Nitrate ammonification and its relationship to the accumulation of ammonium in a Vertisol subsoil

High concentrations of ammonium ( up to 270 kg N/ha) have been observed in a Vertisol soil below 1 m depth near Warra in south-east Queensland. This study examined the possibility that increased water movement into the subsoil after the removal of native vegetation, and a subsequent increase in periods of waterlogging, could have triggered nitrate ammonification and be responsible for the production of ammonium. Two incubation experiments were conducted to test this hypothesis. The first involved the incubation of repacked cores that had been amended with 30 mg N/kg of 5 atom% N-15 nitrate under low oxygen conditions for a period of 360 days. Over this time period the N-15 enrichment of the exchangeable ammonium fraction was monitored in order to detect any reduction of nitrate to ammonium. The second experiment involved the incubation of soil amended with 30 mg N/ kg of 5 atom% N-15 nitrate under waterlogged and low oxygen conditions for 75 days. During this period the redox potential of the soil was monitored using a field test to determine if reducing conditions would develop in this soil over a period of waterlogging, combined with the monitoring of any nitrate reduction to ammonium. The results of these experiments indicated that a small amount of nitrate ammonification (< 0.1 mg N/ kg) could be observed in the Warra subsoil, but that unless the rate of reduction were to significantly increase with time, this could not account for the accumulation of ammonium observed in the field. The environmental conditions that would make either dissimilatory or abiotic nitrate ammonification favourable were not observed to develop. Consequently, it has been concluded that the observed nitrate ammonification occurred via an assimilatory pathway. Due to the low rate of microbial activity in this subsoil it is considered unlikely that this process was responsible for the subsoil ammonium accumulation at Warra.

Mid- to Late-Holocene estuarine infilling processes studied by radiocarbon dates, high resolution seismic and biofacies at Vitoria Bay, Espirito Santo, Southeastern Brazil

A Baía de Vitória é um estuário com 20 km de comprimento, morfologicamente estreito, com um regime de micromaré e, como outros estuários modernos, formado durante a última transgressão pós-glacial. A morfologia de fundo do estrato estuarino é caracterizada por um canal natural principal limitado por planícies de maré com manguezais desenvolvidos. Datações de radiocarbono originais foram obtidas para a área. Cinco idades de radiocarbono estendendo-se de 1.010 a 7.240 anos AP foram obtidas através de dois testemunhos de sedimento, representando uma sequência estratigráfica de 5 m de espessura. Os resultados indicam que até aproximadamente 4.000 anos cal. AP, as condições ambientais da Baía de Vitória eram ainda de uma baía aberta, com uma conexão livre e aberta com águas marinhas. Durante os últimos 4.000 anos a baía experimentou uma fase de regressão importante, tornando-se mais restrita em termos de circulação da água do mar e provavelmente aumentando a energia de marés. Três superfícies estratigráficas principais foram reconhecidas, limitando fácies transgressiva, transgressiva/nível de mar alto e regressiva. A morfologia do canal atual representa um diastema de maré, mostrando fácies regressivas truncadas e erodidas. Biofácies de foraminíferos, passando de ambiente marinho para ambiente salobro e de manguezais em planície de maré confirmam a interpretação sismoestratigráfica. A ausência de biofácies de mangue em um dos dois testemunhos é tambémuma indicação de ravinamento de maré atual.

Estudo da corrosão dos aços AISI 1010 e AISI 316L em soluções com elevado teor de cloreto e em ácido naftênico

