35 resultados para Mass balance in the Earth
em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP)
Resumo:
Neutrino telescopes with cubic kilometer volumes have the potential to discover new particles. Among them are next to lightest supersymmetric (NLSPs) and next to lightest Kaluza-Klein (NLKPs) particles. Two NLSPs or NLKPs will transverse the detector simultaneously producing parallel charged tracks. The track separation inside the detector can be a few hundred meters. As these particles might propagate a few thousand kilometers before reaching the detector, multiple scattering could enhance the pair separation at the detector. We find that the multiple scattering will alter the separation distribution enough to increase the number of NLKP pairs separated by more than 100 meters (a reasonable experimental cut) by up to 46% depending on the NLKP mass. Vertical upcoming NLSPs will have their separation increased by 24% due to multiple scattering.
Resumo:
Role of reactive oxygen species (ROS)/nitric oxide (NO) balance and renin-angiotensin system in mediating cardiac hypertrophy in hyperthyroidism was evaluated in an in vivo and in vitro experimental model. Male Wistar rats were divided into four groups: control, thyroid hormone, vitamin E (or Trolox, its hydrosoluble analogue), thyroid hormone + vitamin E. Angiotensin II receptor (AT1/AT2) gene expression, immunocontent of AT1/AT2 receptors, angiotensinogen, NADPH oxidase (Nox2), and nitric oxide synthase isoforms, as well as ROS concentration (hydrogen peroxide and superoxide anion) were quantified in myocardium. Thyroid hormone increased ROS and NO metabolites, iNOS, nNOS and eNOS isoforms and it was accompanied by cardiac hypertrophy. AT1/AT2 expression and the immunocontent of angiotensinogen and Nox2 were enhanced by thyroid hormone. Antioxidants reduced ROS levels, Nox2, AT1/AT2, NOS isoforms and cardiac hypertrophy. In conclusion, ROS/NO balance may play a role in the control of thyroid hormone-induced cardiac hypertrophy mediated by renin-angiotensin system. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
Resumo:
Recent experiments have shown that the multimode approach for describing the fission process is compatible with the observed results. Asystematic analysis of the parameters obtained by fitting the fission-fragment mass distribution to the spontaneous and low-energy data has shown that the values for those parameters present a smooth dependence upon the nuclear mass number. In this work, a new methodology is introduced for studying fragment mass distributions through the multimode approach. It is shown that for fission induced by energetic probes (E > 30 MeV) the mass distribution of the fissioning nuclei produced during the intranuclear cascade and evaporation processes must be considered in order to have a realistic description of the fission process. The method is applied to study (208)Pb, (238)U, (239)Np and (241)Am fission induced by protons or photons.
Resumo:
On-line leak detection is a main concern for the safe operation of pipelines. Acoustic and mass balance are the most important and extensively applied technologies in field problems. The objective of this work is to compare these leak detection methods with respect to a given reference situation, i.e., the same pipeline and monitoring signals acquired at the inlet and outlet ends. Experimental tests were conducted in a 749 m long laboratory pipeline transporting water as the working fluid. The instrumentation included pressure transducers and electromagnetic flowmeters. Leaks were simulated by opening solenoid valves placed at known positions and previously calibrated to produce known average leak flow rates. Results have clearly shown the limitations and advantages of each method. It is also quite clear that acoustics and mass balance technologies are, in fact, complementary. In general, an acoustic leak detection system sends out an alarm more rapidly and locates the leak more precisely, provided that the rupture of the pipeline occurs abruptly enough. On the other hand, a mass balance leak detection method is capable of quantifying the leak flow rate very accurately and of detecting progressive leaks.
