899 research outputs found
BeppoSAX observations of Seyfert 1s in the Piccinotti sample I: poorly studied sources
In this work we present the first of two papers devoted to the study of the
X-ray spectral characteristics of Seyfert 1 galaxies in the Piccinotti sample.
In particular we analyse here the BeppoSAX broad band (0.1-100 keV) data of 4
objects which, despite their X-ray brightness, have been historically poorly
studied due to their late identification with an AGN; these are H0111-149
(MKN1152), H0235-525 (ESO198-G24), H0557-385 (IRAS F05563-3820) and H1846-786
(IRAS F18389-7834). We have assumed for all the sources a baseline model which
includes a power law with an exponential cut-off plus a reflection component
and an iron K_alpha line; we have also searched for the presence of intrinsic
absorption and/or a soft excess component. Our analysis indicates the presence
of complex absorption in two objects (H0557-385 and H0111-149) best described
by a combination of two uniform absorbers, one cold and one warm. Only in one
source, H0557-385, a soft excess component has been measured. The primary
continuum is best described by a canonical power law (Gamma=1.7-2) with a high
energy cut-off in the range 40-130 keV. A cold reflection component is likely
present in all sources with values ranging from less than 0.6 to higher than 2.
In 3 out of 4 objects we find a cold iron line having equivalent width typical
of Seyfert 1s (100-200 eV).Comment: 6 pages, 2 figures, accepted for publication as a Research Note in
Astronomy and Astrophysic
First-line therapy in HER2 positive metastatic breast cancer. Is the mosaic fully completed or are we missing additional pieces?
The discovery of human epidermal growth factor receptor 2 (HER2) and its role in the biology of breast cancer and the subsequent development of HER2-targeted therapies, have dramatically improved clinical outcomes for women with early-stage and advanced HER2-positive breast cancer (BC). HER-2 targeted therapies represent a major step forward in achieving the goal of delivering individualized targeted therapy for BC, and trastuzumab was the first anti-HER-2 strategy to be approved for treatment of HER-2 positive BC. This review discusses the treatment of metastatic HER2-positive BC and describes efficacy and safety of novel anti-HER2 target therapies in first-line metastatic settings and the future challenges include refining such treatments, reducing toxicity and simultaneously developing innovative therapies. Furthermore, combinations of trastuzumab and drugs targeting the downstream pathway are described. In the next future will be possible to use an ample armamentarium of combination therapies directed against HER2 and key signaling components integrated in the HER network. This approach will allow clinicians to tailor the management of the individual patient on the basis of tumor- specific biomarker profiles. There is an urgent need for prospective biomarker-driven trials to identify patients for whom targeting is cost-effective
Activity of eribulin mesylate in brain metastasis from breast cancer. a stone in a pond?
Background: Brain metastases develop in approximately 10-25% of patients with metastatic breast cancer (MBC) and are associated with a very poor prognosis. Case Report: We report the case of a 40-year-old woman with MBC and associated lung, bone, liver, and brain metastases, who experienced a time to progression of several months with eribulin after whole-brain radiotherapy (WBRT), 2 lines of chemotherapy, and 1 line of hormonal therapy, maintaining a good toxicity profile. Discussion: Eribulin, in association with local treatment such as WBRT, can be well tolerated and effective in achieving a long progression-free survival and a good control of brain metastases in patients with MBC who have received multiple lines of treatment. The vascular remodeling properties of eribulin, combined with brain radiotherapy, might facilitate the passage of eribulin across the blood brain barrier, improving brain response. Conclusion: Our anecdotal experience suggests that eribulin may have a potentially beneficial effect on brain metastases while maintaining a good systemic control of the disease in patients with MBC
On a Nonlocal Boundary Value Problem for Second Order Nonlinear Singular Differential Equations
Criteria for the existence and uniqueness of a solution of a nonlocal second order boundary value problem are estabilished. These criteria apply, in particular, to the case when the nonlinearity has nonintegrable singularities
The X-ray spectra of Compton-thick Seyfert 2 galaxies as seen by BeppoSAX
Results from BeppoSAX observations of Compton--thick Seyfert 2 galaxies are
summarized and reviewed, and their general properties derived and discussed. In
five out of the seven observed sources, the nucleus is directly visible at high
