Phase diagram of an extended Agassi model

Background: The Agassi model is an extension of the Lipkin-Meshkov-Glick model that incorporates the pairing interaction. It is a schematic model that describes the interplay between particle-hole and pair correlations. It was proposed in the 1960's by D. Agassi as a model to simulate the properties of the quadrupole plus pairing model. Purpose: The aim of this work is to extend a previous study by Davis and Heiss generalizing the Agassi model and analyze in detail the phase diagram of the model as well as the different regions with coexistence of several phases. Method: We solve the model Hamiltonian through the Hartree-Fock-Bogoliubov (HFB) approximation, introducing two variational parameters that play the role of order parameters. We also compare the HFB calculations with the exact ones. Results: We obtain the phase diagram of the model and classify the order of the different quantum phase transitions appearing in the diagram. The phase diagram presents broad regions where several phases, up to three, coexist. Moreover, there is also a line and a point where four and five phases are degenerated, respectively. Conclusions: The phase diagram of the extended Agassi model presents a rich variety of phases. Phase coexistence is present in extended areas of the parameter space. The model could be an important tool for benchmarking novel many-body approximations.Comment: Accepted for publication in PR

An extended Agassi model: algebraic structure, phase diagram, and large size limit

The Agassi model is a schematic two-level model that involves pairing and monopole-monopole interactions. It is, therefore, an extension of the well known Lipkin-Meshkov-Glick (LMG) model. In this paper we review the algebraic formulation of an extension of the Agassi model as well as its bosonic realization through the Schwinger representation. Moreover, a mean-field approximation for the model is presented and its phase diagram discussed. Finally, a $1/j$ analysis, with $j$ proportional to the degeneracy of each level, is worked out to obtain the thermodynamic limit of the ground state energy and some order parameters from the exact Hamiltonian diagonalization for finite$-j$.Comment: Accepted in Physica Scripta. Focus on SSNET 201

Effectiveness of a program of romana’s Pilates for non-specific low back pain: A pilot study

Objetivo: comprobar la efectividad del método Pilates Romana para conseguir una mayor flexibilidad de la columna, junto con una mejora en la movilidad de la misma, así como del dolor que presentan en su vida diaria los pacientes. Metodología: ensayo clínico con intención de tratar a treinta pacientes con dolor lumbar inespecífico. Asistieron a 15 sesiones, 2 veces a la semana, del Método Pilates Romana.. Se evaluaron parámetros tales como dolor, test de Schöber, SRS-22 y distancia dedos- suelo. Resultados. Se encontraron diferencias estadísticamente significativas con respecto al dolor (escala EVA), distancia dedos- suelo, test de Schöber (flexibilidad en plano sagital), flexión lateral (flexibilidad en plano frontal) y en varios ítems de la escala SRS-22, con valores de p<0,001. Por ello, este método puede ser usado para mejorar el dolor, la flexibilidad axial, la función y los aspectos relacionados con la calidad de vidaAim: to test the effectiveness of the Romana’s Pilates method to obtain increased flexibility, improvements in mobility, and reduced pain in daily life. Methodology: a clinical trial with intention-to-treat thirty patients with nonspecific low back pain. Participants attended 15 sessions, twice a week. The Romana’s Pilates method was taught by an external physiotherapist. Parameters such as pain, the Schober test, and the SRS-22 were evaluated. Results: Statistically significant differences in pain (VAS), the Schober test (flexibility in sagittal plane), lateral flexion (flexibility in frontal plane) and several items of the SRS-22 scale were found, with p <0.001. This method may be used to improve pain, axial flexibility, function and aspects related to the quality of life of patient

Point defects on graphene on metals

Understanding the coupling of graphene with its local environment is critical to be able to integrate it in tomorrow's electronic devices. Here we show how the presence of a metallic substrate affects the properties of an atomically tailored graphene layer. We have deliberately introduced single carbon vacancies on a graphene monolayer grown on a Pt(111) surface and investigated its impact in the electronic, structural and magnetic properties of the graphene layer. Our low temperature scanning tunneling microscopy studies, complemented by density functional theory, show the existence of a broad electronic resonance above the Fermi energy associated with the vacancies. Vacancy sites become reactive leading to an increase of the coupling between the graphene layer and the metal substrate at these points; this gives rise to a rapid decay of the localized state and the quenching of the magnetic moment associated with carbon vacancies in free-standing graphene layers

