594 research outputs found

    The birthplace and age of the isolated neutron star RX J1856.5-3754

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    X-ray observations unveiled various types of radio-silent Isolated Neutron Stars (INSs), phenomenologically very diverse, e.g. the Myr old X-ray Dim INS (XDINSs) and the kyr old magnetars. Although their phenomenology is much diverse, the similar periods (P=2--10 s) and magnetic fields (~10^{14} G) suggest that XDINSs are evolved magnetars, possibly born from similar populations of supermassive stars. One way to test this hypothesis is to identify their parental star clusters by extrapolating backward the neutron star velocity vector in the Galactic potential. By using the information on the age and space velocity of the XDINS RX J1856.5-3754, we computed backwards its orbit in the Galactic potential and searched for its parental stellar cluster by means of a closest approach criterion. We found a very likely association with the Upper Scorpius OB association, for a neutron star age of 0.42+/-0.08 Myr, a radial velocity V_r^NS =67+/- 13$ km s^{-1}, and a present-time parallactic distance d_\pi^NS = 123^{+11}_{-15} pc. Our result confirms that the "true" neutron star age is much lower than the spin-down age (tau_{sd}=3.8 Myrs), and is in good agreement with the cooling age, as computed within standard cooling scenarios. The mismatch between the spin-down and the dynamical/cooling age would require either an anomalously large breaking index (n~20) or a decaying magnetic field with initial value B_0 ~ 10^{14} G. Unfortunately, owing to the uncertainty on the age of the Upper Scorpius OB association and the masses of its members we cannot yet draw firm conclusions on the estimated mass of the RX J1856.5-3754 progenitor.Comment: 6 pages, accepted for publication on Monthly Notices of the Royal Astronomical Societ

    Polymorphism of Genetic variability of gene in sheep

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    MUC1 gene encodes the polypeptide of a mucin present on the apical surface of the secreting mammary cells during lactation and on the surface of the milk fat globules (Mather, 2000). MUC1 contains a minisatellite region: the sequence, coding for the extracellular protein domain, consists mostly of a motif of 60 bp that in human, cattle and goat is tandemly repeated a variable number of times (VNTR polymorphism), giving rise to molecular variants of different size (Patton et al., 1995)

    Observations of Isolated Neutron Stars with the ESO Multi-Conjugate Adaptive Optics Demonstrator

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    High-energy observations have unveiled peculiar classes of isolated neutron stars which, at variance with radio pulsars, are mostly radio silent and not powered by the star rotation. Among these objects are the magnetars, hyper-magnetized neutron stars characterized by transient X-ray/gamma-ray emission, and neutron stars with purely thermal, and in most cases stationary, X-ray emission (a.k.a., X-ray dim isolated neutron stars or XDINSs). While apparently dissimilar in their high-energy behavior and age, both magnetars and XDINSs have similar periods and unusually high magnetic fields. This suggests a tantalizing scenario where the former evolve into the latter.Discovering so far uninvestigated similarities between the multi-wavelength properties of these two classes would be a further step forward to establish an evolutionary scenario. A most promising channels is the near infrared (NIR) one, where magnetars are characterized by a distinctive spectral flattening with respect to the extrapolation of the soft X-ray spectrum.We observed the two XDINSs RX J0420.0-5022 and RX J1856.5-3754 with the Multi-Conjugate Adaptive Optics Demonstrator (MAD) at the Very Large Telescope (VLT) as part of the instrument guaranteed time observations program, to search for their NIR counterparts. Both RX J1856.5-3754 and RX J0420.0-5022 were not detected down to K_s ~20 and Ks ~21.5, respectively. In order to constrain the relation between XDINSs and magnetars it would be of importance to perform deeper NIR observations. A good candidate is 1RXS J214303.7+065419 which is the XDINS with the highest inferred magnetic field.Comment: Accepted for publication in Astronomy and Astrophysic

    Polyalkylene carbonate obtained from biodegradable co2 and with self-healing properties

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    The present invention relates to a polyalkylene carbonate, preferably PRC, and the use thereof in packaging, in coating surfaces, in cosmetics, in the biomedical or textile sector or to produce composite materials or moisture absorption devices. Preferably, said polyalkylene carbonate is obtained by reacting CO2 with an alkyl epoxide preferably containing at least 3 atoms of carbon, preferably propylene oxide, in the presence of a zinc dicarboxylate catalyst; said catalyst being obtained by reacting, with a preferably saturated aliphatic dicarboxylic acid, a zinc-based compound comprising a mixture of ZnO and a compound having the general formula (I): Znx(0H)y(L)z-nH2 O (I) wherein L is selected in the group consisting of: NO3, CH3CO2, (SO4)0.5, halide, and acetyl acetonate (AcAc), 2x = y + z; wherein x is comprised between 1 and 5, y is comprised between 1 and 8, z is comprised between 1 and 2, and n is comprised between 0 and 20

    Diagnostic pitfalls in the assessment of congenital hypopituitarism.

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    BACKGROUND: The diagnosis of congenital hypopituitarism is difficult and oftendelayed because its symptoms are nonspecific.AIM: To describe the different clinical presentations of children with congenitalhypopituitarism to reduce the time for diagnosis and to begin a precocious andappropriate treatment.STUDY DESIGN: We analyzed a cohort of five children with congenitalhypopituitarism, describing their clinical, biochemical and radiologicalcharacteristics from the birth to diagnosis.RESULTS: As first sign of the disease, all of five patients presented a neonatal hypoglycemia, associated in four cases with jaundice. In all these four cases,the clinicians hypothesized a metabolic disease delaying the diagnosis, which wasperformed in only two cases within the neonatal period. In the other three cases,the diagnosis was formulated at 2, 5 and 8 years of life because there was severeand precocious growth impairment.CONCLUSIONS: It is important to suspect congenital hypopituitarism in thepresence of persistent neonatal hypoglycemia associated with jaundice and of aprecocious and severe reduction of the growth velocity in childhood. In all thesecases, it is necessary to undertake a hypothalamic-pituitary magnetic resonanceimaging scan as soon as possible, and to start appropriate treatment

    Identification of snps associated with somatic cell score in candidate genes in italian holstein friesian bulls

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    Mastitis is an infectious disease affecting the mammary gland, leading to inflammatory reactions and to heavy economic losses due to milk production decrease. One possible way to tackle the antimicrobial resistance issue stemming from antimicrobial therapy is to select animals with a genetic resistance to this disease. Therefore, aim of this study was to analyze the genetic variability of the SNPs found in candidate genes related to mastitis resistance in Holstein Friesian bulls. Target regions were amplified, sequenced by Next-Generation Sequencing technology on the Illumina® MiSeq, and then analyzed to find correlation with mastitis related phenotypes in 95 Italian Holstein bulls chosen with the aid of a selective genotyping approach. On a total of 557 detected mutations, 61 showed different genotype distribution in the tails of the deregressed EBVs for SCS and 15 were identified as significantly associated with the phenotype using two different approaches. The significant SNPs were identified in intergenic or intronic regions of six genes, known to be key components in the immune system (namely CXCR1, DCK, NOD2, MBL2, MBL1 and M-SAA3.2). These SNPs could be considered as candidates for a future genetic selection for mastitis resistance, although further studies are required to assess their presence in other dairy cattle breeds and their possible negative correlation with other traits
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