Terrestrial Planet Formation Constrained by Mars and the Structure of the Asteroid Belt

Reproducing the large Earth/Mars mass ratio requires a strong mass depletion in solids within the protoplanetary disk between 1 and 3 AU. The Grand Tack model invokes a specific migration history of the giant planets to remove most of the mass initially beyond 1 AU and to dynamically excite the asteroid belt. However, one could also invoke a steep density gradient created by inward drift and pile-up of small particles induced by gas-drag, as has been proposed to explain the formation of close-in super Earths. Here we show that the asteroid belt's orbital excitation provides a crucial constraint against this scenario for the Solar System. We performed a series of simulations of terrestrial planet formation and asteroid belt evolution starting from disks of planetesimals and planetary embryos with various radial density gradients and including Jupiter and Saturn on nearly circular and coplanar orbits. Disks with shallow density gradients reproduce the dynamical excitation of the asteroid belt by gravitational self-stirring but form Mars analogs significantly more massive than the real planet. In contrast, a disk with a surface density gradient proportional to $r^{-5.5}$ reproduces the Earth/Mars mass ratio but leaves the asteroid belt in a dynamical state that is far colder than the real belt. We conclude that no disk profile can simultaneously explain the structure of the terrestrial planets and asteroid belt. The asteroid belt must have been depleted and dynamically excited by a different mechanism such as, for instance, in the Grand Tack scenario.Comment: Accepted for publication in MNRA

Assessing the spin-orbit obliquity of low-mass planets in the breaking the chain formation model: A story of misalignment

The spin-orbit obliquity of a planetary system constraints its formation history. A large obliquity may either indicate a primordial misalignment between the star and its gaseous disk or reflect the effect of different mechanisms tilting planetary systems after formation. Observations and statistical analysis suggest that system of planets with sizes between 1 and 4 R$_{\oplus}$ have a wide range of obliquities ($\sim0-30^{\circ}$), and that single- and multi-planet transiting have statistically indistinguishable obliquity distributions. Here, we revisit the ``breaking the chains'' formation model with focus in understanding the origin of spin-orbit obliquities. This model suggests that super-Earths and mini-Neptunes migrate close to their host stars via planet-disk gravitational interactions, forming chain of planets locked in mean-motion resonances. After gas-disk dispersal, about 90-99\% of these planetary systems experience dynamical instabilities, which spread the systems out. Using synthetic transit observations, we show that if planets are born in disks where the disk angular momentum is virtually aligned with the star's rotation spin, their final obliquity distributions peak at about $\sim$5 degrees or less, and the obliquity distributions of single and multi-planet transiting systems are statistically distinct. By treating the star-disk alignment as a free-parameter, we show that the obliquity distributions of single and multi-planet transiting systems only become statistically indistinguishable if planets are assumed to form in primordially misaligned natal disks with a ``tilt'' distribution peaking at $\gtrsim$10-20 deg. We discuss the origin of these misalignments in the context of star formation and potential implications of this scenario for formation models.Comment: 11 pages, 9 figures, 2 tables. Accepted for publication in MNRA

DIFUSÃO DE CONHECIMENTO SOBRE MELIPONÍNEOS DISSEMINATION OF KNOWLEDGE ON MELIPONIUMS

O objetivo do trabalho é levar o conhecimento adquirido ao longo do tempo sobre as abelhas nativas para alunos, servidores, e visitantes do IFC Campus Santa Rosa do Sul, para que estes possam reconhecer as mesmas na natureza, e todos juntos preservarem a existência de espécies tão essenciais para o meio ambiente. Difundir conhecimento sobre as abelhas nativas é fundamental. Deve ser constante, pois novas informações estão surgindo frequentemente. E deve estar associado a sua função de polinização e seu potencial na geração de rentável

Bullying como violência sistemática que conduz à estigmatização nas escolas de futebol

