Adubacao nitrogenada do girassol, no periodo chuvoso e na safrinha na regiao do cerrado.

2001

Manejo da fertilidade do solo na implantacao da cultura da mangueira.

2001

Manejo da fertilidade do solo e adubacao no pre-plantio e plantio da gravioleira.

2001

Manejo da irrigação e da fertirrigação com uréia na produtividade e qualidade do maracujá-doce.

2008

Estudo da suscetibilidade aos antibióticos em isolados de Enterobacteriaceae provenientes de suiniculturas Portuguesas

Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Ciências Farmacêuticas

Epidemiology and comparative analysis of Yersinia in Ireland

Yersiniosis is an acute or chronic enteric zoonosis caused by enteropathogenic Yersinia species. Although yersiniosis is predominantly associated with gastroenteric forms of infection, extraintestinal forms are often reported from the elderly or patients with predisposing factors. Yersiniosis is often reported in countries with cold and mild climates (Northern and Central Europe, New Zealand and North of Russian Federation). The Irish Health Protection Surveillance Centre (HPSC) currently records only 3-7 notified cases of yersiniosis per year. At the same time pathogenic Yersinia enterocolitica is recovered from pigs (main source of pathogenic Y. enterocolitica) at the levels similar to that observed in Yersinia endemic countries. Introduction of Yersinia selective culture procedures may increase Yersinia isolation rates. To establish whether the small number of notifications of human disease was an underestimate due to lack of specific selective culture for Yersinia we carried out a prospective culture study of faecal samples from outpatients with diarrhoea, with additional culture of appendix and throat swabs. Higher levels of anti-Yersinia seroprevalence than yersiniosis notification rates in endemic countries suggests that most yersiniosis cases are unrecognised by culture. Subsequently, in addition to a prospective culture study of clinical specimens, we carried out serological screening of Irish blood donors and environmental screening of human sewage. Pathogenic Yersinia strains were not isolated from 1,189 faeces samples, nor from 297 throat swabs, or 23 appendix swabs. This suggested that current low notification rates in Ireland are not due to the lack of specific Yersinia culture procedures. Molecular screening detected a wider variety of Y. enterocolitica-specific targets in pig slurry than in human sewage. A serological survey for antibodies against Yersinia YOP (Yersinia Outer Proteins) proteins in Irish blood donors found antibodies in 25%, with an age-related trend to increased seropositivity, compatible with the hypothesis that yersiniosis may have been more prevalent in Ireland in the recent past. Y. enterocolitica is a heterogeneous group of microorganisms that comprises strains with different degree of pathogenicity. Although non-pathogenic Y. enterocolitica lack conventional virulence factors, these strains can be isolated from patients with diarrhoea. Insecticidal Toxin Complex (ITC) and Cytolethal Distending Toxins can potentially contribute to the virulence of non-pathogenic Y. enterocolitica in the absence of other virulence factors. We compared distribution of ITC and CDT loci among pathogenic and non-pathogenic Y. enterocolitica. Additionally, to demonstrate potential pathogenicity of non-pathogenic Y. enterocolitica we compared their virulence towards Galleria mellonella larvae (a non-mammalian model of human bacterial infections) with the virulence of highly and mildly pathogenic Y. enterocolitica strains. Surprisingly, virulence of pathogenic and non-pathogenic Y. enterocolitica in Galleria mellonella larvae observed at 37°C did not correlate with their pathogenic potential towards humans. Comparative phylogenomic analysis detects predicted coding sequences (CDSs) that define host-pathogen interactions and hence providing insights into molecular evolution of bacterial virulence. Comparative phylogenomic analysis of microarray data generated in Y. enterocolitica strains isolated in the Great Britain from humans with diarrhoea and domestic animals revealed high genetic heterogeneity of these species. Because of the extensive human, animal and food exchanges between the UK and Ireland the objective of this study was to gain further insight into genetic heterogeneity and relationships among clinical and non-clinical Y. enterocolitica strains of various pathogenic potential isolated in Ireland and Great Britain. No evidence of direct transfer of strains between the two countries was found.

