The parameter space of Cubic Galileon models for cosmic acceleration

We use recent measurements of the expansion history of the universe to place constraints on the parameter space of cubic Galileon models, in particular we concentrate on those models which contain the simplest Galileon term plus a linear potential. This gives strong constraints on the Lagrangian of these models. Most dynamical terms in the Galileon Lagrangian are constraint to be small and the acceleration is effectively provided by a constant term in the scalar potential, thus reducing, effectively, to a LCDM model for current acceleration. The effective equation of state is indistinguishable from that of a cosmological constant w = -1 and the data constraint it to have no temporal variations of more than at the few % level. The energy density of the Galileon can contribute only to about 10% of the acceleration energy density, being the other 90% a cosmological constant term. This demonstrates how useful direct measurements of the expansion history of the universe are at constraining the dynamical nature of dark energy.Comment: References added. Minor changes. Published version. 11 pages, 4 figure

Constraints on deviations from Λ{\Lambda}CDM within Horndeski gravity

Recent anomalies found in cosmological datasets such as the low multipoles of the Cosmic Microwave Background or the low redshift amplitude and growth of clustering measured by e.g., abundance of galaxy clusters and redshift space distortions in galaxy surveys, have motivated explorations of models beyond standard $\Lambda$CDM. Of particular interest are models where general relativity (GR) is modified on large cosmological scales. Here we consider deviations from $\Lambda$CDM+GR within the context of Horndeski gravity, which is the most general theory of gravity with second derivatives in the equations of motion. We adopt a parametrization in which the four additional Horndeski functions of time $\alpha_i(t)$ are proportional to the cosmological density of dark energy $\Omega_{DE}(t)$. Constraints on this extended parameter space using a suite of state-of-the art cosmological observations are presented for the first time. Although the theory is able to accommodate the low multipoles of the Cosmic Microwave Background and the low amplitude of fluctuations from redshift space distortions, we find no significant tension with $\Lambda$CDM+GR when performing a global fit to recent cosmological data and thus there is no evidence against $\Lambda$CDM+GR from an analysis of the value of the Bayesian evidence ratio of the modified gravity models with respect to $\Lambda$CDM, despite introducing extra parameters. The posterior distribution of these extra parameters that we derive return strong constraints on any possible deviations from $\Lambda$CDM+GR in the context of Horndeski gravity. We illustrate how our results can be applied to a more general frameworks of modified gravity models.Comment: 22 pages; 4 figures; 9 tables. The constraints have been revised to match the precision required according to the recently released hi_class pape

One-Dimensional Gas Dynamics in Nitrous Oxide Rocket Systems

Liquid and hybrid rocket systems that utilize high-pressure liquid nitrous oxide (N2O) are susceptible to accidental decompression. These very rare events have catastrophic potential and have led to loss of human life in the past. Traditional thinking considers those events as driven by catalytic chemical decomposition reactions; the objective of this work is to examine such events in the light of BLEVE (Boiling Liquid Expanding Vapor Explosion). The static picture of BLEVE will be described here as a metastable phase transition between liquid and vapor phases, using Clausius II thermodynamics (statics) to describe the retrograde behavior of the fluid. The dynamics of a hypothetical BLEVE process inside nitrous rocket-propellant tanks will also be examined using 1-D gas dynamics, and specifically by considering three ’canonical’ flows and their combinations: Area variation, Fanno friction flow, and Rayleigh heat addition. This thesis will provide an outline of Clausius II and how it was applied to various flows through the use of a 1D model coded in Python [5]. The results obtained from this coded model will be plotted and explained in order to either validate or give further work ideas to the theory initially provided

Conductive Polymer Composites Synthesized from Diacetylene-Functionalized Linseed Oil and MWCNT: Gamma Irradiation and Organic Vapor Sensing

Beca de estancia de Posdoctorado del Dr. Alejandro Ramírez JiménezEpoxidized linseed oil (ELO) was synthesized and functionalized with propargylamine (PA) or 3-ethynylaniline (EA) and the products were crosslinked to obtain the diacetylene-functionalized epoxidized linseed oil polymers which were used as matrices in the preparation of the composites with multiwalled carbon nanotubes (MWCNTs). Electrical resistance at percentages between 4 and 20 wt/wt% of filler was measured and the percolation threshold was calculated, obtaining 1.2 and 1.7% for the composites with EA and PA respectively. Low critical concentration evidenced a good dispersion of the MWCNTs without necessity of any modification. The final products were used in the sensing of acetone, chloroform and ethanol. The electrical resistance changes were measured at different concentrations and the sensibility was calculated. In order to improve stability toward the vapors, composites were irradiated with gamma rays and new sensing was done and compared. The results showed differences in sensibility, selectivity and reproducibility.CONACy

Promoción del destino turístico de la festividad del Sr. de Qoyllority de Ocongate, provincia de Quispicanchi, Cusco-2019

