The central parsecs of M87: jet emission and an elusive accretion disc

We present the first simultaneous spectral energy distribution (SED) of M87 core at a scale of 0.4 arcsec ($\sim 32\, \rm{pc}$) across the electromagnetic spectrum. Two separate, quiescent, and active states are sampled that are characterized by a similar featureless SED of power-law form, and that are thus remarkably different from that of a canonical active galactic nuclei (AGN) or a radiatively inefficient accretion source. We show that the emission from a jet gives an excellent representation of the core of M87 core covering ten orders of magnitude in frequency for both the active and the quiescent phases. The inferred total jet power is, however, one to two orders of magnitude lower than the jet mechanical power reported in the literature. The maximum luminosity of a thin accretion disc allowed by the data yields an accretion rate of $< 6 \times 10^{-5}\, \rm{M_\odot \, yr^{-1}}$, assuming 10% efficiency. This power suffices to explain M87 radiative luminosity at the jet-frame, it is however two to three order of magnitude below that required to account for the jet's kinetic power. The simplest explanation is variability, which requires the core power of M87 to have been two to three orders of magnitude higher in the last 200 yr. Alternatively, an extra source of power may derive from black hole spin. Based on the strict upper limit on the accretion rate, such spin power extraction requires an efficiency an order of magnitude higher than predicted from magnetohydrodynamic simulations, currently in the few hundred per cent range.Comment: 18 pages, 6 figures. Accepted for publication in MNRA

Chemotherapy-free treatments: are we ready for prime time?

Epithelial ovarian cancer (EOC) is most frequently diagnosed at an advanced stage and, despite high response rates to initial taxane-platinum-based chemotherapy, more than 70% of patients will develop recurrent disease and will receive several chemotherapy treatments. At present, the 5-year overall survival (OS) for women diagnosed with stage III–IV disease is 46% and patients with genetic impairments of DNA repair pathways [BRCA mutations and in general homologous recombination deficiency (HRD)] live longer and possibly will receive even more lines of chemotherapy

Alteraciones de la superficie del cuerpo vertebral en una población medieval de Logroño (s. XI y XII)

X Congreso Nacional de Paleopatología. Univesidad Autónoma de Madrid, septiembre de 200

Interaction Effects on the Magneto-optical Response of Magnetoplasmonic Dimers

The effect that dipole-dipole interactions have on the magneto-optical (MO) properties of magnetoplasmonic dimers is theoretically studied. The specific plasmonic versus magnetoplasmonic nature of the dimer's metallic components and their specific location within the dimer plays a crucial role on the determination of these properties. We find that it is possible to generate an induced MO activity in a purely plasmonic component, even larger than that of the MO one, therefore dominating the overall MO spectral dependence of the system. Adequate stacking of these components may allow obtaining, for specific spectral regions, larger MO activities in systems with reduced amount of MO metal and therefore with lower optical losses. Theoretical results are contrasted and confirmed with experiments for selected structures

A dark energy multiverse

We present cosmic solutions corresponding to universes filled with dark and phantom energy, all having a negative cosmological constant. All such solutions contain infinite singularities, successively and equally distributed along time, which can be either big bang/crunchs or big rips singularities. Classicaly these solutions can be regarded as associated with multiverse scenarios, being those corresponding to phantom energy that may describe the current accelerating universe

First detection of the 448 GHz H2O transition in space

We present the first detection of the ortho-H2O 4_23-3_30 transition at 448 GHz in space. We observed this transition in the local (z = 0.010) luminous infrared (IR) galaxy ESO 320-G030 (IRAS F11506-3851) using the Atacama Large Millimeter/submillimeter Array (ALMA). The water 4_23-3_30 emission, which originates in the highly obscured nucleus of this galaxy, is spatially resolved over a region of ~65 pc in diameter and shows a regular rotation pattern compatible with the global molecular and ionized gas kinematics. The line profile is symmetric and well fitted by a Gaussian with an integrated flux of 37.0 +- 0.7 Jy km s-1 . Models predict this water transition as a potential collisionally excited maser transition. On the contrary, in this galaxy, we find that the 4_23-3_30 emission is primarily excited by the intense far-IR radiation field present in its nucleus. According to our modeling, this transition is a probe of deeply buried galaxy nuclei thanks to the high dust optical depths (tau_100{\mu}m > 1, N_H > 1e24 cm-2) required to efficiently excite it.Comment: Accepted for publication in A&A Letters; 4 pages, 5 figure

On the generalised Chaplygin gas: worse than a big rip or quieter than a sudden singularity?

Although it has been believed that the models with generalised Chaplygin gas do not contain singularities, in a previous work we have studied how a big freeze could take place in some kinds of phantom generalised Chaplygin gas. In the present work, we study some types of generalised Chaplygin gas in order to show how different sorts of singularities could appears in such models, in the future or in the past. We point out that: (i) singularities may not be originated from the phantom nature of the fluid, and (ii) if initially the tension of the brane in a brane-world Chaplygin model is large enough then an infrared cut off appears in the past.Comment: 19 pages, 6 figures. Discussion expanded and references added. Version to appear in the International Journal of Modern Physics

A graceful multiversal link of particle physics to cosmology

In this paper we work out a multiverse scenario whose physical characteristics enable us to advance the following the conjecture that whereas the physics of particles and fields is confined to live in the realm of the whole multiverse formed by finite-time single universes, that for our observable universe must be confined just in one of the infinite number of universes of the multiverse when such a universe is consistently referred to an infinite cosmic time. If this conjecture is adopted then some current fundamental problems that appear when one tries to make compatible particle physics and cosmology- such as that for the cosmological constant, the arrow of time and the existence of a finite proper size of the event horizon- can be solved.Comment: 10 pages, LaTe

Nanofabrication and Electrochemical Characterization of Self-Assembled Monolayers Sandwiched between Metal Nanoparticles and Electrode Surfaces

Nanoscience and nanotechnology have reached the syllabi of many upper-division undergraduate and master-level courses all over the world. There is therefore a growing need for practical exercises that illustrate the fabrication, characterization, properties, and applications of nanomaterials. Here we describe an advanced-level laboratory experiment in which students had the opportunity to fabricate surfaces modified by ordered monolayers and nanostructured materials. The surface modification was quantified by means of a quartz crystal microbalance, while the electrochemical properties of the nanoarchitectures were assessed using cyclic voltammetry experiments. Electron transfer across self-assembled monolayers mediated by gold nanoparticles was presented as a topic for discussion, and consideration of potential practical applications of the observed phenomena (catalytic and electrocatalytic processes, as well as development of optical, (opto)electronic, and photovoltaic devices with enhanced properties) was proposed as a further reading exercise