2,981 research outputs found
Stellar equilibrium configurations of white dwarfs in the gravity
In this work we investigate the equilibrium configurations of white dwarfs in
a modified gravity theory, na\-mely, gravity, for which and
stand for the Ricci scalar and trace of the energy-momentum tensor,
respectively. Considering the functional form , with
being a constant, we obtain the hydrostatic equilibrium equation for
the theory. Some physical properties of white dwarfs, such as: mass, radius,
pressure and energy density, as well as their dependence on the parameter
are derived. More massive and larger white dwarfs are found for
negative values of when it decreases. The equilibrium configurations
predict a maximum mass limit for white dwarfs slightly above the Chandrasekhar
limit, with larger radii and lower central densities when compared to standard
gravity outcomes. The most important effect of theory for massive
white dwarfs is the increase of the radius in comparison with GR and also
results. By comparing our results with some observational data of
massive white dwarfs we also find a lower limit for , namely, .Comment: To be published in EPJ
Recent changes in trends of mortality from cervical cancer in Southeastern Brazil
OBJECTIVE: To analyze the trends of cervical cancer mortality in Brazilian Southeastern states, and to compare them to Brazil and other regions between 1980 and 2020. METHODS: Time series study based on data from the Sistema de Informações de Mortalidade (Brazilian Mortality Information System). Death data were corrected by proportional redistribution of deaths from ill-defined causes and cervical cancer of unspecified portion. Age-standardized and age-specific rates were calculated by screening target (25–39 years; 40–64 years) and non-target (65 years or older) age groups. Annual percentage changes (APC) were estimated by linear regression model with breakpoints. The coverage of Pap Smear exam in the Unified Health System (SUS) was evaluated between 2009 and 2020 according to age group and locality. RESULTS: There were increases in corrected mortality rates both in 1980 and in 2020 in all regions, with most evident increments at the beginning of the series. There was a decrease in mortality nationwide between 1980-2020; however, the state of São Paulo showed a discrete upward trend in 2014-2020 (APC=1.237; 95%CI 0.046-2.443). Noteworthy is the trend increment in the 25–39 year-old group in all study localities, being sharper in the Southeast region in 2013-2020 (APC=5.072; 95%CI 3.971-6.185). Screening coverage rates were highest in São Paulo and lowest in Rio de Janeiro, with a consistent decline from 2012 onwards at all ages. CONCLUSIONS: São Paulo is the first Brazilian state to show a reversal trend in mortality from cervical cancer. The changes in mortality patterns identified in this study point to the need for reorganization of the current screening program, which should be improved to ensure high coverage, quality, and adequate follow-up of all women with altered test results.OBJETIVO: Analisar as tendências da mortalidade por câncer de colo de útero nos estados da região Sudeste e compará-las com o Brasil e demais regiões entre 1980 e 2020. MÉTODOS: Estudo de série temporal com base nos dados do Sistema de Informações de Mortalidade. Os dados de óbito foram corrigidos por redistribuição proporcional das mortes por causas mal definidas e por câncer de útero de porção não especificada. Foram calculadas taxas padronizadas por idade e específicas por faixas etárias alvo de rastreamento (25–39 anos; 40–64 anos) e não alvo (65 anos ou mais). Variações percentuais anuais foram estimadas por modelo de regressão linear com pontos de quebra. A cobertura do exame Papanicolau no Sistema Único de Saúde (SUS) foi avaliada entre 2009 e 2020 segundo faixa etária e localidade. RESULTADOS: Foram verificados aumentos das taxas de mortalidade corrigidas tanto em 1980 como em 2020 em todas as regiões, com incrementos mais evidentes no início da série. Houve queda da mortalidade em todo o país entre 1980-2020, entretanto, o estado de São Paulo apresentou discreta tendência de aumento em 2014-2020 (APC=1,237; IC95% 0,046–2,443). Destaca-se o incremento da tendência no grupo de 25–39 anos em todas as localidades de estudo, mostrando-se mais acentuado na região Sudeste em 2013–2020 (APC=5,072; IC95% 3,971–6,185). As taxas de cobertura de rastreamento foram mais elevadas em São Paulo e mais baixas no Rio de Janeiro, com queda consistente a partir de 2012 em todas as idades. CONCLUSÕES: São Paulo é o primeiro estado brasileiro a apresentar inversão de tendência da mortalidade por câncer de colo do útero. As mudanças nos padrões de mortalidade identificadas neste estudo apontam para a necessidade de reorganização do atual programa de rastreamento, que deve ser aperfeiçoado para garantir alta cobertura, qualidade e seguimento adequado de todas as mulheres com exames alterados
Simultaneous Papillary Carcinoma in Thyroglossal Duct Cyst and Thyroid
