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Sample records for early diffractive physics

  1. QCD subgroup on diffractive and forward physics

    SciTech Connect

    Albrow, M.G.; Baker, W.; Bhatti, A.

    1997-09-01

    Over the last few years, there has been a resurgence of interest in small-x or diffractive physics. This has been due to the realization that perturbative QCD techniques may be applicable to what was previously thought of as a non-perturbative problem and to the opening up of new energy regimes at HERA and the Tevatron collider. The goal is to understand the pomeron, and hence the behavior of total cross sections, elastic scattering and diffractive excitation, in terms of the underlying theory, QCD. This paper is divided into experiments of hadron-hadron colliders and electron-proton colliders.

  2. New Forward and Diffractive Physics at CMS

    NASA Astrophysics Data System (ADS)

    Santoro, Alberto

    2011-04-01

    Forward and Diffractive Physics (FWP) in LHC is a new open window to understand this type of strong interactions. We will present a didactic description of the topics being developed at CMS. As we know there still is no new results to present for FWP. We are accumulating data to have soon new results. We will show a number of topics and the detectors properties to do the observation of several topologies. We expect to give an optimistic view of the area.

  3. Soft QCD and Diffractive Physics at Lhc

    NASA Astrophysics Data System (ADS)

    Scapparone, Eugenio

    2012-12-01

    After a short introduction on the importance of the soft and of the diffractive studies in the understanding of minimum bias events, the main results obtained at LHC are discussed. This overview includes identified particle and inclusive measurements, minimum bias and underlying events, all of them shedding light on the soft process production mechanisms. The results of the inelastic cross-section measurements obtained by the LHC experiments and their compatibility are discussed together with the models used to extrapolate the data at low diffractive masses. A review of the most recent diffraction results is presented, showing the different approaches used by the LHC experiments, relying on different experimental techniques. The combination of the results obtained by ALICE, ATLAS, CMS, LHCb and TOTEM provides a wide sample of informations, covering an unprecedented pseudorapidity range. A detailed comparison between the obtained results is shown, followed by a critical discussion on the still existing discrepancies between the experimental data and the Monte Carlo used at LHC to simulate soft and diffractive physics.

  4. Physical Education in Early Childhood

    ERIC Educational Resources Information Center

    Stork, Steve; Sanders, Stephen W.

    2008-01-01

    This article examines the incidence and quality of physical activity instruction during early childhood. Although the positive effect of physical activity on the cognitive, social, and physical development of young children is generally acknowledged, there is little emphasis nationally on ensuring appropriate physical educational experiences…

  5. Diffraction and Forward Physics in ATLAS: results and perspectives

    NASA Astrophysics Data System (ADS)

    Bruschi, M.

    2015-03-01

    The present and future potential of ATLAS for diffraction and forward physics is presented. As recent results the rapidity gap cross section and elastic and total pp cross sections are reported. The upgrade project AFP is presented and it is shown how it will complement the ALFA acceptance for diffractive physics in measurements taken with β*=90 m LHC beam optics. Moreover, the AFP detector will guarantee good acceptance on diffractive events also during normal running conditions allowing to improve the ATLAS detector performances. If in addition, a high luminosity program will be feasible, AFP might be fundamental for potential discoveries with extra dimensions being one example.

  6. Physics issues in diffraction limited storage ring design

    NASA Astrophysics Data System (ADS)

    Fan, Wei; Bai, ZhengHe; Gao, WeiWei; Feng, GuangYao; Li, WeiMin; Wang, Lin; He, DuoHui

    2012-05-01

    Diffraction limited electron storage ring is considered a promising candidate for future light sources, whose main characteristics are higher brilliance, better transverse coherence and better stability. The challenge of diffraction limited storage ring design is how to achieve the ultra low beam emittance with acceptable nonlinear performance. Effective linear and nonlinear parameter optimization methods based on Artificial Intelligence were developed for the storage ring physical design. As an example of application, partial physical design of HALS (Hefei Advanced Light Source), which is a diffraction limited VUV and soft X-ray light source, was introduced. Severe emittance growth due to the Intra Beam Scattering effect, which is the main obstacle to achieve ultra low emittance, was estimated quantitatively and possible cures were discussed. It is inspiring that better performance of diffraction limited storage ring can be achieved in principle with careful parameter optimization.

  7. Recent forward physics and diffraction results from CMS

    NASA Astrophysics Data System (ADS)

    Veres, Gábor

    2016-07-01

    Recent CMS results on forward physics and diffraction are reviewed. The differential diffractive cross section is measured as a function of ξ = M2X/S in the region dominated by single dissociation (SD) and double dissociation (DD), where MX is the mass of one of the two final-state hadronic systems separated by the largest rapidity gap in the event. The total SD and DD cross sections are extracted. The observation of a hard color-singlet exchange process in events with a large rapidity gap between two leading jets (jet-gap-jet) is reported. The fraction of jet-gap-jet to all dijet events is measured as a function of the second leading jet transverse momentum and the size of the pseudorapidity gap. The measured fractions are compared with predictions as well as Tevatron data.

  8. Diffractive Physics at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Revol, Jean-Pierre

    2011-07-01

    After a short introduction on diffraction, I briefly review the framework used to describe non-perturbative QCD phenomena in hadron-hadron interactions. Then I explain why diffractive processes cannot be ignored at LHC and how ALICE, ATLAS, CMS, LHCb and TOTEM study diffraction, with emphasis on how inclusive particle production measurements are normalised to non-single diffractive and inelastic event classes.

  9. Physical Science in Constructivist Early Childhood Classrooms

    ERIC Educational Resources Information Center

    Kato, Tsuguhiko; Van Meeteren, Beth Dykstra

    2008-01-01

    Teachers at the Freeburg Early Childhood Program know that experimentation with physical science is of great interest to young children, and can begin as early as the age of 3. The constructivist teachers at this experimental school at the University of Northern Iowa worked for six years to develop a center-based approach to physical science with…

  10. Physical Fitness and the Early Childhood Curriculum

    ERIC Educational Resources Information Center

    Pica, Rae

    2006-01-01

    The state of children's fitness is the responsibility of all who are involved with children. As early childhood professionals, they have a duty to educate the whole (thinking, feeling, "moving") child. Moreover, teachers of preschoolers can be more realistic than parents in their assessment of children's physical inactivity levels, and preschool…

  11. Quantum Optics, Diffraction Theory, and Elementary Particle Physics

    ScienceCinema

    None

    2011-10-06

    Physical optics has expanded greatly in recent years. Though it remains part of the ancestry of elementary particle physics, there are once again lessons to be learned from it. I shall discuss several of these, including some that have emerged at CERN and Brookhaven.

  12. Forward shower counters for diffractive physics at the LHC

    NASA Astrophysics Data System (ADS)

    Albrow, Michael; Collins, Paula; Penzo, Aldo

    2014-11-01

    The LHC detectors have incomplete angular coverage in the forward direction, for example in the region 6 ≲ |η| ≲ 8, which can be improved with the addition of simple scintillation counters around the beam pipes about 50 m to 120 m from the intersection point. These counters detect showers created by particles hitting the beam pipes and nearby material. The absence of signals in these counters in low pileup conditions is an indication of a forward rapidity gap as a signature of diffraction. In addition, they can be used to detect hadrons from low mass diffractive excitations of the proton, not accompanied by a leading proton but adjacent to a rapidity gap over (e.g.) 3 ≲ |η| ≲ 6. Such a set of forward shower counters, originally used at CDF, was used in CMS (FSC) for high-β* running with TOTEM during LHC Run-1. During LS1 the CMS FSC system is being upgraded for future low pileup runs. A similar system, called HERSCHEL is being installed in LHCb. ALICE is implementing scintillation counters, ADA and ADC, with 4.5 ≲ |η| ≲ 6.4.

  13. Particle physics in the very early universe

    NASA Technical Reports Server (NTRS)

    Schramm, D. N.

    1981-01-01

    Events in the very early big bang universe in which elementary particle physics effects may have been dominant are discussed, with attention to the generation of a net baryon number by way of grand unification theory, and emphasis on the possible role of massive neutrinos in increasing current understanding of various cosmological properties and of the constraints placed on neutrino properties by cosmology. It is noted that when grand unification theories are used to describe very early universe interactions, an initially baryon-symmetrical universe can evolve a net baryon excess of 10 to the -9th to 10 to the -11th per photon, given reasonable parameters. If neutrinos have mass, the bulk of the mass of the universe may be in the form of leptons, implying that the form of matter most familiar to physical science may not be the dominant form of matter in the universe.

  14. Early Spacelab physics and astronomy missions

    NASA Technical Reports Server (NTRS)

    Chapman, R. D.

    1976-01-01

    Some of the scientific problems which will be investigated during the early Spacelab physics and astronomy missions are reviewed. The Solar Terrestrial Programs will include the Solar Physics Spacelab Payloads (SPSP) and the Atmospheres, Magnetospheres and Plasmas in Space (AMPS) missions. These missions will study the sun as a star and the influence of solar phenomena on the earth, including sun-solar wind interface, the nature of the solar flares, etc. The Astrophysics Spacelab Payloads (ASP) programs are divided into the Ultraviolet-Optical Astronomy and the High Energy Astrophysics areas. The themes of astrophysics Spacelab investigations will cover the nature of the universe, the fate of matter and the life cycles of stars. The paper discusses various scientific experiments and instruments to be used in the early Spacelab missions.

  15. The early development of neutron diffraction: science in the wings of the Manhattan Project

    SciTech Connect

    Mason, T. E. Gawne, T. J.; Nagler, S. E.; Nestor, M. B.; Carpenter, J. M.

    2013-01-01

    Early neutron diffraction experiments performed in 1944 using the first nuclear reactors are described. Although neutron diffraction was first observed using radioactive decay sources shortly after the discovery of the neutron, it was only with the availability of higher intensity neutron beams from the first nuclear reactors, constructed as part of the Manhattan Project, that systematic investigation of Bragg scattering became possible. Remarkably, at a time when the war effort was singularly focused on the development of the atomic bomb, groups working at Oak Ridge and Chicago carried out key measurements and recognized the future utility of neutron diffraction quite independent of its contributions to the measurement of nuclear cross sections. Ernest O. Wollan, Lyle B. Borst and Walter H. Zinn were all able to observe neutron diffraction in 1944 using the X-10 graphite reactor and the CP-3 heavy water reactor. Subsequent work by Wollan and Clifford G. Shull, who joined Wollan’s group at Oak Ridge in 1946, laid the foundations for widespread application of neutron diffraction as an important research tool.

  16. Spin and diffractive physics with a fixed-target experiment at the LHC (AFTER-LHC)

    SciTech Connect

    Lorce, C.; Chambert, V.; Didelez, J. P.; Genolini, B.; Hadjidakis, C.; Lansberg, J. P.; Rosier, P.; Brodsky, S. J.; Ferreiro, E. G.; Fleuret, F.

    2013-04-15

    We report on the spin and diffractive physics at a future multi-purpose f xed-target experiment with proton and lead LHC beams extracted by a bent crystal. The LHC multi-TeV beams allow for the most energetic f xed-target experiments ever performed, opening new domains of particle and nuclear physics and complementing that of collider physics, in particular that of RHIC and the EIC projects. The luminosity achievable with AFTER using typical targets would surpass that of RHIC by more than 3 orders of magnitude. The f xed-target mode has the advantage to allow for measurements of single-spin asymmetries with polarized target as well as of single-diffractive processes in the target region.

  17. Uniform diffracted fields from a perfectly conducting cylindrical reflector with modified theory of physical optics.

    PubMed

    Yalçın, Uğur; Sarnık, Mücahit

    2013-01-01

    The uniform diffracted fields are calculated on PEC cylindrical reflector by Modified Theory of Physical Optics (MTPO). It is aimed to convert the noncontinuous solution to a continuous solution by finding a uniform equation which does not contain any expression converging to 0 in the denominator part. Three axioms of MTPO theory are used to construct the integral equations for the perfectly electrically conducting surface application. The "edge-point" technique is used to find the diffracted field, and uniform solution is to be found via "detour parameter(s)." Finally, the obtained results are to be compared with the nonuniform ones, numerically. PMID:23766679

  18. A system model for ultrasonic NDT based on the Physical Theory of Diffraction (PTD).

    PubMed

    Darmon, M; Dorval, V; Kamta Djakou, A; Fradkin, L; Chatillon, S

    2016-01-01

    Simulation of ultrasonic Non Destructive Testing (NDT) is helpful for evaluating performances of inspection techniques and requires the modelling of waves scattered by defects. Two classical flaw scattering models have been previously usually employed and evaluated to deal with inspection of planar defects, the Kirchhoff approximation (KA) for simulating reflection and the Geometrical Theory of Diffraction (GTD) for simulating diffraction. Combining them so as to retain advantages of both, the Physical Theory of Diffraction (PTD) initially developed in electromagnetism has been recently extended to elastodynamics. In this paper a PTD-based system model is proposed for simulating the ultrasonic response of crack-like defects. It is also extended to provide good description of regions surrounding critical rays where the shear diffracted waves and head waves interfere. Both numerical and experimental validation of the PTD model is carried out in various practical NDT configurations, such as pulse echo and Time of Flight Diffraction (TOFD), involving both crack tip and corner echoes. Numerical validation involves comparison of this model with KA and GTD as well as the Finite-Element Method (FEM). PMID:26323548

  19. Diffracted and pseudo-physical waves from spatially limited arrays using source-receiver interferometry (SRI)

    NASA Astrophysics Data System (ADS)

    Löer, Katrin; Meles, Giovanni Angelo; Curtis, Andrew; Vasconcelos, Ivan

    2014-02-01

    Source-receiver interferometry (SRI) refers to a technique to construct the Green's function between a source and a receiver using only energy that has travelled from and to surrounding boundaries of sources and receivers. If a background medium is perturbed, the corresponding interferometric equation can be expressed as the sum of eight terms, which result from the separation of the total wavefield into an unperturbed background field and the perturbed scattered field. Here, the contribution of each individual term is identified for singly diffracted waves using the methods of stationary phase analysis and waveform modelling. When the data acquisition boundary requirements for seismic interferometry are violated, non-physical energy is introduced into Green's function estimates. Our results show that four terms produce purely non-physical, non-stationary energy and that these can be suppressed, and that a combination of only two terms can be used to estimate diffracted wavefields robustly. One of the two terms is precisely that used in geophysical imaging schemes. A key result is that this term also produces non-physical energy, except when the integration boundaries are truncated to span only part of the medium's free surface: we thus show that in this sense, partial boundaries can be seen as a positive advantage for migration or imaging methods. The other term produces non-physical energy which nevertheless emulates physical energy; such energy is therefore called pseudo-physical. We present for the first time a complete mathematical derivation of this new category of energy complemented with illustrative examples. Overall, this work significantly enhances our understanding of how scattered wave SRI works.

  20. Promoting Physical Activity during Early Childhood

    ERIC Educational Resources Information Center

    Vidoni, Carla; Ignico, Arlene

    2011-01-01

    The prevalence of obesity in children and adolescents from low-income families in the USA has become a significant concern over the last 20 years. One of the major contributors to this problem is the lack of physical activity. The purpose of this paper is to describe initiatives designed to: (1) engage young children in physical activity during…

  1. Early Childhood Services: Physical Resources Guide.

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton.

    Introduced by a parable on the value of children's play, this guidebook includes a list of 10 developmental functions of play, a discussion of matters for consideration in selecting and organizing equipment and facilities for early childhood programs, and a description of indoor and outdoor program resources for children's activities. Various…

  2. A study of swing-curve physics in diffraction-based overlay

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Kaustuve; den Boef, Arie; Storms, Greet; van Heijst, Joost; Noot, Marc; An, Kevin; Park, Noh-Kyoung; Jeon, Se-Ra; Oh, Nang-Lyeom; McNamara, Elliott; van de Mast, Frank; Oh, SeungHwa; Lee, Seung Yoon; Hwang, Chan; Lee, Kuntack

    2016-03-01

    With the increase of process complexity in advanced nodes, the requirements of process robustness in overlay metrology continues to tighten. Especially with the introduction of newer materials in the film-stack along with typical stack variations (thickness, optical properties, profile asymmetry etc.), the signal formation physics in diffraction-based overlay (DBO) becomes an important aspect to apply in overlay metrology target and recipe selection. In order to address the signal formation physics, an effort is made towards studying the swing-curve phenomena through wavelength and polarizations on production stacks using simulations as well as experimental technique using DBO. The results provide a wealth of information on target and recipe selection for robustness. Details from simulation and measurements will be reported in this technical publication.

  3. Physical conditions on the early Earth.

    PubMed

    Lunine, Jonathan I

    2006-10-29

    The formation of the Earth as a planet was a large stochastic process in which the rapid assembly of asteroidal-to-Mars-sized bodies was followed by a more extended period of growth through collisions of these objects, facilitated by the gravitational perturbations associated with Jupiter. The Earth's inventory of water and organic molecules may have come from diverse sources, not more than 10% roughly from comets, the rest from asteroidal precursors to chondritic bodies and possibly objects near Earth's orbit for which no representative class of meteorites exists today in laboratory collections. The final assembly of the Earth included a catastrophic impact with a Mars-sized body, ejecting mantle and crustal material to form the Moon, and also devolatilizing part of the Earth. A magma ocean and steam atmosphere (possibly with silica vapour) existed briefly in this period, but terrestrial surface waters were below the critical point within 100 million years after Earth's formation, and liquid water existed continuously on the surface within a few hundred million years. Organic material delivered by comets and asteroids would have survived, in part, this violent early period, but frequent impacts of remaining debris probably prevented the continuous habitability of the Earth for one to several hundred million years. Planetary analogues to or records of this early time when life began include Io (heat flow), Titan (organic chemistry) and Venus (remnant early granites). PMID:17008213

  4. Physical conditions on the early Earth

    PubMed Central

    Lunine, Jonathan I

    2006-01-01

    The formation of the Earth as a planet was a large stochastic process in which the rapid assembly of asteroidal-to-Mars-sized bodies was followed by a more extended period of growth through collisions of these objects, facilitated by the gravitational perturbations associated with Jupiter. The Earth's inventory of water and organic molecules may have come from diverse sources, not more than 10% roughly from comets, the rest from asteroidal precursors to chondritic bodies and possibly objects near Earth's orbit for which no representative class of meteorites exists today in laboratory collections. The final assembly of the Earth included a catastrophic impact with a Mars-sized body, ejecting mantle and crustal material to form the Moon, and also devolatilizing part of the Earth. A magma ocean and steam atmosphere (possibly with silica vapour) existed briefly in this period, but terrestrial surface waters were below the critical point within 100 million years after Earth's formation, and liquid water existed continuously on the surface within a few hundred million years. Organic material delivered by comets and asteroids would have survived, in part, this violent early period, but frequent impacts of remaining debris probably prevented the continuous habitability of the Earth for one to several hundred million years. Planetary analogues to or records of this early time when life began include Io (heat flow), Titan (organic chemistry) and Venus (remnant early granites). PMID:17008213

  5. Early physics and astronomy. A historical introduction.

    NASA Astrophysics Data System (ADS)

    Pedersen, O.

    This book (first published in 1974) is an introductory exposition of the development of the physical and astronomical notions of the universe. It covers the period from Greek Antiquity to the Copernican revolution and the Renaissance, half of the text being devoted to Mediaeval Science within both the Aristotelian and the Archimedean traditions. It has a extensive bibliography classifying much of the secondary literature on the subject, and also a sixty page dictionary of all the scientists and philosophers mentioned in the text.

  6. In-situ early-age hydration study of sulfobelite cements by synchrotron powder diffraction

    SciTech Connect

    Álvarez-Pinazo, G.; Cuesta, A.; García-Maté, M.; Santacruz, I.; Losilla, E.R.; Fauth, F.; Aranda, M.A.G.; De la Torre, A.G.

    2014-02-15

    Eco-friendly belite calcium sulfoaluminate (BCSA) cement hydration behavior is not yet well understood. Here, we report an in-situ synchrotron X-ray powder diffraction study for the first hours of hydration of BCSA cements. Rietveld quantitative phase analysis has been used to establish the degree of reaction (α). The hydration of a mixture of ye'elimite and gypsum revealed that ettringite formation (α ∼ 70% at 50 h) is limited by ye'elimite dissolution. Two laboratory-prepared BCSA cements were also studied: non-active-BCSA and active-BCSA cements, with β- and α′{sub H}-belite as main phases, respectively. Ye'elimite, in the non-active-BCSA system, dissolves at higher pace (α ∼ 25% at 1 h) than in the active-BCSA one (α ∼ 10% at 1 h), with differences in the crystallization of ettringite (α ∼ 30% and α ∼ 5%, respectively). This behavior has strongly affected subsequent belite and ferrite reactivities, yielding stratlingite and other layered phases in non-active-BCSA. The dissolution and crystallization processes are reported and discussed in detail. -- Highlights: •Belite calcium sulfoaluminate cements early hydration mechanism has been determined. •Belite hydration strongly depends on availability of aluminum hydroxide. •Orthorhombic ye’elimite dissolved at a higher pace than cubic one. •Ye’elimite larger reaction degree yields stratlingite formation by belite reaction. •Rietveld method quantified gypsum, anhydrite and bassanite dissolution rates.

  7. Early Childhood Educators' Experience of an Alternative Physical Education Model

    ERIC Educational Resources Information Center

    Tsangaridou, Niki; Genethliou, Nicholas

    2016-01-01

    Alternative instructional and curricular models are regarded as more comprehensive and suitable approaches to providing quality physical education (Kulinna 2008; Lund and Tannehill 2010; McKenzie and Kahan 2008; Metzler 2011; Quay and Peters 2008). The purpose of this study was to describe the impact of the Early Steps Physical Education…

  8. Physical Identification of Binary System of Gliclazide-Hydrophilic Polymers Using X-Ray Diffraction

    NASA Astrophysics Data System (ADS)

    Rachmawati, H.; Yatinasari, Faizatun, Syarie, S. A.

    2008-03-01

    The formation of binary system in pharmaceutical solid state is aimed to improve the physicochemical characteristics of active compound, such as its solubility. To identify the physical change of the binary system including crystallinity or particle morphology, there are many methods can be applied. In present report, we study the physical interaction of the binary system of gliclazide and hydrophilic polymers. In this binary system, gliclazide was either dispersed or mixed with polyvinyl pirrolidone (PVP K30) or polyethylene glycol (PEG 6000). The dispersion system of gliclazide in the polymeric carriers was prepared by solvation-evaporation method, using dichloromethane/methylene chloride as an organic solvent. The physical characterization of both dispersed and mixed of gliclazide was studied using X-ray diffraction at interval 6-50 °/2θ. As a comparison, the same procedure was performed for pure gliclazide. To confirm the diffractogram of this binary system, Fourier Transform Infrared (FT-IR) spectroscopy was carried out as well. Both diffarctogram and FT-IR spectra revealed that there was no new compound formed in the solid dispersion system of gliclazide:PEG 6000 and gliclazide:PVP K30. In contrast, the solubility as well as the dissolution rate of gliclazide in the presence of both hydrophilic polymers was increased as compared to pure gliclazide. We conclude therefore that solvatation followed by evaporation of gliclazide in the presence of either PEG 6000 or PVP K30 did not alter its crystalline characteristic. The improved of gliclazide solubility in the binary system might due to other mechanism such as increased in the wettability and the hydrophylicity effect of the polymers.

  9. The early development of neutron diffraction: science in the wings of the Manhattan Project.

    PubMed

    Mason, T E; Gawne, T J; Nagler, S E; Nestor, M B; Carpenter, J M

    2013-01-01

    Although neutron diffraction was first observed using radioactive decay sources shortly after the discovery of the neutron, it was only with the availability of higher intensity neutron beams from the first nuclear reactors, constructed as part of the Manhattan Project, that systematic investigation of Bragg scattering became possible. Remarkably, at a time when the war effort was singularly focused on the development of the atomic bomb, groups working at Oak Ridge and Chicago carried out key measurements and recognized the future utility of neutron diffraction quite independent of its contributions to the measurement of nuclear cross sections. Ernest O. Wollan, Lyle B. Borst and Walter H. Zinn were all able to observe neutron diffraction in 1944 using the X-10 graphite reactor and the CP-3 heavy water reactor. Subsequent work by Wollan and Clifford G. Shull, who joined Wollan's group at Oak Ridge in 1946, laid the foundations for widespread application of neutron diffraction as an important research tool. PMID:23250059

  10. Service Delivery Complexities: Early Intervention for Children with Physical Disabilities

    ERIC Educational Resources Information Center

    Ziviani, Jenny; Darlington, Yvonne; Feeney, Rachel; Rodger, Sylvia; Watter, Pauline

    2013-01-01

    Early intervention (EI) for children with physical disabilities is advocated as a means of enhancing child outcomes and family functioning. The issues confronted by service providers in delivering this support have received relatively little attention. The purpose of this study was to gain an understanding of the experiences of frontline EI staff…

  11. Discontinuities in Early Development of the Understanding of Physical Causality

    ERIC Educational Resources Information Center

    Aschersleben, Gisa; Henning, Anne; Daum, Moritz M.

    2013-01-01

    Research on early physical reasoning has shown surprising discontinuities in developmental trajectories. Infants possess some skills that seem to disappear and then re-emerge in childhood. It has been suggested that prediction skills required in search tasks might cause these discontinuities (Keen, 2003). We tested 3.5- to 5-year-olds'…

  12. Early Childhood Selected Bibliographies Series. Number 1, Physical.

    ERIC Educational Resources Information Center

    ERIC Clearinghouse on Early Childhood Education, Champaign, IL.

    This is the first in a series of six annotated bibliographies. It has as its general subject the physical aspects of early childhood education and includes three subdivisions: genetics, sensory-motor processes, and growth. Each of the 15 abstracts included has been classified by general and specific subject, by focus of study, and alphabetically…

  13. Sports, Physical Activity and Recreation in Early American History.

    ERIC Educational Resources Information Center

    Ballou, Ralph B.

    Sports and physical recreation activities have been part of American life since the days of the early settlers. Although the settlers were faced with problems of survival, accounts of life in the colonies in the 1600's carry mention of bowling in the streets, play with bows and arrows, and ice skating. Other activities to gain popularity before…

  14. Trajectories of Physical Discipline: Early Childhood Antecedents and Developmental Outcomes

    PubMed Central

    Lansford, Jennifer E.; Criss, Michael M.; Dodge, Kenneth A.; Shaw, Daniel S.; Pettit, Gregory S.; Bates, John E.

    2009-01-01

    This study examined childhood antecedents and developmental outcomes associated with trajectories of mild and harsh parental physical discipline. Interview, questionnaire, and observational data were available from 499 children followed from age 5 to 16 and from 258 children in an independent sample followed from age 5 to 15. Analyses indicated distinct physical discipline trajectory groups that varied in frequency of physical discipline and rate of change. In both samples, family ecological disadvantage differentiated the trajectory groups; in the first sample, early child externalizing also differentiated the groups. Controlling for early childhood externalizing, the minimal/ceasing trajectory groups were associated with the lowest levels of subsequent adolescent antisocial behavior in both samples and with parent-adolescent positive relationship quality in the second sample. PMID:19765007

  15. The early development of neutron diffraction: Science in the wings of the Manhattan Project

    SciTech Connect

    Mason, Thom; Gawne, Timothy J; Nagler, Stephen E; Nestor, Margaret Boone {Bonnie}; Carpenter, John M

    2012-01-01

    Although neutron diffraction was first observed using radioactive decay sources shortly after the discovery of the neutron, it was only with the availability of higher intensity neutron beams from the first nuclear reactors, constructed as part of the Manhattan project, that systematic investigation of Bragg scattering became possible. Remarkably, at a time when the war effort was singularly focused on the development of the atomic bomb, groups working at Oak Ridge and Chicago carried out key measurements and recognized the future utility of neutron diffraction quite independent of its contributions to the measurements of nuclear cross sections. Ernest O. Wollan, Lyle B. Borst, and Walter H. Zinn were all able to observe neutron diffraction in 1944 using the X-10 graphite reactor and the CP-3 heavy water reactor.

  16. The early development of neutron diffraction: science in the wings of the Manhattan Project

    PubMed Central

    Mason, T. E.; Gawne, T. J.; Nagler, S. E.; Nestor, M. B.; Carpenter, J. M.

    2013-01-01

    Although neutron diffraction was first observed using radioactive decay sources shortly after the discovery of the neutron, it was only with the availability of higher intensity neutron beams from the first nuclear reactors, constructed as part of the Manhattan Project, that systematic investigation of Bragg scattering became possible. Remarkably, at a time when the war effort was singularly focused on the development of the atomic bomb, groups working at Oak Ridge and Chicago carried out key measurements and recognized the future utility of neutron diffraction quite independent of its contributions to the measurement of nuclear cross sections. Ernest O. Wollan, Lyle B. Borst and Walter H. Zinn were all able to observe neutron diffraction in 1944 using the X-10 graphite reactor and the CP-3 heavy water reactor. Subsequent work by Wollan and Clifford G. Shull, who joined Wollan’s group at Oak Ridge in 1946, laid the foundations for widespread application of neutron diffraction as an important research tool. PMID:23250059

  17. Physical Aggression During Early Childhood: Trajectories and Predictors

    PubMed Central

    Tremblay, Richard E.; Nagin, Daniel S.; Séguin, Jean R.; Zoccolillo, Mark; Zelazo, Philip D.; Boivin, Michel; Pérusse, Daniel; Japel, Christa

    2012-01-01

    Objectives Physical aggression in children is a major public health problem. Not only is childhood physical aggression a precursor of the physical and mental health problems that will be visited on victims, but also aggressive children themselves are at higher risk of alcohol and drug abuse, accidents, violent crimes, depression, suicide attempts, spouse abuse, and neglectful and abusive parenting. Furthermore, violence commonly results in serious injuries to the perpetrators themselves. Although it is unusual for young children to harm seriously the targets of their physical aggression, studies of physical aggression during infancy indicate that by 17 months of age, the large majority of children are physically aggressive toward siblings, peers, and adults. This study aimed, first, to identify the trajectories of physical aggression during early childhood and, second, to identify antecedents of high levels of physical aggression early in life. Such antecedents could help to understand better the developmental origins of violence later in life and to identify targets for preventive interventions. Methods A random population sample of 572 families with a 5-month-old newborn was recruited. Assessments of physical aggression frequency were obtained from mothers at 17, 30, and 42 months after birth. Using a semiparametric, mixture model, distinct clusters of physical aggression trajectories were identified. Multivariate logit regression analysis was then used to identify which family and child characteristics, before 5 months of age, predict individuals on a high-level physical aggression trajectory from 17 to 42 months after birth. Results Three trajectories of physical aggression were identified. The first was composed of children who displayed little or no physical aggression. These individuals were estimated to account for ~28% of the sample. The largest group, estimated at ~58% of the sample, followed a rising trajectory of modest aggression. Finally, a group

  18. Tracking of physical activity and fitness during the early years.

    PubMed

    Caldwell, Hilary A T; Proudfoot, Nicole A; King-Dowling, Sara; Di Cristofaro, Natascja A; Cairney, John; Timmons, Brian W

    2016-05-01

    The early years are characterized by rapid physical growth and the development of behaviours such as physical activity. The objectives of this study were to assess the 12-month changes in and the tracking of physical activity and fitness in 400 preschoolers (201 boys, 4.5 ± 0.9 years of age). Physical activity data, expressed as minutes per day and as the percentage of time spent at various intensities while wearing an accelerometer, were collected in 3-s epochs for 7 days. Short-term muscle power, assessed with a 10-s modified Wingate Anaerobic Test, was expressed as absolute (W) and relative (W/kg) peak power (PP) and mean power (MP). Aerobic fitness, assessed with the Bruce Protocol progressive treadmill test, was expressed as maximal treadmill time and heart rate recovery (HRR). Light physical activity decreased by 3.2 min/day (p < 0.05), whereas vigorous physical activity increased by 3.7 min/day (p < 0.001), from year 1 to year 2. Physical activity exhibited moderate tracking on the basis of Spearman correlations (r = 0.45-0.59, p < 0.001) and fair tracking on the basis of κ statistics (κ = 0.26-0.38). PP and MP increased from year 1 (PP, 94.1 ± 37.3 W; MP, 84.1 ± 30.9 W) to year 2 (PP, 125.6 ± 36.2 W; MP, 112.3 ± 32.2 W) (p < 0.001) and tracked moderately to substantially (PP, r = 0.89, κ = 0.61; MP, r = 0.86, κ = 0.56). Time to exhaustion on the treadmill increased from 9.4 ± 2.3 min to 11.8 ± 2.3 min (p < 0.001) and tracked strongly (r = 0.82, κ = 0.56). HRR was unchanged at 65 ± 14 beats/min (p = 0.297) and tracked fairly (r = 0.52, κ = 0.23). The findings indicate that fitness tracks better than physical activity over a 12-month period during the early years. PMID:27045869

  19. Physical Mechanisms of Pattern Formation in the Early Chick Embryo

    NASA Astrophysics Data System (ADS)

    Balter, Ariel; Glazier, James; Zaitlen, Benji; Chaplain, Mark; Weijer, Cornelis

    2007-03-01

    Gastrulation marks a critical step in early embryogenesis when the first recognizable patterns are laid down. Although the genome maintains ultimate responsibility for this pattern formation, it cannot actually control the organization of individual cells. The robustness of embryogenic pattern formation suggests that a few simple, physical mechanisms are unleashed and that self-organization results. We perform numerical simulations of early chick gastrulation using an agent based method in which individual cells interact via a handful of behaviors including adhesivity, secretion and chemotaxis. Through these simulations we have identified certain behaviors as being important for various stages and morphological events. For instance, experimental results on primitive streak formation are best reproduced by a model in which the Kohler's Sickle secretes a chemo repellant for streak tip cells, and cell polarization appears to be important for initiating polonaise motion during streak elongation.

  20. The early universe as a probe of new physics

    NASA Astrophysics Data System (ADS)

    Bird, Christopher Shane

    The Standard Model of Particle Physics has been verified to unprecedented precision in the last few decades. However there are still phenomena in nature which cannot be explained, and as such new theories will be required. Since terrestrial experiments are limited in both the energy and precision that can be probed, new methods are required to search for signs of physics beyond the Standard Model. In this dissertation, I demonstrate how these theories can be probed by searching for remnants of their effects in the early Universe. In particular I focus on three possible extensions of the Standard Model: the addition of massive neutral particles as dark matter, the addition of charged massive particles, and the existence of higher dimensions. For each new model, I review the existing experimental bounds and the potential for discovering new physics in the next generation of experiments. For dark matter, I introduce six simple models which I have developed, and which involve a minimum amount of new physics, as well as reviewing one existing model of dark matter. For each model I calculate the latest constraints from astrophysics experiments, nuclear recoil experiments, and collider experiments. I also provide motivations for studying sub-GeV mass dark matter, and propose the possibility of searching for light WIMPs in the decay of B-mesons and other heavy particles. For charged massive relics, I introduce and review the recently proposed model of catalyzed Big Bang nucleosynthesis. In particular I review the production of 6Li by this mechanism, and calculate the abundance of 7Li after destruction of 7Be by charged relics. The result is that for certain natural relics CBBN is capable of removing tensions between the predicted and observed 6Li and 7Li abundances which are present in the standard model of BBN. For extra dimensions, I review the constraints on the ADD model from both astrophysics and collider experiments. I then calculate the constraints on this model

  1. Subreflector extension for improved efficiencies in Cassegrain antennas - GTD/PO analysis. [Geometrical Theory of Diffraction/Physical Optics

    NASA Technical Reports Server (NTRS)

    Rahmat-Samii, Yahya

    1986-01-01

    Both offset and symmetric Cassegrain reflector antennas are used in satellite and ground communication systems. It is known that the subreflector diffraction can degrade the performance of these reflectors. A geometrical theory of diffraction/physical optics analysis technique is used to investigate the effects of the extended subreflector, beyond its optical rim, on the reflector efficiency and far-field patterns. Representative numerical results are shown for an offset Cassegrain reflector antenna with different feed illumination tapers and subreflector extensions. It is observed that for subreflector extensions as small as one wavelength, noticeable improvements in the overall efficiencies can be expected. Useful design data are generated for the efficiency curves and far-field patterns.

  2. BOOK REVIEW: The Physics of the Early Universe

    NASA Astrophysics Data System (ADS)

    Scott, Douglas

    2007-11-01

    The physics of the very small and the very large were successfully brought together in the 1980s through the idea of 'the universe as a particle accelerator'. The manifesto of this new campaign was laid out in the book 'The Early Universe' by Kolb and Turner in 1990. For at least the next decade that book was to be found on the shelves of every theorist (and many experimentalists) who professed an interest in this topic. But science marches on, and the last 10 15 years has seen an explosion in our understanding of the physics of the very earliest times and the very largest scales. Experimentally our world-view has changed utterly, through exquisitely precise measurements of the cosmic microwave background, galaxy clustering and supernova distances, with a refinement of the basic inflationary big bang paradigm into the new 'standard cosmological model'. And in tandem with these changes has been the development of new theoretical ideas, particularly involving dark energy and connections between string/brane theory and cosmology. So what is the new book for the shelves of today's cohort of young Rockys and Mikes? Despite a recent number of promising-sounding cosmology books, there is nothing at the advanced level which is broad enough to be a general introduction to the 'early universe' topic. Perhaps the best of the bunch is 'The Physics of the Early Universe', edited by E Papantonopoulos as part of Springer's series 'Lecture notes in physics'. This is a set of 9 review articles given as part of a 2003 summer school on Syros Island, Greece. Although far from perfect, the core of this book provides a solid introduction to current research in early universe physics, which should be useful for PhD students or postdoctoral researchers who want the real thing. The book starts with a competent introduction by Kyriakos Tamvakis, serving essentially as a summary of where we were in Kolb and Turner's text. We have learned since then, however, that inflation is really all

  3. Illinois Early Learning Project Tip Sheets: Physical Development and Health.

    ERIC Educational Resources Information Center

    2003

    The Illinois Early Learning Project (IEL) is funded by the Illinois State Board of Education to provide information resources on early learning and training related to implementing the Illinois Early Learning Standards for parents and for early childhood personnel in all settings. The IEL tip sheets offer suggestions to parents and early childhood…

  4. The early fluidic and optical physics of cytometry.

    PubMed

    Watson, J V

    1999-02-15

    All forms of cytometry, depend on the basic laws of physics, including those of fluidics, optics, and electronics, most of which were established centuries ago. Flow cytometry depends critically on the fluidics presenting each individual cell with precision to the sensing volume. This is intersected by a high-intensity light source, and light scattering and fluorescence from suitably stained constituents in each cell are captured by the light-collecting optics and measured. The works and observations of Bernoulli and Euler in the 18th century, Reynolds in the 19th century, and Crosland-Taylor in the 20th century in the field of fluid dynamics laid the foundations for hydrodynamic focussing, which is the primary prerequisite for presenting individual cells to the sensing volume. In addition, electrostatic cell sorters must have the ability to generate stable droplet formation in the jet-stream issuing from the flow chamber nozzle. The origins here can be traced to work carried out in the early to mid-19th century by Savart, Magnus, and Thomson. Flow, image, and confocal cytometry are all dependent on the laws of optics, including those of reflection and refraction as well as numerous other optical principles. The observations and works of Socrates, Ptolemy, Snel, and Descartes between about BC 370 and 1637 were of seminal importance in developing the laws of reflection and refraction. In the mid-17th century Hooke illustrated the power of magnifying glasses and microscopy in his Micrographia and Newton was responsible for explaining colours in the spectrum. Huygens, toward the end of the 17th century, put forward the concept of point source light propagation contributing to a wave front. Finally, Thomas Young, early in the 19th century, established the wave form of light from interference patterns. Most people will be familiar with some of these discoveries and the investigators who carried out the work; some people will be familiar with all of these. However, very

  5. X-Ray Diffraction of Intermetallic Compounds: A Physical Chemistry Laboratory Experiment

    ERIC Educational Resources Information Center

    Varberg, Thomas D.; Skakuj, Kacper

    2015-01-01

    Here we describe an experiment for the undergraduate physical chemistry laboratory in which students synthesize the intermetallic compounds AlNi and AlNi3 and study them by X-ray diffractometry. The compounds are synthesized in a simple one-step reaction occurring in the solid state. Powder X-ray diffractograms are recorded for the two compounds…

  6. Assessing the Physical Environment in an Early Childhood Program.

    ERIC Educational Resources Information Center

    Turner, Joy

    1999-01-01

    Describes Montessori's vision of developmentally appropriate physical environment, considers some effective design principles and characteristics of environments for young children, and identifies criteria for assessing the indoor and outdoor physical environments. (Author/KB)

  7. Affordances for Risk-Taking and Physical Activity in Australian Early Childhood Education Settings

    ERIC Educational Resources Information Center

    Little, Helen; Sweller, Naomi

    2015-01-01

    Motor competence and physical activity (PA) patterns are established during the early childhood years. Early childhood education (ECE) settings are an important context for children's engagement in physically active play. This paper reports the findings from an online survey examining resources, spaces and affordances for PA and risk-taking in…

  8. Move to Learn, Learn to Move: Prioritizing Physical Activity in Early Childhood Education Programming

    ERIC Educational Resources Information Center

    Lu, Chunlei; Montague, Brandi

    2016-01-01

    The global childhood trend towards obesity and unhealthy lifestyles is a growing concern. Childcare settings have been identified as the most influential factors for children's physical activity, and physical activity habits are better formed and maintained if started in early childhood. As a result, early childhood education environments are in…

  9. Promoting Professional Development for Physical Therapists in Early Intervention

    ERIC Educational Resources Information Center

    Catalino, Tricia; Chiarello, Lisa A.; Long, Toby; Weaver, Priscilla

    2015-01-01

    Early intervention service providers are expected to form cohesive teams to build the capacity of a family to promote their child's development. Given the differences in personnel preparation across disciplines of service providers, the Early Childhood Personnel Center is creating integrated and comprehensive professional development models for…

  10. An Experimental Test of Parenting Practices as a Mediator of Early Childhood Physical Aggression

    ERIC Educational Resources Information Center

    Brotman, Laurie Miller; O'Neal, Colleen R.; Huang, Keng-Yen; Gouley, Kathleen Kiely; Rosenfelt, Amanda; Shrout, Patrick E.

    2009-01-01

    Background: Parenting practices predict early childhood physical aggression. Preventive interventions that alter parenting practices and aggression during early childhood provide the opportunity to test causal models of early childhood psychopathology. Although there have been several informative preventive intervention studies that test mediation…

  11. Early Field Experience in Physical Education-Teacher Education Undergraduate Programs.

    ERIC Educational Resources Information Center

    Stewart, Michael J.

    1986-01-01

    The importance of early field experience for preservice physical education teachers is discussed, the program at the University of Nebraska-Omaha is described, and suggestions for gaining cooperation from nearby school systems are made. (MT)

  12. The Early Universe and High-Energy Physics.

    ERIC Educational Resources Information Center

    Schramm, David N.

    1983-01-01

    Many properties of new particle field theories can only be tested by comparing their predictions about the physical conditions immediately after the big bang with what can be reconstructed about this event from astronomical data. Facts/questions about big bang, unified field theories, and universe epochs/mass are among the topics discussed. (JN)

  13. Trajectories of Physical Discipline: Early Childhood Antecedents and Developmental Outcomes

    ERIC Educational Resources Information Center

    Lansford, Jennifer E.; Criss, Michael M.; Dodge, Kenneth A.; Shaw, Daniel S.; Pettit, Gregory S.; Bates, John E.

    2009-01-01

    This study examined childhood antecedents and developmental outcomes associated with trajectories of mild and harsh parental physical discipline. Interview, questionnaire, and observational data were available from 499 children followed from ages 5 to 16 and from 258 children in an independent sample followed from ages 5 to 15. Analyses indicated…

  14. Physical Aggression in Early Marriage: Prerelationship and Relationship Effects.

    ERIC Educational Resources Information Center

    O'Leary, K. Daniel; And Others

    1994-01-01

    Predicted spousal physical aggression at 30 months after marriage for 393 young couples. Prerelationship predictor variables were history of violence in family of origin, aggression against others during childhood and adolescence, and personality characteristics. Relationship predictor variables were marital discord and spouse-specific…

  15. Locating Quality Physical Education in Early Years Pedagogy

    ERIC Educational Resources Information Center

    Marsden, Elizabeth; Weston, Carrie

    2007-01-01

    Government Ministers, health care professionals and sporting organisations throughout the UK are presently engaged in the promotion of extending the length of time each school child spends participating in quality physical education. Agendas may differ from a crackdown on obesity and sedentary lifestyles to basking in reflected glory of British…

  16. The Influences of Pre-Professional Socialization on Early Career Physical Educators

    ERIC Educational Resources Information Center

    Flory, Sara B.; McCaughtry, Nate

    2014-01-01

    The purpose of this study was to examine how three PE teachers' personal biographies before their formal teacher education programs influenced their early careers in urban schools. Using occupational socialization theory and cultural relevance theory, we conducted in-depth interviews and observed early career physical education teachers who…

  17. Soil and Rock Physical Properties at the Mars Exploration Rover Landing Sites: Early Returns

    NASA Technical Reports Server (NTRS)

    Ming, D. W.; Anderson, R. C.; Arvidson, R. E.; Bell, J. F., III; Biesiadecki, J.; Christensen, P. H.; Gorevan, S. P.; Ehlmann, B. L.; Guinness, E. A.; Graff, T. G.

    2004-01-01

    The purpose of this paper is to report the 'early returns' on the physical properties of soil units and rocks at the MER landing sites. Because we are still very early in the mission at Meridiani Planum, results from the Gusev Crater Landing Site are emphasized here.

  18. Recommended Practices for Promoting Physical Activity in Early Childhood Education Settings

    ERIC Educational Resources Information Center

    Wright, Paul M.; Stork, Steve

    2013-01-01

    Although the importance of physical development as an integrated part of early childhood education is well understood, many early childhood teachers lack the specific background and training in this area. To fill this gap, this article presents a framework of recommended practices and a corresponding assessment tool. The Head Start Body Start…

  19. Nuclear and particle physics in the early universe

    NASA Technical Reports Server (NTRS)

    Schramm, D. N.

    1981-01-01

    Basic principles and implications of Big Bang cosmology are reviewed, noting the physical evidence of a previous universe temperature of 10,000 K and theoretical arguments such as grand unification decoupling indicating a primal temperature of 10 to the 15th eV. The Planck time of 10 to the -43rd sec after the Big Bang is set as the limit before which gravity was quantized and nothing is known. Gauge theories of elementary particle physics are reviewed for successful predictions of similarity in weak and electromagnetic interactions and quantum chromodynamic predictions for strong interactions. The large number of photons in the universe relative to the baryons is considered and the grand unified theories are cited as showing the existence of baryon nonconservation as an explanation. Further attention is given to quark-hadron phase transition, the decoupling for the weak interaction and relic neutrinos, and Big Bang nucleosynthesis.

  20. Fibre Diffraction Analysis of Skin Offers a Very Early and Extremely Accurate Diagnostic Test for Prostate Cancer

    DOE PAGESBeta

    James, Veronica J.; O’Malley Ford, Judith M.

    2014-01-01

    Double blind analysis of a batch of thirty skin tissue samples from potential prostate cancer sufferers correctly identified all “control” patients, patients with high and low grade prostate cancers, the presence of benign prostate hyperplasia (BPH), perineural invasions, and the one lymphatic invasion. Identification was by analysis of fibre diffraction patterns interpreted using a schema developed from observations in nine previous studies. The method, schema, and specific experiment results are reported in this paper, with some implications then drawn.

  1. Pilot-Testing CATCH Early Childhood: A Preschool-Based Healthy Nutrition and Physical Activity Program

    ERIC Educational Resources Information Center

    Sharma, Shreela; Chuang, Ru-Jye; Hedberg, Ann Marie

    2011-01-01

    Background: The literature on theoretically-based programs targeting healthy nutrition and physical activity in preschools is scarce. Purpose: To pilot test CATCH Early Childhood (CEC), a preschool-based nutrition and physical activity program among children ages three to five in Head Start. Methods: The study was conducted in two Head Start…

  2. Concerns of Preservice Physical Education Teachers Participating in an Early Field Experience

    ERIC Educational Resources Information Center

    Young, Shawna

    2012-01-01

    The purpose of this study was to examine the frequency of concerns by type (self, task, and impact) of preservice physical education teachers participating in an early field experience. Participants (n = 52) taught three physical education lessons in a junior high school. Following each teaching episode, participants wrote concerns in their…

  3. Embedding Physical Activity and Nutrition in Early Care and Education Programs

    ERIC Educational Resources Information Center

    Deiner, Penny Low; Qiu, Wei

    2007-01-01

    The infant and toddler years provide a window of opportunity to establish healthy habits as part of daily routines and activities that prevent childhood obesity. Early care and education programs have the opportunity to make a significant impact on physical development when they promote healthy eating and physical activity in their daily routines.…

  4. An Empirical Investigation of the Dimensionality of the Physical Literacy Environment in Early Childhood Classrooms

    ERIC Educational Resources Information Center

    Dynia, Jaclyn M.; Schachter, Rachel E.; Piasta, Shayne B.; Justice, Laura M.; O'Connell, Ann A.; Yeager Pelatti, Christina

    2016-01-01

    This study investigated the dimensionality of the physical literacy environment of early childhood education classrooms. Data on the classroom physical literacy environment were collected from 245 classrooms using the Classroom Literacy Observation Profile. A combination of confirmatory and exploratory factor analysis was used to identify five…

  5. A physical and chemical model of early lunar history

    NASA Technical Reports Server (NTRS)

    Hubbard, N. J.; Minear, J. W.

    1975-01-01

    A 'cool' thermal model of the moon's early history is discussed in terms of lunar petrology. Heat from the totally molten outer half of the moon's volume was, according to the model, lost to space and to the lunar interior, so that, barring additions of heat from external sources, all petrogenesis operating exclusively on material of the initially totally molten zone must have occured in an environment of decreasing temperatures. Mare basalts would result from hybridization by migration, mixing, and reequilibration of a variety of intercumulus liquids. Evidence is considered for the layered structure and a significant structural boundary that should result from differentiation of the approximately 350-km-thick initially totally molten zone. Magnetization of lunar rocks is considered.

  6. Early and current physical activity: relationship with intima-media thickness and metabolic variables in adulthood.

    PubMed

    Lima, Manoel C S; Barbosa, Maurício F; Diniz, Tiego A; Codogno, Jamile S; Freitas Júnior, Ismael F; Fernandes, Rômulo A

    2014-08-29

    Background: It is unclear whether early physical activity has a greater influence on intima-media thickness and metabolic variables than current physical activity. Objective: To analyze the relationship between current and early physical activity, metabolic variables, and intima-media thickness measures in adults. Method: The sample was composed of 55 healthy subjects of both sexes (33 men and 22 women). Total body fat and trunk fat were estimated by dual-energy X-ray absorptiometry. Carotid and femoral intima-media thickness were measured using a Doppler ultrasound device. A 12-hour fasting blood sample collection was taken (fasting glucose and lipid profile). Early physical activity was assessed through face-to-face interview, and the current physical activity was assessed by pedometer (Digi-Walker Yamax, SW200), which was used for a period of seven days. Results: Current physical activity was negatively related to total cholesterol (rho=-0.31), while early physical activity was negatively related to triglycerides (rho=-0.42), total cholesterol (rho=-0.28), very low density lipoprotein (rho=-0.44), and carotid intima-media thickness (rho=-0.50). In the multivariate model, subjects engaged in sports activities during early life had lower values of very low density lipoprotein (b=-8.74 [b=-16.1; -1.47]) and carotid intima-media thickness (b=-0.17 [95%CI: -0.28; -0.05]). Conclusion: Early 95%CI physical activity has a significant influence on carotid intima-media thickness, regardless of the current physical activity. PMID:25185030

  7. Early and current physical activity: relationship with intima-media thickness and metabolic variables in adulthood

    PubMed Central

    Lima, Manoel C. S.; Barbosa, Maurício F.; Diniz, Tiego A.; Codogno, Jamile S.; Freitas, Ismael F.; Fernandes, Rômulo A.

    2014-01-01

    Background: It is unclear whether early physical activity has a greater influence on intima-media thickness and metabolic variables than current physical activity. Objective: To analyze the relationship between current and early physical activity, metabolic variables, and intima-media thickness measures in adults. Method: The sample was composed of 55 healthy subjects of both sexes (33 men and 22 women). Total body fat and trunk fat were estimated by dual-energy X-ray absorptiometry. Carotid and femoral intima-media thickness were measured using a Doppler ultrasound device. A 12-hour fasting blood sample collection was taken (fasting glucose and lipid profile). Early physical activity was assessed through face-to-face interview, and the current physical activity was assessed by pedometer (Digi-Walker Yamax, SW200), which was used for a period of seven days. Results: Current physical activity was negatively related to total cholesterol (rho=-0.31), while early physical activity was negatively related to triglycerides (rho=-0.42), total cholesterol (rho=-0.28), very low density lipoprotein (rho=-0.44), and carotid intima-media thickness (rho=-0.50). In the multivariate model, subjects engaged in sports activities during early life had lower values of very low density lipoprotein (b=-8.74 [b=-16.1; -1.47]) and carotid intima-media thickness (b=-0.17 [95%CI: -0.28; -0.05]). Conclusion: Early 95%CI physical activity has a significant influence on carotid intima-media thickness, regardless of the current physical activity. PMID:25372009

  8. Modeling and Reality in Early Twentieth-Century Physics

    NASA Astrophysics Data System (ADS)

    Seth, Suman

    2011-04-01

    Towards the end of 1913, Arnold Sommerfeld, Professor of theoretical physics at Munich University, sent a letter of congratulations to a young Niels Bohr. The Dane's now-classic trilogy of papers, which coupled Rutherford's conception of the atom with a ``planetary'' configuration of electrons, had just appeared. Sommerfeld saw the calculation of the Rydberg constant as a singular triumph and immediately spotted an opportunity to try to explain the Zeeman effect. Yet he also sounded a note of caution, confessing that he remained ``somewhat skeptical'' of atomic models in general. In this, of course, he was hardly alone. Bohr's atom was a particularly egregious example of a peculiar model, one requiring what even its creator considered ``horrid assumptions.'' Nonetheless, success bred conviction. Expanding upon Bohr's original ideas, Sommerfeld soon produced the so-called ``Bohr-Sommerfeld quantization conditions,'' using them to calculate a myriad of results. Experimental evidence, Sommerfeld argued in 1915, showed that quantised electron-paths ``correspond exactly to reality'' and possess ``real existence.'' This kind of realism would not, of course, last long. In 1925, Werner Heisenberg (earlier a student of Sommerfeld's) made scepticism about the details of the Bohr model into a methodological dictum, one later enshrined in the ``Copenhagen interpretation'' of quantum mechanics. This paper uses Sommerfeld's work from the turn of the twentieth century to the mid-1920s as a window onto a landscape involving multiple contestations over the legitimacy of atomic modelling. The surprise that greeted Heisenberg's and others' phenomenological insistences, we will see, can only be understood with reference to what should be considered a ``realist interlude'' in the history of twentieth century atomic physics, one inspired by the astonishing successes of Rutherford's and Bohr's imaginings.

  9. Measuring Physical Activity in Older Adults with and without Early Stage Alzheimer’s Disease

    PubMed Central

    Watts, Amber S.; Vidoni, Eric D.; Loskutova, Natalia; Johnson, David K.; Burns, Jeffrey M.

    2013-01-01

    We compared subjective reports of physical activity with objective measures of physical fitness including cardiorespiratory capacity, body composition, and physical performance in 146 older adults with and without early stage Alzheimer’s disease (ESAD). Respondents reported primarily unstructured and low-intensity activities, including walking and housework. Individuals with ESAD participated in fewer and lower intensity physical activities than those without ESAD. In those without ESAD, housework was related to lower body mass index, leisure walking was related to faster speed on a timed walking test, and participation in sports was related to higher peak oxygen intake. In individuals with ESAD, reported physical activities did not predict any of the physical fitness, body composition, or physical performance measures. We conclude that measures of physical activity require expansion of unstructured and low intensity activities to improve sensitivity in sedentary populations, especially in older adults with ESAD. PMID:24062599

  10. Early Childhood Policy Focus: Healthy Eating and Physical Activity. Early Childhood Highlights. Volume 2, Issue 3

    ERIC Educational Resources Information Center

    Murphey, David; Mackintosh, Bonnie; McCoy-Roth, Marci

    2011-01-01

    The importance of good nutrition and exercise is well known, and parents have long worried about their children's diets and envied their high energy levels. Like so many life style habits, patterns of nutrition and exercise behaviors are typically established in early childhood. Poor diet and lack of exercise contribute to obesity, which has been…

  11. A short note on physical properties to irradiated nuclear fuel by means of X-ray diffraction and neutron scattering techniques

    SciTech Connect

    Abdullah, Yusof Husain, Hishamuddin; Hak, Cik Rohaida Che; Alias, Nor Hayati; Yusof, Mohd Reusmaazran; Kasim, Norasiah Ab; Zali, Nurazila Mat; Mohamed, Abdul Aziz

    2015-04-29

    For nuclear reactor applications, understanding the evolution of the fuel materials microstructure during irradiation are of great importance. This paper reviews the physical properties of irradiated nuclear fuel analysis which are considered to be of most importance in determining the performance behavior of fuel. X-rays diffraction was recognize as important tool to investigate the phase identification while neutron scattering analyses the interaction between uranium and other materials and also investigation of the defect structure.

  12. Z{sup '} physics with early LHC data

    SciTech Connect

    Accomando, Elena; Belyaev, Alexander; Fedeli, Luca; King, Stephen F.; Shepherd-Themistocleous, Claire

    2011-04-01

    We discuss the prospects for setting limits on or discovering spin-1 Z{sup '} bosons using early LHC data at 7 TeV. Our results are based on the narrow width approximation in which the leptonic Drell-Yan Z{sup '} boson production cross section only depends on the Z{sup '} boson mass together with two parameters c{sub u} and c{sub d}. We carefully discuss the experimental cuts that should be applied and tabulate the theoretical next-to-next-to-leading order corrections which must be included. Using these results the approach then provides a safe, convenient, and unbiased way of comparing experiment to theoretical models which avoids any built-in model-dependent assumptions. We apply the method to three classes of perturbative Z{sup '} boson benchmark models: E{sub 6} models, left-right symmetric models, and sequential standard models. We generalize each class of model in terms of mixing angles which continuously parametrize linear combinations of pairs of generators and lead to distinctive orbits in the c{sub u}-c{sub d} plane. We also apply this method to the strongly coupled four-site benchmark model in which two Z{sup '} bosons are predicted. By comparing the experimental limits or discovery bands to the theoretical predictions on the c{sub u}-c{sub d} plane, we show that the LHC at 7 TeV with integrated luminosity of 500 pb{sup -1} will greatly improve on current Tevatron mass limits for the benchmark models. If a Z{sup '} is discovered our results show that measurement of the mass and cross section will provide a powerful discriminator between the benchmark models using this approach.

