3,030 research outputs found

    Recent changes in U.S. family finances: evidence from the 1998 and 2001 Survey of Consumer Finances

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    Data from the Federal Reserve Board's Survey of Consumer Finances show a striking pattern of growth in family income and net worth between 1998 and 2001. Inflation-adjusted incomes of families rose broadly, although growth was fastest among the group of families whose income was higher than the median. The median value of family net worth grew faster than that of income, but as with income, the growth rates of net worth were fastest for groups above the median. The years between 1998 and 2001 also saw a rise in the proportion of families that own corporate equities either directly or indirectly (such as through mutual funds or retirement accounts); by 2001 the proportion exceeded 50 percent. The growth in the value of equity holdings helped push up financial assets as a share of total family assets despite a decline in the overall stock market that began in the second half of 2000. ; The level of debt carried by families rose over the period, but the expansion in equities and the increased values of principal residences and other assets were sufficient to reduce debt as a proportion of family assets. The typical share of family income devoted to debt repayment also fell over the period. For some groups, however--particularly those with relatively low levels of income and wealth--a concurrent rise in the frequency of late debt payments indicated that their ability to service their debts had deteriorated.Consumer behavior ; Saving and investment ; Income

    Viruses as co-factors for the initiation or exacerbation of lung fibrosis

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    Idiopathic pulmonary fibrosis (IPF) remains exactly that. The disease originates from an unknown cause, and little is known about the mechanisms of pathogenesis. While the disease is likely multi-factorial, evidence is accumulating to implicate viruses as co-factors (either as initiating or exacerbating agents) of fibrotic lung disease. This review summarizes the available clinical and experimental observations that form the basis for the hypothesis that viral infections may augment fibrotic responses. We review the data suggesting a link between hepatitis C virus, adenovirus, human cytomegalovirus and, in particular, the Epstein-Barr gammaherpesvirus, in IPF. In addition, we highlight the recent associations made between gammaherpesvirus infection and lung fibrosis in horses and discuss the various murine models that have been used to investigate the contribution of gammaherpesviruses to fibrotic progression. We review the work demonstrating that gammaherpesvirus infection of Th2-biased mice leads to multi-organ fibrosis and highlight studies showing that gammaherpesviral infections of mice either pre- or post-fibrotic challenge can augment the development of fibrosis. Finally, we discuss potential mechanisms whereby viral infections may amplify the development of fibrosis. While none of these studies prove causality, we believe the evidence suggests that viral infections should be considered as potential initiators or exacerbating agents in at least some cases of IPF and thereby justify further study

    Informing Recommended Makerspace Outcomes Through Linguistic Analytics

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    An after-school maker club collected student reflections on makerspace projects in different formats over two years: private written reflections captured in the 3D GameLab gamification platform and video-recorded reflections posted in the more social FlipGrid platform. Club mentors selected these documentation platforms on the basis of their motivational affordances thought to encourage club members to document their work. Transcribed documentation was analyzed using Linguistic Inquiry Word Count (LIWC) software to generate linguistic profiles for comparison. Differences between written and video-recorded documentation suggest: private, written documentation is more likely to capture evidence of cognitive processing and achievement- or risk-oriented drives, but may be more negative in tone; semi-public, video documentation is more likely to capture evidence of social affiliation-oriented drives and may be more positive in tone. Future research should investigate linguistic impacts given merged approaches of reflective writing for social spaces, or reflective writing in social groups

    Establishing a Virtual Makerspace for an Online Graduate Course: A Design Case

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    This design case discusses key steps taken to establish a virtual makerspace for students enrolled in an online graduate course on informal learning. Two key design decisions are elaborated around (a) the selection of appropriate projects and packaged materials that distance education students can receive by mail to participate in making, and (b) the choice of an online platform for distance education students to document their design processes for assessment purposes and peer interaction and learning. This design case is relevant to a variety of online communities who may wish to engage in maker activities as well as isolated face-to-face communities or individuals who may not have local mentors to support informal making and could, therefore, benefit from online connectivity to an expert or peer support. To promote replication of the design, materials and community tools to support making among geographically dispersed makers are detailed

    Collimated, single-pass atom source from a pulsed alkali metal dispenser for laser-cooling experiments

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    We have developed an improved scheme for loading atoms into a magneto-optical trap (MOT) from a directed alkali metal dispenser in < 10^-10 torr ultra-high vacuum conditions. A current-driven dispenser was surrounded with a cold absorbing "shroud" held at < 0 C, pumping rubidium atoms not directed into the MOT. This nearly eliminates background alkali atoms and reduces the detrimental rise in pressure normally associated with these devices. The system can be well-described as a current-controlled, rapidly-switched, two-temperature thermal beam, and was used to load a MOT with 3 x 10^8 atoms.Comment: 5 pages, 4 figure

    Cavity Nonlinear Optics at Low Photon Numbers from Collective Atomic Motion

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    We report on Kerr nonlinearity and dispersive optical bistability of a Fabry-Perot optical resonator due to the displacement of ultracold atoms trapped within. In the driven resonator, such collective motion is induced by optical forces acting upon up to 10510^5 87^{87}Rb atoms prepared in the lowest band of a one-dimensional intracavity optical lattice. The longevity of atomic motional coherence allows for strongly nonlinear optics at extremely low cavity photon numbers, as demonstrated by the observation of both branches of optical bistability at photon numbers below unity.Comment: 4 pages, 3 figures. Modifed following reviewer comment

    Ab initio molecular dynamics calculations of ion hydration free energies

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    We apply ab initio molecular dynamics (AIMD) methods in conjunction with the thermodynamic integration or "lambda-path" technique to compute the intrinsic hydration free energies of Li+, Cl-, and Ag+ ions. Using the Perdew-Burke-Ernzerhof functional, adapting methods developed for classical force field applications, and with consistent assumptions about surface potential (phi) contributions, we obtain absolute AIMD hydration free energies (Delta G(hyd)) within a few kcal/mol, or better than 4%, of Tissandier 's [J. Phys. Chem. A 102, 7787 (1998)] experimental values augmented with the SPC/E water model phi predictions. The sums of Li+/Cl- and Ag+/Cl- AIMD Delta G(hyd), which are not affected by surface potentials, are within 2.6% and 1.2 % of experimental values, respectively. We also report the free energy changes associated with the transition metal ion redox reaction Ag++Ni+-> Ag+Ni2+ in water. The predictions for this reaction suggest that existing estimates of Delta G(hyd) for unstable radiolysis intermediates such as Ni+ may need to be extensively revised.Comment: 18 pages, 8 figures. This version is essentially the one published in J. Chem. Phy
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