El concepto de diversidad vegetal desde la etnia mapuche a la enseñanza formal en Chile

El estudio de la terminología botánica en la lengua mapuche revela la gran importancia que la diversidad vegetal ha tenido para sus tradiciones y usos. Un colectivo de estudiantes de enseñanza media de origen mapuche conserva entre sus conocimientos de biología vegetal un rico aporte de esta información etnobotánica; sin embargo estudiantes que inician estudios universitarios de ingeniería forestal y agronomía muestran un nivel de conocimiento muy inferior. La enseñanza formal chilena puede aprovechar este potencial cultural para incorporarlo en una educación científica intercultural que favorezca la protección y respeto de los ecosistemas del Chile Central gravemente amenazados por los intereses de las grandes multinacionales que explotan sus recursos naturales

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

Searching for a dipole modulation in the large-scale structure of the Universe

Several statistical anomalies in the CMB temperature anisotropies seem to defy the assumption of a homogeneous and isotropic universe. In particular, a dipole modulation has been detected both in WMAP and Planck data. We adapt the methodology proposed by Eriksen et al. (2007) on CMB data to galaxy surveys, tracing the large-scale structure. We analyse the NRAO VLA Sky Survey (NVSS) data at a resolution of ~2 degrees for three different flux thresholds: 2.5, 5.0 and 10.0 mJy respectively. No evidence of a dipole modulation is found. This result suggests that the origin of the dipole asymmetry found in the CMB cannot be assigned to secondary anisotropies produced at redshifts around z = 1. However, it could still have been generated at redshifts higher or lower, such as the integrated Sachs-Wolfe effect produced by the local structures. Other all-sky surveys, like the infrared WISE catalogue, could help to explore with a high sensitivity a redshift interval closer than the one probed with NVSS.Comment: 6 pages, 2 figures. Some minor changes have been done from the original manuscript. This paper is accepted by MNRA

Gapless Hamiltonians for the toric code using the PEPS formalism

We study Hamiltonians which have Kitaev's toric code as a ground state, and show how to construct a Hamiltonian which shares the ground space of the toric code, but which has gapless excitations with a continuous spectrum in the thermodynamic limit. Our construction is based on the framework of Projected Entangled Pair States (PEPS), and can be applied to a large class of two-dimensional systems to obtain gapless "uncle Hamiltonians".Comment: 8 pages, 2 figure

Charge control in laterally coupled double quantum dots

We investigate the electronic and optical properties of InAs double quantum dots grown on GaAs (001) and laterally aligned along the [110] crystal direction. The emission spectrum has been investigated as a function of a lateral electric field applied along the quantum dot pair mutual axis. The number of confined electrons can be controlled with the external bias leading to sharp energy shifts which we use to identify the emission from neutral and charged exciton complexes. Quantum tunnelling of these electrons is proposed to explain the reversed ordering of the trion emission lines as compared to that of excitons in our system.Comment: 4 pages, 4 figures submitted to PRB Rapid Com

Estimation of the reference points for the different OMs in the Cod 3M MSE

This paper presents different methods to estimate the reference points (Blim, Bmsy and Fmsy) to be used in the 3M NAFO cod MSE. Reference points should be specific for each of the possible realities, what defines the different possible realities are the different OMs and, within each OM, the different iterations. The methods presented here try to estimate the reference points by iteration for the different OMs since it is assuming that the reference points will be interpreted as a characteristic of the “real” population. The results of some of the methods proposed to estimate the management reference points (limit and target) seem to be not consistent between them. The results show that in this case the proxy used as Fmsy (F30%SpR) seems quite reasonable

Standardized CPUE Indices for Greenland Halibut in NAFO Regulatory Area of Divisions 3LMNO Based on Spanish Commercial Catch Rates

A standardized CPUE series using a log-linear model for Greenland halibut in NAFO Regulatory Area of Divisions 3LMNO, based on catch and effort data from the Spanish trawl fleet since 1992 is presented. Fixed factors considered in the model were year, month, division, depth stratum and vessel and the interactions included were division*month and division*depth stratum. All of these factors and interactions are statistically significant. The total proportion of variance explained by this model is 46%. The results indicate substantial variability of CPUE over time, with several short periods of increasing and decreasing CPUE. After having reached the lowest value of the series in 2004, standardized CPUE has increased very substantially, reaching a value in 2006 very near the maximum of the entire series

Assessment of the Cod Stock in NAFO Division 3M

An assessment of the cod stock in NAFO Division 3M was conducted using a Bayesian SCAA (statistical catch-at-age) model. The STACFIS catch estimates and the Flemish Cap survey indices were used to fit the model. Blim, defined as the SSB of 2007, was estimated at 15 408 t (median). Results indicate a general increase in SSB since 2005 to the highest value in 2017, decreasing sharply since then. SSB has been above Blim since 2008. Between 2013 and 2018 recruitment was at very low levels; the 2016 and 2018 values were among the lowest of the series; as a consequence, 3-year projections indicate that total biomass will decrease during the projected years, while the SSB could increase under some scenarios in the final projected year. Depending on the projected scenario, probability of SSB being below Blim in 2023 and 2024 is high (≥12%) or very low (≤5%). An increase in recruitment occurred in 2019 and 2020, reaching the 2008 level.Versión del editor

Nonlinear Pseudo-Supersymmetry in the Framework of N-fold Supersymmetry

We recall the importance of recognizing the different mathematical nature of various concepts relating to PT-symmetric quantum theories. After clarifying the relation between supersymmetry and pseudo-supersymmetry, we prove generically that nonlinear pseudo-supersymmetry, recently proposed by Sinha and Roy, is just a special case of N-fold supersymmetry. In particular, we show that all the models constructed by these authors have type A 2-fold supersymmetry. Furthermore, we prove that an arbitrary one-body quantum Hamiltonian which admits two (local) solutions in closed form belongs to type A 2-fold supersymmetry, irrespective of whether or not it is Hermitian, PT-symmetric, pseudo-Hermitian, and so on.Comment: 10 pages, no figures; typos correcte