23,983 research outputs found

    Liturgy and Social Justice

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    (Excerpt) As a prelude to this vast subject, I would like to read a passage which is becoming part of my contemporary canon, a scene from Toni Morrison\u27s novel Beloved. She describes a worship service--though it is indeed quite different from most of our liturgies! This service is led by a holy woman named Baby Suggs. She is an elderly black woman, born into slavery and later bought into freedom by her son. Now, she lives in her own home on her own piece of ground near a little town in Ohio. Every Saturday, when warm weather came, Baby Suggs would gather the people--all of them former slaves--in the Clearing (with a capital C) ... In the heat of every Saturday afternoon, she sat in the Clearing while the people waited among the trees

    The application of quadratic optimal cooperative control synthesis to a CH-47 helicopter

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    A control-system design method, Quadratic Optimal Cooperative Control Synthesis (CCS), is applied to the design of a Stability and Control Augmentation Systems (SCAS). The CCS design method is different from other design methods in that it does not require detailed a priori design criteria, but instead relies on an explicit optimal pilot-model to create desired performance. The design model, which was developed previously for fixed-wing aircraft, is simplified and modified for application to a Boeing Vertol CH-47 helicopter. Two SCAS designs are developed using the CCS design methodology. The resulting CCS designs are then compared with designs obtained using classical/frequency-domain methods and Linear Quadratic Regulator (LQR) theory in a piloted fixed-base simulation. Results indicate that the CCS method, with slight modifications, can be used to produce controller designs which compare favorably with the frequency-domain approach

    Behavioural and physiological adaptations to low-temperature environments in the common frog, Rana temporaria

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    <b>Background</b><p></p> Extreme environments can impose strong ecological and evolutionary pressures at a local level. Ectotherms are particularly sensitive to low-temperature environments, which can result in a reduced activity period, slowed physiological processes and increased exposure to sub-zero temperatures. The aim of this study was to assess the behavioural and physiological responses that facilitate survival in low-temperature environments. In particular, we asked: 1) do high-altitude common frog (Rana temporaria) adults extend the time available for larval growth by breeding at lower temperatures than low-altitude individuals?; and 2) do tadpoles sampled from high-altitude sites differ physiologically from those from low-altitude sites, in terms of routine metabolic rate (RMR) and freeze tolerance? Breeding date was assessed as the first day of spawn observation and local temperature recorded for five, paired high- and low-altitude R. temporaria breeding sites in Scotland. Spawn was collected and tadpoles raised in a common laboratory environment, where RMR was measured as oxygen consumed using a closed respiratory tube system. Freeze tolerance was measured as survival following slow cooling to the point when all container water had frozen.<p></p> <b>Results</b><p></p> We found that breeding did not occur below 5°C at any site and there was no significant relationship between breeding temperature and altitude, leading to a delay in spawning of five days for every 100 m increase in altitude. The relationship between altitude and RMR varied by mountain but was lower for individuals sampled from high- than low-altitude sites within the three mountains with the highest high-altitude sites (≥900 m). In contrast, individuals sampled from low-altitudes survived freezing significantly better than those from high-altitudes, across all mountains.<p></p> <b>Conclusions</b><p></p> Our results suggest that adults at high-altitude do not show behavioural adaptations in terms of breeding at lower temperatures. However, tadpoles appear to have the potential to adapt physiologically to surviving at high-altitude via reduced RMR but without an increase in freeze tolerance. Therefore, survival at high-altitude may be facilitated by physiological mechanisms that permit faster growth rates, allowing completion of larval development within a shorter time period, alleviating the need for adaptations that extend the time available for larval growth

    Performance-related Funding of Universities – Does more Competition Lead to Grade Inflation?

