Colorimetric Evaluation of Pictorial Coatings in Conservation of Plasterworks from the Islamic Tradition

ABSTRACT

The main aim of our current investigation is the colorimetric evaluation of protective treatments (consolidants) applied to traditional Islamic plasterworks, under natural ageing conditions. From analyses of the original pictorial plaster remains in the Courtyard of the Maidens of the Real Alcázar in Seville, Spain (a World Heritage Site) we prepared test specimens, using materials and techniques similar to the original ones. We analysed 56 test specimens painted with four pigments (yellow, green, blue, and red), using two different binders (animal glue and gum arabic), onto which five representative consolidants were applied: barium hydroxide, acrylic copolymer, polyvinyl butyral, ethyl silicate, and bacterial carbonatogenesis. The test specimens were subjected to natural ageing for one year (indoors and outdoors), enabling a colorimetric assessment to be made of the changes of the polychrome surfaces. The colorimetric heterogeneity of the 56 specimens after ageing registered an average value of 2.7 CIELAB units, assessed using the mean colour difference with respect to the mean. In the aged specimens, the addition of consolidants resulted in average colour differences (mainly lightness differences) of 10.7 and 6.7 CIELAB units, considering as a reference the specimens without consolidants aged indoors and outdoors, respectively. These colour differences were very similar for both binders but not for the four pigments, higher values being found for the blue and red pigments. Considering as reference the samples without consolidants aged outdoors, we found no statistically significant colour differences, either among the five consolidants (p?=?.094) nor the two binders (p?=?.674) used. In addition to the magnitude of colour differences, the choice of the most appropriate consolidants must also consider aspects related to performance and effectiveness. Overall, for the type of paints tested, the polyvinyl butyral consolidant appeared to perform the best, followed by the ethyl silicate.     

Acute effects of small changes in crank length on gross efficiency and pedalling technique during submaximal cycling

ABSTRACT

The main purpose of this study was to assess the acute effects of small changes in crank length (assumable by competitive cyclists) on metabolic cost and pedalling technique during submaximal cycling. Twelve amateur road cyclists performed three sets of submaximal pedalling (150, 200 and 250 W) at a constant cadence (91.3 ± 0.8 rpm) in a randomised order with three commonly used crank lengths, preferred (172.5–175 mm), +5 mm and ?5 mm. Energy cost of pedalling, kinetic and kinematic variables were simultaneously registered. Changes in crank length had no significant effect on heart rate (144 ± 13, 145 ± 12 and 145 ± 13 bpm, respectively) and gross efficiency (GE) (20.4 ± 2.1, 20.1 ± 2.2 and 20.3 ± 2.4%, respectively). A longer crank induced a significant (P < 0.05) reduction of positive impulse proportion (PIP) (0.9–1.9%) due to a greater maximum (1.0–2.3 N · m) and minimum torque (1.0–2.2 N · m). At the same time, the maximum flexion and range of motion of the hip and knee joints were significantly increased (1.8–3.4° and P < 0.05), whereas the ankle joint was not affected. In conclusion, the biomechanical changes due to a longer crank did not alter the metabolic cost of pedalling, although they could have long-term adverse effects. Therefore, in case of doubt between two lengths, the shorter one might be recommended.     

