456 research outputs found

    The helium spread in the Globular cluster 47 Tuc

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    Spectroscopy has shown the presence of the CN band dicothomy and the Na-O anticorrelations for 50--70% of the investigated samples in the cluster 47 Tuc, otherwise considered a "normal" prototype of high metallicity clusters from the photometric analysis. Very recently, the re-analysis of a large number of archival HST data of the cluster core has been able to put into evidence the presence of structures in the Sub Giant Branch: it has a brighter component with a spread in magnitude by \sim0.06 mag and a second one, made of about 10% of stars, a little fainter (by \sim0.05 mag). These data also show that the Main Sequence of the cluster has an intrinsic spread in color which, if interpreted as due to a small spread in helium abundance, suggests Δ\DeltaY\sim0.027. In this work we examine in detail whether the Horizontal Branch morphology and the Sub Giant structure provide further independent indications that a real --although very small-helium spread is present in the cluster. We re--analyze the HST archival data for the Horizontal Branch of 47 Tuc, obtaining a sample of \sim500 stars with very small photometric errors, and build population synthesis based on new models to show that its particular morphology can be better explained by taking into account a spread in helium abundance of 2% in mass. The same variation in helium is able to explain the spread in luminosity of the Sub Giant Branch, while a small part of the second generation is characterized by a small C+N+O increase and provides an explanation for the fainter Sub Giant Branch. We conclude that three photometric features concur to form the paradigm that a small but real helium spread is present in a cluster that has no spectacular evidence for multiple populations like those shown by other massive clusters.Comment: Accepted for publication in the MNRAS on 2010 June 8. Received 2010 May 19; in original form 2010 February 9. 7 pages and 3 figures. No table

    Análise espacial das mudanças na cobertura e uso das terras em Santarém e Belterra, Pará, Brasil: armadilhas metodológicas associadas.

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    Através de um estudo de caso, indicamos como a delimitação da área de estudo pode influenciar o resultado de análises multiescalares em processos espaciais de mudanças na cobertura e uso da terra na Amazônia. Partindo dos limites dos municípios de Santarém e Belterra no oeste do Estado do Pará, definimos três níveis de delimitação da área de estudo. O primeiro nível abrange uma região que foi arbitrariamente definida e denominada sub-região de Santarém e Belterra. O segundo nível, uma parte do primeiro, corresponde ao limite do entorno de lotes estabelecidos pelo INCRA na década de 1970, tratando-se portanto de uma área de ocupação consolidada. O terceiro nível corresponde às zonas de influência de quatro eixos viários inseridos dentro da área de ocupação consolidada, subdivididos em subáreas norte e sul, num total de oito subáreas do segundo nível de delimitação. Para cada nível, aplicamos métricas de paisagem sobre mapeamentos temáticos do satélite Landsat obtidos para os anos de 1986 a 2005 e as associamos com dados sociodemográficos obtidos em levantamentos realizados em 2003. Os resultados mostram que as peculiaridades da dinâmica de ocupação em cada nível permitem melhor identificar padrões e processos na composição da estrutura da paisagem. Os dados obtidos para os três níveis de delimitação são complementares, possibilitando uma compreensão mais abrangente do que aquela que se poderia obter pelo estudo de um único nível

    PTEN hamartoma tumor syndromes in childhood: description of two cases and a proposal for follow-up protocol

