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Sample records for charge study children

  1. Immune Dysfunction in Children with CHARGE Syndrome: A Cross-Sectional Study

    PubMed Central

    van der Burg, Mirjam; la Bastide-van Gemert, Sacha; Hogendorf, Lianne A.; van Ravenswaaij-Arts, Conny M. A.; Schölvinck, Elisabeth H.

    2015-01-01

    CHARGE syndrome is a variable, multiple congenital malformation syndrome. Patients with CHARGE syndrome have frequent infections that are presumed to be due to anatomical anomalies of the craniofacial region and upper airway, and cranial nerve problems resulting in swallowing difficulties and aspiration. The possible contribution of immunological abnormalities to these infections has not been systematically studied even though immune deficiencies have been described in patients with 22q11.2 deletion syndrome, a condition which shares remarkable clinical overlap with CHARGE syndrome. We assessed the frequency and nature of immune dysfunction in 24 children with genetically proven CHARGE syndrome. All patients, or their parents, completed a questionnaire on infectious history. Their immune system was extensively assessed through full blood counts, immunoglobulin levels, lymphocyte subpopulations, peripheral B- and T-cell differentiation, T-receptor excision circle (TREC) analysis, T-cell function, and vaccination responses. All CHARGE patients had a history of infections (often frequent), mainly otitis media and pneumonia, leading to frequent use of antibiotics and to hospital admissions. Decreased T-cell numbers were found in 12 (50%) patients, presumably caused by insufficient thymic output since TREC amounts were also diminished in CHARGE patients. Despite normal peripheral B-cell differentiation and immunoglobulin production in all patients, 83% of patients had insufficient antibody titers to one or more early childhood vaccinations. Based on our results, we recommend immunological evaluation of CHARGE patients with recurrent infections. PMID:26544072

  2. Asthma and Allergies in Children With Autism Spectrum Disorders: Results From the CHARGE Study.

    PubMed

    Lyall, Kristen; Van de Water, Judy; Ashwood, Paul; Hertz-Picciotto, Irva

    2015-10-01

    Immune aberrations are often noted in children with autism spectrum disorder (ASD), but whether asthma and allergy are related to ASD is not well defined. This study examined asthma and allergies in association with ASD and phenotypic subsets. Participants were 560 children with confirmed ASD and 391 typically developing children from the CHildhood Autism Risks from Genetics and the Environment study. Maternally reported child asthma and allergy was compared between cases and controls, and in association with cognitive and behavioral test scores. Prevalence of asthma and overall allergies did not differ between cases and controls, but overall allergy in children with ASD was associated with higher stereotypy scores as measured by the Aberrant Behavior Checklist. In addition, reported food allergies were significantly associated with ASD (adjusted odds ratio = 2.23, 95% confidence interval 1.28, 3.89). Our results suggest food allergies and sensitivities may be more common in children with ASD, and that these issues may correlate with other behaviors.

  3. Physical Education and Children with CHARGE Syndrome: Research to Practice

    ERIC Educational Resources Information Center

    Lieberman, Lauren J.; Haibach, Pamela; Schedlin, Haley

    2012-01-01

    Introduction: Children with CHARGE syndrome often experience significantly delayed motor development, which affects their performance in many motor skills and physical activities. The purpose of this study was to determine the status of physical education provided to children with CHARGE syndrome. There were five main areas of focus: (1) physical…

  4. Characteristics and Development of Children with CHARGE Association/Syndrome

    ERIC Educational Resources Information Center

    Salem-Hartshorne, Nancy; Jacob, Susan

    2004-01-01

    CHARGE association/syndrome refers to a group of congenital anomalies occurring together more often than chance. Parents of children with CHARGE were surveyed and asked to indicate whether their child had various features commonly found among individuals with CHARGE (e.g., vision or hearing impairment) and to complete an adaptive behavior scale…

  5. Characteristics And Development Of Children With CHARGE Association-Syndrome

    ERIC Educational Resources Information Center

    Salem-Hartshorne, Nancy; Jacob, Susan

    2004-01-01

    CHARGE association-syndrome refers to a group of congenital anomalies occurring together more often than chance. Parents of children with CHARGE were surveyed and asked to indicate whether their child had various features commonly found among individuals with CHARGE (e.g., vision or hearing impairment) and to complete an adaptive behavior scale…

  6. Communication in the Early Stage of Language Development in Children with CHARGE Syndrome

    ERIC Educational Resources Information Center

    Peltokorpi, Sini; Huttunen, Kerttu

    2008-01-01

    CHARGE syndrome is characterized by multiple physical abnormalities, and impaired vision and hearing. In this pilot study, communication in the early stage of language development in three one- to eight-year-old children with CHARGE syndrome was explored using video recorded free-play interaction sessions and a parental questionnaire. The children…

  7. Who's in Charge of Protecting Children's Health at School? A Report on "America's Largest Unaddressed Children's Health Crisis"

    ERIC Educational Resources Information Center

    Barnett, Claire L.

    2005-01-01

    This report makes the case that no one is in charge of protecting children from harmful environmental exposures at school and recommends steps at the federal and in New York State to begin to address this hidden world. With information gleaned from adult occupational health experts, from new national studies and reports, and from the reports of…

  8. Cochlear implantation in children with "CHARGE syndrome": surgical options and outcomes.

    PubMed

    Ricci, Giampietro; Trabalzini, Franco; Faralli, Mario; D'Ascanio, Luca; Cristi, Cristina; Molini, Egisto

    2014-03-01

    CHARGE syndrome is a rare, polymalformative disease, representing one of the major causes of associated blindness and deafness. Bilateral, severe-profound, sensorineural hearing loss is common in CHARGE children. Aim of this study is to present our results in children with "CHARGE syndrome" submitted to cochlear implantation (CI). The frequency of anatomic anomalies, possible variations in the surgical technique of CI, and the audiological/rehabilitative benefits attained in our patients are reported. we submitted 5 children affected by CHARGE syndrome with profound, bilateral, sensorineural hearing loss to CI. Otoacoustic emissions, auditory brainstem response, acoustic impedance testing, cranial computed tomography and magnetic resonance were carried out preoperatively in all children. CI was performed using the mastoidotomy-posterior tympanotomy approach in two cases, and the suprameatal approach in three children. Infant toddler-meaningful auditory integration scale was used to evaluate kid's audiological performance before and after CI. Intra-operatory findings and postsurgical complications were evaluated. Among our patients, intraoperative anatomical malformations were cochlear hypoplasia (100 %), ossicles malformations (100 %), semicircular canals aplasia (100 %), oval window atresia (60 %), round window atresia (40 %), widening of the aqueduct of the vestibule (20 %), and aberrant course of the facial nerve (20 %). No intra- or postoperative complication was recorded in relation to implant positioning. After a follow-up ranging from 1 to 4.5 years, only 2/5 patients used oral language as the sole mean of communication, 1 started utilizing oral language as the main mean of communication, while 2 patients did not develop any linguistic ability. In conclusion, CI in patients with CHARGE association is feasible and, despite results variability, it should be carried out in CHARGE children with severe hearing loss as soon as possible. Although the selection of a

  9. Balance and Self-Efficacy of Balance in Children with CHARGE Syndrome

    ERIC Educational Resources Information Center

    Haibach, Pamela S.; Lieberman, Lauren J.

    2013-01-01

    Introduction: Balance is a critical component of daily living, because it affects all movements and the ability to function independently. Children with CHARGE syndrome have sensory and motor impairments that could negatively affect their balance and postural control. The purpose of the study presented in this article was to assess the balance and…

  10. Abusive Head Trauma in Young Children: Characteristics and Medical Charges in a Hospitalized Population

    ERIC Educational Resources Information Center

    Ettaro, L.; Berger, R. P.; Songer, T.

    2004-01-01

    Objective: To describe the presenting characteristics, hospital course, and hospital charges associated with hospital admissions for head trauma in young children at a regional pediatric trauma center, and to examine whether these factors differ among abused and non-abused subjects. Method: Comparative case series study involving a retrospective…

  11. Who's in charge of children's environmental health at school?

    PubMed

    Paulson, Jerome; Barnett, Claire

    2010-01-01

    Children spend many hours each week in and around school buildings. Their short- and long-term health outcomes and ability to learn are affected by numerous environmental factors related to the school buildings, the school grounds, the school transportation system, and the use of various products and materials in and around the school. Many school buildings are old, and they-and even newer buildings-can contain multiple environmental health hazards. While some districts self-report they have environmental health policies in place, no independent verification of these policies or their quality exists. Teachers and other staff, but not children who are more vulnerable to hazards than adults, are afforded some protections from hazards by Occupational Safety and Health Administration (OSHA) regulations, by their employment contracts, or through adult occupational health services. Major environmental problems include: indoor air quality, lighting, pests and pesticides, heavy metals and chemical management issues, renovation of occupied buildings, noise, and cleaning processes and products. No agency at the federal or state levels is charged with ensuring children's health and safety in and around school buildings. No systematic means exists for collecting data about exposures which occur in the school setting. Recommendations are made for dealing with issues of data collection, federal actions, state and local actions, and for building the capacity of the Environmental Protection Agency and the Centers for Disease Control and Prevention-designated and funded Pediatric Environmental Health Specialty Units (PEHSU) in responding to and evaluating risks to children's environmental health in schools.

  12. Studying Spacecraft Charging via Numerical Simulations

    NASA Astrophysics Data System (ADS)

    Delzanno, G. L.; Moulton, D.; Meierbachtol, C.; Svyatskiy, D.; Vernon, L.

    2015-12-01

    The electrical charging of spacecraft due to bombarding charged particles can affect their performance and operation. We study this charging using CPIC; a particle-in-cell code specifically designed for studying plasma-material interactions [1]. CPIC is based on multi-block curvilinear meshes, resulting in near-optimal computational performance while maintaining geometric accuracy. Relevant plasma parameters are imported from the SHIELDS framework (currently under development at LANL), which simulates geomagnetic storms and substorms in the Earth's magnetosphere. Simulated spacecraft charging results of representative Van Allen Probe geometries using these plasma parameters will be presented, along with an overview of the code. [1] G.L. Delzanno, E. Camporeale, J.D. Moulton, J.E. Borovsky, E.A. MacDonald, and M.F. Thomsen, "CPIC: A Curvilinear Particle-In-Cell Code for Plasma-Material Interaction Studies," IEEE Trans. Plas. Sci., 41 (12), 3577 (2013).

  13. Cochlear Implants in Children Diagnosed with CHARGE Syndrome

    PubMed Central

    Cardoso, Carolina Costa; Sales de Meneses, Michelle; Silva, Isabella Monteiro de Castro; Alves, Angela Maria Vaccaro Silva

    2013-01-01

    Introduction The CHARGE association (coloboma of the eyes; heart disease; atresia of the choanae; retarded growth and development; genital hypoplasia/genitourinary anomalies; ear anomalies and/or hearing loss) was first described in 1979 by Hall, and among its main features is hearing loss. This study presents a case aiming to establish relationships between performance on Infant Toddler Meaningful Auditory Integration Scale (IT-MAIS) and Meaningful Use of Speech Scales (MUSS) tests and the analysis of hearing and language categories of a patient diagnosed with CHARGE syndrome, before and after cochlear implant (CI) surgery. Case Report A 7-year-old girl was diagnosed with CHARGE. She had severe sensorineural hearing loss and was a prelingual unilateral CI user. We analyzed data from the patient's medical records regarding therapies and video recordings. Results The patient showed positive results in all evaluations after CI. IT-MAIS rose from 5 to 90% following the use of CI. MUSS also rose, from 75 to 72.5%, after use of CI. Classification of Auditory Skills changed from category 1 before use of CI to category 6 after use of CI. Classification of Language Skills changed from category 1 before use of CI to category 3 after use of CI. The CI is an aid but there are many factors in the therapeutic process, and great heterogeneity in individuals diagnosed with CHARGE should be investigated. Conclusion The development of listening and language skills after CI use was demonstrated by IT-MAIS and MUSS tests, and categorization of speech and hearing in this child with a diagnosis of CHARGE syndrome shows that CI can be an effective technological resource to provide information on hearing as one source for language construction. PMID:25992052

  14. Experimental Study of Dust Grain Charging

    NASA Technical Reports Server (NTRS)

    Spann, James F; Venturini, Catherine C.; Comfort, Richard H.; Mian, Abbas M.

    1999-01-01

    The results of an experimental study of the charging mechanisms of micron size dust grains are presented. Individual dust grains are electrodynamically suspended and exposed to an electron beam of known energy and flux, and to far ultraviolet radiation of known wavelength and intensity. Changes in the charge-to-mass ratio of the grain are directly measured as a function of incident beam (electron and/or photon), grain size and composition. Comparisons of our results to theoretical models that predict the grain response are presented.

  15. Studying Charged Particle Optics: An Undergraduate Course

    ERIC Educational Resources Information Center

    Ovalle, V.; Otomar, D. R.; Pereira, J. M.; Ferreira, N.; Pinho, R. R.; Santos A. C. F.

    2008-01-01

    This paper describes some computer-based activities to bring the study of charged particle optics to undergraduate students, to be performed as a part of a one-semester accelerator-based experimental course. The computational simulations were carried out using the commercially available SIMION program. The performance parameters, such as the focal…

  16. Simulation study of pixel detector charge digitization

    NASA Astrophysics Data System (ADS)

    Wang, Fuyue; Nachman, Benjamin; Sciveres, Maurice; Lawrence Berkeley National Laboratory Team

    2017-01-01

    Reconstruction of tracks from nearly overlapping particles, called Tracking in Dense Environments (TIDE), is an increasingly important component of many physics analyses at the Large Hadron Collider as signatures involving highly boosted jets are investigated. TIDE makes use of the charge distribution inside a pixel cluster to resolve tracks that share one of more of their pixel detector hits. In practice, the pixel charge is discretized using the Time-over-Threshold (ToT) technique. More charge information is better for discrimination, but more challenging for designing and operating the detector. A model of the silicon pixels has been developed in order to study the impact of the precision of the digitized charge distribution on distinguishing multi-particle clusters. The output of the GEANT4-based simulation is used to train neutral networks that predict the multiplicity and location of particles depositing energy inside one cluster of pixels. By studying the multi-particle cluster identification efficiency and position resolution, we quantify the trade-off between the number of ToT bits and low-level tracking inputs. As both ATLAS and CMS are designing upgraded detectors, this work provides guidance for the pixel module designs to meet TIDE needs. Work funded by the China Scholarship Council and the Office of High Energy Physics of the U.S. Department of Energy under contract DE-AC02-05CH11231.

  17. Fermilab booster modeling and space charge study

    SciTech Connect

    Weiren Chou et al.

    2003-06-04

    The Fermilab Booster is a bottleneck limiting the proton beam intensity in the accelerator complex. A study group has been formed in order to have a better understanding of this old machine and seek possible improvements. The work includes lattice modeling, numerical simulations, bench measurements and beam studies. Based on newly obtained information, it has been found that the machine acceptance is severely compromised by the orbit bump and dogleg magnets. This, accompanied by emittance dilution from space charge at injection, is a major cause of the large beam loss at the early stage of the cycle. Measures to tackle this problem are being pursued.

  18. Solar Array and Auroral Charging Studies of DMSP Spacecraft

    NASA Technical Reports Server (NTRS)

    Matias, Kelwin

    2013-01-01

    The SSJ electrostatic analyzers and the SSIES plasma instruments on the DMSP spacecraft in low Earth polar orbit can be used to conduct case studies of auroral and solar array charging. We will use a program written in the Interactive Data Language (IDL) to evaluate questionable charging events in the SSJ records by comparing charging signatures in SSJ and SSIES data. In addition, we will assemble a number of case studies of solar array charging showing the signatures from the SSJ data and compare to the SSIES charging signatures. In addition we will use Satellite Tool Kit (STK) to propagate orbits, obtain solar intensity, and use to verify onset of charging with sunrise.

  19. Stratified charge rotary engine combustion studies

    NASA Technical Reports Server (NTRS)

    Shock, H.; Hamady, F.; Somerton, C.; Stuecken, T.; Chouinard, E.; Rachal, T.; Kosterman, J.; Lambeth, M.; Olbrich, C.

    1989-01-01

    Analytical and experimental studies of the combustion process in a stratified charge rotary engine (SCRE) continue to be the subject of active research in recent years. Specifically to meet the demand for more sophisticated products, a detailed understanding of the engine system of interest is warranted. With this in mind the objective of this work is to develop an understanding of the controlling factors that affect the SCRE combustion process so that an efficient power dense rotary engine can be designed. The influence of the induction-exhaust systems and the rotor geometry are believed to have a significant effect on combustion chamber flow characteristics. In this report, emphasis is centered on Laser Doppler Velocimetry (LDV) measurements and on qualitative flow visualizations in the combustion chamber of the motored rotary engine assembly. This will provide a basic understanding of the flow process in the RCE and serve as a data base for verification of numerical simulations. Understanding fuel injection provisions is also important to the successful operation of the stratified charge rotary engine. Toward this end, flow visualizations depicting the development of high speed, high pressure fuel jets are described. Friction is an important consideration in an engine from the standpoint of lost work, durability and reliability. MSU Engine Research Laboratory efforts in accessing the frictional losses associated with the rotary engine are described. This includes work which describes losses in bearing, seal and auxillary components. Finally, a computer controlled mapping system under development is described. This system can be used to map shapes such as combustion chamber, intake manifolds or turbine blades accurately.

  20. Charge-coupled device image sensor study

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The design specifications and predicted performance characteristics of a Charge-Coupled Device Area Imager and a Charge-Coupled Device Linear Imager are presented. The Imagers recommended are intended for use in space-borne imaging systems and therefore would meet the requirements for the intended application. A unique overlapping metal electrode structure and a buried channel structure are described. Reasons for the particular imager designs are discussed.

  1. A- THE NATIONAL CHILDREN'S STUDY

    EPA Science Inventory

    The National Children's Study (NCS) will be the largest long-term study of children's health and development ever conducted in the United States. The NCS will examine a broad range of environmental influences on children's health and development. It will follow approximately 10...

  2. Charge neutralization as studied experimentally and theoretically

    NASA Technical Reports Server (NTRS)

    Linson, L. M.

    1982-01-01

    Problems regarding an isolated sphere which emits negative charge are considered. Such a sphere could charge up to large potentials which would inhibit the electron beam from leaving the vicinity of the body. In order to avoid charging to high potentials, a vehicle must attract a return current equal to the emitted current. The present investigation is concerned with theoretical models of some processes believed to be important for the vehicle neutralization problem under various conditions. Attention is given to general time-scale considerations, the low-altitude regime, the high-altitude regime, vehicle-induced discharge, and beam-plasma discharge. The general pattern which emeres as a result of measurements is that below altitudes of approximately 125 + or - 5 km the vehicle potential rarely rises more than several tens of volts.

  3. Charged particle multiplicity studies with PHOBOS.

    SciTech Connect

    Alver, B.; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Physics; Massachusetts Inst. of Tech.; BNL

    2008-01-01

    Summary and conclusion: (1) Multiplicity - PHOBOS have performed complete charged particle multiplicity measurements for Au+Au, Cu+Cu, d+Au, and p+p collisions, System size dependence, and 'Complete' pseudorapidity distributions; 'Universality' compared to elementary e+e- collisions; and (2) Midrapidity multiplicity - Factorization of centrality and energy dependencies; (3) Limiting fragmentation - extended longitudinal scaling - Seen for Au+Au, Cu+Cu, and d+Au, Also observed in flow observables; (4) Total charged particle multiplicity - N{sub ch}/N{sub part} constant with centrality, (5) Future - Finish up many analysis and reviews.

  4. Study of digital charge coupled devices

    NASA Technical Reports Server (NTRS)

    Wilson, D. D.; Young, V. F.

    1980-01-01

    Charge coupled devices represent unique usage of the metal oxide semiconductor concept. These devices can sample an AC signal at the input, transfer charge proportional to this signal through the CCD shift register and then provide an output of the same frequency and shape as the input. The delay time between input and output is controlled by the CCD operating frequency and the number of stages in the shift resistor. This work is a reliability evaluation of the buried channel and surface channel CCD technologies. The constructions are analyzed, failure modes are described, and test results are reported.

  5. Hybrid charged-particle guide for studying (n, charged particle) reactions

    SciTech Connect

    Haight, R.C.; White, R.M.; Zinkle, S.J.

    1982-08-25

    Charged-particle transport systems consisting of magnetic quadrupole lenses have been employed in recent years in the study of (n, charged particle) reactions. We have completed a new transport system that is based both on magnetic lenses as well as electrostatic fields. The magnetic focusing of this charged-particle guide is provided by six magnetic quadrupole lenses arranged in a CDCCDC sequence (in the vertical plane). The electrostatic field is produced by a wire at high voltage which stretches the length of the guide and is physically at the center of the magnetic axis. The magnetic lenses are used for charged particles above 5 MeV; the electrostatic guide is used for lower energies. This hybrid system possesses the excellent focusing and background rejection properties of other magnetic systems. For low energy charged-particles, the electrostatic transport avoids the narrow band-passes in charged-particle energy which are a problem with purely magnetic transport systems. This system is installed at the LLNL Cyclograaff facility for the study of (n, charged particle) reactions at neutron energies up to 35 MeV.

  6. Neural Activation Underlying Cognitive Control in the Context of Neutral and Affectively Charged Pictures in Children

    ERIC Educational Resources Information Center

    Lamm, Connie; White, Lauren K.; McDermott, Jennifer Martin; Fox, Nathan A.

    2012-01-01

    The neural correlates of cognitive control for typically developing 9-year-old children were examined using dense-array ERPs and estimates of cortical activation (LORETA) during a go/no-go task with two conditions: a neutral picture condition and an affectively charged picture condition. Activation was estimated for the entire cortex after which…

  7. Solar Array and Auroral Charging Studies of DMSP Spacecraft

    NASA Technical Reports Server (NTRS)

    Matias, Kelwin

    2013-01-01

    The SSJ electrostatic analyzers and the SSIES plasma instruments on the DMSP spacecraft in low Earth polar orbit can be used to conduct case studies of auroral and solar array charging. We will use a program written in the Interactive Data Language (IDL) to evaluate questionable charging events in the SSJ records by comparing charging signatures in SSJ and SSIES data. In addition, we will assemble a number of case studies of solar array charging showing the signatures from the SSJ data and compare them to the SSIES charging signatures. In addition, we will use Satellite Tool Kit (STK) to propagate orbits, obtain solar intensity, and use to verify onset of charging with sunrise.

  8. "In Charge of the Truffula Seeds": On Children's Literature, Rationality and Children's Voices in Philosophy

    ERIC Educational Resources Information Center

    Johansson, Viktor

    2011-01-01

    In this paper I investigate how philosophy can speak for children and how children can have a voice in philosophy and speak for philosophy. I argue that we should understand children as responsible rational individuals who are involved in their own philosophical inquiries and who can be involved in our own philosophical investigations--not because…

  9. 42 CFR 457.540 - Cost-sharing charges for children in families with incomes at or below 150 percent of the FPL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Responsibilities § 457.540 Cost-sharing charges for children in families with incomes at or below 150 percent of... sharing and other similar charges for children whose family income is at or below 150 percent of the FPL... charges for children whose family income is at or below 100 percent of the FPL are equal to or less...

  10. Kop- och saljsystem inom barnomsorgen: Konsekvenser for Personal, Foraldrar och barn (A New Charging System in Child Care: Consequences for Personnel, Parents, and Children).

    ERIC Educational Resources Information Center

    Ekholm, Bodil; Ellstrom, Eva

    The aim of this study was to examined the impact of a new charging system in child care in two different Swedish municipalities, on personnel, parents, and children. Four day care centers situated in different socioeconomic areas were studied. A qualitative approach was used, and data were collected by means of interviews and a questionnaire.…

  11. A spacecraft charging study on the SCEX 3 rocket

    NASA Technical Reports Server (NTRS)

    Mullen, E. G.; Gussenhoven, M. S.; Hardy, D. A.; Murphy, G. P.; Lloyd, J. W. F.; Slutter, W.; Malcolm, P.; Kellogg, P. J.; Monson, S.

    1991-01-01

    Instruments on the SCEX 3 rocket payload were used to study charging during electron beam emissions. The data show that electrostatic analyzers can be used to measure vehicle charging and direct beam return currents in dense plasma conditions. The data also show return current dependencies on pitch angle, beam current and beam energy. It is found that if the proper care is taken, ESAs can be used to detect charging on vehicles in low altitude orbits which are contaminated with high levels of outgassing and in dense plasma regimes. These results are particularly important for the TSS-1 electrodynamic tether program where ESAs are being used to determine Shuttle charging levels during tether employment and to look for high fluxes of directly returning electrons during electron generator operations to balance the Shuttle charging.

  12. Electrostatic interaction between nonuniformly charged colloids: experimental and numerical study.

    PubMed

    Derot, Claire; Porcar, Lionel; Lee, YongJin; Pincus, Phillip A; Jho, YongSeok; In, Martin

    2015-02-10

    The influence of the surface charge distribution on the interaction between nanosized particles in water is reported. The distribution of charges at the surface of initially neutral microemulsion droplets has been modulated by additions of various oligomeric cationic surfactants. The osmotic compressibility of the doped microemulsions was measured by light and small-angle neutrons scattering and reveals that the overall effective interaction induced by the ionic groups is repulsive. However, particular charge distributions decrease the osmotic compressibility much less than others. Independent measurements of the activity of the bromide counterions with specific electrodes evidence a significant decrease in the effective charge, which, however, cannot account for the osmotic compressibility in the framework of the primitive model. The q dependence of the structure factor reveals an attractive contribution over a short distance. Numerical studies assign this attractive contribution to the overlap of hydration shells that are extended as a result of the charge localization.

  13. A spacecraft charging study on the SCEX 3 rocket

    SciTech Connect

    Mullen, E.G.; Gussenhoven, M.S.; Hardy, D.A.; Murphy, G.P.; Lloyd, J.W.F.; Slutter, W. ); Malcolm, P. ); Kellogg, P.J.; Monson, S. )

    1991-12-01

    Instruments on the SCEX 3 rocket payload flown from the Poker Flats Rocket Range in February 1990 were used to study charging during electron beam emissions. This paper reports that the data show that electrostatic analyzers can be used to measure vehicle charging and direct beam return currents in dense plasma conditions. The data also show return current dependencies on pitch angle, beam current and beam energy.

  14. Early oral sensory experiences and feeding development in children with CHARGE syndrome: a report of five cases.

    PubMed

    Dobbelsteyn, Cindy; Marche, Darlene M; Blake, Kim; Rashid, Mohsin

    2005-01-01

    Children with CHARGE syndrome commonly experience feeding and swallowing problems. Difficulties may be associated with congenital structural anomalies, motor impairment, and/or oral sensory impairment. For many children with CHARGE syndrome, the introduction of functional oral feeding is delayed and there are often long-term feeding complications. Oral aversion or defensiveness is a frequent serious issue; however, it is uncertain whether this is a primary sensory disorder or secondary to delayed and/or negative oral sensory and feeding experiences. This article examines in detail the early oral sensory and feeding experiences of five children with CHARGE syndrome, through a review of medical records and caregiver questionnaires. Findings indicate variable early oral sensory experiences in this group of children, with all of the children having some difficulty or delay in the development of oral feeding and swallowing. The nature of these difficulties and the potential contributory factors are discussed.

  15. Laboratory Studies of Thermal Energy Charge Transfer of Multiply Charged Ions in Astrophysical Plasmas

    NASA Technical Reports Server (NTRS)

    Kwong, Victor H. S.

    2003-01-01

    The laser ablation/ion storage facility at the UNLV Physics Department has been dedicated to the study of atomic and molecular processes in low temperature plasmas. Our program focuses on the charge transfer (electron capture) of multiply charged ions and neutrals important in astrophysics. The electron transfer reactions with atoms and molecules is crucial to the ionization condition of neutral rich photoionized plasmas. With the successful deployment of the Far Ultraviolet Spectroscopic Explorer (FUSE) and the Chandra X-ray Observatory by NASA high resolution VUV and X-ray emission spectra fiom various astrophysical objects have been collected. These spectra will be analyzed to determine the source of the emission and the chemical and physical environment of the source. The proper interpretation of these spectra will require complete knowledge of all the atomic processes in these plasmas. In a neutral rich environment, charge transfer can be the dominant process. The rate coefficients need to be known accurately. We have also extended our charge transfer measurements to KeV region with a pulsed ion beam. The inclusion of this facility into our current program provides flexibility in extending the measurement to higher energies (KeV) if needed. This flexibility enables us to address issues of immediate interest to the astrophysical community as new observations are made by high resolution space based observatories.

  16. Charge collection studies in irradiated HV-CMOS particle detectors

    NASA Astrophysics Data System (ADS)

    Affolder, A.; Andelković, M.; Arndt, K.; Bates, R.; Blue, A.; Bortoletto, D.; Buttar, C.; Caragiulo, P.; Cindro, V.; Das, D.; Dopke, J.; Dragone, A.; Ehrler, F.; Fadeyev, V.; Galloway, Z.; Gorišek, A.; Grabas, H.; Gregor, I. M.; Grenier, P.; Grillo, A.; Hommels, L. B. A.; Huffman, T.; John, J.; Kanisauskas, K.; Kenney, C.; Kramberger, G.; Liang, Z.; Mandić, I.; Maneuski, D.; McMahon, S.; Mikuž, M.; Muenstermann, D.; Nickerson, R.; Perić, I.; Phillips, P.; Plackett, R.; Rubbo, F.; Segal, J.; Seiden, A.; Shipsey, I.; Song, W.; Stanitzki, M.; Su, D.; Tamma, C.; Turchetta, R.; Vigani, L.; Volk, J.; Wang, R.; Warren, M.; Wilson, F.; Worm, S.; Xiu, Q.; Zavrtanik, M.; Zhang, J.; Zhu, H.

    2016-04-01

    Charge collection properties of particle detectors made in HV-CMOS technology were investigated before and after irradiation with reactor neutrons. Two different sensor types were designed and processed in 180 and 350 nm technology by AMS. Edge-TCT and charge collection measurements with electrons from 90Sr source were employed. Diffusion of generated carriers from undepleted substrate contributes significantly to the charge collection before irradiation, while after irradiation the drift contribution prevails as shown by charge measurements at different shaping times. The depleted region at a given bias voltage was found to grow with irradiation in the fluence range of interest for strip detectors at the HL-LHC. This leads to large gains in the measured charge with respect to the one before irradiation. The increase of the depleted region was attributed to removal of effective acceptors. The evolution of depleted region with fluence was investigated and modeled. Initial studies show a small effect of short term annealing on charge collection.

  17. Space charge studies in FFAG using the tracking code Zgoubi

    SciTech Connect

    Tahar, M. Haj; Meot, F.; Tsoupas, N.

    2015-05-03

    A method is implemented in Zgoubi that allows the computation of space charge effects in 2D distributions and with some restrictions in 3D distributions. It relies on decomposing field maps or analytical elements into slices and applying a space charge kick to the particles. The aim of this study is to investigate the accuracy of this technique, its limitations/advantages by comparisons with other linear/nonlinear computation methods and codes, and to apply it to high power fixed field ring design studies.

  18. EEG Studies with Young Children.

    ERIC Educational Resources Information Center

    Flohr, John W.; Miller, Daniel C.; deBeus, Roger

    2000-01-01

    Describes how electroencephalogram (EEG) data are collected and how brain function is measured. Discusses studies on the effects of music experiences with adult subjects and studies focusing on the effects of music training on EEG activity of children and adolescents. Considers the implications of the studies and the future directions of this…

  19. Instrumentation for Studies of Electron Emission and Charging From Insulators

    NASA Technical Reports Server (NTRS)

    Thomson, C. D.; Zavyalov, V.; Dennison, J. R.

    2004-01-01

    Making measurements of electron emission properties of insulators is difficult since insulators can charge either negatively or positively under charge particle bombardment. In addition, high incident energies or high fluences can result in modification of a material s conductivity, bulk and surface charge profile, structural makeup through bond breaking and defect creation, and emission properties. We discuss here some of the charging difficulties associated with making insulator-yield measurements and review the methods used in previous studies of electron emission from insulators. We present work undertaken by our group to make consistent and accurate measurements of the electron/ion yield properties for numerous thin-film and thick insulator materials using innovative instrumentation and techniques. We also summarize some of the necessary instrumentation developed for this purpose including fast response, low-noise, high-sensitivity ammeters; signal isolation and interface to standard computer data acquisition apparatus using opto-isolation, sample-and-hold, and boxcar integration techniques; computer control, automation and timing using Labview software; a multiple sample carousel; a pulsed, compact, low-energy, charge neutralization electron flood gun; and pulsed visible and UV light neutralization sources. This work is supported through funding from the NASA Space Environments and Effects Program and the NASA Graduate Research Fellowship Program.

  20. Experimental Studying of Dust Particles Charging by Electron Beam

    SciTech Connect

    Gavrikov, A. V.; Fortov, V. E.; Petrov, O. F.; Vorona, N. A.; Vasiliev, M. N.

    2008-09-07

    The studying of the dusty plasma properties under electron beam action are of great interest because it gives the unique opportunities for experimental investigation of strongly coupled systems as well as for developing the new dusty plasma technologies of creating the new composite materials. Highly charged dust particle generates electrostatic field that can accelerate positive ions to high power. It gives the unique possibilities of using these macroparticles (for deeply ions implantation, as catalysts for increasing rate of reactions with the high energy barrier, in the new ionic engines etc.). Presented work deals with the experimental investigation of dust particles charging under direct influence of electron beam. On the basis of experimental data the average velocities of dust particles were obtained and the charge of macroparticle was estimated.

  1. Children's Literature in Social Studies.

    ERIC Educational Resources Information Center

    Ediger, Marlow

    Children's literature and the social studies need to be integrated so that holism is involved in pupil learning. A variety of kinds of reading materials should be available to learners so that each social studies unit might be meaningful and interesting. Individual differences among pupils' abilities and achievements must be adequately provided…

  2. [Time-resolved optical studies of charge relaxation and charge transfer at electrode interfaces

    SciTech Connect

    Not Available

    1992-01-01

    Key components were identified in a quantitative model of carrier relaxation in semiconductor electrodes: nonlinear aspects of nonradiative and radiative recombination, effect of space charge field on carrier dynamics, self-absorption effects in direct gas semiconductors, and influence of surface state population kinetics on charge carrier recombination. For CdSe, the first three are operative (no direct proof of the last one). A realistic kinetic model for carrier recombination in the bulk of CdSe was used which includes important nonlinear effects, both radiative and nonradiative. The change in interfacial recombination velocity with the chemical nature of the sinterface was studied (n-CdSe/silane interfaces). Temperature effect (278 to 328 K) on fluorescence decay of n-CdSe in contact with 0.5 M KOH was found to be weak. An analytical solution was obtained for time-resolved fluoresence from electrodes under potential bias, and is being tested. Fluorescence work on a different material, CdS, indicate different recombination kinetics; this material was used to directly pump an optical transition of a surface state.

  3. [Time-resolved optical studies of charge relaxation and charge transfer at electrode interfaces

    SciTech Connect

    Not Available

    1992-12-31

    Key components were identified in a quantitative model of carrier relaxation in semiconductor electrodes: nonlinear aspects of nonradiative and radiative recombination, effect of space charge field on carrier dynamics, self-absorption effects in direct gas semiconductors, and influence of surface state population kinetics on charge carrier recombination. For CdSe, the first three are operative (no direct proof of the last one). A realistic kinetic model for carrier recombination in the bulk of CdSe was used which includes important nonlinear effects, both radiative and nonradiative. The change in interfacial recombination velocity with the chemical nature of the sinterface was studied (n-CdSe/silane interfaces). Temperature effect (278 to 328 K) on fluorescence decay of n-CdSe in contact with 0.5 M KOH was found to be weak. An analytical solution was obtained for time-resolved fluoresence from electrodes under potential bias, and is being tested. Fluorescence work on a different material, CdS, indicate different recombination kinetics; this material was used to directly pump an optical transition of a surface state.

  4. Studies of Ion Beam Charge Neutralization by Ferroelectric Plasma Sources

    NASA Astrophysics Data System (ADS)

    Stepanov, A.; Gilson, E. P.; Grisham, L.; Davidson, R. C.

    2013-10-01

    Space-charge forces limit the possible transverse compression of high perveance ion beams that are used in ion-beam-driven high energy density physics applications; the minimum radius to which a beam can be focused is an increasing function of perveance. The limit can be overcome if a plasma is introduced in the beam path between the focusing element and the target in order to neutralize the space charge of the beam. This concept has been implemented on the Neutralized Drift Compression eXperiment (NDCX) at LBNL using Ferroelectric Plasma Sources (FEPS). In our experiment at PPPL, we propagate a perveance-dominated ion beam through a FEPS to study the effect of the neutralizing plasma on the beam envelope and its evolution in time. A 30-60 keV space-charge-dominated Argon beam is focused with an Einzel lens into a FEPS located at the beam waist. The beam is intercepted downstream from the FEPS by a movable Faraday cup that provides time-resolved 2D current density profiles of the beam spot on target. We report results on: (a) dependence of charge neutralization on FEPS plasma density; (b) effects on beam emittance, and (c) time evolution of the beam envelope after the FEPS pulse. Research supported by the U.S. Department of Energy.

  5. Study of longitudinal dynamics in space-charge dominated beams

    NASA Astrophysics Data System (ADS)

    Tian, Kai

    Modern accelerator applications, such as heavy ion fusion drivers, pulsed neutron sources, electron injectors for high-energy linear colliders, and X-ray Free Electron Lasers, demand beams with high intensity, low emittance and small energy spread. At low (non-relativistic) energies, the "electrostatic", collective interactions from space-charge forces existing in such intense beams play the dominant role; we characterize these beams as space-charge dominated beams. This dissertation presents numerous new findings on the longitudinal dynamics of a space-charge dominated beam, particularly on the propagation of density perturbations. In order to fully understand the complex physics of longitudinal space-charge waves, we combine the results of theory, computer simulation, and experiment. In the Long Solenoid Experimental system (LSE), with numerous diagnostic tools and techniques, we have, for the first time, experimentally measured the detailed energy profiles of longitudinal space-charge waves at different locations, both near the beam source and at the end of the transport system. Along with the current profiles, we have a complete set of experimental data for the propagation of space-charge waves. We compare these measured results to a 1-D theory and find better agreement for beams with perturbations in the linear regime, where the perturbation strength is less than 10%, than those with nonlinear perturbations. Using fast imaging techniques that we newly developed, we have, for the first time, obtained the progressive time-resolved images of longitudinal slices of a space-charge dominated beam. These images not only provide us time-resolved transverse density distribution of the beam, but also enable us to take time-resolved transverse phase space measurement using computerized tomography. By combining this information with the longitudinal energy measurement, we have, for the first time, experimentally constructed the full 6-D phase space. Part of the results

  6. Children, Technology, and Social Studies. Children's Literature.

    ERIC Educational Resources Information Center

    Lombard, Robert H, Ed.; And Others

    1995-01-01

    Maintains that the role of technology and its civic implications can be explored through children's literature. Provides a bibliographical essay of 19 books that address how things work, how technology affects everyday life, and how society shapes its technological future. (CFR)

  7. A time-resolved study on the interaction of oppositely charged bicelles--implications on the charged lipid exchange kinetics.

    PubMed

    Yang, Po-Wei; Lin, Tsang-Lang; Hu, Yuan; Jeng, U-Ser

    2015-03-21

    Time-resolved small-angle X-ray scattering was applied to study charged lipid exchange between oppositely charged disc-shaped bicelles. The exchange of charged lipids gradually reduces the surface charge density and weakens the electrostatic attraction between the oppositely charged bicelles which form alternately stacked aggregates upon mixing. Initially, at a high surface charge density with almost no free water layer between the stacked bicelles, fast exchange kinetics dominate the exchange process. At a later stage with a lower surface charge density and a larger water gap between the stacked bicelles, slow exchange kinetics take over. The fast exchange kinetics are correlated with the close contact of the bicelles when there is almost no free water layer between the tightly bound bicelles with a charged lipid exchange time constant as short as 20-40 min. When the water gap becomes large enough to have a free water layer between the stacked bicelles, the fast lipid exchange kinetics are taken over by slow lipid exchange kinetics with time constants around 200-300 min, which are comparable to the typical time constant of lipid exchange between vesicles in aqueous solution. These two kinds of exchange mode fit well with the lipid exchange models of transient hemifusion for the fast mode and monomer exchange for the slow mode.

  8. Children and Clinical Studies: Why Clinical Studies Are Important

    MedlinePlus Videos and Cool Tools

    ... Clinical Studies Children have often had to accept medicines and treatments based on what is known to ... children's health with the goal to develop treatments, drugs, and devices specific to children. Resources for a ...

  9. Raman scattering studies and charge transport in polyfluorenes

    NASA Astrophysics Data System (ADS)

    Arif, Mohammad Ali Iftekhar

    Organic semiconductors, such as short-chain oligomers and long-chain polymers, are now a core constituent in numerous organic and organic-inorganic hybrid technologies. Blue-emitting polyfluorenes (PFs) have emerged as especially attractive pi conjugated polymers (CP) due to their high luminescence efficiency and excellent electronic properties and thus great prospects for device applications. The performance of devices based on these polymers depends on side chain conformations, overall crystalline structure, and charge transport processes at the microscopic level. This project entails detailed Raman scattering studies and charge transport properties of two side chain substituted PFs: Poly(2,7-[9,9'-bis(2-ethylhexyl)] fluorene) (PF2/6) and Poly(9,9-(di-n,n-octyl) fluorene) (PF8). The structural properties of PFs are extremely sensitive to the choice of functionalizing side chains. PF8 adopts metastable structures that depend upon the thermal history and choice of solvents used in film forming conditions. Raman scattering techniques as a function of thermal cycling are used to monitor the changes in the backbone and side chain morphology of PF8. These studies establish a correlation between the conformational isomers and the side and main chain morphology. Theoretical modeling of the vibrational spectra of single chain oligomers in conjunction with the experimental results demonstrate the incompatibility of the beta phase, a low energy emitting chromophore, with the overall crystalline phase in PF8. Further, electroluminescence and photoluminescence measurements from PF-based light-emitting diodes (LEDs) are presented and discussed in terms of the crystalline phases and chain morphologies in the PFs. Charge carrier injection and transport properties of PF-based LEDs are presented using current-voltage (I--V) characteristic which is modeled by a space-charge-limited conduction (SCLC) for discrete and continuous traps. PF2/6 with a high level of molecular disorder is

  10. Charge transport studies of proton and ion conducting materials

    NASA Astrophysics Data System (ADS)

    Versek, Craig Wm

    The development of a high-throughput impedance spectroscopy instrumentation platform for conductivity characterization of ion transport materials is outlined. Collaborative studies using this system are summarized. Charge conduction mechanisms and conductivity data for small molecule proton conducting liquids, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, and select mixtures of these compounds are documented. Furthermore, proton diffusivity measurements using a Pulse Field Gradient Nuclear Magnetic Resonance (PFG NMR) technique for imidazole and 1,2,3-triazole binary mixtures are compared. Studies of azole functionalized discotic and linear mesogens with conductivity, structural, and thermal characterizations are detailed.

  11. Studies on Charge Variation and Waves in Dusty Plasmas

    NASA Astrophysics Data System (ADS)

    Kausik, Siddhartha Sankar

    Plasma and dust grains are both ubiquitous ingredients of the universe. The interplay between them has opened up a new and fascinating research domain, that of dusty plasmas, which contain macroscopic particles of solid matter besides the usual plasma constituents. The research in dusty plasmas received a major boost in the early eighties with Voyager spacecraft observation on the formation of Saturn rings. Dusty plasmas are defined as partially or fully-ionized gases that contain micron-sized particles of electrically charged solid material, either dielectric or conducting. The physics of dusty plasmas has recently been studied intensively because of its importance for a number of applications in space and laboratory plasmas. This thesis presents the experimental studies on charge variation and waves in dusty plasmas. The experimental observations are carried out in two different experimental devices. Three different sets of experiments are carried out in two different experimental devices. Three different sets of experiments are carried out to study the dust charge variation in a filament discharge argon plasma. The dust grains used in these experiments are grains of silver. In another get of experiment, dust acoustic waves are studied in a de glow discharge argon plasma. Alumina dust grains are sprinkled in this experiment. The diagnostic tools used in these experiments are Langmuir probe and Faraday cup. The instruments used in these experiments are electrometer, He-Ne laser and charge coupled device (CCD) camera. Langmuir probe is used to measure plasma parameters, while Faraday cup and electrometer are used to measure very low current (~pA) carried by a collimated dust beam. He-Ne laser illuminates the dust grains and CCD camera is used to capture the images of dust acoustic waves. Silver dust grains are produced in the dust chamber by gas-evaporation technique. Due to differential pressure maintained between the dust and plasma chambers, the dust grains move

  12. Numerical study of superradiant instability for charged stringy black hole-mirror system

    NASA Astrophysics Data System (ADS)

    Li, Ran; Zhao, Junkun

    2015-01-01

    We numerically study the superradiant instability of charged massless scalar field in the background of charged stringy black hole with mirror-like boundary condition. We compare the numerical result with the previous analytical result and show the dependencies of this instability upon various values of black hole charge Q, scalar field charge q, and mirror radius rm. Especially, we have observed that imaginary part of BQN frequencies grows with the scalar field charge q rapidly.

  13. A numerical study on liquid charging inside electrostatic atomizers

    NASA Astrophysics Data System (ADS)

    Kashir, Babak; Perri, Anthony; Sankaran, Abhilash; Staszel, Christopher; Yarin, Alexander; Mashayek, Farzad

    2016-11-01

    The charging of the dielectric liquid inside an electrostatic atomizer is studied numerically by developing codes based on the OpenFOAM platform. Electrostatic atomization is an appealing technology in painting, fuel injection and oil coating systems due to improved particle-size distribution, enhanced controlability of droplets' trajectories and lower power consumption. The numerical study is conducted concurrently to an experimental investigation to facilitate the validation and deliver feedback for further development. The atomizer includes a pin electrode that is placed at the center of a converging chamber. The chamber orifice is located at a known distance from the electrode tip. The pin electrode is connected to a high voltage that leads to the charging of the liquid. In the present work, the theoretical foundations of separated treatment of the polarized layer and the electronuetral bulk flow are set by describing the governing equations, relevant boundary conditions and the matching condition between these two domains. The resulting split domains are solved numerically to find the distribution of velocity and electrostatic fields over the specified regions. National Science Foundation Award Number: 1505276.

  14. Study on space charge compensation in negative hydrogen ion beam

    SciTech Connect

    Zhang, A. L.; Chen, J. E.; Peng, S. X. Ren, H. T.; Zhang, T.; Zhang, J. F.; Xu, Y.; Guo, Z. Y.

    2016-02-15

    Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H{sup +} beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H{sup −} beam from a 2.45 GHz microwave driven H{sup −} ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results.

  15. Advanced stratified charge rotary aircraft engine design study

    NASA Technical Reports Server (NTRS)

    Badgley, P.; Berkowitz, M.; Jones, C.; Myers, D.; Norwood, E.; Pratt, W. B.; Ellis, D. R.; Huggins, G.; Mueller, A.; Hembrey, J. H.

    1982-01-01

    A technology base of new developments which offered potential benefits to a general aviation engine was compiled and ranked. Using design approaches selected from the ranked list, conceptual design studies were performed of an advanced and a highly advanced engine sized to provide 186/250 shaft Kw/HP under cruise conditions at 7620/25,000 m/ft altitude. These are turbocharged, direct-injected stratified charge engines intended for commercial introduction in the early 1990's. The engine descriptive data includes tables, curves, and drawings depicting configuration, performance, weights and sizes, heat rejection, ignition and fuel injection system descriptions, maintenance requirements, and scaling data for varying power. An engine-airframe integration study of the resulting engines in advanced airframes was performed on a comparative basis with current production type engines. The results show airplane performance, costs, noise & installation factors. The rotary-engined airplanes display substantial improvements over the baseline, including 30 to 35% lower fuel usage.

  16. Halogen bonding: a study based on the electronic charge density.

    PubMed

    Amezaga, Nancy J Martinez; Pamies, Silvana C; Peruchena, Nélida M; Sosa, Gladis L

    2010-01-14

    Density functional theory (DFT) and atoms in molecules theory (AIM) were used to study the characteristic of the noncovalent interactions in complexes formed between Lewis bases (NH(3), H(2)O, and H(2)S) and Lewis acids (ClF, BrF, IF, BrCl, ICl, and IBr). In order to compare halogen and hydrogen bonds interactions, this study included hydrogen complexes formed by some Lewis bases and HF, HCl, and HBr Lewis acids. Ab initio, wave functions were generated at B3LYP/6-311++G(d,p) level with optimized structures at the same level. Criteria based on a topological analysis of the electron density were used in order to characterize the nature of halogen interactions in Lewis complexes. The main purpose of the present work is to provide an answer to the following questions: (a) why can electronegative atoms such as halogens act as bridges between two other electronegative atoms? Can a study based on the electron charge density answer this question? Considering this, we had performed a profound study of halogen complexes in the framework of the AIM theory. A good correlation between the density at the intermolecular bond critical point and the energy interaction was found. We had also explored the concentration and depletion of the charge density, displayed by the Laplacian topology, in the interaction zone and in the X-Y halogen donor bond. From the atomic properties, it was generally observed that the two halogen atoms gain electron population in response to its own intrinsic nature. Because of this fact, both atoms are energetically stabilized.

  17. Study on sources of charging lead acid batteries

    NASA Astrophysics Data System (ADS)

    Diniş, C. M.; Popa, G. N.; Iagăr, A.

    2015-06-01

    The paper presents the general characteristics of lead acid batteries and two charging methods of these batteries. For charging of lead batteries was used an intelligent power source K 8012 (from Velleman). The power source allows fixing the level of the battery voltage and battery capacity. The intelligent power source uses the joint method (at constant current and, then, at constant voltage) and warning that indicates different situations in the charging process. Other method of charging presented in the paper is at constant voltage using a stabilized power source. In the paper experimental measurements were carried out using data acquisition card SER 10 BIT (from Conrad) for charging/ discharging of a lead acid battery 12V/9Ah (using an intelligent power source) and charging of another high capacity lead acid battery 12V/47Ah/390 A (using a stabilized power source). At the discharging of the lead acid batteries it were used automotive lamps as electric loads.

  18. The study of surface acoustic wave charge transfer device

    NASA Technical Reports Server (NTRS)

    Papanicolaou, N.; Lin, H. C.

    1978-01-01

    A surface acoustic wave-charge transfer device, consisting of an n-type silicon substrate, a thermally grown silicon dioxide layer, and a sputtered film of piezoelectric zinc oxide is proposed as a means of circumventing problems associated with charge-coupled device (CCD) applications in memory, signal processing, and imaging. The proposed device creates traveling longitudinal electric fields in the silicon and replaces the multiphase clocks in CCD's. The traveling electric fields create potential wells which carry along charges stored there. These charges may be injected into the wells by light or by using a p-n junction as in conventional CCD's.

  19. THE U.S. NATIONAL CHILDREN'S STUDY

    EPA Science Inventory

    The National Children's Study (NCS) is a study to examine the effects of environmental influences on the health and development of more than 100,000 children across the United States, following them from before birth until age 21. The goal of the study is to understand the factor...

  20. Children with lesbian parents: a community study.

    PubMed

    Golombok, Susan; Perry, Beth; Burston, Amanda; Murray, Clare; Mooney-Somers, Julie; Stevens, Madeleine; Golding, Jean

    2003-01-01

    Existing research on children with lesbian parents is limited by reliance on volunteer or convenience samples. The present study examined the quality of parent-child relationships and the socioemotional and gender development of a community sample of 7-year-old children with lesbian parents. Families were recruited through the Avon Longitudinal Study of Parents and Children, a geographic population study of 14,000 mothers and their children. Thirty-nine lesbian-mother families, 74 two-parent heterosexual families, and 60 families headed by single heterosexual mothers were compared on standardized interview and questionnaire measures administered to mothers, co-mothers/fathers, children, and teachers. Findings are in line with those of earlier investigations showing positive mother-child relationships and well-adjusted children.

  1. Spotlight on Young Children and Social Studies

    ERIC Educational Resources Information Center

    Koralek, Derry, Ed.; Mindes, Gayle, Ed.

    2006-01-01

    When engaged in social studies, with guidance and encouragement from adults, children develop awareness of self and family and become active participants in the larger community. The knowledge and skills learned through social studies prepare children to become informed and engaged citizens of their country and the world. In this collection of…

  2. Laser Studies of - and Charge-Transfer Dynamics

    NASA Astrophysics Data System (ADS)

    Goldman, Jay Robert

    This thesis presents the results of three experiments which use lasers to investigate energy-transfer and charge -transfer dynamics. The dynamical processes studied include nanosecond vibrational energy transfer in molecules, subpicosecond electron relaxation in semiconductors, and subpicosecond initiation of surface bimolecular reactions on a metal crystal. In experiments using time-resolved coherent Raman spectroscopy to probe infrared multiphoton excited molecules, we study CO_2-laser excited SO _2 and SF_6. In SO _2 we observe direct nu _1-mode excitation and distinguish between this process and excitation of the nearly resonant nu_2-mode overtone. In SF _6, we directly observe nu _3-mode excitation followed by collisional energy redistribution to a heat bath of non-pumped modes. Quantitative modeling of the SF_6^ectra yields excited vibrational population distributions and resolves some long-standing inconsistencies between different previously published reports. In an experiment using time-resolved photoelectron spectroscopy, we observe the subpicosecond evolution of an optically-excited nonequilibrium electron distribution in silicon. We observe an electron thermalization time of less than 120 fs, electron equilibration with the lattice in 1 ps, and an energy-dependent electron cooling rate consistent with published calculations of the electron -phonon scattering rate. The results indicate the formation, in 1 ps, of a surface space-charge electron layer with an electron density two orders of magnitude greater than the bulk electron density. In an experiment using 100-fs laser pulses to induce desorption of O_2 and reaction of O_2+CO to form CO_2 on a Pt(111) surface, we present desorption and reaction data obtained over an absorbed fluence range of 1-20 mJ/cm_2 at wavelengths of 800, 400, and 266 nm. We observe a highly nonlinear desorption and reaction yield fluence dependence; the data are fit by a power law model in which the yield is proportional to

  3. A three dimensional dynamic study of electrostatic charging in materials

    NASA Technical Reports Server (NTRS)

    Katz, I.; Parks, D. E.; Mandell, M. J.; Harvey, J. M.; Brownell, D. H., Jr.; Wang, S. S.; Rotenberg, M.

    1977-01-01

    A description is given of the physical models employed in the NASCAP (NASA Charging Analyzer Program) code, and several test cases are presented. NASCAP dynamically simulates the charging of an object made of conducting segments which may be entirely or partially covered with thin dielectric films. The object may be subject to either ground test or space user-specified environments. The simulation alternately treats (1) the tendency of materials to accumulate and emit charge when subject to plasma environment, and (2) the consequent response of the charged particle environment to an object's electrostatic field. Parameterized formulations of the emission properties of materials subject to bombardment by electrons, protons, and sunlight are presented. Values of the parameters are suggested for clean aluminum, Al2O3, clean magnesium, MgO, SiO2 kapton, and teflon. A discussion of conductivity in thin dielectrics subject to radiation and high fields is given, together with a sample calculation.

  4. Use of charging control guidelines for geosynchronous satellite design studies

    NASA Technical Reports Server (NTRS)

    Steves, N. J.

    1980-01-01

    Several of the principle guidelines from the Spacecraft Charging Design Guidelines Handbook are presented with illustrative examples. Use of the geomagnetic substorm specification to qualify satellite designs, the evaluation of satellite designs by using analytical modelling techniques, the use of selected materials and coatings to minimize charging, the tying of all conducting elements to a common ground, and the use of electrical filtering to protect circuits from discharge induced upsets are discussed. Discharge criteria and SCATHA data are excluded.

  5. Neurodevelopmental Disorders and Prenatal Residential Proximity to Agricultural Pesticides: The CHARGE Study

    PubMed Central

    Geraghty, Estella M.; Tancredi, Daniel J.; Delwiche, Lora D.; Schmidt, Rebecca J.; Ritz, Beate; Hansen, Robin L.; Hertz-Picciotto, Irva

    2014-01-01

    Background: Gestational exposure to several common agricultural pesticides can induce developmental neurotoxicity in humans, and has been associated with developmental delay and autism. Objectives: We evaluated whether residential proximity to agricultural pesticides during pregnancy is associated with autism spectrum disorders (ASD) or developmental delay (DD) in the Childhood Autism Risks from Genetics and Environment (CHARGE) study. Methods: The CHARGE study is a population-based case–control study of ASD, DD, and typical development. For 970 participants, commercial pesticide application data from the California Pesticide Use Report (1997–2008) were linked to the addresses during pregnancy. Pounds of active ingredient applied for organophophates, organochlorines, pyrethroids, and carbamates were aggregated within 1.25-km, 1.5-km, and 1.75-km buffer distances from the home. Multinomial logistic regression was used to estimate the odds ratio (OR) of exposure comparing confirmed cases of ASD (n = 486) or DD (n = 168) with typically developing referents (n = 316). Results: Approximately one-third of CHARGE study mothers lived, during pregnancy, within 1.5 km (just under 1 mile) of an agricultural pesticide application. Proximity to organophosphates at some point during gestation was associated with a 60% increased risk for ASD, higher for third-trimester exposures (OR = 2.0; 95% CI: 1.1, 3.6), and second-trimester chlorpyrifos applications (OR = 3.3; 95% CI: 1.5, 7.4). Children of mothers residing near pyrethroid insecticide applications just before conception or during third trimester were at greater risk for both ASD and DD, with ORs ranging from 1.7 to 2.3. Risk for DD was increased in those near carbamate applications, but no specific vulnerable period was identified. Conclusions: This study of ASD strengthens the evidence linking neurodevelopmental disorders with gestational pesticide exposures, particularly organophosphates, and provides novel results of

  6. EXAFS study of dopant ions with different charges in nanocrystalline anatase: evidence for space-charge segregation of acceptor ions.

    PubMed

    Knauth, Philippe; Chadwick, Alan V; Lippens, Pierre E; Auer, Gerhard

    2009-06-02

    Nanocrystalline TiO(2) (anatase) is an essential oxide for environment and energy applications. A combination of EXAFS spectroscopy and DFT calculations on a series of dopants with quite similar ion radius, but increasing ion charge, show boundary space charge segregation of acceptor cations. The picture illustrates the Fourier-transformed EXAFS spectrum for Sn(4+)-doped TiO(2).A series of dopants, including acceptor ions (Zn(2+), Y(3+)), isovalent ions (Zr(4+), Sn(4+)) as well as a donor ion (Nb(5+)), were studied by EXAFS spectroscopy in nanocrystalline TiO(2) anatase powders and nanoceramics. Similar results were found for nanocrystalline powders and nanocrystalline ceramics, made by hot-pressing the powders. Boundary segregation was observed for the acceptor ions yttrium and zinc, whereas tin, zirconium and niobium ions were placed on substitutional bulk sites and did not segregate, whatever their concentration. These results can be interpreted based on defect thermodynamics, in the framework of a space charge segregation model with positive boundary core, due to excess oxide ion vacancies, and negative space charge regions, where ionized acceptors are segregated.

  7. A Study of Charged Current Single Charged Pion Productions on Carbon in a Few-GeV Neutrino Beam

    SciTech Connect

    Hiraide, Katsuki

    2009-01-01

    Understanding single charged pion production via neutrino-nucleus charged current interaction in the neutrino energy region of a few GeV is essential for future neutrino oscillation experiments since this process is a dominant background for vμ → vx oscillation measurements. There are two contributions to this process: single pion production via baryonic resonance (vμN → μ-+) and coherent pion production interacting with the entire nucleus (vμA → μ-+), where N is nucleon in the nucleus and A is the nucleus. The purpose of the study presented in this thesis is a precise measurement of charged current single charged pion productions, resonant and coherent pion productions, with a good final state separation in the neutrino energy region of a few GeV. In this thesis, we focus on the study of charged current coherent pion production from muon neutrinos scattering on carbon, vμ 12C → μ-12+, in the SciBooNE experiment. This is motivated by the fact that without measuring this component first, the precise determination of resonant pion production cross section can not be achieved since the contribution of coherent pion production in the region of small muon scattering angle is not small. Furthermore, the coherent process is particularly interesting because it is deeply rooted in fundamental physics via Adler's partially conserved axial-vector current theorem. We took data from June 2007 until August 2008, in both the neutrino and antineutrino beam. In total, 2.52 x 1020 protons on target were collected. We have performed a search for charged current coherent pion production by using SciBooNE's full neutrino data set, corresponding to 0.99 x 1020 protons on target. No evidence for coherent pion production is observed. We set 90% confidence level upper limits on the cross section ratio of charged

  8. Case Studies of Environmental Risks to Children.

    ERIC Educational Resources Information Center

    Goldman, Lynn R.

    1995-01-01

    Presents case studies on children's exposure to pesticides, including risks through the use of the insecticide aldicarb on bananas, the home use of diazinon, and the use of interior house paint containing mercury. These cases illustrate how regulatory agencies, parents, health-care providers, and others who come into contact with children have…

  9. Children's Friendship Development: A Comparative Study

    ERIC Educational Resources Information Center

    Yu, SeonYeong; Ostrosky, Michaelene M.; Fowler, Susan A.

