27 research outputs found
Sedimentological and palaeohydrological characterization of Late Pleistocene and Holocene tufa mound palaeolakes using trenching methods in the Spanish Pyrenees
Lakes developed in the inner depressions of tufa mounds are rare geomorphic features and still poorly understood. Sedimentation in this unusual type of endorheic lake with a very restricted catchment area is highly sensitive to environmental and hydrological changes. The Isona tufa mound complex, north-eastern Iberian Peninsula, is associated with the discharge zone of a confined artesian aquifer and comprises 11 tufa mounds consisting of an annular rimstone enclosing a central depression filled with lake deposits. Data gathered from trenches excavated in four palaeolakes located within three different morphostratigraphic units permitted a precise analysis of the geometrical characteristics and stratigraphic relationships of the deposits and provided a sedimentation model for the Late Quaternary infilling of the spring-fed lakes. The work illustrates that trenches allow a precise characterization of the stratigraphic arrangements, lateral facies changes and deformation structures, which are not apparent in studies relying solely on borehole records, and facilitate sampling for dating and geochemical analyses. The five sedimentary facies described represent different evolutionary stages of the lakes, including: (i) carbonate-rich palustrine deposits probably related to periods with strong hydrological seasonality; (ii) massive highly bioturbated organic ooze; (iii) banded organic carbonate-rich facies associated with an increase in the regional effective moisture; (iv) finegrained quartz-rich aeolian/slope-wash sediments; and (v) colluvial facies deposited following the desiccation of the lakes located at higher altitudes. Geochemical and sedimentological analyses of the lacustrine sequences provided information on the palaeohydrological evolution of the Isona tufa mound complex and the palaeoenvironmental conditions of the area over the last 28 ka. Radiometric dating suggests that deposition occurred simultaneously at ca 22 ka in palaeolakes situated at different elevations. A drop in the piezometric level prompted by the opening of springs at lower altitudes probably caused the deactivation of the upper springs and the desiccation of the lakes. Arid conditions prevailed in the area during the Late Glacial and the early Holocene (28·0 to 8·5 ka BP). More humid conditions recorded from 8·5 to 4·2 ka and again since 1·7 ka are in accordance with palaeoenvironmental reconstructions available in the Western Mediterranean since the Last Glacial Maximum
Identifying the boundaries of sinkholes and subsidence areas via trenching and establishing setback distances
One of the most effective mitigation strategies in sinkhole areas is the exclusion of sinkholes and their vicinity to construction. The application of this preventive measure requires precise mapping of the boundaries of the areas affected by subsidence and the establishment of adequate setback distances, which is an important policy issue with significant economic implications. Through the investigation of several buried sinkholes in the mantled evaporite karst of the Ebro Valley by trenching, this work illustrates that the actual extent of the subsidence areas may be much larger than that inferred from surface mapping and geophysical surveys. The objective and accurate subsurface information acquired from trenches on the outer edge of the deformed ground revealed sinkhole radii 2–3 times larger than initially estimated, increasing one order of magnitude the sinkhole area. Trenches can therefore help to reduce mapping uncertainties and the size of setbacks. Moreover, the trenching technique, in combination with geochronological data and retrodeformation analyses, provides critical information on the subsidence phenomena and the characteristics of the sinkholes relevant to hazard assessment. Since recommended setback distances found in the existing literature are highly variable and rather arbitrary, we include a discussion here on the main factors that should be considered when defining setback zones for sinkholes
Clinical Prognosis of Right-Sided Infective Endocarditis not Associated with Cardiac Devices or Intravenous Drug use : a Cohort Study and Meta-Analysis
Right-sided infective endocarditis (RSIE), classically associated with intravenous drug use or intracardiac devices, is considered a good-prognosis infective endocarditis (IE) form. However, predisposing factors and prognosis for "NODID" RSIE (NOt associated with cardiac Devices or Intravenous Drug use) remain unclear. The aim of this study was to evaluate predisposing factors and prognosis of NODID RSIE compared to other RSIE forms. A retrospective cohort study (January 2008-January 2019) was conducted in a reference center on 300 patients diagnosed with IE. Endocarditis-related events were defined as related to IE in mortality or open-heart surgery during follow-up. A review and meta-analysis of associated literature (January 2008-January 2019) were also performed. Fifty-seven patients presented RSIE (19%), 22 of which were NODID RSIE (39%). Use of intravascular catheters (23% vs 3%; p = 0.027) and congenital heart diseases (18% vs 0%; p = 0.019) were associated with NODID RSIE. This group had a higher in-hospital mortality (23% vs 3%; p = 0.027) and endocarditis-related event rates (41% vs 6%; p = 0.001) than non-NODID RSIE. Furthermore, NODID RSIE was independently associated with in-hospital endocarditis-related events (OR = 19.29; 95%CI:2.23-167.16; p = 0.007). Our meta-analysis evaluated four studies and identified 96 cases (30%) of NODID RSIE from 320 total RSIE cases. NODID RSIE patients demonstrated higher in-hospital mortality (RR = 2.81; 95%CI:1.61-4.90; p < 0.001; I = 0.0%) and necessity of open-heart surgery (RR = 13.89; 95%CI:4.14-46.60; p < 0.001; I = 0.0%) than non-NODID RSIE cases. Our study suggests that NODID RSIE has the highest endocarditis-related event rate and in-hospital mortality among RSIE cases and therefore should not be considered a good-prognosis IE
