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| The existence of a circadian rhythm of atrial natriuretic peptide (ANP) in humans is controversial. We studied the plasma ANP response to isotonic blood volume expansion in the morning and in the afternoon and its relationship with adrenocorticotropic hormone (ACTH)-cortisol diurnal variation in seven normal subjects. Basal plasma ANP level was similar in the morning (19.6 ± 2.4 pg/ml) and in the afternoon (21.8 ± 4.8 pg/ml). The ANP peak obtained with saline infusion (0.9% NaCl, 12 ml/kg) in the morning (49.4 ± 8 pg/ml) did not differ from that obtained in the afternoon (60.3 ± 10.1 pg/ml). There was no correlation between the individual mean cortisol and ACTH levels and the ANP peak obtained with saline infusion. These data indicate no diurnal variation... |
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Palavras-chave: ANP; Diurnal variation; ACTH; Cortisol. |
| Ano: 1997 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997000500008 |
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| Blanchard, Gerard; Simon Bouhet, B; Guarini, J. |
| The short-term variability of intertidal microphytobenthic biomass was characterized by analysing a 30-day time series encompassing two spring-neap tide cycles. Chlorophyll-a concentration was measured every day at the beginning and at the end of every diurnal exposure periods. Microalgal biomass exhibited predictible net increases during diurnal exposures due to a positive production-loss balance. In addition, our data series shows that after an environmental disturbance, even though biomass decreased strongly, it converged quickly back to its initial steady-state oscillation pattern. This study supports some fundamental properties of the dynamics of microphytobenthic biomass, as previously predicted in our mathematical model of primary production. |
| Tipo: Text |
Palavras-chave: Diurnal variation; Chlorophyll concentration; Microphytobenthic biomass. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/2002/publication-599.pdf |
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| Silva,Tâmara de Almeida e; Neumann-Leitão,Sigrid; Schwamborn,Ralf; Gusmão,Lúcia Maria de Oliveira; Nascimento-Vieira,Dilma Aguiar do. |
| Studies were carried out to assess the macrozooplankton small-scale temporal and spatial variability at three stations in three hours intervals, during 24 hours in July 1996 (rainy season) and December 1996 (dry season). A plankton net 300µm mesh size was hauled at surface during three minutes. Water samples for salinity, temperature, dissolved oxygen and pH were taken simultaneously with the zooplankton samples. Sixty-five macrozooplankton taxa were registered. Copepoda constituted the most common taxon and comprised 58% of the total zooplankton counts. Brachyuran zoeae, cirripedian larvae, Larvacea (Oikopleura dioica Fol, 1872), and Gastropoda veligers were abundant at some tidal cycles, mainly during the night. Species diversity average was 2.0... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Diurnal variation; Estuary; Planktonic fauna; Tidal variation. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81752003000300012 |
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