Utilização do espaço e do tempo por Cingulados (Mammalia, Xenarthra) da savana uruguaia e da Mata Atlântica Meridional

As espécies da ordem Cingulata Illiger, 1811, coloquialmente chamadas de tatus, são encontradas exclusivamente no continente americano. Presentes em diversas regiões florestais e campestres, elas apresentam uma variedade de padrões ecológicos espaço-temporais, inclusive em relação às formas como respondem a diferentes ambientes e a distúrbios provocados por humanos e animais exóticos. Infelizmente, existe uma escassez de conhecimentos sobre a ecologia dos tatus na maior parte de sua distribuição, o que dificulta a formulação de esforços de conservação. Usando registros de vídeos obtidos por armadilhas fotográficas, este estudo providencia uma avaliação de fatores que influenciam na ocupação de sítios e atividade diária da fauna de tatus da Savana Uruguaia e da Mata Atlântica meridional, incluindo covariáveis relacionadas ao ambiente físico e a atividades humanas e de animais exóticos. Devido a um número limitado de registros da maioria das espécies, esta dissertação enfatiza os padrões de ocupação e atividade da espécie registrada mais frequentemente, o tatu galinha (Dasypus novemcinctus Linnaeus, 1758). Entretanto, também fornece informações sobre os padrões demonstrados pelas espécies menos detectadas. Modelos de ocupação de sítios, utilizados para testar a influência de covariáveis ambientais, revelaram uma correlação positiva entre a probabilidade de ocupação de sítios do tatu-galinha e as covariáveis distância de assentamentos humanos e detecção de cães domésticos (Canis lupus familiaris Linnaeus, 1758). Visto que a Savana Uruguaia e a Mata Atlântica meridional possuem variações ambientais internas consideráveis, foram realizadas análises independentes para cada região. Nesta escala, nenhuma covariável influenciou a ocupação do tatu-galinha. Testes de uniformidade de Rayleigh revelaram que o tatu-galinha, tatu-peba (Euphractus sexcinctus Linnaeus, 1758), tatu-mulita (Dasypus septemcinctus hybridus Desmarest, 1804) e tatu-de rabo-mole-grande (Cabassous tatouay Desmarest, 1804) apresentaram padrões de atividade diária não-uniformes e majoritariamente noturnos. Não foram obtidos registros do tatu-mirim (Dasypus septemcinctus septemcinctus Linnaeus, 1758). Embora baseados em poucos registros, os resultados sobre o tatu-peba e o tatu-mulita são surpreendentes, pois diferem do conhecimento sobre a atividade destas espécies, majoritariamente diurnas em outras partes de suas distribuições. O tatu-galinha também apresentou alta sobreposição temporal com as outras três espécies de tatus e baixa sobreposição temporal com cães domésticos e javalis (Sus scrofa Linnaeus, 1758) e atividade similar entre a Savana Uruguaia e a Mata Atlântica meridional e entre sítios com e sem detecção das espécies exóticas. A relação positiva com a distância de assentamentos humanos sugere que as populações de tatu-galinha na Mata Atlântica meridional podem estar sofrendo, em relação às da Savana Uruguaia, devido à uma maior densidade humana. Já a relação positiva com a detecção de cães pode indicar que ambas as espécies utilizam os mesmos locais, mas não ao mesmo tempo, como pudemos observar em nossos resultados de sobreposição de atividade diária. Por fim, visto que o tatu-peba e o tatu-mirim são considerados comuns e existem em alta densidade em outras partes de suas distribuições, os poucos registros obtidos geram preocupações sobre os estados de conservação locais destas espécies. No geral, este estudo apresenta novos conhecimentos sobre os padrões de ocupação e de atividade de diversas espécies de tatu em regiões pouco estudadas e muito degradadas nos limites de suas distribuições geográficas. Estes achados podem servir para direcionar futuras pesquisas em busca da manutenção das funções ecológicas e serviços ecossistêmicos prestados por estas espécies.The species of the order Cingulata Illiger, 1811, colloquially referred to as armadillos, are found exclusively in the American continent. Present in a wide range of forests and grasslands, they show a variety of spatio-temporal ecological patterns, including the ways in which they respond to different environments and to disturbances provoked by humans or exotic animals. Unfortunately, there is a dearth of knowledge regarding the ecology of armadillos in most of their distribution, which complicates the creation of conservation efforts. Using video records obtained through camera traps, this study provides an assessment of drivers which influence the site occupancy and daily activity patterns of the armadillo fauna in the Uruguayan Savanna and southern Atlantic Forest, including site-specific covariates related to the physical environment and to the activities of humans and exotic animals. Due to a limited number of records of most species, this dissertation emphasizes occupancy and activity patterns of the species, which was most frequently recorded, the nine-banded armadillo (Dasypus novemcinctus Linnaeus, 1758). However, it also provides information about the patterns presented by species with fewer detections. Site occupancy models, used to test the influence of environmental covariates, revealed a positive correlation between the site occupancy probability of the nine-banded armadillo and the distance to human settlements and detection of domestic dogs (Canis lupus familiaris Linnaeus, 1758) covariates. As the Uruguayan Savanna and southern Atlantic Forest show considerable internal environmental variabilities, independent analyses were made for each region. On this scale, no covariate influenced the occupancy of the nine-banded armadillo. Rayleigh uniformity tests revealed that the nine banded, six-banded (Euphractus sexcinctus Linnaeus, 1758), southern long-nosed (Dasypus septemcinctus hybridus Desmarest, 1804) and greater naked-tailed (Cabassous tatouay Desmarest, 1804) armadillos showed non-uniform and mostly nocturnal daily activity patterns. No records were obtained for the seven-banded armadillo (Dasypus septemcinctus septemcinctus Linnaeus, 1758). Although based on few records, the results for the six-banded and southern long-nosed armadillos are surprising, as they differ from knowledge of these species’ activities, which are mostly diurnal elsewhere in their distributions. The nine-banded armadillo presented low temporal overlap with domestic dogs and wild boars (Sus scrofa Linnaeus, 1758), and similar activity patterns between the Uruguayan Savanna and southern Atlantic Forest and between sites where the exotic species were detected and those where they were not. The positive relation with distance to human settlements suggests that nine-banded armadillo populations in the southern Atlantic Forest might be suffering, relative to those of the Uruguayan Savanna, due to a higher human density. The positive relation with dog detection might indicate that both species use the same locations, but at different times, as we could observe in our temporal overlap results. Finally, as the six-banded and seven-banded armadillos are considered common and exist in high densities in other portions of their distributions, the low number of records obtained raise concerns over these species’ local conservation statuses. Overall, this study presents novel knowledge about the occupancy and activity patterns of several species of armadillo in poorly studied and very degraded regions in the limits of their geographic distributions. These findings could serve to direct future research aiming to maintain the ecological functions and ecosystem services provided by these species

