Scientific mental representations of Thermodynamics

The analysis of a certain number of textbooks on Thermodynamics is expounded with the aim of showing that several mental representations of this subject matter are present in scientific literature. This analysis points out divergent attitudes not only towards the definition of fundamental concepts principles, but also towards the epistemological status of Thermodynamics. These attitudes underlie-sometimes tacitly-the relationship between the macroscopic and the microscopic approach on one side and between the state or process approach on the other. We also show the importance of both the historical reconstruction and the epistemological analysis for a deeper understanding of what these different mental representations underlie and entail.     

Effectiveness of specific factors in community-based intervention for child-witnesses of interparental violence: A randomized trial

A community-based intervention with specific factors for children and parents exposed to interparental violence (IPV) was compared with a control intervention based on non-specific factors. We hypothesized that participation in an intervention with specific factors, focused on IPV, parenting and coping, would be associated with better recovery. IPV exposed children and parents were group randomized over a specific factors- and control intervention. Baseline, posttest and follow-up measurements of 155 parents and children (aged 6–12 years, 55.5% boys) were fitted in a multilevel model. Outcomes were parent and teacher reported children's internalizing and externalizing problems (CBCL, TRF), child self-reported depressive symptoms (CDI) and parent and child reported children's post-traumatic stress symptoms (TSCYC, TSCC). Based on intention-to-treat and completer analyses, children in the specific factors intervention did not show better recovery than children in the control intervention. Children in both interventions decreased significantly in parent-reported children's internalizing and externalizing problems and post-traumatic stress symptoms. Children reported a decrease in their mean level of depressive and post-traumatic stress symptoms. Teachers reported a decrease in internalizing problems, but not in externalizing problems. No association between time since exposure and level and course of symptoms was found. Treatment differentiation was assessed and both programs were significantly different on hypothesized effective factors. Higher treatment adherence in both programs did not result in a larger difference in recovery. IPV exposed children improve over the course and after participating in a community-based child- and parent program, but specific factors in intervention may not carry additional benefits when implemented in community settings.     

‘Slow Science’: Building scientific concepts in physics in high school

In this study, a progressive-learning approach to physics, based on knowledge-building pedagogy, was compared to a content-centered approach in which explanations, experiments, and discussions are centered on the transmission of knowledge. Forty-six students attending the first year of high school participated in this study over a whole school year. Students’ knowledge and mastery of physics concepts were assessed through questionnaires containing both open-ended and multiple-choice questions. Overall, the ‘progressive-learning' group outperformed the content-centered group. Results are discussed in relation to the theoretical background and the experimental teacher's diary of classroom activities. The main conclusion achieved by this study is that the teaching of physics should be slow, cyclic, and developmentally appropriate for the context.     

Effects of competition level on the centre forward role of men's water polo

Abstract

This study aimed to compare specific technical and tactical indicators of the team and centre forward role of Euro League, and Italian Serie A1, Serie A2, and Serie B men's water polo club competitions. A notational analysis was performed on 21 water polo matches to evaluate the occurrence of technical and tactical team and centre forward indicators, highlighting differences among championships according to chi-square analyses. Differences emerged for Counterattack (P < 0.001) and Power-Play (P < 0.001) possessions, Even (P < 0.001; Euro League: 3 ± 1, Serie A1: 3 ± 2, Serie A2: 3 ± 2, Serie B: 6 ± 4) and Power-Play (P = 0.001) goals, and exclusions and penalties (P = 0.008) of the team during Even possessions. Relatively to the role analyses, effects emerged for perimeter players playing events (P = 0.049), as well as for centre forwards' goals (P = 0.007) and exclusions and penalties (P < 0.001; Euro League: 8 ± 1, Serie A1: 6 ± 2, Serie A2: 6 ± 2, Serie B: 3 ± 2) occurring at the end of Even possessions. Therefore, in Euro League, and Italian Serie A1 and Serie A2, teams perform a high occurrence of Power-Play possessions following up an exclusion, especially achieved by the centre forward during Even possessions, while, in Italian Serie B, goals were mostly scored during Even possessions, with a relevant contribution from the centre forward role.     

