Atmospheric NLTE-models for the spectroscopic analysis of massive stars

This work aims at advancing current tools for the quantitative optical spectroscopy of O-stars, in order to derive carbon, nitrogen and oxygen abundances using an automatized method applicable also to large samples of spectra. These abundances allow us to check current predictions on massive star evolution, and to establish tighter constraints on the impact of rotational mixing and other processes. Already on the Main Sequence, massive stars might display chemical abundance variations on short time-scales, where the CNO cycle produces nitrogen at the expense of carbon and - later on - oxygen. These variations represent a key feature to evaluate the reliability of corresponding theoretical models and are one of the main topics investigated in the present thesis.Das Ziel vorliegender Dissertation ist es, geeignete Werkzeuge für die quantitative Spektroskopie von O-Sternen im optischen Spektralbereich bereitz-stellen, um deren Kohlenstoff-, Stickstoff- und Sauerstoffhäufigkeiten zu bestimmen, und zwar mittels automatisierter Methoden, die auch auf große Stichproben anwendbar sind. Solche Häufigkeiten erlauben uns dabei, Vorhersagen aktueller Sternent-wickungsmodelle massereicher Sterne zu überprüfen, und insbesondere den Einfluss von Rotations-mischung und verwandter Prozesse einzugrenzen. Bereits auf der Hauptreihe können massereiche Sterne chemische Häufigkeitsvariationen auf kurzen Zeitskalen aufweisen, wobei der CNO-Zyklus Stickstoff auf Kosten von Kohlenstoff und - später - Sauerstoff produziert. Diese Variationen stellen ein Schlüsselmerkmal dar, um die Zuverlässigkeit entsprechender theoretischer Modelle zu bewerten, und sind eines der Hauptthemen vorliegender Arbeit

Carbon line formation and spectroscopy in O-type stars

The determination of chemical abundances constitutes a fundamental requirement for obtaining a complete picture of a star. Particularly in massive stars, CNO abundances are of prime interest, due to the nuclear CNO-cycle and various mixing processes which bring these elements to the surface. We aim at enabling a reliable carbon spectroscopy for our unified NLTE atmosphere code FASTWIND. We develop a new carbon model atom including CII/III/IV/V, and discuss problems related to carbon spectroscopy in O-type stars. We describe different tests to examine the reliability of our implementation, and investigate which mechanisms influence the carbon ionization balance. By comparing with high-resolution spectra from six O-type stars, we check in how far observational constraints can be reproduced by our new carbon line synthesis. Carbon lines are even more sensitive to a variation of temperature, gravity, and mass-loss rate, than hydrogen/helium lines. We are able to reproduce most of the observed lines from our stellar sample, and to estimate those specific carbon abundances which bring the lines from different ions into agreement. For hot dwarfs and supergiants earlier than O7, X-rays from wind-embedded shocks can impact the synthesized line strengths, particularly for CIV, potentially affecting the abundance determination. We have demonstrated our capability to derive realistic carbon abundances by means of FASTWIND, using our recently developed model atom. We found that complex effects can have a strong influence on the carbon ionization balance in hot stars. For a further understanding, the UV range needs to be explored as well. By means of detailed nitrogen and oxygen model atoms available to use, we will be able to perform a complete CNO abundance analysis for larger samples of massive stars, and to provide constraints on corresponding evolutionary models and aspects.Comment: 22 pages, 16 figures, 6 table

Atmospheric NLTE-Models for the Spectroscopic Analysis of Blue Stars with Winds. III. X-ray emission from wind-embedded shocks

X-rays/EUV radiation emitted from wind-embedded shocks in hot, massive stars can affect the ionization balance in their outer atmospheres, and can be the mechanism responsible for the production of highly ionized species. To allow for these processes in the context of spectral analysis, we have implemented such emission into our unified, NLTE model atmosphere/spectrum synthesis code FASTWIND. The shock structure and corresponding emission is calculated as a function of user-supplied parameters. We account for a temperature and density stratification inside the post-shock cooling zones, calculated for radiative and adiabatic cooling in the inner and outer wind, respectively. The high-energy absorption of the cool wind is considered by adding important K-shell opacities, and corresponding Auger ionization rates have been included into the NLTE network. We tested and verified our implementation carefully against corresponding results from various alternative model atmosphere codes, and studied the effects from shock emission for important ions from He, C, N, O, Si, and P. Surprisingly, dielectronic recombination turned out to play an essential role for the ionization balance of OIV/OV around Teff = 45,000 K. Finally, we investigated the behavior of the mass absorption coefficient, kappa_nu(r), important in the context of X-ray line formation in massive star winds. In almost all considered cases, direct ionization is of major influence, and Auger ionization significantly affects only NVI and OVI. The approximation of a radially constant kappa_nu is justified for r > 1.2 Rstar and lambda < 18 A, and also for many models at longer wavelengths. To estimate the actual value of this quantity, however, the HeII opacities need to be calculated from detailed NLTE modeling, at least for wavelengths longer than 18 to 20 A, and information on the individual CNO abundances has to be present.Comment: accepted by A&