The chert from the Castelltallat Formation (south-central Pyrenees): archaeometric characterisation and archaeological implications
Chert from the limestones and marly limestones of Castelltallat Formation (Ebro Basin) was widely used throughout prehistoric times in north-eastern Iberia to produce stone tools due to its properties and accessibility. A rough estimate indicates that this rock¿either as raw material or as lithic products¿was distributed mainly to the north of the outcrops, over an area of 6000-8000 km2. However, other rocks in the area have similar characteristics which can lead to confusion in the interpretation of its prehistoric use and distribution. In order to establish useful archaeometric criteria for differentiating this chert from other similar, the Castelltallat chert is characterised in petrographic, mineralogical and geochemical terms. The chert nodules are found to be homogenous at the macroscopic and microscopic level, with a significant presence of bioclasts, thus indicating they might be formed in a freshwater lake environment by the early diagenetic replacement of carbonates in shallow waters. The mineralogical composition is homogeneously uniform and of a flint type, characterised by an almost exclusive predominance of quartz, without any opaline phases, and a variable proportion of moganite. The iron oxide content is very low, whereas its chemical composition is unusually high in uranium which correlates positively with carbonate content and negatively with silica. Archaeometrical parameters are provided to reach a proper identification of tools knapped with this chert. This way, chert from Castelltallat Formation turns out to be a valuable lithological marker to evaluate the range of mobility of the human groups who lived in the north-eastern Iberia and their contacts with neighbouring areas
Identificación de flujos entre acuíferos a nivel regional en base a datos hidroquímicos (Alt Empordà, NE España)
A escala regional, los flujos de agua subterránea entre formaciones hidrogeológicas condicionan su ba lance hídrico y, con él, su régimen de explotación. En este estudio se caracteriza la dinámica hidrogeológica a nivel regional de la depresión del Alt Empordà (Girona, NE España) en base a datos hidroquímicos, con el objetivo de identificar flujos de agua subterránea entre las formaciones que constituyen la zona de recarga (relieves circundantes) y la depresión. En este sistema, el ión sulfato resulta un trazador adecuado para identificar los procesos hidroquímicos y de mezcla que acontecen en este zona. Los datos presentados sugieren que la presencia de sulfato, y por consiguiente la recarga, se debe a aportaciones de flujos profundos, en algunos casos desde las unidades geológicas inferiores, ajenos a la recarga local por precipitación desde la superficie.At a regional scale, groundwater flow between aquifer systems controls their water budget and, therefore, its exploitation regime. This study characterizes the hydrogeology at a regional level of the Alt Empordà Basin (Girona, NE Spain). Our goal consists in recognizing recharge flowpaths, based on hydrochemical data, between the aquifer systems located in the ranges (recharge) areas and these within the basin. Sulfate stands as an appropriate tracer to identify hydrochemical as well as mixing processes and, therefore, recharge relationships. Field data suggest that sulfate occurrence is related to deep groundwater fluxes unrelated to the local rainfall recharge.Universidad Nacional de La Plat
Systemic pro-inflammatory response identifies patients with cancer with adverse outcomes from SARS-CoV-2 infection: the OnCovid Inflammatory Score
Background: Patients with cancer are particularly susceptible to SARS-CoV-2 infection. The systemic inflammatory response is a pathogenic mechanism shared by cancer progression and COVID-19. We investigated systemic inflammation as a driver of severity and mortality from COVID-19, evaluating the prognostic role of commonly used inflammatory indices in SARS-CoV-2-infected patients with cancer accrued to the OnCovid study. Methods: In a multicenter cohort of SARS-CoV-2-infected patients with cancer in Europe, we evaluated dynamic changes in neutrophil:lymphocyte ratio (NLR); platelet:lymphocyte ratio (PLR); Prognostic Nutritional Index (PNI), renamed the OnCovid Inflammatory Score (OIS); modified Glasgow Prognostic Score (mGPS); and Prognostic Index (PI) in relation to oncological and COVID-19 infection features, testing their prognostic potential in independent training (n=529) and validation (n=542) sets. Results: We evaluated 1071 eligible patients, of which 625 (58.3%) were men, and 420 were patients with malignancy in advanced stage (39.2%), most commonly genitourinary (n=216, 20.2%). 