34 research outputs found
Inversion of surface wave phase velocities in a slightly a nisotropic medium
Inversion of surface wave velocities in examples of multilayered anisotropic media is
examined using an extension of the Smith-Dahlen formulation. Thus, surface wave
propagation in a slightly anisotropic earth model has been found and the inversion of
the azimuthal dependence of surface wave dispersion curves has been performed.
The inversion scheme proposed in this paper has been verified by numerical matrix
inversion with a computer programme in FORTRAN code. In two examples,
hexagonal simmetry and 13 non zero canonical harmonic components, we have got
results that show an excellent agreement between all phase velocities obtained for
both Love and Rayleigh waves. We also perform two additional experiments with
observed data, Love and Rayleigh waves phase velocities results of previous studies
carry out in the Pacific (Nishimura & Forsyth, 1985, 1988, 1989). In these data test
we also have a good agreement between observed and theoretical data
Near surface velocity structure of Andalucia (Southern Spain) and alboran sea region from 0.15-2.0 HZ rayleigh waves
Una metodología que ha sido aplicada desde hace poco tiempo en Sismología, es el
modelado de estructuras muy superficiales a partir de la inversión de valores de dispersión
(velocidad de grupo de ondas Rg de corto periodo). Esto es posible, debido a que la
velocidad de grupo de las ondas Rg de corto periodo, es sensible a las variaciones en la
estructura de la velocidad de cizalla de las capas más superficiales de la corteza. En esta
línea, nosotros hemos emprendido el presente trabajo: la determinación de los modelos de
velocidad de cizalla para la región de Andalucía y mar de Alborán (sur de Iberia), por
medio de la inversión generalizada de curvas de dispersión correspondientes a ondas Rg
(ondas Rayleigh de periodo corto). Nosotros usamos técnicas de filtrado digital, las cuales
proporcionan una significativa mejora en la razón señal-ruido, ayudando a determinar un
modelo razonable para la velocidad de las ondas de cizalla. Las curvas de dispersión
obtenidas muestran la complejidad de la estructura media cruzada por las ondas en cada
trayectoria analizada. Nosotros hemos invertido las curvas de dispersión medias obtenidas
para cada trayecto analizado, con el objeto de obtener modelos teóricos de velocidad de
cizalla, de acuerdo con la teoría de la inversión generalizada. Los resultados obtenidos
muestran la existencia, en el área de estudio, de fuertes variaciones laterales en las
propiedades físicas de los materiales dentro de un rango de profundidad que va desde 0 a 5
km. Los valores más altos de velocidad corresponden a trayectos que cruzan las
estructuras más antiguas, mientras que los valores más bajos corresponden a trayectorias que cruzan las estructuras más recientes
Pembrolizumab as Consolidation Strategy in Patients with Multiple Myeloma: Results of the GEM-Pembresid Clinical Trial
PD1 expression in CD4+ and CD8+ T cells is increased after treatment in multiple myeloma patients with persistent disease. The GEM-Pembresid trial analyzed the efficacy and safety of pembrolizumab as consolidation in patients achieving at least very good partial response but with persistent measurable disease after first- or second-line treatment. Moreover, the characteristics of the immune system were investigated to identify potential biomarkers of response to pembrolizumab. One out of the 17 evaluable patients showed a decrease in the amount of M-protein, although a potential late effect of high-dose melphalan could not be ruled out. Fourteen adverse events were considered related to pembrolizumab, two of which (G3 diarrhea and G2 pneumonitis) prompted treatment discontinuation and all resolving without sequelae. Interestingly, pembrolizumab induced a decrease in the percentage of NK cells at cycle 3, due to the reduction of the circulating and adaptive subsets (0.615 vs. 0.43, p = 0.007; 1.12 vs. 0.86, p = 0.02). In the early progressors, a significantly lower expression of PD1 in CD8+ effector memory T cells (MFI 1327 vs. 926, p = 0.03) was observed. In conclusion, pembrolizumab used as consolidation monotherapy shows an acceptable toxicity profile but did not improve responses in this MM patient population. The trial was registered at clinicaltrials.gov with identifier NCT02636010 and with EUDRACT number 2015-003359-23.This study was funded by Fundación Ramón Areces (FRA 16/003). T.P. is supported by a grant from the AECC (INVES18043PAIN). This study received financial support from Merck Sharp & Dohme of Spain, a subsidiary of Merck & Co., Inc., Whitehouse Station, New Jersey, USA
Pembrolizumab as consolidation strategy in patients with multiple myeloma: Results of the GEM-Pembresid clinical trial
PD1 expression in CD4+ and CD8+ T cells is increased after treatment in multiple myeloma
patients with persistent disease. The GEM-Pembresid trial analyzed the efficacy and safety of
pembrolizumab as consolidation in patients achieving at least very good partial response but with
persistent measurable disease after first- or second-line treatment. Moreover, the characteristics of the
immune system were investigated to identify potential biomarkers of response to pembrolizumab.
