Seniors and Information Technology: A MIS-Fit?

The “digital divide” between the haves and have-nots in society continues to draw attention in traditional media outlets as well as academic research. Those yearning to join the computer revolution comprise several groups defined by wealth, ethnicity, country (even regions of countries), and age. While there has been research into the digital divide in all of these areas, the focus of this paper is Information Technology (IT) use by the elderly, or our senior citizens. Our interest in this group stems from the dynamic interaction of two forces: 1) senior populations are growing in percentage and sheer number both in the United States and internationally; and 2) as a group, the elderly have more disposable income to spend on IT than their younger counterparts. In order to coordinate our research agenda, the current investigation presents a framework that delineates scholarly inquiry into this topic by the elements of the framework. We look at what has been done, and what we feel needs to be done, in order to incorporate an important demographic group into the mainstream of computing society: our seniors

Phonon Band Structure and Thermal Transport Correlation in a Layered Diatomic Crystal

To elucidate the relationship between a crystal's structure, its thermal conductivity, and its phonon dispersion characteristics, an analysis is conducted on layered diatomic Lennard-Jones crystals with various mass ratios. Lattice dynamics theory and molecular dynamics simulations are used to predict the phonon dispersion curves and the thermal conductivity. The layered structure generates directionally dependent thermal conductivities lower than those predicted by density trends alone. The dispersion characteristics are quantified using a set of novel band diagram metrics, which are used to assess the contributions of acoustic phonons and optical phonons to the thermal conductivity. The thermal conductivity increases as the extent of the acoustic modes increases, and decreases as the extent of the stop bands increases. The sensitivity of the thermal conductivity to the band diagram metrics is highest at low temperatures, where there is less anharmonic scattering, indicating that dispersion plays a more prominent role in thermal transport in that regime. We propose that the dispersion metrics (i) provide an indirect measure of the relative contributions of dispersion and anharmonic scattering to the thermal transport, and (ii) uncouple the standard thermal conductivity structure-property relation to that of structure-dispersion and dispersion-property relations, providing opportunities for better understanding of the underlying physical mechanisms and a potential tool for material design.Comment: 30 pages, 10 figure

Flavor Asymmetry of the Nucleon Sea: Consequences for Dilepton Production

Parton distributions derived from a chiral quark model that generates an excess of down quarks and antiquarks in the proton's sea satisfactorily describe the measured yields of muon pairs produced in proton-nucleus collisions. Comparison of dilepton yields from hydrogen and deuterium targets promises greater sensitivity to the predicted flavor asymmetry.Comment: 11 pages, REVTEX, (Three PostScript figures available by anonymous ftp from fnth06.fnal.gov in directory /pub/Fermilab-Pub/92.264.) FERMILAB-PUB-92/264--T LBL-3298

Asymmetrical distribution of non-conserved regulatory sequences at PHOX2B is reflected at the ENCODE loci and illuminates a possible genome-wide trend

<p>Abstract</p> <p>Background</p> <p>Transcriptional regulatory elements are central to development and interspecific phenotypic variation. Current regulatory element prediction tools rely heavily upon conservation for prediction of putative elements. Recent <it>in vitro </it>observations from the ENCODE project combined with <it>in vivo </it>analyses at the zebrafish <it>phox2b </it>locus suggests that a significant fraction of regulatory elements may fall below commonly applied metrics of conservation. We propose to explore these observations <it>in vivo </it>at the human <it>PHOX2B </it>locus, and also evaluate the potential evidence for genome-wide applicability of these observations through a novel analysis of extant data.</p> <p>Results</p> <p>Transposon-based transgenic analysis utilizing a tiling path proximal to human <it>PHOX2B </it>in zebrafish recapitulates the observations at the zebrafish <it>phox2b </it>locus of both conserved and non-conserved regulatory elements. Analysis of human sequences conserved with previously identified zebrafish <it>phox2b </it>regulatory elements demonstrates that the orthologous sequences exhibit overlapping regulatory control. Additionally, analysis of non-conserved sequences scattered over 135 kb 5' to <it>PHOX2B</it>, provides evidence of non-conserved regulatory elements positively biased with close proximity to the gene. Furthermore, we provide a novel analysis of data from the ENCODE project, finding a non-uniform distribution of regulatory elements consistent with our <it>in vivo </it>observations at <it>PHOX2B</it>. These observations remain largely unchanged when one accounts for the sequence repeat content of the assayed intervals, when the intervals are sub-classified by biological role (developmental versus non-developmental), or by gene density (gene desert versus non-gene desert).</p> <p>Conclusion</p> <p>While regulatory elements frequently display evidence of evolutionary conservation, a fraction appears to be undetected by current metrics of conservation. <it>In vivo </it>observations at the <it>PHOX2B </it>locus, supported by our analyses of <it>in vitro </it>data from the ENCODE project, suggest that the risk of excluding non-conserved sequences in a search for regulatory elements may decrease as distance from the gene increases. Our data combined with the ENCODE data suggests that this may represent a genome wide trend.</p

Phonon Transport Across a Vacuum Gap

Phonon transport across a silicon/vacuum-gap/silicon structure is modeled using lattice dynamics calculations and Landauer theory. The phonons transmit thermal energy across the vacuum gap via atomic interactions between the leads. Because the incident phonons do not encounter a classically impenetrable potential barrier, this mechanism is not a tunneling phenomenon. While some incident phonons transmit across the vacuum gap and remain in their original mode, many are annihilated and excite different modes. We show that the heat flux due to phonon transport can be 4 orders of magnitude larger than that due to photon transport predicted from near-field radiation theory

PhD from the University of South Carolina. He has published research in the

Abstract: The worldwide elderly population continues to grow, in terms of raw numbers as well as their use of computers and the internet. These facts notwithstanding, it appears that vendors of information technology products, both hardware and software, have largely ignored seniors. Research has shown that these &apos;silver surfers&apos; are one of that fastest-growing user groups online and, furthermore, have more disposable income than any other segment of modern society. This paper investigates elderly computer and internet usage by incorporating the results of three separate research streams that have reported on this topic. Implications for both practice and research are presented