Multi-Objective and Financial Portfolio Optimization of Carrier-Sense Multiple Access Protocols with Cooperative Diversity

8th International Workshop on Multiple Access Communications (MACOM2015), Helsinki, Finland.This paper presents a trade-off design and optimization of a class of wireless carrier-sense multiple access protocols where collision-free transmissions are assisted by the potential cooperative retransmissions of inactive terminals with a correct copy of the original transmission. Terminals are enabled with a decode-and-forward relaying protocol. The analysis is focused on asymmetrical settings, where terminals experience different channel and queuing statistics. This work is based on multi-objective and financial portfolio optimization tools. Each packet transmission is thus regarded not only as a network resource, but also as a financial asset with different values of return and risk (or variance of the return). The objective of this financial optimization is to find the transmission policy that simultaneously maximizes return and minimizes risk in the network. The work is focused on the characterization of the boundaries (envelope) of different types of trade-off performance regions: the conventional throughput region, sum-throughput vs. fairness, sum-throughput vs. power, and return vs. risk regions. Fairness is evaluated by means of the Gini-index, which is a metric commonly used in economics to measure income inequality. Transmit power is directly linked to the global transmission rate. The protocol is shown to outperform non-cooperative solutions under different network conditions that are here discussed

Impedance and resistance of carbon ink during cure

The resistivity of cured conductive ink films are dependent on a wide range of process parameters. An early indication of the resistivity that is likely to result following curing can enable these parameters to be optimised and, therefore, improve product quality. This paper aims to report on the use of alternating current (AC) impedance measurement techniques on curing printed ink films as a means of assessing the resistivity likely to be attained following the curing process. Design/methodology/approach - Impedance measurements (100 Hz-10 MHz) were performed on curing conductive carbon ink films printed on polyethylene terephthalate substrates during convective heat curing. A jig was designed to incorporate the test structure in an convection oven such that the effect of cure on the structure impedance could be investigated. Findings - The initial impedance was found to decrease with an increase in the measurement frequency. As the ink films were cured, the impedance magnitude across the 100 Hz-10 MHz range converged with the direct current (DC) resistance value. For a given ink, the ratio of initial AC impedance at 10 MHz to final cured resistance was found to be consistent, thus giving a method where final conductivity can be estimated before cure. Originality/value - Data from printed ink resistance measurements are required to ensure the optimal conductivity of printed devices. However, after the printed structures are fabricated and cured, it is too late to optimise process parameters, leading to significant wastage. AC impedance measurement can give an indication of the final cured resistivity whilst the structure is freshly printed and still in its curing phase, enabling the printing process parameters to be adjusted to improve the resistivity of subsequently printed devices. Measuring AC impedance of printed ink structures in a production environment can, therefore, improve output

Estudio preliminar sobre el desperdicio de alimentos en la cafetería de la Facultad de Ciencias Biológicas

En esta investigación se estimó el desperdicio de alimento, generado por una población (1000 personas) constituida por estudiantes y profesores de la Facultad de Ciencias Biológicas (FCB) de la Universidad Autónoma de Nuevo León (UANL). Este desperdicio corresponde al residuo de comida rápida y residuos de platos generados de la comida buffet, estimado según lo señalado por la población (durante su estancia en la universidad), a través de un cuestionario diseñado y aplicado en línea utilizando la plataforma SIASE (Sistema Integral para la administración de Servicios educativos de la UANL). El estudio tuvo como objetivo conocer las características del consumidor (según edad, poder adquisitivo e índice de masa corporal), sus hábitos de consumo y el residuo que genera, según su tipo y cantidad. Los resultados muestran que el 70% de los estudiantes tiene un peso corporal normal (IMC=25), la mayoría (96%) de ellos se encuentra en el rango de edad entre 18 a 28 años y más de la mitad (55%) destina entre 20 y 50 pesos para comprar alimentos. Estos datos, sugieren que la población estudiantil tiene un presupuesto limitado para alimentarse en la universidad, lo cual es congruente con su baja frecuencia de consumo por semana (2 o 3 veces). Lo anterior refiere que el poder adquisitivo influye en la preferencia que tienen los estudiantes por alimentos económicos como: galletas, pan, chilaquiles, hot dog, tacos, tortas, papas fritas con queso y bebidas embotelladas (refresco y jugos). Respecto a la población de profesores el 61% posee un IMC>25, gasta entre $50 a$100 en la compra de alimentos y genera residuos de platos tales como: carne, pollo o pescado (10%); arroz o pastas (10%); además, ensalada o verduras (20%), pan o tortillas (15%) y bebidas gaseosas (>20% de su volumen). Con base en los resultados del cuestionario, adicionalmente se diseñaron menús económicos ($18.00-$30.00 pesos) que contienen subproductos de alimentos producidos durante su preparación, con el fin de promover hábitos de alimentación más saludables en los estudiantes e implementar una estrategia de reducción del desperdicio, resultados que no evaluamos en esta investigación. Este estudio preliminar de estimación de desperdicios alimentarios esboza algunos de los factores requeridos para determinar en futuras investigaciones, la magnitud de los desperdicios alimentarios y cuantificar sus efectos en el ámbito económico, social y ambiental. El conocimiento de esta magnitud podría utilizarse como referencia para proponer la estrategia de reducción de los residuos de alimentos

