183 research outputs found

    Nitrogen in current European policies

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    Europe, and especially the European Union (EU), has many governmental policy measures aimed at decreasing unwanted reactive nitrogen (N_r) emissions from combustion, agriculture and urban wastes. Many of these policy measures have an "effects-based approach", and focus on single N_r compounds, single sectors and either on air or waters. This chapter addresses the origin, objectives and targets of EU policy measures related to N_r emissions, considers which instruments are being used to implement the policies and briefly discusses the effects of the policy measures

    Carbonaceous aerosols in Norwegian urban areas

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    Little is known regarding levels and source strength of carbonaceous aerosols in Scandinavia. In the present study, ambient aerosol (PM<sub>10</sub> and PM<sub>2.5</sub>) concentrations of elemental carbon (EC), organic carbon (OC), water-insoluble organic carbon (WINSOC), and water-soluble organic carbon (WSOC) are reported for a curbside site, an urban background site, and a suburban site in Norway in order to investigate their spatial and seasonal variations. Aerosol filter samples were collected using tandem filter sampling to correct for the positive sampling artefact introduced by volatile and semivolatile OC. Analyses were performed using the thermal optical transmission (TOT) instrument from Sunset Lab Inc., which corrects for charring during analysis. Finally, we estimated the relative contribution of OC from wood burning based on the samples content of levoglucosan. <br><br> Levels of EC varied by more than one order of magnitude between sites, likely due to the higher impact of vehicular traffic at the curbside and the urban background sites. In winter, the level of particulate organic carbon (OC<sub><i>p</i></sub>) at the suburban site was equal to (for PM<sub>10</sub>) or even higher (for PM<sub>2.5</sub>) than the levels observed at the curbside and the urban background sites. This finding was attributed to the impact of residential wood burning at the suburban site in winter, which was confirmed by a high mean concentration of levoglucosan (407 ng m<sup>−3</sup>). This finding indicates that exposure to primary combustion derived OC<sub><i>p</i></sub> could be equally high in residential areas as in a city center. It is demonstrated that OC<sub><i>p</i></sub> from wood burning (OC<sub>wood</sub>) accounted for almost all OC<sub><i>p</i></sub> at the suburban site in winter, allowing a new estimate of the ratio TC<sub><i>p</i></sub>/levoglucosan for both PM<sub>10</sub> and PM<sub>2.5</sub>. Particulate carbonaceous material (PCM=Organic matter+Elemental matter) accounted for 46–83% of PM<sub>10</sub> at the sites studied, thus being the major fraction

    Stability and Representation Dependence of the Quantum Skyrmion

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    A constructive realization of Skyrme's conjecture that an effective pion mass ``may arise as a self consistent quantal effect'' based on an ab initio quantum treatment of the Skyrme model is presented. In this quantum mechanical Skyrme model the spectrum of states with I=JI=J, which appears in the collective quantization, terminates without any infinite tower of unphysical states. The termination point depends on the model parameters and the dimension of the SU(2) representation. Representations, in which the nucleon and Δ33\Delta_{33} resonance are the only stable states, exist. The model is developed for both irreducible and reducible representations of general dimension. States with spin larger than 1/2 are shown to be deformed. The representation dependence of the baryon observables is illustrated numerically.Comment: 19 pages, Late

