325 research outputs found
Were sea level changes during the pleistocene in the south atlantic coastal plain a driver of speciation in Petunia (Solanaceae)?
Background: Quaternary climatic changes led to variations in sea level and these variations played a significant role in the generation of marine terrace deposits in the South Atlantic Coastal Plain. The main consequence of the increase in sea level was local extinction or population displacement, such that coastal species would be found around the new coastline. Our main goal was to investigate the effects of sea level changes on the geographical structure and variability of genetic lineages from a Petunia species endemic to the South Atlantic Coastal Plain. We employed a phylogeographic approach based on plastid sequences obtained from individuals collected from the complete geographic distribution of Petunia integrifolia ssp. depauperata and its sister group. We used population genetics tests to evaluate the degree of genetic variation and structure among and within populations, and we used haplotype network analysis and Bayesian phylogenetic methods to estimate divergence times and population growth. Results: We observed three major genetic lineages whose geographical distribution may be related to different transgression/regression events that occurred in this region during the Pleistocene. The divergence time between the monophyletic group P. integrifolia ssp. depauperata and its sister group (P. integrifolia ssp. integrifolia) was compatible with geological estimates of the availability of the coastal plain. Similarly, the origin of each genetic lineage is congruent with geological estimates of habitat availability. Conclusions: Diversification of P. integrifolia ssp. depauperata possibly occurred as a consequence of the marine transgression/regression cycles during the Pleistocene. In periods of high sea level, plants were most likely restricted to a refuge area corresponding to fossil dunes and granitic hills, from which they colonized the coast once the sea level came down. The modern pattern of lineage geographical distribution and population variation was established by a range expansion with serial founder effects conditioned on soil availability
Examining the interrelationship between milk storage and production conditions on milk and dairy products quality
The Irish dairy industry has expanded significantly over the last five years since the abolition of the milk quotas in 2015. The Food Harvest Programme predicted that the milk production would increase by 50% by 2020. The expansion opportunity for Irish dairying has the potential to contribute greatly to the national economy; however, the consistent production of high quality dairy products in accordance with specific international quality parameters is essential to hold market share. The aim of this thesis is to investigate how cold storage conditions at farms can influence the microbiological quality and processability of raw milk, as well as how the quality of raw milk can impact the quality of dairy products. The experimental chapters are divided into two parts; in the first part the studies focused on evaluating the relationship between raw milk cooling conditions on-farm and quality, while in the second part the relationship between raw milk quality, processability and effects on the quality of dairy products were investigated. The thesis was divided into six studies, the specific objectives of each were: (i) to determine the effect of storage temperature and time on the microbiological quality and composition of milk; (ii) to determine the effect of different pre-cooling rates on the microbiological load and composition of milk, as well as on energy requirements; (iii) to monitor the microbiological load of milk throughout the manufacturing process of low-heat skim milk powder, from farm bulk tanks to final product; (iv) to investigate the dynamics of levels of chlorate, perchlorate, trichloromethane, quaternary ammonium compounds and iodine throughout the manufacturing process of skim milk powder; (v and vi) and to determine the effect of different levels of a thermo-resistant protease, produced by a Pseudomonas fluorescens strain, on the cheese-making properties of milk and quality of Cheddar cheese
Tolerância de clones de guaranazeiros a herbicidas.
