Constraining the Milky Way potential using the dynamical kinematic substructures

We present a method to constrain the potential of the non-axisymmetric components of the Galaxy using the kinematics of stars in the solar neighborhood. The basic premise is that dynamical substructures in phase-space (i.e. due to the bar and/or spiral arms) are associated with families of periodic or irregular orbits, which may be easily identified in orbital frequency space. We use the "observed" positions and velocities of stars as initial conditions for orbital integrations in a variety of gravitational potentials. We then compute their characteristic frequencies, and study the structure present in the frequency maps. We find that the distribution of dynamical substructures in velocity- and frequency-space is best preserved when the integrations are performed in the "true" gravitational potential.Comment: 2 pages, 4 figures, to appear in the proceedings of "Assembling the Puzzle of the Milky Way", Le Grand Bornand (Apr. 17-22, 2011

The imprints of the Galactic Bar on the Thick Disk with RAVE

We study the kinematics of a local sample of stars, located within a cylinder of 500 pc radius centered on the Sun, in the RAVE data set. We find clear asymmetries in the v R v∞ velocity distributions of thin and thick disk stars: there are more stars moving radially outward for low azimuthal velocities and more radially inward for high azimuthal velocities. Such asymmetries have been previously reported for the thin disk as being due to the Galactic bar, but this is the first time that the same type of structures are seen in the thick disk. Our findings imply that the velocities of thick-disk stars should no longer be described by Schwarzschilds, multivariate Gaussian or purely axisymmetric distributions. Furthermore, the nature of previously reported substructures in the thick disk needs to be revisited as these could be associated with dynamical resonances rather than to accretion events. It is clear that dynamical models of the Galaxy must fit the 3D velocity distributions of the disks, rather than the projected 1D, if we are to understand the Galaxy fully

Tracing the Hercules stream with Gaia and LAMOST: new evidence for a fast bar in the Milky Way

The length and pattern speed of the Milky Way bar are still controversial. Photometric and spectroscopic surveys of the inner Galaxy, as well as gas kinematics, favour a long and slowly rotating bar, with corotation around a Galactocentric radius of 6 kpc. On the other hand, the existence of the Hercules stream in local velocity space favours a short and fast bar with corotation around 4 kpc. This follows from the fact that the Hercules stream looks like a typical signature of the outer Lindblad resonance of the bar. As we showed recently, reconciling this local stream with a slow bar would need to find a yet unknown alternative explanation, based for instance on the effect of spiral arms. Here, by combining the TGAS catalogue of the Gaia DR1 with LAMOST radial velocities, we show that the position of Hercules in velocity space as a function of radius in the outer Galaxy indeed varies exactly as predicted by fast bar models with a pattern speed no less than 1.8 times the circular frequency at the Sun's position

Full-Configuration-Interaction Study of the Metal-Insulator Transition in Model Systems: Li_N Linear Chains (N=2,4,6,8)

International audienceThe precursor of the metal-insulator transition is studied at ab initio level in linear chains of equally spaced lithium atoms. In particular, full configuration interaction calculations (up to 1×109 determinants) are performed, in order to take into account the different nature of the wave function at different internuclear distances. Several indicators of the Metal-Insulator transition (minimum of the energy gap, maximum of the localization tensor or of the polarizability) are considered and discussed. It is shown that the different indicators give concordant results, showing a rapid change in the nature of the wave function at an internuclear distance of about 7bohrs

Anti-Phospholipase A2 Receptor Antibodies in Membranous Nephropathy : from Bench to the Patient

