233 research outputs found

    Raman scattering study of electron-doped Prx_xCa1x_{1-x}Fe2_2As2_2 superconductors

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    Temperature-dependent polarized Raman spectra of electron-doped superconducting Prx_xCa1x_{1-x}Fe2_2As2_2 (x0.12x \approx 0.12) single crystals are reported. All four allowed by symmetry even-parity phonons are identified. Phonon mode of B1g_{1g} symmetry at 222 cm1^{-1}, which is associated with the c-axis motion of Fe ions, is found to exhibit an anomalous frequency hardening at low temperatures, that signals non-vanishing electron-phonon coupling in the superconducting state and implies that the superconducting gap magnitude 2Δc<272\Delta_c < 27meV.Comment: 4 pages, 3 figure

    Superconductivity at 22 K in Co-doped BaFe2As2 Crystals

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    Here we report bulk superconductivity in BaFe1.8Co0.2As2 single crystals below Tc = 22 K, as demonstrated by resistivity, magnetic susceptibility, and specific heat data. Hall data indicate that the dominant carriers are electrons, as expected from simple chemical reasoning. This is the first example of superconductivity induced by electron doping in this family of materials. In contrast to the cuprates, the BaFe2As2 system appears to tolerate considerable disorder in the FeAs planes. First principles calculations for BaFe1.8Co0.2As2 indicate the inter-band scattering due to Co is weak.Comment: 9 pages, 3 figure

    Raman scattering study of (Kx_xSr1x_{1-x})Fe2_2As2_2 (xx = 0.0, 0.4)

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    Polarized Raman spectra of non-superconducting SrFe2_2As2_2 and superconducting K0.4_{0.4}Sr0.6_{0.6}Fe2_2As2_2 (Tc=37T_c = 37 K) are reported. All four phonon modes (A1g_{1g} + B1g_{1g} + 2Eg_g) allowed by symmetry, are found and identified. Shell model gives reasonable description of the spectra. No detectable anomalies are observed near the tetragonal-to-orthorhombic transition in SrFe2_2As2_2 or the superconducting transition in K0.4_{0.4}Sr0.6_{0.6}Fe2_2As2_2.Comment: 4 pages, 4 figures, 2 table

    Towards a Practical Behavior Analytic Multitiered Consultation Model for Early Childhood Educators

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    Early childhood educators are in a critical position to support young children’s social-emotional, behavioral, and learning development, which can be accomplished through consistent use of evidence-based practices delivered in day-to-day interactions. However, early childhood educators may require support for implementing evidence-based practices. The purpose of this paper is to introduce a novel form of behavioral consultation for early childhood educators. Specifically, a behavior analytic multitiered consultation model in which implementation supports become increasingly more intensive is described. Rationale, implementation, evidence-base, and implications for practice and research are described. Finally, this paper concludes with an empirical case study to illustrate this model’s implementation. This paper is also meant to serve as a call-to-action for researchers and practitioners to replicate this consultation model

    Stress reactivity and personality in extreme sport athletes: The psychobiology of BASE jumpers

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    AbstractThis is the first report of the psychobiology of stress in BASE jumpers, one of the most dangerous forms of extreme sport. We tested the hypotheses that indicators of emotional style (temperament) predict salivary cortisol reactivity, whereas indicators of intentional goal-setting (persistence and character) predict salivary alpha-amylase reactivity during BASE jumping. Ninety-eight subjects completed the Temperament and Character Inventory (TCI) the day before the jump, and 77 also gave salivary samples at baseline, pre-jump on the bridge over the New River Gorge, and post-jump upon landing. Overall BASE jumpers are highly resilient individuals who are highly self-directed, persistent, and risk-taking, but they are heterogeneous in their motives and stress reactivity in the Hypothalamic-Pituitary-Adrenal (HPA) stress system (cortisol reactivity) and the sympathetic arousal system (alpha-amylase reactivity). Three classes of jumpers were identified using latent class analysis based on their personality profiles, prior jumping experience, and levels of cortisol and alpha-amylase at all three time points. “Masterful” jumpers (class 1) had a strong sense of self-directedness and mastery, extensive prior experience, and had little alpha-amylase reactivity and average cortisol reactivity. “Trustful” jumpers (class 2) were highly cooperative and trustful individuals who had little cortisol reactivity coincident with the social support they experienced prior to jumping. “Courageous” jumpers (class 3) were determined despite anxiety and inexperience, and they had high sympathetic reactivity but average cortisol activation. We conclude that trusting social attachment (Reward Dependence) and not jumping experience predicted low cortisol reactivity, whereas persistence (determination) and not jumping experience predicted high alpha-amylase reactivity

    Application of the seven-factor-model of personality to an Italian preschool sample

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    OBJECTIVE: Advances in dimensional assessment of children in healthy and clinical populations has renewed interest in the study of temperament. Cloninger's Temperament and Character Inventory (TCI) has shown high reliability and internal consistency. Adult and adolescent versions have been translated into a number of languages and validated in cross-cultural studies worldwide. To date only one preschool-TCI-based study has been conducted in early infancy with teachers as observers. The present study is aimed to test an Italian Preschool version of the Temperament and Character Inventory (PsTCI). This is the first replication and the first validation study of TCI on preschoolers with parents as observers. METHODS: 395 preschool children, recruited from pediatric communities and day-care centres throughout Italy, participated in the study. Parents of each child enrolled in the study and completed a PsTCI about the child. Standard psychometric tests of reliability and validation were performed. RESULTS: Exploratory factor analyses demonstrated the presence of distinct domains for temperament and character. TCI dimensions had good internal consistency with Cronbach's alpha ranging values (|0.60|-|0.81|). Gender differences were found for Harm Avoidance (β=-0.186; p≤0.001) and Self-Directedness (β=-0.216; p≤0.01), and accounted for 5-35arm-38-702- of the observed variance. CONCLUSION: The present work suggests the psychological complexity of Cloninger's model and confirms its application in pre-school children from diverse environmental and cultural backgrounds. The results confirm that Cloninger's instrument for temperament and character evaluations can also be used with different observers and highlight the importance of considering cultural and demographic differences in the assessment of temperament and character in preschoolers

    Uncovering the complex genetics of human temperament

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    Experimental studies of learning suggest that human temperament may depend on the molecular mechanisms for associative conditioning, which are highly conserved in animals. The main genetic pathways for associative conditioning are known in experimental animals, but have not been identified in prior genome-wide association studies (GWAS) of human temperament. We used a data-driven machine learning method for GWAS to uncover the complex genotypic-phenotypic networks and environmental interactions related to human temperament. In a discovery sample of 2149 healthy Finns, we identified sets of single-nucleotide polymorphisms (SNPs) that cluster within particular individuals (i.e., SNP sets) regardless of phenotype. Second, we identified 3 clusters of people with distinct temperament profiles measured by the Temperament and Character Inventory regardless of genotype. Third, we found 51 SNP sets that identified 736 gene loci and were significantly associated with temperament. The identified genes were enriched in pathways activated by associative conditioning in animals, including the ERK, PI3K, and PKC pathways. 74% of the identified genes were unique to a specific temperament profile. Environmental influences measured in childhood and adulthood had small but significant effects. We confirmed the replicability of the 51 Finnish SNP sets in healthy Korean (90%) and German samples (89%), as well as their associations with temperament. The identified SNPs explained nearly all the heritability expected in each sample (37-53%) despite variable cultures and environments. We conclude that human temperament is strongly influenced by more than 700 genes that modulate associative conditioning by molecular processes for synaptic plasticity and long-term memory
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