1,408 research outputs found

    Chronic bee paralysis as a serious emerging threat to honey bees

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    This work was funded jointly by BBSRC grants BB/R00482X/1 (Newcastle University) and BB/R00305X/1 (University of St Andrews) in partnership with The Bee Farmers’ Association and the National Bee Unit of the Animal and Plant Health Agency.Chronic bee paralysis is a well-defined viral disease of honey bees with a global distribution that until recently caused rare but severe symptomatology including colony loss. Anecdotal evidence indicates a recent increase in virus incidence in several countries, but no mention of concomitant disease. We use government honey bee health inspection records from England and Wales to test whether chronic bee paralysis is an emerging infectious disease and investigate the spatiotemporal patterns of disease. The number of chronic bee paralysis cases increased exponentially between 2007 and 2017, demonstrating chronic bee paralysis as an emergent disease. Disease is highly clustered spatially within most years, suggesting local spread, but not between years, suggesting disease burnt out with periodic reintroduction. Apiary and county level risk factors are confirmed to include scale of beekeeping operation and the history of honey bee imports. Our findings offer epidemiological insight into this damaging emerging disease.Publisher PDFPeer reviewe

    Galaxy Clusters Selected with the Sunyaev-Zel'dovich Effect from 2008 South Pole Telescope Observations

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    We present a detection-significance-limited catalog of 21 Sunyaev-Zel'dovich selected galaxy clusters. These clusters, along with 1 unconfirmed candidate, were identified in 178 deg^2 of sky surveyed in 2008 by the South Pole Telescope to a depth of 18 uK-arcmin at 150 GHz. Optical imaging from the Blanco Cosmology Survey (BCS) and Magellan telescopes provided photometric (and in some cases spectroscopic) redshift estimates, with catalog redshifts ranging from z=0.15 to z>1, with a median z = 0.74. Of the 21 confirmed galaxy clusters, three were previously identified as Abell clusters, three were presented as SPT discoveries in Staniszewski et al, 2009, and three were first identified in a recent analysis of BCS data by Menanteau et al, 2010; the remaining 12 clusters are presented for the first time in this work. Simulated observations of the SPT fields predict the sample to be nearly 100% complete above a mass threshold of M_200 ~ 5x10^14 M_sun/h at z = 0.6. This completeness threshold pushes to lower mass with increasing redshift, dropping to ~4x10^14 M_sun/h at z=1. The size and redshift distribution of this catalog are in good agreement with expectations based on our current understanding of galaxy clusters and cosmology. In combination with other cosmological probes, we use the cluster catalog to improve estimates of cosmological parameters. Assuming a standard spatially flat wCDM cosmological model, the addition of our catalog to the WMAP 7-year analysis yields sigma_8 = 0.81 +- 0.09 and w = -1.07 +- 0.29, a ~50% improvement in precision on both parameters over WMAP7 alone.Comment: 19 pages, 9 figures, 4 appendice

    The Halo Mass of Optically Luminous Quasars at z ,F≈ ,F1-2 Measured via Gravitational Deflection of the Cosmic Microwave Background

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    © 2019. The American Astronomical Society. All rights reserved.We measure the average deflection of cosmic microwave background photons by quasars at 〈Z〉= 1.7. Our sample is selected from the Sloan Digital Sky Survey to cover the redshift range 0.9 ≤z≤2.2 with absolute i-band magnitudes of M i ≤-24 (K-corrected to z = 2). A stack of nearly 200,000 targets reveals an 8δ detection of Planck's estimate of the lensing convergence toward the quasars. We fit the signal with a model comprising a Navarro-Frenk-White density profile and a two-halo term accounting for correlated large-scale structure, which dominates the observed signal. The best-fitting model is described by an average halo mass log 10 (M h h -1 M)12.6 ±0.2 = and linear bias b=2.7±0.3 at 〈Z 〉= 1.7, in excellent agreement with clustering studies. We also report a hint, at a 90% confidence level, of a correlation between the convergence amplitude and luminosity, indicating that quasars brighter than Mi≲ -26 reside in halos of typical mass M h ≈ 10 13 h -1 M, scaling roughly as M h ∞ L opt 3/4 at M i ≲-24 mag, in good agreement with physically motivated quasar demography models. Although we acknowledge that this luminosity dependence is a marginal result, the observed Mh-L opt relationship could be interpreted as a reflection of the cutoff in the distribution of black hole accretion rates toward high Eddington ratios: the weak trend of Mh with Lopt observed at low luminosity becomes stronger for the most powerful quasars, which tend to be accreting close to the Eddington limit.Peer reviewedFinal Accepted Versio

