publish the proceedings rapidly at this late stage. As industrial problems become increasingly multidisciplinary, their successful solutions are often contingent on effective collaborative efforts between scientists, mathematicians, industrialists, and engineers. This volume has provided several examples of such collaborative efforts in the context of real-world industrial problems along with the analysis of important physics-based mathematical models applicable in a range of industrial contexts. Roderick V N Melnik, Professor of Mathematical Modelling, Syddansk Universitet (Denmark) and Professor and Canada Research Chair, Wilfrid Laurier University, Waterloo, Canada E-mail: rmelnik@wlu.ca Frands Voss, Director of the Mads Clausen Institute, Syddansk Universitet (Denmark)

Dynamic inverse models in human-cyber-physical systems

NASA Astrophysics Data System (ADS)

Robinson, Ryan M.; Scobee, Dexter R. R.; Burden, Samuel A.; Sastry, S. Shankar

2016-05-01

Human interaction with the physical world is increasingly mediated by automation. This interaction is characterized by dynamic coupling between robotic (i.e. cyber) and neuromechanical (i.e. human) decision-making agents. Guaranteeing performance of such human-cyber-physical systems will require predictive mathematical models of this dynamic coupling. Toward this end, we propose a rapprochement between robotics and neuromechanics premised on the existence of internal forward and inverse models in the human agent. We hypothesize that, in tele-robotic applications of interest, a human operator learns to invert automation dynamics, directly translating from desired task to required control input. By formulating the model inversion problem in the context of a tracking task for a nonlinear control system in control-a_ne form, we derive criteria for exponential tracking and show that the resulting dynamic inverse model generally renders a portion of the physical system state (i.e., the internal dynamics) unobservable from the human operator's perspective. Under stability conditions, we show that the human can achieve exponential tracking without formulating an estimate of the system's state so long as they possess an accurate model of the system's dynamics. These theoretical results are illustrated using a planar quadrotor example. We then demonstrate that the automation can intervene to improve performance of the tracking task by solving an optimal control problem. Performance is guaranteed to improve under the assumption that the human learns and inverts the dynamic model of the altered system. We conclude with a discussion of practical limitations that may hinder exact dynamic model inversion.

Dannie Heineman Prize for Mathematical Physics: Applying mathematical techniques to solve important problems in quantum theory

NASA Astrophysics Data System (ADS)

Bender, Carl

2017-01-01

The theory of complex variables is extremely useful because it helps to explain the mathematical behavior of functions of a real variable. Complex variable theory also provides insight into the nature of physical theories. For example, it provides a simple and beautiful picture of quantization and it explains the underlying reason for the divergence of perturbation theory. By using complex-variable methods one can generalize conventional Hermitian quantum theories into the complex domain. The result is a new class of parity-time-symmetric (PT-symmetric) theories whose remarkable physical properties have been studied and verified in many recent laboratory experiments.

National health education programs to promote healthy eating and physical activity.

PubMed

Donato, Karen A

2006-02-01

The national education programs and campaigns described here are examples of the many unique kinds of federal efforts under way to promote the pillars of healthy eating and increased physical activity included in the "Healthier US Initiative." They are similar in that: 1) they are based on the best available science that a health problem exists, and 2) that healthy eating and physical active behaviors will improve health status. They are unique in their implementation, for example, in private/public partnerships, coordinating committees of professional associations, and congressionally mandated interventions. Most importantly, they provide the impetus to get a particular health issue on the public agenda.

Physical data measurements and mathematical modelling of simple gas bubble experiments in glass melts

NASA Technical Reports Server (NTRS)

Weinberg, Michael C.

1986-01-01

In this work consideration is given to the problem of the extraction of physical data information from gas bubble dissolution and growth measurements. The discussion is limited to the analysis of the simplest experimental systems consisting of a single, one component gas bubble in a glassmelt. It is observed that if the glassmelt is highly under- (super-) saturated, then surface tension effects may be ignored, simplifying the task of extracting gas diffusivity values from the measurements. If, in addition, the bubble rise velocity is very small (or very large) the ease of obtaining physical property data is enhanced. Illustrations are given for typical cases.

Surveying Turkish High School and University Students' Attitudes and Approaches to Physics Problem Solving

ERIC Educational Resources Information Center

Balta, Nuri; Mason, Andrew J.; Singh, Chandralekha

2016-01-01

Students' attitudes and approaches to physics problem solving can impact how well they learn physics and how successful they are in solving physics problems. Prior research in the U.S. using a validated Attitude and Approaches to Problem Solving (AAPS) survey suggests that there are major differences between students in introductory physics and…

Similarity Theory and Dimensionless Numbers in Heat Transfer

ERIC Educational Resources Information Center

Marin, E.; Calderon, A.; Delgado-Vasallo, O.

2009-01-01

We present basic concepts underlying the so-called similarity theory that in our opinion should be explained in basic undergraduate general physics courses when dealing with heat transport problems, in particular with those involving natural or free convection. A simple example is described that can be useful in showing a criterion for neglecting…

Student Perceptions regarding Vocational High School Teachers' Problem Solving Methods against Undesired Behaviors in Classroom Management

ERIC Educational Resources Information Center

Gulcan, Murat Gurkan

2010-01-01

Teachers' classroom management approach varies depending on several factors such as the social, psychological, cultural and educational status of the student, classroom level, the physical conditions of the school, organization structure. There are different approaches in classroom management. These approaches are gathered under three headings in…

Participation in Science and Technology: Young People's Achievement-Related Choices in Late-Modern Societies

ERIC Educational Resources Information Center

Boe, Maria Vetleseter; Henriksen, Ellen Karoline; Lyons, Terry; Schreiner, Camilla

2011-01-01

Young people's participation in science, technology, engineering and mathematics (STEM) is a matter of international concern. Studies and careers that require physical sciences and advanced mathematics are most affected by the problem and women in particular are under-represented in many STEM fields. This article views international research about…

The Role of Probability in Developing Learners' Models of Simulation Approaches to Inference

ERIC Educational Resources Information Center

Lee, Hollylynne S.; Doerr, Helen M.; Tran, Dung; Lovett, Jennifer N.

2016-01-01

Repeated sampling approaches to inference that rely on simulations have recently gained prominence in statistics education, and probabilistic concepts are at the core of this approach. In this approach, learners need to develop a mapping among the problem situation, a physical enactment, computer representations, and the underlying randomization…

Culture, Identity, and Structure in Social Exchange: A Web-Based Trust Experiment in the United States and Japan

ERIC Educational Resources Information Center

Kuwabara, Ko; Willer, Robb; Macy, Michael W.; Mashima, Rie; Terai, Shigeru; Yamagishi, Toshio

2007-01-01

Cross-cultural trust and cooperation are important concerns for international markets, political cooperation, and cultural exchange. Until recently, this problem was difficult to study under controlled conditions due to the inability to conduct experiments involving interaction between participants located in physically distant locations. We…

Age, Physical Activity, Physical Fitness, Body Composition, and Incidence of Orthopedic Problems.

ERIC Educational Resources Information Center

Research Quarterly for Exercise and Sport, 1989

1989-01-01

Effects of age, physical activity, physical fitness, and body mass index (BMI) on the occurrence of orthopedic problems were examined. For men, physical fitness, BMI, and physical activity were associated with orthopedic problems; for women, physical activity was the main predictor. Age was not a factor for either gender. (JD)

Biological and artificial cognition: what can we learn about mechanisms by modelling physical cognition problems using artificial intelligence planning techniques?

PubMed Central

Chappell, Jackie; Hawes, Nick

2012-01-01

Do we fully understand the structure of the problems we present to our subjects in experiments on animal cognition, and the information required to solve them? While we currently have a good understanding of the behavioural and neurobiological mechanisms underlying associative learning processes, we understand much less about the mechanisms underlying more complex forms of cognition in animals. In this study, we present a proposal for a new way of thinking about animal cognition experiments. We describe a process in which a physical cognition task domain can be decomposed into its component parts, and models constructed to represent both the causal events of the domain and the information available to the agent. We then implement a simple set of models, using the planning language MAPL within the MAPSIM simulation environment, and applying it to a puzzle tube task previously presented to orangutans. We discuss the results of the models and compare them with the results from the experiments with orangutans, describing the advantages of this approach, and the ways in which it could be extended. PMID:22927571

Cyber-Physical Trade-Offs in Distributed Detection Networks

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

Rao, Nageswara S; Yao, David K. Y.; Chin, J. C.

2010-01-01

We consider a network of sensors that measure the scalar intensity due to the background or a source combined with background, inside a two-dimensional monitoring area. The sensor measurements may be random due to the underlying nature of the source and background or due to sensor errors or both. The detection problem is infer the presence of a source of unknown intensity and location based on sensor measurements. In the conventional approach, detection decisions are made at the individual sensors, which are then combined at the fusion center, for example using the majority rule. With increased communication and computation costs,more » we show that a more complex fusion algorithm based on measurements achieves better detection performance under smooth and non-smooth source intensity functions, Lipschitz conditions on probability ratios and a minimum packing number for the state-space. We show that these conditions for trade-offs between the cyber costs and physical detection performance are applicable for two detection problems: (i) point radiation sources amidst background radiation, and (ii) sources and background with Gaussian distributions.« less

Biological and artificial cognition: what can we learn about mechanisms by modelling physical cognition problems using artificial intelligence planning techniques?

PubMed

Chappell, Jackie; Hawes, Nick

2012-10-05

Do we fully understand the structure of the problems we present to our subjects in experiments on animal cognition, and the information required to solve them? While we currently have a good understanding of the behavioural and neurobiological mechanisms underlying associative learning processes, we understand much less about the mechanisms underlying more complex forms of cognition in animals. In this study, we present a proposal for a new way of thinking about animal cognition experiments. We describe a process in which a physical cognition task domain can be decomposed into its component parts, and models constructed to represent both the causal events of the domain and the information available to the agent. We then implement a simple set of models, using the planning language MAPL within the MAPSIM simulation environment, and applying it to a puzzle tube task previously presented to orangutans. We discuss the results of the models and compare them with the results from the experiments with orangutans, describing the advantages of this approach, and the ways in which it could be extended.

Delaunay-based derivative-free optimization for efficient minimization of time-averaged statistics of turbulent flows

NASA Astrophysics Data System (ADS)

Beyhaghi, Pooriya

2016-11-01

This work considers the problem of the efficient minimization of the infinite time average of a stationary ergodic process in the space of a handful of independent parameters which affect it. Problems of this class, derived from physical or numerical experiments which are sometimes expensive to perform, are ubiquitous in turbulence research. In such problems, any given function evaluation, determined with finite sampling, is associated with a quantifiable amount of uncertainty, which may be reduced via additional sampling. This work proposes the first algorithm of this type. Our algorithm remarkably reduces the overall cost of the optimization process for problems of this class. Further, under certain well-defined conditions, rigorous proof of convergence is established to the global minimum of the problem considered.

Advances in electron kinetics and theory of gas discharges

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

Kolobov, Vladimir I.; The University of Alabama in Huntsville, Huntsville, Alabama 35899

2013-10-15

“Electrons, like people, are fertile and infertile: high-energy electrons are fertile and able to reproduce.”—Lev TsendinModern physics of gas discharges increasingly uses physical kinetics for analysis of non-equilibrium plasmas. The description of underlying physics at the kinetic level appears to be important for plasma applications in modern technologies. In this paper, we attempt to grasp the legacy of Professor Lev Tsendin, who advocated the use of the kinetic approach for understanding fundamental problems of gas discharges. We outline the fundamentals of electron kinetics in low-temperature plasmas, describe elements of the modern kinetic theory of gas discharges, and show examples ofmore » the theoretical approach to gas discharge problems used by Lev Tsendin. Important connections between electron kinetics in gas discharges and semiconductors are also discussed. Using several examples, we illustrate how Tsendin's ideas and methods are currently being developed for the implementation of next generation computational tools for adaptive kinetic-fluid simulations of gas discharges used in modern technologies.« less

Selective attention to facial emotion in physically abused children.

PubMed

Pollak, Seth D; Tolley-Schell, Stephanie A

2003-08-01

The ability to allocate attention to emotional cues in the environment is an important feature of adaptive self-regulation. Existing data suggest that physically abused children overattend to angry expressions, but the attentional mechanisms underlying such behavior are unknown. The authors tested 8-11-year-old physically abused children to determine whether they displayed specific information-processing problems in a selective attention paradigm using emotional faces as cues. Physically abused children demonstrated delayed disengagement when angry faces served as invalid cues. Abused children also demonstrated increased attentional benefits on valid angry trials. Results are discussed in terms of the influence of early adverse experience on children's selective attention to threat-related signals as a mechanism in the development of psychopathology.

A sequential solution for anisotropic total variation image denoising with interval constraints

NASA Astrophysics Data System (ADS)

Xu, Jingyan; Noo, Frédéric

2017-09-01

We show that two problems involving the anisotropic total variation (TV) and interval constraints on the unknown variables admit, under some conditions, a simple sequential solution. Problem 1 is a constrained TV penalized image denoising problem; problem 2 is a constrained fused lasso signal approximator. The sequential solution entails finding first the solution to the unconstrained problem, and then applying a thresholding to satisfy the constraints. If the interval constraints are uniform, this sequential solution solves problem 1. If the interval constraints furthermore contain zero, the sequential solution solves problem 2. Here uniform interval constraints refer to all unknowns being constrained to the same interval. A typical example of application is image denoising in x-ray CT, where the image intensities are non-negative as they physically represent linear attenuation coefficient in the patient body. Our results are simple yet seem unknown; we establish them using the Karush-Kuhn-Tucker conditions for constrained convex optimization.

Childspacing intervals and abortion among blacks and whites: a brief report.

PubMed

Russo, N F; Horn, J D; Tromp, S

1993-01-01

Although physical, psychological, and social problems for children born to women denied abortion have been identified, little attention has been paid to the role that close childspacing might play in contributing to those problems. Small childspacing intervals (less than two years) have been linked to numerous physical, psychological, and social problems for mother and child. Using secondary analysis, this study examines the characteristics of 596 mothers who sought abortions in 1987 by race and age. Nearly 25% of these mothers had at least one child under two years of age. Abortion patients with such young children were more likely to be Black and have low incomes than abortion patients with older children. More than half of the mothers studied had more than two children. The findings suggest that a substantial number of children born to women denied access to abortion would be closely spaced, with the resulting adverse health consequences falling more heavily on subpopulations of abortion patients already at higher risk for negative perinatal and neonatal outcomes.

Prevention for elderly people: demand-oriented or problem-oriented?

PubMed

Kupper, Nicolette M; Schreurs, Hanneke; Ten Klooster, Peter M; Bode, Christina; van Ameijden, Erik J C

2011-09-01

To examine the association between self-expressed information needs and corresponding observed health and lifestyle issues in elderly people. Data were used from the 2006 community health survey in Utrecht, a medium-sized city in the Netherlands. Data of 1634 people aged 55 years and older were available for analyses (response 64%). Multivariate logistic regression analyses were used to examine possible associations between expressed information needs and variables on demographics, lifestyle risk behaviours, physical and psychosocial health. Several significant associations were found between information needs and corresponding health and lifestyle problems. However, the explanatory power of the observed problems was generally low, explaining only 7% of the informational needs on lifestyle, and 17% and 28% of the informational needs on physical and psychosocial health, respectively. The findings suggest that prevention amongst the elderly should not be solely based on information needs, but also on observed lifestyle and health. Implications for the use of different approaches of prevention and behavioural models underlying interventions are discussed. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

The Implementation of Physics Problem Solving Strategy Combined with Concept Map in General Physics Course

NASA Astrophysics Data System (ADS)

Hidayati, H.; Ramli, R.

2018-04-01

This paper aims to provide a description of the implementation of Physic Problem Solving strategy combined with concept maps in General Physics learning at Department of Physics, Universitas Negeri Padang. Action research has been conducted in two cycles where each end of the cycle is reflected and improved for the next cycle. Implementation of Physics Problem Solving strategy combined with concept map can increase student activity in solving general physics problem with an average increase of 15% and can improve student learning outcomes from 42,7 in the cycle I become 62,7 in cycle II in general physics at the Universitas Negeri Padang. In the future, the implementation of Physic Problem Solving strategy combined with concept maps will need to be considered in Physics courses.

How can we improve problem solving in undergraduate biology? Applying lessons from 30 years of physics education research.

PubMed

Hoskinson, A-M; Caballero, M D; Knight, J K

2013-06-01

If students are to successfully grapple with authentic, complex biological problems as scientists and citizens, they need practice solving such problems during their undergraduate years. Physics education researchers have investigated student problem solving for the past three decades. Although physics and biology problems differ in structure and content, the instructional purposes align closely: explaining patterns and processes in the natural world and making predictions about physical and biological systems. In this paper, we discuss how research-supported approaches developed by physics education researchers can be adopted by biologists to enhance student problem-solving skills. First, we compare the problems that biology students are typically asked to solve with authentic, complex problems. We then describe the development of research-validated physics curricula emphasizing process skills in problem solving. We show that solving authentic, complex biology problems requires many of the same skills that practicing physicists and biologists use in representing problems, seeking relationships, making predictions, and verifying or checking solutions. We assert that acquiring these skills can help biology students become competent problem solvers. Finally, we propose how biology scholars can apply lessons from physics education in their classrooms and inspire new studies in biology education research.

WE-D-303-00: Computational Phantoms

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

Lewis, John; Brigham and Women’s Hospital and Dana-Farber Cancer Institute, Boston, MA

2015-06-15

Modern medical physics deals with complex problems such as 4D radiation therapy and imaging quality optimization. Such problems involve a large number of radiological parameters, and anatomical and physiological breathing patterns. A major challenge is how to develop, test, evaluate and compare various new imaging and treatment techniques, which often involves testing over a large range of radiological parameters as well as varying patient anatomies and motions. It would be extremely challenging, if not impossible, both ethically and practically, to test every combination of parameters and every task on every type of patient under clinical conditions. Computer-based simulation using computationalmore » phantoms offers a practical technique with which to evaluate, optimize, and compare imaging technologies and methods. Within simulation, the computerized phantom provides a virtual model of the patient’s anatomy and physiology. Imaging data can be generated from it as if it was a live patient using accurate models of the physics of the imaging and treatment process. With sophisticated simulation algorithms, it is possible to perform virtual experiments entirely on the computer. By serving as virtual patients, computational phantoms hold great promise in solving some of the most complex problems in modern medical physics. In this proposed symposium, we will present the history and recent developments of computational phantom models, share experiences in their application to advanced imaging and radiation applications, and discuss their promises and limitations. Learning Objectives: Understand the need and requirements of computational phantoms in medical physics research Discuss the developments and applications of computational phantoms Know the promises and limitations of computational phantoms in solving complex problems.« less

Stability of flow of a thermoviscoelastic fluid between rotating coaxial circular cylinders

NASA Technical Reports Server (NTRS)

Ghandour, N. N.; Narasimhan, M. N. L.

1976-01-01

The stability problem of thermoviscoelastic fluid flow between rotating coaxial cylinders is investigated using nonlinear thermoviscoelastic constitutive equations due to Eringen and Koh. The velocity field is found to be identical with that of the classical viscous case and the case of the viscoelastic fluid, but the temperature and pressure fields are found to be different. By imposing some physically reasonable mechanical and geometrical restrictions on the flow, and by a suitable mathematical analysis, the problem is reduced to a characteristic value problem. The resulting problem is solved and stability criteria are obtained in terms of critical Taylor numbers. In general, it is found that thermoviscoelastic fluids are more stable than classical viscous fluids and viscoinelastic fluids under similar conditions.

Dual-aspect monism à la Pauli and Jung perforates the completeness of physics

NASA Astrophysics Data System (ADS)

Atmanspacher, Harald

2012-12-01

In the mid 19th century, the physicist Wolfgang Pauli and the psychologist Carl Gustav Jung developed a philosophical position for the mind-matter problem that is today called dual-aspect monism. They conjectured a picture in which the mental and the material arise as two complementary aspects of one underlying psychophysically neutral reality to which they cannot be reduced and to which direct empirical access is impossible. This picture suggests structural, persistent,re-producible mind-matter correlations by splitting the underlying reality into aspects. In addition, it suggests induced, occasional, evasive mind-matter correlations above and below, respectively, those stable baseline correlations. These correlations, and the way they arise, suggest that the domain of the physical is not completely independent of the domain of the mental, and both are not independent from the assumed reality underlying them. Some ideas are presented of how these relationships might be conceived.

The Effect of Problem Based Learning (PBL) Instruction on Students' Motivation and Problem Solving Skills of Physics

ERIC Educational Resources Information Center

Argaw, Aweke Shishigu; Haile, Beyene Bashu; Ayalew, Beyene Tesfaw; Kuma, Shiferaw Gadisa

2017-01-01

Through the learning of physics, students will acquire problem solving skills which are relevant to their daily life. Determining the best way in which students learn physics takes a priority in physics education. The goal of the present study was to determine the effect of problem based learning strategy on students' problem solving skills and…

Physical health problems among patients seeking treatment for alcohol use disorders: a study in six European cities.

PubMed

Gossop, Michael; Neto, Domingos; Radovanovic, Mirjana; Batra, Anil; Toteva, Sonya; Musalek, Michael; Skutle, Arvid; Goos, Cees

2007-06-01

The present study investigates physical health problems among patients with alcohol use disorders at alcohol treatment agencies in six European cities. The sample comprised 315 patients with a primary alcohol use disorder. Data were collected at admission to treatment using a structured research protocol, and ratings were made by a medically qualified physician subsequent to a physical examination of the patient. Physical health problems were extremely common: 79% of the sample had at least one problem, and 59% had two or more problems. Health problems were often serious, and 60% had at least one health problem that required treatment. The most common problems were gastrointestinal and liver disorders, but about a quarter of the sample had cardiovascular or neurological problems. Frequency of drinking, duration of alcohol use disorder, and severity of alcohol dependence were associated with increased physical morbidity. Current smoking status and age were also associated with poorer physical health. Older drinkers had more physical health problems although they were less severely alcohol dependent than their younger counterparts. The high prevalence of physical health problems among problem drinkers provides opportunities of screening for alcohol use disorders not only in specialist alcohol treatment services but also in other health-care settings. It is recommended that alcohol treatment agencies should provide a full routine health screen of patients at admission to treatment with provision or referral to appropriate treatment.

Perceived problem solving, stress, and health among college students.

PubMed

Largo-Wight, Erin; Peterson, P Michael; Chen, W William

2005-01-01

To study the relationships among perceived problem solving, stress, and physical health. The Perceived Stress Questionnaire (PSQ), Personal Problem solving Inventory (PSI), and a stress-related physical health symptoms checklist were used to measure perceived stress, problem solving, and health among undergraduate college students (N = 232). Perceived problem-solving ability predicted self-reported physical health symptoms (R2 = .12; P < .001) and perceived stress (R2 = .19; P < .001). Perceived problem solving was a stronger predictor of physical health and perceived stress than were physical activity, alcohol consumption, or social support. Implications for college health promotion are discussed.

The Dolphin in the Mirror - A Familiar Face?

NASA Astrophysics Data System (ADS)

Dibble, Dianna Samuelson; Van Alstyne, Kaitlin Katie; Rohr, Jim; Ridgway, Sam

2017-01-01

We suggest how a basic physics problem becomes much richer when researchers of various disciplines converse. Our discussion explores Snell's window from the perspective of what a dolphin might see. An aperture, Snell's window, allows light to travel through the air-water interface. Outside this window, there is total reflection from under the water-air interface. Dolphins see through the aperture to follow our movements above the water's surface. When dolphins look outside the window, can they see their own reflections from under the water-air interface?

Fluid moments of the nonlinear Landau collision operator

DOE PAGES

Hirvijoki, E.; Lingam, M.; Pfefferle, D.; ...

2016-08-09

An important problem in plasma physics is the lack of an accurate and complete description of Coulomb collisions in associated fluid models. To shed light on the problem, this Letter introduces an integral identity involving the multivariate Hermite tensor polynomials and presents a method for computing exact expressions for the fluid moments of the nonlinear Landau collision operator. In conclusion, the proposed methodology provides a systematic and rigorous means of extending the validity of fluid models that have an underlying inverse-square force particle dynamics to arbitrary collisionality and flow.

The interplay of externalizing problems and physical and inductive discipline during childhood.

PubMed

Choe, Daniel Ewon; Olson, Sheryl L; Sameroff, Arnold J

2013-11-01

Children who are physically disciplined are at elevated risk for externalizing problems. Conversely, maternal reasoning and reminding of rules, or inductive discipline, is associated with fewer child externalizing problems. Few studies have simultaneously examined bidirectional associations between these forms of discipline and child adjustment using cross-informant, multimethod data. We hypothesized that less inductive and more physical discipline would predict more externalizing problems, children would have evocative effects on parenting, and high levels of either form of discipline would predict low levels of the other. In a study of 241 children-spanning ages 3, 5.5, and 10-structural equation modeling indicated that 3-year-olds with higher teacher ratings of externalizing problems received higher mother ratings of physical discipline at age 5.5. Mothers endorsing more inductive discipline at child age 3 reported less physical discipline and had children with fewer externalizing problems at age 5.5. Negative bidirectional associations emerged between physical and inductive discipline from ages 5.5 to 10. Findings suggested children's externalizing problems elicited physical discipline, and maternal inductive discipline might help prevent externalizing problems and physical discipline.

Analytical derivation: An epistemic game for solving mathematically based physics problems

NASA Astrophysics Data System (ADS)

Bajracharya, Rabindra R.; Thompson, John R.

2016-06-01

Problem solving, which often involves multiple steps, is an integral part of physics learning and teaching. Using the perspective of the epistemic game, we documented a specific game that is commonly pursued by students while solving mathematically based physics problems: the analytical derivation game. This game involves deriving an equation through symbolic manipulations and routine mathematical operations, usually without any physical interpretation of the processes. This game often creates cognitive obstacles in students, preventing them from using alternative resources or better approaches during problem solving. We conducted hour-long, semi-structured, individual interviews with fourteen introductory physics students. Students were asked to solve four "pseudophysics" problems containing algebraic and graphical representations. The problems required the application of the fundamental theorem of calculus (FTC), which is one of the most frequently used mathematical concepts in physics problem solving. We show that the analytical derivation game is necessary, but not sufficient, to solve mathematically based physics problems, specifically those involving graphical representations.

A Multivariate Model of Physics Problem Solving

ERIC Educational Resources Information Center

Taasoobshirazi, Gita; Farley, John

2013-01-01

A model of expertise in physics problem solving was tested on undergraduate science, physics, and engineering majors enrolled in an introductory-level physics course. Structural equation modeling was used to test hypothesized relationships among variables linked to expertise in physics problem solving including motivation, metacognitive planning,…

Physical activity problem-solving inventory for adolescents: development and initial validation.

PubMed

Thompson, Debbe; Bhatt, Riddhi; Watson, Kathy

2013-08-01

Youth encounter physical activity barriers, often called problems. The purpose of problem solving is to generate solutions to overcome the barriers. Enhancing problem-solving ability may enable youth to be more physically active. Therefore, a method for reliably assessing physical activity problem-solving ability is needed. The purpose of this research was to report the development and initial validation of the physical activity problem-solving inventory for adolescents (PAPSIA). Qualitative and quantitative procedures were used. The social problem-solving inventory for adolescents guided the development of the PAPSIA scale. Youth (14- to 17-year-olds) were recruited using standard procedures, such as distributing flyers in the community and to organizations likely to be attended by adolescents. Cognitive interviews were conducted in person. Adolescents completed pen and paper versions of the questionnaire and/or scales assessing social desirability, self-reported physical activity, and physical activity self-efficacy. An expert panel review, cognitive interviews, and a pilot study (n = 129) established content validity. Construct, concurrent, and predictive validity were also established (n = 520 youth). PAPSIA is a promising measure for assessing youth physical activity problem-solving ability. Future research will assess its validity with objectively measured physical activity.

Marshak Lectureship Talk: Women in Physics in the Baltic States Region: Problems and Solutions

NASA Astrophysics Data System (ADS)

Satkovskiene, Dalia

2008-03-01

In this contribution the gender equality problem in physics will be discussed on the basis of the results obtained implementing the project ``Baltic States Network: Women in Sciences and High Technology'' (BASNET) initiated by Lithuanian women physicists and financed by European Commission. The main goal of BASNET project was creation of the regional Strategy how to deal with women in sciences problem in the Baltic States. It has some stages and the contribution follows them. The first one was in depth sociological study aiming to find out disincentives and barriers women scientists face in their career and work at science and higher education institutions. Analysis of results revealed wide range of problems concerned with science organization, management and financing common for both counterparts. However it also proved the existence of women discrimination in sciences. As main factors influencing women under-representation in Physics was found: the stereotypes existing in the society where physics is assigned to the masculine area of activity; failings of the science management system, where highest positions are distributed not using the institutionalized objective criteria but by voting, where the correctness of majority solutions is anticipated implicitly. In physics where male scientists are the majority (they also usually compose executive boards, committees etc.) results of such a procedures often are unfavorable for women. The same reasons also influence women ``visibility'' in physicist's community and as the consequence possibility to receive needed recourses for their research as well as appropriate presentation of results obtained. The study revealed also the conservatism of scientific community- reluctance to face existing in the scientific society problems and to start solving them. On the basis of the results obtained as well practice of other countries the common strategy of solving women in physics (sciences) in the Baltic States region was formulated. As changing the stereotypes is long lasting process it was decided firstly to concentrate strategy implementation plans on changes in science management policy tackling the problem from the top and allowing receive the most quick results. For this we created the regional Baltic States Network among the corresponding international women working groups, professional organizations (Scientific societies) and corresponding departments of the governmental institutions. BASNET also became a full member of European Platform of Women Scientists (EPWS)-prestige women organization signally influencing the European Community science policy.

Training Undergraduate Physics Peer Tutors

NASA Astrophysics Data System (ADS)

Nossal, S. M.; Jacob, A. T.

2004-05-01

The University of Wisconsin's Physics Peer Mentor Tutor Program matches upper level undergraduate physics students in small study groups with students studying introductory algebra-based physics. We work with students who are potentially at-risk for having academic trouble with the course. They include students with a low exam score, learning disabilities, no high school physics, weak math backgrounds, and/or on academic probation. We also work with students from groups under represented in the sciences and who may be feeling isolated or marginal on campus such as minority, returning adult, and international students. The tutors provide a supportive learning environment, extra practice problems, and an overview of key concepts. In so doing, they help our students to build confidence and problem solving skills applicable to physics and other areas of their academic careers. The Physics Peer Mentor Tutor Program is modeled after a similar program for chemistry created by the University of Wisconsin's Chemistry Learning Center. Both programs are now run in collaboration. The tutors are chosen for their academic strength and excellent communication skills. Our tutors are majoring in physics, math, and secondary-level science education. The tutors receive ongoing training and supervision throughout the year. They attend weekly discipline-specific meetings to discuss strategies for teaching the content currently being discussed in the physics course. They also participate in a weekly teaching seminar with science tutors from chemistry and biochemistry to discuss teaching methods, mentoring, and general information relating to the students with whom we work. We will describe an overview of the Physics Peer Mentor Tutor Program with a focus on the teacher training program for our undergraduate tutors.

Use of model analysis to analyse Thai students’ attitudes and approaches to physics problem solving

NASA Astrophysics Data System (ADS)

Rakkapao, S.; Prasitpong, S.

2018-03-01

This study applies the model analysis technique to explore the distribution of Thai students’ attitudes and approaches to physics problem solving and how those attitudes and approaches change as a result of different experiences in physics learning. We administered the Attitudes and Approaches to Problem Solving (AAPS) survey to over 700 Thai university students from five different levels, namely students entering science, first-year science students, and second-, third- and fourth-year physics students. We found that their inferred mental states were generally mixed. The largest gap between physics experts and all levels of the students was about the role of equations and formulas in physics problem solving, and in views towards difficult problems. Most participants of all levels believed that being able to handle the mathematics is the most important part of physics problem solving. Most students’ views did not change even though they gained experiences in physics learning.

How Can We Improve Problem Solving in Undergraduate Biology? Applying Lessons from 30 Years of Physics Education Research

PubMed Central

Hoskinson, A.-M.; Caballero, M. D.; Knight, J. K.

2013-01-01

If students are to successfully grapple with authentic, complex biological problems as scientists and citizens, they need practice solving such problems during their undergraduate years. Physics education researchers have investigated student problem solving for the past three decades. Although physics and biology problems differ in structure and content, the instructional purposes align closely: explaining patterns and processes in the natural world and making predictions about physical and biological systems. In this paper, we discuss how research-supported approaches developed by physics education researchers can be adopted by biologists to enhance student problem-solving skills. First, we compare the problems that biology students are typically asked to solve with authentic, complex problems. We then describe the development of research-validated physics curricula emphasizing process skills in problem solving. We show that solving authentic, complex biology problems requires many of the same skills that practicing physicists and biologists use in representing problems, seeking relationships, making predictions, and verifying or checking solutions. We assert that acquiring these skills can help biology students become competent problem solvers. Finally, we propose how biology scholars can apply lessons from physics education in their classrooms and inspire new studies in biology education research. PMID:23737623

Rising to a New Paradigm: Infusing Health and Wellness into the Music Curriculum

ERIC Educational Resources Information Center

Pierce, Deborah L.

2012-01-01

Musicians, like athletes, daily face the stark reality of physical and psychological health issues that can negatively affect or end their careers. Research shows compelling reasons for making changes to the value systems and in the educational process under which musicians are trained to help alleviate these problems. Changes would include…

An event-based architecture for solving constraint satisfaction problems

PubMed Central

Mostafa, Hesham; Müller, Lorenz K.; Indiveri, Giacomo

2015-01-01

Constraint satisfaction problems are ubiquitous in many domains. They are typically solved using conventional digital computing architectures that do not reflect the distributed nature of many of these problems, and are thus ill-suited for solving them. Here we present a parallel analogue/digital hardware architecture specifically designed to solve such problems. We cast constraint satisfaction problems as networks of stereotyped nodes that communicate using digital pulses, or events. Each node contains an oscillator implemented using analogue circuits. The non-repeating phase relations among the oscillators drive the exploration of the solution space. We show that this hardware architecture can yield state-of-the-art performance on random SAT problems under reasonable assumptions on the implementation. We present measurements from a prototype electronic chip to demonstrate that a physical implementation of the proposed architecture is robust to practical non-idealities and to validate the theory proposed. PMID:26642827

Problem Solving of Newton's Second Law through a System of Total Mass Motion

ERIC Educational Resources Information Center

Abdullah, Helmi

2014-01-01

Nowadays, many researchers discovered various effective strategies in teaching physics, from traditional to modern strategy. However, research on physics problem solving is still inadequate. Physics problem is an integral part of physics learning and requires strategy to solve it. Besides that, problem solving is the best way to convey principle,…

Epistemic Beliefs about Justification Employed by Physics Students and Faculty in Two Different Problem Contexts

ERIC Educational Resources Information Center

Mercan, Fatih Caglayan

2012-01-01

This study examines the epistemic beliefs about justification employed by physics undergraduate and graduate students and faculty in the context of solving a standard classical physics problem and a frontier physics problem. Data were collected by a think-aloud problem solving session followed by a semi-structured interview conducted with 50…

Inquiry-based problem solving in introductory physics

NASA Astrophysics Data System (ADS)

Koleci, Carolann

What makes problem solving in physics difficult? How do students solve physics problems, and how does this compare to an expert physicist's strategy? Over the past twenty years, physics education research has revealed several differences between novice and expert problem solving. The work of Chi, Feltovich, and Glaser demonstrates that novices tend to categorize problems based on surface features, while experts categorize according to theory, principles, or concepts1. If there are differences between how problems are categorized, then are there differences between how physics problems are solved? Learning more about the problem solving process, including how students like to learn and what is most effective, requires both qualitative and quantitative analysis. In an effort to learn how novices and experts solve introductory electricity problems, a series of in-depth interviews were conducted, transcribed, and analyzed, using both qualitative and quantitative methods. One-way ANOVA tests were performed in order to learn if there are any significant problem solving differences between: (a) novices and experts, (b) genders, (c) students who like to answer questions in class and those who don't, (d) students who like to ask questions in class and those who don't, (e) students employing an interrogative approach to problem solving and those who don't, and (f) those who like physics and those who dislike it. The results of both the qualitative and quantitative methods reveal that inquiry-based problem solving is prevalent among novices and experts, and frequently leads to the correct physics. These findings serve as impetus for the third dimension of this work: the development of Choose Your Own Adventure Physics(c) (CYOAP), an innovative teaching tool in physics which encourages inquiry-based problem solving. 1Chi, M., P. Feltovich, R. Glaser, "Categorization and Representation of Physics Problems by Experts and Novices", Cognitive Science, 5, 121--152 (1981).

Spontaneous collapse: A solution to the measurement problem and a source of the decay in mesonic systems

NASA Astrophysics Data System (ADS)

Simonov, Kyrylo; Hiesmayr, Beatrix C.

2016-11-01

Dynamical reduction models propose a solution to the measurement problem in quantum mechanics: the collapse of the wave function becomes a physical process. We compute the predictions to decaying and flavor-oscillating neutral mesons for the two most promising collapse models, the QMUPL (quantum mechanics with universal position localization) model and the mass-proportional CSL (continuous spontaneous localization) model. Our results are showing (i) a strong sensitivity to the very assumptions of the noise field underlying those two collapse models and (ii) under particular assumptions the CSL case allows one even to recover the decay dynamics. This in turn allows one to predict the effective collapse rates solely based on the measured values for the oscillation (mass differences) and the measured values of the decay constants. The four types of neutral mesons (K meson, D meson, Bd meson, and Bs meson) lead surprisingly to ranges comparable to those put forward by Adler [J. Phys. A: Math. Theor. 40, 2935 (2007), 10.1088/1751-8113/40/12/S03] and Ghirardi, Rimini, and Weber [Phys. Rev. D 34, 470 (1986), 10.1103/PhysRevD.34.470]. Our results show that these systems at high energies are very sensitive to possible modifications of the standard quantum theory, making them a very powerful laboratory to rule out certain collapse scenarios and study the detailed physical processes solving the measurement problem.

A meta-analysis of disparities in childhood sexual abuse, parental physical abuse, and peer victimization among sexual minority and sexual nonminority individuals.

PubMed

Friedman, Mark S; Marshal, Michael P; Guadamuz, Thomas E; Wei, Chongyi; Wong, Carolyn F; Saewyc, Elizabeth; Stall, Ron

2011-08-01

We compared the likelihood of childhood sexual abuse (under age 18), parental physical abuse, and peer victimization based on sexual orientation. We conducted a meta-analysis of adolescent school-based studies that compared the likelihood of childhood abuse among sexual minorities vs sexual nonminorities. Sexual minority individuals were on average 3.8, 1.2, 1.7, and 2.4 times more likely to experience sexual abuse, parental physical abuse, or assault at school or to miss school through fear, respectively. Moderation analysis showed that disparities between sexual minority and sexual nonminority individuals were larger for (1) males than females for sexual abuse, (2) females than males for assault at school, and (3) bisexual than gay and lesbian for both parental physical abuse and missing school through fear. Disparities did not change between the 1990s and the 2000s. The higher rates of abuse experienced by sexual minority youths may be one of the driving mechanisms underlying higher rates of mental health problems, substance use, risky sexual behavior, and HIV reported by sexual minority adults.

Impact of Indoor Physical Environment on Learning Efficiency in Different Types of Tasks: A 3 × 4 × 3 Full Factorial Design Analysis.

PubMed

Xiong, Lilin; Huang, Xiao; Li, Jie; Mao, Peng; Wang, Xiang; Wang, Rubing; Tang, Meng

2018-06-13

Indoor physical environments appear to influence learning efficiency nowadays. For improvement in learning efficiency, environmental scenarios need to be designed when occupants engage in different learning tasks. However, how learning efficiency is affected by indoor physical environment based on task types are still not well understood. The present study aims to explore the impacts of three physical environmental factors (i.e., temperature, noise, and illuminance) on learning efficiency according to different types of tasks, including perception, memory, problem-solving, and attention-oriented tasks. A 3 × 4 × 3 full factorial design experiment was employed in a university classroom with 10 subjects recruited. Environmental scenarios were generated based on different levels of temperature (17 °C, 22 °C, and 27 °C), noise (40 dB(A), 50 dB(A), 60 dB(A), and 70 dB(A)) and illuminance (60 lx, 300 lx, and 2200 lx). Accuracy rate (AC), reaction time (RT), and the final performance indicator (PI) were used to quantify learning efficiency. The results showed ambient temperature, noise, and illuminance exerted significant main effect on learning efficiency based on four task types. Significant concurrent effects of the three factors on final learning efficiency was found in all tasks except problem-solving-oriented task. The optimal environmental scenarios for top learning efficiency were further identified under different environmental interactions. The highest learning efficiency came in thermoneutral, relatively quiet, and bright conditions in perception-oriented task. Subjects performed best under warm, relatively quiet, and moderately light exposure when recalling images in the memory-oriented task. Learning efficiency peaked to maxima in thermoneutral, fairly quiet, and moderately light environment in problem-solving process while in cool, fairly quiet and bright environment with regard to attention-oriented task. The study provides guidance for building users to conduct effective environmental intervention with simultaneous controls of ambient temperature, noise, and illuminance. It contributes to creating the most suitable indoor physical environment for improving occupants learning efficiency according to different task types. The findings could further supplement the present indoor environment-related standards or norms with providing empirical reference on environmental interactions.

Comparison of fundamental physical properties of the model cells (protocells) and the living cells reveals the need in protophysiology

NASA Astrophysics Data System (ADS)

Matveev, V. V.

2017-01-01

A hypothesis is proposed about potassium ponds being the cradles of life enriches the gamut of ideas about the possible conditions of pre-biological evolution on the primeval Earth, but does not bring us closer to solving the real problem of the origin of life. The gist of the matter lies in the mechanism of making a delimitation between two environments - the intracellular environment and the habitat of protocells. Since the sodium-potassium pump (Na+/K+-ATPase) was discovered, no molecular model has been proposed for a predecessor of the modern sodium pump. This has brought into life the idea of the potassium pond, wherein protocells would not need a sodium pump. However, current notions of the operation of living cells come into conflict with even physical laws when trying to use them to explain the origin and functioning of protocells. Thus, habitual explanations of the physical properties of living cells have become inapplicable to explain the corresponding properties of Sidney Fox's microspheres. Likewise, existing approaches to solving the problem of the origin of life do not see the need for the comparative study of living cells and cell models, assemblies of biological and artificial small molecules and macromolecules under physical conditions conducive to the origin of life. The time has come to conduct comprehensive research into the fundamental physical properties of protocells and create a new discipline - protocell physiology or protophysiology - which should bring us much closer to solving the problem of the origin of life.

