2,390 research outputs found

    Joint Planes in the Rhyolites of the Butte District, Montana

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    The problem herein discussed deals with the pointing planes found in the area of rhyolite located in the northwestern portion of the Butte District. The question to be determined was whether or not the pointing planes in the rhyolites could be class­ified with the Butte Ore fissure systems

    Experience of some Iowa farmers with cattle feeding

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    The cattle feeder’s main purpose is to get the largest possible returns from his cattle with the amount of feed, capital and labor that he has available. Naturally, returns from the farm as a whole are more important than the success of any one enterprise, but the management of the entire farm involves many more questions than we can discuss adequately in this short bulletin. Therefore we shall simply present information obtained in 1938 and 1939 on the more common methods of Iowa cattle feeders. Results will be discussed solely on the basis of the cattle-feeding enterprise itself

    Active tuning of high-Q dielectric metasurfaces

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    We demonstrate the active tuning of all-dielectric metasurfaces exhibiting high-quality factor (high-Q) resonances. The active control is provided by embedding the asymmetric silicon meta-atoms with liquid crystals, which allows the relative index of refraction to be controlled through heating. It is found that high quality factor resonances (Q=270±30Q=270\pm30) can be tuned over more than three resonance widths. Our results demonstrate the feasibility of using all-dielectric metasurfaces to construct tunable narrow-band filters.Comment: 4 pages, 6 figure

    Preparing an Election Petition in Missouri

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    Initiative and referendum petitions provide citizens with the power to make and overturn existing laws. Through the initiative petition, the people can compel an election on the question of enacting an amendment to the Missouri Constitution or enacting a proposed law. Through the referendum petition, the people can compel an election to decide whether an existing law should be retained. The procedure to be followed in drafting these petitions is specified in the Constitution and Statutes of Missouri.Reviewed October 1993

    The Star Formation Rate in the Reionization Era as Indicated by Gamma-ray Bursts

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    High-redshift gamma-ray bursts (GRBs) offer an extraordinary opportunity to study aspects of the early Universe, including the cosmic star formation rate (SFR). Motivated by the two recent highest-z GRBs, GRB 080913 at z = 6.7 and GRB 090423 at z = 8.1, and more than four years of Swift observations, we first confirm that the GRB rate does not trace the SFR in an unbiased way. Correcting for this, we find that the implied SFR to beyond z = 8 is consistent with LBG-based measurements after accounting for unseen galaxies at the faint end of the UV luminosity function. We show that this provides support for the integrated star formation in the range 6 < z < 8 to have been alone sufficient to reionize the Universe.Comment: 4 pages, 4 figures; modified to match version accepted for publication in ApJ Letter

    The Large Area Radio Galaxy Evolution Spectroscopic Survey (LARGESS): survey design, data catalogue and GAMA/WiggleZ spectroscopy

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    © 2016 The Authors. We present the Large Area Radio Galaxy Evolution Spectroscopic Survey (LARGESS), a spectroscopic catalogue of radio sources designed to include the full range of radio AGN populations out to redshift z ~ 0.8. The catalogue covers ~800 deg 2 of sky, and provides optical identifications for 19 179 radio sources from the 1.4 GHz Faint Images of the Radio Sky at Twenty-cm (FIRST) survey down to an optical magnitude limit of i mod < 20.5 in Sloan Digital Sky Survey (SDSS) images. Both galaxies and point-like objects are included, and no colour cuts are applied. In collaboration with the WiggleZ and Galaxy And Mass Assembly (GAMA) spectroscopic survey teams, we have obtained new spectra for over 5000 objects in the LARGESS sample. Combining these new spectra with data from earlier surveys provides spectroscopic data for 12 329 radio sources in the survey area, of which 10 856 have reliable redshifts. 85 per cent of the LARGESS spectroscopic sample are radio AGN (median redshift z = 0.44), and 15 per cent are nearby star-forming galaxies (median z = 0.08). Low-excitation radio galaxies (LERGs) comprise the majority (83 per cent) of LARGESS radio AGN at z < 0.8, with 12 per cent being high-excitation radio galaxies (HERGs) and 5 per cent radioloud QSOs. Unlike the more homogeneous LERG and QSO sub-populations, HERGs are a heterogeneous class of objects with relatively blue optical colours and a wide dispersion in mid-infrared colours. This is consistent with a picture in which most HERGs are hosted by galaxies with recent or ongoing star formation as well as a classical accretion disc

    Stable Isotopes Confirm a Coastal Diet for Critically Endangered Mediterranean Monk Seals

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    Understanding the ecology and behaviour of endangered species is essential for developing effective management and conservation strategies.We used stable isotope analysis to investigate the foraging behaviour of critically endangered Mediterranean monk seals (Monachus monachus) in Greece.We measured carbon and nitrogen isotope ratios (expressed as δ13C and δ15N values, respectively) derived from the hair of deceased adult and juvenile seals and the muscle of their known prey to quantify their diets.We tested the hypothesis that monk seals primarily foraged for prey that occupy coastal habitats in Greece.We compared isotope values from seal hair to their coastal and pelagic prey (after correcting all prey for isotopic discrimination) and used these isotopic data and a stable isotope mixing model to estimate the proportion of coastal and pelagic resources consumed by seals. As predicted, we found that seals had similar δ13C values as many coastal prey species and higher δ13C values than pelagic species; these results, in conjunction with mean dietary estimates (coastal = 61 % vs. pelagic = 39 %), suggest that seals have a diverse diet comprising prey from multiple trophic levels that primarily occupy the coast. Marine resource managers should consider using the results from this study to inform the future management of coastal habitats in Greece to protect Mediterranean monk seals