Resumo:
An important feature of Axelrod`s model for culture dissemination or social influence is the emergence of many multicultural absorbing states, despite the fact that the local rules that specify the agents interactions are explicitly designed to decrease the cultural differences between agents. Here we re-examine the problem of introducing an external, global interaction-the mass media-in the rules of Axelrod`s model: in addition to their nearest neighbors, each agent has a certain probability p to interact with a virtual neighbor whose cultural features are fixed from the outset. Most surprisingly, this apparently homogenizing effect actually increases the cultural diversity of the population. We show that, contrary to previous claims in the literature, even a vanishingly small value of p is sufficient to destabilize the homogeneous regime for very large lattice sizes.
Resumo:
The influence of impeller type and stirring frequency on the performance of a mechanically stirred anaerobic sequencing batch reactor containing immobilized biomass on an inert support (AnSBBR - Anaerobic Sequencing Batch Biofilm Reactor) was evaluated. The biomass was immobilized on polyurethane foam cubes placed in a stainless-steel basket inside a glass cylinder. Each 8-h batch run consisted of three stages: feed (10 min), reaction (460 min) and discharge (10 min) at 30 degrees C. Experiments were performed with four impeller types, i.e., helical, flat-blade, inclined-blade and curved-blade turbines, at stirring frequencies ranging from 100 to 1100 rpm. Synthetic wastewater was used in all experiments with an organic-matter concentration of 530 +/- 37 mg/L measured as chemical oxygen demand (COD). The reactor achieved an organic-matter removal efficiency of around 87% under all investigated conditions. Analysis of the four impeller types and the investigated stirring frequencies showed that mass transfer in the liquid phase was affected not only by the applied stirring frequency but also by the agitation mode imposed by each impeller type. The best reactor performance at all stirring frequencies was obtained when agitation was provided by the flat-blade turbine impeller. (C) 2010 Elsevier Ltd. All rights reserved.
Resumo:
Linear alkylbenzene sulfonate (LAS) is an anionic surfactant widely used to manufacture detergents and found in domestic and industrial wastewater. LAS removal was evaluated in a horizontal anaerobic immobilized biomass reactor. The system was filled with polyurethane foam and inoculated with sludge that was withdrawn from an up flow anaerobic sludge blanket reactor that is used to treat swine wastewater. The reactor was fed with easily degradable substrates and a solution of commercial LAS for 313 days. The hydraulic retention time applied was 12 h. The system was initially operated without detergent and resulted to 94% reduction of demand. The mass balance in the system indicated that the LAS removal efficiency was 45% after 180 days. From the 109th day to the 254th day, a removal efficiency of 32% was observed. The removal of LAS was approximately 40% when 1500 mg of LAS were applied in the absence of co-substrates suggesting that the LAS molecules were used selectively. Microscopic analyses of the biofilm revealed diverse microbial morphologies and denaturing gradient gel electrophoresis profiling showed variations in the total bacteria and sulfate-reducing bacteria populations. 16S rRNA sequencing and phylogenetic analyses demonstrated that members of the order Clostridiales were the major components of the bacterial community in the last step of the reactor operation. (c) 2009 Elsevier Ltd. All rights reserved.
Resumo:
A modeling study was completed to develop a methodology that combines the sequencing and finite difference methods for the simulation of a heterogeneous model of a tubular reactor applied in the treatment of wastewater. The system included a liquid phase (convection diffusion transport) and a solid phase (diffusion reaction) that was obtained by completing a mass balance in the reactor and in the particle, respectively. The model was solved using a pilot-scale horizontal-flow anaerobic immobilized biomass (HAIB) reactor to treat domestic sewage, with the concentration results compared with the experimental data. A comparison of the behavior of the liquid phase concentration profile and the experimental results indicated that both the numerical methods offer a good description of the behavior of the concentration along the reactor. The advantage of the sequencing method over the finite difference method is that it is easier to apply and requires less computational time to model the dynamic simulation of outlet response of HAIB.
