Dye-sensitized Photooxygenation of furanosyl Furans; Synthesis of a new Pyridazine C-Nucleoside

The dye-sensitized photooxygenation of furanosyl furans easily affords C- or O-glycosides with cis-R,-unsaturated 1,4-dioxo aglycones. The reaction, performed on a ribofuranosyl furan, provides a useful new entry to a novel pyridazine C-nucleoside that can be achieved through a simple one-pot procedure

Read Operators and their Expressiveness in Process Algebras

We study two different ways to enhance PAFAS, a process algebra for modelling asynchronous timed concurrent systems, with non-blocking reading actions. We first add reading in the form of a read-action prefix operator. This operator is very flexible, but its somewhat complex semantics requires two types of transition relations. We also present a read-set prefix operator with a simpler semantics, but with syntactic restrictions. We discuss the expressiveness of read prefixes; in particular, we compare them to read-arcs in Petri nets and justify the simple semantics of the second variant by showing that its processes can be translated into processes of the first with timed-bisimilar behaviour. It is still an open problem whether the first algebra is more expressive than the second; we give a number of laws that are interesting in their own right, and can help to find a backward translation.Comment: In Proceedings EXPRESS 2011, arXiv:1108.407

Statistical early-warning indicators based on Auto-Regressive Moving-Average processes

We address the problem of defining early warning indicators of critical transition. To this purpose, we fit the relevant time series through a class of linear models, known as Auto-Regressive Moving-Average (ARMA(p,q)) models. We define two indicators representing the total order and the total persistence of the process, linked, respectively, to the shape and to the characteristic decay time of the autocorrelation function of the process. We successfully test the method to detect transitions in a Langevin model and a 2D Ising model with nearest-neighbour interaction. We then apply the method to complex systems, namely for dynamo thresholds and financial crisis detection.Comment: 5 pages, 4 figure

Probing turbulence intermittency via Auto-Regressive Moving-Average models

We suggest a new approach to probing intermittency corrections to the Kolmogorov law in turbulent flows based on the Auto-Regressive Moving-Average modeling of turbulent time series. We introduce a new index $\Upsilon$ that measures the distance from a Kolmogorov-Obukhov model in the Auto-Regressive Moving-Average models space. Applying our analysis to Particle Image Velocimetry and Laser Doppler Velocimetry measurements in a von K\'arm\'an swirling flow, we show that $\Upsilon$ is proportional to the traditional intermittency correction computed from the structure function. Therefore it provides the same information, using much shorter time series. We conclude that $\Upsilon$ is a suitable index to reconstruct the spatial intermittency of the dissipation in both numerical and experimental turbulent fields.Comment: 5 page

Navigation: How Spatial Cognition Is Transformed into Action

Navigation relies on the brain's ability to build a cognitive map of the environment, and to use such a map to guide the animal's movements to goals. A new study proposes that the secondary motor cortex might convert the map into action

On the presence of the Ponto-Caspian hydrozoan Cordylophora caspia (Pallas, 1771) in an Iberian estuary: highlights on the introduction vectors and invasion routes

Several non-native invertebrate and vertebrate species have been detected in the Guadiana Estuary (SW-Iberian Peninsula, Europe) during the 21st century. In June 2015, the non-native hydroid Cordylophora caspia (Pallas, 1771) was detected for the first time in this estuary, which motivated an assessment of its distribution during late Spring and Summer 2016. The main goals of this paper were to: i) report the presence of Cordylophora caspia and its distribution in the Guadiana Estuary, ii) record the substrates colonized, salinity, and water temperatures at locations where the species was detected, iii) evaluate possible introduction vectors and invasion routes; and iv) discuss the potential impacts and management options. Cordylophora caspia occupied a 25-km stretch of the estuary with salinities between 0.2 and 13.8 and occupied a variety of human-made substrates. Shipping was the most likely introduction vector of C. caspia, which might have originated from populations in the Atlantic Ocean or the Mediterranean Sea. Currently, the potential ecological impacts are likely low since the population size is small due to an apparent shortage of suitable habitat. Economic effects are minimal at present because there are no major industries along the basin extracting water from the estuary. An integrated ecohydrological approach-i.e. freshets released from dams to control the populations of Cnidaria-was proposed to minimize or mitigate the potential negative effects of this species in the Guadiana Estuary.Delta Stewardship Council; Delta Science Program [1167]; Foundation for Science and Technology (FCT, Portugal) through the Jellyfisheries project [PTDC/MAR-BIO/0440/2014]; European Regional Development Fund (COMPETE program-Operational Competitiveness Programme); FCT [SFRH/BPD/108949/2015]; [UID/Multi/04326/2013]info:eu-repo/semantics/publishedVersio

Photochemical behavior of the drug atorvastatin in water.

