283 research outputs found
The impact of block scheduling on special education student learning in high school mathematics
This study evaluated block scheduling and its impact on a special education math program at Delsea Regional High School. It was determined that the end of the marking period test scores were slightly higher for those students in a block schedule than for those students in a traditional setting.
It was also determined that most teachers surveyed do not feel that block scheduling is beneficial for certain special needs students because extended time on task sometimes leads to more discipline problems, especially for those students suffering from attention deficit disorder
Multispecies Extensions to a Nonequilibrium Length-Based Mortality Estimator
Recent advances in methodology allow the history of the total mortality rate experienced by a population to be estimated from periodic (e.g., annual) observations on themean length of the population. This approach is generalized to allow data on several species that are caught together to be analyzed simultaneously based on the theory that changes in fishing effort are likely to affect several species; thus, the estimation of times when the mortality rate changes for one species borrows strength from data on other, concurrently caught species. Information theory can be used to select among models describing the degree of synchrony (if any) in mortality changes for a suite of species. This approach is illustrated using data on Puerto Rican handline fishery catches of three snapper species: Silk Snapper Lutjanus vivanus, Blackfin Snapper L. buccanella, and Vermilion Snapper Rhomboplites aurorubens. We identified the best model as the one that provided for simultaneous decreases in mortality rate around the year 1997 and for separate, species-specific magnitudes of change in total mortality. The simultaneous estimation of parameters for multiple species can provide for more credibility in the inferred mortality trends than is possible with independent estimation for each species
Linear Temperature Variation of the Penetration Depth in YBCO Thin Films
We have measured the penetration depth on thin films from transmission at 120, 330 and 510~GHz,
between 5 and 50~K. Our data yield simultaneously the absolute value and the
temperature dependence of . In high quality films
exhibits the same linear temperature dependence as single crystals, showing its
intrinsic nature, and . In a lower quality one, the
more usual dependence is found, and . This
suggests that the variation is of extrinsic origin. Our results put the
-wave like interpretation in a much better position.Comment: 12 pages, revtex, 4 uuencoded figure
Penetration Depth and Anisotropy in MgB2
The penetration depth lambda of MgB2 was deduced from both the ac
susceptibility chi and the magnetization M(H) of sorted powders. The good
agreement between the two sets of data without geometric correction for the
grain orientation suggests that MgB2 is an isotropic superconductor.Comment: 9 pages, 5 figures; submitted to Physical Review B (February 28,
2001; revised June 28, 2001); reference list update
GENERAL COMBINING ABILITY EFFECTS FOR REPRODUCTIVE HEAT TOLERANCE IN SNAP BEAN
GENERAL COMBINING ABILITY EFFECTS FOR REPRODUCTIVE HEAT TOLERANCE IN SNAP BEA
Penetration Depth Measurements in MgB_2: Evidence for Unconventional Superconductivity
We have measured the magnetic penetration depth of the recently discovered
binary superconductor MgB_2 using muon spin rotation and low field
-susceptibility. From the damping of the muon precession signal we find the
penetration depth at zero temperature is about 85nm. The low temperature
penetration depth shows a quadratic temperature dependence, indicating the
presence of nodes in the superconducting energy gap.Comment: 4 pages 3 figure
Systematic behaviour of the in-plane penetration depth in d-wave cuprates
We report the temperature T and oxygen concentration dependences of the
penetration depth of grain-aligned YBa_2Cu_3O_{7-\delta} with \delta= 0.0, 0.3
and 0.43. The values of the in-plane \lambda_{ab}(0) and out-of-plane
\lambda_{c}(0) penetration depths, the low temperature linear term in
\lambda_{ab}(T), and the ratio \lambda_{c}(0) /\lambda_{ab}(T) were found to
increase with increasing . The systematic changes of the linear term in
\lambda_{ab}(T) with T_c found here and in recent work on HgBa_2Ca_{n-1}
Cu_nO_{2n+2+\delta} (n = 1 and 3) are discussed.Comment: 4 pages, 4 figure
c-Axis Superfluid Response and Pseudogap in High-Tc Superconductors
To gain insight into the out-of-plane electrodynamics of high-
superconduct ors we have measured the absolute values and temperature
dependence of the c-a xis magnetic penetration depth for two
typical single layer high - cuprates, LaSrCuO and
HgBaCuO as a function o f doping. A distinct change in the
behaviour of is observed near 0. 20 holes/Cu, which is related to
the opening of the normal state pseudogap. The variation of with
doping is qualitatively similar to that of the in -plane component, , which suggests that the c-axis superfluid r esponse is mainly governed
by the superconducting condensation energy. The stron g doping dependence of
for p<0.20 provides an explanation for the discrepancies in the
literature.Comment: 4 pages, 2 figure
Pressure effect on the in-plane magnetic penetration depth in YBa_2Cu_4O_8
We report a study of the pressure effect (PE) on the in-plane magnetic field
penetration depth lambda_{ab} in YBa_2Cu_4O_8 by means of Meissner fraction
measurements. A pronounced PE on lambda_{ab}^{-2}(0) was observed with a
maximum relative shift of \Delta\lambda^{-2}_{ab}/\lambda^{-2}_{ab}= 44(3)% at
a pressure of 10.2 kbar. It arises from the pressure dependence of the
effective in-plane charge carrier mass and pressure induced charge carrier
transfer from the CuO chains to the superconducting CuO_2 planes. The present
results imply that the charge carriers in YBa_2Cu_4O_8 are coupled to the
lattice.Comment: 4pages 3 figure
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