On a generalization of the seating couples problem

We prove a conjecture of Adamaszek generalizing the seating couples problem to the case of $2n$ seats. Concretely, we prove that given a positive integer $n$ and $d_1,\ldots,d_n\in(\mathbb{Z}/2n)^*$ we can partition $\mathbb{Z}/2n$ into $n$ pairs with differences $d_1,\ldots,d_n$.Comment: 3 page

Heegner points on Cartan non-split curves

Let $E$ be an elliptic curve of conductor $N$, and let $K$ be an imaginary quadratic field such that the root number of $E/K$ is $-1$. Let $O$ be an order in $K$ and assume that there exists an odd prime $p$, such that $p^2 \mid\mid N$, and $p$ is inert in $O$. Although there are no Heegner points on $X_0(N)$ attached to $O$, in this article we construct such points on Cartan non-split curves. In order to do that we give a method to compute Fourier expansions for forms in Cartan non-split curves, and prove that the constructed points form a Heegner system as in the classical case.Comment: 25 pages, revised versio

Local Tunneling Study of Three-Dimensional Order Parameter in the π\pi-band of Al-doped MgB2_2 Single Crystals

We have performed local tunneling spectroscopy on high quality Mg$_{1-x}$Al$_x$B$_2$ single crystals by means of Variable Temperature Scanning Tunneling Spectroscopy (STS) in magnetic field up to 3 Tesla. Single gap conductance spectra due to c-axis tunneling were extensively measured, probing different amplitudes of the three-dimensional $\Delta_\pi$ as a function of Al content. Temperature and magnetic field dependences of the conductance spectra were studied in S-I-N configuration: the effect of the doping resulted in a monotonous reduction of the locally measured $T_C$ down to 24K for x=0.2. On the other hand, we have found that the gap amplitude shows a maximum value $\Delta_\pi= 2.3$ meV for x=0.1, while the $\Delta_\pi / T_C$ ratio increases monotonously with doping. The locally measured upper critical field was found to be strongly related to the gap amplitude, showing the maximum value $H_{c2}\simeq3T$ for x=0.1 substituted samples. For this Al concentration the data revealed some spatial inhomogeneity in the distribution of $\Delta_\pi$ on nanometer scale.Comment: 4 pages, 3 figure

Time-Series Evidence of the Effect of the Minimum Wage on Youth Employment and Unemployment

While previous time series studies have quite consistently found that the minimum wage reduces teenage employment, the extent of this reduction is much less certain. Moreover, because few previous studies report results of more than one specification, the causes of differences in estimated impacts are not well understood. Less consensus is evident on the effect of the minimum wage on teenage unemployment, or its relative impact on black and white teenagers. The purpose of this paper is both to update earlier work and to analyze the sensitivity of estimated minimum wage effects to alternative specification choices. In addition to providing estimates of the effect of minimum wage increases on aggregate employment and unemployment rates of teenagers, we explore several related issues: the relative importance of changing the level and coverage of the minimum wage; the timing of responses to a change in the minimum; effects on part-time and full-time work; effects on young adults (age 20-24).

Ethical Concerns of Heroism Training

Heroism training programs originated in the mid-2000s with the goal to “Train everyday heroes” (Heroic Imagination Project, 2017). Most participants of these programs are students between the ages of 10 and 20. Anecdotal and empirical evidence suggests that these programs may create more courageous and prosocial people (Heiner, 2018; Kohen & Sólo, 2019), however there is very little discussion in the emerging academic field of heroism science about the potential ethical concerns of training minors to be heroes (Beggan, 2019; Franco & Zimbardo, 2016; Franco et al., 2017). With the growth of heroism science scholarship, it would be wise to examine and offer best practices for the ethical training of heroism with minors. Heroic action is inherently risky, and while training programs currently discuss mortality and risk assessment, minors have not developed the neural or cognitive capacity to assess risks as adults can. Furthermore, the content and goals of heroism training may go against schools’ and parents’ wishes. Heroism training programs also have the potential to make heroism seem glamorous, which could lead some participants to seek out, or create, situations requiring heroic action. The paper discusses these, and other, ethical concerns in training minors to be heroes. The paper concludes with a variety of best practice recommendations for heroism training programs working with minors including; obtaining parent consent for training, working to improve minors’ risk assessment abilities, domain specific training, and involving parents and other relevant stakeholders in the heroism training process

Probing the superconducting condensate on a nanometer scale

Superconductivity is a rare example of a quantum system in which the wavefunction has a macroscopic quantum effect, due to the unique condensate of electron pairs. The amplitude of the wavefunction is directly related to the pair density, but both amplitude and phase enter the Josephson current : the coherent tunneling of pairs between superconductors. Very sensitive devices exploit the superconducting state, however properties of the {\it condensate} on the {\it local scale} are largely unknown, for instance, in unconventional high-T$_c$ cuprate, multiple gap, and gapless superconductors. The technique of choice would be Josephson STS, based on Scanning Tunneling Spectroscopy (STS), where the condensate is {\it directly} probed by measuring the local Josephson current (JC) between a superconducting tip and sample. However, Josephson STS is an experimental challenge since it requires stable superconducting tips, and tunneling conditions close to atomic contact. We demonstrate how these difficulties can be overcome and present the first spatial mapping of the JC on the nanometer scale. The case of an MgB$_2$ film, subject to a normal magnetic field, is considered.Comment: 7 pages, 6 figure

Switching on the remote: a new perspective on accessibility in remote Australia

Learning Communities: International Journal of Learning in Social Contexts by https://www.cdu.edu.au/northern-institute/lcj is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.In remote Australia, access to people, goods, services, information and places is difficult because of extreme distances and climates, sparse population, remoteness from markets, and complex economic and socio-cultural dynamics. Most of remote Australia remains disconnected from both the digital revolution and the national transport network due to a lack of adequate infrastructure, affordable and reliable services, and, for most, poor digital literacy. This impedes service delivery including education and health services, economic development and wellbeing of remote residents; contributing to inequalities between remote and non-remote Australians. Whilst the concept of accessibility in transport and telecommunication goods and services is relatively well defined in an urban context and can be measured accordingly, the way accessibility is currently measured fails to capture the complexity of the remote Australian context. The article discusses some of the current knowledge gaps associated with studying accessibility levels in remote Australia with a particular focus on Central Australia. The article presents indicators and tools which could be used to evaluate access issues with practical applications for remote Australia. Developing an accessibility index for remote areas would enable the reconsideration of minimal requirements for sustainable livelihoods in remote areas and the development of effective and appropriate regional development policies and initiatives