928 research outputs found

    Divided government and significant legislation: A History of Congress from 1789 to 2010

    Full text link
    This article presents and analyzes the most comprehensive database to date of significant acts of Congress—from 1789 to 2010—to test whether divided party control of government affects the number of important acts Congress passes. We find that unified control corresponds with one additional significant act passed per Congress in the nineteenth century and four additional such acts in the twentieth century. However, party control of government cannot explain the broad historical trends in the rate at which Congress passes significant legislation. Nixon in 1969 was far more successful with a Democratic Congress than was McKinley in 1897 with a Republican one

    Alveolar Macrophages Isolated Directly From Human Cytomegalovirus (HCMV)-Seropositive Individuals Are Sites of HCMV Reactivation In Vivo.

    Get PDF
    Human cytomegalovirus (HCMV) causes significant morbidity in the immunocompromised host. Following primary infection, the virus establishes latent infection in progenitor cells of the myeloid lineage. These cells exhibit limited viral gene transcription and no evidence of de novo virion production. It is well recognized that differentiation of latently infected myeloid progenitor cells to dendritic or macrophage-like cells permits viral reactivation in vitro. This has been used to support the concept that viral reactivation in HCMV carriers routinely occurs from such terminally differentiated myeloid cells in vivo. However, to date this has not been shown for in vivo-differentiated macrophages. This study is the first to demonstrate that alveolar macrophages from HCMV carriers express immediate early lytic genes and produce infectious virus. This supports the view, until now based on in vitro data, that terminally differentiated myeloid cells in vivo are sites of HCMV reactivation and potential centers of viral dissemination in latently infected individuals with no evidence of virus disease or dissemination.This work was supported by the UK Medical Research Council (grant 0701279 to J. S.) and the National Institute for Health Research UK Biomedical Research Centre (to J. S. and E. R. C.).This is the final published version. It first appeared at http://jid.oxfordjournals.org/content/211/12/1936

    Effects of antenatal betamethasone on preterm human and mouse ductus arteriosus: comparison with baboon data.

    Get PDF
    BackgroundAlthough studies involving preterm infants ≤34 weeks gestation report a decreased incidence of patent ductus arteriosus after antenatal betamethasone, studies involving younger gestation infants report conflicting results.MethodsWe used preterm baboons, mice, and humans (≤276/7 weeks gestation) to examine betamethasone's effects on ductus gene expression and constriction both in vitro and in vivo.ResultsIn mice, betamethasone increased the sensitivity of the premature ductus to the contractile effects of oxygen without altering the effects of other contractile or vasodilatory stimuli. Betamethasone's effects on oxygen sensitivity could be eliminated by inhibiting endogenous prostaglandin/nitric oxide signaling. In mice and baboons, betamethasone increased the expression of several developmentally regulated genes that mediate oxygen-induced constriction (K+ channels) and inhibit vasodilator signaling (phosphodiesterases). In human infants, betamethasone increased the rate of ductus constriction at all gestational ages. However, in infants born ≤256/7 weeks gestation, betamethasone's contractile effects were only apparent when prostaglandin signaling was inhibited, whereas at 26-27 weeks gestation, betamethasone's contractile effects were apparent even in the absence of prostaglandin inhibitors.ConclusionsWe speculate that betamethasone's contractile effects may be mediated through genes that are developmentally regulated. This could explain why betamethasone's effects vary according to the infant's developmental age at birth

    Visualizing sound emission of elephant vocalizations: evidence for two rumble production types

    Get PDF
    Recent comparative data reveal that formant frequencies are cues to body size in animals, due to a close relationship between formant frequency spacing, vocal tract length and overall body size. Accordingly, intriguing morphological adaptations to elongate the vocal tract in order to lower formants occur in several species, with the size exaggeration hypothesis being proposed to justify most of these observations. While the elephant trunk is strongly implicated to account for the low formants of elephant rumbles, it is unknown whether elephants emit these vocalizations exclusively through the trunk, or whether the mouth is also involved in rumble production. In this study we used a sound visualization method (an acoustic camera) to record rumbles of five captive African elephants during spatial separation and subsequent bonding situations. Our results showed that the female elephants in our analysis produced two distinct types of rumble vocalizations based on vocal path differences: a nasally- and an orally-emitted rumble. Interestingly, nasal rumbles predominated during contact calling, whereas oral rumbles were mainly produced in bonding situations. In addition, nasal and oral rumbles varied considerably in their acoustic structure. In particular, the values of the first two formants reflected the estimated lengths of the vocal paths, corresponding to a vocal tract length of around 2 meters for nasal, and around 0.7 meters for oral rumbles. These results suggest that African elephants may be switching vocal paths to actively vary vocal tract length (with considerable variation in formants) according to context, and call for further research investigating the function of formant modulation in elephant vocalizations. Furthermore, by confirming the use of the elephant trunk in long distance rumble production, our findings provide an explanation for the extremely low formants in these calls, and may also indicate that formant lowering functions to increase call propagation distances in this species'

