Exponentially Localized Magnetic Fields for Single-Spin Quantum Logic Gates

An infinite array of parallel current-carrying wires is known, from the field of neutral particle optics, to produce an exponentially localized magnetic field when the current direction is antiparallel in adjacent wires. We show that a finite array of several tens of superconducting Nb nanowires can produce a peak magnetic field of 10mT that decays by a factor of 10^4 over a length scale of 500nm. Such an array is readily manufacturable with current technology, and is compatible with both semiconductor and superconducting quantum computer architectures. A series of such arrays can be used to individually address single single-spin or flux qubits spaced as little as 100nm apart, and can lead to quantum logic gate times of 5ns.Comment: 5 pages, incl. 4 figure

Variação genética de uma população natural de Araucaria angustifolia (Bert) O. Ktze.

Resumo

Endogenous Cycles in Optimal Monetary Policy with a Nonlinear Phillips Curve

There is by now a large consensus in modern monetary policy. This consensus has been built upon a dynamic general equilibrium model of optimal monetary policy with sticky prices a la Calvo and forward looking behavior. In this paper we extend this standard model by introducing nonlinearity into the Phillips curve. As the linear Phillips curve may be questioned on theoretical grounds and seems not to be favoured by empirical evidence, a similar procedure has already been undertaken in a series papers over the last few years, e.g., Schaling (1999), Semmler and Zhang (2004), Nobay and Peel (2000), Tambakis (1999), and Dolado et al. (2004). However, these papers were mainly concerned with the analysis of the problem of inflation bias, by deriving an interest rate rule which is nonlinear, leaving the issues of stability and the possible existence of endogenous cycles in such a framework mostly overlooked. Under the specific form of nonlinearity proposed in our paper (which allows for both convexity and concavity and secures closed form solutions), we show that the introduction of a nonlinear Phillips curve into a fully deterministic structure of the standard model produces significant changes to the major conclusions regarding stability and the efficiency of monetary policy in the standard model. We should emphasize the following main results: (i) instead of a unique fixed point we end up with multiple equilibria; (ii) instead of saddle--path stability, for different sets of parameter values we may have saddle stability, totally unstable and chaotic fixed points (endogenous cycles); (iii) for certain degrees of convexity and/or concavity of the Phillips curve, where endogenous fluctuations arise, one is able to encounter various results that seem interesting. Firstly, when the Central Bank pays attention essentially to inflation targeting, the inflation rate may have a lower mean and is certainly less volatile; secondly, for changes in the degree of price stickiness the results are not are clear cut as in the previous case, however, we can also observe that when such stickiness is high the inflation rate tends to display a somewhat larger mean and also higher volatility; and thirdly, it shows that the target values for inflation and the output gap (π^,x^), both crucially affect the dynamics of the economy in terms of average values and volatility of the endogenous variables --- e.g., the higher the target value of the output gap chosen by the Central Bank, the higher is the inflation rate and its volatility --- while in the linear case only the π^ does so (obviously, only affecting in this case the level of the endogenous variables). Moreover, the existence of endogenous cycles due to chaotic motion may raise serious questions about whether the old dictum of monetary policy (that the Central Bank should conduct policy with discretion instead of commitment) is not still very much in the business of monetary policy.Optimal monetary policy, Interest Rate Rules, Nonlinear Phillips Curve, Endogenous Fluctuations and Stabilization

Mapping the educational and career paths of youth workers

info:eu-repo/semantics/publishedVersio

Performance Gap Between Men and Women in Ironman Triathlons

PURPOSE: The increased participation and performance improvement of women in Ironman triathlons (IM) have been showing that the performance gap with men is shorter than ever. Thus, this study aimed to explore this performance gap by discipline (swimming, cycling, and running) and age-groups. METHODS: Publicly available data from all IM events from 2002 to 2022 were used for this analysis. Each performance variable (swimming, cycling, running, and overall) were included as dependent variables in general linear model with gender and category (elite, age-groups) as independent factors. The effect size (Cohen’s d and delta percentage) was calculated for every “male vs. female” comparison. RESULTS: A total of 741,973 entries were analyzed (women=145,008; men=596,965) and 12,670 of those were categorized as elite. For elite athletes, the running portion presented the smallest performance gap (7.3%, d = 0.432), whereas cycling and swimming showed a similar gap (swim: 10.7%, d=0.676; cycle: 10.0%, d = 1.132). For age-groupers, the largest gap was cycling (7.87%, d =0.633). In addition, age-groupers between 30 and 49 years showed the largest performance gap (7.9% - 8.0%), when compared to younger (old) or older (\u3e49 years old) athletes (5.0 – 6.9%). CONCLUSION: Overall, men consistently outperform women in all three disciplines of IM. However, the performance gap varies based on age group, level, and discipline. While elite athletes have small performance gaps in running, age-groupers have their largest performance gap in cycling. Additionally, age-groupers within 30-49 years of age have the largest performance gap amongst amateur athletes in IM

