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[1] Nearly continuous data collected using novel methods are utilized to advance the understanding of turbulence and suspended particulate matter (SPM) dynamics under strong tidal flow conditions. Key instrumentation includes a single acoustic current profiler that provides nearly continuous, concurrent turbulence and SPM information with respect to depth near the seafloor and within the water column. Observations show a lag of about 1 hour in turbulence production between the bottom and 12 meters above the bottom (mab), and of about 1.5 hours for SPM. Estimates of eddy viscosity show values ranging between 10 À3 and 10 À2 m 2 s À1, with an almost constant mean value of 3.5 Â 10 À3 m 2 s À1 within the bottom 7 meters. The present observations and a previously reported theory show good agreement in both amplitude and phase for SPM and turbulence, when values of eddy viscosity ranging between 3.5 Â 10 À3 (mean) and 10 À2 (maximum) are used. Our data set is valuable for evaluating, developing, and improving turbulence and SPM numerical models.

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Background The International Study of Asthma and Allergies in Childhood (ISAAC) showed a wide variability in prevalence and severity of allergic rhinitis (AR) and rhinoconjunctivitis (ARC), in addition to other atopic diseases (Asher et al, 2006). 1 The Global Asthma Network (GAN) has continued to study these conditions. Objective To estimate the prevalence of AR and ARC in children and adolescents in Mexico and to assess their association with different risk factors. Methods GAN Phase I is a cross-sectional, multicentre survey carried out in 15 centres corresponding to 14 Mexican cities throughout 2016–2019 using the validated Spanish language version of the GAN Phase I questionnaires. The questionnaires were completed by 35 780 parents of 6–7 year old primary school pupils (children) and by 41 399 adolescents, 13–14 years old. Results The current and cumulative prevalence of AR was higher in the adolescents (26.2–37.5%, respectively) in comparison to the children (17.9–24.9%, respectively), especially in female participants. This tendency was also observed in the current prevalence of ARC, where 15.1% of female adolescents reported nasal symptoms accompanied with itchy-watery eyes in the past year. The most important risk factors for AR and ARC were the presence of wheezing in the past 12 months, wheezing in the first year of life, the previous diagnosis of asthma and eczema symptoms. Furthermore, allergic symptoms had a negative tendency concerning altitude. Conclusion This is the largest AR epidemiological study ever conducted in Mexico. It shows an increase in AR prevalence, as well as significant associations with modifiable risk factors, which could help to establish recommendations to reduce the burden of this condition.

Sediment cores from the Colorado River (CR) remnant delta were used to assess the changing sedimentation and pollutant deposition processes in response to extensive human manipulation of the river. The cores are formed of alternating layers of clays and silts, with isolated sandy horizons. The clayey units are interpreted as periods of flood flows into this low gradient and meandering estuary after dam construction in the United States. The geochemistry of these sediments is particular because of the association of MnO with CaO rather than with the Fe(2)O(3)-rich clays. Past pollution of the CR delta by As, and probably also Pb and Cu, is recorded in some cores. Enrichment factors (EFs) >1 for these elements and their statistical association suggest anthropogenic inputs. The most likely sources for these element enrichments (especially As) are the arsenate-based pesticides used intensively in the area during the first half of the 20th century. The transport of these elements from the nearby agricultural lands into the present river reaches appears to have been driven in part by flooding events of the CR. Flushing by river and tide flows appear to be responsible of a lower pollutant deposition in the CR compared to the adjacent Hardy River (HR). Arsenic in the buried clay units of the HR has concentrations above the probable toxic effect level (PEL) for dwelling organisms, with maximum concentrations of 30 microg g(-1). Excess (210)Pb activities ((210)Pb(xs)) indicate that fluxes of this unsupported atmospheric isotope were not constant in this estuarine environment. However, the presence of (210)Pb(xs) does indicate that these sediments accumulated during the last ~100 years. Aproximate sediment ages were estimated from the correlation of historic flooding events with the interpretation of the stratigraphic record. They are in fair agreement with the reported onset of DDT metabolites at the bottom of one core.

SUMMARY: A 3D barotropic finite difference model was adapted to reproduce the dynamics of the Ría de Vigo estuary, in the north-west corner of Spain. The model has been applied with astronomical tide and observed wind forcing data. The results are compared to data obtained by an AANDERAA DCM 12 acoustic Doppler current meter at one point of the Ría.

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Bathymetric surveys made between 1994 and 1998 in the Upper Gulf of California revealed that the bottom relief is dominated by narrow, up to 50 km long, tidal ridges and intervening troughs. These sedimentary linear features are oriented NW-SE, and run across the shallow shelf to the edge of Wagner Basin. Shallow tidal ridges near the Colorado River mouth are proposed to be active, while segments in deeper water are considered as either moribund or in burial stage. Superposition of seismic swarm epicenters and a seismic reflection section on bathymetric features indicate that two major ridge-troughs structures may be related to tectonic activity in the region. Off the Sonora coast the alignment and gradient of the isobaths matches the extension of the Cerro Prieto Fault into the Gulf. A similar gradient can be seen over the west margin of the Wagner Basin, where in 1970 a seismic swarm took place (Thatcher and Brune, 1971) overlapping with a prominent ridge-trough structure in the middle of the Upper Gulf. It is believed that these major elongated features can be linked to active geological structures reflecting the geometry of the deep basement in the Wagner Basin.