Modelización numérica de un motor de combustión interna monocilíndrico encendido por chispa

El objetivo de este trabajo fue el desarrollo de un código computacional para la resolución de problemas de dinámica de gases en su escurrimiento a través de ductos y toberas y su posterior inserción dentro de un código que simule el ciclo de potencia y el de bombeo en un motor de combustión interna encendido por chispa. Es sabido que los motores de combustión interna son altamente influenciados por el diseño de los múltiples de admisión y escape. Factores como el ruido, la emisión y el rendimiento volumétrico son algunos de los principales temas de actualidad en el área de motores térmicos. Es por esto que en pos de poder modelar un motor y sus partes pensamos que será muy provechoso contar con un desarrollo previo en el flujo en tubos de sección arbitraria, siendo los ductos y las toberas sólo una aplicación particular del código generado. Se utilizó una discretización espacial unidimensional en elementos _nitos con una discretización temporal según un esquema de Lax-Wendro de dos pasos. La física del problema es gobernada por las ecuaciones de Euler, flujo invíscido, con el agregado de términos fuentes para incluir los efectos de la fricción en las paredes del tubo, la variabilidad de la sección de paso del fluido y la transferencia de calor a través de las paredes del ducto. Las primeras secciones introducen acerca de la dinámica de gases en sus aspectos teóricos básicos incluyendo el análisis de discontinuidades tipo ondas de choque. Posteriormente se analizan aspectos numéricos como la formulación empleada, el tratamiento de las condiciones de contorno y las técnicas de resolución numérica del sistema resultante. A continuación se presentan una gran variedad de resultados y su comparación con sus contrapartes analíticas. Finalmente se presentan algunos aspectos computacionales acerca del modelo completo de simulación de un motor de combustión interna encendido por chispa y las curvas características obtenidas para un caso test.Peer Reviewe

Modelización numérica de un motor de combustión interna monocilíndrico encendido por chispa

El objetivo de este trabajo fue el desarrollo de un código computacional para la resolución de problemas de dinámica de gases en su escurrimiento a través de ductos y toberas y su posterior inserción dentro de un código que simule el ciclo de potencia y el de bombeo en un motor de combustión interna encendido por chispa. Es sabido que los motores de combustión interna son altamente influenciados por el diseño de los múltiples de admisión y escape. Factores como el ruido, la emisión y el rendimiento volumétrico son algunos de los principales temas de actualidad en el área de motores térmicos. Es por esto que en pos de poder modelar un motor y sus partes pensamos que será muy provechoso contar con un desarrollo previo en el flujo en tubos de sección arbitraria, siendo los ductos y las toberas sólo una aplicación particular del código generado. Se utilizó una discretización espacial unidimensional en elementos _nitos con una discretización temporal según un esquema de Lax-Wendro de dos pasos. La física del problema es gobernada por las ecuaciones de Euler, flujo invíscido, con el agregado de términos fuentes para incluir los efectos de la fricción en las paredes del tubo, la variabilidad de la sección de paso del fluido y la transferencia de calor a través de las paredes del ducto. Las primeras secciones introducen acerca de la dinámica de gases en sus aspectos teóricos básicos incluyendo el análisis de discontinuidades tipo ondas de choque. Posteriormente se analizan aspectos numéricos como la formulación empleada, el tratamiento de las condiciones de contorno y las técnicas de resolución numérica del sistema resultante. A continuación se presentan una gran variedad de resultados y su comparación con sus contrapartes analíticas. Finalmente se presentan algunos aspectos computacionales acerca del modelo completo de simulación de un motor de combustión interna encendido por chispa y las curvas características obtenidas para un caso test.Peer Reviewe

“Resabios” as subversion. Ethnohistory of the movements of indigenous people, women and workers in the Bolivian «apparent State»