Time resolved emission spectroscopy of poly(2,5-dicyano-p-phenylene-vinylene) films

Films of poly (2,5-dicyano-p-phenylene vinylene), DCNPPV, were obtained by electrochemical synthesis over gold thin layer (20 nm) transparent electrode deposited on a glass plate. The DCNPPV films of 4 µm thickness were produced by electropolymerization process of α,α,α',α'-tetrabromo-2-5-dicyano-p-xilene at different applied potentials (-0.15, -0.25, -0.40, -0.60, -0.80, and -1.0 V) using 0.1 mol L-1 of tetraethylammonium bromide in acetonitrile as the supporting electrolyte. The emission decays have three exponential components: a fast component in the picosecond range (200-400 ps), and two other of about one and five nanoseconds at 293 K. The fluorescence quenching process seems to occur by exciton trapping in a low-energy site and quenching by residual bromine monomer attached at the end of the polymer chain. However, the electrochemical synthesis generates entrapped bromide or ion pairs during the growth step of the film which also contributes to the deactivation. The change of the electrolyte from bromide to perchlorate reduces significantly this additional quenching effect by allowing ion exchange of formed bromide with the nonquenching perchloride anion.Filmes finos de poli(2,5-diciano-p-fenileno vinileno), DCNPPV, foram produzidos por síntese eletroquímica com variação do potencial aplicado de-0,15 até-1,0 V, e depositados sobre camada fina de ouro sobre vidro. A cinética de estado excitado destes materiais foi investigada por medidas de decaimentos de fluorescência. Os filmes apresentam decaimentos com três componentes, uma rápida da ordem de 200-400 picossegundos, e outra duas componentes de aproximadamente um e cinco nanossegundos, na temperatura de 293 K. O decaimento de fluorescência ocorre pela desativação em sítios de baixa energia na cadeia polimérica conjugada e por supressão do estado excitado por monômeros bromados terminais da cadeia e íons brometo aprisionados durante o crescimento eletroquímico do filme. A mudança do ânion do eletrólito suporte de brometo para perclorato reduziu de modo significativo essa contribuição de supressão do estado excitado como resultado da troca iônica por uma espécie não supressora.FAPESPCNP

