WorldWideScience

Sample records for aerosol anthropogenique par

  1. Numerical simulation of the aerosols capture by an array of drops with steam condensation on their surface; Simulation numerique de la collecte des aerosols par une serie de gouttes en presence de condensation a leur surface

    Energy Technology Data Exchange (ETDEWEB)

    Gauchet, N.; Vendel, J. [CEA/Saclay, Inst. de Protection et de Surete Nucleaire, IPSN/DPEA/SERAC, 91 - Gif-sur-Yvette (France); Renoux, A. [Paris-12 Univ., Lab. de Physique des Aerosols et de Transfert des Contaminations, 94 - Creteil (France)

    2000-07-01

    A numerical simulation of aerosol capture by an array of drops with steam condensation on their surface is presented. Particle impaction has been predicted with an Eulerian approach. This work performs the influence of condensation on the aerosol collection efficiency and the evolution of the collection efficiency with the distance between the drops. While varying the distance between the drops from 5 to 25 drop diameters, we can highlight the modification of the impaction collection efficiency related to the disturbance of the velocity and concentration fields in the vicinity of the drops. We observe strong variations of the collection efficiency, but the steam condensation at the surface of the drops limits the decrease. (authors)

  2. Liquid aerosol filtration by fibrous filters in interception and inertial regimes; Filtration des aerosols liquides par les filtres a fibres en regimes d`interception et d`inertie

    Energy Technology Data Exchange (ETDEWEB)

    Gougeon, R.

    1994-09-26

    In most previous studies of aerosol filtration, attention is focused on the maximum penetrating particle size region where the predominant mechanisms for collection are brownian diffusion and interception. In contrary the inertial regime remains poorly understood. Therefore, the aim of this study was to improve understanding of the behaviour of fibrous filters with liquid aerosols ar high frontal velocities both in the stationary and nonstationary filtration. Stationary filtration is first investigated. Experiments are done with special filters called `formettes` which have well defined structural characteristics. Precise results obtained with those filters allow us to select two relations quoted in the literature in order to describe the diffusion and the interception and to determine an empirical correlation describing the inertial impaction. Then this correlation with an industrial filter. In the second part, the evolution of the performances of fibrous filters loaded with liquid aerosols is studied experimentally and theoretically. We show that, in the inertial regime the filter efficiency first decreases and then increases rapidly with the loading rate. This increase is particularly important at high frontal velocities and with big particles. Macroscopic observations of high loaded filters show that the liquid is located in the fibre`s intersections to form big flat surfaces. A tentative of describing the evolution of the filter efficiency in modifying our stationary filtration model in order to take into account those liquid surfaces in the filter gives encouraging results. (authors). 92 refs., 93 figs., 11 tabs., 4 appends.

  3. Par Pond water balance

    International Nuclear Information System (INIS)

    A water budget for the Par Pond hydrologic system was established in order to estimate the rate of groundwater influx to Par Pond. This estimate will be used in modeling exercises to predict Par Pond reservoir elevation and spillway discharge in the scenario where Savannah River water is no longer pumped and discharged into Par Pond. The principal of conservation of mass was used to develop the water budget, where water inflow was set equal to water outflow. Components of the water budget were identified, and the flux associated with each was determined. The water budget was considered balanced when inflow and outflow summed to zero. The results of this study suggest that Par Pond gains water from the groundwater system in the upper reaches of the reservoir, but looses water to the groundwater system near the dam. The rate of flux of groundwater from the water table aquifer into Par Pond was determined to be 13 cfs. The rate of flux from Par Pond to the water table aquifer near the dam was determined to be 7 cfs

  4. Organic aerosols

    International Nuclear Information System (INIS)

    Organic aerosols scatter solar radiation. They may also either enhance or decrease concentrations of cloud condensation nuclei. This paper summarizes observed concentrations of aerosols in remote continental and marine locations and provides estimates for the sources of organic aerosol matter. The anthropogenic sources of organic aerosols may be as large as the anthropogenic sources of sulfate aerosols, implying a similar magnitude of direct forcing of climate. The source estimates are highly uncertain and subject to revision in the future. A slow secondary source of organic aerosols of unknown origin may contribute to the observed oceanic concentrations. The role of organic aerosols acting as cloud condensation nuclei (CCN) is described and it is concluded that they may either enhance or decrease the ability of anthropogenic sulfate aerosols to act as CCN

  5. Marine aerosols

    OpenAIRE

    Saltzman, Es

    2009-01-01

    The aerosol over the world oceans plays an important role in determining the physical and chemical characteristics of the Earth's atmosphere and its interactions with the climate system. The oceans contribute to the aerosols in the overlying atmosphere by the production and emission of aerosol particles and precursor gases. The marine aerosol, in turn, influences the biogeochemistry of the surface ocean through long distance transport and deposition of terrestrial and marine-derived nutrients...

  6. It's quicker "Par Avignon"!

    CERN Multimedia

    2005-01-01

    For a few years, the CERN Library has been receiving books from the University of Hanover sent via Avignon, at least that's what it says on the envelope. Such a detour would mean that parcels were travelling 720 km more than the distance separating Geneva and Hanover, which would be a very strange state of affairs. The explanation lies in a spelling mistake. The sender has been stamping parcels with a stamp that says "Par Avignon prioritaire" (first-class via Avignon) instead of "Par Avion prioritaire" (First Class Air Mail), a source of much amusement to the librarians!

  7. Aerosol studies

    International Nuclear Information System (INIS)

    As part of the continuing studies of the effects of very severe reactor accidents, an effort was made to develop, test, and improve simple, effective, and inexpensive methods by which the average citizen, using only materials readily available, could protect his residence, himself, and his family from injury by toxic aerosols. The methods for protection against radioactive aerosols should be equally effective against a clandestine biological attack by terrorists. The results of the tests to date are limited to showing that spores of the harmless bacterium, bacillus globegii (BG), can be used as a simulant for the radioactive aerosols. An aerosol generator of Lauterbach type was developed which will produce an essentially monodisperse aerosol at the rate of 109 spores/min. Analytical techniques have been established which give reproducible results. Preliminary field tests have been conducted to check out the components of the system. Preliminary tests of protective devices, such as ordinary vacuum sweepers, have given protection factors of over 1000

  8. Stratospheric aerosols

    International Nuclear Information System (INIS)

    Stratospheric aerosol measurements can provide both spatial and temporal data of sufficient resolution to be of use in climate models. Relatively recent results from a wide range of instrument techniques for measuring stratospheric aerosol parameters are described. Such techniques include impactor sampling, lidar system sensing, filter sampling, photoelectric particle counting, satellite extinction-sensing using the sun as a source, and optical depth probing, at sites mainly removed from tropospheric aerosol sources. Some of these techniques have also had correlative and intercomparison studies. The main methods for determining the vertical profiles of stratospheric aerosols are outlined: lidar extinction measurements from satellites; impactor measurements from balloons and aircraft; and photoelectric particle counter measurements from balloons, aircraft, and rockets. The conversion of the lidar backscatter to stratospheric aerosol mass loading is referred to. Absolute measurements of total solar extinction from satellite orbits can be used to extract the aerosol extinction, and several examples of vertical profiles of extinction obtained with the SAGE satellite are given. Stratospheric mass loading can be inferred from extinction using approximate linear relationships but under restrictive conditions. Impactor sampling is essentially the only method in which the physical nature of the stratospheric aerosol is observed visually. Vertical profiles of stratospheric aerosol number concentration using impactor data are presented. Typical profiles using a dual-size-range photoelectric dustsonde particle counter are given for volcanically disturbed and inactive periods. Some measurements of the global distribution of stratospheric aerosols are also presented. Volatility measurements are described, indicating that stratospheric aerosols are composed primarily of about 75% sulfuric acid and 25% water

  9. ViPAR

    DEFF Research Database (Denmark)

    Carter, Kim W; Francis, Richard W; Bresnahan, M; Gissler, M; Grønborg, T K; Gross, R; Gunnes, N; Hammond, G; Hornig, M; Hultman, C M; Huttunen, J; Langridge, A; Leonard, H; Newman, S; Parner, E T; Petersson, G; Reichenberg, A; Sandin, S; Schendel, Diana; Schalkwyk, L; Sourander, A; Steadman, C; Stoltenberg, C; Suominen, A; Surén, P; Susser, E; Sylvester Vethanayagam, A; Yusof, Z

    2015-01-01

    free and open source methods to provide researchers with a web-based platform to analyse datasets housed in disparate locations. METHODS: Database federation permits controlled access to remotely located datasets from a central location. The Secure Shell protocol allows data to be securely exchanged......PAR infrastructure, remote sites manage their own harmonized research dataset in a database hosted at their site, while a central server hosts the data federation component and a secure analysis portal. When an analysis is initiated, requested data are retrieved from each remote site and virtually pooled at the...... central site. The data are then analysed by statistical software and, on completion, results of the analysis are returned to the user and the virtually pooled data are removed from memory. CONCLUSIONS: ViPAR is a secure, flexible and powerful analysis platform built on open source technology that is...

  10. Tropospheric Aerosols

    Science.gov (United States)

    Buseck, P. R.; Schwartz, S. E.

    2003-12-01

    It is widely believed that "On a clear day you can see forever," as proclaimed in the 1965 Broadway musical of the same name. While an admittedly beautiful thought, we all know that this concept is only figurative. Aside from Earth's curvature and Rayleigh scattering by air molecules, aerosols - colloidal suspensions of solid or liquid particles in a gas - limit our vision. Even on the clearest day, there are billions of aerosol particles per cubic meter of air.Atmospheric aerosols are commonly referred to as smoke, dust, haze, and smog, terms that are loosely reflective of their origin and composition. Aerosol particles have arisen naturally for eons from sea spray, volcanic emissions, wind entrainment of mineral dust, wildfires, and gas-to-particle conversion of hydrocarbons from plants and dimethylsulfide from the oceans. However, over the industrial period, the natural background aerosol has been greatly augmented by anthropogenic contributions, i.e., those produced by human activities. One manifestation of this impact is reduced visibility (Figure 1). Thus, perhaps more than in other realms of geochemistry, when considering the composition of the troposphere one must consider the effects of these activities. The atmosphere has become a reservoir for vast quantities of anthropogenic emissions that exert important perturbations on it and on the planetary ecosystem in general. Consequently, much recent research focuses on the effects of human activities on the atmosphere and, through them, on the environment and Earth's climate. For these reasons consideration of the geochemistry of the atmosphere, and of atmospheric aerosols in particular, must include the effects of human activities. (201K)Figure 1. Impairment of visibility by aerosols. Photographs at Yosemite National Park, California, USA. (a) Low aerosol concentration (particulate matter of aerodynamic diameter less than 2.5 μm, PM2.5=0.3 μg m-3; particulate matter of aerodynamic diameter less than 10

  11. MODIS-derived daily PAR simulation from cloud-free images and its validation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Liangfu; Gu, Xingfa; Tian, Guoliang [State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101 (China); The Center for National Spaceborne Demonstration, Beijing 100101 (China); Gao, Yanhua [State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101 (China); Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); Yang, Lei [State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101 (China); Jilin University, Changchun 130026 (China); Liu, Qinhuo [State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101 (China)

    2008-06-15

    In this paper, a MODIS-derived daily PAR (photosynthetically active radiation) simulation model from cloud-free image over land surface has been developed based on Bird and Riordan's model. In this model, the total downwelling spectral surface irradiance is divided into two parts: one is beam irradiance, and another is diffuse irradiance. The attenuation of solar beam irradiance comprises scattering by the gas mixture, absorption by ozone, the gas mixture and water vapor, and scattering and absorption by aerosols. The diffuse irradiance is scattered out of the direct beam and towards the surface. The multiple ground-air interactions have been taken into account in the diffuse irradiance model. The parameters needed in this model are atmospheric water vapor content, aerosol optical thickness and spectral albedo ranging from 400 nm to 700 nm. They are all retrieved from MODIS data. Then, the instantaneous photosynthetically available radiation (IPAR) is integrated by using a weighted sum at each of the visible MODIS wavebands. Finally, a daily PAR is derived by integration of IPAR. In order to validate the MODIS-derived PAR model, we compared the field PAR measurements in 2003 and 2004 against the simulated PAR. The measurements were made at the Qianyanzhou ecological experimental station, Chinese Ecosystem Research Network. A total of 54 days of cloud-free MODIS L1B level images were used for the PAR simulation. Our results show that the simulated PAR is consistent with field measurements, where the correlation coefficient of linear regression between calculated PAR and measured PAR is 0.93396. However, there were some uncertainties in the comparison of 1 km pixel PAR with the tower flux stand measurement. (author)

  12. Instantaneous aerosol dynamics in a turbulent flow

    KAUST Repository

    Zhou, Kun

    2012-01-01

    Dibutyl phthalate aerosol particles evolution dynamics in a turbulent mixing layer is simulated by means of direct numerical simulation for the flow field and the direct quadrature method of moments for the aerosol evolution. Most par-ticles are nucleated in a thin layer region corresponding to a specific narrow temperature range near the cool stream side. However, particles undergo high growth rate on the hot stream side due to condensation. Coagulation decreases the total particle number density at a rate which is highly correlated to the in-stantaneous number density.

  13. Eduquer par la musique

    OpenAIRE

    Zhe, Ji

    2011-01-01

    La politique et l’éducation sont indissociables dans les tentatives de promouvoir le confucianisme en Chine contemporaine. L’union alors célébrée du sacré, du pouvoir et du savoir s’inscrit en tension avec une modernité d’abord caractérisée par la différenciation des institutions et des valeurs. Partant de ce constat, l’article étudie le cas particulier d’une société engagée depuis 2000 dans l’initiation des enfants à la musique classique et dans la promotion de la « culture de soi » chez les...

  14. Indoor aerosols

    DEFF Research Database (Denmark)

    Morawska, L.; Afshari, Alireza; N. Bae, G.;

    2013-01-01

    understanding of the risks posed by personal exposure to indoor aerosols. Limited studies assessing integrated daily residential exposure to just one particle size fraction, ultrafine particles, show that the contribution of indoor sources ranged from 19% to 76%. This indicates a strong dependence on resident...

  15. Comparison of aerosol and bioaerosol collection on air filters

    OpenAIRE

    Miaskiewicz-Peska, Ewa; Lebkowska, Maria

    2011-01-01

    Air filters efficiency is usually determined by non-biological test aerosols, such as potassium chloride particles, Arizona dust or di-ethyl-hexyl-sebacate (DEHS) oily liquid. This research was undertaken to asses, if application of non-biological aerosols reflects air filters capacity to collect particles of biological origin. The collection efficiency for non-biological aerosol was tested with the PALAS set and ISO Fine Test Dust. Flow rate during the filtration process was 720 l/h, and par...

  16. Elusloom lennukiga puhkusele / Inge Parring

    Index Scriptorium Estoniae

    Parring, Inge

    2003-01-01

    Ilmunud ka: Delovõje Vedomosti 1. okt. lk. 13. Air Cargo Estonia/ACE Logisticsi müügijuht Inge Parring tutvustab elusloomade transpordivõimalusi. Vt. samas: Loomade transportimiseks vajalikud dokumendid

  17. Datation par thermoluminescence

    Directory of Open Access Journals (Sweden)

    1976-01-01

    Full Text Available Depuis 1953, de nombreux chercheurs se sont intéressés à la datation par thermoluminescence de minéraux anciennement brûlés ou cuits. Dans ce travail, après avoir rappelé quelques principes physiques de la thermoluminescence, on présente cette méthode de datation en mettant l'accent sur le mécanisme thermoluminescent dans une poterie. Ainsi la dose d'irradiation reçue par le matériau étant proportionnelle au temps écoulé depuis le 'zéro archéologique', il est possible de déterminer 'la dose archéologique' et d'en déduire l'âge de l'échantillon après avoir calculé la dose d'irradiation annuelle. La réalisation pratique d'un tel ensemble de mesure est cependant très ardue. Dans un prochain article, E. A. Decamps et A. Roman montreront des résultats relatifs à la thermoluminescence d'échantillons de quartz naturels, purs et dopés et la mise au point d'une nouvelle méthode de datation. Desde 1953, muchos investigadores se han interesado en la datación por termoluminiscencia de minerales antiguamente quemados o cocidos. Dentro de este trabajo, luego de haber recordado algunos principios físicos de la termoluminiscencia, se presenta este método de datación poniendo mayor atención en el mecanismo termoluminescente en una vasija de metal o de barro. Siendo proporcional la dosis de irradiación recibida al tiempo transcurrido desde el 'cero arqueológico', es posible determinar 'la dosis arqueológica', y deducir la edad de la muestra luego de haber calculado la dosis de irradiación anual. La realización práctica de un trabajo de tal dimensión es sin embargo muy ardua. En un próximo artículo, E. A. Decamps y A. Román presentarán los resultados relativos a la termoluminiscencia de muestras de cuarzo naturales, puras y dopadas y la elaboración de un nuevo método de datación. Since 1953, a number of scientists have been concerned with the use of thermoluminescence for the dating of burned or fired minerals

  18. Aerosol filtration

    International Nuclear Information System (INIS)

    This report summarizes the work on the development of fibre metallic prefilters to be placed upstream of HEPA filters for the exhaust gases of nuclear process plants. Investigations at ambient and high temperature were carried out. Measurements of the filtration performance of Bekipor porous webs and sintered mats were performed in the AFLT (aerosol filtration at low temperature) unit with a throughput of 15 m3/h. A parametric study on the influence of particle size, fibre diameter, number of layers and superficial velocity led to the optimum choice of the working parameters. Three selected filter types were then tested with polydisperse aerosols using a candle-type filter configuration or a flat-type filter configuration. The small-diameter candle type is not well suited for a spraying nozzles regeneration system so that only the flat-type filter was retained for high-temperature tests. A high-temperature test unit (AFHT) with a throughput of 8 to 10 m3/h at 4000C was used to test the three filter types with an aerosol generated by high-temperature calcination of a simulated nitric acid waste solution traced with 134Cs. The regeneration of the filter by spray washing and the effect of the regeneration on the filter performance was studied for the three filter types. The porous mats have a higher dust loading capacity than the sintered web which means that their regeneration frequency can be kept lower

  19. Par Pond vegetation status 1996

    International Nuclear Information System (INIS)

    The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the newly emergent, shoreline aquatic plant communities of Par Pond began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level. These surveys continued in July, September, and late October, 1995, and into the early spring and late summer of 1996. Communities similar to the pre-drawdown, Par Pond aquatic plant communities continue to become re-established. Emergent beds of maidencane, lotus, waterlily, watershield, and Pontederia are extensive and well developed. Measures of percent cover, width of beds, and estimates of area of coverage with satellite data indicate regrowth within two years of from 40 to 60% of levels prior to the draw down. Cattail occurrence continued to increase during the summer of 1996, especially in the former warm arm of Par Pond, but large beds common to Par Pond prior to the draw down still have not formed. Lotus has invaded and occupies many of the areas formerly dominated by cattail beds. To track the continued development of macrophytes in Par Pond, future surveys through the summer and early fall of 1997, along with the evaluation of satellite data to map the extent of the macrophyte beds of Par Pond, are planned

  20. TOMS Absorbing Aerosol Index

    Data.gov (United States)

    Washington University St Louis — TOMS_AI_G is an aerosol related dataset derived from the Total Ozone Monitoring Satellite (TOMS) Sensor. The TOMS aerosol index arises from absorbing aerosols such...

  1. Immunopathogenic Background of Pars Planitis.

    Science.gov (United States)

    Przeździecka-Dołyk, Joanna; Węgrzyn, Agnieszka; Turno-Kręcicka, Anna; Misiuk-Hojło, Marta

    2016-04-01

    Pars planitis is defined as an intermediate uveitis of unknown background of systemic disease with characteristic formations such as vitreous snowballs, snowbanks and changes in peripheral retina. The incidence of pars planitis varies 2.4-15.4 % of the uveitis patients. The pathogenesis of the disease is to be determined in future. Clinical and histopathological findings suggest an autoimmune etiology, most likely as a reaction to endogenous antigen of unknown source, with T cells predominant in both vitreous and pars plana infiltrations. T cells subsets play an important role as a memory-effector peripheral cell. Snowbanks are formed as an effect of post inflammatory glial proliferation of fibrous astrocytes. There is also a genetic predisposition for pars planitis by human leukocyte antigen and several other genes. A coexistence of multiple sclerosis and optic neuritis has been described in numerous studies. Epiretinal membrane, cataract, cystoid macular edema, retinal detachment, retinal vasculitis, neovascularization, vitreous peripheral traction, peripheral hole formation, vitreous hemorrhage, disc edema are common complications observed in pars planitis. There is a need to expand the knowledge of the pathogenic and immunologic background of the pars planitis to create an accurate pharmacological treatment. PMID:26438050

  2. Aerosol Observation System

    Data.gov (United States)

    Oak Ridge National Laboratory — The aerosol observation system (AOS) is the primary Atmospheric Radiation Measurement (ARM) platform for in situ aerosol measurements at the surface. The principal...

  3. suPAR: the molecular crystal ball

    DEFF Research Database (Denmark)

    Thunø, Maria; Macho, Betina; Eugen-Olsen, Jesper

    2009-01-01

    soluble urokinase Plasminogen Activator Receptor (suPAR) levels reflect inflammation and elevated suPAR levels are found in several infectious diseases and cancer. suPAR exists in three forms; suPAR(I-III), suPAR(II-III) and suPAR(I) which show different properties due to structural differences...... inflammation and pathogenic processes. We focus on the molecular mechanisms of the suPAR fragments and the link to the inflammatory process,as this could lead to medical applications in infectious and pathological conditions....

  4. ParAB Partition Dynamics in Firmicutes: Nucleoid Bound ParA Captures and Tethers ParB-Plasmid Complexes

    OpenAIRE

    Lioy, Virginia S.; Andrea Volante; Nora E Soberón; Rudi Lurz; Silvia Ayora; Alonso, Juan C.

    2015-01-01

    In Firmicutes, small homodimeric ParA-like (δ2) and ParB-like (ω2) proteins, in concert with cis-acting plasmid-borne parS and the host chromosome, secure stable plasmid inheritance in a growing bacterial population. This study shows that (ω:YFP)2 binding to parS facilitates plasmid clustering in the cytosol. (δ:GFP)2 requires ATP binding but not hydrolysis to localize onto the cell's nucleoid as a fluorescent cloud. The interaction of (δ:CFP)2 or δ2 bound to the nucleoid with (ω:YFP)2 foci f...

  5. Designing Tone Reservation PAR Reduction

    Directory of Open Access Journals (Sweden)

    Johansson Albin

    2006-01-01

    Full Text Available Tone reservation peak-to-average (PAR ratio reduction is an established area when it comes to bringing down signal peaks in multicarrier (DMT or OFDM systems. When designing such a system, some questions often arise about PAR reduction. Is it worth the effort? How much can it give? How much does it give depending on the parameter choices? With this paper, we attempt to answer these questions without resolving to extensive simulations for every system and every parameter choice. From a specification of the allowed spectrum, for instance prescribed by a standard, including a PSD-mask and a number of tones, we analytically predict achievable PAR levels, and thus implicitly suggest parameter choices. We use the ADSL2 and ADSL2+ systems as design examples.

  6. Aerosol typing - key information from aerosol studies

    Science.gov (United States)

    Mona, Lucia; Kahn, Ralph; Papagiannopoulos, Nikolaos; Holzer-Popp, Thomas; Pappalardo, Gelsomina

    2016-04-01

    Aerosol typing is a key source of aerosol information from ground-based and satellite-borne instruments. Depending on the specific measurement technique, aerosol typing can be used as input for retrievals or represents an output for other applications. Typically aerosol retrievals require some a priori or external aerosol type information. The accuracy of the derived aerosol products strongly depends on the reliability of these assumptions. Different sensors can make use of different aerosol type inputs. A critical review and harmonization of these procedures could significantly reduce related uncertainties. On the other hand, satellite measurements in recent years are providing valuable information about the global distribution of aerosol types, showing for example the main source regions and typical transport paths. Climatological studies of aerosol load at global and regional scales often rely on inferred aerosol type. There is still a high degree of inhomogeneity among satellite aerosol typing schemes, which makes the use different sensor datasets in a consistent way difficult. Knowledge of the 4d aerosol type distribution at these scales is essential for understanding the impact of different aerosol sources on climate, precipitation and air quality. All this information is needed for planning upcoming aerosol emissions policies. The exchange of expertise and the communication among satellite and ground-based measurement communities is fundamental for improving long-term dataset consistency, and for reducing aerosol type distribution uncertainties. Aerosol typing has been recognized as one of its high-priority activities of the AEROSAT (International Satellite Aerosol Science Network, http://aero-sat.org/) initiative. In the AEROSAT framework, a first critical review of aerosol typing procedures has been carried out. The review underlines the high heterogeneity in many aspects: approach, nomenclature, assumed number of components and parameters used for the

  7. Par Pond Fish, Water, and Sediment Chemistry

    International Nuclear Information System (INIS)

    The objectives of this report are to describe the Par Pond fish community and the impact of the drawdown and refill on the community, describe contaminant levels in Par Pond fish, sediments, and water and indicate how contaminant concentrations and distributions were affected by the drawdown and refill, and predict possible effects of future water level fluctuations in Par Pond

  8. Aerosol mobility size spectrometer

    Science.gov (United States)

    Wang, Jian; Kulkarni, Pramod

    2007-11-20

    A device for measuring aerosol size distribution within a sample containing aerosol particles. The device generally includes a spectrometer housing defining an interior chamber and a camera for recording aerosol size streams exiting the chamber. The housing includes an inlet for introducing a flow medium into the chamber in a flow direction, an aerosol injection port adjacent the inlet for introducing a charged aerosol sample into the chamber, a separation section for applying an electric field to the aerosol sample across the flow direction and an outlet opposite the inlet. In the separation section, the aerosol sample becomes entrained in the flow medium and the aerosol particles within the aerosol sample are separated by size into a plurality of aerosol flow streams under the influence of the electric field. The camera is disposed adjacent the housing outlet for optically detecting a relative position of at least one aerosol flow stream exiting the outlet and for optically detecting the number of aerosol particles within the at least one aerosol flow stream.

  9. Facility of aerosol filtration

    International Nuclear Information System (INIS)

    Said invention relates to a facility of aerosol filtration, particularly of sodium aerosols. Said facility is of special interest for fast reactors where sodium fires involve the possibility of high concentrations of sodium aerosols which soon clog up conventional filters. The facility intended for continuous operation, includes at the pre-filtering stage, means for increasing the size of the aerosol particles and separating clustered particles (cyclone separator)

  10. Aerosol satellite remote sensing

    NARCIS (Netherlands)

    Veefkind, Joris Pepijn

    2001-01-01

    Aerosols are inportant for many processes in the atmosphere. Aerosols are a leading uncertainty in predicting global climate change, To a large extent this uncertainty is caused by a lack of knowledge on the occurrence and concentration of aerosols. On global scale, this information can only be o

  11. Data available for the evaluation of the risks related to the bio-aerosols emitted by the domestic wastes storage; Donnees disponibles pour l'evaluation des risques lies aux bioaerosols emis par les installations de stockage des dechets menagers et assimiles

    Energy Technology Data Exchange (ETDEWEB)

    Delery, L.

    2003-12-15

    The dusts production during exploitation in cells is the main source of bio-aerosols emission in storage centers. This report presents data on biological characterization of domestic wastes and the related atmospheric emissions. It concludes that the sanitary risk for the residents is weak and the 200 m area decided by the regulation is sufficient. Meanwhile it is recommended to control the emission levels during particularly meteorological conditions as humid, windy and not very sunny. (A.L.B.)

  12. Aerosol-Cloud-Precipitation Interactions in WRF Model:Sensitivity to Autoconversion Parameterization

    Institute of Scientific and Technical Information of China (English)

    解小宁; 刘晓东

    2015-01-01

    Cloud-to-rain autoconversion process is an important player in aerosol loading, cloud morphology, and precipitation variations because it can modulate cloud microphysical characteristics depending on the par-ticipation of aerosols, and aff ects the spatio-temporal distribution and total amount of precipitation. By applying the Kessler, the Khairoutdinov-Kogan (KK), and the Dispersion autoconversion parameterization schemes in a set of sensitivity experiments, the indirect eff ects of aerosols on clouds and precipitation are investigated for a deep convective cloud system in Beijing under various aerosol concentration backgrounds from 50 to 10000 cm−3. Numerical experiments show that aerosol-induced precipitation change is strongly dependent on autoconversion parameterization schemes. For the Kessler scheme, the average cumulative precipitation is enhanced slightly with increasing aerosols, whereas surface precipitation is reduced signifi-cantly with increasing aerosols for the KK scheme. Moreover, precipitation varies non-monotonically for the Dispersion scheme, increasing with aerosols at lower concentrations and decreasing at higher concentrations. These diff erent trends of aerosol-induced precipitation change are mainly ascribed to diff erences in rain wa-ter content under these three autoconversion parameterization schemes. Therefore, this study suggests that accurate parameterization of cloud microphysical processes, particularly the cloud-to-rain autoconversion process, is needed for improving the scientifi c understanding of aerosol-cloud-precipitation interactions.

  13. Aerosol Chemistry Between Two Oceans: Auckland’s Urban Aerosol

    Czech Academy of Sciences Publication Activity Database

    Coulson, G.; Olivares, G.; Salmond, J.; Talbot, Nicholas

    -: Italian Aerosol Society, 2015. ISBN N. [European Aerosol Conference EAC 2015. Milano (IT), 06.09.2015-11.09.2015] Institutional support: RVO:67985858 Keywords : urban pollution * aerosol processing * New Zealand Subject RIV: CF - Physical ; Theoretical Chemistry

  14. Performance testing of passive autocatalytic recombiners (PARs)

    International Nuclear Information System (INIS)

    Passive autocatalytic recombiners (PARs) have been under consideration in the U.S. as a combustible gas control system in advanced light water reactor (ALWR) containments for design basis and severe accidents. PARs do not require a source of power. Instead they use palladium or platinum as a catalyst to recombine hydrogen and oxygen gases into water vapor upon contact with the catalyst. Energy from the recombination of hydrogen with oxygen is released at a relatively slow but continuous rate into the containment which prevents the pressure from becoming too high. The heat produced creates strong buoyancy effects which increases the influx of the surrounding gases to the recombiner. These natural convective flow currents promote mixing of combustible gases in the containment. PARs are self-starting and self-feeding under a very wide range of conditions. The recombination rate of the PAR system needs to be great enough to keep the concentration of hydrogen (or oxygen) below acceptable limits. There are several catalytic recombiner concepts under development worldwide. The USNRC is evaluating a specific design of a PAR which is in an advanced stage of engineering development and has been proposed for ALWR designs. Sandia National laboratories (SNL), under the sponsorship and the direction of the USNRC, is conducting an experimental program to evaluate the performance of PARs. The PAR will be tested at the SURTSEY facility at SNL. The test plan currently includes the following experiments: experiments will be conducted to define the startup characteristics of PARs (i.e., to define what is the lowest hydrogen concentration that the PAR starts recombining the hydrogen with oxygen); experiments will be used to define the hydrogen depletion rate of PARs as a function of hydrogen concentration; and experiments will be used to define the PAR performance in the presence of high concentrations of steam. (author)

  15. Impact of Biomass Burning Aerosols on the Biosphere over Amazonia

    Science.gov (United States)

    Malavelle, F.; Haywood, J.; Mercado, L.; Folberth, G.; Bellouin, N.

    2014-12-01

    Biomass burning (BB) smoke from deforestation and the burning of agricultural waste emit a complex cocktail of aerosol particles and gases. BB emissions show a regional hotspot over South America on the edges of Amazonia. These major perturbations and impacts on surface temperature, surface fluxes, chemistry, radiation, rainfall, may have significant consequent impacts on the Amazon rainforest, the largest and most productive carbon store on the planet. There is therefore potential for very significant interaction and interplay between aerosols, clouds, radiation and the biosphere in the region. Terrestrial carbon production (i.e. photosynthesis) is intimately tied to the supply of photosynthetically active radiation (PAR - i.e. wavelengths between 300-690 nm). PAR in sufficient intensity and duration is critical for plant growth. However, if a decrease in total radiation is accompanied by an increase in the component of diffuse radiation, plant productivity may increase due to higher light use efficiency per unit of PAR and less photosynthetic saturation. This effect, sometimes referred as diffuse light fertilization effect, could have increased the global land carbon sink by approximately one quarter during the global dimming period and is expected to be a least as important locally. By directly interacting with radiation, BB aerosols significantly reduce the total amount of PAR available to plant canopies. In addition, BB aerosols also play a centre role in cloud formation because they provide the necessary cloud condensation nuclei, hence indirectly altering the water cycle and the components and quantity of PAR. In this presentation, we use the recent observations from the South American Biomass Burning Analysis (SAMBBA) to explore the impact of radiation changes on the carbon cycle in the Amazon region caused by BB emissions. A parameterisation of the impact of diffuse and direct radiation upon photosynthesis rates and net primary productivity in the

  16. Sensitivity of aerosol direct radiative forcing to aerosol vertical profile

    OpenAIRE

    Chung, Chul E.; Choi, Jung-Ok

    2014-01-01

    Aerosol vertical profile significantly affects the aerosol direct radiative forcing at the TOA level. The degree to which the aerosol profile impacts the aerosol forcing depends on many factors such as presence of cloud, surface albedo and aerosol single scattering albedo (SSA). Using a radiation model, we show that for absorbing aerosols (with an SSA of 0.7–0.8) whether aerosols are located above cloud or below induces at least one order of magnitude larger changes of the aerosol forcing tha...

  17. Aerosols Science and Technology

    CERN Document Server

    Agranovski, Igor

    2011-01-01

    This self-contained handbook and ready reference examines aerosol science and technology in depth, providing a detailed insight into this progressive field. As such, it covers fundamental concepts, experimental methods, and a wide variety of applications, ranging from aerosol filtration to biological aerosols, and from the synthesis of carbon nanotubes to aerosol reactors.Written by a host of internationally renowned experts in the field, this is an essential resource for chemists and engineers in the chemical and materials disciplines across multiple industries, as well as ideal supplementary

  18. Par Pond vegetation status Summer 1995 -- Summary

    International Nuclear Information System (INIS)

    The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the newly emergent, shoreline aquatic plant communities of Par Pond began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level. These surveys continued in July, September, and late October, 1995. Communities similar to the pre-drawdown, Par Pond aquatic plant communities are becoming re-established. Emergent beds of maidencane, lotus, waterlily, and watershield are extensive and well developed. Cattail occurrence continued to increase during the summer, but large beds common to Par Pond prior to the drawdown have not formed. Estimates from SPOT HRV, remote sensing satellite data indicated that as much as 120 hectares of emergent wetlands vegetation may have been present along the Par Pond shoreline by early October, 1995. To track the continued development of macrophytes in Par Pond, future surveys throughout 1996 and 1997, along with the continued evaluation of satellite data to map the areal extent of the macrophyte beds of Par Pond, are planned

  19. Aerosol in the containment

    International Nuclear Information System (INIS)

    The US program LACE (LWR Aerosol Containment Experiments), in which Italy participates together with several European countries, Canada and Japan, aims at evaluating by means of a large scale experimental activity at HEDL the retention in the pipings and primary container of the radioactive aerosol released following severe accidents in light water reactors. At the same time these experiences will make available data through which the codes used to analyse the behaviour of the aerosol in the containment and to verify whether by means of the codes of thermohydraulic computation it is possible to evaluate with sufficient accuracy variable influencing the aerosol behaviour, can be validated. This report shows and compares the results obtained by the participants in the LACE program with the aerosol containment codes NAVA 5 and CONTAIN for the pre-test computations of the test LA 1, in which an accident called containment by pass is simulated

  20. Sea Spray Aerosols

    DEFF Research Database (Denmark)

    Butcher, Andrew Charles

    Aerosols are important climactically. Their specific emissions are key to reducing the uncertainty in global climate models. Marine aerosols make up the largest source of primary aerosols to the Earth's atmosphere. Uncertainty in marine aerosol mass and number flux lies in separating primary...... emissions produced directly from bubble bursting as the result of air entrainment from breaking waves and particles generated from secondary emissions of volatile organic compounds. In the first paper, we study the chemical properties of particles produced from several sea water proxies with the use of a...... cloud condensation nuclei ounter. Proxy solutions with high inorganic salt concentrations and some organics produce sea spray aerosol particles with little change in cloud condensation activity relative to pure salts. Comparison is made between a frit based method for bubble production and a plunging...

  1. Activity of recombinant trypsin isoforms on human proteinase-activated receptors (PAR): mesotrypsin cannot activate epithelial PAR-1, -2, but weakly activates brain PAR-1

    OpenAIRE

    Grishina, Zoryana; Ostrowska, Ewa; Halangk, Walter; Sahin-Tóth, Miklós; Reiser, Georg

    2005-01-01

    Trypsin-like serine proteinases trigger signal transduction pathways through proteolytic cleavage of proteinase-activated receptors (PARs) in many tissues. Three members, PAR-1, PAR-2 and PAR-4, are trypsin substrates, as trypsinolytic cleavage of the extracellular N terminus produces receptor activation. Here, the ability of the three human pancreatic trypsin isoforms (cationic trypsin, anionic trypsin and mesotrypsin (trypsin IV)) as recombinant proteins was tested on PARs.Using fura 2 [Ca2...

  2. Sugars in Antarctic aerosol

    Science.gov (United States)

    Barbaro, Elena; Kirchgeorg, Torben; Zangrando, Roberta; Vecchiato, Marco; Piazza, Rossano; Barbante, Carlo; Gambaro, Andrea

    2015-10-01

    The processes and transformations occurring in the Antarctic aerosol during atmospheric transport were described using selected sugars as source tracers. Monosaccharides (arabinose, fructose, galactose, glucose, mannose, ribose, xylose), disaccharides (sucrose, lactose, maltose, lactulose), alcohol-sugars (erythritol, mannitol, ribitol, sorbitol, xylitol, maltitol, galactitol) and anhydrosugars (levoglucosan, mannosan and galactosan) were measured in the Antarctic aerosol collected during four different sampling campaigns. For quantification, a sensitive high-pressure anion exchange chromatography was coupled with a single quadrupole mass spectrometer. The method was validated, showing good accuracy and low method quantification limits. This study describes the first determination of sugars in the Antarctic aerosol. The total mean concentration of sugars in the aerosol collected at the "Mario Zucchelli" coastal station was 140 pg m-3; as for the aerosol collected over the Antarctic plateau during two consecutive sampling campaigns, the concentration amounted to 440 and 438 pg m-3. The study of particle-size distribution allowed us to identify the natural emission from spores or from sea-spray as the main sources of sugars in the coastal area. The enrichment of sugars in the fine fraction of the aerosol collected on the Antarctic plateau is due to the degradation of particles during long-range atmospheric transport. The composition of sugars in the coarse fraction was also investigated in the aerosol collected during the oceanographic cruise.

  3. Radioecological implications of the Par Pond drawdown

    International Nuclear Information System (INIS)

    The drawdown of the Par Pond reservoir created dramatic alterations in this formerly stable lentic ecosystem. In addition, the radiation environment at Par Pond has changed significantly because of the exposure of Cesium 137-contaminated sediments and the appearance of new transport pathways to the terrestrial environment. In response to this situation, SREL was asked to study the radioecological implications of the reservoir drawdown. This report contains the objectives, methods, and results of the SREL study

  4. Submicron aerosols: a review

    International Nuclear Information System (INIS)

    Submicron aerosols, ranging in particle diameter from 0.1 μm to 0.001 μm, and in number concentration from 10,000 to 100,000 per cm3, are more or less continuously suspended in the atmosphere we breathe. They usually require in situ measurement of concentration and size distribution with instruments such as diffusion batteries and condensation nucleus counters. Laboratory measurements require the development of submicron aerosol generators. The development of several of these devices and their use in the laboratory and field to measure radioactive as well as inactive aerosols is described

  5. C9.A/14 steelwork joints de poutres par plaque frontale : assemblages par gousset

    CERN Document Server

    2015-01-01

    Les Tables de résistances ultimes des assemblages boulonnés par plaque frontale et par gousset, complétées par une description des modèles de calcul et des exemples d’application, ont pour but de faciliter la tâche de l'ingénieur et du constructeur. Cette première partie C9.A/14 contient les chapitres suivants: - Joints de poutres par plaque frontale en acier S235 et S355 - Assemblages par gousset en acier S235 et S355 Les Tables contiennent des données relatives à la géométrie ainsi que les valeurs de calcul correspondantes des résistances ultimes des assemblages ; elles remplacent le chapitre « Assemblages par plaques frontales et boulons HR » des anciennes Tables C9.1 de 1983 / 2002. Le calcul de ces assemblages par plaque frontale est basé sur les hypothèses du modèle de la méthode des composants décrite dans la norme SN EN 1993-1-8. Les vérifications sont effectuées selon la norme SIA 263:2013. Les assemblages par gousset remplacent les assemblages par double cornière, (telle...

  6. Regulatory cross-talk in the double par locus of plasmid pB171

    DEFF Research Database (Denmark)

    Ringgaard, Simon; Ebersbach, Gitte; Borch, Jonas; Gerdes, Kenn; Charbon, Gitte Ebersbach

    2007-01-01

    The double par locus of Escherichia coli virulence factor pB171 consists of two adjacent and oppositely oriented par loci of different types, called par1 and par2. par1 encodes an actin ATPase (ParM), and par2 encodes an oscillating, MinD-like ATPase (ParA). The par loci share a central cis...... partition and promoter repression complexes. Surprisingly, ParB repressed transcription of the noncognate par operon, indicating cross-talk and possibly epistasis between the two systems. The par promoters, P1 and P2, affected each other negatively. The DNA binding activities of ParR and ParB correlated...

  7. Aerosols from biomass combustion

    Energy Technology Data Exchange (ETDEWEB)

    Nussbaumer, T.

    2001-07-01

    This report is the proceedings of a seminar on biomass combustion and aerosol production organised jointly by the International Energy Agency's (IEA) Task 32 on bio energy and the Swiss Federal Office of Energy (SFOE). This collection of 16 papers discusses the production of aerosols and fine particles by the burning of biomass and their effects. Expert knowledge on the environmental impact of aerosols, formation mechanisms, measurement technologies, methods of analysis and measures to be taken to reduce such emissions is presented. The seminar, visited by 50 participants from 11 countries, shows, according to the authors, that the reduction of aerosol emissions resulting from biomass combustion will remain a challenge for the future.

  8. Sodium oxide aerosol filtration

    International Nuclear Information System (INIS)

    In the scope of the sodium aerosol trapping research effort by the CEA/DSN, the retention capacity and yield were measured for very high efficiency fiberglass filters and several types of prefilters (cyclone agglomerator, fabric prefilters, water scrubbers). (author)

  9. Emergency protection from aerosols

    International Nuclear Information System (INIS)

    Expedient methods were developed that could be used by an average person, using only materials readily available, to protect himself and his family from injury by toxic (e.g., radioactive) aerosols. The most effective means of protection was the use of a household vacuum cleaner to maintain a small positive pressure on a closed house during passage of the aerosol cloud. Protection factors of 800 and above were achieved

  10. Emergency Protection from Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Cristy, G.A.

    2001-11-13

    Expedient methods were developed that could be used by an average person, using only materials readily available, to protect himself and his family from injury by toxic (e.g., radioactive) aerosols. The most effective means of protection was the use of a household vacuum cleaner to maintain a small positive pressure on a closed house during passage of the aerosol cloud. Protection factors of 800 and above were achieved.

  11. MISR Aerosol Typing

    Science.gov (United States)

    Kahn, Ralph A.

    2014-01-01

    AeroCom is an open international initiative of scientists interested in the advancement of the understanding of global aerosol properties and aerosol impacts on climate. A central goal is to more strongly tie and constrain modeling efforts to observational data. A major element for exchanges between data and modeling groups are annual meetings. The meeting was held September 20 through October 2, 1014 and the organizers would like to post the presentations.

  12. Structural analysis of the ParR/parC plasmid partition complex

    DEFF Research Database (Denmark)

    Møller-Jensen, Jakob; Ringgaard, Simon; Mercogliano, Christopher P;

    2007-01-01

    Accurate DNA partition at cell division is vital to all living organisms. In bacteria, this process can involve partition loci, which are found on both chromosomes and plasmids. The initial step in Escherichia coli plasmid R1 partition involves the formation of a partition complex between the DNA....... coli plasmid pB171. ParR forms a tight dimer resembling a large family of dimeric ribbon-helix-helix (RHH)2 site-specific DNA-binding proteins. Crystallographic and electron microscopic data further indicate that ParR dimers assemble into a helix structure with DNA-binding sites facing outward. Genetic...... and biochemical experiments support a structural arrangement in which the centromere-like parC DNA is wrapped around a ParR protein scaffold. This structure holds implications for how ParM polymerization drives active DNA transport during plasmid partition....

  13. The Expression of the Thrombin Receptors PAR-3 and PAR-4 is Downregulated in Pancreatic Cancer Cell Lines

    Directory of Open Access Journals (Sweden)

    Claudia Rudroff

    2015-05-01

    Full Text Available Background: Patients with pancreatic cancer frequently suffer from thrombosis as a consequence of excess thrombin generation. In addition to its role in the plasmatic coagulation cascade, thrombin induces numerous cellular effects by activating a unique group of G-protein-coupled receptors on the cell membrane, the proteinase-activated receptors (PARs. At present, PAR-1, PAR-3 and PAR-4 are known to be activated by thrombin. We previously demonstrated a putative role for PAR-1 in pancreatic cancer progression, but little is known about the physiological and pathophysiological roles of PAR-3 and PAR-4. In the present study, we examined the expression patterns of PAR-3 and PAR-4 in pancreatic tissue and pancreatic cancer cells. Methods: Tissue samples from three patients with pancreatic adenocarcinoma and six human pancreatic carcinoma cell lines were examined. Gene expression was analysed by RT-PCR and quantified by HPLC. Protein expression was determined by Western blot analysis. Data analysis was performed using ANOVA in SPSS. Results and Conclusion: In contrast to PAR-1, both PAR-3 and PAR-4 were expressed in healthy pancreases but downregulated in pancreatic cancer. The contrasting expression patterns of PAR-3 and PAR-4 compared with PAR-1 indicate that the mechanism that regulates the cellular effects of thrombin on tumor progression remains to be fully elucidated.

  14. Physical metrology of aerosols; Metrologie physique des aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Boulaud, D.; Vendel, J. [CEA Saclay, 91 - Gif-sur-Yvette (France). Inst. de Protection et de Surete Nucleaire

    1996-12-31

    The various detection and measuring methods for aerosols are presented, and their selection is related to aerosol characteristics (size range, concentration or mass range), thermo-hydraulic conditions (carrier fluid temperature, pressure and flow rate) and to the measuring system conditions (measuring frequency, data collection speed, cost...). Methods based on aerosol dynamic properties (inertial, diffusional and electrical methods) and aerosol optical properties (localized and integral methods) are described and their performances and applications are compared

  15. Traitement des eaux par électrofloculation

    OpenAIRE

    Cansado, Isabel

    1997-01-01

    Traitement des eaux par electrofloculation Les écosystèmes aquatiques sont très affectés par les eaux de rejet qui sont déversées dans les cours d’eau. La charge de ces eaux existe sous diverses formes: solutés, colloïdes ou particules. Il est important de traiter l’eau usée à de faibles coûts au lieu de la rejeter directement dans le milieu récepeteur. Dans le but d’améliorer les procédés physico-chimiques de déstabilisation des émulsions, nous étudions les traitements par électrocoagulat...

  16. Biological aerosol background characterization

    Science.gov (United States)

    Blatny, Janet; Fountain, Augustus W., III

    2011-05-01

    To provide useful information during military operations, or as part of other security situations, a biological aerosol detector has to respond within seconds or minutes to an attack by virulent biological agents, and with low false alarms. Within this time frame, measuring virulence of a known microorganism is extremely difficult, especially if the microorganism is of unknown antigenic or nucleic acid properties. Measuring "live" characteristics of an organism directly is not generally an option, yet only viable organisms are potentially infectious. Fluorescence based instruments have been designed to optically determine if aerosol particles have viability characteristics. Still, such commercially available biological aerosol detection equipment needs to be improved for their use in military and civil applications. Air has an endogenous population of microorganisms that may interfere with alarm software technologies. To design robust algorithms, a comprehensive knowledge of the airborne biological background content is essential. For this reason, there is a need to study ambient live bacterial populations in as many locations as possible. Doing so will permit collection of data to define diverse biological characteristics that in turn can be used to fine tune alarm algorithms. To avoid false alarms, improving software technologies for biological detectors is a crucial feature requiring considerations of various parameters that can be applied to suppress alarm triggers. This NATO Task Group will aim for developing reference methods for monitoring biological aerosol characteristics to improve alarm algorithms for biological detection. Additionally, they will focus on developing reference standard methodology for monitoring biological aerosol characteristics to reduce false alarm rates.

  17. Programmation par contraintes avec des fourmis

    OpenAIRE

    Khichane, Madjid; Albert, Patrick; Solnon, Christine

    2008-01-01

    National audience On explore dans cet article les possibilités d'intégration de la métaheuristique d'optimisation par colonies de fourmis (ACO) dans un langage de programmation par contraintes (PPC). L'idée est d'utiliser un langage de PPC pour décrire le problème à résoudre, ainsi que pour propager et vérifier les contraintes, et d'utiliser ACO pour guider la recherche de solutions. On illustre notre approche sur le problème d'ordonnancement de voitures.

  18. ParA and ParB coordinate chromosome segregation with cell elongation and division during Streptomyces sporulation.

    Science.gov (United States)

    Donczew, Magdalena; Mackiewicz, Paweł; Wróbel, Agnieszka; Flärdh, Klas; Zakrzewska-Czerwińska, Jolanta; Jakimowicz, Dagmara

    2016-04-01

    In unicellular bacteria, the ParA and ParB proteins segregate chromosomes and coordinate this process with cell division and chromosome replication. During sporulation of mycelial Streptomyces, ParA and ParB uniformly distribute multiple chromosomes along the filamentous sporogenic hyphal compartment, which then differentiates into a chain of unigenomic spores. However, chromosome segregation must be coordinated with cell elongation and multiple divisions. Here, we addressed the question of whether ParA and ParB are involved in the synchronization of cell-cycle processes during sporulation in Streptomyces To answer this question, we used time-lapse microscopy, which allows the monitoring of growth and division of single sporogenic hyphae. We showed that sporogenic hyphae stop extending at the time of ParA accumulation and Z-ring formation. We demonstrated that both ParA and ParB affect the rate of hyphal extension. Additionally, we showed that ParA promotes the formation of massive nucleoprotein complexes by ParB. We also showed that FtsZ ring assembly is affected by the ParB protein and/or unsegregated DNA. Our results indicate the existence of a checkpoint between the extension and septation of sporogenic hyphae that involves the ParA and ParB proteins. PMID:27248800

  19. SWANN ORGANIQUE (EN PASSANT PAR BECKETT PANOPTIQUE

    Directory of Open Access Journals (Sweden)

    Sjef Houppermans

    2013-12-01

    Full Text Available Comme quoi Swann a bel et bien un corps souffrant et jouissant. Comme quoi Swann absorbe le monde surtout par ses six sens. Comme quoi l´univers de Swann est une aire de dissémination que Samuel Beckett sonde exemplairement dans son étude de 1930.

  20. A Combined Global and Local Approach to Elucidate Spatial Organization of the Mycobacterial ParB-parS Partition

    International Nuclear Information System (INIS)

    Combining diverse sets of data at global (size, shape) and local (residue) scales is an emerging trend for elucidating the organization and function of the cellular assemblies. We used such a strategy, combining data from X-ray and neutron scattering with H/D-contrast variation and X-ray footprinting with mass spectrometry, to elucidate the spatial organization of the ParB-parS assembly from Mycobacterium tuberculosis. The ParB-parS participates in plasmid and chromosome segregation and condensation in predivisional bacterial cells. ParB polymerizes around the parS centromere(s) to form a higher-order assembly that serves to recruit cyto-skeletal ParA ATPases and SMC proteins for chromosome segregation. A hybrid model of the ParB-parS was built by combining and correlating computational models with experiment-derived information about size, shape, position of the symmetry axis within the shape, internal topology, DNA-protein interface, exposed surface patches, and prior knowledge. This first view of the ParB-parS leads us to propose how ParB spread on the chromosome to form a larger assembly.

  1. A Combined Global and Local Approach to Elucidate Spatial Organization of the Mycobacterial ParB-parS Partition Assembly

    Energy Technology Data Exchange (ETDEWEB)

    B Chaudhuri; S Gupta; V Urban; M Chance; R DMello; L Smith; K Lyons; J Gee

    2011-12-31

    Combining diverse sets of data at global (size, shape) and local (residue) scales is an emerging trend for elucidating the organization and function of the cellular assemblies. We used such a strategy, combining data from X-ray and neutron scattering with H/D-contrast variation and X-ray footprinting with mass spectrometry, to elucidate the spatial organization of the ParB-parS assembly from Mycobacterium tuberculosis. The ParB-parS participates in plasmid and chromosome segregation and condensation in predivisional bacterial cells. ParB polymerizes around the parS centromere(s) to form a higher-order assembly that serves to recruit cyto-skeletal ParA ATPases and SMC proteins for chromosome segregation. A hybrid model of the ParB-parS was built by combining and correlating computational models with experiment-derived information about size, shape, position of the symmetry axis within the shape, internal topology, DNA-protein interface, exposed surface patches, and prior knowledge. This first view of the ParB-parS leads us to propose how ParB spread on the chromosome to form a larger assembly.

  2. A Combined Global and Local Approach to Elucidate Spatial Organization of the Mycobacterial ParB-parS Partition

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhuri, Barnali [University of Buffalo, The State University of New York; Gupta, Sayan [Case Western Reserve University; Urban, Volker S [ORNL; Chance, Mark [Case Western Reserve University; D' Mello, Rhijuta [Case Western Reserve University; Smith, Lauren [University of Buffalo, The State University of New York; Lyons, Kelly [University of Buffalo, The State University of New York; Gee, Jessica [University of Buffalo, The State University of New York

    2010-01-01

    Combining diverse sets of data at global (size, shape) and local (residue) scales is an emerging trend for elucidating the organization and function of the cellular assemblies. We used such a strategy, combining data from X-ray and neutron scattering with H/D-contrast variation and X-ray footprinting with mass spectrometry, to elucidate the spatial organization of the ParB-parS assembly from Mycobacterium tuberculosis. The ParB-parS participates in plasmid and chromosome segregation and condensation in predivisional bacterial cells. ParB polymerizes around the parS centromere(s) to form a higher-order assembly that serves to recruit cyto-skeletal ParA ATPases and SMC proteins for chromosome segregation. A hybrid model of the ParB-parS was built by combining and correlating computational models with experiment-derived information about size, shape, position of the symmetry axis within the shape, internal topology, DNA-protein interface, exposed surface patches, and prior knowledge. This first view of the ParB-parS leads us to propose how ParB spread on the chromosome to form a larger assembly.

  3. Phosphorylation of Mycobacterium tuberculosis ParB participates in regulating the ParABS chromosome segregation system.

    Directory of Open Access Journals (Sweden)

    Grégory Baronian

    Full Text Available Here, we present for the first time that Mycobacterium tuberculosis ParB is phosphorylated by several mycobacterial Ser/Thr protein kinases in vitro. ParB and ParA are the key components of bacterial chromosome segregation apparatus. ParB is a cytosolic conserved protein that binds specifically to centromere-like DNA parS sequences and interacts with ParA, a weak ATPase required for its proper localization. Mass spectrometry identified the presence of ten phosphate groups, thus indicating that ParB is phosphorylated on eight threonines, Thr32, Thr41, Thr53, Thr110, Thr195, and Thr254, Thr300, Thr303 as well as on two serines, Ser5 and Ser239. The phosphorylation sites were further substituted either by alanine to prevent phosphorylation or aspartate to mimic constitutive phosphorylation. Electrophoretic mobility shift assays revealed a drastic inhibition of DNA-binding by ParB phosphomimetic mutant compared to wild type. In addition, bacterial two-hybrid experiments showed a loss of ParA-ParB interaction with the phosphomimetic mutant, indicating that phosphorylation is regulating the recruitment of the partitioning complex. Moreover, fluorescence microscopy experiments performed in the surrogate Mycobacterium smegmatis ΔparB strain revealed that in contrast to wild type Mtb ParB, which formed subpolar foci similar to M. smegmatis ParB, phoshomimetic Mtb ParB was delocalized. Thus, our findings highlight a novel regulatory role of the different isoforms of ParB representing a molecular switch in localization and functioning of partitioning protein in Mycobacterium tuberculosis.

  4. Regulatory cross-talk in the double par locus of plasmid pB171

    DEFF Research Database (Denmark)

    Ringgaard, Simon; Ebersbach, Gitte; Borch, Jonas;

    2007-01-01

    The double par locus of Escherichia coli virulence factor pB171 consists of two adjacent and oppositely oriented par loci of different types, called par1 and par2. par1 encodes an actin ATPase (ParM), and par2 encodes an oscillating, MinD-like ATPase (ParA). The par loci share a central cis-actin...... well with the observed transcriptional regulation of the par operons in vivo and in vitro. Integration host factor (IHF) was identified as a novel factor involved in par2-mediated plasmid partitioning....

  5. Les Brulures Chimiques Par Le Laurier Rose

    OpenAIRE

    Bakkali, H.; Ababou, M.; Nassim Sabah, T.; Moussaoui, A.; Ennouhi, A.; Fouadi, F.Z.; Siah, S.; Ihrai, H.

    2010-01-01

    Le laurier rose ou Nerium oleander est un arbuste qui pousse naturellement dans les régions méditerranéennes. Au Maroc on le trouve dans les lieux humides. Il est réputé par ses risques de toxicité systémique en cas d'empoisonnement à cause de la présence de deux alcaloïdes, surtout l'oléandrine. La littérature illustre des cas d'utilisation locale des feuilles de cette plante contre la gale, les hémorroïdes et les furoncles. Nous rapportons deux cas de brûlures chimiques par le laurier rose ...

  6. Annotation sémantique par classification

    OpenAIRE

    Toussaint, Yannick; Tenier, Sylvain

    2007-01-01

    Les systèmes actuels d'annotation sémantique exploitent peu les connaissances du domaine et fonctionnent essentiellement du texte vers l'ontologie. Pourtant, il est fréquent qu'un élément dans une page doive être annoté par un concept parce que certains autres éléments de cette même page sont annotés par d'autres concepts. Cet article propose une méthode d'annotation prenant en compte cette dépendance entre concepts, exprimée dans une ontologie sous forme de concepts définis. L'utilisation de...

  7. Recombination in the Human Pseudoautosomal Region PAR1

    OpenAIRE

    Anjali G Hinch; Nicolas Altemose; Nudrat Noor; Peter Donnelly; Simon R Myers

    2014-01-01

    The pseudoautosomal region (PAR) is a short region of homology between the mammalian X and Y chromosomes, which has undergone rapid evolution. A crossover in the PAR is essential for the proper disjunction of X and Y chromosomes in male meiosis, and PAR deletion results in male sterility. This leads the human PAR with the obligatory crossover, PAR1, to having an exceptionally high male crossover rate, which is 17-fold higher than the genome-wide average. However, the mechanism by which this o...

  8. Par Pond refill water quality sampling

    International Nuclear Information System (INIS)

    This study was designed to document anoxia and its cause in the event that the anoxia caused a fish kill. However, no fish kill was observed during this study, and dissolved oxygen and nutrient concentrations generally remained within the range expected for southeastern reservoirs. Par Pond water quality monitoring will continue during the second summer after refill as the aquatic macrophytes become reestablished and nutrients in the sediments are released to the water column

  9. Combined DSEK and Transconjunctival Pars Plana Vitrectomy

    Directory of Open Access Journals (Sweden)

    Mona Sane

    2016-01-01

    Full Text Available We report here three patients who underwent combined Descemet’s stripping with endothelial keratoplasty and transconjunctival pars plana vitrectomy for bullous keratopathy and posterior segment pathology. A surgical technique and case histories are described. Anatomic and visual outcomes of combined Descemet’s stripping with endothelial keratoplasty and vitrectomy were excellent. Our experience provides technical guidelines and limitations. The combined minimally invasive techniques allow for rapid anatomical recovery and return of function and visual acuity in a single sitting.

