Influência da morfologia do terreno nas características do solo em terrenos agrícolas do Alentejo – aplicação de classificações geomorfométricas.

Neste artigo utiliza-se um Modelo de Elevação Digital (MED) para elaborar e comparar diferentes classificações da morfologia do terreno quanto ao seu potencial para a diferenciação da espessura e da textura do solo. As classificações baseiam-se em observações de campo (UTobs e PEobs-L) ou no cálculo de variáveis geomorfométricas num MED (UTx, UTx-L e PEx-L). Aplicam-se a uma área localizada a 80 km a Este de Évora, próximo de Terena, Alandroal, numa parcela cultivada com milho regado por rampa rotativa desde 1994 e com uma morfologia ondulada em que os declives variam entre 1% e 28%. Fez-se o levantamento topográfico baseado num sistema de posicionamento global, a elaboração de um MED e o cálculo de vários parâmetros geomorfométricos de âmbito local e regional. A amostragem do solo incidiu em dois blocos (A e B), segundo uma malha relativamente regular, recorrendo a uma sonda mecânica cilíndrica com 87 mm de diâmetro e 120 cm de profundidade. Os resultados da espessura do solo e da textura da camada 0-20 cm de 203 sondagens são usados para avaliar a homogeneidade e a diferenciação das unidades de terreno (UT) obtidas com as classificações morfológicas. Todas as classificações testadas se revelaram pouco eficientes a diferenciar os solos quanto à granulometria. Os resultados foram melhores na diferenciação das variáveis de espessura, em especial a profundidade máxima observada (PMX) e a profundidade até à camada R (PR), apresentandose as classificações pela seguinte sequência qualitativa: UTobs-L > PEobs-L > PEx-L. As classificações por observação de campo obtiveram melhores resultados, mas as classificações geomorfométricas baseadas em variáveis regionais (PEx-L) foram melhores que as baseadas em variáveis locais (UTx e UTx-L). No caso da espessura, a eliminação de UT < 100 m 2 melhorou sempre a resposta das classificações

From Assessing to Conserving biodiversity. Conceptual and Practical Challenges

This open access book features essays written by philosophers, biologists, ecologists and conservation scientists facing the current biodiversity crisis. Despite increasing communication, accelerating policy and management responses, and notwithstanding improving ecosystem assessment and endangered species knowledge, conserving biodiversity continues to be more a concern than an accomplished task. Why is it so? The overexploitation of natural resources by our species is a frequently recognised factor, while the short-term economic interests of governments and stakeholders typically clash with the burdens that implementing conservation actions imply. But this is not the whole story. This book develops a different perspective on the problem by exploring the conceptual challenges and practical defiance posed by conserving biodiversity, namely: on the one hand, the difficulties in defining what biodiversity is and characterizing that “thing” to which the word ‘biodiversity’ refers to; on the other hand, the reasons why assessing biodiversity and putting in place effective conservation actions is arduous. ; Features essays that are explicitly critical of the species approach to biodiversity Presents bio-philosophical perspectives on the interaction between biodiversity’s units, levels, and scales Serves as an interdisciplinary contribution to the emergent field of biodiversity studie

Delineation of management zones using mobile measurements of soil apparent electrical conductivity and multivariate geostatistical techniques

Site-specific management promotes the identification and management of areas within the field, which represent subfield regions with homogeneous characteristics (management zones). However, determination of subfield areas is difficult because of the complex combination of factors which could affect crop yield. One possibility to capture yield variability is the use of soil physical properties to define the management zones as they are related to plant available water. With the aim of characterizing the spatial variability of the main soil physical variables and using this information to determine potential management zones, soil samples were taken from 70 locations in a 33-ha field in Badajoz, southwestern Spain. Firstly, accurate spatial distribution maps of the soil attributes were generated by using regression kriging as the most suitable algorithm in which exhaustive secondary information on soil apparent electrical conductivity (ECa) was incorporated. ECa measurements were carried out with a Veris 3100 operating in both shallow (0–30 cm), ECs, and deep (0–90 cm), ECd,mode. Clay, coarse sand and fine sand were the soil physical properties which exhibited higher correlation with ECa (positively correlated with the finer texture component, clay, and negatively correlated with the coarser ones, coarse and fine sands), particularly with ECs. Thus, this was the secondary variable used to obtain the kriged maps. Later, principal component analysis and fuzzy cluster classification were performed to delineate management zones, resulting in two subfields to be managed separately. This number of subfields was determined using the fuzzy performance index and normalized classification entropy as the way to optimize the classification algorithm

