New groundwater-level rise data from the Rhine-Meuse delta – implications for the reconstruction of Holocene relative mean sea-level rise and differential land-level movements

We present new local groundwater-level rise data from two Late Glacial aeolian dunes, located near Barendrecht and Oud-Alblas in the western Rhine-Meuse delta. These data are based on AMS radiocarbon dating of terrestrial macrofossils, collected from the base of peat formed on the slopes of these dunes. This method avoids contamination of bulk peat samples by old soil carbon or younger rootlets and rhizomes, as well as the hardwater effect. The new data are used to assess the reliability of previously published groundwater-level index data based on conventional radiocarbon dating of bulk basal peat samples from the slopes of the Late Glacial aeolian dunes at Barendrecht, Hillegersberg, Bolnes and Wijngaarden, all located in the western Rhine-Meuse delta. Comparison of the new and published groundwater-level data shows no significant systematic difference between conventionally dated bulk peat samples and AMS-dated samples of terrestrial macrofossils. The new data from the dune at Barendrecht confirm the reliability of the younger than 6600 cal yr BP age-depth data from the dunes at Hillegersberg and near Bolnes. This result supports the validity of this part of the mean sea-level (MSL) curve for the western Netherlands. Consequently, the position of the groundwater-level curve for Flevoland (central Netherlands) below this MSL curve can most likely be attributed to differential land-level movement. The available data show that the groundwater-gradient effect in the western Rhine-Meuse delta became less than 5 cm/km after 6600 calyr BP. Finally, temporal correlation between temporary increases in local groundwater-level rise with known shifts of river courses in the delta plain suggests, that avulsions can explain sudden local deviations from the trend in groundwater-level rise. A general conclusion of this study is that a complex relationship exists between sea level and local delta-plain water levels

Factors associated with presenting late or with advanced HIV disease in the Netherlands, 1996 2014: Results from a national observational cohort

Objectives: Early testing for HIV and entry into care are crucial to optimise treatment outcomes of HIV-infected patients and to prevent spread of HIV. We examined risk factors for presentation with late or advanced disease in HIV-infected patients in the Netherlands. Methods: HIV-infected patients registered in care between January 1996 and June 2014 were selected from the ATHENA national observational HIV cohort. Risk factors for late presentation and advanced disease were analysed by multivariable logistic regression. Furthermore, geographical differences and time trends were examined. Results: Of 20 965 patients, 53% presented with latestage HIV infection, and 35% had advanced disease. Late presentation decreased from 62% (1996) to 42% (2013), while advanced disease decreased from 46% to 26%. Late presentation only declined significantly among men having sex with men (MSM; p <0.001), but not among heterosexual males (p=0.08) and females (p=0.73). Factors associated with late presentation were: heterosexual male (adjusted OR (aOR), 1.59; 95% CI 1.44 to 1.75 vs MSM), injecting drug use (2.00; CI 1.69 to 2.38), age .50 years (1.46; CI 1.33 to 1.60 vs 30.49 years), region of origin (South-East Asia 2.14; 1.80 to 2.54, sub-Saharan Africa 2.11; 1.88 to 2.36, Surinam 1.59; 1.37 to 1.84, Caribbean 1.31; 1.13 to 1.53, Latin America 1.23; 1.04 to 1.46 vs the Netherlands), and location of HIV diagnosis (hospital 3.27; 2.94 to 3.63, general practitioner 1.66; 1.50 to 1.83, antenatal screening 1.76; 1.38 to 2.34 vs sexually transmitted infection clinic). No association was found for socioeconomic status or level of urbanisation. Compared with Amsterdam, 2 regions had higher adjusted odds and 2 regions had lower odds of late presentation. Results were highly similar for advanced disease. Conclusions: Although the overall rate of late presentation is declining in the Netherlands, targeted programmes to reduce late HIV diagnoses remain needed for all risk groups, but should be prioritised for heterosexual males, migrant populations, people aged ≥50 years and certain regions in the Netherlands