Resumo:
Some aerosol particles, known as ice nuclei, can initiate ice formation in clouds, thereby influencing precipitation, cloud dynamics and the amount of incoming and outgoing solar radiation. In the absence of biomass burning, aerosol mass concentrations in the Amazon basin are low(1). Tropical forests emit primary biological particles directly into the atmosphere; secondary organic aerosols form from the emission and oxidation of biogenic gases(2). In addition, particles derived from biomass burning in central Africa, marine aerosols, and windblown dust from North Africa(3-5) often reach the central part of the Amazon basin during the wet season. The contribution of these aerosol sources to ice nucleation in the region is uncertain. Here we present observations of the concentration and elemental composition of ice nuclei in the Amazon basin during the wet season. Using transmission electron microscopy combined with energy-dispersive X-ray spectroscopy, we show that ice nuclei are primarily composed of carbonaceous material and dust. We show that biological particles dominate the carbonaceous fraction, whereas import of Saharan dust explains the intermittent appearance of dust-containing nuclei. We conclude that ice-nucleus concentration and abundance can be explained almost entirely by local emissions of biological particles supplemented by import of Saharan dust. Using a simple model, we tentatively suggest that the contribution of local biological particles to ice nucleation is increased at higher atmospheric temperatures, whereas the contribution of dust particles is increased at lower temperatures.
Resumo:
In this work we study the spontaneous breaking of superconformal and gauge invariances in the Abelian N = 1,2 three-dimensional supersymmetric Chern-Simons-matter (SCSM) theories in a large N flavor limit. We compute the Kahlerian effective superpotential at subleading order in 1/N and show that the Coleman-Weinberg mechanism is responsible for the dynamical generation of a mass scale in the N = 1 model. This effect appears due to two-loop diagrams that are logarithmic divergent. We also show that the Coleman-Weinberg mechanism fails when we lift from the N = 1 to the N = 2 SCSM model. (C) 2010 Elsevier B.V All rights reserved.
Resumo:
Surface roughness is an important geomorphological variable which has been used in the Earth and planetary sciences to infer material properties, current/past processes, and the time elapsed since formation. No single definition exists; however, within the context of geomorphometry, we use surface roughness as an expression of the variability of a topographic surface at a given scale, where the scale of analysis is determined by the size of the landforms or geomorphic features of interest. Six techniques for the calculation of surface roughness were selected for an assessment of the parameter`s behavior at different spatial scales and data-set resolutions. Area ratio operated independently of scale, providing consistent results across spatial resolutions. Vector dispersion produced results with increasing roughness and homogenization of terrain at coarser resolutions and larger window sizes. Standard deviation of residual topography highlighted local features and did not detect regional relief. Standard deviation of elevation correctly identified breaks of slope and was good at detecting regional relief. Standard deviation of slope (SD(slope)) also correctly identified smooth sloping areas and breaks of slope, providing the best results for geomorphological analysis. Standard deviation of profile curvature identified the breaks of slope, although not as strongly as SD(slope), and it is sensitive to noise and spurious data. In general, SD(slope) offered good performance at a variety of scales, while the simplicity of calculation is perhaps its single greatest benefit.
Resumo:
Submicron atmospheric particles in the Amazon Basin were characterized by a high-resolution aerosol mass spectrometer during the wet season of 2008. Patterns in the mass spectra closely resembled those of secondary-organic-aerosol (SOA) particles formed in environmental chambers from biogenic precursor gases. In contrast, mass spectral indicators of primary biological aerosol particles (PBAPs) were insignificant, suggesting that PBAPs contributed negligibly to the submicron fraction of particles during the period of study. For 40% of the measurement periods, the mass spectra indicate that in-Basin biogenic SOA production was the dominant source of the submicron mass fraction, contrasted to other periods (30%) during which out-of-Basin organic-carbon sources were significant on top of the baseline in-Basin processes. The in-Basin periods had an average organic-particle loading of 0.6 mu g m(-3) and an average elemental oxygen-to-carbon (O:C) ratio of 0.42, compared to 0.9 mu g m(-3) and 0.49, respectively, during periods of out-of-Basin influence. On the basis of the data, we conclude that most of the organic material composing submicron particles over the Basin derived from biogenic SOA production, a finding that is consistent with microscopy observations made in a concurrent study. This source was augmented during some periods by aged organic material delivered by long-range transport. Citation: Chen, Q., et al. (2009), Mass spectral characterization of submicron biogenic organic particles in the Amazon Basin, Geophys. Res. Lett., 36, L20806, doi: 10.1029/2009GL039880.
