203 research outputs found
Adiabatic quantum pump in the presence of external ac voltages
We investigate a quantum pump which in addition to its dynamic pump
parameters is subject to oscillating external potentials applied to the
contacts of the sample. Of interest is the rectification of the ac currents
flowing through the mesoscopic scatterer and their interplay with the quantum
pump effect. We calculate the adiabatic dc current arising under the
simultaneous action of both the quantum pump effect and classical
rectification. In addition to two known terms we find a third novel
contribution which arises from the interference of the ac currents generated by
the external potentials and the ac currents generated by the pump. The
interference contribution renormalizes both the quantum pump effect and the ac
rectification effect. Analysis of this interference effect requires a
calculation of the Floquet scattering matrix beyond the adiabatic approximation
based on the frozen scattering matrix alone. The results permit us to find the
instantaneous current. In addition to the current generated by the oscillating
potentials, and the ac current due to the variation of the charge of the frozen
scatterer, there is a third contribution which represents the ac currents
generated by an oscillating scatterer. We argue that the resulting pump effect
can be viewed as a quantum rectification of the instantaneous ac currents
generated by the oscillating scatterer. These instantaneous currents are an
intrinsic property of a nonstationary scattering process.Comment: 11 pages, 1 figur
¿Cómo diseñar, aplicar y evaluar un programa de Mentoring en enfermedad renal crónica? evaluación narrativa del impacto en 6 centros asistenciales
Antecedentes y objetivo
La enfermedad renal crónica (ERC) requiere de un proceso de adaptación en el paciente, que se puede facilitar con el apoyo de los profesionales sanitarios, asà como por iguales capacitados. El objetivo de este estudio es presentar la puesta en marcha de un programa piloto de paciente mentor para promover la adaptación de los pacientes con ERC.
Materiales y método
Diseño mixto (cuantitativo y cualitativo) pre-post. El estudio se llevó a cabo en 6 hospitales de España. Los instrumentos utilizados para medir el impacto fueron escalas elaboradas ad-hoc (formato de respuesta escala de Likert de 10 puntos) de satisfacción y adquisición de competencias, asà como la creación de grupos focales con 8 pacientes mentores y 10 profesionales sanitarios. Se dividió el programa en 4 fases: 1) Diseño y validación de contenidos del programa manualizado y selección de pacientes mentores; 2) Formación a mentores, satisfacción con la formación y competencias adquiridas por los mentores; 3) Implementación de los grupos de apoyo mutuo y perfil de los asistentes a los grupos de apoyo mutuo, y 4) Evaluación y resultados del programa de Mentoring.
Resultados
Se han formado a un total de 39 mentores en habilidades para conducción de grupos, asà como para facilitar apoyo emocional. Se han conducido 22 grupos de apoyo con 121 participantes (22% cuidadores). El 65% de los pacientes estaban en consulta de ERC. Un 65% de los pacientes participantes consideraron hacer algún cambio en su estilo de vida tras la asistencia al programa. Todos los Ãtems que evalúan satisfacción y utilidad han mostrado una puntuación muy elevada, por encima del valor 8, 5 sobre 10.
Conclusiones
Este es el primer programa manualizado de Mentoring en ERC llevado a cabo de manera simultánea en 6 hospitales españoles. La naturaleza del programa, manualizado y altamente estructurado, permite su replicabilidad minimizando el riesgo de error.
Background and objective
Chronic kidney disease (CKD) requires patients to participate in an adaptation process, which may be facilitated with the support of healthcare professionals and trained peers. The objective of this study is to present the implementation of a pilot patient mentoring programme to promote adaptation in patients with CKD.
Materials and method
Pre-test-post-test design (quantitative and qualitative). The study was carried out in six hospitals in Spain. The instruments used to measure impact were ad-hoc scales (10-point Likert scale response format) on satisfaction and skill acquisition, as well as the creation of focus groups with eight patient mentors and 10 healthcare professionals. The programme was split into four phases: 1. Design and validation of the manualised programme''s content, and selection of patient mentors; 2. Mentor training, satisfaction with training and skills acquired by the mentors; 3. Implementation of mutual support groups and profile of those attending these mutual support groups; 4. Assessment and results of the Mentoring programme.
Results
In total, 39 mentors were trained on group management skills, as well as how to provide emotional support. 22 support groups were held, with 121 participants (22% carers). The 65% of the patients were attending the CKD clinic. 65% of the participating patients considered making some form of lifestyle change after taking part in the programme. All the items assessing satisfaction and usefulness scored very highly, achieving 8.5 out of 10 or above.
