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Made available in DSpace on 2018-12-11T17:23:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-12 Every year, a dense smoke haze covers a large portion of South America originating from fires in the Amazon Basin and central parts of Brazil during the dry biomass burning season between August and October. Over a large portion of South America, the average aerosol optical depth at 550 nm exceeds 1.0 during the fire season, while the background value during the rainy season is below 0.2. Biomass burning aerosol particles increase scattering and absorption of the incident solar radiation. The regional-scale aerosol layer reduces the amount of solar energy reaching the surface, cools the near-surface air, and increases the diffuse radiation fraction over a large disturbed area of the Amazon rainforest. These factors affect the energy and CO2 fluxes at the surface. In this work, we applied a fully integrated atmospheric model to assess the impact of biomass burning aerosols in CO2 fluxes in the Amazon region during 2010. We address the effects of the attenuation of global solar radiation and the enhancement of the diffuse solar radiation flux inside the vegetation canopy. Our results indicate that biomass burning aerosols led to increases of about 27% in the gross primary productivity of Amazonia and 10% in plant respiration as well as a decline in soil respiration of 3 %. Consequently, in our model Amazonia became a net carbon sink; net ecosystem exchange during September 2010 dropped from C101 to 104 TgC when the aerosol effects are considered, mainly due to the aerosol diffuse radiation effect. For the forest biome, our results point to a dominance of the diffuse radiation effect on CO2 fluxes, reaching a balance of 50-50% between the diffuse and direct aerosol effects for high aerosol loads. For C3 grasses and savanna (cerrado), as expected, the contribution of the diffuse radiation effect is much lower, tending to zero with the increase in aerosol load. Taking all biomes together, our model shows the Amazon during the dry season, in the presence of high biomass burning aerosol loads, changing from being a source to being a sink of CO2 to the atmosphere. Faculdade de Ciências Universidade Estadual Paulista (UNESP) Centro de Meteorologia de Bauru (IPMet) Centro de Previsão de Tempo E Estudos Climáticos Instituto Nacional de Pesquisas Espaciais (INPE) Departamento de Ciências Atmosféricas do Institudo de Astronomia Geofísica e Ciências Atmosféricas Universidade de São Paulo (USP) College of Life and Environmental Sciences Geography University of Exeter Centre for Ecology and Hydrology (CEH) Universidade Federal de São Paulo (UNIFESP), Campus Diadema School of Geography Woodhouse Lane University of Leeds Departamento de Matemática Universidade Federal de Viçosa (UFV) Earth System Research Laboratory National Oceanic and Atmospheric Administration (NOAA) Global Monitoring Division Centro de Ciências do Sistema Terrestre Instituto Nacional de Pesquisas Espaciais (INPE) Instituto de Pesquisas Energéticas E Nucleares (IPEN) Comissão Nacional de Energia Nuclear (CNEN) Department of Ecology and Evolutionary Biology University of Arizona NASA Goddard Space Flight Center Global Modeling and Assimilation Office Universities Space Research Association/Goddard Earth Sciences Technology and Research (USRA/GESTAR) Faculdade de Ciências Universidade Estadual Paulista (UNESP)

We present the results of airborne measurements of carbon monoxide (CO) and aerosol particle number concentration (CN) made during the Balanço Atmosférico Regional de Carbono na Amazônia (BARCA) program. The primary goal of BARCA is to address the question of basin-scale sources and sinks of CO2 and other atmospheric carbon species, a central issue of the Large-scale Biosphere-Atmosphere (LBA) program. The experiment consisted of two aircraft campaigns during November–December 2008 (BARCA-A) and May–June 2009 (BARCA-B), which covered the altitude range from the surface up to about 4500 m, and spanned most of the Amazon Basin. Based on meteorological analysis and measurements of the tracer, SF6, we found that airmasses over the Amazon Basin during the late dry season (BARCA-A, November 2008) originated predominantly from the Southern Hemisphere, while during the late wet season (BARCA-B, May 2009) low-level airmasses were dominated by northern-hemispheric inflow and mid-tropospheric airmasses were of mixed origin. In BARCA-A we found strong influence of biomass burning emissions on the composition of the atmosphere over much of the Amazon Basin, with CO enhancements up to 300 ppb and CN concentrations approaching 10 000 cm−3; the highest values were in the southern part of the Basin at altitudes of 1–3 km. The ΔCN/ΔCO ratios were diagnostic for biomass burning emissions, and were lower in aged than in fresh smoke. Fresh emissions indicated CO/CO2 and CN/CO emission ratios in good agreement with previous work, but our results also highlight the need to consider the residual smoldering combustion that takes place after the active flaming phase of deforestation fires. During the late wet season, in contrast, there was little evidence for a significant presence of biomass smoke. Low CN concentrations (300–500 cm−3) prevailed basinwide, and CO mixing ratios were enhanced by only ~10 ppb above the mixing line between Northern and Southern Hemisphere air. There was no detectable trend in CO with distance from the coast, but there was a small enhancement of CO in the boundary layer suggesting diffuse biogenic sources from photochemical degradation of biogenic volatile organic compounds or direct biological emission. Simulations of CO distributions during BARCA-A using a range of models yielded general agreement in spatial distribution and confirm the important contribution from biomass burning emissions, but the models evidence some systematic quantitative differences compared to observed CO concentrations. These mismatches appear to be related to problems with the accuracy of the global background fields, the role of vertical transport and biomass smoke injection height, the choice of model resolution, and reliability and temporal resolution of the emissions data base.

