Search

Your search keyword '"Freitas L"' showing total 1,320 results
Start Over Author "Freitas L"
1,320 results on '"Freitas L"'

301. Seascape genetics of a globally distributed, highly mobile marine mammal: the short-beaked common dolphin (genus Delphinus).

Author

Kolokotronis, S-O, Amaral, AR, Beheregaray, LB, Bilgmann, K, Boutov, D, Freitas, L, Robertson, KM, Sequeira, M, Stockin, KA, Coelho, MM, Möller, LM, Kolokotronis, S-O, Amaral, AR, Beheregaray, LB, Bilgmann, K, Boutov, D, Freitas, L, Robertson, KM, Sequeira, M, Stockin, KA, Coelho, MM, and Möller, LM

Abstract

Identifying which factors shape the distribution of intraspecific genetic diversity is central in evolutionary and conservation biology. In the marine realm, the absence of obvious barriers to dispersal can make this task more difficult. Nevertheless, recent studies have provided valuable insights into which factors may be shaping genetic structure in the world's oceans. These studies were, however, generally conducted on marine organisms with larval dispersal. Here, using a seascape genetics approach, we show that marine productivity and sea surface temperature are correlated with genetic structure in a highly mobile, widely distributed marine mammal species, the short-beaked common dolphin. Isolation by distance also appears to influence population divergence over larger geographical scales (i.e. across different ocean basins). We suggest that the relationship between environmental variables and population structure may be caused by prey behaviour, which is believed to determine common dolphins' movement patterns and preferred associations with certain oceanographic conditions. Our study highlights the role of oceanography in shaping genetic structure of a highly mobile and widely distributed top marine predator. Thus, seascape genetic studies can potentially track the biological effects of ongoing climate-change at oceanographic interfaces and also inform marine reserve design in relation to the distribution and genetic connectivity of charismatic and ecologically important megafauna.

Published
2012

302. Testing Flavor Changing Neutrino Interactions in Long Baseline Experiments

Author

Gago, A. M., Freitas, L. P., Peres, O. L. G., and Funchal, R. Zukanovich

Subjects
High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Physics::Instrumentation and Detectors, High Energy Physics::Lattice, High Energy Physics::Phenomenology, FOS: Physical sciences, High Energy Physics::Experiment
Abstract

We have investigated the possibility of discerning mass from flavor changing neutrino interactions induced $\nu_\mu \to \nu_\tau$ oscillations in the long baseline neutrino experiments K2K and MINOS. We have found that for virtually any value of the flavor conserving parameter $\epsilon^\prime$ it will be possible to, independently, distinguish these two mechanisms at K2K, if the flavor changing parameter $\epsilon$ is in the range $\epsilon \gsim 0.77$, and at MINOS, if $\epsilon \gsim 0.2$. Moreover, if K2K measures a depletion of the expected $\nu_\mu$ flux then MINOS will either observe or discard completely flavor changing neutrino oscillations., Comment: 21 pages with 7 figures, uses Elsart style and epsfig

Published
1999
Full Text
View/download PDF

303. Evaluation of a single-stage current source inverter with high-voltage gain supplied by a polymer electrolyte membrane fuel cell.

Author

Garcia, L. S., de Freitas, L. C., Buiatti, G. M., Coelho, E. A. A., Farias, V. J., and Freitas, L. C. G.

Abstract

Alternative energy sources have for some time attracted great interest in the area of static converter development. This fact is related in greater part to issues such as sustainability and detrimental effects on the natural environment, which all contribute to the viability of this type of energy source. The principal challenge therefore becomes the development of systems that transform the produced DC current into AC current. The authors of this study have therefore focused their efforts upon the establishment of a new control strategy applied to a step-down/step-up single-stage inverter with imposed waveforms of input current and output voltage. The proposed control strategy provides high-voltage gain without the use of a high-frequency transformer, which contributes to weight and size reduction in the proposed DC-AC converter structure. A theoretical analysis is presented and corroborated through the experimental results of a 400 W laboratory prototype fed by a polymer electrolyte membrane fuel cell. [ABSTRACT FROM AUTHOR]

Published
2012
Full Text
View/download PDF

304. Novel true zero current turn-on and turn-off converter family: analysis and experimental results.

Author

Dias, E. C., Freitas, L. C. G., Coelho, E. A. A., Vieira, J. B., and de Freitas, L. C.

