An alternative singularity-free cosmological scenario from cusp geometries

We study an alternative geometrical approach on the problem of classical cosmological singularity. It is based on a generalized function $f (x, y) = x^{2} + y^{2} = (1 - z)z^{n}$ which consists of a cusped coupled isosurface. Such a geometry is computed and discussed into the context of Friedmann singularity-free cosmology where a pre-big bang scenario is considered. Assuming that the mechanism of cusp formation is described by non-linear oscillations of a pre-big bang extended very high energy density field ($> 3 \times 10^{94} kg/m^{3}$), we show that the action under the gravitational field follows a tautochrone of revolution, understood here as the primary projected geometry that alternatively replaces the Friedmann singularity in the standard big bang theory. As shown here this new approach allows us to interpret the nature of both matter and dark energy from first geometric principles.Comment: Proceedings of Sixth International School on Field Theory and Gravitation-2012 - by American Institute of Physic

Ultramafic rocks serpentinization and metasomatism : discussion of their characteristics and recomendations for geochemical treatment

Este artigo procura fazer uma revisão geral sobre os aspectos petroquímicos das modificações metamórficas das rochas ultramáficas. A princípio, por meio da revisão, tomou-se possível distinguir os mecanismos pelos quais a transferência de massa é efetuada: difusão intergranular e transporte por solução são os termos extremos cuja importância relativa depende da quantidade de água disponível e em circulação no sistema. As condições geológicas nas quais esta transferência de massa ocorre são descritas como contato/justaposição, ou como infiltração, e exemplos disponíveis na literatura são apresentados. As feições geológicas usadas para reconhecer os mecanismos e as condições geológicas da transferência de massa incluem a zonação metassomática, estruturas, mobilidade dos compo nentes químicos, estabilidade das fases minerais etc, e elas são apresentadas e discutidas, ou apenas referidas no texto. Ao final, baseado nos resultados de investigações experimentais, é desenvolvido um método para verificar quais componentes químicos foram transferidos durante a serpentinização e o metassomatismo das rochas ultramáficas. O método procura pôr em evidência os elementos que não desenvolvem gradientes de potencial químico.This paper intends a general revision about the petrochemical aspects of the ultramafic rocks metamorphic modification. At first, the extreme mechanisms of mass transfer is distinguished: intergranular diffusion and transport by solution; their relative importance depends on the water content of the system. The geological conditions in which the mass transfer occurs are described as contact/juxtaposition, or as infiltration, and available literature examples are also presented. The geological features used to recognize the mechanisms and the conditions of the mass transfer include metasomatic zoning, structures, chemical components mobility, mineral phase stability etc, and they are discussed in the paper. At last, based on the results of experimental investigations, a method is developed to verify which chemical components were transfered during the serpentinization and metasomatism of the ultramafic rocks. The method is developed to put in evidence the elements that do not develop chemical potencial gradient

Confidence in Causal Inference under Structure Uncertainty in Linear Causal Models with Equal Variances

Inferring the effect of interventions within complex systems is a fundamental problem of statistics. A widely studied approach employs structural causal models that postulate noisy functional relations among a set of interacting variables. The underlying causal structure is then naturally represented by a directed graph whose edges indicate direct causal dependencies. In a recent line of work, additional assumptions on the causal models have been shown to render this causal graph identifiable from observational data alone. One example is the assumption of linear causal relations with equal error variances that we will take up in this work. When the graph structure is known, classical methods may be used for calculating estimates and confidence intervals for causal effects. However, in many applications, expert knowledge that provides an a priori valid causal structure is not available. Lacking alternatives, a commonly used two-step approach first learns a graph and then treats the graph as known in inference. This, however, yields confidence intervals that are overly optimistic and fail to account for the data-driven model choice. We argue that to draw reliable conclusions, it is necessary to incorporate the remaining uncertainty about the underlying causal structure in confidence statements about causal effects. To address this issue, we present a framework based on test inversion that allows us to give confidence regions for total causal effects that capture both sources of uncertainty: causal structure and numerical size of nonzero effects

