Spatial and observational homogeneities of the galaxy distribution in standard cosmologies

This work discusses the possible empirical verification of the geometrical concept of homogeneity of the standard relativistic cosmology considering its various definitions of distance. We study the physical consequences of the distinction between the usual concept of spatial homogeneity (SH), as defined by the Cosmological Principle, and the concept of observational homogeneity (OH), arguing that OH is in principle falsifiable by means of astronomical observations, whereas verifying SH is only possible indirectly. Simulated counts of cosmological sources are produced by means of a generalized number-distance expression that can be specialized to produce either the counts of the Einstein-de Sitter (EdS) cosmology, which has SH by construction, or other types of counts, which do, or do not, have OH by construction. Expressions for observational volumes and differential densities are derived with the various cosmological distance definitions in the EdS model. Simulated counts that have OH by construction do not always exhibit SH features. The reverse situation is also true. Besides, simulated counts with no OH features at low redshift start showing OH characteristics at high redshift. The comoving distance seems to be the only distance definition where both SH and OH appear simultaneously. The results show that observations indicating possible lack of OH do not necessarily falsify the standard Friedmannian cosmology, meaning that this cosmology will not necessarily always produce observable homogeneous densities. The general conclusion is that the use of different cosmological distances in the characterization of the galaxy distribution lead to significant ambiguities in reaching conclusions about the behavior of the large-scale galaxy distribution in the Universe.Comment: 12 pages, 12 figures, LaTeX. Matches the final version sent to the journal. Accepted for publication in "Astronomy and Astrophysics

A Fortran Code for Null Geodesic Solutions in the Lemaitre-Tolman-Bondi Spacetime

This paper describes the Fortran 77 code SIMU, version 1.1, designed for numerical simulations of observational relations along the past null geodesic in the Lemaitre-Tolman-Bondi (LTB) spacetime. SIMU aims at finding scale invariant solutions of the average density, but due to its full modularity it can be easily adapted to any application which requires LTB's null geodesic solutions. In version 1.1 the numerical output can be read by the GNUPLOT plotting package to produce a fully graphical output, although other plotting routines can be easily adapted. Details of the code's subroutines are discussed, and an example of its output is shown.Comment: 13 pages, 10 figures, LaTeX. Fortran code included with the LaTeX source code (also available at http://www.if.ufrj.br/~mbr/codes). Accepted for publication in "Computer Physics Communications

How mortality patterns have changed in Portugal

Changes in social structures, advances in medicine and technology highly contributed to life expectancy increase across the entire world. Thus, longevity’s increase occurs as a result of significant improvements in health and consequent reductions in mortality rates. Past high levels of mortality are now experienced later in life, suggesting that senescence is being delayed and not stretched and individuals are reaching older ages in better physiological condition (Vaupel, 2010). Following the Human Mortality Database (HMD - http://www.mortality.org), life expectancy at birth in Portugal was, in 2015, 81.12 years (78.02 for males and 84.02 for females)

Skeptical Fideism in Cicero’s De Natura Deorum

The work of Richard H. Popkin both introduced the concept of skeptical fideism and served to impressively document its importance in the philosophies of a diverse range of thinkers, including Montaigne, Pascal, Huet, and Bayle. Popkin’s landmark History of Scepticism, however, begins its coverage with the Renaissance. In this paper I explore the roots of skeptical fideism in ancient Greek and Roman philosophy, with special attention to Cicero’s De Natura Deorum, the oldest surviving text to clearly develop a skeptical fideist perspective

Cancer mortality in Portugal

Following Population News, Trends and Attitudes #6 it was possible to identify that, despite circulatory system diseases represent the leading causes of death (COD) in Portugal, the share of deaths caused by neoplasms is increasing with time. Analysing data from 10th International Classification of Diseases available at Statistics Portugal (INE), one can observe that since 2010 mortality associated to neoplasms is the major COD for males. In 2015, males presented almost twice the number of deaths caused by neoplasms when compared to females: 356.0 against 169.9 per 100.000 individuals

What do Portuguese people die of?

Nowadays, in developed countries as Portugal, deaths are essentially concentrated at old and very old ages, but it is still rather important to identify main causes of death (CODs). Thus, following Population News, Trends and Attitudes #1, where it was evaluated how mortality patterns have changed In Portugal, i.e., how mortality rates declined over time, it is also imperative to understand from what Portuguese inhabitants are dying of

The Theistic Argument from Beauty: A Philonian Critique

In this paper I consider an understudied form of the design argument which focuses on the beauty of the natural world and which argues, on that basis, that the world requires a divine Artist in order to explain its beauty. Against this view, one might raise a question concerning the beauty of, and in, this divine Artist. What explains the divine beauty? This kind of explanatory regress objection is exactly like that used by Philo in Hume’s Dialogues to undercut standard versions of the design argument focused on the orderliness of the world. Here I argue that Philo’s explanatory regress objection likewise significantly undercuts versions of the design argument focusing on the beauty of the world