3,530 research outputs found

    Mother-toddler interaction patterns associated with maternal depression.

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    Journal ArticleInteractive coordination was observed in laboratory play interactions of pairs of 29 clinically depressed and 14 nondepressed mothers and their 13-29-month-old children (M = 18.9 months). Nondepressed mothers and their children displayed more interactive coordination than depressed-mother dyads (p < .001). Depressed mothers were less likely to repair interrupted interactions, and their toddlers were less likely to maintain interactions than nondepressed controls. Toddlers matched their nondepressed but not their depressed mothers' negative behavior rates. Results suggested that early interventions focus on training mothers to attend to, maintain, and repair mother-child interactions to more closely approximate normal levels of interactive coordination

    G-quadruplex structure and stability illuminated by 2-aminopurine phasor plots

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    The use of time-resolved fluorescence measurements in studies of telomeric G-quadruplex folding and stability has been hampered by the complexity of fluorescence lifetime distributions in solution. The application of phasor diagrams to the analysis of time-resolved fluorescence measurements, collected from either frequency-domain or time-domain instrumentation, allows for rapid characterization of complex lifetime distributions. Phasor diagrams are model-free graphical representations of transformed time-resolved fluorescence results. Simplification of complex fluorescent decays by phasor diagrams is demonstrated here using a 2-aminopurine substituted telomeric G-quadruplex sequence. The application of phasor diagrams to complex systems is discussed with comparisons to traditional non-linear regression model fitting. Phasor diagrams allow for the folding and stability of the telomeric G-quadruplex to be monitored in the presence of either sodium or potassium. Fluorescence lifetime measurements revealed multiple transitions upon folding of the telomeric G-quadruplex through the addition of potassium. Enzymatic digestion of the telomeric G-quadruplex structure, fluorescence quenching and Förster resonance energy transfer were also monitored through phasor diagrams. This work demonstrates the sensitivity of time-resolved methods for monitoring changes to the telomeric G-quadruplex and outlines the phasor diagram approach for analysis of complex time-resolved results that can be extended to other G-quadruplex and nucleic acid systems

    NASA-JSC antenna near-field measurement system

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    Work was completed on the near-field range control software. The capabilities of the data processing software were expanded with the addition of probe compensation. In addition, the user can process the measured data from the same computer terminal used for range control. The design of the laser metrology system was completed. It provides precise measruement of probe location during near-field measurements as well as position data for control of the translation beam and probe cart. A near-field range measurement system was designed, fabricated, and tested

    An example of persistent microstructure in a long rain event

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    A 2D video disdrometer (2DVD) probe was used to gather detailed drop measurements over a 770-min rain event. Accumulated totals of the rainfall and of the number of drops for each square centimeter showed persistent, significant correlated structures across the approximately 11 cm × 11 cm grid of the 2DVD. This is surprising because larger-scale studies suggest that the values in each square centimeter should be highly correlated with very little variation. Nevertheless, this correlation remains strikingly similar to what is observed at a coarser resolution, suggesting that it somehow scales with spatial resolution. However, because the correlation functions are not power laws, the origin of this scaling must be due to a factor other than fractal geometry. Analysis reveals that this occurs because of a filtering effect such that as the domain size (or resolution of a remote sensor) becomes finer, it is only the smaller wavelengths that contribute most to the variance so that the correlation function also scales. Consequently, correlated finescale structures can apparently occur even over 10 cm. This fine structure was also found for the kinetic energy and impact power of the rain, important for understanding the initiation of soil erosion. The patterns in the integrated parameters appeared to arise almost exclusively from patterns in the total number of drops with patterns in the drop sizes playing an insignificant role. Therefore, in future studies of rain it is recommended that the total number of drops be retained as a crucial variable

    On the variability of drop size distributions over areas

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    Past studies of the variability of drop size distributions (DSDs) have used moments of the distribution such as the mass-weighted mean drop size as proxies for the entire size distribution. In this study, however, the authors separate the total number of drops Nt from the DSD leaving the probability size distributions (PSDs); that is, DSD = Nt × PSD. The variability of the PSDs are then considered using the frequencies of size [P(D)] values at each different drop diameter P(PD | D) over an ensemble of observations collected using a network of 21 optical disdrometers. The relative dispersions RD of P(PD | D) over all the drop diameters are used as a measure of PSD variability. An intrinsic PSD is defined as an average over one or more instruments excluding zero drop counts. It is found that variability associated with an intrinsic PSD fails to characterize its true variability over an area. It is also shown that this variability is not due to sampling limitations but rather originates for physical reasons. Furthermore, this variability increases with the expansion of the network size and with increasing drop diameter. A physical explanation is that the network acts to integrate the Fourier transform of the spatial correlation function from smaller toward larger wavelengths as the network size increases so that the contributions to the variance by all spatial wavelengths being sampled also increases. Consequently, RDand, hence, PSD variability will increase as the size of the area increases

    Ideologies of time: How elite corporate actors engage the future

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    Our paper deals with how elite corporate actors in a Western capitalist-democratic society conceive of and prepare for the future. Paying attention to how senior officers of ten important Danish companies make sense of the future will help us to identify how particular temporal narratives are ideologically marked. This ideological dimension offers a common sense frame that is structured around a perceived inevitability of capitalism, a market economy as the basic organizational structure of the social and economic order, and an assumption of confident access to the future. Managers envisage their organization?s future and make plans for organizational action in a space where ?business as usual? reigns, and there is little engagement with the future as fundamentally open; as a time-yet-to-come. In using a conceptual lens inspired by the work of Fredric Jameson, we first explore the details of this presentism and a particular colonization of the future, and then linger over small disruptions in the narratives of our interviewees which point to what escapes or jars their common sense frame, explore the implicit meanings they assign to their agency, and also find clues and traces of temporal actions and strategies in their narratives that point to a subtly different engagement with time

    Identification of a novel retroviral gene unique to human immunodeficiency virus type 2 and simian immunodeficiency virus SIVMAC

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    Human and simian immunodeficiency-associated retroviruses are extraordinarily complex, containing at least five genes, tat, art, sor, R, and 3' orf, in addition to the structural genes gag, pol, and env. Recently, nucleotide sequence analysis of human immunodeficiency virus type 2 (HIV-2) and simian immunodeficiency virus SIVMAC revealed the existence of still another open reading frame, termed X, which is highly conserved between these two viruses but absent from HIV-1. In this report, we demonstrate for the first time that the X open reading frame represents a functional retroviral gene in both HIV-2 and SIVMAC and that it encodes a virion-associated protein of 14 and 12 kilodaltons, respectively. We also describe the production of recombinant TrpE/X fusion proteins in Escherichia coli and show that sera from some HIV-2-infected individuals specifically recognize these proteins

    Observations of Ultracool White Dwarfs

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    We present new spectroscopic and photometric measurements of the white dwarfs LHS 3250 and WD 0346+246. Along with F351-50, these white dwarfs are the coolest ones known, all with effective temperatures below 4000 K. Their membership in the Galactic halo population is discussed, and detailed comparisons of all three objects with new atmosphere models are presented. The new models consider the effects of mixed H/He atmospheres and indicate that WD 0346+246 and F351-50 have predominantly helium atmospheres with only traces of hydrogen. LHS 3250 may be a double degenerate whose average radiative temperature is between 2000 and 4000 K, but the new models fail to explain this object
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