Este estudo procura perceber até que ponto os líderes partidários portugueses utilizam as possibilidades de interação acessíveis no Twitter, nomeadamente o retweet, menção a outro utilizador e ...ligação web para outros endereços, e entender qual é a rede de ligações que é criada — se dentro do próprio partido, se aberta a protagonistas partidários de outras forças políticas ou a cidadãos. Adicionalmente, verificamos como é que, através do Twitter, os atores políticos põem em prática uma estratégia enquadrada no modelo mediático híbrido, estabelecendo ligações para os chamados “meios tradicionais de comunicação”, como jornais, rádio e televisão. Os dados são obtidos a partir de uma recolha de tweets publicados por quatro líderes partidários portugueses, do Partido Socialista, Partido Social Democrata, Bloco de Esquerda e Chega, em períodos específicos de 2021 e 2022, posteriormente sujeitos a análise de conteúdo e trabalhados informaticamente através do programa MAXQDA. A pesquisa revelou que todos os líderes utilizam as possibilidades de interação do Twitter, mas com intensidades diferentes. Verificámos que apostam numa estratégia de comunicação híbrida, fazendo convergir na plataforma do Twitter conteúdos dos média tradicionais. A partir dos dados obtidos foi possível estabelecer uma tipologia de estratégias de comunicação postas em prática pelos líderes partidários no Twitter, bem como identificar e caracterizar as possibilidades que as interações mediáticas, realizadas pelos líderes partidários, podem assumir na arena do Twitter.
This paper aims to detect railway vehicle wheel flats and polygonized wheels using an envelope spectrum analysis. First, a brief explanation of railway vehicle wheel problems is presented, focusing ...particularly on wheel flats and polygonal wheels. Then, three types of wheel flat profiles and three periodic out-of-roundness (OOR) harmonic order ranges for the polygonal wheels are evaluated in the simulations, along with analyses implemented using only healthy wheels for comparison. Moreover, the simulation implements track irregularity profiles modelled based on the US Federal Railroad Administration (FRA). From the numerical calculations, the dynamic responses of several strain gauges (SGs) and accelerometer sensors located on the rail between sleepers are evaluated. Regarding defective wheels, only the right wheel of the first wheelset is considered as a defective wheel, but the detection methodology works for various damaged wheels located in any position. The results from the application of the methodology show that the envelope spectrum analysis successfully distinguishes a healthy wheel from a defective one.
This paper presents an annotated checklist of the Basidiomycota taxa (including lichenicolous fungi and the subdivision Pucciniomycotina) from the Azores archipelago and reviews the published records ...to account for their taxonomic status. The number of Basidiomycota species recorded in the Azores has increased considerably during the 20th century and now stands at 544 species. This study provides distribution data and includes changes in the nomenclature of the listed taxa. Sampling campaigns contributed to 116 new records of Basidiomycota for the Azores archipelago. In addition, there were new records for eight islands: 162 species found for the first time on São Miguel Island, 55 species new to Santa Maria Island, 33 species new to Flores Island, 15 species new to Terceira Island, 9 species new to Pico Island, 17 species new to São Jorge Island, 4 species new to Graciosa Island, and 2 species new to Corvo Island. The transformation of vegetation cover in the archipelago has been very drastic, and this is reflected in the presence of many foreign fungal species on the islands. From these data, we conclude that within Macaronesia, the diversity of Basidiomycota in the Azores is more similar to that in Madeira than in the Canary Islands.
Cyanobacteria are among the most diverse morphological microorganisms that inhabit a great variety of habitats. Their presence in the Azores, a volcanic archipelago of nine islands in the middle of ...the North Atlantic Ocean, has already been reported. However, due to the high diversity of cyanobacteria habitats, their biodiversity is still understudied, mainly in extreme environments. To address this, a total of 156 cyanobacteria strains from Azores lakes, streams, thermal and terrestrial habitats were isolated. Identification was made based on a polyphasic approach using classical taxonomy (morphological characteristics and environmental data) and phylogeny among 81 strains assessed by maximum likelihood and Bayesian analysis of 16S rDNA partial sequences. The 156 isolates showed a high genera diversity (38) belonging to the orders Chroococcales, Nostocales, Oscillatoriales, and Synechococcales. Eleven new genera for the Azores habitats are here reported, reinforcing that cyanobacteria biodiversity in these islands is still much understudied. Phylogenetic analysis showed 14 clusters associated with these cyanobacteria orders, with evidence for six new genera and valuable information towards Microchaete/Coleospermum taxonomic revision that better reflects species environmental distribution. These results emphasize the need for cyanobacteria taxonomy revisions, through polyphasic studies, mainly in Synechococcales order and in the Microchaete/Coleospermum, Nostoc, and Anabaena genera.
