Quantum point contacts as heat engines

The efficiency of macroscopic heat engines is restricted by the second law of thermodynamics. They can reach at most the efficiency of a Carnot engine. In contrast, heat currents in mesoscopic heat engines show fluctuations. Thus, there is a small probability that a mesoscopic heat engine exceeds Carnot's maximum value during a short measurement time. We illustrate this effect using a quantum point contact as a heat engine. When a temperature difference is applied to a quantum point contact, the system may be utilized as a source of electrical power under steady state conditions. We first discuss the optimal working point of such a heat engine that maximizes the generated electrical power and subsequently calculate the statistics for deviations of the efficiency from its most likely value. We find that deviations surpassing the Carnot limit are possible, but unlikely.Comment: 9 pages, 2 figures. Contribution to the Physica E special issue on "Frontiers in quantum electronic transport" in memory of Markus Buttiker. Published versio

“All The Daughters of My Father\u27s House, and All The Brothers Too”: Shakespeare’s Portrayal of Gender Fluidity

This paper analyzes how Shakespeare\u27s personal life influenced the relationship between Viola and Cesario in Twelfth Night through a feminist lens and an analysis of gender fluidity in the Elizabethan Era. It is a common misconception that conversations revolving around gender are a modern discussion. Shakespeare popularized the idea of gender fluidity in English literature in his play, Twelfth Night. At the height of Shakespeare’s career, he wrote many comedies, yet few tragedies, however, a tonal shift occurred after the death of his son, Hamnet. Shakespeare was father to a pair of fraternal twins, Judith and Hamnet. However, the death of Hamnet and the bereavement of Judith’s twin inspired the plot of Twelfth Night. My methodology of research focuses on Early modern England’s confounding stance on crossdressing, the duality of gender, and the psychological impact of losing a twin. Additionally, my primary sources are textual evidence regarding twinship from Twelfth Night and A Comedy of Errors. In the Elizabethan era, there were many beliefs on gender fluidity, especially that of women becoming men. Shakespeare incorporates this belief in Viola’s character after shipwrecking in Illyria and takes upon the identity of her late brother, Sebastian, under the alias Cesario. Through Shakespeare’s deconstruction of gender, he challenges the power play instilled in the world for a character like Viola to find a voice within Cesario

3D silicon pixel detectors for the ATLAS Forward Physics experiment

The ATLAS Forward Physics (AFP) project plans to install 3D silicon pixel detectors about 210 m away from the interaction point and very close to the beamline (2-3 mm). This implies the need of slim edges of about 100-200 $\mu$m width for the sensor side facing the beam to minimise the dead area. Another challenge is an expected non-uniform irradiation of the pixel sensors. It is studied if these requirements can be met using slightly-modified FE-I4 3D pixel sensors from the ATLAS Insertable B-Layer production. AFP-compatible slim edges are obtained with a simple diamond-saw cut. Electrical characterisations and beam tests are carried out and no detrimental impact on the leakage current and hit efficiency is observed. For devices without a 3D guard ring a remaining insensitive edge of less than 15 $\mu$m width is found. Moreover, 3D detectors are non-uniformly irradiated up to fluences of several 10$^{15}$ n$_{eq}$/cm$^2$ with either a focussed 23 GeV proton beam or a 23 MeV proton beam through holes in Al masks. The efficiency in the irradiated region is found to be similar to the one in the non-irradiated region and exceeds 97% in case of favourable chip-parameter settings. Only in a narrow transition area at the edge of the hole in the Al mask, a significantly lower efficiency is seen. A follow-up study of this effect using arrays of small pad diodes for position-resolved dosimetry via the leakage current is carried out.Comment: 10 pages, submitted to JINS

First estimate of the time delay in HE 1104-1805

We present first results from five years of spectrophotometric monitoring of the bright double QSO and gravitational lens HE 1104-1805. The quasar has varied considerably over this time, while the emission line fluxes appear to have remained constant. We have constructed monochromatic continuum light curves for components A and B, finding that B leads the variability. A quantitative analysis with the Pelt method gives a best estimate for the light travel time delay of about 0.73 years, although a value as low as 0.3 cannot yet be excluded. We discuss possible models for the QSO-lens configuration and use our measured time delay to predict the redshift of the lens, z_d. Finding that most likely z_d < 1, we can rule out the hitherto favoured values of z_d = 1.32 or 1.66. A new candidate is an absorption system at z=0.73, but the lens could also be an elliptical not detected in absorption.Comment: 4 pages, 4 figures, accepted for A&A, Letters to the edito

Regulatory governance and sector performance : methodology and evaluation for Electricity distribution in Latin America

This paper contributes to the literature that explores the link between regulatory governance and sector performance. The paper develops an index of regulatory governance and estimates its impact on sector performance, showing that indeed regulation and its governance matter. The authors use two unique databases: (i) the World Bank Performance Database, which contains detailed annual data for 250 private and public electricity companies in Latin America and the Caribbean; and (ii) the Electricity Regulatory Governance Database, which contains data on several aspects of the governance of electricity agencies in the region. The authors run different models to explain the impacts of change in ownership and different characteristics of the regulatory agency on the performance of the utilities. The results suggest that the mere existence of a regulatory agency, regardless of the utilities'ownership, has a significant impact on performance. Furthermore, after controlling for the existence of a regulatory agency, the ownership dummies are still significant and with the expected signs. The authors propose an experience measure in order to identify the gradual impact of the regulatory agency on utility performance. The results confirm this hypothesis. In addition, the paper explores two different measures of governance, an aggregate measure of regulatory governance, and an index based on principal components, including autonomy, transparency, and accountability. The findings show that the governance of regulatory agencies matters and has significant effects on performance.National Governance,Infrastructure Regulation,Governance Indicators,Banks&Banking Reform,Emerging Markets

IMPACT OF RESOURCE SCARCITY ON UNDOCUMENTED STUDENTS IN HIGHER EDUCATION

Background: Much progress has been made in understanding the impacts of identifying as an undocumented student in higher education, but knowledge of the scarcity of resources impacting undocumented students remains limited. Objective: This descriptive study examined the relationship between accessibility to social support and the psychological well-being of undocumented students in higher education. Methods: Quantitative data was gathered cross-sectionally from participants recruited using nonprobability sampling methods. The Kessler Psychological Distress Scale and Social Support Survey Scale were used to gather data on participants\u27 psychological distress and social support. A descriptive analysis was performed to yield summary statistics of participants’ demographics, psychological well-being, and social support. Results: All participants identified as Hispanic or Latino, most are attending a 4-year college, and most participants’ parents have less than a college education. The data suggests that 100% of participants reported struggles with mental health. Additionally, most reported less than favorable levels of social support throughout their academic career in higher education. Conclusion: The mental health of undocumented students may be more complex than anticipated, where mental well-being may be impacted by factors beyond the levels and types of social support received. Future research should consider exploring other factors that might impact the mental wellness of undocumented students. Furthermore, Colleges serving undocumented students should ensure that this vulnerable group receives adequate educational support in efforts to boost their mental health