INCLUSÃO ESCOLAR: POSSIBILIDADES DE FIRMAR A DIGNIDADE HUMANA PELA VERTENTE DO TERCEIRO INCLUÍDO

O trabalho é uma reflexão com base nos estudos realizados, nos últimos três anos, sobre a temática da inclusão escolar. Trata-se de um tema desejado por muitos, sejam governantes, sejam docentes e também alunos. Porém, sua prática efetiva é ainda um sonho distante. O que os três estudos desenvolvidos nos permitiram reconhecer é a necessidade de uma profunda mudança de mentalidade em relação ao fazer escola e fazer sociedade. Particularmente, em relação ao fazer pedagógico é fundamental superar a lógica transmissiva. Em seu lugar precisa vicejar uma concepção e prática escolar de relações humanas. Conceber e efetivar uma sala de aula na qual o tratamento relacional entre professor e aluno esteja alicerçado no cuidado, na entreajuda e na construção de convivências. Com essa perspectiva apresentamos uma nova proposta de estudos com a temática originária da complexidade e no contexto da transdisciplinaridade e, mais especificamente o Terceiro Incluído. Como problemática dessa investigação questionamos: É possível, e como, a lógica do terceiro incluído potencializar mudanças de mentalidade e de atitudes de aceitação do outro diferente e estranho, transformando o sonho da educação inclusiva em convivências inclusivas? Assim, o objetivo desse novo estudo é investigar se e como a lógica do Terceiro Incluído, ao reconhecer a presença da complexidade, na emergente percepção das realidades, acena para a substituição da conjunção “ou”, e a certeza da expressão de que “dois corpos não podem ocupar a mesma região no espaço”, para a conjunção “e” e a expressão “ao mesmo tempo”

Preocupações e perspectivas da abordaem CTS : o caso das pesquisas publicadas na reec

Nos últimos anos, é crescente o interesse e as preocupações com abordagens CTS no contexto educacional. Esse panorama mais recente, contudo, vêm apresentando novas características, atribuindo diferentes significados para essas abordagens. Para buscar compreender e acompanhar esse movimento, a presente investigação tem como objetivo identificar e caracterizar as diferentes tendências e perspectivas CTS presentes no Ensino de Ciências. Para tanto, foi utilizado como objeto de estudo, a produção CTS publicada na Revista Electrónica de Enseñanza de las Ciencias. Foram analisados três aspectos diferentes, que dizem respeito aos objetivos propostos para as abordagens CTS, às ênfases adotadas e às preocupações educacionais implícitas. Pretende-se contribuir para um maior diálogo entre os pesquisadores e educadores que se propõem a trabalhar nessa perspectiva

