Evaporation from the dried-up lake bed of Lake Urmia, Iran

Lake Urmia in north-western Iran was once one of the world's largest hyper-saline lakes and represented a unique ecosystem for a number of endangered species. The lake's shrinking over the past decades has attracted considerable attention and several studies have addressed its water balance. Yet, evaporation of shallow groundwater from the dried-up lake bed has not been fully quantified - despite the appreciable size of these areas (approx. 4000 km² in summer 2015). Here, we target this water cycle component by combining column experiments with upscaling and regionalisation techniques. In the experiments, we studied evaporation from two undisturbed soil cores from the exposed lake bed in a climate chamber, mimicking diurnal temperature and humidity variations in the three summer months of the study area. Despite the dropping water levels in the columns and the formation of salt crusts, evaporation rates remained remarkably constant (0.12 and 0.20 mm d^-1). This suggests that the system is not driven by slow vapour diffusion, but controlled by capillary rise in the fine-grained sediments, ensuring steady water supply to the column surface. Thus, evaporation from the dried-up lake bed can be assumed to be largely independent from the unsaturated zone thickness (within the observed water level range) and evaporation rates can be simply upscaled and regionalised by considering the satellite-derived development of dried-up lake bed areas (1998-2020). In this time-period, estimated summer evaporation from the exposed lake bed reached maximum values of 0.04 and 0.07 km³ (summer 2015). While these absolute numbers are significant (comparable to the catchment's annual urban drinking water consumption), they correspond to only 4 and 7 % of the evaporation from the open lake surface (1.06 km³).

Processes controlling the extent of groundwater pollution with chromium from tanneries in the Hazaribagh area, Dhaka, Bangladesh

The Hazaribagh industrial area in Dhaka city, the capital of Bangladesh, is considered one of the hotspots of chromium (Cr) pollution, due to excessive discharge of Cr contaminated waste over decades by approximately 150 tanneries. In 2000, elevated Cr concentrations were observed in the underlying Dupi Tila Aquifer (DTA), which is heavily deployed for drinking water supply of Dhaka city's population. In the following years, Cr concentrations in the DTA have dropped and apparently stayed low. In 2010, elevated Cr concentrations were found again in the DTA. This study aims to evaluate the status of the total Cr contamination in the surface waters, groundwater, and soils in the area, to clarify the temporal evolution of the total Cr contamination pattern in the DTA. For this, we collected water and soil samples in 2012, 2013, 2014, and 2019 for (hydro)chemical characterization and analyzed new groundwater level data on the development of the cone of depression below the city. Our study indicates that the temporal evolution of the total Cr contamination in the DTA is closely coupled to the groundwater dynamics. The rapid growth of the cone of depression due to excessive pumping resulted (i) in a disconnection of the groundwater table from the heavily contaminated Hazaribagh soils, and (ii) in an increased gradient between the contaminated surface waters and the groundwater, increasing infiltration into the groundwater. Finally, (iii) the further growth of the cone of depression resulted in an inflow of fresh groundwater from the west of Dhaka city, causing a dilution effect. Although in 2017 tanneries were moved out of the Hazaribagh area, the contaminated soils still pose a threat to groundwater quality when groundwater levels would recover.

YouTube as a crowd-generated water level archive

In view of the substantial costs associated with classic monitoring networks, participatory data collection methods can be deemed a promising option to obtain complementary data. An emerging trend in this field is social media mining, i.e., harvesting of pre-existing, crowd-generated data from social media. Although this approach is participatory in a broader sense, the users are mostly not aware of their participation in research. Inspired by this novel development, we demonstrate in this study that it is possible to derive a water level time series from the analysis of multiple YouTube videos. As an example, we studied the recent water level rise in Dahl Hith, a Saudi Arabian cave. To do so, we screened 16 YouTube videos of the cave for suitable reference points (e.g., cave graffiti). Then, we visually estimated the distances between these points and the water level and traced their changes over time. To bridge YouTube hiatuses, we considered own photos taken during two site visits. For the time period 2013-2014, we estimate a rise of 9.5m. The fact that this rise occurred at a somewhat constant rate of roughly 0.4m per month points towards a new and permanent water source, possibly two nearby lakes formed from treated sewage effluent. An anomaly in the rising rate is noted for autumn 2013 (1.3m per month). As this increased pace coincides with a cluster of rain events, we deem rapid groundwater recharge along preferential flow paths a likely cause. Despite the sacrifice in precision, we believe that YouTube harvesting may represent a viable option to gather historical water levels in data-scarce settings and that it could be adapted to other environments (e.g., flood extents). In certain areas, it might provide an additional tool for the monitoring toolbox, thereby possibly delivering hydrological data for water resources management.

