Exfoliation microcracks in building granite. Implications for anisotropy

Granite is found in many world heritage monuments and cities. It continues to be one of the most widely used stones in today's construction, given its abundance, uniformity and durability. Quarrymen traditionally cut this rock along its orthogonal slip planes, where splitting is easier. Ranked by ease of splitting, these planes are rift, grain and hardway. Granite is traditionally quarried along the rift plane where coplanar exfoliation microcracks coalesce developing a flat surface. This splitting surface minimizes the cost and effort of subsequent hewing. Rift plane was predominantly used on the fair face of ashlars in heritage buildings worldwide. Determining the petrographic and petrophysical behaviour of these three orthogonal splitting planes in granite is instrumental to understanding decay in ashlars and sculptures. The decay of building granite is different in each splitting plane. Alpedrete granite was the stone selected for this study based on the orientation and distribution of exfoliation microcracks and the characterisation of their implications for the anisotropy of petrophysical properties such as ultrasonic wave propagation, capillarity, air permeability, micro-roughness and surface hardness. Inter- and intracrystalline microcrack length and spacing were also measured and quantified. The findings show that the splitting planes in Alpedrete granite are determined by the orientation of exfoliation microcracks, which as a rule are generally straight and intracrystalline and determine the anisotropy of the petrophysical properties analysed. Splitting planes are the orientation that should be applied when performing laboratory tests for the petrographic and petrophysical properties of building granite.This study was funded by the Regional Government of Madrid, Spain, in the framework of the GEOMATERIALS-2CM [S2013/MIT-2914] programme.Peer reviewe

Thermal stress-induced microcracking in building granite

Microcracking induced by wide fluctuations in temperature affects granite quality and durability, making the stone more vulnerable to decay. Determining the extent of that effect is not always straightforward, however, given the excellent durability of these materials. Four types of construction granite quarried in the region of Madrid, Spain, and frequently used in both the built heritage and in de novo construction (Alpedrete, Cadalso de los Vidrios, Colmenar Viejo and Zarzalejo) were exposed to 42 thermal cycles (105–20 °C; UNE-EN, 14066, 2003). Petrographic and petrophysical properties were analysed using both destructive and non-destructive techniques. Microcracking generated in the granite stones by 42 thermal cycles had barely any impact on their petrophysical properties, which are the parameters normally assessed to establish material quality and durability. Their petrographic properties, which are not generally assessed in this type of studies, were affected, however. This study contends that petrographic analysis is needed to objectively quantify the actual quality and durability of the most highly resistant materials when petrophysical studies are inconclusive. Petrographic and fluorescence microscopy, along with fractography, are among the most prominent techniques for petrographic exploration. Thanks to the deployment of these techniques, mineral microcracking could be monitored throughout the present tests conducted. The microscopic findings revealed substantial micro-textural and microstructural change in and around the granite minerals, which play a prominent role in decay. The findings showed that pre-existing microcracks coalesced and generated further microcracking as decay progressed. Microcracking was most intense in Zarzalejo granite due to its textural characteristics determined by its high feldspar content. Microscopic observation revealed that the microstructure of feldspar minerals, with their crystallographic anisotropies and secondary mineral phases, favoured microcrack development. Zarzalejo granite exhibited lower quality and durability than Colmenar Viejo and Cadalso de los Vidrios granites, which were more resistant to heat treatment.This study was funded by the project GEOMATERIALES 2 (S2013/MIT-2914).Peer reviewe

Causes of scaling on bush-hammered heritage ashlars: a case study—Plaza Mayor of Madrid (Spain)

