117 research outputs found

    High-resolution X-ray spectroscopy and imaging of the nuclear outflow of the starburst galaxy NGC 253

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    Aims: Using XMM-Newton data, we have aimed to study the nuclear outflow of the nearby starburst galaxy NGC 253 in X-rays with respect to its morphology and to spectral variations along the outflow. Methods: We analysed XMM-Newton RGS spectra, RGS brightness profiles in cross-dispersion direction, narrow band RGS and EPIC images and EPIC PN brightness profiles of the nuclear region and of the outflow of NGC 253. Results: We detect a diversity of emission lines along the outflow of NGC 253. This includes the He-like ions of Si, Mg, Ne and O and their corresponding ions in the next higher ionisation state. Additionally transitions from Fe XVII and Fe XVIII are prominent. The derived temperatures from line ratios along the outflow range from 0.21+/-0.01 to 0.79+/-0.06 keV and the ratio of Fe XVII lines indicates a predominantly collisionally ionised plasma. Additionally we see indications of a recombining or underionized plasma in the Fe XVII line ratio. Derived electron densities are 0.106+/-0.018 cm^-3 for the nuclear region and 0.025+/-0.003 cm^-3 for the outflow region closest to the centre. The RGS image in the O VIII line energy clearly shows the morphology of an outflow extending out to ~750 pc along the south-east minor axis, while the north-west part of the outflow is not seen in O VIII due to the heavy absorption by the galactic disc. This is the first time that the hot wind fluid has been detected directly. The limb brightening seen in Chandra and XMM-Newton EPIC observations is only seen in the energy range containing the Fe XVII lines (550-750 eV). In all other energy ranges between 400 and 2000 eV no clear evidence of limb brightening could be detected.Comment: 14 pages, 7 figures, 3 tables, accepted for publication on A&A, v2: typos corrected, electron densities and table with emission line flux added, discussion improve

    Complex cytogenetic rearrangements at the DURS1 locus in syndromic Duane retraction syndrome

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    Key Clinical Message A patient with syndromic Duane retraction syndrome harbors a chromosome 811.1q13.2 inversion and 8p11.1-q12.3 marker chromosome containing subregions with differing mosaicism and allele frequencies. This case highlights the potential requirement for multiple genetic methods to gain insight into genotype–phenotype correlation, and ultimately into molecular mechanisms that underlie human disease

    Insights into the demographic history of african pygmies from complete mitochondrial genomes

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    Pygmy populations are among the few hunter-gatherers currently living in sub-Saharan Africa and are mainly represented by two groups, Eastern and Western, according to their current geographical distribution. They are scattered across the Central African belt and surrounded by Bantu-speaking farmers, with whom they have complex social and economic interactions. To investigate the demographic history of Pygmy groups, a population approach was applied to the analysis of 205 complete mitochondrial DNA (mtDNA) sequences from ten central African populations. No sharing of maternal lineages was observed between the two Pygmy groups, with haplogroup L1c being characteristic of the Western group but most of Eastern Pygmy lineages falling into subclades of L0a, L2a, and L5. Demographic inferences based on Bayesian coalescent simulations point to an early split among the maternal ancestors of Pygmies and those of Bantu-speaking farmers (similar to 70,000 years ago [ya]). Evidence for population growth in the ancestors of Bantu-speaking farmers has been observed, starting similar to 65,000 ya, well before the diffusion of Bantu languages. Subsequently, the effective population size of the ancestors of Pygmies remained constant over time and similar to 27,000 ya, coincident with the Last Glacial Maximum, Eastern and Western Pygmies diverged, with evidence of subsequent migration only among the Western group and the Bantu-speaking farmers. Western Pygmies show signs of a recent bottleneck 4,000-650 ya, coincident with the diffusion of Bantu Languages, whereas Eastern Pygmies seem to have experienced a more ancient decrease in population size (20,000-4,000 ya). In conclusion, the results of this first attempt at analyzing complete mtDNA sequences at the population level in sub-Saharan Africa not only support previous findings but also offer new insights into the demographic history of Pygmy populations, shedding new light on the ancient peopling of the African continent.Direccion General de Investigacion, Ministerio de Educacion y Ciencia, Spain [CGL2007-61016]; Direccio General de Recerca, Generalitat de Catalunya [2009SGR1101]info:eu-repo/semantics/publishedVersio

    Most of the extant mtDNA boundaries in South and Southwest Asia were likely shaped during the initial settlement of Eurasia by anatomically modern humans

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    BACKGROUND:Recent advances in the understanding of the maternal and paternal heritage of south and southwest Asian populations have highlighted their role in the colonization of Eurasia by anatomically modern humans. Further understanding requires a deeper insight into the topology of the branches of the Indian mtDNA phylogenetic tree, which should be contextualized within the phylogeography of the neighboring regional mtDNA variation. Accordingly, we have analyzed mtDNA control and coding region variation in 796 Indian (including both tribal and caste populations from different parts of India) and 436 Iranian mtDNAs. The results were integrated and analyzed together with published data from South, Southeast Asia and West Eurasia.RESULTS:Four new Indian-specific haplogroup M sub-clades were defined. These, in combination with two previously described haplogroups, encompass approximately one third of the haplogroup M mtDNAs in India. Their phylogeography and spread among different linguistic phyla and social strata was investigated in detail. Furthermore, the analysis of the Iranian mtDNA pool revealed patterns of limited reciprocal gene flow between Iran and the Indian sub-continent and allowed the identification of different assemblies of shared mtDNA sub-clades.CONCLUSIONS:Since the initial peopling of South and West Asia by anatomically modern humans, when this region may well have provided the initial settlers who colonized much of the rest of Eurasia, the gene flow in and out of India of the maternally transmitted mtDNA has been surprisingly limited. Specifically, our analysis of the mtDNA haplogroups, which are shared between Indian and Iranian populations and exhibit coalescence ages corresponding to around the early Upper Paleolithic, indicates that they are present in India largely as Indian-specific sub-lineages. In contrast, other ancient Indian-specific variants of M and R are very rare outside the sub-continent.This item is part of the UA Faculty Publications collection. For more information this item or other items in the UA Campus Repository, contact the University of Arizona Libraries at [email protected]

