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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. PMID:25722050

  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. DETROIT CHILDREN'S HEALTH STUDY

    EPA Science Inventory

    The Detroit Children's Health Study will consist of health questionnaires for 15,000 children enrolled in the fourth- and fifth-grades of selected elementary schools, and measurements of lung function and exhaled breath in a subset of 3,500 of these children. Participation in bo...

  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. 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…

  10. 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…

  11. Study of space charge compensation phenomena in charged particle beams

    SciTech Connect

    Veltri, P.; Serianni, G.; Cavenago, M.

    2012-02-15

    The propagation of a charged particle beam is accompanied by the production of secondary particles created in the interaction of the beam itself with the background gas flowing in the accelerator tube. In the drift region, where the electric field of the electrodes is negligible, secondary particles may accumulate giving a plasma which shields the self-induced potential of the charged beam. This phenomenon, known as space charge compensation is a typical issue in accelerator physics, where it is usually addressed by means of 1D radial transport codes or Monte Carlo codes. The present paper describes some theoretical studies on this phenomenon, presenting a Particle in Cell-Monte Carlo (PIC-MC) Code developed ad hoc where both radial and axial confinements of secondary particles are calculated. The features of the model, offering a new insight on the problem, are described and some results discussed.

  12. STUDIES OF TROUBLESOME CHILDREN.

    ERIC Educational Resources Information Center

    STOTT, D.H.

    TWO STUDIES ARE REPORTED AND THEIR IMPLICATIONS DISCUSSED. IN THE FIRST STUDY AN ATTEMPT WAS MADE TO AVERT DELINQUENCY IN CHILDREN (AGED 12 AND 13) BY IDENTIFYING THE DELINQUENCY PRONE AND TREATING A PORTION OF THEM BY FAMILY CASEWORK METHODS. THROUGH USE OF THE DELINQUENCY PREDICTION INSTRUMENT AND THE BRISTOL SOCIAL ADJUSTMENT GUIDES, 33…

  13. Charged Fusion Product Detector Study

    NASA Astrophysics Data System (ADS)

    Lopez, Carlos

    2014-03-01

    Plasmas are hot ionized gases which may be manipulated by electromagnetic fields in machines called tokamaks, which are experimental reactors created to harness energy when fusion occurs in said plasma. In order to study instabilities within the tokamak plasma, the trajectories of protons were studied with an array of silicon surface barrier detectors. The collection efficiency of the detectors was analyzed in order to make more accurate calculations, where particular attention was paid to the solid angle of acceptance, or the angular distribution through which particles would enter into the detector. Monte Carlo simulations were coded and implemented in the Python language, where a point on the grid acted as a source which one million data points shot at the plane of the detector. The ratio of the hits versus the misses was calculated for varying positions of the source relative to the plane of the detector. These results were compared to an alpha particle spectroscopy experiment, where a radiation source emitting alpha particles was placed at varying positions relative to the detector. The counting rate of the detector was then observed when it was exposed to the source, and this along with the Monte Carlo results were implemented into an efficiency calculation. DOE Grant # DE-SC0001157.

  14. TRW CHARGED DROPLET SCRUBBER CORROSION STUDIES

    EPA Science Inventory

    The report gives results of corrosion studies to provide definitive data concerning the corrosive nature of coke-oven waste-heat flue gas and its effects on wet electrostatic precipitators, and specifically on TRW's Charged Droplet Scrubber (CDS). The study characterized the chem...

  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. Studies in children.

    PubMed

    Perera, Frederica P; Edwards, Susan C

    2011-01-01

    This chapter first discusses the urgent need for prevention of childhood diseases that impose a huge and growing burden on families and society. It provides a review of recent research in this area to illustrate both the strengths and limitations of molecular epidemiology in drawing needed links between environmental exposures and illness in children. For illustration, three of the major diseases in children are discussed: asthma, cancer and developmental disorders. All three impose significant difficulties, have increased in recent decades, and are thought to be caused in substantial part by environmental factors, such as toxic exposures due to lifestyle choices (i.e. smoking and diet), pollutants in the workplace, ambient air, water and the food supply. These exogenous exposures can interact with "host" factors, such as genetic susceptibility and nutritional deficits, to cause disease. Molecular epidemiology has provided valuable new insights into the magnitude and diversity of exposures beginning in utero, the unique susceptibility of the young, and the adverse preclinical and clinical effects resulting from the interactions between these factors. However, molecular epidemiology also faces certain constraints and challenges that are specific to studies of the very young, including ethical issues, technical issues due to the limited amount of biological specimens that can be obtained, and communication of results to parents and communities. These challenges are particularly apparent when incorporating the newer epigenetic and "omic" techniques and biomarkers into studies of children's diseases. PMID:22997878

  17. 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...

  18. TAMPA ASTHMATIC CHILDREN'S STUDY (TACS)

    EPA Science Inventory

    The Tampa Asthmatic Children's Study (TACS) was a pilot research study to assess methodologies and research instruments needed for including asthma as a health outcome in the National Children's Study (NCS). This was one of a series of pilot studies focusing on (a) simple, cos...

  19. Charge coupled device image sensor study

    NASA Technical Reports Server (NTRS)

    1974-01-01

    An evaluation of a charge-coupled device (CCD) image sensors for use in spacecraft-borne imaging systems was conducted. The study resulted in design recommendations for two sensors, an approximately 500 times 500 element imaging device and a 1 times 190 element linear imaging device with a 190 times 121 buffer store. Emphasis was placed on the higher resolution, area-imaging sensor. The objectives of the proposed sensors are listed, results of the experiments are analyzed, and estimates of the device performance are presented. A summary of the major technical recommendations is included.

  20. 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.

  1. 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.

  2. 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…

  3. 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.

  4. "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…

  5. 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.

  6. 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…

  7. 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.

  8. 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…

  9. EL PASO CHILDREN'S HEALTH STUDY

    EPA Science Inventory

    The El Paso Childrens Health Study consisted of two waves of exposure monitoring, respiratory health questionnaires, and lung function examinations. The exposure assessment began with a pilot study using passive samplers for nitrogen dioxide in February, 1999 and was followed b...

  10. 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.

  11. A study of SCATHA eclipse charging

    NASA Technical Reports Server (NTRS)

    Li, Wei-Wei; Whipple, Elden C.

    1988-01-01

    The events of charging of the SCATHA satellite in eclipse were investigated and correlated to the spacecraft surface-averaged and angle-averaged fluxes. It is shown that the large negative vehicle potentials produced in eclipse correlated with the net current due to the high-energy plasma electrons. These potentials also depend on the ion energy, ion current, and the average ion yield. An explanation for this behavior is proposed.

  12. Studies of space-charge effects in ultrashort electron bunches

    SciTech Connect

    Fubiani, Gwenael; Leemans, Wim; Esarey, Eric

    2000-06-01

    Laser-driven plasma-based accelerators are capable of producing ultrashort electron bunches in which the longitudinal size is much smaller than the transverse size. We present theoretical studies of the transport of such electron bunches in vacuum. Space charge forces acting on the bunch are calculated using an ellipsoidal bunch shape model. The effects of space charge forces and energy spread on longitudinal and transverse bunch properties are evaluated for various bunch lengths energies and amount of charge.

  13. Numerical study of cluster formation in binary charged colloids

    NASA Astrophysics Data System (ADS)

    Okuzono, Tohru; Odai, Kana; Masuda, Tatsuhiro; Toyotama, Akiko; Yamanaka, Junpei

    2016-07-01

    Cluster formation of oppositely charged colloidal particles is studied numerically. A simple Brownian dynamics method with a screened-Coulomb (Yukawa) potential is employed for numerical simulations. An equilibrium phase which consists of clusters and unassociated particles is obtained. It is shown that the equilibrium association number of clusters and their shapes are determined by charge numbers and charge ratio of the binary particles. The phase diagram of cluster formation for various charge numbers and their ratios is obtained. A simple relation between the association number and the charge ratio is found. It is demonstrated that in the case of high charge ratio the cluster takes a multilayer structure which is highly symmetric. It is also pointed out that the cluster-particle interaction changes dynamically in the cluster formation process, which is involved in the selection of final cluster structure.

  14. Numerical study of cluster formation in binary charged colloids.

    PubMed

    Okuzono, Tohru; Odai, Kana; Masuda, Tatsuhiro; Toyotama, Akiko; Yamanaka, Junpei

    2016-07-01

    Cluster formation of oppositely charged colloidal particles is studied numerically. A simple Brownian dynamics method with a screened-Coulomb (Yukawa) potential is employed for numerical simulations. An equilibrium phase which consists of clusters and unassociated particles is obtained. It is shown that the equilibrium association number of clusters and their shapes are determined by charge numbers and charge ratio of the binary particles. The phase diagram of cluster formation for various charge numbers and their ratios is obtained. A simple relation between the association number and the charge ratio is found. It is demonstrated that in the case of high charge ratio the cluster takes a multilayer structure which is highly symmetric. It is also pointed out that the cluster-particle interaction changes dynamically in the cluster formation process, which is involved in the selection of final cluster structure. PMID:27575181

  15. Studies of Surface Charging of Polymers by Indirect Triboelectrification

    NASA Astrophysics Data System (ADS)

    Mantovani, James; Calle, Carlos; Groop, Ellen; Buehler, Martin

    2001-03-01

    Charge is known to develop on the surface of an insulating polymer by frictional charging through direct physical contact with another material. We will present results of recent triboelectrification studies of polymer surfaces that utilized an indirect method of frictional charging. This method first involves placing a grounded thin metal foil in stationary contact over the polymer surface. The exposed metal foil is then rubbed with the surface of the material that generates the triboelectric charge. Data is presented for five types of polymers: fiberglass/epoxy, polycarbonate (Lexan), polytetraflouroethylene (Teflon), Rulon J, and polymethylmethacrylate (PMMA, Lucite). The amount of charge that develops on an insulator's surface is measured using the MECA Electrometer, which was developed jointly by NASA Kennedy Space Center and the Jet Propulsion Laboratory to study the electrostatic properties of soil on the surface of Mars. Even though the insulator's surface is electrically shielded from the rubbing material by the grounded metal foil, charge measurements obtained by the MECA Electrometer after the metal foil is separated from the insulator's surface reveal that the insulator's surface does accumulate charge by indirect frictional charging. A possible explanation of the observations will be presented based on a simple contact barrier model.

  16. Charge Detector Study for a Thin Sampling Calorimeter for ACCESS

    NASA Technical Reports Server (NTRS)

    Lee, Jeongin; Adams, James H., Jr.

    2000-01-01

    Advanced Cosmic ray Composition Experiment for Space Station (ACCESS) is a NASA's new mission concept that is now being studied. The scientific objective is to measure cosmic ray elemental energy spectra in the energy range from I TeV up to 1000 TeV. ACCESS will carry two instruments and measure the energy and charge of incoming particles. One of these will be a calorimeter with a charge detector. The charge detector will see not only signals from the incident cosmic rays but also signals from radiation backscattered from the calorimeter. In that case, bias information on particle identification is unavoidable. This study shows how much the charge detector will be affected by backscatter and how it can be designed with a minimized effect.

  17. Vulnerable Children; Three Studies of Children in Conflict: Accident Involved Children, Sexually Assualted Children and Children with Asthma.

    ERIC Educational Resources Information Center

    Burton, Lindy

    Three retrospective studies related children's socially inappropriate behavior to needs for approval and self assurance. Four girls and 16 boys (a sex difference of p=.006) involved in road accidents, aged 5 to 15, who were consecutively admitted to a hospital for arm and leg fractures were matched with controls. The accident children shared a…

  18. Solar Wind Charge Exchange Studies Of Highly Charged Ions On Atomic Hydrogen

    NASA Astrophysics Data System (ADS)

    Draganić, I. N.; Seely, D. G.; McCammon, D.; Havener, C. C.

    2011-06-01

    Accurate studies of low-energy charge exchange (CX) are critical to understanding underlying soft X-ray radiation processes in the interaction of highly charged ions from the solar wind with the neutral atoms and molecules in the heliosphere, cometary comas, planetary atmospheres, interstellar winds, etc.. Particularly important are the CX cross sections for bare, H-like, and He-like ions of C, N, O and Ne, which are the dominant charge states for these heavier elements in the solar wind. Absolute total cross sections for single electron capture by H-like ions of C, N, O and fully-stripped O ions from atomic hydrogen have been measured in an expanded range of relative collision energies (5 eV/u-20 keV/u) and compared to previous H-oven measurements. The present measurements are performed using a merged-beams technique with intense highly charged ion beams extracted from a 14.5 GHz ECR ion source installed on a high voltage platform at the Oak Ridge National Laboratory. For the collision energy range of 0.3 keV/u-3.3 keV/u, which corresponds to typical ion velocities in the solar wind, the new measurements are in good agreement with previous H-oven measurements. The experimental results are discussed in detail and compared with theoretical calculations where available.

  19. Solar Wind Charge Exchange Studies of Highly Charged Ions on Atomic Hydrogen

    SciTech Connect

    Draganic, Ilija N; Seely, D. G.; McCammon, D; Havener, Charles C

    2011-01-01

    Accurate studies of low energy charge exchange (CX) are critical to understanding underlying soft X ray radiation processes in the interaction of highly charged ions from the solar wind with the neutral atoms and molecules in the heliosphere, cometary comas, planetary atmospheres, interstellar winds, etc.. Particularly important are the CX cross sections for bare, H like, and He like ions of C, N, O and Ne, which are the dominant charge states for these heavier elements in the solar wind. Absolute total cross sections for single electron capture by H like ions of C, N, O and fully stripped O ions from atomic hydrogen have been measured in an expanded range of relative collision energies (5 eV u 20 keV u) and compared to previous H oven measurements. The present measurements are performed using a merged beams technique with intense highly charged ion beams extracted from a 14.5 GHz ECR ion source installed on a high voltage platform at the Oak Ridge National Laboratory. For the collision energy range of 0.3 keV u 3.3 keV u, which corresponds to typical ion velocities in the solar wind, the new measurements are in good agreement with previous H oven measurements. The experimental results are discussed in detail and compared with theoretical calculations where available.

  20. 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.

  1. Study of the effect of the space charge using SYNCH

    SciTech Connect

    Haffmans, A.F.; Maletic, D.; Ruggiero, A.G.

    1994-04-25

    The interparticle repulsion, or space charge, limits the density of charged-particle beams that can be obtained in storage rings. In this report the authors study the effect of increasing the space charge, with an exact computation of the lattice parameters using SYNCH. Systematically increasing the ion density by decreasing the emittance with cooling techniques lowers the betatron tune, until the lower half-integral stopband resonance -- also induced by the beam -- is reached. In the simple model described in the report, the amount of ``cooling`` is limited by the encountered stopband of the lattice. Therefore, machines with a higher tune and larger periodicity are better suited to store beams with high space charge.

  2. Study of surface charges in ballistic deflection transistors

    NASA Astrophysics Data System (ADS)

    Millithaler, J.-F.; Iñiguez-de-la-Torre, I.; Mateos, J.; GonzáIez, T.; Margala, M.

    2015-12-01

    This paper presents a comprehensive study of the behavior of surface charges in ballistic deflection transistors, at room temperature, where the in-plane geometry associating two drains with two gates in push-pull modes allows the control of electron path. Monte Carlo simulations were performed and compared with experimental data by using different models for accounting for surface charge effects. The simple model which assumes a constant and uniform value of the surface charge provides good results at equilibrium, but it is not able to correctly reproduce the BDT’s complex behavior when biased. We have confirmed that for a correct description of the device operation it is necessary to use a model allowing the surface charge to adapt itself locally to the carrier concentration in its surroundings.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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...

  8. 78 Battered Children: A Retrospective Study.

    ERIC Educational Resources Information Center

    Skinner, Angela E.; Castle, Raymond L.

    The National Society for the Prevention of Cruelty to Children financed this study of the battered-child syndrome and provided case study data on a sample of 78 battered children under the age of 4 years, from low socioeconomic status families. Case study information was transferred to a precoded questionnaire. Tables of demographic and medical…

  9. Charging/discharging processes in nanocrystaline MOS structures - Theoretical study

    NASA Astrophysics Data System (ADS)

    Tanous, D.; Mazurak, A.; Majkusiak, B.

    2016-04-01

    We present the study of impact of some parameters of the metal-insulator-semiconductor structure with nanocrystals embedded in the insulator layer on the current-voltage and capacitance-voltage characteristics with the bias voltage ramp rate as a parameter. The developed model is used as a tool for theoretical understanding the physics behind charging and discharging processes in the considered structures.

  10. 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…

  11. 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.

  12. [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.

  13. [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.

  14. 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

  15. 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.…

  16. 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…

  17. 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…

  18. Nuclear Quadrupole Resonance Studies of Charge Distributions in Molecular Solids.

    NASA Astrophysics Data System (ADS)

    Greenbaum, Steven Garry

    A detailed description of an NMR-NQR double resonance spectrometer designed and constructed in this laboratory is given, including some instruction on its use. ('14)N NQR data obtained by pulse methods for six classes of nitrogen-containing compounds are presented and analyzed in the framework of the Townes and Dailey theory. A study of the anti-cancer drugs cyclophosphamide, isophosphamide and triphosphamide suggests the existence of a correlation between the substance's chemotherapeutic efficacy and the (pi) - (sigma)(,NP) charge density at the trigonal nitrogen. Satisfactory correlations of the NQR spectra of 22 monosubstituted anilines with both the Hammett (sigma) parameters and the in vitro biological activities of the corresponding sulfanilamides have been found, indicating that the nitrogen lone-pair orbital is more sensitive than the nitrogen-carbon sigma orbital is to substituent effects. NQR spectra of several N-acetyl amino acids and related compounds are reported. The inductive effect of the chloroacetyl group on the nitrogen is discussed. A positive correlation between the (pi) - (sigma)(,NC) electron density at the nitrogen and the Taft inductive parameter (sigma)* is observed, suggesting that the nitrogen (pi) -charge density in the N-acetyl amino acids does not vary appreciably. Both ('14)N and ('35)Cl NQR data have been obtained for a series of compounds containing nitrogen directly bonded to chlorine. The existence of a linear correlation between the ('14)N and ('35)Cl quadrupole coupling constants is interpreted in terms of a simple model dealing with charge excesses and deficiencies at the respective nuclei. A study of two complexes of 4-aminopyridine (4AP) addresses the loss of pyridine nitrogen lone-pair charge upon formation of the strong and asymmetric N-H-N bond characteristic of these complexes. Evidence of hydrogen bonding interactions involving the amino nitrogens is found to be in agreement with a published neutron diffraction study

  19. 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

  20. 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. PMID:25649711

  1. Neutron-Induced Charged Particle Studies at LANSCE

    NASA Astrophysics Data System (ADS)

    Lee, Hye Young; Haight, Robert C.

    2014-09-01

    Direct measurements on neutron-induced charged particle reactions are of interest for nuclear astrophysics and applied nuclear energy. LANSCE (Los Alamos Neutron Science Center) produces neutrons in energy of thermal to several hundreds MeV. There has been an effort at LANSCE to upgrade neutron-induced charged particle detection technique, which follows on (n,z) measurements made previously here and will have improved capabilities including larger solid angles, higher efficiency, and better signal to background ratios. For studying cross sections of low-energy neutron induced alpha reactions, Frisch-gridded ionization chamber is designed with segmented anodes for improving signal-to-noise ratio near reaction thresholds. Since double-differential cross sections on (n,p) and (n,a) reactions up to tens of MeV provide important information on deducing nuclear level density, the ionization chamber will be coupled with silicon strip detectors (DSSD) in order to stop energetic charged particles. In this paper, we will present the status of this development including the progress on detector design, calibrations and Monte Carlo simulations. This work is funded by the US Department of Energy - Los Alamos National Security, LLC under Contract DE-AC52-06NA25396.

  2. Comparative study of analytical techniques for determining protein charge.

    PubMed

    Filoti, Dana I; Shire, Steven J; Yadav, Sandeep; Laue, Thomas M

    2015-07-01

    As interest in high-concentration protein formulations has increased, it has become apparent that routine, accurate protein charge measurements are necessary. There are several techniques for charge measurement, and a comparison of the methods is needed. The electrophoretic mobility, effective charge, and Debye-Hückel-Henry charge have been determined for bovine serum albumin, and human serum albumin. Three different electrophoretic methods were used to measure the electrophoretic mobility: capillary electrophoresis, electrophoretic light scattering, and membrane confined electrophoresis. In addition, the effective charge was measured directly using steady-state electrophoresis. Measurements made at different NaCl concentrations, pH, and temperatures allow comparison with previous charge estimates based on electrophoresis, Donnan equilibrium, and pH titration. Similar charge estimates are obtained by all of the methods. The strengths and limitations of each technique are discussed, as are some general considerations about protein charge and charge determination. PMID:25911989

  3. Clinicohematological Study of Thrombocytosis in Children

    PubMed Central

    Subramaniam, Nathiya; Mundkur, Suneel; Kini, Pushpa; Bhaskaranand, Nalini; Aroor, Shrikiran

    2014-01-01

    Introduction. Primary thrombocytosis is very rare in children; reactive thrombocytosis is frequently observed in children with infections, anemia, and many other causes. Aims and Objectives. To identify the etiology of thrombocytosis in children and to analyze platelet indices (MPV, PDW, and PCT) in children with thrombocytosis. Study Design. A prospective observational study. Material and Methods. A total of 1000 patients with thrombocytosis (platelet > 400 × 109/L) were studied over a period of 2 years. Platelet distribution width (PDW), mean platelet volume (MPV), and plateletcrit (PCT) were noted. Results. Of 1000 patients, 99.8% had secondary thrombocytosis and only two children had primary thrombocytosis (chronic myeloid leukemia and acute myelogenous leukemia, M7). The majority of the children belonged to the age group of 1month to 2 years (39.7%) and male to female ratio was 1.6 : 1. Infection with anemia (48.3%) was the most common cause of secondary thrombocytosis followed by iron deficiency alone (17.2%) and infection alone (16.2%). Respiratory infection (28.3%) was the predominant infectious cause observed. Thrombocytosis was commonly associated with IDA among all causes of anemia and severity of thrombocytosis increased with severity of anemia (P = 0.021). With increasing platelet count, there was a decrease in MPV (<0.001). Platelet count and mean PDW among children with infection and anemia were significantly higher than those among children with infection alone and anemia alone. None were observed to have thromboembolic manifestations. Conclusions. Primary thrombocytosis is extremely rare in children than secondary thrombocytosis. Infections in association with anemia are most commonly associated with reactive thrombocytosis and severity of thrombocytosis increases with severity of anemia. PMID:25006474

  4. 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-...

  5. C library for topological study of the electronic charge density.

    PubMed

    Vega, David; Aray, Yosslen; Rodríguez, Jesús

    2012-12-01

    The topological study of the electronic charge density is useful to obtain information about the kinds of bonds (ionic or covalent) and the atom charges on a molecule or crystal. For this study, it is necessary to calculate, at every space point, the electronic density and its electronic density derivatives values up to second order. In this work, a grid-based method for these calculations is described. The library, implemented for three dimensions, is based on a multidimensional Lagrange interpolation in a regular grid; by differentiating the resulting polynomial, the gradient vector, the Hessian matrix and the Laplacian formulas were obtained for every space point. More complex functions such as the Newton-Raphson method (to find the critical points, where the gradient is null) and the Cash-Karp Runge-Kutta method (used to make the gradient paths) were programmed. As in some crystals, the unit cell has angles different from 90°, the described library includes linear transformations to correct the gradient and Hessian when the grid is distorted (inclined). Functions were also developed to handle grid containing files (grd from DMol® program, CUBE from Gaussian® program and CHGCAR from VASP® program). Each one of these files contains the data for a molecular or crystal electronic property (such as charge density, spin density, electrostatic potential, and others) in a three-dimensional (3D) grid. The library can be adapted to make the topological study in any regular 3D grid by modifying the code of these functions. PMID:22865338

  6. National Children's Study: update in 2010.

    PubMed

    Hirschfeld, Steven; Songco, David; Kramer, Barnett S; Guttmacher, Alan E

    2011-01-01

    The National Children's Study will examine the effects of the environment and genetics on the growth, development, and health of children across the United States; it will follow participants from before birth until age 21 years. The goal of the study is to improve the health and well-being of children and contribute to understanding the roles various factors play in health and disease. Findings from the study will be made available as the research progresses, making potential benefits known to the public as soon as possible. A robust pilot study, or Vanguard Study, is underway to generate data for designing the subsequent Main Study. The goals of the Vanguard Study are feasibility, acceptability, and cost, and the goals of the Main Study will be exposure-response relationships and biological, environmental, and genetic interactions. The initial Vanguard Study experience among 7 study centers was successful in many ways, including delineating the topics to explore for the next phase of the Vanguard Study. Three different recruitment strategies are under evaluation to determine what approach to use for the Main Study. The organization of National Children's Study operations is currently based on a new decentralized business model. PMID:21259268

  7. THE TAMPA ASTHMATIC CHILDREN'S STUDY (TACS)

    EPA Science Inventory

    Conduct field monitoring studies with asthmatic children to identify and quantify factors that effect personal exposures in real-world environments and use the results of these studies to develop simple questions and/or measurements for classifying exposure in large studies as ...

  8. Sign Language Studies with Chimpanzees and Children.

    ERIC Educational Resources Information Center

    Van Cantfort, Thomas E.; Rimpau, James B.

    1982-01-01

    Reviews methodologies of sign language studies with chimpanzees and compares major findings of those studies with studies of human children. Considers relevance of input conditions for language acquisition, evidence used to demonstrate linguistic achievements, and application of rigorous testing procedures in developmental psycholinguistics.…

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

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

    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+ 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- beam from a 2.45 GHz microwave driven H- 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.

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

    PubMed

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

    2016-02-01

    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(+) 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(-) beam from a 2.45 GHz microwave driven H(-) 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. PMID:26932087

  11. 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.

  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. 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.

  14. 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

    ... sharing and other similar charges for children whose family income is at or below 150 percent of the FPL as long as— (a) Aggregate monthly enrollment fees, premiums, or similar charges imposed on a family... eligible family of the same size and income; (b) Any copayments, coinsurance, deductibles or...

  15. The National Children's Study: a 21-year prospective study of 100,000 American children.

    PubMed

    Landrigan, Philip J; Trasande, Leonardo; Thorpe, Lorna E; Gwynn, Charon; Lioy, Paul J; D'Alton, Mary E; Lipkind, Heather S; Swanson, James; Wadhwa, Pathik D; Clark, Edward B; Rauh, Virginia A; Perera, Frederica P; Susser, Ezra

    2006-11-01

    Prospective, multiyear epidemiologic studies have proven to be highly effective in discovering preventable risk factors for chronic disease. Investigations such as the Framingham Heart Study have produced blueprints for disease prevention and saved millions of lives and billions of dollars. To discover preventable environmental risk factors for disease in children, the US Congress directed the National Institute of Child Health and Human Development, through the Children's Health Act of 2000, to conduct the National Children's Study. The National Children's Study is hypothesis-driven and will seek information on environmental risks and individual susceptibility factors for asthma, birth defects, dyslexia, attention-deficit/hyperactivity disorder, autism, schizophrenia, and obesity, as well as for adverse birth outcomes. It will be conducted in a nationally representative, prospective cohort of 100,000 US-born children. Children will be followed from conception to 21 years of age. Environmental exposures (chemical, physical, biological, and psychosocial) will be assessed repeatedly during pregnancy and throughout childhood in children's homes, schools, and communities. Chemical assays will be performed by the Centers for Disease Control and Prevention, and banks of biological and environmental samples will be established for future analyses. Genetic material will be collected on each mother and child and banked to permit study of gene-environment interactions. Recruitment is scheduled to begin in 2007 at 7 Vanguard Sites and will extend to 105 sites across the United States. The National Children's Study will generate multiple satellite studies that explore methodologic issues, etiologic questions, and potential interventions. It will provide training for the next generation of researchers and practitioners in environmental pediatrics and will link to planned and ongoing prospective birth cohort studies in other nations. Data from the National Children's Study will

  16. 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…

  17. Study of central production of charged pionic modes at COMPASS

    SciTech Connect

    Bernhard, Johannes

    2010-08-05

    The COmmon Muon and Proton Apparatus for Structure and Spectroscopy is a fixed target experiment at the CERN SPS accelerator. In the years 2008 and 2009 the collaboration focused on hadron spectroscopy: data with hadronic beams at a momentum of 190 GeV/c impinging on hydrogen, lead, nickel and tungsten targets were taken. In the preparation for this run-time, the apparatus was adapted to measure the formation of resonances by both diffractive scattering and central production. In the latter case, the study of charged pionic channels is well-suited to search for members of the f{sub 0} particle family, including some of the glueball candidates. The analysis of the newly taken data has started, these proceedings are meant to give a status and overview of the current activities.

