Coupling between ion-acoustic waves and neutrino oscillations

The work investigates the coupling between ion-acoustic waves and neutrino flavor oscillations in a nonrelativistic electron-ion plasma under the influence of a mixed neutrino beam. Neutrino oscillations are mediated by the flavor polarization vector dynamics in a material medium. The linear dispersion relation around homogeneous static equilibria is developed. When resonant with the ion-acoustic mode, the neutrino flavor oscillations can transfer energy to the plasma exciting a new fast unstable mode in extreme astrophysical scenarios. The growth rate and the unstable wavelengths are determined in typical type II supernova parameters. The predictions can be useful for a new indirect probe on neutrino oscillations in nature

Taking Root: Enduring Effect of Rhizosphere Bacterial Colonization in Mangroves

Mangrove forests are of global ecological and economic importance, but are also one of the world's most threatened ecosystems. Here we present a case study examining the influence of the rhizosphere on the structural composition and diversity of mangrove bacterial communities and the implications for mangrove reforestation approaches using nursery-raised plants.A barcoded pyrosequencing approach was used to assess bacterial diversity in the rhizosphere of plants in a nursery setting, nursery-raised transplants and native (non-transplanted) plants in the same mangrove habitat. In addition to this, we also assessed bacterial composition in the bulk sediment in order to ascertain if the roots of mangrove plants affect sediment bacterial composition. We found that mangrove roots appear to influence bacterial abundance and composition in the rhizosphere. Due to the sheer abundance of roots in mangrove habitat, such an effect can have an important impact on the maintenance of bacterial guilds involved in nutrient cycling and other key ecosystem functions. Surprisingly, we also noted a marked impact of initial nursery conditions on the rhizosphere bacterial composition of replanted mangrove trees. This result is intriguing because mangroves are periodically inundated with seawater and represent a highly dynamic environment compared to the more controlled nursery environment.In as far as microbial diversity and composition influences plant growth and health, this study indicates that nursery conditions and early microbial colonization patterns of the replants are key factors that should be considered during reforestation projects. In addition to this, our results provide information on the role of the mangrove rhizosphere as a habitat for bacteria from estuarine sediments

Seascape genomics and phylogeography of the sailfish (Istiophorus platypterus)

Permeable phylogeographic barriers characterize the vast open ocean, boosting gene flow and counteracting population differentiation and speciation of widely distributed and migratory species. However, many widely distributed species consists of distinct populations throughout their distribution, evidencing that our understanding of how the marine environment triggers population and species divergence are insufficient. The sailfish is a circumtropical and highly migratory billfish that inhabits warm and productive areas. Despite its ecological and socioeconomic importance as a predator and fishery resource, the species is threatened by overfishing, requiring innovative approaches to improve their management and conservation status. Thus, we presented a novel high-quality reference genome for the species and applied a seascape genomics approach to understand how marine environmental features may promote local adaptation and how it affects gene flow between populations. We delimit two populations between the Atlantic and Indo-Western Pacific oceans and detect outlier loci correlated with sea surface temperature, salinity, oxygen, and chlorophyll concentrations. However, the most significant explanatory factor that explains the differences between populations was isolation by distance. Despite recent population drops, the sailfish populations are not inbred. For billfishes in general, genome-wide heterozygosity was found to be relatively low compared to other marine fishes, evidencing the need to counteract overfishing effects. In addition, in a climate change scenario, management agencies must implement state-of-the-art sequencing methods, consider our findings in their management plans, and monitor genome-wide heterozygosity over time to improve sustainable fisheries and the long-term viability of its populations.LA/P/0101/2020info:eu-repo/semantics/publishedVersio

Diabetic retinopathy and ocular melanoma: how far we are?

Diabetic retinopathy causes vascular damage to retinal neurons, presenting characteristics of chronic inflammation. The development of new therapies capable of combating vision loss involves knowledge of inflammatory retinal changes. Studies in animal models and patients with diabetes have shown a high expression of the inflammatory molecules that are involved in the progression of diabetic retinopathy. Uveal melanoma is an eye tumour that remains highly deadly, because despite the correct treatment, it still causes metastasis in about 50% of patients. This type of tumour has the ability to produce and store melanin, which may result in resistance to therapy. Over time there has been development of new therapies for this disease, such as radiotherapy and surgical resection. In this review, we discuss diabetic retinopathy and ocular melanoma, their relationship with angiogenesis and the current anti-angiogenic therapies for their treatment.The authors acknowledge the financial support received from the Portuguese Science and Technology Foundation (FCT/MCT) and from European Funds (PRODER/COMPETE) under the project references M-ERANET/0004/2015-PAIRED, UIDB/04469/2020 (strategic fund) and UID/AGR/04033/2019 (CITAB), co-financed by FEDER, under the Partnership Agreement PT2020. The authors also acknowledge the support of the research project: Nutraceutica come supporto nutrizionale nel paziente oncologico, CUP: B83D18000140007.info:eu-repo/semantics/publishedVersio

