907 research outputs found
High Stakes Assessment and Testing Disconnect: Examining Student Performance on Grades 3—6 Common Core ELA and Math Assessments and Performance on English and Algebra Regents Exams in High School
New York State public school students in grades 3–8 are required to take the Common Core assessments, now based on Next Generation Learning Standards, in English language arts and mathematics. Students are also required to take English and Algebra Regents exams in high school. Elementary students who often perform on-grade level in the classroom frequently struggle on the spring Common Core assessments, yet successfully graduate from high school. This longitudinal study aimed to determine if the 3–6 assessments at the elementary level are related and predictive of how students would perform on high school English and Algebra Regents exams a decade later. This research also addresses how students designated as economically disadvantaged and students having a disability requiring an Individualized Educational Plan would perform on both state assessments given their identification by the school district.
Descriptive and inferential statistics were used to track 120 grade 3 students through their high school graduation by comparing their Common Core rubric scores in elementary school to their English and Algebra Regents exams percentages. Research findings indicate that regardless of how students performed on Common Core assessments English language arts in elementary school, students easily passed their high school English Regents exams. However, elementary students who struggled with lower rubric scores in mathematics passed their Algebra Regents exams, but at lower proficiency levels. In addition, students designated as economically disadvantaged were able to pass their high school Regents exams at passage rates equal to their peers, indicating this designation of poverty had no bearing on a student’s performance. However, students identified by the school district as having a disability requiring an Individualized Educational Plan did struggle on both their elementary Common Core assessments and high school Regents exams.
This longitudinal study adds to this under researched topic of comparing elementary students’ testing performance on New York State assessments to their high school performance levels on English and Algebra Regents exams
Dynamical Instability in a Trimeric Chain of Interacting Bose-Einstein Condensates
We analyze thoroughly the mean-field dynamics of a linear chain of three
coupled Bose-Einstein condensates, where both the tunneling and the
central-well relative depth are adjustable parameters. Owing to its
nonintegrability, entailing a complex dynamics with chaos occurrence, this
system is a paradigm for longer arrays whose simplicity still allows a thorough
analytical study.We identify the set of dynamics fixed points, along with the
associated proper modes, and establish their stability character depending on
the significant parameters. As an example of the remarkable operational value
of our analysis, we point out some macroscopic effects that seem viable to
experiments.Comment: 5 pages, 3 figure
Microwave-dressed state-selective potentials for atom interferometry
International audienceWe propose a novel and robust technique to realize a beam splitter for trapped Bose–Einstein condensates (BECs). The scheme relies on the possibility of producing different potentials simultaneously for two internal atomic states. The atoms are coherently transferred, via a Rabi coupling between the two long-lived internal states, from a single well potential to a double-well. We present numerical simulations supporting our proposal and confirming excellent efficiency and fidelity of the transfer process with realistic numbers for a BEC of 87 Rb. We discuss the experimental implementation by suggesting state-selective microwave (MW) potentials as an ideal tool to be exploited for magnetically trapped atoms. The working principles of this technique are tested on our atom chip device which features an integrated coplanar MW guide. In particular, the first realization of a double-well potential by using a MW dressing field is reported. Experimental results are presented together with numerical simulations, showing good agreement. Simultaneous and independent control on the external potentials is also demonstrated in the two Rubidium clock states. The transfer between the two states, featuring respectively a single and a double-well, is characterized and it is used to measure the energy spectrum of the atoms in the double-well. Our results show that the spatial overlap between the two states is crucial to ensure the functioning of the beamsplitter. Even though this condition could not be achieved in our current setup, the proposed technique can be realized with current state-of-the-art devices being particularly well suited for atom chip experiments. We anticipate applications in quantum enhanced interferometry
Dynamically controlled toroidal and ring-shaped magnetic traps
We present traps with toroidal and ring-shaped topologies, based on
adiabatic potentials for radio-frequency dressed Zeeman states in a ring-shaped
magnetic quadrupole field. Simple adjustment of the radio-frequency fields
provides versatile possibilities for dynamical parameter tuning, topology
change, and controlled potential perturbation. We show how to induce toroidal
and poloidal rotations, and demonstrate the feasibility of preparing degenerate
quantum gases with reduced dimensionality and periodic boundary conditions. The
great level of dynamical and even state dependent control is useful for atom
interferometry.Comment: 6 pages, 4 figures. Paragraphs on gravity compensation and expected
trap lifetimes adde
Quantitative study of quasi-one-dimensional Bose gas experiments via the stochastic Gross-Pitaevskii equation
The stochastic Gross-Pitaevskii equation is shown to be an excellent model
for quasi-one-dimensional Bose gas experiments, accurately reproducing the in
situ density profiles recently obtained in the experiments of Trebbia et al.
