Dielectric relaxations of nanocomposites composed of HEUR polymers and magnetite nanoparticles

We investigate the dynamics of nanocomposites composed of hydrophobically modified ethoxylated urethanes (HEUR) and magnetite nanoparticles (MNPs) as dry films. Weemployed dielectric relaxation spectroscopy (DRS) in combination with differential scanning calorimetry (DSC) and thermally stimulated depolarization currents (TSDC).The three techniques reveal a strong heterogeneity of the matrix of the nanocomposites, consisting of (i) a crystalline poly(ethyleneoxide) PEO bulk phase, (ii) an amorphous PEO portion, and (iii) small PEO crystallites which experience different constraints than the PEO bulk phase. TSDC and DRS reveal a very high direct current (DC)-conductivity of the pure matrix, which increases with MNPs concentration. The increase of the DCconductivity is not related to an increase of the segmental mobility, but most likely to the change of the morphology of the hydrophobic domains of the polymer matrix, due to the formation of large MNPs clusters. Indeed, the MNPs neither influence the segmental dynamics of the polymer nor the phase behavior of the polymer matrix. The addition of MNPs slightly increases the activation energy related to the γ-relaxation of the polymer. This effect might be related to the changes in nano-morphology as demonstrated by the slight increase of the degree of crystallinity. The analysis of the DRS data with the electrical modulus M’’(ω) and the derivative ε’’der formalism allow us to identify a low-frequency process in addition to the conductivity relaxation. This low-frequency dispersion is also revealed by TSDC. It is most likely related to the Maxwell-Wagner- Sillars relaxation, which typically occurs in systems which feature phase separation. The detailed investigation of the dielectric properties of these novel nanocomposites with increasing MNPs concentration will be useful for their practical application, for example as absorbers of electromagnetic waves

«La relation de limitation et d’exception dans le français d’aujourd’hui : excepté, sauf et hormis comme pivots d’une relation algébrique »

L’analyse des emplois prépositionnels et des emplois conjonctifs d’ “excepté”, de “sauf” et d’ “hormis” permet d’envisager les trois prépositions/conjonctions comme le pivot d’un binôme, comme la plaque tournante d’une structure bipolaire. Placées au milieu du binôme, ces prépositions sont forcées par leur sémantisme originaire dûment métaphorisé de jouer le rôle de marqueurs d’inconséquence systématique entre l’élément se trouvant à leur gauche et celui qui se trouve à leur droite. L’opposition qui surgit entre les deux éléments n’est donc pas une incompatibilité naturelle, intrinsèque, mais extrinsèque, induite. Dans la plupart des cas (emplois limitatifs), cette opposition prend la forme d’un rapport entre une « classe » et le « membre (soustrait) de la classe », ou bien entre un « tout » et une « partie » ; dans d’autres (emplois exceptifs), cette opposition se manifeste au contraire comme une attaque de front portée par un « tout » à un autre « tout ». De plus, l’inconséquence induite mise en place par la préposition/conjonction paraît, en principe, tout à fait insurmontable. Dans l’assertion « les écureuils vivent partout, sauf en Australie » (que l’on peut expliciter par « Les écureuils vivent partout, sauf [qu’ils ne vivent pas] en Australie »), la préposition semble en effet capable d’impliquer le prédicat principal avec signe inverti, et de bâtir sur une telle implication une sorte de sous énoncé qui, à la rigueur, est totalement inconséquent avec celui qui le précède (si « les écureuils ne vivent pas en Australie », le fait qu’ils « vivent partout » est faux). Néanmoins, l’analyse montre qu’alors que certaines de ces oppositions peuvent enfin être dépassées, d’autres ne le peuvent pas. C’est, respectivement, le cas des relations limitatives et des relations exceptives. La relation limitative, impliquant le rapport « tout » - « partie », permet de résoudre le conflit dans les termes d’une somme algébrique entre deux sous énoncés pourvus de différent poids informatif et de signe contraire. Les valeurs numériques des termes de la somme étant déséquilibrées, le résultat est toujours autre que zéro. La relation exceptive, au contraire, qui n’implique pas le rapport « tout » - « partie », n’est pas capable de résoudre le conflit entre deux sous énoncés pourvus du même poids informatif et en même temps de signe contraire : les valeurs numériques des termes de la somme étant symétriques et égales, le résultat sera toujours équivalent à zéro

Qualitative aspects of teaching and manipulative skill enhancement: Is there any relationship?

