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  • 1
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    A new overview of secular period changes of RR Lyrae stars in M5 (2016)
    Oxford University Press
    Details
    Publication Date: 2016-07-02
    Description: Secular period variations, $\beta =\dot{P}$ , in 76 RR Lyrae stars in the globular cluster M5 are analysed using our most recent CCD V photometry and the historical photometric data base available in the literature since 1889. This provides a time baseline of up to 118 yr for these variables. The analysis was performed using two independent approaches: first, the classical O – C behaviour of the time of maximum light, and second, via a grid ( P , β), where the solution producing the minimum scatter in the phased light curve is chosen. The results of the two methods agree satisfactorily. This allowed a new interpretation of the nature of the period changes in many RR Lyrae stars in M5. It is found that in 96 per cent of the stars studied no irregular or stochastic variations need to be claimed, but that 66 per cent of the population shows steady period increases or decreases, and that 34 per cent of the periods seem to have been stable over the last century. The lack of systematic positive or negative period variations in RR Lyrae stars in other globular clusters is addressed, and the paradigm of period changes being a consequence of stellar evolution is discussed in terms of chemical variations near the stellar core and of multiple stellar populations. In M5 we found a small positive average value of β and a small surplus of RRab stars with a period increase. Nevertheless, in M5 we have been able to isolate a group of likely evolved stars that systematically show positive, and in some cases large, period change rates.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
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  • 2
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    Active basement uplift of Sierra Pie de Palo (Northwestern Argentina): Rates and inception from 10Be cosmogenic nuclide concentrations (2015)
    Wiley
    In: Tectonics
    Details
    Publication Date: 2015-05-28
    Description: Quaternary tectonic and denudation rates are investigated for an actively growing basement anticline: the Sierra Pie de Palo range, which belongs to the Andean foreland of western Argentina (28°S-33°S). In this study, a detailedmorphometric analysis of the topography is combined with in situ-produced cosmogenic 10 Be concentrations measured in (1) surface boulders abandoned on alluvial terraces affected by fault activity (along the north bounding fault) and growth of the basement fold (along the southeastern border), (2) bedrock outcrops corresponding to an exhumed and folded, regional erosion surface, and (3) fluvial sediments sampled at the outlets of several watersheds. Along the eastern and northern borders of the range, incision and uplift rates have been estimated at approximately 0.5 and 1 mm/yr when integrated on Holocene and Pleistocene time scales, in close agreement with both long- (structural and basin evolution data) and short-term (GPS-derived velocity field) analyses. Cosmogenic-derived denudation and uplift rates combined with geomorphic characteristics of watersheds and river channels allows estimating the onset of the uplift at 4–6 Ma, followed by a more recent period of topographic rejuvenation at roughly 1–2 Ma, probably synchronous with steepening of the eastern and northern flanks of the anticline.
    Print ISSN: 0278-7407
    Electronic ISSN: 1944-9194
    Topics: Geosciences
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 3
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    Signaling of rat Frizzled-2 through phosphodiesterase and cyclic GMP (2002)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2002-12-10
    Description: The Frizzled-2 receptor (Rfz2) from rat binds Wnt proteins and can signal by activating calcium release from intracellular stores. We show that wild-type Rfz2 and a chimeric receptor consisting of the extracellular and transmembrane portions of the beta2-adrenergic receptor with cytoplasmic domains of Rfz2 also signaled through modulation of cyclic guanosine 3',5'-monophosphate (cGMP). Activation of either receptor led to a decline in the intracellular concentration of cGMP, a process that was inhibited in cells treated with pertussis toxin, reduced by suppression of the expression of the heterotrimeric GTP-binding protein (G protein) transducin, and suppressed through inhibition of cGMP-specific phosphodiesterase (PDE) activity. Moreover, PDE inhibitors blocked Rfz2-induced calcium transients in zebrafish embryos. Thus, Frizzled-2 appears to couple to PDEs and calcium transients through G proteins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ahumada, Adriana -- Slusarski, Diane C -- Liu, Xunxian -- Moon, Randall T -- Malbon, Craig C -- Wang, Hsien-yu -- T32-DK07521/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 2002 Dec 6;298(5600):2006-10.