A Common Origin for Quasar Extended Emission-Line Regions and Their Broad-Line Regions

We present a correlation between the presence of luminous extended emission-line regions (EELRs) and the metallicity of the broad-line regions (BLRs) of low-redshift quasars. The result is based on ground-based [O III] 5007 narrow-band imaging and Hubble Space Telescope UV spectra of 12 quasars at 0.20 < z < 0.45. Quasars showing luminous EELRs have low-metallicity BLRs (Z < 0.6 Z_Solar), while the remaining quasars show typical metal-rich gas (Z > Z_Solar). Previous studies have shown that EELRs themselves also have low metallicities (Z < 0.5 Z_Solar). The correlation between the occurrence of EELRs and the metallicity of the BLRs, strengthened by the sub-Solar metallicity in both regions, indicates a common external origin for the gas, almost certainly from the merger of a gas-rich galaxy. Our results provide the first direct observational evidence that the gas from a merger can indeed be driven down to the immediate vicinity (< 1 pc) of the central black hole.Comment: Accepted for publication in ApJ Letters. 4 pages, 1 figure, 1 tabl

Searching for intrinsic charm in the proton at the LHC

Despite rather long-term theoretical and experimental studies, the hypothesis of the non-zero intrinsic (or valence-like) heavy quark component of the proton distribution functions has not yet been confirmed or rejected. The LHC with $pp$-collisions at $\sqrt{s}=$ 7--14 TeV will obviously supply extra unique information concerning the above-mentioned component of the proton. To use the LHC potential, first of all, one should select the parton-level (sub)processes (and final-state signatures) that are most sensitive to the intrinsic heavy quark contributions. To this end inclusive production of $c(b)$-jets accompanied by photons is considered. On the basis of the performed theoretical study it is demonstrated that the investigation of the intrinsic heavy quark contributions looks very promising at the LHC in processes such as $pp\rightarrow \gamma+ c(b)+X$.Comment: 13 pages, 6 figure

Compressive Raman imaging with spatial frequency modulated illumination

We report a line scanning imaging modality of compressive Raman technology with spatial frequency modulated illumination using a single pixel detector. We demonstrate the imaging and classification of three different chemical species at line scan rates of 40 Hz

Bayesian estimation for selective trace gas detection

We present a Bayesian estimation analysis for a particular trace gas detection technique with species separation provided by differential diffusion. The proposed method collects a sample containing multiple gas species into a common volume, and then allows it to diffuse across a linear array of optical absorption detectors, using, for example, high-finesse Fabry-Perot cavities. The estimation procedure assumes that all gas parameters (e.g. diffusion constants, optical cross sections) are known except for the number population of each species, which are determined from the time-of-flight absorption profiles in each detector

Samuelson´s full duality and the use of directed acyclical graphs

To date, mixed demand systems have been all but ignored in empirical work. A possible reason for the scarcity of such applications is that one needs to know a priori which prices and quantities are endogenous in the mixed demand system. By using a directed acyclical graph (DAG), causal relationships among price and quantity variables are identified giving rise to a causally identified mixed demand system. A statistical comparison is made of the traditional Rotterdam model, a synthetic demand system, which subsumes the traditional Rotterdam model, and a Rotterdam mixed demand system identified through the use of a DAG. In this analysis, the respective demand systems consist of five products: steak, ground beef, beef roasts, pork, and chicken.directed acyclic graphs, mixed demand systems

High-Resolution K' Imaging of the z = 1.786 Radio Galaxy 3C 294

We have obtained imaging in the K' band (~I-band rest frame) of the z=1.786 radio galaxy 3C 294 with the 36-element curvature-sensing adaptive optics system Hokupa`a and the Canada-France-Hawaii Telescope. At a resolution of < \~0."15, the galaxy is seen as a group of small but resolved knots distributed over a roughly triangular region ~1."4 across. The interpretation of the structure depends on the location of the nucleus, as indicated by the compact radio core. Its position is uncertain by > ~0."5 (2-sigma) because of uncertainties in the optical astrometry, but our best estimate places it at or near the southern apex of the distribution. If this location is correct, the most likely interpretation is that of a hidden quasar nucleus illuminating dusty infalling dwarf-galaxy-like clumps having characteristic sizes of ~1.5 kpc.Comment: 8 pages. One figure in gif format. Postscript version including fig. (240 kb) available at http://www.ifa.hawaii.edu/~canaguby/preprints.html To appear in ApJ. Letter

Is the Scottish population living dangerously? Prevalence of multiple risk factors: the Scottish Health Survey 2003

&lt;b&gt;Background:&lt;/b&gt; Risk factors are often considered individually, we aimed to investigate the prevalence of combinations of multiple behavioural risk factors and their association with socioeconomic determinants.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Methods:&lt;/b&gt; Multinomial logistic regression was used to model the associations between socioeconomic factors and multiple risk factors from data in the Scottish Health Survey 2003. Prevalence of five main behavioural risk factors - smoking alcohol, diet, overweight/obesity, and physical inactivity, and the odds in relation to demographic, individual and area socioeconomic factors.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Results:&lt;/b&gt; Full data were available on 6,574 subjects (80.7% of the survey sample). Nearly the whole adult population (97.5%) reported to have at least one behavioural risk factor; while 55% have three or more risk factors; and nearly 20% have four or all five risk factors. The most important determinants for having four or five multiple risk factors were low educational attainment which conferred around a 3-fold increased odds compared to high education; and residence in the most deprived communities (relative to least deprived) which had greater than 3-fold increased odds.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Conclusions:&lt;/b&gt; The prevalence of multiple behavioural risk factors was high and the prevalence of absence of all risk factors very low. These behavioural patterns were socioeconomically determined. Policy to address factors needs to be joined up and better consider underlying socioeconomic circumstances.&lt;p&gt;&lt;/p&gt