Improving the 14c dating of marine shells from the Canary Islands for constructing more reliable and accurate chronologies

Radiocarbon dating of closely associated marine mollusk shells and terrestrial material (charred wood or bone) collected from archaeological contexts on Tenerife and Fuerteventura islands allowed us to quantify the marine C-14 reservoir effect (Delta R) around the Canary Archipelago. Coastal Fuerteventura has a positive weighted mean Delta R value of +185 +/- 30 C-14 yr, while for Tenerife a range of negative and positive values was obtained, resulting in a Delta R weighted mean value of 0 +/- 35 C-14 yr. These values are in accordance with the hydrodynamic system present off the Canary Islands characterized by a coastal upwelling regime that affects the eastern islands (Fuerteventura and Lanzarote) but not the other islands of the archipelago, namely Tenerife. Because of this oceanographic pattern, we recommend the extrapolation of these results to the remaining islands of the archipelago, i.e. the first value must be used for the eastern islands, while for the central and western islands the acceptable Delta R value is 0 +/- 35 C-14 yr

Gravitational waves from a Weyl-Integrable manifold: a new formalism

We study the variational principle over an Hilbert-Einstein like action for an extended geometry taking into account torsion and non-metricity. By extending the semi-Riemannian geometry, we obtain an effective energy-momentum tensor which can be interpreted as physical sources. As an application we develop a new manner to obtain the gravitational wave equations on a Weyl-integrable manifold taking into account the non-metricity and non-trivial boundary conditions on the minimization of the action, which can be identified as possible sources for the cosmological constant and provides two different equations for gravitational waves. We examine gravitational waves in a pre-inflationary cosmological model.Comment: Accepted in Physics of the Dark Univers

The Derived Deligne Conjecture

We study the operad of derived $A_\infty$-algebras from a new point of view in order to find a derived version of the Deligne conjecture. We start by defining the brace structure on an operad of graded $R$-modules using operadic suspension, which we describe in depth for the first time as a functor, and use it to define $A_\infty$-algebra structures on certain operads, with the endomorphism operad as our main example. This construction provides us with an operadic context from which $A_\infty$-algebras arise in a natural way and allows us to generalize the Lie algebra structure on the Hochschild complex of an $A_\infty$-algebra. Next, we generalize these constructions to operads of bigraded $R$-modules, introducing a totalization functor. This allows us to generalize a Lie algebra structure on the total complex of a derived $A_\infty$-algebra. This construction and the use of some enriched categories allow us to obtain new versions of the Deligne conjecture.Comment: 68 pages, submitted to La Matematica journal. arXiv admin note: text overlap with arXiv:1609.08077 by other author

GuaB Activity Is Required in Rhizobium tropici During the Early Stages of Nodulation of Determinate Nodules but Is Dispensable for the Sinorhizobium meliloti–Alfalfa Symbiotic Interaction

The guaB mutant strain Rhizobium tropici CIAT8999-10T is defective in symbiosis with common bean, forming nodules that lack rhizobial content. In order to investigate the timing of the guaB requirement during the nodule formation on the host common bean by the strain CIAT899-10.T, we constructed gene fusions in which the guaB gene is expressed under the control of the symbiotic promoters nodA, bacA, and nifH. Our data indicated that the guaB is required from the early stages of nodulation because full recovery of the wild-type phenotype was accomplished by the nodA-guaB fusion. In addition, we have constructed a guaB mutant derived from Sinorhizobium meliloti 1021, and shown that, unlike R. tropici, the guaB S. meliloti mutant is auxotrophic for guanine and induces wild-type nodules on alfalfa and Medicago truncatula. The guaB R. tropici mutant also is defective in its symbiosis with Macroptilium atropurpureum and Vigna unguiculata but normal with Leucaena leucocephala. These results show that the requirement of the rhizobial guaB for symbiosis is found to be associated with host plants that form determinate type of nodules.Fil: Collavino, Mónica Mariana. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Riccillo, Pablo M.. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; ArgentinaFil: Grasso, Daniel Horacio. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Crespi, Martín. Centre National de la Recherche Scientifique; FranciaFil: Aguilar, Orlando Mario. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; Argentin

Considerations on the physical and mechanical properties of lime-stabilized rammed earth walls and their evaluation by ultrasonic pulse velocity testing

