Sistemas de colas en tiempo discreto con entradas y servicios en bloque: estudio teórico y simulaciones comparativas

Los sistemas de colas se vienen estudiando desde inicios del siglo XX. Suele formarse una cola ante una instalación que proporciona determinado servicio. La teoría de colas pretende estudiar las fluctuaciones que se producen en estas situaciones: el número de clientes, el tiempo que debe esperar cada uno antes de ser atendido, la duración del tiempo de servicio … En este trabajo se plantean algunos modelos de colas con un solo servidor en los que los clientes llegan y son atendidos en grupos, no necesariamente del mismo tamaño. El estudio se hace mediante simulación y mediante análisis probabilístico y se comparan los resultados obtenidos por ambos procedimientos. Se mide la eficiencia de cada modelo en términos de acumulación de clientes y tiempos de espera de acuerdo con los parámetros que los gobiernan. También se comparan las eficiencias de los modelos planteados

Effect of parameters on Geoa/Geob/1 Queues: theoretical analysis and simulation results

This paper analyzes a discrete-time Geoa/Geob/1 queuing system with batch arrivals of fixed size a , and batch services of fixed size b. Both arrivals and services occur randomly following a geometric distribution. The steady-state queue length distribution is obtained as the solution of a system of difference equations. Necessary and sufficient conditions are given for the system to be stationary. Besides, the uniqueness of the root of the characteristic polynomial in the interval (0, 1) is proven which is the only root needed for the computation of the theoretical solution with the proposed procedure. The theoretical results are compared with the ones observed in some simulations of the queuing system under different sets of parameters. The agreement of the results encourages the use of simulation for more complex systems. Finally, we explore the effect of parameters on the mean length of the queue as well as on the mean waiting time

El desarrollo del pensamiento crítico en niños/as de cuatro y cinco años a través de la lectura de álbumes ilustrados de Anthony Browne

En este trabajo se indaga, a través de una metodología cualitativa de carácter etnográfico, acerca de la posible capacidad de influencia en el desarrollo de pensamiento crítico de los niños de educación infantil las obras literarias de Anthony Browne. Para ello se utiliza el enfoque “Dime” Chambers, (2007). Concretamente, el estudio revela algunas variables relacionadas con las obras de este autor de libros infantiles sobre dicha influencia. Se ha recurrido al diseño de estudio de caso, utilizando la observación participante como método y la grabación de datos como técnica. Las producciones de los sujetos, notas de campo e información de informantes han servido para triangular los datos obtenidos. El proceso de análisis ha permitido identificar ideas y hechos en posible relación con el problema de investigación. Este estudio se aproxima en unas conclusiones interpretativas de la realidad investigada, extrayendo sentidos con cierto significado basado en la globalidad de aspectos que han intervenido en el proceso: datos recogidos, metodología, obras, ambiente, recepción y la propia reflexividad de la persona que investiga

Direct-acting antiviral therapy improves kidney survival in hepatitis C virus-associated cryoglobulinaemia: the RENALCRYOGLOBULINEMIC study

Background: Direct-acting antiviral agents (DAAs) have shown high rates of sustained virological response in chronic hepatitis C virus (HCV) infection. However, the influence of DAAs on the course of kidney involvement in HCV-associated mixed cryoglobulinaemia (HCV-MC) has been little studied. The aim of this study was to analyse the effects of antiviral treatment on kidney prognosis and evolution in patients diagnosed with HCV-MC. Methods: The RENALCRYOGLOBULINEMIC study is an observational multicentre cohort study of 139 patients with HCV-MC from 14 Spanish centres. Clinical and laboratory parameters were measured before and after antiviral treatment. Primary endpoints were kidney survival and mortality after HCV-MC diagnosis. Secondary endpoints were clinical, immunological and virological responses after antiviral treatment. Results: Patients were divided into three groups based on the treatment received: treatment with DAAs (n = 100) treatment with interferon (IFN) and ribavirin (RBV) (n = 24) and no treatment (n = 15). Patients were followed up for a median duration of 138 months (interquartile range 70-251. DAA treatment reduced overall mortality {hazard ratio [HR] 0.12 [95% confidence interval (CI) 0.04-0.40]; P < 0.001} and improved kidney survival [HR 0.10 ( 95% CI 0.04-0.33); P < 0.001]. Conclusions: Results from the RENALCRYOGLOBULINEMIC study indicated that DAA treatment in patients with HCV-MC improves kidney survival and reduces mortality

Criteria for admitting elderly patients with acute coronary syndrome to critical care units from Spanish hospital emergency departments: a LONGEVO-SCA cohort study

