320 research outputs found

    Breaking into the conversation: cultural value and the role of the South African National Arts Festival from apartheid to democracy

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    The paper examines the value of the South African National Arts Festival (NAF) in the transition to democracy using theories of cultural capital. NAF history from 1974 to 2004 is used to argue that the Festival provided an important arena for the expression of political resistance in the 1980s and, to some degree, continues to do so today. It is concluded that an important part of the value of the arts is their ability to provide a forum for debating the goals and values of society and that individualistic utility theory is not always successful in measuring such social value

    The genetic contribution of the NO system at the glutamatergic post-synapse to schizophrenia : further evidence and meta-analysis

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    NO is a pleiotropic signaling molecule and has an important role in cognition and emotion. In the brain, NO is produced by neuronal nitric oxide synthase (NOS-I, encoded by NOS1) coupled to the NMDA receptor via PDZ. interactions; this protein-protein interaction is disrupted upon binding of NOS1 adapter protein (encoded by NOS1AP) to NOS-I. As both NOS1 and NOS1AP were associated with schizophrenia, we here investigated these genes in greater detail by genotyping new samples and conducting a meta-analysis of our own and published data. In doing so, we confirmed association of both genes with schizophrenia and found evidence for their interaction in increasing risk towards disease. Our strongest finding was the NOS1 promoter SNP rs41279104, yielding an odds ratio of 1.29 in the meta-analysis. As findings from heterologous cell systems have suggested that the risk allele decreases gene expression, we studied the effect of the variant on NOS1 expression in human post-mortem brain samples and found that the risk allele significantly decreases expression of NOS1 in the prefrontal cortex. Bioinformatic analyses suggest that this might be due the replacement of six transcription factor binding sites by two new binding sites as a consequence of proxy SNPs. Taken together, our data argue that genetic variance in NOS1 resulting in lower prefrontal brain expression of this gene contributes to schizophrenia liability, and that NOS1 interacts with NOS1AP in doing so. The NOS1-NOS1AP PDZ interface may thus well constitute a novel target for small molecules in at least some forms of schizophrenia. PostprintPeer reviewe

    Radio Supernova 1987A at 843 MHz

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    We report the flux densities of the evolving radio source SN1987A at 843 MHz measured from observations made with the Molonglo Observatory Synthesis Telescope between 1994 September and 2000 May. The radio light curve shows that the rate of increase of the flux density jumped markedly around days 2800-3000 (i.e. in the first half of 1995), and that since then the radio evolution has been remarkably well fitted by a simple linear increase of (62.7 +- 0.5) microJansky/day. We discuss in detail the relationship between the radio light curve and the recent brightening of the system at optical wavelengths.Comment: To be published in the Astrophysical Journal, 11 pages, 4 postscript figure

    A new search for distant radio galaxies in the Southern hemisphere -- III. Optical spectroscopy and analysis of the MRCR--SUMSS sample

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    We have compiled a sample of 234 ultra-steep-spectrum(USS)-selected radio sources in order to find high-redshift radio galaxies (HzRGs). The sample is in the southern sky at -40 deg < DEC < -30 deg which is the overlap region of the 408-MHz Revised Molonglo Reference Catalogue, 843-MHz Sydney University Molonglo Sky Survey (the MRCR--SUMSS sample) and the 1400-MHz NRAO VLA Sky Survey. This is the third in a series of papers on the MRCR--SUMSS sample. Here we present optical spectra from the ANU 2.3-m telescope, ESO New Technology Telescope and ESO Very Large Telescope for 52 of the identifications from Bryant et al. (2009, Paper II), yielding redshifts for 36 galaxies, 13 of which have z>2. We analyse the K-z distribution and compare 4-arcsec-aperture magnitudes with 64-kpc aperture magnitudes in several surveys from the literature; the MRCR--SUMSS sample is found to be consistent with models for 10^{11}-10^{12} solar mass galaxies. Dispersions about the fits in the K-z plot support passive evolution of radio galaxy hosts since z>3. By comparing USS-selected samples in the literature, we find that the resultant median redshift of the samples shown is not dependent on the flux density distribution or selection frequency of each sample. In addition, our finding that the majority of the radio spectral energy distributions remain straight over a wide frequency range suggests that a k-correction is not responsible for the success of USS-selection in identifying high redshift radio galaxies and therefore the steep radio spectra may be intrinsic to the source or a product of the environment. Two galaxies have been found to have both compact radio structures and strong self-absorption in the Ly-alpha line, suggesting they are surrounded by a dense medium...abridged.Comment: Accepted for MNRAS. 25 page