La tesi adotta una prospettiva etnostorica rafforzata da una metodologia etnografica per analizzare lo sviluppo dei processi di politicizzazione nel territorio boliviano dal periodo coloniale ad oggi, collocandoli all’interno di un più ampio sistema di relazioni economiche, politiche e sociali dettate dall’eterogeneo sviluppo del capitalismo globale; la tesi mostra sia il modo specifico in cui, nelle varie contingenze storiche, queste relazioni hanno riorganizzato l’«abigarrada» società boliviana e inciso sui processi di politicizzazione, sia il modo in cui i soggetti hanno contestato e messo in tensione tale riorganizzazione. Per l’analisi si partirà dalla posizione di quei soggetti che sono stati definiti alternativamente come indios, indigeni, campesinos nel territorio boliviano, guardando alle connessioni politiche che questi hanno messo in campo con diversi soggetti – donne, lavoratori, attivisti urbani. Questa posizione offre una «prospettiva epistemologica privilegiata» per indagare il modo in cui i movimenti sociali impattano nell’articolazione tra Stato, società civile e capitale, non perché tali soggetti sono portatori di un’autenticità alternativa al capitalismo, ma perché il modo in cui riattivano quell’insieme di miti, credenze e residui precapitalistici – i «resabios» – che concorrono alla «memoria larga» delle lotte, innestandoli su elementi introdotti dal capitalismo, mostra la loro capacità di sovvertire la posizione subalterna che la riproduzione del capitale nel territorio boliviano ha imposto loro. Si mostreranno anche le tensioni e i conflitti dati dalle diverse posizioni che donne e uomini, giovani e anziani, figure d’autorità e ‘base’ assumono all’interno della loro identificazione come indigeni. La ricerca permette di affermare che l’identità indigena è il prodotto della risposta istituzionale che di volta in volta è stata data per neutralizzare l’emergenza politica di soggetti la cui eterogeneità non ha impedito, ma al contrario ha reso possibile, un’accumulazione di forza tale da mettere in crisi gli assetti politici, economici e istituzionali dello Stato post-coloniale.The dissertation employs an ethnohistorical perspective, combined with an ethnographic methodology, to examine the development of politicisation processes in Bolivia from the colonial period to the present day. These processes are viewed within the wider context of economic, political, and social relations shaped by the uneven development of global capitalism. The dissertation demonstrates how these relations have restructured the «abigarrada» Bolivian society and impacted the politicisation processes in various historical contingencies, as well as how the subjects have contested and challenged this restructuring. The analysis starts from the position of those subjects that have been alternatively defined as indios, indigenous, campesinos within the Bolivian territory, exploring their political connections with different groups, such as women, workers, and urban activists. This approach provides a «privileged epistemological perspective» to understand how social movements influence the relationship between the State, civil society, and capital. The significance of these subjects lies not in their bearing of an alternative authenticity to capitalism, but in their ability to activate a set of myths, beliefs, and pre-capitalist residues – the «resabios» – that contribute to the «memoria larga» of struggles. By grafting these elements onto capitalism, they can subvert the subaltern position imposed on them by the reproduction of capital in Bolivia. The research also reveals the tensions and conflicts arising from different positions held by indigenous people, including women and men, young and old, and authority figures versus the “base”. The research demonstrates that indigenous identity is a product of the institutional response that has been given to neutralise the political emergence of heterogeneous subjects. Their heterogeneity has made possible an accumulation of strength such as to challenge the post-colonial State’s political, economic, and institutional arrangements

Distance as a barrier to cancer diagnosis and treatment: Review of the literature

The burden of travel from a patient’s residence to health care providers is an important issue that can influence access to diagnosis and treatment ofcancer.Although several studies have shown that the travel burden can result in delays in diagnosis and treatment of many common cancers, its role appears underestimated in the treatment of patients in clinical practice. Therefore, we performed a review of the published data on the role of travel burden influencing four items: delay of diagnosis, adequate treatment of cancer, outcome, and quality of life of cancer patients. Forty-seven studies published up to December 2014 were initially identified. Twenty studies were excluded because they did not regard specifically the four items of our review.Twenty-seven studies formed the basis of our study and involved 716,153 patients. The associations between travel burden and (a) cancer stage at diagnosis (12 studies), (b) appropriate treatment (8 studies), (c) outcome (4 studies), and (d) quality of life (1 study) are reported. In addition, in two studies,therelationbetween travel burden and compliance with treatment was examined. The results of our review show that increasing travel requirements are associated with more advanced disease at diagnosis, inappropriatetreatment, aworse prognosis, and a worse quality of life. These results suggest that clinical oncologists should remember the specific travel burden problem for cancer patients, who often need health care services every week or every month for many years

Linfadenitis y absceso subcutáneo por Complejo Mycobacterium avium como manifestación de síndrome inflamatorio de reconstitución inmune luego de un segundo esquema de terapia antirretroviral de gran actividad

El síndrome inflamatorio de reconstitución inmune (SIRI) es una reacción atípica e inesperada relacionada con el tratamiento antirretroviral de gran actividad (TARGA) en pacientes infectados por el virus de la inmunodeficiencia humana (VIH). El SIRI representa una respuesta inflamatoria frente a un patógeno oportunista (generalmente Mycobacterium tuberculosis, Complejo Mycobacterium avium, citomegalovirus y herpes varicela-zóster) en pacientes que responden a la TARGA con una marcada reducción de la carga viral en plasma y evidencia de una recuperación inmunológica expresada por el incremento de los niveles de linfocitos T CD4+. Presentamos el caso de un paciente con síndrome de inmunodeficiencia adquirida que desarrolló un absceso subcutáneo en muslo derecho y una adenitis supraclavicular izquierda como manifestación de SIRI por Complejo Mycobacterium avium luego del inicio de un segundo esquema de TARGA.Immune reconstitution inflammatory syndrome (IRIS) is an atypical and unexpected reaction related to highly active antiretroviral therapy (HAART) in human immunodeficiency virus (HIV) infected patients. IRIS includes an atypical response to an opportunistic pathogen (generally Mycobacterium tuberculosis, Mycobacterium avium complex, cytomegalovirus and herpes varicella-zoster), in patients responding to HAART with a reduction of plasma viral load and evidence of immune restoration based on increase of CD4+ T-cell count. We reported a case of a patient with AIDS which, after a first failure of HAART, developed a subcutaneous abscess and supraclavicular lymphadenitis as an expression of IRIS due to Mycobacterium avium complex after starting a second scheme of HAART

