Hysteresis in One-Dimensional Anti-Ferromagnetic Random-Field Ising Model at Zero-Temperature

We analyse hysteresis in a one-dimensional anti-ferromagnetic random field Ising model at zero-temperature. The random field is taken to have a rectangular distribution of width $2 \Delta$ centered about the origin. A uniform applied field is varied slowly from $-\infty$ to $+\infty$ and back. Analytic expression for the hysteresis loop is obtained in the case $\Delta \le |J|$, where $|J|$ is the strength of the nearest neighbor interaction

Interleuquina 6 y viremia de SARS-CoV-2 como marcadores de gravedad en pacientes ingresados con COVID-19

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Medicina. Fecha de Lectura: 22-04-2024Más de tres años después del inicio de la pandemia por SARS-CoV-2, el virus sigue estando presente en nuestras vidas y en el día a día de los diferentes niveles asistenciales sanitarios. A pesar del esfuerzo de investigadores de todo el mundo, uno de los retos sigue siendo el poder establecer el pronóstico de los pacientes desde fases tempranas de la enfermedad, ya que el cuadro clínico de la COVID-19 es muy heterogéneo, yendo desde los casos asintomáticos hasta el distrés respiratorio y la muerte. Por ello y para poder diseñar una estrategia terapéutica adecuada a cada paciente, es importante disponer de biomarcadores que nos permitan clasificar a los pacientes en función del riesgo desde los primeros días de infección. A este respecto, el objetivo principal de esta tesis es poder evaluar el papel como biomarcadores pronósticos en la COVID-19 tanto de la interleuquina 6 (IL6) como de la presencia de ARN de SARS-CoV-2 en sangre periférica (viremia). Igualmente, se estudió la cinética de ambas y los factores asociados a la aparición de viremia. Para responder a los objetivos de esta tesis, se diseñaron 4 estudios observacionales, 3 de ellos retrospectivos y uno prospectivo. Los resultados obtenidos han permitido establecer la utilidad tanto de la IL6 como de la viremia de SARS-CoV-2 como marcadores de mal pronóstico en pacientes hospitalizados con COVID-19. Niveles de IL6 por encima de 30 pg/ml fueron capaces de predecir la necesidad de ventilación mecánica no invasiva y la respuesta al tratamiento con tocilizumab, así como la supervivencia. Los pacientes con IL6 alta tratados precozmente con tocilizumab fueron los que presentaron mayor mejoría respiratoria. La viremia relevante de SARS-CoV-2 (por debajo de 34 Cts con la técnica de rRT-PCR de Roche y 31 Cts con ThermoFisher) predijo la mortalidad con alta sensibilidad pero baja especificidad. Aún así, la viremia fue mejor predictor que otros marcadores de inflamación. Por otro lado, en el estudio longitudinal, el único hasta el momento que ha comparado las cinéticas de la IL6 y la viremia, observamos que el pico de viremia fue más precoz que la elevación de IL6, sucediendo en los primeros 3-5 días tras el inicio de síntomas. Este hecho fue especialmente relevante en aquellos pacientes con criterios de gravedad, es decir, con viremia persistente o con IL6 alta. Finalmente, describimos por primera vez que variables clínicas como la edad, el sexo, la gravedad de la COVID-19 o la toma de IECAs o ARAII, y variantes genéticas como el rs2071746 en el gen HMOX1, rs78958998 en SERPING1, rs713400 en TMPRSS2, rs11052877 en CD69, rs33980500 TRAF3IP2, rs2660 en OAS1 y rs896 en VIPR1 se asociaron a la presencia de viremi

Von Karman correlation similarity in solar wind magnetohydrodynamic turbulence

A major development underlying hydrodynamic turbulence theory is the similarity decay hypothesis due to von Karman and Howarth, here extended empirically to plasma turbulence in the solar wind. In similarity decay the second-order correlation experiences a continuous transformation based on a universal functional form and a rescaling of energy and characteristic length. Solar wind turbulence follows many principles adapted from classical fluid turbulence, but previously this similarity property has not been examined explicitly. Here, we analyze an ensemble of Elsässer autocorrelation functions computed from Advanced Composition Explorer data at 1 astronomical unit (AU), and demonstrate explicitly that the two-point correlation functions undergo a collapse to a similarity form of the type anticipated from von Karman's hypothesis applied to weakly compressive magnetohydrodynamic turbulence. This provides a firm empirical basis for employing the similarity decay hypothesis to the Elsässer correlations that represent the incompressive turbulence cascade. This approach is of substantial utility in space turbulence data analysis, and for adopting von Karman-type heating rates in global and subgrid-scale dynamical modeling.Fil: Roy, Sohom. University Of Delaware; Estados UnidosFil: Chhiber, R.. University Of Delaware; Estados UnidosFil: Dasso, Sergio Ricardo. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Ruiz, Maria Emilia. Ministerio de Defensa. Secretaria de Planeamiento. Servicio Meteorológico Nacional; Argentina. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Matthaeus, W .H.. University Of Delaware; Estados Unido

