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As the adverse impacts of hydrological extremes increase in many regions of the world, a better understanding of the drivers of changes in risk and impacts is essential for effective flood and drought risk management and climate adaptation. However, there is currently a lack of comprehensive, empirical data about the processes, interactions and feedbacks in complex human-water systems leading to flood and drought impacts. Here we present a benchmark dataset containing socio-hydrological data of paired events, i.e., two floods or two droughts that occurred in the same area. The 45 paired events occurred in 42 different study areas and cover a wide range of socio-economic and hydro-climatic conditions. The dataset is unique in covering both floods and droughts, in the number of cases assessed, and in the quantity of socio-hydrological data. The benchmark dataset comprises: 1) detailed review style reports about the events and key processes between the two events of a pair; 2) the key data table containing variables that assess the indicators which characterise management shortcomings, hazard, exposure, vulnerability and impacts of all events; 3) a table of the indicators-of-change that indicate the differences between the first and second event of a pair. The advantages of the dataset are that it enables comparative analyses across all the paired events based on the indicators-of-change and allows for detailed context- and location-specific assessments based on the extensive data and reports of the individual study areas. The dataset can be used by the scientific community for exploratory data analyses e.g. focused on causal links between risk management, changes in hazard, exposure and vulnerability and flood or drought impacts. The data can also be used for the development, calibration and validation of socio-hydrological models. The dataset is available to the public through the GFZ Data Services (Kreibich et al. 2023, link for review: https://dataservices.gfz-potsdam.de/panmetaworks/review/923c14519deb04f83815ce108b48dd2581d57b90ce069bec9c948361028b8c85/).

There is an expected increase in the occurrence and severity of hydrometeorological extremes in many regions worldwide. Current research indicates that despite a positive trend in reducing drought impacts, most regions still need to adapt their monitoring practices to cope with projected drought events effectively. On the other hand, we still need a clear understanding of how a changing climate can modify the hydrological regime of catchments in the future. Therefore, it is essential to understand which drought indicators are relevant to monitoring catchments with different hydrological regimes.Therefore, this study aims to elucidate which drought indices are required to effectively monitor hydrological drought depending on the catchment’s hydrological regime, using 100 near-natural Chilean catchments with contrasting climatic conditions and hydrological regimes as a case study. For this purpose, different drought indices were computed at different temporal scales: SPI and SPEI at 3, 6, 9, 12, and 24 months; the Empirical Standardised Soil Moisture Index (ESSMI) at 3, 6, and 12 months; and a standardised snow water equivalent index (SSWEI) at 3 and 6 months. State-of-the-art gridded datasets used for computing the drought indices were: CR2MET v2.5 (a Chilean dataset based on ERA5) for precipitation and potential evapotranspiration; ERA5, ERA5-Land, and SMAP (L3 and L4) for soil moisture; and ERA5 and ERA5-Land for snow water equivalent. These indices were evaluated against the Standardised Streamflow Index (SSI) to select indices that are able to effectively monitor hydrological droughts, considering different hydrological regimes. A cross-correlation analysis and an event coincidence were used to assess which index had the highest correlation with SSI. Results showed that the indices and temporal scales used to effectively monitor hydrological droughts changed according to the catchment's hydrological regime. The results of the present work are pivotal for water managers as they provide insights on how the hydrological regime of the catchments should be considered in drought monitoring.

For more than two decades, multi-objective optimisation (MOO) has imposed a new paradigm in the calibration of hydrological models, and over the years different algorithms and calibration approaches have been developed that aim to obtain consistent parameters for some specific hydrological model. However, the development of flexible multi-objective calibration tools has been scarce, making it difficult to spread these approaches to a wide range of researchers. The objective of this work is to show the application of a new multi-objective and multi-platform R package (hydroMOPSO) for the calibration of SWAT+, a widely used semi-distributed hydrological model. In particular, in this work hydroMOPSO is used beyond the traditional adoption of multiple objective functions. Instead, a multi-period (dry and wet years), and multi-variable (point streamflows and gridded soil moisture and evapotranspiration) are used as objectives, to illustrate the flexibility of hydroMOPSO to be linked with different model input and outputs, both with different file formats and temporal frequencies. Similar approaches could be applied with other hydrological models available in R (e.g., TUWmodel, airGR, topmodel) or any other model that can be run from the system console (e.g., Raven, MODFLOW, WEAP).

Drought is one of the main hydroclimatic hazards worldwide, affecting water availability, ecosystems and socioeconomic activities. Since 2010, Central Chile (30–38°S) has been experiencing a drought with unprecedented duration and severity (also known as the Central Chile megadrought), producing drastic reductions in river flows, snow cover and reservoir levels. Nevertheless, there is limited understanding of how hydrological processes have been altered and whether such variations will persist during the 21st century. In this study, we characterize the magnitude, frequency, and duration of drought events under historical conditions and future climate scenarios across different hydrological regimes in Central Chile. To this end, we generate daily time series of streamflow, evapotranspiration, soil moisture and other hydrological variables in six case study basins with little human intervention for the period 1981-2100, using the Structure for Unifying Multiple Modeling Alternatives (SUMMA) framework and the mizuRoute model. Simulations are conducted at a 0.05º x 0.05º horizontal resolution, using a combination of the CR2MET gridded product and ERA5 outputs to obtain historical meteorological forcings, and statistically downscaled global climate model (GCM) outputs from the Coupled Model Intercomparison Project Phase 6 (CMIP6) to obtain future climate time series. Finally, we characterize drought events with the Standardized Precipitation Index (SPI), Standardized Streamflow Index (SSI), and Soil Moisture Index (SMI). The calibrated hydrologic model parameters yield daily streamflow simulations with a Kling-Gupta Efficiency (KGE) greater than 0.78 and 0.61 in all basins for the calibration and evaluation periods, respectively. The drought indices estimated for the historical period enable identifying the severe events of 1998-1999 and 2010-2020 (with standardized values smaller than -1.28); however, the magnitude and duration varies depending on the event and hydrological variable analyzed. Ongoing work seeks to examine inter-basin differences in terms of drought characteristics, along with projected changes in the frequency and intensity of this type of event.

