1,074 research outputs found
Broadband Printed Antenna for Radiofrequency Energy Harvesting
In this work a broadband UHF antenna with high inductive input impedance for radiofrequency energy harvesting is presented. It consists of a small feeding loop and a biconical radiating dipole. A prototype has been fabricated on a FR4 substrate and tested. Experimental results show a - 3dB power transmission bandwidth of about 135MHz (840MHz−975MHz)
The Rio Cuarto crater field re-visited: remote sensing imagery analysis and new field observations.
Accepted versio
Accelerating Quantum Decay by Multiple Tunneling Barriers
A quantum particle constrained between two high potential barriers provides a paradigmatic example of a system sustaining quasi-bound (or resonance) states. When the system is prepared in one of such quasi-bound states, the wave function approximately maintains its shape but decays in time in a nearly exponential manner radiating into the surrounding space, the lifetime being of the order of the reciprocal of the width of the resonance peak in the transmission spectrum. Naively, one could think that adding more lateral barriers would preferentially slow down or prevent the quantum decay since tunneling is expected to become less probable and due to quantum backflow induced by multiple scattering processes. However, this is not always the case and in the early stage of the dynamics quantum decay can be accelerated (rather than decelerated) by additional lateral barriers, even when the barrier heights are arbitrarily large. The decay acceleration originates from resonant tunneling effects and is associated to large deviations from an exponential decay law. We discuss such a counterintuitive phenomenon by considering the hopping dynamics of a quantum particle on a tight-binding lattice with on-site potential barriers
Anyonic symmetry, drifting potentials and non-Hermitian delocalization
We consider wave dynamics for a Schr\"odinger equation with a non-Hermitian
Hamiltonian satisfying the generalized (anyonic) parity-time
symmetry , where
and are the parity and time-reversal operators. For a stationary
potential, the anyonic phase just rotates the energy spectrum of
in complex plane, however for a drifting potential the energy
spectrum is deformed and the scattering and localization properties of the
potential show intriguing behaviors arising from the breakdown of the Galilean
invariance when . In particular, in the unbroken
phase the drift makes a scattering potential barrier reflectionless, whereas
for a potential well the number of bound states decreases as the drift velocity
increases because of a non-Hermitian delocalization transition.Comment: 7 pages, 5 figure
Randomized trial on adjuvant treatment with FOLFIRI followed by docetaxel and cisplatin versus 5-fluorouracil and folinic acid for radically resected gastric cancer
Some trial have demonstrated a benefit of adjuvant fluoropirimidine with or without platinum compounds compared with surgery alone. ITACA-S study was designed to evaluate whether a sequential treatment of FOLFIRI [irinotecan plus 5-fluorouracil/folinic acid (5-FU/LV)] followed by docetaxel plus cisplatin improves disease-free survival in comparison with 5-FU/LV in patients with radically resected gastric cancer.
Patients with resectable adenocarcinoma of the stomach or gastroesophageal junction were randomly assigned to either FOLFIRI (irinotecan 180 mg/m(2) day 1, LV 100 mg/m(2) as 2 h infusion and 5-FU 400 mg/m(2) as bolus, days 1 and 2 followed by 600 mg/m(2)/day as 22 h continuous infusion, q14 for four cycles) followed by docetaxel 75 mg/m(2) day 1, cisplatin 75 mg/m(2) day 1, q21 for three cycles (sequential arm) or De Gramont regimen (5-FU/LV arm).
From February 2005 to August 2009, 1106 patients were enrolled, and 1100 included in the analysis: 562 in the sequential arm and 538 in the 5-FU/LV arm. With a median follow-up of 57.4 months, 581 patients recurred or died (297 sequential arm and 284 5-FU/LV arm), and 483 died (243 and 240, respectively). No statistically significant difference was detected for both disease-free [hazard ratio (HR) 1.00; 95% confidence interval (CI): 0.85-1.17; P = 0.974] and overall survival (OS) (HR 0.98; 95% CI: 0.82-1.18; P = 0.865). Five-year disease-free and OS rates were 44.6% and 44.6%, 51.0% and 50.6% in the sequential and 5-FU/LV arm, respectively.