  10. Taare Zameen Par and dyslexic savants

    OpenAIRE

    Chakravarty, Ambar

    2009-01-01

    The film Taare Zameen Par (Stars upon the Ground) portrays the tormented life at school and at home of a child with dyslexia and his eventual success after his artistic talents are discovered by his art teacher at the boarding school. The film hints at a curious neurocognitive phenomenon of creativity in the midst of language disability, as exemplified in the lives of people like Leonardo da Vinci and Albert Einstein, both of whom demonstrated extraordinary creativity even though they were pr...

  11. Graphical aerosol classification method using aerosol relative optical depth

    Science.gov (United States)

    Chen, Qi-Xiang; Yuan, Yuan; Shuai, Yong; Tan, He-Ping

    2016-06-01

    A simple graphical method is presented to classify aerosol types based on a combination of aerosol optical thickness (AOT) and aerosol relative optical thickness (AROT). Six aerosol types, including maritime (MA), desert dust (DD), continental (CO), sub-continental (SC), urban industry (UI) and biomass burning (BB), are discriminated in a two dimensional space of AOT440 and AROT1020/440. Numerical calculations are performed using MIE theory based on a multi log-normal particle size distribution, and the AROT ranges for each aerosol type are determined. More than 5 years of daily observations from 8 representative aerosol sites are applied to the method to confirm spatial applicability. Finally, 3 individual cases are analyzed according to their specific aerosol status. The outcomes indicate that the new graphical method coordinates well with regional characteristics and is also able to distinguish aerosol variations in individual situations. This technique demonstrates a novel way to estimate different aerosol types and provide information on radiative forcing calculations and satellite data corrections.

  12. Aerosol samplers innovation possibilities

    International Nuclear Information System (INIS)

    The growing demand for an early detection of increased levels of the artificial radionuclides in the atmosphere resulted in the design and fabrication of an aerosol sampler with automated spectrometric unit providing online gamma spectrometry above the aerosol filter. Study was performed with two types of high volume samplers- SENYA JL-900 SnowWhite (900 m3/h) a SENYA JL-150 Hunter (150 m3/h). This work gives results of the design optimization with respect to the detector type, geometry of measurement, remote control and spectrometric evaluation 222Rn and 220Rn concentration fluctuations in the outdoor air are discussed with regard to the detection limit so the radionuclides expected after the NPP accident. (authors)

  13. An aerosol sampler

    International Nuclear Information System (INIS)

    That device is characterized in that, within a closed casing provided with a sealable opening, it comprises a storage rack for a plurality of stacked saucers, a sheath having a transverse slot for extracting said saucers separately from, or re-introducing same into, their respective sockets, a transfer gripping-member with its control mechanism for taking saucers from their respective sockets through said slot and moving them transversally, a sealing-plate mounted below the casing-opening, said plate being associated with a pushing mechanism, and a laterally retractable cover controlled by a separate mechanism for unsealing said casing opening and collecting aerosols on a saucer. That device can be used for taking samples of sodium aerosols

  14. Aerosol Observing System (AOS) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Jefferson, A

    2011-01-17

    The Aerosol Observing System (AOS) is a suite of in situ surface measurements of aerosol optical and cloud-forming properties. The instruments measure aerosol properties that influence the earth’s radiative balance. The primary optical measurements are those of the aerosol scattering and absorption coefficients as a function of particle size and radiation wavelength and cloud condensation nuclei (CCN) measurements as a function of percent supersaturation. Additional measurements include those of the particle number concentration and scattering hygroscopic growth. Aerosol optical measurements are useful for calculating parameters used in radiative forcing calculations such as the aerosol single-scattering albedo, asymmetry parameter, mass scattering efficiency, and hygroscopic growth. CCN measurements are important in cloud microphysical models to predict droplet formation.

  15. Aerosol characterization during project POLINAT

    Energy Technology Data Exchange (ETDEWEB)

    Hagen, D.E.; Hopkins, A.R.; Paladino, J.D.; Whitefield, P.D. [Missouri Univ., Rolla, MO (United States). Cloud and Aerosol Sciences Lab.; Lilenfeld, H.V. [McDonnell Douglas Aerospace-East, St. Louis, MO (United States)

    1997-12-31

    The objectives of the aerosol/particulate characterization measurements of project POLINAT (POLlution from aircraft emissions In the North ATlantic flight corridor) are: to search for aerosol/particulate signatures of air traffic emissions in the region of the North Atlantic Flight Corridor; to search for the aerosol/particulate component of large scale enhancement (`corridor effects`) of air traffic related species in the North Atlantic region; to determine the effective emission indices for the aerosol/particulate component of engine exhaust in both the near and far field of aircraft exhaust plumes; to measure the dispersion and transformation of the aerosol/particulate component of aircraft emissions as a function of ambient condition; to characterize background levels of aerosol/particulate concentrations in the North Atlantic Region; and to determine effective emission indices for engine exhaust particulates for regimes beyond the jet phase of plume expansion. (author) 10 refs.

  16. Dust and atmospheric aerosol

    International Nuclear Information System (INIS)

    The paper describes the types and characteristics of the various aerosol particles (by size effects, and origin) and goes on to discuss the composition of particulates and their variation in different places in Asia, and the origin of global particulate emissions from natural and anthropogenic sources. The effects of particulate matter on human health, visibility and climate are summarised. Techniques for control and abatement of particulate emissions are outlined. 10 refs., 4 figs., 11 tabs

  17. Photothermal spectroscopy of aerosols

    International Nuclear Information System (INIS)

    In situ aerosol absorption spectroscopy was performed using two novel photothermal detection schemes. The first, based on a photorefractive effect and coherent detection, called phase fluctuation optical heterodyne (PFLOH) spectroscopy, could, depending on the geometry employed, yield particle specific or particle and gas absorption data. Single particles of graphite as small as 1 μm were detected in the particle specific mode. In another geometrical configuration, the total absorption (both gas and particle) of submicron sized aerosols of ammonium sulfate particles in equilibrium with gaseous ammonia and water vapor were measured at varying CO2 laser frequencies. The specific absorption coefficient for the sulfate ion was measured to be 0.5 m2/g at 1087 cm-1. The absorption coefficient sensitivity of this scheme was less than or equal to 10-8 cm-1. The second scheme is a hybrid visible Mie scattering scheme incorporating photothermal modulation. Particle specific data on ammonium sulfate droplets were obtained. For chemically identical species, the relative absorption spectrum versus laser frequency can be obtained for polydisperse aerosol distributions directly from the data without the need for complex inverse scattering calculations

  18. Aerosol influence on radiative cooling

    OpenAIRE

    Grassl, Hartmut

    2011-01-01

    Aerosol particles have a complex index of refraction and therefore contribute to atmospheric emission and radiative cooling rates. In this paper calculations of the longwave flux divergence within the atmosphere at different heights are presented including water vapour and aerosol particles as emitters and absorbers. The spectral region covered is 5 to 100 microns divided into 23 spectral intervals. The relevant properties of the aerosol particles, the single scattering albedo and the extinct...

  19. Modelling of the aerosol deposition in a hydrogen catalytic recombiner

    Energy Technology Data Exchange (ETDEWEB)

    Vendel, J.; Studer, E.; Zavaleta, P. [Inst. de Protection et de Surete Nucleaire, Dept. de Prevention et d' Etudes des Accidents, Gif-sur-Yvette Cedex (France); Hadida, Ph. [Quasar Informatique, Paris (France)

    1997-03-01

    Catalytic recombiners are used to remove the hydrogen released in case of a severe accident in a nuclear power plant, so as to reduce the risk of deflagration or detonation. H{sub 2}PAR experiments are carried out to precise the behaviour of recombiners in term of poisoning by aerosols. Firstly, some calculations have been done with the Trio-EF code to assess the structure of convection loops in the experimental tent. We note that when the recombiner is active, it may have a strong influence on the flow inside the tent and may even interact with an other heat source such as a furnace. In the second part, we study the deposition of aerosols on catalytic plates for a given recombiner, when it is active or passive. We list the different mechanisms and quantify them by introducing the deposition velocity. In fact, thermophoresis appears to be the main mechanism, compared to brownian diffusion or difrusiophoresis, which governs aerosols deposition. It favours deposition on <> plates and acts against it for <> plates. (author)

  20. Modelling of the aerosol deposition in a hydrogen catalytic recombiner

    International Nuclear Information System (INIS)

    Catalytic recombiners are used to remove the hydrogen released in case of a severe accident in a nuclear power plant, so as to reduce the risk of deflagration or detonation. H2PAR experiments are carried out to precise the behaviour of recombiners in term of poisoning by aerosols. Firstly, some calculations have been done with the Trio-EF code to assess the structure of convection loops in the experimental tent. We note that when the recombiner is active, it may have a strong influence on the flow inside the tent and may even interact with an other heat source such as a furnace. In the second part, we study the deposition of aerosols on catalytic plates for a given recombiner, when it is active or passive. We list the different mechanisms and quantify them by introducing the deposition velocity. In fact, thermophoresis appears to be the main mechanism, compared to brownian diffusion or difrusiophoresis, which governs aerosols deposition. It favours deposition on > plates and acts against it for > plates. (author)

  1. Topics in current aerosol research

    CERN Document Server

    Hidy, G M

    1971-01-01

    Topics in Current Aerosol Research deals with the fundamental aspects of aerosol science, with emphasis on experiment and theory describing highly dispersed aerosols (HDAs) as well as the dynamics of charged suspensions. Topics covered range from the basic properties of HDAs to their formation and methods of generation; sources of electric charges; interactions between fluid and aerosol particles; and one-dimensional motion of charged cloud of particles. This volume is comprised of 13 chapters and begins with an introduction to the basic properties of HDAs, followed by a discussion on the form

  2. Nuclear aerosol test facility studies using plasma torch aerosol generator

    International Nuclear Information System (INIS)

    In order to study the behavior of aerosols released into the reactor containment following accidents, an experimental simulation facility, called Nuclear Aerosol Test Facility (NATF) has recently been built and commissioned in BARC. It mainly consists of a Test vessel for simulating the containment, plasma torch aerosol generator (PTAG) system for generating metal-based aerosols and aerosol monitoring instrumentation. The main component of the PTAG is a 40 kW dc plasma torch, powered by a constant current power supply, operating in a non-transferred arc mode. Optimal operating conditions of PTAG have been established. Experiments consist of injecting the aerosols of a given material for about 20 minutes into the vessel, simultaneously monitoring the concentrations at various points in the vessel. The measurements of the size distribution and mass concentrations in the vessel are carried out at periodic intervals. Various combination of experiments with different metals such as zinc, tin and manganese, under varying turbulence conditions (with and without keeping the fan continuously on) have been performed. The aerosols were generally found to be fractal aggregates with low fractal dimension (∼1.6). The mass depletion data have been subjected to theoretical analysis and validation exercises with available aerosol behavior codes. The results are further discussed. (author)

  3. Evaluation of the PAR corneal topography system

    Science.gov (United States)

    Jindal, Prateek; Cheung, Susan; Pirouzian, Amir; Keates, Richard H.; Ren, Qiushi

    1995-05-01

    The purpose of this study was to evaluate the raster photogrammetry based Corneal Topography System by determining: inter-operator variability, reproducibility of images, effects of defocused and decentered images, and the precision of data at different optical zones. 4 human cadaver eyes were used to study the inter-operator variability. To study the reproducibility of images, 3 human cadaver eyes and a test surface doped with flourescine (provided by PAR Vision Systems Corporation) were focused and their images taken four successive times. Defocused and decentered images were taken of 4 human cadaver eyes and four times of the test surface mentioned above. The precision of defocused/decentered cadaver eyes was evaluated at the following optical zones: 3 mm, 4 mm, 5 mm, and 6 mm. All human cadaver eyes used in the above experiments had their epithelial layer removed before imaging. Average inter-operator variability was 0.06 D. In reproducibility attempts, there was an average deviation of 0.28 D for the human cadaver eyes and 0.04 D for the test surface. The defocused and decentered test surface gave an average deviation of 0.09 D. Defocused and decentered cadaver eyes resulted in an average deviation of 0.52 D, 0.37 D, 0.24 D, and 0.22 D at optical zones of 3 mm, 4 mm, 5 mm, and 6 mm, respectively. The imaging method employed by PAR Vision Systems Corporation virtually eliminates inter-operator variability. The PAR Corneal Topography System's clinical usefulness, however, could be improved by improving the reproducibility of images, decreasing the sensitivity to spatial alignment, and increasing accuracy over smaller optical zones.

  4. Childhood Pars Planitis; Clinical Features and Outcomes

    Directory of Open Access Journals (Sweden)

    Homayoon Nikkhah

    2011-01-01

    Full Text Available Purpose: To evaluate the demographic and clinical features of childhood pars planitis, and to determine the therapeutic and visual outcomes of the disease. Methods: Medical records of pediatric patients (less than 16 years of age at diagnosis with pars planitis and at least 6 months of follow-up who were referred to Labbafinejad Medical Center, Tehran, Iran over a 22 year period were reviewed. Results: Overall, 117 eyes of 61 patients including 51 (83.6% male subjects were included. Mean age at the time of diagnosis was 7.8΁3.2 (range, 3-16 years. Mean best corrected visual acuity (BCVA was 0.88΁0.76 logMAR at presentation which improved to 0.39΁0.51 logMAR at final visit (P<0.001. Endotheliitis was present in 23 (19.6% eyes and was significantly more prevalent in subjects younger than 9 years (P=0.025. Cataract formation (41.9% and cystoid macular edema (19.7% were the most prevalent complications. Univariate regression analysis showed that better baseline visual acuity (OR=0.38, 95%CI 0.21-0.70, P=0.002, age older than 5 years at disease onset (OR=0.36, 95%CI 0.14-0.9, P=0.029, absence of endotheliitis (OR=0.39, 95%CI 0.15-0.99, P=0.047 and female gender (OR=3.77, 95%CI 1.03-13.93, P=0.046 were significantly associated with final BCVA of 20/40 or better. Conclusion: Childhood pars planitis was much more common among male subjects. Endotheliitis may be a sign of inflammation spillover and is more prevalent in younger patients. Visual prognosis is favorable in most patients with appropriate treatment.

  5. Aerosol extinction in coastal zone

    NARCIS (Netherlands)

    Piazzola, J.; Kaloshin, G.; Leeuw, G. de; Eijk, A.M.J. van

    2004-01-01

    The performance of electro-optical systems can be substantially affected by aerosol particles that scatter and absorb electromagnetic radiation. A few years ago, an empirical model was developed describing the aerosol size distributions in the Mediterranean coastal atmosphere near Toulon (France). T

  6. Aerosol therapy in young children

    NARCIS (Netherlands)

    H.M. Janssens (Hettie)

    2001-01-01

    textabstractInhalation of aerosolized drugs has become an established means for treatment of pulmonary diseases in the last fifiy years. The majoriry of aerosol therapy in childhood concerns inhaled corticosteroids and bronchodilators in the management of asthma. Administration of drugs via the inha

  7. Correlation for aerosol sedimentation

    International Nuclear Information System (INIS)

    The fission product source term from a postulated light water reactor (LWR) accident has several components. One of these components is the suspended aerosols present in the atmosphere during containment degradation and failure. Sedimentation, inertial impaction, and Stefan-Nusselt flows are the dominant natural removal mechanisms in the containment atmosphere for the majority of the postulated LWR severe accidents. The sedimentation correlation described was developed for conditions applicable to the primary coolant system and containment under severe accident conditions. The correlation exists as a result of a unique nondimensional mass concentration versus nondimensional particle volume

  8. Aerosols indirectly warm the Arctic

    Directory of Open Access Journals (Sweden)

    T. Mauritsen

    2010-07-01

    Full Text Available On average, airborne aerosol particles cool the Earth's surface directly by absorbing and scattering sunlight and indirectly by influencing cloud reflectivity, life time, thickness or extent. Here we show that over the central Arctic Ocean, where there is frequently a lack of aerosol particles upon which clouds may form, a small increase in aerosol loading may enhance cloudiness thereby likely causing a climatologically significant warming at the ice-covered Arctic surface. Under these low concentration conditions cloud droplets grow to drizzle sizes and fall, even in the absence of collisions and coalescence, thereby diminishing cloud water. Evidence from a case study suggests that interactions between aerosol, clouds and precipitation could be responsible for attaining the observed low aerosol concentrations.

  9. An Indigenously Developed Insecticidal Aerosol

    Directory of Open Access Journals (Sweden)

    R. N. Varma

    1969-10-01

    Full Text Available A total of 6 "Test" insecticidal aerosols (TA-I to VI indigenously produced were tested during the years 1966-67 as suitable replacements for imported aerosols.TA-I produced deep yellow staining and a yellowish spray mist. Its capacity was only 120 ml fluid. TA-III types II and III containing modified aerosol formulation with "Esso solvent 3245" and mineral turpentine oil (Burmah Shelland Freon 12 11 (all indigenouswere comparable to he "SRA" in insecticidial efficacy. The container was also manufactured in the country and it compared well with the "SRA" in construction, resistance against rough usage and mechanical function. They were both finally approved for introduction in the services as replacement for imported aerosols. TA-IV performed well in inscticidial assessment, but the aerosols formulation. TA-V and VI were similar to TA-III types II and III respectively.

  10. Atmospheric and aerosol chemistry

    International Nuclear Information System (INIS)

    This series presents critical reviews of the present position and future trends in modern chemical research. Short and concise reports on chemistry, each written by the world renowned experts. Still valid and useful after 5 or 10 years. More information as well as the electronic version of the whole content available at: springerlink.com. Christian George, Barbara D'Anna, Hartmut Herrmann, Christian Weller, Veronica Vaida, D. J. Donaldson, Thorsten Bartels-Rausch, Markus Ammann Emerging Areas in Atmospheric Photochemistry. Lisa Whalley, Daniel Stone, Dwayne Heard New Insights into the Tropospheric Oxidation of Isoprene: Combining Field Measurements, Laboratory Studies, Chemical Modelling and Quantum Theory. Neil M. Donahue, Allen L. Robinson, Erica R. Trump, Ilona Riipinen, Jesse H. Kroll Volatility and Aging of Atmospheric Organic Aerosol. P. A. Ariya, G. Kos, R. Mortazavi, E. D. Hudson, V. Kanthasamy, N. Eltouny, J. Sun, C. Wilde Bio-Organic Materials in the Atmosphere and Snow: Measurement and Characterization V. Faye McNeill, Neha Sareen, Allison N. Schwier Surface-Active Organics in Atmospheric Aerosols.

  11. The GRAPE aerosol retrieval algorithm

    Directory of Open Access Journals (Sweden)

    G. E. Thomas

    2009-11-01

    Full Text Available The aerosol component of the Oxford-Rutherford Aerosol and Cloud (ORAC combined cloud and aerosol retrieval scheme is described and the theoretical performance of the algorithm is analysed. ORAC is an optimal estimation retrieval scheme for deriving cloud and aerosol properties from measurements made by imaging satellite radiometers and, when applied to cloud free radiances, provides estimates of aerosol optical depth at a wavelength of 550 nm, aerosol effective radius and surface reflectance at 550 nm. The aerosol retrieval component of ORAC has several incarnations – this paper addresses the version which operates in conjunction with the cloud retrieval component of ORAC (described by Watts et al., 1998, as applied in producing the Global Retrieval of ATSR Cloud Parameters and Evaluation (GRAPE data-set.

    The algorithm is described in detail and its performance examined. This includes a discussion of errors resulting from the formulation of the forward model, sensitivity of the retrieval to the measurements and a priori constraints, and errors resulting from assumptions made about the atmospheric/surface state.

  12. Research on aerosol formation, aerosol behaviour, aerosol filtration, aerosol measurement techniques and sodium fires at the Laboratory for Aerosol Physics and Filter Technology at the Nuclear Research Center Karlsruhe

    International Nuclear Information System (INIS)

    The behaviour of aerosols in LMFBR plant systems is of great importance for a number of problems, both normal operational and accident kind. This paper covers the following: aerosol modelling for LMFBR containment systems; aerosol size spectrometry by laser light scattering; experimental facilities and experimental results concerned with aerosol release under accident conditions; filtration of sodium oxide aerosols by multilayer sand bed filters

  13. ParABS system in chromosome partitioning in the bacterium Myxococcus xanthus.

    Directory of Open Access Journals (Sweden)

    Antonio A Iniesta

    Full Text Available Chromosome segregation is an essential cellular function in eukaryotic and prokaryotic cells. The ParABS system is a fundamental player for a mitosis-like process in chromosome partitioning in many bacterial species. This work shows that the social bacterium Myxococcus xanthus also uses the ParABS system for chromosome segregation. Its large prokaryotic genome of 9.1 Mb contains 22 parS sequences near the origin of replication, and it is shown here that M. xanthus ParB binds preferentially to a consensus parS sequence in vitro. ParB and ParA are essential for cell viability in M. xanthus as in Caulobacter crescentus, but unlike in many other bacteria. Absence of ParB results in anucleate cells, chromosome segregation defects and loss of viability. Analysis of ParA subcellular localization shows that it clusters at the poles in all cells, and in some, in the DNA-free cell division plane between two chromosomal DNA masses. This ParA localization pattern depends on ParB but not on FtsZ. ParB inhibits the nonspecific interaction of ParA with DNA, and ParA colocalizes with chromosomal DNA only when ParB is depleted. The subcellular localization of ParB suggests a single ParB-parS complex localized at the edge of the nucleoid, next to a polar ParA cluster, with a second ParB-parS complex migrating after the replication of parS takes place to the opposite nucleoid edge, next to the other polar ParA cluster.

  14. Shipborne aerosol IR decoy modulated by laser

    Institute of Scientific and Technical Information of China (English)

    叶晓英; 吴刚; 邓盼; 范宁

    2004-01-01

    Working principles, features, current situation and future development of the aerosol IR decoys are summarized in this paper, and a new type aerosol IR decoy aerosol IR decoy modulated by laser is emphasized. The simulation results show that compared with the traditional IR decoys, the late-model aerosol IR decoy effectively enhances the capability of protecting targets and countermining IR guidance weapons. It is a new direction of aerosol IR decoys.

  15. Effect of aerosolization on subsequent bacterial survival.

    OpenAIRE

    Walter, M V; Marthi, B; Fieland, V P; Ganio, L M

    1990-01-01

    To determine whether aerosolization could impair bacterial survival, Pseudomonas syringae and Erwinia herbicola were aerosolized in a greenhouse, the aerosol was sampled at various distances from the site of release by using all-glass impingers, and bacterial survival was followed in the impingers for 6 h. Bacterial survival subsequent to aerosolization of P. syringae and E. herbicola was not impaired 1 m from the site of release. P. syringae aerosolized at 3 to 15 m from the site of release ...

  16. A fixed frequency aerosol albedometer.

    Science.gov (United States)

    Thompson, Jonathan E; Barta, Nick; Policarpio, Danielle; Duvall, Richard

    2008-02-01

    A new method for the measurement of aerosol single scatter albedo (omega) at 532 nm was developed. The method employs cavity ring-down spectroscopy (CRDS) for measurement of aerosol extinction coefficient (b(ext)) and an integrating sphere nephelometer for determination of aerosol scattering coefficient (b(scat)). A unique feature of this method is that the extinction and scattering measurements are conducted simultaneously, on the exact same sample volume. Limits of detection (3s) for the extinction and scattering channel were 0.61 Mm(-1) and 2.7 Mm(-1) respectively. PMID:18542299

  17. Instrumentation for tropospheric aerosol characterization

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Z.; Young, S.E.; Becker, C.H.; Coggiola, M.J. [SRI International, Menlo Park, CA (United States); Wollnik, H. [Giessen Univ. (Germany)

    1997-12-31

    A new instrument has been developed that determines the abundance, size distribution, and chemical composition of tropospheric and lower stratospheric aerosols with diameters down to 0.2 {mu}m. In addition to aerosol characterization, the instrument also monitors the chemical composition of the ambient gas. More than 25.000 aerosol particle mass spectra were recorded during the NASA-sponsored Subsonic Aircraft: Contrail and Cloud Effects Special Study (SUCCESS) field program using NASA`s DC-8 research aircraft. (author) 7 refs.

  18. eDPS Aerosol Collection

    Energy Technology Data Exchange (ETDEWEB)

    Venzie, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-13

    The eDPS Aerosol Collection project studies the fundamental physics of electrostatic aerosol collection for national security applications. The interpretation of aerosol data requires understanding and correcting for biases introduced from particle genesis through collection and analysis. The research and development undertaken in this project provides the basis for both the statistical correction of existing equipment and techniques; as well as, the development of new collectors and analytical techniques designed to minimize unwanted biases while improving the efficiency of locating and measuring individual particles of interest.

  19. Aerosol growth in Titan's ionosphere.

    Science.gov (United States)

    Lavvas, Panayotis; Yelle, Roger V; Koskinen, Tommi; Bazin, Axel; Vuitton, Véronique; Vigren, Erik; Galand, Marina; Wellbrock, Anne; Coates, Andrew J; Wahlund, Jan-Erik; Crary, Frank J; Snowden, Darci

    2013-02-19

    Photochemically produced aerosols are common among the atmospheres of our solar system and beyond. Observations and models have shown that photochemical aerosols have direct consequences on atmospheric properties as well as important astrobiological ramifications, but the mechanisms involved in their formation remain unclear. Here we show that the formation of aerosols in Titan's upper atmosphere is directly related to ion processes, and we provide a complete interpretation of observed mass spectra by the Cassini instruments from small to large masses. Because all planetary atmospheres possess ionospheres, we anticipate that the mechanisms identified here will be efficient in other environments as well, modulated by the chemical complexity of each atmosphere. PMID:23382231

  20. Identification des gaz combustibles par capteur catalytique

    OpenAIRE

    Rose, Gérard

    1995-01-01

    L'explosimètre est un instrument destiné à prévenir le risque d'inflammation d'un mélange d'air et de gaz en informant de la présence du gaz par une alarme, et en délivrant une mesure qu'il exprime en pourcentage de la limite inférieure d'explosivité du mélange (LIE). Il répond à tous les gaz et vapeurs combustibles, mais il ne donne une mesure juste que pour un seul d'entre-eux : celui pour lequel il a été étalonné. Cet inconvénient est sans conséquence si l'utilisateur identifie le gaz, car...

  1. Parálisis cerebral Cerebral palsy

    OpenAIRE

    Jorge Malagon Valdez

    2007-01-01

    El término parálisis cerebral (PC) engloba a un gran número de síndromes neurológicos clínicos, de etiología diversa. Estos síndromes se caracterizan por tener una sintomatología común: los trastornos motores. Algunos autores prefieren manejar términos como "encefalopatía fija", "encefalopatías no evolutivas". Se mencionan la utilidad de programas de intervención temprana y métodos especiales de rehabilitación, así como el manejo de las deficiencias asociadas como la epilepsia, deficiencia me...

  2. Taare Zameen Par and dyslexic savants.

    Science.gov (United States)

    Chakravarty, Ambar

    2009-04-01

    The film Taare Zameen Par (Stars upon the Ground) portrays the tormented life at school and at home of a child with dyslexia and his eventual success after his artistic talents are discovered by his art teacher at the boarding school. The film hints at a curious neurocognitive phenomenon of creativity in the midst of language disability, as exemplified in the lives of people like Leonardo da Vinci and Albert Einstein, both of whom demonstrated extraordinary creativity even though they were probably affected with developmental learning disorders. It has been hypothesized that a developmental delay in the dominant hemisphere most likely 'disinhibits' the nondominant parietal lobe, unmasking talents-artistic or otherwise-in some such individuals. It has been suggested that, in remedial training, children with learning disorders be encouraged to develop such hidden talents to full capacity, rather than be subjected to the usual overemphasis on the correction of the disturbed coded symbol operations. PMID:20142854

  3. Taare Zameen Par and dyslexic savants

    Directory of Open Access Journals (Sweden)

    Chakravarty Ambar

    2009-01-01

    Full Text Available The film Taare Zameen Par (Stars upon the Ground portrays the tormented life at school and at home of a child with dyslexia and his eventual success after his artistic talents are discovered by his art teacher at the boarding school. The film hints at a curious neurocognitive phenomenon of creativity in the midst of language disability, as exemplified in the lives of people like Leonardo da Vinci and Albert Einstein, both of whom demonstrated extraordinary creativity even though they were probably affected with developmental learning disorders. It has been hypothesized that a developmental delay in the dominant hemisphere most likely ′disinhibits′ the nondominant parietal lobe, unmasking talents-artistic or otherwise-in some such individuals. It has been suggested that, in remedial training, children with learning disorders be encouraged to develop such hidden talents to full capacity, rather than be subjected to the usual overemphasis on the correction of the disturbed coded symbol operations.

  4. Paris vu par Jaime Gil de Biedma

    OpenAIRE

    Massip, Estrella

    2013-01-01

    Le poème París, postal del cielo de l’écrivain barcelonais en langue castillane Jaime Gil de Biedma (1929-1990) laisse entendre une multiplicité de voix dont chacune nous communique une image de Paris. C’est la mémoire du « je » poétique qui filtre cette polyphonie. Le voyage dans le Paris réel qui est à l’origine du poème est aussi le voyage de Gil de Biedma lecteur dans le double littéraire de cette ville. Les rapports intertextuels avec les œuvres de Blas de Otero et de Baudelaire permette...

  5. Plasma suPAR is lowered by smoking cessation

    DEFF Research Database (Denmark)

    Eugen-Olsen, Jesper; Ladelund, Steen; Sørensen, Lars Tue

    2016-01-01

    46 never smokers (1·9 ng/mL (1·7-2·2)). In smokers randomized to smoking cessation, suPAR levels after 4 weeks of stopping were decreased and no longer significantly different from the never smokers values. SuPAR decreased in both those who received a placebo as well as nicotine patch. Interestingly...

  6. Aerosol Transmission of Filoviruses

    Directory of Open Access Journals (Sweden)

    Berhanu Mekibib

    2016-05-01

    Full Text Available Filoviruses have become a worldwide public health concern because of their potential for introductions into non-endemic countries through international travel and the international transport of infected animals or animal products. Since it was first identified in 1976, in the Democratic Republic of Congo (formerly Zaire and Sudan, the 2013–2015 western African Ebola virus disease (EVD outbreak is the largest, both by number of cases and geographical extension, and deadliest, recorded so far in medical history. The source of ebolaviruses for human index case(s in most outbreaks is presumptively associated with handling of bush meat or contact with fruit bats. Transmission among humans occurs easily when a person comes in contact with contaminated body fluids of patients, but our understanding of other transmission routes is still fragmentary. This review deals with the controversial issue of aerosol transmission of filoviruses.

  7. Aerosol Transmission of Filoviruses.

    Science.gov (United States)

    Mekibib, Berhanu; Ariën, Kevin K

    2016-01-01

    Filoviruses have become a worldwide public health concern because of their potential for introductions into non-endemic countries through international travel and the international transport of infected animals or animal products. Since it was first identified in 1976, in the Democratic Republic of Congo (formerly Zaire) and Sudan, the 2013-2015 western African Ebola virus disease (EVD) outbreak is the largest, both by number of cases and geographical extension, and deadliest, recorded so far in medical history. The source of ebolaviruses for human index case(s) in most outbreaks is presumptively associated with handling of bush meat or contact with fruit bats. Transmission among humans occurs easily when a person comes in contact with contaminated body fluids of patients, but our understanding of other transmission routes is still fragmentary. This review deals with the controversial issue of aerosol transmission of filoviruses. PMID:27223296

  8. Stratospheric aerosol geoengineering

    International Nuclear Information System (INIS)

    The Geoengineering Model Intercomparison Project, conducting climate model experiments with standard stratospheric aerosol injection scenarios, has found that insolation reduction could keep the global average temperature constant, but global average precipitation would reduce, particularly in summer monsoon regions around the world. Temperature changes would also not be uniform; the tropics would cool, but high latitudes would warm, with continuing, but reduced sea ice and ice sheet melting. Temperature extremes would still increase, but not as much as without geoengineering. If geoengineering were halted all at once, there would be rapid temperature and precipitation increases at 5–10 times the rates from gradual global warming. The prospect of geoengineering working may reduce the current drive toward reducing greenhouse gas emissions, and there are concerns about commercial or military control. Because geoengineering cannot safely address climate change, global efforts to reduce greenhouse gas emissions and to adapt are crucial to address anthropogenic global warming

  9. Identification of secondary organic aerosols based on aerosol mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Secondary organic aerosol (SOA) is one of the major components of aerosols in the atmosphere and has not been well understood so far.Due to the complex chemical composition of organic aerosols,the identification of SOA has been a hotspot and difficult issue in the field of aerosol study.This study attempts to quantitatively identify SOA in winter of Shenzhen based on positive matrix factorization (PMF) analysis.Major sources were resolved and SOA was identified subsequently according to the characteristic ion fragments measured by highly time-resolved aerosol mass spectrometer measurement.It showed that in the winter of Shenzhen the average SOA concentration was 9.41±6.33 g/m 3,accounting for 39.9±21.8% of the total organic mass.Compared with primary organic aerosol (POA),the SOA concentrations had no large variation,suggestive of characteristics of regional secondary pollutants.The ratio of SOA/BC had pronounced diurnal variation,similar to that of O x (O3+NO2),indicating SOA formation was significantly controlled by activity of photochemistry in the atmosphere.The most effective period for SOA formation was from 9 am~3 pm since the SOA/BC ratio increased by 122% during this period.This study provides a new technical method and a new idea for SOA investigation.

  10. Contribution a l'industrialisation du soudage par friction malaxage

    OpenAIRE

    Zimmer, Sandra

    2009-01-01

    Le soudage par friction malaxage, ou FSW, est un procédé de soudage à l'« état solide » permettant d'éviter certains problèmes rencontrés en soudage par fusion comme la fissuration à chaud ou la création de soufflures. La soudure est réalisée par l'action d'un outil à l'interface de deux pièces à souder. Celui-ci a pour rôle de malaxer et d'échauffer par frottement la matière. Le cordon est réalisé de proche en proche. Les efforts générés à l'interface outil/matière doivent être repris par la...

  11. ANISOTROPIE STRUCTURELLE INDUITE PAR L'ETIRAGE A CHAUD D'UNE PREFORME EN SILICE PURE – ETUDE PAR DYNAMIQUE MOLECULAIRE ET PAR SPECTROMETRIE RAMAN

    OpenAIRE

    Bidault, Xavier; Chaussedent, Stéphane; Blanc, Wilfried; R. Neuville, D.

    2014-01-01

    Cette étude révèle un nouvel aspect sur la structure de la silice à l'échelle nanométrique. L'orientation acquise par les petits anneaux (Si-O) n pour n ≤ 5 suite à la déformation à chaud persiste à froid et induit une anisotropie structurale dont la forme « isotropie transverse » est vérifiée par spectrométrie Raman.

  12. Recombination in the human Pseudoautosomal region PAR1.

    Directory of Open Access Journals (Sweden)

    Anjali G Hinch

    2014-07-01

    Full Text Available The pseudoautosomal region (PAR is a short region of homology between the mammalian X and Y chromosomes, which has undergone rapid evolution. A crossover in the PAR is essential for the proper disjunction of X and Y chromosomes in male meiosis, and PAR deletion results in male sterility. This leads the human PAR with the obligatory crossover, PAR1, to having an exceptionally high male crossover rate, which is 17-fold higher than the genome-wide average. However, the mechanism by which this obligatory crossover occurs remains unknown, as does the fine-scale positioning of crossovers across this region. Recent research in mice has suggested that crossovers in PAR may be mediated independently of the protein PRDM9, which localises virtually all crossovers in the autosomes. To investigate recombination in this region, we construct the most fine-scale genetic map containing directly observed crossovers to date using African-American pedigrees. We leverage recombination rates inferred from the breakdown of linkage disequilibrium in human populations and investigate the signatures of DNA evolution due to recombination. Further, we identify direct PRDM9 binding sites using ChIP-seq in human cells. Using these independent lines of evidence, we show that, in contrast with mouse, PRDM9 does localise peaks of recombination in the human PAR1. We find that recombination is a far more rapid and intense driver of sequence evolution in PAR1 than it is on the autosomes. We also show that PAR1 hotspot activities differ significantly among human populations. Finally, we find evidence that PAR1 hotspot positions have changed between human and chimpanzee, with no evidence of sharing among the hottest hotspots. We anticipate that the genetic maps built and validated in this work will aid research on this vital and fascinating region of the genome.

  13. Recombination in the human Pseudoautosomal region PAR1.

    Science.gov (United States)

    Hinch, Anjali G; Altemose, Nicolas; Noor, Nudrat; Donnelly, Peter; Myers, Simon R

    2014-07-01

    The pseudoautosomal region (PAR) is a short region of homology between the mammalian X and Y chromosomes, which has undergone rapid evolution. A crossover in the PAR is essential for the proper disjunction of X and Y chromosomes in male meiosis, and PAR deletion results in male sterility. This leads the human PAR with the obligatory crossover, PAR1, to having an exceptionally high male crossover rate, which is 17-fold higher than the genome-wide average. However, the mechanism by which this obligatory crossover occurs remains unknown, as does the fine-scale positioning of crossovers across this region. Recent research in mice has suggested that crossovers in PAR may be mediated independently of the protein PRDM9, which localises virtually all crossovers in the autosomes. To investigate recombination in this region, we construct the most fine-scale genetic map containing directly observed crossovers to date using African-American pedigrees. We leverage recombination rates inferred from the breakdown of linkage disequilibrium in human populations and investigate the signatures of DNA evolution due to recombination. Further, we identify direct PRDM9 binding sites using ChIP-seq in human cells. Using these independent lines of evidence, we show that, in contrast with mouse, PRDM9 does localise peaks of recombination in the human PAR1. We find that recombination is a far more rapid and intense driver of sequence evolution in PAR1 than it is on the autosomes. We also show that PAR1 hotspot activities differ significantly among human populations. Finally, we find evidence that PAR1 hotspot positions have changed between human and chimpanzee, with no evidence of sharing among the hottest hotspots. We anticipate that the genetic maps built and validated in this work will aid research on this vital and fascinating region of the genome. PMID:25033397

  14. Aerosol Size Distributions In Auckland.

    Czech Academy of Sciences Publication Activity Database

    Coulson, G.; Olivares, G.; Talbot, Nicholas

    2016-01-01

    Roč. 50, č. 1 (2016), s. 23-28. E-ISSN 1836-5876 Institutional support: RVO:67985858 Keywords : aerosol size distribution * particle number concentration * roadside Subject RIV: CF - Physical ; Theoretical Chemistry

  15. Aerosols Produced by Cosmic Rays

    DEFF Research Database (Denmark)

    Enghoff, Martin Andreas Bødker

    our investigation at the smallest scales, namely the role of cosmic ray produced ions on atmospheric aerosol nucleation and growth processes. Aerosol theory suggests that this is one of the most promising areas to search for an effect. However, guided by the nature of our initial results, it will be...... mechanism linking cosmic rays to clouds and climate is currently speculative, there have been various suggestions of the role atmospheric ions may play; these involve any one of a number of processes from the nucleation of aerosols up to the collection processes of cloud droplets. We have chosen to start...... applied to control the number of ions present. This will enable experiments to be performed both with and without the presence of ions, thus providing information as to the potential role of ions in aerosol processes....

  16. Highly Resolved Paleoclimatic Aerosol Records

    DEFF Research Database (Denmark)

    Kettner, Ernesto

    to paleotemperatures. Impurities in the matrix are comprised of particulate and soluble aerosols, each carrying information on its source’s activitiy and|or proximity. Opposed to gases and water isotopes, the seasonality of many aerosols is not smoothed out in the firn column so that large concentration gradients...... with frequently changing signs are preserved. Therefore, these aerosol records can be used for dating by annual layer counting. However, with increasing depth the annual layer thicknesses decreases due to pressure and ice flow and accurate dating is possible only as long as the rapid variations can be resolved...... experimentally. Over the last decades Continuous Flow Analysis (CFA) has become a well-established technique for aerosol quantification. In CFA, a piece of core is melted continuously and the melt water is analysed for an array of chemical impurities. When designing a CFA system, a trilemma between high sample...

  17. Effects of thrombin, PAR-1 activating peptide and a PAR-1 antagonist on umbilical artery resistance in vitro

    Directory of Open Access Journals (Sweden)

    Elliott John T

    2005-02-01

    Full Text Available Abstract Background The non-thrombotic effects of thrombin in cardiovascular tissues, as mediated via the protease activated receptors (PARs, and particularly PAR-1, have been the focus of much recent research. The aims of this study were to evaluate the effects of thrombin, a specific PAR-1 activating peptide (PAR1-AP, and a PAR-1 antagonist on human umbilical artery tone in vitro. Methods Human umbilical artery samples were obtained from 17 women at term. Arterial rings were suspended under physiologic conditions for isometric recording. The in vitro effects of thrombin (0.5 units/mL to 3 units/mL, PAR1-AP TFLLR-NH2 [10(-9 to 10(-6 M], and PAR-1 antagonist (N-trans cinnamoyl- p-fluoroPhe-p-guanidinoPhe-Leu-Arg-Orn-NH2 [10(-9 M to 10(-5 M] on umbilical artery tone were measured. Results Both thrombin and TFLLR-NH2 exerted a potent cumulative vasodilatory effect on human umbilical artery resistance (P 0.05. Conclusion These findings highlight a potential role for thrombin and PAR-1 receptors in vascular regulation of feto-placental blood flow in normal pregnancy, and in association with the vascular lesions associated with IUGR and pre-eclampsia.

  18. Effects of DTPA aerosol on lung contamination by lanthanum; Influence du DTPA en aerosol sur les contaminations pulmonaires au lanthane

    Energy Technology Data Exchange (ETDEWEB)

    Pasquier, C.; Voisin, D.; Thieblement, P.; Perrault, G.; Bayard, J. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1969-07-01

    Applying DTPA aerosol for the treatment of lung contamination by lanthanum we were able to determine its effectiveness as a function of time. Provided it was administered early during the two hours after exposure, over 50 per cent could be removed using lower therapeutic doses than those prescribed for other routes of administration. Its association with some enzymes did not enhance the chelator therapeutic effect. We also calculated the constant of passage of lanthanum through the alveolar wall and found a value of 0.016 mn{sup -1}. Finally, as we have discovered a large part cannot be mobilized by DTPA, we shall now study the physico-chemical mechanisms involved in this protection. (authors) [French] L'emploi du DTPA en aerosol dans le traitement des contaminations pulmonaires par le lanthane, nous a permis d'etablir et d'evaluer son efficacite en fonction du temps. A condition d'etre utilise precocement, dans les deux heures qui suivent la contamination, une fraction superieure a 50 pour cent peut etre eliminee et ceci avec des doses therapeutiques inferieures a celles preconisees pour les autres voies d'administration. L'association avec quelques autres enzymes n'a pas permis d'ameliorer l'effet therapeutique de ce chelateur. Nous avons egalement chiffre la constante de passage du lanthane a travers la barriere alveolaire dont la valeur est de l'ordre de 0.016 mn{sup -1} Enfin, la decouverte d'une importante partie non piegeable par le DTPA nous amene maintenant a etudier les mecanismes physico-chimiques de cette protection. (auteurs)

  19. Survival of bacteria during aerosolization.

    OpenAIRE

    Marthi, B; Fieland, V P; Walter, M.; Seidler, R J

    1990-01-01

    One form of commercial application of microorganisms, including genetically engineered microorganisms is as an aerosol. To study the effect of aerosol-induced stress on bacterial survival, nonrecombinant spontaneous antibiotic-resistant mutants of four organisms, Enterobacter cloacae, Erwinia herbicola, Klebsiella planticola, and Pseudomonas syringae, were sprayed in separate experiments in a greenhouse. Samples were collected over a distance of 15 m from the spray site for enumeration. Spore...

  20. The removal of sodium aerosols

    International Nuclear Information System (INIS)

    This paper is concentrated on the removal of sodium combustion aerosol. The experimental results are presented in it. Besides, the output of the aerosol, the igniting point and combustion rate of sodium are also obtained. An experimental device for removing of the aerosol consists of a blower, sodium combustion container, water-spraying column, water storage tank and nitrogen bottle. In order to compare the concentrations at the outlet of the column before and after the water-spraying, the concentration distribution was measured in the process of sodium burning. It was found that similar concentration could be obtained from sixth to eighth minute after ignition of sodium in the container. During the interval the water-spraying was performed, the measurement of the aerosol concentrations at different water-spray height was proceeded. The removing efficiency of the aerosol at different water-spraying heights is different. The efficiency at the height of 1220 mm is near to maximum. The results show that further increasing water-spray height could not greatly reduce the concentration of the aerosol at the outlet. (author)

  1. Comparison of sodium aerosol codes

    International Nuclear Information System (INIS)

    Although hypothetical fast reactor accidents leading to severe core damage are very low probability events, their consequences are to be assessed. During such accidents, one can envisage the ejection of sodium, mixed with fuel and fission products, from the primary circuit into the secondary containment. Aerosols can be formed either by mechanical dispersion of the molten material or as a result of combustion of the sodium in the mixture. Therefore considerable effort has been devoted to study the different sodium aerosol phenomena. To ensure that the problems of describing the physical behaviour of sodium aerosols were adequately understood, a comparison of the codes being developed to describe their behaviour was undertaken. The comparison consists of two parts. The first is a comparative study of the computer codes used to predict aerosol behaviour during a hypothetical accident. It is a critical review of documentation available. The second part is an exercise in which code users have run their own codes with a pre-arranged input. For the critical comparative review of the computer models, documentation has been made available on the following codes: AEROSIM (UK), MAEROS (USA), HAARM-3 (USA), AEROSOLS/A2 (France), AEROSOLS/B1 (France), and PARDISEKO-IIIb (FRG)

  2. Aerosol generation and delivery in medical applications

    International Nuclear Information System (INIS)

    It is well established that radioaerosol lung technique by inhalation is a very versatile technique in the evaluation of health effects and medical diagnostic applications, especially to detect chronic obstructive pulmonary diseases, their defence mechanism permeability and many others. Most important part of aerosol technology is to generate reproducibly stable diagnostic radioaerosols of known characteristics. Many compressed air atomisers are commercially available for generating aerosols but they have limited utility in aerosol inhalation, either because of large droplet size, low aerosol output or high airflow rates. There is clearly a need for a versatile and economical aerosol generation/inhalation system that can produce dry labelled aerosol particles with high deep lung delivery efficiency suitable for clinical studies. BARC (Bhabha Atomic Research Centre) has developed a dry aerosol generation/delivery system which operates on compressed air and generates dry polydisperse aerosols. This system is described along with an assessment of the aerosol characteristics and efficiency for diagnosis of various respiratory disorders

  3. Devices and methods for generating an aerosol

    KAUST Repository

    Bisetti, Fabrizio

    2016-03-03

    Aerosol generators and methods of generating aerosols are provided. The aerosol can be generated at a stagnation interface between a hot, wet stream and a cold, dry stream. The aerosol has the benefit that the properties of the aerosol can be precisely controlled. The stagnation interface can be generated, for example, by the opposed flow of the hot stream and the cold stream. The aerosol generator and the aerosol generation methods are capable of producing aerosols with precise particle sizes and a narrow size distribution. The properties of the aerosol can be controlled by controlling one or more of the stream temperatures, the saturation level of the hot stream, and the flow times of the streams.

  4. How important is organic aerosol hygroscopicity to aerosol indirect forcing?

    International Nuclear Information System (INIS)

    Organics are among the most abundant aerosol components in the atmosphere. However, there are still large uncertainties with emissions of primary organic aerosol (POA) and volatile organic compounds (VOCs) (precursor gases of secondary organic aerosol, SOA), formation of SOA, and chemical and physical properties (e.g., hygroscopicity) of POA and SOA. All these may have significant impacts on aerosol direct and indirect forcing estimated from global models. In this study a modal aerosol module (MAM) in the NCAR community atmospheric model (CAM) is used to examine sensitivities of aerosol indirect forcing to hygroscopicity (represented by a single parameter 'κ' ) of POA and SOA. Our model simulation indicates that in the present-day (PD) condition changing the 'κ' value of POA from 0 to 0.1 increases the number concentration of cloud condensational nuclei (CCN) at supersaturation S = 0.1% by 40-80% over the POA source regions, while changing the 'κ' value of SOA by ± 50% (from 0.14 to 0.07 and 0.21) changes the CCN concentration within 40%. There are disproportionally larger changes in CCN concentration in the pre-industrial (PI) condition. Due to the stronger impact of organics hygroscopicity on CCN and cloud droplet number concentration at PI condition, global annual mean anthropogenic aerosol indirect forcing (AIF) between PD and PI conditions reduces with the increase of the hygroscopicity of organics. Global annual mean AIF varies by 0.4 W m-2 in the sensitivity runs with the control run of - 1.3 W m-2, highlighting the need for improved understanding of organics hygroscopicity and its representation in global models.

  5. PARs for combustible gas control in advanced light water reactors

    International Nuclear Information System (INIS)

    This paper discusses the progress being made in the United States to introduce passive autocatalytic recombiner (PAR) technology as a cost-effective alternative to electric recombiners for controlling combustible gas produced in postulated accidents in both future Advanced Light Water Reactors (ALWRs) and certain U. S. operating nuclear plants. PARs catalytically recombine hydrogen and oxygen, gradually producing heat and water vapor. They have no moving parts and are self-starting and self-feeding, even under relatively cold and wet containment conditions. Buoyancy of the hot gases they create sets up natural convective flow that promotes mixing of combustible gases in a containment. In a non-inerted ALWR containment, two approaches each employing a combination of PARs and igniters are being considered to control hydrogen in design basis and severe accidents. In pre-inerted ALWRs, PARs alone control radiolytic oxygen produced in either accident type. The paper also discusses regulatory feedback regarding these combustible gas control approaches and describes a test program being conducted by the Electric Power Research Institute (EPRI) and Electricite de France (EdF) to supplement the existing PAR test database with performance data under conditions of interest to U.S. plants. Preliminary findings from the EPRI/EdF PAR model test program are included. Successful completion of this test program and confirmatory tests being sponsored by the U. S. NRC are expected to pave the way for use of PARs in ALWRs and operating plants. (author)

  6. The inflammatory marker suPAR after cardiac arrest

    DEFF Research Database (Denmark)

    Rundgren, Malin; Lyngbaek, Stig; Fisker, Helle; Friberg, Hans

    2015-01-01

    pilot study aimed at investigating suPAR levels in relation to outcome after CA and mild induced hypothermia. METHODS: suPAR levels were measured at 6, 36, and 72 hours in patients treated with hypothermia after CA. suPAR levels were analyzed in relation to survival after 6 months. Receiver operating...... characteristic curve (ROC)-analyses were performed, and area under the curve (AUC) was calculated. Time to return of spontaneous circulation (ROSC) was correlated to suPAR levels. RESULTS: Fifty-five patients (40 male, median 65 years) were included, and 33 (60%) were alive after 6 months. The suPAR levels were...... significantly higher in nonsurviving patients compared with survivors at 6 and 36 hours (p=0.006 and 0.034 respectively), but not at 72 hours. The suPAR levels increased from 6 to 72 hours (p<0.0001). Time to ROSC correlated positively with suPAR levels at 6 hours (p=0.003) but not at 36 and 72 hours. ROC...

  7. Rotational raman lidar for aerosol scattering coefficients

    International Nuclear Information System (INIS)

    Two channel lidar signals which are composed of the total rotational scattering and elastic signals provide good information for the aerosol scattering coefficients. We can calculate the aerosol backscattering coefficient and extinction coefficient directly without any assumption and calibration process. Generally, a high spectral resolution lidar is used for an aerosol monitoring. But we have designed a new normal spectral receiving lidar system which contains the scattering information simultaneously, and we have retrieved the aerosol scattering coefficient. The results show that there is no need to assume any relation between the aerosol backscattering and extinction and to consider any wavelength calibration process for the aerosol scattering coefficient

  8. PAR elevation influence on hydrogen floor layer depth

    International Nuclear Information System (INIS)

    In order to circumvent problems associated with containment loads resulting from a possible hydrogen combustion, French containments for instance are equipped with passive autocatalytic recombiners (PAR). The aim of this safety device is to recombine hydrogen with oxygen in order to limit hydrogen concentration. Hence, PAR distribution within the containment is a key feature to limit the hydrogen risk. According with the PARIS benchmark scenario and boundary conditions therein (EU-FP6, SARNET project) a floor layer developed with low mass and thermal mixing processes. In this paper we illustrate the link between the PAR elevation and the floor layer depth. (author)

  9. Endophthalmitis following pars plana vitrectomy for vitreous floaters

    Directory of Open Access Journals (Sweden)

    Henry CR

    2014-08-01

    Full Text Available Christopher R Henry, Stephen G Schwartz, Harry W Flynn Jr Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA Abstract: A case of Staphylococcus caprae endophthalmitis in a young patient following pars plana vitrectomy for symptomatic vitreous floaters is reported here. Recent literature suggests that there is an increasing trend of performing pars plana vitrectomy for symptomatic floaters. Although rare, the potential risk of endophthalmitis should be explicitly discussed with patients considering surgical intervention for vitreous floaters. Keywords: endophthalmitis, pars plana vitrectomy, vitreous floaters, floaterectomy, posterior vitreous detachment

  10. First-in-human uPAR PET

    DEFF Research Database (Denmark)

    Persson, Morten; Skovgaard, Dorthe; Brandt-Larsen, Malene;

    2015-01-01

    A first-in-human clinical trial with Positron Emission Tomography (PET) imaging of the urokinase-type plasminogen activator receptor (uPAR) in patients with breast, prostate and bladder cancer, is described. uPAR is expressed in many types of human cancers and the expression is predictive of....... The ligand exhibited good in vivo stability and fast clearance from plasma and tissue compartments by renal excretion. In addition, high uptake in both primary tumor lesions and lymph node metastases was seen and paralleled high uPAR expression in excised tumor tissue. Overall, this first-in-human...

  11. Formalisation d'annotations produites par des apprenants

    OpenAIRE

    Mille, Dominique

    2005-01-01

    L'objet de cet article est la description d'une formalisation computable des annotations produites par des apprenants, représentée par une ontologie. Cette formalisation explicite la sémantique des annotations grâce à des attributs auxquels le lecteur devrait donner une valeur. Elle contient également les valeurs possibles de ces attributs. L'intérêt d'une telle formalisation est de couvrir toutes les annotations produites par des apprenants, et d'expliciter tout ce qui constitue leur sens, a...

  12. Limnological database for Par Pond: 1959 to 1980

    International Nuclear Information System (INIS)

    A limnological database for Par Pond, a cooling reservoir for hot reactor effluent water at the Savannah River Plant, is described. The data are derived from a combination of research and monitoring efforts on Par Pond since 1959. The approximately 24,000-byte database provides water quality, primary productivity, and flow data from a number of different stations, depths, and times during the 22-year history of the Par Pond impoundment. The data have been organized to permit an interpretation of the effects of twenty years of cooling system operations on the structure and function of an aquatic ecosystem

  13. Effect of aerosol sub-grid variability on aerosol optical depth and cloud condensation nuclei: Implications for global aerosol modelling

    OpenAIRE

    Weigum, N; Schutgens, N.; Stier, P.

    2016-01-01

    A fundamental limitation of grid-based models is their inability to resolve variability on scales smaller than a grid box. Past research has shown that significant aerosol variability exists on scales smaller than these grid-boxes, which can lead to discrepancies in simulated aerosol climate effects between high and low resolution models. This study investigates the impact of neglecting sub-grid variability in present-day global microphysical aerosol models on aerosol optical depth (AOD) and ...

  14. Using the OMI aerosol index and absorption aerosol optical depth to evaluate the NASA MERRA Aerosol Reanalysis

    OpenAIRE

    Buchard, V.; A. M. Silva; P. R. Colarco; Darmenov, A.; C. A. Randles; Govindaraju, R.; O. Torres; Campbell, J.; R. Spurr

    2015-01-01

    A radiative transfer interface has been developed to simulate the UV aerosol index (AI) from the NASA Goddard Earth Observing System version 5 (GEOS-5) aerosol assimilated fields. The purpose of this work is to use the AI and aerosol absorption optical depth (AAOD) derived from the Ozone Monitoring Instrument (OMI) measurements as independent validation for the Modern Era Retrospective analysis for Research and Applications Aerosol Reanalysis (MERRAero). MERRAero is based on...

  15. Factors Affecting Aerosol Radiative Forcing

    Science.gov (United States)

    Wang, Jingxu; Lin, Jintai; Ni, Ruijing

    2016-04-01

    Rapid industrial and economic growth has meant a large amount of aerosols in the atmosphere with strong radiative forcing (RF) upon the climate system. Over parts of the globe, the negative forcing of aerosols has overcompensated for the positive forcing of greenhouse gases. Aerosol RF is determined by emissions and various chemical-transport-radiative processes in the atmosphere, a multi-factor problem whose individual contributors have not been well quantified. In this study, we analyze the major factors affecting RF of secondary inorganic aerosols (SIOAs, including sulfate, nitrate and ammonium), primary organic aerosol (POA), and black carbon (BC). We analyze the RF of aerosols produced by 11 major regions across the globe, including but not limited to East Asia, Southeast Asia, South Asia, North America, and Western Europe. Factors analyzed include population size, per capita gross domestic production (GDP), emission intensity (i.e., emissions per unit GDP), chemical efficiency (i.e., mass per unit emissions) and radiative efficiency (i.e., RF per unit mass). We find that among the 11 regions, East Asia produces the largest emissions and aerosol RF, due to relatively high emission intensity and a tremendous population size. South Asia produce the second largest RF of SIOA and BC and the highest RF of POA, in part due to its highest chemical efficiency among all regions. Although Southeast Asia also has large emissions, its aerosol RF is alleviated by its lowest chemical efficiency. The chemical efficiency and radiative efficiency of BC produced by the Middle East-North Africa are the highest across the regions, whereas its RF is lowered by a small per capita GDP. Both North America and Western Europe have low emission intensity, compensating for the effects on RF of large population sizes and per capita GDP. There has been a momentum to transfer industries to Southeast Asia and South Asia, and such transition is expected to continue in the coming years. The

  16. PAR1- and PAR2-induced innate immune markers are negatively regulated by PI3K/Akt signaling pathway in oral keratinocytes

    Directory of Open Access Journals (Sweden)

    Dale Beverly A

    2010-10-01

    Full Text Available Abstract Background Protease-Activated Receptors (PARs, members of G-protein-coupled receptors, are activated by proteolytic activity of various proteases. Activation of PAR1 and PAR2 triggers innate immune responses in human oral keratinocytes (HOKs, but the signaling pathways downstream of PAR activation in HOKs have not been clearly defined. In this study, we aimed to determine if PAR1- and PAR2-mediated signaling differs in the induction of innate immune markers CXCL3, CXCL5 and CCL20 via ERK, p38 and PI3K/Akt. Results Our data show the induction of innate immunity by PAR1 requires both p38 and ERK MAP kinases, while PAR2 prominently signals via p38. However, inhibition of PI3K enhances expression of innate immune markers predominantly via suppressing p38 phosphorylation signaled by PAR activation. Conclusion Our data indicate that proteases mediating PAR1 and PAR2 activation differentially signal via MAP kinase cascades. In addition, the production of chemokines induced by PAR1 and PAR2 is suppressed by PI3K/Akt, thus keeping the innate immune responses of HOK in balance. The results of our study provide a novel insight into signaling pathways involved in PAR activation.

  17. Direct radiative forcing of aerosols over a typical tropical urban environment

    International Nuclear Information System (INIS)

    Aerosols reduce the surface reaching solar flux by scattering the incoming solar radiation out to space. Various model studies on climate change suggest that surface cooling induced by aerosol scattering is the largest source of uncertainty in predicting the future climate. In the present study measurements of aerosol optical depth (AOD) and its direct radiative forcing efficiency has been presented over a typical tropical urban environment namely Hyderabad during 2001 and 2002. Diurnal variation of AOD suggesting that AOD is high during afternoon hours. AOD decreases with increase in wavelength, i.e. maximum AOD observed at 380 nm. Average monthly variation of AOD at different wavelengths observed to be minimum in January, moderately high in February to March, maximum in April and decreasing in May. AOD has been observed to be high during 2002 compared to 2001. AOD showed positive correlation with air temperature and negative correlation with rainfall. A statistical fit between AOD (500 nm) and photosynthetic active radiation (PAR which is in the range of 400-700 nm solar spectrum) shows negative correlation. The present study suggests -23 W m-2 reduction in the ground reaching solar flux for every 0.1 increase in aerosol optical depth over the study area. (author)

  18. Miniature Sensor for Aerosol Mass Measurements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR project seeks to develop a miniature sensor for mass measurement of size-classified aerosols. A cascade impactor will be used to classify aerosol sample...