Yo-Yo IR2 testing of elite and sub-elite soccer players: Performance,heart rate response and correlations to other interval tests

Abstract

We examined performance, heart rate response and construct validity of the Yo-Yo IR2 test by testing 111 elite and 92 sub-elite soccer players from Norway and Denmark. VO₂max, Yo-Yo IR1 and repeated sprint tests (RSA) (n = 51) and match-analyses (n = 39) were also performed. Yo-Yo IR2 and Yo-Yo IR1 performance was 41 and 25% better (P < 0.01) for elite than sub-elite players, respectively, and heart rate after 2 and 4 min of the Yo-Yo IR2 test was 20 and 15 bpm (9 and 6% HRmax), respectively, lower (P < 0.01) for elite players. RSA performance and VO₂max was not different between competitive levels (P > 0.05). For top-teams, Yo-Yo IR2 performance (28%) and sprinting distance (25%) during match were greater (P < 0.05) than for bottom-teams. For elite and sub-elite players, Yo-Yo IR2 performance was correlated (P < 0.05) with Yo-Yo IR1 performance (r = 0.74 and 0.76) and mean RSA time (r = ?0.74 and ?0.34). We conclude that the Yo-Yo IR2 test has a high discriminant and concurrent validity, as it discriminates between players of different within- and between-league competitive levels and is correlated to other frequently used intermittent elite soccer tests.     

Anthropometry and body composition of female handball players according to competitive level or the playing position

Abstract

Anthropometry and body composition were investigated in 43 female handball players from the Italian championships, grouped according to their competitive level (elite vs. sub-elite) or their playing position [goalkeeper (n = 7), back (n = 14), wing (n = 18), or pivot (n = 4)]. The anthropometry consisted of several circumferences, lengths, widths, and skinfold measurement at six sites; the regional and total body compositions were assessed by means of dual-energy X-ray absorptiometry (DXA). One-way ANOVA was used for statistical analysis, with a Bonferroni post-hoc test where needed. The results showed that elite players have significantly lower percentages of fat and higher bone mineral content than sub-elite as well as a clear tendency to accrue more lean mass, especially in upper limbs. Overall, the physical characteristics and body composition of handball players in Italy compared unfavourably with those in other countries, suggesting a need for improved selection and training. When playing position was included in the analysis of the whole group of handball players (n = 43) significant differences were found between the stature, mass, body mass index (BMI), several skinfolds, circumferences and lengths, and total body mineral mass, lean mass and fat mass of players in different positions. Post-hoc analysis suggests that players on the wing and in goalkeeper positions differed most from one another. These findings confirm and expand on previous data about the presence of anthropometric differences within playing positions in handball.     

The co-evolution of e-government and public libraries: Technologies,access, education,and partnerships

While many studies have discussed the impacts of electronic government (e-government) on public libraries, little research has considered the extent to which the current federal government's implementation of e-government relies on the public technology access, training, and support provided by public libraries. A range of data and policy materials are drawn upon in order to illuminate the co-evolution of public libraries and e-government. Beginning with a discussion of the development of e-government and its impacts in public libraries, the access, goals, and challenges of e-government are detailed as they relate to libraries, and the areas in which current implementations of e-government would not be possible without public libraries. Based on the explorations of the co-evolution of e-government and public libraries, key policy issues are offered that require reconceptualization in order to better support the interrelationship between e-government and public libraries.     

Yo-Yo IR2 testing of elite and sub-elite soccer players: Performance, heart rate response and correlations to other interval tests

Abstract We examined performance, heart rate response and construct validity of the Yo-Yo IR2 test by testing 111 elite and 92 sub-elite soccer players from Norway and Denmark. VO(2)max, Yo-Yo IR1 and repeated sprint tests (RSA) (n?=?51) and match-analyses (n?=?39) were also performed. Yo-Yo IR2 and Yo-Yo IR1 performance was 41 and 25% better (P??0.05). For top-teams, Yo-Yo IR2 performance (28%) and sprinting distance (25%) during match were greater (P?相似文献   

Broadband for public libraries: Importance,issues, and research needs

U.S. public libraries provide free public internet services to the communities that they serve, but require robust, high-speed broadband internet connections to continue meeting public demands. The 2008–2009 Public Library Funding & Technology Access Study (PLFTAS) illustrates challenges that public libraries encounter in achieving broadband connectivity and equipment upgrades, and maintaining acceptable levels of services as they meet continually increasing internet-enabled service demands. This article: 1) analyzes the ability of public libraries to serve as a community-based public internet access point in the context of limited funding and access to telecommunications services and equipment; 2) discusses key policy issues that affect the provision of public library internet-enabled services through broadband; 3) provides recommendations for policy makers to include libraries as part of a larger national-level telecommunications policy; and 4) identifies a number of topics and issues that need further investigation and research in this shifting policy environment.