  18. Computer Simulation Study of Graphene Oxide Supercapacitors: Charge Screening Mechanism.

    PubMed

    Park, Sang-Won; DeYoung, Andrew D; Dhumal, Nilesh R; Shim, Youngseon; Kim, Hyung J; Jung, YounJoon

    2016-04-01

    Graphene oxide supercapacitors in the parallel plate configuration are studied via molecular dynamics (MD) simulations. The full range of electrode oxidation from 0 to 100% is examined by oxidizing the graphene surface with hydroxyl groups. Two different electrolytes, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMI(+)BF4(-)) as an ionic liquid and its 1.3 M solution in acetonitrile as an organic electrolyte, are considered. While the area-specific capacitance tends to decrease with increasing electrode oxidation for both electrolytes, its details show interesting differences between the organic electrolyte and ionic liquid, including the extent of decrease. For detailed insight into these differences, the screening mechanisms of electrode charges by electrolytes and their variations with electrode oxidation are analyzed with special attention paid to the aspects shared by and the contrasts between the organic electrolyte and ionic liquid. PMID:26966918

  19. Experimental study of low-energy charge transfer in nitrogen

    NASA Technical Reports Server (NTRS)

    Smith, A.

    1979-01-01

    Total charge transfer cross sections were obtained for the N2(+)-N2 system with relative translational ion energies between 9 and 441 eV. Data were obtained to examine the dependence of total cross section on ion energy. The effect of ion excitation on the cross sections was studied by varying the electron ionization energy in the mass spectrometer ion source over an electron energy range between 14.5 and 32.1 eV. The dependence of total cross section on the neutralization chamber gas pressure was examined by obtaining data at pressure values from 9.9 to 0.000199 torr. Cross section values obtained were compared with experimental and theoretical results of other investigations.

  20. Autistic-like behavior in CHARGE syndrome.

    PubMed

    Hartshorne, Timothy S; Grialou, Tina L; Parker, Kellie R

    2005-03-15

    Children with CHARGE syndrome frequently exhibit moderate to severe behavior difficulties, and are often diagnosed with obsessive-compulsive disorder, attention deficit disorder, Tourette syndrome, and autism. Hartshorne and Cypher (2004) surveyed parents of 100 children with CHARGE worldwide and confirmed the prevalence of behaviors that are associated with these disorders. They also found behaviors that could be described as typical of persons who are deafblind. The present study examined whether the autistic-like behaviors of children with CHARGE are more similar to those of children who are deafblind, to those of children who are autistic or are unique to CHARGE. Surveys including the Autism Behavior Checklist (ABC) were mailed to families of 204 children with CHARGE, and 160 usable surveys were returned (78%). Total scores on the ABC for children with CHARGE were significantly different from the norms for those with autism, and those who were deafblind. However, the variance for CHARGE was larger than for the normative groups, and 27.5% of those with CHARGE could be classified as autistic. The pattern of subscale scores for those with CHARGE differed from the other normative groups. PMID:15637726

  1. 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,…

  2. High lying N* studies in electromagnetic double charged pion production

    SciTech Connect

    V. I. Mokeev; M. Ripani; M. Anghinolfi; M. Battaglieri; R. De Vita; G. V. Fedotov; E. N. Golovach; B. S. Ishkhanov; M. V. Osipenko; G. Ricco; V. Sapunenko; M. Taiuti

    2002-06-07

    A phenomenological model for double charged pion production is presented, aimed to exact N* electromagnetic form factors from measured observables (differential cross-sections, asymmetries). The preliminary results of CLAS data analysis on double charged pion production by virtual photons are discussed, focusing on high lying N* electromagnetic excitation and signals from possible ''missing'' baryon states.

  3. 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…

  4. 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…

  5. 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. PMID:24682808

  6. 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

  7. ANALYSIS OF NHEXAS DATA FROM THE CHILDREN,S PESTICIDE EXPOSURE STUDY IN MINNESOTA

    EPA Science Inventory

    The "Minnesota Children's Pesticide Exposure Study" (MNCPES) evaluated the feasibility of conducting a multipathway exposure monitoring study with a sample of children, and implemented a strategy for collection and integration of survey information (e.g., pesticide usage and acti...

  8. Studying and applying channeling at extremely high bunch charges

    SciTech Connect

    Carrigan, R.A.; /Fermilab

    2005-01-01

    The potentially high plasma densities possible in solids might produce extremely high acceleration gradients. However solid-state plasmas could pose daunting challenges. Crystal channeling has been suggested as a mechanism to ameliorate these problems. A high-density plasma in a crystal lattice could quench the channeling process. There is no experimental or theoretical guidance on channeling for intense charged particle beams. An experiment has been carried out at the Fermilab A0 photoinjector to observe electron channeling radiation at high bunch charges. An electron beam with up to 8 nC per electron bunch was used to investigate the electron-crystal interaction. No evidence was found of quenching of channeling at charge densities two orders of magnitude larger than in earlier experiments. Possible new channeling experiments are discussed for the much higher bunch charge densities and shorter times required to probe channeling breakdown and plasma behavior.

  9. 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.

  10. Observational study of children with aerophagia.

    PubMed

    Loening-Baucke, Vera; Swidsinski, Alexander

    2008-09-01

    Aerophagia is a rare disorder in children. The diagnosis is often delayed, especially when it occurs concomitantly with constipation. The aim of this report is to increase awareness about aerophagia. This study describes 2 girls and 7 boys, 2 to 10.4 years of age, with functional constipation and gaseous abdominal distention. The abdomen was visibly distended, nontender, and tympanitic in all. Documenting less distention on awakening helped to make the diagnosis. Air swallowing, belching, and flatulence were infrequently reported. The rectal examination often revealed a dilated rectal ampulla filled with gas or stool and gas. The abdominal X-ray showed gaseous distention of the colon in all and of the stomach and small bowel in 8 children. Treatment consisted of educating parents and children about air sucking and swallowing, encouraging the children to stop the excessive air swallowing, and suggesting to them not to use drinking straws and not to drink carbonated beverages. The aerophagia resolved in all in 2 to 20 months (mean=8 months). PMID:18445758

  11. 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

    2009-06-01

    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. PMID:19425035

  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. 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

  14. 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…

  15. A temperature dependent study on charge dynamics in organic molecular device: Effect of shallow traps on space charge limited behavior

    NASA Astrophysics Data System (ADS)

    Mukherjee, A. K.; Kavala, A. K.

    2014-04-01

    Shallow traps play a significant role in influencing charge dynamics through organic molecular thin films, such as pentacene. Sandwich cells of pentacene capped by gold electrodes are an excellent specimen to study the nature of underlying charge dynamics. In this paper, self-consistent numerical simulation of I-V characteristics is performed at various temperatures. The results have revealed negative value of Poole Frenkel coefficient. The location of trap energy level is found to be located at 0.24 eV above the highest occupied molecular orbit (HOMO) level of pentacene. Other physical parameters related to trap levels, such as density of states due to traps and effective carrier density due to traps, have also been estimated in this study.

  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. 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…

  18. Miniaturized high-resolution mass/charge spectrograph /design study/

    NASA Technical Reports Server (NTRS)

    Taylor, L. H.

    1969-01-01

    Use of a double-focusing mass/charge spectrograph weighing less than 25 pounds is feasible for solar wind experiments. Instrument has a parallel-plate energy filter between the ion source and the double focusing units which alleviates the problem of designing an ion source of small energy spread.

  19. 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. PMID:21483419

  20. 75 FR 51467 - ASK (Assess Specific Kinds of CHILDREN Challenges for Neurologic Devices) Study Children Workshop...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-20

    ... HUMAN SERVICES Food and Drug Administration ASK (Assess Specific Kinds of CHILDREN Challenges for Neurologic Devices) Study Children Workshop; Public Workshop; Request for Comments AGENCY: Food and Drug... Administration (FDA) is announcing a public workshop entitled ASK (Assess Specific Kinds of CHILDREN...

  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. Study Questions Use of Antidepressants for Children, Teens

    MedlinePlus

    ... html Study Questions Use of Antidepressants for Children, Teens They were seen as mostly ineffective and sometimes ... June 8, 2016 (HealthDay News) -- Treating children and teens suffering from depression with antidepressants may be both ...

  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. 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 ...

  5. Teaching Social Studies in the Primary Grades with Children's Literature.

    ERIC Educational Resources Information Center

    Stoddard, Ann H.

    Intended for primary school teachers involved in social studies instruction, this paper offers guidelines for selecting and using children's literature to teach social studies concepts. The paper first deals with selecting children's literature works, presenting basic considerations relating children's developmental stages to characteristics of…

  6. Identifying the Missing Links in the Study of Latchkey Children.

    ERIC Educational Resources Information Center

    Galambos, Nancy L.; Garbarino, James

    Despite widespread and growing public and professional concern for latchkey children (children unsupervised before or after school), only a few empirical studies of such children are available. This study examined school adjustment, intrinsic versus extrinsic orientation in the classroom, academic achievement, and fear levels in fifth- and…

  7. A study of malnourished children in children's hospital Lusaka (Zambia).

    PubMed

    Khan, A A; Gupta, B M

    1979-01-01

    The parents of 200 malnourished childred referred and admitted over the July-December 1976 period to the nutrition wing of the Children's University Teaching Hospital, Zambia, were interviewed in an effort to understand the home environment of malnourished children in Lusaka, Zambia. The 1974 incidence of malnutrition in Zambia was about 23% with higher prevalences of marasmus and moderate malnutrition. There were 9.4% severly malnourished children admitted in 1976 as compared with less than 1% in 1971. Many of these children were admitted very late in a hypothermic shocked state which is directly responsible for the increasing incidence of mortality over these years. Plasma or blood transfusion is a standard procedure in all shocked cases of kwashiorkor, yet many of the children still die within 24 hours of admission. Malnutrition incidence was found to be closely linked to the rise in price index. The majority of the children were admitted from the rainy months November to March, the time associated with a higher incidence of gastroenteritis, respiratory infections, and measles. 88% of the children were between 1-3 years old. Marasmus (33.5%) and marasmic kwashiorkor (40.5%) were more frequent. 63% of the malnourished childred had attended the child health clinics in their infancy and were immunized but discontinued attendance one vaccination was completed. The problem of malnutrition was in the toddler age group. 86% of the childred came from urban slums and periurban areas; 83% were from unitary families, living in 1 or 2 bedroom houses with no separate provision for a kitchen. Rural families (14%) were living as joint families. 32% of the children were from large families. 52% of the parents were employed as casual laborers and earning under US $35 per month. There were only 10 families with earnings in excess of US $125 per month and only 8 had good sources of income from farms. As many as 68.5% children were experiencing 1 or more adverse factors which

  8. 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…

  9. 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.

  10. 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.

  11. 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

    2014-05-01

    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. PMID:24811649

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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.

  13. 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.

  14. Microbeam Studies of Diffusion Time Resolved Ion Beam Induced Charge Collection from Stripe-Like Junctions

    SciTech Connect

    GUO,B.N.; BOUANANI,M.E.; RENFROW,S.N.; WALSH,DAVID S.; DOYLE,BARNEY L.; ATON,T.J.; SMITH,E.B.; BAUMANN,R.C.; DUGGAN,J.L.; MCDANIEL,F.D.

    2000-06-14

    To design more radiation tolerant Integrated Circuits (ICs), it is essential to create and test accurate models of ionizing radiation induced charge collection dynamics within microcircuits. A new technique, Diffusion Time Resolved Ion Beam Induced Charge Collection (DTRIBICC), is proposed to measure the average arrival time of the diffused charge at the junction. Specially designed stripe-like junctions were experimentally studied using a 12 MeV carbon microbeam with a spot size of 1 {micro}m. The relative arrival time of ion-generated charge is measured along with the charge collection using a multiple parameter data acquisition system. The results show the importance of the diffused charge collection by junctions, which is especially significant in accounting for Multiple Bit Upset (MBUs) in digital devices.

  15. 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.…

  16. Children's perceptions of injuries: a qualitative study in Sweden.

    PubMed

    Dale, Richard Allan; Hasselberg, Marie; Jakobsson, Annika; Hensing, Gunnel

    2013-01-01

    To understand one of the major public health problems for children, it is important to consider the children's perspective. The purpose of this qualitative study was to explore, describe, and categorize children's perceptions of injury severity and children's explanations of the injuries they experience. A total of 29 students from six randomly selected schools were interviewed in age groups of 9, 13, and 17 years. Manifest content analysis according to Graneheim and Lundman (2004) was used to categorize children's own statements. Need of medical attention, long-term consequences, and familiarity with the injury risk situation were identified as important determinants of children's perception of injury severity. Three categories emerged from children's explanations of their injuries: "Because of Me" (beliefs, lack of concentration, health conditions, and lack of awareness of risk), "Because of the Situation" (rain, ice, wind, animals, inanimate objects, constructions, and the children's games), and "Just Inexplicable" to the children. Findings suggest that children have a wide perception of injury severity and that children's beliefs of injury causation, as well as children's familiarity with injury risk situations, need to be considered in future studies focusing on the development of childhood injury prevention strategies. Additionally, results suggest that sometimes children cannot or do not want to explain their injuries. PMID:24308087

  17. 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…

  18. Study on plasma parameters and dust charging in an electrostatically plugged multicusp plasma device

    SciTech Connect

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

    2011-06-15

    The effect of the electrostatic confinement potential on the charging of dust grains and its relationship with the plasma parameters has been studied in an electrostatically plugged multicusp dusty plasma device. Electrostatic plugging is implemented by biasing the electrically isolated magnetic multicusp channel walls. The experimental results show that voltage applied to the channel walls can be a controlling parameter for dust charging.

  19. 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…

  20. 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…

  1. 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

  2. The National Children's Study: An Introduction and Historical Overview.

    PubMed

    Hudak, Mark L; Park, Christina H; Annett, Robert D; Hale, Daniel E; McGovern, Patricia M; McLaughlin, Thomas J; Dole, Nancy; Kaar, Jill L; Balsam, Marion J

    2016-06-01

    The National Children's Study (NCS) was an ambitious attempt to map children's health and development in a large representative group of children in the United States. In this introduction, we briefly review the background of the NCS and the history of the multiple strategies that were tested to recruit women and children. Subsequent articles then detail the protocols and outcomes of 4 of the recruitment strategies. It is hoped that lessons learned from these attempts to define a study protocol that could achieve the initial aims of the NCS will inform future efforts to conceptualize and execute strategies to provide generalizable insights on the longitudinal health of our nation's children. PMID:27251867

  3. 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.

  4. Superwarfarin poisoning in children: a prospective study.

    PubMed

    Smolinske, S C; Scherger, D L; Kearns, P S; Wruk, K M; Kulig, K W; Rumack, B H

    1989-09-01

    This prospective study was undertaken to determine the incidence, severity, time of onset, and duration of coagulopathy in children following accidental ingestion of long-acting anticoagulant rodenticides, often called "superwarfarins." Of 110 children, who ingested superwarfarins and in whom one or more prothrombin time values were obtained, 8 had a prothrombin time ratio (patient to control) of greater than or equal to 1.2, indicative of anticoagulation. Prothrombin time values obtained 48 hours after ingestion were more likely to be prolonged (6/34, 17.6%) than values obtained 24 hours after ingestion (2/104, 1.9%) (P less than .005). The occurrence of an abnormal prothrombin time could not be predicted based on the history of amount ingested or on the presence of the characteristic green-blue product dye in or around the child's mouth. Acute toxicity was evidenced by transient abdominal pain, vomiting, and heme positive stools in 2 patients. The duration of prothrombin time prolongation could not be determined because of the few values obtained after 48 hours. To detect all possible abnormal prothrombin time values, 24- and 48-hour determinations are recommended after a child has ingested a superwarfarin. PMID:2771552

  5. 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.

  6. 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.

  7. Study of anomalous charge collection efficiency in heavily irradiated silicon strip detectors

    NASA Astrophysics Data System (ADS)

    Mikuž, M.; Cindro, V.; Kramberger, G.; Mandić, I.; Zavrtanik, M.

    2011-04-01

    Anomalous charge collection efficiency observed in heavily irradiated silicon strip detectors operated at high bias voltages has been studied in terms of a simple model and experimentally using 25 ns shaping electronics and transient current technique (TCT) with edge-on laser injection. The model confirmed qualitatively the explanation by electron impact ionization in the high electric field close to the strips, but failed in the quantitative description of the collected charge. First results on a Hamamatsu strip detector irradiated to 5×1015 neq/cm2 and operated at bias voltages in excess of 1000 V exhibit charge collection similar to what obtained on Micron devices. TCT tests with local charge injection by a laser confirm the validity of a linear extrapolation of trapping to very high fluences and reveal significant charge collection from the non-depleted volume of the detector.

  8. 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.

  9. 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…

  10. Theoretical study of the amphoteric oxide nanoparticle surface charge during multi-particle interactions in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Alfimov, A. V.; Aryslanova, E. M.; Chivilikhin, S. A.

    2015-11-01

    Nanoparticle surface charge plays an important role in many biological applications. In this study, an analytical surface charging model for the amphoteric oxide nanoparticles has been presented. The model accounts for the particle's electric double layer self-action on the charging process and the charge regulation during multi-particle interactions in aqueous solutions. The employment of the model allows to explicitly describe the nanoparticle agglomeration process and the accompanying agglomerate surface charge variation.

  11. 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.

  12. DEVELOPING A QUALITY SYSTEM FOR THE NATIONAL CHILDREN'S STUDY

    EPA Science Inventory

    A Quality Management Plan (QMP) is under development for a national, interagency, long-term study known as the National Children's Study (NCS). The NCS is a study to examine the effects of environmental influences on the health and development of more than 100,000 children acros...

  13. 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.

  14. 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.

  15. 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.

  16. 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…

  17. 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...

  18. Young Children Category Learning: A Training Study

    ERIC Educational Resources Information Center

    Taverna, Andrea Sabina; Peralta, Olga Alicia

    2013-01-01

    From an integrative approach, this work focuses on the role of conceptual mechanisms, such as comparison and conceptual-based inference, and sociopragmatic support in young children's taxonomic categorization. "Experiment 1" assessed whether 3-, 4-, and 6-year-old children succeed in detecting taxonomic relations on their own. A…

  19. 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.

  20. Children's Questions: A Study of Questions Children Ask While Learning to Use a Computer.

    ERIC Educational Resources Information Center

    Shaw, Donna Gail; And Others

    1985-01-01

    Describes a study conducted at a Texas elementary school which examined the types of questions second-grade children ask as they are taught to use microcomputers. A classification of questions into eight categories indicates children asked most about keyboard, data entry, and meaning of program instructions. (MBR)

  1. Dynamical Studies of Charged Di-Block Copolymer in Different Dielectric Media

    SciTech Connect

    Goswami, Monojoy; Kumar, Rajeev; Sumpter, Bobby G; Mays, Jimmy

    2011-01-01

    Brownian Dynamics simulations are carried out to understand the effect of temperature and dielectric constant of the medium on microphase separation of charged-neutral diblock copolymer systems. For different dielectric media, we focus on the effect of temperature on the morphology and dynamics of model charged diblock copolymers. In this study we examine in detail a system with a partially charged block copolymer consisting of 75% neutral blocks and 25% of charged blocks with 50% degree of ionization. Our investigations show that due to the presence of strong electrostatic interactions between the charged block and counterions, the block copolymermorphologies are rather different than those of their neutral counterpart at low dielectric constant, however at high dielectric constant the neutral diblock behaviors are observed. This article highlights the effect of dielectric constant of two different media on different thermodynamic and dynamic quantities. At low dielectric constant, the morphologies are a direct outcome of the ion-counterion multiplet formation. At high dielectric constant, these charged diblocks behavior resembles that of neutral and weakly charged polymers with sustainable long-range order. Similar behavior has been observed in chain swelling, albeit with small changes in swelling ratio for large changes in polarity of the medium. The results of our simulations agree with recent experimental results and are consistent with recent theoretical predictions of counterion adsorption on flexible polyelectrolytes.

  2. Light-induced EPR study of charge transfer in poly(3-hexylthiophene)/fullerene bulk heterojunction

    SciTech Connect

    Krinichnyi, V. I.; Yudanova, E. I.; Denisov, N. N.

    2009-07-28

    The first results of the light-induced EPR study of magnetic, relaxation, and dynamic parameters of charge carriers background photoinduced by optical photons (1.7-3.4 eV) in poly(3-hexylthiophene)/fullerene bulk heterojunctions are described. All magnetic resonance parameters for positively charged polaron and negatively charged fullerene ion-radical in radical pairs photoinduced in the composite were determined separately by the steady-state microwave saturation method. Paramagnetic susceptibility of charge carriers reflects their activation dynamics and exchange interaction. A decay of long-living radical pairs depends on the spatial distance between photoinduced charge carriers. The one-dimensional polaron diffusion along the polymer chain and fullerene rotation near the main molecular axis was shown to follow activation Elliot hopping model and to be governed by photon energy. The difference in activation energies of the charge carriers' dynamics and in their dependence on the exciting photon energy proves their noninteracting character in the polymer/fullerene composite. Main magnetic, relaxation and dynamics parameters of charge carriers are governed by the photon energy band due to inhomogeneity of distribution of polymer and fullerene domains in the composite.

  3. 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…

  4. STUDIES IN CHILDREN EXPOSED TO LOW LEVELS OF LEAD

    EPA Science Inventory

    Two separate studies were conducted with the overall objective of examining the impact of lead at low dose on the neuropsychological function of children. In the first study, a sample of children identified as having elevated lead levels in the dentine of shed deciduous teeth (N ...

  5. EATING PATTERNS AND OBESITY IN CHILDREN: THE BOGALUSA HEART STUDY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Childhood obesity is a growing public health problem. This study examined the association between eating patterns and overweight status in children who participated in the Bogalusa Heart Study. A single 24-hour dietary recall was collected on a cross-sectional sample of 1562 children aged 10 years (...

  6. Metalinguistic Awareness: A Study of Verbal Play in Young Children.

    ERIC Educational Resources Information Center

    Schwartz, Judy I.

    This paper presents a study of metalinguistic awareness in young children. Metalinguistic awareness refers to the child's ability to concentrate on the sounds and patterns of language rather than on its communicative aspects. Metalinguistic awareness was studied by analyzing the verbal play and verbal games of 149 children from 6 months to 10…

  7. 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 ...

  8. A study of charging in the presence of a gaseous environment

    NASA Astrophysics Data System (ADS)

    Tang, Xiaohu

    Charge accumulation in insulating or semiconducting samples due to electron beam irradiation is one of the key problems in electron microscopy. One of the most promising techniques for reducing the severity of such charging is to surround the sample with a low-pressure atmosphere of a gas. The charging behavior of a number of materials, surrounded by a variety of gases, has been determined to identify the important factors which control charging under these conditions. The magnitude of the surface potential was deduced from an analysis of X-ray spectra from the surface. The relationship between surface charge, gas pressure, and gas type are measured, and the charging reduction efficiency (CRE) is compared. In addition, the use of localized gas jets to alleviate charging without causing beam broadening has been investigated. The gas distribution emanating from the pipe is simulated by a molecular dynamics Monte Carlo model. The effect of the pipe shape on gas distribution is studied. A method to obtain a desired gas distribution by optimizing the gas jet arrangement is proposed. As a part of this thesis, a simple technique which provides a rapid way of visualizing charging phenomena is described and its spatial characteristics is examined. The migration of small particles to form a Lichtenberg image is driven by the surface potentials, which are a direct function of the distribution of high-energy electrons at the surface. The Lichtenberg patterns qualitatively and quantitatively demonstrate the distribution of the surface electric field resulting from the surface charging. The combination of the PPM, nanoparticles, and the Lichtenberg technique might permit high-resolution direct metal imprinting.

  9. Who's in Charge Here? Ownership Issues with Literature Study Guides.

    ERIC Educational Resources Information Center

    Radencich, Marguerite Cogorno

    1998-01-01

    Presents a rationale and procedure for evaluating literature study guides based on J. Langer's model for literature study and B. Cambourne's conditions for learning. Compares three guides using the evaluation procedure. Shows great differences in treatments of the same books in five publishers' guides. (CR)

  10. 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....

  11. 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…

  12. 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…

  13. 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…

  14. 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…

  15. 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…

  16. 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…

  17. Expressed Reading Interests of Young Children: An International Study.

    ERIC Educational Resources Information Center

    Robinson, H. Alan; And Others

    A study of the current expressed reading interests of children in the first two years of school conducted in ten countries--Austria, Canada, England, Israel, Italy, Japan, the Netherlands, Panama, Sweden, and the United States--is reported in this paper. Over 2,000 children drew pictures about what they would best like to read or have read to…

  18. 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…

  19. 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 requested. The…

  20. [Achievement Test Correlation Study: Survey of 40 Children.

    ERIC Educational Resources Information Center

    Smith, William F.

    A comprehensive profile of 40 Title I children from a Chattanooga school was obtained by parent and child interviews. The profile was part of a clinical evaluation in the "East Fifth Street Middle School Special Study." Although some findings were unique for each child, some occurred in the history of several children. Generally, the Title I…

  1. Ascariasis and malnutrition. A study in urban Ethiopian children.

    PubMed

    Freij, L; Meeuwisse, G W; Berg, N O; Wall, S; Gebre-Medhin, M

    1979-07-01

    Treatment of 13 urban Ethiopian children with mild ascariasis did not produce any evidence of improved intestinal morphology and absorption or nutritional status. Ascariasis treatment had no impact on anthropometric measures in an additional study group of 84 children. A review of the literature reveals that the nutritional consequences of ascariasis are uncertain. PMID:453069

  2. Group Therapy for Adult Children of Alcoholics: Case Studies.

    ERIC Educational Resources Information Center

    Corazzini, John G.; And Others

    1987-01-01

    Discusses survival roles adopted by children growing up in families where alcohol is abused, relating them to birth order, and emphasizing their maladaptivity for later adult interactions. Presents case studies of two common roles of adult children of alcoholics (ACAs), those of hero and scapegoat, and demonstrates how ACAs interact in a mixed,…

  3. A Follow-Up Study of Abused Children

    ERIC Educational Resources Information Center

    Kent, James T.

    1976-01-01

    Investigated in a followup study of 219 NAT (non-accidental trauma) children and 159 NEG (gross neglect) children were the specific effects of abusive environments on psychosocial development and the possible reversibility of these effects with intervention through foster home placement. Available from: EC 090 265. (Author/IM)

  4. Barriers to Adoption of Special Needs Children: A National Study.

    ERIC Educational Resources Information Center

    McCullagh, James G.

    This exploratory study analyzed the incidence and nature of barriers experienced by applicants wishing to adopt special needs children, defined as: "children who are older, have physical disabilities, are emotionally troubled, or are mentally retarded. Many are Black or Hispanic. Some are brothers and sisters who need a home together." Between…

  5. A STUDY OF DIAGNOSTIC SERVICES FOR BRAIN-INJURED CHILDREN.

    ERIC Educational Resources Information Center

    HENNESSY, ERNA

    THE PURPOSES OF THIS STUDY WERE (1) TO INVESTIGATE THE EARLY RECOGNITION OF BRAIN INJURY SYMPTOMS BY PARENTS, (2) TO EXPLORE THE DIAGNOSTIC PROBLEMS AND HISTORIES OF BRAIN INJURED CHILDREN AND THEIR PARENTS, AND (3) TO REVIEW THE EXISTING AND NEEDED FACILITIES FOR BRAIN INJURED CHILDREN IN NEW JERSEY. IN 1964, A QUESTIONNAIRE ELICITING…

  6. 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.…

  7. 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…

  8. 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.

