89 research outputs found
An exercise on developing an ontology-epistemology about schizophrenia and neuroanatomy
This paper describes preliminary ideas on formalizing some concepts of neuroanatomy into ontological and epistemological terms. We envisage the application of this ontology on the assimilation of facts about medical knowledge about neuroimages from schizophrenic patients
Dynamics of Artificial Satellites around Europa
A planetary satellite of interest at the present moment for the scientific community is Europa, one of the four largest moons of Jupiter. There are some missions planned to visit Europa in the next years, for example, Jupiter Europa Orbiter (JEO, NASA) and Jupiter Icy Moon Explorer (JUICE, ESA). in this paper, we search for orbits around Europa with long lifetimes. Here, we develop the disturbing potential in closed form up to the second order to analyze the effects caused on the orbital elements of an artificial satellite around Europa. the equations of motion are developed in closed form to avoid expansions in power series of the eccentricity and inclination. We found polar orbits with long lifetimes. This type of orbits reduces considerably the maintenance cost of the orbit. We show a formula to calculate the critical inclination of orbits around Europa taking into account the disturbing potential due to the nonspherical shape of the central body and the perturbation of the third body.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo UNIFESP, Inst Ciencia & Tecnol, BR-12331280 Sao Jose Dos Campos, SP, BrazilINPE, Div Space Mech & Control, BR-12227010 Sao Jose Dos Campos, SP, BrazilUniversidade Federal de São Paulo UNIFESP, Inst Ciencia & Tecnol, BR-12331280 Sao Jose Dos Campos, SP, BrazilFAPESP: 2011/05671-5FAPESP: 2011/09310-7FAPESP: 2011/08171-3CNPq: 304700/2009-6CNPq: 3003070/2011-0Web of Scienc
Analysis of the orbital evolution of space debris using a solar sail and natural forces
In this work, the orbital evolution of these objects that are located in the
geostationary orbit (GEO) is analyzed. Knowing this, the possibility of using a
solar sail is considered to help to clean the space environment. The main
natural environmental perturbations that act in the orbit of the debris are
considered in the dynamics. Such forces acting in the solar sail can force the
growth of the eccentricity of these objects in the GEO orbit. Several authors
have presented models of the solar radiation pressure considering the
single-averaged model. But, doing a literature research, we found that the
authors consider the Earth around the Sun in a circular and inclined orbit. Our
contribution to the SRP model is in developing a different approach from other
authors, where we consider the Sun in an elliptical and inclined orbit, which
is valid for other bodies in the solar system when the eccentricity cannot be
neglected. The expression of the SRP is developed up to the second order. We
found that the first-order term is much superior to the second-order term, so
the quadrupole term can be neglected. Another contribution is the approach to
identify the initial conditions of the perigee argument (g) and the longitude
of the ascending node (h), where some values of the (g, h) plane contribute to
amplify the eccentricity growth. In the numerical simulations we consider real
data from space debris removed from the site Stuff in Space. The solar sail
helps to clean up the space environment using a propulsion system that uses the
Sun itself, a clean and abundant energy source, unlike chemical propellants, to
contribute to the sustainability of space exploration
Efeitos de Forças Gravitacionais e Não-Gravitacionais sobre o Movimento Orbital de Satélites Artificiais
Uma teoria para estudar o movimento orbital de satélites artificiais sobre efeitos do arrasto atmosférico e da pressão de radiação solar direta - considerando a sombra da Terra e alguns termos do geopotencial - é desenvolvida analiticamente. A sombra da Terra é modelada utilizando a função sombra (psi), como introduzida por Ferraz Mello: psi igual zero quando o satélite está na região de sombra e igual a um quando é iluminado pelo Sol. As componentes do arrasto são dadas por Vilhena de Moraes baseado no modelo atmosférico TD-88. O método de Hori para sistemas não-canônicos é aplicado para resolver as equações de movimento. Um software para manipulação algébrica é fundamental para fazer os cálculos necessários. Efeitos seculares e periódicos que influenciam no movimento orbital de satélites artificiais são analisados. É dada ênfase aos termos de acoplamento que surgem na solução do sistema de equações diferenciais. Utilizando dados orbitais do satélite CBERS-1 é feito um estudo para analisar ordens de grandeza da variação do semi-eixo maior devidas às perturbações consideradas
