Menière’s Disease: Etiopathogenesis

This chapter will discuss idiopathic Menière’s syndrome. That is to say—Menière’s disease. We will start with a brief recall on the History of Menière’s disease beginning with the description of the syndrome by Prosper Menière in 1861, the description of endolymphatic hydrops in temporal bone studies by Hallpike and Cairns in 1938 and by Yamakaua in the same year. Endolymphatic hydrops became a pathologic correlate for Menière’s syndrome. Theories that considered endolymphatic hydrops as the cause of the syndrome will be discussed. More recent studies questioning the old theories and thinking of endolymphatic hydrops as an epiphenomenon in the course of the syndrome rather than the cause of the symptoms will be discussed. Temporal bone studies were the basis of these new theories too. Familial Menière’s disease will be discussed and several families will be described in detail. Because the phenotype of siblings on each family studied was variable and migraine was present in many affected members of these families a spectrum was postulated going from migraine alone to full blown Menière’s disease. Some siblings had what has been described recently as vertiginous migraine and a detailed description of this syndrome will be provided and the differences between this syndrome and Menière’s disease will be made clear. About 20% of Menière’s disease patients have a familial history. Sporadic Meniere’s disease might have a genetic predisposition and other environmental and behavioral factors contribute for the surfacing of the disease (multifactorial etiology). Because migraine is a central phenomenon and the vertiginous episodes and auditory symptoms are peripheral a hypothesis is presented for the pathophysiology of Menière’s disease. Recent research comparing vestibular migraine and Manière’s disease reinforcing the concept of these syndromes representing a continuum process with similar etiology are discussed at the end

The Likelihood Ratio Test and Full Bayesian Significance Test under small sample sizes for contingency tables

Hypothesis testing in contingency tables is usually based on asymptotic results, thereby restricting its proper use to large samples. To study these tests in small samples, we consider the likelihood ratio test and define an accurate index, the P-value, for the celebrated hypotheses of homogeneity, independence, and Hardy-Weinberg equilibrium. The aim is to understand the use of the asymptotic results of the frequentist Likelihood Ratio Test and the Bayesian FBST -- Full Bayesian Significance Test -- under small-sample scenarios. The proposed exact P-value is used as a benchmark to understand the other indices. We perform analysis in different scenarios, considering different sample sizes and different table dimensions. The exact Fisher test for $2 \times 2$ tables that drastically reduces the sample space is also discussed. The main message of this paper is that all indices have very similar behavior, so the tests based on asymptotic results are very good to be used in any circumstance, even with small sample sizes

The Highest Geomagnetic Storms of the Solar Cycle Observed at Ground Level

We report two ground-level observations, of geomagnetic storms of different origins; they are among the highest geomagnetic storms, in the solar Cycle 24. The first is St. Patrick’s Day storm on March 17, 2015, originated by the impact on Earth’s atmosphere of coronal mass ejections (CMEs), the storm reaching the condition of G4 (severe) level, in the NOAA geomagnetic scale. The second included the major geomagnetic storm whose origin is attributed to the interaction with the Earth of a High-Speed Stream (HSS) ahead of a positive polarity coronal hole on October 7, 2015. This storm reached the condition G3 (strong) level. We give emphasis to observations detected by the New-Tupi muon telescopes, located at sea level in Brazil (22.53° S, 43.13° W). We present a study of these observations in correlation with observations reported by multipoint space-based measurements, such as the ACE at Lagrange Point L1 and the geostationary GOES weather satellite, including two global geomagnetic indices and several ground-based detectors. Some considerations on the influence of these geomagnetic storms in the Earth weather are reported

Near-Exact Distributions for Likelihood Ratio Statistics Used in the Simultaneous Test of Conditions on Mean Vectors and Patterns of Covariance Matrices

The authors address likelihood ratio statistics used to test simultaneously conditions on mean vectors and patterns on covariance matrices. Tests for conditions on mean vectors, assuming or not a given structure for the covariance matrix, are quite common, since they may be easily implemented. But, on the other hand, the practical use of simultaneous tests for conditions on the mean vectors and a given pattern for the covariance matrix is usually hindered by the nonmanageability of the expressions for their exact distribution functions. The authors show the importance of being able to adequately factorize the c.f. of the logarithm of likelihood ratio statistics in order to obtain sharp and highly manageable near-exact distributions, or even the exact distribution in a highly manageable form. The tests considered are the simultaneous tests of equality or nullity of means and circularity, compound symmetry, or sphericity of the covariance matrix. Numerical studies show the high accuracy of the near-exact distributions and their adequacy for cases with very small samples and/or large number of variables. The exact and near-exact quantiles computed show how the common chi-square asymptotic approximation is highly inadequate for situations with small samples or large number of variables

Electromagnetic dual Einstein-Maxwell-scalar models

Electromagnetic duality is discussed in the context of Einstein-Maxwell-scalar (EMS) models including axionic-type couplings. This family of models introduces two non-minimal coupling functions $f(\phi)$ and $g(\phi)$, depending on a real scalar field $\phi$. Interpreting the scalar field as a medium, one naturally defines constitutive relations as in relativistic non-linear electrodynamics. Requiring these constitutive relations to be invariant under the $SO(2)$ electromagnetic duality rotations of Maxwell's theory, defines 1-parameter, closed $\textit{duality orbits}$ in the space of EMS models, connecting different electromagnetic fields in "dual" models with different coupling functions, but leaving both the scalar field and the spacetime geometry invariant. This mapping works as a solution generating technique, extending any given solution of a specific model to a (different) solution for any of the dual models along the whole duality orbit. We illustrate this technique by considering the duality orbits seeded by specific EMS models wherein solitonic and black hole solutions are known. For dilatonic models, specific rotations are equivalent to $S$-duality.Comment: 18 pages, 1 figur

Impact of delays on costumers'safety perceptions and behavioral intentions

Purpose: The main objective of this paper is to examine how the customers' perceptions of delays and safety relate to each other and to behavioral intentions Design/methodology/approach: We modified a customer satisfaction questionnaire to include questions relating to the constructs we wanted to examine and collaborated with a major international airline to collect data from 797 customers through in-flight surveys. Findings: We obtain three key original findings. First, perceived safety exerts a direct positive effect on behavioral intentions. Second, perceived delays exert an indirect effect mediated by perceived safety. Finally, customers believe operational practices affect both delay and safety. Originality/value: This is the first paper that examines the customer's perspective on two of the most important aspects of airline operations management: delays and safety. Our findings are of great value to managers who want to evaluate the impact of delays and safety on customers and to researches interested in the theoretical relationships between these two constructs.Peer Reviewe

Human Mobility in Large Cities as a Proxy for Crime

We investigate at the subscale of the neighborhoods of a highly populated city the incidence of property crimes in terms of both the resident and the floating population. Our results show that a relevant allometric relation could only be observed between property crimes and floating population. More precisely, the evidence of a superlinear behavior indicates that a disproportional number of property crimes occurs in regions where an increased flow of people takes place in the city. For comparison, we also found that the number of crimes of peace disturbance only correlates well, and in a superlinear fashion too, with the resident population. Our study raises the interesting possibility that the superlinearity observed in previous studies [Bettencourt et al., Proc. Natl. Acad. Sci. USA 104, 7301 (2007) and Melo et al., Sci. Rep. 4, 6239 (2014)] for homicides versus population at the city scale could have its origin in the fact that the floating population, and not the resident one, should be taken as the relevant variable determining the intrinsic microdynamical behavior of the system.Comment: 17 pages, 8 Figure

Habitat amount and ambient temperature dictate patterns of anuran diversity along a subtropical elevational gradient

Aim: Patterns of diversity along elevational gradients are driven by species characteristics but remain poorly understood. Filling this gap is imperative given the deteriorating conservation status of anurans worldwide. Here, we examine frog diversity and species composition along a sharp subtropical elevational gradient and assess the degree to which these are determined by environmental and spatial predictors. Location: An extensive southern Brazilian Atlantic Forest elevational gradient ranging from 300 to 1,800 m above sea level. Methods: We sampled 38 ponds and used structural equation modelling to examine the direct and indirect effects of area, climate, habitat amount, habitat complexity and productivity on frog species richness and abundance. We also applied joint species distribution models to investigate the importance of these predictors on frog species composition using species distribution and co-occurrence along the elevational gradient. Results: We recorded 12,636 individuals of 41 frog species. Frog species richness was highest at intermediate elevations, showing a hump-shaped pattern. Frog abundance was highest at lowlands and decreased towards higher elevations. We found support for only the habitat amount hypothesis in explaining overall species richness. Although temperature had a positive influence on productivity and frog abundance, neither predictors were related to species richness. Species composition diverged markedly between lowland and highland frog assemblages, which was mainly attributed to differences in ambient temperature. Main conclusion: Elevations containing more extensive natural habitat areas retained the most species-rich frog assemblages. The mid-elevational peak is likely attributed to lowland habitat (1,400 masl). The entire elevational gradient is, however, critical in maintaining anuran species diversity as lowland assemblages are distinct from those at mid- to high elevations. Our study also shows that anthropogenic habitat loss has a decisive effect on montane frog diversity, reinforcing the need to effectively protect these areas

Silk bilayer scaffolds can induce fast integration with subchondral bone and support cartilage repair

Publicado em : J Tissue Eng Regen Med 2014; 8 (Suppl. 1)Introduction: Osteochondral defect (OCD) regeneration presents major challenges in orthopedics. Since healing of cartilage and bone should be simultaneously considered, ideal scaffolds should be those that can mimic both tissues properties. In this study, bilayered silk and silk-nano calcium phosphate (Silk/Silk-NanoCaP) scaffolds with tailored mechanical properties were developed for OCD tissue engineering application. Materials and methods: Aqueous silk solution (16%) was prepared.1 Nano calcium phosphate particles (16%) were synthesized in the silk solution (Silk-NanoCaP).2 The bony layer was prepared by addition of NaCl particles (500–1000 lm) into the Silk-NanoCaP suspension. After drying for 2 days and salt-leaching overnight, silk solution was added on top of the bony layer using the same procedure to produce the chondral layer. The !nal scaffolds were evaluated through in vitro culture of rabbit bone marrow stromal cells (RBMSCs) for 2 weeks, and in vivo implantation in a rabbit knee OCD for 4 weeks. Results: The RBMSCs cultured in the scaffolds presented increasing viability from day 1 to day 7 by MTS assay. Good adhesion and migration of the RBMSCs in the scaffolds were achieved, as observed under the scanning electron microscope. Cell proliferation was observed from day 7 to day 14 as determined by DNA quanti!cation. The bony layer induced higher alkaline phosphatase level as compared to the chondral layer, in osteogenic condition. Histological analysis (H&E) showed that the bilayered scaffolds integrated well with the host tissue, after 4 weeks of implantation in a critical size OC defect (Fig. 1). Abundant new bone formation was detected in the Silk-NanoCaP layer. Cartilage regeneration occurred in the silk layer. Discussion and conclusions: The bilayered scaffolds favored the attachment, proliferation, and differentiation of RBMSCs. The bony layer of the bilayered scaffolds possessed osteoconductive properties. The bilayered scaffolds were biocompatible in vitro and in vivo. These scaffolds also induced both subchondral bone regeneration and supported cartilage regeneration, thus showing great promise in OCD regeneration. Acknowledgments: The authors thank FCT projects Tissue2Tissue and OsteoCart, and the FP7 Programme POLARIS. Yan LP was awarded a FCT PhD scholarship. Investigador FCT program (IF/00423/2012) and (IF/00411/2013) are also greatly acknowledged. Disclosure: The authors declare that there is no con"ict of interest