A importância da estimativa das necessidades hídricas das culturas para uma boa gestão da rega.

A necessidade dos agricultores em se adaptarem às tendências do mercado e ao mesmo tempo aumentarem a sua capacidade produtiva, tem conduzido a um aumento significativo das áreas regadas em Portugal. A construção de novas barragens, como a do Alqueva, e alguns incentivos que as políticas agrícolas têm dado à aquisição de equipamentos de rega e à realização de culturas regadas, também têm contribuído para esta expansão do regadio. Porém, não basta adquirir um bom sistema de rega para se conseguir produzir de um modo eficiente uma qualquer cultura de regadio. É necessário saber gerir o sistema para poder fornecer à cultura a quantidade de água que ela necessita nas diferentes fases do seu ciclo vegetativo, tentando ao mesmo tempo maximizar a eficiência de aplicação dessa mesma água de acordo com as características do equipamento e do solo onde a cultura está instalada

Bacterial enzymatic activity and bioavailability of heavy metals in sediments from Boa Viagem Beach (Guanabara Bay)

This study focuses on the quality of the organic matter that reaches the sediment from Boa Viagem Beach and through the evaluation of the total bacterial count, the electron transport system activity (ETSA), the esterase activity (EST), as well as the protein and the organic matter contents. Seasonal variations of organic matter, protein content and the number of bacteria were particularly notable in the summer. ETSA reached a maximum of 7.48 µl O2 h-1 g-1 in the summer. EST activity presented a different pattern once it reached a maximum of 0.17 µg fluorescein h-1 g-1 in the winter. The temporal variation of ETSA and EST activity indicated that biopolymers predominated in the winter, and oligomers or monomers predominated in the summer. These results suggest that organic carbon turnover is more likely to be controlled by organic matter quality. The heavy metals concentrations, especially for Cu, Zn, Ni and Cr, indicated absence of the inhibition of dehydrogenase activity, and they are not bioavailable in the EC50 valuesO trabalho enfoca a qualidade da matéria orgânica do sedimento da Praia da Boa Viagem, avaliando-se a contagem de bactérias, a atividade do sistema transportador de elétrons (ETSA), a atividade de esterases (EST) e a concentração de proteína e matéria orgânica. Variação sazonal de matéria orgânica, de proteína e número de bactérias foi significativo no verão. ETSA apresentou maior valor no verão, 7.48 µl O2 h-1 g-1. A EST foi maior no inverno, chegando a 0.17 µg fluorescein h-1 g-1. A variação temporal de ETSA e EST indicaram que biopolímeros predominaram no inverno e oligômeros e monômeros, no verão. Estes resultados sugerem que a transformação do carbono orgânico é controlado pela qualidade da matéria orgânica. As concentrações dos metais, especialmente Cu, Zn, Ni and Cr, indicam ausência de inibição da atividade das desidrogenase pois não estão biodisponíveis na concentração EC50

Comparison of Four Natural Ventilation Systems in a Mediterranean Greenhouse

Ventilation is one of the most important tools for controlling the greenhouse climate, influencing the environmental conditions such as temperature, humidity and carbon dioxide concentration, which affect the development and production of the crop. Natural ventilation is the result of the action of two natural forces, wind and thermal buoyancy. The main objectives of this study were to: 1). compare the behaviour of internal air parameters such as air temperature and humidity in a greenhouse with different management of natural ventilation and 2). calibrate and validate a climatic model. The study was based on experiments carried out in a greenhouse located at the ETSIA-Universidad Politecnica de Madrid, with floor area of 132 m2. The greenhouse was equipped with roof and side vents along the entire length. Four different systems (S) were studied, both roof and side openings (S1, A1=21.3 m2) and only roof openings (S2, A2=12.3 m2; S3, A3=7.9 m2 and S4, A4=4.4 m2). External and internal climatic parameters, such as air temperature, relative humidity, solar radiation and wind speed were measured and recorded using a data logger. All the data were recorded during several days for the different systems. Data of internal air temperature and water vapour pressure difference were analysed and compared between the different systems. In this study, ventilation rates were calculated using a model based on wind and buoyancy forces, assuming that total ventilation is due to the combined effect of both natural forces. Ventilation rates were then related to internal air conditions. Temperature differences between inside and outside varied within a range of 3.3 ºC (S1) and 10.6 ºC (S4), presenting an inverse proportionality to the ventilation area. The vapour pressure difference presented the highest value (0.111 kPa) for S2 and the lowest (0.011 kPa) for S3. A climatic model, based on energy and mass balances, allowing the prediction of internal air temperature and relative humidity, was calibrated and validated for the different ventilation systems. Partial data were used to calibrate the model and another set of data from different periods was used for model validation. Measured and predicted data were comparatively close

