Noise properties of two single electron transistors coupled by a nanomechanical resonator

We analyze the noise properties of two single electron transistors (SETs) coupled via a shared voltage gate consisting of a nanomechanical resonator. Working in the regime where the resonator can be treated as a classical system, we find that the SETs act on the resonator like two independent heat baths. The coupling to the resonator generates positive correlations in the currents flowing through each of the SETs as well as between the two currents. In the regime where the dynamics of the resonator is dominated by the back-action of the SETs, these positive correlations can lead to parametrically large enhancements of the low frequency current noise. These noise properties can be understood in terms of the effects on the SET currents of fluctuations in the state of a resonator in thermal equilibrium which persist for times of order the resonator damping time.Comment: Accepted for publication in Phys. Rev.

Evidence of spontaneous spin polarized transport in magnetic nanowires

The exploitation of the spin in charge-based systems is opening revolutionary opportunities for device architecture. Surprisingly, room temperature electrical transport through magnetic nanowires is still an unresolved issue. Here, we show that ferromagnetic (Co) suspended atom chains spontaneously display an electron transport of half a conductance quantum, as expected for a fully polarized conduction channel. Similar behavior has been observed for Pd (a quasi-magnetic 4d metal) and Pt (a non-magnetic 5d metal). These results suggest that the nanowire low dimensionality reinforces or induces magnetic behavior, lifting off spin degeneracy even at room temperature and zero external magnetic field.Comment: 4 pages, 3 eps fig

Heteronormative beliefs and internalized homonegativity in the coming out process of Portuguese and Turkish sexual minority men

Introduction Studies examining why heteronormative beliefs shape the coming out process of sexual minority men are still scarce. This study aimed to examine whether heteronormative beliefs result in more internalized homonegativity and more sexual identity stigma. We also compared socio-cultural contexts—Portugal and Turkey—with distinct social policies toward sexual minority people. Lastly, we explored the correlates of coming out to friends and family members. Methods A cross-sectional study with 562 sexual minority men (93.4% cisgender; Mage = 26.69, SD = 9.59) from Portugal and Turkey was conducted between March and July 2019. Results Heteronormative beliefs were associated with increased internalized homonegativity and, in turn, with increased sexual identity stigma (identity stigma and social discomfort). This mediation was moderated by country, such that conditional direct effects were stronger among Turkish sexual minority men. Conditional indirect effects, however, were stronger among Portuguese sexual minority men. Furthermore, less internalized homonegativity and less social discomfort were associated with coming out to friends and family members in different ways. Conclusions This study contributed to the understanding of sexual identity development and acceptance among sexual minority men in two distinct socio-cultural contexts. Findings showed that the internalization of heteronormative beliefs was associated with identity stigma and highlighted the role of socialization in these processes. Policy Implications For people working with sexual minority men from diverse socio-cultural contexts, our findings can offer new insights on how to offer the best help in the coming out process of these sexual minority men.info:eu-repo/semantics/acceptedVersio

Early-age strength measurement of shotcrete

Shotcrete or sprayed concrete is a special concrete designed for spraying onto a surface, as a construction material. With shotcrete application as a ground support system ever-present in both mining and tunnelling sectors, a major requirement of drive progression is to determine when it is safe to re-enter beneath freshly sprayed concrete. Accurately determining this time is of paramount importance. Generally, this re-entry time is based on measuring the developing strength of shotcrete until an adequate strength value is reached. The issue with current practice is that there is no widely accepted or generally preferred method that accurately assesses the shotcrete lining's true early-age strength. However, there are a number of strength tests that are commercially available and used in the industry, these include the soil penetrometer, needle penetrometer, bolt screws, beam end testers and drilled core samples. This paper researches into these testing methods and their characteristics in order to determine their accuracy, testing ranges and suitability for in situ use in the tunnelling and mining industry. The paper then looks into what advancements or developments in testing technology would be of benefit to the underground industries. The investigation ultimately reveals that current methods all have substantial shortcomings. Based on these findings, recommendations are proposed for the applicable use of the current testing methods and recommendations for future improvements

Regulatory focus and sexual health: Motives for security and pleasure in sexuality are associated with distinct protective behaviors

We examined if motives for security (i.e., prevention focus) or pleasure (i.e., promotion focus) were uniquely associated with intentions to get tested for STIs and behavioral control over condom use, over and above variables already identified in theoretical models. We conducted an online survey with Portuguese adults (N = 836; Mage = 22.27, SD = 5.14). Overall, 99.4% of the participants knew at least one of eight STIs, but only 25.2% got tested in the last six months. Participants more focused on prevention had condomless sex less frequently, whereas participants more focused on promotion knew more STIs and got tested for more STIs. Furthermore, participants had stronger intentions to get tested for STIs if they got tested for more STIs in the past, were more concerned about STIs, perceived greater susceptibility to STI acquisition, and were more focused on promotion (but not prevention). Participants had greater behavioral control over condom use if they had condomless sex less often and were more focused on prevention (but not promotion). These findings suggest that promotion-focused people are more likely to consider the consequences of having condomless sex. In contrast, prevention-focused people are more likely to take control of their sexual health.info:eu-repo/semantics/acceptedVersio

Dynamical instabilities of a resonator driven by a superconducting single-electron transistor

We investigate the dynamical instabilities of a resonator coupled to a superconducting single-electron transistor (SSET) tuned to the Josephson quasiparticle (JQP) resonance. Starting from the quantum master equation of the system, we use a standard semiclassical approximation to derive a closed set of mean field equations which describe the average dynamics of the resonator and SSET charge. Using amplitude and phase coordinates for the resonator and assuming that the amplitude changes much more slowly than the phase, we explore the instabilities which arise in the resonator dynamics as a function of coupling to the SSET, detuning from the JQP resonance and the resonator frequency. We find that the locations (in parameter space) and sizes of the limit cycle states predicted by the mean field equations agree well with numerical solutions of the full master equation for sufficiently weak SSET-resonator coupling. The mean field equations also give a good qualitative description of the set of dynamical transitions in the resonator state that occur as the coupling is progressively increased.Comment: 23 pages, 6 Figures, Accepted for NJ