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Pharmacology, Diabetes and Metabolic Diseases Research Center, University Medical Center, SUNY-Stony Brook, Stony Brook, NY 11794-8651, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12471263" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; CHO Cells ; Calcium/metabolism ; Cricetinae ; Culture Media, Conditioned ; Cyclic GMP/*metabolism ; Embryo, Nonmammalian/metabolism ; Frizzled Receptors ; Guanosine 5'-O-(3-Thiotriphosphate)/pharmacology ; Molecular Sequence Data ; Pertussis Toxin/pharmacology ; Phosphodiesterase Inhibitors/pharmacology ; Phosphoric Diester Hydrolases/*metabolism ; Rats ; Receptors, Adrenergic, beta-2/chemistry/metabolism ; Receptors, G-Protein-Coupled ; Receptors, Neurotransmitter/chemistry/*metabolism ; Recombinant Fusion Proteins/metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; *Signal Transduction ; Transducin/genetics/metabolism ; Transfection ; Tumor Cells, Cultured ; Zebrafish
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 4
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    Live attenuated malaria vaccine designed to protect through hepatic CD8(+) T cell immunity (2011)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2011-09-10
    Description: Our goal is to develop a vaccine that sustainably prevents Plasmodium falciparum (Pf) malaria in 〉/=80% of recipients. Pf sporozoites (PfSPZ) administered by mosquito bites are the only immunogens shown to induce such protection in humans. Such protection is thought to be mediated by CD8(+) T cells in the liver that secrete interferon-gamma (IFN-gamma). We report that purified irradiated PfSPZ administered to 80 volunteers by needle inoculation in the skin was safe, but suboptimally immunogenic and protective. Animal studies demonstrated that intravenous immunization was critical for inducing a high frequency of PfSPZ-specific CD8(+), IFN-gamma-producing T cells in the liver (nonhuman primates, mice) and conferring protection (mice). Our results suggest that intravenous administration of this vaccine will lead to the prevention of infection with Pf malaria.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Epstein, J E -- Tewari, K -- Lyke, K E -- Sim, B K L -- Billingsley, P F -- Laurens, M B -- Gunasekera, A -- Chakravarty, S -- James, E R -- Sedegah, M -- Richman, A -- Velmurugan, S -- Reyes, S -- Li, M -- Tucker, K -- Ahumada, A -- Ruben, A J -- Li, T -- Stafford, R -- Eappen, A G -- Tamminga, C -- Bennett, J W -- Ockenhouse, C F -- Murphy, J R -- Komisar, J -- Thomas, N -- Loyevsky, M -- Birkett, A -- Plowe, C V -- Loucq, C -- Edelman, R -- Richie, T L -- Seder, R A -- Hoffman, S L -- 5R44AI055229-07/AI/NIAID NIH HHS/ -- 5R44AI058375-05/AI/NIAID NIH HHS/ -- 5R44AI058499-05/AI/NIAID NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2011 Oct 28;334(6055):475-80. doi: 10.1126/science.1211548. Epub 2011 Sep 8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉U.S. Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD 20910, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21903775" target="_blank"〉PubMed〈/a〉
    Keywords: Adolescent ; Adult ; Animals ; Antibodies, Protozoan/blood/immunology ; Antigens, Protozoan/immunology ; CD8-Positive T-Lymphocytes/*immunology ; Humans ; Injections, Intravenous ; Injections, Subcutaneous ; Interferon-gamma/biosynthesis/immunology ; Liver/*immunology ; Macaca mulatta ; Malaria Vaccines/administration & dosage/adverse effects/*immunology ; Malaria, Falciparum/*prevention & control ; Mice ; Middle Aged ; Plasmodium falciparum/*immunology ; Rabbits ; Sporozoites/*immunology ; Vaccines, Attenuated/administration & dosage/adverse effects/immunology ; Young Adult
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 5
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    Final report of the CCQM-K145: toxic and essential elements in bovine liver (2020)
    Institute of Physics
    Details
    Publication Date: 2020-01-01
    Print ISSN: 0026-1394
    Electronic ISSN: 1681-7575
    Topics: Electrical Engineering, Measurement and Control Technology
    Published by Institute of Physics
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  • 6
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    Probing the Large Magellanic Cloud's recent chemical enrichment history through its star clusters (2015)
    Oxford University Press
    Details
    Publication Date: 2015-05-02
