125 research outputs found

    Observational Consequences of Hydrodynamic Flows on Hot Jupiters

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    We use a grid-based shallow water model to simulate the atmospheric dynamics of the transiting hot Jupiter HD 209458b. Under the usual assumption that the planet is in synchronous rotation with zero obliquity, a steady state is reached with a well-localized cold spot centered 76 degrees east of the antistellar point. This represents a departure from predictions made by previous simulations in the literature that used the shallow water formalism; we find that the disagreement is explained by the factor of 30 shorter radiative timescale used in our model. We also examine the case that the planet is in Cassini state 2, in which the expected obliquity is ~90 degrees. Under these circumstances, a periodic equilibrium is reached, with the temperature slightly leading the solar forcing. Using these temperature distributions, we calculate disk-integrated bolometric infrared light curves from the planet. The light curves for the two models are surprisingly similar, despite large differences in temperature patterns in the two cases. In the zero-obliquity case, the intensity at the minimum is 66% of the maximum intensity, with the minimum occuring 72 degrees ahead of transit. In the high-obliquity case, the minimum occurs 54 degrees ahead of transit, with an intensity of 58% of the maximum.Comment: To be published in ApJ 657, L11

    Freedom of Religion and Eternal Accountability: Internal Auditing and its Implications within the Seventh-day Adventist Church

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    Based on archival resources, this study examines how accountability and internal auditing practices emerged and evolved within the distinctive setting of the Seventh-Day Adventist Church. Traditionally, this organisation was reluctant to account to its constituents in conventional financial terms. The Church administration prioritised notions of righteous accountability, while the general members of the church were concerned primarily with their own eternal accountability. That is, and reflecting its religious character, an emphasis on accountability relationships at a higher plane permeated the organisation: the Church with carrying out the mission it believed it had been entrusted with, and individual members with their own religious salvation. However, reservations over a perceived lack of monetary stewardship subsequently came to the fore. This precipitated an increased emphasis on financial accountability, with the adoption of an internal auditing function identified as a key outcome of this change

    The impact of subsidies on microfinance

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    In the next ten years, society will spend $20 billion U.S. on Microfinance Institutions (MFIs). Previous research on the impact of subsidies suggests that there is little if any consensus on an effective method to measure the impact of subsidies with considerable doubt existing that a financial variable is the most appropriate method. Findings suggest that in order for the impact of subsidies to be fully reconciled, some consideration must be given to the initial objectives and underlying motives of Microfinance Institutions (MFIs) and subsidy providers as this has an intrinsic bearing on any result they are attempting to achieve. I have attempted to shed light on a significant failure of the microfinance movement to date, in that we still have not clearly articulated by what qualitative measure we are to determine the success of MFI’s. Identifying what is the priority issue, even if it is a combination of factors requires willingness on behalf of both pro and anti- subsidy lobbies to concede that their approach may not be the most important. In order to transcend this discord a retrospective approach is taken to the impact of subsidies, whereby they are analysed from an initial substantive view in regard to underlying motive. I use this framework to assess microfinance in general and then apply my findings to a policy framework for microfinance institutions (MFIs) and subsidy providers.E

    The Cost Of Privacy: Riley v. California’s Impact on Cell Phone Searches

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    Riley v. California is the United States Supreme Court’s first attempt to regulate the searches of cell phones by law enforcement. The 2014 unanimous decision requires a warrant for all cell phone searches incident to arrest absent an emergency. This work summarizes the legal precedent and analyzes the limitations and practical implications of the ruling. General guidelines for members of the criminal justice system at all levels consistent with the Supreme Court’s decision are provided

    100 years of annual reporting by Australian Red Cross : Accountability amidst wars, disasters and loss of life

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    Purpose: This critical interpretive and historical case study of Australian Red Cross extends from the organisation’s beginning in 1914 through to the present day. The overarching purpose is to reveal and analyse the annual reporting practices of one of Australia’s oldest and most important humanitarian organisations in the discharge of accountability over the course of a century. Design/methodology/approach: A Political Economy of Accounting theoretical framework guides the content analysis and interpretation of findings. Background: While the review of literature acknowledges the annual report as a crucial element in the discharge of accountability, studies investigating the evolution of annual reports of International nongovernmental development and humanitarian aid organisations (INGDHOs) over extended periods of time appear to be absent from the literature. Findings: The annual reports were found to be responsive to the changing social, political, economic and institutional environment, casting doubt on any claims to objectivity in organisational management’s disclosures, including assertions regarding unadulterated adherence to its Fundamental Principles. Furthermore, sources of pressure from the wider environmental context impacted upon the development of accountability regimes and shaped the way in which organisational management reported to stakeholders. These regimes evidence the alignment of mission preservation and emotive disclosures with strategic priorities. Implications: This study extends understandings of how INGDHOs discharge accountability through annual reporting practices. It provides a more holistic framework for understanding the role of accountability in organisational management reporting, the development of accountability regimes and the implications for organisational and social functioning. Originality/value (significance): The contribution is distinctive not only for the context and extensive period covered, but also for the significant institutional setting of Australian Red Cross – encompassing deep social, political, economic and institutional changes. This adds to the extant literature and provides significant insights into the contested interplay between annual reporting practices and accountability regimes.Doctor of Philosoph