    Absence of a strong, deep-reaching Antarctic Circumpolar Current zonal flow across the Tasmanian gateway during the Oligocene to early Miocene

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    The vigorous eastward flow of the Antarctic Circumpolar Current (ACC) connects all major ocean basins and plays a prominent role in the transport of heat, carbon and nutrients around the globe. However, the establishment of a deep circumpolar flow, similar to the present-day ACC, remains controversial thereby obscuring our understanding of its climatic impact. Deciphering the chemical composition of Circumpolar Deep Water (CDW) within the ACC can provide critical insights about its development and evolution. Here we present new fossil fish teeth/bone debris neodymium isotope (ε) records from Deep Sea Drilling Project (DSDP) Sites 278 and 274 in the southwest Pacific Ocean, with the aim to trace changes in deep water masses across the Tasmanian Gateway between the early Oligocene and early Miocene (~ 33–22 Ma). Site 274 provides the first Nd isotope record proximal to the Ross Sea during the Oligocene (33.5–23.4 Ma). Its Nd isotope composition shows excursions to very radiogenic values, ε = −3.1 and ε − 3.7, at 33.5 Ma and 23.8 Ma, respectively, in response to major steps in Antarctic ice sheet expansion. A shift to lower, more unradiogenic ε values between 29.7 and 29.1 Ma is linked to an increased influence of proto-CDW upwelling at the site. In contrast, the Nd isotope record from Site 278 in the southern Emerald Basin shows little variability (ε = −6.0 to −6.7) throughout the Oligocene and early Miocene (30.9–21.8 Ma). Comparison with published data north of the ACC path, demonstrates the presence of two deep water masses in the South Pacific prior to the inferred onset of the ACC (33–30 Ma), one occupying depths between ~2500 and 3000 m (ε ~ −3 to −5) and a deep/bottom water mass (> 3000 m) with a more unradiogenic Nd isotope composition (ε ~ −6). Site 278 located close to the proto-polar front (proto-PF) indicates that following the inferred onset of the ACC, deep waters bathing the southern Emerald Basin remained more radiogenic in the Southwest Pacific compared to sites along the proto-PF in the South Atlantic and Indian Ocean (ε ~ −8.1). This indicates a provinciality in Nd isotope compositions of deep waters along the proto-PF across the Tasmanian Gateway. Our data are incompatible with the existence of a modern-like homogenous (lateral and vertical) Nd isotope composition of CDW along the main flow path of the ACC in all oceanic basins in the Oligocene to early Miocene. We attribute distinct Nd isotope compositions of deep waters across the Tasmanian Gateway to reflect a less deep reaching and weaker ACC (proto-ACC) than today. Our findings suggest that the modern strong and deep-reaching ACC flow must have been developed at a later point in the Neogene.Funding to this research is provided by the Alexander S. Onassis Public Benefit Foundation Ph.D. research grant: F ZL 016-1/2015-2016; the Spanish Ministry of Economy, Industry and Competitivity (grants CTM2017-89711-C2-1/2-P), co-funded by the European Union through FEDER funds; and an ECORD Research grant awarded to DE. PKB and FH acknowledge funding through the European Research Council starting grant #802835 OceaNice and NWO polar programme grant ALWPP2016.001. This paper is a contribution to the SCAR PAIS Programme

    A Measurement of the Cosmic Microwave Background Damping Tail from the 2500-square-degree SPT-SZ survey

