Intermediate depth and deep earthquakes: complexity of the Ibero-Magrhebian region

The Ibero-Magrhebian region is located at the plate boundary between Eurasia and Africa and it is a tectonically complex region. A sign of the complexity, is the occurrence of intermediate depth earthquakes (40<h<150 km), located in south Spain, between Granada- Malaga and at the west part of Alboran Sea, together with the occurrence of very deep earthquakes (h≈650 km) near Dúrcal (Granada). Intermediate depth shocks are mostly confined within a relatively narrow region (50 km width) located East of Gibraltar, extending NNE-SSW from the Malaga (Spain) area to a region offshore the Moroccan coast. We have studied focal mechanisms of these earthquakes from inversion of body wave. The stress pattern in the Ibero-Maghrebian region obtained from solutions of selected shallow, intermediate depth and deep shocks show the complexity of the region. The seismotectonic scheme show horizontal compression in NNW-SSE direction in the Gulf of Cádiz. In northern Africa, the stress pattern changes and it corresponds to strike-slip motion, with extends from west of the Gibraltar Strait until the western Algeria, where in the Oran region the horizontal compression N-S reapers, with a clear domain of the thrusting faults in Algeria. In the Alboran Sea there is horizontal extension in E-W direction for shallow events. The intermediate depth shock located at the western part of the Alboran Sea show a change on the stress pattern: to the west of 4.5oW, focal mechanisms show vertical tension axis, while to the east, they show vertical pressure axis. These stress orientations are not present in deep earthquakes, where the pressure axes dip 45o to the east. The intermediate and deep earthquakes may be related to some kind of subduction or delamination processes, more recent for the intermediate depth shocks and older for the very deep activity

Kidins220/ARMS as a functional mediator of multiple receptor signalling pathways

An increasing body of evidence suggests that several membrane receptors – in addition to activating distinct signalling cascades – also engage in substantial crosstalk with each other, thereby adjusting their signalling outcome as a function of specific input information. However, little is known about the molecular mechanisms that control their coordination and integration of downstream signalling. A protein that is likely to have a role in this process is kinase-D-interacting substrate of 220 kDa [Kidins220, also known as ankyrin repeat-rich membrane spanning (ARMS), hereafter referred to as Kidins220/ARMS]. Kidins220/ARMS is a conserved membrane protein that is preferentially expressed in the nervous system and interacts with the microtubule and actin cytoskeleton. It interacts with neurotrophin, ephrin, vascular endothelial growth factor (VEGF) and glutamate receptors, and is a common downstream target of several trophic stimuli. Kidins220/ARMS is required for neuronal differentiation and survival, and its expression levels modulate synaptic plasticity. Kidins220/ARMS knockout mice show developmental defects mainly in the nervous and cardiovascular systems, suggesting a crucial role for this protein in modulating the cross talk between different signalling pathways. In this Commentary, we summarise existing knowledge regarding the physiological functions of Kidins220/ARMS, and highlight some interesting directions for future studies on the role of this protein in health and disease.This study was supported by research grants from: Cancer Research UK (to G.S.); the Italian Institute of Technology (to F.C. and F.B.); the Italian Ministry of University and Research [2008T4ZCNL grant number 2008T4ZCNL to F.B.]; the Compagnia di San Paolo, Torino (to F.B.); Telethon-Italy [grant number GGP09134 to F.B.] and the Spanish Ministry of Science and Innovation [grant number JCI-2008-01843 to V.N.].Peer reviewe

Modeling of the source mechanism of the April 5, 2003 paroxysmal eruption at Stromboli volcano (Italy) by the inversion of broadband seismic data

Abstract: On April 5, 2003, one of the largest eruptions in the last decades was observed at Stromboli volcano, Italy. The eruption occurred in a period of anomalous volcanic activity, after a previous explosion in December 2002 interrupted the typical moderate "Strombolian" behaviour. An exhaustive analysis of the available broadband seismic data is here presented and related to the observed eruption phases. Prominent features of the seismic signals include a very long period signal a few tens of seconds prior to the explosive eruption, as well as a strong energetic signal a few seconds after the onset of the eruption

Influence of topograhy on the seismic waveforms associated to eruptive events at Stromboli volcano