Masons have traditionally used granite anisotropy to cut and lay the stone. Scaling, a common type of granite decay, is observed worldwide. This study explored the relationship between weathering and cut planes in heritage ashlars, specifically in the stone on Madrid’s Plaza Mayor, whose construction dates back to 1590. The 71 rectangular granite columns that support its porticoes are oriented towards the four cardinal points. All 71 have one exposed side that faces the square, one protected side facing inward and two semi-protected sides perpendicular to the other two. The sides of the columns are also oriented to the points of the compass. This study aimed to identify the prevailing orientation of scaling, if any, in the granite ashlars and to determine how this process is affected by climate, microclimate (orientation), use, hewing and exfoliation microcracks. All four sides of the 71 columns were mapped (284 in all) to analyse scaling height, distribution and orientation. The findings showed that the microcracks are vertically oriented and decline in density and length with depth from the surface. Scaling was observed on the lower ashlars in the columns to a maximum depth of 3 mm. Determining the direction of exfoliation microcracks is imperative to understanding decay mechanisms in granite ashlars and sculptures and that information must be taken into consideration when applying conservation treatments.This study was funded by the Community of Madrid under the GEOMATERIALS (S2009/MAT-1629) and GEOMATERIALS-2CM (S2013/MIT-2914) research programmes and Project 921349 awarded to the Complutense University of Madrid’s Research Group ‘Alteración y Conservación de los Materiales Pétreos del Patrimonio’Peer reviewe

Damage in the Cadalso de los Vidrios Granite under water freeze/thaw conditions

The repeated action of simulated freeze-thaw cycles on Cadalso de los Vidrios Granite, promotes differential micro-cracking and loss of cr ystals at the surface and therefore decay. It is possible to establish a relationship between the evolution of the ultrasound waves velocity (Vp) with the number of freeze-thaw cycles and the generation of microcracks. Intergranular cracks are formed during the first cycles and these propagate towards the inner part of each individual crystals as the freeze-thaw cycles advance. Therefore, after 280 freeze-thaw cycles different patterns of microcracking can be observed depending on the mineralogy. Quartz is the mineral displaying more intense cracking while biotite shows less cracking, in part due to its more ductile behaviour. Micro-cracks appear preferentially at the surface of the samples with a maximum length and depth of 1 cm. Thus, these samples showed limited decay highlighting the good performance of Cadalso de los Vidrios granite against freezethaw.Peer reviewe

Self-Regulation and Students Well-Being: A Systematic Review 2010–2020

This article belongs to the Section Psychology of Sustainability and Sustainable Development[Abstract] In recent years, there has been particular interest in studying the relationship between student self-regulation and variables such as students’ well-being, satisfaction, and school engagement. Although in other fields such as healthcare, self-regulation in different areas seems to influence individuals’ well-being, this is not so well established in the educational arena. We performed a systematic search of research articles published between 2010 and 2020 which explored the relationships between self-regulation and student well-being. The present article presents a report of a systematic review of 14 research articles. The analysis showed that some executive functions and self-regulation strategies employed in the learning process, and some self-regulatory deficits are significantly associated with different dimensions of student well-being.This research was funded by Deputación Provincial de A Coruña through The Research Grants Program 2021 in social and legal sciences. Grant number: 2021000025393, FPI Program of the Ministry of Science, Innovation and Universities (PRE2018-084938) and Xunta de Galicia (Consellería de Cultura, Educación y Universidad) under a predoctoral fellowship [ED481A 2021/351]Deputación Provincial de A Coruña; 2021000025393Xunta de Galicia; ED481A 2021/35

Prothymosin α is phosphorylated by casein kinase-2

AbstractProthymosin α (ProTα) is a 12.5 kDa acidic polypeptide that is considered to have a nuclear function related to cell proliferation. Inspection of its amino acid sequence revealed the presence of sequences that may serve as targets for phosphorylation by casein kinase-2 (CK-2). ProTα isolated from calf thymocytes was phosphorylated in vitro by CK-2. The phosphorylation sites are Ser and Thr residues located among the first 14 amino acid residues in the ProTα sequence. Another site that is theoretically suitable for phosphorylation by CK-2, at the C-terminus of the polypeptide, is not, in fact, phosphorylated. Thymosin α1 (Tα1), a peptide whose sequence corresponds to the first 28 amino acids of ProTα, is also phosphorylated by CK-2 at the same phosphorylation sites as ProTα. In cultured splenic lymphocytes ProTα was phosphorylated at Thr residues located at positions 7, 12 and/or 13. Based on these observations we conclude that CK-2, or another cellular kinase with similar sequence specifity, is responsible for phosphorylation of ProTα in vivo

