Star clusters and the structure of the ISM. Tunnels and wakes in giant extragalactic HII regions

Several structures have been discovered embedded in regions of recent or ongoing star formation, which point to the importance of the interaction between fast moving wind-blowing stars and their environment. Using hydrodynamic simulations, we investigate the passage through the interstellar medium of a supersonic stellar wind source, and show how it can naturally lead to the formation of tubes, channels and swamps of globules as interfaces are crossed. The results are in excellent agreement with observation of 30 Doradus.Comment: 12 pages + 5 figures (GIF format) - Accepted for pub. in Astrophys. J. Letter

On the ongoing multiple blowout in NGC 604

Several facts regarding the structure of NGC 604 are examined here. The three main cavities, produced by the mechanical energy from massive stars which in NGC 604 are spread over a volume of 10$^6$ pc$^3$, are shown here to be undergoing blowout into the halo of M33. High resolution long slit spectroscopy is used to track the impact from massive stars while HST archive data is used to display the asymmetry of the nebula. NGC 604 is found to be a collection of photoionized filaments and sections of shells in direct contact with the thermalized matter ejected by massive stars. The multiple blowout events presently drain the energy injected by massive stars and thus the densest photoionized gas is found almost at rest and is expected to suffer a slow evolution.Comment: 15 pages (11 text), 4 figures. To be published in Ap

Sharedoubt: aplicación android para debatir y compartir dudas dentro de una comunidad de estudiantes

Treballs Finals de Grau d'Enginyeria Informàtica, Facultat de Matemàtiques, Universitat de Barcelona, Any: 2018, Director: Sergio Sayago Barrantes[en] It is widely known that digital technologies are having a large impact on our daily lives, especially smartphones, which have become an essential technology for performing everyday activities. Hence, exists many apps designed to enrich and make our lives easier. This project presents the conceptualization, design and development of ShareDoubt, an app for helping students of the degree of CS at University of Barcelona to share doubts and enrich their educational experience at university. ShareDoubt tries to address one of the limitations of the Campus Virtual tool facilitated by the university: students do not use the forums despite being willing to share doubts online with their classmates. Therefore, the main objective is to create a students’ community where, through the anonymity, all kind of doubts can be shared while doing the labs and preparing the exams. In this way, the participation of other users is encouraged, allowing the generation of different discussions from one doubt. These discussions can result in collective learning, enriching the knowledge of students. For the creation of this community, an app for Android smartphones has been developed following an incremental work methodology, putting in practice what has been learned during the degree. The app has been evaluated with students in an iterative way. The results show that the app is useful and easy to use

On the formation of massive stellar clusters

Here we model a star forming factory in which the continuous creation of stars results in a highly concentrated, massive (globular cluster-like) stellar system. We show that under very general conditions a large-scale gravitational instability in the ISM, which triggers the collapse of a massive cloud, leads with the aid of a spontaneous first generation of massive stars, to a standing, small-radius, cold and dense shell. Eventually, as more of the collapsing matter is processed and incorporated, the shell becomes gravitationally unstable and begins to fragment, allowing the formation of new stars, while keeping its location. This is due to a detailed balance established between the ram pressure from the collapsing cloud which, together with the gravitational force exerted on the shell by the forming cluster, acts against the mechanical energy deposited by the collection of new stars. We analyze the mass spectrum of fragments that result from the continuous fragmentation of the standing shell and show that its shape is well approximated at the high mass end by a power law with slope -2.25, very close to the value that fits the universal IMF. The self-contamination resultant from the continuous generation of stars is shown to lead to a large metal spread in massive ($\sim$ 10$^6$ M$_\odot$) clusters, while clusters with a mass similar to 10$^5$ M$_\odot$ or smaller, simply reflect the initial metalicity of the collapsing cloud. This is in good agreement with the data available for globular clusters in the Galaxy.Comment: 9 pages, 8 postscript figures - change of the address #3; - Sect. 2.2. paragraph 2: second sentence removed, third sentence change

DFT Calculations and Statistical Mechanics Applied to Isomerization of Pseudosaccharins

In the present work, molar fractions were obtained as a function of temperature with different levels of theory for the most representative isomers of three systems belonging to the family of pseudosaccharins. The choice of those three systems was due to the fact that it is known in the scientific literature that these systems present very small differences in their relative energies which make a complicated experimental characterization, in addition these compounds are of interest in the biological area. These systems represent challenges not only from an experimental point of view but also from a theoretical point of view. From the theoretical perspective, this study is also complicated since several possible isomers with very similar energies are presented. The diagrams of species distribution (molar fractions) provide information that cannot be accessed through the electronic structure calculations at T = 0. Here, this tool was useful to identify the most probable isomer from several quasi-degenerate isomers and to discern if thermal effects favor any of them, as well as to find trends despite the different results of each level of theory. Additionally, an analysis was performed on vibrational, rotational and electronic data in order to know the reason of the behavior of molar fractions as function of temperature

Diseño y construcción de un prototipo de un sistema de estabilización de un Motocultor.