  19. MISR Aerosol Climatology Product V001

    Data.gov (United States)

    National Aeronautics and Space Administration — This product is 1)the microphysical and scattering characteristics of pure aerosol upon which routine retrievals are based;2)mixtures of pure aerosol to be compared...

  20. Aerosol Climate Time Series in ESA Aerosol_cci

    Science.gov (United States)

    Popp, Thomas; de Leeuw, Gerrit; Pinnock, Simon

    2016-04-01

    Within the ESA Climate Change Initiative (CCI) Aerosol_cci (2010 - 2017) conducts intensive work to improve algorithms for the retrieval of aerosol information from European sensors. Meanwhile, full mission time series of 2 GCOS-required aerosol parameters are completely validated and released: Aerosol Optical Depth (AOD) from dual view ATSR-2 / AATSR radiometers (3 algorithms, 1995 - 2012), and stratospheric extinction profiles from star occultation GOMOS spectrometer (2002 - 2012). Additionally, a 35-year multi-sensor time series of the qualitative Absorbing Aerosol Index (AAI) together with sensitivity information and an AAI model simulator is available. Complementary aerosol properties requested by GCOS are in a "round robin" phase, where various algorithms are inter-compared: fine mode AOD, mineral dust AOD (from the thermal IASI spectrometer, but also from ATSR instruments and the POLDER sensor), absorption information and aerosol layer height. As a quasi-reference for validation in few selected regions with sparse ground-based observations the multi-pixel GRASP algorithm for the POLDER instrument is used. Validation of first dataset versions (vs. AERONET, MAN) and inter-comparison to other satellite datasets (MODIS, MISR, SeaWIFS) proved the high quality of the available datasets comparable to other satellite retrievals and revealed needs for algorithm improvement (for example for higher AOD values) which were taken into account for a reprocessing. The datasets contain pixel level uncertainty estimates which were also validated and improved in the reprocessing. For the three ATSR algorithms the use of an ensemble method was tested. The paper will summarize and discuss the status of dataset reprocessing and validation. The focus will be on the ATSR, GOMOS and IASI datasets. Pixel level uncertainties validation will be summarized and discussed including unknown components and their potential usefulness and limitations. Opportunities for time series extension

  1. Récolte et consommation de pollen par les abeilles

    OpenAIRE

    Odoux, Jean Francois

    2005-01-01

    La récolte de pollen par les abeilles fait appel à des organes spécialisés de l'abeille, comme celle du nectar. Par contre, elle est régie par de très nombreux facteurs, en fonction des ressources, bien sûr, mais aussi des besoins de la colonie, alors que son attractivité n'est pas toujours en rapport avec la qualité. Ce texte décrit le contexte de l'utilisation du pollen par les abeilles, de la récolte à la digestion, d'après une synthèse bibliographique.

  2. La preuve apportée par les sciences

    Directory of Open Access Journals (Sweden)

    1997-04-01

    Full Text Available A propos d´une enquête menée par deux immunologistes de l´Université de Göteborg, rapportée par la très sérieuse revue Nature, le journal Le Monde n´hésitait pas à titrer : " La preuve du sexisme apportée par les sciences ". Les auteurs avaient en effet pu démontrer, irréfutables tests statistiques à l´appui, que, pour obtenir une bourse de post-doctorat offerte par le Swedisch Medical Research Council, les femmes devaient être deux fois et demie plus productives que les hommes ! Nous voulons...

  3. A turquesa de Itacupim, Pará

    Directory of Open Access Journals (Sweden)

    Marcondes Lima da Costa

    2004-12-01

    Full Text Available Na ilha de Itacupim, localizada na região costeira do nordeste do Pará, foram encontrados veios de fosfatos de alumínio contendo turquesa, além de quartzo e argilominerais. A ilha é sustentada por espesso perfil laterítico maturo desenvolvido sobre complexo alcalino-ultramáfico mineralizado em apatita. Os veios e vênulas são de espessura centimétrica, normalmente constituídos de wavellita fibro-radial, onde pode ser observada turquesa verde-azulada, em massas subesferolíticas, microcristalinas, intercrescidas com caulinita e oxi-hidróxidos de Mn, além de quartzo. A identificação mineral foi realizada por DRX, microscopia óptica, análises químicas de rocha total, MEV/SED. Os teores de CuO são inferiores aos das turquesas em geral, compensados por Fe2O3 e ZnO. Os subesferolitos de turquesa contêm inúmeras inclusões micrométricas de goyazita ou svanbergita. A ocorrência da turquesa, na forma de veios e vênulas, seu aspecto porcelanado e a conhecida relação desse mineral com ambiente hidrotermal sugerem que a turquesa de Itacupim também seja de origem hidrotermal, reforçada pela sua associação com wavellita, goyazita ou svanbergita, quartzo e argilominerais. Ela não foi encontrada no perfil laterítico. Seu aspecto compacto e sua cor esverdeada abrem perspectivas para seu uso como mineral de gema.Veins and veinlets of aluminum phosphates with turquoise occur at the Itacupim Island in the coastal plain northeast the state of Pará. A thick mature lateritic iron crust rich in aluminum phosphates developed an apatite-bearing alkaline-ultramafic complex which constitutes the Island. The veins and veinlets are cm-thick, usually constituted by wavellite, fibrous to radialfibrous, with bony or porcelaneous aspect, and can turquoise. Pebbles of these phosphates inside of apatite-bearing ultramafic rocks are very common at the base of the hang wall, and locally form expressive agglomerates. Turquoise forms half spheroids and

  4. Aerosol MALDI mass spectrometry for bioaerosol analysis

    OpenAIRE

    Kleefsman, W.A.

    2008-01-01

    In the thesis Aerosol MALDI mass spectrometry for bioaerosol analysis is described how the aerosol mass spectrometer of the TU Delft has been further developed for the on-line analysis of bioaerosols. Due to the implemented improvements mass spectra with high resolution and a high mass range can be obtained from single protein containing aerosol particles. Fluorescence is used to select the biological fraction of an aerosol: when a particle emits fluorescence when irradiated with UV-laser lig...

  5. Origins of atmospheric aerosols. Basic concepts on aerosol main physical properties; L`aerosol atmospherique: ses origines quelques notions sur les principales proprietes physiques des aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Renoux, A. [Paris-12 Univ., 94 - Creteil (France). Laboratoire de Physique des aerosols et de transferts des contaminations

    1996-12-31

    Natural and anthropogenic sources of atmospheric aerosols are reviewed and indications of their concentrations and granulometry are given. Calculation of the lifetime of an atmospheric aerosol of a certain size is presented and the various modes of aerosol granulometry and their relations with photochemical and physico-chemical processes in the atmosphere are discussed. The main physical, electrical and optical properties of aerosols are also presented: diffusion coefficient, dynamic mobility and relaxation time, Stokes number, limit rate of fall, electrical mobility, optical diffraction

  6. Natural aerosol direct and indirect radiative effects

    OpenAIRE

    Rap, Alexandru; Scott, Catherine E.; Spracklen, Dominick V; Bellouin, Nicolas; Forster, Piers M.; Carslaw, Kenneth S.; Schmidt, Anja; Mann, Graham

    2013-01-01

    Natural aerosol plays a significant role in the Earth's system due to its ability to alter the radiative balance of the Earth. Here we use a global aerosol microphysics model together with a radiative transfer model to estimate radiative effects for five natural aerosol sources in the present-day atmosphere: dimethyl sulfide (DMS), sea-salt, volcanoes, monoterpenes, and wildfires. We calculate large annual global mean aerosol direct and cloud albedo effects especially for DMS-derived sulfate ...

  7. Aerosol filtration with metallic fibrous filters

    International Nuclear Information System (INIS)

    The filtration efficiency of stainless steel fibrous filters (BEKIPOR porous mats and sintered webs) is determined using submicronic monodisperse polystyrene aerosols. Lasers spectrometers are used for the aerosol measurements. The parameters varied are the fiber diameter, the number of layers, the aerosol diameter and the superficial velocity. Two selected types of filters are tested with polydisperse methylene blue aerosols to determine the effect of bed loading on the filter performance and to test washing techniques for the regeneration of the filter

  8. Parálisis cerebral Cerebral palsy

    Directory of Open Access Journals (Sweden)

    Jorge Malagon Valdez

    2007-01-01

    Full Text Available El término parálisis cerebral (PC engloba a un gran número de síndromes neurológicos clínicos, de etiología diversa. Estos síndromes se caracterizan por tener una sintomatología común: los trastornos motores. Algunos autores prefieren manejar términos como "encefalopatía fija", "encefalopatías no evolutivas". Se mencionan la utilidad de programas de intervención temprana y métodos especiales de rehabilitación, así como el manejo de las deficiencias asociadas como la epilepsia, deficiencia mental, trastornos del lenguaje, audición, visión, déficit de la atención que mejoran el pronóstico de manera significativa. El pronóstico también depende de la gravedad del padecimiento y de las manifestaciones asociadas.The term cerebral palsy (CP, is used for a great number of clinical neurological syndromes. The syndromes are characterized by having a common cause, motor defects. It is important, because they can cause a brain damage by presenting motor defects and some associated deficiencies, such as mental deficiency, epilepsy, language and visual defects and pseudobulbar paralysis, with the nonevolving fact. Some authors prefer using terms such as "non-evolving encephalopathies". In the treatment the utility of prevention programs of early stimulation and special rehabilitation methods, and treatment of associated deficiencies such as epilepsy, mental deficiency, language, audition and visual problems, and the attention deficit improve the prognosis in an important way. The prognosis depends on the severity of the disease and the associated manifestations.

  9. Aerosol retrieval experiments in the ESA Aerosol_cci project

    Directory of Open Access Journals (Sweden)

    T. Holzer-Popp

    2013-08-01

    Full Text Available Within the ESA Climate Change Initiative (CCI project Aerosol_cci (2010–2013, algorithms for the production of long-term total column aerosol optical depth (AOD datasets from European Earth Observation sensors are developed. Starting with eight existing pre-cursor algorithms three analysis steps are conducted to improve and qualify the algorithms: (1 a series of experiments applied to one month of global data to understand several major sensitivities to assumptions needed due to the ill-posed nature of the underlying inversion problem, (2 a round robin exercise of "best" versions of each of these algorithms (defined using the step 1 outcome applied to four months of global data to identify mature algorithms, and (3 a comprehensive validation exercise applied to one complete year of global data produced by the algorithms selected as mature based on the round robin exercise. The algorithms tested included four using AATSR, three using MERIS and one using PARASOL. This paper summarizes the first step. Three experiments were conducted to assess the potential impact of major assumptions in the various aerosol retrieval algorithms. In the first experiment a common set of four aerosol components was used to provide all algorithms with the same assumptions. The second experiment introduced an aerosol property climatology, derived from a combination of model and sun photometer observations, as a priori information in the retrievals on the occurrence of the common aerosol components. The third experiment assessed the impact of using a common nadir cloud mask for AATSR and MERIS algorithms in order to characterize the sensitivity to remaining cloud contamination in the retrievals against the baseline dataset versions. The impact of the algorithm changes was assessed for one month (September 2008 of data: qualitatively by inspection of monthly mean AOD maps and quantitatively by comparing daily gridded satellite data against daily averaged AERONET sun

  10. Aerosols and fission product transport

    International Nuclear Information System (INIS)

    A survey is presented of current knowledge of the possible role of aerosols in the consequences of in- and out-of-core LOCAs and of end fitting failures in CANDU reactors. An extensive literature search has been made of research on the behaviour of aerosols in possible accidents in water moderated and cooled reactors and the results of various studies compared. It is recommended that further work should be undertaken on the formation of aerosols during these possible accidents and to study their subsequent behaviour. It is also recommended that the fission products behaviour computer code FISSCON II should be re-examined to determine whether it reflects the advances incorporated in other codes developed for light water reactors which have been extensively compared. 47 refs

  11. Air ions and aerosol science

    Science.gov (United States)

    Tammet, Hannes

    1996-03-01

    Collaboration between Gas Discharge and Plasma Physics, Atmospheric Electricity, and Aerosol Science is a factor of success in the research of air ions. The concept of air ion as of any carrier of electrical current through the air is inherent to Atmospheric Electricity under which a considerable statistical information about the air ion mobility spectrum is collected. A new model of air ion size-mobility correlation has been developed proceeding from Aerosol Science and joining the methods of neighboring research fields. The predicted temperature variation of the mobility disagrees with the commonly used Langevin rule for the reduction of air ion mobilities to the standard conditions. Concurrent errors are too big to be neglected in applications. The critical diameter distinguishing cluster ions and charged aerosol particles has been estimated to be 1.4-1.8 nm.

  12. Air ions and aerosol science

    Energy Technology Data Exchange (ETDEWEB)

    Tammet, H. [Department of Environmental Physics, Tartu University, Tartu, Estonia (Estonia) 2400

    1996-03-01

    Collaboration between Gas Discharge and Plasma Physics, Atmospheric Electricity, and Aerosol Science is a factor of success in the research of air ions. The concept of air ion as of any carrier of electrical current through the air is inherent to Atmospheric Electricity under which a considerable statistical information about the air ion mobility spectrum is collected. A new model of air ion size-mobility correlation has been developed proceeding from Aerosol Science and joining the methods of neighboring research fields. The predicted temperature variation of the mobility disagrees with the commonly used Langevin rule for the reduction of air ion mobilities to the standard conditions. Concurrent errors are too big to be neglected in applications. The critical diameter distinguishing cluster ions and charged aerosol particles has been estimated to be 1.4{endash}1.8 nm. {copyright} {ital 1996 American Institute of Physics.}

  13. Characterization of Florida red tide aerosol and the temporal profile of aerosol concentration

    OpenAIRE

    Cheng, Yung Sung; Zhou, Yue; Pierce, Richard H.; Henry, Mike; Baden, Daniel G.

    2009-01-01

    Red tide aerosols containing aerosolized brevetoxins are produced during the red tide bloom and transported by wind to coastal areas of Florida. This study reports the characterization of Florida red tide aerosols in human volunteer studies, in which an asthma cohort spent 1 h on Siesta Beach (Sarasota, Florida) during aerosolized red tide events and non-exposure periods. Aerosol concentrations, brevetoxin levels, and particle size distribution were measured. Hourly filter samples were taken ...

  14. The relationship between aerosol and cloud drop number concentrations in a global aerosol microphysics model

    OpenAIRE

    Pringle, K. J.; Carslaw, K. S.; D. V. Spracklen; Mann, G. M.; M. P. Chipperfield

    2009-01-01

    Empirical relationships that link cloud droplet number (CDN) to aerosol number or mass are commonly used to calculate global fields of CDN for climate forcing assessments. In this work we use a sectional global model of sulfate and sea-salt aerosol coupled to a mechanistic aerosol activation scheme to explore the limitations of this approach. We find that a given aerosol number concentration produces a wide range of CDN concentrations due to variations in the shape of the aerosol size distrib...

  15. ATI TDA 5A aerosol generator evaluation

    International Nuclear Information System (INIS)

    Oil based aerosol ''Smoke'' commonly used for testing the efficiency and penetration of High Efficiency Particulate Air filters (HEPA) and HEPA systems can produce flammability hazards that may not have been previously considered. A combustion incident involving an aerosol generator has caused an investigation into the hazards of the aerosol used to test HEPA systems at Hanford

  16. Croissance epitaxiale de GaAs sur substrats de Ge par epitaxie par faisceaux chimiques

    Science.gov (United States)

    Belanger, Simon

    La situation energetique et les enjeux environnementaux auxquels la societe est confrontee entrainent un interet grandissant pour la production d'electricite a partir de l'energie solaire. Parmi les technologies actuellement disponibles, la filiere du photovoltaique a concentrateur solaire (CPV pour concentrator photovoltaics) possede un rendement superieur et mi potentiel interessant a condition que ses couts de production soient competitifs. La methode d'epitaxie par faisceaux chimiques (CBE pour chemical beam epitaxy) possede plusieurs caracteristiques qui la rendent interessante pour la production a grande echelle de cellules photovoltaiques a jonctions multiples a base de semi-conducteurs III-V. Ce type de cellule possede la meilleure efficacite atteinte a ce jour et est utilise sur les satellites et les systemes photovoltaiques a concentrateur solaire (CPV) les plus efficaces. Une des principales forces de la technique CBE se trouve dans son potentiel d'efficacite d'utilisation des materiaux source qui est superieur a celui de la technique d'epitaxie qui est couramment utilisee pour la production a grande echelle de ces cellules. Ce memoire de maitrise presente les travaux effectues dans le but d'evaluer le potentiel de la technique CBE pour realiser la croissance de couches de GaAs sur des substrats de Ge. Cette croissance constitue la premiere etape de fabrication de nombreux modeles de cellules solaires a haute performance decrites plus haut. La realisation de ce projet a necessite le developpement d'un procede de preparation de surface pour les substrats de germanium, la realisation de nombreuses sceances de croissance epitaxiale et la caracterisation des materiaux obtenus par microscopie optique, microscopie a force atomique (AFM), diffraction des rayons-X a haute resolution (HRXRD), microscopie electronique a transmission (TEM), photoluminescence a basse temperature (LTPL) et spectrometrie de masse des ions secondaires (SIMS). Les experiences ont permis

  17. Aerosol Transport Over Equatorial Africa

    Science.gov (United States)

    Gatebe, C. K.; Tyson, P. D.; Annegarn, H. J.; Kinyua, A. M.; Piketh, S.; King, M.; Helas, G.

    1999-01-01

    Long-range and inter-hemispheric transport of atmospheric aerosols over equatorial Africa has received little attention so far. Most aerosol studies in the region have focussed on emissions from rain forest and savanna (both natural and biomass burning) and were carried out in the framework of programs such as DECAFE (Dynamique et Chimie Atmospherique en Foret Equatoriale) and FOS (Fires of Savanna). Considering the importance of this topic, aerosols samples were measured in different seasons at 4420 meters on Mt Kenya and on the equator. The study is based on continuous aerosol sampling on a two stage (fine and coarse) streaker sampler and elemental analysis by Particle Induced X-ray Emission. Continuous samples were collected for two seasons coinciding with late austral winter and early austral spring of 1997 and austral summer of 1998. Source area identification is by trajectory analysis and sources types by statistical techniques. Major meridional transports of material are observed with fine-fraction silicon (31 to 68 %) in aeolian dust and anthropogenic sulfur (9 to 18 %) being the major constituents of the total aerosol loading for the two seasons. Marine aerosol chlorine (4 to 6 %), potassium (3 to 5 %) and iron (1 to 2 %) make up the important components of the total material transport over Kenya. Minimum sulfur fluxes are associated with recirculation of sulfur-free air over equatorial Africa, while maximum sulfur concentrations are observed following passage over the industrial heartland of South Africa or transport over the Zambian/Congo Copperbelt. Chlorine is advected from the ocean and is accompanied by aeolian dust recirculating back to land from mid-oceanic regions. Biomass burning products are transported from the horn of Africa. Mineral dust from the Sahara is transported towards the Far East and then transported back within equatorial easterlies to Mt Kenya. This was observed during austral summer and coincided with the dying phase of 1997/98 El

  18. Evaluation of atmospheric aerosol and tropospheric ozone effects on global terrestrial ecosystem carbon dynamics

    Science.gov (United States)

    Chen, Min

    The increasing human activities have produced large amounts of air pollutants ejected into the atmosphere, in which atmospheric aerosols and tropospheric ozone are considered to be especially important because of their negative impacts on human health and their impacts on global climate through either their direct radiative effect or indirect effect on land-atmosphere CO2 exchange. This dissertation dedicates to quantifying and evaluating the aerosol and tropospheric ozone effects on global terrestrial ecosystem dynamics using a modeling approach. An ecosystem model, the integrated Terrestrial Ecosystem Model (iTem), is developed to simulate biophysical and biogeochemical processes in terrestrial ecosystems. A two-broad-band atmospheric radiative transfer model together with the Moderate-Resolution Imaging Spectroradiometer (MODIS) measured atmospheric parameters are used to well estimate global downward solar radiation and the direct and diffuse components in comparison with observations. The atmospheric radiative transfer modeling framework were used to quantify the aerosol direct radiative effect, showing that aerosol loadings cause 18.7 and 12.8 W m -2 decrease of direct-beam Photosynthetic Active Radiation (PAR) and Near Infrared Radiation (NIR) respectively, and 5.2 and 4.4 W m -2 increase of diffuse PAR and NIR, respectively, leading to a total 21.9 W m-2 decrease of total downward solar radiation over the global land surface during the period of 2003-2010. The results also suggested that the aerosol effect may be overwhelmed by clouds because of the stronger extinction and scattering ability of clouds. Applications of the iTem with solar radiation data and with or without considering the aerosol loadings shows that aerosol loading enhances the terrestrial productions [Gross Primary Production (GPP), Net Primary Production (NPP) and Net Ecosystem Production (NEP)] and carbon emissions through plant respiration (RA) in global terrestrial ecosystems over the

  19. The urokinase receptor (uPAR) and the uPAR-associated protein (uPARAP/Endo180)

    DEFF Research Database (Denmark)

    Behrendt, Niels

    2004-01-01

    processes involve a highly organized interplay between proteases and their cellular binding sites as well as specific substrates and internalization receptors. This review article is focused on two components, the urokinase plasminogen activator receptor (uPAR) and the uPAR-associated protein (uPARAP, also......The breakdown of the barriers formed by extracellular matrix proteins is a pre-requisite for all processes of tissue remodeling. Matrix degradation reactions take part in specific physiological events in the healthy organism but also represent a crucial step in cancer invasion. These degradation...... designated Endo180), that are considered crucially engaged in matrix degradation. uPAR and uPARAP have highly diverse functions, but on certain cell types they interact with each other in a process that is still incompletely understood. uPAR is a glycosyl-phosphatidylinositol-anchored glycoprotein on the...

  20. The coagulation of radioactive aerosols

    International Nuclear Information System (INIS)

    Radioactive aerosols can become charged by emitting charges during the decay process, and the resulting electrostatic forces will modify coagulation rates. For Brownian coagulation, calculations for nuclear containment aerosols show that rates averaged over charge distributions can be strongly reduced between particles of the same size, but that increases in average rates can occur for particles of different sizes. The increases arise from small, but significant, negative charging of non-radioactive and small-sized radioactive particles, and are sensitive to the asymmetry between the positive and negative ion mobilities. (Author)

  1. Aerosols of Mongolian arid area

    Science.gov (United States)

    Golobokova, L.; Marinayte, I.; Zhamsueva, G.

    2012-04-01

    Sampling was performed in July-August 2005-2010 at Station Sain Shand (44°54'N, 110°07'E) in the Gobi desert (1000 m a.s.l.), West Mongolia. Aerosol samples were collected with a high volume sampler PM 10 (Andersen Instruments Inc., USA) onto Whatman-41 filters. The substance was extracted from the filters by de-ionized water. The solution was screened through an acetate-cellulose filter with 0.2 micron pore size. Ions of ammonium, sodium, potassium, magnesium, and calcium, as well as sulphate ions, nitrate ions, hydrocarbonate, chloride ions were determined in the filtrate by means of an atomic adsorption spectrometer Carl Zeiss Jena (Germany), a high performance liquid chromatographer «Milichrome A-02» (Russia), and an ionic chromatographer ICS-3000 (Dionex, USA). The PAH fraction was separated from aerosol samples using hexane extraction at room temperature under UV environment. The extract was concentrated to 0.1-0.2 ml and analysed by a mass-spectrometer "Agilent, GC 6890, MSD 5973 Network". Analysis of concentrations of aerosols components, their correlation ratios, and meteorological modeling show that the main factor affecting chemical composition of aerosols is a flow of contaminants transferred by air masses to the sampling area mainly from the south and south-east, as well as wind conditions of the area, dust storms in particular. Sulphate, nitrate, and ammonium are major ions in aerosol particles at Station Sain Shand. Dust-borne aerosol is known to be a sorbent for both mineral and organic admixtures. Polycyclic aromatic hydrocarbons (PAH) being among superecotoxicants play an important role among resistant organic substances. PAH concentrations were determined in the samples collected in 2010. All aerosol samples contained dominant PAHs with 5-6 benzene rings ( (benze(k)fluoranthen, benze(b)flouranthen, benze(a)pyren, benze(?)pyren, perylene, benze(g,h,i)perylene, and indene(1,2,3-c,d)pyrene). Their total quantity varied between 42 and 90

  2. Dissolution of LMFBR fuel-sodium aerosols

    International Nuclear Information System (INIS)

    Aerosols of either LMFBR fuel or PuO2 are essentially insoluble in water or biological fluids. If either of these aerosols is exposed to sodium metal vapor, the resulting aerosol is much more soluble in aqueous solutions. Preferential dissolution of uranium from mixed sodium-fuel aerosols makes the plutonium more readily soluble than for sodium-PuO2 aerosol. Ultrafiltration of the dissolution test solvent revealed the plutonium to be associated with particles between 2 nm and 10 nm in diameter, in both cases

  3. Contribution of methane to aerosol carbon mass

    Science.gov (United States)

    Bianchi, F.; Barmet, P.; Stirnweis, L.; El Haddad, I.; Platt, S. M.; Saurer, M.; Lötscher, C.; Siegwolf, R.; Bigi, A.; Hoyle, C. R.; DeCarlo, P. F.; Slowik, J. G.; Prévôt, A. S. H.; Baltensperger, U.; Dommen, J.

    2016-09-01

    Small volatile organic compounds (VOC) such as methane (CH4) have long been considered non-relevant to aerosol formation due to the high volatility of their oxidation products. However, even low aerosol yields from CH4, the most abundant VOC in the atmosphere, would contribute significantly to the total particulate carbon budget. In this study, organic aerosol (OA) mass yields from CH4 oxidation were evaluated at the Paul Scherrer Institute (PSI) smog chamber in the presence of inorganic and organic seed aerosols. Using labeled 13C methane, we could detect its oxidation products in the aerosol phase, with yields up to 0.09

  4. Pars planitis: Epidemiology, clinical characteristics, management and visual prognosis

    Directory of Open Access Journals (Sweden)

    Pinar Cakar Ozdal

    2015-01-01

    Full Text Available Pars planitis is an idiopathic chronic intermediate uveitis which predominantly affects children and adolescents, and accounts for 5-26.7% of pediatric uveitis. Although an autoimmune process with a genetic predisposition has been suggested, its etiology still remains unknown. The most common presenting symptoms are floaters and blurred vision. Diffuse vitreous cells, haze, snowballs and snowbanks are typical findings of pars planitis. Peripheral retinal vasculitis, optic disc edema and anterior segment inflammation are other well-known findings. Although pars planitis is known to be a benign form of uveitis in most cases, it may become a potentially blinding disease due to complications including cataract, cystoid macular edema, vitreous opacities and optic disc edema. Cystoid macular edema is the most common cause of visual morbidity. Band keratopathy, epiretinal membrane formation, vitreous condensation, neovascularizations, vitreous hemorrhage, retinal detachment, cyclitic membranes, glaucoma and amblyopia may develop as a consequence of the chronic course of the disease. Exclusion of infectious and non-infectious causes which may present with intermediate uveitis is of utmost importance before starting treatment. Treatment of pars planitis has been a controversial issue. There is no consensus specifically for treatment of cases with minimal inflammation and relatively good visual acuity. However, current experience shows that pars planitis may cause severe inflammation and needs an aggressive treatment. A stepladder approach including corticosteroids, immunosupressive agents, anti-tumor necrosis factor-alpha and pars plana vitrectomy and/or laser photocoagulation is the most commonly used method for treatment of pars planitis. Adequate control of inflammation and prompt detection of associated complications are crucial in order to improve the overall prognosis of the disease.

  5. Par Pond vegetation status Summer 1995 -- June survey descriptive summary

    International Nuclear Information System (INIS)

    The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the shoreline aquatic plant communities in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level, indicated that much of the original plant communities and the intermediate shoreline communities present on the exposed sediments have been lost. The extensive old-field and emergent marsh communities that were present on the exposed shoreline during the drawdown have been flooded and much of the pre-drawdown Par Pond aquatic plant communities have not had sufficient time for re-establishment. The shoreline does, however, have extensive beds of maidencane which extend from the shoreline margin to areas as deep as 2 and perhaps 3 meters. Scattered individual plants of lotus and watershield are common and may indicate likely directions of future wetland development in Par Pond. In addition, within isolated coves, which apparently received ground water seepage and/or stream surface flows during the period of the Par Pond draw down, extensive beds of waterlilies and spike rush are common. Invasion of willow and red maple occurred along the lake shoreline as well. Although not absent from this survey, evidence of the extensive redevelopment of the large cattail and eel grass beds was not observed in this first survey of Par Pond. Future surveys during the growing seasons of 1995, 1996, and 1997 along with the evaluation of satellite date to map the areal extent of the macrophyte beds of Par Pond are planned

  6. Par-4 Down-regulation Promotes Breast Cancer Recurrence by Preventing Multinucleation following Targeted Therapy

    OpenAIRE

    Alvarez, James V.; Pan, Tien-chi; Ruth, Jason; Feng, Yi; Zhou, Alice; Pant, Dhruv; Grimley, Joshua S.; Wandless, Thomas J.; DeMichele, Angela; Chodosh, Lewis A.

    2013-01-01

    Most deaths from breast cancer result from tumor recurrence, but the mechanisms underlying tumor relapse are largely unknown. We now report that Par-4 is down-regulated during tumor recurrence and that Par-4 down-regulation is necessary and sufficient to promote recurrence. Tumor cells with low Par-4 expression survive therapy by evading a program of Par-4-dependent multinucleation and apoptosis that is otherwise engaged following treatment. Low Par-4 expression is associated with poor respon...

  7. Charge distributions and coagulation of radioactive aerosols

    International Nuclear Information System (INIS)

    The self-charging of radioactive aerosols will be reduced by background ions, such as those produced by radioactive gases. The sources of these background ions and their production rates are specified for a reactor containment atmosphere during a possible nuclear accident. Previous theory is extended to calculate the charging of a polydisperse radioactive aerosol. Gaussian approximations to charge distributions on an aerosol of a given size, and are shown to give a good representation of the exact numerical charge distributions of a Cs aerosol at normal temperatures, and also for highly radioactive aerosol containing 131I in a containment atmosphere. Extensive calculations are performed for charged-induced modifications to Brownian coagulation rates between steady-state size distribution of these radioactive aerosols, and also between small-sized radioactive aerosol and larger (non-radioactive) aerosol. The results show considerable enhancements of the coagulation rates between large and small-sized aerosol, but also a strong suppression of coagulation between large particles. Rate modifications calculated using the Gaussian approximations are generally close to the exact values. Time-dependent calculations for a monodisperse α-decaying aerosol reveal enhancements in coagulation rates even when the average charge on the aerosol is positive. Our results are relevant to behaviour in a dusty plasma. (author)

  8. Une terreur par l’image

    Directory of Open Access Journals (Sweden)

    Annie DULONG

    2011-09-01

    Full Text Available Si d’autres événements — Hiroshima, la découverte des camps de concentration, la chute du mur de Berlin — ont, au cours du XXe siècle, marqué suffisamment l’imaginaire pour trouver leur réponse dans des œuvres d’art, le 11 septembre 2001 pose la question de la fictionnalisation autrement : il ne s’agit plus tant de combler les manques de la représentation, liés à l’absence d’images ou au délai dans leur dévoilement, mais bien de composer avec l’omniprésence d’une représentation martelée à la télévision et sur Internet. Que cette représentation soit partielle, tronquée et qu’il lui manque la présence des corps, ces grands absents des photographies et des images tournées par les journalistes, ne change rien au fait que c’est avec le trop-plein que les artistes doivent maintenant négocier.Cet article s’intéresse aux romans qui traitent l’événement de front au lieu de l’aborder sur un mode mineur, et a pour objectif de tracer un portrait de la représentation des médias dans les romans du 11 septembre 2001. Ces romans, outre le fait qu’ils traitent des événements de New York, ont comme point commun un personnage, ou décor : les médias, représentés par la télévision, l’Internet, les photographies de presse, interviennent dans les récits d’une manière significative et témoignent de la force brute des images. À travers une étude de certains des mécanismes à l’œuvre dans The Writing on the Wall (Lynne Sharon Schwartz, Extremely Loud and Incredibly Close (Jonathan Safran Foer, Falling Man (Don DeLillo et A Disorder Peculiar to the Country (Ken Kalfus, il s’agira de proposer des réponses à ces quelques questions : quel rôle les médias jouent-ils, et comment participent-ils au récit ? Quelle pression les images exercent-elles sur les personnages ? Que révèlent les personnages enfants dans leur rapport aux médias ? Quelle critique, finalement, les romans

  9. The effects of aerosols on climate

    International Nuclear Information System (INIS)

    Atmospheric aerosols (fine particles suspended in the atmosphere) can play two roles in the Earth’s radiation budget. In cloud-free air, aerosols scatter sunlight, some of which is reflected back to space (direct effect). Aerosols also determine the microphysical and optical properties of clouds (indirect effect). Whereas changes in natural aerosols are probably small during the last 100 years, there has been a large increase in the concentration of anthropogenic aerosols. The magnitude of their radiative effects is still very uncertain but seems to be sufficient to mask part of the global warming expected to stem from anthropogenic greenhouse gases. This paper presents the physical mechanisms of aerosol influence on climate. We then estimate the anthropogenic aerosol radiative effects and assess the climate response to these perturbations. (author)

  10. A statistical-numerical aerosol parameterization scheme

    Directory of Open Access Journals (Sweden)

    J.-P. Chen

    2013-05-01

    Full Text Available A new modal aerosol parameterization scheme, Statistical-Numerical Aerosol Parameterization (SNAP, was developed for studying aerosol processes and aerosol-cloud interactions in regional or global models. SNAP applies statistical fitting on numerical results to generate accurate parameterization formulas without sacrificing details of the growth kernel. Processes considered in SNAP include fundamental aerosol processes, as well as processes related to aerosol-cloud interactions. Comparison of SNAP with numerical solutions, analytical solutions, and binned aerosol model simulations showed that the new method performs well, with accuracy higher than that of the high-order numerical quadrature technique, at much less computation time. The SNAP scheme has been implemented in regional air quality models, producing results very close to those using binned-size schemes or numerical quadrature schemes.

  11. Review of models applicable to accident aerosols

    International Nuclear Information System (INIS)

    Estimations of potential airborne-particle releases are essential in safety assessments of nuclear-fuel facilities. This report is a review of aerosol behavior models that have potential applications for predicting aerosol characteristics in compartments containing accident-generated aerosol sources. Such characterization of the accident-generated aerosols is a necessary step toward estimating their eventual release in any accident scenario. Existing aerosol models can predict the size distribution, concentration, and composition of aerosols as they are acted on by ventilation, diffusion, gravity, coagulation, and other phenomena. Models developed in the fields of fluid mechanics, indoor air pollution, and nuclear-reactor accidents are reviewed with this nuclear fuel facility application in mind. The various capabilities of modeling aerosol behavior are tabulated and discussed, and recommendations are made for applying the models to problems of differing complexity

  12. Optical trapping of gold aerosols

    DEFF Research Database (Denmark)

    Schmitt, Regina K.; Pedersen, Liselotte Jauffred; Taheri, S. M.;

    2015-01-01

    Aerosol trapping has proven challenging and was only recently demonstrated.1 This was accomplished by utilizing an air chamber designed to have a minimum of turbulence and a laser beam with a minimum of aberration. Individual gold nano-particles with diameters between 80 nm and 200 nm were trappe...

  13. Saving Joint with Aerosol physics

    International Nuclear Information System (INIS)

    Full text: Using electro spray method to analyze wear debris from artificial joints. Well known aerosol techniques have been applied to determine the size distribution and concentration of wear particles found in joint fluids. The organic fraction (cells and large molecules) are removed by digestion. Knowing these data the risk of clogging of blood vessels can be medicinally reduced. (author)

  14. Immunization by a bacterial aerosol.

    Science.gov (United States)

    Garcia-Contreras, Lucila; Wong, Yun-Ling; Muttil, Pavan; Padilla, Danielle; Sadoff, Jerry; Derousse, Jessica; Germishuizen, Willem Andreas; Goonesekera, Sunali; Elbert, Katharina; Bloom, Barry R; Miller, Rich; Fourie, P Bernard; Hickey, Anthony; Edwards, David

    2008-03-25

    By manufacturing a single-particle system in two particulate forms (i.e., micrometer size and nanometer size), we have designed a bacterial vaccine form that exhibits improved efficacy of immunization. Microstructural properties are adapted to alter dispersive and aerosol properties independently. Dried "nanomicroparticle" vaccines possess two axes of nanoscale dimensions and a third axis of micrometer dimension; the last one permits effective micrometer-like physical dispersion, and the former provides alignment of the principal nanodimension particle axes with the direction of airflow. Particles formed with this combination of nano- and micrometer-scale dimensions possess a greater ability to aerosolize than particles of standard spherical isotropic shape and of similar geometric diameter. Here, we demonstrate effective application of this biomaterial by using the live attenuated tuberculosis vaccine bacille Calmette-Guérin (BCG). Prepared as a spray-dried nanomicroparticle aerosol, BCG vaccine exhibited high-efficiency delivery and peripheral lung targeting capacity from a low-cost and technically simple delivery system. Aerosol delivery of the BCG nanomicroparticle to normal guinea pigs subsequently challenged with virulent Mycobacterium tuberculosis significantly reduced bacterial burden and lung pathology both relative to untreated animals and to control animals immunized with the standard parenteral BCG. PMID:18344320

  15. Climatic impacts of anthropogenic aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Iversen, T. [Oslo Univ. (Norway)

    1996-03-01

    This paper was read at the workshop ``The Norwegian Climate and Ozone Research Programme`` held on 11-12 March 1996. Anthropogenic production of aerosols is mainly connected with combustion of fossil fuel. Measured by particulate mass, the anthropogenic sulphate production is the dominating source of aerosols in the Northern Hemisphere. Particles emitted in mechanical processes, fly ash etc. are less important because of their shorter atmospheric residence time. Possible climatological effects of anthropogenic aerosols are usually classified in two groups: direct and indirect. Direct effects are alterations of the radiative heating budget due to the aerosol particles in clear air. Indirect effects involve the interaction between particles and cloud processes. A simplified one-layer radiation model gave cooling in the most polluted mid-latitude areas and heating due to soot absorption in the Arctic. This differential trend in heating rates may have significant effects on atmospheric meridional circulations, which is important for the atmosphere as a thermodynamic system. Recently the description of sulphur chemistry in the hemispheric scale dispersion model has been improved and will be used in a model for Mie scattering and absorption

  16. Uncertainty quantification in aerosol dynamics

    International Nuclear Information System (INIS)

    The influence of uncertainty in coagulation and depositions mechanisms, as well as in the initial conditions, on the solution of the aerosol dynamic equation have been assessed using polynomial chaos theory. In this way, large uncertainties can be incorporated into the equations and their propagation as a function of space and time studied. We base our calculations on the simplified point model dynamic equation which includes coagulation and deposition removal mechanisms. Results are given for the stochastic mean aerosol density as a function of time as well as its variance. The stochastic mean and deterministic mean are shown to differ and the associated uncertainty, in the form of a sensitivity coefficient, is obtained as a function of time. In addition, we obtain the probability density function of the aerosol density and show how this varies with time. In view of the generally uncertain nature of an accidental aerosol release in a nuclear reactor accident, the polynomial chaos method is a particularly useful technique as it allows one to deal with a very large spread of input data and examine the effect this has on the quantities of interest. Convergence matters are studied and numerical values given.

  17. PIXE Analysis of Indoor Aerosols

    Science.gov (United States)

    Johnson, Christopher; Turley, Colin; Moore, Robert; Battaglia, Maria; Labrake, Scott; Vineyard, Michael

    2011-10-01

    We have performed a proton-induced X-ray emission (PIXE) analysis of aerosol samples collected in academic buildings at Union College to investigate the air quality in these buildings and the effectiveness of their air filtration systems. This is also the commissioning experiment for a new scattering chamber in the Union College Ion-Beam Analysis Laboratory. The aerosol samples were collected on Kapton foils using a nine-stage cascade impactor that separates particles according to their aerodynamic size. The foils were bombarded with beams of 2.2-MeV protons from the Union College 1.1-MV Pelletron Accelerator and the X-ray products were detected with an Amptek silicon drift detector. After subtracting the contribution from the Kapton foils, the X-ray energy spectra of the aerosol samples were analyzed using GUPIX software to determine the elemental concentrations of the samples. We will describe the collection of the aerosol samples, discuss the PIXE analysis, and present the results.

  18. Aerosol behaviour modeling and measurements

    International Nuclear Information System (INIS)

    Aerosol behavior within Liquid Metal Fast Breeder Reactor (LMFBR) containments is of critical importance since most of the radioactive species are expected to be associated with particulate forms and the mass of radiologically significant material leaked to the ambient atmosphere is directly related to the aerosol concentration airborne within the containment. Mathematical models describing the behavior of aerosols in closed environments, besides providing a direct means of assessing the importance of specific assumptions regarding accident sequences, will also serve as the basic tool with which to predict the consequences of various postulated accident situations. Consequently, considerable efforts have been recently directed toward the development of accurate and physically realistic theoretical aerosol behavior models. These models have accounted for various mechanisms affecting agglomeration rates of airborne particulate matter as well as particle removal rates from closed systems. In all cases, spatial variations within containments have been neglected and a well-mixed control volume has been assumed. Examples of existing computer codes formulated from the mathematical aerosol behavior models are the Brookhaven National Laboratory TRAP code, the PARDISEKO-II and PARDISEKO-III codes developed at Karlsruhe Nuclear Research Center, and the HAA-2, HAA-3, and HAA-3B codes developed by Atomics International. Because of their attractive short computation times, the HAA-3 and HAA-3B codes have been used extensively for safety analyses and are attractive candidates with which to demonstrate order of magnitude estimates of the effects of various physical assumptions. Therefore, the HAA-3B code was used as the nucleus upon which changes have been made to account for various physical mechanisms which are expected to be present in postulated accident situations and the latest of the resulting codes has been termed the HAARM-2 code. It is the primary purpose of the HAARM

  19. Combined pars plana vitrectomy-scleral buckle versus pars plana vitrectomy for proliferative vitreoretinopathy.

    Science.gov (United States)

    Lai, Frank H P; Lo, Ernie C F; Chan, Vesta C K; Brelen, Mårten; Lo, Wai Ling; Young, Alvin L

    2016-04-01

    The purpose of the study is to evaluate the surgical outcomes of combined pars plana vitrectomy-scleral buckle (PPV-SB) versus pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment complicated with proliferative vitreoretinopathy (PVR). One thousand one hundred and seventy four patients with rhegmatogenous retinal detachment surgery between January 2002 and December 2013 were retrospectively reviewed. Patients with grade C PVR treated with either combined PPV-SB or PPV alone were included in the study. Study outcomes included single surgery anatomic success rate and postoperative visual outcome at 12 months postoperatively. Seventy-seven patients with grade C PVR were identified for analysis. At the end of 12-month follow-up, 80.5 % eyes (33/41) in the PPV-SB group and 58.3 % eyes (21/36) in the PPV group achieved single surgery anatomical success. In a multiple logistic regression model, none of the baseline variables (age, gender, macula status, grade of PVR, extent of detachment, presence of vitreous hemorrhage, lens status, status of high myopia) nor types of retinal detachment surgery (use of scleral buckle, barrier endolaser, 360 degree endolaser, cryopexy, retinectomy, tamponade agent, phacoemulsification) had significant effect on single surgery anatomical success. The post-treatment mean logMAR visual acuity of the PPV-SB group was 1.58 ± 0.58 and the PPV group was 1.57 ± 0.61. There was no significant difference in the postoperative visual acuity between the two groups (P = 0.849). For patients with grade C PVR, PPV-SB did not demonstrate a superiority over PPV alone in achieving single surgery anatomical success. PMID:26260357

  20. Aerosol Absorption Measurements in MILAGRO.

    Science.gov (United States)

    Gaffney, J. S.; Marley, N. A.; Arnott, W. P.; Paredes-Miranda, L.; Barnard, J. C.

    2007-12-01

    During the month of March 2006, a number of instruments were used to determine the absorption characteristics of aerosols found in the Mexico City Megacity and nearby Valley of Mexico. These measurements were taken as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City (MAX-Mex) that was carried out in collaboration with the Megacity Interactions: Local and Global Research Observations (MILAGRO) campaign. MILAGRO was a joint effort between the DOE, NSF, NASA, and Mexican agencies aimed at understanding the impacts of a megacity on the urban and regional scale. A super-site was operated at the Instituto Mexicano de Petroleo in Mexico City (designated T-0) and at the Universidad Technologica de Tecamac (designated T-1) that was located about 35 km to the north east of the T-0 site in the State of Mexico. A third site was located at a private rancho in the State of Hidalgo approximately another 35 km to the northeast (designated T-2). Aerosol absorption measurements were taken in real time using a number of instruments at the T-0 and T-1 sites. These included a seven wavelength aethalometer, a multi-angle absorption photometer (MAAP), and a photo-acoustic spectrometer. Aerosol absorption was also derived from spectral radiometers including a multi-filter rotating band spectral radiometer (MFRSR). The results clearly indicate that there is significant aerosol absorption by the aerosols in the Mexico City megacity region. The absorption can lead to single scattering albedo reduction leading to values below 0.5 under some circumstances. The absorption is also found to deviate from that expected for a "well-behaved" soot anticipated from diesel engine emissions, i.e. from a simple 1/lambda wavelength dependence for absorption. Indeed, enhanced absorption is seen in the region of 300-450 nm in many cases, particularly in the afternoon periods indicating that secondary organic aerosols are contributing to the aerosol absorption. This is likely due

  1. Changes in airborne bacteria during a tropical burning season are correlated with satellite aerosol measurements

    Science.gov (United States)

    Mims, F., III

    Agricultural burning in the tropics generates vast quantities of smoke that can blanket entire countries and attenuate photosynthetically active radiation (PAR). Thick smoke also reduces the solar ultraviolet-B wavelengths that synthesize vitamin-D precur- sors in vertebrates and suppress many viruses and non-pigmented bacteria. As many pathogenic bacteria are non-pigmented, the latter finding may explain some of the in- creases in respiratory and other diseases that occur during episodes of severe aerosol loading. At Alta Floresta, Brazil, during the 1997 burning season, the correlation (r^2) of UV-B measured at the surface with the ratio of non-pigmented to total airborne bacteria colony forming units (CFUs) was 0.83. The correlation of the aerosol index measured from orbit by TOMS with the ratio of non-pigmented to total airborne bac- teria CFUs was 0.71. These findings suggest the application of satellite measurements of optical depth as a first approximation epidemiological tool for remote regions that have seasonally smokey skies. Further comparisons are warranted of surface measure- ments of airborne bacteria, UV-B and PAR with TOMS and MODIS observations of optical depth during severe air pollution events.

  2. Impact of the modal aerosol scheme GLOMAP-mode on aerosol forcing in the Hadley Centre Global Environmental Model

    OpenAIRE

    Bellouin, N; Mann, G.W.; Woodhouse, M.T.; Johnson, C.; Carslaw, K. S.; Dalvi, M.

    2012-01-01

    The Hadley Centre Global Environmental Model (HadGEM) includes two aerosol schemes: the Coupled Large-scale Aerosol Simulator for Studies in Climate (CLASSIC), and the new Global Model of Aerosol Processes (GLOMAP-mode). GLOMAP-mode is a modal aerosol microphysics scheme that simulates not only aerosol mass but also aerosol number, represents internally-mixed particles, and includes aerosol microphysical processes such as nucleation. In this study, both schemes provide hindcast simulations of...

  3. Composition and physical properties of the Asian Tropopause Aerosol Layer and the North American Tropospheric Aerosol Layer

    OpenAIRE

    Yu, P.; Toon, OB; Neely, RR; Martinsson, BG; Brenninkmeijer, CAM

    2015-01-01

    Recent studies revealed layers of enhanced aerosol scattering in the upper troposphere and lower stratosphere over Asia (Asian Tropopause Aerosol Layer (ATAL)) and North America (North American Tropospheric Aerosol Layer (NATAL)). We use a sectional aerosol model (Community Aerosol and Radiation Model for Atmospheres (CARMA)) coupled with the Community Earth System Model version 1 (CESM1) to explore the composition and optical properties of these aerosol layers. The observed aerosol extinctio...

  4. Par Pond vegetation status Summer 1995 -- October survey descriptive summary

    International Nuclear Information System (INIS)

    The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the emergent shoreline aquatic plant communities began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level and continued with this late October survey. Communities similar to the pre-drawdown Par Pond aquatic plant communities are becoming re-established; especially, beds of maiden cane, lotus, waterlily, and watershield are now extensive and well established. Cattail occurrence continues to increase, but large beds common to Par Pond prior to the drawdown have not formed. Future surveys throughout 1996 and 1997, along with the continued evaluation of satellite data to map the areal extent of the macrophyte beds of Par Pond, are planned

  5. Par Pond vegetation status Summer 1995 -- September survey descriptive summary

    International Nuclear Information System (INIS)

    The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the emergent shoreline aquatic plant communities began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level and continued with this mid-September survey. Communities similar to the pre-drawdown Par Pond aquatic plant communities are becoming re-established; especially, beds of maidencane, lotus, waterlily, and watershield are now extensive and well established. Cattail occurrence continues to increase, but large beds common to Par Pond prior to the drawdown have not formed. Future surveys during the late growing seasons of 1995, and throughout 1996 and 1997, along with the evaluation of satellite data to map the areal extent of the macrophyte beds of Par Pond, are planned

  6. Aerosol classification by airborne high spectral resolution lidar observations

    Directory of Open Access Journals (Sweden)

    S. Groß

    2012-10-01

    Full Text Available During four aircraft field experiments with the DLR research aircraft Falcon in 1998 (LACE, 2006 (SAMUM-1 and 2008 (SAMUM-2 and EUCAARI, airborne High Spectral Resolution Lidar (HSRL and in situ measurements of aerosol microphysical and optical properties were performed. Altogether, the properties of six different aerosol types and aerosol mixtures – Saharan mineral dust, Saharan dust mixtures, Canadian biomass burning aerosol, African biomass burning aerosol, anthropogenic pollution aerosol, and marine aerosol have been studied. On the basis of this extensive HSRL data set, we present an aerosol classification scheme which is also capable to identify mixtures of different aerosol types. We calculated mixing lines that allowed us to determine the contributing aerosol types. The aerosol classification scheme was validated with in-situ measurements and backward trajectory analyses. Our results demonstrate that the developed aerosol mask is capable to identify complex stratifications with different aerosol types throughout the atmosphere.

  7. Toxicity of atmospheric aerosols on marine phytoplankton

    Science.gov (United States)

    Paytan, A.; Mackey, K.R.M.; Chen, Y.; Lima, I.D.; Doney, S.C.; Mahowald, N.; Labiosa, R.; Post, A.F.

    2009-01-01

    Atmospheric aerosol deposition is an important source of nutrients and trace metals to the open ocean that can enhance ocean productivity and carbon sequestration and thus influence atmospheric carbon dioxide concentrations and climate. Using aerosol samples from different back trajectories in incubation experiments with natural communities, we demonstrate that the response of phytoplankton growth to aerosol additions depends on specific components in aerosols and differs across phytoplankton species. Aerosol additions enhanced growth by releasing nitrogen and phosphorus, but not all aerosols stimulated growth. Toxic effects were observed with some aerosols, where the toxicity affected picoeukaryotes and Synechococcus but not Prochlorococcus.We suggest that the toxicity could be due to high copper concentrations in these aerosols and support this by laboratory copper toxicity tests preformed with Synechococcus cultures. However, it is possible that other elements present in the aerosols or unknown synergistic effects between these elements could have also contributed to the toxic effect. Anthropogenic emissions are increasing atmospheric copper deposition sharply, and based on coupled atmosphere-ocean calculations, we show that this deposition can potentially alter patterns of marine primary production and community structure in high aerosol, low chlorophyll areas, particularly in the Bay of Bengal and downwind of South and East Asia.

  8. OXYDATION DU CYCLOHEXANE PAR COMPLEXE DE RUTHÉNIUM

    OpenAIRE

    HAMOUDI, Badreddine

    2008-01-01

    Le complexe RuCl2(PPh3)3 a été préparé dans le but de son application sur la réaction d’oxydation du cyclohexane en cyclhexanol et cyclohexanone. Les analyses par chromatographie en phase gaz sur la phase organique montrent la production de l’alcool et la cétone dans le cas du t-BuOOH comme oxydant, ce qui n’est le cas avec l’eau oxygénée et l’oxygène moléculaire. La réaction a été effectuée dans différents solvants, où l’eau a apportée une meilleure conversion par rapport a...

  9. CFD Application to Hydrogen Risk Analysis and PAR Qualification

    Directory of Open Access Journals (Sweden)

    Jinbiao Xiong

    2009-01-01

    Full Text Available A three dimensional computation fluid dynamics (CFD code, GASFLOW, is applied to analyze the hydrogen risk for Qinshan-II nuclear power plant (NPP. In this paper, the effect of spray modes on hydrogen risk in the containment during a large break loss of coolant accident (LBLOCA is analyzed by selecting three different spray strategies, that is, without spray, with direct spray and with both direct and recirculation spray. A strong effect of spray modes on hydrogen distribution is observed. However, the efficiency of the passive auto-catalytic recombiners (PAR is not substantially affected by spray modes. The hydrogen risk is significantly increased by the direct spray, while the recirculation spray has minor effect on it. In order to simulate more precisely the processes involved in the PAR operation, a new PAR model is developed using CFD approach. The validation shows that the results obtained by the model agree well with the experimental results.

  10. Terapia Miofuncional en pacientes con parálisis cerebral

    OpenAIRE

    Gónzalez Amigo, José

    2015-01-01

    En el presente trabajo, se va a llevar a cabo una visión de la parálisis cerebral desde el punto de vista de la motricidad. La parálisis cerebral es una patología que se caracteriza fundamentalmente por una alteración a nivel motriz, que puede afectar a las diferentes extremidades así como a los órganos involucrados en el habla. Estas limitaciones en la región orofacial pueden producir importantes distorsiones y como consecuencia el discurso puede resultar ininteligible para los interlocutore...

  11. La parálisis cerebral en el cine

    OpenAIRE

    Merino Marcos, María Lucila

    2005-01-01

    [ES] En los últimos veinticinco años se han rodado un número importante de películas en las que el protagonista o algún personaje secundario presentaban o simulaban una parálisis cerebral. Estos personajes en ocasiones han sido interpretados por personas con minusvalías. En la narración de su historia las cintas han incluido diversos aspectos sanitario-asistenciales, sociales y familiares obligados en el campo de la parálisis cerebral. [EN] In the last twenty-five years, a number of import...

  12. Apprentissage par Renforcement Développemental en Robotique Autonome

    OpenAIRE

    Sarzyniec, Luc; Buffet, Olivier; Dutech, Alain

    2011-01-01

    National audience Cet article présente une approche développementale de l'apprentissage par renforcement dans un cadre de robotique autonome. Le but est de permettre au robot de tirer parti de la richesse de son environnement sans que cette richesse ne le noie sous trop d'information à traiter. L'idée principale testée ici est de faire croître les capacités perceptives et motrices de l'agent au fur et à mesure de l'apprentissage. Cette approche est combinée avec un apprentissage par renfor...

  13. Ejercicios activos en la parálisis facial

    OpenAIRE

    Bohoyo Aramburu, Cristina

    2013-01-01

    Diseño: Se trata de una revisión bibliográfica en la que se incluyen revisiones sistemáticas y artículos sobre el tratamiento de la parálisis facial mediante ejercicios faciales, que en su conjunto engloban lo que se denomina la “mímicoterapia”. Objetivos: el objetivo principal es determinar la eficacia de los ejercicios faciales activos en el tratamiento de la parálisis de Bell. El objetivo secundario es describir dichos ejercicios. Métodos: se ha realizado una búsqueda mediante la base d...

  14. Cyclanthaceae no estado do Pará, Brasil Cyclanthaceae in Pará State, Brazil

    Directory of Open Access Journals (Sweden)

    Eduardo da Silva Leal

    2012-12-01

    Full Text Available Cyclanthaceae apresenta distribuição exclusiva na região neotropical sendo bem diversificada nas terras baixas das florestas pluviais tropicais, ocorrendo do sul do México até a Mata Atlântica do sul do Brasil. Consistem de ervas terrestres, epífitas, hemiepífitas ou lianas. O tratamento taxonômico de Cyclanthaceae no Pará foi baseado em coleções de herbário, trabalhos de campo e consulta a bibliografia referente à família. Foram registradas 11 espécies: Asplundia altiscandens E.S. Leal, A. fanshawei (Maguire Harling, A. glandulosa (Gleason Harling, A. heteranthera Harling, A. latifrons (Drude Harling, A. schizotepala Harling, A. xiphophylla Harling, Cyclanthus bipartitus Poit. ex A. Rich., Evodianthus funifer (Poit. Lindm., Ludovia lancifolia Brongn. e Thoracocarpus bissectus (Vell. Harling. São apresentadas chave de identificação, descrições e ilustrações das espécies, além de comentários sobre distribuição geográfica, hábitat e período de floração e frutificação.Cyclanthaceae is a family with a distribution exclusively in the Neotropics and is well diversified in lowland rainforests, occurring from southern Mexico to the Atlantic Forest of southern Brazil. The family consists of terrestrial herbs, epiphytes, hemiepiphytes and lianas. This taxonomic treatment of the Cyclanthaceae from the state of Pará was based on herbarium specimens, fieldwork, and the literature. Eleven species were recorded: Asplundia altiscandens E.S. Leal, A. fanshawei (Maguire Harling, A. glandulosa (Gleason Harling, A. heteranthera Harling, A. latifrons (Drude Harling, A. schizotepala Harling, A. xiphophylla Harling, Cyclanthus bipartitus Poit. ex A. Rich., Evodianthus funifer (Poit. Lindm., Ludovia lancifolia Brongn. and Thoracocarpus bissectus (Vell. Harling. An identification key, descriptions and illustrations of species are presented. Additional information on the geographic distribution, habitat, and flowering and

  15. CCN activity of aliphatic amine secondary aerosol

    Directory of Open Access Journals (Sweden)

    X. Tang

    2014-01-01

    Full Text Available Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g. hydroxyl radical and nitrate radical. The particle composition can contain both secondary organic aerosol (SOA and inorganic salts. The fraction of organic to inorganic materials in the particulate phase influences aerosol hygroscopicity and cloud condensation nuclei (CCN activity. SOA formed from trimethylamine (TMA and butylamine (BA reactions with hydroxyl radical (OH is composed of organic material of low hygroscopicity (single hygroscopicity parameter, κ ≤ 0.25. Secondary aerosol formed from the tertiary aliphatic amine (TMA with N2O5 (source of nitrate radical, NO3, contains less volatile compounds than the primary aliphatic amine (BA aerosol. TMA + N2O5 form semi-volatile organics in low RH conditions that have κ ~ 0.20, indicative of slightly soluble organic material. As RH increases, several inorganic amine salts are formed as a result of acid-base reactions. The CCN activity of the humid TMA-N2O5 aerosol obeys Zdanovskii, Stokes, and Robinson (ZSR ideal mixing rules. Higher CCN activity (κ > 0.3 was also observed for humid BA+N2O5 aerosols compared with dry aerosol (κ ~ 0.2, as a result of the formation of inorganic salts such as NH4NO3 and butylamine nitrate (C4H11N · HNO3. Compared with TMA, BA+N2O5 reactions produce more volatile aerosols. The BA+N2O5 aerosol products under humid experiments were found to be very sensitive to the temperature within the stream-wise continuous flow thermal gradient CCN counter. The CCN counter, when set above a 21 °C temperature difference, evaporates BA+N2O5 aerosol formed at RH ≥ 30%; κ ranges from 0.4 to 0.7 and is dependent on the instrument supersaturation (ss settings. The aerosol behaves non-ideally, hence simple ZSR rules cannot be applied to the CCN results from the primary aliphatic amine system. Overall, aliphatic amine aerosol systems κ ranges from 0.2 < κ < 0.7. This work indicates that

  16. How We Can Constrain Aerosol Type Globally

    Science.gov (United States)

    Kahn, Ralph

    2016-01-01

    In addition to aerosol number concentration, aerosol size and composition are essential attributes needed to adequately represent aerosol-cloud interactions (ACI) in models. As the nature of ACI varies enormously with environmental conditions, global-scale constraints on particle properties are indicated. And although advanced satellite remote-sensing instruments can provide categorical aerosol-type classification globally, detailed particle microphysical properties are unobtainable from space with currently available or planned technologies. For the foreseeable future, only in situ measurements can constrain particle properties at the level-of-detail required for ACI, as well as to reduce uncertainties in regional-to-global-scale direct aerosol radiative forcing (DARF). The limitation of in situ measurements for this application is sampling. However, there is a simplifying factor: for a given aerosol source, in a given season, particle microphysical properties tend to be repeatable, even if the amount varies from day-to-day and year-to-year, because the physical nature of the particles is determined primarily by the regional environment. So, if the PDFs of particle properties from major aerosol sources can be adequately characterized, they can be used to add the missing microphysical detail the better sampled satellite aerosol-type maps. This calls for Systematic Aircraft Measurements to Characterize Aerosol Air Masses (SAM-CAAM). We are defining a relatively modest and readily deployable, operational aircraft payload capable of measuring key aerosol absorption, scattering, and chemical properties in situ, and a program for characterizing statistically these properties for the major aerosol air mass types, at a level-of-detail unobtainable from space. It is aimed at: (1) enhancing satellite aerosol-type retrieval products with better aerosol climatology assumptions, and (2) improving the translation between satellite-retrieved aerosol optical properties and

  17. Beschrijving van een verdampings-condensatie aerosol generator voor de produktie van submicron aerosol

    NARCIS (Netherlands)

    Feijt; A.*; Meulen; A.van der

    1985-01-01

    Dit rapport is een handleiding voor een bedrijfszeker, routinematig gebruik van een zgn. Evaporation-Condensation aerosol Conditioner. Met deze aerosol generatie apparatuur kunnen op stabiele, reproduceerbare manier zeer hoge concentraties (tot 1 miljoen deeltjes per cc) monodispers submicron ae

  18. Periodicities in Aerosol Optical Depths

    CERN Document Server

    Ramachandran, S; Verma, Amit; Panigrahi, Prasanta K

    2011-01-01

    We investigate the temporal and spatial variability in aerosol optical depth (AOD) over different geographic locations in India due to their important role in the earth-atmosphere radiation budget. The use of continuous wavelet transform pinpoints the spatio-temporal non-stationarity of the periodic variations in the AOD depending on local factors. The optimal time-frequency localization ability of Morlet wavelet accurately isolates the periodic features in the different frequency domains, to study the variations in the dominant periods due to local effects. The origin of the effects on the periodic modulations is then related to physical phenomena of regional nature, which throws considerable light on the observed variations in aerosol optical depths. We also find the phase relationship between different locations and to identify the possible correlations between different geographic locations and related environmental variations.

