A Generic Communications Module for Cooperative 3D Visualization and Modelling over the Internet: the Collaborative API

Cooperative three-dimensional visualization and modeling applications allow a distributed group of users to work together with a model they share. To implement this kind of applications the underlying communications system must provide reliable and ordered multicast of users interactions. Due to the high complexity that characterizes the models, network bandwidth requirements have limited their use to intranets or in a few cases to very high-speed Internet connections. In this paper we present a communications module that solves this problem. The library exposed, which is called Collaborative API, supports the creation of very efficient cooperative 3D visualization and modeling applications by optimizing the use of the network resources. The Collaborative API, implements a new communications architecture: the dynamic client/server. The communications module presented in this paper is illustrated by two examples of applications that use it to provide cooperative 3D visualization over the Internet

Effects of chronic exposure to the new insecticide sulfoxaflor in combination with a SDHI fungicide in a solitary bee

The recent EU ban of the three most widely used neonicotinoids (imidacloprid, thiamethoxam and clothianidin) to all outdoors applications has stimulated the introduction of new insecticides into the market. Sulfoxaflor is a new systemic insecticide that, like neonicotinoids, acts as a modulator of nicotinic acetylcholine receptors. In agro-environments, bees can be exposed to this compound via contaminated pollen and nectar for long periods of time. Therefore, it is important to assess the potential effects of chronic exposure to sulfoxaflor, alone and in combination with fungicides, on pollinators. In this study, we tested the effects of chronic exposure to two field concentrations of sulfoxaflor (20 and 100 ppb) alone and in combination with four concentrations of the fungicide fluxapyroxad (7500, 15,000, 30,000 and 60,000 ppb) on syrup consumption and longevity in females of the solitary bee Osmia bicornis L. Exposure to 20 ppb of sulfoxaflor, alone and in combination with the fungicide, stimulated syrup consumption, but did not affect longevity. In contrast, syrup consumption decreased in bees exposed to 100 ppb, all of which died after 2–6 days of exposure. We found no evidence of synergism between the two compounds at any of the two sulfoxaflor concentrations tested. Comparison of our findings with the literature, confirms that O. bicornis is more sensitive to sulfoxaflor than honey bees. Our results highlight the need to include different bee species in risk assessment schemes

Variación de la temperatura electrónica en la región E con la actividad magnética

La temperatura Te del gas de electrones en la región E de la ionosfera varía fuertemente con la actividad solar y la magnética. En días geomagnéticamente quietos, la variación con la actividad solar de los perfiles de Te/Tn, siendo T la temperatura del gas neutro, está bien representada por una función de Lorentz. En el presente trabajo se proponen relaciones empíricas que vinculan Te/Tn en días geomagnéticamente no quietos con las actividades solar y magnética para latitudes medias.In the E region of the ionosphere the electron gas temperature, Te, varies strongly with solar and magnetic activities. On geomagnetically quiet days,a Lorentzian function is a good representation of the variation with solar activity of the Te/Tn profiles, where 1 denotes the neutral gas temperature. In the present paper, empirical relation between Te/Tn and magnetic and solar activities on geomagnetically quiet days and middle latitudes are proposed.Asociación Argentina de Geofísicos y Geodesta

La corriente integrada en la capa E ecuatorial: modelo teórico y su aplicación

Recientes cálculos teóricos han predicho una amplificación de la corriente integrada en el ecuador mucho mayor que la observada. En el presente trabajo se calcula dicha corriente y se muestra que un mejor acuerdo entre la observación y la teoría resulta de utilizar para el cálculo de la conductividad eléctrica perfiles de temperatura electrónica medidos in situ, en vez de la hipótesis usual de equilibrio térmico entre electrones y componentes neutros de la atmósfera. Se muestra también la dependencia de esa corriente con la actividad solar.Recent theoretical calculations have predicted an amplification of the integrated current at the equator much greater than the observed value. This current is calculated in^the present work, and it is shown that a better agreement between observation and theory is achieved when electron temperature profiles measured in situ are used for calculating the electrical conductivity, instead of the usual assumption of thermal equilibrium between the electrons and neutral components. The dependence of this current on solar activity is also shown.Asociación Argentina de Geofísicos y Geodesta