Threading Through Macrocycles Enhances the Performance of Carbon Nanotubes as Polymer Fillers

In this work we study the reinforcement of polymers by mechanically interlocked derivatives of single-walled carbon nanotubes (SWNTs). We compare the mechanical properties of fibers made of polymers and of composites with pristine single-walled carbon nanotubes (SWNTs), mechanically interlocked derivatives of SWNTs (MINTs) and the corresponding supramolecular models. Improvements of both Young's modulus and tensile strength of up to 200 % were observed for the polystyrene-MINTs samples with an optimized loading of just 0.01 wt.%, while the supramolecular models with identical chemical composition and loading showed negligible or even detrimental influence. This behavior is found for three different types of SWNTs and two types of macrocycles. Molecular dynamics simulations show that the polymer adopts an elongated conformation parallel to the SWNT when interacting with MINT fillers, irrespective of the macrocycle chemical nature, whereas a more globular structure is taken upon facing with either pristine SWNTs or supramolecular models. The MINT composite architecture thus leads to a more efficient exploitation of the axial properties of the SWNTs and of the polymer chain at the interface, in agreement with experimental results. Our findings demonstrate that the mechanical bond imparts distinctive advantageous properties to SWNT derivatives as polymer fillers.Comment: 39 pages, 19 figure

Epidemiology of injuries in professional and amateur spanish paddle players

Se realizó un estudio epidemiológico descriptivo, observacional y retrospectivo, analizando la incidencia y las características de las lesiones sufridas por jugadores de pádel españoles profesionales y no profesionales. Se registraron las lesiones sufridas por 478 jugadores entre el 1 de enero y el 31 de diciembre de 2016. Se registraron datos sobre el número de lesiones, lesiones más frecuentes, distribución, tipo, ubicación, el momento en que ocurrieron y la causa de las lesiones que afectan el sistema locomotor. La tasa de lesiones en esta población fue de 2,75 lesiones por 1000 horas de exposición al riesgo. Las lesiones leves y aquellas con mecanismos de lesión intrínseca fueron las más frecuentes, y tuvieron lugar el final de la práctica deportiva. La extremidad inferior fue el área corporal más lesionada, y el tejido más lesionado fue el sistema musculo-tendinoso. A su vez, la epicondilitis fue la patología más comúnAn epidemiological study was conducted using retrospective, observational and descriptive methodologies. We sought to analyse the incidence and features of injuries sustained by professional and non-professional Spanish Padel players. In total, 478 injuries were registered in 2016 from January 1st to December 31st. We collected data on the number of injuries, the most frequent injuries, their distribution, type, location, the moment at which these occurred and the cause of the injuries affecting the locomotor system. We found that the injury rate in this population was 2.75 injuries per 1000 hours of risk exposure. The most frequent injuries were those which were mild or with mechanisms of intrinsic injury, and most occurred towards the end any given game or practice. The lower limb was the most frequently injured body area, and the most injured tissue was the muscle-tendinous system. In turn, epicondylitis was the most common patholog

Preschool teachers' well-being. Impact of relationships between happiness, emotional intelligence, affect, burnout, and engagement for their initial and permanent training

