967 research outputs found
Weathering Processes on Sandstone Painting and Carving Surfaces at Prehistoric Rock Sites in Southern Spain
The sandstones which constitute the host rock for the prehistoric artwork in the Rock Groups of Tajo de las Figuras and Peñas de Cabrera (southern Spain) show a serious degree of alteration, due both to natural processes and those related to anthropogenic and animal activity. A detailed study was carried out on the petrological and compositional characteristics of the sandstones (fresh and altered rock) in both rock groups, and on the geological and climatological characteristics of the area in which they are located. The sandstones have very similar petrological and compositional characteristics in both areas. This likeness causes the nature of the natural weathering processes to be similar in the rock areas studied. These processes can be divided in terms of the predominant mechanisms of alteration into three inter-related categories: mechanical weathering, chemical weathering, and bio-induced alteration processes. However, the different climatic conditions of the areas in which the two rock areas are located directly influences the intensity of these processes. The precipitation and the range of temperature variation with heavy winter frosts in the area of El Tajo de las Figuras are significantly higher than in the area of Peñas de Cabrera; this translates into a higher rate of weathering at El Tajo de las Figuras. Regarding the anthropogenic action, two types of influence on the deterioration can be distinguished: a direct one, which consists of scouring and wetting of the walls in order to increase the chromatic contrast; and an indirect one, which is the extraction of blocks of sandstone in the upper part of rock shelters, which in turn encourages the development of the chemical weathering processes.This study forms part of the research agreement “Study and diagnosis of the archaeological groups and deposits of the Autonomous Community of Andalusia in their geomorphological, biological and climatic contexts” financed by the Culture Council, Junta of Andalusia (Spain)
Histone Mutants Separate R Loop Formation from Genome Instability Induction
R loops have positive physiological roles, but they can also be deleterious by causing genome instability, and the mechanisms for this are unknown. Here we identified yeast histone H3 and H4 mutations that facilitate R loops but do not cause instability. R loops containing single-stranded DNA (ssDNA), versus RNA-DNA hybrids alone, were demonstrated using ssDNA-specific human AID and bisulfite. Notably, they are similar size regardless of whether or not they induce genome instability. Contrary to mutants causing R loop-mediated instability, these histone mutants do not accumulate H3 serine-10 phosphate (H3S10-P). We propose a two-step mechanism in which, first, an altered chromatin facilitates R loops, and second, chromatin is modified, including H3S10-P, as a requisite for compromising genome integrity. Consistently, these histone mutations suppress the high H3S10 phosphorylation and genomic instability of hpr1 and sen1 mutants. Therefore, contrary to what was previously believed, R loops do not cause genome instability by themselves.European Research Council ERC2014 AdG669898Ministerio de Economía y Competitividad BFU2013-42918-P, BFU2016-75058-
Spontaneous Magnetization in Heterometallic NiFe-MOF-74 Microporous Magnets by Controlled Iron Doping
We report the direct synthesis of mixed-metal NiFe-MOF-74 solids that display combination of porosity with ferrimagnetic ordering. Compared to the undoped Ni phase, controlled doping with Fe enables to modify intra and interchain magnetic interactions for the onset of spontaneous magnetization at temperatures fixed by the doping level. Synthesis of porous magnets remains somewhat elusive due to the difficulties in isolating foreseeable metal-organic architectures that combine small bridging linkers, for strong magnetic coupling, with polyaromatic connectors responsible for porosity. In turn, we demonstrate that metal doping is better fitted to modify the magnetism of Metal-Organic Frameworks already available simply by suitable choice of their nature and relative ratio in isostructural solid solutions
Helping others helps me: prosocial behavior and satisfaction with life during the COVID-19 pandemic
[ES] Prosocial behavior (PsB) and its effects have been analyzed in times of crisis and natural disasters, although never before in the face of such exceptional circumstances as those created by the COVID-19 pandemic. This research analyzes the role of PsB on satisfaction with life (SWL) in Colombia, considering the negative emotional impact of events that began in February 2020. We conduct an exploratory analysis using a sample of Colombia’s general population (N = 2,574; 53.2% women) with an average age of 44.66 years (SD = 15.36). Using the Classification Tree technique, we find that engaging in one or more PsBs (e.g., donating money or sharing food) enhances SWL and decreases the impact of negative emotions such as pessimism, indecisiveness, and irritability that have emerged during the COVID-19 pandemic. These findings are significant because they confirm the importance of life satisfaction as a personal resource for coping with complex situations and provide evidence of the benefits of PsB on one’s wellbeing
Analysis of construction accidents in Spain, 2003-2008
