10 research outputs found

    Hydrodynamic signatures and spectral properties of the quantum vortex

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    We characterize the low-lying excitations of a quantum vortex in a quasi-two-dimensional Bose-Einstein condensate (BEC) using the standard definition of the density of states (DOS) and a modified version that is sensitive to complementary aspects of the excitation's spectrum. The latter proves to be particularly relevant to studying the polaronic state realized when an impurity is embedded in a quantum vortex. We establish that the impurity becomes sensitive to the transversal fluctuations of the vortex, via its remnant kelvon mode, and to the phase fluctuations of the BEC Nambu-Goldstone mode. The presence of the vortex yields an anomalous excitation spectrum with a finite energy gap and non-linear DOS at low energies. We find that the high sensitivity of the kelvon mode to external potentials provides a channel of quantum-level control over impurities trapped in a vortex. This extra control channel may be of practical use for the proposal of using vortex-trapped impurities as qubit units for quantum information processing.Comment: (v. 2) Changes in the language and structure of the abstract, introduction and conclusion; minimal change in the title. Typos corrected; slight change in nomenclature (incl. figures) in the main body of the text. References adde

    Jeje: repensando naçÔes e transnacionalismo

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    Composição florística do estrato arbóreo de floresta Atlùntica Interiorana em Araponga - Minas Gerais Tree strtum floristc composition of an Inland Atlantic forest in Araponga - MG

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    Os objetivos deste trabalho foram determinar a composição florĂ­stica de um fragmento de Floresta e analisar a sua similaridade com outras ĂĄreas de Floresta Estacional Semidecidual e Floresta OmbrĂłfila Densa, com o intuito de classificar a tipologia florestal da ĂĄrea de estudo. O levantamento foi realizado em uma trilha interpretativa na Pousada Serra D'Água (20Âș41'24"S e 42Âș29'47"W, 1.100 m de altitude), regiĂŁo de entorno do Parque Estadual da Serra do Brigadeiro (PESB), MunicĂ­pio de Araponga, MG. A listagem florĂ­stica foi obtida a partir do levantamento fitossociolĂłgico, no qual foram demarcados 150 pontos quadrantes. Foram relacionadas 147 espĂ©cies, 98 gĂȘneros e 50 famĂ­lias. As famĂ­lias com maior nĂșmero de espĂ©cies foram: Melastomataceae (14), Leguminosae (11), Myrtaceae (10), Rubiaceae (8), Annonaceae (7), Flacourtiaceae (7), Lauraceae (7) e Meliaceae (6). Os resultados da anĂĄlise de agrupamento revelaram que os aspectos de proximidade geogrĂĄfica e altitude sĂŁo os principais responsĂĄveis pela similaridade florĂ­stica de muitas ĂĄreas. A vegetação da ĂĄrea de estudo pode ser classificada como Floresta Estacional Semidecidual Montana, pelo fato de a sua composição florĂ­stica mostrar alta similaridade com outras ĂĄreas dessa mesma tipologia.<br>The objective of this work was to determine the floristic composition of a forest fragment and to analyze its similarity with other areas of the Semideciduous Seasonal Forest and Dense Ombrophylous Forest, in order to classify the forest typology of this area. The survey was carried out in an interpretative trail at the Pousada Serra D'Água (20Âș41'24"S and 42Âș29'47"W, 1100 m altitude), in the region around the Serra do Brigadeiro State Park (PESB), municipality of Araponga, MG. The floristic list was obtained from the phytosociological survey in which 150 quarter-centered-points were established. A total of 147 species, 98 genera and 50 families were found. The families with the greatest number of species were: Melastomataceae (14), Leguminosae (11), Myrtaceae (10), Rubiaceae (8), Annonaceae (7), Flacourtiaceae (7), Lauraceae (7) and Meliaceae (6). The results of the cluster analysis showed that the aspects of geographic proximity and altitude are the main factors responsible for the floristic similarity of many areas. The vegetation of the studied area can be classified as Montane Semideciduous Seasonal Forest, since its floristic composition shows a great similarity with other areas of the same typology

    Floristic survey of vascular plants of a poorly known area in the Brazilian Atlantic Forest (Flona do Rio Preto, EspĂ­rito Santo)