Abstract

A novel soft-commutation cell capable of providing zero current switching (ZCS) operation keeping the main switch current equal to the load current is presented. Substituting the typical pulse width modulation cell found in classic power converter structures by the presented ZCS cell and taking to account the invariance principle, a new ZCS converter family could be achieved and it is also presented here. The operation and main properties of this cell are also included. A theoretical approach for the design of the proposed cell applied to a DC–DC buck converter is presented and corroborated by the experimental results with an 800 W laboratory prototype. [ABSTRACT FROM AUTHOR]

Published
2010
Full Text
View/download PDF

305. In vivophotothermal tumour ablation using gold nanorods

Author

de Freitas, L F, primary, Zanelatto, L C, additional, Mantovani, M S, additional, Silva, P B G, additional, Ceccini, R, additional, Grecco, C, additional, Moriyama, L T, additional, Kurachi, C, additional, Martins, V C A, additional, and Plepis, A M G, additional

Published
2013
Full Text
View/download PDF

307. DESESTABILIZAÇÃO DE UMA SUSPENSÃO COLOIDAL DE DIÓXIDO DE TITÂNIO.

Author

FREITAS, L. D. C., BALTAR, C. A. M., and FRANÇA, S. C. A.

Abstract

The sedimentation rate can be increased by the processes of aggregation (coagulation, agglomeration, or flocculation). The direct flocculation of colloidal particles is not sufficient for the destabilization of a colloidal suspension. Due to the very small size of the colloids, the flocs can remain with very slow sedimentation rate. Therefore, a previous step of aggregation is necessary for an efficient flocculation. In this study it was compared the influence of pre-aggregation, with a surfactant - dodecylamine (DDA) and a multivalent salt - hexahydrated aluminum chloride (HAC) in the flocculation of colloidal particles of titanium dioxide with a hydrolyzed polyacrylamide (PAMH). The results were evaluated in terms of turbidity of the supernatant and final compaction of the sediment. The pre-aggregation significantly improves the flocculation with PAMH. The pre-treatment with DDA produces largest flocs, low turbidity overflow, and more compacted sediment, compared to the pre-treatment with HAC. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

308. Bottlenose dolphin Tursiops truncatus group dynamics, site fidelity, residency and movement patterns in the Madeira Archipelago (North-East Atlantic).

Author

Dinis, A, Alves, F, Nicolau, C, Ribeiro, C, Kaufmann, M, Cañadas, A, and Freitas, L

Subjects
BOTTLENOSE dolphin, HOME range (Animal geography), CETACEA, POPULATION ecology
Abstract

The bottlenose dolphinTursiops truncatusis one of the most frequently sighted cetacean species in the Madeira Archipelago (North-East Atlantic); however, little is known about its population ecology in these waters. Photo-identification undertaken during systematic, non-systematic and opportunistic surveys conducted between 2001 and 2012 was used to assess group dynamics, site fidelity, residency and movement patterns of bottlenose dolphins in the archipelago. Three different patterns of residency were assigned, based on individual sighting histories. Group size ranged between 2 and 90 individuals (median 12), with no significant monthly difference in group size. All resident dolphins formed a core, complex network with migrant and transient dolphins. In contrast, satellite clusters were formed exclusively by transient individuals. The lagged identification rate (LIR) model indicated that a dolphin remained in the area for an average of 90 days, whereas the average time an individual spent outside the study area was approximately 313 days. The Madeira Archipelago appears to be only a section of a much larger home range for this population, with the dolphins exhibiting three different patterns of occurrence that associate with each other. The information gained about this poorly studied population contributes to the overall knowledge of bottlenose dolphins in insular oceanic habitats. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

309. Endoparasites of wild animals from three biomes in the State of Mato Grosso, Brazil.

Author

Ramos, D. G. S., Santos, A. R. G. L. O., Freitas, L. C., Correa, S. H. R., Kempe, G. V., Morgado, T. O., Aguiar, D. M., Wolf, R. W., Rossi, R. V., Sinkoc, A. L., and Pacheco, R. C.

Subjects
ANIMAL populations, BIOMES, VETERINARY hospitals
Abstract

Copyright of Arquivo Brasileiro de Medicina Veterinaria e Zootecnia is the property of Universidade Federal de Minas Gerais, Escola de Veterinaria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2016
Full Text
View/download PDF

310. Microparticles Containing Curcumin Solid Dispersion: Stability, Bioavailability and Anti-Inflammatory Activity.

Author

Teixeira, C. C. C., Mendonça, L. M., Bergamaschi, M. M., Queiroz, R. H. C., Souza, G. E. P., Antunes, L. M. G., and Freitas, L. A. P.