Occurrence of SARS-CoV-2 viremia is associated with genetic variants of genes related to COVID-19 pathogenesis

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si lo hubiere, y los autores pertenecientes a la UAMSARS-CoV-2 viral load has been related to COVID-19 severity. The main aim of this study was to evaluate the relationship between SARS-CoV-2 viremia and SNPs in genes previously studied by our group as predictors of COVID-19 severity. Materials and methods: Retrospective observational study including 340 patients hospitalized for COVID-19 in the University Hospital La Princesa between March 2020 and December 2021, with at least one viremia determination. Positive viremia was considered when viral load was above the quantifiable threshold (20 copies/ml). A total of 38 SNPs were genotyped. To study their association with viremia a multivariate logistic regression was performed. Results: The mean age of the studied population was 64.5 years (SD 16.6), 60.9% patients were male and 79.4% white non-Hispanic. Only 126 patients (37.1%) had at least one positive viremia. After adjustment by confounders, the presence of the minor alleles of rs2071746 (HMOX1; T/T genotype OR 9.9 p < 0.0001), rs78958998 (probably associated with SERPING1 expression; A/T genotype OR 2.3, p = 0.04 and T/T genotype OR 12.9, p < 0.0001), and rs713400 (eQTL for TMPRSS2; C/T + T/T genotype OR 1.86, p = 0.10) were associated with higher risk of viremia, whereas the minor alleles of rs11052877 (CD69; A/G genotype OR 0.5, p = 0.04 and G/G genotype OR 0.3, p = 0.01), rs2660 (OAS1; A/G genotype OR 0.6, p = 0.08), rs896 (VIPR1; T/T genotype OR 0.4, p = 0.02) and rs33980500 (TRAF3IP2; C/T + T/T genotype OR 0.3, p = 0.01) were associated with lower risk of viremia. Conclusion: Genetic variants in HMOX1 (rs2071746), SERPING1 (rs78958998), TMPRSS2 (rs713400), CD69 (rs11052877), TRAF3IP2 (rs33980500), OAS1 (rs2660) and VIPR1 (rs896) could explain heterogeneity in SARS-CoV-2 viremia in our populatio

How do Older Adults Set Up Voice Assistants? Lessons Learned from a Deployment Experience for Older Adults to Set Up Standalone Voice Assistants.

While standalone Voice Assistants (VAs) are promising to support older adults daily routine and wellbeing management, onboarding and setting up these devices can be challenging. Although some older adults choose to seek assistance from technicians and adult children, easy set up processes that facilitate independent use are still critical, especially for those who do not have access to external resources. We aim to understand the older adults experience while setting up commercially available voice-only and voice-first screen-based VAs. Rooted in participants observations and semi-structured interviews, we designed a within-subject study with 10 older adults using Amazon Echo Dot and Echo Show. We identified the values of the built-in touchscreen and the instruction documents, as well as the impact of form factors, and outline important directions to support older adult independence with VAs

How do Older Adults Set Up Voice Assistants? Lessons Learned from a Deployment Experience for Older Adults to Set Up Standalone Voice Assistants

While standalone Voice Assistants (VAs) are promising to support older adults' daily routine and wellbeing management, onboarding and setting up these devices can be challenging. Although some older adults choose to seek assistance from technicians and adult children, easy set up processes that facilitate independent use are still critical, especially for those who do not have access to external resources. We aim to understand the older adults' experience while setting up commercially available voice-only and voice-first screen-based VAs. Rooted in participants observations and semi-structured interviews, we designed a within-subject study with 10 older adults using Amazon Echo Dot and Echo Show. We identified the values of the built-in touchscreen and the instruction documents, as well as the impact of form factors, and outline important directions to support older adult independence with VAs