Colors of 2625 Quasars at 0<z<5 Measured in the Sloan Digital Sky Survey Photometric System

We present an empirical investigation of the colors of quasars in the Sloan Digital Sky Survey (SDSS) photometric system. The sample studied includes 2625 quasars with SDSS photometry. The quasars are distributed in a 2.5 degree wide stripe centered on the Celestial Equator covering $\sim529$ square degrees. Positions and SDSS magnitudes are given for the 898 quasars known prior to SDSS spectroscopic commissioning. New SDSS quasars represent an increase of over 200% in the number of known quasars in this area of the sky. The ensemble average of the observed colors of quasars in the SDSS passbands are well represented by a power-law continuum with $\alpha_{\nu} = -0.5$ ($f_{\nu} \propto \nu^{\alpha}$). However, the contributions of the $3000 {\rm \AA}$ bump and other strong emission lines have a significant effect upon the colors. The color-redshift relation exhibits considerable structure, which may be of use in determining photometric redshifts for quasars. The range of colors can be accounted for by a range in the optical spectral index with a distribution $\alpha_{\nu}=-0.5\pm0.65$ (95% confidence), but there is a red tail in the distribution. This tail may be a sign of internal reddening. Finally, we show that there is a continuum of properties between quasars and Seyfert galaxies and we test the validity of the traditional division between the two classes of AGN.Comment: 66 pages, 15 figures (3 color), accepted by A

The Sloan Digital Sky Survey Quasar Catalog I. Early Data Release

We present the first edition of the Sloan Digital Sky Survey (SDSS) Quasar Catalog. The catalog consists of the 3814 objects (3000 discovered by the SDSS) in the initial SDSS public data release that have at least one emission line with a full width at half maximum larger than 1000 km/s, luminosities brighter than M_i^* = -23, and highly reliable redshifts. The area covered by the catalog is 494 square degrees; the majority of the objects were found in SDSS commissioning data using a multicolor selection technique. The quasar redshifts range from 0.15 to 5.03. For each object the catalog presents positions accurate to better than 0.2" rms per coordinate, five band (ugriz) CCD-based photometry with typical accuracy of 0.05 mag, radio and X-ray emission properties, and information on the morphology and selection method. Calibrated spectra of all objects in the catalog, covering the wavelength region 3800 to 9200 Angstroms at a spectral resolution of 1800-2100, are also available. Since the quasars were selected during the commissioning period, a time when the quasar selection algorithm was undergoing frequent revisions, the sample is not homogeneous and is not intended for statistical analysis.Comment: 27 pages, 4 figures, 4 tables, accepted by A

The First Hour of Extra-galactic Data of the Sloan Digital Sky Survey Spectroscopic Commissioning: The Coma Cluster

On 26 May 1999, one of the Sloan Digital Sky Survey (SDSS) fiber-fed spectrographs saw astronomical first light. This was followed by the first spectroscopic commissioning run during the dark period of June 1999. We present here the first hour of extra-galactic spectroscopy taken during these early commissioning stages: an observation of the Coma cluster of galaxies. Our data samples the Southern part of this cluster, out to a radius of 1.5degrees and thus fully covers the NGC 4839 group. We outline in this paper the main characteristics of the SDSS spectroscopic systems and provide redshifts and spectral classifications for 196 Coma galaxies, of which 45 redshifts are new. For the 151 galaxies in common with the literature, we find excellent agreement between our redshift determinations and the published values. As part of our analysis, we have investigated four different spectral classification algorithms: spectral line strengths, a principal component decomposition, a wavelet analysis and the fitting of spectral synthesis models to the data. We find that a significant fraction (25%) of our observed Coma galaxies show signs of recent star-formation activity and that the velocity dispersion of these active galaxies (emission-line and post-starburst galaxies) is 30% larger than the absorption-line galaxies. We also find no active galaxies within the central (projected) 200 h-1 Kpc of the cluster. The spatial distribution of our Coma active galaxies is consistent with that found at higher redshift for the CNOC1 cluster survey. Beyond the core region, the fraction of bright active galaxies appears to rise slowly out to the virial radius and are randomly distributed within the cluster with no apparent correlation with the potential merger of the NGC 4839 group. [ABRIDGED]Comment: Accepted in AJ, 65 pages, 20 figures, 5 table