A more intensive regimen failed to show any benefit in disease-free and OS versus monotherapy
Sarcopenia: What a Surgeon Should Know
Sarcopenia is an increasingly frequent syndrome characterized by generalized and progressive loss of muscle mass, reduction in muscle strength, and resultant functional impairment. This condition is associated with increased risk of falls and fractures, disability, and increased risk of death. When a sarcopenic patient undergoes major surgery, it has a higher risk of complications and postoperative mortality because of less resistance to surgical stress. It is not easy to recognize a sarcopenic patient preoperatively, but this is essential to evaluate the correct risk to benefit ratio. The role of sarcopenia in surgical patients has been studied for both oncological and non-oncological surgery. For correct surgical planning, data about sarcopenia are essential to design a correct tailored treatment
Gorgias y Platón sobre lógos, persuasión y engaño
In Sophist 234b-c Plato characterizes the sophist as a maker of “spoken images”. In order to clarify this art of the sophist, an analogy is proposed between painting and sophistry. This analogy has been criticized as involving an illegitimate assimilation between visual and spoken images, or between the objects of seeing and statements/beliefs. I argue in this paper for a different interpretation. Plato deals with mímesis as a kind of making something (poiésis) rather than as a kind of acquiring something (ktêsis) that is or has already come into being. He focuses on the making prior to the product.En Sofista 234b-c, Platón caracteriza al sofista como fabricante de “imágenes habladas” (eídola legómena). Para esclarecer la arte que pratica, una analogía es propuesta entre el pintor y el sofista, pero esa analogía ha sido criticada por envolver una asimilación ilegítima entre imágenes visuales e habladas, o entre lo que es visto y lo dicho o creído. Intentaré mostrar en este texto, una interpretación diferente. Platón se refiere a la mímesis como una forma de producción (poíesis), a diferencia de la adquisición (ktêsis) de algo que ya es o que ha llegado a ser dirigiendo la atención al producir antes que al producto
ALGUNOS ASPECTOS DE LA CRÍTICA PLATÓNICA AL ARTE IMITATIVO – LA ANALOGÍA ENTRE EL SOFISTA Y EL PINTOR
In the Sophist 234b-c, Plato attempts to characterize the sophist as a maker of "spoken images". This analogy between painting and sophistry, which the dialogue proposes in order to clarify the art practiced by sophists, has been criticized as involving an illegitimate assimilation of visual to spoken images, or of the objects of seeing to those of stating/believing. However, as I try to demonstrate in this paper, a different interpretation is possible.No Sofista, 234b-c, Platão descreve o sofista como um criador de “imagens faladas”. Para esclarecer essa arte, é proposta uma analogia entre a pintura e a sofística. A analogia tem sido criticada por implicar assimilação ilegítima entre imagens visuais e faladas, ou entre objetos da visão e do enunciado/crença. De qualquer forma, tento demonstrar neste artigo que é possível uma interpretação diferente
Time lag between metamorphism and crystallization of anatectic granites (Córdoba, Argentina)
SHRIMP and LA-ICP-MS analyses carried out on zircons from the Río de los Sauces granite revealed their metamorphic and igneous nature. The metamorphic zircons yielded an age of 537±4.8 (2σ)Ma that probably predates the onset of the anatexis during the Pampean orogeny. By contrast, the igneous zircons yielded a younger age of 529±6 (2σ)Ma and reflected its crystallization age. These data point to a short time lag of ca. 8Myr between the High Temperature (HT) metamorphic peak and the subsequent crystallization age of the granite. Concordia age of 534±3.8 (2σ)Ma, for both types of zircon populations, can be considered as the mean age of the Pampean HT metamorphism in the Sierras de Córdoba
Time lag between metamorphism and crystallization of anatectic granites (Córdoba, Argentina)
SHRIMP and LA-ICP-MS analyses carried out on zircons from the Río de los Sauces granite revealed their metamorphic and igneous nature. The metamorphic zircons yielded an age of 537±4.8 (2σ)Ma that probably predates the onset of the anatexis during the Pampean orogeny. By contrast, the igneous zircons yielded a younger age of 529±6 (2σ)Ma and reflected its crystallization age. These data point to a short time lag of ca. 8Myr between the High Temperature (HT) metamorphic peak and the subsequent crystallization age of the granite. Concordia age of 534±3.8 (2σ)Ma, for both types of zircon populations, can be considered as the mean age of the Pampean HT metamorphism in the Sierras de Córdoba
- …
