13,699 research outputs found

    Development of a 60 kW alternator for SNAP-8

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    Design and development testing of 60 kW alternator for SNAP

    Intergenerational Effects of the Distribution of Income and Wealth: The Utah Experience, 1850-1900

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    The relationship between the wealth or income of parents and children is an important economic issue in both positive and normative senses. In this paper, we estimate elasticities of sons' income or wealth with respect to the wealth of their fathers for a sample of households in nineteenth century Utah. We find the elasticity relating the wealth of fathers to sons to range from .10 to .34 depending on the variables held constant such as occupation, age and residence. Elasticities based on observation of the wealth of fathers and sons in the same year were higher than those based on a lagged value of the fathers' wealth. The death of the father prior to observation of the sons' wealth increased the elasticity about three fold. The elasticity between the income of sons and wealth of fathers was low (.09 to .21) but significant even though the sons' incomes were observed fifteen years after the wealth of fathers. In general, the data suggest a persistent relationship between the economic status of parents and their children with substantial regression toward the mean so that an economic elite was unlikely to be based upon intergenerational transmission of economic success.

    Wealth Mobility: The Missing Element

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    We consider the problems that may arise when cross sectional data alone are used for inferences about individual welfare, the existence of elites, the possibilities of class boundaries, the openness of a society, etc. We also consider problems with alternative measures of socio-economic position. We then use a sample of 2400 households observed over one or two decade intervals together with data on the population of households at each observation point to examine mobility within the distribution of wealth for an almost closed economy, Utah, 1850-1870. We use information on households to examine those characteristics that contribute to mobility. We find considerable mobility, much apparently stochastic, within quite highly skewed distributions of wealth that also exhibit increasing inequality through time.

    Unobservable Family and Individual Contributions to the Distributions ofIncome and Wealth

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    This paper uses a data set composed of combinations of full brothers, half brothers as well as fathers and sons to measure the effect of common family background on households'income and wealth. While the data is drawn from a nineteenth century population, the intra-class correlation (after the effects of age, occupation, nativity, residence and duration in the economy have been removed) for income ranges from .13 to .18 which is similar to that found in modern samples. Intra-class correlations for wealth are significantly higher (.18 to .35) than those for income. The addition of fathers' observed characteristics to the sweeping regressions reduces the unobserved common background effect shared by brothers by about twenty percent.The intra-class correlations of half brothers were lower than those observed for full brothers though the small differences between the two groups suggest that fathers played a dominant role in the transmission of the common family effect. Unobserved background was decomposed into individual and family effects by a variance components procedure. The individual effect was dominant for income while the family effect was dominant for wealth.

    The 70 S monosome accumulation and in vitro initiation complex formation by Escherichia coli ribosomes at 5 C

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    The inhibition of translation which is observed after shifting Escherichia coli to low temperature was investigated. 70 S ribosomes were isolated from E. coli 8 hours after a shift to 5 C synthesized protein in the absence of added mRNA (i.e., endogenous protein synthesis by 70 S monosomes) at a rate which was three times greater than the rate of endogenous protein synthesis by 70 S ribosomes which were isolated at the time of the shift to 5 C. Calculations based on the rates of endogenous protein synthesis and polyphenylalanine synthesis indicate that 70 S monosomes comprise only 0.1% of the total E. coli 70 S ribosome population after 8 hours at 5 c. Experiments designed to test initiation complex formation on ApUpG or formaldehyde treated MS-2 viral RNA demonstrated that, although the rate of formation of 30 S initiation complexes was not inhibited, the rate of formation of active 70 S initiation complexes, able to react with puromycin, was inhibited to a great extent at 5 C. A model depicting the effects of low temperature on the E. coli translation system is proposed

    Design and Development of a SNAP-8 Mercury Pump Motor Assembly

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    Design and performance of mercury pump motor for SNAP 8 electrical generato

    The general form of supersymmetric solutions of N=(1,0) U(1) and SU(2) gauged supergravities in six dimensions

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    We obtain necessary and sufficient conditions for a supersymmetric field configuration in the N=(1,0) U(1) or SU(2) gauged supergravities in six dimensions, and impose the field equations on this general ansatz. It is found that any supersymmetric solution is associated to an SU(2)⋉R4SU(2)\ltimes \mathbb{R}^4 structure. The structure is characterized by a null Killing vector which induces a natural 2+4 split of the six dimensional spacetime. A suitable combination of the field equations implies that the scalar curvature of the four dimensional Riemannian part, referred to as the base, obeys a second order differential equation. Bosonic fluxes introduce torsion terms that deform the SU(2)⋉R4SU(2)\ltimes\mathbb{R}^4 structure away from a covariantly constant one. The most general structure can be classified in terms of its intrinsic torsion. For a large class of solutions the gauge field strengths admit a simple geometrical interpretation: in the U(1) theory the base is K\"{a}hler, and the gauge field strength is the Ricci form; in the SU(2) theory, the gauge field strengths are identified with the curvatures of the left hand spin bundle of the base. We employ our general ansatz to construct new supersymmetric solutions; we show that the U(1) theory admits a symmetric Cahen-Wallach4×S2_4\times S^2 solution together with a compactifying pp-wave. The SU(2) theory admits a black string, whose near horizon limit is AdS3×S3AdS_3\times S_3. We also obtain the Yang-Mills analogue of the Salam-Sezgin solution of the U(1) theory, namely R1,2×S3R^{1,2}\times S^3, where the S3S^3 is supported by a sphaleron. Finally we obtain the additional constraints implied by enhanced supersymmetry, and discuss Penrose limits in the theories.Comment: 1+29 pages, late

    Sub-Kolmogorov-Scale Fluctuations in Fluid Turbulence

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    We relate the intermittent fluctuations of velocity gradients in turbulence to a whole range of local dissipation scales generalizing the picture of a single mean dissipation length. The statistical distribution of these local dissipation scales as a function of Reynolds number is determined in numerical simulations of forced homogeneous isotropic turbulence with a spectral resolution never applied before which exceeds the standard one by at least a factor of eight. The core of the scale distribution agrees well with a theoretical prediction. Increasing Reynolds number causes the generation of ever finer local dissipation scales. This is in line with a less steep decay of the large-wavenumber energy spectra in the dissipation range. The energy spectrum for the highest accessible Taylor microscale Reynolds number R_lambda=107 does not show a bottleneck.Comment: 8 pages, 5 figures (Figs. 1 and 3 in reduced quality
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