Galaxy Clustering in Early SDSS Redshift Data

We present the first measurements of clustering in the Sloan Digital Sky Survey (SDSS) galaxy redshift survey. Our sample consists of 29,300 galaxies with redshifts 5,700 km/s < cz < 39,000 km/s, distributed in several long but narrow (2.5-5 degree) segments, covering 690 square degrees. For the full, flux-limited sample, the redshift-space correlation length is approximately 8 Mpc/h. The two-dimensional correlation function \xi(r_p,\pi) shows clear signatures of both the small-scale, ``fingers-of-God'' distortion caused by velocity dispersions in collapsed objects and the large-scale compression caused by coherent flows, though the latter cannot be measured with high precision in the present sample. The inferred real-space correlation function is well described by a power law, \xi(r)=(r/6.1+/-0.2 Mpc/h)^{-1.75+/-0.03}, for 0.1 Mpc/h < r < 16 Mpc/h. The galaxy pairwise velocity dispersion is \sigma_{12} ~ 600+/-100 km/s for projected separations 0.15 Mpc/h < r_p < 5 Mpc/h. When we divide the sample by color, the red galaxies exhibit a stronger and steeper real-space correlation function and a higher pairwise velocity dispersion than do the blue galaxies. The relative behavior of subsamples defined by high/low profile concentration or high/low surface brightness is qualitatively similar to that of the red/blue subsamples. Our most striking result is a clear measurement of scale-independent luminosity bias at r < 10 Mpc/h: subsamples with absolute magnitude ranges centered on M_*-1.5, M_*, and M_*+1.5 have real-space correlation functions that are parallel power laws of slope ~ -1.8 with correlation lengths of approximately 7.4 Mpc/h, 6.3 Mpc/h, and 4.7 Mpc/h, respectively.Comment: 51 pages, 18 figures. Replaced to match accepted ApJ versio

Using a private 5G network to support the international broadcast of the coronation of HM King Charles III

Wireless cameras for news contribution feeds regularly use “bonded-cellular” devices, which connect to and split the encoded video across multiple public mobile network SIMs. However, in high demand density environments with large crowds, the public networks can quickly become saturated and unable to sustain the necessary bitrates to support high-definition video. To overcome this and provide uncontested wireless connectivity, the largest pop-up 5G standalone non-public (private) network of its type was deployed outside Buckingham Palace and along The Mall to Admiralty Arch to support news contributions for domestic and foreign broadcasters at the Coronation of HM King Charles III, without changing the contribution workflow. (This paper first appeared in the Proceedings of the 2024 NAB Broadcast Engineering and Information Technology Conference, and is reprinted with permission. https://nabpilot.org/beitc-proceedings/

TrpA1 Regulates Thermal Nociception in Drosophila

Pain is a significant medical concern and represents a major unmet clinical need. The ability to perceive and react to tissue-damaging stimuli is essential in order to maintain bodily integrity in the face of environmental danger. To prevent damage the systems that detect noxious stimuli are therefore under strict evolutionary pressure. We developed a high-throughput behavioral method to identify genes contributing to thermal nociception in the fruit fly and have reported a large-scale screen that identified the Ca2+ channel straightjacket (stj) as a conserved regulator of thermal nociception. Here we present the minimal anatomical and neuronal requirements for Drosophila to avoid noxious heat in our novel behavioral paradigm. Bioinformatics analysis of our whole genome data set revealed 23 genes implicated in Ca2+ signaling that are required for noxious heat avoidance. One of these genes, the conserved thermoreceptor TrpA1, was confirmed as a bona fide “pain” gene in both adult and larval fly nociception paradigms. The nociceptive function of TrpA1 required expression within the Drosophila nervous system, specifically within nociceptive multi-dendritic (MD) sensory neurons. Therefore, our analysis identifies the channel TRPA1 as a conserved regulator of nociception