    Photochemical modelling in the Po basin with focus on formaldehyde and ozone

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    As part of the EU project FORMAT ( Formaldehyde as a Tracer of Oxidation in the Troposphere), a field campaign was carried out in the vicinity of Milan during the summer of 2002. Results from a 3-D regional chemical transport model (NILU RCTM) were used to interpret the observations focusing primarily on HCHO and ozone. The performance of the model was assessed by comparing model results with ground based and aircraft measurements. The model results show good agreement with surface measurements, and the model is able to reproduce the photochemical episodes during fair weather days. The comparison indicates that the model can represent well the HCHO concentrations as well as their temporal and spatial variability. The relationship between HCHO and (O-3 x H2O) was used to validate the model ability to predict the HCHO concentrations. Further analysis revealed the importance of the representativeness of different instruments: in-situ concentrations might be locally enhanced by emissions, while long path measurements over a forest can be influenced by rapid formation of HCHO from isoprene. The model is able to capture the plume from the city of Milan and the modelled levels agree generally well with the aircraft measurements, although the wind fields used in the model can lead to a displacement of the ozone plume. During the campaign period, O3 levels were seldom higher than 80 ppb, the peak surface ozone maxima reached 90 ppb. Those relatively low values can be explained by low emissions during the August vacation and unstable weather conditions in this period. The modelled Delta O-3/Delta NOz slope at Alzate of 5.1 agrees well with the measured slope of 4.9

    La pobreza del Estado : reconsideración del rol del Estado en la lucha contra la pobreza global

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    El espectro de la pobreza ha tenido una presencia constante en la historia de la humanidad. Actualmente es posible erradicar la pobreza extrema. Existen los recursos para lograrlo en un período razonable. Los deseos y la disposición de las organizaciones internacionales, los gobiernos y los pueblos son evidentes en los discursos dominantes que expresan la necesidad y la voluntad de la comunidad internacional de reducir y erradicar la pobreza. ¿Cuáles son los factores que están impidiendo el logro de una meta tan ampliamente aceptada? Es difícil dar una respuesta exhaustiva y precisa a esta pregunta. No obstante, una parte sustancial de la explicación puede estar en una de las estructuras más importantes, pero problemáticas, del mundo moderno, a saber, el Estado.Prefacio / Hartley Dean, Alberto Cimadamore y Jorge Siqueira Introducción Parte I. Dimensiones teórica y global El programa mundial de derechos humanos y la (im)posibilidad del Estado ético Hartley Dean La redefinición del problema social y la retórica acerca de la pobreza durante el decenio de 1990 Anete Brito Leal Ivo La antiglobalización y el antiestatismo desde la perspectiva del postdesarrollo y el antiutilitarismo Paulo Henrique Martins Parte II. Dimensiones política y nacional La estrategia de reducción de la pobreza y la brecha educacional en la Guatemala de posguerra Virgilio Álvarez Aragón El futuro que no llegará: la erradicación de la pobreza desde la perspectiva del gobierno federal de México (2000-2006) Nelson Arteaga Botello Las dificultades de una política de seguridad alimentaria en el Brasil José Graziano da Silva, Walter Belik y Maya Takagi Políticas de empleo público como instrumentos para la reducción de la pobreza y la desigualdad en el Brasil Tarcisio Patricio de Araujo y Roberto Alves de Lima Pobreza, desigualdad y desarrollo: el rol del Estado en la experiencia de Cuba Mayra Paula Espina Prieto ¿Privatización para la reducción de la pobreza? : El caso de Bangladesh y su importancia para otras economías en desarrollo Hulya Dagdeviren Parte III. Dimensiones práctica y local Sinergias frágiles para el desarrollo: el caso de Jardim Oratório, São Paulo, Brasil Rowan Ireland Pobreza, políticas y prestidigitación en Bolivia y América Latina John-Andrew McNeish Fondos Sociales en África: ¿una respuesta clientelístico-tecnocrática a la pobreza? Einar Braathe

    Intercomparison of four different in-situ techniques for ambient formaldehyde measurements in urban air