En la presente investigación se tiene como objetivo describir el destino turístico de la festividad del Sr de Qoyllority en el distrito de Ocongate, provincia de Quispicanchi, Cusco 2019. La Metodología de la investigación fue de nivel básico, de tipo descriptivo simple, de corte transversal; la población muestra estuvo conformada por 62 familias de la zona de Ocongate, todos los datos recogidos mediante el cuestionario empleados, fueron procesados mediante el programa estadístico SPSS. v. 23 y Excel, organizados en base a categorías y dimensiones mediante tablas y gráficos estadísticos. Entre los resultados se tiene que el destino turístico de la festividad del Sr de Qoyllority en el distrito de Ocongate-Quispicanchi-Cusco, perciben el 59.7% de los pobladores que es regular el cuidado de los atractivos naturales, religiosos y culturales, lo mismo sucede con la accesibilidad turística y la calidad de atención de los recursos humanos que se tiene en la zona de Ocongate y el 12.9% menciona que es bajo. De los resultados se asume que los servicios y atractivos culturales, religiosos propios del destino se mejoren, generando cambios en la geografía, artesanía adecuada, venta de productos pecuarios y agroecológicos y ofrecer circuitos turísticos y dinamización del folklore, pero con adecuada capacitación.This research aims to describe the tourist promotion of the festivity of Lord of Qoyllority in the district of Ocongate, Province of Quispicanchi, Cusco 2019. The research methodology was basic, simple descriptive, cross-sectional; The sample population consisted of 62 families from the Ocongate area, including the workers of the Municipality, all the data collected through the questionnaire used, were processed through the SPSS statistical program. v. 23 and Excel, organized based on categories and dimensions using statistical tables and graphs. Among the results is that the tourist destination of the festivity of Mr. de Qoyllority in the district of Ocongate, province of Quispicanchi, Cusco 2019, is not adequate, this is established from the perception of the residents surveyed, 69.4% of them mention that is to regulate the activities that are held in the tourist destination of the holiday and 30.6% consider that the activities carried out in said holiday are high. The results assume the need to disseminate the various activities that are possible to develop within this holiday

Diseño e implementación de un sistema de medición para obtener el patrón de radiación de antenas utilizando un analizador de redes vectoriales.

El presenten trabajo de titulación tuvo como objetivo diseñar e implementar un sistema de medición para obtener el patrón de radiación de antenas utilizando un analizador de redes vectoriales (VNA). Para ello se estudió las características principales de cada uno de los equipos y el rango de frecuencias de operación del VNA que va desde los 300 KHz a 20 GHz. Se utilizo una estructura de posicionamiento para controlar el ángulo de azimut y el eje vertical, el movimiento sobre el ángulo de azimut fue controlado mediante un Arduino Uno, mientras que el movimiento vertical que posiciona la antena de prueba fue controlado por los módulos NI 9512 conectados al sistema de adquisición de datos cRIO 9035, la estructura de posicionamiento utilizada se ubicó dentro de la cámara anecoica permitiendo eliminar todas las interferencias electromagnéticas existentes en el ambiente. La antena de prueba se conectó al puerto dos del analizador de redes vectoriales mientras que la antena patrón se conectó al primer puerto del VNA, la separación de estas antenas fue mayor a la zona de campo lejano permitiendo extraer la información del coeficiente de transmisión S21. La aplicación diseñada en el software LabView permitió realizar acciones sincronizadas y automatizar la calibración del VNA, extrayendo los datos a medida que variaba el ángulo de azimut de la antena de prueba, generando un vector con los parámetros S21 para posteriormente poder graficar el patrón de radiación de la antena en coordenadas polares y rectangulares que se muestra al usuario mediante una interfaz gráfica.The objective of this degree work was to design and implement a measurement system to obtain the radiation pattern of antennas using a vector network analyzer (VNA). For this, the main characteristics of each of the equipment and the range of operating frequencies of the VNA that goes from 300 KHz to 20 GHz were studied. A positioning structure was used to control the azimuth angle and the vertical axis, the movement about the azimuth angle was controlled by an Arduino one, while the vertical movement that positions the test antenna was controlled by the connected NI 9512 modules which were connected to the cRIO 9035 data acquisition system, the positioning structure used was located inside the anechoic chamber, allowing the elimination of all electromagnetic interference existing in the environment. The test antenna was connected to port two of the vector network analyzer while the pattern antenna was connected to the first port of the VNA. The separation of these antennas was greater than the far field zone, allowing the extraction of the information on the S21 transmission coefficient. The application designed in the LabView software allowed synchronized actions and automate the VNA calibration, extracting the data as the azimuth angle of the test antenna varied, generating a vector with the S21 parameters to later be able to graph the radiation pattern. of the antenna in polar and rectangular coordinates that is shown to the user through a graphical interface

Protein flexibility is key to cisplatin crosslinking in calmodulin

Chemical crosslinking in combination with Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) has significant potential for studying protein structures and proteinprotein interactions. Previously, cisplatin has been shown to be a crosslinker and crosslinks multiple methionine (Met) residues in apo-calmodulin (apo-CaM). However, the inter-residue distances obtained from nuclear magnetic resonance structures are inconsistent with the measured distance constraints by crosslinking. Met residues lie too far apart to be crosslinked by cisplatin. Here, by combining FTICR MS with a novel computational flexibility analysis, the flexible nature of the CaM structure is found to be key to cisplatin crosslinking in CaM. It is found that the side chains of Met residues can be brought together by flexible motions in both apo-CaM and calcium-bound CaM (Ca4-CaM). The possibility of cisplatin crosslinking Ca4-CaM is then confirmed by MS data. Therefore, flexibility analysis as a fast and low-cost computational method can be a useful tool for predicting crosslinking pairs in protein crosslinking analysis and facilitating MS data analysis. Finally, flexibility analysis also indicates that the crosslinking of platinum to pairs of Met residues will effectively close the nonpolar groove and thus will likely interfere with the binding of CaM to its protein targets, as was proved by comparing assays for cisplatin-modified/unmodified CaM binding to melittin. Collectively, these results suggest that cisplatin crosslinking of apo-CaM or Ca4-CaM can inhibit the ability of CaM to recognize its target proteins, which may have important implications for understanding the mechanism of tumor resistance to platinum anticancer drugs