Improved Measurement of ttZ Couplings at the LHC

We consider QCD tt~Z production at the LHC with Z->\bar\nu\nu and all-hadronic tt~ decays, i.e. pp -> p_T(miss)bb~+4 jets, as a tool to measure ttZ couplings. This channel has a significantly larger cross section than those where the Z boson decays leptonically. However, tt~, bb~+4 jet, tt~j and tt~jj production give rise to potentially large backgrounds. We show that these processes can be suppressed to an acceptable level with suitable cuts, and find that adding the p_T(miss)bb~+4 jet channel to the final states used in previous ttZ couplings analyses will improve the sensitivity by 10-60%. We also discuss how the measurement of the ttZ couplings may constrain Little Higgs models.Comment: revtex4, 16 pages, 4 figures, 1 tabl

Classical versus Quantum Structure of the Scattering Probability Matrix. Chaotic wave-guides

The purely classical counterpart of the Scattering Probability Matrix (SPM) $\mid S_{n,m}\mid^2$ of the quantum scattering matrix $S$ is defined for 2D quantum waveguides for an arbitrary number of propagating modes $M$. We compare the quantum and classical structures of $\mid S_{n,m}\mid^2$ for a waveguide with generic Hamiltonian chaos. It is shown that even for a moderate number of channels, knowledge of the classical structure of the SPM allows us to predict the global structure of the quantum one and, hence, understand important quantum transport properties of waveguides in terms of purely classical dynamics. It is also shown that the SPM, being an intensity measure, can give additional dynamical information to that obtained by the Poincar\`{e} maps.Comment: 9 pages, 9 figure

Chaotic Waveguide-Based Resonators for Microlasers

We propose the construction of highly directional emission microlasers using two-dimensional high-index semiconductor waveguides as {\it open} resonators. The prototype waveguide is formed by two collinear leads connected to a cavity of certain shape. The proposed lasing mechanism requires that the shape of the cavity yield mixed chaotic ray dynamics so as to have the appropiate (phase space) resonance islands. These islands allow, via Heisenberg's uncertainty principle, the appearance of quasi bound states (QBS) which, in turn, propitiate the lasing mechanism. The energy values of the QBS are found through the solution of the Helmholtz equation. We use classical ray dynamics to predict the direction and intensity of the lasing produced by such open resonators for typical values of the index of refraction.Comment: 5 pages, 5 figure

On the classical-quantum correspondence for the scattering dwell time

Using results from the theory of dynamical systems, we derive a general expression for the classical average scattering dwell time, tau_av. Remarkably, tau_av depends only on a ratio of phase space volumes. We further show that, for a wide class of systems, the average classical dwell time is not in correspondence with the energy average of the quantum Wigner time delay.Comment: 5 pages, 1 figur

Introducing medical parasitology at the University of Makeni, Sierra Leone

The file attached to this record is the author's final peer reviewed version.Capacity building in Sierra Leone (West Africa) is critical to prevent potential future outbreaks similar to the 2013-16 Ebola outbreak that had devastating effects for the country and its poorly developed healthcare system. De Montfort University (DMU) in the United Kingdom (UK), in collaboration with parasitologists from the Spanish Universities of San Pablo CEU and Miguel Hernández de Elche, is leading a project to build the teaching and research capabilities of medical parasitology at the University of Makeni (UniMak, Sierra Leone). This project has two objectives: a) to introduce and enhance the teaching of medical parasitology, both theoretical and practical; and b) to implement and develop parasitology research related to important emerging human parasites such as Cryptosporidium spp. due to their public health significance. Two UniMak academics, hired to help initiate and implement the research part of the project, shared their culturally sensitive public health expertise to broker parasitology research in communities and perform a comprehensive environmental monitoring study for the detection of different emerging human parasites. The presence of targeted parasites are being studied microscopically using different staining techniques, which in turn have allowed UniMak’s academics to learn these techniques to develop new practicals in parasitology. To train UniMak’s academics and develop both parts of our project, a DMU researcher visited UniMak for two weeks in April 2019 and provided a voluntary short training course in basic parasitology, which is currently not taught in any of their programmes, and was attended by 31 students. These sessions covered basic introduction to medical parasitology and life-cycle, pathogenesis, detection, treatment and prevention of: a) coccidian parasites (Cryptosporidium, Cyclospora and Cystoisospora); b) Giardia intestinalis, Entamoeba and free-living amoebas; c) malaria and d) microsporidia. A theoretical session on common staining techniques was also provided. To facilitate the teaching and learning of these parasites, the novel resource DMU e-Parasitology was used, a package developed by the above participating universities and biomedical scientists from the UK National Health Service (NHS): http://parasitology.dmu.ac.uk/ index.htm. Following the two weeks of training, UniMak’s academics performed different curriculum modifications to the undergraduate programme ‘Public Health: Medical Laboratory Sciences’, which includes the introduction of new practicals in parasitology and changes to enhance the content of medical parasitology that will be subjected to examination. Thus, a new voluntary practical on Kinyoun stain for the detection of coccidian parasites was introduced in the final year module of ‘Medical Bacteriology and Parasitology’; eighteen students in pairs processed faecal samples from pigs provided by the Department of Agriculture and Food Security from a nearby farm. Academics at UniMak used the Kinyoun staining unit (available at http://parasitology.dmu.ac.uk/learn/lab/Kinyoun/story_html5.html; [1]) to deliver this practical. Although our project is at a preliminary stage, it has been shown to be effective in promoting the introduction and establishment of medical parasitology at UniMak and could be viewed as a case-study for other universities in low-income countries to promote the United Nations (UN) Sustainable Development Goals (SDGs) and improve public health understanding of infectious diseases

