Management of vomplex systems: Modeling the biological pest control

The aim of this paper is to study the cropping system as complex one, applying methods from theory of dynamic systems and from the control theory to the mathematical modeling of the biological pest control. The complex system can be described by different mathematical models. Based on three models of the pest control, the various scenarios have been simulated in order to obtain the pest control strategy only through natural enemies' introduction. © 2008 World Scientific Publishing Company.

Panorama económico de América Latina, 1988 = Economic panorama of Latin America, 1988

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Phenotypic characterization of Candida spp. isolates from chronic periodontitis patients

Aim: Several typing methods for Candida spp. have been suggested in the literature in order to distinguish isolates for studies about the virulence or infection routes of these microorganisms and, in particular, for epidemiological purposes. The aim of this study was to establish a comparison between the phenotypic profile of oral Candida isolates from periodontitis patients and control individuals. Methods: The morphotyping and biotyping of 35 C. albicans isolates obtained from chronic periodontitis patients and 48 isolates from control individuals were performed. For morphotyping, the isolates were plated on malt extract agar and incubated for 10 days. Sixteen different morphotypes were observed for C. albicans, the most frequently observed being 0000 and 0001. Results: Biotype 0000 (complete absence of fringe) was most prevalent among the isolates obtained from periodontitis patients compared to those from control individuals, with statistical significance. Biotyping revealed 5 different biotypes with higher prevalence of the biotype 357 among the isolates from control and periodontitis groups. Conclusions: The results obtained by biotyping of the isolates did not permit to differentiate a characteristic model related to periodontal disease, whilst the morphotype 0000 was most frequently isolated from periodontitis patients.

La Coordinadora de Organizaciones Empresariales de Comercio Exterior: un caso de cooperación entre el sector público y el privado de México

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Aprovechamiento de las tierras tropicales en América Latina

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Spatial and temporal distribution of the shrimp nematopalaemon schmitti (Decapoda: Caridea: Palaemonidae) at a subtropical enclosed bay in South America

The spatio-temporal distribution of the soft bottom dwelling shrimp Nematopalaemon schmitti and the effect of environmental conditions (sediment characteristics, temperature, salinity and dissolved oxygen) on its abundance were studied at Ubatuba Bay, south-eastern coast of Brazil. Surveys were conducted monthly from September 1995 to August 1996. Each sampling set comprised eight different transects distributed within the bay. Comparisons of CPUE of shrimp among sampling stations demonstrated that the abundance of N. schmitti was the greatest during winter, when average water temperature within the bay was considerably lower than during the rest of the year. Most shrimps (more than 95%) were collected at a single transect located at the northernmost side of the bay, demonstrating the extremely patchy distribution of this species. A multiple regression analysis using data only from this northernmost transect indicated that temperature was the most relevant factor affecting the abundance of N. schmitti during the year. Copyright © 2009 Marine Biological Association of the United Kingdom.

El papel de la legislación y la regulación en las políticas de uso eficiente de la energía en la Unión Europea y sus Estados Miembros

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Nuevas experiencias de concertación público-privada: las corporaciones para el desarrollo local: estudio de casos en las comunas de Santiago y Huechuraba, Area Metropolitana de Santiago de Chile

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Structural refinement and photoluminescence properties of cube-like (Ca 1-xCu x)TiO 3 crystals synthesized by the microwave-hydrothermal method

In this work, (Ca 1-xCu x)TiO 3 crystals with (x = 0, 0.01 and 0.02), labeled as CTO, CCTO1 and CCTO2, were synthesized by the microwave-hydrothermal method at 140°C for 32 min. XRD patterns (Fig. 1), Rietveld refinement and FT-Raman spectroscopy indicated that these crystals present orthorhombic structure Pbnm. Micro-Raman and XANES spectra suggested that the substitution of Ca by Cu in A-site promoted a displacement of the [TiO6]-[TiO6] clusters adjacent from its symmetric center, which leads distortions on the [CaO 12] clusters neighboring and consequently cause the strains into the CaTiO3 lattice. FE-SEM images showed that these crystals have an irregular shape as cube like probably indicating an Ostwald-ripening and self-assemble as dominant mechanisms to crystals growth. The powders presented an intense PL blue-emission.

Nitrogen excretion during embryonic development of the green iguana, Iguana iguana (Reptilia; Squamata)

Development within the cleidoic egg of birds and reptiles presents the embryo with the problem of accumulation of wastes from nitrogen metabolism. Ammonia derived from protein catabolism is converted into the less toxic product urea or relatively insoluble uric acid. The pattern of nitrogen excretion of the green iguana, Iguana iguana, was determined during embryonic development using samples from allantoic fluid and from the whole homogenized egg, and in hatchlings and adults using samples of blood plasma. Urea was the major excretory product over the course of embryonic development. It was found in higher concentrations in the allantoic sac, suggesting that there is a mechanism present on the allantoic membrane enabling the concentration of urea. The newly hatched iguana still produced urea while adults produced uric acid. The time course of this shift in the type of nitrogen waste was not determined but the change is likely to be related to the water relations associated with the terrestrial habit of the adult. The green iguana produces parchment-shelled eggs that double in mass during incubation due to water absorption; the eggs also accumulate 0.02. mM of urea, representing 82% of the total measured nitrogenous residues that accumulate inside the allantois. The increase in egg mass and urea concentration became significant after 55. days of incubation then were unchanged until hatching. © 2012 Elsevier Inc.

