930 research outputs found

    Bacterial and microeukaryotic plankton communities in a semi-intensive aquaculture system of sea bass (Dicentrarchus labrax): a seasonal survey

    Get PDF
    The importance of microbial diversity and their role in the maintenance of fish health in aquaculture systems has been increasingly recognized in recent years. However, there is still a major knowledge gap regarding the ecology, composition and dynamics of microbial plankton assemblages during fish production. In this study, we aimed to investigate the seasonal dynamics and potential interactions of bacterial and microeukaryotic plankton communities in a semi-intensive aquaculture for European sea bass (Dicentrarchus labrax) cultured together with low density of gilthead sea bream (Sparus aurata) over a one-year period (January/2014 – November/2014). While the most abundant bacterial classes were Gammaproteobacteria, Flavobacteriia and Alphaproteobacteria; microeukaryotic communities were dominated by Ochrophyta, Chlorophyta and Ciliophora groups. Temperature and salinity were identified as significant drivers of the overall microbial community composition, which varied congruently along the seasons. However, while the dominant (more abundant) groups of bacteria occurred in the warmest months, the dominant groups of microeukaryotes occurred in the coldest months. There was also an inverse relationship between abundances of grazers and bacterial operational taxonomic units (OTUs). Overall, besides the potential effects of the abiotic parameters on the microbial plankton communities, the correlation between bacteria and microeukaryotic populations observed here may be an indication of trophic and/or metabolic interdependence between these two domains. Future studies should focus on the underlying mechanisms of this interdependence for a better understand of the impact of microeukaryotic communities on aquaculture bacterioplankton structure and function. In addition, this knowledge could be of interest in the development of microbial management strategies for aquaculture systems.publishe

    Energy budgets for juvenile Pacific whiteleg shrimp Litopenaeus vannamei fed different diets

    Get PDF
    Energy budgets for juvenile Pacific whiteleg shrimp, Litopenaeus vannamei (1.7-4.0 g ) fed with different diets were assessed. The energy partitioning between growth, respiration, ammonia excretion, feces and exuvia was calculated to estimate for total food energy intake. Shrimp oxygen consumption and ammonia excretion were quantified in sealed chambers (25°C, 34 ppt). Energy allocated for growth and feces were obtained from the wet combustion of whole body and feces samples, exuvia was estimated as 10% growth energy. Three diets were tested: 100% chopped fish (Fish), 100% commercial feed (Feed), and 50-50% chopped fish and commercial feed (Mix). Most of the energy from the diets was channeled into respiration (49.7-70.5%). Shrimp fed the Feed diet used more energy in growth (24.4%) than those fed Mix (13.4%) or Fish diets (13.2%), either in absolute (joule) or relative (% of ingested energy) terms. Conversely, energy loss as ammonia excretion was lower in shrimp fed Feed (1.0%) compared to shrimp fed Mix (4.2%) or Fish diets (7.8%). Less energy was lost in feces by shrimp fed Fish diet (7.3%) compared to Mix (20.2%) and Feed diets (22.2%). The calculated energy intake by shrimp fed Fish, Mix and Feed were 0.995, 1.100, and 1.255 kJ ind-1day-1, respectively. According to the O:N atomic ratios (oxygen consumed to nitrogen excreted), protein tented to be the predominant substrate catabolized by shrimp fed Fish (O:N=16±5.2), and Mix (O:N=25±11.6), with increasing use of carbohydrates and/or lipids in the Feed (O:N=74±37.3). Results suggest diet composition may affect energy budget and partitioning differently between metabolism and growth either in absolute or relative terms, as shrimp fed Fish and Mix diets used protein as main substrate for metabolism, whereas shrimp fed Feed diet channeled protein for growth, and lipids and carbohydrates for other metabolic functions

    Zika is not a reason for missing the Olympic Games in Rio de Janeiro: response to the open letter of Dr Attaran and colleagues to Dr Margaret Chan, Director - General, WHO, on the Zika threat to the Olympic and Paralympic Games.

