National accounts of Caribbean countries: methodologies, sources and quality, and a comparative Caribbean study

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Sistemas de protección social en América Latina y el Caribe: Ecuador

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Ventricular systolic reserve in asymptomatic children previously treated with low doses of anthracyclines: A longitudinal, prospective exercise echocardiography study

Background: The time course of mild cardiotoxicity induced by anthracycline remains unknown. The aim of this study was to evaluate the long-term evolution of decreased myocardial reserve in children previously treated with a cumulative dose of anthracycline up to 100mg/m 2. Patients and Methods: Twenty-seven asymptomatic cancer survival patients (25 with lymphoblastic leukemia), in continuous remission and off treatment for >12 months with no alterations in conventional echocardiograms were evaluated by exercise echocardiography at 37±15.4 months (T1) and 101±24 months (T2) after finishing treatment (ADRIA group). This group was compared with 25 healthy individuals (control group) similar to the ADRIA group with respect to age and body surface area (BSA). All individuals underwent treadmill exercise testing according to Bruce protocol. Echocardiograms were performed before and immediately after exercise. Results: The groups were similar regarding cardiac structure and left ventricular (LV) systolic function at rest at T1 and T2. The growth of LV posterior wall thickness related to BSA was lower in the ADRIA group at T2. Post exercise, smaller LV ejection indexes and attenuated changes in the afterload in ADRIA group were observed at T1 and T2. Conclusion: The decreased systolic reserve induced by a low dose of anthracycline in asymptomatic children and adolescents remains unaffected over a 5-year period, suggesting that positive outcomes in chronic cardiotoxicity would be expected in patients with mild impairment after anthracycline treatment. © 2011 Wiley Periodicals, Inc.

The thermal, rheological and structural properties of cassava starch granules modified with hydrochloric acid at different temperatures

Starch is arguably one of the most actively investigated biopolymer in the world. In this study, the native (untreated) cassava starch granules (Manihot esculenta, Crantz) were hydrolyzed by standard hydrochloric acid solution at different temperatures (30 °C and 50 °C) and the hydrolytic transformations were investigated by the following techniques: simultaneous thermogravimetry-differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), as well as non-contact atomic force microscopy (NC-AFM), X-ray diffraction (XRD) powder patterns, and rapid viscoamylographic analysis (RVA). After the treatment with hydrochloric acid at different temperatures, the thermal stability, a gradual loss of pasting properties (viscosity), alterations in the gelatinization enthalpy (ΔHgel), were observed. The use of NC-AFM and XRD allowed the observation of the surface morphology and topography of the starch granules and changes in crystallinity of the granules, respectively. © 2012 Elsevier B.V. All rights reserved.

Mechanochemical synthesis of yttrium manganite

Yttrium manganite (YMnO3) is a multiferroic material, which means that it exhibits both ferromagnetic and ferroelectric properties, so making it interesting for a variety of technological applications. In this work, single-phase YMnO3 was prepared for the first time by mechanochemical synthesis in a planetary ball mill. The YMnO3 was formed directly from the highly activated constituent oxides, Y 2O3 and Mn2O3, after 60 min of milling time. During prolonged milling, the growth of the particles occurred. The cumulative energy introduced into the system during milling for 60 min was 86 kJ/g. The X-ray powder-diffraction analysis indicates that the as-prepared samples crystallize with an orthorhombic (Pnma) YMnO3 structure. The morphology and chemical composition of the powder were investigated by SEM and FESEM. The magnetic properties of the obtained YMnO3 powders were found to change as a function of the milling time in a manner consistent with the variation in the nanocomposite microstructure. © 2012 Elsevier B.V. All rights reserved.

Nebular gas drag and planetary accretion with eccentric high-mass planets

Aims.We investigate the dynamics of pebbles immersed in a gas disk interacting with a planet on an eccentric orbit. The model has a prescribed gap in the disk around the location of the planetary orbit, as is expected for a giant planet with a mass in the range of 0.1-1 Jupiter masses. The pebbles with sizes in the range of 1 cm to 3 m are placed in a ring outside of the giant planet orbit at distances between 10 and 30 planetary Hill radii. The process of the accumulation of pebbles closer to the gap edge, its possible implication for the planetary accretion, and the importance of the mass and the eccentricity of the planet in this process are the motivations behind the present contribution. Methods. We used the Bulirsch-Stoer numerical algorithm, which is computationally consistent for close approaches, to integrate the Newtonian equations of the planar (2D), elliptical restricted three-body problem. The angular velocity of the gas disk was determined by the appropriate balance between the gravity, centrifugal, and pressure forces, such that it is sub-Keplerian in regions with a negative radial pressure gradient and super-Keplerian where the radial pressure gradient is positive. Results. The results show that there are no trappings in the 1:1 resonance around the L 4 and L5 Lagrangian points for very low planetary eccentricities (e2 < 0.07). The trappings in exterior resonances, in the majority of cases, are because the angular velocity of the disk is super-Keplerian in the gap disk outside of the planetary orbit and because the inward drift is stopped. Furthermore, the semi-major axis location of such trappings depends on the gas pressure profile of the gap (depth) and is a = 1.2 for a planet of 1 MJ. A planet on an eccentric orbit interacts with the pebble layer formed by these resonances. Collisions occur and become important for planetary eccentricity near the present value of Jupiter (e 2 = 0.05). The maximum rate of the collisions onto a planet of 0.1 MJ occurs when the pebble size is 37.5 cm ≤ s < 75 cm; for a planet with the mass of Jupiter, it is15 cm ≤ s < 30 cm. The accretion stops when the pebble size is less than 2 cm and the gas drag dominates the motion. © 2013 ESO.

