Limits in the characteristic function description of non-Lindblad-type open quantum systems

In this paper I investigate the usability of the characteristic functions for the description of the dynamics of open quantum systems focussing on non-Lindblad-type master equations. I consider, as an example, a non-Markovian generalized master equation containing a memory kernel which may lead to nonphysical time evolutions characterized by negative values of the density matrix diagonal elements [S.M. Barnett and S. Stenholm, Phys. Rev. A {\bf 64}, 033808 (2001)]. The main result of the paper is to demonstrate that there exist situations in which the symmetrically ordered characteristic function is perfectly well defined while the corresponding density matrix loses positivity. Therefore nonphysical situations may not show up in the characteristic function. As a consequence, the characteristic function cannot be considered an {\it alternative complete} description of the non-Lindblad dynamics.Comment: Revised version. 4 pages, 1 figur

Doing transnational family im Kontext von Flucht und Krisenmigration: Stand der Forschung

In den vergangenen Jahren ist die Zahl gewaltsam Vertriebener stetig gestiegen, und auch die Anzahl der Menschen, die in weiter entfernte Staaten fliehen, hat laut UNHCR weltweit stark zugenommen. In Deutschland wurden im Zeitraum von 2015 bis 2017 fast 1,4 Mio. Asylerstanträge gestellt, hauptsächlich von Menschen aus Syrien, Afghanistan, Irak sowie Eritrea. Aufgrund der Aktualität des Themas hat sich seit Kurzem eine eigen-ständige Forschung zu Flucht und Geflüchteten in Deutschland entwickelt, wobei sich die deutsche Forschungslandschaft über die Disziplinen hinweg vor allem auf die Themen Aufnahme und Teilhabe von Geflüchteten in Deutschland konzentriert. Bisher gibt es nur sehr wenige Arbeiten, die sich mit Familien von Geflüchteten auseinandersetzen, obwohl unbestritten ist, dass Familien sowohl für die Migrationsentscheidung als auch für die Integration und Teilhabe im Zielland eine wichtige Rolle spielen. In Vorbereitung auf eine eigene empirische Studie, die diese Forschungslücke schließen möchte, wurde das vorliegende Working Paper erstellt. Es fasst die internationale Literatur zu den Fragen nach der Entstehung, Beibehaltung und Veränderung von transnationalen Familien, den transnationalen Alltagspraktiken sowie Unterstützungsleistungen und den Konsequenzen von Transnationalität auf die Beziehungsstabilität und -qualität zwischen Partnern, Kindern und Eltern sowie deren (subjektivem) Wohlbefinden, Einstellungen und Geschlechterrollen zusammen. Das Working Paper versucht darüber hinaus, die Anschlussfähigkeit der vorliegenden Studien zu transnationalen Familien auf den Fluchtkontext herzustellen und Forschungslücken im Themenfeld transnationaler Familien und Fluchtmigration aufzuzeigen

Upstream Statin Therapy and Long-Term Recurrence of Atrial Fibrillation after Cardioversion: A Propensity-Matched Analysis

The relationship of statin therapy with recurrence of atrial fibrillation (AF) after cardioversion (CV) has been evaluated by several investigations, which provided conflicting results and particularly long-term data is scarce. We sought to examine whether upstream statin therapy is associated with long-term recurrence of AF after CV. This was a single-center registry study including consecutive AF patients (n = 454) undergoing CV. Cox regression models were performed to estimate AF recurrence comparing patients with and without statins. In addition, we performed a propensity score matched analysis with a 1:1 ratio. Statins were prescribed to 183 (40.3%) patients. After a median follow-up period of 373 (207–805) days, recurrence of AF was present in 150 (33.0%) patients. Patients receiving statins had a significantly lower rate of AF recurrence (log-rank p < 0.001). In univariate analysis, statin therapy was associated with a significantly reduced rate of AF recurrence (HR 0.333 (95% CI 0.225–0.493), p = 0.001), which remained significant after adjustment (HR 0.238 (95% CI 0.151–0.375), p < 0.001). After propensity score matching treatment with statins resulted in an absolute risk reduction of 27.5% for recurrent AF (21 (18.1%) vs. 53 (45.7%); p < 0.001). Statin therapy was associated with a reduced risk of long-term AF recurrence after successful cardioversion

Redes Neuronales para predecir la aptitud del alumno y sugerir acciones

Debido a la recurrencia del problema presentado por los alumnos en lo que se refiere a su desempeño académico, se piensa en una aplicación de redes neuronales como apoyo al docente, al ser capaz de predecir las fallas de los estudiantes. Sobre esta predicción, se podrán establecer las actividades y acciones que el docente puede proponer al alumno para mejorar su desempeño. Para validar las hipótesis se adoptará un diseño cuasiexperimental. Las hipótesis a validar son: a) Una red neuronal puede predecir fallas de los alumnos en su desempeño. b) En base a sus propias predicciones, una red neuronal es capaz de determinar la clase de acciones a tomar por el docente para mejorar el desempeño del alumno. Se prevé la transferencia hacia la comunidad educativa del diseño instrumental, que dejará líneas de investigación abiertas de diversa complejidad para ser tratadas por investigadores formados y por tesistas de grado.Eje: Tecnología aplicada a la educaciónRed de Universidades con Carreras en Informática (RedUNCI