Solar System Objects Observed in the SDSS Commissioning Data

We discuss measurements of the properties of about 10,000 asteroids detected in 500 deg2 of sky in the Sloan Digital Sky Survey (SDSS) commissioning data. The moving objects are detected in the magnitude range 14 < r < 21.5, with a baseline of 5 minutes. Extensive tests show that the sample is at least 98% complete, with the contamination rate of less than 3%. We find that the size distribution of asteroids resembles a broken power-law, independent of the heliocentric distance: D^{-2.3} for 0.4 km < D < 5 km, and D^{-4} for 5 km < D < 40 km. As a consequence of this break, the number of asteroids with r < 21.5 is ten times smaller than predicted by extrapolating the power-law relation observed for brighter asteroids (r < 18). The observed counts imply that there are about 530,000 objects with D>1 km in the asteroid belt, or about four times less than previous estimates. The distribution of main belt asteroids in the 4-dimensional SDSS color space is bimodal, and the two groups can be associated with S (rocky) and C (carbonaceous) asteroids. A strong bimodality is also seen in the heliocentric distribution of asteroids and suggests the existence of two distinct belts: the inner rocky belt, about 1 AU wide (FWHM) and centered at R~2.8 AU, and the outer carbonaceous belt, about 0.5 AU wide and centered at R~3.2 AU. The colors of Hungarias, Mars crossers, and near-Earth objects are more similar to the C-type than to S-type asteroids, suggesting that they originate in the outer belt. (abridged).Comment: 89 pages, 31 figures, submitted to A

Molecular Investigations of a Locally Acquired Case of Melioidosis in Southern AZ, USA

Melioidosis is caused by Burkholderia pseudomallei, a Gram-negative bacillus, primarily found in soils in Southeast Asia and northern Australia. A recent case of melioidosis in non-endemic Arizona was determined to be the result of locally acquired infection, as the patient had no travel history to endemic regions and no previous history of disease. Diagnosis of the case was confirmed through multiple microbiologic and molecular techniques. To enhance the epidemiological analysis, we conducted several molecular genotyping procedures, including multi-locus sequence typing, SNP-profiling, and whole genome sequence typing. Each technique has different molecular epidemiologic advantages, all of which provided evidence that the infecting strain was most similar to those found in Southeast Asia, possibly originating in, or around, Malaysia. Advancements in new typing technologies provide genotyping resolution not previously available to public health investigators, allowing for more accurate source identification

A model of online protection to reduce children's online risk exposure: empirical evidence from Asia

Children are surrounded by a variety of digital media and are exposed to potential risks that come with such easy accessibility. Learning how to be safe online is an important consideration for both children and their caregivers. The present study proposes an integrated model of online safety based on constructs from protection motivation theory and the health belief model, namely perceived severity of (and susceptibility to) risk, online self-efficacy, online privacy concern, and digital literacy. The study comprised a survey conducted among 420 schoolchildren aged 9–16 years. Using partial least squares-structural equation modelling, the results illustrated the presence of a negative effect of ‘perceived severity of online risk’ toward online risks, whereas the effect of ‘digital literacy’ was found to be positive. Children whose perception of online risks was more severe were less exposed to online risks if they had higher ‘online privacy concerns’ than the children with higher ‘digital literacy’ who are more exposed to online risk. Results of the study show that engaging in safe online behaviour requires children to have a high perception regarding severity of online risks as well as knowledge of online privacy concerns. Online risks and opportunities occur in parallel. Consequently, the factors that increase or decrease risk may also increase or decrease the benefits

Leiomodin-3 dysfunction results in thin filament disorganization and nemaline myopathy

Peer reviewe