Soy protein–gum karaya conjugate: emulsifying activity and rheological behavior in aqueous system and oil in water emulsion

The main objective of this study is to investigate the effects of mixing and conjugation of soy protein isolate (SPI) with gum karaya on the characteristics of the hybrid polymer (protein–gum) in both aqueous systems and oil-in-water (O/W) emulsions. It was hypothesized that the covalent linkage of gum karaya with SPI would improve the emulsifying activity and rheological properties of both polymers. Conjugation occurred under controlled conditions (i.e., 60 °C and 75 % relative humidity, 3 days). The conjugated hybrid polymer produced smaller droplet with better uniformity, higher viscosity and stronger emulsifying activity than native gum karaya, suggesting the conjugated polymer provided a bulkier secondary layer with more efficient coverage around oil droplets, thereby inducing stronger resistance against droplet aggregation and flocculation. Emulsions containing the native gum karaya produced the largest droplet size among all prepared emulsions (D 3,2 = 8.6 μm; D 4,3 = 22.4 μm); while the emulsion containing protein–gum conjugate (1:1 g/g) had the smallest droplet size (D 3,2 = 0.2 μm; D 4,3 = 0.7 μm) with lower polydispersity. The protein–gum conjugate (1:1 g/g) also showed the highest elastic and viscous modulus, the lowest polydispersity (span) and the highest emulsifying activity among all native, mixed and conjugated polymers. Therefore, the percentage of gum karaya used for production of O/W emulsion can be decreased by partially replacing it with the conjugated gum

Nearly tight bounds for testing function isomorphism

We study the problem of testing isomorphism (equivalence up to relabelling of the variables) of two Boolean functions f, g: {0, 1} n → {0, 1}. Our main focus is on the most studied case, where one of the functions is given (explicitly) and the other function may be queried. We prove that for every k ≤ n, the worst-case query complexity of testing isomorphism to a given k-junta is Ω(k) and O(k log k). Consequently, the query complexity of testing function isomorphism is e Θ(n). Prior to this work, only lower bounds of Ω(log k) queries were known, for limited ranges of k, proved by Fischer et al. (FOCS 2002), Blais and O’Donnell (CCC 2010), and recently by Alon and Blais (RANDOM 2010). The nearly tight O(k log k) upper bound improves on the e O(k 4) upper bound from Fischer et al. (FOCS 2002). Extending the lower bound proof, we also show polynomial query-complexity lower bounds for the problems of testing whether a function can be computed by a circuit of size ≤ s, and testing whether the Fourier degree of a function is ≤ d. This answers questions posed by Diakonikolas et al. (FOCS 2007). We also address two closely related problems – 1. Testing isomorphism to a k-junta with one-sided error: we prove that for any 1 < k < n − 1, the query complexity is Ω(log ` ´ n), which is almost optimal. Thi

Climate change impacts on freshwater fishes: a Patagonian perspective

The fish fauna of Patagonian lakes comprises a small, unique group of native species and several exotic ones. The consequences of environmental changes for Patagonian fish populations vary according to the physiology of the species considered. Several previously predicted facts such as extirpations, extinctions, and translocations have occurred and human actions such as transport, introduction, and stocking of exotic species suggest a more complex future. We discuss the historical biogeography of Patagonian freshwater ichthyofauna to help us better understand their present adaptations and physiological ecology. We also address potential interactions between climate change and processes such as migration, species introductions, and invasions. There is still much to learn from Patagonian fishes to comprehend how these species will endure environmental changes.Fil: Becker, Leandro Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales. Universidad Nacional del Comahue. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales.; ArgentinaFil: Crichigno, Sonia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales. Universidad Nacional del Comahue. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales.; ArgentinaFil: Cussac, Victor Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales. Universidad Nacional del Comahue. Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales.; Argentin

Mesozoic dinosaurs from Brazil and their biogeographic implications

The record of dinosaur body-fossils in the Brazilian Mesozoic is restricted to the Triassic of Rio Grande do Sul and Cretaceous of various parts of the country. This includes 21 named species, two of which were regarded as nomina dubia, and 19 consensually assigned to Dinosauria. Additional eight supraspecific taxa have been identified based on fragmentary specimens and numerous dinosaur footprints known in Brazil. In fact, most Brazilian specimens related to dinosaurs are composed of isolated teeth and vertebrae. Despite the increase of fieldwork during the last decade, there are still no dinosaur body-fossils of Jurassic age and the evidence of ornithischians in Brazil is very limited. Dinosaur faunas from this country are generally correlated with those from other parts of Gondwana throughout the Mesozoic. During the Late Triassic, there is a close correspondence to Argentina and other south-Pangaea areas. Mid-Cretaceous faunas of northeastern Brazil resemble those of coeval deposits of North Africa and Argentina. Southern hemisphere spinosaurids are restricted to Africa and Brazil, whereas abelisaurids are still unknown in the Early Cretaceous of the latter. Late Cretaceous dinosaur assemblages of south-central Brazil are endemic only to genus or, more conspicuously, to species level, sharing closely related taxa with Argentina, Madagascar, Indo-Pakistan and, to a lesser degree, continental Africa.<br>O registro osteológico de dinossauros no Mesozóico brasileiro está restrito a rochas triássicas do Rio Grande do Sul e estratos cretáceos de várias partes do país. Isto inclui 21 espécies nominais, sendo duas referidas como nomina dubia, e 19 consensualmente classificadas como dinossauros. Oito táxons supraespecíficos adicionais baseados em material fragmentado e diversas pegadas são conhecidos no Brasil. De fato, a maior parte dos espécimes é composta de dentes isolados e vértebras. Apesar do aumento em trabalhos de campo na última década, não há exemplar esqueletal de dinossauro no Jurássico brasileiro, e é escassa a evidência de Ornithischia. Faunas dinossaurianas aqui registradas são em geral correlatas com aquelas da Pangéia durante o Mesozóico. No Triássico Superior, há uma correspondência próxima com a Argentina e outras regiões sul-gondwânicas. Faunas do Cretáceo médio do nordeste brasileiro são semelhantes às dos depósitos coevos do norte da África e Argentina. Registros de espinossaurídeos no hemisfério sul estão restritos à África e Brasil, enquanto abelissaurídeos não são conhecidos no Cretáceo Inferior deste último. Assembleias de dinossauros da região sul e central do Brasil são endêmicas apenas em nível de gênero e, mais conspicuamente, espécie, compartilhando táxons proximamente relacionados com assembleias da Argentina, Indo-Paquistão, e, num menor grau, África continental