67 research outputs found

    Mytella strigata and Mytella guyanensis as an object of study: scientific and popular nomenclature review, morphological aspects and occurrence in Babitonga Bay-SC/ Mytella strigata e Mytella guyanensis como objeto de estudo: revisão da nomenclatura científica e popular, aspectos morfológicos e ocorrência na Baia da Babitonga-SC

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    Bivalve molluscs are an object of great economic interest, in the genus Mytella, it is possible to highlight the species Mytella strigata and Mytella guyanensis. The aim of this study was to carry out a review about the popular and scientific nomenclature of these species, evaluate the main characteristics used to differentiate them, as well as to carry out a quali-quantitative analysis of the mussels from the bay of Babitonga-SC. During the popular nomenclature review it turned out that the mussels M. guyanensis and M. strigata have gone through numerous revisions and nomenclature changes, as well as have several synonymous species. According to the studies reviewed to the popular nomenclature subject, 75% of the publications related to M. guyanensis and M. strigata were made in the Northeast, regarding the popular names “bacucu” and “sururu”, the second term was the most widespread. The analysis of the mussel stocks of Babitonga Bay demonstrated the predominance of M. guyanensis (96%). No significant difference was observed for the sample survey and collection station factors. However, the variations in abundance and diversity were significant for the stratum factor, where the highest values were recorded in the lower mesolittoral, suggesting a tendency for these organisms to be distributed in environments with less air exposure at low tide

    Molecular methods confirm the presence of the alien mussel Perna viridis Linnaeus, 1758 (Bivalvia, Mytilidae) in Southern Brazil

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    The mussel Perna viridis, commonly known as the green mussel, is native from the Indo-Pacific region and has been introduced in various sites around the globe. In Brazil, the species has already been recorded in Rio de Janeiro and Ceará states. With the aim of assessing the presence of mussels in the southern region of the country, 14 individuals were collected in the Paranaguá Estuarine Complex, Paraná. The mussels were found attached at a depth of 2 meters on the artificial structure of Ponta do Poço Marina. The DNA was extracted using a commercial kit, the COI gene was amplified through PCR by the primers forward dgLCO-1490 and reverse dgHCO-2198, sequenced by the Sanger method, assembled in CLC Genomics Workbench, and the species was identified through the BOLD Systems. The phylogenetic tree was built on MEGA11 using 28 sequences from three species within the genus Perna. Therefore, the present study represents the first to confirm the occurrence of the exotic species Perna viridis in Brazil through molecular identification and characterizes the third Brazilian state where the mollusk has been recorded. This indicates that Brazilian coastline provides optimal environmental conditions for the establishment and development of the P. viridisEl mejillón Perna viridis, comúnmente conocido como mejillón verde, es nativo de la región del Indo-Pacífico y ha sido introducido en varios lugares alrededor del mundo. En Brasil, la especie ya ha sido registrada en los estados de Río de Janeiro y Ceará. Con el objetivo de evaluar la presencia de mejillones en la región sur del país, se recolectaron 14 individuos en el Complejo Estuarino de Paranaguá, Paraná. Los mejillones fueron encontrados fijados a una profundidad de 2 metros en la estructura artificial de la Marina Ponta do Poço. El ADN fue extraído utilizando un kit comercial, el gen COI fue amplificado mediante PCR con los cebadores forward dgLCO-1490 y reverse dgHCO-2198, secuenciados mediante el método Sanger, ensamblados en CLC Genomics Workbench, y la especie fue identificada a través de los Sistemas BOLD. El árbol filogenético fue construido en MEGA11 utilizando 28 secuencias de tres especies dentro del género Perna. Por lo tanto, el presente estudio representa el primero en confirmar la presencia de la especie exótica Perna viridis en Brasil mediante identificación molecular y caracteriza al tercer estado brasileño donde el molusco ha sido registrado. Esto indica que el litoral brasileño proporciona condiciones ambientales ideales para el establecimiento y desarrollo del P. viridis.O mexilhão Perna viridis, comumente conhecido como mexilhão-verde, é nativo da região do Indo-Pacífico e foi introduzido em vários locais ao redor do mundo. No Brasil, a espécie já foi registrada nos estados do Rio de Janeiro e Ceará. Com o objetivo de avaliar a presença de mexilhões na região sul do país, foram coletados 14 indivíduos no Complexo Estuarino de Paranaguá, Paraná. Os mexilhões foram encontrados fixados a uma profundidade de 2 metros na estrutura artificial da Marina Ponta do Poço. O DNA foi extraído usando um kit comercial, o gene COI foi amplificado por PCR pelos primers forward dgLCO-1490 e reverse dgHCO-2198, sequenciados pelo método Sanger, montados no CLC Genomics Workbench, e a espécie foi identificada através dos Sistemas BOLD. A árvore filogenética foi construída no MEGA11 usando 28 sequências de três espécies dentro do gênero Perna. Portanto, o presente estudo representa o primeiro a confirmar a ocorrência da espécie exótica Perna viridis no Brasil através de identificação molecular e caracteriza o terceiro estado brasileiro onde o molusco foi registrado. Isso indica que o litoral brasileiro fornece condições ambientais ideais para o estabelecimento e desenvolvimento do P. viridis