Conclusions
This is the first manualised mentoring programme in CKD to be undertaken simultaneously in six Spanish hospitals. The manualised and highly structured nature of the programme make it easy to replicate, minimising the risk of error
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Search for double-β decay of 130Te to the first 0+ excited state of 130Xe with the CUORICINO experiment bolometer array
The CUORICINO experiment was an array of 62 TeO2 single-crystal bolometers with a total 130Te mass of 11.3kg. The experiment finished in 2008 after more than 3 yr of active operating time. Searches for both 0ν and 2ν double-β decay to the first excited 0+ state in 130Xe were performed by studying different coincidence scenarios. The analysis was based on data representing a total exposure of N(130Te)⋅t=9.5×1025yr. No evidence for a signal was found. The resulting lower limits on the half-lives are T2ν12(130Te→130Xe∗)\u3e1.3×1023yr (90% C.L.), and T0ν12(130Te→130Xe∗)\u3e9.4×1023yr (90% CL)
CUORE Experiment: The Search for Neutrrinoless Double Beta Decay
The main purpose of the Cryogenic Underground Observatory for Rare Events (CUORE) experiment is the search for the Neutrinoless Double Beta Decay (0νDBD) of n130Te reaching a sensitivity on Majorana mass better than 50 meV. Cuoricino represents not only the first stage of CUORE, but also the most massive 0νDBD experiment presently running. Present results and future planning of these experiments will be described in the paper
An active-shield method for the reduction of surface contamination in CUORE
The main goal of the CUORE experiment is to search for the neutrinoless double beta decay of 130Te. As it is a rare nuclear decay, the sensitivity of the experiment strongly depends on the background level in the transition energy region. In this paper we describe the R&D work performed to develop an active method for the reduction of radioactive background in CUORE. The idea is to reject events originated by surface contamination in large mass bolometric detectors by using bolometers sensitive to surface events. Results obtained with the first prototypes and tests made with large mass surface sensitive bolometers will be reported
History of clinical transplantation
How transplantation came to be a clinical discipline can be pieced together by perusing two volumes of reminiscences collected by Paul I. Terasaki in 1991-1992 from many of the persons who were directly involved. One volume was devoted to the discovery of the major histocompatibility complex (MHC), with particular reference to the human leukocyte antigens (HLAs) that are widely used today for tissue matching.1 The other focused on milestones in the development of clinical transplantation.2 All the contributions described in both volumes can be traced back in one way or other to the demonstration in the mid-1940s by Peter Brian Medawar that the rejection of allografts is an immunological phenomenon.3,4 © 2008 Springer New York
Perspectives of lowering CUORE thresholds with Optimum Trigger
CUORE is a cryogenic experiment that focuses on the search of neutrinoless double beta decay in 130Te and it is located at the Gran Sasso National Laboratories. Its detector consists of 988 TeO2 crystals operating at a base temperature of ~10 mK. It is the first ton-scale bolometric experiment ever realized for this purpose. Thanks to its large target mass and ultra-low background, the CUORE detector is also suitable for the search of other rare phenomena. In particular the low energy part of the spectra is interesting for the detection of WIMP-nuclei scattering reactions. One of the most important requirements to perform these studies is represented by the achievement of a stable energy threshold lower than 10 keV. Here, the CUORE capability to accomplish this purpose using a low energy software trigger will be presented and described
Search for 14.4 keV Solar Axions from M1 Transition of 57Fe with CUORE Crystals
We report the results of a search for axions from the 14.4 keV M1 transition from 57Fe in the core of the sun using the axio-electric effect in TeO2bolometers. The detectors are 5
× 5 × 5 cm3 crystals operated at about 10 mK in a facility used to test bolometers for the CUORE experiment at the Laboratori Nazionali del Gran Sasso in Italy. An analysis of 43.65 kg⋅d of data was made using a newly developed low energy trigger which was optimized to reduce the energy threshold of the detector. An upper limit of 0.58 c⋅kg−1⋅d−1 is established at 95% C.L., which translates into lower bounds fA ≥ 3.12 × 105 GeV 95% C.L. (DFSZ model) and fA ≥ 2.41 × 104 GeV 95% C.L. (KSVZ model) on the Peccei-Quinn symmetry-breaking scale, for a value of S = 0.5 of the flavor-singlet axial vector matrix element. These bounds can be expressed in terms of axion masses as mA ≤ 19.2 eV and mA ≤ 250 eV at 95% C.L. in the DFSZ and KSVZ models respectively. Bounds are given also for the interval 0.35 ≤ S ≤ 0.55
Results from the CUORE-0 experiment
The CUORE-0 experiment searched for neutrinoless double beta decay in 130Te using an array of 52 tellurium dioxide crystals, operated as bolometers at a temperature of 10 mK. It took data in the Gran Sasso National Laboratory (Italy) since March 2013 to March 2015. We present the results of a search for neutrinoless double beta decay in 9.8 kg-years 130Te exposure that allowed us to set the most stringent limit to date on this half-life. The performance of the detector in terms of background and energy resolution is also reported
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