On the Extreme Positive Feedback Star-Forming Mode from Massive and Compact Superstar Clusters

The force of gravity acting within the volume occupied by young, compact and massive superstar clusters, is here shown to drive in situ all the matter deposited by winds and supernovae into several generations of star formation. These events are promoted by radiative cooling which drains the thermal energy of the ejected gas causing its accumulation to then rapidly exceed the gravitational instability criterion. A detailed account of the integrated ionizing radiation and mechanical luminosity as a function of time is here shown to lead to a new stationary solution. In this, the mass deposition rate $\dot M$, instead of causing a wind as in the adiabatic solution, turns into a positive feedback star-forming mode equal to the star formation rate. Some of the implications of this extreme positive feedback mode are discussed.Comment: 4 pages, 4 figures, accepted for publication in The Astrophysical Journal Letter

The role of specific heat capacity on building energy performance and thermal discomfort

The key role of the building and construction sector, in terms of sustainability and decarbonization, has led building codes to tighten mandatory requirements related to buildings energy performance. Envelope quality, beyond light efficiency or the renewable energy contribution, is a key factor since the highest percentage of energy consumption is produced by thermal losses through enclosures. Therefore, building codes have significantly increased the mandatory benchmarks for equivalent thermal transmittance. However, the specific heat capacity (SHC) has commonly been overlooked in the discussion. Thus, in order to estimate the impact of such parameter in the energy consumption and thermal comfort of residential and non-residential buildings, a building model has been simulated by means of Transfer Functions Methods and the Finite Difference Methods. A traditional double brick façade has been considered and the SHC of bricks has been varied from 800 to 1800 kJ/kg K. The thermal behavior of the building has been assessed at several locations in accordance with the Spanish building code. In addition, building orientation has also been shifted from north to south. Although passive strategies have not been considered, the results show significant energy savings (i.e. up to 20%) and a reduction of thermal discomfort (i.e. up to 20%), depending on the type of building and its location

Engineering and harnessing giant atoms in high-dimensional baths: a cold atoms' implementation

Emitters coupled simultaneously to distant positions of a photonic bath, the so-called giant atoms, represent a new paradigm in quantum optics. When coupled to one-dimensional baths, as recently implemented with transmission lines or SAW waveguides, they lead to striking effects such as chiral emission or decoherence-free atomic interactions. Here, we show how to create giant atoms in dynamical state-dependent optical lattices, which offers the possibility of coupling them to structured baths in arbitrary dimensions. This opens up new avenues to a variety of phenomena and opportunities for quantum simulation. In particular, we show how to engineer unconventional radiation patterns, like multi-directional chiral emission, as well as collective interactions that can be used to simulate non-equilibrium many-body dynamics with no analogue in other setups. Besides, the recipes we provide to harness giant atoms in high dimensions can be exported to other platforms where such non-local couplings can be engineered.Comment: 9 pages, 5 figures. Title changed to accommodate to the new focus of the main text. Several typos correcte

Emitters of NN-photon bundles

We propose a scheme based on the coherent excitation of a two-level system in a cavity to generate an ultrabright CW and focused source of quantum light that comes in groups (bundles) of $N$ photons, for an integer $N$ tunable with the frequency of the exciting laser. We define a new quantity, the \emph{purity} of $N$-photon emission, to describe the percentage of photons emitted in bundles, thus bypassing the limitations of Glauber correlation functions. We focus on the case $1\le N\le3$ and show that close to 100% of two-photon emission and 90% of three-photon emission is within reach of state of the art cavity QED samples. The statistics of the bundles emission shows that various regimes---from $N$-photon lasing to $N$-photon guns---can be realized. This is evidenced through generalized correlation functions that extend the standard definitions to the multi-photon level.Comment: Introduce the n-th order N-photon correlation functions. Reorganized to emphasize the N-photon emitter, now extended to the antibunching regime, rather than only coherent emission as previsoul