    Description: We present Washington system colour–magnitude diagrams (CMDs) for 17 practically unstudied star clusters located in the bar as well as in the inner disc and outer regions of the Large Magellanic Cloud (LMC). Cluster sizes were estimated from star counts distributed throughout the entire observed fields. Based on the best fits of theoretical isochrones to the cleaned ( C – T 1 , T 1 ) CMDs, as well as on the T 1 parameter and the standard giant branch method, we derive ages and metallicities for the cluster sample. Four objects are found to be intermediate-age clusters (1.8–2.5 Gyr), with [Fe/H] ranging from –0.66 to –0.84. With the exception of SL 263, a very young cluster (~16 Myr), the remaining 12 objects are aged between 0.32 and 0.89 Gyr, with their [Fe/H] values ranging from –0.19 to –0.50. We combined our results with those for other 231 clusters studied in a similar way using the Washington system. The resulting age–metallicity relationship shows a significant dispersion in metallicities, whatever age is considered. Although there seems to exist a clear tendency for the younger clusters to be more metal rich than the intermediate ones, we believe that none of the chemical evolution models currently available in the literature reasonably well represents the recent chemical enrichment processes in the LMC clusters. The present sample of 17 clusters is part of our ongoing project of generating a data base of LMC clusters homogeneously studied using the Washington photometric system and applying the same analysis procedure.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
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  • 7
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    NGC 2849 and NGC 6134: two more BOCCE open clusters (2013)
    Oxford University Press
    Details
    Publication Date: 2013-02-28
    Description: We present CCD photometry of two southern open clusters. As part of the Bologna Open Cluster Chemical Evolution project we obtained BVI and UBVI imaging for NGC 2849 and NGC 6134, respectively. By means of the synthetic colour–magnitude diagram method and using various evolutionary sets of stellar evolution tracks with various metallicities, we determined at the same time age, distance and reddening. We also determined an approximate metallicity for NGC 2849, for which the information is not available from sounder methods like high-resolution spectroscopy. NGC 2849 turned to be 0.85–1.0 Gyr old with a solar metallicity. The foreground reddening is E ( B  – V ) = 0.28 – 0.32, and the true distance modulus ( m  – M ) 0  = 13.8–13.9. For NGC 6134 we did not obtain fully consistent answers from the V , B  – V and V , V  – I photometry, an unexpected problem, since both the metallicity and the reddening are known (from high-resolution spectroscopy and the U  – B , B  – V two colours diagram, respectively). This may either indicate a difficulty of current models (evolutionary tracks and/or models of atmosphere) to accurately reproduce colours, or be related to differences in the metal mixture assumed by the models and those of the clusters. Assuming the spectroscopic abundance and the colour excess [ E ( B  – V ) = 0.35] from the U  – B , B  – V plot, we derived a best age between 0.82 and 0.95 Gyr and a distance modulus 10.5. In agreement with previous studies, the NGC 6134 colour–magnitude diagram shows also a clear main sequence gap at V  ~ 15 and B-V ~ 0.9–1.0 that is unexplained by canonical stellar evolution models.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
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  • 8
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    IC 2395 and BH 47: Only one open cluster in the Vela constellation (2003)
    EDP Sciences
    Details
    Publication Date: 2003-10-01
    Print ISSN: 0004-6361
    Electronic ISSN: 1432-0746
    Topics: Physics
    Published by EDP Sciences
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  • 9
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    On the calibration of the COBE/IRAS dust emission reddening maps (2003)
    EDP Sciences
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    Publication Date: 2003-09-01
    Print ISSN: 0004-6361
    Electronic ISSN: 1432-0746
    Topics: Physics
    Published by EDP Sciences
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  • 10
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    Improvements on the fundamental parameters of the open cluster Tombaugh 1 through Washington system photometry (2004)
    EDP Sciences
    Details
    Publication Date: 2004-06-29
    Print ISSN: 0004-6361
    Electronic ISSN: 1432-0746
    Topics: Physics
    Published by EDP Sciences
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