A mudança no mercado global do petróleo nos últimos anos, com o declínio das reservas de óleo leve, têm forçado a busca por novos campos petrolíferos em ambientes mais remotos, como nos campos localizados na camada pré-sal, e a exploração de óleos pesados que possuem elevado teor de ácidos naftênicos. Isso acarreta em grandes desafios para a previsão do desempenho de materiais frente às novas condições ambientais em que estão inseridos. No presente trabalho, o comportamento da corrosão do aço carbono AISI 1010 e do aço inoxidável AISI 316L foi estudado em soluções aquosas com elevado teor de cloreto e em solução de ácido naftênico ciclopentanóico a fim de ter melhor entendimento da ação dessas espécies no processo de corrosão e simular a corrosão pela água de produção na indústria petrolífera. Foram aplicadas as técnicas de potencial de circuito aberto, polarização potenciodinâmica, voltametria cíclica, espectroscopia de impedância eletroquímica, espectroscopia Raman, microscopia eletrônica de varredura e microscopia de força atômica, usadas, em cada caso, de acordo com a conveniência. O aumento da [Cl-] na faixa de 1,2–2,8 mol.L-1 não altera os processos catódicos e anódicos perto do Ecorr para os aços AISI 1010 e AISI 316L. Em condições de sobrepotenciais afastados do Ecorr, o aumento de [Cl-] aumenta os processos oxidativos de corrosão, o que é expresso pelas maiores densidades de corrente e carga anódica e aumento da perda de massa sofrida pelos eletrodos de ambos os aços. Portanto, os danos da corrosão são mais intensos quando se aumenta a [Cl-]. O aço AISI 1010 é ativo nas soluções de NaCl e a corrosão se propaga livremente de forma uniforme. Para o aço AISI 316L, uma ampla faixa de passividade pode ser vista nas soluções de NaCl; no Epit ocorre a ruptura do filme passivo e o crescimento de pites estáveis. Após 24 h de imersão em soluções de sulfato de sódio (branco) e de ácido naftênico ciclopentanóico ocorre crescimento de filme de óxido e as fases α-Fe2O3, Fe3O4 e δ-FeO(OH) foram identificadas nos espécimes de aço AISI 1010 e Fe3O4 foi identificado nos defeitos do filme prévio presente na superfície do aço AISI 316L. Os filmes formados em solução de ácido ciclopentanóico possuem menor resistência à polarização, maior rugosidade e maior taxa de corrosão quando comparado aos filmes crescidos na solução branco, para ambos os aços. A presença do ácido naftênico muda a forma como a reação de corrosão se procede e contribui para o aumento da corrosão. A corrosão naftênica foi mais pronunciada no aço carbono porque a presença dos elementos de liga no aço inox reduzem o número de sítios ativos ricos em Fe e tornam menos oportuna a ligação do Fe com o naftenato.

Qualidade fisiológica de sementes e diversidade genética de maracujazeiros cultivados em diferentes altitudes no Espírito Santo

O maracujazeiro pertence à família Passifloraceae e ao gênero Passiflora que é o mais importante economicamente. Altitudes entre 100 a 900 m são indicadas para o plantio do maracujazeiro e estudos sobre localizações geográficas distintas possibilitam expressões do genótipo, influenciadas pelas condições ambientais. O gradiente altitudinal influencia a distribuição da variação genética dentro e entre populações de plantas e a diversidade genética muda com a altitude. O presente trabalho teve como objetivo avaliar a qualidade fisiológica de sementes e a diversidade genética de maracujazeiros cultivados em diferentes altitudes do Espírito Santo. Para avaliação da qualidade fisiológica das sementes, os frutos de Passiflora spp. maduros foram colhidos em pomares localizados em altitudes baixa (0-100 m), média (>100 até 600 m) e alta (>600 m) de diferentes municípios do Espírito Santo. Os tratamentos pré-germinativos nas sementes foram: T1- escarificação física, feita manualmente com lixa d´água nº 120; T2- tratamento com ácido giberélico (GA3) na concentração de 500 mg L-1 com embebição por 24 horas e T3- sementes sem escarificação realizados nas sementes em laboratório e em casa de vegetação. Foi avaliado o envelhecimento acelerado tradicional, envelhecimento acelerado com saturação salina e deterioração controlada em sementes de maracujá amarelo sem escarificação localizado em alta altitude e as condições que apresentaram menor deterioração das sementes para aplicação às demais espécies e altitudes com os respectivos tratamentos pré-germinativos que apresentaram maiores valores de germinação e vigor em laboratório e em casa de vegetação. Assim, para as sementes do maracujá amarelo utilizou-se o tratamento sem escarificação, para sementes de maracujá roxo, a escarificação física e para as sementes de maracujá doce, o tratamento com ácido giberélico. O teste de envelhecimento acelerado com saturação salina a 43 ºC por 72 horas e deterioração controlada a 25% de umidade expostas por 24 horas diferencia as espécies nas diferentes altitudes. Sementes de maracujá amarelo e sementes localizadas em alta altitude apresentam qualidade fisiológica superior. Para a avaliação da diversidade genética foram utilizadas folhas jovens de cinco plantas matrizes de Passiflora edulis Sims f. flavicarpa Degener, P. edulis Sims e P. alata Curtis cultivadas em três altitudes (baixa, média e alta) do Espírito Santo. Para SSR foi encontrado baixo número de alelos, alta heterozigosidade esperada e altos valores de PIC e para a análise ISSR detectou um elevado número de bandas por primer e alto polimorfismo. Há maior similaridade genética entre P. edulis f. flavicarpa Deg. e P. edulis. Passiflora alata apresenta maior distância genética em relação às espécies. As populações de baixa altitude se diferenciam das demais independente da espécie e do marcador utilizado.

