Multifractal analysis of the electronic states in the Fibonacci superlattice under weak electric fields

Influence of the weak electric field on the electronic structure of the Fibonacci superlattice is considered. The electric field produces a nonlinear dynamics of the energy spectrum of the aperiodic superlattice. Mechanism of the nonlinearity is explained in terms of energy levels anticrossings. The multifractal formalism is applied to investigate the effect of weak electric field on the statistical properties of electronic eigenfunctions. It is shown that the applied electric field does not remove the multifractal character of the electronic eigenfunctions, and that the singularity spectrum remains non-parabolic, however with a modified shape. Changes of the distances between energy levels of neighbouring eigenstates lead to the changes of the inverse participation ratio of the corresponding eigenfunctions in the weak electric field. It is demonstrated, that the local minima of the inverse participation ratio in the vicinity of the anticrossings correspond to discontinuity of the first derivative of the difference between marginal values of the singularity strength. Analysis of the generalized dimension as a function of the electric field shows that the electric field correlates spatial fluctuations of the neighbouring electronic eigenfunction amplitudes in the vicinity of anticrossings, and the nonlinear character of the scaling exponent confirms multifractality of the corresponding electronic eigenfunctions.Comment: 10 pages, 9 figure

Hamiltonian Dynamics and the Phase Transition of the XY Model

A Hamiltonian dynamics is defined for the XY model by adding a kinetic energy term. Thermodynamical properties (total energy, magnetization, vorticity) derived from microcanonical simulations of this model are found to be in agreement with canonical Monte-Carlo results in the explored temperature region. The behavior of the magnetization and the energy as functions of the temperature are thoroughly investigated, taking into account finite size effects. By representing the spin field as a superposition of random phased waves, we derive a nonlinear dispersion relation whose solutions allow the computation of thermodynamical quantities, which agree quantitatively with those obtained in numerical experiments, up to temperatures close to the transition. At low temperatures the propagation of phonons is the dominant phenomenon, while above the phase transition the system splits into ordered domains separated by interfaces populated by topological defects. In the high temperature phase, spins rotate, and an analogy with an Ising-like system can be established, leading to a theoretical prediction of the critical temperature $T_{KT}\approx 0.855$.Comment: 10 figures, Revte

Self-consistent Wigner distribution function study of gate-voltage controlled triple-barrier resonant tunnelling diode

The electron transport through the triple-barrier resonant tunnelling diode (TBRTD) have been studied by the self-consistent numerical method for the Wigner-Poisson problem. The electron flow through the TBRTD can be controlled by the gate voltage applied to one of the potential well regions. For different gate voltage values we have determined the current-voltage characteristics, potential energy profiles, and electron density distribution. We have found the enhancement of the peak-to-valley ratio (up to $\sim$10), the appearance of the linear current versus bias voltage behaviour within the negative-differential resistance region, and the bistability of the current-voltage characteristics. The analysis of the self-consistent potential energy profiles and electron density distribution allowed us to provide a physical interpretation of these properties.Comment: 13 pages, 7 figure

The General Age of Leadership: Older-Looking Presidential Candidates Win Elections during War

As nation-state leaders age they increasingly engage in inter-state militarized disputes yet in industrialized societies a steady decrease in testosterone associated with aging is observed – which suggests a decrease in dominance behavior. The current paper points out that from modern societies to Old World monkeys increasing both in age and social status encourages dominant strategies to maintain acquired rank. Moreover, it is argued this consistency has shaped an implicit prototype causing followers to associate older age with dominance leadership. It is shown that (i) faces of older leaders are preferred during intergroup conflict and (ii) morphing U.S. Presidential candidates to appear older or younger has an overriding effect on actual election outcomes. This indicates that democratic voting can be systematically adjusted by activating innate biases. These findings appear to create a new line of research regarding the biology of leadership and contextual cues of age

Detecting Neuroendocrine Prostate Cancer Through Tissue-Informed Cell-Free DNA Methylation Analysis

Purpose: Neuroendocrine prostate cancer (NEPC) is a resistance phenotype that emerges in men with metastatic castration-resistant prostate adenocarcinoma (CR-PRAD) and has important clinical implications, but is challenging to detect in practice. Herein, we report a novel tissue-informed epigenetic approach to noninvasively detect NEPC. Experimental Design: We first performed methylated immunoprecipitation and high-throughput sequencing (MeDIP-seq) on a training set of tumors, identified differentially methylated regions between NEPC and CR-PRAD, and built a model to predict the presence of NEPC (termed NEPC Risk Score). We then performed MeDIP-seq on cell-free DNA (cfDNA) from two independent cohorts of men with NEPC or CR-PRAD and assessed the accuracy of the model to predict the presence NEPC. Results: The test cohort comprised cfDNA samples from 48 men, 9 with NEPC and 39 with CR-PRAD. NEPC Risk Scores were significantly higher in men with NEPC than CR-PRAD (P = 4.3 × 10-7) and discriminated between NEPC and CR-PRAD with high accuracy (AUROC 0.96). The optimal NEPC Risk Score cutoff demonstrated 100% sensitivity and 90% specificity for detecting NEPC. The independent, multi-institutional validation cohort included cfDNA from 53 men, including 12 with NEPC and 41 with CR-PRAD. NEPC Risk Scores were significantly higher in men with NEPC than CR-PRAD (P = 7.5×10-12) and perfectly discriminated NEPC from CR-PRAD (AUROC 1.0). Applying the predefined NEPC Risk Score cutoff to the validation cohort resulted in 100% sensitivity and 95% specificity for detecting NEPC. Conclusions: Tissue-informed cfDNA methylation analysis is a promising approach for noninvasive detection of NEPC in men with advanced prostate cancer

