Experimental constraints on amphibole stability in primitive alkaline and calc-alkaline magmas

Equilibrium crystallization experiments were carried out on two primitive basaltic rocks (APR16: Na2O+K2O=4.40 wt%; CM42: Na2O+K2O=2.59 wt%) with the aim to investigate the amphibole stability in the differentiation processes at deep crustal level, of primitive alkaline (APR16) and calc-alkaline (CM42) magmas. The experiments were performed with different initial H2O contents (0-5 wt%), at pressure of 800 MPa, in the temperature range of 975-1225 °C. For the explored conditions, amphibole crystallization occurs in both compositions at H2O in the melt >7wt% while the temperature of their occurrence is lower in the alkaline composition (<1050 °C in APR16 and ≥1050 °C in CM42). Moreover, amphibole crystallization seems to be influenced by the Na2O/K2O ratio rather than the absolute Na2O content in the melt. This is evident when experimental results on the APR16 and CM42 are compared with experimental data obtained from a primitive ultrapotassic composition (leucite-basanite: Na2O+K2O=4.58 wt%) and with thermodynamic modelling by the Rhyolite-MELTS algorithm. The comparison shows that amphibole never saturates the leucite-basanite at any of the investigated/modelled conditions, even when an extended crystallization increases the Na2O of melts up to contents like those of calc-alkaline experimental glasses. We conclude that, at pressure of 800 MPa and hydrous conditions, only primitive liquids with Na2O/K2O ratio ≥0.9 are more prone to crystallize amphibole

Discrete phase-space approach to mutually orthogonal Latin squares

We show there is a natural connection between Latin squares and commutative sets of monomials defining geometric structures in finite phase-space of prime power dimensions. A complete set of such monomials defines a mutually unbiased basis (MUB) and may be associated with a complete set of mutually orthogonal Latin squares (MOLS). We translate some possible operations on the monomial sets into isomorphisms of Latin squares, and find a general form of permutations that map between Latin squares corresponding to unitarily equivalent mutually unbiased sets. We extend this result to a conjecture: MOLS associated to unitarily equivalent MUBs will always be isomorphic, and MOLS associated to unitarily inequivalent MUBs will be non-isomorphic

Maximally Entangled States of Four Nonbinary Particles

Systems of four nonbinary particles, each having three or more internal states, exhibit maximally entangled states that are inaccessible to four qubits. This breaks the pattern of two- and three-particle systems, in which the existing graph states are equally accessible to binary and nonbinary systems alike. We compare the entanglement properties of these special states (called P-states) with those of the more familiar GHZ and cluster states accessible to qubits. The comparison includes familiar entanglement measures, the "steering" of states by projective measurements, and the probability that two such measurements, chosen at random, leave the remaining particles in a Bell state. These comparisons demonstrate not only that P-state entanglement is stronger than the other types, but that it is maximal in a well-defined sense. We prove that GHZ, cluster, and P-states represent all possible entanglement classes of four-particle graph states with a prime number (>2) of states per particle.Comment: 26 pages, 3 figures, Appendix B proof expanded slightl

Maximally Entangled States of Four Nnonbinary Particles

Systems of four nonbinary particles, with each particle having d≥3 internal states, exhibit maximally entangled states that are inaccessible to four qubits. This breaks the pattern of two- and three-particle systems, in which the existing graph states are equally accessible to binary and nonbinary systems alike. We compare the entanglement properties of these special states (called P states) with those of the more familiar Greenberger-Horne-Zeilinger (GHZ) and cluster states accessible to qubits. The comparison includes familiar entanglement measures, the “steering” of states by projective measurements, and the probability that two such measurements, chosen at random, leave the remaining particles in a Bell state. These comparisons demonstrate not only that P-state entanglement is stronger than the other types but also that it is maximal in a well-defined sense. We prove that GHZ, cluster, and P states represent all possible entanglement classes of four-particle graph states with prime d≥3

Carbonate assimilation in open magmatic systems: the role of melt-bearing skarns and cumulate-forming processes