    Spitzer Secondary Eclipses of the Dense, Modestly-irradiated, Giant Exoplanet HAT-P-20b Using Pixel-Level Decorrelation

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    HAT-P-20b is a giant exoplanet that orbits a metal-rich star. The planet itself has a high total density, suggesting that it may also have a high metallicity in its atmosphere. We analyze two eclipses of the planet in each of the 3.6- and 4.5 micron bands of Warm Spitzer. These data exhibit intra-pixel detector sensitivity fluctuations that were resistant to traditional decorrelation methods. We have developed a simple, powerful, and radically different method to correct the intra-pixel effect for Warm Spitzer data, which we call pixel-level decorrelation (PLD). PLD corrects the intra-pixel effect very effectively, but without explicitly using - or even measuring - the fluctuations in the apparent position of the stellar image. We illustrate and validate PLD using synthetic and real data, and comparing the results to previous analyses. PLD can significantly reduce or eliminate red noise in Spitzer secondary eclipse photometry, even for eclipses that have proven to be intractable using other methods. Our successful PLD analysis of four HAT-P-20b eclipses shows a best-fit blackbody temperature of 1134 +/-29K, indicating inefficient longitudinal transfer of heat, but lacking evidence for strong molecular absorption. We find sufficient evidence for variability in the 4.5 micron band that the eclipses should be monitored at that wavelength by Spitzer, and this planet should be a high priority for JWST spectroscopy. All four eclipses occur about 35 minutes after orbital phase 0.5, indicating a slightly eccentric orbit. A joint fit of the eclipse and transit times with extant RV data yields e(cos{omega}) = 0.01352 (+0.00054, -0.00057), and establishes the small eccentricity of the orbit to high statistical confidence. Given the existence of a bound stellar companion, HAT-P-20b is another excellent candidate for orbital evolution via Kozai migration or other three-body mechanism.Comment: version published in ApJ, minor text and figure revision

    Constraints on the Atmospheric Circulation and Variability of the Eccentric Hot Jupiter XO-3b

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    We report secondary eclipse photometry of the hot Jupiter XO-3b in the 4.5~μ\mum band taken with the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. We measure individual eclipse depths and center of eclipse times for a total of twelve secondary eclipses. We fit these data simultaneously with two transits observed in the same band in order to obtain a global best-fit secondary eclipse depth of 0.1580±0.0036%0.1580\pm 0.0036\% and a center of eclipse phase of 0.67004±0.000130.67004\pm 0.00013 . We assess the relative magnitude of variations in the dayside brightness of the planet by measuring the size of the residuals during ingress and egress from fitting the combined eclipse light curve with a uniform disk model and place an upper limit of 0.05%\%. The new secondary eclipse observations extend the total baseline from one and a half years to nearly three years, allowing us to place an upper limit on the periastron precession rate of 2.9×10−32.9\times 10^{-3} degrees/day the tightest constraint to date on the periastron precession rate of a hot Jupiter. We use the new transit observations to calculate improved estimates for the system properties, including an updated orbital ephemeris. We also use the large number of secondary eclipses to obtain the most stringent limits to date on the orbit-to-orbit variability of an eccentric hot Jupiter and demonstrate the consistency of multiple-epoch Spitzer observations.Comment: 14 pages, 11 figures, published by Ap

    Direct Measure of Radiative and Dynamical Properties of an Exoplanet Atmosphere

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    Two decades after the discovery of 51 Peg b, the formation processes and atmospheres of short-period gas giants remain poorly understood. Observations of eccentric systems provide key insights on those topics as they can illuminate how a planet's atmosphere responds to changes in incident flux. We report here the analysis of multi-day multi-channel photometry of the eccentric (e ~ 0.93) hot Jupiter HD 80606 b obtained with the Spitzer Space Telescope. The planet's extreme eccentricity combined with the long coverage and exquisite precision of new periastron-passage observations allow us to break the degeneracy between the radiative and dynamical timescales of HD 80606 b's atmosphere and constrain its global thermal response. Our analysis reveals that the atmospheric layers probed heat rapidly (~4 hr radiative timescale) from <500 to 1400 K as they absorb ~ 20% of the incoming stellar flux during the periastron passage, while the planet's rotation period is 93_(-35)^(+85) hr, which exceeds the predicted pseudo-synchronous period (40 hr)
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