132 resultados para Elastomeric chain
Resumo:
This work determined toxicity and attractiveness of straight-chain fatty acids (C 5 to C 12) to Atta sexdens rubropilosa (Forel) workers. The effect to the symbiotic fungus, Leucoagaricus gongylophorus (Singer) Möller, was also tested with the fatty acids C 6 to C 12. A strong mortality of leaf-cutting ants that were fed with an artificial diet containing fatty acids C to C at concentrations above 1.0 mg.ml -1 was observed. Rice flakes impregnated with solutions of these fatty acids were repellent to leaf-cutting ants. Contact experiments showed that treatments with C 6 and C 7 at concentration of 100 mg.ml -1 significantly reduced the survival rate of leaf-cutting ants. The fatty acids C 8 to C 11 were toxic to leaf-cutting ants when topically tested at concentration of 200 mg.ml -1. In relation to the fungus' bioassays, the fatty acids C 6 to C 12 at concentration of 0.1 mg.ml -1 inhibited 100% of the fungal development. Although when the concentration was reduced by half no inhibition effects were observed. The results showed that straight-chain fatty acids have desirable properties for controlling leaf-cutting ants since they directly interfere with both organisms of the symbiotic relationship. The potential of fatty acids as well as ways to control leaf-cutting ants with these compounds are discussed in this article.
Resumo:
In the present study, we evaluated three techniques, mouse bioassay, histopathology, and polymerase chain reaction (PCR) to detect Toxoplasma gondii infection in tissues from experimentally infected pigs. Twelve mixed breed pigs, seronegative for T. gondii using an indirect immunofluorescent antibody test (IFAT), were used. Ten pigs were infected with 4 × 104 VEG strain oocysts, and two were maintained as uninfected controls. Animals were killed 60 days pos infection. Muscle (heart, tongue, diaphragm, and masseter) and brain samples were collected to investigate the presence of T. gondii tissue cysts by the different assay methods. For the bioassay, samples of brain (50 g) and pool of muscle samples (12.5 g of tongue, masseter, diaphragm, and heart) were used. PCR was performed using Tox4 and Tox5 primers which amplified a 529 bp fragment. The DNA extraction and PCR were performed three times, and all tissue samples were tested individually (brain, tongue, masseter, diaphragm, and heart). For histopathology, fragments of tissues were fixed in 10% of buffered formal saline and stained with HE. Histopathological results were all negative. PCR showed 25/150 (16.6%) positive samples, being 17/120 (14.1%) and 8/30 (26.6%) from muscle, and brain tissues, respectively. Tissue cysts of T. gondii were identified by mouse bioassay in 54/98 (55.1%) samples, being 31/48 (64.6%) from muscle samples, and 23/50 (46.0%) from brain samples. Toxoplasma gondii isolation in muscle samples by mouse bioassay was higher than in PCR (P < 0.01). Results indicate that DNA from pig tissues interfered with 529-bp-PCR sensitivity, and mouse bioassay was better than PCR in detecting T. gondii in tissues from pigs. © 2006 Elsevier Inc. All rights reserved.
Resumo:
The purposes of this study were to detect S. mutans and S. sobrinus by polymerase chain reaction (PCR) amplification, and to relate their presence to the incidence of dental caries in 42 Brazilian preschool children. Dental plaque samples were collected from the cervical margin of all erupted teeth of 5-6 years old children with primary dentition, using a sterile explorer. Examination of the dmft (decayed, missing, filled teeth) index, performed following the World Health Organization (WHO) caries diagnostic criteria, showed a 2.71 score. Prevalence of S. mutans and S. sobrinus was respectively, of 85.7% and 14.3%; no dental plaque sample was either positive or negative for both bacterial species. Children harboring either S. mutans or S. sobrinus presented the same caries prevalence. PCR showed good discriminative ability for differentiation between these species, and suggested that it is a technique suitable for epidemiological studies on mutans streptococci.
Resumo:
Background. The use of methods, both sensitive and specific, for rabies diagnosis are important tools for the control and prophylaxis of the disease. Reverse-Transcriptase Polymerase Chain Reaction (RT-PCR) has been used in rabies diagnosis with good results, even in decomposed materials. Additionally, molecular techniques have been used for epidemiological studies and to gain a better knowledge of viral epidemiology. Findings. The aim of this work was to evaluate the RT-PCR and hnRT-PCR for rabies virus detection in original tissues stored at -20°C for different periods considering their use for rabies virus detection in stored and decomposed samples. RT-PCR and hnRT-PCR were evaluated in 151 brain samples from different animal species, thawed and left at room temperature for 72 hours for decomposition. The RT-PCR and hnRT-PCR results were compared with previous results from Direct Fluorescent Antibody Test and Mouse Inoculation Test. From the 50 positive fresh samples, 26 (52%) were positive for RT-PCR and 45 (90%) for hnRT-PCR. From the 48 positive decomposed samples, 17 (34, 3%) were positive for RT-PCR and 36 (75%) for hnRT-PCR. No false-positives results were found in the negatives samples evaluated to the molecular techniques. Conclusion. These results show that the hnRT-PCR was more sensitive than RT-PCR, and both techniques presented lower sensibility in decomposed samples. The hnRT-PCR demonstrated efficacy in rabies virus detection in stored and decomposed materials suggesting it's application for rabies virus retrospective epidemiological studies. © 2008 Arajo et al; licensee BioMed Central Ltd.
