903 resultados para four new taxa
Resumo:
The successful application of metal complexes in the treatment of many diseases, including cancer, is a rapidly expanding area in biomedical chemistry and research. Organotin compounds studies show the versatility and the attractive features of these molecules. In the same manner, has been reported the development of new compounds derivative from bezoylhidrazones, which possess the azomethine fragment (-N = CH-), key pillar for designing new drugs with biological activity. Based on the above, we are interested in to synthesize four tin compounds derivatives from benzoylhidrazones, and the evaluation of their cytotoxic capacity. Conclusions and contribution: In this research work, we reported four new tin compounds derivatives from bezoylhidrazones, which were characterized by spectroscopic and spectrometric techniques and X-ray diffraction In the same manner, cytotoxic ability of each compound was studied and reported and compared with metaled base drugs like cisplatin and carboplatin. Also, in some cases it was possible to use their luminescent ability to study their intracellular behavior.
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Salivary gland polytene chromosomes of 4th instar Anopheles darlingi Root were examined from multiple locations in the Brazilian Amazon. Minor modifications were made to existing polytene photomaps. These included changes to the breakpoint positions of several previously described paracentric inversions and descriptions of four new paracentric inversions, two on the right arm of chromosome 3 and two on the left arm of chromosome 3 that were found in multiple locations. A total of 18 inversions on the X (n = 1) chromosome, chromosome 2 (n = 7) and 3 (n = 11) were scored for 83 individuals from Manaus, Macapá and Porto Velho municipalities. The frequency of 2Ra inversion karyotypes in Manaus shows significant deficiency of heterozygotes (p < 0.0009). No significant linkage disequilibrium was found between inversions on chromosome 2 and 3. We hypothesize that at least two sympatric subpopulations exist within the An. darlingi population at Manaus based on inversion frequencies.
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La présence de disques circumstellaires signale la formation actuelle ou passée de systèmes planétaires, pour lesquels les processus de formation sont encore mal compris. Ce mémoire porte sur la détection et la caractérisation de disques circumstellaires autour d’étoiles de faibles masses (types spectraux > K5) et de naines brunes qui sont candidates ou membres d’associations cinématiques jeunes. Nous présentons ici les résultats de cette recherche ainsi que son implication pour la compréhension des processus de formation et d’évolution des systèmes planétaires. De l’échantillon initial composé de ∼ 1600 objets provenant des relevés BANYAN de Malo et al. ainsi que Gagné et al., dont seulement 600 satisfont nos critères de qualité sur les données, quatre nouveaux candidats de disque ont été découverts en détectant leur excès d’émission infrarouge dans les données d’archive de la mission WISE. Les données du relevé 2MASS ainsi que les spectres synthétiques BT-Settl ont été conjointement utilisés pour modéliser l’émission des étoiles. Les nouveaux candidats, dont les types spectraux sont tardifs (M4.5 à L0) et les masses se situent entre ∼ 13 et 120 M_Jup, ont des températures de disque de ∼ 135–520 K et des luminosités fractionnaires de 0,021–0,15. Pour deux des cibles, nous avons obtenu des spectres dans les longueurs d’onde visibles et infrarouges proches. Ces nouveaux spectres montrent respectivement des signes d’émission en Hα et Paβ, indiquant la présence d’accrétion, et ainsi de gaz, et renforçant l’hypothèse que ces objets sont réellement jeunes. Ces deux objets, vraisemblablement âgés de 40 Ma, pourraient représenter la première détection et caractérisation de disques porteurs de gaz plus vieux que 20 Ma.
