Intertwining Symmetry Algebras of Quantum Superintegrable Systems

We present an algebraic study of a kind of quantum systems belonging to a family of superintegrable Hamiltonian systems in terms of shape-invariant intertwinig operators, that span pairs of Lie algebras like $(su(n),so(2n))$ or $(su(p,q),so(2p,2q))$. The eigenstates of the associated Hamiltonian hierarchies belong to unitary representations of these algebras. It is shown that these intertwining operators, related with separable coordinates for the system, are very useful to determine eigenvalues and eigenfunctions of the Hamiltonians in the hierarchy. An study of the corresponding superintegrable classical systems is also included for the sake of completness

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Realismo selectivo: ¿un programa de investigación regresivo?

El realismo selectivo (RS) es la versión del realismo científico preponderante en nuestros días, y de hecho la única versión del realismo defendible después de las críticas de Laudan basadas en la llamada inducción pesimista. RS sostiene que (i) las predicciones observacionales novedosas (e.g. que la teoría no se ha diseñado con la intención de realizarlas) y exitosas de una teoría se deben a que aquella parte del contenido inobservable de la teoría que es responsable de la predicción exitosa es (aproximadamente) verdadero, y (ii) las teorías posteriores que la suceden retienen (aproximadamente) dicha parte del contenido teórico. RS es una tesis empírica, y por tanto debe ser verificada o falsada por la historia de la ciencia. En este trabajo repasaremos los principales versiones de RS y sus principales anomalías históricas.Universidad de Málaga. Campus de Excelencia Internacional Andalucia Tech

Platform price parity clauses and market segmentation

Price parity clauses (PPCs) are widely adopted by online platforms to force client sellers not to lower their prices elsewhere. We investigate under what conditions online travel agencies (OTAs) decide to apply PPCs, and how this affects hotels' listing decisions on OTAs. We find OTAs adopt PPCs when there is a sufficiently large competitive pressure in the market, either between OTAs, or between hotels (or both). PPCs allow OTAs to charge higher commission fees to hotels, which can respond by delisting from certain OTAs, thereby segmenting the market. We also find that consumers and hotels generally lose out with PPCs

How to achieve full electrification: Lessons from Latin America

Electricity coverage in Latin America has increased substantially in recent decades, rising from 50% of the population in 1970 to more than 95% in 2015. Growth, however, slowed in the 1990s as many countries experienced difficulties in extending their networks further, in particular to serve those living in isolated and rural areas. In spite of this, the process of electrification was not interrupted and at the beginning of the 2010s decade most countries in the region were able to provide access to electricity to almost all of their populations. In this paper, we examine the main strategies used in Latin America to increase coverage and argue that only a combination of policy efforts has made it possible to achieve the current situation. We also examine the remaining obstacles, at policy and institutional levels, to achieving full coverage

Simplified Microbial Mats: Unraveling a complex community one alga at a time.

Microbial mats are the oldest known ecosystems with an over 3.4 billion-year fossil record. Understanding their structure and function will help us better understand the biological evolution of life on early earth. They are rich in diversity (phylogenetically and physiologically) ranking amongst the most complex systems on earth. In this investigation, we aim to develop an effective method to study microbial mat organisms in relatively uncomplicated ecosystems that mimic the way they grow in nature. By growing “simplified microbial mats” on polypropylene cloth, we are able to observe the range of biogeochemical processes of a single species in a biogeochemical setting that approximates in situ conditions. We are measuring the rate of nutrient consumption, specifically nitrate and phosphate, and hydrogen production, in order to determine if these “simple mats” are behaving as they would in nature. Pulse amplitude modulation (PAM) fluorometer data is recorded daily for regular observations of photosynthetic efficiency of each sample. Overall growth is documented using a digital SLR camera. In addition, microscopic photographs are taken to observe exactly how these organisms are growing and using the polypropylene cloth as a substrate