A first direct measurement of the intergalactic medium temperature around a quasar at z=6

The thermal state of the intergalactic medium (IGM) provides an indirect probe of both the HI and HeII reionisation epochs. Current constraints on the IGM temperature from the Lya forest are restricted to the redshift range 2<z<4.5, limiting the ability to probe the thermal memory of HI reionisation toward higher redshift. In this work, we present the first direct measurement of the IGM temperature around a z=6 quasar by analysing the Doppler widths of Lya absorption lines in the proximity zone of SDSS J0818+1722. We use a high resolution (R= 40000) Keck/HIRES spectrum in combination with detailed numerical modelling to obtain the temperature at mean density, T_0=23600\pm^5000_6900K (\pm^9200_9300K) at 68 (95) per cent confidence assuming a prior probability 13500K<T_0<38500 K following HI and HeII reionisation. This enables us to place an upper limit on the redshift of HI reionisation, z_H, within 33 comoving Mpc of SDSS J0818+1722. If the quasar reionises the HeII in its vicinity, then in the limit of instantaneous reionisation we infer z_H<9.0 (11.0) at 68 (95) per cent confidence assuming photoheating is the dominant heat source and that HI reionisation is driven by ionising sources with soft spectra, typical of population II stars. If the HI and HeII in the IGM around SDSS J0818+1722 are instead reionised simultaneously by a population of massive metal-free stars, characterised by very hard ionising spectra, we obtain a tighter upper limit of z_H<8.4 (9.4). Initiating reionisation at higher redshifts produces temperatures which are too low with respect to our constraint unless the HI ionising sources or the quasar itself have spectra significantly harder than typically assumed.Comment: 15 pages, 9 figures, accepted to MNRA

Business in Nebraska # 278 - November 1967

The Nebraska Department of Economic Development (James W. Monroe) After 100 years of growth and prosperity based firmly upon a nearly self-sufficient agricultural economy, why has Nebraska seen fit to depart from its rural image and increase its efforts in the highly competitive business of attracting industry? Business Summary (E. L. Burgess) August\u27s dollar volume of business in Nebraska increased 3.3% from August, 1966 and the physical volume increased 2.7%. The U.S. dollar volume rose 5.3% from August, 1966. The U.S. construction activity index increased over year-ago levels for the first time since May, 1966. Nebraska\u27s construction index, having last shown an increase over year-ago levels in September, 1966, remained down with a 14.3% decline from August, 1966. Life insurance sales (-1.1%) was the only other Nebraska indicator declining from year-ago levels. Review (E. S. Wallace

Cerebral dehydration action of glycerol; I. Historical aspects with emphasis on the toxicity and intravenous administration

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/117051/1/cpt1972132159.pd

CCD photometry of the nuclei of three supergiant elliptical galaxies - Evidence for a supermassive object in the center of the radio galaxy NGC 6251

We have analyzed charged coupled device (CCD) photometry in the g and r bands of three supergiant elliptical galaxies: NGC 4874 and NGC 4889 in the Coma cluster, and the radio galaxy NGC 6251. The profiles of NGC 4874 and NGC 4889 are closely fitted by King models. The profile of NGC 6251 cannot be fitted by a King model, nor by a King model plus a central point luminosity source (the presence of which is suggested by a blue trend in the colors at small radii). The previously studied profile of M87, when convolved with an appropriate Gaussian function to allow for the difference in distance, closely resembles the profile of NGC 6251 (but not those of NGC 4874 or NGC 4889). NGC 6251 was successfully fitted with a luminosity profile containing both a point luminosity source and a central point mass. The value of this point mass cannot be determined without additional dynamical data. However, if the core velocity dispersion is similar to that of other giant ellipticals of the same absolute magnitude, the point mass is likely to be about 2.4 x 10^9 M_⊙, similar to the value reported earlier for M87. The data are also used to derive upper limits for possible central point masses in NGC 4874 and NGC 4889

Species richness and soil properties in Pinus ponderosa forests: A structural equation modeling analysis

Question: How are the effects of mineral soil properties on understory plant species richness propagated through a network of processes involving the forest overstory, soil organic matter, soil nitrogen, and understory plant abundance? Location: North-central Arizona, USA. Methods: We sampled 75 0.05-ha plots across a broad soil gradient in a Pinus ponderosa (ponderosa pine) forest ecosystem. We evaluated multivariate models of plant species richness using structural equation modeling. Results: Richness was highest at intermediate levels of understory plant cover, suggesting that both colonization success and competitive exclusion can limit richness in this system. We did not detect a reciprocal positive effect of richness on plant cover. Richness was strongly related to soil nitrogen in the model, with evidence for both a direct negative effect and an indirect non-linear relationship mediated through understory plant cover. Soil organic matter appeared to have a positive influence on understory richness that was independent of soil nitrogen. Richness was lowest where the forest overstory was densest, which can be explained through indirect effects on soil organic matter, soil nitrogen and understory cover. Finally, model results suggest a variety of direct and indirect processes whereby mineral soil properties can influence richness. Conclusions: Understory plant species richness and plant cover in P. ponderosa forests appear to be significantly influenced by soil organic matter and nitrogen, which are, in turn, related to overstory density and composition and mineral soil properties. Thus, soil properties can impose direct and indirect constraints on local species diversity in ponderosa pine forests

Effects of d‐amphetamine on quantitative measures of motor performance

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/117170/1/cpt1972132251.pd

Cylindrical surface profile and diameter measuring tool and method

A tool is shown having a cross beam assembly made of beams joined by a center box structure. The assembly is adapted to be mounted by brackets to the outer end of a cylindrical case. The center box structure has a vertical shaft rotatably mounted therein and extending beneath the assembly. Secured to the vertical shaft is a radius arm which is adapted to rotate with the shaft. On the longer end of the radius arm is a measuring tip which contacts the cylindrical surface to be measured and which provides an electric signal representing the radius of the cylindrical surface from the center of rotation of the radius arm. An electric servomotor rotates the vertical shaft and an electronic resolver provides an electric signal representing the angle of rotation of the shaft. The electric signals are provided to a computer station which has software for its computer to calculate and print out the continuous circumference profile of the cylindrical surface, and give its true diameter and the deviations from the ideal circle