Abstract

This work aimed at improving the solubility of curcumin by the preparation of spray-dried ternary solid dispersions containing Gelucire®50/13-Aerosil® and quantifying the resulting in vivo oral bioavailability and anti-inflammatory activity. The solid dispersion containing 40% of curcumin was characterised by calorimetry, infrared spectroscopy and X-ray powder diffraction. The solubility and dissolution rate of curcumin in aqueous HCl or phosphate buffer improved up to 3600- and 7.3-fold, respectively. Accelerated stability test demonstrated that the solid dispersion was stable for 9 months. The pharmacokinetic study showed a 5.5-fold increase in curcumin in rat blood plasma when compared to unprocessed curcumin. The solid dispersion also provided enhanced anti-inflammatory activity in rat paw oedema. Finally, the solid dispersion proposed here is a promising way to enhance curcumin bioavailability at an industrial pharmaceutical perspective, since its preparation applies the spray drying, which is an easy to scale up technique. The findings herein stimulate further in vivo evaluations and clinical tests as a cancer and Alzheimer chemoprevention agent. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

311. Bees, birds and yellow flowers: pollinator-dependent convergent evolution of UV patterns.

Author

Papiorek, S., Junker, R. R., Alves‐dos‐Santos, I., Melo, G. A. R., Amaral‐Neto, L. P., Sazima, M., Wolowski, M., Freitas, L., Lunau, K., and Dafni, A.

Subjects
FLOWERS, COLOR of plants, CONVERGENT evolution, POLLINATION by bees, EFFECT of ultraviolet radiation on plants, PLANT diversity, POLLINATION by birds, ANGIOSPERMS
Abstract

Colour is one of the most obvious advertisements of flowers, and occurs in a huge diversity among the angiosperms. Flower colour is responsible for attraction from a distance, whereas contrasting colour patterns within flowers aid orientation of flower visitors after approaching the flowers. Due to the striking differences in colour vision systems and neural processing across animal taxa, flower colours evoke specific behavioural responses by different flower visitors. We tested whether and how yellow flowers differ in their spectral reflectance depending on the main pollinator. We focused on bees and birds and examined whether the presence or absence of the widespread UV reflectance pattern of yellow flowers predicts the main pollinator. Most bee-pollinated flowers displayed a pattern with UV-absorbing centres and UV-reflecting peripheries, whereas the majority of bird-pollinated flowers are entirely UVabsorbing. In choice experiments we found that bees did not show consistent preferences for any colour or pattern types. However, all tested bee species made their first antennal contact preferably at the UV-absorbing area of the artificial flower, irrespective of its spatial position within the flower. The appearance of UV patterns within flowers is the main difference in spectral reflectance between yellow bee- and bird-pollinated flowers, and affects the foraging behaviour of flower visitors. The results support the hypothesis that flower colours and the visual capabilities of their efficient pollinators are adapted to each other. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

312. Stranding and by-catch of cetaceans in the Northeastern Atlantic during 1996

Author

Pérez, C. (Concepción), López, A. (Alfredo), Sequeira, M. (Marina), Silva, M. (Mónica), Herrera, R. (Rogelio), Gonçalves, J.M. (João M.), Valdés, P. (Pablo), Mons, J.L. (José Luis), Freitas, L. (Luis), Lens, S. (Santiago), and Cendrero-Uceda, O. (Orestes)

Abstract

In this study we have analysed the stranding and by-catch records of cetaceans during 1996. The area of investigation is located in the Northeastern Atlantic. The results of data provide information concerning the seasonal and spatial distribution and relative frequency of the catches in the different areas. A total of 549 specimens was reported. Of these, 84% were found stranded and only the 16% resulted from by-catches from fishing boats or being stranded with injury by the nets. The common dolphin is the species most frequently involved in nets (72.4%). Young common dolphins were mainly caught and shows a similar frequency of females and males. Other cetaceans caught include Tursiops tnmcatus (5 .7%), while the others like Stenella coeruleoalba, Stenella frontalis, Grampus griseus, Kogia breviceps and Phocoena phocoena have only been caught sporadically. The location ofby-catches in the different sectors reflect human fishing activities.