Phosphorus export from a restored wetland ecosystem in response to natural and experimental hydrologic fluctuations

Wetland restoration is a commonly used approach to reduce nutrient loading to freshwater and coastal ecosystems, with many wetland restoration efforts occurring in former agricultural fields. Restored wetlands are expected to be effective at retaining or removing both nitrogen and phosphorus (P), yet restoring wetland hydrology to former agricultural fields can lead to the release of legacy fertilizer P. Here, we examined P cycling and export following rewetting of the Timberlake Restoration Project, a 440 ha restored riverine wetland complex in the coastal plain of North Carolina. We also compared P cycling within the restored wetland to two minimally disturbed nearby wetlands and an adjacent active agricultural field. In the restored wetland we observed increased soluble reactive phosphorus (SRP) concentrations following initial flooding, consistent with our expectations that P bound to iron would be released under reducing conditions. SRP concentrations in spring were 2.5 times higher leaving the restored wetland than a forested wetland and an agricultural field. During two large-scale drawdown and rewetting experiments we decreased the water depth by 1 m in ∼10 ha of inundated wetland for 2 weeks, followed by reflooding. Rewetting following experimental drainage had no effect on SRP concentrations in winter, but SRP concentrations did increase when the experiment was repeated during summer. Our best estimates suggest that this restored wetland could release legacy fertilizer P for up to a decade following hydrologic restoration. The time lag between restoration and biogeochemical recovery should be incorporated into management strategies of restored wetlands. Copyright 2010 by the American Geophysical Union.

Estimation of in-canopy ammonia sources and sinks in a fertilized Zea mays field.

An analytical model was developed to describe in-canopy vertical distribution of ammonia (NH(3)) sources and sinks and vertical fluxes in a fertilized agricultural setting using measured in-canopy mean NH(3) concentration and wind speed profiles. This model was applied to quantify in-canopy air-surface exchange rates and above-canopy NH(3) fluxes in a fertilized corn (Zea mays) field. Modeled air-canopy NH(3) fluxes agreed well with independent above-canopy flux estimates. Based on the model results, the urea fertilized soil surface was a consistent source of NH(3) one month following the fertilizer application, whereas the vegetation canopy was typically a net NH(3) sink with the lower portion of the canopy being a constant sink. The model results suggested that the canopy was a sink for some 70% of the estimated soil NH(3) emissions. A logical conclusion is that parametrization of within-canopy processes in air quality models are necessary to explore the impact of agricultural field level management practices on regional air quality. Moreover, there are agronomic and environmental benefits to timing liquid fertilizer applications as close to canopy closure as possible. Finally, given the large within-canopy mean NH(3) concentration gradients in such agricultural settings, a discussion about the suitability of the proposed model is also presented.

Agronomic and economic viability of Miscanthus x giganteus as a novel biofuel in the Maryland climate

Gemstone Team Biofuels

Naturaleza de la fertilización y calidad de hortalizas

p.123-134

Utilización de un residuo mineral de baja ley en fósforo como fertilizante

p.43-49

Oceans and Human Health (OHH): a European Perspective from the Marine Board of the European Science Foundation (Marine Board-ESF)

The oceans and coastal seas provide mankind with many benefits including food for around a third of the global population, the air that we breathe and our climate system which enables habitation of much of the planet. However, the converse is that generation of natural events (such as hurricanes, severe storms and tsunamis) can have devastating impacts on coastal populations, while pollution of the seas by pathogens and toxic waste can cause illness and death in humans and animals. Harmful effects from biogenic toxins produced by algal blooms (HABs) and from the pathogens associated with microbial pollution are also a health hazard in seafood and from direct contact with water. The overall global burden of human disease caused by sewage pollution of coastal waters has been estimated at 4 million lost person-years annually. Finally, the impacts of all of these issues will be exacerbated by climate change. A holistic systems approach is needed. It must consider whole ecosystems, and their sustainability, such as integrated coastal zone management, is necessary to address the highly interconnected scientific challenges of increased human population pressure, pollution and over-exploitation of food (and other) resources as drivers of adverse ecological, social and economic impacts. There is also an urgent and critical requirement for effective and integrated public health solutions to be developed through the formulation of politically and environmentally meaningful policies. The research community required to address "Oceans & Human Health" in Europe is currently very fragmented, and recognition by policy makers of some of the problems, outlined in the list of challenges above, is limited. Nevertheless, relevant key policy issues for governments worldwide include the reduction of the burden of disease (including the early detection of emerging pathogens and other threats) and improving the quality of the global environment. Failure to effectively address these issues will impact adversely on efforts to alleviate poverty, sustain the availability of environmental goods and services and improve health and social and economic stability; and thus, will impinge on many policy decisions, both nationally and internationally. Knowledge exchange (KE) will be a key element of any ensuing research. KE will facilitate the integration of biological, medical, epidemiological, social and economic disciplines, as well as the emergence of synergies between seemingly unconnected areas of science and socio-economic issues, and will help to leverage knowledge transfer across the European Union (EU) and beyond. An integrated interdisciplinary systems approach is an effective way to bring together the appropriate groups of scientists, social scientists, economists, industry and other stakeholders with the policy formulators in order to address the complexities of interfacial problems in the area of environment and human health. The Marine Board of the European Science Foundation Working Group on "Oceans and Human Health" has been charged with developing a position paper on this topic with a view to identifying the scientific, social and economic challenges and making recommendations to the EU on policy-relevant research and development activities in this arena. This paper includes the background to health-related issues linked to the coastal environment and highlights the main arguments for an ecosystem-based whole systems approach.

