3,061 research outputs found

    When Inequality is Equitable: Validity, Propriety and Third Party Allocations

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    The author summarizes theories of equity and distributive justice that predict actors use legitimate distribution rules to act to maintain or to restore equity. He elaborates those ideas, distinguishing legitimacy based on validity (socially supported) from propriety (acceptance by the focal actor). Experimental research showed strong effects of both types of legitimacy on behavior, with validity having slightly stronger effects.This research was supported by a grant from the National Science Foundation (SOC #7817^3<»), Morris Zelditch, Jr.» Principal Investigator. Computations were supported by a grant from the Office of the Dean of Graduate Studies and Research at Stanford University

    Making the Case for Diversity in Philanthropy

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    While many foundations have long sought to become more inclusive as a logical extension of their missions, the business case for incorporating diversity has renewed interest in understanding how diversity can also enhance the effectiveness of philanthropic organizations. Because prior movements to increase diversity in philanthropy have focused on moral, rather than operational, arguments and because the field lacks an easy way to measure outcomes, strong evaluation measures of diversity's impacts on philanthropic activity have not been developed. Numerous studies from the corporate sphere, however, suggest that greater inclusiveness may improve an organization's processes and outcomes. Many philanthropic experts and practitioners believe that these gains may apply to grantmaking institutions as well as businesses.

    Legitimation, Endorsement, and Compliance

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    The theoretical development distinguishes three objects of legitimation, of persons, of positions, and of actions; and three types of legitimacy, propriety, endorsement, and authorization. Propriety is normative support of power, endorsement is group support, and authorization is support of an actor higher in the organizational structure. They conducted an experiment varying levels of endorsement. Results showed strong effects of endorsement on compliance. Related publications include Walker et al. (1986), Ridgeway et al. (1994), and Younts (2008)

    MOST detects variability on tau Bootis possibly induced by its planetary companion

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    (abridged) There is considerable interest in the possible interaction between parent stars and giant planetary companions in 51 Peg-type systems. We demonstrate from MOST satellite photometry and Ca II K line emission that there has been a persistent, variable region on the surface of tau Boo A which tracked its giant planetary companion for some 440 planetary revolutions and lies ~68deg (phi=0.8) in advance of the sub-planetary point. The light curves are folded on a range of periods centered on the planetary orbital period and phase dependent variability is quantified by Fourier methods and by the mean absolute deviation (MAD) of the folded data for both the photometry and the Ca II K line reversals. The region varies in brightness on the time scale of a rotation by ~1 mmag. In 2004 it resembled a dark spot of variable depth, while in 2005 it varied between bright and dark. Over the 123 planetary orbits spanned by the photometry the variable region detected in 2004 and in 2005 are synchronised to the planetary orbital period within 0.0015 d. The Ca II K line in 2001, 2002 and 2003 also shows enhanced K-line variability centered on phi=0.8, extending coverage to some 440 planetary revolutions. The apparently constant rotation period of the variable region and its rapid variation make an explanation in terms of conventional star spots unlikely. The lack of complementary variability at phi=0.3 and the detection of the variable region so far in advance of the sub-planetary point excludes tidal excitation, but the combined photometric and Ca II K line reversal results make a good case for an active region induced magnetically on the surface of tau Boo A by its planetary companion.Comment: 7 pages, 7 figures; accepted for publication in A&

    Hot Jupiters and stellar magnetic activity

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    Recent observations suggest that stellar magnetic activity may be influenced by the presence of a close-by giant planet. Specifically, chromospheric hot spots rotating in phase with the planet orbital motion have been observed during some seasons in a few stars harbouring hot Jupiters. The spot leads the subplanetary point by a typical amount of about 60-70 degrees, with the extreme case of upsilon And where the angle is about 170 degrees. The interaction between the star and the planet is described considering the reconnection between the stellar coronal field and the magnetic field of the planet. Reconnection events produce energetic particles that moving along magnetic field lines impact onto the stellar chromosphere giving rise to a localized hot spot. A simple magnetohydrostatic model is introduced to describe the coronal magnetic field of the star connecting its surface to the orbiting planet. The field is assumed to be axisymmetric around the rotation axis of the star and its configuration is more general than a linear force-free field. With a suitable choice of the free parameters, the model can explain the phase differences between the hot spots and the planets observed in HD 179949, upsilon And, HD 189733, and tau Bootis, as well as their visibility modulation on the orbital period and seasonal time scales. The possible presence of cool spots associated with the planets in tau Boo and HD 192263 cannot be explained by the present model. However, we speculate about the possibility that reconnection events in the corona may influence subphotospheric dynamo action in those stars producing localized photospheric (and chromospheric) activity migrating in phase with their planets.Comment: 9 pages, 5 figures, 2 tables, 2 appendixes, accepted by Astronomy & Astrophysic

