Sources of uncertainties in modelling black carbon at the global scale

Our understanding of the global black carbon (BC) cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and those due to the uncertainties in the definition and quantification of the observations, which propagate through to both the emission inventories, and the measurements used for the model evaluation. The schemes for the atmospheric processing of black carbon that have been tested with the model are (i) a simple approach considering BC as bulk aerosol and a simple treatment of the removal with fixed 70% of in-cloud black carbon concentrations scavenged by clouds and removed when rain is present and (ii) a more complete description of microphysical ageing within an aerosol dynamics model, where removal is coupled to the microphysical properties of the aerosol, which results in a global average of 40% in-cloud black carbon that is scavenged in clouds and subsequently removed by rain, thus resulting in a longer atmospheric lifetime. This difference is reflected in comparisons between both sets of modelled results and the measurements. Close to the sources, both anthropogenic and vegetation fire source regions, the model results do not differ significantly, indicating that the emissions are the prevailing mechanism determining the concentrations and the choice of the aerosol scheme does not influence the levels. In more remote areas such as oceanic and polar regions the differences can be orders of magnitude, due to the differences between the two schemes. The more complete description reproduces the seasonal trend of the black carbon observations in those areas, although not always the magnitude of the signal, while the more simplified approach underestimates black carbon concentrations by orders of magnitude. The sensitivity to wet scavenging has been tested by varying in-cloud and below-cloud removal. BC lifetime increases by 10% when large scale and convective scale precipitation removal efficiency are reduced by 30%, while the variation is very small when below-cloud scavenging is zero. Since the emission inventories are representative of elemental carbon-like substance, the model output should be compared to elemental carbon measurements and if known, the ratio of black carbon to elemental carbon mass should be taken into account when the model is compared with black carbon observation

Spin-orbit-enhanced Wigner localization in quantum dots

We investigate quantum dots with Rashba spin-orbit coupling in the strongly-correlated regime. We show that the presence of the Rashba interaction enhances the Wigner localization in these systems, making it achievable for higher densities than those at which it is observed in Rashba-free quantum dots. Recurring shapes in the pair-correlated densities of the yrast spectrum, which might be associated with rotational and vibrational modes, are also reported.Comment: 5 pages, 4 figure

Organic matter in forest arrangements within the Crop-Livestock-Forest Integration System in Mato Grosso State.

In Mato Grosso State, the main objectives of this integration are the shading provided to the animals, the improvement in the pastures? fertility, and the availability of wood for use at the property

Soil P, K, and Al contents in a Crop-Livestock-Forest integration system in Mato Grosso State.

The objective of this study was to evaluate the soil P, K, and Al contents in a CLFi system established in Nova Canaã do Norte-MT, Brazil

The third year of an integrated crop-livestock-forest system at the AmazonBiome: soybean

The soybean has been widely used within integrated systems, especially in the first stages of development of forestry species when competition for resources such as light, water and nutrients are lesser. Being able to timely cultivate legumes within an integrated system is of ultimate importance since soil characteristics, both physical and chemical, are concurrently improved with income generation

Brief Communication: A new testing field for debris flow warning systems

Abstract. A permanent field installation for the systematic test of debris flow warning systems and algorithms has been equipped on the eastern Italian Alps. The installation was also designed to produce didactic videos and it may host informative visits. The populace education is essential and should be envisaged in planning any research on hazard mitigation interventions: this new installation responds to this requirement and offers an example of integration between technical and informative needs. The occurrence of a debris flow in 2014 allowed the first tests of a new warning system under development and to record an informative video on its performances. This paper will provide a description of the installation and an account of the first technical and informative results obtained

Estrutura pré- e pós-corte de capim Marandu em função da face de exposição ao sol e distância do renque em sistema silvipastoril

A avaliação estrutural do dossel é uma maneira de garantir o entendimento dos mecanismos que governam o acúmulo de forragem em sistemas de produção. O sombreamento total ou parcial de forrageiras produzidas em sistemas Silvipastoril está atrelado a uma discussão fun damental para o entendimento das respostas estruturais de gramíneas tropicais. O objetivo foi avaliar o comportamento e as características morfológicas e estruturais do capim Marandu (Brachiaria brizantha cv. Marandu), em função da face de exposição (norte e sul) e distância (3, 6, 10 e 15 metros) das arvores no sistema Silvipastoril. O delineamento foi inteiramente casualizado, em parcela subdividida (64 m²), com quatro repetições. Dosséis manejados no sistema Silvipastoril, tanto na linha quanto na face, possuem valores médios de índice de interceptação luminosa (IL), índice de área foliar (IAF) e alturas semelhantes, no pré- e no pós-corte. A altura em pós-corte foi de 12,75 cm, muito próxima da meta de resíduo (15 cm), e correspondeu a um IAF médio de 2,75 e ângulo da folhagem (ANG) de 49,5º e interceptação luminosa (IL) de 75,94%. No pré-corte os ângulos foliares corresponderam a um valor médio de 40,2º. A altura foi em média, 28 cm com IL de 95,4%. As características estruturais do pasto de Brachiaria brizantha cv. Marandu em sistema silvipastoril não foi influenciado pela face de exposição e distância do renque, enquanto as árvores têm até 9 metros de altura

Measurement of Dielectric Suppression of Bremsstrahlung

In 1953, Ter-Mikaelian predicted that the bremsstrahlung of low energy photons in a medium is suppressed because of interactions between the produced photon and the electrons in the medium. This suppression occurs because the emission takes place over on a long distance scale, allowing for destructive interference between different instantaneous photon emission amplitudes. We present here measurements of bremsstrahlung cross sections of 200 keV to 20 MeV photons produced by 8 and 25 GeV electrons in carbon and gold targets. Our data shows that dielectric suppression occurs at the predicted level, reducing the cross section up to 75 percent in our data.Comment: 11 pages, format is postscript file, gzip-ed, uuencode-e