Water-repellent and biocide treatments: Assessment of the potential combinations

It is a common practice to use several chemical products during restoration projects of monuments or sculptures. However, care must be taken when combining the products to avoid a misuse. For example, it is well-known that applying a biocide on stone before a water-repellent leads to a diminishment of the hydrophobic effect of the treatment. But the application of biocide after a water-repellent treatment has been poorly analysed, although studies have proven that the stone looses its hydrophobicity after the application of the biocide. Henceforth, this study investigates the effects of biocide application on a water-repellent film and focuses on the possibilities to restore the efficiency of the previous water-repellent treatment (after the application of the biocide). At first, the tests were performed on glass slides to understand the mechanisms, with the subsequent results revealing that the biocide product deposits on the water-repellent film. Then, the study focuses on determining methods to remove the remains of biocide on limestone samples, previously treated with a water-repellent. The water-repellent used in the study is an alkylpolysiloxane, Rhodorsil H224 from Rhodia.     

Changes in Mentor Efficacy and Perceptions Following Participation in a Youth Mentoring Program

Although mentoring programs are increasing in popularity as a preventative intervention strategy for youth, little is known about the experience from the mentor’s perspective. In this study, we describe a longitudinal assessment of 41 mentors, including 13 men and 28 women (M_age?=?21.93?years, SD?=?3.21) working with at-risk youth in a school-based mentoring program. Before starting the program, mentor perceptions, motives, and efficacy were assessed and again after three and six months of mentoring to measure change across time. At the end of the program, mentors evaluated the relationship and rated perceived benefits. Mentors experienced significant changes in perceptions and efficacy across time and changes predicted relationship satisfaction and perceived benefits. Recommendations to support mentors and develop sustainable and satisfying mentoring relationships are provided.     

“I learned by watching my mentor.” Nurturing teacher leadership with an induction program

ABSTRACT

How do educators learn to be teacher leaders? In this qualitative survey research study, we explored perceptions of 227 former induction program participants concerning teacher leadership (65% response rate). Methodologically, we conducted qualitative coding of open-ended survey data. Defined teacher leadership, participants often referred to their mentor. They reported currently serving in a wide variety of teacher leadership roles. They suggested the induction program and their mentors nurtured them to become teacher leaders. Examining the data, we conclude that during the program mentors demonstrate to novices teacher leader characteristics, as they share best practices, model professionalism, and offer support. They normalize that leadership is simply a part of good teaching. When the participants graduate and work in classrooms, many draw upon their induction experiences and emerge as teacher leaders. Data suggest that to increase teacher leadership, more comprehensive, full-time mentoring induction programs are warranted.     

What do plastics emit? HS-SPME-GC/MS analyses of new standard plastics and plastic objects in museum collections

In recent years, plastics are designated as a source of indoor pollution and particular attention has thus been devoted to the identification of emitting low molecular weight compounds. Headspace-solid phase microextraction-gas chromatography coupled with mass spectrometry (HS-SPME-GC/MS) has been already successfully applied for screening emissions from synthetic materials. This analytical tool being also non-invasive, it has been already successfully applied in the field of cultural heritage science for the identification of volatile organic compounds (VOCs) emitted from various museum objects made of natural materials. In this research, we aimed at assessing the use of HS-SPME-GC/MS as an in situ non-invasive analytical tool for a better knowledge of the volatile organic compounds emitted by plastics in collections. The possibility of characterizing plastics based on their emission signatures was also evaluated. Twelve new standard plastic samples, belonging to seven main polymer families widely present in museum collections as well as three naturally aged museum objects, were investigated. In this paper, we provide a survey of the VOCs emitted, and the use of HS-SPME-GC/MS for identifying volatile marker compounds, degradation products, additives, and monomer residues of the plastic synthesis is evaluated. More than 200 different VOCs were identified from the new standard samples. Two categories of VOCs were distinguished: “non-specific” and “specific” ones. We showed that based on the “specific” VOCs, it was possible to identify the nature of the polymeric matrix itself or at least to unambiguously distinguish a plastic by family. Emissions from the museum objects were then characterised, and main volatile degradation compounds considered as degradation markers of the natural deterioration of polymeric matrices, were identified. This identification procedure could be further exploited for the characterization of VOCs emitted by objects made of multiple synthetic polymers. Complementary to other techniques, this analytical tool is an interesting way to assess the risk for the objects stored in the vicinity of emitting plastics.     

Early Childhood Educators’ Use of Language-Support Practices with 4-Year-Old Children in Child Care Centers

The importance of encouraging language skills in early childhood has been well documented. Educators who are responsible for children in daycare services have many opportunities to use rich and stimulating educational practices that support language acquisition. The purpose of this study was to assess the language-support practices used by 22 educators in ECE centers with 174 children (87 girls and 87 boys) aged 55.7 months on average (SD = 4.2). The Teacher Interaction and Language Rating Scale developed by Girolametto et al. (Teacher interaction and language rating scale, Hanen Centre, Toronto, 2000) was translated and adapted for use in French. Analyses reveal the heterogeneity of language support provided to 4-year-old children attending early childhood education centers in Québec (Canada). Results are discussed in relation to the importance of the educational setting and specific training on language skill development provided to educators around promoting language skills in children, a fundamental prerequisite for educational success.     

Why students need to be prepared to cooperate: a cooperative nudge in statistics learning at university

Despite the potential benefits of cooperative learning at university, its implementation is challenging. Here, we propose a theory-based 90-min intervention with 185 first-year psychology students in the challenging domain of statistics, consisting of an exercise phase and an individual learning post-test. We compared three conditions that manipulated the exercise phase: individual work, cooperative dyadic instructions (structuring three basic components of cooperative learning: positive goal interdependence, individual responsibility and promotive interactions) and cooperative dyadic interactions (the three basic components with an additional cooperative nudge, namely explaining why and how to cooperate in this task) in order to test whether a progressive increase in benefits occurs as the cooperative structure is reinforced. Results indicated a linear trend in individual post-test learning and competence perception, from individual work to cooperative instructions to cooperative interactions. Competence perception mediated the effect of experimental conditions on learning. The results highlight the benefits of the cooperative nudge.     

Confocal XRF depth profiling non-destructively reveals the original blue pigments in a Renaissance painting by Caroto

Recent restoration of The Rest on the Flight into Egypt by Giovanni Francesco Caroto, from the Louvre collections, included a technical examination of the Virgin's blue robe that aimed to characterize the original materials and later additions. The painting was examined using light microscopy and ultraviolet and infrared imaging, and one cross section was taken. None of these methods showed a clear distinction between the layers that were artist applied or modifications made by another hand. To gain information about the paint stratigraphy without taking additional samples, non-invasive confocal X-ray fluorescence (CXRF) analysis was carried out to examine several areas of the Virgin's robe. Using this technique, it was possible to identify the pigments and order of application of paint by the artist. All the pigments identified were considered to be artist applied, and on this basis no further cleaning was carried out and conservation proceeded with retouching of minor areas of loss or damage. This study highlights the advantages of CXRF analysis for the technical study of paintings, used in combination with classical methods for making informed conservation treatment decisions.