X-ray energies, where the photons penetrate absorbers with column densities in
the range 1.1-4.3x10^{24} cm-2 (in the other two sources, NGC 1068 and NGC
7674, the nucleus is instead totally obscured at all energies, implying even
larger column densities). In most sources there is unambiguous evidence of a
reflection component from optically thick, cold matter, while in two (or maybe
four) cases there is also evidence of reflection from ionized matter. For the
sources with a measured X-ray luminosity, a comparison with the infrared
luminosity is made; while in two cases (the Circinus galaxy and NGC 4945) the
IR emission appears to be dominated by starburst activity, in the other three
sources (NGC 6240, Mrk 3 and TOL 0109-383) it is likely to be dominated by
reprocessing of the UV and X-ray photons emitted by an AGN.Comment: Accepted for publication in MNRA
A complex idea of human Being : The contribution of neuroscience and ecological social and human approach in the construction of competent and inclusive educational context
According to the current lines of contemporary research, the aim of the framework of inclusive education is to respond to the diversity and learning differences of all students, through a different environmental organization for everyone. Brain development is largely a process that depends on experience, in both positive and negative terms (Oliviero, 2017). According to the principle of neuronal plasticity, the brain modifies its structure on the basis of environmental stimuli: in fact, it is environmental and interpersonal experiences that modify our brain structures. In the educational field, it is therefore essential to structure contexts and learning opportunities that generate interest, curiosity, and participation, in heterogeneous environments such as that of todayâs school, but respecting the development of each student. The contribution of contemporary neuroscience allows, today, embody the idea of a complex being human. The relationships and the mediators that are used at school, are the signs that students received. That can stimulate the perceptive apparatus and support the development of identity and the relationship between similar (inter-objectivity). In this work we will present, through the perspective of the principles of Universal Design (Rose and Meyer, 2002) how an active, multi-perspective and varied learning, stimulating learning, participation, and a development of soft skills, through the design of educational contexts and using a different methods that enhance diversity
Have we detected the most luminous ULX so far?
We report the XMM-Newton detection of a moderately bright X-ray source
superimposed on the outer arms of the inactive spiral galaxy MCG-03-34-63
(z=0.0213). It is clearly offset from the nucleus (by about 19'') but well
within the D25 ellipse of the galaxy, just along its bar axis. The field has
also been observed with the HST enabling us to compute a lower limit of > 94 on
the X-ray to optical flux ratio which, together with the X-ray spectrum of the
source, argues against a background AGN. On the other hand, the detection of
excess X-ray absorption and the lack of a bright optical counterpart argue
against foreground contamination. Short-timescale variability is observed,
ruling out the hypothesis of a particularly powerful supernova. If it is
associated with the apparent host galaxy, the source is the most powerful ULX
detected so far with a peak luminosity of 1.35x10^41 erg/s in the 0.5-7 keV
band. If confirmed by future multi-wavelength observations, the inferred
bolometric luminosity (about 3x10^41 erg/s) requires a rather extreme beaming
factor (larger than 115) to accommodate accretion onto a stellar-mass black
hole of 20 solar masses and the source could represent instead one of the best
intermediate-mass black hole candidate so far. If beaming is excluded, the
Eddington limit implies a mass of >2300 solar masses for the accreting compact
object.Comment: MNRAS Letters in press; minor correction at the end of Section
Simbol-X Background Minimization: Mirror Spacecraft Passive Shielding Trade-Off Study
The present work shows a quantitative trade-off analysis of the Simbol-X
Mirror Spacecraft (MSC) passive shielding, in the phase space of the various
parameters: mass budget, dimension, geometry, and composition. A simplified
physical (and geometrical) model of the sky screen, implemented by means of a
GEANT4 simulation, has been developed to perform a performance-driven mass
optimization and evaluate the residual background level on Simbol-X focal
plane.Comment: 3 pages, 6 figures, to appear in the proceedings of the second
Simbol-X International Symposium "Simbol-X - Focusing on the Hard X-ray
Universe", AIP Conf. Proc. Series, P. Ferrando and J. Rodriguez ed
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