The Applegate mechanism in Post-Common-Envelope Binaries: Investigating the role of rotation

Eclipsing time variations (ETVs) are observed in many close binary systems. In particular, for several post-common-envelope binaries (PCEBs) that consist of a white dwarf and a main sequence star, the O-C diagram suggests that real or apparent orbital period variations are driven by Jupiter-mass planets or as a result of magnetic activity, the so-called Applegate mechanism. The latter explains orbital period variations as a result of changes in the stellar quadrupole moment due to magnetic activity. We explore the feasibility of driving ETVs via the Applegate mechanism for a sample of PCEB systems, including a range of different rotations. Using the MESA code we evolve 12 stars with different masses and rotation rates. We apply a simple dynamo model to their radial profiles to investigate on which scale the predicted activity cycle matches the observed modulation period, and quantify the uncertainty, and further calculate the required energies to drive que Applegate mechanism. We show that the Applegate mechanism is energetically feasible in 5 PCEB systems, and note that these are the systems with the highest rotation rate compared to the critical rotation rate of the main-sequence star. The results suggest that the ratio of physical to critical rotation in the main sequence star is an important indicator for the feasibility of Applegate's mechanism, but exploring larger samples will be necessary to probe this hypothesis.Comment: 9 pages, 5 figures. Accepted for publication in A&

Endocardial-mesenchymal transition underlies fusion of the conotruncal ridges during embryonic cardiac outflow tract septation

The embryonic cardiac outflow tract (conotruncus) is a single tubular chamber that connects the right ventricle with the aortic arch arteries. It contains two opposite, long and helical mesenchymal cushions covered by endocardial cells (conotruncal ridges). Conotruncal division (septation) gives rise to the adult right and left outflows together with the aortic and pulmonary valves. It takes place by fusion of the two opposite ridges and formation of the conotruncal septum. Although the participation of neural crest cells in septation is well established, the mechanism of fusion of the conotruncal ridges remains unknown. Defects in fusion have been shown to produce bicuspid aortic valve, the most prevalent human congenital cardiac malformation, in a hamster model. Three fusion mechanisms have been proposed to operate during embryonic development: epithelial adhesion, epithelial apoptosis and epithelial-mesenchymal transition (EMT). The first mechanism entails the expression of adhesion molecules and the maintenance of the identity of cells in contact, whereas in the other two, epithelial cells covering the fusing structures disappear by apoptosis or by transforming into mesenchymal cells. The objective of this study is to elucidate the mechanism involved in the fusion of the conotruncal ridges. Immunofluorecence techniques were used in ED 11-12 hamster embryos. The results indicate that the mechanism of EMT, but not epithelial adhesion or apoptosis, is involved in the process of fusion of the conotruncal ridges. The EMT mechanism associated with conotruncal septation seems to be uncoupled from the process of formation of the endocardial cushions, which takes place at early stages. With these results, we can raise the hypothesis that defects in the EMT process may lead to different morphological types of bicuspid aortic valve.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This study was supported by P10-CTS-6068 (Junta de Andalucía), CGL2014-52356-P and CGL2017-85090-P (Ministerio de Economía y Competitividad), contract UMAJI75 (Junta de Andalucía, European Social Fund), and Universidad de Málaga

Trabajos de Prehistoria: su trayectoria como revista de impacto internacional

[ES] En 2008 Trabajos de Prehistoria entró en las bases de datos internacionales del SSCI, A&HCI y Scopus siendo la primera revista española del área de Arqueología con factor de impacto JCR. En el trabajo se muestra cómo este proceso de internacionalización es consecuencia de diferentes iniciativas de política científica del estado a nivel nacional y del propio CSIC. Se analiza la trayectoria de la revista desde su creación y se valora el impacto de esta internacionalización en su gestión reciente. Cabe destacar el papel[EN] Trabajos de Prehistoria was included in 2008 in the SSCI, A&HCI and Scopus international scientific databases. It was the first Spanish archaeological journal with a JCR impact factor. This paper shows how several initiatives in scientific policy by the National Spanish Government and the CSIC lead to international recognition. This study also shows the trajectory of the journal since its creation and evaluates the effects of the internationalisation on the current management. The role played by the reviewers has been fundamental in attaining and maintaining the journal’s high scientific quality.Peer reviewe