Several long-term gridded datasets have become available in the last decades on a global scale, at increasing spatial and temporal resolution, with low latency times. These datasetshave opened new opportunities to advance Earth Sciences modelling studies at different spatial and temporal scales, especially in poorly gauged areas. However, working with (hundreds of) thousands of raster time series (e.g., for (sub)daily precipitation), usually in different vectorial and raster formats, impose high computational challenges to efficiently analyse all the gridded datasets.In this work we introduce a new R package for easy processing and analysis of raster time series, to bring the use of gridded data closer to the Earth Sciences community. This package expands the large number of spatial functions provided by the terra package by taking advantage of the time attribute of raster objects. A particular emphasis of the package is exploring and comparing gridded datasets of hydrological variables with different time frequencies (e.g., sub-hourly, hourly, daily, monthly, seasonal, annual).General purpose functions include temporal subsetting, resampling, cropping, extracting time series for points or polygons, comparing two datasets using summary statistics, and exporting a raster time series as a collection of daily/monthly/annual files, each one of them with several layers of a higher temporal frequency. Also, temporal aggregation is possible from sub-hourly to hourly/daily/weekly/monthly/annual, among others. Most functions can take advantage of multi-core computers and network clusters, to reduce the computational burden.To illustrate the use of this new package, we compared different state-of-the-art gridded precipitation products (CHIRPSv2, CMORPH v1.0, IMERGv06B, MSWXv1.0, ERA5, ERA5-Land, CR2METv2.5), all of them with different data formats and spatial resolutions, using continental Chile as a case study. However, based on the package's flexibility and ease of use, we hope the broader community of hydro-scientists and water-engineers will use it to visualise the spatio-temporal variation of key hydrological/environmental variables,to carry out time series analysis, to combinedifferent types of models and data sources, and to improve our integrated knowledge of the water cycle.

The Coastal Range in the Mediterranean segment of the Chilean active margin is a soil mantled landscape able to store fresh water and potentially support a biodiverse native forest. In this landscape, human intervention has been increasing soil erosion for ~200 yr, with the last ~45 yr experiencing intensive management of exotic tree plantations. At the same time, this landscape has been affected by a prolonged megadrought, and how the anthropogenic disturbances and hydrometeorologic trends affect sediment transport is not yet well understood. In this study we calculate a decadal-scale catchment erosion rate from suspended sediment loads and compare it with a 10-year-scale catchment denudation rate estimated from detritic 10Be. We then contrast these rates against the effects of discrete disturbances and hydroclimatic trends. Erosion/denudation rates are similar on both time scales, i.e. 0.018 ± 0.005 mm/yr and 0.024 ± 0.004 mm/yr, respectively. Recent human-made disturbances include logging operations during each season and a dense network of forestry roads, which increase structural sediment connectivity. Other disturbances include the 2010 M 8.8 Maule earthquake, and two widespread wildfires in 2015 and 2017. A decrease in suspended sediment load is observed during the wet seasons for the period 1986-2018 coinciding with a decline in several hydroclimatic parameters. The low 10-year denudation rate agrees with a landscape dominated by slow soil creep. The low 10-year-scale erosion rate and the decrease in suspended sediments, however, conflicts with both the observed disturbances and increased structural (sediment) connectivity. These observations suggest that, either suspended sediment loads and, thus, catchment erosion, are underestimated, and/or that decennial sediment detachment and transport were smeared by decreasing rainfall and streamflow. Our findings indicate that human-made disturbances and hydrometeorologic trends may result in opposite, partially offsetting effects on recent sediment transport, but both contribute to the degradation of the landscape.

The landscape of south-central Chile, originally a mosaic of pristine native forests and crops, has been converted into tree plantations and agroindustry. Farmlands and native forests have undergone a rapid conversion to fast-growing non-native pine and eucalyptus plantations, as well as irrigated fruits production for international exports. These two drivers have severely transformed the socio-ecological system, resulting in less biodiversity, more erosion, emigration and work depence, less drinking water, and a fire-prone landscape. A participatory approach helps not only to visualise tensions in the territory, but it is also useful for stakeholders to explore the possible environmental futures. However, frequently the development of land-use scenarios is mostly based on the views of experts and policymakers, missing out a wealth of local knowledge about the environment which experts seek to comprehend. This work aims at quantifying the impacts of the aforementioned land cover changes in water provision for the population and ecosystems, by incorporating the views of the people that still live in a drought-prone rural area in the construction of different narratives representing future land management scenarios. The study area is the Cauquenes River Basin, a mediterranean catchment located in central Chile, historically known for wine production and rainfed agriculture. To develop the narratives, we conducted semi-structured interviews to collect and analyse qualitative information using a coding system systematised in the Atlas.ti software. Using 2050 as the simulation target year, narratives gave us the guidelines to develop the spatial scenarios. Then, using an open-source land use change model- called CLUE-s we constructed scenarios of future land use change. The CLUE-s algorithm allocates land uses based on the suitability of each land use as well as spatial regulations. To assess the impact on water provision of each scenario, they were evaluated using a hydrological model (SWAT+).Our results identified two different narratives: i) rural development: where water availability could increase, if a protection strip is established near water courses, that is, scrublands and native forest are assigned in these areas and, rainfed agriculture is strengthened and reach the extension it had in 1990 and ii) agro-industrial development, in which the central government promotes irrigated agriculture for international export markets, at the same time, passive preservation plans for protect native forest are applied according to the current forestry regulation. We expect that this participatory approach will enrich and strengthen adaptive management capacity at the local level, to be able to face the challenges ahead presented by a drier future.

