4,940 research outputs found
Invented Spelling : A Study in its Usage to Impact Literacy
Forty-seven first grade students from an urban school district participated in a study on the use of invented spelling. The program was designed to determine if invented spelling was effective in teaching a list of grade level spelling words and whether it would impact their reading achievement. Eighteen students served as the control group.
Materials included the California Achievement Test Level 10 Form E for the pretest in reading and Level 11 for the posttest. A Core Competency Spelling List for grade one was used in measuring spelling progress.
The study took place for one school year . Twenty- nine students in the treatment group were given daily writing assignments allowing them to use invented spelling. A weekly spelling test included those words from the list that were emphasized in writing and reading tasks during the week. The control group was given formal spelling instruction for five words each week, also from the grade list, but chosen at random by the researcher. The Durrell Pre-Reading Phonics Ability Test and the Wepman Auditory Discrimination Test was given to the control group.
Results from a series of t tests indicated that giving children the opportunity to use invented spelling had a positive effect on spelling and reading achievement
Sub-nanometer free electrons with topological charge
The holographic mask technique is used to create freely moving electrons with
quantized angular momentum. With electron optical elements they can be focused
to vortices with diameters below the nanometer range. The understanding of
these vortex beams is important for many applications. Here we present a theory
of focused free electron vortices. The agreement with experimental data is
excellent. As an immediate application, fundamental experimental parameters
like spherical aberration and partial coherence are determined.Comment: 4 pages, 5 figure
Systematics in the Pb^(208)-Th^(232), Pb^(207)-U^(235), and Pb^(206)-U^(238) Systems
In a study of cogenetic zircons it was found that the measured Pb^(208)/Th^(232) and Pb^(207)/U^(235) ratios formed a linear array in the corresponding coupled Pb-U-Th evolution diagram, which has an upper intersection on the concordia curve at the same time point as that determined by the Pb^(206)/U^(238), Pb^(207)/U^(235) array. Although the U-Pb data lie in the accessible region for nonfractionating daughter loss, the Th-Pb results lie outside the corresponding region. The zircon concentrates analyzed were shown to be multiphase assemblages with variable U and Th contents and variable Th/U ratios, even within single crystals. The zircons contain local domains of high radioactivity which appear to be highly discordant. A relationship between discordance and the average concentration of U and Th in a sample is given. The degree of discordance increases with the concentration of U and Th and with the increasing Th/U ratio, causing preferential loss of Pb^(208) and the departure from the region accessible to a single phase without fractionation. The theoretical aspects of the (equation image) diagram from the viewpoint of single-phase and multiphase assemblages are discussed, and it is shown that the variability of the Th/U ratio is of fundamental importance in understanding the evolution of the Th-U-Pb system. The existence of these systematics in nature may provide an additional independent dating system and a further means of studying transport from natural systems
One dimensional chain of quantum molecule motors as a mathematical physics model for muscle fibre
A quantum chain model of many molecule motors is proposed as a mathematical
physics theory on the microscopic modeling of classical force-velocity relation
and tension transients of muscle fibre. We proposed quantum many-particle
Hamiltonian to predict the force-velocity relation for the slow release of
muscle fibre which has no empirical relation yet, it is much more complicate
than hyperbolic relation. Using the same Hamiltonian, we predicted the
mathematical force-velocity relation when the muscle is stimulated by
alternative electric current. The discrepancy between input electric frequency
and the muscle oscillation frequency has a physical understanding by Doppler
effect in this quantum chain model. Further more, we apply quantum physics
phenomena to explore the tension time course of cardiac muscle and insect
flight muscle. Most of the experimental tension transients curves found their
correspondence in the theoretical output of quantum two-level and three-level
model. Mathematically modeling electric stimulus as photons exciting a quantum
three-level particle reproduced most tension transient curves of water bug
Lethocerus Maximus.Comment: 16 pages, 12 figures, Arguments are adde
Oxygen flux in the solar wind: Ulysses observations
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94605/1/grl27577.pd
Variations in solar wind fractionation as seen by ACE/SWICS over a solar cycle and the implications for Genesis Mission results
We use ACE/SWICS elemental composition data to compare the variations in
solar wind fractionation as measured by SWICS during the last solar maximum
(1999-2001), the solar minimum (2006-2009) and the period in which the Genesis
spacecraft was collecting solar wind (late 2001 - early 2004). We differentiate
our analysis in terms of solar wind regimes (i.e. originating from interstream
or coronal hole flows, or coronal mass ejecta). Abundances are normalized to
the low-FIP ion magnesium to uncover correlations that are not apparent when
normalizing to high-FIP ions. We find that relative to magnesium, the other
low-FIP elements are measurably fractionated, but the degree of fractionation
does not vary significantly over the solar cycle. For the high-FIP ions,
variation in fractionation over the solar cycle is significant: greatest for
Ne/Mg and C/Mg, less so for O/Mg, and the least for He/Mg. When abundance
ratios are examined as a function of solar wind speed, we find a strong
correlation, with the remarkable observation that the degree of fractionation
follows a mass-dependent trend. We discuss the implications for correcting the
Genesis sample return results to photospheric abundances.Comment: Accepted for publication in Ap
- …