  13. Early developments: Particle physics aspects of cosmic rays

    NASA Astrophysics Data System (ADS)

    Grupen, Claus

    2014-01-01

    Cosmic rays is the birthplace of elementary particle physics. The 1936 Nobel prize was shared between Victor Hess and Carl Anderson. Anderson discovered the positron in a cloud chamber. The positron was predicted by Dirac several years earlier. In subsequent cloud chamber investigations Anderson and Neddermeyer saw the muon, which for some time was considered to be a candidate for the Yukawa particle responsible for nuclear binding. Measurements with nuclear emulsions by Lattes, Powell, Occhialini and Muirhead clarified the situation by the discovery of the charged pions in cosmic rays. The cloud chamber continued to be a powerful instrument in cosmic ray studies. Rochester and Butler found V's, which turned out to be shortlived neutral kaons decaying into a pair of charged pions. Also Λ's, Σ's, and Ξ's were found in cosmic rays. But after that accelerators and storage rings took over. The unexpected renaissance of cosmic rays started with the search for solar neutrinos and the observation of the supernova 1987A. Cosmic ray neutrino results were best explained by the assumption of neutrino oscillations opening a view beyond the standard model of elementary particles. After 100 years of cosmic ray research we are again at the beginning of a new era, and cosmic rays may contribute to solve the many open questions, like dark matter and dark energy, by providing energies well beyond those of accelerators.

  14. Maximizing the DUNE early physics output with current experiments

    NASA Astrophysics Data System (ADS)

    Ghosh, Monojit; Goswami, Srubabati; Raut, Sushant K.

    2016-03-01

    The deep underground neutrino experiment (DUNE) is a proposed next generation superbeam experiment at Fermilab. Its aims include measuring the unknown neutrino oscillation parameters—the neutrino mass hierarchy, the octant of the mixing angle θ _{23}, and the CP-violating phase δ _{CP}. The current and upcoming experiments T2K, NOν A, and ICAL@INO will also be collecting data for the same measurements. In this paper, we explore the sensitivity reach of DUNE in combination with these other experiments. We evaluate the least exposure required by DUNE to determine the above three unknown parameters with reasonable confidence. We find that for each case, the inclusion of data from T2K, NOν A, and ICAL@INO help to achieve the same sensitivity with a reduced exposure from DUNE thereby helping to economize the configuration. Further, we quantify the effect of the proposed near detector on systematic errors and study the consequent improvement in sensitivity. We also examine the role played by the second oscillation cycle in furthering the physics reach of DUNE. Finally, we present an optimization study of the neutrino-antineutrino running of DUNE.

  15. Signals of Early-Universe Physics in Cosmology

    NASA Astrophysics Data System (ADS)

    Cuadburn, Sarah Elizabeth

    This is a thesis on theoretical cosmology. The first and largest part is a study of cosmic strings, in particular their dynamics and signals in higher dimensional spacetimes. The second part is a study of black holes in a quintessence background. Cosmic strings are predicted by models of the early universe. They were thought to arise, originally, from Grand Unified Theories, and more recently from brane inflationary models based in string theory. In Chapter 3 we find exact solutions for cosmic string loop trajectories in higher dimensions, and find the regions of parameter space for which cusps exist. We find that winding the internal dimensions slows the average velocity of string loops, and conjecture that the periodicity of internal space may contribute to self-intersections. In Chapter 4, we calculate the gravitational wave signal from cosmic string cusps in higher dimensions, and find it is much reduced relative to the 4D case. The main reason for this is the large reduction in the probability of cusps occurring on loops in higher dimensions, as well as a slight reduction in signal from individual cusps. In Chapter 5, we study cosmic string trajectories in warped spacetimes, such as may be found in realistic brane inflation models. We find that contrary to claims in the literature, the warping of the internal space does not prevent the internal motion of strings. The energy associated with the warping of spacetime means that the energy of a loop appears to change over time from our 4D perspective. Finally, in Chapter 6, we find an analytic, general-relativistic solution describing a black hole in a quintessence universe. Quintessence is a model of late-time cosmic acceleration in which expansion is sourced by a scalar field. Our solution shows the interaction between this scalar field and a black hole. The scalar field is shown to continue its cosmological "rolling" behaviour everywhere, including on the black hole event horizon, and the black hole is shown

  16. Capitalizing on the Teachable Moment: Osteoarthritis Physical Activity and Exercise Net for Improving Physical Activity in Early Knee Osteoarthritis

    PubMed Central

    Lineker, Sydney; Cibere, Jolanda; Crooks, Valorie A; Jones, Catherine A; Kopec, Jacek A; Lear, Scott A; Pencharz, James; Rhodes, Ryan E; Esdaile, John M

    2013-01-01

    with OA tend to be more motivated to adopt an active lifestyle (ie, at the early stage of OA). Our approach, which consisted of the identification of early knee OA followed immediately by an online intervention that directly targets physical inactivity, can be easily implemented across communities. Conclusions Our online intervention directly targets physical inactivity at a time when the joint damage tends to be mild. If OPEN is found to be effective in changing long-term physical activity behaviors, it opens further opportunities to promote early diagnosis and to implement lifestyle interventions. Trial Registration Clinicaltrial.gov: NCT01608282; http://clinicaltrials.gov/ct2/show/NCT01608282 (Archived by WebCite at http://www.webcitation.org/6G7sBBayI) PMID:23659903

  17. Early Physical Rehabilitation in the ICU: A Review for the Neurohospitalist

    PubMed Central

    Mendez-Tellez, Pedro A.; Nusr, Rasha; Feldman, Dorianne; Needham, Dale M.

    2012-01-01

    Advances in critical care have resulted in improved intensive care unit (ICU) mortality. However, improved ICU survival has resulted in a growing number of ICU survivors living with long-term sequelae of critical illness, such as impaired physical function and quality of life (QOL). In addition to critical illness, prolonged bed rest and immobility may lead to severe physical deconditioning and loss of muscle mass and muscle weakness. ICU-acquired weakness is associated with increased duration of mechanical ventilation and weaning, longer ICU and hospital stay, and increased mortality. These physical impairments may last for years after ICU discharge. Early Physical Medicine and Rehabilitation (PM&R) interventions in the ICU may attenuate or prevent the weakness and physical impairments occurring during critical illness. This article reviews the evidence regarding safety, feasibility, barriers, and benefits of early PM&R interventions in ICU patients and discusses the limited existing data on early PM&R in the neurological ICU and future directions for early PM&R in the ICU. PMID:23983871

  18. A Longitudinal Examination of the Influence of Maturation on Physical Self-Perceptions and the Relationship with Physical Activity in Early Adolescent Girls

    ERIC Educational Resources Information Center

    Knowles, Ann-Marie; Niven, Ailsa G.; Fawkner, Samantha G.; Henretty, Joan M.

    2009-01-01

    This longitudinal study investigated the influence of maturation on physical self-perceptions and the relationship with physical activity in early adolescent girls (N = 150; mean age = 12.79 plus or minus 0.31). Physical characteristics were measured and participants completed the Physical Activity Questionnaire for Children, the Children and…

  19. The interaction between early-life body size and physical activity on risk of breast cancer

    PubMed Central

    Oh, Hannah; Boeke, Caroline E.; Tamimi, Rulla M.; Smith-Warner, Stephanie A.; Wang, Molin; Willett, Walter C.; Eliassen, A. Heather

    2014-01-01

    While early-life body leanness is associated with increased breast cancer risk, early-life physical activity may protect against breast cancer. We examined whether the excess risk among lean girls is modified by their levels of prior, concurrent, or future physical activity. We conducted an analysis among 74,723 women in the Nurses’ Health Study II (follow-up 1997–2011). Participants recalled their body size at ages 5, 10, and 20 years in 1989 using a 9-level pictogram (level 1: most lean). In 1997, they reported adolescent levels of physical activity (ages 12–13 and 14–17 years). Cox proportional hazards models estimated the overall association of body size with breast cancer risk and assessed interactions of adolescent physical activity with body size at three different age periods (5–10, 10–20, and 20 years), adjusting for early-life and adult risk factors for breast cancer. Regardless of levels of adolescent physical activity, early-life body leanness (level 1–2 vs. 4.5+) was significantly associated with higher breast cancer risk. The association was slightly attenuated among those who were active (60+ MET-hr/wk) during adolescence compared to those who were inactive (<30 MET-hr/wk) (body size at ages 5–10 years: hazard ratio=1.37, 95% confidence interval=1.04–1.81 vs. 1.66, 1.29–2.12), but the interaction was not significant (p=0.72). The results were similar for body size at three different age periods. Being lean during early life is a risk factor for breast cancer among both inactive and active girls. Adolescent physical activity did not significantly modify the association, although some interaction cannot be excluded. PMID:25335465

  20. The interaction between early-life body size and physical activity on risk of breast cancer.

    PubMed

    Oh, Hannah; Boeke, Caroline E; Tamimi, Rulla M; Smith-Warner, Stephanie A; Wang, Molin; Willett, Walter C; Eliassen, A Heather

    2015-08-01

    While early-life body leanness is associated with increased breast cancer risk, early-life physical activity may protect against breast cancer. We examined whether the excess risk among lean girls is modified by their levels of prior, concurrent, or future physical activity. We conducted an analysis among 74,723 women in the Nurses' Health Study II (follow-up 1997-2011). Participants recalled their body size at ages 5, 10 and 20 years in 1989 using a 9-level pictogram (Level 1 most lean). In 1997, they reported adolescent levels of physical activity (ages 12-13 and 14-17 years). Cox proportional hazards models estimated the overall association of body size with breast cancer risk and assessed interactions of adolescent physical activity with body size at three different age periods (5-10, 10-20 and 20 years), adjusting for early-life and adult risk factors for breast cancer. Regardless of levels of adolescent physical activity, early-life body leanness (level 1-2 vs. 4.5+) was significantly associated with higher breast cancer risk. The association was slightly attenuated among those who were active (60+ MET-hr/wk) during adolescence compared to those who were inactive (<30 MET-hr/wk) (body size at ages 5-10 years: hazard ratio = 1.37, 95% confidence interval = 1.04-1.81 vs. 1.66, 1.29-2.12), but the interaction was not significant (p = 0.72). The results were similar for body size at three different age periods. Being lean during early life is a risk factor for breast cancer among both inactive and active girls. Adolescent physical activity did not significantly modify the association, although some interaction cannot be excluded. PMID:25335465

  1. Environmental Influences on Preschoolers' Physical Activity Levels in Various Early-Learning Facilities

    ERIC Educational Resources Information Center

    Vanderloo, Leigh M.; Tucker, Patricia; Johnson, Andrew M.; Burke, Shauna M.; Irwin, Jennifer D.

    2015-01-01

    Purpose: This study aimed to: (a) compare the physical activity (PA) levels (i.e., moderate-to-vigorous PA [MVPA] and total PA [TPA]) of preschoolers in 3 different early-learning environments (center-based childcare, home-based childcare, and full-day kindergarten [FDK]); and (b) assess which characteristics (e.g., play equipment, policies, etc.)…

  2. Exposure to Childhood Sexual and Physical Abuse and Adjustment in Early Adulthood

    ERIC Educational Resources Information Center

    Fergusson, David M.; Boden, Joseph M.; Horwood, L. John

    2008-01-01

    Objective: This research examined linkages between exposure to childhood sexual abuse (CSA) and childhood physical punishment/abuse (CPA) and mental health issues in early adulthood. Method: The investigation analyzed data from a birth cohort of over 1,000 New Zealand young adults studied to the age of 25. Results: Exposure to CSA and CPA was…

  3. Sixty Minutes of Physical Activity per Day Included within Preschool Academic Lessons Improves Early Literacy

    ERIC Educational Resources Information Center

    Kirk, Stacie M.; Kirk, Erik P.

    2016-01-01

    Background: The effects of increases in physical activity (PA) on early literacy skills in preschool children are not known. Methods: Fifty-four African-American preschool children from a low socioeconomic urban Head Start participated over 8 months. A 2-group, quasi-experimental design was used with one preschool site participating in the PA…

  4. Psychosocial Correlates of Physical and Sedentary Activities of Early Adolescent Youth

    ERIC Educational Resources Information Center

    Rusby, Julie C.; Westling, Erika; Crowley, Ryann; Light, John M.

    2014-01-01

    This study examines physical and sedentary activities of early adolescent boys and girls using Ecological Momentary Assessment (EMA), a method that can link mood and behaviors in specific social situations. Twenty-seven assessments were collected across 7 days from 82 participating adolescents, three times in seventh grade and one time in eighth…

  5. Early Parenting and Children's Relational and Physical Aggression in the Preschool and Home Contexts

    ERIC Educational Resources Information Center

    Casas, Juan F.; Weigel, Stephanie M.; Crick, Nicki R.; Ostrov, Jamie M.; Woods, Kathleen E.; Yeh, Elizabeth A. Jansen; Huddleston-Casas, Catherine A.

    2006-01-01

    This study investigated early parent-child relationships and how children's use of relational and physical aggression varies with aspects of those relationships during the preschool years. Specifically, parenting styles, parents' use of psychological control, and parents' report of their children's reunion behaviors were assessed. Analyses…

  6. Early life determinants of physical activity in 11 to 12 year olds: cohort study

    PubMed Central

    2008-01-01

    Objective To examine factors in early life (up to age 5 years) that are associated with objectively measured physical activity in 11-12 year olds. Design Prospective cohort study. Setting Avon longitudinal study of parents and children, United Kingdom. Participants Children aged 11-12 years from the Avon longitudinal study of parents and children. Main outcome measure Physical activity levels in counts per minute (cpm) and minutes of moderate to vigorous physical activity for seven days measured with a uniaxial actigraph accelerometer. Results Valid actigraph data, defined as at least three days of physical activity for at least 10 hours a day, were collected from 5451 children. Several factors were associated with physical activity at ages 11-12 years. Regression coefficients are compared with the baseline of “none” for categorical variables: maternal brisk walking during pregnancy (regression coefficient 5.0, 95% confidence interval −8.5 to 18.5; cpm for <1 h/wk and ≥2 h/wk of physical activity 17.7, 5.3 to 30.1), maternal swimming during pregnancy (21.5, 10.9 to 32.1 and cpm for <1 h/wk and ≥2 h/wk of physical activity 24.2, 7.8 to 40.7), parents’ physical activity when the child was aged 21 months (28.5, 15.2 to 41.8 and cpm of physical activity for either parent active and both parents active 33.5, 17.8 to 49.3), and parity assessed during pregnancy (2.9, −7.6 to 13.4 and cpm of physical activity for 1 and ≥2 parity 21.2, 7.1 to 35.3). Conclusions Few factors in early life predicted later physical activity in 11-12 year olds. Parents’ physical activity during pregnancy and early in the child’s life showed a modest association with physical activity of the child at age 11-12 years, suggesting that active parents tend to raise active children. Helping parents to increase their physical activity therefore may promote children’s activity. PMID:18037616

  7. Early Physical Abuse and Later Violent Delinquency: A Prospective Longitudinal Study

    PubMed Central

    Lansford, Jennifer E.; Miller-Johnson, Shari; Berlin, Lisa J.; Dodge, Kenneth A.; Bates, John E.; Pettit, Gregory S.

    2009-01-01

    In this prospective longitudinal study of 574 children followed from age 5 to age 21, the authors examine the links between early physical abuse and violent delinquency and other socially relevant outcomes during late adolescence or early adulthood and the extent to which the child's race and gender moderate these links. Analyses of covariance indicated that individuals who had been physically abused in the first 5 years of life were at greater risk for being arrested as juveniles for violent, nonviolent, and status offenses. Moreover, physically abused youth were less likely to have graduated from high school and more likely to have been fired in the past year, to have been a teen parent, and to have been pregnant or impregnated someone in the past year while not married. These effects were more pronounced for African American than for European American youth and somewhat more pronounced for females than for males. PMID:17631623

  8. Birth order and physical fitness in early adulthood: evidence from Swedish military conscription data.

    PubMed

    Barclay, Kieron; Myrskylä, Mikko

    2014-12-01

    Physical fitness at young adult ages is an important determinant of physical health, cognitive ability, and mortality. However, few studies have addressed the relationship between early life conditions and physical fitness in adulthood. An important potential factor influencing physical fitness is birth order, which prior studies associate with several early- and later-life outcomes such as height and mortality. This is the first study to analyse the association between birth order and physical fitness in late adolescence. We use military conscription data on 218,873 Swedish males born between 1965 and 1977. Physical fitness is measured by a test of maximal working capacity, a measure of cardiovascular fitness closely related to V02max. We use linear regression with sibling fixed effects, meaning a within-family comparison, to eliminate the confounding influence of unobserved factors that vary between siblings. To understand the mechanism we further analyse whether the association between birth order and physical fitness varies by sibship size, parental socioeconomic status, birth cohort or length of the birth interval. We find a strong, negative and monotonic relationship between birth order and physical fitness. For example, third-born children have a maximal working capacity approximately 0.1 (p < 0.000) standard deviations lower than first-born children. The association exists both in small (3 or less children) and large families (4 or more children), in high and low socioeconomic status families, and amongst cohorts born in the 1960s and the 1970s. While in the whole population the birth order effect does not depend on the length of the birth intervals, in two-child families a longer birth interval strengthens the advantage of the first-born. Our results illustrate the importance of birth order for physical fitness, and suggest that the first-born advantage already arises in late adolescence. PMID:25462615

  9. Early Life Emotional, Physical, and Sexual Abuse and the Development of Premenstrual Syndrome: A Longitudinal Study

    PubMed Central

    Whitcomb, Brian W.; Missmer, Stacey A.; Manson, JoAnn E.; Hankinson, Susan E.; Rich-Edwards, Janet W.

    2014-01-01

    Abstract Background: Previous studies have suggested that violence victimization is prevalent among women with premenstrual syndrome (PMS). However, it is unclear whether early life abuse contributes directly to PMS or whether associations are explained by the high prevalence of PMS risk factors including smoking and obesity among women reporting childhood abuse. Methods: We have assessed the relation of early life abuse and the incidence of moderate-to-severe PMS in a study nested within the prospective Nurses' Health Study 2. Participants were aged 27–44 years and free from PMS at baseline, including 1,018 cases developing PMS over 14 years and 2,277 comparison women experiencing minimal menstrual symptoms. History of early life emotional, physical, and sexual abuse was self-reported in 2001. Results: After adjustment for obesity, smoking, and other factors, emotional abuse was strongly related to PMS (pTrend<0.0001); women reporting the highest level of emotional abuse had 2.6 times the risk of PMS as those reporting no emotional abuse (95% confidence interval, 1.7–3.9). Women reporting severe childhood physical abuse had an odds ratio of 2.1 (95% confidence interval, 1.5–2.9; pTrend<0.001) compared with those reporting no physical abuse. Sexual abuse was less strongly associated with risk. Adjustment for childhood social support minimally affected findings. Conclusions: Findings from this large prospective study suggest that early life emotional and physical abuse increase the risk of PMS in the middle-to-late reproductive years. The persistence of associations after control for potential confounders and mediators supports the hypothesis that early life abuse is importantly related to PMS. PMID:25098348

  10. Mechanical loading up-regulates early remodeling signals from osteocytes subjected to physical damage.

    PubMed

    Liu, Chao; Zhang, Xiaoqing; Wu, Michael; You, Lidan

    2015-12-16

    In the mineralized bone matrix, mechanical loading causes micrometer-sized cracks. These cracks trigger targeted remodeling along the micro-crack. Physical damage to osteocytes was shown to be involved in the initiation of this remodeling process. However, the role of subsequent mechanical loading osteocyte response to physical damage is unclear. In this study, we have designed and developed an in vitro cell model to study the impact of mechanical loading on osteocytes with physical damage. Specifically, a system was developed to create sub-cellular physical damage on MLO-Y4 osteocytes in vitro. This model re-created the spatial distribution of non-viable cells and VEGF expression around microdamage as reported in vivo. Using this system, the short term (24h) effects of fluid shear stress in regulation of osteocyte response to physical damage were investigated. We have observed that the mechanical stimuli had an additive effect in terms of COX-2, VEGF mRNA expressions, as well as PGE2, VEGF concentrations in the media. Interestingly, other inflammatory signals such as IL-6 and TNF-α did not change with these stimuli, at this time point. Moreover, fluid shear also had a modulating effect in regulation of osteoclast differentiation by osteocyte with physical damage. These results show that (1) subcellular physical damage upregulates remodeling signals in osteocytes at early time point, (2) mechanical loading substantially upregulates these signals for remodeling in osteocytes with physical damage. PMID:26596719

  11. Early Sexual Intercourse: Prospective Associations with Adolescents Physical Activity and Screen Time

    PubMed Central

    Wijtzes, Anne; van de Bongardt, Daphne; van de Looij-Jansen, Petra; Bannink, Rienke; Raat, Hein

    2016-01-01

    Objectives To assess the prospective associations of physical activity behaviors and screen time with early sexual intercourse initiation (i.e., before 15 years) in a large sample of adolescents. Methods We used two waves of data from the Rotterdam Youth Monitor, a longitudinal study conducted in the Netherlands. The analysis sample consisted of 2,141 adolescents aged 12 to 14 years (mean age at baseline = 12.2 years, SD = 0.43). Physical activity (e.g., sports outside school), screen time (e.g., computer use), and early sexual intercourse initiation were assessed by means of self-report questionnaires. Logistic regression models were tested to assess the associations of physical activity behaviors and screen time (separately and simultaneously) with early sexual intercourse initiation, controlling for confounders (i.e., socio-demographics and substance use). Interaction effects with gender were tested to assess whether these associations differed significantly between boys and girls. Results The only physical activity behavior that was a significant predictor of early sexual intercourse initiation was sports club membership. Adolescent boys and girls who were members of a sports club) were more likely to have had early sex (OR = 2.17; 95% CI = 1.33, 3.56. Significant gender interaction effects indicated that boys who watched TV ≥2 hours/day (OR = 2.00; 95% CI = 1.08, 3.68) and girls who used the computer ≥2 hours/day (OR = 3.92; 95% CI = 1.76, 8.69) were also significantly more likely to have engaged in early sex. Conclusion These findings have implications for professionals in general pediatric healthcare, sexual health educators, policy makers, and parents, who should be aware of these possible prospective links between sports club membership, TV watching (for boys), and computer use (for girls), and early sexual intercourse initiation. However, continued research on determinants of adolescents’ early sexual initiation is needed to further contribute to

  12. Effects of early-onset voluntary exercise on adult physical activity and associated phenotypes in mice.

    PubMed

    Acosta, Wendy; Meek, Thomas H; Schutz, Heidi; Dlugosz, Elizabeth M; Vu, Kim T; Garland, Theodore

    2015-10-01

    The purpose of this study was to evaluate the effects of early-life exercise on adult physical activity (wheel running, home-cage activity), body mass, food consumption, and circulating leptin levels in males from four replicate lines of mice selectively bred for high voluntary wheel running (High Runner or HR) and their four non-selected control (C) lines. Half of the mice were given wheel access shortly after weaning for three consecutive weeks. Wheel access was then removed for 52 days, followed by two weeks of adult wheel access for all mice. A blood sample taken prior to adult wheel testing was analyzed for circulating leptin concentration. Early-life wheel access significantly increased adult voluntary exercise on wheels during the first week of the second period of wheel access, for both HR and C mice, and HR ran more than C mice. During this same time period, activity in the home cages was not affected by early-age wheel access, and did not differ statistically between HR and C mice. Throughout the study, all mice with early wheel access had lower body masses than their sedentary counterparts, and HR mice had lower body masses than C mice. With wheel access, HR mice also ate significantly more than C mice. Early-life wheel access increased plasma leptin levels (adjusted statistically for fat-pad mass as a covariate) in C mice, but decreased them in HR mice. At sacrifice, early-life exercise had no statistically significant effects on visceral fat pad, heart (ventricle), liver or spleen masses (all adjusted statistically for variation in body mass). Results support the hypothesis that early-age exercise in mice can have at least transitory positive effects on adult levels of voluntary exercise, in addition to reducing body mass, and may be relevant for the public policy debates concerning the importance of physical education for children. PMID:26079567

  13. Temperament, Parenting, and South Korean Early Adolescents' Physical Aggression: A Five-Wave Longitudinal Analysis

    ERIC Educational Resources Information Center

    Lee, Julie

    2014-01-01

    Objective: This study examined the growth pattern in physical aggression over a five-year period among South Korean early adolescents and the effects of temperament (anger/frustration and emotion regulation) and parenting (harsh parenting and parental monitoring) on early adolescents' physical aggression. Design: A five-year longitudinal…

  14. Physical activity and sedentary behavior during the early years in Canada: a cross-sectional study

    PubMed Central

    2013-01-01

    Background Physical activity and sedentary behavior habits are established during early childhood, yet only recently has objectively measured data been available on children aged 5 years and younger. This study presents data on the physical activity and sedentary behaviors of Canadian children aged 3–5 years. Methods Data were collected as part of the Canadian Health Measures Survey between 2009 and 2011. A nationally-representative sample (n = 459) of children aged 3–5 years wore Actical accelerometers during their waking hours for 7 consecutive days. Data were collected in 60-sec epochs and respondents with ≥4 valid days were retained for analysis. Parents reported their child’s physical activity and screen time habits in a questionnaire. Results Eighty-four percent of 3–4 year old children met the physical activity guideline of 180 minutes of total physical activity every day while 18% met the screen time target of <1 hour per day. Fourteen percent of 5 year old children met the physical activity guideline of 60 minutes of daily moderate-to-vigorous physical activity (MVPA) while 81% met the screen time target of <2 hours per day. Children aged 3–4 years accumulated an average of 352 min/d of total physical activity and 66 minutes of MVPA while 5 year old children accumulated an average of 342 min/d of total physical activity and 68 minutes of MVPA. Children were sedentary for approximately half of their waking hours and spent an average of 2 hours per day in front of screens. Only 15% of 3–4 year olds and 5% of 5 year olds are meeting both the physical activity and sedentary behavior guidelines. Conclusions Promoting physical activity while reducing sedentary behavior is important at all stages of life. The findings of the present study indicate that there remains significant room for improvement in these behaviors among young Canadian children. PMID:23642258

  15. Views of Adolescent Female Youth on Physical Activity During Early Adolescence

    PubMed Central

    Yungblut, Hope E.; Schinke, Robert J.; McGannon, Kerry R.

    2012-01-01

    Early adolescence is a time when a transition away from sport and physical activity participation is at its highest level among female youth (Hedstrom & Gould, 2004). This has led to the identification of barriers and facilitators of physical activity participation for adolescent females. Consequently there have been calls to overcome barriers and augment facilitators via the creation of gender-relevant programming. Despite these calls and efforts, a gender disparity remains, and a detailed understanding of how girls experience and interpret physical activity within the context of their lives is still lacking. The current project aimed to gain further insight into the foregoing using tenets of Interpretive Phenomenology to further understand the lived physical activity experiences of females during early adolescence, delineating their barriers to participation and the factors enabling participation. Five themes were identified and made into vignettes to facilitate understanding from adolescent females' perspectives: friends or don't know anyone, good or not good enough, fun or not fun; good feeling or gross; and peer support or peer pressure. The physical activity promotion implications for female youth are discussed within the context of these themes. Key points Please provide 3-5 bullet points of the study. Inductive qualitative methodologies can encourage the much-needed voice of female youth in sport and physical activity research. Vignettes serve, not only as a method to illustrate data, but also as a medium to teach contextually relevant information to participants and sport science service providers. The barriers and solutions to female youth engagement in physical activity are best understood through the perspectives of the intended participant. Female youth can serve as central informants in the development and analysis of research projects relating to female youth physical activity. PMID:24149121

  16. The Scaffolded Mind: Higher mental processes are grounded in early experience of the physical world

    PubMed Central

    Williams, Lawrence E.; Huang, Julie Y.; Bargh, John A.

    2009-01-01

    It has long been a staple of psychological theory that early life experiences significantly shape the adult's understanding of and reactions to the social world. Here we consider how early concept development along with evolved motives operating early in life can come to exert a passive, unconscious influence on the human adult's higher-order goal pursuits, judgments, and actions. In particular, we focus on concepts and goal structures specialized for interacting with the physical environment (e.g., distance cues, temperature, cleanliness, and self-protection), which emerge early and automatically as a natural part of human development and evolution. It is proposed that via the process of scaffolding, these early sensorimotor experiences serve as the foundation for the later development of more abstract concepts and goals. Experiments using priming methodologies reveal the extent to which these early concepts serve as the analogical basis for more abstract psychological concepts, such that we come easily and naturally to speak of close relationships, warm personalities, moral purity, and psychological pain. Taken together, this research demonstrates the extent to which such foundational concepts are capable of influencing people's information processing, affective judgments, and goal pursuit, oftentimes outside of their intention or awareness. PMID:20046813

  17. Effects of Online Self-Regulation Activities on Physical Activity Among Pregnant and Early Postpartum Women.

    PubMed

    Kim, Hye Kyung; Niederdeppe, Jeff; Graham, Meredith; Olson, Christine; Gay, Geri

    2015-01-01

    Physical and psychological changes that occur during pregnancy present a unique challenge for women's physical activity. Using a theory-based prospective design, this study examines the effects of pregnant women's (a) physical activity cognitions (self-efficacy, outcome expectancy, and safety beliefs) and (b) online self-regulation activities (goal-setting and self-monitoring) on subsequent changes in their physical activity intentions and behavior during pregnancy and immediately postpartum. The authors used data from three panel surveys administered to pregnant women enrolled in a web-based intervention to promote healthy pregnancy and postpartum weight, as well as log data on their use of self-regulatory features on the intervention website. Perceived self-efficacy and perceived safety of physical activity in pregnancy enhanced subsequent intentions to be physically active. Repeated goal-setting and monitoring of those goals helped to maintain positive intentions during pregnancy, but only repeated self-monitoring transferred positive intentions into actual behavior. Theoretically, this study offers a better understanding of the roles of self-regulation activities in the processes of goal-striving. The authors also discuss practical implications for encouraging physical activity among pregnant and early postpartum women. PMID:26132887

  18. Early age hydration and pozzolanic reaction in natural zeolite blended cements: Reaction kinetics and products by in situ synchrotron X-ray powder diffraction

    SciTech Connect

    Snellings, R.; Mertens, G.; Cizer, O.; Elsen, J.

    2010-12-15

    The in situ early-age hydration and pozzolanic reaction in cements blended with natural zeolites were investigated by time-resolved synchrotron X-ray powder diffraction with Rietveld quantitative phase analysis. Chabazite and Na-, K-, and Ca-exchanged clinoptilolite materials were mixed with Portland cement in a 3:7 weight ratio and hydrated in situ at 40 {sup o}C. The evolution of phase contents showed that the addition of natural zeolites accelerates the onset of C{sub 3}S hydration and precipitation of CH and AFt. Kinetic analysis of the consumption of C{sub 3}S indicates that the enveloping C-S-H layer is thinner and/or less dense in the presence of alkali-exchanged clinoptilolite pozzolans. The zeolite pozzolanic activity is interpreted to depend on the zeolite exchangeable cation content and on the crystallinity. The addition of natural zeolites alters the structural evolution of the C-S-H product. Longer silicate chains and a lower C/S ratio are deduced from the evolution of the C-S-H b-cell parameter.

  19. American Influence on Chinese Physics Study in the Early Twentieth Century

    NASA Astrophysics Data System (ADS)

    Hu, Danian

    2016-01-01

    To save China from the perils she faced in the early twentieth century, the majority of the Chinese seemed to agree that it was necessary to strengthen the country by developing shiye or industry and commerce. For this purpose, they overhauled China's education system and sent a large number of students to study overseas. Many of them enrolled in American colleges, sponsored either by governmental grants or by private funds. As American physics advanced rapidly during the early twentieth century, Chinese physicists studying in top US institutions received first-class professional training. They later went on to become a main driving force in Chinese physics development. The study-in-America programs were apparently more successful than other study-overseas programs. Among other factors, the historical lessons learned from the aborted Chinese Educational Mission in the 1870s, the prevalent and long-time presence of American mission schools in China, and stable public and private funding contributed to their success. American-trained Chinese physicists not only advanced physics study in China but also played leading roles in the development of Chinese science and technology during the twentieth century. This fertile and far-reaching American influence has been embedded in all their accomplishments.

  20. Early physical and motor development of mouse offspring exposed to valproic acid throughout intrauterine development.

    PubMed

    Podgorac, Jelena; Pešić, Vesna; Pavković, Željko; Martać, Ljiljana; Kanazir, Selma; Filipović, Ljupka; Sekulić, Slobodan

    2016-09-15

    Clinical research has identified developmental delay and physical malformations in children prenatally exposed to the antiepileptic drug (AED) valproic acid (VPA). However, the early signs of neurodevelopmental deficits, their evolution during postnatal development and growth, and the dose effects of VPA are not well understood. The present study aimed to examine the influence of maternal exposure to a wide dose range (50, 100, 200 and 400mg/kg/day) of VPA during breeding and gestation on early physical and neuromotor development in mice offspring. Body weight gain, eye opening, the surface righting reflex (SRR) and tail suspension test (TST) were examined in the offspring at postnatal days 5, 10 and 15. We observed that: (1) all tested doses of VPA reduced the body weight of the offspring and the timing of eye opening; (2) offspring exposed to VPA displayed immature forms of righting and required more time to complete the SRR; (3) latency for the first immobilization in the TST is shorter in offspring exposed to higher doses of VPA; however, mice in all groups exposed to VPA exhibited atypical changes in this parameter during the examined period of maturation; (4) irregularities in swinging and curling activities were observed in animals exposed to higher doses of VPA. This study points to delayed somatic development and postponed maturation of the motor system in all of the offspring prenatally exposed to VPA, with stronger effects observed at higher doses. The results implicate that the strategy of continuous monitoring of general health and achievements in motor milestones during the early postnatal development in prenatally VPA-exposed offspring, irrespectively of the dose applied, could help to recognize early developmental irregularities. PMID:27188530

  1. Electron Backscatter Diffraction (EBSD) Analysis and U-Pb Geochronology of the Oldest Lunar Zircon: Constraining Early Lunar Differentiation and Dating Impact-Related Deformation

    NASA Technical Reports Server (NTRS)

    Timms, Nick; Nemchin, Alexander; Grange, Marion; Reddy, Steve; Pidgeon, Bob; Geisler, Thorsten; Meyer, Chuck

    2009-01-01

    The evolution of the early moon was dominated by two processes (i) crystallization of the Lunar Magma Ocean (LMO) and differentiation of potassium-rare earth element-phosphorous-rich residual magma reservoir referred to as KREEP, and (ii) an intense meteorite bombardment referred to as lunar cataclysm . The exact timing of these processes is disputed, and resolution relies on collection and interpretation of precise age data. This study examines the microstructure and geochronology of zircon from lunar impact breccias collected during the Apollo 17 mission. A large zircon clast within lunar breccia 72215,195 shows sector zoning in optical microscopy, cathodoluminescence (CL) imaging and Raman mapping, and indicates that it was a relict fragment of a much larger magmatic grain. Sensitive high resolution ion microprobe (SHRIMP) U-Pb analysis of the zircon shows that U and Th concentration correlate with sector zoning, with darkest CL domains corresponding with high-U and Th (approx.150 and approx.100 ppm respectively), and the brightest-CL sectors containing approx.30-50 ppm U and approx.10-20 ppm Th. This indicates that variations in optical CL and Raman properties correspond to differential accumulation of alpha-radiation damage in each sector. Electron backscatter diffraction (EBSD) mapping shows that the quality of electron backscatter patterns (band contrast) varies with sector zoning, with the poorest quality patterns obtained from high-U and Th, dark-CL zones. EBSD mapping also reveals a deformation microstructure that is cryptic in optical, CL and Raman imaging. Two orthogonal sets of straight discrete and gradational low-angle boundaries accommodate approx.12 misorientation across the grain. The deformation bands are parallel to the crystallographic {a}-planes of the zircon, have misorientation axes parallel to the c-axis, and are geometrically consistent with formation by dislocation creep associated with <100>{010} slip. The deformation bands are unlike

  2. MAOA uVNTR and Early Physical Discipline Interact to Influence Delinquent Behavior

    PubMed Central

    Edwards, Alexis C.; Dodge, Kenneth A.; Latendresse, Shawn J.; Lansford, Jennifer E.; Bates, John E.; Pettit, Gregory S.; Budde, John P.; Goate, Alison M.; Dick, Danielle M.

    2011-01-01

    Background A functional polymorphism in the promoter region of the monoamine oxidizing gene monoamine oxidase A (MAOA) has been associated with behavioral sensitivity to adverse environmental conditions in multiple studies (e.g., Caspi et al. 2002, Kim-Cohen et al. 2006). The present study investigates the effects of genotype and early physical discipline on externalizing behavior. We expand on the current literature in our assessment of externalizing, incorporating information across multiple reporters and over a broad developmental time period, and in our understanding of environmental risk. Method This study uses data from the Child Development Project, an ongoing longitudinal study following a community sample of children beginning at age 5. Physical discipline before age 6 was quantified using a subset of questions from the Conflict Tactics Scale (Straus 1979). Externalizing behavior was assessed in the male, European-American sub-sample (N=250) by parent, teacher, and self report using Achenbach’s Child Behavior Checklist, Teacher Report Form, and Youth Self-Report (Achenbach 1991), at 17 time points from ages 6 to 22. Regression analyses tested the influence of genotype, physical discipline, and their interaction on externalizing behavior, and its subscales, delinquency and aggression. Results We found a significant interaction effect between genotype and physical discipline on levels of delinquent behavior. Similar trends were observed for aggression and overall externalizing behavior, although these did not reach statistical significance. Main effects of physical discipline held for all outcome variables, and no main effects held for genotype. Conclusion The adverse consequences of physical discipline on forms of externalizing behavior are exacerbated by an underlying biological risk conferred by MAOA genotype. PMID:19951362

  3. Predicting Early Adolescents' Academic Achievement, Social Competence, and Physical Health from Parenting, Ego Resilience, and Engagement Coping

    ERIC Educational Resources Information Center

    Swanson, Jodi; Valiente, Carlos; Lemery-Chalfant, Kathryn; O'Brien, T. Caitlin

    2011-01-01

    This study examined ego resilience and engagement coping as mediators of the relationships between supportive and controlling parenting practices and early adolescents' academic achievement, social competence, and physical health. Participants were 240 predominantly Mexican American early adolescents, their parents, and their teachers. There were…

  4. Early motor skill competence as a mediator of child and adult physical activity

    PubMed Central

    Loprinzi, Paul D.; Davis, Robert E.; Fu, Yang-Chieh

    2015-01-01

    Objective: In order to effectively promote physical activity (PA) during childhood, and across the lifespan, a better understanding of the role of early motor skill development on child and adult PA is needed. Methods: Here, we propose a conceptual model delineating the hypothesized influence of motor skill development on child and adult PA, while providing an overview of the current empirical research related to this model. Results: There is consistent and emerging evidence showing that adequate motor skill competence, particularly locomotor and gross motor skills, is associated with increased PA levels during the preschool, child, and adolescent years, with early motor skill development also influencing enjoyment of PA as well as long-term PA and motor skill performance. The physical education setting appears to be a well-suited environment for motor skill development. Conclusion: Employing appropriate strategies to target motor skill development across the childhood years is of paramount interest in helping shape children's PA behavior, their experiences related to PA, as well as maintain their PA. PMID:26844157

  5. Early maternal and paternal bonding, childhood physical abuse and adult psychopathic personality

    PubMed Central

    Gao, Y.; Raine, A.; Chan, F.; Venables, P. H.; Mednick, S. A.

    2013-01-01

    Background A significant gap in the literature on risk factors for psychopathy is the relative lack of research on parental bonding. Method This study examines the cross-sectional relationship between maternal and paternal bonding, childhood physical abuse and psychopathic personality at age 28 years in a community sample of 333 males and females. It also assesses prospectively whether children separated from their parents in the first 3 years of life are more likely to have a psychopathic-like personality 25 years later. Results Hierarchical regression analyses indicated that: (1) poor parental bonding (lack of maternal care and low paternal overprotection) and childhood physical abuse were both associated with a psychopathic personality; (2) parental bonding was significantly associated with psychopathic personality after taking into account sex, social adversity, ethnicity and abuse; (3) those separated from parents in the first 3 years of life were particularly characterized by low parental bonding and a psychopathic personality in adulthood; and (4) the deviant behavior factor of psychopathy was more related to lack of maternal care whereas the emotional detachment factor was related to both lack of maternal care and paternal overprotection. Conclusions Findings draw attention to the importance of different components of early bonding in relation to adult psychopathy, and may have potential implications for early intervention and prevention of psychopathy. PMID:20441692

  6. News Almost dry but never dull: ASE 2014 EuroPhysicsFun shows physics to Europe Institute of Physics for Africa (IOPfA) South Sudan Report October 2013 Celebrating the centenary of x-ray diffraction The Niels Bohr Institute—an EPS Historical Site Nordic Research Symposium on Science Education (NFSUN) 2014: inquiry-based science education in technology-rich environments Physics World Cup 2013

    NASA Astrophysics Data System (ADS)

    2014-03-01

    Almost dry but never dull: ASE 2014 EuroPhysicsFun shows physics to Europe Institute of Physics for Africa (IOPfA) South Sudan Report October 2013 Celebrating the centenary of x-ray diffraction The Niels Bohr Institute—an EPS Historical Site Nordic Research Symposium on Science Education (NFSUN) 2014: inquiry-based science education in technology-rich environments Physics World Cup 2013

  7. Bridging Empirical and Physical Approaches for Landslide Monitoring and Early Warning

    NASA Technical Reports Server (NTRS)

    Kirschbaum, Dalia; Peters-Lidard, Christa; Adler, Robert; Kumar, Sujay; Harrison, Ken

    2011-01-01

    Rainfall-triggered landslides typically occur and are evaluated at local scales, using slope-stability models to calculate coincident changes in driving and resisting forces at the hillslope level in order to anticipate slope failures. Over larger areas, detailed high resolution landslide modeling is often infeasible due to difficulties in quantifying the complex interaction between rainfall infiltration and surface materials as well as the dearth of available in situ soil and rainfall estimates and accurate landslide validation data. This presentation will discuss how satellite precipitation and surface information can be applied within a landslide hazard assessment framework to improve landslide monitoring and early warning by considering two disparate approaches to landslide hazard assessment: an empirical landslide forecasting algorithm and a physical slope-stability model. The goal of this research is to advance near real-time landslide hazard assessment and early warning at larger spatial scales. This is done by employing high resolution surface and precipitation information within a probabilistic framework to provide more physically-based grounding to empirical landslide triggering thresholds. The empirical landslide forecasting tool, running in near real-time at http://trmm.nasa.gov, considers potential landslide activity at the global scale and relies on Tropical Rainfall Measuring Mission (TRMM) precipitation data and surface products to provide a near real-time picture of where landslides may be triggered. The physical approach considers how rainfall infiltration on a hillslope affects the in situ hydro-mechanical processes that may lead to slope failure. Evaluation of these empirical and physical approaches are performed within the Land Information System (LIS), a high performance land surface model processing and data assimilation system developed within the Hydrological Sciences Branch at NASA's Goddard Space Flight Center. LIS provides the

  8. Physical and sexual abuse in childhood as predictors of early onset cardiovascular events in women

    PubMed Central

    Rich-Edwards, J.W.; Mason, S.; Rexrode, K.; Spiegelman, D.; Hibert, E.; Kawachi, I.; Jun, H.J.; Wright, R.J.

    2012-01-01

    Background Although child abuse is widespread and has been associated with cardiovascular disease (CVD) risk factors, its association with CVD events is not established. Methods and Results We examined associations of child abuse with CVD events among 66,798 women in the Nurses’ Health Study 2. Proportional hazards models estimated hazard ratios (HR) and 95% confidence intervals (CI) for myocardial infarction (n=262), stroke (n=251), and total CVD (n=513). Severe physical abuse was reported by 9% and forced sex by 11% of participants. Adjusting for age, race, childhood body type, parental education and family CVD history, the HR for CVD events was 0.91 (95% CI: 0.70–1.17) for mild physical abuse, 1.02 (0.82–1.26) for moderate physical abuse, and 1.46 (1.11–1.92) for severe physical abuse compared to none. Compared to women without childhood sexual abuse, the HR was 1.10 (0.88–1.35) for unwanted sexual touching, and 1.56 (1.23–1.99) for forced sex. After adjustment for adult lifestyle and medical risk factors, the HR for severe physical abuse was 1.13 (0.85–1.51) and that for forced sex was 1.25 (0.98–1.60); these intermediates accounted for much of the association of severe child abuse with CVD. Associations were similar for retrospectively and prospectively reported events. Women with abuse were less likely to release medical records. The associations were stronger for unconfirmed self-reported events than endpoints which were corroborated with additional information or medical record review. Conclusions Severe child abuse is a prevalent risk for early adult CVD that is partially mediated by preventable risk factors. PMID:22787111

  9. An investigation of the early factors which influence women's career choices in physical science and technology

    NASA Astrophysics Data System (ADS)

    Payne, Anneliese

    The composition of the workforce has begun to undergo a change. The U.S. Department of Labor estimates that women, minorities, and immigrants will constitute 80 percent of the additions to the labor force between 1987 and the year 2000 (Oakes, 1990). The National Science Foundation projects that the United States may have a shortfall of 400,000 scientists and over 250,000 engineers by the year 2006 (Argonne, 1990). Since women are among those who are significantly underrepresented among individuals preparing for a career in science, thirty women who are currently pursuing a successful career in physical science and technology were interviewed. This study determined participants' perceptions of the factors that first influenced an early interest in physical science and technology. The investigation included perceptions regarding: (1) whether certain identifiable events or experiences influenced the decision to pursue science as a career and what those events and experiences were; (2) at what age these events occurred; (3) whether an adult(s) was influential and which adult(s) it was; and (4) identification of where these events and experiences occurred. The interview technique was selected as the best research method for collecting the qualitative and demographic data needed for this study. The results represent the participants' recollections of out-of-school and in-school activities, family, friends and teacher support, self-image during the formative years, parents as the most important factor which influenced an interest in physical science, and major obstacles that had to be overcome by the participants in order to pursue successful careers in physical science and technology. Also included is participants' advice to parents and teachers who want to encourage females to pursue a career in physical science and technology.

  10. Effects of Perinatal HIV Infection and Early Institutional Rearing on Physical and Cognitive Development of Children in Ukraine

    ERIC Educational Resources Information Center

    Dobrova-Krol, Natasha A.; van IJzendoorn, Marinus H.; Bakermans-Kranenburg, Marian J.; Juffer, Femmie

    2010-01-01

    To study the effects of perinatal HIV-1 infection and early institutional rearing on the physical and cognitive development of children, 64 Ukrainian uninfected and HIV-infected institutionalized and family-reared children were examined (mean age = 50.9 months). Both HIV infection and institutional care were related to delays in physical and…

  11. Immersion francaise precoce: Education physique 1-7 (Early French Immersion: Physical Education for Grades 1-7).

    ERIC Educational Resources Information Center

    Burt, Andy; And Others

    This curriculum guide for physical education is intended for use in grades 1-7 in the early French immersion program. It is a translation of the regular physical education program and a compilation of references and supplementary teaching material. It is noted that because of the comparative lack of references in French, much of the reference…

  12. Early temporal negativity is sensitive to perceived (rather than physical) facial identity.

    PubMed

    Faerber, Stella J; Kaufmann, Jürgen M; Schweinberger, Stefan R

    2015-08-01

    Increased early negativity to repeated faces over inferior temporal regions around 200-300 ms has been related to the reactivation of mental representations of individual identities of familiar faces. Since this modulation is larger for same-image (compared to different-image) repetitions of a familiar face, it is debated whether it reflects physical stimulus similarity between prime and target, or reactivation of perceived representations of identity. In Experiment 1 participants performed a four-choice identification task on famous target faces, which were always preceded by the same average face. This average face served as prime stimulus. Crucially, by adapting participants to specific anti-faces, we induced different illusory facial identities (cf. Leopold, D.A., O'Toole, A.J., Vetter, T., Blanz, V., 2001. Prototype-referenced shape encoding revealed by high-level after effects. Nature Neuroscience 4 (1), 89-94) in the same physical prime. Importantly, temporal ERPs (~ 155-235 ms) were significantly more negative for "Primed" than for "Unprimed" trials. In Experiment 2, we determined whether this effect was due to the encoding of shape information, by using anti-shape adaptors with constant average reflectance information. Priming by these anti-shape adapted average primes did not elicit a similar temporal ERP modulation. We conclude that these early temporal ERP modulations evoked by a combination of anti-face adaptation and immediate-repetition priming represent a neural correlate of the activation of mental representations of individual familiar faces. These identity specific representations can be triggered even by physically identical prime stimuli, when preceded by corresponding anti-face adaptation. PMID:26013406

  13. Maternal prenatal smoking, parental antisocial behavior, and early childhood physical aggression.

    PubMed

    Huijbregts, Stephan C J; Séguin, Jean R; Zoccolillo, Mark; Boivin, Michel; Tremblay, Richard E

    2008-01-01

    This study investigated joint effects of maternal prenatal smoking and parental history of antisocial behavior on physical aggression between ages 17 and 42 months in a population sample of children born in Québec (N = 1,745). An analysis of variance (ANOVA) showed significant main effects of maternal prenatal smoking and a significant interaction between maternal prenatal smoking and mother's history of antisocial behavior in the prediction of children's probability to display high and rising physical aggression. The interaction indicated that the effects of heavy smoking during pregnancy (> or =10 cigarettes/day) were greater when the mother also had a serious history of antisocial behavior. The effects remained significant after the introduction of control variables (e.g., hostile-reactive parenting, family functioning, parental separation/divorce, family income, and maternal education). Another significant interaction not accounted for by control variables was observed for maternal prenatal smoking and family income, indicating more serious effects of maternal prenatal smoking under relatively low-income, conditions. Both interactions indicate critical adversities that, in combination with maternal prenatal smoking, have supra-additive effects on (the development of) physical aggression during early childhood. These findings may have implications for the selection of intervention targets and strategies. PMID:18423088

  14. Early reduction in toe flexor strength is associated with physical activity in elderly men

    PubMed Central

    Suwa, Masataka; Imoto, Takayuki; Kida, Akira; Yokochi, Takashi

    2016-01-01

    [Purpose] To compare the toe flexor, hand grip and knee extensor strengths of young and elderly men, and to examine the association between toe flexor strength and physical activity or inactivity levels. [Subjects and Methods] Young (n=155, 18–23 years) and elderly (n=60, 65–88 years) men participated in this study. Toe flexor, hand grip, and knee extensor strength were measured. Physical activity (time spent standing/walking per day) and inactivity (time spent sitting per day) were assessed using a self-administered questionnaire. [Results] Toe flexor, hand grip, and knee extensor strength of the elderly men were significantly lower than those of the young men. Standing/walking and sitting times of the elderly men were lower than those of the young men. Toe flexor strength correlated with hand grip and knee extensor strength in both groups. In elderly men, toe flexor strength correlated with standing/walking time. In comparison to the young men’s mean values, toe flexor strength was significantly lower than knee extensor and hand grip strength in the elderly group. [Conclusion] The results suggest that age-related reduction in toe flexor strength is greater than those of hand grip and knee extensor strengths. An early loss of toe flexor strength is likely associated with reduced physical activity in elderly men. PMID:27313353

  15. Continuity and Change in Social and Physical Aggression from Middle Childhood through Early Adolescence

    PubMed Central

    Underwood, Marion K.; Beron, Kurt J.; Rosen, Lisa H.

    2009-01-01

    For a sample followed from age 9–13 (N=281), this investigation examined developmental trajectories for social and physical aggression as measured by teacher ratings. Trajectories for both forms of aggression were estimated first separately, then jointly. Mean levels of both social and physical aggression decreased over time for the overall sample, but with high variability of individual trajectories. Subgroups followed high trajectories for both social and physical aggression. Joint estimation yielded six trajectories: low stable, low increasers, medium increasers, medium desisters, high desisters, and high increasers. Membership in the high increaser group was predicted by male gender, unmarried parents, African American ethnicity, and maternal authoritarian and permissive parenting. Permissive parenting also predicted membership in the medium increaser group. This is one of the first studies to examine social aggression longitudinally across this developmental period. Though the results challenge the claim that social aggression is at its peak in early adolescence, the findings emphasize the importance of considering different developmental trajectories in trying to understand origins and outcomes of aggression. PMID:19685551

  16. Application of radiation physics to improve dosimetry in early breast cancer radiotherapy

    SciTech Connect

    Donovan, Ellen Mary

    2005-07-15

    Radiotherapy for early breast cancer has been shown to be a highly effective treatment in a number of long term studies. The radiation dose uniformity of the current standard treatments is often poor, however, with dose variations across the breast much higher than those recommended in international guidelines. This work aimed to explore methods for improving this aspect of the radiation dosimetry of early breast cancer radiotherapy. An experimental method was validated by applying it to computed tomography data from 14 patients with a variety of breast shapes and sizes. The volume of the breast receiving the desired dose levels increased by a mean of 6.9% (range -0.8% to 15.9%) and this benefit was shown to increase with breast volume. The quality of reference images in the verification of treatments was improved by introducing differential filtering to the imaging beams on a radiotherapy simulator. The positive results from the first two studies were applied in a clinical trial (which used the experimental technique). The unique set of data from the trial was analyzed and confirmation of dosimetric improvement, and the increased benefit, for larger breasted women were found. In addition, an analysis of the position of high doses showed these occurred in the upper or lower third of the breast and affected 46% and 30% of patients, respectively, with standard treatment but only 1% of patients with the improved method. Other published methods for improving breast dosimetry were explored by building a simple physical model and carrying out a comparative planning study. The physical model was shown to be effective in predicting the dosimetric consequences of each method. The planning study showed that there was little difference between the methods generally but dosimetric improvement could be increased for larger breast volumes by an appropriate choice of technique. A final study explored how breathing control could be used to reduce cardiac doses in patients with

  17. Diffraction radiation generators

    NASA Astrophysics Data System (ADS)

    Shestopalov, Viktor P.; Vertii, Aleksei A.; Ermak, Gennadii P.; Skrynnik, Boris K.; Khlopov, Grigorii I.; Tsvyk, Aleksei I.

    Research in the field of diffraction radiation generators (DRG) conducted at the Radio Physics and electronics Institute of the Ukranian Academy of Sciences over the past 25 years is reviewed. The effect of diffraction radiation is analyzed in detail, and various operating regimes of DRGs are discussed. The discussion then focuses on the principal requirements for the design of packaged DRGs and their principal parameters. Finally, applications of DRGs in various fields of science and technology are reviewed, including such applications as DRG spectroscopy, diagnostics of plasma, biological specimens, and vibration, and DRG radar systems.

  18. Comparison of fluvial suspended-sediment concentrations and particle-size distributions measured with in-stream laser diffraction and in physical samples

    USGS Publications Warehouse

    Czuba, Jonathan A.; Straub, Timothy D.; Curran, Christopher A.; Landers, Mark N.; Domanski, Marian M.

    2014-01-01

    Laser-diffraction technology, recently adapted for in-stream measurement of fluvial suspended-sediment concentrations (SSCs) and particle-size distributions (PSDs), was tested with a streamlined (SL), isokinetic version of the Laser In-Situ Scattering and Transmissometry (LISST) for measuring volumetric SSCs and PSDs ranging from 1.8-415 µm in 32 log-spaced size classes. Measured SSCs and PSDs from the LISST-SL were compared to a suite of 22 datasets (262 samples in all) of concurrent suspended-sediment and streamflow measurements using a physical sampler and acoustic Doppler current profiler collected during 2010-12 at 16 U.S. Geological Survey streamflow-gaging stations in Illinois and Washington (basin areas: 38 – 69,264 km2). An unrealistically low computed effective density (mass SSC / volumetric SSC) of 1.24 g/ml (95% confidence interval: 1.05-1.45 g/ml) provided the best-fit value (R2 = 0.95; RMSE = 143 mg/L) for converting volumetric SSC to mass SSC for over 2 orders of magnitude of SSC (12-2,170 mg/L; covering a substantial range of SSC that can be measured by the LISST-SL) despite being substantially lower than the sediment particle density of 2.67 g/ml (range: 2.56-2.87 g/ml, 23 samples). The PSDs measured by the LISST-SL were in good agreement with those derived from physical samples over the LISST-SL's measureable size range. Technical and operational limitations of the LISST-SL are provided to facilitate the collection of more accurate data in the future. Additionally, the spatial and temporal variability of SSC and PSD measured by the LISST-SL is briefly described to motivate its potential for advancing our understanding of suspended-sediment transport by rivers.

  19. Comparison of fluvial suspended-sediment concentrations and particle-size distributions measured with in-stream laser diffraction and in physical samples

    NASA Astrophysics Data System (ADS)

    Czuba, Jonathan A.; Straub, Timothy D.; Curran, Christopher A.; Landers, Mark N.; Domanski, Marian M.

    2015-01-01

    Laser-diffraction technology, recently adapted for in-stream measurement of fluvial suspended-sediment concentrations (SSCs) and particle-size distributions (PSDs), was tested with a streamlined (SL), isokinetic version of the Laser In Situ Scattering and Transmissometry (LISST) for measuring volumetric SSCs and PSDs ranging from 1.8 to 415 μm in 32 log-spaced size classes. Measured SSCs and PSDs from the LISST-SL were compared to a suite of 22 data sets (262 samples in all) of concurrent suspended-sediment and streamflow measurements using a physical sampler and acoustic Doppler current profiler collected during 2010-2012 at 16 U.S. Geological Survey streamflow-gaging stations in Illinois and Washington (basin areas: 38-69,264 km2). An unrealistically low computed effective density (mass SSC/volumetric SSC) of 1.24 g/mL (95% confidence interval: 1.05-1.45 g/mL) provided the best-fit value (R2 = 0.95; RMSE = 143 mg/L) for converting volumetric SSC to mass SSC for over two orders of magnitude of SSC (12-2,170 mg/L; covering a substantial range of SSC that can be measured by the LISST-SL) despite being substantially lower than the sediment particle density of 2.67 g/mL (range: 2.56-2.87 g/mL, 23 samples). The PSDs measured by the LISST-SL were in good agreement with those derived from physical samples over the LISST-SL's measureable size range. Technical and operational limitations of the LISST-SL are provided to facilitate the collection of more accurate data in the future. Additionally, the spatial and temporal variability of SSC and PSD measured by the LISST-SL is briefly described to motivate its potential for advancing our understanding of suspended-sediment transport by rivers.