O objetivo deste trabalho foi o de avaliar a seletividade de herbicidas para clones de guaranazeiro (Paullinia cupana), BRS Amazonas e BRS Maués, em condição de viveiro de mudas no estado do Amazonas
Crop profile method in the identification of transformations in soil attributes by agricultural use
The study was carried in 2002, in Rolandia, north of Parand State, and had as objective to asses the chemistry modifications on a clayey Oxisol, comparing the conventional management system of sugar cane used by growers of Rolandia Cooperative Agriculture, and the systems of no tillage with wheat crop in rotation with others crops, both with eight years of succession, using as reference a native vegetation area localized beside the evaluated systems. Six trenches were digged in each system, for carrying about morphological study by the method of Crop Profile. Based on the identification of the homogeneous morphological units found in the description of the soil profile, samples were taken for chemistry analysis. No tillage system improved the main chemistry and morphological soil characteristics in the 0-0.40 m layer. Sugar cane conventional system exhausts the soil in some profile structures. The Crop Profile Method helped to have an appropriate notion about the main changes found in the studied treatments.29348549
Population genetic structure of Cnesterodon decemmaculatus (Poeciliidae): A freshwater look at the Pampa Biome in southern South America
The Pampas is a Neotropical biome formed primarily by low altitude grasslands and encompasses the southernmost portion of Brazil, Uruguay, and part of Argentina. Despite the high level of endemism, and its significant environmental heterogeneity, Pampean species are underrepresented in phylogeographic studies, especially aquatic organisms. The Pampean hydrological system resulted from a long history of tectonism, climate, and sea level changes since the Neogene. In this study, we examined the population genetic structure of Cnesterodon decemmaculatus, a freshwater fish species that occurs throughout most of the Pampa biome. We characterized mitochondrial and autosomal genetic lineages in populations sampled from Southern Brazil and Uruguay to investigate (1) the correspondence between current drainage systems and evolutionary lineages, (2) the demographic history for each genetic lineage, and (3) the temporal depth of these lineages. Overall, we found that the major evolutionary lineages in this species are strongly related to the main Pampean drainage systems, even though stream capture events may have affected the distribution of genetic lineages among drainages. There was evidence for recent population growth in the lineages occupying drainages closest to the shore, which may indicate the effect of quaternary sea-level changes. In general, divergence time estimates among evolutionary lineages were shallow, ranging from 20,000 to 800,000 years before present, indicating a geologically recent history for this group, as previously reported in other Pampean species. A Bayesian phylogeographical reconstruction suggested that an ancestral lineage probably colonized the Uruguay River Basin, and then expanded throughout the Pampas. This evolutionary scenario may represent useful starting models for other freshwater species having a similar distribution
Avaliação fitossociológica do estrato arbóreo em área de preservação permanente da nascente do córrego Mandacaru, oito anos após plantio de restauração - Maringá, PR
Orientador : Prof. Dr. Christopher Thomas BlumTítulo da capa : Avaliação fitossociológica do estrato arbóreo em área de preservação permanente da nascente do córrego Mandacaru, oito anos após plantio de restauração - Maringá, PRMonografia (especialização) - Universidade Federal do Paraná, Setor de Ciências da Terra, Curso de Especialização em Análise AmbientalInclui referência
Dinâmica de nutrientes e atributos químicos do perfil do solo em função da aplicação de gesso agrícola na cultura de guaranazeiro em formação no Estado do Amazonas.
O objetivo desse trabalho foi avaliar os efeitos do gesso agrícola sobre a distribuição e os teores de nutrientes das camadas do solo, bem como sobre os atributos químicos determinados nas análises de rotina
Projeto de um aplicativo para sintese de funções multi-valores em ambiente Windows
Orientador: Alberto Martins JorgeDissertação (mestrado) - Universidade Estadual de Campinas. Faculdade de Engenharia Eletrica e de ComputaçãoMestrad
Genetic diversity and population structure of naturally rare Calibrachoa species with small distribution in southern Brazil
Calibrachoa is a South-American genus comprising 27 species, several considered endemic or rare; few were subjects in genetic studies. We attempted to generate new data about the phylogenetically related and rare species C. eglandulata, C. sendtneriana, C. serrulata, and C. spathulata concerning their genetic diversity and population structure, which, coupled with their known restricted distribution, could help access their conservation status and contribute to the study of the Brazilian biodiversity. We sequenced 88 individuals for plastid intergenic spacers and genotyped 186 individuals for five microsatellite loci. Compared among each other, C. sendtneriana and C. serrulata presented the highest values of genetic diversity [% (sd) = 0.23 (0.14) and 0.43 (0.25), respectively], followed by C. spathulata [% (sd) = 0.19 (0.12)] and C. eglandulata [% (sd) = 0.02 (0.03)]. Population differentiation was evident for these latter species, whereas it was not significant for C. sendtneriana and C. serrulata. Factors such as habitat specificity and fragmentation, pollination syndrome, and life history could explain the observed patterns. Based on the new genetic data and the species’ biology, a conservation status was assigned for C. sendtneriana and the status of the other three species was reviewed
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