    Supernova PTF12glz: a possible shock breakout driven through an aspherical wind

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    We present visible-light and ultraviolet (UV) observations of the supernova PTF12glz. The SN was discovered and monitored in near-UV and R bands as part of a joint GALEX and Palomar Transient Factory campaign. It is among the most energetic Type IIn supernovae observed to date (~10^51erg). If the radiated energy mainly came from the thermalization of the shock kinetic energy, we show that PTF12glz was surrounded by ~1 solar mass of circumstellar material (CSM) prior to its explosive death. PTF12glz shows a puzzling peculiarity: at early times, while the freely expanding ejecta are presumably masked by the optically thick CSM, the radius of the blackbody that best fits the observations grows at ~8000km/s. Such a velocity is characteristic of fast moving ejecta rather than optically thick CSM. This phase of radial expansion takes place before any spectroscopic signature of expanding ejecta appears in the spectrum and while both the spectroscopic data and the bolometric luminosity seem to indicate that the CSM is optically thick. We propose a geometrical solution to this puzzle, involving an aspherical structure of the CSM around PTF12glz. By modeling radiative diffusion through a slab of CSM, we show that an aspherical geometry of the CSM can result in a growing effective radius. This simple model also allows us to recover the decreasing blackbody temperature of PTF12glz. SLAB-Diffusion, the code we wrote to model the radiative diffusion of photons through a slab of CSM and evaluate the observed radius and temperature, is made available on-line.Comment: Sumbitted to ApJ. Comments are welcom

    Extended Y chromosome haplotypes resolve multiple and unique lineages of the Jewish priesthood

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    It has been known for over a decade that a majority of men who self report as members of the Jewish priesthood (Cohanim) carry a characteristic Y chromosome haplotype termed the Cohen Modal Haplotype (CMH). The CMH has since been used to trace putative Jewish ancestral origins of various populations. However, the limited number of binary and STR Y chromosome markers used previously did not provide the phylogenetic resolution needed to infer the number of independent paternal lineages that are encompassed within the Cohanim or their coalescence times. Accordingly, we have genotyped 75 binary markers and 12 Y-STRs in a sample of 215 Cohanim from diverse Jewish communities, 1,575 Jewish men from across the range of the Jewish Diaspora, and 2,099 non-Jewish men from the Near East, Europe, Central Asia, and India. While Cohanim from diverse backgrounds carry a total of 21 Y chromosome haplogroups, 5 haplogroups account for 79.5% of Cohanim Y chromosomes. The most frequent Cohanim lineage (46.1%) is marked by the recently reported P58 T->C mutation, which is prevalent in the Near East. Based on genotypes at 12 Y-STRs, we identify an extended CMH on the J-P58* background that predominates in both Ashkenazi and non-Ashkenazi Cohanim and is remarkably absent in non-Jews. The estimated divergence time of this lineage based on 17 STRs is 3,190 ± 1,090 years. Notably, the second most frequent Cohanim lineage (J-M410*, 14.4%) contains an extended modal haplotype that is also limited to Ashkenazi and non-Ashkenazi Cohanim and is estimated to be 4.2 ± 1.3 ky old. These results support the hypothesis of a common origin of the CMH in the Near East well before the dispersion of the Jewish people into separate communities, and indicate that the majority of contemporary Jewish priests descend from a limited number of paternal lineages

    Genetic Continuity in the Franco-Cantabrian Region: New Clues from Autochthonous Mitogenomes

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    Background: The Late Glacial Maximum (LGM),,20 thousand years ago (kya), is thought to have forced the people inhabiting vast areas of northern and central Europe to retreat to southern regions characterized by milder climatic conditions. Archaeological records indicate that Franco-Cantabria might have been the major source for the re-peopling of Europe at the beginning of the Holocene (11.5 kya). However, genetic evidence is still scarce and has been the focus of an intense debate. Methods/Principal Findings: Based on a survey of more than 345,000 partial control region sequences and the analysis of 53 mitochondrial DNA (mtDNA) genomes, we identified an mtDNA lineage, HV4a1a, which most likely arose in the Franco-Cantabrian area about 5.4 kya and remained confined to northern Iberia. Conclusions/Significance: The HV4a1a lineage and several of its younger branches reveal for the first time genetic continuity in this region and long-term episodes of isolation. This, in turn, could at least in part explain the unique linguistic and cultural features of the Basque region

    Preliminary Report: Missense mutations in the APOL gene family are associated with end stage kidney disease risk previously attributed to the MYH9 gene

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    MYH9 has been proposed as a major genetic risk locus for a spectrum of non-diabetic end stage kidney disease (ESKD). We use recently released sequences from the 1000 Genomes Project to identify two western African specific missense mutations (S342G and I384M) in the neighbouring APOL1 gene, and demonstrate that these are more strongly associated with ESKD than previously reported MYH9 variants. We also show that the distribution of these risk variants in African populations is consistent with the pattern of African ancestry ESKD risk previously attributed to the MYH9 gene. Additional associations were also found among other members of the APOL gene family, and we propose that ESKD risk is caused by western African variants in members of the APOL gene family, which evolved to confer protection against pathogens, such as Trypanosoma.Comment: 25 pages, 6 figure
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