  20. The influence of the neighborhood physical environment on early child health and development: A review and call for research.

    PubMed

    Christian, Hayley; Zubrick, Stephen R; Foster, Sarah; Giles-Corti, Billie; Bull, Fiona; Wood, Lisa; Knuiman, Matthew; Brinkman, Sally; Houghton, Stephen; Boruff, Bryan

    2015-05-01

    This review examines evidence of the association between the neighborhood built environment, green spaces and outdoor home area, and early (0-7 years) child health and development. There was evidence that the presence of child relevant neighborhood destinations and services were positively associated with early child development domains of physical health and wellbeing and social competence. Parents׳ perceptions of neighborhood safety were positively associated with children׳s social-emotional development and general health. Population representative studies using objective measures of the built environment and valid measures of early child development are warranted to understand the impact of the built environment on early child health and development. PMID:25744220

  1. Gravitational waves: A probe to the physics in the early universe

    NASA Astrophysics Data System (ADS)

    Huang, Qing-Guo

    2015-10-01

    Gravitational waves can escape from the big bang and can be taken as a probe to the physics, in particular the inflation, in the early universe. Planck scale is a fundamental scale for quantum theory of gravity. Requiring the excursion distance of inflaton in the field space during inflation yields an upper bound on the tensor-to-scalar ratio. For example, r < 7 × 10-4 for ns = 0.9645. In the typical inflationary scenario, we predict 1 - 2/N < ns < 1 and - 2/N2 < α s < 0 which are consistent with Planck data released in 2015 quite well. Subtracting the contribution of thermal dust measured by Planck, BICEP2 data implies r ≲ 0.08 which is the tightest bound on the tensor-to-scalar ratio from current experiments.

  2. Two-dimensional models of early-type fast rotating stars: new challenges in stellar physics

    NASA Astrophysics Data System (ADS)

    Rieutord, M.; Espinosa Lara, F.

    2013-12-01

    Two-dimensional models of rapidly rotating stars are already unavoidable for the interpretation of interferometric or asteroseismic data of this kind of stars. When combined with time evolution, they will allow the including of a more accurate physics for the computation of element transport and the determination of surface abundances. In addition, modeling the evolution of rotation will improve gyrochronology. Presently, two-dimensional ESTER models predict the structure and the large-scale flows (differential rotation and meridional circulation) of stars with mass larger than 1.7 M⊙ at any rotation rate. Main sequence evolution can be mimicked by varying the hydrogen content of the convective core. Models have been successfully tested on half a dozen of nearby fast rotating stars observed with optical or infra-red interferometers. They are now the right tool to investigate the oscillation spectrum of early-type fast rotators.

  3. Dust Plate, Retina, Photograph: Imaging on Experimental Surfaces in Early Nineteenth-Century Physics.

    PubMed

    Ramalingam, Chitra

    2015-09-01

    This article explores the entangled histories of three imaging techniques in early nineteenth-century British physical science, techniques in which a dynamic event (such as a sound vibration or an electric spark) was made to leave behind a fixed trace on a sensitive surface. Three categories of "sensitive surface" are examined in turn: first, a metal plate covered in fine dust; second, the retina of the human eye; and finally, a surface covered with a light-sensitive chemical emulsion (a photographic plate). For physicists Michael Faraday and Charles Wheatstone, and photographic pioneer William Henry Fox Talbot, transient phenomena could be studied through careful observation and manipulation of the patterns wrought on these different surfaces, and through an understanding of how the imaging process unfolded through time. This exposes the often-ignored materiality and temporality of epistemic practices around nineteenth-century scientific images said to be "drawn by nature." PMID:26256503

  4. The Contribution of Former Work-Related Activity Levels to Predict Physical Activity and Sedentary Time during Early Retirement: Moderating Role of Educational Level and Physical Functioning

    PubMed Central

    Van Dyck, Delfien; Cardon, Greet; Deforche, Benedicte; De Bourdeaudhuij, Ilse

    2015-01-01

    Background The transition to retirement introduces a decline in total physical activity and an increase in TV viewing time. Nonetheless, as more time becomes available, early retirement is an ideal stage to implement health interventions. Therefore, knowledge on specific determinants of physical activity and sedentary time is needed. Former work-related physical activity has been proposed as a potential determinant, but concrete evidence is lacking. The aim of this study was to examine if former work-related sitting, standing, walking or vigorous activities predict physical activity and sedentary time during early retirement. Additionally, moderating effects of educational level and physical functioning were examined. Methods In total, 392 recently retired Belgian adults (>6 months, <5 years) completed the International Physical Activity Questionnaire, the SF-36 Health Survey and a questionnaire on sociodemographics and former work-related activities. Generalized linear regression analyses were conducted in R. Moderating effects were examined by adding cross-products to the models. Results More former work-related sitting was predictive of more screen time during retirement. Lower levels of former work-related vigorous activities and higher levels of former work-related walking were associated with respectively more cycling for transport and more walking for transport during retirement. None of the predictors significantly explained passive transportation, cycling and walking for recreation, and leisure-time moderate-to-vigorous physical activity during retirement. Several moderating effects were found, but the direction of the interactions was not univocal. Conclusions Former-work related behaviors are of limited importance to explain physical activity during early retirement, so future studies should focus on other individual, social and environmental determinants. Nonetheless, adults who previously had a sedentary job had higher levels of screen time during

  5. Early Adolescent Sexual Initiation and Physical/Psychological Symptoms: A Comparative Analysis of Five Nations

    PubMed Central

    Farhat, Tilda; Halpern, Carolyn Tucker; Godeau, Emmanuelle; Gabhainn, Saoirse Nic

    2010-01-01

    Although most people in developed countries experience sexual initiation during adolescence, little is known about inter-country variability in the psychosocial correlates of early initiation. Population-based samples of 15-year-olds (n = 6,111, 52% female) who participated in the Health Behaviors in School-Aged Children Study (Finland, Scotland, France and Poland, 1997/1998) or the National Longitudinal Study of Adolescent Health (United States, 1996) self-reported sexual intercourse experience and physical (headaches, trouble sleeping) or psychological (unhappiness, loneliness, sadness, moodiness) symptoms. Analyses were conducted stratified by gender. Sexual initiation prevalence and symptoms scores varied significantly across nations. In adjusted models, sexual initiation was not related to symptoms among boys in any nation, but significantly positively related to symptoms among girls in Poland and the US. Results support variability by gender and nation in the relationship between adolescents’ sexual initiation and physical/psychological symptoms. Empirically investigating specific features of national contexts that generate these differences should be explored further. PMID:20333456

  6. Towards a physical classification of early-type galaxies. Profile of a key programme.

    NASA Astrophysics Data System (ADS)

    Bender, R.; Capaccioli, M.; Macchetto, F.; Nieto, J.-L.

    1989-03-01

    Hubble was the first who succeeded in classifying galaxies within a scheme of some physical meaning. Although it soon became clear that Hubble's tuning fork does not represent an evolutionary sequence, this essential diagram has proven to be a powerful tool especially for the understanding of late-type galaxies. On the other hand, the "early-type" sequence of elliptical (E) and SO galaxies is less satisfying, because it does not seem to reflect a unique sequence of physical properties. The SO class, although conceived to bridge the gap between disk- and disk-Iess galaxies, has often been abused to host ellipticals exhibiting peculiarities incompatible with their definition as structureless objects. For the elliptical galaxies themselves, "ellipticity" has been found to be essentially meaningless with regard to their angular momentum properties, and shows Iittle, if any, correlation with other global parameters. This fact became apparent after the first stellar kinematical measurements of luminous ellipticals (Bertola and Capaccioli 1975, IIlingworth 1977); E galaxies are not necessarily f1attened by rotation and may have anisotropie velocity dispersions (Binney 1978).

  7. Similarities and differences in physical self-concept of males and females during late adolescence and early adulthood.

    PubMed

    Cağlar, Emine

    2009-01-01

    The purpose of this study was to examine age and sex differences in physical self-concept of Turkish late adolescents and early adults. A total of 715 high school and 1,125 university students voluntarily participated and were administered the Physical Self-Description Questionnaire. The findings indicate significant sex and age differences on multiple dimensions of physical self, and that males and high school students scored higher on almost all subscales of physical self. However, analysis did not reveal any significant age and sex interactions on physical self. In conclusion, males and females differ from each other on how they perceived themselves on the multiple dimensions of physical self, and developmental age changes were evident in physical self. PMID:19764275

  8. Early-Life Adversity and Physical and Emotional Health Across the Lifespan: A Neuroimmune Network Hypothesis.

    PubMed

    Nusslock, Robin; Miller, Gregory E

    2016-07-01

    Children who experience chronic stressors are vulnerable to emotional and physical health problems across the lifespan. This phenomenon raises questions for scientists and clinicians alike. How does adversity get under the skin of the developing child? Through what mechanisms does it confer vulnerability to a heterogeneous set of mental and physical illnesses? And how does it instantiate risk across different life stages, engendering vulnerability to conditions that develop shortly after stressor exposure-like depression-and conditions that manifest decades later, like heart disease? Although answers to these questions have started to emerge, research has typically focused on single diseases or organ systems. To understand the plethora of health problems associated with childhood adversity, we argue that the field needs a second generation of research that recognizes multidirectional transactions among biological systems. To help facilitate this process, we propose a neuroimmune network hypothesis as a heuristic framework for organizing knowledge from disparate literatures and as a springboard for generating integrative research. Drawing on existing data, we argue that early-life adversity amplifies crosstalk between peripheral inflammation and neural circuitries subserving threat-related, reward-related, and executive control-related processes. This crosstalk results in chronic low-grade inflammation, thereby contributing to adiposity, insulin resistance, and other predisease states. In the brain, inflammatory mediators act on cortico-amygdala threat and cortico-basal ganglia reward, circuitries in a manner that predisposes individuals to self-medicating behaviors like smoking, drug use, and consumption of high-fat diets. Acting in concert with inflammation, these behaviors accelerate the pathogenesis of emotional and physical health problems. PMID:26166230

  9. Physical Environmental Adversity and the Protective Role of Maternal Monitoring in Relation to Early Child Conduct Problems

    PubMed Central

    Supplee, Lauren H.; Unikel, Emily B.; Shaw, Daniel S.

    2007-01-01

    Research on the development of externalizing behaviors during early childhood has focused on child and parenting factors. Fewer studies have investigated effects of aversive features of the micro-level physical environment, such as overcrowding and chaos in the home, and the macro-level environment, such as neighborhood quality. This study extends research on physical environmental factors by examining their association with children’s early externalizing behaviors, and exploring how maternal monitoring may serve as a protective factor in such contexts. 120 male toddlers at high risk for developing early externalizing behaviors were followed from ages 2 to 5 years. Direct longitudinal associations were found for micro-level environmental factors beginning at age 2 and for neighborhood risk beginning at age 3. Maternal monitoring served as a protective factor for child externalizing behaviors in the context of neighborhood risk. Implications for prevention research and the development of early externalizing behaviors are discussed. PMID:18311323

  10. Mgat5 modulates the effect of early life stress on adult behavior and physical health in mice.

    PubMed

    Feldcamp, Laura; Doucet, Jean-Sebastien; Pawling, Judy; Fadel, Marc P; Fletcher, Paul J; Maunder, Robert; Dennis, James W; Wong, Albert H C

    2016-10-01

    Psychosocial adversity in early life increases the likelihood of mental and physical illness, but the underlying mechanisms are poorly understood. Mgat5 is an N-acetylglucosaminyltransferase in the Golgi pathway that remodels the N-glycans of glycoproteins at the cell surface. Mice lacking Mgat5 display conditional phenotypes in behaviour, immunity, metabolism, aging and cancer susceptibility. Here we investigated potential gene-environment interactions between Mgat5 and early life adversity on behaviour and physiological measures of physical health. Mgat5(-/-) mutant and Mgat5(+/+) wild-type C57Bl/6 littermates were subject to maternal separation or foster rearing as an early life stressor, in comparison to control mice reared normally. We found an interaction between Mgat5 genotype and maternal rearing condition in which Mgat5(-/-) mice subjected to early life stress had lower glucose levels and higher bone density. Mgat5(-/-) genotype was also associated with less immobility in the forced swim test and greater sucrose consumption, consistent with a less depression-like phenotype. Cortical neuron dendrite spine density and branching was altered by Mgat5 deletion as well. In general, Mgat5 genotype affects both behaviour and physical outcomes in response to early life stress, suggesting some shared pathways for both in this model. These results provide a starting point for studying the mechanisms by which protein N-glycosylation mediates the effects of early life adversity. PMID:27329152

  11. Diffraction-based optical correlator

    NASA Technical Reports Server (NTRS)

    Spremo, Stevan M. (Inventor); Fuhr, Peter L. (Inventor); Schipper, John F. (Inventor)

    2005-01-01

    Method and system for wavelength-based processing of a light beam. A light beam, produced at a chemical or physical reaction site and having at least first and second wavelengths, ?1 and ?2, is received and diffracted at a first diffraction grating to provide first and second diffracted beams, which are received and analyzed in terms of wavelength and/or time at two spaced apart light detectors. In a second embodiment, light from first and second sources is diffracted and compared in terms of wavelength and/or time to determine if the two beams arise from the same source. In a third embodiment, a light beam is split and diffracted and passed through first and second environments to study differential effects. In a fourth embodiment, diffracted light beam components, having first and second wavelengths, are received sequentially at a reaction site to determine whether a specified reaction is promoted, based on order of receipt of the beams. In a fifth embodiment, a cylindrically shaped diffraction grating (uniform or chirped) is rotated and translated to provide a sequence of diffracted beams with different wavelengths. In a sixth embodiment, incident light, representing one or more symbols, is successively diffracted from first and second diffraction gratings and is received at different light detectors, depending upon the wavelengths present in the incident light.

  12. Physical Activity in Early and Modern Populations. Papers from the Annual Meeting of the American Academy of Physical Education (59th, Las Vegas, Nevada, April 11-13, 1987). No. 21.

    ERIC Educational Resources Information Center

    Malina, Robert M., Ed.; Eckert, Helen M., Ed.

    Eleven conference papers explore physical activity in ancient societies as well as human adaptation of physical activities in modern society. The following papers are included: (1) "Physical Activity in Early and Modern Populations: An Evolutionary View" (Robert M. Malina); (2) "How Active Were Early Populations? or Squeezing the Fossil Record"…

  13. Friendship Network Characteristics Are Associated with Physical Activity and Sedentary Behavior in Early Adolescence

    PubMed Central

    Marks, Jennifer; de la Haye, Kayla; Barnett, Lisa M; Allender, Steven

    2015-01-01

    Introduction There is limited understanding of the association between peer social networks and physical activity (PA), sedentary and screen-related behaviors. This study reports on associations between personal network characteristics and these important health behaviors for early adolescents. Methods Participants were 310 students, aged 11–13 years, from fifteen randomly selected Victorian primary schools (43% response rate). PA and sedentary behaviors were collected via accelerometer and self-report questionnaire, and anthropometric measures via trained researchers. Participants nominated up to fifteen friends, and described the frequency of interaction and perceived activity intensity of these friends. Personal network predictors were examined using regression modelling for PA and sedentary/screen behavior. Results Perceived activity levels of friends, and friendships with very frequent interaction were associated with outside-of-school PA and/or sedentary/screen time. Differences according to sex were also observed in the association between network characteristics and PA and sedentary time. A higher number of friends and greater proportion of same sex friends were associated with boys engaging in more moderate-to-vigorous PA outside of school hours. PA intensity during school-day breaks was positively associated with having a greater proportion of friends who played sports for girls, and a greater proportion of male friends for boys. Conclusion Friendship network characteristics are associated with PA and sedentary/screen time in late childhood/early adolescence, and these associations differ by sex. The positive influence of very active peers may be a promising avenue to strengthen traditional interventions for the promotion of PA and reduction in screen time. PMID:26709924

  14. Documenting the conversion from traditional to Studio Physics formats at the Colorado School of Mines: Process and early results

    NASA Astrophysics Data System (ADS)

    Kohl, Patrick B.; Kuo, H. Vincent; Ruskell, Todd G.

    2008-10-01

    The Colorado School of Mines (CSM) has taught its first-semester introductory physics course using a hybrid lecture/Studio Physics format for several years. Over the past year we have converted the second semester of our calculus-based introductory physics course (Physics II) to a Studio Physics format, starting from a traditional lecture-based format. In this paper, we document the early stages of this conversion in order to better understand which features succeed and which do not, and in order to develop a model for switching to Studio that keeps the time and resource investment manageable. We describe the recent history of the Physics II course and of Studio at Mines, discuss the PER-based improvements that we are implementing, and characterize our progress via several metrics, including pre/post Conceptual Survey of Electricity and Magnetism (CSEM) scores, Colorado Learning About Science Survey scores (CLASS), solicited student comments, failure rates, and exam scores.

  15. Potentially Missing Physics of the Early Universe: Nonlinear Vacuum Polarization in Intense Blackbody Radiation

    SciTech Connect

    Wu, S Q; Hartemann, F V

    2010-04-13

    The standard Big Bang universe model is mainly based on linear interactions, except during exotic periods such as inflation. The purpose of the present proposal is to explore the effects, if any, of vacuum polarization in the very high energy density environment of the early universe. These conditions can be found today in astrophysical settings and may also be emulated in the laboratory using high intensity advanced lasers. Shortly after the Big Bang, there once existed a time when the energy density of the universe corresponded to a temperature in the range 10{sup 8} - 10{sup 9} K, sufficient to cause vacuum polarization effects. During this period, the nonlinear vacuum polarization may have had significant modifications on the propagation of radiation. Thus the thermal spectrum of the early universe may have been starkly non-Planckian. Measurements of the cosmic microwave background today show a spectrum relatively close to an ideal blackbody. Could the early universe have shown spectral deviations due to nonlinear vacuum effects? If so, is it possible to detect traces of those relic photons in the universe today? Found in galactic environments, compact objects such as blazars and magnetars can possess astronomically large energy densities that far exceed anything that can be created in the laboratory. Their field strengths are known to reach energy levels comparable to or surpassing the energy corresponding to the Schwinger critical field E {approx} 10{sup 18} V/m. Nonlinear vacuum effects become prominent under these conditions and have garnered much interest from the astronomical and theoretical physics communities. The effects of a nonlinear vacuum may be of crucial importance for our understanding of these objects. At energies of the order of the electron rest mass, the most important interactions are described by quantum electrodynamics (QED). It is predicted that nonlinear photon-photon interactions will occur at energies approaching the Schwinger

  16. Effect of physical effectiveness on digestibility of ration for cows in early lactation.

    PubMed

    Stojanovic, B; Grubic, G; Djordjevic, N; Bozickovic, A; Ivetic, A; Davidovic, V

    2014-08-01

    A study was conducted to investigate the effects of a diet particle size on nutrient digestibility in cows in early lactation. Treatments were diets with forage to concentrate ratio 43:57% in diet dry matter, with four different physically effective fibres (peNDF) content based on different cut length of corn silage and alfalfa haylage. The physical effectiveness factors (pef) and peNDF content of TMRs (total mixed ration) were determined using Penn State Particle Separator (PSPS) with two (pef8.0 , peNDF8.0) or three (pef1.18, peNDF1.18) sieves. The reducing of cut length of forages and particle size of diets did not affect on dry matter intake, while decreased peNDF intake by 16.34 and 8.83%, for peNDF8.0 and peNDF1.18 respectively. Apparent total tract digestibility of the nutrients was measured using two indicators: acid insoluble ash (AIA) and acid detergent insoluble lignin (ADL). Decreasing of forages cut length significantly increased apparent total tract digestibility of neutral detergent fibre (NDF) from 48.39% to 53.84% and from 53.9% to 58.66%, of crude protein from 73.96% to 79.24% and from 71.56% to 77.90%, with contemporary decreasing of non-fibre carbohydrate from 90.89% to 84.81% and from 91.99% to 86.80%, with AIA or ADL as indicator respectively. Dietary value of net energy for lactation (NEL) and energy intake was not affected by the peNDF content of the diet. PMID:24118628

  17. Very early-initiated physical rehabilitation protects against ischemic brain injury.

    PubMed

    Zhang, Pengyue; Zhang, Qi; Pu, Hongjian; Wu, Yi; Bai, Yulong; Vosler, Peter S; Chen, Jun; Shi, Hong; Gao, Yanqin; Hu, Yongshan

    2012-01-01

    Recent clinical data suggest that very early initiated physical rehabilitation (VEIPR) within 24 hours after stroke may reduce morbidity. However, there is limited evidence to support the beneficial effects of VEIPR and the underlying mechanisms are yet unknown. The present study investigated the effect of VEIPR on brain damage, inflammation, and neurobehavioral outcomes following cerebral ischemia. Rats that underwent transient focal cerebral ischemia (tFCI) were randomly assigned to VEIPR or non-exercise (NE) groups. VEIPR was induced 24 hours after the insult by initiating treadmill training for a maximum of 14 days while the NE group remained sedentary in their cages during this period. The results indicated that VEIPR significantly improved recovery of functional behavior as measured by neurological score, foot fault test, and Morris water maze performance. We also demonstrated that VEIPR significantly reduced infarct volume, brain water content, BBB damage, and acute inflammatory response. In summary, our results provide novel evidence that VEIPR confers marked neuroprotection against experimental stroke by attenuating pro-inflammatory reactions, brain edema, BBB damage, and cognitive and behavioral deficits. PMID:22652654

  18. First Light: Physics of Early Star Formation from the Local Universe

    NASA Astrophysics Data System (ADS)

    Pellegrini, Eric W.; Porter, R.; Stancil, P.

    2012-01-01

    We present detailed theoretical spectra of the earliest star forming regions. Improving on the spherically symmetric shell with a single ionization potential and density, we form a nebular template using the recently derived 3-D structure and density of 30 Doradus. Using CLOUDY, we illuminate our complex cloud with an SED of metal free stars, and vary the elemental and dust abundances from Z=-1 to -6. We solve for the physical condition of the gas as radiation is absorbed and reprocessed across the many different H+/H0/H2 interfaces forming the entire nebula. We solve for abundance and ionization states of all elements, as well as the abundance of 100's of molecular species which form after the ionizing radiation has been absorbed. We produce globally average, rest-frame synthetic spectra from 10-3 to 106µm allowing us to create empirically motivated diagnostics of early enrichment and stellar feedback for JWST and ALMA. This includes broad continuum features AND the atomic and molecular emission from the entire complex. With the structural and feedback details revealed in these models, there exists an unprecedented opportunity to illustrate the most promising observational strategies for new observatories peering back to first light. Future efforts to observe and create more templates using nearby HII regions will expand the modeled parameter space. These templates will also serve as an alternative to the current sub-grid structure of HII regions in cosmological simulations.

  19. Simultaneous study of mechanical property development and early hydration chemistry in Portland cement slurries using X-ray diffraction and ultrasound reflection

    SciTech Connect

    Jupe, Andrew C.; Wilkinson, Angus P.; Funkhouser, Gary P.

    2012-10-25

    A sample cell for the simultaneous measurement of synchrotron X-ray powder diffraction and ultrasound shear-wave reflection data from cement slurries is described. White cement slurries at 25 and 50 C with 0-3% bwoc CaCl{sub 2} were studied to illustrate the potential of the apparatus. The decrease in reflected S-wave amplitude, in dB, showed a linear correlation with C{sub 3}S hydration. CaCl{sub 2} retarded the development of G{prime} and G{double_prime} relative to the extent of C{sub 3}S hydration. At short times, there was a correlation between the time evolution of both G{prime} and G{double_prime}, and the amount of precipitated CH seen by diffraction, which was almost independent of CaCl{sub 2} concentration and temperature. CaCl{sub 2} addition resulted in a decrease in the amount of CH visible to X-rays, relative the degree of C{sub 3}S hydration. This may indicate a change in C-S-H gel C:S ratio or the presence of nanoscale CH that could not be seen by diffraction.

  20. Early Intervention Services for Children with Physical Disability: Parents' Perceptions of Family-Centeredness and Service Satisfaction

    ERIC Educational Resources Information Center

    Ziviani, Jenny; Feeney, Rachel B.; Khan, Asad

    2011-01-01

    Family-centered early childhood services for children with physical disability and their families can afford developmental advantage for children and avert unnecessary stress for families. This study aimed to determine how characteristics of children and families and perceptions of family-centered practice (FCP) relate to satisfaction with early…

  1. A Comparison of Student Knowledge between Traditional and Blended Instruction in a Physical Education in Early Childhood Course

    ERIC Educational Resources Information Center

    Giannousi, Maria; Vernadakis, Nikolaos; Derri, Vassiliki; Antoniou, Panagiotis; Kioumourtzoglou, Efthimis

    2014-01-01

    Blended learning model combines different advantages of face to face education and e-learning to ensure an effective learning environment for students. The purpose of this study was to investigate the impact of traditional and blended instruction, in students' knowledge in a Physical Education in Early Childhood course. For the purpose of…

  2. Body Size at Birth, Physical Development and Cognitive Outcomes in Early Childhood: Evidence from the Longitudinal Survey of Australian Children

    ERIC Educational Resources Information Center

    Ulker, Aydogan

    2016-01-01

    Using a rich sample created from the Longitudinal Survey of Australian Children, we investigate the extent to which the relationship between body size at birth and early childhood cognitive skills is mediated by physical development indicators. Consistent with existing evidence from other countries, we find a significant relationship between body…

  3. Parent and Peer Predictors of Physical Dating Violence Perpetration in Early Adolescence: Tests of Moderation and Gender Differences

    ERIC Educational Resources Information Center

    Miller, Shari; Gorman-Smith, Deborah; Sullivan, Terri; Orpinas, Pamela; Simon, Thomas R.

    2009-01-01

    This study examined parenting and peer predictors of physical dating violence perpetration during early adolescence and tested moderation among these predictors and gender. Participants were 2,824 ethnically diverse sixth-grade students with a recent boyfriend/girlfriend who was part of a multisite, longitudinal investigation of the development…

  4. Physical Environmental Adversity and the Protective Role of Maternal Monitoring in Relation to Early Child Conduct Problems

    ERIC Educational Resources Information Center

    Supplee, Lauren H.; Unikel, Emily B.; Shaw, Daniel S.

    2007-01-01

    Research on the development of externalizing behaviors during early childhood has focused on child and parenting factors. Fewer studies have investigated effects of aversive features of the micro-level physical environment, such as overcrowding and chaos in the home, and the macro-level environment, such as neighborhood quality. This study extends…

  5. Music and Physical Play: What Can We Learn from Early Childhood Teachers in Kenya?

    ERIC Educational Resources Information Center

    Freshwater, Amy; Sherwood, Elizabeth; Mbugua, Esther

    2008-01-01

    Sharing classroom practices across international borders can add new dimensions to teaching methods, no matter where one calls home. With this idea in mind, the authors (two U.S. early childhood teacher educators and a Kenyan-born U.S. early childhood teacher) have corresponded for several years through e-mail with a small group of early childhood…

  6. Simulation of blast-induced early-time intracranial wave physics leading to traumatic brain injury.

    PubMed

    Taylor, Paul A; Ford, Corey C

    2009-06-01

    The objective of this modeling and simulation study was to establish the role of stress wave interactions in the genesis of traumatic brain injury (TBI) from exposure to explosive blast. A high resolution (1 mm3 voxels) five material model of the human head was created by segmentation of color cryosections from the Visible Human Female data set. Tissue material properties were assigned from literature values. The model was inserted into the shock physics wave code, CTH, and subjected to a simulated blast wave of 1.3 MPa (13 bars) peak pressure from anterior, posterior, and lateral directions. Three-dimensional plots of maximum pressure, volumetric tension, and deviatoric (shear) stress demonstrated significant differences related to the incident blast geometry. In particular, the calculations revealed focal brain regions of elevated pressure and deviatoric stress within the first 2 ms of blast exposure. Calculated maximum levels of 15 KPa deviatoric, 3.3 MPa pressure, and 0.8 MPa volumetric tension were observed before the onset of significant head accelerations. Over a 2 ms time course, the head model moved only 1 mm in response to the blast loading. Doubling the blast strength changed the resulting intracranial stress magnitudes but not their distribution. We conclude that stress localization, due to early-time wave interactions, may contribute to the development of multifocal axonal injury underlying TBI. We propose that a contribution to traumatic brain injury from blast exposure, and most likely blunt impact, can occur on a time scale shorter than previous model predictions and before the onset of linear or rotational accelerations traditionally associated with the development of TBI. PMID:19449961

  7. Low Temperature Physics at Yale in the late 30's through the early 50's

    NASA Astrophysics Data System (ADS)

    Wheeler, Robert

    2006-03-01

    The low temperature program at Yale was initiated by C. T. Lane (1904-1991) in the fall of 1937 when he was appointed to the teaching staff as an instructor in the department of Physics. Following his doctorate from McGill in 1929 he investigated the magnetic susceptibilities of ``soft'' metals supported by the National Research Council of Canada, the Commissioners of the 1851 Exhibition and a Sterling Fellowship at Yale. Arranged by Louis McKeehan, with 5000 from the new George Sheffield research fund, he started the construction of a Kapitza type helium liquefier. The machine was largely completed in the fall of 1939, yet liquid helium was not made until early December 1940 due to the need for extensive on line purification of the gas. Returning in 1945 from war research, Lane and Henry A. Fairbank (Ph.D 1944) continued the metals work along with new thrusts into Second Sound , properties of helium^ three impurities in liquid helium and starting in the 50's on rotating He II. In 1933 both Lane and Onsager were awarded Sterling Fellowships, which initiated a stimulating experimental- theoretical exchange continuing until they both retired. The best-known example was the rediscovery at Yale of the deHaas-van Alphen effect, previously observed only in bismuth, in zinc; where upon Onsager and his students provided new insights into our understanding of the Fermi surface of metals. With the development of new instrumentation one observed vast changes in experimental style during this period. The evolution of the production of liquid helium from Lane's device though the Collins machine to the commodity business of today now makes experiments of huge size and importance possible.

  8. Diffraction techniques in engineering applications

    SciTech Connect

    Kozarczek, K.J.; Hubbard, C.R.; Watkins, T.R.; Wang, X.L.; Spooner, S.

    1995-12-31

    Diffraction techniques applied to crystalline materials provide quantitative information about the crystallographic structure and mechanical condition of the material. Those two characteristics influence the chemical, physical, and mechanical properties of a Component. A concerted application of x-ray and neutron diffraction allows one to comprehensively study the bulk and subsurface variations of such material characteristics as crystallographic texture, residual stress, and cold work. The Residual Stress User Center at the Oak Ridge National Laboratory offers academic and industrial researchers both neutron and x-ray diffraction capabilities. Recent examples of the application of work related to thin film, metal, ceramic and composite material technologies are presented.

  9. Implementing a Physical Activity Curriculum into the School Day: Helping Early Childhood Teachers Meet the Challenge

    ERIC Educational Resources Information Center

    Breslin, Casey Marie; Morton, Jane R.; Rudisill, Mary E.

    2008-01-01

    In Fall 2006, North Carolina kindergarten teachers were charged with the task of meeting the NASPE guidelines for providing daily physical activity to their kindergarten students. In turn, the teachers researched resources and consulted experts to design and develop a developmentally appropriate physical activity and physical play environment for…

  10. Comparing physical activity and sedentary time among overweight and nonoverweight preschoolers enrolled in early learning programs: a cross-sectional study.

    PubMed

    Tucker, Patricia; Maltby, Alana M; Burke, Shauna M; Vanderloo, Leigh M; Irwin, Jennifer D

    2016-09-01

    Establishing appropriate physical activity and sedentary behaviours during early childhood is important to ensure children accrue the many associated health benefits. While physical activity levels have been reported as low within early learning programs, little research has explored the physical activity and sedentary time of Canadian preschoolers classified as overweight within these facilities. The purpose of this study was to compare objectively measured physical activity and sedentary time among preschoolers classified as overweight and nonoverweight in early learning programs. Direct assessment of physical activity and sedentary time of 216 preschool-aged children was collected via Actical accelerometers during early learning hours, while body mass index percentile was calculated based on preschoolers' objectively measured height and weight. Results of three 3-way ANOVAs suggest that rates of moderate to vigorous physical activity, total physical activity, and sedentary time (p > 0.05) did not significantly differ based on weight status, sex, and type of early learning facility. This study is one of few that has examined differences in overweight and nonoverweight preschoolers' sedentary time, and adds to the limited research exploring physical activity levels among overweight and nonoverweight preschoolers during early learning hours. Given the high rates of sedentary time reported, programming within early learning facilities is necessary to support preschoolers, regardless of weight status, to achieve increased physical activity levels and decreased sedentary time. PMID:27532225

  11. Children’s delayed development and behavior problems: Impact on mothers’ perceived physical health across early childhood⋆

    PubMed Central

    Eisenhower, Abbey Severance; Baker, Bruce L.; Blacher, Jan

    2009-01-01

    Mothers of children with developmental delays may experience poorer psychological well-being than other mothers; however, little research has examined how delayed development in children might predict mothers’ perceived physical well-being. Children with delayed development manifest heightened behavior problems, which may negatively affect maternal well-being. We examined the associations between developmental delay and behavior problems at child age 3 and mothers’ self-perceived physical health at child ages 3, 4, and 5, in families of 218 children with and without developmental delays. The study sample comprised 218 families from central Pennsylvania and Southern California, USA who were recruited through community agencies that provide diagnostic and intervention services for individuals with development difficulties. We found that mothers of children with delayed development at age 3 reported poorer concurrent and later physical health than mothers of children with typical development. Broadening the analyses to include not only child development status (delayed development versus typical development) but also child behavior problems at age 3, only child behavior problems and the interaction of development status and behavior problems, but not development status itself, predicted maternal health. Early child behavior problems contributed to later maternal health above and beyond early maternal health, suggesting a possible causal association between child behavior problems and mothers’ physical health. The relation between child behavior problems and maternal health was moderated by mothers’ parenting stress and mediated by depressive symptoms. Mothers of children with both delayed development and high behavior problems are a particular risk group that may be especially in need of early intervention. Further research should examine the behavioral and biological pathways by which these child-related stressors influence mothers’ physical health. PMID

  12. New insight into the physics of atmospheres of early type stars

    NASA Technical Reports Server (NTRS)

    Lamers, H. J. G. L. M.

    1981-01-01

    The phenomenon of mass loss and stellar winds from hot stars are discussed. The mass loss rate of early type stars increases by about a factor of 100 to 1000 during their evolution. This seems incompatible with the radiation driven wind models and may require another explanation for the mass loss from early type stars. The winds of early type stars are strongly variable and the stars may go through active phases. Eclipses in binary systems by the stellar winds can be used to probe the winds. A few future IUE studies are suggested.

  13. Mathematics, Experiments, and Theoretical Physics: The Early Days of the Sommerfeld School

    NASA Astrophysics Data System (ADS)

    Eckert, Michael

    1999-10-01

    The names of his students read like a Who's Who of the pioneers in modern physics Peter Debye, Peter Paul Ewald, Wolfgang Pauli, Werner Heisenberg, Hans A. Bethe - to name only the most prominent. In retrospect, the success of Sommerfeld's school of modern theoretical physics tends to overshadow its less glorious beginnings. A century ago, theoretical physics was not yet considered as a distinct discipline. In this article I emphasize more the haphazard beginnings than the later achievements of Sommerfeld's school, which mirrored the state of theoretical physics before it became an independent discipline.

  14. A conceptual framework for organizational readiness to implement nutrition and physical activity programs in early childhood education settings.

    PubMed

    Sharma, Shreela V; Upadhyaya, Mudita; Schober, Daniel J; Byrd-Williams, Courtney

    2014-01-01

    Across multiple sectors, organizational readiness predicts the success of program implementation. However, the factors influencing readiness of early childhood education (ECE) organizations for implementation of new nutrition and physical activity programs is poorly understood. This study presents a new conceptual framework to measure organizational readiness to implement nutrition and physical activity programs in ECE centers serving children aged 0 to 5 years. The framework was validated for consensus on relevance and generalizability by conducting focus groups; the participants were managers (16 directors and 2 assistant directors) of ECE centers. The framework theorizes that it is necessary to have "collective readiness," which takes into account such factors as resources, organizational operations, work culture, and the collective attitudes, motivation, beliefs, and intentions of ECE staff. Results of the focus groups demonstrated consensus on the relevance of proposed constructs across ECE settings. Including readiness measures during program planning and evaluation could inform implementation of ECE programs targeting nutrition and physical activity behaviors. PMID:25357258

  15. Physical activity status of academic professors during their early career transition: an application of the theory of planned behavior.

    PubMed

    Kirk, Megan A; Rhodes, Ryan E

    2012-01-01

    Life-transitions (e.g. parenthood) have been linked to physical inactivity, yet the topic requires further exploration. In this study, we evaluated changes in the physical activity (PA) of adults during their early career transition using retrospective analysis and the theory of planned behavior. Recruitment from January to March 2010 yielded a random sample of 267 assistant professors, ages 25-44, employed within the last five years. Repeated measures analysis of variance (RM ANOVA) concluded that PA declined across the transition (d = 0.36-0.43) and was further attenuated by marriage, work hours, and parenthood status. Discriminant function analysis (DFA) identified specific behavioral and control correlates about PA enjoyment, limited time, inconsistent schedule, work demands, and job pressures to distinguish between those who remained active from those who did not across the transition. PA interventions administered prior to career transitions may be needed to prevent physical inactivity. PMID:22348598

  16. Perpetrators of Early Physical and Sexual Abuse among Homeless and Runaway Adolescents.

    ERIC Educational Resources Information Center

    Tyler, Kimberly A.; Cauce, Ana Mari

    2002-01-01

    Interviews with 372 homeless and runaway adolescents found one-half reported being physically abused and almost one-third experienced sexual abuse. Females experienced significantly higher rates of sexual abuse. Sexual minority youth experienced more physical and sexual abuse compared to heterosexual youth. Nonfamily members most often perpetrated…

  17. Physical Education, Youth Sport and Lifelong Participation: The Importance of Early Learning Experiences

    ERIC Educational Resources Information Center

    Kirk, David

    2005-01-01

    The PESSCLS strategy for physical education and youth sport in England has received an unprecedented level of funding from the Blair government during its term in office. In this article, it is proposed that there are structural problems with the delivery of physical education and school sport in England that the PESSCLS strategy and associated…

  18. Does Built Environment Matter to Early Adolescents' Physical Activity?

    ERIC Educational Resources Information Center

    Lin, Jen-Jia; Ting, Tzu-Cheng

    2014-01-01

    This study examined the relationship of built environments to physical activity among adolescents aged 12 to 14 years old. The study sample included 269 junior high school students studying in Nangang District, Taipei, Taiwan. Sample physical activity data were obtained by surveying adolescents using a self-administered short version of the…

  19. Grounding Early Intervention: Physical Therapy Cannot Just Be About Motor Skills Anymore

    PubMed Central

    Harbourne, Regina T.; Dusing, Stacey C.; McCoy, Sarah Westcott

    2013-01-01

    This perspective article provides support for 4 interrelated tenets: grounded perceptual-motor experience within cultural and social contexts forms cognition; exploration through early behaviors, such as object interaction, sitting, and locomotion, broadly facilitates development; infants and children with limited exploration are at risk for global developmental impairments; and early interventions targeting exploratory behaviors may be feasible and effective at advancing a range of abilities across developmental domains and time. These tenets emphasize that through the promotion of early perceptual-motor behaviors, broader, more global developmental advancements can be facilitated and future delays can be minimized across domains for infants and children with special needs. Researchers, educators, and clinicians should build on these tenets to further demonstrate the effectiveness of targeted early interventions. The goals of these interventions should be not only to advance targeted perceptual-motor skills in the moment but also to more broadly advance future abilities and meet the early intervention goal of maximizing children's learning potential. PMID:23001524

  20. Physical Therapy and Infants with Down's Syndrome: The Effects of Early Intervention.

    ERIC Educational Resources Information Center

    Harris, Susan R.

    1981-01-01

    The neuromotor development of Down's syndrome (DS) infants is reviewed, current physical therapy approaches are cited, a neurodevelopmental treatment (NDT) approach is described, and a study on the effects of NDT on motor performance in DS infants is reported. (SB)

  1. An assemblage of science and home. The gendered lifestyle of Svante Arrhenius and early twentieth-century physical chemistry.

    PubMed

    Bergwik, Staffan

    2014-06-01

    This essay explores the gendered lifestyle of early twentieth-century physics and chemistry and shows how that way of life was produced through linking science and home. In 1905, the Swedish physical chemist Svante Arrhenius married Maja Johansson and established a scientific household at the Nobel Institute for Physical Chemistry in Stockholm. He created a productive context for research in which ideas about marriage and family were pivotal. He also socialized in similar scientific sites abroad. This essay displays how scholars in the international community circulated the gendered lifestyle through frequent travel and by reproducing gendered behavior. Everywhere, husbands and wives were expected to perform distinct duties. Shared performances created loyalties across national divides. The essay thus situates the physical sciences at the turn of the twentieth century in a bourgeois gender ideology. Moreover, it argues that the gendered lifestyle was not external to knowledge making but, rather, foundational to laboratory life. A legitimate and culturally intelligible lifestyle produced the trust and support needed for collaboration. In addition, it enabled access to prestigious facilities for Svante Arrhenius, ultimately securing his position in international physical chemistry. PMID:25154133

  2. Psychosocial Correlates of Physical Dating Violence Victimization among Latino Early Adolescents

    ERIC Educational Resources Information Center

    Yan, Fang A.; Howard, Donna E.; Beck, Kenneth H.; Shattuck, Teresa; Hallmark-Kerr, Melissa

    2010-01-01

    This study examined the association between dating violence victimization and psychosocial risk and protective factors among Latino early adolescents. An anonymous, cross-sectional, self-reported survey was administered to a convenience sample of Latino youth (n = 322) aged 11 to 13 residing in suburban Washington, D.C. The dependent variable was…

  3. Early Adolescent Sexual Initiation and Physical/Psychological Symptoms: A Comparative Analysis of Five Nations

    ERIC Educational Resources Information Center

    Madkour, Aubrey Spriggs; Farhat, Tilda; Halpern, Carolyn Tucker; Godeau, Emmanuelle; Nic Gabhainn, Saoirse

    2010-01-01

    Although most people in developed countries experience sexual initiation during adolescence, little is known about inter-country variability in the psychosocial correlates of early initiation. Population-based samples of 15-year-olds (n = 6,111, 52% female) who participated in the Health Behaviors in School-Aged Children Study (Finland, Scotland,…

  4. "Intensive Mothering" in the Early Years: The Cultivation and Consolidation of (Physical) Capital

    ERIC Educational Resources Information Center

    Stirrup, Julie; Duncombe, Rebecca; Sandford, Rachel

    2015-01-01

    Growing pressure on parents to equip their children with the skills required for future success, coupled with an increased focus on providing quality learning experiences in the early years, has contributed to an upsurge in the enrolment of young children in formal (often privatised) activities. Moreover, in response to growing societal concerns…

  5. Physical Activity, Self-Regulation, and Early Academic Achievement in Preschool Children

    ERIC Educational Resources Information Center

    Becker, Derek R.; McClelland, Megan M.; Loprinzi, Paul; Trost, Stewart G.

    2014-01-01

    Research Findings: The present study investigated whether active play during recess was associated with self-regulation and academic achievement in a prekindergarten sample. A total of 51 children in classes containing approximately half Head Start children were assessed on self-regulation, active play, and early academic achievement. Path…

  6. A Strategy for Embedding Functional Motor and Early Numeracy Skill Instruction into Physical Education Activities

    ERIC Educational Resources Information Center

    Whinnery, Stacie B.; Whinnery, Keith W.; Eddins, Daisy

    2016-01-01

    This article addresses the challenges educators face when attempting to find a balance between both functional and academic skill instruction for students with severe, multiple disabilities including motor impairments. The authors describe a strategy that employs embedded instruction of early numeracy and functional motor skills during physical…

  7. Physical Growth and Maturation Following Early Severe Institutional Deprivation: Do They Mediate Specific Psychopathological Effects?

    ERIC Educational Resources Information Center

    Sonuga-Barke, Edmund J.; Schlotz, Wolff; Rutter, Michael

    2010-01-01

    The authors' previous work and the data reported in the preceding chapters of this monograph provide conclusive evidence of the persistent nature of the negative impact of early severe deprivation. Institutional deprivation, despite the good outcomes for many, was often associated with substantial impairment and disorder across a wide range of…

  8. PROPOSED WATER QUALITY SURVEILLANCE NETWORK USING PHYSICAL, CHEMICAL AND BIOLOGICAL EARLY WARNING SYSTEMS (CBEWS)

    EPA Science Inventory

    The Homeland Protection Act of 2002 specifically calls for the investigation and use of Early Warning Systems (EWS) for water security reasons. The EWS is a screening tool for detecting changes in source water and distribution system water quality. A suite of time-relevant biol...

  9. PROPOSED WATER QUALITY SURVEILLANCE NETWORK USING PHYSICAL, CHEMICAL AND BIOLOGICAL EARLY WARNING SYSTEMS (BEWS)

    EPA Science Inventory

    The Homeland Protection Act of 2002 specifically calls for the investigation and use of Early Warning Systems (EWS) for water security reasons. The EWS is a screening tool for detecting changes in source water and distribution system water quality. A suite of time-relevant biol...

  10. Early postnatal nutrition determines adult physical activity and energy expenditure in female mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Decades of research in rodent models has shown that early postnatal overnutrition induces excess adiposity and other components of metabolic syndrome that persist into adulthood. The specific biologic mechanisms explaining the persistence of these effects, however, remain unknown. On postnatal day 1...

  11. Electronically- and crystal-structure-driven magnetic structures and physical properties of RScSb (R = rare earth) compounds. A neutron diffraction, magnetization and heat capacity study

    SciTech Connect

    Ritter, C; Dhar, S K; Kulkarni, R; Provino, A; Paudyal, Durga; Manfrinetti, Pietro; Gschneidner, Karl A

    2014-08-14

    The synthesis of the new equiatomic RScSb ( R = La-Nd, Sm, Gd-Tm, Lu, Y) compounds has been recently reported. These rare earth compounds crystallize in two different crystal structures, adopting the CeScSi-type ( I 4/ mmm) for the lighter R (La-Nd, Sm) and the CeFeSi-type (P4 /nmm) structure for the heavier R ( R = Gd-Tm, Lu, Y). Here we report the results of neutron diffraction, magnetization and heat capacity measurements on some of these compounds ( R = Ce, Pr, Nd, Gd and Tb). Band structure calculations have also been performed on CeScSb and GdScGe (CeScSi-type), and on GdScSb and TbScSb (CeFeSi-type) to compare and understand the exchange interactions in CeScSi and CeFeSi structure types. The neutron diffraction investigation shows that all five compounds order magnetically, with the highest transition temperature of 66 K in TbScSb and the lowest of about 9 K in CeScSb. The magnetic ground state is simple ferromagnetic (τ = [0 0 0]) in CeScSb, as well in NdScSb for 32 >T > 22 K. Below 22 K a second magnetic transition, with propagation vector τ = [¼ ¼ 0], appears in NdScSb. PrScSb has a magnetic structure within, determined by mostly ferromagnetic interactions and antiferromagnetic alignment of the Pr-sites connected through the I-centering ( τ = [1 0 0]). A cycloidal spiral structure with a temperature dependent propagation vector τ = [δ δ ½] is found in TbScSb. The results of magnetization and heat capacity lend support to the main conclusions derived from neutron diffraction. As inferred from a sharp peak in magnetization, GdScSb orders antiferromagnetically at 56 K. First principles calculations show lateral shift of spin split bands towards lower energy from the Fermi level as the CeScSi-type structure changes to the CeFeSi-type structure. This rigid shift may force the system to transform from exchange split ferromagnetic state to the antiferromagnetic state in RScSb compounds (as seen for example in GdScSb and TbScSb) and is proposed to

  12. Physical and Sexual Abuse and Early-Onset Bipolar Disorder in Youths Receiving Outpatient Services: Frequent, but Not Specific

    PubMed Central

    Youngstrom, Eric A.; Martinez, Maria; KogosYoungstrom, Jennifer; Scovil, Kelly; Ross, Jody; Feeny, Norah C.; Findling, Robert L.

    2014-01-01

    The objective of this study was to determine if physical and sexual abuse showed relationships to early-onset bipolar spectrum disorders (BPSD) consistent with findings from adult retrospective data. Participants (N=829, M= 10.9 years old ±3.4 SD, 60 % male, 69 % African American, and 18 % with BPSD), primarily from a low socio-economic status, presented to an urban community mental health center and a university research center. Physical abuse was reported in 21 %, sexual abuse in 20 %, and both physical and sexual abuse in 11 % of youths with BPSD. For youths without BPSD, physical abuse was reported in 16 %, sexual abuse in 15 %, and both physical and sexual abuse in 5 % of youths. Among youth with BPSD, physical abuse was significantly associated with a worse global family environment, more severe depressive and manic symptoms, a greater number of sub-threshold manic/hypomanic symptoms, a greater likelihood of suicidality, a greater likelihood of being diagnosed with PTSD, and more self-reports of alcohol or drug use. Among youth with BPSD, sexual abuse was significantly associated with a worse global family environment, more severe manic symptoms, a greater number of sub-threshold manic/hypomanic symptoms, greater mood swings, more frequent episodes, more reports of past hospitalizations, and a greater number of current and past comorbid Axis I diagnoses. These findings suggest that if physical and/or sexual abuse is reported, clinicians should note that abuse appears to be related to increased severity of symptoms, substance use, greater co-morbidity, suicidality, and a worse family environment. PMID:25118660

  13. Substance misuse and the physical environment: the early action on a newly completed field.

    PubMed

    Gifford, R; Hine, D W

    Transactions between individuals and their physical settings involving consciousness-altering drugs are examined. Research has gradually expanded outward from the individual and the drug to include the social and, finally, the physical context of drug use and misuse. Similarly, theory has evolved from simple unidirectional causal tenets to complex multidirectional contextual tenets. Research to date is sparse and does not live up to the ambitious vision of current theoretical views, but some results are striking and provocative. The review is framed in terms of physical scale (macro-, meso-, and microenvironments) and specificity (from molecular features of a setting to molar environmental characteristics such as stimulation level). Three temporal phases are considered: the development, maintenance, and cessation of substance misuse. The paucity of empirical research combined with the potential importance of environmental factors means that many challenging questions remain for a new generation of researchers. PMID:2131322

  14. Early inner solar system impactors: physical properties of comet nuclei and dust particles revisited.

    PubMed

    Levasseur-Regourd, A C; Lasue, J; Desvoivres, E

    2006-12-01

    During the epoch of early bombardment, terrestrial planets have been heavily impacted by cometary nuclei and cometary dust particles progressively injected in the interplanetary medium. Stardust and Deep Impact missions confirm that the nuclei are porous, loosely consolidated objects, with densities below 1,000 kg m(-3), and that they often release small fragments of ices and dust. Recent numerical simulations of the light scattering properties of cometary dust particles indicate that they are highly porous, most likely fractal, and rich in absorbing organics compounds (with a mixture ratio of e.g. 33 to 60% in mass for comet Hale-Bopp). Taking into account the fact that porous structures survive more easily than compact ones during atmospheric entry, such results reinforce the scenario of the early terrestrial planets enrichment--in organics needed for life to originate--by comets. PMID:17120128

  15. Role of Physical Evaluation in the Early Identification of Axial Spondyloarthritis: A Research Proposal

    PubMed Central

    Castro, Marcelo P; Stebbings, Simon M; Milosavljevic, Stephan; Bussey, Melanie D

    2015-01-01

    The aim of this study was to present a rationale to explore the use of clinical tests for the sacroiliac joints to detect early axial spondyloarthritis (SpA) and to suggest a protocol to validate these clinical tests. Based on the European Guidelines for Diagnosis and Treatments of Pelvic Girdle Pain, we propose a set of six clinical tests to identify the likely presence of inflammation in the sacroiliac joints associated with early axial SpA. As magnetic resonance imaging (MRI) is the current gold standard used to identify inflammation in the sacroiliac joints, the results of the proposed set of clinical tests are compared with those from the MRI examinations. We hypothesize that specific clinical tests, which combine pain provocation and functional tests, for assessing the sacroiliac joints will help to identify early active inflammation at the sacroiliac joints in axial SpA. If such tests prove to be sensitive and specific, they could add further value to the diagnostic classification criteria for axial SpA. PMID:26448694

  16. Psychosocial Influences on Physical, Verbal, and Indirect Bullying Among Japanese Early Adolescents

    ERIC Educational Resources Information Center

    Ando, Mikayo; Asakura, Takashi; Simons-Morton, Bruce

    2005-01-01

    Although bullying among Japanese youth is a current major concern, psychosocial influences on bullying are not fully understood. The purpose of this study was to identify the psychosocial factors associated with physical, verbal, and indirect bullying among Japanese adolescents. Junior high school students between seventh and ninth grade (N =…

  17. Early Childhood Teachers' and Staff Members' Perceptions of Nutrition and Physical Activity Practices for Preschoolers

    ERIC Educational Resources Information Center

    Derscheid, Linda E.; Umoren, Josephine; Kim, So-Yeun; Henry, Beverly W.; Zittel, Lauriece L.

    2010-01-01

    Child care teachers and staff are important influences on preschoolers' nutrition and physical activity habits, and their views may be influenced by education level, years of field experience, and program involvement. For the 360 participants surveyed, responses on 5 of 18 survey items significantly differed by education level (e.g., less…

  18. Stepping toward Physical Activity Requirements: Integrating Pedometers into Early Childhood Settings

    ERIC Educational Resources Information Center

    Robinson, Leah E.; Wadsworth, Danielle D.

    2010-01-01

    Physical activity is an essential component for lifelong wellness and the quality of life. Over the past years, childhood obesity has dramatically increased. Data supports that young children are adopting sedentary behaviors within and outside of school hours that may contribute to obesity and other health-related diseases. This paper provides…

  19. Physical Activity Promotes Academic Achievement and a Healthy Lifestyle when Incorporated into Early Childhood Education

    ERIC Educational Resources Information Center

    Abadie, Ben R.; Brown, Stanley P.

    2010-01-01

    The detrimental effects of physical inactivity within children have enormous personal health consequences. These health conditions have the potential to impact the economic vitality of society as a whole. Studies have indicated that inactive children are far more likely to suffer from obesity, type II diabetes, and hypertension than their…

  20. The Role of Physical Contact and Association in Early Contamination Sensitivity.

    ERIC Educational Resources Information Center

    Springer, Ken; Belk, Amy

    1994-01-01

    Children were asked whether someone would get sick from drinking juice placed near a bug. Some preschoolers and most seven- and eight-year olds recognized the need for physical contact with the bug to make the juice noxious, whereas some believed the mere presence of a contaminant made it noxious. Thus, associational contamination sometimes plays…

  1. Physical Punishment and Education in Early Childhood: The Case of Finland.

    ERIC Educational Resources Information Center

    Husa, Sari

    In Finland, physical punishment of children is clearly forbidden by the Child Custody Act of 1983, but studies show that up to 72 percent of children under age 14 have experienced corporal punishment at home. This conflict is the subject of the proposed research study described in this article. The article begins with a legislative history of…

  2. Parent and Peer Predictors of Physical Dating Violence Perpetration in Early Adolescence: Tests of Moderation and Gender Differences

    PubMed Central

    Miller, Shari; Gorman-Smith, Deborah; Sullivan, Terri; Orpinas, Pamela; Simon, Thomas R.

    2013-01-01

    This study examined parenting and peer predictors of physical dating violence perpetration during early adolescence and tested moderation among these predictors and gender. Participants were 2,824 ethnically diverse sixth-grade students with a recent boyfriend/girlfriend who was part of a multisite, longitudinal investigation of the development and prevention of violence among middle school students. Those students who reported having a boyfriend/girlfriend reported significantly more drug use and delinquent activity and were more likely to be male. Twenty-nine percent of youth with a boyfriend/girlfriend reported perpetrating physical aggression against their boyfriend/girlfriend. Parenting and peer variables were significant predictors of physical dating violence. However, gender moderated the association between parenting practices and physical dating violence, with parental monitoring inversely linked to dating violence for boys and parent support for nonaggression inversely linked to dating violence for girls. Parent support for aggression also moderated the association between peer deviancy and reported perpetration. Finally, gender moderated the interaction between peer deviancy and parent support for nonaggressive solutions. PMID:20183640

  3. Physical activity in young children and their parents–An Early STOPP Sweden–China comparison study

    PubMed Central

    Johansson, Elin; Mei, Hong; Xiu, Lijuan; Svensson, Viktoria; Xiong, Yueling; Marcus, Claude; Zhang, Jianduan; Hagströmer, Maria

    2016-01-01

    Understanding about socio-cultural differences in physical activity in children with high and low risk for obesity can help tailor intervention programs in different settings. This study aimed to compare objectively measured physical activity in two-year-olds and their parents, living in Stockholm, Sweden, and Wuhan, China. Data from Early STOPP was used. Children and parents wore an accelerometer in connection with the child’s second birthday. Weekly and hourly patterns were examined. Correlation between child and parental physical activity was assessed. Data on 146 Swedish and 79 Chinese children and their parents was available. Children, mothers and fathers in Stockholm were significantly more active than their counterparts in Wuhan (children; 2989 (SD 702) vs. 1997 (SD 899) counts per minute (CPM), mothers 2625 (SD 752) vs. 2042 (SD 821) CPM; fathers 2233 (SD 749) vs. 1588 (SD 754) CPM). Activity levels were similar over a week for children and parents within both countries. No parental-child correlations, except for a paternal-son correlation in Stockholm, were found. Children, mothers and fathers in Stockholm are more active compared with their counterparts in Wuhan. Interventions to increase physical activity needs to take cultural aspects into account, also when targeting very young children. PMID:27404563

  4. Physical activity in young children and their parents-An Early STOPP Sweden-China comparison study.

    PubMed

    Johansson, Elin; Mei, Hong; Xiu, Lijuan; Svensson, Viktoria; Xiong, Yueling; Marcus, Claude; Zhang, Jianduan; Hagströmer, Maria

    2016-01-01

    Understanding about socio-cultural differences in physical activity in children with high and low risk for obesity can help tailor intervention programs in different settings. This study aimed to compare objectively measured physical activity in two-year-olds and their parents, living in Stockholm, Sweden, and Wuhan, China. Data from Early STOPP was used. Children and parents wore an accelerometer in connection with the child's second birthday. Weekly and hourly patterns were examined. Correlation between child and parental physical activity was assessed. Data on 146 Swedish and 79 Chinese children and their parents was available. Children, mothers and fathers in Stockholm were significantly more active than their counterparts in Wuhan (children; 2989 (SD 702) vs. 1997 (SD 899) counts per minute (CPM), mothers 2625 (SD 752) vs. 2042 (SD 821) CPM; fathers 2233 (SD 749) vs. 1588 (SD 754) CPM). Activity levels were similar over a week for children and parents within both countries. No parental-child correlations, except for a paternal-son correlation in Stockholm, were found. Children, mothers and fathers in Stockholm are more active compared with their counterparts in Wuhan. Interventions to increase physical activity needs to take cultural aspects into account, also when targeting very young children. PMID:27404563

  5. Safeguards-by-Design: Early Integration of Physical Protection and Safeguardability into Design of Nuclear Facilities

    SciTech Connect

    T. Bjornard; R. Bean; S. DeMuth; P. Durst; M. Ehinger; M. Golay; D. Hebditch; J. Hockert; J. Morgan

    2009-09-01

    The application of a Safeguards-by-Design (SBD) process for new nuclear facilities has the potential to minimize proliferation and security risks as the use of nuclear energy expands worldwide. This paper defines a generic SBD process and its incorporation from early design phases into existing design / construction processes and develops a framework that can guide its institutionalization. SBD could be a basis for a new international norm and standard process for nuclear facility design. This work is part of the U.S. DOE’s Next Generation Safeguards Initiative (NGSI), and is jointly sponsored by the Offices of Non-proliferation and Nuclear Energy.

