¿Qué es en verdad el dinero? Una teoría sobre la naturaleza del dinero

Sorprende descubrir que no hay una definición de dinero que sea admitida deforma universal. No hay una explicación de la naturaleza del dinero que justifique todas sus funciones y características. Este trabajo pretende demostrar que el dinero es ante todo un derecho, y que considerarlo un derecho nos puede permitir aclarar los enigmas del dinero. Existe bastante acuerdo sobre para qué surge el dinero, pero debemos preguntarnos el cómo, y a partir del ahí explicar de dónde le vienen sus funciones y características, y su relación con el tiempo. Desde la experiencia que da el contacto con el dinero, se ha pretendido llegar a una explicación inteligible de su naturaleza que pueda justificar todo aquello que nos encontramos en la economía real, en las empresas y en los distintos mercados financieros y monetarios

Decoherence in a Josephson junction qubit

The zero-voltage state of a Josephson junction biased with constant current consists of a set of metastable quantum energy levels. We probe the spacings of these levels by using microwave spectroscopy to enhance the escape rate to the voltage state. The widths of the resonances give a measurement of the coherence time of the two states involved in the transitions. We observe a decoherence time shorter than that expected from dissipation alone in resonantly isolated 20 um x 5 um Al/AlOx/Al junctions at 60 mK. The data is well fit by a model including dephasing effects of both low-frequency current noise and the escape rate to the continuum voltage states. We discuss implications for quantum computation using current-biased Josephson junction qubits, including the minimum number of levels needed in the well to obtain an acceptable error limit per gate.Comment: 4 pages, 6 figure

Intraoperative ultrasound in conservative surgery for non-palpable breast cancer after neoadjuvant chemotherapy

AbstractAimsA complete clinical response after neoadjuvant chemotherapy (NACT) in breast cancer patients hinders the localization of the residual lesion and the removal of a minimum amount of breast tissue. The aim of the present work is to report our single-centre experience with intraoperative ultrasound-guided (IOUS) excision performed by surgeons in these patients.Patients and methodsFrom January 2008 to December 2012, IOUS excisions were performed on 58 patients with a previous intralesional ultrasound-detectable metallic marker and non-palpable breast cancer after NACT. The specimen margins were estimated by ultrasonography and macroscopic pathologic examination. Successful lesion removal, specimen weight, and analysis of the results as regards margins were evaluated, and the need for breast-conserving re-excision and mastectomy was considered.ResultsAfter NACT the average ultrasound/mammography and MRI diameters were 11.7 mm (0–30) and 9.1 mm (0–40) respectively. In all cases, the residual lesion or tissue around the marker was removed. The average weight of the specimens was 26.4 g (6–84), being lower in cases of complete response according to ultrasound (p < 0.05). In 4 patients (6.8%), breast-conserving re-excision was carried out, and in 3 patients (5.2%) a secondary mastectomy was performed, two of which had invasive lobular carcinoma.ConclusionsThe emplacement of a readily echodetectable metal marker before NACT makes IOUS excision feasible in an increasing number of complete clinical responses, with the excision of small amounts of breast tissue and a high percentage of conservative breast surgery. This technique requires surgeons to be trained, but has the advantage of a reduced use of other hospital services, better planning of operating theatres, and less discomfort for patients, which means that it is attractive and indeed recommendable

A possible Tsunami deposit associated to the CE 1755 Lisbon earthquake on the Western Coast of Portugal

The CE 1755 Lisbon tsunami was the largest historical tsunami to affect the Atlantic coasts of Europe and North Africa. This study presents the results obtained from the application of different sedimentological techniques (e.g., grain size, morphoscopy, microtextural analysis, geochemistry, radiocarbon dating) on sediments retrieved from the Alcabrichel River alluvial plain (of about 500 m far away from its mouth and approximatively 50 km northwest of Lisbon, Portugal). The results allowed the identification of a sandy layer that was associated with the CE 1755 tsunami. Furthermore, a new microtextural semi-quantitative classification was applied to enhance the identification of extreme marine inundation deposits. Based on sedimentological data, three different tsunami inundation phases were identified, including two inundations and a likely backwash. This innovative work offers physical evidence of the spatial presence of the CE 1755 tsunami event on the western coast of Europe. It also enables a reconstruction of tsunami inundation dynamics, with two flooding waves and an interspersed backwash.info:eu-repo/semantics/publishedVersio