Genetic diversity in two threatened species of guitarfish (Elasmobranchii: Rhinobatidae) from the Brazilian and Argentinian coasts: an alert for conservation

The guitarfishes Pseudobatos horkelii and Pseudobatos percellens meet the criteria for threatened status as Critically Endangered (CR) and Endangered (EN), respectively. Both species occur in the Southern Atlantic Ocean. Considering the lack of data on the genetic structure of these species, the present study evaluated the genetic variability and population structure of the P. horkelii and P. percellens in the southern region of Brazil and the northern coast of Argentina, based on sequences of mitochondrial DNA, Control Region (D-loop). Samples of P. horkelii (n = 135) were analyzed in six localities situated in Northern Argentina, along the Brazilian states’ coast. The mean of nucleotide diversity was 0.0053, the ΦST was 0.4277 and demographic analysis of P. horkelii suggests the existence of stability of the populations, with D = 0.9929, FS = 2.0155, SSD = 0.0817, R = 0.2153. In P. percellens (n = 101) were analyzed from six Brazilian localities along the coast of Santa Catarina, Paraná, and São Paulo. The mean nucleotide diversity was 0.0014 and ΦST value of 0.2921, the demographic analysis indicates a high migration rate of P. percellens among the localities evaluated, with D = 0.5222, FS = 0.3528, SSD = 0.01785, R = 0.3890.As raias violas Pseudobatos horkelii e Pseudobatos percellens, são listados como “Criticamente em Perigo” (CR) e “Em Perigo” (EN), respectivamente. Ambas as espécies ocorrem no Sul do Oceano Atlântico. Considerando a falta de dados sobre a estrutura genética dessas espécies, o presente estudo avaliou a variabilidade genética e a estrutura populacional de P. horkelii e P. percellens na região sudeste do Brasil e litoral norte da Argentina, com base em sequências de DNA mitocondrial, região de controle (D-loop). Amostras de 135 indivíduos de P. horkelii analisados em seis localidades, situadas no norte da Argentina e ao longo da costa dos estados brasileiros. A média da diversidade nucleotídica foi de 0.0053, o índice ΦST foi de 0.4277 e a análise demográfica de P. horkelii, indicou a existência de estabilidade das populações, com D = 0.9929, Fus = 2.0155, SSD = 0.0817, R = 0.2153. Em 101 exemplares de P. percellens, foram analisados em seis localidades brasileiras ao longo do litoral de Santa Catarina, Paraná e São Paulo. A diversidade nucleotídica média foi de 0.0014 e o valor ΦST de 0.2921, a análise demográfica indicou uma alta taxa de migração de P. percellens entre as localidades analisadas, com D = 0.5222, FS = 0.3528, SSD = 0.01785, R = 0.3890.Fil: Cruz, Vanessa P.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Adachi, Aisni M. C. L.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Oliveira, Pablo H.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Ribeiro, Giovana S.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Paim, Fabilene G.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Souza, Bruno C.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Rodrigues, Alexandre S. F.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Vianna, Marcelo. Universidade Federal do Rio de Janeiro; BrasilFil: Delpiani, Sergio Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Díaz de Astarloa, Juan Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Rotundo, Matheus M.. Universidade Santa Cecília; BrasilFil: Mendonça, Fernando F.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Oliveira, Claudio. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Lessa, Rosangela P.. Universidad Federal Rural Pernambuco; BrasilFil: Foresti, Fausto. Universidade Estadual Paulista Julio de Mesquita Filho; Brasi