Thousands of children walk the soccer path as a sports practice in Brazil. Bullying is a phenomenon present in the family, school and sports environment, including in soccer sports schools, and that generates many harmful consequences. The methodology used in this study was bibliographic research, based on digital journals. The main targets of bullying in the soccer schools are the students with motor difficulties, obesity or with some deficiency and also the girls. It is concluded that football, teacher, parents and other people that participate in the training process should be attentive to avoid the occurrence of the bullying phenomenon, seeking through education and sports to contribute to the development of values such as respect, confidence, self-cooperation, valuing the group work, the healthy practice and the friendship.Miles de niños recorren el camino de la práctica deportiva del fútbol en Brasil. El bullying es un fenómeno presente en el ambiente familiar, escolar y deportivo, incluso en escuelas deportivas de fútbol, y que genera muchas consecuencias nocivas. La metodología utilizada fue la pesquisa bibliográfica, con base en periódicos digitales. Los principales centros de bullying en las escuelas de fútbol son los alumnos con dificultades motoras, obesidad, o con alguna discapacidad y las niñas. Se concluye que el fútbol, el profesor, padres y otras personas participantes del proceso formativo deben estar atentos para evitar la ocurrencia del fenómeno bullying, buscando, a través de la educación y del deporte, contribuir con el desarrollo de valores, como respeto, confianza, autoestima, cooperación, valorizando el trabajo grupo, la práctica saludable y la amistad.Milhares de crianças trilham o caminho da prática esportiva do futebol no Brasil. O bullying é um fenômeno presente no ambiente familiar, escolar e esportivo, inclusive em escolas esportivas de futebol, e que gera muitas consequências nocivas. A metodologia utilizada foi pesquisa bibliográfica, com base em periódicos digitais. Os principais alvos de bullying nas escolinhas de futebol são os alunos com dificuldades motoras, obesidade, ou com alguma deficiência e as meninas. Conclui-se que o futebol, o professor, pais e outras pessoas participantes do processo formativo devem estar atentos para evitar a ocorrência do fenômeno bullying, buscando através da educação e do esporte contribuir com o desenvolvimento de valores, como respeito, confiança, autoestima, cooperação, valorizando o trabalho em grupo, a prática saudável e a amizade

Autonomia da parturiente no contexto da assistência ao trabalho de parto induzido: estudo transversal

Objective. This study aims to analyze the autonomy of women in the assistance to induced labor. Method. This is a cross-sectional study conducted in the period from October 2019 to June 2021 through the application of an electronic questionnaire, built on Google Forms, containing closed questions. Results. 383 women responded to the questionnaire designed by the authors. The age of the participants ranged from 17 to 50 years. Among the participants, 28.8% had induced labor, of which 12.5% underwent mechanical induction, 62.5% received oxytocin and 25% prostaglandin/misoprostol. Conclusions. The autonomy of the parturient woman in conducting her delivery is paramount for professionals to act with good practices in childbirth care.Objetivo. Este estudio pretende analizar la autonomía de la mujer en la asistencia al parto inducido. Método. Se trata de un estudio transversal realizado en el periodo comprendido entre octubre de 2019 y junio de 2021 mediante la aplicación de un cuestionario electrónico, construido en Google Forms, que contiene preguntas cerradas. Resultados. 383 mujeres respondieron al cuestionario diseñado por los autores. La edad de los participantes oscilaba entre los 17 y los 50 años. Entre las participantes, el 28,8% tuvo un parto inducido, de las cuales el 12,5% se sometió a una inducción mecánica, el 62,5% recibió oxitocina y el 25% prostaglandina/misoprostol. Conclusiones. La autonomía de la parturienta en la conducción de su parto es primordial para que los profesionales tengan buenas prácticas en la asistencia al parto.Objetivo. Este estudo tem por objetivo analisar a autonomia da mulher na assistência ao parto induzido. Método. Trata-se de um estudo transversal realizado no período de outubro de 2019 a junho de 2021 por meio da aplicação de um questionário eletrônico, construído no Google Forms, contendo questões fechadas. Resultados.  383 mulheres responderam ao questionário elaborado pelos autores. A idade das participantes variou entre 17 a 50 anos. Dentre as participantes, 28,8% tiveram o parto induzido, das quais 12,5% passaram pela indução mecânica, 62,5% receberam ocitocina e 25% prostaglandina/misoprostol. Conclusões. A autonomia da parturiente na condução do seu parto é primordial para que os profissionais atuem com boas práticas na assistência ao parto

The budget impact of monoclonal antibodies used to treat metastatic colorectal cancer in Minas Gerais, Brazil

Introduction: Biological medicines have increased the cost of cancer treatments, which also raises concerns about sustainability. In Brazil, three monoclonal antibodies (mAbs)—bevacizumab, cetuximab, and panitumumab—are indicated for the treatment of metastatic colorectal cancer (mCRC) but not currently funded by the Unified Health System (SUS). However, successful litigation has led to funding in some cases. Objective: Our objective was to evaluate the budgetary impact of including the mAbs bevacizumab, cetuximab, and panitumumab in standard chemotherapy for the treatment of mCRC within the SUS of Minas Gerais (MG), Brazil. Method: A budget impact analysis of incorporating mAbs as first-line treatment of mCRC in MG was explored. The perspective taken was that of the Brazilian SUS, and a 5-year time horizon was applied. Data were collected from lawsuits undertaken between January 2009 and December 2016, and the model was populated with data from national databases and published sources. Costs are expressed in $US. Results: In total, 351 lawsuits resulted in funding for first-line treatment with mAbs for mCRC. The three alternative scenarios analyzed resulted in cost increases of 348–395$US103,360,980 compared with the reference scenario over a 5-year time horizon, and bevacizumab and cetuximab had budgetary impacts of $US111,334,890 and 113,772,870, respectively. The use of the anti-epidermal growth factor receptor (EGFR) mAbs (cetuximab and panitumumab) is restricted to the approximately 41$US106 million. Conclusion: These results highlight the appreciable costs for incorporating bevacizumab, cetuximab, and panitumumab into the SUS. Appreciable discounts are likely to be necessary before incorporation of these mAbs is approved

Could Uranus and Neptune form by collisions of planetary embryos?

