Jarlskog-like invariants for theories with scalars and fermions

Within the framework of theories where both scalars and fermions are present, we develop a systematic prescription for the construction of CP-violating quantities that are invariant under basis transformations of those matter fields. In theories with Spontaneous Symmetry Breaking, the analysis involves the vevs' transformation properties under a scalar basis change, with a considerable simplification of the study of CP violation in the scalar sector. These techniques are then applied in detail to the two Higgs-doublet model with quarks. It is shown that there are new invariants involving scalar-fermion interactions, besides those already derived in previous analyses for the fermion-gauge and scalar-gauge sectors.Comment: 12 pages, Latex, no figure

Numerical simulation study of the dynamical behavior of the Niedermayer algorithm

We calculate the dynamic critical exponent for the Niedermayer algorithm applied to the two-dimensional Ising and XY models, for various values of the free parameter $E_0$. For $E_0=-1$ we regain the Metropolis algorithm and for $E_0=1$ we regain the Wolff algorithm. For $-1<E_0<1$, we show that the mean size of the clusters of (possibly) turned spins initially grows with the linear size of the lattice, $L$, but eventually saturates at a given lattice size $\widetilde{L}$, which depends on $E_0$. For $L>\widetilde{L}$, the Niedermayer algorithm is equivalent to the Metropolis one, i.e, they have the same dynamic exponent. For $E_0>1$, the autocorrelation time is always greater than for $E_0=1$ (Wolff) and, more important, it also grows faster than a power of $L$. Therefore, we show that the best choice of cluster algorithm is the Wolff one, when compared to the Nierdermayer generalization. We also obtain the dynamic behavior of the Wolff algorithm: although not conclusive, we propose a scaling law for the dependence of the autocorrelation time on $L$.Comment: Accepted for publication in Journal of Statistical Mechanics: Theory and Experimen

Erros em esquemas de demonstração com números complexos

As produções escritas de estudantes podem ser objeto de análise com vista à investigação e ao ensino. Neste trabalho, um dos poucos sobre erros e números complexos, analisam- se as produções, elaboradas por estudantes do ensino superior, para uma tarefa de demonstração de um caso particular da identidade do paralelogramo. Num trabalho que pode dar pistas para a prática letiva de professores do ensino secundário e do ensino superior, procura-se classificar os esquemas de demonstração nessas produções, identificar os erros neles cometidos e relacionar estas duas vertentes de análise. A natureza da investigação é qualitativa, recorrendo à análise de conteúdo empregando, por um lado, critérios prévios de categorizações de esquemas de demonstração e, por outro, critérios novos de categorizações de erros. Constatou-se que os estudantes utilizaram, principalmente, esquemas de demonstração de convicção externa, incluídos numa subcategoria nova designada por não válidos no universo, e esquemas de demonstração dedutivos, incluídos num nível novo que se caracteriza por discernimento incipiente da compreensão da tarefa, do contexto matemático, de hipóteses e tese, e dos conhecimentos prévios a mobilizar. Os erros dominantes nas produções estão relacionados à compreensão dos conceitos de linearidade de uma função e de módulo de um número complexo, apresentando-se possíveis explicações para os mesmos. Apesar de não se identificar uma relação propriamente significativa entre os esquemas de demonstração produzidos pelos estudantes e os erros cometidos, obteve-se material para construção e discussão de questões conceituais no âmbito do tópico números complexos.info:eu-repo/semantics/publishedVersio

Dynamical behavior of the Niedermayer algorithm applied to Potts models

In this work we make a numerical study of the dynamic universality class of the Niedermayer algorithm applied to the two-dimensional Potts model with 2, 3, and 4 states. This algorithm updates clusters of spins and has a free parameter, $E_0$, which controls the size of these clusters, such that $E_0=1$ is the Metropolis algorithm and $E_0=0$ regains the Wolff algorithm, for the Potts model. For $-1<E_0<0$, only clusters of equal spins can be formed: we show that the mean size of the clusters of (possibly) turned spins initially grows with the linear size of the lattice, $L$, but eventually saturates at a given lattice size $\widetilde{L}$, which depends on $E_0$. For $L \geq \widetilde{L}$, the Niedermayer algorithm is in the same dynamic universality class of the Metropolis one, i.e, they have the same dynamic exponent. For $E_0>0$, spins in different states may be added to the cluster but the dynamic behavior is less efficient than for the Wolff algorithm ($E_0=0$). Therefore, our results show that the Wolff algorithm is the best choice for Potts models, when compared to the Niedermayer's generalization.Comment: 10 pages, 11 figures, to be published in Physica A. arXiv admin note: substantial text overlap with arXiv:1003.365

The Role of Hyperbaric Oxygen Therapy in Pneumatosis Cystoides Intestinalis—A Scoping Review