  19. Photostimulated Aggregation of Metal Aerosols

    CERN Document Server

    Karpov, Sergei V

    2010-01-01

    The effect of optical radiation on the rate of aggregation of nanoscopic particles is studied in metal aerosols. It has been shown that under light exposure, polydisperse metal aerosols can aggregate up to two orders faster due to the size dependent photoelectron effect from nanoparticles. Different size nanoparticles undergo mutual heteropolar charging when exchanging photoelectrons through the interparticle medium to result in an increased rate of aggregation. It is shown that long-range electrostatic attractive forces drive the particles into closer distances where the short-range Van-der-Waals forces become dominating. Attention is drawn to the fact that this effect may occur in various types of dispersed systems as well as in natural heteroaerosols.

  20. A mathematical model of aerosol holding chambers

    DEFF Research Database (Denmark)

    Zak, M; Madsen, J; Berg, E;

    1999-01-01

    A mathematical model of aerosol delivery from holding chambers (spacers) was developed incorporating tidal volume (VT), chamber volume (Vch), apparatus dead space (VD), effect of valve insufficiency and other leaks, loss of aerosol by immediate impact on the chamber wall, and fallout of aerosol...... in the chamber with time. Four different spacers were connected via filters to a mechanical lung model, and aerosol delivery during "breathing" was determined from drug recovery from the filters. The formula correctly predicted the delivery of budesonide aerosol from the AeroChamber (Trudell Medical, London......-mentioned factors, initial loss of aerosol by impact on the chamber wall is most important for the efficiency of a spacer. With a VT of 195 mL, the AeroChamber and Babyhaler were emptied in two breaths, the NebuChamber in four breaths, and the Nebuhaler in six breaths. Insufficiencies of the expiratory valves were...

  1. Immunization by a bacterial aerosol

    OpenAIRE

    Garcia-Contreras, Lucila; Wong, Yun-Ling; Muttil, Pavan; Padilla, Danielle; Sadoff, Jerry; DeRousse, Jessica; Germishuizen, Willem Andreas; Goonesekera, Sunali; Elbert, Katharina; Bloom, Barry R.; Miller, Rich; Fourie, P. Bernard; Hickey, Anthony; Edwards, David

    2008-01-01

    By manufacturing a single-particle system in two particulate forms (i.e., micrometer size and nanometer size), we have designed a bacterial vaccine form that exhibits improved efficacy of immunization. Microstructural properties are adapted to alter dispersive and aerosol properties independently. Dried “nanomicroparticle” vaccines possess two axes of nanoscale dimensions and a third axis of micrometer dimension; the last one permits effective micrometer-like physical dispersion, and the form...

  2. Aerosol-cloud interaction inferred from MODIS satellite data and global aerosol models

    OpenAIRE

    G. Myhre; F. Stordal; M. Johnsrud; Y. J. Kaufman; D. Rosenfeld; Storelvmo, T.; Kristjansson, J. E.; Berntsen, T. K.; Myhre, A.; I. S. A. Isaksen

    2007-01-01

    We have used the MODIS satellite data and two global aerosol models to investigate the relationships between aerosol optical depth (AOD) and cloud parameters that may be affected by the aerosol concentration. The relationships that are studied are mainly between AOD, on the one hand, and cloud cover, cloud liquid water path, and water vapour, on the other. Additionally, cloud droplet effective radius, cloud optical depth, cloud top pressure and aerosol Ångström exponent, have been a...

  3. High resolution aerosol optical thickness retrieval over the Pearl River Delta region with improved aerosol modelling

    Institute of Scientific and Technical Information of China (English)

    WONG ManSing; NICHOL Janet; LEE Kwon Ho; LI ZhanQing

    2009-01-01

    Aerosol retrieval algorithms for the MODerate Resolution Imaging Spectroradiometer (MODIS) have been developed to estimate aerosol and microphysical properties of the atmosphere, which help to address aerosol climatic issues at global scale. However, higher spatial resolution aerosol products for urban areas have not been well researched mainly due to the difficulty of differentiating aerosols from bright surfaces in urban areas. Here, a new aerosol retrieval algorithm using the MODIS 500 m resolu-tion images is described, to retrieve aerosol properties over Hong Kong and the Pearl River Delta re-gion. The rationale of our technique is to first estimate the aerosol reflectance by decomposing the top-of-atmosphere reflectance from surface reflectance and Rayleigh path reflectance. For the deter-mination of surface reflectance, a modified Minimum Reflectance Technique (MRT) is used, and MRT images are computed for different seasons. A strong correlation is shown between the surface reflec-tance of MRT images and MODIS land surface reflectance products (MOD09), with a value of 0.9. For conversion of aerosol reflectance to Aerosol Optical Thickness (AOT), comprehensive Look Up Tables (LUT) are constructed, in which aerosol properties and sun-viewing geometry in the radiative transfer calculations are taken into account. Four aerosol types, namely mixed urban, polluted urban, dust, and heavy pollution, were derived using cluster analysis on three years of AERONET measurements in Hong Kong. Their aerosol properties were input for LUT calculation. The resulting 500 m AOT images are highly correlated (r=0.89) with AERONET sunphotometer observations in Hong Kong. This study demonstrates the applicability of aerosol retrieval at fine resolution scale in urban areas, which can assist the study of aerosol loading distribution and the impact of localized and transient pollution on urban air quality. In addition, the MODIS 500 m AOT images can be used to study cross

  4. High resolution aerosol optical thickness retrieval over the Pearl River Delta region with improved aerosol modelling

    Institute of Scientific and Technical Information of China (English)

    WONG; ManSing; NICHOL; Janet; LEE; Kwon; Ho

    2009-01-01

    Aerosol retrieval algorithms for the MODerate Resolution Imaging Spectroradiometer (MODIS) have been developed to estimate aerosol and microphysical properties of the atmosphere, which help to address aerosol climatic issues at global scale. However, higher spatial resolution aerosol products for urban areas have not been well researched mainly due to the difficulty of differentiating aerosols from bright surfaces in urban areas. Here, a new aerosol retrieval algorithm using the MODIS 500 m resolution images is described, to retrieve aerosol properties over Hong Kong and the Pearl River Delta region. The rationale of our technique is to first estimate the aerosol reflectance by decomposing the top-of-atmosphere reflectance from surface reflectance and Rayleigh path reflectance. For the determination of surface reflectance, a modified Minimum Reflectance Technique (MRT) is used, and MRT images are computed for different seasons. A strong correlation is shown between the surface reflectance of MRT images and MODIS land surface reflectance products (MOD09), with a value of 0.9. For conversion of aerosol reflectance to Aerosol Optical Thickness (AOT), comprehensive Look Up Tables (LUT) are constructed, in which aerosol properties and sun-viewing geometry in the radiative transfer calculations are taken into account. Four aerosol types, namely mixed urban, polluted urban, dust, and heavy pollution, were derived using cluster analysis on three years of AERONET measurements in Hong Kong. Their aerosol properties were input for LUT calculation. The resulting 500 m AOT images are highly correlated (r = 0.89) with AERONET sunphotometer observations in Hong Kong. This study demonstrates the applicability of aerosol retrieval at fine resolution scale in urban areas, which can assist the study of aerosol loading distribution and the impact of localized and transient pollution on urban air quality. In addition, the MODIS 500 m AOT images can be used to study cross

  5. Beschrijving van een verdampings-condensatie aerosol generator voor de produktie van submicron aerosol

    OpenAIRE

    Feijt; Meulen, van der, A.; De, A.

    1985-01-01

    Dit rapport is een handleiding voor een bedrijfszeker, routinematig gebruik van een zgn. Evaporation-Condensation aerosol Conditioner. Met deze aerosol generatie apparatuur kunnen op stabiele, reproduceerbare manier zeer hoge concentraties (tot 1 miljoen deeltjes per cc) monodispers submicron aerosol geproduceerd worden. De aerosol afmetingen kunnen gevarieerd worden tussen 0.3 en 1.2 mu-m in diameter de geometrische standaardafwijking bedraagt circa 1.25-1.4.

  6. Ice-condenser aerosol tests

    International Nuclear Information System (INIS)

    This report presents the results of an experimental investigation of aerosol particle transport and capture using a full-scale height and reduced-scale cross section test facility based on the design of the ice compartment of a pressurized water reactor (PWR) ice-condenser containment system. Results of 38 tests included thermal-hydraulic as well as aerosol particle data. Particle retention in the test section was greatly influenced by thermal-hydraulic and aerosol test parameters. Test-average decontamination factor (DF) ranged between 1.0 and 36 (retentions between ∼0 and 97.2%). The measured test-average particle retentions for tests without and with ice and steam ranged between DF = 1.0 and 2.2 and DF = 2.4 and 36, respectively. In order to apparent importance, parameters that caused particle retention in the test section in the presence of ice were steam mole fraction (SMF), noncondensible gas flow rate (residence time), particle solubility, and inlet particle size. Ice-basket section noncondensible flows greater than 0.1 m3/s resulted in stable thermal stratification whereas flows less than 0.1 m3/s resulted in thermal behavior termed meandering with frequent temperature crossovers between flow channels. 10 refs., 66 figs., 16 tabs

  7. Characterization of Aerosols Containing Microcystin

    Directory of Open Access Journals (Sweden)

    Lorraine C. Backer

    2007-10-01

    Full Text Available Toxic blooms of cyanobacteria are ubiquitous in both freshwater and brackishwater sources throughout the world. One class of cyanobacterial toxins, calledmicrocystins, is cyclic peptides. In addition to ingestion and dermal, inhalation is a likelyroute of human exposure. A significant increase in reporting of minor symptoms,particularly respiratory symptoms was associated with exposure to higher levels ofcyanobacteria during recreational activities. Algae cells, bacteria, and waterborne toxinscan be aerosolized by a bubble-bursting process with a wind-driven white-capped wavemechanism. The purposes of this study were to: evaluate sampling and analysis techniquesfor microcystin aerosol, produce aerosol droplets containing microcystin in the laboratory,and deploy the sampling instruments in field studies. A high-volume impactor and an IOMfilter sampler were tried first in the laboratory to collect droplets containing microcystins.Samples were extracted and analyzed for microcystin using an ELISA method. Thelaboratory study showed that cyanotoxins in water could be transferred to air via a bubble-bursting process. The droplets containing microcystins showed a bimodal size distributionwith the mass median aerodynamic diameter (MMAD of 1.4 and 27.8 μm. The samplingand analysis methods were successfully used in a pilot field study to measure microcystinaerosol in situ.

  8. Chromism of Model Organic Aerosol

    Science.gov (United States)

    Rincon, Angela; Guzman, Marcelo; Hoffmann, Michael; Colussi, Agustin

    2008-03-01

    The optical properties of the atmospheric aerosol play a fundamental role in the Earth's radiative balance. Since more than half of the aerosol mass consists of complex organic matter that absorbs in the ultraviolet and visible regions of the spectrum, it is important to establish the identity of the organic chromophores. Here we report studies on the chromism vs. chemical composition of photolyzed (lambda longer than 305 nm) solutions of pyruvic acid, a widespread aerosol component, under a variety of experimental conditions that include substrate concentration, temperature and the presence of relevant spectator solutes, such ammonium sulfate. We use high resolution mass- and 13C NMR-spectrometries to track chemical speciation in photolyzed solutions as they undergo thermochromic and photobleaching cycles. Since the chemical identity of the components of these mixtures does not change in these cycles, in which photobleached solutions gradually recover their yellow color in the dark with non-conventional kinetics typical of aggregation processes, we infer that visible absorptions likely involve the intermolecular coupling of carbonyl chromophores in supramolecular assemblies made possible by the polyfunctional nature of the products of pyruvic acid photolysis.

  9. Ice-condenser aerosol tests

    Energy Technology Data Exchange (ETDEWEB)

    Ligotke, M.W.; Eschbach, E.J.; Winegardner, W.K. (Pacific Northwest Lab., Richland, WA (United States))

    1991-09-01

    This report presents the results of an experimental investigation of aerosol particle transport and capture using a full-scale height and reduced-scale cross section test facility based on the design of the ice compartment of a pressurized water reactor (PWR) ice-condenser containment system. Results of 38 tests included thermal-hydraulic as well as aerosol particle data. Particle retention in the test section was greatly influenced by thermal-hydraulic and aerosol test parameters. Test-average decontamination factor (DF) ranged between 1.0 and 36 (retentions between {approximately}0 and 97.2%). The measured test-average particle retentions for tests without and with ice and steam ranged between DF = 1.0 and 2.2 and DF = 2.4 and 36, respectively. In order to apparent importance, parameters that caused particle retention in the test section in the presence of ice were steam mole fraction (SMF), noncondensible gas flow rate (residence time), particle solubility, and inlet particle size. Ice-basket section noncondensible flows greater than 0.1 m{sup 3}/s resulted in stable thermal stratification whereas flows less than 0.1 m{sup 3}/s resulted in thermal behavior termed meandering with frequent temperature crossovers between flow channels. 10 refs., 66 figs., 16 tabs.

  10. Initial steps of aerosol growth

    Directory of Open Access Journals (Sweden)

    O. Kulmala

    2004-09-01

    Full Text Available The formation and growth of atmospheric aerosols depend on several steps, namely nucleation, initial steps of growth and subsequent – mainly condensational – growth. This work focuses on the initial steps of growth, meaning the growth right after nucleation, where the interplay of curvature effects and thermodynamics has a significant role on the growth kinetics. More specifically, we investigate how ion clusters and aerosol particles grow from 1.5 nm to 20 nm in atmospheric conditions using experimental data obtained by air ion and aerosol spectrometers. The measurements have been performed at a boreal forest site in Finland. The observed trend that the growth rate seems to increase as a function of size can be used to investigate possible growth mechanisms. Such a growth rate is consistent with a recently suggested nano-Köhler mechanism, in which growth is activated at a certain size with respect to condensation of organic vapors. The results also imply that charge-enhance growth associated with ion-mediated nucleation plays only a minor role in the initial steps of growth, since it would imply a clear decrease of the growth rate with size. Finally, further evidence was obtained on the earlier suggestion that atmospheric nucleation and the subsequent growth of fresh nuclei are likely to be uncoupled phenomena via different participating vapors.

  11. Initial steps of aerosol growth

    Directory of Open Access Journals (Sweden)

    M. Kulmala

    2004-01-01

    Full Text Available The formation and growth of atmospheric aerosols depend on several steps, namely nucleation, initial steps of growth and subsequent – mainly condensational – growth. This work focuses on the initial steps of growth, meaning the growth right after nucleation, where the interplay of curvature effects and thermodynamics has a significant role on the growth kinetics. More specifically, we investigate how ion clusters and aerosol particles grow from 1.5 nm to 20 nm (diameter in atmospheric conditions using experimental data obtained by air ion and aerosol spectrometers. The measurements have been performed at a boreal forest site in Finland. The observed trend that the growth rate seems to increase as a function of size can be used to investigate possible growth mechanisms. Such a growth rate is consistent with a recently suggested nano-Köhler mechanism, in which growth is activated at a certain size with respect to condensation of organic vapors. The results also imply that charge-enhanced growth associated with ion-mediated nucleation plays only a minor role in the initial steps of growth, since it would imply a clear decrease of the growth rate with size. Finally, further evidence was obtained on the earlier suggestion that atmospheric nucleation and the subsequent growth of fresh nuclei are likely to be uncoupled phenomena via different participating vapors.

  12. Initial steps of aerosol growth

    Science.gov (United States)

    Kulmala, M.; Laakso, L.; Lehtinen, K. E. J.; Riipinen, I.; Dal Maso, M.; Anttila, T.; Kerminen, V.-M.; Hõrrak, U.; Vana, M.; Tammet, H.

    2004-12-01

    The formation and growth of atmospheric aerosols depend on several steps, namely nucleation, initial steps of growth and subsequent - mainly condensational - growth. This work focuses on the initial steps of growth, meaning the growth right after nucleation, where the interplay of curvature effects and thermodynamics has a significant role on the growth kinetics. More specifically, we investigate how ion clusters and aerosol particles grow from 1.5 nm to 20 nm (diameter) in atmospheric conditions using experimental data obtained by air ion and aerosol spectrometers. The measurements have been performed at a boreal forest site in Finland. The observed trend that the growth rate seems to increase as a function of size can be used to investigate possible growth mechanisms. Such a growth rate is consistent with a recently suggested nano-Köhler mechanism, in which growth is activated at a certain size with respect to condensation of organic vapors. The results also imply that charge-enhanced growth associated with ion-mediated nucleation plays only a minor role in the initial steps of growth, since it would imply a clear decrease of the growth rate with size. Finally, further evidence was obtained on the earlier suggestion that atmospheric nucleation and the subsequent growth of fresh nuclei are likely to be uncoupled phenomena via different participating vapors.

  13. Characterization of Sodium Spray Aerosols

    International Nuclear Information System (INIS)

    The consequences of pool and spray fires require evaluation in the safety analysis of liquid metal-cooled fast breeder reactors. Sodium spray fires are characterized by high temperature and pressure, produced during the rapid combustion of sodium in air. Following the initial energy release, some fraction of the reaction products are available as aerosols which follow the normal laws of agglomeration, growth, settling, and plating. An experimental study is underway at Atomics International to study the characteristics of high concentration sprays of liquid sodium in reduced oxygen atmospheres and in air. The experiments are conducted in a 31.5 ft3 (2 ft diam. by 10 ft high) vessel, certified for a pressure of 100 lb/in2 (gauge). The spray injection apparatus consists of a heated sodium supply pot and a spray nozzle through which liquid sodium is driven by nitrogen pressure. Spray rate and droplet size can be varied by the injection velocity (nozzle size, nitrogen pressure, and sodium temperature). Aerosols produced in 0, 4, and 10 vol. % oxygen environments have been studied. The concentration and particle size distribution of the material remaining in the air after the spray injection and reaction period are measured. Fallout rates are found to be proportional to the concentration of aerosol which remains airborne following the spray period. (author)

  14. Survival of virulent Legionella pneumophila in aerosols.

    OpenAIRE

    Hambleton, P.; Broster, M G; Dennis, P J; Henstridge, R.; Fitzgeorge, R.; Conlan, J W

    1983-01-01

    Aqueous suspensions of virulent Legionella pneumophila grown on solid medium retained virulence and aerosol survival characteristics for several months. Significant numbers of viable organisms were recovered from aerosols held at various relative humidities (r.h.) for up to 2 h. The organisms survived best at 65% r.h. and were least stable at 55% r.h. Exponential phase broth-grown organisms survived poorly in aerosols in comparison with stationary phase broth cultures or organisms grown on so...

  15. Atmospheric Aerosols at the MAGIC Site

    CERN Document Server

    Garrido, Daniel; Doro, Michele; Font, Lluís; López-Oramas, Alicia; Moralejo, Abelardo

    2013-01-01

    We investigate the performance of the MAGIC telescopes under three simulated atmospheric conditions: an increased aerosol content in the lower part of the troposphere, the presence of thin aerosol over-densities at different heights, and an extremely clean atmosphere. Weshow how the effective area of the telescope system is gradually reduced in the presence of varying concentrations of aerosols whereas the energy threshold rises. Clouds at different heights produce energy and altitude-dependent effects on the performance of the system.

  16. Inverse Modeling of Cloud – Aerosol Interactions

    OpenAIRE

    Partridge, Daniel

    2011-01-01

    The role of aerosols and clouds is one of the largest sources of uncertainty in understanding climate change. The primary scientific goal of this thesis is to improve the understanding of cloud-aerosol interactions by applying inverse modeling using Markov Chain Monte Carlo (MCMC) simulation. Through a set of synthetic tests using a pseudo-adiabatic cloud parcel model, it is shown that a self adaptive MCMC algorithm can efficiently find the correct optimal values of meteorological and aerosol...

  17. Microphysical Characterization of Aerosol Signatures over Greece

    OpenAIRE

    Akshath Sharma; Sampann Arora; Pranav Chandramouli; Costas Varotsos; Sat Ghosh; Archit Verma; Ishan Saini

    2016-01-01

    A detailed microphysical characterization is presented for aerosol spectra over three major areas over Greece, namely- the Area West of Crete (AWC), the Greater Thessaloniki area (GTA) and the Greater Athens Area (GAA) based on measurements made by Varotsos (2005). Aerosol size distributions along with cloud droplet concentrations were gathered from data collected from the Forward Scattering Spectrometer Probe (FSSP)-300 and Passive Cavity Aerosol Spectrometer Probe (PCASP)-100X flown on a Fa...

  18. Monodisperse Aerosol Particles in an Apartment

    Czech Academy of Sciences Publication Activity Database

    Ondráček, Jakub; Ondráčková, Lucie; Stavová, P.; Ždímal, Vladimír; Barták, M.; Smolík, Jiří

    Thessaloniki : Hellenic Association for Aerosol Research, 2008, T10A012P. [European Aerosol Conference 2008. Thessaloniki (GR), 24.08.2008-29.08.2008] R&D Projects: GA ČR GA101/07/1361 Institutional research plan: CEZ:AV0Z40720504 Keywords : indoor aerosols * dynamic characteristics * number size distribution Subject RIV: CF - Physical ; Theoretical Chemistry www.eac2008.org

  19. Pulmonary deposition and clearance of aerosolized interferon.

    OpenAIRE

    Wyde, P.R.; Wilson, S Z; M.J. Kramer; Sun, C S; Knight, V

    1984-01-01

    Small particle aerosols of a hybrid DNA recombinant human alpha interferon, A/D bgl, and a related DNA recombinant leukocyte interferon, A, were generated and delivered to mice for 23.5 h a day for 4 consecutive days. The antiviral activity of these interferons in delivery reservoirs, in the aerosols generated, and in the lungs of test mice was monitored during and after aerosol administration in cytopathic effect inhibition assays, using vesicular stomatitis virus as the indicator virus. In ...

  20. Nanoscale Polymeric Particles via Aerosol-Photopolymerization

    OpenAIRE

    Akgün, Ertan

    2015-01-01

    This PhD thesis focuses on the process of aerosol-photopolymerization for the generation of various polymeric particles. Such structures are most often prepared by liquid-based methods via the well-established thermal initiation step, and aerosol-photopolymerization is presented as an alternative, aerosol-based technique which employs photoinitiated polymerization. Discussed within this thesis are the advantages and broad aspects of the process.

  1. Aerosol from Organic Nitrogen in the Southeast United States

    Science.gov (United States)

    Biogenic volatile organic compounds (BVOCs) contribute significantly to organic aerosol in the southeastern United States. During the Southern Oxidant and Aerosol Study (SOAS), a portion of ambient organic aerosol was attributed to isoprene oxidation and organic nitrogen from BVO...

  2. Problemes methodologiques poses par l'extraction et la recuperation des bacteries telluriques pour leur quantification par immunofluorescence

    OpenAIRE

    Crozat, Y.; Cleyet-Marel, Jean Claude

    1984-01-01

    Afin d’améliorer la valeur quantitative de la technique de dénombrement des bactéries telluriques (Rhizobium japonicum) par immunofluorescence, on compare différents modes d’extraction et de récupération. L’utilisation de membranes en polycarbonates (Nucléopores) supprime les 40 p. 100 de pertes occasionnées par les membranes cellulosiques (Millipores) classiquement employées. Parmi les différents floculants testés, Ca(OH)2/MgCO3(2/5) permet d’obtenir les meilleurs résultats. Cependant po...

  3. Limitation des populations de ravageurs de l’olivier par le recours à la lutte biologique par conservation

    OpenAIRE

    Warlop, Francois

    2006-01-01

    L’olivier est une culture relativement rustique, mais qui peut être fortement attaquée par la mouche Bactrocera oleae (Gmelin), son principal ravageur. Les parasitoïdes de cette mouche sont connus, mais leur impact sur les populations de Diptères demeure faible, faute d’aménagement adéquat du paysage et suite à une intensification abusive des pratiques culturales. Le programme d’installation de bandes florales mené par le Groupe de recherches en agriculture biologique qui a débuté en 2004 vis...

  4. IGF-II receptors in luminal and basolateral membranes isolated from pars convoluta and pars recta of rabbit proximal tubule

    DEFF Research Database (Denmark)

    Jacobsen, Christian; Jessen, H; Flyvbjerg, A

    1995-01-01

    The binding of 125I-labeled insulin-like growth factor-II (125I-IGF-II) to luminal and basolateral membrane vesicles isolated from pars convoluta and the straight part (pars recta) of rabbit proximal tubule was investigated. Analyses of the binding data by use of the general stoichiometric binding...... inhibitory effect of beta-galactosidase. Analyses of 125I-IGF-II binding curves in the presence of beta-galactosidase or D-mannose 6-phosphate demonstrated that none of these compounds changed the binding affinity of 125I-IGF-II for the membrane vesicles. The IGF-II/M6P receptor content in the luminal...

  5. Aerosol observation in Fengtai area, Beijing

    Institute of Scientific and Technical Information of China (English)

    Zengdong Liu; Jianguo Liu; Bei Wang; Fan Lu; Shuhua Huang; Dexia Wu; Daowen Han

    2008-01-01

    Measurements of aerosol number concentration and particulate matter with diameter less than 10μm (PM10) mass concentrations of urban background aerosols were performed in Fengtai area, Beijing in 2006. Black carbon (BC) was collected simultaneously from the ground and analyzed to determine the particulate matter components. To satisfy the interest in continuous monitoring of temporal and spatial distribution of aerosols, the relationship between extinction coefficient (visibility) measured by lidar remote sensing and the aerosol number concentration measured from the ground was derived by using statistical method. Vertical particle number concentration profile within the planetary boundary layer could be inversed through the lidar data as well as the statistical relation.

  6. The fifth Finnish national aerosol symposium

    International Nuclear Information System (INIS)

    The Fifth Finnish Aerosol Symposium was held June 1-3, 1993. Symposium is jointly organized by FAAR, Aerosol Technology Group of Technical Research Centre of Finland and Helsinki University, Department of Physics. Aerosols, the suspensions of solid and liquid particles and gases, are receiving increasing importance in many areas of science and technology. These include industrial hygiene, ambient and indoor air pollution, pollution control technologies, cloud physics, nuclear safety engineering, combustion science and engineering, clean manufacturing technologies and material processing. The importance of aerosol issues during the development of advanced fuel conversion and material processing technologies can be realized when looking at the numerous papers presented on these topics at the Symposium

  7. The boiling point of stratospheric aerosols.

    Science.gov (United States)

    Rosen, J. M.

    1971-01-01

    A photoelectric particle counter was used for the measurement of aerosol boiling points. The operational principle involves raising the temperature of the aerosol by vigorously heating a portion of the intake tube. At or above the boiling point, the particles disintegrate rather quickly, and a noticeable effect on the size distribution and concentration is observed. Stratospheric aerosols appear to have the same volatility as a solution of 75% sulfuric acid. Chemical analysis of the aerosols indicates that there are other substances present, but that the sulfate radical is apparently the major constituent.

  8. SPM analysis of single aerosol particles

    International Nuclear Information System (INIS)

    Aerosol samples were collected using Anderson cascade impact samplers and the dispersed single aerosol particles were embedded in thin PVDF films. A group of single aerosol particles distributed in an area of 180 μm x 150 μm was analyzed by the scanning proton microprobe (SPM). The distributions of 12 elements in the group were mapped with the three dimensional contour technique. Air pollution sources were then analyzed in some details. It is shown that analysis of the group of single aerosol particles by SPM may become a new approach to the study of air pollution

  9. A mathematical model of aerosol holding chambers

    DEFF Research Database (Denmark)

    Zak, M; Madsen, J; Berg, E;

    1999-01-01

    A mathematical model of aerosol delivery from holding chambers (spacers) was developed incorporating tidal volume (VT), chamber volume (Vch), apparatus dead space (VD), effect of valve insufficiency and other leaks, loss of aerosol by immediate impact on the chamber wall, and fallout of aerosol......-mentioned factors, initial loss of aerosol by impact on the chamber wall is most important for the efficiency of a spacer. With a VT of 195 mL, the AeroChamber and Babyhaler were emptied in two breaths, the NebuChamber in four breaths, and the Nebuhaler in six breaths. Insufficiencies of the expiratory valves were...

  10. The Aerosol/Cloud/Ecosystems Mission (ACE)

    Science.gov (United States)

    Schoeberl, Mark

    2008-01-01

    The goals and measurement strategy of the Aerosol/Cloud/Ecosystems Mission (ACE) are described. ACE will help to answer fundamental science questions associated with aerosols, clouds, air quality and global ocean ecosystems. Specifically, the goals of ACE are: 1) to quantify aerosol-cloud interactions and to assess the impact of aerosols on the hydrological cycle and 2) determine Ocean Carbon Cycling and other ocean biological processes. It is expected that ACE will: narrow the uncertainty in aerosol-cloud-precipitation interaction and quantify the role of aerosols in climate change; measure the ocean ecosystem changes and precisely quantify ocean carbon uptake; and, improve air quality forecasting by determining the height and type of aerosols being transported long distances. Overviews are provided of the aerosol-cloud community measurement strategy, aerosol and cloud observations over South Asia, and ocean biology research goals. Instruments used in the measurement strategy of the ACE mission are also highlighted, including: multi-beam lidar, multiwavelength high spectra resolution lidar, the ocean color instrument (ORCA)--a spectroradiometer for ocean remote sensing, dual frequency cloud radar and high- and low-frequency micron-wave radiometer. Future steps for the ACE mission include refining measurement requirements and carrying out additional instrument and payload studies.

  11. Limitation on electrical measures of aerosols

    International Nuclear Information System (INIS)

    Based upon the assumption that there is a constant, natural, background ion source, atmospheric conductivity has been used as a measure of the presence of aerosol particles because such particles remove the effective charge carriers from the atmosphere. Another variety of electrical measure is the total charge acquired by the aerosol under either natural or artificial charging conditions. Currently, the most widely cited electrical method for aerosol size distribution analysis is the diffusion charging mobility analysis method in which the electrical current due to the controlled unipolar charging of the aerosol is measured while increasing mobility fractions of that aerosol are removed. The hypothesis is that by monitoring the diminution of aerosol current as a function of the known particle electrical mobilities removed, a measure of the aerosol size distribution is derived. Fundamental to all such measures of aerosol size is the assumption that any aerosol can be put in a well-defined charge state. This note presents an examination of that assumption

  12. Topics in current aerosol research (part2)

    CERN Document Server

    Hidy, G M

    1972-01-01

    Topics in Current Aerosol Research, Part 2 contains some selected articles in the field of aerosol study. The chosen topics deal extensively with the theory of diffusiophoresis and thermophoresis. Also covered in the book is the mathematical treatment of integrodifferential equations originating from the theory of aerosol coagulation. The book is the third volume of the series entitled International Reviews in Aerosol Physics and Chemistry. The text offers significant understanding of the methods employed to develop a theory for thermophoretic and diffusiophoretic forces acting on spheres in t

  13. Is aerosol formation in cirrus clouds possible?

    Directory of Open Access Journals (Sweden)

    J. Kazil

    2007-01-01

    Full Text Available The recent observation of ultrafine aerosol particles in cirrus clouds has raised the question whether aerosol formation within cirrus clouds is possible, and if so, what mechanisms are involved. We have developed an aerosol parcel model of neutral and charged H2SO4/H2O aerosol processes, including nucleation from the gas phase and loss onto cirrus ice particles. Laboratory thermodynamic data for sulfuric acid uptake and loss by small neutral and charged clusters are used, allowing for a reliable description of both neutral and charged nucleation down to the very low temperatures occurring in the upper troposphere and lower stratosphere. The model implements a first order scheme for resolving the aerosol size distribution within its geometric size sections, which efficiently suppresses numerical diffusion. We operate the model offline on trajectories generated with a detailed 1D cirrus model which describes ice crystal nucleation, deposition growth, vertical advection of ice crystals and water vapor, and ice crystal sedimentation. In this paper we explore the possibility of aerosol formation within non-convective cirrus clouds and draw conclusions for aerosol formation in anvil cirrus. We find that sulfate aerosol formation within cirrus clouds can proceed even at high ice surface area concentrations, and depends strongly on the size of the cirrus ice crystals and on the surface area concentration of preexisting aerosol particles.

  14. SMEX02 Atmospheric Aerosol Optical Properties Data

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set consists of observations of atmospheric parameters including spectral aerosol optical depths, precipitable water, sky radiance distributions and...

  15. Detailed Aerosol Characterization using Polarimetric Measurements

    Science.gov (United States)

    Hasekamp, Otto; di Noia, Antonio; Stap, Arjen; Rietjens, Jeroen; Smit, Martijn; van Harten, Gerard; Snik, Frans

    2016-04-01

    Anthropogenic aerosols are believed to cause the second most important anthropogenic forcing of climate change after greenhouse gases. In contrast to the climate effect of greenhouse gases, which is understood relatively well, the negative forcing (cooling effect) caused by aerosols represents the largest reported uncertainty in the most recent assessment of the International Panel on Climate Change (IPCC). To reduce the large uncertainty on the aerosol effects on cloud formation and climate, accurate satellite measurements of aerosol optical properties (optical thickness, single scattering albedo, phase function) and microphysical properties (size distribution, refractive index, shape) are essential. There is growing consensus in the aerosol remote sensing community that multi-angle measurements of intensity and polarization are essential to unambiguously determine all relevant aerosol properties. This presentations adresses the different aspects of polarimetric remote sensing of atmospheric aerosols, including retrieval algorithm development, validation, and data needs for climate and air quality applications. During past years, at SRON-Netherlands Instite for Space Research retrieval algorithms have been developed that make full use of the capabilities of polarimetric measurements. We will show results of detailed aerosol properties from ground-based- (groundSPEX), airborne- (NASA Research Scanning Polarimeter), and satellite (POLDER) measurements. Also we will discuss observational needs for future instrumentation in order to improve our understanding of the role of aerosols in climate change and air quality.

  16. Multi-Sensor Aerosol Products Sampling System

    Science.gov (United States)

    Petrenko, M.; Ichoku, C.; Leptoukh, G.

    2011-01-01

    Global and local properties of atmospheric aerosols have been extensively observed and measured using both spaceborne and ground-based instruments, especially during the last decade. Unique properties retrieved by the different instruments contribute to an unprecedented availability of the most complete set of complimentary aerosol measurements ever acquired. However, some of these measurements remain underutilized, largely due to the complexities involved in analyzing them synergistically. To characterize the inconsistencies and bridge the gap that exists between the sensors, we have established a Multi-sensor Aerosol Products Sampling System (MAPSS), which consistently samples and generates the spatial statistics (mean, standard deviation, direction and rate of spatial variation, and spatial correlation coefficient) of aerosol products from multiple spacebome sensors, including MODIS (on Terra and Aqua), MISR, OMI, POLDER, CALIOP, and SeaWiFS. Samples of satellite aerosol products are extracted over Aerosol Robotic Network (AERONET) locations as well as over other locations of interest such as those with available ground-based aerosol observations. In this way, MAPSS enables a direct cross-characterization and data integration between Level-2 aerosol observations from multiple sensors. In addition, the available well-characterized co-located ground-based data provides the basis for the integrated validation of these products. This paper explains the sampling methodology and concepts used in MAPSS, and demonstrates specific examples of using MAPSS for an integrated analysis of multiple aerosol products.

  17. Simplified aerosol modeling for variational data assimilation

    Directory of Open Access Journals (Sweden)

    F. Chevallier

    2009-06-01

    Full Text Available We have developed a simplified aerosol model together with its tangent linear and adjoint versions for variational assimilation of aerosol optical depth with the aim to optimize aerosol emissions over the globe. The model was derived from the general circulation model LMDz; it groups together the 24 aerosol species simulated in LMDz into 4 species, namely gaseous precursors, fine mode aerosols, coarse mode desert dust and coarse mode sea salt. The emissions have been kept as in the original model. Modifications, however, were introduced in the computation of aerosol optical depth and in the processes of sedimentation, dry and wet deposition and sulfur chemistry to ensure consistency with the new set of species and their composition.

    The simplified model successfully manages to reproduce the main features of the aerosol distribution in LMDz. Differences between the original and simplified models are mainly associated to the new deposition and sedimentation velocities consistent with the definition of species in the simplified model and the simplification of the sulfur chemistry. Furthermore, simulated aerosol optical depth remains within the variability of AERONET observations for all aerosol types and all sites throughout most of the year.

    Sensitivity analyses with the tangent linear version show that the simplified sulfur chemistry is the dominant process responsible for the strong non-linearity of the model.

  18. A global aerosol classification algorithm incorporating multiple satellite data sets of aerosol and trace gas abundances

    Science.gov (United States)

    Penning de Vries, M. J. M.; Beirle, S.; Hörmann, C.; Kaiser, J. W.; Stammes, P.; Tilstra, L. G.; Tuinder, O. N. E.; Wagner, T.

    2015-09-01

    Detecting the optical properties of aerosols using passive satellite-borne measurements alone is a difficult task due to the broadband effect of aerosols on the measured spectra and the influences of surface and cloud reflection. We present another approach to determine aerosol type, namely by studying the relationship of aerosol optical depth (AOD) with trace gas abundance, aerosol absorption, and mean aerosol size. Our new Global Aerosol Classification Algorithm, GACA, examines relationships between aerosol properties (AOD and extinction Ångström exponent from the Moderate Resolution Imaging Spectroradiometer (MODIS), UV Aerosol Index from the second Global Ozone Monitoring Experiment, GOME-2) and trace gas column densities (NO2, HCHO, SO2 from GOME-2, and CO from MOPITT, the Measurements of Pollution in the Troposphere instrument) on a monthly mean basis. First, aerosol types are separated based on size (Ångström exponent) and absorption (UV Aerosol Index), then the dominating sources are identified based on mean trace gas columns and their correlation with AOD. In this way, global maps of dominant aerosol type and main source type are constructed for each season and compared with maps of aerosol composition from the global MACC (Monitoring Atmospheric Composition and Climate) model. Although GACA cannot correctly characterize transported or mixed aerosols, GACA and MACC show good agreement regarding the global seasonal cycle, particularly for urban/industrial aerosols. The seasonal cycles of both aerosol type and source are also studied in more detail for selected 5° × 5° regions. Again, good agreement between GACA and MACC is found for all regions, but some systematic differences become apparent: the variability of aerosol composition (yearly and/or seasonal) is often not well captured by MACC, the amount of mineral dust outside of the dust belt appears to be overestimated, and the abundance of secondary organic aerosols is underestimated in comparison

  19. PH motifs in PAR1&2 endow breast cancer growth.

    Science.gov (United States)

    Kancharla, A; Maoz, M; Jaber, M; Agranovich, D; Peretz, T; Grisaru-Granovsky, S; Uziely, B; Bar-Shavit, R

    2015-01-01

    Although emerging roles of protease-activated receptor1&2 (PAR1&2) in cancer are recognized, their underlying signalling events are poorly understood. Here we show signal-binding motifs in PAR1&2 that are critical for breast cancer growth. This occurs via the association of the pleckstrin homology (PH) domain with Akt/PKB as a key signalling event of PARs. Other PH-domain signal-proteins such as Etk/Bmx and Vav3 also associate with PAR1 and PAR2 through their PH domains. PAR1 and PAR2 bind with priority to Etk/Bmx. A point mutation in PAR2, H349A, but not in R352A, abrogates PH-protein association and is sufficient to markedly reduce PAR2-instigated breast tumour growth in vivo and placental extravillous trophoblast (EVT) invasion in vitro. Similarly, the PAR1 mutant hPar1-7A, which is unable to bind the PH domain, reduces mammary tumours and EVT invasion, endowing these motifs with physiological significance and underscoring the importance of these previously unknown PAR1 and PAR2 PH-domain-binding motifs in both pathological and physiological invasion processes. PMID:26600192

  20. Par Pond vegetation status summer 1995 - July survey descriptive summary

    International Nuclear Information System (INIS)

    A survey of the emergent shoreline aquatic plant, communities began in June 1995, three months after the refilling of Par Pond to approximately 200 feet (61 meters) above mean sea level, and continued with this July survey. Aquatic plant communities, similar to the pre-drawdown Par Pond communities, are becoming reestablished. Beds of maidencane (Panicum hemitomon), lotus (Nelumbo lutea), water lily (Nymphaea odorata), and watershield (Brasenia schreberi) are now extensive and well established. In addition, within isolated coves, extensive beds of water lilies and spike-rush (Eleocharis sp.) are common. Cattail occurrence has increased since refill, but large beds common to Par Pond prior to the drawdown have not formed. Invasion of willow (Salix sp.) and red maple (Acer rubrum) occurred along the lake shoreline during drawdown. The red maples along the present shoreline are beginning to show evidence of stress and mortality from flooding over the past four months. Some of the willows appear to be stressed as well. The loblolly pines (Pinus taeda), which were flooded in all but the shallow shoreline areas, are now dead. Future surveys are planned for the growing seasons of 1995, 1996, and 1997, along with the evaluation of satellite data for mapping the areal extent of the macrophyte beds of Par Pond

  1. Radiative Transfer Code: Application to the calculation of PAR

    Indian Academy of Sciences (India)

    D Emmanuel; D Phillippe; C Malik

    2000-12-01

    The production of carbon in the ocean, the so-called primary production, depends on various physico- biological parameters: the biomass and nutrient amounts in oceans, the salinity and temperature of the water and the light available in the water column. We focus on the visible spectrum of the solar radiation defined as the Photosynthetically Active Radiation (PAR). We developed a model (Chami et al. 1997) to simulate the behavior of the solar beam in the atmosphere and the ocean. We first describe the theoretical basis of the code and the method we used to solve the radiative transfer equation (RTE): the successive orders of scattering (SO). The second part deals with a sensitivity study of the PAR just above and below the sea surface for various atmospheric conditions. In a cloudy sky, we computed a ratio between vector fluxes just above the sea surface and spherical fluxes just beneath the sea surface. When the optical thickness of the cloud increases this ratio remains constant and around 1.29. This parameter is convenient to convert vector flux at the sea surface as retrieved from satellite to PAR. Subsequently, we show how solar radiation as vector flux rather than PAR leads to an underestimate of the primary production up to 40% for extreme cases.

  2. uPAR as anti-cancer target

    DEFF Research Database (Denmark)

    Lund, Ida K; Illemann, Martin; Thurison, Tine;

    2011-01-01

    Degradation of proteins in the extracellular matrix is crucial for the multistep process of cancer invasion and metastasis. Compelling evidence has demonstrated the urokinase receptor (uPAR) and its cognate ligand, the urokinase plasminogen activator (uPA), to play critical roles in the concerted...

  3. Radiological impact of Par Pond drawdown from liquid effluent pathways

    International Nuclear Information System (INIS)

    The water level of Par Pond has been lowered over the past several months to reduce the effects in the event of catastrophic dam failure while assessing the condition of the dam and determining if repairs are necessary. In lowering the level of Par Pond, 60 billion liters of water containing low levels of tritium and cesium-137 were discharged to several onsite streams. SRS surface streams flow to the Savannah River. An assessment made to determine the total amount of tritium and Cs-137 discharged and to estimate the consequences to downstream Savannah River users. It is estimated that a total of 160 curies of tritium were displaced from Par Pond to the Savannah River between June 28, 1991 and September 19, 1991. This release could hypothetically result in a maximum individual dose of 3. 2x10-4 mrem and a total (80-km and drinking water populations) population dose of 1.4x10-2 person-rem. Likewise, a maximum individual dose of 5.0x10-2 mrem and a total population dose of 1.7x10-1 person- rem are predicted as a result of an estimated 0.21 curies of Cs-137 being discharged from Par Pond to the Savannah River

  4. Pollution par les nitrates: quels remèdes?

    OpenAIRE

    Zilliox, Lothaire; Schenck, Charles; Kobus, Helmut; Huwe, Bernd

    1990-01-01

    Au cours des dix dernières années, la pollution des eaux souterraines par les nitrates n'a cessé d'augmenter. Principale accussée: l'agriculture, l'application de méthodes de techniques culturales devrait permettre une meilleure gestion des engrais azotés.

  5. La lecture de Merleau-Ponty par Renaud Barbaras

    Czech Academy of Sciences Publication Activity Database

    Pechar, Jiří

    2015-01-01

    Roč. 11, č. 2 (2015). ISSN 1336-6556 Institutional support: RVO:67985955 Keywords : Merleau-Ponty * Husserl * phenomenology * linguistics of Ferdinand de Saussure Subject RIV: AA - Philosophy ; Religion http://www.ostium.sk/sk/la-lecture-de-merleau-ponty-par-renaud-barbaras/

  6. Den eneste ene - hvordan etniske minoritetsunge i Danmark danner par

    DEFF Research Database (Denmark)

    Singla, Rashmi

    Rapporten handler om etniske unges måde at danne par på. Rapporten er baseret på en større empirisk undersøgelse gennemført af forfatteren i 2003 og er desuden inspireret af forfatterens egen ph.d.-afhandling: "Ungdom, etnicitet og psychosocial intervention" (2000, Københavns Universitet). Rappor...

  7. Predicting spectral and PAR light attenuation in Greenlandic coastal waters

    DEFF Research Database (Denmark)

    Murray, Ciarán; Markager, Stiig; Stedmon, Colin

    present models for spectral and PAR (photosynthetically active radiation) attenuation in two contrasting Greenlandic fjords, Godthåbsfjord (SW Greenland) and Young Sound (NE Greenland). The fjords differ in the character and concentrations of optically active components present: dissolved organic material...

  8. Development of quantitative RT-PCR assays for wild-type urokinase receptor (uPAR-wt) and its splice variant uPAR-del5

    International Nuclear Information System (INIS)

    The receptor for the serine protease urokinase-type plasminogen activator, uPAR (CD 87), plays an important role in tumor cell invasion and metastasis of solid malignant tumors. uPAR is a highly glycosylated, glycan lipid-anchored membrane protein, consisting of three homologous domains. Each individual domain is encoded by two exons: DI by exons 2+3, DII by exons 4+5, and DIII by exons 6+7. Beside the wild-type (wt) uPAR mRNA, two splice variants either lacking exon 5 (uPAR-del5) or both exons 4 and 5 (uPARdel4/ 5) have been described. Previously, we studied expression of the mRNA variant uPAR-del4/5 and uPAR mRNA encompassing exons 2, 3, and 4 (i.e. uPAR-wt plus uPAR-del5) applying real-time RT-PCR assays for quantification of the mRNA concentration. In the present paper, we established two additional specific, robust and highly sensitive RT-PCR assays, based on the LightCycler technology, to specifically quantify either uPAR-wt or its splice variant, uPARdel5. Expression of uPAR-wt and uPAR-del5 was analyzed in different human malignant cell lines (ovarian cancer cell lines OVMZ-6 and OVMZ-10; breast cancer cell lines MDA-MB 231, MDA-MB 231 BAG, MDA-MB 435, and aMCF-7; brain tumor cell line LN 18) as well as in a set of 174 breast cancer tissue samples. uPAR-del5 mRNA was found to be expressed very frequently at a rather low level (typically less than 1% of uPAR-wt mRNA). In tumor tissue from breast cancer patients, a statistically significant correlation between uPAR-del5 and uPAR-wt mRNA (r = 0.779; P < 0.001) was observed. There was no association between the expression level of either mRNA and clinical parameters such as nodal status, tumor size and grade. In estrogen receptor negative tumors, a significantly higher uPAR-del5 expression was found (P 0.023). The two developed quantitative RT-PCR assays described here may aid further analysis of the function and clinical relevance of uPAR-wt and one of its splice variants, uPAR-del5, in malignant tumors

  9. The relationship between aerosol and cloud drop number concentrations in a global aerosol microphysics model

    Directory of Open Access Journals (Sweden)

    K. J. Pringle

    2009-06-01

    Full Text Available Empirical relationships that link cloud droplet number (CDN to aerosol number or mass are commonly used to calculate global fields of CDN for climate forcing assessments. In this work we use a sectional global model of sulfate and sea-salt aerosol coupled to a mechanistic aerosol activation scheme to explore the limitations of this approach. We find that a given aerosol number concentration produces a wide range of CDN concentrations due to variations in the shape of the aerosol size distribution. On a global scale, the dependence of CDN on the size distribution results in regional biases in predicted CDN (for a given aerosol number. Empirical relationships between aerosol number and CDN are often derived from regional data but applied to the entire globe. In an analogous process, we derive regional "correlation-relations" between aerosol number and CDN and apply these regional relations to calculations of CDN on the global scale. The global mean percentage error in CDN caused by using regionally derived CDN-aerosol relations is 20 to 26%, which is about half the global mean percentage change in CDN caused by doubling the updraft velocity. However, the error is as much as 25–75% in the Southern Ocean, the Arctic and regions of persistent stratocumulus when an aerosol-CDN correlation relation from the North Atlantic is used. These regions produce much higher CDN concentrations (for a given aerosol number than predicted by the globally uniform empirical relations. CDN-aerosol number relations from different regions also show very different sensitivity to changing aerosol. The magnitude of the rate of change of CDN with particle number, a measure of the aerosol efficacy, varies by a factor 4. CDN in cloud processed regions of persistent stratocumulus is particularly sensitive to changing aerosol number. It is therefore likely that the indirect effect will be underestimated in these important regions.

  10. The relationship between aerosol and cloud drop number concentrations in a global aerosol microphysics model

    Directory of Open Access Journals (Sweden)

    K. J. Pringle

    2009-01-01

    Full Text Available Empirical relationships that link cloud droplet number (CDN to aerosol number or mass are commonly used to calculate global fields of CDN for climate forcing assessments. In this work we use a sectional global model of sulfate and sea-salt aerosol coupled to a mechanistic aerosol activation scheme to explore the limitations of this approach. We find that a given aerosol number concentration produces a wide range of CDN concentrations due to variations in the shape of the aerosol size distribution. On a global scale, the dependence of CDN on the size distribution results in regional biases in predicted CDN (for a given aerosol number. Empirical relationships between aerosol number and CDN are often derived from regional data but applied to the entire globe. In an analogous process, we derive regional "correlation-relations" between aerosol number and CDN and apply these regional relations to calculations of CDN on the global scale. The global mean percentage error in CDN caused by using regionally derived CDN-aerosol relations is 20 to 26%, which is about half the global mean percentage change in CDN caused by doubling the updraft velocity. However, the error is as much as 25–75% in the Southern Ocean, the Arctic and regions of persistent stratocumulus when an aerosol-CDN correlation relation from the North Atlantic is used. These regions produce much higher CDN concentrations (for a given aerosol number than predicted by the globally uniform empirical relations. CDN-aerosol number relations from different regions also show very different sensitivity to changing aerosol. The magnitude of the rate of change of CDN with particle number, a measure of the aerosol efficacy, varies by a factor 4. CDN in cloud processed regions of persistent stratocumulus is particularly sensitive to changing aerosol number. It is therefore likely that the indirect effect will be underestimated in these important regions.

  11. The correlative method of industrial aerosol express-diagnostic

    International Nuclear Information System (INIS)

    The main difficulty of industrial aerosol control is absence of real-time data analysis methods for measurement quantities of a specific aerosol (for example, radioactive particles, beryllium aerosols, etc. This report is an attempt to establish a new experimental method for control of industrial aerosol pollution. The main idea of the method is to determine correlation dependences among the aerosol particle size distributions and quantities of specific aerosol particles in industrial pollutions, for which real-time control is very difficult. The possibility of specific aerosol control is suggested by means of aerosol size control. (author)

  12. Observation of attachment ratio of fission products on solution aerosol

    International Nuclear Information System (INIS)

    Attachment behavior of fission products to solution aerosols has been observed to elucidate the role of chemical effects in the generation mechanism of fissionproduct aerosols. Primary aerosols generated from aqueous solution of sodium chloride or ammonium sulfate were passed through a fission-product chamber, and radioactive aerosols were generated by attaching fission products to the primary aerosol particles. Attachment ratios of the fission products on aerosols were estimated from activity measurements. It was found that the attachment ratio of the sodium chloride solution aerosol is larger than that of the ammonium sulfate solution aerosol. (author)

  13. Improved global aerosol datasets for 2008 from Aerosol_cci

    Science.gov (United States)

    Holzer-Popp, Thomas; de Leeuw, Gerrit

    2013-04-01

    Within the ESA Climate Change Initiative (CCI) the Aerosol_cci project has meanwhile produced and validated global datasets from AATSR, PARASOL, MERIS, OMI and GOMOS for the complete year 2008. Whereas OMI and GOMOS were used to derive absorbing aerosol index and stratospheric extinction profiles, respectively, Aerosol Optical Depth (AOD) and Angstrom coefficient were retrieved from the three nadir sensors. For AATSR three algorithms were applied. AOD validation was conducted against AERONET sun photometer observations also in comparison to MODIS and MISR datasets. Validation included level2 (pixel level) and level3 (gridded daily) datasets. Several validation metrices were used and in some cases developed further in order to comprehensively evaluate the capabilities and limitations of the datasets. The metrices include standard statistical quantities (bias, rmse, Pearson correlation, linear regression) as well as scoring approaches to quantitatively assess the spatial and temporal correlations against AERONET. Over open ocean also MAN data were used to better constrain the aerosol background, but in 2008 had limited coverage. The validation showed that the PARASOL (ocean only) and AATSR (land and ocean) datasets have improved significantly and now reach the quality level and sometimes even go beyond the level of MODIS and MISR. However, the coverage of these European datasets is weaker than the one of the NASA datasets due to smaller instrument swath width. The MERIS dataset provides better coverage but has lower quality then the other datasets. A detailed regional and seasonal analysis revealed the strengths and weaknesses of each algorithm. Also, Angstrom coefficient was validated and showed encouraging results (more detailed aerosol type information provided in particular from PARASOL was not yet evaluated further). Additionally, pixel uncertainties contained in each dataset were statistically assessed which showed some remaining issues but also the added value

  14. Retrieval of Aerosol Height with TROPOMI

    Science.gov (United States)

    Sanders, A. F. J.; de Haan, J. F.; Veefkind, J. P.

    2012-04-01

    The Tropospheric Monitoring Instrument (TROPOMI), to be launched in 2015, will feature a new aerosol product providing the height of aerosol layers. Aerosol Layer Height will be one of two aerosol products, the other one being the Absorbing Aerosol Index. TROPOMI is a UV-VIS-NIR imaging spectrometer with daily global coverage. It will be part of ESA's Sentinel-5 Precursor mission. Algorithm development for the aerosol height product is currently underway at KNMI. In this presentation we will introduce the algorithm, highlight some of the development issues and discuss possible applications and example aerosol cases. Aerosol height observations from the near-infrared wavelength range will improve retrieval of other aerosol properties, particularly retrieval of absorption optical thickness. An increase in absorption in the ultraviolet wavelength range can be due to a higher imaginary part of the refractive index or to the aerosol layer being at a higher altitude. Independent height observations will therefore further constrain retrieval of the single scattering albedo. Furthermore, aerosol profile information is an important parameter when estimating radiative forcings and climate impacts of aerosol, it is a significant source of uncertainty in trace gas retrieval and it helps in understanding atmospheric transport mechanisms. Finally, timely available, global observations of aerosol height will be of interest to aviation safety agencies. The retrieval algorithm for aerosol height will be based on absorption by oxygen in the A-band (759-770 nm). Aerosols are assumed to be contained in a single layer. A spectral fit of reflectance (resolution 0.5 nm) across the absorption band provides layer height. The retrieval method will be optimal estimation to ensure a proper error analysis. Sensitivity studies have indicated that accuracy and precision of retrieved height for cloud-free scenes will be well below the TROPOMI science requirements (1 km). They have also shown that

  15. Characterization of aerosols produced by surgical procedures

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, H.C.; Muggenburg, B.A.; Lundgren, D.L.; Guilmette, R.A.; Snipes, M.B.; Jones, R.K. [Inhalation Toxicology Research Institute, Albuquerque, NM (United States); Turner, R.S. [Lovelace Health Systems, Albuquerque, NM (United States)

    1994-07-01

    In many surgeries, especially orthopedic procedures, power tools such as saws and drills are used. These tools may produce aerosolized blood and other biological material from bone and soft tissues. Surgical lasers and electrocautery tools can also produce aerosols when tissues are vaporized and condensed. Studies have been reported in the literature concerning production of aerosols during surgery, and some of these aerosols may contain infectious material. Garden et al. (1988) reported the presence of papilloma virus DNA in the fumes produced from laser surgery, but the infectivity of the aerosol was not assessed. Moon and Nininger (1989) measured the size distribution and production rate of emissions from laser surgery and found that particles were generally less than 0.5 {mu}m diameter. More recently there has been concern expressed over the production of aerosolized blood during surgical procedures that require power tools. In an in vitro study, the production of an aerosol containing the human immunodeficiency virus (HIV) was reported when power tools were used to cut tissues with blood infected with HIV. Another study measured the size distribution of blood aerosols produced by surgical power tools and found blood-containing particles in a number of size ranges. Health care workers are anxious and concerned about whether surgically produced aerosols are inspirable and can contain viable pathogens such as HIV. Other pathogens such as hepatitis B virus (HBV) are also of concern. The Occupational Safety and Health funded a project at the National Institute for Inhalation Toxicology Research Institute to assess the extent of aerosolization of blood and other tissues during surgical procedures. This document reports details of the experimental and sampling approach, methods, analyses, and results on potential production of blood-associated aerosols from surgical procedures in the laboratory and in the hospital surgical suite.

