4,663 research outputs found
Hidden AGNs in Early-Type Galaxies
We present a stacking analysis of the complete sample of Early Type Galaxies
(ETGs) in the \textit{Chandra} COSMOS (C-COSMOS) survey, to explore the nature
of the X-ray luminosity in the redshift and stellar luminosity ranges
and {10}^{9}. Using established
scaling relations, we subtract the contribution of X-ray binary populations, to
estimate the combined emission of hot ISM and AGN. To discriminate between the
relative importance of these two components, we (1) compare our results with
the relation observed in the local universe for
hot gaseous halos emission in ETGs, and (2) evaluate the spectral signature of
each stacked bin. We find two regimes where the non-stellar X-ray emission is
hard, consisten t with AGN emission. First, there is evidence of hard, absorbed
X-ray emission in stacked bins including relatively high z () ETGs
with average high X-ray luminosity (L_{X-LMXB}\gtrsim 6\times{10}^{42}\mbox{
erg}/\mbox{s}). These luminosities are consistent with the presence ofhighly
absorbed "hidden" AGNs in these ETGs, which are not visible in their optical-IR
spectra and spectral energy distributions. Second, confirming the early
indication from our C-COSMOS study of X-ray detected ETGs, we find
significantly enhanced X-ray luminoaity in lower stellar mass ETGs
(L_K\lesssim{10}^{11}L_{\astrosun}), relative to the local
relation. The stacked spectra of these ETGs also
suggest X-ray emission harder than expected from gaseous hot halos. This
emission is consistent with inefficient accretion
onto M_{BH}\sim
{10}^{6}-{10}^{8}\,M_{\astrosun}.Comment: 22 pages, 7 figures, 2 tables. Accepted for publications on Ap
Impressive long-term response with pertuzumab and trastuzumab in HER2-positive breast cancer with brain metastasis
This is a case report of a 40-year-old woman who, after conservative breast cancer treatment, developed a HER2 positive solitary brain metastasis in the left temporal lobe, without extracranial disease. She underwent surgery resection followed by stereotactic radiotherapy and, because of early brain progression, she was submitted to the first line therapy with pertuzumab, trastuzumab and weekly paclitaxel. After six months of treatment, a brain magnetic resonance imaging revealed a complete disappearance of brain recurrence, which persisted for more than 24 months
Early-type galaxies in the Chandra COSMOS Survey
We study a sample of 69 X-ray detected Early Type Galaxies (ETGs), selected
from the Chandra COSMOS survey, to explore the relation between the X-ray
luminosity of hot gaseous halos (L_X, gas) and the integrated stellar
luminosity (L_K) of the galaxies, in a range of redshift extending out to
z=1.5. In the local universe a tight steep relationship has been stablished
between these two quantities (L_X,gas~ L_K^4.5) suggesting the presence of
largely virialized halos in X-ray luminous systems. We use well established
relations from the study of local universe ETGs, together with the expected
evolution of the X-ray emission, to subtract the contribution of low mass X-ray
binary populations (LMXBs) from the X-ray luminosity of our sample. Our
selection minimizes the presence of active galactic nuclei (AGN), yielding a
sample representative of normal passive COSMOS ETGs; therefore the resulting
luminosity should be representative of gaseous halos, although we cannot
exclude other sources such as obscured AGN, or enhanced X-ray emission
connected with embedded star formation in the higher z galaxies. We find that
most of the galaxies with estimated L_X<10^42 erg/s and z<0.55 follow the
L_X,gas- L_K relation of local universe ETGs. For these galaxies, the
gravitational mass can be estimated with a certain degree of confidence from
the local virial relation. However, the more luminous (10^42<L_X<10^43.5 erg/s)
and distant galaxies present significantly larger scatter; these galaxies also
tend to have younger stellar ages. The divergence from the local L_X,gas - L_K
relation in these galaxies implies significantly enhanced X-ray emission, up to
a factor of 100 larger than predicted from the local relation. We discuss the
implications of this result for the presence of hidden AGN, and the evolution
of hot halos, in the presence of nuclear and star formation feedback.Comment: 29 pages, 10 figures, accepted for publication on ApJ on May 27 201
A critical review on the role of food and nutrition in the energy balance
