El modelo de V453 Scorpii

El análisis de espectrogramas tomados en Córdoba, Mount Wilson y Lick, combinados con los datos disponibles de la fotometría, permite describir al sistema V453 Scorpii como formado por una estrella primaria de tipo B1 Iab y una secundaria de radio menor pero cuya masa es probablemente mayor y, en todo caso, del mismo orden de magnitud que la de otra estrella. Como se informó en el Boletín Nº4 el espectro de la estrella secundaria sólo muestra líneas de emisión, las cuales deben originarse en material que es eyectado por dicha estrella con simetría esférica. El comportamiento de los detalles espectrales sugiere la existencia de una corriente gaseosa desde la estrella B hacia la compañera (en la descripción que apareció en el Boletín Nº4 se ha deslizado un error) que puede ser la fuente de opacidad continua que afecta al espectro en ciertas fases del ciclo. El trabajo in extenso aparecerá en el número del 15 de febrero de 1965 del Astrophysical Journal.Asociación Argentina de Astronomí

El modelo de V453 Scorpii

El análisis de espectrogramas tomados en Córdoba, Mount Wilson y Lick, combinados con los datos disponibles de la fotometría, permite describir al sistema V453 Scorpii como formado por una estrella primaria de tipo B1 Iab y una secundaria de radio menor pero cuya masa es probablemente mayor y, en todo caso, del mismo orden de magnitud que la de otra estrella. Como se informó en el Boletín Nº4 el espectro de la estrella secundaria sólo muestra líneas de emisión, las cuales deben originarse en material que es eyectado por dicha estrella con simetría esférica. El comportamiento de los detalles espectrales sugiere la existencia de una corriente gaseosa desde la estrella B hacia la compañera (en la descripción que apareció en el Boletín Nº4 se ha deslizado un error) que puede ser la fuente de opacidad continua que afecta al espectro en ciertas fases del ciclo. El trabajo in extenso aparecerá en el número del 15 de febrero de 1965 del Astrophysical Journal.Asociación Argentina de Astronomí

El modelo de V453 Scorpii

El análisis de espectrogramas tomados en Córdoba, Mount Wilson y Lick, combinados con los datos disponibles de la fotometría, permite describir al sistema V453 Scorpii como formado por una estrella primaria de tipo B1 Iab y una secundaria de radio menor pero cuya masa es probablemente mayor y, en todo caso, del mismo orden de magnitud que la de otra estrella. Como se informó en el Boletín Nº4 el espectro de la estrella secundaria sólo muestra líneas de emisión, las cuales deben originarse en material que es eyectado por dicha estrella con simetría esférica. El comportamiento de los detalles espectrales sugiere la existencia de una corriente gaseosa desde la estrella B hacia la compañera (en la descripción que apareció en el Boletín Nº4 se ha deslizado un error) que puede ser la fuente de opacidad continua que afecta al espectro en ciertas fases del ciclo. El trabajo in extenso aparecerá en el número del 15 de febrero de 1965 del Astrophysical Journal.Asociación Argentina de Astronomí

Stability Analysis of a Hybrid Cellular Automaton Model of Cell Colony Growth

Cell colonies of bacteria, tumour cells and fungi, under nutrient limited growth conditions, exhibit complex branched growth patterns. In order to investigate this phenomenon we present a simple hybrid cellular automaton model of cell colony growth. In the model the growth of the colony is limited by a nutrient that is consumed by the cells and which inhibits cell division if it falls below a certain threshold. Using this model we have investigated how the nutrient consumption rate of the cells affects the growth dynamics of the colony. We found that for low consumption rates the colony takes on a Eden-like morphology, while for higher consumption rates the morphology of the colony is branched with a fractal geometry. These findings are in agreement with previous results, but the simplicity of the model presented here allows for a linear stability analysis of the system. By observing that the local growth of the colony is proportional to the flux of the nutrient we derive an approximate dispersion relation for the growth of the colony interface. This dispersion relation shows that the stability of the growth depends on how far the nutrient penetrates into the colony. For low nutrient consumption rates the penetration distance is large, which stabilises the growth, while for high consumption rates the penetration distance is small, which leads to unstable branched growth. When the penetration distance vanishes the dispersion relation is reduced to the one describing Laplacian growth without ultra-violet regularisation. The dispersion relation was verified by measuring how the average branch width depends on the consumption rate of the cells and shows good agreement between theory and simulations.Comment: 8 pages, 6 figure