  16. Potential climatic effects of anthropogenic aerosols

    International Nuclear Information System (INIS)

    Aerosols act as part of the climate system through their influence on solar and terrestrial radiation. The effect of anthropogenic aerosols on the reduction of visibility is explored in this chapter. Elemental carbon has been identified as the most effective visibility-reducing species. Most of the visibility reduction is due to particles with diameter smaller than 2.5 μm. Studies indicate that sulfate is also a very important aerosol species that results in low visibility and high turbidity. Radiative properties such as aerosol single-scattering albedo values and absorption-to-backscatter ratios purported to produce warming or cooling effects of aerosols are discussed. It is concluded that aerosol clouds have a tendency to cool when they are over a low-albedo surface and have a tendency to warm when they are over high-albedo surfaces such as snow. Anthropogenic aerosols have a tendency to warm the earth's atmospheric system, based on calculations and assumed aerosol optical properties. However, this effect is somewhat offset by the absorption and re-emission into space of infrared terrestrial radiation. The net effect depends on the ratio of the absorption coefficients in the visible and infrared and also on the surface albedo. The effects on infrared radiation are documented for two anthropogenic aerosol sources in the United States, the Denver metropolitan area and power plant plumes in New Mexico, through calculations and measurements. Measured cooling rates within an aerosol plume are not sufficient to offset the warming rate due to absorption of short-wave radiation. Research indicates that anthropogenic aerosols can possibly cause local-scale warming of the atmosphere, but global-scale climatic effects remain an open question

  17. Detection of suPAR in the Saliva of Healthy Young Adults: Comparison with Plasma Levels

    OpenAIRE

    Anna Gustafsson; Vjosa Ajeti; Lennart Ljunggren

    2011-01-01

    The soluble urokinase plasminogen activator receptor (suPAR) has been detected in blood, plasma, serum, urine, ovarian cystic fluid, and cerebrospinal fluid. Elevated suPAR levels in plasma have been associated with negative outcomes in various diseases, such as bacteremia, sepsis, SIRS, cardiovascular disease, cancer, and tuberculosis. The primary aim of this study was to investigate whether suPAR can be detected in saliva from healthy individuals and thus, if saliva suPAR can be related to ...

  18. Remote sensing of aerosol in the terrestrial atmosphere from space: "AEROSOL-UA" mission

    Science.gov (United States)

    Yatskiv, Yaroslav; Milinevsky, Gennadi; Degtyarev, Alexander

    2016-07-01

    The distribution and properties of atmospheric aerosols on a global scale are not well known in terms of determination of their effects on climate. This mostly is due to extreme variability of aerosol concentrations, properties, sources, and types. Aerosol climate impact is comparable to the effect of greenhouse gases, but its influence is more difficult to measure, especially with respect to aerosol microphysical properties and the evaluation of anthropogenic aerosol effect. There are many satellite missions studying aerosol distribution in the terrestrial atmosphere, such as MISR/Terra, OMI/Aura, AVHHR, MODIS/Terra and Aqua, CALIOP/CALIPSO. To improve the quality of data and climate models, and to reduce aerosol climate forcing uncertainties, several new missions are planned. The gap in orbital instruments for studying aerosol microphysics has arisen after the Glory mission failed during launch in 2011. In this review paper, we describe several planned aerosol space missions, including the Ukrainian project AEROSOL-UA that will obtain the data using a multi-channel scanning polarimeter and wide-angle polarimetric camera. The mission is designed for remote sensing of the aerosol microphysics and cloud properties on a global scale.

  19. Aerosol retrieval algorithm for the characterization of local aerosol using MODIS L1B data

    International Nuclear Information System (INIS)

    Atmospheric aerosol plays an important role in radiation budget, climate change, hydrology and visibility. However, it has immense effect on the air quality, especially in densely populated areas where high concentration of aerosol is associated with premature death and the decrease of life expectancy. Therefore, an accurate estimation of aerosol with spatial distribution is essential, and satellite data has increasingly been used to estimate aerosol optical depth (AOD). Aerosol product (AOD) from Moderate Resolution Imaging Spectroradiometer (MODIS) data is available at global scale but problems arise due to low spatial resolution, time-lag availability of AOD product as well as the use of generalized aerosol models in retrieval algorithm instead of local aerosol models. This study focuses on the aerosol retrieval algorithm for the characterization of local aerosol in Hong Kong for a long period of time (2006-2011) using high spatial resolution MODIS level 1B data (500 m resolution) and taking into account the local aerosol models. Two methods (dark dense vegetation and MODIS land surface reflectance product) were used for the estimation of the surface reflectance over land and Santa Barbara DISORT Radiative Transfer (SBDART) code was used to construct LUTs for calculating the aerosol reflectance as a function of AOD. Results indicate that AOD can be estimated at the local scale from high resolution MODIS data, and the obtained accuracy (ca. 87%) is very much comparable with the accuracy obtained from other studies (80%-95%) for AOD estimation

  20. Detection of suPAR in the Saliva of Healthy Young Adults: Comparison with Plasma Levels

    Science.gov (United States)

    Gustafsson, Anna; Ajeti, Vjosa; Ljunggren, Lennart

    2011-01-01

    The soluble urokinase plasminogen activator receptor (suPAR) has been detected in blood, plasma, serum, urine, ovarian cystic fluid, and cerebrospinal fluid. Elevated suPAR levels in plasma have been associated with negative outcomes in various diseases, such as bacteremia, sepsis, SIRS, cardiovascular disease, cancer, and tuberculosis. The primary aim of this study was to investigate whether suPAR can be detected in saliva from healthy individuals and thus, if saliva suPAR can be related to plasma suPAR, CRP, BMI, or gender. Blood and unstimulated whole saliva was collected from 20 healthy individuals (10 female and 10 male, median age of 28 years; range 21–41). CRP and suPAR were measured with ELISA in saliva and serum/plasma. suPAR was detected in all saliva samples in the 5.2–28.1 ng/mL range, with a median value of 17.1 ng/mL. Saliva suPAR was significantly higher (P < 0.001) but not correlated to plasma suPAR in healthy young adults with normal plasma suPAR levels. suPAR and CRP levels were correlated in blood but not in saliva. No correlation was found between BMI, age, or gender and suPAR in saliva. PMID:22084570

  1. Intact and cleaved uPAR forms: diagnostic and prognostic value in cancer

    DEFF Research Database (Denmark)

    Rasch, M.G.; Lund, I.K.; Hoyer-Hansen, G.;

    2008-01-01

    identified in tissue and body fluids. It is well-established, that the total amount of all uPAR forms is a strong prognostic marker in different types of cancer. Using immunoassays, measuring the individual uPAR forms, has revealed that the cleaved uPAR forms are even stronger prognostic markers and have...

  2. ParA resolvase catalyzes site-specific excision of DNA from the Arabidopsis genome

    Science.gov (United States)

    The small serine resolvase ParA from bacterial plasmids RK2 and RP4 catalyzes the recombination of two identical 133 bp recombination sites known as MRS. Previously, we reported that ParA is active in the fission yeast Schizosaccharomyces pombe. In this work, the parA recombinase gene was placed un...

  3. The urokinase receptor (uPAR) facilitates clearance of Borrelia burgdorferi

    NARCIS (Netherlands)

    J.W.R. Hovius; M.F. Bijlsma; G.J.W. van der Windt; W.J. Wiersinga; B.J.D. Boukens; J. Coumou; A. Oei; R. de Beer; A.F. de Vos; C. van 't Veer; A.P. van Dam; P. Wang; E. Fikrig; M.M. Levi; J.J.T.H. Roelofs; T. van der Poll

    2009-01-01

    The causative agent of Lyme borreliosis, the spirochete Borrelia burgdorferi, has been shown to induce expression of the urokinase receptor (uPAR); however, the role of uPAR in the immune response against Borrelia has never been investigated. uPAR not only acts as a proteinase receptor, but can also

  4. First (18)F-labeled ligand for PET imaging of uPAR

    DEFF Research Database (Denmark)

    Persson, Morten; Liu, Hongguang; Madsen, Jacob;

    2013-01-01

    Urokinase-type plasminogen activator receptor (uPAR) is overexpressed in human prostate cancer and uPAR has been found to be associated with metastatic disease and poor prognosis. AE105 is a small linear peptide with high binding affinity to uPAR. We synthesized an N-terminal NOTA...

  5. Is There an "F" in Your PAR? Understanding, Teaching and Doing Action Research

    Science.gov (United States)

    Lorenzetti, Liza; Walsh, Christine Ann

    2014-01-01

    Participatory Action Research (PAR) is increasingly recognized within academic research and pedagogy. What are the benefits of including feminism within participatory action research and teaching? In responding to this question, we discuss the similarities and salient differences between PAR and feminist informed PAR (FPAR). There are eight themes…

  6. Atmospheric Aerosols in the Suburb of Prague

    Czech Academy of Sciences Publication Activity Database

    Matějková, Daniela; Ždímal, Vladimír; Schwarz, Jaroslav; Smolík, Jiří

    -: -, 2009, T051A30. [European Aerosol Conference 2009. Karlsruhe (DE), 06.09.2009-11.09.2009] Grant ostatní: MF CZ:(FI) 0049 Institutional research plan: CEZ:AV0Z40720504 Keywords : atmospheric aerosols * particle formation * particle size distribution Subject RIV: CF - Physical ; Theoretical Chemistry

  7. Automated mobility-classified-aerosol detector

    OpenAIRE

    Russell, Lynn M.; Flagan, Richard C.; Zhang, Shou-Hua

    2001-01-01

    An aerosol detection system for measuring particle number distribution with respect to particle dimension in an aerosol sample. The system includes an alternating dual-bag sampler, a radially classified differential mobility analyzer, and a condensation nucleus counter. Pressure variations in sampling are compensated by feedback control of volumetric flow rates using a plurality of flow control elements.

  8. Aerosols Processes in the CMAQ Adjoint

    Czech Academy of Sciences Publication Activity Database

    Turner, M.; Henze, D.; Hakami, A.; Zhao, S.; Resler, Jaroslav; Carmichael, G.; Stanier, C.; Baek, J.; Saide, P.; Sandu, A.; Russel, A.; Jeong, G.; Nenes, A.; Capps, S.; Percell, P.; Pinder, R.; Napelenok, S.; Pye, H.; Bash, J.; Chai, T.; Byun, D

    Davis: Air Quality Research Center, 2011. [IAMA 2011. International Aerosol Modeling Algorithms Conference /3./. Davis, 30.11.2011-02.12.2011] Institutional research plan: CEZ:AV0Z10300504 Keywords : air pollution * adjoint * aerosols Subject RIV: DG - Athmosphere Sciences, Meteorology http://dl.dropbox.com/u/41967626/IAMApresent/TURNER.pdf

  9. Aerosols in science, medicine and technology

    International Nuclear Information System (INIS)

    In the conference opening address the applications of aerosol science to everyday life are listed, e.g. air pollution, airborn infections, climatic and weather effects, industrial processes and toxicology. The need for more investment in research, education and teaching in aerosol science is stressed. (UK)

  10. Atmospheric aerosol light scattering and polarization peculiarities

    CERN Document Server

    Patlashenko, Zh I

    2015-01-01

    This paper considers environmental problems of natural and anthropogenic atmospheric aerosol pollution and its global and regional monitoring. Efficient aerosol investigations may be achieved by spectropolarimetric measurements. Specifically second and fourth Stokes parameters spectral dependencies carry information on averaged refraction and absorption indexes and on particles size distribution functions characteristics.

  11. Evaluation of MERRAero (MERRA Aerosol Reanalysis)

    Science.gov (United States)

    Buchard, Virginie; da Silva, Arlindo; Randles, Cynthia; Colarco, Peter; Darmenov, Anton; Govindaraju, Ravi

    2016-01-01

    This presentation focuses on MERRA Aerosol Reanalysis (MERRAero) which is the first aerosol reanalysis produced at GMAO. This presentation involve an overview of MERRAero. The evaluation of MERRAero absorption and the evaluation of MERRAero Surface PM 2.5 will also be discussed.

  12. Characterization of urban aerosol in Cork city (Ireland using aerosol mass spectrometry

    Directory of Open Access Journals (Sweden)

    M. Dall'Osto

    2013-05-01

    Full Text Available Ambient wintertime background urban aerosol in Cork city, Ireland, was characterized using aerosol mass spectrometry. During the three-week measurement study in 2009, 93% of the ca. 1 350 000 single particles characterized by an Aerosol Time-of-Flight Mass Spectrometer (TSI ATOFMS were classified into five organic-rich particle types, internally mixed to different proportions with elemental carbon (EC, sulphate and nitrate, while the remaining 7% was predominantly inorganic in nature. Non-refractory PM1 aerosol was characterized using a High Resolution Time-of-Flight Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS and was also found to comprise organic aerosol as the most abundant species (62%, followed by nitrate (15%, sulphate (9% and ammonium (9%, and chloride (5%. Positive matrix factorization (PMF was applied to the HR-ToF-AMS organic matrix, and a five-factor solution was found to describe the variance in the data well. Specifically, "hydrocarbon-like" organic aerosol (HOA comprised 20% of the mass, "low-volatility" oxygenated organic aerosol (LV-OOA comprised 18%, "biomass burning" organic aerosol (BBOA comprised 23%, non-wood solid-fuel combustion "peat and coal" organic aerosol (PCOA comprised 21%, and finally a species type characterized by primary extit{m/z}~peaks at 41 and 55, similar to previously reported "cooking" organic aerosol (COA, but possessing different diurnal variations to what would be expected for cooking activities, contributed 18%. Correlations between the different particle types obtained by the two aerosol mass spectrometers are also discussed. Despite wood, coal and peat being minor fuel types used for domestic space heating in urban areas, their relatively low combustion efficiencies result in a significant contribution to PM1 aerosol mass (44% and 28% of the total organic aerosol mass and non-refractory total PM1, respectively.

  13. Estimating marine aerosol particle volume and number from Maritime Aerosol Network data

    Directory of Open Access Journals (Sweden)

    A. M. Sayer

    2012-09-01

    Full Text Available As well as spectral aerosol optical depth (AOD, aerosol composition and concentration (number, volume, or mass are of interest for a variety of applications. However, remote sensing of these quantities is more difficult than for AOD, as it is more sensitive to assumptions relating to aerosol composition. This study uses spectral AOD measured on Maritime Aerosol Network (MAN cruises, with the additional constraint of a microphysical model for unpolluted maritime aerosol based on analysis of Aerosol Robotic Network (AERONET inversions, to estimate these quantities over open ocean. When the MAN data are subset to those likely to be comprised of maritime aerosol, number and volume concentrations obtained are physically reasonable. Attempts to estimate surface concentration from columnar abundance, however, are shown to be limited by uncertainties in vertical distribution. Columnar AOD at 550 nm and aerosol number for unpolluted maritime cases are also compared with Moderate Resolution Imaging Spectroradiometer (MODIS data, for both the present Collection 5.1 and forthcoming Collection 6. MODIS provides a best-fitting retrieval solution, as well as the average for several different solutions, with different aerosol microphysical models. The "average solution" MODIS dataset agrees more closely with MAN than the "best solution" dataset. Terra tends to retrieve lower aerosol number than MAN, and Aqua higher, linked with differences in the aerosol models commonly chosen. Collection 6 AOD is likely to agree more closely with MAN over open ocean than Collection 5.1. In situations where spectral AOD is measured accurately, and aerosol microphysical properties are reasonably well-constrained, estimates of aerosol number and volume using MAN or similar data would provide for a greater variety of potential comparisons with aerosol properties derived from satellite or chemistry transport model data. However, without accurate AOD data and prior knowledge of

  14. Global Aerosol Optical Models and Lookup Tables for the New MODIS Aerosol Retrieval over Land

    Science.gov (United States)

    Levy, Robert C.; Remer, Loraine A.; Dubovik, Oleg

    2007-01-01

    Since 2000, MODIS has been deriving aerosol properties over land from MODIS observed spectral reflectance, by matching the observed reflectance with that simulated for selected aerosol optical models, aerosol loadings, wavelengths and geometrical conditions (that are contained in a lookup table or 'LUT'). Validation exercises have showed that MODIS tends to under-predict aerosol optical depth (tau) in cases of large tau (tau greater than 1.0), signaling errors in the assumed aerosol optical properties. Using the climatology of almucantur retrievals from the hundreds of global AERONET sunphotometer sites, we found that three spherical-derived models (describing fine-sized dominated aerosol), and one spheroid-derived model (describing coarse-sized dominated aerosol, presumably dust) generally described the range of observed global aerosol properties. The fine dominated models were separated mainly by their single scattering albedo (omega(sub 0)), ranging from non-absorbing aerosol (omega(sub 0) approx. 0.95) in developed urban/industrial regions, to neutrally absorbing aerosol (omega(sub 0) approx.90) in forest fire burning and developing industrial regions, to absorbing aerosol (omega(sub 0) approx. 0.85) in regions of savanna/grassland burning. We determined the dominant model type in each region and season, to create a 1 deg. x 1 deg. grid of assumed aerosol type. We used vector radiative transfer code to create a new LUT, simulating the four aerosol models, in four MODIS channels. Independent AERONET observations of spectral tau agree with the new models, indicating that the new models are suitable for use by the MODIS aerosol retrieval.

  15. Bacterial mitosis: partitioning protein ParA oscillates in spiral-shaped structures and positions plasmids at mid-cell

    DEFF Research Database (Denmark)

    Ebersbach, Gitte; Gerdes, Kenn; Charbon, Gitte Ebersbach

    2004-01-01

    with a single plasmid focus, the focus located preferentially at mid-cell. In cells with two foci, these located at quarter-cell positions. In the absence of ParB and parC1/parC2, ParA-GFP formed stationary helices extending from one end of the nucleoid to the other. In the presence of ParB and parC1/parC2, ParA-GFP......The par2 locus of Escherichia coli plasmid pB171 encodes oscillating ATPase ParA, DNA binding protein ParB and two cis-acting DNA regions to which ParB binds (parC1 and parC2). Three independent techniques were used to investigate the subcellular localization of plasmids carrying par2. In cells...... oscillated in spiral-shaped structures. Amino acid substitutions in ParA simultaneously abolished ParA spiral formation, oscillation and either plasmid localization or plasmid separation at mid-cell. Therefore, our results suggest that ParA spirals position plasmids at the middle of the bacterial nucleoid...

  16. AEROSOL PARTICLE COLLECTOR DESIGN STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S; Richard Dimenna, R

    2007-09-27

    A computational evaluation of a particle collector design was performed to evaluate the behavior of aerosol particles in a fast flowing gas stream. The objective of the work was to improve the collection efficiency of the device while maintaining a minimum specified air throughput, nominal collector size, and minimal power requirements. The impact of a range of parameters was considered subject to constraints on gas flow rate, overall collector dimensions, and power limitations. Potential improvements were identified, some of which have already been implemented. Other more complex changes were identified and are described here for further consideration. In addition, fruitful areas for further study are proposed.

  17. AN OVERVIEW ON: PHARMACEUTICAL AEROSOLS

    Directory of Open Access Journals (Sweden)

    Lahkar Sunita

    2012-09-01

    Full Text Available Pulmonary drug delivery system is found to have a wide range of application in the treatment of illness as well as in the research field due to its beneficial effect over the other dosage form. It is used not only in treatment of illness of asthma and chronic obstructive pulmonary disease (COPD but also finds its application in the treatment of diseases like diabetes, angina pectoris. This review article deals with an overview of one of the pulmonary drug delivery system called pharmaceutical aerosols.

  18. Influence of aerosol vertical distribution on radiative budget and climate

    Science.gov (United States)

    Nabat, Pierre; Michou, Martine; Saint-Martin, David; Watson, Laura

    2016-04-01

    Aerosols interact with shortwave and longwave radiation with ensuing consequences on radiative budget and climate. Aerosols are represented in climate models either using an interactive aerosol scheme including prognostic aerosol variables, or using climatologies, such as monthly aerosol optical depth (AOD) fields. In the first case, aerosol vertical distribution can vary rapidly, at a daily or even hourly scale, following the aerosol evolution calculated by the interactive scheme. On the contrary, in the second case, a fixed aerosol vertical distribution is generally imposed by climatological profiles. The objective of this work is to study the impact of aerosol vertical distribution on aerosol radiative forcing, with ensuing effects on climate. Simulations have thus been carried out using CNRM-CM, which is a global climate model including an interactive aerosol scheme representing the five main aerosol species (desert dust, sea-salt, sulfate, black carbon and organic matter). Several multi-annual simulations covering the past recent years are compared, including either the prognostic aerosol variables, or monthly AOD fields with different aerosol vertical distributions. In the second case, AOD fields directly come from the first simulation, so that all simulations have the same integrated aerosol loads. The results show that modifying the aerosol vertical distribution has a significant impact on radiative budget, with consequences on global climate. These differences, highlighting the importance of aerosol vertical distribution in climate models, probably come from the modification of atmospheric circulation induced by changes in the heights of the different aerosols. Besides, nonlinear effects in the superposition of aerosol and clouds reinforce the impact of aerosol vertical distribution, since aerosol radiative forcing depends highly upon the presence of clouds, and upon the relative vertical position of aerosols and clouds.

  19. Aerosol growth in the cover gas space

    International Nuclear Information System (INIS)

    An aerosol equation appropriate to the cover gas space is derived with a growth term specified by the total mass fluxes across the cavity. A relation between the maximum supersaturation reached in boundary layers and the aerosol number density and mean droplet size enables calculations to be made of the aerosol size distribution, the settling flux and mean aerosol density. Possible saturations are related to temperatures and sizes of nuclei which could induce heterogeneous nucleation, and it is concluded that nucleation is more likely to occur in the colder upper boundary layer. For a fixed saturation in this layer, the settling rate increases faster than the aerosol density with increase in pool temperature. (author)

  20. A statistical–numerical aerosol parameterization scheme

    Directory of Open Access Journals (Sweden)

    J.-P. Chen

    2013-10-01

    Full Text Available A new modal aerosol parameterization scheme, the statistical–numerical aerosol parameterization (SNAP, was developed for studying aerosol processes and aerosol–cloud interactions in regional or global models. SNAP applies statistical fitting on numerical results to generate accurate parameterization formulas without sacrificing details of the growth kernel. Processes considered in SNAP include fundamental aerosol processes as well as processes related to aerosol–cloud interactions. Comparison of SNAP with numerical solutions, analytical solutions, and binned aerosol model simulations showed that the new method performs well, with accuracy higher than that of the high-order numerical quadrature technique, and with much less computation time. The SNAP scheme has been implemented in regional air quality models, producing results very close to those using binned-size schemes or numerical quadrature schemes.

  1. Future options for aerosol delivery to children

    DEFF Research Database (Denmark)

    Bisgaard, H

    1999-01-01

    There is an increasing awareness of the importance of reliable aerosol delivery, with emphasis on the dose delivered to the lungs, optimal clinical control, cost-effectiveness, and safety in children. Dose prescription should relate to the expected lung dose rather than the factory-dispensed dose...... a proportional reduction in lung dose; hence, attention should be paid to reducing such dead space. Plastics in spacers cause a rapid loss of drug due to electrostatic attraction of the aerosol. The residence time of the aerosol, i.e., the time available for inhalation, is increased in nonelectrostatic spacers...... during inhalation and avoiding loss of aerosol during exhalation. An automatic device (AirPac) has been developed that transforms a dry-powder inhaler, Turbuhaler, into a spacer. In addition to the general advantages of spacer treatment, this device offers the advantage of a drug aerosol delivered...

  2. Beijing Olympics as an aerosol field experiment

    Science.gov (United States)

    Cermak, J.; Knutti, R.

    2009-05-01

    During the 2008 Olympic Summer Games, emission reductions were enforced in Beijing to improve air quality. Here we explore their effect on the regional aerosol load. We compare satellite-retrieved aerosol optical thickness (AOT) of that period with previous years, both in absolute terms and in a neural network approach taking into account the meteorological conditions. A statistically significant reduction of aerosol load is found in Beijing that decreases in magnitude and significance with increasing region size. Locally, the aerosol load (log(AOT)) was about 0.4 to 0.75 standard deviations below the levels expected for the prevailing meteorological situation. The small size of this effect relative to meteorological variability highlights the importance of regional aerosol transport.

  3. Multiple scattering in a dense aerosol atmosphere

    Directory of Open Access Journals (Sweden)

    S. Mukai

    2012-01-01

    Full Text Available This study was designed to develop an efficient algorithm to retrieve aerosol characteristics in aerosol events, which are associated with dense concentrations of aerosols in the atmosphere, such as a dust storm or a biomass burning plume. The idea of successive scattering of light is reviewed based on the theory of radiative transfer. Then derivation of the method of successive order of scattering (MSOS is interpreted in detail, and it is shown that MSOS is available for a simulation scheme in the dense radiation field being used to retrieve aerosol properties in the event with the high optical thickness. Finally our algorithms are practically applied for the biomass burning aerosol event over the Amazon using Aqua/MODIS data.

  4. Intercomparison test of various aerosol measurement techniques

    International Nuclear Information System (INIS)

    At the suggestion of the CONT group (Containment Loading and Response), which is a subgroup of the Safety Working Group of the Fast Reactor Coordinating Committee, a group of experts undertook a comparison of the techniques of sodium aerosol measurement used in various laboratories in the EC. The following laboratories took part in the exercise: CEN-Mol (Belgium), CEA-Cadarache (France), CEA-Fontenay-aux-Roses (France), KfK-Karlsruhe (Federal Republic of Germany), ENEA-Bologna (Italy), and UKAEA-Winfrith (United Kingdom). The objective of the aerosol measurement workshop was to assess the applicability and reliability of specific aerosol measuring instruments. Measurements performed with equipment from the participating laboratories were evaluated using a standard procedure. This enabled an estimate of the accuracy of the experimental data to be provided for the verification of aerosol codes. Thus these results can be used as input for the physical modelling of aerosol behaviour, and the work reported here is a contribution to the definition of the radioactive source term for severe accidents in LMFBRs. The aerosol experts participating in the exercise agreed to concentrate on the techniques of measuring aerosol particle size distributions. The tests were performed at the FAUNA test facility using the aerosol loop. A sodium spray fire, which provides a continuous aerosol source of variable concentration, was produced under open-loop conditions in this facility. Although the primary objective of the workshop was to determine the particle size distributions of the aerosols, measurements of the sodium mass concentration were also made

  5. Des guides touristiques pour le peuple et par le peuple

    Directory of Open Access Journals (Sweden)

    Ninon Vinsonneau

    2006-04-01

    Full Text Available Le Federal Writers’ Project (FWP constitua l’un des quatre programmes « culturels » lancés par l’administration du New Deal en 1935 en vue de résorber le problème du chômage parmi les professions dites « en col blanc ». Il employa de 1935 à 1943, entre quatre et six mille chômeurs par an, tous membres des « professions de l’écrit » — les « écrivains », au sens large que l’administration fédérale donnait à ce terme : romanciers, poètes, dramaturges, mais aussi journalistes, enseignants, cherc...

  6. La syphilis congenitale revelee par une fracture spontanee

    Directory of Open Access Journals (Sweden)

    Mounia Lakhdar Idrissi

    2011-11-01

    Full Text Available Alors qu�elle est actuellement oubliee dans les pays developpes, la syphilis congenitale se voit encore chez nous faute du depistage antenatal. Ses formes cliniques sont polymorphes et orientent a tord vers d�autres pathologies surtout en periode neonatale. Le diagnostic n�est donc pas toujours facile. La revelation d�une syphilis congenitale par une fracture spontanee est exceptionnellement decrite. Nous rapportons dans ce travail le cas d�un nourrisson de 2 mois ramene en consultation pour limitation douloureuse des mouvements du bras droit. Le diagnostic est evoque sur les donnees radiologiques et confirme par la serologie syphilitique. Le traitement a repose essentiellement sur l�administration de la penicilline G avec une bonne evolution clinique.

  7. Diffusion d'un champ electromagnetique par un batiment modelise

    OpenAIRE

    Bourrely, Claude

    2008-01-01

    Cette étude présente la diffusion d'un champ électromagnétique par un batiment de bureaux modélisé suivant un réseau bipériodique, en particulier, l'objectif est de calculer le champ réfléchi et transmis. Ce champ est produit par une antenne extérieure au batiment, on suppose qu'elle émet une onde plane. On travaille dans un domaine de longueur d'onde qui est inférieur à la plus petite dimension de la structure, ce qui correspond à l'épaisseur des murs. Les calculs sont effectués suivant la m...

  8. Valorisation de biogaz pour industrie chimie par voie catalytique

    OpenAIRE

    Taimoor, Aqeel Ahmad

    2010-01-01

    La production de l'hydrogène à partir de biomasse est actuellement à l'étude mais la méthode de valorisation du biogaz (mélange H2/CO2) par réactions catalytiques, autres que la simple combustion, n'a pas encore été retenue. Par conséquent, le principal objectif de ce travail est d'explorer les autres voies. L'effet du CO2 sur le système catalytique est mal connu et seulement un effet négatif sur la dissociation de l'hydrogène a été mentionné. L'hydrogénation du toluène sur un catalyseur Pt a...

  9. Biological aerosol warner and analyser

    Science.gov (United States)

    Schlemmer, Harry; Kürbitz, Gunther; Miethe, Peter; Spieweck, Michael

    2006-05-01

    The development of an integrated sensor device BiSAM (Biological Sampling and Analysing Module) is presented which is designed for rapid detection of aerosol or dust particles potentially loaded with biological warfare agents. All functional steps from aerosol collection via immuno analysis to display of results are fully automated. The core component of the sensor device is an ultra sensitive rapid analyser PBA (Portable Benchtop Analyser) based on a 3 dimensional immuno filtration column of large internal area, Poly HRP marker technology and kinetic optical detection. High sensitivity despite of the short measuring time, high chemical stability of the micro column and robustness against interferents make the PBA an ideal tool for fielded sensor devices. It is especially favourable to combine the PBA with a bio collector because virtually no sample preparation is necessary. Overall, the BiSAM device is capable to detect and identify living micro organisms (bacteria, spores, viruses) as well as toxins in a measuring cycle of typically half an hour duration. In each batch up to 12 different tests can be run in parallel together with positive and negative controls to keep the false alarm rate low.

  10. L'exraction par micro-ondes: un choix de qualité

    OpenAIRE

    Ramdani, M.; Ghazi, Z.; Fadel, O.; Mouni, L.; Wathelet, Jean-Paul

    2010-01-01

    Le but de ce travail est de comparer l’extraction faite par chauffage classique (CC) avec celle réalisée sous micro-ondes (MO). Deux modes d’extraction ont été réalisés : - L’hydro-distillation par chauffage classique (extraction par entraînement à la vapeur d’un solvant) et, - L’hydro-distillation activée par micro-ondes. Les MO permettent un gain de temps considérable. Par exemple, dans le cas du lavandula dentata : on note une cinétique 3 fois plus rapide, de plus le rendement ...

  11. Effect of an aerosol- reduction device on spreading infected aerosols during ultrasonic scaling

    Directory of Open Access Journals (Sweden)

    Ghalyani Isfahani P. Assistant Professor"

    2003-07-01

    Full Text Available Statement of Problem: Ultrasonic Scaling is one of the main sources of producing infected aerosols in dentistry. These aerosols are able to spread pathogens such as microorganisms associated with tuberculosis, conjunctivitis, influenza and other respiratory diseases, herpetic and other skin diseases, ADIS and hepatitis B."nPurpose: The aim of this study was to investigate the clinical effectiveness of an aerosol- reduction device attaching to ultrasonic scaler handpiece."nMaterials and Methods: In this experimental study 18 patients participated. Randomly, mandibular and maxillary quadrants of one side, in each subject, were scaled using an ultrasonic scaler with aerosol-reduction device for 5 minutes. After 30 minutes, another quadrant was scaled by ultrasonic scaler without aerosol- reduction device. In order to determine the effectiveness of aerosol- reduction device, blood agar plates attached to the surgical mask of the operator, 30 cm far from the patient's mouth, were incubated in 37°c for three days and the colonies were counted. Median, Interquartile eange and Wilcoxon test, at the 0.05 level of significance, were used to analyze the data."nResults: The median and interquartile range for the number of colony forming units (CFUS without aerosol- reduction device was 17.5 (8, 24, while the median for the number of CFUS when using aerosol-reduction device was 0 (0, 1, indicating significant statistical difference (PO.001 Conclusion: The aerosol- reduction device significantly reduces the amount of aerosols produced during ultrasonic scaling.

  12. MetaPar: Metagenomic Sequence Assembly via Iterative Reclassification

    OpenAIRE

    Kim, MinJi; Ligo, Jonathan G.; Emad, Amin; Farnoud, Farzad; Milenkovic, Olgica; Veeravalli, Venugopal V.

    2013-01-01

    We introduce a parallel algorithmic architecture for metagenomic sequence assembly, termed MetaPar, which allows for significant reductions in assembly time and consequently enables the processing of large genomic datasets on computers with low memory usage. The gist of the approach is to iteratively perform read (re)classification based on phylogenetic marker genes and assembler outputs generated from random subsets of metagenomic reads. Once a sufficiently accurate classification within gen...

  13. Design Studies and Commissioning Plans for PARS Experimental Program

    OpenAIRE

    Mete, O.; Hanahoe, K.; G. Xia; Dover, M.; Wigram, M.; Wright, J.; Zhang, J.; Smith, J.

    2015-01-01

    PARS (Plasma Acceleration Research Station) is an electron beam driven plasma wakefield acceleration test stand proposed for VELA/CLARA facility in Daresbury Laboratory. In order to optimise various operational configurations, 2D numerical studies were performed by using VSIM for a range of parameters such as bunch length, radius, plasma density and positioning of the bunches with respect to each other for the two-beam acceleration scheme. In this paper, some of these numerical studies and co...

  14. Design Studies and Commissioning Plans for PARS Experimental Program

    CERN Document Server

    Mete, O; Xia, G; Dover, M; Wigram, M; Wright, J; Zhang, J; Smith, J

    2015-01-01

    PARS (Plasma Acceleration Research Station) is an electron beam driven plasma wakefield acceleration test stand proposed for VELA/CLARA facility in Daresbury Laboratory. In order to optimise various operational configurations, 2D numerical studies were performed by using VSIM for a range of parameters such as bunch length, radius, plasma density and positioning of the bunches with respect to each other for the two-beam acceleration scheme. In this paper, some of these numerical studies and considered measurement methods are presented.

  15. Four cases of endophthalmitis after 25-gauge pars plana vitrectomy

    OpenAIRE

    Mutoh T; Kadoya K; Chikuda M

    2012-01-01

    Tetsuya Mutoh, Koji Kadoya, Makoto ChikudaDepartment of Ophthalmology, Dokkyo Medical University Koshigaya Hospital, Koshigaya, Saitama, JapanAbstract: We report our recent experience with four cases of endophthalmitis (one male, three females) after 25-gauge pars plana vitrectomy (PPV). One was a case of persistent cystoid macular edema caused by branch retinal vein occlusion, whereas the remaining three were cases of epiretinal membrane. Preoperative antibiotics before the first PPV procedu...

  16. «La Promenade par les aventures surprenants»

    OpenAIRE

    Duarte, Alexandre Freire

    2010-01-01

    É nossa intenção, neste estudo, focar a atenção heurística no par: Jean-Joseph Surin (1600-1665), e Michel de Certeau, um homem que, intermitentemente – revelando uma vida queimada pelo fascínio por Jean-Joseph Surin –, constituiu, nas nossas mãos atentamente vazias, num vasto arvoredo que nos remetia continuamente para uma sombria clareira luminosa que irradiava do meio daquele.

  17. Taare Zameen Par and dyslexic savants

    OpenAIRE

    Chakravarty Ambar

    2009-01-01

    The film Taare Zameen Par (Stars upon the Ground) portrays the tormented life at school and at home of a child with dyslexia and his eventual success after his artistic talents are discovered by his art teacher at the boarding school. The film hints at a curious neurocognitive phenomenon of creativity in the midst of language disability, as exemplified in the lives of people like Leonardo da Vinci and Albert Einstein, both of whom demonstrated extraordinary creativity even though they were ...

  18. The ParMol package for frequent subgraph mining

    OpenAIRE

    Meinl, Thorsten; Wörlein, Marc; Urzova, Olga; Fischer, Ingrid; Philippsen, Michael

    2006-01-01

    Mining for frequent subgraphs in a graph database has become a popular topic in the last years. Algorithms to solve this problem are used in chemoinformatics to find common molecular fragments in a database of molecules represented as two-dimensional graphs. However; the search process in arbitrary graph structures includes costly graph and subgraph isomorphism tests. In our ParMol package we have implemented four of the most popular frequent subgraph miners using a common infrastructure: MoF...

  19. Pars Plana Vitrectomy and Intravitreal Phacoemulsification for Dropped Nuclei

    OpenAIRE

    Khalil Ghasemi Falavarjani; Masih Hashemi; Ali Jalili Fazel; Mehdi Modarres; Hossein Nazari; Mohammad-Mehdi Parvaresh

    2012-01-01

    Purpose: To report the outcomes of pars plana vitrectomy (PPV) and intravitreal phacoemulsification in patients with dropped nuclei/nuclear fragments following complicated cataract surgery. Methods: In this retrospective case series, charts of patients who had undergone PPV and intravitreal phacoemulsification for removal of dislocated nuclei/lens fragments were reviewed. After standard PPV, a conventional phacoemulsification probe with an amputated sleeve was used for grasping and emulsi...

  20. Results of pars plana vitrectomy after complicated phacoemulsification surgery

    OpenAIRE

    Alexandre Grandinetti; Diogo Suenaga; Fernanda M. Oliveira; Krissis Saliba Uliana Cruz; Laurinda Meneguette; Luciane Bugman Moreira

    2015-01-01

    Purpose: To identify the causes and outcomes of pars plana vitrectomy (PPV) in patients undergoing phacoemulsification with intraoperative complication and to analyze whether the interval between phacoemulsification and PPV interferes with best-corrected final visual acuity. Methods: This descriptive and retrospective analytical study was conducted in Paraná Eye Hospital in 2013. Data were collected from medical records of 38 patients who underwent complicated phacoemulsification and also req...

  1. Quantitative assessment of surf-produced sea spray aerosol

    NARCIS (Netherlands)

    Neele, F.P.; De Leeuw, G.; Jansen, M.; Stive, M.J.F.

    1998-01-01

    The first results are presented from a quantitative model describing the aerosol production in the surf zone. A comparison is made with aerosol produced in the surf zone as measured during EOPACE experiments in La Jolla and Monterey. The surf aerosol production was derived from aerosol concentration

  2. Applications of aerosol model in the reactor containment

    Directory of Open Access Journals (Sweden)

    Mossad Slama

    2014-10-01

    For spatially homogeneous aerosol of uniform chemical composition, the aerosol dynamic equation is solved in closed volume to simulate the radionuclide particle transport in the containment. The effects of initial conditions on the aerosol distribution, boundary layer thickness and the aerosol behaviour under source reinforcement (external source are considered.

  3. Gas/Aerosol partitioning: a simplified method for global modeling

    NARCIS (Netherlands)

    Metzger, S.M.

    2001-01-01

    The main focus of this thesis is the development of a simplified method to routinely calculate gas/aerosol partitioning of multicomponent aerosols and aerosol associated water within global atmospheric chemistry and climate models. Atmospheric aerosols are usually multicomponent mixtures, partl

  4. Protease activated receptors (PARS) mediation in gyroxin biological activity

    International Nuclear Information System (INIS)

    Gyroxin is a serine protease enzyme from the South American rattlesnake (Crotalus durissus terrificus) venom; it is only partially characterized and has multiple activities. Gyroxin induces blood coagulation, blood pressure decrease and a neurotoxic behavior named barrel rotation. The mechanisms involved in this neurotoxic activity are not known. Whereas gyroxin is a member of enzymes with high potential to become a new drug with clinical applications such as thrombin, batroxobin, ancrod, tripsyn and kalicrein, it is important to find out how gyroxin works. The analysis on agarose gel electrophoresis and circular dichroism confirmed the molecules' integrity and purity. The gyroxin intravenous administration in mice proved its neurotoxicity (barrel rotation). In vivo studies employing intravital microscopy proved that gyroxin induces vasodilation with the participation of protease activated receptors (PARs), nitric oxide and Na+K+ATPase. The leukocytes' adherence and rolling counting indicated that gyroxin has no pro inflammatory activity. Gyroxin induced platelet aggregation, which was blocked by inhibitors of PAR1 and PAR4 receptors (SCH 79797 and tcY-NH2, respectively). Finally, it was proved that the gyroxin temporarily alter the permeability of the blood brain barrier (BBB). Our study has shown that both the protease-activated receptors and nitric oxide are mediators involved in the biological activities of gyroxin. (author)

  5. Diagnostic Ultrasound and Pars Plana Vitrectomy in Endophthalmitis

    Institute of Scientific and Technical Information of China (English)

    Jingjing Huang; Zhenfang Wang; Lijuan Zou; Xiaofeng Lin; Yiwen Luo; Zhaohui Yuan

    2004-01-01

    Purpose: To compare the results by B-scan ultrasonography and findings in pars plana vitrectomy, and assess the diagnostic value of B-scan ultrasonography in endophthalmitis.Methods: Thirty eyes of 30 subjects diagnosed as endophthalmitis were selected, who undergone preoperative B-scan ultrasonography. The result of pars plana vitrectomy was recorded. The above two results were compared.Results: On the evaluation of vitreous and retinal states in the patients with endophthalmitis, the sensitivity of ultrasound was 90%~100%, and the specificity was 79%~100%.Poorer preoperative visual acuity was related with retinal detachment and retinal dissolution. The preoperative visual acuity in eyes with local vitreous opacity was better than with diffuse vitreous opacity.Conclusion: Comparison of the results of B-scan ultrasonography and the findings in pars plana vitrectomy showed B-scan ultrasonography is highly sensitive, specific, and is very helpful in the evaluation of endophthalmitis. B-scan ultrasonography can not only supply much information in the diagnosis of endophthalmitis but also inspect its trends and changes, which is helpful in the selection of treatment and planning the time of surgery.

  6. An automated baseline correction protocol for infrared spectra of atmospheric aerosols collected on polytetrafluoroethylene (Teflon) filters

    Science.gov (United States)

    Kuzmiakova, Adele; Dillner, Ann M.; Takahama, Satoshi

    2016-06-01

    , and (3) thermal optical reflectance (TOR) organic carbon (OC) and elemental carbon (EC) predictions. The discrepancy rate for a four-cluster solution is 10 %. For all functional groups but carboxylic COH the discrepancy is ≤ 10 %. Performance metrics obtained from TOR OC and EC predictions (R2 ≥ 0.94 %, bias ≤ 0.01 µg m-3, and error ≤ 0.04 µg m-3) are on a par with those obtained from uncorrected and PB-corrected spectra. The proposed protocol leads to visually and analytically similar estimates as those generated by the polynomial method. More importantly, the automated solution allows us and future users to evaluate its analytical reproducibility while minimizing reducible user bias. We anticipate the protocol will enable FT-IR researchers and data analysts to quickly and reliably analyze a large amount of data and connect them to a variety of available statistical learning methods to be applied to analyte absorbances isolated in atmospheric aerosol samples.

  7. ParB Partition Proteins: Complex Formation and Spreading at Bacterial and Plasmid Centromeres.

    Science.gov (United States)

    Funnell, Barbara E

    2016-01-01

    In bacteria, active partition systems contribute to the faithful segregation of both chromosomes and low-copy-number plasmids. Each system depends on a site-specific DNA binding protein to recognize and assemble a partition complex at a centromere-like site, commonly called parS. Many plasmid, and all chromosomal centromere-binding proteins are dimeric helix-turn-helix DNA binding proteins, which are commonly named ParB. Although the overall sequence conservation among ParBs is not high, the proteins share similar domain and functional organization, and they assemble into similar higher-order complexes. In vivo, ParBs "spread," that is, DNA binding extends away from the parS site into the surrounding non-specific DNA, a feature that reflects higher-order complex assembly. ParBs bridge and pair DNA at parS and non-specific DNA sites. ParB dimers interact with each other via flexible conformations of an N-terminal region. This review will focus on the properties of the HTH centromere-binding protein, in light of recent experimental evidence and models that are adding to our understanding of how these proteins assemble into large and dynamic partition complexes at and around their specific DNA sites. PMID:27622187

  8. A Bipolar Spindle of Antiparallel ParM Filaments Drives Bacterial Plasmid Segregation

    DEFF Research Database (Denmark)

    Gayathri, P; Fujii, T; Møller-Jensen, Jakob;

    2012-01-01

    To ensure their stable inheritance by daughter cells during cell division, bacterial low copy-number plasmids make simple DNA segregating machines that use an elongating protein filament between sister plasmids. In the ParMRC system of Escherichia coli R1 plasmid, ParM, an actin-like protein, forms...... the spindle between ParRC complexes on sister plasmids. Using a combination of structural work and total internal reflection fluorescence microscopy, we show that ParRC bound and could accelerate growth at only one end of polar ParM filaments, mechanistically resembling eukaryotic formins. The architecture...... of ParM filaments enabled two ParRC-bound filaments to associate in an antiparallel orientation, forming a bipolar spindle. The spindle elongated as a bundle of at least two antiparallel filaments, thereby pushing two plasmid clusters toward the poles....

  9. How thermodynamic environments control stratocumulus microphysics and interactions with aerosols

    International Nuclear Information System (INIS)

    Aerosol–cloud interactions are central to climate system changes and depend on meteorological conditions. This study identifies distinct thermodynamic regimes and proposes a conceptual framework for interpreting aerosol effects. In the analysis, ten years (2003–2012) of daily satellite-derived aerosol and cloud products are combined with reanalysis data to identify factors controlling Southeast Atlantic stratocumulus microphysics. Considering the seasonal influence of aerosol input from biomass burning, thermodynamic environments that feature contrasting microphysical cloud properties and aerosol–cloud relations are classified. While aerosol impact is stronger in unstable environments, it is mostly confined to situations with low aerosol loading (aerosol index AI ≲ 0.15), implying a saturation of aerosol effects. Situations with high aerosol loading are associated with weaker, seasonally contrasting aerosol-droplet size relationships, likely caused by thermodynamically induced processes and aerosol swelling. (letter)

  10. Aerosol Chemistry of Furfural and Sugars

    Science.gov (United States)

    Srithawirat, T.; Brimblecombe, P.

    2008-12-01

    Furfural and sugars (as levoglucosan equivalent) are derived from biomass burning and contribute to aerosol composition. This study examined the potential of furfural and levoglucosan to be tracers of biomass burning. Furfural is likely to be oxidized quickly so comparison with levoglucosan may give a sense of the age of the aerosols in forest fire smoke. However, few furfural emissions are available for biomass combustion. Furfural and sugars were determined in coarse aerosols (>2.4μm aerodynamic diameter) and fine aerosols (Furfural and sugars dominated in fine fractions, especially in the UK autumn. Sugars were found at 5.96-18.37 nmol m-3 in fine mode and 1.36-5.75 nmol m-3 in coarse mode aerosols in the UK. Furfural was found at 0.18-0.91 nmol m-3 and 0.05-0.51 nmol m-3 respectively in the same aerosols. Sugars were a dominant contributor to aerosol derived from biomass burning. Sugars and furfural were about 10 and 20 times higher during haze episodes in Malaysia. Laboratory experimental simulation suggested furfural is more rapid destroyed by UV and sunlight than levoglucosan.

  11. Aerosol Angstrom Absorption Coefficient Comparisons during MILAGRO.

    Science.gov (United States)

    Marley, N. A.; Marchany-Rivera, A.; Kelley, K. L.; Mangu, A.; Gaffney, J. S.

    2007-12-01

    Measurements of aerosol absorption were obtained as part of the MAX-Mex component of the MILAGRO field campaign at site T0 (Instituto Mexicano de Petroleo in Mexico City) by using a 7-channel aethalometer (Thermo- Anderson) during the month of March, 2006. The absorption measurements obtained in the field at 370, 470, 520, 590, 660, 880, and 950 nm were used to determine the aerosol Angstrom absorption exponents by linear regression. Since, unlike other absorbing aerosol species (e.g. humic like substances, nitrated PAHs), black carbon absorption is relatively constant from the ultraviolet to the infrared with an Angstrom absorption exponent of -1 (1), a comparison of the Angstrom exponents can indicate the presence of aerosol components with an enhanced UV absorption over that expected from BC content alone. The Angstrom exponents determined from the aerosol absorption measurements obtained in the field varied from - 0.7 to - 1.3 during the study and was generally lower in the afternoon than the morning hours, indicating an increase in secondary aerosol formation and photochemically generated UV absorbing species in the afternoon. Twelve-hour integrated samples of fine atmospheric aerosols (Petroleo (IMP) and CENICA.

  12. Aerosol Angstrom Absorption Coefficient Comparisons during MILAGRO.

    Science.gov (United States)

    Marley, N. A.; Marchany-Rivera, A.; Kelley, K. L.; Mangu, A.; Gaffney, J. S.

    2007-12-01

    Measurements of aerosol absorption were obtained as part of the MAX-Mex component of the MILAGRO field campaign at site T0 (Instituto Mexicano de Petroleo in Mexico City) by using a 7-channel aethalometer (Thermo- Anderson) during the month of March, 2006. The absorption measurements obtained in the field at 370, 470, 520, 590, 660, 880, and 950 nm were used to determine the aerosol Angstrom absorption exponents by linear regression. Since, unlike other absorbing aerosol species (e.g. humic like substances, nitrated PAHs), black carbon absorption is relatively constant from the ultraviolet to the infrared with an Angstrom absorption exponent of -1 (1), a comparison of the Angstrom exponents can indicate the presence of aerosol components with an enhanced UV absorption over that expected from BC content alone. The Angstrom exponents determined from the aerosol absorption measurements obtained in the field varied from - 0.7 to - 1.3 during the study and was generally lower in the afternoon than the morning hours, indicating an increase in secondary aerosol formation and photochemically generated UV absorbing species in the afternoon. Twelve-hour integrated samples of fine atmospheric aerosols (MILAGRO. This research was supported by the Office of Science (BER), U.S. Department of Energy Grant No. DE-FG02-07ER64329. We also wish to thank Mexican Scientists and students for their assistance from the Instituto Mexicano de Petroleo (IMP) and CENICA.

  13. Phase transformation and growth of hygroscopic aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Tang, I.N.

    1995-09-01

    Ambient aerosols frequently contain large portions of hygroscopic inorganic salts such as chlorides, nitrates, and sulfates in either pure or mixed forms. Such inorganic salt aerosols exhibit the properties of deliquescence and efflorescence in air. The phase transformation from a solid particle to a saline droplet usually occurs spontaneously when the relative humidity of the atmosphere reaches a level specific to the chemical composition of the aerosol particle. Conversely, when the relative humidity decreases and becomes low enough, the saline droplet will evaporate and suddenly crystallize, expelling all its water content. The phase transformation and growth of aerosols play an important role in many atmospheric processes affecting air quality, visibility degradation, and climate changes. In this chapter, an exposition of the underlying thermodynamic principles is given, and recent advances in experimental methods utilizing single-particle levitation are discussed. In addition, pertinent and available thermodynamic data, which are needed for predicting the deliquescence properties of single and multi-component aerosols, are compiled. This chapter is useful to research scientists who are either interested in pursuing further studies of aerosol thermodynamics, or required to model the dynamic behavior of hygroscopic aerosols in a humid environment.

  14. Improvement of aerosol counterflow two-jets unit for continuous measurement of water soluble components of atmospheric aerosols

    Czech Academy of Sciences Publication Activity Database

    Mikuška, Pavel; Kořínková, Alena; Večeřa, Zbyněk

    Italian Aerosol Society, 2015. 2ACH_P033. [European Aerosol Conference EAC 2015. 06.09.2015-11.09.2015, Milano] R&D Projects: GA ČR(CZ) GA14-25558S Institutional support: RVO:68081715 Keywords : aerosol instrumentation * aerosol particles * chemical composition Subject RIV: CB - Analytical Chemistry, Separation

  15. Light Absorbing Aerosols in Mexico City

    Science.gov (United States)

    Marley, N. A.; Kelley, K. L.; Kilaparty, P. S.; Gaffney, J. S.

    2008-12-01

    The direct effects of aerosol radiative forcing has been identified by the IPCC as a major uncertainty in climate modeling. The DOE Megacity Aerosol Experiment-Mexico City (MAX-Mex), as part of the MILAGRO study in March of 2006, was undertaken to reduce these uncertainties by characterization of the optical, chemical, and physical properties of atmospheric aerosols emitted from this megacity environment. Aerosol samples collected during this study using quartz filters were characterized in the uv-visible-infrared by using surface spectroscopic techniques. These included the use of an integrating sphere approach combined with the use of Kubelka-Munk theory to obtain aerosol absorption spectra. In past work black carbon has been assumed to be the only major absorbing species in atmospheric aerosols with an broad band spectral profile that follows a simple inverse wavelength dependence. Recent work has also identified a number of other absorbing species that can also add to the overall aerosol absorption. These include primary organics from biomass and trash burning and secondary organic aerosols including nitrated PAHs and humic-like substances, or HULIS. By using surface diffuse reflection spectroscopy we have also obtained spectra in the infrared that indicate significant IR absorption in the atmospheric window-region. These data will be presented and compared to spectra of model compounds that allow for evaluation of the potential importance of these species in adding strength to the direct radiative forcing of atmospheric aerosols. This work was supported by the Office of Science (BER), U.S. Department of Energy, Grant No. DE-FG02-07ER64327 as part of the Atmospheric Science Program.

  16. Effects of seed aerosols on the growth of secondary organic aerosols from the photooxidation of toluene

    Institute of Scientific and Technical Information of China (English)

    HAO Li-qing; WANG Zhen-ya; HUANG Ming-qiang; FANG Li; ZHANG Wei-jun

    2007-01-01

    Hydroxyl radical (·OH)-initiated photooxidation reaction of toluene was carried out in a self-made smog chamber. Four individual seed aerosols such as ammonium sulfate, ammonium nitrate, sodium silicate and calcium chloride, were introduced into the chamber to assess their influence on the growth of secondary organic aerosols (SOA). It was found that the low concentration of seed aerosols might lead to high concentration of SOA particles. Seed aerosols would promote rates of SOA formation at the start of the reaction and inhibit its formation rate with prolonging the reaction time. In the case of cv. 9000 pt/cm3 seed aerosol load, the addition of sodium silicate induced a same effect on the SOA formation as ammonium nitrate. The influence of the four individual seed aerosols on the generation of SOA increased in the order of calcium chloride>sodium silicate and ammonium nitrate> ammonium sulfate.

  17. Papers of the 14. french congress on aerosols CFA 98

    International Nuclear Information System (INIS)

    This french congress on the aerosols took place in Paris the 8 and 9 december 1998. It was presented in four main themes: the aerosols in the environment; the bio-aerosols, filtering and purifying; the aerosols metrology; the aerosols physic and application. Seven papers have been analyzed in INIS data base for their specific interest in nuclear industry. Eight other ones are analyzed in ETDE data base. (A.L.B.)

  18. Applications of aerosol model in the reactor containment

    OpenAIRE

    Mossad Slama; Mohammad Omar Shaker; Ragaa Aly; Magdy Sirwah

    2014-01-01

    The study simulates of aerosol dynamics including coagulation, deposition and source reinforcement. Typical applications are for nuclear reactor aerosols, aerosol reaction chambers and the production of purified materials. The model determines the aerosol number and volume distributions for an arbitrary number of particle-size classes, called sections. The user specifies the initial aerosol size distribution and the source generation rate of each component in each section. For spatially ho...

  19. Secondary organic aerosols: Formation potential and ambient data

    DEFF Research Database (Denmark)

    Barthelmie, R.J.; Pryor, S.C.

    1997-01-01

    Organic aerosols comprise a significant fraction of the total atmospheric particle loading and are associated with radiative forcing and health impacts. Ambient organic aerosol concentrations contain both a primary and secondary component. Herein, fractional aerosol coefficients (FAC) are used in...... conjunction with measurements of volatile organic compounds (VOC) to predict the formation potential of secondary organic aerosols (SOA) in the Lower Fraser Valley (LEV) of British Columbia. The predicted concentrations of SOA show reasonable accord with ambient aerosol measurements and indicate considerable...

  20. Aerosol classification by airborne high spectral resolution lidar observations

    OpenAIRE

    S. Groß; Esselborn, M.; Weinzierl, B.; M. Wirth; Fix, A.; Petzold, A

    2012-01-01

    During four aircraft field experiments with the DLR research aircraft Falcon in 1998 (LACE), 2006 (SAMUM-1) and 2008 (SAMUM-2 and EUCAARI), airborne High Spectral Resolution Lidar (HSRL) and in situ measurements of aerosol microphysical and optical properties were performed. Altogether, the properties of six different aerosol types and aerosol mixtures – Saharan mineral dust, Saharan dust mixtures, Canadian biomass burning aerosol, African biomass burning aerosol, anthropogenic polluti...

  1. Whole-body nanoparticle aerosol inhalation exposures.

    Science.gov (United States)

    Yi, Jinghai; Chen, Bean T; Schwegler-Berry, Diane; Frazer, Dave; Castranova, Vince; McBride, Carroll; Knuckles, Travis L; Stapleton, Phoebe A; Minarchick, Valerie C; Nurkiewicz, Timothy R

    2013-01-01

    Inhalation is the most likely exposure route for individuals working with aerosolizable engineered nano-materials (ENM). To properly perform nanoparticle inhalation toxicology studies, the aerosols in a chamber housing the experimental animals must have: 1) a steady concentration maintained at a desired level for the entire exposure period; 2) a homogenous composition free of contaminants; and 3) a stable size distribution with a geometric mean diameter generation of aerosols containing nanoparticles is quite challenging because nanoparticles easily agglomerate. This is largely due to very strong inter-particle forces and the formation of large fractal structures in tens or hundreds of microns in size (6), which are difficult to be broken up. Several common aerosol generators, including nebulizers, fluidized beds, Venturi aspirators and the Wright dust feed, were tested; however, none were able to produce nanoparticle aerosols which satisfy all criteria (5). A whole-body nanoparticle aerosol inhalation exposure system was fabricated, validated and utilized for nano-TiO2 inhalation toxicology studies. Critical components: 1) novel nano-TiO2 aerosol generator; 2) 0.5 m(3) whole-body inhalation exposure chamber; and 3) monitor and control system. Nano-TiO2 aerosols generated from bulk dry nano-TiO2 powders (primary diameter of 21 nm, bulk density of 3.8 g/cm(3)) were delivered into the exposure chamber at a flow rate of 90 LPM (10.8 air changes/hr). Particle size distribution and mass concentration profiles were measured continuously with a scanning mobility particle sizer (SMPS), and an electric low pressure impactor (ELPI). The aerosol mass concentration (C) was verified gravimetrically (mg/m(3)). The mass (M) of the collected particles was determined as M = (Mpost-Mpre), where Mpre and Mpost are masses of the filter before and after sampling (mg). The mass concentration was calculated as C = M/(Q*t), where Q is sampling flowrate (m(3)/min), and t is the sampling

  2. Capstone Depleted Uranium Aerosols: Generation and Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Parkhurst, MaryAnn; Szrom, Fran; Guilmette, Ray; Holmes, Tom; Cheng, Yung-Sung; Kenoyer, Judson L.; Collins, John W.; Sanderson, T. Ellory; Fliszar, Richard W.; Gold, Kenneth; Beckman, John C.; Long, Julie

    2004-10-19

    In a study designed to provide an improved scientific basis for assessing possible health effects from inhaling depleted uranium (DU) aerosols, a series of DU penetrators was fired at an Abrams tank and a Bradley fighting vehicle. A robust sampling system was designed to collect aerosols in this difficult environment and continuously monitor the sampler flow rates. Aerosols collected were analyzed for uranium concentration and particle size distribution as a function of time. They were also analyzed for uranium oxide phases, particle morphology, and dissolution in vitro. The resulting data provide input useful in human health risk assessments.

  3. Aerosol transport in severe reactor accidents

    International Nuclear Information System (INIS)

    Computer codes with different aerosol models were used for calculation of fission product transport and the results are compared. Experimental results from LACE, DEMONA and Marviken-V are compared with the calculations. The theory of aerosol nucleation and its influence on the fission product transport is discussed. The behaviour of hygroscopic aerosols is studied. The pool scrubbing models in the codes SPARC and SUPRA are reviewed and some calculational results are reported. The present status of knowledge in this field is assessed on the background of an international review. (orig./HP)

  4. The behaviour of sodium fire aerosols

    International Nuclear Information System (INIS)

    The knowledge of the behaviour of aerosols released in nuclear accidents is of great importance for nuclear reactor safety and environmental protection. In sodium cooled fast breeder reactor accidents may occur by leaking pipes resulting in considerable spill of sodium. Major amounts of airborne sodium fire aerosols will be formed due to the evaporation and reaction of hot sodium with oxygen. For estimating the environmental impact of these aerosols it is necessary to know their chemical and physical behaviour in containments and in the free atmosphere

  5. Electrical aerosol spectrometer of Tartu University

    Science.gov (United States)

    Tammet, H.; Mirme, A.; Tamm, E.

