90 research outputs found

    Transition Class: A Bridge from Early Intervention to Early Childhood Special Education

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    Transitions are widely acknowledged to present challenges for young children with special needs. In the US system, the transition from early intervention (EI; services for children aged 0–3) to early childhood special education services (ECSE; services for preschool children) is a process known to cause uncertainty and anxiety for families. This paper describes a transition class offered by a midwestern US EI agency; children receiving EI services are eligible to participate beginning at age 2;6. Agency personnel chart the children’s progress each week. For this study, researchers reviewed de-identified weekly progress reports for the 40 transition class participants who attended at least 6 class sessions. Class participants demonstrated highly significant changes across time in their tolerance for separation from parents/caregivers and their participation in structured class activities. These preliminary findings suggest that a structured class with familiar service providers may support young children in acquiring skills they will need for a successful transition to ECSE

    Precision Measurement of PArity Violation in Polarized Cold Neutron Capture on the Proton: the NPDGamma Experiment

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    The NPDGamma experiment at the Los Alamos Neutron Science Center (LANSCE) is dedicated to measure with high precision the parity violating asymmetry in the γ\gamma emission after capture of spin polarized cold neutrons in para-hydrogen. The measurement will determine unambiguously the weak pion-nucleon-nucleon (πNN\pi NN) coupling constant {\it fπ1^1_{\pi}}Comment: Proceedings of the PANIC'05 Conference, Santa Fe, NM, USA, October 24-28, 2005, 3 pages, 2 figure

    High-Efficiency Resonant RF Spin Rotator with Broad Phase Space Acceptance for Pulsed Polarized Cold Neutron Beams

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    We have developed a radio-frequency resonant spin rotator to reverse the neutron polarization in a 9.5 cm x 9.5 cm pulsed cold neutron beam with high efficiency over a broad cold neutron energy range. The effect of the spin reversal by the rotator on the neutron beam phase space is compared qualitatively to RF neutron spin flippers based on adiabatic fast passage. The spin rotator does not change the kinetic energy of the neutrons and leaves the neutron beam phase space unchanged to high precision. We discuss the design of the spin rotator and describe two types of transmission-based neutron spin-flip efficiency measurements where the neutron beam was both polarized and analyzed by optically-polarized 3He neutron spin filters. The efficiency of the spin rotator was measured to be 98.0+/-0.8% on resonance for neutron energies from 3.3 to 18.4 meV over the full phase space of the beam. As an example of the application of this device to an experiment we describe the integration of the RF spin rotator into an apparatus to search for the small parity-violating asymmetry A_gamma in polarized cold neutron capture on para-hydrogen by the NPDGamma collaboration at LANSCE

    Upper Bounds on Parity Violating Gamma-Ray Asymmetries in Compound Nuclei from Polarized Cold Neutron Capture

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    Parity-odd asymmetries in the electromagnetic decays of compound nuclei can sometimes be amplified above values expected from simple dimensional estimates by the complexity of compound nuclear states. In this work we use a statistical approach to estimate the root mean square (RMS) of the distribution of expected parity-odd correlations snkγ\vec{s_{n}} \cdot \vec{k_{\gamma}}, where sn\vec {s_{n}} is the neutron spin and kγ\vec{k_{\gamma}} is the momentum of the gamma, in the integrated gamma spectrum from the capture of cold polarized neutrons on Al, Cu, and In and we present measurements of the asymmetries in these and other nuclei. Based on our calculations, large enhancements of asymmetries were not predicted for the studied nuclei and the statistical estimates are consistent with our measured upper bounds on the asymmetries

    Q

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    The Qweak experiment, which took data at Jefferson Lab in the period 2010 - 2012, will precisely determine the weak charge of the proton by measuring the parity-violating asymmetry in elastic e-p scattering at 1.1 GeV using a longitudinally polarized electron beam and a liquid hydrogen target at a low momentum transfer of Q2 = 0.025 (GeV/c)2. The weak charge of the proton is predicted by the Standard Model and any significant deviation would indicate physics beyond the Standard Model. The technical challenges and experimental apparatus for measuring the weak charge of the proton will be discussed, as well as the method of extracting the weak charge of the proton. The results from a small subset of the data, that has been published, will also be presented. Furthermore an update will be given of the current status of the data analysis
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