    Millimetre observations of a sample of high-redshift obscured quasars

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    We present observations at 1.2 mm with MAMBO-II of a sample of z>~2 radio-intermediate obscured quasars, as well as CO observations of two sources with the Plateau de Bure Interferometer. Five out of 21 sources (24%) are detected at a significance of >=3sigma. Stacking all sources leads to a statistical detection of = 0.96+-0.11 mJy and stacking only the non-detections also yields a statistical detection, with = 0.51+-0.13 mJy. This corresponds to a typical far-infrared luminosity L_FIR~4x10^12 Lsol. If the far-infrared luminosity is powered entirely by star-formation, and not by AGN-heated dust, then the characteristic inferred star-formation rate is ~700 Msol yr-1. This far-infrared luminosity implies a dust mass of M_dust~3x10^8 Msol. We estimate that such large dust masses on kpc scales can plausibly cause the obscuration of the quasars. We present dust SEDs for our sample and derive a mean SED for our sample. This mean SED is not well fitted by clumpy torus models, unless additional extinction and far-infrared re-emission due to cool dust are included. There is a hint that the host galaxies of obscured quasars must have higher far-infrared luminosities and cool-dust masses and are therefore often found at an earlier evolutionary phase than those of unobscured quasars. For one source at z=2.767, we detect the CO(3-2) transition, with S_CO Delta nu=630+-50 mJy km s-1, corresponding to L_CO(3-2)= 3.2x10^7 Lsol, or L'_CO(3-2)=2.4x10^10 K km s-1 pc2. For another source at z=4.17, the lack of detection of the CO(4-3) line yields a limit of L'_CO(4-3)<1x10^10 K km s-1 pc2. Molecular gas masses, gas depletion timescales and gas-to-dust ratios are estimated (Abridged).Comment: Accepted by ApJ, 25 pages, 11 figures, 4 table

    Heterogeneity of glycan biomarker clusters as an indicator of recurrence in pancreatic cancer

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    IntroductionOutcomes following tumor resection vary dramatically among patients with pancreatic ductal adenocarcinoma (PDAC). A challenge in defining predictive biomarkers is to discern within the complex tumor tissue the specific subpopulations and relationships that drive recurrence. Multiplexed immunofluorescence is valuable for such studies when supplied with markers of relevant subpopulations and analysis methods to sort out the intra-tumor relationships that are informative of tumor behavior. We hypothesized that the glycan biomarkers CA19-9 and STRA, which detect separate subpopulations of cancer cells, define intra-tumoral features associated with recurrence.MethodsWe probed this question using automated signal thresholding and spatial cluster analysis applied to the immunofluorescence images of the STRA and CA19-9 glycan biomarkers in whole-block sections of PDAC tumors collected from curative resections.ResultsThe tumors (N = 22) displayed extreme diversity between them in the amounts of the glycans and in the levels of spatial clustering, but neither the amounts nor the clusters of the individual and combined glycans associated with recurrence. The combined glycans, however, marked divergent types of spatial clusters, alternatively only STRA, only CA19-9, or both. The co-occurrence of more than one cluster type within a tumor associated significantly with disease recurrence, in contrast to the independent occurrence of each type of cluster. In addition, intra-tumoral regions with heterogeneity in biomarker clusters spatially aligned with pathology-confirmed cancer cells, whereas regions with homogeneous biomarker clusters aligned with various non-cancer cells.ConclusionThus, the STRA and CA19-9 glycans are markers of distinct and co-occurring subpopulations of cancer cells that in combination are associated with recurrence. Furthermore, automated signal thresholding and spatial clustering provides a tool for quantifying intra-tumoral subpopulations that are informative of outcome

    Veterinary students' views on animal patiens and human clients, using Q methodology

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    Veterinarians serve two masters: animal patients and human clients. Both animal patients and human clients have legitimate interests, and conflicting moral claims may flow from these interests. Earlier research concludes that veterinary students are very much aware of the complex and often paradoxical relationship they have and will have with animals. In this article the views of veterinary students about their anticipated relationship with animal patients and human clients are studied. The main part of the article describes discourses of first-year and fourth-year students about their (future) relationship with animals and their caretakers, for which Q-methodology is used. At the end of the article, the discourses are related to the students' gender and their workplace preferences. © 2007 AAVMC

    On the Spectral Index of Distant Radio Galaxies

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    The problems of using the spectral index of radio galaxies in various tests, in particular, in selecting distant radio sources are considered. The history of the question of choosing a criterion of searching for distant radio galaxies based on the spectral index is presented. For a new catalog of 2442 radio galaxies constructed from NED, SDSS, and CATS data, an analytical form of the sp ectral index.redshift relation has been determined for the first time. The spectral index.angular size and spectral index.flux density diagrams have also been constructed. Peculiarities of the distribution of sources on these diagrams are discussed.Comment: 7 pages,5 figure
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