Triple-ionised carbon associated with the low-density neutral hydrogen gas at 1.7 < z < 3.3: the integrated N(HI)-N(CIV) relation

From the Voigt profile fitting analysis of 183 intervening CIV systems at 1.7 < z < 3.3 in 23 high-quality UVES/VLT and HIRES/Keck QSO spectra, we find that a majority of CIV systems (~75%) display a well-characterised scaling relation between integrated column densities of HI and CIV with a negligible redshift evolution, when column densities of all the HI and CIV components are integrated within a given (-150, +150) km/sec range centred at the CIV flux minimum. The integrated CIV column density N(CIV, sys) increases with N(HI, sys) at log N(HI, sys) = 14.0--15.5 and log N(CIV, sys) = 11.8--14.0, then becomes almost independent of N(HI, sys) at log N(HI, sys) > 16, with a large scatter: at log N(HI, sys) = 14--22, log N(CIV, sys) = C1 / (log(NHI, sys) + C2) + C3, with C1 = -1.90+0.55, C2 = -14.11+0.19 and C3 = 14.76+0.17, respectively. The steep (flat) part is dominated by SiIV-free (SiIV-enriched) CIV systems. Extrapolating the N(HI, sys)-N(CIV, sys) relation implies that most absorbers with log N(HI) < 14 are virtually CIV-free. The N(HI, sys)-N(CIV, sys) relation does not hold for individual components, clumps or the integration velocity range less than +-100 km/sec. It is expected if the line-of-sight extent of CIV is smaller than HI and N(CIV, sys) decreases more rapidly than N(HI, sys) at the larger impact parameter, regardless of the location of the HI+CIV gas in the IGM filaments or in the intervening galactic halos.Comment: Accepted for publication on MNRAS, 26 pages, 20 figures, 4 tables. On-line materials are found in the submitted civ.tar.gz file: complete Table 2, complete Table 3, complete Table 4, velocity plots civ1.pdf, civ2.pdf, civ3.pdf, civ4.pdf and civ5.pd

Spectroscopic Analysis of H I Absorption Line Systems in 40 HIRES Quasars

We list and analyze H I absorption lines at redshifts 2 < z < 4 with column density (12 < log(N_HI) < 19) in 40 high-resolutional (FWHM = 8.0 km/s) quasar spectra obtained with the Keck+HIRES. We de-blend and fit all H I lines within 1,000 km/s of 86 strong H I lines whose column densities are log(N_HI/[cm^-2]) > 15. Unlike most prior studies, we use not only Lya but also all visible higher Lyman series lines to improve the fitting accuracy. This reveals components near to higher column density systems that can not be seen in Lya. We list the Voigt profile fits to the 1339 H I components that we found. We examined physical properties of H I lines after separating them into several sub-samples according to their velocity separation from the quasars, their redshift, column density and the S/N ratio of the spectrum. We found two interesting trends for lines with 12 < log(N_HI) < 15 which are within 200-1000 km/s of systems with log(N_HI) > 15. First, their column density distribution becomes steeper, meaning relatively fewer high column density lines, at z < 2.9. Second, their column density distribution also becomes steeper and their line width becomes broader by about 2-3 km/s when they are within 5,000 km/s of their quasar.Comment: 32 pages, 14 figures, accepted for publication in the Astronomical Journal. A complete version with all tables and figures is available at http://www.astro.psu.edu/users/misawa/pub/Paper/40hires.ps.g

The Transverse Proximity Effect: A Probe to the Environment, Anisotropy, and Megayear Variability of QSOs

The transverse proximity effect is the expected decrease in the strength of the Lya forest absorption in a QSO spectrum when another QSO lying close to the line of sight enhances the photoionization rate above that due to the average cosmic ionizing background. We select three QSOs from the Early Data Release of the Sloan Digital Sky Survey that have nearby foreground QSOs, with proper line of sight tangential separations of 0.50, 0.82, and 1.10 h^{-1} Mpc. We estimate that the ionizing flux from the foreground QSO should increase the photoionization rate by a factor (94, 13, 13) in these three cases, which would be clearly detectable in the first QSO and marginally so in the other two. We do not detect the transverse proximity effect. Three possible explanations are provided: an increase of the gas density in the vicinity of QSOs, time variability, and anisotropy of the QSO emission. We find that the increase of gas density near QSOs can be important if they are located in the most massive halos present at high redshift, but is not enough to fully explain the absence of the transverse proximity effect. Anisotropy requires an unrealistically small opening angle of the QSO emission. Variability demands that the luminosity of the QSO with the largest predicted effect was much lower 10^6 years ago, whereas the transverse proximity effect observed in the HeII Lya absorption in QSO 0302-003 by Jakobsen et al. (2003) implies a lifetime longer than 10^7 years. A combination of all three effects may better explain the lack of Lya absorption reduction. A larger sample of QSO pairs may be used to diagnose the environment, anisotropy and lifetime distribution of QSOs.Comment: 27 pages, 13 figures, accepted by Ap

Genome-wide association study of behavioural and psychiatric features in human prion disease.

Prion diseases are rare neurodegenerative conditions causing highly variable clinical syndromes, which often include prominent neuropsychiatric symptoms. We have recently carried out a clinical study of behavioural and psychiatric symptoms in a large prospective cohort of patients with prion disease in the United Kingdom, allowing us to operationalise specific behavioural/psychiatric phenotypes as traits in human prion disease. Here, we report exploratory genome-wide association analysis on 170 of these patients and 5200 UK controls, looking for single-nucleotide polymorphisms (SNPs) associated with three behavioural/psychiatric phenotypes in the context of prion disease. We also specifically examined a selection of candidate SNPs that have shown genome-wide association with psychiatric conditions in previously published studies, and the codon 129 polymorphism of the prion protein gene, which is known to modify various aspects of the phenotype of prion disease. No SNPs reached genome-wide significance, and there was no evidence of altered burden of known psychiatric risk alleles in relevant prion cases. SNPs showing suggestive evidence of association (P<10(-5)) included several lying near genes previously implicated in association studies of other psychiatric and neurodegenerative diseases. These include ANK3, SORL1 and a region of chromosome 6p containing several genes implicated in schizophrenia and bipolar disorder. We would encourage others to acquire phenotype data in independent cohorts of patients with prion disease as well as other neurodegenerative and neuropsychiatric conditions, to allow meta-analysis that may shed clearer light on the biological basis of these complex disease manifestations, and the diseases themselves

Exploring Spatial Business Data: A ROA Based eCampus Application

In Smart environments development, providing users with search utilities for interacting efficiently with web and wireless devices is a key goal. At smaller scales, Google Maps and Google Earth with satellite and street views have helped users for querying general information at specific locations. However, at larger local scales, where detailed 3D geometries linked to business data are needed, there is a recognized lack of related information and functionality for in depth exploration of an area. Linking spatial data and business data helps to enrich the user experience by fulfilling more task specific user needs. This paper presents an eCampus Demonstrator for the National University of Ireland, Maynooth (NUIM) based on a Resource Oriented Architecture (ROA), in which various RESTful web-services have been developed and deployed for querying both spatial data and associated business data. The benefits and drawbacks of the chosen technologies are also discussed. This work can be considered as a platform that can be applied to similar application domains such as exploring business parks, hospitals, museums, etc

Short-term biotic removal of dissolved organic nitrogen (DON) compounds from soil solution and subsequent mineralisation in contrasting grassland soils

Cycling of low molecular weight dissolved organic nitrogen compounds constitutes an important component of soil organic matter turnover in soils. We determined how rapidly grassland soils can cycle urea, compared to the amino acid l-alanine, and the peptide l-trialanine. Using naturally occurring concentrations of 14C-labelled compounds the rates of removal from soil solution and subsequent mineralisation were measured. Biotic removal of all three compounds and subsequent mineralisation to CO2 occurred within minutes. This research has demonstrated, for the first time, the potential for rapid removal of urea at low concentrations by the soil microbial biomass

A Uniform Analysis of the Ly-alpha forest at z = 0 - 5: I. The sample and distribution of clouds at z > 1.7

We present moderate resolution data for 39 QSOs at z $\approx$ 2 obtained at the Multiple Mirror Telescope. These data are combined with spectra of comparable resolution of 60 QSOs with redshifts greater than 1.7 found in the literature to investigate the distribution of Ly-alpha forest lines in redshift and equivalent width. We find a value for $\gamma$, the parameter describing the number distribution of Ly-alpha forest lines in redshift, of $1.88\pm0.22$ for lines stronger than a rest equivalent width of 0.32 $\AA$, in good agreement with some previous studies. The Kolmogorov-Smirnov test was applied to the data and it is found that this single power law is a good fit over the relevant redshift ranges. Simulations of the Lyman alpha forest were performed to determine the completeness of the line lists and to test how well the analysis the underlying line statistics, given this level of completeness.Comment: minor corrections to text, 37 Latex pages, 11 encapsulated Postscript figures, uses emulateapj.sty, To appear in the Sept. 2000 ApJS, line lists and spectra available at http://qso.as.arizona.edu/~jscott/Spectra/index.htm

Participatory research to design a novel system to support the night-time needs of people with dementia; NOCTURNAL

Strategies to support people living with dementia are broad in scope, proposing both pharmacological and non-pharmacological interventions as part of the care pathway. Assistive technologies form part of this offering as both stand-alone devices to support particular tasks and the more complex offering of the “smart home” to underpin ambient assisted living. This paper presents a technology-based system, which expands on the smart home architecture, orientated to support people with daily living. The system, NOCTURNAL, was developed by working directly with people who had dementia, and their carers using qualitative research methods. The research focused primarily on the nighttime needs of people living with dementia in real home settings. Eight people with dementia had the final prototype system installed for a three month evaluation at home. Disturbed sleep patterns, night-time wandering were a focus of this research not only in terms of detection by commercially available technology but also exploring if automated music, light and visual personalized photographs would be soothing to participants during the hours of darkness. The NOCTURNAL platform and associated services was informed by strong user engagement of people with dementia and the service providers who care for them. NOCTURNAL emerged as a holistic service offering a personalised therapeutic aspect with interactive capabilities

The Primordial Abundance of He4: An Update

We include new data in an updated analysis of helium in low metallicity extragalactic HII regions with the goal of deriving the primordial abundance of He4 (Y_P). We show that the new observations of Izotov et al (ITL) are consistent with previous data. However they should not be taken in isolation to determine (Y_P) due to the lack of sufficiently low metallicity points. We use the extant data in a semi-empirical approach to bounding the size of possible systematic uncertainties in the determination of (Y_P). Our best estimate for the primordial abundance of He4 assuming a linear relation between He4 and O/H is Y_P = 0.230 \pm 0.003 (stat) based on the subset of HII regions with the lowest metallicity; for our full data set we find Y_P = 0.234 \pm 0.002 (stat). Both values are entirely consistent with our previous results. We discuss the implications of these values for standard big bang nucleosynthesis (SBBN), particularly in the context of recent measurements of deuterium in high redshift, low metallicity QSO absorption-line systems.Comment: 26 pages, latex, 6 ps figure