3,162 research outputs found

    More Inequality, Less Social Mobility

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    We investigate the relationship between inequality and intergenerational mobility. Proxying fathers’ earnings with using detailed occupational data, we find that sons who grew up in countries that were more unequal in the 1970s were less likely to have experienced social mobility by the late-1990s.intergenerational mobility, income distribution, equality of opportunity

    Do Rising Top Incomes Lift All Boats?

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    Pooling data for 1905 to 2000, we find no systematic relationship between top income shares and economic growth in a panel of 12 developed nations observed for between 22 and 85 years. After 1960, however, a one percentage point rise in the top decile’s income share is associated with a statistically significant 0.12 point rise in GDP growth during the following year. This relationship is not driven by changes in either educational attainment or top tax rates. If the increase in inequality is permanent, the increase in growth appears to be permanent. However, our estimates imply that it would take 13 years for the cumulative positive effect of faster growth on the mean income of the bottom nine deciles to offset the negative effect of reducing their share of total income.inequality, growth, income distribution, national income

    Do Rising Top Incomes Lift All Boats?

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    Pooling data for 1905 to 2000, we find no systematic relationship between top income shares and economic growth in a panel of 12 developed nations observed for between 22 and 85 years. After 1960, however, a one percentage point rise in the top decile's income share is associated with a statistically significant 0.12 point rise in GDP growth during the following year. This relationship is not driven by changes in either educational attainment or top tax rates. If the increase in inequality is permanent, the increase in growth appears to be permanent. However, our estimates imply that it would take 13 years for the cumulative positive effect of faster growth on the mean income of the bottom nine deciles to offset the negative effect of reducing their share of total income.inequality, growth, income distribution, national income

    An Overview of the Volatiles Investigating Polar Exploration Rover (VIPER) Mission

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    A critical goal to both science and exploration is to understand the form and location of lunar polar volatiles. The lateral and vertical distributions of these volatiles inform us of the processes that control the emplacement and retention of these volatiles, as well as helping to formulate in-situ resource utilization (ISRU) architectures. While significant progress has been made from orbital observations, measurements at a range of scales from centimeters to kilometers across the lunar surface are needed to generate adequate "volatile mineral models" for use in evaluating the resource potential of volatiles at the Moon. VIPER is a solar and battery powered rover mission designed to operate over multiple lunar days, traversing several kilometers as it continuously monitors for subsurface hydrogen and other surface volatiles. In specific thermal terrain types, including permanently shadowed terrain and locales that permit near-surface ice stability, subsurface samples will be examined for volatile content using a one-meter drill. This talk will provide an overview of the VIPER mission which is scheduled for flight to the Lunar South Pole in December 2022

    Creation of vortices in a Bose-Einstein condensate by a Raman technique

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    We propose a method for taking a Bose-Einstein condensate in the ground trap state simultaneously to a different atomic hyperfine state and to a vortex trap state. This can be accomplished through a Raman scheme in which one of the two copropagating laser beams has a higher-order Laguerre-Gaussian mode profile. Coefficients relating the beam waist, pulse area, and trap potentials for a complete transfer to the m = 1 vortex are calculated for a condensate in the non-interacting and strongly interacting regimes.Comment: RevTex, 4 pages, 2 PostScript figure

    SN 2017ein and the Possible First Identification of a Type Ic Supernova Progenitor

