Selective Transport of Zinc, Manganese, Nickel, Cobalt and Cadmium in the Root System and Transfer to the Leaves in Young Wheat Plants

• Background and Aims The uptake, translocation and redistribution of the heavy metals zinc, manganese, nickel, cobalt and cadmium are relevant for plant nutrition as well as for the quality of harvested plant products. The long-distance transport of these heavy metals within the root system and the release to the shoot in young wheat (Triticum aestivum ‘Arina’) plants were investigated. • Methods After the application of 65Zn, 54Mn, 63Ni, 57Co and 109Cd for 24 h to one seminal root (the other seminal roots being excised) of 54-h-old wheat seedlings, the labelled plants were incubated for several days in hydroponic culture on a medium without radionuclides. • Key Results The content of 65Zn decreased quickly in the labelled part of the root. After the transfer of 65Zn from the roots to the shoot, a further redistribution in the phloem from older to younger leaves was observed. In contrast to 65Zn, 109Cd was released more slowly from the roots to the leaves and was subsequently redistributed in the phloem to the youngest leaves only at trace levels. The content of 63Ni decreased quickly in the labelled part of the root, moving to the newly formed parts of the root system and also accumulating transiently in the expanding leaves. The 54Mn content decreased quickly in the labelled part of the root and increased simultaneously in leaf 1. A strong retention in the labelled part of the root was observed after supplying 57Co. • Conclusions The dynamics of redistribution of 65Zn, 54Mn, 63Ni, 57Co and 109Cd differed considerably. The rapid redistribution of 63Ni from older to younger leaves throughout the experiment indicated a high mobility in the phloem, while 54Mn was mobile only in the xylem and 57Co was retained in the labelled root without being loaded into the xylem.

A new measure for party coherence: Applying a physics-based concept to the Swiss party system

The paper revives a theoretical definition of party coherence as being composed of two basic elements, cohesion and factionalism, to propose and apply a novel empirical measure based on spin physics. The simultaneous analysis of both components using a single measurement concept is applied to data representing the political beliefs of candidates in the Swiss general elections of 2003 and 2007, proposing a connection between the coherence of the beliefs party members hold and the assessment of parties being at risk of splitting. We also compare our measure with established polarization measures and demonstrate its advantage with respect to multi-dimensional data that lack clear structure. Furthermore, we outline how our analysis supports the distinction between bottom-up and top-down mechanisms of party splitting. In this way, we are able to turn the intuition of coherence into a defined quantitative concept that, additionally, offers a methodological basis for comparative research of party coherence. Our work serves as an example of how a complex systems approach allows to get a new perspective on a long-standing issue in political science.

Global distributions of pteropods (Gymnosomata, Thecosomata, Pseudothecosomata) abundance and biomass - Gridded data product (NetCDF) - Contribution to the MAREDAT World Ocean Atlas of Plankton Functional Types

Pteropods are a group of holoplanktonic gastropods for which global biomass distribution patterns remain poorly resolved. The aim of this study was to collect and synthesize existing pteropod (Gymnosomata, Thecosomata and Pseudothecosomata) abundance and biomass data, in order to evaluate the global distribution of pteropod carbon biomass, with a particular emphasis on its seasonal, temporal and vertical patterns. We collected 25 902 data points from several online databases and a number of scientific articles. The biomass data has been gridded onto a 360 x 180° grid, with a vertical resolution of 33 WOA depth levels. Data has been converted to NetCDF format. Data were collected between 1951-2010, with sampling depths ranging from 0-1000 m. Pteropod biomass data was either extracted directly or derived through converting abundance to biomass with pteropod specific length to weight conversions. In the Northern Hemisphere (NH) the data were distributed evenly throughout the year, whereas sampling in the Southern Hemisphere was biased towards the austral summer months. 86% of all biomass values were located in the NH, most (42%) within the latitudinal band of 30-50° N. The range of global biomass values spanned over three orders of magnitude, with a mean and median biomass concentration of 8.2 mg C l-1 (SD = 61.4) and 0.25 mg C l-1, respectively for all data points, and with a mean of 9.1 mg C l-1 (SD = 64.8) and a median of 0.25 mg C l-1 for non-zero biomass values. The highest mean and median biomass concentrations were located in the NH between 40-50° S (mean biomass: 68.8 mg C l-1 (SD = 213.4) median biomass: 2.5 mg C l-1) while, in the SH, they were within the 70-80° S latitudinal band (mean: 10.5 mg C l-1 (SD = 38.8) and median: 0.2 mg C l-1). Biomass values were lowest in the equatorial regions. A broad range of biomass concentrations was observed at all depths, with the biomass peak located in the surface layer (0-25 m) and values generally decreasing with depth. However, biomass peaks were located at different depths in different ocean basins: 0-25 m depth in the N Atlantic, 50-100 m in the Pacific, 100-200 m in the Arctic, 200-500 m in the Brazilian region and >500 m in the Indo-Pacific region. Biomass in the NH was relatively invariant over the seasonal cycle, but more seasonally variable in the SH. The collected database provides a valuable tool for modellers for the study of ecosystem processes and global biogeochemical cycles.

