238 research outputs found

    Composições de susbstratos e ambientes de enraizamento na estaquia de Ilex paraguariensis A. St.-Hil.

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    Devido à carência de informações a respeito da propagação vegetativa de erva-mate, conduziu-se um experimento com o objetivo de avaliar o ambiente de enraizamento e composições de substrato na sobrevivência, enraizamento e vigor de estacas de Ilex paraguariensis de plantas de 12 anos de idade. Testou-se o efeito de três clones (A32, A34 e A36), seis substratos (S1 - substrato para enraizamento à base de casca de pinus; S2 - substrato para enraizamento à base de casca de pinus e vermiculita; S3 - casca de arroz carbonizada + vermiculita fina + substrato para enraizamento à base de casca de pinus e vermiculita (1:1:1 v/v); S4 - casca de arroz carbonizada + substrato para enraizamento à base de casca de pinus e vermiculita (1:1 v/v); S5 - casca de arroz carbonizada + vermiculita fina (1:1 v/v); S6 - fibra de coco) e dois ambientes de enraizamento (casa de vegetação automatizada e simples). Embora não tenham ocorrido grandes variações entre os ambientes testados, o enraizamento das estacas mostrou-se baixo. O uso da mistura de casca de arroz carbonizada + substrato para enraizamento à base de casca de pinus e vermiculita na proporção 1:1 (v/v) é aconselhado para estaquia de erva-mate

    Perturbed Spherically Symmetric Dust Solution of the Field Equations in Observational Coordinates with Cosmological Data Functions

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    Using the framework for solving the spherically symmetric field equations in observational coordinates given in Araujo and Stoeger (1999), their formulation and solution in the perturbed FLRW sperically symmetric case with observational data representing galaxy redshifts, number counts and observer area distances, both as functions of redshift on our past light cone, are presented. The importance of the central conditions, those which must hold on our world line C, is emphasized. In detailing the solution for these perturbations, we discuss the gauge problem and its resolution in this context, as well as how errors and gaps in the data are propagated together with the genuine perturbations. This will provide guidance for solving, and interpreting the solutions of the more complicated general perturbation problem with observational data on our past light cone.Comment: Latex 23 pages, no figures, submitted to Astrophysical Journa

    Circadian rhythm of activity levels: influence of chronotype.

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    Aim: The aim of this study is to investigate, by an actigraph monitoring, the differences in the circadian rhythm of activity level in relation to the chronotype for the sake of studying its influence on physical performance. Morning-type (M-type), Evening-type (E-types) and Neither-type (N-type) are the classified chronotypes; several studies showed the differences between M-types and E-types in the circadian rhythm of different physiological variables: M-types use to wake up and go to bed early and to have their best performances in the first part of the day, otherwise E-types go to bed and wake up late and they have the peak performances in the evening (Vitale et al., 2013). Method: The morningness\u2013eveningness questionnaire (MEQ) was administered to 502 college students to determine their chronotypes. Fifty subjects (16 M-types, 15 N-types and 19 E-types) were recruited to undergo a 7-days monitoring period with an actigraph (Actiwacth actometers, CNT, Cambridge, UK) to evaluate their sleep parameters and the circadian rhythm of their activity levels. To evaluate the circadian rhythmicity of activity levels we used the single cosinor method (Halberg et al., 1977) and we define three parameters characteristic of each statistically significant rhythm: M, MESOR (Midline Estimating Statistic Of Rhythm); A, Amplitude; \u3d5, acrophase. The population circadian characteristics were determined and then compared using the Hotelling test. Results: Rhythmometric analysis, with the single cosinor method, on the activity data collected by the actigraph revealed a statistically significant circadian rhythm (p<0.001) for all the 50 subjects. The population mean cosinors were calculated grouping the different chronotypes: M-types, E-types and N-types (p<0.001). No statistical differences about MESOR were showed for all group combinations (p>0.05) but a significant difference (p<0.05) was observed if considering the Amplitude-Acrophase test for all groups combinations, in particular M-types had an early acrophase of the circadian rhythm of the activity levels, at 14.37, while E-types showed an acrophase with more than 2 hours late, at 17.04 (p<0.001); the group of Ntypes showed an intermediate acrophase, at 15.45, between morning-types and evening-types. Conclusion: We can assume that there is a clear difference between \u201clarks\u201d and \u201cowls\u201d and this results are in line with other studies that showed the biological differences among chronotypes. We can conclude that M-types are more active in the early afternoon and that E-types have the peak of their activity in the late afternoon. Further studies are needed to better understand if and how the chronotype influence a physical performance. References 1. Halberg F., Carandente F., Cornelissen G., Katinas G.S. (1977). Glossary of chronobiology. Chronobiologia 4 (Suppl. 1):1-189. 2. Vitale J.A., Calogiuri G., Weydahl A. (2013). Percept. Mot. Skills. 116(3):1020-1028

    Anthropometric indices of adiposity and fasting glucose metabolism in breast cancer survivors: effects of aerobic physical activity

