68 research outputs found
Stress and strain analysis and induced seismicity in geological gas storage (Yela, Spain)
Geologic gas storage is a sustainable strategy to store energy in underground reservoirs in order to be used under demand. Injection and withdrawal gas operations could trigger induced seismicity according to the tectonic constrains of the reservoir. The study of the active stress/strain fields shows the properties of the fault patterns that can be involved in induced seismicity. In our work, we have determined the strain/stress field in the Yela underground gas storage, an Upper Cretaceous carbonate reservoir located in central Spain. Slickensides on fault planes were measured from Cretaceous, Miocene and Quaternary rocks. Results show a strain field with ey (maximum horizontal shortening) oriented NW-SE. This field was compressional during the early Miocene, switching off to extensional from late Miocene to present-day. Our results suggest that NNW-SSE and NW-SE oriented faults could act as an effective pathway for gas leakage and prone to trigger induced seismicity. Moreover, 141 small earthquakes (Mmax 2.3) were recorded during underground operations in Yela. Peaks of earthquakes appear seasonally from November to February, in coincidence with the injection operations prior to the winter withdrawal. Working at its maximum gas storage volume, earthquake peaks decreased in intensity and magnitude from 2017 to 2021, and show a time lag of 3 months from the month of maximum volume injection to the earthquake occurrenc
Neogene to recent contraction and basin inversion along the Nubia-Iberia boundary in SW Iberia
The SW of Iberia is currently undergoing compression related to the convergence between Nubia and Iberia. Multiple compressive structures, and their related seismic activity, have been documented along the diffuse Nubia-Iberia plate boundary, including the Gorringe bank west of the Gulf of Cadiz, and the Betic-Rif orogen to the east. Despite seismic activity indicating a dominant compressive stress along the Algarve margin in the Gulf of Cadiz, the structures at the origin of this seismicity remain elusive. This paper documents the contractional structures that provide linkage across the Gulf of Cadiz and play a major role in defining the present-day seismicity and bathymetry of this area. The structures described in this paper caused the Neogene inversion of the Jurassic oblique passive margin that formed between the central Atlantic and the Ligurian Tethys. This example of a partially inverted margin provides insights into the factors that condition the inversion of passive margins
A generic image retrieval method for date estimation of historical document collections
Date estimation of historical document images is a challenging problem, with several contributions in the literature that lack of the ability to generalize from one dataset to others. This paper presents a robust date estimation system based in a retrieval approach that generalizes well in front of heterogeneous collections. we use a ranking loss function named smooth-nDCG to train a Convolutional Neural Network that learns an ordination of documents for each problem. One of the main usages of the presented approach is as a tool for historical contextual retrieval. It means that scholars could perform comparative analysis of historical images from big datasets in terms of the period where they were produced. We provide experimental evaluation on different types of documents from real datasets of manuscript and newspaper images
Vertical Niche Partitioning of Archaea and Bacteria Linked to Shifts in Dissolved Organic Matter Quality and Hydrography in North Atlantic Waters
Understanding the factors that modulate prokaryotic assemblages and their niche partitioning in marine environments is a longstanding challenge in marine microbial ecology. This study analyzes amplicon sequence variant (ASV) diversity and co-occurrence of prokaryotic (Archaea and Bacteria) communities through coastal-oceanic gradients in the NW Iberian upwelling system and adjacent open-ocean (Atlantic Ocean). Biogeographic patterns were investigated in relation with environmental conditions, mainly focusing on the optical signature of the dissolved organic matter (DOM). Alpha- and beta-diversity were horizontally homogeneous [with the only exception of Archaea (∼1700 m depth), attributed to the influence of Mediterranean water, MW], while beta-diversity was significantly vertically stratified. Prokaryotic communities were structured in four clusters (upper subsurface, lower subsurface, intermediate, and deep clusters). Deep (>2000 m) archaeal and bacterial assemblages, and intermediate (500-2000 m) Bacteria (mainly SAR202 and SAR406), were significantly related to humic-like DOM (FDOM-M), while intermediate Archaea were additionally related to biogeochemical attributes of the high-salinity signature of MW. Lower subsurface (100-500 m) Archaea (particularly one ASV belonging to the genus Candidatus Nitrosopelagicus) were mainly related to the imprint of high-salinity MW, while upper subsurface (≤100 m) archaeal assemblages (particularly some ASVs belonging to Marine Group II) were linked to protein-like DOM (aCDOM254). Conversely, both upper and lower subsurface bacterial assemblages were mainly linked to aCDOM254 (particularly ASVs belonging to Rhodobacteraceae, Cyanobacteria, and Flavobacteriaceae) and nitrite concentration (mainly members of Planctomycetes). Most importantly, our analysis unveiled depth-ecotypes, such as the ASVs MarG.II_1 belonging to the archaeal deep cluster (linked to FDOM-M) and MarG.II_2 belonging to the upper subsurface cluster (related to FDOM-T and aCDOM254). This result strongly suggests DOM-mediated vertical niche differentiation, with further implications for ecosystem functioning. Similarly, positive and negative co-occurrence relationships also suggested niche partitioning (e.g., between the closely related ASVs Thaum._Nit._Nit._Nit._1 and _2) and competitive exclusion (e.g., between Thaum._Nit._Nit._Nit._4 and _5), supporting the finding of non-randomly, vertically structured prokaryotic communities. Overall, differences between Archaea and Bacteria and among closely related ASVs were revealed in their preferential relationship with compositional changes in the DOM pool and environmental forcing. Our results provide new insights on the ecological processes shaping prokaryotic assembly and biogeography.Versión del edito