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

    MedlinePlus Videos and Cool Tools

    ... develop treatments, drugs, and devices specific to children. Resources for a Wide Range of Audiences The Children ... the general public. Last Updated: August 3, 2015 Resources Educational Website - English / Spanish Paper Kingdom Video Game ...

  10. X-ray charge density study of chemical bonding in skutterudite CoSb{sub 3}

    SciTech Connect

    Ohno, Atsuko; Sasaki, Satoshi; Nishibori, Eiji; Aoyagi, Shinobu; Sakata, Makoto; Iversen, Bo Brummerstedt

    2007-08-01

    The experimental charge density of nondoped CoSb{sub 3} has been determined by the maximum entropy method (MEM) using low temperature (10 K), short wavelength (0.42 A), and high-resolution (d{sub min}=0.33 A) synchrotron x-ray powder diffraction data measured at SPring-8, Japan. The MEM charge density clearly reveals three types of charge density overlap between atoms in CoSb{sub 3}. The four Sb atoms form an Sb{sub 4} ring, and the MEM charge densities at two types of Sb-Sb midpoints are 0.35 and 0.50 e A{sup -3}. The charge density overlap between the Co and Sb atoms at the midpoint is 0.52 e A{sup -3}, which is larger than the values observed at the Sb-Sb midpoints. The nature of the chemical bonding observed in the present MEM charge density is consistent with a previous theoretical study by Lefebvre-Devos et al. [Phys. Rev. B 63, 125110 (2001)].

  11. Photophysical studies of metal to ligand charge transfer involving quadruply bonded complexes of molybdenum and tungsten.

    PubMed

    Chisholm, Malcolm H; Brown-Xu, Samantha E; Spilker, Thomas F

    2015-03-17

    Photoinduced metal-to-ligand charge transfer transitions afford numerous applications in terms of photon energy harvesting. The majority of metal complexes studied to date involve diamagnetic systems of d(6), d(8), and d(10) transition metals. These typically have very short-lived, ∼100 fs, singlet metal to ligand charge transfer ((1)MLCT) states that undergo intersystem crossing to triplet metal to ligand charge transfer ((3)MLCT) states that are longer lived and are responsible for much of the photophysical studies. In contrast, the metal-metal quadruply bonded complexes of molybdenum and tungsten supported by carboxylate, O2CR, and related amidinate ligands (RN)2C(R') have relatively long-lived (1)MLCT states arising from M2δ to Lπ* transitions. These have lifetimes in the range 1-20 ps prior to intersystem crossing to T1 states that may be (3)MLCT or (3)MMδδ* with lifetimes of 1-100 ns and 1-100 μs, respectively. The M2 quadruply bonded complexes take the form M2L4 or M2L4-nL'n where n = 1-3. Thus, in their photoexcited MLCT states, these compounds pose the question of how the charge resides on the ligands. This Account reviews the current knowledge of how charge is positioned with time in S1 and T1 states with the aid of active IR reported groups located on the ligands, for example, C≡X multiple bonds (X = C, N, or O). Several examples of localized and delocalized charge distributions are noted along with kinetic barriers to the interconversion of MLCT and δδ* states. On the 50th anniversary of the recognition of the MM quadruple bond, these complexes are revealing some remarkable features in the study of the photophysical properties of metal-ligand charge transfer states. PMID:25695495

  12. Executive function in CHARGE syndrome.

    PubMed

    Hartshorne, Timothy S; Nicholas, Jude; Grialou, Tina L; Russ, Joanna M

    2007-07-01

    This study addressed the presence of executive dysfunction in children with CHARGE syndrome, a genetic disorder with multiple physical anomalies and severe challenging behaviors. Ninety-eight children were included in the study. More than half received clinically significant scores on the Behavior Rating Inventory of Executive Function (BRIEF; Gioia et al., 2000) scales of Shift, Monitor, and the Behavioral Regulation Index, with additional high scores on Inhibit and the Global Executive Composite. Associations were found with the age the child first walked, scores on the Autism Behavior Checklist (ABC; Krug et al., 1993), and being classified as deafblind. Difficulties with making transitions and flexible problem solving, monitoring their work and their effect on others, and acting on impulse, may be related to the behavioral difficulties exhibited by children with CHARGE. Interventions targeting improved self-regulation may help to manage this challenging behavior. PMID:17564850

  13. 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,...

  14. 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.

  15. Multiple powder diffraction data for an accurate charge density study using synchrotron radiation x-ray

    NASA Astrophysics Data System (ADS)

    Kasai, Hidetaka; Nishibori, Eiji

    2016-04-01

    In recent years multiple synchrotron radiation (SR) powder x-ray diffraction profiles have been successfully applied to advanced structural studies such as an accurate charge density study and a structure determination from powder diffraction. The results have been presented with several examples. Abilities and future prospects have been discussed using state of the art powder diffraction data.

  16. The Zambia Children's KS-HHV8 Study: Rationale, Study Design, and Study Methods

    PubMed Central

    Minhas, Veenu; Crabtree, Kay L.; Chao, Ann; Wojcicki, Janet M.; Sifuniso, Adrian M.; Nkonde, Catherine; Kankasa, Chipepo; Mitchell, Charles D.; Wood, Charles

    2011-01-01

    The epidemic of human immunodeficiency virus in Zambia has led to a dramatic rise in the incidence of human herpesvirus-8 (HHV-8)–associated Kaposi's sarcoma in both adults and children. However, there is a paucity of knowledge about the routes of HHV-8 transmission to young children. The Zambia Children's KS-HHV8 Study, a large, prospective cohort study in Lusaka, Zambia, was launched in 2004 to investigate the role of household members as a source of HHV-8 infection in young children and social behaviors that may modify the risk of HHV-8 acquisition. This cohort is distinct from other epidemiologic studies designed to investigate HHV-8 incidence and transmission because it recruited and followed complete households in the urban central African context. Between July 2004 and March 2007, 1,600 households were screened; 368 households comprising 464 children and 1,335 caregivers and household members were enrolled. Follow-up of this population continued for 48 months postrecruitment, affording a unique opportunity to study horizontal transmission of HHV-8 and understand the routes and sources of transmission to young children in Zambia. The authors describe the study rationale, design, execution, and characteristics of this cohort, which provides critical data on the epidemiology and transmission of HHV-8 to young children in Zambia. PMID:21447476

  17. High pressure study of charge transfer complexes and radical ion salts: A review

    NASA Astrophysics Data System (ADS)

    Singh, Yadunath

    2016-05-01

    High pressure is an important tool to study of material in respect of variation in interatomic distances, phase transitions and other physical properties. The pressure study of charge transfer complexes and radical ion salts provide us a better understanding about the effect of charge transfer forces, structural changes, formation of new ground states, suppression ofPeierls distortions occurs particularly at low temperatures and the intra-molecular overlapping etc. in these materials. The pressure plays a significant role in bringing superconducting transitions in the organic materials.

  18. Charge transport properties of CN-substituted furan based organic semiconductor: A density functional study

    NASA Astrophysics Data System (ADS)

    Sahoo, Smruti Ranjan; Sahu, Sridhar; Sharma, Sagar

    2016-05-01

    We report a density functional study for charge transport properties of substituted furan molecule. Reorganization energy(λ), charge transfer integral(t) and mobility(μ) have been studied along with their structural properties within the framework of dimmer model. We found the electron withdrawing -CN groups decrease the reorganization energy and band gap of the conjugated molecules, resulting in more electron injection across the barrier and hence assigning n-type characteristics to the system. Furthermore, substitution of -CN group is also found to enhance the electron mobility of oligomer as compared to monomer unit and the bare furan molecule.

  19. Teaching Entrepreneurship to Children: A Case Study

    ERIC Educational Resources Information Center

    do Paco, Arminda; Palinhas, Maria Joao

    2011-01-01

    Nowadays few young people are prepared to consider setting up and managing their own business as a realistic and attractive career option. It is therefore necessary to expose children to the concept of entrepreneurship from a very early age, which means that the school has a fundamental role to play in this task. This research seeks to understand…

  20. 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)

  1. Branching Out: Forest Studies with Children.

    ERIC Educational Resources Information Center

    Argast, Susan; Macdonald, Cheryl

    1996-01-01

    Describes activities which sharpen awareness of trees through the senses in this first of a two-part integrated unit for teaching children about forest ecosystems. Students interact and work in collaborative groups; learn about the impact of forests on daily life; explore the interdependence of plants, animals, soil, water, air, and light; explore…

  2. A review of studies on ion thruster beam and charge-exchange plasmas

    NASA Technical Reports Server (NTRS)

    Carruth, M. R., Jr.

    1982-01-01

    Various experimental and analytical studies of the primary beam and charge-exchange plasmas of ion thrusters are reviewed. The history of plasma beam research is recounted, emphasizing experiments on beam neutralization, expansion of the beam, and determination of beam parameters such as electron temperature, plasma density, and plasma potential. The development of modern electron bombardment ion thrusters is treated, detailing experimental results. Studies on charge-exchange plasma are discussed, showing results such as the relationship between neutralizer emission current and plasma beam potential, ion energies as a function of neutralizer bias, charge-exchange ion current collected by an axially moving Faraday cup-RPA for 8-cm and 30-cm ion thrusters, beam density and potential data from a 15-cm ion thruster, and charge-exchange ion flow around a 30-cm thruster. A 20-cm thruster electrical configuration is depicted and facility effects are discussed. Finally, plasma modeling is covered in detail for plasma beam and charge-exchange plasma.

  3. Studies of Space Charge Effects in the Proposed CERN PS2

    SciTech Connect

    Qiang, Ji; Ryne, Robert; De Maria, Riccardo; Macridin, Alexandru; Spentzouris, Panagiotis; Papaphilippou, Yannis; Wienands, Ulrich; /SLAC

    2012-06-22

    A new proton synchrotron, the PS2, is under design study to replace the current proton synchrotron at CERN for the LHC upgrade. Nonlinear space charge effects could cause significant beam emittance growth and particle losses and limit the performance of the PS2. In this paper, we report on studies of the potential space-charge effects at the PS2 using three-dimensional self-consistent macroparticle tracking codes, IMPACT, MaryLie/IMPACT, and Synergia. We will present initial benchmark results among these codes. Effects of space-charge on the emittance growth, especially due to synchrotron coupling, aperture sizes, initial painted distribution, and RF ramping scheme will also be discussed.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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)

  9. 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…

  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. 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.

  12. Kaduna Beggar Children: A Study of Child Abuse and Neglect in Northern Nigeria.

    ERIC Educational Resources Information Center

    Ojanuga, Durrenda Nash

    1990-01-01

    Pilot study reports on use of children as street beggars in Kaduna, Nigeria. Begging usually occurs because children's parents are poor, disabled. Children may also be handicapped. Other child beggars are poor boys studying with Koranic mallams; children must provide own food and money for lessons by begging. Measures to assist beggar children are…

  13. Photophysical properties of charge transfer pairs encapsulated inside macrocycle cage: A density functional theory study

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, Arkamita; Pati, Swapan K.

    2015-03-01

    Density functional theory calculations have been performed on three charge transfer donor-acceptor (D-A) molecular pairs, i.e. naphthalene-diamine (Naph) and tetrathiafulvalene (TTF) molecules as electron donors and benzene-diimide (Diimide) and tetracyanoquinodimethane (TCNQ) as electron acceptors. Structural, charge transfer and optical properties of the systems have been studied. The D-A pairs then has been considered inside a macrocycle (cucurbit[8]uril) cavity and Naph-Diimide and TTF-Diimide pairs have been shown to exhibit changes in their structures and orientations, TTF-TCNQ pair does not show any significant structural change. Our work suggests that these changes in structures or orientations are result of electronic repulsion between the keto group oxygen atoms and it can lead to tuning of charge transfer and optical properties of the systems.

  14. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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

  16. 78 FR 52548 - The National Children's Study, Vanguard (Pilot) Study Proposed Collection; 60-day Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-23

    ... HUMAN SERVICES National Institutes of Health The National Children's Study, Vanguard (Pilot) Study... Children's Study, Vanguard (Pilot) Study, 0925-0593, Expiration 8/31/2014--Revision, Eunice Kennedy Shriver... activities for the NCS Vanguard Study and receive a renewal of the Vanguard Study clearance. The NCS...

  17. 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

  18. 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

  19. The taunting of parentally bereaved children: an exploratory study.

    PubMed

    Cain, Albert C; LaFreniere, Lucas S

    2015-01-01

    This exploratory study addresses the rarely mentioned, minimally investigated topic of peer taunting of parentally bereaved children. It suggests that social support cannot be adequately conceptualized or measured on an essentially one-dimensional scale from high to low support. The data are derived from lengthy semistructured transcribed research interviews of bereaved children. Using conservative criteria, 7 of the 35 children were found to have experienced direct, raw taunting about their loss. The varied forms of taunting experienced are described, as well as a range of victim reactions. Suggestions of foci for future research are presented. PMID:25581438

  20. 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…

  1. 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.

  2. 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.

  3. 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...

  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 Measurements in Japan Environment and Children's Study.

    PubMed

    Nakayama, Shoji

    2016-01-01

    The Japan Ministry of the Environment is conducting a large-scale birth cohort study called the Japan Environment and Children's Study (JECS), which involves 100000 mother-child pairs. Mothers are enrolled during pregnancy, and their children are followed up and studied until they reach the age of 13 years. The JECS started recruiting mothers in January 2011 and completed the registration of more than 103000 mothers in March 2014. The National Institute for Environmental Studies takes the lead in the study programming and implementation in cooperation with the National Centre for Child Health and Development and 15 Regional Centres that reach out to the study participants. In the study, the effects of environmental factors on children's health and development are investigated. The environment in this study is defined not only as air, soil, water, and indoor environments but also as various chemical substances, physical conditions, socioeconomic factors, psychological conditions, lifestyles and community situations. Mothers' and children's exposures to these environmental factors are measured through chemical analyses of biospecimens collected during pregnancy and after birth, questionnaires and computer modelling. The homes of the randomly selected participants (5000) are visited to measure the concentrations of volatile organic compounds, nitrogen and sulphuric oxides and particulate matter. Vacuum dust samples are also collected for chemical analysis. All these data will be combined with the information collected by the dwelling unit observation to assess the exposure of children aged 1.5 and 3 years. PMID:27252056

  7. 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).

  8. 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.

  9. 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

  10. [Street food among children: a study in north Tunisia].

    PubMed

    Neffati, Larbi; Ridha, Hamza; Kolsteren, Patrick; Hilderbrand, Katherine

    2004-01-01

    As urbanization increases in Tunisia, eating meals outside the home is becoming more frequent. Children are prime consumers for the fast food sold in the streets. Neither their nor their parents' attitude towards street food is well documented as yet. This study was conducted in the city of Bizerte in February 1998. Its aim was to gather information about street food and parents' and children's attitudes towards it to help organize educational sessions with the children, parents, teachers, and vendors. The study interviewed 421 primary school children, ranging in age from 6 to 15 years (mean age: 10 years), from 24 schools. Half received pocket money, a percentage that did not differ by sex. Three quarters of the children used more than 75% of their pocket money to buy street food. The items bought most frequently were candy (27.2%), sandwiches (23.9%), pastries (23.9%), sunflower seeds and peanuts (21%), and either pizza, chocolate, or cheese (20.3%); the largest proportion of money was spent on sandwiches. In more than half the cases (55.7% of the children), the main motivation for buying street food was either to replace or fill out a meal at home, with sandwiches or pastries. The parents' monthly income did not influence the children's purchasing behavior, but the rhythm of receiving pocket money did. Most children were satisfied with the nutritional and hygienic quality of the food available, but their opinion of this quality as well as the reasons for buying the food and the prices spent on it differed considerably from that of their parents. This study highlights the important role of street foods in the daily diet of schoolchildren and the need for appropriate nutrition education in primary schools. PMID:15217744

  11. Impact of nutrition messages on children's food choice: pilot study.

    PubMed

    Bannon, Katie; Schwartz, Marlene B

    2006-03-01

    This pilot study tested the influence of nutrition message framing on snack choice among kindergarteners. Three classrooms were randomly assigned to watch one of the following 60s videos: (a) a gain-framed nutrition message (i.e. the positive benefits of eating apples) (n=14); (b) a loss-framed message (i.e. the negative consequences of not eating apples) (n=18); or (c) a control scene (children playing a game) (n=18). Following this, the children were offered a choice between animal crackers and an apple for their snack. Among the children who saw one of the nutrition message videos, 56% chose apples rather than animal crackers; in the control condition only 33% chose apples. This difference was statistically significant (chi2=7.56, p<0.01). These results suggest that videos containing nutritional messages may have a positive influence on children's short-term food choices. PMID:16442667

  12. A Comparative Study of Stress Profiles in Mothers of Children with Autism and Those of Children with Down's Syndrome

    ERIC Educational Resources Information Center

    Pisula, Ewa

    2007-01-01

    Background: The purpose of the present study was to determine the stress in mothers whose children have autism and to compare it with the stress in mothers whose children have Down's syndrome. Method: Fifty mothers whose children had autism (n = 25) or Down's syndrome (n = 25) completed the Questionnaire on Resources and Stress (QRS) and answered…

  13. 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...

  14. 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.

  15. 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.

  16. 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. PMID:24593615

  17. 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.

  18. 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.

  19. Social Studies through Children's Literature: An Integrated Approach.

    ERIC Educational Resources Information Center

    Fredericks, Anthony D.

    This teacher's handbook, organized in two parts, gives theoretical support for integrating social studies and literature disciplines and serves as an instructional guide for classroom use. Part 1, "Children's Literature in the Social Studies Curriculum," provides a philosophical background for integrating social studies and whole language across…

  20. Quantum Monte Carlo study of charged transition-metal organometallic cluster systems

    NASA Astrophysics Data System (ADS)

    Tokar, Kamil; Derian, Rene; Stich, Ivan

    2015-03-01

    Using accurate fixed-node quantum Monte Carlo (QMC) methods we study 1D clusters formed by transition metal atoms separated by benzene molecules (TMBz), both positively and negatively charged. TMBz are among the most important π-bonded organometallics, which, however, often require charged states for experimental studies. We have performed a systematic study of ground-sate spin multiplets, ionization potentials, electron affinities, and dissociation energies of vanadium-benzene cationic and anionic half- and full-sandwiches. By comparison of QMC and DFT results, we find a very strong impact of electronic correlation on properties of these systems, such as dissociation energies, where ~1 eV energy corrections are found. In particular, the anions are unstable at the DFT level and are stabilized only at the QMC level after sophisticated optimization of the trial wavefunction. Supported by APVV-0207-11 and VEGA (2/0007/12) projects.

  1. Cytokines and other immunological biomarkers in children's environmental health studies

    PubMed Central

    Duramad, Paurene; Tager, Ira B.; Holland, Nina T.

    2007-01-01

    Environmental exposures (e.g. pesticides, air pollution, and environmental tobacco smoke) during prenatal and early postnatal development have been linked to a growing number of childhood diseases including allergic disorders and leukemia. Because the immune response plays a critical role in each of these diseases, it is important to study the effects of toxicants on the developing immune system. Children's unique susceptibility to environmental toxicants has become an important focus of the field of immunotoxicology and the use of immune biomarkers in molecular epidemiology of children's environmental health is a rapidly expanding field of research. In this review, we discuss how markers of immune status and immunotoxicity are being applied to pediatric studies, with a specific focus on the various methods used to analyze T-helper-1/2 (Th1/Th2) cytokine profiles. Furthermore, we review recent data on the effects of children's environmental exposures to volatile organic compounds, metals, and pesticides on Th1/Th2 cytokine profiles and the associations of Th1/Th2 profiles with adverse health outcomes such as pediatric respiratory diseases, allergies, cancer and diabetes. Although cytokine profiles are increasingly used in children's studies, there is still a need to acquire distribution data for different ages and ethnic groups of healthy children. These data will contribute to the validation and standardization of cytokine biomarkers for future studies. Application of immunological markers in epidemiological studies will improve the understanding of mechanisms that underlie associations between environmental exposures and immune-mediated disorders. PMID:17624696

  2. Study of Optimal Perimetric Testing in Children (OPTIC): Feasibility, Reliability and Repeatability of Perimetry in Children

    PubMed Central

    Patel, Dipesh E.; Cumberland, Phillippa M.; Walters, Bronwen C.; Russell-Eggitt, Isabelle; Rahi, Jugnoo S.

    2015-01-01

    Purpose To investigate feasibility, reliability and repeatability of perimetry in children. Methods A prospective, observational study recruiting 154 children aged 5–15 years, without an ophthalmic condition that affects the visual field (controls), identified consecutively between May 2012 and November 2013 from hospital eye clinics. Perimetry was undertaken in a single sitting, with standardised protocols, in a randomised order using the Humphrey static (SITA 24–2 FAST), Goldmann and Octopus kinetic perimeters. Data collected included test duration, subjective experience and test quality (incorporating examiner ratings on comprehension of instructions, fatigue, response to visual and auditory stimuli, concentration and co-operation) to assess feasibility and reliability. Testing was repeated within 6 months to assess repeatability. Results Overall feasibility was very high (Goldmann=96.1%, Octopus=89% and Humphrey=100% completed the tests). Examiner rated reliability was ‘good’ in 125 (81.2%) children for Goldmann, 100 (64.9%) for Octopus and 98 (63.6%) for Humphrey perimetry. Goldmann perimetry was the most reliable method in children under 9 years of age. Reliability improved with increasing age (multinomial logistic regression (Goldmann, Octopus and Humphrey), p<0.001). No significant differences were found for any of the three test strategies when examining initial and follow-up data outputs (Bland-Altman plots, n=43), suggesting good test repeatability, although the sample size may preclude detection of a small learning effect. Conclusions Feasibility and reliability of formal perimetry in children improves with age. By the age of 9 years, all the strategies used here were highly feasible and reliable. Clinical assessment of the visual field is achievable in children as young as 5 years, and should be considered where visual field loss is suspected. Since Goldmann perimetry is the most effective strategy in children aged 5–8 years and this

  3. 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. PMID:26561889

  4. 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. PMID:18576965

  5. Bacterial study of clean intermittent catheterisation in children.

    PubMed

    Taylor, C E; Hunt, G M; Matthews, I G

    1986-02-01

    Deterioration of the upper urinary tract is exceptional in children on clean intermittent catheterisation for neuropathic incontinence and is found only in those with pre-existing renal damage. This report describes a bacteriological study of 24 children, of whom 10 had renal damage and 14 did not have renal damage before clean intermittent catheterisation began. Boric acid was added as a preservative to samples of urine in preference to the use of dip-slides because it preserves pus cells as well as bacteria. The incidence of bacteriuria in the two groups was similar (78% of samples from those with, and 72% of samples from those without, pre-existing renal damage). The groups differed in that the urine of children in the group with pre-existing renal damage yielded organisms other than Escherichia coli more than twice as often as did the urine of those children without renal damage. Moreover, the children with pre-existing renal damage were more likely to have fever with urinary tract infection and some of them showed frequent changes of organisms in the urine. Whatever organism was present, however, children in the group with renal damage more often had heavy pyuria. PMID:3947858

  6. A Comparative Study of Leptospirosis and Dengue in Thai Children

    PubMed Central

    Libraty, Daniel H.; Myint, Khin S. A.; Murray, Clinton K.; Gibbons, Robert V.; Mammen, Mammen P.; Endy, Timothy P.; Li, Wenjun; Vaughn, David W.; Nisalak, Ananda; Kalayanarooj, Siripen; Hospenthal, Duane R.; Green, Sharone; Rothman, Alan L.; Ennis, Francis A.

    2007-01-01

    Background Leptospirosis is an emerging zoonosis that is often under-recognized in children and commonly confused with dengue in tropical settings. An enhanced ability to distinguish leptospirosis from dengue in children would guide clinicians and public health personnel in the appropriate use of limited healthcare resources. Methodology/Principal Findings We conducted a prospective, hospital-based, study of children with acute febrile illnesses and dengue in Thailand. Among the children without dengue, we identified those with leptospirosis using anti-leptospira IgM and microscopic agglutination titers in paired acute and convalescent blood samples. We then performed a case-control comparison of symptoms, signs, and clinical laboratory values between children with leptospirosis and dengue. In a semi-rural region of Thailand, leptospirosis accounted for 19% of the non-dengue acute febrile illnesses among children presenting during the rainy season. None of the children with leptospirosis were correctly diagnosed at the time of hospital discharge, and one third (33%) were erroneously diagnosed as dengue or scrub typhus. A predictive model to distinguish pediatric leptospirosis from dengue was generated using three variables: the absolute neutrophil count, plasma albumin, and aspartate aminotransferase levels in the first 72 hours of illness. Conclusions/Significance Unrecognized leptospirosis can be a significant cause of “dengue-like” febrile illness in children. Increased awareness of pediatric leptospirosis, and an enhanced ability to discriminate between leptospirosis and dengue early in illness, will help guide the appropriate use of healthcare resources in often resource-limited settings. PMID:18160980

  7. Self-consistent simulation studies of periodically focused intense charged-particle beams

    NASA Astrophysics Data System (ADS)

    Chen, C.; Jameson, R. A.

    1995-09-01

    A self-consistent two-dimensional model is used to investigate intense charged-particle beam propagation through a periodic solenoidal focusing channel, particularly in the regime in which there is a mismatch between the beam and the focusing channel. The present self-consistent studies confirm that mismatched beams exhibit nonlinear resonances and chaotic behavior in the envelope evolution, as predicted by an earlier envelope analysis [C. Chen and R. C. Davidson, Phys. Rev. Lett. 72, 2195 (1994)]. Transient effects due to emittance growth are studied, and halo formation is investigated. The halo size is estimated. The halo characteristics for a periodic focusing channel are found to be qualitatively the same as those for a uniform focusing channel. A threshold condition is obtained numerically for halo formation in mismatched beams in a uniform focusing channel, which indicates that relative envelope mismatch must be kept well below 20% to prevent space-charge-dominated beams from developing halos.

  8. Photoelectric studies of the transmembrane charge transfer reactions in photosystem I pigment-protein complexes.

    PubMed

    Semenov, Alexey Yu; Mamedov, Mahir D; Chamorovsky, Sergey K

    2003-10-23

    The results of studies of charge transfer in cyanobacterial photosystem I (PS I) using the photoelectric method are reviewed. The electrogenicity in the PS I complex and its interaction with natural donors (plastocyanin, cytochrome c(6)), natural acceptors (ferredoxin, flavodoxin), or artificial acceptors and donors (methyl viologen and other redox dyes) were studied. The operating dielectric constant values in the vicinity of the charge transfer carriers in situ were calculated. The profile of distribution of the dielectric constant along the PS I pigment-protein complex (from plastocyanin or cytochrome c(6) through the chlorophyll dimer P700 to the acceptor complex) was estimated, and possible mechanisms of correlation between the local dielectric constant and electron transfer rate constant were discussed. PMID:14572628

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

    SciTech Connect

    Zanni, Martin T.

    1999-12-17

    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.

  10. Study of Selected Children in Head Start Planned Variation, 1969-1970. First Year Report: 3 - Case Studies of Children.

    ERIC Educational Resources Information Center

    Dittmann, Laura L.; And Others

    To test the feasibility of using case study techniques in national evaluations, the case study approach was used to study the experiences of a boy and a girl in each of eight Head Start curricular models and two children in a classroom not under the sponsorship of a program developer. Teachers and mothers were also interviewed. The purpose of the…

  11. In-situ Studies of Highly Charged Ions at the LLNL EBIT

    SciTech Connect

    Beiersdorfer, P

    2001-08-16

    The properties of highly charged ions and their interaction with electrons and atoms is being studied in-situ at the LLNL electron beam ion traps, EBIT-II and SuperEBIT. Spectroscopic measurements provide data on electron-ion and ion-atom interactions as well as accurate transition energies of lines relevant for understanding QED, nuclear magnetization, and the effects of relativity on complex, state-of-the-art atomic calculations.

  12. Study of geodesic motion in a (2 +1 )-dimensional charged BTZ black hole

    NASA Astrophysics Data System (ADS)

    Soroushfar, Saheb; Saffari, Reza; Jafari, Afsaneh

    2016-05-01

    The purpose of this study is to derive the equation of motion for geodesics in the vicinity of the spacetime of a (2 +1 )-dimensional charged BTZ black hole. In this paper, we solve geodesics for both massive and massless particles in terms of Weierstrass elliptic and Kleinian sigma hyperelliptic functions. Then we determine different trajectories of motion for particles in terms of conserved energy and angular momentum and also with effective potential.

