292 research outputs found
“Fernando Napoleón”: Un laboratorio global para la revolución del Río de la Plata (1808-1815)
El proceso que desencadenó las renuncias de los Borbones a la corona de España para cederla
a la Casa de Bonaparte y el rechazo de gran parte de la población peninsular a aceptar al nuevo
rey, José I, es por cierto muy conocido. Ante la inexistencia de canales supletorios que pudieran
prever la ausencia del rey en las leyes fundamentales de la monarquía, las primeras reacciones
frente a la acefalía apelaron al principio de retroversión de la soberanía sobre los pueblos de
los reinos peninsulares a partir de una serie de preceptos escolásticos embebidos de teorías del
derecho natural. Las juntas conformadas para ejercer la autoridad provisional, en calidad de
depósito y tutela de la soberanía del rey cautivo en la localidad francesa de Valençay, echaron
mano a moldes políticos medievales y se organizaron de manera colegiada. En esa operación, violenta y cargada de improvisaciones, yacía un principio fundamental: el consentimiento de
los pueblos como piedra angular de la legitimidad política. El poder del rey dejaba de ser un
hecho dado y providencial, para volverse activo a través de la voluntad de los cuerpos
soberanos2
. Una transición que fue gradual y a la vez traumática. En ese punto de inflexión, los
personajes de Pérez Galdós exhiben, precisamente, la perplejidad nacida de la crisis. Las tres
imágenes que se presentan en Bailén respecto de la autoridad del rey –la defensa acérrima, la
duda taciturna y el boceto más seglar asumido por Santorcaz– sintetizan un repertorio de
respuestas que están en la base de los problemas centrales que se exploran en las siguientes
páginas.
El objeto de esta tesis se recorta, pues, en el estudio de las representaciones que se fueron
construyendo en el seno de las elites políticas y letradas rioplatenses en torno a la figura del
rey ausente desde la acefalía de la Corona hasta los meses posteriores a la batalla de Waterloo
en 18153
. Como ocurrió en la propia península y en el resto de las jurisdicciones
hispanoamericanas, dichas representaciones se diseñaron y reformularon en un diálogo
constante y contrastante con el otro personaje central del proceso: Napoleón Bonaparte. Ambas
figuras condensaron los dilemas del momento y a través de ellas es posible rastrear las
variaciones que se fueron configurando entre soberanía y autoridad, por un lado, y entre guerra
y política, por el otro
Educación étnica y nacionalismo vasco en la Argentina : el caso de Euskal Echea (1899-1919)
La cuestión del nacionalismo vasco, estudiada ampliamente por la historiografía
en su extensión internacional, plantea la necesidad de un abordaje que considere el análisis
de diferentes procesos que se entrecruzaron hacia fines del siglo XIX y principios del XX:
naciones y nacionalismos en el contexto europeo, español y euskaldun; flujos
internacionales; coyuntura económica; problemáticas sociales, entre otros. El presente
trabajo tiene como objetivo examinar una asociación en particular fundada por un grupo de
inmigrantes vascos en la Argentina entre 1899 y 1904: la Sociedad de Beneficencia, asilo y
colegio Euskal Echea. Una de las tareas más complejas emprendidas a lo largo de estas
páginas será incorporar el examen de la coyuntura internacional y hacerla partícipe de la
evolución microscópica que acapara su centro de atención. Su eje y principal desafío, sin
embargo, será demostrar que pese a sus peculiaridades, Euskal Echea es hija de su tiempo,
y su ímpetu coincide con el del aluvión asociativo que caracterizó al siglo XIX. Si bien sus
estímulos fundacionales podrían llevar a muchos a pensar que se erigió como una
representación del nacionalismo vasco en Argentina, nuestra propuesta consistirá, no
obstante, en matizar esta conjetura a partir de la comparación con otras asociaciones que
contemplaron en su seno este tipo de debates que de una manera u otra influyeron en su
configuración posterior. Desde aquí observamos que Euskal Echea no se presenta como
una institución que levante las banderas del nacionalismo independentista vasco delineado
en la década de 1890 por Sabino Arana, aunque no pudo estar exenta de un debate que poco
a poco arribaba a la Argentina y salpicaba a la comunidad euskalduna toda
Evaluation of Tooth Space Pressure and Incomplete Filling in External Gear Pumps by Means of Three-Dimensional CFD Simulations
The paper presents the computational fluid dynamics simulation of an external gear pump for fluid power applications. The aim of the study is to test the capability of the model to evaluate the pressure in a tooth space for the entire shaft revolution and the minimum inlet pressure for the complete filling. The model takes into account the internal fluid leakages and two different configurations of the thrust plates have been considered. The simulations in different operating conditions have been validated with proper high dynamics transducers measuring the internal pressure in a tooth space for the entire shaft revolution. Steady-state simulations have been also performed in order to detect the fall of the flow rate due to the incomplete filling of the tooth spaces when the inlet pressure is reduced. It has been demonstrated that, despite the need of a compromise for overcoming the limitation of considering fixed positions of the gears’ axes and of the thrust plates, significant results can be obtained, making the CFD approach very suitable for such analyses
CFD Analyses of Textured Surfaces for Tribological Improvements in Hydraulic Pumps
