113 research outputs found
Stress states and moment rates of a two-asperity fault in the presence of viscoelastic relaxation
Abstract. A fault containing two asperities with different strengths is considered. The fault is embedded in a shear zone subject to a constant strain rate by the motions of adjacent tectonic plates. The fault is modelled as a discrete dynamical system where the average values of stress, friction and slip on each asperity are considered. The state of the fault is described by three variables: the slip deficits of the asperities and the viscoelastic deformation. The system has four dynamic modes, for which analytical solutions are calculated. The relationship between the state of the fault before a seismic event and the sequence of slipping modes in the event is enlightened. Since the moment rate depends on the number and sequence of slipping modes, the knowledge of the source function of an earthquake constrains the orbit of the system in the phase space. If the source functions of a larger number of consecutive earthquakes were known, the orbit could be constrained more and more and its evolution could be predicted with a smaller uncertainty. The model is applied to the 1964 Alaska earthquake, which was the effect of the failure of two asperities and for which a remarkable post-seismic relaxation has been observed in the subsequent decades. The evolution of the system after the 1964 event depends on the state from which the event was originated, that is constrained by the observed moment rate. The possible durations of the interseismic interval and the possible moment rates of the next earthquake are calculated as functions of the initial state
Un guijarro contra la barbarie : presentación de Poesía y violencia
Presentazione del numero monografico della rivista Tintas. Quaderni di Letterature Iberiche e Iberoamericane dedicato al tema "Poesia e Violenza
RepeatsDB in 2021: Improved data and extended classification for protein tandem repeat structures
The RepeatsDB database (URL: https://repeatsdb.org/) provides annotations and classification for protein tandem repeat structures from the Protein Data Bank (PDB). Protein tandem repeats are ubiquitous in all branches of the tree of life. The accumulation of solved repeat structures provides new possibilities for classification and detection, but also increasing the need for annotation. Here we present RepeatsDB 3.0, which addresses these challenges and presents an extended classification scheme. The major conceptual change compared to the previous version is the hierarchical classification combining top levels based solely on structural similarity (Class > Topology > Fold) with two new levels (Clan > Family) requiring sequence similarity and describing repeat motifs in collaboration with Pfam. Data growth has been addressed with improved mechanisms for browsing the classification hierarchy. A new UniProt-centric view unifies the increasingly frequent annotation of structures from identical or similar sequences. This update of RepeatsDB aligns with our commitment to develop a resource that extracts, organizes and distributes specialized information on tandem repeat protein structures.Fil: Paladin, Lisanna. UniversitĂ di Padova; ItaliaFil: Bevilacqua, Martina. UniversitĂ di Padova; ItaliaFil: Errigo, Sara. UniversitĂ di Padova; ItaliaFil: Piovesan, Damiano. UniversitĂ di Padova; ItaliaFil: MiÄŤetić, Ivan. UniversitĂ di Padova; ItaliaFil: Necci, Marco. UniversitĂ di Padova; ItaliaFil: Monzon, Alexander Miguel. UniversitĂ di Padova; ItaliaFil: Fabre, Maria Laura. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de BiotecnologĂa y BiologĂa Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de BiotecnologĂa y BiologĂa Molecular; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias BiolĂłgicas; ArgentinaFil: LĂłpez, JosĂ© Luis. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de BiotecnologĂa y BiologĂa Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de BiotecnologĂa y BiologĂa Molecular; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias BiolĂłgicas; ArgentinaFil: Nilsson, Juliet Fernanda. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de BiotecnologĂa y BiologĂa Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de BiotecnologĂa y BiologĂa Molecular; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias BiolĂłgicas; ArgentinaFil: RĂos, Javier Sebastián. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa; ArgentinaFil: Lorenzano Menna, Pablo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa; ArgentinaFil: Cabrera, Maia Diana Eliana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa; ArgentinaFil: González BuitrĂłn, MartĂn. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa; ArgentinaFil: Gonçalves Kulik, Mariane. Johannes Gutenberg Universitat Mainz; AlemaniaFil: Fernández Alberti, Sebastián. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa; ArgentinaFil: Fornasari, Maria Silvina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa; ArgentinaFil: Parisi, Gustavo Daniel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y TecnologĂa; ArgentinaFil: Lagares, Antonio. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de BiotecnologĂa y BiologĂa Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de BiotecnologĂa y BiologĂa Molecular; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias BiolĂłgicas; ArgentinaFil: Hirsh, Layla. Pontificia Universidad CatĂłlica de PerĂş; PerĂşFil: Andrade Navarro, Miguel A.. Johannes Gutenberg Universitat Mainz; AlemaniaFil: Kajava, Andrey V. Centre National de la Recherche Scientifique; FranciaFil: Tosatto, Silvio C E. UniversitĂ di Padova; Itali
RepeatsDB in 2021: improved data and extended classification for protein tandem repeat structures
The RepeatsDB database (URL: https://repeatsdb.org/) provides annotations and classification for protein tandem repeat structures from the Protein Data Bank (PDB). Protein tandem repeats are ubiquitous in all branches of the tree of life. The accumulation of solved repeat structures provides new possibilities for classification and detection, but also increasing the need for annotation. Here we present RepeatsDB 3.0, which addresses these challenges and presents an extended classification scheme. The major conceptual change compared to the previous version is the hierarchical classification combining top levels based solely on structural similarity (Class > Topology > Fold) with two new levels (Clan > Family) requiring sequence similarity and describing repeat motifs in collaboration with Pfam. Data growth has been addressed with improved mechanisms for browsing the classification hierarchy. A new UniProt-centric view unifies the increasingly frequent annotation of structures from identical or similar sequences. This update of RepeatsDB aligns with our commitment to develop a resource that extracts, organizes and distributes specialized information on tandem repeat protein structures.Facultad de Ciencias ExactasInstituto de Biotecnologia y Biologia Molecula