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Hydrogen has been considered as a potentially efficient and environmentally friendly alternative energy solution. However, one of the most important scientific and technical challenges that the “hydrogen economy” faces is the development of safe and economically viable on-board hydrogen storage for fuel cell applications, especially to the transportation sector. Ammonia borane (BH3NH3), a solid state hydrogen storage material, possesses exceptionally high hydrogen content (19.6 wt%).However, a fairly high temperature is required to release all the hydrogen atoms, along with the emission of toxic borazine. Recently research interests are focusing on the improvement of H2 discharge from ammonia borane (AB) including lowering the dehydrogenation temperature and enhancing hydrogen release rate using different techniques. Till now the detailed information about the bonding characteristics of AB is not sufficient to understand details about its phases and structures. Elemental substitution of ammonia borane produces metal amidoboranes. Introduction of metal atoms to the ammonia borane structure may alter the bonding characteristics. Lithium amidoborane is synthesized by ball milling of ammonia borane and lithium hydride. High pressure study of molecular crystal provides unique insight into the intermolecular bonding forces and phase stability. During this dissertation, Raman spectroscopic study of lithium amidoborane has been carried out at high pressure in a diamond anvil cell. It has been identified that there is no dihydrogen bond in the lithium amidoborane structure, whereas dihydrogen bond is the characteristic bond of the parent compound ammonia borane. It has also been identified that the B-H bond becomes weaker, whereas B-N and N-H bonds become stronger than those in the parent compound ammonia borane. At high pressure up to 15 GPa, Raman spectroscopic study indicates two phase transformations of lithium amidoborane, whereas synchrotron X-ray diffraction data indicates only one phase transformation of this material. Pressure and temperature has a significant effect on the structural stability of ammonia borane. This dissertation explored the phase transformation behavior of ammonia borane at high pressure and low temperature using in situ Raman spectroscopy. The P-T phase boundary between the tetragonal (I4mm) and orthorhombic (Pmn21) phases of ammonia borane has been determined. The transition has a positive Clapeyron slope which indicates the transition is of exothermic in nature. Influence of nanoconfinemment on the I4mm to Pmn21 phase transition of ammonia borane was also investigated. Mesoporus silica scaffolds SBA-15 with pore size of ~8 nm and MCM-41 with pore size of 2.1-2.7 nm, were used to nanoconfine ammonia borane. During cooling down, the I4mm to Pmn21 phase transition was not observed in MCM-41 nanoconfined ammonia borane, whereas the SBA-15 nanocondfined ammonia borane shows the phase transition at ~195 K. Four new phases of ammonia borane were also identified at high pressure up to 15 GPa and low temperature down to 90 K.
Resumo:
La présence de disques circumstellaires signale la formation actuelle ou passée de systèmes planétaires, pour lesquels les processus de formation sont encore mal compris. Ce mémoire porte sur la détection et la caractérisation de disques circumstellaires autour d’étoiles de faibles masses (types spectraux > K5) et de naines brunes qui sont candidates ou membres d’associations cinématiques jeunes. Nous présentons ici les résultats de cette recherche ainsi que son implication pour la compréhension des processus de formation et d’évolution des systèmes planétaires. De l’échantillon initial composé de ∼ 1600 objets provenant des relevés BANYAN de Malo et al. ainsi que Gagné et al., dont seulement 600 satisfont nos critères de qualité sur les données, quatre nouveaux candidats de disque ont été découverts en détectant leur excès d’émission infrarouge dans les données d’archive de la mission WISE. Les données du relevé 2MASS ainsi que les spectres synthétiques BT-Settl ont été conjointement utilisés pour modéliser l’émission des étoiles. Les nouveaux candidats, dont les types spectraux sont tardifs (M4.5 à L0) et les masses se situent entre ∼ 13 et 120 M_Jup, ont des températures de disque de ∼ 135–520 K et des luminosités fractionnaires de 0,021–0,15. Pour deux des cibles, nous avons obtenu des spectres dans les longueurs d’onde visibles et infrarouges proches. Ces nouveaux spectres montrent respectivement des signes d’émission en Hα et Paβ, indiquant la présence d’accrétion, et ainsi de gaz, et renforçant l’hypothèse que ces objets sont réellement jeunes. Ces deux objets, vraisemblablement âgés de 40 Ma, pourraient représenter la première détection et caractérisation de disques porteurs de gaz plus vieux que 20 Ma.
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The first chapter provides the first evidence on the gross capital flows reactions to the financial sector reform. I establish four new stylized facts. First, the reform is associated with an average increase of 0.03pp in both gross capital flows. Second, immediately after the reform both flows decrease, in the long term they stabilize at a higher than the pre-liberalization levels. Third, the short term dynamics is governed by debt flows, while the long term dynamics are driven by all of the components. Finally, only a complex reform leads to a positive effect. The results are robust to a wide range of robustness checks. In the second chapter we develop a novel theory to explain the recent phenomenon of reshoring, i.e. firms moving back their previously offshored business activities. We firstly provide the evidence for the importance of the quality behind the reshoring decision and then, building on Antoniades (2015) we develop a dynamic heterogeneous firms model with quality choice and offshoring. In the dynamic setting the location decision entails a tradeoff between payroll and quality-related costs. In equilibrium reshoring arises as some firms initially offshore, exploit the increase in profits due to lower wages and finally return to the domestic country in order to further increase the quality. The third chapter provides the new evidence suggesting that selling through global production networks might lead to export upgrade. I relate the sector-level GVCs participation indicators derived from the international Input-Output Tables to the data on the unit values of exports at the product-exporter level. We find a strong association between the export prices and forward participation, in particular for the developing countries. We document also a less robust negative relationship between the GVCs backward participation and unit values of exports.
