Performance of Balanced Two-Stage Empirical Predictors of Realized Cluster Latent Values from Finite Populations: A Simulation Study

Predictors of random effects are usually based on the popular mixed effects (ME) model developed under the assumption that the sample is obtained from a conceptual infinite population; such predictors are employed even when the actual population is finite. Two alternatives that incorporate the finite nature of the population are obtained from the superpopulation model proposed by Scott and Smith (1969. Estimation in multi-stage surveys. J. Amer. Statist. Assoc. 64, 830-840) or from the finite population mixed model recently proposed by Stanek and Singer (2004. Predicting random effects from finite population clustered samples with response error. J. Amer. Statist. Assoc. 99, 1119-1130). Predictors derived under the latter model with the additional assumptions that all variance components are known and that within-cluster variances are equal have smaller mean squared error (MSE) than the competitors based on either the ME or Scott and Smith's models. As population variances are rarely known, we propose method of moment estimators to obtain empirical predictors and conduct a simulation study to evaluate their performance. The results suggest that the finite population mixed model empirical predictor is more stable than its competitors since, in terms of MSE, it is either the best or the second best and when second best, its performance lies within acceptable limits. When both cluster and unit intra-class correlation coefficients are very high (e.g., 0.95 or more), the performance of the empirical predictors derived under the three models is similar.     

Use of the transtheoretical model for behavioral change in women's health

Application of stage-based counseling approaches using the transtheoretical model can help providers of primary care to women take full advantage of windows of opportunity for promoting women's health. The transtheoretical model enables the counselor or clinician to individualize the message provided to patients based on their stage. This matching of stage of change with the appropriate principles and processes of change will enable primary care providers to more effectively bring about behavioral change and improve the health status of our patients.     

Corrosion of metals and alloys in molten glasses. Part 2: nickel and cobalt high chromium superalloys behaviour and protection

Electrochemical methods have been used for the characterisation of high chromium alloys corrosion in molten glasses (cobalt and nickel base alloys in a borosilicate glass at 1050 °C, with rotating working electrodes). All the tested alloys are active but passivable materials. The active state is characterised by a rapid dissolution of the constitutive elements of the alloy in the glass melt. The passive state can be obtained by an air oxidation of the alloys (called preoxidation) or with a temporary anodic polarisation of the alloy. The obtained passive state is due to the presence of a thin protective chromia scale.     

Solar photo-Fenton treatment of chip board production waste water

In a joint project the Universidade Federal de Uberlândia and the German Aerospace Center are developing solar water treatment technologies for industrial applications. Wastewater from chip-board production is difficult to detoxify by standard processes. Different advanced oxidation processes using solar light were tested on this effluent. In opposition to TiO₂ treatment, the application of the photo-Fenton process using a compound parabolic collector (CPC) type solar reactor shows excellent results, with a reduction in the COD higher than 70% with the application of about 800 kJ m⁻² of UVA radiation. HPLC analysis shows an efficient degradation of the organic matter present in the effluent (formaldehyde, melamine, urea, wood extractives, lignin and urea/formaldehyde and melamine/formaldehyde resins fragments) prior to their complete disappearance.     

Variable-Concentration and Boundary Effects on Debris Flow Discharge Predictions

The uniform flow of natural debris mixture is generally modeled assuming a uniform solid concentration and the absence of lateral walls. The resulting flow discharges are, however, higher than those observed and, in the case of erodible boundaries, the equilibrium between the moving and nonmoving mixtures cannot be simulated. Such a model also cannot simulate the effect of lateral rigid boundaries that generate lateral velocity and concentration gradients. This paper describes a numerical model to determine the concentration and velocity distribution in the two directions transverse to the flow. The model is applied to a uniform laminar flow of a mixture with a shear-thickening Herschel–Bulkley constitutive behavior, with rheological parameters expressed in terms of the local solid concentration, and allows the simulation of different conditions in the presence of both erodible and rigid boundaries.     