Analysis of the secular problem for triple star systems
The long-term dynamics of the three-body problem is studied. the goal is to study the motion of a planet (m(1)) around a star (m(0)) that is perturbed by a third-body (m(2)) (a planet or a brown dwarf star). the gravitational potential is developed in closed form up to the fourth order. Taking into account the triple system, it is shown here the evolution of some orbital parameters of the planet (m(1)). A comparison considering models with different orders for the disturbing potential is presented. We show that the behavior of the orbit of the inner planet can flip from prograde to retrograde trajectories. This is due to the third-order term, which strongly affects the eccentricity and inclination. We show that the effect of the fourth order term is to change the times when the phenomenon occurs.Universidade Federal de São Paulo, UNIFESP ICT, Sao Jose Dos Campos, SP, BrazilUniversidade Federal de São Paulo, UNIFESP ICT, Sao Jose Dos Campos, SP, BrazilWeb of Scienc
New Records and Potential Distribution of the ant Gracilidris pombero Wild & Cuezzo (Hymenoptera: Formicidae)
Gracilidris pombero Wild & Cuezzo, 2006 is an ant that remains poorly studied. Endemic from South America, its geographical distribution is known from few and scattered collection points. In this study, we present new occurrence records of G. pombero obtained through extensive collections along the Cerrado biome and the Atlantic Forest of northeastern Brazil. Based on the new and existing occurrence records we produced a model of the geographic distribution of G. pombero. Modelling method was chosen based on maximization of model performance after evaluating a series of modelling approaches, including different parametrizations of the Maxent algorithm and distinct runs of the GARP algorithm. We found a total of 43 new records of G. pombero in Brazil, including the first records of this species in the states of Goiás, Mato Grosso do Sul, Piauí, Sergipe and Tocantins. Based on our model, the areas of highest suitability of occurrence of G. pombero are located in two main zones in South America: one ranging from midwestern Brazil to southeastern Bolivia and Paraguay; and the other spanning the South of Brazil and Uruguay
Lower lip squamous cell carcinoma in patients with photosensitive disorders : analysis of cases treated at the Brazilian National Cancer Institute (INCA) from 1999 to 2012
Lower lip squamous cell carcinoma (LLSCC) is a common malignancy of the head and neck, being mainly a consequence of a chronic exposure to ultraviolet (UV) light solar radiation. Here, we evaluated the clinicopathological profile of patients with photosensitive disorders (xeroderma pigmentosum, lupus erythematosus and albinism) that developed LLSCC. Data from patients who had a diagnosed LLSCC with a prior xeroderma pigmentosum, lupus erythematosus or albinism diagnosis that were treated at INCA from 1999 to 2012 were collected from patients? medical records (n=16). The control group was composed of 68 patients with LLSCC without a medical history of photosensitivity. The clinicopathological data of this study population were collected and the association between these variables was analyzed by Fisher?s exact test. Survival curves were constructed using the Kaplan?Meier method and compared by log-rank test. All statistical analyses were performed using SPSS statistics package. The mean age of patients in the photosensitive and non-photosensitive groups was 42 years and 67 years, respectively (p<0.0001). A previous history of malignant diseases was more common in the photosensitive group (p=0.001). In both groups, most tumors showed a pathological stage I/II disease. Overall and cancer-specific survival were not statistically different. However, disease-free interval showed a significant difference (p=0.01) between the photosensitive and non-photosensitive patients. Photosensitive patients presented LLSCC at earlier age but it usually was not the primary tumor in these patients. Furthermore, a more aggressive pathological behavior was not seen when compared with tumors from non-photosensitive patients. The disease-free interval was lower in photosensitive patients, as expected
Is it necessary to increase the dose of levothyroxine in patients with hypothyroidism who use omeprazole? É necessário aumentar a dose de levotiroxina em pacientes com hipotireoidismo que usam omeprazol?
