2,737 research outputs found
The Relationship of Scores on Dynamic Indicators of Basic Early Literacy Skills, Word Use Fluency to Word Knowledge and Shyness
Limited research has been conducted to determine the link between the Dynamic Indicators of Basic Early Literacy Skills (DD3ELS); Word Use Fluency, and reading ability. In addition, a link between the personality trait of shyness and lower performance on language tests has been established. The purpose of the present study was two fold. First this study aimed to determine how well the DIBELS Word Use Fluency indicator measures vocabulary knowledge. Second, the strength of the relationship between scores on the DIBELS measure and shyness was established. This helped to understand if Word Use Fluency underestimated the vocabulary knowledge of students who are shy. Participants included 35 second-grade students from upstate New York schools, rated by their teachers as shy or not shy. Each participant was evaluated with the DIBELS: Word Use Fluency and Oral Reading Fluency, Receptive One Word Picture Vocabulary Test, and the Expressive One Word Picture Vocabulary Test. A significant negative correlation existed between the shyness rating and Word Use Fluency. In addition Word Use Fluency was significantly correlated with expressive vocabulary for not shy students. A Multivariate Analysis of Variance indicated a significant difference between the performance of shy students and not shy students on Word Use Fluency, but no difference on the Expressive One Word Picture Vocabulary Test
Spin Blockade in Capacitively Coupled Quantum Dots
We present transport measurements on a lateral double dot produced by
combining local anodic oxidation and electron beam lithography. We investigate
the tunability of our device and demonstrate, that we can switch between
capacitive and tunnel coupling. In the regime of capacitive coupling we observe
the phenomenon of spin blockade in a magnetic field and analyze the influence
of capacitive interdot coupling on this effect.Comment: 4 pages, 3 figure
Combined atomic force microscope and electron-beam lithography used for the fabrication of variable-coupling quantum dots
We have combined direct nanofabrication by local anodic oxidation with
conventional electron-beam lithography to produce a parallel double quantum dot
based on a GaAs/AlGaAs heterostructure. The combination of both nanolithography
methods allows to fabricate robust in-plane gates and Cr/Au top gate electrodes
on the same device for optimal controllability. This is illustrated by the
tunability of the interdot coupling in our device. We describe our fabrication
and alignment scheme in detail and demonstrate the tunability in
low-temperature transport measurements.Comment: 4 pages, 3 figure
Sheared magnetospheric plasma flows and discrete auroral arcs: a quasi-static coupling model
We consider sheared flows in magnetospheric boundary layers of tangential discontinuity type, forming a structure that is embedded in a large-scale convergent perpendicular electric field. We construct a kinetic model that couples the magnetospheric structure with the topside ionosphere. The contribution of magnetospheric electrons and ionospheric electrons and ions is taken into account into the current-voltage relationship derived for an electric potential monotonically decreasing with the altitude. The solution of the current continuity equation gives the distribution of the ionospheric potential consistent with the given magnetospheric electric potential. The model shows that a sheared magnetospheric flow generates current sheets corresponding to upward field-aligned currents, field-aligned potential drops and narrow bands of precipitating energy, as in discrete auroral arcs. Higher velocity magnetospheric sheared flows have the tendency to produce brighter and slightly broader arcs. An increase in arc luminosity is also associated with enhancements of magnetospheric plasma density, in which case the structures are narrower. Finally, the model predicts that an increase of the electron temperature of the magnetospheric flowing plasma corresponds to slightly wider arcs but does not modify their luminosity
Kondo effect in a few-electron quantum ring
A small quantum ring with less than 10 electrons was studied by transport
spectroscopy. For strong coupling to the leads a Kondo effect is observed and
used to characterize the spin structure of the system in a wide range of
magnetic fields. At small magnetic fields Aharonov-Bohm oscillations influenced
by Coulomb interaction appear. They exhibit phase jumps by at the
Coulomb-blockade resonances. Inside Coulomb-blockade valleys the Aharonov-Bohm
oscillations can also be studied due to the finite conductance caused by the
Kondo effect. Astonishingly, the maxima of the oscillations show linear shifts
with magnetic field and gate voltage.Comment: 4 pages, 4 figure
Simulator study of flight characteristics of a large twin-fuselage cargo transport airplane during approach and landing
A six degree-of-freedom, ground-based simulator study was conducted to evaluate the low speed flight characteristics of a twin fuselage cargo transport airplane and to compare these characteristics with those of a large, single fuselage (reference) transport configuration which was similar to the Lockheed C-5C airplane. The primary piloting task was the approach and landing. The results indicated that in order to achieve "acceptable' low speed handling qualities on the twin fuselage concept, considerable stability and control augmentation was required, and although the augmented airplane could be landed safely under adverse conditions, the roll performance of the aircraft had to be improved appreciably before the handling qualities were rated as being "satisfactory.' These ground-based simulation results indicated that a value of t sub phi = 30 (time required to bank 30 deg) less than 6 sec should result in "acceptable' roll response characteristics, and when t sub phi = 30 is less than 3.8 sec, "satisfactory' roll response should be attainable on such large and unusually configured aircraft as the subject twin fuselage cargo transport concept
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