In this work we introduce hydroMOPSO, a novel multi-objective R package that combines two search mechanisms to maintain diversity of the population and accelerate its convergence towards the Pareto-optimal set: Particle Swarm Optimisation (PSO) and genetic operations. hydroMOPSO is model-independent, which allows to interface any model code with the calibration engine, including models available in R (e.g., TUWmodel, airGR, topmodel), but also any other complex models that can be run from the system console (e.g. SWAT+, Raven, WEAP). In addition, hydroMOPSO is platform-independent, which allows it to run on GNU/Linux, Mac OSX and Windows systems, among others.Considering the long execution time of some real-world models, we used three benchmark functions to search for a configuration that allows to reach the Pareto-optimal front with a low number of model evaluations, analysing different combinations of: i) the swarm size in PSO, ii) the maximum number of particles in the external archive, and iii) the maximum number of genetic operations in the external archive. In addition, the previous configuration was then evaluated against other state-of-the-art multi-objective optimisation algorithms (MMOPSO, NSGA-II, NSGA-III). Finally, hydroMOPSO was used to calibrate a GR4J-CemaNeige hydrological model implemented in the Raven modelling framework (http://raven.uwaterloo.ca), using two goodness-of-fit functions: i) the modified Kling-Gupta efficiency (KGE') and ii) the Nash-Sutcliffe efficiency with inverted flows (iNSE).Our results showed that the configuration selected for hydroMOPSO makes it very competitive or even superior against MMOPSO, NSGA-II and NSGA- III in terms of the number of function evaluations required to achieve stabilisation in the Pareto front, and also showed some advantages of using a compromise solution instead of a single-objective one for the estimation of hydrological model parameters.

The Coastal Range in the Mediterranean segment of the Chilean active margin is a soil mantled landscape of gentle hillslopes, able to store fresh water and potentially to support biodiverse native forests. In this landscape, anthropogenic intervention has been increasing soil erosion for ∼200 yr, with the last ∼45 yr experiencing intensive management on exotic tree plantations. Such intense forest management practices come along with rotational cycles as short as 9-25 yrs, depending on the tree species, dense forest road networks, and promoting wildfire susceptibility. Here we compare decadal-scale catchment erosion rates from suspended sediment loads with 104-years-scale catchment erosion rate estimated from detritic 10Be in a ∼400 km2 catchment. We relate these rates to land cover dynamics, sediment connectivity modified by forestry roads, and hydro-meteorologic trends, because the catchment has been widely disturbed by forest management practices, wildfires, and earthquakes, while an unprecedented drought started on 2010. Both, short- and long-term erosion show comparably low rates (0.018 ± 0.005 mm/yr and 0.024 ± 0.004 mm/yr). Recent human-made disturbances include logging operations every season and the building, the maintaining and the heavy machinery traffic on forestry road. Forestry roads often intersect streams, thus forming bypasses to route sediments between hillslopes and valleys. That is, increasing structural sediment connectivity. In addition, one Mw 8.8 earthquake and two widespread wildfires disturbed this catchment in 2010, 2015 and 2017, respectively. Mann-Kendall tests applied to decadal records of rainfall and streamflow resulted in decreasing trends. The suspended sediments fluxes of July also decreases in the same period, yet other subsets of that specific series were ruled out by autocorrelation or by completeness tests. The low 104-years erosion rate agrees with a landscape dominated by slow soil creep. The low 10-years-scale erosion rate, however, conflicts with the observed disturbances and the increase in structural sediment connectivity.The latter results suggest that, either the suspended sediment fluxes are underestimated, or the decennial sediment detachment and transport may be affected by the negative trends on rainfall and streamflows. Sediment mobilization depends mostly on specific thresholds of rainfall intensity on hillslopes and on water discharge in the streams, while the unprecedented drought starting in 2010 together with high water demands of fast-growing tree plantations mean a reduction in water availability. Ultimately, our findings indicate that human-made disturbances and hydrometeorologic trends may result in contrasting effects for the recent mobilization of sediments. However, both are negative for the resilience of ecosystems and then, for humans.

Risk management has reduced vulnerability to floods and droughts globally1,2, yet their impacts are still increasing3. An improved understanding of the causes of changing impacts is therefore needed, but has been hampered by a lack of empirical data4,5. On the basis of a global dataset of 45 pairs of events that occurred within the same area, we show that risk management generally reduces the impacts of floods and droughts but faces difficulties in reducing the impacts of unprecedented events of a magnitude not previously experienced. If the second event was much more hazardous than the first, its impact was almost always higher. This is because management was not designed to deal with such extreme events: for example, they exceeded the design levels of levees and reservoirs. In two success stories, the impact of the second, more hazardous, event was lower, as a result of improved risk management governance and high investment in integrated management. The observed difficulty of managing unprecedented events is alarming, given that more extreme hydrological events are projected owing to climate change3.

To foster poverty reduction in drought-prone Araucania, the Chilean Irrigation Commission is planning an important expansion of irrigated areas. Scenarios incorporating climate change (2030–2059) w...

We introduce a set of global high-resolution (0.05°) precipitation (P) climatologies corrected for bias using streamflow (Q) observations from 9372 stations worldwide. For each station, we inferred the “true” long-termPusing a Budyko curve, which is an empirical equation relating long-termP,Q, and potential evaporation. We subsequently calculated long-term bias correction factors for three state-of-the-artPclimatologies [the “WorldClim version 2” database (WorldClim V2); Climatologies at High Resolution for the Earth’s Land Surface Areas, version 1.2 (CHELSA V1.2 ); and Climate Hazards Group Precipitation Climatology, version 1 (CHPclim V1)], after which we used random-forest regression to produce global gap-free bias correction maps for thePclimatologies. Monthly climatological bias correction factors were calculated by disaggregating the long-term bias correction factors on the basis of gauge catch efficiencies. We found that all three climatologies systematically underestimatePover parts of all major mountain ranges globally, despite the explicit consideration of orography in the production of each climatology. In addition, all climatologies underestimatePat latitudes >60°N, likely because of gauge undercatch. Exceptionally high long-term correction factors (>1.5) were obtained for all threePclimatologies in Alaska, High Mountain Asia, and Chile—regions characterized by marked elevation gradients, sparse gauge networks, and significant snowfall. Using the bias-corrected WorldClim V2, we demonstrated that other widely usedPdatasets (GPCC V2015, GPCP V2.3, and MERRA-2) severely underestimatePover Chile, the Himalayas, and along the Pacific coast of North America. MeanPfor the global land surface based on the bias-corrected WorldClim V2 is 862 mm yr−1(a 9.4% increase over the original WorldClim V2). The annual and monthly bias-correctedPclimatologies have been released as the Precipitation Bias Correction (PBCOR) dataset, which is available online (http://www.gloh2o.org/pbcor/).

