929 resultados para fragmentation and integration
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Includes bibliography
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Includes bibliography
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Includes bibliography
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Studies of sub-lethal effects of pesticide residues on stingless bees are scarce and morphological analysis of organs would add information to toxicological analysis in order to clarify the continuous exposure of Scaptotrigona postica to insecticides. The aim of this study was to evaluate the morphology and histochemistry of the Malpighian tubules (excretory organ) of S. postica exposed to fipronil or boric acid to detect cellular responses that indicate toxicity or adaptative mechanisms to stress induced by exposure of worker bees to low doses of these chemical compounds. Newly emerged bees were submitted to toxicological bioassays and morphological analyses by optical microscopy and Transmission Electron Microscopy, as well as histochemical methods, were performed to detect proteins and glycoconjugates. Additionally, immunohistochemical detection of DNA fragmentation and HSP70 (70-kDa Heat shock protein) were performed to detect cell death and stress response, respectively. Statistical analysis, for the bioassays conducted with ingestion of contaminated diet with boric acid at 0.75% (w/w) or with fipronil at 0.1μg/kg of food, showed that the survival of bees that ingested the contaminated diets were significantly different to the survival rate presented by the control group (P<0.0001). Although some characteristics indicative of initiation of cell death were observed, the cells remained metabolically active in the processes of excretion and inactivation of chemical compounds. The data from this study reinforce the importance of research on sublethal effects of low doses of pesticides on bees in an attempt to assess a possible realistic dose and evaluate the risk assessment of stingless bee S. postica foraging in the vicinity of cultivated fields and/or in green urban areas. © 2013 Elsevier Ltd.
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Includes bibliography
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Distemper leukoencephalitis is a disease caused by the canine distemper virus (CDV) infection. It is a demyelinating disease affecting mainly the white matter of the cerebellum and areas adjacent to the fourth ventricle; the enzymes of the matrix metalloproteinases (MMPs) group, especially MMP-2 and MMP-9 have a key role in the myelin basic protein fragmentation and in demyelination, as well as in leukocyte traffic into the nervous milieu. To evaluate the involvement of MMPs during subacute distemper leukoencephalitis, we measured the levels of MMP-2 and MMP-9 by zymography in the cerebrospinal fluid (CSF) and in the cerebellum of 14 dogs naturally infected with CDV and 10 uninfected dogs. The infected dogs presented high levels of pro-MMP-2 in the CSF and elevated levels of pro-MMP-2 and pro-MMP-9 in the cerebellar tissue. Active MMP-2 was detected in the CSF of some infected dogs. As active MMP-2 and MMP-9 are required for cellular migration across the blood-brain barrier and any interference between MMPs and their inhibitors may result in an amplification of demyelination, this study gives additional support to the involvement of MMPs during subacute distemper leukoencephalitis and suggests that MMP-2 and MMP-9 may take part in the brain inflammatory changes of this disease. © 2013 Elsevier B.V.
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This issue of the FAL Bulletin provides information on trends in current maritime transport and their implications for Latin America and the Caribbean, as well as some consequences for the ports in the region. This article updates some of the information contained in Recursos naturales e infraestructura series, No. 82 (ECLAC). This issue is based on a paper prepared by Ricardo J. Sánchez, Division of Natural Resources and Infrastructure, with the collaboration of Myriam Echeverría, Division of International Trade and Integration.
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This article refers to rules of origin included in the main Economic Integration Agreements signed by members of the Latin American Integration Association (LAIA). Issues relating to trade facilitation and reduction of transaction costs of international trade in goods are also discussed.The author is on the staff of the International Trade and Integration Division of ECLAC.
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The study recently published by the Division of International Trade and Integration of ECLAC considers that 2005 will be a good year for trade in the countries of the region. Despite a favourable international context, there are still serious problems of competitiveness. The region needs to increase productivity, promote technological innovation and take a proactive part in worldwide networks. The conclusions of the study include the need to update integration; to take a strategic view of the links to be constructed with China and the countries of the Pacific; to manage free-trade agreements so as to increase and diversify exports; to step up the pace of work and improve coordination with the developing countries on the Doha Round, and to gradually incorporate the demands of security into competitiveness policies, ensuring that they do not become protectionist barriers (traceability, food safety and maritime and port security).