Published
1997

314. CZT Support for Z Extensions

Author

Romijn, J, Smith, G, VanDePol, J, Miller, T, Freitas, L, Malik, P, Utting, M, Romijn, J, Smith, G, VanDePol, J, Miller, T, Freitas, L, Malik, P, and Utting, M

Abstract

Community Z Tools (CZT) is an integrated framework for the Z formal specification language. In this paper, we show how it is also designed to support extensions of Z, in a way that minimises the work required to build a new Z extension. The goals of the framework are to maximise extensibility and reuse, and minimise code duplication and maintenance effort. To achieve these goals, CZT uses a variety of different reuse mechanisms, including generation of Java code from a hierarchy of XML schemas, XML templates for shared code, and several design patterns for maximising reuse of Java code. The CZT framework is being used to implement several integrated formal methods, which add object-orientation, real-time features and process algebra extensions to Z. The effort required to implement such extensions of Z has been dramatically reduced by using the CZT framework.

Published
2005

326. The Static Gravitational Field of a Spherically Symmetric Body

Author

Novello, M., Freitas, L. R., and De Lorenci, V. A.

Subjects
General Relativity and Quantum Cosmology, FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc)
Abstract

We continue here the exam \cite{LuMa} of a theory of gravity that satisfies the Einstein Equivalence Principle (EEP) for any kind of matter/energy, except for the gravitational energy. This is part of a research program that intends to re-examine the standard Feynman-Deser approach of field theoretical derivation of Einstein\rq s General Relativity. The hypothesis implicit in such precedent derivations \cite{Feynman} \cite{Deser} concerns the universality of gravity interaction. Although there is a strong observational basis supporting the universality of matter to gravity interaction, there is not an equivalent situation that supports the hypothesis that gravity interacts with gravity as any other form of non-gravitational energy. We analyse here a kind of gravity-gravity interaction distinct from GR but, as we shall see, that conforms with the actual status of observation. We exhibit the gravitational field produced by a spherically symmetric static configuration as described in this field theory of gravity. The values that we obtain for the standard PPN parameters ($\alpha = \beta = \gamma = 1$) coincide with those of General Relativity. Thus, as we pointed out in a previous paper, the main different aspect of our theory and GR concerns the velocity of the gravitational waves. Since there is a large expectation that the detection of gravitational waves will occur in the near future, the question of which theory describes Nature better will probably be settled soon., Comment: 15 pagex, LateX