Study region Nile Basin, Africa. Study focus The accurate representation of precipitation ( P ) and actual evapotranspiration (ETa) patterns is crucial for water resources management, yet there remains a high spatial and temporal variability among gridded products, particularly over data-scarce regions. We evaluated the performance of eleven state-of-the-art P products and seven ETa products over the Nile Basin using a four-step procedure: (i) P products were evaluated at the monthly scale through a point-to-pixel approach; (ii) streamflow was modelled using the Random Forest machine learning technique, and simulated for well-performing catchments for 2009–2018 (to correspond with ETa product availability); (iii) ETa products were evaluated at the multiannual scale using the water balance method; and (iv) the ability of the best-performing P and ETa products to represent monthly variations in terrestrial water storage ( Δ TWS) was assessed through a comparison with GRACE Level-3 data. New hydrological insights for the region CHIRPSv2 was the best-performing P product (median monthly KGE’ of 0.80) and PMLv2 and WaPORv2.1 the best-performing ETa products over the majority of the evaluated catchments. The application of the water balance using these best-performing products captures the seasonality of Δ TWS well over the White Nile Basin, but overestimates seasonality over the Blue Nile Basin. Our study demonstrates how gridded P and ETa products can be evaluated over extremely data-scarce conditions using an easily transferable methodology.

Background/Objectives Evidence of an association between sleep disorders and extracranial atherosclerosis is limited and has not been studied in remote rural settings, where living conditions and cardiovascular risk factors are different than in urban centers. We assessed the relationship between the carotid intima-media thickness (cIMT) and sleep quality in stroke-free individuals aged ≥40 years living in rural Ecuador. Methods Applying a population-based study design, participants underwent face-to-face interviews using the Pittsburgh Sleep Quality Index (PSQI) to assess sleep quality, and sonographic examinations for measurement of the carotid intima-media thickness (cIMT). The association between the cIMT and sleep quality (as the dependent variable) was assessed by means of generalized linear models, adjusted for relevant confounders. Results The mean age of 561 participants was 60.4 ± 12.6 years (58% women). The mean PSQI was 4.6 ± 2.2 points. Of those, 79 (14%) individuals had an increased cIMT (>1 mm). A model adjusted for demographics showed a significant association between increased cIMT and the PSQI score (β: 0.602; 95% C.I.: 0.027–1.177; p = 0.040). This relationship was reduced when cardiovascular risk factors were added to the model (β: 0.514; 95% C.I.: −0.072 – 1.101; p = 0.086). When the model was adjusted for demographics and psychological distress, the association between increased cIMT and the PSQI score became significant (β: 0.573; 95% C.I.: 0.013–1.133; p = 0.045). In addition, both symptoms of depression (p = 0.032) and anxiety (p Conclusions This study shows an association between increased cIMT and the PSQI score, which is, at least, partly mediated by manifestations of psychological distress.

Mechanisms implicated in the association between neurocysticercosis (NCC) and cognitive impairment remain unknown. Atahualpa residents aged ≥ 40 years with calcified NCC were identified as case patients and paired 1:1 to age- and gender-matched controls. The selection process generated 79 pairs. Cognitive performance was measured by the Montreal Cognitive Assessment (MoCA). A conditional logistic regression model revealed no differences in MoCA scores across case patients and controls, after adjusting for education, epilepsy, depression, and hippocampal atrophy. The single covariate remaining significant was hippocampal atrophy. When participants were stratified according to this covariate, linear models showed lower MoCA scores among case patients (but not controls) with hippocampal atrophy. In a fully adjusted linear regression model, age remained as the single covariate explaining cognitive impairment among NCC patients. This study demonstrates an association between hippocampal atrophy and poor cognitive performance among patients with calcified NCC, most likely attributable to the effect of age.

Background: Data supporting a link between frailty and risk of falls is mostly confined to individuals living in urban centers, where risk factors and lifestyles are different from that of rural settings. Objective: To assess the association between frailty and risk of falls in older adults living in rural Ecuador. Design: Population-based cross-sectional study. Participants: Community-dwellers aged ≥60 years living in a rural Ecuadorian village, in whom frail status and risk of falls were assessed. Measurements: Frailty was evaluated by the Edmonton Frailty Scale (EFS) and risk of falls by the Downton Fall Risk Index (DFRI). Multivariate models were fitted to evaluate whether frailty was associated with risk of falls (dependent variable), after adjusting for demographics, alcohol intake, cardiovascular risk factors, sleep quality, symptoms of depression, and history of an overt stroke. Correlation coefficients were constructed to assess confounders modifying this association. Results: A total of 324 participants (mean age: 70.5±8 years) were included. The mean EFS score was 4.4±2.5 points, with 180 (56%) participants classified as robust, 76 (23%) as pre-frail and 68 (21%) as frail. The DFRI was positive in 87 (27%) participants. In univariate analysis, the EFS score was higher among participants with a positive DFRI (p

OBJECTIVE There is limited information on factors influencing cognitive decline in rural settings from low- and middle-income countries. Using the Atahualpa Project cohort, we aimed to assess the burden of cognitive decline in older adults living in a rural Ecuadorian village. METHODS The study included Atahualpa residents aged greater than or equal to 60 years who had a follow-up Montreal Cognitive Assessment (MoCA) repeated at least 1 year after baseline. MoCA decline was assessed by multivariable longitudinal linear models, adjusted for demographics, days between MoCA tests, cardiovascular risk factors, and neuroimaging signatures of structural brain damage. RESULTS We included 252 individuals who contributed 923.7 person-years of follow-up (mean: 3.7 ± 0.7 years). The mean baseline MoCA was 19.5 ± 4.5 points, and the follow-up MoCA was 18.1 ± 4.9 points (P = 0.001). Overall, 154 individuals (61%) had lower MoCA scores at follow-up. The best fitted longitudinal linear model showed a decline of follow-up MoCA from baseline (β: 0.14; 95% CI, 0.0-0.21; P

Information on the association between arterial stiffness and cerebral small vessel disease (cSVD) is limited and confined to white and Asian populations. More regional information is needed to confirm this association in different ethnic groups. Using the Atahualpa Project cohort, we aimed to assess whether the aortic pulse wave velocity (PWV) is associated with the total cSVD score, as well as with each of the neuroimaging signatures of cSVD, in a population of Amerindians living in rural Ecuador. Atahualpa residents aged ⩾ 60 years were offered a brain magnetic resonance imaging scan (MRI) and aortic PWV determination. An ordinal logistic regression model, adjusted for demographics and cardiovascular risk factors, was constructed to predict the total cSVD score by levels of aortic PWV. The association between the neuroimaging signatures of cSVD and the aortic PWV was assessed by adjusted logistic regression models. Of 437 candidates, 303 (69%) underwent a brain MRI and aortic PWV determinations. The total cSVD score was 0 points in 65% of individuals, 1 point in 18%, 2 points in 11%, and 3–4 points in 6%. The mean aortic PWV was 10.4 ± 1.8 m/s, which increased from 9.8 ± 1.2 to 12.3 ± 1.8 m/s in individuals with a cSVD score of 0 and 3–4, respectively ( p < 0.001). An ordinal logistic regression model showed significant association between the PWV and the cSVD score. A change of one unit of the aortic PWV increased the odds of having a higher total cSVD score by 1.73 (95% CI: 1.28–2.35; p < 0.001). In addition, individual neuroimaging signatures of cSVD, with the exception of lacunar infarcts, were associated with the aortic PWV. This study shows a significant association between the aortic PWV and total cSVD score and most of its individual components in older Amerindians.

In developing countries, an accurate representation of the spatio-temporal variability of rainfall is currently severely limited, therefore, satellite-based rainfall estimates (SREs) are promising alternatives. In this work, six state-of-the-art SREs (TRMM 3B42v7, TRMM 3B42RT, CHIRPSv2, CMORPHv1, PERSIANN-CDR, and MSWEPv2) are evaluated over three different basins in Latin-America, using a point-to-pixel comparison at daily, monthly, and seasonal timescales. Three continuous (root mean squared error, modified Kling-Gupta efficiency, and percent bias) and three categorical (probability of detection, false alarm ratio, and frequency bias) indices are used to evaluate the performance of the different SREs, and to assess if the upscaling procedure used, in CHIRPSv2 and MSWEPv2, to enable a consistent point-to-pixel comparison affects the evaluation of the SREs performance at different time scales. Our results show that for Paraiba do Sul in Brazil, MSWEPv2 presented the best performance at daily and monthly time scales, while CHIRPSv2 performed the best at these timescales over the Magdalena River Basin in Colombia. In the Imperial River Basin in Chile, MSWEPv2 and CHIRPSv2 performed the best at daily and monthly time scales, respectively. When the basins were evaluated at seasonal scale, CMORPHv1 performed the best for DJF and SON, TRMM 3B42v7 for MAM, and PERSIANN-CDR for JJA over Imperial Basin. MSWEPv2 performed the best over Paraiba do Sul Basin for all seasons and CHIRPSv2 showed the best performance over Magdalena Basin. The Modified Kling-Gupta efficiency (KGE′) proved to be a useful evaluation index because it decomposes the performance of the SREs into linear correlation, bias, and variability parameters, while the Root Mean Squared Error (RMSE) is not recommended for evaluating SREs performance because it gives more weight to high rainfall events and its results are not comparable between areas with different precipitation regimes. On the other hand, CHIRPSv2 and MSWEPv2 presented different performance, for some study areas and time scales, when evaluated with their original spatial resolution (0.05° and 0.1, respectively) with respect to the evaluation resulting after applying the spatial upscaling (to a unified 0.25), showing that the upscaling procedure might impact the SRE performance. We finally conclude that a site-specific validation is needed before using any SRE, and we recommend to evaluate the SRE performance before and after applying any upscaling procedure in order to select the SRE that best represents the spatio-temporal precipitation patterns of a site.

No information is available on the distribution of cervicocephalic atherosclerosis in Amerindians. We aimed to assess the distribution of these lesions and their correlation with cardiovascular risk factors in Amerindians living in rural Ecuador.Atahualpa residents aged ≥40years underwent head CT for assessment of carotid siphon calcifications (CSC) and sonographic examination for measurement of the carotid intima media thickness (cIMT). CSC were used as a surrogate of intracranial atherosclerosis and the cIMT as a surrogate of extracranial atherosclerosis. Linear regression and multinomial logistic regression models were fitted to assess the association between cIMT and CSC, and to evaluate differences in risk factors across individuals with atherosclerosis involving both arterial beds when compared with those with extra- or intracranial atherosclerosis alone, or no atherosclerosis.Of 590 participants, 145 had high calcium content in the carotid siphons and 87 had a cIMT1mm (25% versus 15%, P.001). Thirty-eight (7%) individuals had atherosclerosis at both vascular beds, 107 (18%) had intracranial atherosclerosis, and 49 (8%) had extracranial atherosclerosis alone. The cIMT and CSC were independently associated (P = .008). When compared with participants without atherosclerosis, those with atherosclerosis at both vascular beds were older, more often male, hypertensive and diabetic. Subjects with intracranial atherosclerosis alone were older, and those with extracranial atherosclerosis alone reported less physical activity than those without atherosclerosis.Intracranial atherosclerosis is more common than extracranial atherosclerosis in Amerindians. Traditional risk factors only explain a minority of cases of cervicocephalic atherosclerosis in this population.