One out of the 17 evaluable patients showed a decrease in the amount of M-protein, although a
potential late effect of high-dose melphalan could not be ruled out. Fourteen adverse events were
considered related to pembrolizumab, two of which (G3 diarrhea and G2 pneumonitis) prompted
treatment discontinuation and all resolving without sequelae. Interestingly, pembrolizumab induced
a decrease in the percentage of NK cells at cycle 3, due to the reduction of the circulating and adaptive
subsets (0.615 vs. 0.43, p = 0.007; 1.12 vs. 0.86, p = 0.02). In the early progressors, a significantly
lower expression of PD1 in CD8+ effector memory T cells (MFI 1327 vs. 926, p = 0.03) was observed.
In conclusion, pembrolizumab used as consolidation monotherapy shows an acceptable toxicity
profile but did not improve responses in this MM patient population. The trial was registered at
clinicaltrials.gov with identifier NCT02636010 and with EUDRACT number 2015-003359-23
Finite Fault Analysis and Near Field Dynamic Strains and Rotations due to the 11/05/2011 (Mw5.2) Lorca Earthquake, South-Eastern Spain
The 11/5/2011 Lorca, Spain earthquake (Mw5.2) and related seismicity produced
extensive damage in the town of Lorca and vicinity. During these earthquakes,
evidence of rotations and permanent deformations in structures were observed.
To analyze these aspects and study the source properties from the near field,
the displacement time histories were obtained including the static component at
Lorca station. Displacement time histories were computed by an appropriate
double time integration procedure of accelerograms. Using these data, the
foreshock and mainshock slip distributions were calculated by means of a
complete waveform kinematic inversion. To study the dynamic deformations, the
3D tensor of displacement gradients at Lorca station was first estimated by a
single station method. Using the finite fault inversion results and by means of
a first order finite difference approach, the dynamic deformations tensor at
surface was calculated at the recording site. In order to estimate the
distribution of the peak dynamic deformations, the calculation was extended to
the close neighboring area of the town. The possible influence of the
near-field deformations on the surface structures was analyzed.Comment: 29 pages, 8 figure
Shear-wave Velocity Structure of Greenland from Rayleigh-wave Analysis
The elastic structure beneath Greenland is shown by means of S-velocity maps for depths ranging from zero to 350 km, determined by the regionalization and inversion of Rayleigh-wave dispersion. The traces of 50 earthquakes, occurring from 1990 to 2011, have been used to obtain Rayleigh-wave dispersion data. These earthquakes were registered by 21 seismic station located in Greenland and the surrounding area. The dispersion curves were obtained for periods between 5 and 200 s, by digital filtering with a combination of MFT (Multiple Filter Technique) and TVF (Time Variable Filtering). Later, all seismic events (and some stations) were grouped to obtain a dispersion curve for each source-station path. These dispersion curves were regionalized and inverted according to the generalized inversion theory, to obtain shear-wave velocity models for a rectangular grid of 16x20 points. The shear-velocity structure obtained through this procedure is shown in the S-velocity maps plotted for several depths. These results agree well with the geology and other geophysical results previously obtained. The obtained S-velocity models suggest the existence of lateral and vertical heterogeneity. The zones with consolidated and old structures present greater S-velocity values than the other zones, although this difference can be very little or negligible in some case. Nevertheless, in the depth range of 15 to 45 km, the different Moho depths present in the study area generate the principal variation of S-velocity. A similar behaviour is found for the depth range from 80 to 230 km, in which the lithosphere-asthenosphere boundary (LAB) generates the principal variations of S-velocity. Finally, the new and interesting feature obtained in this study: the definition of the base of the asthenosphere (for the whole study area and for depths ranging from 130 to 280 km, respectively) should be highlighted.