  6. Inquiry with Laser Printer Diffraction Gratings

    ERIC Educational Resources Information Center

    Van Hook, Stephen J.

    2007-01-01

    The pages of "The Physics Teacher" have featured several clever designs for homemade diffraction gratings using a variety of materials--cloth, lithographic film, wire, compact discs, parts of aerosol spray cans, and pseudoliquids and pseudosolids. A different and inexpensive method I use to make low-resolution diffraction gratings takes advantage…

  7. Early-life physical activity reverses metabolic and Foxo1 epigenetic misregulation induced by gestational sleep disturbance

    PubMed Central

    Mutskov, Vesco; Khalyfa, Abdelnaby; Wang, Yang; Carreras, Alba; Nobrega, Marcelo A.

    2015-01-01

    Sleep disorders are highly prevalent during late pregnancy and can impose adverse effects, such as preeclampsia and diabetes. However, the consequences of sleep fragmentation (SF) on offspring metabolism and epigenomic signatures are unclear. We report that physical activity during early life, but not later, reversed the increased body weight, altered glucose and lipid homeostasis, and increased visceral adipose tissue in offspring of mice subjected to gestational SF (SFo). The reversibility of this phenotype may reflect epigenetic mechanisms induced by SF during gestation. Accordingly, we found that the metabolic master switch Foxo1 was epigenetically misregulated in SFo livers in a temporally regulated fashion. Temporal Foxo1 analysis and its gluconeogenetic targets revealed that the epigenetic abnormalities of Foxo1 precede the metabolic syndrome phenotype. Importantly, regular physical activity early, but not later in life, reversed Foxo1 epigenetic misregulation and altered the metabolic phenotype in gestationally SF-exposed offspring. Thus, we have identified a restricted postnatal period during which lifestyle interventions may reverse the Foxo1 epigenetically mediated risk for metabolic dysfunction later in the life, as induced by gestational sleep disorders. PMID:25568076

  8. Early and late physical and psychosocial effects of primary surgery in patients with oral and oropharyngeal cancers: a systematic review.

    PubMed

    Mortensen, Annelise; Jarden, Mary

    2016-06-01

    The purpose of this systematic review is to explore early and late physical and psychosocial effects of primary surgery for oral and oropharyngeal cancers and to investigate the factors that influence these effects. PubMed, Cinahl, and PsycInfo were searched for studies concerning patients diagnosed with oral and oropharyngeal cancers and treated with primary surgery and which followed the treatment trajectory from time of diagnosis to 10 years after surgery; these studies reported the quantitative assessments and qualitative experiences of the patient's physical and psychosocial well-being. Of the 438 articles accessed, 20 qualified for inclusion, of which 16 and 4 were quantitative and qualitative articles, respectively, and mainly quality-of-life assessments. Time of measurement ranged from time of diagnosis to 9 years after the surgical procedure. The total number of patients included in this review was 3386; of these, 1996 were treated by surgery alone and 1390 with combined surgery and adjuvant radiation therapy and/or chemotherapy. The studies showed that because of the nature of their disease, patients are negatively affected by the different types of surgical treatment for oral and oropharyngeal cancers, with both early and late interrelated effects, and by the side effects of adjuvant therapy. PMID:26948021

  9. Early social and physical deprivation leads to reduced social motivation in adulthood in Wistar rats.

    PubMed

    Mintz, Matti; Rüedi-Bettschen, Daniela; Feldon, Joram; Pryce, Christopher R

    2005-01-30

    Behavioural abnormalities in adulthood may have their origin in a disturbed interaction with the environment during postnatal development. We tested the consequences for adult social motivation of early deprivation (ED) of rat pups from mothers and littermates relative to nonhandled (NH) pups. Early deprivation was performed at room or warm ambient temperatures, cold-ED and warm-ED, respectively, and during either the dark or light phase of the daily cycle. In adulthood, rats that were unrelated and unfamiliar but of the same treatment group were introduced in pairs to an open field for a 30-min test. Social behaviour in home base and exploration modes was assessed using algorithmic analysis of the XY locations of the two rats. Findings revealed that Cold-ED induced a preference for a separate home base, which limited significantly the episodes of social interactions, in comparison to NH. Warm-ED had no comparable effect on the rats' social behaviour. These findings indicate that ED under ambient conditions that constitute severe thermal stress for rat pups leads to development of reduced social motivation in adulthood. PMID:15582117

  10. Childhood Disadvantage and Health Problems in Middle and Later Life: Early Imprints on Physical Health?

    PubMed Central

    Ferraro, Kenneth F.; Schafer, Markus H.; Wilkinson, Lindsay R.

    2016-01-01

    Drawing from cumulative inequality theory, we examine the relationship between childhood disadvantage and health problems in adulthood. Using two waves of data from Midlife Development in the United States, we investigate whether childhood disadvantage is associated with adult disadvantage, including fewer social resources, and the effect of lifelong disadvantage on health problems measured at the baseline survey and a 10-year follow-up. Findings reveal that childhood socioeconomic disadvantage and frequent abuse by parents are generally associated with fewer adult social resources and more lifestyle risks. Health problems, in turn, are affected by childhood disadvantage and by lifestyle risks, especially smoking and obesity. Not only was early disadvantage related to health problems at the baseline survey, but childhood socioeconomic disadvantage and frequent abuse also were related to the development of new health problems at the follow-up survey. These findings reveal the imprint of early disadvantage on health decades later and suggest greater attention to resources, even during midlife, can interrupt the chain of risks. PMID:27445413

  11. CONSTRAINING GAMMA-RAY BURST EMISSION PHYSICS WITH EXTENSIVE EARLY-TIME, MULTIBAND FOLLOW-UP

    SciTech Connect

    Cucchiara, A.; Cenko, S. B.; Bloom, J. S.; Morgan, A.; Perley, D. A.; Li, W.; Butler, N. R.; Filippenko, A. V.; Melandri, A.; Kobayashi, S.; Smith, R. J.; Mundell, C. G.; Steele, I. A.; Hora, J. L.; Da Silva, R. L.; Prochaska, J. X.; Worseck, G.; Fumagalli, M.; Cobb, B.; and others

    2011-12-20

    Understanding the origin and diversity of emission processes responsible for gamma-ray bursts (GRBs) remains a pressing challenge. While prompt and contemporaneous panchromatic observations have the potential to test predictions of the internal-external shock model, extensive multiband imaging has been conducted for only a few GRBs. We present rich, early-time, multiband data sets for two Swift events, GRB 110205A and GRB 110213A. The former shows optical emission since the early stages of the prompt phase, followed by the steep rising in flux up to {approx}1000 s after the burst (t{sup -{alpha}} with {alpha} = -6.13 {+-} 0.75). We discuss this feature in the context of the reverse-shock scenario and interpret the following single power-law decay as being forward-shock dominated. Polarization measurements, obtained with the RINGO2 instrument mounted on the Liverpool Telescope, also provide hints on the nature of the emitting ejecta. The latter event, instead, displays a very peculiar optical to near-infrared light curve, with two achromatic peaks. In this case, while the first peak is probably due to the onset of the afterglow, we interpret the second peak to be produced by newly injected material, signifying a late-time activity of the central engine.

  12. Early diagnosis of Lemierre's syndrome based on a medical history and physical findings.

    PubMed

    Murata, Yutaka; Wada, Mikio; Kawashima, Atsushi; Kagawa, Keizo

    2013-01-01

    A 37-year-old woman presented with fever and rigor after experiencing respiratory symptoms the previous week that had resolved within a few days. On presentation, her neck was swollen along the right sternocleidomastoid muscle, and chest CT showed pulmonary septic embolisms. Lemierre's syndrome was strongly suspected based on the patient's medical history and physical findings. Further examination revealed venous thrombus, and Fusobacterium necrophorum was later isolated from blood cultures. Antibiotics for anaerobes were administered before a final diagnosis was made, and the patient's symptoms thereafter improved. A rapid diagnosis is essential, since Lemierre's syndrome can be fatal with a diagnostic delay. PMID:23318865

  13. Physical changes of significance for early post mortem water distribution in porcine M. longissimus.

    PubMed

    Bertram, Hanne Christine; Schäfer, Annette; Rosenvold, Katja; Andersen, Henrik Jørgen

    2004-04-01

    The post mortem changes in water mobility and distribution were followed in porcine muscle (M. longissimus dorsi) samples using continuous low-field NMR relaxation measurements and simultaneous measurement of changes in muscle impedance as an indirect measure of membrane integrity as well as muscle contraction measurements using a rigormeter instrument. Distributed exponential fitting analysis of NMR T(2) relaxation data revealed the presence of three distinct water populations (T(20), T(21), T(22)) within the muscle during its conversion to meat. Comparison of T(2) relaxation patterns and contraction data indicates that rigor development affects the attributes of the T(21) water population and thereby contributes to myofibrillar water characteristics post mortem, as the T(21) water population is believed to reflect inter/intra-myofibrillar water. The volume of the water population believed to reflect extra-cellular water (T(22)) in the living muscle. Early post mortem T(22) decreased slightly within the first 2-3 h post mortem followed by an increase and a change in its characteristic time constant. This was ascribed to an initial muscle cell swelling followed by water being expelled from the cellular space into the extra-myofibrillar space. Comparison of changes in the T(22) water population and impedance characteristics within the muscle during its conversion to meat revealed close relationship between progresses in the two attributes. Obtained data strongly support that the post mortem reorganization of water is closely associated with membrane properties, which moreover was found to affect the final water-holding capacity of the meat. Finally, a model for early post mortem events leading to changes in the distribution of water within muscles is proposed. PMID:22061025

  14. Osteoporosis in otherwise healthy perimenopausal and early postmenopausal women: physical and biochemical characteristics.

    PubMed

    Pouillès, Jean-Michel; Trémollieres, Florence A; Ribot, Claude

    2006-02-01

    Population studies have shown that about 3-5% of perimenopausal women already have osteoporosis according to the WHO definition of osteoporosis for postmenopausal women ( t -scoreearly postmenopausal women (mean age 52.2+/-2.5 years) who were found to have apparently unexplained low bone mass, and we compared them to 120 controls matched for age and menopausal status. These women were extensively investigated, including by detailed questionnaire and laboratory testing. Of the 60 women with osteoporosis, only three were found to have previously undiagnosed disorders (two with subclinical hyperthyroidism and one with elevated serum PTH levels) that might have contributed to their low bone mass. On the other hand, osteoporotic patients were characterized by a significantly lower body weight, higher prevalence of personal and parental histories of fractures and a higher level of bone turnover as assessed by increased serum osteocalcin and bone alkaline phosphatase levels and urinary type I collagen C-telopeptide (CTX) excretion, as compared to controls. These findings support theories of a genetic contribution to osteoporosis and underline the predictive value of a previous history of personal and familial fracture in the identification of osteoporosis in early postmenopausal women. PMID:16021526

  15. Individual and social network predictors of physical bullying: a longitudinal study of Taiwanese early adolescents.

    PubMed

    Wei, Hsi-Sheng; Lee, Wonjae

    2014-01-01

    This study followed 125 7th-grade students in Taiwan for the entire school year and analyzed the individual and social network factors predicting their involvement in physical bullying over 5 waves of data. Using self-reports of bullying experiences, 20 classroom-level networks of bullying and friendship were constructed for 4 classrooms and 5 temporal points, from which 4 individual-level network measures were calculated. They included bully and victim centrality, popularity, and embeddedness in friendship networks. A series of mixed models for repeated measures were constructed to predict students' bully and victim centrality in bullying network at time t + 1. Compared to girls, boys were more likely to be both the bullies and victims. Lower self-esteem and higher family economic status contributed to victim centrality. Having parents married and living together predicted lower bully centrality. Higher educational level of parents predicted lower victim and bully centrality. Regarding the social network factors, students' bully centrality at t positively predicted their bully centrality at t + 1, whereas victim centrality predicted their subsequent victim centrality. Interaction effects between friendship network and bullying network were observed. Embeddedness in friendship network reduced victim centrality at t + 1 except for those students with low victim centrality at t. For those with high victim centrality at t, popularity increased their risk of physical victimization over time. Implications for research and practice are discussed. PMID:25199395

  16. From Student of Physics to Historian of Science: T.S. Kuhn's Education and Early Career, 1940-1958

    NASA Astrophysics Data System (ADS)

    Hufbauer, Karl

    2012-12-01

    I first show that Kuhn came to have doubts about physics soon after entering college but did not make up his mind to leave the discipline until 1947-1948 when a close association with Harvard's President James B. Conant convinced him of the desirability of an alternative career in the history of science. I go on to maintain that it was realistic for Kuhn to prepare for such a career in essentially autodidactic ways both because he enjoyed Conant's patronage and because he could expect that his credentials in physics would be an asset in this relatively young interdisciplinary specialty. I then suggest that it was through his work as a teacher, researcher, and journeyman gatekeeper in the history of science that Kuhn gradually came to identify with the field. Finally, I argue that his training in physics, his teaching of general-education courses, and his hopes of influencing current philosophy of science helped shape his early practice as a historian of science. By way of epilogue, I briefly consider Kuhn's path from his tenuring at Berkeley in 1958 to the appearance of The Structure of Scientific Revolutions in 1962.

  17. Diffraction by m-bonacci gratings

    NASA Astrophysics Data System (ADS)

    Monsoriu, Juan A.; Giménez, Marcos H.; Furlan, Walter D.; Barreiro, Juan C.; Saavedra, Genaro

    2015-11-01

    We present a simple diffraction experiment with m-bonacci gratings as a new interesting generalization of the Fibonacci ones. Diffraction by these non-conventional structures is proposed as a motivational strategy to introduce students to basic research activities. The Fraunhofer diffraction patterns are obtained with the standard equipment present in most undergraduate physics labs and are compared with those obtained with regular periodic gratings. We show that m-bonacci gratings produce discrete Fraunhofer patterns characterized by a set of diffraction peaks which positions are related to the concept of a generalized golden mean. A very good agreement is obtained between experimental and numerical results and the students’ feedback is discussed.

  18. X-Ray Diffraction.

    ERIC Educational Resources Information Center

    Smith, D. K.; Smith, K. L.

    1980-01-01

    Reviews applications in research and analytical characterization of compounds and materials in the field of X-ray diffraction, emphasizing new developments in applications and instrumentation in both single crystal and powder diffraction. Cites 414 references. (CS)

  19. Physics.

    ERIC Educational Resources Information Center

    Bromley, D. Allan

    1980-01-01

    The author presents the argument that the past few years, in terms of new discoveries, insights, and questions raised, have been among the most productive in the history of physics. Selected for discussion are some of the most important new developments in physics research. (Author/SA)

  20. Effect of initial curing on early strength and physical properties of a lightweight concrete

    SciTech Connect

    Al-Khaiat, H.; Haque, M.N.

    1998-06-01

    A 50 MPa 28-day cube compressive strength structural lightweight concrete of a fresh concrete density of 1800 kg/m{sup 3} was produced using Lytag coarse and fine aggregate. The long-term strength development and the durability characteristics of this lightweight concrete are being monitored in both the severe hot and dry and hot-coastal and salt-laden exposure conditions prevalent in Kuwait. The early results of the investigation suggest that the compressive strength of this concrete is less sensitive to lack of initial curing. However, depth of water penetration, which is indicative of the concrete`s permeability and hence durability, has been found to be more sensitive to the duration of initial curing even for the specimens exposed to the high-humidity seaside ambient conditions. The drying shrinkage of this concrete has been found to be more than 600 microstrain in the first 3 months` duration. Longer term durability data will be reported in due course.

  1. Probabilistic measurement of non-physical constructs during early childhood: Epistemological implications for advancing psychosocial science

    NASA Astrophysics Data System (ADS)

    Bezruczko, N.; Fatani, S. S.

    2010-07-01

    Social researchers commonly compute ordinal raw scores and ratings to quantify human aptitudes, attitudes, and abilities but without a clear understanding of their limitations for scientific knowledge. In this research, common ordinal measures were compared to higher order linear (equal interval) scale measures to clarify implications for objectivity, precision, ontological coherence, and meaningfulness. Raw score gains, residualized raw gains, and linear gains calculated with a Rasch model were compared between Time 1 and Time 2 for observations from two early childhood learning assessments. Comparisons show major inconsistencies between ratings and linear gains. When gain distribution was dense, relatively compact, and initial status near item mid-range, linear measures and ratings were indistinguishable. When Time 1 status was distributed more broadly and magnitude of change variable, ratings were unrelated to linear gain, which emphasizes problematic implications of ordinal measures. Surprisingly, residualized gain scores did not significantly improve ordinal measurement of change. In general, raw scores and ratings may be meaningful in specific samples to establish order and high/low rank, but raw score differences suffer from non-uniform units. Even meaningfulness of sample comparisons, as well as derived proportions and percentages, are seriously affected by rank order distortions and should be avoided.

  2. Dichroic Coherent Diffractive Imaging

    NASA Astrophysics Data System (ADS)

    Tripathi, Ashish

    Understanding electronic structure at nanometer resolution is crucial to understanding physics such as phase separation and emergent behavior in correlated electron materials. Nondestructive probes which have the ability to see beyond surfaces on nanometer length and sub-picosecond time scales can greatly enhance our understanding of these systems and will impact development of future technologies, such as magnetic storage. Polarized x-rays are an appealing choice of probe due to their penetrating power, elemental and magnetic specificity, and high spatial resolution. The resolution of traditional x-ray microscopy is limited by the nanometer precision required to fabricate x-ray optics. In this thesis, a novel approach to lensless imaging of an extended magnetic nanostructure is presented. We demonstrate this approach by imaging ferrimagnetic "maze" domains in a Gd/Fe multilayer with perpendicular anisotropy. A series of dichroic coherent diffraction patterns, ptychographically recorded, are numerically inverted using non-convex and non-linear optimization theory, and we follow the magnetic domain configuration evolution through part of its magnetization hysteresis loop by applying an external magnetic field. Unlike holographic methods, it does not require a reference wave or precision optics, and so is a far simpler experiment. In addition, it enables the imaging of samples with arbitrarily large spatial dimensions, at a spatial resolution limited solely by the coherent x-ray flux and wavelength. It can readily be extended to other non-magnetic systems that exhibit circular or linear dichroism. This approach is scalable to imaging with diffraction-limited resolution, a prospect rapidly becoming a reality in view of the new generation of phenomenally brilliant x-ray sources.

  3. Anomalous Diffraction in Crystallographic Phase Evaluation

    PubMed Central

    Hendrickson, Wayne A.

    2014-01-01

    X-ray diffraction patterns from crystals of biological macromolecules contain sufficient information to define atomic structures, but atomic positions are inextricable without having electron-density images. Diffraction measurements provide amplitudes, but the computation of electron density also requires phases for the diffracted waves. The resonance phenomenon known as anomalous scattering offers a powerful solution to this phase problem. Exploiting scattering resonances from diverse elements, the methods of multiwavelength anomalous diffraction (MAD) and single-wavelength anomalous diffraction (SAD) now predominate for de novo determinations of atomic-level biological structures. This review describes the physical underpinnings of anomalous diffraction methods, the evolution of these methods to their current maturity, the elements, procedures and instrumentation used for effective implementation, and the realm of applications. PMID:24726017

  4. Rationale for New York City’s Regulations on Nutrition, Physical Activity, and Screen Time in Early Child Care Centers

    PubMed Central

    Silver, Lynn D.; Kettel Khan, Laura; Leviton, Laura

    2014-01-01

    Childhood obesity is associated with health risks in childhood, and it increases the risk of adult obesity, which is associated with many chronic diseases. Therefore, implementing policies that may prevent obesity at young ages is important. In 2007, the New York City Department of Health and Mental Hygiene implemented new regulations for early childhood centers to increase physical activity, limit screen time, and provide healthful beverage offerings (ie, restrict sugar-sweetened beverages for all children, restrict whole milk for those older than 2 years, restrict juice to beverages that are 100% juice and limit serving of juice to only 6 ounces per day, and make water available and accessible at all times). This article explains why these amendments to the Health Code were created, how information about these changes was disseminated, and what training programs were used to help ensure implementation, particularly in high-need neighborhoods. PMID:25321633

  5. Industrial applications of neutron diffraction

    SciTech Connect

    Felcher, G.P.

    1989-01-01

    Neutron diffraction (or, to be more general, neutron scattering) is a most versatile and universal tool, which has been widely employed to probe the structure, the dynamics and the magnetism of condensed matter. Traditionally used for fundamental research in solid state physics, this technique more recently has been applied to problems of immediate industrial interest, as illustrated in examples covering the main fields of endeavour. 14 refs., 14 figs.

  6. Early Exposure to Environmental Chaos and Children’s Physical and Mental Health

    PubMed Central

    Coley, Rebekah Levine; Lynch, Alicia Doyle; Kull, Melissa

    2015-01-01

    Environmental chaos has been proposed as a central influence impeding children’s health and development, with the potential for particularly pernicious effects during the earliest years when children are most susceptible to environmental insults. This study evaluated a high-risk sample, following 495 low-income children living in poor urban neighborhoods from infancy to age 6. Longitudinal multilevel models tested the main tenets of the ecobiodevelopmental theory, finding that: (1) numerous distinct domains of environmental chaos were associated with children’s physical and mental health outcomes, including housing disorder, neighborhood disorder, and relationship instability, with no significant results for residential instability; (2) different patterns emerged in relation to the timing of exposure to chaos, with more proximal exposure most strongly associated with children’s functioning; and (3) the intensity of chaos also was a robust predictor of child functioning. Contrary to expectations, neither biological vulnerability (proxied through low birth weight status), maternal sensitivity, nor maternal distress moderated the role of chaos. Rather, maternal psychological distress functioned as a pathway through which environmental chaos was associated with children’s functioning. PMID:25844016

  7. Children’s Physic: Medical Perceptions and Treatment of Sick Children in Early Modern England, c. 1580–1720

    PubMed Central

    Newton, Hannah

    2015-01-01

    Summary Historians of medicine, childhood and paediatrics have often assumed that early modern doctors neither treated children, nor adapted their medicines to suit the peculiar temperaments of the young. Through an examination of medical textbooks and doctors’ casebooks, this article refutes these assumptions. It argues that medical authors and practising doctors regularly treated children, and were careful to tailor their remedies to complement the distinctive constitutions of children. Thus, this article proposes that a concept of ‘children’s physic’ existed in early modern England. This term refers to the notion that children were physiologically distinct, requiring special medical care. Children’s physic was rooted in the ancient traditions of Hippocratic and Galenic medicine: it was the child’s humoral make-up that underpinned all medical ideas about children’s bodies, minds, diseases and treatments. Children abounded in the humour blood, which made them humid and weak, and in need of medicines of a particularly gentle nature. PMID:26306061

  8. Design Principles for resilient cyber-physical Early Warning Systems - Challenges, Experiences, Design Patterns, and Best Practices

    NASA Astrophysics Data System (ADS)

    Gensch, S.; Wächter, J.; Schnor, B.

    2014-12-01

    Early warning systems (EWS) are safety-critical IT-infrastructures that serve the purpose of potentially saving lives or assets by observing real-world phenomena and issuing timely warning products to authorities and communities. An EWS consists of sensors, communication networks, data centers, simulation platforms, and dissemination channels. The components of this cyber-physical system may all be affected by both natural hazards and malfunctions of components alike. Resilience engineering so far has mostly been applied to safety-critical systems and processes in transportation (aviation, automobile), construction and medicine. Early warning systems need equivalent techniques to compensate for failures, and furthermore means to adapt to changing threats, emerging technology and research findings. We present threats and pitfalls from our experiences with the German and Indonesian tsunami early warning system, as well as architectural, technological and organizational concepts employed that can enhance an EWS' resilience. The current EWS is comprised of a multi-type sensor data upstream part, different processing and analysis engines, a decision support system, and various warning dissemination channels. Each subsystem requires a set of approaches towards ensuring stable functionality across system layer boundaries, including also institutional borders. Not only must services be available, but also produce correct results. Most sensors are distributed components with restricted resources, communication channels and power supply. An example for successful resilience engineering is the power capacity based functional management for buoy and tide gauge stations. We discuss various fault-models like cause and effect models on linear pathways, interaction of multiple events, complex and non-linear interaction of assumedly reliable subsystems and fault tolerance means implemented to tackle these threats.

  9. Harmonic diffractive lenses

    SciTech Connect

    Sweeney, D.W.; Sommargren, G.E.

    1995-05-10

    The harmonic diffractive lens is a diffractive imaging lens for which the optical path-length transition between adjacent facets is an integer multiple {ital m} of the design wavelength {lambda}{sub 0}. The total lens thickness in air is {ital m}{lambda}{sub 0}/({ital n} {minus} 1), which is {ital m} times thicker than the so-called modulo 2{pi} diffractive lens. Lenses constructed in this way have hybrid properties of both refractive and diffractive lenses. Such a lens will have a diffraction-limited, common focus for a number of discrete wavelengths across the visible spectrum. A 34.75-diopter, 6-mm-diameter lens is diamond turned in aluminum and replicated in optical materials. The sag of the lens is 23 {mu}m. Modulation transfer function measurements in both monochromatic and white light verify the performance of the lens. The lens approaches the diffraction limit for 10 discrete wavelengths across the visible spectrum.

  10. Physical and functional interactions between herpes simplex virus immediate-early proteins ICP4 and ICP27.

    PubMed Central

    Panagiotidis, C A; Lium, E K; Silverstein, S J

    1997-01-01

    The ordered expression of herpes simplex virus type 1 (HSV-1) genes, during the course of a productive infection, requires the action of the virus immediate-early regulatory proteins. Using a protein interaction assay, we demonstrate specific in vitro protein-protein interactions between ICP4 and ICP27, two immediate-early proteins of HSV-1 that are essential for virus replication. We map multiple points of contact between these proteins. Furthermore, by coimmunoprecipitation experiments, we demonstrate the following. (i) ICP4-ICP27 complexes are present in extracts from HSV-1 infected cells. (ii) ICP27 binds preferentially to less modified forms of ICP4, a protein that is extensively modified posttranslationally. We also demonstrate, by performing electrophoretic mobility shift assays and supershifts with monoclonal antibodies to ICP4 or ICP27, that both proteins are present in a DNA-protein complex with a noncanonical ICP4 binding site present in the HSV thymidine kinase (TK) gene. ICP4, in extracts from cells infected with ICP27-deficient viruses, is impaired in its ability to form complexes with the TK site but not with the canonical site from the alpha4 gene. However, ICP4 is able to form complexes with the TK probe, in the absence of ICP27, when overproduced in mammalian cells or expressed in bacteria. These data suggest that the inability of ICP4 from infected cell extracts to bind the TK probe in the absence of ICP27 does not reflect a requirement for the physical presence of ICP27 in the complex. Rather, they imply that ICP27 is likely to modulate the DNA binding activity of ICP4 by affecting its posttranslational modification status. Therefore, we propose that ICP27, in addition to its established role as a posttranscriptional regulator of virus gene expression, may also modulate transcription either through direct or indirect interactions with HSV regulatory regions, or through its ability to modulate the DNA binding activity of ICP4. PMID:8995681

  11. Knee pain during activities of daily living and its relationship with physical activity in patients with early and severe knee osteoarthritis.

    PubMed

    Fukutani, Naoto; Iijima, Hirotaka; Aoyama, Tomoki; Yamamoto, Yuko; Hiraoka, Masakazu; Miyanobu, Kazuyuki; Jinnouchi, Masashi; Kaneda, Eishi; Tsuboyama, Tadao; Matsuda, Shuichi

    2016-09-01

    This study aimed to investigate whether knee pain during various activities of daily living (ADLs) is associated with physical activity in patients with early and severe knee osteoarthritis (OA). We hypothesized that the painful ADLs associated with decreased physical activity differ according to disease severity. This cross-sectional study enrolled 270 patients with medial knee OA, assigned to either the early (Kellgren Lawrence [K/L] grade 1-2) or the severe group (K/L grade 3-4). Physical activity was assessed using a pedometer. Knee pain during six ADLs (waking up in the morning, walking on a flat surface, ascending stairs, etc.) was evaluated using a questionnaire. We performed multiple regression and quantile regression analysis to investigate whether knee pain during each ADL was associated with physical activity. In the early group, the more knee pain they experienced while ascending stairs, the lower their physical activity was (75th regression coefficient = -1033.70, P = 0.018). In the severe group, the more knee pain they experienced while walking on a flat surface or bending to the floor or standing up, the lower their physical activity was (unstandardized coefficients = -1850.87, P = 0.026; unstandardized coefficients = -2640.35, P = 0.010). Knee pain while ascending stairs and while walking on a flat surface or bending to the floor or standing up was a probable limiting factor for physical activity in early and severe knee OA, respectively. These findings suggested that a reduction in task-specific knee pain according to disease severity could improve physical activity levels. PMID:27041381

  12. Physical interaction between the herpes simplex virus type 1 immediate-early regulatory proteins ICP0 and ICP4.

    PubMed Central

    Yao, F; Schaffer, P A

    1994-01-01

    The herpes simplex virus type 1 immediate-early protein ICP0 enhances expression of a spectrum of viral genes alone and synergistically with ICP4. To test whether ICP0 and ICP4 interact physically, we performed far-Western blotting analysis of proteins from mock-, wild-type-, and ICP4 mutant virus-infected cells with in vitro-synthesized [35S]Met-labeled ICP0 and ICP4 as probes. The ICP4 and ICP0 polypeptides synthesized in vitro exhibited molecular weights similar to those of their counterparts in herpes simplex virus type 1-infected cells, and the in vitro-synthesized ICP4 was able to bind to a probe containing the ICP4 consensus binding site. Far-Western blotting experiments demonstrated that ICP0 interacts directly and specifically with ICP4 and with itself. To further define the interaction between ICP0 and ICP4, we generated a set of glutathione S-transferase (GST)-ICP0 fusion proteins that contain GST and either ICP0 N-terminal amino acids 1 to 244 or 1 to 394 or C-terminal amino acids 395 to 616 or 395 to 775. Using GST-ICP0 fusion protein affinity chromatography and in vitro-synthesized [35S]Met-labeled ICP0 and ICP4, ICP4 was shown to interact preferentially with the fusion protein containing ICP0 C-terminal amino acids 395 to 775, whereas ICP0 interacted efficiently with both the N-terminal GST-ICP0 fusion proteins and the C-terminal GST-ICP0 fusion proteins containing amino acids 395 to 775. Fusion protein affinity chromatography also demonstrated that the C-terminal 235 amino acid residues of ICP4 are important for efficient interaction with ICP0. Collectively, these results reveal a direct and specific physical interaction between ICP0 and ICP4. Images PMID:7966607

  13. A diffractive mechanism of focusing.

    PubMed

    Case, W B; Sadurni, E; Schleich, W P

    2012-12-01

    We examine the free time evolution of a rectangular one dimensional Schrödinger wave packet of constant phase during the early stage which in the paraxial wave approximation is identical to the diffraction of a scalar field from a single slit. Our analysis, based on numerics and the Cornu spiral reveals considerable intricate detail behavior in the density and phase of the wave. We also point out a concentration of the intensity that occurs on axis and propose a new measure of width that expresses this concentration. PMID:23262675

  14. Diffraction by cold atoms

    NASA Astrophysics Data System (ADS)

    Strauch, F.; Gomer, V.; Schadwinkel, H.; Ueberholz, B.; Haubrich, D.; Meschede, D.

    1998-01-01

    We have observed diffraction of a laser probe beam by a trapped sample of cold atoms. The effect is only visible in the vicinity of a resonance line. The observed diffraction pattern arises from interference of the incident and scattered light wave, allowing reconstruction of geometric properties of the trapped sample from the holographic record.

  15. Diffraction Results from CDF

    SciTech Connect

    Goulianos, Konstantin

    2012-04-01

    We present final results by the CDF II collaboration on diffractive W and Z production, report on the status of ongoing analyses on diffractive dijet production and on rapidity gaps between jets, and briefly summarize results obtained on exclusive production pointing to their relevance to calibrating theoretical models used to predict exclusive Higgs-boson production at the LHC.

  16. Phononic crystal diffraction gratings

    NASA Astrophysics Data System (ADS)

    Moiseyenko, Rayisa P.; Herbison, Sarah; Declercq, Nico F.; Laude, Vincent

    2012-02-01

    When a phononic crystal is interrogated by an external source of acoustic waves, there is necessarily a phenomenon of diffraction occurring on the external enclosing surfaces. Indeed, these external surfaces are periodic and the resulting acoustic diffraction grating has a periodicity that depends on the orientation of the phononic crystal. This work presents a combined experimental and theoretical study on the diffraction of bulk ultrasonic waves on the external surfaces of a 2D phononic crystal that consists of a triangular lattice of steel rods in a water matrix. The results of transmission experiments are compared with theoretical band structures obtained with the finite-element method. Angular spectrograms (showing frequency as a function of angle) determined from diffraction experiments are then compared with finite-element simulations of diffraction occurring on the surfaces of the crystal. The experimental results show that the diffraction that occurs on its external surfaces is highly frequency-dependent and has a definite relation with the Bloch modes of the phononic crystal. In particular, a strong influence of the presence of bandgaps and deaf bands on the diffraction efficiency is found. This observation opens perspectives for the design of efficient phononic crystal diffraction gratings.

  17. Unaccompanied refugee minors' early life narratives of physical abuse from caregivers and teachers in their home countries.

    PubMed

    Skårdalsmo Bjørgo, Envor M; Jensen, Tine K

    2015-10-01

    The early life narratives of 34 unaccompanied refugee minors, especially their reports of interpersonal violence, were analyzed using Interpretative Phenomenological Analysis (IPA). The youth originated from eight countries, with Afghanistan, Eritrea, and Sri Lanka being the most frequent origins, and they arrived to Norway before the age of 15. Four of these youth were girls. The physical violence took place at home and/or at school and could be extremely harsh. Approximately half of the youth expressed some type of ambivalence toward the perpetrator. In analyzing how the youth understood the reasons for violence two categories of internal and three categories of external attributions were found. Several of the youth blamed their own behavior for the abuse, although such internal attributions were frequently combined with external attributions. Some different patterns of attributions emerged between home and school violence. Most of the youth placed the blame for school violence on their own behavior or that violence was part of normal school discipline. For violence at home there was a tendency to place more blame on the perpetrator (mostly fathers). Possible long-term consequences of the experiences and the different attributional styles as well as implications of the findings are discussed. Professionals should assess refugee children for interpersonal violence experiences as well as for other experiences in their home country. PMID:26307532

  18. Theory of hard diffraction and rapidity gaps

    SciTech Connect

    Del Duca, V.

    1996-02-01

    In this talk we review the models describing the hard diffractive production of jets or more generally high-mass states in presence of rapidity gaps in hadron-hadron and lepton-hadron collisions. By rapidity gaps we mean regions on the lego plot in (pseudo)-rapidity and azimuthal angle where no hadrons are produced, between the jet(s) and an elastically scattered hadron (single hard diffraction) or between two jets (double hard diffraction). {copyright} {ital 1996 American Institute of Physics.}

  19. The Role of Occupational Therapists and Physical Therapists in Elementary School System Early Intervening Services and Response to Intervention: A Case Report

    ERIC Educational Resources Information Center

    Reeder, Deborah L.; Arnold, Sandra H.; Jeffries, Lynn M.; McEwen, Irene R.

    2011-01-01

    The Individuals with Disabilities Improvement Act and No Child Left Behind Act broadened the roles of occupational therapists (OTs) and physical therapists (PTs) to include therapist participation in early intervening services including response to intervention (RTI). This case report describes one school district's inclusion of OT and PT in the…

  20. The Differential Impacts of Early Physical and Sexual Abuse and Internalizing Problems on Daytime Cortisol Rhythm in School-Aged Children

    ERIC Educational Resources Information Center

    Cicchetti, Dante; Rogosch, Fred A.; Gunnar, Megan R.; Toth, Sheree L.

    2010-01-01

    The impact of early physical and sexual abuse (EPA/SA) occurring in the first 5 years of life was investigated in relation to depressive and internalizing symptomatology and diurnal cortisol regulation. In a summer camp context, school-aged maltreated (n = 265) and nonmaltreated (n = 288) children provided morning and late afternoon saliva samples…

  1. Exploring Daily Physical Activity and Nutrition Patterns in Early Learning Settings: Snapshots of Young Children in Head Start, Primary, and After-School Settings

    ERIC Educational Resources Information Center

    Stegelin, Dolores A.; Anderson, Denise; Kemper, Karen; Wagner, Jennifer; Evans, Katharine

    2014-01-01

    The purpose of this research project was to gain a greater understanding of daily routines of 4-7 year olds regarding physical activity and nutrition practices in typical early learning environments. The settings selected for this observational study included Head Start, primary, and after-school learning environments in a city in the southeast.…

  2. From Policy to Practice: A Program Logic Approach to Describing the Implementation of Early Intervention Services for Children with Physical Disability

    ERIC Educational Resources Information Center

    Ziviani, Jenny; Darlington, Yvonne; Feeney, Rachel; Head, Brian

    2011-01-01

    The benefits of providing early intervention services (including multidisciplinary therapy and family support) for children with physical disabilities and their families are widely acknowledged. Evidence, however, of their efficacy is not well documented. Furthermore, many studies fail to adequately describe the programs being evaluated and how…

  3. Exploring direct and indirect influences of physical work environment on job satisfaction for early-career registered nurses employed in hospitals.

    PubMed

    Djukic, Maja; Kovner, Christine T; Brewer, Carol S; Fatehi, Farida; Greene, William H

    2014-08-01

    We explored direct and indirect influences of physical work environment on job satisfaction in a nationally representative sample of 1,141 early-career registered nurses. In the fully specified model, physical work environment had a non-significant direct effect on job satisfaction. The path analysis used to test multiple indirect effects showed that physical work environment had a positive indirect effect (p < .05) on job satisfaction through ten variables: negative affectivity, variety, workgroup cohesion, nurse-physician relations, quantitative workload, organizational constraints, distributive justice, promotional opportunity, local and non-local job opportunities. The findings make important contributions to the understanding of the relationship between physical work environment and job satisfaction. The results can inform health care leaders' insight about how physical work environment influences nurses' job satisfaction. PMID:24985551

  4. Calculating incoherent diffraction MTF

    NASA Astrophysics Data System (ADS)

    Friedman, Melvin; Vizgaitis, Jay

    2008-04-01

    The incoherent diffraction MTF plays an increasingly important role in the range performance of imaging systems as the wavelength increases and the optical aperture decreases. Accordingly, all NVESD imager models have equations that describe the incoherent diffraction MTF of a circular entrance pupil. NVThermIP, a program which models thermal imager range performance, has built in equations which analytically model the incoherent diffraction MTF of a circular entrance pupil and has a capability to input a table that describes the MTF of other apertures. These can be calculated using CODE V, which can numerically calculate the incoherent diffraction MTF in the vertical or horizontal direction for an arbitrary aperture. However, we are not aware of any program that takes as input a description of the entrance pupil and analytically outputs equations that describe the incoherent diffraction MTF. This work explores the effectiveness of Mathematica to analytically and numerically calculate the incoherent diffraction MTF for an arbitrary aperture. In this work, Mathematica is used to analytically and numerically calculate the incoherent diffraction MTF for a variety of apertures and the results are compared with CODE V calculations.

  5. Multilayer dielectric diffraction gratings

    DOEpatents

    Perry, Michael D.; Britten, Jerald A.; Nguyen, Hoang T.; Boyd, Robert; Shore, Bruce W.

    1999-01-01

    The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described.

  6. Multilayer dielectric diffraction gratings

    DOEpatents

    Perry, M.D.; Britten, J.A.; Nguyen, H.T.; Boyd, R.; Shore, B.W.

    1999-05-25

    The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described. 7 figs.

  7. Effect of supervised exercise intervention on metabolic risk factors and physical fitness in Chinese obese children in early puberty.

    PubMed

    Chang, C; Liu, W; Zhao, X; Li, S; Yu, C

    2008-03-01

    The aim of this paper was to study the effect of long-term supervised exercise-induced weight maintenance on metabolic risk factors and physical fitness in obese children in early puberty. A total of 49 obese children aged 12-14 years were divided into control and exercise groups. The children in the exercise group accepted exercise intervention supervised by a professional sports teacher for 9 of the 12 months. All participants in both groups received health education once every 3 months. Anthropometry and fasting serum lipids, glucose, insulin and homeostatic model assessment for insulin resistance (HOMA-IR) were measured at months 0, 3, 9, 12 of the intervention. Physical fitness was determined before and after intervention. After the intervention (i) BMI was reduced by 0.6 (P < 0.05) in the exercise group, but increased by 0.5 (P < 0.05) in the control group, compared with the pre-intervention level at the end of 9-month intervention; (ii) Triglyceride levels in the exercise group significantly decreased by 23.1% by 3 months (P < 0.05), and by 30.2% after 9 months (P < 0.05), but increased by 50% (P < 0.05) in the control group; high density lipoprotein-cholesterol (HDL-C) decreased more by 35% (P < 0.05) in the controls than in the exercise group (P < 0.05); (iii) Fasting serum glucose, insulin level and HOMA-IR decreased, respectively, by 23.1%, 36.6% and 48.5% in the exercise group at 9 months (P < 0.05), whereas glucose levels increased by 10.9% (P < 0.05) in the control group; (iv) Exercise performance, such as upper- and lower-limb strength, flexibility and endurance, were enhanced by 17.9%, 12.3%, 22.3% and 20.4% (P < 0.01), respectively and (v) At 12 months, i.e. 3 months after terminating the supervised exercise, serum triglycerides, glucose, insulin and HOMA-IR level all returned to the pre-intervention level. Supervised decrement exercise can effectively slow the progress of obesity, improve insulin sensitivity and metabolic risk factors, but once

  8. Submicron X-ray diffraction

    SciTech Connect

    MacDowell, Alastair; Celestre, Richard; Tamura, Nobumichi; Spolenak, Ralph; Valek, Bryan; Brown, Walter; Bravman, John; Padmore, Howard; Batterman, Boris; Patel, Jamshed

    2000-08-17

    At the Advanced Light Source in Berkeley the authors have instrumented a beam line that is devoted exclusively to x-ray micro diffraction problems. By micro diffraction they mean those classes of problems in Physics and Materials Science that require x-ray beam sizes in the sub-micron range. The instrument is for instance, capable of probing a sub-micron size volume inside micron sized aluminum metal grains buried under a silicon dioxide insulating layer. The resulting Laue pattern is collected on a large area CCD detector and automatically indexed to yield the grain orientation and deviatoric (distortional) strain tensor of this sub-micron volume. A four-crystal monochromator is then inserted into the beam, which allows monochromatic light to illuminate the same part of the sample. Measurement of diffracted photon energy allows for the determination of d spacings. The combination of white and monochromatic beam measurements allow for the determination of the total strain/stress tensor (6 components) inside each sub-micron sized illuminated volume of the sample.

  9. Hard diffraction at CDF

    SciTech Connect

    Melese, P.L.; CDF Collaboration

    1996-07-01

    We present new evidence for events with a rapidity gap between jets in {bar p}-p collisions at {radical}s = 1.8 TeV based on data collected by triggering the Collider Detector at Fermilab on two high transverse momentum forward jets and results of a search for diffractive W{+-} and dijet production where diffraction is tagged by the rapidity gap technique. We also present the results of a search for diffractive dijets using data collected by triggering on a very forward particle in the recently installed roman-pot detectors. The dijet events exhibit additional diffractive characteristics such as rapidity gaps and boosted center of mass system, however the recoil antiproton measured in the roman-pots is in a regime in which the non- pomeron contribution is significant.

  10. Physical Activity Levels in Chinese One-Year-Old Children and Their Parents, an Early STOPP China Study

    PubMed Central

    Hagströmer, Maria; Xiong, Yuelin; Zhang, Lanlan; Zhang, Jianduan; Marcus, Claude

    2016-01-01

    Background Physical activity (PA) is associated with health benefits, already in childhood. However, little is known about actual levels, patterns and gender differences in PA level in very young children. This study examines Chinese one-year-old children and their parents’ PA levels and patterns, and assesses the correlations between children’s PA level and gender, body mass index standard deviation score (BMI SDS), parental BMI and parental PA level. Methods Data from 123 families participating in the Early STOPP China study were used. Families were recruited based on parental BMI and were classified as either high-risk or low-risk of obesity. Parents and children wore an ActiGraph GT3X+ to assess the average PA levels. PA levels and hourly patterns during weekdays and weekends were examined as were correlations with gender, BMI SDS, parental BMI and parental PA levels. Results There were no significant differences in children’s averaged PA between risk groups, genders, or between weekdays and weekends. Children’s peak average activity level was at 7 pm and they were least active at 3 pm (p<0.001). Both mothers and fathers demonstrated a similar PA pattern as their children, although paternal PA level was consistently lower than that of mothers and children. No significant association was found between children’s PA and their gender, BMI SDS, parental BMI or paternal PA levels. Maternal PA was found positively associated with child PA (p<0.05). Conclusion PA in one-year-old Chinese children vary over the day but weekdays and weekends are similar. At this age, children’s PA is not related to gender, BMI SDS, parental BMI or paternal PA. Larger scale studies with more contextual information are needed to improve the understanding of our findings. PMID:27078684

  11. Modeling and simulation of blast-induced, early-time intracranial wave physics leading to traumatic brain injury.

    SciTech Connect

    Ford, Corey C.; Taylor, Paul Allen

    2008-02-01

    The objective of this modeling and simulation study was to establish the role of stress wave interactions in the genesis of traumatic brain injury (TBI) from exposure to explosive blast. A high resolution (1 mm{sup 3} voxels), 5 material model of the human head was created by segmentation of color cryosections from the Visible Human Female dataset. Tissue material properties were assigned from literature values. The model was inserted into the shock physics wave code, CTH, and subjected to a simulated blast wave of 1.3 MPa (13 bars) peak pressure from anterior, posterior and lateral directions. Three dimensional plots of maximum pressure, volumetric tension, and deviatoric (shear) stress demonstrated significant differences related to the incident blast geometry. In particular, the calculations revealed focal brain regions of elevated pressure and deviatoric (shear) stress within the first 2 milliseconds of blast exposure. Calculated maximum levels of 15 KPa deviatoric, 3.3 MPa pressure, and 0.8 MPa volumetric tension were observed before the onset of significant head accelerations. Over a 2 msec time course, the head model moved only 1 mm in response to the blast loading. Doubling the blast strength changed the resulting intracranial stress magnitudes but not their distribution. We conclude that stress localization, due to early time wave interactions, may contribute to the development of multifocal axonal injury underlying TBI. We propose that a contribution to traumatic brain injury from blast exposure, and most likely blunt impact, can occur on a time scale shorter than previous model predictions and before the onset of linear or rotational accelerations traditionally associated with the development of TBI.

  12. Reflective diffraction grating

    DOEpatents

    Lamartine, Bruce C.

    2003-06-24

    Reflective diffraction grating. A focused ion beam (FIB) micromilling apparatus is used to store color images in a durable medium by milling away portions of the surface of the medium to produce a reflective diffraction grating with blazed pits. The images are retrieved by exposing the surface of the grating to polychromatic light from a particular incident bearing and observing the light reflected by the surface from specified reception bearing.

  13. Powder Diffraction: By Decades

    NASA Astrophysics Data System (ADS)

    David, William I. F.

    This introductory chapter reviews the first 100 years of powder diffraction, decade by decade, from the earliest X-ray powder diffraction measurements of the crystal structure of graphite through to the diversity and complexity of twenty-first century powder diffraction. Carbon features as an illustrative example throughout the discussion of these ten decades from graphite and the disorder of carbon black through to lonsdaleite, the elusive hexagonal polymorph of diamond, and C60, the most symmetrical of molecules. Electronics and computing have played a leading role in the development of powder diffraction, particularly over the past 60 years, and the Moore's Law decade-by-decade rise in computing power is clear in the increasing complexity of powder diffraction experiments and material systems that can be studied. The chapter concludes with a final discussion of decades - the four decades of length-scale from the ångstrom to the micron that not only represent the domain of powder diffraction but are also the distances that will dominate twenty-first century science and technology.

  14. Physical Activity, Physical Self-Concept, and Health-Related Quality of Life of Extreme Early and Late Maturing Adolescent Girls

    ERIC Educational Resources Information Center

    Cumming, Sean P.; Sherar, Lauren B.; Smart, Joanna E. Hunter; Rodrigues, Aristides M. M.; Standage, Martyn; Gillison, Fiona B.; Malina, Robert M.

    2012-01-01

    In this study we tested for differences in physical activity (PA), physical self-concept, and health-related quality of life (HRQoL) between the least and most biologically mature adolescent females within their respective chronological and academic year groups. A total of 222 British female adolescents aged 10 to 14 years (X[bar] age = 12.7…

  15. Analysis of North Carolina Community College Early Childhood Education Coursework on Nutrition, Health, and Physical Activity. Early Childhood Professional Development Report, Volume 1, Number 1

    ERIC Educational Resources Information Center

    Dunst, Carl J.; Raab, Melinda; Hamby, Deborah W.; Long, Anna Lauren

    2015-01-01

    The results from a content analysis of coursework required and offered at the 58 North Carolina Community Colleges to obtain an Associate in Applied Sciences Degree in early childhood education are described. The analyses were conducted to determine the likelihood that the courses could include content knowledge or practice on 12 infant and child…

  16. Hard diffraction and deep inelastic scattering

    SciTech Connect

    Bjorken, J.D.

    1994-04-01

    Since the advent of hard-collision physics, the study of diffractive processes - shadow physics - has been less prominent than before. However, there is now a renewed interest in the subject, especially in that aspect which synthesizes the short-distance, hard-collision phenomena with the classical physics of large rapidity-gaps. This is especially stimulated by the recent data on deep-inelastic scattering from HERA, as well as the theoretical work which relates to it. The word diffraction is sometimes used by high-energy physicists in a loose way. The author defines this term to mean: A diffractive process occurs if and only if there is a large rapidity gap in the produced-particle phase space which is not exponentially suppressed. Here a rapidity gap means essentially no hadrons produced into the rapidity gap (which operates in the {open_quotes}lego{close_quotes} phase-space of pseudo-rapidity and azimuthal angle). And non-exponential suppression implies that the cross-section for creating a gap with width {Delta}{eta} does not have a power-law decrease with increasing subenergy s=e{sup {Delta}{eta}}, but behaves at most like some power of pseudorapidity {Delta}{eta}{approx}log(s). The term hard diffraction shall simply refer to those diffractive process which have jets in the final-state phase-space.

  17. Multipath analysis diffraction calculations

    NASA Technical Reports Server (NTRS)

    Statham, Richard B.

    1996-01-01

    This report describes extensions of the Kirchhoff diffraction equation to higher edge terms and discusses their suitability to model diffraction multipath effects of a small satellite structure. When receiving signals, at a satellite, from the Global Positioning System (GPS), reflected signals from the satellite structure result in multipath errors in the determination of the satellite position. Multipath error can be caused by diffraction of the reflected signals and a method of calculating this diffraction is required when using a facet model of the satellite. Several aspects of the Kirchhoff equation are discussed and numerical examples, in the near and far fields, are shown. The vector form of the extended Kirchhoff equation, by adding the Larmor-Tedone and Kottler edge terms, is given as a mathematical model in an appendix. The Kirchhoff equation was investigated as being easily implemented and of good accuracy in the basic form, especially in phase determination. The basic Kirchhoff can be extended for higher accuracy if desired. A brief discussion of the method of moments and the geometric theory of diffraction is included, but seems to offer no clear advantage in implementation over the Kirchhoff for facet models.

  18. The Differential Impacts of Early Physical and Sexual Abuse and Internalizing Problems on Daytime Cortisol Rhythm in School-Aged Children

    PubMed Central

    Cicchetti, Dante; Rogosch, Fred A.; Gunnar, Megan R.; Toth, Sheree L.

    2009-01-01

    The impact of early physical and sexual abuse (EPA/SA) occurring in the first five years of life was investigated in relation to depressive and internalizing symptomatology and diurnal cortisol regulation. In a summer camp context, school-aged maltreated (n = 265) and nonmaltreated (n = 288) children provided morning and late afternoon saliva samples on five consecutive days. Child self-report and adult observer reports of child internalizing and depressive symptoms were obtained. Children experiencing EPA/SA and high depressive or internalizing symptoms uniquely exhibited an attenuated diurnal decrease in cortisol, indicative of neuroendocrine dysregulation. These results were specific to EPA/SA, rather than later onset physical or sexual abuse or early occurring neglect or emotional maltreatment. PMID:20331666

  19. Optical diffractive elements for medical applications

    NASA Astrophysics Data System (ADS)

    Mikula, Grzegorz; Kolodziejczyk, Andrzej; Makowski, Michal; Sypek, Maciej

    2005-09-01

    We present a class of diffractive elements that can be used in medical applications. We describe their physical properties, in particular the point spread functions and modulation transfer functions. Our analyses consist of the detailed numerical simulations. The obtained results correspond to the different setup parameters and confirm usefulness of such structures in medical aspect, especially in presbyopia treatment.

  20. Conference on Early Mars: Geologic and Hydrologic Evolution, Physical and Chemical Environments, and the Implications for Life

    NASA Technical Reports Server (NTRS)

    Clifford, S. M. (Editor); Treiman, A. H. (Editor); Newsom, H. E. (Editor); Farmer, J. D. (Editor)

    1997-01-01

    Topics considered include: Geology alteration and life in an extreme environment; developing a chemical code to identify magnetic biominerals; effect of impacts on early Martin geologic evolution; spectroscopic identification of minerals in Hematite-bearing soils and sediments; exopaleontology and the search for a Fossil record on Mars; geochemical evolution of the crust of Mars; geological evolution of the early earth;solar-wind-induced erosion of the Mars atmosphere. Also included geological evolution of the crust of Mars.

  1. Trends in brain oxygenation during mental and physical exercise measured using near-infrared spectroscopy (NIRS): potential for early detection of Alzheimer's disease

    NASA Astrophysics Data System (ADS)

    Allen, Monica S.; Allen, Jeffery W.; Mikkilineni, Shweta; Liu, Hanli

    2005-04-01

    Motivation: Early diagnosis of Alzheimer's disease (AD) is crucial because symptoms respond best to available treatments in the initial stages of the disease. Recent studies have shown that marked changes in brain oxygenation during mental and physical tasks can be used for noninvasive functional brain imaging to detect Alzheimer"s disease. The goal of our study is to explore the possibility of using near infrared spectroscopy (NIRS) and mapping (NIRM) as a diagnostic tool for AD before the onset of significant morphological changes in the brain. Methods: A 16-channel NIRS brain imager was used to noninvasively measure spatial and temporal changes in cerebral hemodynamics induced during verbal fluency task and physical activity. The experiments involved healthy subjects (n = 10) in the age range of 25+/-5 years. The NIRS signals were taken from the subjects' prefrontal cortex during the activities. Results and Conclusion: Trends of oxygenated and deoxygenated hemoglobin in the prefrontal cortex of the brain were observed. During the mental stimulation, the subjects showed significant increase in oxygenated hemoglobin [HbO2] with a simultaneous decrease in deoxygenated hemoglobin [Hb]. However, physical exercise caused a rise in levels of HbO2 with small variations in Hb. This study basically demonstrates that NIRM taken from the prefrontal cortex of the human brain is sensitive to both mental and physical tasks and holds potential to serve as a diagnostic means for early detection of Alzheimer's disease.

  2. DIFFRACTION FROM MODEL CRYSTALS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although calculating X-ray diffraction patterns from atomic coordinates of a crystal structure is a widely available capability, calculation from non-periodic arrays of atoms has not been widely applied to cellulose. Non-periodic arrays result from modeling studies that, even though started with at...

  3. Calculating cellulose diffraction patterns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although powder diffraction of cellulose is a common experiment, the patterns are not widely understood. The theory is mathematical, there are numerous different crystal forms, and the conventions are not standardized. Experience with IR spectroscopy is not directly transferable. An awful error, tha...

  4. Diffractive hard scattering

    SciTech Connect

    Berger, E.L.; Collins, J.C.; Soper, D.E.; Sterman, G.

    1986-03-01

    I discuss events in high energy hadron collisions that contain a hard scattering, in the sense that very heavy quarks or high P/sub T/ jets are produced, yet are diffractive, in the sense that one of the incident hadrons is scattered with only a small energy loss. 8 refs.

  5. Friendship conflict and the development of generalized physical aggression in the early school years: a genetically informed study of potential moderators.

    PubMed

    Salvas, Marie-Claude; Vitaro, Frank; Brendgen, Mara; Dionne, Ginette; Tremblay, Richard E; Boivin, Michel

    2014-06-01

    Several authors consider high and frequent conflicts between friends during childhood as a serious risk for subsequent conduct problems such as generalized physical aggression toward others (e.g., Kupersmidt, Burchinal, & Patterson, 1995; Sebanc, 2003). Although it seems logical to assume that friendship conflict could have some negative consequences on children's behaviors, some scholars have suggested that a certain amount of conflict between friends may actually promote social adjustment (e.g., Laursen & Pursell, 2009). The aim of this study was to investigate the role of friendship conflict in regard to the development of generalized physical aggression toward others in the early school years (i.e., from kindergarten to Grade 1), as well as the moderating role of relational (i.e., shared positive affect and dyadic conflict resolution skills) and personal (i.e., children's sex and genetic liability for aggression) characteristics in this context. The sample included 745 twins assessed through teacher, peer, child, and friend ratings in kindergarten and Grade 1. Friendship conflict in kindergarten was linearly related to an increase in boys' but not girls' generalized physical aggression. However, shared positive affect and conflict resolution skills mitigated the prospective associations between friendship conflict and generalized physical aggression. These results were independent of children's sex, genetic risk for physical aggression, and initial levels of generalized physical aggression in kindergarten. Fostering a positive relationship between friends at school entry may buffer against the risk associated with experiencing friendship conflict. PMID:24684716

  6. The Early Childhood Aggression Curve: Development of Physical Aggression in 10- to 50-Month-Old Children

    ERIC Educational Resources Information Center

    Alink, Lenneke R. A.; Mesman, Judi; van Zeijl, Jantien; Stolk, Mirjam N.; Juffer, Femmie; Koot, Hans M.; Bakermans-Kranenburg, Marian J.; van I Jzendoorn, Marinus H.

    2006-01-01

    This study examines the prevalence, stability, and development of physical aggression, as reported by mothers and fathers, in a sample of children initially recruited at 12, 24, and 36 months (N=2,253) and in a subsample followed up 1 year later (n=271) in a cross-sequential design. Physical aggression occurred in 12-month-olds, but significantly…

  7. Mothers' Perceived Physical Health during Early and Middle Childhood: Relations with Child Developmental Delay and Behavior Problems

    ERIC Educational Resources Information Center

    Eisenhower, Abbey; Blacher, Jan; Baker, Bruce L.

    2013-01-01

    The self-perceived physical health of mothers raising children with developmental delay (DD; N = 116) or typical development (TD; N = 129) was examined across child ages 3-9 years, revealing three main findings. First, mothers of children with DD experienced poorer self-rated physical health than mothers of children with TD at each age. Latent…

  8. Introduction to Diffraction in Materials Science and Engineering

    NASA Astrophysics Data System (ADS)

    Krawitz, Aaron D.

    2001-04-01

    Fundamentals and practical applications of diffraction for researchers, engineers, and students Materials science relies heavily on diffraction for the analysis of materials. Introduction to Diffraction in Materials Science and Engineering is a survey of the practical aspects of this valuable tool. Though it contains basic discussion of the theory and physics of diffraction, this book emphasizes understanding and the practical application of diffraction in materials science-making it a valuable text and resource for students, professionals, and researchers. Designed as a teaching and self-study text, this resource begins with a treatment of the fundamentals of crystallography and crystal structure and its importance in diffraction before moving on to cover important aspects of diffraction applications. Numerous examples and problems at the end of each chapter, including critical thinking questions, make this an excellent tool for learning and understanding. The book includes treatments of: * Basics of crystallography * Geometrical representation of crystals and reciprocal space * X-rays and neutrons * Structure factors and intensity * Powder diffraction * Qualitative (Powder Diffraction File) and quantitative phase analysis * Use of the International Tables for more complex structures and the Reitveld method * Residual stress * Introductions to texture, small diffracting units, and long-range order Aaron Krawitz provides both a practical introduction to diffraction that suits the needs of students and a resource for professionals already at work in materials science or engineering who want to utilize the power of diffraction in the study of materials.

  9. A policy-driven multifaceted approach for early childhood physical fitness promotion: impacts on body composition and physical fitness in young Chinese children

    PubMed Central

    2014-01-01

    Background The prevalence of obesity increased while certain measures of physical fitness deteriorated in preschool children in China over the past decade. This study tested the effectiveness of a multifaceted intervention that integrated childcare center, families, and community to promote healthy growth and physical fitness in preschool Chinese children. Methods This 12-month study was conducted using a quasi-experimental pretest/posttest design with comparison group. The participants were 357 children (mean age = 4.5 year) enrolled in three grade levels in two childcare centers in Beijing, China. The intervention included: 1) childcare center intervention (physical activity policy changes, teacher training, physical education curriculum and food services training), 2) family intervention (parent education, internet website for support, and family events), and 3) community intervention (playground renovation and community health promotion events). The study outcome measures included body composition (percent body fat, fat mass, and muscle mass), Body Mass Index (BMI) and BMI z-score and physical fitness scores in 20-meter agility run (20M-AR), broad jump for distance (BJ), timed 10-jumps, tennis ball throwing (TBT), sit and reach (SR), balance beam walk (BBW), 20-meter crawl (20M-C)), 30-meter sprint (30M-S)) from a norm referenced test. Measures of process evaluation included monitoring of children’s physical activity (activity time and intensity) and food preparation records, and fidelity of intervention protocol implementation. Results Children in the intervention center significantly lowered their body fat percent (−1.2%, p < 0.0001), fat mass (−0.55 kg, p <0.0001), and body weight (0.36 kg, p <0.02) and increased muscle mass (0.48 kg, p <0.0001), compared to children in the control center. They also improved all measures of physical fitness except timed 10-jumps (20M-AR: −0.74 seconds, p < 0.0001; BJ: 8.09 cm, p < 0.0001; TBT: 0

  10. Naturally occurring changes in time spent watching television are inversely related to frequency of physical activity during early adolescence.

    PubMed

    Motl, Robert W; McAuley, Edward; Birnbaum, Amanda S; Lytle, Leslie A

    2006-02-01

    In this longitudinal study, we examined the relationship between changes in time spent watching television and playing video games with frequency of leisure-time physical activity across a 2-year period among adolescent boys and girls (N=4594). Latent growth modelling indicated that a decrease in time spent watching television was associated with an increase in frequency of leisure-time physical activity. That relationship was strong in magnitude and independent of sex, socioeconomic status, smoking, and the value participants placed on health, appearance, and achievement. Our results encourage the design of interventions that reduce television watching as a possible means of increasing adolescent physical activity. PMID:16338428

  11. Light-scattering theory of diffraction.

    PubMed

    Guo, Wei

    2010-03-01

    Since diffraction is a scattering process in principle, light propagation through one aperture in a screen is discussed in the light-scattering theory. Through specific calculation, the expression of the electric field observed at an observation point is obtained and is used not only to explain why Kirchhoff's diffraction theory is a good approximation when the screen is both opaque and sufficiently thin but also to demonstrate that the mathematical and physical problems faced by Kirchhoff's theory are avoided in the light-scattering theory. PMID:20208939

  12. Colored Diffraction Catastrophes

    NASA Astrophysics Data System (ADS)

    Berry, M. V.; Klein, S.

    1996-03-01

    On fine scales, caustics produced with white light show vividly colored diffraction fringes. For caustics described by the elementary catastrophes of singularity theory, the colors are characteristic of the type of singularity. We study the diffraction colors of the fold and cusp catastrophes. The colors can be simulated computationally as the superposition of monochromatic patterns for different wavelengths. Far from the caustic, where the luminosity contrast is negligible, the fringe colors persist; an asymptotic theory explains why. Experiments with caustics produced by refraction through irregular bathroom-window glass show good agreement with theory. Colored fringes near the cusp reveal fine lines that are not present in any of the monochromatic components; these lines are explained in terms of partial decoherence between rays with widely differing path differences.

  13. Central diffraction at ALICE

    NASA Astrophysics Data System (ADS)

    Lämsä, J. W.; Orava, R.

    2011-02-01

    The ALICE experiment is shown to be well suited for studies of exclusive final states from central diffractive reactions. The gluon-rich environment of the central system allows detailed QCD studies and searches for exotic meson states, such as glueballs, hybrids and new charmonium-like states. It would also provide a good testing ground for detailed studies of heavy quarkonia. Due to its central barrel performance, ALICE can accurately measure the low-mass central systems with good purity. The efficiency of the Forward Multiplicity Detector (FMD) and the Forward Shower Counter (FSC) system for detecting rapidity gaps is shown to be adequate for the proposed studies. With this detector arrangement, valuable new data can be obtained by tagging central diffractive processes.

  14. Colored diffraction catastrophes.

    PubMed Central

    Berry, M V; Klein, S

    1996-01-01

    On fine scales, caustics produced with white light show vividly colored diffraction fringes. For caustics described by the elementary catastrophes of singularity theory, the colors are characteristic of the type of singularity. We study the diffraction colors of the fold and cusp catastrophes. The colors can be simulated computationally as the superposition of monochromatic patterns for different wavelengths. Far from the caustic, where the luminosity contrast is negligible, the fringe colors persist; an asymptotic theory explains why. Experiments with caustics produced by refraction through irregular bathroom-window glass show good agreement with theory. Colored fringes near the cusp reveal fine lines that are not present in any of the monochromatic components; these lines are explained in terms of partial decoherence between rays with widely differing path differences. Images Fig. 1 Fig. 2 Fig. 3 Fig. 6 Fig. 8 Fig. 9 Fig. 10 PMID:11607642

  15. Diffraction before destruction

    PubMed Central

    Chapman, Henry N.; Caleman, Carl; Timneanu, Nicusor

    2014-01-01

    X-ray free-electron lasers have opened up the possibility of structure determination of protein crystals at room temperature, free of radiation damage. The femtosecond-duration pulses of these sources enable diffraction signals to be collected from samples at doses of 1000 MGy or higher. The sample is vaporized by the intense pulse, but not before the scattering that gives rise to the diffraction pattern takes place. Consequently, only a single flash diffraction pattern can be recorded from a crystal, giving rise to the method of serial crystallography where tens of thousands of patterns are collected from individual crystals that flow across the beam and the patterns are indexed and aggregated into a set of structure factors. The high-dose tolerance and the many-crystal averaging approach allow data to be collected from much smaller crystals than have been examined at synchrotron radiation facilities, even from radiation-sensitive samples. Here, we review the interaction of intense femtosecond X-ray pulses with materials and discuss the implications for structure determination. We identify various dose regimes and conclude that the strongest achievable signals for a given sample are attained at the highest possible dose rates, from highest possible pulse intensities. PMID:24914146

  16. Polychromatic diffraction contrast tomography

    SciTech Connect

    King, A.; Reischig, P.; Adrien, J.; Peetermans, S.; Ludwig, W.

    2014-11-15

    This tutorial review introduces the use of polychromatic radiation for 3D grain mapping using X-ray diffraction contrast tomography. The objective is to produce a 3D map of the grain shapes and orientations within a bulk, millimeter-sized polycrystalline sample. The use of polychromatic radiation enables the standard synchrotron X-ray technique to be applied in a wider range of contexts: 1) Using laboratory X-ray sources allows a much wider application of the diffraction contrast tomography technique. 2) Neutron sources allow large samples, or samples containing high Z elements to be studied. 3) Applied to synchrotron sources, smaller samples may be treated, or faster measurements may be possible. Challenges and particularities in the data acquisition and processing, and the limitations of the different variants, are discussed. - Highlights: • We present a tutorial review of polychromatic diffraction contrast tomography techniques. • The use of polychromatic radiation allows the standard synchrotron DCT technique to be extended to a range of other sources. • The characteristics and limitations of all variants of the techniques are derived, discussed and compared. • Examples using laboratory X-ray and cold neutron radiation are presented. • Suggestions for the future development of these techniques are presented.

  17. Neighborhood Poverty Impacts Children's Physical Health and Well-Being over Time: Evidence from the Early Development Instrument

    ERIC Educational Resources Information Center

    Cushon, Jennifer A.; Vu, Lan T. H.; Janzen, Bonnie L.; Muhajarine, Nazeem

    2011-01-01

    Research Findings: The purpose of this study was to investigate how neighborhoods and neighborhood socioeconomic disadvantage impact school readiness over time. School readiness was measured using the Early Development Instrument (EDI) for 3 populations of kindergartners in 2001, 2003, and 2005 in Saskatoon, Saskatchewan, Canada. EDI results…

  18. History of ``NANO''-Scale VERY EARLY Solid-State (and Liquid-State) Physics/Chemistry/Metallurgy/ Ceramics; Interstitial-Alloys Carbides/Nitrides/Borides/...Powders and Cermets, Rock Shocks, ...

    NASA Astrophysics Data System (ADS)

    Maiden, Colin; Siegel, Edward

    History of ``NANO'': Siegel-Matsubara-Vest-Gregson[Mtls. Sci. and Eng. 8, 6, 323(`71); Physica Status Solidi (a)11,45(`72)] VERY EARLY carbides/nitrides/borides powders/cermets solid-state physics/chemistry/metallurgy/ ceramics FIRST-EVER EXPERIMENTAL NANO-physics/chemistry[1968 ->Physica Status Solidi (a)11,45(`72); and EARLY NANO-``physics''/NANO-``chemistry'' THEORY(after: Kubo(`62)-Matsubara(`60s-`70s)-Fulde (`65) [ref.: Sugano[Microcluster-Physics, Springer('82 `98)

  19. The impact of physical maltreatment history on the adolescent mother-infant relationship: mediating and moderating effects during the transition to early parenthood.

    PubMed

    Milan, Stephanie; Lewis, Jessica; Ethier, Kathleen; Kershaw, Trace; Ickovics, Jeannette R

    2004-06-01

    Using attachment theory as a framework, this paper examines how pregnant adolescents' experiences of physical maltreatment during childhood influence the subsequent mother-infant relationship in 203 low-income adolescents followed from the 3rd trimester of pregnancy through the 1st year of parenthood. The relation between physical maltreatment history and early difficulty in the mother-infant relationship was mediated by adolescents' evaluations of the relationship with their primary caretaker and the feelings they associated with motherhood measured prior to childbirth. In addition, a supportive romantic relationship during pregnancy acted as a protective factor by moderating the impact of maltreatment history on the quality of the subsequent mother-infant relationship. Findings support the importance of assessments and interventions that consider the social context and relational history of pregnant and parenting adolescents. PMID:15228174

  20. DoE Early Career Research Program: Final Report: Model-Independent Dark-Matter Searches at the ATLAS Experiment and Applications of Many-core Computing to High Energy Physics

    SciTech Connect

    Farbin, Amir

    2015-07-15

    This is the final report of for DoE Early Career Research Program Grant Titled "Model-Independent Dark-Matter Searches at the ATLAS Experiment and Applications of Many-core Computing to High Energy Physics".

  1. Naturally Occurring Changes in Time Spent Watching Television Are Inversely Related to Frequency of Physical Activity during Early Adolescence

    ERIC Educational Resources Information Center

    Motl, Robert W.; McAuley, Edward; Birnbaum, Amanda S.; Lytle, Leslie A.

    2006-01-01

    In this longitudinal study, we examined the relationship between changes in time spent watching television and playing video games with frequency of leisure-time physical activity across a 2-year period among adolescent boys and girls (N=4594). Latent growth modelling indicated that a decrease in time spent watching television was associated with…

  2. Associations of Maternal Prenatal Smoking with Early Childhood Physical Aggression, Hyperactivity-Impulsivity, and Their Co-Occurrence

    ERIC Educational Resources Information Center

    Huijbregts, Stephan C. J.; Seguin, Jean R.; Zoccolillo, Mark; Boivin, Michel; Tremblay, Richard E.

    2007-01-01

    This study investigated associations between maternal prenatal smoking and physical aggression (PA), hyperactivity-impulsivity (HI) and co-occurring PA and HI between ages 17 and 42 months in a population sample of children born in Quebec (Canada) in 1997/1998 (N=1745). Trajectory model estimation showed three distinct developmental patterns for…

  3. Maternal versus Paternal Physical and Emotional Abuse, Affect Regulation and Risk for Depression from Adolescence to Early Adulthood

    ERIC Educational Resources Information Center

    Moretti, Marlene M.; Craig, Stephanie G.

    2013-01-01

    Objective: Current research has established that depression is a common outcome of child abuse. The current study extends previous research by examining the relationship between parental emotional and physical abuse and adolescents' depressive symptoms using a prospective longitudinal design. We anticipated that this relationship would be mediated…

  4. Teacher-Child Relationship, Parenting, and Growth in Likelihood and Severity of Physical Aggression in the Early School Years

    ERIC Educational Resources Information Center

    Runions, Kevin C.; Vitaro, Fank; Cross, Donna; Shaw, Thérèse; Hall, Margaret

    2014-01-01

    This investigation used two-part growth modeling and cross-lagged panel analysis to examine the predictive function of parenting and teacher-child relationship on the likelihood of children showing problems with parent-rated physical aggression, and on the severity of problems, for 374 children followed from prekindergarten and first grade.…

  5. The Children's Learning Center: A Study of a Self-Manipulative Physical Environment on Early Childhood Learning.

    ERIC Educational Resources Information Center

    Studio of Environmental Technology, Providence, RI.

    The Children's Learning Center in Providence, Rhode Island, is a prototypical teaching/learning environment for preschool children aged 3-5. The center represents the first prototypical application of the Multi-Activity Zones for Education (MAZE) system. This study attempts to demonstrate and test the physical and operational performances of the…

  6. Attention Problems Mediate the Association between Severity of Physical Abuse and Aggressive Behavior in a Sample of Maltreated Early Adolescents

    ERIC Educational Resources Information Center

    Garrido, Edward F.; Taussig, Heather N.; Culhane, Sara E.; Raviv, Tali

    2011-01-01

    Empirical evidence has accumulated documenting an association between childhood physical abuse and aggressive behavior. Relatively fewer studies have explored possible mediating mechanisms that may explain this association. The purpose of the current study was to examine whether caregiver- and youth-reported attention problems mediate the…

  7. Socialization of Physical and Social Aggression in Early Adolescents' Peer Groups: High-Status Peers, Individual Status, and Gender

    ERIC Educational Resources Information Center

    Shi, Bing; Xie, Hongling

    2012-01-01

    The influence of high-status peers on a target individual's physical and manipulative social aggression in peer groups was examined in a diverse sample of seventh-grade students. A total of 245 individual members belonging to 65 groups were included in analyses. Aggression was assessed by peer and victim nominations in the fall and spring…

  8. The Quantitative and Qualitative Analysis of Cohorts' Early Enrollment in Physics: concurrent with enrollment in mathematics, biology and chemistry

    NASA Astrophysics Data System (ADS)

    Lynch, Robert Bruce Rodes

    Cohorts of 48 entering biological science majors was recruited in the fall of 2007 and again in 2008 and 2009 for the Interdisciplinary Science Experience (ISE). These ISE students enrolled in their own sections of standard courses of physics, chemistry, and biology. In these courses average ISE student out-performed their non-cohort peers by up to a full letter grade. A qualitative analysis of ISE student interviews illuminates the student experience and shows how the ISE students perceived themselves to be different than their non-cohort peers. Quantitative modeling of student performance shows that higher grades are correlated with multiple factors. These factors includes admissions characteristics such as high school GPA, and SAT scores, as well as demographic information. These trends support and elaborate on the selection narratives told by participants. Additionally the quantitative model found that higher student performance is predicted by structural aspects of the ISE program, specifically the timing of course, enrolling as a freshmen in many of their courses, and the sequencing of physics and chemistry courses. There is a statistically significant benefit to student performance in general and organic chemistry courses associated with completing the first quarter of the Physics for Bio-Science majors prior to enrollment. Further the combination of quantitative and qualitative data suggest that there is a epistemological transfer of problem solving skills and outlook from the physics to the chemistry courses.

  9. Early Outcome of Posterior Cervical Endoscopic Discectomy: An Alternative Treatment Choice for Physically/Socially Active Patients

    PubMed Central

    Kim, Chi Heon; Kim, Hyun Jib; Jahng, Tae Ahn; Kim, Dong Gyu

    2009-01-01

    Anterior cervical discectomy and fusion (ACDF) is currently the standard treatment for cervical disc disease. Some patients wish to be treated with a less invasive method, because of their social/physical situations. Here we present one method of treatments for socially/physically active patients. Three patients had triceps weakness and mild posterior neck pain. The offending lesions were at the C6-7 level. All were middle-aged soldiers with families. If conventional ACDF were performed, they would have to retire from the military according to the regulation. They had to be able to perform military drills after the treatment if they were going to be able to keep their jobs. Because of their social/physical situations, all wanted to choose method with that they could treat the disease and keep their jobs. For these reasons, the posterior cervical endoscopic discectomies were performed. Ruptured fragments were successfully removed in all. The arm pain improved by more than 90% in two patients by 7 days and in the other patient by 2 months, respectively (excellent outcome by Macnab's criteria). None of the operations caused instability. All of the patients are currently able to successfully perform their military drills without difficulty. The posterior cervical endoscopic discectomy may be a promising alternative for the physically/socially active patients. PMID:19399274

  10. Associations of fatigue from mid to late life with physical performance and strength in early old age: Results from a British prospective cohort study

    PubMed Central

    Mänty, Minna; Kuh, Diana; Cooper, Rachel

    2015-01-01

    OBJECTIVE To examine associations of fatigue in mid and later life with physical performance and strength in early old age. METHODS Data on approximately 1800 men and women from the UK Medical Research Council National Survey of Health and Development with data on fatigue at ages 43 and 60-64 years were used. Fatigue was defined as perceived tiredness and was assessed prospectively at ages 43 and 60-64. At both ages, participants were categorized as having no, occasional or frequent fatigue. Physical performance and strength were measured at age 60-64 using four objective measures: grip strength, standing balance, chair rising, and timed get-up-and-go (TUG) tests. RESULTS There were associations between reports of frequent fatigue at both ages and poorer grip strength, chair rise and TUG performance at 60-64 years. Furthermore, individuals reporting frequent fatigue at both ages had weaker grip strength (β -4.09 kg, 95% CI -6.71, -1.48), and slower chair rise (β -4.65 rep./min, 95% CI -6.65, -2.64) and TUG (β -4.22 cm/s, 95% CI -12.16, -2.28) speeds when compared to those who reported no fatigue at both time points. These associations were robust and were maintained after adjustment for a range of covariates including physical activity and health status. CONCLUSIONS Reports of frequent fatigue were associated with poorer physical performance in early old age, especially if sustained from mid to later life. These findings indicate that it is not just fatigue but fatigue sustained across adulthood that has implications for later life functioning. PMID:26176776

  11. Diffraction of a Laser Beam.

    ERIC Educational Resources Information Center

    Jodoin, Ronald E.

    1979-01-01

    Investigates the effect of the nonuniform irradiance across a laser beam on diffraction of the beam, specifically the Fraunhofer diffraction of a laser beam with a Gaussian irradiance profile as it passes through a circular aperture. (GA)

  12. Aberrations of diffracted wave fields. II. Diffraction gratings.

    PubMed

    Mahajan, V N

    2000-12-01

    The Rayleigh-Sommerfeld theory is applied to diffraction of a spherical wave by a grating. The grating equation is obtained from the aberration-free diffraction pattern, and its aberrations are shown to be the same as the conventional aberrations obtained by using Fermat's principle. These aberrations are shown to be not associated with the diffraction process. Moreover, it is shown that the irradiance distribution of a certain diffraction order is the Fraunhofer diffraction pattern of the grating aperture as a whole aberrated by the aberration of that order. PMID:11140481

  13. Recent diffractive results from HERA

    NASA Astrophysics Data System (ADS)

    Valkárová, Alice

    2016-07-01

    The diffractive dijet cross sections for photoproduction and deep inelastic scattering were studied and compared with theoretical NLO QCD predictions. The results of exclusive dijet production were compared to predictions from models which are based on different assumptions about the nature of diffractive exchange. Isolated prompt photons in diffractive photoproduction produced inclusively or together with a jet were studied for the first time.

  14. Spectral diffraction efficiency characterization of broadband diffractive optical elements.

    SciTech Connect

    Choi, Junoh; Cruz-Cabrera, Alvaro Augusto; Tanbakuchi, Anthony

    2013-03-01

    Diffractive optical elements, with their thin profile and unique dispersion properties, have been studied and utilized in a number of optical systems, often yielding smaller and lighter systems. Despite the interest in and study of diffractive elements, the application has been limited to narrow spectral bands. This is due to the etch depths, which are optimized for optical path differences of only a single wavelength, consequently leading to rapid decline in efficiency as the working wavelength shifts away from the design wavelength. Various broadband diffractive design methodologies have recently been developed that improve spectral diffraction efficiency and expand the working bandwidth of diffractive elements. We have developed diffraction efficiency models and utilized the models to design, fabricate, and test two such extended bandwidth diffractive designs.

  15. The effects of plasma physics target shrapnel and debris plumes arising from early operations of the Orion laser

    NASA Astrophysics Data System (ADS)

    Andrew, J.; Egan, D.; Miller, S.; Pearce, A.; Penman, R.; Scott, D.

    2014-10-01

    When lasers are used to produce high temperature, high density plasmas from solid targets it is inevitable that the targets are turned into a variety of products [gas, liquid, solid, sub-atomic particles and electromagnetic radiation] that are distributed around the surfaces of the vacuum chamber used to field such experiments. These by products are produced in plumes of debris and shrapnel that depend on the irradiation conditions, target materials and target geometry. We have monitored the distribution of such plumes by witness plates and used microscopy, photography and spectrophotometry to determine the physical state of material in the plumes and the spatial distribution from various target geometries. The impact of this material on the operations of laser optics and plasma physics diagnostics is discussed.

  16. A survey of interstellar neutral potassium. I - Abundances and physical conditions in clouds toward 188 early-type stars

    NASA Technical Reports Server (NTRS)

    Chaffee, F. H., Jr.; White, R. E.

    1982-01-01

    Observations of interstellar absorption in the resonance doublet 7664, 7698 A of neutral potassium toward 188 early-type stars at a spectral resolution of 8 km/s are reported. The 7664 A line is successfully separated from nearly coincident telluric O2 absorption for all but a few of the 165 stars for which K I absorption is detected, making possible an abundance analysis by the doublet ratio method. The relationships between the potassium abundances and other atomic abundances, the abundance of molecular hydrogen, and interstellar reddening are investigated.

  17. INELASTIC DIFFRACTION AT HEAVY ION COLLIDERS.

    SciTech Connect

    WHITE, S.

    2005-01-01

    The heavy ion physics approach to global event characterization has led us to instrument the forward region in the PHENIX experiment at RHIC. In heavy ion collisions this coverage yields a measurement of the ''spectator'' energy and its distribution about the beam direction. This energy flow is the basis of event-by-event determination of the centrality and reaction plane which are key to analyzing particle production in heavy ion collisions. These same tools have also enabled a unique set of measurements on inelastic diffraction with proton, deuteron and gold ion beams in the PHENIX experiment. We present first new results on this topic and discuss briefly the opportunity for diffractive physics with Heavy Ion beams at the LHC.

  18. Multiple early victimization experiences as a pathway to explain physical health disparities among sexual minority and heterosexual individuals.

    PubMed

    Andersen, Judith P; Zou, Christopher; Blosnich, John

    2015-05-01

    Prior research shows that health disparities exist between sexual minority and heterosexual individuals. We extend the literature by testing if the higher prevalence of childhood victimization experienced by sexual minority individuals accounts for lifetime health disparities. Heterosexual (n = 422) and sexual minority (n = 681) participants were recruited on-line in North America. Respondents completed surveys about their childhood victimization experiences (i.e., maltreatment by adults and peer victimization) and lifetime physician-diagnosed physical health conditions. Results showed that sexual minority individuals experienced higher prevalence of childhood victimization and lifetime physical health problems than heterosexuals. Mediation analyses indicated that maltreatment by adults and peer bullying explained the health disparities between sexual minority individuals and heterosexuals. This study is the first to show that multiple childhood victimization experiences may be one pathway to explain lifetime physical health disparities. Intervention programs reducing the perpetration of violence against sexual minority individuals are critical to reduce health care needs related to victimization experiences. PMID:25864147

  19. Effect of early programmes of high and low intensity exercise on physical performance after transmural acute myocardial infarction.

    PubMed Central

    Goble, A J; Hare, D L; Macdonald, P S; Oliver, R G; Reid, M A; Worcester, M C

    1991-01-01

    Does a programme of light exercise training after acute myocardial infarction produce the same improvement in treadmill performance as aerobic exercise training? Three hundred and eight men from a consecutive series of 479 men with transmural (Q wave) acute myocardial infarction, admitted to a single coronary care unit, were randomly allocated to eight weeks of group aerobic exercise training or group light exercise. Groups were well matched for all characteristics other than site of infarction, which did not significantly affect results. Mean (SD) physical working capacity (metabolic equivalents) determined by treadmill testing at the start of the study (in the third week after infarction) was 6.8 (2.2) v 6.7 (2.5) METs, at the end (in the eleventh week after infarction) 10.8 (2.3) v 9.9 (2.4) METs, and at 12 month review 10.8 (2.4) v 10.7 (1.9) METs for the exercise training group and the light exercise group respectively. The difference of 0.9 METs at the end of the study was the only significant difference between groups. There were no significant intergroup differences at any stage in resting and maximal heart rate, resting and maximal systolic blood pressure, or rate-pressure product. Apart from a small temporarily greater physical working capacity, the physical benefits of aerobic exercise training were equally well achieved by group light exercise. PMID:2015119

  20. Hard diffraction in Pythia 8

    NASA Astrophysics Data System (ADS)

    Overgaard Rasmussen, Christine

    2016-07-01

    We present an overview of the options for diffraction implemented in the general-purpose event generator Pythia 8 [1]. We review the existing model for soft diffraction and present a new model for hard diffraction. Both models use the Pomeron approach pioneered by Ingelman and Schlein, factorising the diffractive cross section into a Pomeron flux and a Pomeron PDF, with several choices for both implemented in Pythia 8. The model of hard diffraction is implemented as a part of the multiparton interactions (MPI) framework, thus introducing a dynamical gap survival probability that explicitly breaks factorisation.

  1. Physics Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1982

    1982-01-01

    Demonstrations, procedures, games, teaching suggestions and information on a variety of physics topics are presented, including hydraulic rams, units and formulae, static electric motors, a computer graphics program, diffraction, adaptation of a basic meter, photoelasticity, photo-diodes, radioactive decay, and analog-digital conversions. (DC)

  2. Persistence or Change in Leisure-Time Physical Activity Habits and Waist Gain During Early Adulthood: A Twin-Study

    PubMed Central

    Rottensteiner, Mirva; Pietiläinen, Kirsi H.; Kaprio, Jaakko; Kujala, Urho M.

    2014-01-01

    Objective To determine the relationship between persistence or change in leisure-time physical activity habits and waist gain among young adults. Design and Methods Population-based cohort study among 3383 Finnish twin individuals (1578 men) from five birth cohorts (1975–1979), who answered questionnaires at mean ages of 24.4 y (SD 0.9) and 33.9 y (SD 1.2), with reported self-measured waist circumference. Persistence or change in leisure-time physical activity habits was defined based on thirds of activity metabolic equivalent h/day during follow-up (mean 9.5 y; SD 0.7). Results Decreased activity was linked to greater waist gain compared to increased activity (3.6 cm, P<0.001 for men; 3.1 cm, P<0.001 for women). Among same-sex activity discordant twin pairs, twins who decreased activity gained an average 2.8 cm (95%CI 0.4 to 5.1, P=0.009) more waist than their co-twins who increased activity (n=85 pairs); among MZ twin pairs (n=43), the difference was 4.2 cm (95%CI 1.2 to 7.2, P=0.008). Conclusions Among young adults, an increase in leisure-time physical activity or staying active during a decade of follow-up was associated with less waist gain, but any decrease in activity level, regardless baseline activity, led to waist gain that was similar to that associated with being persistently inactive. PMID:24839266

  3. Structured beam diffraction.

    PubMed

    Castagna, R; Di Donato, A; Nucara, L; Xu, J H; Lucchetta, D E; Simoni, F

    2016-04-01

    We report on the observation of a modulated pattern induced by a single laser beam in a polymeric film. In spite of the simple geometrical configuration, the analysis of the far field diffraction pattern allows a sensitive retrieving of the wavelength of the recording beam and of its incidence angle, pointing out the high information content of the recorded spot. A theoretical model is presented which satisfactorily explains the observed behavior. It takes into account the interaction of structured light with structured matter with the same symmetries and spatial modulation frequencies close to each other. This result shows a feature of the interaction between structured light and structured matter which has not been explored yet. PMID:27192262

  4. Phase shifting diffraction interferometer

    DOEpatents

    Sommargren, Gary E.

    1996-01-01

    An interferometer which has the capability of measuring optical elements and systems with an accuracy of .lambda./1000 where .lambda. is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about .lambda./50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms.

  5. Phase shifting diffraction interferometer

    DOEpatents

    Sommargren, G.E.

    1996-08-29

    An interferometer which has the capability of measuring optical elements and systems with an accuracy of {lambda}/1000 where {lambda} is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about {lambda}/50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms. 8 figs.

  6. Multilayer diffraction grating

    DOEpatents

    Barbee, Jr., Troy W.

    1990-01-01

    This invention is for a reflection diffraction grating that functions at X-ray to VUV wavelengths and at normal angles of incidence. The novel grating is comprised of a laminar grating of period D with flat-topped grating bars. A multiplicity of layered synthetic microstructures, of period d and comprised of alternating flat layers of two different materials, are disposed on the tops of the grating bars of the laminar grating. In another embodiment of the grating, a second multiplicity of layered synthetic microstructures are also disposed on the flat faces, of the base of the grating, between the bars. D is in the approximate range from 3,000 to 50,000 Angstroms, but d is in the approximate range from 10 to 400 Angstroms. The laminar grating and the layered microstructures cooperatively interact to provide many novel and beneficial instrumentational advantages.

  7. Multilayer diffraction grating

    DOEpatents

    Barbee, T.W. Jr.

    1990-04-10

    This invention is for a reflection diffraction grating that functions at X-ray to VUV wavelengths and at normal angles of incidence. The novel grating is comprised of a laminar grating of period D with flat-topped grating bars. A multiplicity of layered synthetic microstructures, of period d and comprised of alternating flat layers of two different materials, are disposed on the tops of the grating bars of the laminar grating. In another embodiment of the grating, a second multiplicity of layered synthetic microstructures are also disposed on the flat faces, of the base of the grating, between the bars. D is in the approximate range from 3,000 to 50,000 Angstroms, but d is in the approximate range from 10 to 400 Angstroms. The laminar grating and the layered microstructures cooperatively interact to provide many novel and beneficial instrumentational advantages. 2 figs.

  8. N.G. Basov and early works on semiconductor lasers at P.N. Lebedev Physics Institute

    SciTech Connect

    Eliseev, P G

    2012-12-31

    A survey is presented of works on creation and investigation of semiconductor lasers during 1957 - 1977 at the P.N. Lebedev Physics Institute. Many of these works were initiated by N.G. Basov, starting from pre-laser time, when N.G. Basov and his coworkers formulated principal conditions of creation of lasers on interband transitions in semiconductors. Main directions of further works were diode lasers based on various materials and structures, their characteristics of output power, high-speed operation and reliability. (special issue devoted to the 90th anniversary of n.g. basov)

  9. Science and miscegenation in the early twentieth century: Edgard Roquette-Pinto's debates and controversies with US physical anthropology.

    PubMed

    Souza, Vanderlei Sebastião de

    2016-01-01

    The article analyzes Brazilian anthropologist Edgard Roquette-Pinto's participation in the international debate that involved the field of physical anthropology and discussions on miscegenation in the first decades of the twentieth century. Special focus is on his readings and interpretations of a group of US anthropologists and eugenicists and his controversies with them, including Charles Davenport, Madison Grant, and Franz Boas. The article explores the various ways in which Roquette-Pinto interpreted and incorporated their ideas and how his anthropological interpretations took on new meanings when they moved beyond Brazil's borders. PMID:27438731

  10. Patterns of Leisure-Time Physical Activity Participation in a British Birth Cohort at Early Old Age

    PubMed Central

    Martin, Kathryn R.; Cooper, Rachel; Harris, Tamara B.; Brage, Soren; Hardy, Rebecca; Kuh, Diana

    2014-01-01

    Using data from a nationally representative British birth cohort we characterized the type and diversity of leisure-time physical activity that 2,188 participants (age 60–64 years) engaged in throughout the year by gender and obesity. Participants most commonly reported walking (71%), swimming (33%), floor exercises (24%) and cycling (15%). Sixty-two percent of participants reported ≥2 activities in the past year and 40% reported diversity on a regular basis. Regular engagement in different types of activity (cardio-respiratory, balance/flexibility and strength) was reported by 67%, 19% and 11% of participants, respectively. We found gender differences, as well as differences by obesity status, in the activities reported, the levels of activity diversity and activity type. Non-obese participants had greater activity diversity, and more often reported activities beneficial for cardio-respiratory health and balance/flexibility than obese participants. These findings may be used to inform the development of trials of physical activity interventions targeting older adults, and those older adults with high body mass index. PMID:24911018

  11. Age-Related Decrements in Heat Dissipation during Physical Activity Occur as Early as the Age of 40

    PubMed Central

    Larose, Joanie; Boulay, Pierre; Sigal, Ronald J.; Wright, Heather E.; Kenny, Glen P.

    2013-01-01

    Older adults typically experience greater levels of thermal strain during physical efforts in the heat compared to young individuals. While this may be related to an age-dependent reduction in whole-body sweating, no study has clearly delineated at what age this occurs. In the present study, we report direct measurements of human heat dissipation during physical activity in the heat in males ranging in age from 20–70 years. Eighty-five males performed four 15-min bouts of cycling separated by 15-min rest periods, in a calorimeter regulated to 35°C and 20% relative humidity. Direct calorimetry was used to measure total heat loss (whole-body evaporative heat loss and dry heat exchange). We also used indirect calorimetry as a continuous measure of metabolic heat production. Body heat storage was calculated as the temporal summation of heat production and total heat loss over the experimental session. Whole-body sweat rate (WBSR) was calculated from measurements of evaporative heat loss. Males were divided into five age categories for the analysis of WBSR and body heat storage: 20–31 years (n = 18), 40–44 years (n = 15), 45–49 years (n = 15), 50–55 years (n = 21) and 56–70 years (n = 16). Relative to young males, WBSR was reduced in males aged 56–70 during each exercise (all P<0.05), in males aged 50–55 during the second (P = 0.031) and third exercises (P = 0.028) and in males aged 45–49 during the final exercise bout (P = 0.046). Although not significantly different, 40–44 years old males also had a lower rate of heat loss compared to younger males. Over the sum of two hours, the change in body heat content was greater in males 40–70 years compared to young males (all P<0.05). Our findings suggest that middle-aged and older adults have impairments in heat dissipation when doing physical activity in the heat, thus possibly increasing their risk of heat-related illness under such conditions. PMID:24349447

  12. Evaluation design of New York City's regulations on nutrition, physical activity, and screen time in early child care centers.

    PubMed

    Breck, Andrew; Goodman, Ken; Dunn, Lillian; Stephens, Robert L; Dawkins, Nicola; Dixon, Beth; Jernigan, Jan; Kakietek, Jakub; Lesesne, Catherine; Lessard, Laura; Nonas, Cathy; O'Dell, Sarah Abood; Osuji, Thearis A; Bronson, Bernice; Xu, Ye; Kettel Khan, Laura

    2014-01-01

    This article describes the multi-method cross-sectional design used to evaluate New York City Department of Health and Mental Hygiene's regulations of nutrition, physical activity, and screen time for children aged 3 years or older in licensed group child care centers. The Center Evaluation Component collected data from a stratified random sample of 176 licensed group child care centers in New York City. Compliance with the regulations was measured through a review of center records, a facility inventory, and interviews of center directors, lead teachers, and food service staff. The Classroom Evaluation Component included an observational and biometric study of a sample of approximately 1,400 children aged 3 or 4 years attending 110 child care centers and was designed to complement the center component at the classroom and child level. The study methodology detailed in this paper may aid researchers in designing policy evaluation studies that can inform other jurisdictions considering similar policies. PMID:25321635

  13. Studies of early-type variable stars. III - The orbit and physical dimensions for V 380 Cygni

    NASA Astrophysics Data System (ADS)

    Hill, G.; Batten, A. H.

    1984-12-01

    The spectroscopic orbits for the primary and secondary components of V 380 Cygni have been redetermined by cross-correlation techniques. New masses and orbital elements differ only slightly from those published previously by Batten (1962). However, the spectroscopic data allow the presence of apsidal motion contrary, to previous interpretations. Relative radii, temperatures and orbital inclination have resulted from a solution of three independent light curves. When combined with the spectroscopic data they yield physical dimensions for the component stars, a chemical composition of (X, Y), (0.66, 0.30) and a system age of about 8 million yr. In about 500,000 yr the primary will reach the inner Lagrangian surface and the system will begin the mass-transfer phase of its evolution. Theoretical and observational apsidal periods near 1500 yr are in good accord.

  14. Readiness of the ATLAS Spanish Federated Tier-2 for the Physics Analysis of the early collision events at the LHC

    NASA Astrophysics Data System (ADS)

    Oliver, E.; Nadal, J.; Pardo, J.; Amorós, G.; Borrego, C.; Campos, M.; Del Cano, L.; Del Peso, J.; Espinal, X.; Fassi, F.; Fernández, A.; Fernández, P.; González, S.; Kaci, M.; Lamas, A.; March, L.; Muñoz, L.; Pacheco, A.; Salt, J.; Sánchez, J.; Villaplana, M.; Vives, R.

    2010-04-01

    In this contribution an evaluation of the readiness parameters for the Spanish ATLAS Federated Tier-2 is presented, regarding the ATLAS data taking which is expected to start by the end of the year 2009. Special attention will be paid to the Physics Analysis from different points of view: Data Management, Simulated events Production and Distributed Analysis Tests. Several use cases of Distributed Analysis in GRID infrastructures and local interactive analysis in non-Grid farms, are provided, in order to evaluate the interoperability between both environments, and to compare the different performances. The prototypes for local computing infrastructures for data analysis are described. Moreover, information about a local analysis facilities, called Tier-3, is given.

  15. Interference and Diffraction.

    ERIC Educational Resources Information Center

    Ross, Marc H.

    This monograph was written for the Conference on the New Instructional Materials in Physics, held at the University of Washington in summer, 1965. The measurement of very small distances and sizes, and the concept of models are discussed in the introduction. The optics of slits is dealt with in chapter 2. Chapter 3 presents the optics of holes.…

  16. On learning to draw the distinction between physical and metaphorical motion: is metaphor an early emerging cognitive and linguistic capacity?

    PubMed

    Ozçalişkan, Seyda

    2005-05-01

    Situated within the framework of the conceptual metaphor theory (Lakoff & Johnson, 1999), this study investigated young children's understanding of metaphorical extensions of spatial motion. Metaphor was defined as a conceptual-linguistic mapping between a source and a target domain. The study focused on metaphors that are structured by the source domain of motion in space (e.g. time flies by, ideas pass through one's mind, sickness crawls through one's body). The study investigated whether metaphor comprehension varied by the age of the participant, target domain of the metaphorical mapping, and the conventionality of the linguistic form with which the metaphor was conveyed. Data were gathered using a story comprehension task and a semi-structured interview from 60 monolingual Turkish-speaking children, at the mean ages 3;6, 4;5 and 5;5 (20 participants per age group), and 20 adult native speakers of Turkish. The results showed metaphor understanding to be an early emerging cognitive and linguistic capacity. PMID:16045252

  17. Detonation diffraction in gases

    SciTech Connect

    Pintgen, F.; Shepherd, J.E.

    2009-03-15

    We have experimentally investigated detonation diffraction out of a round tube into an unconfined half-space. The focus of our study is examining how the extent of detonation cellular instability influences the quantitative and qualitative features of diffraction. Detailed quantitative and qualitative measurements were obtained through simultaneous schlieren imaging, multiple-exposure chemiluminescence imaging, and planar laser-induced fluorescence imaging of OH molecules. Two types of stoichiometric mixtures, highly diluted H{sub 2}-O{sub 2}-Ar and H{sub 2}-N{sub 2}O, were studied in the sub-critical, critical and super-critical regime. These mixture types represent extreme cases in the classification of cellular instability with highly diluted H{sub 2}-O{sub 2}-Ar mixtures having very regular instability structures and H{sub 2}-N{sub 2}O having very irregular instability structures. The most striking differences between the mixtures occur in the sub-critical and critical regimes, for which the detonation fails to transition into the unconfined half-space. For the H{sub 2}-O{sub 2}-Ar mixture, the velocity on the center line was found to decay significantly slower than for the H{sub 2}-N{sub 2}O mixture. In case of the H{sub 2}-O{sub 2}-Ar mixture, it was evident from simultaneous schlieren-fluorescence images that the reaction front was coupled to the lead shock front up to 2.3 tube diameters from the exit plane. For the H{sub 2}-N{sub 2}O mixture, the reaction front velocity decreased to 60% of the corresponding Chapman-Jouguet value at 1.1 tube diameters from the tube exit plane. A geometric acoustic model showed that the observed differences in failure patterns are not caused by the differences in thermodynamic properties of the two mixtures but is linked to the larger effective activation energy and critical decay time in the H{sub 2}-N{sub 2}O mixture as compared to the H{sub 2}-O{sub 2}-Ar mixture. The re-initiation events appear similar for the two

  18. Diffraction contrast imaging using virtual apertures.

    PubMed

    Gammer, Christoph; Burak Ozdol, V; Liebscher, Christian H; Minor, Andrew M

    2015-08-01

    Two methods on how to obtain the full diffraction information from a sample region and the associated reconstruction of images or diffraction patterns using virtual apertures are demonstrated. In a STEM-based approach, diffraction patterns are recorded for each beam position using a small probe convergence angle. Similarly, a tilt series of TEM dark-field images is acquired. The resulting datasets allow the reconstruction of either electron diffraction patterns, or bright-, dark- or annular dark-field images using virtual apertures. The experimental procedures of both methods are presented in the paper and are applied to a precipitation strengthened and creep deformed ferritic alloy with a complex microstructure. The reconstructed virtual images are compared with conventional TEM images. The major advantage is that arbitrarily shaped virtual apertures generated with image processing software can be designed without facing any physical limitations. In addition, any virtual detector that is specifically designed according to the underlying crystal structure can be created to optimize image contrast. PMID:25840371

  19. X-Ray Diffraction on NIF

    SciTech Connect

    Eggert, J H; Wark, J

    2012-02-15

    The National Ignition Facility (NIF) is currently a 192 beam, 1.6 MJ laser. NIF Ramp-Compression Experiments have already made the relevant exo-planet pressure range from 1 to 50 Mbar accessible. We Proposed to Study Carbon Phases by X-Ray Diffraction on NIF. Just a few years ago, ultra-high pressure phase diagrams for materials were very 'simple'. New experiments and theories point out surprising and decidedly complex behavior at the highest pressures considered. High pressures phases of aluminum are also predicted to be complex. Recent metadynamics survey of carbon proposed a dynamic pathway among multiple phases. We need to develop diagnostics and techniques to explore this new regime of highly compressed matter science. X-Ray Diffraction - Understand the phase diagram/EOS/strength/texture of materials to 10's of Mbar. Strategy and physics goals: (1) Powder diffraction; (2) Begin with diamond; (3) Continue with metals etc.; (4) Explore phase diagrams; (5) Develop liquid diffraction; and (6) Reduce background/improve resolution.

  20. Survey of interstellar neutral potassium. I. Abundances and physical conditions in clouds toward 188 early-type stars

    SciTech Connect

    Chaffee, F.H. Jr.; White, R.E.

    1982-10-01

    This paper reports observation of interstellar absorption in the resonance doublet lambdalambda7664,7698 of neutral potassium toward 188 early-type stars at a spectral resolution of 8 km s/sup -1/. The lambda7664 line is successfully separated from nearly coincident telluric O/sub 2/ absorption for all but a few of the 165 stars for which K I absorption is detected, allowing abundance analysis by the doublet ratio method. Comparisons of the K I column densities with those of Na I, total H, and H/sub 2/, respectively, for more than 20 of the brigther survey stars and with that of C I for seven stars yield the following results: logdelta/sub K//delta/sub Na/ = -0.1, logdelta/sub K/delta/sub C/r/ (L/sub pc/) = -1.0, logdelta/sub K//delta/sub C/ = -0.2, logdelta/sub K/delta/sub C/r/(R/R/sub 0/) = 0.75, where delta/sub X/ represents the depletion factor (< or =1) for element X, L is the thickness of the absorbing region, r = n/sub e//n/sub C/ is the ratio of the density of free electrons to that of carbon, and R/R/sub 0/ is the ratio of the H/sub 2/ formation rate to the usually adopted value of 3--10/sup -17/ cm/sup 3/ s/sup -1/. These results depend on the adopted single cloud theoretical model but are otherwise well determined.

  1. The role of occupational therapists and physical therapists in elementary school system early intervening services and response to intervention: a case report.

    PubMed

    Reeder, Deborah L; Arnold, Sandra H; Jeffries, Lynn M; McEwen, Irene R

    2011-02-01

    The Individuals with Disabilities Improvement Act and No Child Left Behind Act broadened the roles of occupational therapists (OTs) and physical therapists (PTs) to include therapist participation in early intervening services including response to intervention (RTI). This case report describes one school district's inclusion of OT and PT in the elementary school RTI program by identifying and implementing role responsibility and changing workloads for therapists. Therapist responsibilities included (a) administering a screening tool, (b) educating and supporting teachers and staff, (c) providing student resources and intervention strategies, and (d) referring students from RTI to special education and related services. Teachers responded positively using therapist-provided strategies and support. Limitations included an increased workload because of large numbers of students to screen and very few staff available for screening. Future research should include longitudinal studies that measure student responses to therapy intervention, teacher responses to collaboration, and the use of intervention strategies over time. PMID:20735199

  2. Cross-national comparison of prenatal methamphetamine exposure on infant and early child physical growth: A natural experiment

    PubMed Central

    Abar, Beau; LaGasse, Linda L.; Wouldes, Trecia; Derauf, Chris; Newman, Elana; Shah, Rizwan; Smith, Lynne M.; Arria, Amelia M.; Huestis, Marilyn A.; DellaGrotta, Sheri; Dansereau, Lynne M.; Wilcox, Tara; Neal, Charles R.; Lester, Barry M.

    2013-01-01

    The current study seeks to compare the effects of prenatal methamphetamine exposure (PME) on infant and child physical growth between the United States (US) and New Zealand (NZ). This cross-national comparison provides a unique opportunity to examine the potential impact of services provided to drug using mothers on child health. Methods The longitudinal Infant Development, Environment and Lifestyle (IDEAL) study of PME from birth to 36 months was conducted in the US and NZ. The US cohort included 204 children with PME and 212 non-PME matched comparisons (NPME); the NZ cohort included 108 children with PME and 115 NPME matched comparisons. Latent growth curve models were used to examine effects of PME, country of origin, and the country × PME interaction on growth in length/height and weight. Results In regard to length/height, PME and country of origin were associated with initial length and growth over time. There was also a significant interaction effect, such that children with PME in the US were shorter at birth than children with PME in NZ after controlling for other prenatal exposures, infant set, socioeconomic status, and maternal height. In regard to weight, there was only an effect of country of origin. Conclusions Effects of PME on infant and child growth were shown to differ across countries, with exposed children in NZ faring better than exposed children in the US. Implications for prevention programs and public policy are discussed. PMID:23943149

  3. Study of optical Laue diffraction

    SciTech Connect

    Chakravarthy, Giridhar E-mail: aloksharan@email.com; Allam, Srinivasa Rao E-mail: aloksharan@email.com; Satyanarayana, S. V. M. E-mail: aloksharan@email.com; Sharan, Alok E-mail: aloksharan@email.com

    2014-10-15

    We present the study of the optical diffraction pattern of one and two-dimensional gratings with defects, designed using desktop pc and printed on OHP sheet using laser printer. Gratings so prepared, using novel low cost technique provides good visual aid in teaching. Diffraction pattern of the monochromatic light (632.8nm) from the grating so designed is similar to that of x-ray diffraction pattern of crystal lattice with point defects in one and two-dimensions. Here both optical and x-ray diffractions are Fraunhofer. The information about the crystalline lattice structure and the defect size can be known.

  4. Electrically-programmable diffraction grating

    DOEpatents

    Ricco, Antonio J.; Butler, Michael A.; Sinclair, Michael B.; Senturia, Stephen D.

    1998-01-01

    An electrically-programmable diffraction grating. The programmable grating includes a substrate having a plurality of electrodes formed thereon and a moveable grating element above each of the electrodes. The grating elements are electrostatically programmable to form a diffraction grating for diffracting an incident beam of light as it is reflected from the upper surfaces of the grating elements. The programmable diffraction grating, formed by a micromachining process, has applications for optical information processing (e.g. optical correlators and computers), for multiplexing and demultiplexing a plurality of light beams of different wavelengths (e.g. for optical fiber communications), and for forming spectrometers (e.g. correlation and scanning spectrometers).

  5. Recent CMS results on diffraction

    NASA Astrophysics Data System (ADS)

    Benoît, Roland

    2015-03-01

    Recent CMS results on diffraction are presented. These include the measurements of the soft diffractive cross sections, of the forward rapidity gap cross section, of the diffractive dijet cross section, the measurement of a large rapidity gap in W and Z boson events and the measurement of the pseudorapidity distribution of charged particles in a single diffractive enhanced sample. This last measurement is the first common result of the CMS and TOTEM collaborations. Some prospects of common CMS-TOTEM data taking are also discussed.

  6. Optical Diffraction in Close Proximity to Plane Apertures. II. Comparison of Half-Plane Diffraction Theories

    PubMed Central

    Mielenz, Klaus D.

    2003-01-01

    The accuracy and physical significance of the classical Rayleigh-Sommerfeld and Kirchhoff diffraction integrals are assessed in the context of Sommerfeld’s rigorous theory of half-plane diffraction and Maxwell’s equations. It is shown that the Rayleigh-Sommerfeld integrals are in satisfactory agreement with Sommerfeld’s theory in most of the positive near zone, except at sub-wavelength distances from the screen. On account of the bidirectional nature of diffraction by metallic screens the Rayleigh-Sommerfeld integrals themselves cannot be used for irradiance calculations, but must first be resolved into their forward and reverse components and it is found that Kirchhoff’s integral is the appropriate measure of the forward irradiance. Because of the inadequate boundary conditions assumed in their derivation the Rayleigh-Sommerfeld and Kirchhoff integrals do not correctly describe the flow of energy through the aperture.

  7. Factors associated with early childhood education and care service implementation of healthy eating and physical activity policies and practices in Australia: a cross-sectional study.

    PubMed

    Wolfenden, Luke; Finch, Meghan; Nathan, Nicole; Weaver, Natasha; Wiggers, John; Yoong, Sze Lin; Jones, Jannah; Dodds, Pennie; Wyse, Rebecca; Sutherland, Rachel; Gillham, Karen

    2015-09-01

    Many early childhood education and care (ECEC) services fail to implement recommended policies and practices supportive of healthy eating and physical activity. The purpose of this study was to assess whether certain theoretically-based factors are associated with implementation of healthy eating and physical activity policies and practices in a sample of ECEC services. A cross-sectional survey was conducted with Service Managers of ECEC services. The survey assessed the operational characteristics, policy, and practice implementation, and 13 factors were suggested by Damschroder's Consolidated Framework for Implementation Research to impede or promote implementation. Logistic regression analyses found a significant association between implementation factor score and full implementation (OR 1.38; 95% CI 1.18-1.61; p = <0.01), indicating that for every one point increase in implementation score, ECEC services were 38 % more likely to be fully implementing the policies and practices. The findings highlight the opportunities for improving implementation of obesity prevention interventions in this setting by developing interventions that address such factors. PMID:26327938

  8. Treatment of Mental or Physical Health Problems in a Combat Zone: Comparisons of Postdeployment Mental Health and Early Separation From Service.

    PubMed

    Conway, Terry L; Schmied, Emily A; Larson, Gerald E; Galarneau, Michael R; Hammer, Paul S; Quinn, Kimberly H; Schmitz, Kimberly J; Webb-Murphy, Jennifer A; Boucher, Wayne C; Edwards, Nathan K; Ly, Hoa L

    2016-04-01

    The primary aim of this study was to evaluate whether being treated for mental health or nonbattle physical injury during military combat deployment was associated with higher risk for postdeployment mental disorders and poorer career outcomes than seen in the general combat-deployed population. Service members treated in theater for mental health (n = 964) or noncombat injury (n = 853) were compared with randomly sampled personnel (n = 7,220) from the general deployed population on diagnosed mental disorders and early separation from service. Deployment, medical, and career information were obtained from Department of Defense archival databases. Over half of the personnel who received mental health treatment while deployed were diagnosed with 1 or more mental disorders postdeployment and/or were separated from service before completing their full-term enlistment. This was significantly higher than expected compared to the general deployed group, adjusting for demographic/military characteristics and mental health history (adjusted odds ratios [ORs] ranging 1.62 to 2.96). Frequencies of problems also were higher in the mental health-treated group than in the group treated for nonbattle physical injuries (significant adjusted ORs ranging 1.65 to 2.58). The documented higher risks for postdeployment adjustment problems suggested that especially those treated in theater by mental health providers might benefit from postdeployment risk-reduction programs. PMID:26990003

  9. Comparison of usual podiatric care and early physical therapy intervention for plantar heel pain: study protocol for a parallel-group randomized clinical trial

    PubMed Central

    2013-01-01

    Background A significant number of individuals suffer from plantar heel pain (PHP) and many go on to have chronic symptoms and continued disability. Persistence of symptoms adds to the economic burden of PHP and cost-effective solutions are needed. Currently, there is a wide variation in treatment, cost, and outcomes of care for PHP with limited information on the cost-effectiveness and comparisons of common treatment approaches. Two practice guidelines and recent evidence of effective physical therapy intervention are available to direct treatment but the timing and influence of physical therapy intervention in the multidisciplinary management of PHP is unclear. The purpose of this investigation is to compare the outcomes and costs associated with early physical therapy intervention (ePT) following initial presentation to podiatry versus usual podiatric care (uPOD) in individuals with PHP. Methods A parallel-group, block-randomized clinical trial will compare ePT and uPOD. Both groups will be seen initially by a podiatrist before allocation to a group that will receive physical therapy intervention consisting primarily of manual therapy, exercise, and modalities, or podiatric care consisting primarily of a stretching handout, medication, injections, and orthotics. Treatment in each group will be directed by practice guidelines and a procedural manual, yet the specific intervention for each participant will be selected by the treating provider. Between-group differences in the Foot and Ankle Ability Measure 6 months following the initial visit will be the primary outcome collected by an independent investigator. In addition, differences in the European Quality of Life – Five Dimensions, Numeric Pain Rating Scale, Global Rating of Change (GROC), health-related costs, and cost-effectiveness at 6 weeks, 6 months, and 1 year will be compared between groups. The association between successful outcomes based on GROC score and participant expectations of recovery

  10. Results on diffraction at CDF

    SciTech Connect

    Wyatt, A.

