Effective field description of the Anton-Schmidt cosmic fluid

The effective theory of the Anton-Schmidt cosmic fluid within the Debye approximation is investigated. In this picture, the universe is modeled out by means of a medium without cosmological constant. In particular, the Anton-Schmidt representation of matter describes the pressure of crystalline solids under deformations imposed by isotropic stresses. The approach scheme is related to the fact that the universe deforms under the action of the cosmic expansion itself. Thus, we frame the dark energy term as a function of scalar fields and obtain the corresponding dark energy potential $V(\varphi)$. Different epochs of the universe evolution are investigated in terms of the evolution of $\varphi$. We show how the Anton-Schmidt equation of state is capable of describing both late and early epochs of cosmic evolution. Finally, numerical bounds on the Anton-Schmidt model with $n=-1$ are derived through a Markov Chain Monte Carlo analysis on the combination of data coming from type Ia Supernovae, observations of Hubble parameter and baryon acoustic oscillations. Statistical comparison with the $\Lambda$CDM model is performed by the AIC and BIC selection criteria. Results are in excellent agreement with the low-redshift data. A further generalization of the model is presented to satisfy the theoretical predictions at early-stage cosmology.Comment: 13 pages, Accepted for publication in Phys. Rev.

Pre-operative sera levels of CEA and CA19-9 and tissular distribution of tumor marker CA19-9 in colorectal carcinoma: correlation with morphological features of neoplasia

OBJETIVO: Comparar os níveis séricos de CA19-9 e CEA e a expressão tecidual do CA19-9 e relacioná-los com os aspectos morfológicos do carcinoma colorretal. MÉTODOS: Quarenta e cinco pacientes com carcinoma colorretal foram operados com coleta de CEA e CA19-9 séricos pré-operatórios. Valores séricos de CEA = 5,0ng/mL e de CA19-9 = 37UI/mL foram considerados aumentados. A avaliação da imunoexpressão do CA19-9 no tecido neoplásico foi realizada por meio de estudo imunoistoquímico com anticorpo monoclonal anti-CA19-9. A intensidade de expressão do CA19-9 no tecido neoplásico foi semiquantificada em leve(+/+++), moderada(++/+++), intensa(+++/+++) e ausente. RESULTADOS: Os valores do CA19-9 sérico foram progressivamente maiores conforme o aumento da expressão do CA19-9 no tecido neoplásico, porém sem significância (p=0,06). O aumento do nível sérico do CA19-9 foi acompanhado de elevação significante (p<0,001) do nível sérico do CEA. O nível sérico do CA19-9, a imunoexpressão tecidual do CA19-9 e o nível sérico do CEA não apresentaram associação significante com características morfológicas do carcinoma colorretal. CONCLUSÃO: As expressões sérica e tissular do CA19-9 demonstraram relação diretamente proporcional entre si, enquanto que os aspectos morfológicos da neoplasia não tiveram influência no CEA e CA19-9 séricos ou na imunoexpressão do CA19-9 tissular.OBJECTIVE: To compare sera levels of CEA and CA19-9 and tissular expression of the CA19-9 and to correlate these with morphological features of the colorectal carcinoma. METHODS: Forty five patients with colorectal carcinoma underwent surgical treatment following measurement of pre-operative levels of CA19-9 and CEA. Sera levels of CEA = 5.0ng/ml and CA19-9 = 37UI were deemed high values. Evaluation of CA19-9 immunoexpression in neoplastic tissue was carried through by means of immunohistochemical study with monoclonal antibody anti-CA19-9. The intensity of expression of CA19-9 in neoplastic areas was semi-quantified in each area of tumor differentiation into mild(+/+++), moderate(++/+++), intense(+++/+++) or absent. RESULTS: Sera CA19-9 values were progressively higher in the presence of elevated CA19-9 immunoexpression in colorectal carcinoma tissue, although not significant (p=0.06). Increased sera CA19-9 levels were found to be associated with significantly elevated (p<0.001) sera CEA levels. Levels of sera CA19-9, tissular immunoexpression of CA19-9 and sera levels of CEA presented no significant association with morphological features of the colorectal carcinoma. CONCLUSION: Sera and tissular levels of the CA19-9 marker exhibited, each other, a directly proportional relationship. The morphological features of the neoplasia had no influence on sera CEA or CA19-9 levels or tissular immunoexpression of CA19-9

De Sitter-like configurations with asymptotic quintessence environment

We examine a spherically-symmetric class of spacetimes carrying vacuum energy, while considering the influence of an external dark energy environment represented by a non-dynamical quintessence field. Our investigation focuses on a specific set of solutions affected by this field, leading to distinct kinds of spacetime deformations, resulting in regular, singular, and wormhole solutions. We thoroughly discuss the underlying physics associated with each case and demonstrate that more complex deformations are prone to instability. Ultimately, we find that our results lead to an \emph{isotropic de Sitter-like solution} that behaves as a quintessence fluid. To achieve this, we investigate the nature of the corresponding fluid, showing that it cannot provide the sound speed equal to a constant equation of state near the center. Consequently, we reinterpret the fluid as a slow-roll quintessence by investigating its behavior in asymptotic regimes. Further, we explore the potential implications of violating the isotropy condition on the pressures and we finally compare our findings with the de Sitter and Hayward solutions, highlighting both the advantages and disadvantages of our scenarios.Comment: 14 pages, 4 figures, 1 tabl

