We present optical light curves, redshifts, and classifications for spectroscopically confirmed Type Ia supernovae (SNe Ia) discovered by the Pan-STARRS1 (PS1) Medium Deep Survey. We detail ...improvements to the PS1 SN photometry, astrometry, and calibration that reduce the systematic uncertainties in the PS1 SN Ia distances. We combine the subset of PS1 SNe Ia (0.03 < z < 0.68) with useful distance estimates of SNe Ia from the Sloan Digital Sky Survey (SDSS), SNLS, and various low-z and Hubble Space Telescope samples to form the largest combined sample of SNe Ia, consisting of a total of SNe Ia in the range of 0.01 < z < 2.3, which we call the "Pantheon Sample." When combining Planck 2015 cosmic microwave background (CMB) measurements with the Pantheon SN sample, we find and for the wCDM model. When the SN and CMB constraints are combined with constraints from BAO and local H0 measurements, the analysis yields the most precise measurement of dark energy to date: and for the CDM model. Tension with a cosmological constant previously seen in an analysis of PS1 and low-z SNe has diminished after an increase of 2× in the statistics of the PS1 sample, improved calibration and photometry, and stricter light-curve quality cuts. We find that the systematic uncertainties in our measurements of dark energy are almost as large as the statistical uncertainties, primarily due to limitations of modeling the low-redshift sample. This must be addressed for future progress in using SNe Ia to measure dark energy.
Background/Objectives: Vegans, and to a lesser extent vegetarians, have low average circulating concentrations of vitamin B12; however, the relation between factors such as age or time on these diets ...and vitamin B12 concentrations is not clear. The objectives of this study were to investigate differences in serum vitamin B12 and folate concentrations between omnivores, vegetarians and vegans and to ascertain whether vitamin B12 concentrations differed by age and time on the diet. Subjects/Methods: A cross-sectional analysis involving 689 men (226 omnivores, 231 vegetarians and 232 vegans) from the European Prospective Investigation into Cancer and Nutrition Oxford cohort. Results: Mean serum vitamin B12 was highest among omnivores (281, 95% CI: 270–292 pmol/l), intermediate among vegetarians (182, 95% CI: 175–189 pmol/l) and lowest among vegans (122, 95% CI: 117–127 pmol/l). In all, 52% of vegans, 7% of vegetarians and one omnivore were classified as vitamin B12 deficient (defined as serum vitamin B12 <118 pmol/l). There was no significant association between age or duration of adherence to a vegetarian or a vegan diet and serum vitamin B12. In contrast, folate concentrations were highest among vegans, intermediate among vegetarians and lowest among omnivores, but only two men (both omnivores) were categorized as folate deficient (defined as serum folate <6.3 nmol/l). Conclusion: Vegans have lower vitamin B12 concentrations, but higher folate concentrations, than vegetarians and omnivores. Half of the vegans were categorized as vitamin B12 deficient and would be expected to have a higher risk of developing clinical symptoms related to vitamin B12 deficiency.
We present light curves and classification spectra of 17 hydrogen-poor superluminous supernovae (SLSNe) from the Pan-STARRS1 Medium Deep Survey (PS1 MDS). Our sample contains all objects from the PS1 ...MDS sample with spectroscopic classification that are similar to either of the prototypes SN 2005ap or SN 2007bi, without an explicit limit on luminosity. With a redshift range , PS1 MDS is the first SLSN sample primarily probing the high-redshift population; our multifilter PS1 light curves probe the rest-frame UV emission, and hence the peak of the spectral energy distribution. We measure the temperature evolution and construct bolometric light curves, and find peak luminosities of erg s−1 and lower limits on the total radiated energies of erg. The light curve shapes are diverse, with both rise and decline times spanning a factor of ∼5 and several examples of double-peaked light curves. When correcting for the flux-limited nature of our survey, we find a median peak luminosity at 4000 of and a spread of .
