Metafluid dynamics and Hamilton-Jacobi formalism

Metafluid dynamics was investigated within Hamilton-Jacobi formalism and the existence of the hidden gauge symmetry was analyzed. The obtained results are in agreement with those of Faddeev-Jackiw approach.Comment: 7 page

Modelo para el tratamiento de la deuda técnica orientado a la evolución de los componentes para que las aplicaciones sean sostenibles a largo plazo

La Deuda Técnica es un fenómeno habitual del proceso de construcción de software, la cual es reconocida como un conjunto de malas prácticas y decisiones incorrectas en la fase de construcción de software, aceptada generalmente como efecto colateral en proyectos de software donde puede existir presiones de cronograma y con entregas continuas de valor a corto plazo. Ciertos aspectos de este fenómeno son conocidos de forma general, lo que sigue sin conocerse en profundidad, es cómo la deuda técnica se manifiesta y afecta específicamente los procesos de software, y cómo las técnicas de desarrollo de software empleadas acomodan o mitigan la presencia de esta deuda (Holvitie et al., 2018). La deuda técnica ha ganado visibilidad en los últimos años debido al interés en los proyectos de software que usan marcos de desarrollo ágil, los cuales detallan la responsabilidad que tienen los equipos de desarrollo en producir código de calidad, y que en su afán de entregar software funcionando en el menor tiempo posible, renuncian a actividades relacionadas con la producción de código de calidad, como son, el uso de buenas prácticas de codificación, definiciones de diseños y arquitecturas incompletas, poca cobertura de pruebas y documentación, entre otros, que a largo plazo acumulan una gran cantidad de deuda técnica que se vuelve perjudicial para el éxito de los proyectos. Parte de este estudio es comprender los antecedentes, dimensiones, atributos y consecuencias de la deuda técnica, para así poder proponer un modelo de referencia para el tratamiento de la deuda técnica, y cómo puede éste ser adaptado como parte de un proceso de madurez similar a los existentes en desarrollo de software general. El entendimiento de las causas para lograr que las aplicaciones puedan ser sostenibles a largo plazo, será el principal enfoque para la selección de las principales técnicas para el tratamiento de la deuda técnica definidas en la literatura, las tecnologías y herramientas que serán útiles para registrar y hacer las mediciones de deuda técnica, especificar qué actividades y ejemplos claros de cómo deberían ser implementadas según el modelo por parte de los equipos de desarrollo, contribuyendo a reducir y gestionar la deuda técnica en las aplicaciones. El modelo propuesto debe proporcionar un enfoque útil para comprender y gestionar la deuda técnica con fines prácticos, que involucre futuras líneas de investigación.Technical Debt is a common phenomenon of the software construction process, the quality is recognized as a set of bad practices and incorrect decisions in the software construction phase, normally accepted as a side effect in software projects where there may be schedule difficulties and with continuous deliveries of short-term value. Certain aspects of this phenomenon are generally known, what remains unknown in depth, is how technical debt manifests and specifically affects software processes, and how the software development techniques used accommodate or mitigate the presence of this debt (Holvitie et al., 2018).Technical debt has gained visibility in recent years due to interest in software projects that use agile development frameworks, which detail the responsibility that development teams have in producing quality code, and that in their eagerness to deliver software functioning in the shortest possible time, they give up activities related to the production of quality code, such as the use of good coding practices, definitions of incomplete designs and architectures, little evidence and documentation coverage, among others, that over term accumulate a large amount of technical debt that becomes detrimental to the success of the projects. Part of this study is to understand the background, dimensions, attributes and consequences of technical debt, in order to propose a reference model for the treatment of technical debt, and how it can be adapted as part of a maturity process similar to those existing in general software development. Understanding the causes to ensure that applications can be sustainable in the long term will be the main approach for the selection of the main techniques for the treatment of technical debt defined in the literature, the technologies and tools that will be useful for recording and make the measurements of technical debt, specify what activities and clear examples of how they should be implemented according to the model by the development teams, contributing to reduce and manage the technical debt in the applications. The proposed model should provide a useful approach to understand and manage technical debt for practical purposes, which involves future lines of research.Magíster en Ingeniería de SoftwareMaestrí

Smooth hybrid inflation in supergravity with a running spectral index and early star formation

It is shown that in a smooth hybrid inflation model in supergravity adiabatic fluctuations with a running spectral index with \ns >1 on a large scale and \ns <1 on a smaller scale can be naturally generated, as favored by the first-year data of WMAP. It is due to the balance between the nonrenormalizable term in the superpotential and the supergravity effect. However, since smooth hybrid inflation does not last long enough to reproduce the central value of observation, we invoke new inflation after the first inflation. Its initial condition is set dynamically during smooth hybrid inflation and the spectrum of fluctuations generated in this regime can have an appropriate shape to realize early star formation as found by WMAP. Hence two new features of WMAP observations are theoretically explained in a unified manner.Comment: 12 pages, 1 figure, to appear in Phys. Rev.

