Hemeroteca del mes octubre, 2015

A toy quantum analog of enzymes

Por • 31 oct, 2015 • Category: Crítica

We present a quantum system incorporating qualitative aspects of enzyme action in which the possibility of quantum superposition of several conformations of the enzyme-substrate complex is investigated. We present numerical results showing quantum effects that transcend the case of a statistical mixture of conformations.

Topological Ramsey numbers and countable ordinals

Por • 30 oct, 2015 • Category: Educacion

We study the topological version of the partition calculus in the setting of countable ordinals. Let α and β be ordinals and let k be a positive integer. We write β→top(α,k)2 to mean that, for every red-blue coloring of the collection of 2-sized subsets of β , there is either a red-homogeneous set homeomorphic to α or a blue-homogeneous set of size k . The least such β is the topological Ramsey number Rtop(α,k) . We prove a topological version of the Erdos-Milner theorem, namely that Rtop(α,k) is countable whenever α is countable. More precisely, we prove that Rtop(ωωβ,k+1)≤ωωβ⋅k for all countable ordinals β and finite k .

Topological dynamics and the complexity of strong types

Por • 30 oct, 2015 • Category: Ambiente

We develop topological dynamics for the group of automorphisms of a monster model of any given theory. In particular, we find strong relationships between objects from topological dynamics (such as the generalized Bohr compactification introduced by Glasner) and various Galois groups of the theory in question, obtaining essentially new information about them, e.g. we present the closure of the identity in the Lascar Galois group of the theory as the quotient of a compact, Hausdorff group by a dense subgroup. We apply this to describe the complexity of bounded, invariant (not necessarily Borel) equivalence relations, obtaining comprehensive results, subsuming and extending the existing results and answering some open questions from earlier papers. We show that, in a countable theory, any such relation restricted to the set of realizations of a complete type over ∅ is type-definable if and only if it is smooth. Then we show a counterpart of this result for theories in an arbitrary (not necessarily countable) language, obtaining also new information involving relative definability of the relation in question.

Continuum as a primitive type

Por • 30 oct, 2015 • Category: Opinion

The paper is the revision and extended version of the Section 6 of the paper {\em Types and operations} arXiv:1501.03043. Here, primitive types (corresponding to the intuitive concept of Continuum) are introduced along with primitive operations, constructors, and relations.

The Insecure Future of the World Economic Growth

Por • 30 oct, 2015 • Category: Economía

Growth rate of the world Growth Domestic Product (GDP) is analysed to determine possible pathways of the future economic growth. The analysis is based on using the latest data of the World Bank and it reveals that the growth rate between 1960 and 2014 was following a trajectory approaching asymptotically a constant value. The most likely prediction is that the world economic growth will continue to increase exponentially, which over a sufficiently long time is unsustainable. A more optimistic but less realistic prediction is based on the assumption that the growth rate will start to decrease linearly. In this case, the world economic growth is predicted to reach a maximum, if the growth rate is going to decrease linearly with time, or to follow a logistic trajectory, if the growth rate is going to decrease linearly with the size of the world GDP.

Can we have another light (~ 145 GeV) Higgs boson?

Por • 30 oct, 2015 • Category: Leyes

A second light Higgs boson, with mass of approximately 145 GeV, is predicted by non-minimal Supersymmetric models. This new particle can account for an apparent \sim 3 \sigma excess recorded by the CMS experiment at the Large Hadron Collider (LHC) during Run 1. We show how this can be explained in a particular realisation of these scenarios, the (B-L) Supersymmetric Model (BLSSM), which also has other captivating features, like offering an explanation for neutrino masses and relieving the small hierarchy problem of the Minimal Supersymmetric Standard Model (MSSM).

Cuba and US Foreign Policy

Por • 28 oct, 2015 • Category: sociologia

It’s worth to note that STRATFOR experts use the example of Venezuela, the Cuban nearest and closest ally in the hemisphere, in their assessments of prospects for US-Cuba relationship. They believe that ultimately the Venezuela’s future will rely on global oil prices and Venezuelan President Nicolas Maduro’s ability to simultaneously manage unrest on the streets and counter challengers within the government. In fact, several hours after the U.S.-Cuba prisoner swap was announced, Maduro publicly said Venezuela would be willing to improve its stagnant political ties with the United States.

Strategic Engineered Migration as Weapon of War

Por • 28 oct, 2015 • Category: Política

Who is providing guarantees that encourage hundreds of thousands of people to rush from other continents to Europe and why? What we are seeing now is the practical implementation of theoretical calculations of a strategic nature. Such strategies have been under development for a long time. One of them is a study by the Belfer Center for Science and International Affairs at Harvard University that bears the name «Strategic Engineered Migration as a Weapon of War», which the author also uses for the title of this article. The study was first published in 2008 in the Civil Wars journal. Using a combination of statistical data and case study analysis, the author of the work, Kelly Greenhill, provides answers to the following questions: can refugees be a specific type of weapon, can this weapon only be used in wartime or in peacetime as well, and just how successful can its exploitation be? On the whole, Greenhill answers these questions in the affirmative.

Policías en peligro

Por • 28 oct, 2015 • Category: Nacionales

Los venezolanos tienen miedo y restringen sus actividades normales por temor a ser víctimas

Heideggers Dinge

Por • 28 oct, 2015 • Category: Filosofía

This paper discusses the notion of a thing (Ding) in Heidegger. Its aim is to explain the systematic place of that notion in Heidegger’s thought in relation to his ontological discourse: as what is explained through different understandings of being, things allow for a simultaneous differentiation and discussion of the different epochs in the so-called history of being. Thus a phenomenology of things and thingness serves as frame of reference for all explications of ‘what there is.’ If Heidegger is a realist, it is not because he attributes reality to all that is, but rather because all explanations of being refer back to how things are discovered as meaningful.