A study of the long term variability of RX J1856.5-3754 with XMM-Newton

We report on a detailed spectral analysis of all the available XMM-Newton data of RX J1856.5-3754, the brightest and most extensively observed nearby, thermally emitting neutron star. Very small variations (~1-2%) in the single-blackbody temperature are detected, but are probably due to an instrumental effect, since they correlate with the position of the source on the detector. Restricting the analysis to a homogeneous subset of observations, with the source at the same detector position, we place strong limits on possible spectral or flux variations from March 2005 to present-day. A slightly higher temperature (kT~61.5 eV, compared to the average value kT~61 eV) was instead measured in April 2002. If this difference is not of instrumental origin, it implies a rate of variation of about 0.15 eV/yr between April 2002 and March 2005. The high-statistics spectrum from the selected observations is well fit by the sum of two blackbody models, which extrapolate to an optical flux level in agreement with the observed value.Comment: 4 pages, to appear in the proceedings of the ERPM conference, Zielona Gora, April 201

Expeditious Calibration Method for Quantification of Odorous Mixtures via GC

An odour sample is generally a complex matrix consisting of numerous molecules (mostly volatile organic compounds, VOCs) chemically different from each other, and which can be perceived by the human nose. In order to chemically characterize this complex gaseous matrix, gas-chromatography (GC) is commonly used. By this analytical technique, it is possible to obtain the resolution of odour gaseous mixtures in order to qualify and quantify the compounds. However, the quantification is a tricky operation based on the comparison of the sample under examination with purpose-made gas mixtures containing a compound, chosen as a standard, at known concentration. Commonly, these mixtures are obtained from cylinders of compressed gases, the use of which involves problems relating to their management, thermodynamic equilibrium feasibility, considerable economic outlay and not-negligible procurement times. This paper describes a method, proposed as a versatile and simple alternative to the use of such cylinders, for preparing gaseous calibration standards at known concentration. The method involves the continuous injection of VOC in liquid form, by means of a syringe pump, into a stream of neutral gas, such as air or nitrogen, which acts as diluent gas, controlled by a mass flow meter. Exploiting the volatility of the compounds used, it is possible to generate a continuous gas stream, exiting the system, containing the selected VOC at the desired concentration, which can be directly used as calibration standard

the effects of control measures on the economic burden associated with epidemics of avian influenza in italy

In 1999, Italy experienced a devastating epidemic of high-pathogenicity avian influenza (HPAI) caused by an H7N1 virus subtype. After this epidemic, a ministerial decree was passed to implement control measures for low-pathogenicity avian influenza (LPAI) due to H5 and H7 subtypes. We investigated whether these control measures have decreased the public expenditure associated with epidemics of LPAI and HPAI by comparing the direct and consequential losses of the 1999 epidemic to the losses associated with successive epidemics. The estimated total economic burden of the epidemics was about euro650 million (euro217 million in direct losses and euro433 million in consequential losses). The 1999 epidemic accounted for most of these losses (euro507 million: euro112 million in direct losses and euro395 million in consequential losses), whereas the total economic burden for the 5 successive LPAI was euro143 million (euro105 million in direct losses and euro38 million in consequential losses). These results demonstrate that the implementation of a coordinated set of disease-control measures, which included both emergency and prophylactic vaccination, was able to reduce the overall costs associated with avian influenza epidemics. The results also show that the application of adequate LPAI control measures may limit the risk of emergence of an HPAI virus in an area with a high poultry density, allowing the complete disruption of the poultry market and its huge associated costs to be avoided

Toxicity of oxaliplatin rechallenge in metastatic colorectal cancer.

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Polymorphism of Genetic variability of gene in sheep

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)

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

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

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

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

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

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