ABSTRACT Objective: It is believed that gastric pH interferes in levothyroxine absorption. Omeprazole, which acts by blocking the secretion of gastric acid, might interfere in hypothyroidism control in patients using levothyroxine and this effect could be dose dependent. The present study aimed to investigate this possibility. Subjects and methods: Twenty-one patients with primary hypothyroidism who had been using a stabilized levothyroxine dosage for at least one year were selected and randomly assigned to take omeprazole at the dosage of 40 mg or 20 mg per day. The mean levels of thyroid-stimulating hormone (TSH) before and 3 months after omeprazole usage were compared in the entire sample and in each group. Results: Ten patients concluded the entire treatment protocol in the 20 mg group and nine patients in the 40 mg group. There was no significant difference in TSH levels before and 3 months after omeprazole treatment in the entire patient sample (median levels: 2.28 vs. 2.30 mU/L, respectively: p = 0.56). Analysis of each subgroup (20 and 40 mg) showed no significant variation in TSH levels before and 3 months after omeprazole treatment (median levels: 2.24 vs. 2.42 mU/L, p = 0.62, and 2.28 vs. 2.30 mU/L, p = 0.82, respectively). No significant difference in the absolute (p = 0.93) or relative (p = 0.87) delta were observed between the two subgroups. Conclusion: Omeprazole in the dosage of 20 or 40 mg/day does not interfere in a clinically relevant manner in the treatment of patients with hypothyroidism that was previously under control. Arq Bras Endocrinol Metab. 2014;58(7):731-6 Keywords Hypothyroidism; thyroxine; absorption; omeprazole; proton pump inhibitors RESUMO Objetivo: Acredita-se que o pH gástrico possa interferir na absorção de levotiroxina. O omeprazol, ao inibir a secreção de ácido gástrico, poderia interferir no controle do hipotireoidismo em pacientes em uso de levotiroxina de forma dose-dependente. O presente estudo tem como objetivo investigar essa hipótese. Sujeitos e métodos: Vinte e um pacientes em uso de dose estável de levotiroxina por no mínimo um ano foram incluídos e aleatoriamente selecionados para iniciar o uso de omeprazol na dose de 40 mg ou 20 mg por dia. Foram comparados os níveis médios de hormônio tireoestimulante (TSH) antes e 3 meses após o uso de omeprazol, na amostra total e em cada grupo. Resultados: Dez pacientes concluíram o protocolo de tratamento no grupo de 20 mg e nove, no grupo de 40 mg. Não houve diferença significativa nos níveis de TSH antes e 3 meses após terapia com omeprazol na amostra total de pacientes (média: 2,28 vs. 2,30 mU/L, respectivamente: p = 0,56). A análise de cada subgrupo (20 e 40 mg) não demonstrou variação significativa nos níveis de TSH antes e 3 meses após terapia com omeprazol (média: 2,24 vs. 2,42 mU/L, p = 0,62 e 2,28 vs. 2,30 um/L, p = 0,82, respectivamente). Não houve diferença significativa no delta absoluto (p = 0,93) ou relativo (p = 0,87) entre os dois subgrupos. Conclusão: Omeprazol na dose de 20 ou 40 mg/dia não interfere de forma clinicamente relevante no tratamento de pacientes com hipotireoidismo previamente bem controlados. Arq Bras Endocrinol Metab. 2014;58(7):731-6 Descritore
SELAMENTO SUPERFICIAL E FORMAÇÃO DE CROSTA EM SOLOS REPRESENTATIVOS DO ESTADO DA PARAÍBA
The formation of seal and surface crust in the soil has direct consequences for the development of the crops and environmental quality, altering the soil structure, reducing the availability of water to the plants and favoring the erosion. The objective of this study was to evaluate the changes caused by successive rainfall events on the soil surface. Four soils were evaluated: Ferralsol; Acrisol; Leptsol; Luvisol. The selection criterion was based on pedogenetic development. The experiment was conducted under simulated rainfall, in experimental plots with a useful area of 0,3481 m², uncovered soil and slope of 0.10 mm-1. The tests were performed with mean precipitation intensity of 85 mm h-1 for 75 min, applied in three consecutive events at 7 day intervals, to determine the effects of surface sealing during rainfall and crust formation after the soil drying period. The hydraulic flow variables, the soil losses (PSi), soil disaggregation rate in interrill (Di) and the interrill erodibility factor (Ki) were evaluated. The formation of sealing and surface crusts were observed with increase of the flow velocity and liquid discharge, and the decrease of water sheet height, as well as in the changes in PSi, Di and Ki, being in the first event of simulated rainfall the greater contribution to formation of superficial crusting. TX showed the most stable after the successive events of simulated rainfall, even though the surface roughness was modified, did not present significant changes in the soil losses, disaggregation rate and soil interill erodibility.