The research objective for this paper is to obtain a new extended and updated insight to the likely causes of construction accidents in Spain, in order to identify suitable mitigating actions. Method: The paper analyzes all construction sector accidents in Spain between 2003 and 2008. Ten variables were chosen and the influence of each variable is evaluated with respect to the severity of the accident. The descriptive analysis is based on a total of 1,163,178 accidents. Results: Results showed that the severity of accidents was related to variables including age, CNAE (National Classification of Economic Activities) code, size of company, length of service, location of accident, day of the week, days of absence, deviation, injury, and climatic zones. Conclusions: According to data analyzed, a large company is not always necessarily safer than a small company in the aspect of fatal accidents, experienced workers do not have the best accident fatality rates, and accidents occurring away from the usual workplace had more severe consequences. Impact on the industry: Results obtained in this paper can be used by companies in their occupational safety strategies, and in their safety training programs
An Evolutionary Artificial Neural Network approach for spatio-temporal wave height time series reconstruction
This paper proposes a novel methodology for recovering missing time series data, a crucial task for
subsequent Machine Learning (ML) analyses. The methodology is specifically applied to Significant
Wave Height (SWH) time series in the field of marine engineering. The proposed approach involves two
phases. Firstly, the SWH time series for each buoy is independently reconstructed using three transfer
function models: regression-based, correlation-based, and distance-based. The distance-based transfer
function exhibits the best overall performance. Secondly, Evolutionary Artificial Neural Networks
(EANNs) are utilised for the final recovery of each time series, using as inputs highly correlated buoys
that have been intermediately recovered. The EANNs are evolved considering two metrics, the novel
squared error relevance area, which balances the importance of extreme and around-mean values, and
the well-known mean squared error. The study considers SWH time series data from 15 buoys in two
coastal zones in the United States. The results demonstrate that the distance-based transfer function
is generally the best transfer function, and that EANNs outperform a range of state-of-the-art ML
techniques in 12 out of the 15 buoys, with a number of connections comparable to linear models.
Furthermore, the proposed methodology outperforms the two most popular approaches for time
series reconstruction, BRITS and SAITS, for all buoys except one. Therefore, the proposed methodology
provides a promising approach, which may be applied to time series from other fields, such as wind
or solar energy farms in the field of green energy
Seeing topological edge and bulk currents in time-of-flight images
5 pags., 5 figs.Here we provide a general methodology to directly measure the topological currents emerging in the optical lattice implementation of the Haldane model. Alongside the edge currents supported by gapless edge states, transverse currents can emerge in the bulk of the system whenever the local potential is varied in space, even if it does not cause a phase transition. In optical lattice implementations the overall harmonic potential that traps the atoms provides the boundaries of the topological phase that supports the edge currents, as well as providing the potential gradient across the topological phase that gives rise to the bulk current. Both the edge and bulk currents are resilient to several experimental parameters such as trapping potential, temperature, and disorder. We propose to investigate the properties of these currents directly from time-of-flight images with both short-time and long-time expansions.This work was supported by the EPSRC Grant No.
EP/R020612/1; Spanish Projects PGC2018-094792-B-I00
(MCIU/AEI/FEDER, EU), PGC2018-094180-B-I00 (MCIU
/AEI/FEDER, EU), and FIS2015-63770-P (MINECO
/FEDER, EU); CAM/FEDER Project No. S2018/TCS-4342
(QUITEMAD-CM), and CSIC Research Platform PTI-001
Correspondence Model Of Occupational Accidents
We present a new generalized model for the diagnosis and prediction of accidents among the Spanish workforce. Based on observational data of the accident rate in all Spanish companies over eleven years (7,519,732 accidents), we classified them in a new risk-injury contingency table (19x19). Through correspondence analysis, we obtained a structure composed of three axes whose combination identifies three separate risk and injury groups, which we used as a general Spanish pattern. The most likely or frequent relationships between the risk and injuries identified in the pattern facilitated the decision-making process in companies at an early stage of risk assessment. Each risk-injury group has its own characteristics, which are understandable within the phenomenological framework of the accident. The main advantages of this model are its potential application to any other country and the feasibility of contrasting different country results. One limiting factor, however, is the need to set a common classification framework for risks and injuries to enhance comparison, a framework that does not exist today. The model aims to manage work-related accidents automatically at any level
- …