Shifting College Students' Epistemological Framing Using Hypothetical Debate Problems

ERIC Educational Resources Information Center

Hu, Dehui; Rebello, N. Sanjay

2014-01-01

Developing expertise in physics problem solving requires the ability to use mathematics effectively in physical scenarios. Novices and experts often perceive the use of mathematics in physics differently. Students' perceptions and how they frame the use of mathematics in physics play an important role in their physics problem solving. In this…

Does the central limit theorem always apply to phase noise? Some implications for radar problems

NASA Astrophysics Data System (ADS)

Gray, John E.; Addison, Stephen R.

2017-05-01

The phase noise problem or Rayleigh problem occurs in all aspects of radar. It is an effect that a radar engineer or physicist always has to take into account as part of a design or in attempt to characterize the physics of a problem such as reverberation. Normally, the mathematical difficulties of phase noise characterization are avoided by assuming the phase noise probability distribution function (PDF) is uniformly distributed, and the Central Limit Theorem (CLT) is invoked to argue that the superposition of relatively few random components obey the CLT and hence the superposition can be treated as a normal distribution. By formalizing the characterization of phase noise (see Gray and Alouani) for an individual random variable, the summation of identically distributed random variables is the product of multiple characteristic functions (CF). The product of the CFs for phase noise has a CF that can be analyzed to understand the limitations CLT when applied to phase noise. We mirror Kolmogorov's original proof as discussed in Papoulis to show the CLT can break down for receivers that gather limited amounts of data as well as the circumstances under which it can fail for certain phase noise distributions. We then discuss the consequences of this for matched filter design as well the implications for some physics problems.

A Delay-Aware and Reliable Data Aggregation for Cyber-Physical Sensing

PubMed Central

Zhang, Jinhuan; Long, Jun; Zhang, Chengyuan; Zhao, Guihu

2017-01-01

Physical information sensed by various sensors in a cyber-physical system should be collected for further operation. In many applications, data aggregation should take reliability and delay into consideration. To address these problems, a novel Tiered Structure Routing-based Delay-Aware and Reliable Data Aggregation scheme named TSR-DARDA for spherical physical objects is proposed. By dividing the spherical network constructed by dispersed sensor nodes into circular tiers with specifically designed widths and cells, TSTR-DARDA tries to enable as many nodes as possible to transmit data simultaneously. In order to ensure transmission reliability, lost packets are retransmitted. Moreover, to minimize the latency while maintaining reliability for data collection, in-network aggregation and broadcast techniques are adopted to deal with the transmission between data collecting nodes in the outer layer and their parent data collecting nodes in the inner layer. Thus, the optimization problem is transformed to minimize the delay under reliability constraints by controlling the system parameters. To demonstrate the effectiveness of the proposed scheme, we have conducted extensive theoretical analysis and comparisons to evaluate the performance of TSR-DARDA. The analysis and simulations show that TSR-DARDA leads to lower delay with reliability satisfaction. PMID:28218668

Hidden physics models: Machine learning of nonlinear partial differential equations

NASA Astrophysics Data System (ADS)

Raissi, Maziar; Karniadakis, George Em

2018-03-01

While there is currently a lot of enthusiasm about "big data", useful data is usually "small" and expensive to acquire. In this paper, we present a new paradigm of learning partial differential equations from small data. In particular, we introduce hidden physics models, which are essentially data-efficient learning machines capable of leveraging the underlying laws of physics, expressed by time dependent and nonlinear partial differential equations, to extract patterns from high-dimensional data generated from experiments. The proposed methodology may be applied to the problem of learning, system identification, or data-driven discovery of partial differential equations. Our framework relies on Gaussian processes, a powerful tool for probabilistic inference over functions, that enables us to strike a balance between model complexity and data fitting. The effectiveness of the proposed approach is demonstrated through a variety of canonical problems, spanning a number of scientific domains, including the Navier-Stokes, Schrödinger, Kuramoto-Sivashinsky, and time dependent linear fractional equations. The methodology provides a promising new direction for harnessing the long-standing developments of classical methods in applied mathematics and mathematical physics to design learning machines with the ability to operate in complex domains without requiring large quantities of data.

Superposition Quantification

NASA Astrophysics Data System (ADS)

Chang, Li-Na; Luo, Shun-Long; Sun, Yuan

2017-11-01

The principle of superposition is universal and lies at the heart of quantum theory. Although ever since the inception of quantum mechanics a century ago, superposition has occupied a central and pivotal place, rigorous and systematic studies of the quantification issue have attracted significant interests only in recent years, and many related problems remain to be investigated. In this work we introduce a figure of merit which quantifies superposition from an intuitive and direct perspective, investigate its fundamental properties, connect it to some coherence measures, illustrate it through several examples, and apply it to analyze wave-particle duality. Supported by Science Challenge Project under Grant No. TZ2016002, Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing, Key Laboratory of Random Complex Structures and Data Science, Chinese Academy of Sciences, Grant under No. 2008DP173182

Resistive switching phenomena: A review of statistical physics approaches

DOE PAGES

Lee, Jae Sung; Lee, Shinbuhm; Noh, Tae Won

2015-08-31

Here we report that resistive switching (RS) phenomena are reversible changes in the metastable resistance state induced by external electric fields. After discovery ~50 years ago, RS phenomena have attracted great attention due to their potential application in next-generation electrical devices. Considerable research has been performed to understand the physical mechanisms of RS and explore the feasibility and limits of such devices. There have also been several reviews on RS that attempt to explain the microscopic origins of how regions that were originally insulators can change into conductors. However, little attention has been paid to the most important factor inmore » determining resistance: how conducting local regions are interconnected. Here, we provide an overview of the underlying physics behind connectivity changes in highly conductive regions under an electric field. We first classify RS phenomena according to their characteristic current–voltage curves: unipolar, bipolar, and threshold switchings. Second, we outline the microscopic origins of RS in oxides, focusing on the roles of oxygen vacancies: the effect of concentration, the mechanisms of channel formation and rupture, and the driving forces of oxygen vacancies. Third, we review RS studies from the perspective of statistical physics to understand connectivity change in RS phenomena. We discuss percolation model approaches and the theory for the scaling behaviors of numerous transport properties observed in RS. Fourth, we review various switching-type conversion phenomena in RS: bipolar-unipolar, memory-threshold, figure-of-eight, and counter-figure-of-eight conversions. Finally, we review several related technological issues, such as improvement in high resistance fluctuations, sneak-path problems, and multilevel switching problems.« less

Differences in Visual Attention between Those Who Correctly and Incorrectly Answer Physics Problems

ERIC Educational Resources Information Center

Madsen, Adrian M.; Larson, Adam M.; Loschky, Lester C.; Rebello, N. Sanjay

2012-01-01

This study investigated how visual attention differed between those who correctly versus incorrectly answered introductory physics problems. We recorded eye movements of 24 individuals on six different conceptual physics problems where the necessary information to solve the problem was contained in a diagram. The problems also contained areas…

Dissociative conceptual and quantitative problem solving outcomes across interactive engagement and traditional format introductory physics

NASA Astrophysics Data System (ADS)

McDaniel, Mark A.; Stoen, Siera M.; Frey, Regina F.; Markow, Zachary E.; Hynes, K. Mairin; Zhao, Jiuqing; Cahill, Michael J.

2016-12-01

The existing literature indicates that interactive-engagement (IE) based general physics classes improve conceptual learning relative to more traditional lecture-oriented classrooms. Very little research, however, has examined quantitative problem-solving outcomes from IE based relative to traditional lecture-based physics classes. The present study included both pre- and post-course conceptual-learning assessments and a new quantitative physics problem-solving assessment that included three representative conservation of energy problems from a first-semester calculus-based college physics course. Scores for problem translation, plan coherence, solution execution, and evaluation of solution plausibility were extracted for each problem. Over 450 students in three IE-based sections and two traditional lecture sections taught at the same university during the same semester participated. As expected, the IE-based course produced more robust gains on a Force Concept Inventory than did the lecture course. By contrast, when the full sample was considered, gains in quantitative problem solving were significantly greater for lecture than IE-based physics; when students were matched on pre-test scores, there was still no advantage for IE-based physics on gains in quantitative problem solving. Further, the association between performance on the concept inventory and quantitative problem solving was minimal. These results highlight that improved conceptual understanding does not necessarily support improved quantitative physics problem solving, and that the instructional method appears to have less bearing on gains in quantitative problem solving than does the kinds of problems emphasized in the courses and homework and the overlap of these problems to those on the assessment.

Invisibility problem in acoustics, electromagnetism and heat transfer. Inverse design method

NASA Astrophysics Data System (ADS)

Alekseev, G.; Tokhtina, A.; Soboleva, O.

2017-10-01

Two approaches (direct design and inverse design methods) for solving problems of designing devices providing invisibility of material bodies of detection using different physical fields - electromagnetic, acoustic and static are discussed. The second method is applied for solving problems of designing cloaking devices for the 3D stationary thermal scattering model. Based on this method the design problems under study are reduced to respective control problems. The material parameters (radial and tangential heat conductivities) of the inhomogeneous anisotropic medium filling the thermal cloak and the density of auxiliary heat sources play the role of controls. A unique solvability of direct thermal scattering problem in the Sobolev space is proved and the new estimates of solutions are established. Using these results, the solvability of control problem is proved and the optimality system is derived. Based on analysis of optimality system, the stability estimates of optimal solutions are established and numerical algorithms for solving particular thermal cloaking problem are proposed.

The Interplay of Externalizing Problems and Physical and Inductive Discipline during Childhood

PubMed Central

Choe, Daniel Ewon; Olson, Sheryl L.; Sameroff, Arnold J.

2013-01-01

Children who are physically disciplined are at elevated risk for externalizing problems. Conversely, maternal reasoning and reminding of rules, or inductive discipline, is associated with fewer child externalizing problems. Few studies have simultaneously examined bidirectional associations between these forms of discipline and child adjustment using cross-informant, multi-method data. We hypothesized that less inductive and more physical discipline would predict more externalizing problems, children would have evocative effects on parenting, and high levels of either form of discipline would predict low levels of the other. In a study of 241 children–spanning ages 3, 5.5, and 10–structural equation modeling indicated that 3-year-olds with higher teacher ratings of externalizing problems received higher mother ratings of physical discipline at age 5.5. Mothers endorsing more inductive discipline at child age 3 reported less physical discipline and had children with fewer externalizing problems at age 5.5. Negative bidirectional associations emerged between physical and inductive discipline from ages 5.5 to 10. Findings suggested children’s externalizing problems elicited physical discipline, and maternal inductive discipline might help prevent externalizing problems and physical discipline. PMID:23458660

What Is Physics Problem-Solving Competency? The Views of Arnold Sommerfeld and Enrico Fermi

NASA Astrophysics Data System (ADS)

Niss, Martin

2018-05-01

A central goal of physics education is to teach problem-solving competency, but the description of the nature of this competency is somehwat fragmentary and implicit in the literature. The present article uses recent historical scholarship on Arnold Sommerfeld and Enrico Fermi to identify and characterize two positions on the nature of physics problem-solving competency. The first, Sommerfeld's, is a "theory first, phenomenon second" approach. Here, the relevant problems originate in one of the theories of physics and the goal of the problem-solver is to make a mathematical analysis of the relevant equation(s) and then give a qualitative analysis of the phenomenon that arise from these mathematical results. Fermi's position is a "phenomenon first, theory second" approach, where the starting point is a physical phenomenon that is analyzed and then brought into the realm of a physics theory. The two positions are illustrated with solutions to two problems and it is shown that the two positions are reflected in problem collections of university educations in physics.

Fundamental interactions involving neutrons and neutrinos: reactor-based studies led by Petersburg Nuclear Physics Institute (National Research Centre 'Kurchatov Institute') [PNPI (NRC KI)

NASA Astrophysics Data System (ADS)

Serebrov, A. P.

2015-11-01

Neutrons of very low energy ( ˜ 10-7 eV), commonly known as ultracold, are unique in that they can be stored in material and magnetic traps, thus enhancing methodical opportunities to conduct precision experiments and to probe the fundamentals of physics. One of the central problems of physics, of direct relevance to the formation of the Universe, is the violation of time invariance. Experiments searching for the nonzero neutron electric dipole moment serve as a time invariance test, and the use of ultracold neutrons provides very high measurement precision. Precision neutron lifetime measurements using ultracold neutrons are extremely important for checking ideas on the early formation of the Universe. This paper discusses problems that arise in studies using ultracold neutrons. Also discussed are the currently highly topical problem of sterile neutrinos and the search for reactor antineutrino oscillations at distances of 6-12 meters from the reactor core. The field reviewed is being investigated at multiple facilities globally. The present paper mainly concentrates on the results of PNPI-led studies at WWR-M PNPI (Gatchina), ILL (Grenoble), and SM-3 (Dimitrovgrad) reactors, and also covers the results obtained during preparation for research at the PIK reactor which is under construction.

Generalized Finsler geometric continuum physics with applications in fracture and phase transformations

NASA Astrophysics Data System (ADS)

Clayton, J. D.

2017-02-01

A theory of deformation of continuous media based on concepts from Finsler differential geometry is presented. The general theory accounts for finite deformations, nonlinear elasticity, and changes in internal state of the material, the latter represented by elements of a state vector of generalized Finsler space whose entries consist of one or more order parameter(s). Two descriptive representations of the deformation gradient are considered. The first invokes an additive decomposition and is applied to problems involving localized inelastic deformation mechanisms such as fracture. The second invokes a multiplicative decomposition and is applied to problems involving distributed deformation mechanisms such as phase transformations or twinning. Appropriate free energy functions are posited for each case, and Euler-Lagrange equations of equilibrium are derived. Solutions are obtained for specific problems of tensile fracture of an elastic cylinder and for amorphization of a crystal under spherical and uniaxial compression. The Finsler-based approach is demonstrated to be more general and potentially more physically descriptive than existing hyperelasticity models couched in Riemannian geometry or Euclidean space, without incorporation of supplementary ad hoc equations or spurious fitting parameters. Predictions for single crystals of boron carbide ceramic agree qualitatively, and in many instances quantitatively, with results from physical experiments and atomic simulations involving structural collapse and failure of the crystal along its c-axis.

Mesh refinement and numerical sensitivity analysis for parameter calibration of partial differential equations

NASA Astrophysics Data System (ADS)

Becker, Roland; Vexler, Boris

2005-06-01

We consider the calibration of parameters in physical models described by partial differential equations. This task is formulated as a constrained optimization problem with a cost functional of least squares type using information obtained from measurements. An important issue in the numerical solution of this type of problem is the control of the errors introduced, first, by discretization of the equations describing the physical model, and second, by measurement errors or other perturbations. Our strategy is as follows: we suppose that the user defines an interest functional I, which might depend on both the state variable and the parameters and which represents the goal of the computation. First, we propose an a posteriori error estimator which measures the error with respect to this functional. This error estimator is used in an adaptive algorithm to construct economic meshes by local mesh refinement. The proposed estimator requires the solution of an auxiliary linear equation. Second, we address the question of sensitivity. Applying similar techniques as before, we derive quantities which describe the influence of small changes in the measurements on the value of the interest functional. These numbers, which we call relative condition numbers, give additional information on the problem under consideration. They can be computed by means of the solution of the auxiliary problem determined before. Finally, we demonstrate our approach at hand of a parameter calibration problem for a model flow problem.

WE-D-303-01: Development and Application of Digital Human Phantoms

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

Segars, P.

2015-06-15

Modern medical physics deals with complex problems such as 4D radiation therapy and imaging quality optimization. Such problems involve a large number of radiological parameters, and anatomical and physiological breathing patterns. A major challenge is how to develop, test, evaluate and compare various new imaging and treatment techniques, which often involves testing over a large range of radiological parameters as well as varying patient anatomies and motions. It would be extremely challenging, if not impossible, both ethically and practically, to test every combination of parameters and every task on every type of patient under clinical conditions. Computer-based simulation using computationalmore » phantoms offers a practical technique with which to evaluate, optimize, and compare imaging technologies and methods. Within simulation, the computerized phantom provides a virtual model of the patient’s anatomy and physiology. Imaging data can be generated from it as if it was a live patient using accurate models of the physics of the imaging and treatment process. With sophisticated simulation algorithms, it is possible to perform virtual experiments entirely on the computer. By serving as virtual patients, computational phantoms hold great promise in solving some of the most complex problems in modern medical physics. In this proposed symposium, we will present the history and recent developments of computational phantom models, share experiences in their application to advanced imaging and radiation applications, and discuss their promises and limitations. Learning Objectives: Understand the need and requirements of computational phantoms in medical physics research Discuss the developments and applications of computational phantoms Know the promises and limitations of computational phantoms in solving complex problems.« less

Explaining suicide in an urban slum of Mumbai, India: a sociocultural autopsy.

PubMed

Parkar, Shubhangi R; Nagarsekar, Balkrishna; Weiss, Mitchell G

2009-01-01

Health demographic mortality studies use verbal autopsies to identify suicide as a cause of death. Psychological autopsies focus almost exclusively on associated high-risk psychiatric disorders. New approaches considering contextual factors are needed for preventing suicide and promoting mental health. This study examined explanations of suicide reported by surviving family members or close friends with reference to social, cultural, and environmental conditions as well as the challenges of life in the Malavani slum of Mumbai. An EMIC (Explanatory Model Interview Catalog) interview based on a cultural epidemiological framework considered underlying problems, perceived causes, and sociocultural contexts. It was administered to survivors of 76 people who had died by suicide (56.6% women). Accounts of underlying problems typically referred to various aspects of tension (73.7%). Perceived causes often identified multiple factors. The sociocultural contexts of suicide included the victimization of women, the personal and social impact of problem drinking, marital problems, physical health problems, mental tension, possession and sorcery. Women were particularly vulnerable to the impact of problem drinking by a spouse or father. This study demonstrates the value of an approach to sociocultural autopsy examining local contexts and explanations of suicide. Findings highlight needs for both mental health services and culturally sensitive social interventions.

The Equation of State and Optical Conductivity of Warm Dense He and H2

NASA Astrophysics Data System (ADS)

Brygoo, Stephanie; Eggert, Jon H.; Loubeyre, Paul; McWilliams, Ryan S.; Hicks, Damien G.; Celliers, Peter M.; Boehly, Tom R.; Jeanloz, Raymond; Collins, Gilbert W.

2007-06-01

The determination of the equations of state of helium and hydrogen at very high density is an important problem at the frontier between condensed matter physics and plasma physics with important implications for planetary physics. Due to the limitations of the conventional techniques for reaching extreme densities(static or single shock compression), there are almost no data for the deep interior states of Jupiter. We present here shock compression measurements of helium and hydrogen, precompressed in diamond anvil cells up to 3ρliquid. We report the shock pressure, density and reflectivity up to 2 Mbar for helium and up to 1 Mbar for hydrogen. The data are compared to equations of state models used for astrophysical applications and to recent first principles calculations. This work was performed under the auspices of the U.S. Department of Energy (DOE) by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.

Quantum and semiclassical spin networks: from atomic and molecular physics to quantum computing and gravity

NASA Astrophysics Data System (ADS)

Aquilanti, Vincenzo; Bitencourt, Ana Carla P.; Ferreira, Cristiane da S.; Marzuoli, Annalisa; Ragni, Mirco

2008-11-01

The mathematical apparatus of quantum-mechanical angular momentum (re)coupling, developed originally to describe spectroscopic phenomena in atomic, molecular, optical and nuclear physics, is embedded in modern algebraic settings which emphasize the underlying combinatorial aspects. SU(2) recoupling theory, involving Wigner's 3nj symbols, as well as the related problems of their calculations, general properties, asymptotic limits for large entries, nowadays plays a prominent role also in quantum gravity and quantum computing applications. We refer to the ingredients of this theory—and of its extension to other Lie and quantum groups—by using the collective term of 'spin networks'. Recent progress is recorded about the already established connections with the mathematical theory of discrete orthogonal polynomials (the so-called Askey scheme), providing powerful tools based on asymptotic expansions, which correspond on the physical side to various levels of semi-classical limits. These results are useful not only in theoretical molecular physics but also in motivating algorithms for the computationally demanding problems of molecular dynamics and chemical reaction theory, where large angular momenta are typically involved. As for quantum chemistry, applications of these techniques include selection and classification of complete orthogonal basis sets in atomic and molecular problems, either in configuration space (Sturmian orbitals) or in momentum space. In this paper, we list and discuss some aspects of these developments—such as for instance the hyperquantization algorithm—as well as a few applications to quantum gravity and topology, thus providing evidence of a unifying background structure.

Physics or Fantasy?

ERIC Educational Resources Information Center

Slisko, Josip; Krokhin, Arkady

1995-01-01

Though the field of physics is moving toward more realistic problems and the use of computers and mathematical modeling to promote insightful treatment of physical problems, artificial problems still appear in textbooks in the field of electrostatics. Discusses physical arguments why one of the most popular textbook applications of Coulomb's Law…

Quantum Mechanics - Fundamentals and Applications to Technology

NASA Astrophysics Data System (ADS)

Singh, Jasprit

1996-10-01

Explore the relationship between quantum mechanics and information-age applications This volume takes an altogether unique approach to quantum mechanics. Providing an in-depth exposition of quantum mechanics fundamentals, it shows how these concepts are applied to most of today's information technologies, whether they are electronic devices or materials. No other text makes this critical, essential leap from theory to real-world applications. The book's lively discussion of the mathematics involved fits right in with contemporary multidisciplinary trends in education: Once the basic formulation has been derived in a given chapter, the connection to important technological problems is summarily described. The many helpful features include * Twenty-eight application-oriented sections that focus on lasers, transistors, magnetic memories, superconductors, nuclear magnetic resonance (NMR), and other important technology-driving materials and devices * One hundred solved examples, with an emphasis on numerical results and the connection between the physics and its applications * End-of-chapter problems that ground the student in both fundamental and applied concepts * Numerous figures and tables to clarify the various topics and provide a global view of the problems under discussion * Over two hundred illustrations to highlight problems and text A book for the information age, Quantum Mechanics: Fundamentals and Applications to Technology promises to become a standard in departments of electrical engineering, applied physics, and materials science, as well as physics. It is an excellent text for senior undergraduate and graduate students, and a helpful reference for practicing scientists, engineers, and chemists in the semiconductor and electronic industries.

The Missing Curriculum in Physics Problem-Solving Education

NASA Astrophysics Data System (ADS)

Williams, Mobolaji

2018-05-01

Physics is often seen as an excellent introduction to science because it allows students to learn not only the laws governing the world around them, but also, through the problems students solve, a way of thinking which is conducive to solving problems outside of physics and even outside of science. In this article, we contest this latter idea and argue that in physics classes, students do not learn widely applicable problem-solving skills because physics education almost exclusively requires students to solve well-defined problems rather than the less-defined problems which better model problem solving outside of a formal class. Using personal, constructed, and the historical accounts of Schrödinger's development of the wave equation and Feynman's development of path integrals, we argue that what is missing in problem-solving education is practice in identifying gaps in knowledge and in framing these knowledge gaps as questions of the kind answerable using techniques students have learned. We discuss why these elements are typically not taught as part of the problem-solving curriculum and end with suggestions on how to incorporate these missing elements into physics classes.

Adolescent exposure to violence and adult physical and mental health problems.

PubMed

Franzese, Robert J; Covey, Herbert C; Tucker, Abigail S; McCoy, Leah; Menard, Scott

2014-12-01

Evidence on the relationship of adolescent exposure to violence (AEV) with adult physical and mental health problems is limited, with studies often focusing on earlier childhood rather than adolescence, and also on short term rather than long term outcomes. Information specifically on the relationship of AEV to seeking help for mental health problems in adulthood from either formal sources such as mental health professionals or informal sources such as friends and clergy is even more difficult to find. The present study investigates how adolescent exposure to violence (AEV), in the form of parental physical abuse, witnessing parental violence, and exposure to violence in the neighborhood, are related to self-reported adult physical problems and seeking formal or informal assistance with mental health, controlling for more general adolescent violent victimization and for self-reports and parent reports of mental health problems in adolescence. This study adds to the literature on AEV and adult physical problems, and provides a rare look at the relationship of AEV to adult help-seeking for mental health problems. The results suggest that AEV is associated with mental health problems in adolescence for both females and males, that for females AEV is related to physical problems and to seeking help for mental health problems in adulthood, but for males the only significant relationship involves inconsistent reports of witnessing parental violence and adult physical problems. Copyright © 2014 Elsevier Ltd. All rights reserved.

The interaction of fatigue, physical activity, and health-related quality of life in adults with multiple sclerosis (MS) and cardiovascular disease (CVD).

PubMed

Newland, Pamela K; Lunsford, Valerie; Flach, Alicia

2017-02-01

In addition to the underlying health problems and disability associated with multiple sclerosis (MS) and cardiovascular disease (CVD), adults with each of these chronic illnesses are independently known to experience fatigue. While fatigue's influence on physical activity and health related quality of life (HRQOL) with each of these illnesses has been discussed, what is lacking is information on how fatigue impacts physical activity and health related quality of life, and ultimately self-management for adults with these conditions. Additionally, individuals may be unaware of the significance of maintaining optimal physical activity in order to maintain everyday function and self-management. Thus, the purpose of this article is to discuss the complex effect of fatigue on physical activity and HRQOL among adults with MS and CVD, and to present potential self-management strategies. Copyright © 2016 Elsevier Inc. All rights reserved.

Pre-service teachers' metaphorical perceptions of "physics" as a concept

NASA Astrophysics Data System (ADS)

Aykutlu, Isil; Bayrak, Celal; Bezen, Sevim

2018-02-01

In this study, the aim is to reveal pre-service biology, chemistry and mathematics teachers' metaphorical perceptions for physics. This study was patterned by employing phenomenology, which is one of the qualitative research methods. Sampling of the study consists of 90 pre-service teachers enrolled at the departments of biology, chemistry, and mathematics education at the faculty of education of a state university in Ankara. A metaphor form was prepared to determine pre-service teachers' mental metaphors for the physics concept. Then, it was determined that a total of 80 pre-service teachers generated 34 different metaphors for physics concept. As a result of the study, 34 metaphors generated by pre-service teachers for "physics" concept were gathered under seven different categories. Also, it was determined that pre-service teachers express most frequently "life" (26,25%) and "a difficult to solve problem"(21,25%) which take place in conceptual categories.

Development of a testlet generator in re-engineering the Indonesian physics national-exams

NASA Astrophysics Data System (ADS)

Mindyarto, Budi Naini; Mardapi, Djemari; Bastari

2017-08-01

The Indonesian Physics national-exams are end-of-course summative assessments that could be utilized to support the assessment for learning in physics educations. This paper discusses the development and evaluation of a testlet generator based on a re-engineering of Indonesian physics national exams. The exam problems were dissected and decomposed into testlets revealing the deeper understanding of the underlying physical concepts by inserting a qualitative question and its scientific reasoning question. A template-based generator was built to facilitate teachers in generating testlet variants that would be more conform to students' scientific attitude development than their original simple multiple-choice formats. The testlet generator was built using open source software technologies and was evaluated focusing on the black-box testing by exploring the generator's execution, inputs and outputs. The results showed the correctly-performed functionalities of the developed testlet generator in validating inputs, generating testlet variants, and accommodating polytomous item characteristics.

Underkeel Clearance Study.

DTIC Science & Technology

1981-09-01

EnterewJ N00014-80-C-0395 CONTENTS Page EXECUTIVE SUMMARY 1.0 INTRODUCTION 1.1 The Underlying Problem ................. 1-1 1.2 The Current Study...3-4 3.2.4 CVN Berthinq Facilities .................... 3-4 ii! JI N00014-80-C-0395 CONTENTS (continued) 3.3 Hydrologic Conditions...Drafts ...................... 3-10 3.8.3 Underkeel Clearance ........ .............. 3-10 4.0 THE ANALYSIS 4.1 The Physical Model

Time-Domain Finite Element Analysis of Nonlinear Breakdown Problems in High-Power-Microwave Devices and Systems

DTIC Science & Technology

2015-12-24

simulation of the electromagnetic- plasma interaction and the high-power microwave breakdown in air. Under the high pressure and high frequency condition of...the high-power air breakdown, the physical phenomenon is described using a nonlinearly coupled full-wave Maxwell and fluid plasma system. This...Challenges ........................................................................... 3 3.1.1 Plasma Fluid Model

Development of a new flux splitting scheme

NASA Technical Reports Server (NTRS)

Liou, Meng-Sing; Steffen, Christopher J., Jr.

1991-01-01

The use of a new splitting scheme, the advection upstream splitting method, for model aerodynamic problems where Van Leer and Roe schemes had failed previously is discussed. The present scheme is based on splitting in which the convective and pressure terms are separated and treated differently depending on the underlying physical conditions. The present method is found to be both simple and accurate.

Development of a new flux splitting scheme

NASA Technical Reports Server (NTRS)

Liou, Meng-Sing; Steffen, Christopher J., Jr.

1991-01-01

The successful use of a novel splitting scheme, the advection upstream splitting method, for model aerodynamic problems where Van Leer and Roe schemes had failed previously is discussed. The present scheme is based on splitting in which the convective and pressure terms are separated and treated differently depending on the underlying physical conditions. The present method is found to be both simple and accurate.

The epistemological status of general circulation models

NASA Astrophysics Data System (ADS)

Loehle, Craig

2018-03-01

Forecasts of both likely anthropogenic effects on climate and consequent effects on nature and society are based on large, complex software tools called general circulation models (GCMs). Forecasts generated by GCMs have been used extensively in policy decisions related to climate change. However, the relation between underlying physical theories and results produced by GCMs is unclear. In the case of GCMs, many discretizations and approximations are made, and simulating Earth system processes is far from simple and currently leads to some results with unknown energy balance implications. Statistical testing of GCM forecasts for degree of agreement with data would facilitate assessment of fitness for use. If model results need to be put on an anomaly basis due to model bias, then both visual and quantitative measures of model fit depend strongly on the reference period used for normalization, making testing problematic. Epistemology is here applied to problems of statistical inference during testing, the relationship between the underlying physics and the models, the epistemic meaning of ensemble statistics, problems of spatial and temporal scale, the existence or not of an unforced null for climate fluctuations, the meaning of existing uncertainty estimates, and other issues. Rigorous reasoning entails carefully quantifying levels of uncertainty.

Space radiation research in the new millenium--from where we come and where we go.

PubMed

Kiefer, J

2001-01-01

Space radiation research had a significant impact in the past. The physical interaction of heavy charged particles with living matter and the development of models, including microdosimetry, were stimulated by problems encountered in space. New phenomena were discovered. Advanced dosimetric techniques had to be developed and computational methods to describe the radiation field in space. The understanding of the radiobiology of heavy ions, necessary for a well-founded risk assessment and prompted by space radiation research, constitutes also the basis for heavy ion radiotherapy. So far unknown areas like the interaction of microgravity and radiation were opened. The space station will give even more opportunities. For the first time it will be possible to investigate animals for a longer time under the influence of both microgravity and radiation. Living systems can be exposed under well defined conditions with parallel physical measurements. Solar particle events are still an unsolved problem. Significant improvement in their predictability and quantitative description can be expected. All this will not only give exciting opportunities for research but will also translate into immediate benefit for human beings. This paper will attempt to give an overview of the past achievements and glance into the future.

Student reasoning about graphs in different contexts

NASA Astrophysics Data System (ADS)

Ivanjek, Lana; Susac, Ana; Planinic, Maja; Andrasevic, Aneta; Milin-Sipus, Zeljka

2016-06-01

This study investigates university students' graph interpretation strategies and difficulties in mathematics, physics (kinematics), and contexts other than physics. Eight sets of parallel (isomorphic) mathematics, physics, and other context questions about graphs, which were developed by us, were administered to 385 first-year students at the Faculty of Science, University of Zagreb. Students were asked to provide explanations and/or mathematical procedures with their answers. Students' main strategies and difficulties identified through the analysis of those explanations and procedures are described. Student strategies of graph interpretation were found to be largely context dependent and domain specific. A small fraction of students have used the same strategy in all three domains (mathematics, physics, and other contexts) on most sets of parallel questions. Some students have shown indications of transfer of knowledge in the sense that they used techniques and strategies developed in physics for solving (or attempting to solve) other context problems. In physics, the preferred strategy was the use of formulas, which sometimes seemed to block the use of other, more productive strategies which students displayed in other domains. Students' answers indicated the presence of slope-height confusion and interval-point confusion in all three domains. Students generally better interpreted graph slope than the area under a graph, although the concept of slope still seemed to be quite vague for many. The interpretation of the concept of area under a graph needs more attention in both physics and mathematics teaching.

Natural Scherk-Schwarz theories of the weak scale

DOE PAGES

García, Isabel Garcia; Howe, Kiel; March-Russell, John

2015-12-01

Natural supersymmetric theories of the weak scale are under growing pressure given present LHC constraints, raising the question of whether untuned supersymmetric (SUSY) solutions to the hierarchy problem are possible. In this paper, we explore a class of 5-dimensional natural SUSY theories in which SUSY is broken by the Scherk-Schwarz mechanism. We pedagogically explain how Scherk-Schwarz elegantly solves the traditional problems of 4-dimensional SUSY theories (based on the MSSM and its many variants) that usually result in an unsettling level of fine-tuning. The minimal Scherk-Schwarz set up possesses novel phenomenology, which we briefly outline. In this study, we show thatmore » achieving the observed physical Higgs mass motivates extra structure that does not significantly affect the level of tuning (always better than ~10%) and we explore three qualitatively different extensions: the addition of extra matter that couples to the Higgs, an extra U(1)' gauge group under which the Higgs is charged and an NMSSM-like solution to the Higgs mass problem.« less

Examining Problem Solving in Physics-Intensive Ph.D. Research

ERIC Educational Resources Information Center

Leak, Anne E.; Rothwell, Susan L.; Olivera, Javier; Zwickl, Benjamin; Vosburg, Jarrett; Martin, Kelly Norris

2017-01-01

Problem-solving strategies learned by physics undergraduates should prepare them for real-world contexts as they transition from students to professionals. Yet, graduate students in physics-intensive research face problems that go beyond problem sets they experienced as undergraduates and are solved by different strategies than are typically…

Ways of thinking: from crows to children and back again.

PubMed

Clayton, Nicola S

2015-01-01

This article reviews some of the recent work on the remarkable cognitive capacities of food-caching corvids. The focus will be on their ability to think about other minds and other times, and tool-using tests of physical problem solving. Research on developmental cognition suggests that young children do not pass similar tests until they are at least four years of age in the case of the social cognition experiments, and eight years of age in the case of the tasks that tap into physical cognition. This developmental trajectory seems surprising. Intuitively, one might have thought that the social and planning tasks required more complex forms of cognitive process, namely Mental Time Travel and Theory of Mind. Perhaps the fact that children pass these tasks earlier than the physical problem-solving tasks is a reflection of cultural influences. Future research will hope to identify these cognitive milestones by starting to develop tasks that might go some way towards understanding the mechanisms underlying these abilities in both children and corvids, to explore similarities and differences in their ways of thinking.

A Summary of Some Discrete-Event System Control Problems

NASA Astrophysics Data System (ADS)

Rudie, Karen

A summary of the area of control of discrete-event systems is given. In this research area, automata and formal language theory is used as a tool to model physical problems that arise in technological and industrial systems. The key ingredients to discrete-event control problems are a process that can be modeled by an automaton, events in that process that cannot be disabled or prevented from occurring, and a controlling agent that manipulates the events that can be disabled to guarantee that the process under control either generates all the strings in some prescribed language or as many strings as possible in some prescribed language. When multiple controlling agents act on a process, decentralized control problems arise. In decentralized discrete-event systems, it is presumed that the agents effecting control cannot each see all event occurrences. Partial observation leads to some problems that cannot be solved in polynomial time and some others that are not even decidable.

An intelligent tutoring system for teaching fundamental physics concepts

NASA Astrophysics Data System (ADS)

Albacete, Patricia Lucia

1999-12-01

Students in traditional elementary mechanics classes can master problem solving of a quantitative nature but not those of a qualitative type. Moreover, students' naive conceptions of physics remain unchanged after completing their class. A few approaches have been implemented to improve this situation however none have met with great success. Since elementary mechanics is the foundation for all of physics and it is a required course for most science majors there is a clear need to improve the instruction of the subject. To address this problem I developed a intelligent tutoring system, called the Conceptual Helper, which coaches students during homework problem solving. The tutor uses a unique cognitive based approach to teaching physics, which presents innovations in three areas. (1) The teaching strategy, which focuses on teaching those links among the concepts of the domain that are essential for conceptual understanding yet are seldom learned by the students. (2) The manner in which the knowledge is taught, which is based on a combination of effective human tutoring techniques (e.g., hinting), effective pedagogical methods (e.g., a microscopic view of matter), and less cognitively demanding approaches (e.g., anthropomorphism). (3) The way in which misconceptions are handled which uses the underlying scientific correct line of reasoning to describe to the student the phenomenon that is the basis for the misconception. From a technological point of view the Conceptual Helper was implemented as a model-tracing tutor which intervenes when students make errors and after completion of each problem, at which time the tutor scaffolds the students on post-problem reflection. The remediation is guided by probabilistic assessment of mastery and the interventions are adapted to the errors. The thesis also presents the results of the evaluation of the system which revealed that the gain scores of the experimental group were statistically significantly higher than those of the control group, suggesting that the Conceptual Helper was indeed capable of effectively teaching the conceptual aspects of physics as well as helped students abandon common misconceptions. Furthermore, the evaluation showed that the students' performance on a standardized test was comparable to those of other more complex approaches.

Does job burnout mediate negative effects of job demands on mental and physical health in a group of teachers? Testing the energetic process of Job Demands-Resources model.

PubMed

Baka, Łukasz

2015-01-01

The aim of the study was to investigate the direct and indirect - mediated by job burnout - effects of job demands on mental and physical health problems. The Job Demands-Resources model was the theoretical framework of the study. Three job demands were taken into account - interpersonal conflicts at work, organizational constraints and workload. Indicators of mental and physical health problems included depression and physical symptoms, respectively. Three hundred and sixteen Polish teachers from 8 schools participated in the study. The hypotheses were tested with the use of tools measuring job demands (Interpersonal Conflicts at Work, Organizational Constraints, Quantitative Workload), job burnout (the Oldenburg Burnout Inventory), depression (the Beck Hopelessness Scale), and physical symptoms (the Physical Symptoms Inventory). The regression analysis with bootstrapping, using the PROCESS macros of Hayes was applied. The results support the hypotheses partially. The indirect effect and to some extent the direct effect of job demands turned out to be statistically important. The negative impact of 3 job demands on mental (hypothesis 1 - H1) and physical (hypothesis 2 - H2) health were mediated by the increasing job burnout. Only organizational constraints were directly associated with mental (and not physical) health. The results partially support the notion of the Job Demands-Resources model and provide further insight into processes leading to the low well-being of teachers in the workplace. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Perspective: Machine learning potentials for atomistic simulations

NASA Astrophysics Data System (ADS)

Behler, Jörg

2016-11-01

Nowadays, computer simulations have become a standard tool in essentially all fields of chemistry, condensed matter physics, and materials science. In order to keep up with state-of-the-art experiments and the ever growing complexity of the investigated problems, there is a constantly increasing need for simulations of more realistic, i.e., larger, model systems with improved accuracy. In many cases, the availability of sufficiently efficient interatomic potentials providing reliable energies and forces has become a serious bottleneck for performing these simulations. To address this problem, currently a paradigm change is taking place in the development of interatomic potentials. Since the early days of computer simulations simplified potentials have been derived using physical approximations whenever the direct application of electronic structure methods has been too demanding. Recent advances in machine learning (ML) now offer an alternative approach for the representation of potential-energy surfaces by fitting large data sets from electronic structure calculations. In this perspective, the central ideas underlying these ML potentials, solved problems and remaining challenges are reviewed along with a discussion of their current applicability and limitations.

University Students' Strategies for Constructing Hypothesis when Tackling Paper-and-Pencil Tasks in Physics

NASA Astrophysics Data System (ADS)

Guisasola, Jenaro; Ceberio, Mikel; Zubimendi, José Luis

2006-09-01

The study we present tries to explore how first year engineering students formulate hypotheses in order to construct their own problem solving structure when confronted with problems in physics. Under the constructivistic perspective of the teaching-learning process, the formulation of hypotheses plays a key role in contrasting the coherence of the students' ideas with the theoretical frame. The main research instrument used to identify students' reasoning is the written report by the student on how they have attempted four problem solving tasks in which they have been asked explicitly to formulate hypotheses. The protocols used in the assessment of the solutions consisted of a semi-quantitative study based on grids designed for the analysis of written answers. In this paper we have included two of the tasks used and the corresponding scheme for the categorisation of the answers. Details of the other two tasks are also outlined. According to our findings we would say that the majority of students judge a hypothesis to be plausible if it is congruent with their previous knowledge without rigorously checking it against the theoretical framework explained in class.

On the existence of solutions to a one-dimensional degenerate nonlinear wave equation

NASA Astrophysics Data System (ADS)

Hu, Yanbo

2018-07-01

This paper is concerned with the degenerate initial-boundary value problem to the one-dimensional nonlinear wave equation utt =((1 + u) aux) x which arises in a number of various physical contexts. The global existence of smooth solutions to the degenerate problem was established under relaxed conditions on the initial-boundary data by the characteristic decomposition method. Moreover, we show that the solution is uniformly C 1 , α continuous up to the degenerate boundary and the degenerate curve is C 1 , α continuous for α ∈ (0 , min ⁡ a/1+a, 1/1+a).

Examining problem solving in physics-intensive Ph.D. research

NASA Astrophysics Data System (ADS)

Leak, Anne E.; Rothwell, Susan L.; Olivera, Javier; Zwickl, Benjamin; Vosburg, Jarrett; Martin, Kelly Norris

2017-12-01

Problem-solving strategies learned by physics undergraduates should prepare them for real-world contexts as they transition from students to professionals. Yet, graduate students in physics-intensive research face problems that go beyond problem sets they experienced as undergraduates and are solved by different strategies than are typically learned in undergraduate coursework. This paper expands the notion of problem solving by characterizing the breadth of problems and problem-solving processes carried out by graduate students in physics-intensive research. We conducted semi-structured interviews with ten graduate students to determine the routine, difficult, and important problems they engage in and problem-solving strategies they found useful in their research. A qualitative typological analysis resulted in the creation of a three-dimensional framework: context, activity, and feature (that made the problem challenging). Problem contexts extended beyond theory and mathematics to include interactions with lab equipment, data, software, and people. Important and difficult contexts blended social and technical skills. Routine problem activities were typically well defined (e.g., troubleshooting), while difficult and important ones were more open ended and had multiple solution paths (e.g., evaluating options). In addition to broadening our understanding of problems faced by graduate students, our findings explore problem-solving strategies (e.g., breaking down problems, evaluating options, using test cases or approximations) and characteristics of successful problem solvers (e.g., initiative, persistence, and motivation). Our research provides evidence of the influence that problems students are exposed to have on the strategies they use and learn. Using this evidence, we have developed a preliminary framework for exploring problems from the solver's perspective. This framework will be examined and refined in future work. Understanding problems graduate students face and the strategies they use has implications for improving how we approach problem solving in undergraduate physics and physics education research.

