38986 research outputs found
Sort by
The Social Distribution of Public Debt in Portugal, 1529-1680
No full textEste artigo analisa a distribuição social da dívida pública portuguesa entre 1529–1557
e 1641–1682, questionando até que ponto o sistema de dívida se baseou em relações
pessoais. Uma série recentemente compilada sobre as características socioeconómicas
dos credores da monarquia portuguesa revela uma mudança ao longo do tempo:
de uma elite formada por nobres e oficiais régios, no século XVI, para uma base social
mais ampla, em meados do século XVII, quando instituições e negociantes entraram
no mercado da dívida soberana. Verifica-se que a alteração da distribuição social da
dívida foi o resultado de duas operações de redução das taxas de juro e de uma campanha
de angariação de fundos, a qual envolveu um certo grau de repressão financeira
Maternal dietary exposure to mycotoxin aflatoxin B1 promotes intestinal immune alterations and microbiota modifications increasing infection susceptibility in mouse offspring
No full textMycotoxins are secondary metabolites produced by fungi occurring in food that are toxic to animals and humans. Early-life mycotoxins exposure has been linked to diverse pathologies. However, how maternal exposure to mycotoxins impacts on the intestinal barrier function of progeny has not been explored. Here, exposure of pregnant and lactating C57Bl/6J female mice to aflatoxin B1 (AFB1; 400 μg/kg body weight/day; 3 times a week) in gelatine pellets, from embryonic day (E)11.5 until weaning (postnatal day 21), led to gut immunological changes in progeny. The results showed an overall increase of lymphocyte number in intestine, a reduction of expression of epithelial genes related to microbial defence, as well as a decrease in cytokine production by intestinal type 2 innate lymphoid cells (ILC2). While susceptibility to chemically induced colitis was not worsened, immune alterations were associated with changes in gut microbiota and with a higher vulnerability to infection by the protozoan Eimeria vermiformis at early-life. Together these results show that maternal dietary exposure to AFB1 can dampen intestinal barrier homeostasis in offspring decreasing their capability to tackle intestinal pathogens. These data provide insights to understand AFB1 potential harmfulness in early-life health in the context of intestinal infections
Limestones durability study on salt crystallisation: An integrated approach
No full textLimestones are often used as building stones in contemporary architecture. Salt weathering is one of the main threats affecting this lithology. In this study, two Portuguese limestones (Branco Real and Lioz Coral) were subjected to laboratory salt crystallisation cycles by reconsidering the normative EN 12370 (Determination of the resistance to crystallisation of salts). The proposed test method consisted of 2 h of immersion in a 14 % solution of sodium sulphate decahydrate followed by 22 h drying at 40◦C instead of 105 ◦C imposed by the normative. A series of physical/ aesthetic parameters (e.g. CIE L*a*b* colour coordinates, roughness, weight variation), miner- alogical and geochemical analysis (Optical microscopy, XRD and SEM) and mechanical properties (Leeb-D hardness, ultrasound P-wave velocity and uniaxial compressive strength) were evaluated before, and after salt crystallisation cycles. Results underline the importance of salt crystallisation action and its impact on stones durability, considering the stone fabric, porosity and structure. The appearance of efflorescences, colour changes, increase of roughness, weight gain or loss, decrease of hardness, changes in p-wave speed and uniaxial compressive strength were detected even at more realistic testing conditions with a lower drying temperature
Aging of Limestones and Silane–Siloxane-Based Protective Hydrophobics: The Impact of Heating–Cooling and Freeze–Thaw Cycles
No full textStones are traditionally used in construction and architectural applications as building elements due to their aesthetic and technical/structural performance. Like other environmental factors (rain, humidity, moisture, salt presence, biological activity, etc.), heating–cooling and freeze–thaw cycles significantly threaten the longevity of stone materials. Hence, considering the socio-economic and cultural value of stones, preventive actions such as hydrophobic coatings are applied to prevent or mitigate damage. The scope of this study is the performance assessment of limestones with different characteristics and the efficiency of various commercial silane/siloxane-based hydrophobic coatings when exposed to thermal variation and freeze–thaw. For that purpose, the standards EN 14066:2013 (determination of resistance to aging by thermal shock) and EN 12371:2010 (determination of frost resistance) were followed. Open porosity and static contact angles were estimated to assess the stone durability and water protection capabilities of the hydrophobics. Additionally, sound speed propagation velocity, quality of building material index, elastic modulus and flexural strength were measured to evaluate the variation of mechanical properties. Static contact angle revealed that the coatings maintained an efficient level of hydrophobicity even after thermal-shock and freeze–thaw weathering tests. The study also revealed a critical interaction between freeze–thaw cycles, hydrophobic coatings and structural integrity of the stones, mostly on more porous ones. When they are subjected to harsh environmental conditions, untreated porous limestones keep structural cohesion, allowing for the natural absorption and release of water during freezing and thawing. On the contrary, when limestones are treated, the hydrophobic coatings can moderately obstruct the water release due to the partial saturation of the porous framework by the products. It also probably resulted from the different mechanical behavior between the inner matrix and layer of stone coated, resulting in a premature breakout and mechanical damage of the ston
Efeitos de uma intervenção psicomotora mediada pela relaxação nos indicadores fisiológicos e psicológicos em cuidadores formais: estudos caso