Pneumatosis cystoides intestinalis (PCI) is characterized by gas-filled cysts within gastrointestinal tract wall from esophagus to rectum, with preferential involvement of large and small intestine. PCI is rare with an estimated incidence of 0.03 to 0-2% in general population. PCI can be distinguished into idiopathic (15%) or secondary (85%) and the clinical picture ranges from completely asymptomatic to life-threatening intraabdominal complications. Although etiology of PCI appears to be multifactorial, the exact pathophysiology is poorly understood and two main theories have been proposed (mechanical and bacterial). Over the last decades, an enormous therapeutic armamentarium was considered in PCI's management, including hyperbaric oxygen therapy (HBOT). Treatment comprises conservative treatment in mild cases to surgery in highly symptomatic and complicated PCI. In the late 70s, HBOT started to be used in selected cases of PCI not responding to conservative measures. Since then, several case reports, case series, and reviews have been published in the literature with variable outcomes. The overall response rate and complete response were 92.1% (n = 82/89) and 65.2% (n = 58/89), respectively, with a median follow-up of 7 months. Furthermore, HBOT is extremely safe, with few reported complications in the literature when used for PCI. Nevertheless, a randomized, controlled, and double-blind clinical trial is unlikely to occur given the rarity of PCI, logistical issues of HBOT, and methodological considerations related to adequate blinding with a sham-controlled group. HBOT in combination with personalized diet and antibiotics may be beneficial for moderate to severe PCI in patients with no indication for emergency exploratory laparotomy. The purpose of this article is to synthesize the existing data, analyse results of previous studies, identify gaps in knowledge, and discuss PCI' management, including the proposal of an algorithm, with a special focus on HBOT.info:eu-repo/semantics/publishedVersio

Abelian symmetries in multi-Higgs-doublet models

N-Higgs doublet models (NHDM) are a popular framework to construct electroweak symmetry breaking mechanisms beyond the Standard model. Usually, one builds an NHDM scalar sector which is invariant under a certain symmetry group. Although several such groups have been used, no general analysis of symmetries possible in the NHDM scalar sector exists. Here, we make the first step towards this goal by classifying the elementary building blocks, namely the abelian symmetry groups, with a special emphasis on finite groups. We describe a strategy that identifies all abelian groups which are realizable as symmetry groups of the NHDM Higgs potential. We consider both the groups of Higgs-family transformations only and the groups which also contain generalized CP transformations. We illustrate this strategy with the examples of 3HDM and 4HDM and prove several statements for arbitrary N.Comment: 33 pages, 2 figures; v2: conjecture 3 is proved and becomes theorem 3, more explanations of the main strategy are added, matches the published versio

Mice learn multi-step routes by memorizing subgoal locations

The behavioral strategies that mammals use to learn multi-step routes are unknown. In this study, we investigated how mice navigate to shelter in response to threats when the direct path is blocked. Initially, they fled toward the shelter and negotiated obstacles using sensory cues. Within 20 min, they spontaneously adopted a subgoal strategy, initiating escapes by running directly to the obstacle’s edge. Mice continued to escape in this manner even after the obstacle had been removed, indicating use of spatial memory. However, standard models of spatial learning—habitual movement repetition and internal map building—did not explain how subgoal memories formed. Instead, mice used a hybrid approach: memorizing salient locations encountered during spontaneous ‘practice runs’ to the shelter. This strategy was also used during a geometrically identical food-seeking task. These results suggest that subgoal memorization is a fundamental strategy by which rodents learn efficient multi-step routes in new environments

Comparative Analysis of Fatigue Life Predictions in Lateral Notched Round Bars under Multiaxial Loading

The main objective of this study is to predict the multiaxial fatigue life for lateral notched round bars made of DIN 34CrNiMo6 high strength steel. In-phase bending-torsion tests for different stress amplitudes and different ratios of the normal stress to the shear stress were performed. Single torsion and single bending tests were also conducted for different stress amplitudes. In addition, the beach marking technique was used to mark crack fronts on fracture surfaces for the different loading paths studied. Experimental fatigue life was compared with predictions obtained by the Coffin-Manson model. The stress-strain state at the notch root was evaluated using the Theory of Critical Distances (TCD) and the Equivalent Strain Energy Density (ESED). Finally, a comparative analysis of the fatigue life predictions obtained by the two above-mentioned approaches was carried out. The former gave good results for higher lives but was too conservative for lower lives. The latter led to good correlations in the range studied here

DESIGN AND STUDY OF DIMENSIONAL PARAMETERS INFLUENCE ON VORTEX TUBE BEHAVIOR

Vortex tube is a thermodynamic device, with no moving parts, applied to separate hot and cold air from compressed air injected into the tube. It has many applications in the industry, for example, among others, it can be mentioned electronic systems cooling, machining processes cooling and environmental chambers. This paper presents the design and tube dimensioning based on parameters and data found in the literature. Therefore, a prototype has been made and tested, which allowed the understanding of the influence of internal tube diameter and width on the hot and cold air temperatures while submitted to compressed air with pressure varying from 1 to 2.5bar. Results of tested configurations indicates that the relation between tube length and diameter (L/D) has small influence on vertex tube behavior, meanwhile, 3/8” tube diameter shows lowest temperatures on cold flow (-6.5°C, -8.0°C and -8.5°C) and higher COP (≈ 0.15)

ATLAS Logical File Name and Directory Path Convention

The convention to form logical files entries in file's catalog used by ATLA