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    PTEN hamartoma tumor syndromes (PHTS) are a spectrum of hamartomatous overgrowth syndromes associated with germline mutations in the tumor suppressor PTEN gene located on 10q23.3. It is widely accepted that two of these disorders,Cowden syndrome and Bannayan–Riley–Ruvalcaba syndrome, are allelic conditions. BecausePTENmutations are not identifiable in every case of the PHTS phenotype, the inability to detect a mutation within thePTENgene does not invalidate the clinical diagnosis of Cowden syndrome, or Bannayan–Riley–Ruvalcaba syndrome, in patients who meet diagnostic criteria for these disorders. PTEN mutations are associated with an increased risk for developing breast, thyroid, endometrial, and sometimes renal cancers. Thus, cancer surveillance is the cornerstone of PHTS patient management. Although a consensus cancer surveillance protocol has not been formally instituted, all PTEN mutation carriers should adopt the cancer surveillance strategies proposed for patients with Cowden syndrome. In addition, because gastrointestinal and vascular complications can be more severe in Bannayan– Riley–Ruvalcaba syndrome than in Cowden syndrome, patients with Bannayan–Riley–Ruvalcaba syndrome should be monitored from this point of view too. In this study, we report on two cases with Bannayan–Riley–Ruvalcaba phenotype that showed two different PTEN mutations.Wealso propose practice recommendations for management of PHTS patient

    A paradigmatic autistic phenotype associated with loss of PCDH11Y and NLGN4Y genes

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    Background: Most studies relative to Y chromosome abnormalities are focused on the sexual developmental disorders. Recently, a few studies suggest that some genes located on Y chromosome may be related to different neurodevelopment disorders. Case presentation: We report a child with sexual developmental disorder associated with a peculiar phenotype characterized by severe language impairment and autistic behaviour associated with a mosaicism [45,X(11)/46,XY(89)] and a partial deletion of the short and long arm of Y chromosome (del Yp11.31q11.23) that also involves the loss of both PCDH11Y and NLGN4Y genes. To our knowledge no study has ever reported the occurrence of the lack of both PCDH11Y and NLGN4Y located in the Y chromosome in the same patient. Conclusions: We hypothesized a functional complementary role of PCDH11Y and NLGN4Y within formation/maturation of the cerebral cortex. The impairment of early language development may be mainly related to the lack of PCDH11Y that underlies the early language network development and the later appearance of the autistic behaviour may be mainly related to deficit of inhibitory glicinergic neurotransmission NLGN4Y-linked

    Commonalities and distinctions between two neurodevelopmental disorder subtypes associated with SCN2A and SCN8A variants and literature review

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    This study was aimed to analyze the commonalities and distinctions of voltage-gated sodium channels, Nav1.2, Nav1.6, in neurodevelopmental disorders. An observational study was performed including two patients with neurodevelopmental disorders. The demographic, electroclinical, genetic, and neuropsychological characteristics were analyzed and compared with each other and then with the subjects carrying the same genetic variants reported in the literature. The clinical features of one of them argued for autism spectrum disorder and developmental delay, the other for intellectual disability, diagnoses confirmed by the neuropsychological assessment. The first patient was a carrier of SCN2A (p.R379H) variant while the second was carrier of SCN8A (p.E936K) variant, both involving the pore loop of the two channels. The results of this study suggest that the neurodevelopmental disorders without overt epilepsy of both patients can be the consequences of loss of function of Nav1.2/Nav1.6 channels. Notably, the SCN2A variant, with an earlier expression timing in brain development, resulted in a more severe phenotype as autism spectrum disorder and developmental delay, while the SCN8A variant, with a later expression timing, resulted in a less severe phenotype as intellectual disability

    Invasive group B streptococcal infections in adults, France (2007–2010)

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    AbstractGroup B streptococcus (GBS) has emerged as an important cause of invasive infection in adults. Here, we report the clinical and microbiological characteristics of 401 non-redundant GBS strains causing adult invasive infections collected during a 4-year period (2007–2010). Bacteraemia without focus (43.4%) and bone and joint infections (18.7%) were the main clinical manifestations. The distribution of capsular polysaccharide (CPS) type showed that types Ia, III, and V accounted for 71.8% of all strains. Resistance to erythromycin increased from 20.2% in 2007 to 35.3% in 2010, and was mainly associated with CPS type V harbouring the erm(B) resistant determinant