Kartalla!-projekti : sanojen avulla parempaan arkeen

Opinnäytetyössä tarkastellaan Kartalla!-projektia, jonka tarkoituksena oli tarjota terapeuttista ja voimauttavaa sanataidetoimintaa keskisuomalaisille nuorille. Projektin kohderyhmässä oli sekä syrjäytymisvaarassa olevia että jo psykiatrisen hoidon piirissä olevia nuoria, mutta mukana oli myös ns. tavallisia, yläkouluikäisiä nuoria. Projektin tavoitteet olivat kuitenkin yhtä lailla sekä auttavassa että ennaltaehkäisevässä toiminnassa. Projektin toteuttamista varten koottiin moniammatillinen työryhmä, johon kuului kirjallisuusterapiaohjaajia, sanataideohjaajia, toimintaterapeutti sekä tarinateatteri-/psykodraamaohjaaja.Projektin pilottivaihe, johon opinnäytetyö keskittyy, kesti syksystä 2008 syksyyn 2009. Tänä aikana nuorten ryhmiä perustettiin Suomen Kulttuurirahaston Myrsky-hankkeen myöntämän rahoituksen kautta kuusi, joista viisi kuului opinnäytetyön tarkastelun piiriin. Ryhmille tarjottiin kerhotoiminnan tapaisesti sanataidetoimintaa, ja kevään ja kesän 2009 aikana kullakin ryhmällä oli pääsääntöisesti 10 tapaamiskertaa. Opinnäytetyön tarkoituksena oli tarkastella projektin toimivuutta käytännön ja hallinnon tasolla sekä kerätä nuorten kokemuksia projektista. Tutkimusmenetelminä käytettiin haastattelua ja kyselyä, joiden kohteina olivat ryhmissä käyneet nuoret, ohjaajat, projektikoordinaattori sekä eri yhteistyötahot, joiden kautta nuorten ryhmät muodostuivat. Kerätyn aineiston perusteella nuorten kokemukset projektista olivat pääosin positiivisia ja projektin jatkumista ja pidempää kestoa toivottiin. Työtavoissa ei myöskään ollut huomauttamista. Kuitenkin erityisesti ohjaajat kokivat projektin hallinnon ja koordinoinnin toimivuudessa olleen puutteita. Tiedotus ei ollut toiminut tehokkaimmalla mahdollisella tavalla ja muutenkin projektiin toivottiin selkeämpää rakennetta. Haasteellisena koettiin myös kohderyhmään kuuluvien nuorten tavoittaminen ja toimintaan innostaminen. Projektin voidaan kuitenkin sanoa ainakin osittain onnistuneen tavoitteessaan, sanojen antamisessa nuorille omien ongelmien ja ajatusten käsittelyyn.This thesis examines the Kartalla! -project. The purpose of the project was to offer young people in central Finland therapeutic and empowering activities through literary art. The target group of the project consisted of young people in danger of isolation and of young people already undergoing psychiatric treatment. So-called normal, middle-school aged people were also involved. The goals of the project were, however, concerned with both helping the young people as well as preventing isolation. A multi-vocational team was put together for carrying out the project. The team involved, for example, instructors of literary therapy and literary art, an occupational therapist and an instructor of playback theatre and psychodrama. The pilot phase of the project, which this thesis particularly concentrates on, lasted from the autumn of 2008 until the autumn of 2009. During this time, with the funding provided by the Myrsky-project of the Finnish Cultural Foundation, altogether six youth groups were established. Out of these, five were included under the observation of this thesis. The groups were offered literary art activities in the manner of clubs. During the spring and the summer of 2009 each group met in general ten times. The purpose of the thesis was to examine how the project functioned on the practical and the administrative level. It also gathered the young people's opinions on the project. Interviews and questionnaires were used as the research method. The targets of these were the young people that attended the groups, the instructors, the project coordinator and the different partnerships through which the groups of young people were formed. According to the gathered data, the experiences the young people had of the project were primarily positive. Continuation and a longer duration of the project were wished for. Moreover, there was no criticism towards the approaches to work. However, especially the instructors felt that there were lacks in the functionality of the project. Information had not worked as efficiently as possible, and there was a need for a clearer structure of the project. Reaching and motivating the targeted groups of young people was also seen as a challenge. However, in giving the young people the words to deal their own problems and thoughts with, it can be stated that the project at least partially succeeded in meeting its goals

Discussion of "A note on universal inference" by Timmy Tse and Anthony Davison

Invited discussion for Stat of "A note on universal inference" by Timmy Tse and Anthony Davison (2022

Rank-Based Causal Discovery for Post-Nonlinear Models

Learning causal relationships from empirical observations is a central task in scientific research. A common method is to employ structural causal models that postulate noisy functional relations among a set of interacting variables. To ensure unique identifiability of causal directions, researchers consider restricted subclasses of structural causal models. Post-nonlinear (PNL) causal models constitute one of the most flexible options for such restricted subclasses, containing in particular the popular additive noise models as a further subclass. However, learning PNL models is not well studied beyond the bivariate case. The existing methods learn non-linear functional relations by minimizing residual dependencies and subsequently test independence from residuals to determine causal orientations. However, these methods can be prone to overfitting and, thus, difficult to tune appropriately in practice. As an alternative, we propose a new approach for PNL causal discovery that uses rank-based methods to estimate the functional parameters. This new approach exploits natural invariances of PNL models and disentangles the estimation of the non-linear functions from the independence tests used to find causal orientations. We prove consistency of our method and validate our results in numerical experiments.Comment: Accepted for the 26th International Conference on Artificial Intelligence and Statistics (AISTATS) 202

Testing normality in any dimension by Fourier methods in a multivariate Stein equation

We study a novel class of affine-invariant and consistent tests for multivariate normality. The tests are based on a characterization of the standard d-variate normal distribution by way of the unique solution of an initial value problem connected to a partial differential equation, which is motivated by a multivariate Stein equation. The test criterion is a suitably weighted L2-statistic. We derive the limit distribution of the test statistic under the null hypothesis as well as under contiguous and fixed alternatives to normality. A consistent estimator of the limiting variance under fixed alternatives, as well as an asymptotic confidence interval of the distance of an underlying alternative with respect to the multivariate normal law, is derived. In simulation studies, we show that the tests are strong in comparison with prominent competitors and that the empirical coverage rate of the asymptotic confidence interval converges to the nominal level. We present a real data example and also outline topics for further research