Assessing Student Expertise in Introductory Physics with Isomorphic Problems. II. Effect of Some Potential Factors on Problem Solving and Transfer

ERIC Educational Resources Information Center

Chandralekha; Singh

2008-01-01

In this paper, we explore the use of isomorphic problem pairs (IPPs) to assess introductory physics students' ability to solve and successfully transfer problem-solving knowledge from one context to another in mechanics. We call the paired problems "isomorphic" because they require the same physics principle to solve them. We analyze written…

Understanding student use of mathematics in IPLS with the Math Epistemic Games Survey

NASA Astrophysics Data System (ADS)

Eichenlaub, Mark; Hemingway, Deborah; Redish, Edward F.

2017-01-01

We present the Math Epistemic Games Survey (MEGS), a new concept inventory on the use of mathematics in introductory physics for the life sciences. The survey asks questions that are often best-answered via techniques commonly-valued in physics instruction, including dimensional analysis, checking special or extreme cases, understanding scaling relationships, interpreting graphical representations, estimation, and mapping symbols onto physical meaning. MEGS questions are often rooted in quantitative biology. We present preliminary data on the validation and administration of the MEGS in a large, introductory physics for the life sciences course at the University of Maryland, as well as preliminary results on the clustering of questions and responses as a guide to student resource activation in problem solving. This material is based upon work supported by the US National Science Foundation under Award No. 15-04366.

Tendinopathy: Evidence-Informed Physical Therapy Clinical Reasoning.

PubMed

Vicenzino, Bill

2015-11-01

Patients presenting with pain at the tendon, which is associated with physical tasks and activities that specifically load that tendon, are at the center of this special issue. The current terminology for a symptomatic tendon presentation is tendinopathy, as this does not denote an underlying pathology, but rather signals that all is not well in the tendon. Tendinopathy is a prevalent and substantial problem, as it interferes with a person's capacity to lead a physically active and healthy life, which has a considerable flow-on effect on society in general. This issue deals with the contemporary physical therapy management of tendinopathy by providing a mix of evidence review and clinical expert opinion on commonly presenting tendinopathies of the lower and upper limbs. J Orthop Sports Phys Ther 2015;45(11):816-818. doi:10.2519/jospt.2015.0110.

What Works with Worked Examples: Extending Self-Explanation and Analogical Comparison to Synthesis Problems

ERIC Educational Resources Information Center

Badeau, Ryan; White, Daniel R.; Ibrahim, Bashirah; Ding, Lin; Heckler, Andrew F.

2017-01-01

The ability to solve physics problems that require multiple concepts from across the physics curriculum--"synthesis" problems--is often a goal of physics instruction. Three experiments were designed to evaluate the effectiveness of two instructional methods employing worked examples on student performance with synthesis problems; these…

TerraFERMA: The Transparent Finite Element Rapid Model Assembler for multi-physics problems in the solid Earth sciences

NASA Astrophysics Data System (ADS)

Spiegelman, M. W.; Wilson, C. R.; Van Keken, P. E.

2013-12-01

We announce the release of a new software infrastructure, TerraFERMA, the Transparent Finite Element Rapid Model Assembler for the exploration and solution of coupled multi-physics problems. The design of TerraFERMA is driven by two overarching computational needs in Earth sciences. The first is the need for increased flexibility in both problem description and solution strategies for coupled problems where small changes in model assumptions can often lead to dramatic changes in physical behavior. The second is the need for software and models that are more transparent so that results can be verified, reproduced and modified in a manner such that the best ideas in computation and earth science can be more easily shared and reused. TerraFERMA leverages three advanced open-source libraries for scientific computation that provide high level problem description (FEniCS), composable solvers for coupled multi-physics problems (PETSc) and a science neutral options handling system (SPuD) that allows the hierarchical management of all model options. TerraFERMA integrates these libraries into an easier to use interface that organizes the scientific and computational choices required in a model into a single options file, from which a custom compiled application is generated and run. Because all models share the same infrastructure, models become more reusable and reproducible. TerraFERMA inherits much of its functionality from the underlying libraries. It currently solves partial differential equations (PDE) using finite element methods on simplicial meshes of triangles (2D) and tetrahedra (3D). The software is particularly well suited for non-linear problems with complex coupling between components. We demonstrate the design and utility of TerraFERMA through examples of thermal convection and magma dynamics. TerraFERMA has been tested successfully against over 45 benchmark problems from 7 publications in incompressible and compressible convection, magmatic solitary waves and Stokes flow with free surfaces. We have been using it extensively for research in basic magma dynamics, fluid flow in subduction zones and reactive cracking in poro-elastic materials. TerraFERMA is open-source and available as a git repository at bitbucket.org/tferma/tferma and through CIG. Instability of a 1-D magmatic solitary wave to spherical 3D waves calculated using TerraFERMA

Attitude and practice of physical activity and social problem-solving ability among university students.

PubMed

Sone, Toshimasa; Kawachi, Yousuke; Abe, Chihiro; Otomo, Yuki; Sung, Yul-Wan; Ogawa, Seiji

2017-04-04

Effective social problem-solving abilities can contribute to decreased risk of poor mental health. In addition, physical activity has a favorable effect on mental health. These previous studies suggest that physical activity and social problem-solving ability can interact by helping to sustain mental health. The present study aimed to determine the association between attitude and practice of physical activity and social problem-solving ability among university students. Information on physical activity and social problem-solving was collected using a self-administered questionnaire. We analyzed data from 185 students who participated in the questionnaire surveys and psychological tests. Social problem-solving as measured by the Social Problem-Solving Inventory-Revised (SPSI-R) (median score 10.85) was the dependent variable. Multiple logistic regression analysis was employed to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for higher SPSI-R according to physical activity categories. The multiple logistic regression analysis indicated that the ORs (95% CI) in reference to participants who said they never considered exercising were 2.08 (0.69-6.93), 1.62 (0.55-5.26), 2.78 (0.86-9.77), and 6.23 (1.81-23.97) for participants who did not exercise but intended to start, tried to exercise but did not, exercised but not regularly, and exercised regularly, respectively. This finding suggested that positive linear association between physical activity and social problem-solving ability (p value for linear trend < 0.01). The present findings suggest that regular physical activity or intention to start physical activity may be an effective strategy to improve social problem-solving ability.

Lung function requirements in flying duty the problem of bronchial hyperresponsiveness in military aircrew.

PubMed

Hartmann, C M; Steinhoff-Lankes, D; Maya-Pelzer, P

1999-09-09

Uncompromised lung function is essential for fitness to fly. Under hypobaric conditions there is an increased risk of hypoxemia. G-forces, positive pressure breathing and anti-G maneuvers cause physical stress to the lung tissue and altered pulmonary blood flow. Breathing with pure oxygen, dry cabin air and ozone can cause airway irritation. Chemically and physically by irritating agents may be present. Emergencies such as smoke in the cockpit or inhalation of tear gas can rapidly compromise the pulmonary system in susceptible persons. Sudden incapacitation may occur. Trapped gases may cause overinflation and lung rupture in rapid decompression. Applicants for military duty have to pass basic lung function tests routinely. Preselection of aircrew candidates tends to be even stricter. Asthma and obstructive lung disease are disqualifying. Trained aircrew with late onset of pulmonary problems can be waived under certain restrictions in many cases. Some national regulations exclude even applicants with allergies. Due to aeromedical experience we should always be aware of the latent unspecific bronchial hyperresponsiveness (BHR). BHR is one of the characteristics of asthma bronchiale. If BHR exists there is an increased risk of later development of asthma bronchiale, especially together with perennial allergies such as against house dust mite. Under certain conditions BHR can become symptomatic and aeromedically relevant. In some cases we saw an exacerbation under medication, mostly under beta-receptor-blockers. In one case even under betablocker-containing eye drops. In the Gulf War 1991 a number of allied military personnel had to be withdrawn because of bronchospastic symptoms. This can be explained among others by medication with physostigmine. Physostigmine is a systemically active cholinergic drug which is prophylactically used under threat of chemically warfare agents. In individuals with latent BHR physostigmine will lower the threshold for bronchial reactions considerably and even cause manifest bronchospasm. We recommend an unspecific bronchial challenge test in the selection of personnel for duties where uncompromised lung function under all environmental conditions is essential.

INTERNATIONAL COMPARISON EXERCISE ON NEUTRON SPECTRA UNFOLDING IN BONNER SPHERES SPECTROMETRY: PROBLEM DESCRIPTION AND PRELIMINARY ANALYSIS.

PubMed

Gómez-Ros, J M; Bedogni, R; Domingo, C; Eakins, J S; Roberts, N; Tanner, R J

2018-01-29

This article describes the purpose, the proposed problems and the reference solutions of an international comparison on neutron spectra unfolding in Bonner spheres spectrometry, organised within the activities of EURADOS working group 6: computational dosimetry. The exercise considered four realistic situations: a medical accelerator, a workplace field, an irradiation room and a skyshine scenario. Although a detailed analysis of the submitted solutions is under preparation, the preliminary discussion of some physical aspects of the problem, e.g. the changes in the unfolding results due to the perturbation of the neutron field by the Bonner spheres, is presented. © The Author(s) 2018. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A Course on the Physics of Urban and Environmental Problems

ERIC Educational Resources Information Center

Marston, Edwin H.

1970-01-01

Presents a physics course for social scientists. Physics problems are presented within the context of several urban and environmental case studies. The problems considered include transportation, air pollution, thermal pollution of water, and scarcity of resources. (LS)

Problem solving in the borderland between mathematics and physics

NASA Astrophysics Data System (ADS)

Jensen, Jens Højgaard; Niss, Martin; Jankvist, Uffe Thomas

2017-01-01

The article addresses the problématique of where mathematization is taught in the educational system, and who teaches it. Mathematization is usually not a part of mathematics programs at the upper secondary level, but we argue that physics teaching has something to offer in this respect, if it focuses on solving so-called unformalized problems, where a major challenge is to formalize the problems in mathematics and physics terms. We analyse four concrete examples of unformalized problems for which the formalization involves different order of mathematization and applying physics to the problem, but all require mathematization. The analysis leads to the formulation of a model by which we attempt to capture the important steps of the process of solving unformalized problems by means of mathematization and physicalization.

Plasma physics of extreme astrophysical environments.

PubMed

Uzdensky, Dmitri A; Rightley, Shane

2014-03-01

Among the incredibly diverse variety of astrophysical objects, there are some that are characterized by very extreme physical conditions not encountered anywhere else in the Universe. Of special interest are ultra-magnetized systems that possess magnetic fields exceeding the critical quantum field of about 44 TG. There are basically only two classes of such objects: magnetars, whose magnetic activity is manifested, e.g., via their very short but intense gamma-ray flares, and central engines of supernovae (SNe) and gamma-ray bursts (GRBs)--the most powerful explosions in the modern Universe. Figuring out how these complex systems work necessarily requires understanding various plasma processes, both small-scale kinetic and large-scale magnetohydrodynamic (MHD), that govern their behavior. However, the presence of an ultra-strong magnetic field modifies the underlying basic physics to such a great extent that relying on conventional, classical plasma physics is often not justified. Instead, plasma-physical problems relevant to these extreme astrophysical environments call for constructing relativistic quantum plasma (RQP) physics based on quantum electrodynamics (QED). In this review, after briefly describing the astrophysical systems of interest and identifying some of the key plasma-physical problems important to them, we survey the recent progress in the development of such a theory. We first discuss the ways in which the presence of a super-critical field modifies the properties of vacuum and matter and then outline the basic theoretical framework for describing both non-relativistic and RQPs. We then turn to some specific astrophysical applications of relativistic QED plasma physics relevant to magnetar magnetospheres and to central engines of core-collapse SNe and long GRBs. Specifically, we discuss the propagation of light through a magnetar magnetosphere; large-scale MHD processes driving magnetar activity and responsible for jet launching and propagation in GRBs; energy-transport processes governing the thermodynamics of extreme plasma environments; micro-scale kinetic plasma processes important in the interaction of intense electric currents flowing through a magnetar magnetosphere with the neutron star surface; and magnetic reconnection of ultra-strong magnetic fields. Finally, we point out that future progress in applying RQP physics to real astrophysical problems will require the development of suitable numerical modeling capabilities.

Computational Studies of Strongly Correlated Quantum Matter

NASA Astrophysics Data System (ADS)

Shi, Hao

The study of strongly correlated quantum many-body systems is an outstanding challenge. Highly accurate results are needed for the understanding of practical and fundamental problems in condensed-matter physics, high energy physics, material science, quantum chemistry and so on. Our familiar mean-field or perturbative methods tend to be ineffective. Numerical simulations provide a promising approach for studying such systems. The fundamental difficulty of numerical simulation is that the dimension of the Hilbert space needed to describe interacting systems increases exponentially with the system size. Quantum Monte Carlo (QMC) methods are one of the best approaches to tackle the problem of enormous Hilbert space. They have been highly successful for boson systems and unfrustrated spin models. For systems with fermions, the exchange symmetry in general causes the infamous sign problem, making the statistical noise in the computed results grow exponentially with the system size. This hinders our understanding of interesting physics such as high-temperature superconductivity, metal-insulator phase transition. In this thesis, we present a variety of new developments in the auxiliary-field quantum Monte Carlo (AFQMC) methods, including the incorporation of symmetry in both the trial wave function and the projector, developing the constraint release method, using the force-bias to drastically improve the efficiency in Metropolis framework, identifying and solving the infinite variance problem, and sampling Hartree-Fock-Bogoliubov wave function. With these developments, some of the most challenging many-electron problems are now under control. We obtain an exact numerical solution of two-dimensional strongly interacting Fermi atomic gas, determine the ground state properties of the 2D Fermi gas with Rashba spin-orbit coupling, provide benchmark results for the ground state of the two-dimensional Hubbard model, and establish that the Hubbard model has a stripe order in the underdoped region.

Dental management of patient with Williams Syndrome - A case report.

PubMed

Wong, Daniel; Ramachandra, Srinivas Sulugodu; Singh, Ashish Kumar

2015-01-01

Williams syndrome is a multisystemic rare genetic disorder caused by deletion of 26-28 genes in the long arm of chromosome 7. It is characterized by developmental and physical abnormalities including congenital cardiovascular abnormalities, mental retardation, neurological features, growth deficiency, genitourinary manifestations, gastrointestinal problems, musculoskeletal problems, unique behavioral characteristics, and dental problems. Dental abnormalities include malocclusion, hypodontia, malformed teeth, taurodontism, pulp stones, increased space between teeth, enamel hypoplasia, and high prevalence of dental caries. Authors report a 17-year-old female patient with underlying Williams syndrome. Oral features and problems seen in the patient are listed. Malocclusion and screwdriver shaped teeth were noticed. Generalized widening of the periodontal ligament space with vital teeth was seen. This finding has not been reported in cases of Williams syndrome earlier. Precautions taken during dental treatment in patients with Williams syndrome are also discussed.

Contact in an expanding universe: an instructive exercise in dynamic geometry

NASA Astrophysics Data System (ADS)

Zimmerman, Seth

2010-11-01

The particular problem solved in this paper is that of calculating the time required to overtake a distant object receding under cosmic expansion, and the speed at which that object is passed. This is a rarely investigated problem leading to some interesting apparent paradoxes. We employ the problem to promote a deeper understanding of the dynamic geometry behind the expansion of space in three eras, especially for physics undergraduates. We do not utilize the standard cosmological formulae, but deliberately take a simpler approach, comprehensible to any student comfortable with differentials. This should offer an intuitive preparation for later courses in general relativity. The paper can be read straight through, or offered to a class in segments as problems to investigate. The overall intention is to leave students with a more tangible grasp of expanding space.

Minimum relative entropy distributions with a large mean are Gaussian

NASA Astrophysics Data System (ADS)

Smerlak, Matteo

2016-12-01

Entropy optimization principles are versatile tools with wide-ranging applications from statistical physics to engineering to ecology. Here we consider the following constrained problem: Given a prior probability distribution q , find the posterior distribution p minimizing the relative entropy (also known as the Kullback-Leibler divergence) with respect to q under the constraint that mean (p ) is fixed and large. We show that solutions to this problem are approximately Gaussian. We discuss two applications of this result. In the context of dissipative dynamics, the equilibrium distribution of a Brownian particle confined in a strong external field is independent of the shape of the confining potential. We also derive an H -type theorem for evolutionary dynamics: The entropy of the (standardized) distribution of fitness of a population evolving under natural selection is eventually increasing in time.

Treating malnutrition in the community.

PubMed

Dera, Merceline; Woodham, Diane

2016-11-02

Malnutrition is a clinical and public health problem. It has adverse effects on the physical and psycho-social wellbeing of individuals by predisposing to disease, negatively affecting its outcome and reducing the likelihood of independence. An estimated 3 million people in the UK are affected by malnutrition, most of whom live in the community ( BAPEN, 2011 ). Despite the scale of this problem, it remains under-detected, under-treated, underresourced and often overlooked by those involved in the care of at risks individuals such as the elderly. In most cases malnutrition is a treatable condition that can be managed by optimising food intake and using oral nutritional supplements (ONS) where necessary. The main focus of this article is on the dangers of malnutrition for older people in the community and the use of ONS in the treatment and management of malnutrition.

On electron bunching and stratification of glow discharges

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

Golubovskii, Yuri B.; Kolobov, Vladimir I.; Nekuchaev, Vladimir O.

2013-10-15

Plasma stratification and excitation of ionization waves is one of the fundamental problems in gas discharge physics. Significant progress in this field is associated with the name of Lev Tsendin. He advocated the need for the kinetic approach to this problem contrary to the traditional hydrodynamic approach, introduced the idea of electron bunching in spatially periodic electric fields, and developed a theory of kinetic resonances for analysis of moving striations in rare gases. The present paper shows how Tsendin's ideas have been further developed and applied for understanding the nature of the well-known S-, P-, and R-striations observed in glowmore » discharges of inert gases at low pressures and currents. We review numerical solutions of a Fokker-Planck kinetic equation in spatially periodic electric fields under the effects of elastic and inelastic collisions of electrons with atoms. We illustrate the formation of kinetic resonances at specific field periods for different shapes of injected Electron Distribution Functions (EDF). Computer simulations illustrate how self-organization of the EDFs occurs under nonlocal conditions and how Gaussian-like peaks moving along resonance trajectories are formed in a certain range of discharge conditions. The calculated EDFs agree well with the experimentally measured EDFs for the S, P, and R striations in noble gases. We discuss how kinetic resonances affect dispersion characteristics of moving striations and mention some non-linear effects associated with glow discharge stratification. We propose further studies of stratification phenomena combining physical kinetics and non-linear physics.« less

Relationships between undergraduates' argumentation skills, conceptual quality of problem solutions, and problem solving strategies in introductory physics

NASA Astrophysics Data System (ADS)

Rebello, Carina M.

This study explored the effects of alternative forms of argumentation on undergraduates' physics solutions in introductory calculus-based physics. A two-phase concurrent mixed methods design was employed to investigate relationships between undergraduates' written argumentation abilities, conceptual quality of problem solutions, as well as approaches and strategies for solving argumentative physics problems across multiple physics topics. Participants were assigned via stratified sampling to one of three conditions (control, guided construct, or guided evaluate) based on gender and pre-test scores on a conceptual instrument. The guided construct and guided evaluate groups received tasks and prompts drawn from literature to facilitate argument construction or evaluation. Using a multiple case study design, with each condition serving as a case, interviews were conducted consisting of a think-aloud problem solving session paired with a semi-structured interview. The analysis of problem solving strategies was guided by the theoretical framework on epistemic games adapted by Tuminaro and Redish (2007). This study provides empirical evidence that integration of written argumentation into physics problems can potentially improve the conceptual quality of solutions, expand their repertoire of problem solving strategies and show promise for addressing the gender gap in physics. The study suggests further avenues for research in this area and implications for designing and implementing argumentation tasks in introductory college physics.

Diversity of Approaches to Problems by Students Enrolled in a Non-Calculus College Physics Course.

ERIC Educational Resources Information Center

Cohen, Anna Foner

This study was undertaken to determine whether hierarchically structured problem situations could be developed and used to identify where individual solutions to problems in elementary physics are interrupted and whether examination of student approaches to problem situations would be useful to physics teaching. A random sample of 26 students…

Research Projects in Physics: A Mechanism for Teaching Ill-Structured Problem Solving

ERIC Educational Resources Information Center

Milbourne, Jeff; Bennett, Jonathan

2017-01-01

Physics education research has a tradition of studying problem solving, exploring themes such as physical intuition and differences between expert and novice problem solvers. However, most of this work has focused on traditional, or well-structured, problems, similar to what might appear in a textbook. Less work has been done with open-ended, or…

Problems Encountered by Religious Vocational Secondary School and Other Secondary School Students in Physical Education and Sports Activities

ERIC Educational Resources Information Center

Bar, Mustafa; Yaman, Menzure Sibel; Hergüner, Gülten

2016-01-01

The study aimed to determine problems encountered by Religious Vocational Secondary School and other Secondary School students in physical education and sports activities and to compare these problems according to school type and gender. A questionnaire named "Problems encountered in attending to physical education and sports activities"…

Integration of QFD, AHP, and LPP methods in supplier development problems under uncertainty

NASA Astrophysics Data System (ADS)

Shad, Zahra; Roghanian, Emad; Mojibian, Fatemeh

2014-04-01

Quality function deployment (QFD) is a customer-driven approach, widely used to develop or process new product to maximize customer satisfaction. Last researches used linear physical programming (LPP) procedure to optimize QFD; however, QFD issue involved uncertainties, or fuzziness, which requires taking them into account for more realistic study. In this paper, a set of fuzzy data is used to address linguistic values parameterized by triangular fuzzy numbers. Proposed integrated approach including analytic hierarchy process (AHP), QFD, and LPP to maximize overall customer satisfaction under uncertain conditions and apply them in the supplier development problem. The fuzzy AHP approach is adopted as a powerful method to obtain the relationship between the customer requirements and engineering characteristics (ECs) to construct house of quality in QFD method. LPP is used to obtain the optimal achievement level of the ECs and subsequently the customer satisfaction level under different degrees of uncertainty. The effectiveness of proposed method will be illustrated by an example.

A mathematical problem and a Spacecraft Control Laboratory Experiment (SCOLE) used to evaluate control laws for flexible spacecraft. NASA/IEEE design challenge

NASA Technical Reports Server (NTRS)

Taylor, Lawrence W., Jr.; Balakrishnan, A. V.

1988-01-01

The problen of controlling large, flexible space systems has been evaluated using computer simulation. In several cases, ground experiments have also been used to validate system performance under more realistic conditions. There remains a need, however, to test additional control laws for flexible spacecraft and to directly compare competing design techniques. A program is discussed which has been initiated to make direct comparisons of control laws for, first, a mathematical problem, then and experimental test article being assembled under the cognizance of the Spacecraft Control Branch at the NASA Langley Research Center with the advice and counsel of the IEEE Subcommittee on Large Space Structures. The physical apparatus will consist of a softly supported dynamic model of an antenna attached to the Shuttle by a flexible beam. The control objective will include the task of directing the line-of-sight of the Shuttle antenna configuration toward a fixed target, under conditions of noisy data, control authority and random disturbances.

SSC San Diego Biennial Review 2003. Command and Control

DTIC Science & Technology

2003-01-01

systems. IMAT systems use scientific visualizations, three- dimensional graphics, and animations to illustrate com- plex physical interactions in mission...Again, interactive animations are used to explain underlying concepts. For exam- ple, for principles of beamforming using a phased array, a three...solve complex problems. Experts type natural language text, use mouse clicks to provide hints for explanation generation, and use mouse clicks to

Analytical study and numerical solution of the inverse source problem arising in thermoacoustic tomography

NASA Astrophysics Data System (ADS)

Holman, Benjamin R.

In recent years, revolutionary "hybrid" or "multi-physics" methods of medical imaging have emerged. By combining two or three different types of waves these methods overcome limitations of classical tomography techniques and deliver otherwise unavailable, potentially life-saving diagnostic information. Thermoacoustic (and photoacoustic) tomography is the most developed multi-physics imaging modality. Thermo- and photo- acoustic tomography require reconstructing initial acoustic pressure in a body from time series of pressure measured on a surface surrounding the body. For the classical case of free space wave propagation, various reconstruction techniques are well known. However, some novel measurement schemes place the object of interest between reflecting walls that form a de facto resonant cavity. In this case, known methods cannot be used. In chapter 2 we present a fast iterative reconstruction algorithm for measurements made at the walls of a rectangular reverberant cavity with a constant speed of sound. We prove the convergence of the iterations under a certain sufficient condition, and demonstrate the effectiveness and efficiency of the algorithm in numerical simulations. In chapter 3 we consider the more general problem of an arbitrarily shaped resonant cavity with a non constant speed of sound and present the gradual time reversal method for computing solutions to the inverse source problem. It consists in solving back in time on the interval [0, T] the initial/boundary value problem for the wave equation, with the Dirichlet boundary data multiplied by a smooth cutoff function. If T is sufficiently large one obtains a good approximation to the initial pressure; in the limit of large T such an approximation converges (under certain conditions) to the exact solution.

Do mental health problems in childhood predict chronic physical conditions among males in early adulthood? Evidence from a community-based prospective study.

PubMed

Goodwin, R D; Sourander, A; Duarte, C S; Niemelä, S; Multimäki, P; Nikolakaros, G; Helenius, H; Piha, J; Kumpulainen, K; Moilanen, I; Tamminen, T; Almqvist, F

2009-02-01

Previous studies have documented associations between mental and physical health problems in cross-sectional studies, yet little is known about these relationships over time or the specificity of these associations. The aim of the current study was to examine the relationship between mental health problems in childhood at age 8 years and physical disorders in adulthood at ages 18-23 years. Multiple logistic regression analyses were used to examine the relationship between childhood mental health problems, reported by child, parent and teacher, and physical disorders diagnosed by a physician in early adulthood. Significant linkages emerged between childhood mental health problems and obesity, atopic eczema, epilepsy and asthma in early adulthood. Specifically, conduct problems in childhood were associated with a significantly increased likelihood of obesity and atopic eczema; emotional problems were associated with an increased likelihood of epilepsy and asthma; and depression symptoms at age 8 were associated with an increased risk of asthma in early adulthood. Our findings provide the first evidence of an association between mental health problems during childhood and increased risk of specific physical health problems, mainly asthma and obesity, during early adulthood, in a representative sample of males over time. These data suggest that behavioral and emotional problems in childhood may signal vulnerability to chronic physical health problems during early adulthood.

A Meta-Analysis of Disparities in Childhood Sexual Abuse, Parental Physical Abuse, and Peer Victimization Among Sexual Minority and Sexual Nonminority Individuals

PubMed Central

Marshal, Michael P.; Guadamuz, Thomas E.; Wei, Chongyi; Wong, Carolyn F.; Saewyc, Elizabeth; Stall, Ron

2011-01-01

Objectives. We compared the likelihood of childhood sexual abuse (under age 18), parental physical abuse, and peer victimization based on sexual orientation. Methods. We conducted a meta-analysis of adolescent school-based studies that compared the likelihood of childhood abuse among sexual minorities vs sexual nonminorities. Results. Sexual minority individuals were on average 3.8, 1.2, 1.7, and 2.4 times more likely to experience sexual abuse, parental physical abuse, or assault at school or to miss school through fear, respectively. Moderation analysis showed that disparities between sexual minority and sexual nonminority individuals were larger for (1) males than females for sexual abuse, (2) females than males for assault at school, and (3) bisexual than gay and lesbian for both parental physical abuse and missing school through fear. Disparities did not change between the 1990s and the 2000s. Conclusions. The higher rates of abuse experienced by sexual minority youths may be one of the driving mechanisms underlying higher rates of mental health problems, substance use, risky sexual behavior, and HIV reported by sexual minority adults. PMID:21680921

Commentary: physical approaches for the treatment of epilepsy: electrical and magnetic stimulation and cooling.

PubMed

Löscher, Wolfgang; Cole, Andrew J; McLean, Michael J

2009-04-01

Physical approaches for the treatment of epilepsy currently under study or development include electrical or magnetic brain stimulators and cooling devices, each of which may be implanted or applied externally. Some devices may stimulate peripheral structures, whereas others may be implanted directly into the brain. Stimulation may be delivered chronically, intermittently, or in response to either manual activation or computer-based detection of events of interest. Physical approaches may therefore ultimately be appropriate for seizure prophylaxis by causing a modification of the underlying substrate, presumably with a reduction in the intrinsic excitability of cerebral structures, or for seizure termination, by interfering with the spontaneous discharge of pathological neuronal networks. Clinical trials of device-based therapies are difficult due to ethical issues surrounding device implantation, problems with blinding, potential carryover effects that may occur in crossover designs if substrate modification occurs, and subject heterogeneity. Unresolved issues in the development of physical treatments include optimization of stimulation parameters, identification of the optimal volume of brain to be stimulated, development of adequate power supplies to stimulate the necessary areas, and a determination that stimulation itself does not promote epileptogenesis or adverse long-term effects on normal brain function.

A Measure Approximation for Distributionally Robust PDE-Constrained Optimization Problems

DOE PAGES

Kouri, Drew Philip

2017-12-19

In numerous applications, scientists and engineers acquire varied forms of data that partially characterize the inputs to an underlying physical system. This data is then used to inform decisions such as controls and designs. Consequently, it is critical that the resulting control or design is robust to the inherent uncertainties associated with the unknown probabilistic characterization of the model inputs. Here in this work, we consider optimal control and design problems constrained by partial differential equations with uncertain inputs. We do not assume a known probabilistic model for the inputs, but rather we formulate the problem as a distributionally robustmore » optimization problem where the outer minimization problem determines the control or design, while the inner maximization problem determines the worst-case probability measure that matches desired characteristics of the data. We analyze the inner maximization problem in the space of measures and introduce a novel measure approximation technique, based on the approximation of continuous functions, to discretize the unknown probability measure. Finally, we prove consistency of our approximated min-max problem and conclude with numerical results.« less

Focus group discussion in mathematical physics learning

NASA Astrophysics Data System (ADS)

Ellianawati; Rudiana, D.; Sabandar, J.; Subali, B.

2018-03-01

The Focus Group Discussion (FGD) activity in Mathematical Physics learning has helped students perform the stages of problem solving reflectively. The FGD implementation was conducted to explore the problems and find the right strategy to improve the students' ability to solve the problem accurately which is one of reflective thinking component that has been difficult to improve. The research method used is descriptive qualitative by using single subject response in Physics student. During the FGD process, one student was observed of her reflective thinking development in solving the physics problem. The strategy chosen in the discussion activity was the Cognitive Apprenticeship-Instruction (CA-I) syntax. Based on the results of this study, it is obtained the information that after going through a series of stages of discussion, the students' reflective thinking skills is increased significantly. The scaffolding stage in the CA-I model plays an important role in the process of solving physics problems accurately. Students are able to recognize and formulate problems by describing problem sketches, identifying the variables involved, applying mathematical equations that accord to physics concepts, executing accurately, and applying evaluation by explaining the solution to various contexts.

The profile of students’ problem-solving skill in physics across interest program in the secondary school

NASA Astrophysics Data System (ADS)

Jua, S. K.; Sarwanto; Sukarmin

2018-05-01

Problem-solving skills are important skills in physics. However, according to some researchers, the problem-solving skill of Indonesian students’ problem in physics learning is categorized still low. The purpose of this study was to identify the profile of problem-solving skills of students who follow the across the interests program of physics. The subjects of the study were high school students of Social Sciences, grade X. The type of this research was descriptive research. The data which used to analyze the problem-solving skills were obtained through student questionnaires and the test results with impulse materials and collision. From the descriptive analysis results, the percentage of students’ problem-solving skill based on the test was 52.93% and indicators respectively. These results indicated that students’ problem-solving skill is categorized low.

Early Adversity, Psychopathology, and Latent Class Profiles of Global Physical Health From Preschool Through Early Adolescence.

PubMed

Whalen, Diana J; Belden, Andy C; Tillman, Rebecca; Barch, Deanna M; Luby, Joan L

The purpose of the present report was to describe the longitudinal trajectories of physical health beginning during preschool and continuing into early adolescence; explore whether these trajectories were predicted by psychosocial adversity, family income-to-needs ratio, and psychiatric disorders occurring during the preschool period; and determine whether psychiatric disorders mediated these relations. Participants included 296 children participating in a longitudinal study of early-onset psychopathology spanning 10 years. Semistructured clinical interviews were conducted with caregivers to determine children's psychiatric diagnoses between ages 3 and 6 years. Caregivers also completed annual assessments of their child's physical health problems (ages 3-13) and reported on the family's income and indicators of psychosocial adversity. Growth mixture modeling revealed 2 trajectories of physical health problems: a stable, low group (n = 199) and a high, increasing group (n = 57) indicating linear increases in physical health problems from ages 3 to 13. Preschool psychiatric diagnoses (Estimate [Est] = 0.05, p < .001), family income-to-needs ratio (Est = -0.01, p = .012), and psychosocial adversity (Est = 0.02, p = .015) predicted membership in the high, increasing trajectory of physical health problems. Early-onset psychopathology mediated relations between psychosocial adversity and physical health problems (αβ = 0.31, p = .050) and between income-to-needs ratio and physical health problems (αβ = -0.29, p < .021). These findings indicate the importance of early indicators of risk: low income-to-needs ratios, high psychosocial adversity, and psychiatric disorders occurring during the preschool period for contributing to increasing physical health problems from preschool through early adolescence. Early-onset psychiatric disorders also mediated relations between psychosocial adversity, income-to-needs ratio, and physical health problems.

Early adversity, psychopathology, and latent class profiles of global physical health from preschool through early adolescence

PubMed Central

Whalen, Diana J.; Belden, Andy C.; Tillman, Rebecca; Barch, Deanna M.; Luby, Joan L.

2016-01-01

Objective The purpose of the present report was to describe the longitudinal trajectories of physical health beginning during preschool and continuing into early adolescence, explore whether these trajectories were predicted by psychosocial adversity, family income-to-needs ratio, and psychiatric disorders occurring during the preschool period, and determine whether psychiatric disorders mediated these relations. Methods Participants included 296 children participating in a longitudinal study of early-onset psychopathology spanning ten years. Semi-structured clinical interviews were conducted with caregivers to determine children’s psychiatric diagnoses between ages 3–6. Caregivers also completed annual assessments of their child’s physical health problems (ages 3–13), as well as reported on the family’s income and indicators of psychosocial adversity. Results Growth mixture modeling revealed two trajectories of physical health problems: a stable, low group (n = 199) and a high, increasing group (n = 57) indicating linear increases in physical health problems from ages 3–13. Preschool psychiatric diagnoses (Est= 0.05, p<.001), family income-to-needs ratio (Est= −0.01, p=.012), and psychosocial adversity (Est=0.02, p=.015) predicted membership in the high, increasing trajectory of physical health problems. Early-onset psychopathology mediated relations between psychosocial adversity and physical health problems (αβ= 0.31, p=.050) and between income-to-needs ratio and physical health problems (αβ= −0.29, p<.021). Conclusions These findings indicate the importance of early indicators of risk: low income-to-needs ratios, high psychosocial adversity, and psychiatric disorders occurring during the preschool period for contributing to increasing physical health problems from preschool through early adolescence. Early-onset psychiatric disorders also mediated relations between psychosocial adversity, income-to-needs ratio, and physical health problems. PMID:27749744

Screening for Depressive Disorder in Elderly Patients with Chronic Physical Diseases Using the Patient Health Questionnaire-9

PubMed Central

Park, Seon-Cheol; Lee, Dong-Woo; Hahn, Sang-Woo; Park, Sang-Ho; Kim, Yeo Ju; Choi, Jae Sung; Lee, Ho-Sung; Lee, Soyoung Irene; Na, Kyoung-Sae; Jung, Sung Won; Shim, Se-Hoon; Kim, Ki Won; Paik, Jong-Woo; Kwon, Young-Joon

2017-01-01

Objective We aimed to identify depressive symptom profiles that indicated the presence of depressive disorder and present optimal cut-off sub-scores for depressive symptom profiles for detecting depressive disorder in elderly subjects with chronic physical diseases including diabetes, chronic obstructive pulmonary disease/asthma, and coronary artery disease, using the Patient Health Questionnaire-9 (PHQ-9). Methods Two hundred and thirty-one elderly patients with chronic physical diseases were recruited consecutively from a university-affiliated general hospital in South Korea. Results Greater severities of all 9 depressive symptoms in the PHQ-9 were presented in those with depressive disorder rather than those without depressive disorder. A binary logistic regression modeling presented that little interest [adjusted odds ratio (aOR)=4.648, p<0.001], reduced/increased sleep (aOR=3.269, p<0.001), psychomotor retardation/agitation (aOR=2.243, p=0.004), and concentration problem (aOR=16.116, p<0.001) were independently associated with increased likelihood of having depressive disorder. Receiver operating characteristics (ROC) curve analysis presented that the optimal cut-off value of score on the items for little interest, reduced/increased sleep, psychomotor retardation/agitation and concentration problem (PHQ-9) for detecting depressive disorder was 4 with 61.9% of sensitivity and 91.5% of specificity [area under curve (AUC)=0.937, p<0.001]. Conclusion Our findings suggested that the diagnostic weighting of little interest, reduced/increased sleep, psychomotor retardation/agitation, and concentration problem is needed to detect depressive disorder among the elderly patients with chronic physical diseases. PMID:28539949

Screening for Depressive Disorder in Elderly Patients with Chronic Physical Diseases Using the Patient Health Questionnaire-9.

PubMed

Park, Seon-Cheol; Lee, Hwa-Young; Lee, Dong-Woo; Hahn, Sang-Woo; Park, Sang-Ho; Kim, Yeo Ju; Choi, Jae Sung; Lee, Ho-Sung; Lee, Soyoung Irene; Na, Kyoung-Sae; Jung, Sung Won; Shim, Se-Hoon; Kim, Ki Won; Paik, Jong-Woo; Kwon, Young-Joon

2017-05-01

We aimed to identify depressive symptom profiles that indicated the presence of depressive disorder and present optimal cut-off sub-scores for depressive symptom profiles for detecting depressive disorder in elderly subjects with chronic physical diseases including diabetes, chronic obstructive pulmonary disease/asthma, and coronary artery disease, using the Patient Health Questionnaire-9 (PHQ-9). Two hundred and thirty-one elderly patients with chronic physical diseases were recruited consecutively from a university-affiliated general hospital in South Korea. Greater severities of all 9 depressive symptoms in the PHQ-9 were presented in those with depressive disorder rather than those without depressive disorder. A binary logistic regression modeling presented that little interest [adjusted odds ratio (aOR)=4.648, p<0.001], reduced/increased sleep (aOR=3.269, p<0.001), psychomotor retardation/agitation (aOR=2.243, p=0.004), and concentration problem (aOR=16.116, p<0.001) were independently associated with increased likelihood of having depressive disorder. Receiver operating characteristics (ROC) curve analysis presented that the optimal cut-off value of score on the items for little interest, reduced/increased sleep, psychomotor retardation/agitation and concentration problem (PHQ-9) for detecting depressive disorder was 4 with 61.9% of sensitivity and 91.5% of specificity [area under curve (AUC)=0.937, p<0.001]. Our findings suggested that the diagnostic weighting of little interest, reduced/increased sleep, psychomotor retardation/agitation, and concentration problem is needed to detect depressive disorder among the elderly patients with chronic physical diseases.

Parental Physical Force and Alcohol Use in Emerging Adults: Mediation by Psychological Problems.

PubMed

Pollard, Mary Ward; McKinney, Cliff

2016-07-01

Research has indicated that negative parenting practices, such as physical punishment, are associated with negative outcomes in children. These negative outcomes can present during childhood and during emerging adulthood. One negative consequence can be excessive alcohol use, a problematic outcome with its own myriad consequences. The goal of the current study was to examine the effects of parental physical force on emerging adult functioning, specifically alcohol and psychological problems. A sample of 488 young adults completed questionnaires on current perceptions related to alcohol-related problems, physical and psychological aggression by their parents experienced during the previous year, and current emotional and behavioral functioning. Results showed full mediation between paternal physical force and emerging adult alcohol problems by emerging adult psychological problems. Emerging adult psychological problems partially mediated the effect of maternal physical force on emerging adult alcohol problem. Gender did not moderate these effects. The results support existing literature suggesting that the use of parental physical force may lead to a chain reaction of problems, even during emerging adulthood. These results also reveal that emerging adults report currently receiving physical force from their parents, which brings to light a concerning lack of literature on the use of parental physical force on emerging adult children. These results advocate for positive parenting practives and efforts to teach them, even for emerging adult children. The results may also clinically suggest that paying attention to parental force in emerging adult clients could yield a better understanding of their current functioning, especially including excessive alcohol use.

Electronic collection of solved physics problems to encourage students’ active approach (not only to self study)

NASA Astrophysics Data System (ADS)

Koupilová, Zdeňka; Mandíková, Dana; Snětinová, Marie

2017-09-01

Ten years ago we started to develop a Collection of Fully Solved Problems aimed at introductory undergraduate and high school level students. The collection is specially designed to encourage students in an active approach to problem solving, e.g. to solve at least some parts of a problem on their own. Nowadays the Collection contains about 800 fully solved problems in physics in Czech and nearly 180 problems in English. It has several hundreds of unique visitors per school day. Based on user feedback, the collection is used by students mainly for their home study and by teachers as a supplementary material. The creation of the structured solution of the physics problems has proved to be a beneficial activity for prospective physics teachers (students of our department).

Maternal depression and physical health problems in early pregnancy: findings of an Australian nulliparous pregnancy cohort study.

PubMed

Perlen, Susan; Woolhouse, Hannah; Gartland, Deirdre; Brown, Stephanie J

2013-03-01

to investigate the relationship between physical health problems and depressive symptoms in early pregnancy. baseline questionnaire, prospective pregnancy cohort study. six metropolitan public maternity hospitals in Victoria, Australia. 1507 nulliparous women recruited in early pregnancy. nine per cent of women (131/1500) scored ≥ 13 on the EPDS indicating probable clinical depression in early pregnancy (mean gestation=15 weeks). The five most commonly reported physical health problems were as follows: exhaustion (86.9%), morning sickness (64.3%), back pain (45.6%), constipation (43.5%) and severe headaches or migraines (29.5%). Women scoring ≥ 13 on the EPDS reported a mean of six physical health problems compared with a mean of 3.5 among women scoring <13 on the EPDS. Women reporting five or more physical health problems had a three-fold increase in likelihood of reporting depressive symptoms (Adj OR=3.13, 95% CI 2.14-4.58) after adjusting for socio-demographic factors, including maternal age. the findings from this large multi-centre study show that women experiencing a greater number of physical health problems are at increased risk of reporting depressive symptoms in early pregnancy. early detection and support for women experiencing physical and psychological health problems in pregnancy is an important aspect of antenatal care. The extent of co-morbid physical and psychological health problems underlines the need for comprehensive primary health care as an integral component of antenatal care. Copyright © 2012 Elsevier Ltd. All rights reserved.

