Interpretación de anisotropías petrográficas en granitos ornamentales basada en la medida de la velocidad de las ondas P

The existence of a possible anisotropy, determined by the orientation of any mineral or by micro­crack network in granite rock, isn´t easily detected by the naked eye. Five granitic rocks from Galicia (Spain), namely Albero, Gris Alba, Gris Mondariz, Rosa Porriño and Traspielas, were characterized petrographically by means of textural and mineralogical studies, using optical polarizing microscopy, and fractographic studies were carried out under scanning electron microscopy. Longitudinal wave propagation velocity was measured in three orthogonal directions on cubic samples, oriented according to rift surface (known in quarry works like the preferential partition surface visible in the blocks). Vp was measured on dry and water saturated samples. All the dry samples showed an anisotropic behaviour of Vp. Models of microcrack network distribution and possible mineral grain orientation were developed based on the obtained data.La existencia de una posible anisotropía originada por orientación de minerales y/o redes de microfisuración en rocas graníticas no es fácilmente detectable a simple vista. Cinco rocas graníticas de Galicia, denominadas comercialmente Albero, gris Alba, gris Mondariz, rosa Porriño y Traspielas, se car­acterizaron petrográficamente, mediante estudios texturales y mineralógicos utilizando microscopía óptica de polarización, realizándose también estudios fractográficos bajo microscopía electrónica de barrido. Se midieron las velocidades de propagación de las ondas longitudinales (Vp) en tres direcciones ortogonales en muestras cúbicas orientadas según el rift (denominado así en cantería como la superficie preferente de partición). Vp se midió en muestras secas y saturadas. Todas las muestras secas mostraron un comportamiento anisótropo de Vp. A partir de los datos obtenidos se han interpretado las redes de distribución de microfisuras y la orientación de minerales

Grid tool integration within the eMinerals Project

In this article we describe the eMinerals mini grid, which is now running in production mode. Thisis an integration of both compute and data components, the former build upon Condor, PBS and thefunctionality of Globus v2, and the latter being based on the combined use of the Storage ResourceBroker and the CCLRC data portal. We describe how we have integrated the middleware components,and the different facilities provided to the users for submitting jobs within such an environment. We willalso describe additional functionality we found it necessary to provide ourselves

Excitation energy dependence of electron-phonon interaction in ZnO nanoparticles

Raman spectroscopic investigations are carried out on ZnO nanoparticles for various photon energies. Intensities of E1-LO and E2 modes exhibit large changes as the excitation energy varied from 2.41 to 3.815 eV, signifying substantially large contribution of Frohlich interaction to the Raman polarizability as compared to deformation potential close to the resonance. Relative strength of these two mechanisms is estimated for the first time in nanoparticles and compared with those in the bulk.Comment: 13 pages. 3 figures Journa

Endomembrane PtdIns(3,4,5)P3 activates the PI3K–Akt pathway

PKB/Akt activation is a common step in tumour growth, proliferation and survival. Akt activation is understood to occur at the plasma membrane of cells in response to growth factor stimulation and local production of the phosphoinositide lipid phosphatidylinositol (3,4,5)- trisphosphate [PtdIns(3,4,5)P3] following phosphoinositide 3-kinase (PI3K) activation. The metabolism and turnover of phosphoinositides is complex - they act as signalling molecules as well as structural components of biological membranes. The localisation and significance of internal pools of PtdIns(3,4,5)P3 has long been speculated upon. By using transfected and recombinant protein probes for PtdIns(3,4,5)P3, we show that PtdIns(3,4,5)P3 is enriched in the nuclear envelope and early endosomes. By exploiting an inducible dimerisation device to recruit Akt to these compartments, we demonstrate that Akt can be locally activated in a PtdIns(3,4,5)P3- dependent manner and has the potential to phosphorylate compartmentally localised downstream substrates. This could be an important mechanism to regulate Akt isoform substrate specificity or influence the timing and duration of PI3K pathway signalling. Defects in phosphoinositide metabolism and localisation are known to contribute to cancer, suggesting that interactions at subcellular compartments might be worthwhile targets for therapeutic intervention

Heraldic seizure

AbstractBackground: The term heraldic seizures indicates epileptic seizures caused by cerebrovascular disease, believed to be triggered by silent ischemia and occurring before a stroke. This fact widens the spectrum of possible interrelations between epilepsy and cerebrovascular disease outside the well known context of post-stroke epilepsy. Methods: This is a case report of a healthy 67-year-old male who had a new onset epileptic seizure prior to a lobar intracerebral hemorrhage (ICH). This man began to suffer myoclonic jerks in his left arm which progressed to a generalized tonic–clonic seizure. At the emergency area the physical and neurological examination were unremarkable and a CT scan was normal. The next day the patient developed left hemiparesis, hemianopsia and confusion and a new CT scan showed right parietal–occipital ICH. Conclusions: This case report exemplifies the concept of heraldic seizures, showing a patient who had a focal seizure preceding an intracerebral hemorrhage. Our etiologic diagnostic work led us to a diagnosis of probable amyloid angiopathy. We suggest that cerebral amyloid angiopathy (CAA) may be the underlying cause, since it may be the origin of both the late event (ICH) and the heralding seizures, resulting from concurrent ischemia

