On the Response Function Technique for Calculating the Random-Phase Approximation Correlation Energy

We develop a scheme to exactly evaluate the correlation energy in the random-phase approximation, based on linear response theory. It is demonstrated that our formula is completely equivalent to a contour integral representation recently proposed by Donau et al. being numerically more efficient for realistic calculations. Numerical examples are presented for pairing correlations in rapidly rotating nuclei.Comment: 4 pages, 4 figure

A polarity reversal in the large-scale magnetic field of the rapidly rotating Sun HD 190771

Aims. We investigate the long-term evolution of the large-scale photospheric magnetic field geometry of the solar-type star HD 190771. With fundamental parameters very close to those of the Sun except for a shorter rotation period of 8.8 d, HD 190771 provides us with a first insight into the specific impact of the rotation rate in the dynamo generation of magnetic fields in 1 $M_\odot$ stars. Methods. We use circularly polarized, high-resolution spectra obtained with the NARVAL spectropolarimeter (Observatoire du Pic du Midi, France) and compute cross-correlation line profiles with high signal-to-noise ratio to detect polarized Zeeman signatures. From three phase-resolved data sets collected during the summers of 2007, 2008, and 2009, we model the large-scale photospheric magnetic field of the star by means of Zeeman-Doppler imaging and follow its temporal evolution. Results. The comparison of the magnetic maps shows that a polarity reversal of the axisymmetric component of the large-scale magnetic field occurred between 2007 and 2008, this evolution being observed in both the poloidal and toroidal magnetic components. Between 2008 and 2009, another type of global evolution occured, characterized by a sharp decrease of the fraction of magnetic energy stored in the toroidal component. These changes were not accompanied by significant evolution in the total photospheric magnetic energy. Using our spectra to perform radial velocity measurements, we also detect a very low-mass stellar companion to HD 190771.Comment: Accepted by Astronomy and Astrophysics (Letter to the Editor

Abundances and kinematics for ten anticentre open clusters

Open clusters are distributed all across the disk and are convenient tracers of its properties. In particular, outer disk clusters bear a key role for the investigation of the chemical evolution of the Galactic disk. The goal of this study is to derive homogeneous elemental abundances for a sample of ten outer disk OCs, and investigate possible links with disk structures such as the Galactic Anticenter Stellar Structure. We analyse high-resolution spectra of red giants, obtained from the HIRES@Keck and UVES@VLT archives. We derive elemental abundances and stellar atmosphere parameters by means of the classical equivalent width method. We also performed orbit integrations using proper motions. The Fe abundances we derive trace a shallow negative radial metallicity gradient of slope -0.027+/-0.007 dex.kpc-1 in the outer 12 kpc of the disk. The [alpha/Fe] gradient appears flat, with a slope of 0.006+/-0.007 dex.kpc-1 . The two outermost clusters (Be 29 and Sau 1) appear to follow elliptical orbits. Be 20 also exhibits a peculiar orbit with a large excursion above the plane. The irregular orbits of the three most metal-poor clusters (of which two are located at the edge of the Galactic disk), if confirmed by more robust astrometric measurements such as those of the Gaia mission, are compatible with an inside-out formation scenario for the Milky Way, in which extragalactic material is accreted onto the outer disk. We cannot determine if Be 20, Be 29,and Sau 1 are of extragalactic origin, as they may be old genuine Galactic clusters whose orbits were perturbed by accretion events or minor mergers in the past 5 Gyr, or they may be representants of the thick disk population. The nature of these objects is intriguing and deserves further investigations in the near future.Comment: 17 pages, 9 figures; accepted for publication in A&

Photometric and spectroscopic study of the intermediate-age open cluster NGC 2355

In this paper we analyse the evolutionary status and properties of the old open cluster NGC 2355, located in the Galactic anticentre direction, as a part of the long term programme BOCCE. NGC 2355 was observed with LBC@LBT using the Bessel $B$, $V$, and $I_c$ filters. The cluster parameters have been obtained using the synthetic colour-magnitude diagram (CMD) method, as done in other papers of this series. Additional spectroscopic observations with FIES@NOT of three giant stars were used to determine the chemical properties of the cluster. Our analysis shows that NGC 2355 has metallicity slightly less than solar, with [Fe/H]$=-0.06$ dex, age between 0.8 and 1 Gyr, reddening $E(B-V)$ in the range 0.14 and 0.19 mag, and distance modulus $(m-M)_0$ of about 11 mag. We also investigated the abundances of O, Na, Al, $\alpha$, iron-peak, and neutron capture elements, showing that NGC 2355 falls within the abundance distribution of similar clusters (same age and metallicity). The Galactocentric distance of NGC~2355 places it at the border between two regimes of metallicity distribution; this makes it an important cluster for the study of the chemical properties and evolution of the disc.Comment: 20 pages, 11 figures, Accepted on MNRA

NGC 6535: the lowest mass Milky Way globular cluster with a Na-O anti-correlation? Cluster mass and age in the multiple population context

To understand globular clusters (GCs) we need to comprehend how their formation process was able to produce their abundance distribution of light elements. In particular, we seek to figure out which stars imprinted the peculiar chemical signature of GCs. One of the best ways is to study the light-element anti-correlations in a large sample of GCs that are analysed homogeneously. As part of our spectroscopic survey of GCs with FLAMES, we present here the results of our study of about 30 red giant member stars in the low-mass, low-metallicity Milky Way cluster NGC 6535. We measured the metallicity (finding [Fe/H]=-1.95, rms=0.04 dex in our homogeneous scale) and other elements of the cluster and, in particular, we concentrate here on O and Na abundances. These elements define the normal Na-O anti-correlation of classical GCs, making NGC 6535 perhaps the lowest mass cluster with a confirmed presence of multiple populations. We updated the census of Galactic and extragalactic GCs for which a statement on the presence or absence of multiple populations can be made on the basis of high-resolution spectroscopy preferentially, or photometry and low-resolution spectroscopy otherwise; we also discuss the importance of mass and age of the clusters as factors for multiple populations.Comment: In press on A&A. Table 2 available at CD

NGC 6139: a normal massive globular cluster or a first-generation dominated cluster? Clues from the light elements

Information on globular clusters (GC) formation mechanisms can be gathered by studying the chemical signature of the multiple populations that compose these stellar systems. In particular, we are investigating the anticorrelations among O, Na, Al, and Mg to explore the influence of cluster mass and environment on GCs in the Milky Way and in extragalactic systems. We present here the results obtained on NGC 6139 which, on the basis of its horizontal branch morphology, had been proposed to be dominated by first-generation stars. In our extensive study based on high resolution spectroscopy, the first for this cluster, we found a metallicity of [Fe/H]= -1.579 +/- 0.015 +/- 0.058 (rms=0.040 dex, 45 bona fide member stars) on the UVES scale defined by our group. The stars in NGC 6139 show a chemical pattern normal for GCs, with a rather extended Na-O (and Mg-Al) anticorrelation. NGC 6139 behaves like expected from its mass and contains a large fraction (about two thirds) of second-generation stars.Comment: Accepted for publication on A&

Magnetic cycles of the planet-hosting star tauBootis

We have obtained new spectropolarimetric observations of the planet-hosting star tauBootis, using the ESPaDOnS and NARVAL spectropolarimeters at the Canada-France-Hawaii Telescope and Telescope Bernard-Lyot. With this data set, we are able to confirm the presence of a magnetic field at the surface of tauBoo and map its large-scale structure over the whole star. The overall polarity of the magnetic field has reversed with respect to our previous observation (obtained a year before), strongly suggesting that tauBoo is undergoing magnetic cycles similar to those of the Sun. This is the first time that a global magnetic polarity switch is observed in a star other than the Sun; we speculate that the magnetic cycle period of tauBoo is much shorter than that of the Sun. Our new data also allow us to confirm the presence of differential rotation from the latitudinal shearing that the magnetic structure is undergoing. The differential rotation surface shear that tauBoo experiences is found to be 6 to 10 times larger than that of the Sun. We propose that the short magnetic cycle period is due to the strong level of differential rotation. With a rotation period of 3.0 and 3.9 d at the equator and pole respectively, tauBoo appears as the first planet-hosting star whose rotation (at intermediate latitudes) is synchronised with the orbital motion of its giant planet (period 3.3 d). Assuming that this synchronisation is not coincidental, it suggests that the tidal effects induced by the giant planet can be strong enough to force the thin convective enveloppe (though not the whole star) into corotation and thus to play a role in the activity cycle of tauBoo.Comment: MNRAS, in pres

