1,798 research outputs found
A complete quasar sample at intermediate redshift
No full textA search for intermediate-redshift quasars has been carried out with slitless spectroscopy in the central 21.07 sq deg of the SA 94, where the existence of a large database of objects for which slit spectroscopy was already available provided a valuable opportunity of testing the properties of the present selection technique. Fifty candidates have been observed with slit spectroscopy, confirming 34 quasars and two H II galaxies. The completeness of this survey as a function of magnitude and redshift has been analyzed, and an effective area of 16.9 sq deg has been evaluated. The estimated quasar surface density for QSOs with z between 1.8 and 3.2 and B less than 19.4 is 1.4 + or - 0.3/sq deg, in agreement with other surveys in the literature
The Clowes-Campusano large quasar group survey. I.Galexselected sample of lyman Break Galaxies ATz∼ 1
No full textThe Clowes & Campusano Large Quasar Group (LQG, MNRAS 1991, 249, 218) at z = 1.28 has been re-examined using the quasar data from the DR5QSO catalog of the Sloan Digital Sky Survey. In the 1991 discovery, the LQG impinged on the northern, southern and eastern limits of the survey. In the DR5QSO data, the western, northern and southern boundaries of the LQG remain essentially unchanged, but an extension eastwards of 2 deg. is indicated. In the DR5QSO data, the LQG has 31 members, with z = 1.27, and a characteristic size 250 Mpc. Its quasar density contrast is δρ/ρ 0.94, suggesting either that it is approaching the non-linear regime or that quasar formation is substantially enhanced in LQGs. A new LQG of 41 members is indicated at z = 1.11 and within 0.8 deg. of the Clowes & Campusano LQG. A further LQG, at z = 1.53 and within 1.5 deg. of the Clowes & Campusano LQG, was previously known but is found here with membership increased to 20. The characteristic sizes and quasar density contrasts of these two additional LQGs are (325 Mpc, 0.42) and (200 Mpc, 0.66) respectively. This concentration of three LQGs in the same cosmological neighborhood, with centroids that are almost co-linear, raises the possibility that large-scale structure can itself be associated on scales 350 Mpc
Meeting with the Hebrew author Elias Hurwitz
No full textWhite paper; handpainted; on the reverse of Luftwaffe uniform pattern. Digitized posters are related to the activities of Jewish displaced persons drawn from the Records of Displaced Persons Camps and Centers in Germany (RG 294.2) Italy (RG 294.3) and Austria (RG 294.4) held by YIVO Archives. Please consult the historical note for those record groups for further information.Digital ImageDigital finding aid available
Obituary announcement about author and labor activist Sh. Mendelson
No full textBrown paper; handpainted. Digitized posters are related to the activities of Jewish displaced persons drawn from the Records of Displaced Persons Camps and Centers in Germany (RG 294.2) Italy (RG 294.3) and Austria (RG 294.4) held by YIVO Archives. Please consult the historical note for those record groups for further information.Digital ImageDigital finding aid available
Two close large quasar groups of size ∼ 350 Mpc at
No full textThe Clowes & Campusano large quasar group (LQG) at inline image has been re-examined using the quasar data from the DR7QSO catalogue of the Sloan Digital Sky Survey. In the 1991 discovery, the LQG impinged on the northern, southern and eastern limits of the survey. In the DR7QSO data, the western, northern and southern boundaries of the LQG remain essentially the same, but an extension eastwards of ∼2° is indicated. In the DR7QSO data, the LQG has 34 members, with inline image. A new group of 38 members is indicated at inline image and within ∼2bsl000640 of the Clowes & Campusano LQG. The characteristic sizes of these two LQGs, ∼350–400 Mpc, appear to be only marginally consistent with the scale of homogeneity in the concordance cosmology. In addition to their intrinsic interest, these two LQGs provide locations in which to investigate early large-scale structure in galaxies and to identify high-z clusters. A method is presented for assessing the statistical significance and overdensity of groups found by linkage of points
Sweeping has no effect on renormalized turbulent viscosity
No full textWe perform renormalization group analysis (RG) of the Navier-Stokes equation in the presence of constant mean velocity field , and show that the renormalized viscosity is unaffected by , thus negating the ``sweeping effect", proposed by Kraichnan [Phys. Fluids {\bf 7}, 1723 (1964)] using random Galilean invariance. Using direct numerical simulation, we show that the correlation functions for and differ from each other, but the renormalized viscosity for the two cases are the same. Our numerical results are consistent with the RG calculations
BONDING AND DYNAMICS OF CNRg AND CRg COMPLEXES
No full textAuthor Institution: Department of Chemistry, Emory University, Atlanta, GA 30322The van der Waals complexes of CN and C with rare gas atoms (Rg) are of interest from the perspectives of their bonding characteristics and predissociation dynamics. Matrix isolation data indicate that that the bonding ranges from a weak van der Waals interaction for the Ne complexes to incipient chemical bonding for Xe. The low-lying vibronic states of CN and C are interleaved, which facilitates electronic energy transfer. Consequently, electronic predissociation of CNRg and CRg complexes provides a useful means to examine the detailed dynamics of electronic energy transfer. Predissociation processes for CNRg complexes have been characterized using double resonance techniques. The final state distributions exhibit symmetry preferences that yield insights concerning the topologies of the relevant potential energy surfaces. In addition, bond energies can be deduced from the predissociation dynamics. Data for the binary complexes CNRg (Rg=Ne, Ar, Kr, and Xe) and CRg will be presented, along with theoretical analyses based on potential energy surfaces