Clinical features of patients with homozygous complement C4A or C4B deficiency

Introduction Homozygous deficiencies of complement C4A or C4B are detected in 1-10% of populations. In genome-wide association studies C4 deficiencies are missed because the genetic variation of C4 is complex. There are no studies where the clinical presentation of these patients is analyzed. This study was aimed to characterize the clinical features of patients with homozygous C4A or C4B deficiency. Material and methods Thirty-two patients with no functional C4A, 87 patients with no C4B and 120 with normal amount of C4 genes were included. C4A and C4B numbers were assessed with genomic quantitative real-time PCR. Medical history was studied retrospectively from patients' files. Results Novel associations between homozygous C4A deficiency and lymphoma, coeliac disease and sarcoidosis were detected. These conditions were present in 12.5%, (4/32 in patients vs. 0.8%, 1/120, in controls, OR = 17.00, 95%Cl = 1.83-158.04, p = 0.007), 12.5% (4/32 in patients vs. 0%, 0/120 in controls, OR = 1.14, 95%Cl = 1.00-1.30, p = 0.002) and 12.5%, respectively (4/32 in patients vs. 2.5%, 3/120 in controls, OR = 5.571, 95%Cl = 1.79-2.32, p = 0.036). In addition, C4A and C4B deficiencies were both associated with adverse drug reactions leading to drug discontinuation (34.4%, 11/32 in C4A-deficient patients vs. 14.2%, 17/120 in controls, OR = 3.174, 95%Cl = 1.30-7.74, p = 0.009 and 28.7%, 25/87 in C4B-deficient patients, OR = 2.44, 95%Cl = 1.22-4.88, p = 0.010). Conclusion This reported cohort of homozygous deficiencies of C4A or C4B suggests that C4 deficiencies may have various unrecorded disease associations. C4 gene should be considered as a candidate gene in studying these selected disease associations.Peer reviewe

Synthesis of Nitrogenated Heterocycles by Asymmetric Transfer Hydrogenation of N-(tert-Butylsulfinyl)haloimines

Highly optically enriched, protected, nitrogenated heterocycles with different ring sizes have been synthesized by a very efficient methodology consisting of the asymmetric transfer hydrogenation of N-(tert-butylsulfinyl)haloimines followed by treatment with a base to promote an intramolecular nucleophilic substitution process. N-Protected aziridines, pyrrolidines, piperidines, and azepanes bearing aromatic, heteroaromatic, and aliphatic substituents have been obtained in very high yields and diastereomeric ratios up to >99:1. The free heterocycles can be easily obtained by a simple and mild desulfinylation procedure. Both enantiomers of the free heterocycles can be prepared with the same good results by changing the absolute configuration of the sulfur atom of the sulfinyl group.This work was generously supported by the Spanish Ministerio de Ciencia e Innovación (MICINN; grant no. CONSOLIDER INGENIO 2010, CSD2007-00006, CTQ2007-65218 and CTQ2011-24151) and the Generalitat Valenciana (PROMETEO/2009/039 and FEDER). O.P. thanks the Spanish Ministerio de Educación for a predoctoral fellowship (grant no. AP-2008-00989)

Separación de Gases y Vapores utilizando Materiales Porosos Moleculares

En el Proyecto de Tesis de Maestría se ha previsto evaluar la capacidad de separación de mezclas de gases y vapores de tres familias de materiales moleculares porosos, en particular, imidazolatos y de derivados de metales de transición, enrejados metal-orgánicos y polímeros de coordinación a partir de datos de Cromatografía de Gases Inversa (IGC). A partir de las curvas de IGC se evaluarán los calores de adsorción para las diferentes componentes en una mezcla data para luego estimar el poder separativo de los materiales para las diferentes mezclas consideradas [1]. A partir de los datos de IGC complementados con isotermas de adsorción registradas bajo condiciones de equilibrio se obtendrá información acerca de la naturaleza de las interacciones responsables de la separación o no de una mezcla dada