Hypercysteinemia, a potential risk factor for central obesity and related disorders in Azores, Portugal

In Azores, the standardized mortality rate for coronary artery disease (CAD) is nearly the double when compared to mainland Portugal. The aim of this study was to compare the prevalence of conventional CAD risk factors, as well as the plasma aminothiol profile (and its major determinants), between two groups of healthy subjects from Ponta Delgada (in Azores) and Lisbon (in mainland) cities, searching for precocious biomarker(s) of the disease. The study groups consisted of 101 healthy volunteers from Ponta Delgada (PDL) and 121 from Lisbon, aged 20-69 years. No differences in the prevalence of classical CAD risk factors were found between the study groups, except in physical inactivity and related central obesity, which were both higher in PDL men than in those from Lisbon. Hypercysteinemia, which seems to result from sulfur-rich amino acid diets and/or vitamin B12 malabsorption, revealed to be significantly more prevalent in PDL vs. Lisbon subjects (18% vs. 4%, P=0.001), namely, in male gender. Moreover, plasma Cys levels predicted waist circumference (β coefficient = 0.102, P=0.032) and concomitant central obesity and were also associated with insulin resistance. Nevertheless, hyperhomocysteinemia prevalence was similar in both groups, despite the fact that PDL subjects exhibited a higher rate of vitamin B12 deficiency compared to those from Lisbon (19% vs. 6%, P=0.003). Owing to the nature of this study design, a cause-effect relationship between high plasma Cys levels and central obesity or CAD risk could not be derived, but results strongly suggest that hypercysteinemia is a potential risk factor for metabolic disorders, i.e., obesity and insulin resistance, and CAD in Azores, a hypothesis that asks for confirmation through further large prospective studies.)is work was supported by the Regional Government of the Azores (FRCT), Portugal (PhD grant number M3.1.2/F/017/ 2011 to AL, postdoctoral grant number M3.1.7/F/020/2011 to RF, and research project number M1.1.C/I/001/2016).info:eu-repo/semantics/publishedVersio

A modernização agropecuária nas microrregiões do estado de Minas Gerais

Este estudo objetivou identificar e caracterizar grupos distintos de microrregiões homogêneas quanto ao grau de modernização agropecuária no Estado de Minas Gerais. Para tanto foram empregadas as técnicas de análise fatorial e de análise de agrupamento, a fim de obter os fatores que refletem o padrão tecnológico e cujas relações permitam formar grupos de microrregiões semelhantes. Foram identificados 10 grupos distintos de microrregiões homogêneas, cada um possuindo combinação distinta dos fatores encontrados e que reflete o seu nível tecnológico. Os grupos encontrados constituem informação preliminar para aplicação localizada de políticas de apoio ao setor, bem como para a tomada de decisão por parte dos agentes da iniciativa privada

Implementing the World Mental Health Survey Initiative in Portugal – rationale, design and fieldwork procedures

