33 research outputs found
Watching young children 'play' with information technology : everyday life information seeking in the home
Research on how young children use information to orient themselves in daily life and to solve problems (known as everyday life information seeking or ELIS) has not been conducted, in-depth, in information science. This exploratory observation study examines how 15 Australian preschool children (aged three to five) used information technologies in their homes to orient themselves in daily life and to solve problems. Children engaged in various ways with the digital technologies available to them and with parents and siblings during play activities. The results explore the value of artistic play, sociodramatic play, and early literacy and numeracy activities in shaping young children's ‘way of life’ and ‘mastery of life’ as outlined in Savolainen's (1995) ELIS model. Observed technology engagement provided an opportunity to explore children's social worlds and the ways that they gathered information during technology play that will inform future learning activities and support child development. By using ELIS theory as an analytic lens, the results demonstrate how children's developmental play with technology tools helps them to internalize social and cultural norms. The data also point to the type of capital available to children and how that capital contributes to children's emerging information practices
Expression and Purification of a Cleavable Recombinant Fortilin from \u3ci\u3eEscherichia coli\u3c/i\u3e for Structure Activity Studies
Complications related to atherosclerosis account for approximately 1 in 4 deaths in the United States and treatment has focused on lowering serum LDL-cholesterol levels with statins. However, approximately 50% of those diagnosed with atherosclerosis have blood cholesterol levels within normal parameters. Human fortilin is an anti-apoptotic protein and a factor in macrophage-mediated atherosclerosis and is hypothesized to protect inflammatory macrophages from apoptosis, leading to subsequent cardiac pathogenesis. Fortilin is unique because it provides a novel drug target for atherosclerosis that goes beyond lowering cholesterol and utilization of a solution nuclear magnetic resonance (NMR) spectroscopy, structure-based drug discovery approach requires milligram quantities of pure, bioactive, recombinant fortilin. Here, we designed expression constructs with different affinity tags and protease cleavage sites to find optimal conditions to obtain the quantity and purity of protein necessary for structure activity relationship studies. Plasmids encoding fortilin with maltose binding protein (MBP), 6-histidine (6His) and glutathione-S-transferase (GST), N- terminal affinity tags were expressed and purified from Escherichia coli (E. coli). Cleavage sites with tobacco etch virus (TEV) protease and human rhinovirus (HRV) 3C protease were assessed. Despite high levels of expression of soluble protein, the fusion constructs were resistant to proteinases without the inclusion of amino acids between the cleavage site and N-terminus. We surveyed constructs with increasing lengths of glycine/serine (GGS) linkers between the cleavage site and fortilin and found that inclusion of at least one GGS insert led to successful protease cleavage and pure fortilin with conserved binding to calcium as measured by NMR
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Sources and characteristics of summertime organic aerosol in the Colorado Front Range: perspective from measurements and WRF-Chem modeling
Abstract. The evolution of organic aerosols (OAs) and their precursors in the boundary layer (BL) of the Colorado Front Range during the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ, July–August 2014) was analyzed by in situ measurements and chemical transport modeling. Measurements indicated significant production of secondary OA (SOA), with enhancement ratio of OA with respect to carbon monoxide (CO) reaching 0.085±0.003 µg m−3 ppbv−1. At background mixing ratios of CO, up to  ∼  1.8 µg m−3 background OA was observed, suggesting significant non-combustion contribution to OA in the Front Range. The mean concentration of OA in plumes with a high influence of oil and natural gas (O&G) emissions was  ∼  40 % higher than in urban-influenced plumes. Positive matrix factorization (PMF) confirmed a dominant contribution of secondary, oxygenated OA (OOA) in the boundary layer instead of fresh, hydrocarbon-like OA (HOA). Combinations of primary OA (POA) volatility assumptions, aging of semi-volatile species, and different emission estimates from the O&G sector were used in the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) simulation scenarios. The assumption of semi-volatile POA resulted in greater than a factor of 10 lower POA concentrations compared to PMF-resolved HOA. Including top-down modified O&G emissions resulted in substantially better agreements in modeled ethane, toluene, hydroxyl radical, and ozone compared to measurements in the high-O&G-influenced plumes. By including emissions from the O&G sector using the top-down approach, it was estimated that the O&G sector contributed to  <  5 % of total OA, but up to 38 % of anthropogenic SOA (aSOA) in the region. The best agreement between the measured and simulated median OA was achieved by limiting the extent of biogenic hydrocarbon aging and consequently biogenic SOA (bSOA) production. Despite a lower production of bSOA in this scenario, contribution of bSOA to total SOA remained high at 40–54 %. Future studies aiming at a better emissions characterization of POA and intermediate-volatility organic compounds (IVOCs) from the O&G sector are valuable
Multiwavelength Observations of A0620-00 in Quiescence
[Abridged.] We present multiwavelength observations of the black hole binary
system, A0620-00. Using the Cosmic Origins Spectrograph on the Hubble Space
Telescope, we have obtained the first FUV spectrum of A0620-00. The observed
spectrum is flat in the FUV and very faint (with continuum fluxes \simeq 1e -
17 ergs/cm^2/s/A). We compiled the dereddened, broadband spectral energy
distribution of A0620-00 and compared it to previous SEDs as well as
theoretical models. The SEDs show that the source varies at all wavelengths for
which we have multiple samples. Contrary to previous observations, the
optical-UV spectrum does not continue to drop to shorter wavelengths, but
instead shows a recovery and an increasingly blue spectrum in the FUV. We
created an optical-UV spectrum of A0620-00 with the donor star contribution
removed. The non-stellar spectrum peaks at \simeq3000 {\deg}A. The peak can be
fit with a T=10,000 K blackbody with a small emitting area, probably
originating in the hot spot where the accretion stream impacts the outer disk.