3D reconstruction of syn-tectonic strata deposited during the inversion of salt-related structures : insights from the Llert syncline (South-central Pyrenees)
The Llert syncline is located in the South-central Pyrenees, between the eastern termination of the EW-trending Cotiella Basin and the north-western limb of the NS-trending Turbón-Serrado fold system. The Cotiella Basin is an inverted upper Coniacian-lower Santonian salt-floored post-rift extensional basin developed along the northern Iberian rift system. The Turbón-Serrado fold system consists of upper Santonian - Maastrichtian contractional salt-cored anticlines developed along an inverted transfer zone of the Pyrenean rift system. Based on field research, this paper presents a 3D reconstruction of the Llert syncline in order to further constrain the transition between these oblique salt-related structures. Our results suggest that the evolution of the Llert syncline was mainly controlled by tectonic shortening related to the tectonic inversion of the Cotiella Basin synchronously to the growth of the Turbón-Serrado detachment anticline, and by the pre-compressional structural framework of the Pyrenean rift system. Our contribution provides new insight into the geometric and kinematic relationships of structures developed during the inversion of passive margins involving salt
An active tectonic field for CO2 storage management: the Hontomín onshore case study (Spain)
One of the concerns of underground CO2 onshore
storage is the triggering of induced seismicity and fault reactivation by the pore pressure increasing. Hence, a comprehensive analysis of the tectonic parameters involved in the
storage rock formation is mandatory for safety management
operations. Unquestionably, active faults and seal faults depicting the storage bulk are relevant parameters to be considered. However, there is a lack of analysis of the active
tectonic strain field affecting these faults during the CO2
storage monitoring. The advantage of reconstructing the tectonic field is the possibility to determine the strain trajectories and describing the fault patterns affecting the reservoir
rock. In this work, we adapt a methodology of systematic
geostructural analysis to underground CO2 storage, based on
the calculation of the strain field from kinematics indicators
on the fault planes (ey and ex for the maximum and minimum horizontal shortening, respectively). This methodology
is based on a statistical analysis of individual strain tensor
solutions obtained from fresh outcrops from the Triassic to
the Miocene. Consequently, we have collected 447 fault data
in 32 field stations located within a 20 km radius. The understanding of the fault sets’ role for underground fluid circulation can also be established, helping further analysis of
CO2 leakage and seepage. We have applied this methodology
to Hontomín onshore CO2 storage facilities (central Spain).
The geology of the area and the number of high-quality outcrops made this site a good candidate for studying the strain
field from kinematics fault analysis. The results indicate a
strike-slip tectonic regime with maximum horizontal shortening with a 160 and 50◦ E trend for the local regime, which
activates NE–SW strike-slip faults. A regional extensional
tectonic field was also recognized with a N–S trend, which
activates N–S extensional faults, and NNE–SSW and NNW–
SSE strike-slip faults, measured in the Cretaceous limestone
on top of the Hontomín facilities. Monitoring these faults
within the reservoir is suggested in addition to the possibility of obtaining a focal mechanism solutions for microearthquakes (M < 3)This work has been partially supported by the European Project ENOS: ENabling Onshore CO2 Storage in Europe, H2020 Project ID: 653718 and the Spanish project 3GEO, CGL2017-83931-C3-2-P, MICIU-FEDE
Contribution of CSF biomarkers to early-onset Alzheimer's disease and frontotemporal dementia neuroimaging signatures
Prior studies have described distinct patterns of brain gray matter and white matter alterations in Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD), as well as differences in their cerebrospinal fluid (CSF) biomarkers profiles. We aim to investigate the relationship between early‐onset AD (EOAD) and FTLD structural alterations and CSF biomarker levels. We included 138 subjects (64 EOAD, 26 FTLD, and 48 controls), all of them with a 3T MRI brain scan and CSF biomarkers available (the 42 amino acid‐long form of the amyloid‐beta protein [Aβ42], total‐tau protein [T‐tau], neurofilament light chain [NfL], neurogranin [Ng], and 14‐3‐3 levels). We used FreeSurfer and FSL to obtain cortical thickness (CTh) and fraction anisotropy (FA) maps. We studied group differences in CTh and FA and described the "AD signature" and "FTLD signature." We tested multiple regression models to find which CSF‐biomarkers better explained each disease neuroimaging signature. CTh and FA maps corresponding to the AD and FTLD signatures were in accordance with previous literature. Multiple regression analyses showed that the biomarkers that better explained CTh values within the AD signature were Aβ and 14‐3‐3; whereas NfL and 14‐3‐3 levels explained CTh values within the FTLD signature. Similarly, NfL levels explained FA values in the FTLD signature. Ng levels were not predictive in any of the models. Biochemical markers contribute differently to structural (CTh and FA) changes typical of AD and FTLD
Differential body composition effects of protease inhibitors recommended for initial treatment of HIV infection: A randomized clinical trial
This article has been accepted for publication in Clinical Infectious Diseases ©2014 The Authors .Published by Oxford University Press on Clinical Infectious Disease 60.5. DOI: 10.1093/cid/ciu898Background. It is unclear whether metabolic or body composition effects may differ between protease inhibitor-based regimens recommended for initial treatment of HIV infection.
Methods. ATADAR is a phase IV, open-label, multicenter randomized clinical trial. Stable antiretroviral-naive HIV-infected adults were randomly assigned to atazanavir/ritonavir 300/100 mg or darunavir/ritonavir 800/100 mg in combination with tenofovir/emtricitabine daily. Pre-defined end-points were treatment or virological failure, drug discontinuation due to adverse effects, and laboratory and body composition changes at 96 weeks.
Results. At 96 weeks, 56 (62%) atazanavir/ritonavir and 62 (71%) darunavir/ritonavir patients remained free of treatment failure (estimated difference 8.2%; 95%CI -0.6 to 21.6); and 71 (79%) atazanavir/ritonavir and 75 (85%) darunavir/ritonavir patients remained free of virological failure (estimated difference 6.3%; 95%CI -0.5 to 17.6). Seven vs. five patients discontinued atazanavir/ritonavir or darunavir/ritonavir due to adverse effects. Total and HDL cholesterol similarly increased in both arms, but triglycerides increased more in atazanavir/ritonavir arm. At 96 weeks, body fat (estimated difference 2862.2 gr; 95%CI 726.7 to 4997.7; P=0.0090), limb fat (estimated difference 1403.3 gr; 95%CI 388.4 to 2418.2; P=0.0071), and subcutaneous abdominal adipose tissue (estimated difference 28.4 cm2; 95%CI 1.9 to 55.0; P=0.0362) increased more in atazanavir/ritonavir than in darunavir/ritonavir arm. Body fat changes in atazanavir/ritonavir arm were associated with higher insulin resistance.
Conclusions. We found no major differences between atazanavir/ritonavir and darunavir/ritonavir in efficacy, clinically-relevant side effects, or plasma cholesterol fractions. However, atazanavir/ritonavir led to higher triglycerides and total and subcutaneous fat than darunavir/ritonavir and fat gains with atazanavir/ritonavir were associated with insulin resistanceThis is an Investigator Sponsored Research study. It was supported in part by research grants
from Bristol‐Myers Squibb and Janssen‐Cilag; Instituto de Salud Carlos III (PI12/01217) and Red
Temática Cooperativa de Investigación en SIDA G03/173 (RIS‐EST11), Ministerio de Ciencia e
Innovación, Spain. (Registration number: NCT01274780; registry name: ATADAR; EUDRACT; 2010‐021002‐38)
Experiències entrecreuades a Santa Eugènia del Congost
Rastres de memòria no escrita. D’experiències entrecreuades a Santa Eugènia del Congost... és el primer d’una sèrie de quaderns de treball amb mostres de material visual recollit en el marc del projecte artístic i didàctic Experiències entrecreuades a Santa Eugènia del Congost, desenvolupat en el context de l’antiga font i safareigs de Santa Eugènia del Congost –situats prop de l’autovia C-17, el riu Congost i de l’Ajuntament de Tagamanent–. Des del curs acadèmic 2016-2017, el Grup d’Innovació Docent Consolidat de la Universitat de Barcelona ATESI (Art, Territori, Estratègia Docent, Sostenibilitat i Intervenció Social – GINDC-UB/162) promou accions –instal·lacions artístiques efímeres, performance, tallers oberts, exposicions i actes...– per tal de «reviure» de forma física i conceptual aquests espais en desús per a la població, tot fent èmfasi en la recuperació de la seva memòria històrica, i amb una metodologia que busca integrar l’actuació conjunta d’administracions, figures expertes, centres educatius i ciutadanes. Aquestes accions, ideològicament posicionades, parteixen del treball en règim d’Aprenentatge Servei (ApS), una metodologia docent que implica l’assoliment de competències educatives en la realització d’activitats que tenen un retorn directe en la comunitat. En aquesta línia, les actuacions dutes a terme que es mostren en aquest quadern han tingut la participació d’alumnat del Grau en Belles Arts de la Universitat de Barcelona, de l’Escola Sagrats Cors de Centelles, de l’Escola d’Art i Superior de Disseny de Vic i d’ex-alumnes del mateix centre (EXARTVIC), coordinat per professorat dels diferents àmbits i amb la participació del Grup ApS(UB)
- …