N-acilaminofenotiazinas y 5,6-dihidro-1,4,5-dibenzo[b,f]tiadiazepinas: fármacos neuroprotectores de posible aplicación en el tratamiento del alzheimer y de otras enfermedades neurodegenerativa

Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Orgánica. Fecha de lectura: 06-03-200

Construyendo dominios de encuentro para problematizar acerca de las prácticas pedagógicas de profesores secundarios de Ciencias: Incorporando el modelo de Investigación-Acción como plan de formación continua

Frente a la actual crisis de la educación científica, la capacidad docente de transformar sus prácticas para mejorar el logro de aprendizajes parece ser fundamental. Los programas de formación docente continua tradicionales, generalmente prescriptivos y descontextualizados del aula, han tenido bajo impacto en los procesos de transformación de las prácticas docentes. El presente trabajo describe la primera fase de un programa de formación continua consistente en la construcción de dominios de encuentro entre el saber académico generado en la Universidad y el saber profesional de 16 profesores secundarios de Ciencias a través de un proceso de investigación-acción conjunta, basado en el trabajo colaborativo, la reflexión y la retroalimentación. Los resultados dan cuenta de la complejidad de generar significados comunes, los que una vez logrados, permiten fortalecer el razonamiento científico, la autoeficacia y conformación de una comunidad de aprendizaje que posibilita una actitud indagatoria hacia sus prácticas en Ciencias. / Considering the current scientific education crisis, teachers' capacity to transform their practice in order to improve learning achievement seems fundamental. The traditional programs of continuous professional development, generally prescriptive and uncontextualized from the classroom, have had a low impact on processes of teachers' practice transformation. This work describes the first stage of continuous development program, consisting on building encounter domains between the academic knowledge of Universities, and professional knowledge of 16 secondary science teachers, through a joint action-research process, based on collaborative work, reflection and feedback. The results show the complexity of building shared sense which, once achieved, allows strong scientific reasoning, self-efficacy and the construction of a learning community facilitating an inquiry-driven attitude towards their science teaching practice

A encruzilhada das relativas não estândar entre o espanhol (E) e português brasileiro(PB) e seus efeitos sobre a aprendizagem de ELE por brasileiros

IX Congresso Brasileiro de Hispanistas realizado nos dias 22 a 25 agosto 2016Ainda que a formação das construções relativas seja semelhante no espanhol (E) e no português brasileiro (PB), o uso das relativas restritivas não estândar parece ser diferente. No E, por um lado, é bastante comum a relativa com pronome resumptivo (Brucart, 1999), (Es una chica que ya te he dicho que ayer hablamos con ella), sobretudo quando o antecedente é indefinido e está distante da cláusula relativa; por outro, não são comuns ou aceitas as construções oblíquas com um complementizador (Rivero, 1982, apud Liceras, 1986, p. 47) e a preposição elidida (?Este es el libro que he hablado muchas veces). Já em PB a formação preferida é a com complementizador e sem preposição –segundo Tarallo (1983) uma cortadora (A moça que eu falei ontem está aqui)– frente à construção com resumptivo (A moça que eu falei com ela ontem está aqui), atualmente estigmatizada.Com o objetivo de investigar o grau de aceitabilidade das relativas especificativas no E por falantes do PB e determinar em que medida se produz transferência da L1, aplicamos um teste de Juízo de Aceitabilidade a 30 falantes de ELE cuja língua materna é o PB e a um grupo de controle de 30 hispanofalantes. Os resultados mostraram que o grau de aceitação das construções cortadoras é mais alto que o grau de aceitabilidade das relativas com resumptivo. Os hispano- falantes vão em direção oposta: as construções de resumptivo apresentaram um grau mais alto de aceitabilidade que as cortadoras, o que permite concluir que os falantes do PB transferem suas preferências ao E, tal como podíamos predizer a partir das propostas dos linguistasUNILA­-UNIOEST