In any hydraulic machine there are lubricated couplings that could become critical beyond certain operating conditions. This paper presents the simulation results concerning textured surfaces with the aim of improving the performance of lubricated couplings in relative motion. The texturing design requires much care to obtain good improvements, and it is essential to analyze both the geometric features of the dimples and the characteristics of the coupled surfaces, like the sliding velocity and gap height. For this purpose, several CFD simulations have been performed to study the behavior of the fluid bounded in the coupling, considering dimples with different shapes, size, and spatial distribution. The simulations consider the onset of gaseous cavitation to evaluate the influence of this phenomenon on the pressure distribution generated by the textured surface. The analyses have pointed out that it is critical to correctly predict the behavior of the textured surface in the presence of local cavitation, in fact, when cavitation occurs, the characteristic time of the transient in which the phase of the fluid change is very rapid and it is comparable to the time taken by the fluid to move from one dimple to the next
I reinterventi nell’iperparatiroidismo
reinterventi in chirurgia paratiroidea rappresentano una sfida impegnativa per il chirurgo che deve valutare attentamente i dati operatori e istologici del primo intervento, usare una diagnostica accurata preoperatoria con ecografia e scintigrafia con sestamibi e avere ben presente l’anatomia e l’embriologia delle ghiandole paratiroidee. Elementi fondamentali per ottenere un successo chirurgico sono l’uso del dosaggio intraoperatorio del paratormone e una grande esperienza del chirurgo. Seguendo tali principi si arriva a ottenere una remissione del quadro iperparatiroideo nell’85-90% per l’HPT I e nel 70% per l’HPT II e III.
Gli Autori presentano la loro casistica di 75 reinterventi dopo HPT I e di 85 reinterventi dopo HPT II e III, su una casistica totale di 2072 interventi di paratiroidectomia eseguiti fra gennaio 1975 e ottobre 2009
Hydraulic Hybrid Excavator: Layout Definition, Experimental Activity, Mathematical Model Validation and Fuel Consumption Evaluation
Energy saving and fuel consumption reduction techniques are among the principal interests for both academic institutions and industries, in particular, system optimization and hybridization. This paper presents a new hydraulic hybrid system layout for mobile machinery implemented on a middle size excavator. The hybridization procedure took advantage of a dynamic programming (DP) algorithm, which was also utilized for the hybrid components dimensioning and control strategy definition. A dedicated experimental activity on test bench was performed on the main components of the energy recovery system (ERS). The JCMAS working cycle was considered as the reference test for a fuel consumption comparison between the standard and the hybrid excavator. A fuel saving up to 8% on the JCMAS cycle, and up to 11% during the digging cycle, has been allowed by the proposed hybrid system
Angiomatoid Fibrous Histiocytoma: Case Presentation with Review of Literature
Angiomatoid fibrous histiocytoma is a rare neoplasm with an intermediate malignant potential, that mostly occurs in the subcutis and features varying proportions of epithelioid, ovoid and spindle cells in a nodular and syncytial growth pattern, with hemorrhagic pseudovascular spaces. Here, we report the clinical case of a 68-year-old man who presented with AFH on the right arm; the disease relapsed a few years after surgical excision. We also conduct a brief review of the literature, focusing on the biological and genetic characteristics and the differential diagnosis from other more or less similar entities
Pleomorphic Hyalinizing Angiectatic Tumor (PHAT): Review of the Literature with Case Presentation
Pleomorphic hyalinizing angiectatic tumor (PHAT) is a very rare entity of soft tissue considered a “neoplasm of uncertain behaviour of connective or other soft tissue” by the World Health Organization (2020). It develops in subcutaneous tissue of the lower extremities, more frequently in the region of the ankle and foot, and rarely as a deep-seated soft tissue mass in locations such as the perineum, buttock, arms, head and neck, and viscera. Although inconsistent cytogenetic data have been reported on PHAT so far, there are potential morphological and genetic overlaps with hemosiderotic fibrolipomatous tumor (HFLT) and myxoinflammatory fibroblastic sarcoma (MIFS). Here we report a case of PHAT at the level of the upper third of the right thigh in a 48-year-old patient and we also focus on the differential diagnoses of these entities and conduct a literature review of reported cases
“Animal-Type Melanoma/Pigmented Epithelioid Melanocytoma”: History and Features of a Controversial Entity
Animal-type melanoma (ATM) was first described in the literature by Levene in 1979 in relation to a patient with a characteristic clinical presentation, and only later, rare and anecdotal case series have tried to shed light on an entity that has undergone several nosographic classification changes, and which, since 2018, is classified under the term "pigmented epithelioid melanocytoma". Here, we conduct a brief review of the current literature on ATM and present a new clinical case with histopathological, immunophenotypic, and molecular investigations
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