    The electrical aerosol spectrometer (EAS) of the parallel measuring principle at Tartu University is an efficient instrument for rapid measurement of the unstable size spectrum of aerosol particles. The measuring range from 10 nm to 10 μm is achieved by simultaneously using a pair of differential mobility analyzers with two different particle chargers. The particle spectrum is calculated and measurement errors are estimated in real time by using a least-squares method. Experimental calibration ensures reliability of measurement. The instrument is well suited for continuous monitoring of atmospheric aerosol.

  6. Aerosol versus solution composition in occupational exposures.

    Science.gov (United States)

    Rondia, D; Closset, J

    1985-11-01

    Some industrial processes, such as the electrolysis of zinc solutions, anodic oxidation of aluminum, ore flotation, etc., result in the generation of gas microbubbles; the composition of their liquid envelope depends on, but is not identical to, the composition of the bulk of the liquid phase. An aerosol of respirable size, often toxic or irritant, results from the bursting of the bubbles at a certain height above the liquid. Some factors governing the discrepancy between the composition of the aerosol and that of the liquid have been studied for metal ions in oceanic aerosols. It is not known if these factors also apply to concentrated solutions and to anions. PMID:4081778

  7. Direct SW aerosol radiative forcing over Portugal

    Directory of Open Access Journals (Sweden)

    D. Santos

    2008-10-01

    Full Text Available In this work, the evaluation of the aerosol radiative forcing at the top of the atmosphere as well as at the surface over the south of Portugal is made, particularly in the regions of Évora (38°34' N, 7°54' W and of Cabo da Roca (38°46' N, 9°38' W, during years 2004 and 2005.

    The radiative transfer calculations, using the radiative transfer code Second Simulation of the Satellite Signal in the Solar Spectrum (6S, combine ground-based measurements, from Aerosol Robotic NETwork (AERONET, and satellite measurements, from MODerate Imaging Spectroradiometer (MODIS, to estimate the direct SW aerosol radiative forcing. The method developed to retrieve the surface spectral reflectance is also presented, based on ground-based measurements (AERONET of the aerosol optical properties combined with the satellite-measured radiances (MODIS.

    The instantaneous direct SW aerosol radiative forcing values obtained at the top of the atmosphere are, in the majority of the cases, negative, indicating a tendency for cooling the Earth at the top of the atmosphere. For Desert Dust aerosols, over the Évora land region, the average forcing efficiency is estimated to be −25 Wm−2/AOT0.55 whereas for the Cabo da Roca area, the average forcing efficiency is −46 Wm−2/AOT0.55. In the presence of Forest Fire aerosols, both from short and long distances, the average value of forcing efficiency at the top of the atmosphere over Cabo da Roca is found to be −28 Wm−2/AOT0.55 and, over Évora, −27 Wm−2/AOT0.55. For specific situations, discussed in this work, the average surface direct SW aerosol radiative forcing efficiency due to the Desert Dust aerosols, in Évora region, is −66 Wm−2/AOT0.55, whereas in Cabo da Roca region, the corresponding average value is −38 Wm−2/AOT0.55

  8. Direct SW aerosol radiative forcing over Portugal

    Directory of Open Access Journals (Sweden)

    D. Santos

    2008-05-01

    Full Text Available The estimation of radiative forcing due to desert dust and forest fires aerosols is a very important issue since these particles are very efficient at scattering and absorbing both short and longwave radiation. In this work, the evaluation of the aerosol radiative forcing at the top of the atmosphere over the south of Portugal is made, particularly in the regions of Évora and of Cabo da Roca.

    The radiative transfer calculations combine ground-based and satellite measurements, to estimate the top of the atmosphere direct SW aerosol radiative forcing. The method developed to retrieve the surface spectral reflectance is also presented, based on ground-based measurements of the aerosol optical properties combined with the satellite-measured radiances.

    The aerosol direct radiative effect is shown to be very sensitive to the underlying surface, since different surface spectral reflectance values may originate different forcing values. The results obtained also illustrate the importance of considering the actual aerosol properties, in this case measured by ground-based instrumentation, particularly the aerosol single scattering albedo, because different aerosol single scattering albedo values can flip the sign of the direct SW aerosol radiative forcing.

    The instantaneous direct SW aerosol radiative forcing values obtained at the top of the atmosphere are, in the majority of the cases, negative, indicating a tendency for cooling the Earth. For Desert Dust aerosols, over Évora land region, the average forcing efficiency is estimated to be −25 W/m2/AOT0.55 whereas for Cabo da Roca area, the average forcing efficiency is −46 W/m2/AOT0.55. In the presence of Forest Fire aerosols, over Cabo da Roca region, the average value of forcing efficiency is −28 W/m2/AOT0.55 and over Évora region an average value of −33 W/m2/AOT0.55 is found.

  9. Nitrate aerosols today and in 2030: a global simulation including aerosols and tropospheric ozone

    OpenAIRE

    S. E. Bauer; Koch, D.; Unger, N.; Metzger, S. M.; Shindell, D. T.; Streets, D.G.

    2007-01-01

    Nitrate aerosols are expected to become more important in the future atmosphere due to the expected increase in nitrate precursor emissions and the decline of ammonium-sulphate aerosols in wide regions of this planet. The GISS climate model is used in this study, including atmospheric gas- and aerosol phase chemistry to investigate current and future (2030, following the SRES A1B emission scenario) atmospheric compositions. A set of sensitivity experiments was carried out to...

  10. Nitrate aerosols today and in 2030: a global simulation including aerosols and tropospheric ozone

    OpenAIRE

    S. E. Bauer; Koch, D.; Unger, N.; Metzger, S. M.; Shindell, D. T.; Streets, D.G.

    2007-01-01

    Nitrate aerosols are expected to become more important in the future atmosphere due to the expected increase in nitrate precursor emissions and the decline of ammonium-sulphate aerosols in wide regions of this planet. The GISS climate model is used in this study, including atmospheric gas- and aerosol phase chemistry to investigate current and future (2030, following the SRES A1B emission scenario) atmospheric compositions. A set of sensitivity experiments was carried out to quantify the indi...

  11. Importance of global aerosol modeling including secondary organic aerosol formed from monoterpene

    OpenAIRE

    Goto, Daisuke; Takemura, Toshihiko; Nakajima, Teruyuki

    2008-01-01

    A global three-dimensional aerosol transport-radiation model, coupled to an atmospheric general circulation model (AGCM), has been extended to improve the model process for organic aerosols, particularly secondary organic aerosols (SOA), and to estimate SOA contributions to direct and indirect radiative effects. Because the SOA formation process is complicated and unknown, the results in different model simulations include large differences. In this work, we simulate SOA production assuming v...

  12. Do anthropogenic, continental or coastal aerosol sources impact on a marine aerosol signature at Mace Head?

    OpenAIRE

    C. O'Dowd; Ceburnis, D.; J. Ovadnevaite; A Vaishya; Rinaldi, M.; Facchini, M. C.

    2014-01-01

    Atmospheric aerosols have been sampled and characterised at the Mace Head north-east (NE) Atlantic atmospheric research station since 1958, with many interesting phenomena being discovered. However, with the range of new discoveries and scientific advances, there has been a range of concomitant criticisms challenging the representativeness of aerosol sampled at the station compared to that of aerosol over the pristine open-ocean. Two recurring criticisms relate to the lack o...

  13. Nitrate aerosols today and in 2030: importance relative to other aerosol species and tropospheric ozone

    Directory of Open Access Journals (Sweden)

    S. E. Bauer

    2007-04-01

    Full Text Available Ammonium-nitrate aerosols are expected to become more important in the future atmosphere due to the expected increase in nitrate precursor emissions and the decline of ammonium-sulphate aerosols in wide regions of this planet. The GISS climate model is used in this study, including atmospheric gas- and aerosol phase chemistry to investigate current and future (2030, following the SRES A1B emission scenario atmospheric compositions. A set of sensitivity experiments was carried out to quantify the individual impact of emission- and physical climate change on nitrate aerosol formation. We found that future nitrate aerosol loads depend most strongly on changes that may occur in the ammonia sources. Furthermore, microphysical processes that lead to aerosol mixing play a very important role in sulphate and nitrate aerosol formation. The role of nitrate aerosols as climate change driver is analyzed and set in perspective to other aerosol and ozone forcings under pre-industrial, present day and future conditions. In the near future, year 2030, ammonium nitrate radiative forcing is about –0.14 W/m2 and contributes roughly 10% of the net aerosol and ozone forcing. The present day nitrate and pre-industrial nitrate forcings are –0.11 and –0.05 W/m2, respectively. The steady increase of nitrate aerosols since industrialization increases its role as a non greenhouse gas forcing agent. However, this impact is still small compared to greenhouse gas forcings, therefore the main role nitrate will play in the future atmosphere is as an air pollutant, with annual mean near surface air concentrations rising above 3 μg/m3 in China and therefore reaching pollution levels, like sulphate aerosols, in the fine particle mode.

  14. Nitrate aerosols today and in 2030: a global simulation including aerosols and tropospheric ozone

    Directory of Open Access Journals (Sweden)

    S. E. Bauer

    2007-10-01

    Full Text Available Nitrate aerosols are expected to become more important in the future atmosphere due to the expected increase in nitrate precursor emissions and the decline of ammonium-sulphate aerosols in wide regions of this planet. The GISS climate model is used in this study, including atmospheric gas- and aerosol phase chemistry to investigate current and future (2030, following the SRES A1B emission scenario atmospheric compositions. A set of sensitivity experiments was carried out to quantify the individual impact of emission- and physical climate change on nitrate aerosol formation. We found that future nitrate aerosol loads depend most strongly on changes that may occur in the ammonia sources. Furthermore, microphysical processes that lead to aerosol mixing play a very important role in sulphate and nitrate aerosol formation. The role of nitrate aerosols as climate change driver is analyzed and set in perspective to other aerosol and ozone forcings under pre-industrial, present day and future conditions. In the near future, year 2030, ammonium nitrate radiative forcing is about −0.14 W/m² and contributes roughly 10% of the net aerosol and ozone forcing. The present day nitrate and pre-industrial nitrate forcings are −0.11 and −0.05 W/m², respectively. The steady increase of nitrate aerosols since industrialization increases its role as a non greenhouse gas forcing agent. However, this impact is still small compared to greenhouse gas forcings, therefore the main role nitrate will play in the future atmosphere is as an air pollutant, with annual mean near surface air concentrations, in the fine particle mode, rising above 3 μg/m³ in China and therefore reaching pollution levels, like sulphate aerosols.

  15. Natural Radionuclides and Isotopic Signatures for Determining Carbonaceous Aerosol Sources, Aerosol Lifetimes, and Washout Processes

    Energy Technology Data Exchange (ETDEWEB)

    Gaffney, Jeffrey [Univ. of Arkansas, Little Rock, AR (United States)

    2012-12-12

    This is the final technical report. The project description is as follows: to determine the role of aerosol radiative forcing on climate, the processes that control their atmospheric concentrations must be understood, and aerosol sources need to be determined for mitigation. Measurements of naturally occurring radionuclides and stable isotopic signatures allow the sources, removal and transport processes, as well as atmospheric lifetimes of fine carbonaceous aerosols, to be evaluated.

  16. Simultaneous aerosol measurements of unusual aerosol enhancement in troposphere over Syowa Station, Antarctica

    Directory of Open Access Journals (Sweden)

    K. Hara

    2013-10-01

    Full Text Available Unusual aerosol enhancement is often observed at Syowa Station, Antarctica during winter through spring. Simultaneous aerosol measurements near the surface and in the upper atmosphere were conducted twice using a ground-based optical particle counter, a balloon-borne optical particle counter, and micro-pulse LIDAR (MPL in August and September 2012. During 13–15 August, aerosol enhancement occurred immediately after a storm condition. A high backscatter ratio and aerosol concentrations were observed from the surface to ca. 2.5 km over Syowa Station. Clouds appeared occasionally at the top of aerosol-enhanced layer during the episode. Aerosol enhancement was terminated on 15 August by strong winds caused by a cyclone's approach. In the second case on 5–7 September, aerosol number concentrations in Dp > 0.3 μm near the surface reached > 104 L−1 at about 15:00 UT on 5 September in spite of calm wind conditions, whereas MPL measurement exhibited aerosols were enhanced at about 04:00 UT at 1000–1500 m above Syowa Station. The aerosol enhancement occurred near the surface–ca. 4 km. In both cases, air masses with high aerosol enhancement below 2.5–3 km were transported mostly from the boundary layer over the sea-ice area. In addition, air masses at 3–4 km in the second case came from the boundary layer over the open-sea area. This air mass history strongly suggests that dispersion of sea-salt particles from the sea-ice surface contributes considerably to the aerosol enhancement in the lower free troposphere (about 3 km and that the release of sea-salt particles from the ocean surface engenders high aerosol concentrations in the free troposphere (3–4 km.

  17. Do anthropogenic or coastal aerosol sources impact on a clean marine aerosol signature at Mace Head?

    OpenAIRE

    C. O'Dowd; D. Ceburnis; J. Ovadnevaite; Rinaldi, M.; Facchini, M. C.

    2013-01-01

    Atmospheric aerosols have been sampled and characterised at the Mace Head North East (N.E.) Atlantic atmospheric research station since 1958, with many interesting phenomena being discovered. However, with the range of new discoveries and scientific advances, there has been a range of concomitant criticisms challenging the representativeness of aerosol sampled at the station to that of aerosol over the open ocean. Two recurring criticisms relate to the lack of representativeness due to enhanc...

  18. Search for Links between Organic Aerosols Measured by Aerosol Mass Spectrometer and EC/OC Analyzer

    Czech Academy of Sciences Publication Activity Database

    Vodička, Petr; Kubelová, Lucie; Makeš, Otakar; Schwarz, Jaroslav

    Prague : Czech Aerosol Society, 2014 - (Kubelová, L.), s. 47-48 ISBN 978-80-86186-64-1. [Annual Conference of the Czech Aerosol Society /15./. Valtice (CZ), 30.10.2014-31.10.2014] R&D Projects: GA ČR GAP209/11/1342 Institutional support: RVO:67985858 Keywords : atmospheric aerosols * AMS * ECOC Subject RIV: CF - Physical ; Theoretical Chemistry http://cas.icpf.cas.cz/download/Sbornik_VKCAS_2014.pdf

  19. Characterization of urban aerosol in Cork City (Ireland using aerosol mass spectrometry

    Directory of Open Access Journals (Sweden)

    M. Dall'Osto

    2012-11-01

    Full Text Available Ambient wintertime background urban aerosol in Cork City, Ireland, was characterized using aerosol mass spectrometry. During the three-week measurement study in 2009, 93% of the 1 200 000 single particles characterized by an Aerosol Time-Of-Flight Mass Spectrometer (TSI ATOFMS were classified into five organic-rich particle types, internally-mixed to different proportions with Elemental Carbon (EC, sulphate and nitrate while the remaining 7% was predominantly inorganic in nature. Non-refractory PM1 aerosol was also characterized using a High Resolution Time-Of-Flight Aerodyne Aerosol Mass Spectrometer (HR-ToF-AMS and was also found to comprise organic matter as the most abundant species (62%, followed by nitrate (15%, sulphate (9% and ammonium (9%, and then chloride (5%.

    Positive matrix factorization (PMF was applied to the HR-ToF-AMS organic matrix and a five-factor solution was found to describe the variance in the data well. Specifically, "Hydrocarbon-like" Organic Aerosol (HOA comprised 19% of the mass, "Oxygenated low volatility" Organic Aerosols (LV-OOA comprised 19%, "Biomass wood Burning" Organic Aerosol (BBOA comprised 23%, non-wood solid-fuel combustion "Peat and Coal" Organic Aerosol (PCOA comprised 21%, and finally, a species type characterized by primary m/z peaks at 41 and 55, similar to previously-reported "Cooking" Organic Aerosol (COA but possessing different diurnal variations to what would be expected for cooking activities, contributed 18%. Despite wood, cool and peat being minor fuel types used for domestic space heating in urban areas, their relatively low combustion efficiencies result in a significant contribution to PM1 aerosol mass (44% and 28% of the total organic aerosols mass and non refractory PM1, respectively.

  20. Simulation of climate response to aerosol direct and indirect effects with aerosol transport‐radiation model

    OpenAIRE

    Takemura, Toshihiko; Nozawa, Toru; Emori, Seita; Nakajima, Takashi-Y.; Nakajima, Teruyuki

    2005-01-01

    With a global aerosol transport‐radiation model coupled to a general circulation model, changes in the meteorological parameters of clouds, precipitation, and temperature caused by the direct and indirect effects of aerosols are simulated, and its radiative forcing are calculated. A microphysical parameterization diagnosing the cloud droplet number concentration based on the Köhler theory is introduced into the model, which depends not only on the aerosol particle number concentration but als...

  1. Natural Radionuclides and Isotopic Signatures for Determining Carbonaceous Aerosol Sources, Aerosol Lifetimes, and Washout Processes

    International Nuclear Information System (INIS)

    This is the final technical report. The project description is as follows: to determine the role of aerosol radiative forcing on climate, the processes that control their atmospheric concentrations must be understood, and aerosol sources need to be determined for mitigation. Measurements of naturally occurring radionuclides and stable isotopic signatures allow the sources, removal and transport processes, as well as atmospheric lifetimes of fine carbonaceous aerosols, to be evaluated.

  2. A mechanism for ParB-dependent waves of ParA, a protein related to DNA segregation during cell division in prokaryotes

    DEFF Research Database (Denmark)

    Hunding, Axel; Gerdes, Kenn; Charbon, Gitte Ebersbach

    2003-01-01

    Prokaryotic plasmids encode partitioning (par) loci involved in segregation of DNA to daughter cells at cell division. A functional fusion protein consisting of Walker-type ParA ATPase and green fluorescent protein (Gfp) oscillates back and forth within nucleoid regions with a wave period of about...

  3. Validation of MODIS and GEOV1 fPAR Products in a Boreal Forest Site in Finland

    Directory of Open Access Journals (Sweden)

    Titta Majasalmi

    2015-01-01

    Full Text Available Remote sensing of the fraction of absorbed Photosynthetically Active Radiation (fPAR has become a timely option to monitor forest productivity. However, only a few studies have had ground reference fPAR datasets containing both forest canopy and understory fPAR from boreal forests for the validation of satellite products. The aim of this paper was to assess the performance of two currently available satellite-based fPAR products: MODIS fPAR (MOD15A2, C5 and GEOV1 fPAR (g2_BIOPAR_FAPAR, as well as an NDVI-fPAR relationship applied to the MODIS surface reflectance product and a Landsat 8 image, in a boreal forest site in Finland. Our study area covered 16 km2 and field data were collected from 307 forest plots. For all plots, we obtained both forest canopy fPAR and understory fPAR. The ground reference total fPAR agreed better with GEOV1 fPAR than with MODIS fPAR, which showed much more temporal variation during the peak-season than GEOV1 fPAR. At the chosen intercomparison date in peak growing season, MODIS NDVI based fPAR estimates were similar to GEOV1 fPAR, and produced on average 0.01 fPAR units smaller fPAR estimates than ground reference total fPAR. MODIS fPAR and Landsat 8 NDVI based fPAR estimates were similar to forest canopy fPAR.

  4. The Two-Column Aerosol Project: Phase I - Overview and Impact of Elevated Aerosol Layers on Aerosol Optical Depth

    Energy Technology Data Exchange (ETDEWEB)

    Berg, Larry K.; Fast, Jerome D.; Barnard, James C.; Burton, Sharon; Cairns, Brian; Chand, Duli; Comstock, Jennifer M.; Dunagan, Stephen; Ferrare, Richard A.; Flynn, Connor J.; Hair, John; Hostetler, Chris A.; Hubbe, John M.; Jefferson, Anne; Johnson, Roy; Kassianov, Evgueni I.; Kluzek, Celine D.; Kollias, Pavlos; Lamer, Katia; Lantz, K.; Mei, Fan; Miller, Mark A.; Michalsky, Joseph; Ortega, Ivan; Pekour, Mikhail S.; Rogers, Ray; Russell, P.; Redemann, Jens; Sedlacek, Art; Segal Rozenhaimer, Michal; Schmid, Beat; Shilling, John E.; Shinozuka, Yohei; Springston, Stephen R.; Tomlinson, Jason M.; Tyrrell, Megan; Wilson, Jacqueline; Volkamer, Rainer M.; Zelenyuk, Alla; Berkowitz, Carl M.

    2016-01-08

    The Two-Column Aerosol Project (TCAP), which was conducted from June 2012 through June 2013, was a unique field study that was designed to provide a comprehensive data set that can be used to investigate a number of important climate science questions, including those related to aerosol mixing state and aerosol radiative forcing. The study was designed to sample the atmosphere at a number of altitudes, from near the surface to as high as 8 km, within two atmospheric columns; one located near the coast of North America (over Cape Cod, MA) and a second over the Atlantic Ocean several hundred kilometers from the coast. TCAP included the yearlong deployment of the U.S. Department of Energy’s (DOE) Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF) that was located at the base of the Cape Cod column, as well as summer and winter aircraft intensive observation periods of the ARM Aerial Facility. One important finding from TCAP is the relatively common occurrence (on four of six nearly cloud-free flights) of elevated aerosol layers in both the Cape Cod and maritime columns that were detected using the nadir pointing second-generation NASA high-spectral resolution lidar (HSRL-2). These layers contributed up to 60% of the total aerosol optical depth (AOD) observed in the column. Many of these layers were also intercepted by the aircraft configured for in situ sampling, and the aerosol in the layers was found to have increased amounts of biomass burning aerosol and nitrate compared to the aerosol found near the surface.

  5. The Truth about Stratospheric Aerosols: Key Results from SPARC`s Assessment of Stratospheric Aerosol Properties

    Science.gov (United States)

    Thomason, L. W.; Peter, T.

    2005-12-01

    Given the critical role it plays in ozone chemistry, the Assessment of Stratospheric Aerosol Properties (ASAP) has been carried out by the WCRP project on Stratospheric Process and their Role in Climate (SPARC). The objective of this report was to present a systematic analysis of the state of knowledge of stratospheric aerosols including their precursors. It includes an examination of precursor concentrations and trends, measurements of stratospheric aerosol properties, trends in those properties, and modeling their formation, transport, and distribution in both background and volcanic conditions. The assessment found that the dominant nonvolcanic stratospheric aerosol precursor gases are OCS, SO2, and tropospheric aerosol. Therefore, though SO2, human-related activities play a significant role in the observed background stratospheric aerosol. There is general agreement between measured OCS and modeling of its transformation to sulfate aerosol, and observed aerosols. However, there is a significant dearth of SO2 measurements, and the role of tropospheric SO2 in the stratospheric aerosol budget - while significant - remains a matter of some guesswork. The assessment also found that there is basic agreement between the various data sets and models particularly during periods of elevated loading. However, at background levels significant differences were found that indicate that substantial questions remain regarding the nature of stratospheric aerosol during these periods particularly in the lower stratosphere. For instance, during periods of very low aerosol loading significant differences exist between systems for key parameters including aerosol surface area density and extinction. At the same time, comparisons of models and satellite observations of aerosol extinction found good agreement at visible wavelengths above 20-25 km altitude region but are less satisfactory for infrared wavelengths. While there are some model short-comings relative to observations in

  6. Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds

    Energy Technology Data Exchange (ETDEWEB)

    Richard A. Ferrare; David D. Turner

    2011-09-01

    Project goals: (1) Use the routine surface and airborne measurements at the ARM SGP site, and the routine surface measurements at the NSA site, to continue our evaluations of model aerosol simulations; (2) Determine the degree to which the Raman lidar measurements of water vapor and aerosol scattering and extinction can be used to remotely characterize the aerosol humidification factor; (3) Use the high temporal resolution CARL data to examine how aerosol properties vary near clouds; and (4) Use the high temporal resolution CARL and Atmospheric Emitted Radiance Interferometer (AERI) data to quantify entrainment in optically thin continental cumulus clouds.

  7. Ensembles of satellite aerosol retrievals based on three AATSR algorithms within aerosol_cci

    Science.gov (United States)

    Kosmale, Miriam; Popp, Thomas

    2016-04-01

    Ensemble techniques are widely used in the modelling community, combining different modelling results in order to reduce uncertainties. This approach could be also adapted to satellite measurements. Aerosol_cci is an ESA funded project, where most of the European aerosol retrieval groups work together. The different algorithms are homogenized as far as it makes sense, but remain essentially different. Datasets are compared with ground based measurements and between each other. Three AATSR algorithms (Swansea university aerosol retrieval, ADV aerosol retrieval by FMI and Oxford aerosol retrieval ORAC) provide within this project 17 year global aerosol records. Each of these algorithms provides also uncertainty information on pixel level. Within the presented work, an ensembles of the three AATSR algorithms is performed. The advantage over each single algorithm is the higher spatial coverage due to more measurement pixels per gridbox. A validation to ground based AERONET measurements shows still a good correlation of the ensemble, compared to the single algorithms. Annual mean maps show the global aerosol distribution, based on a combination of the three aerosol algorithms. In addition, pixel level uncertainties of each algorithm are used for weighting the contributions, in order to reduce the uncertainty of the ensemble. Results of different versions of the ensembles for aerosol optical depth will be presented and discussed. The results are validated against ground based AERONET measurements. A higher spatial coverage on daily basis allows better results in annual mean maps. The benefit of using pixel level uncertainties is analysed.

  8. Overview of ACE-Asia Spring 2001 Investigations on Aerosol Radiative Effects and Related Aerosol Properties

    Science.gov (United States)

    Russell, Philip B.; Valero, F. P. J.; Flatau, P. J.; Bergin, M.; Holben, B.; Nakajima, T.; Pilewskie, P.; Bergstrom, R.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    A primary, ACE-Asia objective was to quantify the interactions between aerosols and radiation in the Asia-Pacific region. Toward this end, radiometric and related aerosol measurements were made from ocean, land, air and space platforms. Models that predict aerosol fields guided the measurements and are helping integrate and interpret results. Companion overview's survey these measurement and modeling components. Here we illustrate how these components were combined to determine aerosol radiative. impacts and their relation to aerosol properties. Because clouds can obscure or change aerosol direct radiative effects, aircraft and ship sorties to measure these effects depended on predicting and finding cloud-free areas and times with interesting aerosols present. Pre-experiment satellite cloud climatologies, pre-flight aerosol and cloud forecasts, and in-flight guidance from satellite imagery all helped achieve this. Assessments of aerosol regional radiative impacts benefit from the spatiotemporal coverage of satellites, provided satellite-retrieved aerosol properties are accurate. Therefore, ACE-Asia included satellite retrieval tests, as part of many comparisons to judge the consistency (closure) among, diverse measurements. Early results include: (1) Solar spectrally resolved and broadband irradiances and optical depth measurements from the C-130 aircraft and at Kosan, Korea yielded aerosol radiative forcing efficiencies, permitting comparisons between efficiencies of ACE-Asia and INDOEX aerosols, and between dust and "pollution" aerosols. Detailed results will be presented in separate papers. (2) Based on measurements of wavelength dependent aerosol optical depth (AOD) and single scattering albedo the estimated 24-h a average aerosol radiative forcing efficiency at the surface for photosynthetically active radiation (400 - 700 nm) in Yulin, China is approx. 30 W sq m per AOD(500 nm). (3) The R/V Brown cruise from Honolulu to Sea of Japan sampled an aerosol optical

  9. Papers of the 14. french congress on aerosols CFA 98; Actes du 14. congres francais sur les aerosols CFA 98

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    This french congress on the aerosols took place in Paris the 8 and 9 december 1998. It was presented in four main themes: the aerosols in the environment; the bio-aerosols, filtering and purifying; the aerosols metrology; the aerosols physic and application. Seven papers have been analyzed in INIS data base for their specific interest in nuclear industry. Eight other ones are analyzed in ETDE data base. (A.L.B.)

  10. Evaluation of spatio-temporal variability of Hamburg Aerosol Climatology against aerosol datasets from MODIS and CALIOP

    OpenAIRE

    V. Pappas; N. Hatzianastassiou; C. Papadimas; Matsoukas, C.; Kinne, S.; Vardavas, I.

    2013-01-01

    The new global aerosol climatology named HAC (Hamburg Aerosol Climatology) is compared against MODIS (MODerate resolution Imaging Spectroradiometer, Collection 5, 2000–2007) and CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization, Level 2-Version 3, 2006–2011) retrievals. The HAC aerosol optical depth (AOD) values are larger than MODIS in heavy aerosol load conditions (over land) and lower over oceans. Agreement between HAC and MODIS is better over land and for low AOD. Hemispherica...

  11. Retrieving global aerosol sources from satellites using inverse modeling

    Directory of Open Access Journals (Sweden)

    O. Dubovik

    2008-01-01

    Full Text Available Understanding aerosol effects on global climate requires knowing the global distribution of tropospheric aerosols. By accounting for aerosol sources, transports, and removal processes, chemical transport models simulate the global aerosol distribution using archived meteorological fields. We develop an algorithm for retrieving global aerosol sources from satellite observations of aerosol distribution by inverting the GOCART aerosol transport model.

    The inversion is based on a generalized, multi-term least-squares-type fitting, allowing flexible selection and refinement of a priori algorithm constraints. For example, limitations can be placed on retrieved quantity partial derivatives, to constrain global aerosol emission space and time variability in the results. Similarities and differences between commonly used inverse modeling and remote sensing techniques are analyzed. To retain the high space and time resolution of long-period, global observational records, the algorithm is expressed using adjoint operators.

    Successful global aerosol emission retrievals at 2°×2.5 resolution were obtained by inverting GOCART aerosol transport model output, assuming constant emissions over the diurnal cycle, and neglecting aerosol compositional differences. In addition, fine and coarse mode aerosol emission sources were inverted separately from MODIS fine and coarse mode aerosol optical thickness data, respectively. These assumptions are justified, based on observational coverage and accuracy limitations, producing valuable aerosol source locations and emission strengths. From two weeks of daily MODIS observations during August 2000, the global placement of fine mode aerosol sources agreed with available independent knowledge, even though the inverse method did not use any a priori information about aerosol sources, and was initialized with a "zero aerosol emission" assumption. Retrieving coarse mode aerosol emissions was less successful

  12. Inertial classification of aerosols for size measurement

    International Nuclear Information System (INIS)

    Major inertial size classification techniques and devices have been reviewed. Principles of operation, advantages and limitations of each technique, precautions to be taken in design and operation of the devices are discussed with respect to their applications to nuclear aerosol analyses. Included in the review are sedimentation chambers, elutriators, cascade impactors, centrifuges and cyclones. Based on the comparison of various techniques, it has been concluded that spiral duct centrifuges and cascade impactors are suitable for measuring the aerosol size distribution for nuclear aerosol applications. It is also emphasized that because of the possible operational problems and the variations in performance resulting from sampling conditions, any inertial aerosol measurement device should be calibrated and evaluated under conditions as close as possible to the experimental conditions expected during their use

  13. Aerosol transport in severe reactor accidents

    International Nuclear Information System (INIS)

    Aerosol behaviour in the reactor containment was studied in the case of severe reactor accidents. The study was performed in a Nordic group during the years 1985 to 1988. Computer codes with different aerosol models were used for calculation of fission product transport and the results are compared. Experimental results from LACE, DEMONA and Marviken-V are compared with the calculations. The theory of aerosol nucleation and its influence on the fission product transport is discussed. The behaviour of hygroscopic aerosols is studied. The pool scrubbing models in the codes SPARC and SUPRA are reviewed and some knowledge in this field is assessed on the background of an international rewiew. (author) 60 refs

  14. Humidity Dependent Extinction of Clay Aerosols

    Science.gov (United States)

    Greenslade, M. E.; Attwood, A. R.

    2010-12-01

    Aerosols play an important role in the Earth’s radiative balance by directly scattering and absorbing radiation. The magnitude of aerosol forcing can be altered by changes in relative humidity which cause aerosol size, shape and refractive index to vary. To quantify these effects, a custom cavity ring down instrument operated at 532 nm with two sample channels measures aerosols extinction under dry conditions and at elevated humidity. The optical growth, fRH(ext), is determined as a ratio of the extinction cross section at high relative humidity to that under dry conditions. Three key clay components of mineral dust and mixtures of clay components with ammonium sulfate are investigated using this method. Experimentally obtained optical growth is compared with physical growth factors from the literature and our work determined using several different techniques. Further, Mie theory calculations based on published optical constants are compared with experimental results. Differences between theory and experiment will be discussed.

  15. Direct impact aerosol sampling by electrostatic precipitation

    Science.gov (United States)

    Braden, Jason D.; Harter, Andrew G.; Stinson, Brad J.; Sullivan, Nicholas M.

    2016-02-02

    The present disclosure provides apparatuses for collecting aerosol samples by ionizing an air sample at different degrees. An air flow is generated through a cavity in which at least one corona wire is disposed and electrically charged to form a corona therearound. At least one grounded sample collection plate is provided downstream of the at least one corona wire so that aerosol ions generated within the corona are deposited on the at least one grounded sample collection plate. A plurality of aerosol samples ionized to different degrees can be generated. The at least one corona wire may be perpendicular to the direction of the flow, or may be parallel to the direction of the flow. The apparatus can include a serial connection of a plurality of stages such that each stage is capable of generating at least one aerosol sample, and the air flow passes through the plurality of stages serially.

  16. AEROSOL BEHAVIOR IN CHROMIUM WASTE INCINERATION

    Institute of Scientific and Technical Information of China (English)

    Suyuan Yu

    2003-01-01

    Cr2O3 is considered as the dominant incineration product during the combustion disposal of chromium waste. A hydrogen/air diffusion flame was employed to simulate the industrial process of incineration. Cr2O3 aerosols were generated inside the flame by the gas phase reaction of chromium and oxygen. Chromium came from the rapid decomposition of chromium hexacarbonyl (Cr(CO)6) at room temperature and was carried into the combustion chamber by hydrogen. Aerosol and clusters can then be easily formed in the flame by nucleation and coagulation. A two dimensional Discrete-Sectional Model (DSM) was adopted to calculate the Cr2O3 aerosol behavior. The experimental measurement method was Dynamic Light Scattering. The numerically predicted results agreed well with those of the experimental measurement. Both results show that the Cr2O3 aerosol size reached about 70 nanometers at the flame top.

  17. Remote Sensing of Aerosol Properties during CARES

    Energy Technology Data Exchange (ETDEWEB)

    Kassianov, Evgueni I.; Barnard, James C.; Pekour, Mikhail S.; Flynn, Connor J.; Ferrare, R.; Hostetler, Chris A.; Hair, John; Jobson, Bertram Thomas

    2011-10-01

    One month of MFRSR data collected at two sites in the central California (USA) region during the CARES campaign are processed and the MFRSR-derived AODs at 500 nm wavelength are compared with available AODs provided by AERONET measurements. We find that the MFRSR and AERONET AODs are small ({approx}0.05) and comparable. A reasonable quantitative agreement between column aerosol size distributions (up to 2 um) from the MFRSR and AERONET retrievals is illustrated as well. Analysis of the retrieved (MFRSR and AERONET) and in situ measured aerosol size distributions suggests that the contribution of the coarse mode to aerosol optical properties is substantial for several days. The results of a radiative closure experiment performed for the two sites and one-month period show a favorable agreement between the calculated and measured broadband downwelling irradiances (bias does not exceed about 3 Wm-2), and thus imply that the MFRSR-derived aerosol optical properties are reasonable.

  18. Nanometer and ultrafine aerosols from radon radiolysis

    International Nuclear Information System (INIS)

    The ability of ionizing radiation to produce condensation nuclei aerosols in filtered air is well known. Recent studies have indicated that radiolysis results initially in the production of highly diffusive, nanometer-sized (5 nm) can then evolve by coagulation and growth processes. The nanometer nuclei are, however, poorly detected by condensation nuclei counters (CNCs) since CNC efficiencies drop sharply for particle sizesx molecular cluster aerosols from the decay of radon, and sulfuric acid nanometer nuclei and ultrafine aerosols from the radiolytic oxidation of SO2 in radon-air mixtures, were studied through wire screen-based size distribution measurements of the 218Po radioactivity associated with the aerosols. Comparisons with conventional diffusion battery-CNC derived number size distributions are also presented. (author)

  19. Aerosol Best Estimate Value-Added Product

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, C; Turner, D; Koontz, A; Chand, D; Sivaraman, C

    2012-07-19

    The objective of the Aerosol Best Estimate (AEROSOLBE) value-added product (VAP) is to provide vertical profiles of aerosol extinction, single scatter albedo, asymmetry parameter, and Angstroem exponents for the atmospheric column above the Central Facility at the ARM Southern Great Plains (SGP) site. We expect that AEROSOLBE will provide nearly continuous estimates of aerosol optical properties under a range of conditions (clear, broken clouds, overcast clouds, etc.). The primary requirement of this VAP was to provide an aerosol data set as continuous as possible in both time and height for the Broadband Heating Rate Profile (BBHRP) VAP in order to provide a structure for the comprehensive assessment of our ability to model atmospheric radiative transfer for all conditions. Even though BBHRP has been completed, AEROSOLBE results are very valuable for environmental, atmospheric, and climate research.

  20. Par-4-mediated recruitment of Amida to the actin cytoskeleton leads to the induction of apoptosis

    International Nuclear Information System (INIS)

    Par-4 (prostate apoptosis response-4) sensitizes cells to apoptotic stimuli, but the exact mechanisms are still poorly understood. Using Par-4 as bait in a yeast two-hybrid screen, we identified Amida as a novel interaction partner, a ubiquitously expressed protein which has been suggested to be involved in apoptotic processes. Complex formation of Par-4 and Amida occurs in vitro and in vivo and is mediated via the C-termini of both proteins, involving the leucine zipper of Par-4. Amida resides mainly in the nucleus but displays nucleo-cytoplasmic shuttling in heterokaryons. Upon coexpression with Par-4 in REF52.2 cells, Amida translocates to the cytoplasm and is recruited to actin filaments by Par-4, resulting in enhanced induction of apoptosis. The synergistic effect of Amida/Par-4 complexes on the induction of apoptosis is abrogated when either Amida/Par-4 complex formation or association of these complexes with the actin cytoskeleton is impaired, indicating that the Par-4-mediated relocation of Amida to the actin cytoskeleton is crucial for the pro-apoptotic function of Par-4/Amida complexes in REF52.2 cells. The latter results in enhanced phosphorylation of the regulatory light chain of myosin II (MLC) as has previously been shown for Par-4-mediated recruitment of DAP-like kinase (Dlk), suggesting that the recruitment of nuclear proteins involved in the regulation of apoptotic processes to the actin filament system by Par-4 represents a potent mechanism how Par-4 can trigger apoptosis

  1. Prague Aerosol Supersite, Suchdol (PASS, urban background)

    Czech Academy of Sciences Publication Activity Database

    Ždímal, Vladimír; Ondráček, Jakub; Zíková, Naděžda; Vodička, Petr; Makeš, Otakar; Řimnáčová, Daniela; Štefancová, Lucia; Šilhavý, J.; Smolík, Jiří; Schwarz, Jaroslav

    - : -, 2012, P286. [European Aerosol Confrernce EAC 2012. Granada (ES), 02.09.2012-07.09.2012] R&D Projects: GA ČR GAP209/11/1342 Grant ostatní: MF NF(CZ) A/CZ0046/2/2001; UFIREG(XE) 3CE288P3 Institutional support: RVO:67985858 Keywords : atmospheric aerosol * urban background Subject RIV: CF - Physical ; Theoretical Chemistry http://www.eac2012.com/EAC2012Book/3.html

  2. Photophoretic levitation of engineered aerosols for geoengineering

    OpenAIRE

    Keith, David W.

    2010-01-01

    Aerosols could be injected into the upper atmosphere to engineer the climate by scattering incident sunlight so as to produce a cooling tendency that may mitigate the risks posed by the accumulation of greenhouse gases. Analysis of climate engineering has focused on sulfate aerosols. Here I examine the possibility that engineered nanoparticles could exploit photophoretic forces, enabling more control over particle distribution and lifetime than is possible with sulfates, perhaps allowing clim...

  3. Aerosol fabrication methods for monodisperse nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xingmao; Brinker, C Jeffrey

    2014-10-21

    Exemplary embodiments provide materials and methods for forming monodisperse particles. In one embodiment, the monodisperse particles can be formed by first spraying a nanoparticle-containing dispersion into aerosol droplets and then heating the aerosol droplets in the presence of a shell precursor to form core-shell particles. By removing either the shell layer or the nanoparticle core of the core-shell particles, monodisperse nanoparticles can be formed.

  4. Improved Gridded Aerosol Data for India

    Energy Technology Data Exchange (ETDEWEB)

    Gueymard, C. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sengupta, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2013-11-01

    Using point data from ground sites in and around India equipped with multiwavelength sunphotometers, as well as gridded data from space measurements or from existing aerosol climatologies, an improved gridded database providing the monthly aerosol optical depth at 550 nm (AOD550) and Angstrom exponent (AE) over India is produced. Data from 83 sunphotometer sites are used here as ground truth tocalibrate, optimally combine, and validate monthly gridded data during the period from 2000 to 2012.

  5. Application of aerosol technology in LMFBR design

    International Nuclear Information System (INIS)

    Aerosol technology is applied in several areas in the safety assessment of liquid metal fast breeder reactors. This paper discusses the application of this technology in the assessment of the Clinch River Breeder Reactor Plant. The importance of considering aerosol effects is discussed for sodium fires, the assessment of site suitability and the assessment of the consequences of accidents beyond the design base such as hypothetical core disruptive accidents. Areas in which further development work could have the most impact are indicated

  6. Electrically Driven Technologies for Radioactive Aerosol Abatement

    Energy Technology Data Exchange (ETDEWEB)

    David W. DePaoli; Ofodike A. Ezekoye; Costas Tsouris; Valmor F. de Almeida

    2003-01-28

    The purpose of this research project was to develop an improved understanding of how electriexecy driven processes, including electrocoalescence, acoustic agglomeration, and electric filtration, may be employed to efficiently treat problems caused by the formation of aerosols during DOE waste treatment operations. The production of aerosols during treatment and retrieval operations in radioactive waste tanks and during thermal treatment operations such as calcination presents a significant problem of cost, worker exposure, potential for release, and increased waste volume.

  7. Development of a cavity enhanced aerosol albedometer

    OpenAIRE

    Zhao, W.; Xu, X.; Dong, M.; Chen, W.; X. Gu; Hu, C; Huang, Y.; Gao, X; Huang, W.; Zhang, W

    2014-01-01

    We report on the development of a cavity enhanced aerosol single scattering albedometer incorporating incoherent broad-band cavity-enhanced spectroscopy (IBBCEAS) approach and an integrating sphere (IS) for simultaneous in situ measurements of aerosol scattering and extinction coefficients in the exact same sample volume. The cavity enhanced albedometer employed a blue light-emitting diode (LED) based IBBCEAS approach for the measurement of wavelength-resolv...

  8. Aged organic aerosol in the Eastern Mediterranean: the Finokalia Aerosol Measurement Experiment – 2008

    Directory of Open Access Journals (Sweden)

    L. Hildebrandt

    2010-05-01

    Full Text Available Aged organic aerosol (OA was measured at a remote coastal site on the island of Crete, Greece during the Finokalia Aerosol Measurement Experiment-2008 (FAME-2008, which was part of the EUCAARI intensive campaign of May 2008. The site at Finokalia is influenced by air masses from different source regions, including long-range transport of pollution from continental Europe. A quadrupole aerosol mass spectrometer (Q-AMS was employed to measure the size-resolved chemical composition of non-refractory submicron aerosol (NR-PM1, and to estimate the extent of oxidation of the organic aerosol. Factor analysis was used to gain insights into the processes and sources affecting the OA composition. The particles were internally mixed and liquid. The largest fraction of the dry NR-PM1 sampled was ammonium sulfate and ammonium bisulfate, followed by organics and a small amount of nitrate. The variability in OA composition could be explained with two factors of oxygenated organic aerosol (OOA with differing extents of oxidation but similar volatility. Hydrocarbon-like organic aerosol (HOA was not detected. There was no statistically significant diurnal variation in the bulk composition of NR-PM1 such as total sulfate or total organic aerosol concentrations. However, the OA composition exhibited statistically significant diurnal variation with more oxidized OA in the afternoon. The organic aerosol was highly oxidized, regardless of the source region. Total OA concentrations also varied little with source region, suggesting that local sources had only a small effect on OA concentrations measured at Finokalia. The aerosol was transported for about one day before arriving at the site, corresponding to an OH exposure of approximately 4×1011 molecules cm−3 s. The constant extent of oxidation suggests that atmospheric aging results in a highly oxidized OA at these OH exposures, regardless of the aerosol source.

  9. Aged organic aerosol in the Eastern Mediterranean: the Finokalia Aerosol Measurement Experiment - 2008

    Science.gov (United States)

    Hildebrandt, L.; Engelhart, G. J.; Mohr, C.; Kostenidou, E.; Lanz, V. A.; Bougiatioti, A.; Decarlo, P. F.; Prevot, A. S. H.; Baltensperger, U.; Mihalopoulos, N.; Donahue, N. M.; Pandis, S. N.

    2010-05-01

    Aged organic aerosol (OA) was measured at a remote coastal site on the island of Crete, Greece during the Finokalia Aerosol Measurement Experiment-2008 (FAME-2008), which was part of the EUCAARI intensive campaign of May 2008. The site at Finokalia is influenced by air masses from different source regions, including long-range transport of pollution from continental Europe. A quadrupole aerosol mass spectrometer (Q-AMS) was employed to measure the size-resolved chemical composition of non-refractory submicron aerosol (NR-PM1), and to estimate the extent of oxidation of the organic aerosol. Factor analysis was used to gain insights into the processes and sources affecting the OA composition. The particles were internally mixed and liquid. The largest fraction of the dry NR-PM1 sampled was ammonium sulfate and ammonium bisulfate, followed by organics and a small amount of nitrate. The variability in OA composition could be explained with two factors of oxygenated organic aerosol (OOA) with differing extents of oxidation but similar volatility. Hydrocarbon-like organic aerosol (HOA) was not detected. There was no statistically significant diurnal variation in the bulk composition of NR-PM1 such as total sulfate or total organic aerosol concentrations. However, the OA composition exhibited statistically significant diurnal variation with more oxidized OA in the afternoon. The organic aerosol was highly oxidized, regardless of the source region. Total OA concentrations also varied little with source region, suggesting that local sources had only a small effect on OA concentrations measured at Finokalia. The aerosol was transported for about one day before arriving at the site, corresponding to an OH exposure of approximately 4×1011 molecules cm-3 s. The constant extent of oxidation suggests that atmospheric aging results in a highly oxidized OA at these OH exposures, regardless of the aerosol source.

  10. Operational aerosol and dust storm forecasting

    International Nuclear Information System (INIS)

    The U. S. Navy now conducts operational forecasting of aerosols and dust storms on global and regional scales. The Navy Aerosol Analysis and Prediction System (NAAPS) is run four times per day and produces 6-day forecasts of sulfate, smoke, dust and sea salt aerosol concentrations and visibility for the entire globe. The Coupled Ocean Atmosphere Mesoscale Prediction System (COAMPS (registered) ) is run twice daily for Southwest Asia and produces 3-day forecasts of dust, smoke, and visibility. The graphical output from these models is available on the Internet (www.nrlmry.navy.mil/aerosol/). The aerosol optical properties are calculated for each specie for each forecast output time and used for sea surface temperature (SST) retrieval corrections, regional electro-optical (EO) propagation assessments, and the development of satellite algorithms. NAAPS daily aerosol optical depth (AOD) values are compared with the Advanced Very High Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS) AOD values. Visibility forecasts are compared quantitatively with surface synoptic reports.

  11. Aerosol penetration inside HEPA filtration media

    International Nuclear Information System (INIS)

    Attempts made to modelize changes in high-efficiency particulate air (HEPA) filter pressure drop as a function of such parameters as the amount of aerosol collected, which also take account of filtering medium characteristics, those of the filtered aerosol and the filtration velocity, have always been limited by a lack of knowledge of the distribution of particles within the medium. For the last few years, a method, developed over 25 years ago to study the distribution of Radon daughters within filter media made of cellulose fibers, has been reused and applied to radioactive and fluorescent aerosols penetration studies. This method enables determination of aerosol distribution on the surface and inside the filter medium by peeling away successive layers using an adhesive tape and measuring the specific amounts removed each time. Knowledge of aerosol penetration within the filter has revealed that, for a give aerosol, particle distribution inside the filter rapidly decreased exponentially and that fixation on the filter's front surface rapidly superseded penetration inside the medium. The deposit profiles thus measured have made it possible to propose a model for determining the rate of filter pressure drop increase that closely agrees with experimental results

  12. SCIAMACHY stratospheric aerosol extinction profile retrieval

    Directory of Open Access Journals (Sweden)

    G. Taha

    2010-11-01

    Full Text Available The Ozone Mapper and Profiler Suite Limp Profiler (OMPS/LP algorithm is used to retrieve ozone and aerosol profiles using a series of 120 SCIAMACHY limb measurements collocated with SAGE II solar occultation events. The primary goal of the study is to ascertain the capability of the OMPS/LP retrieval algorithm to accurately retrieve the vertical distribution of stratospheric aerosol extinction coefficient so as to better account for aerosol effects in the ozone profiling retrieval process. Using simulated radiances, we show that the aerosol extinction coefficient can be retrieved from limb scatter measurements within 5% and a standard deviation better than 15%, which is more than sufficient to improve the OMPS/LP ozone products to be used as Environmental Data Records. We also illustrate the ability of SCIAMACHY limb measurements to retrieve stratospheric aerosol profiles with accuracy comparable to other instruments. The retrieved aerosol profiles agree with collocated SAGE II measurements on average to within 25%, with a standard deviation of 35%.

  13. Radiation monitoring by radiation effect of aerosol

    International Nuclear Information System (INIS)

    The high energy and high intensity accelerator facilities need the radiation monitoring with temporal and spatial resolutions. Numerical estimations are made for the radiation monitoring using the sampling method of aerosol Alanine. The aerosol Alanine put into the monitoring area through the duct. The intensity of radicals in the collected throughput Alanine of about 50 mg after passing through the monitoring area is measured by the ESR (Electron Spin Resonance) method. Key parameters in the system are the aerosol particle diameter and its intensity, the duct diameter and length, and the aerosol flow rate inside the duct. The maximum dose rate more than 108 Gy/h is possible to measure assuming the duct of 100 cm2 in area and 10 m in length, and the aerosol flow rate of 1000 L/min. The temporal resolution of the order of minutes is obtainable when the aerosol particle size is 0.1 μm. As a result of numerical estimation based on empirical simulations, it is to be promising to apply a proposed scheme to the radiation monitoring for accelerator fields. (Y. Tanaka)

  14. Investigation on aerosol transport in containment cracks

    International Nuclear Information System (INIS)

    Under severe accident conditions, the containment leak-tightness could be threatened by energetic phenomena that could yield a release to the environment of nuclear aerosols through penetrating concrete cracks. As few data are presently available to quantify this aerosol leakage, a specific action was launched in the framework of the Santar Project of the European 6th Framework Programme. In this context, both theoretical and experimental investigations have been managed to develop a model that can readily be applied within a code like Aster (Accident Source Term Evaluation Code). Particle diffusion, settling, turbulent deposition, diffusiophoresis and thermophoresis have been considered as deposition mechanisms inside the crack path. They have been encapsulated in numerical models set up to reproduce experiments with small tubes and capillaries and simulate the plug formation. Then, an original lagrangian approach has been used to evaluate the crack retention under typical PWR accident conditions, comparing its predictions with those given by the eulerian approach implemented in the ECART code. On the experimental side, the paper illustrates an aerosol production and measurement system developed to validate aerosol deposition models into cracks and the results that can be obtained: a series of tests were performed with monodispersed fluorescein aerosols injected into a cracked concrete sample. A key result that should be further explored refers to the high enhancement of aerosol retention that could be due to steam condensation. Recommendations concerning future experimentation are also given in the paper. (author)

  15. Aerosols, clouds and their climatic impacts

    Energy Technology Data Exchange (ETDEWEB)

    Kulmala, M.; Laaksonen, A.; Korhonen, P. [Helsinki Univ. (Finland). Dept. of Physics

    1995-12-31

    The increasing atmospheric concentrations of greenhouse gases such as carbon dioxide and methane may drive a significant warming of the earth`s climate. However, a topic of more recent attention is the possibility that increased atmospheric concentrations of aerosol particles might drive a cooling of the planet. There are two distinct cooling mechanisms related to the enhanced concentrations of aerosol particles: the increase in the direct reflection of solar radiation (the direct effect), and the increase in cloud reflectivity caused by greater numbers of cloud condensation nuclei available (the indirect effect). Aerosols and clouds play a major role in the scattering and absorption of radiation in the Earth`s atmosphere. Locally the net effect can vary because of different kinds of surfaces. But according to measurements, the global net effect of clouds (and aerosols) on the atmosphere is net cooling and thus in opposition to the effect of greenhouse gases. The prediction of the future evolution of the climate involves substantial uncertainties. Clouds have a major effect on the radiation balance of the Earth and the prediction of amount and radiative properties of clouds is very difficult. Also the formation mechanisms and residence times of aerosol particles in the atmosphere involve large uncertainties. Thus the most serious difficulties arise in the area of the physics of clouds and aerosols

  16. Physical properties of aerosols at Maitri, Antarctica

    Indian Academy of Sciences (India)

    C G Deshpande; A K Kamra

    2004-03-01

    Measurements of the submicron aerosol size distribution made at the Indian Antarctic station, Maitri (70° 45′S, 11° 44′E) from January 10th to February 24th, 1997, are reported. Total aerosol concentrations normally range from 800 to 1200 particles cm-3 which are typical values for the coastal stations at Antarctica in summer. Aerosol size distributions are generally trimodal and open- ended with a peak between 75 and 133nm and two minima at 42 and 420 nm. Size distributions remain almost similar for several hours or even days in absence of any meteorological disturbance. Total aerosol concentration increases by approximately an order of magnitude whenever a low pressure system passes over the station. Based on the evolution of aerosol size-distributions during such aerosol enhancement periods, three types of cases have been identified. The nucleation mode in all three cases has been suggested to result from the photochemical conversion of the DMS emissions transported either by the marine air or by the air from the ice-melt regions around Maitri. Subsidence of midtropospheric air during the weakening of radiative inversion is suggested as a possible source of the nucleation mode particles in the third case. Growth of the nucleation mode particles by condensation, coagulation and/or by cloud processes has been suggested to be responsible for other modes in size distributions.

  17. Aerosol and air pollution size distribution

    Science.gov (United States)

    Shani, Gad; Haccoun, A.; Kushelevsky, A.

    The size distribution of aerosols was measured in a moderately industrial city, in a semi-arid zone on the Negev desert border. The aerosols in the city of Beer Sheva are from two sources: the dust coming from the desert and urban pollution. The size measurements were done with a cascade impactor. The elemental content of the aerosols was investigated by neutron activation analysis and X-ray fluorescence. The main elements of the dust are: Ca, Si, Fe, Na and the trace elements are: Sc, Se, La, Sm, Hf and others. The main elements of the urban pollution are S, Br, Pb, Cl, Hg and others. It was found that the elements belonging to each group can easily be classified by the size distribution. The analytical consideration of the aerosol size distribution of each group are discussed and two corresponding analytical expressions are suggested. It is shown that aerosols originating in the dust have a hump shape distribution around ~ 4μm, and those originating in urban pollution have a distribution decreasing with increasing aerosol diameter. Many examples are given to prove the conclusions.

  18. Study of photolytic aerosols at stratospheric pressures

    International Nuclear Information System (INIS)

    An experimental study of photolytic aerosol formation at stratospheric pressure (60 Torr) and laboratory temperature, was carried out previous to the exact simulation of photolytic aerosol formation in real stratospheric conditions. An experimental simulation device, techniques of generation of known mixtures of inert gases with SO2 and NOsub(x) traces at low concentration (below 1 ppm volume) and H2O traces (a few ppm), and techniques for the determination and counting of aerosol particles at low pressures were perfected. The following results were achieved: the rate of vapor condensation on nuclei was reduced when total pressure decreased. At low pressure the working of condensation nuclei counters and the formation of photolytic aerosols is influenced by this phenomenon. An explanation is proposed, as well as means to avoid this unpleasant effect on the working of nuclei counters at low pressure. No photolytic aerosol production was ascertained at 60 Torr when water concentration was below 100 ppm whatever the concentration of SO2 or NOsub(x) traces. With water concentration below 1200ppm and SO2 trace concentration below 1ppm, the aerosol particles produced could not consist of sulfuric acid drops but probably of nitrosyl sulfate acide crystals

  19. The aerosol penetration through an electret fibrous filter

    Institute of Scientific and Technical Information of China (English)

    Jiang Wei; Cheung Chun-Shun; Chan Cheong-Ki; Zhu Chao

    2006-01-01

    The aim of this paper is to present a theoretical study of the aerosol penetration through an electret fibrous filter, using a numerical approach. The aerosol sizes considered in this study were in the submicron range, and in the numerical model, the conventional mechanical mechanisms (impaction, interception, diffusion and gravitationally settling) were taken into consideration along with the electrostatic mechanisms, including the Coulombic and dielectrophoretic effects. The aerosol penetration through an electret fibrous filter is heavily dependent on the aerosol penetration of a single fibre. The aerosol penetration through a single electret fibre under various filtration conditions was calculated. The effects of aerosol diameter, aerosol and fibre charge state, face velocity, packing density and aerosol dielectric constant on the aerosol penetration were investigated.

  20. Aerosol-Based Cell Therapy for Treatment of Lung Diseases.

    Science.gov (United States)

    Kardia, Egi; Halim, Nur Shuhaidatul Sarmiza Abdul; Yahaya, Badrul Hisham

    2016-01-01

    Aerosol-based cell delivery technique via intratracheal is an effective route for delivering transplant cells directly into the lungs. An aerosol device known as the MicroSprayer(®) Aerosolizer is invented to transform liquid into an aerosol form, which then can be applied via intratracheal administration for drug delivery. The device produces a uniform and concentrated distribution of aerosolized liquid. Using the capability of MicroSprayer(®) Aerosolizer to transform liquid into aerosol form, our group has designed a novel method of cell delivery using an aerosol-based technique. We have successfully delivered skin-derived fibroblast cells and airway epithelial cells into the airway of a rabbit with minimum risk of cell loss and have uniformly distributed the cells into the airway. This chapter illustrates the application of aerosol device to deliver any type of cells for future treatment of lung diseases. PMID:27062596

  1. Monitoreo de parásitos en efluentes domiciliarios

    OpenAIRE

    Liliana Semenas; Norma Brugni; Gustavo Viozzi; Ana Kreiter

    1999-01-01

    OBJETIVO: Evaluar la presencia de parásitos en efluentes semisólidos y líquidos en distintas localidades de la Patagonia argentina considerando que ésta es una de las restricciones para su uso. MÉTODOS: Las muestras tomadas en 4 Plantas de Tratamiento de Efluentes Domiciliarios se analizaron siguiendo las normativas de Environmental Protection Agency, Organización Mundial de la Salud, Standard Methods for Examination of Water and Wastewater y de algunas clasificaciones. RESULTADOS: Solamente ...

  2. Inspecciones París MOU y normas reguladoras

    OpenAIRE

    Díaz Pujol, María del Carmen

    2013-01-01

    Este proyecto trata fundamentalmente del control del Estado rector del puerto que desarrollan los Estados miembros del Memorando de París. El texto se compone de cinco capítulos a lo largo de los que se abordan las siguientes cuestiones: El capítulo primero da un repaso a la importancia que revisten las normas sobre seguridad marítima y prevención de la contaminación marina, a la vez que expone la cuestión relativa a la responsabilidad de su aplicación y de su cumplimiento, recordando q...

  3. Alex: incluir la parálisis cerebral

    OpenAIRE

    Ayuela Fernández, Mª del Mar

    2013-01-01

    El presente trabajo se basa en un estudio de caso: Alex. Un niño con una parálisis cerebral tipo espástico y su inclusión, bajo el proceso de enseñanza-aprendizaje durante el curso 2012-2013 en dos escenarios: familia y colegio. En un primer momento señalaremos los objetivos planteados a raíz de los interrogantes que nos suscita el trabajar con niños y niñas con necesidades educativas especiales. Posteriormente y tras un encuadre teórico y metodológico, abordaremos una propuesta de intervenci...

