Palaeolithic representations can be approached from different perspectives. Studying the creative processes, we can glimpse the decisions that the Palaeolithic artists made and the actions they carried out to materialize an idea. Additionally, the combined study of both graphic and functional actions performed on an object provides a comprehensive approach and understanding of the evidence: in the first place, it allows us to hypothesize about the presence or absence of symbolic purpose of the representations; secondly, it makes the potential choice of eliminating such symbolism discernible for us. The monographic study of a Magdalenian pebble from Coímbre Cave (Asturias, Spain) engraved between 15,680 and 14,230 cal. bp shows that a mistake was made during the engraving process; subsequently an attempt was made to eliminate the representations, and finally the pebble was used as a hammerstone. This paper provides argumentation to reconstruct a complex biography of an object of Palaeolithic portable art, discussing intentional loss of symbolic value of both the decoration and the object and the latter's reuse (as raw material) for an economic or domestic purpose.

We use the SPace Infrared telescope for Cosmology and Astrophysics (SPICA) project as a template to demonstrate how deep spectrophotometric surveys covering large cosmological volumes over extended fields (1– $15\, \rm{deg^2}$ ) with a mid-IR imaging spectrometer (17– $36\, \rm{\rm{\upmu m}}$ ) in conjunction with deep $70\, \rm{\rm{\upmu m}}$ photometry with a far-IR camera, at wavelengths which are not affected by dust extinction can answer the most crucial questions in current galaxy evolution studies. A SPICA-like mission will be able for the first time to provide an unobscured three-dimensional (3D, i.e. x, y, and redshift z) view of galaxy evolution back to an age of the universe of less than $\sim$ 2 Gyrs, in the mid-IR rest frame. This survey strategy will produce a full census of the Star Formation Rate (SFR) in the universe, using polycyclic aromatic hydrocarbons (PAH) bands and fine-structure ionic lines, reaching the characteristic knee of the galaxy luminosity function, where the bulk of the population is distributed, at any redshift up to $z \sim 3.5$ . Deep follow-up pointed spectroscopic observations with grating spectrometers onboard the satellite, across the full IR spectral range (17– $210\, \rm{\rm{\upmu m}}$ ), would simultaneously measure Black Hole Accretion Rate (BHAR), from high-ionisation fine-structure lines, and SFR, from PAH and low- to mid-ionisation lines in thousands of galaxies from solar to low metallicities, down to the knee of their luminosity functions. The analysis of the resulting atlas of IR spectra will reveal the physical processes at play in evolving galaxies across cosmic time, especially its heavily dust-embedded phase during the activity peak at the cosmic noon ( $z \sim 1$ –3), through IR emission lines and features that are insensitive to the dust obscuration.

Using an ensemble of close- and long-range remote sensing, lake bathymetry and regional meteorological data, we present a detailed assessment of the geometric changes of El Morado Glacier in the Central Andes of Chile and its adjacent proglacial lake between 1932 and 2019. Overall, the results revealed a period of marked glacier down wasting, with a mean geodetic glacier mass balance of −0.39 ± 0.15 m w.e.a−1 observed for the entire glacier between 1955 and 2015 with an area loss of 40% between 1955 and 2019. We estimate an ice elevation change of −1.00 ± 0.17 m a−1 for the glacier tongue between 1932 and 2019. The increase in the ice thinning rates and area loss during the last decade is coincident with the severe drought in this region (2010–present), which our minimal surface mass-balance model is able to reproduce. As a result of the glacier changes observed, the proglacial lake increased in area substantially between 1955 and 2019, with bathymetry data suggesting a water volume of 3.6 million m3 in 2017. This study highlights the need for further monitoring of glacierised areas in the Central Andes. Such efforts would facilitate a better understanding of the downstream impacts of glacier downwasting.

We present a detailed overview of the cosmological surveys that we aim to carry out with Phase 1 of the Square Kilometre Array (SKA1) and the science that they will enable. We highlight three main surveys: a medium-deep continuum weak lensing and low-redshift spectroscopic HI galaxy survey over 5 000 deg2; a wide and deep continuum galaxy and HI intensity mapping (IM) survey over 20 000 deg2 from $z = 0.35$ to 3; and a deep, high-redshift HI IM survey over 100 deg2 from $z = 3$ to 6. Taken together, these surveys will achieve an array of important scientific goals: measuring the equation of state of dark energy out to $z \sim 3$ with percent-level precision measurements of the cosmic expansion rate; constraining possible deviations from General Relativity on cosmological scales by measuring the growth rate of structure through multiple independent methods; mapping the structure of the Universe on the largest accessible scales, thus constraining fundamental properties such as isotropy, homogeneity, and non-Gaussianity; and measuring the HI density and bias out to $z = 6$ . These surveys will also provide highly complementary clustering and weak lensing measurements that have independent systematic uncertainties to those of optical and near-infrared (NIR) surveys like Euclid, LSST, and WFIRST leading to a multitude of synergies that can improve constraints significantly beyond what optical or radio surveys can achieve on their own. This document, the 2018 Red Book, provides reference technical specifications, cosmological parameter forecasts, and an overview of relevant systematic effects for the three key surveys and will be regularly updated by the Cosmology Science Working Group in the run up to start of operations and the Key Science Programme of SKA1.

