1,952 research outputs found

    Emergy analysis of a silvo-pastoral system, a case study in southern Portugal

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    The Mediterranean silvo-pastoral system known as Montado, in Portugal, is a complex land use system composed of an open tree stratum in various densities and an herbaceous layer, used for livestock grazing. Livestock also profit from the acorns, and the grazing contributes to avoid shrub encroachment. In the last 20 years, subsidies from the European Union have greatly promoted cattle rearing in this system and the introduction of heavy breeds, at the expense of sheep, goats or the native cattle breeds. The balance of the traditional system is thus threatened, and a precise assessment of the balance between the different components of the system, therefore is highly needed. The goal of this study was to gain a better understanding of a Montado farm system with cattle rearing as the major economic activity by applying the emergy evaluation method to calculate indices of yield, investment, environmental loading and sustainability. By integrating different ecosystem components, the emergy evaluation method allows a comprehensive evaluation of this complex and multifunctional system at the scale of an individual farm. This method provides a set of indices that can help us understand the system and design management strategies that maximize emergy flow in the farm. In this paper, we apply the emergy evaluation method to a Montado farm with cattle rearing, as a way to gain a better understanding of this system at the farm scale. The value for the transformity of veal (2.66E+06 sej J−1) is slightly higher, when compared to other systems producing protein. That means that the investment of nature and man in this product was higher and it requires a premium price on the market. The renewability for Holm Oaks Farm (49 %), lower than for other similar systems, supports the assumption that this is a farm in which, comparing with others, the number of purchased inputs in relation to renewable inputs provided by nature, is higher. The Emergy Investment Ratio is 0.91 for cattle rearing compared to a value of 0.49 for cork and 0.43 for firewood harvesting, making it clear that cattle rearing is a more labor demanding activity comparing with extractive activities as cork and firewood harvesting

    Body composition comparison between gender in institutionalized elderly

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    Este estudo teve como objetivo averiguar sobre a existência de diferenças entre sexos, da composição corporal de idosos institucionalizados.The purpose of this Study was to compare the body composition differences between gender in institutionalized elderly.info:eu-repo/semantics/publishedVersio

    Do the strength levels predict the motor coordination in young basketball players?

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    O objetivo deste estudo foi averiguar sobre a existência de relação entre os níveis de força e a coordenação motora em basquetebolistas pertencentes ao escalão de sub-18.The aim of this study was to analyse the relation between the strength levels and motor coordination in young basketball players.info:eu-repo/semantics/publishedVersio

    Evolution in swimming "science" research

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    Swimming seems to be one of the sports more studied . More than one decade ago, Clarys (1996) made an content analysis of the research about swimming. However, in these last 13 years several developments happened in the aquatic activities

    Evolution on Swimming Science Research: content analysis of the “Biomechanics and Medicine in Swimming” Proceedings Books from 1971 to 2006

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    Swimming seems to be one of the sports more studied . More than one decade ago, Clarys (1996) made an content analysis of the research about swimming. However, in these last 13 years several developments happened in the aquatic activities

    Imbalance of naive and memory T lymphocytes with sustained high cellular activation during the first year of life from uninfected children born to HIV-1-infected mothers on HAART

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    The immune consequences of in utero HIV exposure to uninfected children whose mothers were submitted to highly active antiretroviral therapy (HAART) during gestation are not well defined. We evaluated 45 HIV-exposed uninfected (ENI) neonates and 45 healthy unexposed control (CT) neonates. All HIV-infected mothers received HAART during pregnancy, and the viral load at delivery was <50 copies/mL for 56.8%. Twenty-three ENI neonates were further evaluated after 12 months and compared to 23 unexposed healthy age-matched infants. Immunophenotyping was performed by flow cytometry in cord and peripheral blood. Cord blood lymphocyte numbers did not differ between groups. However, ENI neonates had a lower percentage of naive T cells than CT neonates (CD4+, 76.6 vs 83.1%, P < 0.001; CD8+, 70.9 vs 79.6%, P = 0.003) and higher percentages of central memory T cells than CT neonates (CD4+, 13.9 vs 8.7%, P < 0.001; CD8+, 8.6 vs 4.8%, P = 0.001). CD38 mean fluorescence intensity of T cells was higher in ENI neonates (CD4+, 62.2 vs 52.1, P = 0.007; CD8+, 47.7 vs 35.3, P < 0.001). At 12 months, ENI infants still had higher mean fluorescence intensity of CD38 on T cells (CD4+, 34.2 vs 23.3, P < 0.001; CD8+, 26.8 vs 19.4, P = 0.035). Despite effective maternal virologic control at delivery, HIV-exposed uninfected children were born with lower levels of naive T cells. Immune activation was present at birth and remained until at least 12 months of age, suggesting that in utero exposure to HIV causes subtle immune abnormalities.FAPESPCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

    Influence of hormonal replacement therapy in lipid peroxidation levels of postmenopausal women with different cardiovascular capacity

