InAs-AlSb quantum wells in tilted magnetic fields

InAs-AlSb quantum wells are investigated by transport experiments in magnetic fields tilted with respect to the sample normal. Using the coincidence method we find for magnetic fields up to 28 T that the spin splitting can be as large as 5 times the Landau splitting. We find a value of the g-factor of about 13. For small even-integer filling factors the corresponding minima in the Shubnikov-de Haas oscillations cannot be tuned into maxima for arbitrary tilt angles. This indicates the anti-crossing of neighboring Landau and spin levels. Furthermore we find for particular tilt angles a crossover from even-integer dominated Shubnikov-de Haas minima to odd-integer minima as a function of magnetic field

Andreev magnetotransport in low-dimensional proximity structures: Spin-dependent conductance enhancement

We study the excess conductance due to the superconducting proximity effect in a ballistic two-dimensional electron system subject to an in-plane magnetic field. We show that under certain conditions the interplay of the Zeeman spin splitting and the effect of a screening supercurrent gives rise to a spin-selective Andreev enhancement of the conductance and anomalies in its voltage, temperature and magnetic field characteristics. The magnetic-field influence on Andreev reflection is discussed in the context of using superconducting hybrid junctions for spin detection.Comment: 4 pages, 5 figure

Pediatric Psychologists’ Career Satisfaction: 2015 Society of Pediatric Psychology Workforce Survey Results.

Little is known about the career satisfaction of pediatric psychologists, who specialize in psychological research, teaching, and clinical service in the context of pediatric health care. As part of the larger Society of Pediatric Psychology Workforce Survey and in collaboration with the American Psychological Association Center for Workforce Studies, this study aimed to (1) describe the career domains which pediatric psychologists perceive to be important and their satisfaction in each domain, and (2) compare satisfaction of pediatric psychologists across work settings, number of positions, appointment duration, professional roles, career stage, academic rank, and gender. Responses from 336 pediatric psychologists demonstrated high career satisfaction. Domains of career satisfaction that received mean scores indicating high importance include balance of work and personal lives, peer/collegial support, and flexibility and choice in the workplace, but on average respondents reported being only somewhat satisfied in these domains. Total satisfaction scores were significantly higher among pediatric psychologists in 9–10-month appointments, primarily research careers, and at higher academic ranks, but scores were similar across employment settings and genders. To enhance career satisfaction and retention, pediatric psychologists may seek additional mentorship or explore new employment roles, and administrators and managers may consider adopting workplace policies or making environmental changes that could address specific areas of need

D-SPACE4Cloud: A Design Tool for Big Data Applications

The last years have seen a steep rise in data generation worldwide, with the development and widespread adoption of several software projects targeting the Big Data paradigm. Many companies currently engage in Big Data analytics as part of their core business activities, nonetheless there are no tools and techniques to support the design of the underlying hardware configuration backing such systems. In particular, the focus in this report is set on Cloud deployed clusters, which represent a cost-effective alternative to on premises installations. We propose a novel tool implementing a battery of optimization and prediction techniques integrated so as to efficiently assess several alternative resource configurations, in order to determine the minimum cost cluster deployment satisfying QoS constraints. Further, the experimental campaign conducted on real systems shows the validity and relevance of the proposed method

Forum: Complex Systems and International Governance

That we live in an age of complexity and transition is hardly news. Ours is the age of interconnections, ambiguity, and uncertainty; of the diffusion of authority; of various kinds of revolutions: military, technological, social, political, economic, and even philosophical. What springs from these developments is the feeling of a lack of control. Decision-makers either think they have no other option but to act as they do or are paralyzed by the uncertainties and conflicting pressures they face. The usual solution is to try to reassert control, which leads to new problems. Paradoxically, as our tools to make sense and control societies and our environment increase, our ability to do so diminishes

Magnetotunneling Between Two-dimensional Electron Gases in InAs-AlSb-GaSb Heterostructures

We have observed that the tunneling magnetoconductance between two-dimensional (2D) electron gases formed at nominally identical InAs-AlSb interfaces most often exhibits two sets of Shubnikov-de Haas oscillations with almost the same frequency. This result is explained quantitatively with a model of the conductance in which the 2D gases have different densities and can tunnel between Landau levels with different quantum indices. When the epitaxial growth conditions of the interfaces are optimized, the zero-bias magnetoconductance shows a single set of oscillations, thus proving that the asymmetry between the two electron gases can be eliminated.Comment: RevTeX format including 4 figures; submit for publicatio

Conductance fluctuations in diffusive rings: Berry phase effects and criteria for adiabaticity

We study Berry phase effects on conductance properties of diffusive mesoscopic conductors, which are caused by an electron spin moving through an orientationally inhomogeneous magnetic field. Extending previous work, we start with an exact, i.e. not assuming adiabaticity, calculation of the universal conductance fluctuations in a diffusive ring within the weak localization regime, based on a differential equation which we derive for the diffuson in the presence of Zeeman coupling to a magnetic field texture. We calculate the field strength required for adiabaticity and show that this strength is reduced by the diffusive motion. We demonstrate that not only the phases but also the amplitudes of the h/2e Aharonov-Bohm oscillations are strongly affected by the Berry phase. In particular, we show that these amplitudes are completely suppressed at certain magic tilt angles of the external fields, and thereby provide a useful criterion for experimental searches. We also discuss Berry phase-like effects resulting from spin-orbit interaction in diffusive conductors and derive exact formulas for both magnetoconductance and conductance fluctuations. We discuss the power spectra of the magnetoconductance and the conductance fluctuations for inhomogeneous magnetic fields and for spin-orbit interaction.Comment: 18 pages, 13 figures; minor revisions. To appear in Phys. Rev.