Resumo:
Purpose: This paper aims to perform an empirical investigation about the constructs and indicators of the supply chain management practices framework. Design/methodology/approach: The measuring framework proposed is based on a survey that was carried out on 107 Brazilian companies. Statistical techniques were employed to verify, validate, and test the reliability of the constructs and their indicators. To validate this framework principal component analysis and structural equation modeling techniques were used. Findings: In general, previous studies suggest six constructs for measuring the supply chain management practices framework. However, in this study a framework was achieved with four constructs of supply chain management practices, namely, supply chain (SC) integration for production planning and control (PPC) support, information sharing about products and targeting strategies, strategic relationship with customer and supplier, and support customer order. This framework has adequate levels of validity and reliability. Research limitations/implications: The main limitation of this study was that only a small sample of companies in a single sector and country were surveyed, and therefore there needs to be further research considering the special conditions in other countries. Originality/value: This study investigated statistically set indicators to discuss the topic supply chain management practices. The framework obtained has good quality of validity and reliability indicators. Thus, an alternative framework has been added to measure supply chain management practices, which is currently a popular topic in the supply chain mainstream literature. Both defined constructs and the validated indicators can be used in other studies on supply chain management. © Emerald Group Publishing Limited.
Resumo:
This paper aimed to analyse supply chain risk factors in aerospace industry. It was conducted an exploratory research at an important Brazilian aerospace company. This company has a major role at the global aerospace industry. Senior managers assessed risk factors such as quality, productivity, supply chain, business strategy, organisation, environmental and natural political, indicators, product management, and information system. Analytic hierarchy process was applied to prioritise these factors. The most relevant were quality and productivity. Copyright © 2011 Inderscience Enterprises Ltd.
Resumo:
This study on the factors affecting the adoption of supply chain management (SCM) practices develops four hypotheses based on a literature review, and tests them using survey data of Brazilian electro-electronic firms. The results reveal the big picture of the SCM practices in the sector and suggest that contextual factors such as size, position and bargaining power affect the adoption of SCM practices, which are also more customer oriented. Sector characteristics are very important in analysing SCM practices. Contrary to the findings of literature, the relationship between competitive priorities and SCM practices was not supported statistically. © 2011.
Resumo:
The objective of this study is to understand how an assembly company, that is considered a focal company in the chain of Brazilian white goods sector, can influence the supply chain management established with its first tier suppliers. This is an exploratory qualitative study in which the information was gathered through direct observations, documents' retention, and data from interviews held with management-level employees of the sales and product development areas of the focal company and of the production area of the suppliers' companies. This study indicates that the operations strategy of the focal company influences the supply chain management and that the common business processes shared by its suppliers are a way to verify the truth of such statement. The suppliers cooperate closely with the focal company when complementing their business processes and consequently supporting the company to pursue its operations strategy. A set of mechanisms to aid the comprehension of how the operations strategy can affect the business processes and therefore to achieve the result of this research were adopted. © EuroJournals Publishing, Inc. 2012.
Resumo:
This paper examines the current level of adoption of Supply Chain Management (SCM) practices in the electro-electronic sector in Brazil and aims to identify the management and Information Technology (IT) actions that have been implemented to support the adoption of those practices. An e-mail survey was conducted. Descriptive statistics techniques were employed for data analysis. This study makes contributions to the electro-electronics sector and to the topics related to SCM, such as identifi cation and level of adoption of SCM practices. Another contribution of this research is the investigation of whether approaches such as Enterprise Resources Planning (ERP), Workshop with Customers, Electronic Data Interchange (EDI), Workshop with Suppliers and electronic Kanban are commonly used to support SCM practices. So far, this is the fi rst research on SCM practices in the electro-electronics sector in Brazil. Copyright © 2012 Inderscience Enterprises Ltd.