The steep topography, which characterizes certain volcanic areas, may strongly influence the displacement field associated to seismic signals. As a consequence, the interpretation of seismic data for the inversion of the seismic source and the crustal structure properties should carefully take into account these effects. We propose a set of numerical simulations for seismic wave propagation in a 3-D homogeneous model of Stromboli volcano, Italy, based on the application of a pseudospectral technique. The model assumes a topography with a discretization of 100 m on the horizontal directions, and 1 m on the vertical direction, while bathymetry is not yet included. We estimate the surface displacement field for different seismic sources, reproducing possible phenomena occurring during an eruptive process. These include purely isotropic sources, the realistic inclusion of an additional deviatoric CLVD component, which may take into account the effects of explosive events in presence of conduits and the final fall-out of material at the volcanic surface. Different durations of the source time function are tested in order to compare the effects of topography for seismic radiations with a variable range of frequency content. The comparison of results highlights the effects, which are strictly related to the presence of a steep topography

Effect of Prosopis flexuosa on understory species and its importance to pastoral management in woodlands of the Central Monte Desert

In the Monte Biogeographic Province, located in the arid region of Argentina, the presence of Prosopis flexuosa DC. produces spatial heterogeneity through edaphic modifications and microclimate changes. This results in vegetation patches differing in species composition and abundance. However, this interaction can be modified by the occurrence of gradients of biotic stress or disturbance intensity. In particular, grazing has been observed to enhance or reduce vegetation heterogeneity. Such complex of interactions could determine forage availability for cattle in one of the driest areas of the Monte Desert. We assessed the effect of Prosopis on understory species and analyzed whether the outcomes of this interaction differed with distance to watering points, as a proxy of grazing intensity, in the Northeast of Mendoza Province, Argentina. We used a two-way factorial design including the following factors: 1) microsite (under the cover of P. flexuosa trees and in intercanopy microsites) and 2) distance to watering points ("near the watering point", 500-700 m away, and "far from the watering point", 3-4 km away). Cover of each species, total cover, bare soil, and litter were recorded, and plant diversity, richness, and evenness were estimated with the modified Point Quadrat method. Results showed that P. flexuosa cover, distance from watering points, and the interaction between them determined species composition, abundance and spatial distribution of understory species, and were, consequently, a determining factor for forage availability. The presence of P. flexuosa enhances carrying capacity by supporting higher abundance of grasses under its canopy. Near watering points, high grazing intensity appears to disrupt the patches formed under P. flexuosa canopies, reducing the differences between microsites.In the Monte Biogeographic Province, located in the arid region of Argentina, the presence of Prosopis flexuosa DC. produces spatial heterogeneity through edaphic modifications and microclimate changes. This results in vegetation patches differing in species composition and abundance. However, this interaction can be modified by the occurrence of gradients of biotic stress or disturbance intensity. In particular, grazing has been observed to enhance or reduce vegetation heterogeneity. Such complex of interactions could determine forage availability for cattle in one of the driest areas of the Monte Desert. We assessed the effect of Prosopis on understory species and analyzed whether the outcomes of this interaction differed with distance to watering points, as a proxy of grazing intensity, in the Northeast of Mendoza Province, Argentina. We used a two-way factorial design including the following factors: 1) microsite (under the cover of P. flexuosa trees and in intercanopy microsites) and 2) distance to watering points ("near the watering point", 500-700 m away, and "far from the watering point", 3-4 km away). Cover of each species, total cover, bare soil, and litter were recorded, and plant diversity, richness, and evenness were estimated with the modified Point Quadrat method. Results showed that P. flexuosa cover, distance from watering points, and the interaction between them determined species composition, abundance and spatial distribution of understory species, and were, consequently, a determining factor for forage availability. The presence of P. flexuosa enhances carrying capacity by supporting higher abundance of grasses under its canopy. Near watering points, high grazing intensity appears to disrupt the patches formed under P. flexuosa canopies, reducing the differences between microsites