Ensino de Geociências na universidade

In colonial times, in Brazil, although intense mining activities occurred in the search for gold and diamonds, relevant geoscientific actions did not occur. In the 19th century, a few geological exploratory trips were made, from which several written contributions resulted. Moreover, important institutions were created, such as the National Observatory, the Meteorological Service, the Magnetic Observatory at Vassouras and the Mining School of Ouro Preto in 1876, The formal teaching of Geosciences in Brazil started only in 1957, with the ”Campaign for the training of geologists” (CAGE), that created and provided material and human resources to four Geology undergraduate courses. In Meteorology the first course was in 1973, in Oceanography in 1971 and in Geophysics in 1983. Now, 48 Brazilian universities offer 71 undergraduate courses in Geosciences, 33 in Geology, 3 in Geological Engineering, 14 in Meteorology, 13 in Oceanography and 8 in Geophysics. Fifty-seven graduate programs exist in Brazil, 13 of which are considered of excellence, indicating that the area is mature and consolidated. Most geologists and geophysicists were absorbed in geological mapping activities, as well as mining and oil exploration. Meteorologists dedicated themselves to meteorological and climatic monitoring, as well as to projects in hydroelectric, wind and solar energy. Graduates in Oceanography worked in institutions related to the environment, agriculture, and to the Ministry of the Navy. The atmospheric and oceanographic sciences are of global relevance in studies of climatic changes and global warming. In turn, the major challenge of geologists and geophysicists is to improve knowledge of the Brazilian territory, at the local and regional scale.No Brasil colonial, apesar de intensa atividade mineira na busca de ouro e diamantes, não houve práticas geocientíficas relevantes. No século XIX ocorreram diversas explorações geológicas, das quais resultou uma vasta contribuição escrita. Além disso foram criadas importantes instituições, como o Observatório Nacional, o Serviço Meteorológico, o Observatório Magnético de Vassouras e a Escola de Minas de Ouro Preto em 1876. O ensino formal de Geociências no Brasil foi iniciado apenas em 1957, com a Campanha de Formação de Geólogos (CAGE), que criou e forneceu recursos materiais e humanos para quatro cursos de graduação em Geologia. Na Meteorologia a graduação se iniciou em 1963, na Oceanografia em 1971, e na Geofísica em 1983. Atualmente, 47 universidades brasileiras oferecem 71 cursos de graduação nas Geociências. Há 33 cursos de Geologia, três de Engenharia Geológica, 14 de Meteorologia, 13 de Oceanografia e 8 de Geofísica. Há no Brasil 57 programas de pós-graduação em Geociências, 13 dos quais considerados de excelência, indicando que a situação atual da área é de consolidação e maturidade. Geólogos e geofísicos foram absorvidos, em sua maioria, pelas atividades de mapeamento geológico, exploração mineral e de petróleo. Meteorologistas dedicaram-se ao monitoramento meteorológico e climático, e também a projetos de energia hidroelétrica, eólica e solar. Na Oceanografia, os formados atuaram em órgãos relacionados com ambiente, agricultura e no Ministério da Marinha. Quanto à pesquisa, as ciências atmosféricas e oceanográficas são de grande relevância global, no estudo das mudanças climáticas e o aquecimento global. Por sua vez, o maior desafio de geólogos e geofísicos é o de melhorar do conhecimento do território brasileiro, na escala local ou regional

High connectivity of the Crocodile Shark between the Atlantic and Southwest Indian Oceans: highlights for conservation

Among the various shark species that are captured as bycatch in commercial fishing operations, the group of pelagic sharks is still one of the least studied and known. Within those, the crocodile shark, Pseudocarcharias kamoharai, a small-sized lamnid shark, is occasionally caught by longline vessels in certain regions of the tropical oceans worldwide. However, the population dynamics of this species, as well as the impact of fishing mortality on its stocks, are still unknown, with the crocodile shark currently one of the least studied of all pelagic sharks. Given this, the present study aimed to assess the population structure of P. kamoharai in several regions of the Atlantic and Indian Oceans using genetic molecular markers. The nucleotide composition of the mitochondrial DNA control region of 255 individuals was analyzed, and 31 haplotypes were found, with an estimated diversity Hd = 0.627, and a nucleotide diversity pi = 0.00167. An analysis of molecular variance (AMOVA) revealed a fixation index phi(ST) = -0.01118, representing an absence of population structure among the sampled regions of the Atlantic Ocean, and between the Atlantic and Indian Oceans. These results show a high degree of gene flow between the studied areas, with a single genetic stock and reduced population variability. In panmictic populations, conservation efforts can be concentrated in more restricted areas, being these representative of the total biodiversity of the species. When necessary, this strategy could be applied to the genetic maintenance of P. kamoharai.Foundation for Research Support of the Sao Paulo State - FAPESP [2011/23787-0, 2010/51903-2]; Portuguese Foundation for Science and Technology (FCT) [SFRH/BPD/93936/2013]; Foundation for Research Support of the Sao Paulo State - FAPESP [2011/23787-0, 2010/51903-2]; Portuguese Foundation for Science and Technology (FCT) [SFRH/BPD/93936/2013]info:eu-repo/semantics/publishedVersio

U_e(1)xU_g(1) Actions in 2+1-Dimensions: Full Vectorial Electric and Magnetic Fields

It is considered a dimensional reduction of Ue(1)xUg(1) 3+1-dimensional electromagnetism with a gauge field (photon) and a pseudo-vector gauge field (pseudo-photon) to 2+1-dimensions. In the absence of boundary effects, the quantum structure is maintained, while when boundary effects are considered, as have been previously studied, a cross Chern-Simons term between both gauge fields is present, which accounts for topological effects and changes the quantum structure of the theory. Our construction maintains the dimensional reduced action invariant under parity (P) and time-inversion (T). We show that the theory has two massive degrees of freedom, corresponding to the longitudinal modes of the photon and of the pseudo-photon and briefly discuss the quantization procedures of the theory in the topological limit (wave functional quantization) and perturbative limit (an effective dynamical current theory), pointing out directions to solve the constraints and deal with the negative energy contributions from pseudo-photons. We recall that the physical interpretation of the fields in the planar system is new and is only meaningful in the context of Ue(1)xUg(1) electromagnetism. In this work it is shown that all the six electromagnetic vectorial fields components are present in the dimensional reduced theory and that, independently of the embedding of the planar system, can be described in terms of the two gauge fields only. As far as the author is aware it is the first time that such a construction is fully justified, thus allowing a full vectorial treatment at variational level of electromagnetism in planar systems.Comment: 8 pages, 1 figur