The purpose of this study was to investigate the relationship between certain qualitative aspects of teaching and students' achievement in fundamental manipulative skills. Six elementary physical education teachers were required to teach to their students an eight-lesson unit in throwing and catching, as part of their normal curriculum. Students were pre- and post-tested on the above manipulative skills using the Test of Gross Motor Development (Ulrich, 1985) for the qualitative performance and the Michigan Educational Assessment Program (MEAP, 1984) for the quantitative performance. All lessons were video- and audio-taped, and coded using the Qualitative Measures of Teaching Performance Scale (QMPTS: Rink and Werner, 1989) to evaluate teaching performance. Results showed that the total QMTPS score was significantly correlated with a) quantitative performance on catching, and b) qualitative performance on throwing. A correlation (although not significant) was also found between the total QMTPS score and a) student overall performance, b) student overall quantitative performance. It seems that certain qualitative aspects of teaching contribute to fundamental manipulative skill enhancement

Women and Peace Negotiations in Cyprus

The integration of a gender agenda in the peace negotiations in Cyprus has been elusive over the five decades. However, it is only since the late 2000s that civil society and international observers have problematized this lack and attempted to address it through various initiatives. These have included local and international efforts to mobilize Cypriot women across the divide around an agenda based on UN Security Council Resolution 1325 (2000) on Women, Peace and Security, which led to the formation of the Gender Advisory Team in 2009. They have also included research efforts by local and international organizations and think tanks to document the extent to women’s inclusion in the peace process on the island. These efforts eventually led to the setup of the Technical Committee on Gender Equality which is attached to the peace negotiations since 2015, but the impact of which has remained marginal. One of the key problems frustrating the integration of a gender agenda in the peace negotiations remains the fact that despite great advances in both societies north and south of the dividing line in many areas of gender equality, the hard politics relating to the Cyprus conflict and its resolution remain contentious and politically perilous to oppose while also being discursively disconnected from perceptions of “gender” and feminist concerns

Qualitative aspects of teaching and manipulative skill enhancement : is there any relationship ?

Utilisation d'un outil de mesure de la qualité des interventions de l'enseignant d'éducation physique (Qualitative measures of teaching performance scale de Rink et Werner, 1989) pour évaluer les effets sur les apprentissages du lancer et de la réception de balle chez des enfants de 6-7 ans

Biomarkers of exposure in environment-wide association studies – Opportunities to decode the exposome using human biomonitoring data

Background: The European Union's 7th Framework Programme (EU's FP7) project HEALS – Health and Environment-wide Associations based on Large Population Surveys – aims a refinement of the methodology to elucidate the human exposome. Human biomonitoring (HBM) provides a valuable tool for understanding the magnitude of human exposure from all pathways and sources. However, availability of specific biomarkers of exposure (BoE) is limited. Objectives: The objective was to summarize the availability of BoEs for a broad range of environmental stressors and exposure determinants and corresponding reference and exposure limit values and biomonitoring equivalents useful for unraveling the exposome using the framework of environment-wide association studies (EWAS). Methods: In a face-to-face group discussion, scope, content, and structure of the HEALS deliverable “Guidelines for appropriate BoE selection for EWAS studies” were determined. An expert-driven, distributed, narrative review process involving around 30 individuals of the HEALS consortium made it possible to include extensive information targeted towards the specific characteristics of various environmental stressors and exposure determinants. From the resulting 265 page report, targeted information about BoE, corresponding reference values (e.g., 95th percentile or measures of central tendency), exposure limit values (e.g., the German HBM I and II values) and biomonitoring equivalents (BEs) were summarized and updated. Results: 64 individual biological, chemical, physical, psychological and social environmental stressors or exposure determinants were included to fulfil the requirements of EWAS. The list of available BoEs is extensive with a number of 135; however, 12 of the stressors and exposure determinants considered do not leave any measurable specific substance in accessible body specimens. Opportunities to estimate the internal exposure stressors not (yet) detectable in human specimens were discussed. Conclusions: Data about internal exposures are useful to decode the exposome. The paper provides extensive information for EWAS. Information included serves as a guideline – snapshot in time without any claim to comprehensiveness – to interpret HBM data and offers opportunities to collect information about the internal exposure of stressors if no specific BoE is available