The timing of the late Middle Paleolithic and late disappearance of Neanderthals in the Iberian Peninsula are hotly debated subjects in Paleolithic archeology. Several studies suggested a late survival in South and Central Iberia until about 32 ka, but were probably subject to significant age underestimation due to contamination of dating samples, undiagnostic lithic assemblages, and/or lack of stratigraphic integrity. We conducted a radiocarbon and luminescence-dating study backed by detailed sedimentological and micromorphological investigations at the newly discovered rock shelter sequence of Abrigo del Molino (Central Spain). Accumulation of the sediment sequence was rapid. It started with deposition of paleoflood slack-water deposits at around 48 ka and continued until about 41 ka with deposition of colluvial and detrital sediments. These contain two Mousterian levels, which place the latest Neanderthal occupation at around 45 to 41 ka, i.e., between Heinrich Stadials 5 and 4, and probably during a time of climate amelioration. Abrigo del Molino thus provides a detailed and chronologically well-constrained record of Late Neanderthal presence and morphodynamic change in Central Iberia during times of millennial-scale climate changes. The site gives further evidence for an early disappearance of Neanderthals in Central Iberia.

The main objective was to analyze relationships and predictive patterns between 3x2 classroom goal structures (CGS), and motivational regulations, dimensions of self-concept, and affectivity in the context of secondary education. A sample of 1,347 secondary school students (56.6% young men, 43.4% young women) from 10 different provinces of Spain agreed to participate (M age = 13.43, SD = 1.05). Hierarchical regression analyses indicated the self-approach CGS was the most adaptive within the spectrum of self-determination, followed by the task-approach CGS. The other-approach CGS had an ambivalent influence on motivation. Task-approach and self-approach CGS predicted academic self-concept (p < .01; p < .001, respectively; R2 = .134), and both along with other-approach CGS (negatively) predicted family self-concept (p < .05; p < .001; p < .01, respectively; R2 = .064). Physical self-concept was predicted by the task-approach and other-approach CGS’s (p < .05; p < .001, respectively; R2 = .078). Finally, positive affect was predicted by all three approach-oriented CGS’s (p < .001; R2 = .137), whereas negative affect was predicted by other-approach (positively) and self-approach (negatively) CGS (p < .001; p < .05, respectively; R2 = .028). These results expand the 3x2 achievement goal framework to include environmental factors, and reiterate that teachers should focus on raising levels of self- and task-based goals for students in their classes.

The spatial and orientational distribution in a dilute active suspension of non-Brownian run-and-tumble spherical swimmers confined between two planar hard walls is calculated theoretically. Using a kinetic model based on coupled bulk/surface probability density functions, we demonstrate the existence of a concentration wall boundary layer with thickness scaling with the run length, the absence of polarization throughout the bulk of the channel, and the presence of sharp discontinuities in the bulk orientation distribution in the neighbourhood of orientations parallel to the wall in the near-wall region. Our model is also applied to calculate the swim pressure in the system, which approaches the previously proposed ideal-gas behaviour in wide channels but is found to decrease in narrow channels as a result of confinement. Monte Carlo simulations are also performed for validation and show excellent quantitative agreement with our theoretical predictions.

A new generation of radio telescopes with unprecedented capabilities for astronomy and fundamental physics will be in operation over the next few years. With high sensitivities and large fields of view, they are ideal for cosmological applications. We discuss their uses for cosmology focusing on the observational technique of HI intensity mapping, in particular at low redshifts (z < 4). This novel observational window promises to bring new insights for cosmology, in particular on ultra-large scales and at a redshift range that can go beyond the dark energy domination epoch. In terms of standard constraints on the dark energy equation of state, telescopes such as Phase I of the SKA should be able to obtain constrains about as well as a future galaxy redshift surveys. Statistical techniques to deal with foregrounds and calibration issues, as well as possible systematics are also discussed.

The reform of the pension system of the Mexican Social Security Institute (IMSS) in 1997, limited the growing fiscal cost of the previous pay-as-you-go scheme. Sixteen years on from its creation, the Retirement Savings System (SAR) has had favourable macroeconomic effects for Mexico, as it has significantly increased financial savings and encouraged the development of local financial markets.

However, the employment and pension coverage has not developed as hoped, due to the high rate of informality in the labour market. In addition, the replacement rates (RR) forecast for old-age pensions from the defined-contribution scheme will be low, due to problems exogenous to the pension system, such as low contribution rates and low contribution densities. The main objective of this study is to develop a macroeconomic and actuarial projection model to simulate the expected coverage and RR for the period 2012–2050, within the framework of a demographic and economic forecast that will allow a detailed diagnosis of the current conditions of the pension system. The results reveal the unpromising scenario that the pension system has and will continue to have in the long term, with limited improvements in coverage rates. The possibility of obtaining adequate pensions will be restricted to those who have socioeconomic conditions with a long employment history, who can thus make contributions to their individual accounts.

Taking into account this baseline projection scenario, we simulate the expected effects of applying a set of proposals with the aim of tackling the main problems, such as the low coverage, low RR, and low level of participation by young people in the system.