    2011-01-01

    Establishing friendships is an important developmental goal of early childhood, but little research has addressed ways in which parents support the friendship development of their young children with disabilities. The purpose of this survey study was to explore the support strategies that parents use to facilitate their children's friendships.…

  10. Young Children's Improvisations: A Longitudinal Study.

    ERIC Educational Resources Information Center

    Flohr, John W.

    The purpose of this study was to characterize the behavior of 2-, 3-, 4-, and 5-year-old children engaged in improvisational musical tasks. Ten subjects from each of the four age levels participated in the 4-year investigation, which lasted until the 2-year-olds reached 5 years of age. Children met individually with the investigator for 15 minutes…

  11. Randomised controlled study of clinical efficacy of spacer therapy in asthma with regard to electrostatic charge

    PubMed Central

    Dompeling, E; Oudesluys-Murphy, A; Janssens, H; Hop, W; Brinkman, J; Sukhai, R; de Jongste, J C

    2001-01-01

    BACKGROUND—Inhalation therapy using a pressured metered dose inhaler (pMDI) and a spacer is frequently used in the treatment of airway disease in children. Several laboratory studies found a clear negative influence of electrostatic charge (ESC) on plastic spacers on the delivery of aerosol.
AIMS—To investigate whether ESC on plastic spacers could diminish bronchodilating responses to salbutamol.
METHODS—Ninety asthmatic children (aged 4-8 years) were randomised into three groups: metal Nebuchamber, plastic Volumatic, and plastic Aerochamber. The bronchodilating response was measured by the change in peak expiratory flow rate (PEF) after 100 µg and 400µg salbutamol. Within the Volumatic and Aerochamber groups, a crossover comparison was made between electrostatic and non-electrostatic spacers.
RESULTS—We found no significant effect of ESC on the bronchodilating response to salbutamol with any of the doses in the Aerochamber and Volumatic groups. For the plastic spacers, the mean difference of the change in PEF after 100 µg salbutamol between non-electrostatic and electrostatic spacers was only +1.7% (95% CI −1.3% to 4.7%). After 400 µg salbutamol this was +1.9% (95% CI −1.4% to 5.1%). A comparable efficacy was found for the Nebuchamber, the Aerochamber, and Volumatic with respect to the change in PEF after 100 and 400 µg salbutamol.
CONCLUSION—This study showed no negative influence of ESC on plastic spacers with regard to clinical efficacy of a β2 agonist (salbutamol) in children with asthma. The metal Nebuchamber, plastic Aerochamber, and plastic Volumatic were equally effective.

 PMID:11159302

  12. Charge transfer properties of pentacene adsorbed on silver: DFT study

    SciTech Connect

    N, Rekha T.; Rajkumar, Beulah J. M.

    2015-06-24

    Charge transfer properties of pentacene adsorbed on silver is investigated using DFT methods. Optimized geometry of pentacene after adsorption on silver indicates distortion in hexagonal structure of the ring close to the silver cluster and deviations in co-planarity of carbon atoms due to the variations in bond angles and dihedral angles. Theoretically simulated absorption spectrum has a symmetric surface plasmon resonance peak around 486nm corresponding to the transfer of charge from HOMO-2 to LUMO. Theoretical SERS confirms the process of adsorption, tilted orientation of pentacene on silver surface and the charge transfers reported. Localization of electron density arising from redistribution of electrostatic potential together with a reduced bandgap of pentacene after adsorption on silver suggests its utility in the design of electro active organic semiconducting devices.

  13. Photoemission studies of novel charge density wave systems

    NASA Astrophysics Data System (ADS)

    Kidd, Timothy Edward

    Photoelectron spectroscopy is a powerful tool for probing the properties of surfaces and interfaces. Linked with a tunable light source such as the Synchrotron Radiation Center in Stoughton, WI, one is able to obtain information concerning the sample's crystal structure, the interfacial properties of thin films, valence band structure, and chemical environment. This thesis is mainly focused on the use of angle-resolved photoemission to study the electronic structure of charge density wave (CDW) systems. CDW systems undergo a temperature dependent structural phase transition accompanied by a modulation of the conduction electron density. These materials share many properties with complex systems. These systems display many novel properties including high-Tc superconductivity and the colossal magnetoresistance effect. One of the shared properties of these systems is a high sensitivity to doping and defects. This sensitivity will be explored in the context of two CDW systems in this thesis. The first system to be studied was the 1/3 ML Sn/Ge(111) surface. It is a simple 2D binary semiconductor system which appears to undergo a CDW phase transition at low temperatures. Photoemission spectroscopy was used to determine the mechanism for the phase transition, and the influence of defects upon the system. It appears the defects play a strong role in defining both the normal and ground state for the system, and are perhaps essential for the phase transition. The second system studied is the layered compound TiSe2. Unlike other group IV transition metal dichalcogenides, TiSe2 undergoes a CDW phase transition at low temperatures. Although the system has been studied for decades, there is still no consensus on the mechanism driving the phase transition. There is also some doubt as to whether the normal state is semi-metallic or semiconducting. Again, defects have a strong effect upon the system. Photoemission studies were used to measure the system's electronic structure near

  14. Study on High Efficient Electric Vehicle Wireless Charging System

    NASA Astrophysics Data System (ADS)

    Chen, H. X.; Liu, Z. Z.; Zeng, H.; Qu, X. D.; Hou, Y. J.

    2016-08-01

    Electric and unmanned is a new trend in the development of automobile, cable charging pile can not meet the demand of unmanned electric vehicle. Wireless charging system for electric vehicle has a high level of automation, which can be realized by unmanned operation, and the wireless charging technology has been paid more and more attention. This paper first analyses the differences in S-S (series-series) and S-P (series-parallel) type resonant wireless power supply system, combined with the load characteristics of electric vehicle, S-S type resonant structure was used in this system. This paper analyses the coupling coefficient of several common coil structure changes with the moving distance of Maxwell Ansys software, the performance of disc type coil structure is better. Then the simulation model is established by Simulink toolbox in Matlab, to analyse the power and efficiency characteristics of the whole system. Finally, the experiment platform is set up to verify the feasibility of the whole system and optimize the system. Based on the theoretical and simulation analysis, the higher charging efficiency is obtained by optimizing the magnetic coupling mechanism.

  15. A Study of CHARGE Syndrome in the UK

    ERIC Educational Resources Information Center

    Deuce, Gail; Howard, Simon; Rose, Steve; Fuggle, Chris

    2012-01-01

    This article reports findings of a questionnaire completed by 44 families living in the UK with a child (aged 15 years or younger) with a medical diagnosis of CHARGE syndrome. The questionnaire contained three sections, namely Diagnosis (including medical and health issues), Child development, and Educational provision. This article reports on the…

  16. A Different Approach to Studying the Charge and Discharge of a Capacitor without an Oscilloscope

    ERIC Educational Resources Information Center

    Ladino, L. A.

    2013-01-01

    A different method to study the charging and discharging processes of a capacitor is presented. The method only requires a high impedance voltmeter. The charging and discharging processes of a capacitor are usually studied experimentally using an oscilloscope and, therefore, both processes are studied as a function of time. The approach presented…

  17. National Children's Study Dietary Assessment Workshop

    Cancer.gov

    The National Children's Study dietary assessment workshop was an opportunity for experts in dietary assessment methodology to gather and discuss the current state of knowledge about methodologies used to assess dietary intake during pregnancy, lactation, infancy, childhood, and adolescence.

  18. A qualitative study of barriers and facilitators of the charge nurse role.

    PubMed

    Connelly, Lynne M; Yoder, Linda H

    2003-01-01

    This qualitative study examines the barriers and facilitators to the role of charge nurse at a medical center. The authors interviewed 42 nursing personnel, including charge nurses (12), head nurses (10), staff nurses (11), and supervisory personnel (9). A total of 24 barriers and facilitators in three categories were identified: personal (11), interpersonal (8), and organizational (5). These factors could be used to inform developmental coaching and educational programs for charge nurses.

  19. Polyelectrolyte adsorption onto like-charged surfaces mediated by trivalent counterions: a Monte Carlo simulation study.

    PubMed

    Luque-Caballero, Germán; Martín-Molina, Alberto; Quesada-Pérez, Manuel

    2014-05-07

    Both experiments and theory have evidenced that multivalent cations can mediate the interaction between negatively charged polyelectrolytes and like-charged objects, such as anionic lipoplexes (DNA-cation-anionic liposome complexes). In this paper, we use Monte Carlo simulations to study the electrostatic interaction responsible for the trivalent-counterion-mediated adsorption of polyelectrolytes onto a like-charged planar surface. The evaluation of the Helmholtz free energy allows us to characterize both the magnitude and the range of the interaction as a function of the polyelectrolyte charge, surface charge density, [3:1] electrolyte concentration, and cation size. Both polyelectrolyte and surface charge favor the adsorption. It should be stressed, however, that the adsorption will be negligible if the surface charge density does not exceed a threshold value. The effect of the [3:1] electrolyte concentration has also been analyzed. In certain range of concentrations, the counterion-mediated attraction seems to be independent of this parameter, whereas very high concentrations of salt weaken the adsorption. If the trivalent cation diameter is doubled the adsorption moderates due to the excluded volume effects. The analysis of the integrated charge density and ionic distributions suggests that a delicate balance between charge inversion and screening effects governs the polyelectrolyte adsorption onto like-charged surfaces mediated by trivalent cations.

  20. PILOT STUDY: THE TAMPA ASTHMATIC CHILDREN'S STUDY (TACS)

    EPA Science Inventory

    The Tampa Asthmatic Children's Study (TACS) was a pilot research study that focused on developing and evaluating air pollution exposure assessment methods and participant recruiting tools for children in the age range of 1-5 years old. The pilot study focused on (a) simple, cost-...

  1. QIE: performance studies of the next generation charge integrator

    NASA Astrophysics Data System (ADS)

    Roy, T.; Yumiceva, F.; Hirschauer, J.; Freeman, J.; Hughes, E.; Hare, D.; Dal Monte, L.; Whitbeck, A.; Zimmerman, T.

    2015-02-01

    The Phase 1 upgrade of the Hadron Calorimeter (HCAL) in the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC) will include two new generations (named QIE10 and QIE11) of the radiation-tolerant flash ADC chip known as the Charge Integrator and Encoder or QIE. The QIE integrates charge from a photo sensor over a 25 ns time period and encodes the result in a non-linear digital output while having a good sensitivity in both the higher and the lower energy values. The charge integrator has the advantage of analyzing fast signals coming from the calorimeters as long as the timing and pulse information is available. The calorimeters send fast, negative polarity signals, which the QIE integrates in its non-inverting input amplifier. The input analog signal enters the QIE chip through two points: signal and reference. The chip integrates the difference between these two values. This helps in getting rid of the incoming noise, which is effectively cancelled out in the difference. Over a period of about six months between September, 2013 and April, 2014 about 320 QIE10 and about 20 QIE11 chips were tested in Fermilab using a single-chip test stand where every individual chip was tested for its characteristic features using a clam-shell. The results of those tests performed on the QIE10 and QIE11 are summarized in this document.

  2. QIE: Performance Studies of the Next Generation Charge Integrator

    SciTech Connect

    Roy, T.; Yumiceva, F.; Hirschauer, J.; Freeman, J.; Hughes, E.; Hare, D.; Dal Monte, L.; Whitbeck, A.; Zimmerman, T.

    2015-02-06

    The Phase 1 upgrade of the Hadron Calorimeter (HCAL) in the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC) will include two new generations (named QIE10 and QIE11) of the radiation-tolerant flash ADC chip known as the Charge Integrator and Encoder or QIE. The QIE integrates charge from a photo sensor over a 25 ns time period and encodes the result in a non-linear digital output while having a good sensitivity in both the higher and the lower energy values. The charge integrator has the advantage of analyzing fast signals coming from the calorimeters as long as the timing and pulse information is available. The calorimeters send fast, negative polarity signals, which the QIE integrates in its non-inverting input amplifier. The input analog signal enters the QIE chip through two points: signal and reference. The chip integrates the difference between these two values. This helps in getting rid of the incoming noise, which is effectively cancelled out in the difference. Over a period of about six months between September, 2013 and April, 2014 about 320 QIE10 and about 20 QIE11 chips were tested in Fermilab using a single-chip test stand where every individual chip was tested for its characteristic features using a clam-shell. The results of those tests performed on the QIE10 and QIE11 are summarized in this document.

  3. Charge pairing of headgroups in phosphatidylcholine membranes: A molecular dynamics simulation study.

    PubMed Central

    Pasenkiewicz-Gierula, M; Takaoka, Y; Miyagawa, H; Kitamura, K; Kusumi, A

    1999-01-01

    Molecular dynamics simulation of the hydrated dimyristoylphosphatidylcholine (DMPC) bilayer membrane in the liquid-crystalline phase was carried out for 5 ns to study the interaction among DMPC headgroups in the membrane/water interface region. The phosphatidylcholine headgroup contains a positively charged choline group and negatively charged phosphate and carbonyl groups, although it is a neutral molecule as a whole. Our previous study (Pasenkiewicz-Gierula, M., Y. Takaoka, H. Miyagawa, K. Kitamura, and A. Kusumi. 1997. J. Phys. Chem. 101:3677-3691) showed the formation of water cross-bridges between negatively charged groups in which a water molecule is simultaneously hydrogen bonded to two DMPC molecules. Water bridges link 76% of DMPC molecules in the membrane. In the present study we show that relatively stable charge associations (charge pairs) are formed between the positively and negatively charged groups of two DMPC molecules. Charge pairs link 93% of DMPC molecules in the membrane. Water bridges and charge pairs together form an extended network of interactions among DMPC headgroups linking 98% of all membrane phospholipids. The average lifetimes of DMPC-DMPC associations via charge pairs, water bridges and both, are at least 730, 1400, and over 1500 ps, respectively. However, these associations are dynamic states and they break and re-form several times during their lifetime. PMID:10049307

  4. Laboratory Studies of Thermal Energy Charge Transfer of Silicon and Iron Ions in Astrophysical Plasmas

    NASA Technical Reports Server (NTRS)

    Kwong, Victor H. S.

    1996-01-01

    Charge transfer at electron-volt energies between multiply charged atomic ions and neutral atoms and molecules is of considerable importance in astrophysics, plasma physics, and in particular, fusion plasmas. In the year covered by this report, several major tasks were completed. These include: (1) the re-calibration of the ion gauge to measure the absolute particle densities of H2, He, N2, and CO for our current measurements; (2) the analysis of data for charge transfer reactions of N(exp 2 plus) ion and He, H2, N2, and CO; (3) measurement and data analysis of the charge transfer reaction of (Fe(exp 2 plus) ion and H2; (4) charge transfer measurement of Fe(exp 2 plus) ion and H2; and (5) redesign and modification of the ion detection and data acquisition system for the low energy beam facility (reflection time of flight mass spectrometer) dedicated to the study of state select charge transfer.

  5. Regional Charging Infrastructure for Plug-In Electric Vehicles: A Case Study of Massachusetts

    SciTech Connect

    Wood, Eric; Raghavan, Sesha; Rames, Clement; Eichman, Joshua; Melaina, Marc

    2017-01-01

    Given the complex issues associated with plug-in electric vehicle (PEV) charging and options in deploying charging infrastructure, there is interest in exploring scenarios of future charging infrastructure deployment to provide insight and guidance to national and regional stakeholders. The complexity and cost of PEV charging infrastructure pose challenges to decision makers, including individuals, communities, and companies considering infrastructure installations. The value of PEVs to consumers and fleet operators can be increased with well-planned and cost-effective deployment of charging infrastructure. This will increase the number of miles driven electrically and accelerate PEV market penetration, increasing the shared value of charging networks to an expanding consumer base. Given these complexities and challenges, the objective of the present study is to provide additional insight into the role of charging infrastructure in accelerating PEV market growth. To that end, existing studies on PEV infrastructure are summarized in a literature review. Next, an analysis of current markets is conducted with a focus on correlations between PEV adoption and public charging availability. A forward-looking case study is then conducted focused on supporting 300,000 PEVs by 2025 in Massachusetts. The report concludes with a discussion of potential methodology for estimating economic impacts of PEV infrastructure growth.

  6. The ethics of evaluating obesity intervention studies on children.

    PubMed

    Wickins-Drazilova, D; Williams, G

    2011-04-01

    The methodology of the IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) study raises a number of important ethical questions. Many of these are already well recognised in ethical guidelines that uphold principles of individual and parental consent, confidentiality and scientific review. There are, however, wider issues that require ethical reflection. In this paper, we focus on a set of problems surrounding the evaluation of complex social interventions, and argue that comprehensive and objective evaluation is a much more ethically charged aim than it may first appear. In particular, we contend that standard scientific measures-of body size and biomarkers-convey only part of the story. This is partly because, when we intervene in communities, we are also concerned with complex social effects. These effects are made even more complex by contemporary social anxieties about fat and physical appearance, as well as about the safety and security of children. Such anxieties increase the risk of undesirable side effects that are themselves difficult to gauge. In the face of these and other complexities, we argue that the evaluation of interventions should involve a strong ethical dimension. First, it must include-as does the IDEFICS study-consideration of the opinions of the people affected, who are subjected to interventions in ways that necessarily go beyond individual consent. Second, we suggest that interventions might also be assessed by how much they empower people-and especially those persons, such as children, who are otherwise often disempowered.

  7. Experimental studies of the charge limit phenomenon in GaAs photocathodes

    SciTech Connect

    Tang, H.; Alley, R.; Aoyagi, H.; Clendenin, J.; Saez, P.; Schultz, D.; Turner, J.

    1993-10-01

    GaAs photocathodes have been in use for generating high intensity polarized electron beams (up to a peak current of 6 A in 2 ns pulses) for the SLC high energy physics program. If the quantum efficiency (measured at low light intensities) of a GaAs photocathode is below a certain level, the maximum photoemitted charge is found to be limited by the intrinsic properties of the cathode instead of by the space charge limit. We have studied this charge limit phenomenon in a variety of GaAs photocathodes. The effects of the quantum efficiency, excitation laser wavelength, and extraction electric field on the charge limit have been examined. The temporal behavior of the charge limit as manifested in both intrapulse and interpulse effects has also been studied. These results will be discussed in light of possible mechanisms.

  8. Camera memory study for large space telescope. [charge coupled devices

    NASA Technical Reports Server (NTRS)

    Hoffman, C. P.; Brewer, J. E.; Brager, E. A.; Farnsworth, D. L.

    1975-01-01

    Specifications were developed for a memory system to be used as the storage media for camera detectors on the large space telescope (LST) satellite. Detectors with limited internal storage time such as intensities charge coupled devices and silicon intensified targets are implied. The general characteristics are reported of different approaches to the memory system with comparisons made within the guidelines set forth for the LST application. Priority ordering of comparisons is on the basis of cost, reliability, power, and physical characteristics. Specific rationales are provided for the rejection of unsuitable memory technologies. A recommended technology was selected and used to establish specifications for a breadboard memory. Procurement scheduling is provided for delivery of system breadboards in 1976, prototypes in 1978, and space qualified units in 1980.

  9. Ionization efficiency studies with charge breeder and conventional electron cyclotron resonance ion source

    SciTech Connect

    Koivisto, H. Tarvainen, O.; Toivanen, V.; Komppula, J.; Kronholm, R.; Lamy, T.; Angot, J.; Delahaye, P.; Maunoury, L.; Patti, G.; Standylo, L.; Steczkiewicz, O.; Choinski, J.

    2014-02-15

    Radioactive Ion Beams play an increasingly important role in several European research facility programs such as SPES, SPIRAL1 Upgrade, and SPIRAL2, but even more for those such as EURISOL. Although remarkable advances of ECRIS charge breeders (CBs) have been achieved, further studies are needed to gain insight on the physics of the charge breeding process. The fundamental plasma processes of charge breeders are studied in the frame of the European collaboration project, EMILIE, for optimizing the charge breeding. Important information on the charge breeding can be obtained by conducting similar experiments using the gas mixing and 2-frequency heating techniques with a conventional JYFL 14 GHz ECRIS and the LPSC-PHOENIX charge breeder. The first experiments were carried out with noble gases and they revealed, for example, that the effects of the gas mixing and 2-frequency heating on the production of high charge states appear to be additive for the conventional ECRIS. The results also indicate that at least in the case of noble gases the differences between the conventional ECRIS and the charge breeder cause only minor impact on the production efficiency of ion beams.

  10. Taking Charge: A Handbook for Parents Whose Children Have Emotional Handicaps. Second Edition.

    ERIC Educational Resources Information Center

    Kelker, Katharin A.

    This handbook was written to share the feelings, experiences, and knowledge of parents of children with emotional disturbances. The first chapter, "Feelings Come First," examines the difficulty in identifying the causes of emotional disturbances, their impact on the family, and coping strategies. The second chapter, "Finding Some Help," describes…

  11. Taking Charge: A Handbook for Parents Whose Children Have Emotional Disorders. 3rd Edition.

    ERIC Educational Resources Information Center

    Kelker, Katharin A.

    This handbook was written to share the feelings, experiences, and knowledge of parents of children with emotional disorders. The first chapter, "Feelings Come First," considers recognition of unusual behavior patterns underlying emotional disturbances and the difficulty of determining their causes, their impact on the family, and coping…

  12. A Communications Strategy for the National Children's Study

    ERIC Educational Resources Information Center

    National Institutes of Health, 2005

    2005-01-01

    The National Children's Study is the largest long term study of children's health and development ever to be conducted in the United States, involving 100,000 children from before birth to age 21. The Study aims to better understand the link between the environments in which children are raised and their physical and mental health and development.…

  13. Charge Transfer Dissociation (CTD) Mass Spectrometry of Peptide Cations: Study of Charge State Effects and Side-Chain Losses

    NASA Astrophysics Data System (ADS)

    Li, Pengfei; Jackson, Glen P.

    2017-01-01

    1+, 2+, and 3+ precursors of substance P and bradykinin were subjected to helium cation irradiation in a 3D ion trap mass spectrometer. Charge exchange with the helium cations produces a variety of fragment ions, the number and type of which are dependent on the charge state of the precursor ions. For 1+ peptide precursors, fragmentation is generally restricted to C-CO backbone bonds (a and x ions), whereas for 2+ and 3+ peptide precursors, all three backbone bonds (C-CO, C-N, and N-Cα) are cleaved. The type of backbone bond cleavage is indicative of possible dissociation channels involved in CTD process, including high-energy, kinetic-based, and ETD-like pathways. In addition to backbone cleavages, amino acid side-chain cleavages are observed in CTD, which are consistent with other high-energy and radical-mediated techniques. The unique dissociation pattern and supplementary information available from side-chain cleavages make CTD a potentially useful activation method for the structural study of gas-phase biomolecules.

  14. Children's Fitness Testing: A Feasibility Study

    ERIC Educational Resources Information Center

    Harris, J.; Cale, L.

    2007-01-01

    Objective: This study aimed to determine whether it was necessary, cost effective and practical to investigate Welsh children's fitness levels in order to promote active, healthy lifestyles. Design: A multi-method study comprising a comprehensive review of literature, a questionnaire survey and interviews. Setting: This was a feasibility study…

  15. Experimental studies of the charge limit phenomenon in NEA GaAs photocathodes

    SciTech Connect

    Tang, H.; Alley, R.K.; Aoyagi, H.; Clendenin, J.E.; Frisch, J.C.; Mulhollan, G.A.; Saez, P.J.; Schultz, D.C.; Turner, J.L.

    1994-06-01

    Negative electron affinity GaAs photocathodes have been in continuous use at SLAC for generating polarized electron beams since early 1992. If the quantum efficiency of a GaAs cathode is below a critical value, the maximum photoemitted charge with photons of energies close to the band gap in a 2-ns pulse is found to be limited by the intrinsic properties of the cathode instead of by the space charge limit. We have studied this novel charge limit phenomenon in a variety of GaAs photocathodes of different structures and doping densities. We find that the charge limit is strongly dependent on the cathode`s quantum efficiency and the extraction electric field, and to a lesser degree on the excitation laser wavelength. In addition, we show that the temporal behavior of the charge limit depends critically on the doping density.

  16. A study of short test and charge retention test methods for nickel-cadmium spacecraft cells

    NASA Technical Reports Server (NTRS)

    Scott, W. R.

    1975-01-01

    Methods for testing nickel-cadmium cells for internal shorts and charge retention were studied. Included were (a) open circuit voltage decay after a brief charge, (b) open circuit voltage recovery after shorting, and (c) open circuit voltage decay and capacity loss after a full charge. The investigation included consideration of the effects of prior history, of conditioning cells prior to testing, and of various test method variables on the results of the tests. Sensitivity of the tests was calibrated in terms of equivalent external resistance. The results were correlated. It was shown that a large number of variables may affect the results of these tests. It is concluded that the voltage decay after a brief charge and the voltage recovery methods are more sensitive than the charged stand method, and can detect an internal short equivalent to a resistance of about (10,000/C)ohms where "C' is the numerical value of the capacity of the cell in ampere hours.

  17. Thermodynamic studies on charge-coupled substituted synthetic monazite

    NASA Astrophysics Data System (ADS)

    Rawat, D.; Phapale, S.; Mishra, R.; Dash, S.

    2017-04-01

    Phosphate-based monazite ceramic is considered worldwide as a potential crystalline host matrix for immobilization of long-lived tri- and tetra-valent actinides present in high-level nuclear waste. Monazite is chemically stable with respect to the leaching processes and has high radiation stability. The present paper describes the influence of charged coupled (Ca2+, Th4+) substitution in place of La3+ on thermodynamic stability of synthetic monazite ceramics. XRD-analysis of Ca, Th substituted LaPO4 viz., La1-xCax/2Thx/2PO4 (0 ≤ x ≤ 1) points to the formation of ideal solid-solution in the entire range of composition. However, thermodynamic analysis indicates deviation from ideal solid-solution with a minima at x = 0.25. The substituted La1-xCax/2Thx/2PO4 system is found to be iso-entropic and stabilized mainly by enthalpy. Enthalpies of formation as a function of Ca2+, Th4+ substitution were analysed to provide insights into the development of thermodynamically stable nuclear waste matrix.

  18. Nanoscale study of perovskite solar cells for efficient charge transport

    NASA Astrophysics Data System (ADS)

    Adhikari, Nirmal

    The effect of temperature, humidity and water on the grain boundary potential and charge transport within the grains of pervoskite films prepared by sequential deposition technique. Grain boundary potential of perovskite films exhibited variation in electrical properties with humidity level, temperature and water concentration in methyl ammonium iodide solution. X-ray diffraction (XRD) indicates the formation of PbI2 phase in perovskite film with increasing temperature, humidity and adding larger quantity of water in methyl ammonium iodide solution. It is found that optimum amount of lead iodide helps for the passivation of perovskite film. Spatial mapping of surface potential in the perovskite film exhibits higher positive potential at grain boundaries compared to the surface of the grains. Back recombination barrier between TiO2- perovskite increases to 378 meV for perovskite film annealed at 100 ºC for 15 min. Grain boundary potential barrier were found to increase from ˜35 meV to 80 meV for perovskite film exposed to 75% RH level compared to perovskite film kept inside glove box. Optimum amount of water which increases the solar cell performance by increasing the crystallinity of perovskite film was found to be 5% by volume of IPA. Results show strong correlation between temperature, humidity level, electronic grain boundary properties and device performance of perovskite solar cells.

  19. Numerical Study of Stratified Charge Combustion in Wave Rotors

    NASA Technical Reports Server (NTRS)

    Nalim, M. Razi

    1997-01-01

    A wave rotor may be used as a pressure-gain combustor effecting non-steady flow, and intermittent, confined combustion to enhance gas turbine engine performance. It will be more compact and probably lighter than an equivalent pressure-exchange wave rotor, yet will have similar thermodynamic and mechanical characteristics. Because the allowable turbine blade temperature limits overall fuel/air ratio to sub-flammable values, premixed stratification techniques are necessary to burn hydrocarbon fuels in small engines with compressor discharge temperature well below autoignition conditions. One-dimensional, unsteady numerical simulations of stratified-charge combustion are performed using an eddy-diffusivity turbulence model and a simple reaction model incorporating a flammability limit temperature. For good combustion efficiency, a stratification strategy is developed which concentrates fuel at the leading and trailing edges of the inlet port. Rotor and exhaust temperature profiles and performance predictions are presented at three representative operating conditions of the engine: full design load, 40% load, and idle. The results indicate that peak local gas temperatures will result in excessive temperatures within the rotor housing unless additional cooling methods are used. The rotor itself will have acceptable temperatures, but the pattern factor presented to the turbine may be of concern, depending on exhaust duct design and duct-rotor interaction.

  20. Pathways to Language: A Naturalistic Study of Children with Williams Syndrome and Children with Down Syndrome

    ERIC Educational Resources Information Center

    Levy, Yonata; Eilam, Ariela

    2013-01-01

    This is a naturalistic study of the development of language in Hebrew-speaking children with Williams syndrome (WS) and children with Down syndrome (DS), whose MLU extended from 1[multiplied by]0 to 4[multiplied by]4. Developmental curves over the entire span of data collection revealed minor differences between children with WS, children with DS,…

  1. Russia's Unwanted Children: A Cultural Anthropological Study of Marginalized Children in Moscow and St. Petersburg.

    ERIC Educational Resources Information Center

    Creuziger, Clementine G. K.

    1997-01-01

    Studied the plight of marginalized children in urban Russia, including orphans, children with some family ties living in group homes, and street children. Found that changing public views toward these groups since WWII have led to a deterioration in lifestyle for these children, further contributing to criminal activity and poverty in urban areas.…

  2. Young Children's Perceptions of Scientists: A Preliminary Study

    ERIC Educational Resources Information Center

    Buldu, Mehmet

    2006-01-01

    Background: Since the 1950s, there has been a growing body of research dealing with perceptions children have of scientists. Typically, research studies in this area have utilized children's drawings in an effort to discern what those perceptions are. Studies assessing perceptions children have of scientists have shown that children have…

  3. Recent Results from a Laboratory Study of Charging Mechanisms in a Dusty Plasma

    NASA Technical Reports Server (NTRS)

    Venturini, Catherine C.; Spann, James F., Jr.; Comfort, Richard H.

    1998-01-01

    A laboratory investigation has been developed to experimentally study the interaction of micron sized particles with plasmas and electromagnetic radiation. The intent is to investigate under what conditions particles of various compositions and sizes become charged, or discharged, while exposed to an electron beam and UV radiation. This investigation uses a unique laboratory technique known as electrodynamic suspension of particles. Here, a single charged micron size particle is suspended in a quadrupole trap and then subjected to a controlled environment. In this paper, we will discuss recent results from this experiment in which different materials including polystyrene and aluminum oxide, and sizes ranging from 10 microns to 1 micron have been used to determine charge to mass ratios and then subjected to an electron beam and /or UV radiation. In each instance, the particle's charge as well as beam current flux and radiation intensity flux is measured. These results will be compared with initial results using salt crystals. It was found that a negatively charged salt crystal exposed for 30 minutes to a 500 eV electron beam with primary electron beam current of -3.06 x 10(exp -5) picoamps yielded a secondary electron current of 3.23 x 10(exp -5) picoamps. Additionally, the particle was observed to be steadily losing charge over this time interval. By studying the microphysics of one particle, a better understanding of theoretical models and other laboratory results associated with particle charging mechanisms can be achieved.

  4. Trapping-charging ability and electrical properties study of amorphous insulator by dielectric spectroscopy

    SciTech Connect

    Mekni, Omar Arifa, Hakim; Askri, Besma; Yangui, Béchir; Raouadi, Khaled; Damamme, Gilles

    2014-09-14

    Usually, the trapping phenomenon in insulating materials is studied by injecting charges using a Scanning Electron Microscope. In this work, we use the dielectric spectroscopy technique for showing a correlation between the dielectric properties and the trapping-charging ability of insulating materials. The evolution of the complex permittivity (real and imaginary parts) as a function of frequency and temperature reveals different types of relaxation according to the trapping ability of the material. We found that the space charge relaxation at low frequencies affects the real part of the complex permittivity ε{sup ´} and the dissipation factor Tan(δ). We prove that the evolution of the imaginary part of the complex permittivity against temperature ε{sup ′′}=f(T) reflects the phenomenon of charge trapping and detrapping as well as trapped charge evolution Q{sub p}(T). We also use the electric modulus formalism to better identify the space charge relaxation. The investigation of trapping or conductive nature of insulating materials was mainly made by studying the activation energy and conductivity. The conduction and trapping parameters are determined using the Correlated Barrier Hopping (CBH) model in order to confirm the relation between electrical properties and charge trapping ability.

  5. A Charge Separation Study to Enable the Design of a Complete Muon Cooling Channel

    SciTech Connect

    Yoshikawa, C.; Ankenbrandt, Charles M.; Johnson, Rolland P.; Derbenev, Yaroslav; Morozov, Vasiliy; Neuffer, David; Yonehara, K.

    2013-12-01

    The most promising designs for 6D muon cooling channels operate on a specific sign of electric charge. In particular, the Helical Cooling Channel (HCC) and Rectilinear RFOFO designs are the leading candidates to become the baseline 6D cooling channel in the Muon Accelerator Program (MAP). Time constraints prevented the design of a realistic charge separator, so a simplified study was performed to emulate the effects of charge separation on muons exiting the front end of a muon collider. The output of the study provides particle distributions that the competing designs will use as input into their cooling channels. We report here on the study of the charge separator that created the simulated particles.

  6. Simulation study of spheroidal dust gains charging: Applicable to dust grain alignment

    SciTech Connect

    Zahed, H.; Sobhanian, S.; Mahmoodi, J.; Khorram, S.

    2006-09-15

    The charging process of nonspherical dust grains in an unmagnetized plasma as well as in the presence of a magnetic field is studied. It is shown that unlike the spherical dust grain, due to nonhomogeneity of charge distribution on the spheroidal dust surface, the resultant electric forces on electrons and ions are different. This process produces some surface charge density gradient on the nonspherical grain surface. Effects of a magnetic field and other plasma parameters on the properties of the dust particulate are studied. It has been shown that the alignment direction could be changed or even reversed with the magnetic field and plasma parameters. Finally, the charge distribution on the spheroidal grain surface is studied for different ambient parameters including plasma temperature, neutral collision frequency, and the magnitude of the magnetic field.

  7. Study of television viewing habits in children.

    PubMed

    Mukherjee, Sharmila Banerjee; Gupta, Yogita; Aneja, Satinder

    2014-11-01

    Previous studies from developing countries have reported that Television (TV) viewing, if excessive and of poor quality has a proven negative influence on child health. Indian studies on this subject are few. The present study aimed at determining TV viewing habits of children and their families as well as parental perspectives on the impact of TV on child health using a provider completed indigenously developed questionnaire in Hindi. The study group comprised of 109 children attending a government hospital who belonged predominantly to lower socio-economic strata with poor maternal literacy. It was observed that 100 % children watched excessive TV (> 2 h daily), with majority viewing unsupervised and low quality content. There were minimal parental restrictions and no active discussion regarding contents. Negative impact was found on play, hobbies, sleep hygiene and eating habits in most children. Most parents were unaware of unhealthy viewing and the associated deleterious effects. As pediatricians we need to enquire about TV viewing habits routinely and educate parents about appropriate TV viewing.

  8. Poor Rural Children Attract Close Study

    ERIC Educational Resources Information Center

    Viadero, Debra

    2008-01-01

    Growing up poor in isolated rural areas and small towns is qualitatively different from growing up poor in the city. Yet most of what experts know about the effects of poverty on children's development comes from studies conducted in big cities. Now, an ambitious project run by universities in Pennsylvania and North Carolina is putting what some…

  9. Children with Lesbian Parents: A Community Study.

    ERIC Educational Resources Information Center

    Golombok, Susan; Perry, Beth; Burston, Amanda; Murray, Clare; Mooney-Somers, Julid; Stevens, Madeleine; Golding, Jean

    2003-01-01

    Examined the quality of parent-child relationships and the socioemotional and gender development of a community sample of 7-year-olds with lesbian parents, with two-parent heterosexual parents, or with single heterosexual mothers from the Avon Longitudinal Study of Parents and Children. Found no significant differences between lesbian mothers and…

  10. Study of a lithium-ion battery charge-discharge test unit characteristics*

    NASA Astrophysics Data System (ADS)

    Kopylov, E. A.; Mizrah, E. A.; Fedchenko, A. S.; Lobanov, D. K.

    2016-04-01

    The article describes the structure of a charge-discharge unit which allows to perform electrical, resource and thermal testing of several lithium-ion batteries simultaneously. The principle of operation of a one battery research channel (BRC) is shown. This study evaluated the stabilization error and rate of change of charge/discharge currents, the switching time from the charge mode to the discharge mode and vice versa for a single BRC and parallel BRCs. The possibility of increasing the maximum battery testing current due to the parallel connection of multiple BRCs without using a current alignment device between channels was discussed.

  11. Understanding charge transfer processes on metal oxides: a laser-flash-photolysis study

    NASA Astrophysics Data System (ADS)

    Sieland, Fabian; Schneider, Jenny; Lippmann, Thorsten; Bahnemann, Detlef W.

    2016-09-01

    In the focus of this study, mixtures of commercially available TiO2 powders were created and their photocatalytic activity concerning the acetaldehyde degradation in the gas phase was tested. Further, the lifetime of the photogenerated charge carriers was analyzed by Laser-Flash-Photolysis-Spectroscopy. The acetaldehyde degradation experiments of the mixed powders lead to positive and negative deviations from the expected weighted mean. Nevertheless, their photocatalytic activity could be correlated with the lifetime of the charge carriers. A longer charge carrier lifetime at ambient conditions correlated with a lower fractional conversion of acetaldehyde. The advantageous activities of the samples were associated with a charge transfer reaction between larger and smaller particles comparable to the antenna mechanism.1

  12. STUDIES OF X-RAY PRODUCTION FOLLOWING CHARGE EXCHANGE RECOMBINATION BETWEEN HIGHLY CHARGED IONS AND NEUTRAL ATOMS AND MOLECULES

    SciTech Connect

    Brown, G V; Beiersdorfer, P; Chen, H; Clementson, J; Frankel, M; Gu, M F; Kelley, R L; Kilbourne, C A; Porter, F S; Thorn, D B; Wargelin, B J

    2008-08-28

    We have used microcalorimeters built by the NASA/Goddard Space Flight Center and the Lawrence Livermore National Laboratory Electron Beam Ion Trap to measure X-ray emission produced by charge exchange reactions between highly charged ions colliding with neutral helium, hydrogen, and nitrogen gas. Our measurements show the spectral dependence on neutral species and also show the distinct differences between spectra produced by charge exchange reactions and those produced by direct impact excitation. These results are part of an ongoing experimental investigation at the LLNL EBIT facility of charge exchange spectral signatures and can be used to interpret X-ray spectra produced by a variety of laboratory and celestial sources including cometary and planetary atmospheres, the Earth's magnetosheath, the heliosphere, and tokamaks.

  13. Spontaneous Mass and Charge Losses from Single Multi-Megadalton Ions Studied by Charge Detection Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Keifer, David Z.; Alexander, Andrew W.; Jarrold, Martin F.

    2017-01-01

    Spontaneous mass and charge losses from individual multi-megadalton ions have been observed with charge detection mass spectrometry (CDMS) by trapping single hepatitis B virus (HBV) capsids for 3 s. Gradual increases in the oscillation frequency of single ions in the ion trap are attributed mainly to mass loss (probably solvent, water, and/or salt). The total mass lost during the 3 s trapping period peaks at around 20 kDa for 4 MDa HBV T = 4 capsids. Discrete frequency drops punctuate the gradual increases in the oscillation frequencies. The drops are attributed to a sudden loss of charge. In most cases a single positive charge is lost along with some mass (on average around 1000 Da). Charge loss occurs for over 40% of the trapped ions. It usually occurs near the beginning of the trapping event, and it occurs preferentially in regions of the trap with strong electric fields, indicating that external electric fields promote charge loss. This process may contribute to the decrease in m/z resolution that often occurs with megadalton ions.

  14. Spontaneous Mass and Charge Losses from Single Multi-Megadalton Ions Studied by Charge Detection Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Keifer, David Z.; Alexander, Andrew W.; Jarrold, Martin F.

    2017-03-01

    Spontaneous mass and charge losses from individual multi-megadalton ions have been observed with charge detection mass spectrometry (CDMS) by trapping single hepatitis B virus (HBV) capsids for 3 s. Gradual increases in the oscillation frequency of single ions in the ion trap are attributed mainly to mass loss (probably solvent, water, and/or salt). The total mass lost during the 3 s trapping period peaks at around 20 kDa for 4 MDa HBV T = 4 capsids. Discrete frequency drops punctuate the gradual increases in the oscillation frequencies. The drops are attributed to a sudden loss of charge. In most cases a single positive charge is lost along with some mass (on average around 1000 Da). Charge loss occurs for over 40% of the trapped ions. It usually occurs near the beginning of the trapping event, and it occurs preferentially in regions of the trap with strong electric fields, indicating that external electric fields promote charge loss. This process may contribute to the decrease in m/ z resolution that often occurs with megadalton ions.

  15. A Detailed Study on the Low-Energy Structures of Charged Colloidal Clusters.

    PubMed

    Cruz, S M A; Marques, J M C

    2016-04-07

    The target of this investigation is the systematic characterization of the low-energy structures of charged colloidal clusters that may be important to understand the self-assembling process of biomolecules. The aggregation of charged colloidal particles is governed by the attractive short-ranged Morse potential and the Yukawa repulsive tail to describe the long-range charge effect. A global optimization strategy, based on our own evolutionary algorithm, was adopted to discover the low-energy structures of colloidal clusters composed of up to 20 particles. A detailed analysis of the low-energy structures involving charged particles shows that the appearance of the Bernal spiral as the most stable motif occurs, first, at N = 6, but it is favored for larger clusters (N ≥ 13); for 6 ≤ N ≤ 12, there is a competition between the spiral (which is favored for higher charges) and more spherical-like structures. Finally, we study binary clusters composed by two sets of differently charged colloidal particles. Although a great diversity of low-energy structures is observed (especially for aggregates with one of the components in excess), the global minimum is disputed by three structural motifs depending on the composition of the cluster and, in some cases, on the range of the Morse potential.

  16. A Reflective Study into Children's Cognition When Making Computer Games

    ERIC Educational Resources Information Center

    Allsop, Yasemin

    2016-01-01

    In this paper, children's mental activities when making digital games are explored. Where previous studies have mainly focused on children's learning, this study aimed to unfold the children's thinking process for learning when making computer games. As part of an ongoing larger scale study, which adopts an ethnographic approach, this research…

  17. Studies on plasma profiles and its effect on dust charging in hydrogen plasma

    NASA Astrophysics Data System (ADS)

    Kakati, B.; Kausik, S. S.; Saikia, B. K.; Bandyopadhay, M.

    2010-02-01

    Plasma profiles and its influence on dust charging are studied in hydrogen plasma. The plasma is produced in a high vacuum device by a hot cathode discharge method and is confined by a cusped magnetic field cage. A cylindrical Espion advanced Langmuir probe having 0.15 mm diameter and 10.0 mm length is used to study the plasma parameters for various discharge conditions. Optimum operational discharge parameters in terms of charging of the dust grains are studied. The charge on the surface of the dust particle is calculated from the capacitance model and the current by the dust grains is measured by the combination of a Faraday cup and an electrometer. Unlike our previous experiments in which dust grains were produced in-situ, here a dust dropper is used to drop the dust particles into the plasma.

  18. MAOA, DBH and SLC6A4 variants in CHARGE: A case control study of autism spectrum disorders

    PubMed Central

    Tassone, Flora; Qi, Lihong; Zhang, Wenting; Hansen, Robin L; Pessah, Isaac N; Hertz-Picciotto, Irva

    2011-01-01

    Background Genetic factors are established to contribute to the development of autism. We examined three loci, serotonin transporter (SLC6A4), dopamine hydroxylase (DBH) and the variable number of tandem repeat promoter of the monoamine oxidase A (MAOA) for association with autism in participants from the CHARGE (CHildhood Autism Risks from Genetics and the Environment) Study, the first large-scale population-based case-control investigation of both environmental and genetic contributions to autism risk. Methods Among male children enrolled in the CHARGE study we tested associations between each of the three polymorphisms and autism (AU) (n=119), or a combined group of autism and other autism spectrum disorders (AU+ASD, which includes an additional n=53) as compared with typically developing controls (TD, n=137). Results The case-control association analysis showed neither SLC6A4 nor DBH to be statistically significantly associated with AU or ASD. However, the male children carrying 4 tandem repeats in the promoter region of the MAOA gene showed a 2-fold higher risk of AU (or AU+ASD) than those carrying allele 3, adjusted for confounders (OR = 2.02, 95% CI = 1.12, 3.65, p = 0.02 for AU vs. TD, and OR = 2.05, 95% CI = 1.19, 3.53, p = 0.01 for ASD vs. TD). In addition, mothers homozygous for the 4 tandem repeat allele showed at least a 3-fold higher risk of AU (or AU+ASD) than mothers homozygous for allele 3 (OR = 3.07, 95% CI = 1.19, 7.91, p = 0.02 for AU vs. TD, and OR = 3.26, 95% CI = 1.35, 7.89, p = 0.009 for AU+ASD vs. TD). Conclusions These results suggest a potential role of the functional MAOA promoter alleles in the male child, the mother, or both in autism spectrum disorders. PMID:21538940

  19. A Snapshot of Young Children's Mathematical Competencies: Results from the Longitudinal Study of Australian Children

    ERIC Educational Resources Information Center

    MacDonald, Amy; Carmichael, Colin

    2015-01-01

    This article presents a snapshot of the mathematical competencies of children aged four to five years in Australian early childhood education settings, as perceived by their educators. Data are presented from a nationally-representative sample of 6511 children participating in the Longitudinal Study of Australian Children (LSAC). The results…

  20. Gender, Parental Beliefs and Children's Mathematics Performance: Insights from the Longitudinal Study of Australian Children

    ERIC Educational Resources Information Center

    Carmichael, Colin

    2014-01-01

    With reports of declining participation in mathematics related careers and low female participation rates, the issue of gender differences in mathematics remains relevant. This study seeks to examine the relationship between: children's sex, parents' beliefs regarding their children's education, and, the children's mathematics performance. Through…

  1. Listening to Children: Exploring Intuitive Strategies and Interactive Methods in a Study of Children's Special Places

    ERIC Educational Resources Information Center

    Green, Carie

    2012-01-01

    Stemming from the UNCRC, childhood researchers have proposed a variety of methodological strategies for upholding children's rights and understanding their perspectives. This paper aims to advance the conversation on engaging children's perspectives by presenting data collection methods used in a qualitative study exploring children's special…

  2. CONSIDERATION OF CHILDREN'S DISTINCTIVE SUSCEPTIBILITY IN ENVIRONMENTAL HEALTH STUDIES

    EPA Science Inventory

    Consideration of children's distinctive susceptibility in environmental health studies.
    Pauline Mendola (US EPA, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC 27711)

    Children are a particularly susceptible subpopulation with ...

  3. Recent Studies on Feeding Problems in Children with Autism

    ERIC Educational Resources Information Center

    Volkert, Valerie M.; Vaz, Petula C. M.

    2010-01-01

    This paper reviews recent studies on behavioral interventions for children with autism and feeding problems. The applicability of interventions that have been tested with other populations of children with feeding problems is discussed, as well as directions for future research.

  4. Study of charge-sharing in MEDIPIX3 using a micro-focused synchrotron beam

    NASA Astrophysics Data System (ADS)

    Gimenez, E. N.; Ballabriga, R.; Campbell, M.; Horswell, I.; Llopart, X.; Marchal, J.; Sawhney, K. J. S.; Tartoni, N.; Turecek, D.

    2011-01-01

    X-ray photon-counting detectors consisting of a silicon pixel array sensor bump-bonded to a CMOS electronic readout chip offer several advantages over traditional X-ray detection technologies used for synchrotron applications. They offer high frame rate, dynamic range, count rate capability and signal-to-noise ratio. A survey of the requirements for future synchrotron detectors carried out at the Diamond Light Source synchrotron highlighted the needs for detectors with a pixel size of the order of 50μm. Reducing the pixel size leads to an increase of charge-sharing events between adjacent pixels and, therefore, to a degradation of the energy resolution and image quality of the detector. This effect was observed with MEDIPIX2, a photon-counting readout chip with a pixel size of 55μm. The lastest generation of the MEDIPIX family, MEDIPIX3, is designed to overcome this charge-sharing effect in an implemented readout operating mode referred to as Charge Summing Mode. MEDIPIX3 has the same pixel size as MEDIPIX2, but it is implemented in an 8-metal 0.13μm CMOS technology which enables increased functionality per pixel. The present work focuses on the study of the charge-sharing effect when the MEDIPIX3 is operated in Charge Summing Mode compared to the conventional readout mode, referred to as Single Pixel Mode. Tests of a standard silicon photodiode array bump-bonded to MEDIPIX3 were performed in beamline B16 at the Diamond Light Source synchrotron. A monochromatic micro-focused beam of 2.9μm x 2.2μm size at 15keV was used to scan a cluster of nine pixels in order to study the charge collection and X-ray count allocation process for each readout mode, Single Pixel Mode and Charge Summing Mode. The study showed that charge-shared events were eliminated when Medipix3 was operated in Charge Summing Mode.

  5. Charge-magnetic interference resonant scattering studies of ferromagnetic crystals and thin films

    SciTech Connect

    Haskel, D.; Kravtsov, E.; Choi, Y.; Lang, J.C.; Islam, Z.; Srajer, G.; Jiang, J.S.; Bader, S.D.; Canfield, Paul C.

    2012-06-15

    The element- and site-specificity of X-ray resonant magnetic scattering (XRMS) makes it an ideal tool for furthering our understanding of complex magnetic systems. In the hard X-rays, XRMS is readily applied to most antiferromagnets where the relatively weak resonant magnetic scattering (10 −2–10 −6Ic) is separated in reciprocal space from the stronger, Bragg charge scattered intensity, Ic. In ferro(ferri)magnetic materials, however, such separation does not occur and measurements of resonant magnetic scattering in the presence of strong charge scattering are quite challenging. We discuss the use of charge-magnetic interference resonant scattering for studies of ferromagnetic (FM) crystals and layered films. We review the challenges and opportunities afforded by this approach, particularly when using circularly polarized X-rays.We illustrate current capabilities at the Advanced Photon Source with studies aimed at probing site-specific magnetism in ferromagnetic crystals, and interfacial magnetism in films.

  6. A Comparative Study of Power Supply Architectures In Wireless Electric Vehicle Charging Systems

    NASA Astrophysics Data System (ADS)

    Esteban, Bryan

    Wireless inductive power transfer is a transformational and disruptive technology that enables the reliable and efficient transfer of electrical power over large air gaps for a host of unique applications. One such application that is now gaining much momentum worldwide is the wireless charging of electric vehicles (EVs). This thesis examines two of the primary power supply topologies being predominantly used for EV charging, namely the SLC and the LCL resonant full bridge inverter topologies. The study of both of these topologies is presented in the context of designing a 3 kW, primary side controlled, wireless EV charger with nominal operating parameters of 30 kHz centre frequency and range of coupling in the neighborhood of .18-.26. A comparison of both topologies is made in terms of their complexity, cost, efficiency, and power quality. The aim of the study is to determine which topology is better for wireless EV charging.

  7. Laboratory Studies of Thermal Energy Charge Transfer of Silicon and Iron Ions in Astrophysical Plasmas

    NASA Technical Reports Server (NTRS)

    Kwong, Victor H. S.

    1997-01-01

    The laser ablation/ion storage facility at the UNLV Physics Department is dedicated to the study of atomic processes in low temperature plasmas. Our current program is directed to the study of charge transfer of multiply charged ions and neutrals that are of importance to astrophysics at energies less than 1 eV (about 10(exp 4) K). Specifically, we measure the charge transfer rate coefficient of ions such as N(2+), Si(3+), Si(3+), with helium and Fe(2+) with molecular and atomic hydrogen. All these ions are found in a variety of astrophysical plasmas. Their electron transfer reactions with neutral atoms can affect the ionization equilibrium of the plasma.

  8. Charge heterogeneity study of a Fc-fusion protein, abatacept, using two-dimensional gel electrophoresis.

    PubMed

    Nebija, D; Noe, C R; Lachmann, B

    2015-08-01

    Medicinal products obtained by recombinant DNA technology are complex molecules and demonstrate a high degree of molecular heterogeneity. Charge heterogeneity and isoform pattern of this class of medicines, are parameters important for their quality, safety, and efficacy. In this study we report the application of two-dimensional gel electrophoresis (2-D electrophoresis) for the quality assessment, identification, charge heterogeneity and isoform pattern study of recombinant protein, CTLA4-Ig (abatacept), which has been selected as an example of the drug class, known as Fc-fusion proteins. In order to achieve an efficient separation of this complex analyte,2-D electrophoresis was optimized employing different experimental conditions regarding the selection of an immobilized pH gradient (IPG), sample pretreatment, presentation and detection procedure. Experimental datadocumented that 2-D electrophoresis is a suitable method for the assessment of identity, purity, structural integrity, isoform pattern and to monitor charge heterogeneity and post-translational glycosylation of the Fc-fusion protein, abatacept.

  9. Clinical study on the treatment of chronic wound with negatively-charged aerosol

    PubMed Central

    Xie, Xiaoxia; Chen, Lei; Zhang, Zhao-Qiang; Shi, Yan; Xie, Julin

    2013-01-01

    Background: Aerosols are defined as the mixture of liquid or solid particles/droplets that are stably suspending in air. When carrying a certain amount of negative charge, they will be defined as negatively-charged aerosol. This report investigates the effect of negatively-charged aerosol on the healing of chronic wound. Methods: 140 patients with chronic wound were assigned randomly into two groups. Normal, routine treatment was applied on chronic wounds of 73 patients depending on wounds situation (control group). While another 67 similar patients received negatively-charged aerosol therapy (2 hours per time, twice a day) and were used as experimental group. Wound healing assessment including the patients’ complication, detection of bacteria in wound secretions, and evaluation of wound healing. Results: The results of our study showed that after the application of negatively-charged aerosols, and condition and infection rate of wounds from experiment group were better and lower than that of control group. In comparison with control group, the relative size of wounds from experiment group was significantly smaller (P<0.05) at post-treatment day 0, 7, 14, 21 and 28. Also, the time required for wound healing in the experimental group was significantly shorter (P<0.05) than that in the control group. Conclusion: Negatively-charged aerosol therapy can accelerate wound healing speed and improve the healing of chronic wounds. Thus, we wound recommend the consideration of Negatively-charged aerosol therapies in addition to normal wound treatment in cases of chronic wound. PMID:24040472

  10. A new charge-tagged proline-based organocatalyst for mechanistic studies using electrospray mass spectrometry

    PubMed Central

    Willms, J Alexander; Beel, Rita; Schmidt, Martin L; Mundt, Christian

    2014-01-01

    Summary A new 4-hydroxy-L-proline derivative with a charged 1-ethylpyridinium-4-phenoxy substituent has been synthesized with the aim of facilitating mechanistic studies of proline-catalyzed reactions by ESI mass spectrometry. The charged residue ensures a strongly enhanced ESI response compared to neutral unmodified proline. The connection by a rigid linker fixes the position of the charge tag far away from the catalytic center in order to avoid unwanted interactions. The use of a charged catalyst leads to significantly enhanced ESI signal abundances for every catalyst-derived species which are the ones of highest interest present in a reacting solution. The new charged proline catalyst has been tested in the direct asymmetric inverse aldol reaction between aldehydes and diethyl ketomalonate. Two intermediates in accordance with the List–Houk mechanism for enamine catalysis have been detected and characterized by gas-phase fragmentation. In addition, their temporal evolution has been followed using a microreactor continuous-flow technique. PMID:25246962

  11. Study of surface charge density on solid/liquid interfaces by modulating the electrical double layer

    NASA Astrophysics Data System (ADS)

    Pak, Hyuk Kyu; Moon, Jong Kyun

    2014-11-01

    A solid surface in contact with water or aqueous solution usually carries specific electric charges. These surface charges attract counter ions from the liquid side. Since the geometry of opposite charge distribution parallel to the solid/liquid interface is similar to that of a capacitor, it is called an electrical double layer capacitor (EDLC). Therefore, there is an electrical potential difference across an EDLC in equilibrium. When a liquid bridge is formed between two conducting plates, the system behaves as two serially connected EDLCs. In this work, we propose a new method for investigating the surface charge density on solid/liquid interfaces. By mechanically modulating the electrical double layers and simultaneously applying a DC bias voltage across the plates, an AC electric current can be generated. By measuring the voltage difference between the plates as a function of bias voltage, we can study the surface charge density on solid/liquid interfaces. Our experimental results agree very well with the simple equivalent circuit model proposed here. Furthermore, using this method, one can determine the polarity of the adsorbed state on the solid surface depending on the material used. This work was supported by Center for Soft and Living Matter through IBS program in Korea.

  12. Resistive Micromegas for sampling calorimetry, a study of charge-up effects

    NASA Astrophysics Data System (ADS)

    Chefdeville, M.; Karyotakis, Y.; Geralis, T.; Titov, M.

    2016-07-01

    Micromegas, as a proportional and compact gaseous detector, is well suited for sampling calorimetry. The limitation of occasional sparking has now been lifted by means of resistive electrodes but at the cost of current-dependent charge-up effects. These effects are studied in this contribution, with an emphasis on gain variations during operation at high particle rate and under heavy ionisation. Results are reproduced by a simple model of charging-up which will be used for detector design optimisation in the future.

  13. CPIC: A Parallel Particle-In-Cell Code for Studying Spacecraft Charging

    NASA Astrophysics Data System (ADS)

    Meierbachtol, Collin; Delzanno, Gian Luca; Moulton, David; Vernon, Louis

    2015-11-01

    CPIC is a three-dimensional electrostatic particle-in-cell code designed for use with curvilinear meshes. One of its primary objectives is to aid in studying spacecraft charging in the magnetosphere. CPIC maintains near-optimal computational performance and scaling thanks to a mapped logical mesh field solver, and a hybrid physical-logical space particle mover (avoiding the need to track particles). CPIC is written for parallel execution, utilizing a combination of both OpenMP threading and MPI distributed memory. New capabilities are being actively developed and added to CPIC, including the ability to handle multi-block curvilinear mesh structures. Verification results comparing CPIC to analytic test problems will be provided. Particular emphasis will be placed on the charging and shielding of a sphere-in-plasma system. Simulated charging results of representative spacecraft geometries will also be presented. Finally, its performance capabilities will be demonstrated through parallel scaling data.

  14. Spectrophotometric study of the charge-transfer complexes of iodine with antipyrine in organic solvents

    NASA Astrophysics Data System (ADS)

    Hasani, Masoumeh; Rezaei, Alireza

    2006-12-01

    The charge-transfer complex formation of iodine with antipyrine has been studied spectrophotometrically in chloroform, dichloromethane (DCM) and 1,2-dichloroethane (DCE) solutions at 25 °C. The results indicate the formation of 1:1 charge-transfer complexes. The observed time dependence of the charge-transfer band and subsequent formation of I 3- in solution were related to the slow transformation of the initially formed 1:1 antipyrine:I 2 outer complex to an inner electron donor-acceptor (EDA) complex, followed by fast reaction of the inner complex with iodine to form a triiodide ion. The values of the equilibrium constant, K, are calculated for each complex and the influence of the solvent properties on the formation of EDA complexes and the rates of subsequent reaction is evaluated.

  15. Spectrophotometric study of the charge-transfer complexes of iodine with antipyrine in organic solvents.

    PubMed

    Hasani, Masoumeh; Rezaei, Alireza

    2006-12-01

    The charge-transfer complex formation of iodine with antipyrine has been studied spectrophotometrically in chloroform, dichloromethane (DCM) and 1,2-dichloroethane (DCE) solutions at 25 degrees C. The results indicate the formation of 1:1 charge-transfer complexes. The observed time dependence of the charge-transfer band and subsequent formation of I(3)(-) in solution were related to the slow transformation of the initially formed 1:1 antipyrine:I(2) outer complex to an inner electron donor-acceptor (EDA) complex, followed by fast reaction of the inner complex with iodine to form a triiodide ion. The values of the equilibrium constant, K, are calculated for each complex and the influence of the solvent properties on the formation of EDA complexes and the rates of subsequent reaction is evaluated.

  16. A theoretical study of charge transport properties of trifluoromethyl (-CF3) substituted naphthalene (TFMNA) molecule

    NASA Astrophysics Data System (ADS)

    Sahoo, S. R.; Parida, S. K.; Sahu, S.

    2016-09-01

    We present a density functional (DFT) study of the charge transport properties of CF3-naphthalene. Nature of charge transport is investigated using parameters such as reorganization energy (X), transfer integral (t), ionization potential (IP), electron affinity (EA), and carrier mobility (μ) computed through electronic structure calculations. We observe a decrease in X and IP from 2,6-DTFMNA to 1,5-DTFMNA, whereas, the EA is found to be enhanced, as a result p-type characteristics, with mild n-type signature, in the organic semiconductor gets increased. In addition, the HOMO-LUMO gap also gets reduced inferring more charge injection through the potential barrier. The maximum hole and electron mobility values for the substituted compound are obtained to be 2.17 cm2/ Vsec & 0.20 cm2/ Vsec, respectively.