Obtención de la temperatura vibracional del N₂ a partir de la densidad del ión de oxígeno atómico

La densidad del 0⁺ depende fuertemente de la densidad del 0 y de la temperatura vibracional del N₂Tv; si esta última fuera suficientemente alta, la transferencia de energía vibracional del N₂ a los electrones térmicos explicaría la alta temperatura de los mismos en la región E de la ionosfera. Por lo tanto, de la densidad de 0⁺ medida se obtiene un perfil de Tv entre los 100 y los 130 km de altura, mediante éste, y en condiciones equivalentes de actividad solar y magnética, se calcula la transferencia de energía entre el N₂ y los electrones térmicos, encontrándose una Tv muy superior a la necesaria para que sea este el mecanismo primario que explique la elevada temperatura a la que los electrones se encuentran. Para este cálculo se seleccionó cuidadosamente la densidad del 0, la cual está, de acuerdo a recientes mediciones, muy por debajo de la prescrlpta por los modelos usuales.The density of the 0⁺ depends strongly on the 0 density and on the N₂ vibrational temperature, Tv; if the last were sufficiently high, the transfer of vibrational energy from N₂ to the thermal electrons might explain the high electron temperatures measured In the E-region. Therefore, from the measured 0+ concentration a Tv profile for the altitude interval between 100 and 130 km Is obtained with which, for equivalent geomagnetic and solar conditions, the rate of change of energy between N₂ and thermal electrons Is calculated. Tv is found to be much higher than required for this to be primary mechanism to explain the high values of the observed electron temperature. For this calculation the 0 density was carefully selected because, according to recent measurements, It Is much lower than the density given by the usual models.Asociación Argentina de Geofísicos y Geodesta

A Political Economy of Privatization Contracts : The Case of Water and Sanitation in Ghana and Argentina

This document is the Accepted Manuscript version of the following article: Hulya Dagdeviren, Simon A. Robertson, 'A Political Economy of Privatization Contracts: The Case of Water and Sanitation in Ghana and Argentina', Competition & Change, Vol. 18 (2): 150-163, April 2014. The final, published version is available online at DOI: https://doi.org/10.1179/1024529414Z.00000000053. Published by SAGE.In general, the process and outcomes of privatization have been studied from the point of view of efficiency. In this article, we consider issues in the course of contract design, implementation, management and enforcement in privatized public services and utilities. The study is based on two case studies, involving several water concessions in Argentina and a management contract in the urban water sector in Ghana. Three key arguments are presented on the basis of these case studies. The first is that an individualistic analytical framework is often utilized by the mainstream economic perspectives, but these are inadequate for a comparative assessment of private versus public provision in public services where there are distinct collective or group interests and hence a wider socio-economic context and representation of different interests becomes highly important. Instead, the article proposes a political economy perspective, which pays due attention to distributional issues, group interests, ideology of states and power relations for the assessment of privatization contracts. Second, the administrative capacity of states and their resources play a key role for the outcomes of privatization. Finally, while some contractual issues could be resolved through resourcing and experience over time, others are inherent to the contractual relations with little prospect of remedy.Peer reviewe

La temperatura electrónica en la región E de la ionosfera

Las mediciones de la temperatura electrónica en la región E hechas con sonda de Langmuir "in situ" y con radar de dispersión de Thomson son contradictorias. En un trabajo anterior de las autoras se encontró evidencia a favor del primer método el cual indica un fuerte desequilibrio térmico entre los electrones y los componentes neutros de la atmósfera. En el presente trabajo, los dos métodos de medición mencionados se discuten, y se encuentran algunos indicios de las causas de las discrepancias entre sus resultados. Se analizan además, los mecanismos del calentamiento anómalo de los electrones propuestos hasta el presente.The measurements of the electron temperature in the E-region "in situ" by the Langmuir probe method and by Thomson scattering,are contradictory. In an earlier work by the authors evidence was shown in favour of the results obtained by the first method, which indicates a strong thermal non-equi1ibrium between the electrons and the neutral atmosphere in that region of the ionosphere. Id the present work, the two methods of measurement are discussed, and indications of the causes for the discrepancy between them are found. The anomalous electron heating mechanisms proposed so far are also analyzed.Asociación Argentina de Geofísicos y Geodesta