    2003-10-27

    In run I CDF made an extensive range of measurements studying diffractive processes. In run II these measurements can be extended using improved triggering, new detectors and larger data samples. In these proceedings run II measurements of single diffractive dijet production and double pomeron exchange production of dijets are presented.

  11. Computer Simulation of Diffraction Patterns.

    ERIC Educational Resources Information Center

    Dodd, N. A.

    1983-01-01

    Describes an Apple computer program (listing available from author) which simulates Fraunhofer and Fresnel diffraction using vector addition techniques (vector chaining) and allows user to experiment with different shaped multiple apertures. Graphics output include vector resultants, phase difference, diffraction patterns, and the Cornu spiral…

  12. Muscle diffraction theory. Relationship between diffraction subpeaks and discrete sarcomere length distributions.

    PubMed Central

    Judy, M M; Summerour, V; LeConey, T; Roa, R L; Templeton, G H

    1982-01-01

    A theoretical discussion is presented that describes the diffraction on monochromatic light by a three-dimensional sarcomere array having the following properties. The basic repetitive diffracting unit is the sarcomere. The contiguous arrangement of physically attached serial sarcomeres in the myofibril is contained within the model so that relative position of sarcomeres depend upon the lengths of intervening ones. Sarcomere length is described by a distribution function. This function may be discrete or continuous and contain one or more subpopulations. Two arrangements of sarcomeres are considered: (a) when sarcomeres of different lengths are arranged randomly in myofibrils the amplitude and width of mth order (m greater than or equal to 1) peaks and associated secondary diffraction maxima decrease and increase monotonically, respectively, as the standard deviation of the length distribution increases. No subpeaks are present regardless of the number of subpopulations within the distribution function. This behavior is shown to follow from the dependence of sarcomere position on the length of intervening sarcomeres. (b) When sarcomeres belonging to the same length subpopulation are arranged in serial contiguous fashion to form domains and more than one length subpopulation is present, then mth order diffraction peaks split to form subpeaks. The theoretical basis for this behavior is developed for the first time and may explain the subpeaks evident in diffraction patterns from cardiac and skeletal muscle. PMID:7059651

  13. Mode control of semiconductor laser with diffraction and dispersion feedback

    SciTech Connect

    Xu, G.; Tsuji, R.; Fujii, K.; Nakayama, S.; Amano, M.; Kiyono, H.; Uchiyama, Y.; Tokita, Y.; Hanasawa, Y.; Mirov, S.B.; McCutcheon, M.J.; Whinnery, J.R.

    1996-05-01

    We have constructed two kinds of external cavity semiconductor laser. The first one is a diffraction feedback system consisting of a collimating lens, a diffraction grating and a mirror controlled by a PZT element. The second one is a dispersion feedback system in which the diffraction grating is replaced with a prism. Changing the angle of the external mirror by controlling the voltage to be supplied to the PZT, we have succeeded to tune the longitudinal mode of semiconductor laser continuously in the range of about 1 GHz. {copyright} {ital 1996 American Institute of Physics.}

  14. Early maternal age at first birth is associated with chronic diseases and poor physical performance in older age: cross-sectional analysis from the International Mobility in Aging Study

    PubMed Central

    2014-01-01

    Background Early maternal age at first birth and elevated parity may have long-term consequences for the health of women as they age. Both are known risk factors for obstetrical complications with lifelong associated morbidities. They may also be related to diabetes and cardiovascular disease development. Methods We examine the relationship between early maternal age at first birth, defined as ≤18 years of age, multiparity (>2 births), and poor physical performance (Short Physical Performance Battery ≤8) in community samples of women between 65 and 74 years of age from Canada, Albania, Colombia, and Brazil (N = 1040). Data were collected in 2012 to provide a baseline assessment for a longitudinal cohort called the International Mobility in Aging Study. We used logistic regression and general linear models to analyse the data. Results Early maternal age at first birth is significantly associated with diabetes, chronic lung disease, high blood pressure, and poor physical performance in women at older ages. Parity was not independently associated with chronic conditions and physical performance in older age. After adjustment for study site, age, education, childhood economic adversity and lifetime births, women who gave birth at a young age had 1.75 (95% CI: 1.17 – 2.64) the odds of poor SPPB compared to women who gave birth > 18 years of age. Adjustment for chronic diseases attenuated the association between early first birth and physical performance. Results were weaker in Colombia and Brazil, than Canada and Albania. Conclusions This study provides evidence that adolescent childbirth may increase the risk of developing chronic diseases and physical limitations in older age. Results likely reflect both the biological and social consequences of early childbearing and if the observed relationship is causal, it reinforces the importance of providing contraception and sex education to young women, as the consequences of early pregnancy may be life

  15. Diffraction of walking droplets

    NASA Astrophysics Data System (ADS)

    Harris, Daniel M.; Pucci, Giuseppe; Bush, John W. M.

    2014-11-01

    We present results from our revisitation of the experiment of a walking droplet passing through a single slit, originally investigated by Couder & Fort (PRL, 2006). On each passage, the walker's trajectory is deviated as a result of the spatial confinement of its guiding wave. We explore the role of the droplet size and the bath's vibration amplitude on both the dynamics and statistics. We find the behavior to be remarkably sensitive to these control parameters. A complex physical picture emerges. The authors gratefully acknowledge the financial support of the NSF through Grant CMMI-1333242, DMH through the NSF Graduate Research Fellowship Program, and GP through the Programma Operativo Regionale (POR) Calabria - FSE 2007/2013.

  16. Keyhole electron diffractive imaging (KEDI).

    PubMed

    De Caro, Liberato; Carlino, Elvio; Vittoria, Fabio Alessio; Siliqi, Dritan; Giannini, Cinzia

    2012-11-01

    Electron diffractive imaging (EDI) relies on combining information from the high-resolution transmission electron microscopy image of an isolated kinematically diffracting nano-particle with the corresponding nano-electron diffraction pattern. Phase-retrieval algorithms allow one to derive the phase, lost in the acquisition of the diffraction pattern, to visualize the actual atomic projected potential within the specimen at sub-ångström resolution, overcoming limitations due to the electron lens aberrations. Here the approach is generalized to study extended crystalline specimens. The new technique has been called keyhole electron diffractive imaging (KEDI) because it aims to investigate nano-regions of extended specimens at sub-ångström resolution by properly confining the illuminated area. Some basic issues of retrieving phase information from the EDI/KEDI measured diffracted amplitudes are discussed. By using the generalized Shannon sampling theorem it is shown that whenever suitable oversampling conditions are satisfied, EDI/KEDI diffraction patterns can contain enough information to lead to reliable phase retrieval of the unknown specimen electrostatic potential. Hence, the KEDI method has been demonstrated by simulations and experiments performed on an Si crystal cross section in the [112] zone-axis orientation, achieving a resolution of 71 pm. PMID:23075611

  17. Electromagnetic diffraction efficiencies for plane reflection diffraction gratings

    NASA Technical Reports Server (NTRS)

    Marathay, A. S.; Shrode, T. E.

    1973-01-01

    Results are presented of research activities on holographic grating research. A large portion of this work was performed using rigorous vector diffraction theory, therefore, the necessary theory has been included in this report. The diffraction efficiency studies were continued using programs based on a rigorous theory. The simultaneous occurrence of high diffraction efficiencies and the phenomenon of double Wood's anomalies is demonstrated along with a graphic method for determining the necessary grating parameters. Also, an analytical solution for a grating profile that is perfectly blazed is obtained. The performance of the perfectly blazed grating profile is shown to be significantly better than grating profiles previously studied. Finally, a proposed method is described for the analysis of coarse echelle gratings using rigorous vector diffraction that is currently being developed.

  18. Diffraction dissociation at the LHC

    NASA Astrophysics Data System (ADS)

    Jenkovszky, László; Orava, Risto; Salii, Andrii

    2013-04-01

    We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

  19. Diffraction dissociation at the LHC

    SciTech Connect

    Jenkovszky, Laszlo; Orava, Risto; Salii, Andrii

    2013-04-15

    We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

  20. Mothers’ perceptions of the UK physical activity and sedentary behaviour guidelines for the early years (Start Active, Stay Active): a qualitative study

    PubMed Central

    Bentley, Georgina F; Jago, Russell; Turner, Katrina M

    2015-01-01

    Objectives Higher levels of physical activity (PA) during early childhood have been associated with improved health outcomes, whereas sedentary behaviour (SB) has been associated with poorer health outcomes in children. In 2011, the UK produced guidelines for PA and SB in children under 5 years. Mothers have been identified as key influences in young children's PA and SB. The aim of this study was to use in-depth interviews with mothers of preschool children to examine attitudes to the guidance. Design Qualitative study using one-to-one, semistructured interviews; Data were analysed thematically using a framework approach. Setting Mothers were recruited from preschools, nurseries, and mother and toddler groups located in four areas of varying socioeconomic status within Bristol, UK. Participants 24 mothers who were considered the main or joint carer for a preschool child who was at least 2 years of age but had not yet started formal schooling. Results Mothers are not aware of the UK PA and SB guidelines for the early years. They believe that their child achieves the guideline targets for PA and SB and therefore, they do not believe these quidelines are relevant to them. Mothers feel that an increase in PA and reduction in SB (especially screen-viewing) would cause stress for mothers. Mothers found defining and quantifying PA and SB in their preschool child problematic. Conclusions As mothers do not identify with the need to increase PA or reduce SB in their child, awareness of the guidelines alone is unlikely to initiate behaviour change. Information on how mothers can make a more accurate assessment of their preschool child's PA and SB levels, and information about the benefits of increased PA and reduced SB should be provided alongside the guideline targets. Clear messages need to be developed that reframe the guidelines into pragmatic and usable targets. PMID:26351186

  1. Prototyping an Early-warning System for Rainfall-triggered Landslides on a Regional Scale Using a Physically-based Model and Remote Sensing Datasets

    NASA Astrophysics Data System (ADS)

    Liao, Z.; Hong, Y.; Kirschbaum, D. B.; Fukuoka, H.; Sassa, K.; Karnawati, D.; Fathani, F.

    2010-12-01

    Recent advancements in the availability of remotely sensed datasets provide an opportunity to advance the predictability of rainfall-triggered landslides at larger spatial scales. An early-warning system based on a physical landslide model and remote sensing information is used to simulate the dynamical response of the soil water content to the spatiotemporal variability of rainfall in complex terrain. The system utilizes geomorphologic datasets including a 30-meter ASTER DEM, a 1-km downscaled FAO soil map, and satellite-based Tropical Rainfall Measuring Mission (TRMM) precipitation. The applied physical model SLIDE (SLope-Infiltration-Distributed Equilibrium) defines a direct relationship between a factor of safety and the rainfall depth on an infinite slope. This prototype model is applied to a case study in Honduras during Hurricane Mitch in 1998 and a secondary case of typhoon-induced shallow landslides over Java Island, Indonesia. In Honduras, two study areas were selected which cover approximately 1,200 square kilometers and where a high density of shallow landslides occurred. The results were quantitatively evaluated using landslide inventory data compiled by the United States Geological Survey (USGS) following Hurricane Mitch, and show a good agreement between the modeling results and observations. The success rate for accurately estimating slope failure locations reached as high as 78% and 75%, while the error indices were 35% and 49%, respectively for each of the two selected study areas. Advantages and limitations of this application are discussed with respect to future assessment and challenges of performing a slope-stability estimation using coarse data at 1200 square kilometers. In Indonesia, the system has been applied over the whole Java Island. The prototyped early-warning system has been enhanced by integration of a susceptibility mapping and a precipitation forecasting model (i.e. Weather Research Forecast). The performance has been evaluated

  2. Very Early Prescient Experimental and Theoretical Nano/Microcluster-Scale-Physics Root-Cause Ultimate-Origins: History: EMET!!!/TRUTH!!!

    NASA Astrophysics Data System (ADS)

    Gregson, Victor; Kubo, Ryogiro; Siegel, Edward Carl-Ludwig

    2013-03-01

    Siegel[Phys.Stat.Sol.(a)11,45(72)] possibly first experimental nanoscale-physics/metallurgy/ceramics(VS CNRS Mdm.-Pres.resume-claims),following always-seminal Kubo[Phys. Lett.1,49(62);J.Phys.Soc.Jpn.:17,965(62); 21,1765(66); Comm.SS Phys.1,168 (68); J.Phys.Colloques,38,C2-69(77).]-Fulde[(1960s)]-Matsubara et. al.[(1960s]-Matsubara-Siegel[Intl.Conf.Lattice-Dym.(77);Statphys-13(77);ICMAO(77);Scripta Met.13,913(79)] as reviewed by Sugano[Microcluster-Physics(81)], very early experimental hardness/bulk-modului/shear-moduli versus/ connection to Dempsey[Phil.Mag. 8,86,285(63)] electrical-resistivity trends with cation-atomic-number of hot/cold-pressed ceramics versus Mott topological-disorder: Siegel: powders[Mtls.Sci.Eng.8,6 323(71);Phys.Stat.Sol.(a)11, 45(72) ;Semis, &Insuls.5:39,47,62 (79)] /glasses[J.Nonxline-Sols.40,453(80); NYAS Conf.Atomic & Molecular Glasses, Ann.NYAS(80); Ferroelectrics 34,1,127(81)]/ liquids[Phys.& Chem.Liqs.:4(4)(75);5(1)(76)] / slushes (!!!)/ blends /ferrofluids[Intl Conf. Ferrofluids, M. Zahn ed.(84)]/nanophysics of Goudschmidt [Interstitial-Alloys,(69)] transition-metalloids: carbides, nitrides, borides, hydrides, carbon [Phys.Stat.Sol.(a)11,45(72); Semis.&Insuls.5: 39,47,62(79)]) and proton-irradiated diamond Little[(1960s]-predicted hyper/superconducting polydiacetylene(???) quantum-wires [3rd World Cong.SC, Munich(92), Appl.-SC,1,10,1949(93); TWO OTHER PAPERS SPIKED BY ANL/DOE EDITORS!!! AS USUAL!!!: GOOGLE:

  3. Diffracting the rays of technoscience: a situated critique of representation.

    PubMed

    Timeto, Federica

    2011-12-01

    This essay focuses on the possibility of adopting a representational approach for technoscience, in which representation is considered as a situated process of dynamic "intra-action" (Barad 2007). Re-elaborating the recent critiques of representationalism (Thrift 2008), my analysis begins by analysing Hayles's situated model of representation from an early essay where she explains her definition of constrained constructivism (Hayles [1991] 1997). The essay then discusses the notions of figuration and diffraction and the way they are employed by Haraway in many of her writings for her critique of technoscience (Haraway 1991, 1997). Finally, after considering diffraction through Barad's reading of this practice in the context of her theory of agential realism (2007), it shows the links that relate constrained constructivism, situated knowledge and agential realism, and the way all of them work at "diffract[ing] the rays of technoscience" (Haraway 1997: 16) through an alternative representational practice. PMID:22207831

  4. X-Ray Diffraction Apparatus

    NASA Technical Reports Server (NTRS)

    Blake, David F. (Inventor); Bryson, Charles (Inventor); Freund, Friedmann (Inventor)

    1996-01-01

    An x-ray diffraction apparatus for use in analyzing the x-ray diffraction pattern of a sample is introduced. The apparatus includes a beam source for generating a collimated x-ray beam having one or more discrete x-ray energies, a holder for holding the sample to be analyzed in the path of the beam, and a charge-coupled device having an array of pixels for detecting, in one or more selected photon energy ranges, x-ray diffraction photons produced by irradiating such a sample with said beam. The CCD is coupled to an output unit which receives input information relating to the energies of photons striking each pixel in the CCD, and constructs the diffraction pattern of photons within a selected energy range striking the CCD.

  5. Femtosecond single-electron diffraction

    PubMed Central

    Lahme, S.; Kealhofer, C.; Krausz, F.; Baum, P.

    2014-01-01

    Ultrafast electron diffraction allows the tracking of atomic motion in real time, but space charge effects within dense electron packets are a problem for temporal resolution. Here, we report on time-resolved pump-probe diffraction using femtosecond single-electron pulses that are free from intra-pulse Coulomb interactions over the entire trajectory from the source to the detector. Sufficient average electron current is achieved at repetition rates of hundreds of kHz. Thermal load on the sample is avoided by minimizing the pump-probe area and by maximizing heat diffusion. Time-resolved diffraction from fibrous graphite polycrystals reveals coherent acoustic phonons in a nanometer-thick grain ensemble with a signal-to-noise level comparable to conventional multi-electron experiments. These results demonstrate the feasibility of pump-probe diffraction in the single-electron regime, where simulations indicate compressibility of the pulses down to few-femtosecond and attosecond duration. PMID:26798778

  6. Electrically-programmable diffraction grating

    DOEpatents

    Ricco, A.J.; Butler, M.A.; Sinclair, M.B.; Senturia, S.D.

    1998-05-26

    An electrically-programmable diffraction grating is disclosed. The programmable grating includes a substrate having a plurality of electrodes formed thereon and a moveable grating element above each of the electrodes. The grating elements are electrostatically programmable to form a diffraction grating for diffracting an incident beam of light as it is reflected from the upper surfaces of the grating elements. The programmable diffraction grating, formed by a micromachining process, has applications for optical information processing (e.g. optical correlators and computers), for multiplexing and demultiplexing a plurality of light beams of different wavelengths (e.g. for optical fiber communications), and for forming spectrometers (e.g. correlation and scanning spectrometers). 14 figs.

  7. Diffraction by random Ronchi gratings.

    PubMed

    Torcal-Milla, Francisco Jose; Sanchez-Brea, Luis Miguel

    2016-08-01

    In this work, we obtain analytical expressions for the near-and far-field diffraction of random Ronchi diffraction gratings where the slits of the grating are randomly displaced around their periodical positions. We theoretically show that the effect of randomness in the position of the slits of the grating produces a decrease of the contrast and even disappearance of the self-images for high randomness level at the near field. On the other hand, it cancels high-order harmonics in far field, resulting in only a few central diffraction orders. Numerical simulations by means of the Rayleigh-Sommerfeld diffraction formula are performed in order to corroborate the analytical results. These results are of interest for industrial and technological applications where manufacture errors need to be considered. PMID:27505363

  8. Estimating the Size of Onion Epidermal Cells from Diffraction Patterns

    NASA Astrophysics Data System (ADS)

    Groff, Jeffrey R.

    2012-10-01

    Bioscience and premedical profession students are a major demographic served by introductory physics courses at many colleges and universities. Exposing these students to biological applications of physical principles will help them to appreciate physics as a useful tool for their future professions. Here I describe an experiment suitable for introductory physics where principles of wave optics are applied to probe the size of onion epidermal cells. The epidermis tissue is composed of cells of relatively uniform size and shape (Fig. 1) so the tissue acts like a one-dimensional transmission diffraction grating. The diffraction patterns generated when a laser beam passes through the tissue (Fig. 2) are analyzed and an estimate of the average width of individual onion epidermal cells is calculated. The results are compared to direct measurements taken using a light microscope. The use of microscopes and plant-cell tissue slides creates opportunities for cross-discipline collaboration between physics and biology instructors.

  9. Fresnel diffraction by spherical obstacles

    NASA Technical Reports Server (NTRS)

    Hovenac, Edward A.

    1989-01-01

    Lommel functions were used to solve the Fresnel-Kirchhoff diffraction integral for the case of a spherical obstacle. Comparisons were made between Fresnel diffraction theory and Mie scattering theory. Fresnel theory is then compared to experimental data. Experiment and theory typically deviated from one another by less than 10 percent. A unique experimental setup using mercury spheres suspended in a viscous fluid significantly reduced optical noise. The major source of error was due to the Gaussian-shaped laser beam.

  10. Diffractive dijet production in CDF

    SciTech Connect

    Albrow, M.G.; CDF Collaboration

    1998-04-17

    We have studied events with a high-x{sub F} antiproton and two central jets in CDF, with p{anti p} collisions at {radical}s = 630 and 1800 GeV. These events are expected to be dominated by diffraction (pomeron exchange). The jet E{sub T} spectra are very similar to those of non-diffractively produced jets but slightly steeper; their azimuthal difference {Delta}{phi} is more peaked at 180{degree}.

  11. New CDF results on diffraction

    SciTech Connect

    Mesropian, Christina; /Rockefeller U.

    2006-12-01

    We report new diffraction results obtained by the CDF collaboration in proton-antiproton collisions at the Fermilab Tevatron collider at {radical}s=1.96 TeV. The first experimental evidence of exclusive dijet and diphoton production is presented. The exclusive results are discussed in context of the exclusive Higgs production at LHC. We also present the measurement of the Q{sup 2} and t dependence of the diffractive structure function.

  12. Does physical interstimulus variance account for early electrophysiological face sensitive responses in the human brain? Ten lessons on the N170.

    PubMed

    Rossion, Bruno; Jacques, Corentin

    2008-02-15

    A recent event-related potential (ERP) study (Thierry G., Martin, C.D., Downing, P., Pegna, A.J. 2007. Controlling for interstimulus perceptual variance abolishes N170 face selectivity. Nature Neuroscience, 10, 505-11) claimed that the larger occipito-temporal N170 response to pictures of faces than other categories -- the N170 effect -- is due to a methodological artifact in stimulus selection, specifically, a greater interstimulus physical variance between pictures of objects than faces in previous ERP studies which, when controlled, eliminates this N170 effect. This statement casts doubts on the validity of the conclusions reached by a whole tradition of electrophysiological experiments published over the past 15 years and questions the very interest of using the N170 to probe the time course of face processes in the human brain. Here we claim that this physical variance factor is ill-defined by Thierry et al. and cannot account for previous observations of a smaller N170 amplitude to nonface objects than faces without latency increase and component "smearing". Most importantly, this factor was controlled in previous studies that reported robust N170 effects. We demonstrate that the absence of N170 effect in the study of Thierry et al. is due to methodological flaws in the reported experiments, most notably measuring the N170 at the wrong electrode sites. Moreover, the authors attributed a modulation of N170 amplitude in their study to a differential interstimulus physical variance while it probably reflects a biased comparison of different quality sets of individual images. Here, by taking Thierry et al.'s study as an exemplar case of what should not be done in ERP research of visual categorization processes, we provide clarifications on a number of methodological and theoretical issues about the N170 and its largest amplitude to faces. More generally, we discuss the potential role of differential visual homogeneity of object categories as well as low

  13. The Growth of Thin Epitaxial Copper Films on Ruthenium (0001)and Oxygen-Precovered Ruthenium (0001) as studied by x-rayphotoelectron diffraction. University of California, Davis, Department of Physics, Ph.D. Thesis

    SciTech Connect

    Ruebush, Scott Daniel

    1997-06-01

    In the first part of this dissertation, the variation of mean emitter depths with direction for core photoelectron emission from single crystals, including the effects of both isotropic inelastic scattering and single and multiple elastic scattering was theoretically studied. The mean emitter depth was found to vary by as much as ±30% with direction. In the second part of this dissertation, x-ray photoelectron diffraction (XPD) was used to study the structure and growth mechanisms of Cu films grown on a clean and an oxygen-precovered Ru(OOO1) surface. Experimental Cu 2p3/2 (Ekin = 556 eV) and Ru 3d (Ekin = 1205 eV) intensities were measured for Cu coverages from submonolayer up to several monolayer (ML) on the clean Ru(OOO1) surface. In addition, the O 1s (Ekin = 958 eV) intensity was measured for Cu grown on oxygen precovered Ru(OOO1). These XPD intensities have been analyzed using single scattering cluster (SSC) and multiple scattering cluster (MSC) models. The first Cu layer has been found to grow pseudomorphically on the Ru(OOO1) surface in agreement with prior studies of the Cu/Ru(OOO 1) system. Thus, the initial growth is layer-by-layer. For higher coverages, XPD shows that the short-range structure of the Cu films is fcc Cu(l 11), but with significant interlayer relaxation (compared to bulk Cu(l 11)) that persists up to {ge}8 ML. When oxygen is preadsorbed on the Ru(OOO1) surface before Cu film growth (possibly to act as a surfactant promoting smoother growth), XPD shows that the first ~3 ML of Cu grow as 3-D islands. In addition, XPD shows that, during Cu growth, all of the oxygen "floats" on the CU surface, in contrast to prior studies which found that 30% of the oxygen remains at the Cu/Ru intetiace. XPD also indicates that the oxygen is highly disordered on the Cu overlayer surface. In thicker layers with oxygen prsent, the Cu grows as Cu(l 11) with equal occupations of two possible domains rotated by 1800 from each

  14. Diffraction efficiency analysis for multi-level diffractive optical elements

    SciTech Connect

    Erteza, I.A.

    1995-11-01

    Passive optical components can be broken down into two main groups: Refractive elements and diffractive elements. With recent advances in manufacturing technologies, diffractive optical elements are becoming increasingly more prevalent in optical systems. It is therefore important to be able to understand and model the behavior of these elements. In this report, we present a thorough analysis of a completely general diffractive optical element (DOE). The main goal of the analysis is to understand the diffraction efficiency and power distribution of the various modes affected by the DOE. This is critical to understanding cross talk and power issues when these elements are used in actual systems. As mentioned, the model is based on a completely general scenario for a DOE. This allows the user to specify the details to model a wide variety of diffractive elements. The analysis is implemented straightforwardly in Mathematica. This report includes the development of the analysis, the Mathematica implementation of the model and several examples using the Mathematical analysis tool. It is intended that this tool be a building block for more specialized analyses.

  15. On the representation of the diffracted field of Hermite-Gaussian modes in an alien basis and the young diffraction principle

    SciTech Connect

    Smirnov, V.N.; Strokovskii, G.A.

    1994-10-01

    An analytical form of expansion coefficients of a diffracted field for an arbitrary Hermite-Gaussian beam in an alien Hermite-Gaussian basis is obtained. A possible physical interpretation of the well-known Young phenomenological diffraction principle and experiments on diffraction of Hermite-Gaussian beams of the lowest types (n = 0 - 5) from half-plane are discussed. The case of nearly homogenous expansion corresponding to misalignment and mismatch of optical systems is also analyzed. 7 refs., 2 figs.

  16. Daily Physical Activity Assessed by a Triaxial Accelerometer Is Beneficially Associated with Waist Circumference, Serum Triglycerides, and Insulin Resistance in Japanese Patients with Prediabetes or Untreated Early Type 2 Diabetes

    PubMed Central

    Hamasaki, Hidetaka; Noda, Mitsuhiko; Moriyama, Sumie; Yoshikawa, Reo; Katsuyama, Hisayuki; Sako, Akahito; Mishima, Shuichi; Kakei, Masafumi; Ezaki, Osamu; Yanai, Hidekatsu

    2015-01-01

    Aim. To investigate the association between daily physical activity and metabolic risk factors in Japanese adults with prediabetes or untreated early type 2 diabetes (T2D). Methods. Daily physical activity level was measured using a triaxial accelerometer. We assessed correlations between physical activity level and waist circumference, blood pressure, fasting levels of plasma glucose, serum triglycerides, and insulin and homeostasis model assessment-insulin resistance (HOMA-IR). Results. A total of 80 patients were studied. After adjustment for age and body mass index, in all subjects, physical activity level was negatively associated with waist circumference (β = −0.124, P = 0.018) and fasting serum triglycerides (β = −0.239, P = 0.035), insulin (β = −0.224, P = 0.022). In men, physical activity level was negatively associated with systolic blood pressure (β = −0.351, P = 0.044), fasting plasma glucose (β = −0.369, P = 0.025) and insulin (β = −0.362, P = 0.012), and HOMA-IR (β = −0.371, P = 0.011). No significant associations were found between physical activity level and metabolic risk factors in women. Conclusion. Objectively measured daily physical activity is beneficially associated with waist circumference, serum triglycerides, and insulin resistance in individuals with prediabetes or untreated early T2D. (This trial is registered with UMIN000015774.) PMID:26064983

  17. Diffraction described by virtual particle momentum exchange: the "diffraction force"

    NASA Astrophysics Data System (ADS)

    Mobley, Michael J.

    2011-09-01

    Particle diffraction can be described by an ensemble of particle paths determined through a Fourier analysis of a scattering lattice where the momentum exchange probabilities are defined at the location of scattering, not the point of detection. This description is compatible with optical wave theories and quantum particle models and provides deeper insights to the nature of quantum uncertainty. In this paper the Rayleigh-Sommerfeld and Fresnel-Kirchoff theories are analyzed for diffraction by a narrow slit and a straight edge to demonstrate the dependence of particle scattering on the distance of virtual particle exchange. The quantized momentum exchange is defined by the Heisenberg uncertainty principle and is consistent with the formalism of QED. This exchange of momentum manifests the "diffraction force" that appears to be a universal construct as it applies to neutral and charged particles. This analysis indicates virtual particles might form an exchange channel that bridges the space of momentum exchange.

  18. Diffractive dissociation including Pomeron loops in zero transverse dimensions

    NASA Astrophysics Data System (ADS)

    Shoshi, Arif I.; Xiao, Bo-Wen

    2007-03-01

    We have recently studied the QCD pomeron loop evolution equations in zero transverse dimensions [Phys. Rev. D 73, 094014 (2006)PRVDAQ0556-282110.1103/PhysRevD.73.094014]. Using the techniques developed in [Phys. Rev. D 73, 094014 (2006)PRVDAQ0556-282110.1103/PhysRevD.73.094014] together with the AGK cutting rules, we present a calculation of single, double and central diffractive cross sections (for large diffractive masses and large rapidity gaps) in zero transverse dimensions in which all dominant pomeron loop graphs are consistently summed. We find that the diffractive cross sections unitarise at large energies and that they are suppressed by powers of αs. Our calculation is expected to expose some of the diffractive physics in hadron-hadron collisions at high energy.

  19. Coherent grating x-ray diffraction (CGXD) and its applications

    SciTech Connect

    Shen, Q.

    1996-09-01

    We show that an x-ray interference phenomenon, coherent grating x-ray diffraction (CGXD), can be used to study lateral nanostructure arrays on crystal surfaces and interfaces. Compared to Fraunhofer grating diffraction of visible light, x-ray grating diffraction contains information not only about geometric profiles of the surface but also about the internal crystalline structures and lattice strain distributions in the grating features. The grating diffraction pattern can also be measured in a white-beam Laue method using highly collimated polychromatic synchrotron radiation, which provides a parallel data collection scheme and may be useful in {ital in} {ital situ} studies on evolution of nanostructure arrays. {copyright} {ital 1996 American Institute of Physics.}

  20. Secondary diffraction of diffracted Gaussian beam of laser radiation

    NASA Astrophysics Data System (ADS)

    Vasil'Ev, Yu. V.; Kozar', A. V.; Matyunin, A. V.

    2011-10-01

    The diffraction of a narrow Gaussian beam of laser radiation on mutually perpendicular edges of crossed, superimposed sharp wedge-shaped blades (safety razors) has been studied. The diffraction pattern observed on a flat screen behind the blades comprises a very bright central spot, which exhibits the structure of a "light network" with rectangular cells, and four groups of narrow bright bands that expand from the central spot toward the periphery and form a rectangular cross. The spatial frequency of light-field modulation on the screen can be controlled by varying the distance from the blades to screen.

  1. Electromagnetic diffraction efficiencies for plane reflection diffraction gratings

    NASA Technical Reports Server (NTRS)

    Marathay, A. S.; Shrode, T. E.

    1974-01-01

    The theory and computer programs, based on electromagnetic theory, for the analysis and design of echelle gratings were developed. The gratings are designed for instruments that operate in the ultraviolet portion of the spectrum. The theory was developed so that the resulting computer programs will be able to analyze deep (up to 30 wavelengths) gratings by including as many as 100 real or homogeneous diffraction orders. The program calculates the complex amplitude coefficient for each of the diffracted orders. A check on the numerical method used to solve the integral equations is provided by a conservation of energy calculation.

  2. Levels of physical activity among a nationally representative sample of people in early old age: results of objective and self-reported assessments

    PubMed Central

    2014-01-01

    Background Detailed assessment of physical activity (PA) in older adults is required to comprehensively describe habitual PA-levels in this growing population segment. Current evidence of population PA-levels is predominantly based on self-report. Methods We examined PA and sedentary behaviour in a nationally representative sample of British people aged 60–64, using individually-calibrated combined heart-rate and movement sensing and a validated questionnaire (EPAQ2), and the socio-demographic and behavioural factors that may explain between-individual variation in PA. Results Between 2006–2010, 2224 participants completed EPAQ2 capturing the past year’s activity in four domains (leisure, work, transportation and domestic life) and 1787 participants provided 2–5 days of combined-sensing data. According to objective estimates, median(IQR) physical activity energy expenditure (PAEE) was 33.5 (25.3-42.2) and 35.5 (26.6- 47.3) kJ/kg/day for women and men, respectively. Median (IQR) time spent in moderate-to-vigorous PA (MVPA; >3MET), light-intensity PA (1.5-3 MET) and sedentary (<1.5 MET) was 26.0 (12.3-48.1) min/day, 5.4 (4.2-6.7) h/day and 18.0 (16.6-19.4) h/day, respectively, in women; and 41.0 (18.8-73.0) min/day, 5.2 (4.0-6.5) h/day and 17.9 (16.3-19.4) h/day in men. PAEE and time spent in MVPA were lower and sedentary time was greater in obese individuals, those with poor health, and those with lower educational attainment (women only). Questionnaire-derived PAEE and MVPA tended to have similar patterns of variation across socio-demographic strata. In the whole sample, domestic PA had the greatest relative contribution to total questionnaire-derived PAEE (58%), whereas occupational PA was the main driver among employed participants (54%). Only 2.2% of participants achieved an average of >30 min MVPA per day combined with >60 min strength-training per week. Conclusions The use of both self-report and objective monitoring to assess PA in early old age

  3. Lensless reflective point diffraction interferometer.

    PubMed

    Zhu, Wenhua; Chen, Lei; Zheng, Donghui; Yang, Ying; Han, Zhigang; Li, Jinpeng

    2016-07-01

    A lensless reflective point diffraction interferometer (LRPDI) is proposed for dynamic wavefront measurement. The point diffraction interferometer is integrated on a small substrate with properly designed thin film, which is used for generating the interferogram with high carrier frequency at a CCD target. By lensless imaging, the complex amplitude at the CCD target can be propagated to the conjugated plane of the exit pupil of an incident wavefront, which not only avoids the edge diffraction in the interferogram, but also eliminates systematic error. The accuracy of LRPDI is demonstrated by simulation and experiment, and a precision better than 1/150 wavelength is achieved. The new design with lensless imaging processing is suitable for dynamic wavefront measurement. PMID:27409204

  4. Electron diffraction by plasmon waves

    NASA Astrophysics Data System (ADS)

    García de Abajo, F. J.; Barwick, B.; Carbone, F.

    2016-07-01

    An electron beam traversing a structured plasmonic field is shown to undergo diffraction with characteristic angular patterns of both elastic and inelastic outgoing electron components. In particular, a plasmonic grating (e.g., a standing wave formed by two counterpropagating plasmons in a thin film) produces diffraction orders of the same parity as the net number of exchanged plasmons. Large diffracted beam fractions are predicted to occur for realistic plasmon intensities in attainable geometries due to a combination of phase and amplitude changes locally imprinted on the passing electron wave. Our study opens vistas in the study of multiphoton exchanges between electron beams and evanescent optical fields with unexplored effects related to the transversal component of the electron wave function.

  5. Boundary diffraction wave integrals for diffraction modeling of external occulters.

    PubMed

    Cady, Eric

    2012-07-01

    An occulter is a large diffracting screen which may be flown in conjunction with a telescope to image extrasolar planets. The edge is shaped to minimize the diffracted light in a region beyond the occulter, and a telescope may be placed in this dark shadow to view an extrasolar system with the starlight removed. Errors in position, orientation, and shape of the occulter will diffract additional light into this region, and a challenge of modeling an occulter system is to accurately and quickly model these effects. We present a fast method for the calculation of electric fields following an occulter, based on the concept of the boundary diffraction wave: the 2D structure of the occulter is reduced to a 1D edge integral which directly incorporates the occulter shape, and which can be easily adjusted to include changes in occulter position and shape, as well as the effects of sources-such as exoplanets-which arrive off-axis to the occulter. The structure of a typical implementation of the algorithm is included. PMID:22772218

  6. Distributed etched diffraction grating demultiplexer

    NASA Astrophysics Data System (ADS)

    Jafari, Amir

    This doctoral thesis studies the concept of a distributed etched diffraction grating (DEDG) and presents a methodology to engineer the spectral response of the device. The design which incorporates a distributed Bragg reflector (DBR) at the facets of a conventional etched diffraction grating demultiplexer promises for a superior performance in multiple aspects. Where in a conventional etched diffraction grating, smooth vertical deep etched walls are required in order to realize a low insertion loss device; in the DEDG such requirement is significantly mitigated. Deep etched walls are replaced with shallowly etched diffraction grating facets followed by a DBR structure and as a result devices with significantly lower insertion loss are achievable. The feasibility of the application of DEDG as a wavelength demultiplexer was demonstrated through fabrication and characterization of a prototype device. The proof of concept device was fabricated using the state of the art deep UV optical lithography and reactive ion etching in a nano-photonic silicon-on-insulator (SOI) material platform. The fabricated device was then characterized in the lab. Furthermore, incorporation of the DBR structure at the facets of the conventional etched diffraction grating decouples the reflection and diffraction functionalities, rendering the DEDG suitable for spectral response engineering. According to the application, the output spectral response of the device can be tailored through careful design and optimization of the incorporated DBR. In this thesis, through numerical simulations we have shown that functionalities such as polarization independent performance and at top insertion loss envelop are viable. A methodology to engineer the spectral response of the DEDG is discussed in details.

  7. Detonation diffraction through different geometries

    NASA Astrophysics Data System (ADS)

    Sorin, Rémy; Zitoun, Ratiba; Khasainov, Boris; Desbordes, Daniel

    2009-04-01

    We performed the study of the diffraction of a self-sustained detonation from a cylindrical tube (of inner diameter d) through different geometric configurations in order to characterise the transmission processes and to quantify the transmission criteria to the reception chamber. For the diffraction from a tube to the open space the transmission criteria is expressed by d c = k c · λ (with λ the detonation cell size and k c depending on the mixture and on the operture configuration, classically 13 for alkane mixtures with oxygen). The studied geometries are: (a) a sharp increase of diameter ( D/ d > 1) with and without a central obstacle in the diffracting section, (b) a conical divergent with a central obstacle in the diffracting section and (c) an inversed intermediate one end closed tube insuring a double reflection before a final diffraction between the initiator tube and the reception chamber. The results for case A show that the reinitiation process depends on the ratio d/ λ. For ratios below k c the re-ignition takes place at the receptor tube wall and at a fixed distance from the step, i.e. closely after the diffracted shock reflection shows a Mach stem configuration. For ratios below a limit ratio k lim (which depends on D/ d) the re-ignition distance increases with the decrease of d/λ. For both case A and B the introduction of a central obstacle (of blockage ratio BR = 0.5) at the exit of the initiator tube decreases the critical transmission ratio k c by 50%. The results in configuration C show that the re-ignition process depends both on d/ λ and the geometric conditions. Optimal configuration is found that provides the transmission through the two successive reflections (from d = 26 mm to D ch = 200 mm) at as small d/ λ as 2.2 whatever the intermediate diameter D is. This configuration provides a significant improvement in the detonation transmission conditions.

  8. Identification of domains within the human cytomegalovirus major immediate-early 86-kilodalton protein and the retinoblastoma protein required for physical and functional interaction with each other.

    PubMed Central

    Fortunato, E A; Sommer, M H; Yoder, K; Spector, D H

    1997-01-01

    The human cytomegalovirus major immediate-early 86-kDa protein (IE2 86) plays an important role in the trans activation and regulation of HCMV gene expression. Previously, we demonstrated that IE2 86 contains three regions (amino acids [aa] 86 to 135, 136 to 290, and 291 to 364) that can independently bind to in vitro-translated Rb when IE2 86 is produced as a glutathione S-transferase fusion protein (M. H. Sommer, A. L. Scully, and D. H. Spector, J. Virol. 68:6223-6231, 1994). In this report, we have elucidated the regions of Rb involved in binding to IE2 86 and have further analyzed the functional nature of the interaction between these two proteins. We find that two domains on Rb, the A/B pocket and the carboxy terminus, can each independently form a complex with IE2 86. In functional assays, we demonstrate that IE2 86 and another IE protein, IE1 72, can counter the enlarged flat cell phenotype, but not the G1/S block, which results from expression of wild-type Rb in the human osteosarcoma cell line Saos-2. Mutational analysis reveals that there are two domains on IE2 86 that can independently affect Rb function. One region (aa 241 to 369) includes the major Rb-binding domain, while the second maps to the amino-terminal region (aa 1 to 85) common to both IE2 86 and IE1 72. These data show that Rb and IE2 86 physically and functionally interact with each other via at least two separate domains and provide further support for the hypothesis that IE2 86 may exert its pleiotropic effects through the formation of multimeric protein complexes. PMID:9343168

  9. Neutron diffraction on pulsed sources

    NASA Astrophysics Data System (ADS)

    Aksenov, V. L.; Balagurov, A. M.

    2016-03-01

    The current capabilities of and major scientific problems solved by time-of-flight neutron diffraction are reviewed. The reasons for the rapid development of the method over the last two decades have been mainly the emergence of third-generation pulsed sources with a megawatt time-averaged power and advances in neutron optical devices and detector systems. The paper discusses some historical aspects of time-of-flight neutron diffraction and examines the contribution to this method from F L Shapiro, the centennial of whose birth was celebrated in 2015. The state of the art with respect to neutron sources for studies on extracted beams is reviewed in a special section.

  10. High-pressure neutron diffraction

    SciTech Connect

    Xu, Hongwu

    2011-01-10

    This lecture will cover progress and prospect of applications of high-pressure neutron diffraction techniques to Earth and materials sciences. I will first introduce general high-pressure research topics and available in-situ high-pressure techniques. Then I'll talk about high-pressure neutron diffraction techniques using two types of pressure cells: fluid-driven and anvil-type cells. Lastly, I will give several case studies using these techniques, particularly, those on hydrogen-bearing materials and magnetic transitions.

  11. Diffraction encoded position measuring apparatus

    DOEpatents

    Tansey, Richard J.

    1991-01-01

    When a lightwave passes through a transmission grating, diffracted beams appear at the output or opposite side of the grating that are effectively Doppler shifted in frequency (phase) whereby a detector system can compare the phase of the zero order and higher order beams to obtain an indication of position. Multiple passes through the grating increase resolution for a given wavelength of a laser signal. The resolution can be improved further by using a smaller wavelength laser to generate the grating itself. Since the grating must only have a pitch sufficient to produce diffracted orders, inexpensive, ultraviolet wavelength lasers can be utilized and still obtain high resolution detection.

  12. Diffraction encoded position measuring apparatus

    DOEpatents

    Tansey, R.J.

    1991-09-24

    When a lightwave passes through a transmission grating, diffracted beams appear at the output or opposite side of the grating that are effectively Doppler shifted in frequency (phase) whereby a detector system can compare the phase of the zero order and higher order beams to obtain an indication of position. Multiple passes through the grating increase resolution for a given wavelength of a laser signal. The resolution can be improved further by using a smaller wavelength laser to generate the grating itself. Since the grating must only have a pitch sufficient to produce diffracted orders, inexpensive, ultraviolet wavelength lasers can be utilized and still obtain high resolution detection. 3 figures.

  13. Ellipsometry of diffractive insect reflectors

    NASA Astrophysics Data System (ADS)

    Brink, D. J.; Lee, M. E.

    1996-04-01

    Scales on the wings of certain insects, such as Trichoplusia orichalcea, exhibit a surface microstructure resembling a fine diffraction grating. Diffraction of incident light by this structure is responsible for many of the optical properties of the wings of this moth, such as the metallic yellow color and the almost-specular reflection and polarization properties of the scattered radiation. It is shown that by the use of null ellipsometry the polarization characteristics can be used to obtain the optical constants of the scale material. Theoretical considerations and suitable experimental conditions are discussed and evaluated.

  14. Subwavelength diffractive color beam combiner.

    PubMed

    Petrov, Nikolai I; Nikitin, Vladislav G; Danilov, Viktor A; Popov, Vladimir V; Usievich, Boris A

    2014-09-01

    A high-efficiency subwavelength diffractive beam combiner operating in a visible spectral range is designed, fabricated, and demonstrated. Such a device combines red, green, and blue color beams into one output light beam. Diffraction efficiencies of different types of gratings are calculated for various materials, incidence angles, and polarizations of light. It is shown that the plasmon resonance via a grating coupling occurs at the determined conditions. Subwavelength gratings with a period of 400 nm are fabricated and tested using laser and laser diode sources. PMID:25321371

  15. Teaching diffraction with hands-on optical spectrometry

    NASA Astrophysics Data System (ADS)

    Fischer, Robert

    2012-09-01

    Although the observation of optical spectra is common practice in physics classes, students are usually limited to a passive, qualitative observation of nice colours. This paper discusses a diffraction-based spectrometer that allows students to take quantitative measurements of spectral bands. Students can build it within minutes from generic low-cost materials. The spectrometer’s simple, didactic design allows students to fully comprehend the underlying physical concepts and to engage in a discussion of measurement errors and uncertainties.

  16. Diffraction by DNA, carbon nanotubes and other helical nanostructures

    NASA Astrophysics Data System (ADS)

    Lucas, Amand A.; Lambin, Philippe

    2005-05-01

    This review discusses the diffraction patterns of x-rays or electrons scattered by fibres of helical biological molecules and by carbon nanotubes (CNTs) from the unified point of view of the Fourier-Bessel transform of an atomic helix. This paper is intended for scientists who are not professional crystallographers. X-ray fibre diffraction patterns of Pauling's protein α-helix and of Crick and Pauling's protein coiled-coil are revisited. This is followed by a non-technical comparison between the historic x-ray diffraction patterns of the A and B conformations of DNA, which were crucial for the discovery of the double helix. The qualitative analysis of the diffraction images is supported by novel optical simulation experiments designed to pinpoint the gross structural informational content of the patterns. The spectacular helical structure of the tobacco mosaic virus determined by Rosalind Franklin and co-workers will then be described as an early example of the great power of x-ray crystallography in determining the structure of a large biomolecular edifice. After these mostly historical and didactic case studies, this paper will consider electron diffraction and transmission electron microscopy of CNTs of great current interest, focusing particularly on recent data obtained for single-wall, double-wall and scrolled nanotubes. Several points of convergence between the interpretations of the diffraction patterns of biological helices and CNTs will be emphasized.

  17. Teaching Diffraction with Hands-On Optical Spectrometry

    ERIC Educational Resources Information Center

    Fischer, Robert

    2012-01-01

    Although the observation of optical spectra is common practice in physics classes, students are usually limited to a passive, qualitative observation of nice colours. This paper discusses a diffraction-based spectrometer that allows students to take quantitative measurements of spectral bands. Students can build it within minutes from generic…

  18. Six Classes of Diffraction-Based Optoelectronic Instruments

    NASA Technical Reports Server (NTRS)

    Spremo, Stevan; Fuhr, Peter; Schipper, John

    2003-01-01

    Six classes of diffraction-based optoelectronic instruments have been invented as means for wavelength-based processing of light. One family of anticipated applications lies in scientific instrumentation for studying chemical and physical reactions that affect and/or are affected differently by light of different wavelengths or different combinations of wavelengths. Another family of anticipated applications lies in optoelectronic communication systems.

  19. Optical Simulation of Debye-Scherrer Crystal Diffraction

    ERIC Educational Resources Information Center

    Logiurato, F.; Gratton, L. M.; Oss, S.

    2008-01-01

    In this paper we describe and discuss simple, inexpensive optical experiments used to simulate x-ray and electron diffraction according to the Debye-Scherrer theory. The experiment can be used to address, at the high school level, important subjects related to fundamental quantum and solid-state physics.

  20. Rings Around the Sun and Moon: Coronae and Diffraction

    ERIC Educational Resources Information Center

    Cowley, Les; Laven, Philip; Vollmer, Michael

    2005-01-01

    Atmospheric optical effects can teach much about physics and especially optics. Coronae--coloured rings around the sun or moon--are large-scale consequences of diffraction, which is often thought of as only a small effect confined to the laboratory. We describe coronae, how they are formed and experiments that can be conducted on ones in the sky.…

  1. Fresnel Diffraction for CTR Microbunching

    SciTech Connect

    Tikhoplav, R.; Knyazik, A.; Rosenzweig, J. B.; Andonian, G.

    2009-01-22

    Laser beams of high intensities are routinely used for IFEL experiments. Such beams can potentially destroy microbunching diagnostic tools such as coherent transition radiation foils due to their low damage thresholds. Near-field Fresnel diffraction scheme for termination of CO{sub 2} laser beam has been experimentally studied and is presented in this paper. Novel THz camera was utilized for such study.

  2. The Effect of Early Teaching and Training Experience on Physics Achievement, Attitude Toward Science and Science Teaching, and Process Skill Proficiency

    ERIC Educational Resources Information Center

    Gabel, Dorothy L.; And Others

    1977-01-01

    A factorial design which intersected process skill instruction with field experience was utilized. Significantly higher physics achievement scores and process skill competency were observed for the field-experience, process-supplemented physics course. (CP)

  3. Digital diffractive optics: Have diffractive optics entered mainstream industry yet?

    NASA Astrophysics Data System (ADS)

    Kress, Bernard; Hejmadi, Vic

    2010-05-01

    When a new technology is integrated into industry commodity products and consumer electronic devices, and sold worldwide in retail stores, it is usually understood that this technology has then entered the realm of mainstream technology and therefore mainstream industry. Such a leap however does not come cheap, as it has a double edge sword effect: first it becomes democratized and thus massively developed by numerous companies for various applications, but also it becomes a commodity, and thus gets under tremendous pressure to cut down its production and integration costs while not sacrificing to performance. We will show, based on numerous examples extracted from recent industry history, that the field of Diffractive Optics is about to undergo such a major transformation. Such a move has many impacts on all facets of digital diffractive optics technology, from the optical design houses to the micro-optics foundries (for both mastering and volume replication), to the final product integrators or contract manufacturers. The main causes of such a transformation are, as they have been for many other technologies in industry, successive technological bubbles which have carried and lifted up diffractive optics technology within the last decades. These various technological bubbles have been triggered either by real industry needs or by virtual investment hype. Both of these causes will be discussed in the paper. The adjective ""digital"" in "digital diffractive optics" does not refer only, as it is done in digital electronics, to the digital functionality of the element (digital signal processing), but rather to the digital way they are designed (by a digital computer) and fabricated (as wafer level optics using digital masking techniques). However, we can still trace a very strong similarity between the emergence of micro-electronics from analog electronics half a century ago, and the emergence of digital optics from conventional optics today.

  4. Growing Larger Crystals for Neutron Diffraction

    NASA Technical Reports Server (NTRS)

    Pusey, Marc

    2003-01-01

    Obtaining crystals of suitable size and high quality has been a major bottleneck in macromolecular crystallography. With the advent of advanced X-ray sources and methods the question of size has rapidly dwindled, almost to the point where if one can see the crystal then it was big enough. Quality is another issue, and major national and commercial efforts were established to take advantage of the microgravity environment in an effort to obtain higher quality crystals. Studies of the macromolecule crystallization process were carried out in many labs in an effort to understand what affected the resultant crystal quality on Earth, and how microgravity improved the process. While technological improvements are resulting in a diminishing of the minimum crystal size required, neutron diffraction structural studies still require considerably larger crystals, by several orders of magnitude, than X-ray studies. From a crystal growth physics perspective there is no reason why these 'large' crystals cannot be obtained: the question is generally more one of supply than limitations mechanism. This talk will discuss our laboratory s current model for macromolecule crystal growth, with highlights pertaining to the growth of crystals suitable for neutron diffraction studies.

  5. Single-electron pulses for ultrafast diffraction

    PubMed Central

    Aidelsburger, M.; Kirchner, F. O.; Krausz, F.; Baum, P.

    2010-01-01

    Visualization of atomic-scale structural motion by ultrafast electron diffraction and microscopy requires electron packets of shortest duration and highest coherence. We report on the generation and application of single-electron pulses for this purpose. Photoelectric emission from metal surfaces is studied with tunable ultraviolet pulses in the femtosecond regime. The bandwidth, efficiency, coherence, and electron pulse duration are investigated in dependence on excitation wavelength, intensity, and laser bandwidth. At photon energies close to the cathode’s work function, the electron pulse duration shortens significantly and approaches a threshold that is determined by interplay of the optical pulse width and the acceleration field. An optimized choice of laser wavelength and bandwidth results in sub-100-fs electron pulses. We demonstrate single-electron diffraction from polycrystalline diamond films and reveal the favorable influences of matched photon energies on the coherence volume of single-electron wave packets. We discuss the consequences of our findings for the physics of the photoelectric effect and for applications of single-electron pulses in ultrafast 4D imaging of structural dynamics. PMID:21041681

  6. X-Ray-Diffraction Tests Of Irradiated Electronic Devices: I

    NASA Technical Reports Server (NTRS)

    Shaw, David C.; Lowry, Lynn E.; Barnes, Charles E.

    1993-01-01

    X-ray-diffraction tests performed on aluminum conductors in commercial HI1-507A complementary metal oxide/semiconductor (CMOS) integrated-circuit analog multiplexers, both before and after circuits exposed to ionizing radiation from Co(60) source, and after postirradiation annealing at ambient and elevated temperatures. Tests in addition to electrical tests performed to determine effects of irradiation and of postirradiation annealing on electrical operating characteristics of circuits. Investigators sought to determine whether relationship between effects of irradiation on devices and physical stresses within devices. X-ray diffraction potentially useful for nondestructive measurement of stresses.

  7. New approaches to nonlinear diffractive field propagation.

    PubMed

    Christopher, P T; Parker, K J

    1991-07-01

    In many domains of acoustic field propagation, such as medical ultrasound imaging, lithotripsy shock treatment, and underwater sonar, a realistic calculation of beam patterns requires treatment of the effects of diffraction from finite sources. Also, the mechanisms of loss and nonlinear effects within the medium are typically nonnegligible. The combination of diffraction, attenuation, and nonlinear effects has been treated by a number of formulations and numerical techniques. A novel model that incrementally propagates the field of baffled planar sources with substeps that account for the physics of diffraction, attenuation, and nonlinearity is presented. The model accounts for the effect of refraction and reflection (but not multiple reflections) in the case of propagation through multiple, parallel layers of fluid medium. An implementation of the model for axis symmetric sources has been developed. In one substep of the implementation, a new discrete Hankel transform is used with spatial transform techniques to propagate the field over a short distance with diffraction and attenuation. In the other substep, the temporal frequency domain solution to Burgers' equation is implemented to account for the nonlinear accretion and depletion of harmonics. This approach yields a computationally efficient procedure for calculating beam patterns from a baffled planar, axially symmetric source under conditions ranging from quasilinear through shock. The model is not restricted by the usual parabolic wave approximation and the field's directionality is explicitly accounted for at each point. Useage of a harmonic-limiting scheme allows the model to propagate some previously intractable high-intensity nonlinear fields. Results of the model are shown to be in excellent agreement with measurements performed on the nonlinear field of an unfocused 2.25-MHz piston source, even in the near field where the established parabolic wave approximation model fails. Next, the model is used to

  8. dxtbx: the diffraction experiment toolbox.

    PubMed

    Parkhurst, James M; Brewster, Aaron S; Fuentes-Montero, Luis; Waterman, David G; Hattne, Johan; Ashton, Alun W; Echols, Nathaniel; Evans, Gwyndaf; Sauter, Nicholas K; Winter, Graeme

    2014-08-01

    Data formats for recording X-ray diffraction data continue to evolve rapidly to accommodate new detector technologies developed in response to more intense light sources. Processing the data from single-crystal X-ray diffraction experiments therefore requires the ability to read, and correctly interpret, image data and metadata from a variety of instruments employing different experimental representations. Tools that have previously been developed to address this problem have been limited either by a lack of extensibility or by inconsistent treatment of image metadata. The dxtbx software package provides a consistent interface to both image data and experimental models, while supporting a completely generic user-extensible approach to reading the data files. The library is written in a mixture of C++ and Python and is distributed as part of the cctbx under an open-source licence at http://cctbx.sourceforge.net. PMID:25242914

  9. Diffraction Analysis of Solar Coronagraphs

    NASA Astrophysics Data System (ADS)

    Rabin, Douglas M.; gong, qian

    2016-05-01

    The design of a solar coronagraph is predicated on controlling diffracted and scattered light using principles dating back to Bernard Lyot in the 1930’s. The existence of many successful ground- and space-based coronagraphs testifies to our ability to apply these principles in specific cases, but it is difficult to explore a significant range of design parameters because the calculations are tricky and time-consuming. Indeed, scattered light is so design-specific that ad hoc analysis is unavoidable once guidelines from experience are used to create a first-guess system of baffles and low-scatter surfaces. Here we describe a combination of analytic and computational approaches that has the potential to explore coronagraph design space somewhat more systematically with respect to diffracted light.

  10. Diffraction operators in paraxial approach

    NASA Astrophysics Data System (ADS)

    Lasso, William; Navas, Marianela; Añez, Liz; Urdaneta, Romer; Díaz, Leonardo; Torres, César O.

    2014-07-01

    Nowadays, research in the field of science education points to the creation of alternative ways of teaching contents encouraging the development of more elaborate reasoning, where a high degree of abstraction and generalization of scientific knowledge prevails. On that subject, this research shows a didactic alternative proposal for the construction of Fresnel and Fraunhoffer diffraction concepts applying the Fourier transform technique in the study of electromagnetic waves propagation in free space. Curvature transparency and Fourier sphere operators in paraxial approximation are used in order to make the usual laborious mathematical approach easier. The main result shows that the composition of optic metaxial operators results in the discovery of a simpler way out of the standard electromagnetic wave propagation in free space between a transmitter and a receptor separated from a given distance. This allows to state that the didactic proposal shown encourages the construction of Fresnel and Fraunhoffer diffraction concepts in a more effective and easier way than the traditional teaching.

