Suchergebnisse

Under the terms of the Creative Commons Attribution License 3.0 (CC-BY). ; We investigate the dynamic susceptibility of Fe4 single-molecule magnets with integer spin (S=5) in the form of pure crystals as well as diluted in crystals of isostructural, but nonmagnetic, Ga4 clusters. Below approximately 1 K, the spin-lattice relaxation becomes dominated by a temperature-independent process. The spin-lattice relaxation time τ measured in this >quantum regime> is 12 orders of magnitude shorter than the characteristic time scale of direct phonon-induced processes but agrees with the relaxation times of pure (i.e., not assisted by phonons) spin tunneling events. The present results show that the latter phenomenon, despite conserving the energy of the ensemble of electronic and nuclear spins, drives the thermalization of electronic spins at very low temperatures. The spin-lattice relaxation time scales with the concentration of Fe4, thus suggesting that the main effect of dipolar interactions is to block tunneling. The data show therefore no evidence for the contribution of collective phonon emission processes, such as phonon superradiance, to the spin-lattice relaxation. © 2014 American Physical Society. ; This paper has been partly funded by the Spanish MINECO (Grant No. MAT2009-13977-C03), the Gobierno de Aragón (project MOLCHIP), the European Union (ERANET project NanoSci-ERA: Nanoscience in European Research Area SMMTRANS), the Italian MIUR (PRIN2008 project) and the Université Joseph Fourier (Grenoble, France) through a visiting professorship to A.C. ; Peer Reviewed

This paper deals with pain anticipation experienced before medical procedures. our experimental results show that individuals with lower time discount factors are more prone to suffer pain in advance. We provide a framework to rationalize the connection between pain anticipation and impatience. in this set up, more impatient subjects, who only value very near events, mainly take into account the present negative effects of medical procedures (the costs), whereas more patient individuals have a net positive valuation of medical events, given that they are able to value both the cost incurred now and all the benefits to be accrued in the future. ; Este artículo trata de la anticipación del dolor experimentada antes de los procedimientos médicos. nuestros resultados experimentales muestran que los individuos con factor de descuento temporal más bajo son más proclives a sufrir dolor por adelantado. el artículo proporciona un marco en el que racionalizar la relación existente entre impaciencia y anticipación del dolor. en este marco, los sujetos más impacientes, que evalúan sólo los eventos muy próximos en el tiempo, focalizan su atención principalmente en los efectos negativos de los procedimientos médicos (sólo los costes), mientras que los individuos más pacientes tienen una valoración neta positiva de los actos médicos puesto que valoran tanto el coste en el que se incurre en el presente como los beneficios que se obtendrán en el futuro. ; Financial support from the Spanish Ministry of Science and Innovation (SEJ2007-62081 and ECO2009-09120 and CO2010-17049), the Government of Andalusia Project for Excellence in Research (P07.SEJ.02547), Gobierno Vasco-DEUI (IT-313-07) and the Women's Institute of Spain (2008.031).

This paper deals with pain anticipation experienced before medical procedures. Our experimental results show that individuals with lower discount factors are more prone to suffer pain in advance. We provide a framework to rationalize the connection between pain anticipation and impatience. In this set up, more impatient subjects, who only value very near events, take into account mainly the negative effects of medical procedures (just the costs) whereas more patient individuals have a net positive valuation of medical events (given that they value both the cost incurred now and all the benefits accrued in the future). ; Financial support from the Spanish Ministry of Science and Innovation (SEJ2007-62081 and ECO2009-09120), the Government of Andalusia Project for Excellence in Research (P07.SEJ.02547), Gobierno Vasco-DEUI (IT-313-07) and the Women's Institute of Spain (2008.031). (2008.031).

Trabajo presentado al 14th International Superconductive Electronics Conference (ISEC), celebrado en Cambridge, Massachusetts (EE. UU.) del 7 al 11 de julio de 2013.-- et al. ; We report the design and performance of thin-film microsusceptometers intended for magnetic measurements on samples at variable temperature down to the low mK range and excitation frequencies of up to about 1 MHz. The devices are realized as first-order gradiometers with two circular loops of 60 μm or 30 μm average diameter resulting in a total inductance of 360 pH or 250 pH, respectively. An integrated excitation coil generates a magnetic field with a sensitivity of 0.1 T/A at the sample position, whereas the Josephson junctions are located in a field-reduced area. The susceptometers are fabricated by a conventional Nb/AlOx/Nb trilayer process. In order to enhance the sensitivity to the level required for the measurement of sub-μm samples, an extra detection loop of about 450 nm inner diameter was integrated into one of the pickup loops by using a focused ion beam (FIB). We show that this device is able of detecting signals from very small permalloy samples. An improved susceptometer design for equipment with integrated nanoloops is also presented, for which a total inductance of 50 pH is predicted. ; This work was partly funded by the European Microkelvin Collaboration within the 7th Framework Programme of the European Commission (Grant number 228464), by the Spanish Ministry of Economy and Competitiveness (Grant MAT2012-38318-C03), and by the EMRP (EMRP: European Metrology Research Programme) project MetNEMS NEW08. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union. ; Peer reviewed