Defining and Operationalizing Appropriation for Science Learning

The goal of this article is to contribute to understanding the interplay between students' disciplinary engagement and their identity construction. The term appropriation, borrowed from scholars in linguistics and education, was chosen to capture this broader sense of productive learning that sits at the nexus of disciplinary engagement and identity. Appropriation implies deep conceptual understanding, but it also involves a reflexive process of transforming scientific discourse in a way that is authentic and personal. The core aim of this article is to turn the term appropriation into a theoretical construct by means of an analytic process of defining, operationalizing, and testing the definition against student interview and classroom data. Five discourse markers for operationalizing appropriation were discovered through this process. Appropriation, in our study, implies students’ discourse is (A) an expression of a personal “signature“ idea, (B) grounded in the discipline, (C) thick, in that it involves a metacognitive and epistemological dimension, (D) non-incidental, in the sense of being consistently used throughout classroom activities, and (E) a carrier of social relationships, in that it positions the student within classroom. The study is grounded in an extended intervention on thermodynamics in an Italian secondary school class (grade 12).     

Mechanical power,thrust power and propelling efficiency: relationships with elite sprint swimming performance

The purpose of this study was to explore the relationships between mechanical power, thrust power, propelling efficiency and sprint performance in elite swimmers. Mechanical power was measured in 12 elite sprint male swimmers: (1) in the laboratory, by using a whole-body swimming ergometer (W'_TOT) and (2) in the pool, by measuring full tethered swimming force (F_T) and maximal swimming velocity (V_max): W'_T = F_T · V_max. Propelling efficiency (η_P) was estimated based on the “paddle wheel model” at V_max. V_max was 2.17 ± 0.06 m · s^?1, η_P was 0.39 ± 0.02, W'_T was 374 ± 62 W and W'_TOT was 941 ± 92 W. V_max was better related to W'_T (useful power output: R = 0.943, P < 0.001) than to W'_TOT (total power output: R = 0.744, P < 0.01) and this confirms the use of the full tethered test as a valid test to assess power propulsion in sprinters and to estimate swimming performance. The ratio W'_T/W'_TOT (0.40 ± 0.04) represents the fraction of total mechanical power that can be utilised in water (e.g., η_P) and was indeed the same as that estimated based on the “paddle wheel model”; this supports the use of this model to estimate η_P in swimming.     

Integrity in UNESCO World Heritage Sites. A comparative study for rural landscapes

Since 2005, Outstanding Universal Value (OUV) is the standard by which United Nations Educational Scientific and Cultural Organization (UNESCO) evaluates world cultural heritage site suitability. The sites worthy of UNESCO preservation as well as the parameters used to demonstrate OUV are diverse. Our study focused on the uniquely distinguished rural landscape sites and the OUV parameter of integrity. Integrity however, is an elusive concept for which UNESCO provides no definitional protocol, and for which the scientific community objects to a static or pure historical interpretation. Given this, our work aims to analyse the concept of integrity and how it can be used to preserve the heritage of rural landscapes. After reviewing the UNESCO approach, we focused on the international scientific debate on the meaning and application of integrity. We designed and conducted a comparative study of UNESCO rural landscapes selected from the 2011 World Heritage List. Documents describing the historical, rural, and agro-ecological features of each of the fourteen rural sites were analysed. From this, several historical and ecological parameters were chosen as “values to have” and several socio-economic and management parameters were chosen as “values to maintain” to assess the integrity of each landscape. Our results found integrity to be a value of both cultural and natural landscapes and that it is key to site identity. We demonstrated that UNESCO assigns a high value to the following parameters: historical features, traditional crops and local products, land-use and agricultural practice permanence, and the presence of architecture related to agricultural activity. Finally, we found the relationship between culture and nature to characterize best the integrity of a rural landscape, rather than nature or culture alone.     

Evaluation of sample hemolysis in blood collected by S-Monovette? using vacuum or aspiration mode

Background:

In vitro hemolysis can be induced by several biological and technical sources, and may be worsened by forced aspiration of blood in vacuum tubes. This study was aimed to compare the probability of hemolysis by drawing blood with a commercial evacuated blood collection tube, and S-Monovette used either in the “vacuum” or “aspiration” mode.

Materials and methods:

The study population consisted in 20 healthy volunteers. A sample was drawn into 4.0 mL BD Vacutainer serum tube from a vein of one upper arm. Two other samples were drawn with a second venipuncture from a vein of the opposite arm, into 4.0 mL S-Monovette serum tubes, by both vacuum an aspiration modes. After separation, serum potassium, lactate dehydrogenase (LD) and hemolysis index (HI) were tested on Beckman Coulter DxC.

Results:

In no case the HI exceed the limit of significant hemolysis. As compared with BD Vacutainer, no significant differences were observed for potassium and LD using S-Monovette with vacuum method. Significant increased values of both parameters were however found in serum collected into BD Vacutainer and S-Monovette by vacuum mode, compared to serum drawn by S-Monovette in aspiration mode. The mean potassium bias was 2.2% versus BD Vacutainer and 2.4% versus S-Monovette in vacuum mode, that of LD was 2.7% versus BD Vacutainer and 2.1% versus S-Monovette in vacuum mode. None of these variations exceeded the allowable total error.

Conclusions:

Although no significant macro-hemolysis was observed with any collection system, the less chance of producing micro-hemolysis by S-Monovette in aspiration mode suggest that this device may be used when a difficult venipuncture combined with the vacuum may increase the probability of spurious hemolysis.     

Mechanical properties of the triceps surae: Differences between football and non-football players

Abstract

We investigated the mechanical properties of the triceps surae between professional, junior, and non-football players. Fifty-nine men participated in this study. The mechanical properties of the right legs’ triceps surae were measured in vivo using a free oscillation technique; no significant differences existed between the groups. The mean results for musculo-articular stiffness, damping coefficient, and damping ratio were as follows: professional football players (21523 N· m^?1, 330.8 N · s · m^?1, and 0.201); junior football players (21063 N · m^?1, 274.4 N · s · m^?1, and 0.173); and non-players (19457 N · m^?1, 281.5 N · s · m^?1, and 0.184). When analysed according to position, the results were as follows: defender (21447 N · m^?1, 308.6 N · s · m^?1, and 0.189); midfielder (20762 N · m^?1, 250.7 N · s · m^?1, and 0.157); winger (21322 N · m^?1, 335.1 N · s · m^?1, and 0.212); forward (22085 N · m^?1, 416.2 N · s · m^?1, and 0.254); and non-players (19457 N · m^?1, 281.5 N · s · m^?1, and 0.184).

Thus, football training, football games, and the position played had no effect on triceps surae mechanical properties. These results may be attributed to opposing adaptations between different types of training that are usually implemented in football. Alternatively, the minimum strain amplitude and/or frequency threshold of the triceps surae required to trigger adaptations of mechanical properties might not be achieved by football players with football training and matches.     

Stretching of DNA confined in nanochannels with charged walls

There is currently a growing interest in control of stretching of DNA inside nanoconfined regions due to the possibility to analyze and manipulate single biomolecules for applications such as DNA mapping and barcoding, which are based on stretching the DNA in a linear fashion. In the present work, we couple Finite Element Methods and Monte Carlo simulations in order to study the conformation of DNA molecules confined in nanofluidic channels with neutral and charged walls. We find that the electrostatic forces become more and more important when lowering the ionic strength of the solution. The influence of the nanochannel cross section geometry is also studied by evaluating the DNA elongation in square, rectangular, and triangular channels. We demonstrate that coupling electrostatically interacting walls with a triangular geometry is an efficient way to stretch DNA molecules at the scale of hundreds of nanometers. The paper reports experimental observations of λ-DNA molecules in poly(dimethylsiloxane) nanochannels filled with solutions of different ionic strength. The results are in good agreement with the theoretical predictions, confirming the crucial role of the electrostatic repulsion of the constraining walls on the molecule stretching.     

Improving comprehension online: effects of deep vocabulary instruction with bilingual and monolingual fifth graders

This quasi-experimental study investigated the effects of an Internet-delivered universally designed depth of vocabulary intervention that targeted both English-speaking and Spanish–English-speaking students. Two hundred forty students, 49% of whom were Spanish–English bilinguals, participated in the 16-week intervention. Intervention students read eight multimedia texts with embedded instruction on 40 words and reading strategy support. Students could access all texts and activities in Spanish and English. In comparison to a control group, there were significant intervention effects on a standardized measure of vocabulary knowledge, but effects were non-significant for comprehension. Similarly, significant effects on researcher-developed measures of vocabulary depth were detected, but not for a researcher-developed measure of breadth.