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Legionella is a Gram-negative bacterium that represent a public health issue, with heavy social and economic impact. Therefore, it is mandatory to provide a proper environmental surveillance and risk assessment plan to perform Legionella control in water distribution systems in hospital and community buildings. The thesis joins several methodologies in a unique workflow applied for the identification of non-pneumophila Legionella species (n-pL), starting from standard methods as culture and gene sequencing (mip and rpoB), and passing through innovative approaches as MALDI-TOF MS technique and whole genome sequencing (WGS). The results obtained, were compared to identify the Legionella isolates, and lead to four presumptive novel Legionella species identification. One of these four new isolates was characterized and recognized at taxonomy level with the name of Legionella bononiensis (the 64th Legionella species). The workflow applied in this thesis, help to increase the knowledge of Legionella environmental species, improving the description of the environment itself and the events that promote the growth of Legionella in their ecological niche. The correct identification and characterization of the isolates permit to prevent their spread in man-made environment and contain the occurrence of cases, clusters, or outbreaks. Therefore, the experimental work undertaken, could support the preventive measures during environmental and clinical surveillance, improving the study of species often underestimated or still unknown.
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During my PhD we focused on different research projects concerning the synthesis and characterization of new rhodium carbonyl clusters. More specifically, we studied the reactivity between Rh4(CO)12 and different bidentate phosphines, obtaining seven different species: Rh4(CO)10(dppe), Rh4(CO)8(dppe)2, Rh4(CO)10(dppf), {Rh4(CO)10(dpp-hexane)}2, {Rh4(CO)10(t-dppe)}2, Rh2(CO)2(dppf)2 and Rh4(CO)9(μ2-dppe)(μ1-dppeO). The reactivity of [Rh7(CO)16]3- with [AuCl4]- and Au(Et2S)Cl led to the formation of seven bimetallic clusters, of which four new ones, namely [Rh16Au6(CO)36]6-, [Rh10Au(CO)26]3-, [Rh16Au6(CO)36]4-, [Rh16Au6(CO)36]5-, [Rh22Au3(CO)47]5-, [Rh19Au5(CO)40]4- and [Rh20Au7(CO)45]5-. The reactivity of [Rh16Au6(CO)36]6- and [Rh10Au(CO)26]3- was studied as well. The reactivity of [Rh7(CO)16]3- with AgBF4, AgNO3 and with Pt(Et2S)2Cl2 was investigated, yielding only to the already known [Rh6N(CO)15]-, [PtRh5(CO)15]- and [PtRh4(CO)14]2- compounds. [Rh7(CO)16]3- war reacted with SnCl2·2H2O in acetone obtaining [Rh7Sn4Cl10(CO)14]5-, and [Rh12Sn(CO)23Cl2]4- was reacted with H+ obtaining [Rh18Sn3Cl2(CO)44]4-. Reactivity of [Rh7(CO)16]3- with InCl3 resulted in the isolation of [Rh12In(CO)28]3- and [Rh11In3(CO)25Cl2]3-, already known in our research lab, and the new [HRh11In(CO)26]3-. Moreover, a more straightforward synthesis for [Rh6InCl3(CO)15]2- was found, and this also led to the isolation of the [Rh6InCl2(DMF)(CO)15]-. The recover or rhodium as valuable carbonyl compound was also studied, and starting from a mixture of by-products it was possible to obtain the starting material [Rh7(CO)16]3-.
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The taxonomic identity in microbial eukaryotes remains an impediment to discussing ecology, biogeography and phylogeny, mainly due to a lack of standards in organism descriptions and few comparative works. The lobose testate amoebae (Arcellinida) present an ideal study system, as progress is severely hindered due to taxonomic confusion. In the present survey, we have examined the morphology, biometry and ecology of 2400 individuals in the genus Arcella Ehrenberg, 1832, collected from the Tiete River in Sao Paulo, Brazil. We then contrasted these new data with 26 previously described species, varieties and forms, looking for consistencies and trying to establish distinct entities. Using a combination of morphology and multivariate statistics we were able to determine 4 distinct taxa (Arcella hemisphaerica, Arcella discoides, Arcella gibbosa and Arcella brasiliensis), each of them encompassing a number of other non-distinct nominal taxa. We describe in detail each of the 4 taxa with notes on ecology and biogeography, and list the indistinguishable names in an effort to make identification and taxonomy in the testate amoebae a more objective and precise exercise by clarifying the taxonomic identity.