Here we present the results from a search within the Pan-STARRS1 Medium Deep Survey (PS1-MDS) for rapidly evolving and luminous transients. We identify 10 new transients with a time above ...half-maximum (t sub(1/2)) of less than 12 days and -16.5 > M > -20 mag. We find it difficult to reconcile the short timescale, high peak luminosity (L > 10 super(43) erg s super(-1)), and lack of UV line blanketing observed in many of these transients with an explosion powered mainly by the radioactive decay of super(56)Ni. Rather, we find that many are consistent with either (1) cooling envelope emission from the explosion of a star with a low-mass extended envelope that ejected very little (<0.03 M sub(middot in circle)) radioactive material, or (2) a shock breakout within a dense, optically thick, wind surrounding the progenitor star.
Clostridium difficile is recognized as an important cause of nosocomial diarrhoea in humans especially in association with administration of antibiotics. In pigs, C. difficile can cause neonatal ...enteritis and can be isolated from faeces from both diseased and healthy animals. The presented prospective study describes how soon C. difficile can be isolated from newborn piglets after normal parturition and how C. difficile spreads within a pig farm. Six sows, their farrowing crates and their litters at one farm were sampled until C. difficile was found in all piglets. Within 48h after birth, all 71 piglets became positive for C. difficile (two piglets were already positive within 1h post partum), all sows became positive within 113h after parturition and the farrowing crates were found intermittently positive. C. difficile could also be detected in air samples and in samples of teats of the sows. All isolates belonged to PCR ribotype 078. Twenty-one C. difficile ribotype 078 isolates, found at the farm, were further analyzed by MLVA (multiple-locus variable-number tandem repeat analysis) and belonged to one clonal complex, except one isolate.
To be sure that piglets were not born already infected with C. difficile ribotype 078, 38 caesarean derived piglets were sampled immediately after surgery. All piglets tested negative at delivery and stayed negative for C. difficile ribotype 078 during the 21 days in which they were kept in sterile incubators.
This study shows that C. difficile ribotype 078 spreads easily between sows, piglets and the environment. Vertical transmission of C. difficile ribotype 078 was not found and is very unlikely to occur.
We present the first spectroscopic study of the host environments of Type Ibc supernovae (SNe Ibc) discovered exclusively by untargeted SN searches. Past studies of SN Ibc host environments have been ...biased toward high-mass, high-metallicity galaxies by focusing on SNe discovered in galaxy-targeted SN searches. Our new observations more than double the total number of spectroscopic stellar population age and metallicity measurements published for untargeted SN Ibc host environments. We discuss the path forward for making progress on SN Ibc progenitor studies in the Large Synoptic Survey Telescope era. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.
We present optical spectroscopy and optical/near-IR photometry of 31 host galaxies of hydrogen-poor superluminous supernovae (SLSNe), including 15 events from the Pan-STARRS1 Medium Deep Survey. Our ...sample spans the redshift range 0.1 lap z lap 1.6, and is the first comprehensive host galaxy study of this specific subclass of cosmic explosions. Combining the multi-band photometry and emission-line measurements, we determine the luminosities, stellar masses, star formation rates, and metallicities. We find that, as a whole, the hosts of SLSNe are a low-luminosity (left angle bracketM sub(B)right angle bracket) approximately 17.3 mag), low stellar mass (left angle bracketM sub(*)right angle bracket) approximately 2 x 10 super(8) M sub(middot in circle)) population, with a high median specific star formation rate ((sSFR) approximately 2 Gyr super(-1)). The median metallicity of our spectroscopic sample is low, 12 + log(O/H) approximately 8.35 approximately 0.45 Z sub(middot in circle), although at least one host galaxy has solar metallicity. The host galaxies of H-poor SLSNe are statistically distinct from the hosts of GOODS core-collapse SNe (which cover a similar redshift range), but resemble the host galaxies of long-duration gamma-ray bursts (LGRBs) in terms of stellar mass, SFR, sSFR, and metallicity. This result indicates that the environmental causes leading to massive stars forming either SLSNe or LGRBs are similar, and in particular that SLSNe are more effectively formed in low metallicity environments. We speculate that the key ingredient is large core angular momentum, leading to a rapidly spinning magnetar in SLSNe and an accreting black hole in LGRBs.
The double explosion of SN 2009ip in 2012 raises questions about our understanding of the late stages of massive star evolution. Here we present a comprehensive study of SN 2009ip during its ...remarkable rebrightenings. High-cadence photometric and spectroscopic observations from the GeV to the radio band obtained from a variety of ground-based and space facilities (including the Very Large Array, Swift, Fermi, Hubble Space Telescope, and XMM) constrain SN 2009ip to be a low energy (E ~ 10 super(50) erg for an ejecta mass ~0.5 M sub(middot in circle)) and asymmetric explosion in a complex medium shaped by multiple eruptions of the restless progenitor star. Most of the energy is radiated as a result of the shock breaking out through a dense shell of material located at ~5 x 10 super(14)cm with M ~ 0.1 M sub(middot in circle), ejected by the precursor outburst ~40 days before the major explosion. We interpret the NIR excess of emission as signature of material located further out, the origin of which has to be connected with documented mass-loss episodes in the previous years. Our modeling predicts bright neutrino emission associated with the shock break-out if the cosmic-ray energy is comparable to the radiated energy. We connect this phenomenology with the explosive ejection of the outer layers of the massive progenitor star, which later interacted with material deposited in the surroundings by previous eruptions. Future observations will reveal if the massive luminous progenitor star survived. Irrespective of whether the explosion was terminal, SN 2009ip brought to light the existence of new channels for sustained episodic mass loss, the physical origin of which has yet to be identified.
We present ultraviolet, optical, and near-infrared observations of SN 2012ap, a broad-lined Type Ic supernova in the galaxy NGC1729 that produced a relativistic and rapidly decelerating outflow ...without a gamma-ray burst signature. Photometry and spectroscopy follow the flux evolution from -13 to +272 days past the B-band maximum of -17.4 + or - 0.5mag. The spectra are dominated by Fe II, OI, and Ca II absorption lines at ejecta velocities of v approximate 20,000 km ssup -1 that change slowly over time. Other spectral absorption lines are consistent with contributions from photo-spheric He I, and hydrogen may also be present at higher velocities. SN 2012ap joins SN2009bb as another exceptional supernova that shows evidence for a central engine capable of launching a non-negligible portion of ejecta to relativistic velocities without a coincident gamma-ray burst detection. The events support the notion that jet activity at various energy scales may be present in a wide range of supernovae.
Solar-induced fluorescence (SIF) data from satellites are increasingly used as a proxy for photosynthetic activity by vegetation, and as a constraint on gross primary production. Here we report on ...improvements in the algorithm to retrieve mid-morning (09:30 hrs local time) SIF estimates on the global scale from GOME-2 sensor on the Metop-A satellite (GOME-2A) for the period 2007-2019. Our new SIFTER (Sun-Induced Fluorescence of Terrestrial Ecosystems Retrieval) v2 algorithm improves over a previous version by using a narrower spectral window that avoids strong oxygen absorption and is less sensitive to water vapour absorption, by constructing stable reference spectra from a 6-year period (2007-2012) of atmospheric spectra over the Sahara, and by applying a latitude-dependent zero-level adjustment that accounts for biases in the data product. We generated stable, good-quality SIF retrievals between January 2007 and June 2013, when GOME-2A degradation in the near infrared was still limited. After the narrowing of the GOME-2A swath in July 2013, we characterized the throughput degradation of the level-1 data in order to derive reflectance corrections and apply these for the SIF retrievals between July 2013 and December 2018. SIFTER v2 data compares well with the independent NASA v2.8 data product. Especially in the evergreen tropics, SIFTER v2 no longer shows the underestimates against other satellite products that were seen in SIFTER v1. The new data product includes uncertainty estimates for individual observations, and is best used for mostly clear-sky scenes, and when spectral residuals remain below a certain spectral autocorrelation threshold. Our results support the use of SIFTER v2 data to be used as an independent constraint on photosynthetic activity on regional to global scales.
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