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    International audienceResults from an intercomparison of several currently used in-situ techniques for the measurement of atmospheric formaldehyde (CH2O) are presented. The measurements were carried out at Bresso, an urban site in the periphery of Milan (Italy) as part of the FORMAT-I field campaign. Eight instruments were employed by six independent research groups using four different techniques: Differential Optical Absorption Spectroscopy (DOAS), Fourier Transform Infra Red (FTIR) interferometry, the fluorimetric Hantzsch reaction technique (five instruments) and a chromatographic technique employing C18-DNPH-cartridges (2,4-dinitrophenylhydrazine). White type multi-reflection systems were employed for the optical techniques in order to avoid spatial CH2O gradients and ensure the sampling of nearly the same air mass by all instruments. Between 23 and 31 July 2002, up to 13 ppbv of CH2O were observed. The concentrations lay well above the detection limits of all instruments. The formaldehyde concentrations determined with DOAS, FTIR and the Hantzsch instruments were found to agree within ±11%, with the exception of one Hantzsch instrument, which gave systematically higher values. The two hour integrated samples by DNPH yielded up to 25% lower concentrations than the data of the continuously measuring instruments averaged over the same time period. The consistency between the DOAS and the Hantzsch method was better than during previous intercomparisons in ambient air with slopes of the regression line not significantly differing from one. The differences between the individual Hantzsch instruments could be attributed in part to the calibration standards used. Possible systematic errors of the methods are discussed

    The record large 2006 Antarctic ozone hole

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    Póster presentado en: EGU General Assembly 2007 celebrada del 15 al 20 de abril en Viena, Austria.The Antarctic ozone hole of 2006 was unusually large. Several parameters used to measure the extent of ozone destruction and ozone hole severity set new records in 2006. Several ground-based stations measured record low total ozone column amounts. Ozonesonde measurements also revealed in many cases record low values of ozone in certain height intervals. The dynamics of the 2006 ozone hole will be described together with satellite-based measurements and calculations of ozone hole area and mass deficit. These finding will be supplemented with several examples of data from various stations in Antarctica

    Two novel missense mutations in the myelin protein zero gene causes Charcot-Marie-Tooth type 2 and Déjérine-Sottas syndrome

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    <p>Abstract</p> <p>Background</p> <p>The Charcot-Marie-Tooth (CMT) phenotype caused by mutation in the <it>myelin protein zero (MPZ) </it>gene varies considerably, from early onset and severe forms to late onset and milder forms. The mechanism is not well understood. The myelin protein zero (P<sub>0</sub>) mediates adhesion in the spiral wraps of the Schwann cell's myelin sheath. The crystalline structure of the extracellular domain of the myelin protein zero (P<sub>0</sub>ex) is known, while the transmembrane and intracellular structure is unknown.</p> <p>Findings</p> <p>One novel missense mutation caused a milder late onset CMT type 2, while the second missense mutation caused a severe early onset phenotype compatible with Déjérine-Sottas syndrome.</p> <p>Conclusions</p> <p>The phenotypic variation caused by different missense mutations in the <it>MPZ </it>gene is likely caused by different conformational changes of the MPZ protein which affects the functional tetramers. Severe changes of the MPZ protein cause dysfunctional tetramers and predominantly uncompacted myelin, i.e. the severe phenotypes congenital hypomyelinating neuropathy and Déjérine-Sottas syndrome, while milder changes cause the phenotypes CMT type 1 and 2.</p

    Observations of the Antarctic ozone hole from 2003-2010

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    Póster presentado en: EGU General Assembly 2011 celebrada del 3 al 8 de abril en Viena, Austria.The Global Atmosphere Watch of WMO includes several stations in Antarctica that keep a close eye on the ozone layer during the ozone hole season. Observations made during the ozone holes from 2003 to 2010 will be compared to each other and interpreted in light of the meteorological conditions. Satellite observations will be used to get a more general picture of the size and depth of the ozone hole and will also be used to calculate various metrics for ozone hole severity. In 2003, 2005 and 2006, the ozone hole was relatively large with more ozone loss than normal. This is in particular the case for 2006, which by most ozone hole metrics was the most severe ozone holeon record. On the other hand, the ozone holes of 2004, 2007 and 2010 were less severe than normal, and only the very special ozone hole of 2002 had less ozone depletion when one regards the ozone holes of the last decade. The interannual variability will be discussed with the help of meteorological data, such as temperature conditions, possibility for polar stratospheric clouds, vortex shape and vortex longevity. Observations will also be compared to 3-D chemical transport model calculations

    The state of the Martian climate

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    60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes
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