Membranous Nephropathy (MN) is the leading cause of nephrotic syndrome in adults. Primary or idiopathic Membranous Nephropathy (iMN) has been considered as an organ-specific autoimmune disease with an unknown aetiology. By contrast, secondary membranous nephropathy has been described as the expression of a systemic autoimmune response to malignancy or bacterial/viral infections. In the majority of iMN cases, glomerular lesions are determined by autoantibodies against a podocyte membrane protein, the M-type of phospholipase A2 receptor 1 (PLA2R1). Several studies have suggested that the detection of anti-PLA2R1 in patients sera with nephrotic syndrome may be pathognomonic of iMN, thus obviating the need for a diagnostic renal biopsy and an extensive workup for underlying causes. Many authors inferred that the measurement of anti-PLA2R1 may change the diagnostic algorithm in patients with nephrotic syndrome and guide treatment decisions in patients with iMN. Measurement of anti-PLA2R1 antibodies is now possible through an easy to use, commercially available assay. The aim of this review is to describe the clinical relevance of anti-PLA2R1 assessment in patients with MN, and to extensively discuss the biotechnological methods available to measure them

Induction of Labor According to Medical Indications: A Critical Evaluation through a Prospective Study

Background: The induction of labor (IOL) is a common obstetric intervention, steadily increasing (one out four pregnancies) in the last years. This procedure should be considered only when there is a medical indication, and when the benefits outweigh the maternal and/or fetal risks of waiting for spontaneous onset of labor. Therefore, this study aims to compare the efficacy of the IOL in terms of induction to delivery time, mode of delivery, and neonatal well-being among different evidence-based and non-evidence-based indications. Methods: This prospective study was conducted at the University Hospital of Modena, between January and December 2020. We included singleton pregnant women undergoing IOL, at the term. Intrauterine deaths, small for gestational age fetuses <5th centile as well women with hypertensive disorders were excluded. Women have been subdivided into 3 groups based on the indication to IOL: premature rupture of membranes (PROM), post-date pregnancy (>41 weeks + 3 days), and non-evidence-based indications (NEBI). The primary outcome is the time occurring between IOL and delivery (TIME), analyzing separately by parity. Moreover, mode of delivery and neonatal wellbeing were evaluated. Results: A total of 585 women underwent IOL in the study period. Overall, the median TIME between IOL and delivery was 19 hours, and the mean cesarean section CS rate was 15.5% (91/585). Pregnancies induced for postdate and non-evidencebased indications registered respectively a significantly higher mean time (p < 0.001), compared with women induced for PROM. This occurred both in nulliparous and multiparous women. Moreover, at multivariate analysis, the IOL TIME ≥24 hours was significantly influenced by Bishop score (p = 0.000) and NEBI (p = 0.02) in nulliparous and by gestational age (p = 0.000) and NEBI (p = 0.02) in multiparous. Moreover, CS rate was significantly influenced by Bishop score (p = 0.003) in nulliparous and by gestational age (p = 0.01) in multiparous. Finally, neonatal intensive care unit (NICU) admission resulted significantly influenced only by gestational age (p = 0.002) in multiparous. Conclusions: Our study confirms that IOL in non-evidence-based indications, leads to an increase in induction to delivery time comparing with women induced for PROM, both in nulliparous and multiparous women, thus it should be justified and carefully evaluated. Further randomized controlled trials (RCT) conducted in European/Italian settings are needed to determine the perinatal outcomes of IOL in non-evidence-based indications

Ruthenium-thymine acetate binding modes: Experimental and theoretical studies

Ruthenium complexes have proved to exhibit antineoplastic activity, related to the interaction of the metal ion with DNA. In this context, synthetic and theoretical studies on ruthenium binding modes of thymine acetate (THAc) have been focused to shed light on the structure-activity relationship. This report deals with the reaction between dihydride ruthenium mer-[Ru(H)2(CO)(PPh3)3], 1 and the thymine acetic acid (THAcOH) selected as model for nucleobase derivatives. The reaction in refluxing toluene between 1 and THAcOH excess, by H2 release affords the double coordinating species k1-(O)THAc-, k2-(O,O)THAc-[Ru(CO)(PPh3)2], 2. The X-ray crystal structure confirms a simultaneous monohapto, dihapto- THAc coordination in a reciprocal facial disposition. Stepwise additions of THAcOH allowed to intercept the monohapto mer-k1(O)THAc-Ru(CO)H(PPh3)3] 3 and dihapto trans(P,P)-k2(O,O)THAc-[Ru(CO)H(PPh3)2] 4 species. Nuclear magnetic resonance (NMR) studies, associated with DFT (Density Function Theory)-calculations energies and analogous reactions with acetic acid, supported the proposed reaction path. As evidenced by the crystal supramolecular hydrogen-binding packing and 1H NMR spectra, metal coordination seems to play a pivotal role in stabilizing the minor [(N=C(OH)] lactim tautomers, which may promote mismatching to DNA nucleobase pairs as a clue for its anticancer activity

Stars with fast Galactic rotation observed in Gaia TGAS: a signature driven by the Perseus arm?

