A single nucleotide mutation in the dual-oxidase 2 (DUOX2) gene causes some of the panda's unique metabolic phenotypes

The giant panda (Ailuropoda melanoleuca) is an iconic bear native to China, famous for eating almost exclusively bamboo. This unusual dietary behavior for a carnivore is enabled by several key adaptations including low physical activity, reduced organ sizes and hypothyroidism leading to lowered energy expenditure. These adaptive phenotypes have been hypothesized to arise from a panda-unique single-nucleotide mutation in the dual-oxidase 2 (DUOX2) gene, involved in thyroid hormone synthesis. To test this hypothesis, we created genome-edited mice carrying the same point mutation as the panda and investigated its effect on metabolic phenotype. Homozygous mice were 27% smaller than heterozygous and wild-type ones, had 13% lower body mass-adjusted food intake, 55% decreased physical activity, lower mass of kidneys (11%) and brain (5%), lower serum thyroxine (T4: 36%), decreased absolute (12%) and mass-adjusted (5%) daily energy expenditure, and altered gut microbiota. Supplementation with T4 reversed the effects of the mutation. This work uses a state-of-the-art genome editing approach to demonstrate the link between a single-nucleotide mutation in a key endocrine-related gene and profound adaptive changes in the metabolic phenotype, with great importance in ecology and evolution.     

La Copie de Texte comme Indicateur de l’Apprentissage de la Langue Ecrite par l’Enfant

The behavior of 34 first-grade children was observed when copying a text — their procedures for dividing the text verbal behavior and written production — in order to obtain task with which to follow the child’s progress through the first two years of schooling. Four successive levels appear after analysis of these data. On the first level, the construction of written units, the child faces particular problems with the title, lines, blanks and letters. The text is merely a commonplace object for the child. The second, or literal, level involves systematic letter-by-letter copying; letter naming appears. The text becomes a sequence of letters. On the third level, the child strives to copy visually and/or phonetically identifiable groups of letters: phonemes, syllables, or pronounceable non-syllabic strings of letters. Oral support is often implicit. The text is not seen by the child as a representation of speech. The word constitutes the unit of reference on the fourth level. The wide span group succeeds in copying the text word-by-word, while the narrow-span subgroup needs to repeat the trial twice, using the syllable as the support unit. Oral behavior is omnipresent. The text has become a sequence of words for the child.     

Le développement de l'éducation en Chine avant et pendant les années quatre-vingts

Sans résumé     

Media Naturalness and Online Learning: Findings Supporting Both the Significant- and No-Significant-Difference Perspectives

Is the use of an online course delivery format, when compared with the more traditional face‐to‐face format, good or bad in the context of university education? Those who subscribe to the no‐significant‐difference perspective argue that online delivery is good, because it allows students with time and geographic distance constraints to obtain the education that they need, with no significant negative impact on the quality of the learning experience. Others argue that online delivery is bad, advocating a version of the competing significant‐difference perspective, because the electronic communication media used for online delivery are not rich or natural enough to enable effective learning. This study contrasted students perceptions and grades in two different sections of the same course: one delivered entirely online and the other delivered face to face. Data were collected and analyzed at two points in time, namely, at the middle and end of a long semester. The study found support for both the no‐significant‐ and significant‐difference perspectives. At the middle of the semester, students in the online condition perceived communication ambiguity as significantly higher, and also obtained significantly lower grades, than students in the face‐to‐face condition. At the end of the semester, no significant differences were found.     

Contributions of stimulus-incentive and stimulus-response-incentive contingencies to response acquisition and maintenance

The effects of stimulus-incentive (S:IS) contingency, stimulus-response-incentive (S:R:IS) contingency, and stimulus-no-response-incentive (S:R:IS) contingency on the acquisition and maintenance of an instrumental approach-contact response in the rat were studied. The experiment, concerned mainly with the temporal distribution of responses, showed that (1) the S:IS contingency and the S:R:IS contingency produced the same temporal distribution of responses; (2) the S:R:IS contingency produced higher rates of response than the S:IS contingency; (3) the negative S:R:IS contingency did not completely eradicate already established responses; and (4)post-CS responding occurred on reinforced trials. Consideration of these results indicates that the critical factor determining the higher rates of response under the S:R:IS contingency may be the S:R:IS occasions experienced only in the instrumental procedure.     

Etude de la validité d’une classification a priori des compétences des elèves requises par les apprentissages scolaires

The publication by the French Ministry of Education of the findings of a survey designed to assess achievement of students at the end of elementary school (age 11) was the opportunity for educational specialists to construct a classification of the skills required for each of the exercises administered to the children in French, Mathematics, and the other objects. This classification reflected the aims stated in the Official Instructions on Education as regards knowledge and know-how for this age group. The present study was designed to test the validity of this classification, through an analisis of the consistency of success on exercises within a given subject and across subjects. The results show that although the classification is relatively pertinent for exercises within a given subject, this is not the case on an interdisciplinary level. The resulting structure shows the presence of a general factor, and content factors linked to each area of study. The discussion is centered on the feasability of a formative evaluation test based on an analytical diagnosis of skills in the young child.