Symmetries of Lagrangian fibrations

We construct fiber-preserving anti-symplectic involutions for a large class of symplectic manifolds with Lagrangian torus fibrations. In particular, we treat the K3 surface and the quintic threefold. We interpret our results as corroboration of the view that in homological mirror symmetry, an anti-symplectic involution is the mirror of duality. In the same setting, we construct fiber-preserving symplectomorphisms that can be interpreted as the mirror to twisting by a holomorphic line bundle.Comment: 45 page

Postorbital Discard and Chain of Custody: The Processing of Artifacts Returning to Earth from the International Space Station

Few items that comprise the material culture of the International Space Station ever return to Earth. Most are left on the station or placed on cargo resupply ships that burn up on atmospheric re-entry. This fact presents a challenge for archaeologists who use material culture as their primary evidence. Together with a sociologist, we observed the processes that have been developed by NASA contractors to handle and return items that come back to Earth on the Cargo Dragon vehicle. We observed two missions, CRS-13 and CRS-14, in January and May 2018, respectively, traveling to the locations of work and interviewing the contractors and associated staff. These observations are described here, using the lenses of archaeological understandings of discard practices, the anthropological concept of the chaîne opératoire, and the forensic idea of “chain of custody” to interpret the meanings and associations of the various kinds of objects returned from space

Remodelado estructural y de GAP Junctions en un modelo 3D de aurícula humana

Introducción:la fibrilación auricular (AF), es la más común de la arritmia cardiaca sostenida y un factor de riesgo para el accidente cerebro vascular y otras morbilidades, si no es tratada. Estudios epidemiológicos muestran que la AF tiende a perpetuarse con el tiempo, generando cambios electrofisiológicos y anatómicos denominados: remodelados auriculares. Se ha demostrado que estos cambios provocan variaciones de la velocidad de conducción (CV), en el tejido auricular. Objetivo:estudiar el efecto del remodelado de gap junctions en la propagación del potencial de acción, implementando un modelo 3D de aurícula humana altamente realista. Materiales y Métodos:se incorporaron los cambios generados por el remodelado eléctrico a un modelo de potencial de acción (AP) de miocito auricular, acoplado con un modelo tridimensional anatómicamente realista de aurícula humana dilatada. Mediante simulaciones de la propagación del AP en condiciones de remodelado eléctrico y anatómico, y de remodelado de gap junctions, se midieron las ventanas vulnerables de generación de reentradas en la base de las venas pulmonares izquierdas de la aurícula. Resultados:los resultados obtenidos indican que la ventana vulnerable en el remodelado de gap junctions, se desplazó 38 ms con relación al modelo dilatado, lo que nos muestra el impacto de la dilatación con remodelado de gap junction. Conclusiones:el remodelado eléctrico generó una disminución del 70 % en la duración del potencial de acción y una disminución de las velocidades de conducción entre un 14.6 y un 26 %, que fueron medidas en diferentes regiones de la aurícula dilatada. El foco disparado en la base de las venas pulmonares izquierdas, generó un frente de onda que mantiene una actividad reentrante debido a la anatomía subyacente de las venas pulmonares.Introduction:Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a significant risk factor for cerebrovascular accident and other morbidities if left untreated. Epidemiological studies show that AF tends to persist over time, creating electrophysiological and anatomical changes called atrial remodeling. It has been shown that these changes result in variations in conduction velocity (CV) in the atrial tissue. Objective:to study the effect of remodeling of gap junctions in the propagation of the action potential by implementing a highly realistic 3D human atrial model. Materials and methods:the changes caused by electrical remodeling were incorporated in an atrial myocyte action potential (AP) model coupled with an anatomically realistic three-dimensional model of dilated human atria. Through simulations of the AP spread in variations of anatomical and electrical remodeling and of gap junctions remodeling, vulnerable windows of reentry generation were measured at the base of the atrium left pulmonary veins. Results:the results obtained indicate that vulnerable window in the gap junctions remodeling moved 38 ms in relation with the expanded model which shows the impact of the dilatation gap junction remodeling. Conclusions:the electrical remodeling produced 70% decrease in action potential duration and decreased conduction velocities between 14.6 and 26 %, which were measured in different regions of the dilated atrium. The focus shot at the base of the left pulmonary veins created a wave which maintains a reentering activity due to the underlying anatomy of the pulmonary veins

