Effects of GIMP Retinex Filtering Evaluated by the Image Entropy

A GIMP Retinex filtering can be used for enhancing images, with good results on foggy images, as recently discussed. Since this filter has some parameters that can be adjusted to optimize the output image, several approaches can be decided according to desired results. Here, as a criterion for optimizing the filtering parameters, we consider the maximization of the image entropy. We use, besides the Shannon entropy, also a generalized entropy.Comment: Keywords: Image Processing, Foggy Images, Retinex, Shannon Entropy, Generalized Entropies, Kaniadakis Entrop

A tour about Isaac Newton's life

Here we propose a tour about the life of Isaac Newton, using a georeferenced method, based on the free satellite maps. Our tour is modelled on the time-line of the great scientist's life, as an ancient "itinerarium" was modelled on the Roman roads, providing a listing of places and intervening distances, sometimes with short description or symbols concerning the places. KML language and Google Earth, with its Street View and 3D images are powerful tools to create this virtual tour.Comment: Georeferencing, Satellite Maps, KML, XML, Acme Mapper, History of Physic

Self frequency-locking of a chain of oscillators

The paper studies the vibrational modes of a slightly damped uniform chain, with n masses coupled by elastic forces. It will be shown that, for certain lengths of the chain, that is for certain values of n, the damping of one of the masses at a specific position in the chain is able to constrain the vibration of the system to oscillate at a specific frequency. The damped mass turns out to be a node of the chain, subdividing it in two parts. This node can be considered as the synchronization element of the two subchains. As a consequence the oscillating system of n-masses is self-locking to the synchronized frequency of its subchains

Moving Ice and Satellites: The Motion of Crevasses in Antarctica

Antarctica is a remote and hostile continent, the study of which is fundamental because of the role it has on oceans and Earth’s climate. Affected by the global warming phenomenon, Antarctica requires a constant monitoring of the status and motion of its ice. This monitoring can be achieved by means of satellites. Here we will show, by using Google Earth imagery, some evidence of the ice flows in this continent. In particular, we will discuss the motion of some surface features of the ice shelves, which can be considered as the surface expression of basal crevasses. We can measure the rate of their motion too

Remote Roman Fortifications: The Forts of the Kharga Oasis

Many of the Roman fortifications, built for the defense of the Empire, are still existing. We can find them distributed across the vast empire, in concentration on the borders, in the locations where it was required more authority and military control. Here we discuss the fortifications of the Kharga Oasis in Egypt. In particular, we will discuss the Qasr el-Baramoudy fort, threatened by the motion of the sand dunes

Using the κ-exponential to deform Gumbel and Gompertz probability distributions

Here we propose the use of the κ-exponential to deform Gumbel and the Gompertz distributions. The κ-exponential is a function of κ-statistics, a statistics which has been developed by G. Kaniadakis, Politecnico di Torino, in the framework of special relativity, and used for statistical analyses involving power law tailed distributions. The exponentiated κ-Gumbel function is also considered, to have a further deformation of the probability distribution

Roman Centuriation in Satellite Images

The satellite images of Google Earth can show us how the Roman divided the land in their colonies, according to the surveying system of Centuriation

The Seven Pillars of the House of Wisdom

In the Proverbs, Solomon tells that the House of Wisdom has seven pillars. According to ancient and medieval thinkers, these pillars are the seven dispositions that a person must have to become wiser. Besides this direct interpretation of the pillars, we can also find them used as allegorical symbols. For instance, the pillars can represent the foundational principles of a given discipline. And also, in the academies, the seven pillars of wisdom manifest themselves in the seven liberal arts, which had their origin in the thinking skills outlined by Plato in his Republic. Here, we propose a discussion on the pillars of the house of wisdom, from the book of James to the contemporary literature

Cardano Formula and Some Figurate Numbers

Here we apply the Cardano formula to obtain the sequence of the positive integers from the sequences of integer numbers described by the cubic function of n. Examples will be proposed concerning figurate numbers

Sialic acids and viruses

Let us study viruses and the role of sialic acids in their first step of reproduction, the attachment to cells. We begin our study with the help of the "Earth's virology course", created by Vincent Racaniello, with David Tuller and Gertrud U. Rey. The first virus that we will study is that of influenza A. Actually, "Earth's virology course" is a proper starting point for learning the mechanisms the virus uses to attach and enter the host cells. In the case of the influenza virus, its spike protein is used to attach the virion to sialic acid receptors of the host cells. Then, we will consider coronaviruses, with the help of literature about the role of sialic acids in their attachment by means of spike proteins. In fact, there are seven human coronavirus and they use sialic acid or angiotensin-converting enzyme 2 (ACE2) or other receptors or a combination of them. Let us review the literature to understand if Sars-Cov-2 virus can use sialic acid for the attachment to cells or not. Its main target is considered the ACE2 receptor. We will see that a study exists which detected that Sars-Cov-2 protein molecules can bind to heparan sulfate glycans in a sulfation-dependent manner