616 research outputs found
Avance de los resultados obtenidos mediante datación isotópica de algunos espeleotemas subacuáticos mallorquines
[eng] Speleothems from two coastal caves in Mallorca (Spain) have been dated by means of the 230Th / 234 U method. The results obtained confirm a speleomorphological interpretation previously established by some of the authors. Two of the samples are very close to the limits of these dating techniques (more than 300 Ka) and at the same time the position of both speleothems (at an elevation of aproximately 30 metres above sea level) correlates well with a Paleotirrenian age, according to the speleomorphological interpretation.[cat] Alguns espeleotemes procedents de dues coves costeres de Mallorca han estat datats mitjançant el mètode Th 230 /U 234. Els resultats obtenguts tenden a confirmar el model espeleomorfològic establert prèviament per alguns dels autors. Dues de les mostres es troben molt a prop dels límits de resolució vàlids per aquesta tècnica de datació (més de 300.000 anys), al temps que la posició de ambdos espeleotemes (a més de 30 metres d'altura per damunt el nivell de la mar) se correlaciona bé amb una edat paleotirreniana, coincidint així amb el model espeleomorfològic
El registre paleontològic de l’illa d’Eivissa a jaciments litorals pleistocens
[cat] Es presenta des d’una visió històrica, l’estudi del registre paleontològic del Pleistocè de l’illa d’Eivissa, des dels seus inicis a finals del segle XIX fins l’actualitat, per després comentar els jaciments de platja i els que contenen fòssils continentals. Els primers són escassos per la qual cosa hi ha un registre baix de tàxons marins. Els jaciments d’origen continental són nombrosos i el registre paleontològic es caracteritza per a presentar mol·luscs endèmics (Tudorella ferruginea) i en alguns indrets traces fòssils d’insecte (i.e. Rebuffoichonus casamiquelai).[eng] This article gives a historical view of the Pleistocene on the island of Ibiza, from its beginnings in the late nineteenth century to the present. Then, beach deposits are synthetically described focusing on paleontological content and finally, the deposits that contain continental fauna. The first ones are scarce, for this reason there is a few marine taxa registers. Moreover, there are a high number of continental deposits and their paleontological data is characterized by endemic Mollusca and in some sites there are insect traces
Endocarditis trombótica no bacteriana (Libman-Sacks)
Mujer de 47 años ingresada en 2002 por ictus. Se diagnosticó masa valvular aórtica. Se intervino realizándose exéresis de trombo no bacteriano (Fig 1a, b). Durante el estudio de trombofilia fue diagnosticada de síndrome antifosfolípido primario (SAP), inciándose anticoagulación. Hasta la fecha, ha padecido múltiples accidentes cerebrovasculares, isquémicos y hemorrágicos. Está en diálisis peritoneal con probable origen en SAP. SAP es un trastorno autoinmune caracterizado por fenómenos trombóticos iterativos y alargamiento de tiempos de coagulación. La cirugía cardiaca conlleva morbimortalidad por tromboembolias, suponiendo un reto en el manejo de la circulación extracorpórea. Las complicaciones tromboembólicas son frecuentes durante el seguimiento.A 47-year-old woman was admitted in 2002 due to stroke. An aortic valve mass was diagnosed and surgical removal of non-bacterial thrombus performed (Fig. 1a, b). During the study for thrombophilia, primary antiphospholipidic syndrome (PSA) was diagnosed and oral anticoagulation started. Up to date, she presented with multiple episodes of cerebrovascular accident, ischemic and hemorrhagic. She is on peritoneal dialysis. PAS is an autoimmune disorder characterized by recurrent thrombotic phenomena and prolonged coagulation time. Cardiac surgery carries morbidity and mortality due to thromboembolic events, representing a challenge in the management of extracorporeal circulation. Thromboembolic complications are frequent during the follow-up
Effective nonlinear Ehrenfest hybrid quantum-classical dynamics
The definition of a consistent evolution equation for statistical hybrid
quantum-classical systems is still an open problem. In this paper we analyze
the case of Ehrenfest dynamics on systems defined by a probability density and
identify the relations of the non-linearity of the dynamics with the
obstructions to define a consistent dynamics for the first quantum moment of
the distribution. This first quantum moment represents the physical states as a
family of classically-parametrized density matrices , for
a classical point; and it is the most common representation of hybrid systems
in the literature. Due to this obstruction, we consider higher order quantum
moments, and argue that only a finite number of them are physically measurable.
Because of this, we propose an effective solution for the hybrid dynamics
problem based on approximating the distribution by those moments and
representing the states by them.Comment: 21 pages. Minor correction in the list of affiliation
Prenatal Diagnosis of Gómez-López-Hernández Syndrome.
Gómez-López-Hernández syndrome (GLHS), also known as cerebello-trigeminal-dermal dysplasia, is an extremely rare neurocutaneous disease, classically described by the triad of rhombencephalosynapsis (RES), bilateral focal alopecia, and trigeminal anesthesia. The clinical and radiographic spectrum of GLHS is now known to be broader, including craniofacial and supratentorial anomalies, as well as neurodevelopmental issues.
Here, we present a case of antenatally diagnosed GLHS with RES, hydrocephaly, and craniofacial anomalies identified on ultrasound (low-set ears with posterior rotation, hypertelorism, midface hypoplasia, micrognathia, and anteverted nares) which were confirmed by autopsy after termination of pregnancy at 23 weeks of gestation.
As no known genetic causes have been identified and the classical triad is not applicable to prenatal imaging, prenatal diagnosis of GLHS is based on neuroimaging and the identification of supporting features. In presence of an RES associated with craniofacial abnormalities in prenatal (brachycephaly, turricephaly, low-set ears, midface retrusion, micrognathia), GLHS should be considered as "possible" according to postnatal criteria
Assessment of fetal corpus callosum biometry by 3D super-resolution reconstructed T2-weighted magnetic resonance imaging.
To assess the accuracy of corpus callosum (CC) biometry, including sub-segments, using 3D super-resolution fetal brain MRI (SR) compared to 2D or 3D ultrasound (US) and clinical low-resolution T2-weighted MRI (T2WS).
Fetal brain biometry was conducted by two observers on 57 subjects [21-35 weeks of gestational age (GA)], including 11 cases of partial CC agenesis. Measures were performed by a junior observer (obs1) on US, T2WS and SR and by a senior neuroradiologist (obs2) on T2WS and SR. CC biometric regression with GA was established. Statistical analysis assessed agreement within and between modalities and observers.
This study shows robust SR to US concordance across gestation, surpassing T2WS. In obs1, SR aligns with US, except for genu and CC length (CCL), enhancing splenium visibility. In obs2, SR closely corresponds to US, differing in rostrum and CCL. The anterior CC (rostrum and genu) exhibits higher variability. SR's regression aligns better with literature (US) for CCL, splenium and body than T2WS. SR is the method with the least missing values.
SR yields CC biometry akin to US (excluding anterior CC). Thanks to superior 3D visualization and better through plane spatial resolution, SR allows to perform CC biometry more frequently than T2WS
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