Epistemological beliefs of physics undergraduate and graduate students and faculty in the context of a well-structured and an ill-structured problem

NASA Astrophysics Data System (ADS)

Mercan, Fatih C.

This study examines epistemological beliefs of physics undergraduate and graduate students and faculty in the context of solving a well-structured and an ill-structured problem. The data collection consisted of a think aloud problem solving session followed by a semi-structured interview conducted with 50 participants, 10 participants at freshmen, seniors, masters, PhD, and faculty levels. The data analysis involved (a) identification of the range of beliefs about knowledge in the context of the well-structured and the ill-structured problem solving, (b) construction of a framework that unites the individual beliefs identified in each problem context under the same conceptual base, and (c) comparisons of the problem contexts and expertise level groups using the framework. The results of the comparison of the contexts of the well-structured and the ill-structured problem showed that (a) authoritative beliefs about knowledge were expressed in the well-structured problem context, (b) relativistic and religious beliefs about knowledge were expressed in the ill-structured problem context, and (c) rational, empirical, modeling beliefs about knowledge were expressed in both problem contexts. The results of the comparison of the expertise level groups showed that (a) undergraduates expressed authoritative beliefs about knowledge more than graduate students and faculty did not express authoritative beliefs, (b) faculty expressed modeling beliefs about knowledge more than graduate students and undergraduates did not express modeling beliefs, and (c) there were no differences in rational, empirical, experiential, relativistic, and religious beliefs about knowledge among the expertise level groups. As the expertise level increased the number of participants who expressed authoritative beliefs about knowledge decreased and the number of participants who expressed modeling based beliefs about knowledge increased. The results of this study implied that existing developmental and cognitive models of personal epistemology can explain personal epistemology in physics to a limited extent, however, these models cannot adequately account for the variation of epistemological beliefs across problem contexts. Modeling beliefs about knowledge emerged as a part of personal epistemology and an indicator of epistemological sophistication, which do not develop until extensive experience in the field. Based on these findings, the researcher recommended providing opportunities for practicing model construction for students.

Role of Multiple Representations in Physics Problem Solving

ERIC Educational Resources Information Center

Maries, Alexandru

2013-01-01

This thesis explores the role of multiple representations in introductory physics students' problem solving performance through several investigations. Representations can help students focus on the conceptual aspects of physics and play a major role in effective problem solving. Diagrammatic representations can play a particularly important role…

Phenomenographic Study of Students' Problem Solving Approaches in Physics

ERIC Educational Resources Information Center

Walsh, Laura N.; Howard, Robert G.; Bowe, Brian

2007-01-01

This paper describes ongoing research investigating student approaches to quantitative and qualitative problem solving in physics. This empirical study was conducted using a phenomenographic approach to analyze data from individual semistructured problem solving interviews with 22 introductory college physics students. The main result of the study…

On the predictivity of pore-scale simulations: Estimating uncertainties with multilevel Monte Carlo

NASA Astrophysics Data System (ADS)

Icardi, Matteo; Boccardo, Gianluca; Tempone, Raúl

2016-09-01

A fast method with tunable accuracy is proposed to estimate errors and uncertainties in pore-scale and Digital Rock Physics (DRP) problems. The overall predictivity of these studies can be, in fact, hindered by many factors including sample heterogeneity, computational and imaging limitations, model inadequacy and not perfectly known physical parameters. The typical objective of pore-scale studies is the estimation of macroscopic effective parameters such as permeability, effective diffusivity and hydrodynamic dispersion. However, these are often non-deterministic quantities (i.e., results obtained for specific pore-scale sample and setup are not totally reproducible by another ;equivalent; sample and setup). The stochastic nature can arise due to the multi-scale heterogeneity, the computational and experimental limitations in considering large samples, and the complexity of the physical models. These approximations, in fact, introduce an error that, being dependent on a large number of complex factors, can be modeled as random. We propose a general simulation tool, based on multilevel Monte Carlo, that can reduce drastically the computational cost needed for computing accurate statistics of effective parameters and other quantities of interest, under any of these random errors. This is, to our knowledge, the first attempt to include Uncertainty Quantification (UQ) in pore-scale physics and simulation. The method can also provide estimates of the discretization error and it is tested on three-dimensional transport problems in heterogeneous materials, where the sampling procedure is done by generation algorithms able to reproduce realistic consolidated and unconsolidated random sphere and ellipsoid packings and arrangements. A totally automatic workflow is developed in an open-source code [1], that include rigid body physics and random packing algorithms, unstructured mesh discretization, finite volume solvers, extrapolation and post-processing techniques. The proposed method can be efficiently used in many porous media applications for problems such as stochastic homogenization/upscaling, propagation of uncertainty from microscopic fluid and rock properties to macro-scale parameters, robust estimation of Representative Elementary Volume size for arbitrary physics.

Research Projects in Physics: A Mechanism for Teaching Ill-Structured Problem Solving

NASA Astrophysics Data System (ADS)

Milbourne, Jeff; Bennett, Jonathan

2017-10-01

Physics education research has a tradition of studying problem solving, exploring themes such as physical intuition and differences between expert and novice problem solvers. However, most of this work has focused on traditional, or well-structured, problems, similar to what might appear in a textbook. Less work has been done with open-ended, or ill-structured, problems, similar to the types of problems students might face in their professional lives. Given the national discourse on educational system reform aligned with 21st century skills, including problem solving, it is critical to provide educational experiences that help students learn to solve all types of problems, including ill-structured problems.

Influence of Peers and Friends on Children’s and Adolescents’ Eating and Activity Behaviors

PubMed Central

Salvy, Sarah-Jeanne; de la Haye, Kayla; Bowker, Julie C.; Hermans, Roel C.J.

2012-01-01

Obesity during childhood and adolescence is a growing problem in the United States, Canada, and around the world that leads to significant physical, psychological, and social consequences. Peer experiences have been theoretically and empirically related to the “Big Two” contributors to the obesity epidemic, unhealthy eating and physical inactivity [1]. In this article, we synthesize the empirical literature on the influence of peers and friends on youth’s eating and physical activity. Limitations and issues in the theoretical and empirical literatures are also discussed, along with future research directions. In conclusion, we argue that the involvement of children’s and adolescents’ peer networks in prevention and intervention efforts may be critical for promoting and maintaining positive behavioral health trajectories. However, further theoretical and empirical work is needed to better understand the specific mechanisms underlying the effects of peers on youth’s eating and physical activity. PMID:22480733

Victimization, Smoking, and Chronic Physical Health Problems Among Sexual Minority Women

PubMed Central

Simoni, Jane M.

2014-01-01

Background Sexual minority women (SMW) have been shown to be at increased risk for abuse, smoking, and chronic physical health problems compared with heterosexual women. In the general population, abuse and smoking are associated with physical health problems. However, there has been little research on their associations among SMW. Purpose The current study examined a mediational model of abuse, smoking, and self-reported physical health conditions in a national sample of SMW. Methods Participants (N=1,224) were recruited via the Internet and completed measures of childhood trauma, adult sexual assault, smoking, body mass index, and chronic medical conditions. Results Structural equation modeling demonstrated that childhood abuse was associated with adult sexual assault, smoking, and physical health problems, but smoking was not a significant mediator. Conclusions The results highlight the impact of childhood abuse on physical health problems among SMW and the need to examine other health behaviors that may mediate this relation. PMID:21735343

The Effects of Race, Ethnicity, and Mood/Anxiety Disorders on the Chronic Physical Health Conditions of Men From a National Sample

PubMed Central

Johnson-Lawrence, Vicki; Griffith, Derek M.; Watkins, Daphne C.

2013-01-01

Racial/ethnic differences in health are evident among men. Previous work suggests associations between mental and physical health but few studies have examined how mood/anxiety disorders and chronic physical health conditions covary by age, race, and ethnicity among men. Using data from 1,277 African American, 629 Caribbean Black, and 371 non-Hispanic White men from the National Survey of American Life, we examined associations between race/ethnicity and experiencing one or more chronic physical health conditions in logistic regression models stratified by age and 12-month mood/anxiety disorder status. Among men <45 years without mood/anxiety disorders, Caribbean Blacks had lower odds of chronic physical health conditions than Whites. Among men aged 45+ years with mood/anxiety disorders, African Americans had greater odds of chronic physical health conditions than Whites. Future studies should explore the underlying causes of such variation and how studying mental and chronic physical health problems together may help identify mechanisms that underlie racial disparities in life expectancy among men. PMID:23609347

Vibroacoustic optimization using a statistical energy analysis model

NASA Astrophysics Data System (ADS)

Culla, Antonio; D`Ambrogio, Walter; Fregolent, Annalisa; Milana, Silvia

2016-08-01

In this paper, an optimization technique for medium-high frequency dynamic problems based on Statistical Energy Analysis (SEA) method is presented. Using a SEA model, the subsystem energies are controlled by internal loss factors (ILF) and coupling loss factors (CLF), which in turn depend on the physical parameters of the subsystems. A preliminary sensitivity analysis of subsystem energy to CLF's is performed to select CLF's that are most effective on subsystem energies. Since the injected power depends not only on the external loads but on the physical parameters of the subsystems as well, it must be taken into account under certain conditions. This is accomplished in the optimization procedure, where approximate relationships between CLF's, injected power and physical parameters are derived. The approach is applied on a typical aeronautical structure: the cabin of a helicopter.

DAWN (Design Assistant Workstation) for advanced physical-chemical life support systems

NASA Technical Reports Server (NTRS)

Rudokas, Mary R.; Cantwell, Elizabeth R.; Robinson, Peter I.; Shenk, Timothy W.

1989-01-01

This paper reports the results of a project supported by the National Aeronautics and Space Administration, Office of Aeronautics and Space Technology (NASA-OAST) under the Advanced Life Support Development Program. It is an initial attempt to integrate artificial intelligence techniques (via expert systems) with conventional quantitative modeling tools for advanced physical-chemical life support systems. The addition of artificial intelligence techniques will assist the designer in the definition and simulation of loosely/well-defined life support processes/problems as well as assist in the capture of design knowledge, both quantitative and qualitative. Expert system and conventional modeling tools are integrated to provide a design workstation that assists the engineer/scientist in creating, evaluating, documenting and optimizing physical-chemical life support systems for short-term and extended duration missions.

Physics of the inner heliosphere: Mechanisms, models and observational signatures

NASA Technical Reports Server (NTRS)

Withbroe, George L.

1987-01-01

Selected problems concerned with the important physical processes that occur in the corona and solar wind acceleration region, particularly time dependent phenomena were studied. Both the physics of the phenomena and the resultant effects on observational signatures, particularly spectroscopic signatures were also studied. Phenomena under study include: wave motions, particularly Alfven and fast mode waves; the formation of standing shocks in the inner heliosphere as a result of momentum and/or heat addition to the wind; and coronal transient phenomena where momentum and/or heat are deposited in the corona to produce transient plasma heating and/or mass ejection. The development of theoretical models for the inner heliosphere, the theoretical investigation of spectroscopic plasma diagnostics for this region, and the analysis of existing skylab and other relevant data are also included.

Irrelevance in Problem Solving

NASA Technical Reports Server (NTRS)

Levy, Alon Y.

1992-01-01

The notion of irrelevance underlies many different works in AI, such as detecting redundant facts, creating abstraction hierarchies and reformulation and modeling physical devices. However, in order to design problem solvers that exploit the notion of irrelevance, either by automatically detecting irrelevance or by being given knowledge about irrelevance, a formal treatment of the notion is required. In this paper we present a general framework for analyzing irrelevance. We discuss several properties of irrelevance and show how they vary in a space of definitions outlined by the framework. We show how irrelevance claims can be used to justify the creation of abstractions thereby suggesting a new view on the work on abstraction.

Screening for Physical Problems in Classrooms for Severely Handicapped Students.

ERIC Educational Resources Information Center

Dever, Richard; Knapczyk, Dennis

1980-01-01

The authors present a screening device with which teachers of severely handicapped students may detect the presence of a physical problem. The screening approach covers vision, auditory problems, seizures, orthopedic problems, and pain. (CL)

[Frequency and consequences of financial problems in patients undergoing outpatient psychosomatic treatment].

PubMed

Wagner, Stefanie; Münster, Eva; Beutel, Manfred E

2010-01-01

About seven million people in Germany are affected by overindebtedness and insolvency. Being severely in debt is a very stressful situation that can result in social marginalisation, reducted overall activity, and physical and mental illness. The present study investigated the frequency of financial problems and their effects on physical and mental disorders at a university psychosomatic clinic. The study included a total of 659 patients. Their mental status was assessed with the Symptom Checklist (SCL-90-R), their physical status with the Gießener Beschwerdebogen (GBB). 37 percent of the subjects reported experiencing financial problems. We found that subjects with financial problems reported more physical and mental disorders than those without financial problems. Furthermore, therapists more often recommended that patients with financial problems receive inpatient therapy than patients without financial problems. The study suggests that financial problems should be included in any anamnesis, therapeutic recommendation, and actual therapy of patients in psychosomatic treatment.

Secure Distributed Detection under Energy Constraint in IoT-Oriented Sensor Networks.

PubMed

Zhang, Guomei; Sun, Hao

2016-12-16

We study the secure distributed detection problems under energy constraint for IoT-oriented sensor networks. The conventional channel-aware encryption (CAE) is an efficient physical-layer secure distributed detection scheme in light of its energy efficiency, good scalability and robustness over diverse eavesdropping scenarios. However, in the CAE scheme, it remains an open problem of how to optimize the key thresholds for the estimated channel gain, which are used to determine the sensor's reporting action. Moreover, the CAE scheme does not jointly consider the accuracy of local detection results in determining whether to stay dormant for a sensor. To solve these problems, we first analyze the error probability and derive the optimal thresholds in the CAE scheme under a specified energy constraint. These results build a convenient mathematic framework for our further innovative design. Under this framework, we propose a hybrid secure distributed detection scheme. Our proposal can satisfy the energy constraint by keeping some sensors inactive according to the local detection confidence level, which is characterized by likelihood ratio. In the meanwhile, the security is guaranteed through randomly flipping the local decisions forwarded to the fusion center based on the channel amplitude. We further optimize the key parameters of our hybrid scheme, including two local decision thresholds and one channel comparison threshold. Performance evaluation results demonstrate that our hybrid scheme outperforms the CAE under stringent energy constraints, especially in the high signal-to-noise ratio scenario, while the security is still assured.

Secure Distributed Detection under Energy Constraint in IoT-Oriented Sensor Networks

PubMed Central

Zhang, Guomei; Sun, Hao

2016-01-01

We study the secure distributed detection problems under energy constraint for IoT-oriented sensor networks. The conventional channel-aware encryption (CAE) is an efficient physical-layer secure distributed detection scheme in light of its energy efficiency, good scalability and robustness over diverse eavesdropping scenarios. However, in the CAE scheme, it remains an open problem of how to optimize the key thresholds for the estimated channel gain, which are used to determine the sensor’s reporting action. Moreover, the CAE scheme does not jointly consider the accuracy of local detection results in determining whether to stay dormant for a sensor. To solve these problems, we first analyze the error probability and derive the optimal thresholds in the CAE scheme under a specified energy constraint. These results build a convenient mathematic framework for our further innovative design. Under this framework, we propose a hybrid secure distributed detection scheme. Our proposal can satisfy the energy constraint by keeping some sensors inactive according to the local detection confidence level, which is characterized by likelihood ratio. In the meanwhile, the security is guaranteed through randomly flipping the local decisions forwarded to the fusion center based on the channel amplitude. We further optimize the key parameters of our hybrid scheme, including two local decision thresholds and one channel comparison threshold. Performance evaluation results demonstrate that our hybrid scheme outperforms the CAE under stringent energy constraints, especially in the high signal-to-noise ratio scenario, while the security is still assured. PMID:27999282

Get Real!--Physically Reasonable Values for Teaching Electrostatics

ERIC Educational Resources Information Center

Morse, Robert A.

2016-01-01

Students get a sense of realistic values for physical situations from texts, but more importantly from solving problems. Therefore, problems should use realistic values for quantities to provide needed practice. Unfortunately, some problems on tests and in textbooks do not use realistic values. Physical situations in electrostatics seem to be…

GRIPs (Group Investigation Problems) for Introductory Physics

NASA Astrophysics Data System (ADS)

Moore, Thomas A.

2006-12-01

GRIPs lie somewhere between homework problems and simple labs: they are open-ended questions that require a mixture of problem-solving skills and hands-on experimentation to solve practical puzzles involving simple physical objects. In this talk, I will describe three GRIPs that I developed for a first-semester introductory calculus-based physics course based on the "Six Ideas That Shaped Physics" text. I will discuss the design of the three GRIPs we used this past fall, our experience in working with students on these problems, and students' response as reported on course evaluations.

Parameter Estimation in Atmospheric Data Sets

NASA Technical Reports Server (NTRS)

Wenig, Mark; Colarco, Peter

2004-01-01

In this study the structure tensor technique is used to estimate dynamical parameters in atmospheric data sets. The structure tensor is a common tool for estimating motion in image sequences. This technique can be extended to estimate other dynamical parameters such as diffusion constants or exponential decay rates. A general mathematical framework was developed for the direct estimation of the physical parameters that govern the underlying processes from image sequences. This estimation technique can be adapted to the specific physical problem under investigation, so it can be used in a variety of applications in trace gas, aerosol, and cloud remote sensing. As a test scenario this technique will be applied to modeled dust data. In this case vertically integrated dust concentrations were used to derive wind information. Those results can be compared to the wind vector fields which served as input to the model. Based on this analysis, a method to compute atmospheric data parameter fields will be presented. .

Caustic Singularities Of High-Gain, Dual-Shaped Reflectors

NASA Technical Reports Server (NTRS)

Galindo, Victor; Veruttipong, Thavath W.; Imbriale, William A.; Rengarajan, Sambiam

1991-01-01

Report presents study of some sources of error in analysis, by geometric theory of diffraction (GTD), of performance of high-gain, dual-shaped antenna reflector. Study probes into underlying analytic causes of singularity, with view toward devising and testing practical methods to avoid problems caused by singularity. Hybrid physical optics (PO) approach used to study near-field spillover or noise-temperature characteristics of high-gain relector antenna efficiently and accurately. Report illustrates this approach and underlying principles by presenting numerical results, for both offset and symmetrical reflector systems, computed by GTD, PO, and PO/GO methods.

Supporting the Health of College Solo Singers: The Relationship of Positive Emotions and Stress to Changes in Salivary IgA and Cortisol during Singing

ERIC Educational Resources Information Center

Beck, Robert J.; Gottfried, Terry L.; Hall, David J.; Cisler, Caitlin A.; Bozeman, Kenneth W.

2006-01-01

Singers appear to experience health benefits from singing, but their art makes physical demands that may leave them prone to health problems. The study sought to measure singers' immunocompetence under practice and performance conditions. Salivary IgA and cortisol measurements were assayed from multiple pre-post saliva samples obtained from 10…

On the theory of evolution of particulate systems

NASA Astrophysics Data System (ADS)

Buyevich, Yuri A.; Alexandrov, Dmitri V.

2017-04-01

An analytical method for the description of particulate systems at sufficiently long times is developed. This method allows us to obtain very simple analytical expressions for the particle distribution function. The method under consideration can be applied to a number of practically important problems including evaporation of a polydisperse mist, dissolution of dispersed solids, combustion of dispersed propellants, physical and chemical transformation of powders and phase transitions in metastable materials.

Applications of Massive Mathematical Computations

DTIC Science & Technology

1990-04-01

particles from the first principles of QCD . This problem is under intensive numerical study 11-6 using special purpose parallel supercomputers in...several places around the world. The method used here is the Monte Carlo integration for a fixed 3-D plus time lattices . Reliable results are still years...mathematical and theoretical physics, but its most promising applications are in the numerical realization of QCD computations. Our programs for the solution

Physical investigation on silver-water nanofluid natural convection for an F-shaped cavity under the magnetic field effects

NASA Astrophysics Data System (ADS)

Yadollahi, A.; Khalesidoost, A.; Kasaeipoor, A.; Hatami, M.; Jing, D.

2017-08-01

The effects of a magnetic field on a free convection regime of silver-water nanofluid are investigated. The considered geometry is an F-shaped cavity under the influence of a constant magnetic field. The left vertical walls temperature is Th, while the middle and right walls are at a constant temperature Tc, and the other walls are insulated. A FORTRAN program is developed for the numerical simulation of the considered problem. The governing equations are solved using the FVM with the SIMPLE algorithm. The effect of important physical parameters such as the Rayleigh number, the Hartmann number, AR and φ on the problem are discussed in detail. We have concluded that the increase in the Hartmann number causes a decrease in vertical velocity and heat transfer. By increasing the Rayleigh number, the influence of the Hartmann number will be increased. An increase in the dimensional ratio of the cavity causes a decrease in the Nusselt number except in AR = 0.4. The AR has the maximum impact on the local Nusselt number, at the bottom of the hot wall. The effect of the dimensional ratio of the cavity on the Nusselt number is reversed on top of the wall. The maximum value of the Nusselt number is observed at AR = 0.4.

Scalable Methods for Eulerian-Lagrangian Simulation Applied to Compressible Multiphase Flows

NASA Astrophysics Data System (ADS)

Zwick, David; Hackl, Jason; Balachandar, S.

2017-11-01

Multiphase flows can be found in countless areas of physics and engineering. Many of these flows can be classified as dispersed two-phase flows, meaning that there are solid particles dispersed in a continuous fluid phase. A common technique for simulating such flow is the Eulerian-Lagrangian method. While useful, this method can suffer from scaling issues on larger problem sizes that are typical of many realistic geometries. Here we present scalable techniques for Eulerian-Lagrangian simulations and apply it to the simulation of a particle bed subjected to expansion waves in a shock tube. The results show that the methods presented here are viable for simulation of larger problems on modern supercomputers. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1315138. This work was supported in part by the U.S. Department of Energy under Contract No. DE-NA0002378.

A frequentist approach to computer model calibration

DOE PAGES

Wong, Raymond K. W.; Storlie, Curtis Byron; Lee, Thomas C. M.

2016-05-05

The paper considers the computer model calibration problem and provides a general frequentist solution. Under the framework proposed, the data model is semiparametric with a non-parametric discrepancy function which accounts for any discrepancy between physical reality and the computer model. In an attempt to solve a fundamentally important (but often ignored) identifiability issue between the computer model parameters and the discrepancy function, the paper proposes a new and identifiable parameterization of the calibration problem. It also develops a two-step procedure for estimating all the relevant quantities under the new parameterization. This estimation procedure is shown to enjoy excellent rates ofmore » convergence and can be straightforwardly implemented with existing software. For uncertainty quantification, bootstrapping is adopted to construct confidence regions for the quantities of interest. As a result, the practical performance of the methodology is illustrated through simulation examples and an application to a computational fluid dynamics model.« less

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

Wong, Raymond K. W.; Storlie, Curtis Byron; Lee, Thomas C. M.

The paper considers the computer model calibration problem and provides a general frequentist solution. Under the framework proposed, the data model is semiparametric with a non-parametric discrepancy function which accounts for any discrepancy between physical reality and the computer model. In an attempt to solve a fundamentally important (but often ignored) identifiability issue between the computer model parameters and the discrepancy function, the paper proposes a new and identifiable parameterization of the calibration problem. It also develops a two-step procedure for estimating all the relevant quantities under the new parameterization. This estimation procedure is shown to enjoy excellent rates ofmore » convergence and can be straightforwardly implemented with existing software. For uncertainty quantification, bootstrapping is adopted to construct confidence regions for the quantities of interest. As a result, the practical performance of the methodology is illustrated through simulation examples and an application to a computational fluid dynamics model.« less

Developing authentic problems through lived experiences in nature

NASA Astrophysics Data System (ADS)

Gürel, Zeynep

2017-02-01

This study's main objective is to develop a theoretical and ontological basis for experimentation in contact with the real life, oriented to physics education. Physics is built upon the observation of nature, where our experience provides opportunity to deal with science in natural environment to those learners who have background in the very basics and essentials of physics. Physics in Nature course includes visiting and camping experiences situated in nature and organizing camp with educational purposes. The course has been integrated with indoor and outdoor settings interactively and the authentic problems, which have been taken from outdoor settings, have been brought into the class without well-defined structure (Ill-structured problems). Within the period of ten years, there were plethora of events and problems that would provide sufficient material for many researchers. Because every problem is an event and has a story. The philosophical event concept of Deleuze and Guattari has been used in the events of Physics in Nature courses. Post-qualitative research methodology has been used in order to put forward how to construct the relation between physics and nature and become the main problem in the physics in nature, thereby it has been the basis of the course and our academic research

Physical health problems in adults with Prader-Willi syndrome.

PubMed

Sinnema, Margje; Maaskant, Marian A; van Schrojenstein Lantman-de Valk, Henny M J; van Nieuwpoort, I Caroline; Drent, Madeleine L; Curfs, Leopold M G; Schrander-Stumpel, Constance T R M

2011-09-01

Prader-Willi syndrome (PWS) is a genetic disorder which is characterized by severe hypotonia and feeding problems in early infancy. In later childhood and adolescence, this is followed by hyperphagia and extreme obesity if the diet is not strictly controlled. Data on physical health problems in adults with PWS are scarce. We report on the prevalence of physical health problems in a Dutch cohort of adults with PWS in relation to age, BMI, and genetic subtype. Participants (n = 102) were retrieved via the Dutch Prader-Willi Parent Association and through physicians specializing in persons with intellectual disabilities (ID). Details regarding physical health problem spanning the participants' lifespan were collected from caretakers through semi-structured interviews. Cardiovascular problems included diabetes mellitus, hypertension, and cerebrovascular accidents. Respiratory infections were frequent in adulthood. In males, cryptorchidism was almost universal, for which 28/48 males had a history of surgery, mostly orchidopexy. None of the women had a regular menstrual cycle. Sixteen individuals had a diagnosis of osteoporosis. Spinal deformation, hip dysplasia, and foot abnormalities were common. Skinpicking, leg edema, and erysipelas were frequent dermatological problems. The findings in our group support the notion that the prevalence of physical health problems is underestimated. This underscores the importance of developing monitoring programs which would help to recognize physical health problems at an early stage. Copyright © 2011 Wiley-Liss, Inc.

Assessing student written problem solutions: A problem-solving rubric with application to introductory physics

NASA Astrophysics Data System (ADS)

Docktor, Jennifer L.; Dornfeld, Jay; Frodermann, Evan; Heller, Kenneth; Hsu, Leonardo; Jackson, Koblar Alan; Mason, Andrew; Ryan, Qing X.; Yang, Jie

2016-06-01

Problem solving is a complex process valuable in everyday life and crucial for learning in the STEM fields. To support the development of problem-solving skills it is important for researchers and curriculum developers to have practical tools that can measure the difference between novice and expert problem-solving performance in authentic classroom work. It is also useful if such tools can be employed by instructors to guide their pedagogy. We describe the design, development, and testing of a simple rubric to assess written solutions to problems given in undergraduate introductory physics courses. In particular, we present evidence for the validity, reliability, and utility of the instrument. The rubric identifies five general problem-solving processes and defines the criteria to attain a score in each: organizing problem information into a Useful Description, selecting appropriate principles (Physics Approach), applying those principles to the specific conditions in the problem (Specific Application of Physics), using Mathematical Procedures appropriately, and displaying evidence of an organized reasoning pattern (Logical Progression).

Nicholas Metropolis Award Talk for Outstanding Doctoral Thesis Work in Computational Physics: Computational biophysics and multiscale modeling of blood cells and blood flow in health and disease

NASA Astrophysics Data System (ADS)

Fedosov, Dmitry

2011-03-01

Computational biophysics is a large and rapidly growing area of computational physics. In this talk, we will focus on a number of biophysical problems related to blood cells and blood flow in health and disease. Blood flow plays a fundamental role in a wide range of physiological processes and pathologies in the organism. To understand and, if necessary, manipulate the course of these processes it is essential to investigate blood flow under realistic conditions including deformability of blood cells, their interactions, and behavior in the complex microvascular network. Using a multiscale cell model we are able to accurately capture red blood cell mechanics, rheology, and dynamics in agreement with a number of single cell experiments. Further, this validated model yields accurate predictions of the blood rheological properties, cell migration, cell-free layer, and hemodynamic resistance in microvessels. In addition, we investigate blood related changes in malaria, which include a considerable stiffening of red blood cells and their cytoadherence to endothelium. For these biophysical problems computational modeling is able to provide new physical insights and capabilities for quantitative predictions of blood flow in health and disease.

The roles of emotional competence and social problem-solving in the relationship between physical abuse and adolescent suicidal ideation in China.

PubMed

Kwok, Sylvia Y C L; Yeung, Jerf W K; Low, Andrew Y T; Lo, Herman H M; Tam, Cherry H L

2015-06-01

The study investigated the relationship among physical abuse, positive psychological factors including emotional competence and social problem-solving, and suicidal ideation among adolescents in China. The possible moderating effects of emotional competence and social problem-solving in the association between physical abuse and adolescent suicidal ideation were also studied. A cross-sectional survey employing convenience sampling was conducted and self-administered questionnaires were collected from 527 adolescents with mean age of 14 years from the schools in Shanghai. Results showed that physical abuse was significantly and positively related to suicidal ideation in both male and female adolescents. Emotional competence was not found to be significantly associated with adolescent suicidal ideation, but rational problem-solving, a sub-scale of social problem-solving, was shown to be significantly and negatively associated with suicidal ideation for males, but not for females. However, emotional competence and rational problem-solving were shown to be a significant and a marginally significant moderator in the relationship between physical abuse and suicidal ideation in females respectively, but not in males. High rational problem-solving buffered the negative impact of physical abuse on suicidal ideation for females. Interestingly, females with higher empathy and who reported being physically abused by their parents have higher suicidal ideation. Findings are discussed and implications are stated. It is suggested to change the attitudes of parents on the concept of physical abuse, guide them on appropriate attitudes, knowledge and skills in parenting, and enhance adolescents' skills in rational problem-solving. Copyright © 2015 Elsevier Ltd. All rights reserved.

Numerical simulation of phase transition problems with explicit interface tracking

DOE PAGES

Hu, Yijing; Shi, Qiangqiang; de Almeida, Valmor F.; ...

2015-12-19

Phase change is ubiquitous in nature and industrial processes. Started from the Stefan problem, it is a topic with a long history in applied mathematics and sciences and continues to generate outstanding mathematical problems. For instance, the explicit tracking of the Gibbs dividing surface between phases is still a grand challenge. Our work has been motivated by such challenge and here we report on progress made in solving the governing equations of continuum transport in the presence of a moving interface by the front tracking method. The most pressing issue is the accounting of topological changes suffered by the interfacemore » between phases wherein break up and/or merge takes place. The underlying physics of topological changes require the incorporation of space-time subscales not at reach at the moment. Therefore we use heuristic geometrical arguments to reconnect phases in space. This heuristic approach provides new insight in various applications and it is extensible to include subscale physics and chemistry in the future. We demonstrate the method on applications such as simulating freezing, melting, dissolution, and precipitation. The later examples also include the coupling of the phase transition solution with the Navier-Stokes equations for the effect of flow convection.« less

Harnessing the Bethe free energy†

PubMed Central

Bapst, Victor

2016-01-01

ABSTRACT A wide class of problems in combinatorics, computer science and physics can be described along the following lines. There are a large number of variables ranging over a finite domain that interact through constraints that each bind a few variables and either encourage or discourage certain value combinations. Examples include the k‐SAT problem or the Ising model. Such models naturally induce a Gibbs measure on the set of assignments, which is characterised by its partition function. The present paper deals with the partition function of problems where the interactions between variables and constraints are induced by a sparse random (hyper)graph. According to physics predictions, a generic recipe called the “replica symmetric cavity method” yields the correct value of the partition function if the underlying model enjoys certain properties [Krzkala et al., PNAS (2007) 10318–10323]. Guided by this conjecture, we prove general sufficient conditions for the success of the cavity method. The proofs are based on a “regularity lemma” for probability measures on sets of the form Ωn for a finite Ω and a large n that may be of independent interest. © 2016 Wiley Periodicals, Inc. Random Struct. Alg., 49, 694–741, 2016 PMID:28035178

Thinking in Terms of Sensors: Personification of Self as an Object in Physics Problem Solving

ERIC Educational Resources Information Center

Tabor-Morris, A. E.

2015-01-01

How can physics teachers help students develop consistent problem solving techniques for both simple and complicated physics problems, such as those that encompass objects undergoing multiple forces (mechanical or electrical) as individually portrayed in free-body diagrams and/or phenomenon involving multiple objects, such as Doppler effect…

Effect of Scaffolding on Helping Introductory Physics Students Solve Quantitative Problems Involving Strong Alternative Conceptions

ERIC Educational Resources Information Center

Lin, Shih-Yin; Singh, Chandralekha

2015-01-01

It is well known that introductory physics students often have alternative conceptions that are inconsistent with established physical principles and concepts. Invoking alternative conceptions in the quantitative problem-solving process can derail the entire process. In order to help students solve quantitative problems involving strong…

Relationships between Undergraduates' Argumentation Skills, Conceptual Quality of Problem Solutions, and Problem Solving Strategies in Introductory Physics

ERIC Educational Resources Information Center

Rebello, Carina M.

2012-01-01

This study explored the effects of alternative forms of argumentation on undergraduates' physics solutions in introductory calculus-based physics. A two-phase concurrent mixed methods design was employed to investigate relationships between undergraduates' written argumentation abilities, conceptual quality of problem solutions, as well…

Analytical Derivation: An Epistemic Game for Solving Mathematically Based Physics Problems

ERIC Educational Resources Information Center

Bajracharya, Rabindra R.; Thompson, John R.

2016-01-01

Problem solving, which often involves multiple steps, is an integral part of physics learning and teaching. Using the perspective of the epistemic game, we documented a specific game that is commonly pursued by students while solving mathematically based physics problems: the "analytical derivation" game. This game involves deriving an…

Students Problem-Solving Difficulties and Implications in Physics: An Empirical Study on Influencing Factors

ERIC Educational Resources Information Center

Reddy, M. Vijaya Bhaskara; Panacharoensawad, Buncha

2017-01-01

In twenty first century, abundant innovative tools have been identified by the researchers to evaluate the conceptual understandings, problem solving, beliefs and attitudes about physics. Nevertheless, lacking of wide variety of evaluation instruments with respect to problem solving in physics. It indicates that the complexity of the domain fields…

The stability issues in problems of mathematical modeling

NASA Astrophysics Data System (ADS)

Mokin, A. Yu.; Savenkova, N. P.; Udovichenko, N. S.

2018-03-01

In the paper it is briefly considered various aspects of stability concepts, which are used in physics, mathematics and numerical methods of solution. The interrelation between these concepts is described, the questions of preliminary stability research before the numerical solution of the problem and the correctness of the mathematical statement of the physical problem are discussed. Examples of concrete mathematical statements of individual physical problems are given: a nonlocal problem for the heat equation, the Korteweg-de Fries equation with boundary conditions at infinity, the sine-Gordon equation, the problem of propagation of femtosecond light pulses in an area with a cubic nonlinearity.

Medicine and patriarchal violence: the social construction of a "private" event.

PubMed

Stark, E; Flitcraft, A; Frazier, W

1979-01-01

Our objectives are to describe the pattern of abuse associated with battering and to evaluate the contribution of the medical system and of broader social forces to its emergence. A pilot study of 481 women who used the emergency service of a large metropolitan hospital in the U.S. shows that battering includes a history of self-abuse and psychosocial problems, as well as repeated and escalating physical injury. In addition, although the number of battered women using the service is 10 times higher than medical personnel identify, the pattern of abuse that constitutes battering emerges only after its initial effects are presented and in conjunction with specific medical intervnetions and referrals. Examination of intervention and referral patterns suggests a staging process by which battering is socially constructed. At first, the physical trauma associated with abuse is medicated symptomatically. But the patient's persistence, the failure of the cure, and the incongruity between her problems and available medical explanations lead the provider to label the abused woman in ways that suggest she is personally responsible for her victimization. Although secondary problems such as depression, drug abuse, suicide attempts, or alcoholism derive as much from the intervention strategy adopted as from physical assault or psychopathology, they are treated as the primary problems at psychiatric and social service referral points where family maintenance is often the therapeutic goal. One consequence of this referral strategy is the stabilization of "violent families" in ways that virtually insure women will be abused in systematic and arbitrary ways. The use of patriarchal logic by medical providers ostensibly responding to physical trauma has less to do with individual "sexism" than with the political and economic constraints under which medicine operates as part of an "extended patriarchy." Medicine's role in battering suggests that the services function to reconstitute the "private" world of patriarchal authority, with violence if necessary, against demands to socialize the labors of love.

Multi-physics CFD simulations in engineering

NASA Astrophysics Data System (ADS)

Yamamoto, Makoto

2013-08-01

Nowadays Computational Fluid Dynamics (CFD) software is adopted as a design and analysis tool in a great number of engineering fields. We can say that single-physics CFD has been sufficiently matured in the practical point of view. The main target of existing CFD software is single-phase flows such as water and air. However, many multi-physics problems exist in engineering. Most of them consist of flow and other physics, and the interactions between different physics are very important. Obviously, multi-physics phenomena are critical in developing machines and processes. A multi-physics phenomenon seems to be very complex, and it is so difficult to be predicted by adding other physics to flow phenomenon. Therefore, multi-physics CFD techniques are still under research and development. This would be caused from the facts that processing speed of current computers is not fast enough for conducting a multi-physics simulation, and furthermore physical models except for flow physics have not been suitably established. Therefore, in near future, we have to develop various physical models and efficient CFD techniques, in order to success multi-physics simulations in engineering. In the present paper, I will describe the present states of multi-physics CFD simulations, and then show some numerical results such as ice accretion and electro-chemical machining process of a three-dimensional compressor blade which were obtained in my laboratory. Multi-physics CFD simulations would be a key technology in near future.

High-Fidelity Coupled Monte-Carlo/Thermal-Hydraulics Calculations

NASA Astrophysics Data System (ADS)

Ivanov, Aleksandar; Sanchez, Victor; Ivanov, Kostadin

2014-06-01

Monte Carlo methods have been used as reference reactor physics calculation tools worldwide. The advance in computer technology allows the calculation of detailed flux distributions in both space and energy. In most of the cases however, those calculations are done under the assumption of homogeneous material density and temperature distributions. The aim of this work is to develop a consistent methodology for providing realistic three-dimensional thermal-hydraulic distributions by coupling the in-house developed sub-channel code SUBCHANFLOW with the standard Monte-Carlo transport code MCNP. In addition to the innovative technique of on-the fly material definition, a flux-based weight-window technique has been introduced to improve both the magnitude and the distribution of the relative errors. Finally, a coupled code system for the simulation of steady-state reactor physics problems has been developed. Besides the problem of effective feedback data interchange between the codes, the treatment of temperature dependence of the continuous energy nuclear data has been investigated.

Use of the Moodle Platform to Promote an Ongoing Learning When Lecturing General Physics in the Physics, Mathematics and Electronic Engineering Programmes at the University of the Basque Country UPV/EHU

NASA Astrophysics Data System (ADS)

López, Gabriel A.; Sáenz, Jon; Leonardo, Aritz; Gurtubay, Idoia G.

2016-08-01

The Moodle platform has been used to put into practice an ongoing evaluation of the students' Physics learning process. The evaluation has been done on the frame of the course General Physics, which is lectured during the first year of the Physics, Mathematics and Electronic Engineering Programmes at the Faculty of Science and Technology of the University of the Basque Country (UPV/EHU). A test bank with more than 1000 multiple-choice questions, including conceptual and numerical problems, has been prepared. Throughout the course, the students have to answer a 10-question multiple-choice test for every one of the blocks the course is divided in and which were previously treated and worked in the theoretical lectures and problem-solving sessions. The tests are automatically corrected by Moodle, and under certain criteria, the corresponding mark is taken into account for the final mark of the course. According to the results obtained from a statistical study of the data on the student performances during the last four academic years, it has been observed that there exists an actual correlation between the marks obtained in the Moodle tests and the final mark of the course. In addition, it could be deduced that students who have passed the Moodle tests increase their possibilities of passing the course by an odds ratio close to 3.

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

Lee, Jae Sung; Lee, Shinbuhm; Noh, Tae Won

Here we report that resistive switching (RS) phenomena are reversible changes in the metastable resistance state induced by external electric fields. After discovery ~50 years ago, RS phenomena have attracted great attention due to their potential application in next-generation electrical devices. Considerable research has been performed to understand the physical mechanisms of RS and explore the feasibility and limits of such devices. There have also been several reviews on RS that attempt to explain the microscopic origins of how regions that were originally insulators can change into conductors. However, little attention has been paid to the most important factor inmore » determining resistance: how conducting local regions are interconnected. Here, we provide an overview of the underlying physics behind connectivity changes in highly conductive regions under an electric field. We first classify RS phenomena according to their characteristic current–voltage curves: unipolar, bipolar, and threshold switchings. Second, we outline the microscopic origins of RS in oxides, focusing on the roles of oxygen vacancies: the effect of concentration, the mechanisms of channel formation and rupture, and the driving forces of oxygen vacancies. Third, we review RS studies from the perspective of statistical physics to understand connectivity change in RS phenomena. We discuss percolation model approaches and the theory for the scaling behaviors of numerous transport properties observed in RS. Fourth, we review various switching-type conversion phenomena in RS: bipolar-unipolar, memory-threshold, figure-of-eight, and counter-figure-of-eight conversions. Finally, we review several related technological issues, such as improvement in high resistance fluctuations, sneak-path problems, and multilevel switching problems.« less

Problem Solving in Physics: Undergraduates' Framing, Procedures, and Decision Making

NASA Astrophysics Data System (ADS)

Modir, Bahar

In this dissertation I will start with the broad research question of what does problem solving in upper division physics look like? My focus in this study is on students' problem solving in physics theory courses. Some mathematical formalisms are common across all physics core courses such as using the process of separation of variables, doing Taylor series, or using the orthogonality properties of mathematical functions to set terms equal to zero. However, there are slight differences in their use of these mathematical formalisms across different courses, possibly because of how students map different physical systems to these processes. Thus, my first main research question aims to answer how students perform these recurring processes across upper division physics courses. I break this broad question into three particular research questions: What knowledge pieces do students use to make connections between physics and procedural math? How do students use their knowledge pieces coherently to provide reasoning strategies in estimation problems? How do students look ahead into the problem to read the information out of the physical scenario to align their use of math in physics? Building on the previous body of the literature, I will use the theory family of Knowledge in Pieces and provide evidence to expand this theoretical foundation. I will compare my study with previous studies and provide suggestions on how to generalize these theory expansions for future use. My experimental data mostly come from video-based classroom data. Students in groups of 2-4 students solve in-class problems in quantum mechanics and electromagnetic fields 1 courses collaboratively. In addition, I will analyze clinical interviews to demonstrate how a single case study student plays an epistemic game to estimate the total energy in a hurricane. My second research question is more focused on a particular instructional context. How do students frame problem solving in quantum mechanics? I will lay out a new theoretical framework based in epistemic framing that separates the problem solving space into four frames divided along two axes. The first axis models students' framing in math and physics, expanded through the second axis of conceptual problem solving and algorithmic problem solving. I use this framework to show how students navigate problem solving. Lastly, I will use this developed framework to interpret existing difficulties in quantum mechanics.