Use of CPAP to Reduce Arterial Stiffness in Moderate-to-Severe Obstructive Sleep Apnoea, Without Excessive Daytime Sleepiness (STIFFSLEEP): an Observational Cohort Study Protocol

INTRODUCTION: Sleepiness is a cardinal symptom in obstructive sleep apnoea (OSA) but most patients have unspecific symptoms. Arterial stiffness, evaluated by pulse wave velocity (PWV), is related to atherosclerosis and cardiovascular (CV) risk. Arterial stiffness was reported to be higher in patients with OSA, improving after treatment with continuous positive airway pressure (CPAP). This study aims to assess whether the same effect occurs in patients with OSA and without sleepiness. METHODS AND ANALYSIS: This observational study assesses the CV effect of CPAP therapy on a cohort of patients with moderate-to-severe OSA; the effect on the subcohorts of sleepy and non-sleepy patients will be compared. A systematic and consecutive sample of patients advised CPAP therapy will be recruited from a single outpatient sleep clinic (Centro Hospitalar de Lisboa Central-CHLC, Portugal). Eligible patients are male, younger than 65 years, with confirmed moderate-to-severe OSA and apnoea-hypopnea index (AHI) above 15/hour. Other sleep disorders, diabetes or any CV disease other than hypertension are exclusion criteria. Clinical evaluation at baseline includes Epworth Sleepiness Scale (ESS), and sleepiness is defined as ESS above 10. OSA will be confirmed by polygraphic study (cardiorespiratory, level 3). Participants are advised to undertake an assessment of carotid-femoral PWV (cf-PWV) and 24 hours evaluation of ambulatory blood pressure monitoring (ABPM), at baseline and after 4 months of CPAP therapy. Compliance and effectiveness of CPAP will be assessed. The main outcome is the variation of cf-PWV over time

Financing decisions of portuguese micro-enterprises

This paper seeks to analyze the sources of finance and capital structure of a sample of 131 small firms in Portugal, in the districts of Vila Real, Bragança, Guarda and Castelo Branco, for the period 2005 to 2009. The firms were randomly selected, and the data were collected from the accounting documents prepared for fiscal purpose. Due to the firms’ different capital structures, we divided the research sample in three sub-samples as a function of negative, near zero and positive working capital. The importance of funding sources was measured by the dependent variable of medium-long term sources, while capital structure was assessed through the dependent variables of permanent capital/total assets, non-current liabilities/total assets. The independent variables considered were firm growth, non-current asset ageing and return on equity. For data processing, we used a multi-variate linear regression, taking the mean values of each variable in the period 2005 to 2009. We found that the medium-long term growth of the firms is financed by sources of finance with the same maturity, concluding that firms follow the principle of minimum financial balance. The negative relationship between medium-long term sources and return on equity, allows us to conclude that firms follow the Pecking Order Theory. Non-current asset ageing has a positive relationship with the ratio of capital structure, meaning that older firms tend to have a higher level of permanent capital. Additionally, these results allow us to conclude that, although developed primarily for large enterprises, capital structure theories are also applicable to the micro firms analyzed

Decisões de financiamento das micro empresas nacionais

Este trabalho tem como objectivo analisar as fontes de financiamento e a estrutura de capital de uma amostra de 131 micro empresas de Portugal, para o período de 2005-2009. Verificamos que o crescimento de m/l-prazo, das empresas é financiado por intermédio de origens de fundos com a mesma maturidade, concluindo se que as empresas seguem a teoria do equilíbrio financeiro mínimo. A relação negativa, entre as origens de médio longo prazo e a rendibilidade dos capitais próprios, leva-nos a concluir que as empresas seguem a teoria pecking order. As empresas mais velhas tendem a apresentar uma maior prevalência de capitais permanentes

Permanent-magnets linear actuators applicability in automobile active suspensions

Significant improvements in automobile suspension performance are achieved by active systems. However, current active suspension systems are too expensive and complex. Developments occurring in power electronics, permanent magnet materials, and microelectronic systems justifies analysis of the possibility of implementing electromagnetic actuators in order to improve the performance of automobile suspension systems without excessively increasing complexity and cost. In this paper, the layouts of hydraulic and electromagnetic active suspensions are compared. The actuator requirements are calculated, and some experimental results proving that electromagnetic suspension could become a reality in the future are shown