Variación de las densidades iónicas con la actividad solar

Para calcular la composición de la región E de la ionósfera para actividad solar alta es usual que se cuadruplique la radiación solar incidente medida de manera que los perfiles electrónicos obtenidos coincidan con los observados, Con el fin de analizar la causa de esta discrepancia en el presente trabajo se resuelve el sistema de ecuaciones de continuidad de los Iones en la reglón E para dos actividades solares, una alta (F₁₀.₇=166) y otra baja (F₁₀.₇=76). Para ello se utilizan perfiles de temperatura y densidad electrónica medidos simultáneamente y espectros de flujo solar observados en condiciones equivalentes. Se encuentra que la discrepancia entre el flujo solar medido y el requerido en los cálculos teóricos se debe a la suposición de equilibrio térmico entre electrones y gas neutro.In order to calculate the composition of the ionospheric E-region, the measured incident solar radiation is usually multiplied by four so that the electron density profiles obtained may agree with the observed profiles. In the present work, in order to analyze the cause of this discrepancy, the system of ionic continuity equations in the E-reglon is solved for two solar activities, one high (F₁₀.₇=166) and the other low (F₁₀.₇=76). For this purpose, simultaneous measurements of temperature and electron density, and solar flux spectra observed under equivalent conditions, are used. The discrepancy between the measured solar flux and the one required In the other theoretical calculations is due to the assumption of thermal equilibrium between the electrons and the neutral gas.Asociación Argentina de Geofísicos y Geodesta

G Protein Subunit Dissociation and Translocation Regulate Cellular Response to Receptor Stimulation

We examined the role of G proteins in modulating the response of living cells to receptor activation. The response of an effector, phospholipase C-β to M3 muscarinic receptor activation was measured using sensors that detect the generation of inositol triphosphate or diacylglycerol. The recently discovered translocation of Gβγ from plasma membrane to endomembranes on receptor activation attenuated this response. A FRET based G protein sensor suggested that in contrast to translocating Gβγ, non-translocating Gβγ subunits do not dissociate from the αq subunit on receptor activation leading to prolonged retention of the heterotrimer state and an accentuated response. M3 receptors with tethered αq induced differential responses to receptor activation in cells with or without an endogenous translocation capable γ subunit. G protein heterotrimer dissociation and βγ translocation are thus unanticipated modulators of the intensity of a cell's response to an extracellular signal

Sharp boundaries of Dpp signalling trigger local cell death required for Drosophila leg morphogenesis

Article available at http://dx.doi.org/10.1038/ncb1518Morphogens are secreted signalling molecules that govern many developmental processes1. In the Drosophila wing disc, the transforming growth factor (TGF) homologue Decapentaplegic (Dpp) forms a smooth gradient and specifies cell fate by conferring a defined value of morphogen activity. Thus, neighbouring cells have similar amounts of Dpp protein, and if a sharp discontinuity in Dpp activity is generated between these cells, Jun kinase (JNK)-dependent apoptosis is triggered to restore graded positional information2, 3. To date, it has been assumed that this apoptotic process is only activated when normal signalling is distorted. However, we now show that a similar process occurs during normal development: rupture in Dpp activity occurs during normal segmentation of the distal legs of Drosophila. This sharp boundary of Dpp signalling, independently of the absolute level of Dpp activity, induces a JNK—reaper-dependent apoptosis required for the morphogenesis of a particular structure of the leg, the joint. Our results show that Dpp could induce a developmental programme not only in a concentration dependent manner, but also by the creation of a sharp boundary of Dpp activity. Furthermore, the same process could be used either to restore a normal pattern in response to artificial disturbance or to direct a morphogenetic process.This work has been supported by grants from the Dirección General de Investigación Científica y Técnica (BMC 2002-00300), the Comunidad Autónoma de Madrid (08.1/0031/2001.1 and GR/SAL/0147/2004) and an Institutional Grant from the Fundación Ramón Areces. C.M. is a recipient of a Formación del Personal Universitario (F.P.U.) fellowship from the Ministerio de Educación y Ciencia.Peer reviewe