962 research outputs found

    Antihyperlipemic and antihypertensive effects of Spirulina maxima in an open sample of mexican population: a preliminary report

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    <p>Abstract</p> <p>Background</p> <p><it>Spirulina maxima </it>is a filamentous cyanobacterium used as food supplement because of its high nutrient contents. It has been experimentally proven, <it>in vivo </it>and <it>in vitro </it>that posses several pharmacological properties. The purpose of this study was to evaluate the effects of <it>Spirulina maxima </it>orally supplied (4.5 g/day, for 6 weeks) to a sample of 36 subjects (16 men and 20 women, with ages between 18–65 years) on serum lipids, glucose, aminotransferases and on blood pressure. The volunteers did not modify their dietary habits or lifestyle during the whole experimental period. From each subject, a sample of blood was drawn in fasting state of 12 hours to determi the plasma concentrations of glucose, triacylglycerols (TAG), total cholesterol (TC), cholesterol associated to high density lipoprotein (HDL-C) and aspartate aminotransferase (AST). Anthropometric measurements including systolic (SYST-P) and diastolic (DIAST-P) blood pressure, height, weight and Body Mass Index (BMI) were also recorded.</p> <p>Results</p> <p>Comparing initial and final data, the results showed that there were no significant changes in the values of glucose and AST, but significant differences in TAG, TC, and HDL-C, were observed: TAG 233.7 ± 177.8 vs. 167.7 ± 100.7 mg/dL (p < 0.001), TC 181.7 ± 37.5 vs. 163.5 ± 34.4 mg/dL (p < 0.001), C-HDL 43.5 ± 14.4 vs. 50 ± 18.8 mg/dL (p < 0.01). The univariated analysis showed that the changes in the HDL-C and TC concentrations were dependent on TAG concentration (p = 0.247 and p = 0.108, respectively); nevertheless the calculated values for cholesterol associated to low density lipoprotein (LDL-C) were significantly reduced by the <it>Spirulina maxima </it>treatment but independently of the TAG changes. In addition, significant differences were found comparing initial and final SYST-P and DIAST-P blood pressure in both male and female: SYST-P male 121 ± 9 vs. 111 ± 8 mm Hg (p < 0.01), DIAST-P male 85 ± 6.5 vs. 77 ± 9 mm Hg (p < 0.01); SYST-P female 120 ± 9.5 vs. 109 ± 11 mm Hg (p < 0.002), DIAST-P female 85 ± 11 vs. 79 ± 7.5 mm Hg (p < 0.03).</p> <p>Conclusion</p> <p>The <it>Spirulina maxima </it>showed a hypolipemic effect, especially on the TAG and the LDL-C concentrations but indirectly on TC and HDL-C values. It also reduces systolic and diastolic blood pressure.</p

    Splash control of drop impacts with geometric targets

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    Drop impacts on solid and liquid surfaces exhibit complex dynamics due to the competition of inertial, viscous, and capillary forces. After impact, a liquid lamella develops and expands radially, and under certain conditions, the outer rim breaks up into an irregular arrangement of filaments and secondary droplets. We show experimentally that the lamella expansion and subsequent break up of the outer rim can be controlled by length scales that are of comparable dimension to the impacting drop diameter. Under identical impact parameters, ie. fluid properties and impact velocity, we observe unique splashing dynamics by varying the target cross-sectional geometry. These behaviors include: (i) geometrically-shaped lamellae and (ii) a transition in splashing stability, from regular to irregular splashing. We propose that regular splashes are controlled by the azimuthal perturbations imposed by the target cross-sectional geometry and that irregular splashes are governed by the fastest-growing unstable Plateau-Rayleigh mode

    A história e filosofia da ciência na pesquisa em ensino de ciências no Brasil : uma análise institucional