Two-dimensional quantum spin-1/2 Heisenberg model with competing interactions

We study the quantum spin-1/2 Heisenberg model in two dimensions, interacting through a nearest-neighbor antiferromagnetic exchange ($J$) and a ferromagnetic dipolar-like interaction ($J_d$), using double-time Green's function, decoupled within the random phase approximation (RPA). We obtain the dependence of $k_B T_c/J_d$ as a function of frustration parameter $\delta$, where $T_c$ is the ferromagnetic (F) transition temperature and $\delta$ is the ratio between the strengths of the exchange and dipolar interaction (i.e., $\delta = J/J_d$). The transition temperature between the F and paramagnetic phases decreases with $\delta$, as expected, but goes to zero at a finite value of this parameter, namely $\delta = \delta_c = \pi /8$. At T=0 (quantum phase transition), we analyze the critical parameter $\delta_c(p)$ for the general case of an exchange interaction in the form $J_{ij}=J_d/r_{ij}^{p}$, where ferromagnetic and antiferromagnetic phases are present.Comment: 4 pages, 1 figur

Relación entre el índice de masa corporal con la ingesta de fibra dietética y pliegues de la piel; las diferencias entre los culturistas que se entrenan durante el período de la mañana y nocturno

The prevalence of overweight individuals has increased in recent years. Moreover, the importance of a healthy diet is associated with the practice of physical activity and attempt to verify the achievement of physical exercise influences on food choice. However, it relationship between food intake and physical activity have not been studied. To evaluate if the period in which the trainings are conducted, morning and nocturne, interfere qualitatively and quantitatively in food consumption as well as verify possible associations between anthropometric profiles and dietary habits. We collected data from 33 adult volunteers, between men and women, practitioners of bodybuilding. A total of 33 volunteers were interviewed (18 (54.5%) were men and 15 (45.5%) were women). Regarding anthropometric data, it turns out that that the volunteers of the two periods had similar characteristics, differentiating only weight. The consumption of nutritional supplements was observed in 30.77% of the practitioners in the morning period vs. 35% for the nocturne. Considering macronutrient intake, there was a significant difference in the consumption of protein between the periods. The consumption during nocturne period was greater (126 ± 5% of the daily requirement) than the morning period (115.7 ± 2%). As for micro-nutrients, calcium intake was greater among men when compared to women. There was a positive correlation between the BMI, and arm circumference for practitioners of the morning period. This study show that the practitioners who train in the morning have quietly better eating habits than those in the nocturne period, however both are inappropriate.273929935La prevalencia de individuos con sobrepeso ha aumentado en los últimos años. Además, la importancia de una dieta saludable se asocia con la práctica de actividad física y los intentos de lograr la realización de la esta actividad influyen en la elección de la dieta. Sin embargo, la relación entre la ingesta dietética y la actividad física no se ha estudiado. Evaluar si el periodo en que se realiza el entrenamiento, diurno y nocturno, interfiere cualitativa y cuantitativamente en el consumo de alimentos, así como comprobar posibles asociaciones entre los perfiles antropométricos y los hábitos dietéticos. Recogimos los datos de 33 adultos voluntarios, hombres y mujeres, culturistas. Se entrevistó a un total de 33 voluntarios (18 (54,5%) hombres y 15 (45,5%) mujeres). Con respecto a los datos antropométricos, los voluntarios de ambos periodos tenían características similares, diferenciándose sólo por el peso. El consumo de suplementos nutritivos se observó en el 30,77% de los culturistas de la mañana frente al 35% de los de la noche. Con respecto al consumo de macronutrientes, hubo una diferencia significativa en el consumo de proteínas entre ambos periodos. El consumo durante el periodo de la noche fue mayor (126 ± 5% de las necesidades diarias) que el de la mañana (115,7 ± 2%). Para los micronutrientes, el consumo de calcio fue superior entre los hombres en comparación con las mujeres. Hubo una correlación positiva entre el IMC y la circunferencia del brazo en los culturistas de la mañana. Este estudio demuestra que los culturistas que se entrenan durante el día tienen hábitos dietéticos más saludables que aquellos que lo hacen por la noche, aunque en ambos son inapropiado

Variação genética em progênies de segunda geração de Araucaria angustifolia Bert. O. Ktze.

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Efeito de diferentes solventes orgânicos sobre a viabilidade do pólen de jerivá (Syagrus romanzoffiana S. CHAM).

EVINCI. Resumo