  4. Videojuego adaptado para personas con parálisis cerebral

    OpenAIRE

    Gómez Davó, Roberto

    2014-01-01

    La parálisis cerebral describe un grupo de trastornos del desarrollo psicomotor, que causan una limitación de la actividad de la persona, es decir, es un padecimiento que principalmente se caracteriza por la inhabilidad de poder controlar completamente las funciones del sistema motor. Esto puede incluir espasmos o rigidez en los músculos, movimientos involuntarios, y/o trastornos en la postura o movilidad del cuerpo. Estos trastornos psicomotores imposibilitan su interacción con los sistemas ...

  5. INCORPORATION DU PHOSPHORE DANS CdTe PAR RECUIT LASER

    OpenAIRE

    Uzan, C.; Legros, R.; Marfaing, Y.

    1983-01-01

    La méthode du recuit laser a été utilisée pour incorporer du phosphore dans CdTe à partir d'une couche de Cd3P2 déposée en surface. La caractérisation par photoluminescence et mesure de profil à l'analyseur ionique montre le caractère actif du phosphore introduit et permet d'évaluer à 1018cm-3 la concentration atteinte à 1 µm de profondeur.

  6. INNOVATIONS ET GOUVERNANCE TERRITORIALE : UNE ANALYSE PAR LES DISPOSITIFS

    OpenAIRE

    Soulard, Christophe-Toussaint; Mathé, Syndhia; Michel, Laura; Nougaredes, Brigitte; Jarrige, Françoise; Maurel, Pierre; Clement, Camille; Martinand, Pierre; Guiheneuf, Pierre-Yves; Barbe, Eric

    2010-01-01

    Cette communication vise à présenter les outils méthodologiques d’analyse/évaluation de la gouvernance territoriale élaborés dans le cadre du projet de recherche PSDR Gouv.Innov sur les innovations organisationnelles relatives à la gouvernance territoriale. Il s’agit d’étudier les transformations introduites par les politiques de développement durable au niveau des dispositifs de gouvernance territoriale visant à favoriser une gestion intégrée des espaces ruraux. Dans un contexte de recomposi...

  7. Innovation et gouvernance territoriale : une analyse par les dispositifs

    OpenAIRE

    Rey Valette, H.; Chia, E; Soulard, C.; Mathé, S.; Michel, L.; Nougaredes, B.; Jarrige, F.; Maurel, P.; Clement, C.; Martinand, P.; Guiheneuf, P.Y.; Barbe, E.

    2010-01-01

    International audience Cette communication vise à présenter les outils méthodologiques d'analyse/évaluation de la gouvernance territoriale élaborés dans le cadre du projet de recherche PSDR Gouv.Innov sur les innovations organisationnelles relatives à la gouvernance territoriale. Il s'agit d'étudier les transformations introduites par les politiques de développement durable au niveau des dispositifs de gouvernance territoriale visant à favoriser une gestion intégrée des espaces ruraux. Dan...

  8. An AERONET-based aerosol classification using the Mahalanobis distance

    Science.gov (United States)

    Hamill, Patrick; Giordano, Marco; Ward, Carolyne; Giles, David; Holben, Brent

    2016-09-01

    We present an aerosol classification based on AERONET aerosol data from 1993 to 2012. We used the AERONET Level 2.0 almucantar aerosol retrieval products to define several reference aerosol clusters which are characteristic of the following general aerosol types: Urban-Industrial, Biomass Burning, Mixed Aerosol, Dust, and Maritime. The classification of a particular aerosol observation as one of these aerosol types is determined by its five-dimensional Mahalanobis distance to each reference cluster. We have calculated the fractional aerosol type distribution at 190 AERONET sites, as well as the monthly variation in aerosol type at those locations. The results are presented on a global map and individually in the supplementary material. Our aerosol typing is based on recognizing that different geographic regions exhibit characteristic aerosol types. To generate reference clusters we only keep data points that lie within a Mahalanobis distance of 2 from the centroid. Our aerosol characterization is based on the AERONET retrieved quantities, therefore it does not include low optical depth values. The analysis is based on "point sources" (the AERONET sites) rather than globally distributed values. The classifications obtained will be useful in interpreting aerosol retrievals from satellite borne instruments.

  9. Genesis of elevated aerosol loading over the Indian region

    Science.gov (United States)

    Prijith, S. S.; Rao, P. V. N.; Mohan, Mannil

    2016-05-01

    Elevated aerosols assume importance as the diabatic heating due to aerosol absorption is more intense at higher altitudes where the atmosphere becomes thinner. Indian region, especially its central and northern latitudes, experiences significant loading of elevated aerosols during pre-monsoon and summer months. Genesis of elevated aerosol loading over Indian region is investigated in the present study, using multi-year satellite observations from Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) and Moderate Resolution Imaging Spectroradiometer (MODIS) along with reanalysis winds from MERRA. Central India is observed to have prominent aerosols loading at higher altitudes during pre-monsoon season, whereas it is during summer months over north-west India. Further analysis reveals that the elevated aerosols over Indian region in pre-monsoon and summer months are significantly contributed by transported mineral dust from the arid continental regions at west. In addition to the mineral dust advection, aerosols at higher altitudes over Indian region are enriched by strong convection and associated vertical transport of surface level aerosols. Vertical transport of aerosols observed over Indian region during pre-monsoon and summer months is aided by intense convergence at the surface level and divergence at the upper level. Moreover, aerosol source/sink strength estimated using aerosol flux continuity equation show significant aerosol production over central India during pre-monsoon. Strong vertical transport prevails during pre-monsoon uplifts the locally produced aerosols, with considerable anthropogenic fraction, to higher altitudes where their impacts would be more intense.

  10. Paracrine Apoptotic Effect of p53 Mediated by Tumor Suppressor Par-4

    Directory of Open Access Journals (Sweden)

    Ravshan Burikhanov

    2014-01-01

    Full Text Available The guardian of the genome, p53, is often mutated in cancer and may contribute to therapeutic resistance. Given that p53 is intact and functional in normal tissues, we harnessed its potential to inhibit the growth of p53-deficient cancer cells. Specific activation of p53 in normal fibroblasts selectively induced apoptosis in p53-deficient cancer cells. This paracrine effect was mediated by p53-dependent secretion of the tumor suppressor Par-4. Accordingly, the activation of p53 in normal mice, but not p53−/− or Par-4−/− mice, caused systemic elevation of Par-4, which induced apoptosis of p53-deficient tumor cells. Mechanistically, p53 induced Par-4 secretion by suppressing the expression of its binding partner, UACA, which sequesters Par-4. Thus, normal cells can be empowered by p53 activation to induce Par-4 secretion for the inhibition of therapy-resistant tumors.

  11. Chemical characterization of secondary organic aerosol constituents from isoprene ozonolysis in the presence of acidic aerosol

    Science.gov (United States)

    Riva, Matthieu; Budisulistiorini, Sri Hapsari; Zhang, Zhenfa; Gold, Avram; Surratt, Jason D.

    2016-04-01

    Isoprene is the most abundant non-methane hydrocarbon emitted into Earth's atmosphere and is predominantly derived from terrestrial vegetation. Prior studies have focused largely on the hydroxyl (OH) radical-initiated oxidation of isoprene and have demonstrated that highly oxidized compounds, such as isoprene-derived epoxides, enhance the formation of secondary organic aerosol (SOA) through heterogeneous (multiphase) reactions on acidified sulfate aerosol. However, studies on the impact of acidified sulfate aerosol on SOA formation from isoprene ozonolysis are lacking and the current work systematically examines this reaction. SOA was generated in an indoor smog chamber from isoprene ozonolysis under dark conditions in the presence of non-acidified or acidified sulfate seed aerosol. The effect of OH radicals on SOA chemical composition was investigated using diethyl ether as an OH radical scavenger. Aerosols were collected and chemically characterized by ultra performance liquid chromatography/electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-QTOFMS) and gas chromatography/electron impact ionization-mass spectrometry (GC/EI-MS). Analysis revealed the formation of highly oxidized compounds, including organosulfates (OSs) and 2-methylterols, which were significantly enhanced in the presence of acidified sulfate seed aerosol. OSs identified in the chamber experiments were also observed and quantified in summertime fine aerosol collected from two rural locations in the southeastern United States during the 2013 Southern Oxidant and Aerosol Study (SOAS).

  12. Effect of Aerosol Size and Hygroscopicity on Aerosol Optical Depth in the Southeastern United States

    Science.gov (United States)

    Brock, Charles; Wagner, Nick; Gordon, Timothy

    2016-04-01

    Aerosol optical depth (AOD) is affected by the size, optical characteristics, and hygroscopicity of particles, confounding attempts to link remote sensing observations of AOD to measured or modeled aerosol mass concentrations. In situ airborne observations of aerosol optical, chemical, microphysical and hygroscopic properties were made in the southeastern United States in the daytime in summer 2013. We use these observations to constrain a simple model that is used to test the sensitivity of AOD to the various measured parameters. As expected, the AOD was found to be most sensitive to aerosol mass concentration and to aerosol water content, which is controlled by aerosol hygroscopicity and the ambient relative humidity. However, AOD was also fairly sensitive to the mean particle diameter and the width of the size distribution. These parameters are often prescribed in global models that use simplified modal parameterizations to describe the aerosol, suggesting that the values chosen could substantially bias the calculated relationship between aerosol mass and optical extinction, AOD, and radiative forcing.

  13. Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds

    Energy Technology Data Exchange (ETDEWEB)

    Turner, David, D.; Ferrare, Richard, A.

    2011-07-06

    The 'Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds' project focused extensively on the analysis and utilization of water vapor and aerosol profiles derived from the ARM Raman lidar at the Southern Great Plains ARM site. A wide range of different tasks were performed during this project, all of which improved quality of the data products derived from the lidar or advanced the understanding of atmospheric processes over the site. These activities included: upgrading the Raman lidar to improve its sensitivity; participating in field experiments to validate the lidar aerosol and water vapor retrievals; using the lidar aerosol profiles to evaluate the accuracy of the vertical distribution of aerosols in global aerosol model simulations; examining the correlation between relative humidity and aerosol extinction, and how these change, due to horizontal distance away from cumulus clouds; inferring boundary layer turbulence structure in convective boundary layers from the high-time-resolution lidar water vapor measurements; retrieving cumulus entrainment rates in boundary layer cumulus clouds; and participating in a field experiment that provided data to help validate both the entrainment rate retrievals and the turbulent profiles derived from lidar observations.

  14. Method of measuring aerosol particles using automated mobility-classified aerosol detector

    OpenAIRE

    Russell, Lynn M.; Flagan, Richard C.; Zhang, Shou-Hua

    1999-01-01

    An aerosol detection system for measuring particle number distribution with respect to particle dimension in an aerosol sample. The system includes an alternating dual-bag sampler, a radially classified differential mobility analyzer, and a condensation nucleus counter. Pressure variations in sampling are compensated by feedback control of volumetric flow rates.

  15. Characterization of urban aerosol using aerosol mass spectrometry and proton nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Cleveland, M. J.; Ziemba, L. D.; Griffin, R. J.; Dibb, J. E.; Anderson, C. H.; Lefer, B.; Rappenglück, B.

    2012-07-01

    Particulate matter was measured during August and September of 2006 in Houston as part of the Texas Air Quality Study II Radical and Aerosol Measurement Project. Aerosol size and composition were determined using an Aerodyne quadrupole aerosol mass spectrometer. Aerosol was dominated by sulfate (4.1 ± 2.6 μg m-3) and organic material (5.5 ± 4.0 μg m-3), with contributions of organic material from both primary (˜32%) and secondary (˜68%) sources. Secondary organic aerosol appears to be formed locally. In addition, 29 aerosol filter samples were analyzed using proton nuclear magnetic resonance (1H NMR) spectroscopy to determine relative concentrations of organic functional groups. Houston aerosols are less oxidized than those observed elsewhere, with smaller relative contributions of carbon-oxygen double bonds. These particles do not fit 1H NMR source apportionment fingerprints for identification of secondary, marine, and biomass burning organic aerosol, suggesting that a new fingerprint for highly urbanized and industrially influenced locations be established.

  16. Possible Relations between Organic Aerosol Analysed by Aerosol Mass Spetrometer and EC/OC Analyzer

    Czech Academy of Sciences Publication Activity Database

    Vodička, Petr; Makeš, Otakar; Kubelová, Lucie; Schwarz, Jaroslav; Ždímal, Vladimír

    - : -, 2015, 234 /2053/. ISBN N. [Goldschmidt Conference /25./. Prague (CZ), 16.08.2015-21.08.2015] R&D Projects: GA ČR GAP209/11/1342 EU Projects: European Commission(XE) H2020:654109 Institutional support: RVO:67985858 Keywords : carbonaceous aerosols * aerosol data * analyzer Subject RIV: CF - Physical ; Theoretical Chemistry

  17. Evaluation of the discmini personal aerosol monitor for submicrometer sodium chloride and metal aerosols

    Science.gov (United States)

    Mills, Jessica Breyan

    This work evaluated the robust, lightweight DiSCmini (DM) aerosol monitor for its ability to measure the concentration and mean diameter of submicrometer aerosols. Tests were conducted with monodispersed and polydispersed aerosols composed of two particle types (sodium chloride, NaCl, and spark generated metal particles, which simulate particles found in welding fume) at three different steady-state concentration ranges (Low, 104 particles/cm3). Particle number concentration, lung deposited surface area (LDSA) concentration, and mean size measured with the DM were compared to those measured with reference instruments, a scanning mobility particle sizer (SMPS) and a handheld condensation particle counter (CPC). Particle number concentrations measured with the DM were within 16% of those measured by the CPC for polydispersed aerosols. Poorer agreement was observed for monodispersed aerosols (+/-35% for most tests and +101% for 300-nm NaCl). LDSA concentrations measured by the DM were 96% to 155% of those estimated with the SMPS. The geometric mean diameters measured with the DM were within 30% of those measured with the SMPS for monodispersed aerosols and within 25% for polydispersed aerosols (except for the case when the aerosol contained a substantial number of particles larger than 300 nm). The accuracy of the DM is reasonable for particles smaller than 300 nm but caution should be exercised when particles larger than 300 nm are present.

  18. The DRAGON aerosol research facility to study aerosol behaviour for reactor safety applications

    International Nuclear Information System (INIS)

    During a severe accident in a nuclear power plant fission products are expected to be released in form of aerosol particles and droplets. To study the behaviour of safety relevant reactor components under aerosol loads and prototypical severe accident conditions the multi-purpose aerosol generation facility DRAGON is used since 1994 for several projects. DRAGON can generate aerosol particles by the evaporation-condensation technique using a plasma torch system, fluidized bed and atomization of particles suspended in a liquid. Soluble, hygroscopic aerosol (i.e. CsOH) and insoluble aerosol particles (i.e. SnO2, TiO2) or mixtures of them can be used. DRAGON uses state-of-the-art thermal-hydraulic, data acquisition and aerosol measurement techniques and is mainly composed of a mixing chamber, the plasma torch system, a steam generator, nitrogen gas and compressed air delivery systems, several aerosol delivery piping, gas heaters and several auxiliary systems to provide vacuum, coolant and off-gas treatment. The facility can be operated at system pressure of 5 bars, temperatures of 300 deg. C, flow rates of non-condensable gas of 900 kg/h and steam of 270 kg/h, respectively. A test section under investigation is attached to DRAGON. The paper summarizes and demonstrates with the help of two project examples the capabilities of DRAGON for reactor safety studies. (authors)

  19. Atmospheric aerosols: Their Optical Properties and Effects (supplement)

    Science.gov (United States)

    1976-01-01

    A digest of technical papers is presented. Topics include aerosol size distribution from spectral attenuation with scattering measurements; comparison of extinction and backscattering coefficients for measured and analytic stratospheric aerosol size distributions; using hybrid methods to solve problems in radiative transfer and in multiple scattering; blue moon phenomena; absorption refractive index of aerosols in the Denver pollution cloud; a two dimensional stratospheric model of the dispersion of aerosols from the Fuego volcanic eruption; the variation of the aerosol volume to light scattering coefficient; spectrophone in situ measurements of the absorption of visible light by aerosols; a reassessment of the Krakatoa volcanic turbidity, and multiple scattering in the sky radiance.

  20. The double par locus of virulence factor pB171: DNA segregation is correlated with oscillation of ParA

    DEFF Research Database (Denmark)

    Ebersbach, G; Gerdes, K; Charbon, Gitte Ebersbach

    2001-01-01

    Prokaryotic plasmids and chromosomes encode partitioning (par) loci that segregate DNA to daughter cells before cell division. Recent database analyses showed that almost all known par loci encode an ATPase and a DNA-binding protein, and one or more cis-acting regions where the proteins act. All ...... simultaneously abolished plasmid stabilization and ParA-Gfp oscillation. These observations raise the possibility that ParA oscillation is prerequisite for active plasmid segregation.......Prokaryotic plasmids and chromosomes encode partitioning (par) loci that segregate DNA to daughter cells before cell division. Recent database analyses showed that almost all known par loci encode an ATPase and a DNA-binding protein, and one or more cis-acting regions where the proteins act. All...... Type II locus. Separately, each locus stabilized a test-plasmid efficiently. Together, the two loci mediated even more efficient plasmid stabilization. The par loci have a unique genetic organization in that they share a common central region at which the two different DNA-binding proteins probably act...

  1. 秦岭南北地区光合有效辐射时空变化及突变特征%Distribution and change of Photosynthetically Active Radiation (PAR) in the northern and southern regions of Qinling Mountains, China

    Institute of Scientific and Technical Information of China (English)

    蒋冲; 朱枫; 杨陈; 王飞; 穆兴民; 李锐

    2013-01-01

    Mountain Areas (VBW). PAR in summer was the highest, followed by spring, autumn and winter. The distribution of PAR in spring, autumn and winter showed the same spatial pattern as annual PAR, but in summer, PAR in NQ is also the highest, then HB and VBW, and SQ being the lowest one. (2) PAR declined significantly in past 52a, the declining rates became smaller from south and east part to north and west part of this region. Except for an insignificant increase in spring, PAR decreased in other seasons, and the rate in summer was fastest, followed by that in winter and autumn. The maximum and minimum PAR appeared in 1960s-1970s and 2000s respectively in spring, summer and autumn. There were almost half of stations showing an increase of PAR mainly in west and central parts, and the other half stations showing decrease in spring. PAR of 79% of stations decreased in autumn, and the increasing stations were also located in west and central parts. PAR in summer and winter declined in most stations, and the decreasing rate was bigger in south part of Qingling Mountains than in north part. (3) 89% of stations had abrupt change points of yearly and summer PAR, and about 85% and 90% of them happened between 1979 and 1983, respectively. There were no obvious abrupt change points in spring or autumn. (4) Climate change (wind speed declining), fast urbanization and more aerosol emission from industrial production were the main reasons for the continuous decline of PAR, and the aerosol emitted from volcanoes was the main reason for fluctuation of PAR.

  2. Localization of the ParC protein in Escherichia coli cells

    OpenAIRE

    2007-01-01

    The Escherichia coli ParC protein is one of two subunits of the topoisomerase IV, a type II topoisomerase. Topo IV is responsible for relaxing positive supercoils and decatenating linked daughter chromosomes after replication. This is done by introducing transient double-stranded breaks into the DNA, passing through a segment of uncut duplex DNA, before resealing the break. Mutations in parC lead to the par phenotype which is characterized by chromosomes that can replicate but are deficient i...

  3. Utilisation rationnelle de l'énergie par les techniques de stockage et de transport du froid par chaleur latente

    OpenAIRE

    Bédécarrats, Jean-Pierre

    2010-01-01

    Les contraintes environnementales de plus en plus fortes ainsi que les problèmes grandissants de la disponibilité des ressources énergétiques obligent le secteur de l'énergie non seulement à une évolution importante de ses technologies mais aussi à leurs utilisations plus rationnelles. Ce mémoire présente la synthèse de mes initiatives de recherches menées sur le stockage et le transport de l'énergie par chaleur latente essentiellement dans le domaine du froid. Les Matériaux à Changement de P...

  4. Note: Design and development of wireless controlled aerosol sampling network for large scale aerosol dispersion experiments

    Science.gov (United States)

    Gopalakrishnan, V.; Subramanian, V.; Baskaran, R.; Venkatraman, B.

    2015-07-01

    Wireless based custom built aerosol sampling network is designed, developed, and implemented for environmental aerosol sampling. These aerosol sampling systems are used in field measurement campaign, in which sodium aerosol dispersion experiments have been conducted as a part of environmental impact studies related to sodium cooled fast reactor. The sampling network contains 40 aerosol sampling units and each contains custom built sampling head and the wireless control networking designed with Programmable System on Chip (PSoC™) and Xbee Pro RF modules. The base station control is designed using graphical programming language LabView. The sampling network is programmed to operate in a preset time and the running status of the samplers in the network is visualized from the base station. The system is developed in such a way that it can be used for any other environment sampling system deployed in wide area and uneven terrain where manual operation is difficult due to the requirement of simultaneous operation and status logging.

  5. Containment aerosol behaviour simulation studies in the BARC nuclear aerosol test facility

    International Nuclear Information System (INIS)

    A Nuclear Aerosol Test Facility (NATF) has been built and commissioned at Bhabha Atomic Research Centre to carry out simulation studies on the behaviour of aerosols released into the reactor containment under accident conditions. This report also discusses some new experimental techniques for estimation of density of metallic aggregates. The experimental studies have shown that the dynamic densities of aerosol aggregates are far lower than their material densities as expected by the well-known fractal theory of aggregates. In the context of codes, this has significant bearing in providing a mechanistic basis for the input density parameter used in estimating the aerosol evolution characteristics. The data generated under the quiescent and turbulent conditions and the information on aggregate densities are now being subjected to the validation of the aerosol behaviour codes. (author)

  6. MORPHOLOGY OF BLACK CARBON AEROSOLS AND UBIQUITY OF 50-NANOMETER BLACK CARBON AEROSOLS IN THE ATMOSPHERE

    Institute of Scientific and Technical Information of China (English)

    Fengfu Fu; Liangjun Xu; Wei Ye; Yiquan Chen; Mingyu Jiang; Xueqin Xu

    2006-01-01

    Different-sized aerosols were collected by an Andersen air sampler to observe the detailed morphology of the black carbon (BC) aerosols which were separated chemically from the other accompanying aerosols, using a Scanning Electron Microscope equipped with an Energy Dispersive X-ray Spectrometer (SEM-EDX). The results indicate that most BC aerosols are spherical particles of about 50 nm in diameter and with a homogeneous surface. Results also show that these particles aggregate with other aerosols or with themselves to form larger agglomerates in the micrometer range. The shape of these 50-nm BC spherical particles was found to be very similar to that of BC particles released from petroleum-powered vehicular internal combustion engines. These spherical BC particles were shown to be different from the previously reported fullerenes found using Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF-MS).

  7. Note: Design and development of wireless controlled aerosol sampling network for large scale aerosol dispersion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Gopalakrishnan, V.; Subramanian, V.; Baskaran, R.; Venkatraman, B. [Radiation Impact Assessment Section, Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)

    2015-07-15

    Wireless based custom built aerosol sampling network is designed, developed, and implemented for environmental aerosol sampling. These aerosol sampling systems are used in field measurement campaign, in which sodium aerosol dispersion experiments have been conducted as a part of environmental impact studies related to sodium cooled fast reactor. The sampling network contains 40 aerosol sampling units and each contains custom built sampling head and the wireless control networking designed with Programmable System on Chip (PSoC™) and Xbee Pro RF modules. The base station control is designed using graphical programming language LabView. The sampling network is programmed to operate in a preset time and the running status of the samplers in the network is visualized from the base station. The system is developed in such a way that it can be used for any other environment sampling system deployed in wide area and uneven terrain where manual operation is difficult due to the requirement of simultaneous operation and status logging.

  8. Note: Design and development of wireless controlled aerosol sampling network for large scale aerosol dispersion experiments

    International Nuclear Information System (INIS)

    Wireless based custom built aerosol sampling network is designed, developed, and implemented for environmental aerosol sampling. These aerosol sampling systems are used in field measurement campaign, in which sodium aerosol dispersion experiments have been conducted as a part of environmental impact studies related to sodium cooled fast reactor. The sampling network contains 40 aerosol sampling units and each contains custom built sampling head and the wireless control networking designed with Programmable System on Chip (PSoC™) and Xbee Pro RF modules. The base station control is designed using graphical programming language LabView. The sampling network is programmed to operate in a preset time and the running status of the samplers in the network is visualized from the base station. The system is developed in such a way that it can be used for any other environment sampling system deployed in wide area and uneven terrain where manual operation is difficult due to the requirement of simultaneous operation and status logging

  9. Stress reactions involving the pars interarticularis in young athletes

    International Nuclear Information System (INIS)

    A stress reaction involving the pars interarticularis of the lumbar spine was confirmed in seven young athletes with a positive technetium pyrophosphate bone scan. No pars defects were detectable on their lumbosacral roentgenograms, which included oblique views. The return to normal levels of radioactive uptake on repeat bone scans correlated closely with their clinical course. If the bony reaction is recognized early, it may heal at a subroentgenographic level and prevent the development of lumbar spondylolysis. These early lesions usually show unilateral increased uptake at one lumbar level on the bone scan and, initially, the athlete localizes the pain to the corresponding unilateral lumbar paraspinous area. The ''one-legged hyperextension test'' is positive on the ipsilateral side and aggravates the pain. Treatment consists of avoiding the aggravating activities and resting. The average time for return to pain-free competition was 7.3 months. These developing defects may be the source of considerable prolonged disability in the young athlete, particularly if undiagnosed and untreated

  10. Four cases of endophthalmitis after 25-gauge pars plana vitrectomy

    Directory of Open Access Journals (Sweden)

    Mutoh T

    2012-08-01

    Full Text Available Tetsuya Mutoh, Koji Kadoya, Makoto ChikudaDepartment of Ophthalmology, Dokkyo Medical University Koshigaya Hospital, Koshigaya, Saitama, JapanAbstract: We report our recent experience with four cases of endophthalmitis (one male, three females after 25-gauge pars plana vitrectomy (PPV. One was a case of persistent cystoid macular edema caused by branch retinal vein occlusion, whereas the remaining three were cases of epiretinal membrane. Preoperative antibiotics before the first PPV procedure were not administered in three of the four cases. Endophthalmitis occurred 2–4 days after the first procedure in all cases, for which ceftazidime 2.0 mg/0.1 mL and vancomycin 1.0 mg/0.1 mL were injected into the vitreous cavity. This was followed by emergent 20-gauge PPV and intraocular lens removal using an infusion fluid containing ceftazidime and vancomycin. After the second PPV procedure, progress was good in three cases while retinal detachment occurred in the remaining case one month after surgery; this case required a third PPV procedure. Final best-corrected visual acuity ranged from 20/100 to 20/25 for the four cases. Bacterial cultures were negative after the second PPV procedure in all cases. In conclusion, postoperative endophthalmitis occurred in four of 502 cases (0.80% that underwent 25-gauge PPV at our hospital. It is important to minimize the incidence of endophthalmitis after 25-gauge PPV.Keywords: 25-gauge pars plana vitrectomy, endophthalmitis, incidence

  11. Urokinase-type plasminogen activator receptor (uPAR) as a promising new imaging target

    DEFF Research Database (Denmark)

    Persson, Morten; Kjaer, Andreas

    2013-01-01

    Urokinase-type plasminogen activator receptor (uPAR) has been shown to be of special importance during cancer invasion and metastasis. However, currently, tissue samples are needed for measurement of uPAR expression limiting the potential as a clinical routine. Therefore, non-invasive methods are...... the cell surface. Due to the importance of uPAR in cancer invasion and metastasis, a number of high-affinity ligands have been identified during the last decades. These ligands have recently been used as starting point for the development of a number of ligands for imaging of uPAR using various...

  12. Structural and genetic analyses of a par locus that regulates plasmid partition in Bacillus subtilis.

    OpenAIRE

    Chang, S.; Chang, S Y; Gray, O

    1987-01-01

    The Bacillus plasmid pLS11 partitions faithfully during cell division. Using a partition-deficient plasmid vector, we randomly cloned DNA fragments of plasmid pLS11 and identified the locus that regulates plasmid partition (par) by cis complementation in Bacillus subtilis. The cloned par gene conferred upon the vector plasmid a high degree of segregational stability. The par locus was mapped to a 167-base-pair segment on pLS11, and its nucleotide sequence was determined. The cloned par fragme...

  13. New satellite project Aerosol-UA: Remote sensing of aerosols in the terrestrial atmosphere

    Science.gov (United States)

    Milinevsky, G.; Yatskiv, Ya.; Degtyaryov, O.; Syniavskyi, I.; Mishchenko, M.; Rosenbush, V.; Ivanov, Yu.; Makarov, A.; Bovchaliuk, A.; Danylevsky, V.; Sosonkin, M.; Moskalov, S.; Bovchaliuk, V.; Lukenyuk, A.; Shymkiv, A.; Udodov, E.

    2016-06-01

    We discuss the development of the Ukrainian space project Aerosol-UA which has the following three main objectives: (1) to monitor the spatial distribution of key characteristics of terrestrial tropospheric and stratospheric aerosols; (2) to provide a comprehensive observational database enabling accurate quantitative estimates of the aerosol contribution to the energy budget of the climate system; and (3) quantify the contribution of anthropogenic aerosols to climate and ecological processes. The remote sensing concept of the project is based on precise orbital measurements of the intensity and polarization of sunlight scattered by the atmosphere and the surface with a scanning polarimeter accompanied by a wide-angle multispectral imager-polarimeter. Preparations have already been made for the development of the instrument suite for the Aerosol-UA project, in particular, of the multi-channel scanning polarimeter (ScanPol) designed for remote sensing studies of the global distribution of aerosol and cloud properties (such as particle size, morphology, and composition) in the terrestrial atmosphere by polarimetric and spectrophotometric measurements of the scattered sunlight in a wide range of wavelengths and viewing directions from which a scene location is observed. ScanPol is accompanied by multispectral wide-angle imager-polarimeter (MSIP) that serves to collect information on cloud conditions and Earth's surface image. Various components of the polarimeter ScanPol have been prototyped, including the opto-mechanical and electronic assemblies and the scanning mirror controller. Preliminary synthetic data simulations for the retrieval of aerosol parameters over land surfaces have been performed using the Generalized Retrieval of Aerosol and Surface Properties (GRASP) algorithm. Methods for the validation of satellite data using ground-based observations of aerosol properties are also discussed. We assume that designing, building, and launching into orbit a multi

  14. The contribution of aerosol hygroscopic growth to the modeled aerosol radiative effect

    Science.gov (United States)

    Kokkola, Harri; Kühn, Thomas; Kirkevåg, Alf; Romakkaniemi, Sami; Arola, Antti

    2016-04-01

    The hygroscopic growth of atmospheric aerosols can have a significant effect on the direct radiative effect of atmospheric aerosol. However, there are significant uncertainties concerning how much of the radiative forcing is due to different chemical compounds, especially water. For example, modeled optical depth of water in global aerosol-climate models varies by more than a factor of two. These differences can be attributed to differences in modeled 1) hygroscopicity, 2) ambient relative humidity, and/or 3) aerosol size distribution. In this study, we investigate which of these above-mentioned factors cause the largest variability in the modeled optical depth of water. In order to do this, we have developed a tool that calculates aerosol extinction using interchangeable global 3D data of aerosol composition, relative humidity, and aerosol size distribution fields. This data is obtained from models that have taken part in the open international initiative AeroCom (Aerosol Comparisons between Observations and Models). In addition, we use global 3D data for relative humidity from the Atmospheric Infrared Sounder (AIRS) flying on board NASA's Aqua satellite and the National Centers for Environmental Prediction (NCEP) reanalysis data. These observations are used to evaluate the modeled relative humidity fields. In the first stage of the study, we made a detailed investigation using the aerosol-chemistry-climate model ECHAM-HAMMOZ in which most of the aerosol optical depth is caused by water. Our results show that the model significantly overestimates the relative humidity over the oceans while over land, the overestimation is lower or it is underestimated. Since this overestimation occurs over the oceans, the water optical depth is amplified as the hygroscopic growth is very sensitive to changes in high relative humidities. Over land, error in modeled relative humidity is unlikely to cause significant errors in water optical depth as relative humidities are generally

  15. New Satellite Project Aerosol-UA: Remote Sensing of Aerosols in the Terrestrial Atmosphere

    Science.gov (United States)

    Milinevsky, G.; Yatskiv, Ya.; Degtyaryov, O.; Syniavskyi, I.; Mishchenko, Michael I.; Rosenbush, V.; Ivanov, Yu.; Makarov, A.; Bovchaliuk, A.; Danylevsky, V.; Sosonkin, M.; Moskalov, S.; Bovchaliuk, V; Lukenyuk, A.; Shymkiv, A.

    2016-01-01

    We discuss the development of the Ukrainian space project Aerosol-UA which has the following three main objectives: (1) to monitor the spatial distribution of key characteristics of terrestrial tropospheric and stratospheric aerosols; (2) to provide a comprehensive observational database enabling accurate quantitative estimates of the aerosol contribution to the energy budget of the climate system; and (3) quantify the contribution of anthropogenic aerosols to climate and ecological processes. The remote sensing concept of the project is based on precise orbital measurements of the intensity and polarization of sunlight scattered by the atmosphere and the surface with a scanning polarimeter accompanied by a wide-angle multispectral imager-polarimeter. Preparations have already been made for the development of the instrument suite for the Aerosol-UA project, in particular, of the multi-channel scanning polarimeter (ScanPol) designed for remote sensing studies of the global distribution of aerosol and cloud properties (such as particle size, morphology, and composition) in the terrestrial atmosphere by polarimetric and spectrophotometric measurements of the scattered sunlight in a wide range of wavelengths and viewing directions from which a scene location is observed. ScanPol is accompanied by multispectral wide-angle imager-polarimeter (MSIP) that serves to collect information on cloud conditions and Earths surface image. Various components of the polarimeter ScanPol have been prototyped, including the opto-mechanical and electronic assemblies and the scanning mirror controller. Preliminary synthetic data simulations for the retrieval of aerosol parameters over land surfaces have been performed using the Generalized Retrieval of Aerosol and Surface Properties (GRASP) algorithm. Methods for the validation of satellite data using ground-based observations of aerosol properties are also discussed. We assume that designing, building, and launching into orbit a multi

  16. Modeling the Relationships Between Aerosol Properties and the Direct and Indirect Effects of Aerosols on Climate

    Science.gov (United States)

    Toon, Owen B.

    1994-01-01

    Aerosols may affect climate directly by scattering and absorbing visible and infrared energy, They may also affect climate indirectly by modifying the properties of clouds through microphysical processes, and by altering abundances of radiatively important gases through heterogeneous chemistry. Researchers understand which aerosol properties control the direct effect of aerosols on the radiation budget. Unfortunately, despite an abundance of data on certain types of aerosols, much work remains to be done to determine the values of these properties. For instance we have little idea about the global distribution, seasonal variation, or interannual variability of the aerosol optical depth. Also we do not know the visible light absorption properties of tropical aerosols which may contain much debris from slash and burn agriculture. A positive correlation between aerosol concentrations and albedos of marine stratus clouds is observed, and the causative microphysics is understood. However, models suggest that it is difficult to produce new particles in the marine boundary layer. Some modelers have suggested that the particles in the marine boundary layer may originate in the free troposphere and be transported into the boundary layer. Others argue that the aerosols are created in the marine boundary layer. There are no data linking aerosol concentration and cirrus cloud albedo, and models suggest cirrus properties may not be very sensitive to aerosol abundance. There is clear evidence of a radiatively significant change in the global lower stratospheric ozone abundance during the past few decades. These changes are caused by heterogeneous chemical reactions occurring on the surfaces of particles. The rates of these reactions depend upon the chemical composition of the particles. Although rapid advances in understanding heterogeneous chemistry have been made, much remains to be done.

  17. Development of a cavity enhanced aerosol albedometer

    Directory of Open Access Journals (Sweden)

    W. Zhao

    2014-03-01

    Full Text Available We report on the development of a cavity enhanced aerosol single scattering albedometer incorporating incoherent broad-band cavity-enhanced spectroscopy (IBBCEAS approach and an integrating sphere (IS for simultaneous in situ measurements of aerosol scattering and extinction coefficients in the exact same sample volume. The cavity enhanced albedometer employed a blue light-emitting diode (LED based IBBCEAS approach for the measurement of wavelength-resolved aerosol optical extinction over the spectral range of 445–480 nm. An integrating sphere nephelometer coupled to the IBBCEAS setup was used for the measurement of aerosol scattering. The scattering signal was measured with a single channel photomultiplier tube (PMT, providing an integrated value over a narrow bandwidth (FWHM ~ 9 nm in the spectral region of 465–474 nm. A scattering coefficient at a wavelength of 470 nm was deduced as an averaged scattering value and used for data analysis and instrumental performance comparison. Performance evaluation of the albedometer was carried out using laboratory-generated particles and ambient aerosol. The scattering and extinction measurements of monodisperse polystyrene latex (PSL spheres generated in laboratory proved excellent correlation between two channels of the albedometer. The retrieved refractive index (RI from the measured scattering and extinction efficiencies agreed well with the values reported in previously published papers. Aerosol light scattering and extinction coefficients, single scattering albedo (SSA and NO2 concentrations in an ambient sample were directly and simultaneously measured using the developed albedometer. The developed instrument was validated via an intercomparison of the measured aerosol scattering coefficient and NO2 trace concentration against a TSI 3563 integrating nephelometer and a chemiluminescence detector, respectively.

  18. Beijing aerosol: Atmospheric interactions and new trends

    International Nuclear Information System (INIS)

    Beijing aerosols are scrutinized as a case study for atmospheric interactions in a complex multi-source situation. For the first time, fine (≤ 2 μm) and coarse (≥ 2 μm) aerosols were continuously collected during a time period (20 months) long enough to capture seasonal trends of sources and interactions. Weekly samples were obtained from January 2003 to August 2004 downtown and during 9 months at two peri-urban sites. Aerosol samples were chemically characterized (black carbon (BC), organic carbon (OC), and major ions) and dust was obtained from mass closure. Concentration data were smoothed and boundary layer height (BLH) corrected in order to better identify sources and processes. All yearlong, the coarse aerosol is dominated by dust (75%) whereas the fine mode is dominated (46%) by carbonaceous particles. Photochemistry is an intense driving force for secondary aerosol formation including secondary organic aerosol (SOA). Dust particles present a reactive surface for secondary aerosol formation from the intense anthropogenic pool of acidic gaseous precursors (SO2, HNO3, and volatile organic compounds (VOCs)). These interactions favor the formation of a very significant coarse fraction for SO4, NO3, and POM, a feature almost never encountered in developed countries. Surprisingly too is the presence of fine NH4NO3 in summer. A new result is also that the winter 'heating season' appears at present of minor importance with, however, a significant component from domestic heating as traced by BC/OC. In the future, traffic is likely to dominate downtown anthropogenic emissions. Year-to-year variability in meteorological conditions is likely to influence inputs from arid regions and from regional industrial and biomass burning sources. (authors)

  19. Retrieving aerosol in a cloudy environment: aerosol product availability as a function of spatial resolution

    Directory of Open Access Journals (Sweden)

    L. A. Remer

    2012-07-01

    Full Text Available The challenge of using satellite observations to retrieve aerosol properties in a cloudy environment is to prevent contamination of the aerosol signal from clouds, while maintaining sufficient aerosol product yield to satisfy specific applications. We investigate aerosol retrieval availability at different instrument pixel resolutions using the standard MODIS aerosol cloud mask applied to MODIS data and supplemented with a new GOES-R cloud mask applied to GOES data for a domain covering North America and surrounding oceans. Aerosol product availability is not the same as the cloud free fraction and takes into account the techniques used in the MODIS algorithm to avoid clouds, reduce noise and maintain sufficient numbers of aerosol retrievals. The inherent spatial resolution of each instrument, 0.5×0.5 km for MODIS and 1×1 km for GOES, is systematically degraded to 1×1, 2×2, 1×4, 4×4 and 8×8 km resolutions and then analyzed as to how that degradation would affect the availability of an aerosol retrieval, assuming an aerosol product resolution at 8×8 km. The analysis is repeated, separately, for near-nadir pixels and those at larger view angles to investigate the effect of pixel growth at oblique angles on aerosol retrieval availability. The results show that as nominal pixel size increases, availability decreases until at 8×8 km 70% to 85% of the retrievals available at 0.5 km, nadir, have been lost. The effect at oblique angles is to further decrease availability over land but increase availability over ocean, because sun glint is found at near-nadir view angles. Finer resolution sensors (i.e., 1×1, 2×2 or even 1×4 km will retrieve aerosols in partly cloudy scenes significantly more often than sensors with nadir views of 4×4 km or coarser. Large differences in the results of the two cloud masks designed for MODIS aerosol and GOES cloud products strongly reinforce that cloud masks must be developed with specific purposes in mind and

  20. Aromatic Structure in Simulates Titan Aerosol

    Science.gov (United States)

    Trainer, Melissa G.; Loeffler, M. J.; Anderson, C. M.; Hudson, R. L.; Samuelson, R. E.; Moore, M. A.

    2011-01-01

    Observations of Titan by the Cassini Composite Infrared Spectrometer (CIRS) between 560 and 20 per centimeter (approximately 18 to 500 micrometers) have been used to infer the vertical variations of Titan's ice abundances, as well as those of the aerosol from the surface to an altitude of 300 km [1]. The aerosol has a broad emission feature centered approximately at 140 per centimeter (71 micrometers). As seen in Figure 1, this feature cannot be reproduced using currently available optical constants from laboratory-generated Titan aerosol analogs [2]. The far-IR is uniquely qualified for investigating low-energy vibrational motions within the lattice structures of COITIDlex aerosol. The feature observed by CIRS is broad, and does not likely arise from individual molecules, but rather is representative of the skeletal movements of macromolecules. Since Cassini's arrival at Titan, benzene (C6H6) has been detected in the atmosphere at ppm levels as well as ions that may be polycyclic aromatic hydrocarbons (PAHs) [3]. We speculate that the feature may be a blended composite that can be identified with low-energy vibrations of two-dimensional lattice structures of large molecules, such as PAHs or nitrogenated aromatics. Such structures do not dominate the composition of analog materials generated from CH4 and N2 irradiation. We are performing studies forming aerosol analog via UV irradiation of aromatic precursors - specifically C6H6 - to understand how the unique chemical architecture of the products will influence the observable aerosol characteristics. The optical and chemical properties of the aromatic analog will be compared to those formed from CH4/N2 mixtures, with a focus on the as-yet unidentified far-IR absorbance feature. Preliminary results indicate that the photochemically-formed aromatic aerosol has distinct chemical composition, and may incorporate nitrogen either into the ring structure or adjoined chemical groups. These compositional differences are

  1. Intercomparison of aerosol instruments: number concentration

    International Nuclear Information System (INIS)

    An intercomparison of aerosol instruments conducted February 23-27, 1981, at the Environmental Measurements Laboratory (EML) focused on five instruments: the Pollak and TSI condensation nucleus counters; the Active Scattering Aerosol Spectrometer (ASAS-X); and two aerosol electrometers. Test aerosols of sodium chloride and ammonium fluorescein generated by nebulization/electrostatic classification were used to obtain 195 lines of comparison data. Concentrations measured by the ASAS-X and the TSI aerosol electrometer averaged respectively 1.388 and 1.581 times that measured by the Pollak. These ratios were very stable during the week and there was little effect of particle size or material. Most other comparisons were equally stable. However, a review of past work at EML and elsewhere led to the disturbing conclusion that these ratios may change from year to year, or from season to season. A filter sample was taken from microscopy, concurrent with readings from the ASAS-X and the TSI condensation nucleus counters. In this sample, the two instruments differed by 20%. Within its 20% uncertainty, the filter result matched both the TSI and ASAS-X readings

  2. Microphysical Characterization of Aerosol Signatures over Greece

    Directory of Open Access Journals (Sweden)

    Akshath Sharma

    2016-07-01

    Full Text Available A detailed microphysical characterization is presented for aerosol spectra over three major areas over Greece, namely- the Area West of Crete (AWC, the Greater Thessaloniki area (GTA and the Greater Athens Area (GAA based on measurements made by Varotsos (2005. Aerosol size distributions along with cloud droplet concentrations were gathered from data collected from the Forward Scattering Spectrometer Probe (FSSP-300 and Passive Cavity Aerosol Spectrometer Probe (PCASP-100X flown on a Falcon aircraft over Greece (Varotsos, 2005. However, the microphysical and dynamical characterisation of the observations were left largely unexplored (for this later paper, particularly with regard to their growth and activation into cloud condensation nuclei. A suite of models involving Large Eddy Simulations and an Adiabatic Parcel Model were used to achieve this. The UK Met Office large eddy model (LEM reveals that mild to moderate updraughts in the range of 0.5 ms-1 to 2 ms-1 were present over Athens during June 1997, over the regions containing the aerosol bands. The sophisticated parcel model was then been applied to this data to study the growth of aerosol in the updraughts present and further, to explore the possibility of rainfall. It is found that the grown droplets have radii spanning a range of 6 μm to 100 μm indicating a hundredfold increase over initial size and the region spanning height from 2700 to 3000 meters contains precipitable water.

  3. Monitoring biological aerosols using UV fluorescence

    Science.gov (United States)

    Eversole, Jay D.; Roselle, Dominick; Seaver, Mark E.

    1999-01-01

    An apparatus has been designed and constructed to continuously monitor the number density, size, and fluorescent emission of ambient aerosol particles. The application of fluorescence to biological particles suspended in the atmosphere requires laser excitation in the UV spectral region. In this study, a Nd:YAG laser is quadrupled to provide a 266 nm wavelength to excite emission from single micrometer-sized particles in air. Fluorescent emission is used to continuously identify aerosol particles of biological origin. For calibration, biological samples of Bacillus subtilis spores and vegetative cells, Esherichia coli, Bacillus thuringiensis and Erwinia herbicola vegetative cells were prepared as suspensions in water and nebulized to produce aerosols. Detection of single aerosol particles, provides elastic scattering response as well as fluorescent emission in two spectral bands simultaneously. Our efforts have focuses on empirical characterization of the emission and scattering characteristics of various bacterial samples to determine the feasibility of optical discrimination between different cell types. Preliminary spectroscopic evidence suggest that different samples can be distinguished as separate bio-aerosol groups. In addition to controlled sample results, we will also discuss the most recent result on the effectiveness of detection outdoor releases and variations in environmental backgrounds.

  4. Spectral Absorption Properties of Atmospheric Aerosols

    Science.gov (United States)

    Bergstrom, R. W.; Pilewskie, P.; Russell, P. B.; Redemann, J.; Bond, T. C.; Quinn, P. K.; Sierau, B.

    2007-01-01

    We have determined the solar spectral absorption optical depth of atmospheric aerosols for specific case studies during several field programs (three cases have been reported previously; two are new results). We combined airborne measurements of the solar net radiant flux density and the aerosol optical depth with a detailed radiative transfer model for all but one of the cases. The field programs (SAFARI 2000, ACE Asia, PRIDE, TARFOX, INTEX-A) contained aerosols representing the major absorbing aerosol types: pollution, biomass burning, desert dust and mixtures. In all cases the spectral absorption optical depth decreases with wavelength and can be approximated with a power-law wavelength dependence (Absorption Angstrom Exponent or AAE). We compare our results with other recent spectral absorption measurements and attempt to briefly summarize the state of knowledge of aerosol absorption spectra in the atmosphere. We discuss the limitations in using the AAE for calculating the solar absorption. We also discuss the resulting spectral single scattering albedo for these cases.

  5. Atmospheric Aerosol Analysis using Lightweight Mini GC Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The major components of manmade aerosols are created by the burning of coal and oil. These aerosols are recognized to have a significant climatic impact through...

  6. MISR Level 2 FIRSTLOOK Aerosol parameters V001

    Data.gov (United States)

    National Aeronautics and Space Administration — This is the Level 2 FIRSTLOOK Aerosol Product. It contains Aerosol optical depth and particle type, with associated atmospheric data, produced using ancillary...

  7. Volatility of Nuclei Mode Arctic Aerosol Particles during Summer

    Czech Academy of Sciences Publication Activity Database

    Biskos, J.G.; Vratolis, S.; Ondráček, Jakub; Karanasioy, A.A.; Eleftheriadis, K.

    -: -, 2009, T160A13. [European Aerosol Conference 2009. Karlsruhe (DE), 06.09.2009-11.09.2009] Institutional research plan: CEZ:AV0Z40720504 Keywords : arctic aerosol * nucleation mode * volatility Subject RIV: CF - Physical ; Theoretical Chemistry

  8. VERTICAL DISTRIBUTION OF ATMOSPHERIC AEROSOL CONCENTRATION AT XIANGHE

    Institute of Scientific and Technical Information of China (English)

    Li Xu; Guangyu Shi; Jun Zhou; Yasunobu Iwasaka

    2004-01-01

    This paper summarizes atmospheric aerosol concentrations of 5 stratospheric balloon soundings during the period from 1984 to 1994. Aerosol-rich layers in the troposphere were detected and the causes were analyzed. The main results are as follows: (1) the vertical distribution of the atmospheric aerosol is affected by atmospheric dynamic processes, humidity, etc.; (2) the tropospheric column concentrations of aerosol were 72.2×105, 20.2×105, 20.7×105 and 34.4×105 cm-2 and occupying 81%, 61% and 60% of the 0-to-30 km aerosol column, on Aug. 23, 1984, Aug. 22, 1993,Sept. 12, 1993 and Sept. 15, 1994, respectively; (3) the effect of volcano eruption was still evident in the aerosol profiles,28 and 27 months after the El Chichon and Pinatubo eruption; (4) the aerosol concentration in the troposphere did not decrease at all heights as atmospheric aerosol model.

  9. MISR Level 3 Global Joint Aerosol monthly product V001

    Data.gov (United States)

    National Aeronautics and Space Administration — MISR Level 3 Global Joint Aerosol monthly product (Suggested Usage: This file contains MISR Level 3 Global Joint Aerosol monthly product, binned at 5 degree...

  10. Characterisation of high dose aerosols from dry powder inhalers

    NARCIS (Netherlands)

    Grasmeijer, Floris; Hagedoorn, Paul; Frijlink, Henderik W; de Boer, Anne H

    2012-01-01

    Developments in high dose dry powder aerosol delivery will increasingly challenge the applicability of currently used aerosol characterisation techniques. With cascade impaction analysis bounce effects can negatively influence stage collection efficiency, especially with increasing impactor loads. I

  11. Atmospheric Aerosol Analysis using Lightweight Mini GC Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The major components of manmade aerosols are created by the burning of coal and oil. Aerosols are recognized to significantly impact the climate through their...

  12. The polarity protein Par6 is coupled to the microtubule network during molluscan early embryogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Homma, Taihei [Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Shimizu, Miho [Kuroda Chiromorphology Team, ERATO-SORST, JST, Komaba, Meguro-ku, Tokyo 153-8902 (Japan); Kuroda, Reiko, E-mail: ckuroda@mail.ecc.u-tokyo.ac.jp [Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Kuroda Chiromorphology Team, ERATO-SORST, JST, Komaba, Meguro-ku, Tokyo 153-8902 (Japan); Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902 (Japan)

    2011-01-07

    Research highlights: {yields} The cDNAs encoding Par6 and aPKC homologues were cloned from the snail Lymnaea stagnalis. {yields} L. stagnalis Par6 directly interacts with tubulin and microtubules and localizes to the microtubule cytoskeleton during the early embryogenesis. {yields} Identical sequence and localization of LsPar6 for the dextral and the sinistral snails exclude the possibility of the gene being the primary determinant of body handedness. -- Abstract: Cell polarity, which directs the orientation of asymmetric cell division and segregation of fate determinants, is a fundamental feature of development and differentiation. Regulators of polarity have been extensively studied, and the critical importance of the Par (partitioning-defective) complex as the polarity machinery is now recognized in a wide range of eukaryotic systems. The Par polarity module is evolutionarily conserved, but its mechanism and cooperating factors vary among different systems. Here we describe the cloning and characterization of a pond snail Lymnaea stagnalis homologue of partitioning-defective 6 (Lspar6). The protein product LsPar6 shows high affinity for microtubules and localizes to the mitotic apparatus during embryonic cell division. In vitro assays revealed direct binding of LsPar6 to tubulin and microtubules, which is the first evidence of the direct interaction between the two proteins. The interaction is mediated by two distinct regions of LsPar6 both located in the N-terminal half. Atypical PKC, a functional partner of Par6, was also found to localize to the mitotic spindle. These results suggest that the L. stagnalis Par complex employs the microtubule network in cell polarity processes during the early embryogenesis. Identical sequence and localization of LsPar6 for the dextral and the sinistral snails exclude the possibility of the gene being the primary determinant of handedness.

  13. A characterization of Arctic aerosols on the basis of aerosol optical depth and black carbon measurements

    Directory of Open Access Journals (Sweden)

    R. S. Stone

    2014-06-01

    Full Text Available Abstract Aerosols, transported from distant source regions, influence the Arctic surface radiation budget. When deposited on snow and ice, carbonaceous particles can reduce the surface albedo, which accelerates melting, leading to a temperature-albedo feedback that amplifies Arctic warming. Black carbon (BC, in particular, has been implicated as a major warming agent at high latitudes. BC and co-emitted aerosols in the atmosphere, however, attenuate sunlight and radiatively cool the surface. Warming by soot deposition and cooling by atmospheric aerosols are referred to as “darkening” and “dimming” effects, respectively. In this study, climatologies of spectral aerosol optical depth AOD (2001–2011 and Equivalent BC (EBC (1989–2011 from three Arctic observatories and from a number of aircraft campaigns are used to characterize Arctic aerosols. Since the 1980s, concentrations of BC in the Arctic have decreased by more than 50% at ground stations where in situ observations are made. AOD has increased slightly during the past decade, with variations attributed to changing emission inventories and source strengths of natural aerosols, including biomass smoke and volcanic aerosol, further influenced by deposition rates and airflow patterns.

  14. Multicomponent aerosol dynamics model UHMA: model development and validation

    OpenAIRE

    Korhonen, H.; Lehtinen, K. E. J.; Kulmala, M.

    2004-01-01

    A size-segregated aerosol dynamics model UHMA (University of Helsinki Multicomponent Aerosol model) was developed for studies of multicomponent tropospheric aerosol particles. The model includes major aerosol microphysical processes in the atmosphere with a focus on new particle formation and growth; thus it incorporates particle coagulation and multicomponent condensation, applying a revised treatment of condensation flux onto free molecular regime particles and the activation of nanosi...

  15. Effect of Aerosol and Ocean Representation on Simulated Climate Responses

    Science.gov (United States)

    Dallafior, Tanja; Folini, Doris; Knutti, Reto; Wild, Martin

    2016-04-01

    It is still debated to what extent anthropogenic aerosols shaped 20th century surface temperatures, especially sea surface temperatures (SSTs), through alteration of surface solar radiation (SSR). SSTs, in turn, are crucial in the context of atmospheric circulation and ocean heat uptake. Uncertainty considering anthropogenic aerosol forcing thus translates into uncertainty regarding ocean heat uptake and, ultimately, climate responses towards anthropogenic influences. We use the global climate model ECHAM to analyse the 20th century climate response towards either anthropogenic aerosols or well-mixed greenhouse gases or both with different representations of ocean and aerosols: atmosphere-only with prescribed SSTs and interactive aerosols; mixed-layer ocean and interactive or prescribed aerosols; fully coupled with prescribed aerosols. For interactive aerosols we use the Hamburg Aerosol Module (HAM). Our results suggest that up to 15% of global ocean surfaces undergo an SSR reduction of at least -4W/m² in the year 2000, due to anthropogenic aerosols. The area affected depends on how aerosols are represented and whether clear sky or all sky SSR is considered. In MLO equilibria with interactive aerosols, anthropogenic aerosols clearly shape surface temperature response patterns. This is to a lesser degree the case for the transient fully coupled case. Additivity of global mean temperature responses towards single forcings - an assumption often made in the literature - is not fulfilled for the MLO experiments, but for the fully coupled experiments. While some of these differences can be attributed to the differing ocean representation, it is implied that differing aerosol representation may play an even more relevant role. Thus, our results corroborate not only the relevance of anthropogenic aerosols for surface temperature responses, but also highlight the relevance of choice of aerosol representation.

  16. Global modeling of organic aerosol: the importance of reactive nitrogen

    OpenAIRE

    H. O. T. Pye; A. W. H. Chan; Barkley, M. P.; Seinfeld, J. H.

    2010-01-01

    Reactive nitrogen compounds, specifically NOx and NO3, likely influence global organic aerosol levels. To assess these interactions, GEOS-Chem, a chemical transport model, is updated to include improved biogenic emissions (following MEGAN v2.1/2.04), a new organic aerosol tracer lumping scheme, aerosol from nitrate radical (NO3) oxidation of isoprene, and NOx-dependent terpene aerosol yields. As a resu...

  17. La libération par Tupperware ?

    OpenAIRE

    Achin, Catherine; Naudier, Delphine

    2009-01-01

    Au cours des années 1970, le développement de la vente directe à domicile a donné lieu à la formation de cercles de sociabilité entre femmes dans le cadre des réunions Tupperware. Ces rencontres ont contribué à diffuser par capillarité nombre d’idées et pratiques féministes. Elles n’ont pas été sans incidence sur le déroulement de certaines trajectoires de femmes des classes moyennes et populaires. Le partage d’expériences de la soumission féminine, conjugale, et la confrontation aux modèles ...

  18. IMPROVEMENT OF PRODUCTION PLANNING IN COMPANY PARS KOMPONENTY

    Directory of Open Access Journals (Sweden)

    René Klega

    2014-03-01

    Full Text Available The article analyzes the current status of production planning in company Pars Komponenty s.r.o., proposes a new method of planning based on application of the principle of MRP. It is a discrete type of production with high complexity of BOM and MTO (Make-to-Order and ETO (Engineering-to-Order from the point of decoupling point. The original planning system plans according to production capacity backward without collisions, but for a given type of production does not work in practice. Planning system was analyzed and the main problems were identified, which were high work in progress and material stocks. This article target is to propose a new planining system based on the inclusion of time reserves of purchased material items. New planning system was tested in practise with benefit in reducing both the material inventory and work in progress.

  19. Le succès par l’image ?

    OpenAIRE

    Chermette, Myriam

    2008-01-01

    Fig. 1. Paris-Soir, 3 septembre 1933, n°3620, page 1 (détail), coll. ACRPP. L’image fait-elle vendre ? La question n’est pas neuve, a été maintes fois posée et la réponse par l’affirmative paraît aujourd’hui évidente si l’on s’en tient au flux d’images que nous avons quotidiennement sous les yeux. Le monde de la presse, particulièrement, lui accorde une légitimité incontestée, les nouvelles formules laissant davantage de place à l’iconographie. Cettesituation n’est pas le résultat d’un long c...

  20. Etude d’un plasma produit par ablation laser.

    OpenAIRE

    DJAOUANI, Nedjwa

    2014-01-01

    L’ablation laser est une technique d’enlèvement de matière de la surface d’un solide ou d’un liquide par l’irradiation laser, largement utilisée aujourd’hui. Elle s’est développée depuis l’époque de l’invention des lasers (1960). Très rapidement, le processus d’ablation laser est devenu le sujet d’intérêt de beaucoup de scientifiques. Même si la réalisation d’ablation laser est assez simple, ce phénomène est très complexe ce qui confirme le fait que 50 ans après sa découverte i...

  1. Simulation numérique du soudage par frottement malaxage

    OpenAIRE

    Guerdoux, Simon

    2007-01-01

    Ce travail présente le développement d'un outil numérique. Une formulation arbitrairement lagrangienne-eulérienne (ALE) est implémentée dans le logiciel 3D éléments finis FORGE3® pour simuler les différentes étapes du procédé de soudage par frottement malaxage (FSW). Une méthode découplée est utilisée : a) les champs de vitesses, pressions et températures du matériau sont calculés, b) la vitesse de maillage est calculée à partir de l'évolution des frontières du domaine et d'un critère de raff...