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    Desde a segunda metade do século XX uma área de pesquisa em Educação teve um desenvolvimento singular no mundo: Science Education. No Brasil, a Pesquisa em Educação em Ciências (PEC) começou a ser realizada de forma sistemática aproximadamente meio século atrás, sua expansão foi garantida pela implantação de cursos de pós-graduação, eventos e publicações especializadas. Neste trabalho, analisamos o desenvolvimento da área e as contribuições da História e Filosofia da Ciência (HFC) no processo: usamos a teoria de Kaës, sobre o desenvolvimento de Grupos e Instituições para desvelar os aspectos implícitos referentes aos laços partilhados pelos membros da Instituição. Utilizamos dados das memórias pessoais dos autores; resultados de pesquisas e literatura da área; e entrevistas com onze pesquisadores que trabalham na interface entre HFC e PEC

    Dynamic Control of a Novel Planar Cable-Driven Parallel Robot with a Large Wrench Feasible Workspace

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    Cable-Driven Parallel Robots (CDPRs) are special manipulators where rigid links are replaced with cables. The use of cables offers several advantages over the conventional rigid manipulators, one of the most interesting being their ability to cover large workspaces since cables are easily winded. However, this workspace coverage has its limitations due to the maximum permissible cable tensions, i.e., tension limitations cause a decrease in the Wrench Feasible Workspace (WFW) of these robots. To solve this issue, a novel design based in the addition of passive carriages to the robot frame of three degrees-of-freedom (3DOF) fully-constrained CDPRs is used. The novelty of the design allows reducing the variation in the cable directions and forces increasing the robot WFW; nevertheless, it presents a low stiffness along the x direction. This paper presents the dynamic model of the novel proposal together with a new dynamic control technique, which rejects the vibrations caused by the stiffness loss while ensuring an accurate trajectory tracking. The simulation results show that the controlled system presents a larger WFW than the conventional scheme of the CDPR, maintaining a good performance in the trajectory tracking of the end-effector. The novel proposal presented here can be applied in multiple planar applications

    Quantifying the relative contribution of ante- and post-mortem factors to the variability in beef texture

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    This study aims to investigate the relative contribution of ante- and post-mortem factors to the final quality of beef. In all, 112 steers (four breed-crosses) were arranged in a 2 3 2 3 2 factorial experimental including production system, growth implant and b-adrenergic agonist strategies. Carcasses were suspended by the Achilles tendon or the aitch bone and meat was aged for 2/6/13/21/27 days (longissimus muscle) or 2/27 days (semimembranosus muscle). Meat quality traits related to beef texture were measured. Statistical analyses were developed including ante- and post-mortem factors and their relative contribution to the variability observed for each measured trait was calculated. The main factor responsible for the variability in sarcomere length was the suspension method (91.1%), which also influenced drip-loss (44.3%). Increasing the percentage of British breeds increased (P , 0.05) the intramuscular fat content in longissimus muscle, but only when implants were not used. Thus, the breed-cross, implant strategy and their interaction were responsible for .58% of the variability in this trait. The variability in instrumental and sensory tenderness was mainly affected by post-mortem factors (carcass suspension, ageing time and their interaction), explaining generally , 70% of the variability in these traits. Breed-cross was the second most important effect ( ,15%) when carcass suspension was not considered in the model, but still ageing time was responsible for a much larger proportion of the variability in tenderness (.45%). In conclusion, post-mortem handling of the carcasses may be much more effective in controlling beef tenderness than pre-mortem strategies

    Electromagnetic emission from magnetite plate cracking under seismic processes

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    International audienceElectromagnetic emission generated by cracking of a magnetite plate is theoretically investigated. The non-stationary mechanical stresses, produced by moving the tip of a crack and a wave of mechanical unloading in the plate are considered as the sources of the radiation. It is demonstrated that the radiation is produced by the appearance of a non-stationary magnetic moment in the plate

    Methods of application and dosages of insecticides for Aphis gossypii (Glover) (Hemiptera: Aphididae) in the yellow melon

