1,002 research outputs found

    Social Security Reform and National Saving in an Era of Budget Surpluses

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    macroeconomics, Social Security, Social Security Reform, National Saving, Budget Surplus

    Fiscal Policy and Social Security Policy During the 1990s

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    This paper reviews the course of fiscal policy and Social Security policy during the 1990s. The 1990s witnessed two fundamental changes in U.S. fiscal policy: a dramatic improvement in the current and projected budget balance, and a shift to a new political consensus in favor of balancing the budget excluding Social Security rather than the unified budget. The dramatic improvement in the budget outlook stemmed both from favorable developments in the economic environment and from deliberate policy actions that reduced budget deficits and later did not spend down the surpluses. In contrast, the 1990s did not witness significant changes in Social Security policy, although alternative visions of Social Security reform received tremendous analytic and popular attention. The 1994-1996 Advisory Council on Social Security presented three reform plans that placed important emphasis on additional prefunding. Each involved some form of investment in equities either centrally, through the trust fund, or in a decentralized manner, through individual accounts. Late in the decade, with the emergence of on-budget surpluses, the possibility of general revenue contributions to the Social Security system came under serious consideration. In the end, President Clinton decided to pursue Social Security reform based on general revenue contributions to the trust fund and centralized investment in equities rather than creating individual accounts, but his proposal was not adopted.

    An Engineered Nonsense \u3cem\u3eURA3\u3c/em\u3e Allele Provides a Versatile System to Detect the Presence, Absence and Appearance of the [em\u3ePSI\u3c/em\u3e\u3csup\u3e+\u3c/sup\u3e] Prion in \u3cem\u3eSaccharomyces cerevisiae\u3c/em\u3e

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    Common methods to identify yeast cells containing the prion form of the Sup35 translation termination factor, [PSI+], involve a nonsense suppressor phenotype. Decreased function of Sup35p in [PSI+] cells leads to readthrough of certain nonsense mutations in a few auxotrophic markers, for example, ade1-14. This readthrough results in growth on adenine deficient media. While this powerful tool has dramatically facilitated the study of [PSI+], it is limited to a narrow range of laboratory strains and cannot easily be used to screen for cells that have lost the [PSI+] prion. Therefore we have engineered a nonsense mutation in the widely used URA3 gene, termed the ura3-14 allele. Introduction of the ura3-14 allele into an array of genetic backgrounds, carrying a loss-of-function URA3 mutation and [PSI+], allows for growth on media lacking uracil, indicative of decreased translational termination efficiency. This ura3-14 allele is able to distinguish various forms of the [PSI+] prion, called variants and is able to detect the de novo appearance of [PSI+] in strains carrying the prion form of Rnq1p, [PIN+]. Furthermore, 5-fluoorotic acid, which kills cells making functional Ura3p, provides a means to select for [psi−] derivatives in a population of [PSI+] cells marked with the ura3-14 allele, making this system much more versatile than previous methods

    Most, but not All, Yeast Strains in the Deletion Library Contain the [PIN+] Prion

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    The yeast deletion library is a collection of over 5100 single gene deletions that has been widely used by the yeast community. The presence of a non-Mendelian element, such as a prion, within this library could affect the outcome of many large-scale genomic studies. We previously showed that the deletion library parent strain contained the [PIN+] prion. [PIN+] is the misfolded infectious prion form of the Rnq1 protein that displays distinct fluorescent foci in the presence of RNQ1–GFP and exists in different physical conformations, called variants. Here, we show that over 97% of the library deletion strains are [PIN+]. Of the 141 remaining strains that have completely (58) or partially (83) lost [PIN+], 139 deletions were able to efficiently maintain three different [PIN+] variants despite extensive growth and storage at 4 °C. One strain, cue2Δ, displayed an alteration in the RNQ1–GFP fluorescent shape, but the Rnq1p prion aggregate shows no biochemical differences from the wild-type. Only strains containing a deletion of either HSP104 or RNQ1 are unable to maintain [PIN+], indicating that 5153 non-essential genes are not required for [PIN+] propagation. Copyright © 2009 John Wiley & Sons, Ltd

    The heats of formation of the haloacetylenes XCCY [X, Y = H, F, Cl]: basis set limit ab initio results and thermochemical analysis

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    The heats of formation of haloacetylenes are evaluated using the recent W1 and W2 ab initio computational thermochemistry methods. These calculations involve CCSD and CCSD(T) coupled cluster methods, basis sets of up to spdfgh quality, extrapolations to the one-particle basis set limit, and contributions of inner-shell correlation, scalar relativistic effects, and (where relevant) first-order spin-orbit coupling. The heats of formation determined using W2 theory are: \hof(HCCH) = 54.48 kcal/mol, \hof(HCCF) = 25.15 kcal/mol, \hof(FCCF) = 1.38 kcal/mol, \hof(HCCCl) = 54.83 kcal/mol, \hof(ClCCCl) = 56.21 kcal/mol, and \hof(FCCCl) = 28.47 kcal/mol. Enthalpies of hydrogenation and destabilization energies relative to acetylene were obtained at the W1 level of theory. So doing we find the following destabilization order for acetylenes: FCCF >> ClCCF >> HCCF >> ClCCCl >> HCCCl >> HCCH. By a combination of W1 theory and isodesmic reactions, we show that the generally accepted heat of formation of 1,2-dichloroethane should be revised to -31.8±\pm0.6 kcal/mol, in excellent agreement with a very recent critically evaluated review. The performance of compound thermochemistry schemes such as G2, G3, G3X and CBS-QB3 theories has been analyzed.Comment: Mol. Phys., in press (E. R. Davidson issue

    The Effect of Natural Mulches on Crop Performance, Weed Suppression and Biochemical Constituents of Catnip and St. John\u27s Wort

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    Because of expanding markets for high-value niche crops, opportunities have increased for the production of medicinal herbs in the USA. An experiment was conducted in 2001 and 2002 near Gilbert, IA, to study crop performance, weed suppression, and environmental conditions associated with the use of several organic mulches in the production of two herbs, catnip (Nepeta cataria L.) and St. John\u27s wort (Hypericum perforatum L. ‘Helos’). Treatments were arranged in a completely randomized design and included a positive (hand-weeded) control, a negative (nonweeded) control, oat straw, a flax straw mat, and a nonwoven wool mat. Catnip plant height was significantly greater in the oat straw than the other treatments at 4 wk through 6 wk in 2001; at 4 to 8 wk in 2002, catnip plant height and width was significantly lower in the negative control compared with the other treatments. Catnip yield was significantly higher in the flax straw mat than all other treatments in 2001. In 2002, St. John\u27s wort yields were not statistically different in any treatments. All weed management treatments had significantly fewer weeds than the non-weeded rows in 2002. Total weed density comparisons in each crop from 2 yr showed fewer weeds present in the flax straw and wool mat treatments compared with positive control plots. There was no significant weed management treatment effect on the concentration of the target compounds, nepetalactone in catnip and pseudohypericin–hypericin in St. John\u27s wort, although there was a trend toward higher concentrations in the flax straw treatment

    Integrating Organic Soybean Production following Conservation Reserve Program (CRP) Land into Sustainable Farming Systems

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    Organic farming has increased to an $8 billion industry in the United States and continues to expand approximately 20% annually. In Iowa alone, organic acreage has increased from 13,000 acres in 1995 to 150,000 in 1999. Across the North Central region, there has been great interest in planting organic soybeans on Conservation Reserve Program (CRP) land, where up to a 400% premium can be obtained compared with conventionally raised soybeans. Regulation of soil organic matter through additions of plant residues and proper crop rotations will determine the long-term sustainability of the system
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