Revolutionizing PIP joint fracture treatment: A case of surgical precision and rapid recovery

Introduction: Proximal interphalangeal joint (PIPj) fractures are a common yet challenging injury, particularly in athletes. This case study explores innovative surgical techniques combined with targeted rehabilitation to optimize recovery and functionality. Case presentation: A 20-year-old male soccer goalkeeper sustained a severe Proximal Interphalangeal Joint fracture-dislocation of the third finger during a game. He was treated using the wide awake local anesthesia no tourniquet (WALANT) technique and a Medartis TriLock plate, originally designed for the proximal phalanx but adapted for use on the middle phalanx. Clinical discussion: Immediate postoperative mobilization was facilitated by the WALANT technique, enhancing pain management and functional recovery. The adaptation of the TriLock plate, typically not used in this context, proved crucial for stabilizing the complex fracture. Follow-up included regular physiotherapy, focusing on mobility exercises and strength training, which were instrumental in the patient's quick return to sport. Conclusions: This case underscores the effectiveness of combining innovative surgical adaptations with early rehabilitation in treating complex hand injuries. Such approaches can lead to successful outcomes, significantly improving recovery times and functional results in athletic populations. This strategy may set a precedent for future treatment protocols in sports-related hand injuries

Non-surgical treatment of oblique diaphyseal fractures of the fourth and fifth metacarpals in a professional athlete: A case report

Introduction: Metacarpal fractures are common sports-related injuries, often requiring tailored treatment strategies, especially in athletes. The management of oblique diaphyseal fractures poses unique challenges due to their inherent instability. This case report discusses a non-surgical approach in treating such fractures in a professional athlete. Case presentation: A 26-year-old professional soccer player sustained oblique diaphyseal fractures of the fourth and fifth metacarpals during training. Given the athlete's professional demands and the fracture's nature, a conservative treatment was implemented. This included the application of a modified ulnar gutter brace, allowing for immobilization of the metacarpophalangeal joints (MP) while permitting active mobilization of the interphalangeal joints(IP). Clinical discussion: The non-surgical treatment focused on achieving skeletal stability and maintaining hand function. Despite the complexity of oblique fractures, the conservative approach was successful, enabling the athlete to resume professional activities with minimal risk of fracture displacement. Regular radiographic follow-ups showed no further displacement, highlighting the effective management of such fractures through personalized conservative treatment plans. Conclusions: This case underscores the viability of conservative treatment for specific metacarpal fractures in athletes. Tailoring the treatment to accommodate the athlete's professional needs and understanding the biomechanical characteristics of the fracture are crucial for successful outcomes. The case also suggests that non-surgical management can be a viable option for certain complex metacarpal fractures, especially in high-demand patients

“Review of contemporary non-surgical management techniques for metacarpal fractures: Anatomy and rehabilitation strategies”

This comprehensive study explores the various aspects of metacarpal fractures, a prevalent condition in hand injuries. We delve into the anatomy of the metacarpals, elucidating how their structural characteristics influence fracture mechanics and treatment options. Special attention is given to the diverse types of fractures, particularly the differing tolerances for angular, shortening, and rotational deformities. The manuscript extensively reviews conservative treatment approaches, emphasizing the efficacy of non-surgical methods like modified braces and active mobilization techniques. Additionally, we provide a nuanced understanding of specific fracture types, such as neck fractures, highlighting their unique healing dynamics. This research offers valuable insights for orthopedic and plastic surgery practitioners, advancing the understanding and management of metacarpal fractures