Resumo:
The aim of this study was to evaluate a simple molecular method of reverse transcriptase polymerase chain reaction (RT-PCR) to differentiate Newcastle disease virus strains according to their pathogenicity, in order to use it in molecular screening of Newcastle disease virus in poultry and free-living bird populations. Specific primers were developed to differentiate LaSota-LS-(vaccine strain) and Sao Joao do Meriti-SJM-strain (highly pathogenic strain). Chickens and pigeons were experimentally vaccinated/infected for an in vivo study to determine virus shedding in feces. Validation of sensitivity and specificity of the primers (SJM and LS) by experimental models used in the present study and results obtained in the molecular analysis of the primers by BLAST made it possible to generalize results. The development of primers that differentiate the level of pathogenicity of NDV stains is very important, mainly in countries where real-time RT-PCR is still not used as a routine test. These primers were able to determine the presence of the agent and to differentiate it according to its pathogenicity. © 2012 Springer Science+Business Media B.V.
Resumo:
Salmonella Pullorum and Salmonella Gallinarum are classified as biovars of Salmonella enterica subsp. enterica serovar Gallinarum. These salmonellae are the causative agents of Pullorum disease and fowl typhoid, respectively, and are widely distributed throughout the world. Although many developed countries have eradicated these diseases from commercial poultry, they are still the cause of significant economic loss in developing countries. When serovar Gallinarum is isolated, it is difficult to immediately differentiate between biovars because they are antigenically identical by serotyping. However, they cause distinct diseases with different epidemiology, and therefore it is important to differentiate them. This may be done biochemically but takes 2 to 3 days. In the present study, S. Pullorum and S. Gallinarum whole genomes were compared, and 1 genomic region of difference, which is part of the ratA gene, was chosen as a molecular marker for a polymerase chain reaction assay to differentiate rapidly between these organisms. In all, 26 strains of S. Gallinarum and 17 S. Pullorum strains were tested and successfully differentiated by the assay. © 2013 The Author(s).
Resumo:
The aim of this study is to identify and analyse the factors that affect the adoption of Green Supply Chain Management practices based on empirical evidence from the Brazilian electronics sector. Data are collected in a survey of 100 electronics companies and analysed using statistical analysis of variance and regression methods. The study finds that the size of the company, previous experience with Environmental Management Systems, and the use of hazardous inputs are positively correlated with GSCM practices adoption. Surprisingly, formal pressure from the stronger tier/player in the supply chain is not correlated with the adoption of GSCM practices. Finally, we present some explanations for these findings and suggestions for future research. © 2013 Copyright Taylor and Francis Group, LLC.
Resumo:
The objective of this article is to analyse how green supply chain management (GSCM) practices are being adopted by some high-tech companies located in Brazil. The research was conducted using the case study approach, focusing on eight companies that are representative of this sector. The main results are: (a) the most adopted GSCM practices in the studied high-tech companies located in Brazil are internal environmental management, investment recovery and reverse logistics and (b) Brazilian environmental legislation and international policies are very important in driving the adoption of GSCM practices. The internationalisation of companies was also found to be a variable that interferes with the adoption of GSCM practices. This is one of the first studies that examine the relationship between GSCM and the internationalisation of companies located in Brazil. © 2013 Springer-Verlag London.
Resumo:
The objective of this paper is to identify the main definitions, related practices and to point out future directions in green supply chain management (GSCM). After a literature review and systematisation of the published articles in this field, it was possible to identify: a) the main research objectives of analysed papers; b) the research methods adopted; c) the predominantly analysed industrial sectors; d) the GSCM practices considered by the researchers. Results are presented in each of these analytical perspectives. The main findings are: 1) there are various classifications, nomenclatures and types of GSCM practices, but the most commonly used by studies in GSCM are cleaner production, product design, reverse logistic and green purchasing; 2) from the highlighted definitions, the tonic is to adapt operating activities and incorporate the supply chain management philosophy (integration/ collaboration) to environmental concerns (impact reduction) in relations between links in the chain. These results can be useful for those interested in environmental management as well as supply chain management, considering the growing interest in GSCM. We also propose a research agenda on this subject. This is one of the most recent literature review and systematisation on green supply chain management. © 2013 Inderscience Enterprises Ltd.
Resumo:
Industries need to adopt the environmental management concepts in the traditional supply chain management. The green supply chain management (GSCM) is an established concept to ensure environment-friendly activities in industry. This paper identifies the relationship of driving and dependence that exists between GSCM practices with regard to their adoption within Brazilian electrical/electronic industry with the help of interpretive structural modelling (ISM). From the results, we infer that cooperation with customers for eco-design practice is driving other practices, and this practice acts as a vital role among other practices. Commitment to GSCM from senior managers and cooperation with customers for cleaner production occupy the highest level. © 2013 Copyright Taylor and Francis Group, LLC.