Earlobe crease (ELC) has been linked to cardiovascular diseases, but information on its association with cognitive decline is limited. We aimed to assess the association between ELC and cognitive performance in community-dwelling adults living in rural Ecuador.Of 863 individuals aged ≥40 years enrolled in the Atahualpa Project, 629 (73%) were included. ELC were visually identified by two independent raters, and cognitive performance was measured by the Montreal Cognitive Assessment (MoCA). Using generalized linear and interaction models, adjusted for demographics, cardiovascular risk factors and edentulism, we assessed the association between ELC and cognitive performance, as well as the influence of age in this association.ELC was present in 246 (39%) individuals, and the mean MoCA score in the entire population was 21.9 ± 4.7 points. A generalized linear model showed no relationship between ELC presence and the MoCA score (p = 0.449). In this model, covariates remaining significant were age (p 0.001), physical activity (p = 0.014) and edentulism (p 0.001). When participants were stratified according of quartiles of age, the MoCA score did not differ according to the presence or absence of ELC. Weighted exposure-effect models - using ELC and the MoCA score as the exposure and outcome (respectively) - revealed no association between both variables.The association between ELC and the MoCA score is mainly related to age. These findings might be explained by the high prevalence of ELC and cognitive decline in older adults.

The recent increase in frequency and extent of severe wildfires in South-Central Chile is degrading the already eroded soils of the Coastal Cordillera. Spatially explicit quantification of erosion triggered by that disturbances may reveal useful information for soil conservation and land planning purposes, which is especially relevant in drinking-water catchments. We compared estimations of water erosion using a process-based and an empirical modeling approaches in a small (173 ha) burned drinking water catchment. To this end, we implemented the GeoWEPP process-based model and the RUSLE empirical approach for different scenarios of wildfire severity using remote sensing, in situ soil and hydro-meteorological data (2001-2019). Individual Hydrologic Response Units resulted in very low erosion rates in GeoWEPP respect to RUSLE, while both simulations represent low erosion rates respect to observations reported for other latitudes of the Coastal Cordillera. Those low erosion rates could be explained by low rainfall erosivity and high critical shear stress, which in turn is a consequence of soil compaction. The spatial variations of the modeled sediment yields (2001-2019) were associated both to the wildfire and to the land management at hillslopes, which involves clear cut timber harvest at most forest plantations areas. A better quantification of those erosion processes is necessary to improve the understanding of the evolution of Chilean forestry landscape, in order to prioritize efforts for soil conservation and ecosystem restoration.

An improved representation of the spatio-temporal patterns of climatological variables is crucial for ecological, agricultural, and hydrological applications and can improve the decision-making process. Traditionally, precipitation (P) and actual evaporation (ETa) are estimated using ground-based measurements from meteorological stations. However, the estimation of spatial patterns derived solely from point-based measurements is subject to large uncertainties, particularly in data-scarce regions as the Nile Basin, which has an area of about 3 million km2. This study evaluates six state-of-the-art P products (CHIRPSv2, CMORPHv1, CRU TS4.02, MSWEPv2.2, PERSIANN-CDR and GPCCv2018) and five ETa products (SSEBop, MOD16-ET, WaPOR, GLEAM and GLDAS) over the Nile Basin to identify the best-performing products. The P products were evaluated at monthly and annual temporal scales (from 1983 onwards) through a point-to-pixel approach using the modified Kling-Gupta Efficiency and its components (linear correlation, bias, and variability ratio) as continuous performance indices. The ETa products were evaluated through the water balance approach (due to the lack of ground-based ETa measurements) for 2009-2018 at the multiannual scale. Because streamflow data were not available for this period, an empirical model based on the Random Forest machine learning technique was used to estimate streamflow at 21 catchments at the monthly scale. For this purpose, we used streamflow data from 1983 to 2005 as the dependent variable, while CHIRPSv2 precipitation and ERA5 potential evaporation and temperature data were used as predictors. For the catchments where the model performed well over the validation period, streamflow estimates were generated and used for the water balance analysis. Our results show that CHIRPSv2 was the best performing P product at monthly and annual scale when compared with ground-based measurements, while WaPOR was the best-performing ETa product in the water balance evaluation. This study demonstrates how remote sensing data can be evaluated over extremely data-scarce scenarios to estimate the magnitude of key meteorological variables, yet also highlights the importance of improving data availability so that the characterisation of these variables can be further evaluated and improved.

The Intensity-Duration-Frequency (IDF) curves are crucial for urban drainage design and to mitigate the impact of extreme precipitation events and floods. However, many regions lack a high-density network of rain gauges to adequately characterise the spatial distribution of precipitation events. In this work we compute IDF curves for the South-Central Chilean region (26-56°S) using the latest version of the Integrated Multi-satellitE Retrievals for GPM (IMERGv06B) for 2001-2018, with a spatial resolution of 0.10° and half-hourly temporal frequency.First, we evaluated the performance of IMERGv06B against 344 rain gauge stations at daily, monthly and annual temporal scales using a point-to-pixel approach. The modified Kling-Gupta efficiency (KGE’) and its components (linear correlation, bias, and variability ratio) were selected as continuous indices of performance. Secondly, we fit maximum precipitation intensities from 14 long-term rain gauge stations to three probability density functions (Gumbel, Log-Pearson Type III, and GEV II) to evaluate: i) the impact of using 15-year rainfall time series in the computation of IDF curves instead of using the typical long-term periods (~ 30 years); and ii) to select the best distribution function for the study area. The Gumbel distribution was selected to obtain the maximum annual intensities for each grid-cell within the study area for 12 durations (0.5, 1, 2, 4, 6, 8, 10, 12, 18, 24, 48, and 72 h) and 6 return periods (T=2, 5, 10, 25, 50, and 100 years).The application of the Wilcoxon Mann-Whitney test indicates that differences between IDF curves obtained from 15 years of records at the 14 long-term rain gauges and those derived from 25 years of record (or more) are not statistically significant, and therefore, 15 years of record are enough (although not optimal) to compute the IDF curves. Also, our results show that IMERGv06B is able to represent the spatial distribution of precipitation at daily, monthly and annual temporal scales over the study area. Moreover, the obtained precipitation intensities showed high spatial variability, mainly over the Near North (26.0-32.2°S) and the Far South (43.7-56.0°S). Additionally, the intensities from Central Chile (32.2-36.4°S) to the Near South (36.4-43.7°S) were systematically higher compared to the intensities described in older official governmental reports, suggesting an increase in precipitation intensities during recent decades.