  13. 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.

  14. Study of charge-phase diagrams for coupled system of Josephson junctions

    NASA Astrophysics Data System (ADS)

    Hamdipour, M.; Shukrinov, Y. U. M.

    2010-11-01

    Dynamics of stacked intrinsic Josephson junctions (IJJ) in the high-Tc superconductors is theoretically investigated. We calculate the current-voltage characteristics (CVC) of IJJ and study the breakpoint region on the outermost branch of the CVC for the stacks with 9 IJJ. A method for investigation of the fine structure in CVC of IJJ based on the recording the "phase-charge" diagrams is suggested. It is demonstrated that this method reflects the main features of the breakpoint region.

  15. 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...

  16. 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…

  17. Reading and Visual Search: A Developmental Study in Normal Children

    PubMed Central

    Seassau, Magali; Bucci, Maria-Pia

    2013-01-01

    Studies dealing with developmental aspects of binocular eye movement behaviour during reading are scarce. In this study we have explored binocular strategies during reading and during visual search tasks in a large population of normal young readers. Binocular eye movements were recorded using an infrared video-oculography system in sixty-nine children (aged 6 to 15) and in a group of 10 adults (aged 24 to 39). The main findings are (i) in both tasks the number of progressive saccades (to the right) and regressive saccades (to the left) decreases with age; (ii) the amplitude of progressive saccades increases with age in the reading task only; (iii) in both tasks, the duration of fixations as well as the total duration of the task decreases with age; (iv) in both tasks, the amplitude of disconjugacy recorded during and after the saccades decreases with age; (v) children are significantly more accurate in reading than in visual search after 10 years of age. Data reported here confirms and expands previous studies on children's reading. The new finding is that younger children show poorer coordination than adults, both while reading and while performing a visual search task. Both reading skills and binocular saccades coordination improve with age and children reach a similar level to adults after the age of 10. This finding is most likely related to the fact that learning mechanisms responsible for saccade yoking develop during childhood until adolescence. PMID:23894627

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    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.

  19. Study of space-charge dependence on IBF for GEM and Micromegas detectors

    NASA Astrophysics Data System (ADS)

    Yukawa, Kentaro; Hamagaki, Hideki; Gunji, Taku; Yamaguchi, Yorito; Terasaki, Kohei

    2014-09-01

    The MWPC is widely used in a Time Projection Chamber (TPC). To prevent ions created around amplification region from back drifting into the drift space, gating grid system is widely used in the TPC. However, the data taking rate is limited by the operation of the gating grid and the TPC with gating grid system cannot be suitable for the high rate experiments. Micor-Pattern Gaseous Detectors (MPGD) are the possible solutions to overcome the high rate limitations. GEM and Micromegas can absorb positive ions on its electrode or mesh and can reduce the ion backflow into the drift space. In this study, we aim to evaluate performance of ion back flow suppression of GEM and Micromegas detector as a function of space-charge density. We also did the simulation studies using Garfield + + to assess the reproducibility of the space-charge density dependence of the ion back flow obtained in the measurement. In this talk, we will report the overall performances (space-charge density and field dependences of the ion backflow) of GEM and micromegas detectors studied in the measurements and simulations.

  20. Rorschach Responses of Sexually Abused Children: An Exploratory Study.

    ERIC Educational Resources Information Center

    Clinton, Gregory T.; Jenkins-Monroe, Valata

    1994-01-01

    Using archival data, this study compared Rorschach protocols of 94 sexually abused children to the Exner norms in order to determine the potential usefulness of the Rorschach test in the area of child abuse assessment and treatment. Of the 18 Rorschach variables studied, 17 significantly distinguished at least one subject group from the norms.…

  1. 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 elements,…

  2. FOLLOW UP STUDY OF CHILDREN WITH DEVELOPMENTAL DISABILITIES

    EPA Science Inventory

    The Follow-Up Study involves locating and interviewing a group of young adults who, as 10-year-old children, were included in the Metropolitan Atlanta Developmental Disabilities Study, an investigation of the prevalence and risk factors for developmental disabilities that was con...

  3. A Periodical Use Study at Children's Hospital of Michigan.

    ERIC Educational Resources Information Center

    Smith, Joan M. B.

    A periodicals use study was conducted in the Medical Library of Children's Hospital, a pediatric teaching hospital, during the six month period from September 1, 1967 to February 29, 1968. Results of the study showed that the three kinds of periodical use--circulation, reading room use, and interlibrary loan--have similar but not identical…

  4. 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 express their…

  5. CHILD DEVELOPMENT STUDY (NCDS): CHILDREN OF THE BRITISH NCDS

    EPA Science Inventory

    The National Child Development Study (NCDS) is one of Britain's birth cohort studies, surveying all the children born in U.K. in a week of March 1958 (a complete enumeration, not a sample). They have been re-interviewed several times over the past forty years: first, at the time ...

  6. Research on Mathematical Thinking of Young Children: Six Empirical Studies.

    ERIC Educational Resources Information Center

    Steffe, Leslie P., Ed.

    This volume includes reports of six studies of the thought processes of children aged four through eight. In the first paper Steffe and Smock outline a model for learning and teaching mathematics. Six reports on empirical studies are then presented in five areas of mathematics learning: (1) equivalence and order relations; (2) classification and…

  7. Study on effect of charge on inertial particle motion in turbulence by using holographic particle tracking velocimetry

    NASA Astrophysics Data System (ADS)

    Yang, Fan

    Particles in turbulence flows, either natural or artificial, can be charged. According to the previous research, electrical charge on particles has an influence on both rain enhancement and particle clustering in turbulent flow. Due to the Lorenz effect of unipolar or bipolar charged particles, particles tend to attract or repel to each other. Moreover, it is well known that electrical field exists in the atmosphere that has an effect on charged particles, especially droplets. As a result, the dynamic behaviors of charged particles can be rather different from uncharged particles, which, to date, are not systematically studied yet. In order to systematically investigate the charged particles, we developed a method involving holographic particle tracking velocimetry (HPTV) technique to study the kinetic behavior of charged particles in flow. Theoretical analysis was also carried out to correlate kinetic behavior of particles and charge amount on them. This thesis also validated the feasibility of this method. The results of the validation experiment show that this method is capable to measure the velocity and acceleration of particles. By means of the second-order polynomial regression of particles' motion, the average acceleration, initial position and initial velocity of particles were obtained. With the mathematical model of a product of two normally distributed variables, the error bounds in measurement of particle kinetics can be acquired. Therefore, combining with the electrical field and diameter range of particles, we can quantitatively study the dynamic behavior of charged particles in flow. In order to verify this, some experiments were designed and performed. We applied this method to quantitatively measure the behavior of particles to acquire the charge amount on particles from an enclosed chamber used in turbulence experiments. The result showed that although the charge amount was very low, most particles were charged with positive charge in the

  8. Treatment of vulvar lichen sclerosus with topical corticosteroids in children: a study of 72 children.

    PubMed

    Casey, G A; Cooper, S M; Powell, J J

    2015-04-01

    Treatment of vulvar lichen sclerosus (VLS) in children by topical corticosteroids gives control of symptoms and some resolution of physical signs, but large studies are limited. We report the largest study of 72 prepubertal girls with VLS, 62 of whom were prospectively treated with daily application of an ultrapotent topical corticosteroid (UPTC), clobetasol propionate 0.05% ointment, for 3 months, with a follow-up period of 4-8 years [the remaining 10 patients responded to mild to moderate potency topical corticosteroids (MPTCs)]. The results were compared with a retrospective study of 31 prepubertal girls with VLS treated with MPTCs. MPTCs led to symptom clearance in 32.2% of patients, whereas UPTC led to symptom clearance in 72.6% of patients. Improvement in clinical signs following UPTC occurred in 90.3% of children at 3 months, with total resolution of clinical signs occurring in 29.2% at the 4-year follow-up or at puberty. No serious adverse effects occurred with UPTC treatment. In children with VLS, UPTCs relieve symptoms, resolve signs and possibly prevent scarring. UPTCs should therefore be the treatment of choice for VLS in children. PMID:25477189

  9. Nonlinear vibrational spectroscopic studies of molecular interaction and charging behavior at solid/liquid interfaces

    NASA Astrophysics Data System (ADS)

    Zhang, Luning

    Solid-liquid interfaces have been the focus of different communities of scientists due to its importance in industrial applications and chemical processes in nature. Molecular interactions and surface charges affect the physicochemical properties of these interfaces and a thorough understanding is still lacking now. This thesis describes our work in studying several model solid-liquid interfaces using sum-frequency vibrational spectroscopy. Through the studies of interfacial vibrational spectra, we hope to gain better understanding of molecular interactions in competitive adsorption process and also surface charging behavior at different pH and salt concentrations. We start by studying alcohol-water mixture and the adsorption behavior at both hydrophilic and hydrophobic surfaces. In both cases, alcohol adsorbs preferentially from water. The tendency for water to form strong hydrogen-bonding network is the driving force for preferential adsorption of alcohol. We proposed two different interfacial molecular structures on hydrophilic and hydrophobic surfaces. We move on to study the interaction of pure water with a solid surface. Single crystal alumina is used as a model system. At different pH, the surface can undergo protonation and deprotonation reactions and accumulates surface charge. Both the hydrogen-bonding with water and the surface field created by surface charge can affect interfacial water structure. Combining the information obtained with intensity and phase spectra, we find water molecules have two types of bonding within the interfacial layer: weakly hydrogen-bonded species near 3450 cm-1 that does not flip with switching surface charge, and strongly hydrogen-bonded species at 3200 cm-1 that readily flips with switching surface field. One other system we have studied is nanoporous silica-water interface. We found that signal from interfacial water is reduced due to the porous nature of the film. The water spectral features tell us about the interfacial

  10. Nanoscale charge transport in cytochrome c3/DNA network: Comparative studies between redox-active molecules

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Harumasa; Che, Dock-Chil; Hirano, Yoshiaki; Suzuki, Masayuki; Higuchi, Yoshiki; Matsumoto, Takuya

    2015-09-01

    The redox-active molecule of a cytochrome c3/DNA network exhibits nonlinear current-voltage (I-V) characteristics with a threshold bias voltage at low temperature and zero-bias conductance at room temperature. I-V curves for the cytochrome c3/DNA network are well matched with the Coulomb blockade network model. Comparative studies of the Mn12 cluster, cytochrome c, and cytochrome c3, which have a wide variety of redox potentials, indicate no difference in charge transport, which suggests that the conduction mechanism is not directly related to the redox states. The charge transport mechanism has been discussed in terms of the newly-formed electronic energy states near the Fermi level, induced by the ionic interaction between redox-active molecules with the DNA network.

  11. Studying electromagnetic interference spectrum in antenna under aircraft radome using models with artificial charged aerosol clouds

    NASA Astrophysics Data System (ADS)

    Temnikov, A. G.; Gilyazov, M. Z.; Matveev, D. A.; Voronkova, A. Yu.; Chernenskii, L. L.; Orlov, A. V.

    2011-09-01

    The spectrum of electromagnetic interference that is induced by discharges in an antenna arranged under an aircraft radome in an artificial charged aqueous aerosol cloud has been experimentally studied. It is established that, among different possible variants of lightning-arrest radomes, the minimum level of the spectral density of interference signals in the antenna is provided by vertical stripe electrodes on the radome surface. The maximum characteristic frequencies of signals in a model spherical antenna are several times lower than those in model lightning diverters, while the flat model antennas of disk or rectangular shapes exhibit the opposite trend. It has been suggested that a significant role in determining the characteristics of the electromagnetic interference spectrum in weather radar antennas is played by currents of discharges generated by charges accumulated on the dielectric radome surface.

  12. 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.

  13. Study of charge symmetry breaking in dd collisions with WASA-at-COSY

    SciTech Connect

    Wronska, Aleksandra

    2011-10-24

    Charge symmetry is an approximate symmetry of the strong interaction. Studies of its breaking can yield information on the u and d quark mass difference. A theoretical collaboration is currently working on the description of charge symmetry breaking mechanisms for dd{yields}{alpha}{pi}{sup 0} and np{yields}d{pi}{sup 0} within Chiral Perturbation Theory, using the data from TRI-UMF and IUCF. One of the items in the program of the WASA-at-COSY collaboration is to extend the data base for the dd{yields}{alpha}{pi}{sup 0} reaction to higher energies, which would allow the extraction of the information on the p-wave. Status of the analysis of experimental data along with the preliminary results from the pilot run will be presented here.

  14. 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.

  15. 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.

  16. Synthesis and spectroscopic studies of the charge transfer complexes of 2- and 3-aminopyridine

    NASA Astrophysics Data System (ADS)

    Mostafa, Adel; Bazzi, Hassan S.

    2009-09-01

    The interactions of the electron donors 2-aminopyridine (2APY) and 3-aminopyridine (3APY) with the π-acceptors tetracyanoethylene (TCNE), 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), 2-chloro-1,3,5-trinitrobenzene (picryl chloride, PC), and 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil) were studied spectrophotometrically in chloroform at room temperature. The electronic and infrared spectra of the formed molecular charge transfer (CT) complexes were recorded. Photometric titration showed that the stoichiometries of the reactions were fixed and depended on the nature of both the donor and the acceptor. The molecular structures of the CT-complexes were, however, independent of the position of the amino group on the pyridine ring and were formulated as [(APY)(TCNE)], [(APY)(DDQ)], [(APY)(PC)], and [(APY) (chloranil)]. The formation constants ( KCT), charge transfer energy ( ECT) and molar extinction coefficients ( ɛCT) of the formed CT-complexes were obtained.

  17. Solution, surface, and single molecule platforms for the study of DNA-mediated charge transport

    PubMed Central

    Muren, Natalie B.; Olmon, Eric D.; Barton, Jacqueline K.

    2012-01-01

    The structural core of DNA, a continuous stack of aromatic heterocycles, the base pairs, which extends down the helical axis, gives rise to the fascinating electronic properties of this molecule that is so critical for life. Our laboratory and others have developed diverse experimental platforms to investigate the capacity of DNA to conduct charge, termed DNA-mediated charge transport (DNA CT). Here, we present an overview of DNA CT experiments in solution, on surfaces, and with single molecules that collectively provide a broad and consistent perspective on the essential characteristics of this chemistry. DNA CT can proceed over long molecular distances but is remarkably sensitive to perturbations in base pair stacking. We discuss how this foundation, built with data from diverse platforms, can be used both to inform a mechanistic description of DNA CT and to inspire the next platforms for its study: living organisms and molecular electronics. PMID:22850865

  18. 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

  19. Charge carrier dynamics in bulk MoS2 crystal studied by transient absorption microscopy

    NASA Astrophysics Data System (ADS)

    Kumar, Nardeep; He, Jiaqi; He, Dawei; Wang, Yongsheng; Zhao, Hui

    2013-04-01

    We report a transient absorption microscopy study of charge carrier dynamics in bulk MoS2 crystals at room temperature. Charge carriers are injected by interband absorption of a 555-nm pulse, and probed by measuring differential reflection of a time-delayed and spatially scanned 660-nm pulse. We find an intervalley transfer time of about 0.35 ps, an energy relaxation time of hot carriers on the order of 50 ps, and a carrier lifetime of 180 ± 20 ps. By monitoring the spatiotemporal dynamics of carriers, we obtained a diffusion coefficient of thermalized electrons of 4.2 ± 0.5 cm2/s, corresponding to a mobility of 170 ± 20 cm2/Vs. We also observed a time-varying diffusion coefficient of hot carriers.

  20. Nonadiabatic couplings and charge transfer study in H + CS+ collision using time-dependent quantum dynamics

    NASA Astrophysics Data System (ADS)

    Kaur, Rajwant; Dhilip Kumar, T. J.

    2015-11-01

    Experiments have reported the high stability of HCS+ ion and inhibit to decompose over the range of collision energies. In this study, the various energy transfer channels of atomic H collision with CS+ molecular ion has been performed by ab initio computations at the multireference configuration interaction/aug-cc-pVQZ level of theory. The ground and several low-lying excited electronic state potential energy surfaces in three different molecular orientations, namely, two collinear configurations with, (1) H approaching the S atom (γ = 0°), (2) H approaching the C atom (γ = 180°) and one perpendicular configuration, (3) H approaching the centre of mass of CS (γ = 90°) with the diatom fixed at the equilibrium bond length, have been obtained. Nonadiabatic effects with Landau-Zener coupling leading to avoided crossings are observed between the ground- and the first-excited states in γ = 90° orientation, and also between the first- and second-excited states in γ = 180° orientation. Quantum dynamics have been performed to study the charge transfer using time-dependent wave packet method on the diabatic potential energy surfaces. The probability of charge transfer is found to be highest with 42% in γ = 180°. The high charge transfer probability result in the formation of H+ + CS channel which ascertains the high stability of HCS+ ion.

  1. Theoretical Study on Charge Transport Properties of Intra- and Extra-Ring Substituted Pentacene Derivatives.

    PubMed

    Fan, Jian-Xun; Chen, Xian-Kai; Zhang, Shou-Feng; Ren, Ai-Min

    2016-04-21

    A series of pentacene derivatives, halogen-substituted and thiophene- and pyridine-substituted, have been studied with a focus on the electronic properties and charge transport properties using density functional theory and classical Marcus charge-transfer theory. The transport properties of holes and electrons have been studied to get insight into the effect of halogenation and heteroatom substitution on transport and injection of charge carriers. The calculation results revealed that fluorination and chlorination can effectively lower the lowest unoccupied molecular orbital (LUMO) level, modulate the hole and electron reorganization energy, improve the stacking mode of the crystal structure, and enhance the ambipolar characteristic. Chlorination gives a better ambipolar characteristic. On the basis of halogen substitution, the substitution of terminal benzene ring of triisopropyl-silylethynyl-pentacene (TIPS-PEN) by a thiophene or pyridine will greatly lower the LUMO level and improve the stacking mode, leading to more suitable ambipolar materials. Hence, both intra- and extra-ring substitution are favorable to enhance the ambipolar transport property of TIPS-PEN. PMID:27027319

  2. Studies on hydrogen plasma and dust charging in low-pressure filament discharge

    SciTech Connect

    Kakati, B. Kalita, D.; Kausik, S. S.; Saikia, B. K.; Bandyopadhyay, M.

    2014-08-15

    The effect of working gas pressure and dust charging on electron energy probability function has been studied for hydrogen plasma in a multi-dipole dusty plasma device. A cylindrical Langmuir probe is used to evaluate the plasma parameters and electron energy probability function (EEPF) for different working pressures. For lower energy range (below 10 eV), the EEPF follows a bi-Maxwellian shape at very low pressure (6 × 10{sup −5} mbar), while elevating the working pressure up to ∼2 × 10{sup −3} mbar, the shape of the EEPF transforms into a single Maxwellian. Some dip structures are observed at high energy range (ε > 10 eV) in the EEPF of hydrogen plasma at all the working conditions. In presence of dust particles, it is observed that the shape of the EEPF changes due to the redistribution of the high and low-energy electron populations. Finally, the effect of working pressure on charge accumulation on dust particles is studied with the help of a Faraday cup and electrometer. From the observations, a strong influence of working pressure on plasma parameters, EEPF and dust charging is observed.

  3. 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

  4. 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

  5. Magnetoencephalography in the study of children with autism spectrum disorder.

    PubMed

    Kikuchi, Mitsuru; Yoshimura, Yuko; Mutou, Kouhei; Minabe, Yoshio

    2016-02-01

    Magnetoencephalography (MEG) is a non-invasive neuroimaging technique that provides a measure of cortical neural activity on a millisecond timescale with high spatial resolution. MEG has been clinically applied to various neurological diseases, including epilepsy and cognitive dysfunction. In the past decade, MEG has also emerged as an important investigatory tool in neurodevelopmental studies. It is therefore an opportune time to review how MEG is able to contribute to the study of atypical brain development. We limit this review to autism spectrum disorder (ASD). The relevant published work for children was accessed using PubMed on 5 January 2015. Case reports, case series, and papers on epilepsy were excluded. Owing to their accurate separation of brain activity in the right and left hemispheres and the higher accuracy of source localization, MEG studies have added new information related to auditory-evoked brain responses to findings from previous electroencephalography studies of children with ASD. In addition, evidence of atypical brain connectivity in children with ASD has accumulated over the past decade. MEG is well suited for the study of neural activity with high time resolution even in young children. Although further studies are still necessary, the detailed findings provided by neuroimaging methods may aid clinical diagnosis and even contribute to the refinement of diagnostic categories for neurodevelopmental disorders in the future. PMID:26256564

  6. Age Effects in a Study Abroad Context: Children and Adults Studying Abroad and at Home

    ERIC Educational Resources Information Center

    Llanes, Angels; Munoz, Carmen

    2013-01-01

    This study examines the effects of learning context and age on second language development by comparing the language gains, measured in terms of oral and written fluency, lexical and syntactic complexity, and accuracy, experienced by four groups of learners of English: children in a study abroad setting, children in their at-home school, adults in…

  7. 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…

  8. 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…

  9. 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…

  10. 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…

  11. 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.

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

    PubMed

    Misra, Anuraag; Goswami, A; Sing Babu, P; Srivastava, S; Pandit, V S

    2015-11-01

    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. PMID:26628123

  13. Charge-carrier relaxation in disordered organic semiconductors studied by dark injection: Experiment and modeling

    NASA Astrophysics Data System (ADS)

    Mesta, M.; Schaefer, C.; de Groot, J.; Cottaar, J.; Coehoorn, R.; Bobbert, P. A.

    2013-11-01

    Understanding of stationary charge transport in disordered organic semiconductors has matured during recent years. However, charge-carrier relaxation in nonstationary situations is still poorly understood. Such relaxation can be studied in dark injection experiments, in which the bias applied over an unilluminated organic semiconductor device is abruptly increased. The resulting transient current reveals both charge-carrier transport and relaxation characteristics. We performed such experiments on hole-only devices of a polyfluorene-based organic semiconductor. Modeling the dark injection by solving a one-dimensional master equation using the equilibrium carrier mobility leads to a too-slow current transient, since this approach does not account for carrier relaxation. Modeling by solving a three-dimensional time-dependent master equation does take into account all carrier transport and relaxation effects. With this modeling, the time scale of the current transient is found to be in agreement with experiment. With a disorder strength somewhat smaller than extracted from the temperature-dependent stationary current-voltage characteristics, also the shape of the experimental transients is well described.

  14. 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.

  15. 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.

  16. 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.

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

    DOE PAGESBeta

    Knudsen, Kristian B.; Luntz, Alan C.; Jensen, Søren H.; Vegge, Tejs; Hjelm, Johan

    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. 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. PMID:23411141

  19. Simulation study on the translocation of a partially charged polymer through a nanopore

    NASA Astrophysics Data System (ADS)

    Qian, Hong; Sun, Li-Zhen; Luo, Meng-Bo

    2012-07-01

    The translocation of a partially charged polymer through a neutral nanopore under external electrical field is studied by using dynamic Monte Carlo method on a simple cubic lattice. One monomer in the polymer is charged and it suffers a driving force when it locates inside the pore. Two time scales, mean first passage time τFP with the first monomer restricted to never draw back into cis side and translocation time τ for polymer continuously threading through nanopore, are calculated. The first passage time τFP decreases with the increase in the driving force f, and the dependence of τFP on the position of charged monomer M is in agreement with the theoretical results using Fokker-Planck equation [A. Mohan, A. B. Kolomeisky, and M. Pasquali, J. Chem. Phys. 128, 125104 (2008), 10.1063/1.2868777]. But the dependence of τ on M shows a different behavior: It increases with f for M < N/2 with N the polymer length. The novel behavior of τ is explained qualitatively from dynamics of polymer during the translocation process and from the free energy landscape.

  20. Human paraoxonase polymorphism: Hungarian population studies in children and adults.

    PubMed

    Szabó, I; Róna, K; Czinner, A; Gachályi, B

    1991-06-01

    The paraoxonase phenotype distribution pattern was studied in a Hungarian population of 102 children and 100 adults. All the subjects were of Caucasian origin and are not related. The adult population showed the trimodality in phenotype distribution similar to other European population data. The gene frequencies obtained were statistically not significantly different either. There was no correlation between the activity of serum paraoxonase and activity of cholinesterase, sex, age and body weight. The phenotype distribution was trimodal in the children's population too. There was a significant difference in gene frequency, however, compared to data from adult population. PMID:1651288

  1. Studies of Charged Particle Emission in the Decay of 45Fe

    SciTech Connect

    Miernik, K.; Dominik, W.; Janas, Z.; Pfutzner, M.; Grigorenko, L.; Bingham, C. R.; Czyrkowski, H.; Cwiok, Mikolaj; Darby, Iain; Dabrowski, Ryszard; Ginter, T. N.; Grzywacz, R.; Karny, M.; Korgul, A.; Kusmierz, W.; Liddick, Sean; Rajabali, M. M.; Rykaczewski, Krzysztof Piotr; Stolz, A.

    2008-01-01

    The decay of extremely neutron-deficient isotope 45Fe has been studied by using a new type of gaseous detector in which a technique of optical imaging is used to record tracks of charged particles. The two-proton radioactivity and the -decay channels accompanied by proton(s) emission were clearly identified. For the first time, the angular and energy correlations between two protons emitted from the 45Fe ground-state were measured. The obtained distributions were confronted with predictions of a three-body model. Studies of -decay channels of 45Fe provided first unambiguous evidence for the -delayed three proton emission.

  2. 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...

  3. 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…

  4. 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;…

  5. 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...

  6. Metacognition and Control of Study Choice in Children

    ERIC Educational Resources Information Center

    Metcalfe, Janet; Finn, Bridgid

    2013-01-01

    Middle childhood may be crucial for the development of metacognitive monitoring and study control processes. The first three experiments, using different materials, showed that Grade 3 and Grade 5 children exhibited excellent metacognitive resolution when asked to make delayed judgments of learning (JOLs, using an analogue scale) or binary…

  7. 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:…

  8. 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)

  9. A Factor Analytic Study of Children's Picture Interpretation Behavior.

    ERIC Educational Resources Information Center

    Higgins, Leslie C.

    1978-01-01

    This study focused on the psychological process involved in drawing inferences from pictures. Nineteen reference tests and two tests of picture interpretation behavior were administered to a random sample of 95 children aged 10-12: the Production of Inference Tests (PIT) and the Discovery of Similarities Test (DST). (JEG)

  10. Accountability Study for Trainable Mentally Retarded Children and Youth.

    ERIC Educational Resources Information Center

    Duval County School Board, Jacksonville, FL.

    Twelve teachers of trainable mentally handicapped children participated in a 7 week workshop which revised and expanded a previously developed catalog of behavioral objectives as part of an educational accountability study. Approximately 600 behavioral objectives with accompanying methods, materials, activities, and criterion test items were…

  11. 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…

  12. A Study in Training Nursery Children on Logical Operational Skills.

    ERIC Educational Resources Information Center

    Kincaid, Carolyn; And Others

    Piaget's organismic-developmental theory of intelligence was investigated in this study to determine the effectiveness of training middle class 3 and 4 year olds on two logico-mathematical structures: classification and seriation. Twenty-four children were divided into two main age groups (mean ages: 3 years 8 months; 4 years 5 months). Within…

  13. 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…

  14. Prosodic Processing by Children: An fMRI Study

    ERIC Educational Resources Information Center

    Plante, Elena; Holland, Scott K.; Schmithorst, Vince J.

    2006-01-01

    Prosodic information in the speech signal carries information about linguistic structure as well as emotional content. Although children are known to use prosodic information from infancy onward to assist linguistic decoding, the brain correlates of this skill in childhood have not yet been the subject of study. Brain activation associated with…

  15. Observational Studies of Retarded Children with Multiple Stereotyped Movements.

    ERIC Educational Resources Information Center

    Baumeister, Alfred A.; And Others

    1980-01-01

    Three relatively long-term observational studies, involving seven retarded preschool children, each of whom exhibited multiple stereotypes, were conducted to determine the extent to which the type of activity or setting had any effect upon the rates of stereotyped movements. (Author)

  16. Environmental Influences on Children's Language: A Model and Case Study.

    ERIC Educational Resources Information Center

    Hemmeter, Mary Louise; Kaiser, Ann P.

