6,923 research outputs found

    La Capilla Real de Palacio en la crisis del Antiguo Régimen: 1808-1820

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    La entronización en España de José Bonaparte, su caída tras la derrota del ejército francés y el regreso de Fernando VII son sucesos que afectarán a la Capilla Real de Palacio del mismo modo que repercutieron en el resto de las instituciones seglares y eclesiásticas de la Monarquía. En este trabajo se pretende, pues, analizar el impacto de esos acontecimientos en la estructura y el funcionamiento de la Capilla Real, así como en su personal, el cual, obligado por las circunstancias, tuvo forzosamente que tomar partido a su pesar, con las consecuencias que de tal decisión se derivaban para su futuro profesional.The enthronement of Jose I, his fall after the defeat of french army and the return of Fernando VII, are events that affected to the Royal Chapel of Palace in same way they had effects on the rest of institutions, lay and ecclesiastical, of the Monarchy. This articule tries, therefore, to analize the repercutions of those facts on structure and functions of the Royal Chapel as on its personel, who oblied by circunstancies were forced to take party facing the effects that such a decision would have on their later careers

    Coupled electric and magnetic dipole formulation for planar arrays of dipolar particles: metasurfaces with various electric and/or magnetic meta-atoms per unit cell

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    The optical properties of infinite planar array of scattering particles, metasurfaces and metagratings, are attracting special attention lately for their rich phenomenology, including both plasmonic and high-refractive-index dielectric meta-atoms with a variety of electric and magnetic resonant responses. Herein we derive a coupled electric and magnetic dipole (CEMD) analytical formulation to describe the reflection and transmission of such periodic arrays, including specular and diffractive orders, valid in the spectral regimes where only dipolar multipoles are needed. Electric and/or magnetic dipoles with all three orientations arising in turn from a single or various meta-atoms per unit cell are considered. The 2D lattice Green function is rewritten in terms of a 1D (chain) version that fully converges and can be easily calculated. Modes emerging as poles of such lattice Green function can be extracted. This formulation can be applied to investigate a wealth of plasmonic, all-dielectric, and hybrid metasurfaces/metagratings of interest throughout the electromagnetic spectrum.Comment: 8 pages, 4 figure

    Ergonomics in Laparoscopic Surgery

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    Despite the many advantages for patients, laparoscopic surgery entails certain ergonomic inconveniences for surgeons, which may result in decreasing the surgeons’ performance and musculoskeletal disorders. In this chapter, the current status of ergonomics in laparoscopy, laparoendoscopic single‐site surgery (LESS), and robot‐assisted surgery will be reviewed. Ergonomic guidelines for laparoscopic surgical practice and methods for ergonomic assessment in surgery will be described. Results will be based on the scientific literature and our experience. Results showed that the surgeon\u27s posture during laparoscopic surgery is mainly affected by the static body postures, the height of the operating table, the design of the surgical instruments, the position of the main screen, and the use of foot pedals. Ergonomics during the laparoscopic surgical practice is related to the level of experience. Better ergonomic conditions entail an improvement in task performance. Laparoscopic instruments with axial handle lead to a more ergonomic posture for the wrist compared to a ring handle. LESS is physically more demanding than conventional and hybrid approaches, requiring greater level of muscular activity in the back and arm muscles, but better wrist position compared with traditional laparoscopy. Physical and cognitive ergonomics with robotic assistance were significantly less challenging when compared to conventional laparoscopic surgery

    Handheld Devices for Laparoscopic Surgery

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    Despite the well-known benefits of minimally invasive surgery (MIS) to the patients, this surgical technique implies some technical challenges for surgeons. These technical limitations are increased with the introduction of laparoendoscopic single-site (LESS) surgery. In order to overcome some of these technical difficulties, new handheld devices have been developed, providing improved functionalities along with precision-driven and articulating instrument tips. In this chapter, we will review the current status of handheld devices for laparoscopy and LESS surgery. Devices that provide additional and innovative functionalities in comparison with conventional surgical instruments will be considered. Results will be based on studies published in the scientific literature and our experience. These surgical devices will be organized into two main groups, mechanical devices and robotic-driven devices. In general, these instruments intend to simulate the dexterity of movements of a human wrist. Mechanical devices are cheaper and easier to develop, so most of the available handheld instruments fall into this category. The majority of the robotic-driven devices are needle holders with an articulating tip, controlled by an interface implemented on the instrument handle. In general, these handheld devices claim to offer an enhancement of dexterity, precision, and ergonomics
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