Effects of sublethal doses of imidacloprid in malpighian tubules of africanized Apis mellifera (Hymenoptera, Apidae)

In Brazil, imidacloprid is a widely used insecticide on agriculture and can harm bees, which are important pollinators. The active ingredient imidacloprid has action on the nervous system of the insects. However, little has been studied about the actions of the insecticide on nontarget organs of insects, such as the Malpighian tubules that make up the excretory and osmoregulatory system. Hence, in this study, we evaluated the effects of chronic exposure to sublethal doses of imidacloprid in Malpighian tubules of Africanized Apis mellifera. In the tubules of treated bees, we found an increase in the number of cells with picnotic nuclei, the lost of part of the cell into the lumen, and a homogenization of coloring cytoplasm. Furthermore, we observed the presence of cytoplasmic vacuolization. We confirmed the increased occurrence of picnotic nuclei by using the Feulgan reaction, which showed the chromatin compaction was more intense in the tubules of bees exposed to the insecticide. We observed an intensification of the staining of the nucleus with Xylidine Ponceau, further verifying the cytoplasmic negative regions that may indicate autophagic activity. Additionally, immunocytochemistry experiments showed TUNEL positive nuclei in exposed bees, implicating increased cell apoptosis after chronic imidacloprid exposure. In conclusion, our results indicate that very low concentrations of imidacloprid lead to cytotoxic activity in the Malpighian tubules of exposed bees at all tested times for exposure and imply that this insecticide can alter honey bee physiology. © 2013 Wiley Periodicals, Inc.

Aspectos fisiológicos e bioquímicos de cultivares de soja submetidos a déficit hídrico induzido por peg 6000

In soybean culture water deficit is one of the most limiting factors to the maximum yield obtained. Genotypes identification with drought tolerance capacity is fundamental to solve this problem. The objective in this paper was analyze the physiological quality and physiological and biochemical responses of soybeans cultivars (MG/BR 46 Conquista, UFUS Carajás, UFUS Impacta, UFUS Riqueza and UFUS Xavante) submitted to water stress with PEG 6000 solutions in different levels of osmotic potentials (0; -0,1; -0,2; -0,3 and -0,4 MPa). Physiological quality of cultivars were evaluated by seedling length test and fresh and dry biomass. The biochemical responses were evaluated by detection of indol-acetic acid (IAA), by saccharose content and seedling water transportation. UFUS Riqueza presented the best performance in physiological quality tests, saccharose content, absorption and water absorption velocity in seedling. UFUS Xavante showed the highest IAA's concentration and the greater weight of seedling in water transportation test.

Effect of ionic strength solution on the stability of chitosan-DNA nanoparticles

Chitosan-DNA nanoparticles employed in gene therapy protocols consist of a neutralised, stoichiometric core and a shell of the excess of chitosan which stabilises the particles against further coagulation. At low ionic strength, these nanoparticles possess a high stability; however, as the ionic strength increases, it weakens the electrostatic repulsion which can play a decisive part in the formation of highly aggregated particles. In this study, new results about the effect of ionic strength on the colloidal stability of chitosan-DNA nanoparticles were obtained by studying the interaction between chitosans of increasing molecular weights (5, 10, 16, 29, 57 and 150 kDa) and calf thymus DNA. The physicochemical properties of polyplexes were investigated by means of dynamic light scattering, static fluorescence spectroscopy, optic microscopy, transmission electronic microscopy and gel electrophoresis. After subsequent addition of salt to the nanoparticles solution, secondary aggregation increased the size of the polyplexes. The nanoparticles stability decreased drastically at the ionic strengths 150 and 500 mM, which caused the corresponding decrease in the thickness of the stabilising shell. The morphologies of chitosan/DNA nanoparticles at those ionic strengths were a mixture of large spherical aggregates, toroids and rods. The results indicated that to obtain stable chitosan-DNA nanoparticles, besides molecular weight and N/P ratio, it is quite important to control the ionic strength of the solution. © 2013 Copyright Taylor and Francis Group, LLC.

Influência da aptidão aeróbia no running anaerobic sprint test (RAST)

The aim of this study was to investigate the possible influence of different levels of aerobic fitness (VO2MAX) on the parameters of the running anaerobic sprint test (RAST). Thirty-eight subjects (Age = 18.1 ± 2.5 years, Height = 173 ± 1 cm and Body mass = 65.1 ± 6.5 kg) were classified into two groups, low and high aerobic fitness (LAF: n = 22 and HAF: n = 16). The VO2MAX was determined by an incremental exercise performed until exhaustion. The RAST was composed of six maximal efforts of 35m separated by 10s passive recovery. The VO2MAX was significantly different between groups (LAF = 51.7 ± 1.9 mL.kg -1.min-1; HAF = 58.6 ± 3.1 mL.kg -1.min-1). The mean power (MP) was significantly higher in the LAF (552.7 ± 132.1 W) in relation to the HAF group (463.6 ± 132.8 W). The impulse (ImP) was significantly correlated with the VO 2MAX in HAF. It can be concluded that there is an indication that the aerobic metabolism exerts an influence on the completion of RAST.

Modelos de socialización en América Latina y el Caribe: investigación documental

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Marcha de absorção de macronutrientes e de micronutrientes em mudas de goiabeira Paluma e Século XXI

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Alterações no número de cópias genômicas em mastocitomas cutâneos caninos

Pós-graduação em Medicina Veterinária - FCAV

Centroamérica: evolución de la integración económica durante 1995

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