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    [PT] - Para aperfeiçoar o manejo fitossanitário de pragas na cultura do melão (Cucumis melo L.), objetivou-se avaliar os efeitos de formas de aplicação e doses de inseticidas sobre a eficiência de controle químico do pulgão A. gossypii. O experimento foi realizado em 2010, na cidade de Fortaleza, Ceará, com melão amarelo cultivado em condições de campo. O delineamento experimental foi em blocos ao acaso, arranjo fatorial 2 x 4, com quatro repetições e parcelas de seis plantas. Os tratamentos foram duas formas de aplicação (pulverização costal manual e insetigação por gotejamento) e quatro doses de inseticida (0; 50; 100; 200% da dose recomendada pelo fabricante). Os inseticidas acefato e tiametoxam, testados separadamente, foram aplicados em manejo de rotação de grupos químicos. A eficiência de controle foi avaliada sete dias após o uso de cada inseticida. O acefato não apresentou diferença significativa entre as formas de aplicação, atingindo eficiências de controle de 88,95 e 84,09% com 100 e 200% da dose recomendada, respectivamente. O tiametoxam não diferiu significativamente quanto às formas de aplicação e doses testadas, apresentando eficiência de 100% em todos os tratamentos. Atualmente, no Brasil, a utilização de acefato no melão está limitada à aplicação mecanizada devido ao risco de contaminação. Diante dessa limitação, o controle do pulgão em meloeiro amarelo pode ser realizado via insetigação por gotejo ou pulverização costal manual, devendo-se empregar, preferencialmente, 100% da dose recomendada de tiametoxam.[EN] In order to perfect the phytosanitary management of pests in the melon crop (Cucumis melo L.), the aim here was to evaluate the effects of different methods of application and dosages of insecticides on the effectiveness of chemical control of the aphid A. gossypii. The experiment was carried out in 2010, in Fortaleza, in the state of Ceara, Brazil, with yellow melon grown under field conditions. The experimental design was of randomised blocks in a 2 x 4 factorial arrangement, with four replications and lots of six plants. Treatments consisted of two methods of application (manual backpack spray and drip insectigation) and four dosages of insecticide (0, 50, 100 and 200% of the dosage recommended by the manufacturer). The insecticides acephate and thiamethoxam, tested separately, were applied in a rotating management of chemical groups. Efficiency of the control was evaluated seven days after the use of each insecticide. The acephate showed no significant difference between the forms of application, reaching control efficiencies of 88.95 and 84.09% with 100 and 200% of the recommended dose respectively. The thiamethoxam did not differ significantly for the application methods and dosages under test, giving 100% efficiency in all treatments. Currently in Brazil the use of acephate in the melon is limited to mechanised application due to the risk of contamination. Because of this limitation, the control of aphids in yellow melon can be carried out via drip insectigation or backsack spray, with preferably 100% of the recommended dose of thiamethoxam.Do Bomfim, G.; Moreira De Azevedo, B.; Viana, TVA.; Manzano Juarez, J.; Vasconcelos, DV. (2015). Formas de aplicação e doses de inseticidas sobre Aphis gossypii (Glover) (Hemiptera: Aphididae) em melão amarelo. Revista Ciencia Agronomica. 46(3):488-496. doi:10.5935/1806-6690.20150030S48849646

    Confirmation of the Luminous Blue Variable status of MWC 930

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    We present spectroscopic and photometric observations of the emission-line star MWC 930 (V446 Sct) during its long-term optical brightening in 2006--2013. Based on our earlier data we suggested that the object has features found in Luminous Blue Variables (LBV), such as a high luminosity (~3 10^5 Lsun, a low wind terminal velocity (~ 140 km/s), and a tendency to show strong brightness variations (~1 mag over 20 years). For the last ~7 years it has been exhibiting a continuous optical and near-IR brightening along with a change of the emission-line spectrum appearance and cooling of the star's photosphere. We present the object's VV--band light curve, analyze the spectral variations, and compare the observed properties with those of other recognized Galactic LBVs, such as AG Car and HR Car. Overall we conclude the MWC 930 is a bona fide Galactic LBV that is currently in the middle of an S Dor cycle.Comment: 12 pages, 7 figure

    The layer by layer selective laser synthesis of ruby

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    In the work, features of the layer-by-layer selective laser synthesis (SLS) of ruby from an Al2O3-Cr2O3 mixture are considered depending on the irradiation power, the laser beam traverse speed, the height and amount of the backfill of powder layers. It has been established that, under irradiation, a track consisting of polycrystalline textured ruby forms. The morphology of the surface of the track and its crystalline structure are determined by the irradiation conditions
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