124 research outputs found
Significación preindustrial e industrial de la pesca y sus concomitancias en las faenas de la flota andaluza del Atlántico.
Sin resume
Urbanització dels terrenys de l’antiga fà brica de Can Batlle. Dipòsit de pluvials soterrat i urbanització de la plaça superior a Girona
Maximum population transfer in a periodically driven two-level system
We study the dynamics of a two-level quantum system under the influence of
sinusoidal driving in the intermediate frequency regime. Analyzing the Floquet
quasienergy spectrum, we find combinations of the field parameters for which
population transfer is optimal and takes place through a series of well defined
steps of fixed duration. We also show how the corresponding evolution operator
can be approximated at all times by a very simple analytical expression. We
propose this model as being specially suitable for treating periodic driving at
avoided crossings found in complex multi-level systems, and thus show a
relevant application of our results to designing a control protocol in a
realistic molecular modelComment: 7 pages, 6 figure
Correspondence between classical and quantum resonances
Bifurcations take place in molecular Hamiltonian nonlinear systems as the excitation energy increases, leading to the appearance of different classical resonances. In this paper, we study the quantum manifestations of these classical resonances in the isomerizing system CN-Li Li-CN. By using a correlation diagram of eigenenergies versus Planck constant, we show the existence of different series of avoided crossings, leading to the corresponding series of quantum resonances, which represent the quantum manifestations of the classical resonances. Moreover, the extrapolation of these series to h = 0 unveils the correspondence between the bifurcation energy of classical resonances and the energy of the series of quantum resonances in the semiclassical limit → 0. Additionally, in order to obtain analytical expressions for our results, a semiclassical theory is develope
Unraveling the highly nonlinear dynamics of KCN molecular system using Lagrangian descriptors
In this work, we identify the phase-space structures which are responsible for the chaotic dynamics observed in KCN molecular system using the Lagrangian descriptors. We show that the vibrational dynamics of this molecule is strongly determined by the invariant manifolds associated with a particular stretching periodic orbit previously described (Párraga et al., 2018). Likewise, the representation of these invariant manifolds on a Poincaré surface of section is also studied, concluding that the intricate depiction that is observed has its origin in the complex behavior of the manifolds, which is a consequence of the strong anharmonicities in the potential energy surfaceThis work has been partially supported by the Grants PID2021-122711NB-C21 and CEX2019-000904-S funded by MCIN/AEI/10.13039/501100011033, by the People Programme (Marie Curie Actions) of the European Union’s Horizon 2020 Research and Innovation Program under Grant No. 734557, and by the Comunidad de Madrid, Spain under the Grant APOYO-JOVENES-4L2UB6-53-29443N (GeoCoSiM) financed within the Plurianual Agreement with the Universidad Politécnica de Madrid, Spain in the line to improve the research of young doctor
The Poincare-Birkhoff theorem in Quantum Mechanics
Quantum manifestations of the dynamics around resonant tori in perturbed
Hamiltonian systems, dictated by the Poincar\'e--Birkhoff theorem, are shown to
exist. They are embedded in the interactions involving states which differ in a
number of quanta equal to the order of the classical resonance. Moreover, the
associated classical phase space structures are mimicked in the
quasiprobability density functions and their zeros.Comment: 5 pages, 3 figures, Full resolution figures available at
http://www.df.uba.ar/users/wisniaki/publications.htm
The Structure of a Biologically Active Influenza Virus Ribonucleoprotein Complex