Repulsive regions in Lemaître–Tolman–Bondi gravitational collapse

We show that in the inhomogeneous Lemaître–Tolman–Bondi space–time there are specific regions in which repulsive gravity exists. To find these regions, we use an invariant definition of repulsive gravity based upon the behavior of the curvature eigenvalues. In addition, we analyze the effects of repulsive gravity on the dynamics of the gravitational collapse. In particular, we investigate the collapse in the case of the parabolic solution for the effective scale factor of the Lemaître–Tolman–Bondi metric, corresponding to the marginally bound case. Exploring the corresponding cut-offs at which gravity becomes repulsive, we notice that black holes with dominant repulsive effects are not excluded a priori. Indeed, we demonstrate that the collapse leads, in general, to the formation of a central naked singularity; however, for particular values of the free parameters entering the model, black holes with dominant repulsive gravity can exist. We show that the expected physical process is not modified as the marginally bound condition is dropped out. Moreover, we show that this is true independently of the hypothesis that the energy–momentum tensor is built up in terms of pressureless matter. Further, we demonstrate that geodesic deviations can depend on the sign of the curvature eigenvalues. Finally, we give an astrophysical interpretation of black holes with dominant repulsive gravity. Indeed, we argue that compact objects with dominant repulsive gravity could be interpreted as progenitors of Gamma Ray Bursts

Constraining primordial black holes as fraction of dark matter through accretion disk luminosity

In this paper, we consider the hypothesis that fractions of dark matter could be constituted by primordial black holes (PBHs). To test this possibility, we work out the observational properties of a static black hole embedded in the dark matter envelope made of a PBH source. The corresponding modifications of geometry due to such a physical system are investigated, with particular focus on the accretion disk luminosity in spiral galaxies. The impact of the PBH presence is analyzed through modification of the disk luminosity and kinematic quantities. Thus, we discuss possible constraints on the PBH abundance in view of the most recent theoretical bounds. The results of our study indicate that suitable PBH masses are $M_\text{PBH}\in[10^6,10^{12}]M_\odot$ for PBH fractions $f_\text{PBH}\in[10^{-3},1]$. In particular, a comparison with the predictions of the exponential sphere density profile for dark matter suggests that the best-matching configuration is achieved for $f_\text{PBH}=1$ and $M_\text{PBH}=10^6 M_\odot$. Consequences with respect to the current knowledge on primordial black hole physics are discussed.Comment: 9 pages, 6 figure

Superficial cervical plexus blockade improves pain control after thyroidectomy: A randomized controlled trial

OJECTIVES: The aim was to evaluate the ability of bilateral superficial cervical plexus blockade to control pain and to reduce the side effects of general anesthesia in patients submitted to thyroidectomy. METHODS: In this randomized controlled trial, we prospectively studied 100 consecutive patients who underwent total thyroidectomy. The simple random patient sample was divided into two groups: 50 patients received general anesthesia alone (group 1 [G1]), and 50 patients received general anesthesia with bilateral superficial cervical plexus blockade (group 2 [G2]). Statistical analyses were performed, and a 5% significance level was adopted. RESULTS: The mean arterial blood pressure and heart rate were 12% lower in G2 patients than in G1 patients 60 minutes after surgery (101 mmHg for G1 vs. 92.3 mmHg for G2; po0.001). G2 patients reported less pain than G1 patients, and opioid consumption was lower in G2 patients than in G1 patients, not upon postanesthesia care unit arrival, but at 30 minutes (2% vs. 34%; po0.001, respectively), 45 minutes (0% vs. 16%; p=0.006, respectively), and 4 hours postoperatively (6% vs. 20%; p=0.037, respectively). The incidence of nausea and vomiting was lower in G2 patients than in G1 patients from 45 minutes (0% vs. 16%; p=0.006, respectively) to 8 hours postoperatively (0% vs. 14%; p=0.012, respectively). CONCLUSIONS: The present study demonstrated that the combination of bilateral superficial cervical plexus blockade with general anesthesia for thyroidectomy is feasible, safe, and effective for achieving pain control and improving patient outcomes

Semi-Supervised vs. Supervised Learning for Discriminating Atrial Flutter Mechanisms Using the 12-lead ECG