Long-term follow-up free of ventricular fibrillation recurrence after resuscitated cardiac arrest in a myotonic dystrophy type 1 patient

Cardiac involvement in myotonic dystrophy type 1 (DM1) is frequent with increased incidence of conduction disturbances and sudden cardiac death when compared with general population. We describe a 38-year-old man in whom the diagnosis of DM1 was made 8 years after occurrence of cardiac arrest owing to ventricular fibrillation and discuss management of DM1 patients at risk for sudden cardiac death

Prospective assessment of integrating the existing emergency medical system with automated external defibrillators fully operated by volunteers and laypersons for out-of-hospital cardiac arrest: the Brescia Early Defibrillation Study (BEDS)

AIMS: There are few data on the outcomes of cardiac arrest (CA) victims when the defibrillation capability of broad rural and urban territories is fully operated by volunteers and laypersons. METHODS AND RESULTS: In this study, we investigated whether a programme based on diffuse deployment of automated external defibrillators (AEDs) operated by 2186 trained volunteers and laypersons across the County of Brescia, Italy (area: 4826 km(2); population: 1 112 628), would safely and effectively impact the current survival among victims of out-of-hospital CA. Forty-nine AEDs were added to the former emergency medical system that uses manual EDs in the emergency department of 10 county hospitals and in five medically equipped ambulances. The primary endpoint was survival free of neurological impairment at 1-year follow-up. Data were analysed in 692 victims before and in 702 victims after the deployment of the AEDs. Survival increased from 0.9% (95% CI 0.4-1.8%) in the historical cohort to 3.0% (95% CI 1.7-4.3%) (P=0.0015), despite similar intervals from dispatch to arrival at the site of collapse [median (quartile range): 7 (4) min vs. 6 (6) min]. Increase of survival was noted both in the urban [from 1.4% (95% CI 0.4-3.4 %) to 4.0% (95% CI 2.0-6.9 %), P=0.024] and in the rural territory [from 0.5% (95% CI 0.1-1.6%) to 2.5% (95% CI 1.3-4.2%), P=0.013]. The additional costs per quality-adjusted life year saved amounted to euro39 388 (95% CI euro16 731-49 329) during the start-up phase of the study and to euro23 661 (95% CI euro10 327-35 528) at steady state. CONCLUSION: Diffuse implementation of AEDs fully operated by trained volunteers and laypersons within a broad and unselected environment proved safe and was associated with a significantly higher long-term survival of CA victims

Clinical efficacy of ivabradine in patients with inappropriate sinus tachycardia: a prospective, randomized, placebo-controlled, double-blind, crossover evaluation

Objectives The purpose of this study was to investigate the role of ivabradine in the treatment of symptomatic inappropriate sinus tachycardia using a double-blind, placebo-controlled, crossover design. Background Due to its If blocking properties, ivabradine can selectively attenuate the high discharge rate from sinus node cells, causing inappropriate sinus tachycardia. Methods Twenty-one patients were randomized to receive placebo (n = 10) or ivabradine 5 mg twice daily (n = 11) for 6 weeks. After a washout period, patients crossed over for an additional 6 weeks. Each patient underwent symptom evaluation and heart rate assessment at the start and finish of each phase. Results After taking ivabradine, patients reported elimination of >70% of symptoms (relative risk: 0.25; 95% CI: 0.18 to 0.34; p < 0.001), with 47% of them experiencing complete elimination. These effects were associated with a significant reduction of heart rate at rest (from 88 ± 11 beats/min to 76 ± 11 beats/min, p = 0.011), on standing (from 108 ± 12 beats/min to 92 ± 11 beats/min, p < 0.0001), during 24 h (from 88 ± 5 beats/min to 77 ± 9 beats/min, p = 0.001), and during effort (from 176 ± 17 beats/min to 158 ± 16 beats/min, p = 0.001). Ivabradine administration was also associated with a significant increase in exercise performance. No cardiovascular side effects were observed in any patients while taking ivabradine. Conclusions In this cohort, ivabradine significantly improved symptoms associated with inappropriate sinus tachycardia and completely eliminated them in approximately half of the patients. These findings suggest that ivabradine may be an important agent for improving symptoms in patients with inappropriate sinus tachycardia

Imaging diagnosis: ultrasonographic appearance of small bowel metastasis from canine mammary carcinoma

A 10-year-old entire female Beagle dog was evaluated for an acute history of lethargy, anorexia, and diarrhea. Mammary tumors were detected during physical examination. Ultrasonographic scanning revealed the presence of a unique pattern of multiple, well-defined and well-marginated hypoechoic nodules in the muscularis layer of the jejunum. These nodules were not associated with changes in the rest of the normal intestinal layering and were not causing signs of intestinal obstruction. Mammary carcinoma metastases to the intestinal muscularis layer were diagnosed based on histopathological examination