The origin of Uranus and Neptune remains a challenge for planet formation models. A potential explanation is that the planets formed from a population of a few planetary embryos with masses of a few Earth masses which formed beyond Saturn’s orbit and migrated inwards. These embryos can collide and merge to form Uranus and Neptune. In this work, we revisit this formation scenario and study the outcomes of such collisions using 3D hydrodynamical simulations. We investigate under what conditions the perfect-merging assumption is appropriate, and infer the planets’ final masses, obliquities, and rotation periods, as well as the presence of proto-satellite discs. We find that the total bound mass and obliquities of the planets formed in our simulations generally agree with N-body simulations therefore validating the perfect-merging assumption. The inferred obliquities, however, are typically different from those of Uranus and Neptune, and can be roughly matched only in a few cases. In addition, we find that in most cases, the planets formed in this scenario rotate faster than Uranus and Neptune, close to break-up speed, and have massive discs. We therefore conclude that forming Uranus and Neptune in this scenario is challenging, and further research is required. We suggest that future planet formation models should aim to explain the various physical properties of the planets such as their masses, compositions, obliquities, rotation rates, and satellite systems

Estudos da formação de planetas terrestres

O estudo da formação de planetas terrestres no Sistema Solar, é crucial para compre- endermos como outros sistemas planetários formam e também inferir as condições que poderiam ter influenciado a origem e evolução de vida na Terra. Esta Tese de douto- rado apresenta um estudo numérico da formação de planetas terrestres. Nosso objetivo principal é analisar o último estágio da formação desses planetas no Sistema Solar, em particular, a formação de Marte e a origem da água da Terra. Esses dois pontos têm intrigado cientistas ao longo de muitos anos. Enquanto que o planeta produzido ao redor de 1.5 UA é, em geral, muito mais massivo do que Marte, na grande parte das simulações, a origem da água da Terra é outro tema de intenso debate. Em vista disso, nós desenvol- vemos um cenário considerando uma depleção local de massa, no disco protoplanetário, a fim de analisarmos a origem da baixa massa de Marte, e também usamos um modelo composto para estudarmos a origem da água da Terra. Este trabalho apresenta um grande número de simulações numéricas explorando uma diversidade de parâmetros do sistema. Entre os principais podemos citar as variadas configurações de planetas gigantes, discos com diferentes perfis de densidade superficial de massa e modelos de distribuição de água. Nós também apresentamos um estudo dos efeitos de ressonâncias seculares nesses discos protoplanetários. Os principais resultados desses experimentos apontam a possibilidade da formação de planetas similares a Marte ao redor de 1.5 UA, especialmente, quando é considerado uma escala de depleção local, no disco protoplanetário, moderadamente alta (50-75%), localizada ao redor de 1.5 UA. Isto é observado juntamente com a formação de planetas do tipo Terra, em torno de 1 UA do Sol, com substanciais...The study of terrestrial planet formation in the Solar System is crucial to understand how other planetary systems form and to infer the conditions that favored the origin and evolution of life on Earth. In this Thesis we present a numerical study of the accretion of terrestrial planets. Our main goal is study the late stage of the terrestrial planet accretion in the Solar System, especially the formation of Mars and the origin of Earth’s water. These two points have intrigued scientists for many years. Whereas the planet formed around Mars’ semimajor axis is, in general, much more massive than Mars, the origin of Earth’s water is a matter of intense debate. In view of that, we have developed a scenario considering a local depletion in the density of the protosolar nebula in order to analyze the low mass of Mars, and also explored a compound model of water distribution to study the origin of Earth’s water. We have carried out extensive numerical simulations of the formation of terrestrial planets in protoplanetary disks exploring a large variety of parameters of the system, as different giant planet configurations, surface density profiles and water distribution models. We also have presented a study of the effects of secular resonances on the evolution of these protoplanetary disks. Our main results point to the possibility of the formation of Mars-sized bodies around 1.5 AU, especifically when is considered a scale of the disk local mass-depletion moderately high (50-75%) around 1.5 AU, as well as Earth-sized planets can form around 1 AU with substantial amount of water. Regarding the origin of Earth’s water, we find that the compound model incorporating both the principal endogenous and exogenous theories, play an important role by... (Complete abstract click electronic access below)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP