N=2 SUGRA BPS Multi-center solutions, quadratic prepotentials and Freudenthal transformations

We present a detailed description of N=2 stationary BPS multicenter black hole solutions for quadratic prepotentials with an arbitrary number of centers and scalar fields making a systematic use of the algebraic properties of the matrix of second derivatives of the prepotential, $\mathcal{S}$, which in this case is a scalar-independent matrix. In particular we obtain bounds on the physical parameter of the multicenter solution such as horizon areas and ADM mass. We discuss the possibility and convenience of setting up a basis of the symplectic vector space built from charge eigenvectors of the \ssigma, the set of vectors (\Ppm q_a) with \Ppm \ssigma-eigenspace proyectors. The anti-involution matrix $\mathcal{S}$ can be understood as a Freudenthal duality \tilde{x}=\ssigma x. We show that this duality can be generalized to "Freudenthal transformations" x\to \lambda\exp(\theta \ssigma) x= a x+b\tilde{x} under which the horizon area, ADM mass and intercenter distances scale up leaving constant the fix point scalars. In the special case $\lambda=1$, "\ssigma-rotations", the transformations leave invariant the solution. The standard Freudental duality can be written as \tilde x= \exp(\pi/2 \ssigma) x . We argue that these generalized transformations leave also invariant the general stringy extremal quartic form $\Delta_4$, $\Delta_4(x)= \Delta_4(\cos\theta x+\sin\theta\tilde{x})$.Comment: Latex 27 pages (11pt). Some modifications introduced. Minor misprints corrected. References adde

N=2 SUGRA BPS multi-center black holes and freudenthal triple systems

We present a detailed description of N = 2 stationary BPS multicenter black hole solutions for quadratic prepotentials with an arbitrary number of centers and scalar fields making a systematic use of the algebraic properties of the matrix of second derivatives of the prepotential, S, which in this case is a scalar-independent matrix. The anti-involution matrix S can be understood as a Freudenthal duality x̃ = Sx. We show that this duality can be generalized to “Freudenthal transformations”

Long-range repulsive interaction between TTF molecules on a metal surface induced by charge transfer

The low-coverage adsorption of a molecular electron donor, tetrathiafulvalene, on Au(111) is characterized by the spontaneous formation of superlattice of monomers, whose spacing exceeds the equilibrium distance of non-covalent interactions and depends on coverage. The origin of this peculiar growth mode is due to a long-range repulsive interaction between molecules. The analysis of molecular-pair distributions obtained by scanning tunneling microscopy measurements permits us to determine that the nature of TTF intermolecular interactions on Au (111) is electrostatic. A repulsion between molecules is caused by the accumulation of charge due to electron donation into the metal surface, as pictured through density functional theory calculations

Ferromagnetic coupling of mononuclear Fe centers in a self-assembled metal-organic network on Au(111)

The magnetic state and magnetic coupling of individual atoms in nanoscale structures relies on a delicate balance between different interactions with the atomic-scale surrounding. Using scanning tunneling microscopy, we resolve the self-assembled formation of highly ordered bilayer structures of Fe atoms and organic linker molecules (T4PT) when deposited on a Au(111) surface. The Fe atoms are encaged in a three-dimensional coordination motif by three T4PT molecules in the surface plane and an additional T4PT unit on top. Within this crystal field, the Fe atoms retain a magnetic ground state with easy-axis anisotropy, as evidenced by X-ray absorption spectroscopy and X-ray magnetic circular dichroism. The magnetization curves reveal the existence of ferromagnetic coupling between the Fe centers

Coexistence of calc-alkaline and ultrapotassic alkaline magmas at Mounts Cimini : evidence for transition from the Tuscan to the Roman Magmatic Provinces (central Italy)

The volcanic complex of Mts. Cimini (~0.90-1.30Ma) represents the geographical and chronological transition between the Tuscan Magmatic Province (TMP) and the Roman Magmatic Province (RMP), in central Italy. Major and trace elements, and Sr, Nd and Pb isotopes of whole-rock, as well as mineral chemistry analyses, were carried out on samples representative of the different petrographic and chronological units of Mts. Cimini. In particular, we focused on the olivine-bearing latites of Mts. Cimini that are the most mafic magmas, belong to the last phase of this volcanic activity, and are heterogeneous in highly incompatible element ratios and Sr-isotope compositions. We suggest that such heterogeneity reflects the occurrence of a heterogeneous upper mantle beneath central Italy, in which different portions, e.g., the sources of both the TMP and RMP, are characterized by distinct geochemical and petrographic features. In this scenario, about 900ka ago, the olivine-bearing latites mark the progressive decline of the TMP magma production in favour of partial melting of the RMP mantle region, thus recording the coexistence of both ultrapotassic alkaline and calc-alkaline magmas in the same volcanic region

Tackling CD147 exosome-based cell-cell signaling by electrochemical biosensing for early colorectal cancer detection

The great opportunities represented by exosomes in liquid biopsy diagnostics and the relevance of CD147 protein as diagnostic and prognostic cancer biomarker led us to develop the first bio-electroanalytical platform for the determination of exosomal CD147 (exoCD147) by exploiting micro-sized magnetic beads coated with specific anti-CD147 antibodies. The captured exosomal target protein was sandwiched by specific biotin functionalized detector antibodies followed by attaching streptavidin-HRP conjugate to perform the amperometric reading using screen-printed carbon electrodes (SPCEs) as electrode transducers in the presence of hydroquinone (HQ) and H2O2. The analytical and operational characteristics achieved by implementing this simple methodology allowed the sensitive (LOD 29 pg mL-1) and selective determination of CD147 and the analysis of exoCD147 in different but inter-related real clinical scenarios including lysed and entire exosomes previously isolated from CRC cell lines with different metastatic potential. The obtained results, in agreement with those provided by ELISA and WB, proved the reliability of the developed immunosensor and its potential to isolate or identify specific subpopulations of exosomes based on the differential expression of characteristic surface biomarkers.The financial support of PID2019-103899RB-I00 (Spanish Ministerio de Ciencia e Innovación) Research Project and the TRANSNANOAVANSENS-CM Program from the Comunidad de Madrid (Grant S2018/NMT-4349) are gratefully acknowledged. R.B. acknowledges the financial support of PI20CIII/00019 grant from the AES-ISCIII program. A.M-C. acknowledges a FPU predoctoral contract supported by the Spanish Ministerio de Educación, Cultura y Deporte.S

Caracterización petrológica y geoquímica del moteado leucocrático en rocas basálticas alcalinas.

La presencia de un moteado leucocrático en basaltos alcalinos es un aspecto bastante frecuente en este tipo de lavas. A pesar de ello los estudios sobre su origen e implicaciones son hoy en día escasos y controvertidos. Es por ello que en el presente trabajo se presenta un estudio detallado del moteado en el que se incluyen relaciones de campo así como una caracterización textural, mineralógica y geoquímica de una selección de muestras. Los resultados obtenidos permiten sugerir que el moteado leucocrático se desarrolla como consecuencia del remplazamiento postmagmático de leucita primaria intersticial, dispuesta en forma de cuerpos poiquilíticos, por analcima secundaria. El aumento de volumen que supone este remplazamiento explica el mayor grado de fracturación de los minerales esenciales (olivino, clinopiroxeno y plagioclasa) así como la formación de grietas capilares que se disponen de forma radial desde los motes y que pueden llegar a comprometer la coherencia de la roca. Las observaciones realizadas indican que el desarrollo y tipología de moteado están fuertemente condicionados por la temperatura de la roca y la presencia de agua. Palabras clave: moteado leucocrático, basaltos alcalinos, analcimitización, leucita poiquilítica intersticial. /// The presence of sunburns is a common feature in alkaline basaltic rocks. Despite their frequent occurrence, works that have studied the origin and implications of sunburn presence are still scarce and controversial. In this study we present a detailed work on sunburns including field relations and a textural, mineralogical and geochemical characterization of a set of selected samples. The obtained results evidence that leucocratic discolorations are developed as a consequence of post-magmatic replacement of primary interstitial groundmass leucite arranged in poikilitic bodies by secondary analcime. The volume increase associated to this replacement explains the major degree of fracturing of the framework minerals (olivine, clinopyroxene and plagioclase) as well as the development of radial capillary cracks that radiate outwards from the sunburns. Both characteristics can compromise the coherence of the rock. Al the observations indicate that the combination of rock temperature and water supply strongly conditions de development and type of sunburns

Book review

Teresa MORENO and Wes GIBBONS (eds.), The Geology of Chile. London: Geological Society, 2007