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This issue of the FAL Bulletin contains the report prepared jointly in September 2005 by three ECLAC divisions (the Division of International Trade and Integration, the Economic Development Division and the Statistics and Economic Projections Division) on the consequences of Hurricane Katrina for the Latin American countries, especially in relation to international trade and macroeconomic impacts in the region. In addition, the web version of this issue includes two tables with data on United States imports from Latin American countries and the proportion that enters through the Port of New Orleans.
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ECLACs International Trade and Integration Division (DCII) will launch the book titled Information Technology for Development of Small and Medium-sized Exporters in Latin America and East Asia in the end of September 2005. The report provides an overview of the present condition of Information Technology (IT) and its use to promote international trade. It focuses on the experiences of IT usage by small- and medium-sized enterprises (SMEs) in the Latin American and Asian-Pacific regions, with a special focus on SME exporters in the 13 researched countries, that were selected from the Forum for East Asia - Latin America Cooperation (FEALAC) member countries. This issue of the FAL bulletin is produced based on the executive summary of the book.
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An ECLAC document to be published in the near future examines a subject that has become a frequent topic of discussion in recent years, particularly in the Southern Cone of Latin America (Argentina, Bolivia, Brazil, Chile, Paraguay, Peru and Uruguay), where the greatest volume of land transport in South America is concentrated. Against a background of economic liberalization and integration in the region, and at a time when the development of regional transport infrastructures is growing in importance, the ECLAC Transport Unit analyses the Southern Cone Agreement on International Land Transport (Valparaíso, 1989) in an effort to give it fresh relevance and to determine whether its provisions can cope with the new challenges thrown up by more open international transport markets and management.
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An international seminar-workshop entitled "Facilitation of trade and transport in Latin America: situation and outlook" was held at the headquarters of the Economic Commission for Latin America and the Caribbean (ECLAC) on 29 and 30 November 2005, organized jointly by the ECLAC Division of International Trade and Integration and the United Nations Conference on Trade and Development (UNCTAD). The event was attended by about 50 persons involved in customs modernization and/or the implementation of single window systems for foreign trade in 20 Ibero-American countries.The main purpose of the seminar-workshop was to exchange ideas, opinions and proposals concerning the efficient implementation of trade facilitation instruments. The conclusions reached at this event point to the need to seek convergence among the existing trade agreements associated with trade facilitation in Latin America. Customs modernization requires the re-design of processes and procedures in order to achieve interoperability among the systems, and single window systems for foreign trade can only be implemented successfully if clear political leadership is established with broad participation from both public and private organizations.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The routine semen evaluation assessing sperm concentration, motility and morphology, does not identify subtle defects in sperm chromatin architecture. Bulls appear to have stable chromatin, with low levels of DNA fragmentation. However, the nature of fragmentation and its impact on fertility remain unclear and there are no detailed reports characterizing the DNA organization and damage in this species. The intensive genetic selection, the use of artificial insemination and in vitro embryo production associated to the cryopreservation process can contribute to the chromatin damage and highlights the importance of sperm DNA integrity for the success of these technologies. Frozen-thawed semen samples from three ejaculates from a Nellore bull showed high levels of morphological sperm abnormalities (55.8±5.1%), and were selected for complementary tests. Damage of acrosomal (76.9±8.9%) and plasma membranes (75.7±9.3%) as well as sperm DNA strand breaks (13.8±9.5%) and protamination deficiency (3.7±0.6%) were significantly higher compared to the values measured in the semen of five Nellore bulls with normospermia (24.3±3.3%; 24.5±6.1%; 0.6±0.5%; 0.4±0.6% for acrosome, plasma membrane, DNA breaks and protamine deficiency, respectively) (P<0.05). Motility and percentage of spermatozoa with low mitochondrial potential showed no differences between groups. This study shows how routine semen analyses (in this case morphology) may point to the length and complexity of sperm cell damage emphasizing the importance of sperm function testing.