Thyroglossal duct cyst (TDC) is a cystic expansion of a remnant of the thyroglossal duct tract. Carcinomas in the TDC are extremely rare and are usually an incidental finding after the Sistrunk procedure. In this report, an unusual case of a 36-year-old woman with concurrent papillary thyroid carcinoma arising in the TDC and on the thyroid gland is presented, followed by a discussion of the controversies surrounding the possible origins of a papillary carcinoma in the TDC, as well as the current management options
Gravity-driven instability in a spherical Hele-Shaw cell
A pair of concentric spheres separated by a small gap form a spherical
Hele-Shaw cell. In this cell an interfacial instability arises when two
immiscible fluids flow. We derive the equation of motion for the interface
perturbation amplitudes, including both pressure and gravity drivings, using a
mode coupling approach. Linear stability analysis shows that mode growth rates
depend upon interface perimeter and gravitational force. Mode coupling analysis
reveals the formation of fingering structures presenting a tendency toward
finger tip-sharpening.Comment: 13 pages, 4 ps figures, RevTex, to appear in Physical Review
External marking and behavior of early instar \u3ci\u3eHelicoverpa armigera\u3c/i\u3e (Lepidoptera: Noctuidae) on soybean
Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a pest of major agricultural crops, such as soybean and cotton. A better understanding of larval movement is important for its integrated management and resistance management. Studies with neonates through second instar larvae are still limited by the difficulties involving the handling and observation of these instars. Many studies require marking larvae, and most research involving marking is focused on moths. However, our study investigated aspects of larval behavior of the second instar of H. armigera on soybean plants. The dyes luminous powder red and Sudan Red 7B were tested as external larval markers. Both dyes successfully marked the larvae for most of 1 stadium (48 h) without deleterious effects, and are useful for short-period behavioral studies. Luminous powder red was selected for the H. armigera larval behavior study on soybean because of ease of detection during both day and night. Second instar on-plant movement was consistent, independent of the d period (morning, afternoon, evening). In general, larvae established their feeding site within a few hours of release, and remained feeding on soybean leaves. Second instar behavior suggests that management by nocturnal insecticide application, based on H. armigera larval movement, would not have an advantage over daytime application.
Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) está entre as principais pragas de importancia para culturas agrícolas, como soja e algodão. Compreender o comportamento larval desta espécie, principalmente durante os estádios iniciais é de suma importância para seu manejo integrado e para o manejo de populações resistentes. No entanto, pesquisas com neonatas ou lagartas de segundo ínstar são limitadas devido às dificuldades envolvendo o manuseio e observação de insetos tão diminutos. Muitos desses estudos requerem a marcação de indivíduos, e até o momento, a maioria das pesquisas com marcação de insetos é focada em adultos. Assim, nosso estudo investigou aspectos do comportamento de lagartas de segundo instar de H. armigera em plantas de soja. Estudos prévios também foram realizados com o intuito de se avaliar métodos alternativos e eficazes para marcação de estádios iniciais das larvas desse noctuídeo e suas aplicações em estudos de comportamento. Para tanto, os corantes luminous powder (azul e vermelho) e Sudan (azul e vermelho 7B) foram testados por meio da incorporação em dieta artifical e polvilhamento sobre as lagartas. Baseado em nossos ensaios prévios de laboratório, os corantes incorporados na dieta artifical apresentaram efeitos variáveis sobre os parâmetros biológicos de H. armigera e baixa persistência após o segundo ínstar. Os corantes aplicados por polvilhamento marcaram com sucesso as lagartas e luminous powder vermelho foi selecionado para o estudo de comportamento de lagartas de segundo ínstar em plantas de soja. Lagartas de segundo ínstar apresentaram comportamento de movimento nas plantas semelhantes, independentemente do período de avaliação (manhã, tarde e noite). Em geral, a maioria das lagartas estabeleceram seu sítio de alimentação após algumas horas e permaneceram se alimentando sobre as folhas de soja. Os resultados de comportamento de larvas de H. armigera em segundo instar, documentado no presente trabalho, indicam que aplicacões noturnas de insecticidas não representa vantagem para aumento da eficiência de controle, quando comparado com aplicacões de inseticidas durante o dia
A combined theoretical and experimental study of electronic structure and optical properties of β-ZnMoO4 microcrystals
In this paper, a combined theoretical and experimental study on the electronic structure
and photoluminescence (PL) properties of beta zinc molybdate ( -ZnMoO4) microcrystals
synthesized by the hydrothermal method has been employed. These crystals were
structurally characterized by means of X-ray diffraction (XRD), Rietveld refinement,
Fourier transform Raman (FT-Raman) and Fourier transform infrared (FT-IR) spectroscopies.
