Analysis of consensus protocols under time delays in directed graphs

Consensus protocols, used in multiagent systems to achieve agreements, are affected by inherent issues into the communication networks. An interesting research problem is the effect of time delays in the process, which could prevent the system to obtain the desired agreement equilibrium. In this work we propose to use the Lambert W function to analyze the input time delays in a system of interacting agents, assuming directed graphs to represent a network with simple-integrator dynamics in each agent. Then, a closed-form for the marginally-stable delay is obtained and tested with simulations in a study case. © 2017 IEEE

Utilidad de una prueba cualitativa para la detección de fibronectina fetal en secreción cervicovaginal como predictor de parto prematuro

ResumenLa fibronectina fetal es una glucoproteína de la matriz extracelular que se localiza en la interfase materno-fetal de las membranas amnióticas, entre la decidua y el corion. Los niveles séricos de fibronectina fetal≥50ng/ml a partir de las 22 semanas de gestación más se han asociado con un riesgo de partos prematuros espontáneos.El parto prematuro es el nacimiento que se presenta antes de las 37 semanas de gestación, es multicausal, contribuye con un 70% de la mortalidad perinatal y su prevalencia oscila entre el 7-10%. Las infecciones de transmisión sexual y del tracto urinario son factores de riesgo importantes. En mujeres nulíparas es difícil determinar el riesgo, en multíparas el traumatismo cervical es la principal causa de pérdidas en el segundo trimestre de gestación y de partos prematuros, otros factores son edad materna, bacteriuria asintomática y la vaginosis bacteriana.Existen diversos marcadores para la predicción del parto prematuro, a fin de superar las debilidades del examen obstétrico y permitir así un diagnóstico y tratamiento oportuno. Entre estos marcadores se encuentra la determinación de fibronectina fetal en secreciones vaginales, por lo que el objetivo de este estudio fue evaluar la utilidad de la fibronectina fetal como un predictor de parto prematuro en embarazadas, así como establecer la sensibilidad, especificidad y los valores predictivos de la prueba, con el propósito de valorar su uso en embarazadas con factores de riesgo en las unidades de primer nivel de atención.AbstractThe foetal fibronectin is an extracellular matrix glycoprotein that is located in the maternal-foetal interface of the amniotic membranes between the decidua and chorion. The serum levels of foetal fibronectin≥50ng/ml at the end of 22 weeks have been associated with an increased risk of spontaneous preterm birth. The foetal fibronectin is one of the best predictors of preterm birth that may help to identify women at risk of preterm delivery.Preterm delivery is the birth that occurs before 37 weeks of gestation. It has multiple causes and is associated with the 70% of perinatal mortality cases. Its prevalence ranges from 7-10%. In nulliparous women the risk is difficult to determine, in multiparous the cervical trauma is the main cause of losses in the second trimester and preterm births, other factors are maternal age, asymptomatic bacteriuria and bacterial vaginosis.There are several markers for the prediction of preterm delivery, to overcome the weaknesses of the obstetric examination and thus allow diagnosis and treatment. One of these markers is the determination of foetal fibronectin in vaginal secretions, so the aim of this study was to evaluate the usefulness of foetal fibronectin as a predictor of preterm delivery in pregnant women, calculate the sensitivity, specificity, and the predictive values of the test, in order to assess its use in pregnant women with risk factors in units of primary care

HPV-associated lung cancers: An international pooled analysis

Human papillomavirus (HPV) is the etiologic risk factor for cervical cancer. Some studies have suggested an association with a subset of lung tumors, but the etiologic link has not been firmly established. We performed an international pooled analysis of crosssectional studies (27 datasets, n = 3249 patients) to evaluate HPV DNA prevalence in lung cancer and to investigate viral presence according to clinical and demographic characteristics. HPV16/18 were the most commonly detected, but with substantial variation in viral prevalence between geographic regions. The highest prevalence of HPV16/18 was observed in South and Central America, followed by Asia, North America and Europe (adjusted prevalence rates = 22, 5, 4 and 3%, respectively). Higher HPV16 prevalence was noted in each geographic region compared with HPV18, except in North America. HPV16/18-positive lung cancer was less likely observed among White race (adjusted odds ratio [OR] = 0.33, 95% confidence interval [CI] = 0.12-0.90), whereas no associations were observed with gender, smoking history, age, histology or stage. Comparisons between tumor and normal lung tissue show that HPV was more likely to be present in lung cancer rather than normal lung tissues (OR = 3.86, 95% CI = 2.87-5.19). Among a subset of patients with HPV16-positive tumors, integration was primarily among female patients (93%, 13/14), while the physical status in male cases (N = 14) was inconsistent. Our findings confirm that HPV DNA is present in a small fraction of lung tumors, with large geographic variations. Further comprehensive analysis is needed to assess whether this association reflects a causal relationship. © The Author 2014. Published by Oxford University Press. All rights reserved