Visceral afferent pathways to the thalamus and olfactory tubercle: behavioral implications

The goal of this study was to support the hypothesis that visceral signals may integrate and influence behavior by way of direct pathways from the nucleus tractus solitarii (NTS) to the olfactory tubercle and the midline/intralaminar thalamus. An anterograde tracer, biotinylated dextran amine (BDA) was iontophoresed bilaterally into the caudal NTS to optimize terminal labeling. NTS-cortical projections traversed both limbs of the diagonal bands providing heavy innervation, and terminated lightly within layer 3 of the olfactory tubercle. NTS-thalamic projections terminated within anterior and, as previously shown, posterior divisions of nucleus paraventricularis thalami and avoided the adjoining mediodorsal thalamic nucleus. Heretofore unrecognized projections were traced to the parafascicular and reuniens thalamic nuclei, and the peripeduncular nucleus. Control experiments identified the nucleus gracilis as the principal source of ascending projections to ventroposterior lateral, posterior and intralaminar thalamic nuclei. Our data corroborate the supposition that olfactory signals may integrate with visceral stimuli in the striatal compartment of olfactory tubercle. NTS projections encompass thalamic nuclei that project topographically to the prefrontal cortex, hippocampus and ventral (limbic) striatum, regions activated by visceral stimulation. Structural data support the idea that compartments of the non-discriminative thalamus may contribute to perception and behavioral responses to visceral stimulation.     

From Natural Forms to Models

The course presented at the Istituto Statale d’Arte (ISA), a high school for visual and design arts, is a guided tour of the world of forms of seashells. The main goal of this course is to present to the student prevalently scientific methods of interpretation of forms.     

Diagnostic imaging of Tietze's syndrome. Comparison of computerized tomography and ultrasonography

Tietze's syndrome is an uncommon disease characterized by the absence of any systemic symptom; imaging techniques play a major role in the diagnosis of this condition. A control group including 10 normal subjects and 4 patients with clinical evidence of Tietze's syndrome were submitted to US; 3/4 patients underwent CT too. In the lesion site, US demonstrated thickened cartilage and inhomogeneously increased echogenicity in 4 patients, blurred outline in 3 patients and a hypoechoic halo in 1 patient. CT showed thickened cartilage and blurred outline in 3 patients and hypodense cartilage in 1 patient. Both methods were very useful to diagnose the disease in all cases. The authors conclude that US plays a major role in the diagnosis of Tietze's syndrome thanks to its harmlessness, repeatability and cost-effectiveness.     

Protective Effect of Tyrosol and S-Adenosylmethionine against Ethanol-Induced Oxidative Stress of Hepg2 Cells Involves Sirtuin 1, P53 and Erk1/2 Signaling

Oxidative stress plays a major role in ethanol-induced liver damage, and agents with antioxidant properties are promising as therapeutic opportunities in alcoholic liver disease. In the present work, we investigated the effect of S-adenosylmethionine (AdoMet), Tyrosol (Tyr), and their combination on HepG2 cells exposed to ethanol exploring the potential molecular mechanisms. We exposed HepG2 cells to 1 M ethanol for 4 and 48 h; thereafter, we recorded a decreased cell viability, increase of intracellular reactive oxygen species (ROS) and lipid accumulation, and the release into culture medium of markers of liver disease such as triacylglycerol, cholesterol, transaminases, albumin, ferritin, and homocysteine. On the other hand, AdoMet and Tyrosol were able to attenuate or antagonize these adverse changes induced by acute exposure to ethanol. The protective effects were paralleled by increased Sirtuin 1 protein expression and nuclear translocation and increased ERK1/2 phosphorylation that were both responsible for the protection of cells from apoptosis. Moreover, AdoMet increased p53 and p21 expression, while Tyrosol reduced p21 expression and enhanced the expression of uncleaved caspase 3 and 9, suggesting that its protective effect may be related to the inhibition of the apoptotic machinery. Altogether, our data show that AdoMet and Tyrosol exert beneficial effects in ethanol-induced oxidative stress in HepG2 cells and provide a rationale for their potential use in combination in the prevention of ethanol-induced liver damage.     

Analytical metrological characterization of the three-parameter sine fit algorithm

The three-parameter sine fit is a well known algorithm used in IEEE standard 1241-2000 for ADC characterization to estimate sine wave parameters from recorded data. An analytical metrological characterization of that algorithm is carried out in terms of its design parameters, namely the sampling rate and the number of samples. Optimal and sub-optimal parameters' sets are found. Focusing on the amplitude estimation, an approximated statistical characterization of the second order is given in the most general case of zero mean additive noise, whereas the exact probability density function is found for the optimal set of algorithm parameters in the case of additive white Gaussian noise. In this particular case, the frequency behavior of the algorithm is fully analyzed and the exact frequency response of the amplitude is also found. An approximated expression that is easier to use is then presented and discussed. Simulation results for a single set of parameters are presented in order to graphically illustrate the analytical results.