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    The Atlantic Forest is one of the most threatened biomes in the world. Despite that, this biome still includes many areas that are poorly known floristically, including several protected areas, such as the "Floresta Nacional do Rio Preto" ("Flona do Rio Preto"), located in the Brazilian State of Espírito Santo. This study used a published vascular plant species list for this protected area from the "Catålogo de Plantas das Unidades de Conservação do Brasil" as the basis to synthesise the species richness, endemism, conservation and new species occurrences found in the "Flona do Rio Preto".The published list of vascular plants was based on field expeditions conducted between 2018 and 2020 and data obtained from herbarium collections available in online databases. Overall, 722 species were documented for the "Flona do Rio Preto", 711 of which are native to Brazil and 349 are endemic to the Atlantic Forest. In addition, 60 species are geographically disjunct between the Atlantic and the Amazon Forests. Most of the documented species are woody and more than 50% of these are trees. Twenty-three species are threatened (CR, EN and VU), while five are Data Deficient (DD). Thirty-two species are new records for the State of Espírito Santo. Our results expand the knowledge of the flora of the Atlantic Forest and provide support for the development of new conservation policies for this protected area

    An insight into the transcriptome of the digestive tract of the bloodsucking bug, Rhodnius prolixus.

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    The bloodsucking hemipteran Rhodnius prolixus is a vector of Chagas' disease, which affects 7-8 million people today in Latin America. In contrast to other hematophagous insects, the triatomine gut is compartmentalized into three segments that perform different functions during blood digestion. Here we report analysis of transcriptomes for each of the segments using pyrosequencing technology. Comparison of transcript frequency in digestive libraries with a whole-body library was used to evaluate expression levels. All classes of digestive enzymes were highly expressed, with a predominance of cysteine and aspartic proteinases, the latter showing a significant expansion through gene duplication. Although no protein digestion is known to occur in the anterior midgut (AM), protease transcripts were found, suggesting secretion as pro-enzymes, being possibly activated in the posterior midgut (PM). As expected, genes related to cytoskeleton, protein synthesis apparatus, protein traffic, and secretion were abundantly transcribed. Despite the absence of a chitinous peritrophic membrane in hemipterans - which have instead a lipidic perimicrovillar membrane lining over midgut epithelia - several gut-specific peritrophin transcripts were found, suggesting that these proteins perform functions other than being a structural component of the peritrophic membrane. Among immunity-related transcripts, while lysozymes and lectins were the most highly expressed, several genes belonging to the Toll pathway - found at low levels in the gut of most insects - were identified, contrasting with a low abundance of transcripts from IMD and STAT pathways. Analysis of transcripts related to lipid metabolism indicates that lipids play multiple roles, being a major energy source, a substrate for perimicrovillar membrane formation, and a source for hydrocarbons possibly to produce the wax layer of the hindgut. Transcripts related to amino acid metabolism showed an unanticipated priority for degradation of tyrosine, phenylalanine, and tryptophan. Analysis of transcripts related to signaling pathways suggested a role for MAP kinases, GTPases, and LKBP1/AMP kinases related to control of cell shape and polarity, possibly in connection with regulation of cell survival, response of pathogens and nutrients. Together, our findings present a new view of the triatomine digestive apparatus and will help us understand trypanosome interaction and allow insights into hemipteran metabolic adaptations to a blood-based diet.Journal ArticleResearch Support, N.I.H. IntramuralResearch Support, Non-U.S. Gov'tSCOPUS: ar.jSCOPUS: ar.jinfo:eu-repo/semantics/publishe

    Proteomic Analysis of Cattle Tick Rhipicephalus (Boophilus) microplus Saliva: A Comparison between Partially and Fully Engorged Females

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    Growing knowledge: an overview of Seed Plant diversity in Brazil

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    Abstract An updated inventory of Brazilian seed plants is presented and offers important insights into the country's biodiversity. This work started in 2010, with the publication of the Plants and Fungi Catalogue, and has been updated since by more than 430 specialists working online. Brazil is home to 32,086 native Angiosperms and 23 native Gymnosperms, showing an increase of 3% in its species richness in relation to 2010. The Amazon Rainforest is the richest Brazilian biome for Gymnosperms, while the Atlantic Rainforest is the richest one for Angiosperms. There was a considerable increment in the number of species and endemism rates for biomes, except for the Amazon that showed a decrease of 2.5% of recorded endemics. However, well over half of Brazillian seed plant species (57.4%) is endemic to this territory. The proportion of life-forms varies among different biomes: trees are more expressive in the Amazon and Atlantic Rainforest biomes while herbs predominate in the Pampa, and lianas are more expressive in the Amazon, Atlantic Rainforest, and Pantanal. This compilation serves not only to quantify Brazilian biodiversity, but also to highlight areas where there information is lacking and to provide a framework for the challenge faced in conserving Brazil's unique and diverse flora
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