Effects of dynamic resistance training on fascicle length and isometric strength

The aims of this study were to assess changes in muscle architecture, isometric and dynamic strength of the leg extensor muscles, resulting from dynamic resistance training, and the relationships between strength and muscle architecture variables. The participants (n = 30) were randomly assigned to one of two groups. The training group (n = 16; age 21.8 +/- 2.3 years, body mass 74.8 +/- 9.2 kg, height 1.75 +/- 0.08 m) performed dynamic resistance training for 13 weeks. The control group (n = 14; age 19.9 +/- 1.5 years, body mass 74.0 +/- 8.5 kg, height 1.76 +/- 0.05 m) did not perform any resistance training. Maximal dynamic and isometric strength were tested in both groups, before and after the training period. The members of the training group used the free-weight squat lift (90 degrees ) as their training exercise. The concentric phase of the squat was performed explosively. Skeletal muscle architecture of the vastus lateralis was visualized using ultrasonography. At the end of the study, significant increases in vastus lateralis muscle thickness (+6.9%, P < 0.001), fascicle length (+10.3%, P < 0.05), one-repetition maximum (+8.2%, P < 0.05), rate of force development (+23.8%, P < 0.05) and average force produced in the first 500 ms (+11.7%, P < 0.05) were seen only in the training group. Adaptations to the muscle architecture in the training group limited the loss of fibre force, and improved the capacity for developing higher velocities of contraction. The architectural changes in the training group were similar to those seen in studies where high-speed training was performed. In conclusion, dynamic resistance training with light loads leads to increases in muscle thickness and fascicle length, which might be related to a more efficient transmission of fibre force to the tendon.     

Football and justice devices: hybrid ethical narratives,sanctions and legitimacy of interests

The concept of justice has gradually colonized sports’ narratives in general and professional football ones in particular. Discourses on justice often give rise to ambiguous, unclear narrations with a great deal of noise and opportunism. The aim of this article is to apply the concept of justice devices to clarify the range of measures used and link these to the diverse agents that attempt to gain legitimacy and power through them. In an initial characterisation, we highlight conventional and post-conventional models of ethics of justice. Subsequently, we compare these models to the systems of justice employed by football’s governing institutions, FIFA and UEFA. Finally, we analyse a paradigmatic event of judicial interpretation by various actors using the case of ‘Luiz Adriano’. In this article, we reveal some of the specific uses, settings and strategic aims of justice devices employed by the main actors involved in international football.     

Velocity- and power-load relationships in the half,parallel and full back squat

This study aimed to compare the load-velocity and load-power relationships of three common variations of the squat exercise. 52 strength-trained males performed a progressive loading test up to the one-repetition maximum (1RM) in the full (F-SQ), parallel (P-SQ) and half (H-SQ) squat, conducted in random order on separate days. Bar velocity and vertical force were measured by means of a linear velocity transducer time-synchronized with a force platform. The relative load that maximized power output (Pmax) was analyzed using three outcome measures: mean concentric (MP), mean propulsive (MPP) and peak power (PP), while also including or excluding body mass in force calculations. 1RM was significantly different between exercises. Load-velocity and load-power relationships were significantly different between the F-SQ, P-SQ and H-SQ variations. Close relationships (R² = 0.92–0.96) between load (%1RM) and bar velocity were found and they were specific for each squat variation, with faster velocities the greater the squat depth. Unlike the F-SQ and P-SQ, no sticking region was observed for the H-SQ when lifting high loads. The Pmax corresponded to a broad load range and was greatly influenced by how force output is calculated (including or excluding body mass) as well as the exact outcome variable used (MP, MPP, PP).     

Transversal traits in science education research relevant for teaching and research: A meta‐interpretative study

This study is a meta‐interpretative analysis that focuses on research conducted and published by other researchers. Concepts central to this study include global practical relevance, curriculum design, and formative situation. We analyzed 35 studies selected from 374 published studies in the years 2000 and 2001 in three journals referenced in the International Scientific Index. Using a replicable methodology developed specifically for this research, we found evidence of s clusters of variables that suggest the existence of transversal traits in the 35 science education research studies. These results form a reference framework of theoretical and practical knowledge relevant for research and practice pertaining to teaching and learning science. © 2008 Wiley Periodicals, Inc. J Res Sci Teach 45: 574–599, 2008     

Grading in Portuguese secondary school physical education: assessment parameters,gender differences and associations with academic achievement

ABSTRACT

Background: Assessment is crucial for the quality of teaching and learning in physical education (PE). Currently little is known about the students’ level of achievement in PE and about the parameters used for calculating the PE grades. Although there is evidence that boys are more active outside school than girls and participate more in organized sports, few studies have examined possible differences between genders in PE achievement. Furthermore, despite the current interest in the relationship between motor competencies and cognitive functioning, limited research has examined if PE grades are associated with academic achievement.