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    We have identified a progenitor candidate in archival Hubble Space Telescope (HST) images for the Type Ic SN 2017ein in NGC 3938, pinpointing the candidate's location via HST Target-of-Opportunity imaging of the SN itself. This would be the first identification of a stellar-like object as a progenitor candidate for any Type Ic supernova to date. We also present observations of SN 2017ein during the first ~49 days since explosion. We find that SN 2017ein most resembles the well-studied Type Ic SN 2007gr. We infer that SN 2017ein experienced a total visual extinction of A_V~1.0--1.9 mag, predominantly because of dust within the host galaxy. Although the distance is not well known, if this object is the progenitor, it was likely of high initial mass, ~47--48 M_sun if a single star, or ~60--80 M_sun if in a binary system. However, we also find that the progenitor candidate could be a very blue and young compact cluster, further implying a very massive (>65 M_sun) progenitor. Furthermore, the actual progenitor might not be associated with the candidate at all and could be far less massive. From the immediate stellar environment, we find possible evidence for three different populations; if the SN progenitor was a member of the youngest population, this would be consistent with an initial mass of ~57 M_sun. After it has faded, the SN should be reobserved at high spatial resolution and sensitivity, to determine whether the candidate is indeed the progenitor.Comment: Revised, following referee's comments, and accepted to ApJ; 21 pages, 10 figure

    Salvage Fractionated Stereotactic Re-irradiation (FSRT) for Patients with Recurrent High Grade Gliomas Progressed after Bevacizumab Treatment

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    Purpose/Objectives: Bevacizumab failure is a major clinical problem in the manage- ment of high grade gliomas (HGG), with a median overall survival of less than 4 months (m). This study evaluated the efficacy of fractionated stereotactic re-irradiation (FSRT) for patients with HGG after progression on Bevacizumab. Materials/Methods: Retrospective review was conducted of patients treated with FSRT after progression on bevacizumab. A total of 36 patients were identified. FSRT was most commonly delivered in 3.5 Gy fractions to a total dose of 35 Gy. Survival from initial diagnosis, as well as from recurrence and re-irradiation, were utilized as study endpoints. Univariate and multivariate analysis was performed. Results: Among the 36 patients, 31 patients had recurrent glioblastoma, and 5 patients had recurrent anaplastic astrocytoma. The median time from initial bevacizumab treatment to FSRT was 8.5 m (range 2.3 – 32.0 m). The median plan target volume for FSRT was 27.5 cc (range 1.95 – 165 cc). With a median follow up of 20.4 m, the overall survival of the patients since initial diagnosis was also 24.9 m. The median overall survival after initiation of bevacizumab was 13.4 months. The median overall survival from FSRT was 4.8 m. FSRT treatment was well tolerated with no Grade \u3e3 toxicity. Conclusions: Favorable outcomes were observed in patients with recurrent HGG who received salvage FSRT after bevacizumab failure. The treatment was well tolerated. Prospective study is warranted to further evaluate the efficacy of salvage FSRT for selected patients with recurrent HGG amenable to FSRT, who had failed bevacizumab treatment

    Reconstruction of the joint state of a two-mode Bose-Einstein condensate

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    We propose a scheme to reconstruct the state of a two-mode Bose-Einstein condensate, with a given total number of atoms, using an atom interferometer that requires beam splitter, phase shift and non-ideal atom counting operations. The density matrix in the number-state basis can be computed directly from the probabilities of different counts for various phase shifts between the original modes, unless the beamsplitter is exactly balanced. Simulated noisy data from a two-mode coherent state is produced and the state is reconstructed, for 49 atoms. The error can be estimated from the singular values of the transformation matrix between state and probability data.Comment: 4 pages (REVTeX), 5 figures (PostScript

    Non-destructive optical measurement of relative phase between two Bose condensates

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    We study the interaction of light with two Bose condensates as an open quantum system. The two overlapping condensates occupy two different Zeeman sublevels and two driving light beams induce a coherent quantum tunneling between the condensates. We derive the master equation for the system. It is shown that stochastic simulations of the measurements of spontaneously scattered photons establish the relative phase between two Bose condensates, even though the condensates are initially in pure number states. These measurements are non-destructive for the condensates, because only light is scattered, but no atoms are removed from the system. Due to the macroscopic quantum interference the detection rate of photons depends substantially on the relative phase between the condensates. This may provide a way to distinguish, whether the condensates are initially in number states or in coherent states.Comment: 26 pages, RevTex, 8 postscript figures, 1 MacBinary eps-figur
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