Disidencias y discordancias en la obra del escritor argentino Andrés Rivera

Antes de ser periodista y luego escritor, Andrés Rivera fue obrero textil y miembro del partido comunista argentino. Sus primeros relatos (publicados entre 1957 y 1965) están ambientados en las fábricas textiles y sus protagonistas son militantes sindicalistas. Después del proceso militar —durante el cual Rivera no pudo publicar— su obra fue marcada por cambios no solamente estéticos sino también temáticos, al tratar de la historia de su familia o de la Historia argentina. El denominador común de dichas obras es la disidencia que caracteriza a sus protagonistas, ficticios a diferentes grados ya que unos son los dobles del autor mismo y de su padre (como Arturo y Mauricio Reedson) y otros son figuras de la Historia argentina como Juan José Castelli, Juan Manuel de Rosas, o el General Paz. Proponemos estudiar primero a estos disidentes, narradores autodiegéticos de su propia historia marcada por la derrota. En una segunda parte analizaremos cómo estas voces disidentes y discordantes se manifiestan en la escritura de Rivera. En efecto, la duda, propia de los vencidos para Rivera, resalta a través de la memoria a veces borrosa de protagonistas viejos, enfermos o delirantes, quienes se preguntan cómo no pudieron hacer escuchar su voz. La historia personal de cada uno se superpone a la Historia, y la subjetividad del relato expone en una fragmentación tanto discursiva como cronotópica diferentes versiones de la Historia, problematizando su escritura misma

Bulge RR Lyrae stars in the VVV tile b201\textit{b201}

The VISTA Variables in the V\'ia L\'actea (VVV) Survey is one of the six ESO public surveys currently ongoing at the VISTA telescope on Cerro Paranal, Chile. VVV uses near-IR ($ZYJHK_{\rm s}$) filters that at present provide photometry to a depth of $K_{\rm s} \sim 17.0$ mag in up to 36 epochs spanning over four years, and aim at discovering more than 10$^6$ variable sources as well as trace the structure of the Galactic bulge and part of the southern disk. A variability search was performed to find RR Lyrae variable stars. The low stellar density of the VVV tile $\textit{b201}$, which is centered at ($\ell, b$) $\sim$ ($-9^\circ, -9^\circ$), makes it suitable to search for variable stars. Previous studies have identified some RR Lyrae stars using optical bands that served to test our search procedure. The main goal is to measure the reddening, interstellar extinction, and distances of the RR Lyrae stars and to study their distribution on the Milky Way bulge. A total of 1.5 sq deg were analyzed, and we found 39 RR Lyrae stars, 27 of which belong to the ab-type and 12 to the c-type. Our analysis recovers all the previously identified RR Lyrae variables in the field and discovers 29 new RR Lyrae stars. The reddening and extinction toward all the RRab stars in this tile were derived, and distance estimations were obtained through the period--luminosity relation. Despite the limited amount of RR Lyrae stars studied, our results are consistent with a spheroidal or central distribution around $\sim 8.1$ and $\sim 8.5$ kpc. for either the Cardelli or Nishiyama extinction law.Comment: 10 pages, 8 figures, accepted for publication in Astronomy and Astrophysic

Inducing nonclassical lasing via periodic drivings in circuit quantum electrodynamics

We show how a pair of superconducting qubits coupled to a microwave cavity mode can be used to engineer a single-atom laser that emits light into a nonclassical state. Our scheme relies on the dressing of the qubit-field coupling by periodic modulations of the qubit energy. In the dressed basis, the radiative decay of the first qubit becomes an effective incoherent pumping mechanism that injects energy into the system, hence turning dissipation to our advantage. A second, auxiliary qubit is used to shape the decay within the cavity, in such a way that lasing occurs in a squeezed basis of the cavity mode. We characterize the system both by mean-field theory and exact calculations. Our work may find applications in the generation of squeezing and entanglement in circuit QED, as well as in the study of dissipative few- and many-body phase transitions