Atmospheric NLTE-models for the spectroscopic analysis of massive stars

This work aims at advancing current tools for the quantitative optical spectroscopy of O-stars, in order to derive carbon, nitrogen and oxygen abundances using an automatized method applicable also to large samples of spectra. These abundances allow us to check current predictions on massive star evolution, and to establish tighter constraints on the impact of rotational mixing and other processes. Already on the Main Sequence, massive stars might display chemical abundance variations on short time-scales, where the CNO cycle produces nitrogen at the expense of carbon and - later on - oxygen. These variations represent a key feature to evaluate the reliability of corresponding theoretical models and are one of the main topics investigated in the present thesis.Das Ziel vorliegender Dissertation ist es, geeignete Werkzeuge für die quantitative Spektroskopie von O-Sternen im optischen Spektralbereich bereitz-stellen, um deren Kohlenstoff-, Stickstoff- und Sauerstoffhäufigkeiten zu bestimmen, und zwar mittels automatisierter Methoden, die auch auf große Stichproben anwendbar sind. Solche Häufigkeiten erlauben uns dabei, Vorhersagen aktueller Sternent-wickungsmodelle massereicher Sterne zu überprüfen, und insbesondere den Einfluss von Rotations-mischung und verwandter Prozesse einzugrenzen. Bereits auf der Hauptreihe können massereiche Sterne chemische Häufigkeitsvariationen auf kurzen Zeitskalen aufweisen, wobei der CNO-Zyklus Stickstoff auf Kosten von Kohlenstoff und - später - Sauerstoff produziert. Diese Variationen stellen ein Schlüsselmerkmal dar, um die Zuverlässigkeit entsprechender theoretischer Modelle zu bewerten, und sind eines der Hauptthemen vorliegender Arbeit

Systemic relations among the variables involved in occupational accidents of the nursing team in a psychiatric hospital

Background: The occupational activities carried out in hospital environments pose occupational risks to professionals. In psychiatric hospitals, due to the characteristics of the patients treated, professionals are also subjected to other risks, such as physical aggression. Objective: This research aimed to identify the systemic context, highlighting the cause-and-effect relationships that culminate in occupational accidents that occurred with the nursing staff in a psychiatric hospital in Brazil. Methods: The current study is an applied research and was divided into three stages. First, the collection of data related to the case study was made and accidents were analyzed and occupational hazards were identified. In the second stage, from the collected information, occupational safety indicators were defined. Lastly, in the third stage, the qualitative aspect of System Dynamics was applied to perform the systemic analysis and to identify how the different variables were related. Results: The results showed that physical aggression was the main cause of accidents. Regarding safety indicators, while both the level of use of Personal Protective Equipment (PPE) by professionals and the high level of PPE protection were positive aspects, the level of training of professionals to use PPE was a negative aspect. The Causal Link Diagram (CLD) showed that the perception of risk influenced the level of use of PPE and those organizational measures influenced the accident rate. Conclusion: In conclusion, the systemic analysis of the system dynamics can optimize the diagnostic process of occupational accidents in psychiatric hospitals, and especially help to identify the cause and effect among the variables involved.- (undefined

Efeito da data de semeadura para duas cultivares contrastantes de feijão.

Nesse estudo, utilizou-se duas cultivares, a Radiante que apresenta ciclo curto e a Pérola, de ciclo médio, com o objetivo de avaliar a produtividade e seus componentes em quatro diferentes datas de plantio (15/06/2011; 29/06/2011; 13/07/2011 e 28/07/2011)

Inspiratory fraction and exercise impairment in COPD patients GOLD stages II-III

The inspiratory-to-total lung capacity ratio or inspiratory fraction (inspiratory capacity (IC)/total lung capacity (TLC)) may be functionally more representative than traditional indices of resting airflow limitation and lung hyperinflation in patients with chronic obstructive pulmonary disease (COPD).In the present retrospective study, a comparison was made of the individual performance of post-bronchodilator IC, IC/TLC and forced expiratory volume in one second (FEV1) in predicting a severely reduced peak oxygen uptake (V'o(2); < 60% predicted) in 44 COPD patients Global Initiative for Chronic Obstructive Lung Disease stages II-III (post-bronchodilator FEV1 ranging from 31-79% pred).Patients with lower IC/TLC values (<= 0.28) showed increased lung volumes and reduced exercise capacity as compared with other subjects. Following a multiple linear regression analysis, only IC/TLC and FEV1 remained as independent predictors of V'o(2) (r(2)=0.33). A receiver operating characteristic (ROC) curve analysis revealed that an IC/TLC <= 0.28 had the highest specificity (89.6%), positive predictive value (80%) and overall accuracy (86.3%) in identifying patients with V'o(2)< 60% pred. in addition, the area under the ROC curve tended to be higher for IC/TLC than IC.In conclusion, post-bronchodilator total lung capacity-corrected inspiratory fraction provides useful information in addition to forced expiratory volume in one second and inspiratory capacity, to estimate the likelihood of chronic obstructive pulmonary disease patients to present with severely reduced maximal exercise capacity.Universidade Federal de São Paulo, Paulista Sch Med, Pulm Funct & Clin Exercise Physiol Unit, Resp Div,Dept Med,EPM, BR-04020050 São Paulo, BrazilUniversidade Federal de São Paulo, Paulista Sch Med, Pulm Funct & Clin Exercise Physiol Unit, Resp Div,Dept Med,EPM, BR-04020050 São Paulo, BrazilWeb of Scienc

