123 research outputs found

    Modeling the normal:abnormal spectrum of early childhood internalizing behaviors: A clinical-developmental approach for the Multidimensional Assessment Profiles Internalizing Dimensions

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    BACKGROUND: We expanded the Multidimensional Assessment Profiles (MAPS) Scales developmental specification model to characterize the normal:abnormal spectrum of internalizing (anxious and depressive) behaviors in early childhood via the MAPS-Internalizing (MAPS-INT) scale. METHODS: The MAPS-INT item pool was generated based on clinical expertise and prior research. Analyses were conducted on a sub-sample of families (n = 183) from the diverse When to Worry early childhood sample. RESULTS: Normal:abnormal descriptive patterns for both anxious and depressive behaviors were consistent with prior work: (1) extremes of normative variation are abnormal when very frequent; and (2) pathognomonic indicators that most children do not engage in and are abnormal, even if infrequent. Factor analysis revealed a two-factor MAPS-INT Anxious Behaviors structure (Fearful-Worried and Separation Distress) and a unidimensional MAPS-INT Depressive Behaviors factor with good fit and good-to-excellent test-retest reliability and validity. CONCLUSIONS: We characterized the normal:abnormal spectrum of internalizing behaviors in early childhood via the MAPS-INT. Future research in larger representative samples can replicate and extend findings, including clinical thresholds and predictive utility. The MAPS-INT helps lay the groundwork for dimensional characterization of the internalizing spectrum to advance neurodevelopmental approaches to emergent psychopathology and its earlier identification

    The inverse-trans-influence in tetravalent lanthanide and actinide bis(carbene) complexes

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    Across the periodic table the trans-influence operates, whereby tightly bonded ligands selectively lengthen mutually trans metal–ligand bonds. Conversely, in high oxidation state actinide complexes the inverse-trans-influence operates, where normally cis strongly donating ligands instead reside trans and actually reinforce each other. However, because the inversetrans-influence is restricted to high-valent actinyls and a few uranium(V/VI) complexes, it has had limited scope in an area with few unifying rules. Here we report tetravalent cerium, uranium and thorium bis(carbene) complexes with trans C¼M¼C cores where experimental and theoretical data suggest the presence of an inverse-trans-influence. Studies of hypothetical praseodymium(IV) and terbium(IV) analogues suggest the inverse-trans-influence may extend to these ions but it also diminishes significantly as the 4f orbitals are populated. This work suggests that the inverse-trans-influence may occur beyond high oxidation state 5f metals and hence could encompass mid-range oxidation state actinides and lanthanides. Thus, the inverse-trans-influence might be a more general f-block principle

    Combined Experimental and Computational Studies on the Nature of Aromatic C−H Activation by Octahedral Ruthenium(II) Complexes: Evidence for σ-Bond Metathesis from Hammett Studies

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    Octahedral ruthenium complexes of the type TpRu(L)(NCMe)R [Tp = hydridotris(pyrazolyl)borate; R = alkyl or aryl; L = CO or PMe3] have been shown previously to initiate the C-H activation of aromatic substrates. In order to probe the nature of the C-H activation step, reaction rates have been theoretically obtained for the conversion of TpRu(L)(η2-C, C-C6H5X)Me to TpRu(L)(P-C6H4X) and CH4 where X is varied among Br, Cl, CN, F, H, NH2, NO 2, and OMe. A linear Hammett correlation is calculated with a positive p value of 2.6 for L = CO and 3.2 for L = PMe3. Calculated kinetic data for the aromatic C-H activations indicate that an electrophilic aromatic substitution mechanism is unlikely. While experiments cannot fully replicate the entire range of calculated Hammett plots, reactivity trends are consistent with the calculations that suggest activation barriers to overall metal-mediated arene C-H bond cleavage are reduced by the presence of electron-withdrawing groups in the position para to the site of activation. Previous mechanistic studies, as well as the structure and imaginary vibrational modes of the present transition states, validate that the C-H activation for this family of TpRu complexes occurs through a σ-bond metathesis-type pathway. © 2007 American Chemical Society

    Active Drumming Experience Increases Infants' Sensitivity to Audiovisual Synchrony during Observed Drumming Actions

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    In the current study, we examined the role of active experience on sensitivity to multisensory synchrony in six-month-old infants in a musical context. In the first of two experiments, we trained infants to produce a novel multimodal effect (i.e., a drum beat) and assessed the effects of this training, relative to no training, on their later perception of the synchrony between audio and visual presentation of the drumming action. In a second experiment, we then contrasted this active experience with the observation of drumming in order to test whether observation of the audiovisual effect was as effective for sensitivity to multimodal synchrony as active experience. Our results indicated that active experience provided a unique benefit above and beyond observational experience, providing insights on the embodied roots of (early) music perception and cognition

    Thermodynamics of addition of H-2, CO, N-2, and C-H bonds to M((PPr3)-Pr-i)(2)Cl (M = Ir, Rh) : an unprecedented metal-carbonyl bond strength

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    The thermodynamics of interconversion of various complexes containing the unit IrL*Cl-2 (L* = P(Pr-i)(3)) have been investigated by calorimetry and equilibrium measurements. These complexes span a wide range of configurations including four- and five-coordinate d(8) (IrL*2ClL', IrL*Cl-2(CO)(2)) and five- and six-coordinate d(6) (IrL*2ClRH and IrL*2ClRH(CO)). On the basis of kinetic experiments, a lower limit to the Ir-Nz bond dissociation enthalpy (BDE) of IrL*Cl-2(N-2) has been determined (36 kcal/mol). Using this value as an "anchor", in conjunction with the relative addition enthalpies obtained calorimetrically, it is possible to derive lower limits for the absolute exothermicities of H-2 (48 kcal/mol) and CO (72 kcal/mol) addition to IrL*Cl-2; estimates can also be made for the addition of benzene and acetylene C-H bonds. These values are unusually high; indeed, the magnitude of the Ir-CO BDE is unprecedented. In addition, kinetic methods have been used to determine a lower limit of 29 kcal/mol to the Rh-N-2 BDE of RhL*Cl-2(N-2). Combined with previous calorimetric measurements on rhodium complexes, this value permits the calculation of lower limits to the absolute exothermicities of addition to RhL*Cl-2 for numerous small molecules including H-2, CO, N-2, C2H4, and aldehydic C-H bonds. The results of electronic structure calculations (approximate DFT; PMe3 used to model (PPr3)-Pr-i) are in excellent agreement with the relative experimental enthalpies, while the absolute values calculated for addition to IrL2Cl are significantly greater than the experimentally determined lower limits. Addition of a methane C-H bond is calculated to be significantly less favorable than addition of benzene or acetylene C-H bonds, in accord with the fact that IrL*Cl-2(alkyl)H complexes have not been reported. The significant differences in the enthalpies of addition for these three types of C-H bonds are briefly analyzed
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