Gauge invariance of the background average effective action

Using the background field method for the functional renormalization group approach in the case of a generic gauge theory, we study the background field symmetry and gauge dependence of the background average effective action, when the regulator action depends on external fields. The final result is that the symmetry of the average effective action can be maintained for a wide class of regulator functions, but in all cases the dependence of the gauge fixing remains on-shell. The Yang-Mills theory is considered as the main particular example.Comment: Fits the version accepted in EPJ

Aerosol number fluxes over the Amazon rain forest during the wet season

Number fluxes of particles with diameter larger than 10 nm were measured with the eddy covariance method over the Amazon rain forest during the wet season as part of the LBA (The Large Scale Biosphere Atmosphere Experiment in Amazonia) campaign 2008. The primary goal was to investigate whether sources or sinks dominate the aerosol number flux in the tropical rain forest-atmosphere system. During the measurement campaign, from 12 March to 18 May, 60% of the particle fluxes pointed downward, which is a similar fraction to what has been observed over boreal forests. The net deposition flux prevailed even in the absolute cleanest atmospheric conditions during the campaign and therefore cannot be explained only by deposition of anthropogenic particles. The particle transfer velocity v(t) increased with increasing friction velocity and the relation is described by the equation v(t) = 2.4x10(-3)xu(*) where u(*) is the friction velocity. Upward particle fluxes often appeared in the morning hours and seem to a large extent to be an effect of entrainment fluxes into a growing mixed layer rather than primary aerosol emission. In general, the number source of primary aerosol particles within the footprint area of the measurements was small, possibly because the measured particle number fluxes reflect mostly particles less than approximately 200 nm. This is an indication that the contribution of primary biogenic aerosol particles to the aerosol population in the Amazon boundary layer may be low in terms of number concentrations. However, the possibility of horizontal variations in primary aerosol emission over the Amazon rain forest cannot be ruled out.National Institute for Research in the Amazon (INPA)LBA infrastructure teamCNPq/MCT Millennium Institute ProgramFAPES

A comparison of dry and wet season aerosol number fluxes over the Amazon rain forest

Vertical number fluxes of aerosol particles and vertical fluxes of CO(2) were measured with the eddy covariance method at the top of a 53 m high tower in the Amazon rain forest as part of the LBA (The Large Scale Biosphere Atmosphere Experiment in Amazonia) experiment. The observed aerosol number fluxes included particles with sizes down to 10 nm in diameter. The measurements were carried out during the wet and dry season in 2008. In this study focus is on the dry season aerosol fluxes, with significant influence from biomass burning, and these are compared with aerosol fluxes measured during the wet season. Net particle deposition fluxes dominated in daytime in both seasons and the deposition flux was considerably larger in the dry season due to the much higher dry season particle concentration. The particle transfer velocity increased linearly with increasing friction velocity in both seasons. The difference in transfer velocity between the two seasons was small, indicating that the seasonal change in aerosol number size distribution is not enough for causing any significant change in deposition velocity. In general, particle transfer velocities in this study are low compared to studies over boreal forests. The reasons are probably the high percentage of accumulation mode particles and the low percentage of nucleation mode particles in the Amazon boundary layer, both in the dry and wet season, and low wind speeds in the tropics compared to the midlatitudes. In the dry season, nocturnal particle fluxes behaved very similar to the nocturnal CO(2) fluxes. Throughout the night, the measured particle flux at the top of the tower was close to zero, but early in the morning there was an upward particle flux peak that is not likely a result of entrainment or local pollution. It is possible that these morning upward particle fluxes are associated with emission of primary biogenic particles from the rain forest. Emitted particles may be stored within the canopy during stable conditions at nighttime, similarly to CO(2), and being released from the canopy when conditions become more turbulent in the morning.National Institute for Research in the Amazon (INPA)LBACNPq/MCTFAPES

Robust relations between CCN and the vertical evolution of cloud drop size distribution in deep convective clouds

