The lattice Landau gauge gluon propagator: lattice spacing and volume dependence

The interplay between the finite volume and finite lattice spacing is investigated using lattice QCD simulations to compute the Landau gauge gluon propagator. Comparing several ensembles with different lattice spacings and physical volumes, we conclude that the dominant effects, in the infrared region, are associated with the use of a finite lattice spacing. The simulations show that decreasing the lattice spacing, while keeping the same physical volume, leads to an enhancement of the infrared gluon propagator. In this sense, the data from $\beta=5.7$ simulations, which uses an $a \approx 0.18$ fm, provides a lower bound for the infinite volume propagator.Comment: Final version to appear in Phys Rev

Learning roadmaps for Higher Education

An integrated platform for the support of teaching activities as been developed and deployed at the Aveiro Norte Polytechnic School of the University of Aveiro. In this paper we present an approach to Learning Roadmaps for Higher Education based on this platform. The aprend.e platform – Electronic Integrated System for Learning and Training - has at its core a Learning Management System with a number of plugins. It represents a new challenge for the University of Aveiro for higher education and is already being at its core is the concept of learning roadmaps that act upon two fundamental axes: education and learning. For the teachers, it aims at becoming a self-supporting tool that stimulates the organization and management of the course materials (lectures, presentations, multimedia content, and evaluation materials, amongst others). For the students, the learning roadmap aims at promoting self-study and supervised study, endowing the pupil with the capabilities to find the relevant information and to capture the concepts in the study materials. The outcome will be a stimulating learning process together with an organized management of those materials

Analysis domain model for shared virtual environments

The field of shared virtual environments, which also encompasses online games and social 3D environments, has a system landscape consisting of multiple solutions that share great functional overlap. However, there is little system interoperability between the different solutions. A shared virtual environment has an associated problem domain that is highly complex raising difficult challenges to the development process, starting with the architectural design of the underlying system. This paper has two main contributions. The first contribution is a broad domain analysis of shared virtual environments, which enables developers to have a better understanding of the whole rather than the part(s). The second contribution is a reference domain model for discussing and describing solutions - the Analysis Domain Model

Lactobacillus crispatus as the etiological agent in cytolytic vaginosis

Introduction: Lactobacillus spp. dominate the vaginal niche but can also be involved in other vaginal dysbiosis, such as cytolytic vaginosis (CV), which remains poorly studied. It is characterized by a cryptic symptomatology, that often confounds the clinic. Goals: The aim of this work was to search for the etiological agent of CV, by studying the vaginal microbiome and metabolomics of women afflicted with this disease and compare it with women with other clinical diagnostic. Methods: Twenty-one vaginal washes have been collected from women attending a gynaecology consultation of a private clinic. The samples were categorized according with clinical diagnosis at the time of sampling (CV, 11; vulvovaginal candidosis, 8; Healthy, 2). The distribution of bacterial species, and their prevalence was assessed by next-generation sequencing of the 16S V4 region. In addition, total lactate D-lactic acid and L-lactic acid was quantified in all washes by a commercial kit, as well as lactate dehydrogenase (LDH) activity. Results: L. crispatus was dominant (>70%) in all CV samples. Lactate was increased in CV in comparison with other cases. The presence of D-lactic acid isomer was associated with presence of L. crispatus. LDH activity was increased in vaginal washes that tested positive for the presence of L. crispatus, however no direct association was found with CV cases. Discussion/Conclusions: The microbiome of women afflicted with CV was dominated in all cases by L. crispatus, contrarily with the results obtained for women diagnosed with other clinical symptomatology. In addition, the finding that an increase in D-lactic acid is associated with CV patients can be related to the role of L. crispatus in CV. The determination of LDH activity did not correlate exclusively with CV cases. On the other hand, D-lactic acid and total lactate quantification could be used as a valuable biomarker to diagnose this cryptic vaginal infection.info:eu-repo/semantics/publishedVersio

Fracturing the optimal paths

Optimal paths play a fundamental role in numerous physical applications ranging from random polymers to brittle fracture, from the flow through porous media to information propagation. Here for the first time we explore the path that is activated once this optimal path fails and what happens when this new path also fails and so on, until the system is completely disconnected. In fact numerous applications can be found for this novel fracture problem. In the limit of strong disorder, our results show that all the cracks are located on a single self-similar connected line of fractal dimension $D_{b} \approx 1.22$. For weak disorder, the number of cracks spreads all over the entire network before global connectivity is lost. Strikingly, the disconnecting path (backbone) is, however, completely independent on the disorder.Comment: 4 pages,4 figure

Newtonian Perturbations on Models with Matter Creation

Creation of Cold Dark Matter (CCDM) can macroscopically be described by a negative pressure, and, therefore, the mechanism is capable to accelerate the Universe, without the need of an additional dark energy component. In this framework we discuss the evolution of perturbations by considering a Neo-Newtonian approach where, unlike in the standard Newtonian cosmology, the fluid pressure is taken into account even in the homogeneous and isotropic background equations (Lima, Zanchin and Brandenberger, MNRAS {\bf 291}, L1, 1997). The evolution of the density contrast is calculated in the linear approximation and compared to the one predicted by the $\Lambda$CDM model. The difference between the CCDM and $\Lambda$CDM predictions at the perturbative level is quantified by using three different statistical methods, namely: a simple $\chi^{2}$-analysis in the relevant space parameter, a Bayesian statistical inference, and, finally, a Kolmogorov-Smirnov test. We find that under certain circumstances the CCDM scenario analysed here predicts an overall dynamics (including Hubble flow and matter fluctuation field) which fully recovers that of the traditional cosmic concordance model. Our basic conclusion is that such a reduction of the dark sector provides a viable alternative description to the accelerating $\Lambda$CDM cosmology.Comment: Physical Review D in press, 10 pages, 4 figure

Assessment of Lactobacillus crispatus´ role in vaginal infections: friend or foe?