Eclipsing Binaries Showing Light Time Effect

Four eclipsing binaries, which show apparent changes of period, have been studied with respect to a possible presence of the light time effect. With a least squares method we calculated new light elements of these systems, the mass function of the predicted third body, and its minimum mass. We discuss the probability of the presence of such bodies in terms of mass function, changes in radial velocity and third light in solution of light curves.Comment: 4 pages, 4 figures, 1 table, conference proceeding

Toiminimen kirjanpito

Opinnäytetyön tavoitteena oli selvittää mitä osaamista tarvitaan toiminimen kirjanpidon toteuttamiseen. Työn toimeksiantajana toimi tamperelainen hyvinvointialan yrittäjä, joka ei ole toiminnastaan alv-velvollinen. Työn tarkoituksena oli kouluttaa tekijä peruskirjanpidon hoitamiseen. Tarkoituksena oli, että toimeksiantajan kirjanpito sekä veroilmoituksen täyttäminen ovat vuodesta 2017 eteenpäin opinnäytetyön tekijän vastuulla. Työn teoriaosuudessa keskityttiin kirjanpidollisiin peruskäsitteisiin toimeksiantajan elinkeinotoiminnan luonne huomioiden. Verotuksen osuudessa keskityttiin yritystulon verottamiseen yleensä ja esiteltiin ammatinharjoittajan veroilmoitus siltä osin, kun se toimeksiantajan yritystoiminta huomioiden oli tarpeellista. Sen lisäksi, että tekijä perehdytti itsensä alusta alkaen kirjanpidon maailmaan, teki työstä työlään erityisesti edellisvuosien kirjanpitomateriaaliin tutustuminen, sopivan kirjanpito-ohjelman etsiminen ja juoksevan kirjanpidon suorittaminen. Opinnäyteyön tavoite toteutui, sillä työn tekijällä on nyt tarvittava osaaminen kirjanpito-ohjelman käyttämiseen sekä juoksevan kirjanpidon hoitamiseen. Kirjanpidollisiin perusasioihin keskittyminen oli työn tavoitteen toteutumisen kannalta tärkeää, sillä perustietoja kirjanpidosta tekijällä ei juurikaan ennestään ollut. Toimeksiantajan kirjanpito on tällä hetkellä toteutettuna Tappio kirjanpito-ohjelmaa käyttäen elokuun 2017 loppuun asti. Opinnäytetyön liitteenä on Tappio-ohjelmasta poimitut tuloslaskelma ja tase. Kirjaukset perustavat tapahtumiin, jotka ovat muodostuneet 31.8.2017 mennessä. Opinnäytetyötä varten lukuja on muunnettu. Työ ei suinkaan lopu raportin palauttamiseen. Juoksevaa kirjanpitoa jatketaan loppuvuoden osalta ja tilinpäätös tulee toteuttaa vuoden 2018 alussa todellisia tilikauden lukuja käyttäen. Toimeksiantaja on myös ulkoistanut veroilmoituksen täyttämisen tämän työn tekijälle. Prosessin myötä tekijän osaaminen toiminimen kirjanpidon hoitamiseen on kohonnut ammattimaiselle tasolle, joten kirjanpitopalvelua voi jatkossa tarjota myös muille toiminimiyrittäjille. Tekijä jatkaa osaamisen kartoitusta tutustumalla alv-kirjauksiin.The purpose of this thesis was to find out what skills are required to perform the accounting for a sole trader. The commissioner was a welfare entrepreneur who practices business in Tampere. The business is not liable to pay value added tax. The aim of the thesis was to give the author the capability to perform the commissioner´s accounting independently in the future. The theoretical part of the thesis focused on the basic bookkeeping concepts considering the nature of the commissioner´s business. The taxation section focused on the business income, and the tax return was presented, as it is necessary for the commissioner´s business. An essential part of the work process was to familiarize with the accounting material of the previous years, to find a suitable accounting program, and to perform the current bookkeeping. The author is now capable of using the accounting program and keeping the accounts until preparing the income statement and balance sheet. Thus the goal of the thesis was reached. The routine bookkeeping continues and the financial statements will be prepared at the end of the year. The author will also complete the tax return for the financial year of 2017. Because of the professional development, the author can provide bookkeeping services to other welfare entrepreneurs, too

