Search

In this research, the influence of the stiffness irregularity and the p-delta effect on the structural behavior of a reinforced concrete building is analyzed. The main objective is to determine the impact of the stiffness irregularity and the p-delta effect on the structural behavior in regular and irregular buildings. First, the linear dynamic analysis procedure is performed in order to determine the structural response in terms of drifts, shear force and moments per floor. Subsequently, we proceed with the nonlinear static analysis procedure to obtain the capacity curve of the structure. The post elastic stiffness and the overall ductility of the structure are determined from the capacity curve. Finally, a comparative analysis of the responses from the linear and nonlinear analysis is carried out to determine the percentage variation of the results. When analyzing the structures that consider the stiffness irregularity and the p-delta effect, variations of up to 16.50%, 11.00% and 14.00% have been obtained in drifts, shear force and moments per floor respectively, which are considerable values. When the p-delta effect is considered in structures with the presence of stiffness irregularity, there is a variation in stiffness of up to 59.85%. With this result it is explained that the p-delta effect produces a greater degradation of the overall stiffness of the structure.

11 pages, 4 figures, 4 tables.-- PMID: 12809298 [PubMed]., Surface soil samples from various altitudes on Tenerife Island, ranging from sea level up to 3400 m above mean sea level, were analyzed to study the distribution of 26 polycyclic aromatic hydrocarbons (PAHs) in a remote subtropical area. The stable atmospheric conditions in this island define three vertically stratified layers: marine boundary, trade-wind inversion, and free troposphere. Total PAH concentrations, 1.9 to 6000 µg/kg dry wt., were high when compared with those in tropical areas and in a similar range to those in temperate areas. In the marine boundary layer, fluoranthene (Fla), pyrene (Pyr), benz[a]anthracene (BaA), and chrysene (C + T) were largely dominant. The predominance of Fla over Pyr may reflect photo-oxidative processes during atmospheric transport, although coal combustion inputs cannot be excluded. The PAHs found in higher concentration in the soils from the inversion layer were benzo[b + j]fluoranthene (BbjF) + benzo[k]fluoranthene (BkF) > benzo[e]pyrene (BeP) {approx} indeno[1,2,3-cd]pyrene (Ind) > benzo[a]pyrene (BaP) {cong} benzo[ghi]perylene (Bghi) > coronene (Cor) {cong} dibenz[a,h]anthracene (Dib), reflecting that high temperatures and insolation prevent the accumulation of PAHs more volatile than BbjF in significant amounts. These climatic conditions involve a process of standardization that prevents the identification of specific PAH sources such as traffic, forest fires, or industrial inputs. Only soils with high total organic carbon (TOC) (e.g., 10–30%) preserve the more volatile compounds such as phenanthrene (Phe), methylphenanthrenes (MPhe), dimethylphenanthrenes (DMPhe), and retene (Ret). However, no relation between PAHs and soil TOC and black carbon (BC) was found. The specific PAH distributions of the free tropospheric region suggest a direct input from pyrolytic processes related to the volcanic emission of gases in Teide., Financial support from GLOBAL-SOC (EC Project ENV4-CT97-0638) is acknowledged.

50 children under the age of 15 years were studied who had been hospitalized in two hospitals in the Dominican Republic with HIV diagnosed by the presence of biphasic hyperbilirubinemia and elevation of glutamic-pyruvic and glutamic-oxalacetic transaminases. The sera of the patients were examined for the presence of leptospirotic immunoglobulin M (IgM) antibodies by means of the enzymatic immunoassay method (UREASA-ELISA). The Leptospira-positive sera were also investigated for the presence of hepatitis B surface antigen (HBsAg) and for the IgM antibody (ab) of the hepatitis A virus (ab-HAV) by ELISA. 5 cases were positive for IgM Leptospira antibodies (10%), not finding in this percentage the presence of HBsAg; 3 of the 5 Leptospira-positive samples demonstrated the presence of ab-HVA-IgM. Only 2 cases (4%) presented IgM Leptospira antibodies. Out of the 5 cases with IgM antibodies, males predominated (3/5). When compared to negative cases, however, there were more rural elements among them than in negative cases: regarding origins (10% vs. 16%), agricultural workers (40% vs. 20%), contact with cattle and fresh water (80% vs. 40%), and daily contact with humid soil in living quarters (60% vs. 48%). The clinical picture of the 5 positive cases featured myalgia (p = 0.05) and abdominal pain (p = 0.05). The stiffness of neck was relatively more frequent in positive cases (20%) than in negative cases (7%); also, fever (100% vs. 80%), vomiting (60% vs. 22%), headache (80% vs. 56%), constipation (20% vs. 9%), and hepatomegaly (100% vs. 71%). There was clear evidence that leptospirotic infection must be watched and also its association with acute infectious hepatitis.

Diez clones de chironja se evaluaron por 6 años en las Subestaciones Experimentales Agrícolas de Isabela, Corozal y Adjuntas. El análisis estadístico de los datos proveyó estimados sobre la naturaleza y magnitud de los componentes de varianza de las 15 características que se presentan en el cuadro 2 . Los componentes de variación para las características de los clones fueron mayores que en las interacciones de primero y segundo orden. En la interacción variedad x localidad, la única característica que tuvo componente de variación significativo (al 1 %) fue el diámetro del injerto, la cual indica la necesidad de sembrar en varias localidades cuando se llevan a cabo experimentos similares a los que se informan. En la interacción variedad X localidad X año, las únicas características con sus componentes de variación significativos fueron el peso de las frutas por árbol, el Brix y el contenido de ácido cítrico, mientras que en ninguna de las características de la interacción de clones x años hubo componentes de variación significativos. La explicación sobre la interacción de genotipo x ambiente se presenta en el texto. La varianza para error entre parcelas (oe 2) fue bien grande relativamente, la cual sugiere que en un experimento de esta índole debe aumentarse el número de repeticiones.

The behavior of 10 chironja clones, studied at the Isabela, Corozal and Adjuntas Substations, demonstrated that graftage of chironja on sour orange rootstock is incompatible as determined by the scion to rootstock ratio. This incompatibility increased with tree age and was greatest in Adjuntas, intermediate in Corozal, and least in lsabela. The Adjuntas trees had significantly thinner trunk (either rootstock or scion) diameter, and smaller canopy volume than those of Isabela and Corozal. This probably accounted for the smaller size of fruits and the lower fruit production in Adjuntas as compared to those of Isabela and Corozal. The Isabela trees had significantly greater trunk (rootstock and scion) diameter and smaller scion/rootstock ratio and canopy volume than those of Corozal. The weight and number of fruits per tree increased with age from 1970-1972, while the weight per fruit was reduced at the same time. The chironja clone 2-4 produced significantly the highest crop and the heaviest fruits; therefore, its multiplication should be encouraged.