Atorvastatin undergoes a self-sensitized photooxygenation by sunlight in water. The main photoproducts, isolated by chromatographic techniques, have been identified by spectroscopic means. They present a lactam ring arising from an oxidation of pyrrole ring and an alkyl/aryl shift. A mechanism involving singlet oxygen addition and an epoxide intermediate is suggested

Photooxygenation of furans in water and ionic liquid solutions

Photooxygenation of differently functionalized furans is investigated in aqueous solutions and in ionic liquids [emim]Br and [bmim]BF4. The reaction is generally selective and the final products derive from rearrangement of the intermediate endoperoxides, depending mainly on the polarity and/or nucleophilic nature of the solvent

Spatial mobility and horticulture in te middle valley of Río Negro: the construction of a migratory territory

El presente trabajo tiene como propósito caracterizar al Valle Medio del rio Negro como territorio hortícola y dar cuenta de los procesos de movilidad espacial que permiten considerarlo como un territorio migratorio. Para ello presentaremos la descripción de dos trayectorias de productores de nacionalidad boliviana que se dedican a la producción hortícola en este oasis agrícola/espacio productivo.La región de estudio ha desarrollado en las últimas décadas una considerable expansión de la producción hortícola, concentrando en la actualidad el 48% de la superficie de la provincia destinada a este tipo de producción. El cultivo de tomate para industria, el de cebolla para el mercado interno y para la exportación y, el de verduras para consumo en fresco destinado a mercados regionales y ferias locales son las principales opciones entre las que se dirime la producción.En este dinamismo de la actividad, las familias migrantes, principalmente de origen boliviano, han sido un componente central ya que son ellas las que, en su mayoría, se dedican al cultivo y comercialización de productos hortícolas.En las experiencias de vida de estos migrantes se entrecruzan el “habitus migratorio”, es decir la costumbre de “partir” de sus hogares hacia distintos lugares, y la posibilidad de construir su territorio migratorio. En este sentido, la trayectoria migratoria, laboral y productiva de Lourdes y David que aquí presentamos nos permite aproximarnos al análisis de estos procesos.Este trabajo es abordado desde un enfoque interdisciplinar en el que los aportes de la antropología y la sociología se suman a los de la geografía, y permiten aproximarnos a comprender la complejidad que caracteriza a los procesos migratorios. De esta forma se toman los conceptos de territorio, territorio migratorio, movilidad espacial y trayectorias como ejes que vertebran y enriquecen esta propuesta de abordaje El trabajo se basa en un diseño principalmente cualitativo, en el cual los estudios de caso y los relatos biográficos son piezas clave de la investigación. En este sentido, las observaciones, registros y entrevistas realizadas durante la permanencia en el área de estudio, se combinan con datos secundarios que provienen de la sistematización de censos de población, censos y encuestas agropecuarias y bibliografía específica.This paper aims to characterize the Middle Valley of Río Negro like a horticultural land and show the processes of spatial mobility that allow considered as an migratory territory. This will present the description of two producer’s trajectories Bolivian who work in horticultural production in this productive space. The study area has developed in the last decades a considerable expansion of horticultural production, currently concentrating 48% of the province's surface devoted for this type of production. The cultivation of tomato for industry, onion for the domestic market and for export, and the vegetables for fresh consumption aimed at regional markets and local fairs are the main options in this type of production. In this dynamic activity, migrant families, mainly of Bolivian, have been a central component since they are the ones that mostly involved in the cultivation and marketing of horticultural products. In the life experiences of these migrants the "migratory habitus” intersect, is the habit of "leaves" their homes to different places, and the possibility of building their migratory territory. In this sense, migratory, work and productive trajectories of Lourdes and David presented here allows us to approach the analysis of these processes. This work is addressed from an interdisciplinary approach in which the contributions of anthropology and sociology add to geography, and allow closer to understanding the complexity that characterizes migration. Thus, the concepts of territory, migratory territory, spatial mobility and trajectories are very important elements in the organization or this paper. This work is mainly based on a qualitative design, in which the case studies and biographical accounts are established as key pieces of research. In this sense, observations, records and interviews while within the study area, combined with secondary data coming from the systematization of population censuses, agricultural censuses and surveys and specific bibliography.Fil: Abarzúa, Flavio Daniel. Universidad Nacional del Comahue. Facultad de Humanidades. Departamento de Geografia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Brouchoud, Maria Silvia. Universidad Nacional del Comahue. Facultad de Humanidades. Departamento de Geografia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin