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Mine waste constitutes one of the biggest environmental and management problems, both due to its quantity and its danger when they are rich in toxic elements. There is a wide variety of waste from the oxidation of ores in metal mining areas, both metal sulphide and other minerals. These residues may be enriched in potentially toxic elements that can spread and contaminate ecosystems, farmland and villages. This study has focused on the characterization and evaluation of residues derived from metal-bearing mining waste in abandoned mining areas. Mineralogy and geochemical characteristics were determined by XRD, WDXRF and TG-MS techniques. In addition, DIN 38414-S4 leaching tests were carried out to assess the risk and mobility of potentially toxic elements. Silicates and oxides were found as the main mineral groups, followed by sulphates. These tailings were particularly enriched in Zn, Pb, As, Sb and Cd, while their leachates had high or extreme metal content. Consequently, these mining wastes are considered toxic and hazardous, even for landfills. Sulphides, as the primary source, and sulphates from their oxidation, were the main sources of these pollutants. Sulphates, As, Zn, Cd and Cu determined the specific environmental impact of the different tailing types, which were grouped into different clusters according to their mineralogy and geochemistry. These results provided a better understanding of the environmental hazards associated with the different types of metal mining waste in the area studied.

Salt efflorescences from metal sulphides and their waste are important drivers of pollution both in and around mining areas. However, little is known about these supergene minerals, particularly in the mining areas of the Mediterranean. This study aims to characterise saline efflorescences and their leachates from a Mediterranean mining area located in Southeast Spain. The physicochemical characteristics were determined using stereomicroscopy and compositional analysis, with the following techniques: XRD, WDXRF and TG-MS. Additionally, to assess the risk and potential mobility of their analytes, the samples were subjected to the leaching test DIN 38414-S4. The results showed that the salt efflorescences presented a wide range of crystalline habits and colours. Sulphates were by far the largest mineral group, followed by silicates, oxides and sulphides. Their geochemistry was dominated by elements such as S or Fe, although other potentially toxic elements such as Cd, As, Zn, Pb, Ni and Cu were also present. Due to their high metal(loid) concentrations, the salt crusts studied may act as sources of environmental contaminants, demonstrating that their leachates pose a considerable risk to soil and drinking water quality. An analysis of the correlations and provenances of the components of the salt efflorescences revealed the possible presence of some rare supergene minerals of great interest, such as cuprocopiapite and Pb-As-jarosite.

Based on research carried out at 67 tailings dams in Spain: (1) tailings dams contain alternating sedimentary layers with contractive and dilative geomechanical behaviours; (2) tailings saturate quickly but drain more than 10 times slower due to the high-suction capacity of the porous sediments (2–300 MPa); and (3) over the long-term, a stationary flow regime is attained within a tailings basin. Four temporal and spatial conditions must all be present for a tailing dams flow failure to occur: (1) the tailings must experience contractive behaviour; (2) the tailings must be fully saturated; (3) the effective stress due to static or dynamic load must approach zero; and (4) the shear stress must exceed the tailings residual shear stress. Our results also indicate that the degree of saturation (S r ) is the most influential factor controlling dam stability. The pore-pressure coefficient controls geotechnical stability: when it exceeds 0.5 (S r  = 0.7), the safety factor decreases dramatically. Therefore, controlling the degree of tailings saturation is instrumental to preventing dam failures, and can be achieved using a double drainage system, one for the unconsolidated foundation materials and another for the overlying tailings.

The aim of this work is to investigate the causes of the El Descargador tailings dam failure, at the mine district Cartagena–La Unión (SE Spain), in October 1963. Dam stability back analyses have been carried out by applying a geotechnical and geophysical approach. The failure occurred in the form of several landslides in five different points along the dam structure. The rise in the pore pressure and the steeped slopes of the tails, scaling up to 40° in some sectors, were the main causal preparatory factors. Here we propose that static liquefaction is the most plausible cause of the tailings dam flow failure. The presence of sand dikes and sand volcanoes with atypical stratigraphic architecture, both in the lagoon and at the surfaces exposed in the landslide areas, as well as the evidence of conspicuous sand fraction on the surface support the occurrence of the liquefaction processes. Major landslides were located near the drainage pipe and the flow directions were controlled by its position. Our results reveal that the liquefaction processes were triggered and aggravated by the poor drainage capability of the tailings dam structure.