Eclipsing Binaries with Possible Light-Time Effect

The period changes of six eclipsing binaries have been studied with focus on the light-time effect. With the least squares method we also calculated parameters of such an effect and properties of the unresolved body in these systems. With these results we discussed the probability of presence of such bodies in the systems with respect to possible confirmation by another method. In two systems we also suggested the hypothesis of fourth body or magnetic activity for explanation of the "second-order variability" after subtraction of the light-time effect of the third body.Comment: 4 pages, 1 figure, 2 tables, conference proceeding

On a diffuse interface model for tumour growth with non-local interactions and degenerate mobilities

We study a non-local variant of a diffuse interface model proposed by Hawkins--Darrud et al. (2012) for tumour growth in the presence of a chemical species acting as nutrient. The system consists of a Cahn--Hilliard equation coupled to a reaction-diffusion equation. For non-degenerate mobilities and smooth potentials, we derive well-posedness results, which are the non-local analogue of those obtained in Frigeri et al. (European J. Appl. Math. 2015). Furthermore, we establish existence of weak solutions for the case of degenerate mobilities and singular potentials, which serves to confine the order parameter to its physically relevant interval. Due to the non-local nature of the equations, under additional assumptions continuous dependence on initial data can also be shown.Comment: 28 page

Model for in vivo progression of tumors based on co-evolving cell population and vasculature

With countless biological details emerging from cancer experiments, there is a growing need for minimal mathematical models which simultaneously advance our understanding of single tumors and metastasis, provide patient-personalized predictions, whilst avoiding excessive hard-to-measure input parameters which complicate simulation, analysis and interpretation. Here we present a model built around a co-evolving resource network and cell population, yielding good agreement with primary tumors in a murine mammary cell line EMT6-HER2 model in BALB/c mice and with clinical metastasis data. Seeding data about the tumor and its vasculature from in vivo images, our model predicts corridors of future tumor growth behavior and intervention response. A scaling relation enables the estimation of a tumor's most likely evolution and pinpoints specific target sites to control growth. Our findings suggest that the clinically separate phenomena of individual tumor growth and metastasis can be viewed as mathematical copies of each other differentiated only by network structure

A new ghost cell/level set method for moving boundary problems:application to tumor growth

In this paper, we present a ghost cell/level set method for the evolution of interfaces whose normal velocity depend upon the solutions of linear and nonlinear quasi-steady reaction-diffusion equations with curvature-dependent boundary conditions. Our technique includes a ghost cell method that accurately discretizes normal derivative jump boundary conditions without smearing jumps in the tangential derivative; a new iterative method for solving linear and nonlinear quasi-steady reaction-diffusion equations; an adaptive discretization to compute the curvature and normal vectors; and a new discrete approximation to the Heaviside function. We present numerical examples that demonstrate better than 1.5-order convergence for problems where traditional ghost cell methods either fail to converge or attain at best sub-linear accuracy. We apply our techniques to a model of tumor growth in complex, heterogeneous tissues that consists of a nonlinear nutrient equation and a pressure equation with geometry-dependent jump boundary conditions. We simulate the growth of glioblastoma (an aggressive brain tumor) into a large, 1 cm square of brain tissue that includes heterogeneous nutrient delivery and varied biomechanical characteristics (white matter, gray matter, cerebrospinal fluid, and bone), and we observe growth morphologies that are highly dependent upon the variations of the tissue characteristics—an effect observed in real tumor growth