Dimensional Stability and Moisture Properties of Gap-Fillers Based on Wood Powder and Glass Microballoons

ABSTRACT

Conservation of wooden objects exposed outdoors is extremely difficult and complex due to their constant exposure to fluctuating weather conditions and biological degradation. Filling the gaps in such objects requires the use of specific materials that in particular can adapt to changes in wood dimensions in response to humidity variations. Various materials have been used so far for filling voids in wooden artefacts but none of them was entirely suitable. Therefore, the authors have attempted to provide the basic characteristics of the selected commonly used filling materials based on pine wood powder or glass microballoons as fillers and Paraloid® B-72, Klucel® G, or glutin glue as binders, as the first step in research aiming at developing new and more appropriate gap-fillers. Special attention was paid to the dimensional stability of filling materials upon drying and exposure to water vapour and liquid water. The overall results indicate that among the examined fills those consisting of Paraloid® B-72 and glass microballoons revealed best properties as they were relatively dimensionally stable upon drying and exposure to moisture – despite high absorption of water – and were quite easy to finish. Generally, better properties were observed for filling materials containing higher concentrations of adhesives and these materials will be modified in the next step of the research. Since the main drawbacks of the examined gap-fillers were low water resistance, poor dimensional stability upon drying or exposure to water vapour or liquid water, and fragility or friability, future research into their modification will head towards improvement of the above-mentioned properties.     

An Introduction to Distributions Using Weighted Dice

This article describes a lively classroom demonstration that may be used to help develop students' understanding of the concept of a distribution, and to provide a foundation for the intuitive link between distributions and hypothesis testing.     

Metacognitive experience on Raven’s matrices versus insight problems

Metacognition and Learning - Participants rated Intuition, Suddenness, Pleasure, and Certainty accompanying their solutions to items of a popular fluid intelligence test – Raven’s...     

Keith Pavitt and the Invisible College of the Economics of Technology and Innovation

This paper uses a database on scientific interaction in the field of the economics of technological change and innovation. The database is used to address two issues. First, the network is shown to be (approximately) scale-free. This suggests that growth of the number of scholars active in the field and so-called preferential attachment (i.e., scholars entering the field prefer to attach themselves to highly reputable existing members of the network) are characteristic of the nature of the underlying field. Thus, increasing returns seem to govern mechanisms of reputation formation. Second, the potential existence of cohesive subgroups of relatively strongly connected scholars is explored, and the implications of this for the paradigmatic structure of the field are discussed.     

Network embeddedness and the exploration of novel technologies: Technological distance, betweenness centrality and density

This paper aims to understand better the innovation potential of a firm’s alliance network. Here we analyze the role of an alliance network in terms of the technological distance between partners, a firm’s network position (centrality) and total network density. We study how these three elements of an alliance network, separately and in combination, affect the ‘twin tasks’ in exploration, namely novelty creation on the one hand and its efficient absorption on the other hand. For an empirical test, we study technology-based alliance networks in the pharmaceutical, chemical and automotive industries. Our findings indicate that successful exploration indeed seems to require a delicate balance between these two exploration tasks. A second conclusion is that different network positions yield different pay-offs in terms of the number of explorative patents. In other words, success rates for exploration are not spread equally across firms. However, position alone does not tell the full story. Our empirical findings clearly indicate that exploration success also depends on the other two dimensions of embeddedness, namely technological distance and network density. The three elements of network embeddedness need to be considered jointly in order to understand their complementary effects on both novelty creation and absorptive capacity.     

Inside the source selection process: Selection criteria for human information sources

Co-workers are an important source of information in organizations. Consequently, information managers seek to facilitate the use of such human information sources. Although various studies about what influences the use of human information sources in organizations exist, it is difficult for information managers to utilize insights from this research body. The studies have provided contradictory results regarding the role of accessibility and quality and suffer from various weaknesses. To address these weaknesses, several studies are employing other research methods. This study aims to contribute to the methodological development of this emerging new line of research by exploring the value of a think aloud approach to such studies. In addition, it aims to provide more insight into the role of accessibility and quality in the selection of human information sources in organizations. Fifty-six employees from four governmental organizations were asked to think aloud while selecting human information sources. The findings of this study corroborate those of studies taking a similar approach: source quality is the most dominant factor in the selection of human information sources. The think aloud approach seems a valuable contribution to available research methods to assess the role of accessibility and quality in human source selection in organizations.     

Low-dose exercise training does not influence cardiac autonomic control in healthy sedentary men aged 55-75 years

The purpose of this study was to evaluate the effects of a realistic, feasible, and commonly used fitness training programme on cardiac autonomic control in 14 sedentary men aged 62.0 +/- 6.1 years (mean +/- s). All participants performed a one-year fitness training programme in which training intensity and frequency were specifically chosen to be compliant for the majority of the participants (2-3 sessions per week at moderate intensity). At the same time, a reference group consisting of 15 sedentary age-matched men (age 64.2 +/- 6.5 years) did not change their habitual physical activity. Measurements were performed before and after the training intervention. Cardiac autonomic control was inferred from resting values (supine and standing) of heart rate variability (HRV) computed in the frequency domain over 10-min intervals. Endurance capacity was evaluated during a maximal incremental bicycle ergometer test. In spite of an increase in peak oxygen consumption (VO2peak) by 6.4% after training, heart rate in the training group remained unchanged at rest and at the same metabolic demand. No changes in resting parameters of HRV were shown for either groups or positions. Results from this study provide no evidence of a clinically meaningful increase in the vagal modulation to the sinus node at rest after one year of low-volume and moderate-intensity fitness training in men aged 55-75 years.     

How well-being and involvement fit into the commitment to children’s rights

The theme of children’s rights is receiving more attention than ever procedures. Although the manifest on this topic was universally agreed decades ago, it is obvious that the ambitions expressed in it are far from being implemented. In this article, we explore how the experiential approach can contribute to the process of clarification and operationalisation for children between birth and the age of six. The central idea is that well-being and involvement as process variables can provide a measure for the degree to which children’s rights are met, especially in educational settings. The scanning and screening are highlighted as procedures to assess levels of well-being and involvement. The data yielded provide a rich source for interventions both at the individual and group level. Next, we review what we can learn from research where these process-variables have been observed, that is their levels and the factors in the (learning) environment that determine them. In the closing discussion, we hold the insights on well-being and involvement against the light of “children’s rights” and articulate implications for practice, research and policy.     

Gender influence on the adaptation of atrial performance to training

Background: High-intensity training has been associated with atrial remodelling and arrhythmias in men. Our purpose was to analyse atrial performance in female endurance athletes, compared to male athletes and controls. Methods: This was a cross-sectional study. We included four groups: female athletes, females controls, male athletes and male controls. Left (LA) and right atrial (RA) volumes and function were assessed using 2D and speckle-tracking echocardiography to determine peak atrial strain-rate at atrial (SRa) and ventricular contraction (SRs), as surrogates of atrial contractile and reservoir function, respectively. ANOVA and Bonferroni’s statistical tests were used to compare variables among groups. Results: We included 82 subjects, 39 women (19 endurance athletes, 20 controls) and 43 men (22 endurance athletes, 21 controls). Mean age was similar between groups (36.6?±?5.6 years). Athletes had larger bi-atrial volumes, compared to controls (women, LA 27.1 vs. 15.8?ml/m², p?<?0.001; RA 22.31 vs. 14.2?ml/m², p?=?0.009; men, LA: 25.0 vs. 18.5?ml/m², p?=?0.003; RA 30.8 vs. 21.9?ml/m², p?<?0.001) and lower strain-rate (women, LASRa ?1.60 vs. ?2.18?s^?1, p?<?0.001; RASRa ?1.89 vs. ?2.38?s^?1, p?=?0.009; men, LASRa ?1.21 vs. ?1.44?s^?1, p?=?1; RASRa ?1.44 vs. ?1.60?s^?1, p?=?1). However, RA indexed size was lower and bi-atrial deformation greater in female athletes, compared to male athletes. Conclusions: The atria of both male and female athletes shows specific remodelling, compared to sedentary subjects, with larger size and less deformation at rest, particularly for the RA. Despite a similar extent of remodelling, the pattern in women had greater bi-atrial myocardial deformation and smaller RA size.     

The effects of gender on the transition of transfer students into a new school

The present study describes a peer-tutoring program designed to utilize computerassisted instruction to help first through fourth graders who were entering a new school. Tutored girls increased their positive self-perceptions as a result of the tutoring program, whereas boys declined in positive self-perceptions, while exhibiting gains in reading scores. These findings suggest that prevention efforts need to consider the specific adaptation needs of transfer students by gender so as to insure a maximum fit between individual need and program scope.