We report on the detection of a small overdensity of stars in velocity space with systematically higher Galactocentric rotation velocity than the Sun by about 20 km s$^{-1}$ in the $Gaia$ Data Release 1 Tycho-Gaia astrometric solution (TGAS) data. We find these fast Galactic rotators more clearly outside of the Solar radius, compared to inside of the Solar radius. In addition, the velocity of the fast Galactic rotators is independent of the Galactocentric distance up to $R-R_{\odot}\sim0.6$ kpc. Comparing with numerical models, we qualitatively discuss that a possible cause of this feature is the co-rotation resonance of the Perseus spiral arm, where the stars in peri-centre phase in the trailing side of the Perseus spiral arm experience an extended period of acceleration owing to the torque from the Perseus arm

Stereochemistry of the insertion of disubstituted alkynes into the metal aminocarbyne bond in diiron complexes

Terminal alkynes (HCdropCR') (R'=COOMe, CH2OH) insert into the metal-carbyne bond of the diiron complexes [Fe-2{mu-CN(Me)(R)} (mu-CO)(CO)(NCMe)(Cp)(2)][SO3CF3] (R=Xyl, 1a; CH2Ph, 1b; Me, 1c; Xyl=2,6-Me2C6H3), affording the corresponding mu-vinyliminium complexes [Fe-2{mu-sigma:eta(3)-C(R')=CHC=N(Me)(R)}(mu-CO)(CO)(Cp)(2)][SO3CF3] (R=Xyl, R'=COOMe, 2; R=CH2Ph, R'=COOMe, 3; R=Me, R'=COOMe, 4; R=Xyl, R'=CH2OH, 5; R=Me, R'=CH2OH, 6). The insertion is regiospecific and C-C bond formation selectively occurs between the carbyne carbon and the CH moiety of the alkyne. Disubstituted alkynes (R'CdropCR') also insert into the metal-carbyne bond leading to the formation of [Fe-2{mu-sigma:eta(3)- C(R')=C(R')C=N(Me)(R)}(mu-CO)(CO)(Cp)(2)][SO3CF3] (R'=Me, R=Xyl, 8; R'=Et, R=Xyl, 9; R'=COOMe, R=Xyl, 10; R'=COOMe, R=CH2Ph, 11; R'= COOMe, R=Me, 12). Complexes 2, 3, 5, 8, 9 and 11, in which the iminium nitrogen is unsymmetrically substituted, give rise to E and/or Z isomers. When iminium substituents are Me and Xyl, the NMR and structural investigations (X-ray structure analysis of 2 and 8) indicate that complexes obtained from terminal alkynes preferentially adopt the E configuration, whereas those derived from internal alkynes are exclusively Z. In complexes 8 and 9, trans and cis isomers have been observed, by NMR spectroscopy, and the structures of trans-8 and cis-8 have been determined by X-ray diffraction studies. Trans to cis isomerization occurs upon heating in THF at reflux temperature. In contrast to the case of HCdropCR', the insertion of 2-hexyne is not regiospecific: both [Fe-2{mu-sigma:eta(3)-C(CH2CH2CH3)=C(Me)C=N(Me)(R)} (mu-CO)(CO)(Cp)(2)][SO3CF3] (R=Xyl, 13; R=Me, 15) and [Fe-2{mu-sigma:eta(3)-C(Me)=C(CH2CH2CH3)C=N(Me)(R)}(mu-CO)(CO)(Cp)(2)][SO3CF3] (R=Xyl, 14, R=Me, 16) are obtained and these compounds are present in solution as a mixture of cis and trans isomers, with predominance of the former