908 research outputs found

    Boundary quantum critical phenomena with entanglement renormalization

    Get PDF
    We extend the formalism of entanglement renormalization to the study of boundary critical phenomena. The multi-scale entanglement renormalization ansatz (MERA), in its scale invariant version, offers a very compact approximation to quantum critical ground states. Here we show that, by adding a boundary to the scale invariant MERA, an accurate approximation to the critical ground state of an infinite chain with a boundary is obtained, from which one can extract boundary scaling operators and their scaling dimensions. Our construction, valid for arbitrary critical systems, produces an effective chain with explicit separation of energy scales that relates to Wilson's RG formulation of the Kondo problem. We test the approach by studying the quantum critical Ising model with free and fixed boundary conditions.Comment: 8 pages, 12 figures, for a related work see arXiv:0912.289

    Use of Machine Learning Models of the ”Transformers” Type in the Construction of Services in a Gamified Web app.

    Get PDF
    The purpose of this document is to describe the use of a natural language processing model in the multiplatform system ”Gamivity” by means of a sentence similarity algorithm to offer a personalized experience module based on the conceptual relationship between questions. For the selection process, certain criteria were chosen that will allow several pre-trained models under the “Transformers” architecture for evaluation, later. These criteria were the language with which the model was altered; Python was the programming language used for the implementation. Regarding the evaluation phase of the selected models, the ”Sentence Transformers” library of the Python programming language was used. In addition, a work environment analogous to the module present in the ”Gamivity” system was built, in which the development platform ”Google Colab” was used to test these models. The criteria for choosing the candidate model were based on its effectiveness in relation to questions as well as the computational cost involved while performing the operations in the said model Based on the applied methodology, the model that yielded the best results was ”paraphrase-multilingual- MiniLM-L12-v2,” modified with a large corpus of text in Spanish and 50 other languages, which showed a degree of precision. When it comes to conceptually relating the questions provided it was found to be optimal, having relatively low computational cost when performing these operations. Keywords: sentence transformers, sentence similarity, relate questions, personalized learning. Resumen El presente documento, tiene como propósito el de describir la utilización de un modelo de procesamiento de lenguaje natural en el sistema multiplataforma “Gamivity”, por medio de un algoritmo de similitud de oraciones para ofrecer un módulo de experiencia personalizada a partir de la relación conceptual entre preguntas. Para el proceso de selección, se establecieron ciertos criterios que permitieron elegir varios modelos pre entrenados bajo la arquitectura “Transformers” para su posterior evaluación. Dichos criterios, fueron el idioma con el que fue entrenado el modelo, así como que el lenguaje de programación utilizado para la implementación fuese Python. En lo que concierne a la fase de evaluación de los modelos seleccionados, se hizo uso de la biblioteca “Sentence Transformers” del lenguaje de programación Python, además se construyó un entorno de trabajo análogo al módulo presente en el sistema “Gamivity”, en la plataforma de desarrollo “Google Colab” para poner a prueba dichos modelos, los criterios para la elección del modelo candidato, se resumen en la eficacia a la hora de relacionar preguntas, así como el coste computacional a la hora de realizar las operaciones involucradas en dicho proceso. A partir de la metodología aplicada, el modelo que mejor resultados generó fue “paraphrase-multilingual-MiniLM L12-v2”, entrenado con un gran corpus de texto en español, así como de otros 50 idiomas, el cual mostró un grado de precisión óptimo a la hora de relacionar conceptualmente las preguntas proporcionadas, así como su relativo bajo coste computacional a la hora de efectuar dichas operaciones. Palabras Clave: sentence transformers, sentence similarity, relacionar preguntas, aprendizaje personalizado

    Peri-implantitis, systemic inflammation, and dyslipidemia: a cross-sectional biochemical study

    Get PDF
    Purpose: The aim of this study was to compare the inflammatory and lipid profile of patients with and without peri-implantitis. / Methods: A cross-sectional biochemical study was carried out in which blood samples were collected from 16 patients with peri-implantitis and from 31 subjects with healthy implants. Clinical peri-implant parameters were obtained from all subjects. Levels of tumor necrosis factor-alpha and interleukin-10 (IL-10) were measured in serum. Lipid fractions, glucose and creatinine levels, and complete blood count were also assessed. / Results: After controlling for a history of periodontitis, statistically significant differences between peri-implantitis patients and controls were found for total cholesterol (estimated adjusted mean difference, 76.4 mg/dL; 95% confidence interval [CI], 39.6, 113.2 mg/dL; P<0.001), low-density lipoprotein (LDL) cholesterol (estimated adjusted mean difference, 57.7 mg/dL; 95% CI, 23.8, 91.6 mg/dL; P<0.001), white blood cells (WBC) (estimated adjusted mean difference, 2.8×103/μL; 95% CI, 1.6, 4.0×103/μL; P<0.001) and IL-10 (estimated adjusted mean difference, −10.4 pg/mL; 95% CI, −15.8, −5.0 pg/mL; P<0.001). The peri- implant probing pocket depth (PPD) was modestly positively correlated with total cholesterol (r=0.512; P<0.001), LDL cholesterol (r=0.463; P=0.001), and WBC (r=0.519; P<0.001). A moderate negative correlation was observed between IL-10 and PPD (r=0.609; P<0.001). / Cardiovascular diseases; Dyslipidemias; Peri-implantitis; Inflammation; Leukocytes Conclusions: Otherwise healthy individuals with peri-implantitis showed increased low- grade systemic inflammation and dyslipidemia

    Participatory Market Chains and Stakeholder Platforms: The Papa Andina strategy.

    Get PDF

    Mosaic: making biological sense of complex networks

    Get PDF
    Summary: We present a Cytoscape plugin called Mosaic to support interactive network annotation, partitioning, layout and coloring based on gene ontology or other relevant annotations

    On the Use of Finite-Size Scaling to Measure Spin-Glass Exponents

    Full text link
    Finite-size scaling (FSS) is a standard technique for measuring scaling exponents in spin glasses. Here we present a critique of this approach, emphasizing the need for all length scales to be large compared to microscopic scales. In particular we show that the replacement, in FSS analyses, of the correlation length by its asymptotic scaling form can lead to apparently good scaling collapses with the wrong values of the scaling exponents.Comment: RevTeX, 5 page

    African genomes illuminate the early history and transition to selfing in Arabidopsis thaliana

    Get PDF
    Over the past 20 y, many studies have examined the history of the plant ecological and molecular model, Arabidopsis thaliana, in Europe and North America. Although these studies informed us about the recent history of the species, the early history has remained elusive. In a large-scale genomic analysis of African A. thaliana, we sequenced the genomes of 78 modern and herbarium samples from Africa and analyzed these together with over 1,000 previously sequenced Eurasian samples. In striking contrast to expectations, we find that all African individuals sampled are native to this continent, including those from sub-Saharan Africa. Moreover, we show that Africa harbors the greatest variation and represents the deepest history in the A. thaliana lineage. Our results also reveal evidence that selfing, a major defining characteristic of the species, evolved in a single geographic region, best represented today within Africa. Demographic inference supports a model in which the ancestral A. thaliana population began to split by 120-90 kya, during the last interglacial and Abbassia pluvial, and Eurasian populations subsequently separated from one another at around 40 kya. This bears striking similarities to the patterns observed for diverse species, including humans, implying a key role for climatic events during interglacial and pluvial periods in shaping the histories and current distributions of a wide range of species
    corecore