No full textAtualmente, existe uma crescente investigação quanto à eficácia de intervenções de relaxação e intervenções baseadas no mindfulness ao nível da qualidade de vida e bem-estar dos cuidadores formais. Estes manifestam altos níveis de stress e apresentam um elevado risco de desenvolver síndrome de burnout e sintomas de ansiedade e de depressão. Intervenções centradas em técnicas de relaxação e mindfuness têm demonstrado diversos benefícios ao nível da saúde mental nos cuidadores formais, reduzindo sintomas patológicos e melhorando o seu bem-estar. O presente estudo pretende conhecer os efeitos de uma intervenção psicomotora, mediada pela relaxação, durante 8 semanas nos indicadores de saúde mental (ansiedade, estados depressivos, níveis de stress e de burnout) e fisiológicos do stress (cortisol salivar e alfa amílase salivar) dos cuidadores formais. A amostra final compreendeu 3 estudos de caso. Foram utilizados para avaliação quantitativa a Escala de Ansiedade, Depressão e Stress (EADS-21), o Inventário de Burnout de Maslach (MBI) e a determinação dos níveis de cortisol salivar e de alfa-amílase salivar. Para avaliação qualitativa foi utilizada uma entrevista semiestruturada. Os resultados demonstram a redução dos níveis percebidos de ansiedade, de stress e de exaustão emocional, a manutenção de níveis ótimos de realização pessoal e despersonalização, após a intervenção. Os dados sugerem que a intervenção desenvolvida pode contribuir para a redução de sintomas depressivos e de síndrome de burnout. Os cuidadores reportaram maior consciência dos sintomas físicos e psicológicos associados a cada uma das patologias e a utilização das técnicas aprendidas, para gerir situações de stress no quotidiano e na vida profissional, assim como para melhorar a sua regulação emocional nestas situações; - Effects of a psychomotor intervention mediated by relaxation on formal caregiver's physiological and psychological indicators: case studies
Abstract:
Currently, there is growing research on the effectiveness of relaxation and mindfulness-based interventions in improving the quality of life and well-being of formal caregivers. These caregivers experience high levels of stress and are at significant risk of developing burnout syndrome, as well as symptoms of anxiety and depression. Relaxation and mindfulness interventions have demonstrated several mental health benefits for formal caregivers, reducing pathological symptoms and clinical conditions while improving their well-being. The present study aims to explore the effects of an eight-week psychomotor intervention, mediated by relaxation, on mental health indicators (anxiety, depressive states, stress, and burnout levels) and physiological stress markers (salivary cortisol and salivary alpha-amylase) in formal caregivers. The sample comprised three case studies. Quantitative assessment tools included the Depression, Anxiety and Stress Scale (DASS-21), the Maslach Burnout Inventory (MBI), and the measurement of salivary cortisol and salivary alpha-amylase levels. A semi-structured interview was used for qualitative evaluation. The results suggest that the intervention promoted a reduction in perceived levels of anxiety, stress, and emotional exhaustion, maintained optimal levels of personal accomplishment and depersonalization, and can help prevent depression and burnout syndrome. Caregivers reported becoming more aware of the physical and psychological symptoms associated with each condition and utilized the techniques to better cope with stressful situations in daily life, both professionally and in terms of emotional regulation
Zero Limit for Multi-D Conservation Laws with Nonlinear Diffusion and Dispersion
No full textWe consider a class of nonlinear dissipative-dispersive perturbations of the scalar hyperbolic conservation law and we study the convergence of the approximated solutions to its entropy solution. In particular, we obtain conditions under which the balance between dissipation and dispersion gives rise to the convergence.Partial support by the Grant Agency FCT of Portugal under program PEst-OE/MAT/UI0117/2014
Cultura da alfarrobeira – uma aposta na sustentabilidade agrícola do Alentejo
No full textA alfarrobeira, reconhecida pela sua resistência a condições ambientais adversas e pelo elevado valor económico dos seus frutos, tem potencial para se afirmar como uma cultura estratégica no Alentejo, contribuindo simultaneamente para a diversificação agrícola, para a valorização dos recursos genéticos nacionais e para a promoção de práticas agrícolas mais sustentáveis e resilientes às alterações climáticas
Desenho em Arquitectura
No full textPretende-se neste pequeno livro sintetizar um percurso pedagógico sobre as unidades curriculares de desenho do primeiro ano nos cursos de Arquitectura de duas Universidades, onde tivemos directa influência como docentes e regentes. Temos noção que um tema tão contínuo como o tema do desenho é já de si um desafio de organização e quando abandonamos as
taxonomias disciplinares e entramos na arena pedagógica o desafio quase nos leva a uma astenia generalizada. Por isso temos de nos suportar na experiência e nos resultados, únicos veículos capazes de manifestarem as suas motivações e meios.Art is Underground Publishin
Sustentabilidade na viticultura: um imperativo para Portugal
Full text linkCom a evolução da ciência, foi possível
estabelecer técnicas de biotecnologia e
de biologia molecular que têm vindo a ser
utilizadas em diversos países europeus
no sentido de desenvolver novas castas
resistentes aos principais agentes
patogénicos da vinha. Países como a
Alemanha, a França, a Suíça, e a nossa
vizinha Espanha estabeleceram vários
programas de melhoramento focados
no melhoramento de castas tradicionais
por introdução da informação genética
associada à resistência. E em Portugal
On a Limit of Perturbed Conservation Laws with Diffusion and Non-Positive Dispersion
No full textWe consider a conservation law perturbed by a linear diffusion and a general form of non-positive dispersion. We prove the convergence of the corresponding solution to the entropy weak solution of the hyperbolic conservation law.N/