14 research outputs found

    Solutions of the Strominger System via Stable Bundles on Calabi-Yau Threefolds

    Full text link
    We prove that a given Calabi-Yau threefold with a stable holomorphic vector bundle can be perturbed to a solution of the Strominger system provided that the second Chern class of the vector bundle is equal to the second Chern class of the tangent bundle. If the Calabi-Yau threefold has strict SU(3) holonomy then the equations of motion derived from the heterotic string effective action are also satisfied by the solutions we obtain.Comment: 19 pages, late

    Spread of a SARS-CoV-2 variant through Europe in the summer of 2020.

    Get PDF
    Following its emergence in late 2019, the spread of SARS-CoV-21,2 has been tracked by phylogenetic analysis of viral genome sequences in unprecedented detail3–5. Although the virus spread globally in early 2020 before borders closed, intercontinental travel has since been greatly reduced. However, travel within Europe resumed in the summer of 2020. Here we report on a SARS-CoV-2 variant, 20E (EU1), that was identified in Spain in early summer 2020 and subsequently spread across Europe. We find no evidence that this variant has increased transmissibility, but instead demonstrate how rising incidence in Spain, resumption of travel, and lack of effective screening and containment may explain the variant’s success. Despite travel restrictions, we estimate that 20E (EU1) was introduced hundreds of times to European countries by summertime travellers, which is likely to have undermined local efforts to minimize infection with SARS-CoV-2. Our results illustrate how a variant can rapidly become dominant even in the absence of a substantial transmission advantage in favourable epidemiological settings. Genomic surveillance is critical for understanding how travel can affect transmission of SARS-CoV-2, and thus for informing future containment strategies as travel resumes. © 2021, The Author(s), under exclusive licence to Springer Nature Limited

    Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020

    Get PDF
    We show the distribution of SARS-CoV-2 genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three available genomic nomenclature systems for SARS-CoV-2 to all sequence data from the WHO European Region available during the COVID-19 pandemic until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation. We provide a comparison of the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2.Peer reviewe

    Validación y fiabilidad de la versión española de la escala autoadministrada de Evaluación de Signos y Síntomas Neuropáticos de Leeds (S-LANSS)

    No full text
    Resumen: Introducción: La escala autoadministrada de Evaluación de Signos y Síntomas Neuropáticos de Leeds (S-LANSS) es un instrumento diseñado para identificar a pacientes con dolor de características neuropáticas. Objetivo: Evaluar la validez y fiabilidad de la versión española del S-LANSS. Métodos: Se incluyó un total de 182 pacientes con dolor crónico para evaluar la validez discriminante y convergente del S-LANSS, incrementándose la muestra hasta 321 pacientes para valorar la validez de constructo y la fiabilidad de la escala. Se utilizó como variable criterio la versión validada al español del ID-Pain. Todos los participantes cumplimentaron el cuestionario ID-Pain, el S-LANSS, y la Escala Numérica del Dolor. La validez discriminante se evaluó mediante el análisis del área bajo la curva de características operativas para el receptor, y la sensibilidad y especificidad. La validez de constructo se evaluó mediante un análisis factorial y mediante el análisis del odds-ratio de cada ítem del S-LANSS respecto a la puntuación total. La validez convergente y la fiabilidad se valoraron con la R de Pearson y el alfa de Cronbach respectivamente. Resultados: El punto de corte óptimo del S-LANSS fue ≥ 12 puntos (área bajo la curva = 0,89; sensibilidad = 88,7; especificidad = 76,6). El S-LANSS presentó un factor y, además, cada ítem contribuyó significativamente a la puntuación total positiva del S-LANSS (p < 0,05). El S-LANSS mostró una relación significativa con el ID-Pain (R = 0,734) y un alfa de Cronbach de 0,71. Conclusión: La versión española del S-LANSS es válida y fiable para identificar pacientes con dolor crónico con características neuropáticas. Abstract: Introduction: The self-administered Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) scale is a tool designed to identify patients with pain with neuropathic features. Objective: To assess the validity and reliability of the Spanish-language version of the S-LANSS scale. Methods: Our study included a total of 182 patients with chronic pain to assess the convergent and discriminant validity of the S-LANSS; the sample was increased to 321 patients to evaluate construct validity and reliability. The validated Spanish-language version of the ID-Pain questionnaire was used as the criterion variable. All participants completed the ID-Pain, the S-LANSS, and the Numerical Rating Scale for pain. Discriminant validity was evaluated by analysing sensitivity, specificity, and the area under the receiver operating characteristic curve (AUC). Construct validity was assessed with factor analysis and by comparing the odds ratio of each S-LANSS item to the total score. Convergent validity and reliability were evaluated with Pearson's r and Cronbach's alpha, respectively. Results: The optimal cut-off point for S-LANSS was ≥ 12 points (AUC = .89; sensitivity = 88.7; specificity = 76.6). Factor analysis yielded one factor; furthermore, all items contributed significantly to the positive total score on the S-LANSS (P < .05). The S-LANSS showed a significant correlation with ID-Pain (r = .734, α = .71). Conclusion: The Spanish-language version of the S-LANSS is valid and reliable for identifying patients with chronic pain with neuropathic features. Palabras clave: Dolor crónico, Dolor neuropático, Evaluación del dolor, Validez, Fiabilidad, Estudio transcultural, Keywords: Chronic pain, Neuropathic pain, Pain assessment, Validity, Reliability, Transcultural stud

    Pros and Cons of Clinical Basophil Testing (BAT)

    Get PDF
    PURPOSE OF REVIEW: We review basophil testing by flow cytometry with an emphasis on advantages and disadvantages. RECENT FINDINGS: There are many tools available to assess the presence and severity of allergic diseases in patients. For 50 years, peripheral blood basophils have been used as tools to study these diseases. It is a very accessible cell that binds IgE antibody and secretes the classical mediators responsible for the symptoms of allergic reactions. In the last decade, an even more accessible methodology, using flow cytometry, has been developed to enhance the ability to use basophils for both mechanistic and clinical diagnostics. Basophil testing has been included in diagnostics for different forms of allergies as well as to monitor disease status. A variety of studies have begun to establish both precise methods and their clinical relevance for disease diagnosis, but there remain some important questions on how to take optimal advantage of the behaviours of basophils
    corecore