Skill Levels of Prospective Physics Teachers on Problem Posing

ERIC Educational Resources Information Center

Cildir, Sema; Sezen, Nazan

2011-01-01

Problem posing is one of the topics which the educators thoroughly accentuate. Problem posing skill is defined as an introvert activity of a student's learning. In this study, skill levels of prospective physics teachers on problem posing were determined and their views on problem posing were evaluated. To this end, prospective teachers were given…

Bi-centenary of successes of Fourier theorem: its power and limitations in optical system designs

NASA Astrophysics Data System (ADS)

Roychoudhuri, Chandrasekhar

2007-09-01

We celebrate the two hundred years of successful use of the Fourier theorem in optics. However, there is a great enigma associated with the Fourier transform integral. It is one of the most pervasively productive and useful tool of physics and optics because its foundation is based on the superposition of harmonic functions and yet we have never declared it as a principle of physics for valid reasons. And, yet there are a good number of situations where we pretend it to be equivalent to the superposition principle of physics, creating epistemological problems of enormous magnitude. The purpose of the paper is to elucidate the problems while underscoring the successes and the elegance of the Fourier theorem, which are not explicitly discussed in the literature. We will make our point by taking six major engineering fields of optics and show in each case why it works and under what restricted conditions by bringing in the relevant physics principles. The fields are (i) optical signal processing, (ii) Fourier transform spectrometry, (iii) classical spectrometry of pulsed light, (iv) coherence theory, (v) laser mode locking and (vi) pulse broadening. We underscore that mathematical Fourier frequencies, not being physical frequencies, cannot generate real physical effects on our detectors. Appreciation of this fundamental issue will open up ways to be innovative in many new optical instrument designs. We underscore the importance of always validating our design platforms based on valid physics principles (actual processes undergoing in nature) captured by an appropriate hypothesis based on diverse observations. This paper is a comprehensive view of the power and limitations of Fourier Transform by summarizing a series of SPIE conference papers presented during 2003-2007.

The Effect of New Vocabulary on Problem Solving in Novice Physics Students.

ERIC Educational Resources Information Center

Sobolewski, Stanley J.

One of the difficulties encountered by novice problem solvers in introductory physics is in the area of problem solving. It has been shown in other studies that poor problem solvers are affected by the surface aspects of the problem in contrast with more efficient problem solvers who are capable of constructing a mental model of the physical…

Examining End-of-Chapter Problems across Editions of an Introductory Calculus-Based Physics Textbook

ERIC Educational Resources Information Center

Xiao, Bin

2016-01-01

End-Of-Chapter (EOC) problems have been part of many physics education studies. Typically, only problems "localized" as relevant to a single chapter were used. This work examines how well this type of problem represents all EOC problems and whether EOC problems found in leading textbooks have changed over the past several decades. To…

Case of Two Electrostatics Problems: Can Providing a Diagram Adversely Impact Introductory Physics Students' Problem Solving Performance?

ERIC Educational Resources Information Center

Maries, Alexandru; Singh, Chandralekha

2018-01-01

Drawing appropriate diagrams is a useful problem solving heuristic that can transform a problem into a representation that is easier to exploit for solving it. One major focus while helping introductory physics students learn effective problem solving is to help them understand that drawing diagrams can facilitate problem solution. We conducted an…

Block recursive LU preconditioners for the thermally coupled incompressible inductionless MHD problem

NASA Astrophysics Data System (ADS)

Badia, Santiago; Martín, Alberto F.; Planas, Ramon

2014-10-01

The thermally coupled incompressible inductionless magnetohydrodynamics (MHD) problem models the flow of an electrically charged fluid under the influence of an external electromagnetic field with thermal coupling. This system of partial differential equations is strongly coupled and highly nonlinear for real cases of interest. Therefore, fully implicit time integration schemes are very desirable in order to capture the different physical scales of the problem at hand. However, solving the multiphysics linear systems of equations resulting from such algorithms is a very challenging task which requires efficient and scalable preconditioners. In this work, a new family of recursive block LU preconditioners is designed and tested for solving the thermally coupled inductionless MHD equations. These preconditioners are obtained after splitting the fully coupled matrix into one-physics problems for every variable (velocity, pressure, current density, electric potential and temperature) that can be optimally solved, e.g., using preconditioned domain decomposition algorithms. The main idea is to arrange the original matrix into an (arbitrary) 2 × 2 block matrix, and consider an LU preconditioner obtained by approximating the corresponding Schur complement. For every one of the diagonal blocks in the LU preconditioner, if it involves more than one type of unknowns, we proceed the same way in a recursive fashion. This approach is stated in an abstract way, and can be straightforwardly applied to other multiphysics problems. Further, we precisely explain a flexible and general software design for the code implementation of this type of preconditioners.

Sexual Minority Stress, Coping, and Physical Health Indicators.

PubMed

Flenar, Delphia J; Tucker, Carolyn M; Williams, Jaime L

2017-12-01

Sexual minorities experience higher rates of several physical health problems compared to their heterosexual counterparts. The present study uses Meyer's Minority Stress Model (Psychological Bulletin, 129(5): 674-697, 2003) to examine physical health indicators among 250 adults who identified as sexual minorities. Study hypotheses include that sexual minority stress is predictive of two physical health indicators (i.e., engagement in a health-promoting lifestyle and number of physical health problems) and that planning (i.e., problem-focused) and social support coping will partially mediate the relationship between sexual minority stress and each physical health indicator. Results showed that as level of sexual minority stress increased, engagement in a health-promoting lifestyle decreased and the number of physical health problems increased. Planning and social support coping did not mediate these relationships; however, as levels of coping increased, engagement in a health-promoting lifestyle increased. These findings have implications for researchers and healthcare professionals in their efforts to promote the physical health of sexual minorities.

Surveying college introductory physics students’ attitudes and approaches to problem solving

NASA Astrophysics Data System (ADS)

Mason, Andrew J.; Singh, Chandralekha

2016-09-01

Students’ attitudes and approaches to problem solving in physics can greatly impact their actual problem solving practices and also influence their motivation to learn and ultimately the development of expertise. We developed and validated an attitudes and approaches to problem solving (AAPS) survey and administered it to students in the introductory physics courses in a typical large research university in the US. Here, we discuss the development and validation of the survey and analysis of the student responses to the survey questions in introductory physics courses. The introductory physics students’ responses to the survey questions were also compared with those of physics faculty members and physics PhD students. We find that introductory students are in general less expert-like than the physics faculty members and PhD students. Moreover, on some AAPS survey questions, the responses of students and faculty have unexpected trends. Those trends were interpreted via individual interviews, which helped clarify reasons for those survey responses.

The Effects of Stretching Exercises during Rehearsals on String Students' Self-Reported Perceptions of Discomfort

ERIC Educational Resources Information Center

Cooper, Shelly C.; Hamann, Donald L.; Frost, Robert

2012-01-01

Musicians have recognized that physical problems often accompany playing, yet examinations of performance-related injuries and medical problems remain relatively new. The type of instrument played can affect musicians' pain-related problems as well as physical stature. The focus of this study was to determine whether physical intervention--easily…

Can Short Duration Visual Cues Influence Students' Reasoning and Eye Movements in Physics Problems?

ERIC Educational Resources Information Center

Madsen, Adrian; Rouinfar, Amy; Larson, Adam M.; Loschky, Lester C.; Rebello, N. Sanjay

2013-01-01

We investigate the effects of visual cueing on students' eye movements and reasoning on introductory physics problems with diagrams. Participants in our study were randomly assigned to either the cued or noncued conditions, which differed by whether the participants saw conceptual physics problems overlaid with dynamic visual cues. Students in the…

How Do They Solve It? An Insight into the Learner's Approach to the Mechanism of Physics Problem Solving

ERIC Educational Resources Information Center

Hegde, Balasubrahmanya; Meera, B. N.

2012-01-01

A perceived difficulty is associated with physics problem solving from a learner's viewpoint, arising out of a multitude of reasons. In this paper, we have examined the microstructure of students' thought processes during physics problem solving by combining the analysis of responses to multiple-choice questions and semistructured student…

How do classical particle-field systems become unstable? - The last physics problem that Ronald Davidson studied

NASA Astrophysics Data System (ADS)

Qin, Hong

2016-10-01

Many of the classical particle-field systems in (neutral and nonneutral) plasma physics and accelerator physics become unstable when the system parameters vary. How do these instabilities happen? It turns out, very interestingly, that all conservative systems become unstable by the same mechanism, i.e, the resonance between a positive- and a negative-action modes. And this is the only route that a stable system can become unstable. In this talk, I will use several examples in plasma physics and accelerator physics with finite and infinite degrees of freedom to illustrate the basic physical picture and the rigorous theoretical structure of the process. The features at the transition between stable and unstable regions in the parameter space are the fundamental characteristics of the underlying real Hamiltonian system and complex G-Hamiltonian system. The resonance between a positive- and a negative-action modes at the transition is the Krein collision well-known to mathematicians. Research supported by the U.S. Department of Energy (DE-AC02-09CH11466).

Physical processes in high field insulating liquid conduction

NASA Astrophysics Data System (ADS)

Mazarakis, Michael; Kiefer, Mark; Leckbee, Joshua; Anderson, Delmar; Wilkins, Frank; Obregon, Robert

2017-10-01

In the power grid transmission where a large amount of energy is transmitted to long distances, High Voltage DC (HVDC) transmission of up to 1MV becomes more attractive since is more efficient than the counterpart AC. However, two of the most difficult problems to solve are the cable connections to the high voltage power sources and their insulation from the ground. The insulating systems are usually composed of transformer oil and solid insulators. The oil behavior under HVDC is similar to that of a weak electrolyte. Its behavior under HVDC is dominated more by conductivity than dielectric constant. Space charge effects in the oil bulk near high voltage electrodes and impeded plastic insulators affect the voltage oil hold-off. We have constructed an experimental facility where we study the oil and plastic insulator behavior in an actual HVDC System. Experimental results will be presented and compared with the present understanding of the physics governing the oil behavior under very high electrical stresses. Sandia National Laboratories managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. D.O.E., NNSA under contract DE-NA-0003525.

Bereavement

MedlinePlus

... as a mental, physical, social or emotional reaction. Mental reactions can include anger, guilt, anxiety, sadness and despair. Physical reactions can include sleeping problems, changes in appetite, physical problems or illness. How long bereavement lasts can depend on how ...

Cortisol Awakening Response and Walking Speed in Older People

PubMed Central

Pulopulos, Matias M.; Puig-Perez, Sara; Hidalgo, Vanesa; Villada, Carolina; Salvador, Alicia

2016-01-01

In older people, less diurnal variability in cortisol levels has been consistently related to worse physical performance, especially to slower walking speed (WS). The cortisol awakening response (CAR) is a discrete component of the hypothalamic-pituitary-adrenal axis that has been related to several health problems, such as cardiovascular disease and/or worse performance on executive function and memory. The relationship between the CAR and physical performance in older people is poorly understood. In this study, in 86 older people (mean age = 64.42, SD = 3.93), we investigated the relationship between the CAR and WS, a commonly used measure of physical performance in the older population that has also been related to health problems, such as cardiovascular disease and executive function performance in older people. Additionally, we studied whether the relationship between the CAR and WS was independent from cortisol levels on awakening and several possible confounders. Results showed that a CAR of reduced magnitude (measured with 3 samples each day, for two consecutive days, and calculated as the area under the curve with respect to the increase), but not cortisol levels on awakening, was related to slower WS. In addition, this relationship was independent from cortisol levels on awakening. It is possible that a CAR of reduced magnitude would contribute to less diurnal cortisol variability, affecting physical performance. Additionally, it is possible that a CAR of reduced magnitude affects WS through a possible negative effect on executive function, or that the association between the CAR and WS is due to the fact that both are related to similar health problems and to changes in cognitive performance in older people. PMID:27191847

Physics-based Inverse Problem to Deduce Marine Atmospheric Boundary Layer Parameters

DTIC Science & Technology

2017-03-07

please find the Final Technical Report with SF 298 for Dr. Erin E. Hackett’s ONR grant entitled Physics-based Inverse Problem to Deduce Marine...From- To) 07/03/2017 Final Technica l Dec 2012- Dec 2016 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Physics-based Inverse Problem to Deduce Marine...SUPPLEMENTARY NOTES 14. ABSTRACT This report describes research results related to the development and implementation of an inverse problem approach for

Workplace bullying, sleep problems and leisure-time physical activity: a prospective cohort study.

PubMed

Hansen, Åse Marie; Gullander, Maria; Hogh, Annie; Persson, Roger; Kolstad, Henrik A; Willert, Morten Vejs; Bonde, Jens Peter; Kaerlev, Linda; Rugulies, Reiner; Grynderup, Matias Brødsgaard

2016-01-01

Workplace bullying is a potent stressor that may increase sleep problems. Since physical fitness improves resilience to stress, it seems plausible that recreational physical activities may moderate the association between bullying and sleep. The study aimed to examine prospectively whether (i) bullying increases the risk of sleep problems, and (ii) the association between bullying and sleep problems is moderated by leisure-time physical activity (LTPA). The study sample comprised a cohort of public and private sector employees, who were enrolled into the Work Bullying and Harassment (WBH) cohort (N=3278) or the Psychosocial Risk Factors for Stress and Mental Disease (PRISME) cohort (N=4455). We measured workplace bullying using one question that was preceded by a definition of bullying. We used the Karolinska sleep questionnaire to assess sleep problems. The number of hours per week spent on LTPA estimated the degree of physical activity. Workplace bullying at baseline (T1) was associated with awakening problems and lack of restful sleep at follow-up (T2) but not with overall sleep problems and disturbed sleep. T1-LTPA did not moderate the association between T1-workplace bullying and T2-sleep problems. We found support that workplace bullying is related to development of T2-sleep problems, but this association seems not to be modified by LTPA.

Do students benefit from drawing productive diagrams themselves while solving introductory physics problems? The case of two electrostatics problems

NASA Astrophysics Data System (ADS)

Maries, Alexandru; Singh, Chandralekha

2018-01-01

An appropriate diagram is a required element of a solution building process in physics problem solving and it can transform a given problem into a representation that is easier to exploit for solving the problem. A major focus while helping introductory physics students learn problem solving is to help them appreciate that drawing diagrams facilitates problem solving. We conducted an investigation in which two different interventions were implemented during recitation quizzes throughout the semester in a large enrolment, algebra-based introductory physics course. Students were either (1) asked to solve problems in which the diagrams were drawn for them or (2) explicitly told to draw a diagram. A comparison group was not given any instruction regarding diagrams. We developed a rubric to score the problem solving performance of students in different intervention groups. We investigated two problems involving electric field and electric force and found that students who drew productive diagrams were more successful problem solvers and that a higher level of relevant detail in a student’s diagram corresponded to a better score. We also conducted think-aloud interviews with nine students who were at the time taking an equivalent introductory algebra-based physics course in order to gain insight into how drawing diagrams affects the problem solving process. These interviews supported some of the interpretations of the quantitative results. We end by discussing instructional implications of the findings.

Anxiety Sensitivity and Cannabis Use-Related Problems: The Impact of Race

PubMed Central

Dean, Kimberlye E.; Ecker, Anthony H.; Buckner, Julia D.

2017-01-01

Background and Objectives Cannabis is the most widely used illicit substance among young adults. Anxiety sensitivity (AS; i.e., fear of anxiety-related symptoms) is positively related to coping motives for cannabis use (which are robustly positively linked to cannabis-related problems). However, AS is unrelated to cannabis use-related problems. Yet, extant studies have been conducted on primarily White samples. It may be that among Black students, AS-physical concerns (i.e., fear of physical anxiety-related sensations) are related to cannabis problems given that Black individuals are more likely than White individuals to report experiencing greater and more intense somatic symptoms when experiencing anxiety. Black individuals may rely on cannabis to cope with fear of these somatic symptoms, continuing to use despite cannabis-related problems. Methods The current study tested whether race moderated the relation between AS-physical concerns and cannabis problems among 102 (85.3% female) current cannabis using undergraduates who were either non-Hispanic Black (n= 51) or non-Hispanic White (n= 51). Results After controlling for frequency of cannabis use, income, and gender, race significantly moderated the relation between AS-physical concerns and cannabis use-related problems such that AS-physical concerns significantly predicted cannabis-related problems among Black and not White individuals. Discussion and Conclusions Findings highlight the importance of considering race in identifying psychosocial predictors of cannabis-related problems. Scientific Significance Intervention strategies for Black cannabis users may benefit from examining and targeting AS-physical concerns. PMID:28295843

Anxiety sensitivity and cannabis use-related problems: The impact of race.

PubMed

Dean, Kimberlye E; Ecker, Anthony H; Buckner, Julia D

2017-04-01

Cannabis is the most widely used illicit substance among young adults. Anxiety sensitivity (AS; ie, fear of anxiety-related symptoms) is positively related to coping motives for cannabis use (which are robustly positively linked to cannabis-related problems). However, AS is unrelated to cannabis use-related problems. Yet, extant studies have been conducted on primarily White samples. It may be that among Black students, AS-physical concerns (ie, fear of physical anxiety-related sensations) are related to cannabis problems given that Black individuals are more likely than White individuals to report experiencing greater and more intense somatic symptoms when experiencing anxiety. Black individuals may rely on cannabis to cope with fear of these somatic symptoms, continuing to use despite cannabis-related problems. The current study tested whether race moderated the relation between AS-physical concerns and cannabis problems among 102 (85.3% female) current cannabis using undergraduates who were either non-Hispanic Black (n = 51) or non-Hispanic White (n = 51). After controlling for frequency of cannabis use, income, and gender, race significantly moderated the relation between AS-physical concerns and cannabis use-related problems such that AS-physical concerns significantly predicted cannabis-related problems among Black and not White individuals. Findings highlight the importance of considering race in identifying psychosocial predictors of cannabis-related problems. Intervention strategies for Black cannabis users may benefit from examining and targeting AS-physical concerns. (Am J Addict 2017;26:209-214). © 2017 American Academy of Addiction Psychiatry.

The role of physical content in piagetian spatial tasks: Sex differences in spatial knowledge?

NASA Astrophysics Data System (ADS)

Golbeck, Susan L.

Sex-related differences on Piagetian horizontality (water level) and verticality (plumb line) tasks were examined in 64 college students. It was hypothesized that females' difficulties on these Euclidean spatial problems are due not to differences in underlying spatial competence, but rather to differences in knowledge of task specific information about the physical properties of water levels and plumb lines. This was tested by presenting subjects with the standard water level and plumb line problems and also modified problems not requiring knowledge of physical principles (i.e., drawing straight up and down or straight across lines inside tipped rectangles). While males were expected to outperform females on the standard tasks, no sex differences were expected on the modified tasks. Results of an ANOVA on scores for horizontality and verticality each showed main effects for sex and task version but failed to reveal the hypothesized interaction. However, performance on the Euclidean spatial tasks was also considered in terms of overall success versus failure. While males were more successful than females in the standard format, males and females were equally successful in the modified, nonphysical, format. Hence, college aged males and females generally do not differ in spatial competence although they may be differentially influenced by task content. Findings are discussed in terms of their implications for theory and practice. It is emphasized that science educators must be especially aware of such task influences for females so that performance deficits are not mistaken for competence deficits.

Practice makes perfect: familiarity of task determines success in solvable tasks for free-ranging dogs (Canis lupus familiaris).

PubMed

Bhattacharjee, Debottam; Dasgupta, Sandipan; Biswas, Arpita; Deheria, Jayshree; Gupta, Shreya; Nikhil Dev, N; Udell, Monique; Bhadra, Anindita

2017-07-01

Domestic dogs' (Canis lupus familiaris) socio-cognitive faculties have made them highly sensitive to human social cues. While dogs often excel at understanding human communicative gestures, they perform comparatively poorly in problem-solving and physical reasoning tasks. This difference in their behaviour could be due to the lifestyle and intense socialization, where problem solving and physical cognition are less important than social cognition. Free-ranging dogs live in human-dominated environments, not under human supervision and are less socialized. Being scavengers, they often encounter challenges where problem solving is required in order to get access to food. We tested Indian street dogs in familiar and unfamiliar independent solvable tasks and quantified their persistence and dependence on a novel human experimenter, in addition to their success in solving a task. Our results indicate that free-ranging dogs succeeded and persisted more in the familiar task as compared to the unfamiliar one. They showed negligible amount of human dependence in the familiar task, but showed prolonged gazing and considerable begging behaviour to the human experimenter in the context of the unfamiliar task. Cognitive abilities of free-ranging dogs thus play a pivotal role in determining task-associated behaviours based on familiarity. In addition to that, these dogs inherently tend to socialize with and depend on humans, even if they are strangers. Our results also illustrate free-ranging dogs' low competence at physical cognitive tasks.

Parents who hit and scream: interactive effects of verbal and severe physical aggression on clinic-referred adolescents' adjustment.

PubMed

LeRoy, Michelle; Mahoney, Annette; Boxer, Paul; Gullan, Rebecca Lakin; Fang, Qijuan

2014-05-01

The goals of this study were first, to delineate the co-occurrence of parental severe physical aggression and verbal aggression toward clinic-referred adolescents, and second, to examine the interactive effects of parental severe physical aggression and verbal aggression on adolescent externalizing and internalizing behavior problems. This research involved 239 referrals of 11- to 18-year-old youth and their dual-parent families to a non-profit, private community mental health center in a semi-rural Midwest community. Multiple informants (i.e., adolescents and mothers) were used to assess parental aggression and adolescent behavior problems. More than half of clinic-referred adolescents (51%) experienced severe physical aggression and/or high verbal aggression from one or both parents. A pattern of interactive effects of mother-to-adolescent severe physical aggression and verbal aggression on adolescent behavior problems emerged, indicating that when severe physical aggression was present, mother-to-adolescent verbal aggression was positively associated with greater adolescent behavior problems whereas when severe physical aggression was not present, the links between verbal aggression and behavior problems was no longer significant. No interactive effects were found for father-to-adolescent severe physical aggression and verbal aggression on adolescent adjustment; however, higher father-to-adolescent verbal aggression was consistently linked to behavior problems above and beyond the influence of severe physical aggression. The results of this study should promote the practice of routinely assessing clinic-referred adolescents and their parents about their experiences of verbal aggression in addition to severe physical aggression and other forms of abuse. Copyright © 2013 Elsevier Ltd. All rights reserved.

MPPhys—A many-particle simulation package for computational physics education

NASA Astrophysics Data System (ADS)

Müller, Thomas

2014-03-01

In a first course to classical mechanics elementary physical processes like elastic two-body collisions, the mass-spring model, or the gravitational two-body problem are discussed in detail. The continuation to many-body systems, however, is deferred to graduate courses although the underlying equations of motion are essentially the same and although there is a strong motivation for high-school students in particular because of the use of particle systems in computer games. The missing link between the simple and the more complex problem is a basic introduction to solve the equations of motion numerically which could be illustrated, however, by means of the Euler method. The many-particle physics simulation package MPPhys offers a platform to experiment with simple particle simulations. The aim is to give a principle idea how to implement many-particle simulations and how simulation and visualization can be combined for interactive visual explorations. Catalogue identifier: AERR_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AERR_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 111327 No. of bytes in distributed program, including test data, etc.: 608411 Distribution format: tar.gz Programming language: C++, OpenGL, GLSL, OpenCL. Computer: Linux and Windows platforms with OpenGL support. Operating system: Linux and Windows. RAM: Source Code 4.5 MB Complete package 242 MB Classification: 14, 16.9. External routines: OpenGL, OpenCL Nature of problem: Integrate N-body simulations, mass-spring models Solution method: Numerical integration of N-body-simulations, 3D-Rendering via OpenGL. Running time: Problem dependent

Gambling and physical intimate partner violence: Results from the national epidemiologic survey on alcohol and related conditions (NESARC).

PubMed

Roberts, Amanda; Landon, Jason; Sharman, Stephen; Hakes, Jahn; Suomi, Aino; Cowlishaw, Sean

2018-01-01

Links between intimate partner violence (IPV) and gambling problems are under researched in general population samples. Understanding these relationships will allow for improved identification and intervention. We investigated these relationships and sought to determine whether links were attenuated by axis I and II disorders. This study examined data from waves 1 and 2 (N = 25,631) of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC); a nationally representative survey of U.S. adults. Gambling symptoms and other psychiatric disorders were measured at wave 1 by the Alcohol Use Disorder and Associated Disability Interview Schedule-DSM-IV Version (AUDADIS-IV). Physical IPV victimization and perpetration in the last 12 months were assessed 3 years later at wave 2 using items from the Conflict Tactics Scale-R. Binary logistic regression models were used to examine associations separately for males and females. Problem gambling was associated with increased odds of both IPV perpetration for males (OR = 2.62, 95%CI = 1.22-5.60) and females (OR = 2.87, 95%CI = 1.29-6.42), and with IPV victimization for females only (OR = 2.97, 95%CI = 1.31-6.74). Results were attenuated with inclusion of axis I and axis II disorders; links between gambling and IPV were weaker than those involving other mental health conditions. There are prospective associations with gambling problems and physical IPV which have implications for identification, spontaneous disclosure, and treatment seeking. The links between gambling problems and violence are complex and should not be considered independently of co-occurring mental health and substance use disorders. (Am J Addict 2018;27:7-14). © 2017 American Academy of Addiction Psychiatry.

Discrete Element Method and its application to materials failure problem on the example of Brazilian Test

NASA Astrophysics Data System (ADS)

Klejment, Piotr; Kosmala, Alicja; Foltyn, Natalia; Dębski, Wojciech

2017-04-01

The earthquake focus is the point where a rock under external stress starts to fracture. Understanding earthquake nucleation and earthquake dynamics requires thus understanding of fracturing of brittle materials. This, however, is a continuing problem and enduring challenge to geoscience. In spite of significant progress we still do not fully understand the failure of rock materials due to extreme stress concentration in natural condition. One of the reason of this situation is that information about natural or induced seismic events is still not sufficient for precise description of physical processes in seismic foci. One of the possibility of improving this situation is using numerical simulations - a powerful tool of contemporary physics. For this reason we used an advanced implementation of the Discrete Element Method (DEM). DEM's main task is to calculate physical properties of materials which are represented as an assembly of a great number of particles interacting with each other. We analyze the possibility of using DEM for describing materials during so called Brazilian Test. Brazilian Test is a testing method to obtain the tensile strength of brittle material. One of the primary reasons for conducting such simulations is to measure macroscopic parameters of the rock sample. We would like to report our efforts of describing the fracturing process during the Brazilian Test from the microscopic point of view and give an insight into physical processes preceding materials failure.

Health after childbirth: patterns of reported postpartum morbidity from Lebanon.

PubMed

Kabakian-Khasholian, Tamar; Shayboub, Rawan; Ataya, Alexandra

2014-03-01

The postpartum period is under-researched in low and middle income countries. The scarce literature reveals heavy burden of ill health experienced in that period and under utilisation of health services. Understanding the postpartum morbidity burden and identifying the care-seeking behaviours is essential to improve service delivery. This paper examines reported postpartum morbidity, care seeking behaviour and whether postpartum morbidity is associated with method of birth. A cross sectional study of women delivering in 18 private hospitals from two regions in Lebanon was undertaken. Women in their second or third trimester of pregnancy, visiting private obstetric clinics affiliated with participating hospitals were interviewed for baseline information. Reported postpartum morbidity was assessed in an interview conducted at women's homes from 40 days up to six months postpartum. Of the 269 women recruited, physical postpartum health problems were reported by 93.6% and psychological health problems by 84.4% of women, with more health problems being reported beyond two months postpartum. Women were less likely to seek professional care for psychological health problems. Reporting postpartum health problems was not associated with method of birth. A heavy burden of postpartum morbidity is experienced by women with gaps in utilisation of relevant health services. Efforts should be directed towards the organisation and delivery of comprehensive maternity care services. Copyright © 2013 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

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.

Perceived Problem Solving, Stress, and Health among College Students

ERIC Educational Resources Information Center

Largo-Wight, Erin; Peterson, P. Michael; Chen, W. William

2005-01-01

Objective: To study the relationships among perceived problem solving, stress, and physical health. Methods: The Perceived Stress Questionnaire (PSQ), Personal Problem solving Inventory (PSI), and a stress-related physical health symptoms checklist were used to measure perceived stress, problem solving, and health among undergraduate college…

Impact of Guided Reflection with Peers on the Development of Effective Problem Solving Strategies and Physics Learning

ERIC Educational Resources Information Center

Mason, Andrew J.; Singh, Chandralekha

2016-01-01

Students must learn effective problem solving strategies in order to develop expertise in physics. Effective problem solving strategies include a conceptual analysis of the problem followed by planning of the solution, and then implementation, evaluation, and reflection upon the process. Research suggests that converting a problem from the initial…

A roadmap for optimal control: the right way to commute.

PubMed

Ross, I Michael

2005-12-01

Optimal control theory is the foundation for many problems in astrodynamics. Typical examples are trajectory design and optimization, relative motion control of distributed space systems and attitude steering. Many such problems in astrodynamics are solved by an alternative route of mathematical analysis and deep physical insight, in part because of the perception that an optimal control framework generates hard problems. Although this is indeed true of the Bellman and Pontryagin frameworks, the covector mapping principle provides a neoclassical approach that renders hard problems easy. That is, although the origins of this philosophy can be traced back to Bernoulli and Euler, it is essentially modern as a result of the strong linkage between approximation theory, set-valued analysis and computing technology. Motivated by the broad success of this approach, mission planners are now conceiving and demanding higher performance from space systems. This has resulted in new set of theoretical and computational problems. Recently, under the leadership of NASA-GRC, several workshops were held to address some of these problems. This paper outlines the theoretical issues stemming from practical problems in astrodynamics. Emphasis is placed on how it pertains to advanced mission design problems.

IMPROVED CORROSION RESISTANCE OF ALUMINA REFRACTORIES

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

John P. Hurley; Patty L. Kleven

2001-09-30

The initial objective of this project was to do a literature search to define the problems of refractory selection in the metals and glass industries. The problems fall into three categories: Economic--What do the major problems cost the industries financially? Operational--How do the major problems affect production efficiency and impact the environment? and Scientific--What are the chemical and physical mechanisms that cause the problems to occur? This report presents a summary of these problems. It was used to determine the areas in which the EERC can provide the most assistance through bench-scale and laboratory testing. The final objective of thismore » project was to design and build a bench-scale high-temperature controlled atmosphere dynamic corrosion application furnace (CADCAF). The furnace will be used to evaluate refractory test samples in the presence of flowing corrodents for extended periods, to temperatures of 1600 C under controlled atmospheres. Corrodents will include molten slag, steel, and glass. This test should prove useful for the glass and steel industries when faced with the decision of choosing the best refractory for flowing corrodent conditions.« less

A social discounting model based on Tsallis’ statistics

NASA Astrophysics Data System (ADS)

Takahashi, Taiki

2010-09-01

Social decision making (e.g. social discounting and social preferences) has been attracting attention in economics, econophysics, social physics, behavioral psychology, and neuroeconomics. This paper proposes a novel social discounting model based on the deformed algebra developed in the Tsallis’ non-extensive thermostatistics. Furthermore, it is suggested that this model can be utilized to quantify the degree of consistency in social discounting in humans and analyze the relationships between behavioral tendencies in social discounting and other-regarding economic decision making under game-theoretic conditions. Future directions in the application of the model to studies in econophysics, neuroeconomics, and social physics, as well as real-world problems such as the supply of live organ donations, are discussed.

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...

Regularizing cosmological singularities by varying physical constants

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

Dąbrowski, Mariusz P.; Marosek, Konrad, E-mail: mpdabfz@wmf.univ.szczecin.pl, E-mail: k.marosek@wmf.univ.szczecin.pl

2013-02-01

Varying physical constant cosmologies were claimed to solve standard cosmological problems such as the horizon, the flatness and the Λ-problem. In this paper, we suggest yet another possible application of these theories: solving the singularity problem. By specifying some examples we show that various cosmological singularities may be regularized provided the physical constants evolve in time in an appropriate way.

Some Learning Problems Concerning the Use of Symbolic Language in Physics.

ERIC Educational Resources Information Center

De Lozano, Silvia Ragout; Cardenas, Marta

2002-01-01

Draws the attention of teachers of basic university physics courses to student problems concerning the interpretation of the symbolic language used in physics. Reports specific difficulties found in the first physics course related to different kinds of statements expressed in the mathematical language. (Contains 15 references.) (Author/YDS)

Physics Metacognition Inventory Part Ii: Confirmatory Factor Analysis and Rasch Analysis

ERIC Educational Resources Information Center

Taasoobshirazi, Gita; Bailey, MarLynn; Farley, John

2015-01-01

The Physics Metacognition Inventory was developed to measure physics students' metacognition for problem solving. In one of our earlier studies, an exploratory factor analysis provided evidence of preliminary construct validity, revealing six components of students' metacognition when solving physics problems including knowledge of cognition,…

Development of a problem solving evaluation instrument; untangling of specific problem solving assets

NASA Astrophysics Data System (ADS)

Adams, Wendy Kristine

The purpose of my research was to produce a problem solving evaluation tool for physics. To do this it was necessary to gain a thorough understanding of how students solve problems. Although physics educators highly value problem solving and have put extensive effort into understanding successful problem solving, there is currently no efficient way to evaluate problem solving skill. Attempts have been made in the past; however, knowledge of the principles required to solve the subject problem are so absolutely critical that they completely overshadow any other skills students may use when solving a problem. The work presented here is unique because the evaluation tool removes the requirement that the student already have a grasp of physics concepts. It is also unique because I picked a wide range of people and picked a wide range of tasks for evaluation. This is an important design feature that helps make things emerge more clearly. This dissertation includes an extensive literature review of problem solving in physics, math, education and cognitive science as well as descriptions of studies involving student use of interactive computer simulations, the design and validation of a beliefs about physics survey and finally the design of the problem solving evaluation tool. I have successfully developed and validated a problem solving evaluation tool that identifies 44 separate assets (skills) necessary for solving problems. Rigorous validation studies, including work with an independent interviewer, show these assets identified by this content-free evaluation tool are the same assets that students use to solve problems in mechanics and quantum mechanics. Understanding this set of component assets will help teachers and researchers address problem solving within the classroom.

On the Dynamical Foundations of the Lidov-Kozai Theory

NASA Astrophysics Data System (ADS)

Prokhorenko, V. I.

2018-01-01

The Lidov-Kozai theory developed by each of the authors independently in 1961-1962 is based on qualitative methods of studying the evolution of orbits for the satellite version of the restricted three-body problem (Hill's problem). At present, this theory is in demand in various fields of science: in the field of planetary research within the Solar system, the field of exoplanetary systems, and the field of high-energy physics in interstellar and intergalactic space. This has prompted me to popularize the ideas that underlie the Lidov-Kozai theory based on the experience of using this theory as an efficient tool for solving various problems related to the study of the secular evolution of the orbits of artificial planetary satellites under the influence of external gravitational perturbations with allowance made for the perturbations due to the polar planetary oblateness.

Estimates of the effective compressive strength

NASA Astrophysics Data System (ADS)

Goldstein, R. V.; Osipenko, N. M.

2017-07-01

One problem encountered when determining the effective mechanical properties of large-scale objects, which requires calculating their strength in processes of mechanical interaction with other objects, is related to the possible variability in their local properties including those due to the action of external physical factors. Such problems comprise the determination of the effective strength of bodies one of whose dimensions (thickness) is significantly less than the others and whose properties and/or composition can vary with the thickness. A method for estimating the effective strength of such bodies is proposed and illustrated with example of ice cover strength under longitudinal compression with regard to a partial loss of the ice bearing capacity in deformation. The role of failure localization processes is shown. It is demonstrated that the proposed approach can be used in other problems of fracture mechanics.

Late-time cosmic acceleration: ABCD of dark energy and modified theories of gravity

NASA Astrophysics Data System (ADS)

Sami, M.; Myrzakulov, R.

2016-10-01

We briefly review the problems and prospects of the standard lore of dark energy. We have shown that scalar fields, in principle, cannot address the cosmological constant problem. Indeed, a fundamental scalar field is faced with a similar problem dubbed naturalness. In order to keep the discussion pedagogical, aimed at a wider audience, we have avoided technical complications in several places and resorted to heuristic arguments based on physical perceptions. We presented underlying ideas of modified theories based upon chameleon mechanism and Vainshtein screening. We have given a lucid illustration of recently investigated ghost-free nonlinear massive gravity. Again, we have sacrificed rigor and confined to the basic ideas that led to the formulation of the theory. The review ends with a brief discussion on the difficulties of the theory applied to cosmology.

Hierarchy problem and BSM physics

NASA Astrophysics Data System (ADS)

Bhattacharyya, Gautam

2017-10-01

The `hierarchy problem' plagues the Standard Model of particle physics. The source of this problem is our inability to answer the following question: Why is the Higgs mass so much below the GUT or Planck scale? A brief description about how `supersymmetry' and `composite Higgs' address this problem is given here.

Surveying Graduate Students' Attitudes and Approaches to Problem Solving

ERIC Educational Resources Information Center

Mason, Andrew; Singh, Chandralekha

2010-01-01

Students' attitudes and approaches to problem solving in physics can profoundly influence their motivation to learn and development of expertise. We developed and validated an Attitudes and Approaches to Problem Solving survey by expanding the Attitudes toward Problem Solving survey of Marx and Cummings and administered it to physics graduate…

Phase portraits analysis of a barothropic system: The initial value problem

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

Kuetche, Victor Kamgang, E-mail: vkuetche@yahoo.fr; Department of Physics, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde; The Abdus Salam International Center for Theoretical Physics, Strada Costiera 11, 34014 Trieste

2014-05-15

In this paper, we investigate the phase portraits features of a barothropic relaxing medium under pressure perturbations. In the starting point, we show within a third-order of accuracy that the previous system is modeled by a “dissipative” cubic nonlinear evolution equation. Paying particular attention to high-frequency perturbations of the system, we solve the initial value problem of the system both analytically and numerically while unveiling the existence of localized multivalued waveguide channels. Accordingly, we find that the “dissipative” term with a “dissipative” parameter less than some limit value does not destroy the ambiguous solutions. We address some physical implications ofmore » the results obtained previously.« less

First-Order Frameworks for Managing Models in Engineering Optimization

NASA Technical Reports Server (NTRS)

Alexandrov, Natlia M.; Lewis, Robert Michael

2000-01-01

Approximation/model management optimization (AMMO) is a rigorous methodology for attaining solutions of high-fidelity optimization problems with minimal expense in high- fidelity function and derivative evaluation. First-order AMMO frameworks allow for a wide variety of models and underlying optimization algorithms. Recent demonstrations with aerodynamic optimization achieved three-fold savings in terms of high- fidelity function and derivative evaluation in the case of variable-resolution models and five-fold savings in the case of variable-fidelity physics models. The savings are problem dependent but certain trends are beginning to emerge. We give an overview of the first-order frameworks, current computational results, and an idea of the scope of the first-order framework applicability.

High frequency vibration analysis by the complex envelope vectorization.

PubMed

Giannini, O; Carcaterra, A; Sestieri, A

2007-06-01

The complex envelope displacement analysis (CEDA) is a procedure to solve high frequency vibration and vibro-acoustic problems, providing the envelope of the physical solution. CEDA is based on a variable transformation mapping the high frequency oscillations into signals of low frequency content and has been successfully applied to one-dimensional systems. However, the extension to plates and vibro-acoustic fields met serious difficulties so that a general revision of the theory was carried out, leading finally to a new method, the complex envelope vectorization (CEV). In this paper the CEV method is described, underlying merits and limits of the procedure, and a set of applications to vibration and vibro-acoustic problems of increasing complexity are presented.

Surveying Turkish high school and university students' attitudes and approaches to physics problem solving

NASA Astrophysics Data System (ADS)

Balta, Nuri; Mason, Andrew J.; Singh, Chandralekha

2016-06-01

Students' attitudes and approaches to physics problem solving can impact how well they learn physics and how successful they are in solving physics problems. Prior research in the U.S. using a validated Attitude and Approaches to Problem Solving (AAPS) survey suggests that there are major differences between students in introductory physics and astronomy courses and physics experts in terms of their attitudes and approaches to physics problem solving. Here we discuss the validation, administration, and analysis of data for the Turkish version of the AAPS survey for high school and university students in Turkey. After the validation and administration of the Turkish version of the survey, the analysis of the data was conducted by grouping the data by grade level, school type, and gender. While there are no statistically significant differences between the averages of various groups on the survey, overall, the university students in Turkey were more expertlike than vocational high school students. On an item by item basis, there are statistically differences between the averages of the groups on many items. For example, on average, the university students demonstrated less expertlike attitudes about the role of equations and formulas in problem solving, in solving difficult problems, and in knowing when the solution is not correct, whereas they displayed more expertlike attitudes and approaches on items related to metacognition in physics problem solving. A principal component analysis on the data yields item clusters into which the student responses on various survey items can be grouped. A comparison of the responses of the Turkish and American university students enrolled in algebra-based introductory physics courses shows that on more than half of the items, the responses of these two groups were statistically significantly different, with the U.S. students on average responding to the items in a more expertlike manner.

Experimental and theoretical modelling of sand-water-object interaction under nonlinear progressive waves

NASA Astrophysics Data System (ADS)

Testik, Firat Yener

An experimental and theoretical study has been conducted to obtain a fundamental understanding of the dynamics of the sand, water and a solid object interaction as progressive gravity waves impinge on a sloping beach. Aside from obvious scientific interest, this exceedingly complex physical problem is important for naval applications, related to the behavior of disk/cylindrical shaped objects (mines) in the coastal waters. To address this problem, it was divided into a set of simpler basic problems. To begin, nonlinear progressive waves were investigated experimentally in a wave tank for the case of a rigid (impermeable) sloping bottom. Parameterizations for wave characteristics were proposed and compared with the experiments. In parallel, a numerical wave tank model (NWT) was calibrated using experimental data from a single run, and wave field in the wave tank was simulated numerically for the selected experiments. Subsequently, a layer of sand was placed on the slope and bottom topography evolution processes (ripple and sandbar dynamics, bottom topography relaxation under variable wave forcing, etc.) were investigated experimentally. Models for those processes were developed and verified by experimental measurements. Flow over a circular cylinder placed horizontally on a plane wall was also studied. The far-flow field of the cylinder placed in the wave tank was investigated experimentally and numerical results from the NWT simulations were compared with the experimental data. In the mean time, the near-flow velocity/vorticity field around a short cylinder under steady and oscillatory flow was studied in a towing tank. Horseshoe vortex formation and periodic shedding were documented and explained. With the understanding gained through the aforementioned studies, dynamics and burial/scour around the bottom objects in the wave tank were studied. Possible scenarios on the behavior of the disk-shaped objects were identified and explained. Scour around 3D cylindrical objects was investigated. Different scour regimes were identified experimentally and explained theoretically. Proper physical parameterizations on the time evolution and equilibrium scour characteristics were proposed and verified experimentally.