René Géronimo Favaloro : pioneer of Cardiac Surgery
No full textDr. René G. Favaloro moved to the Cleveland Clinic in 1962 and proceeded to reshape the face of cardiac surgery as we knew it. Together with his colleagues at the Cleveland Clinic, Drs. Effler, Sones, Proudfit, Groves, Sheldon and countless others, he contributed to the double internal mammary arterymyocardial implantation by the Vineberg method, and by May 1967, he reconstructed the right coronary artery by the saphenous vein graft interposition. These landmark procedures paved the way for the aorto-coronary saphenous vein bypass graft in October 1967. Many similar breakthroughs ensued, with the application of the bypass technique to the left coronary artery, the combination of coronary artery bypass graft with left ventricular reconstruction and valve repair/replacement and finally, by December, a double bypass to the right coronary artery and anterior descending branch of the left coronary artery. In June, 1971, Dr. Favaloro decided to leave the Cleveland Clinic and return to Argentina where he created a medical centre, a teaching unit, a research department and finally an Institute of Cardiology and Cardiovascular Surgery. This was his greatest personal ambition. Over and above his brilliant mind and craft, Dr. Favaloro was a man of integrity, courage, honesty and humility, whose name will never cease to reverberate throughout the history of medicine.peer-reviewe
Relation of radio-quiet quasars to galaxy clusters z<0.3
No full textWe investigate whether radio-quiet quasars (RQQs) with z < 0.3 (and predominantly of low luminosity) are located preferentially in specific regions with respect to the centres and boundaries of neighbouring galaxy clusters. This way of characterizing the environment of RQQs differs from previous studies, which relied on the galaxy excess statistics within small radii around the quasars. For the detection of galaxy clusters we use a robust, semiparametric method based on a maximum likelihood estimate applied to Voronoi tessellation and enhanced by a colour-cut approach, allowing boundary determination and redshift estimates. We find that most of the RQQs reside within 3 h -1 Mpc of the centre of a galaxy cluster with comparable redshift and that none of them lies in the core itself. About 20 per cent of the investigated quasars reside between two galaxy clusters, which are possibly at an early stage of merger. Consequently, we suggest that quasars found in rich environments are associated with cluster mergers whereas those found in poorer environments are associated with infall towards a cluster. The information on larger scales provided by our analysis thus allows a clearer interpretation of the diverse environments that have for many years been reported in the literature for smaller scales. We discuss our findings in the context of existing quasar formation models and suggest that at least two formation mechanisms coexist. Additionally, we confirm, using multiple data sets, that low-redshift quasars follow a narrow channel of width ∼10 h -1 Mpc around the large-scale structure (LSS) traced by galaxy clusters, in agreement with the first report of this effect by Söchting, Clowes and Campusano. Such a result, if it applies to quasars at higher redshifts, has the potential to explain the clustering of quasars on scales <10 h -1 Mpc found initially by Shanks et al. The association of the LSS in clusters with the spatial distribution of quasars is not reproduced by samples of narrow emission-line galaxies (NELGs), indicating that the occurrence of NELGs does not require the same environmental conditions as that of quasars
A non-classical synthetic strategy for organic mesocrystals
No full textMesocrystals are ordered nanoparticle superstructures, often with internal porosity, which receive much recent research interest in catalysis, energy storage, sensors, and biomedicine area. Understanding the mechanism of synthetic routes is essential for precise control of size and structure that affect the function of mesocrystals. The classical synthetic strategy of mesocrystal was formed via self-assembly of nanoparticles with a faceted inorganic core but a denser (or thicker) shell of organic molecules. However, the potential materials and synthetic handles still need to be explored to meet new applications. In this work, we develop a non-classical synthetic strategy for organic molecules, such as tetrakis (4-hydroxyphenyl) ethylene (TPE-4OH), tetrakis (4-bromophenyl) ethylene (TPE-4Br), and benzopinacole, to produce mesocrystals with composed of microrod arrays via co-solvent-induced crystal transformation. The aligned nanorods are grown epitaxially onto organic microplates, directed by small lattice mismatch between plates and rods. Thus, the present work offers general synthetic handle for establishing well-organized organic mesocrystals.Ministry of Education (MOE)Published versionThe author(s) declare that financial support was received for the research, authorship, and/or publication of this article. This work was supported by the MOE of Singapore (RG 14/13 and RG 5/16), the National Natural Science Foundation of China (No. 21673117), recruitment Program of Global Experts, Jiangsu Provincial Foundation for Specially-Appointed Professor, start-up fund at Nanjing Tech University (39837102), SICAM Fellowship from Jiangsu National Synergetic Innovation Center for Advanced Materials, and Jiangsu Science and Technology Plan (Project No. BK20211258)
- …