    Blooms of bryozoans and epibenthic diatoms in an urbanized sandy Beach (Balneário Camboriú - SC - Brazil): dynamics, possible causes and biomass characterization

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    Balneário Camboriú (SC - Brasil) é uma cidade turística, onde o crescimento desordenado da população urbana e a implementação de obras costeiras sem uma avaliação adequada tem gerado impactos ambientais e afetado severamenteou a qualidade sanitária da água e do sedimento do rio Camboriú e da área marinha adjacente. Um dos fenômenos mais recentes e alarmantes observados são as florações de briozoários invasivos (Arboscuspis bellula e Membraniporopsis tubigera) associados com as diatomáceas epibênticas (Amphitetras antediluviana e Biddulphia biddulphiana). Vários indícios associam esses fenômenos, iniciados em 2003, com o excesso de nutrientes e matéria orgânica na enseada Camboriú e com grandes obras costeiras locais, como dragagem, aterro e construção de molhes, levando a mudanças na estrutura ecológica bêntica. Sendo um problema de estético e ambiental, a preocupação da comunidade e órgãos governamentais gerou uma intensificação nos estudos, uma vez que as ocorrências se tornaram mais frequentes e persistentes. O presente trabalho aborda este problema através de estudos ambientais e experimentais. A coleta de material bêntico com embarcação e mergulhos e monitoramento florações junto a praia compuseram a abordagem ambiental. Os trabalhos de laboratório incluíram o isolamento e a cultura de algas e brioozários, bem como a avalição do crescimento desses organismos, além da análise e avaliação química biomassa. Os dados de monitoramento mostraram uma tendência sazonal nas florações, com eventos mais evidentes nos meses mais quentes. Diatomáceas aumentaram em abundância nos meses mais frios e briozoários nos mais quentes. A diatomácea A. antediluviana, predominante nas florações, cresceu de forma satisfatória em cultivo laboratorial, mostrando um melhor crescimento em meios com concentrações mais elevadas de silicato e fosfato. Os briozoários mostraram crescimento lento em condições de laboratório. O material depositado no ambiente mostrou baixas concentrações de ácidos graxos, predominantemente saturados, mas a elevada biomassa sugere um possível uso para a produção de biocombustíveis. Amostras de biomassa dominadas por briozoários apresentaram atividade antimicrobiana moderada contra Klebsiella pneumoniae. A explicação para a ocorrência destes eventos ainda são inconclusivas, mas há evidências consideráveis de que há um efeito sinérgico entre a alta concentração de bactérias e detritos orgânicos na água, relacionada com a poluição local, e a eliminação de competidores naturais pelos impactos das obras costeiras.Balneário Camboriu (SC - Brazil) is a touristic city where the disordered growth of the urban population and the implementation of coastal works without proper evaluation generated environmental impacts and affected the sanitary quality of water and sediment of Camboriu River and marine adjacent area. One of the most recent and alarming phenomena observed are the blooms of invasive bryozoans (Arboscuspis bellula and Membraniporopsis tubigera) associated with epibenthic diatoms (Amphitetras antediluviana and Biddulphia biddulphiana). Several clues associate these phenomena, started in 2003, with the excess of nutrients and organic matter in the Camboriú cove and large coastal works such as dredging, landfills and construction of jetties, leading to changes in benthic ecological structure. Being an aesthetic and environmental health problem, the concern of the scientific community and government agencies intensified as the occurrences become more frequent and persistent. This research addresses this issue through environmental and experimental studies. Samplings of the benthic material collected by boat and diving, and blooms monitoring were the environmental approach. The laboratory work included the algal isolation and culture, in addition to growth conditions assessment and chemical biomass analysis. Monitoring data showed a seasonal trend in the blooms, with more conspicuous events in warmer months. Diatoms increase in abundance in colder months and bryozoans in the warmer ones. The diatom A. antediluviana, predominant in the blooms, grew satisfactorily in laboratory cultivation, showing better growth in media with higher concentrations of silicate and phosphate. Bryozoans showed slow growth in laboratory conditions. The deposited material collected in the environment showed low concentrations of saturated fatty acids, but the high biomass suggest a possible use for biofuels production. Biomass samples dominated by bryozoans showed moderate antimicrobial activity against Klebsiella pneumoniae. The explanation for the occurrence of these blooms are still inconclusive, but there is considerable evidence that it is a synergistic effect between the high concentration of bacteria and organic debris in the water related to local pollution and the elimination of natural competitors by coastal works

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Search for single production of vector-like quarks decaying into Wb in pp collisions at s=8\sqrt{s} = 8 TeV with the ATLAS detector

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    Measurements of top-quark pair differential cross-sections in the eμe\mu channel in pppp collisions at s=13\sqrt{s} = 13 TeV using the ATLAS detector

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    Measurement of the W boson polarisation in ttˉt\bar{t} events from pp collisions at s\sqrt{s} = 8 TeV in the lepton + jets channel with ATLAS

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    Measurement of the charge asymmetry in top-quark pair production in the lepton-plus-jets final state in pp collision data at s=8TeV\sqrt{s}=8\,\mathrm TeV{} with the ATLAS detector

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