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Gasteruptiinae is the largest Gasteruptiidae subfamily, with circa 400 species that have been grouped into the worldwide Gasteruption Latreille. Based on a cladistic analysis with 43 morphological characters, 40 ingroup taxa representing all biogeographic regions, and seven outgroups (four Hyptiogastrinae, two Aulacidae and one Evaniidae), I confirm the monophyly of Gasteruptiinae and Gasteruption and recognize three exclusively Neotropical small genera: Plutofoenus Kieffer (revalidated) (southern South America), Spinolafoenus Macedo n. gen. (Chile) and Trilobitofoenus Macedo n. gen. (Central and South America). Gasteruption, supported by four synapomorphies, remains the most speciose genus in the subfamily. The four Gasteruptiinae genera are keyed and described. Seven species are keyed and described or redescribed: Plutofoenus chaeturus (Schletterer) n. comb., P. edwardsi Turner, P. paraguayensis (Schrottky), Spinolafoenus ruficornis (Spinola) n. comb., Trilobitofoenus alvarengai Macedo n. sp., T. plaumanni Macedo n. sp. and T. sericeus (Cameron) n. comb. (lectotype designated).
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Eighteen Pteridophyte taxa in 15 genera are reported as new for the Territory of Amapá, Brazil. The collections area a result of a recent Projeto Flora Amazônica/Programa Flora expedition to that region, and update previous lists of taxa for Amapá.In 1975, Tryon and Conant publised a checklist of the ferns of the Brazilian Amazônia reporting 84 taxa for the Territory of Amapá. The paucity of records for Amapá reflects, at least in part, the amount of botanical exploration. The most complete list of taxa occurring in the Territory is an unpublished list of collection compiled by J. M. Pires. This compilation reports 118 taxas for the Territory of Amapá. The following list is intended to update both the Pires compilation an the Tryon and Conant checklist for the Territor. These records are the result of a Projeto Flora Amazônica/Programa Flora expedition to the region in the latter part of 1979. Species were included in this list is not reportes in the compilation of colections for Amapá, or listed as specifically occurrin in Amapá in the monographs and revisions consulted for listed as specifically occurring in Amapá in the monograohs and revisions consulted for identification (Evans, 1969; Kramer, 1957, 1978; de la Sota, 1960; Lellinger, 1972; Maxon & Morton, 1938; Scamman, 1960, Smith, 1971; Tryon, 1941, 1964).This list reports 18 taxa in 15 genera, increasing the number of taxa in Amapá from the 118 listed by Pires to 136. Most of the taxa reported here might have been predicted to occur in Amapá on the basis of their distribution records for surrounding regions.Each species is followed by a collection number. The collection number is that of D. F. Austin, C. E. Nauman, R. S. Secco, C. Rosario, and M. R. Santos except for four collections in which R. S. Secco was absent and B. V. Rabelo was present, and these are indicated after the collection number. Specimens are deposited in the herbaria of the Museu Paraense Emílio Goeldi, Belém, Brazil and the United States. The family system is essentially that used by Tyron and Conant.
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This paper presents a search for Higgs bosons decaying to four leptons, either electrons or muons, via one or two light exotic gauge bosons Zd, H→ZZd→4ℓ or H→ZdZd→4ℓ. The search was performed using pp collision data corresponding to an integrated luminosity of about 20 fb−1 at the center-of-mass energy of s√=8TeV recorded with the ATLAS detector at the Large Hadron Collider. The observed data are well described by the Standard Model prediction. Upper bounds on the branching ratio of H→ZZd→4ℓ and on the kinetic mixing parameter between the Zd and the Standard Model hypercharge gauge boson are set in the range (1--9)×10−5 and (4--17)×10−2 respectively, at 95% confidence level assuming the Standard Model branching ratio of H→ZZ∗→4ℓ, for Zd masses between 15 and 55 GeV. Upper bounds on the effective mass mixing parameter between the Z and the Zd are also set using the branching ratio limits in the H→ZZd→4ℓ search, and are in the range (1.5--8.7)×10−4 for 15
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n.s. no.37(1997)