A Novel Numerical Method for Fuzzy Boundary Value Problems

NASA Astrophysics Data System (ADS)

Can, E.; Bayrak, M. A.; Hicdurmaz

2016-05-01

In the present paper, a new numerical method is proposed for solving fuzzy differential equations which are utilized for the modeling problems in science and engineering. Fuzzy approach is selected due to its important applications on processing uncertainty or subjective information for mathematical models of physical problems. A second-order fuzzy linear boundary value problem is considered in particular due to its important applications in physics. Moreover, numerical experiments are presented to show the effectiveness of the proposed numerical method on specific physical problems such as heat conduction in an infinite plate and a fin.

Physically Abused Women’s Experiences of Sexual Victimization and their Children’s Disruptive Behavior Problems

PubMed Central

Spiller, Laura C.; Jouriles, Ernest N.; McDonald, Renee; Skopp, Nancy A.

2012-01-01

Objective Despite the substantial co-occurrence of women’s experiences of physical and sexual violence, very little is known about their separate and combined effects on child functioning. The present study examines whether sexual victimization experienced by physically abused women is associated with their children’s disruptive behavior problems, after controlling for mothers’ physical victimization and parent to child aggression. It also tests the hypothesis that maternal distress mediates the association between women’s sexual victimization and their children’s disruptive behavior problems. Method The sample includes 449 mothers and their children (4–8 years) who were recruited while residing in domestic violence shelters. Mothers reported on their experiences of physical and sexual victimization over the past year and their current symptoms of psychological distress. Trained diagnosticians interviewed mothers about their children’s disruptive behavior problems. Results Approximately 75% of the women reported experiences of sexual victimization. Physically abused women’s experiences of sexual victimization correlated positively with their children’s disruptive behavior problems and their own psychological distress. The results of path analyses indicated that maternal psychological distress mediates the relation between women’s experiences of sexual victimization and their children’s disruptive behavior problems. Conclusions This research suggests that physically abused women’s experiences of sexual victimization are important for understanding their children’s disruptive behavior problems. Additionally, this research provides further evidence that maternal psychological distress is important for understanding how intimate partner violence might influence children. PMID:23166861

Playful Physics

NASA Technical Reports Server (NTRS)

Weaver, David

2008-01-01

Effectively communicate qualitative and quantitative information orally and in writing. Explain the application of fundamental physical principles to various physical phenomena. Apply appropriate problem-solving techniques to practical and meaningful problems using graphical, mathematical, and written modeling tools. Work effectively in collaborative groups.

Comparing mental health literacy and physical health literacy: an exploratory study.

PubMed

Wickstead, Robert; Furnham, Adrian

2017-10-01

This study compared mental health and physical health literacy using five health problems from each area. The aim was to determine whether the same group had better physical than mental health literacy Method: A sample of 263 participants completed an online questionnaire requiring them to name a problem/illness described in 10 vignettes and suggest treatment options. Five vignettes described mental health problems (anxiety, bipolar-disorder, depression, OCPD and schizophrenia) and five physical problems (angina, COPD, diabetes, a heart attack, and sinusitis). Participants were also asked to rate their sympathy and estimates of prevalence for each disorder. Recognition of the mental health disorders was superior compared recognition of the physical disorders. Analysis of treatment beliefs, sympathy and prevalence ratings also showed significant differences between disorders. Results highlight the importance of education and the lack of public knowledge regarding major physical health conditions.

The Role of Content Knowledge in Ill-Structured Problem Solving for High School Physics Students

ERIC Educational Resources Information Center

Milbourne, Jeff; Wiebe, Eric

2018-01-01

While Physics Education Research has a rich tradition of problem-solving scholarship, most of the work has focused on more traditional, well-defined problems. Less work has been done with ill-structured problems, problems that are better aligned with the engineering and design-based scenarios promoted by the Next Generation Science Standards. This…

The Problem-Solving Process in Physics as Observed When Engineering Students at University Level Work in Groups

ERIC Educational Resources Information Center

Gustafsson, Peter; Jonsson, Gunnar; Enghag, Margareta

2015-01-01

The problem-solving process is investigated for five groups of students when solving context-rich problems in an introductory physics course included in an engineering programme. Through transcripts of their conversation, the paths in the problem-solving process have been traced and related to a general problem-solving model. All groups exhibit…

Statistical physics of hard combinatorial optimization: Vertex cover problem

NASA Astrophysics Data System (ADS)

Zhao, Jin-Hua; Zhou, Hai-Jun

2014-07-01

Typical-case computation complexity is a research topic at the boundary of computer science, applied mathematics, and statistical physics. In the last twenty years, the replica-symmetry-breaking mean field theory of spin glasses and the associated message-passing algorithms have greatly deepened our understanding of typical-case computation complexity. In this paper, we use the vertex cover problem, a basic nondeterministic-polynomial (NP)-complete combinatorial optimization problem of wide application, as an example to introduce the statistical physical methods and algorithms. We do not go into the technical details but emphasize mainly the intuitive physical meanings of the message-passing equations. A nonfamiliar reader shall be able to understand to a large extent the physics behind the mean field approaches and to adjust the mean field methods in solving other optimization problems.

Problems experienced by patients receiving parenteral nutrition at home: results of an open interview study.

PubMed

Huisman-de Waal, Getty; Naber, Ton; Schoonhoven, Lisette; Persoon, Anke; Sauerwein, Hans; van Achterberg, Theo

2006-01-01

Home parenteral nutrition (HPN) is offered to patients who are unable to absorb sufficient nourishment from normal oral food intake or tube feeding. Major causes include severe motility disorders and limited resorption surface in the small intestine. HPN is a lifesaving therapy but has severe consequences on daily life. The aim of this study was to make an inventory of the problems experienced by patients receiving HPN. Open interviews were held with 48 patients from the 2 major centers for HPN in the Netherlands, centered around the question: Which 3 HPN problems have the most severe impact on your daily life? Data were analyzed using content analysis. The respondents mentioned 7 central problems: negative emotions, physical problems, social limitations, dependence on others, incapability, complications, and patient-care provider problems. In addition, practical problems were mentioned: sleeping problems, financial problems, and the "hospital atmosphere" at home. The latter issues formed less of a problem for the patients. The main underlying elements in the lives of many HPN patients appeared to be loss, longing, and grief. In contrast, a smaller proportion of the patients expressed that they had clearly adapted to life with HPN. By means of the HPN, they were still alive and enjoying all the things they could still do.

Numerical simulation of gas distribution in goaf under Y ventilation mode

NASA Astrophysics Data System (ADS)

Li, Shengzhou; Liu, Jun

2018-04-01

Taking the Y type ventilation of the working face as the research object, diffusion equation is introduced to simulate the diffusion characteristics of gas, using Navier-Stokes equation and Brinkman equation to simulate the gas flow in working face and goaf, the physical model of gas flow in coal mining face was established. With numerical simulation software COMSOL multiphysics methods, gas distribution in goaf under Y ventilation mode is simulated and gas distribution of the working face, the upper corner and goaf is analysised. The results show that the Y type ventilation system can effectively improve the corner gas accumulation and overrun problem.

Role of Beliefs and Emotions in Numerical Problem Solving in University Physics Education

ERIC Educational Resources Information Center

Bodin, Madelen; Winberg, Mikael

2012-01-01

Numerical problem solving in classical mechanics in university physics education offers a learning situation where students have many possibilities of control and creativity. In this study, expertlike beliefs about physics and learning physics together with prior knowledge were the most important predictors of the quality of performance of a task…

Mental Health Consumer Experiences and Strategies When Seeking Physical Health Care

PubMed Central

Ewart, Stephanie B.; Bocking, Julia; Happell, Brenda; Platania-Phung, Chris; Stanton, Robert

2016-01-01

People with mental illness have higher rates of physical health problems and consequently live significantly shorter lives. This issue is not yet viewed as a national health priority and research about mental health consumer views on accessing physical health care is lacking. The aim of this study is to explore the experience of mental health consumers in utilizing health services for physical health needs. Qualitative exploratory design was utilized. Semistructured focus groups were held with 31 consumer participants. Thematic analysis revealed that three main themes emerged: scarcity of physical health care, with problems accessing diagnosis, advice or treatment for physical health problems; disempowerment due to scarcity of physical health care; and tenuous empowerment describing survival resistance strategies utilized. Mental health consumers were concerned about physical health and the nonresponsive health system. A specialist physical health nurse consultant within mental health services should potentially redress this gap in health care provision. PMID:28462330

Internet Computer Coaches for Introductory Physics Problem Solving

ERIC Educational Resources Information Center

Xu Ryan, Qing

2013-01-01

The ability to solve problems in a variety of contexts is becoming increasingly important in our rapidly changing technological society. Problem-solving is a complex process that is important for everyday life and crucial for learning physics. Although there is a great deal of effort to improve student problem solving skills throughout the…

Behavior Problems in School-Aged Physically Abused and Neglected Children in Spain.

ERIC Educational Resources Information Center

de Paul, Joaquin; Arruabarrena, M. Ignacia

1995-01-01

This study investigated behavior problems in 66 school-aged physically abused, neglected, and control group children in the Basque Country, Spain. Abused and neglected children had higher subscale scores for social problems, delinquent behavior, and attention problems and showed lower school adjustment. Neglected children appeared more aggressive,…

The effects of recurrent physical abuse on the co-development of behavior problems and posttraumatic stress symptoms among child welfare-involved youth.

PubMed

Yoon, Susan; Barnhart, Sheila; Cage, Jamie

2018-04-27

The primary aim of the current study was to examine the longitudinal effects of ongoing physical abuse on the co-development of externalizing behavior problems and posttraumatic stress (PTS) symptoms among child welfare-involved adolescents. Using three waves of data from the National Survey of Child and Adolescent Well-Being, we performed unconditional and conditional parallel process latent growth curve modeling in a structural equation modeling framework. The study sample included 491 adolescents who were between 11 and 13 years of age at baseline. Higher levels of initial PTS symptoms were associated with higher levels of externalizing behavior problems, but the rate of change in PTS symptoms were not significantly associated with the rate of change in externalizing behavior problems over time. Although physical abuse was concurrently associated with both externalizing behavior problems and PTS symptoms at all assessment points, there were no lagged effects. Additionally, we found that physical abuse indirectly affects subsequent development of externalizing behavior problems and PTS symptoms through ongoing physical abuse. Findings highlight the comorbidity of externalizing behaviors and PTS symptoms among early adolescents in the child welfare system, underlining the importance of screening for and addressing these problems simultaneously. Findings also point to the need for continued assessment of and protection from ongoing physical abuse during adolescence. Copyright © 2018 Elsevier Ltd. All rights reserved.

Design and multi-physics optimization of rotary MRF brakes

NASA Astrophysics Data System (ADS)

Topcu, Okan; Taşcıoğlu, Yiğit; Konukseven, Erhan İlhan

2018-03-01

Particle swarm optimization (PSO) is a popular method to solve the optimization problems. However, calculations for each particle will be excessive when the number of particles and complexity of the problem increases. As a result, the execution speed will be too slow to achieve the optimized solution. Thus, this paper proposes an automated design and optimization method for rotary MRF brakes and similar multi-physics problems. A modified PSO algorithm is developed for solving multi-physics engineering optimization problems. The difference between the proposed method and the conventional PSO is to split up the original single population into several subpopulations according to the division of labor. The distribution of tasks and the transfer of information to the next party have been inspired by behaviors of a hunting party. Simulation results show that the proposed modified PSO algorithm can overcome the problem of heavy computational burden of multi-physics problems while improving the accuracy. Wire type, MR fluid type, magnetic core material, and ideal current inputs have been determined by the optimization process. To the best of the authors' knowledge, this multi-physics approach is novel for optimizing rotary MRF brakes and the developed PSO algorithm is capable of solving other multi-physics engineering optimization problems. The proposed method has showed both better performance compared to the conventional PSO and also has provided small, lightweight, high impedance rotary MRF brake designs.

A cognitive framework for analyzing and describing introductory students' use and understanding of mathematics in physics

NASA Astrophysics Data System (ADS)

Tuminaro, Jonathan

Many introductory, algebra-based physics students perform poorly on mathematical problem solving tasks in physics. There are at least two possible, distinct reasons for this poor performance: (1) students simply lack the mathematical skills needed to solve problems in physics, or (2) students do not know how to apply the mathematical skills they have to particular problem situations in physics. While many students do lack the requisite mathematical skills, a major finding from this work is that the majority of students possess the requisite mathematical skills, yet fail to use or interpret them in the context of physics. In this thesis I propose a theoretical framework to analyze and describe students' mathematical thinking in physics. In particular, I attempt to answer two questions. What are the cognitive tools involved in formal mathematical thinking in physics? And, why do students make the kinds of mistakes they do when using mathematics in physics? According to the proposed theoretical framework there are three major theoretical constructs: mathematical resources, which are the knowledge elements that are activated in mathematical thinking and problem solving; epistemic games, which are patterns of activities that use particular kinds of knowledge to create new knowledge or solve a problem; and frames, which are structures of expectations that determine how individuals interpret situations or events. The empirical basis for this study comes from videotaped sessions of college students solving homework problems. The students are enrolled in an algebra-based introductory physics course. The videotapes were transcribed and analyzed using the aforementioned theoretical framework. Two important results from this work are: (1) the construction of a theoretical framework that offers researchers a vocabulary (ontological classification of cognitive structures) and grammar (relationship between the cognitive structures) for understanding the nature and origin of mathematical use in the context physics, and (2) a detailed understanding, in terms of the proposed theoretical framework, of the errors that students make when using mathematics in the context of physics.

Large-scale studies on the transferability of general problem-solving skills and the pedagogic potential of physics

NASA Astrophysics Data System (ADS)

Mashood, K. K.; Singh, Vijay A.

2013-09-01

Research suggests that problem-solving skills are transferable across domains. This claim, however, needs further empirical substantiation. We suggest correlation studies as a methodology for making preliminary inferences about transfer. The correlation of the physics performance of students with their performance in chemistry and mathematics in highly competitive problem-solving examinations was studied using a massive database. The sample sizes ranged from hundreds to a few hundred thousand. Encouraged by the presence of significant correlations, we interviewed 20 students to explore the pedagogic potential of physics in imparting transferable problem-solving skills. We report strategies and practices relevant to physics employed by these students which foster transfer.

Health problems in adolescents with alcohol use disorders: self-report, liver injury, and physical examination findings and correlates.

PubMed

Clark, D B; Lynch, K G; Donovan, J E; Block, G D

2001-09-01

Although adolescent alcohol consumption has been found to be positively correlated with self-reported health problems, few studies have examined other health indicators. This study compared adolescents with alcohol use disorders (AUDs) and a community reference group on self-reported health problems, serum liver enzymes, and physical examination findings. The relevance of negative emotionality to understanding these health problems was also investigated. The subjects were adolescents with AUDs recruited from clinical programs and classified as having DSM-IV alcohol dependence (n = 71) or alcohol abuse (n = 57) and reference adolescents without AUDs recruited from community sources (n = 131). The assessment of health status included self-reported health problems in 15 areas; serum liver enzyme assays, including gamma-glutamyl transpeptidase, alanine aminotransferase, and aspartate aminotransferase; and physical examination findings. Negative emotionality was determined by systematically combining scores from the Hamilton Anxiety Rating Scale, the Beck Depression Inventory, the Child Behavior Checklist, and the Multidimensional Personality Questionnaire. Adolescent AUDs were associated with more self-reported health problems, higher gamma-glutamyl transpeptidase and alanine aminotransferase levels, and more physical examination abnormalities. Negative emotionality was highly correlated with self-reported health problems, mediated the relationship between AUDs and self-reported health problems, and was not correlated with serum liver enzyme levels or physical examination abnormalities. These results indicated that AUDs during adolescence were associated with health problems, including modest but demonstrable liver injury. Self-reported health problems were probably best understood, in this context, as a negative emotionality manifestation.

Parameter identification for nonlinear aerodynamic systems

NASA Technical Reports Server (NTRS)

Pearson, Allan E.

1991-01-01

Work continues on frequency analysis for transfer function identification, both with respect to the continued development of the underlying algorithms and in the identification study of two physical systems. Some new results of a theoretical nature were recently obtained that lend further insight into the frequency domain interpretation of the research. Progress in each of those areas is summarized. Although not related to the system identification problem, some new results were obtained on the feedback stabilization of linear time lag systems.

A Novel Multiscale QM-MD-SPH Computational Method for Heterogeneous Multicomponent Reactive Systems

DTIC Science & Technology

2017-11-30

The first-principle study on the equation of state of hmx under high pressure. Science China Physics, Mechanics and Astronomy , 54(5):831–835, 2011...J J Monaghan, J C Lattanzio. A refined particle method for astrophysical problems. Astronomy and astrophysics 149 (1985): 135-143. 133 [148] J J...Monaghan. Smoothed particle hydrodynamics. Annual review of astronomy and astrophysics 30.1 (1992): 543-574. [149] J P Morris. A study of the

Stretching a Curved Surface in a Viscous Fluid

NASA Astrophysics Data System (ADS)

Sajid, M.; N., Ali; T., Javed; Z., Abbas

2010-02-01

This work is concerned with the viscous flow due to a curved stretching sheet. The similarity solution of the problem is obtained numerically by a shooting method using the Runge-Kutta algorithm. The physical quantities of interest like the fluid velocity and skin friction coefficient are obtained and discussed under the influence of dimensionless curvature. It is evident from the results that dimensionless curvature causes an increase in boundary layer thickness and a decrease in the skin friction coefficient.

Maestro and Castro: Simulation Codes for Astrophysical Flows

NASA Astrophysics Data System (ADS)

Zingale, Michael; Almgren, Ann; Beckner, Vince; Bell, John; Friesen, Brian; Jacobs, Adam; Katz, Maximilian P.; Malone, Christopher; Nonaka, Andrew; Zhang, Weiqun

2017-01-01

Stellar explosions are multiphysics problems—modeling them requires the coordinated input of gravity solvers, reaction networks, radiation transport, and hydrodynamics together with microphysics recipes to describe the physics of matter under extreme conditions. Furthermore, these models involve following a wide range of spatial and temporal scales, which puts tough demands on simulation codes. We developed the codes Maestro and Castro to meet the computational challenges of these problems. Maestro uses a low Mach number formulation of the hydrodynamics to efficiently model convection. Castro solves the fully compressible radiation hydrodynamics equations to capture the explosive phases of stellar phenomena. Both codes are built upon the BoxLib adaptive mesh refinement library, which prepares them for next-generation exascale computers. Common microphysics shared between the codes allows us to transfer a problem from the low Mach number regime in Maestro to the explosive regime in Castro. Importantly, both codes are freely available (https://github.com/BoxLib-Codes). We will describe the design of the codes and some of their science applications, as well as future development directions.Support for development was provided by NSF award AST-1211563 and DOE/Office of Nuclear Physics grant DE-FG02-87ER40317 to Stony Brook and by the Applied Mathematics Program of the DOE Office of Advance Scientific Computing Research under US DOE contract DE-AC02-05CH11231 to LBNL.

Factors associated with different smoking status in European adolescents: results of the SEYLE study.

PubMed

Banzer, Raphaela; Haring, C; Buchheim, A; Oehler, S; Carli, V; Wasserman, C; Kaess, M; Apter, A; Balazs, J; Bobes, J; Brunner, R; Corcoran, P; Cosman, D; Hoven, C W; Kahn, J P; Keeley, H S; Postuvan, V; Podlogar, T; Sisask, M; Värnik, A; Sarchiapone, M; Wasserman, D

2017-11-01

Early onset and long-term smoking are associated with physical and psychological health problems. The aim of the presented analysis was to investigate risk and influencing factors for different smoking status in a big sample of European adolescents. In the context of the "saving and empowering young lives in Europe" (SEYLE) study we surveyed 12,328 adolescents at the age of 13-17 from 11 countries. The survey took place in a school-based context using a questionnaire. Overall 58% reported the onset of ever-smoking under the age of 14 and 30.9% smoke on a daily basis. Multinomial logistic regression model showed significant positive associations between adolescent smoking and internalizing problems (suicidal behavior, direct self-injurious behavior, anxiety), externalizing problems (conduct problems, hyperactivity, substance consumption) and family problems (parental substance consumption, broken home). Our data show that smoking among adolescents is still a major public health problem and adolescents who smoke are at higher risk for mental problems. Further, adolescent smoking is associated with broken home families and parental behaviors. Therefore, early preventive measures are necessary not only for adolescents, but also for their parents.

Morphological computation and morphological control: steps toward a formal theory and applications.

PubMed

Füchslin, Rudolf M; Dzyakanchuk, Andrej; Flumini, Dandolo; Hauser, Helmut; Hunt, Kenneth J; Luchsinger, Rolf H; Reller, Benedikt; Scheidegger, Stephan; Walker, Richard

2013-01-01

Morphological computation can be loosely defined as the exploitation of the shape, material properties, and physical dynamics of a physical system to improve the efficiency of a computation. Morphological control is the application of morphological computing to a control task. In its theoretical part, this article sharpens and extends these definitions by suggesting new formalized definitions and identifying areas in which the definitions we propose are still inadequate. We go on to describe three ongoing studies, in which we are applying morphological control to problems in medicine and in chemistry. The first involves an inflatable support system for patients with impaired movement, and is based on macroscopic physics and concepts already tested in robotics. The two other case studies (self-assembly of chemical microreactors; models of induced cell repair in radio-oncology) describe processes and devices on the micrometer scale, in which the emergent dynamics of the underlying physical system (e.g., phase transitions) are dominated by stochastic processes such as diffusion.

Information fusion methods based on physical laws.

PubMed

Rao, Nageswara S V; Reister, David B; Barhen, Jacob

2005-01-01

We consider systems whose parameters satisfy certain easily computable physical laws. Each parameter is directly measured by a number of sensors, or estimated using measurements, or both. The measurement process may introduce both systematic and random errors which may then propagate into the estimates. Furthermore, the actual parameter values are not known since every parameter is measured or estimated, which makes the existing sample-based fusion methods inapplicable. We propose a fusion method for combining the measurements and estimators based on the least violation of physical laws that relate the parameters. Under fairly general smoothness and nonsmoothness conditions on the physical laws, we show the asymptotic convergence of our method and also derive distribution-free performance bounds based on finite samples. For suitable choices of the fuser classes, we show that for each parameter the fused estimate is probabilistically at least as good as its best measurement as well as best estimate. We illustrate the effectiveness of this method for a practical problem of fusing well-log data in methane hydrate exploration.

Helping Students with Problems: What Physical Educators Can Do.

ERIC Educational Resources Information Center

Jones, C. J.; Nelson, Barbara

1985-01-01

Children often have trouble finding effective ways to deal with daily stress. Physical educators work in an environment where they can observe and study their students. Suggestions are offered for physical education teachers dealing with students with problems. (DF)

Research in Theoretical High Energy Physics- Final Report

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

Okada, Nobuchika

PI Dr. Okada’s research interests are centered on phenomenological aspects of particle physics. It has been abundantly clear in recent years that an extension of the Standard Model (SM), i.e. new physics beyond the SM, is needed to explain a number of experimental observations such as the neutrino oscillation data, the existence of non-baryonic dark matter, and the observed baryon asymmetry of the Universe. In addition, the SM suffers from several theoretical/conceptual problems, such as the gauge hierarchy problem, the fermion mass hierarchy problem, and the origin of the electroweak symmetry breaking. It is believed that these problems can alsomore » be solved by new physics beyond the SM. The main purpose of the Dr. Okada’s research is a theoretical investigation of new physics opportunities from various phenomenological points of view, based on the recent progress of experiments/observations in particle physics and cosmology. There are many possibilities to go beyond the SM and many new physics models have been proposed. The major goal of the project is to understand the current status of possible new physics models and obtain the future prospects of new physics phenomena toward their discoveries.« less

Repackaging undergraduate physics programs

NASA Astrophysics Data System (ADS)

Garner, James

1997-03-01

During the nineties the undergraduate physics major has experienced a number of problems that are not especially new. However, the severity of these problems may be at an all time high. The problems concern such matters as the difficulty of recruiting majors, the retention of majors and non-majors in our physics courses, and a poor employment picture for the B.S. physics graduates. The seriousness of these problems has reached such a profound level that it may be time for the physics community to reexamine a disturbing but fundamental question, i.e., what should be the primary purpose of the undergraduate physics program in our universities? Indeed, this question seems to be one of the primary focuses of this physics education conference. In previous eras physics departments did not have to be greatly concerned about these issues. Traditionally, physics was considered one of the liberal arts and we could tell prospective majors that if they wanted to work in a physics-related job then they should enroll in physics graduate studies. We expected most of them, at least the "worthy" ones, to do just that. We often callously disregarded the low retention of students in our courses with flippant phrases like, "we are just weeding them out." There seemed to be plenty of students eager to enter our exciting discipline and industry was quick to snatch up these excellent problem solvers when they finished their degree. Many would agree that this picture changed in the post cold-war nineties and things may never be the way they used to be.

Complex network problems in physics, computer science and biology

NASA Astrophysics Data System (ADS)

Cojocaru, Radu Ionut

There is a close relation between physics and mathematics and the exchange of ideas between these two sciences are well established. However until few years ago there was no such a close relation between physics and computer science. Even more, only recently biologists started to use methods and tools from statistical physics in order to study the behavior of complex system. In this thesis we concentrate on applying and analyzing several methods borrowed from computer science to biology and also we use methods from statistical physics in solving hard problems from computer science. In recent years physicists have been interested in studying the behavior of complex networks. Physics is an experimental science in which theoretical predictions are compared to experiments. In this definition, the term prediction plays a very important role: although the system is complex, it is still possible to get predictions for its behavior, but these predictions are of a probabilistic nature. Spin glasses, lattice gases or the Potts model are a few examples of complex systems in physics. Spin glasses and many frustrated antiferromagnets map exactly to computer science problems in the NP-hard class defined in Chapter 1. In Chapter 1 we discuss a common result from artificial intelligence (AI) which shows that there are some problems which are NP-complete, with the implication that these problems are difficult to solve. We introduce a few well known hard problems from computer science (Satisfiability, Coloring, Vertex Cover together with Maximum Independent Set and Number Partitioning) and then discuss their mapping to problems from physics. In Chapter 2 we provide a short review of combinatorial optimization algorithms and their applications to ground state problems in disordered systems. We discuss the cavity method initially developed for studying the Sherrington-Kirkpatrick model of spin glasses. We extend this model to the study of a specific case of spin glass on the Bethe lattice at zero temperature and then we apply this formalism to the K-SAT problem defined in Chapter 1. The phase transition which physicists study often corresponds to a change in the computational complexity of the corresponding computer science problem. Chapter 3 presents phase transitions which are specific to the problems discussed in Chapter 1 and also known results for the K-SAT problem. We discuss the replica method and experimental evidences of replica symmetry breaking. The physics approach to hard problems is based on replica methods which are difficult to understand. In Chapter 4 we develop novel methods for studying hard problems using methods similar to the message passing techniques that were discussed in Chapter 2. Although we concentrated on the symmetric case, cavity methods show promise for generalizing our methods to the un-symmetric case. As has been highlighted by John Hopfield, several key features of biological systems are not shared by physical systems. Although living entities follow the laws of physics and chemistry, the fact that organisms adapt and reproduce introduces an essential ingredient that is missing in the physical sciences. In order to extract information from networks many algorithm have been developed. In Chapter 5 we apply polynomial algorithms like minimum spanning tree in order to study and construct gene regulatory networks from experimental data. As future work we propose the use of algorithms like min-cut/max-flow and Dijkstra for understanding key properties of these networks.

Media and technology use predicts ill-being among children, preteens and teenagers independent of the negative health impacts of exercise and eating habits.

PubMed

Rosen, L D; Lim, A F; Felt, J; Carrier, L M; Cheever, N A; Lara-Ruiz, J M; Mendoza, J S; Rokkum, J

2014-06-01

The American Academy of Pediatrics recommends no screen time for children under the age of 2 and limited screen time for all children. However, no such guidelines have been proposed for preteens and teenagers. Further, research shows that children, preteens, and teenagers are using massive amounts of media and those with more screen time have been shown to have increased obesity, reduced physical activity, and decreased health. This study examined the impact of technology on four areas of ill-being-psychological issues, behavior problems, attention problems and physical health-among children (aged 4-8), preteens (9-12), and teenagers (13-18) by having 1030 parents complete an online, anonymous survey about their own and their child's behaviors. Measures included daily technology use, daily food consumption, daily exercise, and health. Hypothesis 1, which posited that unhealthy eating would predict impaired ill-being, was partially supported, particularly for children and preteens. Hypothesis 2, which posited that reduced physical activity would predict diminished health levels, was partially supported for preteens and supported for teenagers. Hypothesis 3, that increased daily technology use would predict ill-being after factoring out eating habits and physical activity, was supported. For children and preteens, total media consumption predicted illbeing while for preteens specific technology uses, including video gaming and electronic communication, predicted ill-being. For teenagers, nearly every type of technological activity predicted poor health. Practical implications were discussed in terms of setting limits and boundaries on technology use and encouraging healthy eating and physical activity at home and at school.

Surveillance of psychosomatic disorders in internal medicine in Cipto Mangunkusumo Hospital, Jakarta, Indonesia.

PubMed

Shatri, Hamzah; Mudjaddid, E; Lapau, Buchari

2004-01-01

to examine certain characteristics of patients who suffer from psychosomatic disorders. We called data through medical report outpatient clinic of the Psychosomatic Division, Department of internal medicine, Cipto Mangunkusumo Central General Hospital/Faculty of Medicine of the University of Indonesia (FKUI/RSUPN-CM), Jakarta, Indonesia, in 1996. The data was processed manually and by computer from which table and graphic were obtained. The descriptive analysis was performed to the objective the study. the FPD patients consisted of those with vegetative imbalance (multiple psychosomatic syndrome) (30.2%), dyspepsia (20.8%), functional heart disease (11.3%) and others 1%-6%. All of SPD consisted of chronic disease, such as hypertension (38.3%), diabetes mellitus (29.8%), bronchial asthma (10.6%), coronary artery disease (6.4%), and others 2%-5%. According to DSM IV, among the psychosomatic patients, 52.7% met the criteria for anxiety, 29.3% for depression, 14.2% for mixed anxiety and depression, and 3.8% unclear. The psychosocial stressor groups were family problems (38%), physical conditions (16%), work-related problems (13.4%), marriage problems (8.4%) and others (1%-4%). The most common physical symptoms of psychosomatic disorders were functional. Common functional psychosomatic disorders were multiple psychosomatic syndrome, dyspepsia and functional heart disease. Structural disorders found were chronic diseases. There was no difference in prevalence between males and females. The most frequent functional disorders were more commonly found among those under 40 years of age, while those with structural disorders were more common among patients 40 years of age or more. The psychological diagnoses were anxiety and depression. The most frequent psychological stressors were family problems, medical conditions, work-related problems and marriage problems.

Reminder Cards Improve Physician Documentation of Obesity But Not Obesity Counseling.

PubMed

Shungu, Nicholas; Miller, Marshal N; Mills, Geoffrey; Patel, Neesha; de la Paz, Amanda; Rose, Victoria; Kropa, Jill; Edi, Rina; Levy, Emily; Crenshaw, Margaret; Hwang, Chris

2015-01-01

Physicians frequently fail to document obesity and obesity-related counseling. We sought to determine whether attaching a physical reminder card to patient encounter forms would increase electronic medical record (EMR) assessment of and documentation of obesity and dietary counseling. Reminder cards for obesity documentation were attached to encounter forms for patient encounters over a 2-week intervention period. For visits in the intervention period, the EMR was retrospectively reviewed for BMI, assessment of "obesity" or "morbid obesity" as an active problem, free-text dietary counseling within physician notes, and assessment of "dietary counseling" as an active problem. These data were compared to those collected through a retrospective chart review during a 2-week pre-intervention period. We also compared physician self-report of documentation via reminder cards with EMR documentation. We found significant improvement in the primary endpoint of assessment of "obesity" or "morbid obesity" as an active problem (42.5% versus 28%) compared to the pre-intervention period. There was no significant difference in the primary endpoints of free-text dietary counseling or assessment of "dietary counseling" as an active problem between the groups. Physician self-reporting of assessment of "obesity" or "morbid obesity" as an active problem (77.7% versus 42.5%), free-text dietary counseling on obesity (69.1% versus 35.4%) and assessment of "dietary counseling" as an active problem (54.3% versus 25.2%) were all significantly higher than those reflected in EMR documentation. This study demonstrates that physical reminder cards are a successful means of increasing obesity documentation rates among providers but do not necessarily increase rates of obesity-related counseling or documentation of counseling. Our study suggests that even with such interventions, physicians are likely under-documenting obesity and counseling compared to self-reported rates.

On some physical and dynamical properties of microplastic particles in marine environment.

PubMed

Chubarenko, I; Bagaev, A; Zobkov, M; Esiukova, E

2016-07-15

Simplified physical models and geometrical considerations reveal general physical and dynamical properties of microplastic particles (0.5-5mm) of different density, shape and size in marine environment. Windage of extremely light foamed particles, surface area and fouling rate of slightly positively buoyant microplastic spheres, films and fibres and settling velocities of negatively buoyant particles are analysed. For the Baltic Sea dimensions and under the considered idealised external conditions, (i) only one day is required for a foamed polystyrene particle to cross the sea (ca. 250km); (ii) polyethylene fibres should spend about 6-8months in the euphotic zone before sinking due to bio-fouling, whilst spherical particles can be retained on the surface up to 10-15years; (iii) for heavy microplastic particles, the time of settling through the water column in the central Gotland basin (ca. 250m) is less than 18h. Proper physical setting of the problem of microplastics transport and developing of physically-based parameterisations are seen as applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physics and Its Interfaces with Medicinal Chemistry and Drug Design

NASA Astrophysics Data System (ADS)

Santos, Ricardo N.; Andricopulo, Adriano D.

2013-08-01

Medicinal chemistry is a multidisciplinary subject that integrates knowledge from a variety of fields of science, including, but not limited to, chemistry, biology, and physics. The area of drug design involves the cooperative work of scientists with a diverse range of backgrounds and technical skills, trying to tackle complex problems using an integration of approaches and methods. One important contribution to this field comes from physics through studies that attempt to identify and quantify the molecular interactions between small molecules (drugs) and biological targets (receptors), such as the forces that govern the interactions, the thermodynamics of the drug-receptor interactions, and so on. In this context, the interfaces of physics, medicinal chemistry, and drug design are of vital importance for the development of drugs that not only have the right chemistry but also the right intermolecular properties to interact at the macromolecular level, providing useful information about the principles and molecular mechanisms underlying the therapeutic action of drugs. This article highlights some of the most important connections between physics and medicinal chemistry in the design of new drugs.

Constructor theory of information

PubMed Central

Deutsch, David; Marletto, Chiara

2015-01-01

We propose a theory of information expressed solely in terms of which transformations of physical systems are possible and which are impossible—i.e. in constructor-theoretic terms. It includes conjectured, exact laws of physics expressing the regularities that allow information to be physically instantiated. Although these laws are directly about information, independently of the details of particular physical instantiations, information is not regarded as an a priori mathematical or logical concept, but as something whose nature and properties are determined by the laws of physics alone. This theory solves a problem at the foundations of existing information theory, namely that information and distinguishability are each defined in terms of the other. It also explains the relationship between classical and quantum information, and reveals the single, constructor-theoretic property underlying the most distinctive phenomena associated with the latter, including the lack of in-principle distinguishability of some states, the impossibility of cloning, the existence of pairs of variables that cannot simultaneously have sharp values, the fact that measurement processes can be both deterministic and unpredictable, the irreducible perturbation caused by measurement, and locally inaccessible information (as in entangled systems). PMID:25663803

Mental health consequences of international migration for Vietnamese Americans and the mediating effects of physical health and social networks: results from a natural experiment approach.

PubMed

Fu, Hongyun; VanLandingham, Mark J

2012-05-01

Although the existing literature on immigrant mental health is extensive, major substantive and methodological gaps remain. Substantively, there is little population-based research that focuses on the mental health consequences of migration for Vietnamese Americans. More generally, although a wide range of mental health problems among immigrants has been identified, the potential causal or mediating mechanisms underlying these problems remain elusive. This latter substantive shortcoming is related to a key methodological challenge involving the potentially confounding effects of selection on migration-related outcomes. This article addresses these challenges by employing a "natural experiment" design, involving comparisons among three population-based samples of Vietnamese immigrants, never-leavers, and returnees (N=709). Data were collected in Ho Chi Minh City and in New Orleans between 2003 and 2005. The study investigates the long-term impact of international migration on Vietnamese mental health, and the potential mediating effects of social networks and physical health on these migration-related outcomes. The results reveal both mental health advantages and disadvantages among Vietnamese immigrants relative to the two groups of Vietnamese nationals. Selection can be ruled out for some of these differences, and both social networks and physical health are found to play important explanatory roles.

On simulated annealing phase transitions in phylogeny reconstruction.

PubMed

Strobl, Maximilian A R; Barker, Daniel

2016-08-01

Phylogeny reconstruction with global criteria is NP-complete or NP-hard, hence in general requires a heuristic search. We investigate the powerful, physically inspired, general-purpose heuristic simulated annealing, applied to phylogeny reconstruction. Simulated annealing mimics the physical process of annealing, where a liquid is gently cooled to form a crystal. During the search, periods of elevated specific heat occur, analogous to physical phase transitions. These simulated annealing phase transitions play a crucial role in the outcome of the search. Nevertheless, they have received comparably little attention, for phylogeny or other optimisation problems. We analyse simulated annealing phase transitions during searches for the optimal phylogenetic tree for 34 real-world multiple alignments. In the same way in which melting temperatures differ between materials, we observe distinct specific heat profiles for each input file. We propose this reflects differences in the search landscape and can serve as a measure for problem difficulty and for suitability of the algorithm's parameters. We discuss application in algorithmic optimisation and as a diagnostic to assess parameterisation before computationally costly, large phylogeny reconstructions are launched. Whilst the focus here lies on phylogeny reconstruction under maximum parsimony, it is plausible that our results are more widely applicable to optimisation procedures in science and industry. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Physical basis of the Thellier-Thellier and related paleointensity methods

NASA Astrophysics Data System (ADS)

Dunlop, David J.

2011-08-01

Émile and Odette Thellier produced the first reliable determinations of paleointensity following an experimental protocol used earlier by Johann Koenigsberger. Although Koenigsberger did groundbreaking work on thermoremanent magnetization (TRM), it was the Thelliers who formulated the fundamental idea of partial TRMs as building blocks for TRM. In his 1938 doctoral thesis and a series of short notes, Émile Thellier minutely examined the data on TRM and partial TRM, ultimately establishing for bricks and other baked clays his laws of pTRM reciprocity, independence and additivity. In 1946 he speculated that blocking represents "…immobilization of elementary magnetic moments below a temperature Θ … Θ will vary at each point in the body, perhaps with the dimensions and the shape of the crystalline grains … One can thus explain thermoremanence by the progressive fixing, in the course of cooling, of moments which find themselves held fast when they pass through their individual temperature Θ." Thellier thus established the physical basis of TRM blocking and recognized the essential role of grain size and shape. In 1949 Louis Néel quantified these concepts in terms of the properties of single-domain grains. Today the Thellier-Thellier method remains the benchmark of reliable paleointensity data. The challenge has been the non-ideality of real geological and archeological materials: TRM carriers larger than single-domain size and physicochemical alteration during heating. The Thelliers avoided these problems by using bricks and pottery previously fired under conditions similar to those in laboratory heatings, eschewing volcanic and other rocks. But despite their problems, we have to deal with the material nature provides. This paper provides insights into the physics underlying the Thellier-Thellier method and check procedures that detect non-ideal behavior, as well as reviewing recent advances in paleointensity methodology.

Dynamic Emulation Modelling (DEMo) of large physically-based environmental models

NASA Astrophysics Data System (ADS)

Galelli, S.; Castelletti, A.

2012-12-01

In environmental modelling large, spatially-distributed, physically-based models are widely adopted to describe the dynamics of physical, social and economic processes. Such an accurate process characterization comes, however, to a price: the computational requirements of these models are considerably high and prevent their use in any problem requiring hundreds or thousands of model runs to be satisfactory solved. Typical examples include optimal planning and management, data assimilation, inverse modelling and sensitivity analysis. An effective approach to overcome this limitation is to perform a top-down reduction of the physically-based model by identifying a simplified, computationally efficient emulator, constructed from and then used in place of the original model in highly resource-demanding tasks. The underlying idea is that not all the process details in the original model are equally important and relevant to the dynamics of the outputs of interest for the type of problem considered. Emulation modelling has been successfully applied in many environmental applications, however most of the literature considers non-dynamic emulators (e.g. metamodels, response surfaces and surrogate models), where the original dynamical model is reduced to a static map between input and the output of interest. In this study we focus on Dynamic Emulation Modelling (DEMo), a methodological approach that preserves the dynamic nature of the original physically-based model, with consequent advantages in a wide variety of problem areas. In particular, we propose a new data-driven DEMo approach that combines the many advantages of data-driven modelling in representing complex, non-linear relationships, but preserves the state-space representation typical of process-based models, which is both particularly effective in some applications (e.g. optimal management and data assimilation) and facilitates the ex-post physical interpretation of the emulator structure, thus enhancing the credibility of the model to stakeholders and decision-makers. Numerical results from the application of the approach to the reduction of 3D coupled hydrodynamic-ecological models in several real world case studies, including Marina Reservoir (Singapore) and Googong Reservoir (Australia), are illustrated.

Are Adolescent Girls with a Physical Disability at Increased Risk for Sexual Violence?

ERIC Educational Resources Information Center

Alriksson-Schmidt, Ann I.; Armour, Brian S.; Thibadeau, Judy K.

2010-01-01

Background: The purpose of this study was to investigate whether US female adolescents who self-reported having a physical disability or long-term health problem were more likely to report having been physically forced to have sexual intercourse than US female adolescents without a physical disability or long-term health problem. Methods: Using…

Problem Solving and the Use of Math in Physics Courses

ERIC Educational Resources Information Center

Redish, Edward F.