SYZ mirror symmetry for hypertoric varieties

We construct a Lagrangian torus fibration on a smooth hypertoric variety and a corresponding SYZ mirror variety using $T$-duality and generating functions of open Gromov-Witten invariants. The variety is singular in general. We construct a resolution using the wall and chamber structure of the SYZ base.Comment: v_2: 31 pages, 5 figures, minor revision. To appear in Communications in Mathematical Physic

Next generation bone tissue engineering: non-viral miR-133a inhibition using collagen-nanohydroxyapatite scaffolds rapidly enhances osteogenesis.

Bone grafts are the second most transplanted materials worldwide at a global cost to healthcare systems valued over $30 billion every year. The influence of microRNAs in the regenerative capacity of stem cells offers vast therapeutic potential towards bone grafting; however their efficient delivery to the target site remains a major challenge. This study describes how the functionalisation of porous collagen-nanohydroxyapatite (nHA) scaffolds with miR-133a inhibiting complexes, delivered using non-viral nHA particles, enhanced human mesenchymal stem cell-mediated osteogenesis through the novel focus on a key activator of osteogenesis, Runx2. This study showed enhanced Runx2 and osteocalcin expression, as well as increased alkaline phosphatase activity and calcium deposition, thus demonstrating a further enhanced therapeutic potential of a biomaterial previously optimised for bone repair applications. The promising features of this platform offer potential for a myriad of applications beyond bone repair and tissue engineering, thus presenting a new paradigm for microRNA-based therapeutics

Alimentación y abastecimiento de víveres entre las tropas patriotas de la Nueva Granada, 1811-1816

Examen del problema de la alimentación y abastecimiento de víveres de las tropas patrióticas de la Nueva Granada durante la Primera República. Palabras clave: Guerras de independencia, Nueva Granada, milicias patrióticas, abastos, alimentación. Study of the problem of feeding and foot supply of the Nueva Granada patriotic troops during the First Republic

Alimentación y abastecimiento de víveres entre las tropas patriotas de la Nueva Granada, 1811-1816

Examen del problema de la alimentación y abastecimiento de víveres de las tropas patrióticas de la Nueva Granada durante la Primera República. Palabras clave: Guerras de independencia, Nueva Granada, milicias patrióticas, abastos, alimentación. Study of the problem of feeding and foot supply of the Nueva Granada patriotic troops during the First Republic

Hydrophobic RWGS catalysts: Valorization of CO2-rich streams in presence of CO/H2O

Nowadays, the majority of the Reverse Water Gas Shift (RWGS) studies assume somehow model feedstock (diluted CO2/H2) for syngas production. Nonetheless, biogas streams contain certain amounts of CO/H2O which will decrease the obtained CO2 conversion values by promoting the forward WGS reaction. Since the rate limiting step for the WGS reaction concerns the water splitting, this work proposes the use of hydrophobic RWGS catalysts as an effective strategy for the valorization of CO2-rich feedstock in presence of H2O and CO. Over Fe-Mg catalysts, the different hydrophilicities attained over pristine, N- and B-doped carbonaceous supports accounted for the impact on the activity of the catalyst in presence of CO/H2O. Overall, the higher CO productivity (4.12 μmol/(min·m2)) attained by Fe-Mg/CDC in presence of 20 % of H2O relates to hindered water adsorption and unveil the use of hydrophobic surfaces as a suitable approach for avoiding costly pre-conditioning units for the valorization of CO2-rich streams based on RWGS processes in presence of CO/H2O