Exact polarizability and plasmon resonances of partly buried nanowires

The electrostatic polarizability for both vertical and horizontal polarization of two conjoined half-cylinders partly buried in a substrate is derived in an analytical closed-form expression. Using the derived analytical polarizabilities we analyze the localized surface plasmon resonances of three important metal nanowire configurations: (1) a half-cylinder, (2) a half-cylinder on a substrate, and (3) a cylinder partly buried in a substrate. Among other results we show that the substrate plays an important role for spectral location of the plasmon resonances. Our analytical results enable an easy, fast, and exact analysis of many complicated plasmonic nanowire configurations including nanowires on substrates. This is important both for comparison with experimental data, for applications, and as benchmarks for numerical methods

Polarizability of nanowires at surfaces: Exact solution for general geometry

The polarizability of a nanostructure is an important parameter that determines the optical properties. An exact semi-analytical solution of the electrostatic polarizability of a general geometry consisting of two segments forming a cylinder that can be arbitrarily buried in a substrate is derived using bipolar coordinates, cosine-, and sine-transformations. Based on the presented expressions, we analyze the polarizability of several metal nanowire geometries that are important within plasmonics. Our results provide physical insight into the interplay between the multiple resonances found in the polarizability of metal nanowires at surfaces

Can gravitational infall energy lead to the observed velocity dispersion in DLAs?

The median observed velocity width v_90 of low-ionization species in damped Ly-alpha systems is close to 90 km/s, with approximately 10% of all systems showing v_90 > 210 km/s at z=3. We show that a relative shortage of such high-velocity neutral gas absorbers in state-of-the-art galaxy formation models is a fundamental problem, present both in grid-based and particle-based numerical simulations. Using a series of numerical simulations of varying resolution and box size to cover a wide range of halo masses, we demonstrate that energy from gravitational infall alone is insufficient to produce the velocity dispersion observed in damped Ly-alpha systems, nor does this dispersion arise from an implementation of star formation and feedback in our highest resolution (~ 45 pc) models, if we do not put any galactic winds into our models by hand. We argue that these numerical experiments highlight the need to separate dynamics of different components of the multiphase interstellar medium at z=3.Comment: 12 Pages, 9 Figures, accepted to ApJ, printing in colour recommende

CEO personality traits, strategic flexibility, and firm dynamics

Reexamining CEO personality traits from a real options theory perspective, we suggest that the firm's strategic flexibility can be worsened by CEO conscientiousness and neuroticism. We use a measure of strategic flexibility as the firm's ability to take advantage of heightened volatility, which then results in superior stock returns. Our results suggest that strategic adaptability is impeded by rigid planning, resistance to change (conscientiousness) and lack of emotional stability (neuroticism). For firms that experience a decrease in volatility, the opposite holds. In line with trait activation theory, our results imply that the effect of specific CEO personality traits on firm dynamics and performance is contingent and context-specific. Our findings are economically significant and have important implications concerning CEO selection and management

Health and performance effects of 12 weeks of small-sided street football training compared to grass football training in habitually active young men

Purpose - The purpose of the present study was to investigate the health and exercise performance effects of street football training on very small pitches surrounded by boards in young habitually active men in comparison to small-sided football training on grass. Methods - Thirty-nine habitually active men (30.7 ± 6.7 years, 90.9 ± 16.6 kg, 183.8 ± 4.5 cm, 39.6 ± 6.0 mL/min/kg) were randomly assigned to a street football training group (ST) or grass football group (GR) playing small-sided games for 70 min, 1.5 and 1.7 times per week for 12 weeks, respectively, or an inactive control group (CO). Intensity during training was measured using heart rate (HR) and GPS units. Pre- and post-intervention, a test battery was completed. Results - Mean HR (87.1 ± 5.0 vs. 84.0 ± 5.3%HRmax; P > 0.05) and percentage of training time above 90%HRmax (44 ± 28 vs. 34 ± 24%; P > 0.05) were not different between ST and GR. VO2max increased (P  Conclusion - Small-sided street football training for 12 weeks with 1–2 weekly sessions led to improvements in submaximal exercise capacity only, whereas recreational grass football training confirmed previous positive effects on submaximal exercise capacity as well as cardiorespiratory fitness

Effects of 3 months of full-court and half-court street basketball training on health profile in untrained men

