1,159 research outputs found

    The Linear-Size Evolution of Classical Double Radio Sources

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    Recent investigations of how the median size of extragalactic radio sources change with redshift have produced inconsistent results. Eales compared the radio and optical properties of a bright 3C and faint 6C sample and concluded that D(1+z)1.1±0.5D\propto(1+z)^{-1.1\pm0.5} (Ω0=0\Omega_0 = 0), with DD being the median size of the radio sources at a given epoch and z the redshift. Oort, Katgert, and Windhorst, on the other hand, from a comparison of the properties of a number of radio samples, found much stronger evolution, with D(1+z)3.3±0.5D\propto(1+z)^{-3.3 \pm0.5}. In this paper we attempt to resolve the difference. We have repeated the analysis of Eales using the virtually complete redshift information that now exists for the 6C sample. Confining our analysis to FR2 sources, which we argue is the best-understood class of radio sources and the least likely to be affected by selection effects, we find D(1+z)1.2±0.5D\propto(1+z)^{-1.2\pm0.5} (Ω0=0\Omega_0 = 0) and D(1+z)1.7±0.4D\propto(1+z)^{-1.7\pm0.4} (Ω0=1\Omega_0 = 1). Our complete redshift information allows us to gain insight into our result by plotting a radio luminosity-size (P-D) diagram for the 6C sample. The most obvious difference between the 3C and 6C P-D diagrams is the clump of sources in the 6C diagram at D100kpc,P1515x1027WHz1sr1D\sim 100 kpc, P_{151}\sim 5x10^{27} WHz^{-1}sr^{-1}. These clump sources have similar sizes to the emission-line regions found around high-redshift radio galaxies, suggesting that the presence of dense line-emitting gas around high-redshift radio galaxies is responsible for the size evolution. We show that this explanation can quantitatively explain the observed size evolution, as long as there is either little X-ray emitting gas around these objects or, if there is, it is distributed in a similar way to the emission-line gas: highly anisotropic and inhomogeneous.Comment: compressed and uuencoded postscript file. 33 pages including 5 figures (441951 bytes). Accepted for publication in September Ap

    Impacts of the Primary School Free Breakfast Initiative on socio-economic inequalities in breakfast consumption among 9–11-year-old schoolchildren in Wales

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    Objectives - Universal interventions may widen or narrow inequalities if disproportionately effective among higher or lower socio-economic groups. The present paper examines impacts of the Primary School Free Breakfast Initiative in Wales on inequalities in children's dietary behaviours and cognitive functioning.<p></p> Design Cluster - randomised controlled trial. Responses were linked to free school meal (FSM) entitlement via the Secure Anonymised Information Linkage databank. Impacts on inequalities were evaluated using weighted school-level regression models with interaction terms for intervention × whole-school percentage FSM entitlement and intervention × aggregated individual FSM entitlement. Individual-level regression models included interaction terms for intervention × individual FSM entitlement.<p></p> Setting - Fifty-five intervention and fifty-six wait-list control primary schools.<p></p> Subjects - Approximately 4500 children completed measures of dietary behaviours and cognitive tests at baseline and 12-month follow-up.<p></p> Results School-level models indicated that children in intervention schools ate a greater number of healthy items for breakfast than children in control schools (b = 0·25; 95 % CI 0·07, 0·44), with larger increases observed in more deprived schools (interaction term b = 1·76; 95 % CI 0·36, 3·16). An interaction between intervention and household-level deprivation was not significant. Despite no main effects on breakfast skipping, a significant interaction was observed, indicating declines in breakfast skipping in more deprived schools (interaction term b = −0·07; 95 % CI −0·15, −0·00) and households (OR = 0·67; 95 % CI 0·46, 0·98). No significant influence on inequality was observed for the remaining outcomes.<p></p> Conclusions - Universal breakfast provision may reduce socio-economic inequalities in consumption of healthy breakfast items and breakfast skipping. There was no evidence of intervention-generated inequalities in any outcomes

    Connecting the Milky Way potential profile to the orbital timescales and spatial structure of the Sagittarius Stream