    1990-01-01

    This paper provides a conceptual model of the language learning environment of young children, incorporating child engagement with the physical environment, contributions of child and caregiver, and caregiver mediation of physical environment. A case study illustrates the impact of a relatively simple home environmental intervention on a…

  17. Children as Teachers: Developmental Studies of Instructional Communication

    ERIC Educational Resources Information Center

    Pratt, Michael W.; And Others

    1977-01-01

    Two studies with elementary and preschool children investigated the effects of varying the perceptual support for speakers on the process of listener-adaptation in communication. An instructional task in which the child taught a peer to play a board game was utilized. (Author/JMB)

  18. 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...

  19. LUNG FUNCTION IN SCHOOL CHILDREN: 1971-1972 CHATTANOOGA STUDY

    EPA Science Inventory

    Previous studies of lung function in children have indicated that decreases in lung function are associated with higher air pollution exposures. For this reason, three quarter second timed forced expiratory volume was chosen as one of the health indicators in the Environmental Pr...

  20. Children's Linguistic Attitudes: A Study and Some Implications.

    ERIC Educational Resources Information Center

    Light, Richard L.

    Linguists and psychologists have disagreed concerning the development and nature of children's social perceptions of others on the basis of speech differences. The present study sought to determine in what ways 8- and 9-year olds from different socioeconomic backgrounds might react to dialect differences. Ninety-two randomly selected 8- and…

  1. 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…

  2. 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...

  3. 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...

  4. Children's Content Interest--A Factor Analytic Study.

    ERIC Educational Resources Information Center

    Feeley, Joan T.

    Recognizing that interest is essential to motivation, this study was designed both to identify and describe the content interest patterns and media preferences (print and television) of middle-grade children and to determine any relationship between these interests and sex, race, or socioeconomic status (SES). An inventory was administered to 250…

  5. Reimagining Development: Possibilities from the Study of Children's Art. Commentary.

    ERIC Educational Resources Information Center

    Wolf, Dennie Palmer

    1997-01-01

    Discusses study of the development of children's drawing as infused with Western cultural values. Suggests that changes are needed in the images used to describe development, especially the use of developmentally ordered stages. Maintains that the light spectrum is the most promising reconceptualization of artistic development because it captures…

  6. Promoting Effective Interviewing of Sexually Abused Children: A Pilot Study

    ERIC Educational Resources Information Center

    Cheung, Monit

    2008-01-01

    Objective: This study is centered on interviewing techniques with alleged child sexual abuse victims who do and do not disclose sexual abuse. Method: Ninety randomly selected videotapes are reviewed, and the interviewing techniques are recorded on a 69-item Child Sexual Abuse Interviewing Skills Instrument. Results: The nondisclosure children are…

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

    PubMed Central

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

    1988-01-01

    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]). PMID:3358419

  8. 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)).

  9. 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…

  10. Optical studies of the charge localization and delocalization in conducting polymers

    NASA Astrophysics Data System (ADS)

    Kim, Youngmin

    A systematic charge transport study on the thermochromism of polyaniline (PAN) doped with a plasticizing dopant, and on a field effect device using conducting poly (3,4-ethylenedioxythiophene) (PEDOT) as its active material, was made at optical (20--45,000 cm-1) frequencies to probe the charge localization and delocalization phenomena and the insulator to metal transition (IMT) in the inhomogeneous conducting polymer system. Temperature dependent reflectance [20--8000 cm -1 (2.5 meV--1eV)] of the PAN sample, together with absorbance and do transport study done by Dr. Pron at the Laboratoire de Physique des Metaux Synthetiques in Grenoble, France, shows spectral weight loss in the infrared region but the reflectance in the very low frequency (below 100 cm-1) remains unaffected. There are two localization transitions. The origin of the 200 K localization transition that affect >˜15% of the electrons is the glass transition emanating from the dopants. The transition principally affects the IR response in the range of 200--8000 cm -1. The low temperature (<75K) localization transition affects the few electrons that provide the high conductivity. It is suggested that these electrons are localized by disorder at the lowest temperature and become delocalized through phonon induced delocalization as the temperature increases to 75K. It is noted that this temperature is typical of a Debye temperature in many organic materials. The thermocromism is attributed to the weak localization to strong localization transition through the glass transition temperature. Below the glass transition temperature (Tg), the lattice is "frozen" in configuration that reduces the charge delocalization and lead to cause increase of strongly localized polarons. Time variation of source-drain current, real-time IR reflectance [20--8000 cm-1 (2.5 meV--1eV)] modulation, and real-time UV/VIS/NIR absorbance [380--2400 nm (0.5--3.3 eV)] modulation were measured to investigate the field induced charge

  11. [Treatment outcome for myelodysplastic syndromes (MDS) obtained by the Polish Children's Leukemia/Lymphoma Study Group].

    PubMed

    Chybicka, A; Kołecki, P; Pietras, W; Bogusławska-Jaworska, J; Wójcik, D; Armata, J; Eliasińska, A; Kowalczyk, J; Jackowska, T; Klus, K; Matysiak, M; Krauze, A; Stefańska, K; Rokicka-Milewska, R; Wiśniewska-Slusarz, H

    1998-02-01

    Fourty children with MDS treated in seven centres of The Polish Children's Leukemia Lymphoma Study Group in period 1975-1998y were included to the study. In 16 children RAEB-T, in 2 CMML in 10 RA and in 12 RAEB were diagnosed. Our and literature data showed that BMT is the best therapy for children with MDS. For children, who don't have a donor for BMT. Roacutan therapy seems to be the most effective. PMID:9686518

  12. Them Children: A Study in Language Learning. Case Studies in Education and Culture Series.

    ERIC Educational Resources Information Center

    Ward, Martha Coonfield

    This is a study of how children in a small community called Rosepoint, in the vicinity of New Orleans, acquire speech. The author provides essential contextualization for her problem, dealing with family composition, life space, means used to control children, and interaction between members of the household. The author made intensive observations…

  13. The self-consistent field study of the adsorption of flexible polyelectrolytes onto two charged nano-objects.

    PubMed

    Tong, Chaohui; Zhu, Yuejin; Zhang, Hongdong; Qiu, Feng; Tang, Ping; Yang, Yuliang

    2011-10-01

    The continuum self-consistent field theory (SCFT) is applied to the study of the adsorption of flexible polyelectrolyte (PE) onto the surfaces of two two-dimensional charged square objects with a constant electric field strength immersed in a weakly charged polyelectrolyte solution. The dependences of the different chain conformations, that is, bridging, loop, tail, and train, and in particular, the bridging chain conformation, on various system parameters (the charge fraction of the PE chains, the surface charge density, the object size, the salt concentration, etc.) are investigated. The efficient multigrid method is adopted to numerically solve the modified diffusion equation and the Poisson equation. It is found that the thickness L(B) of the boundary layer of the adsorbed PE chains is independent of the chain length and scales with the surface charge density σ and the fraction of charges on PE chains α(P) as L(B) ~ σ(-0.36) and L(B) ~ α(P)(-0.36), respectively. Simulation results reveal that the total amount of bridging chain conformation in the system scales linearly with respect to the size of the charge objects and scales linearly with the chain length in the long polymer chain regime. Simulation results reveal that the total amount of the bridging chain conformation in the system scales with the charge fraction of PE chains as a power law and the scaling exponent is dependent on all of the other system parameters. Simulation results show that the total amount of charges on the adsorbed chains in the system can overcompensate the surface charges for relatively long chains with high charge fractions. PMID:21888311

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

    PubMed

    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. PMID:25362412

  15. 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

  16. 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.

  17. Improvement of Fine Motor Skills in Children with Visual Impairment: An Explorative Study

    ERIC Educational Resources Information Center

    Reimer, A. M.; Cox, R. F. A.; Nijhuis-Van der Sanden, M. W. G.; Boonstra, F. N.

    2011-01-01

    In this study we analysed the potential spin-off of magnifier training on the fine-motor skills of visually impaired children. The fine-motor skills of 4- and 5-year-old visually impaired children were assessed using the manual skills test for children (6-12 years) with a visual impairment (ManuVis) and movement assessment for children (Movement…

  18. Case Studies Using Functional Analysis for Young Children with Behavior Risks.

    ERIC Educational Resources Information Center

    Kamps, Debra M.; And Others

    1995-01-01

    Case studies were conducted of 10 children (ages 4-6) with behavior risks. Hypotheses regarding the function and maintenance of misbehaviors suggested that children received immediate tangible rewards, children received interaction with the teacher, and children received increased attention from adults. Intervention to counter these functions…

  19. Phonological Development in Specific Contexts: Studies of Chinese-Speaking Children. Child Language and Development.

    ERIC Educational Resources Information Center

    Hua, Zhu

    This book examines the phonological development and impairment of Chinese-speaking children. It contains a series of studies of phonological acquisition and development of children in specific contexts (Putonghua or Modern Standard Chinese, the language variety promoted by the Chinese government, and normally developing children, children with…

  20. 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…

  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…

  2. 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.

  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 explores the…

  4. Neural Correlates of Cognitive Reappraisal in Children: An ERP Study

    PubMed Central

    DeCicco, Jennifer M.; Solomon, Beylul; Dennis, Tracy A.

    2011-01-01

    Cognitive emotion regulation strategies, such as reappraising the emotional meaning of events, are linked to positive adjustment and are disrupted in individuals showing emotional distress, like anxiety. The late positive potential (LPP) is sensitive to reappraisal: LPP amplitudes are reduced when unpleasant pictures are reappraised in a positive light, suggesting regulation of negative emotion. However, only one study has examined reappraisal in children using the LPP. The present study examined whether directed reappraisals reduce the LPP in a group of 5- to 7-year-olds, and correlate with individual differences in fear and anxiety. EEG was recorded from 32 typically-developing children via 64 scalp electrodes during a directed reappraisal task. Mothers reported on child anxiety. Fearful behavior was observed. As predicted, LPP amplitudes were larger to unpleasant versus neutral pictures; counter to predictions, the LPP was not sensitive to reappraisal. The degree to which unpleasant versus neutral pictures elicited larger LPPs was correlated with greater anxiety and fear. Results suggest that reappraisal in young children is still developing, but that the LPP is sensitive to individual differences related to fear and anxiety. The utility of the LPP as a measure of cognitive emotion regulation and emotional processing biases in children is discussed. PMID:22163262

  5. Influence of defects on excess charge carrier kinetics studied by transient PC and transient PA

    SciTech Connect

    Feist, H.; Kunst, M.; Swiatkowski, C.

    1997-07-01

    By comparison of transient photoconductivity (TPC) and transient photoinduced absorption (PA) the influence of the density of states in the bandgap on excess charge carrier kinetics is studied for a-Si:H films deposited at different temperatures and for state of the art a-Si:H films in two different states of light soaking. In both series the rising deep defect density leads to an enhancement of electron trapping rather than recombination via deep defects. The samples deposited at temperatures lower than 250 C additionally show a lower effective electron mobility, i.e., a broader conduction band tail.

  6. 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.

  7. Study of charge transfer complexes of menadione (vitamin K3) with a series of anilines.

    PubMed

    Pal, Purnendu; Saha, Avijit; Mukherjee, Asok K; Mukherjee, Dulal C

    2004-01-01

    Menadione (vitamin K(3)) has been shown to form charge transfer complexes with N,N-dimethyl aniline, N,N-dimethyl p-toluidine and N,N-dimethyl m-toluidine in CCl(4) medium. The CT transition energies are well correlated with the ionisation potentials of the anilines. The formation constants of the complexes have been determined at a number of temperatures from which the enthalpies and entropies of formation have been obtained. The formation constants exhibit a very good linear free energy relationship (Hammett) at all the temperatures studied. PMID:14670474

  8. Neutron-induced charged-particle emission studies below 100 MeV at WNR

    SciTech Connect

    Haight, R.C.; Lee, T.M.; Sterbenz, S.M.

    1994-07-01

    Charged-particles produced by neutron bombardment of selected targets with Z=5 through 53 have been studied for neutron energies from 1 MeV to about 100 MeV using the spallation neutron source at WNR/LAMPF. Particle detection with energy measurement and particle identification is accomplished by two-element {Delta}E-E counters, three-element {Delta}E{sub l}-{Delta}E{sub 2}-E counters or with pulse-shape discrimination using scintillators directly in the neutron beam. The experimental techniques for these measurements are described and comparisons made among the different approaches. This presentation introduces five papers contributed to this conference.

  9. Drowning risks to epileptic children: a study from Hawaii.

    PubMed Central

    Pearn, J; Bart, R; Yamaoka, R

    1978-01-01

    The role of epileptiform seizures in causing drowning and near-drowning among children was studied by examining the case reports of all 140 childhood immersion accidents that occurred in an area of Hawaii over five years. Four of the 140 immersion accidents were caused partly by epileptiform seizures, but none were fatal. The combined results of the Hawaiian and Brisbane studies (total population studied over five years 1 600 000) showed that no epileptic children died from accidents in the sea or in swimming pools; and the 2.9% incidence of immersion accidents due to seizures in the Hawaiian study compares well with the incidence found in other series. If an epileptic child is mentally normal, well controlled with anticonvulsants, and supervised in the water then the risk of drowning is very small. PMID:709318

  10. Charge transfer through DNA/DNA duplexes and DNA/RNA hybrids: complex theoretical and experimental studies.

    PubMed

    Kratochvílová, Irena; Vala, Martin; Weiter, Martin; Špérová, Miroslava; Schneider, Bohdan; Páv, Ondřej; Šebera, Jakub; Rosenberg, Ivan; Sychrovský, Vladimír

    2013-01-01

    Oligonucleotides conduct electric charge via various mechanisms and their characterization and understanding is a very important and complicated task. In this work, experimental (temperature dependent steady state fluorescence spectroscopy, time-resolved fluorescence spectroscopy) and theoretical (Density Functional Theory) approaches were combined to study charge transfer processes in short DNA/DNA and RNA/DNA duplexes with virtually equivalent sequences. The experimental results were consistent with the theoretical model - the delocalized nature of HOMO orbitals and holes, base stacking, electronic coupling and conformational flexibility formed the conditions for more effective short distance charge transfer processes in RNA/DNA hybrids. RNA/DNA and DNA/DNA charge transfer properties were strongly connected with temperature affected structural changes of molecular systems - charge transfer could be used as a probe of even tiny changes of molecular structures and settings. PMID:23968861

  11. Two particle model for studying the effects of space-charge force on strong head-tail instabilities

    NASA Astrophysics Data System (ADS)

    Chin, Yong Ho; Chao, Alexander Wu; Blaskiewicz, Michael M.

    2016-01-01

    In this paper, we present a new two particle model for studying the strong head-tail instabilities in the presence of the space-charge force. It is a simple expansion of the well-known two particle model for strong head-tail instability and is still analytically solvable. No chromaticity effect is included. It leads to a formula for the growth rate as a function of the two dimensionless parameters: the space-charge tune shift parameter (normalized by the synchrotron tune) and the wakefield strength, ϒ . The three-dimensional contour plot of the growth rate as a function of those two dimensionless parameters reveals stopband structures. Many simulation results generally indicate that a strong head-tail instability can be damped by a weak space-charge force, but the beam becomes unstable again when the space-charge force is further increased. The new two particle model indicates a similar behavior. In weak space-charge regions, additional tune shifts by the space-charge force dissolve the mode coupling. As the space-charge force is increased, they conversely restore the mode coupling, but then a further increase of the space-charge force decouples the modes again. This mode coupling/decoupling behavior creates the stopband structures.

  12. The surface charge density effect on the electro-osmotic flow in a nanochannel: a molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Rezaei, M.; Azimian, A. R.; Semiromi, D. Toghraie

    2015-05-01

    The electro-osmotic flow of an aqueous solution of NaCl between two parallel silicon walls is studied through a molecular dynamics simulation. The objective here is to examine the dependency of the electro-osmotic flow on the surface charge density by considering the changes made in the structural properties of the electric double layer (EDL). The ion concentration, velocity profiles, and electric charge density of the electrolyte solution are investigated. Due to the partially charged atoms of the water molecules, water concentration is of a layered type near the wall. The obtained profiles revealed that an increase in the surface charge density, at low surface charges where the governing electrostatic coupling regime is Debye-Hückel, increases both the electro-osmotic velocity and the EDL thickness; whereas, a decreasing trend is observed in these two parameters in the intermediate regime. For high values of surface charge density, due to the charge inversion phenomenon, the reversed electro-osmotic flow will be generated in the channel. Results indicate that the absolute value of the reversed electro-osmotic velocity rises with an increase in the surface charge density.

  13. Further Studies on the Origins of Asymmetric Charge Partitioning in Protein Homodimers

    PubMed Central

    Jurchen, John C.; Garcia, David E.; Williams, Evan R.

    2005-01-01

    Dissociation of gas-phase protonated protein dimers into their constituent monomers can result in either symmetric or asymmetric charge partitioning. Dissociation of α-lactalbumin homodimers with 15+ charges results in a symmetric, but broad, distribution of protein monomers with charge states centered around 8+/7+. In contrast, dissociation of the 15+ heterodimer consisting of one molecule in the oxidized form and one in the reduced form results in highly asymmetric charge partitioning in which the reduced species carries away predominantly 11+ charges, and the oxidized molecule carries away 4+ charges. This result cannot be adequately explained by differential charging occurring either in solution or in the electrospray process, but appears to be best explained by the reduced species unfolding upon activation in the gas phase with subsequent separation and proton transfer to the unfolding species in the dissociation complex to minimize Coulomb repulsion. For dimers of cytochrome c formed directly from solution, the 17+ charge state undergoes symmetric charge partitioning whereas dissociation of the 13+ is asymmetric. Reduction of the charge state of dimers with 17+ charges to 13+ via gas-phase proton transfer and subsequent dissociation of the mass selected 13+ ions results in a symmetric charge partitioning. This result clearly shows that the structure of the dimer ions with 13+ charges depends on the method of ion formation and that the structural difference is responsible for the symmetric versus asymmetric charge partitioning observed. This indicates that the asymmetry observed when these ions are formed directly from solution must come about due either to differences in the monomer conformations in the dimer that exist in solution or that occur during the electrospray ionization process. These results provide additional evidence for the origin of charge asymmetry that occurs in the dissociation of multiply charged protein complexes and indicate that some

  14. 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. PMID:25410886

  15. Drug use in children: cohort study in three European countries

    PubMed Central

    Verhamme, Katia M C; Nicolosi, Alfredo; Murray, Macey L; Neubert, Antje; Caudri, Daan; Picelli, Gino; Sen, Elif Fatma; Giaquinto, Carlo; Cantarutti, Luigi; Baiardi, Paola; Felisi, Maria-Grazia; Ceci, Adriana; Wong, Ian C K

    2008-01-01

    Objective To provide an overview of drug use in children in three European countries. Design Retrospective cohort study, 2000-5. Setting Primary care research databases in the Netherlands (IPCI), United Kingdom (IMS-DA), and Italy (Pedianet). Participants 675 868 children aged up to 14 (Italy) or 18 (UK and Netherlands). Main outcome measure Prevalence of use per year calculated by drug class (anatomical and therapeutic). Prevalence of “recurrent/chronic” use (three or more prescriptions a year) and “non-recurrent” or “acute” use (less than three prescriptions a year) within each therapeutic class. Descriptions of the top five most commonly used drugs evaluated for off label status within each anatomical class. Results Three levels of drug use could be distinguished in the study population: high (>10/100 children per year), moderate (1-10/100 children per year), and low (<1/100 children per year). For all age categories, anti-infective, dermatological, and respiratory drugs were in the high use group, whereas cardiovascular and antineoplastic drugs were always in the low use group. Emollients, topical steroids, and asthma drugs had the highest prevalence of recurrent use, but relative use of low prevalence drugs was more often recurrent than acute. In the top five highest prevalence drugs topical inhaled and systemic steroids, oral contraceptives, and topical or systemic antifungal drugs were most commonly used off label. Conclusion This overview of outpatient paediatric prescription patterns in a large European population could provide information to prioritise paediatric therapeutic research needs. PMID:19029175

  16. 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.

  17. Oral habits in children--a prevalence study.

    PubMed

    Shetty, S R; Munshi, A K

    1998-06-01

    This epidemiological study was conducted upon 4,590 school children to find the prevalence of oral habits in Mangalore in relation to their age and sex and to find the correlation, if any, between the habits and the malocclusion status. We noted that 29.7% of the population had habits of which 3. 1% had digit sucking, 4.6% mouth breathing, 3.02% tongue thrusting, 6.2% bruxism, 6% lip/cheek biting, 12.7% nail biting, 9.8% pencil biting and 0. 09% masochistic habits respectively. Digit sucking, pencil biting and tongue thrust were highly prevalent among Group 1 (3-6 years) children. Mouth breathing and bruxism were significant in Group 2 (7-12 years) cases whereas lip/cheek biting and nail biting were more common in Group 3 (13-16 years) cases. Digit sucking, tongue thrust, mouth breathing and bruxism were more prevalent among the boys whereas lip/cheek biting, nail biting and pencil biting were more prevalent among the girls. 28.95% of the children in Group 2 and 3 with habits had malocclusion. There was a significant correlation between class I type 2, class II div 1 and tongue thrust and mouth breathing whereas children with digit sucking showed a high correlation with class I type 2 malocclusion. PMID:11813757

  18. A Preliminary Neuroimaging Study of Preschool Children with ADHD

    PubMed Central

    E.M., Mahone; D., Crocetti; M.E., Ranta; A., Gaddis; M., Cataldo; K.J., Slifer; M.B., Denckla; S.H., Mostofsky

    2012-01-01

    Attention-deficit/Hyperactivity Disorder (ADHD) is a developmental disorder which, by current definition, has onset prior to age 7 years. MRI studies have provided some insight into brain differences associated with ADHD, but thus far have almost exclusively focused on children ages 7 years and older. To better understand the neurobiological development of ADHD, cortical and subcortical brain development should be systematically examined in younger children presenting with symptoms of the disorder. High resolution anatomical (MPRAGE) images, acquired on a 3.0T scanner, were analyzed in a total of 26 preschoolers, ages 4–5 years (13 with ADHD, 13 controls, matched on age and sex). The ADHD sample was diagnosed using DSM-IV criteria, and screened for language disorders. Cortical regions were delineated and measured using automated methods in Freesurfer; basal ganglia structures were manually delineated. Children with ADHD showed significantly reduced caudate volumes bilaterally; in contrast, there were no significant group differences in cortical volume or thickness in this age range. After controlling for age and total cerebral volume, left caudate volume was a significant predictor of hyperactive/impulsive, but not inattentive symptom severity. Anomalous basal ganglia, particularly caudate, development appears to play an important role among children presenting with early onset symptoms of ADHD. PMID:21660881

  19. The National Children's Study: an opportunity for medical toxicology.

    PubMed

    Mortensen, Mary Ellen; Hirschfeld, Steven

    2012-06-01

    The National Children's Study (NCS) is a national longitudinal study that will prospectively investigate the influence of biological, environmental, genetic, and social factors on the health and development of US children. The NCS was mandated by the Children's Health Act of 2000 (Public Law 106-310) and is being implemented by the National Institutes of Health with input from the Centers for Disease Control and Prevention (CDC), the Environmental Protection Agency, and other federal departments and agencies. The NCS is a data-driven, evidence-based, community- and participant-informed study. Given its scale and scope, the NCS is an integrated system using several data acquisition strategies intended to provide evidenced-based design of methodologies and protocols. These strategies include the Vanguard Study, the Main Study, and formative research and sub-studies. The Vanguard Study, a pilot study, is currently underway and has been expanded from 7 to 37 study locations. The original study protocols and recruitment strategy have been field tested and revisions are under consideration. The CDC is collaborating with NCS in a pilot study that evaluates biological specimen protocols and will provide results on a broad array of environmental chemical exposures and nutritional indicators for a sample of Vanguard Study participants. This study is an example of the kind of collaborative opportunity that would benefit the NCS. Medical toxicologists have unique training in basic and clinical toxicology and laboratory assessments, and by partnering with study centers, both the NCS design and future NCS research projects could be enhanced. PMID:22108840

  20. Assessment of mastication in healthy children and children with cerebral palsy: a validity and consistency study.

    PubMed

    Remijn, L; Speyer, R; Groen, B E; Holtus, P C M; van Limbeek, J; Nijhuis-van der Sanden, M W G

    2013-05-01

    The aim of this study was to develop the Mastication Observation and Evaluation instrument for observing and assessing the chewing ability of children eating solid and lumpy foods. This study describes the process of item definition and item selection and reports the content validity, reproducibility and consistency of the instrument. In the developmental phase, 15 experienced speech therapists assessed item relevance and descriptions over three Delphi rounds. Potential items were selected based on the results from a literature review. At the initial Delphi round, 17 potential items were included. After three Delphi rounds, 14 items that regarded as providing distinctive value in assessment of mastication (consensus >75%) were included in the Mastication Observation and Evaluation instrument. To test item reproducibility and consistency, two experts and five students evaluated video recordings of 20 children (10 children with cerebral palsy aged 29-65 months and 10 healthy children aged 11-42 months) eating bread and a biscuit. Reproducibility was estimated by means of the intraclass correlation coefficient (ICC). With the exception of one item concerning chewing duration, all items showed good to excellent intra-observer agreement (ICC students: 0.73-1.0). With the exception of chewing duration and number of swallows, inter-observer agreement was fair to excellent for all items (ICC experts: 0.68-1.0 and ICC students: 0.42-1.0). Results indicate that this tool is a feasible instrument and could be used in clinical practice after further research is completed on the reliability of the tool. PMID:23445464

  1. 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.

  2. Spectrophotometric and electrical studies of charge-transfer complexes of sodium flucloxacillin with pi-acceptors.

    PubMed

    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 pi-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 microg 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, (1)H 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. PMID:16527531

  3. ANALYSIS OF NHEXAS DATA FROM THE CHILDREN'S PESTICIDE EXPOSURE STUDY IN MINNESOTA

    EPA Science Inventory

    The "Minnesota Children's Pesticide Exposure Study" (MNCPES) evaluated the feasibility of conducting a multipathway exposure monitoring study with a sample of children, and implemented a strategy for collection and integration of survey information (e.g., pesticide usage and act...

  4. Charge Carrier Dynamics in Transition Metal Oxides Studied by Femtosecond Transient Extreme Ultraviolet Absorption Spectroscopy

    NASA Astrophysics Data System (ADS)

    Jiang, Chang-Ming

    With the ability to disentangle electronic transitions that occur on different elements and local electronic structures, time-resolved extreme ultraviolet (XUV) spectroscopy has emerged as a powerful tool for studying ultrafast dynamics in condensed phase systems. In this dissertation, a visible-pump/XUV-probe transient absorption apparatus with femtosecond resolution was constructed to investigate the carrier relaxation dynamics in semiconductors after photo-excitation. This includes timescales for carrier thermalization by carrier-carrier and carrier-phonon scattering. The 30 -- 72 eV photon energy coverage (17 -- 40 nm wavelength) generated by a table-top XUV light source is suitable for probing the 3p-to-3d core level absorptions of various transition metal oxides (TMOs) with specificities to elements and oxidation states. In Chapter 1, a brief introduction to charge carrier dynamics in semiconductor-based materials is given. In addition, fundamentals of core-level spectroscopy and the high harmonic generation (HHG) process are also addressed in this introductory chapter. Specifications of the experimental apparatus that was constructed are summarized in Chapter 2, including the design concepts and characterization of performance. Chapter 3 presents the spectral tunability of the XUV pulses generated from a semi-infinite gas cell (SIGC), as well as the data acquisition procedures. Charge carrier relaxation dynamics in Co3O4 following the charge transfer excitation pathway at 400 nm are documented in Chapter 4. In Chapter 5, various visible pump wavelengths are used to excite Co3O4 and the differences in the carrier dynamics versus excitation wavelength are considered. After selectively photoexciting a Si/TiO2 heterojunction, the resulted electron transfer process is observed and reported in Chapter 6. The concluding remarks of the dissertation are made in Chapter 7, while several ongoing time-resolved experiments are addressed in the Appendix sections.