Polycyclic aromatic hydrocarbons (PAHS) (I): Toxicity, population exposure and involved foods

Food is one of the main exogenous sources of genotoxic compounds. In heated food products, polycyclic aromatic hydrocarbons (PAHs) represent a priority group of genotoxic, mutagenic and/or carcinogenic chemical pollutants with adverse long-term health effects. People can be exposed to these compounds through different environments and via various routes: inhalation, ingestion of foods and water and even percutaneously. The presence of these compounds in food may be due to environmental contamination, to industrial handling and processing of foods and to oil processing and refining. The highest levels of these compounds are found in smoked foods, in seafood which is found in polluted waters, in grilled meats and, to a lesser extent, in vegetable fats and oils. Lower levels of PAHs are found in vegetables and in cereals and its products.

Pilot-scale evaluation of the application of low pH-inducible polyphosphate accumulation to the biological removal of phosphate from wastewaters.

To investigate the possible biotechnological application of the phenomenon of low pH-inducible phosphate uptake and polyphosphate accumulation, previously reported using pure microbial cultures and under laboratory conditions, a 2000 L activated sludge pilot plant was constructed at a municipal sewage treatment works. When operated as a single-stage reactor this removed more than 60% of influent phosphate from primary settled sewage at a pH of 6.0, as opposed to approximately 30% at the typical operational pH for the works of 7.0-7.3-yet without any deleterious effect on other treatment parameters. At these pH values the phosphorus content of the sludge was, respectively, 4.2% and 2.0%. At pH 6.0 some 33.9% of sludge microbial cells were observed to contain polyphosphate inclusions; the corresponding value at pH 7.0 was 18.7%. Such a process may serve as a prototype for the development of alternative biological and chemical options for phosphate removal from wastewaters.

Nitrogen-15 and Oxygen-18 Natural Abundance of Potassium Chloride Extractable Soil Nitrate Using the Denitrifier Method

In agroecosystems, most isotopic investigations of NO3- involve the use of tracers that are artificially enriched in 15N. Although the dual isotope composition of NO3-— d15N and d18O is especially beneficial for understanding the origin and fate of NO3-, its use for KCl-extractable soil NO3- has been hampered by the lack of a suitable analytical technique. Our objective was to test whether the denitrifier method, whereby NO3- is reduced to N2O before mass spectrometric analysis, can be used to determine the N and O isotopic composition of NO3- from 2 M KCl soil extracts. Several internationally accepted NO3- standards were dissolved in 2 M KCl, the conventional extractant for soil inorganic N, and inoculated with the bacterial strain Pseudomonas aureofaciens (ATCC no. 13985). The standard deviation of the NO3- standards analyzed did not exceed 0.2‰ for d15N and 0.3‰ for d18O values. After appropriate corrections, differences between our measured and consensus d15N and d18O values of standard NO3- generally were within the standard deviations given for the consensus values. Both d15N and d18O values were reproducible among separate analytical runs. The method was also tested on genuine 2 M KCl extracts from unfertilized and fertilized soils. Depending on N fertilization, the soils had distinct d15N and d18O values, which were attributed to amendment with NH4NO3 fertilizer. Hence, our data indicate that the denitrifier method provides a fast, reliable, precise, and accurate way of simultaneously analyzing the natural abundances of 15N and 18O in KCl-extractable soil NO3-.