Redes Neuronales para predecir la aptitud del alumno y sugerir acciones

Debido a la recurrencia del problema presentado por los alumnos en lo que se refiere a su desempeño académico, se piensa en una aplicación de redes neuronales como apoyo al docente, al ser capaz de predecir las fallas de los estudiantes. Sobre esta predicción, se podrán establecer las actividades y acciones que el docente puede proponer al alumno para mejorar su desempeño. Para validar las hipótesis se adoptará un diseño cuasiexperimental. Las hipótesis a validar son: a) Una red neuronal puede predecir fallas de los alumnos en su desempeño. b) En base a sus propias predicciones, una red neuronal es capaz de determinar la clase de acciones a tomar por el docente para mejorar el desempeño del alumno. Se prevé la transferencia hacia la comunidad educativa del diseño instrumental, que dejará líneas de investigación abiertas de diversa complejidad para ser tratadas por investigadores formados y por tesistas de grado.Eje: Tecnología aplicada a la educaciónRed de Universidades con Carreras en Informática (RedUNCI

Siglec-6 is a novel target for CAR T-cell therapy in acute myeloid leukemia

Acute myeloid leukemia (AML) is an attractive entity for the development of chimeric antigen receptor (CAR) T-cell immunotherapy because AML blasts are susceptible to T-cell–mediated elimination. Here, we introduce sialic acid–binding immunoglobulin-like lectin 6 (Siglec-6) as a novel target for CAR T cells in AML. We designed a Siglec-6–specific CAR with a targeting domain derived from the human monoclonal antibody JML-1. We found that Siglec-6 is commonly expressed on AML cell lines and primary AML blasts, including the subpopulation of AML stem cells. Treatment with Siglec-6 CAR T cells confers specific antileukemia reactivity that correlates with Siglec-6 expression in preclinical models, including induction of complete remission in a xenograft AML model in immunodeficient mice (NSG/U937). In addition, we confirmed Siglec-6 expression on transformed B cells in chronic lymphocytic leukemia (CLL), and specific anti-CLL reactivity of Siglec-6 CAR T cells in vitro. Of particular interest, we found that Siglec-6 is not detectable on normal hematopoietic stem and progenitor cells (HSPCs) and that treatment with Siglec-6 CAR T cells does not affect their viability and lineage differentiation in colony-formation assays. These data suggest that Siglec-6 CAR T-cell therapy may be used to effectively treat AML without the need for subsequent allogeneic hematopoietic stem cell transplantation. In mature normal hematopoietic cells, we detected Siglec-6 in a proportion of memory (and naïve) B cells and basophilic granulocytes, suggesting the potential for limited on-target/off-tumor reactivity. The lack of expression of Siglec-6 on normal HSPCs is a key to differentiating it from other Siglec family members (eg, Siglec-3 [CD33]) and other CAR target antigens (eg, CD123) that are under investigation in AML, and it warrants the clinical investigation of Siglec-6 CAR T-cell therapy

COVID-19 patients share common, corticosteroid-independent features of impaired host immunity to pathogenic molds

Patients suffering from coronavirus disease-2019 (COVID-19) are susceptible to deadly secondary fungal infections such as COVID-19-associated pulmonary aspergillosis and COVID-19-associated mucormycosis. Despite this clinical observation, direct experimental evidence for severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2)-driven alterations of antifungal immunity is scarce. Using an ex-vivo whole blood stimulation assay, we challenged blood from twelve COVID-19 patients with Aspergillus fumigatus and Rhizopus arrhizus antigens and studied the expression of activation, maturation, and exhaustion markers, as well as cytokine secretion. Compared to healthy controls, T-helper cells from COVID-19 patients displayed increased expression levels of the exhaustion marker PD-1 and weakened A. fumigatus - and R. arrhizus -induced activation. While baseline secretion of proinflammatory cytokines was massively elevated, whole blood from COVID-19 patients elicited diminished release of T-cellular (e.g., IFN-γ, IL-2) and innate immune cell-derived (e.g., CXCL9, CXCL10) cytokines in response to A. fumigatus and R. arrhizus antigens. Additionally, samples from COVID-19 patients showed deficient granulocyte activation by mold antigens and reduced fungal killing capacity of neutrophils. These features of weakened anti-mold immune responses were largely decoupled from COVID-19 severity, the time elapsed since diagnosis of COVID-19, and recent corticosteroid uptake, suggesting that impaired anti-mold defense is a common denominator of the underlying SARS-CoV-2 infection. Taken together, these results expand our understanding of the immune predisposition to post-viral mold infections and could inform future studies of immunotherapeutic strategies to prevent and treat fungal superinfections in COVID-19 patients