Reading the face of a leader: women with low facial masculinity are perceived as competitive

In competitive settings, people prefer leaders with masculine faces. But is facial masculinity a trait that is similarly desired in men and women leaders? Across three studies, we discovered that people indeed prefer men and women leaders who have faces with masculine traits. But surprisingly, we find that people also prefer women with low facial masculinity as leaders in competitive contexts (Study 1). Our findings indicate that low facial masculinity in women, but not in men is perceived to indicate competitiveness (Study 2). Thus, in contrast to men, women leaders who rate high in facial masculinity as well as those low in facial masculinity are both selected as leaders in competitive contexts. Indeed, among CEOs of S&P 500 companies, we find a greater range of facial masculinity amongwomen CEOs than among men CEOs (Study 3). Our results suggest that traits of facial masculinity in men and women are interpreted differently. Low facial masculinity in women is linked to competitiveness and not only to cooperativeness as suggested by prior research

The Simons Observatory: Cryogenic Half Wave Plate Rotation Mechanism for the Small Aperture Telescopes

We present the requirements, design and evaluation of the cryogenic continuously rotating half-wave plate (CHWP) for the Simons Observatory (SO). SO is a cosmic microwave background (CMB) polarization experiment at Parque Astron\'{o}mico Atacama in northern Chile that covers a wide range of angular scales using both small (0.42 m) and large (6 m) aperture telescopes. In particular, the small aperture telescopes (SATs) focus on large angular scales for primordial B-mode polarization. To this end, the SATs employ a CHWP to modulate the polarization of the incident light at 8~Hz, suppressing atmospheric $1/f$ noise and mitigating systematic uncertainties that would otherwise arise due to the differential response of detectors sensitive to orthogonal polarizations. The CHWP consists of a 505 mm diameter achromatic sapphire HWP and a cryogenic rotation mechanism, both of which are cooled down to $\sim$50 K to reduce detector thermal loading. Under normal operation the HWP is suspended by a superconducting magnetic bearing and rotates with a constant 2 Hz frequency, controlled by an electromagnetic synchronous motor. The rotation angle is detected through an angular encoder with a noise level of 0.07$\mu\mathrm{rad}\sqrt{\mathrm{s}}$. During a cooldown, the rotor is held in place by a grip-and-release mechanism that serves as both an alignment device and a thermal path. In this paper we provide an overview of the SO SAT CHWP: its requirements, hardware design, and laboratory performance.Comment: 19 pages, 21 figures, submitted to RS

Planning oral health care using the sociodental approach and the index of family living conditions: a cross-sectional study in Brazilian adolescents.

BACKGROUND: Oral health care needs assessment is frequently restricted to clinical measures. Combining normative assessment, behavioural propensity, oral health-related quality of life and information of family living conditions may provide a better comprehensive approach of adolescent's oral health needs assessment. The aim of this study was to compare normative methods of dental caries need with the sociodental approach in 12-year-old adolescents according to family's living conditions in a deprived community in Brazil. In addition, dental caries need assessment using the normative method and the sociodental approach was compared between adolescents living in different living conditions. METHODS: A cross-sectional survey was conducted in the Manguinhos community in the city of Rio de Janeiro, Brazil. A weighted sample of 159 participants was randomly selected to represent the population of 2004 12-year-old adolescents. Socioeconomic characteristics and living conditions of the family were assessed using the Family Development Index (FDI). Oral health-related quality of life (OHRQoL) was assessed using the generic and CS-Child-OIDP, and adolescent's propensity to adopt oral health promoting behaviours was verified through interviews. Dental caries and treatment need were assessed normatively by clinical oral examinations (DMFT Index) and adolescents were classified into two groups (non severe or severe caries). The sociodental approach included clinical measures of caries, propensity to adopt oral health promoting behaviors and OHRQoL. Families were classified based on the FDI as 'not severe', 'severe' and 'very severe'. Measures of caries, OHRQoL and propensity outcomes were compared between FDI groups using Chi-square and Kruskal-Wallis tests. In addition, dental treatment needs using normative method and sociodental approach were compared for the whole sample and according to FDI groups. RESULTS: Dental caries, OHRQoL and lower propensity needs were positively associated with FDI severity. The percentages of adolescents with normative dental needs from families with 'very severe', 'severe' and 'not severe' FDI were 59.3, 48.4 and 17.2 % (P < 0.05). Using the sociodental approach, the treatment needs for the three FDI groups decreased to 8.8, 13.6 and 8.6 %, respectively (P < 0.05). CONCLUSIONS: Using a combination of sociodental approach and the index of family living conditions was useful for defining dental care priorities in adolescents living in deprived communities and can optimise the use of resources in dental services