1,848 research outputs found
Padrões de deslocamento de Cebus nigritus (Cebidae, Mammalia) em mosaico de floresta nativa e plantios de Pinus e Eucalyptus.
Editores técnicos: MarcÃlio José Thomazini, Elenice Fritzsons, PatrÃcia Raquel Silva, Guilherme Schnell e Schuhli, Denise Jeton Cardoso, Luziane Franciscon. EVINCI. Resumos
Occupation time of exclusion processes with conductances
Em publicação em "Journal of statistical physics". ISSN 0022-4715.We obtain the fluctuations for the occupation time of one-dimensional symmetric exclusion processes with speed change, where the transition rates ({\em conductances}) are driven by a general function . The approach does not require sharp bounds on the spectral gap of the system nor the jump rates to be bounded from above or below. We present some examples and for one of them, we observe that the fluctuations of the current are trivial, but the fluctuations of the occupation time are given by a fractional Brownian Motion. This shows that, in general, the fluctuations of the current and of the occupation time are not of same order.CAPESFundação para a Ciência e a Tecnologia (FCT)CNP
Desenvolvimento de marcadores baseados em RGAs associados com QTL de efeito maior para resistência ao mosaico comum em milho.
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Is vigorous-intensity physical activity required for improving bone mass in adolescence? Findings from a Brazilian birth cohort.
UNLABELLED: The association between moderate and vigorous physical activity throughout adolescence and areal bone density (aBMD) at 18 years of age was evaluated. Vigorous-intensity physical activity at 11, 15, and 18 years was associated with aBMD in early adulthood, especially in boys. Cross-sectional analyses showed a positive association between moderate physical activity and aBMD. INTRODUCTION: To evaluate independent associations of moderate and vigorous physical activity (MPA, VPA) across adolescence with areal bone mineral density (aBMD). METHODS: Physical activity (PA) was assessed at 11, 15, and 18 years of age by self-report and at 18 years by accelerometry in the 1993 Pelotas Birth Cohort Study. Time spent in MPA and VPA was determined using metabolic equivalents and specific cutoffs based on raw acceleration. Lumbar spine and femoral neck aBMD were measured by DXA at 18 years. Statistical analyses evaluated the association of MPA and VPA with aBMD, after adjusting for skin color, asset index, current height and age at menarche, and peak strain score (based on ground reaction forces of PA). RESULTS: Lumbar spine and femoral neck aBMD were available for 3947 (49.9% of boys) and 3960 (49.6% of boys) individuals, respectively. Time spent in MPA at 11 and 15 years was not associated with aBMD. VPA at all time points was positively related to both lumbar spine and femoral neck aBMD in boys. Results were consistent for objectively measured VPA. Girls who achieved 75+ minutes/week of VPA in at least two follow-ups showed higher aBMD at 18 years of age. Boys who reached 75+ minutes/week of VPA at all follow-ups had on average 0.117 g/cm2 (95% CI: 0.090; 0.144) higher femoral neck aBMD than those who never achieved this threshold. CONCLUSIONS: Self-reported VPA but not MPA throughout adolescence was associated with aBMD. Recommendation for PA in young people should consider the importance of VPA.Authors also acknowledge the MRC Epidemiology PA Programme for
assisting with analyses and support of activity monitors funding bodies
Medical Research Council and Research Council of Norway
High current–density anodic electrodissolution in flow–injection systems for the determination of aluminium, copper and zinc in non–ferroalloys by flame atomic absorption spectrometry
An automatic procedure with a high current-density anodic electrodissolution
unit (HDAE) is proposed for the determination of
aluminium, copper and zinc in non-ferroalloys by flame atomic
absorption spectrometry, based on the direct solid analysis. It
consists of solenoid valve-based commutation in a flow-injection
system for on-line sample electro-dissolution and calibration with
one multi-element standard, an electrolytic cell equipped with two
electrodes (a silver needle acts as cathode, and sample as anode),
and an intelligent unit. The latter is assembled in a PC-compatible
microcomputer for instrument control, and for data
acquisition and processing. General management of the process is
achieved by use of software written in Pascal. Electrolyte
compositions, flow rates, commutation times, applied current and
electrolysis time were investigated. A 0.5 mol l-1 HN03 solution
was elected as electrolyte and 300 A/cm2 as the continuous current
pulse
Dynamics of spin correlations in the spin-1/2 isotropic XY chain in a transverse field
Dynamic xx spin pair correlation functions for the isotropic spin-1/2 XY
chain are calculated numerically for long open chains in the presence of a
transverse magnetic field at finite temperature. As an application we discuss
the temperature dependence of the spin-spin relaxation time in PrCl_3.Comment: 2 pages, latex, 2 figures, abstract of the paper presented at Ampere
Summer School ``Applications of Magnetic Resonance in Novel Materials''
Nafplion, Greece, 3-9 September, 2000, partially published in J. Phys. A:
Math. Gen. 33, 3063 (2000
Influência do meio nutricional na produção de celulases em fermentação semi-sólida do bagaço de cana-de-açúcar por Aspergillus niger.
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