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

A new quantum fluid at high magnetic fields in the marginal charge-density-wave system α\alpha-(BEDT-TTF)2M_2MHg(SCN)4_4 (where M=M=~K and Rb)

Single crystals of the organic charge-transfer salts $\alpha$-(BEDT-TTF)$_2M$Hg(SCN)$_4$ have been studied using Hall-potential measurements ($M=$K) and magnetization experiments ($M$ = K, Rb). The data show that two types of screening currents occur within the high-field, low-temperature CDW$_x$ 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 (${\bf j}_{\rm free}$), 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 (${\bf j}_{\rm mag}$), 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

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 $f_{\beta} + f_{\alpha}$ and $f_{\beta} + 2f_{\alpha}$ 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, $\sigma_{xy}$, 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 $\sigma_{xy}$ 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 $\sigma_{xy}$ quantization.Comment: 4 pages, 4 figures, submitted to PR

The transverse magnetoresistance of the two-dimensional chiral metal

We consider the two-dimensional chiral metal, which exists at the surface of a layered, three-dimensional sample exhibiting the integer quantum Hall effect. We calculate its magnetoresistance in response to a component of magnetic field perpendicular to the sample surface, in the low temperature, but macroscopic, regime where inelastic scattering may be neglected. The magnetoresistance is positive, following a Drude form with a field scale, $B_0=\Phi_0/al_{\text{el}}$, given by the transverse field strength at which one quantum of flux, $\Phi_0$, passes through a rectangle with sides set by the layer-spacing, $a$, and the elastic mean free path, $l_{\text{el}}$. Experimental measurement of this magnetoresistance may therefore provide a direct determination of the elastic mean free path in the chiral metal.Comment: submitted to Phys Rev