The influenza viruses contain a segmented, single-stranded RNA genome of negative polarity. Each RNA segment is encapsidated by the nucleoprotein and the polymerase complex into ribonucleoprotein particles (RNPs), which are responsible for virus transcription and replication. Despite their importance, information about the structure of these RNPs is scarce. We have determined the three-dimensional structure of a biologically active recombinant RNP by cryo-electron microscopy. The structure shows a nonameric nucleoprotein ring (at 12 Ã… resolution) with two monomers connected to the polymerase complex (at 18 Ã… resolution). Docking the atomic structures of the nucleoprotein and polymerase domains, as well as mutational analyses, has allowed us to define the interactions between the functional elements of the RNP and to propose the location of the viral RNA. Our results provide the first model for a functional negative-stranded RNA virus ribonucleoprotein complex. The structure reported here will serve as a framework to generate a quasi-atomic model of the molecular machine responsible for viral RNA synthesis and to test new models for virus RNA replication and transcription
Osteomielitis crónica de extremidades inferiores en pacientes ancianos: colgajo sóleo, una opción efectiva
La osteomielitis crónica (OC) en extremidades inferiores afecta al hueso y tejidos blandos circundantes, produciéndose úlceras crónicas que exponen el hueso necrosado. El tratamiento de la OC combina: antibióticos, desbridamiento-estabilización ósea, y una adecuada cobertura cutánea. La reconstrucción de las pérdidas de sustancia localizadas en el tercio medio de la pierna puede realizarse con colgajos fasciocutáneos, colgajos libres, colgajos en piernas cruzadas y colgajos locales musculares. La edad avanzada del paciente es un factor importante a considerar para la indicación de la técnica reparadora. El colgajo sóleo tiene múltiples ventajas: rica vascularización, corto tiempo quirúrgico, postoperatorio cómodo para el paciente y mÃnima limitación funcional. Presentamos 2 casos de pacientes ancianos con defectos osteocutáneos tibiales secundarios a OC, en ambos casos la cobertura del defecto se realizó con el colgajo muscular sóleo, la evolución clÃnica fue favorable y la recuperación funcional total.Cronic osteomyelitis (CO) in lower legs involves
tibial-fibular bones and soft tissues around, with cronic ulcers
by necrosed bone exposure. CO treatment combines: antibiotics, removes necrotic bone, bony stabilization and an adequate soft tissue coverage. Soft tissue loss reconstruction in
the medium third of the legs can be made with fasciocutaneous flaps, free flaps, cross leg flaps and local muscle flaps.
Elderly age is an important condition for the reconstruction
procedure indication. Soleus muscle flap has multiple advantages: great blood supply, short surgical time, comfortable
postoperative and minimum functional sequels. Two cases:
Both elderly patients with osteocutaneous defects in tibia, by
CO. Treatment coverage was performed with soleus muscle
flap. Clinic course increased positively and the patients got
completely functional restitution
Traumatismos de partes blandas en la muñeca: cobertura fasciocutánea
Las pérdidas de sustancia traumática localizadas en la muñeca afectan frecuentemente a los tendones, vasos y nervios. Estas lesiones requieren un tratamiento reparador de las estructuras lesionadas y una cobertura adecuada que permita el deslizamiento de los tendones, y proporcione protección neurovascular segura. El colgajo fasciocutáneo basado en perforantes de la arteria cubital aporta piel, tejido subcutáneo y fascia sobre las estructuras expuestas en la muñeca tanto en la cara palmar como dorsal. Presentamos cuatro casos de traumatismos de partes blandas en la muñeca, en ellos tras la reparación neurotendinosa requerida, se optó por la cobertura final mediante el colgajo fasciocutáneo cubito-dorsal. Destacamos la versatilidad de estos colgajos, su fácil ejecución, mÃnima secuela estética y la posibilidad de iniciar precozmente el tratamiento rehabilitador, consiguiendo asà una mejor recuperación funcional del paciente.Traumatic soft tissue loss in wrist usually involves
tendons, vessels and nerves. These injuries need the adequate reconstructive treatment and the safe coverage which
lets to slide the tendons and it gives a safe protection to neurovascular structures. The fasciocutaneous flap based in perforator branches of the ulnar artery brings skin, fat and fascia
enough over the exposed tissues in the dorsal or volar surface of the wrist.
We report four cases of traumatic lesions in soft tissues of the
wrist, in all of them the fasciocutaneous dorsal cubital flap
was the option for the end coverage.
We emphasize the versatility of these flaps, its easy ejecution,
the minimal aesthetic sequel and the early rehabilitation beginning, so we obtain the best functional restitution for the patien
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