Headache in patients with calcified neurocysticercosis (NCC) is probably common but has been largely overlooked. We aimed to assess the presence, characteristics, and diagnosis of headache across patients with calcified NCC and their matched controls. In this case–control study nested to a population-based cohort, Atahualpa residents aged ≥ 20 years with calcified NCC were identified as case patients and paired 1:1 to age- and gender-matched randomly selected controls. A culturally adapted questionnaire was derived from the EUROLIGHT. Headache diagnosis was established according to the International Classification of Headache Disorders, 3rd edition. Conditional logistic regression models for matched paired data were fitted to assess the independent association between calcified NCC (as the exposure) and headache variables, after adjusting for education, alcohol intake, depression, and epilepsy. The selection process generated 106 case patients and their matched controls. Lifetime headache prevalence (odds ratio [OR]: 4.18; 95% Confidence Interval [CI]: 1.79–9.75; P = 0.001), current headaches (OR: 4.19; 95% CI: 1.92–9.16; P < 0.001), and intense headaches (OR: 9.47; 95% CI: 2.88–31.19; P < 0.001) were more frequent among cases than in controls. In addition, migraine (but not other forms of headache) was more frequent among subjects with calcified NCC (OR: 4.89; 95% CI: 2.36–11.39; P < 0.001). This study shows a robust epidemiological association between headache—particularly migraine—and calcified NCC.

Knowledge on the association between arterial stiffness and intracranial atherosclerosis is limited. Here, we aimed to assess whether the aortic pulse wave velocity (PWV)-used as a surrogate of arterial stiffness-might independently predict severity of carotid siphon calcifications (CSCs), used as a marker of atherosclerosis.Of 437 Atahualpa residents aged 60 years or older, 300 (69%) underwent head computed tomography (CT) (for CSC assessment), brain magnetic resonance imaging (for identification of neuroimaging signatures of cerebral small vessel disease [SVD]), and aortic PWV determinations (for arterial stiffness estimation). Ordinal logistic regression models were constructed to predict severity of CSC (as the dependent variable) according to levels of aortic PWV after adjusting for demographics, cardiovascular risk factors, and neuroimaging signatures of SVD.Grade 1 CSC were noticed in 120 (40%) subjects, grade 2 in 84 (28%), grade 3 in 73 (24%), and grade 4 in 23 (8%). The mean PWV was 10.4 ± 1.8 m/s, which increased from 9.8 ± 1.3 to 11.1 ± 2.1 m/s in individuals with grades 1 and 4 CSC, respectively (P .001). The most parsimonious ordinal logistic regression model adjusted for relevant confounders showed a significant association between aortic PWV and severity of CSC. In this model, a change of 1 unit of aortic PWV increased the odds of CSC severity by 1.22 (95% confidence interval 1.07-1.39; P = .004).The monotonically increased odds of aortic PWV among subjects with different grades of CSC, suggest that aortic PWV may be a marker for identifying candidates for CT screening in the search of CSC.

Oily fish are recommended as part of a healthy diet due to their high content of long-chain omega-3 polyunsaturated fatty acids (ω-3 PUFAs), proteins, and other nutrients. There is preliminary evidence of beneficial effects of ω-3 PUFAs in the prevention of sarcopenia (a major component of frailty). In this study, we aimed to assess the relationship between dietary oily fish intake and a measure of frailty - the Edmonton Frail Scale (EFS) score - in community-dwelling older adults living in rural coastal Ecuador. A total of 363 Atahualpa residents were enrolled. The mean fish servings per week were 8.8 ± 5.2 and mean EFS score was 5 ± 2.8 points. A linear regression model showed no association between the amount of oily fish intake and EFS scores. However, an interaction model, with participants stratified according to their median age and fish intake in quintiles, showed a significant effect for both variables on the EFS score (ß coefficient = 0.104; 95% C.I.: 0.003-0.206

PURPOSE To assess whether hippocampal atrophy develops in conjunction with clinical or subclinical epileptiform or encephalopathic activity in subjects with neurocysticercosis (NCC). METHODS Using a population-based and nested case-control study design, scalp EEGs and brain MRIs were performed in Atahualpa residents aged ≥40 years, who have imaging-confirmed NCC (case patients), as well as in age- and sex-matched NCC-free control subjects. RESULTS Sixty-two case patients and 62 control subjects were included. Encephalopathic EEG patterns were more common in five NCC subjects with epilepsy than in those without a history of seizures. Epileptiform EEG activity was noted in one patient with NCC but in none of the control subjects. This subject's focal epileptiform discharges correlated with the location of calcified cysticerci in the brain parenchyma, and the hippocampus ipsilateral to the epileptiform discharges was more atrophic than the contralateral hippocampus. The degree of hippocampal atrophy in patients with NCC without a history of seizures was significantly greater than in control subjects (P < 0.01) and tended to be even greater in patients with NCC with a history of seizures. CONCLUSIONS Hippocampal atrophy may not be exclusively related to seizure activity in patients with NCC. Other mechanisms, such as recurrent bouts of inflammation around calcified cysticerci, might explain the association between NCC and hippocampal atrophy.