Técnicas de cálculo de fase aplicadas à mecânica

Neste trabalho é realizado um estudo sobre o cálculo da distribuição espacial da fase com aplicação nas principais técnicas ópticas da Mecânica experimental: técnicas de Interferometria holográfica, Moiré interferométrico e caracterização de forma 3D. Todas estas técnicas para além de utilizarem a luz, para aceder à forma, ao deslocamento ou a deformação de objectos ou estruturas, recorrem também a métodos de cálculo de fase para melhorar a sua resolução, a qual, por sua vez, varia de técnica para técnica podendo em algumas delas ser ajustada ao problema em estudo

Second-order odd-harmonic repetitive control and its application to active filter control

High order repetitive control has been introduced toovercomeperformance decay of repetitive control systems undervarying frequency of the signals to be tracked/rejected orimproving the interhamonic behavior. However, most highorder repetitive internal models used to improve frequencyuncertainty are unstable, as a consequence practicalimplementations are more difficult. In this work a stable,second order odd-harmonic repetitive control system ispresented and studied.The proposed internal model has been implemented andvalidated in a shunt active filter current controller. Thishigh order controller allows dealing with the gridfrequency variations without using adaptive schemes

On the Usage of Linear Regression Models to Reconstruct Limb Kinematics from Low Frequency EEG Signals

Several works have reported on the reconstruction of 2D/3D limb kinematics from low-frequency EEG signals using linear regression models based on positive correlation values between the recorded and the reconstructed trajectories. This paper describes the mathematical properties of the linear model and the correlation evaluation metric that may lead to a misinterpretation of the results of this type of decoders. Firstly, the use of a linear regression model to adjust the two temporal signals (EEG and velocity profiles) implies that the relevant component of the signal used for decoding (EEG) has to be in the same frequency range as the signal to be decoded (velocity profiles). Secondly, the use of a correlation to evaluate the fitting of two trajectories could lead to overly-optimistic results as this metric is invariant to scale. Also, the correlation has a non-linear nature that leads to higher values for sinus/cosinus-like signals at low frequencies. Analysis of these properties on the reconstruction results was carried out through an experiment performed in line with previous studies, where healthy participants executed predefined reaching movements of the hand in 3D space. While the correlations of limb velocity profiles reconstructed from low-frequency EEG were comparable to studies in this domain, a systematic statistical analysis revealed that these results were not above the chance level. The empirical chance level was estimated using random assignments of recorded velocity profiles and EEG signals, as well as combinations of randomly generated synthetic EEG with recorded velocity profiles and recorded EEG with randomly generated synthetic velocity profiles. The analysis shows that the positive correlation results in this experiment cannot be used as an indicator of successful trajectory reconstruction based on a neural correlate. Several directions are herein discussed to address the misinterpretation of results as well as the implications on previous invasive and non-invasive works

Computational Model for Prediction of the Occurrence of Steam Pops during Irrigated Radiofrequency Catheter Ablation

Radiofrequency catheter ablation (RFCA) is a curative treatment for cardiac arrhythmias. Although globally a pretty safe procedure, it may present some risk. Steam pop is a serious complication that can occur during RFCA with irrigated electrodes. Pops are caused by tissue overheating above 89oC, and may cause explosive rupture of myocardial wall. Today, it is still very complicated to predict the occurrence and location of steam pops into the tissue during RFCA. Our aim was to use a computational model to address these issues considering two irrigated catheter tip designs and different power settings. The model has been validated against existing experimental results. Computational results show no evidence of significant differences in the incidence of steam pops between the two catheter designs. Steam pops appears at powers higher than 30W at approximately 2 mm depth under the electrode tip. Overall, the computational findings were in close agreement with previous experimental results, which suggests that the proposed model could be useful to predict the occurrence of steam pops in different clinical situations.MINECO TEC2014–52383-C3-R to E.B. and Generalitat Valenciana APOSTD/2016/045 to A.G.S

Aplicación del análisis de imagen a la caracterización de la marmatita l.t. (Marmato, Colombia)

El presente trabajo investiga la diferencia existente entre el contenido de Fe teórico definido en marmatita (esfalerita con 10% a 26% Fe) y el contenido real (9% Fe) determinado por Microsonda Electrónica (MS) en muestras de este mineral procedentes del locus typicus. Se trata de determinar si el mineral estaba correctamente definido en origen, combinando los estudios de MS y el Análisis Digital de Imagen (ADI) sobre probetas pulidas de la Mina de Marmato, Colombia. Se demuestra que las inclusiones microscópicas de otras fases portadoras de Fe (pirrotita, calcopirita) en esfalerita aportan una cantidad de Fe que puede ser significativa (~1.5 % en las muestras analizadas). Dichas fases no podían separarse cuando se definió la marmatita (1929) y, por tanto, el Fe de las mismas se habría atribuido a la esfalerita