Keywords: Interill erosion, semiarid, sediment concentration, surface roughness, hydraulic flow variables.A formação de selo e crosta superficial no solo tem consequências diretas para o desenvolvimento das culturas e qualidade ambiental, alterando sua estrutura, diminuindo a disponibilidade de água para as plantas e potencializando os efeitos da erosão. Diante disto, o presente trabalho teve como objetivo avaliar as alterações causadas por sucessivos eventos de precipitação na superfície dos solos. Foram avaliadas quatro classes de solos: Latossolo Amarelo (LA); Argissolo Vermelho (PV); Neossolo Litólico (RL); Luvissolo Háplico (TX). O critério de seleção teve como base o grau de desenvolvimento pedogenético. O experimento foi conduzido sob chuva simulada, em parcelas experimentais com área útil de 0,3481 m², com solo descoberto e declividade de 0,10 mm-1. Os testes foram realizados com intensidade média da precipitação ajustada em 85 mm h-1 durante 75 minutos, aplicadas em três eventos consecutivos com intervalos de 7 dias, para determinar os efeitos da formação do selamento superficial durante a chuva e a formação de crosta após o período de secagem do solo. Foram avaliadas as variáveis hidráulicas do escoamento, a perda de solo (PSi), taxa de desagregação do solo em entressulcos (Di) e o fator de erodibilidade em entressulcos (Ki). A formação de selamento e de crostas superficiais foram observadas com aumento da velocidade de escoamento e da descarga liquida, e a diminuição da altura da lamina de água, assim como nas alterações em PSi, Di e Ki, sendo no primeiro evento de chuva simulada a maior contribuição para formação do encrostamento superficial. O TX se mostrou o mais estável após os eventos sucessivos de chuva simulada, mesmo tendo a rugosidade superficial modificada, não apresentou alterações significativas nas perdas de solo, taxa de desagregação e erodibilidade do solo em entresulco.
Palavras Chave: Erosão entressulco, semiárido, concentração de sedimentos, rugosidade superficial, variáveis hidráulicas do escoamento
SELAMENTO SUPERFICIAL E FORMAÇÃO DE CROSTA EM SOLOS REPRESENTATIVOS DO ESTADO DA PARAÍBA
The formation of seal and surface crust in the soil has direct consequences for the development of the crops and environmental quality, altering the soil structure, reducing the availability of water to the plants and favoring the erosion. The objective of this study was to evaluate the changes caused by successive rainfall events on the soil surface. Four soils were evaluated: Ferralsol; Acrisol; Leptsol; Luvisol. The selection criterion was based on pedogenetic development. The experiment was conducted under simulated rainfall, in experimental plots with a useful area of 0,3481 m², uncovered soil and slope of 0.10 mm-1. The tests were performed with mean precipitation intensity of 85 mm h-1 for 75 min, applied in three consecutive events at 7 day intervals, to determine the effects of surface sealing during rainfall and crust formation after the soil drying period. The hydraulic flow variables, the soil losses (PSi), soil disaggregation rate in interrill (Di) and the interrill erodibility factor (Ki) were evaluated. The formation of sealing and surface crusts were observed with increase of the flow velocity and liquid discharge, and the decrease of water sheet height, as well as in the changes in PSi, Di and Ki, being in the first event of simulated rainfall the greater contribution to formation of superficial crusting. TX showed the most stable after the successive events of simulated rainfall, even though the surface roughness was modified, did not present significant changes in the soil losses, disaggregation rate and soil interill erodibility.
Keywords: Interill erosion, semiarid, sediment concentration, surface roughness, hydraulic flow variables.A formação de selo e crosta superficial no solo tem consequências diretas para o desenvolvimento das culturas e qualidade ambiental, alterando sua estrutura, diminuindo a disponibilidade de água para as plantas e potencializando os efeitos da erosão. Diante disto, o presente trabalho teve como objetivo avaliar as alterações causadas por sucessivos eventos de precipitação na superfície dos solos. Foram avaliadas quatro classes de solos: Latossolo Amarelo (LA); Argissolo Vermelho (PV); Neossolo Litólico (RL); Luvissolo Háplico (TX). O critério de seleção teve como base o grau de desenvolvimento pedogenético. O experimento foi conduzido sob chuva simulada, em parcelas experimentais com área útil de 0,3481 m², com solo descoberto e declividade de 0,10 mm-1. Os testes foram realizados com intensidade média da precipitação ajustada em 85 mm h-1 durante 75 minutos, aplicadas em três eventos consecutivos com intervalos de 7 dias, para determinar os efeitos da formação do selamento superficial durante a chuva e a formação de crosta após o período de secagem do solo. Foram avaliadas as variáveis hidráulicas do escoamento, a perda de solo (PSi), taxa de desagregação do solo em entressulcos (Di) e o fator de erodibilidade em entressulcos (Ki). A formação de selamento e de crostas superficiais foram observadas com aumento da velocidade de escoamento e da descarga liquida, e a diminuição da altura da lamina de água, assim como nas alterações em PSi, Di e Ki, sendo no primeiro evento de chuva simulada a maior contribuição para formação do encrostamento superficial. O TX se mostrou o mais estável após os eventos sucessivos de chuva simulada, mesmo tendo a rugosidade superficial modificada, não apresentou alterações significativas nas perdas de solo, taxa de desagregação e erodibilidade do solo em entresulco.
Palavras Chave: Erosão entressulco, semiárido, concentração de sedimentos, rugosidade superficial, variáveis hidráulicas do escoamento
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