1,948 research outputs found
Literacy Instruction and the Learning Disabled High School Student : Ideas and Applications for a Mindful Classroom
This thesis suggests that the emergent field of mindfulness and contemplative pedagogy can be a uniquely effective tool for use in the English classroom for learning disabled (LD) high school students. By first exploring definitions of difference and initiating a conversation about how we, as a society, conceptualize difference and how we provide literacy instruction for students who learn differently, this thesis advocates for a more complex and meaningful understanding of the difficult issues surrounding teaching literature and writing to LD high school students. The discussion then introduces some of the central tenets of mindfulness and contemplative practice and explores, first, some of its historical underpinnings and then, secondly, looks to some of its current applications in educational settings. An argument is made that the specific benefits of this type of approach—improved attention, awareness and empathy—are exactly the issues that seem to be most problematic for LD high school students. Because of this, mindulness and contemplative pedagogy has unique potential as an effective strategy with LD students. Finally, this thesis explores how the high school English classroom, in its attention to both literature and student writing is an ideal site for such an endeavor. By teaching LD students to use reflection and other contemplative strategies while reading literary texts and doing writing assignments, educators can help students make meaningful connections between themselves and what they learn. Ultimately, this kind of attention and awareness fosters confidence and curiosity in students and helps them to engage more meaningfully not only with what they read and write, but also with the world they live in
Physical Mechanism of the d->d+is Transition
We discuss the basic physical mechanism of the d->d+is transition, which is
the currently accepted explanation for the results of tunneling experiments
into planes. Using the first-order perturbation theory, we show that the
zero-bias states drive the transition. We present various order-of-magnitude
estimates and consistency checks that support this picture.Comment: 7 pages, 2 figure
Different regimes of Forster energy transfer between an epitaxial quantum well and a proximal monolayer of semiconductor nanocrystals
We calculate the rate of non-radiative, Forster-type energy transfer (ET)
from an excited epitaxial quantum well (QW) to a proximal monolayer of
semiconductor nanocrystal quantum dots (QDs). Different electron-hole
configurations in the QW are considered as a function of temperature and
excited electron-hole density. A comparison of the theoretically determined ET
rate and QW radiative recombination rate shows that, depending on the specific
conditions, the ET rate is comparable to or even greater than the radiative
recombination rate. Such efficient Forster ET is promising for the
implementation of ET-pumped, nanocrystal QD-based light emitting devices.Comment: 14 pages, 4 figure
Spin noise of itinerant fermions
We develop a theory of spin noise spectroscopy of itinerant, noninteracting,
spin-carrying fermions in different regimes of temperature and disorder. We use
kinetic equations for the density matrix in spin variables. We find a general
result with a clear physical interpretation, and discuss its dependence on
temperature, the size of the system, and applied magnetic field. We consider
two classes of experimental probes: 1. electron-spin-resonance (ESR)-type
measurements, in which the probe response to a uniform magnetization increases
linearly with the volume sampled, and 2. optical Kerr/Faraday rotation-type
measurements, in which the probe response to a uniform magnetization increases
linearly with the length of the light propagation in the sample, but is
independent of the cross section of the light beam. Our theory provides a
framework for interpreting recent experiments on atomic gases and conduction
electrons in semiconductors and provides a baseline for identifying the effects
of interactions on spin noise spectroscopy
Positive and negative streamers in ambient air: measuring diameter, velocity and dissipated energy
Positive and negative streamers are studied in ambient air at 1 bar; they
emerge from a needle electrode placed 40 mm above a planar electrode. The
amplitudes of the applied voltage pulses range from 5 to 96 kV; most pulses
have rise times of 30 ns or shorter. Diameters, velocities and energies of the
streamers are measured. Two regimes are identified; a low voltage regime where
only positive streamers appear and a high voltage regime where both positive
and negative streamers exist. Below 5 kV, no streamers emerge. In the range
from 5 to 40 kV, positive streamers form, while the negative discharges only
form a glowing cloud at the electrode tip, but no streamers. For 5 to 20 kV,
diameters and velocities of the positive streamers have the minimal values of
d=0.2 mm and v \approx 10^5 m/s. For 20 to 40 kV, their diameters increase by a
factor 6 while the voltage increases only by a factor 2. Above the transition
value of 40 kV, streamers of both polarities form; they strongly resemble each
other, though the positive ones propagate further; their diameters continue to
increase with applied voltage. For 96 kV, positive streamers attain diameters
of 3 mm and velocities of 4*10^6 m/s, negative streamers are about 20 % slower
and thinner. An empirical fit formula for the relation between velocity v and
diameter d is v=0.5 d^2/(mm ns) for both polarities. Streamers of both
polarities dissipate energies of the order of several mJ per streamer while
crossing the gap.Comment: 20 pages, 9 figures, accepted for J. Phys.