Las redes de Petri en la paralelización eficiente de aplicaciones: caso de uso

En este trabajo se presenta el método basado en modelos de Redes de Petri para el análisis y paralelización eficiente de aplicaciones programadas con un paradigma secuencial. Primeramente, se realiza el modelo de la aplicación secuencial. Enseguida, se analizan las partes paralelizables, y se presenta un modelo en Red de Petri de la aplicación paralelizada. A partir del modelo en Red de Petri, se realiza la verificación de la construcción del modelo y se analiza de manera informal la relación de los P-Invariantes con la paralelización del modelo. Finalmente, se realiza una comparación del tiempo de cómputo entre el paradigma secuencial y el paralelo. Se utiliza la multiplicación de matrices como caso de estudio y se reportan los resultados experimentales.Universidad de Guadalajar

Construcción de observadores de secuencias para sistemas de eventos discretos

Este trabajo presenta el diseño e implementación de algoritmos para la construcción de observadores de secuencias para sistemas de eventos discretos. El modelo del sistema se captura como una Red de Petri, mientras que la implementación del es quema del observador se realiza en Simulink. Los algoritmos permiten verificar la propiedad de observabilidad, a la vez que construyen la matriz de detección de secuencias sobre la que se basa el funcionamiento del observador.Universidad de GuadalajaraITESO, A.C

Bubble and Dew Point Calculations in Multicomponent and Multireactive Mixtures

Bubble and dew point calculations are useful in chemical engineering and play an important role in the study of separation equipments for non-reactive and reactive mixtures. To the best of the authors’s knowledge, few methods have been proposed for these calculations in systems with several chemical reactions. The objective of this paper is to introduce new conditions for performing bubble and dew point calculations in reactive mixtures. We have developed these conditions based on the application of transformed variables of Ung and Doherty (1995). Using these transformed variables, the solution space is restricted to compositions that are already at chemical equilibrium and by consequence the problem dimension is also reduced. The reliability and efficiency of three equation-solving methods are tested and compared using our equilibrium conditions: a) a simultaneous equation-solving approach using Newton method (SESN), b) an equation-decoupling approach using successive substitution method (EDSS) and c) an optimization approach using the stochastic optimization method Simulated Annealing(OSA). Our results indicated that even for simple reactive systems, bubble and dew point calculations are challenging for classical equation-solving methods and require robust strategies. We conclude that OSA and EDSS methods are reliable to locate bubble and dew points in reactive systems. EDSS is more efficient than OSA; however, OSA does not need initial guesses and is more suitable for difficult problems

Multi-wavelength Observations of Dusty Star Formation at Low and High Redshift

This paper examines what can be learned about high-redshift star formation from the small fraction of high-redshift galaxies' luminosities that is emitted at accessible wavelengths. We review and quantify empirical correlations between bolometric luminosities produced by star formation and the UV, mid-IR, sub-mm, and radio luminosities of galaxies in the local universe. These correlations suggest that observations of high-redshift galaxies at any of these wavelengths should constrain their star-formation rates to within 0.2--0.3 dex. We assemble the limited evidence that high-redshift galaxies obey these locally calibrated correlations. The characteristic luminosities and dust obscurations of galaxies at z ~ 0, z ~ 1, and z ~ 3 are reviewed. After discussing the relationship between the high-redshift populations selected in surveys at different wavelengths, we calculate the contribution to the 850um background from each. The available data show that a correlation between star-formation rate and dust obscuration L_dust/L_UV exists at low and high redshift. This correlation plays a central role in the major conclusion of this paper: most star formation at high redshift occurred in galaxies with 1 < L_dust/L_UV < 100 similar to those that host the majority of star formation in the local universe and to those that are detected in UV-selected surveys. (abridged)Comment: Scheduled for publication in ApJ v544 Dec 2000. Significant changes to section 4. Characteristic UV and dust luminosities of star-forming galaxies at redshifts z~0, z~1, and z~3 presented. Existence of extremely obscured galaxies more clearly acknowledged. Original conclusions reinforced by the observed correlation between bolometric luminosity and dust obscuration at 0<z<