Weed suppression by green manure in an agroecological system

ABSTRACT Green manure promotes efficient suppression of weeds, but green manure species can exhibit distinct behaviors, depending on the environmental conditions. This study aimed to evaluate the potential of soil mulching and weed suppression by spring/summer green manure species grown in the spring/summer season, at different growth stages and after management (cut), for 90 days during the cassava crop cycle. The study was carried out in the 2010/2011 season, in a system managed under agroecological principles. The treatments consisted of different green manure species and arrangements: Crotalaria juncea, Cajanus cajan, Canavalia brasiliensis, Canavalia ensiformis, Pennisetum americanum, Crotalaria juncea and Pennisetum americanum intercropped; Mucuna aterrima, Sorghum bicolor, a mixture of all the green manures in study and a control plot under fallow. The experiment was arranged in a randomized block design with four replications. The evaluations of the soil cover either by the green manures or weeds were performed at 45, 90 and 105 days after the emergence of the green manures. The cassava crop was planted under reduced tillage system at 11 days after the cut of the green manures. The percentage of soil covered by weeds and the dry matter produced were evaluated at 30, 60 and 90 days after planting. The results showed that the green manures had a suppressive effect on weeds during their life cycle, as well as during the first months after its management (cut), composing the mulch.

Are air-borne mycotoxins a public health concern in Portugal?

Introduction - Microscopic filamentous fungi, under suitable environmental conditions, can lead to the production of highly toxic chemical substances, commonly known as mycotoxins. The most widespread and studied mycotoxins are metabolites of some genera of moulds such as Aspergillus, Penicillium and Fusarium. Quite peculiar conditions may influence mycotoxin biosynthesis, such as climate, geographical location, cultivation practices, storage and type of substrate. Toxicity has been extensively investigated for the most important mycotoxins, such as aflatoxins, ochratoxin A and Fusarium toxins, and much information derived from toxicokinetics in animal models has also been obtained. The adverse effects are mainly related to genotoxicity, carcinogenicity, mutagenicity, teratogenicity and immunotoxicity. Aim of the study - To identify fungal species able to produce important mycotoxins in different Portuguese settings.

Changes in the influence of board characterisitcs on corporate results due to the recent global financial crisis

The main purpose of this study is to analyse the changes caused by the global financial crisis on the influence of board characteristics on corporate results, in terms of corporate performance, corporate risk-taking, and earnings management. Sample comprises S&P 500 listed firms during 2002-2008. This study reveals that the environmental conditions call for different behaviour from directors to fulfil their responsibilities and suggests changes in normative and voluntary guidelines for improving good practices in the boardroom.

Cyanobacteria toxicity: potential public health impact in South Portugal populations

Cyanobacteria are prokaryotic, plantlike organisms present in lakes, recreational waters, and reservoirs, and often dominate phytoplankton communities in warm, nutrient-enriched hard waters. A stable water column rich in certain nutrients, especially nitrogen and phosphorus, is associated with favorable environmental conditions that support development of cyanobacterial population maxima or "blooms." Under specific conditions, cyanobacteria produce toxins that are responsible for acute poisoning and death of animals and humans. The main aim of this study was to correlate the presence of cyanobacteria blooms with potential toxicity to humans as a public health issue. In Portugal, seven reservoirs located in the southern region were selected and studied between 2000 and 2008. Reservoirs were characterized by physical and chemical aspects, and identification of phytoplankton communities. In the case of cyanobacterial blooms, toxins that affected the liver, nervous system, and skin were detected, namely, Microcystis aeruginosa, Aphanizomenon spp., and Oscillatoria. These findings suggest the presence of a potential risk for public health, and indicate the need to implement mitigation measures in all studied reservoirs. These measures may involve (1) water eutrophication control to avoid blooms, (2) appropriate treatment of water for human consumption, and (3) public warnings or information to those individuals that use these reservoirs for several recreational activities.

