Heavy λ semileptonic decay: A QCD sum rule approach

In this work we calculate the form factors of the Lambda(c) and Lambda(b) semileptonic decay using the QCD sum rules approach. We found that the form factors sum rules are more stable than the respective mass sum rules, and we get a decay rate for Lambda(c) compatible with experiment.

Radiative Omega(-)->Xi(-)gamma decay and physics beyond the standard model

We investigate the impact of new physics beyond the standard model to the s → dγ process, which is responsible for the short-distance contribution to the radiative decay Ω-Ξ-γ. We study three representative extensions of the standard model: namely, a one-family technicolor model, a two-Higgs-doublet model, and a model containing scalar leptoquarks. When constraints arising from the observed b→sγ transition and the upper limit on D0-D̄0 mixing are taken into account, we find no significant contributions of new physics to the s→dy process.

A 3-D finite element study of the influence of crown-implant ratio on stress distribution

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Utility of inline milk fat and protein ratio to diagnose subclinical ketosis and to assign propylene glycol treatment in lactating dairy cows

The objective was to identify a fat-to-protein ratio (FPR) cut-off to diagnose subclinical ketosis (SCK) and to evaluate the effect of propylene glycol (PPG) treatment of cows with high FPR. The optimized cut-off was > 1.42; sensitivity (Se) = 92%; specificity (Sp) = 65%. A cut-off > 1.5 was selected for the PPG trial for balanced Se-Sp. Fat-to-protein ratio cut-offs > 1.25, 1.35, 1.50, 1.60, and 1.70 resulted in Se-Sp of 100% to 49%, 96% to 59%, 75% to 78%, 33% to 90%, and 8% to 96%, respectively. The proportions of cows with FPR > 1.25, 1.35, 1.42, 1.50, 1.60, and 1.70 were 60%, 50%, 44%, 30%, 14%, and 6%, respectively. Incidences of clinical ketosis and milk yield were similar between cows that received 400 mL of PPG (n = 34) and control cows (n = 38). Prevalence of SCK at enrollment was 29.2%; therefore, FPR > 1.5 is not indicated for treatment. Lower cut-offs should be used for screening.

Bioenergy from stillage anaerobic digestion to enhance the energy balance ratio of ethanol production

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Searching for an invisibly decaying Higgs boson in e+e-, eγ, and γγ collisions

Higgs bosons can have a substantial invisible branching ratio in many extensions of the Standard Model, such as models where the Higgs bosons decay predominantly into light or massless weakly interacting Goldstone bosons. In this work, we examine the production mechanisms and backgrounds for invisibly decaying Higgs bosons at the Next Linear e+e- Collider operating in the modes e+e-, eγ, and γγ. We demonstrate that such machine is much more efficient to survey for invisibly decaying Higgs bosons than the Large Hadron Collider at CERN.

The mechanism of 234U 238U activity ratio enhancement in karstic limestone groundwater

Experimental etch/leach of Carboniferous Limestone gravels on a laboratory time-scale has demonstrated that 234U 238U activity ratios (AR's) greater than the radiochemical equilibrium value may be generated on short time-scales. The molar U/Ca and Mg/Ca ratios show that both U and Mg are leached preferentially relative to Ca whereas the molar U/Mg ratio is only slightly greater than that of the rock matrix. The generation of enhanced AR's is attributed to a two-stage process in which the limestone surface is dissolved by zero-order etch and silicate minerals so released are subjected to first-order chemical leach of U and Mg. The implications of these results for the production of enhanced AR's in Carboniferous Limestone groundwater are discussed. It is suggested that chemical leaching or exchange of U between groundwater and its particulate load or at the aquifer fluid-solid interface is an important mechanism controlling AR changes as groundwater migrates beyond a redox boundary. AR's for dissolved U in groundwater are more probably related to chemical equilibria than to groundwater age. © 1993.