The geochemical characteristics of volcanic products in a variety of tectonic settings demonstrate that incorporation of crustal material into magmas is a relatively common process. Contamination of magmas by crustal components, in turn, can have a significant effect on magma composition and rheology. Despite this, the mechanism by which contamination occurs is still not well established and its efficacy is denied by some. In this study we focus on magma-carbonate interaction and on the rock shells (cumulates and skarns) formed at the contact between a magma chamber and its wall-rocks. We deduce that previous, unsuccessful attempts at carbonate assimilation-fractional crystallization (AFC) modelling can be related to the paucity of information about the cumulate zone in contact with skarns. We use one of the best examples of a magmatic plumbing system emplaced within a thick carbonate substratum (the Colli Albani Volcanic District in Central Italy) to demonstrate that a “skarn environment” can act as a source of CaO-rich silicate melts, and that the assimilation of these melts into the primitive magma is the main process responsible for magma contamination, rather than the ingestion of solid carbonate wall-rocks. In particular, by means of microtextural observations, mineral chemistry, whole-rock geochemical data and MELTS simulations we highlight the effect of high Ca-Tschermaks (CaAl2SiO6) activity in the melt on the stability of Cr-spinel, olivine, and clinopyroxene in cumulate rocks, define a reaction-cumulate zone where clinopyroxene crystallization is favoured, and model the magmatic differentiation processes active in this zone

Impulsive supply of volatile-rich magmas in the shallow plumbing system of Mt. Etna volcano

Magma dynamics at Mt. Etna volcano are frequently recognized as the result of complex crystallization regimes that, at shallow crustal levels, unexpectedly change from H2O -undersaturated to H2O-saturated conditions, due to the impulsive and irregular arrival of volatile-rich magmas from mantle depths. On this basis, we have performed hydrous crystallization experiments for a quantitative understanding of the role of H2O in the differentiation of deep-seated trachybasaltic magmas at the key pressure of the Moho transition zone. For H2O = 2.1–3.2 wt %, the original trachybasaltic composition shifts towards phonotephritic magmas never erupted during the entire volcanic activity of Mt. Etna. Conversely, for H2O = 3.8–8.2 wt %, the obtained trachybasalts and basaltic trachyandesites reproduce most of the pre-historic and historic eruptions. The comparison with previous low pressure experimental data and natural compositions from Mt. Etna provides explanation for (1) the abundant release of H2O throughout the plumbing system of the volcano during impulsive ascent of deep-seated magmas; (2) the upward acceleration of magmas feeding gas-dominated, sustained explosive eruptions; (3) the physicochemical changes of gas-fluxed magmas ponding at shallow crustal levels; and (4) the huge gas emissions measured at the summit craters and flank vents which result in a persistent volcanic gas plume

Ganciclovir penetrates into the cerebrospinal fluid of an infant with congenital cytomegalovirus infection

Currently, there is no evidence whether ganciclovir, or its oral prodrug valganciclovir, penetrates into the cerebrospinal fluid of human infants treated for congenital cytomegalovirus infection. Here we report a case study providing evidence that ganciclovir, administered as valganciclovir, reaches the infant's cerebrospinal fluid when used at the currently recommended dose for congenital cytomegalovirus infection

Contribution of Raman Spectroscopy to Diagnosis and Grading of Chondrogenic Tumors

In the last decade, Raman Spectroscopy has demonstrated to be a label-free and non-destructive optical spectroscopy able to improve diagnostic accuracy in cancer diagnosis. This is because Raman spectroscopic measurements can reveal a deep molecular understanding of the biochemical changes in cancer tissues in comparison with non-cancer tissues. In this pilot study, we apply Raman spectroscopy imaging to the diagnosis and grading of chondrogenic tumors, including enchondroma and chondrosarcomas of increasing histologic grades. The investigation included the analysis of areas of 50×50 μm2 to approximately 200×200 μm2, respectively. Multivariate statistical analysis, based on unsupervised (Principal Analysis Components) and supervised (Linear Discriminant Analysis) methods, differentiated between the various tumor samples, between cells and extracellular matrix, and between collagen and non-collagenous components. The results dealt out basic biochemical information on tumor progression giving the possibility to grade with certainty the malignant cartilaginous tumors under investigation. The basic processes revealed by Raman Spectroscopy are the progressive degrading of collagen type-II components, the formation of calcifications and the cell proliferation in tissues ranging from enchondroma to chondrosarcomas. This study highlights that Raman spectroscopy is particularly effective when cartilaginous tumors need to be subjected to histopathological analysis

Sensorless finite-control set model predictive control for IPMSM drives

This paper investigates the feasibility of a sensorless field oriented control (FOC) combined with a finite control set model predictive current control (FCS-MPC) for an interior permanent magnet synchronous motor (IPMSM). The use of a FCS-MPC makes the implementation of most of the existing sensorless techniques difficult due to the lack of a modulator. The proposed sensorless algorithm exploits the saliency of the motor and the intrinsic higher current ripple of the FCS-MPC to extract position and speed information using a model-based approach. This method does not require the injection of additional voltage vectors or the periodic interruption of the control algorithm and consequently it has no impact on the performance of the current control. The proposed algorithm has been tested in simulation and validated on an experimental set-up, showing promising results