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    We present a measurement of the cosmic microwave background (CMB) temperature power spectrum using data from the recently completed South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) survey. This measurement is made from observations of 2540 deg2^2 of sky with arcminute resolution at 150 150\,GHz, and improves upon previous measurements using the SPT by tripling the sky area. We report CMB temperature anisotropy power over the multipole range 650<ℓ<3000650<\ell<3000. We fit the SPT bandpowers, combined with the seven-year Wilkinson Microwave Anisotropy Probe (WMAP7) data, with a six-parameter LCDM cosmological model and find that the two datasets are consistent and well fit by the model. Adding SPT measurements significantly improves LCDM parameter constraints; in particular, the constraint on θs\theta_s tightens by a factor of 2.7. The impact of gravitational lensing is detected at 8.1 σ8.1\, \sigma, the most significant detection to date. This sensitivity of the SPT+WMAP7 data to lensing by large-scale structure at low redshifts allows us to constrain the mean curvature of the observable universe with CMB data alone to be Ωk=−0.003−0.018+0.014\Omega_k=-0.003^{+0.014}_{-0.018}. Using the SPT+WMAP7 data, we measure the spectral index of scalar fluctuations to be ns=0.9623±0.0097n_s=0.9623 \pm 0.0097 in the LCDM model, a 3.9 σ3.9\,\sigma preference for a scale-dependent spectrum with ns<1n_s<1. The SPT measurement of the CMB damping tail helps break the degeneracy that exists between the tensor-to-scalar ratio rr and nsn_s in large-scale CMB measurements, leading to an upper limit of r<0.18r<0.18 (95%,C.L.) in the LCDM+rr model. Adding low-redshift measurements of the Hubble constant (H0H_0) and the baryon acoustic oscillation (BAO) feature to the SPT+WMAP7 data leads to further improvements. The combination of SPT+WMAP7+H0H_0+BAO constrains ns=0.9538±0.0081n_s=0.9538 \pm 0.0081 in the LCDM model, a 5.7 σ5.7\,\sigma detection of ns<1n_s < 1, ... [abridged]Comment: 21 pages, 10 figures. Replaced with version accepted by ApJ. Data products are available at http://pole.uchicago.edu/public/data/story12

    Consistency of cosmic microwave background temperature measurements in three frequency bands in the 2500-square-degree SPT-SZ survey

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    We present an internal consistency test of South Pole Telescope (SPT) measurements of the cosmic microwave background (CMB) temperature anisotropy using three-band data from the SPT-SZ survey. These measurements are made from observations of ~2500 deg^2 of sky in three frequency bands centered at 95, 150, and 220 GHz. We combine the information from these three bands into six semi-independent estimates of the CMB power spectrum (three single-frequency power spectra and three cross-frequency spectra) over the multipole range 650 < l < 3000. We subtract an estimate of foreground power from each power spectrum and evaluate the consistency among the resulting CMB-only spectra. We determine that the six foreground-cleaned power spectra are consistent with the null hypothesis, in which the six cleaned spectra contain only CMB power and noise. A fit of the data to this model results in a chi-squared value of 236.3 for 235 degrees of freedom, and the probability to exceed this chi-squared value is 46%.Comment: 21 pages, 4 figures, current version matches version published in JCA

    A Direct Measurement of the Linear Bias of Mid-infrared-selected Quasars at z ap 1 Using Cosmic Microwave Background Lensing

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    We measure the cross-power spectrum of the projected mass density as traced by the convergence of the cosmic microwave background lensing field from the South Pole Telescope (SPT) and a sample of Type 1 and 2 (unobscured and obscured) quasars at langzrang ~ 1 selected with the Wide-field Infrared Survey Explorer, over 2500 deg2. The cross-power spectrum is detected at ≈7σ, and we measure a linear bias b = 1.61 ± 0.22, consistent with clustering analyses. Using an independent lensing map, derived from Planck observations, to measure the cross-spectrum, we find excellent agreement with the SPT analysis. The bias of the combined sample of Type 1 and 2 quasars determined in this work is similar to that previously determined for Type 1 quasars alone; we conclude that obscured and unobscured quasars trace the matter field in a similar way. This result has implications for our understanding of quasar unification and evolution schemes.Peer reviewe

    A CMB lensing mass map and its correlation with the cosmic infrared background

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    We use a temperature map of the cosmic microwave background (CMB) obtained using the South Pole Telescope at 150 GHz to construct a map of the gravitational convergence to z ~ 1100, revealing the fluctuations in the projected mass density. This map shows individual features that are significant at the ~ 4 sigma level, providing the first image of CMB lensing convergence. We cross-correlate this map with Herschel/SPIRE maps covering 90 square degrees at wavelengths of 500, 350, and 250 microns. We show that these submillimeter-wavelength (submm) maps are strongly correlated with the lensing convergence map, with detection significances in each of the three submm bands ranging from 6.7 to 8.8 sigma. We fit the measurement of the cross power spectrum assuming a simple constant bias model and infer bias factors of b=1.3-1.8, with a statistical uncertainty of 15%, depending on the assumed model for the redshift distribution of the dusty galaxies that are contributing to the Herschel/SPIRE maps.Comment: 5 pages, 3 figures, to be submitted to ApJ
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