A long term experiment was conducted in a pristine area in the Amazon forest, with continuous in situ measurements of aerosol optical properties between February 2008 and April 2011, comprising, to our knowledge, the longest database ever in Amazonia. Two types of aerosol particles, with significantly different optical properties were identified: coarse mode predominant biogenic aerosols in the wet season (January–June), naturally released by the forest metabolism, and fine mode dominated biomass burning aerosols in the dry season (July–December), transported from regional fires. Dry particle median scattering coefficients at the wavelength of 550 nm increased from 6.3 Mm−1 to 22 Mm−1, whereas absorption at 637 nm increased from 0.5 Mm−1 to 2.8 Mm−1 from wet to dry season. Most of the scattering in the dry season was attributed to the predominance of fine mode particles (40–80% of PM10 mass), while the enhanced absorption coefficients are attributed to the presence of light absorbing aerosols from biomass burning. As both scattering and absorption increased in the dry season, the single scattering albedo (SSA) did not show a significant seasonal variability, in average 0.86 ± 0.08 at 637 nm for dry particles. Measured particle optical properties were used to estimate the aerosol forcing efficiency at the top of the atmosphere. Results indicate that in this pristine forest site the radiative balance was dominated by the cloud cover, or, in other words, the aerosol indirect effect predominated over the direct effect, particularly in the wet season. Due to the high cloud fractions, the aerosol forcing efficiency was below −3.5 W m−2 in 70% of the wet season days and in 46% of the dry season days. These values are lower than the ones reported in the literature, which are based on remote sensing data. Besides the seasonal variation, the influence of external aerosol sources was observed occasionally. Periods of influence of the Manaus urban plume were detected, characterized by a consistent increase on particle scattering (factor 2.5) and absorption coefficients (factor 5). Episodes of biomass burning and mineral dust particles advection from Africa were observed between January and April, characterized by enhanced concentrations of fine mode (PM2.0), crustal elements (Al, Si, Ti, Fe) and potassium. During these episodes, median particle absorption coefficients increased by a factor of 2, whereas median SSA values decreased by 7%, in comparison to wet season conditions.

Isospin symmetry breaking has been investigated in mass A=67 mirror nuclei through the experimental determination of the E1 strengths of analog electromagnetic transitions. Lifetimes of excited states have been measured in (67)Se and (67)As with the centroid shift method. Through the comparison of the B(E1) strengths of the mirror 9/2(+)--7/2(-) transitions, the isovector and the isoscalar components of the electromagnetic transition amplitude were extracted. The presence of a large isoscalar component provides evidence for coherent contributions to isospin mixing, probably involving the isovector giant monopole resonance.

The slowing down of heavy ions in matter is still not well understood especially at low energies (

This work focus on the electromagnetic decay properties of the heaviest known mirror pair 67As and 67Se, produced in the fusion evaporation reaction 32S+40Ca, with a E = 90 MeV beam provided by the ATLAS accelerator at Argonne National Laboratory. The high selectivity required to investigate these proton‐rich nuclei was achieved with the concurrent employment of Gammasphere, Neutron‐Shell, and Microball. The full array allowed to obtain the level scheme of the 67Se nucleus up to 5.56 MeV, and 5 new transitions were assigned to the known 67As level‐scheme. The level spin and parities were assigned using the ADO analysis and symmetry arguments.

Conference on Frontiers in Nuclear Structure, Astrophysics, and Reactions -- SEP 10-14, 2007 -- Crete, GREECE, WOS: 000256223700023, Medium and high spin states of the nuclei close to the N=50 shell closure are investigated Using deep inelastic and multi-nucleon transfer reactions. New excited states of the nuclei Ga-81, Ge-82 and As-83 at N=50 shell closure have been identified by means of the Se-82+U-238 reaction. Gamma rays have been acquired using the PRISMA-CLARA setup of the Laboratori Nazionali di Legnaro, Italy (LNL)., NCSR, Univ Jyvaskyla, Natl Tech Univ Athens, Greek Minist Educ, U.S. Department of Energy [DE-AC05-00OR22725], I wish to thank the staff of HRIBF for their dedication in the production of RIBs. This talk is based on work done in collaboration with various individuals: C. Baktash, J. Batchelder, J.R. Beene, B. Fuentes, J. Gomez del Campo, C.J. Gross, M.L. Halbert, P.A. Hausladen, Y. Larochelle, J. F.Liang, P.E. Mueller, E. Padilla-Rodal, D.C. Radford, D. Shapira, D.W. Stracener, J. P. Urrego, R.L. Varner and C.-H. Yu. Oak Ridge National Laboratory is managed by UT-Battelle, LLC for the U.S. Department of Energy under Contract No. DE-AC05-00OR22725.

In this work we present the results of in beam tests of the adaptations of the Saci‐Perere spectrometer (IFUSP) for nuclear reaction mechanism studies.