Purpose: Considering the lack of information on the current level of students’ success in PE, the main aim of this study is to examine the PE grades of Portuguese students in secondary school. Specifically, this study analysis the level of students’ achievement in PE, the relation of PE grades with other school subjects’ grades, compares the PE grades between boys and girls, and presents the PE summative assessment parameters used in schools.

Method: Participants were 1936 students (57% girls) from the 10th, 11th and 12th grades (16.8?±?1.3 years old) attending eleven Portuguese secondary schools. Information was gathered on their grades in PE and in the other school subjects at the end of the school year. Information on the specific assessment parameters used in each school was also collected.

Results: The average grades in PE were 14.9?±?2.3 points (20-point scale). Only ～1% of students with a final PE grade had a negative performance (<10 points). PE grades were relatively higher than in most of the other school-subjects and for most students (68.7%) the PE classification raised their overall average grade. The level of correlation between grades in PE and in other school subjects was statistically significant (r's?=?.13 to .29, p?<?.05) although lower than that between grades in the other school subjects (r's?=?.44 to .84, p?<?.01). There were significant differences between girls’ and boys’ grades in PE (14.3?±?2.3 and 15.9?±?2.1 points, respectively). The school assessment parameters prioritize physical performance over participation and attitude.

Conclusion: The Portuguese students’ level of achievement in PE seems to be very satisfactory. However, as boys have higher grades than girls it is urgent to find appropriate strategies to tackle this problem. The associations found between PE grades and academic achievement could have relevant repercussions considering the current debate about the status of PE and about the relationship between motor and cognitive competencies. It is also relevant that the schools’ summative assessment parameters are based mainly on skill mastery and not on effort and participation. This study provided a brief glance into some aspects of the assessment of PE in Portugal and is it is desirable that future investigations examine the teacher's assessment practices.     

Relationships between intrinsic motivation, physical self-concept and satisfaction with life: a longitudinal study

In this study, we examined the relationships between intrinsic motivation, physical self-concept, and satisfaction with life using cross-lagged panel models analysed via structural equation models. The sample consisted of 293 participants (148 men, 145 women) aged 18-70 years who performed diverse types of physical exercise. Three alternative models were tested. The data were better represented by a model in which physical self-concept mediates the relationships between intrinsic motivation and satisfaction with life. Specifically, the direct effects of intrinsic motivation on physical self-concept, and of physical self-concept on satisfaction with life were significant, with the amount of explained variance increasing over time. In conclusion, people who perform physical exercise regularly, and who have fun over time will tend to have a better physical self-perception and, consequently, more psychological well-being.     

Contribution of historical Spanish inventions to the knowledge of olive oil industrial heritage

This article presents new research, which has the objective of quantifying the knowledge produced by historical technological innovations in the field of olive oil industrial heritage. It studies inventions related to the mechanical processes of the extraction of olive oil between 1826 and 1966, which are recorded in the Historical Archive of the Spanish Patent and Trademark Office. It uses a new adaptation of the methodology of knowledge management (KM) defined by Nonaka and Takeuchi. We have obtained the knowledge value of each innovation according to the level of technological knowledge registered at the time, while distinguishing between the historical evolution of inventions relating to milling and those relating to pressing. In the first analysis, the results show a recession in the quantitative level of knowledge in the olive oil sector with respect to the technological potential of the time. However, when contrasted with the events relating to industrial heritage at the time, it is possible to account for this technological evolution and prove the validity of the methodology used. The results show that general evolution of the knowledge generated has decreased, particularly in the pressing process, although this is not the case in the milling process.