Their optical properties were investigated by ultraviolet-visible (UV-vis) absorption
spectroscopy and PL measurements. First-principles quantum mechanical calculations
based on the density functional theory at the B3LYP calculation level have been
carried out. XRD patterns, Rietveld refinement, FT-Raman and FT-IR spectra showed
that these crystals have a wolframite-type monoclinic structure. The Raman and IR frequencies experimental results are in reasonable agreement with theoretically calculated results. UV-vis absorption measurements shows an optical band gap value of 3.17 eV, while the calculated band structure has a value of 3.22 eV. The density of states indicate that the main orbitals involved in the electronic structure of -ZnMoO4 crystals are (O2p-valence band and Mo 4d-conduction band). Finally, PL properties of -ZnMoO4 crystals are explained by distortions effects in octahedral [ZnO6] and [MoO6] clusters and inhomogeneous electronic distribution into the lattice with the electron density map
Effect of antibodies to intercellular adhesion molecule type 1 on the protection of distant organs during reperfusion syndrome in rats
We investigated kidney and lung alterations caused by intercellular adhesion molecule type 1 (ICAM-1) blockade after ischemia and reperfusion of hind limb skeletal muscles. Rats were submitted to ligature of the infrarenal aorta for 6 h. The animals were randomized into three groups of 6 rats each: group I, sacrificed after ischemia; group II, reperfusion for 24 h, and group III, reperfusion for 24 h after receiving monoclonal anti-ICAM-1 antibodies. At the end of the experiment, blood samples were collected for creatinine, lactate dehydrogenase, creatine phosphokinase, potassium, pH and leukocyte counts. Samples were taken from the muscles of the hind limbs and from the kidneys and lungs for histological analysis and measurement of the neutrophil infiltrate by myeloperoxidase staining. The groups did not differ significantly with regard to the laboratory tests. There were no major histological alterations in the kidneys. An intense neutrophil infiltrate in the lungs, similar in all groups, was detected. Myeloperoxidase determination showed that after reperfusion there was significantly less retention of polymorphonuclear neutrophils in the muscles (352 ± 70 vs 1451 ± 235 × 10² neutrophils/mg; P<0.01) and in the kidneys (526 ± 89 vs 852 ± 73 × 10² neutrophils/mg; P<0.01) of the animals that received anti-ICAM-1 before perfusion compared to the group that did not. The use of anti-ICAM-1 antibodies in this experimental model minimized neutrophil influx, thus reducing the inflammatory process, in the muscles and kidneys after ischemia and reperfusion of the hind limbs.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de CirurgiaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de ClínicaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de PatologiaUNIFESP, EPM, Depto. de CirurgiaUNIFESP, EPM, Depto. de ClínicaUNIFESP, EPM, Depto. de PatologiaSciEL
Reconstruction of TMJ with Prosthesis Joint
Temporomandibular joint (TMJ) and the associated muscles turn possible mandibular movements as a complex engineering appliance that may be affected by signs and symptoms such as pain, including in head and neck areas, abnormal jaw movement and clicking or crepitus sounds, classified as temporomandibular disorders (TMD). Some procedures such as discopexy, eminectomy, or arthroplasties, which we consider conservative, can result in ankylosis, even resorption and joint degeneration, limiting surgical options to treat TMJ. The alloplastic prosthesis becomes an option. Total joint reconstruction using prosthesis becomes the treatment choice during the following conditions: previous surgeries including autogenous grafts fail; presence of arthritic diseases; fibrous or bony ankylosis; tumors involving the TMJ; loss of vertical posterior mandible dimension by other TMJ pathologies; and previous prosthetic joint fail. The use of TMJ prosthesis, when compared to other reconstructive procedures, provides immediate function, reducing the duration of surgery and hospitalization time. Disadvantages of the TMJ prosthesis include high cost, prosthesis failure, functional mandibular movements loss, such as protrusion and laterality, and limited fit of stock prosthesis
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