COVID-19 Lockdown: Key Factors in Citizens’ Stress

[Abstract] Background: Confinement due to COVID-19 can have a short‐ and long-term impact on mental health (increased levels of stress and anxiety and emotional upheaval) and on people’s quality of life. Knowing what factors are behind the stress can benefit the development of strategies and resources for future situations of a similar nature. The purpose of this study is to examine the incidence of a series of sociodemographic factors, confinement conditions, and work situation on the stress reported by confined citizens. Method: The sample is made up of 2008 citizens (19.9% men), the Perceived Stress Scale of 14 items (PSS-14) was used to assess the stress level of the population, as well as a sociodemographic questionnaire and different questions aimed at obtain information about the characteristics of the confinement and the employment situation. Data were collected using exponential snowball-type non-probability sampling. Results: The results suggest that sociodemographic factors such as age, gender, and income level could be good predictors of confinement stress. Post-confinement work expectancy along with pre-confinement working conditions can be key to protecting the well-being of confined populations. Limitations: This is a transversal study that forces us to be cautious with causal interpretations. The questionnaire was administered online, which means it excluded a good proportion of the population. Conclusion: The perception of stress being higher in women than men, with the lowest stress in older people and those with higher reported incomes. Stress levels increase as populations spend more weeks in confinement and the pre-confinement work situation seems key to protecting the well-being of the population. A lower stress is observed among stable couples without children confined in residential or suburban areas. Low income or economic instability is associated with a higher rate of stress and anxiety. The results can contribute to prioritizing actions and aid by contributing to the formation of teams and the design of tools for work in the current pandemic situation.This study was funded by the research project EDU2013-44062-P (MINECO) and EDU2017-82984-P (MEIC) and the FPU program (FPU18/02191) and the FPI program (PRE2018-084938) from the Ministry of Science, Innovation, and Universities to two of the author

Genome sizes and karyotypes in the razor clams "Ensis arcuatus" (Jeffreys, 1865) and "E. siliqua" (Linnaeus, 1758)

[Abstract] The razor clams Ensis arcuatus and E. siliqua show a diploid DNA content of 3.85 ± 0.049 pg and 4.00 ± 0.050 pg, respectively. Both have a diploid chromosome number of 38 although their karyotypes show remarkable differences. The karyotype of E. arcuatus consists of 4 metacentric, 1 metacentric-submetacentric, 7 submetacentric and 7 telocentric chromosome pairs, whereas that of E. siliqua possesses 3 metacentric, 7 submetacentric and 9 telocentric pairs. In situ hybridization using an 18S-5.8S-28S rDNA probe located this ribosomal locus on one chromosome pair for both species. Results demonstrate that large differences exist between them, probably caused by chromosome rearrangements along evolution of these two species, and increase the number of studies on bivalve cytogenetics.Xunta de Galicia; PGIDT99 MAR1030

How to deal with invasive species that have high economic value?

The ever-accelerating process of introduction and establishment of invasive alien species (IAS) in marine waters requires engaging different actors in the management and planning. To address this challenge, stakeholders need an integrated approach for defining actions of control and management within an ecosystem-based framework: to seek and enhance coordination, collaboration and trust among all stakeholders affected by changes in linked marine social - ecological systems. This study explores the complexities and opportunities in managing economically valuable IAS, demonstrating the need for tailored management strategies that consider key ecological details needed for successful control such as timing of removals and key economic considerations such as appropriate incentive mechanisms and time horizons in favor of long-term conservation goals. We propose a set of actions that can serve as a roadmap for effective IAS control and management, considering their dual role as nuisances and valuable resources. These actions pertain to local, regional and international levels, encouraging meaningful stakeholder engagement through co-management structures that can foster the development of robust management plans, enabling better IAS control. The outcome holds potential for positive contributions to the blue economy— sustainable use of marine resources, including fisheries, tourism, and renewable energy— and for meeting sustainability objectives