Avaliação da eco-eficiência de uma empresa de serviços: caso prático

Mestrado em Engenharia Química

The surplus value of Azorean macroalgae as health-promoting food. Protein, fiber, carbohydrates, lipids and vitamins determination

AICMA 2012 (BIT's 1st Annual International Congress of Marine Algae), World Expo Center, Dalian, China, 20-23 de Setembro.

Study of the one dimensional and transient bioheat transfer equation: Multi-layer solution development and applications

: In this work we derive an analytical solution given by Bessel series to the transient and one-dimensional (1D) bioheat transfer equation in a multi-layer region with spatially dependent heat sources. Each region represents an independent biological tissue characterized by temperature-invariant physiological parameters and a linearly temperature dependent metabolic heat generation. Moreover, 1D Cartesian, cylindrical or spherical coordinates are used to define the geometry and temperature boundary conditions of first, second and third kinds are assumed at the inner and outer surfaces. We present two examples of clinical applications for the developed solution. In the first one, we investigate two different heat source terms to simulate the heating in a tumor and its surrounding tissue, induced during a magnetic fluid hyperthermia technique used for cancer treatment. To obtain an accurate analytical solution, we determine the error associated with the truncated Bessel series that defines the transient solution. In the second application, we explore the potential of this model to study the effect of different environmental conditions in a multi-layered human head model (brain, bone and scalp). The convective heat transfer effect of a large blood vessel located inside the brain is also investigated. The results are further compared with a numerical solution obtained by the Finite Element Method and computed with COMSOL Multi-physics v4.1 (c). (c) 2013 Elsevier Ltd. All rights reserved.

Efeitos da hidrodinâmica em comunidades biológicas de praias de calhau rolado em áreas marinhas protegidas

Jornadas "Ciência nos Açores – que futuro?", Ponta Delgada, 7-8 de Junho de 2013.

Shell variation in Patellid limpets: scales of spatial variability

World Congress of Malacology, Universidade dos Açores, Ponta Delgada, 21-28 de julho.

Occupational exposure to particulate matter and respiratory symptoms in Portuguese swine barn workers

Certain environmental conditions in animal and plant production have been associated with increased frequency in respiratory illnesses, including asthma, chronic bronchitis, and hypersensitivity pneumonitis, in farmers occupationally exposed in swine production. The aim of this study was to characterize particulate matter (PM) contamination in seven Portuguese swine farms and determine the existence of clinical symptoms associated with asthma and other allergy diseases, utilizing the European Community Respiratory Health Survey questionnaire. Environmental assessments were performed with portable direct-reading equipment, and PM contamination including five different sizes (PM0.5, PM1.0, PM2.5, PM5.0, PM10) was determined. The distribution of particle size showed the same trend in all swine farms, with high concentrations of particles with PM5 and PM10. Results from the questionnaire indicated a trend such that subjects with diagnosis of asthma were exposed to higher concentrations of PM with larger size (PM2.5, PM5, and PM10) while subjects with sneezing, runny nose, or stuffy nose without a cold or flu were exposed to higher concentrations of PM with smaller size (PM0.5 and PM1). Data indicate that inhalation of PM in swine farm workers is associated with increased frequency of respiratory illnesses.

Mould and yeast identification in archival settings: preliminary results on the use of traditional methods and molecular biology options in Portuguese archives

This project was developed to fully assess the indoor air quality in archives and libraries from a fungal flora point of view. It uses classical methodologies such as traditional culture media – for the viable fungi – and modern molecular biology protocols, especially relevant to assess the non-viable fraction of the biological contaminants. Denaturing high-performance liquid chromatography (DHPLC) has emerged as an alternative to denaturing gradient gel electrophoresis (DGGE) and has already been applied to the study of a few bacterial communities. We propose the application of DHPLC to the study of fungal colonization on paper-based archive materials. This technology allows for the identification of each component of a mixture of fungi based on their genetic variation. In a highly complex mixture of microbial DNA this method can be used simply to study the population dynamics, and it also allows for sample fraction collection, which can, in many cases, be immediately sequenced, circumventing the need for cloning. Some examples of the methodological application are shown. Also applied is fragment length analysis for the study of mixed Candida samples. Both of these methods can later be applied in various fields, such as clinical and sand sample analysis. So far, the environmental analyses have been extremely useful to determine potentially pathogenic/toxinogenic fungi such as Stachybotrys sp., Aspergillus niger, Aspergillus fumigatus, and Fusarium sp. This work will hopefully lead to more accurate evaluation of environmental conditions for both human health and the preservation of documents.