La surimplication maternelle et l'anxiété chez l'enfant dans un contexte de stress prénatal maternel : une étude observationnelle de QF2011 Queensland Flood Study

Les troubles anxieux apparaissent très tôt chez les jeunes. Les études corrélationnelles suggèrent que plusieurs facteurs, tels que le stress prénatal maternel (SPM) et la surimplication maternelle contribueraient à leur développement et à leur maintien. L’objectif de l’étude est de mieux comprendre si la surimplication maternelle est une cause ou une conséquence de l’anxiété chez l’enfant, le tout dans un contexte de stress prénatal maternel causé par un désastre naturel. L’échantillon fait partie d’un projet plus grand dans lequel les stress objectif et subjectif ont été mesurés chez les femmes enceintes lors de l’inondation en 2011 à Queensland en Australie. L’échantillon de l’étude inclut 72 dyades mère-enfant, ayant complété une tâche difficile de casse-tête, d’une durée de 5 minutes, lorsque les enfants étaient âgés de 4 ans. À partir des vidéos, les observateurs ont évalué le comportement maternel (la surimplication) et le comportement de l’enfant (l’anxiété) en continu. Des techniques d’analyse séquentielle ont été utilisées pour déterminer la probabilité qu’un comportement maternel de surimplication se produise avant ou après un comportement anxieux et vice versa. Les corrélations obtenues entre le SPM (objectif et subjectif), le comportement anxieux de l’enfant et le comportement de surimplication maternelle n’ont pas été significatives. Le comportement de surimplication n’est pas un médiateur entre le SPM (objectif et subjectif) et le comportement anxieux de l’enfant. Toutefois, les chances qu’un comportement maternel de surimplication suive un comportement anxieux chez l’enfant étaient plus grandes que les chances qu’un comportement anxieux suive un comportement maternel de surimplication. Nos résultats suggèrent que le stress prénatal maternel n’est pas associé avec le comportement de surimplication maternelle, ni avec le comportement anxieux de l’enfant. La surimplication maternelle est plutôt une réaction au comportement anxieux de l’enfant. Il est essentiel, pour de futures recherches, de se rappeler que l’enfant est un participant actif dans la relation mère-enfant et qu’il est important d’étudier la bidirectionnalité de la relation pour mieux comprendre et pour mieux intervenir.Anxiety disorders start very early in young people and several factors, such as prenatal maternal stress (PNMS) and maternal overinvolvement are believed to contribute to their development and maintenance. The objective of this study is to better understand if the overinvolvement of the mother is a cause or a consequence of the child’s anxiety, all in a context of prenatal maternal stress due to a natural disaster. The sample is part of a larger project that assessed the objective hardship and the subjective distress in women who were pregnant during the 2011 Queensland flood in Australia. The current sample included 72 mother-child dyads, completing a 5-minute puzzle task when the children were 4 years old. Observers rated maternal (overinvolved) and child (anxious) behaviors from videos continuously. Sequential analysis techniques were used to determine the likelihood of a maternal overinvolved behavior occurring before or after a child anxious behavior and vice versa. The correlations between PNMS (objective and subjective) and the child's anxiety and maternal over-involvement were not significant. Maternal overinvolvement did not mediate the relationship between PNMS (objective and subjective) and anxiety in children. However, the odds of maternal overinvolvement following child anxiety, was stronger than the odds of child anxiety following maternal overinvolvement. Our results suggest that prenatal maternal stress is not associated with maternal overinvolvement nor with child anxiety. It also suggests that maternal overinvolvement is a reaction to the child’s anxious behavior rather than a cause of it. Future research needs to keep in mind that the child is an active participant in the mother-child relationship and that it is important to study the bidirectionality of the relationship to better understand it and intervene

Improved electrical response in GdMnO3 doped (K, Na)NbO3 piezoelectric speaker

[(K0.368Na0.432)Li0.5][Nb0.86Sb0.04Ta0.1]O3 doped with 0.5 mol% GdMnO3 piezoelectric speakers were obtained, with good frequency sensibility in the range 20 Hz – 20 kHz. The additive used distorts the crystalline structure to a mixture of orthorhombic and tetragonal phases at room temperature. Also the dopants used shift the high temperature phase transitions toward room temperature. Good piezoelectric properties were obtained for doped samples, with an optimum piezoelectric charge constant d33 of 127 for [(K0.368Na0.432)Li0.5][Nb0.86Sb0.04Ta0.1]O3 - 0.5 mol % GdMnO3, a planar coupling coefficient of 0.39 and a quality factor of 102

Non-ambient FTIR study of thermally treated seashells

A large quantity of waste seashells (millions of tons) is discarded annually after mollusc consumption, which becomes a problem for the environment worldwide as these shells are a habitat for microbes which could turn into a public health issue [1]. On the other hand, waste shell biomaterials need a small amount of energy for recycling and processing into useful products for various applications. Calcium carbonate is essential in biomineralization, where it is the primary constituent of mollusc shells, crustacean cuticles, corals etc. In its pure form, it occurs naturally, under normal temperature and pressure conditions, in three anhydrous crystalline forms, namely calcite, aragonite and vaterite [2]. At high pressures, two further forms, namely calcite II and calcite III, are formed. The most stable form of calcium carbonate at atmospheric pressure and room temperature is calcite. The presence of both calcite and aragonite is very frequent in biologically produced calcium carbonate minerals. Though aragonite is metastable in aqueous solution, it can nucleate [3]. Aragonite is found in the nacre of the shells of bivalve molluscs, which provide a protection for these animals [4]. From the study of the marine bivalve species Mercenaria mercenaria and Crassostrea gigas, Weiner et al. [5] have shown that amorphous calcium carbonate is a precursor phase of aragonite. The present study, which is part of our efforts to convert seashells into useful products like hydroxyapatite, investigates the temperature influence on the calcite and aragonite in a processed shell sample by using Fourier-transform infrared spectroscopy (FTIR)

Incubation-based hydroxyapatite synthesis method using shells as Ca2+ source

Hydroxyapatite, the well-known calcium phosphate, was obtained on the surface of shells fragments by partial conversion of the latter, which served both as template and also provided the calcium ions required for synthesis. Confirmation of hydroxyapatite formation was acquired by recording and analyzing X-ray diffraction patterns. The degree to which the phosphate ions were consumed during the incubation-based synthesis was determined using a phosphate minicolorimeter, and the results indicate that a nucleation process takes place in the first 4 hours

Metal content of seashells from black sea's Romanian coast

The main metals from various species of seashells, commonly found on the Black Sea’s Romanian coast, were determined by using microwave plasma atomic emission spectroscopy (MP-AES) and energy-dispersive X-ray spectroscopy (EDX). As expected, calcium was the main component, followed by magnesium, aluminum, iron and manganese

Novel (K,Na)NbO3 based piezoelectric ceramic

Novel (1-x)(K0,5Na0,5)NbO3 – xGdAlO3 piezoelectric ceramics were obtained using solid state method. The phase purity was confirmed by X-ray diffraction. The unit cell parameters were refined. The results show the presence of a phase transition from orthorhombic to tetragonal