Se ha diseñado y construido el prototipo de estabilización para un motocultor para zona andina, con la finalidad de reducir los riesgos de vuelco que se genera al transitar por superficies de alta pendientes, y aumentar la productividad en dichas zonas. Esto se debe al desplazamiento de la línea de acción del centro de gravedad de la máquina. Para lograr controlar esto se ha investigado y estudiado los diferentes diseños de los modelos y tipos de marcas existentes en el mercado. En el software SOLIDWORD se realizó el diseño y la modelación del prototipo. El análisis de esfuerzos del conjunto del brazo mecánico fue estático e intervinieron variables como el peso, fuerza de impacto, ángulo de inclinación, etc. Con la ayuda del software ANSYS 15.0 se pudo validar el diseño. Mientras que el diseño de los ejes de transmisión se los realizo mediante un análisis a fatiga para una potencia de 10 hp a 30 RPM. El control de la inclinación del prototipo es electrónico, mediante un sensor de inclinación (giroscopio), un micro controlador, y cilindros hidráulicos de doble efecto. Con la implementación de este sistema se alcanza la posibilidad de trabajar en superficies con elevadas pendientes logrado incrementar la producción agrícola en este tipo de terrenos. Se recomienda además que antes de poner en funcionamiento el sistema, se debe verificar los niveles óptimos de los fluidos. Y no se debe sobre pasar del máximo valor de inclinación para cual está diseñado el sistema de estabilización del motocultor.A stabilization prototype for a tiller to be used in the Andean region was designed and built in order to reduce the overturning risks generated when running steep surfaces as well as increasing the productivity of the area. This is due to the movement of the working line out of the gravitational point of the machine. To control is problem, it has been necessary to investigate and study the different models design and the existing brands in the marked. By using SOLIDWORKS software the prototype was modeled and designed. The effort analysis of the mechanic arm was static where variables such as: weight, impact, and tilt angle were present. Whit the use of ANSYS 15.0 software the design was validated. While the of the transmission axis was carried out through a 10 hp at 30 RPM fatigue analysis the tilt control of the prototype is electronic whit a tilt sensor (gyroscope), a micro controller, and dual-effect hydraulic cylinders. Whit the implementation of this system it is possible to work in steep surfaces increasing in this way the Agricultural production on this type of land. It is recommended to implement the system verifying the optimal fluids level and it must not exceed the maximum tilt value for which the stabilization system of the tiller is designed

Reactivity Indexes and Structure of Fullerenes

The discovery of fullerenes and their production in measurable quantities launched many studies about their reactivity and possible applications. Their peculiar structure opened possibilities for their study, initially replacing carbon atoms with alternative atoms. The surface also offers the possibility of attaching several species and the interior of their hollow structure represents a challenge because of the possibility of confining elements or molecules that may become less stable when attached to the exterior of the cage. These modifications may considerably affect both chemical and physical properties. In this chapter, we propose the encapsulation of 3–10 nitrogen atoms as aggregates inside the C70 cage. We also study the structures and reactivity indexes and the stabilization conferred as a result of being part of the fullerene. These aggregates are mainly of interest because of their possible application as energetic materials

De la responsabilidad demostrada en las funciones misionales de la Registraduría Nacional del Estado Civil: hacia un programa de gestión de datos personales y la consolidación de un buen gobierno corporativo en el tratamiento de esa clase de información

Divulgação dos SUMÁRIOS das obras recentemente incorporadas ao acervo da Biblioteca Ministro Oscar Saraiva do STJ. Em respeito à Lei de Direitos Autorais, não disponibilizamos a obra na íntegra.Localização na estante: 342.721:347.961 R389

Altered excitatory-inhibitory balance within somatosensory cortex is associated with enhanced plasticity and pain sensitivity in a mouse model of multiple sclerosis

S1 IHC in pre-symptomatic and clinical-onset EAE: PV+ cell counts, PNN counts, and Iba-1+ microglia counts. A) Representative fluorescence photomicrographs of PV+ staining (low-mag) in S1 from control (CFA) and EAE animals at the pre-symptomatic stage (7–9 dpi PRE) or clinical onset (ONS). B) Group mean (±S.E.) total PV+ cell counts from S1HL of CFA (n = 8), PRE (n = 4), and ONS (n = 4) EAE animals. No significant differences were observed between groups (one-way ANOVA N.S.). C) Representative fluorescence photomicrographs of WFA+ staining (PNNs) in S1 from control (CFA) and EAE animals at the pre-symptomatic stage (7–9 dpi PRE) or clinical onset (ONS). D) Group mean (±S.E.) total PNN counts from S1HL of CFA (n = 11), PRE (n = 4), and ONS (n = 8) EAE animals. EAE animals exhibited significantly reduced PNN-counts vs. CFA-controls at clinical onset (one-way ANOVA, p = 0.007, post hoc comparisons vs. CFA-controls by Dunnett’s method). E) Representative fluorescence photomicrographs of Iba-1+ staining (PNNs) in S1 from control (CFA) and EAE animals at the pre-symptomatic stage (7–9 dpi PRE) or clinical onset (ONS). F) Group mean (±S.E.) total Iba-1+ counts from S1HL of CFA (n = 13), PRE (n = 4), and ONS (n = 8) EAE animals. EAE animals exhibited significantly increased numbers of Iba-1+ cells (microglial activation) in S1HL vs. CFA-controls at all time points (one-way ANOVA, p = 0.012, post hoc comparisons vs. CFA-controls by Dunnett’s method). (PDF 6418 kb

Algunos aportes de la ciencia y la fe ante la COVID-19

Este documento es el resumen del diálogo celebrado en la Universidad de Costa Rica como parte del proyecto de investigación sobre la interacción entre ciencia y religión en la universidad. Se presentan los aportes de un filósofo, un pastor cristiano y un biólogo genetista.Red para el Diálogo entre Ciencia y Religión, Universidad de Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Sociales::Facultad de Educación::Escuela de Educación Físic