Atrial flutter (AFl) is a common heart rhythm disorder driven by different self-sustaining electrophysiological atrial mechanisms. In this work, we tried to automatically distinguish the macro-mechanism sustaining the arrhythmia in an individual patient using the non-invasive 12-lead electrocardiogram (ECG). We implemented a concurrent clustering and classification algorithm (CCC) to discriminate the clinical classes and look for potential similarities between patient features in each class, thus suggesting that these patients would require a similar treatment. The CCC performance was then compared to a standard supervised technique (K-nearest neighbor, KNN). 3-class classification (macro-reentry right atrium, macro-reentry left atrium, and others) achieved 48.3% and 72.0% CCC and KNN accuracy, respectively. 4-class classification (tri-cuspidal reentry, mitral reentry, fig-8 macro-reentry, and others) achieved 41.6% and 71.2% CCC and KNN accuracy, respectively. Our results show that a clustering approach does not improve the performance of AFl classification because the semi-supervised method leads to clusters that are strongly overlapping between the different ground truth classes. In contrast, the supervised learning approach shows potential for the classification, although constrained by the complexity and the multiple variables that influence the underlying mechanisms

O abraço cruel da dor: a endometriose e as suas representações

Endometriosis is a chronic disease of the female genital tract, the etiology of which is still unclear. The purpose of this paper is to analyze, from a biopsychosocial perspective, the structure of social representations of endometriosis of women with this disease and healthy women. To this end, an exploratory survey was conducted by administering an online questionnaire. The results made it possible to identify those particular type of social representations, the controversies, articulated differently and often contradictory in their peripheral elements. These results provide a useful basis for the construction of intervention strategies to avoid the “epistemological purgatory” in which many women are forced to live due to the discrepancy between the subjective experience of endometriosis and its expert knowledge.La endometriosis es una enfermedad crónica del aparato genital femenino cuya etiología aún no está clara. El objetivo de este trabajo es analizar, desde una perspectiva biopsicosocial, la estructura de las representaciones sociales de la endometriosis entre mujeres con esta enfermedad y mujeres sanas. Para ello, se realizó una encuesta exploratoria mediante un cuestionario online. Los resultados permitieron identificar ese tipo particular de representaciones sociales, las polémicas, articuladas de manera diferente y a menudo contradictoria en sus elementos periféricos. Estos resultados constituyen una base útil para la construcción de estrategias de intervención destinadas a evitar el “purgatorio epistemológico” en el que muchas mujeres se ven obligadas a vivir debido a la discrepancia entre la experiencia subjetiva de la endometriosis y el conocimiento experto de la misma.L’endométriose est une maladie chronique de l’appareil génital féminin dont l’étiologie n’est pas encore élucidée. L’objectif de ce travail est d’analyser, dans une perspective biopsychosociale, la structure des représentations sociales de l’endométriose chez les femmes atteintes de cette maladie et chez les femmes saines. Pour faire ça, une enquête exploratoire a été menée au moyen d’un questionnaire en ligne. Les résultats ont permis d’identifier un type particulier de représentations sociales, les représentations polémiques, articulées différemment et souvent contradictoires dans leurs éléments périphériques. Ces résultats fournissent une base utile pour construire des stratégies d’intervention afin d’éviter le «purgatoire épistémologique» dans lequel de nombreuses femmes sont contraintes de vivre en raison du décalage entre leur expérience subjective de l’endométriose et la connaissance qu’en ont les experts.A endometriose é uma doença crónica do aparelho genital feminino, cuja etiologia ainda não está esclarecida. O objetivo deste trabalho é analisar, numa perspectiva biopsicossocial, a estrutura das representações sociais da endometriose entre mulheres com esta doença e mulheres saudáveis. Para o efeito, foi realizado um inquérito exploratório através de um questionário online. Os resultados permitiram identificar um tipo particular de representações sociais, as polémicas, articuladas de forma diferente e muitas vezes contraditória nos seus elementos periféricos. Estes resultados constituem uma base útil para a construção de estratégias de intervenção para evitar o “purgatório epistemológico” em que muitas mulheres são obrigadas a viver devido à discrepância entre a sua experiência subjetiva da endometriose e o seu conhecimento especializado da mesma

Non-Invasive Identification of Atrial Fibrillation Driver Location Using the 12-lead ECG: Pulmonary Vein Rotors vs. other Locations

Atrial fibrillation (AF) is an irregular heart rhythm due to disorganized atrial electrical activity, often sustained by rotational drivers called rotors. In the present work, we sought to characterize and discriminate whether simulated single stable rotors are located in the pulmonary veins (PVs) or not, only by using non-invasive signals (i.e., the 12-lead ECG). Several features have been extracted from the signals, such as Hjort descriptors, recurrence quantification analysis (RQA), and principal component analysis. All the extracted features have shown significant discriminatory power, with particular emphasis to the RQA parameters. A decision tree classifier achieved 98.48% accuracy, 83.33% sensitivity, and 100% specificity on simulated data.Clinical Relevance-This study might guide ablation procedures, suggesting doctors to proceed directly in some patients with a pulmonary veins isolation, and avoiding the prior use of an invasive atrial mapping system