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    Adiposity and hypersinsulinemia are factors involved in cancer mortality including BC (1). Physical activity (PA) has the potential to counterbalance these risk factors. In fact, PA has been shown to produce beneficial effects on adiposity and glucose metabolism (2). We thus designed a randomized controlled trial to test the effect of an aerobic PA program on anthropometric indices of adiposity and fasting glucose metabolism in BC women included in a dietary intervention trial for prevention of BC recurrences. 42 BC women, aged 35-70 years, were randomized into an intervention (IG=19) and control group (CG=23). The IG had to participate in a 3-month active PA program that included two sessions of one-hour brisk walking per week. At baseline and after 3-month, all women were requested to undergo an anthropometric visit and to collect a blood sample for determination of fasting insulin and glucose levels. At the end of the 3-month PA a significant reduction in waist circumference (p&lt;0.05) and percentage fat mass (p&lt;0.01) were observed in IG, but not in CG. In addition, only IG increased significantly their Metabolic Equivalent of Task (METs) (p&lt;0.05). Although fasting glucose and insulin levels don\u2019t show any significant change in either group, it is nevertheless encouraging that the two groups displayed an opposite trend as far as the changes in fasting insulin were concerned: fasting insulin shows a mean reduction (-0.9 \uf06dU//ml) in the IG group and a mean increment in the CG (+0.7 \uf06dU/ml). The results suggest that a standardized PA program in BC survivors reduces anthropometric indices of adiposity and may prove useful in preventing the development of hyperinsulinemic levels. References 1. Mann et al. (2014) Changes in insulin sensitivity in response to different modalities of exercise: a review of the evidence. Diabetes Metab Res Rev. 30(4): 257-268. 2. Pisani (2008) Hyper-insulinaemia and cancer, meta-analyses of epidemiological studies. Arch Physiol Biochem 114(1): 63\u201370

    Actigraphy-based activity levels and anthropometric measurements in breast cancer survivors: effects of aerobic physical activity

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    The research investments for the identification of modifiable factors associated with BC recurrences is increasing. Adiposity and other anthropometric indices have been acknowledged as factors involved in BC recurrences and mortality (1). Physical activity (PA) has the potential to counterbalance all of these risk factors (2). We designed a randomized controlled trial to test the effect of an aerobic PA program on anthropometric indices of adiposity and circadian rhythm activity level, evaluated by actigraphy, in BC women included in a dietary intervention trial for prevention of BC recurrences. 40 BC women, aged 35-70 years, were randomized into an intervention (IG=19) and a control group (CG=21). The IG participated in a 3-month active PA program that included two sessions of one-hour brisk walking per week. At baseline and after 3 months, both IG and CG were evaluated for the following parameters: height, weight, BMI, waist circumferences, % fat mass, % lean mass; energy expenditure and motion level (Total Energy Expenditure-TEE, number of steps, PA level, Metabolic Equivalents-METs) using a SenseWear Pro 3 Armband; and activity level circadian rhythm using the Actigraph Actiwatch. At the end of the 3-month PA program, IG showed a significant reduction in fat mass % while CG improved weight and BMI. The population mean cosinor applied to IG and CG at PRE and POST revealed the presence of a significant circadian rhythm in two groups (

    Phenotypic characterization of cassava ethno-varieties in the state of Mato Grosso, Brazil.

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    Brazil is the fourth largest producer of cassava in the world. In the state of Mato Grosso more than 90% of family farmers grow cassava; therefore, studies that evaluate the genetic resources of this species present in the fields of these farmers can be considered essential. The objective of this study was to evaluate the genetic variability among ethnovarieties of cassava grown in five regions of the state of Mato Grosso, at a phenotypic level using morphoagronomic and molecular characteristics. Forty-five ethnovarieties of cassava were evaluated using 45 morphoagronomic descriptors, 36 qualitative descriptors and nine quantitative descriptors, in addition to 15 microsatellite loci. The data were analyzed with the help of the Past and Genes programs. The descriptors of qualitative nature revealed the existence of morphological divergence, with 97.35% polymorphism and the formation of five genetic groups using the UPGMA method. Forty-four ethno-varieties had more than one desirable root characteristic from an agronomic point of view. Among all the varieties, the Amarela I ethno-variety had the most of these characteristics. With the quantitative variables obtained using the UPGMA method, it was possible to form seven distinct groups, which revealed the Branca Comum and Paraguaia ethno-varieties to be the most dissimilar. The characteristic that most contributed to the distinction of the groups was that of root length (30%). The 15 microsatellite loci amplified 109 alleles, and mean heterozygosity observed was higher than the expected heterozygosity. The UPGMA grouping revealed the formation of four distinct groups, and it was possible to verify duplicity of the Mandioca Batatinha and Pramuquem ethnovarities. By using joint analysis of the data, five genetic groups were observed, without duplicity of material; groups III, IV and V were isolated individuals. Between qualitative and quantitative variables, there was a significant correlation of 31% and between qualitative and molecular data the correlation was 12.4%. The collection of ethnovarieties grown in the fields of family farmers in the state of Mato Grosso present genetic divergence at the phenotypic level, based on morphoagronomic and molecular characteristics, and these ethno-varieties have characteristics of interest for genetic improvement and improved marketability
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