Paramedic Acute Stroke Treatment Assessment (PASTA): study protocol for a randomised controlled trial
BACKGROUND: Despite evidence from clinical trials that intravenous (IV) thrombolysis is a cost-effective treatment for selected acute ischaemic stroke patients, there remain large variations in the rate of IV thrombolysis delivery between stroke services. This study is evaluating whether an enhanced care pathway delivered by paramedics (the Paramedic Acute Stroke Treatment Assessment (PASTA)) could increase the number of patients who receive IV thrombolysis treatment. METHODS: Study design: Cluster randomised trial with economic analysis and parallel process evaluation. SETTING: National Health Service ambulance services, emergency departments and hyper-acute stroke units within three geographical regions of England and Wales. Randomisation: Ambulance stations within each region are the units of randomisation. According to station allocation, paramedics based at a station deliver the PASTA pathway (intervention) or continue with standard stroke care (control). Study intervention: The PASTA pathway includes structured pre-hospital information collection, prompted pre-notification, structured handover of information in hospital and assistance with simple tasks during the initial hospital assessment. Study-trained intervention group paramedics deliver this pathway to adults within 4 h of suspected stroke onset. Study control: Standard stroke care according to national and local guidelines for the pre-hospital and hospital assessment of suspected stroke. PARTICIPANTS: Participants enrolled in the study are adults with confirmed stroke who were assessed by a study paramedic within 4 h of symptom onset. PRIMARY OUTCOME: Proportion of participants receiving IV thrombolysis. SAMPLE SIZE: 1297 participants provide 90% power to detect a 10% difference in the proportion of patients receiving IV thrombolysis. DISCUSSION: The results from this trial will determine whether an enhanced care pathway delivered by paramedics can increase thrombolysis delivery rates. TRIAL REGISTRATION: ISRCTN registry, ISRCTN12418919 . Registered on 5 November 2015
Poesía y violencia
Numero monografico dedicato allla relazione tra poesia e violenza nel contesto della letteratura ispanoamericana. Oltre a tredici saggi critici prodotti da alcuni dei maggiori specialisti nel settore, il volume riunisce un'antologia di testi inediti di ventdiue poeti latinoamericani
Stress states and moment rates of a two-asperity fault in the presence of viscoelastic relaxation
A fault containing two asperities with different strengths is considered. The
fault is embedded in a shear zone subject to a constant strain rate by the
motions of adjacent tectonic plates. The fault is modelled as a discrete
dynamical system where the average values of stress, friction and slip on
each asperity are considered. The state of the fault is described by three
variables: the slip deficits of the asperities and the viscoelastic
deformation. The system has four dynamic modes, for which analytical
solutions are calculated. The relationship between the state of the fault
before a seismic event and the sequence of slipping modes in the event is
enlightened. Since the moment rate depends on the number and sequence of
slipping modes, the knowledge of the source function of an earthquake
constrains the orbit of the system in the phase space. If the source
functions of a larger number of consecutive earthquakes were known, the orbit
could be constrained more and more and its evolution could be predicted with
a smaller uncertainty. The model is applied to the 1964 Alaska earthquake,
which was the effect of the failure of two asperities and for which a
remarkable post-seismic relaxation has been observed in the subsequent
decades. The evolution of the system after the 1964 event depends on the
state from which the event was originated, that is constrained by the
observed moment rate. The possible durations of the interseismic interval and
the possible moment rates of the next earthquake are calculated as functions
of the initial state
Conditions for the occurrence of seismic sequences in a fault system
We consider a fault system producing a sequence of seismic events of similar
magnitudes. If the system is made up of n faults, there are n! possible
sequences, differing from each other for the order of fault activation.
Therefore the order of events in a sequence can be expressed as a permutation
of the first n integers. We investigate the conditions for the occurrence
of a seismic sequence and how the order of events is related to the initial
stress state of the fault system. To this aim, we consider n coplanar
faults placed in an elastic half-space and subject to a constant and uniform
strain rate by tectonic motions. We describe the state of the system by n
variables that are the Coulomb stresses of the faults. If we order the faults
according to the magnitude of their Coulomb stresses, a permutation of the
first n integers can be associated with each state of the system. This
permutation changes whenever a fault produces a seismic event, so that the
evolution of the system can be described as a sequence of permutations. A
crucial role is played by the differences between Coulomb stresses of the
faults. The order of events implicit in the initial state is modified due to
changes in the differences between Coulomb stresses and to different stress
drops of the events. We find that the order of events is determined by the
initial stress state, the stress drops and the stress transfers associated
with each event. Therefore the model allows the retrieval of the stress
states of a fault system from the observation of the order of fault
activation in a seismic sequence. As an example, the model is applied to the
2012 Emilia (Italy) seismic sequence and enlightens the complex interplay
between the fault dislocations that produced the observed order of events
Intravenous thrombolysis with rt-PA in acute stroke patients aged >= 80 years
Intravenous thrombolysis with rt-PA within three hours of symptom onset is the only proven effective treatment for acute ischemic stroke. The European license limits the use of rt-PA to patients aged <80 years for the lack of clear evidence of safety and efficacy of this treatment in the elderly. © 2008 Bentham Science Publishers Ltd
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