Broadband NIR emission in novel sol-gel Er3+-doped SiO 2-Nb2O5 glass ceramic planar waveguides for photonic applications

This paper reports on the sol-gel preparation and structural and optical characterization of new Er3+-doped SiO2-Nb 2O5 nanocomposite planar waveguides. Erbium-doped (100-x)SiO2-xNb2O5 waveguides were deposited on silica-on-silicon substrates and Si(1 0 0) by the dip-coating technique. The waveguides exhibited uniform refractive index distribution across the thickness, efficient light injection at 1538 nm, and low losses at 632 and 1538 nm. The band-gap values lied between 4.12 eV and 3.55 eV for W1-W5, respectively, showing an excellent transparency in the visible and near infrared region for the waveguides. Fourier Transform Infrared (FTIR) Spectroscopy analysis evidenced SiO2-Nb2O5 nanocomposite formation with controlled phase separation in the films. The HRTEM and XRD analyses revealed Nb2O5 orthorhombic T-phase nanocrystals dispersed in a silica-based host. Photoluminescence (PL) analysis showed a broad band emission at 1531 nm, assigned to the 4I13/2 → 4I15/2 transition of the Er3+ ions present in the nanocomposite, with a full-width at half medium of 48-68 nm, depending on the niobium content and annealing. Hence, these waveguides are excellent candidates for application in integrated optics, especially in EDWA and WDM devices. © 2012 Elsevier B.V. All rights reserved.

Guided implant surgery: What is the influence of this new technique on bone cell viability?

Purpose: To evaluate the effect of implant osteotomy on immediate bone cell viability, comparing guided surgery for implant placement with the classic drilling procedure. Materials and Methods: For this study, 20 rabbits were used. The animals were divided into a guided surgery group (GG) and a control group (CG) and were then divided into 4 subgroups - subgroups 1, 2, 3, and 4 - corresponding to drills used 10, 20, 30, and 40 times, respectively. All animals received 5 osteotomies in each tibia, by use of the classic drilling procedure in one tibia and guided surgery in the other tibia. The osteotomized areas were removed and processed immunohistochemically for detection of osteocalcin, receptor activator of nuclear factor κB ligand (RANKL), osteoprotegerin (OPG), and caspase 3. Results: Immunohistochemical analysis showed that osteocalcin expression was initially higher in the CG and remained constant after drill reutilization. Although the expressions of RANKL and OPG were not statistically different for the GG and CG, the RANKL/OPG ratio tended to be higher for the GG. Moreover, caspase 3 expression was elevated in the GG, proportionally to the number of osteotomies, indicating an increase in the apoptosis index in the GG. Conclusions: The classic drilling procedure is more favorable to cell viability than guided surgery.© 2013 American Association of Oral and Maxillofacial Surgeons.

Life, the universe, and everything: An education outreach proposal to build a traveling astrobiology exhibit

Astrobiology is a transdisciplinary field with extraordinary potential for the scientific community. As such, it is important to educate the community at large about the growing importance of this field to increase awareness and scientific content learning and expose potential future scientists. To this end, we propose the creation of a traveling museum exhibit that focuses exclusively on astrobiology and utilizes modern museum exhibit technology and design. This exhibit (the Astrobiology Road Show), organized and evaluated by an international group of astrobiology students and postdocs, is planned to tour throughout the Americas. Copyright © 2013, Mary Ann Liebert, Inc. 2013.

From cytoplasm to environment: The inorganic ingredients for the origin of life

Early in its history, Earth's surface developed from an uninhabitable magma ocean to a place where life could emerge. The first organisms, lacking ion transporters, fixed the composition of their cradle environment in their intracellular fluid. Later, though life adapted and spread, it preserved some qualities of its initial environment within. Modern prokaryotes could thus provide insights into the conditions of early Earth and the requirements for the emergence of life. In this work, we constrain Earth's life-forming environment through detailed analysis of prokaryotic intracellular fluid. Rigorous assessment of the constraints placed on the early Earth environment by intracellular liquid will provide insight into the conditions of abiogenesis, with implications not only for our understanding of early Earth but also the formation of life elsewhere in the Universe. Copyright © 2013, Mary Ann Liebert, Inc. 2013.

Role of brain nitric oxide in the cardiovascular control of bullfrogs

The goal of the present study was to determine if nitric oxide (NO) acting on the brain of bullfrog (Lithobates catesbeianus) is involved in arterial pressure and heart rate (HR) control by influencing sympathetic activity. We investigated the effect of intracerebroventricular injections of l-NMMA (a nonselective NO synthase inhibitor) on mean arterial blood pressure (MAP), HR and cutaneous vascular conductance (CVC) of pelvic skin after intravenous injection of α or β adrenergic blockers, prazosin or sotalol, respectively. Arterial pressure was directly measured by a telemetry sensor inserted in the aortic arch of animals. l-NMMA increased MAP, but did not change HR. This hypertensive response was inhibited by the pre-treatment with prazosin, but accentuated by sotalol. The effect of l-NMMA on MAP was also inhibited by i.v. injections of the ganglionic blocker, hexamethonium. Thus, NO acting on the brain of bullfrog seems to present a hypotensive effect influencing the sympathetic activity dependent on α and β adrenergic receptors in the periphery. © 2013 Elsevier Inc.