    The role of nω-nitro-L-arginine in modulation of pulmonary vascular tone in the maturing newborn pig

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    AbstractCurrent therapeutic modalities for treatment of newborn pulmonary hypertensive crisis include but are not limited to the administration of nitric oxide (endothelium-derived relaxing factor). However, few data are available on the role of endogenously produced endothelium-derived relaxing factor in the modulation of pulmonary vascular tone in the neonate. In the current study, we investigated the acute effects of Nω-nitro- L -arginine (a potent competitive inhibitor of endothelium-derived relaxing factor synthase) on the pulmonary vasculature of anesthetized open-chest 48-hour-old ( n = 8) and 2-week-old ( n = 7) Yorkshire pigs. After baseline data were acquired, all animals received a 10 mg/kg per minute infusion of Nω-nitro- L -arginine for 10 minutes. To discern distal and proximal pulmonary arterial vessel changes, input mean and characteristic impedance were respectively determined. Pulmonary vascular resistance was also calculated (units determined in dyne • sec • cm -5 plus or minus the standard errorof the mean). Results showed Nω-nitro- L -arginine infusion did not significantly alter baseline pulmonary arterial pressure (22,370 ±1473 dyne/cm2 ), pulmonary vascular resistance (5171 ±805 dyne • sec • cm -5 ), input impedance (6343 ±806 dyne • sec • cm -5 ), or characteristic impedance (2073 ±418 dyne • sec • cm -5 ) in 48-hour-old pigs. In 2-week-old pigs, infusion of Nω-nitro- L -arginine elevated pulmonary arterial pressure (18,162 ±1415 dyne/cm 2 versus 23,838 ±1810 dyne/cm 2 , p = 0.015), pulmonary vascular resistance (810 ±137 dyne • sec • cm -5 versus 1519 dyne • sec • cm -5 , p = 0.030), and input impedance (2302 ±251 dyne • sec • cm -5 versus 2900 ±255 dyne • sec • cm -5 , p = 0.018). Characteristic impedance was not altered in 2-week-old pigs. These data indicate that Nω-nitro- L -arginine infusion resulted in pulmonary arteriolar vasoconstriction in 2-week-old pigs, but not in 48-hour-old pigs. This finding suggests that endothelium-derived relaxing factor does not modulate basal pulmonary arteriolar tone during the early newborn period, but does play a significant role in 2-week-old pigs. These data also suggest that the functional role for endothelium-derived relaxing factor is confined to the distal arteriolar pulmonary bed and does not extend to the larger proximal arterial vessels. (J THORAC CARDIOVASC SURG 1995;110:1486-92

    Eddington-limited accretion and the black hole mass function at redshift 6

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    We present discovery observations of a quasar in the Canada-France High-z Quasar Survey (CFHQS) at redshift z=6.44. We also use near-IR spectroscopy of nine CFHQS quasars at z~6 to determine black hole masses. These are compared with similar estimates for more luminous Sloan Digital Sky Survey (SDSS) quasars to investigate the relationship between black hole mass and quasar luminosity. We find a strong correlation between MgII FWHM and UV luminosity and that most quasars at this early epoch are accreting close to the Eddington limit. Thus these quasars appear to be in an early stage of their life cycle where they are building up their black hole mass exponentially. Combining these results with the quasar luminosity function, we derive the black hole mass function at z=6. Our black hole mass function is ~10^4 times lower than at z=0 and substantially below estimates from previous studies. The main uncertainties which could increase the black hole mass function are a larger population of obscured quasars at high-redshift than is observed at low-redshift and/or a low quasar duty cycle at z=6. In comparison, the global stellar mass function is only ~10^2 times lower at z=6 than at z=0. The difference between the black hole and stellar mass function evolution is due to either rapid early star formation which is not limited by radiation pressure as is the case for black hole growth or inefficient black hole seeding. Our work predicts that the black hole mass - stellar mass relation for a volume-limited sample of galaxies declines rapidly at very high redshift. This is in contrast to the observed increase at 4<z<6 from the local relation if one just studies the most massive black holes.Comment: 16 pages, 10 figures, AJ in pres

    Measurement of the Condensation Coefficient of Water in the UMR Cloud Simulation Chamber

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    Measurements of the condensation coefficient of water under conditions closely approximating those in natural atmospheric cloud have been made in the cooled-wall UMR cloud simulation chamber. Current measurements disclose a value of condensation coefficient near unity at the outset of the experiment, generally decreasing to lower values (~ .01) as the experiment progresses. The significance of the magnitude of condensation coefficient in atmospheric cloud is briefly discussed
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