  17. Electroweak Decay Studies of Highly Charged Radioactive Ions with TITAN at TRIUMF

    NASA Astrophysics Data System (ADS)

    Leach, Kyle; Dillmann, Iris; Klawitter, Renee; Leistenschneider, Erich; Lennarz, Annika; Brunner, Thomas; Frekers, Dieter; Andreoiu, Corina; Kwiatkowski, Anna; Dilling, Jens

    2017-03-01

    Several modes of electroweak radioactive decay require an interaction between the nucleus and bound electrons within the constituent atom. Thus, the probabilities of the respective decays are not only influenced by the structure of the initial and final states in the nucleus, but can also depend strongly on the atomic charge. Conditions suitable for the partial or complete ionization of these rare isotopes occur naturally in hot, dense astrophysical environments, but can also be artificially generated in the laboratory to selectively block certain radioactive decay modes. Direct experimental studies on such scenarios are extremely difficult due to the laboratory conditions required to generate and store radioactive ions at high charge states. A new electron-beam ion trap (EBIT) decay setup with the TITAN experiment at TRIUMF has successfully demonstrated such techniques for performing spectroscopy on the radioactive decay of highly charged ions.

  18. Effect of Valence of Counterions on the Structure of Charged Membranes, a Computer Simulation Study

    NASA Astrophysics Data System (ADS)

    Qiao, Baofu; Olvera de La Cruz, Monica

    2012-02-01

    Phospholipids have been investigated for a long period, due to its ability of self-assembling into bilayer structures which resemble biological membranes. But most of the studies have been limited on the neutral phosphatidylcholine based lipids. The understanding of charged membranes (e.g., phosphatidylserine) is very limited due to the repulsion between the charged groups on lipids. In the present work, we investigated the effect of different counter-ions on the structures of charged membranes formed by 1,2-dilauroyl-sn-glycoro-3-phospho-L-serine. Three kinds of counterions were investigated, from monovalent, to divalent, to trivalent ions. Molecular dynamics simulations were performed at all-atom level. We have calculated the area per lipid. And the interaction between counterions and COO^- groups was found to dominate over that between counterions and PO4^- groups.

  19. Collaborative Study of Children Treated for Phenylketonuria: Study Design

    ERIC Educational Resources Information Center

    Williamson, Malcolm; And Others

    1977-01-01

    Available from: Arthur Retlaw and Associates, Inc., Suite 2080, 1603 Orrington Avenue, Evanston, Illinois 60201. Described is a study in which a large sample of children (n=444) with phenylketonuria (an inborn metabolic error usually related to impaired cognitive ability) were treated under controlled conditions from near birth to 6 years of age.…

  20. A nanoscale study of charge extraction in organic solar cells: the impact of interfacial molecular configurations.

    PubMed

    Tang, Fu-Ching; Wu, Fu-Chiao; Yen, Chia-Te; Chang, Jay; Chou, Wei-Yang; Gilbert Chang, Shih-Hui; Cheng, Horng-Long

    2015-01-07

    In the optimization of organic solar cells (OSCs), a key problem lies in the maximization of charge carriers from the active layer to the electrodes. Hence, this study focused on the interfacial molecular configurations in efficient OSC charge extraction by theoretical investigations and experiments, including small molecule-based bilayer-heterojunction (sm-BLHJ) and polymer-based bulk-heterojunction (p-BHJ) OSCs. We first examined a well-defined sm-BLHJ model system of OSC composed of p-type pentacene, an n-type perylene derivative, and a nanogroove-structured poly(3,4-ethylenedioxythiophene) (NS-PEDOT) hole extraction layer. The OSC with NS-PEDOT shows a 230% increment in the short circuit current density compared with that of the conventional planar PEDOT layer. Our theoretical calculations indicated that small variations in the microscopic intermolecular interaction among these interfacial configurations could induce significant differences in charge extraction efficiency. Experimentally, different interfacial configurations were generated between the photo-active layer and the nanostructured charge extraction layer with periodic nanogroove structures. In addition to pentacene, poly(3-hexylthiophene), the most commonly used electron-donor material system in p-BHJ OSCs was also explored in terms of its possible use as a photo-active layer. Local conductive atomic force microscopy was used to measure the nanoscale charge extraction efficiency at different locations within the nanogroove, thus highlighting the importance of interfacial molecular configurations in efficient charge extraction. This study enriches understanding regarding the optimization of the photovoltaic properties of several types of OSCs by conducting appropriate interfacial engineering based on organic/polymer molecular orientations. The ultimate power conversion efficiency beyond at least 15% is highly expected when the best state-of-the-art p-BHJ OSCs are combined with present arguments.

  1. NMR Study of Ion Dynamics and Charge Storage in Ionic Liquid Supercapacitors.

    PubMed

    Forse, Alexander C; Griffin, John M; Merlet, Céline; Bayley, Paul M; Wang, Hao; Simon, Patrice; Grey, Clare P

    2015-06-10

    Ionic liquids are emerging as promising new electrolytes for supercapacitors. While their higher operating voltages allow the storage of more energy than organic electrolytes, they cannot currently compete in terms of power performance. More fundamental studies of the mechanism and dynamics of charge storage are required to facilitate the development and application of these materials. Here we demonstrate the application of nuclear magnetic resonance spectroscopy to study the structure and dynamics of ionic liquids confined in porous carbon electrodes. The measurements reveal that ionic liquids spontaneously wet the carbon micropores in the absence of any applied potential and that on application of a potential supercapacitor charging takes place by adsorption of counterions and desorption of co-ions from the pores. We find that adsorption and desorption of anions surprisingly plays a more dominant role than that of the cations. Having elucidated the charging mechanism, we go on to study the factors that affect the rate of ionic diffusion in the carbon micropores in an effort to understand supercapacitor charging dynamics. We show that the line shape of the resonance arising from adsorbed ions is a sensitive probe of their effective diffusion rate, which is found to depend on the ionic liquid studied, as well as the presence of any solvent additives. Taken as whole, our NMR measurements allow us to rationalize the power performances of different electrolytes in supercapacitors.

  2. NMR Study of Ion Dynamics and Charge Storage in Ionic Liquid Supercapacitors

    PubMed Central

    2015-01-01

    Ionic liquids are emerging as promising new electrolytes for supercapacitors. While their higher operating voltages allow the storage of more energy than organic electrolytes, they cannot currently compete in terms of power performance. More fundamental studies of the mechanism and dynamics of charge storage are required to facilitate the development and application of these materials. Here we demonstrate the application of nuclear magnetic resonance spectroscopy to study the structure and dynamics of ionic liquids confined in porous carbon electrodes. The measurements reveal that ionic liquids spontaneously wet the carbon micropores in the absence of any applied potential and that on application of a potential supercapacitor charging takes place by adsorption of counterions and desorption of co-ions from the pores. We find that adsorption and desorption of anions surprisingly plays a more dominant role than that of the cations. Having elucidated the charging mechanism, we go on to study the factors that affect the rate of ionic diffusion in the carbon micropores in an effort to understand supercapacitor charging dynamics. We show that the line shape of the resonance arising from adsorbed ions is a sensitive probe of their effective diffusion rate, which is found to depend on the ionic liquid studied, as well as the presence of any solvent additives. Taken as whole, our NMR measurements allow us to rationalize the power performances of different electrolytes in supercapacitors. PMID:25973552

  3. Syntax and Prosody in Narratives: A Study of Preschool Children

    ERIC Educational Resources Information Center

    Zanchi, Paola; Zampini, Laura; Fasolo, Mirco; D'Odorico, Laura

    2016-01-01

    The present study examines narrative competence and its relationships with syntactic and prosodic skills in preschool children. The narrative skills of 30 typically developing Italian children were assessed during their first year of kindergarten attendance (T1) and again one year later (T2). A picture book was used to elicit children's…

  4. Egyptian Children's Use of Technology: A Phenomenological Study

    ERIC Educational Resources Information Center

    Morgan, Hani; Lee, Guang-Lea

    2017-01-01

    Although the use of technology can be very important for children younger than age 12 years, not all countries possess the financial resources to make digital resources widely available to students. Children can also use technology inappropriately. This study explores the consequences of exposure to different forms of technology on children. It…

  5. Psychological and Educational Studies with Spina Bifida Children. Final Report.

    ERIC Educational Resources Information Center

    Diller, Leonard; And Others

    To measure school achievements in spina bifida children, to relate these measures to certain variables, to obtain information on educational problems, and to study facets of cognition and its changes with age, 77 spina bifida children and 53 amputees (all aged 5 to 15) were tested. Sixty non-disabled children were at times used for controls. The…

  6. Ion distributions at charged aqueous surfaces: Synchrotron X-ray scattering studies

    SciTech Connect

    Bu, Wei

    2009-01-01

    Surface sensitive synchrotron X-ray scattering studies were performed to obtain the distribution of monovalent ions next to a highly charged interface at room temperature. To control surface charge density, lipids, dihexadecyl hydrogen-phosphate (DHDP) and dimysteroyl phosphatidic acid (DMPA), were spread as monolayer materials at the air/water interface, containing CsI at various concentrations. Five decades in bulk concentrations (CsI) are investigated, demonstrating that the interfacial distribution is strongly dependent on bulk concentration. We show that this is due to the strong binding constant of hydronium H3O+ to the phosphate group, leading to proton-transfer back to the phosphate group and to a reduced surface charge. Using anomalous reflectivity off and at the L3 Cs+ resonance, we provide spatial counterion (Cs+) distributions next to the negatively charged interfaces. The experimental ion distributions are in excellent agreement with a renormalized surface charge Poisson-Boltzmann theory for monovalent ions without fitting parameters or additional assumptions. Energy Scans at four fixed momentum transfers under specular reflectivity conditions near the Cs+ L3 resonance were conducted on 10-3 M CsI with DHDP monolayer materials on the surface. The energy scans exhibit a periodic dependence on photon momentum transfer. The ion distributions obtained from the analysis are in excellent agreement with those obtained from anomalous reflectivity measurements, providing further confirmation to the validity of the renormalized surface charge Poisson-Boltzmann theory for monovalent ions. Moreover, the dispersion corrections f0 and f00 for Cs+ around L3 resonance, revealing the local environment of a Cs+ ion in the solution at the interface, were extracted simultaneously with output of ion distributions.

  7. A Study of ESP in Hyperkinetic Children.

    ERIC Educational Resources Information Center

    Jampolsky, Gerald G.; Haight, Maryellen J.

    Evaluated with 10 hyperkinetic Ss (9- to 13-years-old) was whether hyperkinetic children have more extrasensory perception (ESP) than normal children and learn ESP skills more rapidly than other children. Ss were administered the Operational Assessment Tool ESP teaching instrument. Results did not support the hypothesis that hyperkinetic children…

  8. EPIDEMIOLOGICAL STUDY OF CHILDREN DIAPHYSEAL FEMORAL FRACTURES

    PubMed Central

    Hoffmann, Cassiano Ricardo; Traldi, Eduardo Franceschini; Posser, Alexandre

    2015-01-01

    Objective: To evaluate the personal, fracture, treatment and complication characteristics among patients with pediatric femoral shaft fractures attended at the pediatric orthopedic service of the Joana de Gusmão Children's Hospital. Methods: This was a retrospective cross-sectional study on a population consisting of patients with femoral shaft fractures, aged between birth and 14 years and 11 months, who were divided into four age groups. Information was obtained from medical records and was transferred to a survey questionnaire to present personal, fracture, treatment and complication variables. Results: The study population consisted of 96 patients. Their mean age was 6.8 years. The cases were predominantly among males, comprising closed fractures on the right side, in the middle third with a single line. Regarding fracture etiology, traffic accidents predominated overall in the sample. Most of the patients (74 to 77.1%) presented femoral fractures as their only injury. Conservative treatment predominated in the group younger than six years of age, and surgical treatment in the group aged 6 to 14 years and 11 months. The complications observed until bone union were: discrepancy, infection and movement limitation. The mean time taken for consolidation was 9.6 ± 2.4 weeks, varying with age. Conclusion: The features of these fractures were similar to those described in the literature and the treatment used showed good results. The Joana de Gusmão Children's Hospital has used the treatment proposed in the literature for pediatric femoral shaft fractures. PMID:27042619

  9. Resonant X-Ray Scattering Studies of Charge Order in Cuprates

    NASA Astrophysics Data System (ADS)

    Comin, Riccardo; Damascelli, Andrea

    2016-03-01

    X-ray techniques have been used for more than a century to study the atomic and electronic structure in practically any type of material. The advent of correlated electron systems, in particular complex oxides, brought about new scientific challenges and opportunities for the advancement of conventional X-ray methods. In this context, the need for new approaches capable of selectively sensing new forms of orders involving all degrees of freedom -- charge, orbital, spin, and lattice -- paved the way for the emergence and success of resonant X-ray scattering, which has become an increasingly popular and powerful tool for the study of electronic ordering phenomena in solids. We review the recent resonant X-ray scattering breakthroughs in the copper oxide high-temperature superconductors, in particular regarding the phenomenon of charge order, a broken-symmetry state occurring when valence electrons self-organize into periodic structures. After a brief historical perspective on charge order, we outline the milestones in the development of resonant X-ray scattering as well as the basic theoretical formalism underlying its unique capabilities. The rest of the review focuses on the recent contributions of resonant scattering to the advancements in our description and understanding of charge order. To conclude, we propose a series of present and upcoming challenges and discuss the future outlook for this technique.

  10. Infrared study of charge injection in organic field-effect transistors

    NASA Astrophysics Data System (ADS)

    Li, Zhiqiang

    2008-03-01

    We present a systematic infrared (IR) spectroscopic study of charge injection in organic field-effect transistors (FET). These experiments have revealed new unexpected aspects of both polymers and molecular crystals. IR spectromicroscopy was employed to image the charges in poly(3-hexylthiophene) (P3HT) FETs. The charge density profile in the conducting channel uncovers a density-dependent mobility in P3HT due to disorder effects. Our IR studies of single crystal rubrene based FETs show that charge transport in these devices at room temperature is governed by light quasiparticles in molecular orbital bands. This result is at variance with the common beliefs of polaron formation in molecular solids. The above experiments have demonstrated the unique potential of IR spectroscopy for investigating physical phenomena at the nanoscale occurring at the semiconductor-insulator interface in FET devices. This work is in collaboration with G. M. Wang, D. Moses, A. J. Heeger (UCSB), V. Podzorov, M.E. Gershenson (Rutgers), Z. Hao, M. C. Martin (ALS), N. Sai, A. D. Meyertholen, M. M. Fogler, M. Di Ventra and D. N. Basov (UCSD).

  11. Children

    ERIC Educational Resources Information Center

    Headley, Clea; Campbell, Marilyn A.

    2013-01-01

    This study examined primary school teachers' knowledge of anxiety and excessive anxiety symptoms in children. Three hundred and fifteen primary school teachers completed a questionnaire exploring their definitions of anxiety and the indications they associated with excessive anxiety in primary school children. Results showed that teachers had an…

  12. Kids' Perceptions toward Children's Ward Healing Environments: A Case Study of Taiwan University Children's Hospital

    PubMed Central

    Lin, Yi-Ling

    2016-01-01

    This paper summarizes the opinions of experts who participated in designing the environment of a children's hospital and reports the results of a questionnaire survey conducted among hospital users. The grounded theory method was adopted to analyze 292 concepts, 79 open codes, 25 axial codes, and 4 selective codes; in addition, confirmatory factor analysis and reliability analysis were performed to identify elements for designing a healing environment in a children's hospital, and 21 elements from 4 dimensions, namely, emotions, space design, interpersonal interaction, and pleasant surroundings, were determined. Subsequently, this study examined the perceptions of 401 children at National Taiwan University Children's Hospital. The results revealed that, regarding the children's responses to the four dimensions and their overall perception, younger children accepted the healing environment to a significantly higher degree than did older children. The sex effect was significant for the space design dimension, and it was not significant for the other dimensions.

  13. In Defense of Children's Lies: On Ethics and Methods of Studying Children's Communication of Deception.

    ERIC Educational Resources Information Center

    Feldman, Robert S.

    Studies of children's deceptive behavior have scientific merit and can be carried out in an ethically defensible manner. Many arguments against studies requiring children to deceive others in an experimental context are relatively easy to refute. It is true, though, that the debriefing phase of deception studies presents ethical problems,…

  14. Wandering spleen in children: multicenter retrospective study.

    PubMed

    Fiquet-Francois, Caroline; Belouadah, Mohamed; Ludot, Hugues; Defauw, Benoit; Mcheik, Jiad Noel; Bonnet, Jean Paul; Kanmegne, Charly Udozen; Weil, Dominique; Coupry, Lionel; Fremont, Benjamin; Becmeur, Francois; Lacreuse, Isabelle; Montupet, Philippe; Rahal, Eliane; Botto, Nathalie; Cheikhelard, Alaa; Sarnacki, Sabine; Petit, Thierry; Poli Merol, Marie Laurence

    2010-07-01

    Wandering spleen in children is a rare condition. The diagnosis is difficult, and any delay can cause splenic ischemia. An epidemiologic, semiological, and surgical diagnosis questionnaire on incidence of wandering spleen in children was sent to several French surgical teams. We report the results of this multicenter retrospective study. Fourteen cases (6 girls, 8 boys) were reported between 1984 and 2009; the age range varies between 1-day-old and 15 years; 86% were seen in the emergency department. Ninety-three percent had diffuse abdominal pain. For 57% of the cases, it was their first symptomatic episode of this type. No diagnosis was established based on the clinical results alone. All patients had presurgical imaging diagnosis. Open surgery was performed on 64% cases. Forty-three had splenectomy for splenic ischemia. Thirty-six percent had splenopexy, 14% had laparoscopic gastropexy, and 7% had spleen repositioning and regeneration. Complications were noted in 60% of the cases resulting in postsplenopexy splenic ischemia. Early diagnosis and surgery are the best guarantee for spleen preservation. Even if the choice of one technique, splenopexy or gastropexy, can be argued, gastropexy has the advantage of avoiding splenic manipulation and restoring proper physiologic anatomy. When there is no history of abdominal surgery, laparoscopy surgery seems the best procedure.

  15. Homoleptic copper(I) arylthiolates as a new class of p-type charge carriers: structures and charge mobility studies.

    PubMed

    Che, Chi-Ming; Li, Cheng-Hui; Chui, Stephen Sin-Yin; Roy, V A L; Low, Kam-Hung

    2008-01-01

    Polymeric homoleptic copper(I) arylthiolates [Cu(p-SC(6)H(4)-X)](infinity) (X=CH(3) (1), H (2), CH(3)O (3), tBu (4), CF(3) (5), NO(2) (6), and COOH (7)) have been prepared as insoluble crystalline solids in good yields (75-95 %). Structure determinations by powder X-ray diffraction analysis have revealed that 1-3 and 6 form polymers of infinite chain length, with the copper atoms bridged by arylthiolate ligands. Weak intra-chain pi***pi stacking interactions are present in 1-3, as evidenced by the distances (3.210 A in 1, 3.016 A in 2, 3.401 A in 3) between the mean planes of neighboring phenyl rings. In the structure of 6, the intra-chain pi***pi interactions (d=3.711 A) are insignificant and the chain polymers are associated through weak, non-covalent C-H...O hydrogen-bonding interactions (d=2.586 A). Samples of 1-7 in their polycrystalline forms proved to be thermally stable at 200-300 degrees C; their respective decomposition temperatures are around 100 degrees C higher than that of the aliphatic analogue [Cu(SCH(3))](infinity). Data from in situ variable-temperature X-ray diffractometry measurements indicated that the structures of both 1 and 7 are thermally more robust than that of [Cu(SCH(3))](infinity). TEM analysis revealed that the solid samples of 1-5 and [Cu(SCH(3))](infinity) contained homogeneously dispersed crystalline nanorods with widths of 20-250 nm, whereas smaller plate-like nanocrystals were found for 6 and 7. SAED data showed that the chain polymers of 1-3 and [Cu(SCH(3))](infinity) similarly extend along the long axes of their nanorods. The nanorods of 1-5 and [Cu(SCH(3))](infinity) have been found to exhibit p-type field-effect transistor behavior, with charge mobility (micro) values of 10(-2)-10(-5) cm(2) V(-1) s(-1). Polycrystalline solid samples of 6 and 7 each showed a low charge mobility (<10(-6) cm(2) V(-1) s(-1)). The charge mobility values of field-effect transistors made from crystalline nanorods of 1-3 and [Cu(SCH(3))](infinity

  16. Spectrophotometric study of the charge transfer complex between 2-amino-4-picoline with chloranilic acid

    NASA Astrophysics Data System (ADS)

    Alghanmi, Reem M.; Al-Attas, Amirah S.; Habeeb, Moustafa M.

    2013-02-01

    Charge transfer complex formation between 2-amino-4-picoline (2A4P) as the electron donor with chloranilic acid (CLA) as the electron acceptor has been studied spectrophotometrically in different polar solvents included acetone (AcN), ethanol (EtOH) and acetonitrile (AN). The molecular composition of the formed complex was recognized utilizing Job's, photometric and conductometric titration methods to be 1:1. The formation constants and molecular extinction coefficients were estimated using Benesi-Hildebrand equation; they recorded high values confirming high stability of the formed complex. Moreover, the results showed that the complex is more stable in acetone with lower electric permittivity compared with ethanol or acetonitrile of higher ones. The values of some spectroscopic physical parameters like oscillator strength f, transition dipole moment μ, resonance energy RN, charge transfer energy ECT, dissociation energy W, ionization potential IP and standard free energy ΔGo were determined and evaluated. The solid complex was isolated and its molecular composition was determined by elemental analysis to be 1:1. Furthermore, the solid complex was characterized using FTIR and 1H NMR measurements. They confirmed the presence of proton transfer beside charge transfer in the obtained complex. Molecular orbital calculations utilizing GAMESS computations were carried out to predict infrared spectra. They also confirmed the presence of proton transfer beside charge transfer in the formed complex.

  17. Study of the impurity composition and effective plasma charge in the GOL-3 facility

    SciTech Connect

    Sorokina, N. V. Burdakov, A. V.; Ivanov, I. A.; Polosatkin, S. V.; Postupaev, V. V.; Rovenskikh, A. F.; Shoshin, A. A.

    2015-07-15

    Heating and confinement of plasma in a multimirror magnetic configuration have been studied at the GOL-3 facility (Budker Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk). The experiments are aimed at estimating the densities and charge states of the main impurities in the GOL-3 plasma and determining their contribution to the effective plasma charge. Plasma with a density of ∼10{sup 15} cm{sup −3} was heated by a relativistic electron beam (1 MeV, 8 μs, ⩽200 kJ). At the end of electron beam injection, the plasma temperature reached 1 keV. The densities of impurities were determined using VUV and visible spectroscopy, as well as mass spectrometry of the residual vacuum. To determine the effective plasma charge, the experimental data were compared with the results of numerical simulations of the ionization balance of impurities. It is shown that the effective plasma charge calculated with allowance for the contributions from the main impurities does not exceed Z{sub eff} = 1.8, which cannot explain the experimentally observed improved confinement of low-density plasma.

  18. A feasibility study of space-charge neutralized ion induction linacs: Final report

    SciTech Connect

    Slutz, S.A.; Primm, P.; Renk, T.; Johnson, D.J.

    1997-03-01

    Applications for high current (> 1 kA) ion beams are increasing. They include hardening of material surfaces, transmutation of radioactive waste, cancer treatment, and possibly driving fusion reactions to create energy. The space-charge of ions limits the current that can be accelerated in a conventional ion linear accelerator (linac). Furthermore, the accelerating electric field must be kept low enough to avoid the generation and acceleration of counter-streaming electrons. These limitations have resulted in ion accelerator designs that employ long beam lines and would be expensive to build. Space-charge neutralization and magnetic insulation of the acceleration gaps could substantially reduce these two limitations, but at the expense of increasing the complexity of the beam physics. We present theory and experiments to determine the degree of charge-neutralization that can be achieved in various environments found in ion accelerators. Our results suggest that, for high current applications, space-charge neutralization could be used to improve on the conventional ion accelerator technology. There are two basic magnetic field geometries that can be used to insulate the accelerating gaps, a radial field or a cusp field. We will present studies related to both of these geometries. We shall also present numerical simulations of {open_quotes}multicusp{close_quotes} accelerator that would deliver potassium ions at 400 MeV with a total beam power of approximately 40 TW. Such an accelerator could be used to drive fusion.

  19. The study towards high intensity high charge state laser ion sources

    NASA Astrophysics Data System (ADS)

    Zhao, H. Y.; Jin, Q. Y.; Sha, S.; Zhang, J. J.; Li, Z. M.; Liu, W.; Sun, L. T.; Zhang, X. Z.; Zhao, H. W.

    2014-02-01

    As one of the candidate ion sources for a planned project, the High Intensity heavy-ion Accelerator Facility, a laser ion source has been being intensively studied at the Institute of Modern Physics in the past two years. The charge state distributions of ions produced by irradiating a pulsed 3 J/8 ns Nd:YAG laser on solid targets of a wide range of elements (C, Al, Ti, Ni, Ag, Ta, and Pb) were measured with an electrostatic ion analyzer spectrometer, which indicates that highly charged ions could be generated from low-to-medium mass elements with the present laser system, while the charge state distributions for high mass elements were relatively low. The shot-to-shot stability of ion pulses was monitored with a Faraday cup for carbon target. The fluctuations within ±2.5% for the peak current and total charge and ±6% for pulse duration were demonstrated with the present setup of the laser ion source, the suppression of which is still possible.

  20. Charging studies of heat packs using parabolic dish solar energy concentrator for extreme conditions

    NASA Astrophysics Data System (ADS)

    Kumar, Rohitash; Vyas, Sumita; Kumar, Ravindra; Dixit, Ambesh

    2016-05-01

    Parabolic dish solar energy concentrator with aperture diameter 1.4 m and focal length 0.32 m is designed and fabricated to charge and store solar thermal energy in phase change material (PCM) based heat packs. Overall heat loss factor, heat duty, over all thermal efficiency, and optical efficiency factor are calculated using water sensible heating and cooling tests and values are 16.11 W m-2 K-1, 546.9 W, 49.2% and 0.62 respectively. The performance characteristic curve is generated using these parameters to understand its performance at different ambient temperatures and solar insolation. The fabricated concentrator has been used to charge 16 PCM heat packs with 150 g PCM in each heat pack, which took about 35 minutes for complete charging of PCM heat packs at average ambient temperature 39 °C and solar radiation flux density 715 W m-2 K-1. The charged heat packs are subjected to discharge studies at average ambient temperature about - 7 °C and observed heat release in the temperature range of 48 to 40 °C for 50 minutes, suggesting its applications for comfort and therapeutic applications in high altitude areas.

  1. The study towards high intensity high charge state laser ion sources.

    PubMed

    Zhao, H Y; Jin, Q Y; Sha, S; Zhang, J J; Li, Z M; Liu, W; Sun, L T; Zhang, X Z; Zhao, H W

    2014-02-01

    As one of the candidate ion sources for a planned project, the High Intensity heavy-ion Accelerator Facility, a laser ion source has been being intensively studied at the Institute of Modern Physics in the past two years. The charge state distributions of ions produced by irradiating a pulsed 3 J/8 ns Nd:YAG laser on solid targets of a wide range of elements (C, Al, Ti, Ni, Ag, Ta, and Pb) were measured with an electrostatic ion analyzer spectrometer, which indicates that highly charged ions could be generated from low-to-medium mass elements with the present laser system, while the charge state distributions for high mass elements were relatively low. The shot-to-shot stability of ion pulses was monitored with a Faraday cup for carbon target. The fluctuations within ±2.5% for the peak current and total charge and ±6% for pulse duration were demonstrated with the present setup of the laser ion source, the suppression of which is still possible.

  2. Longitudinal study of spatial working memory development in young children.

    PubMed

    Tsujii, Takeo; Yamamoto, Eriko; Masuda, Sayako; Watanabe, Shigeru

    2009-05-27

    This study longitudinally compared activity in the frontal cortex during a spatial working memory task between 5-year-old and 7-year-old children using near-infrared spectroscopy. Eight children participated in this study twice, once at 5 years and once at 7 years of age. Behavioral analysis showed that older children performed the working memory task more precisely and more rapidly than younger children. Near-infrared spectroscopy analysis showed that right hemisphere dominance was observed in older children, whereas no hemispheric difference was apparent in younger children. Children with strengthened lateralization showed improved performance from 5 to 7 years. We therefore offer the first demonstration of the developmental changes in frontal cortical activation during spatial working memory tasks during the preschool period.

  3. Children's Digital Practices: Case Studies of Children Viewing and Representing with Digital Text

    ERIC Educational Resources Information Center

    Churchill, Daniel; Khoo, Kay Yong

    2012-01-01

    This paper reports on case studies of four primary school children and their digital practices in Hong Kong. The study explored how the participating children view and represent through digital text in the context of their out-of-school technology use. Understanding how these practices extended into their English language classrooms was explicated…

  4. Clinical cardiac regenerative studies in children

    PubMed Central

    Pavo, Imre J; Michel-Behnke, Ina

    2017-01-01

    Although the incidence of pediatric heart failure is low, the mortality is relatively high, with severe clinical symptoms requiring repeated hospitalization or intensive care treatment in the surviving patients. Cardiac biopsy specimens have revealed a higher number of resident human cardiac progenitor cells, with greater proliferation and differentiation capacity, in the neonatal period as compared with adults, demonstrating the regeneration potential of the young heart, with rising interest in cardiac regeneration therapy in critically ill pediatric patients. We review here the available literature data, searching the MEDLINE, Google Scholar and EMBASE database for completed, and www.clinicaltrials.gov homepage for ongoing studies involving pediatric cardiac regeneration reports. Because of difficulties conducting randomized blinded clinical trials in pediatric patients, mostly case reports or cohort studies with a limited number of individuals have been published in the field of pediatric regenerative cardiology. The majority of pediatric autologous cell transplantations into the cardiac tissue have been performed in critically ill children with severe or terminal heart failure. Congenital heart disease, myocarditis, and idiopathic hypertrophic or dilated cardiomyopathy leading to congestive heart failure are some possible areas of interest for pediatric cardiac regeneration therapy. Autologous bone marrow mononuclear cells, progenitor cells, or cardiospheres have been applied either intracoronary or percutaneously intramyocardially in severely ill children, leading to a reported clinical benefit of cell-based cardiac therapies. In conclusion, compassionate use of autologous stem cell administration has led to at least short-term improvement in heart function and clinical stability in the majority of the critically ill pediatric patients. PMID:28289528

  5. Clinical cardiac regenerative studies in children.

    PubMed

    Pavo, Imre J; Michel-Behnke, Ina

    2017-02-26

    Although the incidence of pediatric heart failure is low, the mortality is relatively high, with severe clinical symptoms requiring repeated hospitalization or intensive care treatment in the surviving patients. Cardiac biopsy specimens have revealed a higher number of resident human cardiac progenitor cells, with greater proliferation and differentiation capacity, in the neonatal period as compared with adults, demonstrating the regeneration potential of the young heart, with rising interest in cardiac regeneration therapy in critically ill pediatric patients. We review here the available literature data, searching the MEDLINE, Google Scholar and EMBASE database for completed, and www.clinicaltrials.gov homepage for ongoing studies involving pediatric cardiac regeneration reports. Because of difficulties conducting randomized blinded clinical trials in pediatric patients, mostly case reports or cohort studies with a limited number of individuals have been published in the field of pediatric regenerative cardiology. The majority of pediatric autologous cell transplantations into the cardiac tissue have been performed in critically ill children with severe or terminal heart failure. Congenital heart disease, myocarditis, and idiopathic hypertrophic or dilated cardiomyopathy leading to congestive heart failure are some possible areas of interest for pediatric cardiac regeneration therapy. Autologous bone marrow mononuclear cells, progenitor cells, or cardiospheres have been applied either intracoronary or percutaneously intramyocardially in severely ill children, leading to a reported clinical benefit of cell-based cardiac therapies. In conclusion, compassionate use of autologous stem cell administration has led to at least short-term improvement in heart function and clinical stability in the majority of the critically ill pediatric patients.

  6. Photodissociation and charge transfer dynamics of negative ions studied with femtosecond photoelectron spectroscopy

    SciTech Connect

    Zanni, Martin Thomas

    1999-12-01

    This dissertation presents studies aimed at understanding the potential energy surfaces and dynamics of isolated negative ions, and the effects of solvent on each. Although negative ions play important roles in atmospheric and solution phase chemistry, to a large extent the ground and excited state potential energy surfaces of gas phase negative ions are poorly characterized, and solvent effects even less well understood. In an effort to fill this gap, the author's coworkers and the author have developed a new technique, anion femtosecond photoelectron spectroscopy, and applied it to gas phase photodissociation and charge transfer processes. Studies are presented that (1) characterize the ground and excited states of isolated and clustered anions, (2) monitor the photodissociation dynamics of isolated and clustered anions, and (3) explore the charge-transfer-to-solvent states of atomic iodide clustered with polar and non-polar solvents.

  7. An Internet study of men sexually attracted to children: Sexual attraction patterns.

    PubMed

    Bailey, J Michael; Hsu, Kevin J; Bernhard, Paula A

    2016-10-01

    To our knowledge, this is the first large study of the attractions of child-attracted men recruited in any manner other than their being charged with legal offenses. We recruited 1,189 men from websites for adults attracted to children. Men in our sample were highly attracted to children, and they were much less attracted to adults, especially to adult men. However, men varied with respect to which combination of gender and age they found most attractive. Men in our sample were especially attracted to pubescent boys and prepubescent girls. Their self-reported attraction patterns closely tracked the age/gender gradient of sexual arousal established in prior research. Consistent with the gradient, men most attracted to prepubescent children were especially likely to have bisexual attractions to children. Pedohebephilia-attraction to sexually immature children-is best considered a collection of related if distinct sexual orientations, which vary in the particular combination of gender and sexual maturity that elicits greatest sexual attraction. Finally, our study reveals the potential power and efficiency of studying highly cooperative child-attracted men recruited via the Internet. (PsycINFO Database Record

  8. Another Day in the Life of the National Children's Study

    ERIC Educational Resources Information Center

    Balsam, Marion

    2009-01-01

    Five years ago, the editor of "Exceptional Parent" Magazine requested the author to provide an account of a day in the life of the National Children's Study, an ambitious study by the federal government that aims to find out how the environment affects child health and development. Planning and implementation of the National Children's Study has…

  9. Microscopic studies of the fate of charges in organic semiconductors: Scanning Kelvin probe measurements of charge trapping, transport, and electric fields in p- and n-type devices

    NASA Astrophysics Data System (ADS)

    Smieska, Louisa Marion

    Organic semiconductors could have wide-ranging applications in lightweight, efficient electronic circuits. However, several fundamental questions regarding organic electronic device behavior have not yet been fully addressed, including the nature of chemical charge traps, and robust models for injection and transport. Many studies focus on engineering devices through bulk transport measurements, but it is not always possible to infer the microscopic behavior leading to the observed measurements. In this thesis, we present scanning-probe microscope studies of organic semiconductor devices in an effort to connect local properties with local device behavior. First, we study the chemistry of charge trapping in pentacene transistors. Working devices are doped with known pentacene impurities and the extent of charge trap formation is mapped across the transistor channel. Trap-clearing spectroscopy is employed to measure an excitation of the pentacene charge trap species, enabling identification of the degradationrelated chemical trap in pentacene. Second, we examine transport and trapping in peryelene diimide (PDI) transistors. Local mobilities are extracted from surface potential profiles across a transistor channel, and charge injection kinetics are found to be highly sensitive to electrode cleanliness. Trap-clearing spectra generally resemble PDI absorption spectra, but one derivative yields evidence indicating variation in trap-clearing mechanisms for different surface chemistries. Trap formation rates are measured and found to be independent of surface chemistry, contradicting a proposed silanol trapping mechanism. Finally, we develop a variation of scanning Kelvin probe microscopy that enables measurement of electric fields through a position modulation. This method avoids taking a numeric derivative of potential, which can introduce high-frequency noise into the electric field signal. Preliminary data is presented, and the theoretical basis for electric field

  10. Laboratory studies of the charge neutralization of a rocket payload during electron beam emission

    NASA Technical Reports Server (NTRS)

    Bernstein, W.; Whalen, B. A.; Harris, F. R.; Mcnamara, A. G.; Konradi, A.

    1980-01-01

    The charge neutralization of an electrically-isolated rocket payload emitting an energetic electron beam has been studied in experiments in the large vacuum chamber at Johnson Space Center. The introduction of an RF-discharge-produced ambient plasma density (10,000 to 50,000 per cu cm) reduces the payload potential to 200 V for low current (1 and 10 ma) beams. The ignition of the beam-plasma discharge provides an efficient neutralization process for higher current beams.

  11. Hybrid QM/MM study of FMO complex with polarized protein-specific charge

    PubMed Central

    Jia, Xiangyu; Mei, Ye; Zhang, John Z.H.; Mo, Yan

    2015-01-01

    The Fenna-Matthews-Olson (FMO) light-harvesting complex is now one of the primary model systems for the study of excitation energy transfer (EET). However, the mechanism of the EET in this system is still controversial. In this work, molecular dynamics simulations and the electrostatic-embedding quantum-mechanics/molecular-mechanics single-point calculations have been employed to predict the energy transfer pathways utilizing the polarized protein-specific charge (PPC), which provides a more realistic description of Coulomb interaction potential in the protein than conventional mean-field charge scheme. The recently discovered eighth pigment has also been included in this study. Comparing with the conventional mean-field charges, more stable structures of FMO complex were found under PPC scheme during molecular dynamic simulation. Based on the electronic structure calculations, an exciton model was constructed to consider the couplings during excitation. The results show that pigments 3 and 4 dominate the lowest exciton levels whereas the highest exciton level are mainly constituted of pigments 1 and 6. This observation agrees well with the assumption based on the spatial distribution of the pigments. Moreover, the obtained spectral density in this study gives a reliable description of the diverse local environment embedding each pigment. PMID:26611739

  12. Hybrid QM/MM study of FMO complex with polarized protein-specific charge.

    PubMed

    Jia, Xiangyu; Mei, Ye; Zhang, John Z H; Mo, Yan

    2015-11-27

    The Fenna-Matthews-Olson (FMO) light-harvesting complex is now one of the primary model systems for the study of excitation energy transfer (EET). However, the mechanism of the EET in this system is still controversial. In this work, molecular dynamics simulations and the electrostatic-embedding quantum-mechanics/molecular-mechanics single-point calculations have been employed to predict the energy transfer pathways utilizing the polarized protein-specific charge (PPC), which provides a more realistic description of Coulomb interaction potential in the protein than conventional mean-field charge scheme. The recently discovered eighth pigment has also been included in this study. Comparing with the conventional mean-field charges, more stable structures of FMO complex were found under PPC scheme during molecular dynamic simulation. Based on the electronic structure calculations, an exciton model was constructed to consider the couplings during excitation. The results show that pigments 3 and 4 dominate the lowest exciton levels whereas the highest exciton level are mainly constituted of pigments 1 and 6. This observation agrees well with the assumption based on the spatial distribution of the pigments. Moreover, the obtained spectral density in this study gives a reliable description of the diverse local environment embedding each pigment.

  13. STUDIES OF PRESCHOOL CHILDREN'S EXPOSURES TO PESTICIDES

    EPA Science Inventory

    Young children, especially those of the preschool ages, are hypothesized to have greater exposures than do older children or adults to persistent organic pesticides and other persistent organic pollutants, including some compounds that may have endocrine-disrupting effects or d...

  14. Assessing Children's Values: An Exploratory Study

    ERIC Educational Resources Information Center

    Doring, Anna K.

    2010-01-01

    Currently, much attention is devoted to children's values and their development in an educational context. Recent research revealed that children hold a solid concept of their values and may provide accurate and unique information by themselves. Schwartz's (1994) theory established a comprehensive framework of universal human values, and…

  15. Numerical Study of Three Dimensional Effects in Longitudinal Space-Charge Impedance

    SciTech Connect

    Halavanau, A.; Piot, P.

    2015-06-01

    Longitudinal space-charge (LSC) effects are generally considered as detrimental in free-electron lasers as they can seed instabilities. Such “microbunching instabilities” were recently shown to be potentially useful to support the generation of broadband coherent radiation pulses [1, 2]. Therefore there has been an increasing interest in devising accelerator beamlines capable of sustaining this LSC instability as a mechanism to produce a coherent light source. To date most of these studies have been carried out with a one-dimensional impedance model for the LSC. In this paper we use a N-body “Barnes-Hut” algorithm [3] to simulate the 3D space charge force in the beam combined with elegant [4] and explore the limitation of the 1D model often used

  16. Numerical studies of the Weibel Instability in Intense Charged Particle Beams with Large Energy Anisotropy

    NASA Astrophysics Data System (ADS)

    Lee, Wei-Li; Startsev, Edward A.; Davidson, Ronald C.

    2004-11-01

    In intense charged particle beams with large temperature anisotropy free energy is available to drive a transverse electromagnetic Weibel-type instability. The finite transverse geometry of the confined beam makes a detailed theoretical investigation difficult. In this paper the newly developed bEASt (beam eigenmode and spectra) code which solves the linearized Vlasov-Maxwell equations is used to investigate the detailed properties of the Weibel instability for a long charge bunch propagating through a cylindrical pipe of radius r_w. The stability analysis is carried out for azimuthally symmetric perturbations about a two-temperature thermal equilibrium distribution in the smooth-focusing approximation. To study the nonlinear stage of the instability, the Darwin model is being developed and incorporated into the Beam Equilibrium Stability and Transport(BEST) code.

  17. Fundamental Studies of Charge Migration and Delocalization Relevant to Solar Energy Conversion

    SciTech Connect

    Michael J. Therien

    2012-06-01

    This program aimed to understand the molecular-level principles by which complex chemical systems carry out photochemical charge separation, transport, and storage, and how these insights could impact the design of practical solar energy conversion and storage devices. Towards these goals, this program focused on: (1) carrying out fundamental mechanistic and transient dynamical studies of proton-coupled electron-transfer (PCET) reactions; (2) characterizing and interrogating via electron paramagnetic resonance (EPR) spectroscopic methods novel conjugated materials that feature large charge delocalization lengths; and (3) exploring excitation delocalization and migration, as well as polaron transport properties of meso-scale assemblies that are capable of segregating light-harvesting antennae, nanoscale wire-like conduction elements, and distinct oxidizing and reducing environments.

  18. Theoretical study of charge transfer dynamics in collisions of C6+ carbon ions with pyrimidine nucleobases

    NASA Astrophysics Data System (ADS)

    Bacchus-Montabonel, M. C.

    2012-07-01

    A theoretical approach of the charge transfer dynamics induced by collision of C6+ ions with biological targets has been performed in a wide collision energy range by means of ab-initio quantum chemistry molecular methods. The process has been investigated for the target series thymine, uracil and 5-halouracil corresponding to similar molecules with different substituent on carbon C5. Such a study may be related to hadrontherapy treatments by C6+carbon ions and may provide, in particular, information on the radio-sensitivity of the different bases with regard to ion-induced radiation damage. The results have been compared to a previous analysis concerning the collision of C4+ carbon ions with the same biomolecular targets and significant charge effects have been pointed out.

  19. Charge-exchange erosion studies of accelerator grids in ion thrusters

    NASA Technical Reports Server (NTRS)

    Peng, Xiaohang; Ruyten, Wilhelmus M.; Keefer, Dennis

    1993-01-01

    A particle simulation model is developed to study the charge-exchange grid erosion in ion thrusters for both ground-based and space-based operations. Because the neutral gas downstream from the accelerator grid is different for space and ground operation conditions, the charge-exchange erosion processes are also different. Based on an assumption of now electric potential hill downstream from the ion thruster, the calculations show that the accelerator grid erosion rate for space-based operating conditions should be significantly less than experimentally observed erosion rates from the ground-based tests conducted at NASA Lewis Research Center (LeRC) and NASA Jet Propulsion Laboratory (JPL). To resolve this erosion issue completely, we believe that it is necessary to accurately measure the entire electric potential field downstream from the thruster.

  20. Workplace Charging. Charging Up University Campuses

    SciTech Connect

    Giles, Carrie; Ryder, Carrie; Lommele, Stephen

    2016-03-01

    This case study features the experiences of university partners in the U.S. Department of Energy's (DOE) Workplace Charging Challenge with the installation and management of plug-in electric vehicle (PEV) charging stations.

  1. Applications of scanning tunneling microscopy to the study of charge density waves

    NASA Astrophysics Data System (ADS)

    Coleman, R. V.; Drake, B.; Giambattista, B.; Johnson, A.; Hansma, P. K.; McNairy, W. W.; Slough, G.

    1988-08-01

    Scanning tunneling microscopy (STM) studies of the surfaces of transition metal di- and tri-chalcogenides have been used to detect a variety of charge-density-wave (CDW) contributions to the surface charge modulation at 77 and 4.2K. In the 1T phases of TaSe2 and TaS2 strong charge maxima are observed which correspond to the √13 a0 × √13 a0 superlattice generated by the CDWs formed as standing waves from the conduction electrons. The charge-density contours located between the charge maxima show major contributions from the detailed arrangement of surface Se or S atom. The z-deflection observed from the total surface charge-density modulation in the 1T phases is extremely large in the range 1.0 to 2.5Å. The STM scans show the same general structure for the 1T phases at both 77 and 4.2K, but variations in the z-deflection suggest some temperature dependence of the CDW amplitude. The observations are consistent with band structure considerations and the large electron transfer associated with the CDWs. In 2H-TaSe2 at 77K and in 2H-NbSe2 at 4.2K the CDWs are much weaker than in the 1T phases and contribute only small deflections to the STM scans which are mainly dominated by the atomic modulation of the surface charge-density. The linear chain compound NbSe3 has two CDW transitions, one at 144K and one at 59K. The STM scans at 77K with only one CDW present and only 20% of the Fermi surface gapped show no detectable contribution to the surface charge modulation at the CDW wavelength. The z-deflection shows a large surface modulation and resolves the three chains per surface unit cell, but the STM pattern can be matched to the expected height and charge variations of the surface Se atoms. At 4.2K the two CDWs present in NbSe3 gap approximately 80% of the Fermi surface and a modulation at the CDW wavelength of ~ 4b0 along the chain axis can be analyzed in terms of the band structure and CDW formation. Initial STM scans have also been performed at 77K on the linear

  2. Charged colloid-polymer mixtures: a study on electrostatic depletion attraction.

    PubMed

    Peláez-Fernández, M; Moncho-Jordá, A; Callejas-Fernández, J

    2011-02-07

    In this work, light scattering methods have been used to study the effect of adding charged polymer chains on the structural and dynamic properties of a charged colloidal system. The experimental measurements of the static structure factor S(cc)(q) show that as the polymer concentration increases, the main peak moves to higher q-values, which is interpreted in terms of the electrostatically enhanced depletion attraction induced by the polymer. Moreover, we found that the shift of the peak depends on the interplay between two relevant length scales, the polymer radius of gyration, R(g), and the Debye length, κ(-1). To reach these conclusions, the polymer reference interaction site model has been employed to explain the experimental results and to study how the effective depletion attraction depends on the polymer concentration, R(g) and κ(-1). Additionally, the measurements of the dynamic structure factor f(q, τ) indicate that the colloidal diffusion increases with the polymer concentration. Both static and dynamic analysis point out that the repulsion between colloids becomes weaker as the charged polymer is added.

  3. Sleep in children with asthma: results of the PIAMA study.

    PubMed

    van Maanen, Annette; Wijga, Alet H; Gehring, Ulrike; Postma, Dirkje S; Smit, Henriëtte A; Oort, Frans J; Rodenburg, Roos; Meijer, Anne Marie

    2013-04-01

    Children with asthma are thought to have impaired sleep quality and quantity. In this study, we investigated which of the many sleep aspects are associated with asthma. Our sample consisted of 2529 children (aged 11 years) who participated in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) birth cohort study. Parents reported about asthma symptoms (wheezing, dyspnoea, prescription of inhaled corticosteroids and asthma diagnosis) and children reported about different aspects of sleep (bedtime, rise time, sleep quality and daytime sleepiness/tiredness). Results were analysed with (logistic) regression analysis. Children with frequent asthma symptoms significantly more often reported that they felt sleepy or tired during the day (34.4% experienced daytime sleepiness/tiredness at least once a week) than children without asthma symptoms (22.2%) and children with infrequent asthma symptoms (21.9%). This association was not confounded by sex, age of the child, parental educational level or smoking inside the house; the effect was also not modified by sex. There were no associations between asthma and bedtime, time spent in bed or sleep quality. Children with frequent asthma symptoms experienced daytime sleepiness/tiredness more often than children with infrequent or no asthma symptoms. Otherwise, children with asthma did not differ much from children without asthma with regard to sleep.

  4. Study of multi-electron ionization and charge exchange in HIBF

    NASA Astrophysics Data System (ADS)

    Wu, Linchun

    Beam ion stripping on background gases or plasma in a Heavy Ion Beam Fusion (HIBF) chamber increases the charge state of the beam and the diameter of the focus, complicating the final focusing on the focusing target. To model beam transport in the chamber, it is necessary to know the beam charge-state evolution, including both ionization and charge exchange dynamics. The main objective of this research is to explore theoretical approaches including scaling law. Improved models are developed to calculate multi-electron loss, especially ion stripping and charge exchange cross sections, for both near-term experiments and future power plant scale HIBF research. First, a new space-charge neutralization approach that uses electron injection is proposed for the ion beam transport in HIBF chamber. An analytical study was performed to illustrate the plasma dynamics and final neutralization effects with this technique. The results examine the effect of different injected electron profiles. Next, to improve the accuracy of such simulations, methods to improve cross sections of ionization and charge exchange are studied. Both classical and quantum mechanical approaches are examined. Attention is focused on the interaction by low-charge-state heavy ions. Multi-electron processes for dressed ions, including screening and anti-screening effects, internuclear forces, are given special attention, This analysis is complex and requires a combining several different theoretical approaches. Finally, a Classic Trajectory Monte Carlo (CTMC) model based on an improvement of Olson's n-body CTMC method is presented. This model solves the n-body ion-atom ionization problem in a regime of intent to HIBF. In the paper, a new and complete computational module for these interactions has been developed. The cross section data for Xe, Cs, and Bi ions colliding with various background gases (Xe, N2, Ar and Flibe) is presented. After the calculation of the cross section data, the predicted energy

  5. Toddler Techies: A Study of Young Children's Interaction with Computers

    ERIC Educational Resources Information Center

    Ellis, Kirsten; Blashki, Kathy

    2004-01-01

    This article describes an ethnographic study of children's behavioural interaction with multimedia within a familiar context. The rationale for such a study was to provide data and evaluation of the capabilities of young children in an expressly modified multimedia environment and to determine the usefulness of employing technology as an adjunct…

  6. Morphological Awareness and Chinese Children's Literacy Development: An Intervention Study

    ERIC Educational Resources Information Center

    Wu, Xiaoying; Anderson, Richard C.; Li, Wenling; Wu, Xinchun; Li, Hong; Zhang, Jie; Zheng, Qiu; Zhu, Jin; Shu, Hua; Jiang, Wei; Chen, Xi; Wang, Qiuying; Yin, Li; He, Yeqin; Packard, Jerome; Gaffney, Janet S.

    2009-01-01

    The purpose of this study was to investigate the relationship between morphological awareness and Chinese children's literacy development. Of the 169 children from elementary schools in Beijing, China, who participated in the study, about half received enhanced instruction on the morphology of characters and words in the first and second grade. At…

  7. Numerical study on the effect of charge separation at low cloud temperature and effective water content on thunderstorm electrification

    NASA Astrophysics Data System (ADS)

    Tsenova, Boryana Dimitrova; Barakova, Denitsa; Mitzeva, Rumjana

    2017-02-01

    In the present study, a numerical model is used to evaluate the effects of low effective water content and low cloud temperature on graupel charging, charge structure and lightning activity in regions of thunderstorms. Two idealized cloud cases were simulated with MesoNH using different configurations of the main known parameterizations for noninductive charging involving ice crystal/graupel rebounding collisions. Simulations in regions with very low effective cloud water content were performed with the parameterization proposed in Mitzeva et al. (2006) based on the "Relative Growth Rate" hypothesis, while for simulations in regions with low cloud temperature, charge values from Avila et al. (2011) were used. Results showed that the inclusion of the charge separation at very low effective water content influences more the simulated cloud charge structure than does the inclusion of the charge separated at low temperatures. Also, the effect of the charge separated at very low effective water content is more significant when the original parameterization for non-inductive charging is based on the effective water content rather than on the rime accretion rate.

  8. Charge ordering in Nd2/3Ca1/3MnO3: ESR and magnetometry study

    NASA Astrophysics Data System (ADS)

    Polishchuk, D. M.; Tovstolytkin, A. I.; Fertman, E. L.; Desnenko, V. A.; Kravchyna, O.; Khalyavin, D. D.; Salak, A. N.; Anders, A. G.; Feher, A.

    2016-07-01

    The evolution of magnetic and electric properties of the narrow-band manganite Nd2/3Ca1/3MnO3 was studied by the electron-spin resonance (ESR), static magnetic field (dc) and resistivity techniques in the temperature range of 100-380 K. It was found that below the charge ordering temperature, TCO≈212 K, the compound is a mixture of the charge ordered and charge disordered phases in varying proportions depending on the temperature. The exchange phase process, when the amount of the charge ordered phase increases under cooling, while the amount of the charge disordered phase decreases is the most intense between ∼220 K and 180 K. At low temperatures, T<160 K, the charge ordered to the charge disordered phase ratio is about 4:1, which is in excellent agreement with previous neutron diffraction data. Both a sharp decrease of the magnetic susceptibility and a huge resistivity increase are evident of the weakening of ferromagnetic correlations and suppression of the double exchange interaction across the charge ordering due to the localization of the charge carriers.

  9. RECRUITMENT STRATEGIES FOR AN EXPOSURE MEASUREMENT STUDY OF PRESCHOOL CHILDREN

    EPA Science Inventory

    Recruiting study participants is always a challenge for researchers. It poses an even bigger challenge for researchers to recruit participants for a study involving intrusive, burdensome data collection activities. A study of preschool children's exposure to persistent organic ...

  10. An epidemiologic study of deciduous molar relations in preschool children.

    PubMed

    Infante, P F

    1975-01-01

    This study indicated that distoclusion decreased significantly with age and was more prevalent in siblings of children with Class II molar relation as compared with the prevalence for the total population. Children of middle socioeconomic status (SES) and girls with Class I molar relation had prevalences of posterior crossbite significantly greater than lower SES children and boys, respectively. Finger habits were highly associated with posterior crossbite (P less than 0.001).

  11. A study of charged particles/radiation damage to VLSI device materials

    NASA Technical Reports Server (NTRS)

    Okyere, John G.

    1987-01-01

    Future spacecraft systems such as the manned space station will be subjected to low-dose long term radiation particles. Most electronic systems are affected by such particles. There is therefore a great need to understand device physics and failure mechanisms affected by radiation and to design circuits that would be less susceptible to radiation. Using 2 MeV electron radiation and bias temperature aging, it was found that MOS capacitors that were prepositively biased have lower flatband voltage shift and lesser increase in density of surface state charge than those that were not prepositively biased. In addition, it was shown that there is continued recovery of flatband voltage and density of state charge in irradiated capacitors during both room temperature anneal and 137 degree anneal. When nMOS transistors were subjected to 1 MeV proton radiation, charge pumping and current versus voltage measurements indicated that transconductance degradation, threshold voltage shifts and changes in interface states density may be the primary cause of nMOS transistor failure after radiation. Simulation studies using SPICE were performed on CMOS SRAM cells of various transistor sizes. It is shown that transistor sizing affects the noise margins of CMOS SRAM cells, and that as the beta ratio of the transistors of the CMOS SRAM cell decreases, the effective noise margin of the SRAM cell increases. Some suggestions were made in connection with the design of CMOS SRAMS that are hardened against single event upsets.

  12. Nuclear Motion Driven Ultrafast Photodissociative Charge Transfer of the PENNA Cation: An Experimental and Computational Study.

    PubMed

    Sun, Shoutian; Mignolet, Benoit; Fan, Lin; Li, Wen; Levine, Raphael D; Remacle, Francoise

    2017-02-23

    Ultrafast nuclear driven charge transfer prior to dissociation is an important process in modular systems as was demonstrated experimentally in the bifunctional molecule 2-phenylethyl-N,N-dimethylamine (PENNA) in work by Lehr et al. ( J. Phys. Chem. A 2005 , 109 , 8074 ). The ultrafast dynamics of PENNA photoexcited to the three lowest electronic states of the cation (D0, D1, and D2) was studied using quantum chemistry and surface hoping. We show that a conical intersection, localized in the Franck-Condon region, between the D0 and the D1 states, leads to an ultrafast charge transfer, computed here to be on a time scale of 65 fs, between the phenyl and the amine charged subunits. On the D0 ground state, the dissociation proceeds on the 60 ps time scale through a 19 kcal/mol late barrier. The computed kinetic energy release is in good agreement with a new experimental measurement of PENNA ionization by an 800 nm 30 fs intense laser pulse.

  13. Studies on space charge neutralization and emittance measurement of beam from microwave ion source

    SciTech Connect

    Misra, Anuraag; Goswami, A.; Sing Babu, P.; Srivastava, S.; Pandit, V. S. E-mail: vspandit12@gmail.com

    2015-11-15

    A 2.45 GHz microwave ion source together with a beam transport system has been developed at VECC to study the problems related with the injection of high current beam into a compact cyclotron. This paper presents the results of beam profile measurement of high current proton beam at different degrees of space charge neutralisation with the introduction of neon gas in the beam line using a fine leak valve. The beam profiles have been measured at different pressures in the beam line by capturing the residual gas fluorescence using a CCD camera. It has been found that with space charge compensation at the present current level (∼5 mA at 75 keV), it is possible to reduce the beam spot size by ∼34%. We have measured the variation of beam profile as a function of the current in the solenoid magnet under the neutralised condition and used these data to estimate the rms emittance of the beam. Simulations performed using equivalent Kapchinsky-Vladimirsky beam envelope equations with space charge neutralization factor are also presented to interpret the experimental results.

  14. Overloading study of basic compounds with a positively charged C18 column in liquid chromatography.

    PubMed

    Wang, Chaoran; Guo, Zhimou; Long, Zhen; Zhang, Xiuli; Liang, Xinmiao

    2013-03-15

    While tailing and overloading of basic compounds remain problematic on most RP columns, a new kind of positively charged RP column named XCharge C18 was found to be superior good for the separation of alkaloids in our practical use. In this work, the surface charge property of the XCharge C18 column was evaluated by the retention of NO(3)(-) under different pH values and buffer concentrations. A considerable and pH-dependent positive charge was confirmed on the column. Then overloading behaviors of bases were systematically studied using amitriptyline as a basic probe. Good peak shapes (Tf<1.5) and extra high loadability with a C(0.5) of about 30,000 mg/L were observed on the column, with commonly used 0.1% formic acid as mobile phase additive. However, increasing the ionic strength of buffer with phosphates led to tailing peaks at high sample amount and sharp decline in loadability (C(0.5) of 2000-3000 mg/L), although it brought higher column efficiency at low sample amount. Higher pH also induced worse performance and lower loadability. The overall results demonstrated the importance of an appropriate level of ionic repulsion for the XCharge C18 column to achieve the good performance for bases, which could be explained by the multiple-site adsorption theory as ionic repulsion would shield the solute from occupying high-energy sites deeper in C18 layer.

  15. Density functional study of the interaction of carbon monoxide with small neutral and charged silver clusters.

    PubMed

    Zhou, Jia; Li, Zhen-Hua; Wang, Wen-Ning; Fan, Kang-Nian

    2006-06-08

    CO adsorption on small neutral, anionic, and cationic silver clusters Ag(n) (n = 1-7) has been studied with use of the PW91PW91 density functional theory (DFT) method. The adsorption of CO on-top site, among various possible sites, is energetically preferred irrespective of the charge state of the silver cluster. The cationic silver clusters generally have a greater tendency to adsorb CO than the anionic and neutral silver ones, except for n = 3 and 4, and the binding energies reach a local minimum at n = 5. The binding energies on the neutral clusters, instead, reach a local maximum at n = 3, which is about 0.87 eV, probably large enough to be captured in the experiments. Binding of CO to the silver clusters is generally weaker than that to the copper and gold counterparts at the same size and charge state. This is due to the weaker orbital interaction between silver and CO, which is caused by the larger atomic radius of the silver atom. In contrast, Au atoms with a larger nuclear charge but a similar atomic radius to silver owing to the lanthanide contraction are able to have a stronger interaction with CO.

  16. Thermal Charging Study of Compressed Expanded Natural Graphite/Phase Change Material Composites

    SciTech Connect

    Mallow, Anne M; Abdelaziz, Omar; Graham, Samuel

    2016-01-01

    The thermal charging performance of phase change materials, specifically paraffin wax, combined with compressed expanded natural graphite foam is studied under constant heat flux and constant temperature conditions. By varying the heat flux between 0.39 W/cm2 and 1.55 W/cm2 or maintaining a boundary temperature of 60 C for four graphite foam bulk densities, the impact on the rate of thermal energy storage is discussed. Thermal charging experiments indicate that thermal conductivity of the composite is an insufficient metric to compare the influence of graphite foam on the rate of thermal energy storage of the PCM composite. By dividing the latent heat of the composite by the time to melt for various boundary conditions and graphite foam bulk densities, it is determined that bulk density selection is dependent on the applied boundary condition. A greater bulk density is advantageous for samples exposed to a constant temperature near the melting temperature as compared to constant heat flux conditions where a lower bulk density is adequate. Furthermore, the anisotropic nature of graphite foam bulk densities greater than 50 kg/m3 is shown to have an insignificant impact on the rate of thermal charging. These experimental results are used to validate a computational model for future use in the design of thermal batteries for waste heat recovery.