844 (78.8%) had ≥1 comorbidity and 754 (70.4%) had ≥1 COVID-19 complication. NLR, OIS, and mGPS worsened at COVID-19 diagnosis compared with pre-COVID-19 measurement (p<0.01), recovering in survivors to pre-COVID-19 levels. Patients in poorer risk categories for each index except the PLR exhibited higher mortality rates (p<0.001) and shorter median overall survival in the training and validation sets (p<0.01). Multivariable analyses revealed the OIS to be most independently predictive of survival (validation set HR 2.48, 95% CI 1.47 to 4.20, p=0.001; adjusted concordance index score 0.611). Conclusions: Systemic inflammation is a validated prognostic domain in SARS-CoV-2-infected patients with cancer and can be used as a bedside predictor of adverse outcome. Lymphocytopenia and hypoalbuminemia as computed by the OIS are independently predictive of severe COVID-19, supporting their use for risk stratification. Reversal of the COVID-19-induced proinflammatory state is a putative therapeutic strategy in patients with cancer
The SITLESS project: Exercise referral schemes enhanced by self-management strategies to battle sedentary behaviour in older adults: Study protocol for a randomised controlled trial
Abstract Background Older adults are the fastest growing segment of the world‘s population. Recent evidence indicates that excessive sitting time is harmful to health, independent of meeting the recommended moderate to vigorous physical activity (PA) guidelines. The SITLESS project aims to determine whether exercise referral schemes (ERS) can be enhanced by self-management strategies (SMSs) to reduce sedentary behaviour (SB), increase PA and improve health, quality of life and function in the long term, as well as psychosocial outcomes in community-dwelling older European citizens from four countries, within a three-armed pragmatic randomised controlled trial, compared with ERS alone and also with general recommendations about PA. Methods A total of 1338 older adults will be included in this study, recruited from four European countries through different existing primary prevention pathways. Participants will be randomly allocated into an ERS of 16 weeks (32 sessions, 45–60 min per session), ERS enhanced by seven sessions of SMSs and four telephone prompts, or a control group. Outcomes will be assessed at baseline, month 4 (end of ERS intervention), month 16 (12 months post intervention) and month 22 (18 months post intervention). Primary outcomes will include measures of SB (time spent sedentary) and PA (counts per minute). Secondary outcomes will include muscle and physical function, health economics’ related outcomes, anthropometry, quality of life, social networks, anxiety and depressive symptoms, disability, fear of falling, executive function and fatigue. A process evaluation will be conducted throughout the trial. The full analysis set will follow an intention-to-treat principle and will include all randomised participants for whom a baseline assessment is conducted. The study hypothesis will be tested with mixed linear models with repeated measures, to assess changes in the main outcomes (SB and PA) over time (baseline to month 22) and between study arms. Discussion The findings of this study may help inform the design and implementation of more effective interventions to reduce SB and increase PA levels, and hence improve long-term health outcomes in the older adult population. SITLESS aims to support policy-makers in deciding how or whether ERS should be further implemented or restructured in order to increase its adherence, impact and cost-effectiveness. Trial registration ClinicalTrials.gov, NCT02629666 . Registered 19 November 2015
The chert from the Castelltallat Formation (south-central Pyrenees): archaeometric characterisation and archaeological implications
Chert from the limestones and marly limestones of Castelltallat Formation (Ebro Basin) was widely used throughout prehistoric times in north-eastern Iberia to produce stone tools due to its properties and accessibility. A rough estimate indicates that this rock¿either as raw material or as lithic products¿was distributed mainly to the north of the outcrops, over an area of 6000-8000 km2. However, other rocks in the area have similar characteristics which can lead to confusion in the interpretation of its prehistoric use and distribution. In order to establish useful archaeometric criteria for differentiating this chert from other similar, the Castelltallat chert is characterised in petrographic, mineralogical and geochemical terms. The chert nodules are found to be homogenous at the macroscopic and microscopic level, with a significant presence of bioclasts, thus indicating they might be formed in a freshwater lake environment by the early diagenetic replacement of carbonates in shallow waters. The mineralogical composition is homogeneously uniform and of a flint type, characterised by an almost exclusive predominance of quartz, without any opaline phases, and a variable proportion of moganite. The iron oxide content is very low, whereas its chemical composition is unusually high in uranium which correlates positively with carbonate content and negatively with silica. Archaeometrical parameters are provided to reach a proper identification of tools knapped with this chert. This way, chert from Castelltallat Formation turns out to be a valuable lithological marker to evaluate the range of mobility of the human groups who lived in the north-eastern Iberia and their contacts with neighbouring areas