Objetivo: la información sobre los condicionantes de ingreso en unidades de críticos (UC) de pacientes ancianos con síndrome coronario agudo (SCA) es escasa. El objetivo de este estudio fue describir los factores asociados al ingreso en UC en una serie de ancianos no seleccionados con SCA en España. Métodos: el registro LONGEVO-SCA incluyó prospectivamente pacientes 80 años con SCA sin elevación del segmento ST (SCASEST), realizándose una valoración geriátrica intrahospitalaria y analizándose la evolución clínica a los 6 meses. Se analizaron los condicionantes de ingreso en UC mediante regresión logística binaria. Resultados: de un total de 508 pacientes (edad media 84,3 años), 150 (29,5%) fueron ingresados en UC. Los pacientes ingresados en UC presentaban menor edad, mayor proporción de insuficiencia cardíaca aguda, troponina positiva y peor función ventricular izquierda, así como puntuaciones superiores en las escalas de riesgo GRACE y ACTION-ICU. Estos pacientes presentaban, asimismo, una mejor situación funcional y una menor prevalencia de fragilidad, y fueron sometidos a coronariografía con mayor frecuencia (p < 0,001). No se apreciaron diferencias en mortalidad hospitalaria ni evolución a los 6 meses entre ambos grupos. Los predictores independientes de ingreso en UC fueron la ausencia de insuficiencia cardíaca previa, troponina positiva al ingreso, disfunción ventricular izquierda, valores elevados en la escala GRACE y en el índice de Charlson, y ausencia de fragilidad. Conclusiones: alrededor de un tercio de los ancianos con SCASEST son ingresados en UC. Los pacientes ingresados en UC presentan mayor perfil de riesgo al ingreso y menor prevalencia de síndromes geriátricos

Immigrant IBD Patients in Spain Are Younger, Have More Extraintestinal Manifestations and Use More Biologics Than Native Patients

BackgroundPrevious studies comparing immigrant ethnic groups and native patients with IBD have yielded clinical and phenotypic differences. To date, no study has focused on the immigrant IBD population in Spain. MethodsProspective, observational, multicenter study comparing cohorts of IBD patients from ENEIDA-registry who were born outside Spain with a cohort of native patients. ResultsWe included 13,524 patients (1,864 immigrant and 11,660 native). The immigrants were younger (45 +/- 12 vs. 54 +/- 16 years, p < 0.001), had been diagnosed younger (31 +/- 12 vs. 36 +/- 15 years, p < 0.001), and had a shorter disease duration (14 +/- 7 vs. 18 +/- 8 years, p < 0.001) than native patients. Family history of IBD (9 vs. 14%, p < 0.001) and smoking (30 vs. 40%, p < 0.001) were more frequent among native patients. The most prevalent ethnic groups among immigrants were Caucasian (41.5%), followed by Latin American (30.8%), Arab (18.3%), and Asian (6.7%). Extraintestinal manifestations, mainly musculoskeletal affections, were more frequent in immigrants (19 vs. 11%, p < 0.001). Use of biologics, mainly anti-TNF, was greater in immigrants (36 vs. 29%, p < 0.001). The risk of having extraintestinal manifestations [OR: 2.23 (1.92-2.58, p < 0.001)] and using biologics [OR: 1.13 (1.0-1.26, p = 0.042)] was independently associated with immigrant status in the multivariate analyses. ConclusionsCompared with native-born patients, first-generation-immigrant IBD patients in Spain were younger at disease onset and showed an increased risk of having extraintestinal manifestations and using biologics. Our study suggests a featured phenotype of immigrant IBD patients in Spain, and constitutes a new landmark in the epidemiological characterization of immigrant IBD populations in Southern Europe

Correction : Chaparro et al. Incidence, Clinical Characteristics and Management of Inflammatory Bowel Disease in Spain: Large-Scale Epidemiological Study. J. Clin. Med. 2021, 10, 2885

The authors wish to make the following corrections to this paper [...]

Incidence, Clinical Characteristics and Management of Inflammatory Bowel Disease in Spain : Large-Scale Epidemiological Study

(1) Aims: To assess the incidence of inflammatory bowel disease (IBD) in Spain, to describe the main epidemiological and clinical characteristics at diagnosis and the evolution of the disease, and to explore the use of drug treatments. (2) Methods: Prospective, population-based nationwide registry. Adult patients diagnosed with IBD-Crohn's disease (CD), ulcerative colitis (UC) or IBD unclassified (IBD-U)-during 2017 in Spain were included and were followed-up for 1 year. (3) Results: We identified 3611 incident cases of IBD diagnosed during 2017 in 108 hospitals covering over 22 million inhabitants. The overall incidence (cases/100,000 person-years) was 16 for IBD, 7.5 for CD, 8 for UC, and 0.5 for IBD-U; 53% of patients were male and median age was 43 years (interquartile range = 31-56 years). During a median 12-month follow-up, 34% of patients were treated with systemic steroids, 25% with immunomodulators, 15% with biologics and 5.6% underwent surgery. The percentage of patients under these treatments was significantly higher in CD than UC and IBD-U. Use of systemic steroids and biologics was significantly higher in hospitals with high resources. In total, 28% of patients were hospitalized (35% CD and 22% UC patients, p < 0.01). (4) Conclusion: The incidence of IBD in Spain is rather high and similar to that reported in Northern Europe. IBD patients require substantial therapeutic resources, which are greater in CD and in hospitals with high resources, and much higher than previously reported. One third of patients are hospitalized in the first year after diagnosis and a relevant proportion undergo surgery

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Don Quijote busca a Dulcinea

Cuento con pictogramas sobre Don Quijote y Dulcinea realizado por alumnos de educación infantil que versiona la historia de amor de la novela de Cervantes conmemorando la celebración del 400 aniversario de su primera edición.MurciaConsejería de Educación y Cultura. Biblioteca Regional; Avda. Juan Carlos I, 17; 30008 Murcia; +34968366599; +34968366600; [email protected]