12,500+ and counting: biodiversity of the Brazilian Pampa

Knowledge on biodiversity is fundamental for conservation strategies. The Brazilian Pampa region, located in subtropical southern Brazil, is neglected in terms of conservation, and knowledge of its biodiversity is fragmented. We aim to answer the question: how many, and which, species occur in the Brazilian Pampa? In a collaborative effort, we built species lists for plants, animals, bacteria, and fungi that occur in the Brazilian Pampa. We included information on distribution patterns, main habitat types, and conservation status. Our study resulted in referenced lists totaling 12,503 species (12,854 taxa, when considering infraspecific taxonomic categories [or units]). Vascular plants amount to 3,642 species (including 165 Pteridophytes), while algae have 2,046 species (2,378 taxa) and bryophytes 316 species (318 taxa). Fungi (incl. lichenized fungi) contains 1,141 species (1,144 taxa). Animals total 5,358 species (5,372 taxa). Among the latter, vertebrates comprise 1,136 species, while invertebrates are represented by 4,222 species. Our data indicate that, according to current knowledge, the Pampa holds approximately 9% of the Brazilian biodiversity in an area of little more than 2% of Brazil’s total land The proportion of species restricted to the Brazilian Pampa is low (with few groups as exceptions), as it is part of a larger grassland ecoregion and in a transitional climatic setting. Our study yielded considerably higher species numbers than previously known for many species groups; for some, it provides the first published compilation. Further efforts are needed to increase knowledge in the Pampa and other regions of Brazil. Considering the strategic importance of biodiversity and its conservation, appropriate government policies are needed to fund studies on biodiversity, create accessible and constantly updated biodiversity databases, and consider biodiversity in school curricula and other outreach activitie

Time resolved fluorescence anisotropy of basic dyes bound to poly(methacrylic acid) in solution

Solutions of atactic poly(methacrylic acid), PMAA, with molecular weights in the range of (1.6 to 3.4) x 10(5) g mol-1, and labeled with the fluorescent dyes 9-aminoacridine or Nile blue were studied by photophysical measurements as a function of solvent viscosity and polarity. The conformational behavior of the PMAA chain segments around the fluorescent probe was reported by the change in the rotational diffusion of the dyes. Ethylene glycol swells the polymer chain compared with the more contracted conformation of PMAA in 50% water/ethylene glycol. The change in the rotational relaxation time of the dye bound to PMAA with the decrease of water content in the solvent mixture indicates a progressive expansion of polymer chain to a more open coil form in solution

Transferência de energia entre corantes catiônicos em sistemas homogêneos

In this work, the energy transfer by dipole-dipole interaction between cationic dyes in n-alcohols (methanol, ethanol, 1-propanol and 1-butanol) is studied by time resolved and steady state fluorescence measurements. The critical radii of energy transfer were determined by three independent methods; the spectral overlap, fluorescence decay profiles, and relative intensity measurements. In all solvents, R0 values of the dye pairs obtained from spectral overlap were between 40 to 90 Å. Steady state and time resolved fluorescence measurements resulted in values of R0 in the range of 50 - 80 Å, with good correlation of values

Monitoring the Activity of Immobilized Lipase with Quinizarin Diester Fluoro-Chromogenic Probe

Quinizarin diester is used as a fluoro-chromogenic substrate of the activity of lipase supported in poly(methylmetacrylate) beads (CALB, Novozym® 435) dispersed in organic solvents. The monoester and diester of quinizarin are both non-fluorescent species contrasting with the enzymatic product quinizarin that shows optical absorption in the visible region and strong fluorescence signal. The enzymatic conversion is accomplished by spectroscopic measurements and it follows a sigmoid curve from which the mean reaction time of the enzymatic process can be determined. This parameter indicates the enzyme activity of the immobilized lipase. Its dependency with the amount of lipase allowed the determination of the ratio of the catalytic rate and the Michaelis constant (kc/Km) and the experimental value found was (1.0 ± 0.1) × 10−2 mg−1/min in the case of quinizarin diacetate