Bilateral Internuclear Ophthalmoplegia in a Young Woman with Vertebral Artery Dissection

Background: Internuclear ophthalmoplegia (INO) is an eye movement disorder caused by a lesion in the medial longitudinal fasciculus (MLF) located in the midbrain. Adduction paralysis of both eyes and bilateral abduction nystagmus are the main features of INO[1]. Case presentation: A 29-year-old Hispanic woman was admitted to the emergency department complaining of an intense holocranial headache lasting 9 days, associated with nausea and vomiting. She was discharged home with resolution of the headache but persistence of symptoms. However, she subsequently developed horizontal diplopia and gait abnormalities. She was readmitted to hospital because of anomalous eye movements and conjugate gaze palsy, manifested as bilateral INO. Magnetic resonance angiography (MRA) findings were consistent with dissection of the left V4 vertebral artery with multiple brain infarcts in the superior cerebellar artery territory, comprising both MLF tracts. Conclusions: In young adults, bilateral INO is normally caused by demyelinating disease. In other patients, common causes include trauma, infections and autoimmune diseases with neurological symptoms. Vascular disease is implicated in over a third of cases

Light emission and spin-polarised hole injection in InAs/GaAs quantum dot heterostructures with Schottky contact

EPL draftWe demonstrate the feasibility to obtain electroluminescence (EL), up to room temperature, from InGaAs self-assembled quantum dots (QDs) included in a forward-biased Schottky diode. Moreover, using a ferromagnet (FM) as the contact layer, sizable circular polarization of the EL emission in the presence of an external magnetic eld is obtained. A resonant behav- ior of the degree of circular polarization (P) as a function of applied voltage (V ), for a given value of magnetic eld, is observed. We explain our ndings using a model including tunneling of (spin-polarised) holes through the metal-semiconductor interface, transport in the near surface region of the heterostructure and out-of-equilibrium statistics of the injected carriers occupying the available states in the QD heterostructure. In particular, the resonant P(V ) dependence is related to the splitting of the qusi-Fermi level for two spin orientations in the FM.FCT, Portugal (project POCI/FIS/58524/2004), the RFBR, Russia (grant 10-02- 00501), MEC (grants MAT2008-01555, QOIT-CSD2006- 00019) and CAM (S-2009/ESP-1503) (Spain)

Change of direction deficit in national team rugby union players: is there an Influence of playing position?

The aim of this study was to investigate the change of direction (COD) ability and deficits of elite rugby union players, discriminating between position (backs and forwards), and between "faster and slower players", in multiple COD tasks. Twenty-four male rugby union players from the Brazilian senior National team completed the following assessments: Squat and countermovement jumps; drop jump; standing long jump, horizontal triple jumps; 40-m linear sprint; Pro-agility, L-Drill, and Zig-zag COD tests; and squat 1-repetition maximum. The differences between backs and forwards and between faster and slower performers were examined using magnitude-based inferences. Backs were faster (in both linear and COD speed tests) and jumped higher than forwards. Moreover, they generated an inferior sprint momentum. No differences were found in COD deficit between playing positions. However, when dividing the sample by median split, faster players outperformed their slower counterparts in all power⁻speed variables and presented higher COD deficits. These results suggest that separating rugby players by playing position might not discriminate players with different COD skills and that the median split analysis is more sensitive to identifying these differences. Furthermore, the present data indicate that faster rugby players are less efficient at changing direction and tolerating higher approach velocities in COD maneuvers

Ensayo de capilaridad en areniscas monitorizado mediante tomografía computerizada de rayos X. Estudio comparativo con métodos convencionales

Computerized axial tomography studies were conducted to analyze water movements inside rocks (specifically in La Marina sandstone, used to build some of the historic monuments in Asturias, northern Spain). The X-ray images of water uptake by the stone interior recorded during capillarity tests provided supplementary information not furnished by conventional methods. The three-dimensional images obtained showed the position of the water front over time and its relationship to rock petrography. The volume of water-soaked rock proved to be a more realistic measure of stone capillarity. The results obtained were compared to mean capillarity measured as recommended in Spanish and European standard UNE-EN 1925:1999.La Tomografía Axial Computerizada de rayos X (TAC) ha sido aplicada al estudio del movimiento del agua en el interior de las rocas, usando como modelo la arenisca de La Marina, roca utilizada en la construcción de algunos monumentos históricos en Asturias (norte de España). Durante los ensayos de capilaridad se han registrado las imágenes de rayos X de la penetración del agua en el interior de la roca que suministran información no aportada por los métodos habituales. La reconstrucción tridimensional muestra la posición del frente de agua a lo largo del tiempo y su relación con las características petrográficas de la roca. La cuantificación del porcentaje en volumen de roca embebida en agua es una medida más real de la capilaridad de la misma. Los resultados así obtenidos han sido comparados con los de la capilaridad medida por el método descrito en la norma UNE-EN 1925:1999