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Universidade Estadual de Londrina

EducationLondrina, Brazil
About: Universidade Estadual de Londrina is a education organization based out in Londrina, Brazil. It is known for research contribution in the topics: Population & Toxoplasma gondii. The organization has 13052 authors who have published 19291 publications receiving 212123 citations.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the superoxide radical anion O2− from tetra(4-carboxyphenyl)porphyrin (TCPP) adsorbed on TiO2 in DMSO and irradiated by visible light was studied using EPR spectroscopy.
Abstract: The generation of superoxide radical anion O2− from tetra(4-carboxyphenyl)porphyrin (TCPP) adsorbed on TiO2 in DMSO and irradiated by visible light was studied using EPR spectroscopy and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as spin trap. A chemical filter was used to remove light with wave lengths <500 nm. A multiline EPR spectrum was observed, characteristic of a mixture of two adducts, the first corresponding to DMPO–O2− and the second to the so-called nitroxide-like radical. Hyperfine coupling constants determined for the DMPO–O2− adduct are: aN = 14.1 G, aHβ = 10.8 G and aHγ = 1.4 G, and for the nitroxide-like radical adduct aN = 14 G. An increased intensity of the EPR lines corresponding to the nitroxide-like radical adduct was observed under irradiation without chemical filter, which suggests a possible DMPO–O2− decomposition. No singlet oxygen could be detected by EPR spectroscopy using 2,2,6,6-tetramethyl-4-piperidone (TEMP) as spin trap and by chemical trapping using anthracene as the trap.

102 citations

Journal ArticleDOI
TL;DR: Radiodensity was similar within enamel groups, but bovine dentin presented higher radiodensity than human one regardless of age groups, and enamel was always more radiodense than dentin and also presented higher KHN (p=0.001).

102 citations

Journal ArticleDOI
TL;DR: The Double Chooz experiment as mentioned in this paper measured the mixing angle θ13 with the new total neutron capture detection technique from the full data set, yielding sin2(2θ13)
Abstract: Neutrinos were assumed to be massless particles until the discovery of the neutrino oscillation process. This phenomenon indicates that the neutrinos have non-zero masses and the mass eigenstates (ν1, ν2, ν3) are mixtures of their flavour eigenstates (νe, νμ, ντ). The oscillations between different flavour eigenstates are described by three mixing angles (θ12, θ23, θ13), two differences of the squared neutrino masses of the ν2/ν1 and ν3/ν1 pairs and a charge conjugation parity symmetry violating phase δCP. The Double Chooz experiment, located near the Chooz Electricite de France reactors, measures the oscillation parameter θ13 using reactor neutrinos. Here, the Double Chooz collaboration reports the measurement of the mixing angle θ13 with the new total neutron capture detection technique from the full data set, yielding sin2(2θ13) = 0.105 ± 0.014. This measurement exploits the multidetector configuration, the isoflux baseline and data recorded when the reactors were switched off. In addition to the neutrino mixing angle measurement, Double Chooz provides a precise measurement of the reactor neutrino flux, given by the mean cross-section per fission 〈σf〉 = (5.71 ± 0.06) × 10−43 cm2 per fission, and reports an empirical model of the distortion in the reactor neutrino spectrum.

102 citations

Journal ArticleDOI
TL;DR: A large hydraulic diversity is found, covering as much as 44% of the global angiosperm variation in P50, suggesting the evolution of a stress-tolerance syndrome to nutrients and drought and has important implications for modelling and predicting forest and species resilience to climate change.
Abstract: Species distribution is strongly driven by local and global gradients in water availability but the underlying mechanisms are not clear. Vulnerability to xylem embolism (P50 ) is a key trait that indicates how species cope with drought and might explain plant distribution patterns across environmental gradients. Here we address its role on species sorting along a hydro-topographical gradient in a central Amazonian rainforest and examine its variance at the community scale. We measured P50 for 28 tree species, soil properties and estimated the hydrological niche of each species using an indicator of distance to the water table (HAND). We found a large hydraulic diversity, covering as much as 44% of the global angiosperm variation in P50 . We show that P50 : contributes to species segregation across a hydro-topographic gradient in the Amazon, and thus to species coexistence; is the result of repeated evolutionary adaptation within closely related taxa; is associated with species tolerance to P-poor soils, suggesting the evolution of a stress-tolerance syndrome to nutrients and drought; and is higher for trees in the valleys than uplands. The large observed hydraulic diversity and its association with topography has important implications for modelling and predicting forest and species resilience to climate change.

102 citations

Journal ArticleDOI
TL;DR: In the state of SÃO PAO, Brazil, there is a legal instrument (SMA 08-2008) whose aim is to increase the effectiveness of tropical forest restoration projects in particular as discussed by the authors.
Abstract: Around the world, there is growing desire and momentum for ecological restoration to happen faster, with better quality, and in more extensive areas. The question we ask is how can laws and governmental regulations best contribute to effective, successful, and broad-scale restoration? In the state of S˜ ao Paulo, Brazil, there is a legal instrument (SMA 08-2008) whose aim is to increase the effectiveness of tropical forest restoration projects in particular. It establishes, among other things, requirements regarding the minimum number of native tree species to be reached within a given period of time in restoration projects and the precise proportion of functional groups or threatened species to be included when reforestation with native species is used as a restoration technique. There are, however, two differing perspectives among Brazilian restoration ecologists on the appropriateness of such detailed legal rules. For some, the rules help increase the chances that mandatory projects of ecological restoration will succeed. For the other group, there is no single way to achieve effective ecosystem restoration, and the existing science and know-how are far from sufficient to establish standardized technical and methodological norms or to justify that such norms be imposed. Both points of view are discussed here, aiming to help those developing new legislation and improving existing laws about ecological restoration. The precedents established in S˜ ao Paulo, and at the federal level in Brazil, and the ongoing debate about those laws are worth considering and possibly applying elsewhere.

102 citations


Authors

Showing all 13138 results

NameH-indexPapersCitations
Michael Maes11580752050
Fernando Q. Cunha8868231501
Mariangela Hungria6738915219
Petar Popovski5975621009
Waldiceu A. Verri5424910311
Thiago M. Cunha542689519
Emerson Franchini524029620
Celso Vataru Nakamura5141810908
Diego Augusto Santos Silva5138953077
Susan M. Tarlo5026310850
Paulo Caramelli453669666
Fabio Pitta4421311925
Joaquim Gama-Rodrigues432258380
Ricardo Almeida432507304
Hamilton Roschel432355894
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202324
2022151
20211,220
20201,433
20191,333
20181,308