The mass media has increasingly frequently suggested to the general population that specific foods or nutritional schemes are able to affect both human metabolism and energy expenditure, thus facilitating weight loss. This critical review is aimed at assessing available evidence on the roles of nutrients, food and dietary regimens in energy intake and energy expenditure. We queried the National Library of Medicine, the Cochrane Library, Excerpta Medica dataBASEand the Cumulative Index to Nursing and Allied Health Literature database, and a search strategy was performed by using database-specific subject headings and keywords. We found that available scientific evidence on these topics is scarce, and that the limited number of available studies often have poor methodological quality. Only a few foods show beneficial effects on metabolism and energy expenditure, as the human energy balance is complex and multifactorial. Finally, microbiota may interfere with the intake, use and expenditure of energy in the human body. Conclusive evidence is still lacking, and, at present, it is not possible to identify a food or a diet with a significant impact on human energy expenditure
Radiation hardness of small-pitch 3D pixel sensors up to HL-LHC fluences
A new generation of 3D silicon pixel detectors with a small pixel size of
5050 and 25100 m is being developed for the HL-LHC
tracker upgrades. The radiation hardness of such detectors was studied in beam
tests after irradiation to HL-LHC fluences up to
n/cm. At this fluence, an operation voltage of only 100 V
is needed to achieve 97% hit efficiency, with a power dissipation of 13
mW/cm at -25C, considerably lower than for previous 3D sensor
generations and planar sensors.Comment: 5 pages, 2 figures, Proceedings of TIPP 2017, Beijing (International
Conference on The Technology and Instrumentation in Particle Physics 2017
AGN activity and the misaligned hot ISM in the compact radio elliptical NGC4278
The analysis of a deep (579 ks) Chandra ACIS pointing of the elliptical
galaxy NGC4278, which hosts a low luminosity AGN and compact radio emission,
allowed us to detect extended emission from hot gas out to a radius of \sim 5
kpc, with a 0.5--8 keV luminosity of 2.4x10^{39} erg/s. The emission is
elongated in the NE-SW direction, misaligned with respect to the stellar body,
and aligned with the ionized gas, and with the Spitzer IRAC 8\mum non-stellar
emission. The nuclear X-ray luminosity decreased by a factor of \sim 18 since
the first Chandra observation in 2005, a dimming that enabled the detection of
hot gas even at the position of the nucleus. Both in the projected and
deprojected profiles, the gas shows a significantly larger temperature (kT=0.75
keV) in the inner \sim 300 pc than in the surrounding region, where it stays at
\sim 0.3 keV, a value lower than expected from standard gas heating
assumptions. The nuclear X-ray emission is consistent with that of a low
radiative efficiency accretion flow, accreting mass at a rate close to the
Bondi one; estimates of the power of the nuclear jets require that the
accretion rate is not largely reduced with respect to the Bondi rate. Among
possibile origins for the central large hot gas temperature, such as
gravitational heating from the central massive black hole and a recent AGN
outburst, the interaction with the nuclear jets seems more likely, especially
if the latter remain confined, and heat the nuclear region frequently. The
unusual hot gas distribution on the galactic scale could be due to the
accreting cold gas triggering the cooling of the hot phase, a process also
contributing to the observed line emission from ionize gas, and to the hot gas
temperature being lower than expected; alternatively, the latter could be due
to an efficiency of the type Ia supernova energy mixing lower than usually
adopted.Comment: 48 pages, submitted to Ap
3D sensors for the HL-LHC
In order to increase its discovery potential, the Large Hadron Collider (LHC)
accelerator will be upgraded in the next decade. The high luminosity LHC
(HL-LHC) period demands new sensor technologies to cope with increasing
radiation fluences and particle rates. The ATLAS experiment will replace the
entire inner tracking detector with a completely new silicon-only system. 3D
pixel sensors are promising candidates for the innermost layers of the Pixel
detector due to their excellent radiation hardness at low operation voltages
and low power dissipation at moderate temperatures. Recent developments of 3D
sensors for the HL-LHC are presented.Comment: 8 pages, 5 figures, International Workshops on Radiation Imaging
Detectors 201
Electrical plasmon detection in graphene waveguides
We present a simple device architecture that allows all-electrical detection
of plasmons in a graphene waveguide. The key principle of our electrical
plasmon detection scheme is the non-linear nature of the hydrodynamic equations
of motion that describe transport in graphene at room temperature and in a wide
range of carrier densities. These non-linearities yield a dc voltage in
response to the oscillating field of a propagating plasmon. For illustrative
purposes, we calculate the dc voltage arising from the propagation of the
lowest-energy modes in a fully analytical fashion. Our device architecture for
all-electrical plasmon detection paves the way for the integration of graphene
plasmonic waveguides in electronic circuits.Comment: 9 pages, 3 figure
- âŠ