  17. Redox probing study of the potential dependence of charge transport through Li2O2

    DOE PAGES

    Knudsen, Kristian B.; Luntz, Alan C.; Jensen, Søren H.; ...

    2015-11-20

    In the field of energy storage devices the pursuit for cheap, high energy density, reliable secondary batteries is at the top of the agenda. The Li–O2 battery is one of the possible technologies that, in theory, should be able to close the gap, which exists between the present state-of-the-art Li-ion technologies and the demand placed on batteries by technologies such as electrical vehicles. Here we present a redox probing study of the charge transfer across the main deposition product lithium peroxide, Li2O2, in the Li–O2 battery using outer-sphere redox shuttles. The change in heterogeneous electron transfer exchange rate as amore » function of the potential and the Li2O2 layer thickness (~depth-of-discharge) was determined using electrochemical impedance spectroscopy. In addition, the attenuation of the electron transfer exchange rate with film thickness is dependent on the probing potential, providing evidence that hole transport is the dominant process for charge transfer through Li2O2 and showing that the origin of the sudden death observed upon discharge is due to charge transport limitations.« less

  18. Study of Frustrative Nonreward in Children

    ERIC Educational Resources Information Center

    Kroes, William H.

    1973-01-01

    It was hypothesized that an enhancement of goal objects would occur for children who were frustrated from receiving these goal objects. Three dependent measures were used to measure the frustration effects: size estimation, verbal evaluation, and selective attention. (Author)

  19. AN OVERVIEW OF THE NATIONAL CHILDREN'S STUDY

    EPA Science Inventory

    There is substantial public health concern that aspects of the environment adversely impact child health and development. Children may be more vulnerable to environmental threats but little comprehensive research exists to identify which factors are harmful, harmless or helpful....

  20. Study on experimental motion sickness in children.

    PubMed

    Takahashi, M; Toriyabe, I; Takei, Y; Kanzaki, J

    1994-05-01

    To clarify the characteristics of motion sickness in children we investigated autonomic nervous symptoms and instability evoked by walking while wearing horizontally reversing goggles in 90 children aged 4 to 15 years. Kindergarten children had hardly any autonomic nervous symptoms except headache; however, they often fell, could not stand up or move, and exhibited a to-and-fro deviation gait. Although the frequency and severity of sickness gradually increased during growth, the severity of gait disorder became milder as age increased. On the basis of these findings it seems likely that functions which perceive disorder of spatial orientation and action are immature in young children, and once spatial orientation is impaired, instability becomes very severe, since inadequate control is not stopped by an alarm function against disorientation.

  1. An Internet study of men sexually attracted to children: Correlates of sexual offending against children.

    PubMed

    Bailey, J Michael; Bernhard, Paula A; Hsu, Kevin J

    2016-10-01

    We conducted an Internet survey of 1,102 men sexually attracted to children concerning their history of adjudicated offenses related to child pornography and sexual contact with children. Most of the men reported no offenses, but their rate of offenses was much higher than that expected for adult-attracted men. Correlates of offending are consistent with a strong role of the cumulative effects of temptation, especially age. Older men, men who had repeatedly worked in jobs with children, men who had repeatedly fallen in love with children, and men who had often struggled not to offend were especially likely to have offended. Attraction to male children, relative attraction to children versus adults, and childhood sexual abuse experiences were also strong predictors of offending. In contrast, permissive attitudes regarding child-adult sex and frequent indulgence in sexual fantasies about children were not significantly related to offending. Our findings represent the first large study of offending among men sexually attracted to children who were not recruited via contact with the legal system. Because of methodological limitations, our findings cannot be definitive. Reassuringly, however, results are generally consistent with those from the most pertinent existing studies, of recidivism among convicted sex offenders. (PsycINFO Database Record

  2. A qualitative study exploring genetic counsellors' experiences of counselling children.

    PubMed

    Ulph, Fiona; Leong, James; Glazebrook, Cris; Townsend, Ellen

    2010-10-01

    The identification of healthy carriers by newborn screening programmes raises questions about how and when the carrier results will be conveyed to child. There is currently a lack of information concerning how best to convey carrier information to children. This is a serious gap in the literature and practice. This study examined genetic counsellors' experiences of counselling children to explore how to support and inform children about their carrier result. Practising members of the United Kingdom (UK) Association of Genetic Nurses and Counsellors took part in semi-structured telephone interviews. Respondents described the communication process and identified barriers and facilitators of communication. Age, illness experience and maturity were variously discussed as facilitators; all of which are integral to psychological theories of children's understanding of illness. Adaptive family communication, school tuition and educational materials were also seen as influencing counselling efficacy. Relevant materials that children could keep were also seen as important to enhance children's autonomy. Yet, such resources were rare, constituting a barrier to communication. Counsellors reported communication was further impeded by maladaptive family communication and resistance from children to engaging in counselling. By exploring the facilitators and barriers inherent in communicating genetic information to children, guidance can be offered to counsellors, researchers and parents. This study indicates that some factors (eg illness experiences) previously identified by psychological theories may act in complex ways within this setting. Importantly, the factors identified as being most influential when communicating with children about genetics are amenable to change through interventions, support and training.

  3. Analysis of variation in charges and prices paid for vaginal and caesarean section births: a cross-sectional study

    PubMed Central

    Hsia, Renee Y; Akosa Antwi, Yaa; Weber, Ellerie

    2014-01-01

    Objective To examine the between-hospital variation of charges and discounted prices for uncomplicated vaginal and caesarean section deliveries, and to determine the institutional and market-level characteristics that influence adjusted charges. Design, setting and participants Using data from the California Office of Statewide Health Planning and Development (OSHPD), we conducted a cross-sectional study of all privately insured patients admitted to California hospitals in 2011 for uncomplicated vaginal delivery (diagnosis-related group (DRG) 775) or uncomplicated caesarean section (DRG 766). Outcome measures Hospital charges and discounted prices adjusted for each patient's clinical and demographic characteristics. Results We analysed 76 766 vaginal deliveries and 32 660 caesarean sections in California in 2011. After adjusting for patient demographic and clinical characteristics, we found that the average California woman could be charged as little as US$3296 or as much as US$37 227 for a vaginal delivery, and US$8312–US$70 908 for a caesarean section depending on which hospital she was admitted to. The discounted prices were, on an average, 37% of the charges. We found that hospitals in markets with middling competition had significantly lower adjusted charges for vaginal deliveries, while hospitals with higher wage indices and casemixes, as well as for-profit hospitals, had higher adjusted charges. Hospitals in markets with higher uninsurance rates charged significantly less for caesarean sections, while for-profit hospitals and hospitals with higher wage indices charged more. However, the institutional and market-level factors included in our models explained only 35–36% of the between-hospital variation in charges. Conclusions These results indicate that charges and discounted prices for two common, relatively homogeneous diagnosis groups—uncomplicated vaginal delivery and caesarean section—vary widely between hospitals and are not well

  4. Particle size effects in particle-particle triboelectric charging studied with an integrated fluidized bed and electrostatic separator system

    NASA Astrophysics Data System (ADS)

    Bilici, Mihai A.; Toth, Joseph R.; Sankaran, R. Mohan; Lacks, Daniel J.

    2014-10-01

    Fundamental studies of triboelectric charging of granular materials via particle-particle contact are challenging to control and interpret because of foreign material surfaces that are difficult to avoid during contacting and measurement. The measurement of particle charge itself can also induce charging, altering results. Here, we introduce a completely integrated fluidized bed and electrostatic separator system that charges particles solely by interparticle interactions and characterizes their charge on line. Particles are contacted in a free-surface fluidized bed (no reactor walls) with a well-controlled fountain-like flow to regulate particle-particle contact. The charged particles in the fountain are transferred by a pulsed jet of air to the top of a vertically-oriented electrostatic separator consisting of two electrodes at oppositely biased high voltage. The free-falling particles migrate towards the electrodes of opposite charge and are collected by an array of cups where their charge and size can be determined. We carried out experiments on a bidisperse size mixture of soda lime glass particles with systematically varying ratios of concentration. Results show that larger particles fall close to the negative electrode and smaller particles fall close to the positive electrode, consistent with theory and prior experiments that larger particles charge positively and smaller particles charge negatively. The segregation of particles by charge for one of the size components is strongest when its collisions are mostly with particles of the other size component; thus, small particles segregate most strongly to the negative sample when their concentration in the mixture is small (and analogous results occur for the large particles). Furthermore, we find additional size segregation due to granular flow, whereby the fountain becomes enriched in larger particles as the smaller particles are preferentially expelled from the fountain.

  5. Particle size effects in particle-particle triboelectric charging studied with an integrated fluidized bed and electrostatic separator system

    SciTech Connect

    Bilici, Mihai A.; Toth, Joseph R.; Sankaran, R. Mohan; Lacks, Daniel J.

    2014-10-15

    Fundamental studies of triboelectric charging of granular materials via particle-particle contact are challenging to control and interpret because of foreign material surfaces that are difficult to avoid during contacting and measurement. The measurement of particle charge itself can also induce charging, altering results. Here, we introduce a completely integrated fluidized bed and electrostatic separator system that charges particles solely by interparticle interactions and characterizes their charge on line. Particles are contacted in a free-surface fluidized bed (no reactor walls) with a well-controlled fountain-like flow to regulate particle-particle contact. The charged particles in the fountain are transferred by a pulsed jet of air to the top of a vertically-oriented electrostatic separator consisting of two electrodes at oppositely biased high voltage. The free-falling particles migrate towards the electrodes of opposite charge and are collected by an array of cups where their charge and size can be determined. We carried out experiments on a bidisperse size mixture of soda lime glass particles with systematically varying ratios of concentration. Results show that larger particles fall close to the negative electrode and smaller particles fall close to the positive electrode, consistent with theory and prior experiments that larger particles charge positively and smaller particles charge negatively. The segregation of particles by charge for one of the size components is strongest when its collisions are mostly with particles of the other size component; thus, small particles segregate most strongly to the negative sample when their concentration in the mixture is small (and analogous results occur for the large particles). Furthermore, we find additional size segregation due to granular flow, whereby the fountain becomes enriched in larger particles as the smaller particles are preferentially expelled from the fountain.

  6. A Comparative Study of the Spontaneous Social Interactions of Children with High-Functioning Autism and Children with Asperger's Disorder

    ERIC Educational Resources Information Center

    Macintosh, Kathleen; Dissanayake, Cheryl

    2006-01-01

    A comparative observational study was undertaken of the spontaneous social interactions of children with high-functioning autism and Asperger's disorder. The sample comprised 20 children with high-functioning autism, 19 children with Asperger's disorder and 17 typically developing children matched on chronological age and overall mental age. A…

  7. Children's Schooling and Parents' Investment in Children: Evidence from the Head Start Impact Study. NBER Working Paper No. 17704

    ERIC Educational Resources Information Center

    Gelber, Alexander M.; Isen, Adam

    2011-01-01

    Parents may have important effects on their children, but little work in economics explores whether children's schooling opportunities crowd out or encourage parents' investment in children. We analyze data from the Head Start Impact Study, which granted randomly-chosen preschool-aged children the opportunity to attend Head Start. We find that…

  8. Mathematics Anxiety in Young Children: An Exploratory Study

    ERIC Educational Resources Information Center

    Harari, Rachel R.; Vukovic, Rose K.; Bailey, Sean P.

    2013-01-01

    This study explored the nature of mathematics anxiety in a sample of 106 ethnically and linguistically diverse first-grade students. Although much is known about mathematics anxiety in older children and adults, little is known about when mathematics anxiety first emerges or its characteristics in young children. Results from exploratory factor…

  9. Children's Family Drawings: A Study of Attachment, Personality, and Adjustment

    ERIC Educational Resources Information Center

    Goldner, Limor; Scharf, Miri

    2011-01-01

    This study examined the relationship between children's attachment security, as manifested in their family drawings, and their personality and adjustment. Family drawings were collected from 222 Israeli children, as well as data regarding their personality and adjustment. Each drawing was coded and classified into 1 of 4 attachment categories…

  10. Realistic Fiction and the Social Studies. Children's Literature.

    ERIC Educational Resources Information Center

    Mitchell-Powell, Brenda, Ed.

    1995-01-01

    Asserts that children's literature is an effective tool to access and present sophisticated social studies concepts in the elementary classroom. Maintains that realistic fiction can integrate the social sciences with philosophy and religion. Presents a bibliographic essay including children's books and teacher resources. (CFR)

  11. A Study of Biography as a Literary Form for Children.

    ERIC Educational Resources Information Center

    Taylor, M. Iona

    This study examined children's literature and the development of biography intended for juvenile readers. The writer assembled a list of characteristics of writing for children, reviewed the growth of biography as a literary form, and noted the difference between biography written for the child audience and that intended for adults. Qualities were…

  12. Improving Fine Motor Skills in Young Children: An Intervention Study

    ERIC Educational Resources Information Center

    Brown, Carol G.

    2010-01-01

    The aim of this study was to evaluate the effect of the Primary Movement programme on the fine motor skills of children in an early years setting in an area of high social disadvantage. Primary Movement is a programme which can be used as an early intervention technique to help children inhibit persistent primary reflexes that have been shown to…

  13. Children's Conceptions of the Word "Disabled": A Phenomenographic Study

    ERIC Educational Resources Information Center

    Skar, Lisa

    2010-01-01

    The aim of this study was to investigate the qualitative differences in children's conceptions of the word "disabled". Two hundred and thirty children, aged 7-12 years of age, were instructed to make a drawing of what came into their minds when they heard the word "disabled". A brief written commentary on their drawing was also…

  14. Executive Function Training in Children with SLI: A Pilot Study

    ERIC Educational Resources Information Center

    Vugs, Brigitte; Knoors, Harry; Cuperus, Juliane; Hendriks, Marc; Verhoeven, Ludo

    2017-01-01

    The aim of this study was to evaluate the effectiveness of a computer-based executive function (EF) training in children with specific language impairment (SLI). Ten children with SLI, ages 8 to 12 years, completed a 25-session training of visuospatial working memory, inhibition and cognitive flexibility over a 6-week period. Treatment outcome was…

  15. "Teacher" from the Children's Perspective: A Study by Metaphors

    ERIC Educational Resources Information Center

    Cansever, Belgin Arslan; Aslan, Nese

    2016-01-01

    The purpose of this study is to determine the perception of teachers by 10 year-old primary school childrens by the metaphors they developed. The sample covers totally 441 children [224 females (50.8%) and 217 males (49.2%)] living in Izmir, Turkey. Participants were asked to complete the prompt "Teacher is like..., because...''. In…

  16. Improving Children's Formal Word Definitions: A Feasibility Study

    ERIC Educational Resources Information Center

    Marinellie, Sally A.

    2010-01-01

    The ability to define a word with accuracy and precision is an important skill that has been associated with academic achievement. This study investigated the feasibility of conducting a lesson on formal word definitions to improve children's definitional production. The participants were 18 children in grade 4 (mean age: 9 years; 8 months) who…

  17. Facilitating Children's Self-Concept: A Rationale and Evaluative Study

    ERIC Educational Resources Information Center

    Hay, Ian

    2005-01-01

    This study reports on the design and effectiveness of the Exploring Self-Concept program for primary school children using self-concept as the outcome measure. The program aims to provide a procedure that incorporates organisation, elaboration, thinking, and problem-solving strategies and links these to children's multidimensional self-concept.…

  18. Mothers' Teaching Strategies and Children's Effortful Control: A Longitudinal Study

    ERIC Educational Resources Information Center

    Eisenberg, Nancy; Vidmar, Masa; Spinrad, Tracy L.; Eggum, Natalie D.; Edwards, Alison; Gaertner, Bridget; Kupfer, Anne

    2010-01-01

    Findings on the relation of maternal verbal teaching strategies to children's effortful control (EC; i.e., self-regulation) are limited in quantity and somewhat inconsistent. In this study, children's EC was assessed at 18, 30, and 42 months (ns = 255, 229, and 209, respectively) with adults' reports and a behavioral measure. Mothers' verbal…

  19. Analytical and numerical studies of photo-injected charge transport in molecularly-doped polymers

    NASA Astrophysics Data System (ADS)

    Roy Chowdhury, Amrita

    The mobility of photo-injected charge carriers in molecularly-doped polymers (MDPs) exhibits a commonly observed, and nearly universal Poole-Frenkel field dependence, mu exp√(beta0E), that has been shown to arise from the correlated Gaussian energy distribution of transport sites encountered by charges undergoing hopping transport through the material. Analytical and numerical studies of photo-injected charge transport in these materials are presented here with an attempt to understand how specific features of the various models developed to describe these systems depend on the microscopic parameters that define them. Specifically, previously published time-of-flight mobility data for the molecularly doped polymer 30% DEH:PC (polycarbonate doped with 30 wt.% aromatic hydrazone DEH) is compared with direct analytical and numerical predictions of five disorder-based models, the Gaussian disorder model (GDM) of Bassler, and four correlated disorder models introduced by Novikov, et al., and by Parris, et al. In these numerical studies, disorder parameters describing each model were varied from reasonable starting conditions, in order to give the best overall fit. The uncorrelated GDM describes the Poole-Frenkel field dependence of the mobility only at very high fields, but fails for fields lower than about 64 V/mum. The correlated disorder models with small amounts of geometrical disorder do a good over-all job of reproducing a robust Poole-Frenkel field dependence, with correlated disorder theories that employ polaron transition rates showing qualitatively better agreement with experiment than those that employ Miller-Abrahams rates. In a separate study, the heuristic treatment of spatial or geometric disorder incorporated in existing theories is critiqued, and a randomly-diluted lattice gas model is developed to describe the spatial disorder of the transport sites in a more realistic way.

  20. Nonlinear d--ta-f Simulation Studies of Intense Charged Particle Beams with Large Temperature Anisotropy

    SciTech Connect

    Edward A. Startsev; Ronald C. Davidson; Hong Qin

    2002-05-07

    In this paper, a 3-D nonlinear perturbative particle simulation code (BEST) [H. Qin, R.C. Davidson and W.W. Lee, Physical Review Special Topics on Accelerators and Beams 3 (2000) 084401] is used to systematically study the stability properties of intense nonneutral charged particle beams with large temperature anisotropy (T{sub {perpendicular}b} >> T{sub {parallel}b}). The most unstable modes are identified, and their eigen frequencies, radial mode structure, and nonlinear dynamics are determined for axisymmetric perturbations with {partial_derivative}/{partial_derivative}{theta} = 0.

  1. The Clinical Usefulness of Sleep Studies in Children.

    PubMed

    Oliveira, Virginia X Noronha; Teng, Arthur Y

    2016-01-01

    Sleep disordered breathing is common in children and has the potential to have a significant impact on cognition, activity and social interaction. The overnight in-laboratory polysomnography (PSG) continues to be the gold standard instrument for the investigation of sleep-disordered breathing in children. It has the ability to rule in or rule out the need for intervention for common conditions such as obstructive sleep apnoea, assess the role of sleep quality in children and adolescents with hypersomnolence, provide physiologic data in children with hypoventilation as may be seen in neuromuscular disease and assist in the assessment of children with structural airway and lung abnormalities. Polysomnography is valuable and the only reliable method to differentiate habitual snoring from many levels of sleep apnoea syndrome [1]. The American Academy of Paediatrics recommends that, in order to diagnose and manage OSA syndrome, all children should be screened for snoring and complex cases should be referred to a specialist. PSG is the diagnostic gold standard and adenotonsillectomy is the first line of treatment [2]. There is no evidence to support nap studies or ambulatory sleep studies in children [3]. With adequate staffing, expertise, and a child and family-friendly environment, children of any age can undergo a sleep study.

  2. Study of charge transfer complexes of [70]fullerene with phenol and substituted phenols.

    PubMed

    Bhattacharya, Sumanta; Banerjee, Shrabanti; Banerjee, Manas

    2005-07-01

    To improve the understanding of the charge transfer (CT) interaction of [70]fullerene with electron donors, interaction of [70]fullerene with a series of phenols, e.g., phenol, resorcinol and p-quinol were studied in 1,4-dioxan medium using absorption spectroscopy. An absorption band due to CT transition was observed in the visible region. The experimental CT transition energies (h nuCT) are well correlated (through Mulliken's equation) with the vertical ionisation potentials (I(D)v) of the series of phenols studied. From an analysis of this correlation degrees of charge transfer for the [70]fullerene-phenol complexes were estimated. The degrees of charge transfer in the ground state of the complexes have been found to be very low (<2%). The h nuCT values change systematically as the number and position of the -OH groups change on the aromatic ring of the phenol moiety. From the trends in the h nuCT values, the Hückel parameters (h(O) and k(C-O)) for the -OH group were obtained in a straightforward way and the values so obtained, viz., 1.91 and 1.0, respectively, are close to the ones (1.8 and 0.8) recommended by Streitwieser on the basis of other evidence. Oscillator strengths, transition dipole strengths and resonance energies of the [70]fullerene-phenol complexes were determined. Formation constants of the CT complexes were determined at four different temperatures from which enthalpies and entropies of formation of the complexes were estimated.

  3. STUDY DESIGN CONSIDERATIONS FOR THE EXPOSURE COMPONENT OF THE NATIONAL CHILDREN'S STUDY

    EPA Science Inventory

    An ideal strategy for the exposure monitoring component of the planned National Children's Study (NCS) is to measure indoor and outdoor concentrations and personal exposures of children to a variety of pollutants, including ambient particulate and gaseous pollutants, biologicals,...

  4. Changes in nuclear structure along the Mn isotopic chain studied via charge radii

    NASA Astrophysics Data System (ADS)

    Heylen, H.; Babcock, C.; Beerwerth, R.; Billowes, J.; Bissell, M. L.; Blaum, K.; Bonnard, J.; Campbell, P.; Cheal, B.; Day Goodacre, T.; Fedorov, D.; Fritzsche, S.; Garcia Ruiz, R. F.; Geithner, W.; Geppert, Ch.; Gins, W.; Grob, L. K.; Kowalska, M.; Kreim, K.; Lenzi, S. M.; Moore, I. D.; Maass, B.; Malbrunot-Ettenauer, S.; Marsh, B.; Neugart, R.; Neyens, G.; Nörtershäuser, W.; Otsuka, T.; Papuga, J.; Rossel, R.; Rothe, S.; Sánchez, R.; Tsunoda, Y.; Wraith, C.; Xie, L.; Yang, X. F.; Yordanov, D. T.

    2016-11-01

    The hyperfine spectra of 51,53 -64Mn were measured in two experimental runs using collinear laser spectroscopy at ISOLDE, CERN. Laser spectroscopy was performed on the atomic 3 d54 s25/2 6S →3 d54 s 4 p 3/2 6P and ionic 3 d54 s 5S2→3 d54 p 5P3 transitions, yielding two sets of isotope shifts. The mass and field shift factors for both transitions have been calculated in the multiconfiguration Dirac-Fock framework and were combined with a King plot analysis in order to obtain a consistent set of mean-square charge radii which, together with earlier work on neutron-deficient Mn, allow the study of nuclear structure changes from N =25 across N =28 up to N =39 . A clear development of deformation is observed towards N =40 , confirming the conclusions of the nuclear moments studies. From a Monte Carlo shell-model study of the shape in the Mn isotopic chain, it is suggested that the observed development of deformation is not only due to an increase in static prolate deformation but also due to shape fluctuations and triaxiality. The changes in mean-square charge radii are well reproduced using the Duflo-Zuker formula except in the case of large deformation.

  5. Children's environmental knowing: A case study of children's experiences during an environmental education programme

    NASA Astrophysics Data System (ADS)

    Scott, Sandra Anne

    This study explores children's experiences during WaterWorlds (pseudonym) a field-based environmental education programme at a marine science centre. The study objectives were to investigate how children understand and interpret their experiences, and how these experiences foster their environmental knowing. To address these objectives, I carried out a case study at a marine science centre in British Columbia. I examined children's WaterWorlds experiences and explored their environmental understandings and commitment to environmental action. I analysed the experiences of children in four separate classes and carried out an in-depth examination of four individual children. Data were collected using informal semi-structured interviews, observations, conversations, researcher journal logs, and student documents including their writing and illustrations. My findings indicate that the WaterWorlds programme experience fosters children's environmental knowing. Participation in WaterWorlds activities led to connection, caring, and concern for other species and in some cases, for the marine environment as a whole. During the programme, children chose the ways they interpreted and expressed their environmental knowledge, ethic of care, advocacy, and commitment to action. This development of each child's self-expression resulted in motivational and powerful learning experiences that inspired and nurtured their connections to the earth. This research provides evidence and examples of how educators can foster children's environmental knowing through multi-disciplinary environmental education experiences. It illustrates that activities such as observing and documenting the lives of other animal species, collecting data and conducting research on those species, and working and learning alongside experts in the field of environmental education are powerful experiences that motivate concern and care for the earth among children.

  6. Asthmatic children away from home: a comparative psychological study.

    PubMed

    Bentley, J

    1975-09-01

    The essential difference that emerged from a comparison of the fantasies of Rapidly Remitting and Nonremitting asthmatic children was found to be in the area of emotional awareness. The children who lost their asthmatic symptoms when separated from home were found to have some awareness of angry feelings toward parental figures whom they experienced as hostile and/or rejecting. They were also found to be aware, to some extent, of longings for a relationship with a person who would provide nurturing care or guidance. The Nonremitting children, on the other hand, were found to be lacking in any awareness of either angry feelings or longings for a nurturing relationship. A study of the test materials of both groups of children reveals that these feelings are present in all eight children. Yet they have been totally repressed in the Nonremitting children, while the Rapidly Remitting children have, apparently, not felt the need to resort to such massive repression. Thus a second area of difference, implied in the first, emerges when we compare these two groups of children in terms of defensive ego functioning. Abramson's emphasis on the central importance of the period in which the child's emotional conflict arose proved to be valid for this study. He predicted that those children whose asthma begins at or near the period of toilet training will be the same ones who will have most difficulty giving up their asthmatic symptoms. Although I have not been able to validate dates for onset of asthma, it's clear, I hope, from the foregoing discussion that the Nonremitting children all suffer from conflicts arising in the anal period of development. This is not so (or much less so) for the Rapidly Remitting children who, however, often have conflicts which are just as severe. Each of the Nonremitting children, on an unconscious level, is waging a battle with mother over who will get the upper hand: this is the central conflict. Though these children are outwardly compliant much

  7. Hyperactive Children: A Ten-Year Study

    ERIC Educational Resources Information Center

    Miller, James S.

    1978-01-01

    Available from: Arthur Retlaw and Associates, Inc., Suite 2080, 1603 Orrington Avenue, Evanston, Illinois 60201. A 10-year pediatric practice involving the observation of 290 children diagnosed as hyperactive led to the beliefs that hyperactivity is an emotional problem and that the child's inner state or family relationships should be central…

  8. Branching Out: Forest Studies with Children.

    ERIC Educational Resources Information Center

    Argast, Susan; Macdonald, Cheryl

    1995-01-01

    This is the second of a two-part integrated unit for teaching young children about trees and forests. In the first part, the authors presented activities to sharpen sensory awareness of trees. Here they present activities for examining the biological processes of trees and the ecological importance of forests. (LZ)

  9. Recent Advances in Computational Studies of Charge Exchange X-ray Emission

    NASA Astrophysics Data System (ADS)

    Cumbee, Renata

    2016-06-01

    Interest in astrophysical sources of charge exchange (CX) has grown since X-ray emission from comet Hyakutake was first observed, the origin of which is primarily due to CX processes between neutral species in the comet’s atmosphere and highly charged ions from the solar wind. More recent observations have shown that CX may have a significant contribution to the X-ray emission spectra of a wide variety of environments within our solar system including solar wind charge exchange (SWCX) with neutral gases in the heliosphere and in planetary atmospheres, as well as beyond the solar system in galaxy clusters, supernova remnants, and star forming galaxies.While the basic process of CX has been studied for many decades, the reliability of the existing data is not uniform, and the coverage of the astrophysically important projectile and target combinations and collisional velocities is insufficient. The need for reliable and robust CX X-ray emission models will only be amplified with the with the high resolution X-ray spectra expected from the soft X-ray imaging calorimeter spectrometer (SXS) onboard the Hitomi X-ray observatory. In this talk, I will discuss recent advances in theoretical CX cross sections and X-ray modeling with a focus on CX diagnostics. The need for experimental X-ray spectra and cross sections for benchmarking current theory will also be highlighted. This work was performed in collaboration with David Lyons, Patrick Mullen, David Schultz, Phillip Stancil, and Robin Shelton. Work at UGA was partially supported by NASA grant NNX09AC46G.

  10. Characterization of size, surface charge, and agglomeration state of nanoparticle dispersions for toxicological studies

    NASA Astrophysics Data System (ADS)

    Jiang, Jingkun; Oberdörster, Günter; Biswas, Pratim

    2009-01-01

    Characterizing the state of nanoparticles (such as size, surface charge, and degree of agglomeration) in aqueous suspensions and understanding the parameters that affect this state are imperative for toxicity investigations. In this study, the role of important factors such as solution ionic strength, pH, and particle surface chemistry that control nanoparticle dispersion was examined. The size and zeta potential of four TiO2 and three quantum dot samples dispersed in different solutions (including one physiological medium) were characterized. For 15 nm TiO2 dispersions, the increase of ionic strength from 0.001 M to 0.1 M led to a 50-fold increase in the hydrodynamic diameter, and the variation of pH resulted in significant change of particle surface charge and the hydrodynamic size. It was shown that both adsorbing multiply charged ions (e.g., pyrophosphate ions) onto the TiO2 nanoparticle surface and coating quantum dot nanocrystals with polymers (e.g., polyethylene glycol) suppressed agglomeration and stabilized the dispersions. DLVO theory was used to qualitatively understand nanoparticle dispersion stability. A methodology using different ultrasonication techniques (bath and probe) was developed to distinguish agglomerates from aggregates (strong bonds), and to estimate the extent of particle agglomeration. Probe ultrasonication performed better than bath ultrasonication in dispersing TiO2 agglomerates when the stabilizing agent sodium pyrophosphate was used. Commercially available Degussa P25 and in-house synthesized TiO2 nanoparticles were used to demonstrate identification of aggregated and agglomerated samples.

  11. The Charged Aerosol Release Experiment (Care II) to Study Artificial Dusty Plasmas in the Upper Atmosphere

    NASA Astrophysics Data System (ADS)

    Bernhardt, P. A.; Siefring, C. L.; Gatling, G.; Briczinski, S. J., Jr.; Vierinen, J.; Bhatt, A.; Holzworth, R. H., II; McCarthy, M.; Gustavsson, B.; La Hoz, C.; Latteck, R.

    2015-12-01

    A sounding rocket launched from Andoya, Norway in September 2015 carried 37 rocket motors and a multi-instrument daughter payload into the ionosphere to study the generation of plasma wave electric fields and ionospheric density disturbances by the high-speed injection of dust particles. The primary purpose of the CARE II mission is to validate the dress-particle theory of enhanced incoherent scatter from a dusty plasma and to validate models of plasma instabilities driven by high-speed charged particles. The CARE II chemical payload produces 66 kg of micron-sized dust particles composed of aluminium oxide. In addition to the dust, simple molecular combustion products such as N2, H2, CO2, CO, H20 and NO will be injected into the bottomside of the F-layer. Charging of the dust and ion charge exchange with the molecules yields plasma particles moving at hypersonic velocities. Streaming instabilities and shear electric fields causes plasma turbulence that can be detected using ground radars and in situ plasma instruments. The instrument payload was separated from the chemical release payload soon after launch to measure electric field vectors, electron and ion densities, and integrated electron densities from the rocket to the ground. The chemical release of high speed dust was directed upward on the downleg of the rocket trajectory to intersect the F-Layer. The instrument section was about 600 meters from the dust injection module at the release time. Ground HF and UHF radars were operated to detected scatter and refraction by the modified ionosphere. Optical instruments from airborne and ground observatories were used to map the dispersal of the dust using scattered sunlight. The plasma interactions are being simulated with both fluid and particle-in-cell (PIC) codes. CARE II is a follow-on to the CARE I rocket experiment conducted from Wallops Island Virginia in September 2009.

  12. Time-dependent quantum wave packet dynamics to study charge transfer in heavy particle collisions

    NASA Astrophysics Data System (ADS)

    Zhang, Song Bin; Wu, Yong; Wang, Jian Guo

    2016-12-01

    The method of time-dependent quantum wave packet dynamics has been successfully extended to study the charge transfer/exchange process in low energy two-body heavy particle collisions. The collision process is described by coupled-channel equations with diabatic potentials and (radial and rotational) couplings. The time-dependent coupled equations are propagated with the multiconfiguration time-dependent Hartree method and the modulo squares of S-matrix is extracted from the wave packet by the flux operator with complex absorbing potential (FCAP) method. The calculations of the charge transfer process 12Σ+ H-(1s2) +Li(1 s22 s ) →22Σ+ /32 Σ+ /12 Π H(1 s ) +Li-(1s 22 s 2 l ) (l =s ,p ) at the incident energy of about [0.3, 1.3] eV are illustrated as an example. It shows that the calculated reaction probabilities by the present FCAP reproduce that of quantum-mechanical molecular-orbital close-coupling very well, including the peak structures contributed by the resonances. Since time-dependent external interactions can be directly included in the present FCAP calculations, the successful implementation of FCAP provides us a powerful potential tool to study the quantum control of heavy particle collisions by lasers in the near future.

  13. Spectrophotometric and electrical studies of charge-transfer complexes of sodium flucloxacillin with π-acceptors

    NASA Astrophysics Data System (ADS)

    Refat, Moamen S.; El-Didamony, Akram M.

    2006-11-01

    The present study is interested to develop a simple, rapid and accurate spectrophotometric method for determination of sodium flucloxacillin (fluc) in pure form and pharmaceutical formulations. The charge-transfer (CT) interactions between sodium flucloxacillin as electron donor and chloranilic acid (CLA), dichloroquinone 4-chloroimide (DCQ), 2,3-dichloro-5,6-dicyano- p-benzoquinone (DDQ) and 7,7,8,8 tetracyano- p-quinodimethane (TCNQ), as π-electron acceptors have been investigated spectrophotometrically. Different variables affecting the reaction were studied and optimized. Under the optimum conditions, linear relationships with good correlation coefficients (0.9979-0.9995) were found between the absorbance and the concentration of the drug in the range 16-880 μg ml -1. The proposed methods were applied successfully to the determination of the examined drug either in pure or pharmaceutical dosage forms with good accuracy and precision. The formation of the CT-complexes and the sites of interaction were confirmed by elemental analysis CHN, UV-vis, IR, 1H NMR and mass spectra techniques. Based on Job's method of continuous variation plots, the obtained results indicate the formation of 1:1 charge-transfer complexes with the general formula [(fluc)(acceptor)]. Statistical analysis of the obtained results showed no significant difference between the proposed method and official method.

  14. Charge reduction in a vermiculite by acid and hydrothermal methods: a comparative study.

    PubMed

    Cristiano, D V; Campos, A M; Molina, R

    2005-10-13

    A comparative study on acid and hydrothermal methods as ways to reduce interlamellar charge has been carried out on a vermiculite. This study showed that the application of the hydrothermal treatment as a previous step to pillaring the vermiculites, reported here for the first time, is a new route to obtain the porous material with a particular interest as heterogeneous catalysts, starting from mineral clays with a high density of charge. Modified clays have been characterized by atomic absorption, emission spectrograph, X-ray diffraction, cation-exchange capacity, total acidity, infrared spectroscopy (DRIFT), and nitrogen adsorption. The results have shown that all solids have been structurally modified. However, acid and hydrothermal methods showed different behavior. For the vermiculite, the hydrothermal treatment did not produce major differences in terms of the crystalline structure, whereas the acid method caused severe structural damage. The catalytic properties have been tested over Pt-impregnated samples (1%) using the hydroisomerization of heptane. Important catalytic activity was established for all solids with high selectivity regarding the isomer products.

  15. Exiting Foster Care: A Case Study of Former Foster Children Enrolled in Higher Education in Kansas

    ERIC Educational Resources Information Center

    Schwandt, Jamie R.

    2013-01-01

    In the United States, foster care is provided to children to avert maltreatment and abuse of children in distressed families by providing a temporary home or a foster home. Courts with jurisdiction over families have been charged by Congress to find appropriate homes when necessary circumstances occur. In fiscal year 2009, there were 423,773…

  16. Five-frame, x-ray camera for charged particle, inertial confinement fusion studies.

    PubMed

    Fehl, D L; Chang, J; Kuswa, G W; Mendel, C W

    1980-03-01

    A prototype framing x-ray camera has been developed for photographic studies of inertial confinement fusion (ICF) targets irradiated by charged particle beams. Electron images from five, independently gated, microchannel plates are transported out of the radiation field by means of a toroidal magnetic field and are permanently recorded on film. The calculated, effective exposure time is studies have been made of luminous targets irradiated by pulsed electron and ion beams. The camera has also been adapted for single frame, x-radiographic studies of nonluminous imploding targets.

  17. Search for mutations altering protein charge and/or function in children of atomic bomb survivors: final report.

    PubMed

    Neel, J V; Satoh, C; Goriki, K; Asakawa, J; Fujita, M; Takahashi, N; Kageoka, T; Hazama, R

    1988-05-01

    A sample of (1) children whose parents had been proximally exposed (i.e., less than 2,000 m from the hypocenter) at the time of the atomic bombings of Hiroshima and Nagasaki and (2) a suitable comparison group have been examined for the occurrence of mutations altering the electrophoretic mobility or activity of a series of 30 proteins. The examination of the equivalent of 667,404 locus products in the children of proximally exposed persons yielded three mutations altering electrophoretic mobility; the corresponding figure for the comparison group was three mutations in 466,881 tests. The examination of a subset of 60,529 locus products for loss of enzyme activity in the children of proximally exposed persons yielded one mutation; no mutations were encountered in 61,741 determinations on the children of the comparison group. When these two series are compared, the mutation rate observed in the children of proximally exposed persons is thus 0.60 x 10(-5)/locus/generation, with 95% confidence intervals between 0.2 and 1.5 x 10(-5), and that in the comparison children is 0.64 x 10(-5)/locus/generation, with 95% intervals between 0.1 and 1.9 x 10(-5). The average conjoint gonad doses for the proximally exposed parents are estimated to be 0.437 Gy of gamma radiation and 0.002 Gy of neutron radiation. If a relative biological effectiveness of 20 is assigned to the neutron radiation, the combined total gonad dose for the parents becomes 0.477 Sv. (Organ absorbed doses are expressed in gray [1 Gy = 100 rad]; where dose is a mixture of gamma and neutron radiation, it is necessary because of the differing relative biological effectiveness of gamma and neutron radiation to express the combined gamma-neutron gonad exposures in sieverts [1 Sv = 100 rem]).

  18. Search for mutations altering protein charge and/or function in children of atomic bomb survivors: final report

    SciTech Connect

    Neel, J.V.; Satoh, C.; Goriki, K.; Asakawa, J.; Fujita, M.; Takahashi, N.; Kageoka, T.; Hazama, R.

    1988-05-01

    A sample of (1) children whose parents had been proximally exposed (i.e., less than 2000 m from the hypocenter) at the time of the atomic bombings of Hiroshima and Nagasaki and (2) a suitable comparison group have been examined for the occurrence of mutations altering the electrophoretic mobility or activity of a series of 30 proteins. The examination of the equivalent of 667,404 locus products in the children of proximally exposed persons yielded three mutations altering electrophoretic mobility; the corresponding figure for the comparison group was three mutations in 466,881 tests. The examination of a subset of 60,529 locus products for loss of enzyme activity in the children of proximally exposed persons yielded one mutation; no mutations were encountered in 61,741 determinations on the children of the comparison group. When these two series are compared, the mutation rate observed in the children of proximally exposed persons is thus 0.60 x 10(-5)/locus/generation, with 95% confidence intervals between 0.2 and 1.5 x 10(-5), and that in the comparison children is 0.64 x 10(-5)/locus/generation, with 95% intervals between 0.1 and 1.9 x 10(-5). The average conjoint gonad doses for the proximally exposed parents are estimated to be 0.437 Gy of gamma radiation and 0.002 Gy of neutron radiation. If a relative biological effectiveness of 20 is assigned to the neutron radiation, the combined total gonad dose for the parents becomes 0.477 Sv. (Organ absorbed doses are expressed in gray (1 Gy = 100 rad); where dose is a mixture of gamma and neutron radiation, it is necessary because of the differing relative biological effectiveness of gamma and neutron radiation to express the combined gamma-neutron gonad exposures in sieverts (1 Sv = 100 rem)).

  19. Psychological and electroencephalographic study in school children with iron deficiency.

    PubMed

    Otero, G A; Aguirre, D M; Porcayo, R; Fernández, T

    1999-08-01

    Two groups were chosen from a randomly selected group of one hundred 6-12 years old primary school children. One group was formed by iron deficient (ID), not anemic children, and a control group (C) by iron replete children. Both groups, matched by age, sex, and sociocultural level, were studied using WISC-R, a computerized test of learning (DEL) and a qEEG. The WISC-R test showed that ID children had significantly lower values in WISC items of information, comprehension and verbal, performance and full scale IQ than C children. On the other hand, the EEG power spectrum showed more theta energy in all leads using Laplacian montage and more delta energy in frontal areas using referential montage in ID than in C children. It was found that beside the well known effect of iron deficiency upon intellectual performance during childhood, the EEG power spectrum of ID children had a slower activity than in iron replete children suggesting a developmental lag and/or a CNS dysfunction.

  20. CHILDREN WITH EPILEPSY. A STUDY OF THEIR NEEDS IN CALIFORNIA.

    PubMed

    HOWARD, H E; FUJIKAWA, R

    1964-04-01

    The 1959 California Legislature directed the State Department of Public Health to conduct a study of the needs of California children with epilepsy and to determine the costs and feasibility of including medical services to such children under the Crippled Children Services program. A demonstration program of services was provided in Contra Costa and San Bernardino counties. Under these programs, children suspected of having epilepsy were referred for specialists' examinations, tests and recommendations for treatment. Private physicians provided the largest portion of a total of 236 referrals. Children referred were found to have complex medical, social and educational problems, and to be in need of comprehensive diagnostic and treatment services. About half of the children had mixed epilepsy and over one-third had focal seizures. Two-thirds had at least one other major additional handicap. At the time of referral one-fifth of these children had one or more seizures daily.Through specialized care and medications provided under this project, 58 per cent of those with seizures became seizure free, and an additional 24 per cent showed a considerable reduction of seizure frequency. This project provided a practical method of obtaining information necessary for program planning and has also demonstrated the value of such a program in helping private physicians to meet some of the multiple problems presented by these children.

  1. Hooking the Geographer in Children with Field-Based Studies

    ERIC Educational Resources Information Center

    Krall, Florence; And Others

    1978-01-01

    Suggests projects to help elementary students learn about man-land relationships through field experience, inquiry techniques, and a thematic, interdisciplinary approach. Children study a natural community, a human community, solid wastes, and energy conservation. (Author/AV)

  2. Autism Center First to Study Minimally Verbal Children

    MedlinePlus

    ... on. Feature: Taste, Smell, Hearing, Language, Voice, Balance Autism Center First to Study Minimally Verbal Children Past ... research exploring the causes, diagnosis, and treatment of autism spectrum disorder (ASD), a complex developmental disorder that ...

  3. Charge separation and charge recombination photophysical studies in a series of perylene-C60 linear and cyclic dyads.

    PubMed

    Pla, S; Niemi, M; Martín-Gomis, L; Fernández-Lázaro, F; Lemmetyinen, H; Tkachenko, N V; Sastre-Santos, Á

    2016-02-07

    A new donor–acceptor doubly bridged perylenediimide–fullerene dyad (PDI–C60, DB-3), where the perylenediimide (PDI) acts as a donor, has been synthesized and studied by time-resolved absorption spectroscopy. The DB-3 undergoes an electron transfer (ET) in both polar and non-polar media under photo-excitation. Structurally the DB-3 dyad resembles four other recently studied dyads (R. K. Dubey et al., Chem. Eur. J., 2013, 19, 6791–6806). Analysis of the ET reactions in this series of dyads was carried out in frame of both classic and semi-quantum ET theories. The result of the analysis for DB-3 suggests that the electronic coupling for the ET reaction is roughly 0.005 eV, internal reorganization energy is 0.16 eV, and outer sphere or solvent reorganization energy is 0.5 and 0.3 eV in benzonitrile and toluene, respectively.

  4. Depressive Symptoms among Children and Adolescents in Iran: A Confirmatory Factor Analytic Study of the Centre for Epidemiological Studies Depression Scale for Children

    ERIC Educational Resources Information Center

    Essau, Cecilia A.; Olaya, Beatriz; Pasha, Gholamreza; Gilvarry, Catherine; Bray, Diane

    2013-01-01

    This study investigated the psychometric properties of the Iranian translation of the Centre for Epidemiological Studies Depression Scale for Children (CES-DC) in school children and adolescents in Iran. The CES-DC is a 20-item self-report scale designed to measure depressive symptoms in children and adolescents. A total of 1,984 children and…

  5. Real-time charge carrier motion in P3HT studied with Kelvin Probe Microscopy

    NASA Astrophysics Data System (ADS)

    Castaneda, Chloe; Zaidi, Alyina; Moscatello, Jason; Aidala, Katherine

    We have developed a technique that uses scanning probe microscopy (SPM) to study the real-time injection and extraction of charge carriers in organic semiconductor devices. We investigate P3HT (full name) in an inverted field effect transistor geometry with gold electrodes. By positioning the SPM tip at an individual location and using Kelvin probe microscopy to record the potential over time, we can record how the charge carriers respond to changing the backgate voltage while the source and drain electrodes are grounded. We see relatively fast screening for negative backgate voltages because holes are quickly injected into the P3HT film. The screening is slower for positive gate voltages, because some of these holes are trapped and therefore less mobile. We compare P3HT transistors with different fabrication procedures that are expected to change the trap distribution: no silanization of the oxide and no annealing, silanization and no annealing, and both silanization and annealing. By incrementally stepping the gate voltage, we probe different trap depths. The recorded change in potential over time is best fit by a double exponential, suggesting two physical mechanisms involved in screening. This work is supported by NSF Grant DMR-0955348, and the Center for Heirarchical Manufacturing at the University of Massachusetts, Amherst (NSF CMMI-1025020).

  6. Negatively Charged Lipids as a Potential Target for New Amphiphilic Aminoglycoside Antibiotics: A BIOPHYSICAL STUDY.

    PubMed

    Sautrey, Guillaume; El Khoury, Micheline; Dos Santos, Andreia Giro; Zimmermann, Louis; Deleu, Magali; Lins, Laurence; Décout, Jean-Luc; Mingeot-Leclercq, Marie-Paule

    2016-06-24

    Bacterial membranes are highly organized, containing specific microdomains that facilitate distinct protein and lipid assemblies. Evidence suggests that cardiolipin molecules segregate into such microdomains, probably conferring a negative curvature to the inner plasma membrane during membrane fission upon cell division. 3',6-Dinonyl neamine is an amphiphilic aminoglycoside derivative active against Pseudomonas aeruginosa, including strains resistant to colistin. The mechanisms involved at the molecular level were identified using lipid models (large unilamellar vesicles, giant unilamelllar vesicles, and lipid monolayers) that mimic the inner membrane of P. aeruginosa The study demonstrated the interaction of 3',6-dinonyl neamine with cardiolipin and phosphatidylglycerol, two negatively charged lipids from inner bacterial membranes. This interaction induced membrane permeabilization and depolarization. Lateral segregation of cardiolipin and membrane hemifusion would be critical for explaining the effects induced on lipid membranes by amphiphilic aminoglycoside antibiotics. The findings contribute to an improved understanding of how amphiphilic aminoglycoside antibiotics that bind to negatively charged lipids like cardiolipin could be promising antibacterial compounds.

  7. A safety and tolerability study of differently-charged nanoparticles for local pulmonary drug delivery

    SciTech Connect

    Harush-Frenkel, Oshrat; Bivas-Benita, Maytal; Nassar, Taher; Springer, Chaim; Sherman, Yoav; Avital, Avraham; Altschuler, Yoram; Borlak, Jurgen; Benita, Simon

    2010-07-15

    Nanoparticle (NP) based drug delivery systems provide promising opportunities in the treatment of lung diseases. Here we examined the safety and tolerability of pulmonary delivered NPs consisting of PEG-PLA as a function of particle surface charge. The rationale for such a comparison should be attributed to the differential pulmonary toxicity of positively and negatively charged PEG-PLA NP. Thus, the local and systemic effects of pulmonary administered NPs were investigated following 5 days of daily endotracheal instillation to BALB/c mice that were euthanized on the eighth or nineteenth day of the experiment. We collected bronchoalveolar lavages and studied hematological as well as histochemistry parameters. Notably, the cationic stearylamine based PEG-PLA NPs elicited increased local and systemic toxic effects both on the eighth and nineteenth day. In contrast, anionic NPs of similar size were much better tolerated with local inflammatory effects observed only on the eighth experimental day after pulmonary instillation. No systemic toxicity effect was observed although a moderate change was noted in the platelet count that was not considered to be of clinical significance. No pathological observations were detected in the internal organs following instillation of anionic NPs. Overall these observations suggest that anionic PEG-PLA NPs are useful pulmonary drug carriers that should be considered as a promising therapeutic drug delivery system.

  8. Three-dimensional numerical studies of the temperature anisotropy instability in intense charged particle beams

    NASA Astrophysics Data System (ADS)

    Startsev, Edward A.; Davidson, Ronald C.; Qin, Hong

    2005-05-01

    In neutral plasmas with a uniform magnetic field and strongly anisotropic distribution function (T∥/T⊥≪1) an electrostatic Harris-type collective instability may develop if the plasma is sufficiently dense. Such anisotropies develop naturally in accelerators, and a similar instability may lead to a deterioration of the beam quality in a one-component nonneutral charged particle beam. The instability may also lead to an increase in the longitudinal velocity spread, which would make the focusing of the beam difficult and impose a limit on the minimum spot size achievable in heavy ion fusion experiments. This paper reports the results of recent numerical studies of the temperature anisotropy instability using the newly developed Beam Eigenmodes And Spectra (bEASt) code for space-charge-dominated, low-emittance beams with large tune depression (ν/ν0≪1). Such high-intensity beams are relevant to next-step experiments such as the Integrated Beam Experiment (IBX), which would serve as proof-of-principal experiment for heavy-ion fusion.

  9. Density functional study of the oxidation of small neutral and charged silver clusters.

    PubMed

    Pereiro, M; Botana, J; Baldomir, D; Serantes, D; Arias, J E

    2010-04-01

    We have studied the energetic and structural stability of the interaction of molecular oxygen with small neutral, anionic and cationic silver clusters, Ag(n) (3 < or = n < or = < 8). The calculations have been carried out using a linear combination of atomic Gaussian-type orbitals within the density functional theory as it is implemented in the demon-ks3.5 code. The O2 molecule has been placed in different positions surrounding the cluster, in order to increase the configurational space of the structural minima. We have found that the oxidized cation and neutral clusters undergo a 2D-3D structural transition even before than the nonoxidized counterparts. Moreover, our results show that the adsorption energies on the cationic and neutral silver oxide clusters manifest an odd-even alternation pattern. Likewise, the average magnetic moment of the O2 radical in the charged and neutral silver environment tends to be greater than the charged and neutral bare diatomic oxygen molecule.

  10. Experimental study of the stochastic heating of a single Brownian particle by charge fluctuations

    NASA Astrophysics Data System (ADS)

    Schmidt, Christian; Piel, Alexander

    2016-08-01

    The Brownian motion of a micro-particle, which is suspended in the sheath of a radio-frequency discharge, is studied by high-speed video microscopy. In this environment, stochastic heating by charge fluctuations is expected, which should lead to an anisotropic kinetic temperature of the particle with a preferential heating in the direction of the mean electric field in the sheath. The stochastic heating should become more effective at low gas pressures where cooling by the neutral gas becomes ineffective. Our refined experiments confirm the anisotropic heating and the temperature rise for diminishing pressure. Particle-in-cell simulations have guided us in modifying the gap width of the discharge and to specify the dependence of the plasma density on gas pressure as n i ∝ p 1 / 2 . Since the stochastic heating rate also depends on the life-time of charge fluctuations, a temperature scaling T kin ∝ p 3 / 2 results, which is in agreement with the experimental data. The experimental procedure to eliminate other spurious heating mechanisms is described in detail.

  11. Thermal charging study of compressed expanded natural graphite/phase change material composites

    SciTech Connect

    Mallow, Anne; Abdelaziz, Omar; Graham, Jr., Samuel

    2016-08-12

    The thermal charging performance of paraffin wax combined with compressed expanded natural graphite foam was studied for different graphite bulk densities. Constant heat fluxes between 0.39 W/cm2 and 1.55 W/cm2 were applied, as well as a constant boundary temperature of 60 °C. Thermal charging experiments indicate that, in the design of thermal batteries, thermal conductivity of the composite alone is an insufficient metric to determine the influence of the graphite foam on the thermal energy storage. By dividing the latent heat of the composite by the time to end of melt for each applied boundary condition, the energy storage performance was calculated to show the effects of composite thermal conductivity, graphite bulk density, and latent heat capacity. For the experimental volume, the addition of graphite beyond a graphite bulk density of 100 kg/m3 showed limited benefit on the energy storage performance due to the decrease in latent heat storage capacity. These experimental results are used to validate a numerical model to predict the time to melt and for future use in the design of heat exchangers with graphite-foam based phase change material composites. As a result, size scale effects are explored parametrically with the validated model.

  12. Thermal charging study of compressed expanded natural graphite/phase change material composites

    DOE PAGES

    Mallow, Anne; Abdelaziz, Omar; Graham, Jr., Samuel

    2016-08-12

    The thermal charging performance of paraffin wax combined with compressed expanded natural graphite foam was studied for different graphite bulk densities. Constant heat fluxes between 0.39 W/cm2 and 1.55 W/cm2 were applied, as well as a constant boundary temperature of 60 °C. Thermal charging experiments indicate that, in the design of thermal batteries, thermal conductivity of the composite alone is an insufficient metric to determine the influence of the graphite foam on the thermal energy storage. By dividing the latent heat of the composite by the time to end of melt for each applied boundary condition, the energy storage performancemore » was calculated to show the effects of composite thermal conductivity, graphite bulk density, and latent heat capacity. For the experimental volume, the addition of graphite beyond a graphite bulk density of 100 kg/m3 showed limited benefit on the energy storage performance due to the decrease in latent heat storage capacity. These experimental results are used to validate a numerical model to predict the time to melt and for future use in the design of heat exchangers with graphite-foam based phase change material composites. As a result, size scale effects are explored parametrically with the validated model.« less

  13. Numerical study of a novel induced-charge electrokinetic micro-mixer.

    PubMed

    Daghighi, Yasaman; Li, Dongqing

    2013-02-06

    A novel micro-mixer based on the induced-charge electrokinetic motion of an electrically conducting particle is proposed and numerically demonstrated in this paper. For most microfluidic applications, it is desired to mix different streams of solutions rapidly in a continuous flow mode. Therefore, in this work, we consider a mixing chamber containing an electrically conducting particle and the mixing chamber is located in the middle of a microchannel. Vortices are generated around the electrically conducting particle in an aqueous solution due to the interaction of the applied electric field and the induced surface charge on the particle. These vortices will enhance significantly the mixing of different solutions around the particle. The effectiveness of mixing the two streams entering the mixing chamber is numerically studied as functions of the applied electric field. Excellent mixing can be achieved in this system under two perpendicularly applied electric fields. The proposed micro-mixer is simple and easy to be fabricated for lab-on-a-chip applications.

  14. Experimental and modeling study on charge storage/transfer mechanism of graphene-based supercapacitors

    NASA Astrophysics Data System (ADS)

    Ban, Shuai; Jing, Xie; Zhou, Hongjun; Zhang, Lei; Zhang, Jiujun

    2014-12-01

    A symmetrical graphene-based supercapacitor is constructed for studying the charge-transfer mechanism within the graphene-based electrodes using both experiment measurements and molecular simulation. The in-house synthesized graphene is characterized by XRD, SEM and BET measurements for morphology and surface area. It is observed that the electric capacity of graphene electrode can be reduced by both high internal resistance and limited mass transfer. Computer modeling is conducted at the molecular level to characterize the diffusion behavior of electrolyte ions to the interior of electrode with emphasis on the unique 2D confinement imposed by graphene layers. Although graphene powder poses a moderate internal surface of 400 m2 g-1, the capacitance performance of graphene electrode can be as good as that of commercial activated carbon which has an overwhelming surface area of 1700 m2 g-1. An explanation to this abnormal correlation is that graphene material has an intrinsic capability of adaptively reorganizing its microporous structure in response to intercalation of ions and immergence of electrolyte solvent. The accessible surface of graphene is believed to be dramatically enlarged for ion adsorption during the charging process of capacitor.

  15. Charging and performance of the CubeSTAR satellite studied by numerical simulations

    NASA Astrophysics Data System (ADS)

    Miloch, Wojciech; Bekkeng, Tore André; Lindem, Torfinn

    2012-07-01

    A good understanding of spacecraft-plasma interaction is important for all space missions and experiments. The spacecraft potential is determined by the plasma, photoemission and other currents [1]. A charged object can significantly disturb the surrounding plasma, and lead to wake formation. The wake features, such as ion focusing, can influence the measurements of the plasma by the instruments onboard. A study of this problem using analytical models is difficult and can not account for all phenomena. This has encouraged use of numerical models for self-consistent studies of the plasma-object interactions on a detailed kinetic level [2][3]. With three-dimensional particle-in-cell (PIC) simulations [3][4], we address the spacecraft-plasma interaction in various plasma environments, and account for the self-consistent charging of the spacecraft by plasma and photoemission currents. As a specific case, we consider the interactions between plasma and a CubeSTAR satellite. CubeSTAR is a nano-satellite for the space weather studies being constructed in Norway, with the launch scheduled for year 2013. With a novel Langmuir probe system [5], it will measure the absolute electron densities with a high spatial resolution, allowing for studies of small scale plasma irregularities. We perform a systematic study of the role of the wakefield on the measurements with the Langmuir probes onboard the CubeSTAR for the plasma conditions relevant for the planned polar orbit. The simulation results are of relevance also for other spacecraft missions. [1] Whipple E C, Rep. Prog. Phys. 44, 1197 (1981). [2] Roussel J F and Berthelier J J, J. Geophys. Res. 109, A01104 (2004). [3] Yaroshenko V V et al., J. Geophys. Res. 116, A12218 (2011). [4] Miloch W J Kroll M and Block D 2010 Phys. Plasmas 17, 103703 (2010). [5] Bekkeng T A et al. Meas. Sci. Technol. 21, 085903 (2010).

  16. Study on temperature distribution effect on internal charging by computer simulation

    NASA Astrophysics Data System (ADS)

    Yi, Zhong

    2016-07-01

    Internal charging (or deep dielectric charging) is a great threaten to spacecraft. Dielectric conductivity is an important parameter for internal charging and it is sensitive to temperature. Considering the exposed dielectric outside a spacecraft may experience a relatively large temperature range, temperature effect can't be ignored in internal charging assessment. We can see some reporters on techniques of computer simulation of internal charging, but the temperature effect has not been taken into accounts. In this paper, we realize the internal charging simulation with consideration of temperature distribution inside the dielectric. Geant4 is used for charge transportation, and a numerical method is proposed for solving the current reservation equation. The conductivity dependences on temperature, radiation dose rate and intense electric field are considered. Compared to the case of uniform temperature, the internal charging with temperature distribution is more complicated. Results show that temperature distribution can cause electric field distortion within the dielectric. This distortion refers to locally considerable enlargement of electric field. It usually corresponds to the peak electric field which is critical for dielectric breakdown judgment. The peak electric field can emerge inside the dielectric, or appear on the boundary. This improvement of internal charging simulation is beneficial for the assessment of internal charging under multiple factors.

  17. Cerebrospinal fluid hydrodynamic studies in children.

    PubMed Central

    Blomquist, H K; Sundin, S; Ekstedt, J

    1986-01-01

    CSF-hydrodynamic investigation using the constant pressure infusion method was used in children. The CSF resting pressure was recorded and the CSF formation rate was measured. The conductance of the CSF outflow pathways and the pressure in the sagittal sinus were calculated. The method was used in children with suspicion of disturbed CSF hydrodynamics due to various neurological and other conditions. The method is applicable in paediatric neurological diagnostics and provides information for further understanding of the mechanisms behind cranial hypertension. The following mean values are offered as reference values in clinical work and in further research in this field: CSF-resting pressure 1.3 kPa, sagittal sinus pressure 1.1 kPa, pressure difference across arachnoid villi 0.5 kPa, conductance of CSF outflow pathways 22.6 mm3 kPa-1s-1, CSF formation rate 6.8 m3s-1. PMID:3711916

  18. Optical study of the multiple charge-density-wave transitions in ErTe3

    NASA Astrophysics Data System (ADS)

    Hu, B. F.; Cheng, B.; Yuan, R. H.; Dong, T.; Fang, A. F.; Guo, W. T.; Chen, Z. G.; Zheng, P.; Shi, Y. G.; Wang, N. L.