Middle palaeolithic and neolithic occupations around Mundafan Palaeolake, Saudi Arabia: implications for climate change and human dispersals

The Arabian Peninsula is a key region for understanding climate change and human occupation history in a marginal environment. The Mundafan palaeolake is situated in southern Saudi Arabia, in the Rub’ al-Khali (the ‘Empty Quarter’), the world’s largest sand desert. Here we report the first discoveries of Middle Palaeolithic and Neolithic archaeological sites in association with the palaeolake. We associate the human occupations with new geochronological data, and suggest the archaeological sites date to the wet periods of Marine Isotope Stage 5 and the Early Holocene. The archaeological sites indicate that humans repeatedly penetrated the ameliorated environments of the Rub’ al-Khali. The sites probably represent short-term occupations, with the Neolithic sites focused on hunting, as indicated by points and weaponry. Middle Palaeolithic assemblages at Mundafan support a lacustrine adaptive focus in Arabia. Provenancing of obsidian artifacts indicates that Neolithic groups at Mundafan had a wide wandering range, with transport of artifacts from distant sources.

Clinical, cytogenetic, and molecular genetic characterization of two unrelated patients with different duplications of 21q

We present 2 patients with dup(21q). Patient MP01 had mild mental retardation, facial findings characteristic of Down syndrome (DS), and a terminal duplication of chromosome 21. His karyotype was 46,XY,dup(21) (q22.1-qter). Patient MP03 had mild mental retardation, minor anomalies not characteristic of DS, and a duplication of the proximal long arm of chromosome 21, karyotype 46,XX,dup(21) (q11.2-q21.2). The patients were studied with single-copy DNA sequences from 20 loci on chromosome 21 to characterize the extent of the duplicated regions at the DNA level. DNA loci from D21S55 to COL6A1 were triplicated in patient MP01 while loci from D21S13 to D21S8 were triplicated in patient MP03. Our results support the hypothesis of a critical region of chromosome 21, which in triplicate is responsible for many of the facial changes associated with DS. Other genes outside this region may also contribute to other abnormalities observed in DS.

Hyperactive behavior and minor physical anomalies

Minor physical anomalies (MPAs) are congenital abnormalities of body structure which reflect fetal maldevelopment. They originate in the same embryonic layer that produces the central nervous system, and it is reasoned that MPAs are markers of nervous system anomalies. High MPA counts have been associated with hyperactive behavior in normal and clinical populations of boys, and with inhibited behavior in normal groups of girls. The present sample of children from a longitudinal study of a Danish birth cohort show no significant sex differences in mean number of MPAs, but the male hyperactivity-MPA relation and the female inhibition-MPA relation is supported in this non-clinical sample. MPAs are not recommended for use in clinical screening or diagnosis at this time, but the evidence of a congenital, biological component to hyperactive behavior may eventually have useful implications for prevention and/or intervention.

Neurological dysfunctioning in offspring of schizophrenics in Israel and Denmark. A replication analysis

Neurological functioning was compared in children at risk for schizophrenia from samples recruited in Israel and Denmark. In both samples neurological signs were assessed in school-age children with one schizophrenic parent and a matched group of children with no mentally ill parents. Multidimensional Scalogram Analysis of data identified, in both samples, a radex structure of neurological functioning, radiating from motor to sensory-perceptual signs. In both samples, the gradient of neurological functioning differed between the offspring of schizophrenics and controls. For both the offspring of schizophrenics and controls, the largest number of children showed no or few signs of neurological dysfunctioning. A subgroup of the offspring of schizophrenics, but not the controls, showed multiple signs of neurological dysfunctioning that varied in pattern among individuals.

Amblyopia screening in kindergartens with tno stereotest

One hundred and fifty children between 3 and 6 years old were screened for amblyopia with TNO stereotest in their kindergartens. Thirty screening positive children were found of whom 3 were amblyopic with strabismus and no stereopsis. Re-testing showed that 19 children were false screening positive. Three children with refractive errors and equally impaired vision in both eyes were not detected. The test was found suitable for screening of monocular amblyopia in kindergartens, as it was easy to administrate and indicated all children with monocular amblyopia.