Accumulation, velocities, fluxes and mass balance of glacial tributaries to the Lambert Glacier-Amery Ice Shelf system, Antarctica

By incorporating recently available remote sensing data, we investigated the mass balance for all individual tributary glacial basins of the Lambert Glacier-Amery Ice Shelf system, East Antarctica. On the basis of the ice flow information derived from SAR interferometry and ICESat laser altimetry, we have determined the spatial configuration of eight tributary drainage basins of the Lambert-Amery glacial system. By combining the coherence information from SAR interferometry and the texture information from SAR and MODIS images, we have interpreted and refined the grounding line position. We calculated ice volume flux of each tributary glacial basin based on the ice velocity field derived from Radarsat three-pass interferometry together with ice thickness data interpolated from Australian and Russian airborne radio echo sounding (RES) surveys and inferred from ICESat laser altimetry data. Our analysis reveals that three tributary basins have a significant net positive imbalance, while five other subbasins are slightly positive or close to zero balance. Overall, in contrast to previous studies, we find that the grounded ice in Lambert Glacier-Amery Ice Shelf system has a positive mass imbalance of 22.9 ± 4.4 Gt/a. The net basal melting for the entire Amery Ice Shelf is estimated to be 27.0 ± 7.0 Gt/a. The melting rate decreases rapidly from the grounding zone to the ice shelf front. Significant basal refreezing is detected in the downstream section of the ice shelf. The mass balance estimates for both the grounded ice sheet and the ice shelf mass differ substantially from other recent estimates.

Properties of seawater (pH total scale) from a Satlantic SeaFET instrument mounted on the continuous surface water sampling system during the Tara Oceans expedition 2009-2013

The Tara Oceans Expedition (2009-2013) sampled the world oceans on board a 36 m long schooner, collecting environmental data and organisms from viruses to planktonic metazoans for later analyses using modern sequencing and state-of-the-art imaging technologies. Tara Oceans Data are particularly suited to study the genetic, morphological and functional diversity of plankton. The present data set provides continuous pH measurements made during 2013 expedition with a Satlantic SeaFET instrument that was connected to the flowthrough system. Data calibration was performed according to Bresnahan et al. (2014) (using spectrophotometric pH measurements on discrete samples (Clayton and Byrne 1993). pH_internal values were taken to calibrate the data (rather than pH_external) because of the better calibration coefficient (there was no trend associated with it). The equations of Clayton and Byrne (1993) was used to compute pH from the measured absorbance values at the temperature of measurement. The data was converted to in situ temperature using the "CO2-sys" program which can be downloaded from http://cdiac.ornl.gov/ftp/co2sys/.

Using Clouds to Scale Grid Resources: An Economic Model

Infrastructure as a Service clouds are a flexible and fast way to obtain (virtual) resources as demand varies. Grids, on the other hand, are middleware platforms able to combine resources from different administrative domains for task execution. Clouds can be used by grids as providers of devices such as virtual machines, so they only use the resources they need. But this requires grids to be able to decide when to allocate and release those resources. Here we introduce and analyze by simulations an economic mechanism (a) to set resource prices and (b) resolve when to scale resources depending on the users’ demand. This system has a strong emphasis on fairness, so no user hinders the execution of other users’ tasks by getting too many resources. Our simulator is based on the well-known GridSim software for grid simulation, which we expand to simulate infrastructure clouds. The results show how the proposed system can successfully adapt the amount of allocated resources to the demand, while at the same time ensuring that resources are fairly shared among users.

