Goitre Survey, Omay Tribal Trust Lands, Kariba District, Rhodesia

A CAJM article on the population of people affected by goiter in the country.There is very little published information about goitre in Southern Rhodesia (Kelly and Sneddon, 1960; Dent and Strover, 1966), and of that available much is not quantitative and impressions rather than figures have been recorded. This survey was undertaken on behalf of the Department of Surgery, University College of Rhodesia, in conjunction with a leprosy survey of the same area, to obtain quantitative data on the incidence of goitre in the region

Recoiling Black Holes in Quasars

Recent simulations of merging black holes with spin give recoil velocities from gravitational radiation up to several thousand km/s. A recoiling supermassive black hole can retain the inner part of its accretion disk, providing fuel for a continuing QSO phase lasting millions of years as the hole moves away from the galactic nucleus. One possible observational manifestation of a recoiling accretion disk is in QSO emission lines shifted in velocity from the host galaxy. We have examined QSOs from the Sloan Digital Sky Survey with broad emission lines substantially shifted relative to the narrow lines. We find no convincing evidence for recoiling black holes carrying accretion disks. We place an upper limit on the incidence of recoiling black holes in QSOs of 4% for kicks greater than 500 km/s and 0.35% for kicks greater than 1000 km/s line-of-sight velocity.Comment: 4 pages, 4 figures, uses emulateapj, Submitted to ApJ Letter

Average symptom trajectories following incident radiographic knee osteoarthritis: data from the Osteoarthritis Initiative

Introduction Previous research has identified the existence of a prodromal phase of symptom worsening beginning on average 2–3 years prior to the first appearance of radiographic knee osteoarthritis (OA). The current study extends these observations to investigate the trajectory of self-reported pain, stiffness, function and other symptoms following the incidence of radiographic OA. Methods Data were from the incidence cohort of the Osteoarthritis Initiative public use data sets. Cases were defined as knees without symptoms at enrolment, which developed incident radiographic OA (Kellgren and Lawrence grade ≥2) at any of the first 4 annual follow-up visits. Symptoms investigated were knee-specific Western Ontario & McMaster Universities Osteoarthritis Index and Knee injury and Osteoarthritis Outcome Score subscale scores and individual items, available up to 3 years before and 5 years after the incidence of radiographic OA. Trajectories of having at least one of the symptoms from a subscale, and for each individual symptom over time, were fitted using multilevel logistic regression models. Results The probability of symptoms following the initial prodromal phase generally stabilised, whereas the probability of moderate, severe or extreme symptoms was consistently low. Two exceptions were pain frequency, which increased greatly in the lead up to incidence, then decreased slightly, and audible joint sounds, which had a much higher overall probability, and after increasing prior to incident radiographic OA, stabilised then started to increase again at 5 years. Conclusions Following an increase in the risk of symptoms during the prodromal phase, this risk does not continue to increase in the period up to 5 years after the incidence of radiographic OA

The Yang Lee Edge Singularity on Feynman Diagrams

We investigate the Yang-Lee edge singularity on non-planar random graphs, which we consider as the Feynman Diagrams of various d=0 field theories, in order to determine the value of the edge exponent. We consider the hard dimer model on phi3 and phi4 random graphs to test the universality of the exponent with respect to coordination number, and the Ising model in an external field to test its temperature independence. The results here for generic (``thin'') random graphs provide an interesting counterpoint to the discussion by Staudacher of these models on planar random graphs.Comment: LaTeX, 6 pages + 3 figure

A Potts/Ising Correspondence on Thin Graphs

We note that it is possible to construct a bond vertex model that displays q-state Potts criticality on an ensemble of phi3 random graphs of arbitrary topology, which we denote as ``thin'' random graphs in contrast to the fat graphs of the planar diagram expansion. Since the four vertex model in question also serves to describe the critical behaviour of the Ising model in field, the formulation reveals an isomorphism between the Potts and Ising models on thin random graphs. On planar graphs a similar correspondence is present only for q=1, the value associated with percolation.Comment: 6 pages, 5 figure

Gender-specific selection on codon usage in plant genomes

<p>Abstract</p> <p>Background</p> <p>Currently, there is little data available regarding the role of gender-specific gene expression on synonymous codon usage (translational selection) in most organisms, and particularly plants. Using gender-specific EST libraries (with > 4000 ESTs) from <it>Zea mays </it>and <it>Triticum aestivum</it>, we assessed whether gender-specific gene expression <it>per se </it>and gender-specific gene expression level are associated with selection on codon usage.</p> <p>Results</p> <p>We found clear evidence of a greater bias in codon usage for genes expressed in female than in male organs and gametes, based on the variation in GC content at third codon positions and the frequency of species-preferred codons. This finding holds true for both highly and for lowly expressed genes. In addition, we found that highly expressed genes have greater codon bias than lowly expressed genes for both female- and male-specific genes. Moreover, in both species, genes with female-specific expression show a greater usage of species-specific preferred codons for each of the 18 amino acids having synonymous codons. A supplemental analysis of <it>Brassica napus </it>suggests that bias in codon usage could also be higher in genes expressed in male gametophytic tissues than in heterogeneous (flower) tissues.</p> <p>Conclusion</p> <p>This study reports gender-specific bias in codon usage in plants. The findings reported here, based on the analysis of 1 497 876 codons, are not caused either by differences in the biological functions of the genes or by differences in protein lengths, nor are they likely attributable to mutational bias. The data are best explained by gender-specific translational selection. Plausible explanations for these findings and the relevance to these and other organisms are discussed.</p

Type 2 Active Galactic Nuclei with Double-Peaked [OIII] Lines. II. Single AGNs with Complex Narrow-Line Region Kinematics are More Common than Binary AGNs

(Abridged) Approximately 1% of low redshift (z<0.3) optically-selected type 2 AGNs show a double-peaked [OIII] narrow emission line profile in their spatially-integrated spectra. Such features are usually interpreted as due either to kinematics, such as biconical outflows and/or disk rotation of the narrow line region (NLR) around single black holes, or to the relative motion of two distinct NLRs in a merging pair of AGNs. Here we report follow-up near infrared (NIR) imaging and optical slit spectroscopy of 31 double-peaked [OIII] type 2 AGNs drawn from the SDSS parent sample presented in Liu et al (2010). These data reveal a mixture of origins for the double-peaked feature. Roughly 10% of our objects are best explained by binary AGNs at (projected) kpc-scale separations, where two stellar components with spatially coincident NLRs are seen. ~ 50% of our objects have [OIII] emission offset by a few kpc, corresponding to the two velocity components seen in the SDSS spectra, but there are no corresponding double stellar components seen in the NIR imaging. For those objects with sufficiently high quality slit spectra, we see velocity and/or velocity dispersion gradients in [OIII] emission, suggestive of the kinematic signatures of a single NLR. The remaining ~40% of our objects are ambiguous, and will need higher spatial resolution observations to distinguish between the two scenarios. Our observations therefore favor the kinematics scenario with a single AGN for the majority of these double-peaked [OIII] type 2 AGNs. We emphasize the importance of combining imaging and slit spectroscopy in identifying kpc binary AGNs, i.e., in no cases does one of these alone allow an unambiguous identification. We estimate that ~ 0.5-2.5% of the z<0.3 type 2 AGNs are kpc-scale binary AGNs of comparable luminosities, with a relative orbital velocity >~150 km/s.Comment: Minor changes; ApJ in press; 71 pages with 40 figures; color print preferred; a high-resolution version can be downloaded at https://www.cfa.harvard.edu/~yshen/papers/double_o3_rv1.pd