From a Positive Psychology model applied to Education, the objective is to analyze emotional and motivational competencies of 82 preschool teachers, using the TMMS-24, PANAS, UWES, SHS and MBI and to establish recommendations for teacher training and student’s well-being. High levels of happiness, commitment, emotional intelligence and positive affect were found. Results ratify relationships between emotional intelligence, positive affect, engagement and personal accomplishment observed by studies in that population. Strong correlations (p> .01) were found between clarity, repair and positive affect, repair and vigor, and between vigor, dedication, absorption, and personal accomplishment. The 40.6% of the variance in teacher well-being was explained by emotional intelligence and affective competencies, with positive affect and repair competence the most important to predict happiness level. These results allow us to identify the competencies that should be included in pre-service university plans and in permanent training centers.Desde un modelo de Psicología positiva aplicado a la Educación, el objetivo es analizar las competencias emocionales y motivacionales de 82 docentes de Infantil, utilizando las pruebas TMMS- 24, PANAS, UWES, SHS y MBI y establecer recomendaciones para la formación docente y el bienestar del alumnado. Se encontraron altos niveles de felicidad, compromiso laboral, inteligencia emocional y afecto positivo. Los resultados también ratifican, en esta población, las relaciones encontradas por otros estudios entre inteligencia emocional, afecto positivo, implicación en el trabajo y compromiso personal. Se encontraron altas correlaciones (p> ,01) entre claridad y reparación y afecto positivo, y entre reparación y energía, y entre energía, dedicación, absorción y compromiso personal. El 40,6% de la varianza del bienestar docente (felicidad) se explicó por las puntuaciones en inteligencia emocional y afecto, siendo la capacidad afectiva positiva y la de reparación emocional las que mejor predijeron el nivel en felicidad. Estos resultados permiten identificar las competencias que deberían incluirse en los planes universitarios y en los centros de formación permanente

Analysis of local and peripheral immune response developed in sheep experimentally infected with Toxoplasma gondii at different times of gestation

Trabajo presentado al: 4th International Meeting on Apicomplexa in Farm Animals. (11-14 October 2017 - Madrid, Spain).Toxoplasmosis is one the main infectious causes of reproductive failure in sheep where the time of gestation when sheep are infected affects the clinical and lesional outcome of the disease. In order to investigate the variations of local and peripheral immune responses during gestation, pregnant sheep were infected at early, mid and late gestation and subsequently culled at 2, 3 and 4 weeks post infection. In those sheep inoculated during the second term, serological antibodies were detected earlier and the increase in serological γ-IFN was higher than in the other infected animals. Regarding the local immune response at the placenta, infiltration of inflammatory cells was mainly found in the maternal septa, although it also invaded foetal mesenchyme adjacent to the lesions. The increase in the number of T lymphocytes was observed only in ewes infected during the second and last terms of gestation while the increase of B cells occurred in sheep infected at the first and second terms. The expression of iba-1 antigen by macrophages was more frequent after infection during the first term whereas macrophages expressing lysozyme, CD163 or calprotectin were more frequent in infections at mid-gestation. A significant increase in the transcription of γ-IFN, when compared to control animals, occurred after infections in the first and second term, while TNF-α and IL-10 transcription increased only in the second and last term, respectively. There were no differences when comparing transcription of cytokines between animals infected at different terms of gestation. This study shows that the time of gestation when infection occurs has a clear influence over the pathogenesis of ovine toxoplasmosis as a greater inflammatory response was found after inoculating sheep at the second term of gestation. This finding may explain the later invasion of the placenta by the parasite at early and mid gestation described in previous studies.This study was founded by AGL2016-75935-C2-2-R and LE080U16 research grants.Peer Reviewe

VineSens: An Eco-Smart Decision-Support Viticulture System

[Abstract] This article presents VineSens, a hardware and software platform for supporting the decision-making of the vine grower. VineSens is based on a wireless sensor network system composed by autonomous and self-powered nodes that are deployed throughout a vineyard. Such nodes include sensors that allow us to obtain detailed knowledge on different viticulture processes. Thanks to the use of epidemiological models, VineSens is able to propose a custom control plan to prevent diseases like one of the most feared by vine growers: downy mildew. VineSens generates alerts that warn farmers about the measures that have to be taken and stores the historical weather data collected from different spots of the vineyard. Such data can then be accessed through a user-friendly web-based interface that can be accessed through the Internet by using desktop or mobile devices. VineSens was deployed at the beginning in 2016 in a vineyard in the Ribeira Sacra area (Galicia, Spain) and, since then, its hardware and software have been tested to prevent the development of downy mildew, showing during its first season that the system can led to substantial savings, to decrease the amount of phytosanitary products applied, and, as a consequence, to obtain a more ecologically sustainable and healthy wine.Ministerio de Economía y Competitividad; TEC2013-47141-C4-1-RMinisterio de Economía y Competitividad; TEC2016-75067-C4-1-R