Single-Stage Grid-Connected Forward Microinverter with Boundary Mode Control

This paper presents a microinverter to be integrated into a solar module. The proposed solution combines a forward converter and a constant off-time boundary mode control, providing MPPT capability and unity power factor in a single-stage converter. The transformer structure of the power stage remains as in the classical DC-DC forward converter. Transformer primary windings are utilized for power transfer or demagnetization depending on the grid semi-cycle. Furthermore, bidirectional switches are used on the secondary side allowing direct connection of the inverter to the grid. Design considerations for the proposed solution are provided, regarding the inductance value, transformer turns ratio and frequency variation during a line semi-cycle. The decoupling of the twice the line frequency power pulsation is also discussed, as well as the maximum power point tracking (MPPT) capability. Simulation and experimental results for a 100W prototype are enclosed

Fiabilidad de los sistemas fotovoltaicos autónomos

Los sistemas fotovoltaicos autónomos, es decir, sistemas que carecen de conexión a la red eléctrica, presentan una gran utilidad para poder llevar a cabo la electrificación de lugares remotos donde no hay medios de acceder a la energía eléctrica. El continuo avance en el número de sistemas instalados por todo el mundo y su continua difusión técnica no significa que la implantación de estas instalaciones no presente ninguna problemática. A excepción del panel fotovoltaico que presenta una elevada fiabilidad, el resto de elementos que forman el sistema presentan numerosos problemas y dependencias, por tanto el estudio de las fiabilidades de estos elementos es obligado. En este proyecto se pretende analizar y estudiar detalladamente la fiabilidad de los sistemas fotovoltaicos aislados. Primeramente, el presente documento ofrece una introducción sobre la situación mundial de las energías renovables, así como una explicación detallada de la energía fotovoltaica. Esto incluye una explicación técnica de los diferentes elementos que forman el sistema energético (módulo fotovoltaico, batería, regulador de carga, inversor, cargas, cableado y conectores). Por otro lado, se hará un estudio teórico del concepto de fiabilidad, con sus definiciones y parámetros más importantes. Llegados a este punto, el proyecto aplica la teoría de fiabilidad comentada a los sistemas fotovoltaicos autónomos, profundizando en la fiabilidad de cada elemento del sistema así como evaluando el conjunto. Por último, se muestran datos reales de fiabilidad de programas de electrificación, demostrando la variedad de resultados sujetos a los distintos emplazamientos de las instalaciones y por tanto distintas condiciones de trabajo. Se destaca de esta forma la importancia de la fiabilidad de los sistemas fotovoltaicos autónomos, pues normalmente este tipo de instalaciones se localizan en emplazamientos remotos, sin personal cualificado de mantenimiento cercano ni grandes recursos logísticos y económicos. También se resalta en el trabajo la dependencia de la radiación solar y el perfil de consumo a la hora de dimensionar el sistema. Abstract Stand-alone photovoltaic systems which are not connected to the utility grid. These systems are very useful to carry out the electrification of remote locations where is no easy to access to electricity. The number increased of systems installed worldwide and their continued dissemination technique does not mean that these systems doesn´t fails. With the exception of the photovoltaic panel with a high reliability, the remaining elements of the system can to have some problems and therefore the study of the reliabilities of these elements is required. This project tries to analyze and study the detaila of the reliability of standalone PV systems. On the one hand, this paper provides an overview of the global situation of renewable energy, as well as a detailed explanation of photovoltaics. This includes a technical detail of the different elements of the energy system (PV module, battery, charge controller, inverter, loads, wiring and connectors). In addition, there will be a theoricall study of the concept of reliability, with the most important definitions and key parameters. On the other hand, the project applies the reliability concepts discussed to the stand-alone photovoltaic systems, analyzing the reliability of each element of the system and analyzing the entire system. Finally, this document shows the most important data about reliability of some electrification programs, checking the variety of results subject to different places and different conditions. As a conclussion, the importance of reliability of stand-alone photovoltaic systems because usually these are located in remote locations, without qualified maintenance and financial resources.These systems operate under dependence of solar radiation and the consumption profile.

A first approach to the optimization of Bogotá's TransMilenio BRT system

Bus rapid transit (BRT) systems are massive transport systems with medium/high capacity, high quality service and low infrastructure and operating costs. TransMilenio is Bogotá's most important mass transportation system and one of the biggest BRT systems in the world, although it only has completed its third construction phase out of a total of eight. In this paper we review the proposals in the literature to optimize BRT system operation, with a special emphasis on TransMilenio, and propose a mathematical model that adapts elements of the above proposals and incorporates novel elements accounting for the features of TransMilenio system.

Electricity production usíng different photovoltaic technologies working at the same conditíons , a real case

The manufacture of photovoltaic (PV) modules has greatly increased in the past few years. The classical PV module is based on crystalline silicon (e-Si) , nevertheless the so called thinfilm technology is gaining importance each year. In this research paper we present a experimental grid-connected solar plant situated in one of the buildings of the Technical University of Madrid, with two main objectives.