    2011-10-01

    We present an optical spectroscopy study on singe crystalline ErTe3, a rare-earth-element tritelluride, which experiences two successive charge-density wave (CDW) transitions at Tc1=267 K and Tc2=150 K. Two corresponding gap features, centered at 2770 cm-1 (˜343 meV) and 890 cm-1 (˜110 meV), respectively, are clearly seen in ordered state. A pronounced Drude component, which exists at all measurement temperatures, demonstrates the partial gap character of both CDW orders. About half of the unmodulated Fermi surface (FS) remains in the CDW state at the lowest measurement temperature. The study also indicates that fluctuation effect may be still prominent in this two-dimensional material.

  19. Spectroscopic studies of charge transfer complexes between colchicine and some π acceptors

    NASA Astrophysics Data System (ADS)

    Arslan, Mustafa; Duymus, Hulya

    2007-07-01

    Charge transfer complexes between colchicine as donor and π acceptors such as tetracyanoethylene (TCNE), 2,3-dichloro-5,6-dicyano- p-benzoquinone (DDQ), p-chloranil ( p-CHL) have been studied spectrophotometrically in dichloromethane at 21 °C. The stoichiometry of the complexes was found to be 1:1 ratio by the Job method between donor and acceptors with the maximum absorption band at a wavelength of 535, 585 and 515 nm. The equilibrium constant and thermodynamic parameters of the complexes were determined by Benesi-Hildebrand and van't Hoff equations. Colchicine in pure form and in dosage form was applied in this study. The formation constants for the complexes were shown to be dependent on the structure of the electron acceptors used.

  20. Charged vanadium-benzene multidecker clusters: DFT and quantum Monte Carlo study

    SciTech Connect

    Tokár, K.; Derian, R.; Mitas, L.; Štich, I.

    2016-02-14

    Using explicitly correlated fixed-node quantum Monte Carlo and density functional theory (DFT) methods, we study electronic properties, ground-state multiplets, ionization potentials, electron affinities, and low-energy fragmentation channels of charged half-sandwich and multidecker vanadium-benzene systems with up to 3 vanadium atoms, including both anions and cations. It is shown that, particularly in anions, electronic correlations play a crucial role; these effects are not systematically captured with any commonly used DFT functionals such as gradient corrected, hybrids, and range-separated hybrids. On the other hand, tightly bound cations can be described qualitatively by DFT. A comparison of DFT and quantum Monte Carlo provides an in-depth understanding of the electronic structure and properties of these correlated systems. The calculations also serve as a benchmark study of 3d molecular anions that require a balanced many-body description of correlations at both short- and long-range distances.

  1. Charged vanadium-benzene multidecker clusters: DFT and quantum Monte Carlo study.

    PubMed

    Tokár, K; Derian, R; Mitas, L; Štich, I

    2016-02-14

    Using explicitly correlated fixed-node quantum Monte Carlo and density functional theory (DFT) methods, we study electronic properties, ground-state multiplets, ionization potentials, electron affinities, and low-energy fragmentation channels of charged half-sandwich and multidecker vanadium-benzene systems with up to 3 vanadium atoms, including both anions and cations. It is shown that, particularly in anions, electronic correlations play a crucial role; these effects are not systematically captured with any commonly used DFT functionals such as gradient corrected, hybrids, and range-separated hybrids. On the other hand, tightly bound cations can be described qualitatively by DFT. A comparison of DFT and quantum Monte Carlo provides an in-depth understanding of the electronic structure and properties of these correlated systems. The calculations also serve as a benchmark study of 3d molecular anions that require a balanced many-body description of correlations at both short- and long-range distances.

  2. Studies of Photosynthetic Energy and Charge Transfer by Two-dimensional Fourier transform electronic spectroscopy

    NASA Astrophysics Data System (ADS)

    Ogilvie, Jennifer

    2010-03-01

    Two-dimensional (2D) Fourier transform electronic spectroscopy has recently emerged as a powerful tool for the study of energy transfer in complex condensed-phase systems. Its experimental implementation is challenging but can be greatly simplified by implementing a pump-probe geometry, where the two phase-stable collinear pump pulses are created with an acousto-optic pulse-shaper. This approach also allows the use of a continuum probe pulse, expanding the available frequency range of the detection axis and allowing studies of energy transfer and electronic coupling over a broad range of frequencies. We discuss several benefits of 2D electronic spectroscopy and present 2D data on the D1-D2 reaction center complex of Photosystem II from spinach. We discuss the ability of 2D spectroscopy to distinguish between current models of energy and charge transfer in this system.

  3. Transient absorption studies of the primary charge separation in photosystem II

    SciTech Connect

    Donovan, B.; Walker, L.A. II; Yocum, C.F.; Sension, R.J.

    1996-02-01

    Femtosecond transient absorption studies of the primary charge separation in photosystem II (PSII) are presented. A careful study of the dependence of the observed signal on laser intensity demonstrates that the multiple excitation of reaction centers produces additional fast components not observed at low excitation energy. In the regime where the observed signals are linear with excitation energy, a 20 {+-} 2 ps rise of the pheophytin anion absorption, bleach of the pheophytin Q{sub {chi}} absorption, and appearance of the chlorophyll cation absorption are observed. Three different protocols, involving varying exposure of the PSII complex to the detergent Triton X-100, are used to prepare D1-D2-cyt b{sub 559} complexes from spinach. The kinetic signals are independent of the method of sample preparation. 35 refs., 5 figs.

  4. Peer group status of gender dysphoric children: a sociometric study.

    PubMed

    Wallien, Madeleine S C; Veenstra, René; Kreukels, Baudewijntje P C; Cohen-Kettenis, Peggy T

    2010-04-01

    In this sociometric study, we aimed to investigate the social position of gender-referred children in a naturalistic environment. We used a peer nomination technique to examine their social position in the class and we specifically examined bullying and victimization of gender dysphoric children. A total of 28 children (14 boys and 14 girls), referred to a gender identity clinic, and their classmates (n = 495) were included (M age, 10.5 years). Results showed that the gender-referred children had a peer network of children of the opposite sex. Gender-referred boys had more nominations on peer acceptance from female classmates and less from male classmates as compared to other male classmates. Gender-referred girls were more accepted by male than by female classmates and these girls had significantly more male friends and less female friends. Male classmates rejected gender-referred boys more than other boys, whereas female classmates did not reject the gender-referred girls. For bullying and victimization, we did not find any significant differences between the gender-referred boys and their male classmates nor between the gender-referred girls and their female classmates. In sum, at elementary school age, the relationships of gender dysphoric children with opposite-sex children appeared to be better than with same-sex children. The social position of gender-referred boys was less favorable than that of gender-referred girls. However, the gender-referred children were not more often bullied than other children, despite their gender nonconforming behavior.

  5. Theoretical Studies of the Interaction of Excitons with Charged Impurities in Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Tayo, Benjamin O.

    A fundamental theory of the electronic and optical properties of semiconductors shows the importance of impurities, which are often unavoidable and can alter intrinsic properties of semiconductor materials substantially. While the subject of impurity doping is well understood in bulk semiconductors, the role and impact of doping in low dimensional materials like carbon nanotubes is still under investigation and there exists significant debate on the exact nature of electronic impurity levels in single-walled carbon nanotubes associated with adatoms. In this work, we address the role of impurities in single-walled carbon nanotubes. A simple model is developed for studying the interaction of bright (singlet) excitons in semiconducting single-wall nanotubes with charged impurities. The model reveals a red shift in the energy of excitonic states in the presence of an impurity, thus indicating binding of excitons in the impurity potential well. Signatures of several bound states were found in the absorption spectrum below the onset of excitonic optical transitions in the bare nanotube. The dependence of the binding energy on the model parameters, such as impurity charge and position, was determined and analytical fits were derived for a number of tubes of different diameter. The nanotube family splitting is seen in the diameter dependence, gradually decreasing with the diameter. By calculating the partial absorption coefficient for a small segment of nanotube the local nature of the wave function of the bound states was derived. Our studies provide useful insights into the role of the physical environment (here, a charged impurity atom) in the manipulation of the excited states of carbon nanotubes. We performed very detailed calculations of the electronic and optical properties of carbon nanotubes in the presence of an immobile impurity atom, thus going beyond previous many-body perturbation theory (MBPT) studies in which the carbon nanotubes were considered in vacuum

  6. A Multinational Study of Thromboprophylaxis Practice in Critically Ill Children*

    PubMed Central

    Faustino, Edward Vincent S.; Hanson, Sheila; Spinella, Philip C.; Tucci, Marisa; O'Brien, Sarah H.; Nunez, Antonio Rodriguez; Yung, Michael; Truemper, Edward; Qin, Li; Li, Simon; Marohn, Kimberly; Randolph, Adrienne G.

    2015-01-01

    Objectives Although critically ill children are at increased risk for developing deep venous thrombosis, there are few pediatric studies establishing the prevalence of thrombosis or the efficacy of thromboprophylaxis. We tested the hypothesis that thromboprophylaxis is infrequently used in critically ill children even for those in whom it is indicated. Design Prospective multinational cross-sectional study over four study dates in 2012. Setting Fifty-nine PICUs in Australia, Canada, New Zealand, Portugal, Singapore, Spain, and the United States. Patients All patients less than 18 years old in the PICU during the study dates and times were included in the study, unless the patients were 1) boarding in the unit waiting for a bed outside the PICU or 2) receiving therapeutic anticoagulation. Interventions None. Measurements and Main Results Of 2,484 children in the study, 2,159 (86.9%) had greater than or equal to 1 risk factor for thrombosis. Only 308 children (12.4%) were receiving pharmacologic thromboprophylaxis (e.g., aspirin, low-molecular-weight heparin, or unfractionated heparin). Of 430 children indicated to receive pharmacologic thromboprophylaxis based on consensus recommendations, only 149 (34.7%) were receiving it. Mechanical thromboprophylaxis was used in 156 of 655 children (23.8%) 8 years old or older, the youngest age for that device. Using nonlinear mixed effects model, presence of cyanotic congenital heart disease (odds ratio, 7.35; p < 0.001) and spinal cord injury (odds ratio, 8.85; p = 0.008) strongly predicted the use of pharmacologic and mechanical thromboprophylaxis, respectively. Conclusions Thromboprophylaxis is infrequently used in critically ill children. This is true even for children at high risk of thrombosis where consensus guidelines recommend pharmacologic thromboprophylaxis. PMID:24351371

  7. Revisit: High resolution charge density study of α-rhombohedral boron using third-generation SR data at SPring-8

    NASA Astrophysics Data System (ADS)

    Nishibori, Eiji; Hyodo, Hiroshi; Kimura, Kaoru; Takata, Masaki

    2015-09-01

    Experimental charge density of α-rhombohedral boron (α-B12) by a Maximum entropy method (MEM) has been re-investigated using the high resolution powder diffraction data measured at third-generation synchrotron radiation (SR) source, SPring-8. The present MEM charge density has many discrepancies from the previous MEM charge densities reported by Fujimori et al. and Hosoi et al. The data-resolution dependence of the MEM charge density was investigated using the present data. We found that diffraction data with d > 0.4 Å resolution range were needed to reveal qualitative bonding nature of α-B12 at 100 K. The peculiar bonding natures, such as a bend B-B bond and a propeller-shaped bond, which were found in the previous studies have disappeared by using d > 0.4 Å data. The bonding nature of MEM charge density using the full data with d > 0.327 Å d-spacing range is well agreed with those of theoretical calculations. The present study suggests that resolution test is important for an accurate charge density study of boron related materials.

  8. A microcalorimetric study of molecular interactions between immunoglobulin G and hydrophobic charge-induction ligand.

    PubMed

    Yuan, Xiao-Ming; Lin, Dong-Qiang; Zhang, Qi-Lei; Gao, Dong; Yao, Shan-Jing

    2016-04-22

    Hydrophobic charge-induction chromatography (HCIC) with 4-mercaptoethyl-pyridine (MEP) as the ligand is a novel technology for antibody purification. In this study, isothermal titration calorimetry (ITC) was used to evaluate the molecular interactions between MEP ligand and immunoglobulin G (IgG). Three types of IgG molecules including human IgG (hIgG), bovine IgG (bIgG) and a monoclonal antibody (mAb) were investigated with human serum albumins (HSA) and bovine serum albumin (BSA) as the comparison. The thermodynamic parameters obtained from ITC were compared with the adsorption data. The results indicated that MEP binding to protein at neutral pH was entropy driven and induced by multimodal molecular interactions that was dominated by hydrophobic forces. The interactions between MEP and IgGs were stronger than that of albumins, which resulted in high binding affinity of IgGs. Moreover, the effects of pH and salt addition on MEP-hIgG binding were studied. The change of enthalpy increased obviously with the decrease of pH, which revealed that the electrostatic forces dominated the MEP-hIgG interactions at acidic condition and caused typical charge-induced elution of HCIC. Salt addition influenced both hydrophobic and electrostatic interactions. With the increase of salt concentration, the hydrophobic interactions decreased first and then increased, while the electrostatic interactions showed the opposite trend. This resulted in trade-off between the multimodal interactions, which caused the salt-tolerant property of MEP resin. In general, ITC studies revealed the molecular mechanism of three critical characteristics of HCIC, multimodal interactions, pH-dependent and salt-tolerant properties.

  9. Polarization and charge limit studies of strained GaAs photocathodes

    SciTech Connect

    Saez, P.J.

    1997-03-01

    This thesis presents studies on the polarization and charge limit behavior of electron beams produced by strained GaAs photocathodes. These photocathodes are the source of high-intensity, high-polarization electron beams used for a variety of high-energy physics experiments at the Stanford Linear Accelerator Center. Recent developments on P-type, biaxially-strained GaAs photocathodes have produced longitudinal polarization in excess of 80% while yielding beam intensities of {approximately} 2.5 A/cm{sup 2} at an operating voltage of 120 kV. The SLAC Gun Test Laboratory, which has a replica of the SLAC injector, was upgraded with a Mott polarimeter to study the polarization properties of photocathodes operating in a high-voltage DC gun. Both the maximum beam polarization and the maximum charge obtainable from these photocathodes have shown a strong dependence on the wavelength of illumination, on the doping concentration, and on the negative electron affinity levels. The experiments performed for this thesis included studying the effects of temperature, cesiation, quantum efficiency, and laser intensity on the polarization of high-intensity beams. It was found that, although low temperatures have been shown to reduce the spin relaxation rate in bulk semiconductors, they don`t have a large impact on the polarization of thin photocathodes. It seems that the short active region in thin photocathodes does not allow spin relaxation mechanisms enough time to cause depolarization. Previous observations that lower QE areas on the photocathode yield higher polarization beams were confirmed. In addition, high-intensity, small-area laser pulses were shown to produce lower polarization beams. Based on these results, together with some findings in the existing literature, a new proposal for a high-intensity, high-polarization photocathode is given. It is hoped that the results of this thesis will promote further investigation on the properties of GaAs photocathodes.

  10. A pilot feasibility study of neurofeedback for children with autism.

    PubMed

    Steiner, Naomi J; Frenette, Elizabeth; Hynes, Caitlin; Pisarik, Elizabeth; Tomasetti, Kathryn; Perrin, Ellen C; Rene, Kirsten

    2014-06-01

    Neurofeedback (NFB) is an emerging treatment for children with autism spectrum disorder (ASD). This pilot study examined the feasibility of NFB for children with ASD. Ten children ages 7-12 with high functioning ASD and attention difficulties received a NFB attention training intervention. A standardized checklist captured feasibility, including focus during exercises and academic tasks, as well as off-task behaviors. Active behaviors and vocalizations were the most frequent off-task behaviors. Positive reinforcement and breaks including calm breathing exercises were the most common supports. Low motivation was associated with higher feasibility challenges, yet parental involvement and accommodations were helpful. This pilot study shows that it is feasible to conduct NFB sessions with children with high functioning autism and attention difficulties.

  11. Systematic studies on the effect of linear lattice optics for space-charge limited beams

    NASA Astrophysics Data System (ADS)

    Fitterer, M.; Carli, C.; Molodozhentsev, A.; Müller, A.-S.

    2015-12-01

    The HL-LHC (High Luminosity LHC) project aims to an increase of the luminosity of the LHC by a factor of 10. In order to realize this ambitious goal, the LHC itself has to undergo a major upgrade accompanied by an extensive upgrade of the complete injector complex referred to as LHC injector upgrade (LIU). In the framework of the LIU project, a new rapid cycling synchrotron (RCS) as an alternative to the energy upgrade of the existing PS Booster has been proposed. Motivated by the optics studies conducted for this RCS, the more general question of the influence of the linear optics on the machine performance has been raised. In this paper, we want to investigate this question by comparing different lattices with the final aim of identifying lattice characteristics advantageous under strong space-charge effects.

  12. Spectroscopic and thermodynamic study of charge transfer complexes of cloxacillin sodium in aqueous ethanol medium

    NASA Astrophysics Data System (ADS)

    Roy, Dalim Kumar; Saha, Avijit; Mukherjee, Asok K.

    2005-07-01

    Cloxacillin sodium has been shown to form charge transfer (CT) complexes of 1:1 stoichiometry with a number of electron acceptors in 50% (v/v) aqueous ethanol medium. From the trends in the CT absorption bands, the vertical ionization potential of the drug molecule (cloxacillin sodium) has been estimated to be 7.89 eV. The enthalpies and entropies of formation of two such complexes have been determined by estimating the formation constants spectrophotometrically at five different temperatures. The oscillator strengths and transition dipole moments of these complexes have been determined. It has further been noted that the reduction of o-chloranil by aqueous ethanol is completely inhibited by cloxacillin sodium, a phenomenon that makes the present study of formation equilibrium possible.

  13. Ion imaging study of dissociative charge transfer in the N2(+) + CH4 system.

    PubMed

    Pei, Linsen; Farrar, James M

    2013-03-28

    The velocity map ion imaging method is applied to the dissociative charge transfer reactions of N2(+) with CH4 studied in crossed beams. The velocity space images are collected at four collision energies between 0.5 and 1.5 eV, providing both product kinetic energy and angular distributions for the reaction products CH3(+) and CH2(+). The general shapes of the images are consistent with long range electron transfer from CH4 to N2(+) preceding dissociation, and product kinetic energy distributions are consistent with energy resonance in the initial electron transfer step. The branching ratio for CH3(+):CH2(+) is 85:15 over the full collision energy range, consistent with literature reports.

  14. Picosecond charge transport in rutile at high carrier densities studied by transient terahertz spectroscopy

    NASA Astrophysics Data System (ADS)

    Zajac, V.; Němec, H.; Kužel, P.

    2016-09-01

    We study terahertz photoconductivity of a rutile single crystal between 10 and 300 K under strong photoexcitation by femtosecond pulses at 266 nm. A marked dependence of the carrier mobility on the carrier density is observed leading to highly complex transport phenomena on a picosecond time scale. We develop a general model of carrier photoconductive response in the case of time dependent inhomogeneous distribution of carrier density and mobility. This allows us to assess an important role of both electrons and holes in the response of photoexcited rutile. At low temperatures, the carrier mobility is initially reduced due to the electron-hole scattering and increases by one order of magnitude upon ambipolar diffusion of the carriers into deeper regions of the sample. At room temperature, contributions of transient hot optical phonons and/or of midinfrared polaron excitations with charge-density-dependent dielectric strength emerge in the photoconductivity spectra.

  15. Ab initio study of nitrogen-multisubstituted neutral and positively charged C{sub 20} fullerene

    SciTech Connect

    Rani, Anita; Kumar, Ranjan

    2014-04-24

    Ab initio investigation of structural and electronic properties of Nitrogen doped fullerenes, obtained from C{sub 20} by replacing up to 10 C atoms with N atoms, are studied by means of first principals density functional theory calculations using numerical orbitals as basis sets. We have obtained the ground state structures for C{sub 20−n}N{sub n} for n=1-10. While substituting nitrogen atoms, we cannot substitute more than 9 nitrogen atoms. Nitrogen doping in C20 shows a significant change in density of states. For a better comparison with experimental measurements, we have also considered some positively charged ions and report the differences between properties of these ions and the corresponding neutral molecules.

  16. Dynamic light scattering studies on charged rod-like fd-virus in dilute aqueous solution

    NASA Astrophysics Data System (ADS)

    Schulz, Susanne F.; Maier, Erich E.; Krause, Rainer; Hagenbüchle, Martin; Deggelmann, Martin; Weber, Reinhart

    1990-06-01

    Time correlation functions of the scattered light intensity are studied in aqueous solutions of charged rod-like fd-virus (L=880 nm, d=6 nm) at various ionic strengths. The short time behavior of the correlation function is dominated by the static structure factor S(q) which is also independently determined from static light scattering experiments. Comparison of correlation functions of solutions with high ionic strength (screened Coulomb interaction) and those of solutions with liquid-like nearest neighbor order (strong Coulomb interaction) shows different single particle diffusion coefficients on medium time scales at high scattering vectors, where mainly single particle properties are observed by light scattering. The single particle diffusion coefficient decreases with increasing structure peak height of the solutions. At low scattering vectors an extra slow mode component of the correlation function is observed for solutions with Coulomb interaction.

  17. Kinetics study of crystallization with the disorder-bcc-fcc phase transition of charged colloidal dispersions.

    PubMed

    Zhou, Hongwei; Xu, Shenghua; Sun, Zhiwei; Du, Xuan; Liu, Lixia

    2011-06-21

    Structure transformation (disorder-bcc-fcc) in charged colloidal dispersions, as a manifestation of the Ostwald's step rule, was confirmed by means of reflection spectrum (RS) measurements in our previous study. By taking advantage of a reflection spectrum containing plenty of information about the crystallization behaviors, time-dependent changes of parameters associated with the crystal structure and composition during the disorder-bcc-fcc transition are reported by treating the data from RS in this article. In addition, Avrami's model is adopted to analyze the transition process and investigate the transition rate. On the basis of the above investigations, associated kinetic features of crystallization with the disorder-bcc-fcc transition are described.

  18. Charge-transfer chromatographic study of the interaction of antibiotics with sodium dodecylsulfate.

    PubMed

    Forgács, E; Csethati, T

    1997-06-01

    The interaction of 29 antibiotics with the anionic surfactant sodium dodecylsulfate (SDS) was studied by charge-transfer reversed-phase chromatography carried out on impregnated silica layers using water-methanol mixtures as eluents. The hydrophobicity of antibiotics and the relative strength of SDS-antibiotic interaction was calculated separately for each antibiotic-SDS pair. SDS interacted with 17 antibiotics where the antibiotic-SDS complex was either more hydrophilic or more hydrophobic than the uncomplexed molecule. The relative strength of interaction depended considerably on the molecular structure of the antibiotics. No significant linear correlation was found between the hydrophobicity parameters of antibiotics and their capacity to interact with SDS. Stepwise regression analysis proved that the inductive effect of substituents, their electron-withdrawing power and proton-acceptor capacity exert a significance influence on the strength of interaction.

  19. Study on space charge effect in an electrostatic ion analyzer applied to measure laser produced ions

    SciTech Connect

    Jin, Q. Y.; Li, Zh. M.; Liu, W.; Zhao, H. Y. Sha, S.; Zhang, J. J.; Zhang, X. Zh.; Sun, L. T.; Zhao, H. W.

    2014-03-15

    The abundance of different ions produced by laser ion sources is usually analyzed by an electrostatic ion analyzer (EIA). Ion current intensities in the range of several mA/cm{sup 2} at the position of the EIA have been achieved from the laser ion source developed by the Institute of Modern Physics; this indicates that a noticeable influence of space charge effect during the ion transmission will occur. Hence, while the parameters of the EIA or the beams are changed, such as ion species, current intensity, the ions’ transmission efficiency through the EIA is different, which will result in an uncertainty in the estimation of the ions’ yields. Special attention is focused on this issue in this paper. Ion's transmissions through the EIA under different circumstances are studied with simulations and experiments, the results of which are consistent with each other.

  20. Note: Multi channel Doppler tuned spectrometer to study highly charged ions.

    PubMed

    Karn, Ranjeet K; Mishra, C N; Ahmad, Nissar; Saini, S K; Safvan, C P; Nandi, T

    2014-06-01

    We describe the design and implementation of a multi channel Doppler tuned spectrometer setup to study physics of highly charged ions at high resolution in a direct way. A unique Soller slit assembly coupled with a long one dimensional position sensitive proportional counter enables us to get distinct x-ray peaks at different angles, which allows us to cover large number of angle in one shot. By using this setup, 1s2s (3)S1 - 1s(2) (1)S0 M1 transition in He-like Fe has been resolved from its satellite line 1s2s2p ⁴P(5/2)⁰ - 1s(2)2s (2)S(1/2) M2 transition in Li-like Fe and measured the lifetime of their respective upper levels with high precision.

  1. A comparative study of room temperature ionic liquids and their organic solvent mixtures near charged electrodes

    NASA Astrophysics Data System (ADS)

    Vatamanu, Jenel; Vatamanu, Mihaela; Borodin, Oleg; Bedrov, Dmitry

    2016-11-01

    The structural properties of electrolytes consisting of solutions of ionic liquids in a polar solvent at charged electrode surfaces are investigated using classical atomistic simulations. The studied electrolytes consisted of tetraethylammonium tetrafluoroborate (NEt4-BF4), 1-ethyl-3-methylimidazolium tetrafluoroborate (c2mim-BF4) and 1-octyl-3-methylimidazolium tetrafluoroborate (c8mim-BF4) salts dissolved in acetonitrile solvent. We discuss the influence of electrolyte concentration, chemical structure of the ionic salt, temperature, conducting versus semiconducting nature of the electrode, electrode geometry and surface roughness on the electric double layer structure and capacitance and compare these properties with those obtained for pure room temperature ionic liquids. We show that electrolytes consisting of solutions of ions can behave quite differently from pure ionic liquid electrolytes.

  2. A comparative study of the spontaneous social interactions of children with high-functioning autism and children with Asperger's disorder.

    PubMed

    Macintosh, Kathleen; Dissanayake, Cheryl

    2006-03-01

    A comparative observational study was undertaken of the spontaneous social interactions of children with high-functioning autism and Asperger's disorder. The sample comprised 20 children with high-functioning autism, 19 children with Asperger's disorder and 17 typically developing children matched on chronological age and overall mental age. A one-zero time sampling technique was used in live coding of the children's spontaneous social and play behaviours in the schoolyard. Few differences were found between children with high-functioning autism and Asperger's disorder on the dimensions of social interaction investigated. In contrast, the social behaviour of both clinical samples often deviated markedly from that of the typically developing children. The findings confirmed that although children with high-functioning autism or Asperger's disorder are often socially isolated relative to their typically developing peers, they are capable of spontaneously engaging socially with other children. The results were supportive of the hypothesis that Asperger's disorder is on a continuum with autistic disorder.

  3. [Comparative EEG study in normal and autistic children].

    PubMed

    Lushchekina, E A; Podreznaia, E D; Lushchekin, V S; Strelets, V B

    2010-01-01

    The work represents the results of a comparative study of spectral power as well as averaged coherence in alpha, beta and gamma EEG bands in 5-to-7-year-old autistic and healthy boys in the state of rest and under cognitive load (mental calculation). The mean age of the examined children was 6 years 4 months. In both healthy and autistic children, there was a clear-cut baseline frontal-occipital gradient of the alpha activity. Performance of the cognitive task led to enhancement of spectral power in the alpha1 band and shifting its maximum to the left hemisphere, did not change the activity in the alpha2 band, and considerably increased the spectral power in the alpha3 band. In healthy children, the spectral power and average coherence of the fast rhythms increased in the central and frontal areas of the left hemisphere. The right-side dominance of the spectral power of the alpha band was revealed in autistic children both in the baseline and during cognitive task. The spectral power of the gamma band was higher in autistic children than in healthy children in the baseline. The cognitive task did not change this fast activity in autistic children.

  4. Study of Mothers' Anxieties Related to Their Children's Future

    ERIC Educational Resources Information Center

    Ilgar, Sengul

    2015-01-01

    The purpose of this study is to study anxieties of mothers related to their children's future. Qualitative method was used in order to study anxieties of mothers from different socio-economic levels. Sample of the study participants are 129 mothers living in Istanbul. 32 of those mothers are from upper socio-economic level, 57, from middle…

  5. PRELIMINARY EXPOSURE ASSESSMENT FINDINGS FROM THE TAMPA ASTHMATIC CHILDREN'S STUDY

    EPA Science Inventory

    The Tampa Asthmatic Children's Study (TACS) was a pilot study that focused on developing and evaluating air pollution exposure assessment methods and participant recruiting tools. The four-week study was performed in October and November, 2003. The study involved repeated daily...

  6. EXPOSURE ASSESSMENT FINDINGS FROM THE TAMPA ASTHMATIC CHILDREN'S STUDY (TACS)

    EPA Science Inventory

    The Tampa Asthmatic Children's Study (TACS) was a pilot study that focused on developing and evaluating air pollution exposure assessment methods and participant recruiting tools. The four-week study was performed in October and November, 2003. The study involved repeated daily...

  7. Prospective studies on children with sex chromosome aneuploidy

    SciTech Connect

    Ratcliffe, S.G.; Paul, N.

    1986-01-01

    This book contains 11 selections. Some of the titles are: Growth and Development from Early to Midadolescence of Children with X and Y Chromosome Aneuploidy: The Toronto Study; Sex Chromomal Aneuploidy: Perspective and Longitudinal Studies; Psychologic Study of XYY and XXY Men; and Cellular and Molecular Studies in Human Chromosomal Diseases.

  8. A Prospective Study of Herpes Zoster in Children

    PubMed Central

    Katakam, Bhumesh Kumar; Kiran, Geeta; Kumar, Udaya

    2016-01-01

    Background: Herpes zoster (HZ) is a dermatomal viral infection, caused by reactivation of varicella zoster virus (VZV) that persists in the posterior root ganglion. HZ is uncommonly reported in immunocompetent children. It may be due to intrauterine VZV infection or secondary to postnatal exposure to VZV at an early age. Aims: Our study was to review clinico-epidemiological data for HZ in children for early diagnosis and treatment to prevent complications. Materials and Methods: A prospective observational study was conducted from January 2013 to December 2014. Consecutive cases clinically diagnosed as HZ in the pediatric age group were taken up. Results: We report the clinico-epidemiological study of 26 cases of HZ, their benign course and recovery among children. Conclusions: HZ is a rare disease in childhood. Varicella in early childhood is a risk factor of HZ in immunocompromised and immunocompetent children. Childhood zoster occurs in either healthy or underlying immunodeficient children. The appearance of HZ in a young child does not always imply an underlying immunodeficiency or malignancy. But the identification of HZ with or without immunodeficiency is of prime importance from the treatment and prognostic point of view and should be considered in the differential diagnosis of vesicular eruptions. The prognosis is generally good in healthy children. PMID:27688444

  9. Surface photovoltage studies of environmental influence on charge dynamics in nanostructured silicon

    NASA Astrophysics Data System (ADS)

    Chapagain, Puskar Raj

    Optoelectronic properties of nanoscale materials are significantly affected by their surfaces because of the presence of intrinsic and extrinsic electronic states in the bandgap. Thermally or optically driven charge exchange between the bulk and these states directly affects the surface band bending of these materials. Physisorption, chemisorption or desorption of environmental species at the surface also bring in additional modifications to the surface electronic structure, thereby, changing the surface potential barrier. The focus of this work was to investigate the influence of the environmental conditions on the surface band bending in nanoporous silicon (NPS), as well as some other nanostructured materials, using transient surface photovoltage---a non-destructive and highly surface-sensitive experimental probe. The potential barrier in NPS was monitored in a wide range of pressures, going down to high vacuum, and in a variety of gases. Due to the different rates of physisorption and chemisorption processes, we observed a coexistence of multiple components in the SPV transients occurring on different time scales and under different ambient conditions. We suggested a model elucidating the roles of intrinsic or extrinsic states in the surface transport properties of NPS. The importance of results is discussed in relation to potential applications of the studied materials in optoelectronic gas sensors. In order to distinguish between different surface charge transport processes affected by adsorption/desorption, we employed monochromatic illumination using several different wavelengths for selective excitation of these processes and compared these results with the ones observed for a polychromatic illumination containing both super- and sub-bandgap wavelengths. The scaling of transient SPV onset slopes in NPS vs. the excitation intensity was found to deviate from the linear dependence commonly observed in conventional bulk semiconductors. Considering drift- and

  10. Effects of Emotionally Charged Auditory Stimulation on Gait Performance in the Elderly: A Preliminary Study

    PubMed Central

    Rizzo, John-Ross; Raghavan, Preeti; McCrery, J.R.; Oh-Park, Mooyeon; Verghese, Joe

    2015-01-01

    Objectives To evaluate the effect of a novel divided attention task—walking under auditory constraints—on gait performance in older adults and to determine whether this effect was moderated by cognitive status. Design Validation cohort. Setting General community. Participants Ambulatory older adults without dementia (N=104). Interventions Not applicable. Main Outcome Measures In this pilot study, we evaluated walking under auditory constraints in 104 older adults who completed 3 pairs of walking trials on a gait mat under 1 of 3 randomly assigned conditions: 1 pair without auditory stimulation and 2 pairs with emotionally charged auditory stimulation with happy or sad sounds. Results The mean age of subjects was 80.6±4.9 years, and 63% (n=66) were women. The mean velocity during normal walking was 97.9±20.6cm/s, and the mean cadence was 105.1±9.9 steps/min. The effect of walking under auditory constraints on gait characteristics was analyzed using a 2-factorial analysis of variance with a 1-between factor (cognitively intact and minimal cognitive impairment groups) and a 1-within factor (type of auditory stimuli). In both happy and sad auditory stimulation trials, cognitively intact older adults (n=96) showed an average increase of 2.68cm/s in gait velocity (F1.86,191.71=3.99; P=.02) and an average increase of 2.41 steps/min in cadence (F1.75,180.42=10.12; P<.001) as compared with trials without auditory stimulation. In contrast, older adults with minimal cognitive impairment (Blessed test score, 5–10; n=8) showed an average reduction of 5.45cm/s in gait velocity (F1.87,190.83=5.62; P=.005) and an average reduction of 3.88 steps/min in cadence (F1.79,183.10=8.21; P=.001) under both auditory stimulation conditions. Neither baseline fall history nor performance of activities of daily living accounted for these differences. Conclusions Our results provide preliminary evidence of the differentiating effect of emotionally charged auditory stimuli on gait

  11. Phosphorus solubility of agricultural soils: a surface charge and phosphorus-31 NMR speciation study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated ten soils from six states in United States to determine the relationship between potentiometric titration derived soil surface charge and Phosphorus-31 (P) nuclear magnetic resonance (NMR) speciation with the concentration of water-extractable P (WEP). The surface charge value at the...

  12. Study of the top quark electric charge at the CDF experiment

    SciTech Connect

    Bartos, Pavol

    2011-01-01

    We report on the measurement of the top quark electric charge using the jet charge tagging method on events containing a single lepton collected by the CDF II detector at Fermilab between February 2002 and February 2010 at the center-of-mass energy √s = 1.96 TeV. There are three main components to this measurement: determining the charge of the W (using the charge of the lepton), pairing the W with the b-jet to ensure that they are from the same top decay branch and finally determining the charge of the b-jet using the Jet Charge algorithm. We found, on a sample of 5.6 fb-1 of data, that the p-value under the standard model hypothesis is equal to 13.4%, while the p-value under the exotic model hypothesis is equal to 0.014%. Using the a priori criteria generally accepted by the CDF collaboration, we can say that the result is consistent with the standard model, while we exclude an exotic quark hypothesis with 95% confidence. Using the Bayesian approach, we obtain for the Bayes factor (2ln(BF)) a value of 19.6, that favors very strongly the SM hypothesis over the XM one. The presented method has the highest sensitivity to the top quark electric charge among the presented so far top quark charge analysis.

  13. Assessment of Noise Exposure to Children: Considerations for the National Children's Study

    PubMed Central

    Viet, Susan Marie; Dellarco, Michael; Dearborn, Dorr G.; Neitzel, Richard

    2015-01-01

    Evidence has been accruing to indicate that young children are vulnerable to noise in their physical environment. A literature review identified that, in addition to hearing loss, noise exposure is associated with negative birth outcomes, reduced cognitive function, inability to concentrate, increased psychosocial activation, nervousness, feeling of helplessness, and increased blood pressure in children. While increasing attention has been given to the health effects of noise in children, research about noise exposure is sparse and often the measure of exposure is simply proximity to a noise source. The U.S. National Children's Study (NCS) provides a unique opportunity to investigate noise exposures to pregnant women and children using a number of assessment modalities at different life stages. Measurement of noise levels in homes and other environments, personal dosimetry measurements made over a period of days, and questionnaires addressing sources of noise in the environment, annoyance to noise, perceived noise level, use of head phones and ear buds, noisy activity exposures, and occupational exposures, are planned for evaluation within the NCS Vanguard pilot study. We describe the NCS planned approach to addressing noise exposure assessment in study visits over a child's lifetime. PMID:25866843

  14. Nonlinearity, resonance, charging, and motion at the atomic scale studied with scanning tunneling microscopes

    NASA Astrophysics Data System (ADS)

    Tu, Xiuwen

    2008-10-01

    Several novel phenomena at the single-atom and single-molecule level occurring on the surfaces of single crystals were studied with home-built low temperature scanning tunneling microscopes. The results revealed intriguing properties of single atoms and single molecules, including nonlinearity, resonance, charging, and motion. First, negative differential resistance (NDR) was observed in the dI/dV spectra for single copper-phthalocyanine (CuPc) molecules adsorbed on one- and two-layer sodium bromide (NaBr), but not for single CuPc molecules adsorbed on three-layer NaBr, all grown on a NiAl(110) surface. This transition from NDR to the absence of NDR was explained as the result of competing effects in the double-barrier tunnel junction (DBTJ) and was reproduced in a calculation based on a resonant-tunneling model. Second, the nonlinearity of the STM junction due to a single manganese (Mn) atom or MnCO molecule adsorbed on a NiAl(110) surface was used to rectify microwave irradiation. The resulting rectification current was shown to be sensitive to the spin-splitting of the electronic states of the Mn atom and to the vibrations of the MnCO molecule. Next, the ordering of cesium (Cs) atoms adsorbed on a Au(111) surface and a NiAl(110) surface was imaged in real space. Because of charge transfer to the substrates, Cs adatoms were positively charged on both surfaces. Even at 12 K, Cs adatoms were able to move and adjust according to coverage. On Au(111), the Cs first layer had a quasi-hexagonal lattice and islands of the second Cs layer did not appear until the first was completed. On NiAl(110), a locally disordered Cs first layer was observed before a locally ordered layer appeared at higher coverages. The cation-pi interactions were then studied at the single molecular level. We were able to form cation-pi complexes such as Cs···DSB, Cs···DSB···Cs, Rb···DSB, and Rb···ZnEtiol controllably by manipulation with the STM tip. We could also separate these

  15. The effect of charging rate on the graphite electrode of commercial lithium-ion cells: A post-mortem study

    DOE PAGES

    Somerville, L.; Bareno, J.; Trask, S.; ...

    2016-10-22

    Increased charging rates negatively affect the lifetime of lithium-ion cells by increasing cell resistance and reducing capacity. This work is a post-mortem study of 18650 cells subjected to charge rates of 0.7-, 2-, 4-, and 6-C. For cells charged at 0.7-C to 4-C, this performance degradation is primarily related to surface film thickness with no observable change in surface film chemical composition. However, at charge rates of 6-C, the chemical composition of the surface film changes significantly, suggesting that this change is the reason for the sharper increase in cell resistance compared to the lower charge rates. In addition, wemore » found that surface film formation was not uniform across the electrode. Surface film was thicker and chemically different along the central band of the electrode “jelly roll”. This result is most likely attributable to an increase in temperature that results from non-uniform electrode wetting during manufacture. As a result, this non-uniform change further resulted in active material delamination from the current collector owing to chemical changes to the binder for the cell charged at 6-C.« less

  16. The effect of charging rate on the graphite electrode of commercial lithium-ion cells: A post-mortem study

    SciTech Connect

    Somerville, L.; Bareno, J.; Trask, S.; Jennings, P.; McGordon, A.; Lyness, C.; Bloom, Ira

    2016-10-22

    Increased charging rates negatively affect the lifetime of lithium-ion cells by increasing cell resistance and reducing capacity. This work is a post-mortem study of 18650 cells subjected to charge rates of 0.7-, 2-, 4-, and 6-C. For cells charged at 0.7-C to 4-C, this performance degradation is primarily related to surface film thickness with no observable change in surface film chemical composition. However, at charge rates of 6-C, the chemical composition of the surface film changes significantly, suggesting that this change is the reason for the sharper increase in cell resistance compared to the lower charge rates. In addition, we found that surface film formation was not uniform across the electrode. Surface film was thicker and chemically different along the central band of the electrode “jelly roll”. This result is most likely attributable to an increase in temperature that results from non-uniform electrode wetting during manufacture. As a result, this non-uniform change further resulted in active material delamination from the current collector owing to chemical changes to the binder for the cell charged at 6-C.

  17. The effect of charging rate on the graphite electrode of commercial lithium-ion cells: A post-mortem study

    NASA Astrophysics Data System (ADS)

    Somerville, L.; Bareño, J.; Trask, S.; Jennings, P.; McGordon, A.; Lyness, C.; Bloom, I.

    2016-12-01

    Increased charging rates negatively affect the lifetime of lithium-ion cells by increasing cell resistance and reducing capacity. This work is a post-mortem study of 18650-type cells subjected to charge rates of 0.7-, 2-, 4-, and 6-C. For cells charged at 0.7-C to 4-C, this performance degradation is primarily related to surface film thickness with no observable change in surface film chemical composition. However, at charge rates of 6-C, the chemical composition of the surface film changes significantly, suggesting that this change is the reason for the sharper increase in cell resistance compared to the lower charge rates. In addition, we found that surface film formation was not uniform across the electrode. Surface film was thicker and chemically different along the central band of the electrode "jelly roll". This result is most likely attributable to an increase in temperature that results from non-uniform electrode wetting during manufacture. This non-uniform change further resulted in active material delamination from the current collector owing to chemical changes to the binder for the cell charged at 6-C.

  18. Ab initio studies of hyperconjugation effects on charge distribution in tetracyclododecane alcohols

    NASA Astrophysics Data System (ADS)

    Tostes, J. Glauco R.; Seidl, Peter Rudolf; Soto, M. M.; De M. Carneiro, J. W.; Lie, S. K.; Taft, C. A.; Brown, W.; Lester, W. A., Jr.

    1995-05-01

    Ab initio calculations using the STO-3G, 6-31G, and 6-31G ∗∗ basis sets are used to investigate charge distribution in tetracyclododecane alcohols. The calculated net atomic charges using fully optimized geometries indicate that certain carbon and hydrogen atoms in the proximity of a nonbonding oxygen lone pair are more negatively charged and the carbon-carbon and carbon-hydrogen bonds are longer. Analysis of these charges and bond lengths as well as atomic orbital populations suggests that the differences between charge distribution on carbon and hydrogen atoms adjacent to the hydroxyl group and their corresponding carbon-carbon and carbon-hydrogen bond lengths can be explained in terms of hyperconjugation.

  19. Spectrophotometric study of the charge transfer complexation of some porphyrin derivatives as electron donors with tetracyanoethylene.

    PubMed

    El-Zaria, Mohamed E

    2008-01-01

    Charge transfer complexes (CTC) of 5,10,15,20-tetraphenylporphyrin (TPP), 5,10,15,20-tetra(4-tolyl)porphyrin (TTP), 5,10,15,20-tetra(4-methoxyphenyl)porphyrin (TMP), Zn-5,10,15,20-tetraphenylporphyrin (Zn-TPP), and Zn-5,10,15,20-tetra(4-tolyl)porphyrin (Zn-TTP) with tetracyanoethylene (TCNE) have been studied at various temperatures in CH(2)Cl(2) and CCl(4). The data are discussed in terms of equilibrium constant (K(CT)), molar extinction coefficient (epsilon(CT)), thermodynamic standard reaction quantities (DeltaG degrees , DeltaH degrees and DeltaS degrees ), oscillator strength (f), and transition dipole moment (mu). The spectrum obtained for TPP/TCNE, TTP/TCNE, and TMP/TCNE systems shows two main absorption bands at 475 and 690nm, which are not due to the absorption of any of the reactants. These bands are characteristic of an intermolecular charge transfer involving the overlap of the lowest unoccupied molecular orbital (LUMO) of the acceptor with the highest occupied molecular orbital (HOMO) of the donor. The results reveal that the interaction between the donors and acceptor is due to pi-pi(*) transitions by the formation of radical ion pairs. The stoichiometry of the complexes was found to be 1:1 ratio by the Job and straight line methods between donors and acceptor with the maximum absorption bands at wavelengths of 475 and 690nm. The observed data show salvation effects on the spectral and thermodynamics properties of CTC. The ionization potential of the donors and the dissociation energy of the CTC were also determined and are found to be constant.

  20. Spectrophotometric study of the charge transfer complexation of some porphyrin derivatives as electron donors with tetracyanoethylene

    NASA Astrophysics Data System (ADS)

    El-Zaria, Mohamed E.

    2008-01-01

    Charge transfer complexes (CTC) of 5,10,15,20-tetraphenylporphyrin (TPP), 5,10,15,20-tetra(4-tolyl)porphyrin (TTP), 5,10,15,20-tetra(4-methoxyphenyl)porphyrin (TMP), Zn-5,10,15,20-tetraphenylporphyrin (Zn-TPP), and Zn-5,10,15,20-tetra(4-tolyl)porphyrin (Zn-TTP) with tetracyanoethylene (TCNE) have been studied at various temperatures in CH 2Cl 2 and CCl 4. The data are discussed in terms of equilibrium constant ( KCT), molar extinction coefficient ( ɛCT), thermodynamic standard reaction quantities (Δ G°, Δ H° and Δ S°), oscillator strength ( f), and transition dipole moment ( μ). The spectrum obtained for TPP/TCNE, TTP/TCNE, and TMP/TCNE systems shows two main absorption bands at 475 and 690 nm, which are not due to the absorption of any of the reactants. These bands are characteristic of an intermolecular charge transfer involving the overlap of the lowest unoccupied molecular orbital (LUMO) of the acceptor with the highest occupied molecular orbital (HOMO) of the donor. The results reveal that the interaction between the donors and acceptor is due to π-π * transitions by the formation of radical ion pairs. The stoichiometry of the complexes was found to be 1:1 ratio by the Job and straight line methods between donors and acceptor with the maximum absorption bands at wavelengths of 475 and 690 nm. The observed data show salvation effects on the spectral and thermodynamics properties of CTC. The ionization potential of the donors and the dissociation energy of the CTC were also determined and are found to be constant.

  1. Fluoroolefins as peptide mimetics: a computational study of structure, charge distribution, hydration, and hydrogen bonding.

    PubMed

    Urban, Joseph J; Tillman, Brendon G; Cronin, William Andrew

    2006-09-28

    The design of peptide mimetic compounds is greatly facilitated by the identification of functionalities that can act as peptide replacements. The fluoroalkene moiety has recently been employed for that purpose. The purpose of this work is to characterize prototypical fluoroalkenes (fluoroethylene and 2-fluoro-2-butene) with respect to key properties of peptides (amides) including structure, charge distribution, hydration, and hydrogen bonding. The results are compared to those obtained for model peptides (formamide, N-methylacetamide). Calculations have been carried out at the MP2 and B3LYP levels of theory with the 6-311++G(2d,p) and 6-311++G(2d,2p) basis sets. The results suggest that the fluoroalkene is similar in steric requirements to a peptide bond but that there is less charge separation. Calculations of the hydration free energies with the PCM bulk continuum solvent model indicate that the fluoroalkene has much smaller hydration free energies than an amide but that the difference in solvation free energy for cis and trans isomers is comparable. In studies of complexes with water molecules, the fluoroalkene is found to engage in interactions that are analogous to backbone hydrogen-bonding interactions that govern many properties of natural peptides and proteins but with smaller interaction energies. In addition, key structural differences are noted when the fluoroalkene is playing the role of hydrogen-bond acceptor which may have implications in binding, aggregation, and conformational preferences in fluoroalkene peptidomimetics. The issue of cooperativity in hydrogen-bonding interactions in complexes with multiple waters has also been investigated. The fluoroalkene is found to exhibit cooperative effects that mirror those of the peptide but are smaller in magnitude. Thus, pairwise addivitity of interactions appears to more adequately describe the fluoroalkenes than the peptides they are intended to mimic.

  2. Malnutrition Affects the Urban-Poor Disproportionately: A Study of Nigerian Urban Children of Different Socio-Economic Statuses

    PubMed Central

    Ejike, Chukwunonso E.C.C.

    2016-01-01

    Income inequality within the same place of residence may impact the nutritional status of children. This study therefore investigated the impact of income inequality on the nutritional status of children living in the same place of residence, using anthropometric tools. Children in four schools (Schools 1–4) within the vicinity of a housing estate in Umuahia, Nigeria, that charge fees making them ‘very affordable’, ‘affordable’, ‘expensive’ and ‘very expensive’, respectively, were recruited for the study. Thinness, overweight and obesity were defined using the Cole et al. reference standards. Thinness was present in 10.4% (13.0% of boys, 7.6% of girls); 20.4% (15.6% of boys, 27.3% of girls; and 0.7% (1.4% of boys, 0.0% of girls) of children in Schools 1–3, respectively; but absent in school 4. Only 3.7% (1.4% of boys, 6.1% of girls) and 5.6% (6.3% of boys, 4.5% of girls) of children in Schools 1 and 2, respectively, were overweight/obese. Conversely, 25.8% (18.9% of boys, 32.5% of girls) and 41.6% (38.8% of boys, 45.3% of girls) of children in Schools 3 and 4, respectively, were overweight/obese. The urban-poor (School 2) are clearly affected by malnutrition disproportionately. PMID:27669325

  3. A Study of the Ability of Intermediate-Grade Children to Draw Inferences from Selections of Children's Literature.

    ERIC Educational Resources Information Center

    Burgdorf, Arlene Bernice

    To assess children's ability to draw inferences from selections of children's literature and to measure the significance of various selected factors to this ability was the problem of this study. Children (432) were evenly divided among grades 4, 5, and 6 and randomly divided at each grade level into two equal groups, one of which read the…

  4. Hispanic parents of overweight and obese children and their outcome expectations for children's television viewing: A qualitative study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our objective was to explore parental outcome expectations (OE) regarding children's television (TV) viewing among parents of overweight or obese children. We conducted a qualitative study using semi-structured interviews with 20 parents of 5- to 8-year-old overweight or obese children. We found tha...

  5. Laboratory Studies of Charging Properties of Dust Grains in Astrophysical/Planetary Environments

    NASA Astrophysics Data System (ADS)

    Tankosic, D.; Abbas, M. M.

    2012-11-01

    Dust grains immersed in ambient plasmas and radiation, are charged and coupled to the plasma through electric and magnetic fields. Dust grains in various astrophysical/planetary environments are generally charged by: (a) photoelectric emissions with incident radiation at photon energies higher than the work function of the material and (b) sticking of low energy electrons and ions of the surrounding plasma or by secondary electron emissions induced by incident electrons/ions at sufficiently high energies. Consequenly, the particle charge is an important parameter that influences physical and dynamical processes in the interplanetary and interstellar medium, planetary rings, interstellar dust clouds, comets and the outer atmospheres of planets. The charging properties of individual micron-size dust grains are expected to be substantially different from the bulk materials. However, no viable models for calculation of the charging properties of individual micron size dust grains are available at the present time. Currently, very limited experimental data are available for charging of individual micron-size dust grains. In this paper we give a review of the results of the measurements on charging of analogs of the interstellar as well as Apollo 11 and 17 lunar dust grains carried out on the Electrodynamic Balance Facility at the NASA-MSFC.

  6. Using singing to nurture children's hearing? A pilot study.

    PubMed

    Welch, Graham F; Saunders, Jo; Edwards, Sian; Palmer, Zoe; Himonides, Evangelos; Knight, Julian; Mahon, Merle; Griffin, Susanna; Vickers, Deborah A

    2015-09-01

    This article reports a pilot study of the potential benefits of a sustained programme of singing activities on the musical behaviours and hearing acuity of young children with hearing impairment (HI). Twenty-nine children (n=12 HI and n=17 NH) aged between 5 and 7 years from an inner-city primary school in London participated, following appropriate ethical approval. The predominantly classroom-based programme was designed by colleagues from the UCL Institute of Education and UCL Ear Institute in collaboration with a multi-arts charity Creative Futures and delivered by an experienced early years music specialist weekly across two school terms. There was a particular emphasis on building a repertoire of simple songs with actions and allied vocal exploration. Musical learning was also supported by activities that drew on visual imagery for sound and that included simple notation and physical gesture. An overall impact assessment of the pilot programme embraced pre- and post-intervention measures of pitch discrimination, speech perception in noise and singing competency. Subsequent statistical data analyses suggest that the programme had a positive impact on participant children's singing range, particularly (but not only) for HI children with hearing aids, and also in their singing skills. HI children's pitch perception also improved measurably over time. Findings imply that all children, including those with HI, can benefit from regular and sustained access to age-appropriate musical activities.

  7. Young German children's early syntactic competence: a preferential looking study.

    PubMed

    Dittmar, Miriam; Abbot-Smith, Kirsten; Lieven, Elena; Tomasello, Michael

    2008-07-01

    Using a preferential looking methodology with novel verbs, Gertner, Fisher and Eisengart (2006) found that 21-month-old English children seemed to understand the syntactic marking of transitive word order in an abstract, verb-general way. In the current study we tested whether young German children of this same age have this same understanding. Following Gertner et al. (2006), one group of German children was tested only after they had received a training/practice phase containing transitive sentences with familiar verbs and the exact same nouns as those used at test. A second group was tested after a training/practice phase consisting only of familiar verbs, without the nouns used at test. Only the group of children with the training on full transitive sentences was successful in the test. These findings suggest that for children this young to succeed in this test of syntactic understanding, they must first have some kind of relevant linguistic experience immediately prior to testing--which raises the question of the nature of children's linguistic representations at this early point in development.

  8. An electron energy-loss study of picene and chrysene based charge transfer salts

    SciTech Connect

    Müller, Eric; Mahns, Benjamin; Büchner, Bernd; Knupfer, Martin

    2015-05-14

    The electronic excitation spectra of charge transfer compounds built from the hydrocarbons picene and chrysene, and the strong electron acceptors F{sub 4}TCNQ (2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane) and TCNQ (7,7,8,8-tetracyanoquinodimethan) have been investigated using electron energy-loss spectroscopy. The corresponding charge transfer compounds have been prepared by co-evaporation of the pristine constituents. We demonstrate that all investigated combinations support charge transfer, which results in new electronic excitation features at low energy. This might represent a way to synthesize low band gap organic semiconductors.

  9. Cu nuclear magnetic resonance study of charge and spin stripe order in La1.875Ba0.125CuO4

    NASA Astrophysics Data System (ADS)

    Pelc, D.; Grafe, H.-J.; Gu, G. D.; Požek, M.

    2017-02-01

    We present a Cu nuclear magnetic/quadrupole resonance study of the charge stripe ordered phase of LBCO, with detection of previously unobserved ("wiped-out") signal. We show that spin-spin and spin-lattice relaxation rates are strongly enhanced in the charge ordered phase, explaining the apparent signal decrease in earlier investigations. The enhancement is caused by magnetic, rather than charge fluctuations, conclusively confirming the long-suspected assumption that spin fluctuations are responsible for the wipeout effect. Observation of the full Cu signal enables insight into the spin and charge dynamics of the stripe-ordered phase, and measurements in external magnetic fields provide information on the nature and suppression of spin fluctuations associated with charge order. We find glassy spin dynamics, in agreement with previous work, and incommensurate static charge order with charge modulation amplitude similar to other cuprate compounds, suggesting that the amplitude of charge stripes is universal in the cuprates.

  10. Worries, 'weirdos', neighborhoods and knowing people: a qualitative study with children and parents regarding children's independent mobility.

    PubMed

    Crawford, S B; Bennetts, S K; Hackworth, N J; Green, J; Graesser, H; Cooklin, A R; Matthews, J; Strazdins, L; Zubrick, S R; D'Esposito, F; Nicholson, J M

    2017-03-27

    This qualitative study involved focus groups with 132 children and 12 parents in primary and secondary schools in metropolitan and regional areas of Victoria, Australia, to explore experiences and perceptions of children's independent mobility. The study highlights the impact of family routines, neighborhood characteristics, social norms and reference points for decision making. Children reported a wider range of safety concerns than parents, including harm from strangers or traffic, bullying, or getting lost. Children expressed great delight in being independent, often seeking to actively influence parents' decision making. Children's independent mobility is a developmental process, requiring graduated steps and skill building.

  11. Recurrent episodes of injury in children: an Australian cohort study.

    PubMed

    Cameron, Cate M; Spinks, Anneliese B; Osborne, Jodie M; Davey, Tamzyn M; Sipe, Neil; McClure, Roderick J

    2016-08-19

    Objective The aim of the present study was to compare sociodemographic characteristics of children with single versus recurrent episodes of injury and provide contemporary evidence for Australian injury prevention policy development.Methods Participants were identified from the Environments for Healthy Living: Griffith Birth Cohort Study 2006-11 (n=2692). Demographic data were linked to the child's hospital emergency and admissions data from birth to December 2013. Data were dichotomised in two ways: (1) injured or non-injured; and (2) single or recurrent episodes of injury. Multivariate logistic regression was used for analysis.Results The adjusted model identified two factors significantly associated with recurrent episodes of injury in children aged <3 years. Children born to mothers <25 years were almost fourfold more likely to have recurrent episodes of injury compared with children of mothers aged ≥35 years (adjusted odds ratio (aOR)=3.68; 95% confidence interval (CI) 1.44-9.39) and, as a child's age at first injury increased, odds of experiencing recurrent episodes of injury decreased (aOR=0.97; 95% CI 0.94-0.99). No differences were found in sociodemographic characteristics of children aged 3-7 years with single versus recurrent episodes of injury (P>0.1).Conclusion National priorities should include targeted programs addressing the higher odds of recurrent episodes of injury experienced by children aged <3 years with younger mothers or those injured in the first 18 months of life.What is known about the topic? Children who experience recurrent episodes of injury are at greater risk of serious or irrecoverable harm, particularly when repeat trauma occurs in the early years of life.What does the paper add? The present study identifies key factors associated with recurrent episodes of injury in young Australian children. This is imperative to inform evidence-based national injury prevention policy development in line with the recent expiry of the National

  12. A Sociocultural Perspective on Young Deaf Children's Fingerspelling: An Ethnographic Study in a Signing Setting

    ERIC Educational Resources Information Center

    Roos, Carin

    2014-01-01

    This study, which is part of a larger longitudinal ethnographic study of young deaf children, reports on deaf children's use of fingerspelling. The children observed were early signers using Swedish Sign Language (SSL) in communication with teachers and peers. This study centres on the functions of fingerspelling in the children's everyday…

  13. Hypnosis and dental anesthesia in children: a prospective controlled study.

    PubMed

    Huet, Adeline; Lucas-Polomeni, Marie-Madeleine; Robert, Jean-Claude; Sixou, Jean-Louis; Wodey, Eric

    2011-01-01

    The authors of this prospective study initially hypothesized that hypnosis would lower the anxiety and pain associated with dental anesthesia. Thirty children aged 5 to 12 were randomly assigned to 2 groups receiving hypnosis (H) or not (NH) at the time of anesthesia. Anxiety was assessed at inclusion in the study, initial consultation, installation in the dentist's chair, and at the time of anesthesia using the modified Yale preoperative anxiety scale (mYPAS). Following anesthesia, a visual analogue scale (VAS) and a modified objective pain score (mOPS) were used to assess the pain experienced. The median mYPAS and mOPS scores were significantly lower in the H group than in the NH group. Significantly more children in the H group had no or mild pain. This study suggests that hypnosis may be effective in reducing anxiety and pain in children receiving dental anesthesia.

  14. Electron excited multiply charged argon ions studied by means of an energy resolved electron-ion coincidence technique

    NASA Astrophysics Data System (ADS)

    Kumar, Sunil; Prajapati, Suman; Singh, Bhupendra; Singh, Bhartendu Kumar; Shanker, Rama

    2017-03-01

    Multiply charged argon ions produced from decay of L-shell hole states by impact of a continuous beam of 3.5 keV electrons are studied for the first time using an energy resolved electron-ion coincidence technique. The TOF spectra of argon ions are measured in coincidence with 18-energy selected electrons emitted in a wide energy range (126-242 eV). The coincidence measurement between the energy selected electrons and the correlated ions specifies the individual decay channel for various multiply charged ions. New experimental data are obtained and reported on the correlation probability for production of argon ions with charge states 1+ to 4+ as a function of ejected electrons in the considered energy range. The relative correlation probability of producing different charge state ions and corresponding physical processes involved in their production are presented and discussed. It has been found that the maximum probability for production of Ar2+ ions correlated to ejected Auger electrons in the energy range of 205-209 eV is 100%. No theoretical predictions are available to compare with these results. The present study shows further that not only the auto-ionization and normal Auger transitions but also several other decay processes including Coster-Kronig transitions followed by Auger cascades with a fraction of shake process play important role in producing ions with charge states 1+ to 4+.

  15. Accounting for changes in particle charge, dry mass and composition occurring during studies of single levitated particles.