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    It has been suggested that exercise has a positive impact on the prevention and progression of cardiovascular disease (CVD). One of the main mechanisms is through the modification of lipoprotein levels and the risk of its oxidation, especially LDL lipoproteins. After menopause, women experience an increased incidence of cardiovascular disease. In contrast, women receiving hormonal replacement therapy (HRT) seem to be protected. The aim of this study was to infer how HRT affect lipid peroxidation levels in postmenopausal women with different levels of aerobic fitness. Design & Method: Sixty four women participate in this study, 32 of them receive HRT (group with HRT – GWHRT) (average age¼55.9 years, average weight¼ 66.9 kg and average high¼156.0 cm) and the remained 32 women didn’t receive HRT (group without HRT – GWOHRT) (average age¼61.0 years, average weight¼ 67.6 kg and average high¼154.3 cm). Total cholesterol (mg dL71), HDL-cholesterol (mg dL71), LDL-cholesterol (mg dL71) and triglycerides levels (mg dL71) have been analyzed in serum obtained from a blood sample collected after 8 hours of fasting, and measured in Dr. Lange LP20 according to the specific manufacturer instructions. Serum MDA concentration (ng L71) was determined by spectrophotometric method. Aerobic capacity (VO2max ml kg71 min71) was assessed according to an adaptation of Bruce protocol. Differences between groups were tested through Student t-test. A Spearman correlation was performed in order to test variables associations. Significance level was established at 5%.Results: Our results have found differences between groups in age (t¼3.018; p50.01), in VO2max (t¼73.774; p50.01) and in serum MDA concentration (t¼6.750; p50.01). The GWHRT were younger, had a higher VO2max (31.38 for GWHRT and 26.19 for GWOHRT), and had lower levels of serum MDA concentration (0.29 for GWHRT and 0.73 for GWOHRT) comparatively with those women from the GWOHRT. However, our results failed to find any differences between groups regarding serum triglycerides, total cholesterol, HDL-cholesterol, LDL-cholesterol or BMI. In this study, serum MDA concentration didn’t correlate with higher levels of lipid profile, as we might have expected, but correlate inversely with HRT (r¼7.726, p¼.00) and with VO2max (r¼7.287, p¼.02). Conclusion: Our results suggest that HRT should exert an antioxidant protective effect against lipid peroxidation, as well as exercise perhaps through the stimulation of antioxidant capacity

    Experimental feasibility of measuring the gravitational redshift of light using dispersion in optical fibers

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    This paper describes a new class of experiments that use dispersion in optical fibers to convert the gravitational frequency shift of light into a measurable phase shift or time delay. Two conceptual models are explored. In the first model, long counter-propagating pulses are used in a vertical fiber optic Sagnac interferometer. The second model uses optical solitons in vertically separated fiber optic storage rings. We discuss the feasibility of using such an instrument to make a high precision measurement of the gravitational frequency shift of light.Comment: 11 pages, 12 figure

    Analytical results for coupled map lattices with long-range interactions

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    We obtain exact analytical results for lattices of maps with couplings that decay with distance as rαr^{-\alpha}. We analyze the effect of the coupling range on the system dynamics through the Lyapunov spectrum. For lattices whose elements are piecewise linear maps, we get an algebraic expression for the Lyapunov spectrum. When the local dynamics is given by a nonlinear map, the Lyapunov spectrum for a completely synchronized state is analytically obtained. The critical lines characterizing the synchronization transition are determined from the expression for the largest transversal Lyapunov exponent. In particular, it is shown that in the thermodynamical limit, such transition is only possible for sufficiently long-range interactions, namely, for αalphac<d\alpha\le alpha_c<d, where dd is the lattice dimension.Comment: 4 pages, 2 figures, corrections included. Phys. Rev. E 68, 045202(R) (2003); correction in pres

    Rheological behavior of thermoreversible k-carrageenan/nanosilica gels

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    The rheological behavior of silica/κ-carrageenan nanocomposites has been investigated as a function of silica particle size and load. The addition of silica nanoparticles was observed to invariably impair the gelation process, as viewed by the reduction of gel strength and decrease of gelation and melting temperatures. This weakening effect is seen, for the lowest particle size, to become slightly more marked as silica concentration (or load) is increased and at the lowest load as particle size is increased. These results suggest that, under these conditions, the particles act as physical barriers to polysaccharide chain aggregation and, hence, gelation. However, for larger particle sizes and higher loads, gel strength does not weaken with size or concentration but, rather, becomes relatively stronger for intermediate particles sizes, or remains unchanged for the largest particles, as a function of load. This indicates that larger particles in higher number do not seem to increasingly disrupt the gel, as expected, but rather promote the formation of stable gel network of intermediate strength. The possibility of this being caused by the larger negative surface charge found for the larger particles is discussed. This may impede further approximation of neighboring particles thus leaving enough inter-particle space for gel formation, taking advantage of a high local polysaccharide concentration due to the higher total space occupied by large particles at higher loads.FCT - PTDC/QUI/67712/2006FEDE
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