Application of Public Private Partnerships to the Spanish Airport System

The current deficit situation of the Spanish airport system suggests the need to manage this in a more efficient and profitable way. One of the possible options is through private management and being able to do this through Public Private Partnerships (PPP). This study analyzes the situation of the sector and its economic importance and the different possibilities for introducing private management in a public company, specifying the situation in the case of airports, presenting the advantages and disadvantages of these possibilities, and aiming at results obtained in other places where it has been applied. It is proposed that the ideal model for the introduction of private management would be through PPP models tailored to each airport, but having common characteristics according to the group they belong to. Finally, we observe that not all airports are commercially attractive, so that the PPP concept does not apply to all of them. In some cases even the operability itself is not viable at all, and that should be considered separately in order to avoid creating a private monopoly while trying to enhance competition among them.

On the analytical approach for modeling photovoltaic systems behavior

The 1-diode/2-resistors electric circuit equivalent to a photovoltaic system is analyzed. The equations at particular points of the I–V curve are studied considering the maximum number of terms. The maximum power point as a boundary condition is given special attention. A new analytical method is developed based on a reduced amount of information, consisting in the normal manufacturer data. Results indicate that this new method is faster than numerical methods and has similar (or better) accuracy than other existing methods, numerical or analytical.

Hidrogeología e hidrodinámica del acuífero de los manantiales de Gormaz y su importancia en el caudal base del río Duero, España = Hydrogeology and hydrodynamic of the Gormaz Springs Aquifer and its importance to the base flow of the Duero River, Spain

Se cuantifican las descargas subterráneas de un acuífero a un río que lo atraviesa utilizando correlaciones estadísticas. El río Duero, España, incrementa su caudal base en varios m3/s, al atravesar unos afloramientos carbonatados mesozoicos en un pequeño tramo de su cabecera; esto es de especial importancia en época de estiaje, cuando la mayor parte del caudal base del río procede de manantiales que allí se sitúan. Dichos afloramientos corresponden a uno de los dos acuíferos calcáreos confinados, que se desarrollan en paralelo y están hidráulicamente desconectados por una capa impermeable, que forman el sistema acuífero de los manantiales de Gormaz. Este sistema se encuentra en estado de régimen natural y está apenas explotado. Se define el modelo conceptual de funcionamiento hidrogeológico, considerando el papel hidrogeológico de la falla de Gormaz, situada en la zona de descarga del sistema. Analizando información geológica antecedente y la geofísica exploratoria realizada, se obtuvo un mejor conocimiento de la geometría y los límites de los acuíferos, definiéndose un sistema acuífero con una zona de recarga en el sur, correspondiente a los afloramientos calcáreos, los cuales se confinan hacia el norte bajo el Terciario, hasta intersecar con la falla normal de Gormaz. El salto de falla genera una barrera para las formaciones permeables situadas al extremo norte (margen derecha del río Duero); a su vez, el plano de falla facilita el ascenso del agua subterránea del sistema acuífero en estudio y pone en conexión hidráulica los dos acuíferos. Se estimaron, además, los parámetros hidráulicos de los acuíferos en los alrededores de la falla. La buena correlación entre los niveles piezométricos y las descargas subterráneas al río Duero han permitido la reconstrucción del hidrograma de los manantiales de Gormaz en el periodo 1992-2006. Se calcula así que la contribución subterránea al río Duero es de 135.9 hm3/año, que supone el 18.9% de la aportación total del río. In a short stretch of its headwaters, the base flow of the River Duero increases by several m3/s as it traverses some Mesozoic carbonate outcrops. This is of special importance during the dry season, when the majority of the base flow of the river proceeds from springs in this reach. The outcrops correspond to one of two confined calcareous aquifers that developed in parallel but which are not hydraulically connected because of an impermeable layer. Together, they constitute the aquifer system of the Gormaz Springs. The system is still in its natural regime and is hardly exploited. This study defines the conceptual model of hydrogeological functioning, taking into consideration the role of the Gormaz Fault, which is situated in the discharge zone of the system. Analysis of both antecedent geological information and geophysical explorations has led to a better understanding of the geometry and boundaries of the aquifers, defining an aquifer system with a recharge zone in the south corresponding to in the calcareous outcrops. These calcareous outcrops are confined to the north below Tertiary formations, as far as their intersection with the normal fault of Gormaz. The throw of the fault forms the barrier of the permeable formations situated in the extreme north (right bank of the River Duero). In turn, the fault plane facilitates the upflow of groundwater from the aquifer system and creates hydraulic connection between the two aquifers. In addition, the study estimated the hydraulic parameters of the aquifer around the fault. The close correlation between piezometric levels and the groundwater discharges to the River Duero has enabled the reconstruction of the hydrogram of Gormaz springs over the period 1992-2006. By this means, it is calculated that the groundwater contribution to the River Duero is 135.9 hm3/year, or 18.9% of the total river inflow.