    PubMed

    Haddrell, Allen E; Davies, James F; Yabushita, Akihiro; Reid, Jonathan P

    2012-10-11

    The most used instrument in single particle hygroscopic analysis over the past thirty years has been the electrodynamic balance (EDB). Two general assumptions are made in hygroscopic studies involving the EDB. First, it is assumed that the net charge on the droplet is invariant over the time scale required to record a hygroscopic growth cycle. Second, it is assumed that the composition of the droplet is constant (aside from the addition and removal of water). In this study, we demonstrate that these assumptions cannot always be made and may indeed prove incorrect. The presence of net charge in the humidified vapor phase reduces the total net charge retained by the droplet over prolonged levitation periods. The gradual reduction in charge limits the reproducibility of hygroscopicity measurements made on repeated RH cycles with a single particle, or prolonged experiments in which the particle is held at a high relative humidity. Further, two contrasting examples of the influence of changes in chemical composition changes are reported. In the first, simple acid-base chemistry in the droplet leads to the irreversible removal of gaseous ammonia from a droplet containing an ammonium salt on a time scale that is shorter than the hygroscopicity measurement. In the second example, the net charge on the droplet (<100 fC) is high enough to drive redox chemistry within the droplet. This is demonstrated by the reduction of iodic acid in a droplet made solely of iodic acid and water to form iodine and an iodate salt.

  16. THE NATIONAL CHILDREN'S STUDY: PROGRESS DEVELOPING METHODS APPROPRIATE FOR ASSESSING CHILDREN'S EXPOSURE, BIOMARKERS AND GENETIC SUSCEPTIBILITY

    EPA Science Inventory

    Invited presentation: no abstract submission fee required
    Introduction abstract for Workshop.

    CONTROL ID: 56947
    CONTACT (NAME ONLY): Barbara Abbott
    Abstract Details
    PRESENTATION TYPE: Invited Presentation : Workshop
    KEYWORDS: National Childrens Study, Ri...

  17. Winter Nature Study for Middle School Children and Their Parents. A Course for Parents and Children.

    ERIC Educational Resources Information Center

    Sigford, Ann

    Designed to be a supplement to a short course for middle school children and their parents, this document provides learning experiences for studying ecology during the winter. The purposes of the course are to introduce families to the pleasures of outdoor field exploration and to give them a basic ecological framework as well as specific skills…

  18. The National Children's Study in North Carolina: a study of the effect of the environment on children's health, growth, and development.

    PubMed

    Walter, Emmanuel B; Dole, Nancy; Siega-Riz, Anna Maria; Entwisle, Barbara

    2011-01-01

    The National Children's Study, a longitudinal cohort study exploring relationships among broadly defined environmental exposures and children's health, is assessing whether these exposures are harmful, harmless, or helpful. The study is presently underway in 37 locations (2 of which are in North Carolina) and will expand to enroll 100,000 children across the United States.

  19. Study of fluorescence characteristics of the charge-transfer reaction of quinolone agents with bromanil

    NASA Astrophysics Data System (ADS)

    Li, Wen-Ying; Chen, Xiao-Fang; Xuan, Chun-Sheng

    2009-01-01

    A spectrofluorimetric method was discussed for the determination of three antibacterial quinolone derivatives, ofloxacin (OFL), norfloxacin (NOR) and ciprofloxacin (CIP) through charge-transfer complexation (CTC) with 2,3,5,6-tetrabromo-1,4-benzoquinone (bromanil, TBBQ). The method was based on the reaction of these drugs as n-electron donors with the π-acceptor TBBQ. TBBQ was found to react with these drugs to produce a kind of yellow complexes and the fluorescence intensities of the complexes were enhanced by 29-36 times more than those of the corresponding monomers. UV-vis, 1H NMR and XPS techniques were used to study the complexes formed. The various experimental parameters affecting the fluorescence intensity were studied and optimized. Under optimal reaction conditions, the rectilinear calibration graphs were obtained in the concentration range of 0.021-2.42 μg mL -1, 0.017-2.63 μg mL -1 and 0.019-2.14 μg mL -1 for OFL, NOR and CIP, respectively. The methods developed were applied successfully to the determination of the subject drugs in their pharmaceutical dosage forms with good precision and accuracy compared to official and reported methods as revealed by t- and F-tests.

  20. Femtosecond Heterodyne Transient Grating Spectroscopic Studies of Intramolecular Charge Transfer Character of Peridinin and Peridinin Analogs

    NASA Astrophysics Data System (ADS)

    Bishop, Michael; Khosravi, Soroush; Obaid, Razib; Whitelock, Hope; Carroll, Ann Marie; Lafountain, Amy; Frank, Harry; Beck, Warren; Gibson, George; Berrah, Nora

    2016-05-01

    The peridinin chlorophyll-a protein is a light harvesting complex found in several species of dinoflagellates. Peridinin absorbs strongly in the mid-visible spectral region and, despite the lack of a strong permanent dipole moment in its lowest energy excited state, is able to transfer excitation energy quickly and efficiently to chlorophyll-a. It is believed that the high efficiency arises from the development of intramolecular charge-transfer (ICT) character upon photoexcitation. Recently, heterodyne transient grating spectroscopy has been used to study the ultrafast (<50 fs) dynamics of β carotene and peridinin. The studies show evidence for a structurally displaced intermediate in both cases and strong ICT character in the case of peridinin, but up to now the work has not provided appropriate control experiments. The present experiments examine peridinin and two peridinin analogs, S1-peridinin and S2-peridinin. S1-peridinin is reported to have greatly diminished ICT character, and S2-peridinin is reported to have little-or-no ICT character. Heterodyne transient grating data will be presented and provide a more unambiguous characterization spectral and kinetic properties associated with the peridinin ICT state. Funded by the DoE-BES, Grant No. DE-SC0012376.

  1. [Sports injuries in children. Epidemiologic study].

    PubMed

    Du Boullay, C T; Bardier, M; Cheneau, J; Bortolasso, J; Gaubert, J

    1984-01-01

    Among 49 000 cases of infantile emergencies which were received in the BUCI (Bloc d'urgence chirurgical infantile: surgical infantile emergency unit), 5 546 were sport traumas. At an early age, they were caused by outdoor plays; during adolescence, the main cases were caused by team sports. Males are predominant. The number of cases has been regularly progressing, particularly since 1976. The fashion in sports is influenced by médias (i.e. skate board), and can be opposed to the continuous practice of popular sports (swimming, ball games, bycicle. There are winter, summer, school timed sports (the latter being influenced by the sportive scholar associations). The most frequent sports are cycling, football playing, swimming and horse riding, athleticism skating, Other are occasionnal. Changes in sport fashions, female increasing participation, such as horse riding and skating, democratisation (skiing, riding), the worsening of traumas; the pathology concerning bystanders, are described. Cranial and peripheric pathology are dominant. Trunk traumas are scarce but severe. Each sport has an elective pathologic localisation. Injury mechanisms are found, such as stirrup, saddle, ski baton pathology. There is traumatologic similarities; skate board and roller skating; judo and atheleticism; cycling and horse riding. Sport in children is not a replica of the one among adults. Riding a bike is not cycling. Some sports are dangerous: cycling, horse riding, rugby. A traumatological outline is revealed. Preventive measures should be taken. The socio-economical cost is heavy.

  2. A Major Children's Educational Art Exhibit: An Evaluative Case Study.

    ERIC Educational Resources Information Center

    Schlenk, George W.; Shrock, Sharon A.

    Results of a case study of an exhibit of art and artifacts designed for children are presented. The focus of the study was to apply the principles of instructional-message design to the evaluation of the exhibit. The exhibit, "Art Inside Out: Exploring Art and Culture through Time," was displayed at the Art Institute of Chicago. Textual…

  3. Children as Educational Computer Game Designers: An Exploratory Study

    ERIC Educational Resources Information Center

    Baytak, Ahmet; Land, Susan M.; Smith, Brian K.

    2011-01-01

    This study investigated how children designed computer games as artifacts that reflected their understanding of nutrition. Ten 5th grade students were asked to design computer games with the software "Game Maker" for the purpose of teaching 1st graders about nutrition. The results from the case study show that students were able to…

  4. Time-resolved optical studies of colossal magnetoresistance and charge-density wave materials

    NASA Astrophysics Data System (ADS)

    Ren, Yuhang

    This thesis presents measurements of collective modes and ultrafast carrier relaxation dynamics in charge-density-wave (CDW) conductors and colossal magnetoresistance (CMR) manganites. A femtosecond laser pump pulse excites a broad frequency spectrum of low-energy collective modes and electron-hole pairs thereby changing its optical properties. The low-energy collective excitations and quasiparticle relaxation and recombination processes are monitored by measuring the resulting photoinduced absorption as a function of probe pulse wavelength and time delay. A general model was developed for the photogeneration and detection mechanism of collective modes based on light absorption in two-color pump-probe experiments. A broad spectrum of collective modes (phasons and amplitudons) with frequencies down to a few GHz is excited and propagates normal to the surface into the material. The dispersion of the long-wavelength phason and amplitudon can be measured by changing the probe wavelength. The first pump-probe spectroscopy was performed from the ultraviolet to mid-infrared wavelength range to study low-frequency collective excitations, including temperature evolution, dispersion, damping, and anisotropy of amplitude mode and transverse phason in quasi-one dimensional CDW conductors, K 0.3MoO3 and K0.33MoO3 on ultrafast time scale. The transverse phason exhibits an acoustic-like dispersion relation in the frequency range from 5--40 GHz. The phason velocity is strongly anisotropic with a very weak temperature dependence. In contrast, the amplitude mode exhibits a weak (optic-like) dispersion relation with a frequency of 1.66 THz at 30 K. The studies were extended to doped perovskite manganite thin films and single crystals. A low-energy collective mode is observed and discussed in terms of the opening of a pseudogap resulting from charge/orbital ordering phases. The softening of the collective mode is necessary to explain by combining a cooperative Jahn-Teller type

  5. Heteroleptic cyclometalated Ir(III) complexes with charge transporting groups: A theoretical study

    SciTech Connect

    Padmaperuma, Asanga B.; Fernandez, Carlos A.

    2012-09-13

    Efficient and stable high energy organic light emitting devices (OLEDs) are a vital component of new generation general illumination solutions. However, large charge imbalances in the emissive layer of OLEDs lead to charge accumulation and subsequent side reactions which lowers the device efficiency and dramatically shortens operational lifetime. Radical changes in the way emitter materials are designed are needed to address this problem. Conventional approaches have only focused on color tuning; however, multi-functional emitter materials are needed to assist the transport of charge in the emissive layer. We propose to design and synthesize new organometallic iridium phosphorescent materials with bipolar charge transport properties to be used in high energy OLEDs and white light configurations

  6. A SYSTEMATIC STUDY ON THE SURFACE CHARGE OF MICROORGANISMS IN DRINKING WATER

    EPA Science Inventory

    The removal of microbiological pathogens from drinking water is an important function of water treatment. The mechanisms of particle and pathogen removal during coagulation/flocculation/filtration processes are well known. Surface charge is particularly important in particle dest...

  7. Scanning tunneling microscopy studies of charge transport in cadmium selenide/zinc sulfide quantum dots

    NASA Astrophysics Data System (ADS)

    Hummon, Marissa Rachel

    2009-12-01

    This thesis examines charge transport in individual colloidal nanocrystals (quantum dots) using a scanning tunneling microscope. We observe coulomb blockade (CB) at room temperature and extract the charging energy of the quantum dot (QD). We analyze time-dependent CB measurements to determine the lifetime and energy of the trapped charge on the QD. A model of the lifetime is presented, furthering our analysis of the charge detrapping mechanism. We observe a hysteresis in the current-voltage (IV) tunneling spectra as the substrate bias is swept from empty to filled states and then back to empty states. This hysteresis is consistent with trapped charge(s) presenting an additional potential barrier to tunneling, a measure of CB. Traditional CB experiments measure a coulomb repulsion due to charge build-up on the island between two electrodes. We observe CB, hysteresis in successive IV sweeps, due to charge trapping/detrapping in a state other than the transport level. This trap state may be related to the dark state in blinking experiments. Optical and electrical measurements of QD trap states are often related to a puzzling physical phenomena observed universally in QDs: blinking. Blinking is the stochastic photoluminescence behavior of quantum dots, where, under constant excitation by a laser, a QD does not emit a continuous stream of photons. In fact, the QD will blink "on" and "off" for completely unpredictable durations that are thought to be related to the QD being in either a neutral or charged state. We measure a lifetime for the charged state of 15 +/- 7 s when Vsub ≤ 1.5 V and 170 +/- 140 ms when Vsub ≥ 1.6 V. The abrupt transition in lifetime between 1.5 and 1.6 V implies that this is the voltage necessary to lower the Au Fermi level equal to the trap state energy, thus allowing the trapped charge to tunnel out of the trap state. The voltage drop between the QD and substrate, determined from a self-consistent calculation of the relative capacitance

  8. Experimental Studies of Ignition Phenomena in One-Dimensional Propelling Charges

    DTIC Science & Technology

    1981-04-01

    by block number) Interior Ballistics Flamespreading Pressure Waves Computer Codes Model Validation 20. ABSTRACT rCotrttmum «a rmwmrmm mtäm...ling Charge. Data recorded during these tests included flame propagation, breech and sidewall gas pressure profiles, and sidewall case strains...Propelling Charge 9 2. Pressure -Time and Pressure -Difference Profiles - Ideal 9 3. Pressure -Time and Pressure -Difference Profiles, 175-mm

  9. A scaled experiment to study energy dissipation process during longitudinal compression of charged particle beams

    NASA Astrophysics Data System (ADS)

    Sakai, Y.; Nakajima, M.; Hasegawa, J.; Kikuchi, T.; Horioka, K.

    2016-03-01

    Beam behavior during longitudinal bunch compression of charged particles was investigated using a compact simulator device based on electron beams. Beam current waveforms and bunch compression ratios were measured as a function of the initial beam current. We found that the current waveform became blunt and the compression ratio degraded at higher beam currents. These results indicate that space-charge fields dissipate the kinetic energy of beam particles.

  10. High-resolution Studies of Charge Exchange in Supernova Remnants with Magellan, XMM-Newton, and Micro-X

    NASA Astrophysics Data System (ADS)

    Heine, Sarah N.; Figueroa-Feliciano, Enectali; Castro, Daniel

    2015-01-01

    Charge exchange, the semi-resonant transfer of an electron from a neutral atom to an excited state in an energetic ion, can occur in plasmas where energetic ions are incident on a cold, at least partially neutral gas. Supernova remnants, especially in the immediate shock region, provide conditions conducive to charge exchange. The emission from post charge-exchange ions as the captured electron cascades down to the ground state, can shed light on the physical conditions of the shock and the immediate post-shock material, providing an important tool to understanding supernova explosions and their aftermath.I present a study of charge exchange in the galactic supernova remnant G296.1-0.5 in two bands: the optical and the X-ray. The optical study, performed using both imaging and spectroscopy from the IMACS instrument on the Magellan Baade Telescope at Las Companas Observatory, seeks to identify `Balmer-dominated shocks' in the remnant, which occur when charge exchange occurs between hot, post-shock protons and colder neutral hydrogen in the environment. The X-ray study probes line ratios in dispersed spectral data obtained with XMM-Newton RGS from an X-ray lobe in the NW of the remnant to hunt for signatures of charge exchange. The dispersed data are degraded by the extended nature of the source, blending many of the lines.We are working towards the future of spectroscopic studies in the X-ray for such extended sources with Micro-X: a sounding rocket-borne, high energy resolution X-ray telescope, utilizing an array of microcalorimeters to achieve high energy resolution for extended sources. I describe the design and commissioning of the payload and the steps toward launch, which is anticipated in the summer of 2015.

  11. Dynamic Charge Storage in Ionic Liquids-Filled Nanopores: Insight from a Computational Cyclic Voltammetry Study.

    PubMed

    He, Yadong; Huang, Jingsong; Sumpter, Bobby G; Kornyshev, Alexei A; Qiao, Rui

    2015-01-02

    Understanding the dynamic charge storage in nanoporous electrodes with room-temperature ionic liquid electrolytes is essential for optimizing them to achieve supercapacitors with high energy and power densities. Herein, we report coarse-grained molecular dynamics simulations of the cyclic voltammetry of supercapacitors featuring subnanometer pores and model ionic liquids. We show that the cyclic charging and discharging of nanopores are governed by the interplay between the external field-driven ion transport and the sloshing dynamics of ions inside of the pore. The ion occupancy along the pore length depends strongly on the scan rate and varies cyclically during charging/discharging. Unlike that at equilibrium conditions or low scan rates, charge storage at high scan rates is dominated by counterions while the contribution by co-ions is marginal or negative. These observations help explain the perm-selective charge storage observed experimentally. We clarify the mechanisms underlying these dynamic phenomena and quantify their effects on the efficiency of the dynamic charge storage in nanopores.

  12. Computational and experimental study of charge distribution in the α-disulfonyl carbanions

    NASA Astrophysics Data System (ADS)

    Binkowska, Iwona; Koput, Jacek; Jarczewski, Arnold

    2014-03-01

    The electron densities of the disulfonyl carbanions were determined using experimental 13C chemical shifts. The 13C NMR spectra and electron densities for the disulfonyl, nitro, and cyano carbon acids were calculated at the MP2/cc-pVDZ level of theory. The calculated chemical shifts for disulfonyl carbanions show satisfying correlation with our own experimental data. The calculated π electron densities at the Cα atom correspond roughly to the "experimental" π electron densities estimated from the 13C chemical shifts. The natural charges at Cα in disulfonyl stabilized carbanions are significantly more negative than with other types of carbanions, partly because of the significant negative natural charge of the α carbon in parent carbon acids. The calculated increase of the negative charge caused by ionization is larger for sulfonyl carbon acids than for cyano- and nitroalkanes. The 13C chemical shifts δ of Cα in disulfonyl stabilized carbanions decrease with more negative calculated negative natural charge at Cα, with a slope of 220 ppm/electron. The influence of phenyl ring para-substitution on the charge distribution in carbanions and relationship between the 13C chemical shifts and charge density have been discussed. It appears that the π electron density in these planar or nearly planar carbanions has a decisive impact on the chemical shifts.

  13. Proton transfer to charged platinum electrodes. A molecular dynamics trajectory study.

    PubMed

    Wilhelm, Florian; Schmickler, Wolfgang; Spohr, Eckhard

    2010-05-05

    A recently developed empirical valence bond (EVB) model for proton transfer on Pt(111) electrodes (Wilhelm et al 2008 J. Phys. Chem. C 112 10814) has been applied in molecular dynamics (MD) simulations of a water film in contact with a charged Pt surface. A total of seven negative surface charge densities σ between -7.5 and -18.9 µC cm(-2) were investigated. For each value of σ, between 30 and 84 initial conditions of a solvated proton within a water slab were sampled, and the trajectories were integrated until discharge of a proton occurred on the charged surfaces. We have calculated the mean rates for discharge and for adsorption of solvated protons within the adsorbed water layer in contact with the metal electrode as a function of surface charge density. For the less negative values of σ we observe a Tafel-like exponential increase of discharge rate with decreasing σ. At the more negative values this exponential increase levels off and the discharge process is apparently transport limited. Mechanistically, the Tafel regime corresponds to a stepwise proton transfer: first, a proton is transferred from the bulk into the contact water layer, which is followed by transfer of a proton to the charged surface and concomitant discharge. At the more negative surface charge densities the proton transfer into the contact water layer and the transfer of another proton to the surface and its discharge occur almost simultaneously.

  14. Bradley's Benzedrine studies on children with behavioral disorders.

    PubMed

    Strohl, Madeleine P

    2011-03-01

    In 1937, psychiatrist Charles Bradley administered Benzedrine sulfate, an amphetamine, to "problem" children at the Emma Pendleton Bradley Home in Providence, Rhode Island, in an attempt to alleviate headaches; however, Bradley noticed an unexpected effect upon the behavior of the children: improved school performance, social interactions, and emotional responses. Drawing on Bradley's published articles on his experiments, this paper explores the historical context of his experiments and the effect this background had on the emerging field of child psychiatry. Bradley's studies went largely ignored in the field of child psychiatry for nearly 25 years. However, they proved to be an important precursor to studies of amphetamines like Ritalin and their use in conditions such as attention deficit hyperactivity disorder. Bradley's Benzedrine trials were thus highly influential in shaping modern objective understandings of children with behavior disorders.

  15. Studies of charged particle beam dynamics on the Paul Trap Simulator Experiment pure ion plasma

    NASA Astrophysics Data System (ADS)

    Chung, Moses

    Based on the compelling physics analogy between intense beam propagating through a periodic focusing quadrupole magnetic field and nonneutral pure ion plasma confined in a linear Paul trap configuration, experimental studies of intense beam propagation under the influence of self-field effects have been performed using the Paul Trap Simulator Experiment (PTSX) device. A new charge collector diagnostic has been implemented, which permits detailed measurement of the radial ion density profile that can be compared with theoretical predictions. To further investigate the trapped plasma properties, a laser-induced fluorescence (LIF) diagnostic system with accompanying barium ion source has also been developed and tested. To achieve a well-characterized initial beam state for subsequent beam physics experiments, ion injection into the trap has been carefully optimized by characterizing various beam dynamics issues that may invalidate the physics analogy between intense coasting beam and trapped pure ion plasma in the quadrupole focusing fields. An optimized plasma is held in the quasi-equilibrium state for more than 50 ms, which is equivalent to more than 3000 full alternating-gradient (AG) focusing periods, and has a defocusing space-charge force that is about 10% of the applied transverse focusing force. The PTSX device is used to investigate basic physics of transverse beam compression. From a comparison of the analytical estimates based on a Kapchinskij-Vladimirskij (KV) beam model, experimental results on changes in both the lattice amplitude and frequency, and particle-in-cell (PIC) simulations, it is found that a key physics issue in transverse beam compression is how to suppress the excitation of mismatch oscillations, which is often accompanied by emittance growth and halo formation. When the phase advance is low enough, adiabatic changes in the smooth-focusing frequency turn out to provide an effective control of transverse beam compression. Machine

  16. Fundamental studies of interfacial excited-state charge transfer in molecularly tethered semiconductor nanoassemblies

    NASA Astrophysics Data System (ADS)

    Youker, Diane Greer

    The research presented in this dissertation focuses on elucidating the parameters affecting dynamics and yield of electron transfer reactions in semiconducting nanoparticle assemblies through the use of time-resolved spectroscopy. In particular, the dissertation focuses on photoinduced electron injection in assemblies of CdSe, CdS, or PbS quantum dots covalently bound to either metal oxide films or each other through the use of bifunctional molecular linkers. Chapter 2 elucidates the influence of electronic coupling on excited-state electron transfer from CdS quantum dots to TiO2 nanoparticles via molecular linkers with phenylene bridges. We establish that the efficiency of electron injection from CdS quantum dots to TiO2 nanoparticle varies dramatically with electronic coupling, which can be controlled by tuning the properties of molecular linkers. Chapter 3 presents the role of excitation energy on interfacial electron transfer in tethered assemblies of CdSe quantum dots and TiO2 nanoparticles. Through this work, we determined that injection efficiency from band-edge states is independent of excitation energy. However, the efficiency of injection from trap-states decreases at lower-energy excitation. We attribute the decrease to a lower energy distribution of emissive trap-states from which injection is less efficient. Chapter 4 presents the observation of multiphasic electron injection dynamics from photoexcited PbS quantum dots to TiO2 nanoparticles. In this collaborative study with Dr. Masumoto from the University of Tsukuba we observed electron injection on multiple timescales. We determined that electron injection occurred in this system through two different mechanisms. The first involved injection from thermalized PbS excited states and the second through injection of hot electrons through Auger recombination of biexcitons that creates high lying excitonic states. Chapter 5 investigates charge transfer in covalently bound quantum dot assemblies. We utilize

  17. The Challenge and Challenging of Childhood Studies? Learning from Disability Studies and Research with Disabled Children

    ERIC Educational Resources Information Center

    Tisdall, E. Kay M.

    2012-01-01

    Childhood studies have argued for the social construction of childhood, respecting children and childhood in the present, and recognising children's agency and rights. Such perspectives have parallels to, and challenges for, disability studies. This article considers such parallels and challenges, leading to a (re)consideration of research claims…

  18. Mean-field and density-functional studies of charge ordering and magnetic transitions in lanthanum manganites

    NASA Astrophysics Data System (ADS)

    Mishra, Snigdharaj Kumar

    Manganese oxides with perovskite structure exhibit many interesting properties. Recently colossal magnetoresistance (CMR) was observed in these oxides. They show extremely large change in electrical resistance in response to applied magnetic fields. This property has lots of technological relevance for the development of magnetic memory and switching devices. These oxides also show transitions from antiferromagnet to ferromagnet coupled with charge-order to charge-nonorder transition. In this dissertation we examine the electronic origin of these phenomena of lanthanum manganites by studying a model electronic Hamiltonian, which includes double-exchange, super-exchange, and Hubbard terms, using a combination of Hartree-Fock approximation and an exact diagonalization scheme. The existence of "canted" spin order is investigated at zero temperature. We find that the double-exchange mechanism does not always lead to a canted magnetic state, even for small carrier concentration. The canting may be suppressed in these compounds for the typical electronic parameters. We study the charge ordering and magnetic transitions in the perovskites by solving the Hamiltonian both at zero and finite temperature. At zero temperature as we increase the strength of the extended-Hubbard repulsion (Usb1), a first-order transition from a charge-non-ordered metallic ferromagnet (FN) to a charge-ordered, insulating antiferromagnet (AFO) is obtained. The AFO-FN transition is also obtained by increasing the temperature T. The melting of charge ordering as a function of temperature, doping concentration and magnetic field is also examined. Different phases are obtained as a function of temperature and doping concentration. These are in qualitative agreement with experimental data. We study the electronic structures of pyrochlores by the density-functional LMTO method and show that the double-exchange mechanism is relevant for these compounds as well.

  19. Charge separation and transport in conjugated-polymer/semiconductor-nanocrystal composites studied by photoluminescence quenching and photoconductivity

    SciTech Connect

    Greenham, N.C.; Peng, X.; Alivisatos, A.P.

    1996-12-01

    We study the processes of charge separation and transport in composite materials formed by mixing cadmium selenide or cadmium sulfide nanocrystals with the conjugated polymer poly(2-methoxy,5-(2{prime}-ethyl)-hexyloxy-{ital p}-phenylenevinylene) (MEH-PPV). When the surface of the nanocrystals is treated so as to remove the surface ligand, we find that the polymer photoluminescence is quenched, consistent with rapid charge separation at the polymer/nanocrystal interface. Transmission electron microscopy of these quantum-dot/conjugated-polymer composites shows clear evidence for phase segregation with length scales in the range 10{endash}200 nm, providing a large area of interface for charge separation to occur. Thin-film photovoltaic devices using the composite materials show quantum efficiencies that are significantly improved over those for pure polymer devices, consistent with improved charge separation. At high concentrations of nanocrystals, where both the nanocrystal and polymer components provide continuous pathways to the electrodes, we find quantum efficiencies of up to 12{percent}. We describe a simple model to explain the recombination in these devices, and show how the absorption, charge separation, and transport properties of the composites can be controlled by changing the size, material, and surface ligands of the nanocrystals. {copyright} {ital 1996 The American Physical Society.}

  20. Molecular orbital studies of enzyme activity: I: Charge relay system and tetrahedral intermediate in acylation of serine proteinases.

    PubMed Central

    Scheiner, S; Kleier, D A; Lipscomb, W N

    1975-01-01

    The charge relay ststem and its role in the acylation of serine proteinases is studied using the partial retention of diatomic differential overlap (PRDDO) technique to perform approximate ab initio molecular orbital calculations on a model of the enzyme-substrate complex. The aspartate in the charge relay system is seen to act as the ultimate proton acceptor during the charging of the serine nucleophile. A projection of the potential energy surface is obtained in a subspace corresponding to this charge transfer and to the coupled motions of active site residues and the substrate. These results together with extended basis set results for cruder models suggest that a concerted transfer of protons from Ser-195 to His-57 and from His-57 to Asp-102 occurs with an energy barrier of 20-25 kcal/mole (84-105 kJ/mole). The subsequent nucleophilic attack on the scissile peptide linkage by the charged serine is then seen to proceed energetically downhill to the tetrahedral intermediate. The formation of the tetrahedral intermediate from the Michaelis complex is calculated to be nearly thermoneutral. PMID:1058476

  1. X-ray absorption structural study of a reversible, photoexcited charge-transfer state

    SciTech Connect

    Chen, L.X.; Bowman, M.K.; Norris, J.R. Univ. of Chicago, IL ); Montano, P.A. )

    1993-05-19

    Electron-transfer reactions can be accompanied by significant nuclear movements. Nuclear motion appears to be especially vital to the reversible, photoinduced charge-transfer chemistry of cyclopentadienylnickel nitrosyl (C[sub 5]H[sub 5]NiNO). Although extended X-ray absorption fine structure (EXAFS) spectroscopy has recorded photoinduced changes in the ligation of myoglobins, similar X-ray studies of electron-transfer chemistry have not been reported. Here we examine reversible, photoinduced structural changes in C[sub 5]H[sub 5]NiNO by EXAFS and propose a mechanism for the electron-transfer chemistry. This work demonstrates that EXAFS can measure distance changes accompanying photoinduced electron transfer to provide new details of the geometry of photoexcited state and suggests that electron transfer occurs in the transient, optically excited states of C[sub 5]H[sub 5]NiNO and C[sub 5]H[sub 5]NiNO[sup CT] as dictated by NO movement that produces either C[sub 5]H[sub 5]NiNO[sup CT] or C[sub 5]H[sub 5]NiNO[sup GS]. 14 refs., 2 figs.

  2. Unveiling the nucleon tensor charge at Jefferson Lab: A study of the SoLID case

    NASA Astrophysics Data System (ADS)

    Ye, Zhihong; Sato, Nobuo; Allada, Kalyan; Liu, Tianbo; Chen, Jian-Ping; Gao, Haiyan; Kang, Zhong-Bo; Prokudin, Alexei; Sun, Peng; Yuan, Feng

    2017-04-01

    Future experiments at the Jefferson Lab 12 GeV upgrade, in particular, the Solenoidal Large Intensity Device (SoLID), aim at a very precise data set in the region where the partonic structure of the nucleon is dominated by the valence quarks. One of the main goals is to constrain the quark transversity distributions. We apply recent theoretical advances of the global QCD extraction of the transversity distributions to study the impact of future experimental data from the SoLID experiments. Especially, we develop a simple strategy based on the Hessian matrix analysis that allows one to estimate the uncertainties of the transversity quark distributions and their tensor charges extracted from SoLID data simulation. We find that the SoLID measurements with the proton and the effective neutron targets can improve the precision of the u- and d-quark transversity distributions up to one order of magnitude in the range 0.05 < x < 0.6.

  3. Theoretical study of neutral and charged Sc n≤2-(benzene) m≤3 clusters

    NASA Astrophysics Data System (ADS)

    Maynez-Rojas, Miguel; Castro, Miguel

    2013-01-01

    Interactions of benzene molecules with scandium atoms, Sc n≤2-(C6H6) m≤3, in the gas phase were studied by means of density functional theory. All-electron calculations were performed using the B3LYP hybrid functional in concert with 6-311+G(d,p) orbital basis sets for the Sc, C, and H atoms. Multiple-decker sandwich (MDS) structures are identified as the ground states for Sc n≤2-(C6H6) m≤3, where the ligands are attached to the metal through Sc-C bonding, formed between the 3d electrons and the π-clouds of the benzene rings. Significant distortion is produced on the absorbed benzene molecules by the metal-ligand bonding. Rice ball structures also appeared, but they were found at higher energies, in such a way that essentially MDS isomers may emerge in the molecular beams. Even the low number of valence electrons (3d24s1) of the Sc atom; sextuple coordinations are formed, but they show different Sc-C bond lengths, diminishing the symmetry of neutral and charged clusters. The estimated ionization energies, in near agreement with experimental data, and electron affinities, suggest delocalization of the valence electrons through the network of 3d-π bonds of Sc1,2-(C6H6) m≤3. The binding energies decrease with the absorption of more benzene molecules, and in some cases increase as more metal atoms are added to the cluster.

  4. Background Rejection of Charged Particles in the Simbol-X Telescope: Preliminary Study of Protons Scattering

    NASA Astrophysics Data System (ADS)

    Dell'Orto, E.; Barbera, M.; Bulgarelli, A.; Fioretti, V.; Malaguti, G.; Mineo, T.; Pareschi, G.; Rigato, V.; Spiga, D.; Tagliaferri, G.

    2009-05-01

    X-ray telescopes equipped with focusing optics in high eccentric orbit, as e.g. Newton-XMM and Chandra, showed a degradation of the detector performance and an important increase of the noise due to soft protons with energy between a few tens of keV and a few MeV, that are focused on the detector through the mirror module. It should be noted that the focusing of the protons by Wolter optics was an unexpected phenomenon. In Simbol-X a magnetic diverter will be implemented to deflect protons, in order to reduce the flux of charged particles impinging upon the focal plane. Obviously the design of the diverter should take into consideration the protons distribution at the exit of the mirror module; for this reason a detailed simulation about the interaction of particles with the mirror surface is necessary. Here we will present the scattering protons models currently under consideration, suggesting a preliminary solution for the design of the magnetic diverter. We will also discuss an ad hoc experiment to study this problem.

  5. Background Rejection of Charged Particles in the Simbol-X Telescope: Preliminary Study of Protons Scattering

    SciTech Connect

    Dell'Orto, E.; Barbera, M.; Bulgarelli, A.; Fioretti, V.; Malaguti, G.; Mineo, T.; Pareschi, G.; Spiga, D.; Tagliaferri, G.; Rigato, V.

    2009-05-11

    X-ray telescopes equipped with focusing optics in high eccentric orbit, as e.g. Newton-XMM and Chandra, showed a degradation of the detector performance and an important increase of the noise due to soft protons with energy between a few tens of keV and a few MeV, that are focused on the detector through the mirror module. It should be noted that the focusing of the protons by Wolter optics was an unexpected phenomenon. In Simbol-X a magnetic diverter will be implemented to deflect protons, in order to reduce the flux of charged particles impinging upon the focal plane. Obviously the design of the diverter should take into consideration the protons distribution at the exit of the mirror module; for this reason a detailed simulation about the interaction of particles with the mirror surface is necessary. Here we will present the scattering protons models currently under consideration, suggesting a preliminary solution for the design of the magnetic diverter. We will also discuss an ad hoc experiment to study this problem.

  6. Environmentally Reformed Travel Habits During the 2006 Congestion Charge Trial in Stockholm—A Qualitative Study

    PubMed Central

    Henriksson, Greger; Hagman, Olle; Andréasson, Håkan

    2011-01-01

    Policy measures that reduce or replace road traffic can improve environmental conditions in most large cities. In Stockholm a congestion charge was introduced during a test period in 2006. This was a full-scale trial that proved to meet its targets by reducing traffic crossing the inner city segment during rush hours by 20%. Emissions of carbon dioxide and particles were also substantially reduced. This study, based on in-depth interviews with 40 inhabitants, analyses how and why new travel habits emerged. The results show that particular, sometimes unexpected, features of everyday life (habits, resources, opportunities, values, etc.) were crucial for adjustment of travel behaviour in relation to the policy instrument. One example was that those accustomed to mixing different modes of transport on a daily basis more easily adapted their travel in the targeted way. On a more general level, the results revealed that the policy measure could actually tip the scales for the individual towards trying out a new behaviour. PMID:21909301

  7. Numerical study of an electrostatic plasma sheath containing two species of charged dust particles

    SciTech Connect

    Foroutan, G.; Akhoundi, A.

    2012-10-01

    A multi-fluid model is used to study the dynamics of a dusty plasma sheath consists of electrons, ions, and two species of charged dust particles, i.e., nano-size and micron-size particles. It is found that, when the sheath is dominated by the nano-size dust grains, spatially periodic fluctuations are developed in the profiles of the sheath potential, and the number density and velocity of the plasma and dust particles. Due to inertial effects, the fluctuations in the parameters of the micron-size grains are much lower than those of the other parameters. The competition between the electric and ion drag forces plays the primary role in development of the fluctuations. The spatial period of the fluctuations is approximately a few Debye lengths and their amplitude depends on the plasma and dust parameters. The fluctuations are reduced by the increase in the radius, mass density, and Mach number of the nano-size particles, as well as the density and Mach number of the ions. But, they are enhanced by the increase in the plasma number density and the electron temperature. The sheath thickness demonstrates a non-monotonic behavior against variation of the nanoparticle parameters, i.e., it first decreases quickly, shows a minimum, and then increases. However, the sheath width always decreases with the plasma number density and ion Mach number, while grows linearly with the electron temperature.

  8. Environmentally reformed travel habits during the 2006 congestion charge trial in Stockholm--a qualitative study.

    PubMed

    Henriksson, Greger; Hagman, Olle; Andréasson, Håkan

    2011-08-01

    Policy measures that reduce or replace road traffic can improve environmental conditions in most large cities. In Stockholm a congestion charge was introduced during a test period in 2006. This was a full-scale trial that proved to meet its targets by reducing traffic crossing the inner city segment during rush hours by 20%. Emissions of carbon dioxide and particles were also substantially reduced. This study, based on in-depth interviews with 40 inhabitants, analyses how and why new travel habits emerged. The results show that particular, sometimes unexpected, features of everyday life (habits, resources, opportunities, values, etc.) were crucial for adjustment of travel behaviour in relation to the policy instrument. One example was that those accustomed to mixing different modes of transport on a daily basis more easily adapted their travel in the targeted way. On a more general level, the results revealed that the policy measure could actually tip the scales for the individual towards trying out a new behaviour.

  9. Numerical study of the gravitational shock wave inside a spherical charged black hole

    NASA Astrophysics Data System (ADS)

    Eilon, Ehud; Ori, Amos

    2016-11-01

    We numerically investigate the interior of a four-dimensional, asymptotically flat, spherically symmetric charged black hole perturbed by a scalar field Φ . Previous study by Marolf and Ori indicated that late infalling observers will encounter an effective shock wave as they approach the left portion of the inner horizon. This shock manifests itself as a sudden change in the values of various fields, within a tremendously short interval of proper time τ of the infalling observers. We confirm this prediction numerically for both test and self-gravitating scalar-field perturbations. In both cases we demonstrate the effective shock in the scalar field by exploring Φ (τ ) along a family of infalling timelike geodesics. In the self-gravitating case we also demonstrate the shock in the area coordinate r by exploring r (τ ). We confirm the theoretical prediction concerning the shock sharpening rate, which is exponential in the time of infall into the black hole. In addition we numerically probe the early stages of shock formation. We also employ a family of null (rather than timelike) ingoing geodesics to probe the shock in r . We use a finite-difference numerical code with double-null coordinates combined with a recently developed adaptive gauge method in order to solve the (Einstein+scalar ) field equations and to evolve the spacetime (and scalar field)—from the region outside the black hole down to the vicinity of the Cauchy horizon and the spacelike r =0 singularity.

  10. Hydration of the cyanide ion: an ab initio quantum mechanical charge field molecular dynamics study.

    PubMed

    Moin, Syed Tarique; Hofer, Thomas S

    2014-12-21

    This paper presents an ab initio quantum mechanical charge field molecular dynamics simulation study of the cyanide anion (CN(-)) in aqueous solution where hydrogen bond formation plays a dominant role in the hydration process. Preferential orientation of water hydrogens compared to oxygen atoms was quantified in terms of radial, angular as well as coordination number distributions. All structural results indicate that the water hydrogens are attracted towards CN(-) atoms, thus contributing to the formation of the hydration layer. Moreover, a clear picture of the local arrangement of water molecules around the ellipsoidal CN(-) ion is provided via angular-radial distribution and spatial distribution functions. Apart from the structural analysis, the evaluation of water dynamics in terms of ligand mean residence times and H-bond correlation functions indicates the weak structure making capacity of the CN(-) ion. The similar values of H-bond lifetimes obtained for the NHwat and CHwat bonds indicate an isokinetic behaviour of these H-bonds, since there is a very small difference in the magnitude of the lifetimes. On the other hand, the H-bond lifetimes between water molecules of the hydration shell, and between solute and solvent evidence the slightly stable hydration of the CN(-). Overall, the H-bonding dominates in the hydration process of the cyanide anion enabling it to become soluble in the aqueous environment associated to chemical and biological processes.

  11. Children's Experiences and Meaning Construction on Parental Divorce: A Focus Group Study

    ERIC Educational Resources Information Center

    Maes, Sofie D. J.; De Mol, Jan; Buysse, Ann

    2012-01-01

    The global aim of this study was to explore children's narratives of parental divorce. A convenience sample, composed of 11- and 14-year-old children, was recruited. A total of 22 children (12 male, 10 female) participated in this focus group study. The findings show that two components seem to be really important for children during the divorce…

  12. A Population-Based Longitudinal Study of Depression in Children with Developmental Disabilities in Manitoba

    ERIC Educational Resources Information Center

    Shooshtari, Shahin; Brownell, Marni; Dik, Natalia; Chateau, Dan; Yu, C. T.; Mills, Rosemary S. L.; Burchill, Charles A.; Wetzel, Monika

    2014-01-01

    In this population-based study, prevalence of depression was estimated and compared between children with and without developmental disability (DD). Twelve years of administrative data were linked to identify a cohort of children with DD living in the Canadian province of Manitoba. Children in the study cohort were matched with children without DD…

  13. A Study of the Communicative Abilities of Disadvantaged Children. Final Report.

    ERIC Educational Resources Information Center

    Osser, Harry; And Others

    The purpose of this series of four studies was to precisely describe the code and dialect features of the speech of both lower class Negro children and middle class white children. In the first study, 16 white middle class (WMC) children were compared to 16 Negro lower class (NLC) children on both an imitation and a comprehension task. The WMC…

  14. Theoretical and experimental study of the space-charge oscillations in the electron-optical system of a relativistic gyrotron

    SciTech Connect

    Ilyakov, E. V. Kulagin, I. S.; Manuilov, V. N.; Movshevich, B. Z.

    2011-12-15

    A theoretical and experimental study of the oscillations of a space-charge cloud in a magnetron-injection gun of a powerful relativistic gyrotron has been performed. The charge storage occurs via electron-beam magnetic compression of the reflection of a part of the electrons having the highest transverse velocities from a magnetic mirror. It has been established that at high values of the compression coefficient the beam loses its stability that finally leads to the appearance of the beam current modulation at the frequency of the longitudinal oscillations of an electron beam in an adiabatic trap. According to the numerical simulations, the energy spread in the formed beam under these conditions reaches 4.6%, which is higher by an order of magnitude than that due to the space-charge effect in the beam transported along the metal tube.

  15. A relativistic self-consistent model for studying enhancement of space charge limited emission due to counter-streaming ions

    NASA Astrophysics Data System (ADS)

    Lin, M. C.; Verboncoeur, J.

    2016-10-01

    A maximum electron current transmitted through a planar diode gap is limited by space charge of electrons dwelling across the gap region, the so called space charge limited (SCL) emission. By introducing a counter-streaming ion flow to neutralize the electron charge density, the SCL emission can be dramatically raised, so electron current transmission gets enhanced. In this work, we have developed a relativistic self-consistent model for studying the enhancement of maximum transmission by a counter-streaming ion current. The maximum enhancement is found when the ion effect is saturated, as shown analytically. The solutions in non-relativistic, intermediate, and ultra-relativistic regimes are obtained and verified with 1-D particle-in-cell simulations. This self-consistent model is general and can also serve as a comparison for verification of simulation codes, as well as extension to higher dimensions.

  16. Systems Based Study of the Therapeutic Potential of Small Charged Molecules for the Inhibition of IL-1 Mediated Cartilage Degradation

    PubMed Central

    Kar, Saptarshi; Smith, David W.; Gardiner, Bruce S.; Grodzinsky, Alan J.

    2016-01-01

    Inflammatory cytokines are key drivers of cartilage degradation in post-traumatic osteoarthritis. Cartilage degradation mediated by these inflammatory cytokines has been extensively investigated using in vitro experimental systems. Based on one such study, we have developed a computational model to quantitatively assess the impact of charged small molecules intended to inhibit IL-1 mediated cartilage degradation. We primarily focus on the simplest possible computational model of small molecular interaction with the IL-1 system—direct binding of the small molecule to the active site on the IL-1 molecule itself. We first use the model to explore the uptake and release kinetics of the small molecule inhibitor by cartilage tissue. Our results show that negatively charged small molecules are excluded from the negatively charged cartilage tissue and have uptake kinetics in the order of hours. In contrast, the positively charged small molecules are drawn into the cartilage with uptake and release timescales ranging from hours to days. Using our calibrated computational model, we subsequently explore the effect of small molecule charge and binding constant on the rate of cartilage degradation. The results from this analysis indicate that the small molecules are most effective in inhibiting cartilage degradation if they are either positively charged and/or bind strongly to IL-1α, or both. Furthermore, our results showed that the cartilage structural homeostasis can be restored by the small molecule if administered within six days following initial tissue exposure to IL-1α. We finally extended the scope of the computational model by simulating the competitive inhibition of cartilage degradation by the small molecule. Results from this model show that small molecules are more efficient in inhibiting cartilage degradation by binding directly to IL-1α rather than binding to IL-1α receptors. The results from this study can be used as a template for the design and

  17. A molecular dynamics study on the transport of a charged biomolecule in a polymeric adsorbent medium and its adsorption onto a charged ligand

    NASA Astrophysics Data System (ADS)

    Riccardi, E.; Wang, J.-C.; Liapis, A. I.

    2010-08-01

    The transport of a charged adsorbate biomolecule in a porous polymeric adsorbent medium and its adsorption onto the covalently immobilized ligands have been modeled and investigated using molecular dynamics modeling and simulations as the third part of a novel fundamental methodology developed for studying ion-exchange chromatography based bioseparations. To overcome computational challenges, a novel simulation approach is devised where appropriate atomistic and coarse grain models are employed simultaneously and the transport of the adsorbate is characterized through a number of locations representative of the progress of the transport process. The adsorbate biomolecule for the system studied in this work changes shape, orientation, and lateral position in order to proceed toward the site where adsorption occurs and exhibits decreased mass transport coefficients as it approaches closer to the immobilized ligand. Furthermore, because the ligands are surrounded by counterions carrying the same type of charge as the adsorbate biomolecule, it takes the biomolecule repeated attempts to approach toward a ligand in order to displace the counterions in the proximity of the ligand and to finally become adsorbed. The formed adsorbate-ligand complex interacts with the counterions and polymeric molecules and is found to evolve slowly and continuously from one-site (monovalent) interaction to multisite (multivalent) interactions. Such a transition of the nature of adsorption reduces the overall adsorption capacity of the ligands in the adsorbent medium and results in a type of surface exclusion effect. Also, the adsorption of the biomolecule also presents certain volume exclusion effects by not only directly reducing the pore volume and the availability of the ligands in the adjacent regions, but also causing the polymeric molecules to change to more compact structures that could further shield certain ligands from being accessible to subsequent adsorbate molecules. These

  18. A molecular dynamics study on the transport of a charged biomolecule in a polymeric adsorbent medium and its adsorption onto a charged ligand.

    PubMed

    Riccardi, E; Wang, J-C; Liapis, A I

    2010-08-28

    The transport of a charged adsorbate biomolecule in a porous polymeric adsorbent medium and its adsorption onto the covalently immobilized ligands have been modeled and investigated using molecular dynamics modeling and simulations as the third part of a novel fundamental methodology developed for studying ion-exchange chromatography based bioseparations. To overcome computational challenges, a novel simulation approach is devised where appropriate atomistic and coarse grain models are employed simultaneously and the transport of the adsorbate is characterized through a number of locations representative of the progress of the transport process. The adsorbate biomolecule for the system studied in this work changes shape, orientation, and lateral position in order to proceed toward the site where adsorption occurs and exhibits decreased mass transport coefficients as it approaches closer to the immobilized ligand. Furthermore, because the ligands are surrounded by counterions carrying the same type of charge as the adsorbate biomolecule, it takes the biomolecule repeated attempts to approach toward a ligand in order to displace the counterions in the proximity of the ligand and to finally become adsorbed. The formed adsorbate-ligand complex interacts with the counterions and polymeric molecules and is found to evolve slowly and continuously from one-site (monovalent) interaction to multisite (multivalent) interactions. Such a transition of the nature of adsorption reduces the overall adsorption capacity of the ligands in the adsorbent medium and results in a type of surface exclusion effect. Also, the adsorption of the biomolecule also presents certain volume exclusion effects by not only directly reducing the pore volume and the availability of the ligands in the adjacent regions, but also causing the polymeric molecules to change to more compact structures that could further shield certain ligands from being accessible to subsequent adsorbate molecules. These

  19. Laboratory Studies of Charging Properties of Dust Grains in Astrophysical/Planetary Environments

    NASA Technical Reports Server (NTRS)

    Tankosic, D.; Abbas, M. M.

    2012-01-01

    Dust grains in various astrophysical environments are generally charged electrostatically by photoelectric emissions with UV/X-ray radiation, as well as by electron/ion impact. Knowledge of physical and optical properties of individual dust grains is required for understanding of the physical and dynamical processes in space environments and the role of dust in formation of stellar and planetary systems. In this paper we focus on charging of individual micron/submicron dust grains by processes that include: (a) UV photoelectric emissions involving incident photon energies higher than the work function of the material and b) electron impact, where low energy electrons are scattered or stick to the dust grains, thereby charging the dust grains negatively, and at sufficiently high energies the incident electrons penetrate the grain leading to excitation and emission of electrons referred to as secondary electron emission (SEE). It is well accepted that the charging properties of individual micron/submicron size dust grains are expected to be substantially different from the bulk materials. However, no viable models for calculation of the charging properties of individual micron size dust grains are available at the present time. Therefore, the photoelectric yields, and secondary electron emission yields of micron-size dust grains have to be obtained by experimental methods. Currently, very limited experimental data are available for charging of individual micron-size dust grains. Our experimental results, obtained on individual, micron-size dust grains levitated in an electrodynamic balance facility (at NASA-MSFC), show that: (1) The measured photoelectric yields are substantially higher than the bulk values given in the literature and indicate a particle size dependence with larger particles having order-of-magnitude higher values than for submicron-size grains; (2) dust charging by low energy electron impact is a complex process. Also, our measurements indicate that

  20. Impact of updraft on neutralized charge rate by lightning in thunderstorms: A simulation case study

    NASA Astrophysics Data System (ADS)

    Wang, Fei; Zhang, Yijun; Zheng, Dong

    2015-12-01

    The rate of neutralized charge by lightning (RNCL) is an important parameter indicating the intensity of lightning activity. The total charging rate (CR), the CR of one kind of polarity (e.g., negative) charge (CROP), and the outflow rate of charge on precipitation (ORCP) are proposed as key factors impacting RNCL, based on the principle of conservation of one kind of polarity charge in a thunderstorm. In this paper, the impacts of updraft on CR and CROP are analyzed by using a 3D cloud resolution model for a strong storm that occurred in Beijing on 6 september 2008. The results show that updraft both promotes and inhibits RNCL at the same time. (1) Updraft always has a positive influence on CR. The correlation coefficient between the updraft volume and CR can reach 0.96. Strengthening of the updraft facilitates strengthening of RNCL through this positive influence. (2) Strengthening of the updraft also promotes reinforcement of CROP. The correlation coefficient between the updraft volume and CROP is high (about 0.9), but this promotion restrains the strengthening of RNCL because the strengthening of CROP will, most of the time, inhibit the increasing of RNCL. (3) Additionally, increasing of ORCP depresses the strengthening of RNCL. In terms of magnitude, the peak of ORCP is equal to the peak of CR. Because precipitation mainly appears after the lightning activity finishes, the depression effect of ORCP on RNCL can be ignored during the active lightning period.

  1. The interaction between electrolyte and surfaces decorated with charged groups: A molecular dynamics simulation study.

    PubMed

    Calero, Carles; Faraudo, Jordi

    2010-01-14

    In this paper, we perform molecular dynamics simulations of an interface containing charged functional groups of different valences in contact with 2:1 ionic solution. We take into account both the finite sizes of the ions in solution and the functional groups but we neglect the structural details of the solvent (primitive model). We show that the distribution of ions and the electrostatic properties of the system depend strongly on the valence of the interfacial charged groups. In the case of surfaces containing well-separated charged interfacial groups, we observe counterion binding at these groups induced by electrostatic interactions. A detailed analysis of the potential of mean force between interfacial charged groups and ions reveals significant features not anticipated by present theories of electrolytes near interfaces. Overall, our results show that, in primitive models of the ion-interface interaction, not only the ionic size and valence are important but the size and valence of the interfacial charged groups also have a significant impact.

  2. A theoretical model for smoking prevention studies in preteen children.

    PubMed

    McGahee, T W; Kemp, V; Tingen, M

    2000-01-01

    The age of the onset of smoking is on a continual decline, with the prime age of tobacco use initiation being 12-14 years. A weakness of the limited research conducted on smoking prevention programs designed for preteen children (ages 10-12) is a well-defined theoretical basis. A theoretical perspective is needed in order to make a meaningful transition from empirical analysis to application of knowledge. Bandura's Social Cognitive Theory (1977, 1986), the Theory of Reasoned Action (Ajzen & Fishbein, 1980), and other literature linking various concepts to smoking behaviors in preteens were used to develop a model that may be useful for smoking prevention studies in preteen children.

  3. The dominance of small ions in the electric double layer of size- and charge-asymmetric electrolytes: a mean-field study on the charge reversal and surface charge amplification

    NASA Astrophysics Data System (ADS)

    Angélica Barrios-Contreras, Evelyn; González-Tovar, Enrique; Iván Guerrero-García, Guillermo

    2015-05-01

    The dominance of counterions in the electric double layer of size-asymmetric semi-punctual ions was proposed more than 30 years ago by Valleau and Torrie. According to their theoretical prescription, at large colloidal surface charges, the double layer properties of a fully asymmetric binary electrolyte become similar to those of a completely symmetric electrolyte if the properties of counterions are the same in both instances. In the same theoretical framework, we propose here that, for a fixed concentration of the smallest ionic species and weakly/moderate colloidal surface charges, the valence of small ions rules or mainly determines the structural and thermodynamic properties of the electric double layer regardless of the colloidal polarity. In other words, we show that the characteristics of the small ions dominate the double layer structure of non-highly charged colloids, independently if the small ions are coions or counterions. This is illustrated by a comprehensive analysis of the ionic and integrated charge profiles around a spherical macroion immersed in a fully size- and charge-asymmetric semi-punctual electrolyte. Charge reversal and surface charge amplification are observed in the regime of low/medium colloidal surface charge densities. The origin of these counterintuitive phenomena, and their corresponding localisation properties in the Helmholtz zone, are explained in terms of the electric double layer structure.

  4. A Normative Study of Children's Drawings: Preliminary Research Findings

    ERIC Educational Resources Information Center

    Deaver, Sarah P.

    2009-01-01

    This paper describes methodology, data analysis, and initial results of a research study with the long-term goal of establishing contemporary normative data on drawings from children living in the United States. The pool of participants was composed of 316 fourth graders (mean age 9.69 years) and 151 second graders (mean age 7.56 years) who each…

  5. A Longitudinal Study of Selected Characteristics of Children's Melodic Improvisations

    ERIC Educational Resources Information Center

    Brophy, Timothy S.

    2005-01-01

    This study is an examination of the melodic improvisations of a group of children (N = 62) for 3 years, from ages 7 through 9. Participants improvised as part of a class rondo for Orff instruments, in ABACADA form, in which the B, C, and D sections were 8-measure alto-xylophone improvisations in C pentatonic. Each participant improvised three…

  6. Children's Social Learning: Implications of Research and Expert Study.

    ERIC Educational Resources Information Center

    Ambrose, Edna; Miel, Alice

    This book, designed as an aid for teachers and curriculum developers, reports the findings of a study of children's social learnings and the ways they are acquired. Topics covered are: (1) a perspective on social learning--definition of social learnings, a view of social learnings, social learnings for democratic living, social learnings related…

  7. Studying Children in Context: Theories, Methods, and Ethics.

    ERIC Educational Resources Information Center

    Graue, M. Elizabeth; Walsh, Daniel J.; Ceglowski, Deborah; Dyson, Anne Hass; Fernie, David E.; Kantor, Rebecca; Leavitt, Robin Lynn; Miller, Peggy J.; Ting, Hsueh-Yin

    Studying or finding out about children is exceptionally difficult--intellectually, physically, and emotionally. Physical, social, cognitive, and political distances between adult and the child make their relationship very different from the relationships among adults. This book explains the art and science of doing qualitative research involving…

  8. Theory, Method, and Triangulation in the Study of Street Children.

    ERIC Educational Resources Information Center

    Lucchini, Riccardo

    1996-01-01

    Describes how a comparative study of street children in Montevideo (Uruguay), Rio de Janeiro, and Mexico City contributes to a synergism between theory and method. Notes how theoretical approaches of symbolic interactionism, genetic structuralism, and habitus theory complement interview, participant observation, and content analysis methods;…

  9. Understanding Insecure Attachment: A Study Using Children's Bird Nest Imagery

    ERIC Educational Resources Information Center

    Sheller, Sandy

    2007-01-01

    This article describes a phenomenological study of the artistic creations of bird nests by four school-aged children to illuminate their internal experiences of attachment. The author analyzed qualitative data from in-depth interviews pertaining to two-dimensional and three-dimensional artistic representations of a bird's nest and a family of…

  10. RECRUITMENT AND RETENTION ISSUES FOR THE NATIONAL CHILDREN'S STUDY

    EPA Science Inventory

    A better understanding of the most effective recruitment techniques and retention strategies for longitudinal, community-based, children's environmental health studies is needed. A series of 18 focus groups were conducted across the U.S. in February 2003. Pregnant women and exp...

  11. DIETARY EXPOSURES OF YOUNG CHILDREN, PART II: FIELD STUDY

    EPA Science Inventory

    A small, pilot field study was conducted to determine the adequacy of protocols for dietary exposure measurements. Samples were collected to estimate the amount of pesticides transferred from contaminated surfaces or hands to foods of young children and to validate a dietary mod...

  12. IDENTIFYING RECRUITMENT AND RETENTION ISSUES FOR THE NATIONAL CHILDREN'S STUDY

    EPA Science Inventory

    Recruitment and Retention Issues for the National Children's Study
    Danelle T Lobdell1, Suzanne Gilboa2, Pauline Mendola1 (1US EPA, NHEERL; 2UNC Chapel Hill)

    A better understanding of the most effective recruitment techniques and retention strategies for longitudinal, co...

  13. Research updates in neuroimaging studies of children who stutter.

    PubMed

    Chang, Soo-Eun

    2014-05-01

    In the past two decades, neuroimaging investigations of stuttering have led to important discoveries of structural and functional brain differences in people who stutter, providing significant clues to the neurological basis of stuttering. One major limitation, however, has been that most studies so far have only examined adults who stutter, whose brain and behavior likely would have adopted compensatory reactions to their stuttering; these confounding factors have made interpretations of the findings difficult. Developmental stuttering is a neurodevelopmental condition, and like many other neurodevelopmental disorders, stuttering is associated with an early childhood onset of symptoms and greater incidence in males relative to females. More recent studies have begun to examine children who stutter using various neuroimaging techniques that allow examination of functional neuroanatomy and interaction of major brain areas that differentiate children who stutter compared with age-matched controls. In this article, I review these more recent neuroimaging investigations of children who stutter, in the context of what we know about typical brain development, neuroplasticity, and sex differences relevant to speech and language development. Although the picture is still far from complete, these studies have potential to provide information that can be used as early objective markers, or prognostic indicators, for persistent stuttering in the future. Furthermore, these studies are the first steps in finding potential neural targets for novel therapies that may involve modulating neuroplastic growth conducive to developing and maintaining fluent speech, which can be applied to treatment of young children who stutter.

  14. A Study of Otoneurologic and Balance Tests with Deaf Children.

    ERIC Educational Resources Information Center

    Holderbaum, Flora M. Ingalls; And Others

    1979-01-01

    To determine whether or not the Floor Ataxia Test Battery (FATB) is associated with vestibular dysfunction, 31 deaf children (mean age 13 years) were studied. Performance on the FATB and the Heath Railwalking Test were compared to nystagmus reactions induced by the cold water caloric test. (Author/PHR)

  15. Children's Acquisition of Visuo-Spatial Dimensionality: A Conservation Study.

    ERIC Educational Resources Information Center

    Kershner, John R.

    The effects of laterality, movement, and language on children's ability to conserve multiple space relations were investigated in this study of visuo-spatial dimensionality acquisition. The sample for the experiment consisted of 160 first-graders (80 boys, 80 girls) who were matched on intelligence and socioeconomic status. These subjects were…

  16. QUALITY MANAGEMENT PLAN FOR THE NATIONAL CHILDREN'S STUDY

    EPA Science Inventory

    EPA has taken the lead, in consort with NIH, in developing the Quality Management Plan (QMP) for the National Children's Study (NCS); the QMP will delineate a systematic planning process for the implementation of the NCS. The QMP will state the goals and objectives of the NCS, th...

  17. Balancing Voice and Protection in Literacy Studies with Young Children

    ERIC Educational Resources Information Center

    Rogers, Rebecca; Labadie, Meredith; Pole, Kathryn

    2016-01-01

    One of the tensions in conducting participatory literacy research with young children is finding the balance between protection and voice. In this paper, we describe how we sought to create participant-centred research techniques within the evolving design of a yearlong action research study with kindergarten students. Through weekly classroom…

  18. FINAL REPORT: NATIONAL CHILDREN'S STUDY FOCUS GROUPS - FOLLOW-UP

    EPA Science Inventory

    The purpose of this work assignment was to add to our knowledge of the issues that will affect

    recruitment and retention of pregnant women into the National Children's Study by conducting 14 focus

    groups comprised of pregnant women, couples, and parents of young chi...