  11. Diffraction gratings for lighting applications

    NASA Astrophysics Data System (ADS)

    Cornelissen, Hugo J.; de Boer, Dick K. G.; Tukker, Teus

    2013-09-01

    Sub-micron diffraction gratings have been used for two LED illumination applications. One is to create a transparent see through luminaire which can be used to illuminate and read a paper document or e-book. A second is a light sensor that can be used in a feedback loop to control a multicolor LED lamp. Optical design and experimental proof-of-principle are presented.

  12. Diffraction techniques in structural biology.

    PubMed

    Egli, Martin

    2010-06-01

    A detailed understanding of chemical and biological function and the mechanisms underlying the molecular activities ultimately requires atomic-resolution structural data. Diffraction-based techniques such as single-crystal X-ray crystallography, electron microscopy, and neutron diffraction are well established and they have paved the road to the stunning successes of modern-day structural biology. The major advances achieved in the last 20 years in all aspects of structural research, including sample preparation, crystallization, the construction of synchrotron and spallation sources, phasing approaches, and high-speed computing and visualization, now provide specialists and nonspecialists alike with a steady flow of molecular images of unprecedented detail. The present unit combines a general overview of diffraction methods with a detailed description of the process of a single-crystal X-ray structure determination experiment, from chemical synthesis or expression to phasing and refinement, analysis, and quality control. For novices it may serve as a stepping-stone to more in-depth treatises of the individual topics. Readers relying on structural information for interpreting functional data may find it a useful consumer guide. PMID:20517991

  13. Diffraction Techniques in Structural Biology.

    PubMed

    Egli, Martin

    2016-01-01

    A detailed understanding of chemical and biological function and the mechanisms underlying the molecular activities ultimately requires atomic-resolution structural data. Diffraction-based techniques such as single-crystal X-ray crystallography, electron microscopy, and neutron diffraction are well established and they have paved the road to the stunning successes of modern-day structural biology. The major advances achieved in the last twenty years in all aspects of structural research, including sample preparation, crystallization, the construction of synchrotron and spallation sources, phasing approaches, and high-speed computing and visualization, now provide specialists and nonspecialists alike with a steady flow of molecular images of unprecedented detail. The present unit combines a general overview of diffraction methods with a detailed description of the process of a single-crystal X-ray structure determination experiment, from chemical synthesis or expression to phasing and refinement, analysis, and quality control. For novices it may serve as a stepping-stone to more in-depth treatises of the individual topics. Readers relying on structural information for interpreting functional data may find it a useful consumer guide. © 2016 by John Wiley & Sons, Inc. PMID:27248784

  14. Vorticity production in shock diffraction

    NASA Astrophysics Data System (ADS)

    Sun, M.; Takayama, K.

    2003-03-01

    The production of vorticity or circulation production in shock wave diffraction over sharp convex corners has been numerically simulated and quantified. The corner angle is varied from 5° to 180°. Total vorticity is represented by the circulation, which is evaluated by integrating the velocity along a path enclosing the perturbed region behind a diffracting shock wave. The increase of circulation in unit time, or the rate of circulation production, depends on the shock strength and wall angle if the effects of viscosity and heat conductivity are neglected. The rate of vorticity production is determined by using a solution-adaptive code, which solves the Euler equations. It is shown that the rate of vorticity production is independent of the computational mesh and numerical scheme by comparing solutions from two different codes. It is found that larger wall angles always enhance the vorticity production. The vorticity production increases sharply when the corner angle is varied from 15° to 45°. However, for corner angles over 90°, the rate of vorticity production hardly increases and reaches to a constant value. Strong shock waves produce vorticity faster in general, except when the slipstream originating from the shallow corner attaches to the downstream wall. It is found that the vorticity produced by the slipstream represents a large proportion of the total vorticity. The slipstream is therefore a more important source of vorticity than baroclinic effects in shock diffraction.

  15. Liquid crystal filled diffraction gratings

    NASA Astrophysics Data System (ADS)

    Jepsen, Mary Lou

    1997-12-01

    Liquid crystal technology is becoming increasingly important for flat displays in electronics, computers and TV. Most liquid crystal displays currently made have as their basic unit, two flat surfaces each coated with a transparent, conductive layer, between which a thin layer of liquid crystals is sandwiched. The work detailed in this dissertation is based on a modification of the basic liquid crystal unit and studies the properties of structures which consist of certain anisotropic liquid crystals confined between a flat substrate and a corrugated one, each substrate being transparent and having a thin trans-parent conductive coating. Without an applied electric field, the refractive indices of the liquid crystal and corrugated substrate do not match, and thus strong diffraction occurs. When an electric field is applied to the device, the liquid crystals are re-oriented so that the refractive indices now match, and the device behaves as a uniform slab of homogeneous material producing no diffraction. Rigorous coupled wave analysis was developed to design the ideal devices and analyze the performance of our experimental ones. 99% diffraction efficiencies in single wavelength polarized illumination are shown to be possible with this class of devices. The best device we fabricated showed a 62% distraction efficiency, as our fabrication process roughened the top surface of the device so that (≃30%) of the incident light was lost to scatter. Several new fabrication processes are proposed to eliminate this scatter problem, and that details of fabrication processes thus far attempted are outlined.

  16. Stretchable diffraction gratings for spectrometry

    NASA Astrophysics Data System (ADS)

    Simonov, Aleksey N.; Grabarnik, Semen; Vdovin, Gleb

    2007-07-01

    We have investigated the possibility of using transparent stretchable diffraction gratings for spectrometric applications. The gratings were fabricated by replication of a triangular-groove master into a transparent viscoelastic. The sample length, and hence the spatial period, can be reversibly changed by mechanical stretching. When used in a monochromator with two slits, the stretchable grating permits scanning the spectral components over the output slit, converting the monochromator into a scanning spectrometer. The spectral resolution of such a spectrometer was found to be limited mainly by the wave-front aberrations due to the grating deformation. A model relating the deformation-induced aberrations in different diffraction orders is presented. In the experiments, a 12-mm long viscoelastic grating with a spatial frequency of 600 line pairs/mm provided a full-width at half-maximum resolution of up to ~1.2 nm in the 580-680 nm spectral range when slowly stretched by a micrometer screw and ~3 nm when repeatedly stretched by a voice coil at 15 Hz. Comparison of aberrations in transmitted and diffracted beams measured by a Shack- Hartmann wave-front sensor showed that astigmatisms caused by stretch-dependent wedge deformation are the main factors limiting the resolution of the viscoelastic-grating-based spectrometer.

  17. Diffraction Techniques in Structural Biology

    PubMed Central

    Egli, Martin

    2010-01-01

    A detailed understanding of chemical and biological function and the mechanisms underlying the activities ultimately requires atomic-resolution structural data. Diffraction-based techniques such as single-crystal X-ray crystallography, electron microscopy and neutron diffraction are well established and have paved the road to the stunning successes of modern-day structural biology. The major advances achieved in the last 20 years in all aspects of structural research, including sample preparation, crystallization, the construction of synchrotron and spallation sources, phasing approaches and high-speed computing and visualization, now provide specialists and non-specialists alike with a steady flow of molecular images of unprecedented detail. The present chapter combines a general overview of diffraction methods with a step-by-step description of the process of a single-crystal X-ray structure determination experiment, from chemical synthesis or expression to phasing and refinement, analysis and quality control. For novices it may serve as a stepping-stone to more in-depth treatises of the individual topics. Readers relying on structural information for interpreting functional data may find it a useful consumer guide. PMID:20517991

  18. Monitoring model drug microencapsulation in PLGA scaffolds using X-ray powder diffraction

    PubMed Central

    Aina, Adeyinka; Gupta, Manish; Boukari, Yamina; Morris, Andrew; Billa, Nashiru; Doughty, Stephen

    2015-01-01

    The microencapsulation of three model drugs; metronidazole, paracetamol and sulphapyridine into Poly (dl-Lactide-Co-Glycolide) (PLGA) scaffolds were probed using X-ray Powder Diffraction (XRPD). Changes in the diffraction patterns of the PLGA scaffolds after encapsulation was suggestive of a chemical interaction between the pure drugs and the scaffolds and not a physical intermixture. PMID:27013917

  19. Integral representation of the edge diffracted waves along the ray path of the transition region.

    PubMed

    Umul, Yusuf Z

    2008-09-01

    The expression of the edge diffracted fields, in terms of the Fresnel integral, is transformed into a path integral. The obtained integral considers the integration of the incident field along the ray path of the transition region. The similarities of the path integral with Kirchhoff's theory of diffraction and the modified theory of physical optics are examined. PMID:18758538

  20. Adaptability of laser diffraction measurement technique in soil physics methodology

    NASA Astrophysics Data System (ADS)

    Barna, Gyöngyi; Szabó, József; Rajkai, Kálmán; Bakacsi, Zsófia; Koós, Sándor; László, Péter; Hauk, Gabriella; Makó, András

    2016-04-01

    There are intentions all around the world to harmonize soils' particle size distribution (PSD) data by the laser diffractometer measurements (LDM) to that of the sedimentation techniques (pipette or hydrometer methods). Unfortunately, up to the applied methodology (e. g. type of pre-treatments, kind of dispersant etc.), PSDs of the sedimentation methods (due to different standards) are dissimilar and could be hardly harmonized with each other, as well. A need was arisen therefore to build up a database, containing PSD values measured by the pipette method according to the Hungarian standard (MSZ-08. 0205: 1978) and the LDM according to a widespread and widely used procedure. In our current publication the first results of statistical analysis of the new and growing PSD database are presented: 204 soil samples measured with pipette method and LDM (Malvern Mastersizer 2000, HydroG dispersion unit) were compared. Applying usual size limits at the LDM, clay fraction was highly under- and silt fraction was overestimated compared to the pipette method. Subsequently soil texture classes determined from the LDM measurements significantly differ from results of the pipette method. According to previous surveys and relating to each other the two dataset to optimizing, the clay/silt boundary at LDM was changed. Comparing the results of PSDs by pipette method to that of the LDM, in case of clay and silt fractions the modified size limits gave higher similarities. Extension of upper size limit of clay fraction from 0.002 to 0.0066 mm, and so change the lower size limit of silt fractions causes more easy comparability of pipette method and LDM. Higher correlations were found between clay content and water vapor adsorption, specific surface area in case of modified limit, as well. Texture classes were also found less dissimilar. The difference between the results of the two kind of PSD measurement methods could be further reduced knowing other routinely analyzed soil parameters (e.g. pH(H2O), organic carbon and calcium carbonate content).

  1. Point source diffraction by a slit in a moving fluid

    NASA Astrophysics Data System (ADS)

    Nawaz, Rab; Naeem, Amjad; Ayub, Muhammad; Javaid, Akmal

    2014-10-01

    The diffraction of a spherical acoustic wave generated by a point source from impedance slit in a moving fluid is investigated. The diffracted wave is calculated in the far field regime as a sum of fields produced by the edges of the slit and an incident field. The Myers' impedance conditions are assumed along the edges of the slit. Such conditions are well adopted for the boundaries of the impedance barriers and yield reliable predictions of the diffraction patterns. A Wiener-Hopf technique is invoked to resolve the problem in combination with Fourier transform techniques and asymptotic analysis. The appositeness of the results and the effect of pertinent physical parameters on the separated field are presented and analyzed graphically.

  2. The Impact of Physical Maltreatment History on the Adolescent Mother-Infant Relationship: Mediating and Moderating Effects during the Transition to Early Parenthood

    ERIC Educational Resources Information Center

    Milan, Stephanie; Lewis, Jessica; Ethier, Kathleen; Kershaw, Trace; Ickovics, Jeannette R.

    2004-01-01

    Using attachment theory as a framework, this paper examines how pregnant adolescents' experiences of physical maltreatment during childhood influence the subsequent mother-infant relationship in 203 low-income adolescents followed from the 3rd trimester of pregnancy through the 1st year of parenthood. The relation between physical maltreatment…

  3. 50 years of fiber diffraction.

    PubMed

    Holmes, Kenneth C

    2010-05-01

    In 1955 Ken Holmes started working on tobacco mosaic virus (TMV) as a research student with Rosalind Franklin at Birkbeck College, London. Afterward he spent 18months as a post doc with Don Caspar and Carolyn Cohen at the Children's Hospital, Boston where he continued the work on TMV and also showed that the core of the thick filament of byssus retractor muscle from mussels is made of two-stranded alpha-helical coiled-coils. Returning to England he joined Aaron Klug's group at the newly founded Laboratory of Molecular Biology in Cambridge. Besides continuing the TMV studies, which were aimed at calculating the three-dimensional density map of the virus, he collaborated with Pringle's group in Oxford to show that two conformation of the myosin cross-bridge could be identified in insect flight muscle. In 1968 he opened the biophysics department at the Max Planck Institute for Medical Research in Heidelberg, Germany. With Gerd Rosenbaum he initiated the use of synchrotron radiation as a source for X-ray diffraction. In his lab the TMV structure was pushed to 4A resolution and showed how the RNA binds to the protein. With his co-workers he solved the structure of g-actin as a crystalline complex and then solved the structure of the f-actin filament by orientating the g-actin structure so as to give the f-actin fiber diffraction pattern. He was also able to solve the structure of the complex of actin with tropomyosin from fiber diffraction. PMID:20079849

  4. Coherent Diffractive Imaging at LCLS

    NASA Astrophysics Data System (ADS)

    Schulz, Joachim

    2010-03-01

    Soft x-ray FEL light sources produce ultrafast x-ray pulses with outstanding high peak brilliance. This might enable the structure determination of proteins that cannot be crystallized. The deposited energy would destroy the molecules completely, but owing to the short pulses the destruction will ideally only happen after the termination of the pulse. In order to address the many challenges that we face in attempting molecular diffraction, we have carried out experiments in coherent diffraction from protein nanocrystals at the Linac Coherent Light Source (LCLS) at SLAC. The periodicity of these objects gives us much higher scattering signals than uncrystallized proteins would. The crystals are filtered to sizes less than 2 micron, and delivered to the pulsed X-ray beam in a liquid jet. The effects of pulse duration and fluence on the high-resolution structure of the crystals have been studied. Diffraction patterns are recorded at a repetition rate of 30 Hz with pnCCD detectors. This allows us to take 108,000 images per hour. With 2-mega-pixel-detectors this gives a data-rate of more than 400 GB per hour. The automated sorting and evaluation of hundreds of thousands images is another challenge of this kind of experiments. Preliminary results will be presented on our first LCLS experiments. This work was carried out as part of a collaboration, for which Henry Chapman is the spokesperson. The collaboration consists of CFEL DESY, Arizona State University, SLAC, Uppsala University, LLNL, The University of Melbourne, LBNL, the Max Planck Institute for Medical Research, and the Max Planck Advanced Study Group (ASG) at the CFEL. The experiments were carried out using the CAMP apparatus, which was designed and built by the Max Planck ASG at CFEL. The LCLS is operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences.

  5. Crystallography: Resolution beyond the diffraction limit

    NASA Astrophysics Data System (ADS)

    Shen, Jian-Ren

    2016-02-01

    A method has been devised that extends the resolution of X-ray crystal structures beyond the diffraction limit. This might help to improve the visualization of structures of proteins that form 'poorly diffracting' crystals. See Letter p.202

  6. Fiber optic diffraction grating maker

    DOEpatents

    Deason, Vance A.; Ward, Michael B.

    1991-01-01

    A compact and portable diffraction grating maker comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent beam splitters, and collimating lenses or mirrors directing the split beam at an appropriate photosensitive material. The collimating optics, the output ends of the fiber optic coupler and the photosensitive plate holder are all mounted on an articulated framework so that the angle of intersection of the beams can be altered at will without disturbing the spatial filter, collimation or beam quality, and assuring that the beams will always intersect at the position of the plate.

  7. Fiber optic diffraction grating maker

    DOEpatents

    Deason, V.A.; Ward, M.B.

    1991-05-21

    A compact and portable diffraction grating maker is comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent beam splitters, and collimating lenses or mirrors directing the split beam at an appropriate photosensitive material. The collimating optics, the output ends of the fiber optic coupler and the photosensitive plate holder are all mounted on an articulated framework so that the angle of intersection of the beams can be altered at will without disturbing the spatial filter, collimation or beam quality, and assuring that the beams will always intersect at the position of the plate. 4 figures.

  8. Nonlinear ptychographic coherent diffractive imaging.

    PubMed

    Odstrcil, M; Baksh, P; Gawith, C; Vrcelj, R; Frey, J G; Brocklesby, W S

    2016-09-01

    Ptychographic Coherent diffractive imaging (PCDI) is a significant advance in imaging allowing the measurement of the full electric field at a sample without use of any imaging optics. So far it has been confined solely to imaging of linear optical responses. In this paper we show that because of the coherence-preserving nature of nonlinear optical interactions, PCDI can be generalised to nonlinear optical imaging. We demonstrate second harmonic generation PCDI, directly revealing phase information about the nonlinear coefficients, and showing the general applicability of PCDI to nonlinear interactions. PMID:27607631

  9. Issues in Optical Diffraction Theory

    PubMed Central

    Mielenz, Klaus D.

    2009-01-01

    This paper focuses on unresolved or poorly documented issues pertaining to Fresnel’s scalar diffraction theory and its modifications. In Sec. 2 it is pointed out that all thermal sources used in practice are finite in size and errors can result from insufficient coherence of the optical field. A quarter-wave criterion is applied to show how such errors can be avoided by placing the source at a large distance from the aperture plane, and it is found that in many cases it may be necessary to use collimated light as on the source side of a Fraunhofer experiment. If these precautions are not taken the theory of partial coherence may have to be used for the computations. In Sec. 3 it is recalled that for near-zone computations the Kirchhoff or Rayleigh-Sommerfeld integrals are applicable, but fail to correctly describe the energy flux across the aperture plane because they are not continuously differentiable with respect to the assumed geometrical field on the source side. This is remedied by formulating an improved theory in which the field on either side of a semi-reflecting screen is expressed as the superposition of mutually incoherent components which propagate in the opposite directions of the incident and reflected light. These components are defined as linear combinations of the Rayleigh-Sommerfeld integrals, so that they are rigorous solutions of the wave equation as well as continuously differentiable in the aperture plane. Algorithms for using the new theory for computing the diffraction patterns of circular apertures and slits at arbitrary distances z from either side of the aperture (down to z = ± 0.0003 λ) are presented, and numerical examples of the results are given. These results show that the incident geometrical field is modulated by diffraction before it reaches the aperture plane while the reflected field is spilled into the dark space. At distances from the aperture which are large compared to the wavelength λ these field expressions are

  10. Twenty Meter Space Telescope Based on Diffractive Fresnel Lens

    SciTech Connect

    Early, J; Hyde, R; Baron, R

    2003-06-26

    Diffractive lenses offer two potential advantages for very large aperture space telescopes; very loose surface-figure tolerances and physical implementation as thin, flat optical elements. In order to actually realize these advantages one must be able to build large diffractive lenses with adequate optical precision and also to compactly stow the lens for launch and then fully deploy it in space. We will discuss the recent fabrication and assembly demonstration of a 5m glass diffractive Fresnel lens at LLNL. Optical performance data from smaller full telescopes with diffractive lens and corrective optics show diffraction limited performance with broad bandwidths. A systems design for a 20m space telescope will be presented. The primary optic can be rolled to fit inside of the standard fairings of the Delta IV vehicle. This configuration has a simple deployment and requires no orbital assembly. A twenty meter visible telescope could have a significant impact in conventional astronomy with eight times the resolution of Hubble and over sixty times the light gathering capacity. If the light scattering is made acceptable, this telescope could also be used in the search for terrestrial planets.

  11. Diffraction Gratings for High-Intensity Laser Applications

    SciTech Connect

    Britten, J

    2008-01-23

    The scattering of light into wavelength-dependent discrete directions (orders) by a device exhibiting a periodic modulation of a physical attribute on a spatial scale similar to the wavelength of light has been the subject of study for over 200 years. Such a device is called a diffraction grating. Practical applications of diffraction gratings, mainly for spectroscopy, have been around for over 100 years. The importance of diffraction gratings in spectroscopy for the measurement of myriad properties of matter can hardly be overestimated. Since the advent of coherent light sources (lasers) in the 1960's, applications of diffraction gratings in spectroscopy have further exploded. Lasers have opened a vast application space for gratings, and apace, gratings have enabled entirely new classes of laser systems. Excellent reviews of the history, fundamental properties, applications and manufacturing techniques of diffraction gratings up to the time of their publication can be found in the books by Hutley (1) and more recently Loewen and Popov (2). The limited scope of this chapter can hardly do justice to such a comprehensive subject, so the focus here will be narrowly limited to characteristics required for gratings suitable for high-power laser applications, and methods to fabricate them. A particular area of emphasis will be on maximally-efficient large-aperture gratings for short-pulse laser generation.

  12. Diffraction-controlled backscattering threshold and application to Raman gap

    SciTech Connect

    Rose, Harvey A.; Mounaix, Philippe

    2011-04-15

    In most classic analytical models of linear stimulated scatter, light diffraction is omitted, a priori. However, modern laser optic typically includes a variant of the random phase plate [Y. Kato et al., Phys. Rev. Lett. 53, 1057 (1984)], resulting in diffraction limited laser intensity fluctuations - or localized speckles - which may result in explosive reflectivity growth as the average laser intensity approaches a critical value [H. A. Rose and D. F. DuBois, Phys. Rev. Lett. 72, 2883 (1994)]. Among the differences between stimulated Raman scatter (SRS) and stimulated Brillouin scatter is that the SRS scattered light diffracts more strongly than the laser light with increase of electron density. This weakens the tendency of the SRS light to closely follow the most amplified paths, diminishing gain. Let G{sub 0} be the one-dimensional power gain exponent of the stimulated scatter. In this paper we show that differential diffraction gives rise to an increase of G{sub 0} at the SRS physical threshold with increase of electron density up to a drastic disruption of SRS as electron density approaches one fourth of its critical value from below. For three wave interaction lengths not small compared to a speckle length, this is a physically robust Raman gap mechanism.

  13. Obesity, Physical Activity - Children.

    ERIC Educational Resources Information Center

    Gilliam, Thomas B.

    Childhood obesity starts at a very early age, and preventive measures taken early enough may retard the development of fat cells. It appears that physical activity plays an important role in reducing obesity. The activity program must start early, in preschool days. It is felt that screening children for obesity when they first enter school and…

  14. Ultrafast electron diffraction from aligned molecules

    SciTech Connect

    Centurion, Martin

    2015-08-17

    The aim of this project was to record time-resolved electron diffraction patterns of aligned molecules and to reconstruct the 3D molecular structure. The molecules are aligned non-adiabatically using a femtosecond laser pulse. A femtosecond electron pulse then records a diffraction pattern while the molecules are aligned. The diffraction patterns are then be processed to obtain the molecular structure.

  15. Undergraduate Experiment with Fractal Diffraction Gratings

    ERIC Educational Resources Information Center

    Monsoriu, Juan A.; Furlan, Walter D.; Pons, Amparo; Barreiro, Juan C.; Gimenez, Marcos H.

    2011-01-01

    We present a simple diffraction experiment with fractal gratings based on the triadic Cantor set. Diffraction by fractals is proposed as a motivating strategy for students of optics in the potential applications of optical processing. Fraunhofer diffraction patterns are obtained using standard equipment present in most undergraduate physics…

  16. Diffraction optics for terahertz waves

    NASA Astrophysics Data System (ADS)

    Wiltse, James C.

    2004-09-01

    Conventional lenses are important components for many terahertz applications, but ordinary lenses are very difficult to fabricate for short-focal lengths. Multi-level phase-corrected zoned lens antennas have been investigated with particular application at terahertz wavelengths. These zoned lenses (or diffractive optics) give better performance than ordinary lenses, and because of their planar construction are easier and cheaper to fabricate. The depths of cut needed for a grooved zone plate are quite small, even when materials with low dielectric constants are used. Zoned lenses have been built and tested at various frequencies from 100 GHz to 1.5 THz, with phase correction levels of half-wave, quarter-wave, or eighth-wavelength. The inherent losses in transparent materials increase monotonically over this frequency range. Typical low-loss materials include polystyrene, polyethylene, Teflon, polycarbonate, polystyrene foam, foamed polyethylene, low density polytetrafluoroethylene (PTFE), TPX, quartz, sapphire, and silicon. Low dielectric-constant materials are normally preferred to reduce reflection and attenuation losses. Techniques for cutting or milling the materials to small dimensions are important, because at 1.0 THz an eighth-wavelength correction for silicon is only 15 μm. Another characteristic of zoned diffraction optics is their frequency behavior. Previous investigations have considered their bandwidth dependence and quasi-periodic extended frequency response for a specified focal length. As frequency changes, the focal point moves along the axis of the zoned lens. An analysis is given to explain this effect.

  17. Transient x-ray diffraction and its application to materials science and x-ray optics

    SciTech Connect

    Hauer, A.A.; Kopp, R.; Cobble, J.; Kyrala, G.; Springer, R.

    1997-12-01

    Time resolved x-ray diffraction and scattering have been applied to the measurement of a wide variety of physical phenomena from chemical reactions to shock wave physics. Interest in this method has heightened in recent years with the advent of versatile, high power, pulsed x-ray sources utilizing laser plasmas, electron beams and other methods. In this article, we will describe some of the fundamentals involved in time resolved x-ray diffraction, review some of the history of its development, and describe some recent progress in the field. In this article we will emphasize the use of laser-plasmas as the x-ray source for transient diffraction.

  18. Spatial structure of a focused X-ray beam diffracted from crystals

    PubMed Central

    Kazimirov, A.; Kohn, V. G.; Snigirev, A.; Snigireva, I.

    2009-01-01

    The spatial structure of a beam focused by a planar refractive lens and Bragg diffracted from perfect silicon crystals was experimentally studied at the focal plane using a knife-edge scan and a high-resolution CCD camera. The use of refractive lenses allowed for a detailed comparison with theory. It was shown that diffraction leads to broadening of the focused beam owing to the extinction effect and, for a sufficiently thin crystal, to the appearance of a second peak owing to reflection from the back surface. It was found that the spatial structure of the diffracted beam depends on whether the crystal diffracts strongly (dynamically) or weakly (kinematically). The results help to understand the physical origin of the diffracted intensity recorded in a typical microbeam diffraction experiment. PMID:19713641

  19. Active learning in optics and photonics: Fraunhofer diffraction

    NASA Astrophysics Data System (ADS)

    Ghalila, H.; Ben Lakhdar, Z.; Lahmar, S.; Dhouaidi, Z.; Majdi, Y.

    2014-07-01

    "Active Learning in Optics and Photonics" (ALOP), funded by UNESCO within its Physics Program framework with the support of ICTP (Abdus Salam International Centre for Theoretical Physics) and SPIE (Society of Photo-Optical Instrumentation Engineers), aimed to helps and promotes a friendly and interactive method in teaching optics using simple and inexpensive equipment. Many workshops were organized since 2005 the year when Z. BenLakhdar, whom is part of the creators of ALOP, proposed this project to STO (Société Tunisienne d'Optique). These workshops address several issues in optics, covering geometrical optics, wave optics, optical communication and they are dedicated to both teachers and students. We focus this lecture on Fraunhofer diffraction emphasizing the facility to achieve this mechanism in classroom, using small laser and operating a slit in a sheet of paper. We accompany this demonstration using mobile phone and numerical modeling to assist in the analysis of the diffraction pattern figure.

  20. News and Views: New books to look out for; Prizes waiting for environmental physics essays; Meeting encourages early career scientists; A cosmological challenge

    NASA Astrophysics Data System (ADS)

    2008-12-01

    The RAS is pleased to announce the publication of the first book in its new publishing venture, the RAS Series. The UK Planetary Forum held its sixth Early Career Scientists' Meeting at University College London on 3 November 2008. 50 researchers attended, presenting and discussing their research, and making the contacts essential for future success. Katherine Joy, Vic Pearson and Caroline Smith report.

  1. Why Won't My Torch Work? Physics for 4 to 8 Year Olds. Australian Early Childhood Resource Booklets No. 1.

    ERIC Educational Resources Information Center

    Fleer, Marilyn

    Young children in Australia enter early childhood education settings eager to make sense of the world that surrounds them. Their interest in every day experiences is evident in the range of questions asked, many of which are scientific in nature. Intended as a resource for adults working with 4-to 8-year-old children, this booklet provides an…

  2. Forward Physics Results from ATLAS and CMS

    NASA Astrophysics Data System (ADS)

    Sen, Sercan

    2013-12-01

    We present recent forward and diffractive physics results from ATLAS and CMS experiments. Mainly, the physics results on diffraction, underlying event at forward rapidity and forward jets measurements are discussed. Also, using the combined CMS and TOTEM detectors, we show the first event candidate for central jets production with two leading protons detected in the TOTEM Roman Pot stations.

  3. Polarized point diffraction interferometer for fringe stabilization

    NASA Astrophysics Data System (ADS)

    Kihm, Hagyong; Lee, Yun-Woo

    2010-08-01

    We propose a new point diffraction interferometer using a polarizer with a pinholed for qualitative optical analysis. Diffraction from a polarizer with a pinholed makes reference and measurement waves. Interference fringe between diffracted-undiffracted measurement wave and undiffracted-diffracted reference wave is stabilized by common-path configuration. We examined the pinhole size and divergence angle of the diffracted wave for test optics with various numerical aperture. Optical parts comprising the interferometer can be assembled into a small monolithic component and embedded into an imaging target for easy alignment. Optical systems evaluating imaging performances such as modulation transfer function would benefit in aligning target objects.

  4. Diffraction gratings for optical sensing

    NASA Astrophysics Data System (ADS)

    Lu, Patrick P.

    The following document summarizes a journey through the world of diffraction gratings, covering topics such as their history, fabrication, metrology, and uses in some of the most precise scientific experiments ever proposed. Though diffraction gratings have long been used for spectroscopy and pulse compression, it was not until recently that researchers have explored their ability to split and recombine single-frequency CW laser sources for high-precision interferometry. Gravitational-wave detection, one of the most challenging sensing applications to date, is being investigated by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Laser Interferometer Space Antenna (LISA) projects. Future generations of LIGO and LISA detectors may incorporate gratings as key optical components. This thesis describes the ways gratings can improve interferometer performance by simplifying thermal management and discusses the essential challenges that must be overcome before they can be adopted. The use of gratings requires new interferometer geometries. We show cases where these can be implemented simply and compactly. Gravitational-wave interferometry imposes many requirements on grating components. Using improved metrology methods, we demonstrate that large dielectric gratings with uniformly high efficiency can be fabricated and validated. In particular, we measure the diffraction efficiency of two 20-cm-scale gratings over their entire apertures. The values taken from across their surfaces collectively had means and standard deviations of mu = 99.293% and sigma = 0.164%, and mu =99.084% and sigma =0.079%. We also present simplified models of thermal distortions in gratings, and show them to be in good agreement with measurements conducted by a wavefront sensor. Special focus is given to experimental demonstrations that have achieved highly precise measurements of translational and rotational motion, also known as displacement and angular sensing. For the former

  5. Training and Technical Assistance for Compliance With Beverage and Physical Activity Components of New York City’s Regulations for Early Child Care Centers

    PubMed Central

    Dunn, Lillian; O’Dell, Sarah Abood; Jernigan, Jan; Kettel Khan, Laura

    2014-01-01

    Introduction In 2006, the New York City Department of Health and Mental Hygiene (DOHMH) passed regulations for child care centers that established standards for beverages provided to children and set a minimum amount of time for daily physical activity. DOHMH offered several types of training and technical assistance to support compliance with the regulations. This article analyzes the association between training and technical assistance provided and compliance with the regulations in a sample of 174 group child care centers. Methods Compliance was measured by using a site inventory of beverages stored on premises and a survey of centers’ teachers regarding the amount of physical activity provided. Training and technical assistance measures were based on the DOHMH records of training and technical assistance provided to the centers in the sample and on a survey of center directors. Ordinal logistic regression was used to assess the association between training and technical assistance measures and compliance with the regulations. Results Measures of training related to physical activity the center received: the number of staff members who participated in Sport, Play and Active Recreation for Kids (SPARK) and other training programs in which a center participated were associated with better compliance with the physical activity regulations. Neither training nor technical assistance were associated with compliance with the regulations related to beverages. Conclusion Increased compliance with regulations pertaining to physical activity was not related to compliance with beverage regulations. Future trainings should be targeted to the specific regulation requirements to increase compliance. PMID:25321628

  6. Fresnel diffraction of aperture with rough edge

    NASA Astrophysics Data System (ADS)

    Cui, Yuwei; Zhang, Wei; Wang, Junhong; Zhang, Meina; Teng, Shuyun

    2015-06-01

    The Fresnel diffraction of an aperture with a rough edge is studied in this paper. Circular and elliptical apertures with sinusoidal and random edges are chosen as examples to investigate the influence of the aperture edge on the diffraction. The numerical calculation results indicate intuitively the variations of the transverse and longitude diffraction intensity distributions with the edge parameters of the aperture. The data files of aperture models are obtained through the numerical calculations, and the aperture samples are obtained with the help of a liquid crystal light modulator (LCLM). Thus, the practical experiments of the diffractions of apertures with rough edges are carried out. The measured results are consistent with the calculated ones. The approximate analytic expressions of the diffraction by the modified aperture are deduced on the basis of the Fresnel diffraction theory and the statistic optics, and the reasonable explanations for the influence of edge parameters on the diffraction are given through the theoretical analysis.

  7. Diffractive X-Ray Telescopes

    NASA Technical Reports Server (NTRS)

    Skinner, Gerald K.

    2010-01-01

    Diffractive X-ray telescopes, using zone plates, phase Fresnel lenses, or related optical elements have the potential to provide astronomers with true imaging capability with resolution many orders of magnitude better than available in any other waveband. Lenses that would be relatively easy to fabricate could have an angular resolution of the order of micro-arc-seconds or even better, that would allow, for example, imaging of the distorted spacetime in the immediate vicinity of the super-massive black holes in the center of active galaxies. What then is precluding their immediate adoption? Extremely long focal lengths, very limited bandwidth, and difficulty stabilizing the image are the main problems. The history, and status of the development of such lenses is reviewed here and the prospects for managing the challenges that they present are discussed.

  8. Variable focus crystal diffraction lens

    SciTech Connect

    Smither, R.K.

    1988-11-01

    A new method has been developed to control the shape of the surface of a diffracting crystal that will allow it to function as a variable focus crystal diffraction lens, for focusing photon beams from a synchrotron source. The new method uses thermal gradients in the crystal to control the shape of the surface of the crystal in two dimensions and allows one to generate both spherical and ellipsoidal surface shapes. In this work the thermal gradient was generated by core drilling two sets of cooling channels in a silicon crystal so that cooling or heating fluids could be circulated through the crystal at two different levels. The first set of channels is close to the surface of the crystal where the photon beam strikes it. The second set of channels is equal distant from the back surface. If a concave surface is desired, the fluid in the channels just below the surface exposed to the beam is cooler than the fluid circulating through the channels near the back surface. If a convex surface is desired, then the cooling fluid in the upper channels near the surface exposed to the incident photon beam, is warmer than the fluid in the lower channels. The focal length of the crystal lens is varied by varying the thermal gradient in the crystal. This approach can also be applied to the first crystal in a high power synchrotron beam line to eliminate the bowing and other thermal distortions of the crystal caused by the high heat load. 6 refs., 8 figs., 3 tabs.

  9. On effective and optical resolutions of diffraction data sets.

    PubMed

    Urzhumtseva, Ludmila; Klaholz, Bruno; Urzhumtsev, Alexandre

    2013-10-01

    In macromolecular X-ray crystallography, diffraction data sets are traditionally characterized by the highest resolution dhigh of the reflections that they contain. This measure is sensitive to individual reflections and does not refer to the eventual data incompleteness and anisotropy; it therefore does not describe the data well. A physically relevant and robust measure that provides a universal way to define the `actual' effective resolution deff of a data set is introduced. This measure is based on the accurate calculation of the minimum distance between two immobile point scatterers resolved as separate peaks in the Fourier map calculated with a given set of reflections. This measure is applicable to any data set, whether complete or incomplete. It also allows characterizion of the anisotropy of diffraction data sets in which deff strongly depends on the direction. Describing mathematical objects, the effective resolution deff characterizes the `geometry' of the set of measured reflections and is irrelevant to the diffraction intensities. At the same time, the diffraction intensities reflect the composition of the structure from physical entities: the atoms. The minimum distance for the atoms typical of a given structure is a measure that is different from and complementary to deff; it is also a characteristic that is complementary to conventional measures of the data-set quality. Following the previously introduced terms, this value is called the optical resolution, dopt. The optical resolution as defined here describes the separation of the atomic images in the `ideal' crystallographic Fourier map that would be calculated if the exact phases were known. The effective and optical resolution, as formally introduced in this work, are of general interest, giving a common `ruler' for all kinds of crystallographic diffraction data sets. PMID:24100312

  10. Future of Electron Scattering and Diffraction

    SciTech Connect

    Hall, Ernest; Stemmer, Susanne; Zheng, Haimei; Zhu, Yimei; Maracas, George

    2014-02-25

    The ability to correlate the atomic- and nanoscale-structure of condensed matter with physical properties (e.g., mechanical, electrical, catalytic, and optical) and functionality forms the core of many disciplines. Directing and controlling materials at the quantum-, atomic-, and molecular-levels creates enormous challenges and opportunities across a wide spectrum of critical technologies, including those involving the generation and use of energy. The workshop identified next generation electron scattering and diffraction instruments that are uniquely positioned to address these grand challenges. The workshop participants identified four key areas where the next generation of such instrumentation would have major impact: A – Multidimensional Visualization of Real Materials B – Atomic-scale Molecular Processes C – Photonic Control of Emergence in Quantum Materials D – Evolving Interfaces, Nucleation, and Mass Transport Real materials are comprised of complex three-dimensional arrangements of atoms and defects that directly determine their potential for energy applications. Understanding real materials requires new capabilities for three-dimensional atomic scale tomography and spectroscopy of atomic and electronic structures with unprecedented sensitivity, and with simultaneous spatial and energy resolution. Many molecules are able to selectively and efficiently convert sunlight into other forms of energy, like heat and electric current, or store it in altered chemical bonds. Understanding and controlling such process at the atomic scale require unprecedented time resolution. One of the grand challenges in condensed matter physics is to understand, and ultimately control, emergent phenomena in novel quantum materials that necessitate developing a new generation of instruments that probe the interplay among spin, charge, orbital, and lattice degrees of freedom with intrinsic time- and length-scale resolutions. Molecules and soft matter require imaging and

  11. Friendship Conflict and the Development of Generalized Physical Aggression in the Early School Years: A Genetically Informed Study of Potential Moderators

    ERIC Educational Resources Information Center

    Salvas, Marie-Claude; Vitaro, Frank; Brendgen, Mara; Dionne, Ginette; Tremblay, Richard E.; Boivin, Michel

    2014-01-01

    Several authors consider high and frequent conflicts between friends during childhood as a serious risk for subsequent conduct problems such as generalized physical aggression toward others (e.g., Kupersmidt, Burchinal, & Patterson, 1995; Sebanc, 2003). Although it seems logical to assume that friendship conflict could have some negative…

  12. The Role of Service-Learning to Promote Early Childhood Physical Education while Examining Its Influence upon the Vocational Call to Teach

    ERIC Educational Resources Information Center

    Miller, Marybeth

    2012-01-01

    Background: The implementation of service-learning as a teaching and learning method has been well grounded in education, yet the discipline of physical education teacher education (PETE) has been slow to establish itself in this experiential learning paradigm. This study examined the role that service-learning plays in teacher candidates'…

  13. Bragg's Law diffraction simulations for electron backscatter diffraction analysis.

    PubMed

    Kacher, Josh; Landon, Colin; Adams, Brent L; Fullwood, David

    2009-08-01

    In 2006, Angus Wilkinson introduced a cross-correlation-based electron backscatter diffraction (EBSD) texture analysis system capable of measuring lattice rotations and elastic strains to high resolution. A variation of the cross-correlation method is introduced using Bragg's Law-based simulated EBSD patterns as strain free reference patterns that facilitates the use of the cross-correlation method with polycrystalline materials. The lattice state is found by comparing simulated patterns to collected patterns at a number of regions on the pattern using the cross-correlation function and calculating the deformation from the measured shifts of each region. A new pattern can be simulated at the deformed state, and the process can be iterated a number of times to converge on the absolute lattice state. By analyzing an iteratively rotated single crystal silicon sample and recovering the rotation, this method is shown to have an angular resolution of approximately 0.04 degrees and an elastic strain resolution of approximately 7e-4. As an example of applications, elastic strain and curvature measurements are used to estimate the dislocation density in a single grain of a compressed polycrystalline Mg-based AZ91 alloy. PMID:19520512

  14. Accelerometer data requirements for reliable estimation of habitual physical activity and sedentary time of children during the early years - a worked example following a stepped approach.

    PubMed

    Bingham, Daniel D; Costa, Silvia; Clemes, Stacy A; Routen, Ash C; Moore, Helen J; Barber, Sally E

    2016-10-01

    This study presents a worked example of a stepped process to reliably estimate the habitual physical activity and sedentary time of a sample of young children. A total of 299 children (2.9 ± 0.6 years) were recruited. Outcome variables were daily minutes of total physical activity, sedentary time, moderate to vigorous physical activity and proportional values of each variable. In total, 282 (94%) provided 3 h of accelerometer data on ≥1 day and were included in a 6-step process: Step-1: determine minimum wear-time; Step-2: process 7-day-data; Step-3: determine the inclusion of a weekend day; Step-4: examine day-to-day variability; Step-5: calculate single day intraclass correlation (ICC) (2,1); Step-6: calculate number of days required to reach reliability. Following the process the results were, Step-1: 6 h was estimated as minimum wear-time of a standard day. Step-2: 98 (32%) children had ≥6 h wear on 7 days. Step-3: no differences were found between weekdays and weekend days (P ≥ 0.05). Step-4: no differences were found between day-to-day variability (P ≥ 0.05). Step-5: single day ICC's (2,1) ranged from 0.48 (total physical activity and sedentary time) to 0.53 (proportion of moderate to vigorous physical activity). Step-6: to reach reliability (ICC = 0.7), 3 days were required for all outcomes. In conclusion following a 7 day wear protocol, ≥6 h on any 3 days was found to have acceptable reliability. The stepped-process offers researchers a method to derive sample-specific wear-time criterion. PMID:26920123

  15. Perceptual information from OVD diffraction security devices

    NASA Astrophysics Data System (ADS)

    Moser, Jean-Frederic; Staub, Rene; Tompkin, Wayne R.

    1996-03-01

    The criteria by which optically variable devices are judged are aesthetic, semantic, security, ergonomic, and physical/chemical. This paper addresses ergonomic aspects which relate to the human vision and perceptual-cognitive system. Applying some pertinent rules may help greatly to improve the image visual information for easier, more straight-forward reception of a persistent security message. We consider two important aspects of the human visual system that help to determine the ergonomic response to visual displays created using optical diffraction. The human visual system aspect treats the retinal source of information, which is the retinal signal produced when an image of the external world is projected on the retina. The other aspect is the underlying information-processing mechanism of our brains and its constructive operations, which yields the final perceptual information. In this paper we consider information processing methods hidden in the biology of our cognition system. Findings on the relationship between physiology and psychology, sensory results and the activities of the optic pathway and subjective brightness sensations can be applied directly in designing images. Some effects are demonstrated by video tape.

  16. Light by light diffraction in vacuum

    SciTech Connect

    Tommasini, Daniele; Michinel, Humberto

    2010-07-15

    We show that a laser beam can be diffracted by a more concentrated light pulse due to quantum vacuum effects. We compute analytically the intensity pattern in a realistic experimental configuration, and discuss how it can be used to measure the parameters describing photon-photon scattering in vacuum. In particular, we show that the quantum electrodynamics prediction can be detected in a single-shot experiment at future 100-PW lasers such as ELI or HIPER. On the other hand, if carried out at one of the present high-power facilities, such as OMEGA EP, this proposal can lead either to the discovery of nonstandard physics or to substantial improvement in the current limits by PVLAS collaboration on the photon-photon cross section at optical wavelengths. This example of manipulation of light by light is simpler to realize and more sensitive than existing, alternative proposals, and can also be used to test Born-Infeld theory or to search for axionlike or minicharged particles.

  17. Studies of V, Nb, Cr, and Zr substituted 2:17 compounds and their carbides using neutron diffraction

    SciTech Connect

    Luo, H.; Hu, Z.; Chen, M.; Yelon, W.B.; Marasinghe, G.K.; Ezekwenna, P.C.; James, W.J.; Chang, W.C.; Tsai, S.H.

    1997-04-01

    Samples of Nd{sub 2}Fe{sub 17{minus}x}T{sub x}C{sub y} with T=V, Nb, Cr, and Zr were prepared by melting of the constituent elements including C and studied by neutron diffraction. Comparing with their uncarbided counterparts, we found that the substituents transfer, more or less, from the {ital 6c} site to the {ital 18f} and {ital 18h} sites with the introduction of C atoms. This behavior appears to relate to the electronegativities between the C atoms and the early transition series elements because the {ital 18f} and {ital 18h} sites are near neighbors of the interstitial C site. However, the C effects in the V, Nb, Cr, and Zr samples are not as strong as those in Ti samples. SQUID measurements show that the Curie temperatures of these samples depend on both the interstitial C atoms and the substituents. {copyright} {ital 1997 American Institute of Physics.}

  18. Early Childhood Special Music Education

    ERIC Educational Resources Information Center

    Darrow, Alice-Ann

    2011-01-01

    The process of early intervention is a critical component of Early Childhood Special Music Education. Early intervention is the process of providing services, education, and support to young children who have disabilities or to children who are at-risk of developing needs that may affect their physical, cognitive, or emotional development. The…

  19. Hard diffraction with dynamic gap survival

    NASA Astrophysics Data System (ADS)

    Rasmussen, Christine O.; Sjöstrand, Torbjörn

    2016-02-01

    We present a new framework for the modelling of hard diffraction in pp and poverline{p} collisions. It starts from the the approach pioneered by Ingelman and Schlein, wherein the single diffractive cross section is factorized into a Pomeron flux and a Pomeron PDF. To this it adds a dynamically calculated rapidity gap survival factor, derived from the modelling of multiparton interactions. This factor is not relevant for diffraction in ep collisions, giving non-universality between HERA and Tevatron diffractive event rates. The model has been implemented in P ythia 8 and provides a complete description of the hadronic state associated with any hard single diffractive process. Comparisons with poverline{p} and pp data reveal improvement in the description of single diffractive events.

  20. Optimizing Crystal Volume for Neutron Diffraction

    NASA Technical Reports Server (NTRS)

    Snell, Edward H.; vanderWoerd, Mark; Damon, Michael; Judge, Russell, A.; Myles, Dean; Meilleur, F.

    2006-01-01

    Neutron diffraction is uniquely sensitive to hydrogen positions and protonation state. In that context structural information from neutron data is complementary to that provided through X-ray diffraction. However, there are practical obstacles to overcome in fully exploiting the potential of neutron diffraction, Le. low flux and weak scattering. Several approaches are available to overcome these obstacles and we have investigated the simplest: increasing the diffracting volume of the crystals. Volume is a quantifiable metric that is well suited for experiment design and optimization techniques. By using response surface methods we have optimized xylose isomerase crystal volume, enabling neutron diffraction while we determined the crystallization parameters with the minimum of experiments. Our results suggest a systematic means of enabling neutron diffraction studies for a larger number of samples that require information on hydrogen position and/or protonation state.

  1. Twenty years of diffraction at the Tevatron

    SciTech Connect

    Goulianos, K.; /Rockefeller U.

    2005-10-01

    Results on diffractive particle interactions from the Fermilab Tevatron {bar p}p collider are placed in perspective through a QCD inspired phenomenological approach, which exploits scaling and factorization properties observed in data. The results discussed are those obtained by the CDF Collaboration from a comprehensive set of single, double, and multigap soft and hard diffraction processes studied during the twenty year period since 1985, when the CDF diffractive program was proposed and the first Blois Workshop was held.

  2. Diffraction gratings used as identifying markers

    DOEpatents

    Deason, V.A.; Ward, M.B.

    1991-03-26

    A finely detailed diffraction grating is applied to an object as an identifier or tag which is unambiguous, difficult to duplicate, or remove and transfer to another item, and can be read and compared with prior readings with relative ease. The exact pattern of the diffraction grating is mapped by diffraction moire techniques and recorded for comparison with future readings of the same grating. 7 figures.

  3. Aircraft noise propagation. [sound diffraction by wings

    NASA Technical Reports Server (NTRS)

    Hadden, W. J.; Pierce, A. D.

    1978-01-01

    Sound diffraction experiments conducted at NASA Langley Research Center to study the acoustical implications of the engine over wing configuration (noise-shielding by wing) and to provide a data base for assessing various theoretical approaches to the problem of aircraft noise reduction are described. Topics explored include the theory of sound diffraction around screens and wedges; the scattering of spherical waves by rectangular patches; plane wave diffraction by a wedge with finite impedence; and the effects of ambient flow and distribution sources.

  4. Convex Diffraction Grating Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Chrisp, Michael P. (Inventor)

    1999-01-01

    A 1:1 Offner mirror system for imaging off-axis objects is modified by replacing a concave spherical primary mirror that is concentric with a convex secondary mirror with two concave spherical mirrors M1 and M2 of the same or different radii positioned with their respective distances d1 and d2 from a concentric convex spherical diffraction grating having its grooves parallel to the entrance slit of the spectrometer which replaces the convex secondary mirror. By adjusting their distances d1 and d2 and their respective angles of reflection alpha and beta, defined as the respective angles between their incident and reflected rays, all aberrations are corrected without the need to increase the spectrometer size for a given entrance slit size to reduce astigmatism, thus allowing the imaging spectrometer volume to be less for a given application than would be possible with conventional imaging spectrometers and still give excellent spatial and spectral imaging of the slit image spectra over the focal plane.

  5. Sub-wavelength diffractive optics

    SciTech Connect

    Warren, M.E.; Wendt, J.R.; Vawter, G.A.

    1998-03-01

    This report represents the completion of a three-year Laboratory-Directed Research and Development (LDRD) program to investigate sub-wavelength surface relief structures fabricated by direct-write e-beam technology as unique and very high-efficiency optical elements. A semiconductor layer with sub-wavelength sized etched openings or features can be considered as a layer with an effective index of refraction determined by the fraction of the surface filled with semiconductor relative to the fraction filled with air or other material. Such as a layer can be used to implement planar gradient-index lenses on a surface. Additionally, the nanometer-scale surface structures have diffractive properties that allow the direct manipulation of polarization and altering of the reflective properties of surfaces. With this technology a single direct-write mask and etch can be used to integrate a wide variety of optical functions into a device surface with high efficiencies; allowing for example, direct integration of polarizing optics into the surface with high efficiencies; allowing for example, direct integration of polarizing optics into the surfaces of devices, forming anti-reflection surfaces or fabricating high-efficiency, high-numerical aperture lenses, including integration inside vertical semiconductor laser cavities.

  6. Large aperture diffractive space telescope

    DOEpatents

    Hyde, Roderick A.

    2001-01-01

    A large (10's of meters) aperture space telescope including two separate spacecraft--an optical primary objective lens functioning as a magnifying glass and an optical secondary functioning as an eyepiece. The spacecraft are spaced up to several kilometers apart with the eyepiece directly behind the magnifying glass "aiming" at an intended target with their relative orientation determining the optical axis of the telescope and hence the targets being observed. The objective lens includes a very large-aperture, very-thin-membrane, diffractive lens, e.g., a Fresnel lens, which intercepts incoming light over its full aperture and focuses it towards the eyepiece. The eyepiece has a much smaller, meter-scale aperture and is designed to move along the focal surface of the objective lens, gathering up the incoming light and converting it to high quality images. The positions of the two space craft are controlled both to maintain a good optical focus and to point at desired targets which may be either earth bound or celestial.

  7. Analysis of the role of diffraction in topographic site effects using boundary element techniques

    NASA Astrophysics Data System (ADS)

    Gomez, Juan; Restrepo, Doriam; Jaramillo, Juan; Valencia, Camilo

    2013-10-01

    The role played by the diffraction field on the problem of seismic site effects is studied. For that purpose we solve and analyze simple scattering problems under P and SV in-plane wave assumptions, using two well known direct boundary-element-based numerical methods. After establishing the difference between scattered and diffracted motions, and introducing the concept of artificious and physically based incoming fields, we obtain the amplitude of the Fourier spectra for the diffracted part of the response: this is achieved after establishing the connection between the spatial distribution of the transfer function over the studied simple topographies and the diffracted field. From the numerical simulations it is observed that this diffracted part of the response is responsible for the amplification of the surface ground motions due to the geometric effect. Furthermore, it is also found that the diffraction field sets in a fingerprint of the topographic effect in the total ground motions. These conclusions are further supported by observations in the time-domain in terms of snapshots of the propagation patterns over the complete computational model. In this sense the geometric singularities are clearly identified as sources of diffraction and for the considered range of dimensionless frequencies it is evident that larger amplifications are obtained for the geometries containing a larger number of diffraction sources thus resulting in a stronger topographic effect. The need for closed-form solutions of canonical problems to construct a robust analysis method based on the diffraction field is identified.

  8. Diffractively corrected counter-rotating Risley prisms.

    PubMed

    Nie, Xin; Yang, Hongfang; Xue, Changxi

    2015-12-10

    Using the vector refraction equation and the vector diffraction equation, we obtain the expressions of the direction cosines of the refractive rays for the two wedge prisms, and the direction cosines of the diffractive rays for two wedge grisms, in which diffractive gratings were etched into the prism faces to correct the chromatic aberrations. A mathematical model between the two vector equations is proposed to compare the difference angle chromatic aberrations when the Risley prisms/grisms are rotating at different angles. We conclude that the use of diffractively corrected prisms offers a new method to correct chromatic aberrations in Risley prisms. PMID:26836873

  9. Broadband diffractive lens or imaging element

    DOEpatents

    Ceglio, N.M.; Hawryluk, A.M.; London, R.A.; Seppala, L.G.

    1993-10-26

    A broadband diffractive lens or imaging element produces a sharp focus and/or a high resolution image with broad bandwidth illuminating radiation. The diffractive lens is sectored or segmented into regions, each of which focuses or images a distinct narrowband of radiation but all of which have a common focal length. Alternatively, a serial stack of minus filters, each with a diffraction pattern which focuses or images a distinct narrowband of radiation but all of which have a common focal length, is used. The two approaches can be combined. Multifocal broadband diffractive elements can also be formed. Thin film embodiments are described. 21 figures.

  10. Electron Diffraction Using Transmission Electron Microscopy

    PubMed Central

    Bendersky, Leonid A.; Gayle, Frank W.

    2001-01-01

    Electron diffraction via the transmission electron microscope is a powerful method for characterizing the structure of materials, including perfect crystals and defect structures. The advantages of electron diffraction over other methods, e.g., x-ray or neutron, arise from the extremely short wavelength (≈2 pm), the strong atomic scattering, and the ability to examine tiny volumes of matter (≈10 nm3). The NIST Materials Science and Engineering Laboratory has a history of discovery and characterization of new structures through electron diffraction, alone or in combination with other diffraction methods. This paper provides a survey of some of this work enabled through electron microscopy.

  11. Broadband diffractive lens or imaging element

    DOEpatents

    Ceglio, Natale M.; Hawryluk, Andrew M.; London, Richard A.; Seppala, Lynn G.

    1993-01-01

    A broadband diffractive lens or imaging element produces a sharp focus and/or a high resolution image with broad bandwidth illuminating radiation. The diffractive lens is sectored or segmented into regions, each of which focuses or images a distinct narrowband of radiation but all of which have a common focal length. Alternatively, a serial stack of minus filters, each with a diffraction pattern which focuses or images a distinct narrowband of radiation but all of which have a common focal length, is used. The two approaches can be combined. Multifocal broadband diffractive elements can also be formed. Thin film embodiments are described.

  12. Broadband diffractive lens or imaging element

    DOEpatents

    Ceglio, Natale M.; Hawryluk, Andrew M.; London, Richard A.; Seppala, Lynn G.

    1991-01-01

    A broadband diffractive lens or imaging element produces a sharp focus and/or a high resolution image with broad bandwidth illuminating radiation. The diffractive lens is sectored or segmented into regions, each of which focuses or images a distinct narrowband of radiation but all of which have a common focal length. Alternatively, a serial stack of minus filters, each with a diffraction pattern which focuses or images a distinct narrowband of radiation but all of which have a common focal length, is used. The two approaches can be combined. Multifocal broadband diffractive elements can also be formed.

  13. Defining Electron Backscatter Diffraction Resolution

    SciTech Connect

    El-Dasher, B S; Rollett, A D

    2005-02-07

    Automated electron backscatter diffraction (EBSD) mapping systems have existed for more than 10 years [1,2], and due to their versatility in characterizing multiple aspects of microstructure, they have become an important tool in microscale crystallographic studies. Their increasingly widespread use however raises questions about their accuracy in both determining crystallographic orientations, as well as ensuring that the orientation information is spatially correct. The issue of orientation accuracy (as defined by angular resolution) has been addressed previously [3-5]. While the resolution of EBSD systems is typically quoted to be on the order of 1{sup o}, it has been shown that by increasing the pattern quality via acquisition parameter adjustment, the angular resolution can be improved to sub-degree levels. Ultimately, the resolution is dependent on how it is identified. In some cases it can be identified as the orientation relative to a known absolute, in others as the misorientation between nearest neighbor points in a scan. Naturally, the resulting values can be significantly different. Therefore, a consistent and universal definition of resolution that can be applied to characterize any EBSD system is necessary, and is the focus of the current study. In this work, a Phillips (FEI) XL-40 FEGSEM coupled to a TexSEM Laboratories OIM system was used. The pattern capturing hardware consisted of both a 512 by 512 pixel SIT CCD camera and a 1300 by 1030 pixel Peltier cooled CCD camera. Automated scans of various sizes, each consisting of 2500 points, were performed on a commercial-grade single crystal silicon wafer used for angular resolution measurements. To adequately quantify angular resolution for all possible EBSD applications we define two angular values. The first is {omega}{sub center}, the mean of the misorientation angle distribution between all scan points and the scan point coincident to the calibration source (typically the scan center). The {omega

  14. New software to model energy dispersive X-ray diffraction in polycrystalline materials

    NASA Astrophysics Data System (ADS)

    Ghammraoui, B.; Tabary, J.; Pouget, S.; Paulus, C.; Moulin, V.; Verger, L.; Duvauchelle, Ph.

