Single electron charging of impurity sites visualized by scanning gate experiments on a quantum point contact

A quantum point contact (QPC) patterned on a two-dimensional electron gas is investigated with a scanning gate setup operated at a temperature of 300 mK. The conductance of the point contact is recorded while the local potential is modified by scanning the tip. Single electron charging of impurities induced by the local potential is observed as a stepwise conductance change of the constriction. By selectively changing the state of some of these impurities, it is possible to observe changes in transmission resonances of the QPC. The location of such impurities is determined, and their density is estimated to be below 50 per \mu m^2, corresponding to less than 1 % of the doping concentration

Dynamically-Coupled Oscillators -- Cooperative Behavior via Dynamical Interaction --

We propose a theoretical framework to study the cooperative behavior of dynamically coupled oscillators (DCOs) that possess dynamical interactions. Then, to understand synchronization phenomena in networks of interneurons which possess inhibitory interactions, we propose a DCO model with dynamics of interactions that tend to cause 180-degree phase lags. Employing an approach developed here, we demonstrate that although our model displays synchronization at high frequencies, it does not exhibit synchronization at low frequencies because this dynamical interaction does not cause a phase lag sufficiently large to cancel the effect of the inhibition. We interpret the disappearance of synchronization in our model with decreasing frequency as describing the breakdown of synchronization in the interneuron network of the CA1 area below the critical frequency of 20 Hz.Comment: 10 pages, 3 figure

All my rowdy friends: the effect of Super Bowl hosting on audit and financial reporting timeliness

Purpose The purpose of this paper is to examine the impact hosting the Super Bowl has on audit completion and financial reporting timeliness for companies headquartered in Super Bowl hosting cities. Design/methodology/approach Using 16 years of financial reporting data, this study uses the Super Bowl and related activities, combined with required filings during “busy season,” as a natural experiment to examine how audit firms navigate short-term, exogenously imposed but anticipated, audit team capacity constraints. Findings Companies headquartered in a city hosting the Super Bowl, during busy season, have longer audit report lags (by approximately three days, in comparison to non-hosting busy season audits) and less timely securities and exchange commission (SEC) (10-K) filings. The authors find no evidence that Super Bowl hosting affects audit fees or earnings announcement timeliness. Practical implications When confronted with anticipated capacity shocks, audit firms take longer to complete the audit, absorbing the financial costs of the delay and maintaining audit quality, resulting in less timely financial reporting. Originality/value This study demonstrates the costs of Super Bowl-related inefficiencies and contributes to our understanding of how auditors navigate capacity shocks. This study provides evidence that auditors can effectively manage business risk and continue to facilitate providing timely and accurate information to financial statement users in the face of a capacity shock

Spatial dependence of the superexchange interactions for transition-metal trimers in graphene

This study examines the magnetic interactions between spatially-variable manganese and chromium trimers substituted into a graphene superlattice. Using density functional theory, we calculate the electronic band structure and magnetic populations for the determination of the electronic and magnetic properties of the system. To explore the super-exchange coupling between the transition-metal atoms, we establish the magnetic magnetic ground states through a comparison of multiple magnetic and spatial configurations. Through an analysis of the electronic and magnetic properties, we conclude that the presence of transition-metal atoms can induce a distinct magnetic moment in the surrounding carbon atoms as well as produce an RKKY-like super-exchange coupling. It hoped that these simulations can lead to the realization of spintronic applications in graphene through electronic control of the magnetic clusters.Comment: 6 pages, 5 Figur

Kombinierte dorsale und palmare Plattenosteosynthese bei distalen intraartikulären Radiusfrakturen

Zusammenfassung: Hintergrund: Behandlungsziel bei komplexen distalen intraartikulären Radiusfrakturen ist die anatomische Gelenkrekonstruktion. In seltenen Fällen kann dies nur mit einer kombinierten, dorsalen und palmaren Abstützung erreicht werden, trotz der zunehmenden Erfahrung mit winkelstabilen palmaren Implantaten. Diese retrospektive Qualitätskontrollstudie untersucht das funktionelle, radiologische und subjektive Outcome der mit dieser Technik operierten Patienten. Patienten und Methoden : An der Klinik für Unfallchirurgie des Universitätsspital Zürich wurden zwischen März 1999 und Januar 2003 von 360 Patienten mit instabiler distaler Radiusfraktur 30 Patienten mit komplexer C2-/C3-Fraktur über einen kombinierten dorsopalmaren Zugang mit einer 3,5-mm-T-Platte und dorsal mit zwei 1/4-Rohr-Platten behandelt und in die Studie eingeschlossen (9 Frauen, 21Männer, Mittelwert des Alters 52). Nachkontrolliert werden konnten 25 der 30 Patienten im Mittel 29 Monate nach Unfall. Ergebnisse: Die angestrebte anatomische Rekonstruktion gelang nicht bei allen Patienten: 56% zeigten leichte, 28% schwere Zeichen der Arthrose. Die Flexion erreichte 66%, die Extension 75% der gesunden Seite, Pronation und Supination sogar 98 bzw. 91%. Die Kraft beim Faustschluss betrug 75% der kontralateralen Seite. Zehn Patienten (40%) entwickelten im Verlauf ein komplexes regionales Schmerzsyndrom (CRPS). Die Rückkehr zur Arbeit war nach 120 Tagen möglich. Schlussfolgerung: Die dorsopalmare Plattenosteosynthese komplexer, distaler intraartikulärer Radiusfrakturen erlaubt eine Gelenkrekonstruktion mit gutem subjektivem, funktionellem und radiologischem Resultat, dies trotz des durch den beidseitigen Zugang verursachten zusätzlichen Weichteilschaden. Das hohe CRPS-Risiko, aber auch der lange Arbeitsausfall müssen bei der Patientenaufklärung berücksichtigt werde

Taste and safety : is the exceptional cuisine offered by high end restaurants paralleled by high standards of food safety?

