RESUMO
Deltas and estuaries are formed through periods of marine transgression and regression, which are the continuity of a river and provide key information about its evolution. However, many of the world's deltas are increasingly exposed to the impacts of human activities. While changes affecting the subaerial parts of deltas have been intensively studied, much less is known of their subaqueous parts, the understanding of which is important in gauging overall potential delta vulnerability. This research evaluates the bathymetric changes in the submerged delta of the Turia river (Western Mediterranean, Spain) before and after the extreme flood event of 1957, after which the riverbed was diverted. Three nautical charts were processed (1878, 1988 and 2022), including georeferencing and Digital Elevation Model (DEM) generation. In order to evaluate changes before and after the event, models for 1878-1988 and 1988-2022 were compared and differences were quantified in order to assess erosion and aggradation trends. The results indicate a more aggradated submerged delta in the surroundings of the old river mouth, favored by the high sediment availability since the end of the Little Ice Age (LIA), and the presence of a smaller delta next to its current river mouth to the south of the harbor of Valencia. Bathymetric reconstructions also made it possible to map some incisions in the inner continental shelf as river channels that migrated eastwards when the sea level was lower during MIS 2. Finally, the comparison of bathymetric models also revealed the scarcity of sediments on the current shelf since 1988, which is attributed to anthropogenic action. The successive extensions of the harbor are increasingly distorting the distribution of sediments along the coast and are thus remodeling seabed sediment distribution. Knowing the sedimentation in deltaic systems means better predicting future alterations due to increased anthropization and of the climate change.
RESUMO
The relationship between late-onset gestational diabetes mellitus [GDM] and oxidative stress is not well known, and the importance of the oxidant/antioxidant equilibrium in the clinical evolution and its complications require elucidation. The aim of the study was to evaluate the relationships between maternal levels of markers of oxidative stress in women with late-onset GDM that, potentially, may have considerable clinical implications in the pathogenesis and/or the evolution of GDM. Pregnant women (n = 78; 53 with GDM, 25 controls), between the 24th and 29th week of gestation, were enrolled. Both groups were analysed for demographic data, perinatal and obstetrics outcomes together with the levels of the marker's oxidative stress and antioxidant status. Control versus patient results in the univariate analysis were the following: pre-gestational body mass index [BMI] 23.31 ± 4.2 vs. 27.13 ± 4.6 kg/m(2) (P = 0.001); weeks at delivery 39.2 ± 3.05 vs. 38.9 ± 1.8 (P = 0.09); Caesarean delivery 12.5 vs. 43% (P = 0.004); macrosomia 4 vs. 9.4% (P = 0.6); lipoperoxides [LPO] 2.06 ± 1.00 vs. 3.14 ± 1.55 µmol/mg (P = 0.001); catalase 3.23 ± 1.41 vs. 2.52 ± 1.3 nmol/min/ml (P = 0.03); superoxide dismutase [SOD] 0.11 ± 0.04 vs. 0.08 ± 0.01 U/ml (P = 0.0003); glutathione peroxidase [GPX] 0.03 ± 0.006 vs. 0.025 ± 0.006 nmol/min/ml (P = 0.01); glutathione reductase [GSH] 0.004 ± 0.002 vs. 0.004 ± 0.004 nmol/min/ml (P = 0.9)]; and glutathione transferase [GST] 0.0025 ± 0.0012 vs. 0.0027 ± 0.00017 nmol/min/ml (P = 0.7). Multivariate analysis showed catalase might have a protective effect against GDM development and LPO seems to be a risk factor for the disease. These data suggest an increase in oxidative stress and a decrease in antioxidative defence in women with late-onset GDM and, as such, may have considerable clinical implications in the pathogenesis and/or the course of the pregnancy in these patients.