  5. 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.

  6. 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.

  7. New Missions and the Future of Solar Wind Charge Exchange Studies

    NASA Astrophysics Data System (ADS)

    Kuntz, K. D.

    2016-04-01

    Several newly approved missions in astrophysics and heliophysics will study solar wind charge-exchange (SWCX) directly as either primary or secondary science goals. Of these, SMILE and CuPID will study the magnetosheath by means of the SWCX emission and will provide a direct measure of the magnetospheric emission from in both the 1/4 keV and 3/4 keV bands. HaloSAT observations will be designed to minimize the magnetospheric component for its observations of the Galactic Halo, but will make at least some dedicated observations of heliospheric SWCX. I will outline the simulation needs and observational strategies required to study SWCX for astrophysical purposes.

  8. The study of capacitive deionization behavior of a carbon nanotube electrode from the perspective of charge efficiency.

    PubMed

    Li, Haibo; Liang, Sen; Gao, Mangmang; Li, Guolong; Li, Jin; He, Lijun

    2015-01-01

    In this work, the capacitive deionization (CDI) performance of a single-walled carbon nanotube (CNT) electrode has been studied from the point view of charge efficiency theory. It is revealed here that the charge efficiency of a CNT electrode is strongly dependent upon the cell voltage and solution concentration. Either the high cell voltage or the low ionic strength results in a high charge efficiency, implying that CDI is expected to be a promising technique for an aqueous solution with low ionic strength. Additionally, it is found that the high decay constant and high electrical double-layer capacity are beneficial to enhance electrosorption performance. PMID:25607673

  9. 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.

  10. [Criteria for determining the adaptation of children to studying loads].

    PubMed

    Potupchik, T V; Makarova, M V; Prakhin, E I; Evert, L S; Baksheeva, S S

    2011-01-01

    Three hundred and two Krasnoyarsk gymnasium students were examined to define criteria for determining the adaptation to high schooling loads. The values of the emotional status and adaptive processes were studied in children with varying resistance and varying mastering capacities; the impact of cardiovascular parameters on their adaptive process was defined The criteria for estimating the adaptation to high schooling loads were the presence or absence of acute chills and neurotic reactions, cardiovascular performance, and psychoemotional status. PMID:22250390

  11. Hearing the voices of children: self-reported information on children's experiences during research procedures: a study protocol

    PubMed Central

    Staphorst, Mira S; Hunfeld, Joke A M; Timman, Reinier; Passchier, Jan; van Goudoever, Johannes B

    2015-01-01

    Introduction In paediatric research, there is a tension between what you can ask from a child and what is needed for the development of evidence-based treatments. To find an optimal balance in conducting clinical research and protecting the child, it is necessary to have empirical data on children's experiences. Until now, there are scarce empirical data on the experiences from the perspective of the child. In this manuscript, we describe the protocol of a two-phase study measuring children's self-reported experiences during research procedures. Methods and analysis In the first phase of our study, we aim to interview approximately 40 children (6–18 years) about their self-reported experiences during research procedures. In the second phase, we will develop a questionnaire to measure children's experiences during research procedures in a quantitative way. We will use the interview outcomes for the development of this questionnaire. Next, we will measure the experiences of children during seven research procedures with this questionnaire. A one-month follow-up is conducted to investigate the emotional impact of the research procedures on the children. Children will be recruited from different research studies in three academic children's hospitals in the Netherlands. Ethics and dissemination The ethics committee of the VU University medical center evaluated both studies and indicated that there was no risk/discomfort associated, stating that both phases are exempt from getting approval under the Dutch Law. Dissemination of results will occur by conference presentations and peer-reviewed publications. The findings of our project can help Institutional Review Boards and paediatric researchers when evaluating the discomforts of research procedures described in study protocols or when designing a study. Information on experiences of children involved in previous studies may also help children and parents in future research with their decision-making about

  12. 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).

  13. Children's Sexual Thinking: A Comparative Study of Children Aged 5 to 15 Years in Australia, North America, Britain and Sweden.

    ERIC Educational Resources Information Center

    Goldman, Ronald; Goldman, Juliette

    The purpose of this cross-national descriptive study is to measure the extent of children's sexual knowledge and sexual understanding at various ages and to identify what processes of thought children use in trying to explain biological functions and the phenomena of their own bodies as they grow and change. Sexual thinking is defined as thinking…

  14. 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 strategies…

  15. 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…

  16. 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…

  17. 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…

  18. 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.

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

    DOE PAGESBeta

    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

  20. 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. PMID:27189936

  1. 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.

  2. 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.

  3. 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.

  4. 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).

  5. Charge transport studies of polymeric photovoltaic thin films with an electron blocking and trapping layer

    NASA Astrophysics Data System (ADS)

    Lee, Harrison K. H.; Chan, Kevin K. H.; So, S. K.

    2012-06-01

    The transport properties of two photovoltaic polymers, poly(3-hexylthiophene) (P3HT) and poly(2,7-carbazole) derivative (PCDTBT), and their polymer:fullerene bulk heterojunction (BHJ) are studied by space-charge-limited current (SCLC), dark-injection space-charge-limited current (DI-SCLC), and admittance spectroscopy(AS). For a nominally hole-only device, electrons leakage occurs. This results in a current larger than the theoretical SCLC and ill-defined DI-SCLC and AS signals. In order to prevent electron leakage, a hole-transporting but electron blocking/trapping thin layer is added between active layer and Au. The layer composed of copper phthalocyanine (CuPc) doped into an amine-based small molecule. Using this interlayer, well-defined carrier transit time can be obtained for mobility extraction. With a suitable interlayer to suppress undesirable carrier injection and transport, these techniques should find broad applications in the transport characterization of narrow gap photovoltaic polymers and BHJ blends.

  6. The Childrens Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) Study

    EPA Science Inventory

    The Children's Total Exposure to Persistent Pesticides and Other Persistent Pollutant (CTEPP) study was one of the largest aggregate exposure studies of young children in the United States. The CTEPP study examined the exposures of about 260 preschool children and their primary a...

  7. The Childrens Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) Study -- Ohio

    EPA Science Inventory

    The Children's Total Exposure to Persistent Pesticides and Other Persistent Pollutant (CTEPP) study was one of the largest aggregate exposure studies of young children in the United States. The CTEPP study examined the exposures of about 260 preschool children and their primary a...

  8. THE CHILDRENS TOTAL EXPOSURE TO PERSISTENT PESTICIDES AND OTHER PERSISTENT ORGANIC POLLUTANTS (CTEPP) STUDY -- NORTH CAROLINA

    EPA Science Inventory

    The Children's Total Exposure to Persistent Pesticides and Other Persistent Pollutant (CTEPP) study was one of the largest aggregate exposure studies of young children in the United States. The CTEPP study examined the exposures of about 260 preschool children and their primary a...

  9. 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…

  10. A Naturalistic Study of Memory for Object Location in Very Young Children.

    ERIC Educational Resources Information Center

    DeLoache, Judy S.

    Two naturalistic studies of young (18-30 month old) children's memory for object location are reported which indicate that young children's memories are better than non-naturalistic studies suggest and that they have confidence in their memories. In the first study, 17 children were observed attempting to find objects they had watched their…

  11. Charge collection studies on custom silicon detectors irradiated up to 1.6·1017 neq/cm-2

    NASA Astrophysics Data System (ADS)

    Kramberger, G.; Cindro, V.; Mandić, I.; Mikuž, M.; Zavrtanik, M.

    2013-08-01

    Silicon n+-p diodes with special design of the implant — so called ``spaghetti diodes'' — were used to study the impact of implantation process on charge multiplication after irradiations to extremely large 1 MeV neutron equivalent fluences of reactor neutrons up to 1.6·1017 cm-2. Silicon remains functional even at these unprecedented levels of irradiation. Above 1015 cm-2 collected charge (Q) grows linearly with bias voltage, with the Q-V slope exhibiting a power law dependence on fluence. Different implantation processes were implemented on samples to study the impact of implantation on charge multiplication. ``Spaghetti'' diodes of different thicknesses were also compared to conventional strip and pad detectors in order to determine the impact of different electric and weighting field on the collected charge.

  12. Molecular structure and charge transfer contributions to nonlinear optical property of 2-Methyl-4-nitroaniline: A DFT study

    NASA Astrophysics Data System (ADS)

    Jasmine, G. Femina; Amalanathan, M.; Roy, S. Dawn Dharma

    2016-05-01

    The Charge transfer contributions to the second-order nonlinear optical properties of 2-Methyl-4-nitroaniline have been performed by means of DFT computation. The vibrational contribution studies of 2-Methyl-4-nitroaniline have also been performed using FTIR, FT-Raman analysis. More support on the experimental findings were added from the quantum chemical studies performed with DFT (B3LYP) method using 6-311++G(d,p)basis sets. Natural bond orbital analysis confirms the presence of intramolecular charge transfer and the hydrogen bonding interaction. The HOMO and LUMO analysis reveals the possibility of charge transfer within the molecule. The first order hyperpolarizability (α0) and related properties (β,α0 and Δα) of 2-Methyl-4-nitroaniline were calculated. In addition, molecular electrostatic potential (MEP), charge analysis also were investigated using theoretical calculations.

  13. Coordinated changes of adenylate energy charge and ATP/ADP: use in ecotoxicological studies.

    PubMed

    Thébault, M T; Raffin, J P; Picado, A M; Mendonça, E; Skorkowski, E F; Le Gal, Y

    2000-05-01

    The coordinated variations of the adenylate energy charge and ATP/ADP ratio were modeled and a function that depends on the numerical value of the adenylate kinase-catalyzed reaction has been derived. The model allows sensitive detection of the effects of xenobiotics on adenylate kinase and its cellular environment and offers a robust estimation of the direct or indirect effects of pollutants on the adenylate kinase system: data obtained in laboratory studies on shrimp exposed to cadmium and in field studies on oysters either exposed to polychloro-biphenyl compounds or located in a heavily polluted area indicate that xenobiotics affect the adenylate kinase reaction directly or by changing its cellular environment. These results demonstrate that application of the model to the treatment of ecotoxicological data allows detection of energetic changes that would have been missed by simple analysis of the usual energetic parameters, and should overcome problems encountered in using energetic parameters during assessment of pollution monitoring. PMID:10805989

  14. Beam dynamics study of RFQ for CADS with a 3D space-charge-effect

    NASA Astrophysics Data System (ADS)

    Li, Chao; Zhang, Zhi-Lei; Qi, Xin; Xu, Xian-Bo; He, Yuan; Yang, Lei

    2014-03-01

    The ADS (accelerator driven subcritical system) project was proposed by the Chinese Academy of Sciences. The initial proton beams delivered from an electron cyclotron resonance ion source can be effectively accelerated by 162.5 MHz 4.2 m long room temperature radio-frequency-quadrupoles (RFQ) operating in CW mode. To test the feasibility of this physical design, a new Fortran code for RFQ beam dynamics study, which is space charge dominated, was developed. This program is based on Particle-In-Cell (PIC) technique in the time domain. Using the RFQ structure designed for the CADS project, the beam dynamics behavior is performed. The well-known simulation code TRACK is used for benchmarks. The results given by these two codes show good agreements. Numerical techniques as well as the results of beam dynamics studies are presented in this paper.

  15. Studies of Charged Particle Emission in the Decay of 45Fe

    SciTech Connect

    Miernik, K.; Dominik, W.; Janas, Z.; Pfutzner, M.; Grigorenko, L.; Bingham, C. R.; Czyrkowski, H.; Cwiok, Mikolaj; Darby, Iain; Dabrowski, Ryszard; Ginter, T. N.; Grzywacz, Robert; Karny, M.; Korgul, A.; Kusmierz, W.; Liddick, Sean; Rajabali, Mustafa; Rykaczewski, Krzysztof Piotr; Stolz, A.

    2008-01-01

    The decay of extremely neutron-deficient isotope 45Fe has been studied by using a new type of gaseous detector in which a technique of optical imaging is used to record tracks of charged particles. The two-proton radioactivity and the beta-decay channels accompanied by proton(s) emission were clearly identified. For the first time, the angular and energy correlations between two protons emitted from the 45Fe ground-state were measured. The obtained distributions were confronted with predictions of a three-body model. Studies of beta-decay channels of 45Fe provided first unambiguous evidence for the beta-delayed three proton emission.

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

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

    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.

  17. Simulation study of the dynamic performance of a MRC plant with refrigerant charged or leaked

    NASA Astrophysics Data System (ADS)

    Sun, Heng; Shu, Dan; Jiang, Zhihua

    2012-01-01

    The running condition of a MRC plant is affected by the charge or leakage of the refrigerant. It is significant for the design and operation of the plant. A new model which is established based on the process simulation, mass conservation and characteristics of the system was employed to study the dynamic performance in these cases. The results show that the light composition mainly affects the pressure and the heavy composition affects the liquid level of vessel more obviously. This is due to the fact that the light composition mainly stays in the vapor phase and the heavies stay in the liquid phase mostly. The case when leakages occur at different location was also studied. The results can provide useful information for the adjustment of mixture refrigerant and operation of a MRC plant.

  18. 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.

  19. 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. PMID:26874484

  20. 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.

  1. 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...

  2. 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.

  3. Invasiveness of pharmacokinetic studies in children: a systematic review

    PubMed Central

    Altamimi, Mohammed I; Choonara, Imti; Sammons, Helen

    2016-01-01

    Objectives To explore whether pharmacokinetic (PK) studies in paediatric patients are becoming less invasive. This will be evaluated by analysing the number of samples and volume of blood collected for each study within four different decades. Methods A systematic literature review was performed to identify PK papers describing number of samples and volume of blood collected in studies of children aged 0–18 years. The following databases were searched: MEDLINE (1946 to December 2015), EMBASE (1974 to December 2015), International Pharmaceutical Abstracts (1970 to December 2015), CINAHL and Cochrane Library. Results A total of 549 studies were identified between 1974 and 2015. There were 52 studies between 1976 and 1985, 105 between 1986 and 1995, 201 between 1996 and 2005 and 191 between 2006 and 2015. The number of blood samples collected per participant increased between the first two decades (p=0.013), but there was a decrease in the number of samples in the subsequent two decades (p=0.044 and p<0.001, respectively). Comparing the first and last decades, there has been no change in the number of blood samples collected. There were no significant differences in volume collected per sample or total volume per child in any of the age groups. There was however a significant difference in the frequency of blood sampling between population PK studies (median 5 (IQR 3–7)) and non-population PK studies (median 8 (IQR 6–10); p=<0.001). Conclusions The number of blood samples collected for PK studies in children rose in 1985–1995 and subsequently declined. There was no overall change in the volume of blood collected over the 4 decades. The usage of population PK methods reduces the frequency of blood sampling in children. PMID:27431899

  4. 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. PMID:12026266

  5. A longitudinal study of children exposed to sulfur oxides.

    PubMed

    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 (SO2) and moderately different concentrations of particulate sulfate (SO4=). 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 SO2 levels (peak three-hour average concentration exceeded 2,500 micrograms/m3) and moderate particulate SO4= 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 SO2 concentration, in the presence of moderate particulate SO4= concentration, produced evidence of bronchial irritation in the subjects, but no chronic effect on lung function or lung function growth was detected. PMID:4014164

  6. 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.

  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. PMID:27017449

  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. Molecular dynamics study of charged dendrimers in salt-free solution: Effect of counterions

    NASA Astrophysics Data System (ADS)

    Gurtovenko, Andrey A.; Lyulin, Sergey V.; Karttunen, Mikko; Vattulainen, Ilpo

    2006-03-01

    Polyamidoamine dendrimers, being protonated under physiological conditions, represent a promising class of nonviral, nanosized vectors for drug and gene delivery. We performed extensive molecular dynamics simulations of a generic model dendrimer in a salt-free solution with dendrimer's terminal beads positively charged. Solvent molecules as well as counterions were explicitly included as interacting beads. We find that the size of the charged dendrimer depends nonmonotonically on the strength of electrostatic interactions demonstrating a maximum when the Bjerrum length equals the diameter of a bead. Many other structural and dynamic characteristics of charged dendrimers are also found to follow this pattern. We address such a behavior to the interplay between repulsive interactions of the charged terminal beads and their attractive interactions with oppositely charged counterions. The former favors swelling at small Bjerrum lengths and the latter promotes counterion condensation. Thus, counterions can have a dramatic effect on the structure and dynamics of charged dendrimers and, under certain conditions, cannot be treated implicitly.

  11. 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…

  12. The Development of Normal and Autistic Children: A Comparative Study.

    ERIC Educational Resources Information Center

    Wenar, Charles; And Others

    1986-01-01

    Evaluation of 195 normal children (aged 1-5 years), 160 normal children (aged 3-24 months), and 41 autistic children (aged 5-11 years) on the eight psychological variables of the Behavioral Rating Instrument for Autistic and Other Atypical Children indicated certain autistic behaviors are not normal at any stage of development. (Author/CB)

  13. Comprehensive study on charge trapping property of Si-containing hafnium-oxide polymorph

    NASA Astrophysics Data System (ADS)

    Inoue, Masao; Mizutani, Masaharu; Kadoshima, Masaru; Sonoda, Kenichiro; Yamashita, Tomohiro; Matsuura, Masazumi

    2016-08-01

    The electron-trapping property of Hf oxides with a wide range of Si contents (0–64 at. %) is studied as a charge storage layer of a nonvolatile memory. The largest flatband voltage shift in the MOS capacitor is obtained at a Si content of ∼20 at. %, which corresponds to the formation of a metastable crystalline phase such as a tetragonal or orthorhombic phase. First-principles calculation reveals that metastable phases tend to have a formation energy of oxygen vacancy lower than that of stable monoclinic ones. A schematic picture of traps in crystalline Hf oxides is provided. The metastable phase is also demonstrated to have retention characteristics superior to other phases.

  14. 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.

  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. Synthesis, characterization and biological studies of a charge transfer complex: 2-aminopyridinium-4-methylbenzenesulfonate.

    PubMed

    Vadivelan, Ganesan; Saravanabhavan, Munusamy; Murugesan, Venkatesan; Sekar, Marimuthu

    2015-06-15

    A single crystal charge transfer (CT) complex, 2-aminopyridinium-4-methylbenzenesulfonate (APTS) was synthesized and recrystallized by slow solvent evaporation solution growth method at room temperature. The complex has been characterized with the elemental analysis, UV-visible, infrared (IR), (1)H and (13)C nuclear magnetic resonance (NMR) spectra. Thermogravimetric (TG) and differential thermal analysis (DTA) were reported the thermal behaviour of the complex. Single crystal XRD studies showed that the orthorhombic nature of the crystal with space group Pbca. The biological activities of CT complex, such as DNA binding and antioxidant activity has been carried out. The results indicated that the compound could interact with DNA through intercalation and show significant capacity of scavenging with 2,2-diphenyl-2-picryl-hydrazyl (DPPH). PMID:25796016

  17. A detection system for charged-particle decay studies with a continuous-implantation method

    NASA Astrophysics Data System (ADS)

    Sun, L. J.; Xu, X. X.; Lin, C. J.; Wang, J. S.; Fang, D. Q.; Li, Z. H.; Wang, Y. T.; Li, J.; Yang, L.; Ma, N. R.; Wang, K.; Zang, H. L.; Wang, H. W.; Li, C.; Shi, C. Z.; Nie, M. W.; Li, X. F.; Li, H.; Ma, J. B.; Ma, P.; Jin, S. L.; Huang, M. R.; Bai, Z.; Wang, J. G.; Yang, F.; Jia, H. M.; Zhang, H. Q.; Liu, Z. H.; Bao, P. F.; Wang, D. X.; Yang, Y. Y.; Zhou, Y. J.; Ma, W. H.; Chen, J.

    2015-12-01

    A new detection system with high detection efficiency and low detection threshold has been developed for charged-particle decay studies, including β-delayed proton, α decay or direct proton emission from proton-rich nuclei. The performance was evaluated by using the β-delayed proton emitter 24Si produced by projectile fragmentation at the First Radioactive Ion Beam Line in Lanzhou. Under a continuous-beam mode, the isotopes of interest were implanted into two double-sided silicon strip detectors, where the subsequent decays were measured and correlated to the preceding implantations by using position and time information. The system allows us to measure protons with energies down to about 200 keV without obvious β background in the proton spectrum. Further application of the detection system can be extended to the measurements of β-delayed proton decay and the direct proton emission of more exotic proton-rich nuclei.

  18. 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.; University of Chinese Academy of Sciences, Beijing 100049 ; 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.

  19. Synthesis, characterization and biological studies of a charge transfer complex: 2-Aminopyridinium-4-methylbenzenesulfonate

    NASA Astrophysics Data System (ADS)

    Vadivelan, Ganesan; Saravanabhavan, Munusamy; Murugesan, Venkatesan; Sekar, Marimuthu

    2015-06-01

    A single crystal charge transfer (CT) complex, 2-aminopyridinium-4-methylbenzenesulfonate (APTS) was synthesized and recrystallized by slow solvent evaporation solution growth method at room temperature. The complex has been characterized with the elemental analysis, UV-visible, infrared (IR), 1H and 13C nuclear magnetic resonance (NMR) spectra. Thermogravimetric (TG) and differential thermal analysis (DTA) were reported the thermal behaviour of the complex. Single crystal XRD studies showed that the orthorhombic nature of the crystal with space group Pbca. The biological activities of CT complex, such as DNA binding and antioxidant activity has been carried out. The results indicated that the compound could interact with DNA through intercalation and show significant capacity of scavenging with 2,2-diphenyl-2-picryl-hydrazyl (DPPH).

  20. 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

  1. Laboratory-Based Studies of Eating among Children and Adolescents.

    PubMed

    Tanofsky-Kraff, Marian; Haynos, Ann F; Kotler, Lisa A; Yanovski, Susan Z; Yanovski, Jack A

    2007-01-01

    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

  2. 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. ...

  3. 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)

  4. Mapping the Journey from Home to School: A Study on Children's Representation of Space

    ERIC Educational Resources Information Center

    Thommen, Evelyne; Avelar, Silvania; Sapin, Veronique Zbinden; Perrenoud, Silvia; Malatesta, Dominique

    2010-01-01

    This paper describes a study conducted with 235 children from Brazil and Switzerland. The children, from 5 to 13 years of age, were asked to draw the journey they undertake every day from home to school. The purpose of the study is to understand the relationship between the cognitive development and map-drawing abilities of children in both…

  5. Motor Milestone Development in Young Children with Autism Spectrum Disorders: An Exploratory Study

    ERIC Educational Resources Information Center

    Liu, Ting

    2012-01-01

    This study aimed to determine if a sample of children currently diagnosed with autism spectrum disorders (ASDs) would have shown motor milestone delays before age three as compared to typically developing children. Given delays in motor skills, the study also strived to determine which specific skills might be delayed. Parents of 44 children who…

  6. 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…

  7. The Impact of Televised Aggression on Children: A Developmental Field Study.

    ERIC Educational Resources Information Center

    Cooper, Joel; Axsom, Danny

    Much of the television American children watch is violent in content. The evidence indicating that this programing increases children's aggressive behavior is not clear-cut, and some studies have shown a decrease in children's aggressive behavior. A study was conducted to test a more developmental perspective on the effects of violent television:…

  8. Characteristics and Dental Experiences of Autistic Children in Saudi Arabia: Cross-Sectional Study

    ERIC Educational Resources Information Center

    Murshid, Ebtissam Z.

    2011-01-01

    The purpose of this study is to report base line information about characteristics, and dental experiences of a group of autistic children in three major cities of Saudi Arabia. Most of the children (76.2%) included in the study were diagnosed with autism before the age of 5 years. More than half of the children (53.7%) had no previous dental…

  9. Family and Friend Relationships of Only Children: A Study of Adult Population in China.

    ERIC Educational Resources Information Center

    Huang, Gary

    If personal networks of only children differ from those of children with siblings, then study of the different patterns of personal association is especially relevant to the understanding of social change in China, where the population of children without siblings is rapidly increasing. A study of these differential social networks used data…

  10. 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…

  11. The Case of the Missing Childhoods: Methodological Notes for Composing Children in Writing Studies

    ERIC Educational Resources Information Center

    Dyson, Anne Haas

    2013-01-01

    Writing studies has been an intellectual playground dominated by the "big kids." If we are to understand how writing becomes "relevant" to children as children, then we must study them, not for who they are becoming, but for who they are in life spaces shared with other children. This essay on the methodology entailed in…

  12. 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...

  13. 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

  14. 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

  15. Disclosure of parental HIV infection to children and psychosocial impact on children in China: a qualitative study

    PubMed Central

    Zhang, Liying; Li, Xiaoming; Zhao, Junfeng; Zhao, Guoxiang; Kaljee, Linda; Stanton, Bonita

    2014-01-01

    This qualitative study aims to investigate parental HIV disclosure and psychological impact from the perspectives of their children. In-depth individual interviews with 47 children who had lost one or both parents to AIDS were conducted in China. All transcripts were coded using the software ATLAS.ti 5. Results showed that few of children knew of parental HIV status before the death of their parents. The main disclosers were the children’s current caregivers. Some children knew about their parent’s HIV infection based on their own observations or through overheard conversation, or their interactions with villagers. Both positive and negative psychological outcomes related to parental HIV disclosure were reported. Psychological counseling is needed for both parents and children to dealing with the parental HIV infection. PMID:24761258

  16. 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

  17. Approaches to Children's Exposure Assessment: Case Study with Diethylhexylphthalate (DEHP).

    PubMed

    Ginsberg, Gary; Ginsberg, Justine; Foos, Brenda

    2016-01-01

    Children's exposure assessment is a key input into epidemiology studies, risk assessment and source apportionment. The goals of this article are to describe a methodology for children's exposure assessment that can be used for these purposes and to apply the methodology to source apportionment for the case study chemical, diethylhexylphthalate (DEHP). A key feature is the comparison of total (aggregate) exposure calculated via a pathways approach to that derived from a biomonitoring approach. The 4-step methodology and its results for DEHP are: (1) Prioritization of life stages and exposure pathways, with pregnancy, breast-fed infants, and toddlers the focus of the case study and pathways selected that are relevant to these groups; (2) Estimation of pathway-specific exposures by life stage wherein diet was found to be the largest contributor for pregnant women, breast milk and mouthing behavior for the nursing infant and diet, house dust, and mouthing for toddlers; (3) Comparison of aggregate exposure by pathways vs biomonitoring-based approaches wherein good concordance was found for toddlers and pregnant women providing confidence in the exposure assessment; (4) Source apportionment in which DEHP presence in foods, children's products, consumer products and the built environment are discussed with respect to early life mouthing, house dust and dietary exposure. A potential fifth step of the method involves the calculation of exposure doses for risk assessment which is described but outside the scope for the current case study. In summary, the methodology has been used to synthesize the available information to identify key sources of early life exposure to DEHP. PMID:27376320

  18. 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.

  19. 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...

  20. Developmental Characteristics of Urban Children: Contrasts Between Children Cared for in their Own Homes, in Homes of Grandparents and in Agency Foster Care. A Pilot Study. Final Report to the Office of Child Development - Agency for Children, Youth and Families.

    ERIC Educational Resources Information Center

    Stanley, Jay; And Others

    This descriptive study of the developmental characteristics of urban children, most of whom were black, was a pilot study designed to take a broad overview of agency foster children as compared with children who had been cared for by a grandparent (usually the grandmother) and children cared for by their parents. In this comparison, the agency…

  1. A systematic study of neutral and charged 3d-metal trioxides and tetraoxides

    NASA Astrophysics Data System (ADS)

    Pradhan, Kalpataru; Gutsev, Gennady L.; Weatherford, Charles A.; Jena, Purusottam

    2011-04-01

    Using density functional theory with generalized gradient approximation, we have performed a systematic study of the structure and properties of neutral and charged trioxides (MO3) and tetraoxides (MO4) of the 3d-metal atoms. The results of our calculations revealed a number of interesting features when moving along the 3d-metal series. (1) Geometrical configurations of the lowest total energy states of neutral and charged trioxides and tetraoxides are composed of oxo and/or peroxo groups, except for CuO3- and ZnO3- which possess a superoxo group, CuO4+ and ZnO4+ which possess two superoxo groups, and CuO3+, ZnO3+, and ZnO4- which possess an ozonide group. While peroxo groups are found in the early and late transition metals, all oxygen atoms bind chemically to the metal atom in the middle of the series. (2) Attachment or detachment of an electron to/from an oxide often leads to a change in the geometry. In some cases, two dissociatively attached oxygen atoms combine and form a peroxo group or a peroxo group transforms into a superoxo group and vice versa. (3) The adiabatic electron affinity of as many as two trioxides (VO3 and CoO3) and four tetraoxides (TiO4, CrO4, MnO4, and FeO4) are larger than the electron affinity of halogen atoms. All these oxides are hence superhalogens although only VO3 and MnO4 satisfy the general superhalogen formula.