Decision-making framework for implementing safer human-robot collaboration workstations: system dynamics modeling

Human-Robot Collaboration (HRC) systems are often implemented seeking for reducing risk of Work-related Musculoskeletal Disorders (WMSD) development and increasing productivity. The challenge is to successfully implement an industrial HRC to manage those factors, considering that non-linear behaviors of complex systems can produce counterintuitive effects. Therefore, the aim of this study was to design a decision-making framework considering the key ergonomic methods and using a computational model for simulations. It considered the main systemic influences when implementing a collaborative robot (cobot) into a production system and simulated scenarios of productivity and WMSD risk. In order to verify whether the computational model for simulating scenarios would be useful in the framework, a case study in a manual assembly workstation was conducted. The results show that both cycle time and WMSD risk depend on the Level of Collaboration (LoC). The proposed framework helps deciding which cobot to implement in a context of industrial assembly process. System dynamics were used to understand the actual behavior of all factors and to predict scenarios. Finally, the framework presented a clear roadmap for the future development of an industrial HRC system, drastically reducing risk management in decision-making.This work was supported by European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Programme (COMPETE 2020) [Project n◦ 39479; Funding Reference: POCI-01-0247-FEDER-39479] and by FCT - Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/202

Augmented β-cell function and mass in glucocorticoid-treated rodents are associated with increased islet ir-β /AKT/mTOR and decreased AMPK/ACC and AS160 signaling

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOGlucocorticoid (GC) therapies may adversely cause insulin resistance (IR) that lead to a compensatory hyperinsulinemia due to insulin hypersecretion. The increased β-cell function is associated with increased insulin signaling that has the protein kinase B (AKT) substrate with 160 kDa (AS160) as an important downstream AKT effector. In muscle, both insulin and AMP-activated protein kinase (AMPK) signaling phosphorylate and inactivate AS160, which favors the glucose transporter (GLUT)-4 translocation to plasma membrane. Whether AS160 phosphorylation is modulated in islets from GC-treated subjects is unknown. For this, two animal models, Swiss mice and Wistar rats, were treated with dexamethasone (DEX) (1 mg/kg body weight) for 5 consecutive days. DEX treatment induced IR, hyperinsulinemia, and dyslipidemia in both species, but glucose intolerance and hyperglycemia only in rats. DEX treatment caused increased insulin secretion in response to glucose and augmented β-cell mass in both species that were associated with increased islet content and increased phosphorylation of the AS160 protein. Protein AKT phosphorylation, but not AMPK phosphorylation, was found significantly enhanced in islets from DEX-treated animals. We conclude that the augmented β-cell function developed in response to the GC-induced IR involves inhibition of the islet AS160 protein activity.Glucocorticoid (GC) therapies may adversely cause insulin resistance (IR) that lead to a compensatory hyperinsulinemia due to insulin hypersecretion. The increased β-cell function is associated with increased insulin signaling that has the protein kinase2014114FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOsem informaçãosem informaçã

S-Nitroso-N-Acetylcysteine Ameliorates Ischemia-Reperfusion Injury In The Steatotic Liver

BACKGROUND: Steatosis is currently the most common chronic liver disease and it can aggravate ischemia-reperfusion (IR) lesions. We hypothesized that S-nitroso-N-acetylcysteine (SNAC), an NO donor component, can ameliorate cell damage from IR injury. In this paper, we report the effect of SNAC on liver IR in rats with normal livers compared to those with steatotic livers. METHODS: Thirty-four rats were divided into five groups: I (n=8), IR in normal liver; II (n=8), IR in normal liver with SNAC; III (n=9), IR in steatotic liver; IV (n=9), IR in steatotic liver with SNAC; and V (n=10), SHAN. Liver steatosis was achieved by administration of a protein-free diet. A SNAC solution was infused intraperitoneally for one hour, beginning 30 min. after partial (70%) liver ischemia. The volume of solution infused was 1 ml/100 g body weight. The animals were sacrificed four hours after reperfusion, and the liver and lung were removed for analysis. We assessed hepatic histology, mitochondrial respiration, oxidative stress (MDA), and pulmonary myeloperoxidase. RESULTS: All groups showed significant alterations compared with the group that received SHAN. The results from the steatotic SNAC group revealed a significant improvement in liver mitochondrial respiration and oxidative stress compared to the steatotic group without SNAC. No difference in myeloperoxidase was observed. Histological analysis revealed no difference between the non-steatotic groups. However, the SNAC groups showed less intraparenchymal hemorrhage than groups without SNAC (p=0.02). CONCLUSION: This study suggests that SNAC effectively protects against IR injury in the steatotic liver but not in the normal liver