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    Recent maps of the halo using RR Lyrae from Pan-STARRS1 have clearly depicted the spatial structure of the Sagittarius stream. These maps show the leading and trailing stream apocenters differ in galactocentric radius by a factor of two, and also resolve substructure in the stream at these apocenters. Here we present dynamical models that reproduce these features of the stream in simple Galactic potentials. We find that debris at the apocenters must be dynamically young, in the sense of being stripped off in the last two pericentric passages, while the Sagittarius dwarf is currently experiencing a third passage. The ratio of apocenters is sensitive to both dynamical friction and the outer slope of the Galactic rotation curve. These dependences can be understood with simple regularities connecting the apocentric radii, circular velocities, and orbital period of the progenitor. The effect of dynamical friction on the stream can be constrained using substructure within the leading apocenter. Our ensembles of models are not intended as statistically proper fits to the stream. Nevertheless, out of the range of models we consider, we consistently find the mass within 100 kpc to be 7×1011M\sim 7 \times 10^{11} \, M_{\odot}, with a nearly flat rotation curve between 50 and 100 kpc. This points to a more extended Galactic halo than assumed in some current models. As in previous work, we find prolate or triaxial halos ease agreement with the track of the leading stream. We display the behavior of our models in various observational spaces and characterize the substructure expected within the stream. In particular, the young trailing stream visible near trailing apocenter should exhibit a tight trend of velocity with distance separate from the older debris, and we suggest that this will serve as an especially useful probe of the outer Galactic potential.Comment: Submitted to MNRA

    Porcine Models of Pancreatic Cancer: Current Status and Future

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    The KRASG12D and TP53R172H mutations are the leading causes of pancreatic cancer, with the third deadliest cancer mortality rate. Majority of the pancreatic cancer research utilizes mouse models. Our lab is currently studying porcine as a suitable model to study pancreatic cancer due to the comparative anatomy and genomic similarities between humans and porcine. Our first approach to develop the porcine pancreatic cancer model was to orthotopically implant the transformed and mutated primary pig pancreatic epithelial cells into the pig pancreas. The second approach was using the Oncopig model with KRASG12D and TP53R172H genetic mutations. The mutated genes were expressed by injecting adenovirus with Cre recombinase to develop tumors. Hematoxylin and Eosin staining, immunohistochemistry, plasmid, and RNA isolation were used to study the porcine pancreas before and after the tumor induction. Results showed that humans and porcine have similar histological characteristics showing comprising islets, ducts, and acinar cells. For the orthotopic model, after two weeks of orthotopic implantation, there were signs of pancreatitis and some evidence of tumor-like cells, but not tumors. Some signs were the formation of acinar to ductal metaplasia, massive immune cell responses, and vimentin expression in the regions of desmoplasia. Our results showed that the Oncopigs did generate pancreatic tumors successfully and are currently being characterized for future use, and the orthotopic model showed promising results. However, implanted tumor cells will be given additional help to allow them to survive from host immune response by over-expressing PD-L1 on the implanted tumor cells surface.https://digitalcommons.unmc.edu/surp2022/1041/thumbnail.jp

    The Influence of Strontium Substitution in Fluorapatite Glasses and Glass-Ceramics

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    Strontium is often substituted for calcium in order to confer radio-opacity in glasses used for dental cements, Biocomposites and bio glass-ceramics. The present paper investigates the influence of substituting strontium for calcium in a glass of the following composition: 4.5SiO23Al2O 31.5P2O53CaO2CaF2, having a Ca:P ratio of 1.67 corresponding to calcium fluorapatite (Ca5(PO 4)3F). The glasses were characterized by magic angle spinning nuclear magnetic resonance (MAS-NMR), by differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD). The 29Si, 27Al and 31P NMR spectra for the glasses with different strontium contents were identical. The 19F spectra indicated the presence of F-Ca(n) and Al-F-Ca(n) species in the calcium glasses and in the strontium glasses F-Sr(n) and Al-F-Sr(n). It can be concluded that strontium substitutes for calcium with little change in the glass structure as a result of their similar charge to size ratio. The low strontium glasses bulk nucleated to a calcium apatite phase. Intermediate strontium content glasses surface nucleated to a mixed calcium-strontium apatite and the fully strontium substituted glass to strontium fluorapatite. © 2004 Elsevier B.V. All rights reserved

    Primary structure and comparative sequence-analysis of an insect apolipoprotein: apolipophorin-Iii from Manduca-sexta