Resumo:
Association studies between ADIPOR1 genetic variants and predisposition to type 2 diabetes (DM2) have provided contradictory results. We determined if two single nucleotide polymorphisms (SNP c.-8503G>A and SNP c.10225C>G) in regulatory regions of ADIPOR1 in 567 Brazilian individuals of European (EA; N = 443) or African (AfA; N = 124) ancestry from rural (quilombo remnants; N = 439) and urban (N = 567) areas. We detected a significant effect of ethnicity on the distribution of the allelic frequencies of both SNPs in these populations (EA: -8503A = 0.27; AfA: -8503A = 0.16; P = 0.001 and EA: 10225G = 0.35; AfA: 10225G = 0.51; P < 0.001). Neither of the polymorphisms were associated with DM2 in the case-control study in EA (SNP c.-8503G>A: DM2 group -8503A = 0.26; control group -8503A = 0.30; P = 0.14/SNP 10225C>G: DM2 group 10225G = 0.37; control group 10225G = 0.32; P = 0.40) and AfA populations (SNP c.-8503G>A: DM2 group -8503A = 0.16; control group -8503A = 0.15; P = 0.34/SNP 10225C>G: DM2 group 10225G = 0.51; control group 10225G = 0.52; P = 0.50). Similarly, none of the polymorphisms were associated with metabolic/anthropometric risk factors for DM2 in any of the three populations, except for HDL cholesterol, which was significantly higher in AfA heterozygotes (GC = 53.75 ± 17.26 mg/dL) than in homozygotes. We conclude that ADIPOR1 polymorphisms are unlikely to be major risk factors for DM2 or for metabolic/anthropometric measurements that represent risk factors for DM2 in populations of European and African ancestries.
Resumo:
The aging process is frequently characterized by an involuntary loss of muscle (sarcopenia) and bone (osteoporosis) mass. Both chronic diseases are associated with decreased metabolic rate, increased risk of falls fracture, and, as a result, increased morbidity and loss of independence in the elderly. The quality and quantity of protein intake affects bone and muscle mass in several ways and there is evidence that increased essential amino acid or protein availability can enhance muscle protein synthesis and anabolism, as well as improve bone homeostasis in older subjects. A thorough evaluation of renal function is important, since renal function decreases with age. Finally, protein and calcium intake should be considered in the prevention or treatment of the chronic diseases osteoporosis and sarcopenia
Resumo:
Context. It is not known how many globular clusters may remain undetected towards the Galactic bulge. Aims. One of the aims of the VISTA Variables in the Via Lactea (VVV) Survey is to accurately measure the physical parameters of the known globular clusters in the inner regions of the Milky Way and search for new ones, hidden in regions of large extinction. Methods. From deep near-infrared images, we derive deep JHK(S)-band photometry of a region surrounding the known globular cluster UKS 1 and reveal a new low-mass globular cluster candidate that we name VVV CL001. Results. We use the horizontal-branch red clump to measure E(B-V) similar to 2.2 mag, (m - M)(0) = 16.01 mag, and D = 15.9 kpc for the globular cluster UKS 1. On the basis of near-infrared colour-magnitude diagrams, we also find that VVV CL001 has E(B-V) similar to 2.0, and that it is at least as metal-poor as UKS 1, although its distance remains uncertain. Conclusions. Our finding confirms the previous projection that the central region of the Milky Way harbours more globular clusters. VVV CL001 and UKS 1 are good candidates for a physical cluster binary, but follow-up observations are needed to decide if they are located at the same distance and have similar radial velocities.