Lactobacillus spp. are the most prevalent microorganisms in the vaginal milleu. Several probiotic mechanisms have been associated with Lactobacillus, but the most relevant one is lactate production – resulting in a low pH value, typical of the healthy vagina. However, its pathogenic state is still unknown. We aim to elucidate the role of a commensal vaginal microorganism, Lactobacillus crispatus, in vaginal infections. Twenty-four vaginal washes have been collected from women attending a gynaecology consultation of a private clinic. The samples were categorized according with clinical diagnosis at the time of sampling. The distribution of bacterial species, and their prevalence was assessed by Next-Generation Sequencing of the 16S rRNA V4 region. In addition, L- and D-lactate concentration, and LDH enzymatic activity was quantified in all washes by a commercial kit. Detection of Candida spp. was performed by PCR. L. crispatus was dominant (>70%) in 11 out of 24 samples – diagnosed for vaginal atrophy (VA, 3), cytolytic vaginosis (CV, 2) and lactobacillosis (LB, 2). Lactate was increased in CV, LB and VA cases only. The remaining samples, diagnosed for vulvovaginal candidosis in its majority, had lower prevalence of L. crispatus; and lower to moderate lactate metabolite. There was not a direct relationship between LDH enzymatic activity and clinical diagnosis. L. crispatus dominance, associated with increased lactate production, was observed in CV, LB and VA cases. These results indicate that this microorganism might have a role in dysbiosis of the vagina associated with these specific pathologies.info:eu-repo/semantics/publishedVersio

Role of Lactobacillus crispatus in vaginal infections: insights from metagenomics and metabolomics studies

Objective: Lactobacillus spp. constitute the most prevalent bacterial microorganism in the vaginal milleu. Several probiotic mechanisms have been associated with Lactobacillus, but the most relevant one is lactate production – resulting in a low pH value, typical of the healthy vagina. We aim to elucidate the role of a native vaginal microorganism, Lactobacillus crispatus, in vaginal infections. Methods: Twenty-four vaginal washes have been collected from women (mean 38±14 years of age) attending a gynecology consultation of a private clinic. The samples were categorized according with clinical diagnosis at the time of sampling. The distribution of bacterial species, and their prevalence was assessed by next-generation sequencing of the 16S V4 region. In addition, lactate was quantified in all washes by a commercial kit. Results: L. crispatus was dominant (>70%) in 11 out of 24 samples – diagnosed for vaginal atrophy (VA, 3), cytolytic vaginosis (CV, 2), lactobacillosis (LB, 2) and vulvovaginal candidosis (VVC, 1). For three samples, diagnostic was inconclusive. Lactate was increased in CV, LB and VA cases only. One sample, diagnosed with VVC had 23% dominance of L. crispatus; and lower lactate metabolite. L. crispatus was not detected in the remaining 12 cases (6 VVC, 4 VA, 1 healthy and 1 inconclusive). Of these, only 5 samples had moderate lactate metabolite. Conclusions: L. crispatus dominance, associated with increased lactate production, was observed in CV, LB and VA cases. These results indicate that this microorganism might have a role in dysbiosis of the vagina associated with these specific pathologies.info:eu-repo/semantics/publishedVersio

Roughness exponents and grain shapes

In surfaces with grainy features, the local roughness $w$ shows a crossover at a characteristic length $r_c$, with roughness exponent changing from $\alpha_1\approx 1$ to a smaller $\alpha_2$. The grain shape, the choice of $w$ or height-height correlation function (HHCF) $C$, and the procedure to calculate root mean-square averages are shown to have remarkable effects on $\alpha_1$. With grains of pyramidal shape, $\alpha_1$ can be as low as 0.71, which is much lower than the previous prediction 0.85 for rounded grains. The same crossover is observed in the HHCF, but with initial exponent $\chi_1\approx 0.5$ for flat grains, while for some conical grains it may increase to $\chi_1\approx 0.7$. The universality class of the growth process determines the exponents $\alpha_2=\chi_2$ after the crossover, but has no effect on the initial exponents $\alpha_1$ and $\chi_1$, supporting the geometric interpretation of their values. For all grain shapes and different definitions of surface roughness or HHCF, we still observe that the crossover length $r_c$ is an accurate estimate of the grain size. The exponents obtained in several recent experimental works on different materials are explained by those models, with some surface images qualitatively similar to our model films.Comment: 7 pages, 6 figures and 2 table