  2. Whole-Body Nanoparticle Aerosol Inhalation Exposures

    Science.gov (United States)

    Yi, Jinghai; Chen, Bean T.; Schwegler-Berry, Diane; Frazer, Dave; Castranova, Vince; McBride, Carroll; Knuckles, Travis L.; Stapleton, Phoebe A.; Minarchick, Valerie C.; Nurkiewicz, Timothy R.

    2013-01-01

    Inhalation is the most likely exposure route for individuals working with aerosolizable engineered nano-materials (ENM). To properly perform nanoparticle inhalation toxicology studies, the aerosols in a chamber housing the experimental animals must have: 1) a steady concentration maintained at a desired level for the entire exposure period; 2) a homogenous composition free of contaminants; and 3) a stable size distribution with a geometric mean diameter < 200 nm and a geometric standard deviation σg < 2.5 5. The generation of aerosols containing nanoparticles is quite challenging because nanoparticles easily agglomerate. This is largely due to very strong inter-particle forces and the formation of large fractal structures in tens or hundreds of microns in size 6, which are difficult to be broken up. Several common aerosol generators, including nebulizers, fluidized beds, Venturi aspirators and the Wright dust feed, were tested; however, none were able to produce nanoparticle aerosols which satisfy all criteria 5. A whole-body nanoparticle aerosol inhalation exposure system was fabricated, validated and utilized for nano-TiO2 inhalation toxicology studies. Critical components: 1) novel nano-TiO2 aerosol generator; 2) 0.5 m3 whole-body inhalation exposure chamber; and 3) monitor and control system. Nano-TiO2 aerosols generated from bulk dry nano-TiO2 powders (primary diameter of 21 nm, bulk density of 3.8 g/cm3) were delivered into the exposure chamber at a flow rate of 90 LPM (10.8 air changes/hr). Particle size distribution and mass concentration profiles were measured continuously with a scanning mobility particle sizer (SMPS), and an electric low pressure impactor (ELPI). The aerosol mass concentration (C) was verified gravimetrically (mg/m3). The mass (M) of the collected particles was determined as M = (Mpost-Mpre), where Mpreand Mpost are masses of the filter before and after sampling (mg). The mass concentration was calculated as C = M/(Q*t), where Q is

  3. Phase transformation and growth of hygroscopic aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Tang, I.N.

    1999-11-01

    Ambient aerosols play an important role in many atmospheric processes affecting air quality, visibility degradation, and climatic changes as well. Both natural and anthropogenic sources contribute to the formation of ambient aerosols, which are composed mostly of sulfates, nitrates, and chlorides in either pure or mixed forms. These inorganic salt aerosols are hygroscopic by nature and exhibit the properties of deliquescence and efflorescence in humid air. For pure inorganic salt particles with diameter larger than 0.1 micron, the phase transformation from a solid particle to a saline droplet occurs only when the relative humidity in the surrounding atmosphere reaches a certain critical level corresponding to the water activity of the saturated solution. The droplet size or mass in equilibrium with relative humidity can be calculated in a straightforward manner from thermodynamic considerations. For aqueous droplets 0.1 micron or smaller, the surface curvature effect on vapor pressure becomes important and the Kelvin equation must be used.

  4. Washout and dry deposition of atmospheric aerosols

    International Nuclear Information System (INIS)

    The deposition velocities onto different rough surfaces and the washout coefficients of simulated rain droplets for submicron aerosols were studied in a wind channel. The influence of particle size and electric charge upon the collection efficiencies of simulated rain droplets was measured. The deposition velocity of the particles was determined as a function of aerosol size, wind velocity and roughness of the surface. The experiments were carried out with monodisperse, radioactive particles with sizes which were varied from 0.03 and 5 μm. Using the measured values, the activity flux of the long lived radon decay product (RaD), the mass flux of the atmospheric aerosol and the activity flux near a stack of a nuclear power plant onto the ground surface were calculated considering washout, rainout and dry deposition in the atmosphere. (author)

  5. Accelerator based techniques for aerosol analysis

    International Nuclear Information System (INIS)

    At the 3 MV Tandetron accelerator of the LABEC laboratory of INFN (Florence, Italy) an external beam facility is fully dedicated to PIXE-PIGE measurements of elemental composition of atmospheric aerosols. Examples regarding recent monitoring campaigns, performed in urban and remote areas, both on a daily basis and with high time resolution, as well as with size selection, will be presented. It will be evidenced how PIXE can provide unique information in aerosol studies or can play a complementary role to traditional chemical analysis. Finally a short presentation of 14C analysis of the atmospheric aerosol by Accelerator Mass Spectrometry (AMS) for the evaluation of the contributions from either fossil fuel combustion or modern sources (wood burning, biogenic activity) will be given. (author)

  6. Change in global aerosol composition since preindustrial times

    NARCIS (Netherlands)

    Tsigaridis, K.; Krol, M.C.; Dentener, F.; Balkanski, Y.; Lathiere, J.; Metzger, S.; Hauglustaine, D.; Kanakidou, M.

    2006-01-01

    To elucidate human induced changes of aerosol load and composition in the atmosphere, a coupled aerosol and gas-phase chemistry transport model of the troposphere and lower stratosphere has been used. The present 3-D modeling study focuses on aerosol chemical composition change since preindustrial t

  7. Aerosol retrieval from OMI: Applications to the amazon bassin

    NARCIS (Netherlands)

    Curier, R.L.; Veefkind, J.P.; Veilhmann, B.; Braak, R.; Torres, O.; Leeuw, G.de

    2007-01-01

    We present the aerosol optical depth retrieved from OMI measurements using the multi-wavelengthm algorithm for two different environments: over Western Europe where the aerosols are weakly absorbing and over the Amazon basin where aerosol optical properties are governed by biomass burning. The resul

  8. Improvements in the Advanced Navy Aerosol Model (ANAM)

    NARCIS (Netherlands)

    Eijk, A.M.J. van; Merritt, D.L.

    2006-01-01

    The Navy Aerosol Model (NAM) is widely used as an engineering tool to provide a quick estimate of the aerosol extinction in the marine environment. Since its introduction, several shortcomings of NAM have been identified that are being addressed by the development of the Advanced Navy Aerosol Model

  9. Determination of atmospheric aerosol properties over land using satellite measurements

    NARCIS (Netherlands)

    Kokhanovsky, A.A.; Leeuw, G. de

    2009-01-01

    Mostly, aerosol properties are poorly understood because the aerosol properties are very sparse. The first workshop on the determination of atmospheric aerosol properties over land using satellite measurements is convened in Bremen, Germany. In this workshop, the topics of discussions included a var

  10. METHODS OF CALCULATINAG LUNG DELIVERY AND DEPOSITION OF AEROSOL PARTICLES

    Science.gov (United States)

    Lung deposition of aerosol is measured by a variety of methods. Total lung deposition can be measured by monitoring inhaled and exhaled aerosols in situ by laser photometry or by collecting the aerosols on filters. The measurements can be performed accurately for stable monod...

  11. THE EFFECT OF AEROSOLIZATION ON SUBSEQUENT BACTERIAL SURVIVAL

    Science.gov (United States)

    To determine whether aerosolization could impair baterial survival, Pseudomonas syringae and Erwinia herbicola were aerosolized in a greenhouse, the aerosol was sampled at various distances from the site of release by using all-glass impingers, and bacterial survival was followed...

  12. Size Dependence of Incorporation of Gas Molecules into Aerosol Nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Levdansky, V.V.; Smolík, Jiří; Ždímal, Vladimír; Moravec, Pavel

    Prague : Czech Aerosol Society , 2013, C027. ISBN N. [European Aerosol Conference (EAC 2013). Prague (CZ), 01.09.2013-06.09.2013] R&D Projects: GA AV ČR IAA200760905 Institutional support: RVO:67985858 Keywords : aerosol * nanoparticles * size effect Subject RIV: CF - Physical ; Theoretical Chemistry http://eac2013.cz/index.php

  13. Global modeling of organic aerosol: the importance of reactive nitrogen

    Science.gov (United States)

    Pye, H. O. T.; Chan, A. W. H.; Barkley, M. P.; Seinfeld, J. H.

    2010-09-01

    Reactive nitrogen compounds, specifically NOx and NO3, likely influence global organic aerosol levels. To assess these interactions, GEOS-Chem, a chemical transport model, is updated to include improved biogenic emissions (following MEGAN v2.1/2.04), a new organic aerosol tracer lumping scheme, aerosol from nitrate radical (NO3) oxidation of isoprene, and NOx-dependent terpene aerosol yields. As a result of significant nighttime terpene emissions, fast reaction of monoterpenes with the nitrate radical, and relatively high aerosol yields from NO3 oxidation, biogenic hydrocarbon-NO3 reactions are expected to be a major contributor to surface level aerosol concentrations in anthropogenically influenced areas such as the United States. By including aerosol from nitrate radical oxidation in GEOS-Chem, terpene aerosol approximately doubles and isoprene aerosol is enhanced by 30 to 40% in the Southeast United States. In terms of the global budget of organic aerosol, however, aerosol from nitrate radical oxidation is somewhat minor (slightly more than 3 Tg/yr) due to the relatively high volatility of organic-NO3 oxidation products. Globally, 69 to 88 Tg/yr of organic aerosol is predicted to be produced annually, of which 14-15 Tg/yr is from oxidation of monoterpenes and sesquiterpenes and 8-9 Tg/yr from isoprene.

  14. Global modeling of organic aerosol: the importance of reactive nitrogen

    Directory of Open Access Journals (Sweden)

    H. O. T. Pye

    2010-09-01

    Full Text Available Reactive nitrogen compounds, specifically NOx and NO3, likely influence global organic aerosol levels. To assess these interactions, GEOS-Chem, a chemical transport model, is updated to include improved biogenic emissions (following MEGAN v2.1/2.04, a new organic aerosol tracer lumping scheme, aerosol from nitrate radical (NO3 oxidation of isoprene, and NOx-dependent terpene aerosol yields. As a result of significant nighttime terpene emissions, fast reaction of monoterpenes with the nitrate radical, and relatively high aerosol yields from NO3 oxidation, biogenic hydrocarbon-NO3 reactions are expected to be a major contributor to surface level aerosol concentrations in anthropogenically influenced areas such as the United States. By including aerosol from nitrate radical oxidation in GEOS-Chem, terpene aerosol approximately doubles and isoprene aerosol is enhanced by 30 to 40% in the Southeast United States. In terms of the global budget of organic aerosol, however, aerosol from nitrate radical oxidation is somewhat minor (slightly more than 3 Tg/yr due to the relatively high volatility of organic-NO3 oxidation products. Globally, 69 to 88 Tg/yr of organic aerosol is predicted to be produced annually, of which 14–15 Tg/yr is from oxidation of monoterpenes and sesquiterpenes and 8–9 Tg/yr from isoprene.

  15. Clinical outcomes of pars plicata anterior vitrectomy: 2-year results

    Directory of Open Access Journals (Sweden)

    Priya Narang

    2015-01-01

    Full Text Available Purpose: To demonstrate the safety and outcome of a surgical approach that uses pars plicata site for anterior vitrectomy during phacoemulsification procedure complicated by posterior capsule rupture and residual cortical matter. Design: Single center, retrospective, interventional, noncomparative study. Materials and Methods: Medical records of a consecutive series of 35 eyes of 35 patients who underwent pars plicata anterior vitrectomy (PPAV were reviewed. The main outcome measures were corrected and uncorrected distance visual acuity (CDVA, UDVA, early and late postoperative complications and intraocular pressure (IOP. Ultrasound biomicroscopic (UBM evaluation of sclerotomy site and spectral domain optical coherence tomography analysis for central macular thickness (CMT was performed. The final visual outcome at 2 years was evaluated. Results: At 2 years follow-up, the mean postoperative UDVA (logarithm of the minimum angle of resolution [logMAR] and CDVA (logMAR was 0.49 ± 0.26 and 0.19 ± 0.14, respectively. There was no significant change in the IOP (P = 0.061 and the mean CMT at 2 years was 192.5 ± 5.54 mm. The postoperative UBM image of the sclerotomy site at 8 weeks demonstrated a clear wound without any vitreous adhesion or incarceration. Intraoperative hyphema was seen in 1 (2.8% case and postoperative uveitis was seen in 2 (5.7% cases, which resolved with medications. No case of an iatrogenic retinal break or retinal detachment was reported. Conclusions: PPAV enables a closed chamber approach, allows thorough cleanup of vitreous in the pupillary plane and anterior chamber and affords better access to the subincisional and retropupillary cortical remnant with a significant visual outcome and an acceptable complication rate.

  16. Importance of Raman Lidar Aerosol Extinction Measurements for Aerosol-Cloud Interaction Studies

    Directory of Open Access Journals (Sweden)

    Han Zaw

    2016-01-01

    Full Text Available Using a UV Raman Lidar for aerosol extinction, and combining Microwave Radiometer derived Liquid Water Path (LWP with Multifilter Rotating Shadowband Radiometer derived Cloud Optical depth, to get cloud effective radius (Reff, we observe under certain specialized conditions, clear signatures of the Twomey Aerosol Indirect effect on cloud droplet properties which are consistent with the theoretical bounds. We also show that the measurement is very sensitive to how far the aerosol layer is from the cloud base and demonstrate that surface PM25 is far less useful. Measurements from both the DOE ARM site and new results at CCNY are presented.

  17. Monthly-averaged anthropogenic aerosol direct radiative forcing over the Mediterranean from AERONET derived aerosol properties

    OpenAIRE

    Bergamo, A.; A. M. Tafuro; Kinne, S.; De Tomasi, F.; Perrone, M. R.

    2008-01-01

    The all-sky direct radiative effect by anthropogenic aerosol (DREa) is calculated in the solar (0.3–4 μm) and infrared (4–200 μm) spectral ranges for six Mediterranean sites. The sites are differently affected by pollution and together reflect typical aerosol impacts that are expected over land sites of the central Mediterranean basin. Central to the simulations are aerosol optical properties from AERONET sun-/sky-photometer statistics for the year 2003. A discussion on the variability of the...

  18. Monthly-averaged anthropogenic aerosol direct radiative forcing over the Mediterranean based on AERONET aerosol properties

    OpenAIRE

    Bergamo, A.; A. M. Tafuro; Kinne, S.; De Tomasi, F.; Perrone, M. R.

    2008-01-01

    The all-sky direct radiative effect by anthropogenic aerosol (DREa) is calculated in the solar (0.3–4 μm) and infrared (4–200 μm) spectral ranges for six Mediterranean sites. The sites are differently affected by pollution and together reflect typical aerosol impacts that are expected over land and coastal sites of the central Mediterranean basin. Central to the simulations are aerosol optical properties from AERONET sun-/sky-photometer statistics for the year 2003. A d...

  19. Solar PAR and UVR modify the community composition and photosynthetic activity of sea ice algae.

    Science.gov (United States)

    Enberg, Sara; Piiparinen, Jonna; Majaneva, Markus; Vähätalo, Anssi V; Autio, Riitta; Rintala, Janne-Markus

    2015-10-01

    The effects of increased photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) on species diversity, biomass and photosynthetic activity were studied in fast ice algal communities. The experimental set-up consisted of nine 1.44 m(2) squares with three treatments: untreated with natural snow cover (UNT), snow-free (PAR + UVR) and snow-free ice covered with a UV screen (PAR). The total algal biomass, dominated by diatoms and dinoflagellates, increased in all treatments during the experiment. However, the smaller biomass growth in the top 10-cm layer of the PAR + UVR treatment compared with the PAR treatment indicated the negative effect of UVR. Scrippsiella complex (mainly Scrippsiella hangoei, Biecheleria baltica and Gymnodinium corollarium) showed UV sensitivity in the top 5-cm layer, whereas Heterocapsa arctica ssp. frigida and green algae showed sensitivity to both PAR and UVR. The photosynthetic activity was highest in the top 5-cm layer of the PAR treatment, where the biomass of the pennate diatom Nitzschia frigida increased, indicating the UV sensitivity of this species. This study shows that UVR is one of the controlling factors of algal communities in Baltic Sea ice, and that increased availability of PAR together with UVR exclusion can cause changes in algal biomass, photosynthetic activity and community composition. PMID:26310455

  20. Participatory Action Research (PAR) cum Action Research (AR) in Teacher Professional Development: A Literature Review

    Science.gov (United States)

    Morales, Marie Paz E.

    2016-01-01

    This paper reviews Participatory Action Research as an approach to teacher professional development. It maps the origins of Participatory Action Research (PAR) and discusses the benefits and challenges that have been identified by other researchers in utilizing PAR approaches in conducting research. It draws ideas of combining the features of…

  1. Dark Targets, Aerosols, Clouds and Toys

    Science.gov (United States)

    Remer, L. A.

    2015-12-01

    Today if you use the Thomson-Reuters Science Citations Index to search for "aerosol*", across all scientific disciplines and years, with no constraints, and you sort by number of citations, you will find a 2005 paper published in the Journal of the Atmospheric Sciences in the top 20. This is the "The MODIS Aerosol Algorithm, Products and Validation". Although I am the first author, there are in total 12 co-authors who each made a significant intellectual contribution to the paper or to the algorithm, products and validation described. This paper, that algorithm, those people lie at the heart of a lineage of scientists whose collaborations and linked individual pursuits have made a significant contribution to our understanding of radiative transfer and climate, of aerosol properties and the global aerosol system, of cloud physics and aerosol-cloud interaction, and how to measure these parameters and maximize the science that can be obtained from those measurements. The 'lineage' had its origins across the globe, from Soviet Russia to France, from the U.S. to Israel, from the Himalayas, the Sahel, the metropolises of Sao Paulo, Taipei, and the cities of east and south Asia. It came together in the 1990s and 2000s at the NASA Goddard Space Flight Center, using cultural diversity as a strength to form a common culture of scientific creativity that continues to this day. The original algorithm has spawned daughter algorithms that are being applied to new satellite and airborne sensors. The original MODIS products have been fundamental to analyses as diverse as air quality monitoring and aerosol-cloud forcing. AERONET, designed originally for the need of validation, is now its own thriving institution, and the lineage continues to push forward to provide new technology for the coming generations.

  2. Formation of the natural sulfate aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Kerminen, V.M.; Hillamo, R.; Maekinen, M.; Virkkula, A.; Maekelae, T.; Pakkanen, T. [Helsinki Univ. (Finland). Dept. of Physics

    1996-12-31

    Anthropogenic sulfate aerosol, together with particles from biomass burning, may significantly reduce the climatic warming due to man-made greenhouse gases. The radiative forcing of aerosol particles is based on their ability to scatter and absorb solar radiation (direct effect), and on their influences on cloud albedos and lifetimes (indirect effect). The direct aerosol effect depends strongly on the size, number and chemical composition of particles, being greatest for particles of 0.1-1 {mu}m in diameter. The indirect aerosol effect is dictated by the number of particles being able to act as cloud condensation nuclei (CCN). For sulfate particles, the minimum CCN size in tropospheric clouds is of the order of 0.05-0.2 {mu}m. To improve aerosol parameterizations in future climate models, it is required that (1) both primary and secondary sources of various particle types will be characterized at a greater accuracy, and (2) the influences of various atmospheric processes on the spatial and temporal distribution of these particles and their physico-chemical properties are known much better than at the present. In estimating the climatic forcing due to the sulfate particles, one of the major problems is to distinguish between sulfur from anthropogenic sources and that of natural origin. Global emissions of biogenic and anthropogenic sulfate pre-cursors are comparable in magnitude, but over regional scales either of these two source types may dominate. The current presentation is devoted to discussing the natural sulfate aerosol, including the formation of sulfur-derived particles in the marine environment, and the use of particulate methanesulfonic acid (MSA) as a tracer for the natural sulfate

  3. Use of aerosols in lung function studies

    International Nuclear Information System (INIS)

    Since aerosol inhalation lung scintigraphy was introduced in 1965 following perfusion lung imaging, both imaging modalities have offered powerful tools not only for the study of respiratory lung function but also for the exploration of non-respiratory lung function studies. Visualization of the distribution of ventilation and perfusion in the lungs has made it possible to determine whether ventilation and perfusion are well matched or not, thus leading to the diagnosis of vascular diseases if perfusion is absent in the well ventilated lung regions, whereas airway diseases show matched ventilation and perfusion abnormalities. The reasons for the above principles have been physiologically clarified by perfusion and inhalation techniques using radioactive particulates, aerosols and radioactive gases. Regional ventilation always regulates regional perfusion; regional hypoventilation causes regional hypoxia which in turn causes hypoxic vasoconstriction and a consequent decrease in perfusion. Regional perfusion does not regulate regional ventilation except in the very early phase of perfusion changes when hypoperfusion can cause a transient bronchoconstriction and hypoventilation. This reaction disappears within 6 hours in dogs. Deposition patterns of inhaled aerosol in the lungs help differentiate the nature of the obstructive airways disease. Aerosol inhalation imaging can offer a unique technique for the study of mucociliary clearance function in the lungs. 'Radioaerosol inhalation lung cinescintigraphy' has made it possible to visualize the actual mucociliary clearance status in the lungs in vivo. Indexes to quantify the mucociliary clearance function have been proposed. Effects of pharmaceutical agents on mucociliary clearance function in the lungs can now be objectively evaluated by aerosol inhalation lung imaging and its quantification. The study of pulmonary epithelial permeability by inhalation of 99Tcm DTPA aerosol has also been mentioned. 26 refs, 8 figs, 3

  4. Preparation and characterization of magnetizable aerosols.

    Science.gov (United States)

    Baumann, Romy; Glöckl, Gunnar; Nagel, Stefan; Weitschies, Werner

    2012-04-11

    Magnetizable aerosols can be used for inhalative magnetic drug targeting in order to enhance the drug concentration at a certain target site within the lung. The aim of the present study was to clarify how a typical ferrofluid can be atomized in a reproducible way. The influence of the atomization principle, the concentration of magnetic nanoparticles within the carrier liquid and the addition of commonly used pharmaceutical excipients on the aerosol droplet size were investigated. Iron oxide (magnetite) nanoparticles were synthesized by alkaline precipitation of mixtures of iron(II)- and iron(III)-chloride and coated with citric acid. The resulting ferrofluid was characterized by photon correlation spectroscopy and vibrating sample magnetometry. Two different nebulizers (Pari Boy and eFlow) with different atomization principles were used to generate ferrofluid aerosols. A range of substances that influence the surface tension, viscosity, density or vapor pressure of the ferrofluid were added to investigate their impact on the generated aerosol droplets. The particle size was determined by laser diffraction. A stable ferrofluid with a magnetic core diameter of 10.7 ± 0.45 nm and a hydrodynamic diameter of 124 nm was nebulized by Pari Boy and eFlow. The aerosol droplet size of Pari Boy was approximately 2.5 μm and remained unaffected by the addition of substances that changed the physical properties of the solvent. The droplet size of aerosols generated by eFlow was approximately 5 μm. It was significantly reduced by the addition of Cremophor RH 40, glycerol, polyvinyl pyrrolidone and ethanol. PMID:22306649

  5. TEM investigations of microstructures of combustion aerosols

    International Nuclear Information System (INIS)

    In the incineration of organic material, apart from a series of gaseous pollutants, particulate pollutants or combustion aerosols also arise. The latter frequently consist of particles with a solid core of carbon to which a large number of inorganic and organic compounds are attached. These primarily include the polycyclic aromatic hydrocarbons (PAH) and their nitro-derivatives (NPAH), whose mutagenic or carcinogenic effect is known. The invisible particle sizes in the nanometer range, whose retention in the incineration off-gas is not state of the art, are of increasing significance for man and environment. On the one hand, they are deposited almost completely in the human lung. On the other hand, due to their fine dispersity they have along residence time in the atmosphere where they participate in chemical reactions and climatically significant processes. Important insights about the formation process of combustion aerosols are to be expected from the imaging of their microstructures in the transmission electron microscope (TEM). The present contribution describes the development and application of a representative sampling procedure for aerosols from a partial flow of flue gas from a fluidized-bed furnace. The method developed consists of electrically charging aerosol particles in situ and subsequently selectively precipitating them onto a microscope slide in an electric field. TEM studies of aerosol microstructures on the microscope slides revealed that in the combustion of petrol and heating oil under different combustion conditions in principle the same particle structures result, whereas in the incineration of used lubricating oil quite different particle structures were found. Results from the literature on aerosol microstructures in exhaust gases from petrol and diesel engines demonstrate agreement with the results of this study in the basic structure of the particles. (orig.)

  6. Comparison of Aerosol Classification From Airborne High Spectral Resolution Lidar and the CALIPSO Vertical Feature Mask

    Science.gov (United States)

    Burton, Sharon P.; Ferrare, Rich A.; Omar, Ali H.; Vaughan, Mark A.; Rogers, Raymond R.; Hostetler, Chris a.; Hair, Johnathan W.; Obland, Michael D.; Butler, Carolyn F.; Cook, Anthony L.; Harper, David B.

    2012-01-01

    Knowledge of aerosol composition and vertical distribution is crucial for assessing the impact of aerosols on climate. In addition, aerosol classification is a key input to CALIOP aerosol retrievals, since CALIOP requires an inference of the lidar ratio in order to estimate the effects of aerosol extinction and backscattering. In contrast, the NASA airborne HSRL-1 directly measures both aerosol extinction and backscatter, and therefore the lidar ratio (extinction-to-backscatter ratio). Four aerosol intensive properties from HSRL-1 are combined to infer aerosol type. Aerosol classification results from HSRL-1 are used here to validate the CALIOP aerosol type inferences.

  7. In situ aerosol characterization at Cape Verde Part 2: Parametrization of relative humidity- and wavelength-dependent aerosol optical properties

    OpenAIRE

    Schladitz, Alexander; Müller, Thomas; Nordmann, Stephan; Tesche, Matthias; Groß, Silke; Freudenthaler, Volker; Gasteiger, Josef; Wiedensohler, Alfred

    2011-01-01

    An observation-based numerical study of humidity-dependent aerosol optical properties of mixed marine and Saharan mineral dust aerosol is presented. An aerosol model was developed based on measured optical and microphysical properties to describe the marine and Saharan dust aerosol at Cape Verde. A wavelength-dependent optical equivalent imaginary part of the refractive index and a scattering non-sphericity factor for Saharan dust were derived. Simulations of humidity effects on optical prope...

  8. On use of the method of acoustic coagulation of aerosols for purification of gaseous wastes from highly dispersed radioactive aerosols

    International Nuclear Information System (INIS)

    Acoustic coagulation of radioactive highly dispersed aerosols was investigated experimentally. Dispersive composition of aerosols before and after systems of collection by standard methods was determined. Efficiency of purification of gaseous wastes from radioactive highly dispersed aerosols using the method of acoustic coagulation in conjunction with standard purification methods was estimated. This method permitted to raise an efficiency of purification of gaseous flows from difficultly collected radioactive aerosols with particle sizes 2

  9. TEM Study of SAFARI-2000 Aerosols

    Science.gov (United States)

    Buseck, Peter R.

    2004-01-01

    The aim of our research was to obtain data on the chemical and physical properties of individual aerosol particles from biomass smoke plume s in southern Africa and from air masses in the region that are affec ted by the smoke. We used analytical transmission electron microscopy (ATEM), including energy-dispersive X-ray spectrometry (EDS) and ele ctron energy-loss spectroscopy (EELS), and field-emission electron microscopy (FESEM) to study aerosol particles from several smoke and haz e samples and from a set of cloud samples.

  10. Pharmacokinetics of aerosol amphotericin B in rats.

    OpenAIRE

    Niki, Y.; Bernard, E M; Schmitt, H J; Tong, W P; Edwards, F F; Armstrong, D

    1990-01-01

    The distributions of amphotericin B (AmB) in tissue were compared after intraperitoneal or aerosol administration. Rats were sacrificed 24 h after receiving single or repeated daily doses; AmB concentrations in tissues were determined by high-performance liquid chromatography. After intraperitoneal doses of 4 mg/kg of body weight per day for 7 days, mean concentrations of AmB were 122.7, 55.2, and 4.31 micrograms/g in the spleen, liver, and lung, respectively. After aerosol doses (aero-AmB) o...

  11. Aerosol delivery of synthetic lung surfactant

    Directory of Open Access Journals (Sweden)

    Frans J. Walther

    2014-05-01

    Full Text Available Background. Nasal continuous positive airway pressure (nCPAP is a widely accepted technique of non-invasive respiratory support in premature infants with respiratory distress syndrome due to lack of lung surfactant. If this approach fails, the next step is often intubation, mechanical ventilation (MV and intratracheal instillation of clinical lung surfactant. Objective. To investigate whether aerosol delivery of advanced synthetic lung surfactant, consisting of peptide mimics of surfactant proteins B and C (SP-B and SP-C and synthetic lipids, during nCPAP improves lung function in surfactant-deficient rabbits. Methods. Experimental synthetic lung surfactants were produced by formulating 3% Super Mini-B peptide (SMB surfactant, a highly surface active SP-B mimic, and a combination of 1.5% SMB and 1.5% of the SP-C mimic SP-Css ion-lock 1 (BC surfactant, with a synthetic lipid mixture. After testing aerosol generation using a vibrating membrane nebulizer and aerosol conditioning (particle size, surfactant composition and surface activity, we investigated the effects of aerosol delivery of synthetic SMB and BC surfactant preparations on oxygenation and lung compliance in saline-lavaged, surfactant-deficient rabbits, supported with either nCPAP or MV. Results. Particle size distribution of the surfactant aerosols was within the 1–3 µm distribution range and surfactant activity was not affected by aerosolization. At a dose equivalent to clinical surfactant therapy in premature infants (100 mg/kg, aerosol delivery of both synthetic surfactant preparations led to a quick and clinically relevant improvement in oxygenation and lung compliance in the rabbits. Lung function recovered to a greater extent in rabbits supported with MV than with nCPAP. BC surfactant outperformed SMB surfactant in improving lung function and was associated with higher phospholipid values in bronchoalveolar lavage fluid; these findings were irrespective of the type of

  12. Delivery of aerosolized drugs encapsulated in liposomes

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yung-Sung; Lyons, C.R. [Univ. of New Mexico, Albuquerque, NM (United States); Schmid, M.H.

    1995-12-01

    Mycobacterium tuberculosis (Mtb) is an infectious disease that resides in the human lung. Due to the difficulty in completely killing off the disease in infected individuals, Mtb has developed drug-resistant forms and is on the rise in the human population. Therefore, ITRI and the University of New Mexico are collaborating to explore the treatment of Mtb by an aerosolized drug delivered directly to the lungs. In conclusion, it is feasible to obtain an appropriate size and concentration of the liposomes before and after aerosolization.

  13. Aerosol behaviour in an acoustic field

    International Nuclear Information System (INIS)

    The average size of an aerosol submitted to acoustic waves is increased. This results from coagulation of the finest particles on the largest ones. The mechanisms responsible for acoustic agglomeration are mentioned. An experimental apparatus was developed in order to control the evolution of aerosol distribution in an acoustic field. Important deposition on the walls of the agglomeration chamber was observed as a consequence of the acoustically induced turbulent flow. Finally, a dimensionless relationship was established between deposition rates and particle diameters as a function of experimental parameters (aeraulic and acoustic conditions, etc...)

  14. Compression Myelopathy due to Proliferative Changes around C2 Pars Defects without Instability

    Science.gov (United States)

    Kimura, Tetsuya; Tezuka, Fumitake; Abe, Mitsunobu; Yamashita, Kazuta; Takata, Yoichiro; Higashino, Kosaku; Sairyo, Koichi

    2016-01-01

    We report a case with compression myelopathy due to proliferative changes around the C2 pars defects without instability. A 69-year-old man presented with progressive clumsy hands and spastic gait. Plain radiographs showed bilateral spondylolysis (pars defects) at C2 and fusion between C2 and C3 spinous processes. Dynamic views revealed mobility through the pars defects, but there was no apparent instability. Computed tomography showed proliferative changes at the pars defects, which protruded into spinal canal. On magnetic resonance imaging, the spinal cord was compressed and intramedullary high signal change was found. A diagnosis of compression myelopathy due to proliferative changes around the C2 pars defects was made. We performed posterior decompression. Postoperatively, symptoms have been alleviated and images revealed sufficient decompression and no apparent instability. In patients with the cervical spondylolysis, myelopathy caused by instability or slippage have been periodically reported. The present case involving C2 spondylolysis is extremely rare. PMID:27340539

  15. Estimating photosynthetically active radiation (PAR) at the Earth's surface from satellite observations

    International Nuclear Information System (INIS)

    Current satellite algorithms to estimate photosynthetically active radiation (PAR) at the Earth's surface are reviewed, and selected results are presented. PAR can be obtained directly from top-of-atmosphere solar radiance, which is used to determine the transmissivity of the atmosphere. Since clouds do not absorb significantly at PAR wavelengths, the radiative transfer modeling is generally simplified compared to that for total insolation. The accuracies reported, about 10% and 6% on daily and monthly time scales, respectively, are useful for modeling oceanic and terrestrial primary productivity. The large short-term variability in the ratio of PAR and insolation, essentially due to clouds, is reduced at those time scales, suggesting that reasonably accurate PAR climatologies may be obtained from available insolation climatologies (satellite or other). (author)

  16. Compression Myelopathy due to Proliferative Changes around C2 Pars Defects without Instability.

    Science.gov (United States)

    Kimura, Tetsuya; Sakai, Toshinori; Tezuka, Fumitake; Abe, Mitsunobu; Yamashita, Kazuta; Takata, Yoichiro; Higashino, Kosaku; Sairyo, Koichi

    2016-06-01

    We report a case with compression myelopathy due to proliferative changes around the C2 pars defects without instability. A 69-year-old man presented with progressive clumsy hands and spastic gait. Plain radiographs showed bilateral spondylolysis (pars defects) at C2 and fusion between C2 and C3 spinous processes. Dynamic views revealed mobility through the pars defects, but there was no apparent instability. Computed tomography showed proliferative changes at the pars defects, which protruded into spinal canal. On magnetic resonance imaging, the spinal cord was compressed and intramedullary high signal change was found. A diagnosis of compression myelopathy due to proliferative changes around the C2 pars defects was made. We performed posterior decompression. Postoperatively, symptoms have been alleviated and images revealed sufficient decompression and no apparent instability. In patients with the cervical spondylolysis, myelopathy caused by instability or slippage have been periodically reported. The present case involving C2 spondylolysis is extremely rare. PMID:27340539

  17. Atmospheric oxidation of isoprene and 1,3-Butadiene: influence of aerosol acidity and Relative humidity on secondary organic aerosol

    Science.gov (United States)

    The effects of acidic seed aerosols on the formation of secondary organic aerosol (SOA)have been examined in a number of previous studies, several of which have observed strong linear correlations between the aerosol acidity (measured as nmol H+ per m3 air s...

  18. UV Aerosol Indices from SCIAMACHY: introducing the SCattering Index (SCI

    Directory of Open Access Journals (Sweden)

    T. Wagner

    2009-12-01

    Full Text Available The Absorbing Aerosol Index (AAI is a useful tool for detecting aerosols that absorb UV radiation – especially in cases where other aerosol retrievals fail, such as over bright surfaces (e.g. desert and in the presence of clouds. The AAI does not, however, consider contributions from scattering (hardly absorbing aerosols and clouds: they cause negative AAI values and are usually disregarded. In this paper, we demonstrate the use of the AAI's negative counterpart, the SCattering Index (SCI to detect scattering aerosols. Consideration of the full UV Aerosol Index scale is of importance if the Aerosol Index is to be used for the quantification of aerosol absorption in the future.

    Maps of seasonally averaged SCI show significantly enhanced values in summer in Southeast USA and Southeast Asia, pointing to a high production of scattering aerosols (presumably mainly sulphate aerosols and secondary organic aerosols in this season. The application of a cloud filter makes the presence of scattering aerosols even more clear. Radiative transfer calculations were performed to investigate the sensitivity of AAI and SCI to cloud parameters, and it is demonstrated that clouds cause significant SCI, in some special cases even small AAI values. The results from cloud modelling imply that cloud effects need to be taken into account when AAI and SCI are used in a quantitative manner.

    The paper concludes with a comparison of aerosol parameters from AERONET and our Aerosol Indices (AAI and SCI from SCIAMACHY, where reasonable agreement was found for six AERONET stations in Southeast USA, Southeast Asia, and Africa. These findings corroborate the suitability of SCI as a tool to detect scattering aerosols.

  19. Aerosol Remote Sensing in Polar Regions

    Science.gov (United States)

    Tomasi, Claudio; Kokhanovsky, Alexander A.; Lupi, Angelo; Ritter, Christoph; Smirnov, Alexander; O'Neill, Norman T.; Stone, Robert S.; Holben, Brent N.; Nyeki, Stephan; Wehrli, Christoph

    2014-01-01

    Multi-year sets of ground-based sun-photometer measurements conducted at 12 Arctic sites and 9 Antarctic sites were examined to determine daily mean values of aerosol optical thickness tau(lambda) at visible and near-infrared wavelengths, from which best-fit values of Ångström's exponent alpha were calculated. Analyzing these data, the monthly mean values of tau(0.50 micrometers) and alpha and the relative frequency histograms of the daily mean values of both parameters were determined for winter-spring and summer-autumn in the Arctic and for austral summer in Antarctica. The Arctic and Antarctic covariance plots of the seasonal median values of alpha versus tau(0.50 micrometers) showed: (i) a considerable increase in tau(0.50 micrometers) for the Arctic aerosol from summer to winter-spring, without marked changes in alpha; and (ii) a marked increase in tau(0.50 micrometer) passing from the Antarctic Plateau to coastal sites, whereas alpha decreased considerably due to the larger fraction of sea-salt aerosol. Good agreement was found when comparing ground-based sun-photometer measurements of tau(lambda) and alpha at Arctic and Antarctic coastal sites with Microtops measurements conducted during numerous AERONET/MAN cruises from 2006 to 2013 in three Arctic Ocean sectors and in coastal and off-shore regions of the Southern Atlantic, Pacific, and Indian Oceans, and the Antarctic Peninsula. Lidar measurements were also examined to characterize vertical profiles of the aerosol backscattering coefficient measured throughout the year at Ny-Ålesund. Satellite-based MODIS, MISR, and AATSR retrievals of tau(lambda) over large parts of the oceanic polar regions during spring and summer were in close agreement with ship-borne and coastal ground-based sun-photometer measurements. An overview of the chemical composition of mode particles is also presented, based on in-situ measurements at Arctic and Antarctic sites. Fourteen log-normal aerosol number size-distributions were

  20. Analyses of CsI aerosol deposition in aerosol behavior tests in WIND project

    International Nuclear Information System (INIS)

    The aerosol deposition tests have been performed in WIND project at JAERI to characterize the aerosol behavior. The aerosol deposition tests named WAV1-D and WAV2-D were analyzed by aerosol behavior analysis codes, JAERI's ART and SNL's VICTORIA. The comparison calculation was performed for the confirmation of the analytical capabilities of the both codes and improvement of the models in ART. The deposition mass calculated by ART was larger than that by VICTORIA. This discrepancy is caused by differences in model for FP vapor condensation onto the wall surface. In the WAV2-D test, in which boric acid was placed on the floor area of the test section prior to the deposition phase to simulate the PWR primary coolant, there was a discrepancy in deposition mass between analytical results in both codes and experimental results. The discrepancy may be caused by existence of boric acid which is not considered in the codes. (author)

  1. Aerosol isotopic ammonium signatures over the remote Atlantic Ocean

    Science.gov (United States)

    Lin, C. T.; Jickells, T. D.; Baker, A. R.; Marca, A.; Johnson, M. T.

    2016-05-01

    We report aerosol ammonium 15N signatures for samples collected from research cruises on the South Atlantic and Caribbean using a new high sensitivity method. We confirm a pattern of isotopic signals from generally light (δ15N -5 to -10‰), for aerosols with very low (ocean, to generally heavier values (δ15N +5 to +10‰), for aerosols collected in temperate and tropical latitudes and with higher ammonium concentrations (>2  nmol m-3). We discuss whether this reflects a mixing of aerosols from two end-members (polluted continental and remote marine emissions), or isotopic fractionation during aerosol transport.

  2. Determination of Aerosol Particle Diameter Using Cascade Impactor Procedure

    International Nuclear Information System (INIS)

    Determination of aerosol particle size distribution has been done using a low pressure Andersen's cascade impactor with 13 stages. The aerosol has been sampled with flow rate of aerosol sampling of 28.3 Ipm. Preliminary study result shows that aerosol in the simulation chamber was spread in monomodal distribution with Mass Median Aerodynamic Diameter of 4.9 μm. The aerosol measurement in Japan Power Demonstration Reactor has been spread in trimodal distribution with Activity Median Aerodynamic Diameter equal to 13.3 μm. The use of mylar as impaction plate instead of aluminum foil gives good result

  3. Intercomparison of CALIOP and MODIS aerosol optical depth retrievals

    OpenAIRE

    Kittaka, C.; Winker, D. M.; M. A. Vaughan; Omar, A.; Remer, L. A.

    2010-01-01

    The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) is carried on the CALIPSO satellite and has acquired global aerosol profiles since June 2006. CALIPSO is flown in formation with the Aqua satellite as part of the A-train satellite constellation, so that a large number of coincident aerosol observations are available from CALIOP and the MODIS-Aqua instrument. This study compares column aerosol optical depth at 0.532 μm derived from CALIOP aerosol profiles with MODIS-Aqua 0.55 μm ae...

  4. Aerosol/Cloud Measurements Using Coherent Wind Doppler Lidars

    Science.gov (United States)

    Royer, Philippe; Boquet, Matthieu; Cariou, Jean-Pierre; Sauvage, Laurent; Parmentier, Rémy

    2016-06-01

    The accurate localization and characterization of aerosol and cloud layers is crucial for climate studies (aerosol indirect effect), meteorology (Planetary Boundary Layer PBL height), site monitoring (industrial emissions, mining,…) and natural hazards (thunderstorms, volcanic eruptions). LEOSPHERE has recently developed aerosol/cloud detection and characterization on WINDCUBE long range Coherent Wind Doppler Lidars (CWDL). These new features combine wind and backscatter intensity informations (Carrier-to-Noise Ratio CNR) in order to detect (aerosol/cloud base and top, PBL height) and to characterize atmospheric structures (attenuated backscatter, depolarization ratio). For each aerosol/cloud functionality the method is described, limitations are discussed and examples are given to illustrate the performances.

  5. Radioactive aerosols of 'Ukryttya' object in 1986-2006 years

    International Nuclear Information System (INIS)

    Radioactive aerosols of 'Ukryttya' object in its premises and its industrial site are seen. In seven parts the mechanisms and sources of aerosol generation at explosion of the block 4 of the ChNPP in 1986, at building and operation of 'Ukryttya' object are presented. The dynamics of radionuclide composition, concentrations and size distributions are analyzed. The means and methods for aerosol sampling, using of collective and personal protection devices, the problems of control of radioactive aerosol inhalation are seen. The main attention is paid to aerosols with diameter up to 10 mkm

  6. Influence of aerosol upon radon concentration of radon chamber

    International Nuclear Information System (INIS)

    On the basis of theoretical analysis, the influence on the radon concentration of radon chamber by the experiment of filling the radon chamber with aerosol, and the absorption of radon daughter on aerosol under the condition of different radon concentration and aerosol concentration was described. The results of experiment showed that: Aerosol did not affect the stability of the radon concentration of the radon chamber, but different aerosol concentration will change the combination state of radon daughter, thus it will affect the diffusion coefficient of radon daughter, so it will affect the results of the measure of the gross measuring instrument. (authors)

  7. Do anthropogenic or coastal aerosol sources impact on a clean marine aerosol signature at Mace Head?

    Science.gov (United States)

    O'Dowd, C.; Ceburnis, D.; Ovadnevaite, J.; Rinaldi, M.; Facchini, M. C.

    2013-03-01

    Atmospheric aerosols have been sampled and characterised at the Mace Head North East (N.E.) Atlantic atmospheric research station since 1958, with many interesting phenomena being discovered. However, with the range of new discoveries and scientific advances, there has been a range of concomitant criticisms challenging the representativeness of aerosol sampled at the station to that of aerosol over the open ocean. Two recurring criticisms relate to the lack of representativeness due to enhanced coastal sources, thereby leading to artificially high values to aerosol parameters, and to the influence of long-range transport of anthropogenic aerosol and its potential dominance over, or drowning-out of, a natural marine aerosol signal. Here we review the results of previous experimental studies into marine aerosols over the N.E. Atlantic and at Mace Head with the aim of evaluating their representativeness relative to that of an open ocean aerosol with negligible anthropogenic influence. Particular focus is given to organic matter (OM) aerosol. In summary, no correlation was found between OM and black carbon (BC) either at BC levels of 0-15 or 15-50 ng m-3, suggesting that OM concentrations up to peak values of 3.8 μg m-3 are predominantly natural in origin. Sophisticated carbon isotope analysis and aerosol mass spectral finger printing corroborate the natural source of OM with 80% biogenic source apportionment being observed for general clean air conditions, rising to 98% during specific primary marine organic plumes when peak concentrations >3 μg m-3 are observed. A range of other experiments are discussed which corroborate the dominance of a marine signal under Mace Head clean air criteria along. Further, analysis of a series of experiments conducted at Mace Head conclude that negligible coastal, surf zone, or tidal effects are discernible in the submicron size range for sampling heights of 7 m and above. The Mace Head clean air criteria ensures anthropogenic and

  8. Do anthropogenic or coastal aerosol sources impact on a clean marine aerosol signature at Mace Head?

    Directory of Open Access Journals (Sweden)

    C. O'Dowd

    2013-03-01

    Full Text Available Atmospheric aerosols have been sampled and characterised at the Mace Head North East (N.E. Atlantic atmospheric research station since 1958, with many interesting phenomena being discovered. However, with the range of new discoveries and scientific advances, there has been a range of concomitant criticisms challenging the representativeness of aerosol sampled at the station to that of aerosol over the open ocean. Two recurring criticisms relate to the lack of representativeness due to enhanced coastal sources, thereby leading to artificially high values to aerosol parameters, and to the influence of long-range transport of anthropogenic aerosol and its potential dominance over, or drowning-out of, a natural marine aerosol signal. Here we review the results of previous experimental studies into marine aerosols over the N.E. Atlantic and at Mace Head with the aim of evaluating their representativeness relative to that of an open ocean aerosol with negligible anthropogenic influence. Particular focus is given to organic matter (OM aerosol. In summary, no correlation was found between OM and black carbon (BC either at BC levels of 0–15 or 15–50 ng m−3, suggesting that OM concentrations up to peak values of 3.8 μg m−3 are predominantly natural in origin. Sophisticated carbon isotope analysis and aerosol mass spectral finger printing corroborate the natural source of OM with 80% biogenic source apportionment being observed for general clean air conditions, rising to 98% during specific primary marine organic plumes when peak concentrations >3 μg m−3 are observed. A range of other experiments are discussed which corroborate the dominance of a marine signal under Mace Head clean air criteria along. Further, analysis of a series of experiments conducted at Mace Head conclude that negligible coastal, surf zone, or tidal effects are discernible in the submicron size range for sampling heights of 7 m and above. The Mace Head clean air criteria

  9. Aerosol climatology: on the discrimination of aerosol types over four AERONET sites

    Directory of Open Access Journals (Sweden)

    D. G. Kaskaoutis

    2007-05-01

    Full Text Available Aerosols have a significant regional and global effect on climate, which is about equal in magnitude but opposite in sign to that of greenhouse gases. Nevertheless, the aerosol climatic effect changes strongly with space and time because of the large variability of aerosol physical and optical properties, which is due to the variety of their sources, which are natural, and anthropogenic, and their dependence on the prevailing meteorological and atmospheric conditions. Characterization of aerosol properties is of major importance for the assessment of their role for climate. In the present study, 3-year AErosol RObotic NETwork (AERONET data from ground-based sunphotometer measurements are used to establish climatologies of aerosol optical depth (AOD and Ångström exponent α in several key locations of the world, characteristic of different atmospheric environments. Using daily mean values of AOD at 500 nm (AOD500 and Ångström exponent at the pair of wavelengths 440 and 870 nm (α 440–870, a discrimination of the different aerosol types occurring in each location is achieved. For this discrimination, appropriate thresholds for AOD500 and α 440–870 are applied. The discrimination of aerosol types in each location is made on an annual and seasonal basis. It is shown that a single aerosol type in a given location can exist only under specific conditions (e.g. intense forest fires or dust outbreaks, while the presence of well-mixed aerosols is the accustomed situation. Background clean aerosol conditions (AOD500<0.06 are mostly found over remote oceanic surfaces occurring on average in ~56.7% of total cases, while this situation is quite rare over land (occurrence of 3.8–13.7%. Our analysis indicates that these percentages change significantly from season to season. The spectral dependence of AOD exhibits large differences between the examined locations, while it exhibits a strong

  10. Aerosol physical and optical properties in the Eastern Mediterranean Basin, Crete, from Aerosol Robotic Network data

    Directory of Open Access Journals (Sweden)

    A. Fotiadi

    2006-01-01

    Full Text Available In this study, we investigate the aerosol optical properties, namely aerosol extinction optical thickness (AOT, Angström parameter and size distribution over the Eastern Mediterranean Basin, using spectral measurements from the recently established FORTH (Foundation for Research and Technology-Hellas AERONET station in Crete, for the two-year period 2003–2004. The location of the FORTH-AERONET station offers a unique opportunity to monitor aerosols from different sources. Maximum values of AOT are found primarily in spring, which together with small values of the Angström parameter indicate dust transported from African deserts, whereas the minimum values of AOT occur in winter. In autumn, large AOT values observed at near-infrared wavelengths arise also from dust transport. In summer, large AOT values at ultraviolet (340 nm and visible wavelengths (500 nm, together with large values of the Angström parameter, are associated with transport of fine aerosols of urban/industrial and biomass burning origin. The Angström parameter values vary on a daily basis within the range 0.05–2.20, and on a monthly basis within the range 0.68–1.9. This behaviour, together with broad frequency distributions and back-trajectory analyses, indicates a great variety of aerosol types over the study region including dust, urban-industrial and biomass-burning pollution, and maritime, as well as mixed aerosol types. Large temporal variability is observed in AOT, Angström parameter, aerosol content and size. The fine and coarse aerosol modes persist throughout the year, with the coarse mode dominant except in summer. The highest values of AOT are related primarily to southeasterly winds, associated with coarse aerosols, and to a less extent to northwesterly winds associated with fine aerosols. The results of this study show that the FORTH AERONET station in Crete is well suited for studying the transport and mixing of different types of aerosols from a variety

  11. AEROSOL MEASUREMENTS IN THE SUBMICRON SIZE RANGE, STUDIES WITH AN AEROSOL CENTRIFUGE, A NEW DIFFUSION BATTERY, A LOW PRESSURE IMPACTOR AND AN ADVANCED CONDENSATION NUCLEI COUNTER

    Science.gov (United States)

    The report summarizes the investigations of four aerosol classifiers which cover finite, but overlapping ranges of the aerosol particle size spectrum. The first part is concerned with a cylindrical aerosol centrifuge, which measures aerodynamic equivalent diameters precisely. Thi...

  12. Release of Free DNA by Membrane-Impaired Bacterial Aerosols Due to Aerosolization and Air Sampling

    OpenAIRE

    Zhen, Huajun; Han, Taewon; Fennell, Donna E.; Mainelis, Gediminas

    2013-01-01

    We report here that stress experienced by bacteria due to aerosolization and air sampling can result in severe membrane impairment, leading to the release of DNA as free molecules. Escherichia coli and Bacillus atrophaeus bacteria were aerosolized and then either collected directly into liquid or collected using other collection media and then transferred into liquid. The amount of DNA released was quantified as the cell membrane damage index (ID), i.e., the number of 16S rRNA gene copies in ...

  13. Recent Improvements to CALIOP Level 3 Aerosol Profile Product for Global 3-D Aerosol Extinction Characterization

    Science.gov (United States)

    Tackett, J. L.; Getzewich, B. J.; Winker, D. M.; Vaughan, M. A.

    2015-12-01

    With nine years of retrievals, the CALIOP level 3 aerosol profile product provides an unprecedented synopsis of aerosol extinction in three dimensions and the potential to quantify changes in aerosol distributions over time. The CALIOP level 3 aerosol profile product, initially released as a beta product in 2011, reports monthly averages of quality-screened aerosol extinction profiles on a uniform latitude/longitude grid for different cloud-cover scenarios, called "sky conditions". This presentation demonstrates improvements to the second version of the product which will be released in September 2015. The largest improvements are the new sky condition definitions which parse the atmosphere into "cloud-free" views accessible to passive remote sensors, "all-sky" views accessible to active remote sensors and "cloudy-sky" views for opaque and transparent clouds which were previously inaccessible to passive remote sensors. Taken together, the new sky conditions comprehensively summarize CALIOP aerosol extinction profiles for a broad range of scientific queries. In addition to dust-only extinction profiles, the new version will include polluted-dust and smoke-only extinction averages. A new method is adopted for averaging dust-only extinction profiles to reduce high biases which exist in the beta version of the level 3 aerosol profile product. This presentation justifies the new averaging methodology and demonstrates vertical profiles of dust and smoke extinction over Africa during the biomass burning season. Another crucial advancement demonstrated in this presentation is a new approach for computing monthly mean aerosol optical depth which removes low biases reported in the beta version - a scenario unique to lidar datasets.

  14. Reallocation in modal aerosol models: impacts on predicting aerosol radiative effects

    OpenAIRE

    Korhola, T.; H. Kokkola; Korhonen, H.; A.-I. Partanen; Laaksonen, A.; Lehtinen, K. E. J.; S. Romakkaniemi

    2013-01-01

    In atmospheric modelling applications the aerosol particle size distribution is commonly represented by modal approach, in which particles in different size ranges are described with log-normal modes within predetermined size ranges. Such method includes numerical reallocation of particles from a mode to another for example during particle growth, leading to potentially artificial changes in the aerosol size distribution. In this study we analysed how this reallocation affects climatologicall...

  15. Reallocation in modal aerosol models: impacts on predicting aerosol radiative effects

    Science.gov (United States)

    Korhola, T.; Kokkola, H.; Korhonen, H.; Partanen, A.-I.; Laaksonen, A.; Lehtinen, K. E. J.; Romakkaniemi, S.

    2014-01-01

    Atmospheric models often represent the aerosol particle size distribution with a modal approach, in which particles are described with log-normal modes within predetermined size ranges. This approach reallocates particles numerically from one mode to another for example during particle growth, potentially leading to artificial changes in the aerosol size distribution. In this study we analysed how the modal reallocation affects climate-relevant variables: cloud droplet number concentration (CDNC), aerosol-cloud interaction parameter (ACI) and light extinction coefficient (qext). The ACI parameter gives the response of CDNC to a change in total aerosol number concentration. We compared these variables between a modal model (with and without reallocation routines) and a high resolution sectional model, which was considered a reference model. We analysed the relative differences in the chosen variables in four experiments designed to assess the influence of atmospheric aerosol processes. We find that limiting the allowed size ranges of the modes, and subsequent remapping of the distribution, leads almost always to an underestimation of cloud droplet number concentrations (by up to 100%) and an overestimation of light extinction (by up to 20%). On the other hand, the aerosol-cloud interaction parameter can be either over- or underestimated by the reallocating model, depending on the conditions. For example, in the case of atmospheric new particle formation events followed by rapid particle growth, the reallocation can cause on average a 10% overestimation of the ACI parameter. Thus it is shown that the reallocation affects the ability of a model to estimate aerosol climate effects accurately, and this should be taken into account when using and developing aerosol models.

  16. Reallocation in modal aerosol models: impacts on predicting aerosol radiative effects

    OpenAIRE

    Korhola, T.; H. Kokkola; Korhonen, H.; Partanen, A.-I.; Laaksonen, A.; Lehtinen, K. E. J.; S. Romakkaniemi

    2014-01-01

    Atmospheric models often represent the aerosol particle size distribution with a modal approach, in which particles are described with log-normal modes within predetermined size ranges. This approach reallocates particles numerically from one mode to another for example during particle growth, potentially leading to artificial changes in the aerosol size distribution. In this study we analysed how the modal reallocation affects climate-relevant variables: cloud droplet numbe...

  17. New trajectory driven aerosol and chemical process model: chemical and aerosol Lagrangian model (CALM)

    OpenAIRE

    Tunved, P.; D. G. Partridge; Korhonen, H.

    2010-01-01

    A new Chemical and Aerosol Lagrangian Model (CALM) have been developed and tested. The model incorporates all central aerosol dynamical processes, from nucleation, condensation, coagulation and deposition to cloud formation and in-cloud processing. The model is tested and evaluated against observations performed at the SMEAR II station located at Hyytiälä (61°51' N, 24°17' E) over a time period of two years, 2000–2001. The model shows good agreement with measurements thro...

  18. Climate implications of carbonaceous aerosols: An aerosol microphysical study using the GISS/MATRIX climate model

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Susanne E.; Menon, Surabi; Koch, Dorothy; Bond, Tami; Tsigaridis, Kostas

    2010-04-09

    Recently, attention has been drawn towards black carbon aerosols as a likely short-term climate warming mitigation candidate. However the global and regional impacts of the direct, cloud-indirect and semi-direct forcing effects are highly uncertain, due to the complex nature of aerosol evolution and its climate interactions. Black carbon is directly released as particle into the atmosphere, but then interacts with other gases and particles through condensation and coagulation processes leading to further aerosol growth, aging and internal mixing. A detailed aerosol microphysical scheme, MATRIX, embedded within the global GISS modelE includes the above processes that determine the lifecycle and climate impact of aerosols. This study presents a quantitative assessment of the impact of microphysical processes involving black carbon, such as emission size distributions and optical properties on aerosol cloud activation and radiative forcing. Our best estimate for net direct and indirect aerosol radiative forcing change is -0.56 W/m{sup 2} between 1750 and 2000. However, the direct and indirect aerosol effects are very sensitive to the black and organic carbon size distribution and consequential mixing state. The net radiative forcing change can vary between -0.32 to -0.75 W/m{sup 2} depending on these carbonaceous particle properties. Assuming that sulfates, nitrates and secondary organics form a coating shell around a black carbon core, rather than forming a uniformly mixed particles, changes the overall net radiative forcing from a negative to a positive number. Black carbon mitigation scenarios showed generally a benefit when mainly black carbon sources such as diesel emissions are reduced, reducing organic and black carbon sources such as bio-fuels, does not lead to reduced warming.

  19. Measuring Aerosol Optical Depth (AOD and Aerosol Profiles Simultaneously with a Camera Lidar

    Directory of Open Access Journals (Sweden)

    Barnes John

    2016-01-01

    Full Text Available CLidar or camera lidar is a simple, inexpensive technique to measure nighttime tropospheric aerosol profiles. Stars in the raw data images used in the CLidar analysis can also be used to calculate aerosol optical depth simultaneously. A single star can be used with the Langley method or multiple star pairs can be used to reduce the error. The estimated error from data taken under clear sky conditions at Mauna Loa Observatory is approximately +/- 0.01.

  20. Aerosol Indices Derived from MODIS Data for Indicating Aerosol-Induced Air Pollution

    Directory of Open Access Journals (Sweden)

    Junliang He

    2014-02-01

    Full Text Available Aerosol optical depth (AOD is a critical variable in estimating aerosol concentration in the atmosphere, evaluating severity of atmospheric pollution, and studying their impact on climate. With the assistance of the 6S radiative transfer model, we simulated apparent reflectancein relation to AOD in each Moderate Resolution Imaging Spectroradiometer (MODIS waveband in this study. The closeness of the relationship was used to identify the most and least sensitive MODIS wavebands. These two bands were then used to construct three aerosol indices (difference, ratio, and normalized difference for estimating AOD quickly and effectively. The three indices were correlated, respectively, with in situ measured AOD at the Aerosol Robotic NETwork (AERONET Lake Taihu, Beijing, and Xianghe stations. It is found that apparent reflectance of the blue waveband (band 3 is the most sensitive to AOD while the mid-infrared wavelength (band 7 is the least sensitive. The difference aerosol index is the most accurate in indicating aerosol-induced atmospheric pollution with a correlation coefficient of 0.585, 0.860, 0.685, and 0.333 at the Lake Taihu station, 0.721, 0.839, 0.795, and 0.629 at the Beijing station, and 0.778, 0.782, 0.837, and 0.643 at the Xianghe station in spring, summer, autumn and winter, respectively. It is concluded that the newly proposed difference aerosol index can be used effectively to study the level of aerosol-induced air pollution from MODIS satellite imagery with relative ease.