    Get PDF
    Attaran and colleagues in an open letter to WHO expressed their concern about the upcoming Olympic and Paralympic Games in Rio de Janeiro and the threat posed by the Zika epidemic (Attaran 2016). We agree that Zika virus is of great public health concern and much remains to be known about this disease. Care should be taken to reduce the risk of infection, especially to pregnant women. However, we argue that this is not sufficient reason for changing the original plans for the Games, in particular because of the time of the year when they will take place. The present article outlines several scientific results related to Zika and mosquito-borne infectious diseases dynamics that we believe ratify the current position of WHO in not endorsing the postponing or relocation of the 2016 Olympic and Paralympic Games (WHO 2016)

    Web modelling for web warehouse design

    Get PDF
    Tese de doutoramento em Informática (Engenharia Informática), apresentada à Universidade de Lisboa através da Faculdade de Ciências, 2007Users require applications to help them obtaining knowledge from the web. However, the specific characteristics of web data make it difficult to create these applications. One possible solution to facilitate this task is to extract information from the web, transform and load it to a Web Warehouse, which provides uniform access methods for automatic processing of the data. Web Warehousing is conceptually similar to Data Warehousing approaches used to integrate relational information from databases. However, the structure of the web is very dynamic and cannot be controlled by the Warehouse designers. Web models frequently do not reflect the current state of the web. Thus, Web Warehouses must be redesigned at a late stage of development. These changes have high costs and may jeopardize entire projects. This thesis addresses the problem of modelling the web and its influence in the design of Web Warehouses. A model of a web portion was derived and based on it, a Web Warehouse prototype was designed. The prototype was validated in several real-usage scenarios. The obtained results show that web modelling is a fundamental step of the web data integration process.Os utilizadores da web recorrem a ferramentas que os ajudem a satisfazer as suas necessidades de informação. Contudo, as características específicas dos conteúdos provenientes da web dificultam o desenvolvimento destas aplicações. Uma aproximação possível para a resolução deste problema é a integração de dados provenientes da web num Armazém de Dados Web que, por sua vez, disponibilize métodos de acesso uniformes e facilitem o processamento automático. Um Armazém de Dados Web é conceptualmente semelhante a um Armazém de Dados de negócio. No entanto, a estrutura da informação a carregar, a web, não pode ser controlada ou facilmente modelada pelos analistas. Os modelos da web existentes não são tipicamente representativos do seu estado presente. Como consequência, os Armazéns de Dados Web sofrem frequentemente alterações profundas no seu desenho quando já se encontram numa fase avançada de desenvolvimento. Estas mudanças têm custos elevados e podem pôr em causa a viabilidade de todo um projecto. Esta tese estuda o problema da modelação da web e a sua influência no desenho de Armazéns de Dados Web. Para este efeito, foi extraído um modelo de uma porção da web, e com base nele, desenhado um protótipo de um Armazém de Dados Web. Este protótipo foi validado através da sua utilização em vários contextos distintos. Os resultados obtidos mostram que a modelação da web deve ser considerada no processo de integração de dados da web.Fundação para Computação Científica Nacional (FCCN); LaSIGE-Laboratório de Sistemas Informáticos de Grande Escala; Fundação para a Ciência e Tecnologia (FCT), (SFRH/BD/11062/2002

    Burkholderia pseudomallei: primeiro caso de melioidose em Portugal

    Get PDF
    Objetivo: Este estudo apresenta o primeiro caso de melioidose em Portugal, revelando o importante papel da metodologia de Sequenciação Total do Genoma para a correta identificação e caracterização da estirpe isolada

    Prevalence of antibiotic (ß-lactams, tetracycline, metronidazole, erythromycin) resistance genes in periodontic infections

    Get PDF
    Objective: Porphyromonas gingivalis and Prevotella intermedia are thought to be pathogens in adult periodontitis. Antibiotherapy is usually needed in the treatment of periodontitis being often prescribed empirically. To allow prescription of a specific antibiotic treatment, identification of resistance genes should be performed. The aim of this study was the identification of the presence of TetM, TetQ, TEM, cfxA, MefA, ErmB and Nim resistance genes in previously identified P. intermedia and P. gingivalis isolated from samples collected from periodontal infections. Method: PCR was used for the identification of TetM, TetQ, TEM, cfxA, MefA, ErmB and Nim resistance genes in strains isolated from samples collected from periodontal infections. Results: It was seen that 8% of isolates had one of the tested tetracycline resistance genes. A total of 32% of β-lactamases resistance genes was observed in isolated strains. It was also observed that 2% of isolates had one of the analysed erythromycin resistance genes. None of the isolates showed the presence of the metronidazole resistance gene. Conclusions: Most strains harboring β-lactamase resistance genes had been previously identified as P. intermedia. No tetracycline resistance gene and a very low percentage of β-lactamase resistance genes were observed in P. gingivalis strains.info:eu-repo/semantics/publishedVersio

    Distribution extension of Amphisbaena lumbricalis Vanzolini, 1996 with its first predation record by snake Erythrolamprus viridis (Günther, 1862)

    Get PDF
    We expand the geographical distribution of Amphisbaena lumbricalis throughout the first record for a semiarid Caatinga area in the Paraíba state, northeastern Brazil. Furthermore, we report the first predation report of A. lumbricalis by the snake Erythrolamprus viridis. Our findings contribute with information about the habitats occupied by a hitherto considered “Data Deficient” species, beyond to reveal the potential of E. viridis to prey upon reptiles.Asociación Herpetológica Argentin

    Cognitive effects of the progressive exercise test in electricians wearing personal protective equipment.