Efeito túnel multidimensional em reações nucleares

Pós-graduação em Física - IFT

Strategic use of dietary electrolyte balance and ratio for broiler chickens

The literature reports dealing with the dietary electrolyte ratio (K+Cl)/ Na are rare, although the concept has been proposed by Mongin in 1981. Thus, its application appears to be limited as a nutritional strategy in feed formulation, which usually meets only the minimum nutritional recommendations in Na, K and Cl. The objective of this study was to evaluate the performance of broilers submitted to different dietary electrolyte balances (DEB) Na+K-Cl and dietary electrolyte ratio (DER) from 1 to 21 d of age. A total of 1575 male 1-d old broiler chicks were randomly assigned to 5 treatments with 9 replicates of 35 chicks each. The treatments consisted of diets with 5 relation of electrolytes, arising from combinations DEB/DER 150/3, 250/2, 250/3, 250/4 and 350/3, with use of NaCl, NaHCO3, KCl, K2SO4 and CaCl2. All diets were corn-soybean meal based and formulated to meet or exceed the NRC (1994) requirements. Chicks had ad libitum access to feed and water in floor pens with wood shavings as litter. Body weight, feed intake and feed conversion ratio were measured at 21 d of age. It was found that only the feed conversion was significantly affected (P = 0.0142) by the combinations of relation of electrolytes (DEB and DER). The supplementation levels in DEB and DER were made to fit the data into a surface analysis to allow increasing levels of DEB (150–350 mEq/kg) and narrow and broad ratio of DER (2–4). For the canonical analysis of response surface was obtained the stationary point for body weight (DEB = 255.77 mEq/kg, and DER = 2.73:1) the value was 942.02 g; for feed intake (DEB = 251.69 mEq / kg and DER = 3.51:1), the value was 1200.02 g; and for feed conversion (DEB = 254.62 mEq/kg and DER = 3.06:1) the value was 1.35. The results of this experiment indicated that the best performance was obtained with combinations of relation of electrolytes for DEB between 251 and 255 mEq/kg and DER between 2.73:1 and 3.5:1.

Influence of crown-to-implant ratio, retention system, restorative material, and occlusal loading on stress concentrations in single short implants

Purpose: The aim of this study was to assess the contributions of some prosthetic parameters such as crown-to-implant (C/I) ratio, retention system, restorative material, and occlusal loading on stress concentrations within a single posterior crown supported by a short implant. Materials and Methods: Computer-aided design software was used to create 32 finite element models of an atrophic posterior partially edentulous mandible with a single external-hexagon implant (5 mm wide × 7 mm long) in the first molar region. Finite element analysis software with a convergence analysis of 5% to mesh refinement was used to evaluate the effects of C/I ratio (1:1; 1.5:1; 2:1, or 2.5:1), prosthetic retention system (cemented or screwed), and restorative material (metal-ceramic or all ceramic). The crowns were loaded with simulated normal or traumatic occlusal forces. The maximum principal stress (σmax) for cortical and cancellous bone and von Mises stress (σvM) for the implant and abutment screw were computed and analyzed. The percent contribution of each variable to the stress concentration was calculated from the sum of squares analysis. Results: Traumatic occlusion and a high C/I ratio increased stress concentrations. The C/I ratio was responsible for 11.45% of the total stress in the cortical bone, whereas occlusal loading contributed 70.92% to the total stress in the implant. The retention system contributed 0.91% of the total stress in the cortical bone. The restorative material was responsible for only 0.09% of the total stress in the cancellous bone. Conclusion: Occlusal loading was the most important stress concentration factor in the finite element model of a single posterior crown supported by a short implant.

The chemical oxygen demand / total volatile acids ratio as an anaerobic treatability indicator for landfill leachates

In some operational circumstances a fast evaluation of landfill leachate anaerobic treatability is necessary, and neither Biochemical Methane Potential nor BOD/COD ratio are fast enough. Looking for a fast indicator, this work evaluated the anaerobic treatability of landfill leachate from São Carlos-SP (Brazil) in a pilot scale Anaerobic Sequence Batch Biofilm Reactor (AnSBBR). The experiment was conducted at ambient temperature in the landfill area. After the acclimation, at a second stage of operation, the AnSBBR presented efficiency above 70%, in terms of COD removal, utilizing landfill leachate without water dilution, with an inlet COD of about 11,000 mg.L-1, a TVA/COD ratio of approximately 0.6 and reaction time equal to 7 days. To evaluate the landfill leachate biodegradability variation over time, temporal profiles of concentration were performed in the AnSBBR. The landfill leachate anaerobic biodegradability was verified to have a direct and strong relationship to the TVA/COD ratio. For a TVA/CODTotal ratio lower than 0.20, the biodegradability was considered low, for ratios between 0.20 and 0.40 it was considered medium, and above 0.40 it was considered high.

Go/N ratio in tropical soils from Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Metalosupramoléculas discretas e Metal Organic Frameworks (MOFs) baseados em íons lantanídeos: design, síntese, caracterização e propriedades

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)