Stability and noise spectra of relative Loran-C frequency comparisons

Relative comparisons of Loran-C frequency transmissions between the master station of Catanzaro (Simeri Crichi) and the X, Z slave stations of Estartit (Spain) and Lampedusa (Italy) are carrying out by the GG LORSTA monitor station of the Mediterranean Sea Loran-C chain. These comparisons are able to emphasize the relative and, under certain conditions, the absolute rate of the emitting standard frequencies of the slave stations and some relevant statistical properties of the Loran-C Method for frequency transmission and time synchronization. The stability of each Loran-C frequency standard transmission is subject to perturbations, more or less known, due to the propagation medium and other causes. Following the Allan (1966) method for data processing, the performance of the relative rate of frequency of the transmissions of the X, Z slave stations are described calculating the standard deviation of a set of N frequency measurements from its mean averaged during sampling times. This standard deviation is designated as the measure of the stability of the Loran-C frequency transmission

Physical Resources for Quantum-enhanced Phase Estimation

We study the role of quantum entanglement (particle entanglement and mode entanglement) in optical phase estimation by employing the first and second quantization formalisms of quantum mechanics. The quantum Fisher information (QFI) is expressed as a function of the first and second order optical coherence functions. The resulting form of the QFI elucidates the deriving metrological resources for quantum phase estimation: field intensity and photon detection correlations. In addition, our analysis confirms that mode entanglement is not required for quantum-enhanced interferometry, whereas particle entanglement is a necessary requirement.Comment: 8 pages, 2 figures, 2 table

Self-calibrating tomography for multi-dimensional systems

We present a formalism for self-calibrating tomography of arbitrary dimensional systems. Self-calibrating quantum state tomography was first introduced in the context of qubits, and allows the reconstruction of the density matrix of an unknown quantum state despite incomplete knowledge of the unitary operations used to change the measurement basis. We show how this can be generalized to qudits, i.e. d-level systems, and provide a specific example for a V-type three-level atomic system whose transition dipole moments are not known. We show that it is always possible to retrieve the unknown state and process parameters, except for a set of zero measure in the state-parameter space.Comment: Revised version. 9 pages, 3 figure

Análisis de las calificaciones compartidas en la modalidad participativa de la evaluación colaborativa entre docente y estudiantes

Current trends in educational assessment in different branches of higher education share the common goal of uniting learning with assessment. Most approaches and theoretical and practical developments in this field revolve around four main factors: feedback, democratization, alignment and relevance. This paper proposes the use of co-assessment as a means of ensuring dialogue-based, democratic and fairer evaluations. With co-assessment, the responsibility is shared by the teacher and the students, who negotiate and agree on the appraisal of student tasks and, in this paper, also on the awarded mark. The aim of this study is to analyse the relationship between a series of jointly agreed marks, following the co-assessment of four tasks, and the marks that the teachers and students would each have individually awarded. Two teachers and 100 students participated in the study, which follows a correlational design and analyses significant statistical differences. The results show a strong correlation between the jointly agreed marks and those assigned individually by the teacher, even though statistically significant differences were found between them. Conversely, no statistically significant differences were identified between the joint marks and the marks assigned individually by the students. These results call for reflection on the real possibility of adapting shared grading methods to students in university frameworks, where the repercussions of awarded marks go far beyond formative goals.Dentro de la variedad existente en las tendencias actuales sobre la evaluación de estudiantes, se encuentra el propósito común de relacionar evaluación y aprendizaje. La retroalimentación, la democratización, la coherencia y la relevancia son cuatro tópicos aglutinadores sobre los que giran la mayoría de los planteamientos y avances teóricos y prácticos en este ámbito. Como forma concreta de cristalizar una evaluación dialógica, democrática y justa, se propone la modalidad participativa de la evaluación colaborativa en la que docentes y estudiantes se reparten la responsabilidad, negociando y consensuando de forma conjunta el valor de las tareas y en nuestro caso, también la calificación final. El propósito de este estudio, que ha involucrado a un total de 100 alumnos y 2 docentes, es precisamente la comprobación del grado de relación existente entre las calificaciones compartidas de 4 tareas universitarias con las que habrían aportado en solitario el docente y el grupo de estudiantes. Se ha seguido un diseño de investigación correlacional y se ha comprobado la existencia de diferencias significativas. Los resultados muestran la estrecha correlación entre las calificaciones compartidas y las calificaciones del docente, aunque se han hallado diferencias estadísticamente significativas entre estas. Por otro lado, no se han encontrado diferencias entre las calificaciones compartidas y las calificaciones de los estudiantes. Las repercusiones de estos resultados, hacen reflexionar, entre otras cuestiones, sobre la posibilidad real de ajustar dichas calificaciones abiertas a la participación de los estudiantes en contextos universitarios donde las repercusiones sobrepasan de largo el ámbito únicamente formativo

Prehabilitation Before Total Knee Arthroplasty Increases Strength and Function in Older Adults With Severe Osteoarthritis