Estructura de velocidad de cizalla de Groenlandia obtenida de análisis de onda Rayleigh
Resumen
La estructura elástica bajo Groenlandia es mostrada por medio de mapas de velocidad de onda para profundidades variando desde cero a 350 km, determinada por la regionalización e inversión de la dispersión de onda Rayleigh. Las trazas de 50 terremotos, ocurridos desde 1990 hasta 2011, han sido usados para obtener datos de dispersión de onda Rayleigh. Estos terremotos fueron registrados por 21 estaciones sísmicas localizadas en Groenlandia y el área circundante. Las curvas de dispersión fueron obtenidas para periodos entre 5 y 200 s, por filtrado digital con una combinación de MFT (Técnica de Filtrado Múltiple) y TVF (Filtrado en Tiempo Variable). Después, todos los eventos sísmicos (y algunas estaciones) fueron agrupados para obtener una curva de dispersión para cada trayecto fuente-estación. Estas curvas de dispersión fueron regionalizadas e invertidas de acuerdo con la teoría de la inversión generalizada, para obtener modelos de velocidad de cizalla para una rejilla rectangular de 16x20 puntos. La estructura de velocidad de cizalla obtenida a través de este procedimiento es mostrada in los mapas de velocidad de onda S representados para varias profundidades. Estos resultados muestran buen acuerdo con la geología y con otros resultados geofísicos obtenidos previamente. Los modelos de velocidad de onda S obtenidos sugieren la existencia de heterogeneidad lateral y vertical. Las zonas con estructuras antiguas y consolidadas presentan mayores valores de velocidad de onda S que las otras zonas, aunque esta diferencia puede ser muy pequeña o despreciable en algún caso. No obstante, en el rango de profundidad de 15 a 45 km, las diferentes profundidades del Moho presentes en el área de estudio generan la principal variación de velocidad de onda S. Un comportamiento similar es encontrado para el rango de profundidad desde 80 a 230 km, en el cual la frontera litosfera-astenosfera (LAB) genera las principales variaciones de velocidad de onda S. Finalmente, debería ser destacada la nueva e interesante característica obtenida en este estudio: la definición de la base de la astenosfera (para el área de estudio completa y para profundidades variando desde 130 a 280 km, respectivamente)
A methodology for the analysis of the rayleigh-wave ellipticity
In this paper, a comprehensive explanation of the analysis (filtering and inversion) of the Rayleigh-wave ellipticity is performed, and the use of this analysis to determine the local crustal structure beneath the recording station is described. This inversion problem and the necessary assumptions to solve are described in this paper, along with the methodology used to invert the Rayleigh-wave ellipticity. The results presented in this paper demostrate that the analysis (filtering and inversion) of the Rayleigh-wave ellipticity is a powerful tool, for studying the local structure of the crust beneath the recording station. Therefore, this type of analysis is very useful for studies of seismic risk and/or seismic design, because it provides local earth models in the range of crustal depths. ResumenEn este artículo, será realizada una explicación fácil de comprender del análisis (filtrado e inversión) de la elipticidad de la onda Rayleigh, así como, de su aplicación para determinar la estructura local bajo la estación de registro. Este problema de inversión y los necesarios supuestos para resolverlo, serán descritos en el artículo, juntamente con la metodología utilizada para invertir la elipticidad de la onda Rayleigh. Los resultados presentados en este artículo mostrarán que el análisis (filtrado e inversión) de la elipticidad de la onda Rayleigh es una poderosa herramienta, para estudiar la estructura local de la corteza terrestre bajo la estación de registro, siendo este tipo de análisis muy útil para estudios de riesgo y/o diseño sísmico, porque proporciona modelos de Tierra locales en el rango de profundidades corticales