    Rotation periods of exoplanet host stars

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    The stellar rotation periods of ten exoplanet host stars have been determined using newly analysed Ca II H & K flux records from Mount Wilson Observatory and Stromgren b, y photometric measurements from Tennessee State University's automatic photometric telescopes (APTs) at Fairborn Observatory. Five of the rotation periods have not previously been reported, with that of HD 130322 very strongly detected at Prot = 26.1 \pm 3.5 d. The rotation periods of five other stars have been updated using new data. We use the rotation periods to derive the line-of-sight inclinations of the stellar rotation axes, which may be used to probe theories of planet formation and evolution when combined with the planetary orbital inclination found from other methods. Finally, we estimate the masses of fourteen exoplanets under the assumption that the stellar rotation axis is aligned with the orbital axis. We calculate the mass of HD 92788 b (28 MJ) to be within the low-mass brown dwarf regime and suggest that this object warrants further investigation to confirm its true nature.Comment: Accepted for publication in MNRAS. 15 pages, 11 figure

    Gender or Status: The Effects of Differences in Sex on Behavior under Certain Conditions of Disadvantage

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    Morris Zelditch Jr., Principal Investigatora. The authors address gender stereotypes: women are passive, dependent, compliant, cooperative, and socially oriented; while men are independent, competitive, and task-focused. They note that those behaviors are found in mixed-gender interaction, but are seldom found in same-gender groups. An experiment using a Bavelas box to collect messages tested ideas on effects of structure, legitimation, and rewards on behavior. Results showed no differences in the ways men and women acted in the experiment, which is consistent with a structural interpretation and not with a gender-difference interpretation.The research reported here was supported by dissertation year awards from the National Fellowships Fund and the Graduate Program Office at Stanford to the first author and by NSF Grant SOC 78-17434

    An accurate calculation of the nucleon axial charge with lattice QCD

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    We report on a lattice QCD calculation of the nucleon axial charge, gAg_A, using M\"{o}bius Domain-Wall fermions solved on the dynamical Nf=2+1+1N_f=2+1+1 HISQ ensembles after they are smeared using the gradient-flow algorithm. The calculation is performed with three pion masses, mπ∼{310,220,130}m_\pi\sim\{310,220,130\} MeV. Three lattice spacings (a∼{0.15,0.12,0.09}a\sim\{0.15,0.12,0.09\} fm) are used with the heaviest pion mass, while the coarsest two spacings are used on the middle pion mass and only the coarsest spacing is used with the near physical pion mass. On the mπ∼220m_\pi\sim220 MeV, a∼0.12a\sim0.12 fm point, a dedicated volume study is performed with mπL∼{3.22,4.29,5.36}m_\pi L \sim \{3.22,4.29,5.36\}. Using a new strategy motivated by the Feynman-Hellmann Theorem, we achieve a precise determination of gAg_A with relatively low statistics, and demonstrable control over the excited state, continuum, infinite volume and chiral extrapolation systematic uncertainties, the latter of which remains the dominant uncertainty. Our final determination at 2.6\% total uncertainty is gA=1.278(21)(26)g_A = 1.278(21)(26), with the first uncertainty including statistical and systematic uncertainties from fitting and the second including model selection systematics related to the chiral and continuum extrapolation. The largest reduction of the second uncertainty will come from a greater number of pion mass points as well as more precise lattice QCD results near the physical pion mass.Comment: 17 pages + 11 pages of references and appendices. 15 figures. Interested readers can download the Python analysis scripts and an hdf5 data file at https://github.com/callat-qcd/project_gA_v

    Baryogenesis through Collapsing String Loops in Gauged Baryon and Lepton Models

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    A scenario for the generation of the baryon asymmetry in the early Universe is proposed in which cosmic string loops, predicted by theories where the baryon and/or lepton numbers are gauged symmetries, collapse during the friction dominated period of string evolution. This provides a mechanism for the departure from thermal equilibrium necessary to have a nonvanishing baryon asymmetry. Examples of models are given where this idea can be implemented. In particular, the model with the gauge symmetry SU(3)c⊗SU(2)L⊗U(1)Y⊗U(1)B⊗U(1)LSU(3)_{c}\otimes SU(2)_{L}\otimes U(1)_{Y}\otimes U(1)_{B} \otimes U(1)_{L} has the interesting feature where sphaleron processes do not violate the baryon and lepton numbers so that no wash out of any initial baryon asymmetry occurs at the electroweak scale.Comment: 21 pages, LaTeX, PURD-TH-93-09, SISSA 87/93/
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