  19. Speech Sound Disorders in a Community Study of Preschool Children

    ERIC Educational Resources Information Center

    McLeod, Sharynne; Harrison, Linda J.; McAllister, Lindy; McCormack, Jane

    2013-01-01

    Purpose: To undertake a community (nonclinical) study to describe the speech of preschool children who had been identified by parents/teachers as having difficulties "talking and making speech sounds" and compare the speech characteristics of those who had and had not accessed the services of a speech-language pathologist (SLP). Method:…

  20. Studying Another Culture through Children's Games: Examples from Nigeria.

    ERIC Educational Resources Information Center

    Sunal, Cynthia Szymanski

    1988-01-01

    Identifying games as being common to children worldwide, Sunal focuses on Nigerian group games in order to illustrate the range of game variations and their use in a social studies program. Describes hiding games, singing games, and a fine-motor skills game, stating that they help acquaint students with foreign cultures and reveal similarities in…

  1. Trends in Resource Utilization by Children with Neurological Impairment in the United States Inpatient Health Care System: A Repeat Cross-Sectional Study

    PubMed Central

    Berry, Jay G.; Poduri, Annapurna; Bonkowsky, Joshua L.; Zhou, Jing; Graham, Dionne A.; Welch, Chelsea; Putney, Heather; Srivastava, Rajendu

    2012-01-01

    Background Care advances in the United States (US) have led to improved survival of children with neurological impairment (NI). Children with NI may account for an increasing proportion of hospital resources. However, this assumption has not been tested at a national level. Methods and Findings We conducted a study of 25,747,016 US hospitalizations of children recorded in the Kids' Inpatient Database (years 1997, 2000, 2003, and 2006). Children with NI were identified with International Classification of Diseases, 9th Revision, Clinical Modification diagnoses resulting in functional and/or intellectual impairment. We assessed trends in inpatient resource utilization for children with NI with a Mantel-Haenszel chi-square test using all 4 y of data combined. Across the 4 y combined, children with NI accounted for 5.2% (1,338,590) of all hospitalizations. Epilepsy (52.2% [n = 538,978]) and cerebral palsy (15.9% [n = 164,665]) were the most prevalent NI diagnoses. The proportion of hospitalizations attributable to children with NI did not change significantly (p = 0.32) over time. In 2006, children with NI accounted for 5.3% (n = 345,621) of all hospitalizations, 13.9% (n = 3.4 million) of bed days, and 21.6% (US$17.7 billion) of all hospital charges within all hospitals. Over time, the proportion of hospitalizations attributable to children with NI decreased within non-children's hospitals (3.0% [n = 146,324] in 1997 to 2.5% [n = 113,097] in 2006, p<.001) and increased within children's hospitals (11.7% [n = 179,324] in 1997 to 13.5% [n = 209,708] in 2006, p<0.001). In 2006, children with NI accounted for 24.7% (2.1 million) of bed days and 29.0% (US$12.0 billion) of hospital charges within children's hospitals. Conclusions Children with NI account for a substantial proportion of inpatient resources utilized in the US. Their impact is growing within children's hospitals. We must ensure that the current health care system is staffed

  2. Working Memory Arrest in Children with High-Functioning Autism Compared to Children with Attention-Deficit/Hyperactivity Disorder: Results from a 2-Year Longitudinal Study

    ERIC Educational Resources Information Center

    Andersen, Per N.; Skogli, Erik W.; Hovik, Kjell T.; Geurts, Hilde; Egeland, Jens; Øie, Merete

    2015-01-01

    The aim of this study was to analyse the development of verbal working memory in children with high-functioning autism compared to children with attention-deficit/hyperactivity disorder and typically developing children. A total of 34 children with high-functioning autism, 72 children with attention-deficit/hyperactivity disorder and 45 typically…

  3. A Cross-Sectional Study of Shared Attention by Children with Autism and Typically Developing Children in an Inclusive Preschool Setting

    ERIC Educational Resources Information Center

    Rice, Catherine E.; Adamson, Lauren B.; Winner, Ellen; McGee, Gail G.

    2016-01-01

    This study examined the ways in which young children with autism and typical children focus their engagement with objects and people (peers and adults) in an inclusive preschool setting. A cross-sectional analysis was conducted of 30 typical children and 30 children with autism, with 10 different children from each group at 3 different ages (2, 3,…

  4. A 50 AH nickel cadmium battery activation and charge retention parametric study for LANDSAT-D

    NASA Technical Reports Server (NTRS)

    Tasevoli, M.

    1982-01-01

    An alternate nickel-cadmium cell activation scheme was developed which significantly reduces battery dissipation while maintaining the cell active material in the proper electrochemical state. The new procedure of charging at C/20 for 8 hours, C/10 for 6 hours and followed by C/5 to a voltage limit of 1.430 volt/cell significantly reduces the heat dissipation and charge period when compared to the standard activation practice of charging at C/20 for 48 hours. In addition, subsequent discharge voltage profiles using the new scheme are higher when compared to the standard practice. The effects of extended open-circuit periods on nickel-cadmium cell results in a capacity loss of approximately 0.7 percent and 1.4 percent per day at 23 and 35 degrees Celsius, respectively.

  5. Study on Image Drift Induced by Charging during Observation by Scanning Electron Microscope

    NASA Astrophysics Data System (ADS)

    Okai, Nobuhiro; Sohda, Yasunari

    2012-06-01

    The mechanism of image drift in the observation of a boundary between a metal and an insulator by scanning electron microscope (SEM) is clarified by electron-trajectory simulation and experiment. In the region involving a straight boundary between a large-area metal layer and an insulating substrate, the largest image drift is expected to be observed owing to an asymmetric charging on the sample surface. The simulation result shows that a metal-insulator boundary in the SEM image shifts toward the metal part over several seconds, which is induced by a positively charged area outside of the irradiation region in the insulator part. This simulation result is confirmed to qualitatively coincide with the experimental one. In addition, we demonstrate that the direction and magnitude of the image drift can be controlled by changing the charging voltage of the insulating substrate by applying a bias voltage to the anode facing the sample surface.

  6. Optical spectroscopy to study confined and semi-closed explosions of homogeneous and composite charges

    NASA Astrophysics Data System (ADS)

    Maiz, Lotfi; Trzciński, Waldemar A.; Paszula, Józef

    2017-01-01

    Confined and semi-closed explosions of new class of energetic composites as well as TNT and RDX charges were investigated using optical spectroscopy. These composites are considered as thermobarics when used in layered charges or enhanced blast explosives when pressed. Two methods to estimate fireball temperature histories of both homogeneous and metallized explosives from the spectroscopic data are also presented, compared and analyzed. Fireball temperature results of the charges detonated in a small explosion chamber under air and argon atmospheres, and detonated in a semi-closed bunker are presented and compared with theoretical ones calculated by a thermochemical code. Important conclusions about the fireball temperatures and the physical and chemical phenomena occurring after the detonation of homogeneous explosives and composite formulations are deduced.

  7. Botulinum toxin injections into salivary glands to decrease oral secretions in CHARGE syndrome: prospective case study.

    PubMed

    Blake, Kim D; MacCuspie, Jillian; Corsten, Gerard

    2012-04-01

    CHARGE syndrome is a genetic disorder caused by a mutation in the CHD7 gene on chromosome 8. Major clinical diagnostic criteria for this heterogeneous disorder include ocular coloboma, choanal atresia/stenosis, characteristic external and internal ear abnormalities, and cranial nerve abnormalities. Patients with CHARGE syndrome often have dysphagia and are at high risk for aspiration of both upper and lower gastrointestinal secretions. The following case-report describes the use of Botulinum toxin A (Botox) to reduce excess salivary secretions in a ventilator dependant infant who would have required a tracheotomy. Thereafter, Botox was used regularly (4-5 months) to decrease the salivary secretions. This case-report is unique in that it describes the intermittent and prospective use of Botox to reduce excess salivary secretions and prevent the resulting aspiration-related complications in an infant with CHARGE syndrome.

  8. Calculating potential of mean force between like-charged nanoparticles: A comprehensive study on salt effects

    NASA Astrophysics Data System (ADS)

    Wu, Yuan-Yan; Wang, Feng-Hua; Tan, Zhi-Jie

    2013-10-01

    Ions are critical to the structure and stability of polyelectrolytes such as nucleic acids. In this work, we systematically calculated the potentials of mean force between two like-charged nanoparticles in salt solutions by Monte Carlo simulations. The pseudo-spring method is employed to calculate the potential of mean force and compared systematically with the inversed-Boltzmann method. An effective attraction is predicted between two like-charged nanoparticles in divalent/trivalent salt solution and such attraction becomes weakened at very high salt concentration. Our analysis reveals that for the system, the configuration of ion-bridging nanoparticles is responsible for the attraction, and the invasion of anions into the inter-nanoparticles region at high salt concentration would induce attraction weakening rather than the charge inversion effect. The present method would be useful for calculating effective interactions during nucleic acid folding.

  9. Children's understanding of scientific concepts: A developmental study

    NASA Astrophysics Data System (ADS)

    Bickerton, Gillian Valerie

    Combining theory-oriented inquiry and research that aims to improve instruction is a major goal of neo-Piagetian theory. Within this tradition, Case's (1992) developmental model enables educational researchers to conduct a detailed analysis of the structural and conceptual changes that occur in children's representation of knowledge in different domains at various points in their development. In so doing, it is now possible for educators to first assess children's "entering competence" in a specific subject and then set developmentally realistic instructional goals. Using Case's (1992) model as a theoretical framework, a developmental study was conducted investigating children's understanding of scientific phenomena, specifically buoyancy, at the ages of 6, 8, and 10 years. The main goal was to determine whether or not children's conceptual levels of understanding change systematically with age in a progressive manner consistent with neo-Piagetian stages of development hypothesized by Case. Participants attended one elementary school in a suburban school district near Vancouver, B.C. Sixty children were individually administered a set of five buoyancy tasks that varied in level of difficulty and involved objects of different weights, shapes and sizes. Each student was asked to predict whether an object would float or sink in different liquids and to support their prediction with an explanation. Analyses using the neo-Piagetian approach of articulating the semantic and syntactic nature of children's mental structures were conducted on the students' responses. Shape, size, weight and substance were identified as the semantic components of buoyancy which are syntactically related Using Case's dimensional metric for classifying different levels of conceptual understanding of buoyancy, the results of the study confirmed that children's understanding of buoyancy did progress through the developmental sequence as hypothesized. The structural progression from

  10. A study of purely leptonic decays of the charged B meson

    NASA Astrophysics Data System (ADS)

    Hopman, Pablo

    2000-10-01

    We search for the decay B+ --> τ +ντ in a sample of 9.7 million charged B decays taken at the Υ(4S) using the CLEO detector. To tag this decay, we look at events where one of the charged B's is fully reconstructed and require that the rest of the event be consistent with the other B decaying via B + --> τ+ντ. We set an upper limit on the branching fraction B (B+ --> τ +ντ) < 8.4 × 10-4 at the 90% confidence level.

  11. Base Sequence Effects on Charge Carrier Generation in Dna:. a Theoretical Study

    NASA Astrophysics Data System (ADS)

    Starikov, E. B.; Lewis, J. P.; Sankey, O. F.

    We have thoroughly analyzed the electronic structure of stacked DNA Watson-Crick (WC) base pair dimers using ab initio Hartree-Fock and semiempirical Hartree-Fock-configuration-interaction quantum chemistry. We consider all the possible base compositions and sequences at the nucleoside level in vacuo. The results show that in such systems charge carrier generation could in principle be possible via charge transfer excitons, which turn out to dominate the first excited electronic states of the WC base pairs and their stacked dimers, and this process is largely sequence- and conformation-dependent. Possible consequences of this result for polymeric DNA duplexes are discussed.

  12. Charge accumulation at the interface of polymer/fullerene studied by double-pulse photocurrent responses

    NASA Astrophysics Data System (ADS)

    Jin, Hui; Hou, Yan-Bing; Meng, Xian-Guo; Teng, Feng

    2008-12-01

    Transport mechanism of photogenerated carriers in composite films based on Poly [2-methoxy,5-(2'-ethylhexyloxy)-1,4,-phenylene-vinylene] (MEH-PPV) doped with fullerene (C 60) is investigated by double-light-pulse induced photocurrent responses. Charge accumulation is found in low concentration ranges of C 60, while at high C 60 concentration (50 wt%), the same feature is completely absent. Charge accumulation at the interface between MEH-PPV and C 60 directly reduces the external quantum efficiency of composite devices.

  13. Photoinduced intramolecular charge transfer process of betaine pyridinium: A theoretical spectroscopic study

    NASA Astrophysics Data System (ADS)

    Perrier, Aurélie; Aloïse, Stéphane; Pawlowska, Zuzanna; Sliwa, Michel; Maurel, François; Abe, Jiro

    2011-10-01

    Using Time-Dependent Density Functional Theory and taking into account bulk solvent effects, we investigate the absorption and emission spectra of a betaine pyridinium molecule, the 2-(1-pyridinio) benzimidazolate (SBPa). This molecule exhibits strong photoinduced intramolecular charge transfer (ICT). We have identified two different electronic states involved, respectively, in the strong bathochromic ICT absorption band (S 2) and in the moderate emission band (S 1). The ICT process is analyzed in terms of charge distribution and dipole moment evolutions upon photoexcitation. These results are compared with steady-state spectroscopic measurements.

  14. Daily living pain assessment in children with autism: Exploratory study.

    PubMed

    Dubois, A; Michelon, C; Rattaz, C; Zabalia, M; Baghdadli, A

    2017-03-01

    This study aims to broaden knowledge about pain expression and assessment in daily life situations in children with Autism Spectrum Disorder (ASD). The goals are to provide a description of the responses of the GED-DI, the French version of the NCCPC, and to test the internal structure validity of this scale. Thirty five children with ASD were included in this study (mean age=58months; mean developmental age=32months). The French version of the NCCPC was filled in by parents. Descriptive analysis of responses shows that children with ASD express pain through varied and common behaviours, related to different expressive markers (vocal, facial, activity, etc.). Behaviours more specific to the symptomology and disturbances of ASD are also displayed. A four-factor solution (negative emotional reaction, idiosyncratic expression, hyper-vigilance reaction, pain expression) emerges from an exploratory factor analysis that explains 54.4% of the total variance. Correlation coefficients show good psychometric qualities in terms of internal consistency, factorial validity and discriminant validity. This study provides new data about pain expression in daily life situations and shows that the French version of NCCPC adjusted to ASD children is relevant to assess pain in daily life situations.

  15. A study on the effects of relativistic heavy charged particles on the cellular microenvironment

    NASA Astrophysics Data System (ADS)

    Costes, Sylvain Vincent

    This study was done under the National Aeronautics Space Administration (NASA) effort to assess the effect of cosmic radiation on astronauts during a 3 year mission to Mars. Carcinogenesis is known to be induced more efficiently by cosmic radiation. Our attention was turned towards one of the most efficient cosmic particles in inducing cancer, relativistic Fe, and focused in assessing its effect on the cellular microenvironment (ECM). Previous observations on mammary glands were showing irregularities in the immunoreactivity of the ECM protein laminin one hour after whole body irradiation with 1GeV/amu Fe ions for a dose of 0.8 Gy. This effect was not observed after 5 Gy γ-rays exposure. The rapidity of such a change suggested that the effect might be due to a physical event specific to relativistic charged particles (HZE), rather than a biological event. Our study showed that this effect is actually a complex and rapid response of the microenvironment to highly ionizing radiation. It involves a fast disruption of the basement membrane of the ECM induced by the highly localized ionization and reactive oxygen formation around the track of the Fe ion. This disruption triggers further chemical and biological responses involved in the remodeling of the laminin network in the basement membrane. A metalloproteinase is suspected to be the intermediate protease affecting laminin. The HZE effect on the microenvironment was seen in both mouse mammary glands and skin, but the laminin isoforms sensitive to Fe ions were different for each organ, with a clear disruption of laminin-1 network in skin and of laminin-5 in mammary glands. In addition, the laminin receptor integrins seem to be involved in this mechanism, but its contribution is unclear at this point. Finally, such studies suggest a shift from the concept of relative biological effectiveness (RBE) used in classical radiation biology since the effect is only seen with HZE at viable whole body doses. In addition, this

  16. Experimental studies of light-induced charge transfer and charge redistribution in (X(2)-bipyridine)Re(I)(CO)(3)Cl complexes.

    PubMed

    Walters, Keith A; Kim, Young-Jin; Hupp, Joseph T

    2002-06-03

    Stark emission spectroscopy, transient DC photoconductivity (TDCP), and ground-state dipole moment measurements have been used to evaluate charge transfer (CT) within various (X(2)-bipyridine)Re(I)(CO)(3)Cl complexes following (3)MLCT excited-state formation. The Stark technique reports on vector differences between ground-state (mu(g)) and excited-state (mu(e)) dipole moments, while TDCP, when combined with independently obtained mu(g) information, reports on scalar differences. For systems featuring collinear, same-signed ground- and excited-state dipole moments, the scalar and vector differences are equivalent. However, for the low symmetry systems studied here, they are distinctly different. The vector difference yields the effective adiabatic one-electron-transfer distance (R(12)), while the combined vector and scalar data yield information about dipole rotation upon ground-state/excited-state interconversion. For the systems examined, charge transfer distances are substantially smaller than geometric electron-donor/electron-acceptor site separation distances. The measured distances are significantly affected by changes in acceptor ligand substituent composition. Electron-donating substituents decrease CT distances, while electron-withdrawing substituents increase CT distances, as do aromatic substituents that are capable of expanding the bipyridyl ligand (acceptor ligand) pi system. The Stark measurements additionally indicate that the CT vector and the transition dipole moment are significantly orthogonal, a consequence of strong polarization of the Re-Cl bond (orthogonal to the metal/acceptor-ligand plane) in the ground electronic state and relaxation of the polarization in the upper state. The ground-state Re-Cl bond polarization is sufficiently large that the overall ground-state scalar dipole moment exceeds the overall excited-state scalar dipole moment, despite transfer of an electron from the metal center to the diimine ligand. This finding provides an

  17. Theoretical study of negatively charged Fe(-)-(H2O)(n ≤ 6) clusters.

    PubMed

    Castro, Miguel

    2012-06-14

    Interactions of a singly negatively charged iron atom with water molecules, Fe(-)-(H(2)O)(n≤6), in the gas phase were studied by means of density functional theory. All-electron calculations were performed using the B3LYP functional and the 6-311++G(2d,2p) basis set for the Fe, O, and H atoms. In the lowest total energy states of Fe(-)-(H(2)O)(n), the metal-hydrogen bonding is stronger than the metal-oxygen one, producing low-symmetry structures because the water molecules are directly attached to the metal by basically one of their hydrogen atoms, whereas the other ones are involved in a network of hydrogen bonds, which together with the Fe(δ-)-H(δ+) bonding accounts for the nascent hydration of the Fe(-) anion. For Fe(-)-(H(2)O)(3≤n), three-, four-, five-, and six-membered rings of water molecules are bonded to the metal, which is located at the surface of the cluster in such a way as to reduce the repulsion with the oxygen atoms. Nevertheless, internal isomers appear also, lying less than 3 or 5 kcal/mol for n = 2-3 or n = 4-6. These results are in contrast with those of classical TM(+)-(H(2)O)(n) complexes, where the direct TM(+)-O bonding usually produces high symmetry structures with the metal defining the center of the complex. They show also that the Fe(-) anions, as the TM(+) ions, have great capability for the adsorption of water molecules, forming Fe(-)-(H(2)O)(n) structures stabilized by Fe(δ-)-H(δ+) and H-bond interactions.

  18. Charge transport in metal oxides: A theoretical study of hematite α-Fe2O3

    NASA Astrophysics Data System (ADS)

    Iordanova, N.; Dupuis, M.; Rosso, K. M.

    2005-04-01

    Transport of conduction electrons and holes through the lattice of α-Fe2O3 (hematite) is modeled as a valence alternation of iron cations using ab initio electronic structure calculations and electron transfer theory. Experimental studies have shown that the conductivity along the (001) basal plane is four orders of magnitude larger than the conductivity along the [001] direction. In the context of the small polaron model, a cluster approach was used to compute quantities controlling the mobility of localized electrons and holes, i.e., the reorganization energy and the electronic coupling matrix element that enter Marcus' theory. The calculation of the electronic coupling followed the generalized Mulliken-Hush approach using the complete active space self-consistent field method. Our findings demonstrate an approximately three orders of magnitude anisotropy in both electron and hole mobility between directions perpendicular and parallel to the c axis, in good accord with experimental data. The anisotropy arises from the slowness of both electron and hole mobilities across basal oxygen planes relative to that within iron bilayers between basal oxygen planes. Interestingly, for elementary reaction steps along either of the directions considered, there is only less than one order of magnitude difference in mobility between electrons and holes, in contrast to accepted classical arguments. Our findings indicate that the most important quantity underlying mobility differences is the electronic coupling, albeit the reorganization energy contributes as well. The large values computed for the electronic coupling suggest that charge transport reactions in hematite are adiabatic in nature. The electronic coupling is found to depend on both the superexchange interaction through the bridging oxygen atoms and the d-shell electron spin coupling within the Fe-Fe donor-acceptor pair, while the reorganization energy is essentially independent of the electron spin coupling.

  19. Postural development in school children: a cross-sectional study

    PubMed Central

    Lafond, Danik; Descarreaux, Martin; Normand, Martin C; Harrison, Deed E

    2007-01-01

    Background Little information on quantitative sagittal plane postural alignment and evolution in children exists. The objectives of this study are to document the evolution of upright, static, sagittal posture in children and to identify possible critical phases of postural evolution (maturation). Methods A total of 1084 children (aged 4–12 years) received a sagittal postural evaluation with the Biotonix postural analysis system. Data were retrieved from the Biotonix internet database. Children were stratified and analyzed by years of age with n = 36 in the youngest age group (4 years) and n = 184 in the oldest age group (12 years). Children were analyzed in the neutral upright posture. Variables measured were sagittal translation distances in millimeters of: the knee relative to the tarsal joint, pelvis relative to the tarsal joint, shoulder relative to the tarsal joint, and head relative to the tarsal joint. A two-way factorial ANOVA was used to test for age and gender effects on posture, while polynomial trend analyses were used to test for increased postural displacements with years of age. Results Two-way ANOVA yielded a significant main effect of age for all 4 sagittal postural variables and gender for all variables except head translation. No age × gender interaction was found. Polynomial trend analyses showed a significant linear association between child age and all four postural variables: anterior head translation (p < 0.001), anterior shoulder translation (p < 0.001), anterior pelvic translation (p < 0.001), anterior knee translation (p < 0.001). Between the ages of 11 and 12 years, for anterior knee translation, T-test post hoc analysis revealed only one significant rough break in the continuity of the age related trend. Conclusion A significant linear trend for increasing sagittal plane postural translations of the head, thorax, pelvis, and knee was found as children age from 4 years to 12 years. These postural translations provide preliminary

  20. Associations of diet quality with cognition in children - the Physical Activity and Nutrition in Children Study.

    PubMed

    Haapala, Eero A; Eloranta, Aino-Maija; Venäläinen, Taisa; Schwab, Ursula; Lindi, Virpi; Lakka, Timo A

    2015-10-14

    Evidence on the associations of dietary patterns with cognition in children is limited. Therefore, we investigated the associations of the Baltic Sea Diet Score (BSDS) and the Dietary Approaches to Stop Hypertension (DASH) score with cognition in children. The present cross-sectional study sample included 428 children aged 6-8 years (216 boys and 212 girls). The BSDS and the DASH score were calculated using data from 4 d food records, higher scores indicating better diet quality. Cognition was assessed by the Raven's Coloured Progressive Matrices (CPM) score, a higher score indicating better cognition. Among all children, the BSDS (standardised regression coefficient β = 0·122, P =0·012) and the DASH score (β = 0·121, P =0·015) were directly associated with the Raven's CPM score. Among boys, a lower BSDS (β = 0·244, P< 0·001) and a lower DASH score (β = 0·202, P= 0·003) were related to a lower Raven's CPM score. Boys in the lowest quartile of the BSDS (22·5 v. 25·3, P= 0·029) and the DASH score (22·4 v. 25·7, P= 0·008) had a lower Raven's CPM score than those in the highest quartile of the corresponding score. Among girls, the BSDS or the DASH score were not associated with cognition. In conclusion, a poorer diet quality was associated with worse cognition in children, and the relationship was stronger in boys than in girls.

  1. Do Children Who Bully Their Peers Also Play Violent Video Games? A Canadian National Study

    ERIC Educational Resources Information Center

    Dittrick, Crystal J.; Beran, Tanya N.; Mishna, Faye; Hetherington, Ross; Shariff, Shaheen

    2013-01-01

    The study examined whether children who bully others are likely to prefer playing video games that are rated high in maturity and violence. A stratified random sample of Canadian children ages 10 to 17 years from the provinces of Canada was obtained. Parents (n = 397) and their children (n = 492) completed an online survey of children's bullying…

  2. Play as a Resource for Children Facing Adversity: An Exploration of Indicative Case Studies

    ERIC Educational Resources Information Center

    Fearn, Maggie; Howard, Justine

    2012-01-01

    In this paper, we suggest that the ability and opportunity to play affords children a natural resource to meet intellectual and emotional challenge. Analysis of case studies focusing on interventions with children caught in the bombing of Beirut, children abandoned to the state system in Romania, and the street children in Rio de Janeiro and Cali…

  3. The Pittsburgh Children's Museum. Study Guides.

    ERIC Educational Resources Information Center

    Donley, Susan K.; And Others

    These five study guides present ideas for activities based on museum exhibition themes. The learning activities are designed for coordination with museum visits, but may be adapted for independent use. Activities appropriate for preschool and elementary levels are indicated. Exhibition themes include: (1) "Space Exploration," which…

  4. Solid-state NMR Study of Ion Adsorption and Charge Storage in Graphene Film Supercapacitor Electrodes

    PubMed Central

    Li, Kecheng; Bo, Zheng; Yan, Jianhua; Cen, Kefa

    2016-01-01

    Graphene film has been demonstrated as promising active materials for electric double layer capacitors (EDLCs), mainly due to its excellent mechanical flexibility and freestanding morphology. In this work, the distribution and variation pattern of electrolyte ions in graphene-film based EDLC electrodes are investigated with a 11B magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. For neutral graphene films soaked with different amounts of electrolytes (1 M TEABF4/ACN), weakly and strongly adsorbed anions are identified based on the resonances at different 11B chemical shifts. Unlike other porous carbonaceous materials, the strongly adsorbed anions are found as the major electrolyte anions components in graphene films. Further measurements on the ion population upon charging are carried out with applying different charging voltages on the graphene films. Results indicate that the charging process of graphene-film based EDLCs can be divided into two distinct charge storage stages (i.e., ejection of co-ions and adsorption of counter-ions) for different voltages. The as-obtained results will be useful for the design and fabrication of high performance graphene-film based EDLCs. PMID:28000786

  5. Solid-state NMR Study of Ion Adsorption and Charge Storage in Graphene Film Supercapacitor Electrodes

    NASA Astrophysics Data System (ADS)

    Li, Kecheng; Bo, Zheng; Yan, Jianhua; Cen, Kefa

    2016-12-01

    Graphene film has been demonstrated as promising active materials for electric double layer capacitors (EDLCs), mainly due to its excellent mechanical flexibility and freestanding morphology. In this work, the distribution and variation pattern of electrolyte ions in graphene-film based EDLC electrodes are investigated with a 11B magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. For neutral graphene films soaked with different amounts of electrolytes (1 M TEABF4/ACN), weakly and strongly adsorbed anions are identified based on the resonances at different 11B chemical shifts. Unlike other porous carbonaceous materials, the strongly adsorbed anions are found as the major electrolyte anions components in graphene films. Further measurements on the ion population upon charging are carried out with applying different charging voltages on the graphene films. Results indicate that the charging process of graphene-film based EDLCs can be divided into two distinct charge storage stages (i.e., ejection of co-ions and adsorption of counter-ions) for different voltages. The as-obtained results will be useful for the design and fabrication of high performance graphene-film based EDLCs.

  6. Solid-state NMR Study of Ion Adsorption and Charge Storage in Graphene Film Supercapacitor Electrodes.

    PubMed

    Li, Kecheng; Bo, Zheng; Yan, Jianhua; Cen, Kefa

    2016-12-21

    Graphene film has been demonstrated as promising active materials for electric double layer capacitors (EDLCs), mainly due to its excellent mechanical flexibility and freestanding morphology. In this work, the distribution and variation pattern of electrolyte ions in graphene-film based EDLC electrodes are investigated with a (11)B magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. For neutral graphene films soaked with different amounts of electrolytes (1 M TEABF4/ACN), weakly and strongly adsorbed anions are identified based on the resonances at different (11)B chemical shifts. Unlike other porous carbonaceous materials, the strongly adsorbed anions are found as the major electrolyte anions components in graphene films. Further measurements on the ion population upon charging are carried out with applying different charging voltages on the graphene films. Results indicate that the charging process of graphene-film based EDLCs can be divided into two distinct charge storage stages (i.e., ejection of co-ions and adsorption of counter-ions) for different voltages. The as-obtained results will be useful for the design and fabrication of high performance graphene-film based EDLCs.

  7. Charge injection and Raman scattering studies from polyfluorene-based light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Arif, M.; Guha, S.

    2007-03-01

    Efficient and well balanced injection of charge carriers and transport capabilities are of particular importance for high luminescence efficiency in organic light-emitting diodes. Polyfluorene (PF) conjugated polymers have received widespread attention due to their strong blue emission, high charge mobility and excellent chemical and thermal stability which creates great prospect for optoelectronic device applications. Although ethyl-hexyl substituted PF (PF2/6) has a high level of molecular disorder, charge injection in single layer polymer devices can be described very well by space-charge-limited conduction for a discrete set of trap levels. This is attributed to the nature of ordering in the polymer. PFs are characterized by a number of Raman-active peaks originating from C-H bending and C-C stretching type motion. We further analyze our working devices using Raman scattering in the presence of photogenerated carriers. The Raman intensities in the 1000-1250 cm-1 corresponding to a C-H bend-type motion quench in the presence of carriers with increasing fields. This effect most probably arises due to the interaction of phonons and free carriers.

  8. A study of spacecraft charging due to exposure to interplanetary protons

    NASA Technical Reports Server (NTRS)

    Green, Nelson W.; Frederickson, A. Robb

    2006-01-01

    The majority of research regarding IESD has been concerned with the electrons in the space environment around the Earth and at Jupiter; little research has been done on the charging of spacecraft in interplanetary space due to solar event protons. This paper provides a review of the literature regarding IESD due to protons and presents the results of recent laboratory experiments.

  9. A Study of Spacecraft Charging Due to Exposure to Interplanetary Protons

    NASA Technical Reports Server (NTRS)

    Green, Nelson W.; Frederickson, A. Robb

    2006-01-01

    Long life spacecraft may be exposed to one or more major solar storms during the mission lifespan. This research task was undertaken to determine the risk to long duration interplanetary spacecraft from spacecraft charging due to exposure to solar energetic protons.

  10. Dynamic aperture and space charge effect studies for the Recycler ring for Project-X

    SciTech Connect

    Xiao, M.; Vorobiev, L.G.; Johnson, D.E.; /Fermilab

    2010-09-01

    A simplified Recycler lattice was created to fine tune injection straight, ring tune, and phase trombone. In this paper, we will present detailed modifications for further optimization of Recycler lattice which requires the investigation of tune footprint and dynamic aperture based on higher order momentum components of the magnetic fields, together with the space charge effects.

  11. Brownian-dynamics simulation studies of a charge-stabilized colloidal suspension under shear flow

    SciTech Connect

    Chakrabarti, J. ); Sood, A.K.; Krishnamurthy, H.R. Jawaharlal Nehru Center for Advanced Scientific Research, Indian Institute of Science campus, Bangalore 560012 )

    1994-11-01

    We have carried out Brownian-dynamics simulations of a charged colloidal suspension under oscillatory shear flow with both Couette and Poiseuille velocity profiles. We show that in the steady-shear'' limit, for both of the velocity profiles, the enhancement of the self-diffusion coefficient in directions transverse to the flow shows a crossover from a [dot [gamma

  12. High-Level Spacecraft Charging in Eclipse at Geosynchronous Altitudes: A Statistical Study

    DTIC Science & Technology

    2006-01-01

    event in the recent solar maximum was the Bastille Day (14 July 2000) storm. The quadratic fits were done next. The quadratic fits were Figure 6 shows...temperatures, and Kp~ inidex in the Bastille Day, 2000, geomagnetic storm. high-voltage spacecraft charging to commence. The idea of atures are mostly

  13. Surface charge determines the lung inflammogenicity: A study with polystyrene nanoparticles.

    PubMed

    Kim, Jeongeun; Chankeshwara, Sunay V; Thielbeer, Frank; Jeong, Jiyoung; Donaldson, Ken; Bradley, Mark; Cho, Wan-Seob

    2016-01-01

    Surface functionalization is a routine process to improve the behavior of nanoparticles (NPs), but the induced surface properties, such as surface charge, can produce differential toxicity profiles. Here, we synthesized a library of covalently functionalized fluorescent polymeric NPs (F-PLNPs) to evaluate the role of surface charge on the acute inflammation and the localization in the lung. Guanidinium-, acetylated-, zwitterionic-, hydroxylated-, PEGylated-, carboxylated- and sulfated-F-PLNPs were synthesized from aminated-F-PLNP. The primary particle sizes were identical, but the hydrodynamic sizes ranged from 210 to 345 nm. Following surface functionalization, the F-PLNPs showed diverse zeta potentials from -41.2 to 31.0 mV, and each F-PLNP showed a single, narrow peak. Pharyngeal aspiration with these eight types of F-PLNPs into rats produced diverse acute lung inflammation, with zeta potentials of the F-PLNPs showing excellent correlation with acute pulmonary inflammation parameters including the percentage of polymorphonuclear leukocytes (R(2) = 0.90, p < 0.0001) and the levels of interleukin-1β (R(2) = 0.83, p < 0.0001) and of cytokine-induced neutrophil chemoattractant-3 (R(2) = 0.86, p < 0.0001). These results imply that surface charge is a key factor influencing lung inflammation by functionalized polymeric NPs, which further confirms and extends the surface charge paradigm that we reported for pristine metal oxide NPs. This demonstrates that the surface charge paradigm is a valuable tool to predict the toxicity of NPs.

  14. USE OF BIOMARKERS TO INDICATE EXPOSURE OF CHILDREN TO ORGANOPHOSPATE PESTICIDES: IMPLICATIONS FOR A LONGITUDINAL STUDY OF CHILDREN'S ENVIRONMENTAL HEALTH

    EPA Science Inventory

    Because of their widespread use in the U.S. and unkown long-term health effects, planning for the National Children's Study (NCS) includes consideration of organophosphate pestcides (OPs) as a chemical class of interest in a longitudinal study of children's environmental health...

  15. A NORMATIVE STUDY OF CHILDREN'S HOUSE-TREE-PERSON DRAWINGS.

    ERIC Educational Resources Information Center

    RAPPAPORT, SHELDON R.

    THIS STUDY WAS THE FIRST PHASE OF A THREE-PART PROJECT WHOSE GOAL IS TO ESTABLISH VALID CRITERIA FOR IDENTIFYING THE HOUSE-TREE-PERSON (H-T-P) DRAWINGS OF NORMAL CHILDREN THROUGHOUT THE ELEMENTARY SCHOOL YEARS. THE SPECIFIC OBJECTIVES OF THIS STUDY WERE (1) TO IDENTIFY WHICH ITEMS OF THE H-T-P TEST CHARACTERIZE NORMAL DEVELOPMENT THROUGH GRADES 2,…

  16. Children with Autism Show Reduced Somatosensory Response: An MEG Study

    PubMed Central

    Marco, Elysa J.; Khatibi, Kasra; Hill, Susanna S.; Siegel, Bryna; Arroyo, Monica S.; Dowling, Anne F.; Neuhaus, John M.; Sherr, Elliott H.; Hinkley, Leighton N. B.; Nagarajan, Srikantan S.

    2012-01-01

    Lay Abstract Autism spectrum disorders are reported to affect nearly one out of every one hundred children, with over 90% of these children showing behavioral disturbances related to the processing of basic sensory information. Behavioral sensitivity to light touch, such as profound discomfort with clothing tags and physical contact, is a ubiquitous finding in children on the autism spectrum. In this study, we investigate the strength and timing of brain activity in response to simple, light taps to the fingertip. Our results suggest that children with autism show a diminished early response in the primary somatosensory cortex (S1). This finding is most evident in the left hemisphere. In exploratory analysis, we also show that tactile sensory behavior, as measured by the Sensory Profile, may be a better predictor of the intensity and timing of brain activity related to touch than a clinical autism diagnosis. We report that children with atypical tactile behavior have significantly lower amplitude somatosensory cortical responses in both hemispheres. Thus sensory behavioral phenotype appears to be a more powerful strategy for investigating neural activity in this cohort. This study provides evidence for atypical brain activity during sensory processing in autistic children and suggests that our sensory behavior based methodology may be an important approach to investigating brain activity in people with autism and neurodevelopmental disorders. Scientific Abstract The neural underpinnings of sensory processing differences in autism remain poorly understood. This prospective magnetoencephalography (MEG) study investigates whether children with autism show atypical cortical activity in the primary somatosensory cortex (S1) in comparison to matched controls. Tactile stimuli were clearly detectable, painless taps applied to the distal phalanx of the second (D2) and third (D3) fingers of the right and left hands. Three tactile paradigms were administered: an oddball

  17. Prospective Multicenter Study of Children With Bronchiolitis Requiring Mechanical Ventilation

    PubMed Central

    Piedra, Pedro A.; Stevenson, Michelle D.; Sullivan, Ashley F.; Forgey, Tate F.; Clark, Sunday; Espinola, Janice A.; Camargo, Carlos A.

    2012-01-01

    OBJECTIVE: To identify factors associated with continuous positive airway pressure (CPAP) and/or intubation for children with bronchiolitis. METHODS: We performed a 16-center, prospective cohort study of hospitalized children aged <2 years with bronchiolitis. For 3 consecutive years from November 1 until March 31, beginning in 2007, researchers collected clinical data and a nasopharyngeal aspirate from study participants. We oversampled children from the ICU. Samples of nasopharyngeal aspirate were tested by polymerase chain reaction for 18 pathogens. RESULTS: There were 161 children who required CPAP and/or intubation. The median age of the overall cohort was 4 months; 59% were male; 61% white, 24% black, and 36% Hispanic. In the multivariable model predicting CPAP/intubation, the significant factors were: age <2 months (odds ratio [OR] 4.3; 95% confidence interval [CI] 1.7–11.5), maternal smoking during pregnancy (OR 1.4; 95% CI 1.1–1.9), birth weight <5 pounds (OR 1.7; 95% CI 1.0–2.6), breathing difficulty began <1 day before admission (OR 1.6; 95% CI 1.2–2.1), presence of apnea (OR 4.8; 95% CI 2.5–8.5), inadequate oral intake (OR 2.5; 95% CI 1.3–4.3), severe retractions (OR 11.1; 95% CI 2.4–33.0), and room air oxygen saturation <85% (OR 3.3; 95% CI 2.0–4.8). The optimism-corrected c-statistic for the final model was 0.80. CONCLUSIONS: In this multicenter study of children hospitalized with bronchiolitis, we identified several demographic, historical, and clinical factors that predicted the use of CPAP and/or intubation, including children born to mothers who smoked during pregnancy. We also identified a novel subgroup of children who required mechanical respiratory support <1 day after respiratory symptoms began. PMID:22869823

  18. Study of the effect of the charge transport layer in the electrical characteristics of the organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Rahimi, Ronak; Roberts, Alex; Narang, V.; Kumbham, Vamsi Krishna; Korakakis, D.

    2013-09-01

    Significant progress in fabrication and optimization of organic photovoltaics (OPVs) has been made during the last decade. The main reason for popularity of OPVs is due to their low production cost, large area devices and compatibility with flexible substrates 1-3. Various approaches including optimizing morphology of the active layers 1, 2, introducing new materials as the donor and acceptor 3,4, new device structures such as tandem structure 5, 6 have been adapted to improve the efficiency of the organic photovoltaics. However, electrical characteristics of the OPVs do not only depend on the active layer materials or device structure. They can also be defined by the interface properties between active layers and the charge transport layers or the metal contacts. Within this paper, the effect of the thickness variation of the charge transport layer in the electrical properties of the bilayer heterojunction OPVs has been studied. Several devices with CuPc/PTCDI-C8 as the donor/acceptor layers have been fabricated with different thicknesses of electron transport layer. MoO3 and Alq3 have been used respectively as the hole transport layer (HTL) and the electron transport layer (ETL). It has been shown that the S-shape effect in the current-voltage curve is attributed to the accumulation of the charge carriers at the interface between the active layer and the charge transport layer 5, 7.

  19. Study of the effect of the charge transport layer in the electrical characteristics of the organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Rahimi, Ronak; Roberts, Alex; Narang, V.; Kumbham, Vamsi Krishna; Korakakis, D.

    2013-03-01

    Significant progress in fabrication and optimization of organic photovoltaics (OPVs) has been made during the last decade. The main reason for popularity of OPVs is due to their low production cost, large area devices and compatibility with flexible substrates [1-3]. Various approaches including optimizing morphology of the active layers [1,2], introducing new materials as the donor and acceptor [3,4], new device structures such as tandem structure [5,6] have been adapted to improve the efficiency of the organic photovoltaics. However, electrical characteristics of the OPVs do not only depend on the active layer materials or device structure. They can also be defined by the interface properties between active layers and the charge transport layers or the metal contacts. Within this paper, the effect of the thickness variation of the charge transport layer in the electrical properties of the bilayer heterojunction OPVs has been studied. Several devices with CuPc/PTCDI-C8 as the donor/acceptor layers have been fabricated with different thicknesses of electron transport layer. MoO3 and Alq3 have been used respectively as the hole transport layer (HTL) and the electron transport layer (ETL). It has been shown that the S-shape effect in the current-voltage curve is attributed to the accumulation of the charge carriers at the interface between the active layer and the charge transport layer [5,7].

  20. Charged nanoparticle attraction in multivalent salt solution: A classical-fluids density functional theory and molecular dynamics study

    DOE PAGES

    Salerno, K. Michael; Frischknecht, Amalie L.; Stevens, Mark J.

    2016-04-08

    Here, negatively charged nanoparticles (NPs) in 1:1, 1:2, and 1:3 electrolyte solutions are studied in a primitive ion model using molecular dynamics (MD) simulations and classical density functional theory (DFT). We determine the conditions for attractive interactions between the like-charged NPs. Ion density profiles and NP–NP interaction free energies are compared between the two methods and are found to be in qualitative agreement. The NP interaction free energy is purely repulsive for monovalent counterions, but can be attractive for divalent and trivalent counterions. Using DFT, the NP interaction free energy for different NP diameters and charges is calculated. The depthmore » and location of the minimum in the interaction depend strongly on the NPs’ charge. For certain parameters, the depth of the attractive well can reach 8–10 kBT, indicating that kinetic arrest and aggregation of the NPs due to electrostatic interactions is possible. Rich behavior arises from the geometric constraints of counterion packing at the NP surface. Layering of counterions around the NPs is observed and, as secondary counterion layers form the minimum of the NP–NP interaction free energy shifts to larger separation, and the depth of the free energy minimum varies dramatically. We find that attractive interactions occur with and without NP overcharging.« less

  1. Computational study of the energetics of charge and cation mixing in U1-xCexO₂

    DOE PAGES

    Hanken, B. E.; Stanek, C. R.; Grønbech-Jensen, N.; ...

    2011-08-26

    The formalism of electronic density-functional theory (DFT), with Hubbard-U corrections (DFT+U), is employed in a computational study of the energetics of fluorite-structured U1-xCexO₂ mixtures. The computational approach makes use of a procedure which facilitates convergence of the calculations to multiple self-consistent DFT+U solutions for a given cation arrangement, corresponding to different charge states for the U and Ce ions in several prototypical cation arrangements. Results indicate a significant dependence of the structural and energetic properties on the nature of both charge and cation ordering. With the effective Hubbard-U parameters that reproduce well the measured oxidation-reduction energies for urania and ceria,more » we find that charge transfer between U⁴⁺ and Ce⁴⁺ ions, leading to the formation of U⁵⁺ and Ce³⁺, gives rise to an increase in the mixing energy in the range of 4–14 kJ/mol of the formula unit, depending on the nature of the cation ordering. The results suggest that although charge transfer between uranium and cerium ions is disfavored energetically, it is likely to be entropically stabilized at the high temperatures relevant to the processing and service of urania-based solid solutions.« less

  2. Theoretical and experimental study of charge transfer through DNA: impact of mercury mediated T-Hg-T base pair.

    PubMed

    Kratochvílová, Irena; Golan, Martin; Vala, Martin; Špérová, Miroslava; Weiter, Martin; Páv, Ondřej; Šebera, Jakub; Rosenberg, Ivan; Sychrovský, Vladimír; Tanaka, Yoshiyuki; Bickelhaupt, F Matthias

    2014-05-22

    DNA-Hg complexes may play an important role in sensing DNA defects or in detecting the presence of Hg in the environment. A fundamental way of characterizing DNA-Hg complexes is to study the way the electric charge is transferred through the molecular chain. The main goal of this contribution was to investigate the impact of a mercury metal cation that links two thymine bases in a DNA T-T mismatched base pair (T-Hg-T) on charge transfer through the DNA molecule. We compared the charge transfer efficiencies in standard DNA, DNA with mismatched T-T base pairs, and DNA with a T-Hg(II)-T base pair. For this purpose, we measured the temperature dependence of steady-state fluorescence and UV-vis of the DNA molecules. The experimental results were confronted with the results obtained employing theoretical DFT methods. Generally, the efficiency of charge transfer was driven by mercury changing the spatial overlap of bases.

  3. Charged nanoparticle attraction in multivalent salt solution: A classical-fluids density functional theory and molecular dynamics study

    SciTech Connect

    Salerno, K. Michael; Frischknecht, Amalie L.; Stevens, Mark J.

    2016-04-08

    Here, negatively charged nanoparticles (NPs) in 1:1, 1:2, and 1:3 electrolyte solutions are studied in a primitive ion model using molecular dynamics (MD) simulations and classical density functional theory (DFT). We determine the conditions for attractive interactions between the like-charged NPs. Ion density profiles and NP–NP interaction free energies are compared between the two methods and are found to be in qualitative agreement. The NP interaction free energy is purely repulsive for monovalent counterions, but can be attractive for divalent and trivalent counterions. Using DFT, the NP interaction free energy for different NP diameters and charges is calculated. The depth and location of the minimum in the interaction depend strongly on the NPs’ charge. For certain parameters, the depth of the attractive well can reach 8–10 kBT, indicating that kinetic arrest and aggregation of the NPs due to electrostatic interactions is possible. Rich behavior arises from the geometric constraints of counterion packing at the NP surface. Layering of counterions around the NPs is observed and, as secondary counterion layers form the minimum of the NP–NP interaction free energy shifts to larger separation, and the depth of the free energy minimum varies dramatically. We find that attractive interactions occur with and without NP overcharging.

  4. A Developmental Study of Chinese Children's Word and Character Reading

    ERIC Educational Resources Information Center

    Li, Tong; Wang, Ying; Tong, Xiuhong; McBride, Catherine

    2017-01-01

    To investigate the relationship between Chinese children's character and word reading, 62 third and 50 fifth grade children in Hong Kong were asked to read single characters and words that were comprised of these characters. Results showed that words helped children to recognize characters for both grades of children. Compared to older children,…

  5. [Study on casein allergy in children].

    PubMed

    Hasegawa, D; Kawashima, H; Oana, S; Motobe, M; Iiyama, M; Kashiwagi, Y; Numabe, H; Takekuma, K; Hoshika, A

    2000-11-01

    Casein a component of milk is used for food additives, industrial materials and drugs. However casein is known to be a main allergen in milk allergy. Recently several cases of anaphylaxis to antibiotics including casein have been reported. In this study we investigated casein allergy in milk allergy. 6 out of 8 patients who were positive for milk RAST were also positive for casein RAST. In these positive cases only 3 out of 6 patients had some allergic symptoms after taking antibiotics. In 3 patients DLST was also positive to casein. There was one patient who was positive in DLST without any symptoms after taking the same antibiotics. It is needed to pay attention to casein allergy when giving the medication which includes casein.

  6. Charging of interplanetary grains

    NASA Technical Reports Server (NTRS)

    Baragiola, R. A.; Johnson, R. E.; Newcomb, John L.

    1995-01-01

    The objective of this program is to quantify, by laboratory experiments, the charging of ices and other insulators subject to irradiation with electrons, ions and ultraviolet photons and to model special conditions based on the data. The system and conditions to be studied are those relevant for charging of dust in magnetospheric plasmas. The measurements are supplemented by computer simulations of charging or grains under a variety of conditions. Our work for this period involved experiments on water ice, improved models of charging of ice grains for Saturn's E-ring, and the construction of apparatus for electron impact studies and measurements of electron energy distributions.

  7. Young children's experiences of participating in group treatment for children exposed to intimate partner violence: A qualitative study.

    PubMed

    Pernebo, Karin; Almqvist, Kjerstin

    2016-01-01

    The risk of exposure to intimate partner violence (IPV) between caregivers is increased during early childhood. The adverse effects on the health and development of the youngest children may be severe. Effective and promising interventions for children who have experienced IPV have been developed and evaluated. However, there is a lack in knowledge about how the children themselves experience the interventions. The aim of this study was to contribute to the evaluation of group treatment designed to improve the psychological health of young children in the aftermath of family violence by elucidating the children's experiences of participating. Nine children, aged 4 to 6 years, were interviewed after participating in group programmes specifically designed for children who have been exposed to intimate partner violence. A semi-structured interview guide with open-ended questions was used. The interviews were transcribed and analysed using interpretative phenomenological analysis, to ensure a focus on the children's own views and experiences. Five master themes embracing the children's experiences were identified: joy - positive emotional experience of participation; security - feeling safe; relatedness - relationships within the group; to talk - externalised focus on the violence; and competence - new knowledge and skills. Theoretical and clinical implications and the benefit of including very young children's views and experiences in research are discussed.

  8. Pharmacokinetic study of metopimazine by oral route in children

    PubMed Central

    Mallet, Eric; Bounoure, Frederic; Skiba, Mohamed; Saussereau, Elodie; Goullé, Jean-Pierre; Castanet, Mireille

    2015-01-01

    Metopimazine (MPZ) is an antiemetic considered as a currently used drug. In France, it has become the leading antiemetic mediator due to its good tolerance, however, its pharmacokinetics has never previously been studied in children. MPZ was administered by oral route to 8 children with a single dose of 0.33 mg/kg during an endocrine exploration using stimuli well known for its adverse emetic effects. We used biological remnants from sera following an hGH test in order to obtain the MPZ pharmacokinetics. Plasmatic concentrations of MPZ and the active acid metabolite AMPZ, were quantified by HPLC-MS/MS during a 270 min test period. MPZ is quickly absorbed with a median Cmax of 17.2 ng/mL at one hour and its half-life is 2.18 h. The plasmatic concentrations of AMPZ were higher than MPZ with a median Cmax of 76.3 ng/mL, a Tmax to 150 min and its concentration was approximately maintained at 50 ng/mL from 1 to 4 h. The plasmatic concentrations in children are similar to those observed in adults. No adverse effects, nausea or vomiting occurred during the trial. Therefore, these results confirm the MPZ dosage that should be used in children under 15 kg administered as 0.33 mg/kg up to 3 times a day. PMID:26171218

  9. Mothers' teaching strategies and children's effortful control: a longitudinal study.

    PubMed

    Eisenberg, Nancy; Vidmar, Masa; Spinrad, Tracy L; Eggum, Natalie D; Edwards, Alison; Gaertner, Bridget; Kupfer, Anne

    2010-09-01

    Findings on the relation of maternal verbal teaching strategies to children's effortful control (EC; i.e., self-regulation) are limited in quantity and somewhat inconsistent. In this study, children's EC was assessed at 18, 30, and 42 months (ns = 255, 229, and 209, respectively) with adults' reports and a behavioral measure. Mothers' verbal teaching strategies were assessed while the mother and child worked on a task together. Children's general vocabulary also was measured. In a structural panel model taking into account prior levels of constructs and correlations within time, as well as the relations of EC and teaching strategies to children's vocabulary, socioeconomic status, age, and sex of the child, 18-month EC positively predicted mothers' 30-month cognitive assistance and questioning strategies and negatively predicted 30-month maternal directive strategies. In addition, high 30-month EC predicted greater 42-month maternal cognitive assistance and fewer directive strategies. Thus, mothers' teaching strategies were predicted by individual differences in self-regulatory skills, supporting potential evocative child effects on mothers' teaching strategies.

  10. Study of skin rashes after antibiotic use in young children.

    PubMed

    Huang, S W; Borum, P R

    1998-10-01

    Immunoglobulin E (IgE)-mediated drug sensitivity in children is uncommon. However, undefined skin rash following antibiotic ingestion in younger children is commonly observed in clinical practice. We studied 86 consecutively referred patients to our allergy clinic over a 5-year period. We found that the majority of children (80%) with skin rashes were under 3 years of age. All the children had been treated with antibiotics for a bacterial upper respiratory infection (URI; otitis media, sinusitis, or pharyngitis), 73 (85%) had erythematous rash, 13 (15%) had urticaria occurring 3-5 days after the treatment, and 43 (50%) reported a repeated rash with the use of two or more different antibiotics. There were no reports of systemic reactions or histories of accompanying food allergy. When patients were given the suspected antibiotics while they were well, none developed rash. However, in the next bacterial infection, 62 (72%) chose to receive dye-free suspensions of the suspected antibiotics. Only three patients (3.5%) elected for the dye-containing suspension. Of the 62 patients who received dye-free suspensions, only eight developed a mild skin rash, which was managed successfully. We conclude that a practical approach for non-IgE-mediated skin rash needs to be evaluated. The current practice of complete avoidance of the suspected antibiotics without further evaluation may be unwarranted.

  11. Study of spirometry in children from Mexico City

    SciTech Connect

    Namihira, D.; Strope, G.L.; Helms, R.W.; Pekow, P.; Bojalil, B.M.; Fernandez, F.

    1986-11-01

    A study was conducted in two elementary schools in Mexico City to determine values for pulmonary function tests in school-aged residents of Mexico City. The schools were located in Xalostoc, a highly industrialized area of Mexico City, and San Lorenzo, a suburban area of the city. Although data regarding atmospheric pollution were not available, there is an acknowledged higher level of macroenvironmental air pollution in Xalostoc. Pulmonary function tests were performed on 468 children in San Lorenzo and 405 children in Xalostoc. No differences between residents of the two communities for acute or chronic respiratory conditions were detected by questionnaire. The pulmonary function data demonstrate that boys have larger forced vital capacities (FVC) and forced expiratory flows over the middle half of the FVC (FEF25-75) than girls. Slopes of regression lines for FVC but not for FEF25-75 are greater in boys and girls from Xalostoc than in boys and girls from San Lorenzo. This suggests that young children from Xalostoc may experience ill effects of air pollution but develop catch-up growth later. There were no important community or gender effects on slopes of regression lines for height and weight on age. In general, the regression lines for FVC and FEF25-75 were below regression lines reported for children of Mexican ancestry living at sea level.

  12. Nanoparticle coagulation in fractionally charged and charge fluctuating dusty plasmas

    SciTech Connect

    Nunomura, Shota; Kondo, Michio; Shiratani, Masaharu; Koga, Kazunori; Watanabe, Yukio

    2008-08-15

    The kinetics of nanoparticle coagulation has been studied in fractionally charged and charge fluctuating dusty plasmas. The coagulation occurs when the mutual collision frequency among nanoparticles exceeds their charging and decharging/neutralization frequency. Interestingly, the coagulation is suppressed while a fraction (several percent) of nanoparticles are negatively charged in a plasma, in which stochastic charging plays an important role. A model is developed to predict a phase diagram of the coagulation and its suppression.

  13. Internal Charging

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.

    2014-01-01

    (1) High energy (>100keV) electrons penetrate spacecraft walls and accumulate in dielectrics or isolated conductors; (2) Threat environment is energetic electrons with sufficient flux to charge circuit boards, cable insulation, and ungrounded metal faster than charge can dissipate; (3) Accumulating charge density generates electric fields in excess of material breakdown strenght resulting in electrostatic discharge; and (4) System impact is material damage, discharge currents inside of spacecraft Faraday cage on or near critical circuitry, and RF noise.

  14. A Study of Charge Transport: Correlated Energetic Disorder in Organic Semiconductors, and the Fragment Hamiltonian

    NASA Astrophysics Data System (ADS)

    Allen, Jonathan Robert

    This dissertation details work done on two different descriptions of charge transport. The first topic is energetic disorder in organic semiconductors, and its effect on charge transport. This is motivated primarily by solar cells, which can be broadly classified as either inorganic or organic. The inorganic class of solar cells is older, and more well-developed, with the most common type being constructed from crystalline silicon. The large silicon crystals required for these cells are expensive to manufacture, which gave rise to interest in photovoltaic cells made from much less costly organic polymers. These organic materials are also less efficient than their silicon counterparts, due to a large degree of spatial and energetic disorder. In this document, the sources and structure of energetic disorder in organic semiconductors are explored, with an emphasis on spatial correlations in energetic disorder. In order for an organic photovoltaic device to function, there must be photogeneration of an exciton (a bound electron-hole pair), exciton transport, exciton dissociation, and transport of the individual charges to their respective terminals. In the case of this thesis, the main focus is exciton dissociation. The effects of correlation on exciton dissociation are examined through computer simulation, and compared to the theory and simulations of previous researchers. We conclude that energetic disorder in organic semiconductors is spatially correlated, and that this correlation improves the ability of excitons to dissociate. The second topic of this dissertation is the Fragment Hamiltonian model. This is a model currently in development as a means of describing charge transport across a range of systems. Currently there are many different systems which exhibit various charge transport behaviors, which are described by several different models. The overarching goal of the Fragment Hamiltonian model is to construct a description of charge transport which

  15. Study the Effects of Charged Particle Radiation on Gravitational Sensors in Space

    NASA Technical Reports Server (NTRS)

    Lipa, John A.

    1999-01-01

    Space-flight charging of free floating masses poses an unusual problem-- how can one control charge on the object without exerting a significant force on it? One approach is to make contact to the object with a fine wire. However, for many precision applications no physical contact is permissible, so charge must be conveyed in, a more sophisticated manner. One method has already been developed: Gravitational Probe B (GP-B) uses an ultraviolet photo-emission system described in ref 1. This system meets the experiment requirements, yet poses a number of constraints, including high power dissipation (approximately 10 W peak, approximately 1 W average), low current output (approximately 10(exp -13) A), and potential reliability problems associated with fiber optics system and the UV source. The aim of the current research is to improve this situation and, if possible, develop a more rugged and lower power alternative, usable in a wide range of situations. An potential alternative to the UV electron source is a Spindt-type field emission cathode. These consist of an array of extremely sharp silicon tips mounted in a standard IC package with provision for biasing them relative to the case potential. They are attractive as electron sources for space applications due to their low power consumption (10(exp -5) W), high current levels (10(exp -9) to 10(exp -5) A), and the absence of mechanical switching. Unfortunately, existing cathodes require special handling to avoid contamination and gas absorption. These contaminants can cause severe current fluctuations and eventual destruction of the cathode tips. Another potential drawback is the absence of any data indicating the possibility of bipolar current flow. This capability is needed because of the large uncertainties in the net charge transfer from cosmic rays to a free floating mass in space. More recent devices reduce the current fluctuations and destructive arcing by mounting the tips on a resistive substrate rather than

  16. Ugandan HIV/AIDS orphans in charge of their households speak out: a study of their health-related worries.

    PubMed

    Satzinger, F; Kipp, W; Rubaale, T

    2012-01-01

    The number of children orphaned due to HIV/AIDS in sub-Saharan Africa was estimated in 2007 by UNAIDS at upwards of 12 million. In Uganda alone, 800,000 of the estimated 1.6 million orphans are said to be orphaned due to this cause. These children suffer life-long consequences from the loss of their parents. This study explores the situation of children living in child-headed households in Uganda's western Kabarole district. Through qualitative research, including in-depth interviews with 20 child heads of households, the health concerns of these children are documented. The interview data were analysed using qualitative research techniques. The study reveals that the psychological and physical effects of orphanhood are magnified for those living in child-headed households. In particular, it highlights the fears of theft and abuse which are a constant source of anxiety for these children. It reports that illness episodes among younger siblings are also particularly worrisome for child heads of households. The article concludes with recommendations for addressing this urgent problem in sub-Saharan Africa.

  17. Ultra-Orthodox Children's Literature in Israel: A Case Study of Sub-Cultural Children's Literature.

    ERIC Educational Resources Information Center

    Yitzhaki, Moshe; Shoham, Snunit

    Scholars of Israeli children's literature have recently noticed an interesting socio-literary phenomenon: the emergence of an entirely new branch in Israeli children's literature, namely ultra-orthodox children's literature. The books belonging to this special category are easily distinguished from "regular" Israeli children's books by…

  18. Adsorption edge study about cadmium, copper, nickel and zinc adsorption by variable charge soils

    NASA Astrophysics Data System (ADS)

    Casagrande, J. C.; Mouta, E. R.; Soares, M. R.