The aim of this thesis was to contribute to the interpretation of the geogenic and anthropogenic factors, at local (hydrographic basin) and regional levels, that control the geoavailability (solubility and mobility) of Ni, Cu, Zn, As, Cd, and Pb in the Sierra Minera de Cartagena – La Unión, as well as to evaluate the influence of the abandoned mining landscape on the Campo de Cartagena and Mar Menor lagoon. The study period extended from 2003 to 2012. Across the large plain of 1600 km2 that forms the Campo de Cartagena, 15 weather stations were monitored to collect 920 rainwater samples. In addition, 179 surface runoff water samples were gathered in 13 ephemeral watercourses, 127 springwater samples in 5 springs, 16 seawater samples in 8 wadi outlets, 15 efflorescent sulfate salts, 7 types of mine wastes, and 23 types of parent materials. The assessment of such variety of specimens helped to understand the mechanisms that make Ni, Cu, Zn, As, Cd, and Pb geoavailable in the Sierra Minera of Cartagena – La Unión. For this purpose, these trace elements were studied in the geological context, taking into account their geochemical cycles, the different types of mining and metallurgical wastes present in the derelict mining site, and the sphere of influence to the bordering areas. The results have confirmed that geoavailability of trace metals in the Sierra Minera is governed by physico-chemical weathering of mining and metallurgical wastes, as well as by the oxidation of metallic sulfides associated to the Pb-Zn ores. Regarding the transport, dispersion, and deposition mechanisms of Ni, Cu, Zn, As, Cd, and Pb, the geoavailable trace-metal mass balance for Mar Menor lagoon disclosed that aeolian erosion transfered 81% of the overall input of metal pollutants coming from the Sierra Minera, groundwater input contributed 16%, and watershed stream input only represented 3%. This proved that scattering of those trace elements is NOT controlled by continental water bodies (surface runoff and groundwater).

We explore the relationship between collaborations in writing papers and the academic productivity of economists and, particularly, we describe the magnitude and intensity of co-authorship among economists. To that end, we employ interaction maps from Complex Systems methods to study the global properties of specific networks. We use 8,253 JCR papers from ISI-WOK, published by 5,188 economists from Spanish institutions, and their co-authors, up to 8,202 researchers, from 2002 to 2014, to identify and determine the collaborative structure of economics research in Spain, with its primary communities and figures of influence. Our results indicate that centrality and productivity are correlated, particularly with respect to a local estimator of centrality (page rank), and we provide certain recommendations, such as promoting interactions among highly productive authors who have few co-authors with other researchers in their environment, or recommending that authors who may be well-positioned but minimally productive strive to improve their productivity.

Background Recently developed blood markers for Alzheimer's disease (AD) detection have high accuracy but usually require ultra-sensitive analytic tools not commonly available in clinical laboratories, and their performance in clinical practice is unknown. Methods We analyzed plasma samples from 290 consecutive participants that underwent lumbar puncture in routine clinical practice in a specialized memory clinic (66 cognitively unimpaired, 130 participants with mild cognitive impairment, and 94 with dementia). Participants were classified as amyloid positive (A +) or negative (A-) according to CSF Aβ 1–42 /Aβ 1–40 ratio. Plasma pTau 217 , pTau 181 , Aβ 1–42 and Aβ 1–40 were measured in the fully-automated LUMIPULSE platform. We used linear regression to compare plasma biomarkers concentrations between A + and A- groups, evaluated Spearman’s correlation between plasma and CSF and performed ROC analyses to assess their diagnostic accuracy to detect brain amyloidosis as determined by CSF Aβ 1–42 /Aβ 1–40 ratio. We analyzed the concordance of pTau 217 with CSF amyloidosis. Results Plasma pTau 217 and pTau 181 concentration were higher in A + than A- while the plasma Aβ 1–42 /Aβ 1–40 ratio was lower in A + compared to A-. pTau 181 and the Aβ 1–42 /Aβ 1–40 ratio showed moderate correlation between plasma and CSF (Rho = 0.66 and 0.69, respectively). The areas under the ROC curve to discriminate A + from A- participants were 0.94 (95% CI 0.92–0.97) for pTau 217 , and 0.88 (95% CI 0.84–0.92) for both pTau 181 and Aβ 1–42 /Aβ 1–40 . Chronic kidney disease (CKD) was related to increased plasma biomarker concentrations, but ratios were less affected. Plasma pTau 217 had the highest fold change (× 3.2) and showed high predictive capability in discriminating A + from A-, having 4–7% misclassification rate. The global accuracy of plasma pTau 217 using a two-threshold approach was robust in symptomatic groups, exceeding 90%. Conclusion The evaluation of blood biomarkers on an automated platform exhibited high diagnostic accuracy for AD pathophysiology, and pTau 217 showed excellent diagnostic accuracy to identify participants with AD in a consecutive sample representing the routine clinical practice in a specialized memory unit.