    Cabozantinib for the treatment of solid tumors: a systematic review

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    Cabozantinib; Hepatocellular carcinoma; Solid tumorCabozantinib; Carcinoma hepatocel·lular; Tumor sòlidCabozantinib; Carcinoma hepatocelular; Tumor sólidoBackground: Cabozantinib is approved, in various settings, for the treatment of renal cell carcinoma, medullary thyroid cancer, and hepatocellular carcinoma, and it has been investigated for the treatment of other cancers. With the available evidence and the real-world performance of cabozantinib compared with clinical trial data, we performed a systematic review of cabozantinib monotherapy as treatment for solid tumors in adults. Methods: This study was designed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses and registered with PROSPERO (CRD42020144680). We searched for clinical and observational studies of cabozantinib monotherapy for solid tumors using Embase, MEDLINE, and Cochrane databases (October 2020), and screened relevant congress abstracts. Eligible studies reported clinical or safety outcomes, or biomarker data. Small studies (n < 25) and studies of cabozantinib combination therapies were excluded. Quality was assessed using National Institute for Health and Care Excellence methodology, and study characteristics were described qualitatively. Results: Of 2888 citations, 114 were included (52 randomized studies, 29 observational studies, 32 nonrandomized phase I or II studies or pilot trials, and 1 analysis of data from a randomized study and a nonrandomized study). Beyond approved indications, other tumors studied were castration-resistant prostate cancer, urothelial carcinoma, Ewing sarcoma, osteosarcoma, uveal melanoma, non-small-cell lung cancer, Merkel cell carcinoma, glioblastoma, pheochromocytomas and paragangliomas, cholangiocarcinoma, gastrointestinal stromal tumor, colorectal cancer, salivary gland cancer, carcinoid and pancreatic neuroendocrine tumors, and breast, endometrial and ovarian cancers. The most common adverse events were hypertension, diarrhea, and fatigue. Conclusion: The identified evidence demonstrates the positive efficacy/effectiveness of cabozantinib monotherapy in various solid tumor types, with safety findings being consistent with those observed with other VEGFR-targeting tyrosine kinase inhibitors. When available, real-world findings were consistent with the data reported from clinical trials. A limitation of this review is the high proportion of abstracts; however, this allowed us to capture the most up-to-date findings.The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study was funded by Ipsen

    The first magnetic maps of a pre-main sequence binary star system - HD 155555

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    We present the first maps of the surface magnetic fields of a pre-main sequence binary system. Spectropolarimetric observations of the young, 18 Myr, HD 155555 (V824 Ara, G5IV + K0IV) system were obtained at the Anglo-Australian Telescope in 2004 and 2007. Both datasets are analysed using a new binary Zeeman Doppler imaging (ZDI) code. This allows us to simultaneously model the contribution of each component to the observed circularly polarised spectra. Stellar brightness maps are also produced for HD 155555 and compared to previous Doppler images. Our radial magnetic maps reveal a complex surface magnetic topology with mixed polarities at all latitudes. We find rings of azimuthal field on both stars, most of which are found to be non-axisymmetric with the stellar rotational axis. We also examine the field strength and the relative fraction of magnetic energy stored in the radial and azimuthal field components at both epochs. A marked weakening of the field strength of the secondary star is observed between the 2004 and 2007 epochs. This is accompanied by an apparent shift in the location of magnetic energy from the azimuthal to radial field. We suggest that this could be indicative of a magnetic activity cycle. We use the radial magnetic maps to extrapolate the coronal field (by assuming a potential field) for each star individually - at present ignoring any possible interaction. The secondary star is found to exhibit an extreme tilt (~75 deg) of its large scale magnetic field to that of its rotation axis for both epochs. The field complexity that is apparent in the surface maps persists out to a significant fraction of the binary separation. Any interaction between the fields of the two stars is therefore likely to be complex also. Modelling this would require a full binary field extrapolation.Comment: 17 pages, 12 figures, accepted for publication in MNRA
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