In-situ measurements in convective clouds (up to the freezing level) over the Amazon basin show that smoke from deforestation fires prevents clouds from precipitating until they acquire a vertical development of at least 4 km, compared to only 1-2 km in clean clouds. The average cloud depth required for the onset of warm rain increased by similar to 350 m for each additional 100 cloud condensation nuclei per cm(3) at a super-saturation of 0.5% (CCN0.5%). In polluted clouds, the diameter of modal liquid water content grows much slower with cloud depth (at least by a factor of similar to 2), due to the large number of droplets that compete for available water and to the suppressed coalescence processes. Contrary to what other studies have suggested, we did not observe this effect to reach saturation at 3000 or more accumulation mode particles per cm(3). The CCN0.5% concentration was found to be a very good predictor for the cloud depth required for the onset of warm precipitation and other microphysical factors, leaving only a secondary role for the updraft velocities in determining the cloud drop size distributions. The effective radius of the cloud droplets (r(e)) was found to be a quite robust parameter for a given environment and cloud depth, showing only a small effect of partial droplet evaporation from the cloud's mixing with its drier environment. This supports one of the basic assumptions of satellite analysis of cloud microphysical processes: the ability to look at different cloud top heights in the same region and regard their r(e) as if they had been measured inside one well developed cloud. The dependence of r(e) on the adiabatic fraction decreased higher in the clouds, especially for cleaner conditions, and disappeared at r(e)>=similar to 10 mu m. We propose that droplet coalescence, which is at its peak when warm rain is formed in the cloud at r(e)=similar to 10 mu m, continues to be significant during the cloud's mixing with the entrained air, cancelling out the decrease in r(e) due to evaporation

Aerosol and precipitation chemistry measurements in a remote site in Central Amazonia: the role of biogenic contribution

In this analysis a 3.5 years data set of aerosol and precipitation chemistry, obtained in a remote site in Central Amazonia (Balbina, (1A degrees 55' S, 59A degrees 29' W, 174 m a.s.l.), about 200 km north of Manaus) is discussed. Aerosols were sampled using stacked filter units (SFU), which separate fine (d < 2.5 mu m) and coarse mode (2.5 mu m < d < 10.0 mu m) aerosol particles. Filters were analyzed for particulate mass (PM), Equivalent Black Carbon (BCE) and elemental composition by Particle Induced X-Ray Emission (PIXE). Rainwater samples were collected using a wet-only sampler and samples were analyzed for pH and ionic composition, which was determined using ionic chromatography (IC). Natural sources dominated the aerosol mass during the wet season, when it was predominantly of natural biogenic origin mostly in the coarse mode, which comprised up to 81% of PM10. Biogenic aerosol from both primary emissions and secondary organic aerosol dominates the fine mode in the wet season, with very low concentrations (average 2.2 mu g m(-3)). Soil dust was responsible for a minor fraction of the aerosol mass (less than 17%). Sudden increases in the concentration of elements as Al, Ti and Fe were also observed, both in fine and coarse mode (mostly during the April-may months), which we attribute to episodes of Saharan dust transport. During the dry periods, a significant contribution to the fine aerosols loading was observed, due to the large-scale transport of smoke from biomass burning in other portions of the Amazon basin. This contribution is associated with the enhancement of the concentration of S, K, Zn and BCE. Chlorine, which is commonly associated to sea salt and also to biomass burning emissions, presented higher concentration not only during the dry season but also for the April-June months, due to the establishment of more favorable meteorological conditions to the transport of Atlantic air masses to Central Amazonia. The chemical composition of rainwater was similar to those ones observed in other remote sites in tropical forests. The volume-weighted mean (VWM) pH was 4.90. The most important contribution to acidity was from weak organic acids. The organic acidity was predominantly associated with the presence of acetic acid instead of formic acid, which is more often observed in pristine tropical areas. Wet deposition rates for major species did not differ significantly between dry and wet season, except for NH4+, citrate and acetate, which had smaller deposition rates during dry season. While biomass burning emissions were clearly identified in the aerosol component, it did not present a clear signature in rainwater. The biogenic component and the long-range transport of sea salt were observed both in aerosols and rainwater composition. The results shown here indicate that in Central Amazonia it is still possible to observe quite pristine atmospheric conditions, relatively free of anthropogenic influences.FAPESPFAPESPCNPqCNP

Comparing properties of natural biogenic with biomass burning particles in Amazonia.