Leishmania infantum is the etiological agent of zoonotic visceral leishmaniasis (ZVL). The disease is endemic in Central and South America, Central and South East Asia, and the Mediterranean basin. Dogs are the main reservoir, with an estimated prevalence of approximately 2.5 million dogs in Southern Europe. Current treatments cause side effects, disease recurrence, and drug resistance. Therefore, the development of vaccines against canine leishmaniasis is necessary. We have generated a DNA vaccine based on the non-replicative antibiotic resistance marker-free plasmid vector pPAL that contains the encoding gene for the L. infantum activated protein kinase C receptor analog (LACK). Homologous pPAL-LACK prime-boost intranasal administration confers efficacious protection in Beagle dogs with a reduction of clinical signs and a statistically significant reduction of the parasite burden in the bone marrow of more than 90% of dogs after experimental infection with highly infective promastigotes. This DNA vaccine elicits a robust cellular immune response skewed towards the Th1 profile.

This study aimed to evaluate the impact of APOE4 homozygosity on Alzheimer's disease (AD) by examining its clinical, pathological and biomarker changes to see whether APOE4 homozygotes constitute a distinct, genetically determined form of AD. Data from the National Alzheimer's Coordinating Center and five large cohorts with AD biomarkers were analyzed. The analysis included 3,297 individuals for the pathological study and 10,039 for the clinical study. Findings revealed that almost all APOE4 homozygotes exhibited AD pathology and had significantly higher levels of AD biomarkers from age 55 compared to APOE3 homozygotes. By age 65, nearly all had abnormal amyloid levels in cerebrospinal fluid, and 75% had positive amyloid scans, with the prevalence of these markers increasing with age, indicating near-full penetrance of AD biology in APOE4 homozygotes. The age of symptom onset was earlier in APOE4 homozygotes at 65.1, with a narrower 95% prediction interval than APOE3 homozygotes. The predictability of symptom onset and the sequence of biomarker changes in APOE4 homozygotes mirrored those in autosomal dominant AD and Down syndrome. However, in the dementia stage, there were no differences in amyloid or tau positron emission tomography across haplotypes, despite earlier clinical and biomarker changes. The study concludes that APOE4 homozygotes represent a genetic form of AD, suggesting the need for individualized prevention strategies, clinical trials and treatments.

This study aimed to evaluate the impact of APOE4 homozygosity on Alzheimer’s disease (AD) by examining its clinical, pathological and biomarker changes to see whether APOE4 homozygotes constitute a distinct, genetically determined form of AD. Data from the National Alzheimer’s Coordinating Center and five large cohorts with AD biomarkers were analyzed. The analysis included 3,297 individuals for the pathological study and 10,039 for the clinical study. Findings revealed that almost all APOE4 homozygotes exhibited AD pathology and had significantly higher levels of AD biomarkers from age 55 compared to APOE3 homozygotes. By age 65, nearly all had abnormal amyloid levels in cerebrospinal fluid, and 75% had positive amyloid scans, with the prevalence of these markers increasing with age, indicating near-full penetrance of AD biology in APOE4 homozygotes. The age of symptom onset was earlier in APOE4 homozygotes at 65.1, with a narrower 95% prediction interval than APOE3 homozygotes. The predictability of symptom onset and the sequence of biomarker changes in APOE4 homozygotes mirrored those in autosomal dominant AD and Down syndrome. However, in the dementia stage, there were no differences in amyloid or tau positron emission tomography across haplotypes, despite earlier clinical and biomarker changes. The study concludes that APOE4 homozygotes represent a genetic form of AD, suggesting the need for individualized prevention strategies, clinical trials and treatments. The study on APOE4 homozygosity indicates a genetic variant of Alzheimer’s disease with early symptom onset and distinct biomarker progression, highlighting the need for specialized treatment approaches.