This study examines the influence of moulding moisture content on the compressive strength, dry density and porosity of a rammed earth wall, using ultrasound as a complementary technique. Non-parametric and multivariate statistical techniques were applied to analyse the behaviour of variables with a sufficiently large population. The statistical analysis demonstrated that excessive or insufficient moulding moisture content directly determines the physical-mechanical properties of such walls. Ultrasound was confirmed as a valid technique for assessing the quality of a wall, since its response, albeit with certain limitations, was consistent with physical-mechanical properties

Role of Oxidative Stress in Transformation Induced by Metal Mixture

Metals are ubiquitous pollutants present as mixtures. In particular, mixture of arsenic-cadmium-lead is among the leading toxic agents detected in the environment. These metals have carcinogenic and cell-transforming potential. In this study, we used a two step cell transformation model, to determine the role of oxidative stress in transformation induced by a mixture of arsenic-cadmium-lead. Oxidative damage and antioxidant response were determined. Metal mixture treatment induces the increase of damage markers and the antioxidant response. Loss of cell viability and increased transforming potential were observed during the promotion phase. This finding correlated significantly with generation of reactive oxygen species. Cotreatment with N-acetyl-cysteine induces effect on the transforming capacity; while a diminution was found in initiation, in promotion phase a total block of the transforming capacity was observed. Our results suggest that oxidative stress generated by metal mixture plays an important role only in promotion phase promoting transforming capacity

Factores de riesgo Materno-Fetales asociados a ruptura prematura de membranas en mujeres con embarazo pretérmino atendidas en el Hospital Victoria Motta de Jinotega de Enero a Diciembre de 2013

El presente trabajo tiene como objetivo fundamental conocer los factores de riesgo tanto maternos como fetales y la relación que guardancon el desarrollo de Ruptura Prematura de Membranas en mujeres con embarazo pretérmino atendidas en el Hospital Victoria Motta de Jinotega en el año 2013.Para ello se realizó un estudio observacional analítico de casos y controles de pacientes ingresadas con embarazos entre las 28 y las 36 6/7 semanas de gestación, en la sala de Alto Riesgo Obstétrico (ARO). El universo estuvo conformado por 323 pacientes con embarazo pretérmino, la muestra se estimó de acuerdo a los criterios de inclusión, siendo el total de casos de 40 que ingresaron con el diagnóstico de Ruptura Prematura de Membranas y los controles de 80 para un total de 120 pacientes en estudio. Entre los resultados se destacan, los factores de riesgo maternos: las mujeres menores de 20 años, procedentes del área rural, con baja escolaridad, sin pareja. Además de la presencia de antecedentes patológicos como las infecciones de vías urinarias (76.9% de los casos), las infecciones vaginales presentesen el 69.2% de los casos. Un 85% de los casos tenían un número de controles prenatales menor de 4 lo que incrementa el riesgo de presentar RPM. Además la presencia de polihidramnios. Se concluyó que los principales factores de riesgo estadísticamente significativos asociados al problema en estudio entre las mujeres fueron: la edad, el bajo nivel educativo, la presencia de infecciones del tracto genitourinario, tener menos de 4 controles prenatales y como factor de riesgo fetal, la presencia de polihidramnios. Priorizar al grupo de mujeres menores de 20 años, procedentes de áreas rurales, con baja escolaridad y con antecedentes de infecciones de vías urinarias y vaginales. Enfatizar la consejería durante el control prenatal sobre los signos de peligro del embarazo

Quantum key distribution based on selective post-processing in passive optical networks

One of the main obstacles to the widespread adoption of quantum cryptography has been the difficulty of integration into standard optical networks, largely due to the tremendous difference in power of classical signals compared with the single quantum used for quantum key distribution. This makes the technology expensive and hard to deploy. In this letter, we show an easy and straightforward integration method of quantum cryptography into optical access networks. In particular, we analyze how a quantum key distribution system can be seamlessly integrated in a standard access network based on the passive optical and time division multiplexing paradigms. The novelty of this proposal is based on the selective post-processing that allows for the distillation of secret keys avoiding the noise produced by other network users. Importantly, the proposal does not require the modification of the quantum or classical hardware specifications neither the use of any synchronization mechanism between the network and quantum cryptography devices