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    The amino acid sequence of an insect apolipoprotein, apolipophorin-III from Manduca sexta, was determined by a combination of cDNA and protein sequencing. The mature hemolymph protein consists of 166 amino acids. The cDNA also encodes for an amino-terminal extension of 23 amino acids which is not represented in the mature hemolymph protein. The existence of a precursor protein was confirmed by in vitro translation of fat body mRNA. Computer-assisted comparative sequence analysis revealed the following points: 1) the protein is composed of tandemly repeating tetradecapeptide units with a high potential for forming amphiphilic helical structures. Compared to mammalian apolipoproteins the repeat units in the insect apolipoprotein show considerable length variability; 2) the sequence has a striking resemblance to several human apolipoproteins including apoE, AIV, AI, and CI. However, the homology seems to be entirely functional since, although the insect and mammalian apoproteins contain very similar types of amino acid residues, the actual degree of sequence identity is quite low. Whether the mammalian and insect apoproteins are derived from a common ancestral amphiphilic helix forming, lipid-binding protein, or arose by convergent evolution can not be determined at present. This represents the first complete amino acid sequence for an insect apolipoprotein

    Calculating energy levels of isomerizing tetra-atomic molecules. I. The rovibrational bound states of Ar2HF

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    A general, six-dimensional computational method for the accurate calculation of rotationally and vibrationally excited states of tetra-atomic molecules is developed. The resulting program is particularly appropriate for molecules executing wide-amplitude motions and isomerizations. An application to the Ar2HF van der Waals trimer is presented in which the HF intramolecular stretching coordinate is separated out adiabatically and is not treated explicitly. Vibrational term values up to about 100 cm−1 with absolute convergence to better than 0.1 cm−1 are reported. These calculations employ more extensive vibrational basis sets and hence consider a much higher density of states than hitherto. States that sample Ar–Ar–HF linear configurations and approach Ar–HF–Ar linear configurations are characterized for the first time. Results for total angular momentumJ=0 and 1 provide the first accurate calculations of rotational constants for this system. The rotational constants for the HF bending states of Ar2HF in the ground and first vibrationally excited states of the HF monomer are in good agreement with experiment, confirming the accuracy of the potential used in this work

    A Trust for Whom?: Managing Colorado\u27s 3 Million Acres of State Land

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    14 pages. Includes biographical information for John M. Evans, Reeves Brown, and Mark A. E. Burget. State Land Board Commissioner Maxine Stewart was also a speaker for this program, but did not submit any written materials. Contents: A trust for whom? managing Colorado\u27s 3 million acres of state land : a critique of the constitutional amendment / prepared by John Evans -- A cattlemen\u27s [sic] perspective of state land management / presented by Reeves Brown -- Remarks outline / Mark A. E. Burget Program was presented on Monday, February 5, 1996 at the offices of Holland & Hart in Denver, Colo. Historically, state trust lands have been managed for public schools revenue. Now there is pressure to protect some state lands as open space. Should trust lands be managed for broader public values? Is this consistent with existing legal mandates? Speakers: State Land Board Commissioner Maxine Stewart; John Evans, Colorado Board of Education; Reeves Brown, Colorado Cattlemen\u27s Association; The Nature Conservancy\u27s Colorado State Director Mark Burget. Special focus on the recently implemented Multiple Use Program and also on how The Nature Conservancy is working with the State Land Board to preserve resources. Center Director Elizabeth Rieke will moderate

    Counting the cost: estimating the number of deaths among recently released prisoners in Australia

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    Objective: To estimate the number of deaths among people released from prison in Australia in the 2007–08 financial year, within 4 weeks and 1 year of release. Design, participants and setting: Application of crude mortality rates for ex-prisoners (obtained from two independent, state-based record-linkage studies [New South Wales and Western Australia]) to a national estimate of the number and characteristics of people released from prison in 2007–08. Main outcome measures: Estimated number of deaths among adults released from Australian prisons in 2007–08, within 4 weeks and 1 year of release, classified by age, sex, Indigenous status and cause of death. Results: It was estimated that among people released from prison in 2007–08, between 449 (95% CI, 380–527) and 472 (95% CI, 438–507) died within 1 year of release. Of these, between 68 (95% CI, 56–82) and 138 (95% CI, 101–183) died within 4 weeks of release. Most of these deaths were not drug-related. Conclusion: The estimated annual number of deaths among recently released prisoners in Australia is considerably greater than the annual number of deaths in custody, highlighting the extreme vulnerability of this population on return to the community. There is an urgent need to establish a national system for routine monitoring of ex-prisoner mortality and to continue the duty of care beyond the prison walls
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