  2. A systematic study of neutral and charged 3d-metal trioxides and tetraoxides.

    PubMed

    Pradhan, Kalpataru; Gutsev, Gennady L; Weatherford, Charles A; Jena, Purusottam

    2011-04-14

    Using density functional theory with generalized gradient approximation, we have performed a systematic study of the structure and properties of neutral and charged trioxides (MO(3)) and tetraoxides (MO(4)) of the 3d-metal atoms. The results of our calculations revealed a number of interesting features when moving along the 3d-metal series. (1) Geometrical configurations of the lowest total energy states of neutral and charged trioxides and tetraoxides are composed of oxo and∕or peroxo groups, except for CuO(3)(-) and ZnO(3)(-) which possess a superoxo group, CuO(4)(+) and ZnO(4)(+) which possess two superoxo groups, and CuO(3)(+), ZnO(3)(+), and ZnO(4)(-) which possess an ozonide group. While peroxo groups are found in the early and late transition metals, all oxygen atoms bind chemically to the metal atom in the middle of the series. (2) Attachment or detachment of an electron to∕from an oxide often leads to a change in the geometry. In some cases, two dissociatively attached oxygen atoms combine and form a peroxo group or a peroxo group transforms into a superoxo group and vice versa. (3) The adiabatic electron affinity of as many as two trioxides (VO(3) and CoO(3)) and four tetraoxides (TiO(4), CrO(4), MnO(4), and FeO(4)) are larger than the electron affinity of halogen atoms. All these oxides are hence superhalogens although only VO(3) and MnO(4) satisfy the general superhalogen formula. PMID:21495753

  3. Dissociation of hydrophobic and charged nano particles in aqueous guanidinium chloride and urea solutions: A molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Li, Weifeng; Mu, Yuguang

    2012-02-01

    It has been a long history that urea and guanidinium chloride (GdmCl) are used as agents for denaturing proteins. The underlying mechanism has been extensively studied in the past several decades. However, the question regarding why GdmCl is much stronger than urea has seldom been touched. Here, through molecular dynamics simulations, we show that a 4 M GdmCl solution is more able than 7 M urea solution to dissociate both hydrophobic and charged nano-particles (NP). Both urea and GdmCl affect the NPs' aggregation through direct binding to the NP surface. The advantages of GdmCl originate from the net charge of bound guanidinium ions which can generate a local positively charged environment around hydrophobic and negatively charged NPs. This effective coating can introduce Coulombic repulsion between all the NPs. Urea shows certain ability to dissociate hydrophobic NPs. However, in the case of charged NPs, urea molecules located between two opposite-charged NPs will form ordered hydrogen bonds, acting like ``glue'' which prevents separation of the NPs. Although urea can form hydrogen bonds with either hydrophilic amino acids or the protein backbone, which are believed to contribute to protein denaturation, our findings strongly suggest that this property does not always contribute positively to urea's denaturation power.

  4. Antiamoebic chemoprophylaxis using quinfamide in children: a comparative study.

    PubMed

    Padilla, Nicolas; Diaz, Rosalinda; Alarcon, Alfonso; Barreda, Roberto

    2002-04-20

    This study sought to examine whether the administration of quinfamide at 3- or 6-month intervals diminished the frequency of Entamoeba histolytica cysts in stool samples compared to controls. The prospective, longitudinal, randomized, single-blind study examined children from six primary schools in Celaya and Neutla, Guanajuato. Of the 1,524 students in these schools, we selected participants for the study as follows: Children were included in the study if their parents agreed in writing to the study and if the children demonstrated evidence of E. histolytica cysts after a parasitoscopic analysis by concentration (PSC) in three samples over consecutive days using Faust"s method. Those included in the study received a single 4.3-g/kg dose of quinfamide, and we performed PSC on days 5, 6, and 7 following dose administration to examine whether quinfamide had affected the presence of the cysts. The study participants who tested negative for cysts were divided into three groups: Group 1 had 102 patients who underwent quinfamide treatment and three CPS analyses after the 12 months of the study; Group 2 had 98 subjects who underwent the quinfamide treatment and three CPS analyses at months 3, 6, 9, and 12 after their entrance into the study; and Group 3 had 102 patients, who underwent the quinfamide treatment and series of three CPS analyses at months 6 and 12 of the study. All participants received the dose of quinfamide after providing stool samples and after a clinical gastrointestinal history was obtained. Further clinical gastrointestinal data were collected 5 days after the quintamide dose was administered. We used EpiInfo 6.0 for statistical analysis, calculating c2 and p values for the clinical data and the CPS data after the 12 months concluded. Of the initial samples of 1,524 subjects, 308 (20.2%) had Entamoebic cysts. Of these, six were further eliminated because they did not meet the inclusion requirements. At the conclusion of the study, Group 1 presented

  5. A study of children's taste and visual preferences in dentifrices.

    PubMed

    Spear, C S; Savisky, L A

    1991-01-01

    Variables and gimmicks can make choosing a dentifrice for a child complicated. Various flavors, colors, shapes, consistency, labelling, and type of dispensers provide a constellation of choices for the consumer. This study sought to determine whether children actually prefer the dentifrices designed for them. Visually the child-oriented products were preferred; modern containers were preferred over the traditional. In terms of taste, however, "child-flavored" dentifrices were not preferred over the regular flavor of the same brand, when one is tasted after the other. PMID:1939794

  6. [The mother figure of children with malformations. A phenomenological study].

    PubMed

    Pinheiro, M C

    1997-01-01

    The theme of this research refers to children suffering congenital malformation through an analysis of their mothers' reactions in dealing with such a situation. It deals with a descriptive study along the qualitative line through the phenomenological approach. In order to attain that purpose, interviews were made and data collected. The analysis was built under the view of meaning, the orientation of those mothers, i.e. the outlook of the world from their perspective, which was tracked from the meanings (units of meaning) to actual sense based on the philosophical insight of Dr. Martin Heidegger, aiming at characterizing the mother-being in her daily life. PMID:9775933

  7. Children Rights in Social Studies Curricula in Elementary Education: A Comparative Study

    ERIC Educational Resources Information Center

    Merey, Zihni

    2012-01-01

    Social studies classes educate students as citizens who are expected to adopt democratic values and apply their information and richness to their life. Social studies classes are the ones that include human rights education in the first place. The purpose of this study is to make a comparison of inclusion levels of children's rights issues in…

  8. Systematic identification and intervention for reading difficulty: case studies of children with EAL.

    PubMed

    Fawcett, A J; Lynch, L

    2000-01-01

    Literacy underpins education. There is now very widespread concern over standards of literacy for children from multi-cultural backgrounds, who are learning English as a second or subsequent language, and who may have special educational needs. Research evidence suggests that the earlier children's difficulties can be identified, the more effective (and cost-effective) intervention will be, provided that the intervention is tailored to the child's abilities and skills. Nicolson and Fawcett have developed systematic procedures for identifying children at risk for reading difficulty, together with systematic teaching strategies to overcome reading difficulty. In this paper we present case studies of children with EAL (English as an additional language) drawn from a controlled study using computer interventions with secondary school children. Our findings indicate that children with EAL may be more resistant to remediation than some children with learning difficulties. The prognosis is more problematic for children with both EAL and dyslexia. PMID:10840507

  9. 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.

  10. Secondary Preventive Interventions with Preschool Children: A Follow-up Study.

    ERIC Educational Resources Information Center

    Rickel, Annette U.; Dyhdalo, Louise L.

    The long term effects of a preschool intervention program for an experimental group of high-risk, black, low income children were assessed and compared to a high-risk placebo control group and low-risk "normal" controls. Seventy first grade children were involved in this 2-year follow-up study. Of these children, 42 were involved in the preschool…

  11. Differential Use of the Open Classroom: A Study of Exploratory and Cautious Children. Final Report.

    ERIC Educational Resources Information Center

    Minuchin, Patricia

    The purpose of this study was to investigate the differences between exploratory children and cautious children as they functioned in open classrooms over a period of time and to document some general aspects of child behavior in open educational settings. Sixty children were observed through the course of the school year in their first grade open…

  12. The Impact of War on the Mental Health of Children: A Salvadoran Study.

    ERIC Educational Resources Information Center

    Walton, Joan Riley; Nuttall, Ronald L.; Nuttall, Ena Vazquez

    1997-01-01

    A study of 54 Salvadoran children (age 12), born in the Salvadoran Civil War, found the personal/social impact of the war was more important than family togetherness or war intensity in determining the mental health of the children. Children's intelligence was highly related to surviving with greater mental health. (Author/CR)

  13. Everyday Segregation amongst Disabled Children and Their Peers: A Qualitative Longitudinal Study in Norway

    ERIC Educational Resources Information Center

    Ytterhus, Borgunn

    2012-01-01

    This article is based on a qualitative longitudinal study of children's changing peer relationships through childhood, with particular emphasis on experiences of disabled children. Initial observation of face-to-face-encounters among children in school made us aware of social inclusion and exclusion mechanisms relating to informal interaction…

  14. Children's School Performance and Their Parents' Causal Attributions to Ability and Effort: A Longitudinal Study

    ERIC Educational Resources Information Center

    Natale, Katja; Aunola, Kaisa; Nurmi, Jari-Erik

    2009-01-01

    The present study investigated the cross-lagged associations between parents' attributions of ability and effort concerning their children's success and failure, and children's academic performance in kindergarten and primary school. Two hundred seven children and their parents were followed over three years. The parents completed a questionnaire…

  15. Multiracial Children and Poverty: Evidence from the Early Childhood Longitudinal Study of Kindergartners

    ERIC Educational Resources Information Center

    Bratter, Jenifer; Kimbro, Rachel Tolbert

    2013-01-01

    Despite the recent growth in multiracial children among American children, we know very little about their well-being. Using the Early Childhood Longitudinal Study, Kindergarten Class (N?=?17,706), we evaluated the likelihood of living in poverty and near poverty for multiracial and monoracial children. Most multiracial groups have poverty or near…

  16. Air Pollution, Cognitive Deficits and Brain Abnormalities: A Pilot Study with Children and Dogs

    ERIC Educational Resources Information Center

    Calderon-Garciduenas, Lilian; Mora-Tiscareno, Antonieta; Ontiveros, Esperanza; Gomez-Garza, Gilberto; Barragan-Mejia, Gerardo; Broadway, James; Chapman, Susan; Valencia-Salazar, Gildardo; Jewells, Valerie; Maronpot, Robert R.; Henriquez-Roldan, Carlos; Perez-Guille, Beatriz; Torres-Jardon, Ricardo; Herrit, Lou; Brooks, Diane; Osnaya-Brizuela, Norma; Monroy, Maria E.; Gonzalez-Maciel, Angelica; Reynoso-Robles, Rafael; Villarreal-Calderon, Rafael; Solt, Anna C.; Engle, Randall W.

    2008-01-01

    Exposure to air pollution is associated with neuroinflammation in healthy children and dogs in Mexico City. Comparative studies were carried out in healthy children and young dogs similarly exposed to ambient pollution in Mexico City. Children from Mexico City (n:55) and a low polluted city (n:18) underwent psychometric testing and brain magnetic…

  17. Understanding Children's Sedentary Behaviour: A Qualitative Study of the Family Home Environment

    ERIC Educational Resources Information Center

    Granich, Joanna; Rosenberg, Michael; Knuiman, Matthew; Timperio, Anna

    2010-01-01

    Electronic media (EM) (television, electronic games and computer) use has been associated with overweight and obesity among children. Little is known about the time spent in sedentary behaviour (SB) among children within the family context. The aim of this study was to explore how the family home environment may influence children's…

  18. Study of Support Services for Children with Special Needs in the State of Sikkim

    ERIC Educational Resources Information Center

    Dash, Neena

    2009-01-01

    The purpose of this paper is to present the status of integrated education for children with special needs in the State of Sikkim, to study the various support services required for children with special needs for their successful completion of primary education, to ascertain the academic support provided to children with special needs in the…

  19. How Children Learn the Ins and Outs: A Training Study of Toddlers' Categorization of Animals

    ERIC Educational Resources Information Center

    Lawson, Chris A.; Fisher, Anna V.; Rakison, David H.

    2015-01-01

    Young children are able to categorize animals on the basis of unobservable features such as shared biological properties (e.g., bones). For the most part, children learn about these properties through explicit verbalizations from others. The present study examined how such input impacts children's learning about the properties of categories. In a…

  20. Traumatic Responding in Children Exposed to Domestic Violence: A Cross-Cultural Study.

    ERIC Educational Resources Information Center

    Lehmann, Peter; Elliston, Ellen J.

    2001-01-01

    A study examined posttraumatic stress disorder in Mexican, Mexican American, and non-Mexican American children exposed to domestic violence. Surveys of 68 mothers with children in shelters in Mexico and Texas revealed no ethnic differences in children's overall trauma symptoms. Mothers' experience of physical and sexual abuse predicted greater…

  1. A Study of Reading Comprehension in Older Children Using Selected Korean Bible Translations

    ERIC Educational Resources Information Center

    Kim, Jae Woo

    2014-01-01

    Problem: The problem of this study was to determine the difference in Bible comprehension scores among gender-based groups of older children using selected passages from three Bible translations: the Children's Bible, the Easy Bible, and the New Revised Korean Bible. Procedures: A total of 288 older children in three churches (Beautiful Baptist…

  2. Forgotten "Native Americans": A Study of the Psychological Development of Hawaiian Children.

    ERIC Educational Resources Information Center

    D'Andrea, Michael; Daniels, Judy

    This study was conducted to learn more about the moral development of Hawaiian children and adolescents and to assess if grade level (grade 5, 7, 9, or 11) or gender were related to the children's reported level of self-esteem. Eighty Hawaiian children and adolescents from low-to middle-income families were interviewed individually, asked to solve…

  3. Timing of Mother and Child Depression in a Longitudinal Study of Children at Risk.

    ERIC Educational Resources Information Center

    Hammen, Constance; And Others

    1991-01-01

    Examined temporal associations of diagnoses in mothers and children in 3-year longitudinal study of unipolar, bipolar, and comparison women and their 8- to 16-year-old children. Found significant temporal association between mother and child diagnoses, especially in unipolar families, and most children who experienced major depressive episode did…

  4. A Longitudinal Study of the Development of Stop Consonant Production in Normal and Down's Syndrome Children.

    ERIC Educational Resources Information Center

    Smith, Bruce L.; Stoel-Gammon, Carol

    1983-01-01

    The longitudinal study of four normal children, 18 to 36 months old, and five Down's syndrome (DS) children, 3 to 6 years old, analyzed the development of stop consonants and stop clusters. Although similar sound patterns were observed for the two groups, the DS children showed considerable performance delay. (DB)

  5. Study of Level of Stress in the Parents of Children with Attention-Deficit/Hyperactivity Disorder

    ERIC Educational Resources Information Center

    Sethi, Sujata; Gandhi, Raghu; Anand, Vidhu

    2012-01-01

    Background: Parents who have children with attention-deficit hyperactivity disorder (ADHD) often experience high level of stress related to caring for their children. But not much research has been conducted in this area in India. This study aimed to assess the stress of parenting children with ADHD. Methods: This is a clinic based comparative…

  6. Friends' Responses to Children's Disclosure of an Achievement-Related Success: An Observational Study

    ERIC Educational Resources Information Center

    Altermatt, Ellen Rydell; Ivers, Ivy E.

    2011-01-01

    This study examined social support processes in the context of positive events. The conversations of fourth-grade through sixth-grade focal children and their friends (N = 116) were observed after focal children outperformed their friend on an achievement-related task. Changes in focal children's performance-related positive affect from…

  7. Incidence of Dysarthria in Children with Cerebellar Tumors: A Prospective Study

    ERIC Educational Resources Information Center

    Richter, S.; Schoch, B.; Ozimek, A.; Gorissen, B.; Hein-Kropp, C.; Kaiser, O.; Hovel, M.; Wieland, R.; Gizewski, E.; Timmann, D.

    2005-01-01

    The present study investigated dysarthric symptoms in children with cerebellar tumors. Ten children with cerebellar tumors and 10 orthopedic control children were tested prior and one week after surgery. Clinical dysarthric symptoms were quantified in spontaneous speech. Syllable durations were analyzed in syllable repetition and sentence…

  8. Parenting Stress and Social Support in Hearing Mothers of Deaf and Hearing Children: A Longitudinal Study.

    ERIC Educational Resources Information Center

    Lederberg, Amy R.; Golbach, Traci

    2002-01-01

    A study involving 23 mothers of children with deafness and 23 controls investigated the impact of child deafness on stress, social networks, and social support satisfaction. When children were 22 months, mothers of children with deafness expressed more stress, however at ages 3 and 4, stress was comparable to controls. (Contains references.)…

  9. Report of the Task Force to Study Strategies to Support Parents as Children's First Teachers. Revised.

    ERIC Educational Resources Information Center

    Maine State Dept. of Human Services, Augusta.

    The state of Maine has made a commitment to expand current programs for families with young children to ensure that the state is doing all that it can to help children reach their highest potential. This document is comprised of the June 1998 report of a Maine task force to study strategies to support parents as children's first teachers and the…

  10. A Longitudinal Study of Pragmatic Language Development in Three Children with Cochlear Implants

    ERIC Educational Resources Information Center

    Dammeyer, Jesper

    2012-01-01

    Research has shown how cochlear implants (CIs), in children with hearing impairments, have improved speech perception and production, but very little is known about the children's pragmatic language development. During a 4-year longitudinal study of three children with CIs, certain aspects of pragmatic language development were observed in free…

  11. The Role of Children's Appraisals on Adjustment Following Psychological Maltreatment: A Pilot Study

    ERIC Educational Resources Information Center

    Leeson, Fiona J.; Nixon, Reginald D. V.

    2011-01-01

    Little is known about the cognitive mechanisms involved in the development of psychopathology following psychological maltreatment in children. This study therefore examined the role of thinking styles on children's outcomes following this subtype of maltreatment. Children who had experienced past maltreatment (n = 24) and a control group (n = 26)…

  12. Working Memory, Attention, and Mathematical Problem Solving: A Longitudinal Study of Elementary School Children

    ERIC Educational Resources Information Center

    Swanson, H. Lee

    2011-01-01

    The role of working memory (WM) in children's growth in mathematical problem solving was examined in a longitudinal study of children (N = 127). A battery of tests was administered that assessed problem solving, achievement, WM, and cognitive processing (inhibition, speed, phonological coding) in Grade 1 children, with follow-up testing in Grades…

  13. Text-Messaging Practices and Links to General Spelling Skill: A Study of Australian Children

    ERIC Educational Resources Information Center

    Bushnell, Catherine; Kemp, Nenagh; Martin, Frances Heritage

    2011-01-01

    This study investigated 10- to 12-year-old Australian children's text-messaging practices and their relationship to traditional spelling ability. Of the 227 children tested, 82% reported sending text-messages; a median of 5 per day. Use of predictive and multi-press entry methods was roughly equal. Children produced a wide range of text-message…

  14. A Case Study of Three Children's Original Interpretations of the Moon's Changing Appearance

    ERIC Educational Resources Information Center

    Wilhelm, Jennifer

    2009-01-01

    A case study of three children was conducted to shed light on the process that children undergo in developing their understanding of physical phenomena. Using the notion of spontaneous construction and its relationship with school learning of scientific concepts, children's early thoughts of the moon's appearance were explored. Research questions…

  15. Perceived Racism and Discrimination in Children and Youths: An Exploratory Study

    ERIC Educational Resources Information Center

    Pachter, Lee M.; Bernstein, Bruce A.; Szalacha, Laura A.; Garcia Coll, Cynthia

    2010-01-01

    Racism may be a factor contributing to poor health and health care disparities in minority children through multiple mechanisms, including effects on psychological and physical well-being. Little is known about the experiences of racism that children encounter in their lives. This study describes the occurrences of perceived racism in children,…

  16. Narrative Comprehension and Production in Children with SLI: An Eye Movement Study

    ERIC Educational Resources Information Center

    Andreu, Llorenc; Sanz-Torrent, Monica; Olmos, Joan Guardia; MacWhinney, Brian

    2011-01-01

    This study investigates narrative comprehension and production in children with specific language impairment (SLI). Twelve children with SLI (mean age 5;8 years) and 12 typically developing children (mean age 5;6 years) participated in an eye-tracking experiment designed to investigate online narrative comprehension and production in Catalan- and…

  17. Guidelines for studying developmental prosopagnosia in adults and children.

    PubMed

    Dalrymple, Kirsten A; Palermo, Romina

    2016-01-01

    Developmental prosopagnosia (DP) is a neurodevelopmental condition characterized by severe face identity recognition problems that results from a failure to develop the mechanisms necessary for adequate face processing (Duchaine BC, Nakayama K. Developmental prosopagnosia: a window to content-specific face processing. Curr Opin Neurobiol 2006, 16:166-173.). It occurs in children and adults with normal visual acuity, and without intellectual impairments or known brain injuries. Given the importance of face recognition in daily life, and the detrimental effects of impaired face recognition, DP is an important area of study. Yet conventions for classifying individuals as DP for research purposes are poorly defined. In this focus paper, we discuss: (1) criteria for an operational definition of DP; 2) tests of face recognition and conventions for classifying individuals as DP; and 3) important considerations regarding common associations and dissociations, and cognitive heterogeneity in DP. We also highlight issues unique to studying DP in children, a relatively new endeavor that is proving to be an important complement to the work with adults. Ultimately, we hope to identify challenges researchers face when studying DP, and offer guidelines for others to consider when embarking on their own research pursuits on the topic. For further resources related to this article, please visit the WIREs website. PMID:26681428

  18. Cohort Profile: The Study of Respiratory Pathogens in Andean Children

    PubMed Central

    Grijalva, Carlos G; Griffin, Marie R; Edwards, Kathryn M; Williams, John V; Gil, Ana I; Verastegui, Héctor; Hartinger, Stella M; Vidal, Jorge E; Klugman, Keith P; Lanata, Claudio F

    2014-01-01

    We investigated respiratory pathogens in a prospective cohort study of young children living in the Peruvian Andes. In the study we assessed viral respiratory infections among young children, and explored interactions of viruses with common respiratory bacteria, especially Streptococcus pneumoniae. Through weekly household visits, data were collected on the signs and symptoms of acute respiratory illness (ARI), nasal samples were collected to test for viruses during episodes of ARI, and nasopharyngeal samples were collected on a monthly basis to monitor bacterial colonisation. We also collected data on vaccination coverage, patterns of social mixing, geographic information, and environmental and socio-demographic variables. Understanding the interaction of respiratory viruses with bacteria and its impact on the burden and severity of ARIs in rural areas of developing countries is critical to designing strategies for preventing such infections. Investigators interested in more details about this study or in accessing these resources should contact Dr. Carlos G. Grijalva at Vanderbilt University (carlos.grijalva@vanderbilt.edu). PMID:23771719

  19. Pharmacogenetic studies in children with acute lymphoblastic leukemia in Argentina.

    PubMed

    Aráoz, Hilda Verónica; D'Aloi, Karina; Foncuberta, María Eugenia; Sanchez La Rosa, Christian Germán; Alonso, Cristina Noemí; Chertkoff, Lilien; Felice, Marisa

    2015-05-01

    The aim of this study was to evaluate the influence of the most common genetic variants in methylenetetrahydrofolate reductase (MTHFR), thiopurine methyltransferase (TPMT) and glutathione-S-transferases (GSTs) on the outcome of acute lymphoblastic leukemia (ALL) treatment in Argentinean children. Two hundred and eighty-six patients with ALL treated with two Berlin-Frankfurt-Münster (BFM)-based protocols were analyzed. Ten genetic variants were studied. Toxicity was evaluated during the consolidation phase. Children who received 2 g/m(2)/day of methotrexate and carried at least one 677T allele in MTHFR showed an increased risk of developing severe leukopenia (p = 0.004) and neutropenia (p = 0.003). Intermediate-risk (IR) patients with a heterozygous TPMT genotype had a higher probability of event-free survival than those with a wild-type genotype. Genotyping of MTHFR polymorphisms might be useful to optimize consolidation therapy, reducing the associated severe hematologic toxicity. Further studies are necessary to establish the usefulness of MTHFR and TPMT variants as additional markers to predict outcome in the IR group. PMID:25110820

  20. Acute Nonbacterial Gastroenteritis in Hospitalized Children: A Cross Sectional Study

    PubMed Central

    Shokrollahi, Mohammad Reza; Noorbakhsh, Samileh; Monavari, Hamid Reza; Ghavidel Darestani, Sahar; Vosoughi Motlagh, Ahmad; Javadi Nia, Shima

    2014-01-01

    Background: Viral acute gastroenteritis (AGE) is a major cause of morbidity in childhood and leads to hospitalization in developed countries, such as Iran. Objectives: The aim of this study was to determine the prevalence and viral types (rotavirus, adenovirus, human parechoviruses-1, and human bocavirus) of acute nonbacterial gastroenteritis in hospitalized children. Patients and Materials: This was a across-sectional prospective study performed at the Pediatric Department of Rasoul Hospital, Tehran, Iran (2009-2011) on 80 hospitalized children with viral AGE. All Stool samples were collected on viral transport media. Human bocavirus (HBoV) was detected using the Real-time PCR TaqMan method. Molecular detection of human parechovirus type 1 (HPeV-1) RNA in stool samples was done using a specific nested reverse transcription PCR (RT-PCR). Rota and adeno virus antigens were sought by rapid chromatographic tests. P values less than 0.05 were considered statistically significant. Results: Fever was determined in 47.5% of cases (38), nausea and vomiting in 42.5% (34), respiratory symptoms in 16.3% (13), abdominal pain in 76%. Duration of diarrhea was 1-30 days (mean = 6.3 + 4.3 days). No dehydration was observed in 43.5% of subjects, mild dehydration in 33.8%, moderate dehydration in 17.5% and severe dehydration in 5% of cases. Positive rotavirus was found in 48.8% of cases (39), adenovirus in 20% (16), HBoV in 8% (6) and HPeV-1 in 23.2% (19), and adeno and rotaviruses co-infection in 6% (4). The frequency of positive HBoV was significantly lower than adeno and rotaviruses infection (P value = 0.0001). Rotavirus was more frequent in males (P value = 0.003) and in young children (17.49 months vs. 21.44 months) [P value = 0.03, CI = -13.4, 5.5]. Rotavirus infection was related to the degree of dehydration (P value = 0.001) but was not related to the presence of vomiting or fever (P value > 0.5). Conclusions: This study indicates that viral agents, especially rotavirus (48

  1. Changes in autistic trait indicators in parents and their children with ASD: A preliminary longitudinal study.

    PubMed

    Hasegawa, Chiaki; Kikuchi, Mitsuru; Yoshimura, Yuko; Hiraishi, Hirotoshi; Munesue, Toshio; Takesaki, Natsumi; Higashida, Haruhiro; Oi, Manabu; Minabe, Yoshio; Asada, Minoru

    2015-08-30

    This study investigated whether the longitudinal changes in symptom severity in children with autism spectrum disorder (ASD) are associated with changes in the parents׳ autistic traits. The results demonstrated two significant correlations between the changes in children׳s Social Responsiveness Scale (SRS) scores and the Social Responsiveness Scale (SRS) score changes in either the father or both parents. Autistic symptom mitigation in ASD children was associated with increased empathy levels in their parents. PMID:26099658

  2. Project CAPER (Children and Parents Enjoy Reading): A Case Study.

    ERIC Educational Resources Information Center

    Wepner, Shelley B.; Caccavale, Philip P.