Source inversion of seismic events recorded in the Larderello geothermal area

The Larderello geothermal field is a wide thermal anomaly located in the western part of Tuscany (Italy). Geophysical investigations in this area suggest a crustal thinning and intrusion of hot mantle material into the crust. The local seismicity, monitored since 1978 by a network of 26 short period almost vertical seismic stations, is characterized by a several hundred of M 1.5 events per year, never exceeding M=3.2 in the past 25 years. At December 2004 ENEL and INGV started a scientific collaboration, which includes also exchange of selected datasets. One of the main tasks is to perform source inversion of low magnitude seismic events recorded in the Larderello geothermal area. This is of particular interest, because such earthquakes could show similarities with seismic events recorded on active volcanoes. In order to record also seismic events below magnitude M = 1 the gain of the ENEL-seismic network is set rather sensitive. This implicates that seismograms of events with magnitudes M > 2.0 are recorded by the entire network, but at low epicentral distances the traces are often saturated, making a waveform inversion impossible. On the other hand, smaller events are not strong enough to be recorded also at the more external stations of the network. In both cases this trade-off results in a limited number of vertical component recordings available for the inversion. A further difficulty by performing source inversion of small seismic events is to fit the high frequencies. Therefore we applied the moment tensor (MT) inversion both in the time domain as well as in the frequency domain and compared the results. Source inversion was performed both for the full MT as well as by introducing constraints for doubles couple e/o CLVD. The source inversions of events occurred in the Travale area show a high double couple percentage and show no indications for an isotropic source. This seems to indicate a source mechanism which is typical for tectonic events

Mild Inactivation of RE-1 Silencing Transcription Factor (REST) Reduces Susceptibility to Kainic Acid-Induced Seizures

RE-1 Silencing Transcription factor (REST) controls several steps in neural development by modulating the expression of a wide range of neural genes. Alterations in REST expression have been associated with the onset of epilepsy; however, whether such alterations are deleterious or represent a protective homeostatic response remains elusive. To study the impact of REST modulation on seizure propensity, we developed a tool for its negative modulation in vivo. The tool is composed of the paired-amphipathic helix 1 (PAH1) domain, a competitive inhibitor of REST activation by mSin3, fused to the light-oxygen-voltage sensing 2 (LOV2) domain of Avena sativa phototropin 1, a molecular switch to alternatively hide or expose the PAH1 inhibitor. We employed the C450A and I539E light-independent AsLOV2 variants to mimic the closed (inactive) and open (active) states of LOV2-PAH1, respectively. Recombinant AAV1/2 viral particles (rAAVs) allowed LOV2-PAH1 expression in HEK293T cells and primary neurons, and efficiently transduced hippocampal neurons in vivo. mRNA expression analysis revealed an increased expression of several neuronal genes in the hippocampi of mice expressing the open probe. AAV-transduced mice received a single dose of kainic acid (KA), a treatment known to induce a transient increase of REST levels in the hippocampus. Remarkably, mice expressing the active variant displayed a reduced number of KA-induced seizures, which were less severe compared to mice carrying the inactive probe. These data support the validity of our tool to modulate REST activity in vivo and the potential impact of REST modulation on epileptogenesis

Control of Au nanoantenna emission enhancement of magnetic dipolar emitters by means of VO2 phase change layers

Active, ultra-fast external control of the emission properties at the nanoscale is of great interest for chip-scale, tunable and efficient nanophotonics. Here we investigated the emission control of dipolar emitters coupled to a nanostructure made of an Au nanoantenna, and a thin vanadium dioxide (VO2) layer that changes from semiconductor to metallic state. If the emitters are sandwiched between the nanoantenna and the VO2 layer, the enhancement and/or suppression of the nanostructure’s magnetic dipole resonance enabled by the phase change behavior of the VO2 layer can provide a high contrast ratio of the emission efficiency. We show that a single nanoantenna can provide high magnetic field in the emission layer when VO2 is metallic, leading to high emission of the magnetic dipoles; this emission is then lowered when VO2 switches back to semiconductor. We finally optimized the contrast ratio by considering different orientation, distribution and nature of the dipoles, as well as the influence of a periodic Au nanoantenna pattern. As an example of a possible application, the design is optimized for the active control of an Er3+ doped SiO2 emission layer. The combination of the emission efficiency increase due to the plasmonic nanoantenna resonances and the ultra-fast contrast control due to the phase-changing medium can have important applications in tunable efficient light sources and their nanoscale integration

SURGERY IN MALIGNANT GERM CELL TUMORS OF CHILDHOOD. RESULTS OF THE SECOND ITALIAN COOPERATIVE STUDY TCG 98

Analysis of treatment and results of the patientsenrolled in the Italian TCG-98 Study, still open and comparison of data with those of the previous Studt TCG-9