Preparing for the stress of total knee arthroplasty (TKA) surgery by exercise training (prehabilitation) may improve strength and function before surgery and, if effective, has the potential to contribute to postoperative recovery. Subjects with severe osteoarthritis (OA), pain intractable to medicine and scheduled for TKA were randomized into a usual care (UC) group (n = 36) or usual care and exercise (UC + EX) group (n = 35). The UC group maintained normal daily activities before their TKA. The UC + EX group performed a comprehensive prehabilitation program that included resistance training using bands, flexibility, and step training at least 3 times per week for 4-8 weeks before their TKA in addition to UC. Leg strength (isokinetic peak torque for knee extension and flexion) and ability to perform functional tasks (6-minute walk, 30 second sit-to-stand repetitions, and the time to ascend and descend 2 flights of stairs) were assessed before randomization at baseline (T1) and 1 week before the subject\u27s TKA (T2). Repeated-measures analysis of variance indicated a significant group by time interaction (p \u3c 0.05) for the 30-second sit-to-stand repetitions, time to ascend the first flight of stairs, and peak torque for knee extension in the surgical knee. Prehabilitation increased leg strength and the ability to perform functional tasks for UC + EX when compared to UC before TKA. Short term (4-8 weeks) of prehabilitation was effective for increasing strength and function for individuals with severe OA. The program studied is easily transferred to a home environment, and clinicians working with this population should consider prehabilitation before TKA. [PUBLICATION ABSTRACT

Nanomechanical and structural properties of native cellulose under compressive stress

Cellulose is an important biopolymer with applications ranging from its use as an additive in pharmaceutical products to the development of novel smart materials. This wide applicability arises in part from its interesting mechanical properties. Here we report on the use of high pressure X-ray diffraction and Raman spectroscopy in a diamond anvil cell to determine the bulk and local elastic moduli of native cellulose. The modulus values obtained are 20 GPa for the bulk modulus and 200-355 and 15 GPa for the crystalline parts and the overall elastic (Young's) modulus, respectively. These values are consistent with those calculated from tensile measurements. Above 8 GPa, the packing of the cellulose chains within the fibers undergoes significant structural distortion, whereas the chains themselves remain largely unaffected by compression

Prevención de la endocarditis bacteriana en odontología infantil

El presente artículo trata de la prevención de la endocarditis bacteriana en odontología infantil. Consideramos que se trata de una patología grave que no se tiene en cuenta todo lo que desearíamos

Characterization of thioredoxin y, a new type of thioredoxin identified in the genome of Chlamydomonas reinhardtii

AbstractThe sequencing of the Arabidopsis genome revealed a multiplicity of thioredoxins (TRX), ubiquitous protein disulfide oxido-reductases. We have analyzed the TRX family in the genome of the unicellular green alga Chlamydomonas reinhardtii and identified eight different thioredoxins for which we have cloned and sequenced the corresponding cDNAs. One of these TRXs represents a new type that we named TRX y. This most probably chloroplastic TRX is highly conserved in photosynthetic organisms. The biochemical characterization of the recombinant protein shows that it exhibits a thermal stability profile and specificity toward target enzymes completely different from those of TRXs characterized so far

Managing family conflict and resilience. Results of a universal socio-educative family drugs prevention program developed in school settings

This paper assesses changes in family conflict and resilience among families participating in a socio-educative short universal drug prevention program (PCF-U 11-14). A pre-post test quasi experimental design with control and experimental groups was implemented with 275 families. The work addresses the convenience of family training in social and parenting skills to strengthen families’ capacity to cope with difficulties and boosting family cohesion, but it also highlights the need to research deeper into the factors that affect parent and adolescent conflict to create new training strategies for families.Este trabajo evalúa los cambios en los conflictos familiares y la resiliencia entre las familias que participan en un programa socioeducativo universal, de corta duración, para la prevención de drogas (PCFU 11-14). Se implementó un diseño cuasi experimental pre-post test con grupos control y experimental con 275 familias. Se aborda la conveniencia de la capacitación familiar en habilidades sociales y de crianza para fortalecer la capacidad de las familias para hacer frente a las dificultades y fomentar la cohesión familiar, pero también se destaca la necesidad de investigar más a fondo los factores que afectan al conflicto entre padres y adolescentes para crear nuevas estrategias de capacitación para familias

Multimodel Analysis of Future Land Use and Climate Change Impacts on Ecosystem Functioning

"Land use and climate changes both affect terrestrial ecosystems. Here, we used three combinations of Shared Socioeconomic Pathways and Representative Concentration Pathways (SSP1xRCP26, SSP3xRCP60, and SSP5xRCP85) as input to three dynamic global vegetation models to assess the impacts and associated uncertainty on several ecosystem functions: terrestrial carbon storage and fluxes, evapotranspiration, surface albedo, and runoff. We also performed sensitivity simulations in which we kept either land use or climate (including atmospheric CO2) constant from year 2015 on to calculate the isolated land use versus climate effects. By the 2080–2099 period, carbon storage increases by up to 87 ± 47 Gt (SSP1xRCP26) compared to present day, with large spatial variance across scenarios and models. Most of the carbon uptake is attributed to drivers beyond future land use and climate change, particularly the lagged effects of historic environmental changes. Future climate change typically increases carbon stocks in vegetation but not soils, while future land use change causes carbon losses, even for net agricultural abandonment (SSP1xRCP26). Evapotranspiration changes are highly variable across scenarios, and models do not agree on the magnitude or even sign of change of the individual effects. A calculated decrease in January and July surface albedo (up to ?0.021 ± 0.007 and ?0.004 ± 0.004 for SSP5xRCP85) and increase in runoff (+67 ± 6 mm/year) is largely driven by climate change. Overall, our results show that future land use and climate change will both have substantial impacts on ecosystem functioning. However, future changes can often not be fully explained by these two drivers and legacy effects have to be considered. © 2019. The Authors.