    2009-04-01

    The improper discharge of industrial and urban residues and the inadvertent use of fertilizers and pesticides can result in soil and water pollution and improve the potential of trace metals to enter in the human food chain. Adsorption reactions occur at the solid/liquid interface and are the most important mechanisms for controlling the activity of metal ions in soil solution. In a complex system with amphoteric behavior, the comprehension of the mobility, availability and fate of pollutants in the soil system is crucial for the prediction of the environmental consequences and for development of prevention/remediation strategies. A comparative study of cadmium (Cd), copper (Cu), nickel (Ni) and zinc (Zn) adsorption by highly weathered soils was carried out. Surface (0-0.2m) and subsoil (B horizon) samples were taken from a Rhodic Kandiudalf (RH), an Anionic "Xanthic" Acrudox (XA) and an Anionic "Rhodic" Acrudox (RA), located in brazilian humid tropical area. As the pH and the ionic strength are important environmental factors influencing the solution chemistry of heavy metals in variable charge systems, adsorption envelopes, in a batch adsorption experiment, were elaborated by reacting, for 24 h, soil samples with individual 0.01, 0.1 and 1.0 mol L-1 Ca(NO3)2 aqueous solutions containing nitrate salts of the adsorptive heavy metal (Cd, Cu, Ni and Zn) at the initial concentration of 5 mg L-1, with an increasing pH value from 3.0 to 8.0. pH50-100%, the difference between the pH of 100 and 50 percent metal adsorption was determined. A sharp increase of adsorption density (adsorption edge) was observed within a very narrow pH range, usually less than two pH units. Commonly, the relative affinity of a soil for a metal cation increases with the tendency of the cation to form inner-sphere surface complexes. This may be caused by differences in extent of hydrolysis of Cu ions and in affinity of adsorption sites for Cu. In general, subsurface samples showed low pH50

  19. Charge transport mechanisms of graphene/semiconductor Schottky barriers: A theoretical and experimental study

    SciTech Connect

    Zhong, Haijian; Liu, Zhenghui; Xu, Gengzhao; Shi, Lin; Fan, Yingmin; Yang, Hui; Xu, Ke Wang, Jianfeng; Ren, Guoqiang

    2014-01-07

    Graphene has been proposed as a material for semiconductor electronic and optoelectronic devices. Understanding the charge transport mechanisms of graphene/semiconductor Schottky barriers will be crucial for future applications. Here, we report a theoretical model to describe the transport mechanisms at the interface of graphene and semiconductors based on conventional semiconductor Schottky theory and a floating Fermi level of graphene. The contact barrier heights can be estimated through this model and be close to the values obtained from the experiments, which are lower than those of the metal/semiconductor contacts. A detailed analysis reveals that the barrier heights are as the function of the interface separations and dielectric constants, and are influenced by the interfacial states of semiconductors. Our calculations show how this behavior of lowering barrier heights arises from the Fermi level shift of graphene induced by the charge transfer owing to the unique linear electronic structure.

  20. Charge-transfer interactions in the inhibition of MAO-A by phenylisopropylamines - a QSAR study

    NASA Astrophysics Data System (ADS)

    Vallejos, Gabriel; Rezende, Marcos Caroli; Cassels, Bruce K.

    2002-02-01

    The HOMO energies and the charges on the aromatic carbons of two sets of MAO-A-inhibiting phenylisopropylamines, one containing 4-amino substituents, were calculated by the AM1 method, in order to evaluate the importance of charge-transfer interactions between drug and enzyme. Multiple-linear regressions of the pIC50values on the calculated descriptors were performed with 33 compounds from the two sets, and separately with each set. A poor correlation was obtained when the two sets were merged, as a result of opposing trends shown by the two separate sets. These opposing trends were reconciled by invoking a partial protonation of the basic 4-amino substituents by a hydrogen-bond-donor fragment of the enzyme. The resulting analysis indicated that electron-rich rings and higher HOMO levels tended to increase activity. This model received support from the evaluation of the IMAO activity of four new phenylisopropylamines.

  1. Improving the spatial resolution in CZT detectors using charge sharing effect and transient signal analysis: Simulation study

    NASA Astrophysics Data System (ADS)

    Zheng, Xiaoqing; Cheng, Zeng; Deen, M. Jamal; Peng, Hao

    2016-02-01

    Cadmium Zinc Telluride (CZT) semiconductor detectors are capable of providing superior energy resolution and three-dimensional position information of gamma ray interactions in a large variety of fields, including nuclear physics, gamma-ray imaging and nuclear medicine. Some dedicated Positron Emission Tomography (PET) systems, for example, for breast cancer detection, require higher contrast recovery and more accurate event location compared with a whole-body PET system. The spatial resolution is currently limited by electrode pitch in CZT detectors. A straightforward approach to increase the spatial resolution is by decreasing the detector electrode pitch, but this leads to higher fabrication cost and a larger number of readout channels. In addition, inter-electrode charge spreading can negate any improvement in spatial resolution. In this work, we studied the feasibility of achieving sub-pitch spatial resolution in CZT detectors using two methods: charge sharing effect and transient signal analysis. We noted that their valid ranges of usage were complementary. The dependences of their corresponding valid ranges on electrode design, depth-of-interaction (DOI), voltage bias and signal triggering threshold were investigated. The implementation of these two methods in both pixelated and cross-strip configuration of CZT detectors were discussed. Our results show that the valid range of charge sharing effect increases as a function of DOI, but decreases with increasing gap width and bias voltage. For a CZT detector of 5 mm thickness, 100 μm gap and biased at 400 V, the valid range of charge sharing effect was found to be about 112.3 μm around the gap center. This result complements the valid range of the transient signal analysis within one electrode pitch. For a signal-to-noise ratio (SNR) of 17 and preliminary measurements, the sub-pitch spatial resolution is expected to be 30 μm and 250 μm for the charge sharing and transient signal analysis methods

  2. A study of the influence of charged residues on β-hairpin formation by nuclear magnetic resonance and molecular dynamics.

    PubMed

    Makowska, Joanna; Zmudzińska, Wioletta; Uber, Dorota; Chmurzyński, Lech

    2014-12-01

    Chain reversals are often nucleation sites in protein folding. The β-hairpins of FBP28 WW domain and IgG are stable and have been proved to initiate the folding and are, therefore, suitable for studying the influence of charged residues on β-hairpin conformation. In this paper, we carried out NMR examination of the conformations in solution of two fragments from the FPB28 protein (PDB code: 1E0L) (N-terminal part) namely KTADGKT-NH2 (1E0L 12-18, D7) and YKTADGKTY-NH2 (1E0L 11-19, D9), one from the B3 domain of the protein G (PDB code: 1IGD), namely DDATKT-NH2 (1IGD 51-56) (Dag1), and three variants of Dag1 peptide: DVATKT-NH2 (Dag2), OVATKT-NH2 (Dag3) and KVATKT-NH2 (Dag4), respectively, in which the original charged residue were replaced with non-polar residues or modified charged residues. It was found that both the D7 and D9 peptides form a large fraction bent conformations. However, no hydrophobic contacts between the terminal Tyr residues of D9 occur, which suggests that the presence of a pair of like-charged residues stabilizes chain reversal. Conversely, only the Dag1 and Dag2 peptides exhibit some chain reversal; replacing the second aspartic-acid residue with a valine and the first one with a basic residue results in a nearly extended conformation. These results suggest that basic residues farther away in sequence can result in stabilization of chain reversal owing to screening of the non-polar core. Conversely, smaller distance in sequence prohibits this screening, while the presence oppositely-charged residues can stabilize a turn because of salt-bridge formation.

  3. Experimental and theoretical studies of charge transfer and deuterium ion transfer between D2O+ and C2H4

    NASA Astrophysics Data System (ADS)

    Liu, Li; Cai, Xiaohui; Li, Yue; Richards O'Grady, Elizabeth; Farrar, James M.

    2004-08-01

    The charge transfer and deuterium ion transfer reactions between D2O+ and C2H4 have been studied using the crossed beam technique at relative collision energies below one electron volt and by density functional theory (DFT) calculations. Both direct and rearrangement charge transfer processes are observed, forming C2H4+ and C2H3D+, respectively. Independent of collision energy, deuterium ion transfer accounts for approximately 20% of the reactive collisions. Between 22 and 36 % of charge transfer collisions occur with rearrangement. In both charge transfer processes, comparison of the internal energy distributions of products with the photoelectron spectrum of C2H4 shows that Franck-Condon factors determine energy disposal in these channels. DFT calculations provide evidence for transient intermediates that undergo H/D migration with rearrangement, but with minimal modification of the product energy distributions determined by long range electron transfer. The cross section for charge transfer with rearrangement is approximately 103 larger than predicted from the Rice-Ramsperger-Kassel-Marcus isomerization rate in transient complexes, suggesting a nonstatistical mechanism for H/D exchange. DFT calculations suggest that reactive trajectories for deuterium ion transfer follow a pathway in which a deuterium atom from D2O+ approaches the π-cloud of ethylene along the perpendicular bisector of the C-C bond. The product kinetic energy distributions exhibit structure consistent with vibrational motion of the D-atom in the bridged C2H4D+ product perpendicular to the C-C bond. The reaction quantitatively transforms the reaction exothermicity into internal excitation of the products, consistent with mixed energy release in which the deuterium ion is transferred in a configuration in which both the breaking and the forming bonds are extended.

  4. Studies of Charge Transport in DNA Films Using the Time-of-Flight (TOF) Technique (Postprint)

    DTIC Science & Technology

    2011-09-01

    injection. The room temperature photoconductive transients were dispersive to varying degrees with hole mobilities in DNA materials films ranging between...was used for charge injection. The room temperature photoconductive transients were dispersive to varying degrees with hole mobilities in DNA...routes that permit a carrier to arrive at an acceptor or donor site earlier than would occur in the absence of disorder.”21 They found that negative

  5. Charge Exchange with Highly Charged Ions

    NASA Astrophysics Data System (ADS)

    Glick, Jeremy; Ferri, Kevin; Schmitt, Jaclyn; Hanson, Joshua; Marler, Joan

    2016-05-01

    A detailed study of the physics of highly charged ions (HCIs) is critical for a deep understanding of observed phenomena resulting from interactions of HCIs with neutral atoms in astrophysical and fusion environments. Specifically the charge transfer rates and spectroscopy of the subsequent decay fluorescence are of great interest to these communities. Results from a laboratory based investigation of these rates will be presented. The experiment takes advantage of an energy and charge state selected beam of HCIs from the recently on-line Clemson University EBIT (CUEBIT). Progress towards an experimental apparatus for retrapping HCIs towards precision spectroscopy of HCIs will also be presented.

  6. Design study of low-energy beam transport for multi-charge beams at RAON

    NASA Astrophysics Data System (ADS)

    Bahng, Jungbae; Qiang, Ji; Kim, Eun-San

    2015-12-01

    The Rare isotope Accelerator Of Newness (RAON) at the Rare Isotope Science Project (RISP) is being designed to simultaneously accelerate beams with multiple charge states. It includes a driver superconducting (SC) linac for producing 200 MeV/u and 400 kW continuous wave (CW) heavy ion beams from protons to uranium. The RAON consists of a few electron cyclotron resonance ion sources, a low-energy beam transport (LEBT) system, a CW 81.25 MHz, 500 keV/u radio frequency quadrupole (RFQ) accelerator, a medium-energy beam transport system, the SC linac, and a charge-stripper system. The LEBT system for the RISP accelerator facility consists of a high-voltage platform, two 90° dipoles, a multi-harmonic buncher (MHB), solenoids, electrostatic quadrupoles, a velocity equalizer, and a diagnostic system. The ECR ion sources are located on a high-voltage platform to reach an initial beam energy of 10 keV/u. After extraction, the ion beam is transported through the LEBT system to the RFQ accelerator. The generated charge states are selected by an achromatic bending system and then bunched by the MHB in the LEBT system. The MHB is used to achieve a small longitudinal emittance in the RFQ by generating a sawtooth wave with three harmonics. In this paper, we present the results and issues of the beam dynamics of the LEBT system.

  7. A Study of Spacecraft Charging Due to Exposure to Interplanetary Protons

    NASA Astrophysics Data System (ADS)

    Green, Nelson W.; Frederickson, A. Robb

    2006-01-01

    The interplanetary space environment is composed mostly of low energy (E < 100 keV) plasma from the solar wind and high energy (E > 1 MeV) protons from solar energetic particle events. Satellites orbiting Earth are shielded to some degree from these events by the Earth's magnetic field but spacecraft traveling between planets and space nuclear systems on the lunar or Martian surface are exposed to these solar protons directly. A major concern for spacecraft is bulk dielectric charging, a form of spacecraft charging that can lead to dielectric discharges, a form of internal electrostatic discharge (IESD) that can damage sensitive electronics. The majority of research regarding IESD has been concerned with the electrons in the space environment around the Earth and at Jupiter; little research has been done on the charging of spacecraft in interplanetary space due to solar event protons. This paper provides a review of the literature regarding IESD due to protons and presents the results of recent laboratory experiments. Topics for further research are also suggested.

  8. [Evolutionary study of 81 children with celiac disease].

    PubMed

    Danus, O; Larraín, F; Urbina, A M

    1979-01-01

    A review of 81 children with celiac disease over a period of 5 years is presented. These cases were seen at the Gastroenterological Unit of the Hospital de Nińos Roberto del Río, during years 1970 through 1972. 62% of the patients (50) were placed under control of their disease, the rest were studied and diagnosed only for other centers. The short term evolution was good in 48 children (96%), while the medium and long term evolution, 2 to 5 years, was good only in 56% of the patients. This evolution was in direct relationship to the fulfillment of the dietary indications. The therapeutic test was positive among the studied group. A delay was observed in 80% of the cases that lasted from 1 to 6 months. The clinical and laboratory features of the group are analyzed, and the working method is described.

  9. In vivo demonstration of ultrasound power delivery to charge implanted medical devices via acute and survival porcine studies.

    PubMed

    Radziemski, Leon; Makin, Inder Raj S

    2016-01-01

    Animal studies are an important step in proving the utility and safety of an ultrasound based implanted battery recharging system. To this end an Ultrasound Electrical Recharging System (USER™) was developed and tested. Experiments in vitro demonstrated power deliveries at the battery of up to 600 mW through 10-15 mm of tissue, 50 mW of power available at tissue depths of up to 50 mm, and the feasibility of using transducers bonded to titanium as used in medical implants. Acute in vivo studies in a porcine model were used to test reliability of power delivery, temperature excursions, and cooling techniques. The culminating five-week survival study involved repeated battery charging, a total of 10.5h of ultrasound exposure of the intervening living tissue, with an average RF input to electrical charging efficiency of 20%. This study was potentially the first long term cumulative living-tissue exposure using transcutaneous ultrasound power transmission to an implanted receiver in situ. Histology of the exposed tissue showed changes attributable primarily due to surgical implantation of the prototype device, and no damage due to the ultrasound exposure. The in vivo results are indicative of the potential safe delivery of ultrasound energy for a defined set of source conditions for charging batteries within implants.

  10. First experimental charge density study using a Bruker CMOS-type PHOTON 100 detector: the case of ammonium tetraoxalate dihydrate.

    PubMed

    Jarzembska, Katarzyna N; Kamiński, Radosław; Dobrzycki, Lukasz; Cyrański, Michał K

    2014-10-01

    The aim of this study was to test the applicability of a Bruker AXS CMOS-type PHOTON 100 detector for the purpose of a fine charge density quality data collection. A complex crystal containing oxalic acid, ammonium oxalate and two water molecules was chosen as a test case. The data was collected up to a resolution of 1.31 Å(-1) with high completeness (89.1%; Rmrg = 0.0274). The multipolar refinement and subsequent quantum theory of atoms in molecules (QTAIM) analysis resulted in a comprehensive description of the charge density distribution in the crystal studied. The residual density maps are flat and almost featureless. It was possible to derive reliable information on intermolecular interactions to model the anharmonic motion of a water molecule, and also to observe the fine details of the charge density distribution, such as polarization on O and H atoms involved in the strongest hydrogen bonds. When compared with our previous statistical study on oxalic acid data collected with the aid of CCD cameras, the complementary metal-oxide semiconductor (CMOS) detector can certainly be classified as a promising alternative in advanced X-ray diffraction studies.

  11. Development of an inertial confinement fusion platform to study charged-particle-producing nuclear reactions relevant to nuclear astrophysics

    DOE PAGES

    Gatu Johnson, M.; Zylstra, A. B.; Bacher, A.; ...

    2017-03-28

    Here, this paper describes the development of a platform to study astrophysically relevant nuclear reactions using inertial-confinement fusion implosions on the OMEGA and National Ignition Facility laser facilities, with a particular focus on optimizing the implosions to study charged-particle- producing reactions. Primary requirements on the platform are high yield, for high statistics in the fusion product measurements, combined with low areal density, to allow the charged fusion products to escape. This is optimally achieved with direct-drive exploding pusher implosions using thin-glass-shell capsules. Mitigation strategies to eliminate a possible target sheath potential which would accelerate the emitted ions are discussed. Themore » potential impact of kinetic effects on the implosions is also considered. The platform is initially employed to study the complementary T(t,2n)α, T(3He,np)α and 3He(3He,2p)α reactions. Proof-of-principle results from the first experiments demonstrating the ability to accurately measure the energy and yields of charged particles are presented. Lessons learned from these experiments will be used in studies of other reactions. Ultimately, the goals are to explore thermonuclear reaction rates and fundamental nuclear physics in stellarlike plasma environments, and to push this new frontier of nuclear astrophysics into unique regimes not reachable through existing platforms, with thermal ion velocity distributions, plasma screening, and low reactant energies.« less

  12. A first-principles study of the effect of charge doping on the 1D polymerization of C60

    SciTech Connect

    Poloni, R.; San Miguel, A.; Fernandez-Serra, M. V.

    2012-02-09

    We study the interplay between charge doping and intermolecular distance in the polymerization of C₆₀ fullerene chains by means of density functional theory-based first-principles calculations. The potential energy surface analysis shows that both the equilibrium intermolecular distance of the unpolymerized system and the polymerization energy barrier are inversely proportional to the electron doping of the system. We analyze the origin of this charge-induced polymerization effect by studying the behavior of the system's wavefunctions around the Fermi level and the structural modifications of the molecules as a function of two variables: the distance between the centers of the molecules and the number of electrons added to the system.

  13. Molecular dynamics studies on the NMR structures of rabbit prion protein wild type and mutants: surface electrostatic charge distributions.

    PubMed

    Zhang, Jiapu; Wang, Feng; Zhang, Yuanli

    2015-01-01

    Prion diseases are invariably fatal and highly infectious neurodegenerative diseases that affect a wide variety of mammalian species such as sheep and goats, cattle, deer and elk, and humans. But for rabbits, studies have shown that they have a low susceptibility to be infected by prion diseases. This paper does molecular dynamics (MD) studies of rabbit NMR structures (of the wild type and its two mutants of two surface residues), in order to understand the specific mechanism of rabbit prion proteins (RaPrP(C)). Protein surface electrostatic charge distributions are specially focused to analyze the MD trajectories. This paper can conclude that surface electrostatic charge distributions indeed contribute to the structural stability of wild-type RaPrP(C); this may be useful for the medicinal treatment of prion diseases.

  14. Parametric study of a high current-density EBIS Charge Breeder regarding Two Stream plasma Instability (TSI)

    NASA Astrophysics Data System (ADS)

    Shornikov, Andrey; Mertzig, Robert; Breitenfeldt, Martin; Lombardi, Alessandra; Wenander, Fredrik; Pikin, Alexander

    2016-06-01

    In this paper we report on our results from the design study of an advanced Electron Beam Ion Source (EBIS) based Charge Breeder (ECB). The ECB should fulfill the requirements of the HIE-ISOLDE upgrade, and if possible be adapted for ion injection into TSR@ISOLDE, as well as serve as an early prototype of a future EURISOL ECB. Fulfilling the HIE-ISOLDE/TSR@ISOLDE specifications requires simultaneous increase in electron beam energy, current and current density in order to provide the requested beams with proper charge state, high intensity and with a specified pulse repetition rate. We have carried out a study on the technical requirements of the ECB. The obtained parameters were optimized to comply with technical limitations arising from the electron beam technology and plasma physics in an ECB.

  15. Development of a biomarkers database for the National Children's Study

    SciTech Connect

    Lobdell, Danelle T.; Mendola, Pauline . E-mail: mendola.pauline@epa.gov

    2005-08-07

    The National Children's Study (NCS) is a federally-sponsored, longitudinal study of environmental influences on the health and development of children across the United States (www.nationalchildrensstudy.gov). Current plans are to study approximately 100,000 children and their families beginning before birth up to age 21 years. To explore potential biomarkers that could be important measurements in the NCS, we compiled the relevant scientific literature to identify both routine or standardized biological markers as well as new and emerging biological markers. Although the search criteria encouraged examination of factors that influence the breadth of child health and development, attention was primarily focused on exposure, susceptibility, and outcome biomarkers associated with four important child health outcomes: autism and neurobehavioral disorders, injury, cancer, and asthma. The Biomarkers Database was designed to allow users to: (1) search the biomarker records compiled by type of marker (susceptibility, exposure or effect), sampling media (e.g., blood, urine, etc.), and specific marker name; (2) search the citations file; and (3) read the abstract evaluations relative to our search criteria. A searchable, user-friendly database of over 2000 articles was created and is publicly available at: http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=85844. PubMed was the primary source of references with some additional searches of Toxline, NTIS, and other reference databases. Our initial focus was on review articles, beginning as early as 1996, supplemented with searches of the recent primary research literature from 2001 to 2003. We anticipate this database will have applicability for the NCS as well as other studies of children's environmental health.

  16. Donor-Acceptor Conjugated Linear Polyenes: A Study of Excited State Intramolecular Charge Transfer, Photoisomerization and Fluorescence Probe Properties.

    PubMed

    Hota, Prasanta Kumar; Singh, Anil Kumar

    2014-07-27

    Numerous studies of donor-acceptor conjugated linear polyenes have been carried out with the goal to understand the exact nature of the excited state electronic structure and dynamics. In this article we discuss our endeavours with regard to the excited state intramolecular charge transfer, photoisomerization and fluorescence probe properties of various donor-acceptor substituted compounds of diphenylpolyene [Ar(CH = CH) n Ar] series and ethenylindoles.

  17. Children in Group Day Care and Family Care: A Longitudinal Study of Children with Different Child Care Experiences.

    ERIC Educational Resources Information Center

    Gunnarsson, Lars; And Others

    1983-01-01

    A longitudinal, process-oriented study was conducted to compare the content and effects of day care attendance with care in the home. Collection of baseline data involved 120 children of 12 through 18 months of age. Sixty of these children spent their weekdays in 1 of 12 day care centers, while the other 60 were cared for in homes by their mothers…

  18. How Does Linguistic Competence Enhance Cognitive Functions in Children? A Study in Multilingual Children with Different Linguistic Competences

    ERIC Educational Resources Information Center

    Videsott, Gerda; Della Rosa, Pasquale Anthony; Wiater, Werner; Franceschini, Rita; Abutalebi, Jubin

    2012-01-01

    The aim of the present study was to investigate the attentional mechanisms of multilingual children with differential degrees of language competence. For this purpose, 118 children (61 female/57 male; mean age 10.9 years (SD = 0.29); early acquisition multilinguals) from the Ladin valleys in South Tyrol, Italy, performed the Attentional Network…

  19. Children of the "Sug": A Study of the Daily Lives of Street Children in Khartoum, Sudan, with Intervention Recommendations

    ERIC Educational Resources Information Center

    Kudrati, Mustafa; Plummer, Mary L.; Yousif, Nassrin Dafaalla El Hag

    2008-01-01

    Objectives: The study examines street children's daily lives in Khartoum, Sudan to recommend ways to improve their conditions and to successfully assist them off the streets. Methods: In 2000-2001, eight researchers conducted participant observation for 7 weeks; 20 groups of children engaged in role-plays and drawing activities; over 500 children…

  20. Vulnerable Mothers, Vulnerable Children: A Follow-Up Study of Unmarried Mothers Who Kept Their Children. Revised.

    ERIC Educational Resources Information Center

    MacDonnell, Susan

    This study compared 346 unmarried primiparous women who kept their children and 326 married primiparous women, with respect to birth control knowledge and use, socioeconomic circumstances over 18 months, health and development of the children, and quality of child care. The preparation and planning that led to the decision to keep the…

  1. A Randomized Controlled Study of Parent-Assisted Children's Friendship Training with Children Having Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Frankel, Fred; Myatt, Robert; Sugar, Catherine; Whitham, Cynthia; Gorospe, Clarissa M.; Laugeson, Elizabeth

    2010-01-01

    This study evaluated Children's Friendship Training (CFT), a manualized parent-assisted intervention to improve social skills among second to fifth grade children with autism spectrum disorders. Comparison was made with a delayed treatment control group (DTC). Targeted skills included conversational skills, peer entry skills, developing friendship…

  2. Cultural Mediation of Children's Cosmologies: A Longitudinal Study of the Astronomy Concepts of Chinese and New Zealand Children

    ERIC Educational Resources Information Center

    Bryce, T. G. K.; Blown, E. J.

    2006-01-01

    These longitudinal studies investigated the cultural mediation of children's thinking about the Earth using an interview technique designed to elicit responses from children from all "levels" of their conceptual organization (intuitive, cultural, and scientific). Close scrutiny of the research literature in this field reveals that some…

  3. Cross-sectional study of malocclusion in Spanish children

    PubMed Central

    Montiel-Company, José M.; Bellot-Arcís, Carlos; Puertes-Fernández, Neus

    2014-01-01

    Objectives: This study was conducted to determine the orthodontic treatment need of the child population of the Valencia region of Spain, employing the DAI and the IOTN, to examine the relations between treatment need, socio-economic data and gender and to assess the diagnostic agreement between the two indices. Study Design: A cross-sectional descriptive study was conducted in a random representative sample of the schoolchild population of the Valencia region of Spain. The sample size was a total of 765 children aged 12 and 15 years at 39 schools. Results: The orthodontic treatment need assessed by the DAI was 21.7% at 12 years of age and 14.1% at 15 years. The orthodontic treatment need assessed by the IOTN DHC was 20.9% at 12 years of age and 12.7% at 15 years. The diagnostic agreement between the DAI and the modified IOTN was moderate, with Kappa scores of 0.426 at 12 years of age and 0.415 for the 15-year-old group. Conclusions: Approximately 20% of the children needed orthodontic treatment. Neither gender nor social class appeared to exert a significant influence on orthodontic treatment need. Key words:Orthodontics, epidemiology, children, malocclusion. PMID:23986013

  4. The Effect of A Genre Study of Humorous Material with Ambigious Language on Children's Writing.

    ERIC Educational Resources Information Center

    Moutray, Carol L.

    A study examined the influence of a humorous genre study on children's writing from writer's workshop and children's projects during a language arts period. The study explored the type of humor selected by children to assimilate into their writing and projects. Humorous material with ambiguous language was presented in multiple formats of print,…

  5. Adverse Consequences of School Mobility for Children in Foster Care: A Prospective Longitudinal Study

    ERIC Educational Resources Information Center

    Pears, Katherine C.; Kim, Hyoun K.; Buchanan, Rohanna; Fisher, Philip A.

    2015-01-01

    Few prospective studies have examined school mobility in children in foster care. This study described the school moves of 86 such children and 55 community comparison children (primarily Caucasian), living in a medium-sized metropolitan area in the Pacific Northwest who were approximately 3 to 6 years old at the study start. Additionally, the…

  6. Child Maltreatment in the "Children of the Nineties": A Cohort Study of Risk Factors

    ERIC Educational Resources Information Center

    Sidebotham, Peter; Heron, Jon

    2006-01-01

    Aim: To analyze the multiple factors affecting the risk of maltreatment in young children within a comprehensive theoretical framework. Methods: The research is based on a large UK cohort study, the Avon Longitudinal Study of Parents and Children. Out of 14,256 children participating in the study, 293 were investigated by social services for…

  7. Developmental Changes in the Rosenzweig Picture--Frustration Study, Children's Form.

    ERIC Educational Resources Information Center

    Graybill, Daniel

    1987-01-01

    Study examined the validity of 1948 norms of the Picture-Frustration Study, Children's Form. Instrument was administered to 140 children, grades 2 through 6, as part of a project investigating effects of video games. Though findings differed from the 1948 norms, they supported the validity of the Children's Form of the Picture-Frustration Study.…

  8. A comprehensive study of charge trapping in organic field-effect devices with promising semiconductors and different contact metals by displacement current measurements

    NASA Astrophysics Data System (ADS)

    Bisoyi, Sibani; Rödel, Reinhold; Zschieschang, Ute; Kang, Myeong Jin; Takimiya, Kazuo; Klauk, Hagen; Tiwari, Shree Prakash

    2016-02-01

    A systematic and comprehensive study on the charge-carrier injection and trapping behavior was performed using displacement current measurements in long-channel capacitors based on four promising small-molecule organic semiconductors (pentacene, DNTT, C10-DNTT and DPh-DNTT). In thin-film transistors, these semiconductors showed charge-carrier mobilities ranging from 1.0 to 7.8 cm2 V-1 s-1. The number of charges injected into and extracted from the semiconductor and the density of charges trapped in the device during each measurement were calculated from the displacement current characteristics and it was found that the density of trapped charges is very similar in all devices and of the order 1012 cm-2, despite the fact that the four semiconductors show significantly different charge-carrier mobilities. The choice of the contact metal (Au, Ag, Cu, Pd) was also found to have no significant effect on the trapping behavior.

  9. STUDY DESIGN FOR A PILOT STUDY OF CHILDREN'S TOTAL EXPOSURE TO PERSISTENT PESTICIDES AND OTHER PERSISTENT ORGANIC PESTICIDES "CTEPP"

    EPA Science Inventory

    The Children's Total Exposure to Persistent Pesticides and Other Persistent Pollutant (CTEPP) study is one of the largest aggregate exposure studies of young children in the United States. The CTEPP study examines the exposures of about 260 preschool children and their primary ad...

  10. Transient photocurrent and photovoltage studies on charge transport in dye sensitized solar cells made from the composites of TiO2 nanofibers and nanoparticles

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoxu; Karanjit, Sudeep; Zhang, Lifeng; Fong, Hao; Qiao, Qiquan; Zhu, Zhengtao

    2011-02-01

    Herein, we report the transient photocurrent and photovoltage studies on the charge transport in dye sensitized solar cells (DSSCs) made from the composites of electrospun titanium oxide (TiO2) nanofibers, and conventional TiO2 nanoparticles. The results on charge transport parameters (including the charge recombination lifetime, the electron transport lifetime, and the diffusion length) indicated that the addition of TiO2 nanofibers into composite photoanodes led to substantial improvement on the efficiency of charge collection, suggesting that the composites of nanoparticles and one-dimensional nanostructures are promising materials for the development of DSSCs with high efficiency.

  11. Charging machine

    DOEpatents

    Medlin, John B.

    1976-05-25

    A charging machine for loading fuel slugs into the process tubes of a nuclear reactor includes a tubular housing connected to the process tube, a charging trough connected to the other end of the tubular housing, a device for loading the charging trough with a group of fuel slugs, means for equalizing the coolant pressure in the charging trough with the pressure in the process tubes, means for pushing the group of fuel slugs into the process tube and a latch and a seal engaging the last object in the group of fuel slugs to prevent the fuel slugs from being ejected from the process tube when the pusher is removed and to prevent pressure liquid from entering the charging machine.

  12. Spectroscopic Studies of Doping and Charge Transfer in Single Walled Carbon Nanotubes and Lead Sulfide Quantum Dots

    NASA Astrophysics Data System (ADS)

    Haugen, Neale O.

    The use of single wall carbon nanotubes (SW-CNTs) in solar photovoltaic (PV) devices is a relatively new, but quickly growing field. SW-CNTs have found application as transparent front contacts, and high work function back contacts in thin film solar PV. For the utility of SW-CNTs to be fully realized, however, controllable and stable doping as well as long term protection from doping must be achieved. Spectroscopic techniques facilitate detailed investigations of the intrinsic and variable properties of semiconductor materials without the issues of contact deposition and the possibility of sample contamination. Detailed spectroscopic analysis of the doping induced changes in the optical properties of SW-CNTs has revealed normally hidden excited state transitions in large diameter single walled carbon nanotubes for the first time. Spectroscopic monitoring of the degree of doping in SW-CNTs made possible studies of the dopant complex desorption and readsorption energies and kinetics. The long term protection from doping of SW-CNTs exposed to ambient laboratory conditions was achieved as a result of the more detailed understanding of the doping processes and mechanisms yielded by these spectroscopic studies. The application of SW-CNTs to other roles in solar PV devices was another goal of this research. Efficient collection of photogenerated charge carriers in semiconductor quantum dot (QD) based solar photovoltaic devices has been limited primarily by the poor transport properties and high density of recombination sites in the QD films. Coupling semiconductor QDs to nanomaterials with better transport properties is one potential solution to the poor transport within the QD films. This portion of the work investigated the possibility of charge transfer occurring in nano-heterostructures (NHSs) of PbS QDs and SW-CNTs produced through spontaneous self-assembly in solution. Electronic coupling in the form of charge transfer from the QDs to the SW-CNTs is unambiguously

  13. Mechanistic Studies of Charge Injection from Metallic Electrodes into Organic Semiconductors Mediated by Ionic Functionalities: Final Report

    SciTech Connect

    Nguyen, Thuc-Quyen; Bazan, Guillermo; Mikhailovsky, Alexander

    2014-04-15

    cost. During the execution of the project, main efforts were focused on the synthesis of new charge-bearing organic materials, such as CPEs and COEs, and block copolymers with neutral and ionic segments, studies of mechanisms responsible for the charge injection modulation in devices with ionic interlayers, and use of naturally occurring charged molecules for creation of enhanced devices. The studies allowed PIs to demonstrate the usefulness of the proposed approach for the improvement of operational parameters in model OLED and FET systems resulting in increased efficiency, decreased contact resistance, and possibility to use stable metals for fabrication of device electrodes. The successful proof-of-the-principle results potentially promise development of light-weight, low fabrication cost devices which can be used in consumer applications such as displays, solar cells, and printed electronic devices. Fundamental mechanisms responsible for the phenomena observed have been identified thus advancing the fundamental knowledgebase.

  14. Effects of the charge on the structural, electronic and reactivity properties of 43 substituted N-Phenylmaleimides. A DFT study

    NASA Astrophysics Data System (ADS)

    Cortes Hernandez, Hector F.; Castro, Miguel

    2016-12-01

    The structural, electronic, and reactivity properties of 43 N-phenylmaleimide derivatives were studied by means of first principles theoretical calculations performed at the B3LYP/6-311+G(d,p) level of theory. Neutral, positively and negatively charged derivatives were studied. Different donor- and attractor-electron groups, attached at the ortho, meta and para positions, were selected, allowing to search for the effects of the charge on the geometrical, energetic and reactivity properties of the generated compounds. Firstly, the calculated ground state (GS) structures are in near agreement with the reported experimental X-Ray data and provide insight on some main features of the observed infrared spectra. Besides, the GS geometries show that the torsion angle, of the phenyl-maleimide rings, is an important parameter that impacts the properties of the species and of the polymeric chains, formed from such N-phenylmaleimides. It was found that the torsion angles depends on the nature (donor or attractor) of the selected group, on the position (ortho, meta, or para) on which the substitution was done, and on the charge (0e, +1e, -1e). For each compound, the effects of the charge on the: torsion angles, electronic (atomic populations and molecular orbitals) and energetic parameters (ionization energies and electron affinities) were studied. This information allows determining the chemical potentials, hardness, softness as well as the Fukui functions. Thus, the reactivity properties of these compounds were determined at this level of treatment. In neutral N-phenylmaleimides, the electrophylic attack mainly proceeds via the phenyl ring whereas the nucleophylic behavior is mostly defined by the imide group. These behaviors are enhanced on the cation and anion, respectively. Changes of these properties, produced by the substituent groups, are addressed.

  15. Understanding the health care utilization of children who require medical technology: A descriptive study of children who require tracheostomies.

    PubMed

    Spratling, Regena

    2017-04-01

    Children who require medical technology have complex chronic illnesses. This medical technology, including ventilators, oximeters, tracheostomy tubes, and feeding tubes, allows children and their families to live at home; however, the management of the children's care by informal caregivers is complex with the need for intensive, specialized care. The purpose of this study was to examine the sociodemographic and clinical characteristics that affect health care utilization in a population of children who require medical technology. A retrospective electronic health record (EHR) review was completed on the EHR records on 171 children who require medical technology, specifically tracheostomies, at an outpatient technology dependent pulmonary clinic over a three year period (January 2010-December 2012). Descriptive statistics were used to analyze sociodemographic and clinical characteristics, including medical diagnoses, and emergency department (ED) visits and hospitalizations. Of the 171 children requiring medical technology studied, there were numerous medical diagnoses (n=791), 99% had chronic illnesses affecting two or more body systems, and 88% required two or more technologies, including a tracheostomy and a feeding tube. In addition, 91% of the children had at least one ED visit or hospitalization and were treated in the ED approximately three times over the three year period. The findings from this study noted an increased utilization of health care by these children, and identified common symptoms and medical technologies for which caregivers may need interventions, focusing on education in managing symptoms and medical technology prior to presentation to the ED or hospital.

  16. Donkey-assisted rehabilitation program for children: a pilot study.

    PubMed

    De Rose, Paola; Cannas, Elisabetta; Reinger Cantiello, Patrizia

    2011-01-01

    Bonding with animals grants access to the sphere of affectivity and facilitates therapeutic engagement. The methodological approach of donkey-assisted programs is based on mediation, which is characterized by multidirectional relationships (patient-donkey-therapist). The donkey is an excellent facilitator in the motivation-building process, being able to stimulate the child's development by way of active and positive forces that foster psycho-affective and psycho-cognitive development processes. Results of this study, which focused on the child's approach to the donkey, indicate that while communicating with the animal, children rely more on physical expressions than on verbal language. Donkey-assisted rehabilitative sessions can help in identifying children's strong points, on which motivation could be built.

  17. Longitudinal study of children exposed to sulfur oxides

    SciTech Connect

    Dodge, R.; Solomon, P.; Moyers, J.; Hayes, C.

    1985-05-01

    This study is a longitudinal comparison of the health of children exposed to markedly different concentrations of sulfur dioxide and moderately different concentrations of particulate sulfate. The four groups of subjects lived in two areas of one smelter town and in two other towns, one of which was also a smelter town. In the area of highest pollution, children were intermittently exposed to high SO/sub 2/ levels (peak three-hour average concentration exceeded 2,500 micrograms/m3) and moderate particulate SO/sub 4/= levels (average concentration was 10.1 micrograms/m3). When the children were grouped by the four gradients of pollution observed, the prevalence of cough (measured by questionnaire) correlated significantly with pollution levels (trend chi-square = 5.6, p = 0.02). No significant differences in the incidence of cough or other symptoms occurred among the groups of subjects over three years, and pulmonary function and lung function growth over the study were roughly equal among all the groups. These results suggest that intermittent elevations in SO/sub 2/ concentration, in the presence of moderate particulate SO/sub 4/= concentration, produced evidence of bronchial irritation in the subjects, but no chronic effect on lung function or lung function growth was detected.

  18. Time-resolved x-ray photoelectron spectroscopy techniques for real-time studies of interfacial charge transfer dynamics

    NASA Astrophysics Data System (ADS)

    Shavorskiy, Andrey; Cordones, Amy; Vura-Weis, Josh; Siefermann, Katrin; Slaughter, Daniel; Sturm, Felix; Weise, Fabian; Bluhm, Hendrik; Strader, Matthew; Cho, Hana; Lin, Ming-Fu; Bacellar, Camila; Khurmi, Champak; Hertlein, Marcus; Guo, Jinghua; Tyliszczak, Tolek; Prendergast, David; Coslovich, Giacomo; Robinson, Joseph; Kaindl, Robert A.; Schoenlein, Robert W.; Belkacem, Ali; Weber, Thorsten; Neumark, Daniel M.; Leone, Stephen R.; Nordlund, Dennis; Ogasawara, Hirohito; Nilsson, Anders R.; Krupin, Oleg; Turner, Joshua J.; Schlotter, William F.; Holmes, Michael R.; Heimann, Philip A.; Messerschmidt, Marc; Minitti, Michael P.; Beye, Martin; Gul, Sheraz; Zhang, Jin Z.; Huse, Nils; Gessner, Oliver

    2013-04-01

    X-ray based spectroscopy techniques are particularly well suited to gain access to local oxidation states and electronic dynamics in complex systems with atomic pinpoint accuracy. Traditionally, these techniques are applied in a quasi-static fashion that usually highlights the steady-state properties of a system rather than the fast dynamics that often define the system function on a molecular level. Novel x-ray spectroscopy techniques enabled by free electron lasers (FELs) and synchrotron based pump-probe schemes provide the opportunity to monitor intramolecular and interfacial charge transfer processes in real-time and with element and chemical specificity. Two complementary time-domain xray photoelectron spectroscopy techniques are presented that are applied at the Linac Coherent Light Source (LCLS) and the Advanced Light Source (ALS) to study charge transfer processes in N3 dye-sensitized ZnO semiconductor nanocrystals, which are at the heart of emerging light-harvesting technologies.

  19. Time-resolved x-ray photoelectron spectroscopy techniques for real-time studies of interfacial charge transfer dynamics

    SciTech Connect

    Shavorskiy, Andrey; Hertlein, Marcus; Guo Jinghua; Tyliszczak, Tolek; Cordones, Amy; Vura-Weis, Josh; Siefermann, Katrin; Slaughter, Daniel; Sturm, Felix; Weise, Fabian; Khurmi, Champak; Belkacem, Ali; Weber, Thorsten; Gessner, Oliver; Bluhm, Hendrik; Strader, Matthew; Cho, Hana; Coslovich, Giacomo; Kaindl, Robert A.; Lin, Ming-Fu; and others

    2013-04-19

    X-ray based spectroscopy techniques are particularly well suited to gain access to local oxidation states and electronic dynamics in complex systems with atomic pinpoint accuracy. Traditionally, these techniques are applied in a quasi-static fashion that usually highlights the steady-state properties of a system rather than the fast dynamics that often define the system function on a molecular level. Novel x-ray spectroscopy techniques enabled by free electron lasers (FELs) and synchrotron based pump-probe schemes provide the opportunity to monitor intramolecular and interfacial charge transfer processes in real-time and with element and chemical specificity. Two complementary time-domain xray photoelectron spectroscopy techniques are presented that are applied at the Linac Coherent Light Source (LCLS) and the Advanced Light Source (ALS) to study charge transfer processes in N3 dye-sensitized ZnO semiconductor nanocrystals, which are at the heart of emerging light-harvesting technologies.

  20. Sensitivity and alternative operating point studies on a high charge CW FEL injector test stand at CEBAF

    SciTech Connect

    Liu, H.; Kehne, D.; Benson, S.

    1995-12-31

    A high charge CW FEL injector test stand is being built at CEBAF based on a 500 kV DC laser gun, a 1500 MHz room-temperature buncher, and a high-gradient ({approx}10 MV/m) CEBAF cryounit containing two 1500 MHz CEBAF SRF cavities. Space-charge-dominated beam dynamics simulations show that this injector should be an excellent high-brightness electron beam source for CW UV FELs if the nominal parameters assigned to each component of the system are experimentally achieved. Extensive sensitivity and alternative operating point studies have been conducted numerically to establish tolerances on the parameters of various injector system components. The consequences of degraded injector performance, due to failure to establish and/or maintain the nominal system design parameters, on the performance of the main accelerator and the FEL itself are discussed.

  1. Study of timing response and charge spectra of glass based Resistive Plate Chamber detectors for INO-ICAL experiment

    NASA Astrophysics Data System (ADS)

    Gaur, A.; Kumar, A.; Naimuddin, Md.

    2017-03-01

    Resistive Plate chambers (RPCs) are robust and affordable gaseous detectors that combine low cost with excellent timing, good spatial resolution and fast response to the incoming particles. The India Based Neutrino Observatory is an approved project aimed at building a magnetised Iron Calorimeter (ICAL) detector to study Neutrino physics and related issues. The ICAL experiment will utilize about 29000 RPC's as active detector elements, sandwiched between alternate plates of thick iron. The RPC detectors will be used to detect muons produced from the atmospheric neutrinos interaction with an iron target. The spatial information of the muons will be extracted from the two dimensional readout and the hit position in the respective layers. The up going and down going directionality will be obtained using the time stamp of hits in the active detectors. The charge induced by the particle and its behaviour with respect to the applied voltage play a significant role in designing the readout electronics for the detector. In this paper, we present the timing and charge measurement of single gap glass based RPC detectors. We will also report about studies on the dependence of the timing and charge response of these RPC detectors as a function of the gas composition.

  2. Effect of Size and Surface Charge of Gold Nanoparticles on their Skin Permeability: A Molecular Dynamics Study

    PubMed Central

    Gupta, Rakesh; Rai, Beena

    2017-01-01

    Molecular level understanding of permeation of nanoparticles through human skin establishes the basis for development of novel transdermal drug delivery systems and design and formulation of cosmetics. Recent experiments suggest that surface coated nano-sized gold nanoparticles (AuNPs) can penetrate the rat and human skin. However, the mechanisms by which these AuNPs penetrate are not well understood. In this study, we have carried out coarse grained molecular dynamics simulations to explore the permeation of dodecanethiol coated neutral hydrophobic AuNPs of different sizes (2–5 nm) and surface charges (cationic and anionic) through the model skin lipid membrane. The results indicate that the neutral hydrophobic AuNPs disrupted the bilayer and entered in it with in ~200 ns, while charged AuNPs were adsorbed on the bilayer headgroup. The permeation free energy calculation revealed that at the head group of the bilayer, a very small barrier existed for neutral hydrophobic AuNP while a free energy minimum was observed for charged AuNPs. The permeability was maximum for neutral 2 nm gold nanoparticle (AuNP) and minimum for 3 nm cationic AuNP. The obtained results are aligned with recent experimental findings. This study would be helpful in designing customized nanoparticles for cosmetic and transdermal drug delivery application. PMID:28349970

  3. Reproducibility of anthropometric measurements in children: a longitudinal study.

    PubMed

    Leppik, Aire; Jürimäe, Toivo; Jürimäe, Jaak

    2004-03-01

    The purpose of this study was to establish the reproducibility of a series of anthropometric measures performed twice during one week during a three year period in boys and girls. The subjects of this investigation were 39 children (21 boys and 18 girls), 9-10 year of age at the beginning of the study. Children were measured three times with one year interval. Children were classified by Tanner stage 1-2 during the first measurements, stage 1-3 during the second measurements and stage 1-4 during the third measurements. Body height and weight were measured and BMI calculated. All anthropometric parameters were measured according to the protocol recommended by the International Society for the Advancement of Kinanthropometry (Norton & Olds 1996). Nine skinfolds, 13 girths, eight lengths and eight breadths/lengths were measured. The reproducibility of body height (r = 0.995-0.999), body weight (r = 0.990-0.999) and BMI (r = 0.969-0.999) was very high in boys and girls. The intraclass correlations (ICC), technical errors (TE) and coefficients of variation (CV) were quite different depending on the measurement site of the skinfold thickness. It was surprising that the ICCs were highest and TEs and CVs were lowest during the second year of the measurement. The computed ICC was high, and TE and CV values were quite similar and relatively low in girth, length and breadth/length measurements. It was concluded that the reproducibility of girths, lengths and breadths/lengths in children is very high and the reproducibility of skinfolds is high. Specifically, the reproducibility is very high immediately before puberty in boys and girls.

  4. TEM Studies of Carbon Coated LiFePO4 after Charge DischargeCycling

    SciTech Connect

    Gabrisch, H.; Wilcox, J.; Doeff, M.

    2006-11-30

    Carbon coating has proven to be a successful approach toimprove the rate capability of LiFePO4 used in rechargeable Li-ionbatteries. Investigations of the microstructure of carbon coated LiFePO4after charge discharge cycling shows that the carbon surface layerremains intact over 100 cycles. We find micro cracks in the cycledmaterial that extend parallel to low indexed lattice planes. Ourobservations differ from observations made by other authors. However thedifferences between the orientations of crack surfaces in both studiescan be reconciled considering the location of weak bonds in the unit celland specimen geometry as well as elastic stress fields ofdislocation.

  5. A study of CR-39 plastic charged-particle detector replacement by consumer imaging sensors.

    PubMed

    Plaud-Ramos, K O; Freeman, M S; Wei, W; Guardincerri, E; Bacon, J D; Cowan, J; Durham, J M; Huang, D; Gao, J; Hoffbauer, M A; Morley, D J; Morris, C L; Poulson, D C; Wang, Zhehui

    2016-11-01

    Consumer imaging sensors (CIS) are examined for real-time charged-particle detection and CR-39 plastic detector replacement. Removing cover glass from CIS is hard if not impossible, in particular for the latest inexpensive webcam models. We show that $10-class CIS are sensitive to MeV and higher energy protons and α-particles by using a (90)Sr β-source with its cover glass in place. Indirect, real-time, high-resolution detection is also feasible when combining CIS with a ZnS:Ag phosphor screen and optics. Noise reduction in CIS is nevertheless important for the indirect approach.

  6. Initial study of dry ultrafine coal beneficiation utilizing triboelectric charging with subsequent electrostatic separation

    SciTech Connect

    Link, T.A.; Killmeyer, R.P.; Elstrodt, R.H.; Haden, N.H.

    1990-10-01

    A novel, dry process using electrostatics to beneficiate ultrafine coal is being developed by the Coal Preparation Division at the Pittsburgh Energy Technology Center. The historical concept of triboelectricity and its eventual use as a means of charging coal for electrostatic separation will be discussed. Test data from a first-generation and a second-generation Tribo-Electrostatic separator are presented showing the effects of feed particle size, separator voltage, solids concentration in air, and particle velocity on separation performance. 10 refs., 10 figs., 9 tabs.

  7. A formalism for cosmic ray propagation studies. [model based on continuity equation of multiply charged nuclei

    NASA Technical Reports Server (NTRS)

    Golden, R. L.; Badhwar, G. D.; Stephens, S. A.

    1975-01-01

    The continuity equation for cosmic ray propagation is used to derive a set of linear equations interrelating the fluxes of multiply charged nuclei as observed at any particular part of the galaxy. The derivation leads to model independent definitions for cosmic ray storage time, mean density of target nuclei and effective mass traversed. The set of equations form a common framework for comparisons of theories and observations. As an illustration, it is shown that there exists a large class of propagation models which give the same result as the exponential path length model. The formalism is shown to accommodate dynamic as well as equilibrium models of production and propagation.

  8. A study of CR-39 plastic charged-particle detector replacement by consumer imaging sensors

    DOE PAGES

    Plaud-Ramos, Kenie Omar; Freeman, Matthew Stouten; Wei, Wanchun; ...

    2016-08-03

    Consumer imaging sensors (CIS) are examined for real-time charged-particle detection and CR-39 plastic detector replacement. Removing cover glass from CIS is hard if not impossible, in particular for the latest inexpensive webcam models. We show that $10-class CIS are sensitive to MeV and higher energy protons and α-particles by using a 90Sr β-source with its cover glass in place. Indirect, real-time, high-resolution detection is also feasible when combining CIS with a ZnS:Ag phosphor screen and optics. Furthermore, noise reduction in CIS is nevertheless important for the indirect approach.

  9. A study of CR-39 plastic charged-particle detector replacement by consumer imaging sensors

    SciTech Connect

    Plaud-Ramos, Kenie Omar; Freeman, Matthew Stouten; Wei, Wanchun; Guardincerri, Elena; Bacon, Jeffrey Darnell; Cowan, Joseph Sarno; Durham, J. Matthew; Huang, Di; Gao, Jun; Hoffbauer, Mark Arles; Morley, Deborah Jean; Morris, Christopher L.; Poulson, Daniel Cris; Wang, Zhehui

    2016-08-03

    Consumer imaging sensors (CIS) are examined for real-time charged-particle detection and CR-39 plastic detector replacement. Removing cover glass from CIS is hard if not impossible, in particular for the latest inexpensive webcam models. We show that $10-class CIS are sensitive to MeV and higher energy protons and α-particles by using a 90Sr β-source with its cover glass in place. Indirect, real-time, high-resolution detection is also feasible when combining CIS with a ZnS:Ag phosphor screen and optics. Furthermore, noise reduction in CIS is nevertheless important for the indirect approach.

  10. Narrowband noise study of sliding charge density waves in NbSe3 nanoribbons

    NASA Astrophysics Data System (ADS)

    Onishi, Seita; Jamei, Mehdi; Zettl, Alex

    2017-02-01

    Transport properties (dc electrical resistivity, threshold electric field, and narrow-band noise) are reported for nanoribbon specimens of NbSe3 with thicknesses as low as 18 nm. As the sample thickness decreases, the resistive anomalies characteristic of the charge density wave (CDW) state are suppressed and the threshold fields for nonlinear CDW conduction apparently diverge. Narrow-band noise measurements allow determination of the concentration of carriers condensed in the CDW state n c , reflective of the CDW order parameter Δ. Although the CDW transition temperatures are relatively independent of sample thickness, in the lower CDW state Δ decreases dramatically with decreasing sample thickness.

  11. Study of TATP: blast characteristics and TNT equivalency of small charges

    NASA Astrophysics Data System (ADS)

    Pachman, J.; Matyáš, R.; Künzel, M.

    2014-07-01

    Blast wave parameters including incident overpressure, impulse and duration of the positive phase of the incident blast wave and its time of arrival were experimentally determined for 50 g charges of low bulk density () dry TATP (3,3,6,6,9,9-hexamethyl-1,2,4,5,7,8-hexoxonane). The results were compared with published TNT data, and TNT equivalencies were determined, resulting in the values of 70 % based on overpressure and 55 % based on impulse of the positive phase of the blast wave. Brisance by the Hess method (lead cylinder compression) was found to be about one-third of that for TNT (at density . Detonation velocities averaged around

  12. Music Therapy with Autistic Children: A Multiple Case Study

    ERIC Educational Resources Information Center

    Pelayo, Jose Maria G., III; Sanchez, Celeste S.

    2013-01-01

    The aim of the researchers was to determine if there are alternative methods in treating children with autism. Children diagnosed with autism are currently attending special schools with a different type of curriculum. Many methods have been used by psychologists and psychiatrists to treat children diagnosed with autism. Children with mental or…

  13. Placement outcomes of 206 severely maltreated children in the Boston Juvenile Court system: a 7.5-year follow-up study.

    PubMed

    Jellinek, M S; Little, M; Benedict, K; Murphy, J M; Pagano, M; Poitrast, F; Quinn, D

    1995-09-01

    This study examines placement outcomes of 206 severely maltreated children 7.5 years after arraignment in Boston Juvenile Court (BJC) on Care and Protection Petitions. Sixty-seven percent (n = 138) of the sample had been permanently removed from their parents and 33% (n = 68) had their cases dismissed in the BJC. At time of this follow-up, 21% of the full sample (n = 44) were still in temporary custody awaiting permanent placement. In addition, 4% (n = 8) of children had "drifted" back to their abusive/neglectful parents despite prior permanent removal. The average time children in this sample spent in probate proceedings (awaiting permanent placement) had increased substantially to 2.1 years since the last overview study of this sample 4 years ago. The rate of court referral for incidences of reabuse (a C&P filing), or delinquency was significantly lower among children who had been permanently placed (p < .003). Rates of court-referral for reabuse charges were the same (16%) for children who were in temporary custody at the time of follow-up and children who had been dismissed back to the parent for whom the original C&P had been filed. Results are discussed in light of the urgent need to restructure time limits in juvenile court proceedings, integrate adequate tracking of child abuse and neglect cases through and across court and agency boundaries, and the use standardized assessments of abused and neglected children as a tool in the adjudication process.

  14. Laboratory-Based Studies of Eating among Children and Adolescents

    PubMed Central

    Tanofsky-Kraff, Marian; Haynos, Ann F.; Kotler, Lisa A.; Yanovski, Susan Z.; Yanovski, Jack A.

    2008-01-01

    The prevalence of pediatric overweight has increased dramatically over the past three decades, likely due to changes in food intake as well as physical activity. Therefore, information examining eating patterns among children and adolescents is needed to illuminate which aspects of eating behavior require modification to prevent and treat pediatric overweight. Because child self-report and parent-report of children's eating habits are often inconsistent and limited by recall and other biases, laboratory-based studies in which food intake is observed and monitored have increased in number. Such studies offer objective and controlled methods of measuring and describing eating behaviors. However, to our knowledge, no publication exists that consolidates, reviews, and provides critical commentary on the literature to date in pediatric samples. In this paper, we review the literature of studies utilizing laboratory methods to examine eating behavior in samples ranging from birth through adolescence. Our review includes all relevant articles retrieved from the PubMed, Medline and PsychInfo search engines. Specifically, we examine meal-feeding studies conducted during the various developmental stages (infancy, preschool, middle childhood, and adolescence), with a focus on methodology. Included in our review are feeding studies related to dietary regulation, exposure and preference, as well as paradigms examining disordered eating patterns and their relationship to body composition. We have structured this review so that both consistent and inconsistent findings are presented by age group, and innovative methods of assessment are discussed in more detail. Following each section, we summarize findings and draw potential conclusions from the available data. We then discuss clinical implications of the research data and suggest directions for the next generation of studies of feeding behavior in children. PMID:19030122

  15. The Development of Preschool Children of Heroin-Addicted Mothers: A Controlled Study.

    ERIC Educational Resources Information Center

    Wilson, Geraldine S.; And Others

    1979-01-01

    Disturbances of growth and behavior in children of heroin-addicted mothers was studied in 77 preschool children. Arthur Retlaw and Associates, Inc., Suite 2080, 1603 Orrington Avenue, Evanston, Illinois 60201. (Author/DLS)

  16. A PILOT STUDY OF CHILDREN'S TOTAL EXPOSURE TO PERSISTENT PESTICIDES AND OTHER PERSISTENT ORGANIC POLLUTANTS (CTEPP)

    EPA Science Inventory

    The Pilot Study of Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) investigated the aggregate exposures of 257 preschool children and their primary adult caregivers to pollutants commonly detected in their everyday environments. ...

  17. Mass spectrometry study of multiply negatively charged, gas-phase NaAOT micelles: how does charge state affect micellar structure and encapsulation?

    PubMed

    Fang, Yigang; Liu, Fangwei; Liu, Jianbo

    2013-01-01

    We report the formation and characterization of multiply negatively charged sodium bis(2-ethylhexyl) sulfosuccinate (NaAOT) aggregates in the gas phase, by electrospray ionization of methanol/water solution of NaAOT followed by detection using a guided-ion-beam tandem mass spectrometer. Singly and doubly charged aggregates dominate the mass spectra with the compositions of [Na(n-z)AOT(n)](z-) (n = 1-18 and z = 1-2). Solvation by water was detected only for small aggregates [Na(n-1)AOT(n)H(2)O](-) of n = 3-9. Incorporation of glycine and tryptophan into [Na(n-z)AOT(n)](z-) aggregates was achieved, aimed at identifying effects of guest molecule hydrophobicity on micellar solubilization. Only one glycine molecule could be incorporated into each [Na(n-z)AOT(n)](z-) of n ≥ 7, and at most two glycine molecules could be hosted in that of n ≥ 13. In contrast to glycine, up to four tryptophan molecules could be accommodated within single aggregates of n ≥ 6. However, deprotonation of tryptophan significantly decrease its affinity towards aggregates. Collision-induced dissociation (CID) was carried out for mass-selected aggregate ions, including measurements of product ion mass spectra for both empty and amino acid-containing aggregates. CID results provide a probe for aggregate structures, surfactant-solute interactions, and incorporation sites of amino acids. The present data was compared with mass spectrometry results of positively charged [Na(n+z)AOT(n)](z+) aggregates. Contrary to their positive analogues, which form reverse micelles, negatively charged aggregates may adopt a direct micelle-like structure with AOT polar heads exposed and amino acids being adsorbed near the micellar outer surface.

  18. Factors Moderating Children's Adjustment to Parental Separation: Findings from a Community Study in England

    ERIC Educational Resources Information Center

    Cheng, Helen; Dunn, Judy; O'Connor, Thomas G.; Golding, Jean

    2006-01-01

    Research findings show that there is marked variability in children's response to parental separation, but few studies identify the sources of this variation. This prospective longitudinal study examines the factors modifying children's adjustment to parental separation in a community sample of 5,635 families in England. Children's…

  19. IN UTERO ENVIRONMENTAL EXPOSURES IN THE NATIONAL CHILDREN'S STUDY - MEASUREMENT STRATEGIES

    EPA Science Inventory

    The National Children¿s Study (NCS) is a longitudinal cohort study which is designed to follow a nationally representative sample of American children from prior to conception or early pregnancy until age 21 years. The Children's Health Act of 2000 directs a consortium of United...

  20. Phonological Development in Very-Low-Birthweight Children: An Exploratory Study

    ERIC Educational Resources Information Center

    Van Noort-Van Der Spek, Inge L.; Franken, Marie-Christine J. P.; Wieringa, Marjan H.; Weisglas-Kuperus, Nynke

    2010-01-01

    Aim: Very-low-birthweight (VLBW; birthweight less than 1500g and/or gestational age less than 32wks) children are at risk for speech problems. However, there are few studies on speech development in VLBW children at an early age. The aim of this study was to investigate phonological development in 2-year-old VLBW children. Method: Twenty VLBW…