Planck 2015 results. XXVII. The Second Planck Catalogue of Sunyaev-Zeldovich Sources

We present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ) sources detected from the 29 month full-mission data. The catalogue (PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced and the deepest all-sky catalogue of galaxy clusters. It contains 1653 detections, of which 1203 are confirmed clusters with identified counterparts in external data-sets, and is the first SZ-selected cluster survey containing > $10^3$ confirmed clusters. We present a detailed analysis of the survey selection function in terms of its completeness and statistical reliability, placing a lower limit of 83% on the purity. Using simulations, we find that the Y5R500 estimates are robust to pressure-profile variation and beam systematics, but accurate conversion to Y500 requires. the use of prior information on the cluster extent. We describe the multi-wavelength search for counterparts in ancillary data, which makes use of radio, microwave, infra-red, optical and X-ray data-sets, and which places emphasis on the robustness of the counterpart match. We discuss the physical properties of the new sample and identify a population of low-redshift X-ray under- luminous clusters revealed by SZ selection. These objects appear in optical and SZ surveys with consistent properties for their mass, but are almost absent from ROSAT X-ray selected samples

Planck intermediate results. VIII. Filaments between interacting clusters

About half of the baryons of the Universe are expected to be in the form of filaments of hot and low density intergalactic medium. Most of these baryons remain undetected even by the most advanced X-ray observatories which are limited in sensitivity to the diffuse low density medium. The Planck satellite has provided hundreds of detections of the hot gas in clusters of galaxies via the thermal Sunyaev-Zel'dovich (tSZ) effect and is an ideal instrument for studying extended low density media through the tSZ effect. In this paper we use the Planck data to search for signatures of a fraction of these missing baryons between pairs of galaxy clusters. Cluster pairs are good candidates for searching for the hotter and denser phase of the intergalactic medium (which is more easily observed through the SZ effect). Using an X-ray catalogue of clusters and the Planck data, we select physical pairs of clusters as candidates. Using the Planck data we construct a local map of the tSZ effect centered on each pair of galaxy clusters. ROSAT data is used to construct X-ray maps of these pairs. After having modelled and subtracted the tSZ effect and X-ray emission for each cluster in the pair we study the residuals on both the SZ and X-ray maps. For the merging cluster pair A399-A401 we observe a significant tSZ effect signal in the intercluster region beyond the virial radii of the clusters. A joint X-ray SZ analysis allows us to constrain the temperature and density of this intercluster medium. We obtain a temperature of kT = 7.1 +- 0.9, keV (consistent with previous estimates) and a baryon density of (3.7 +- 0.2)x10^-4, cm^-3. The Planck satellite mission has provided the first SZ detection of the hot and diffuse intercluster gas.Comment: Accepted by A&

Opioid suppression of conditioned anticipatory brain responses to breathlessness

Opioid painkillers are a promising treatment for chronic breathlessness, but are associated with potentially fatal side effects. In the treatment of breathlessness, their mechanisms of action are unclear. A better understanding might help to identify safer alternatives. Learned associations between previously neutral stimuli (e.g. stairs) and repeated breathlessness induce an anticipatory threat response that may worsen breathlessness, contributing to the downward spiral of decline seen in clinical populations. As opioids are known to influence associative learning, we hypothesized that they may interfere with the brain processes underlying a conditioned anticipatory response to breathlessness in relevant brain areas, including the amygdala and the hippocampus. Healthy volunteers viewed visual cues (neutral stimuli) immediately before induction of experimental breathlessness with inspiratory resistive loading. Thus, an association was formed between the cue and breathlessness. Subsequently, this paradigm was repeated in two identical neuroimaging sessions with intravenous infusions of either low-dose remifentanil (0.7ng/ml target controlled infusion) or saline (randomised). During saline infusion, breathlessness anticipation activated the right anterior insula and the adjacent operculum. Breathlessness was associated with activity in a network including the insula, operculum, dorsolateral prefrontal cortex, anterior cingulate cortex and the primary sensory and motor cortices. Remifentanil reduced breathlessness unpleasantness but not breathlessness intensity. Remifentanil depressed anticipatory activity in the amygdala and the hippocampus that correlated with reductions in breathlessness unpleasantness. During breathlessness, remifentanil decreased activity in the anterior insula, anterior cingulate cortex and sensory motor cortices. Remifentanil-induced reduction in breathlessness unpleasantness was associated with increased activity in the rostral anterior cingulate cortex and nucleus accumbens, components of the endogenous opioid system known to decrease the perception of aversive stimuli. These findings suggest that in addition to effects on brainstem respiratory control, opioids palliate breathlessness through an interplay of altered associative learning mechanisms. These mechanisms provide potential targets for novel ways to develop and assess treatments for chronic breathlessness