[Phys. Rev. Lett. 97, 250403 (2006)] and van Amerongen et al. [Phys. Rev. Lett.
100, 090402 (2008)], and the density fluctuation data reported by Armijo et al.
[Phys. Rev. Lett. 105, 230402 (2010)]. To facilitate such agreement, we propose
and implement a quasi-one-dimensional stochastic equation for the low-energy,
axial modes, while atoms in excited transverse modes are treated as independent
ideal Bose gases.Comment: 10 pages, 5 figures; updated figures with experimental dat
The kinetic description of vacuum particle creation in the oscillator representation
The oscillator representation is used for the non-perturbative description of
vacuum particle creation in a strong time-dependent electric field in the
framework of scalar QED. It is shown that the method can be more effective for
the derivation of the quantum kinetic equation (KE) in comparison with the
Bogoliubov method of time-dependent canonical transformations. This KE is used
for the investigation of vacuum creation in periodical linear and circular
polarized electric fields and also in the case of the presence of a constant
magnetic field, including the back reaction problem. In particular, these
examples are applied for a model illustration of some features of vacuum
creation of electron-positron plasma within the planned experiments on the
X-ray free electron lasers.Comment: 17 pages, 3 figures, v2: a reference added; some changes in tex
Cold atoms in videotape micro-traps
We describe an array of microscopic atom traps formed by a pattern of
magnetisation on a piece of videotape. We describe the way in which cold atoms
are loaded into one of these micro-traps and how the trapped atom cloud is used
to explore the properties of the trap. Evaporative cooling in the micro-trap
down to a temperature of 1 microkelvin allows us to probe the smoothness of the
trapping potential and reveals some inhomogeneity produced by the magnetic
film. We discuss future prospects for atom chips based on microscopic
permanent-magnet structures.Comment: Submitted for EPJD topical issue "Atom chips: manipulating atoms and
molecules with microfabricated structures
Nanoscale atomic waveguides with suspended carbon nanotubes
We propose an experimentally viable setup for the realization of
one-dimensional ultracold atom gases in a nanoscale magnetic waveguide formed
by single doubly-clamped suspended carbon nanotubes. We show that all common
decoherence and atom loss mechanisms are small guaranteeing a stable operation
of the trap. Since the extremely large current densities in carbon nanotubes
are spatially homogeneous, our proposed architecture allows to overcome the
problem of fragmentation of the atom cloud. Adding a second nanowire allows to
create a double-well potential with a moderate tunneling barrier which is
desired for tunneling and interference experiments with the advantage of
tunneling distances being in the nanometer regime.Comment: Replaced with the published version, 7 pages, 3 figure
Novel Ferromagnetic Atom Waveguide with in situ loading
Magneto-optic and magnetostatic trapping is realized near a surface using
current carrying coils wrapped around magnetizable cores. A cloud of 10^7
Cesium atoms is created with currents less than 50 mA. Ramping up the current
while maintaining optical dissipation leads to tightly confined atom clouds
with an aspect ratio of 1:1000. We study the 3D character of the magnetic
potential and characterize atom number and density as a function of the applied
current. The field gradient in the transverse dimension has been varied from <
10 G/cm to > 1 kG/cm. By loading and cooling atoms in-situ, we have eliminated
the problem of coupling from a MOT into a smaller phase space.Comment: 4 pages, 4 figure
Seeking better times: atomic clocks in the generalized Tonks-Girardeau regime
This article is based on the talk with the same title at the Blaubeuren
meeting. First we discuss briefly the importance of time and time keeping,
explaining the basic functioning of clocks in general and atomic clocks in
particular, which rely on Ramsey interferometry. The usefulness of cold atoms
is discussed as well as their limits in Bose-Einstein condensates. An
alternative that we study is a different cold-atom regime: the Tonks-Girardeau
(TG) gas of tightly confined and strongly interacting bosons. The TG gas is
reviewed and then generalized for two-level atoms. Finally, we explore the
combination of Ramsey interferometry and TG gases.Comment: Revised manuscript, 8 pages, 8 figures, proceedings of the 395th
WE-Heraeus Seminar on "Time Dependent Phenomena in Quantum Mechanics ",
Blaubeuren, Germany, September 200
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