The Large Scale Biosphere Atmosphere Experiment in\ud Amazonia (LBA) is a long-term (20 years) research effort\ud aimed at the understanding of the functioning of the\ud Amazonian ecosystem. The strong biosphere-atmosphere\ud interaction is a key component of the ecosystem functioning.\ud Two aerosol components are the most visible: The natural\ud biogenic emissions of particles and VOCs, and the biomass\ud burning emissions.\ud Two aerosol and trace gases monitoring stations were\ud operated for 4 years in Manaus and Porto Velho, two very\ud distinct sites, with different land use change. Manaus is a very\ud clean and pristine site and Porto Velho is representative of\ud heavy land use change in Amazonia. Aerosol composition,\ud optical properties, size distribution, vertical profiling and\ud optical depth were measured from 2008 to 2012. Aerosol\ud radiative forcing was calculated over large areas. It was\ud observed that the natural biogenic aerosol has significant\ud absorption properties. Organic aerosol dominates the aerosol\ud mass with 80 to 95%. Light scattering and light absorption\ud shows an increase by factor of 10 from Manaus to Porto\ud Velho. Very few new particle formation events were\ud observed. Strong links between aerosols and VOC emissions\ud were observed. Aerosol radiative forcing in Rondonia shows\ud a high -15 watts/m² during the dry season of 2010, showing\ud the large impacts of aerosol loading in the Amazonian\ud ecosystem. The increase in diffuse radiation changes the\ud forest carbon uptake by 20 to 35%, a large increase in this\ud important ecosystem

AIDS related malignancies in Brazil

There have been relatively few studies of HIV-related malignancies in Brazil. Universal access to antiretroviral drugs in Brazil has changed both the mortality and morbidity rates of AIDS. Nevertheless, there is also extreme poverty in both urban and rural areas and complications of prolonged immune suppression such as mycobacterial and malignant diseases have put a significant strain on the country’s healthcare system. This brief review outlines the existing data regarding AIDS related malignancies in the largest Latin American country

Crosssectional study to evaluate factors associated with adherence to antiretroviral therapy by Brazilian HIV-infected patients.

ABSTRACT Antiretroviral therapy success is highly dependent on the ability of the patient to fully adhere to the prescribed treatment regimen. We present the results of a cross-sectional study that evaluates the predictive value of a self-administered questionnaire of adherence to antiretroviral (ARV) therapy. Study participants were interviewed using a 36-item Patient Medication Adherence Questionnaire (PMAQ) designed to assess knowledge about ARV therapy, motivation to adhere to treatment, and behavioral skills. Plasma HIV-1 RNA levels were correlated with the results obtained from the PMAQ. Of the 182 study participants, 82 (45%) were receiving their initial ARV regimen. Of the remaining patients, 39 (21%) and 61 (34%) were on a second or additional ARV regimen, respectively. An undetectable viral load was documented in 47/62 (76%) patients on their first regimen who reported missing medication on less than 4 days in the last 3 months. The PMAQ had a higher predictive value of plasma viral suppression for patients in the initial regimen than for patients in salvage therapy. The overall predictive value of the PMAQ to identify adherence was 74%, and 59% for nonadherence, with an overall efficacy of 64%. Of the 74 patients (45%) who did not understand the concept of antiretroviral therapy, 80% were failing or had previously failed the ARV treatment. Of 35 patients with doubts about their HIV status or skeptical of the benefits of ARV therapy, 29 (84%) were nonadherent. Despite the positive predictive value of PMAQ in identifying adherence, self-reported adherence is not a sufficiently precise predictor of treatment success to substitute for viral load monitoring. On the other hand, the use of such an instrument to identify factors associated with nonadherence provides an excellent opportunity to apply early intervention designed to specifically address factors that might be contributing to the lack of adherence prior to regimen failure