Nuclear Cryogenic Propulsion Stage Conceptual Design and Mission Analysis
The Nuclear Cryogenic Propulsion Stage (NCPS) is an in-space transportation vehicle, comprised of three main elements, designed to support a long-stay human Mars mission architecture beginning in 2035. The stage conceptual design and the mission analysis discussed here support the current nuclear thermal propulsion going on within partnership activity of NASA and the Department of Energy (DOE). The transportation system consists of three elements: 1) the Core Stage, 2) the In-line Tank, and 3) the Drop Tank. The driving mission case is the piloted flight to Mars in 2037 and will be the main point design shown and discussed. The corresponding Space Launch System (SLS) launch vehicle (LV) is also presented due to it being a very critical aspect of the NCPS Human Mars Mission architecture due to the strong relationship between LV lift capability and LV volume capacity
Interplanetary Mission Design Handbook: Earth-to-Mars Mission Opportunities and Mars-to-Earth Return Opportunities 2009-2024
This paper provides information for trajectory designers and mission planners to determine Earth-Mars and Mars-Earth mission opportunities for the years 2009-2024. These studies were performed in support of a human Mars mission scenario that will consist of two cargo launches followed by a piloted mission during the next opportunity approximately 2 years later. "Porkchop" plots defining all of these mission opportunities are provided which include departure energy, departure excess speed, departure declination arrival excess speed, and arrival declinations for the mission space surrounding each opportunity. These plots are intended to be directly applicable for the human Mars mission scenario described briefly herein. In addition, specific trajectories and several alternate trajectories are recommended for each cargo and piloted opportunity. Finally, additional studies were performed to evaluate the effect of various thrust-to-weight ratios on gravity losses and total time-of-flight tradeoff, and the resultant propellant savings and are briefly summarized
Advanced Lithography Simulation Tools for Development and Analysis of Wide-Field High Numerical Aperture Projection Optical Systems
Industrial demands for integrated circuits of higher speed and complexity have required the development of advanced lithographic exposure tools capable of sub-half micron resolution over increasingly larger fields. To this end, i-line and deep-uv tools employing Variable, high numerical aperture (NA) objectives are being aggressively developed. The design and manufacture of these advanced optical systems has also grown in complexity, since tighter tolerances on resolution and image placement must be maintained over the larger lens field. At the same time, usable focus and exposure latitude must be retained. The influence of lens aberrations on image formation under different illumination conditions, along with their non-intuitive nature has required the development of simulation tools that allow both the designer and the user of these systems to better understand their implications. These tools can be used to investigate and optimize the lithography process, including the effects of emerging technologies such as phase-shift masking, oblique illumination and frequency plane filtering./super 1,2,3/ This paper presents a method for determining the effects and interactions of various aberrations and illumination conditions using a statistically designed experhnent./super 4/ Fundamental differences in the way the aerial image is formed when varying the pupil energy distribution in the presence of aberrations are presented, as are examples of some of the more interesting effects
Strain control of superlattice implies weak charge-lattice coupling in LaCaMnO
We have recently argued that manganites do not possess stripes of charge
order, implying that the electron-lattice coupling is weak [Phys Rev Lett
\textbf{94} (2005) 097202]. Here we independently argue the same conclusion
based on transmission electron microscopy measurements of a nanopatterned
epitaxial film of LaCaMnO. In strain relaxed regions, the
superlattice period is modified by 2-3% with respect to the parent lattice,
suggesting that the two are not strongly tied.Comment: 4 pages, 4 figures It is now explained why the work provides evidence
to support weak-coupling, and rule out charge orde
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