Andean headwater catchments are key components of the hydrological cycle, given that they capture moisture, store water and release it for Chilean cities, industry, agriculture, and cities in Chile. However, knowledge about within-Andean catchment processes is far from clear. Most soils in the Andes derive from volcanic ash Andosols and Arenosols presenting high organic matter, high-water retention capacity and fine pores, and are very dry during summer. Despite their importance, there is little research on the hillslope hydrology of Andosols. Environmental isotopes such as Deuterium and 18-O are direct tracers for water and useful on analyzing water-soil interactions. This work explores, for the first time, the efficiency of cryogenic vacuum extraction to remove water from two contrasting soil types (Arenosols, Andosols) at five soil water retention energies (from &minus, 1500 to &minus, 33 kPa). Two experiments were carried out to analyse the impact of extraction time, and initial water content on the amount of extracted water, while a third experiment tested whether the cryogenic vacuum extraction changed the isotopic ratios after extraction. Minimum extraction times to recover over 90% of water initially in the soil samples were 40&ndash, 50 min and varied with soil texture. Minimum volume for very dry soils were 0.2 mL (loamy sand) and 1 mL (loam). After extraction, the difference between the isotope standard and the isotopic values after extraction was acceptable. Thus, we recommend this procedure for soils derived from volcanic ashes.

Objective The Evans Index (EI) is used for recognition of individuals with normal pressure hydrocephalus. However, recent studies suggest that the EI is not a reliable marker of this condition. Rather, the EI may be inversely correlated with cognitive performance, but information on this correlation is lacking. We aimed to assess the relationship between the EI and cognitive performance in community-dwelling older adults. Patients and Methods The study included 314 non-disabled, stroke-free, individuals aged ≥60 years enrolled in the Atahualpa Project undergoing brain MRI and MoCA testing. Using generalized linear models, adjusted for demographics, cardiovascular risk factors edentulism, depression, global cortical atrophy and white matter hyperintensities of vascular origin, we assessed the relationship between the EI and cognitive performance. Predictive margins of the MoCA score according to percentiles of the EI were also evaluated, after adjusting for variables reaching significance in univariate models. Results The mean EI was 0.248 ± 0.022 and the mean MoCA score was 19.7 ± 4.8 points. A fully-adjusted generalized linear model showed a significant inverse relationship between the EI and the MoCA score. Predictive models showed a decrease in the MoCA score according to increased levels of the EI (β: −3.28; 95% C.I.: −6.09 to −0.47; p = 0.022). Conclusion The independent effect of the EI on the MoCA score provides evidence of the utility of the EI to evaluate cognitive performance.

Background Basilar artery (BA) dolichoectasia has been associated with cerebral small vessel disease (SVD). However, studies have focused on stroke patients, and results cannot be extrapolated to the population at large. In this study, we aimed to assess prevalence of BA dolichoectasia and its association with SVD in community-dwelling older adults living in rural Ecuador. Methods Atahualpa residents aged ≥60 years underwent brain magnetic resonance imaging and magnetic resonance angiography of intracranial vessels. Following Smoker's criteria, the mean BA diameter plus 2 standard deviation defined ectasia. In addition, a location lateral to the lateral margin of the clivus of dorsum sellae or a bifurcation at the third ventricle floor or higher defined dolichosis. Associations between BA abnormalities and imaging markers of SVD were assessed by the use of regression models adjusted for demographics and cardiovascular risk factors. Results Of 346 participants, 11 (3.2%) had ectasia, 40 (11.6%) had dolichosis, and 47 (13.6%) had dolichoectasia (ectasia, dolichosis, or both). BA diameter was only associated with severity of white matter hyperintensities ( P = .038). Dolichosis was associated with deep cerebral microbleeds ( P = .002) but not with white matter hyperintensities. Dolichoectasia was associated with both white matter hyperintensities ( P = .031) and cerebral microbleeds ( P = .001). There were no associations with lacunar infarcts or enlarged perivascular spaces in any model. Conclusions Prevalence of BA dolichoectasia in this rural setting is similar to that reported in other populations. Associations with imaging markers of SVD differ according to whether the subject has ectasia or dolichosis.

Background: There is no information on the prevalence of symptoms related to neurotoxicity among carpenters working in underserved populations. To assess the magnitude of the problem, we conducted a population-based study in Atahualpa, a rural Ecuadorian village, where most men work as carpenters under poor safety conditions. Methods: All men aged 40–75 years living in Atahualpa were identified during a door-to-door survey and evaluated with a general demographic questionnaire, the Q16 questionnaire, the depression axis of the Depression Anxiety Stress Scale-21, and the Montreal Cognitive Assessment (MoCA). Results: Among 230 participants, 63% were carpenters. Seventy participants (30%) had a positive Q16 questionnaire (≥6 points), which suggested neurotoxicity. In a logistic regression model adjusted for age, education, alcohol intake, symptoms of depression, and MoCA score, the proportion of Q16 positive persons was 39.1% for carpenters and 15.9% for noncarpenters (odds ratio: 3.53, 95% confidence interval: 1.75–7.15, P < 0.0001). In a generalized linear model, adjusted mean scores in the Q16 questionnaire were 4.9 for carpenters and 3.6 for noncarpenters (β: 1.285, standard error: 0.347, P < 0.0001). There was no correlation between scores in the Q16 questionnaire and the MoCA (Pearson correlation coefficient = −0.02), and the only significant covariate in the multivariate linear model was age, with every 10 years of age difference contributing 0.64 points in the Q16 questionnaire. Conclusion: This study shows a high prevalence of symptoms associated with neurotoxicity among carpenters after adjusting for a number of confounders. Long-term exposure to toxic solvents is the most likely explanation to this finding.