Published
1995

338. Vascular access

Author

Santos, C., primary, Ventura, A., additional, Gomes, A. M., additional, Pereira, S., additional, Almeida, C., additional, Seabra, J., additional, Segelmark, M., additional, Mattsson, L., additional, Said, S., additional, Olde, B., additional, Solem, K., additional, Yu, X., additional, Zhang, B., additional, Sun, B., additional, Mao, H., additional, Xing, C., additional, Gruss, E., additional, Portoles, J., additional, Tato, A., additional, Lopez-Sanchez, P., additional, Jimenez, P., additional, de la Cruz, R., additional, Furaz, K., additional, Martinez, S., additional, Mas, M., additional, Andres, M. M., additional, Corchete, E., additional, Kim, Y. O., additional, Kim, H. G., additional, Kim, B. S., additional, Song, H. C., additional, Choi, E. J., additional, Ibeas, J., additional, Vallespin, J., additional, Fortuno, J. R., additional, Rodriguez-Jornet, A., additional, Grau, C., additional, Merino, J., additional, Branera, J., additional, Perendreu, J., additional, Granados, I., additional, Mateos, A., additional, Jimeno, V., additional, Moya, C., additional, Ramirez, J., additional, Falco, J., additional, Gimenez, A., additional, Garcia, M., additional, Morgado, E., additional, Pinho, A., additional, Guedes, A., additional, Guerreiro, R., additional, Mendes, P., additional, Bexiga, I., additional, Silva, A., additional, Marques, J., additional, Neves, P., additional, Shibata, K., additional, Iwamoto, T., additional, Murakami, T., additional, Ono, S., additional, Kaneda, T., additional, Kuji, T., additional, Kawata, S., additional, Satta, H., additional, Tamura, K., additional, Toya, Y., additional, Yanagi, M., additional, Umemura, S., additional, Yasuda, G., additional, Yong, O. L., additional, Lim, W. W. L., additional, Yong, K. M., additional, Tay, K. H., additional, Lim, E. K., additional, Yang, W. S., additional, Tan, S. G., additional, Choong, H. L., additional, Hill, A., additional, Blatter, D., additional, Kim, S. Y., additional, Min, J.-K., additional, Park, W. D., additional, Rodriguez- Jornet, A., additional, Marcet, M., additional, Vinuesa, X., additional, Mateo, A., additional, Fernandez, M., additional, Rivera, J., additional, Shibahara, H., additional, Shibahara, N., additional, Takahashi, S., additional, Kanaa, M., additional, Wright, M. J., additional, Sandoe, J. A. T., additional, Freudiger, H., additional, Dupret, J., additional, Jacquemoud, M.-C., additional, Rossi, L., additional, Kampouris, C., additional, Hatzimpaloglou, A., additional, Karamouzis, M., additional, Pliakos, C., additional, Malindretos, P., additional, Roudenko, I., additional, Grekas, D., additional, Costa, A. C., additional, Santana, A., additional, Neves, F., additional, Costa, A. G. d., additional, Chaudhry, M., additional, Bhola, C., additional, Joarder, M., additional, Lok, C., additional, Coentrao, L., additional, Faria, B., additional, Frazao, J., additional, Pestana, M., additional, Sun, X.-f., additional, Yang, Y., additional, Wang, J., additional, Lin, H.-l., additional, Li, J.-j., additional, Yao, L., additional, Zhao, J.-Y., additional, Zhang, Z.-m., additional, Lun, L.-d., additional, Zhang, J.-r., additional, Zhang, Y.-m., additional, Li, M.-x., additional, Jiang, S.-m., additional, Wang, Y., additional, Zhu, H.-y., additional, Chen, X.-m., additional, Caeiro, F., additional, Carvalho, D., additional, Cruz, J., additional, Ribeiro dos Santos, J., additional, Nolasco, F., additional, Bartlett, R., additional, Pandya, B., additional, Viana, N., additional, Machado, S., additional, Gil, C., additional, Lucas, C., additional, Mendes, A., additional, Barata, J., additional, Freitas, L., additional, Campos, M., additional, Rikker, C., additional, Juhasz, E., additional, Toth, A., additional, Vizi, I., additional, Tornoci, L., additional, Rosivall, L., additional, Tovarosi, S., additional, Cho, S., additional, Kim, S., additional, Lee, Y.-j., additional, Kanai, H., additional, Harada, K., additional, Nasu, S., additional, Shinozaki, M., additional, Esenturk, M., additional, Zengin, M., additional, Ogun, F., additional, Akdemir, A., additional, Colak, C., additional, Pekince, G., additional, Gerasimovska, V., additional, Oncevski, A., additional, Gerasimovska-Kitanovska, B., additional, Sikole, A., additional, Kiselev, N., additional, Chernyshev, S., additional, Zlokazov, V., additional, Idov, E., additional, Bacallao Mendez, R., additional, Avila, A., additional, Salgado, J., additional, Llerena, B., additional, Badell, A., additional, Aties, M., additional, Severn, A., additional, Metcalfe, W., additional, Traynor, J., additional, Boyd, J., additional, Kerssens, J., additional, Henderson, A., additional, Simpson, K., additional, Roca-Tey, R., additional, Samon, S., additional, Ibrik, O., additional, Roda, E., additional, Gonzalez, J. C., additional, Viladoms, J., additional, Bamidis, P., additional, Liaskos, C., additional, Papagiannis, A., additional, Vrochides, D., additional, Frantzidis, C., additional, Sarafidis, P., additional, Lasaridis, A., additional, Chryssogonidis, I., additional, Nikolaidis, P., additional, Perndreu, J., additional, Moyses Neto, M., additional, Ferreira, V., additional, Martinez, R., additional, Tercariol, C. A. S., additional, Lima, D. A. F. S., additional, Figueiredo, J. F. C., additional, Costa, J. A. C., additional, Alayoud, A., additional, Hamzi, A., additional, Akhmouch, I., additional, Aatif, T., additional, Oualim, Z., additional, Jankovic, A., additional, Ilic, M., additional, Damjanovic, T., additional, Djuric, Z., additional, Popovic, J., additional, Adam, J., additional, and Dimkovic, N., additional

Published
2011
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results