    Writing in Britain and Ireland, c. 400 to c. 800

    Get PDF
    No abstract available

    The WiggleZ Dark Energy Survey: Direct constraints on blue galaxy intrinsic alignments at intermediate redshifts

    Get PDF
    Correlations between the intrinsic shapes of galaxy pairs, and between the intrinsic shapes of galaxies and the large-scale density field, may be induced by tidal fields. These correlations, which have been detected at low redshifts (z<0.35) for bright red galaxies in the Sloan Digital Sky Survey (SDSS), and for which upper limits exist for blue galaxies at z~0.1, provide a window into galaxy formation and evolution, and are also an important contaminant for current and future weak lensing surveys. Measurements of these alignments at intermediate redshifts (z~0.6) that are more relevant for cosmic shear observations are very important for understanding the origin and redshift evolution of these alignments, and for minimising their impact on weak lensing measurements. We present the first such intermediate-redshift measurement for blue galaxies, using galaxy shape measurements from SDSS and spectroscopic redshifts from the WiggleZ Dark Energy Survey. Our null detection allows us to place upper limits on the contamination of weak lensing measurements by blue galaxy intrinsic alignments that, for the first time, do not require significant model-dependent extrapolation from the z~0.1 SDSS observations. Also, combining the SDSS and WiggleZ constraints gives us a long redshift baseline with which to constrain intrinsic alignment models and contamination of the cosmic shear power spectrum. Assuming that the alignments can be explained by linear alignment with the smoothed local density field, we find that a measurement of \sigma_8 in a blue-galaxy dominated, CFHTLS-like survey would be contaminated by at most +/-0.02 (95% confidence level, SDSS and WiggleZ) or +/-0.03 (WiggleZ alone) due to intrinsic alignments. [Abridged]Comment: 18 pages, 12 figures, accepted to MNRAS; v2 has correction to one author's name, NO other changes; v3 has minor changes in explanation and calculations, no significant difference in results or conclusions; v4 has an additional footnote about model interpretation, no changes to data/calculations/result

    An Initial Study of Multimodality in Wind Farm Layout Optimization Problems

    Get PDF
    A study into the phenomena of multimodality in wind farm layout optimisation problems is presented. Little previous work has studied multimodality so this work aims to begin providing quantifiable results on multimodality in farm layout optimisation. The problems of optimising the location of a four and nine turbine farm within a bound circular domain are considered. Multi-start gradient-based optimisation is used to determine optima present in each case. Clear multimodality was found in all cases tested. With increasing farm size, the number of optima present increases, however the difference in performance of those optima is small. Therefore, while multimodality is present, for large farms, the chance of locating a local minima that has a detrimental performance compared to the global optimum, is small

    Heterogeneous Nucleation in the Low Barrier Regime

    Full text link
    In simulations of the 2D Ising model, we examine heterogeneous nucleation induced by a small impurity consisting of a line of ll fixed spins. As ll increases, we identify a limit of stability beyond which the metastable phase is not defined. We evaluate the free energy barrier for nucleation of the stable phase, and show that contrary to expectation, the barrier does not vanish on approach to the limit of stability. We also demonstrate that our values for the height of the barrier yield predictions for the nucleation time (from transition state theory) and the size of the critical cluster (from the nucleation theorem) that are in excellent agreement with direct measurements, even near the limit of stability.Comment: 7 pages, 6 figures; to appear in Phys. Rev.

    Senior Recital: Joseph Poole, bass trombone

    Get PDF
    This recital is presented in partial fulfillment of requirements for the degree Bachelor of Music in Performance. Mr. Poole studies bass trombone with Brian Hecht.https://digitalcommons.kennesaw.edu/musicprograms/1245/thumbnail.jp

    Measuring the hydraulic functionality of PPP-managed water supply infrastructure in Madagascar

    Get PDF
    This paper presents results from an on-going study that is aimed at developing continuous, objective tools for evaluating the performance of water system functionality. An additional goal of this study is to explore external factors that influence sustainability in order to better understand the effectiveness of PPP managed water systems. Pressure transducers were installed in water system storage tanks to continuously measure water levels and allow determination of supply/demand flows, and functionality in terms of water delivery was assessed using tank level thresholds and service provision levels of access. Both systems studied exhibited high functionality despite different contextual factors, and metered data was used to verify consumption estimates. The objective of this paper is to demonstrate the use of monitoring tools such as this to better inform planning, needed to achieve universal access
    corecore