    Get PDF
    Objetivo: verificar o efeito do esfor?o f?sico sobre as fun??es cognitivas de trabalhadores eletricistas utilizando equipamento de prote??o individual (EPI). M?todos: participaram 28 eletricistas que trabalhavam na constru??o, manuten??o e opera??o de redes de distribui??o de energia. Todos do sexo masculino, sadios e aptos para a pr?tica de exerc?cios f?sicos. As fun??es cognitivas foram representadas pelo teste de rea??o simples (TRS) e pelo n?vel de vigil?ncia mental (NVM). O TRS e o NVM foram mensurados pr? e p?s- -teste m?ximo progressivo, em esteira rolante, a 27 ?C de temperatura seca e umidade relativa do ar de 64%. O teste consistiu em aumentos progressivos na velocidade e na inclina??o da esteira at? a fadiga, com utiliza??o de EPI. Resultados: a m?dia (desvio padr?o) do TRS n?o foi significativamente diferente antes, 227,8 (35,1) ms, e ap?s o exerc?cio, 220,6 (24,6) ms. O NVM foi significativamente maior ap?s o exerc?cio em todas as situa??es: frequ?ncia crescente ? 36,5 (5,1) Hz vs 39,5 (2,7) Hz, frequ?ncia decrescente ? 36,0 (5,2) vs 39,0 (3,88) Hz, e frequ?ncia geral ? 36,2 (4,9) vs 39,2 (3,1) Hz. Conclus?o: o exerc?cio progressivo m?ximo realizado com EPI n?o modificou o tempo de rea??o simples e aumentou o n?vel de vigil?ncia mental de eletricistas.Objective: to verify the effects of physical effort on the cognitive functions of electricians wearing personal protective equipment (PPE). Methods: 28 electricians participated. They worked on the construction, maintenance and operation of electrical power distribution networks. All were male, healthy and able to practice physical exercises. The cognitive functions were checked by measuring simple reaction time (SRT) and mental alertness level (MAL). SRT and MAL were measured before and after progressive maximal exercise, on a treadmill, at 27 ?C dry temperature and 64% relative humidity, wearing PPE. The test consisted of progressive increases in treadmill speed and incline, until fatigue. Results: SRT mean difference was not significantly different before ? 227.8 (35.1) ms ? and after exercising ?220.6 (24.6) ms. MAL was significantly higher after exercise in all situations: increasing frequency - 36.5 (5.1) Hz vs. 39.5 (2.7) Hz; decreasing frequency-36.0 (5.2) Hz vs. 39.0 (3.88) Hz; and general frequency 36.2 (4.9) Hz vs. 39.2 (3.1) Hz. Conclusion: progressive maximal exercise performed while wearing PPE caused no change in simple reaction time, and increased electricians? mental alertness level

    Tunable magnetocaloric effect around room temperature by Fe doping in Mn0.98Cr(0.02-x)FexAs compound

    Get PDF
    In this work, we present an investigation of the magnetic and magnetocaloric properties of Mn0.98Cr(0.02-x)FexAs compounds with x = 0.002, 0.005 and 0.010. Our findings show that as Fe content increases the unit cell volume decreases, which indicates that Fe doping emulates the pressure effect on the crystalline structure. The transition temperature TC decreases as x increases and it can be set at approximate value of room temperature by changing the doping level. In addition, the magnetic entropy change ΔSM was determined using a discontinuous measurement protocol, and realistic values from the magnetocaloric effect presented by MnAs-type compounds under pressure (emulated pressure) could be obtained. The values of ΔSMMAX are very large, around −11 Jkg−1K−1 with ΔH = 15 kOe, which is higher than that observed for most compounds with TC around room temperature. However, ΔSM is confined to a narrow temperature range of 11 K. To overcome this drawback, the composition of a theoretical composite formed by our samples was calculated in order to obtain a table-shaped ΔSM curve. The simulated composite showed a high value of full width at half maximum δTFWHM of 33 K, which is much higher than that of single sample.Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro - FAPERJ E-26/110.393/2014, E-16/210.263/2014Coordenação de aperfeiçoamento de pessoal de nivel superior - CAPES 485200/2013-9Fundación de Apoyo a la Investigación del Estado de São Paulo - FAPESP 2012/03480-0Ministerio de Economía y Competitividad MAT2013-45165-
    corecore