Background: The World Mental Health Survey Initiative was designed to evaluate the prevalence, the correlates, the impact and the treatment patterns of mental disorders. This paper describes the rationale and the methodological details regarding the implementation of the survey in Portugal, a country that still lacks representative epidemiological data about psychiatric disorders. Methods: The World Mental Health Survey is a cross-sectional study with a representative sample of the Portuguese population, aged 18 or older, based on official census information. The WMH-Composite International Diagnostic Interview, adapted to the Portuguese language by a group of bilingual experts, was used to evaluate the mental health status, disorder severity, impairment, use of services and treatment. Interviews were administered face-to-face at respondent’s dwellings, which were selected from a nationally representative multi-stage clustered area probability sample of households. The survey was administered using computer-assisted personal interview methods by trained lay interviewers. Data quality was strictly controlled in order to ensure the reliability and validity of the collected information. Results: A total of 3,849 people completed the main survey, with 2,060 completing the long interview, with a response rate of 57.3%. Data cleaning was conducted in collaboration with the WMHSI Data Analysis Coordination Centre at the Department of Health Care Policy, Harvard Medical School. Collected information will provide lifetime and 12-month mental disorders diagnoses, according to the International Classification of Diseases and to the Diagnostic and Statistical Manual of Mental Disorders. Conclusions: The findings of this study could have a major influence in mental health care policy planning efforts over the next years, specially in a country that still has a significant level of unmet needs regarding mental health services organization, delivery of care and epidemiological research

Mutual information rate and bounds for it

The amount of information exchanged per unit of time between two nodes in a dynamical network or between two data sets is a powerful concept for analysing complex systems. This quantity, known as the mutual information rate (MIR), is calculated from the mutual information, which is rigorously defined only for random systems. Moreover, the definition of mutual information is based on probabilities of significant events. This work offers a simple alternative way to calculate the MIR in dynamical (deterministic) networks or between two data sets (not fully deterministic), and to calculate its upper and lower bounds without having to calculate probabilities, but rather in terms of well known and well defined quantities in dynamical systems. As possible applications of our bounds, we study the relationship between synchronisation and the exchange of information in a system of two coupled maps and in experimental networks of coupled oscillators

Screening for angiotensin I-converting enzyme (ACE) inhibitory activity of enzymatic hydrolysates obtained from Azorean macroalgae

As part of ongoing studies into the isolation of antihypertensive peptides, 12 common macroalgae species from Azores were investigated for their potential angiotensinconverting enzyme (ACE) inhibitory properties. After optimization of enzymatic hydrolysis conditions, the anti-ACE activity was determined by high performance liquid chromatography (HPLC). The species under study include four Rhodophyta (Gelidium microdon, Osmundea pinnatifida, Porphyra sp. and Pterocladiella capillacea), four Chlorophyta (Chaetomorpha linum, Codium adhaerens, Ulva compressa and Ulva rigida) and four Heterokontophyta (Cystoseira humilis, Fucus spiralis, Padina pavonica and Sargassum cymosum). The bromelain hydrolysates derived from P. capillacea, Porphyra sp., F. spiralis, U. compressa, O. pinnatifida and U. rigida were the most active presenting an ACE inhibitory activity of 48.73 ± 1.58%, 50.96 ± 1.82%, 56.77 ± 1.80%, 59.80 ± 0.95%, 62.59 ± 1.60% and 65.68 ± 0.72%, respectively. These results suggest that some macroalgae from the littoral Azorean sea are potential sources of powerful ACE inhibitor peptides, with potential impact on public health, particularly on the hypertensive patients. These features make these algae valuable to the regional economy and may also provide an incentive for marine biodiversity conservation and valuation of marine algal resources

Optical Current Sensors for High Power Systems: A Review

The intrinsic advantages of optical sensor technology are very appealing for high voltage applications and can become a valuable asset in a new generation of smart grids. In this paper the authors present a review of optical sensors technologies for electrical current metering in high voltage applications. A brief historical overview is given together with a more detailed focus on recent developments. Technologies addressed include all fiber sensors, bulk magneto-optical sensors, piezoelectric transducers, magnetic force sensors and hybrid sensors. The physical principles and main advantages and disadvantages are discussed. Configurations and strategies to overcome common problems, such as interference from external currents and magnetic fields induced linear birefringence and others are discussed. The state-of-the-art is presented including commercial available systems.info:eu-repo/semantics/publishedVersio