    1991-01-01

    Describes a school-home partnership for encouraging parents to read along with their children to promote reading as a part of children's everyday habits. Finds that using parents to model this behavior enhanced students' attitude toward reading. (MG)

  3. A PRIMER ON THE EPIDEMIOLOGIC FIELD STUDY OF YOUNG CHILDREN

    EPA Science Inventory

    Concern about children's environmental health is increasing as newly characterized risks are indentified. Often little data is available to guide policy decisions. Research on children's ambient exposures to environmental contaminants is essential to understand the magnitude ...

  4. 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.

  5. Study on the Calculation of Magnetic Force Based on the Equivalent Magnetic Charge Method

    NASA Astrophysics Data System (ADS)

    Li, Jiangang; Tan, Qingchang; Zhang, Yongqi; Zhang, Kuo

    Magnetic drivers have been used widely in the pharmaceutical, chemical, petroleum, food and other industries with its perfect sealing without contact. Common method of calculating of the magnetic force are the Maxwell equations, empirical formulas, and he equivalent magnetic charge method as well. The Maxwell equations method is the most complicated and the empirical formulas method is the simplest with low accuracy. The equivalent magnetic charge method is simpler than the Maxwell equations method and more accurate than the empirical formulas method. In this paper, the magnetic force of the magnetic driver of reciprocate in line is calculated with the equivalent magnetic charge method and was compared with the experiment.

  6. [A study of the necessity of cooling of charge-coupled devices in x-ray imaging systems].

    PubMed

    Morgun, O N; Nemchenko, K E; Rogov, Iu V

    2006-01-01

    The goal of this work was to study one of the widely used X-ray imaging systems: luminescent screen-optical system-matrix of photosensitive charge-coupled device (CCD)-amplifier-analog-to-digital converter. Experimental and theoretical studies were performed to substantiate the necessity of cooling of charge-coupled devices for improvement of X-ray image characteristics. The obtained results reveal the necessity of cooling of CCD-matrix crystals in the X-ray imaging system under consideration. PMID:16610280

  7. METHODS STUDIES FOR THE NATIONAL CHILDREN'S STUDY: MOLECULARLY IMPRINTED POLYMERS

    EPA Science Inventory

    Accurate exposure classification tools are required to link exposure with health effects in epidemiological studies. Although long-term integrated exposure measurements are a critical component of exposure assessment, the ability to include these measurements into epidemiologic...

  8. 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.

  9. X-ray Diffuse Scattering Study of the Pinning of Charge Density Waves

    NASA Astrophysics Data System (ADS)

    Ravy, Sylvain; Rouzière, Stéphan; Moret, Roger; Pouget, Jean-Paul

    1997-03-01

    We have used the X-ray "White Line" interference effect(S. Ravy and J.-P Pouget, J. Phys. (France), 3, 109 (1993)) to study the pinning of 2k_f-charge density wave (CDW) in the blue bronze K_0.3MoO3 and the transition metal trichalcogenide NbSe_3. When a CDW is pinned to impurities, the coherence between the position of the impurity and the phase of the periodic lattice distortion associated to the CDW gives rise to an asymmetry of the intensity of the pair of G+2kf and G-2kf satellite reflections. In organic systems like TTF-TCNQ, a huge asymmetry has been observed in the high temperature fluctuating phase(S. Brazovskii et al, accepted in Phys. Rev. B). This asymmetry is weaker in inorganic materials. It shows that in Vanadium-doped blue bronzes and Titanium-doped NbSe_3, the pinning is strong, while in Tungsten-doped blue bronzes, a more subtle situation occurs. Moreover, the sense of the asymmetry allows us to determine the phase of the CDW at the impurity site. This phase in found to be consistent with an electronic pinning of the CDW. In blue bronzes, synchrotron radiation study of the asymmetry of the satellite profiles gives evidence for a deformation of the CDW-phase around the impurity.

  10. The uses of electron beam ion traps in the study of highly charged ions

    SciTech Connect

    Knapp, D.

    1994-11-02

    The Electron Beam Ion Trap (EBIT) is a relatively new tool for the study of highly charged ions. Its development has led to a variety of new experimental opportunities; measurements have been performed with EBITs using techniques impossible with conventional ion sources or storage rings. In this paper, I will highlight the various experimental techniques we have developed and the results we have obtained using the EBIT and higher-energy Super-EBIT built at the Lawrence Livermore National Laboratory. The EBIT employs a high-current-density electron beam to trap, ionize, and excite a population of ions. The ions can be studied in situ or extracted from the trap for external experiments. The trapped ions form an ionization-state equilibrium determined by the relative ionization and recombination rates. Ions of several different elements may simultaneously be present in the trap. The ions are nearly at rest, and, for most systems, all in their ground-state configurations. The electron-ion interaction energy has a narrow distribution and can be varied over a wide range. We have used the EBIT devices for the measurement of electron-ion interactions, ion structure, ion-surface interactions, and the behavior of low-density plasmas.

  11. 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.

  12. Theoretical study of the charge transport through C60-based single-molecule junctions

    NASA Astrophysics Data System (ADS)

    Bilan, S.; Zotti, L. A.; Pauly, F.; Cuevas, J. C.

    2012-05-01

    We present a theoretical study of the conductance and thermopower of single-molecule junctions based on C60 and C60-terminated molecules. We first analyze the transport properties of gold-C60-gold junctions and show that these junctions can be highly conductive (with conductances above 0.1G0, where G0=2e2/h is the quantum of conductance). Moreover, we find that the thermopower in these junctions is negative due to the fact that the lowest unoccupied molecular orbital dominates the charge transport, and its magnitude can reach several tens of microvolts per kelvin, depending on the contact geometry. On the other hand, we study the suitability of C60 as an anchoring group in single-molecule junctions. For this purpose, we analyze the transport through several dumbbell derivatives using C60 as anchors, and we compare the results with those obtained with thiol and amine groups. Our results show that the conductance of C60-terminated molecules is rather sensitive to the binding geometry. Moreover, the conductance of the molecules is typically reduced by the presence of the C60 anchors, which in turn makes the junctions more sensitive to the functionalization of the molecular core with appropriate side groups.

  13. Internet Surfing for Kindergarten Children: A Feasibility Study

    ERIC Educational Resources Information Center

    Loo, Alfred

    2012-01-01

    The Internet is an effective learning tool for gifted children because it allows them to independently select the areas in which they have talent. The Internet also enables children to discover and maximize their potential. However, younger children might not have a large enough vocabulary to surf the Internet, even if they are gifted. For…

  14. A Historical Study of Children's Heroes and Fantasy Play.

    ERIC Educational Resources Information Center

    French, Judy

    Is the superhero that preschool children emulate and dramatize in their play qualitatively different from the heroes of children in the past? To answer this question, data were gathered (1) from a historical review of the literature on children's play and their heroes and (2) from a survey questionnaire completed by 100 subjects stratified to…

  15. Children's Perceptions of Live Arts Performances: A Longitudinal Study

    ERIC Educational Resources Information Center

    Schiller, Wendy

    2005-01-01

    "Children?s Voices" is a longitudinal research project to document and understand children's perceptions of live arts performance and the impact on their teachers and school communities. The research conducted in South Australia with 135 5?12-year-olds in four schools involves collaboration between the South Australian Department of Education and…

  16. Special Education Experiences of Foster Children: An Empirical Study.

    ERIC Educational Resources Information Center

    Goerge, Robert M.; And Others

    1992-01-01

    Compared the demographic characteristics of and the special education services received by Illinois children who are in both foster care and special education programs, with those of children in only one of these systems. Presents information on the handicaps of foster children served by the special education system. (SM)

  17. Space charge in proton linacs

    SciTech Connect

    Wangler, T. P.; Merrill, F.; Rybarcyk, L.; Ryne, R.

    1998-11-05

    Space charge effects on beam dynamics in linear accelerators are discussed. Practical linac beam dynamics calculation methods which include space charge effects are discussed. Also, the status of beam performance experiments including space charge studies are summarized.

  18. Orbital dependent ultrafast charge transfer dynamics of ferrocenyl-functionalized SAMs on gold studied by core-hole clock spectroscopy

    NASA Astrophysics Data System (ADS)

    Cao, Liang; Yang, Ming; Yuan, Li; Nerngchamnong, Nisachol; Feng, Yuan-Ping; Wee, Andrew T. S.; Qi, Dong-Chen; Nijhuis, Christian A.

    2016-03-01

    Understanding the charge transport properties in general of different molecular components in a self-assembled monolayer (SAM) is of importance for the rational design of SAM molecular structures for molecular electronics. In this study, we study an important aspect of the charge transport properties, i.e. the charge transfer (CT) dynamics between the active molecular component (in this case, the ferrocenyl moieties of a ferrocenyl-n-alkanethiol SAM) and the electrode using synchrotron-based core-hole clock (CHC) spectroscopy. The characteristic CT times are found to depend strongly on the character of the ferrocenyl-derived molecular orbitals (MOs) which mediate the CT process. Furthermore, by systemically shifting the position of the ferrocenyl moiety in the SAM, it is found that the CT characteristics of the ferrocenyl MOs display distinct dependence on its distance to the electrode. These results demonstrate experimentally that the efficiency and rate of charge transport through the molecular backbone can be modulated by resonant injection of charge carriers into specific MOs.

  19. Charging-circuit study for copper-vapor lasers. Final report, 29 June 1981-30 November 1981

    SciTech Connect

    Not Available

    1981-12-01

    This study is divided into three tasks whose combined purpose is to evaluate methods of charging high PRF pulsed power subsystems required in a proposed laser isotope separation (LIS) plant. The work performed in this program follows directly from designs and experiments carried out in a recently-completed study and, in fact, utilizes much of the same apparatus described previously. The first task required the preparation and vugraph presentation of a review of eight potential charging methods. This review and the associated evaluation criteria are described. Tasks II and III entailed the experimental evaluation of the deQing methods of regulating the charging voltage of a pulse power conditioning module with respect to limitations imposed by continuous operation and the efficiency of recovery of energy diverted by the deQing circuitry. The results of these tasks are described.

  20. Studies of charge neutral FCC Lattice Gas with Yukawa Interaction and Accelerated Cartesian Expansion method

    NASA Astrophysics Data System (ADS)

    Huang, He

    In this thesis, I present the results of studies of the structural properties and phase transition of a charge neutral FCC Lattice Gas with Yukawa Interaction and discuss a novel fast calculation algorithm---Accelerated Cartesian Expansion (ACE) method. In the first part of my thesis, I discuss the results of Monte Carlo simulations carried out to understand the finite temperature (phase transition) properties and the ground state structure of a Yukawa Lattice Gas (YLG) model. In this model the ions interact via the potential q iqjexp(-kappar> ij)/rij where qi,j are the charges of the ions located at the lattice sites i and j with position vectors R i and Rj; rij = Ri-Rj, kappa is a measure of the range of the interaction and is called the screening parameter. This model approximates an interesting quaternary system of great current thermoelectric interest called LAST-m, AgSbPbmTem+2. I have also developed rapid calculation methods for the potential energy calculation in a lattice gas system with periodic boundary condition bases on the Ewald summation method and coded the algorithm to compute the energies in MC simulation. Some of the interesting results of the MC simulations are: (i) how the nature and strength of the phase transition depend on the range of interaction (Yukawa screening parameter kappa) (ii) what is the degeneracy of the ground state for different values of the concentration of charges, and (iii) what is the nature of two-stage disordering transition seen for certain values of x. In addition, based on the analysis of the surface energy of different nano-clusters formed near the transition temperature, the solidification process and the rate of production of these nano-clusters have been studied. In the second part of my thesis, we have developed two methods for rapidly computing potentials of the form R-nu. Both these methods are founded on addition theorems based on Taylor expansions. Taylor's series has a couple of inherent advantages: (i) it

  1. Algorithms for verbal autopsies: a validation study in Kenyan children.

    PubMed Central

    Quigley, M. A.; Armstrong Schellenberg, J. R.; Snow, R. W.

    1996-01-01

    The verbal autopsy (VA) questionnaire is a widely used method for collecting information on cause-specific mortality where the medical certification of deaths in childhood is incomplete. This paper discusses review by physicians and expert algorithms as approaches to ascribing cause of deaths from the VA questionnaire and proposes an alternative, data-derived approach. In this validation study, the relatives of 295 children who had died in hospital were interviewed using a VA questionnaire. The children were assigned causes of death using data-derived algorithms obtained under logistic regression and using expert algorithms. For most causes of death, the data-derived algorithms and expert algorithms yielded similar levels of diagnostic accuracy. However, a data-derived algorithm for malaria gave a sensitivity of 71% (95% Cl: 58-84%), which was significantly higher than the sensitivity of 47% obtained under an expert algorithm. The need for exploring this and other ways in which the VA technique can be improved are discussed. The implications of less-than-perfect sensitivity and specificity are explored using numerical examples. Misclassification bias should be taken into consideration when planning and evaluating epidemiological studies. PMID:8706229

  2. Mirror therapy in children with hemiplegia: a pilot study.

    PubMed

    Gygax, Marine Jequier; Schneider, Patrick; Newman, Christopher John

    2011-05-01

    Mirror therapy, which provides the visual illusion of a functional paretic limb by using the mirror reflection of the non-paretic arm, is used in the rehabilitation of hemiparesis after stroke in adults. We tested the effectiveness and feasibility of mirror therapy in children with hemiplegia by performing a pilot crossover study in ten participants (aged 6-14 y; five males, five females; Manual Ability Classification System levels: one at level I, two at level II, four at level III, three at level IV) randomly assigned to 15 minutes of daily bimanual training with and without a mirror for 3 weeks. Assessments of maximal grasp and pinch strengths, and upper limb function measured by the Shriner's Hospital Upper Extremity Evaluation were performed at weeks 0 (baseline), 3, 6 (intervention), and 9 (wash-out). Testing of grasp strength behind the mirror improved performance by 15% (p=0.004). Training with the mirror significantly improved grasp strength (with mirror +20.4%, p=0.033; without +5.9%, p>0.1) and upper limb dynamic position (with mirror +4.6%, p=0.044; without +1.2%, p>0.1), while training without a mirror significantly improved pinch strength (with mirror +6.9%, p>0.1; without +21.9%, p=0.026). This preliminary study demonstrates the feasibility of mirror therapy in children with hemiplegia and that it may improve strength and dynamic function of the paretic arm. PMID:21410693

  3. A longitudinal study of very young children's vowel production

    PubMed Central

    McGowan, Rebecca W.; McGowan, Richard S.; Denny, Margaret; Nittrouer, Susan

    2014-01-01

    Purpose Ecologically realistic, spontaneous adult-directed longitudinal speech data of young children was described by acoustic analyses. Method The first two formant frequencies of vowels produced by six children from different American English dialect regions were analyzed from ages 18 to 48 months. The vowels were from largely conversational contexts and were classified according to dictionary pronunciation. Results Within-subject formant frequency variability remained relatively constant for the span of ages studied here. It was often difficult to detect overall decreases in the first two formant frequencies between the ages of 30 and 48 months. A study of the movement of the corner vowels with respect to the vowel centroid showed that the shape of the vowel space remained qualitatively constant from 30 through 48 months. Conclusions The shape of the vowel space is established early in life. Some aspects of regional dialect were observed in some of the subjects at 42 months of age. The present paper adds to the existing data on the development of vowel spaces by describing ecologically realistic speech. PMID:24687464

  4. Children of the atomic bomb survivors: A genetic study

    SciTech Connect

    Neel, J.V.; Schull, W.J.

    1991-01-01

    This volume represents the results of over 40 years of study of the latent health effects on the survivors of the atomic bomb blasts. Planning for this research began in 1946 and data collection has been ongoing since 1948. The work represents the efforts of both US and Japanese agencies and presents 13 papers which the editors believe represent the best scientific information related to the genetic effects of radiation exposure. In general, the results presented here indicate that radiation exposure effects on reproductive cells are less than previously thought. The paper contained here examine that question in light of effects on pregnancy outcome, sex ratio, congenital defects, and early mortality of children. The papers also present helpful comparison of these results with the results seen in experimental radiation studies with animals. For anyone interested in the risks associated with radiation studies, this book represents a vital collection of information.

  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. A study of kindergarten children's spatial representation in a mapping project

    NASA Astrophysics Data System (ADS)

    Davis, Genevieve A.; Hyun, Eunsook

    2005-02-01

    This phenomenological study examined kindergarten children's development of spatial representation in a year long mapping project. Findings and discussion relative to how children conceptualised and represented physical space are presented in light of theoretical notions advanced by Piaget, van Hiele, and cognitive science researchers Battista and Clements. Analyses of the processes the children used and their finished products indicate that children can negotiate meaning for complex systems of geometric concepts when given opportunities to debate, negotiate, reflect, evaluate and seek meaning for representing space. The complexity and "holistic" nature of spatial representation of young children emerged in this study.

  8. Asylum-seeking children's experiences of detention in Canada: A qualitative study.

    PubMed

    Kronick, Rachel; Rousseau, Cécile; Cleveland, Janet

    2015-05-01

    Children and parents seeking asylum are regularly detained in Canada, however little is known about the experiences of detained families. International literature suggests that the detention of children is associated with significant morbidity. Our study aims to understand the experiences of detained children and families who have sought asylum in Canada by using a qualitative methodology that includes semistructured interviews and ethnographic participant observation. Detention appears to be a frightening experience of deprivation that leaves children feeling criminalized and helpless. Family separation further shatters children's sense of well-being. Children's emotional and behavioral responses to separation and to detention suggest that the experience is acutely stressful and, in some cases, traumatic--even when detention is brief. Distress and impairment may persist months after release. Given the burden of psychological suffering and the harmful consequences of separating families, children should not be detained for immigration reasons and parents should not be detained without children. PMID:25985114

  9. 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.

  10. Caffeine Awareness in Children: Insights from a Pilot Study

    PubMed Central

    Thakre, Tushar P.; Deoras, Ketan; Griffin, Catherine; Vemana, Aarthi; Podmore, Petra; Krishna, Jyoti

    2015-01-01

    Study Objectives: Caffeine, a commonly consumed psychoactive substance, can have significant effects on sleep. Caffeine intake among children is increasing, mainly in the form of sodas. However, adolescent caffeine consumers may lack knowledge about the caffeine content in common beverages. If true, this very fact may hamper the assessment of the effects of caffeine consumption on sleep in children if such assessments are a priori dependent on responders being able to reliably distinguish between caffeinated and noncaffeinated beverages. This preliminary study investigated adolescents' caffeine knowledge and intake at a Cleveland-area public middle school. Methods: Seventh- and eighth-grade students were surveyed using: (1) the Caffeine Literacy and Sleep Study (CLASS), a 15-question pilot instrument designed to assess caffeine knowledge and intake by type, quantity and timing, as well as sleep habits; and (2) the Cleveland Adolescent Sleepiness Questionnaire (CASQ), a validated survey measuring excessive daytime sleepiness in adolescents. These questionnaires were distributed and collected during a specified class period. Results: Of the 635 seventh- and eighth-grade students who attended school on the day of the study, 555 (87%) participated. Lack of knowledge about caffeine content of particular drinks was noted in seventh and eighth graders of both sexes with nearly 29% unaware that their favorite drinks contain caffeine and more than 50% unable to correctly identify the drinks with the most caffeine. A low percentage of students correctly identified light-colored sodas lacking caffeine: 7-Up (24.1%), Sierra Mist (38.9%), ginger ale (39.8%), Sprite (39.8%), and Fresca (53.7%). The percentages of students correctly identifying caffeinated light-colored beverages were: Arizona Green Tea (43.5%), Mello Yellow (50.9%), and A&W cream soda (67.6%). However, Mountain Dew was correctly identified by most (93.5%) as caffeinated. Conclusions: Students were not

  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

    2015-01-01

    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. PMID:26263086

  12. Scanning capacitance microscope study of a SiO2/Si interface modified by charge injection

    NASA Astrophysics Data System (ADS)

    Tomiye, H.; Yao, T.

    We have investigated the local electrical properties of an SiO2/Si structure using a scanning capacitance microscope (SCaM) combined with an atomic force and a scanning tunneling microscope (AFM and STM). The electrical properties of the Si substrate and the SiO2/Si interface vary with position. In this experiment we have injected charge into the SiO2 and investigated the nature of charge storage at the SiO2/Si interface. We have used the combined microscope to apply a pulse to the SiO2/Si sample, causing charge to be trapped in the SiO2/Si interface. We could clearly detect the local variation of interface charge in a non-destructive manner using the SCaM and simultaneously by capacitance-voltage (C-V) characterization. The volume of the C-V curve shift along the voltage axis due to trapped charges is dependent upon the density of the trapped charges. In doing this experiment we show one of the many possible applications of the combined SCaM/AFM/STM.

  13. 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.

  14. Cross-Cultural Studies on Cognitive Development of Chinese Children from Different Nationalities.

    ERIC Educational Resources Information Center

    Menglan, Zuo; Chang, Wei

    Reviewed are recent studies of the cognitive development of Chinese children. The discussion identifies: (1) systematic studies of children's cognitive development; (2) studies on the development of thinking; (3) studies of memory development; and (4) studies on the influences of various national cultures and education on the development of…

  15. A comparison study of educational involvement of hearing parents of deaf and hearing children of elementary school age.

    PubMed

    Powers, G W; Saskiewicz, J A

    1998-03-01

    This study was conducted to determine if a difference exists in level of educational involvement between hearing parents of deaf children and hearing parents of hearing children. Participating parents were asked to complete a 23-question survey about their involvement in their children's education over the past year. Neither group of parents demonstrated a significantly higher level of involvement in their children's education. However, parents of deaf children observed their children in the classroom more than parents of hearing children; parents of hearing children volunteered in their child's classroom more than parents of deaf children. PMID:9557331

  16. Charge separation and energy transfer in the photosystem II core complex studied by femtosecond midinfrared spectroscopy.

    PubMed

    Pawlowicz, N P; Groot, M-L; van Stokkum, I H M; Breton, J; van Grondelle, R

    2007-10-15

    The core of photosystem II (PSII) of green plants contains the reaction center (RC) proteins D1D2-cytb559 and two core antennas CP43 and CP47. We have used time-resolved visible pump/midinfrared probe spectroscopy in the region between 1600 and 1800 cm(-1) to study the energy transfer and charge separation events within PSII cores. The absorption difference spectra in the region of the keto and ester chlorophyll modes show spectral evolution with time constants of 3 ps, 27 ps, 200 ps, and 2 ns. Comparison of infrared (IR) difference spectra obtained for the isolated antennas CP43 and CP47 and the D1D2-RC with those measured for the PSII core allowed us to identify the features specific for each of the PSII core components. From the presence of the CP43 and CP47 specific features in the spectra up to time delays of 20-30 ps, we conclude that the main part of the energy transfer from the antennas to the RC occurs on this timescale. Direct excitation of the pigments in the RC evolution associated difference spectra to radical pair formation of PD1+PheoD1- on the same timescale as multi-excitation annihilation and excited state equilibration within the antennas CP43 and CP47, which occur within approximately 1-3 ps. The formation of the earlier radical pair ChlD1+PheoD1-, as identified in isolated D1D2 complexes with time-resolved mid-IR spectroscopy is not observed in the current data, probably because of its relatively low concentration. Relaxation of the state PD1+PheoD1-, caused by a drop in free energy, occurs in 200 ps in closed cores. We conclude that the kinetic model proposed earlier for the energy and electron transfer dynamics within the D1D2-RC, plus two slowly energy-transferring antennas C43 and CP47 explain the complex excited state and charge separation dynamics in the PSII core very well. We further show that the time-resolved IR-difference spectrum of PD1+PheoD1- as observed in PSII cores is virtually identical to that observed in the isolated D1D2-RC

  17. Charge Transport in Molecular Junctions: A Study of Level-Alignment, Thermoelectric Properties, and Environmental Effects

    NASA Astrophysics Data System (ADS)

    Kotiuga, Michele

    Here, we use and develop first-principles methods based on density functional theory (DFT) and beyond to understand and predict charge transport phenomena in the novel class of nanostructured devices: molecular junctions. Molecular junctions, individual molecules contacted to two metallic leads, which can be systematically altered by modifying the chemistry of each component, serve as test beds for the study of transport at the nanoscale. To date, various experimental methods have been designed to reliably assemble and measure transport properties of molecular junctions. Furthermore, theoretical methods built on DFT designed to yield quantitative agreement with these experiments for certain classes of molecular junctions have been developed. In order to gain insight into a broader range of molecular junctions and environmental effects associated with the surrounding solution, this dissertation will employ, explore and extend first-principles DFT calculations coupled with approximate self-energy corrections known to yield quantitative agreement with experiments for certain classes of molecular junctions. To start we examine molecular junctions in which the molecule is strongly hybridized with the leads: a challenging limit for the existing methodology. Using a physically motivated tight-binding model, we find that the experimental trends observed for such molecules can be explained by the presence of a so-called "gateway" state associated with the chemical bond that bridges the molecule and the lead. We discuss the ingredients of a self-energy corrected DFT based approach to quantitatively predict conductance in the presence of these hybridization effects. We also develop and apply an approach to account for the surrounding environment on the conductance, which has been predominantly ignored in past transport calculations due to computational complexity. Many experiments are performed in a solution of non-conducting molecules; far from benign, this solution is known

  18. Stereoacuity and Related Factors: The Shandong Children Eye Study

    PubMed Central

    Hu, Yuan-yuan; Sun, Wei; Lv, Tai-liang; Jiang, Wen-jun; Wu, Hui; Wang, Xing-rong; Bi, Hong-sheng

    2016-01-01

    Objective To assess stereoacuity in a population-based sample of children and to examine ocular and systemic parameters related to stereoacuity. Methods Using a random cluster sampling method, four- to 18-year-old children from kindergartens, elementary schools, junior high schools and senior high schools from a rural area and an urban area in the East Chinese province of Shandong were included in the school-based cross-sectional study. All participants underwent a comprehensive eye examination including assessment of cycloplegic refraction and measurement of stereoacuity using the Titmus Stereo test. Results Out of 6364 eligible children, 5780 (90.8%) children with a mean age of 10.1 ± 3.2 years (range: 4 to 18 years) participated. Mean (± standard deviation) stereoacuity was 50.2 ± 50.6 arc seconds. Stereoacuity improved significantly (P<0.01) from the age group of 4 years to the age group of 6 to 7 years, then showed a plateau, deteriorated (P = 0.001) for both sexes from the age group of 9 years to the age group of 12 years (P<0.001), after which it improved (P = 0.001) again in the age group of 16 years or older to the pre-puberty values. In multivariate analysis, larger angle of binocular disparity (i.e., lower stereoacuity) was significantly associated with lower best corrected visual acuity (logMAR; P<0.001), higher intereye difference in refractive error (spherical equivalent) (P<0.001), higher cylindrical refractive error (P<0.001), higher refractive error (spherical value; P<0.001), higher intereye difference in best corrected visual acuity (logMAR) (P = 0.001), higher intereye difference in axial length (P = 0.001), and rural region of habitation (P = 0.006). Conclusions Stereoacuity as tested with the Titmus Stereo test improved significantly from an age of 4 years to an age of 6 and 7 years, then remained constant, temporarily deteriorated for both sexes in pre-puberty and puberty, after which it improved again to pre-puberty or better values at

  19. 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. PMID:21909301

  20. Study on the correlation between state of charge and coulombic efficiency for commercial lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Zheng, Yuejiu; Ouyang, Minggao; Lu, Languang; Li, Jianqiu; Zhang, Zhendong; Li, Xiangjun

    2015-09-01

    Coulombic efficiency (CE) is an important parameter for battery cells. Unfortunately, precise measurement of CE is extremely difficult, so CE is seldom focused during cell performance study. Nevertheless, correlation between stage of charge (SOC) and CE has significant impact on battery pack performance, while the influences of different correlations between SOC and CE on battery packs have never been explored as far as we know. We present a novel method which implements two series-connected cells that can determine the correlation between SOC and CE. The experimental result shows that CE is almost invariant with SOC changes for the experimental commercial LiFePO4/C cells. This paper further investigates series-connected cells with three typical correlations between SOC and CE in simulations. The simulation results indicate that cells with negative correlations between CE and SOC are preferred for series-connected battery packs, as they tend to diminish SOC difference and increase the pack capacity which can be considered as a self-balancing mechanism.