2006-01-01

Mathematics is an essential element of physics problem solving, but experts often fail to appreciate exactly how they use it. Math may be the language of science, but math-in-physics is a distinct dialect of that language. Physicists tend to blend conceptual physics with mathematical symbolism in a way that profoundly affects the way equations are…

An efficient computational method for solving nonlinear stochastic Itô integral equations: Application for stochastic problems in physics

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

Heydari, M.H., E-mail: heydari@stu.yazd.ac.ir; The Laboratory of Quantum Information Processing, Yazd University, Yazd; Hooshmandasl, M.R., E-mail: hooshmandasl@yazd.ac.ir

Because of the nonlinearity, closed-form solutions of many important stochastic functional equations are virtually impossible to obtain. Thus, numerical solutions are a viable alternative. In this paper, a new computational method based on the generalized hat basis functions together with their stochastic operational matrix of Itô-integration is proposed for solving nonlinear stochastic Itô integral equations in large intervals. In the proposed method, a new technique for computing nonlinear terms in such problems is presented. The main advantage of the proposed method is that it transforms problems under consideration into nonlinear systems of algebraic equations which can be simply solved. Errormore » analysis of the proposed method is investigated and also the efficiency of this method is shown on some concrete examples. The obtained results reveal that the proposed method is very accurate and efficient. As two useful applications, the proposed method is applied to obtain approximate solutions of the stochastic population growth models and stochastic pendulum problem.« less

Effects of oil development in Arctic America

USGS Publications Warehouse

Reed, J.C.

1970-01-01

Large and important discoveries of petroleum were made in northern Alaska in 1968. The reserves were estimated then to be perhaps as much as ten thousand million barrels. Subsequent exploration has shown the resources to be much greater than was estimated earlier. Many problems must be solved before petroleum from northern Alaska reaches the world's markets. These problems are of three types: 1, those related to exploring, developing, and operating under the physical environments of the region; 2, those having to do with people-both the native people and those brought in from lower latitudes-and 3, those concerning the protection of the natural environments. The problems are great, but so also are the reserves of petroleum. To the extent that the problems are not solved, the cost of development and operation will be higher, the use of people will be expensive and unsatisfactory, and the natural environments will be threatened. The whole effort could be jeopardized on those grounds. ?? 1970.

The application of hybrid artificial intelligence systems for forecasting

NASA Astrophysics Data System (ADS)

Lees, Brian; Corchado, Juan

1999-03-01

The results to date are presented from an ongoing investigation, in which the aim is to combine the strengths of different artificial intelligence methods into a single problem solving system. The premise underlying this research is that a system which embodies several cooperating problem solving methods will be capable of achieving better performance than if only a single method were employed. The work has so far concentrated on the combination of case-based reasoning and artificial neural networks. The relative merits of artificial neural networks and case-based reasoning problem solving paradigms, and their combination are discussed. The integration of these two AI problem solving methods in a hybrid systems architecture, such that the neural network provides support for learning from past experience in the case-based reasoning cycle, is then presented. The approach has been applied to the task of forecasting the variation of physical parameters of the ocean. Results obtained so far from tests carried out in the dynamic oceanic environment are presented.

Physical and psychological morbidities among selected antenatal females in Kegalle district of Sri Lanka: A cross sectional study.

PubMed

Herath, I N S; Balasuriya, A; Sivayogan, S

2017-10-01

While motherhood is often a positive and satisfying experience, for some women, it is linked with suffering and ill-health. A woman should be able to feel physically and mentally content during pregnancy. Discomforts in pregnancy may be considered as insignificant by the physician. Therefore, the objective of this study was to determine physical and psychological morbidities among primigravid antenatal females in the Kegalle District, Sri Lanka. A sample of 1017 second and third trimester primigravid antenatal females selected by a two-stage probability proportional to size cluster sampling method, were assessed for physical and psychological problems. Data analysis was done using SPSS 16 package and associations were found using Chi square test with p values. The presence of any physical health problem during the preceding 14 days was reported by 75.7% (95% CI 73.0-78.2) of females though each individual physical problem was reported by less than or around one-third. Prevalence of psychological distress and depression was 22.7% (95% CI 20.2-25.4) and 10.4% (95% CI 8.7-12.4), respectively. The self-rated health was very good in 24.7% and good in 55.9%. Older employed females had significantly higher physical problems. It is concluded that although the self-rated wellbeing during pregnancy is high, the presence of physical and psychological ill-health is substantial. Impact statement Pregnancy is a time of intense physical change and is associated with emotional upheaval in many women. Obstetric morbidity is defined as morbidity in a woman who has been pregnant regardless of the site or the duration of the pregnancy, from any cause related to or aggravated by the pregnancy or its management, but not from accidental or incidental causes. It is classified into three categories namely; direct, indirect and psychological obstetric morbidity. For one maternal death, there can be between 9 and 16 females with obstetric morbidity depending on the level of development of a country. As a country with good health indicators, this study was conducted to determine physical and psychological problems among primigravid antenatal females in the Kegalle District,p Sri Lanka to improve service quality further. The presence of any physical health problem during the preceding 14 days was reported by a quarter of females and backache, fatigue, body aches, psychological distress, urinary incontinence and headache was commonly reported individual problems. Older employed females had significantly higher physical problems. Though trivial for health workers, physical and psychological problems are prevalent. These should be actively sought and remedied by health workers to improve the quality of life.

A predictive parameter estimation approach for the thermodynamically constrained averaging theory applied to diffusion in porous media

NASA Astrophysics Data System (ADS)

Valdes-Parada, F. J.; Ostvar, S.; Wood, B. D.; Miller, C. T.

2017-12-01

Modeling of hierarchical systems such as porous media can be performed by different approaches that bridge microscale physics to the macroscale. Among the several alternatives available in the literature, the thermodynamically constrained averaging theory (TCAT) has emerged as a robust modeling approach that provides macroscale models that are consistent across scales. For specific closure relation forms, TCAT models are expressed in terms of parameters that depend upon the physical system under study. These parameters are usually obtained from inverse modeling based upon either experimental data or direct numerical simulation at the pore scale. Other upscaling approaches, such as the method of volume averaging, involve an a priori scheme for parameter estimation for certain microscale and transport conditions. In this work, we show how such a predictive scheme can be implemented in TCAT by studying the simple problem of single-phase passive diffusion in rigid and homogeneous porous media. The components of the effective diffusivity tensor are predicted for several porous media by solving ancillary boundary-value problems in periodic unit cells. The results are validated through a comparison with data from direct numerical simulation. This extension of TCAT constitutes a useful advance for certain classes of problems amenable to this estimation approach.

Accuracy of self-reported medical problems in patients with alcohol dependence and co-occurring schizophrenia or schizoaffective disorder.

PubMed

Meszaros, Zsuzsa Szombathyne; Dimmock, Jacqueline A; Ploutz-Snyder, Robert; Chauhan, Sumerendra Vir Singh; Abdul-Malak, Ynesse; Middleton, Frank A; Batki, Steven L

2011-11-01

Schizophrenia and alcohol dependence (AD) are both major risk factors for a variety of medical problems, yet little is known about the medical status of patients in whom both conditions coexist. The objectives of this study are to assess accuracy of self-reported medical problems and to compare the accuracy reports in patients with schizophrenia or schizoaffective disorder and co-occurring AD compared to patients with AD only and to controls. Our hypothesis was that medical problems are under-reported in patients with co-occurring disorders, possibly due to the combination of alcohol use and symptoms of schizophrenia. Self-reported medical diagnoses were recorded and compared to medical records obtained from all area hospitals in 42 patients with schizophrenia and AD, 44 patients with schizoaffective disorder and AD, 41 patients with AD only, and 15 control subjects. Patients underwent medical history, physical examination, and review of medical records. Patients with schizophrenia or schizoaffective disorder and co-occurring AD underreported their medical problems significantly more than patients with AD only and controls. Accuracy of self report was significantly lower in patients with schizophrenia-spectrum disorders plus co-occurring alcohol dependence than in AD alone or in controls. The most commonly underreported diagnoses included coronary artery disease, chronic renal failure, seizure disorder, hyperlipidemia, asthma and hypertension. In order to detect potentially unreported medical conditions in patients with co-occurring schizophrenia/schizoaffective disorder and alcohol dependence, the use of targeted screening questionnaires is recommended in addition to physical examination and thorough review of medical records. Copyright © 2011 Elsevier B.V. All rights reserved.

Stochastic Processes in Physics: Deterministic Origins and Control

NASA Astrophysics Data System (ADS)

Demers, Jeffery

Stochastic processes are ubiquitous in the physical sciences and engineering. While often used to model imperfections and experimental uncertainties in the macroscopic world, stochastic processes can attain deeper physical significance when used to model the seemingly random and chaotic nature of the underlying microscopic world. Nowhere more prevalent is this notion than in the field of stochastic thermodynamics - a modern systematic framework used describe mesoscale systems in strongly fluctuating thermal environments which has revolutionized our understanding of, for example, molecular motors, DNA replication, far-from equilibrium systems, and the laws of macroscopic thermodynamics as they apply to the mesoscopic world. With progress, however, come further challenges and deeper questions, most notably in the thermodynamics of information processing and feedback control. Here it is becoming increasingly apparent that, due to divergences and subtleties of interpretation, the deterministic foundations of the stochastic processes themselves must be explored and understood. This thesis presents a survey of stochastic processes in physical systems, the deterministic origins of their emergence, and the subtleties associated with controlling them. First, we study time-dependent billiards in the quivering limit - a limit where a billiard system is indistinguishable from a stochastic system, and where the simplified stochastic system allows us to view issues associated with deterministic time-dependent billiards in a new light and address some long-standing problems. Then, we embark on an exploration of the deterministic microscopic Hamiltonian foundations of non-equilibrium thermodynamics, and we find that important results from mesoscopic stochastic thermodynamics have simple microscopic origins which would not be apparent without the benefit of both the micro and meso perspectives. Finally, we study the problem of stabilizing a stochastic Brownian particle with feedback control, and we find that in order to avoid paradoxes involving the first law of thermodynamics, we need a model for the fine details of the thermal driving noise. The underlying theme of this thesis is the argument that the deterministic microscopic perspective and stochastic mesoscopic perspective are both important and useful, and when used together, we can more deeply and satisfyingly understand the physics occurring over either scale.

UK-based physical therapists' attitudes and beliefs regarding exercise and knee osteoarthritis: findings from a mixed-methods study.

PubMed

Holden, Melanie A; Nicholls, Elaine E; Young, Julie; Hay, Elaine M; Foster, Nadine E

2009-11-15

Within the UK, differences exist between physical therapists' use of exercise for patients with knee osteoarthritis (OA) and recent exercise recommendations. This may be explained by their underlying attitudes and beliefs. We aimed to describe UK physical therapists' attitudes and beliefs regarding exercise and knee OA, and understand and explain them. A survey was mailed to 2,000 UK-based chartered physical therapists that included 23 attitude statements derived from recently published recommendations. Semistructured telephone interviews were conducted with a purposeful sample of questionnaire respondents (n = 24), and were recorded and analyzed thematically. The questionnaire response rate was 58% (n = 1,152); 538 respondents reported treating a patient with knee OA in the last 6 months. The survey highlighted uncertainty about potential benefits of exercise for knee OA: only 56% largely/totally agreed that knee problems are improved by local exercise. Although exercise adherence was deemed important, it was seen as the patient's, not the therapist's, responsibility. Interviews revealed an underlying biomedical model of care of knee pain, with knee OA viewed as a progressive degenerative condition. A paternalistic treatment approach was evident. Health care systems presented a number of barriers to best practice, including limited opportunity to provide followup. Although the attitudes and beliefs of physical therapists may help to explain differences between current practice and recent exercise recommendations, the wider health care system also plays a part. Further research is needed to support meaningful shifts in physical therapy care in line with the best practice recommendations.

The Physics Workbook: A Needed Instructional Device.

ERIC Educational Resources Information Center

Brekke, Stewart E.

2003-01-01

Points out the importance of problem solving as a fundamental skill and how students struggle with problem solving in physics courses. Describes a workbook developed as a solution to students' struggles that features simple exercises and advanced problem solving. (Contains 12 references.) (Author/YDS)

Quantum dot laser optimization: selectively doped layers

NASA Astrophysics Data System (ADS)

Korenev, Vladimir V.; Konoplev, Sergey S.; Savelyev, Artem V.; Shernyakov, Yurii M.; Maximov, Mikhail V.; Zhukov, Alexey E.

2016-08-01

Edge emitting quantum dot (QD) lasers are discussed. It has been recently proposed to use modulation p-doping of the layers that are adjacent to QD layers in order to control QD's charge state. Experimentally it has been proven useful to enhance ground state lasing and suppress the onset of excited state lasing at high injection. These results have been also confirmed with numerical calculations involving solution of drift-diffusion equations. However, deep understanding of physical reasons for such behavior and laser optimization requires analytical approaches to the problem. In this paper, under a set of assumptions we provide an analytical model that explains major effects of selective p-doping. Capture rates of elections and holes can be calculated by solving Poisson equations for electrons and holes around the charged QD layer. The charge itself is ruled by capture rates and selective doping concentration. We analyzed this self-consistent set of equations and showed that it can be used to optimize QD laser performance and to explain underlying physics.

Research on natural lighting in reading spaces of university libraries in Jinan under the perspective of energy-efficiency

NASA Astrophysics Data System (ADS)

Yang, Zengzhang

2017-11-01

The natural lighting design in the reading spaces of university libraries not only influences physical and mental health of readers but also concerns the energy consumption of the libraries. The scientific and rational design of natural lighting is the key to the design of energy saving for physical environment of the reading space. The paper elaborates the present situation and existed problems of natural lighting in reading spaces of university libraries across Jinan region based on characteristics of light climate of Jinan region and concrete utilization of reading spaces in university libraries, and combining field measurement, survey, research and data analysis of reading spaces in Shandong Women’s University’s library. The paper, under the perspective of energy-efficiency, puts forward proposals to improve natural lighting in the reading spaces of university libraries from five aspects, such as adjustment of interior layout, optimization of outer windows design, employment of the reflector panel, design lighting windows on inner walls and utilization of adjustable sun shading facilities.

Neuromorphic computing enabled by physics of electron spins: Prospects and perspectives

NASA Astrophysics Data System (ADS)

Sengupta, Abhronil; Roy, Kaushik

2018-03-01

“Spintronics” refers to the understanding of the physics of electron spin-related phenomena. While most of the significant advancements in this field has been driven primarily by memory, recent research has demonstrated that various facets of the underlying physics of spin transport and manipulation can directly mimic the functionalities of the computational primitives in neuromorphic computation, i.e., the neurons and synapses. Given the potential of these spintronic devices to implement bio-mimetic computations at very low terminal voltages, several spin-device structures have been proposed as the core building blocks of neuromorphic circuits and systems to implement brain-inspired computing. Such an approach is expected to play a key role in circumventing the problems of ever-increasing power dissipation and hardware requirements for implementing neuro-inspired algorithms in conventional digital CMOS technology. Perspectives on spin-enabled neuromorphic computing, its status, and challenges and future prospects are outlined in this review article.

Sgr A* as Source of the Positrons Observed in the Galactic Center Region

NASA Astrophysics Data System (ADS)

Jean, Pierre; Guessoum, Nidhal; Ferrière, Katia

2017-01-01

We explore the possibility that a substantial fraction of the positrons observed to annihilate in the central region of our Galaxy come from the supermassive black hole Sgr A* that lies at the center. This idea was proposed by several authors, but the propagation of the emitted positrons into the bulge and beyond remained a serious problem for models of the origin of GC positrons. We assume models of positron production with different energies. The propagation of positrons from their production site is followed in detail with Monte-Carlo simulations, taking into account the physical conditions of the propagation regions as well as various physical interactions. Using the known physics of positron annihilation in astrophysical environments, we calculate the properties of the annihilation emission (time evolution and spatial distribution) for the different models under consideration. We present the results of these simulations and the conclusions/constraints that can be inferred from them.

Teaching Physics from a Reduced Gravity Environment

NASA Astrophysics Data System (ADS)

Benge, Raymond D.; Young, C.; Davis, S.; Worley, A.; Smith, L.; Gell, A.

2010-01-01

This poster reports on an educational experiment flown in January 2009 as part of NASA's Microgravity University program. The experiment flown was an investigation into the properties of harmonic oscillators in reduced gravity. Harmonic oscillators are studied in every introductory physics class. The equation for the period of a harmonic oscillator does not include the acceleration due to gravity, so the period should be independent of gravity. However, the equation for the period of a pendulum does include the acceleration due to gravity, so the period of a pendulum should appear longer under reduced gravity (such as lunar or Martian gravity) and shorter under hyper-gravity. Typical homework problems for introductory physics classes ask questions such as "What would be the period of oscillation if this experiment were performed on the Moon or Mars?” This gives students a chance to actually see the effects predicted by the equations. These environments can be simulated aboard an aircraft. Video of the experiments being performed aboard the aircraft is to be used in introductory physics classes. Students will be able to record information from watching the experiment performed aboard the aircraft in a similar manner to how they collect data in the laboratory. They can then determine if the experiment matches theory. Video and an experimental procedure are being prepared based upon this flight, and these materials will be available for download by faculty anywhere with access to the internet who wish to use the experiment in their own classrooms in both college and high school physics classes.

An issue encountered in solving problems in electricity and magnetism: curvilinear coordinates

NASA Astrophysics Data System (ADS)

Gülçiçek, Çağlar; Damlı, Volkan

2016-11-01

In physics lectures on electromagnetic theory and mathematical methods, physics teacher candidates have some difficulties with curvilinear coordinate systems. According to our experience, based on both in-class interactions and teacher candidates’ answers in test papers, they do not seem to have understood the variables in curvilinear coordinate systems very well. For this reason, the problems that physics teacher candidates have with variables in curvilinear coordinate systems have been selected as a study subject. The aim of this study is to find the physics teacher candidates’ problems with determining the variables of drawn shapes, and problems with drawing shapes based on given variables in curvilinear coordinate systems. Two different assessment tests were used in the study to achieve this aim. The curvilinear coordinates drawing test (CCDrT) was used to discover their problems related to drawing shapes, and the curvilinear coordinates detection test (CCDeT) was used to find out about problems related to determining variables. According to the findings obtained from both tests, most physics teacher candidates have problems with the ϕ variable, while they have limited problems with the r variable. Questions that are mostly answered wrongly have some common properties, such as value. According to inferential statistics, there is no significant difference between the means of the CCDeT and CCDrT scores. The mean of the CCDeT scores is only 4.63 and the mean of the CCDrT is only 4.66. Briefly, we can say that most physics teacher candidates have problems with drawing a shape using the variables of curvilinear coordinate systems or in determining the variables of drawn shapes. Part of this study was presented at the XI. National Science and Mathematics Education Congress (UFBMEK) in 2014.

Resource Letter RPS-1: Research in problem solving

NASA Astrophysics Data System (ADS)

Hsu, Leonardo; Brewe, Eric; Foster, Thomas M.; Harper, Kathleen A.

2004-09-01

This Resource Letter provides a guide to the literature on research in problem solving, especially in physics. The references were compiled with two audiences in mind: physicists who are (or might become) engaged in research on problem solving, and physics instructors who are interested in using research results to improve their students' learning of problem solving. In addition to general references, journal articles and books are cited for the following topics: cognitive aspects of problem solving, expert-novice problem-solver characteristics, problem solving in mathematics, alternative problem types, curricular interventions, and the use of computers in problem solving.

Using gender-based analyses to understand physical inactivity among women in Yellowstone County, Montana.

PubMed

Duin, Diane K; Golbeck, Amanda L; Keippel, April Ennis; Ciemins, Elizabeth; Hanson, Hillary; Neary, Tracy; Fink, Heather

2015-08-01

Physical inactivity contributes to many health problems. Gender, the socially constructed roles and activities deemed appropriate for men and women, is an important factor in women's physical inactivity. To better understand how gender influences participation in leisure-time physical activity, a gender analysis was conducted using sex-disaggregated data from a county-wide health assessment phone survey and a qualitative analysis of focus group transcripts. From this gender analysis, several gender-based constraints emerged, including women's roles as caregivers, which left little time or energy for physical activity, women's leisure time activities and hobbies, which were less active than men's hobbies, and expectations for women's appearance that made them uncomfortable sweating in front of strangers. Gender-based opportunities included women's enjoyment of activity as a social connection, less rigid gender roles for younger women, and a sense of responsibility to set a good example for their families. The gender analysis was used to gain a deeper understanding of gender-based constraints and opportunities related to physical activity. This understanding is being used in the next step of our research to develop a gender-specific intervention to promote physical activity in women that addresses the underlying causes of physical inactivity through accommodation or transformation of those gender norms. Copyright © 2014 Elsevier Ltd. All rights reserved.

A stochastic optimization model under modeling uncertainty and parameter certainty for groundwater remediation design--part I. Model development.

PubMed

He, L; Huang, G H; Lu, H W

2010-04-15

Solving groundwater remediation optimization problems based on proxy simulators can usually yield optimal solutions differing from the "true" ones of the problem. This study presents a new stochastic optimization model under modeling uncertainty and parameter certainty (SOMUM) and the associated solution method for simultaneously addressing modeling uncertainty associated with simulator residuals and optimizing groundwater remediation processes. This is a new attempt different from the previous modeling efforts. The previous ones focused on addressing uncertainty in physical parameters (i.e. soil porosity) while this one aims to deal with uncertainty in mathematical simulator (arising from model residuals). Compared to the existing modeling approaches (i.e. only parameter uncertainty is considered), the model has the advantages of providing mean-variance analysis for contaminant concentrations, mitigating the effects of modeling uncertainties on optimal remediation strategies, offering confidence level of optimal remediation strategies to system designers, and reducing computational cost in optimization processes. 2009 Elsevier B.V. All rights reserved.

Physical activity is associated with the physical, psychological, social and environmental quality of life in people with mental health problems in a low resource setting.

PubMed

Vancampfort, Davy; Van Damme, Tine; Probst, Michel; Firth, Joseph; Stubbs, Brendon; Basangwa, David; Mugisha, James

2017-12-01

There is a growing recognition of the importance of encouraging patients with mental health problems to become more active as an efficacious strategy to reduce the disability-associated burden. The aim of the current study was to investigate if there are differences in quality of life (QoL) outcomes between people with mental health problems that do and do not meet the recommendations of 150min per week of physical activity. 109 (36♀) Ugandan in- and outpatients (mean age = 34.2 ± 10.2 years) (depression = 7, bipolar disorder = 31, schizophrenia = 21, alcohol use disorder = 50) completed the Physical Activity Vital Sign (PAVS) method and World Health Organization Quality of Life Assessment brief version. Those who did not achieve the minimum physical activity recommendations as assessed by the PAVS (n = 63) had a lower physical, psychological, social and environmental QoL. The current data offer further evidence that the PAVS method might be an important risk identification tool in people with mental health problems. The feasibility and acceptability of the PAVS may help promote the importance of physical activity assessment and prescription as a core part of the treatment of mental health problems in LMICs. Copyright © 2017 Elsevier B.V. All rights reserved.

When procedures discourage insight: epistemological consequences of prompting novice physics students to construct force diagrams

NASA Astrophysics Data System (ADS)

Kuo, Eric; Hallinen, Nicole R.; Conlin, Luke D.

2017-05-01

One aim of school science instruction is to help students become adaptive problem solvers. Though successful at structuring novice problem solving, step-by-step problem-solving frameworks may also constrain students' thinking. This study utilises a paradigm established by Heckler [(2010). Some consequences of prompting novice physics students to construct force diagrams. International Journal of Science Education, 32(14), 1829-1851] to test how cuing the first step in a standard framework affects undergraduate students' approaches and evaluation of solutions in physics problem solving. Specifically, prompting the construction of a standard diagram before problem solving increases the use of standard procedures, decreasing the use of a conceptual shortcut. Providing a diagram prompt also lowers students' ratings of informal approaches to similar problems. These results suggest that reminding students to follow typical problem-solving frameworks limits their views of what counts as good problem solving.

Abraham Pais Prize Lecture: Shifting Problems and Boundaries in the History of Modern Physics

NASA Astrophysics Data System (ADS)

Nye, Mary-Jo

A long established category of study in the history of science is the ``history of physical sciences.'' It is a category that immediately begs the question of disciplinary boundaries for the problems and subjects addressed in historical inquiry. As a historian of the physical sciences, I often have puzzled over disciplinary boundaries and the means used to create or justify them. Scientists most often have been professionally identified with specific institutionalized fields since the late 19th century, but the questions they ask and the problems they solve are not neatly carved up by disciplinary perimeters. Like institutional departments or professorships, the Nobel Prizes in the 20th century often have delineated the scope of ``Physics'' or ``Chemistry'' (and ``Physiology or Medicine''), but the Prizes do not reflect disciplinary rigidity, despite some standard core subjects. In this paper I examine trends in Nobel Prize awards that indicate shifts in problem solving and in boundaries in twentieth century physics, tying those developments to changing themes in the history of physics and physical science in recent decades.

Influence of Learning Strategy of Cognitive Conflict on Student Misconception in Computational Physics Course

NASA Astrophysics Data System (ADS)

Akmam, A.; Anshari, R.; Amir, H.; Jalinus, N.; Amran, A.

2018-04-01

Misconception is one of the factors causing students are not suitable in to choose a method for problem solving. Computational Physics course is a major subject in the Department of Physics FMIPA UNP Padang. The problem in Computational Physics learning lately is that students have difficulties in constructing knowledge. The indication of this problem was the student learning outcomes do not achieve mastery learning. The root of the problem is the ability of students to think critically weak. Student critical thinking can be improved using cognitive by conflict learning strategies. The research aims to determine the effect of cognitive conflict learning strategy to student misconception on the subject of Computational Physics Course at the Department of Physics, Faculty of Mathematics and Science, Universitas Negeri Padang. The experimental research design conducted after-before design cycles with a sample of 60 students by cluster random sampling. Data were analyzed using repeated Anova measurements. The cognitive conflict learning strategy has a significant effect on student misconception in the subject of Computational Physics Course.

A modified active appearance model based on an adaptive artificial bee colony.

PubMed

Abdulameer, Mohammed Hasan; Sheikh Abdullah, Siti Norul Huda; Othman, Zulaiha Ali

2014-01-01

Active appearance model (AAM) is one of the most popular model-based approaches that have been extensively used to extract features by highly accurate modeling of human faces under various physical and environmental circumstances. However, in such active appearance model, fitting the model with original image is a challenging task. State of the art shows that optimization method is applicable to resolve this problem. However, another common problem is applying optimization. Hence, in this paper we propose an AAM based face recognition technique, which is capable of resolving the fitting problem of AAM by introducing a new adaptive ABC algorithm. The adaptation increases the efficiency of fitting as against the conventional ABC algorithm. We have used three datasets: CASIA dataset, property 2.5D face dataset, and UBIRIS v1 images dataset in our experiments. The results have revealed that the proposed face recognition technique has performed effectively, in terms of accuracy of face recognition.

Judgments of natural and anomalous trajectories in the presence and absence of motion

NASA Technical Reports Server (NTRS)

Kaiser, M. K.; Proffitt, D. R.; Anderson, K.

1985-01-01

Three experiments using McCloskey's curved tube problem, in which people are asked to predict the path that a ball takes when it is shot through a tube curved in a 'C' or spiral, are reported. The first experiment compared the perceptual and representational competencies of observers in recognizing the natural trajectory of the ball, and the second examined the competencies of children on this problem. The third experiment attempted to enhance the representational competence of observers by encouraging them to use a mental imagery approach to the problem. The subjects were presented with both on-going events and with static representations of the event. Men performed better than women under both these conditions, a result not attributable to formal instruction in physics. Children showed no gender effect. The use of mental imagery did not enhance performance on the static test.

Target Fishing for Chemical Compounds using Target-Ligand Activity data and Ranking based Methods

PubMed Central

Wale, Nikil; Karypis, George

2009-01-01

In recent years the development of computational techniques that identify all the likely targets for a given chemical compound, also termed as the problem of Target Fishing, has been an active area of research. Identification of likely targets of a chemical compound helps to understand problems such as toxicity, lack of efficacy in humans, and poor physical properties associated with that compound in the early stages of drug discovery. In this paper we present a set of techniques whose goal is to rank or prioritize targets in the context of a given chemical compound such that most targets that this compound may show activity against appear higher in the ranked list. These methods are based on our extensions to the SVM and Ranking Perceptron algorithms for this problem. Our extensive experimental study shows that the methods developed in this work outperform previous approaches by 2% to 60% under different evaluation criterions. PMID:19764745

Radiative-conductive inverse problem for lumped parameter systems

NASA Astrophysics Data System (ADS)

Alifanov, O. M.; Nenarokomov, A. V.; Gonzalez, V. M.

2008-11-01

The purpose of this paper is to introduce a iterative regularization method in the research of radiative and thermal properties of materials with applications in the design of Thermal Control Systems (TCS) of spacecrafts. In this paper the radiative and thermal properties (emissivity and thermal conductance) of a multilayered thermal-insulating blanket (MLI), which is a screen-vacuum thermal insulation as a part of the (TCS) for perspective spacecrafts, are estimated. Properties of the materials under study are determined in the result of temperature and heat flux measurement data processing based on the solution of the Inverse Heat Transfer Problem (IHTP) technique. Given are physical and mathematical models of heat transfer processes in a specimen of the multilayered thermal-insulating blanket located in the experimental facility. A mathematical formulation of the inverse heat conduction problem is presented too. The practical testing were performed for specimen of the real MLI.

Study of multilayer thermal insulation by inverse problems method

NASA Astrophysics Data System (ADS)

Alifanov, O. M.; Nenarokomov, A. V.; Gonzalez, V. M.

2009-11-01

The purpose of this paper is to introduce a new method in the research of radiative and thermal properties of materials with further applications in the design of thermal control systems (TCS) of spacecrafts. In this paper the radiative and thermal properties (emissivity and thermal conductance) of a multilayered thermal-insulating blanket (MLI), which is a screen-vacuum thermal insulation as a part of the TCS for perspective spacecrafts, are estimated. Properties of the materials under study are determined in the result of temperature and heat flux measurement data processing based on the solution of the inverse heat transfer problem (IHTP) technique. Given are physical and mathematical models of heat transfer processes in a specimen of the multilayered thermal-insulating blanket located in the experimental facility. A mathematical formulation of the inverse heat conduction problem is presented as well. The practical approves were made for specimen of the real MLI.

Fetal alcohol spectrum disorders--a case-control study from India.

PubMed

Nayak, Raghavendra; Murthy, Pratima; Girimaji, Satish; Navaneetham, Jamuna

2012-02-01

Maternal alcohol abuse during pregnancy can lead to fetal neurotoxicity and fetal alcohol spectrum disorder (FASD). To compare the clinical features and neurobehavioral profiles of children exposed to alcohol during pregnancy with controls. Children exposed to alcohol in utero (n = 26) and 27-years age- and sex-matched controls were compared on FAS facial features, minor physical anomalies (MPAs), anthropometric measures, behavioral problems and intellectual functioning. MPAs were more common in cases (p = 0.001). Among FAS facial features, only philtrum smoothness varied significantly between the groups (p = 0.001). Behavioral problems (on Childhood Behavior Check List) were more pronounced (p = 0.001) and intellectual functioning significantly poorer in cases (p = 0.001) compared to controls. Children prenatally exposed to alcohol manifest several neurobehavioral problems compared to controls. Underlying malnutrition may have altered some of the clinical findings.

Finite cover method with mortar elements for elastoplasticity problems

NASA Astrophysics Data System (ADS)

Kurumatani, M.; Terada, K.

2005-06-01

Finite cover method (FCM) is extended to elastoplasticity problems. The FCM, which was originally developed under the name of manifold method, has recently been recognized as one of the generalized versions of finite element methods (FEM). Since the mesh for the FCM can be regular and squared regardless of the geometry of structures to be analyzed, structural analysts are released from a burdensome task of generating meshes conforming to physical boundaries. Numerical experiments are carried out to assess the performance of the FCM with such discretization in elastoplasticity problems. Particularly to achieve this accurately, the so-called mortar elements are introduced to impose displacement boundary conditions on the essential boundaries, and displacement compatibility conditions on material interfaces of two-phase materials or on joint surfaces between mutually incompatible meshes. The validity of the mortar approximation is also demonstrated in the elastic-plastic FCM.

Problem Solving, Scaffolding and Learning

ERIC Educational Resources Information Center

Lin, Shih-Yin

2012-01-01

Helping students to construct robust understanding of physics concepts and develop good solving skills is a central goal in many physics classrooms. This thesis examine students' problem solving abilities from different perspectives and explores strategies to scaffold students' learning. In studies involving analogical problem solving…

Childhood Physical and Sexual Abuse and Social Network Patterns on Social Media: Associations With Alcohol Use and Problems Among Young Adult Women

PubMed Central

Oshri, Assaf; Himelboim, Itai; Kwon, Josephine A.; Sutton, Tara E.; Mackillop, James

2015-01-01

Objective: The aim of the present study was to examine the links between severities of child abuse (physical vs. sexual), and alcohol use versus problems via social media (Facebook) peer connection structures. Method: A total of 318 undergraduate female students at a public university in the United States reported severity of child abuse experiences and current alcohol use and problems. Social network data were obtained directly from the individuals’ Facebook network. Results: Severity of childhood physical abuse was positively linked to alcohol use and problems via eigenvector centrality, whereas severity of childhood sexual abuse was negatively linked to alcohol use and problems via clustering coefficient. Conclusions: Childhood physical and sexual abuse were linked positively and negatively, respectively, to online social network patterns associated with alcohol use and problems. The study suggests the potential utility of these online network patterns as risk indices and ultimately using social media as a platform for targeted preventive interventions. PMID:26562592

Childhood Physical and Sexual Abuse and Social Network Patterns on Social Media: Associations With Alcohol Use and Problems Among Young Adult Women.

PubMed

Oshri, Assaf; Himelboim, Itai; Kwon, Josephine A; Sutton, Tara E; Mackillop, James

2015-11-01

The aim of the present study was to examine the links between severities of child abuse (physical vs. sexual), and alcohol use versus problems via social media (Facebook) peer connection structures. A total of 318 undergraduate female students at a public university in the United States reported severity of child abuse experiences and current alcohol use and problems. Social network data were obtained directly from the individuals' Facebook network. Severity of childhood physical abuse was positively linked to alcohol use and problems via eigenvector centrality, whereas severity of childhood sexual abuse was negatively linked to alcohol use and problems via clustering coefficient. Childhood physical and sexual abuse were linked positively and negatively, respectively, to online social network patterns associated with alcohol use and problems. The study suggests the potential utility of these online network patterns as risk indices and ultimately using social media as a platform for targeted preventive interventions.

A prospectus on kinetic heliophysics

NASA Astrophysics Data System (ADS)

Howes, Gregory G.

2017-05-01

Under the low density and high temperature conditions typical of heliospheric plasmas, the macroscopic evolution of the heliosphere is strongly affected by the kinetic plasma physics governing fundamental microphysical mechanisms. Kinetic turbulence, collisionless magnetic reconnection, particle acceleration, and kinetic instabilities are four poorly understood, grand-challenge problems that lie at the new frontier of kinetic heliophysics. The increasing availability of high cadence and high phase-space resolution measurements of particle velocity distributions by current and upcoming spacecraft missions and of massively parallel nonlinear kinetic simulations of weakly collisional heliospheric plasmas provides the opportunity to transform our understanding of these kinetic mechanisms through the full utilization of the information contained in the particle velocity distributions. Several major considerations for future investigations of kinetic heliophysics are examined. Turbulent dissipation followed by particle heating is highlighted as an inherently two-step process in weakly collisional plasmas, distinct from the more familiar case in fluid theory. Concerted efforts must be made to tackle the big-data challenge of visualizing the high-dimensional (3D-3V) phase space of kinetic plasma theory through physics-based reductions. Furthermore, the development of innovative analysis methods that utilize full velocity-space measurements, such as the field-particle correlation technique, will enable us to gain deeper insight into these four grand-challenge problems of kinetic heliophysics. A systems approach to tackle the multi-scale problem of heliophysics through a rigorous connection between the kinetic physics at microscales and the self-consistent evolution of the heliosphere at macroscales will propel the field of kinetic heliophysics into the future.

A prospectus on kinetic heliophysics

PubMed Central

2017-01-01

Under the low density and high temperature conditions typical of heliospheric plasmas, the macroscopic evolution of the heliosphere is strongly affected by the kinetic plasma physics governing fundamental microphysical mechanisms. Kinetic turbulence, collisionless magnetic reconnection, particle acceleration, and kinetic instabilities are four poorly understood, grand-challenge problems that lie at the new frontier of kinetic heliophysics. The increasing availability of high cadence and high phase-space resolution measurements of particle velocity distributions by current and upcoming spacecraft missions and of massively parallel nonlinear kinetic simulations of weakly collisional heliospheric plasmas provides the opportunity to transform our understanding of these kinetic mechanisms through the full utilization of the information contained in the particle velocity distributions. Several major considerations for future investigations of kinetic heliophysics are examined. Turbulent dissipation followed by particle heating is highlighted as an inherently two-step process in weakly collisional plasmas, distinct from the more familiar case in fluid theory. Concerted efforts must be made to tackle the big-data challenge of visualizing the high-dimensional (3D-3V) phase space of kinetic plasma theory through physics-based reductions. Furthermore, the development of innovative analysis methods that utilize full velocity-space measurements, such as the field-particle correlation technique, will enable us to gain deeper insight into these four grand-challenge problems of kinetic heliophysics. A systems approach to tackle the multi-scale problem of heliophysics through a rigorous connection between the kinetic physics at microscales and the self-consistent evolution of the heliosphere at macroscales will propel the field of kinetic heliophysics into the future. PMID:29104421

The use of multiple representations and visualizations in student learning of introductory physics: An example from work and energy

NASA Astrophysics Data System (ADS)

Zou, Xueli

In the past three decades, physics education research has primarily focused on student conceptual understanding; little work has been conducted to investigate student difficulties in problem solving. In cognitive science and psychology, however, extensive studies have explored the differences in problem solving between experts and naive students. A major finding indicates that experts often apply qualitative representations in problem solving, but that novices use an equation-centered method. This dissertation describes investigations into the use of multiple representations and visualizations in student understanding and problem solving with the concepts of work and energy. A multiple-representation strategy was developed to help students acquire expertise in solving work-energy problems. In this approach, a typical work-energy problem is considered as a physical process. The process is first described in words-the verbal representation of the process. Next, a sketch or a picture, called a pictorial representation, is used to represent the process. This is followed by work-energy bar charts-a physical representation of the same processes. Finally, this process is represented mathematically by using a generalized work-energy equation. In terms of the multiple representations, the goal of solving a work- energy problem is to represent the physical process the more intuitive pictorial and diagrammatic physical representations. Ongoing assessment of student learning indicates that this multiple-representation technique is more effective than standard instruction methods in student problem solving. visualize this difficult-to-understand concept, a guided- inquiry learning activity using a pair of model carts and an experiment problem using a sandbag were developed. Assessment results have shown that these research-based materials are effective in helping students visualize this concept and give a pictorial idea of ``where the kinetic energy goes'' during inelastic collisions. The research and curriculum development was conducted in the context of the introductory calculus-based physics course. Investigations were carried out using common physics education research tools, including open-ended surveys, written test questions, and individual student interviews.

Numerical Ergonomics Analysis in Operation Environment of CNC Machine

NASA Astrophysics Data System (ADS)

Wong, S. F.; Yang, Z. X.

2010-05-01

The performance of operator will be affected by different operation environments [1]. Moreover, poor operation environment may cause health problems of the operator [2]. Physical and psychological considerations are two main factors that will affect the performance of operator under different conditions of operation environment. In this paper, applying scientific and systematic methods find out the pivot elements in the field of physical and psychological factors. There are five main factors including light, temperature, noise, air flow and space that are analyzed. A numerical ergonomics model has been built up regarding the analysis results which can support to advance the design of operation environment. Moreover, the output of numerical ergonomic model can provide the safe, comfortable, more productive conditions for the operator.

Work of the Tamm-Sakharov group on the first hydrogen bomb

NASA Astrophysics Data System (ADS)

Ritus, V. I.

2014-09-01

This review is an extended version of a report delivered at a session of the Department of Physical Sciences, the Department of Energetics, Mechanical Engineering, Mechanics, and Control Processes, and the Coordination Council on Technical Sciences of the RAS devoted to the 60th anniversary of the first hydrogen bomb test. The significant physical ideas suggested by A D Sakharov and V L Ginzburg underlying our first hydrogen bomb, RDS-6s, and numerous concrete problems and difficulties that had to be solved and overcome in designing thermonuclear weapons are presented. The understanding of the country's leaders and the Atomic Project managers of the exceptional role of fundamental science in the appearance and implementation of our scientists' concrete ideas and suggestions is emphasized.

Intellectual disability and co-occurring mental health and physical disorders in aggressive behaviour.

PubMed

Crocker, A G; Prokić, A; Morin, D; Reyes, A

2014-11-01

Mental and physical health problems are more prevalent among individuals with an intellectual disability (ID) than in the general population. Studies suggest that there may be significant associations between these co-occurring disorders and aggressive behaviour, but few studies have taken into account multiple mental and physical problems, as well as their level of severity. The main goal of this study was to identify the associations between different types of aggressive behaviour and various types of physical and mental health problems. These associations were explored through a cross-sectional study of 296 adult men and women with mild or moderate ID living in the community and receiving ID services. Information was gathered through interviews with ID participants, case managers and file review. The results show that individuals with ID who have more mental and physical health problems have higher odds of displaying aggressive behaviour than those with fewer and less severe physical health problems. These results can help guide future prevention and intervention strategies for persons with ID who display aggressive behaviour or who are at risk of become aggressive. © 2013 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.

Analysing the Problems of Science Teachers That They Encounter While Teaching Physics Education

ERIC Educational Resources Information Center

Demir, Cihat; Sincar, Burhan; Çelik, Ridvan

2015-01-01

Even though physical science is very important in our daily lives, it is insufficiently understood by students. In order for students to get a better physical education, the teachers who have given physics lesson should first eliminated the problems that they face during the teaching process. The aim of this survey is to specify the matters…

Development of the 3-SET 4P questionnaire for evaluating former ICU patients' physical and psychosocial problems over time: a pilot study.