    2012-02-01

    Detection of illicit materials, such as explosives or drugs, within mixed samples is a major issue, both for general security and as part of forensic analyses. In this paper, we describe a new code simulating energy dispersive X-ray diffraction patterns in polycrystalline materials. This program, SinFullscat, models diffraction of any object in any diffractometer system taking all physical phenomena, including amorphous background, into account. Many system parameters can be tuned: geometry, collimators (slit and cylindrical), sample properties, X-ray source and detector energy resolution. Good agreement between simulations and experimental data was obtained. Simulations using explosive materials indicated that parameters such as the diffraction angle or the energy resolution of the detector have a significant impact on the diffraction signature of the material inspected. This software will be a convenient tool to test many diffractometer configurations, providing information on the one that best restores the spectral diffraction signature of the materials of interest.

  15. Genetic algorithm for chromaticity correction in diffraction limited storage rings

    NASA Astrophysics Data System (ADS)

    Ehrlichman, M. P.

    2016-04-01

    A multiobjective genetic algorithm is developed for optimizing nonlinearities in diffraction limited storage rings. This algorithm determines sextupole and octupole strengths for chromaticity correction that deliver optimized dynamic aperture and beam lifetime. The algorithm makes use of dominance constraints to breed desirable properties into the early generations. The momentum aperture is optimized indirectly by constraining the chromatic tune footprint and optimizing the off-energy dynamic aperture. The result is an effective and computationally efficient technique for correcting chromaticity in a storage ring while maintaining optimal dynamic aperture and beam lifetime.

  16. Time Domain Version of the Uniform Geometrical Theory of Diffraction

    NASA Astrophysics Data System (ADS)

    Rousseau, Paul R.

    1995-01-01

    A time domain (TD) version of the uniform geometrical theory of diffraction which is referred to as the TD-UTD is developed to analyze the transient electromagnetic scattering from perfectly conducting objects that are large in terms of pulse width. In particular, the scattering from a perfectly conducting arbitrary curved wedge and an arbitrary smooth convex surface are treated in detail. Note that the canonical geometries of a circular cylinder and a sphere are special cases of the arbitrary smooth convex surface. These TD -UTD solutions are obtained in the form of relatively simple analytical expressions valid for early to intermediate times. The geometries treated here can be used to build up a transient solution to more complex radiating objects via space-time localization, in exactly the same way as is done by invoking spatial localization properties in the frequency domain UTD. The TD-UTD provides the response due to an excitation of a general astigmatic impulsive wavefront with any polarization. This generalized impulse response may then be convolved with other excitation time pulses, to find even more general solutions due to other excitation pulses. Since the TD-UTD uses the same rays as the frequency domain UTD, it provides a simple picture for transient radiation or scattering and is therefore just as physically appealing as the frequency domain UTD. The formulation of an analytic time transform (ATT), which produces an analytic time signal given a frequency response function, is given here. This ATT is used because it provides a very efficient method of inverting the asymptotic high frequency UTD representations to obtain the corresponding TD-UTD expressions even when there are special UTD transition functions which may not be well behaved at the low frequencies; also, using the ATT avoids the difficulties associated with the inversion of UTD ray fields that traverse line or smooth caustics. Another useful aspect of the ATT is the ability to perform an

  17. The diffraction limit of an optical spectrum analyzer

    NASA Astrophysics Data System (ADS)

    Kolobrodov, V. G.; Tymchik, G. S.; Kolobrodov, M. S.

    2015-11-01

    This article examines a systematic error that occurs in optical spectrum analyzers and is caused by Fresnel approximation. The aim of the article is to determine acceptable errors of spatial frequency measurement in signal spectrum. The systematic error of spatial frequency measurement has been investigated on the basis of a physical and mathematical model of a coherent spectrum analyzer. It occurs as a result of the transition from light propagation in free space to Fresnel diffraction. Equations used to calculate absolute and relative measurement errors depending on a diffraction angle have been obtained. It allows us to determine the limits of the spectral range according to the given relative error of the spatial frequency measurement.

  18. Incorporating mask topography edge diffraction in photolithography simulations.

    PubMed

    Tirapu-Azpiroz, Jaione; Yablonovitch, Eli

    2006-04-01

    In deep ultraviolet lithography simulations, conventional application of Kirchhoff's boundary conditions on the mask surface provides the so-called "thin-mask" approximation of the object field. Current subwavelength lithographic operation, however, places a serious limitation on this approximation, which fails to account for the topographical, or "thick-mask," effects. In this paper, a new simulation model is proposed that is theoretically founded on the well-established physical theory of diffraction. This model relies on the key result that diffraction effects can be interpreted as an intrinsic edge property, and modeled with just two fixed parameters: width and transmission coefficient of a locally determined boundary layer applied to each chrome edge. The proposed model accurately accounts for thick-mask effects of the fields on the mask, greatly improving the accuracy of aerial image simulations in photolithography, while maintaining a reasonable computational cost. PMID:16604762

  19. Calculation of the diffraction efficiency on concave gratings based on Fresnel-Kirchhoff's diffraction formula.

    PubMed

    Huang, Yuanshen; Li, Ting; Xu, Banglian; Hong, Ruijin; Tao, Chunxian; Ling, Jinzhong; Li, Baicheng; Zhang, Dawei; Ni, Zhengji; Zhuang, Songlin

    2013-02-10

    Fraunhofer diffraction formula cannot be applied to calculate the diffraction wave energy distribution of concave gratings like plane gratings because their grooves are distributed on a concave spherical surface. In this paper, a method based on the Kirchhoff diffraction theory is proposed to calculate the diffraction efficiency on concave gratings by considering the curvature of the whole concave spherical surface. According to this approach, each groove surface is divided into several limited small planes, on which the Kirchhoff diffraction field distribution is calculated, and then the diffraction field of whole concave grating can be obtained by superimposition. Formulas to calculate the diffraction efficiency of Rowland-type and flat-field concave gratings are deduced from practical applications. Experimental results showed strong agreement with theoretical computations. With the proposed method, light energy can be optimized to the expected diffraction wave range while implementing aberration-corrected design of concave gratings, particularly for the concave blazed gratings. PMID:23400074

  20. Characterization of the diffraction properties of quantum-dot-array diffraction grating

    NASA Astrophysics Data System (ADS)

    Wang, Chuanke; Kuang, Longyu; Wang, Zhebin; Liu, Shenye; Ding, Yongkun; Cao, Leifeng; Foerster, Eckhart; Wang, Deqiang; Xie, Changqing; Ye, Tianchun

    2007-05-01

    A new dispersive element named as quantum-dot-array diffraction grating [L. F. Cao, China patent No. 200410081499 (August 10, 2004)] for visible light has been developed and characterized experimentally. A large number of quantum dots distributed on a substrate as sinusoidal function can be used to diffract x rays without higher-order diffraction. The experimental patterns show that the higher-order diffractions which inevitably exist in the spectrum recorded using traditional diffraction gratings can be eliminated effectively by this newly designed element. It indicates that quantum-dot-array diffraction grating could be an attractive alternative of presently used diffraction grating in soft x-ray spectroscopy application to get rid of the higher-order diffraction distortions.

  1. Characterization of the diffraction properties of quantum-dot-array diffraction grating

    SciTech Connect

    Wang Chuanke; Kuang Longyu; Wang Zhebin; Liu Shenye; Ding Yongkun; Cao Leifeng; Foerster, Eckhart; Wang Deqiang; Xie Changqing; Ye Tianchun

    2007-05-15

    A new dispersive element named as quantum-dot-array diffraction grating [L. F. Cao, China patent No. 200410081499 (August 10, 2004)] for visible light has been developed and characterized experimentally. A large number of quantum dots distributed on a substrate as sinusoidal function can be used to diffract x rays without higher-order diffraction. The experimental patterns show that the higher-order diffractions which inevitably exist in the spectrum recorded using traditional diffraction gratings can be eliminated effectively by this newly designed element. It indicates that quantum-dot-array diffraction grating could be an attractive alternative of presently used diffraction grating in soft x-ray spectroscopy application to get rid of the higher-order diffraction distortions.

  2. CMS results on exclusive and diffractive production

    SciTech Connect

    Alves, Gilvan A.

    2015-04-10

    We present recent CMS measurements of diffractive and exclusive processes, using data collected at 7 TeV at the LHC. Measurements of soft single- and double-diffractive cross sections are presented, as well as measurements of photon-induced processes including studies of exclusive WW production via photon-photon exchange.

  3. White-Light Diffraction with a CD

    ERIC Educational Resources Information Center

    Ivanov, Dragia Trifonov; Nikolaev, Stefan

    2010-01-01

    Various wave optics experiments can be carried out using an ordinary compact disc. The CD is suitable for use as a diffraction grating. For instance, a standard CD (700 MB) has 625 lines/mm. In this article, the authors describe two white-light diffraction demonstrations for a large audience, realizable using a CD (as reflection or transmission…

  4. Liquid-Crystal Point-Diffraction Interferometer

    NASA Technical Reports Server (NTRS)

    Mercer, Carolyn R.

    1996-01-01

    Liquid-crystal point-diffraction interferometer (LCPDI) invented to combine flexible control of liquid-crystal phase-shifts with robustness of point-diffraction interferometers. Produces interferograms indicative of shapes of wavefronts of laser beams having passed through or reflected from objects of interest. Interferograms combined in computers to produce phase maps describing wavefronts.

  5. Unusual features of Drell-Yan diffraction

    SciTech Connect

    Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan; Tarasov, A. V.

    2006-12-01

    The cross section of the diffractive Drell-Yan (DY) process, pp{yields}llXp, where the system llX is separated by a large rapidity gap from the recoil proton, is calculated in the light-cone dipole approach. This process reveals unusual features, quite different from what is known for diffractive deeply inelastic scattering (DIS) and non-Abelian radiation: (i) the diffractive radiation of a heavy dilepton by a quark vanishes in the forward direction; (ii) the diffractive production of a dilepton is controlled by the large hadronic radius; (iii) in contrast with DIS where diffraction is predominantly soft, the diffractive DY reaction is semihard-semisoft; (iv) as a result of the saturated shape of the dipole cross section, the fraction of diffractive DY events steeply falls with energy but rises as a function of the hard scale. These features are common for other Abelian bremsstrahlung processes (higgsstrahlung, Z-strahlung, etc.). Measurements of diffractive DY processes at modern colliders would be a sensitive probe for the shape of the dipole cross section at large separations.

  6. Structure refinement from precession electron diffraction data.

    PubMed

    Palatinus, Lukáš; Jacob, Damien; Cuvillier, Priscille; Klementová, Mariana; Sinkler, Wharton; Marks, Laurence D

    2013-03-01

    Electron diffraction is a unique tool for analysing the crystal structures of very small crystals. In particular, precession electron diffraction has been shown to be a useful method for ab initio structure solution. In this work it is demonstrated that precession electron diffraction data can also be successfully used for structure refinement, if the dynamical theory of diffraction is used for the calculation of diffracted intensities. The method is demonstrated on data from three materials - silicon, orthopyroxene (Mg,Fe)(2)Si(2)O(6) and gallium-indium tin oxide (Ga,In)(4)Sn(2)O(10). In particular, it is shown that atomic occupancies of mixed crystallographic sites can be refined to an accuracy approaching X-ray or neutron diffraction methods. In comparison with conventional electron diffraction data, the refinement against precession diffraction data yields significantly lower figures of merit, higher accuracy of refined parameters, much broader radii of convergence, especially for the thickness and orientation of the sample, and significantly reduced correlations between the structure parameters. The full dynamical refinement is compared with refinement using kinematical and two-beam approximations, and is shown to be superior to the latter two. PMID:23403968

  7. Diffraction experiments with infrared remote controls

    NASA Astrophysics Data System (ADS)

    Kuhn, Jochen; Vogt, Patrik

    2012-02-01

    In this paper we describe an experiment in which radiation emitted by an infrared remote control is passed through a diffraction grating. An image of the diffraction pattern is captured using a cell phone camera and then used to determine the wavelength of the radiation.

  8. RENORM predictions of diffraction at LHC confirmed

    SciTech Connect

    Goulianos, Konstantin

    2015-04-10

    The RENORM model predictions of diffractive, total, and total-inelastic cross sections at the LHC are confirmed by recent measurements. The predictions of several other available models are discussed, highlighting their differences from RENORM, mainly arising from the way rapidity gap formation, low- and high-mass diffraction, unitarization, and hadronization are implemented.

  9. Intensity Measurements in a Fresnel Diffraction Pattern

    ERIC Educational Resources Information Center

    Boyer, R.; Fortin, E.

    1972-01-01

    Describes an undergraduate optics laboratory experiment to verify the law of intensity in the Fesnel diffraction of a thin wire. A gas laser as light source and a photocell as detector scan the diffraction pattern. The agreement with the theoretical pattern is remarkably good. (Author/TS)

  10. The effect of machining error on the diffraction efficiency of refraction and diffractive optical element

    NASA Astrophysics Data System (ADS)

    Gao, Long; Xue, Changxi; Yang, Hongfang; Nie, Xin

    2014-08-01

    According to the expression of the phase delay and diffraction efficiency of the diffractive optical elements(DOEs), the expression of diffraction efficiency of refraction and diffractive optical element with the tilt and decenter error in fabrication process was presented in this paper. Analysis results show, in the wavelength band of 501nm-554nm, the cycle of 500μm, the center wavelength of 521nm, when the tilt angleα increases form 0° to9.8° , the diffraction efficiency is above 99%; when the tilt angleα increases form 9.8° to 29.7° , diffraction efficiency is above 92.5%; when the tilt angleα is above 29.7° , the diffraction efficiency declines rapidly, diffraction efficiency is 0 when the tilt angleα is above 58° . When the decenter Δ increases form 0nm to 21.6μm,the diffraction efficiency is above 98%; when the decenter Δ increases form 21.6nm to 63.3μm, the diffraction efficiency is above 90%; when the decenter Δ is above 63.3μm, the diffraction efficiency declines rapidly, diffraction efficiency is 0 when the he decenter Δ is above 241.7μm. To sum up the results of analysis,mathematical analysis model of the relationship between the decenter and tilt error of diffractive optical element in processing and the diffraction efficiency can be used to guide the design of the refraction and diffractive hybrid optical system comprising the diffractive optical element.

  11. Nonlinear diffraction in orientation-patterned semiconductors.

    PubMed

    Karpinski, Pawel; Chen, Xin; Shvedov, Vladlen; Hnatovsky, Cyril; Grisard, Arnaud; Lallier, Eric; Luther-Davies, Barry; Krolikowski, Wieslaw; Sheng, Yan

    2015-06-01

    This work represents experimental demonstration of nonlinear diffraction in an orientation-patterned semiconducting material. By employing a new transverse geometry of interaction, three types of second-order nonlinear diffraction have been identified according to different configurations of quasi-phase matching conditions. Specifically, nonlinear Čerenkov diffraction is defined by the longitudinal quasi-phase matching condition, nonlinear Raman-Nath diffraction satisfies only the transverse quasi-phase matching condition, and nonlinear Bragg diffraction fulfils the full vectorial quasi-phase matching conditions. The study extends the concept of transverse nonlinear parametric interaction toward infrared frequency conversion in semiconductors. It also offers an effective nondestructive method to visualise and diagnose variations of second-order nonlinear coefficients inside semiconductors. PMID:26072847

  12. Diffraction in time: An exactly solvable model

    NASA Astrophysics Data System (ADS)

    Goussev, Arseni

    2014-03-01

    In optics, diffraction is typically portrayed as deflection of light incident upon an obstacle with sharp boundaries, that can not be accounted for by reflection or refraction. Interestingly, quantum mechanics allows for an additional, intrinsically time-dependent manifestation of the phenomenon: Owing to the dispersive nature of quantum matter waves, sudden changes in boundary conditions may cause the particle wave function to develop interference fringes akin to those in stationary (optical) diffraction problems. This phenomenon, pioneered in 1952 by Moshinsky [Phys. Rev. 88, 625 (1952)] and presently referred to as ``diffraction in time,'' is at the heart of a vibrant area of experimental and theoretical research concerned with quantum transients. In my talk, I will introduce a new versatile exactly-solvable model of diffraction in time. The model describes dynamics of a quantum particle in the presence of an absorbing time-dependent barrier, and enables a quantitative description of diffraction and interference patterns in a large variety of setups.

  13. Fraunhofer diffraction by arbitrary-shaped obstacles.

    PubMed

    Malinka, Aleksey V; Zege, Eleonora P

    2009-08-01

    We consider Fraunhofer diffraction by an ensemble of large arbitrary-shaped screens that are randomly oriented in the plane of a wavefront and have edges of arbitrary shape. It is shown that far outside the main diffraction peak the differential scattering cross section behaves asymptotically as theta(-3), where theta is the diffraction angle. Moreover, the differential scattering cross section depends only on the length of the contours bordering the screens and does not depend on the shape of the obstacles. As both strictly forward and total diffraction cross sections are specified by obstacle area only, the differential cross section of size-distributed obstacles is expected to be nearly independent of obstacle shape over the entire region of the diffraction angles. PMID:19649110

  14. The role of adolescent nutrition and physical activity in the prediction of verbal intelligence during early adulthood: a genetically informed analysis of twin pairs.

    PubMed

    Jackson, Dylan B; Beaver, Kevin M

    2015-01-01

    A large body of research has revealed that nutrition and physical activity influence brain functioning at various stages of the life course. Nevertheless, very few studies have explored whether diet and exercise influence verbal intelligence as youth transition from adolescence into young adulthood. Even fewer studies have explored the link between these health behaviors and verbal intelligence while accounting for genetic and environmental factors that are shared between siblings. Employing data from the National Longitudinal Study of Adolescent Health, the current study uses a sample of same-sex twin pairs to test whether youth who engage in poorer fitness and nutritional practices are significantly more likely to exhibit reduced verbal intelligence during young adulthood. The results suggests that, independent of the effects of genetic and shared environmental factors, a number of nutritional and exercise factors during adolescence influence verbal intelligence during adulthood. Limitations are noted and suggestions for future research are outlined. PMID:25568969

  15. The Role of Adolescent Nutrition and Physical Activity in the Prediction of Verbal Intelligence during Early Adulthood: A Genetically Informed Analysis of Twin Pairs

    PubMed Central

    Jackson, Dylan B.; Beaver, Kevin M.

    2015-01-01

    A large body of research has revealed that nutrition and physical activity influence brain functioning at various stages of the life course. Nevertheless, very few studies have explored whether diet and exercise influence verbal intelligence as youth transition from adolescence into young adulthood. Even fewer studies have explored the link between these health behaviors and verbal intelligence while accounting for genetic and environmental factors that are shared between siblings. Employing data from the National Longitudinal Study of Adolescent Health, the current study uses a sample of same-sex twin pairs to test whether youth who engage in poorer fitness and nutritional practices are significantly more likely to exhibit reduced verbal intelligence during young adulthood. The results suggests that, independent of the effects of genetic and shared environmental factors, a number of nutritional and exercise factors during adolescence influence verbal intelligence during adulthood. Limitations are noted and suggestions for future research are outlined. PMID:25568969

  16. Diffraction-assisted micropatterning of silicon surfaces by ns-laser irradiation

    SciTech Connect

    Haro-Poniatowski, E. Acosta-Zepeda, C.; Mecalco, G.; Hernández-Pozos, J. L.; Batina, N.; Morales-Reyes, I.; Bonse, J.

    2014-06-14

    Single-pulse (532 nm, 8 ns) micropatterning of silicon with nanometric surface modulation is demonstrated by irradiating through a diffracting pinhole. The irradiation results obtained at fluences above the melting threshold are characterized by scanning electron and scanning force microscopy and reveal a good agreement with Fresnel diffraction theory. The physical mechanism is identified and discussed on basis of both thermocapillary and chemicapillary induced material transport during the molten state of the surface.

  17. Transient x-ray diffraction used to diagnose shock compressed Si crystals on the Nova laser

    SciTech Connect

    Kalantar, D.H.; Chandler, E.A.; Colvin, J.D.; Lee, R.; Remington, B.A.; Weber, S.V.; Wiley, L.G.; Hauer, A.; Wark, J.S.; Loveridge, A.; Failor, B.H.; Meyers, M.A.; Ravichandran, G.

    1999-01-01

    Transient x-ray diffraction is used to record time-resolved information about the shock compression of materials. This technique has been applied on Nova shock experiments driven using a hohlraum x-ray drive. Data were recorded from the shock release at the free surface of a Si crystal, as well as from Si at an embedded ablator/Si interface. Modeling has been done to simulate the diffraction data incorporating the strained crystal rocking curves and Bragg diffraction efficiencies. Examples of the data and post-processed simulations are presented. {copyright} {ital 1999 American Institute of Physics.}

  18. Design and Development of Binary Diffractive Germanium Lens by Thin Film Deposition

    NASA Astrophysics Data System (ADS)

    Alshami, M.; Wabby, A.; Mousselly, M. F.

    2015-11-01

    The design and development of infrared (λ: [8]-[12] μm) binary diffractive germanium lens (BDGL) by two - steps thin film deposition (Physical vapor deposition (PVD) technique) is presented. The optical design of the required elements using the optical design code Zemax, the design of the 4 steps binary surface and its required metallic masks using the programming language Delphi, the procedures of fabrication, and the measurement of the resulting profile, were presented. The comparison between the refractive/diffractive lenses by measuring the minimum resolvable temperature difference (MRTD) shows the advantages of binary diffractive surface.

  19. Simulation and study of Fresnel diffraction for arbitrary two-dimensional apertures

    SciTech Connect

    Dauger, D.E.

    1996-11-01

    A stable, efficient algorithm to calculate numerically a Fresnel diffraction image, given any two-dimensional aperture or obstacle, is introduced. The algorithm predicts both the intensity and relative phase of the image. An alternate faster algorithm is presented for a limited class of apertures. Also examined are images formed from a variety of aperture shapes. Using this computational technique, plots on the complex plane are shown to give insight into Fresnel diffraction. With additional modifications to accept parameters from an experimental apparatus, the algorithms model Fresnel diffraction for laboratory situations. In addition, the algorithms are suitable for numerical implementation on personal computers. {copyright} {ital 1996 American Institute of Physics.}

  20. Support for a special symposium to highlight the research of early career women physical chemists at the 2011 fall ACS nationall meeting, Aug 28-Sept

    SciTech Connect

    Geraldine Richmond

    2012-12-19

    The symposium was well attended during the 4-day symposium. The invited speakers were primarily women in early career stage (~4-8 years) with a few senior women and men as invited speakers or session chairs. Included in each day was a Poster Session for graduate students and a lunch in which the turn out was strong and the posters presented encouraged much of dialogue with the invited speakers, guests and others attending the ACS meeting and wanted to discuss the student’s research and meet with the speakers. Most all speakers and participants were very positive about the sessions and expressed that the funding to cover some expenses made it possible for them to attend the conference and the poster session luncheon. There was a total of 51 presenters, below are the speakers and their abstracts, in order presented:

  1. Remote Laser Diffraction Particle Size Distribution Analyzer

    SciTech Connect

    Batcheller, Thomas Aquinas; Huestis, Gary Michael; Bolton, Steven Michael

    2001-03-01

    In support of a radioactive slurry sampling and physical characterization task, an “off-the-shelf” laser diffraction (classical light scattering) particle size analyzer was utilized for remote particle size distribution (PSD) analysis. Spent nuclear fuel was previously reprocessed at the Idaho Nuclear Technology and Engineering Center (INTEC—formerly recognized as the Idaho Chemical Processing Plant) which is on DOE’s INEEL site. The acidic, radioactive aqueous raffinate streams from these processes were transferred to 300,000 gallon stainless steel storage vessels located in the INTEC Tank Farm area. Due to the transfer piping configuration in these vessels, complete removal of the liquid can not be achieved. Consequently, a “heel” slurry remains at the bottom of an “emptied” vessel. Particle size distribution characterization of the settled solids in this remaining heel slurry, as well as suspended solids in the tank liquid, is the goal of this remote PSD analyzer task. A Horiba Instruments Inc. Model LA-300 PSD analyzer, which has a 0.1 to 600 micron measurement range, was modified for remote application in a “hot cell” (gamma radiation) environment. This technology provides rapid and simple PSD analysis, especially down in the fine and microscopic particle size regime. Particle size analysis of these radioactive slurries down in this smaller range was not previously achievable—making this technology far superior than the traditional methods used. Successful acquisition of this data, in conjunction with other characterization analyses, provides important information that can be used in the myriad of potential radioactive waste management alternatives.

  2. Neutron Diffraction Studies of Carbonate Apatite

    NASA Astrophysics Data System (ADS)

    Moghaddam, Hadi Y.; Leventouri, Theodora; Chakoumakos, Bryan C.

    1998-11-01

    Moghaddam H.Y., Leventouri Th.* (Dept. of Physics & Alloy Research Center, Florida Atlantic Univ.) Chakoumakos B.C. (Solid State Division, Oak Ridge National Lab.**,kou@ornl.gov) We report Rietveld structural refinements of neutron diffraction data of a highly crystalline, single-phase natural carbonate apatite,(francolite of Epirus, Greece), in order to elucidate the details of carbonate substitution in the apatites. The composition is Ca9.56Na0.38Mg0.08(PO4)4.82(CO3)0.946(SO4)0.2F2.34, as determined by electron microprobe analysis. We report refinements of data for the native francolite as a function of temperature between 296K and 10K after the material had been heated at 750 °C to drive off adsorbed water and CO2. The neutron diffractioii@data were collected using a wavelength 1.0912 A on the HB4 high resolution powder diffractometer at the High Flux Isotope Reactor at Oak Ridge National Laboratory. Analysis of the temperature dependence of the anisotropic displacement parameters can reveal the contribution from the temperature independent static positional disorder. Difference displacement parameters evaluated along various bonding directions are being used to describe the mechanics and dynamics of the carbonate for phosphate substitution.*Supported by a SURA-ORNL Summer Cooperative Research Program 1998.**Supported by the Division of Materials Sciences,U.S. D.O.E. (contract DE-AC05-96OR22464 with Lockheed Martin Energy Research Corporation).

  3. Sub-wavelength optical diffraction and photoacoustic metrologies for the characterisation of nanoimprinted structures

    NASA Astrophysics Data System (ADS)

    Kehoe, T.; Bryner, J.; Reboud, V.; Kehagias, N.; Landis, S.; Gourgon, C.; Vollmann, J.; Dual, J.; Sotomayor Torres, C. M.

    2008-03-01

    We report on the use of two original techniques for the quality evaluation of nanoimprint lithography with 50 nm feature size: sub-wavelength blazed diffraction gratings and photoacoustic metrology. Sub-wavelength diffraction has been used to characterise nanoscale structures by studying the diffraction patterns of visible wavelengths of light from gratings which are made up of features below the diffraction limit. Diffraction efficiencies of the diffracted orders are related to the nanoscale line-widths, heights and defects of the gratings. A stamp of a sub-wavelength blazed grating was fabricated by electron beam lithography and reactive ion etching in silicon and imprinted by NIL with different tools. Measured diffraction efficiencies agree with those from finite difference time domain simulations and we demonstrated the possibility to distinguish diffraction patterns from successfully imprinted gratings and those with a defect. The photoacoustic method has been used for the first time to study nanoimprint polymers. Signals were obtained from the top and bottom interfaces of polymer layers with aluminium and silicon, respectively, and thicknesses calculated from the time of flight of the acoustic wave and modelling physical parameters of the polymers, agree well with those measured by profilometry.

  4. Tolerance analysis of multilayer diffractive optics based on polychromatic integral diffraction efficiency.

    PubMed

    Mao, Shan; Cui, Qingfeng; Piao, Mingxu

    2015-11-10

    Multilayer diffractive optical elements (MLDOEs) can achieve high diffraction efficiency for broadband wavelength. Polychromatic integral diffraction efficiency (PIDE) is the key concern for evaluating diffraction efficiency over the waveband. The modulation transfer function of a hybrid refractive-diffractive optical system is directly affected by the PIDE. The relationship between PIDE and continuous manufacturing errors for microstructure heights and periodic widths of MLDOEs is studied theoretically in this paper, and an example of MLDOEs is discussed in the visible waveband. The analysis results can be used for manufacturing error control in microstructure heights and periodic widths. PMID:26560782

  5. The relationship between physical activity and sleep from mid adolescence to early adulthood. A systematic review of methodological approaches and meta-analysis.

    PubMed

    Lang, Christin; Kalak, Nadeem; Brand, Serge; Holsboer-Trachsler, Edith; Pühse, Uwe; Gerber, Markus

    2016-08-01

    Physical activity (PA) is considered an effective, non-pharmacological approach to improve sleep. However, the accurate measurement of PA and sleep among adolescents is fraught with challenges. Additionally, comparing the results of different studies is often difficult due to the diversity of assessment tools, analyses and data reporting procedures used. While previous reviews have considered variables that may confound this relationship, this systematic review examines the variations in measurement methods. Based on this overview, a meta-analysis was performed to assess possible influences of the various approaches on effect sizes. Twenty-one studies were included in the systematic review, of which 12 were appropriate for meta-analysis. For this, four subgroups were formed: subjective PA and subjective sleep, objective PA and subjective sleep, subjective PA and objective sleep, and objective PA and objective sleep. The majority of studies used subjective measures, often with unknown reliability or validity. Few studies employed objective tools to measure sleep. The results suggest that adolescents with higher subjective and objective PA are more likely to experience good sleep subjectively and objectively. More studies employing subjective and objective measures for both PA and sleep are needed. Researchers should take into account several assessment factors unique to the adolescent population. PMID:26447947

  6. [Membranes structure and physical and mechanical erythrocytes properties in the early period of traumatic brain injury caused by less-lethal firearms].

    PubMed

    Gaĭdash, A A; Ivchenko, E V; Levichev, V V; Denisov, A V

    2014-04-01

    The dynamics of erythrocytes properties in the acute phase of traumatic brain injury caused by less-lethal firearms has been studied by the methods of atomic force and morphometry. The experiments have been performed on sheep by a Makarych pistol single shot at the parietooccipital area. It has been established that under the influence of the shock waves the erythrocyte disks and transmembrane liquid oscillatory fluctuations (flicker) are increased. The fluctuations are rapidly attenuated and the shock waves energy is accepted by cytoplasmic membranes lipoproteids. As a result the interface tlipid-protein, phase transitions are hastened. The membranes undergo heterogeneous structural, physical and mechanical transformations the character of which is determined by the phase transitions direction. In the spots of phospolipid liquid clusters accumulation the fluidity is increased and marks caused by membranes lamination and spreading appear. In the spots of phospholipids solid phase the surfaces become hydrophobic and marks caused by membranes local embrittlement and fragility appear. The transmembrane fluid hydrodynamic flows heterogeneity is increased due to deformation processes irregular spreading. The flows acceleration causes the hydrodynamic ruptures-like defects. The flows deceleration results in depressions evolving through the mechanism of creeping erosions. PMID:25051784

  7. Transmittance analysis of diffraction phase grating.

    PubMed

    Jing, Xufeng; Jin, Yunxia

    2011-03-20

    In order to accurately analyze and design the transmittance characteristic of a diffraction phase grating, the validity of both the scalar diffraction theory and the effective medium theory is quantitatively evaluated by the comparison of diffraction efficiencies predicted from both simplified theories to exact results calculated by the rigorous vector electromagnetic theory. The effect of surface profile parameters, including the normalized period, the normalized depth, and the fill factor for the precision of the simplified methods is determined at normal incidence. It is found that, in general, when the normalized period is more than four wavelengths of the incident light, the scalar diffraction theory is useful to estimate the transmittance of the phase grating. When the fill factor approaches 0.5, the error of the scalar method is minimized, and the scalar theory is accurate even at the grating period of two wavelengths. The transmittance characteristic as a function of the normalized period is strongly influenced by the grating duty cycle, but the diffraction performance on the normalized depth is independent of the fill factor of the grating. Additionally, the effective medium theory is accurate for evaluating the diffraction efficiency within an error of less than around 1% when no higher-order diffraction waves appear and only the zero-order waves exist. The precision of the effective medium theory for calculating transmittance properties as a function of the normalized period, the normalized groove depth, and the polarization state of incident light is insensitive to the fill factor of the phase grating. PMID:21460923

  8. Chromatic confocal microscopy using staircase diffractive surface.

    PubMed

    Rayer, Mathieu; Mansfield, Daniel

    2014-08-10

    A chromatic confocal microscope (CCM) is a high-dynamic-range noncontact distance measurement sensor; it is based on a hyperchromatic lens. The vast majority of commercial CCMs use refractive-based chromatic dispersion to chromatically code the optical axis. This approach significantly limits the range of applications and performance of the CCM. In order to be a suitable alternative to a laser triangulation gauge and laser encoder, the performance of the CCM must be improved. In this paper, it is shown how hybrid aspheric diffractive (HAD) lenses can bring the CCM to its full potential by increasing the dynamic range by a factor of 2 and the resolution by a factor of 5 while passively athermizing and increasing the light throughput efficiency of the optical head [M. Rayer, U.S. patent 1122052.2 (2011)]. The only commercially suitable manufacturing process is single-point diamond turning. However, the optical power carried by the diffractive side of a hybrid aspheric diffractive lens is limited by the manufacturing process. A theoretical study of manufacturing losses has revealed that the HAD configuration with the highest diffraction efficiency is for a staircase diffractive surface (SDS). SDS lenses have the potential to reduce light losses associated with manufacturing limits by a factor of 5 without increasing surface roughness, allowing scalar diffraction-limited optical design with a diffractive element. PMID:25320920

  9. Diffraction enhanced x-ray imaging

    SciTech Connect

    Thomlinson, W.; Zhong, Z.; Chapman, D.; Johnston, R.E.; Sayers, D.

    1997-09-01

    Diffraction enhanced imaging (DEI) is a new x-ray radiographic imaging modality using synchrotron x-rays which produces images of thick absorbing objects that are almost completely free of scatter. They show dramatically improved contrast over standard imaging applied to the same phantoms. The contrast is based not only on attenuation but also the refraction and diffraction properties of the sample. The diffraction component and the apparent absorption component (absorption plus extinction contrast) can each be determined independently. This imaging method may improve the image quality for medical applications such as mammography.

  10. 3D printed diffractive terahertz lenses.

    PubMed

    Furlan, Walter D; Ferrando, Vicente; Monsoriu, Juan A; Zagrajek, Przemysław; Czerwińska, Elżbieta; Szustakowski, Mieczysław

    2016-04-15

    A 3D printer was used to realize custom-made diffractive THz lenses. After testing several materials, phase binary lenses with periodic and aperiodic radial profiles were designed and constructed in polyamide material to work at 0.625 THz. The nonconventional focusing properties of such lenses were assessed by computing and measuring their axial point spread function (PSF). Our results demonstrate that inexpensive 3D printed THz diffractive lenses can be reliably used in focusing and imaging THz systems. Diffractive THz lenses with unprecedented features, such as extended depth of focus or bifocalization, have been demonstrated. PMID:27082335

  11. New diffractive results from the Tevatron

    SciTech Connect

    Gallinaro, Michele; /Rockefeller U.

    2005-05-01

    Experimental results in diffractive processes are summarized and a few notable characteristics described in terms of Quantum Chromodynamics. Exclusive dijet production is used to establish a benchmark for future experiments in the quest for diffractive Higgs production at the Large Hadron Collider. Using new data from the Tevatron and dedicated diffractive triggers, no excess over a smooth falling distribution for exclusive dijet events could be found. Stringent upper limits on the exclusive dijet production cross section are presented. The quark/gluon composition of dijet final states is used to provide additional hints on exclusive dijet production.

  12. A scattering approach to sea wave diffraction

    NASA Astrophysics Data System (ADS)

    Corradini, M. L.; Garbuglia, M.; Maponi, P.; Ruggeri, M.

    2016-06-01

    This paper intends to show a model for the diffraction of sea waves approaching an OWC device, which converts the sea waves motion into mechanical energy and then electrical energy. This is a preliminary study to the optimisation of the device, in fact the computation of sea waves diffraction around the device allows the estimation of the sea waves energy which enters into the device. The computation of the diffraction phenomenon is the result of a sea waves scattering problem, solved with an integral equation method.

  13. Strain Determination Using Electron Backscatter Diffraction

    SciTech Connect

    Krause, M.; Graff, A.; Altmann, F.

    2010-11-24

    In the present paper we demonstrate the use of electron backscatter diffraction (EBSD) for high resolution elastic strain determination. Here, we focus on analysis methods based on determination of small shifts in EBSD pattern with respect to a reference pattern using cross-correlation algorithms. Additionally we highlight the excellent spatial and depth resolution of EBSD and introduce the use of simulated diffraction patterns based on dynamical diffraction theory for sensitivity estimation. Moreover the potential of EBSD for strain analysis of strained thin films with particular emphasis on appropriate target preparation which respect to occurring lattice defects is demonstrated.

  14. What periodicities can be found in diffraction patterns of quasicrystals?

    PubMed

    Wolny, Janusz; Kozakowski, Bartlomiej; Kuczera, Pawel; Pytlik, Lucjan; Strzalka, Radoslaw

    2014-03-01

    The structure of quasicrystals is aperiodic. Their diffraction patterns, however, can be considered periodic. They are composed solely of series of peaks which exhibit a fully periodic arrangement in reciprocal space. Furthermore, the peak intensities in each series define the so-called `envelope function'. A Fourier transform of the envelope function gives an average unit cell, whose definition is based on the statistical distribution of atomic coordinates in physical space. If such a distribution is lifted to higher-dimensional space, it becomes the so-called atomic surface - the most fundamental feature of higher-dimensional analysis. PMID:24572319

  15. Elementary amplitudes in the multiple diffraction theory reexamined

    SciTech Connect

    Martini, A.F.; Menon, M.J.; Thober, D.S.

    1996-08-01

    We show that, in the context of Glauber{close_quote}s multiple diffraction theory, the square of the correction factor introduced by Bourrely, Soffer, and Wu in a double-pole form factor parametrization, may be interpreted as an elementary (parton-parton) amplitude. The condition concerning the existence of a well-defined Fourier transform is demonstrated, and it is shown that the corresponding profile function comes from an ordinary transform (Bessel function) plus a generalized transform ({delta} distribution). Comparisons with a modified parametrization and results from a model-independent analysis are also presented and discussed. {copyright} {ital 1996 The American Physical Society.}

  16. Electron paths, tunnelling, and diffraction in the spacetime algebra

    NASA Astrophysics Data System (ADS)

    Gull, Stephen; Lasenby, Anthony; Doran, Chris

    1993-10-01

    This paper employs the ideas of geometric algebra to investigate the physical content of Dirac's electron theory. The basis is Hestenes' discovery of the geometric significance of the Dirac spinor, which now represents a Lorentz transformation in spacetime. This transformation specifies a definite velocity, which might be interpreted as that of a real electron. Taken literally, this velocity yields predictions of tunnelling times through potential barriers, and defines streamlines in spacetime that would correspond to electron paths. We also present a general, first-order diffraction theory for electromagnetic and Dirac waves. We conclude with a critical appraisal of the Dirac theory.

  17. Waveguide properties recovered from shallow diffractions in common offset GPR

    NASA Astrophysics Data System (ADS)

    Strobach, Elmar; Harris, Brett D.; Dupuis, J. Christian; Kepic, Anton W.

    2013-01-01

    Near-surface heterogeneities produce diffractions in common offset ground-penetrating radar (GPR) data from the Gnangara Groundwater Mound, north of Perth, Western Australia. These diffracted wavefields can be enhanced and show a dispersion pattern if they propagate along a waveguide caused by a low velocity surface layer, such as moist sand on top of dry sand. Until now, GPR waveguide dispersion has been analyzed and inverted using common midpoint data. Using numerical modeling, we demonstrate that the same dispersion information can also be recovered from a diffracted electromagnetic wavefield recorded with common offset geometry. Frequency-slowness analysis of shallow diffractions in common offset GPR field data reveals high resolution dispersion curves. Inverting picked dispersion maxima to modeled curves (i.e., modal wave propagation in waveguide layer) allows estimation of waveguide height and velocities of waveguide and the underlying material. Data analysis in the frequency-wavenumber domain provides an alternative technique for extracting dispersion curves. Preliminary results validate this approach, which could be favorable in large-scale applications due to minimal processing requirement and inherent yet adjustable spatial averaging. The differences between waveguide parameters recovered from two surveys appear to be consistent with seasonal changes in moisture content and lateral changes due to variations in depositional environment. Our approach presents a new method to quantify the shallow dielectric permittivity structure of the subsurface from common offset gathers—the most commonly acquired type of GPR data. Potential applications of this method include estimation of shallow moisture distribution, early target identification for unexploded ordnance (UXO) detection, concrete slab characterization, pedological investigations, or planetary exploration.

  18. X-Ray Diffractive Optics

    NASA Technical Reports Server (NTRS)

    Dennis, Brian; Li, Mary; Skinner, Gerald

    2013-01-01

    X-ray optics were fabricated with the capability of imaging solar x-ray sources with better than 0.1 arcsecond angular resolution, over an order of magnitude finer than is currently possible. Such images would provide a new window into the little-understood energy release and particle acceleration regions in solar flares. They constitute one of the most promising ways to probe these regions in the solar atmosphere with the sensitivity and angular resolution needed to better understand the physical processes involved. A circular slit structure with widths as fine as 0.85 micron etched in a silicon wafer 8 microns thick forms a phase zone plate version of a Fresnel lens capable of focusing approx. =.6 keV x-rays. The focal length of the 3-cm diameter lenses is 100 microns, and the angular resolution capability is better than 0.1 arcsecond. Such phase zone plates were fabricated in Goddard fs Detector Development Lab. (DDL) and tested at the Goddard 600-microns x-ray test facility. The test data verified that the desired angular resolution and throughput efficiency were achieved.

  19. Mesoscale Diffractive Photonics in Geosciences

    NASA Astrophysics Data System (ADS)

    Minin, I. V.; Minin, O. V.

    2016-06-01

    The scattered light by various dielectric particles in atmosphere give information about the type of molecules and particles and their location, which are important to definition of propagation limitations through atmospheric and space weather variations, crisis communications, etc. Although these investigations explain far field properties of disturbed radiations, the solution of the physical problem requires simulations of the interactions in near-field. It has been shown that strongly localized EM field near the surface of single dielectric particle may be form by non-spherical and non-symmetrical mesoscale particles both as in transmitting as in reflection mode. It was also shown that the main lobe is narrower in case of 3 cube chain than single cube in far field, but there are many side-scattering lobes. It was mentioned that unique advantages provided by mesoscale dielectric photonic crystal based particles with three spatial dimensions of arbitrary shape allow developing a new types of micro/nano-probes with subwavelength resolution for ultra compact spectrometer-free sensor for on board a spacecraft or a plane.

  20. Development of splitting convergent beam electron diffraction (SCBED).

    PubMed

    Houdellier, Florent; Röder, Falk; Snoeck, Etienne

    2015-12-01

    Using a combination of condenser electrostatic biprism with dedicated electron optic conditions for sample illumination, we were able to split a convergent beam electron probe focused on the sample in two half focused probes without introducing any tilt between them. As a consequence, a combined convergent beam electron diffraction pattern is obtained in the back focal plane of the objective lens arising from two different sample areas, which could be analyzed in a single pattern. This splitting convergent beam electron diffraction (SCBED) pattern has been tested first on a well-characterized test sample of Si/SiGe multilayers epitaxially grown on a Si substrate. The SCBED pattern contains information from the strained area, which exhibits HOLZ lines broadening induced by surface relaxation, with fine HOLZ lines observed in the unstrained reference part of the sample. These patterns have been analyzed quantitatively using both parts of the SCBED transmitted disk. The fine HOLZ line positions are used to determine the precise acceleration voltage of the microscope while the perturbed HOLZ rocking curves in the stained area are compared to dynamical simulated ones. The combination of these two information leads to a precise evaluation of the sample strain state. Finally, several SCBED setups are proposed to tackle fundamental physics questions as well as applied materials science ones and demonstrate how SCBED has the potential to greatly expand the range of applications of electron diffraction and electron holography. PMID:26319180

  1. The impact of novel 3D diffraction optics development

    NASA Astrophysics Data System (ADS)

    Firsov, Alexander; Brzhezinskaya, Maria; Loechel, Heike; Siewert, Frank; Erko, Alexei

    2013-05-01

    Dedicated diffractive VUV- and X-ray optical elements are essential for future developments in synchrotron instrumentation and methods like e.g. time-resolved spectroscopy. The quality of optical components like gratings or diffractive focusing elements matters directly to the results achievable. On the other hand the availability of such optical components is very limited at present. In this contribution we report on the development of new methods of time-resolved x-ray spectroscopy based on novel 3D diffractive optical elements (DOE) with a unique combination of properties. Such optical elements are of highest interest for application in modern synchrotron facilities like Free Electron Lasers (FELs) as well as for laboratory facilities with high harmonic generators (HHG). The project includes theoretical work as well as the development of a dedicated technology, including metrology, to manufacture such type of optics for applications in atomic, molecular and condensed matter physics. The here discussed type of optics was successfully implemented for soft-X-ray-application at the femto-second-slicing beamline at BESSY II storage ring of the Helmholtz Zentrum Berlin. DOE are expected to be important components in beamlines at upcoming new high brilliance X-ray sources such as FELs. The application of DOE`s allows to reduce the number of optical elements in a beamline. Thus allow to provide the highest possible transmission and flux as well as preserving the unique properties of FEĹs, like wave-front and coherence.

  2. Scalar limitations of diffractive optical elements

    NASA Technical Reports Server (NTRS)

    Johnson, Eric G.; Hochmuth, Diane; Moharam, M. G.; Pommet, Drew

    1993-01-01

    In this paper, scalar limitations of diffractive optic components are investigated using coupled wave analyses. Results are presented for linear phase gratings and fanout devices. In addition, a parametric curve is given which correlates feature size with scalar performance.

  3. Optical diffraction by inhomogeneous volume objects

    NASA Astrophysics Data System (ADS)

    Forte, Gustavo; Lencina, Alberto; Tebaldi, Myrian; Bolognini, Nestor

    2008-08-01

    Electromagnetic waves propagation research in volume media increases considerably in the last years. The study evolved from thick hologram gratings, Bragg and Raman-Nath diffraction regimes up to current research in photonics materials. Usually differential methods are employed to account for the light transmitted for volume media. In our proposal, we develop a simple and versatile integral method to calculate the diffracted field provided the media refractive index has low variations in a wavelength scale. In fact, starting from first principles, we obtain a modified version of the Fresnel propagator of the scalar diffraction theory. Our method is valid for some kind of magnetic, dielectric and absorbent inhomogeneous media. In particular, for TE (TM) fields, we can study media where the permittivity (permeability) gradient is perpendicular to the electric (magnetic) field and its permeability (permittivity) is constant. To validate the approach, we applied it to (in) homogeneous media having well known diffraction properties.

  4. High-diffraction-efficiency pseudorandom encoding.

    PubMed

    Yang, Y; Stark, H; Gurkan, D; Lawson, C L; Cohn, R W

    2000-02-01

    Pseudorandom encoding (PRE) is a statistics-based procedure in which a pure-phase spatial light modulator (SLM) can yield, on the average, the prescribed diffraction pattern specified by the user. We seek to combine PRE with the optimization of an aperture-based target function. The target function is a fully complex input transmittance, unrealizable by a phase-only SLM, that generates a prescribed light intensity. The optimization is done to increase the diffraction efficiency of the overall process. We compare three optimization methods-Monte Carlo simulation, a genetic algorithm, and a gradient search-for maximizing the diffraction efficiency of a spot-array generator. Calculated solutions are then encoded by PRE, and the resulting diffraction patterns are computer simulated. Details on the complexity of each procedure are furnished, as well as comparisons on the quality, such as uniformity of the output spot array. PMID:10680630

  5. Tension in the LHC diffractive data?

    SciTech Connect

    Gotsman, Errol

    2015-04-10

    I discuss the LHC diffractive data, and compare it to predicted energy behaviour of various models. I suggest that the so called 'tension' between the experimental results, maybe due to the different Monte Carlo programs used.

  6. An Electronic Analog of the Diffraction Grating.

    ERIC Educational Resources Information Center

    MacLeod, A. M.

    1978-01-01

    Gives an outline description of electronic circuitry which is analogous to the optical diffraction grating or to crystals used in the Bragg reflection of X-rays or electron waves, and explains how to use it. (Author/GA)

  7. Electron Diffraction of Superfluid Helium Droplets

    PubMed Central

    2014-01-01

    We present experimental results of electron diffraction of superfluid helium droplets and droplets doped with phthalocyanine gallium chloride and discuss the possibility of performing the same experiment with a laser aligned sample. The diffraction profile of pure droplets demonstrates dependence on the nozzle temperature, that is, on the average size of the droplets. Larger clusters demonstrate faster decay with increasing momentum transfer, whereas smaller clusters converge to isolated gas phase molecules at source temperatures of 18 K and higher. Electron diffraction of doped droplets shows similar modified molecular scattering intensity as that of the corresponding gas phase molecules. On the basis of fittings of the scattering profile, the number of remaining helium atoms of the doped droplets is estimated to be on the order of hundreds. This result offers guidance in assessing the possibility of electron diffraction from laser aligned molecules doped in superfluid helium droplets. PMID:24920997

  8. Diffraction-limited ultrabroadband terahertz spectroscopy

    PubMed Central

    Baillergeau, M.; Maussang, K.; Nirrengarten, T.; Palomo, J.; Li, L. H.; Linfield, E. H.; Davies, A. G.; Dhillon, S.; Tignon, J.; Mangeney, J.

    2016-01-01

    Diffraction is the ultimate limit at which details of objects can be resolved in conventional optical spectroscopy and imaging systems. In the THz spectral range, spectroscopy systems increasingly rely on ultra-broadband radiation (extending over more 5 octaves) making a great challenge to reach resolution limited by diffraction. Here, we propose an original easy-to-implement wavefront manipulation concept to achieve ultrabroadband THz spectroscopy system with diffraction-limited resolution. Applying this concept to a large-area photoconductive emitter, we demonstrate diffraction-limited ultra-broadband spectroscopy system up to 14.5 THz with a dynamic range of 103. The strong focusing of ultrabroadband THz radiation provided by our approach is essential for investigating single micrometer-scale objects such as graphene flakes or living cells, and besides for achieving intense ultra-broadband THz electric fields. PMID:27142959

  9. Eyeglass. 1. Very large aperture diffractive telescopes.

    PubMed

    Hyde, R A

    1999-07-01

    The Eyeglass is a very large aperture (25-100-m) space telescope consisting of two distinct spacecraft, separated in space by several kilometers. A diffractive lens provides the telescope s large aperture, and a separate, much smaller, space telescope serves as its mobile eyepiece. Use of a transmissive diffractive lens solves two basic problems associated with very large aperture space telescopes; it is inherently launchable (lightweight, packagable, and deployable) it and virtually eliminates the traditional, very tight surface shape tolerances faced by reflecting apertures. The potential drawback to use of a diffractive primary (very narrow spectral bandwidth) is eliminated by corrective optics in the telescope s eyepiece; the Eyeglass can provide diffraction-limited imaging with either single-band (Deltalambda/lambda approximately 0.1), multiband, or continuous spectral coverage. PMID:18323902

  10. Electron backscatter diffraction: applications for nuclear materials.

    PubMed

    Medevielle; Hugon; Dugne

    1999-09-01

    The diffraction of electrons was first observed in 1928 by Kikuchi. The phenomenon results in the formation of characteristic diagrams of the crystalline lattice and the orientation of the phase. Backscattered electrons are diffracted by the different crystallographic planes (hkl) according to the Bragg angle thetab. These describe, by symmetry, two cones of axes normal to the diffracting plane. Information is collected on a phosphor screen, leading to the acquisition of a diffraction pattern called a Kikuchi diagram. Several improvements now give a wide range of applications such as phase identification (carbides or complex compounds in a (U,Zr,O) structure), analysis of materials interfaces (ZrO2/UO2), as well as solidification studies and local texture determination (molybdenum sheets). In these applications, EBSD, as a type of quantitative metallography, is a powerful tool. PMID:10460689

  11. Diffraction for a Neumann boundary condition

    SciTech Connect

    Lafitte, O.

    1997-11-01

    Let 0 be a bounded open set in R{sup n} and P be a constant coefficient operator of order 2 in R{sup n} x R{sub t} such that (P, {Omega}{sup c}) admits a strictly diffractive point. We calculate in this paper the principal symbol of the operator K transforming {partial_derivative}{sub n}u into u/{sub {partial_derivative}{Omega}} for a solution u of Pu = 0 in the neighborhood of a strictly diffractive point {rho}{sub 0} for (P, {Omega}{sup c}). We deduce from this calculation the principal symbol of the wave diffracted by a strictly convex analytic obstacle with a Neumann boundary condition. This result is used to calculate the electromagnetic wave diffracted by a perfectly conducting body. 7 refs., 2 figs.

  12. Diffraction-limited ultrabroadband terahertz spectroscopy

    NASA Astrophysics Data System (ADS)

    Baillergeau, M.; Maussang, K.; Nirrengarten, T.; Palomo, J.; Li, L. H.; Linfield, E. H.; Davies, A. G.; Dhillon, S.; Tignon, J.; Mangeney, J.

    2016-05-01

    Diffraction is the ultimate limit at which details of objects can be resolved in conventional optical spectroscopy and imaging systems. In the THz spectral range, spectroscopy systems increasingly rely on ultra-broadband radiation (extending over more 5 octaves) making a great challenge to reach resolution limited by diffraction. Here, we propose an original easy-to-implement wavefront manipulation concept to achieve ultrabroadband THz spectroscopy system with diffraction-limited resolution. Applying this concept to a large-area photoconductive emitter, we demonstrate diffraction-limited ultra-broadband spectroscopy system up to 14.5 THz with a dynamic range of 103. The strong focusing of ultrabroadband THz radiation provided by our approach is essential for investigating single micrometer-scale objects such as graphene flakes or living cells, and besides for achieving intense ultra-broadband THz electric fields.

  13. Dual-domain point diffraction interferometer.

    PubMed

    Naulleau, P P; Goldberg, K A

    1999-06-01

    The phase-shifting point diffraction interferometer has recently been developed and implemented at Lawrence Berkeley National Laboratory to meet the significant metrology challenge of characterizing extreme ultraviolet projection lithography systems. Here we present a refined version of this interferometer that overcomes the original design's susceptibility to noise attributed to scattered light. The theory of the new hybrid spatial- and temporal-domain (dual-domain) point diffraction interferometer is described in detail and experimental results are presented. PMID:18319953

  14. Breakdown of QCD factorization in hard diffraction

    NASA Astrophysics Data System (ADS)

    Kopeliovich, B. Z.

    2016-07-01

    Factorization of short- and long-distance interactions is severely broken in hard diffractive hadronic collisions. Interaction with the spectator partons leads to an interplay between soft and hard scales, which results in a leading twist behavior of the cross section, on the contrary to the higher twist predicted by factorization. This feature is explicitly demonstrated for diffractive radiation of abelian (Drell-Yan, gauge bosons, Higgs) and non-abelian (heavy flavors) particles.

  15. Nuclear diffractive structure functions at high energies

    SciTech Connect

    Marquet,C.; Kowalski, H.; Lappi, T.; Venugopalan, R.

    2008-08-08

    A future high-energy electron-ion collider would explore the non-linear weakly-coupled regime of QCD, and test the Color Glass Condensate (CGC) approach to high-energy scattering. Hard diffraction in deep inelastic scattering off nuclei will provide many fundamental measurements. In this work, the nuclear diffractive structure function F{sub 2,A}{sup D} is predicted in the CGC framework, and the features of nuclear enhancement and suppression are discussed.

  16. Simulating interference and diffraction in instructional laboratories

    NASA Astrophysics Data System (ADS)

    Maurer, L.

    2013-03-01

    Studieshave shown that standard lectures and instructional laboratory experiments are not effective at teaching interference and diffraction. In response, the author created an interactive computer program that simulates interference and diffraction effects using the finite difference time domain method. The software allows students to easily control, visualize and quantitatively measure the effects. Students collected data from simulations as part of their laboratory exercise, and they performed well on a subsequent quiz, showing promise for this approach.

  17. Diffraction pattern of gratings with erosion

    NASA Astrophysics Data System (ADS)

    Olivares-Pérez, Arturo; Fuentes-Tapia, Israel

    2015-03-01

    We present a theoretical study of amplitude diffraction gratings using computer simulating, which consists of a random sampling of points on the image grating to determine the points to be plotted and the points to remove, to simulate erosion in amplitude on the grating. We show their behavior in the diffraction patterns and the induced noise by limiting the number of points that representing the image of the eroded gratings and their symmetry.

  18. Observation of hard diffraction with CMS

    SciTech Connect

    Obertino, M. M.

    2009-03-23

    Diffraction with a hard scale can be observed in the first LHC data. We present studies of single diffractive W-boson production (pp{yields}Xp, with X including a W boson) and of {upsilon} photoproduction (pp{yields}{upsilon}p, with {upsilon}{yields}{mu}{sup +}{mu}{sup -}). The feasibility of observing these processes with the CMS detector using the first 100 pb{sup -1} of collected integrated luminosity for single interactions is discussed.

  19. A-DNA and B-DNA: Comparing Their Historical X-Ray Fiber Diffraction Images

    ERIC Educational Resources Information Center

    Lucas, Amand A.

    2008-01-01

    A-DNA and B-DNA are two secondary molecular conformations (among other allomorphs) that double-stranded DNA drawn into a fiber can assume, depending on the relative water content and other chemical parameters of the fiber. They were the first two forms to be observed by X-ray fiber diffraction in the early 1950s, respectively by Wilkins and…

  20. Preventing Early Learning Failure.

    ERIC Educational Resources Information Center

    Sornson, Bob, Ed.

    Noting that thousands of young children with the capacity to experience school success do not because they are unprepared for school learning activities, have experienced physical or emotional setbacks that cause them to be at risk for early learning failure, have never experienced limits on their behavior, or have mild sensory or motor deficits,…