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    German universities are regarded as being under-financed, inefficient, and performing below average if compared to universities in other European countries and the US. Starting in the 1990s, several German federal states implemented reforms to improve this situation. An important part of these reforms has been the introduction of indicator-based funding systems. These financing systems aimed at increasing the competition between universities by making their public funds dependent on their relative performance concerning different output measures, such as the share of students obtaining a degree or the amount of third party funds. This paper evaluates whether the indicator-based funding created unintended incentives, i.e. whether the reform caused a grade inflation. Estimating mean as well as quantile treatment effects, we cannot support the hypothesis that increased competition between universities causes grade inflation.Grade inflation; higher education funding; university competition

    Intraocular pressure in a cohort of healthy Eastern European schoolchildren: variations in method and corneal thickness

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    BACKGROUND: Intraocular pressure (IOP) in the developing eye of a child is not always easy to measure and there is no technique that is known to be the most accurate for the young eye. Measurements are needed on many cohorts of children with different tonometers to determine how the values correlate between instruments, whether corneal parameters affect readings and whether correlations between age and IOP values can be discerned. The aim of this study was to undertake a comparative analysis of three different tonometers on a group of healthy children to see whether differences exist and whether these may be related to central corneal thickness and/or radius of curvature. In addition, the study adds to the relatively small body of literature on IOP in the growing eye which will collectively allow trends to be identified and ultimately norms to be established. METHODS: IOP was measured on 115 eyes in a group of Polish children, aged between 5-17 years (mean±standard deviation [SD] 11.3±3.0 years) using three different tonometers: non-contact (NCT), the ICare and Goldmann applanation (GAT). Readings obtained were compared between instruments and with central corneal thickness and radius of curvature. RESULTS: The ICare tonometer provided statistically higher IOP values (16.9±3.4 mmHg) than the GAT (14.7±2.9 mmHg) regardless of corneal thickness and whether or not a correction factor was applied. A correlation was found between central corneal thickness (CCT) and IOP values obtained with all three tonometers but only the IOP values detected with the ICare tonometer showed a statistically significant correlation with radius of curvature (p<0.004). No correlations with age or gender were found for IOP values measured with any of the instruments. CONCLUSIONS: IOP measurements on children vary significantly between instruments and correlations are affected by the corneal thickness. Further studies on children are needed to determine which instrument is most appropriate and to derive a normative IOP scale for the growing eye

    For universals (but not finite-state learning) visit the zoo

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    Contralateral inhibition of click- and chirp-evoked human compound action potentials

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    Cochlear outer hair cells (OHC) receive direct efferent feedback from the caudal auditory brainstem via the medial olivocochlear (MOC) bundle. This circuit provides the neural substrate for the MOC reflex, which inhibits cochlear amplifier gain and is believed to play a role in listening in noise and protection from acoustic overexposure. The human MOC reflex has been studied extensively using otoacoustic emissions (OAE) paradigms; however, these measurements are insensitive to subsequent “downstream” efferent effects on the neural ensembles that mediate hearing. In this experiment, click- and chirp-evoked auditory nerve compound action potential (CAP) amplitudes were measured electrocochleographically from the human eardrum without and with MOC reflex activation elicited by contralateral broadband noise. We hypothesized that the chirp would be a more optimal stimulus for measuring neural MOC effects because it synchronizes excitation along the entire length of the basilar membrane and thus evokes a more robust CAP than a click at low to moderate stimulus levels. Chirps produced larger CAPs than clicks at all stimulus intensities (50–80 dB ppeSPL). MOC reflex inhibition of CAPs was larger for chirps than clicks at low stimulus levels when quantified both in terms of amplitude reduction and effective attenuation. Effective attenuation was larger for chirp- and click-evoked CAPs than for click-evoked OAEs measured from the same subjects. Our results suggest that the chirp is an optimal stimulus for evoking CAPs at low stimulus intensities and for assessing MOC reflex effects on the auditory nerve. Further, our work supports previous findings that MOC reflex effects at the level of the auditory nerve are underestimated by measures of OAE inhibition

    Security of quantum key distribution protocols using two-way classical communication or weak coherent pulses

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    We apply the techniques introduced in [Kraus et. al., Phys. Rev. Lett. 95, 080501, 2005] to prove security of quantum key distribution (QKD) schemes using two-way classical post-processing as well as QKD schemes based on weak coherent pulses instead of single-photon pulses. As a result, we obtain improved bounds on the secret-key rate of these schemes

    Medicaid in a Crunch: A Mid-FY 2009 Update on State Medicaid Issues in a Recession

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    Based on a November 2008 survey of Medicaid directors, examines the impact of the economic downturn on state Medicaid programs midway through fiscal year 2009, including possible cutbacks; the outlook for 2010; and priorities for federal action
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