198 research outputs found
Parental ability to support their children\u27s education of mathematics
The purpose of this study is to determine the extent to which parents/guardians can adequately support the success of their children\u27s innovative mathematics curriculum. The study raises questions about the skills and knowledge parents have about today\u27s mathematical practices. Are parents informed enough to sufficiently support their children\u27s mathematical achievement? A qualitative review will take place by collecting student perception surveys, parent perception surveys, parent interviews, and a teacher journal recording home-school communication. This study is concerned with how teachers at Webster Elementary School will better be able to foster an environment where the mathematics needs of parents and children are met to further student achievement
An Algorithm for constructing Hjelmslev planes
Projective Hjelmslev planes and Affine Hjelmselv planes are generalisations
of projective planes and affine planes. We present an algorithm for
constructing a projective Hjelmslev planes and affine Hjelsmelv planes using
projective planes, affine planes and orthogonal arrays. We show that all
2-uniform projective Hjelmslev planes, and all 2-uniform affine Hjelsmelv
planes can be constructed in this way. As a corollary it is shown that all
2-uniform Affine Hjelmselv planes are sub-geometries of 2-uniform projective
Hjelmselv planes.Comment: 15 pages. Algebraic Design Theory and Hadamard matrices, 2014,
Springer Proceedings in Mathematics & Statistics 13
On the dephasing time of the chiral metal
In the low-dimensional disordered systems the dephasing time and the
inelastic scattering (out-scattering) time are in general different. We show
that in the case of the two-dimensional chiral metal which is formed at the
surface of a layered three dimensional system, which is exhibiting the integer
quantum Hall effect these two quantities are essentially the same and their
temperature-dependence is T^(-3/2). In particular we show that the results
obtained using the diagramatic technique and the phase uncertainty approach
introduced by A. Stern et al. (Phys. Rev. A 41, 3436 (1990)) for the
out-scattering and the dephasing time respectively, coincide. We furthermore
consider these quantities in the case of the three-dimensional chiral metal,
where similar conclusions are reached.Comment: 6 pages, 1 figure, europhys.st
Key action fields for nearly carbon-neutral districts: Stakeholder-specific strategies and practice
In accordance with the UN Sustainable Development Goals, many countries aim at nearly zero carbon emissions of their building sector by 2050. The research college EnEff.Buildings.2050 is a collaboration of five PhD students and their supervisors to support this goal. In this paper, five key action fields for transformation of urban districts are described, and decisive stakeholders are identified and linked to the action fields. As a case study, the urban district Mierendorff-Island in Berlin is introduced.
Three strategies to support transformation are identified: Firstly, new digital planning tools should be applied to assess and improve the energetic performance of new and existing buildings and to illustrate it to decision makers. Secondly, digital processes should be combined throughout the lifecycle of a building by building information modeling (BIM). This can ensure the energetic quality and enable cost-effective construction, servicing and monitoring. Thirdly, start-ups and contractors need support for development of new business models and technical solutions, which can e.g. enable disruptive technologies. Awareness of stakeholders on the transformational state of a district enables them to identify windows of opportunity to spring into action. Framework conditions and support measures determine if they act in favour of the transformation or not
Enhancement of de Haas-van Alphen Oscillation due to Spin in the Magnetic Breakdown System
The effects of the Zeeman term on the de Haas-van Alphen oscillation is
studied in the magnetic breakdown system. We find that the amplitude of the
oscillation with the frequencies of and are enhanced by the Zeeman term, while they are expected to be
reduced in the semiclassical theory. A possible interpretation of the
experiments in organic conductors is discussed.Comment: 4 pages,4 figures. Submitted to Journal of Physical Society of Japa
Quantization of the Hall conductivity well beyond the adiabatic limit in pulsed magnetic fields
We measure the Hall conductivity, , on a Corbino geometry sample
of a high-mobility AlGaAs/GaAs heterostructure in a pulsed magnetic field. At a
bath temperature about 80 mK, we observe well expressed plateaux in
at integer filling factors. In the pulsed magnetic field, the
Laughlin condition of the phase coherence of the electron wave functions is
strongly violated and, hence, is not crucial for quantization.Comment: 4 pages, 4 figures, submitted to PR
A new quantum fluid at high magnetic fields in the marginal charge-density-wave system -(BEDT-TTF)Hg(SCN) (where ~K and Rb)
Single crystals of the organic charge-transfer salts
-(BEDT-TTF)Hg(SCN) have been studied using Hall-potential
measurements (K) and magnetization experiments ( = K, Rb). The data show
that two types of screening currents occur within the high-field,
low-temperature CDW phases of these salts in response to time-dependent
magnetic fields. The first, which gives rise to the induced Hall potential, is
a free current (), present at the surface of the sample.
The time constant for the decay of these currents is much longer than that
expected from the sample resistivity. The second component of the current
appears to be magnetic (), in that it is a microscopic,
quasi-orbital effect; it is evenly distributed within the bulk of the sample
upon saturation. To explain these data, we propose a simple model invoking a
new type of quantum fluid comprising a CDW coexisting with a two-dimensional
Fermi-surface pocket which describes the two types of current. The model and
data are able to account for the body of previous experimental data which had
generated apparently contradictory interpretations in terms of the quantum Hall
effect or superconductivity.Comment: 13 pages, 11 figure
Critical State Behaviour in a Low Dimensional Metal Induced by Strong Magnetic Fields
We present the results of magnetotransport and magnetic torque measurements
on the alpha-(BEDT-TTF)2KHg(SCN)4 charge-transfer salt within the high magnetic
field phase, in magnetic fields extending to 33 T and temperatures as low as 27
mK. While the high magnetic field phase (at fields greater than ~ 23 T) is
expected, on theoretical grounds, to be either a modulated charge-density wave
phase or a charge/spin-density wave hybrid, the resistivity undergoes a
dramatic drop below ~ 3 K within the high magnetic field phase, falling in an
approximately exponential fashion at low temperatures, while the magnetic
torque exhibits pronounced hysteresis effects. This hysteresis, which occurs
over a broad range of fields, is both strongly temperature-dependent and has
several of the behavioural characteristics predicted by critical-state models
used to describe the pinning of vortices in type II superconductors in strong
magnetic fields. Thus, rather than exhibiting the usual behaviour expected for
a density wave ground state, both the transport and the magnetic properties of
alpha-(BEDT-TTF)2KHg(SCN)4, at high magnetic fields, closely resembles those of
a type II superconductor
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