PubMed

Akerman, Eva; Fridlund, Bengt; Ersson, Anders; Granberg-Axéll, Anetth

2009-04-01

Current studies reveal a lack of consensus for the evaluation of physical and psychosocial problems after ICU stay and their changes over time. The aim was to develop and evaluate the validity and reliability of a questionnaire for assessing physical and psychosocial problems over time for patients following ICU recovery. Thirty-nine patients completed the questionnaire, 17 were retested. The questionnaire was constructed in three sets: physical problems, psychosocial problems and follow-up care. Face and content validity were tested by nurses, researchers and patients. The questionnaire showed good construct validity in all three sets and had strong factor loadings (explained variance >70%, factor loadings >0.5) for all three sets. There was good concurrent validity compared with the SF 12 (r(s)>0.5). Internal consistency was shown to be reliable (Cronbach's alpha 0.70-0.85). Stability reliability on retesting was good for the physical and psychosocial sets (r(s)>0.5). The 3-set 4P questionnaire was a first step in developing an instrument for assessment of former ICU patients' problems over time. The sample size was small and thus, further studies are needed to confirm these findings.

Diagnosis by integrating model-based reasoning with knowledge-based reasoning

NASA Technical Reports Server (NTRS)

Bylander, Tom

1988-01-01

Our research investigates how observations can be categorized by integrating a qualitative physical model with experiential knowledge. Our domain is diagnosis of pathologic gait in humans, in which the observations are the gait motions, muscle activity during gait, and physical exam data, and the diagnostic hypotheses are the potential muscle weaknesses, muscle mistimings, and joint restrictions. Patients with underlying neurological disorders typically have several malfunctions. Among the problems that need to be faced are: the ambiguity of the observations, the ambiguity of the qualitative physical model, correspondence of the observations and hypotheses to the qualitative physical model, the inherent uncertainty of experiential knowledge, and the combinatorics involved in forming composite hypotheses. Our system divides the work so that the knowledge-based reasoning suggests which hypotheses appear more likely than others, the qualitative physical model is used to determine which hypotheses explain which observations, and another process combines these functionalities to construct a composite hypothesis based on explanatory power and plausibility. We speculate that the reasoning architecture of our system is generally applicable to complex domains in which a less-than-perfect physical model and less-than-perfect experiential knowledge need to be combined to perform diagnosis.

From quantum foundations to applications and back.

PubMed

Gisin, Nicolas; Fröwis, Florian

2018-07-13

Quantum non-locality has been an extremely fruitful subject of research, leading the scientific revolution towards quantum information science, in particular, to device-independent quantum information processing. We argue that the time is ripe to work on another basic problem in the foundations of quantum physics, the quantum measurement problem, which should produce good physics in theoretical, mathematical, experimental and applied physics. We briefly review how quantum non-locality contributed to physics (including some outstanding open problems) and suggest ways in which questions around macroscopic quantumness could equally contribute to all aspects of physics.This article is part of a discussion meeting issue 'Foundations of quantum mechanics and their impact on contemporary society'. © 2018 The Author(s).

Silicon carbide: A unique platform for metal-oxide-semiconductor physics

NASA Astrophysics Data System (ADS)

Liu, Gang; Tuttle, Blair R.; Dhar, Sarit

2015-06-01

A sustainable energy future requires power electronics that can enable significantly higher efficiencies in the generation, distribution, and usage of electrical energy. Silicon carbide (4H-SiC) is one of the most technologically advanced wide bandgap semiconductor that can outperform conventional silicon in terms of power handling, maximum operating temperature, and power conversion efficiency in power modules. While SiC Schottky diode is a mature technology, SiC power Metal Oxide Semiconductor Field Effect Transistors are relatively novel and there is large room for performance improvement. Specifically, major initiatives are under way to improve the inversion channel mobility and gate oxide stability in order to further reduce the on-resistance and enhance the gate reliability. Both problems relate to the defects near the SiO2/SiC interface, which have been the focus of intensive studies for more than a decade. Here we review research on the SiC MOS physics and technology, including its brief history, the state-of-art, and the latest progress in this field. We focus on the two main scientific problems, namely, low channel mobility and bias temperature instability. The possible mechanisms behind these issues are discussed at the device physics level as well as the atomic scale, with the support of published physical analysis and theoretical studies results. Some of the most exciting recent progress in interface engineering for improving the channel mobility and fundamental understanding of channel transport is reviewed.

Psychiatric, Psychosocial, and Physical Health Correlates of Co-Occurring Cannabis Use Disorders and Nicotine Dependence

PubMed Central

Peters, Erica N.; Schwartz, Robert P.; Wang, Shuai; O’Grady, Kevin E.; Blanco, Carlos

2013-01-01

Background Several gaps in the literature on individuals with co-occurring cannabis and tobacco use exist, including the extent of psychiatric, psychosocial, and physical health problems. We examine these gaps in an epidemiological study, the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), of a large, nationally representative sample. Methods The sample was drawn from Wave 2 NESARC respondents (N = 34,653). Adults with current cannabis use disorders and nicotine dependence (CUD + ND) (n = 74), CUD only (n = 100), and ND only (n = 3424) were compared on psychiatric disorders, psychosocial correlates (e.g., binge drinking; partner violence), and physical health correlates (e.g., medical conditions). Results Relative to those with CUD only, respondents with CUD + ND were significantly more likely to meet criteria for bipolar disorder, Clusters A and B personality disorders, and narcissistic personality disorder, and reported engaging in a significantly higher number of antisocial behaviors. Relative to those with ND only, respondents with CUD + ND were significantly more likely to meet criteria for bipolar disorder, anxiety disorders, and paranoid, schizotypal, narcissistic, and borderline personality disorders; were significantly more likely to report driving under the influence of alcohol and being involved in partner violence; and reported engaging in a significantly higher number of antisocial behaviors. CUD + ND was not associated with physical health correlates. Conclusions Poor treatment outcomes for adults with co-occurring cannabis use disorders and nicotine dependence may be explained in part by differences in psychiatric and psychosocial problems. PMID:24183498

Psychiatric, psychosocial, and physical health correlates of co-occurring cannabis use disorders and nicotine dependence.

PubMed

Peters, Erica N; Schwartz, Robert P; Wang, Shuai; O'Grady, Kevin E; Blanco, Carlos

2014-01-01

Several gaps in the literature on individuals with co-occurring cannabis and tobacco use exist, including the extent of psychiatric, psychosocial, and physical health problems. We examine these gaps in an epidemiological study, the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), of a large, nationally representative sample. The sample was drawn from Wave 2 NESARC respondents (N=34,653). Adults with current cannabis use disorders and nicotine dependence (CUD+ND) (n=74), CUD only (n=100), and ND only (n=3424) were compared on psychiatric disorders, psychosocial correlates (e.g., binge drinking; partner violence), and physical health correlates (e.g., medical conditions). Relative to those with CUD only, respondents with CUD+ND were significantly more likely to meet criteria for bipolar disorder, Clusters A and B personality disorders, and narcissistic personality disorder, and reported engaging in a significantly higher number of antisocial behaviors. Relative to those with ND only, respondents with CUD+ND were significantly more likely to meet criteria for bipolar disorder, anxiety disorders, and paranoid, schizotypal, narcissistic, and borderline personality disorders; were significantly more likely to report driving under the influence of alcohol and being involved in partner violence; and reported engaging in a significantly higher number of antisocial behaviors. CUD+ND was not associated with physical health correlates. Poor treatment outcomes for adults with co-occurring cannabis use disorders and nicotine dependence may be explained in part by differences in psychiatric and psychosocial problems. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Explicit reflection in an introductory physics course

NASA Astrophysics Data System (ADS)

Scott, Michael Lee

This dissertation details a classroom intervention that supplements assigned in-class problems in weekly problem sets with reflective activities that are aimed to assist in knowledge integration. Using the framework of cognitive load theory, this intervention should assist in schema acquisition leading to (1) students recognizing the use and appropriately applying physical concepts across different problem contexts, and (2) enhanced physics understanding of students resulting in improved class performance. The intervention was embedded in the discussion component of an introductory, university physics course, and spanned a 14-week period. Evaluation of the intervention was based on the relative performance between a control and treatment group. Instruments used in this study to assess performance included the Force Concept Inventory (FCI), a physics problem categorization test, and four class exams. A full discussion of this implementation and the accompanying measures will be given. Possible limitations to this study and lines of future research will be proposed.

Multi-objective optimisation and decision-making of space station logistics strategies

NASA Astrophysics Data System (ADS)

Zhu, Yue-he; Luo, Ya-zhong

2016-10-01

Space station logistics strategy optimisation is a complex engineering problem with multiple objectives. Finding a decision-maker-preferred compromise solution becomes more significant when solving such a problem. However, the designer-preferred solution is not easy to determine using the traditional method. Thus, a hybrid approach that combines the multi-objective evolutionary algorithm, physical programming, and differential evolution (DE) algorithm is proposed to deal with the optimisation and decision-making of space station logistics strategies. A multi-objective evolutionary algorithm is used to acquire a Pareto frontier and help determine the range parameters of the physical programming. Physical programming is employed to convert the four-objective problem into a single-objective problem, and a DE algorithm is applied to solve the resulting physical programming-based optimisation problem. Five kinds of objective preference are simulated and compared. The simulation results indicate that the proposed approach can produce good compromise solutions corresponding to different decision-makers' preferences.

Quantifying site-specific physical heterogeneity within an estuarine seascape

USGS Publications Warehouse

Kennedy, Cristina G.; Mather, Martha E.; Smith, Joseph M.

2017-01-01

Quantifying physical heterogeneity is essential for meaningful ecological research and effective resource management. Spatial patterns of multiple, co-occurring physical features are rarely quantified across a seascape because of methodological challenges. Here, we identified approaches that measured total site-specific heterogeneity, an often overlooked aspect of estuarine ecosystems. Specifically, we examined 23 metrics that quantified four types of common physical features: (1) river and creek confluences, (2) bathymetric variation including underwater drop-offs, (3) land features such as islands/sandbars, and (4) major underwater channel networks. Our research at 40 sites throughout Plum Island Estuary (PIE) provided solutions to two problems. The first problem was that individual metrics that measured heterogeneity of a single physical feature showed different regional patterns. We solved this first problem by combining multiple metrics for a single feature using a within-physical feature cluster analysis. With this approach, we identified sites with four different types of confluences and three different types of underwater drop-offs. The second problem was that when multiple physical features co-occurred, new patterns of total site-specific heterogeneity were created across the seascape. This pattern of total heterogeneity has potential ecological relevance to structure-oriented predators. To address this second problem, we identified sites with similar types of total physical heterogeneity using an across-physical feature cluster analysis. Then, we calculated an additive heterogeneity index, which integrated all physical features at a site. Finally, we tested if site-specific additive heterogeneity index values differed for across-physical feature clusters. In PIE, the sites with the highest additive heterogeneity index values were clustered together and corresponded to sites where a fish predator, adult striped bass (Morone saxatilis), aggregated in a related acoustic tracking study. In summary, we have shown general approaches to quantifying site-specific heterogeneity.

EDITORIAL: Stability and nonlinear dynamics of plasmas: A symposium celebrating Professor Robert Dewar's accomplishments in plasma physics Stability and nonlinear dynamics of plasmas: A symposium celebrating Professor Robert Dewar's accomplishments in plasma physics

NASA Astrophysics Data System (ADS)

Bhattacharjee, Amitava

2012-01-01

To celebrate Professor Robert Dewar's 65th birthday, a Symposium was held on 31 October 2009 in Atlanta, Georgia, just before the 51st Annual Meeting of the Division of Plasma Physics of the American Physical Society. The Symposium was attended by many of Bob's colleagues, friends, postdoctoral colleagues and students (present and former). Boyd Blackwell, Anthony Cooper, Chris Hegna, Stuart Hudson, John Krommes, Alexander Pletzer, Ellen Zweibel, and I gave talks that covered various aspects of Bob's wide-ranging scholarship, and his leadership in the Australian and the US fusion program. At the Symposium, Bob gave an insightful talk, published in this issue as a paper with D Leykam. This paper makes available for the first time unpublished results from Bob's M Sc Thesis on a general method for calculating the potential around a `dressed' test particle in an isotropic and collisionless plasma. The paper is interesting not only because it provides a glimpse of the type of elegant applied mathematics that we have come to associate with Bob, but also because he discusses some leitmotifs in his intellectual evolution since the time he was a graduate student at the University of Melbourne and Princeton University. Through his early encounter with quantum field theory, Bob appreciated the power of Lagrangian and Hamiltonian formalisms, which he used with great effectiveness in nonlinear dynamics and plasma physics. A question that animates much of his work is one that underlies the `dressed' particle problem: if one is given a Hamiltonian with an unperturbed (or `bare') part and an interaction part, how is one to obtain a canonical transformation to `the oscillation centre' thatwould reduce the interaction part to an irreducible residual part while incorporating the rest in a renormalized zeroth-order Hamiltonian? One summer in Princeton, I worked with Bob on a possible variational formulation for this problem, and failed. I was daunted enough by my failure that I turned to MHD relaxation theory for my PhD thesis under Bob's supervision. It was a good decision because Bob showed me how beautiful MHD theory can be, but he did not himself give up the problem of formulating optimal oscillation-centre transformations. He has a singular ability to hold difficult problems like this in in his mind for many years until they crack open (or even if they do not!), a trait that many of us find altogether admirable. The impact of such thinking on plasma turbulence theory over the last four decades is described in the article by John Krommes in this issue. Stuart Hudson's article touches on some of the same themes in the pursuit of fully three-dimensional relaxed states in toroidal stellarators. Zensho Yoshida has contributed an interesting article on the interplay of Lagrangian and Eulerian representations of collective motions in a fluid, a theme that appears in Bob's work in several contexts. Underlying much of Bob's work on Hamiltonian systems is his deep knowledge and appreciation of Lie perturbation theory, and the article by Steven Richardson and John Finn, which discusses an example of symplectic integrators and their numerical implementation, reflects that interest. It is impossible to do justice to all of Bob's contributions to theoretical plasma physics in this short section. Bob's WKB theory of ballooning modes in three-dimensional toroidal systems (with Alan Glasser) is a classic paper that was in some ways years ahead of its time, especially in its exploration of the deep connections between KAM theory and the nature of the spectrum. In later work, he developed these ideas further by establishing connections with the phenomenon of Anderson localization in condensed matter physics. His papers on the subject of ballooning modes are gems of the plasma physics literature, and are unsurpassed in their mathematical elegance, insight, and their development of broad connections with other fields of theoretical physics. Some of this was covered in the talks at the Symposium. The paper by David Barmaz and coworkers published in this issue discusses the problem diamagnetic stabilization of ballooning instabilities in stellarators. It is not surprising that Bob's work on ballooning modes shows an accomplished master of WKB theory at work, for it is the culmination of a process that began many years earlier. His involvement in applications of WKB theory to problems involving instability and turbulence began in 1970, when he was a graduate student. At this time he wrote a very influential paper, discussed at the Symposium, on the interaction between hydromagnetic waves and a timedependent inhomogeneous medium. This paper is widely cited, especially in the astrophysical and space plasma literature, for it gives a rigorous method of evaluating the effects of lowfrequency hydromagnetic fluctuations on a slowly varying background medium. The method has found use in problems as diverse as the self-sustainment of molecular clouds, the heating and acceleration of the solar wind, and the effect of cosmic rays on the interplanetary medium. Attentive readers will note that Bob has been drafted as a co-author and participant in about half of the publications in this issue. This is a reflection of Bob's continued and tireless involvement in a wide spectrum of research problems that have their genesis in his fundamental contributions to plasma physics, as well as the eagerness with which we all welcome his involvement in our own projects. We hope to have this continue for many years to come.

Boundary conditions and transmission reflection of electron spin in a quantum well

NASA Astrophysics Data System (ADS)

Dargys, A.

2012-04-01

Boundary conditions for a spinor at the interface of hetero- and homobarrier in the presence of spin-orbit interaction are briefly reviewed and generalized. Then they are applied to 2D electron in the presence of a discontinuity of physical parameters in a quantum well. It is shown that in general case under oblique electron incidence, the problem can be solved analytically and the Fresnel-type formulae for polarization can be obtained if, in addition, the Gröbner basis algorithm is addressed to solve the problem. It is observed that the transmitted and reflected spin polarization may strongly depend on values of spin-orbit constants on both sides of the homobarrier in the quantum well.

Experience in using a numerical scheme with artificial viscosity at solving the Riemann problem for a multi-fluid model of multiphase flow

NASA Astrophysics Data System (ADS)

Bulovich, S. V.; Smirnov, E. M.

2018-05-01

The paper covers application of the artificial viscosity technique to numerical simulation of unsteady one-dimensional multiphase compressible flows on the base of the multi-fluid approach. The system of the governing equations is written under assumption of the pressure equilibrium between the "fluids" (phases). No interfacial exchange is taken into account. A model for evaluation of the artificial viscosity coefficient that (i) assumes identity of this coefficient for all interpenetrating phases and (ii) uses the multiphase-mixture Wood equation for evaluation of a scale speed of sound has been suggested. Performance of the artificial viscosity technique has been evaluated via numerical solution of a model problem of pressure discontinuity breakdown in a three-fluid medium. It has been shown that a relatively simple numerical scheme, explicit and first-order, combined with the suggested artificial viscosity model, predicts a physically correct behavior of the moving shock and expansion waves, and a subsequent refinement of the computational grid results in a monotonic approaching to an asymptotic time-dependent solution, without non-physical oscillations.

Overview of Aro Program on Network Science for Human Decision Making

NASA Astrophysics Data System (ADS)

West, Bruce J.

This program brings together researchers from disparate disciplines to work on a complex research problem that defies confinement within any single discipline. Consequently, not only are new and rewarding solutions sought and obtained for a problem of importance to society and the Army, that is, the human dimension of complex networks, but, in addition, collaborations are established that would not otherwise have formed given the traditional disciplinary compartmentalization of research. This program develops the basic research foundation of a science of networks supporting the linkage between the physical and human (cognitive and social) domains as they relate to human decision making. The strategy is to extend the recent methods of non-equilibrium statistical physics to non-stationary, renewal stochastic processes that appear to be characteristic of the interactions among nodes in complex networks. We also pursue understanding of the phenomenon of synchronization, whose mathematical formulation has recently provided insight into how complex networks reach accommodation and cooperation. The theoretical analyses of complex networks, although mathematically rigorous, often elude analytic solutions and require computer simulation and computation to analyze the underlying dynamic process.

Preface

NASA Astrophysics Data System (ADS)

Faybishenko, Boris; Witherspoon, Paul A.; Gale, John

How to characterize fluid flow, heat, and chemical transport in geologic media remains a central challenge for geoscientists and engineers worldwide. Investigations of fluid flow and transport within rock relate to such fundamental and applied problems as environmental remediation; nonaqueous phase liquid (NAPL) transport; exploitation of oil, gas, and geothermal resources; disposal of spent nuclear fuel; and geotechnical engineering. It is widely acknowledged that fractures in unsaturated-saturated rock can play a major role in solute transport from the land surface to underlying aquifers. It is also evident that general issues concerning flow and transport predictions in subsurface fractured zones can be resolved in a practical manner by integrating investigations into the physical nature of flow in fractures, developing relevant mathematical models and modeling approaches, and collecting site characterization data. Because of the complexity of flow and transport processes in most fractured rock flow problems, it is not yet possible to develop models directly from first principles. One reason for this is the presence of episodic, preferential water seepage and solute transport, which usually proceed more rapidly than expected from volume-averaged and time-averaged models. However, the physics of these processes is still known.

Comparing fluid mechanics models with experimental data.

PubMed Central

Spedding, G R

2003-01-01

The art of modelling the physical world lies in the appropriate simplification and abstraction of the complete problem. In fluid mechanics, the Navier-Stokes equations provide a model that is valid under most circumstances germane to animal locomotion, but the complexity of solutions provides strong incentive for the development of further, more simplified practical models. When the flow organizes itself so that all shearing motions are collected into localized patches, then various mathematical vortex models have been very successful in predicting and furthering the physical understanding of many flows, particularly in aerodynamics. Experimental models have the significant added convenience that the fluid mechanics can be generated by a real fluid, not a model, provided the appropriate dimensionless groups have similar values. Then, analogous problems can be encountered in making intelligible but independent descriptions of the experimental results. Finally, model predictions and experimental results may be compared if, and only if, numerical estimates of the likely variations in the tested quantities are provided. Examples from recent experimental measurements of wakes behind a fixed wing and behind a bird in free flight are used to illustrate these principles. PMID:14561348

A convex optimization method for self-organization in dynamic (FSO/RF) wireless networks

NASA Astrophysics Data System (ADS)

Llorca, Jaime; Davis, Christopher C.; Milner, Stuart D.

2008-08-01

Next generation communication networks are becoming increasingly complex systems. Previously, we presented a novel physics-based approach to model dynamic wireless networks as physical systems which react to local forces exerted on network nodes. We showed that under clear atmospheric conditions the network communication energy can be modeled as the potential energy of an analogous spring system and presented a distributed mobility control algorithm where nodes react to local forces driving the network to energy minimizing configurations. This paper extends our previous work by including the effects of atmospheric attenuation and transmitted power constraints in the optimization problem. We show how our new formulation still results in a convex energy minimization problem. Accordingly, an updated force-driven mobility control algorithm is presented. Forces on mobile backbone nodes are computed as the negative gradient of the new energy function. Results show how in the presence of atmospheric obscuration stronger forces are exerted on network nodes that make them move closer to each other, avoiding loss of connectivity. We show results in terms of network coverage and backbone connectivity and compare the developed algorithms for different scenarios.

Can phoretic particles swim in two dimensions?

NASA Astrophysics Data System (ADS)

Sondak, David; Hawley, Cory; Heng, Siyu; Vinsonhaler, Rebecca; Lauga, Eric; Thiffeault, Jean-Luc

2016-12-01

Artificial phoretic particles swim using self-generated gradients in chemical species (self-diffusiophoresis) or charges and currents (self-electrophoresis). These particles can be used to study the physics of collective motion in active matter and might have promising applications in bioengineering. In the case of self-diffusiophoresis, the classical physical model relies on a steady solution of the diffusion equation, from which chemical gradients, phoretic flows, and ultimately the swimming velocity may be derived. Motivated by disk-shaped particles in thin films and under confinement, we examine the extension to two dimensions. Because the two-dimensional diffusion equation lacks a steady state with the correct boundary conditions, Laplace transforms must be used to study the long-time behavior of the problem and determine the swimming velocity. For fixed chemical fluxes on the particle surface, we find that the swimming velocity ultimately always decays logarithmically in time. In the case of finite Péclet numbers, we solve the full advection-diffusion equation numerically and show that this decay can be avoided by the particle moving to regions of unconsumed reactant. Finite advection thus regularizes the two-dimensional phoretic problem.

CALL FOR PAPERS: Special issue on the random search problem: trends and perspectives

NASA Astrophysics Data System (ADS)

da Luz, Marcos G. E.; Grosberg, Alexander Y.; Raposo, Ernesto P.; Viswanathan, Gandhi M.

2008-11-01

This is a call for contributions to a special issue of Journal of Physics A: Mathematical and Theoretical dedicated to the subject of the random search problem. The motivation behind this special issue is to summarize in a single comprehensive publication, the main aspects (past and present), latest developments, different viewpoints and the directions being followed in this multidisciplinary field. We hope that such a special issue could become a particularly valuable reference for the broad scientific community working with the general random search problem. The Editorial Board has invited Marcos G E da Luz, Alexander Y Grosberg, Ernesto P Raposo and Gandhi M Viswanathan to serve as Guest Editors for the special issue. The general question of how to optimize the search for specific target objects in either continuous or discrete environments when the information available is limited is of significant importance in a broad range of fields. Representative examples include ecology (animal foraging, dispersion of populations), geology (oil recovery from mature reservoirs), information theory (automated researchers of registers in high-capacity database), molecular biology (proteins searching for their sites, e.g., on DNA ), etc. One reason underlying the richness of the random search problem relates to the `ignorance' of the locations of the randomly located `targets'. A statistical approach to the search problem can deal adequately with incomplete information and so stochastic strategies become advantageous. The general problem of how to search efficiently for randomly located target sites can thus be quantitatively described using the concepts and methods of statistical physics and stochastic processes. Scope Thus far, to the best of our knowledge, no recent textbook or review article in a physics journal has appeared on this topic. This makes a special issue with review and research articles attractive to those interested in acquiring a general introduction to the field. The subject can be approached from the perspective of different fields: ecology, networks, transport problems, molecular biology, etc. The study of the problem is particularly suited to the concepts and methods of statistical physics and stochastic processes; for example, fractals, random walks, anomalous diffusion. Discrete landscapes can be approached via graph theory, random lattices and complex networks. Such topics are regularly discussed in Journal of Physics A: Mathematical and Theoretical. All such aspects of the problem fall within the scope and focus of this special issue on the random search problem: trends and perspectives. Editorial policy All contributions to the special issue will be refereed in accordance with the refereeing policy of the journal. In particular, all research papers will be expected to be original work reporting substantial new results. The issue will also contain a number of review articles by invitation only. The Guest Editors reserve the right to judge whether a contribution fits the scope of the special issue. Guidelines for preparation of contributions We aim to publish the special issue in August 2009. To realize this, the DEADLINE for contributed papers is 15 January 2009. There is a page limit of 15 printed pages (approximately 9000 words) per contribution. For papers exceeding this limit, the Guest Editors reserve the right to request a reduction in length. Further advice on document preparation can be found at www.iop.org/Journals/jphysa. Contributions to the special issue should if possible be submitted electronically by web upload at www.iop.org/Journals/jphysa, or by email to jphysa@iop.org, quoting 'J. Phys. A Special Issue— Random Search Problem'. Please state whether the paper has been invited or is contributed. Submissions should ideally be in standard LaTeX form. Please see the website for further information on electronic submissions. Authors unable to submit electronically may send hard-copy contributions to: Publishing Administrators, Journal of Physics A, Institute of Physics Publishing, Dirac House, Temple Back, Bristol BS1 6BE, UK, enclosing electronic code on CD if available and quoting 'J. Phys. A Special Issue—Random Search Problem'. All contributions should be accompanied by a read-me file or covering letter giving the postal and e-mail addresses for correspondence. The Publishing Office should be notified of any subsequent change of address. This special issue will be published in the paper and online version of the journal. The corresponding author of each contribution will receive a complimentary copy of the issue.

The practice of problem-based investigative teaching reform in semiconductor physics course

NASA Astrophysics Data System (ADS)

Chen, Aiping; Wu, Gaojian; Gu, Dawei; Jiang, Hongying; Wang, Lei

2017-08-01

Semiconductor physics is an important basic course for the students of the majors of applied physics, optoelectronics, and microelectronics. The authors have been carrying out investigative-teaching reform in semiconductor physics teaching. Firstly, the teaching content was re-structured based on scientific problems. Secondly, the students were placed in groups to discuss different scientific problems and to present a few short science-reports. Thirdly, micro-lesson videos were produced for the students to study and analyze before or after class. With comparative analysis, we find out that the semiconductor-physics curriculum content was greatly enriched. In addition, the students' learning motivation and scientific thinking ability increased, and their innovation ability was improved. Overall, the teaching quality of the semiconductor physics course could be significantly improved.

Shedding light on El Farol

NASA Astrophysics Data System (ADS)

Challet, Damien; Marsili, M.; Ottino, Gabriele

2004-02-01

We mathematize El Farol bar problem and transform it into a workable model. We find general conditions on the predictor space under which the convergence of the average attendance to the resource level does not require any intelligence on the side of the agents. Secondly, specializing to a particular ensemble of continuous strategies yields a model similar to the Minority Game. Statistical physics of disordered systems allows us to derive a complete understanding of the complex behavior of this model, on the basis of its phase diagram.

Asymptotic-Preserving methods and multiscale models for plasma physics

NASA Astrophysics Data System (ADS)

Degond, Pierre; Deluzet, Fabrice

2017-05-01

The purpose of the present paper is to provide an overview of Asymptotic-Preserving methods for multiscale plasma simulations by addressing three singular perturbation problems. First, the quasi-neutral limit of fluid and kinetic models is investigated in the framework of non-magnetized as well as magnetized plasmas. Second, the drift limit for fluid descriptions of thermal plasmas under large magnetic fields is addressed. Finally efficient numerical resolutions of anisotropic elliptic or diffusion equations arising in magnetized plasma simulation are reviewed.

Non-Abelian Bosonization and Fractional Quantum Hall Transitions

NASA Astrophysics Data System (ADS)

Hui, Aaron; Mulligan, Michael; Kim, Eun-Ah

A fully satisfying theoretical description for the quantum phase transition between fractional quantum Hall plateaus remains an outstanding problem. Experiments indicate scaling exponents that are not readily obtained in conventional theories. Using insights from duality, we describe a class of quantum critical effective theories that produce qualitatively realistic scaling exponents for the transition. We discuss the implications of our results for the physically-relevant interactions controlling this broad class of quantum critical behavior. Supported by National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-1650441.

Improving Skilled Birth Attendance in Ghana: An Evidence-Based Policy Brief.

PubMed

Apanga, Paschal Awingura; Awoonor-Williams, John Koku

2017-01-01

This commentary has the objective of improving skilled birth attendance in Ghana to reduce maternal and neonatal mortality and morbidity. We have provided evidence of causes of low-skilled birth attendance in Ghana. Physical accessibility of health care, sociocultural factors, economic factors and health care system delivery problems were found as the main underlying causes of low levels of skilled birth attendance in Ghana. The paper provides potential strategies in addressing maternal and child health issues in Ghana.

Wigner Functions for Arbitrary Quantum Systems.

PubMed

Tilma, Todd; Everitt, Mark J; Samson, John H; Munro, William J; Nemoto, Kae

2016-10-28

The possibility of constructing a complete, continuous Wigner function for any quantum system has been a subject of investigation for over 50 years. A key system that has served to illustrate the difficulties of this problem has been an ensemble of spins. Here we present a general and consistent framework for constructing Wigner functions exploiting the underlying symmetries in the physical system at hand. The Wigner function can be used to fully describe any quantum system of arbitrary dimension or ensemble size.

Initial data sets and the topology of closed three-manifolds in general relativity

NASA Astrophysics Data System (ADS)

Carfora, M.

1983-10-01

The interaction between the matter content of a closed physical space associated with a generic gravitational configuration and the topology of the underlying closed three-manifold is discussed. Within the context of the conformal approach to the initial value problem, it is shown that the presence of enough matter and radiation favors the three-sphere topology or the worm-hole topology. It is argued that such topologies leave more room for possible gravitational initial data sets for the field equations.

Peptides that influence membrane topology

NASA Astrophysics Data System (ADS)

Wong, Gerard C. L.

2014-03-01

We examine the mechanism of a range of polypeptides that influence membrane topology, including antimicrobial peptides, cell penetrating peptides, viral fusion peptides, and apoptosis proteins, and show how a combination of geometry, coordination chemistry, and soft matter physics can be used to approach a unified understanding. We will also show how such peptides can impact biomedical problems such as auto-immune diseases (psoriasis, lupus), infectious diseases (viral and bacterial infections), and mitochondrial pathologies (under-regulated apoptosis leads to neurodegenerative diseases whereas over-regulated apoptosis leads to cancer.)

How to Chair Effective Meetings: A Guide to Group Problem Solving,

DTIC Science & Technology

1975-01-01

Physical Aids: 1. Felt-tip pens 2. Tablets 3. Pencils 4. Three-hole punch 5. Paper clips 6. Masking tape 7. Stapler 8. Water and glasses 9. Ash trays...basic ideas in the speaker’s own words - on large sheets of paper in full view of the group. The other group members have a responsibility under this...agenda handout or placed on chalkboard or paper pad) 2. Other handouts 3. Sign to identify meeting room 4. Name cards (tents) for participants, if needed

Testing posttraumatic stress as a mediator of physical, sexual, and psychological intimate partner violence and substance problems among women.

PubMed

Sullivan, Tami P; Cavanaugh, Courtenay E; Buckner, Julia D; Edmondson, Donald

2009-12-01

This study examined whether posttraumatic stress specifically resulting from intimate partner violence (IPV-related posttraumatic stress) mediated relationships between types of IPV and drug and alcohol problems among 212 women currently experiencing IPV. Six-month prevalence was high for drug use (48%) and alcohol use (59%). Structural equation modeling revealed that the frequency of physical, sexual, and psychological IPV were significantly and positively related to greater IPV-related posttraumatic stress, and IPV-related posttraumatic stress was significantly and positively related to drug problems. Further, IPV-related posttraumatic stress mediated the relationships between physical IPV and drug problems and psychological IPV and drug problems. Findings suggest that prevention and intervention efforts targeting posttraumatic stress among IPV-exposed women may reduce drug problems in this population.

3DGRAPE - THREE DIMENSIONAL GRIDS ABOUT ANYTHING BY POISSON'S EQUATION

NASA Technical Reports Server (NTRS)

Sorenson, R. L.

1994-01-01

The ability to treat arbitrary boundary shapes is one of the most desirable characteristics of a method for generating grids. 3DGRAPE is designed to make computational grids in or about almost any shape. These grids are generated by the solution of Poisson's differential equations in three dimensions. The program automatically finds its own values for inhomogeneous terms which give near-orthogonality and controlled grid cell height at boundaries. Grids generated by 3DGRAPE have been applied to both viscous and inviscid aerodynamic problems, and to problems in other fluid-dynamic areas. 3DGRAPE uses zones to solve the problem of warping one cube into the physical domain in real-world computational fluid dynamics problems. In a zonal approach, a physical domain is divided into regions, each of which maps into its own computational cube. It is believed that even the most complicated physical region can be divided into zones, and since it is possible to warp a cube into each zone, a grid generator which is oriented to zones and allows communication across zonal boundaries (where appropriate) solves the problem of topological complexity. 3DGRAPE expects to read in already-distributed x,y,z coordinates on the bodies of interest, coordinates which will remain fixed during the entire grid-generation process. The 3DGRAPE code makes no attempt to fit given body shapes and redistribute points thereon. Body-fitting is a formidable problem in itself. The user must either be working with some simple analytical body shape, upon which a simple analytical distribution can be easily effected, or must have available some sophisticated stand-alone body-fitting software. 3DGRAPE does not require the user to supply the block-to-block boundaries nor the shapes of the distribution of points. 3DGRAPE will typically supply those block-to-block boundaries simply as surfaces in the elliptic grid. Thus at block-to-block boundaries the following conditions are obtained: (1) grids lines will match up as they approach the block-to-block boundary from either side, (2) grid lines will cross the boundary with no slope discontinuity, (3) the spacing of points along the line piercing the boundary will be continuous, (4) the shape of the boundary will be consistent with the surrounding grid, and (5) the distribution of points on the boundary will be reasonable in view of the surrounding grid. 3DGRAPE offers a powerful building-block approach to complex 3-D grid generation, but is a low-level tool. Users may build each face of each block as they wish, from a wide variety of resources. 3DGRAPE uses point-successive-over-relaxation (point-SOR) to solve the Poisson equations. This method is slow, although it does vectorize nicely. Any number of sophisticated graphics programs may be used on the stored output file of 3DGRAPE though it lacks interactive graphics. Versatility was a prominent consideration in developing the code. The block structure allows a great latitude in the problems it can treat. As the acronym implies, this program should be able to handle just about any physical region into which a computational cube or cubes can be warped. 3DGRAPE was written in FORTRAN 77 and should be machine independent. It was originally developed on a Cray under COS and tested on a MicroVAX 3200 under VMS 5.1.

Multiple representations and free-body diagrams: Do students benefit from using them?

NASA Astrophysics Data System (ADS)

Rosengrant, David R.

2007-12-01

Introductory physics students have difficulties understanding concepts and solving problems. When they solve problems, they use surface features of the problems to find an equation to calculate a numerical answer often not understanding the physics in the problem. How do we help students approach problem solving in an expert manner? A possible answer is to help them learn to represent knowledge in multiple ways and then use these different representations for conceptual understanding and problem solving. This solution follows from research in cognitive science and in physics education. However, there are no studies in physics that investigate whether students who learn to use multiple representations are in fact better problem solvers. This study focuses on one specific representation used in physics--a free body diagram. A free-body diagram is a graphical representation of forces exerted on an object of interest by other objects. I used the free-body diagram to investigate five main questions: (1) If students are in a course where they consistently use free body diagrams to construct and test concepts in mechanics, electricity and magnetism and to solve problems in class and in homework, will they draw free-body diagrams on their own when solving exam problems? (2) Are students who use free-body diagrams to solve problems more successful then those who do not? (3) Why do students draw free-body diagrams when solving problems? (4) Are students consistent in constructing diagrams for different concepts in physics and are they consistent in the quality of their diagrams? (5) What are possible relationships between features of a problem and how likely a student will draw a free body diagram to help them solve the problem? I utilized a mixed-methods approach to answer these questions. Questions 1, 2, 4 and 5 required a quantitative approach while question 3 required a qualitative approach, a case study. When I completed my study, I found that if students are in an environment which fosters the use of representations for problem solving and for concept development, then the majority of students will consistently construct helpful free-body diagrams and use them on their own to solve problems. Additionally, those that construct correct free-body diagrams are significantly more likely to successfully solve the problem. Finally, those students that are high achieving tend to use diagrams more and for more reasons then students who have low course grades. These findings will have major impacts on how introductory physics instructors run their classes and how curriculums are designed. These results favor a problem solving strategy that is rich with representations.

Role of multiple representations in physics problem solving

NASA Astrophysics Data System (ADS)

Maries, Alexandru

This thesis explores the role of multiple representations in introductory physics students' problem solving performance through several investigations. Representations can help students focus on the conceptual aspects of physics and play a major role in effective problem solving. Diagrammatic representations can play a particularly important role in the initial stages of conceptual analysis and planning of the problem solution. Findings suggest that students who draw productive diagrams are more successful problem solvers even if their approach is primarily mathematical. Furthermore, students provided with a diagram of the physical situation presented in a problem sometimes exhibited deteriorated performance. Think-aloud interviews suggest that this deteriorated performance is in part due to reduced conceptual planning time which caused students to jump to the implementation stage without fully understanding the problem and planning problem solution. Another study investigated two interventions aimed at improving introductory students' representational consistency between mathematical and graphical representations and revealed that excessive scaffolding can have a detrimental effect. The detrimental effect was partly due to increased cognitive load brought on by the additional steps and instructions. Moreover, students who exhibited representational consistency also showed improved problem solving performance. The final investigation is centered on a problem solving task designed to provide information about the pedagogical content knowledge (PCK) of graduate student teaching assistants (TAs). In particular, the TAs identified what they considered to be the most common difficulties of introductory physics students related to graphical representations of kinematics concepts as they occur in the Test of Understanding Graphs in Kinematics (TUG-K). As an extension, the Force Concept Inventory (FCI) was also used to assess this aspect of PCK related to knowledge of student difficulties of both physics instructors and TAs. We find that teaching an independent course and recent teaching experience do not correlate with improved PCK. In addition, the performance of American TAs, Chinese TAs and other foreign TAs in identifying common student difficulties both in the context of the TUG-K and in the context of the FCI is similar. Moreover, there were many common difficulties of introductory physics students that were not identified by many instructors and TAs.

To draw or not to draw? Examining the necessity of problem diagrams using massive open online course experiments

NASA Astrophysics Data System (ADS)

Chen, Zhongzhou; Demirci, Neset; Choi, Youn-Jeng; Pritchard, David E.

2017-06-01

Previous research on problem diagrams suggested that including a supportive diagram, one that does not provide necessary problem solving information, may bring little, or even negative, benefit to students' problem solving success. We tested the usefulness of problem diagrams on 12 different physics problems (6A/B experiments) in our massive open online course. By analyzing over 8000 student responses in total, we found that including a problem diagram that contains no significant additional information only slightly improves the first attempt correct rate for the few most spatially complex problems, and has little impact on either the final correct percentage or the time spent on solving the problem. On the other hand, in half of the cases, removing the diagram significantly increased the fraction of students' drawing their own diagrams during problem solving. The increase in drawing behavior is largely independent of students' physics abilities. In summary, our results suggest that for many physics problems, the benefit of a diagram is exceedingly small and may not justify the effort of creating one.

Association between Psychopathology and Physical Health Problems among Youth in Residential Treatment

ERIC Educational Resources Information Center

Nelson, Timothy D.; Smith, Tori R.; Duppong Hurley, Kristin; Epstein, Michael H.; Thompson, Ronald W.; Tonniges, Thomas F.

2013-01-01

Youth in residential treatment settings often present with a complex combination of mental and physical health problems. Despite an emerging literature documenting significant associations between mental health and physical health, the relationship between these two areas of functioning has not been systematically examined in youth presenting to…

Online with Integers

ERIC Educational Resources Information Center

Siegel, Jonathan W.; Siegel, P. B.

2011-01-01

Integers are sometimes used in physics problems to simplify the mathematics so the arithmetic does not distract students from the physics concepts. This is particularly important in exams where students should not have to spend a lot of time using their calculators. Common uses of integers in physics problems include integer solutions to…

Including Critical Thinking and Problem Solving in Physical Education

ERIC Educational Resources Information Center

Pill, Shane; SueSee, Brendan

2017-01-01

Many physical education curriculum frameworks include statements about the inclusion of critical inquiry processes and the development of creativity and problem-solving skills. The learning environment created by physical education can encourage or limit the application and development of the learners' cognitive resources for critical and creative…

More than Just "Plug-and-Chug": Exploring How Physics Students Make Sense with Equations

ERIC Educational Resources Information Center

Kuo, Eric

2013-01-01

Although a large part the Physics Education Research (PER) literature investigates students' conceptual understanding in physics, these investigations focus on qualitative, conceptual reasoning. Even in modeling expert problem solving, attention to conceptual understanding means a focus on initial qualitative analysis of the problem; the equations…

Dissociative Conceptual and Quantitative Problem Solving Outcomes across Interactive Engagement and Traditional Format Introductory Physics

ERIC Educational Resources Information Center

McDaniel, Mark A.; Stoen, Siera M.; Frey, Regina F.; Markow, Zachary E.; Hynes, K. Mairin; Zhao, Jiuqing; Cahill, Michael J.

2016-01-01

The existing literature indicates that interactive-engagement (IE) based general physics classes improve conceptual learning relative to more traditional lecture-oriented classrooms. Very little research, however, has examined quantitative problem-solving outcomes from IE based relative to traditional lecture-based physics classes. The present…

Physical Symptoms and Psychological Distress among Inhalant Users.

ERIC Educational Resources Information Center

Joe, George W.; And Others

1991-01-01

Among 110 Mexican-American adolescents with varying drug use histories, self-reported physical health problems were not related to inhalant use history, but blood analyses indicated a relationship between extensive inhalant use and liver problems. Psychological distress symptoms were related to inhalant use and physical symptoms. Contains 23…

Modelling Mathematical Reasoning in Physics Education

ERIC Educational Resources Information Center

Uhden, Olaf; Karam, Ricardo; Pietrocola, Mauricio; Pospiech, Gesche

2012-01-01

Many findings from research as well as reports from teachers describe students' problem solving strategies as manipulation of formulas by rote. The resulting dissatisfaction with quantitative physical textbook problems seems to influence the attitude towards the role of mathematics in physics education in general. Mathematics is often seen as a…