Coccoid cyanobacteria represent an important part of cyanobacterial freshwater diversity, with many studied strains in public databases identified as Synechococcus. This is a diverse genus, both ...morphologically and ecologically, with a global distribution. However, many of the so-called Synechococcus-like cyanobacteria strains could represent several independent genera that require further studies. In this work, four strains of a Synechococcus-like cyanobacteria isolated from freshwater lakes and terrestrial atmophytic habitats on São Miguel and Flores Islands (Azores archipelago) were studied genetically using the 16S rRNA and 16S–23S rRNA ITS, morphologically with light and transmission electron microscopy, and ecologically. A draft genome was produced from the reference strain by Illumina sequencing, which allowed a more complete phylogenetic study and a deeper taxonomic analysis, revealing a divergent phylogenetic evolution and low ANI and AAI values (69.4% and 66.3%, respectively) to Thermosynechococcus, the closest phylogenetic genus. Although morphologically similar to Synechococcus, the 16S rRNA and genome phylogenetic analysis placed the studied strains in a clade sister to Thermosynechococcus, inside the Thermosynechococcaceae. Thus, Pseudocalidococcus azoricus gen. sp. nov. is described as a new coccoid freshwater genus and species from the Azores archipelago. A detailed comparison with similar morphological taxa is provided, supporting the separation of the new genus. The 16S rRNA with a high genetic similarity to other strains from several continents identified as Synechococcus sp. suggests that the new genus probably has a worldwide distribution. Future studies should be performed to clarify the taxonomic identity of those strains.
Eutrophication and global climate change gather advantageous conditions for cyanobacteria proliferation leading to bloom formation and cyanotoxin production. In the Azores, eutrophication is a major ...concern, mainly in lakes where fertilizers and organic matter discharges have increased nutrient concentration. In this study, we focused on understanding the influence of environmental factors and lake characteristics on (i) cyanobacteria diversity and biomass and (ii) the presence of toxic strains and microcystin, saxitoxin, anatoxin-a, and cylindrospermopsin cyanotoxin-producing genes. Fifteen lakes from the Azores Archipelago were sampled seasonally, environmental variables were recorded in situ, cyanobacteria were analyzed with microscopic techniques, and cyanotoxin-producing genes were targeted through conventional PCR. Statistical analysis (DistLM) showed that lake typology-associated variables (lake’s depth, area, and altitude) were the most explanatory variables of cyanobacteria biomass and cyanotoxin-producing genes presence, although trophic variables (chlorophyll a and total phosphorus) influence species distribution in each lake type. Our main results revealed higher cyanobacteria biomass/diversity, and higher toxicity risk in lakes located at lower altitudes, associated with deep anthropogenic pressures and eutrophication scenarios. These results emphasize the need for cyanobacteria blooms control measures, mainly by decreasing anthropogenic pressures surrounding these lakes, thus decreasing eutrophication. We also highlight the potential for microcystin, saxitoxin, and anatoxin-a production in these lakes, hence the necessity to implement continuous mitigation protocols to avoid environmental and public health toxicity events.
Knowledge about cyanobacteria diversity in the Azores is spread over several publications, dating from 1874, with some of them not generally available to the scientific community due to their ...restricted access. The dispersion and sometimes inaccessibility of this information hinder a deeper analysis and a better understanding of the biodiversity of the Azores Islands and more general ecological processes in oceanic islands. Here we present the first checklist of cyanobacteria for the Azores Archipelago with updated taxonomy of all recorded taxa.
This work provides a compiled and annotated checklist of all known cyanobacteria from the Azores Archipelago with morphological identification from preserved samples and cultures, based on published literature. All records of taxa known to occur in the Azores were taxonomically updated. The present checklist comprises 225 taxa distributed by six orders (Chroococcales, Nostocales, Oscillatoriales, Pleurocapsales, Spirulinales and Synechococcales). Our literature review reveals that the Azores Archipelago hosts a high diversity of cyanobacteria, despite several overlooked habitats that may present great potential regarding cyanobacteria diversity. Increasing efforts to study these neglected habitats could contribute to the knowledge of cyanobacteria taxonomy. This checklist provides the basis for future works on the taxonomy and taxa richness of cyanobacteria in the Azores and the Atlantic Islands, as also for understanding and monitoring non-indigenous and invasive species.
Microcystins (MCs), Saxitoxins (STXs), and Cylindrospermopsins (CYNs) are some of the more well-known cyanotoxins. Taking into consideration the impacts of cyanotoxins, many studies have focused on ...the identification of unknown cyanotoxin(s)-producing strains. This study aimed to screen strains from the Azorean Bank of Algae and Cyanobacteria (BACA) for MCs, STX, and CYN production. A total of 157 strains were searched for
,
and
producing genes by PCR, toxin identification by ESI-LC-MS/MS, and cyanotoxin-producing strains morphological identification and confirmation by 16S rRNA phylogenetic analysis. Cyanotoxin-producing genes were amplified in 13 strains and four were confirmed as toxin producers by ESI-LC-MS/MS. As expected
BACA0041 was confirmed as an STX producer, with amplification of genes
A,
G,
H, and
I, and
BACA0148 as an MC-LR producer, with amplification of genes
C,
D,
E, and
G. Two nostocalean strains, BACA0025 and BACA0031, were positive for both
B and
C genes and ESI-LC-MS/MS confirmed CYN production. Although these strains morphologically resemble
, the 16S rRNA phylogenetic analysis reveals that they probably belong to a new genus.
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