However, one or more components in addition to the blackbody are needed to fit
the FUV upturn and the red optical fluxes in the optical-UV spectrum. By
comparing the mass accretion rate determined from the hot spot luminosity to
the mean accretion rate inferred from the outburst history, we find that the
latter is an order of magnitude smaller than the former, indicating that
\sim90% of the accreted mass must be lost from the system if the predictions of
the disk instability model and the estimated interoutburst interval are
correct. The mass accretion rate at the hot spot is 10^5 the accretion rate at
the black hole inferred from the X-ray luminosity. To reconcile these requires
that outflows carry away virtually all of the accreted mass, a very low rate of
mass transfer from the outer cold disk into the inner hot region, and/or
radiatively inefficient accretion.Comment: ApJ, accepte
Constraints from observations and modeling on atmosphere-surface exchange of mercury in eastern North America
Atmosphere-surface exchange of mercury, although a critical component of its global cycle, is currently poorly constrained. Here we use the GEOS-Chem chemical transport model to interpret atmospheric Hg-0 (gaseous elemental mercury) data collected during the 2013 summer Nitrogen, Oxidants, Mercury and Aerosol Distributions, Sources and Sinks (NOMADSS) aircraft campaign as well as ground-and ship-based observations in terms of their constraints on the atmosphere-surface exchange of Hg-0 over eastern North America. Model-observation comparison suggests that the Northwest Atlantic may be a net source of Hg-0, with high evasion fluxes in summer (our best sensitivity simulation shows an average oceanic Hg-0 flux of 3.3 ng m(-2) h(-1) over the Northwest Atlantic), while the terrestrial ecosystem in the summer of the eastern United States is likely a net sink of Hg-0 (our best sensitivity simulation shows an average terrestrial Hg-0 flux of -0.6 ng m(-2) h(-1) over the eastern United States). The inferred high Hg-0 fluxes from the Northwest Atlantic may result from high wet deposition fluxes of oxidized Hg, which are in turn related to high precipitation rates in this region. We also find that increasing simulated terrestrial fluxes of Hg-0 in spring compared to other seasons can better reproduce observed seasonal variability of Hg-0 concentration at ground-based sites in eastern North America.Peer reviewe
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Habit2: A stand-alone software solution for presenting stimuli and recording infant looking times in order to study infant development
Many aspects of infant development are assessed using infant looking times to visual and audiovisual stimuli. In this article, we describe a stand-alone software package that allows simultaneous stimulus presentation to infants and recording of their looking times via a keypress by a human observer. The software was developed to run both on 64-bit Intel-based Macs running Mac OS/X 10.10 (Yosemite) or later and on 64-bit Windows 7 and 10. It can present a variety of visual and/or auditory stimuli; is customizable with respect to how trials are initiated, how trial lengths are defined, and the phases of the experiment; and can be used to record looking times online or after the fact, as well as to assess the reliability of coding. The software is freely available at http://habit.ucdavis.edu
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Cues to individuation facilitate 6-month-old infants' visual short-term memory.
Infants' ability to perform visual short-term memory (VSTM) tasks develops rapidly between 6 and 8 months. Here we tested the hypothesis that infants' VSTM performance is influenced by their ability to individuate simultaneously presented objects. We used a one-shot change detection task to ask whether 6-month-old infants (N = 47) would detect a change in the color of 1 item in a 2-item array when the stimulus context facilitated individuation of the items. In Experiment 1 the 2 items in the display differed in shape and color and in Experiment 2 the onset and offset times of the 2 items differed. In both experiments, 6-month-old infants detected a change, contrasting with previous results. Thus, young infants' encoding of information about individual items in multiple-item arrays is related to their ability to individuate those items. (PsycINFO Database Record (c) 2019 APA, all rights reserved)
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Infant Eye Gaze While Viewing Dynamic Faces
Research using eye tracking methods has revealed that when viewing faces, between 6 to 10 months of age, infants begin to shift visual attention from the eye region to the mouth region. Moreover, this shift varies with stimulus characteristics and infants' experience with faces and languages. The current study examined the eye movements of a racially diverse sample of 98 infants between 7.5 and 10.5 months of age as they viewed movies of White and Asian American women reciting a nursery rhyme (the auditory component of the movies was replaced with music to eliminate the influence of the speech on infants' looking behavior). Using an analytic approach inspired by the multiverse analysis approach, several measures from infants' eye gaze were examined to identify patterns that were robust across different analyses. Although in general infants preferred the lower regions of the faces, i.e., the region containing the mouth, this preference depended on the stimulus characteristics and was stronger for infants whose typical experience included faces of more races and for infants who were exposed to multiple languages. These results show how we can leverage the richness of eye tracking data with infants to add to our understanding of the factors that influence infants' visual exploration of faces