Introduction: Restaurant guides such as the Good Food Guide Top 50 create a hierarchy focussing on taste and sophistication. Safety is not explicitly included. We used restaurant associated outbreaks to assess evidence for safety. Methods: All foodborne disease outbreaks in England reported to the national database from 2000 to 2014 were used to compare the Top 50 restaurants (2015) to other registered food businesses using the Public Health England (PHE) outbreak database. Health Protection Teams were also contacted to identify any outbreaks not reported to the national database. Among Good Food Guide Top 50 restaurants, regression analysis estimated the association between outbreak occurrence and position on the list. Results: Four outbreaks were reported to the PHE national outbreak database among the Top 50 giving a rate 39 times higher (95% CI 14.5–103.2) than other registered food businesses. Eight outbreaks among the 44 English restaurants in the Top 50 were identified by direct contact with local Health Protection Teams. For every ten places higher ranked, Top 50 restaurants were 66% more likely to have an outbreak (Odds Ratio 1.66, 95% CI 0.89–3.13). Discussion: Top 50 restaurants were substantially more likely to have had reported outbreaks from 2000-2014 than other food premises, and there was a trend for higher rating position to be associated with higher probability of reported outbreaks. Our findings, that eating at some of these restaurants may pose an increased risk to health compared to other dining out, raises the question of whether food guides should consider aspects of food safety alongside the clearly important complementary focus on taste and other aspects of the dining experience

The relationships between expressed emotion, cortisol, and EEG alpha asymmetry

Families can express high criticism, hostility and emotional over-involvement towards a person with or at risk of mental health problems. Perceiving such high expressed emotion (EE) can be a major psychological stressor for individuals, especially those at risk of mental health problems. To reveal the biological mechanisms underlying the effect of EE on health, this study investigated physiological response (salivary cortisol, frontal alpha asymmetry (FAA)) to verbal criticism and their relationship to anxiety and perceived EE. Using a repeated-measures design, healthy participants attended three testing sessions on non-consecutive days. On each day, participants listened to one of three types of auditory stimuli, namely criticism, neutral or praise, and Electroencephalography (EEG) and salivary cortisol were measured. Results showed a reduction in cortisol following criticism but there was no significant change in FAA. Post-criticism cortisol concentration negatively correlated with perceived EE after controlling for baseline mood. Our findings suggest that salivary cortisol change responds to criticism in non-clinical populations might be largely driven by individual differences in the perception of criticism (e.g., arousal and relevance). Criticisms expressed by audio comments may not be explicitly perceived as an acute emotional stressor, and thus, physiological change responds to criticisms could be minimum

Combining Charlson and Elixhauser scores with varying lookback predicated mortality better than using individual scores

Objective: To investigate variation in the presence of secondary diagnosis codes in Charlson and Elixhauser comorbidity scores and assess whether including a 1-year lookback period improved prognostic adjustment by these scores individually, and combined, for 30-day mortality. Study Design and Setting: We analyzed inpatient admissions from January 1, 2007 to May 18, 2018 in Oxfordshire, UK. Comorbidity scores were calculated using secondary diagnostic codes in the diagnostic-dominant episode, and primary and secondary codes from the year before. Associations between scores and 30-day mortality were investigated using Cox models with natural cubic splines for nonlinearity, assessing fit using Akaike Information Criteria. Results: The 1-year lookback improved model fit for Charlson and Elixhauser scores vs. using diagnostic-dominant methods. Including both, and allowing nonlinearity, improved model fit further. The diagnosis-dominant Charlson score and Elixhauser score using a 1-year lookback, and their interaction, provided the best comorbidity adjustment (reduction in AIC: 761 from best single score model). Conclusion: The Charlson and Elixhauser score calculated using primary and secondary diagnostic codes from 1-year lookback with secondary diagnostic codes from the current episode improved individual predictive ability. Ideally, comorbidities should be adjusted for using both the Charlson (diagnostic-dominant) and Elixhauser (1-year lookback) scores, incorporating nonlinearity and interactions for optimal confounding control

Design principles governing the development of theranostic anticancer agents and their nanoformulations with photoacoustic properties

The unmet need to develop novel approaches for cancer diagnosis and treatment has led to the evolution of theranostic agents, which usually include, in addition to the anticancer drug, an imaging agent based mostly on fluorescent agents. Over the past few years, a non-invasive photoacoustic imaging modality has been effectively integrated into theranostic agents. Herein, we shed light on the design principles governing the development of theranostic agents with photoacoustic properties, which can be formulated into nanocarriers to enhance their potency. Specifically, we provide an extensive analysis of their individual constituents including the imaging dyes, drugs, linkers, targeting moieties, and their formulation into nanocarriers. Along these lines, we present numerous relevant paradigms. Finally, we discuss the clinical relevance of the specific strategy, as also the limitations and future perspectives, and through this review, we envisage paving the way for the development of theranostic agents endowed with photoacoustic properties as effective anticancer medicines