The role of insulin receptor substrate 2 in hypothalamic and β cell function

Insulin receptor substrate 2 (Irs2) plays complex roles in energy homeostasis. We generated mice lacking Irs2 in β cells and a population of hypothalamic neurons (RIPCreIrs2KO), in all neurons (NesCreIrs2KO), and in proopiomelanocortin neurons (POMCCreIrs2KO) to determine the role of Irs2 in the CNS and β cell. RIPCreIrs2KO mice displayed impaired glucose tolerance and reduced β cell mass. Overt diabetes did not ensue, because β cells escaping Cre-mediated recombination progressively populated islets. RIPCreIrs2KO and NesCreIrs2KO mice displayed hyperphagia, obesity, and increased body length, which suggests altered melanocortin action. POMCCreIrs2KO mice did not display this phenotype. RIPCreIrs2KO and NesCreIrs2KO mice retained leptin sensitivity, which suggests that CNS Irs2 pathways are not required for leptin action. NesCreIrs2KO and POMCCreIrs2KO mice did not display reduced β cell mass, but NesCreIrs2KO mice displayed mild abnormalities of glucose homeostasis. RIPCre neurons did not express POMC or neuropeptide Y. Insulin and a melanocortin agonist depolarized RIPCre neurons, whereas leptin was ineffective. Insulin hyperpolarized and leptin depolarized POMC neurons. Our findings demonstrate a critical role for IRS2 in β cell and hypothalamic function and provide insights into the role of RIPCre neurons, a distinct hypothalamic neuronal population, in growth and energy homeostasis

Affection, virtue, pleasure, and profit: Developing an understanding of friendship closeness and intimacy in western and Asian societies

The development of friendship understanding has rarely been explored from a cross-cultural perspective. In this study, children and adolescents from Iceland, China, Russia, and the former East Germany were investigated in one longitudinal and three cross-sectional samples. Children from three different Chinese ecologies were interviewed to account for within-culture variation. Participants were interviewed about friendship closeness and intimacy at ages 7, 9, 12, and 15 years. Their statements were scored according to (a) structural-developmental stages and (b) content aspects of friendship reasoning. Results reveal that the development of friendship reasoning of participants from all societies could be captured by the cognitive-structural stages and content categories developed in western cultures. At the same time, distinct cultural differences emerged, especially between the Russian and Chinese participants, on the one hand, and the Icelandic and East German participants, on the other hand. The within-China analyses reveal little differences for the content aspects of friendship understanding between the three ecologies, but differences in the cognitive-structural aspects of friendship reasoning were found. © 2008 The International Society for the Study of Behavioural Development

The effects of conflict role and intensity on preschoolers’ expectations about peer conflict

Using a puppet procedure depicting hypothetical conflict involving the participant and a peer, 96 preschoolers’ (48 boys and 48 girls; M 1/4 5.14 years, SD 1/4 0.78 years) expectations about peer conflict were assessed as a function of their role in the conflict (i.e., initiator of or responder to initial provocation) and the intensity level of the conflict. Initiators of conflict expected less conflict escalation and subsequent problems with the same peer from the conflict than did responders, particularly following low-intensity conflict. Findings also indicated that, for low-intensity but not high-intensity conflict, girls expected the same peer to provoke them during a subsequent interaction more often than did boys. Results provide further support for assessing preschoolers’ understanding of conflict and are consistent with previous work demonstrating a self-serving bias in young children’s perceptions and reports of their conflicts with other children. Moreover, findings are discussed in terms of their implications for the development of peer relations.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Freezing influences diffusion of reducing sugars in carrot cortex

The loss of reducing sugars from raw and previously frozen carrot cortex tissue immersed in warm water was studied as a function of temperature (40–100°C). Leaching was described as a diffusional mechanism by application of Fick's 2nd law. This approach successfully modeled losses from raw carrots at temperatures higher than 60°C. At low temperatures diffusion was much slower, due to a high resistence of the tissues to mass transfer, and Fick's 2nd law could not be applied. Previously frozen carrots showed a Fickian behaviour through the range of temperatures and diffusivities were much higher. Dependence of diffusivity on temperature followed an Arrhenius type equation for the two cases. However, the activation energy of pre-frozen carrots was lower, indicating loss of sensitivity to temperature variations.info:eu-repo/semantics/acceptedVersio

Uma atividade "sexo" que faz relfletir

Neste artigo, descrevem-se características comportamentais de uma amostra de adolescentes internadas em instituições, apresentando brevemente o problema em questão para depois dar os conceitos que estão na base da reorganização das atividades a elas propostas. Na seqüência, explica-se como funciona a atividade "Sexo", cujos objetivos são o de informar as adolescentes, fazê-las falar sobre sua sexualidade, e refletir, levantando a questão da prolongação da intervenção da atividade de educação sexual, discutindo sobre o grupo de ajuda por ocasião dos abusos sexuais vividos na primavera de 1994