Purpose: The aim of the present study was to investigate whether street basketball organized as 3 v 3 on either a half court (HC) with 1 basket or a full court (FC) with 2 baskets could improve fitness and health profiles of untrained men after 3 months of supervised training. Methods: Thirty-five untrained men (aged 20–42 years) completed the pre- and post-intervention testing (FC: n = 13, HC: n = 12, CO (control): n = 10). The training attendance was 2.0 ± 0.4 and 1.9 ± 0.3 times per week in FC and HC, respectively. Mean heart rate (HR) was 83.8 ± 6.0 percent of maximal heart rate (%HRmax) and 84.5 ± 2.9 %HRmax in FC and HC, respectively. Results: The 3 months of street basketball training on an FC with 2 baskets increased maximal oxygen uptake (2.4 mL/min/kg (95% confidence interval (CI): 1.0–3.9)), time to exhaustion (47 s (95%CI: 26–67)), lean body mass (0.8 kg (95%CI: 0.1–1.5)), and bone mineral density (0.021 g/cm2 (95%CI: 0.011–0.031)), whereas mean arterial pressure (–5.6 mmHg (95%CI: –7.5 to 3.7)), body fat percentage (–1.6%, (95%CI: –2.5 to –0.7)), heart rate (–18 bpm (95%CI: –24 to –12)), and blood lactate (median: –1.4 mmol/L (interquartile range: –1.5 to –0.6)) during submaximal running were lowered. The changes were less pronounced after the training period when playing on an HC with 1 basket, but increases in maximal oxygen uptake (1.6 mL/min/kg (95%CI: –0.1 to 3.3)), time to exhaustion (28 s (95%CI: 9–47)), lean body mass (1.3 kg (95%CI: 0.3–2.4)), and lower body fat percentage (–0.9% (95%CI: –1.9 to –0.1)) were observed in this group. Conclusion: Three months of 3 v 3 street basketball training improved fitness and led to broad-spectrum improvements in variables related to overall health profile, with the most marked effects observed when playing on an FC with 2 baskets. Keywords: Blood pressure, Body composition, Cardiovascular fitness, Maximal oxygen uptake, Muscoloskeletal fitness, Physical demands, Small-sided games, Team spor

Impact of the gate geometry on adiabatic charge pumping in InAs double quantum dots

We compare the adiabatic quantized charge pumping performed in two types of InAs nanowire double quantum dots (DQDs), either with tunnel barriers defined by closely spaced narrow bottom gates, or by well-separated side gates. In the device with an array of bottom gates of 100 nm pitch and 10 mu m lengths, the pump current is quantized only up to frequencies of a few MHz due to the strong capacitive coupling between the bottom gates. In contrast, in devices with well-separated side gates with reduced mutual gate capacitances, we find well-defined pump currents up to 30 MHz. Our experiments demonstrate that high frequency quantized charge pumping requires careful optimization of the device geometry, including the typically neglected gate feed lines

Who gets the ventilator? A multicentre survey of intensivists' opinions of triage during the first wave of the COVID-19 pandemic

Background The COVID-19 pandemic has caused a shortage of intensive care resources. Intensivists' opinion of triage and ventilator allocation during the COVID-19 pandemic is not well described. Methods This was a survey concerning patient numbers, bed capacity, triage guidelines, and three virtual cases involving ventilator allocations. Physicians from 400 ICUs in a research network were invited to participate. Preferences were assessed with a five-point Likert scale. Additionally, age, gender, work experience, geography, and religion were recorded. Results Of 437 responders 31% were female. The mean age was 44.4 (SD 11.1) with a mean ICU experience of 13.7 (SD 10.5) years. Respondents were mostly European (88%). Sixty-six percent had triage guidelines available. Younger patients and caretakers of children were favoured for ventilator allocation although this was less clear if this involved withdrawal of the ventilator from another patient. Decisions did not differ with ICU experience, gender, religion, or guideline availability. Consultation of colleagues or an ethical committee decreased with age and male gender. Conclusion Intensivists appeared to prioritise younger patients for ventilator allocation. The tendency to consult colleagues about triage decreased with age and male gender. Many found such tasks to be not purely medical and that authorities should assume responsibility for triage during resource scarcity.publishedVersio

Consent is a confounding factor in a prospective observational study of critically ill elderly patients.

During analysis of a prospective multinational observation study of critically ill patients ≥80 years of age, the VIP2 study, we also studied the effects of differences in country consent for study inclusion. This is a post hoc analysis where the ICUs were analyzed according to requirement for study consent. Group A: ICUs in countries with no requirement for consent at admission but with deferred consent in survivors. Group B: ICUs where some form of active consent at admission was necessary either from the patient or surrogates. Patients' characteristics, the severity of disease and outcome variables were compared. Totally 3098 patients were included from 21 countries. The median age was 84 years (IQR 81-87). England was not included because of changing criteria for consent during the study period. Group A (7 countries, 1200 patients), and group B (15 countries, 1898 patients) were comparable with age and gender distribution. Cognition was better preserved prior to admission in group B. Group A suffered from more organ dysfunction at admission compared to group B with Sequential Organ Failure Assessment score median 8 and 6 respectively. ICU survival was lower in group A, 66.2% compared to 78.4% in group B (p<0.001). We hence found profound effects on outcomes according to differences in obtaining consent for this study. It seems that the most severely ill elderly patients were less often recruited to the study in group B. Hence the outcome measured as survival was higher in this group. We therefore conclude that consent likely is an important confounding factor for outcome evaluation in international studies focusing on old patients