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.     

Listening to Mothers II: Report of the Second National U.S. Survey of Women's Childbearing Experiences: Conducted January-February 2006 for Childbirth Connection by Harris Interactive(R) in partnership with Lamaze International

With permission from Childbirth Connection, the concise version of the Listening to Mothers II "Survey Methodology" is reprinted here. Harris Interactive(R) conducted Listening to Mothers II: Report of the Second National U.S. Survey of Women's Childbearing Experiences on behalf of Childbirth Connection. The survey consisted of 1,373 online interviews and 200 telephone interviews with women who had given birth in U.S. hospitals in 2005, with weighting of data to reflect the target population. Interviews were conducted from January 20 through February 21, 2006. The methods used to conduct the survey and analyze the data collected are described.     

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...     

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.     

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.     

Learning relations of knowledge transfer (KT) and knowledge integration (KI) of doctoral students during online interdisciplinary training: an exploratory study

ABSTRACT

Interdisciplinary training for doctoral students is an emerging scenario in higher education. The learning relations of knowledge transfer (KT: transferring knowledge from one person to another) and knowledge integration (KI: integrating or synthesizing perspectives from different disciplines) built by doctoral students play an important role in the process of interdisciplinary training. This study explores how doctoral students from a wide range of disciplines build learning relations of KT and KI during online interdisciplinary training. A mixed-methods approach was applied. First, longitudinal social network analysis (SNA) was employed to investigate the patterns of KT and KI relations over a seven-month training period. Subsequently, interviews were conducted to triangulate the SNA findings. SNA results show that the establishment of KI relations is significantly less than that of KT. Qualitative results show three themes explaining the challenges of KI relations, including challenges of online settings, the design of the training modules, and student involvement. Practical implications are drawn for the improvement of online interdisciplinary training, such as suggestions to promote KI and strategies for group learning.     

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.     

Helsen, Gilis, and Weston (2006) do not err in questioning the optical error hypothesis as the only major account for explaining offside decision-making errors

Oudejans, Bakker, and Beek (2007) recognize several relevant aspects of offside judgements in association football in the paper by Helsen, Gilis, and Weston (2006). We agree that the existing knowledge base on offside assessment needs to be expanded for two reasons. First, from a theoretical point of view it is important to examine how assistant referees can learn to deal with the limitations of the human visual information processing system. Second, from a practical point of view it is relevant to understand better refereeing performances and to identify potential explanations for incorrect offside decisions that could impact on the final outcome of the game. Oudejans et al. (2007) believe we both misinterpreted the optical error hypothesis and that our data set was unsuited to test it. Below, we react to these comments.